for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> CHEMISTRY (Total: 843 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (596 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (26 journals)
    - INORGANIC CHEMISTRY (41 journals)
    - ORGANIC CHEMISTRY (45 journals)
    - PHYSICAL CHEMISTRY (66 journals)

CHEMISTRY (596 journals)

The end of the list has been reached or no journals were found for your choice.
Journal Cover Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
  [SJR: 0.628]   [H-I: 64]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1386-1425
   Published by Elsevier Homepage  [2969 journals]
  • Spectroscopic investigation of the interaction between G-quadruplex of
           KRAS promoter sequence and three isoquinoline alkaloids
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Li-Na Wen, Meng-Xia Xie
      KRAS promoter can form G-quadruplex structure and regulate gene transcription. The drugs which can bind with G-quadruplex of KRAS promoter may be potential remedy for treatment of cancers associated with KRAS mutation. The interaction mechanism between the G-quadruplex of KRAS promoter and three isoquinoline alkaloids (jatrorrhizine, berberine and sanguinarine) has been investigated by UV-visible, fluorescence and circular dichroism spectroscopic methods. The results showed that the three alkaloids can form complexes with G-quadruplex KRAS promoter with the molecular ratio of 1:1, and the binding constants were (0.90±0.16)×106 Lmol−1, (0.93±0.21)×106 Lmol−1 and (1.16±0.45)×106 Lmol−1 for jatrorrhizine, berberine and sanguinarine. The absorption spectra, KI quenching and fluorescence anisotropy and polarization studies suggested jatrorrhizine and berberine interacted with G-quadruplex by not only end-stacking binding mode but also grooves or loops binding mode, while sanguinarine by end-stacking binding mode. Sanguinarine was more beneficial to maintain the stability and parallel conformation of KRAS promoter G-quadruplex. MTT assay was performed to evaluate antiproliferation effects of the three isoquinoline alkaloids on SW620 cells, and the antiproliferation effects of the three alkaloids were sanguinarine > berberine > jatrorrhizine. All the three alkaloids can bind with KRAS promoter G-quadruplex, and sanguinarine had the better binding property and antiproliferation effects on SW620 cells. The results obtained are meaningful to explore potential reagents targeting the parallel G-quadruplex structure of KRAS promoter for gene theraphy of colorectal carcinomas.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Biologically green synthesized silver nanoparticles as a facile and rapid
           label-free colorimetric probe for determination of Cu2+ in water samples
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Sedigheh Basiri, Ali Mehdinia, Ali Jabbari
      A highly sensitive and cost-effective colorimetric sensing platform for the selective trace analysis of Cu2+ ions was developed based on the accelerated etching of Riboflavin stabilized silver nanoparticles (R/AgNPs). The R/AgNPs were prepared from the Cucumis melo juice by a green chemistry approach. The bio-synthesized AgNPs were studied by UV–Vis spectroscopy and showed an intense absorption band at 404nm that were further confirmed by FTIR and EDS analysis. Simultaneous presence of Cu2+ and thiosulfate decreased the absorption intensity of green synthesized AgNPs which resulted in sensitive and selective determination of Cu2+. The selectivity of R/AgNPs detection system for Cu2+ was excellent. Furthermore, the method offered a wide linear detection range from 5nM to 100nM with a detection limit of 1.12nM. Surprisingly, it was a quick approach and the decolorization of the R/AgNPs solutions occurred only within 5min. Our results clearly indicate these R/AgNPs could be used as an efficient probe for the colorimetric sensing of Cu2+ in environmental water samples.


