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Journal Cover Photochemistry and Photobiology
  [SJR: 0.764]   [H-I: 96]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0031-8655 - ISSN (Online) 1751-1097
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Reduced Levels of Tissue Inhibitors of Metalloproteinases (TIMPs) in UVB
           Irradiated Corneal Epithelium
    • Abstract: Tissue inhibitors of metalloproteinases (TIMPs) are the major endogenous regulators of metalloproteinase activity in tissues. TIMPs are able to inhibit activity of all known matrix metalloproteinases (MMPs) and thus participate in controlling extracellular matrix synthesis and degradation. We showed previously elevated expressions of MMPs in the rabbit corneal epithelium upon UVB exposure and suggested that these enzymes might be involved in corneal destruction caused by excessive proteolysis. The aim of this study was to investigate TIMPs in the corneal epithelium after UV irradiation using immunohistochemical and biochemical methods. We found that as compared to control rabbit corneas where relatively high levels of TIMPs were present in the epithelium, repeated irradiation of the cornea with UVB rays (not with UVA rays of similar doses) significantly decreased TIMPs in corneal epithelial cells. The results of this study point to the suggestion that the decrease of TIMPs in the corneal epithelium after UVB irradiation contributes to increased proteolytic activity of MMPs in UVB irradiated corneal epithelium found previously. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T02:25:26.941082-05:
      DOI: 10.1111/php.12612
       
  • Selective Photoreceptor Gene Knock‐out Reveals a Regulatory Role for
           the Growth Behavior of Pseudomonas syringae
    • Abstract: The plant pathogen Pseudomonas syringae (Ps) is a well‐established model organism for bacterial infection of plants. The genome sequence of two pathovars, pv. syringae and pv. tomato, revealed one gene encoding a blue‐ and two genes encoding red/far red light sensing photoreceptors. Continuing former molecular characterization of the photoreceptor proteins, we here report selective photoreceptor gene disruption for pv. tomato aiming at identification of potentially regulatory functions of these photoreceptors. Transformation of Ps cells with linear DNA constructs yielded interposon mutations of the corresponding genes. Cell growth studies of the generated photoreceptor knock‐out mutants revealed their role in light‐dependent regulation of cell growth and motility. Disruption of the blue‐light (BL) receptor gene caused a growth deregulation, in line with an observed increased virulence of this mutant (Moriconi et al., Plant J., 2013, 76, 322). Bacterial phytochrome‐1 (BphP1) deletion mutant caused unaltered cell growth, but a stronger swarming capacity. Inactivation of its ortholog, BphP2, however, caused reduced growth and remarkably altered dendritic swarming behavior. Combined knock‐out of both bacteriophytochromes reproduced the swarming pattern observed for the BphP2 mutant alone. A triple knock out mutant showed a growth rate between that of the BL (deregulation) and the phytochrome‐2 mutant (growth reduction). This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-11T08:15:29.028773-05:
      DOI: 10.1111/php.12610
       
  • Identification of a Fluorescent Protein from Rhacostoma atlantica
    • Authors: Michael R. Tota; Jeanna M. Allen, Jan O. Karolin, Chris D. Geddes, William W.Ward
      Abstract: We have cloned a novel fluorescent protein from the jellyfish Rhacostoma atlantica. The closest known related fluorescent protein is the Phialidium yellow‐fluorescent protein, with only a 55% amino acid sequence identity. A somewhat unusual alanine‐tyrosine‐glycine amino acid sequence forms the presumed chromophore of the novel protein. The protein has an absorption peak at 466 nm and a fluorescence emission peak at 498 nm. The fluorescence quantum yield was measured to be 0.77 and the extinction coefficient is 58,200 M−1 cm−1. Several mutations were identified that shift the absorption peak to about 494 nm and the emission peak to between 512 and 514 nm. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-11T08:15:25.856241-05:
      DOI: 10.1111/php.12609
       
  • Peroxyoxalate High Energy Intermediate is Efficiently Decomposed by the
           Catalyst Imidazole
    • Authors: Andreia Boaro; Fernando Heering Bartoloni
      Abstract: The peroxyoxalate reaction is a highly efficient chemiluminescence system, its chemiexcitation process involving the intermolecular interaction between an activator (ACT) and the High Energy Intermediate (HEI) of the reaction. Typically, the HEI is generated through the reaction of an oxalate ester with H2O2, on the presence of a basic/nucleophilic catalyst, such as imidazole (IMI‐H). IMI‐H, besides of catalysing the formation of the HEI, is also known to decompose this peroxidic intermediate. Despite of that, up to now no rate constant value has been determined for such significant interaction. Through kinetic measurements, we have observed that IMI‐H is roughly four times more efficient than 9,10‐diphenylanthracene (DPA), a classic ACT, in catalysing the decomposition of the HEI by a bimolecular electron transfer reaction through a CIEEL‐like process. For instance, when IMI‐H and DPA are at the same concentration, 78% of the generated HEI is actually consumed by the non‐emissive bimolecular interaction with IMI‐H. We have obtained an average singlet excited state formation quantum yield, at infinite ACT concentration, of (5.5 ± 0.5) × 10–2 E mol−1, determined at five different IMI‐H concentrations. This ultimately suggests that the yield of formation of HEI actually does not depend on the IMI‐H concentration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T09:51:44.660258-05:
      DOI: 10.1111/php.12608
       
  • Diffuse Reflectance Spectroscopy Versus Mexameter® MX18 Measurements
           of Melanin and Erythema in an African Population
    • Authors: Caradee Y Wright; Aletta E Karsten, Marcus Wilkes, Ann Singh, Johan du Plessis, Patricia N Albers, Petrus A Karsten
      Abstract: Melanin provides protection against excess exposure to solar ultraviolet radiation (UVR) and related adverse health effects. Diffuse Reflectance Spectroscopy (DRS) can be used to calculate cutaneous melanin and erythema, but this is complex and has been mostly used for light‐to‐medium pigmented skin. Handheld reflectance spectrophotometers, such as the Mexameter® MX18, can also be used. We compared DRS‐calculated melanin and erythema values with Mexameter melanin and erythema index values to understand how these techniques / measurements correlate in an African population of predominantly deeply‐pigmented skin. 503 participants comprised 68.5% self‐identified Black African, 9.9% Indian/Asian, 18.4% White and 2.9% Coloured. The majority of Black African (45%), Indian/Asian (34%) and Coloured (53%) participants self‐identified their skin as being ‘brown’. Measured melanin levels increased with darker self‐reported skin colour. DRS‐calculated and Mexameter melanin values demonstrated a positive correlation (Spearman rho=0.87, p
      PubDate: 2016-06-08T09:50:55.906246-05:
      DOI: 10.1111/php.12607
       
  • Red Light Treatment in an Axotomy Model of Neurodegeneration
    • Authors: Kathy Beirne; Malgorzata Rozanowska, Marcela Votruba
      Abstract: Red light has been shown to provide neuroprotective effects. Axotomising the optic nerve initiates retinal ganglion cell (RGC) degeneration, and an early marker of this is dendritic pruning. We hypothesised that 670 nm light can delay axotomy induced dendritic pruning in the retinal explant. To test this hypothesis, we monitored the effects of 670 nm light (radiant exposure of 31.7 J/cm2), on RGC dendritic pruning in retinal explants from C57BL/6J mice, at 40 minutes, 8 hours and 16 hours post axotomy. For sham‐treated retinae, area under the Sholl curve, peak of the Sholl curve and dendritic length at 8 hours post axotomy showed statistically significant reductions by 42.3% (p=0.008), 29.8% (p=0.007) and 38.4% (p=0.038), respectively, which were further reduced after 16 hours by 40.56% (p
      PubDate: 2016-06-08T09:45:24.669679-05:
      DOI: 10.1111/php.12606
       
  • Relative Contributions of UVB and UVA to the Photoconversion of
           (6‐4) Photoproducts into their Dewar Valence Isomers
    • Authors: Thierry Douki
      Abstract: Dewar valence isomers are photoisomerization products of pyrimidine (6‐4) pyrimidone photoproducts, a major class of UV‐induced DNA lesions which exhibits a maximal absorption around 320 nm. However, Dewar isomers are not produced in significant amounts in cells exposed to biologically relevant doses of UVB. In contrast, they are readily produced when cells are exposed to a combination of UVA and UVB. The present computational work demonstrates that, on the basis of known absorption properties and formation quantum yields, the difference in Dewar formation between the two types of radiation can be explained by the role of normal bases. In the UVB range, at the low level of (6‐4) photoproducts present in cells exposed to realistic doses, normal bases are present in overwhelming amounts and absorb the vast majority of the incident photons. In contrast, the absorption of DNA bases is much weaker in the UVA range while that of (6‐4) photoproducts is still significant, making photoisomerization possible. This two‐photon process makes it difficult to define an action spectrum for the formation of Dewar isomers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-08T00:19:32.174427-05:
      DOI: 10.1111/php.12605
       
  • Synthesis of TiO2/CNT Composites and its Photocatalytic Activity Towards
           Sudan (I) Degradation
    • Authors: Amat Miribangul; Xiaoli Ma, Chen Zeng, Huan Zou, Yahui Wu, Tengpeng Fan, Zhi Su
      Abstract: Semiconductor photocatalysis has the potential for achieving sustainable energy generation and degrading organic contaminants. In TiO2, the addition of carbonaceous nanomaterials has attracted extensive attention as a means to increase its photocatalytic activity. In this study, composites of TiO2 and carbon nanotubes (CNT) in various proportions were synthesized by the hydrothermal method. The crystalline structures, morphologies, and light absorption properties of the TiO2/CNT photocatalysts were characterized by PXRD, TEM, and UV‐Vis absorption spectra. The photocatalytic efficiency of the composites was evaluated by the degradation of Sudan (I) in UV‐Vis light. Introducing 0.1‐0.5 wt% CNT was shown to substantially improve the photoactivity of TiO2. The composite with 0.3 wt% CNT showed the best catalytic activity, and its reaction activation energy was calculated as 39.57 kJ/mol from experimental rates. The degradation products of Sudan (I) with different irradiation durations were characterized by Fourier transform infrared spectroscopy, and a degradation reaction process was proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:20:31.001256-05:
      DOI: 10.1111/php.12604
       
  • Albumin‐folate‐conjugates for Drug‐targeting in
           Photodynamic Therapy
    • Abstract: Photodynamic therapy (PDT) is based on the cytotoxicity of photosensitizers in the presence of light. Increased selectivity and effectivity of the treatment is expected if a specific uptake of the photosensitizers into the target cells, often tumor cells, can be achieved. An attractive transporter for that purpose is the folic acid receptor α (FRα), which is over‐expressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe the synthesis and photobiological characterization of polar β‐carboline derivatives as photosensitizers covalently linked to folate‐tagged albumin as carrier system. The particles were taken up by KB (human carcinoma) cells within < 90 min and then co‐localized with a lysosomal marker. FRα antibodies prevented the uptake and also the corresponding conjugate without folate was not taken up. Accordingly, a folate‐albumin‐β‐carbolinium conjugate proved to be phototoxic, while the corresponding albumin‐β‐carbolinium conjugates without FA were non‐toxic, both with and without irradiation. An excess of free folate as competitor for the FRα‐mediated uptake completely inhibited the photocytotoxicity. Interestingly, the albumin conjugates are devoid of photodynamic activity under cell‐free conditions, as shown for DNA as a target. Thus, phototoxiciy requires cellular uptake and lysosomal degradation of the conjugates. In conclusion, albumin‐folate‐conjugates appear to be promising vehicles for a tumor cell targeted PDT. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:15:30.749931-05:
      DOI: 10.1111/php.12602
       
  • Development of a Novel Covalent Folate‐Albumin‐Photosensitizer
           Conjugate
    • Authors: Simon Beaudoin; Jeffrey V. Leyton
      Abstract: There is considerable interest in the development of novel and more efficient delivery systems for improving the efficacy of photodynamic therapy (PDT). The authors in this highlighted issue describe the synthesis and the photobiological characterizations of two photosensitizer (PS) conjugates based on β‐carboline derivatives covalently conjugated to folic acid (FA) coupled to bovine serum albumin (BSA) as a carrier system specifically targeting cancer cells overexpressing FA receptor alpha (FRα). Accordingly, only the FA‐BSA‐β‐carboline conjugates are internalized specifically in FRα‐positive cells and are proved to be phototoxic. On the other hand, albumin‐β‐carboline conjugates without FA or β‐carboline derivatives alone are not internalized and non‐toxic. This conjugate is among the first to produce a conjugate composed of a PS and FA molecules that are directly conjugated to BSA. In addition, the in vitro studies are the first evidence that directly conjugated FA‐BSA can be used as carriers to selectively enhance cytotoxicity by PDT relative to unmodified PS or non‐targeted BSA‐PS. This strategy is a positive step forward for the covalent design and construction of a photodynamic nanomedicine for FR‐positive tumors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:12:41.713124-05:
      DOI: 10.1111/php.12603
       