      PubDate: 2016-08-26T04:22:02Z
       
  • PARAFAC analysis of IBIL spectra from silver ion exchanged glasses
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): G. Valotto, E. Cattaruzza, M. Mardegan, A. Quaranta
      In this work we present for the first time an application of PARAllel FACtor (PARAFAC) analysis to the investigation of Ion Beam Induced Luminescence (IBIL) spectra of Ag+ ↔Na+ ion exchanged silicate glasses, in order to check the possibility to obtain additional information on the formation of silver aggregates under ion irradiation by a proper statistical rearrangement of experimental spectra. We decomposed the data by PARAFAC taking into account both IBIL emission features and their evolution as a function of the time. Shape and trend under irradiation of the extracted components were correlated to silver concentration and aggregates in the investigated systems. Strength and weakness of this statistical approach applied to IBIL spectra recorded as a function of time were evidenced and discussed.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • New water soluble Hg2+ selective fluorescent calix[4]arenes: Synthesis and
           application in living cells imaging
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Mehmet Oguz, Asif Ali Bhatti, Serdar Karakurt, Mehmet Aktas, Mustafa Yilmaz
      The present study demonstrates the synthesis of water-soluble fluorescent calix[4]arenes (6 and 7) and its application in living cell imaging for Hg2+ detection at a low level. The synthesized fluorescent ligands 6 and 7 were characterized by 1H NMR technique. The fluorescent study showed both water soluble ligands were Hg2+ selective and follow photo-induced electron transfer (PET) process. From the fluorimeter titration experiment detection limit was calculated as 1.14×10−5 and 3.42×10−5 for ligand 6 and 7, respectively. From the Benesi-Hildebrand plot binding constant values were evaluated as 666.7 and 733.3M−1 for 6 and 7, respectively. The interactions between ligands 6 and 7 and Hg2+ were also demonstrated in living cells, SW-620, using Fluorescent Cell Imager. While ligands 6 and 7 alone show fluorescent properties, they loss their action with the presence of Hg2+ in SW-620 cells.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Selective photo-dissociative ionization of methane molecule with TDDFT
           study
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): E. Irani, A. Anvari, R. Sadighi-Bonabi
      Three dimensional calculation of control dynamics for finding the optimized laser filed is formulated using an iterative method and time-dependent density functional approach. An appropriate laser pulse is designed to control the desired products in the dissociation of methane molecule. The tailored laser pulse profile, eigenstate distributions and evolution of the efficient occupation numbers are predicted and exact energy levels of this five-atomic molecule is obtained. Dissociation rates of up to 78%, 80%, 90%, and 82% for CH2 +, CH+, C+ and C++ are achieved. Based on the present approach one can reduce the controlling costs.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Synthesis, electronic structure and spectral fluorescent properties of
           vinylogous merocyanines derived from 1,3-dialkyl-benzimidazole and
           malononitrile
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Andrii V. Kulinich, Elena K. Mikitenko, Alexander A. Ishchenko
      A vinylogous series of merocyanines were synthesized with 1,3-dibutyl-benzimidazole and malononitrile residues as the donor and acceptor terminal groups. These dyes do not comprise carbonyl groups, which are prone to the strong specific solvation by polar solvents up to hydrogen bond formation, and nevertheless they possess distinct reversed solvatochromism, i.e. their molecules have very high dipolarity. At that, they are soluble in a wide range of solvents from n-hexane to ethanol and do not aggregate readily. They were studied thoroughly by UV/Vis, fluorescence, IR, and NMR spectroscopy methods. Their structure and spectral properties in the ground and excited fluorescent states were modelled at the DFT level both in vacuum and in solvents of various polarities by using the PCM solvent field simulation. The calculations were performed using several hybrid functionals (B3LYP, CAM-B3LYP, and wB97XD) and the split-valence 6-31G (d,p) basis set.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Time-dependent density functional theory study on the excited-state
           hydrogen-bonding characteristics of polyaniline in aqueous environment
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Yahong Zhang, Yuping Duan, Jin Liu
      A theoretical study was carried out to study the excited-state of hydrogen-bonding characteristics of polyaniline (PANI) in aqueous environment. The hydrogen-bonded PANI-H2O complexes were studied using first-principles calculations based on density functional theory (DFT). The electronic excitation energies and the corresponding oscillator strengths of the low-lying electronically excited states for hydrogen-bonded complexes were calculated by time-dependent density functional theory (TDDFT). The ground-state geometric structures were optimized, and it is observed that the intermolecular hydrogen bonds CN⋯HO and NH⋯OH were formed in PANI-H2O complexes. The formed hydrogen bonds influenced the bond lengths, the charge distribution, as well as the spectral characters of the groups involved. It was concluded that all the hydrogen-bonded PANI-H2O complexes were primarily excited to the S1 states with the largest oscillator strength. In addition, the orbital transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) involved intramolecular charge redistribution resulting to increase the electron density of the quinonoid rings.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Development and validation of multivariate calibration methods for
           simultaneous estimation of Paracetamol, Enalapril maleate and
           hydrochlorothiazide in pharmaceutical dosage form
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Veena D. Singh, Sanjay J. Daharwal
      Three multivariate calibration spectrophotometric methods were developed for simultaneous estimation of Paracetamol (PARA), Enalapril maleate (ENM) and Hydrochlorothiazide (HCTZ) in tablet dosage form; namely multi-linear regression calibration (MLRC), trilinear regression calibration method (TLRC) and classical least square (CLS) method. The selectivity of the proposed methods were studied by analyzing the laboratory prepared ternary mixture and successfully applied in their combined dosage form. The proposed methods were validated as per ICH guidelines and good accuracy; precision and specificity were confirmed within the concentration range of 5–35μgmL−1, 5–40μgmL−1 and 5–40μgmL−1of PARA, HCTZ and ENM, respectively. The results were statistically compared with reported HPLC method. Thus, the proposed methods can be effectively useful for the routine quality control analysis of these drugs in commercial tablet dosage form.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Through-space electronic communication of zinc phthalocyanine with
           substituted [60]Fullerene bearing O2Nxaza-crown macrocyclic ligands
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Bahram Ghanbari, Leila Shahhoseini, Niloofar Mahlooji, Parisa Gholamnezhad, Zahra Taheri Rizi
      Two new macrocyclic ligands containing 17- and 19-membered O2N3-donor aza-crowns anchored to [60]Fullerene were synthesized and characterized by employing HPLC, electrospray ionization mass (ESI-MS), 1H and 13C NMR, UV–vis, IR spectroscopies, as well as powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA) in solid state. TGA measurements revealed that upon linking each of these macrocycle rings to [60]Fullerene, the decomposition point measured for [60]Fullerene moiety was increased, indicating on the promoted stability of [60]Fullerene backbone during binding to these macrocyclic ligands. Moreover, the ground state non-covalent interactions of [60]Fullerene derivatives of O2Nx (x=2, and 3) aza-crown macrocyclic ligands namely, L 1 –L 4 with zinc phthalocyanine (ZnPc) were also investigated by UV–vis absorption, steady state and time resolved fluorescence spectrophotometry in N-methyl-2-pyrrolidone (NMP). The calculation of Stern-Volmer constants (K SV) indicated on existence of an efficient quenching mechanism comprising of the excited singlet state of ZnPc in the presence of L 1 –L 4 . The observation of an appropriate correlation between decrease in fluorescence intensity and lifetime parameters led us to propose the occurrence of a static mechanism for the fluorescence quenching of ZnPc in the presence of L 1 –L 3 . The binding constants (K BH) of L 1 –L 4 /ZnPc were also determined applying the fluorescence quenching experiments. Meanwhile, the incompatibility of both K SV and K BH values found for L 4 was also described in terms of structural features using DFT calculations using the B3LYP functional and 6-31G* basis set.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Interaction between fluorescein isothiocyanate and carbon dots: Inner
           filter effect and fluorescence resonance energy transfer
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Huabing Liu, Chaoyong Xu, Yanli Bai, Lin Liu, Dongmei Liao, Jiangong Liang, Lingzhi Liu, Heyou Han
      Carbon dots (CDs) have been widely used for the preparation of multifunctional probes by conjugation with organic fluorescent dyes. However, the effect of organic fluorescent dyes on CDs still remains poorly understood. Herein, the effect of fluorescein isothiocyanate (FITC) on CDs was explored by spectroscopic techniques at pH5.1, 7.0 and 9.0. The fluorescent intensity of CDs was found to be quenched gradually after mixing directly with different concentrations of FITC, but the fluorescent lifetime of CDs remained unchanged. According to the results of UV–vis absorption spectra and fluorescent lifetime measurements, a pH-dependent inner filter effect (IFE) between CDs and FITC was proposed. However, the fluorescent lifetime of CDs deceased after their conjugation with FITC, implying the fluorescence resonance energy transfer (FRET) between CDs and FITC. This study has revealed two different effects of FITC on CDs with varying pH values and provided useful theoretical guidelines for further research on the interaction between other nanoparticles and fluorophores.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Rapid measurement of epimedin A, epimedin B, epimedin C, icariin, and
           moisture in Herba Epimedii using near infrared spectroscopy
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Yue Yang, Xuesong Liu, Weili Li, Ye Jin, Yongjiang Wu, Jiyu Zheng, Wentao Zhang, Yong Chen
      In this work, near infrared (NIR) spectroscopy was used in combination with chemometrics to determine the epimedin A, epimedin B, epimedin C, icariin, and moisture contents of Herba Epimedii. The variable selection method genetic algorithm (GA) and regression tool support vector machine (SVM) were used to improve the model performance. Four different calibration models, namely Full-PLS, GA-PLS, Full-SVM, and GA-SVM, were established, and their performances in terms of prediction accuracy and model robustness were systemically studied and compared. In conclusion, the performances of the models based on the efficient variables selected through GA were better than those based on full spectra, and the nonlinear models were superior over the linear models. In addition, the GA-SVM model demonstrated the optimal performance in predicting five quality parameters (viz. epimedin A, epimedin B, epimedin C, icariin, and moisture). For GA-SVM, the determination coefficient (R p 2), root-mean-square error (RMSEP), and residual predictive deviation (RPD) for the prediction set were 0.9015, 0.0268%, and 2.20 for epimedin A; 0.9089, 0.0656%, and 3.08 for epimedin B; 0.9056, 0.1787%, and 3.18 for epimedin C; 0.8192, 0.0657%, and 2.26 for icariin; and 0.9367, 0.2062%, and 4.12 for moisture, correspondingly. Results indicated that NIR spectroscopy coupled with GA-SVM calibration can be used as a reliable alternative strategy to measure the epimedin A, epimedin B, epimedin C, icariin, and moisture contents of Herba Epimedii because this technique is fast, economic, and nondestructive compared with traditional chemical methods.
      Graphical abstract image

      PubDate: 2016-08-26T04:22:02Z
       
  • Is it possible to find presence of lactose in pharmaceuticals? —
           Preliminary studies by ATR-FTIR spectroscopy and chemometrics
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): A. Banas, K. Banas, S.M.P. Kalaiselvi, B. Pawlicki, W.M. Kwiatek, M.B.H. Breese
      Lactose and saccharose have the same molecular formula; however, the arrangement of their atoms is different. A major difference between lactose and saccharose with regard to digestion and processing is that it is not uncommon for individuals to be lactose intolerant (around two thirds of the population has a limited ability to digest lactose after infancy), but it is rather unlikely to be saccharose intolerant. The pharmaceutical industry uses lactose and saccharose as inactive ingredients of drugs to help form tablets because of their excellent compressibility properties. Some patients with severe lactose intolerance may experience symptoms of many allergic reactions after taking medicine that contains this substance. People who are specifically “allergic” to lactose (not just lactose intolerant) should not use tablets containing this ingredient. Fourier Transform Infrared (FTIR) spectroscopy has a unique chemical fingerprinting capability and plays a significant important role in the identification and characterization of analyzed samples and hence has been widely used in pharmaceutical science. However, a typical FTIR spectrum collected from tablets contains a myriad of valuable information hidden in a family of tiny peaks. Powerful multivariate spectral data processing can transform FTIR spectroscopy into an ideal tool for high volume, rapid screening and characterization of even minor tablet components. In this paper a method for distinction between FTIR spectra collected for tablets with or without lactose is presented. The results seem to indicate that the success of identifying one component in FTIR spectra collected for pharmaceutical composition (that is tablet) is largely dependent on the choice of the chemometric technique applied.
      Graphical abstract image