  • Vibrationally Resolved Absorption and Fluorescence Spectra of Firefly
           Luciferin: A Theoretical Simulation in the Gas Phase and in Solution
    • Abstract: Firefly bioluminescence has been applied in several fields. However, the absorption and fluorescence spectra of the substrate, luciferin, have not been observed at the vibrational level. In the current study, the vibrationally resolved absorption and fluorescence spectra of firefly luciferin (neutral form LH2, phenolate‐ion form LH‐ and dianion form L2‐) are simulated using the density functional method and convoluted by a Gaussian function, with displacement, distortion and Duschinsky effects in the framework of the Franck‐Condon approximation. Both neutral and anionic forms of the luciferin are considered in the gas phase and in solution. The simulated spectra have desired band maxima with the experimental ones. The vibronic structure analysis reveals that the features of the most contributive vibrational modes coincide with the key geometry‐changing region during transition between the ground state and the first singlet excited state. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-10T23:25:44.518791-05:
      DOI: 10.1111/php.12601
       
  • Influence of Donor on the Sensing Performance of a Series of
           TBET‐based Two‐photon Fluorescent Cu2+ Probes
    • Abstract: Optical properties of a series of molecular two‐photon fluorescent Cu2+ probes containing the same acceptor (rhodamine group) are analyzed by using time‐dependent density functional theory in combination with analytical response theory. Special emphasis is placed on evolution of the probes’ optical properties in the presence of Cu2+. In this study, the compound with naphthalene as the donor is shown to be excellent ratiometric fluorescent chemosensor, while the compound with quinoline derivative as the donor shows off/on‐typed colorimetric fluorescent response. For the compound with naphthalimide derivative as the donor, changing the connection between the donor and acceptor can efficiently prevent the fluorescent quenching of the probe both in the absence and presence of Cu2+. The donor moiety and the connection between donor and acceptor are thus found to play dominant roles on sensing performance of these probes. Moreover, distributions of molecular orbitals involved in the excitation and emission of the probes are analyzed to explore responsive mechanism of the probes. The through‐bond energy transfer (TBET) process is theoretically demonstrated. Our results are used to elucidate the available experimental measurements. This work is helpful to understand the relationships of structure with optical properties for the studied probes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:44.915137-05:
      DOI: 10.1111/php.12597
       
  • Problems on the Evaluation of the Critical Wavelength of Sunscreens for
           “Broad Spectrum” Approval Brought on by Viscous Fingering
           During Sunscreen Application
    • Authors: Misaki Wakabayashi; Kunihiko Okano, Tsubasa Mukawa, Daisuke Maezawa, Hitoshi Masaki, Akihiro Kuroda, Kouichi Asakura
      Abstract: When a viscous liquid is applied to a solid substrate, a patterned liquid layer is usually formed by the phenomenon called viscous fingering, since the moving liquid surface is in far‐from‐equilibrium conditions to let the morphological fluctuation to grow. Pseudo‐sunscreen solutions were prepared and applied on a flat quartz plate. A spatially periodic stripe pattern was formed on the pseudo‐sunscreen layer when a block applicator was used, while a flat surface layer was formed when a four‐sided applicator was used. UV absorbance of the patterned layer was lower than that of the flat layer having the same average thickness. In addition, a larger decrease in the UV absorbance by the pattern formation was observed at wavelengths at which the UV absorbance of the flat layer was large, which was consistent with theoretical simulations. In 2011, US FDA introduced a new rule using the term “Broad Spectrum” for labeling the sunscreens. The different decrease in the UV absorbance at each wavelength was found to change the critical wavelength, which is a criterion for sunscreens to be labeled as “Broad Spectrum” protection. The result of this study made the problem on the evaluation of the critical wavelength came up to the surface. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:43.341754-05:
      DOI: 10.1111/php.12598
       
  • Regulation of Black Pepper Inflorescence Quantity by Shading at Different
           Growth Stages
    • Authors: Chao Zu; Guiping Wu, Zhigang Li, Jianfeng Yang, Can Wang, Huan Yu, Huasong Wu
      Abstract: Black pepper is a perennial plant that can bloom throughout the year. It is generally expected that pepper inflorescence quantity could be minimized at the non‐full bloom stage. The objective of this study was to find an appropriate shading measure that could inhibit blooming at other growing stages except the full‐bloom stage and did not cause any reduction of pepper yield and quality. In this study, pepper trees were shaded up to 15%, 30%, 60% and 75%, respectively, and the inflorescence quantity, photosynthetic characteristics, pepper yield and quality traits were investigated at every growing stage. The results showed that the effect of shading on pepper yield decreased as time progressed. Shading treatment did not alter the composition of piperine and volatile oil, but reduced the moisture content. Based on the correlation between photosynthetic parameter and inflorescence number, the appropriate shading intensities for regulating inflorescence quantity at different phenological stages were determined. Moreover, it was found that the regulation of inflorescence quantity could be achieved by controlling leaf temperature during recovery to filling period. This research outcome also will give us some guidelines to develop other management strategies that control leaf temperature and regulate inflorescence quantity to consequently improve pepper yield. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:34.4485-05:00
      DOI: 10.1111/php.12600
       
  • Chemiexcitation Efficiency of Intermolecular Electron‐transfer
           Catalyzed Peroxide Decomposition Shows Low Sensitivity to
           Solvent‐cavity Effects
    • Authors: Muhammad Khalid; Sergio P. de Souza, Fernando H. Bartoloni, Felipe A. Augusto, Wilhelm J. Baader
      Abstract: Intermolecular Chemically Initiated Electron Exchange Luminescence (CIEEL) systems are known to possess low chemiluminescence efficiency; whereas, the corresponding intramolecular transformations are highly efficient. As the reasons for this discrepancy are not known, we report in this work our studies of the solvent‐cavity effect on the efficiency of two intermolecular CIEEL systems, the catalyzed decomposition of diphenoyl peroxide and of a relatively stable 1,2‐dioxetanone derivative, spiro‐adamantyl‐1,2‐dioxetanone. The results indicate a very low medium viscosity effect on the quantum yields of these systems, a priori not compatible with these bimolecular transformations, showing also that their low efficiency cannot be due to solvent‐cavity escape of intermediate radical ion pairs. Additionally, the solvent‐cage effect on the CIEEL efficiency, after the occurrence of the initial electron transfer, proved also to be very low, indicating the intrinsic low viscosity effect on the chemiexcitation step. Therefore, it is concluded that the low efficiency of these systems is intrinsic to the chemiexcitation step and cannot be improved by medium viscosity effects, being possibly due to sterical hindrance on charge‐transfer complex formation in the initial step of the CIEEL. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:32.391548-05:
      DOI: 10.1111/php.12599
       
  • Efficient Degradation of Aqueous Rhodamine B Irradiation Under Indoor
           Light Using a SiO2‐HB Complex
    • Authors: Jucheng Zhang; Heping Yan, Yashun Chen, Rui Chen, Ying He, Wei Liu
      Abstract: An efficient method for the degradation of the dye Rhodamine B (RhB) is reported. A SiO2‐ hypocrellin B (SiO2‐HB) complex was found to work as a catalyst to degrade RhB in aqueous solution at room temperature and atmospheric pressure, over the pH range 1 to 10, under indoor light conditions. This method is capable of removing 82.68% of RhB within 20 min at pH 9. The SiO2‐HB complex was characterized by both scanning electron microscopy and surface area analysis. The reaction progress was examined using ultrahigh pressure liquid chromatography/mass spectrometry and UV‐visible spectroscopy. This process represents an efficient means of decontaminating dye‐containing wastewaters in either highly acidic or weakly alkaline environments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-02T06:20:46.054702-05:
      DOI: 10.1111/php.12596
       
  • Angelica archangelia Prevented Collagen Degradation by Blocking Production
           of Matrix Metalloproteinases in UVB‐exposed Dermal Fibroblasts
    • Abstract: Angelica archangelia (AA), a traditional herb, has attracted attention as an agent with potential for use in the prevention of chronic skin diseases. This study examined the photoprotective effects of AA on the inhibition of matrix metalloproteinases (MMPs) and collagen degradation in UVB‐irradiated normal human dermal fibroblasts (NHDFs). Our results showed that AA markedly blocked collagen degradation by restraining the production of MMPs in UVB‐exposed fibroblasts. We also investigated the underlying mechanism behind the effects of AA. AA attenuated UVB‐triggered interleukin‐6 (IL‐6) and promoted the expression of transforming growth factor β1 (TGF‐β1). Application of AA extract (10, 100 μg/mL) significantly diminished UVB‐induced extracellular signal‐regulated kinase (ERK) and Jun N‐terminal kinase (JNK) phosphorylation, which consequently reduced phosphorylated c‐Fos and c‐Jun. Our results indicated that AA inhibited the UVB‐induced expression of MMPs by inhibiting mitogen‐activated protein kinase (MAPK) signaling pathways and activator protein‐1 (AP‐1) activation. Our results suggest that AA is a promising botanical agent for use against skin photoaging. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T10:57:06.906989-05:
      DOI: 10.1111/php.12595
       
  • Melatonin Mediates Monochromatic Light‐induced Insulin‐like
           Growth Factor 1 Secretion of Chick Liver: Involvement of Membrane
           Receptors
    • Authors: Suqi Li; Jing Cao, Zixu Wang, Yulan Dong, Wenli Wang, Yaoxing Chen
      Abstract: Monochromatic lights influenced the proliferation and differentiation of skeletal satellite cells in broilers by the enhancement of insulin‐like growth factor 1 (IGF‐1) secretion. However, whether melatonin (MEL) mediated monochromatic lights influenced the IGF‐1 secretion is not clear. Newly hatched broilers, including intact, sham operation, and pinealectomy groups, were exposed to blue (BL), green (GL), red (RL) and white light (WL) from a light‐emitting diode system for 14 days. The results showed that GL effectively promoted the secretion of MEL and IGF‐1, the expression of proliferating cell nuclear antigen and MEL receptor subtypes Mel1a, Mel1b and Mel1c in the liver compared to BL and RL in vivo. Moreover, those was a positive correlation between MEL and IGF‐1 (r = 0.834). After pinealectomy, however, these parameters declined, and there were no differences between GL and other monochromatic light treatments. In vitro, exogenous MEL increased hepatocyte proliferation and IGF‐1 secretion. Meanwhile, the MEL enhancements were suppressed by prazosin (selective Mel1c antagonist), followed by luzindole (nonselective Mel1a/Mel1b antagonist), but not suppressed by 4‐phenyl‐2‐propionamideotetralin (selective Mel1b antagonist). These findings demonstrated that MEL mediated the monochromatic light‐induced secretion of IGF‐1 in chicks’ livers by Mel1c and that Mel1a may be involved in this process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T10:15:51.122478-05:
      DOI: 10.1111/php.12594
       
  • Proteomic and Physiological Studies Provide Insight into Photosynthetic
           Response of Rice (Oryza sativa L.) Seedlings to Microgravity
    • Authors: Boya Chen; Yingping Wang
      Abstract: The mechanisms whereby how photosynthesis is regulated and maintained under conditions of microgravity remain incompletely understood. Herein, we took a combination of proteomic and physiological approaches to examine the response of rice (Oryza sativa L.) seedlings to spaceflight conditions. Our results show that both PSI fluorescence emission peak and P700 absorbance amplitude are severely decreased in spaceflight seedlings under microgravity. This is consistent with an observed significant reduction of PSI efficiency (ΦI). To further analyze global changes of protein profiles under microgravity, isobaric tags for relative and absolute quantization (iTRAQ) labeling technology were deployed. 454 differentially expressed proteins were identified by comparison of spaceflight and ground control. Of proteins relevant to photosynthesis thirty‐four were down‐regulated and four were up‐regulated. The significantly down‐regulated ones are essential components of PSI, NDH and the Cytb6f complex. This down‐regulation of PSI proteins and/or protein structure changes may cause the overall reduction of PSI activity. Intriguingly, although abundance of some PSII proteins was altered under microgravity, no significant changes in PSII activity were detected. Taken together, our results suggest that PSI, rather than PSII being usually much more sensitive to environmental stresses, is more susceptible to spaceflight conditions in rice seedlings. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T08:47:13.44606-05:0
      DOI: 10.1111/php.12593
       