      PubDate: 2016-08-21T02:35:57Z
       
  • Application of linear and non-linear methods for modeling removal
           efficiency of textile dyes from aqueous solutions using magnetic Fe3O4
           impregnated onto walnut shell
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Motahare Ashrafi, Mansour Arab Chamjangali, Ghadamali Bagherian, Nasser Goudarzi
      The performance of the Nano-magnetite Fe3O4 impregnated onto walnut shell (Fe3O4-WNS), which possessed the adsorption features of walnut shell and the magnetic property of Fe3O4, was investigated for the elimination of the methyl violet and Rhodamine 6G from contaminated aqueous solutions. The effects of different experimental variables on the removal efficiency of the cited dyes were examined. Then these variables were used as the inputs to generate linear and non-linear models such as the multiple linear regression, random forest, and artificial neural network to predict the removal efficiency of these dye species at different experimental conditions. The validation studies of these models were performed using the test set, which was not present in the modeling procedure. It was found that ANN had a higher ability to predict the adsorption process under different experimental conditions, and could be applied for the development of an automated dye wastewater removal plant. Also the maximum adsorption capacity (qmax) indicated that the qmax value for Fe3O4-WNS for removal of cationic dyes was comparable or better than that for some reported adsorbents. Also it should be cited that exhausted Fe3O4-WNS was regenerated using dishwashing liquid, and reused for removal of the cited dye species from aqueous solutions.
      Graphical abstract image

      PubDate: 2016-08-21T02:35:57Z
       
  • Experimental and theoretical studies of the influence of solvent polarity
           on the spectral properties of two push-pull oxazol-5-(4H)-one compounds
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Beata Jędrzejewska, Przemysław Krawczyk, Marek Józefowicz
      Spectral and photophysical properties of two derivatives of the 2-phenyl-1,3-oxazol-5(4H)-ones were studied in 17 solvents of different polarity. These compounds have either push-pull non-centrosymmetric or C3-symmetric structures with electron-withdrawing groups (2-phenyl-oxazolone) introduced onto the triphenylamine. It has been found that their spectral and photophysical properties depend on the structure of the compounds and on the solvent polarity. The non-radiative relaxation process is facilitated by an increase of the solvent polarity. The changes in the electronic absorption and fluorescence maximum positions with solvent polarity were analyzed applying different solvent polarity parameters based on Lippert-Mataga, McRae, Bakhshiev and Kawski theories or E T N scale. The long-wavelength absorption band positions exhibit a slight dependence on the solvent, whereas the fluorescence spectra demonstrate substantial positive solvatochromism. It was found that the position of the electronic absorption band depends mainly on the solute polarizability (related to the solvent refraction index function f(n2)=(n2–1)/(2n2 +1)), whereas the solvent polarity influences the position of the fluorescence band. Quantum chemical calculations of the transition energies and dipole moments at the DFT level have been also performed. The difference between the first excited and ground state dipole moments was found experimentally to be 10.8 D and 13.0 D according to Bakhshiev's model. The experimental values of Δμ were compared to that one obtained from theoretical calculations for various solvents.
      Graphical abstract image

      PubDate: 2016-08-21T02:35:57Z
       
  • Synthesis, characterization of 1,2,4-triazole Schiff base derived 3d-metal
           complexes: Induces cytotoxicity in HepG2, MCF-7 cell line, BSA binding
           fluorescence and DFT study
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Prateek Tyagi, Monika Tyagi, Swati Agrawal, Sulekh Chandra, Himanshu Ojha, Mallika Pathak
      Two novel Schiff base ligands H 2 L 1 and H 2 L 2 have been synthesized by condensation reaction of amine derivative of 1,2,4-triazole moiety with 2-hydroxy-4-methoxybenzaldehyde. Co(II), Ni(II), Cu(II) and Zn(II) of the synthesized Schiff bases were prepared by using a molar ratio of ligand:metal as 1:1. The structure of the Schiff bases and synthesized metal complexes were established by 1H NMR, UV–Vis, IR, Mass spectrometry and molar conductivity. The thermal stability of the complexes was study by TGA. Fluorescence quenching mechanism of metal complexes 1–4 show that Zn(II) and Cu(II) complex binds more strongly to BSA. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. The spectral data shows that the ligands behaves as binegative tridentate. On the basis of the spectral studies, TGA and DFT data an octahedral geometry has been assigned for Co(II), Ni(II), square planar for Cu(II) and tetrahedral for Zn(II) complexes. The anticancer activity were screened against human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2). Result indicates that metal complexes shows increase cytotoxicity in proliferation to cell lines as compared to free ligand.
      Graphical abstract image