  • Promotion of Pro‐Apoptotic Signals by Lysosomal Photodamage:
           Mechanistic Aspects and Influence of Autophagy
    • Authors: David Kessel; Conor L. Evans
      Abstract: Prior studies demonstrated that a low level (LD10‐15) of lysosomal photodamage can sensitize cells to the apoptotic death that results from subsequent mitochondrial photodamage. We have proposed that this process occurs via a calpain‐catalyzed cleavage of the autophagy‐associated protein ATG5 to form a pro‐apoptotic fragment. In this report, we provide evidence for the postulated ATG5 cleavage and show that the sequential photodynamic therapy (PDT) protocol can also partly overcome the adverse effect of hypoxia on the initiation of apoptosis. While autophagy can offer cytoprotection after mitochondrial photodamage, this does not appear to apply when lysosomes are the target. This may account for the ability of very low PDT doses directed at lysosomes to evoke ATG5 cleavage. The resulting pro‐apoptotic effect overcomes intrinsic cytoprotection from mitochondrial photodamage along with a further stimulation of phototoxicity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T08:46:54.648224-05:
      DOI: 10.1111/php.12592
       
  • Co‐axial Electrospinning Method for the Preparation
           of TiO2@CdS/PVA Composite Nano‐fiber Mat and
           Investigation on its Photodegradation Catalysis
    • Authors: Yanmei Luo; Yiru Jia, Dexian Zhang, Xinjian Cheng
      Abstract: TiO2/PVA composite nano‐fiber mat was prepared via an electro‐spinning technology. SH‐TiO2‐SiO2 hybrid particles and PVA solution were injected through a co‐axial syringe, yielding a composite nano‐fiber mat. The as‐prepared SH‐TiO2‐SiO2/PVA composite nano‐fiber mat was immersed in Cd2+ cation solution and S2‐ anion solution in turn. Thus, yellow TiO2@CdS/PVA composite nano‐fiber mats were prepared. By adjusting the number of times a mat was immersed in the Cd2+ and S2‐ solutions, different amounts of CdS particles attaching to the mats were obtained. Both SH‐TiO2‐SiO2/PVA and TiO2@CdS/PVA composite nano‐fiber mats were employed to catalyze the photo‐degradation of a model dye, methylene blue. The photo‐degradation performance could be greatly enhanced by the introduction of CdS particles anchoring onto TiO2 particles. The photo‐degradation efficiency reached 99.2% within 180 min. Also, the nano‐fiber mat could be recycled and reused at least 10 times. The photo‐degradation efficiency of TiO2@CdS/PVA composite nano‐fiber mats remained 68.8% for 10 cycles. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T09:10:41.715286-05:
      DOI: 10.1111/php.12591
       
  • Photoenolization of o‐Methylvalerophenone Ester Derivative
    • Authors: Anushree Das; Emily A. Lao, Anna D. Gudmundsdottir
      Abstract: Photolysis of ester 1 in argon‐saturated methanol and acetonitrile does not produce any product, whereas irradiation of 1 in oxygen‐saturated methanol yields peroxide 2. Laser flash photolysis studies demonstrate that 1 undergoes intramolecular H atom abstraction to form biradical 3 (λmax ~340 nm), which intersystem crosses to form photoenols Z‐4 and E‐4 (λmax ~380 nm). Photoenols 4 decay by regenerating ester 1. With the aid of density functional theory calculations, it was concluded the photoenol E‐4 does not undergo spontaneous lactonization or electrocyclic ring closure because the transition state barriers for these reactions are too large to compete with reketonization of E‐4 to form 1. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-09T01:55:40.068332-05:
      DOI: 10.1111/php.12590
       
  • Photocatalytic Treatment of Desalination Concentrate Using Optical Fibers
           Coated With Nanostructured Thin Films: Impact of Water Chemistry and
           Seasonal Climate Variations
    • Authors: Lu Lin; Huiyao Wang, Hongmei Luo, Pei Xu
      Abstract: Treatment of desalination concentrate can reduce concentrate volume for disposal, increase water recovery, and convert waste to resource. However, concentrate treatment is costly and energy intensive due to high concentrations of salt and recalcitrant organic matter in concentrate. Photocatalytic oxidation provides a novel energy neutral technology for concentrate treatment by degrading organic contaminants. Polymer assisted hydrothermal deposition method was used to synthesize innovative pure and Fe‐doped TiO2 mixed‐phase nanocomposite thin films on side‐glowing optical fibers (SOFs). The properties of the photocatalysts coated SOF were characterized by surface morphology, nanostructure, crystallite size and phase, and zeta potential. Photodegradation efficiency and durability of the photocatalysts treating different types of desalination concentrate was studied under natural sunlight. Synthetic solutions and reverse osmosis (RO) concentrates from brackish water and municipal wastewater desalination facilities were tested to elucidate the impact of water chemistry, operating conditions, and seasonal climate variations (solar irradiation intensity and temperature) on photocatalytic efficiency. High ionic strength and divalent electrolyte ions in RO concentrate accelerated photocatalytic process while the presence of carbonate species and organic matter hindered photodegradation. Outdoor testing of immobilized continuous‐flow photoreactors suggested that the catalyst‐coated SOFs can utilize a wide spectrum of natural sunlight and achieved durable photocatalytic performance. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-02T08:35:43.852265-05:
      DOI: 10.1111/php.12589
       
  • The CO Photodissociation and Recombination Dynamics of the W172Y/F282T
           
    • Abstract: In the ligand channel of the cytochrome c oxidase from Rhodobacter sphaeroides (Rs aa3) W172 and F282 have been proposed to generate a constriction that may slow ligand access to and from the active site. To explore this issue, the tryptophan and phenylalanine residues in Rs aa3 were mutated to the less bulky tyrosine and threonine residues, respectively, which occupy these sites in Thermus thermophilus (Tt) ba3 cytochrome oxidase. The CO photolysis and recombination dynamics of the reduced wild‐type Rs aa3 and the W172Y/F282T mutant were investigated using time‐resolved optical absorption spectroscopy. The spectral changes associated with the multiple processes are attributed to different conformers. The major CO recombination process (44 μs) in the W172Y/F282T mutant is ~500 times faster than the predominant CO recombination process in the wild‐type enzyme (~23 ms). Classical dynamic simulations of the wild‐type enzyme and double mutant showed significant structural changes at the active site in the mutant, including movement of the heme a3 ring D propionate toward CuB and reduced binuclear cavity volume. These structural changes effectively close the ligand exit pathway from the binuclear center, providing a basis for the faster CO recombination in the double mutant. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-31T05:56:09.53871-05:0
      DOI: 10.1111/php.12587
       
  • Caffeic Acid Inhibits Chronic UVB Induced Cellular Proliferation Through
           JAK‐STAT3 Signaling in Mouse Skin
    • Authors: Agilan Balupillai; N. Rajendra Prasad, Kanimozhi Govindasamy, Karthikeyan Ramasamy, Ganesan Muthusamy, Mohana Shanmugam, Velmurugan Devadasan, Ananthakrishnan Dhanapalan
      Abstract: Signal transducers and activators of transcription 3 (STAT3) play a critical role in inflammation, proliferation and carcinogenesis. Inhibition of JAK‐STAT3 signaling is proved to be a novel target for prevention of UVB induced skin carcinogenesis. In this study, chronic UVB irradiation (180 mJ/cm2; weekly thrice for 30 weeks) induces the expression of IL‐10 and JAK1 eventually activates the STAT3 which leads to the transcription of proliferative and anti‐apoptotic markers such as PCNA, Cyclin‐D1, Bcl2 and Bcl‐xl, respectively. Caffeic acid (CA) inhibits JAK‐STAT3 signaling, thereby induces apoptotic cell death by upregulating Bax, Cytochrome‐C, Caspase‐9 and Caspase‐3 expression in mouse skin. Furthermore, TSP‐1 is an anti‐angiogeneic protein, which is involved in the inhibition of angiogenesis and proliferation. Chronic UVB exposure decreased the expression of TSP‐1 and pretreatment with CA prevented the UVB induced loss of TSP‐1 in UVB irradiated mouse skin. Thus, CA offers protection against UVB‐induced photocarcinogenesis probably through modulating the JAK‐STAT3 in the mouse skin. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-31T05:55:45.281621-05:
      DOI: 10.1111/php.12588
       
  • An Understanding of the Photocatalytic Properties and Pollutant
           Degradation Mechanism of SrTiO3 Nanoparticles
    • Abstract: Strontium titanate nanoparticles have attracted much attention due to their physical and chemical properties, especially as photocatalysts under ultraviolet irradiation. In this paper, we analyze the effect of heating rate during the crystallization process of SrTiO3 nanoparticles in the degradation of organic pollutants. The relationship between structural, morphological and photocatalytic properties of the SrTiO3 nanoparticles was investigated by using different techniques. Transmission electron microscopy and N2 adsorption results show that particle size and surface properties are tuned by the heating rate of the SrTiO3 crystallization process. The SrTiO3 nanoparticles showed good photoactivity for the degradation of methylene blue, rhodamine B and methyl orange dyes, driven by a non‐selective process. The SrTiO3 sample with the largest particle size exhibited higher photoactivity per unit area, independent of the molecule to be degraded. The results pointed out that the photodegradation of MB dye catalyzed by SrTiO3 is caused by the action of VB holes (direct pathway), and the indirect mechanism has a negligible effect, i.e., degradation by O2‐• and •OH radicals attack. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-24T01:40:44.193922-05:
      DOI: 10.1111/php.12586
       
  • Functional and Photochemical Characterization of a Light‐Driven
           Proton Pump from the Gammaproteobacterium Pantoea vagans
    • Authors: Yuki Sudo; Susumu Yoshizawa
      Abstract: Photoactive retinal proteins are widely distributed throughout the domains of the microbial world (i.e., bacteria, archaea, and eukarya). Here we describe three retinal proteins belonging to a phylogenetic clade with a unique DTG motif. Light‐induced decrease in the environmental pH and its inhibition by carbonyl cyanide m‐chlorophenylhydrazone revealed that these retinal proteins function as light‐driven outward electrogenic proton pumps. We further characterized one of these proteins, Pantoea vagans rhodopsin (PvR), spectroscopically. Visible spectroscopy and high‐performance liquid chromatography revealed that PvR has an absorption maximum at 538 nm with the retinal chromophore predominantly in the all‐trans form (>90%) under both dark and light conditions. We estimated the pKa values of the protonated Schiff base of the retinal chromophore and its counterion as approximately 13.5 and 2.1, respectively, by using pH titration experiments, and the photochemical reaction cycle of PvR was measured by time‐resolved flash‐photolysis in the millisecond timeframe. We observed a blue‐shifted and a red‐shifted intermediate, which we assigned as M‐like and O‐like intermediates, respectively. Decay of the M‐like intermediate was highly sensitive to environmental pH, suggesting that proton uptake is coupled to decay of the M‐like intermediate. From these results, we propose a putative model for the photoreaction of PvR. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-11T09:38:28.232537-05:
      DOI: 10.1111/php.12585
       
  • High Temperature Affects Photosynthetic and Molecular Processes in
           Field‐Cultivated Vitis vinifera L. × Vitis labrusca L
    • Authors: Qian Zha; Xiaojun Xi, Aili Jiang, Yihua Tian
      Abstract: High temperature stress markedly influences grape growth and development. However, how high temperature stress response differs between controlled and field cultivation of grape is poorly understood. In this study, the effects of heat treatment on grapevines were studied for changes in photosystem II (PSII) activity and expression levels of heat‐responsive genes and heat shock protein HSP21. July 31st, 2015 was considered as the post high‐temperature treatment (“42°C”; temperatures above 40°C for a period of time each day ranging from 1‐7 hours) under field cultivation in our experiment. The recovery of chlorophyll fluorescence indicators and the increasing expression of heat‐responsive genes and the heat shock protein HSP21 suggested the development of heat tolerance in the form of acclimation in grape. Changes in various parameters of photosynthetic pigment fluorescence and of the electron transport chain (Fv/Fm, PIABS, Wk, RCQA, ΦPo, and ΦEo) between “42°C” and the 45°C treatment demonstrated that the donor side, reaction center, and acceptor side of PSII were influenced by a critical high temperature. Furthermore, the difference between the two cultivation conditions studied was attributed to other environment factors and inherent tree vigor. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:29:56.249647-05:
      DOI: 10.1111/php.12584
       