      PubDate: 2016-08-21T02:35:57Z
       
  • Characterizing harmful advanced glycation end-products (AGEs) and
           ribosylated aggregates of yellow mustard seed phytocystatin: Effects of
           different monosaccharides
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Azaj Ahmed, Anas Shamsi, Bilqees Bano
      Advanced glycation end products (AGEs) are at the core of variety of diseases ranging from diabetes to renal failure and hence gaining wide consideration. This study was aimed at characterizing the AGEs of phytocystatin isolated from mustard seeds (YMP) when incubated with different monosaccharides (glucose, ribose and mannose) using fluorescence, ultraviolet, circular dichroism (CD) spectroscopy and microscopy. Ribose was found to be the most potent glycating agent as evident by AGEs specific fluorescence and absorbance. YMP exists as a molten globule like structure on day 24 as depicted by high ANS fluorescence and altered intrinsic fluorescence. Glycated YMP as AGEs and ribose induced aggregates were observed at day 28 and 32 respectively. In our study we have also examined the anti-aggregative potential of polyphenol, resveratrol. Our results suggested the anti-aggregative behavior of resveratrol as it prevented the in vitro aggregation of YMP, although further studies are required to decode the mechanism by which resveratrol prevents the aggregation.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Fluorescence spectroscopic and molecular docking studies of the binding
           interaction between the new anaplastic lymphoma kinase inhibitor
           crizotinib and bovine serum albumin
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Ali S. Abdelhameed, Amer M. Alanazi, Ahmed H. Bakheit, Hany W. Darwish, Hazem A. Ghabbour, Ibrahim A. Darwish
      Binding of the recently introduced anti-cancer drug, crizotinib (CRB) with the bovine serum albumin (BSA) was comprehensively studied with the aid of fluorescence and UV–Vis spectroscopic as well as molecular docking techniques. The collective results of the study under the simulated physiological conditions proposed a static type of binding occurring between the CRB and BSA with binding constants of 104 Lmol−1. BSA conformational changes were investigated using three dimensional (3D) and synchronous fluorescence measurements. Moreover, the results of site marker competitive experiments and molecular docking, it could be deduced that CRB was inserted into the subdomain IIA (site I) of BSA yielding a more stabilized system. This was further confirmed with the molecular docking results which revealed that CRB is located in the active site residues Try149, Glu152, Ser191, Arg194, Arg198, Trp213, Arg217, Arg256, His287, Ala290, Glu291, Ser343, Asp450 within a radius of 6Å. Combining the molecular docking studies and the computed thermodynamic parameters, it can be inferred that hydrophobic and electrostatic interactions are the major binding forces involved in formation of the CRB-BSA complex.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • A novel flow injection spectrophotometric method using plant extracts as
           green reagent for the determination of doxycycline
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Sysay Palamy, Wirat Ruengsitagoon
      A novel flow injection spectrophotometric method was developed for the determination of doxycycline in pharmaceutical preparations using iron(III) contained in extracts from plants. The assay was based on the complex formed between doxycycline and iron(III) characterized by an absorption maximum at 435nm. The calibration graphs obtained over the doxycycline concentration range 5–250μgmL−1 gave correlation coefficients of 0.9979, 0.9987 and 0.9987 with the three green reagents prepared from Senna alata (L.) Roxb. (S. alata), Polygonum hydropiper L. (P. hydropiper) or Diplazium esculentum (Retz.) Sw. (D. esculentum), respectively. The relative standard deviations of the repeatability was <2.00%. The percentage recoveries were in the range of 98.27–101.03%. Doxycycline contents obtained by this new method and by the reference methods reported in literature were in agreement at 95% confidence level with the paired t-test. The sample throughput was 36h−1 for each green reagent.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Time resolved fluorescence of cow and goat milk powder
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Mariana P. Brandao, Virgílio de Carvalho dos Anjos, Maria José V. Bell.
      Milk powder is an international dairy commodity. Goat and cow milk powders are significant sources of nutrients and the investigation of the authenticity and classification of milk powder is particularly important. The use of time-resolved fluorescence techniques to distinguish chemical composition and structure modifications could assist develop a portable and non-destructive methodology to perform milk powder classification and determine composition. This study goal is to differentiate milk powder samples from cows and goats using fluorescence lifetimes. The samples were excited at 315nm and the fluorescence intensity decay registered at 468nm. We observed fluorescence lifetimes of 1.5±0.3, 6.4±0.4 and 18.7±2.5ns for goat milk powder; and 1.7±0.3, 6.9±0.2 and 29.9±1.6ns for cow's milk powder. We discriminate goat and cow powder milk by analysis of variance using Fisher's method. In addition, we employed quadratic discriminant analysis to differentiate the milk samples with accuracy of 100%. Our results suggest that time-resolved fluorescence can provide a new method to the analysis of powder milk and its composition.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Visible upconversion in Er3+/Yb3+ co-doped LaAlO3 phosphors
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Vijay Singh, V.K. Rai, N. Singh, M.S. Pathak, M. Rathaiah, V. Venkatramu, Rahul V. Patel, Pramod K. Singh, S.J. Dhoble
      The Er3+ doped and Er3+/Yb3+ co-doped LaAlO3 phosphors have been synthesized by the combustion method and characterized their structural, morphological, elemental, vibrational and optical properties. The optical absorption and upconversion properties of the synthesized phosphors have been studied. Upon co-doping Yb3+ ions into Er3+:LaAlO3, the blue, green and red upconversion emissions of Er3+ ions have been enhanced about . . . ~20, ~46 and ~22 times, under 978nm laser excitation. The observed upconversion emissions could be due to excited state absorption in Er3+:LaAlO3, whereas energy transfer is dominant mechanism in Er3+/Yb3+:LaAlO3 phosphors. The tuning in the color emitted from the synthesized phosphors towards the green region has been found due to incorporation of the Yb3+ ions. With increase in the pump power, the color emitted from the co-doped phosphor is not tuned significantly, showing its applicability in making the green display devices.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Investigation of different spectrophotometric and chemometric methods for
           determination of entacapone, levodopa and carbidopa in ternary mixture
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Maha F. Abdel-Ghany, Lobna A. Hussein, Miriam F. Ayad, Menatallah M. Youssef
      New, simple, accurate and sensitive UV spectrophotometric and chemometric methods have been developed and validated for determination of Entacapone (ENT), Levodopa (LD) and Carbidopa (CD) in ternary mixture. Method A is a derivative ratio spectra zero-crossing spectrophotometric method which allows the determination of ENT in the presence of both LD and CD by measuring the peak amplitude at 249.9nm in the range of 1–20μgmL−1. Method B is a double divisor-first derivative of ratio spectra method, used for determination of ENT, LD and CD at 245, 239 and 293nm, respectively. Method C is a mean centering of ratio spectra which allows their determination at 241, 241.6 and 257.1nm, respectively. Methods B and C could successfully determine the studied drugs in concentration ranges of 1–20μgmL−1 for ENT and 10–90μgmL−1 for both LD and CD. Methods D and E are principal component regression and partial least-squares, respectively, used for the simultaneous determination of the studied drugs by using seventeen mixtures as calibration set and eight mixtures as validation set. The developed methods have the advantage of simultaneous determination of the cited components without any pre-treatment. All the results were statistically compared with the reported methods, where no significant difference was observed. The developed methods were satisfactorily applied to the analysis of the investigated drugs in their pure form and in pharmaceutical dosage forms.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Aptamer biosensor for Salmonella typhimurium detection based on
           luminescence energy transfer from Mn2+-doped NaYF4:Yb, Tm upconverting
           nanoparticles to gold nanorods
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Keyi Cheng, Jianguo Zhang, Liping Zhang, Lun Wang, Hongqi Chen
      A highly sensitive luminescent bioassay for the detection of Salmonella typhimurium was fabricated using Mn2+-doped NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) as the donor and gold nanorods (Au NRs) as the acceptor and utilizing an energy transfer (LET) system. Mn2+-doped NaYF4:Yb,Tm UCNPs with a strong emission peak at 807nm were obtained by changing the doped ion ratio. Carboxyl-terminated Mn2+-doped NaYF4:Yb,Tm UCNPs were coupled with S. typhimurium aptamers, which were employed to capture and concentrate S. typhimurium. The electrostatic interactions shorten the distance between the negatively charged donor and the positively charged acceptor, which results in luminescence quenching. The added S. typhimurium leads to the restoration of luminescence due to the formation of UCNPs-aptamers-S. typhimurium, which repels the UCNPs-aptamers from the Au NRs. The LET system does not occur because of the nonexistence of the luminescence emission band of Mn2+-doped NaYF4:Yb,Tm UCNPs, which had large spectral overlap with the absorption band of Au NRs. Under optimal conditions, the linear range of detecting S. typhimurium was 12 to 5×105 cfu/mL (R=0.99). The limit of detection for S. typhimurium was as low as 11cfu/mL in an aqueous buffer. The measurement of S. typhimurium in milk samples was satisfied in accordance with the plate-counting method, suggesting that the proposed method was of practical value in the application of food security.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Structurally simple azo based chromogenic R1 for the selective sensing of
           cyanide ion in aqueous medium
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Palanisamy Kalpana, Sivalingam Suganya, Sivan Velmathi
      Structurally simple azo linked Schiff base R1 was synthesized and characterized using IR, 1H NMR and mass spectroscopic techniques. The selective sensing of cyanide anion over other anions such as fluoride, chloride, bromine, iodide, acetate, nitrate, hydrogen sulphate and dihydrogenphosphate was revealed by naked-eye color change and UV–vis spectra. Addition of CN− ions to the R1 showed a dramatic change in color from pale yellow to intense yellow along with the formation of a new band at 415nm in the absorption spectrum even in 100% aqueous medium. The interaction between R1 and cyanide was also investigated using 1H NMR titration study. The R1 showed limit of detection (LOD) up to micromolar level at 2.72×10−6 M. Job's plot reveals the existing binding mode of R1 and CN− ion in molar ratio of 1:1 (R1:CN−).
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Assignment of the vibrational spectra of the parent polysilsesquioxane
           (POSS): Octahydridosilasequioxane, H8Si8O12
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Stewart F. Parker
      Polysilsesquioxanes (POSS) are molecules with the empirical formula (RSiO1.5) n where R is a hydrogen atom or hydroxyl or an organic moiety such as an alkyl, alkene, acrylate or epoxide. The silicon atoms occupy the corners of a cube and oxygen atoms are located on the edges, the versatility of silsesquioxanes arises from the vacant fourth position of silicon. The choice of substituent enables a wide variety of properties to be engineered in a straightforward manner. The parent POSS is octasilsesquioxane, H8Si8O12, with R=H and n =8. The present work employs periodic density functional theory calculations in conjunction with all the available vibrational (infrared, Raman and inelastic neutron scattering) spectra to generate a complete assignment of all the modes of the parent POSS octasilsesquioxane and some of its isotopomers for both the free, (O h), molecule and the solid state material (C 3i site symmetry) including the forbidden and very weak modes. The latter are of interest because in less symmetrical silsesquioxanes, these modes will be activated.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Matrix isolation infrared spectroscopic study of 4-Pyridinecarboxaldehyde
           and of its UV-induced photochemistry
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Liesel Cluyts, Archna Sharma, Nihal Kuş, Kristien Schoone, Rui Fausto
      The structure, infrared spectrum, barrier to internal rotation, and photochemistry of 4-pyridinecarboxaldehyde (4PCA) were studied by low-temperature (10K) matrix isolation infrared spectroscopy and quantum chemical calculations undertaken at both Moller-Plesset to second order (MP2) and density functional theory (DFT/B3LYP) levels of approximation. The molecule has a planar structure (C s point group), with MP2/6-311++G(d,p) predicted internal rotation barrier of 26.6kJmol−1, which is slightly smaller than that of benzaldehyde (~30kJmol−1), thus indicating a less important electron charge delocalization from the aromatic ring to the aldehyde moiety in 4PCA than in benzaldehyde. A complete assignment of the infrared spectrum of 4PCA isolated in an argon matrix has been done for the whole 4000–400cm−1 spectral range, improving over previously reported data. Both the geometric parameters and vibrational frequencies of the aldehyde group reveal the relevance in this molecule of the electronic charge back-donation effect from the oxygen trans lone electron pair to the aldehyde CH anti-bonding orbital. Upon in situ UV irradiation of the matrix-isolated compound, prompt decarbonylation was observed, leading to formation of pyridine.
      Graphical abstract image