  • Accelerated Regeneration of ATP‐level After Irradiation in Human
           skin Fibroblasts by Coenzyme Q10
    • Abstract: Human skin is exposed to a number of harmful agents of which the ultraviolet (UV) component of solar radiation is the most important. UV‐induced damages include direct DNA lesions as well as oxidative damage in DNA, proteins and lipids caused by reactive oxygen species (ROS). Being the main site of ROS generation in the cell, mitochondria are particularly affected by photostress. The resulting mitochondrial dysfunction may have negative effects on many essential cellular processes. To counteract these effects, coenzyme Q10 (CoQ10) is used as a potent therapeutic in a number of diseases. We analyzed the mitochondrial respiration profile, the mitochondrial membrane potential and cellular ATP‐level in skin fibroblasts after irradiation. We observed an accelerated regeneration of cellular ATP‐level, a decrease in mitochondrial dysfunction as well as a preservation of the mitochondrial membrane potential after irradiation in human skin fibroblasts by treatment with CoQ10. We conclude that the faster regeneration of the ATP‐level was achieved by a preservation of mitochondrial function by the addition of CoQ10 and that the protective effect of CoQ10 is primarily mediated via its antioxidative function. We suggest also that it might be further dependent on a stimulation of DNA repair enzymes by CoQ10. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-06T06:23:38.637168-05:
      DOI: 10.1111/php.12583
       
  • New Insight into the Water‐Soluble Chlorophyll‐Binding Protein
           from Lepidium virginicum
    • Authors: Adam Kell; Dominika Bednarczyk, Khem Acharya, Jinhai Chen, Dror Noy, Ryszard Jankowiak
      Abstract: The present study describes new recombinant water‐soluble chlorophyll (Chl) binding proteins (WSCP) from Lepidium virginicum (LvWSCP). This complex binds four Chls (i.e., two dimers of Chls) per protein tetramer. We show that absorption, emission, hole‐burned (HB) spectra and the shape of the zero‐phonon hole (ZPH) action spectrum are consistent with the presence of uncorrelated excitation energy transfer between two Chl dimers. Thus, there is no need to include slow protein relaxation within the lowest excited state (as suggested in a previous analysis of cauliflower WSCP [Schmitt, F.‐J. et al. (2008) J. Phys. Chem. B, 112, 13951; Pieper, J. et al. (2011) J. Phys. Chem. B, 115, 4053]) in order to explain the large shift observed between the maxima of the ZPH action and emission spectra. Experimental evidence is provided which shows that electron exchange between lowest energy Chls and the protein may occur, i.e., electrons can be trapped at low temperature by nearby aromatic amino acids. The latter explains the shape of nonresonant HB spectra (i.e., the absence of antihole), demonstrating that the hole‐burning process in LvWSCP is largely photochemical in nature, though a small contribution from non‐photochemical hole burning (in resonant holes) is also observed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-23T13:36:02.344055-05:
      DOI: 10.1111/php.12581
       
  • Self‐Reported Changes in Sun‐Protection Behaviours at
           Different Latitudes in Australia
    • Authors: Ngadiman Djaja; Monika Janda, Robyn M. Lucas, Simone L. Harrison, Ingrid van der Mei, Peter R. Ebeling, Rachel E. Neale, David C. Whiteman, Madeleine Nowak, Michael G. Kimlin
      Abstract: Sun exposure is the most important source of vitamin D, but is also a risk factor for skin cancer. This study investigated attitudes toward vitamin D, and changes in sun exposure behaviour due to concern about adequate vitamin D. Participants (n=1,002) were recruited from four regions of Australia and completed self‐ and interviewer‐administered surveys. Chi‐square tests were used to assess associations between participants’ latitude of residence, vitamin D‐related attitudes and changes in sun exposure behaviours during the last summer. Multivariate logistic regression analyses were used to model the association between attitudes and behaviours. Overall, people who worried about their vitamin D status were more likely to have altered sun protection and spent more time in the sun people not concerned about vitamin D. Concern about vitamin D was also more common with increasing latitude. Use of novel Item Response Theory analysis highlighted the potential impact of self‐reported behaviour change on skin cancer predisposition due concern to vitamin. This cross sectional study shows that the strongest determinants of self‐reported sun‐protection behaviour changes due to concerns about vitamin D were attitudes and location, with people at higher latitudes worrying more. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-23T13:34:35.888972-05:
      DOI: 10.1111/php.12582
       
  • Stress Tolerance of the Endemic Antarctic Brown Alga Desmarestia anceps to
           UV Radiation and Temperature is Mediated by High Concentrations of
           Phlorotannins
    • Abstract: The endemic Antarctic brown macroalga Desmarestia anceps is strongly shade adapted, but shows also a high capacity to cope with different environmental stressors, e.g. UV radiation and temperature. Therefore this species colonizes wide depth gradients, which are characterized by changing environmental conditions. In the present study, we examine whether the different physiological abilities allowing D. anceps to grow across a wide depth range is determined by high levels of phlorotannins. Photosynthesis, measured by PAM‐fluorometry, the contents of soluble phlorotannins, antioxidant capacities of field‐grown were analysed in response to different conditions of radiation (PAR and PAR+UV) and temperature (2, 7 and 12°C). The results show that maximal quantum of fluorescence (Fv/Fm) decreased with increasing doses of UV radiation but remained unaffected by temperature. High levels of soluble phlorotannins were detected and confirmed by microscopic observation revealing the abundance of large physodes. Exposure to UV radiation and elevated temperature showed that phlorotannins were not inducible by UV but increased at 12°C. ROS scavenging capacity was positively correlated with the contents of phlorotannins. In general, highest contents of phlorotannins were correlated with the lowest inhibition of Fv/Fm in all experimental treatments, highlighting the UV‐protective role of these compounds in D. anceps. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-20T03:16:49.668408-05:
      DOI: 10.1111/php.12580
       
  • The Lack of Lutein Accelerates the Extent of Light‐induced Bleaching
           
    • Authors: Konstantin Dobrev; Daniela Stanoeva, Maya Velitchkova, Antoaneta V. Popova
      Abstract: The high light‐induced bleaching of photosynthetic pigments and the degradation of proteins of light‐harvesting complexes of PSI and PSII were investigated in isolated thylakoid membranes of Arabidopsis thaliana, wt and lutein deficient mutant lut2, with the aim of unraveling the role of lutein for the degree of bleaching and degradation. By the means of absorption spectroscopy and Western blot analysis we show that the lack of lutein leads to a higher extent of pigment photobleaching and protein degradation in mutant thylakoid membranes in comparison with wt. The highest extent of bleaching is suffered by chlorophyll a and carotenoids, while chlorophyll b is bleached in lut2 thylakoids during long periods at high illumination. The high‐light induced degradation of Lhca1, Lhcb2 proteins and PsbS was followed and it is shown that Lhca1is more damaged than Lhcb2. The degradation of analyzed proteins is more pronounced in lut 2 mutant thylakoid membranes. The lack of lutein influences the high light‐induced alterations in organization of pigment‐protein complexes as revealed by 77K fluorescence. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-16T22:59:50.117697-05:
      DOI: 10.1111/php.12576
       