      PubDate: 2016-08-16T12:24:07Z
       
  • Synthesis and improved photochromic properties of pyrazolones in the solid
           state by incorporation of halogen
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Jixi Guo, Hui Yuan, Dianzeng Jia, Mingxi Guo, Yinhua Li
      Four novel photochromic pyrazolones have been prepared by introducing halogen atoms as substituents on the benzene ring. All as-synthesized compounds exhibited excellent reversible photochromic performances in the solid state. Upon UV light irradiation, the as-synthesized compounds can change their structures from E-form to K-form with yellow coloration. Further processed by heating, they rapidly reverted to their initial states at 120°С. Their photo-response and thermal bleaching kinetics were detailed investigated by UV absorption spectra. The results showed that the time constants were higher than that of our previously reported compounds at least one order of magnitude and the rate constants of the as-synthesized compounds were significantly influenced by the size and electronegativity of different halogen atoms. The fluorescence emission were modulated in a high degree via photoisomerization of pyrazolones, which might be due to the efficient energy transfer from E-form to K-form isomers for their partly overlaps between their E-form absorption spectra and K-form fluorescence spectra.
      Graphical abstract image

      PubDate: 2016-08-11T11:47:45Z
       
  • Structural transformation of synthetic hydroxyapatite under simulated in
           vivo conditions studied with ATR-FTIR spectroscopic imaging
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Anna Sroka-Bartnicka, Leszek Borkowski, Grazyna Ginalska, Anna Ślósarczyk, Sergei G. Kazarian
      Hydroxyapatite and carbonate-substituted hydroxyapatite are widely used in bone tissue engineering and regenerative medicine. Both apatite materials were embedded into recently developed ceramic/polymer composites, subjected to Simulated Body Fluid (SBF) for 30days and characterized using ATR-FTIR spectroscopic imaging to assess their behaviour and structures. The specific aim was to detect the transition phases between both types of hydroxyapatite during the test and to analyze the surface modification caused by SBF. ATR-FTIR spectroscopic imaging was successfully applied to characterise changes in the hydroxyapatite lattice due to the elastic properties of the scaffolds. It was observed that SBF treatment caused a replacement of phosphates in the lattice of non-substituted hydroxyapatite by carbonate ions. A detailed study excluded the formation of pure A type carbonate apatite. In turn, CO3 2– content in synthetic carbonate-substituted hydroxyapatite decreased. The usefulness of ATR-FTIR spectroscopic imaging studies in the evaluation of elastic and porous β-glucan hydroxyapatite composites has been demonstrated.
      Graphical abstract image

      PubDate: 2016-08-11T11:47:45Z
       
  • Optical analysis of samarium doped sodium bismuth silicate glass
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): V. Thomas, R.G.S. Sofin, M. Allen, H. Thomas, P.R. Biju, G. Jose, N.V. Unnikrishnan
      Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV–Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3+‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices.
      Graphical abstract image

      PubDate: 2016-08-11T11:47:45Z
       
  • Photoluminescence properties and thermal stability of blue-emitting
           Ba5−xCl(PO4)3:xEu2+ (0.004≤x≤0.016) phosphors
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Jie Liu, Zhi-Ming Zhang, Zhan-Chao Wu, Fang-Fang Wang, Zhen-Jiang Li, Shao-Ping Kuang, Ming-Mei Wu
      A series of blue-emitting Ba5− x Cl(PO4)3:xEu2+ (0.004≤ x ≤0.016) phosphors were synthesized by conventional high-temperature solid state reaction. The structure and photoluminescence (PL) properties of the phosphors were investigated. The as-prepared phosphors exhibit broad excitation band ranging from 250 to 420nm, and strong asymmetric blue emission band peaking at 436nm. The optimum concentration of Eu2+ in the Ba5Cl(PO4)3:Eu2+ phosphor is x =0.01, and the concentration quenching mechanism is verified to be the combined actions of dipole-dipole interaction and radiation re-absorption mechanism. The thermal stability of Ba5Cl(PO4)3:Eu2+ was evaluated by temperature-dependent PL spectra. Compared with that of commercial BaMgAl10O17:Eu2+ (BAM) phosphor, the Ba5− x Cl(PO4)3:xEu2+ phosphors exhibit similarly excellent thermal quenching property. In addition, the CIE chromaticity coordinates of Ba5− x Cl(PO4)3:xEu2+ (0.004≤ x ≤0.016) were calculated to evaluate the color quality. All the results indicate that Ba5Cl(PO4)3:Eu2+ is a promising candidate phosphor for near-ultraviolet (n-UV) pumped LED.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • One step effective removal of Congo Red in chitosan nanoparticles by
           encapsulation
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Erol Alver, Mehmet Bulut, Ayşegül Ülkü Metin, Hakan Çiftçi
      Chitosan nanoparticles (CNPs) were prepared with ionotropic gelation between chitosan and tripolyphosphate for the removal of Congo Red. The production of chitosan nanoparticles and the dye removal process was carried out in one-step. The removal efficiency of Congo Red by encapsulation within chitosan from the aqueous solution and its storage stability are examined at different pH values. The influence of some parameters such as the initial dye concentration, pH value of the dye solution, electrolyte concentration, tripolyphosphate concentration, mixing time and speed on the encapsulation is examined. Congo Red removal efficiency and encapsulation capacity of chitosan nanoparticles were determined as above 98% and 5107mg Congo Red/g chitosan, respectively.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • Investigation of fluorescence methods for rapid detection of municipal
           wastewater impact on drinking water sources
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Nicolas M. Peleato, Raymond L. Legge, Robert C. Andrews
      Fluorescence spectroscopy as a means to detect low levels of treated wastewater impact on two source waters was investigated using effluents from five wastewater facilities. To identify how best to interpret the fluorescence excitation-emission matrices (EEMs) for detecting the presence of wastewater, several feature selection and classification methods were compared. An expert supervised regional integration approach was used based on previously identified features which distinguish biologically processed organic matter including protein-like fluorescence and the ratio of protein to humic-like fluorescence. Use of nicotinamide adenine dinucleotide-like (NADH) fluorescence was found to result in higher linear correlations for low levels of wastewater presence. Parallel factors analysis (PARAFAC) was also applied to contrast an unsupervised multiway approach to identify underlying fluorescing components. A humic-like component attributed to reduced semiquinone-like structures was found to best correlate with wastewater presence. These fluorescent features were used to classify, by volume, low (0.1–0.5%), medium (1–2%), and high (5–15%) levels by applying support vector machines (SVMs) and logistic regression. The ability of SVMs to utilize high-dimensional input data without prior feature selection was demonstrated through their performance when considering full unprocessed EEMs (66.7% accuracy). The observed high classification accuracies are encouraging when considering implementation of fluorescence spectroscopy as a water quality monitoring tool. Furthermore, the use of SVMs for classification of fluorescence data presents itself as a promising novel approach by directly utilizing the high-dimensional EEMs.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • Etchant-based design of gold tip apexes for plasmon-enhanced Raman
           spectromicroscopy
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Sergey Kharintsev, Alexander Alekseev, Joachim Loos
      In this paper, we gain insight into the design and optimization of plasmonic (metallic) tips prepared with dc-pulsed voltage electrochemical etching gold wires, provided that, a duty cycle is self-tuned. Physically, it means that etching electrolyte attacks the gold wire equally for all pulse lengths, regardless of its surface shape. Etchant effect on the reproducibility of a curvature radius of the tip apex is demonstrated. It means that the gold conical tips can be designed chemically with a choice of proper etchant electrolyte. It is suggested to use a microtomed binary polymer blend consisting of polyamide and low density polyethylene, as a calibration grating, for optimizing and standardizing tip-enhanced Raman scattering performance.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • A combined spectroscopic and TDDFT study of natural dyes extracted from
           fruit peels of Citrus reticulata and Musa acuminata for dye-sensitized
           solar cells
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Eka Cahya Prima, Novianto Nur Hidayat, Brian Yuliarto, Suyatman, Hermawan Kresno Dipojono
      This study reports the novel spectroscopic investigations and enhanced the electron transfers of Citrus reticulata and Musa acuminata fruit peels as the photosensitizers for the dye-sensitized solar cells. The calculated TD-DFT-UB3LYP/6-31+G(d,p)-IEFPCM(UAKS), experiment spectra of ultra-violet–visible spectroscopy, and Fourier transform infrared spectroscopy studies indicate the main flavonoid (hesperidin and gallocatechin) structures of the dye extracts. The optimized flavonoid structures are calculated using Density functional theory (DFT) at 6-31+G(d,p) level. The rutinosyl group of the hesperidin pigment (Citrus reticulata) will be further investigated compared to the gallocatechin (Musa acuminata) pigment. The acidity of the dye extract is treated by adding 2% acetic acid. The energy levels of the HOMO-LUMO dyes are measured by a combined Tauc plot and cyclic voltammetry contrasted with the DFT data. The electrochemical impedance spectroscopy will be performed to model the dye electron transfer. As for the rutinosyl group presence and the acidic treatment, the acidified Citrus reticulata cell under continuous light exposure of 100mW·cm−2 yields a short-circuit current density (J sc ) of 3.23mA/cm2, a photovoltage (Voc) of 0.48V, and a fill factor of 0.45 corresponding to an energy conversion efficiency (η) of 0.71% because the shifting down HOMO-LUMO edges and the broadening dye's absorbance evaluated by a combined spectroscopic and TD-DFT method. The result also leads to the longest diffusion length of 32.2μm, the fastest electron transit of 0.22ms, and the longest electron lifetime of 4.29ms.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • Quinazolinone derivative: Model compound for determination of dipole
           moment, solvatochromism and metal ion sensing
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Abdullah G. Al-Sehemi, Mehboobali Pannipara, Abul Kalam
      A dihydroquinazolinone derivative 2-(2,4-Dimethoxy-phenyl)-2,3-dihydro-1H-quinazolin-4-one (1) was synthesized and characterized by 1H NMR, 13C NMR and FT-IR and its spectral, photophysical, intramolecular charge transfer characteristics were studied by absorption and emission spectroscopy. The compound exhibits significant changes in their photophysical properties depending on the solvent polarity. The observed bathochromic emission band and difference in Stokes shift on changing the polarity of the solvents clearly demonstrate the highly polar character of the excited state, which is also supported by the enhancement of dipole moment of the molecule upon photoexcitation. Solvatochromic shift methods based on Lippert–Mataga, Bakhshiev-Kawski and Reichardt's correlations were applied to calculate the ground, excited and change in dipole moments. The effect of solute–solvent interactions on compound 1 was studied using multi-parameter solvent polarity scales proposed by Kamlet–Taft and Catalan. The interactions of various metal ions on compound 1 were also studied using steady state fluorescence measurements. The emission profile reveals that it acts as on-off type fluorescent chemosensor for selective and sensitive detection of Hg2+ ions. Complexation stoichiometry and mechanism of quenching were determined from Benesi–Hildebrand and Stern-Volmer plot.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • Biophysical influence of coumarin 35 on bovine serum albumin:
           Spectroscopic study
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Tuğba Bayraktutan, Yavuz Onganer
      The binding mechanism and protein–fluorescence probe interactions between bovine serum albumin (BSA) and coumarin 35 (C35) was investigated by using UV–Vis absorption and fluorescence spectroscopies since they remain major research topics in biophysics. The spectroscopic data indicated that a fluorescence quenching process for BSA–C35 system was occurred. The fluorescence quenching processes were analyzed using Stern-Volmer method. In this regard, Stern-Volmer quenching constants (KSV) and binding constants were calculated at different temperatures. The distance r between BSA (donor) and C35 (acceptor) was determined by exploiting fluorescence resonance energy transfer (FRET) method. Synchronous fluorescence spectra were also studied to observe information about conformational changes. Moreover, thermodynamics parameters were calculated for better understanding of interactions and conformational changes of the system.
      Graphical abstract image

      PubDate: 2016-08-06T11:23:55Z
       
  • High wavenumber Raman spectroscopy in the characterization of urinary
           metabolites of normal subjects, oral premalignant and malignant patients
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Elumalai Brindha, Ramu Rajasekaran, Prakasarao Aruna, Dornadula Koteeswaran, Singaravelu Ganesan
      Urine has emerged as one of the diagnostically potential bio fluids, as it has many metabolites. As the concentration and the physiochemical properties of the urinary metabolites may vary under pathological transformation, Raman spectroscopic characterization of urine has been exploited as a significant tool in identifying several diseased conditions, including cancers. In the present study, an attempt was made to study the high wavenumber (HWVN) Raman spectroscopic characterization of urine samples of normal subjects, oral premalignant and malignant patients. It is concluded that the urinary metabolites flavoproteins, tryptophan and phenylalanine are responsible for the observed spectral variations between the normal and abnormal groups. Principal component analysis-based linear discriminant analysis was carried out to verify the diagnostic potentiality of the present technique. The discriminant analysis performed across normal and oral premalignant subjects classifies 95.6% of the original and 94.9% of the cross-validated grouped cases correctly. In the second analysis performed across normal and oral malignant groups, the accuracy of the original and cross-validated grouped cases was 96.4% and 92.1% respectively. Similarly, the third analysis performed across three groups, normal, oral premalignant and malignant groups, classifies 93.3% and 91.2% of the original and cross-validated grouped cases correctly.
      Graphical abstract image

      PubDate: 2016-08-01T10:46:03Z
       
  • Data fusion of near-infrared and mid-infrared spectra for identification
           of rhubarb
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Wenjuan Sun, Xin Zhang, Zhuoyong Zhang, Ruohua Zhu
      Rhubarb has different medicinal efficacy to official rhubarb and may affect the clinical medication safety. In order to guarantee the quality of rhubarb, we established a method to distinguish unofficial rhubarbs. 52 official and unofficial rhubarb samples were analyzed using near-infrared (NIR) spectroscopy and mid-infrared (MIR) spectroscopy for classification. The feature vectors, which were selected by wavelet compression (WC) and interval partial least squares (iPLS) from NIR, MIR spectra, were fused together for identifying rhubarb samples. Partial least squares-discriminant analysis (PLS-DA), soft independent modeling of class analogies (SIMCA), support vector machine (SVM) and artificial neural network (ANN) were compared for classifying rhubarb. The use of data fusion strategies improved the classification model and allowed correct classification of all the samples.
      Graphical abstract image

      PubDate: 2016-08-01T10:46:03Z
       
  • Dimers or trimers? A characterization of the halogen bonded complexes of
           CF3X (X=I or Br) with dimethyl ether and acetone in cryosolutions
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Liene I. De Beuckeleer, Wouter A. Herrebout
      Acetone molecules dissolved in liquid krypton are inclined to self-associate into dimers. This behavior affects its use as a prototype Lewis base in studies of weak intermolecular interactions. In this study infrared spectra of mixed solutions of dimethyl ether and CF3X and of acetone and CF3X (with X=I or Br) dissolved in liquid argon and liquid krypton are recorded at constant temperature. The dataset for dimethyl ether is used to validate a numerical method based on least-squares fitting of a model including contributions of both monomers and a heterodimer with 1:1 stoichiometry. The resulting monomer and dimer spectra show excellent agreement with previous studies found in literature. The analysis of the dataset for acetone requires an extension of the model with contributions for the acetone homodimer and for (acetone)2·CF3X and acetone·(CF3X)2 trimers. The results show that many signals for acetone·CF3I and (acetone)2·CF3I are observed, while only a few bands due to acetone·(CF3I)2 occur. The use of numerical approaches adjusted to the specificities of a mixture of two compounds allows to reliably resolve overlapping spectra of monomers and heterocomplexes and characterizing heterocomplex features that could not be deduced using earlier methods. To support the assignments made, ab initio calculations predicting geometries, relative stabilities and harmonic vibrational frequencies for the species envisaged are performed.
      Graphical abstract image