  • Electric Field‐Assisted Photochemical Water Splitting Should Operate
           with 287 nm Light
    • Abstract: The major photoreaction of water is the homolytic splitting of one O‐H bond starting from the 11B1 excited state (λmax = 167 nm). This reaction produces H• and •OH radicals. The combination of two H• atoms leads to the potential energy carrier dihydrogen. However, the energy required to obtain the photoreactive 11B1 electronic state is about 7.4 eV which cannot be effectively provided by solar radiation. The sun light spectrum on earth comprises the visible and ultraviolet region but shows vanishing intensity near 7 eV (177.1 nm). This work provides theoretical evidence that the photoreactive 11B1 state of water can be shifted into the ultraviolet (UV‐B) light region (≈ 287 nm) by including explicitly an electric field in the calculations of the water absorption spectrum. To accomplish such bathochromic shift, a large field strength of 3.08 VÅ−1 is required. The field‐dependent excitation energies were calculated by applying the symmetry adapted cluster configuration interaction (SAC‐CI) procedure. Based on this theoretical analysis, we propose that photochemical water splitting can be accomplished by means of 287 nm light provided the water molecule is favorably oriented by an external electric field and is subsequently activated by a reversal of the field orientation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-15T08:06:44.463119-05:
      DOI: 10.1111/php.12578
       
  • UVB Generates Microvesicle Particle Release in Part Due to
           Platelet‐activating Factor Signaling
    • Authors: Ji C. Bihl; Christine M. Rapp, Yanfang Chen, Jeffrey B. Travers
      Abstract: The lipid mediator platelet‐activating factor (PAF) and oxidized glycerophosphocholine PAF agonists produced by ultraviolet B (UVB) have been demonstrated to play a pivotal role in UVB‐mediated processes, from acute inflammation to delayed systemic immunosuppression. Recent studies have provided evidence that microvesicle particles (MVPs) are released from cells in response to various signals including stressors. Importantly, these small membrane fragments can interact with various cell types by delivering bioactive molecules. The present studies were designed to test if UVB radiation can generate MVP release from epithelial cells, and the potential role of PAF receptor (PAF‐R) signaling in this process. We demonstrate that UVB irradiation of the human keratinocyte‐derived cell line HaCaT resulted in the release of MVPs. Similarly, treatment of HaCaT cells with the PAF‐R agonist carbamoyl PAF also generated equivalent amounts of MVP release. Of note, pretreatment of HaCaT cells with antioxidants blocked MVP release from UVB but not PAF‐R agonist N‐methyl carbamyl PAF (CPAF). Importantly, UVB irradiation of the PAF‐R‐negative human epithelial cell line KB and KB transduced with functional PAF‐Rs resulted in MVP release only in PAF‐R‐positive cells. These studies demonstrate that UVB can generate MVPs in vitro and that PAF‐R signaling appears important in this process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-15T08:04:56.9521-05:00
      DOI: 10.1111/php.12577
       
  • Effects of Narrow‐band IR‐A and of Water‐filtered
           Infrared A (wIRA) on Fibroblasts
    • Authors: Lilla Knels; Monika Valtink, Helmut Piazena, Jamlec De la Vega Marin, Kerstin Gommel, Amelie Lupp, Cora Roehlecke, Mirko Mehner, Richard H.W. Funk
      Abstract: Exposures of the skin with electromagnetic radiation of wavelengths between 670 nm and 1400 nm are often used as a general treatment to improve wound healing and reduce pain, e.g. in chronic diabetic skin lesions. We investigated the effects of water‐filtered infrared‐A (wIRA) and of narrow‐band IR‐A provided by an LED (LED‐IR‐A) irradiation in vitro on 3T3 fibroblast cultures under defined conditions with and without glyoxal administration. Glyoxal triggers the formation of advanced glycation end products, thereby mimicking a diabetic metabolic state. Cell viability and apoptotic changes were determined by flow cytometry after vital staining with annexin V, YO–PRO–1 and propidium iodide, and by SubG1 assay. Mitochondrial function and oxidative stress were examined by vital staining for radical production, mitochondrial membrane potential (MMP), and the ratio of reduced to oxidized glutathione (GSH/GSSG). The metabolic state was monitored by a resazurin conversion assay. The numbers of apoptotic cells were reduced in cultures irradiated with wIRA or LED‐IR‐A. More mitochondria showed a well polarized MMP after wIRA irradiation in glyoxal damaged cells. LED‐IR‐A treatment specifically restored the GSH/GSSG ratio. The immediate positive effects of wIRA and LED‐IR‐A observed in living cells, particularly on mitochondria, reflect the therapeutic benefits of wIRA and LED‐IR‐A. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-15T03:16:40.928084-05:
      DOI: 10.1111/php.12579
       
  • Hydrothermal Preparation and Characterization of TiO2/BiVO4 Composite
           Catalyst and its Photolysis of Water to Produce Hydrogen
    • Authors: Zicong Jian; Shaobin Huang, Yaya Cao, Yongqing Zhang
      Abstract: In this present work, Bismuth vanadate composited photocatalyst were synthesized and characterized. The X‐ray diffractometry and Raman results showed that the particles were well crystallized, and performed as the complex of monoclinic BiVO4 and TiO2. Electron microscopy expressed the photocatalyst were high crystallization, agglutination and irregular shape, and adhered by a lot of TiO2 particles. The study of surface areas showed that the specific surface area of 30‐BiVO4/TiO2 composited was 112 m2·g−1, which was nearly 10 times of pure BiVO4. The ultraviolet‐visible diffuse reflectance spectra indicated the composited photocatalyst were effectively in visible light. The activity of photocatalytic water splitting was studied. The results showed that monomer BiVO4 photocatalyst was not able to produced hydrogen under any light source. BiVO4/TiO2 composited photocatalyst, however, were capable of generating hydrogen. Under UV light irradiated 120 min, 1 g catalyst dispersed in 50 mL deionized water produced almost 1 mL hydrogen, such productivity of hydrogen was higher than that of P25‐TiO2. And the experiment of photocatalytic decomposition water under visible light also confirmed that BiVO4/TiO2 composited photocatalyst had the ability of water splitting. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-06T01:33:51.465395-05:
      DOI: 10.1111/php.12575
       
  • Issue Information
    • Pages: 361 - 362
      PubDate: 2016-05-03T00:01:24.528219-05:
      DOI: 10.1111/php.12515
       
 
 
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