      PubDate: 2016-08-01T10:46:03Z
       
  • Impact of Fe on structural modification and room temperature magnetic
           ordering in BaTiO3
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Soumya Rajan, P.M. Mohammed Gazzali, G. Chandrasekaran
      Ba1− x Fe x TiO3 (x =0, 0.005, 0.01) polycrystalline ceramics are prepared using solid state reaction method. Structural studies through XRD, Raman and XPS confirm single tetragonal phase for BaTiO3 whereas a structural disorder tends to intervene with the introduction of smaller Fe ions which reduces the tolerance factor and tetragonality ratio. Grain size of the samples is estimated using SEM micrographs with ImageJ software and chemical composition is confirmed using EDX spectra. Raman spectra measured in the temperature range of 303K to 573K showers light on the structural phase transition exploiting a significant disappearance of the 306cm−1 mode. Further, structural analyses suggest the entry of Fe into the B-site upon increasing its concentration in BaTiO3. The dopant sensitive modes lying at around 640cm−1 and 650cm−1 are assigned to lattice strain. A reduction in ferroelectric to paraelectric transition temperature is observed with a transformation from diffused type to normal ferroelectric upon the increased Fe content. The oxidation state of Fe in the BaTiO3 lattice has been decided using EPR Spectra precisely. Room temperature magnetic ordering is observed in Fe substituted BaTiO3 using PPMS. The coexistence of ferroelectric and magnetic ordering is established in the present study for optimized Fe substituted BaTiO3.
      Graphical abstract image

      PubDate: 2016-08-01T10:46:03Z
       
  • Raman spectroscopy detection of biomolecules in biocrusts from differing
           environmental conditions
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): I. Miralles, S.E. Jorge-Villar, B. van Wesemael, R. Lázaro
      Lichens and cyanobacteria colonize inhospitable places covering a wide climate range due to their different survival strategies, such as the synthesis of protective biomolecules. The effect of ecological factors on the synthesis of biomolecules has not been widely analysed. This study aimed to assess the effects of four factors (species, microclimate, seasonality and hydration state) and their interactions on the biomolecule frequency detected by Raman Spectroscopy. We included cyanobacterial biocrusts, and the lichens Diploschistes diacapsis, Squamarina lentigera, and Lepraria isidiata; two contrasted microclimates (typical and marginal), two contrasted seasons (hot and dry vs cool and wet) and two hydration states (dry and wet). “Species” was the most influential factor in the identity and frequency of the main biomolecules. Microclimatic differences in the range of the local specific habitats only influenced the biomolecules in cyanobacteria. There was a quadruple interaction among the factors, the effects being different mainly depending on the species. At D. diacapsis, the production of their main biomolecules depended on microclimate, although it also depended on seasonality. Nevertheless, in L. isidiata and S. lentigera microclimatic differences did not significantly affect the production of biomolecules. In the lichen species, the microhabitats exposed to relatively larger incident radiation did not show significantly larger relative frequency of photoprotective biomolecules. No clear connection between higher production of oxalates and drier microhabitats was found, suggesting that the synthesis of oxalates is not related to water reserve strategy. The pros and cons of monitor biomolecules in biocrust by Raman spectrometry were also discussed.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Molecular characteristics of a fluorescent chemosensor for the recognition
           of ferric ion based on photoresponsive azobenzene derivative
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Zhen Chi, Xia Ran, Lili Shi, Jie Lou, Yanmin Kuang, Lijun Guo
      Metal ion recognition is of great significance in biological and environmental detection. So far, there is very few research related to the ferric ion sensing based on photoresponsive azobenzene derivatives. In this work, we report a highly selective fluorescent “turn-off” sensor for Fe3+ ions and the molecular sensing characteristics based on an azobenzene derivative, N-(3,4,5-octanoxyphenyl)-N′-4-[(4-hydroxyphenyl)azophenyl]1,3,4-oxadiazole (AOB-t8). The binding association constant was determined to be 6.07×103 M−1 in ethanol and the stoichiometry ratio of 2:2 was obtained from Job's plot and MS spectra. The AOB-t8 might be likely to form the dimer structure through the chelation of ferric ion with the azobenzene moiety. Meanwhile, it was found that the photoisomerization property of AOB-t8 was regulated by the binding with Fe3+. With the chelation of Fe3+, the regulated molecular rigidity and the perturbed of electronic state and molecular geometry was suggested to be responsible for the accelerated isomerization of AOB-t8 to UV irradiation and the increased fluorescence lifetime of both trans- and cis-AOB-t8-Fe(III). Moreover, the reversible sensing of AOB-t8 was successfully observed by releasing the iron ion from AOB-t8-Fe(III) with the addition of citric acid.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Environment effect on spectral and charge distribution characteristics of
           some drugs of folate derivatives
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): M. Khadem Sadigh, M.S. Zakerhamidi, S.M. Seyed Ahmadian, M. Johari-Ahar, L. Zare Haghighi
      Molecular surrounding media as an important factor can effect on the operation of wide variety of drugs. For more study in this paper, spectral properties of Methotrexate and Folinic acid have been studied in various solvents. Our results show that the photo-physical of solute molecules depend strongly on solute-solvent interactions and active groups in their chemical structures. In order to investigate the contribution of specific and nonspecific interactions on the various properties of drug molecules, the linear solvation energy relationships concept is used. Moreover, charge distribution characteristics of used samples with various resonance structures in solvent environments were calculated by means of solvatochromic method. The high value of dipole moments in excited state show that local intramolecular charge transfer can occur by excitation. These results about molecular interactions can be extended to biological systems and can indicate completely the behaviors of Methotrexate and Folinic acid in polar solvents such as water in body system.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Cu(I) complexes of bis(methyl)(thia/selena) salen ligands: Synthesis,
           characterization, redox behavior and DNA binding studies
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Ashish K. Asatkar, Mamta Tripathi, Snigdha Panda, Rama Pande, Sanjio S. Zade
      Mononuclear cuprous complexes 1 and 2, [{CH3E(o-C6H4)CH=NCH2}2Cu]ClO4; E=S/Se, have been synthesized by the reaction of bis(methyl)(thia/selena) salen ligands and [Cu(CH3CN)4]ClO4. Both the products were characterized by elemental analysis, ESI-MS, FT-IR, 1H/13C/77Se NMR, and cyclic voltammetry. The complexes possess tetrahedral geometry around metal center with the N2S2/N2Se2 coordination core. Cyclic voltammograms of complexes 1 and 2 displayed reversible anodic waves at E 1/2 =+0.08V and +0.10V, respectively, corresponding to the Cu(I)/Cu(II) redox couple. DNA binding studies of both the complexes were performed applying absorbance, fluorescence and molecular docking techniques. Competitive binding experiment of complexes with ct-DNA against ethidium bromide is performed to predict the mode of binding. The results indicate the groove binding mode of complexes 1 and 2 to DNA. The binding constants revealed the strong binding affinity of complexes towards ct-DNA.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Raman spectral characteristics of magmatic-contact metamorphic coals from
           Huainan Coalfield, China
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): Shancheng Chen, Dun Wu, Guijian Liu, Ruoyu Sun
      Normal burial metamorphism of coal superimposed by magmatic-contact metamorphism makes the characteristics of the Raman spectrum of coal changed. Nine coal samples were chosen at a coal transect perpendicular to the intrusive dike, at the No. 3 coal seam, Zhuji Coal Mine, Huainan Coalfield, China, with different distances from dike-coal boundary (DCB). Geochemical (proximate and ultimate) analysis and mean random vitrinite reflectance (R 0, %) indicate that there is a significant relationship between the values of volatile matter and R 0 in metamorphosed coals. Raman spectra show that the graphite band (G band) becomes the major band but the disordered band (D band) disappears progressively, with the increase of metamorphic temperature in coals, showing that the structural organization in high-rank contact-metamorphosed coals is close to that of well-crystallized graphite. Evident relationships are observed between the calculated Raman spectral parameters and the peak metamorphic temperature, suggesting some spectral parameters have the potentials to be used as geothermometers for contact-metamorphic coals.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Fluorescent probes based on side-chain chlorinated benzo[a]phenoxazinium
           chlorides: Studies of interaction with DNA
    • Abstract: Publication date: 15 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 171
      Author(s): B. Rama Raju, M. Sameiro T. Gonçalves, Paulo J.G. Coutinho
      The interaction of DNA with six water soluble benzo[a]phenoxazinium chlorides mono- or di-substituted with 3-chloropropyl groups at the O and N of 2- and 9-positions, along with methyl, hydroxyl and amine terminal groups at 5-positions, was investigated by photophysical techniques. The results indicated that almost all compounds intercalated in DNA base pairs at phosphate to dye ratio higher than 5. At lower values of this ratio, electrostatic binding mode with DNA was observed. Groove binding was detected mainly for the benzo[a]phenoxazinium dye with NH2·HBr terminal. The set of six benzo[a]phenoxazinium chlorides proved successful to label the migrating DNA in agarose gel electrophoresis assays. These finding proves the ability of these benzo[a]phenoxazinium dyes to strongly interact with DNA.
      Graphical abstract image

      PubDate: 2016-07-27T09:19:09Z
       
  • Design and synthesis of a new organic receptor and evaluation of
           colorimetric anion sensing ability in organo-aqueous medium
    • Abstract: Publication date: 5 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 170
      Author(s): P. Srikala, Kartick Tarafder, Darshak R. Trivedi
      A new organic receptor has been designed and synthesized by the combination of aromatic dialdehyde with nitro-substituted aminophenol resulting in a Schiff base compound. The receptor exhibited a colorimetric response for F− and AcO− ion with a distinct color change from pale yellow to red and pink respectively in dry DMSO solvent and yellow to pale greenish yellow in DMSO:H2O (9:1, v/v). UV–Vis titration studies displayed a significant shift in absorption maxima in comparison with the free receptor. The shift could be attributed to the hydrogen bonding interactions between the active anions and the hydroxyl functionality aided by the electron withdrawing nitro substituent on the receptor. 1H NMR titration and density functionality studies have been performed to understand the nature of interaction of receptor and anions. The lower detection limit of 1.12ppm was obtained in organic media for F− ion confirming the real time application of the receptor.
      Graphical abstract image

      PubDate: 2016-07-14T13:53:29Z
       
  • Overall uncertainty measurement for near infrared analysis of
           cryptotanshinone in tanshinone extract
    • Abstract: Publication date: 5 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 170
      Author(s): Zhong Xue, Bing Xu, Xinyuan Shi, Chan Yang, Xianglong Cui, Gan Luo, Yanjiang Qiao
      This study presented a new strategy of overall uncertainty measurement for near infrared (NIR) quantitative analysis of cryptotanshinone in tanshinone extract powders. The overall uncertainty of NIR analysis from validation data of precision, trueness and robustness study was fully investigated and discussed. Quality by design (QbD) elements, such as risk assessment and design of experiment (DOE) were utilized to organize the validation data. An “I × J × K” (series I, the number of repetitions J and level of concentrations K) full factorial design was used to calculate uncertainty from the precision and trueness data. And a 27–4 Plackett–Burmann matrix with four different influence factors resulted from the failure mode and effect analysis (FMEA) analysis was adapted for the robustness study. The overall uncertainty profile was introduced as a graphical decision making tool to evaluate the validity of NIR method over the predefined concentration range. In comparison with the T. Saffaj's method (Analyst, 2013, 138, 4677.) for overall uncertainty assessment, the proposed approach gave almost the same results, demonstrating that the proposed method was reasonable and valid. Moreover, the proposed method can help identify critical factors that influence the NIR prediction performance, which could be used for further optimization of the NIR analytical procedures in routine use.
      Graphical abstract image

      PubDate: 2016-07-14T13:53:29Z
       
  • Applying graphene oxide nano-film over a polycarbonate nanoporous membrane
           to monitor E. coli by infrared spectroscopy
    • Abstract: Publication date: 5 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 170
      Author(s): Krishna Pal Singh, Neeraj Singh Dhek, Anuj Nehra, Sweeti Ahlawat, Anu Puri
      Nano-biosensors are excellent monitoring tools for rapid, specific, sensitive, inexpensive, in-field, on-line, and/or real-time detection of pathogens in foods, soil, air, and water samples. A variety of nano-materials (metallic, polymeric, and/or carbon-based) were employed to enhance the efficacy, efficiency, and sensitivity of these nano-biosensors, including graphene-based materials, especially graphene oxide (GO)-based materials. GO bears many oxygen-bearing groups, enabling ligand conjugation at the high density critical for sensitive detection. We have fabricated GO-modified nano-porous polycarbonate track-etched (PCTE) membranes that were conjugated to an Escherichia coli-specific antibody (Ab) and used to detect E. coli. The random distribution of nanopores on the PCTE membrane surface and the bright coating of the GO onto the membrane were confirmed by scanning electron microscope. Anti-E. coli β-gal Abs were conjugated to the GO surface via 1-ethyl-3,3-dimethylaminopropyl carbodiimide hydrochloride–N-hydroxysuccinimide chemistry; antibody coating was confirmed by the presence of a characteristic IR peak near 1600cm−1. A non-corresponding Ab (anti-Pseudomonas) was used as a negative control under identical conditions. When E. coli interacted anti-E.coli β-gal with Ab-coated GO-nano-biosensor units, we observed a clear shift in the IR peak from 3373.14 to 3315cm−1; in contrast, we did not observe any shift in IR peaks when the GO unit was coated with the non-corresponding Ab (anti-Pseudomonas). Therefore, the detection of E. coli using the described GO-nano-sensor unit is highly specific, is highly selective and can be applied for real-time monitoring of E. coli with a detection limit between 100μg/mL and 10μg/mL, similar to existing detection systems.
      Graphical abstract image

      PubDate: 2016-07-09T00:52:27Z
       
  • Fourier transform infrared spectroscopy and chemometrics for the
           characterization and discrimination of writing/photocopier paper types:
           Application in forensic document examinations
    • Abstract: Publication date: 5 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 170
      Author(s): Raj Kumar, Vinay Kumar, Vishal Sharma
      The aim of the present work is to explore the non-destructive application of ATR-FTIR technique for characterization and discrimination of paper samples which could be helpful to give forensic aid in resolving legal cases. Twenty-four types of paper brands were purchased from local market in and around Chandigarh, India. All the paper samples were subjected to ATR-FTIR analysis from 400 to 4000cm−1 wavenumber range. The qualitative feature and Chemometrics of the obtained spectral data are used for characterization and discrimination. Characterization is achieved by matching the peaks with standards of cellulose and inorganic fillers, a usual constituents of paper. Three different regions of IR, i.e. 400–2000cm−1, 2000–4000cm−1 and 400–4000cm−1 were selected for differentiation by Chemometrics analysis. The discrimination is achieved on the basis of three principal components, i.e. PC 1, PC 2 and PC 3. It is observed that maximum discrimination was procured in the wave number range of i.e. 2000–4000cm−1. Discriminating power was calculated on the basis of qualitative features as well, and it is found that the discrimination of paper samples was better achieved by Chemometrics analysis rather than qualitative features. The discriminating power by Chemometrics is 99.64% and which is larger as ever achieved by any group for present number of samples. The present result confirms that this study will be highly useful in forensic document examination work in the legal cases, where the authenticity of the document is challenged. The results are completely analytical and, therefore, overcome the problem encounter in traditional routine light/radiation scanning methods which are still in practice by various questioned document laboratories.
      Graphical abstract image

      PubDate: 2016-07-09T00:52:27Z
       
  • Spectroscopic study of 3-Hydroxyflavone - protein interaction in lipidic
           bi-layers immobilized on silver nanoparticles
    • Abstract: Publication date: 5 January 2017
      Source:Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 170
      Author(s): Mariana Voicescu, Sorana Ionescu, Cristina L. Nistor
      The interaction of 3-Hydroxyflavone with serum proteins (BSA and HSA) in lecithin lipidic bi-layers (PC) immobilized on silver nanoparticles (SNPs), was studied by fluorescence and Raman spectroscopy. BSA secondary structure was quantified with a deconvolution algorithm, showing a decrease in α-helix structure when lipids were added to the solution. The effect of temperature on the rate of the excited-state intra-molecular proton transfer and on the dual fluorescence emission of 3-HF in the HSA/PC/SNPs systems was discussed. Evaluation of the antioxidant activity of 3-HF in HSA/PC/SNPs systems was also studied. The antioxidant activity of 3-HF decreased in the presence of SNPs. The results are discussed with relevance to the secondary structure of proteins and of the 3-HF based nano-systems to a topical formulation useful in the oxidative stress process.
      Graphical abstract image

      PubDate: 2016-07-04T04:18:57Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.198.14.214
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016