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Publisher: SciELO   (Total: 717 journals)

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Showing 401 - 600 of 717 Journals sorted alphabetically
Psicologia USP     Open Access   (SJR: 0.123, h-index: 6)
Psychology & Neuroscience     Open Access   (Followers: 15, SJR: 0.172, h-index: 8)
Psychology in Society     Open Access   (Followers: 2)
Psykhe (Santiago)     Open Access   (SJR: 0.194, h-index: 8)
Química Nova     Open Access   (SJR: 0.262, h-index: 50)
Radiologia Brasileira     Open Access   (Followers: 1, SJR: 0.211, h-index: 9)
RAE-eletrônica     Open Access   (Followers: 2)
RAM. Revista de Administração Mackenzie     Open Access  
RCOE     Open Access  
REAd : Revista eletrônica de administração     Open Access  
Región y Sociedad     Open Access  
Relações Internacionais (R:I)     Open Access  
Religião e Sociedade     Open Access   (Followers: 3)
Rem : Revista Escola de Minas     Open Access   (Followers: 1, SJR: 0.303, h-index: 9)
Revista Andaluza de Medicina del Deporte     Open Access   (Followers: 2, SJR: 0.152, h-index: 6)
Revista Archivo Médico de Camagüey     Open Access  
Revista Árvore     Open Access   (Followers: 1, SJR: 0.606, h-index: 20)
Revista Brasileira de Biologia     Open Access  
Revista Brasileira de Cardiologia Invasiva     Open Access   (SJR: 0.139, h-index: 5)
Revista Brasileira de Ciência Avicola     Open Access   (Followers: 1, SJR: 0.292, h-index: 12)
Revista Brasileira de Ciência do Solo     Open Access   (Followers: 1, SJR: 0.716, h-index: 37)
Revista Brasileira de Ciência Política     Open Access  
Revista Brasileira de Ciências do Esporte     Open Access   (Followers: 1, SJR: 0.147, h-index: 2)
Revista Brasileira de Ciências Farmaceuticas     Open Access  
Revista Brasileira de Ciências Sociais     Open Access   (Followers: 1, SJR: 0.138, h-index: 8)
Revista Brasileira de Cineantropometria & Desempenho Humano     Open Access   (SJR: 0.194, h-index: 13)
Revista Brasileira de Cirurgia Cardiovascular     Open Access   (Followers: 1, SJR: 0.303, h-index: 16)
Revista Brasileira de Cirurgia Plástica     Open Access   (Followers: 1)
Revista Brasileira de Coloproctologia     Open Access  
Revista Brasileira de Economia     Open Access   (Followers: 1, SJR: 0.215, h-index: 8)
Revista Brasileira de Educação     Open Access   (SJR: 0.202, h-index: 6)
Revista Brasileira de Educação Especial     Open Access   (SJR: 0.205, h-index: 6)
Revista Brasileira de Educação Física e Esporte     Open Access   (Followers: 1)
Revista Brasileira de Educação Medica     Open Access  
Revista Brasileira de Enfermagem     Open Access   (SJR: 0.268, h-index: 13)
Revista Brasileira de Engenharia Agrícola e Ambiental     Open Access   (Followers: 1, SJR: 0.596, h-index: 21)
Revista Brasileira de Engenharia Biomédica     Open Access   (SJR: 0.16, h-index: 4)
Revista Brasileira de Ensino de Fisica     Open Access   (SJR: 0.204, h-index: 6)
Revista Brasileira de Entomologia     Open Access   (Followers: 1, SJR: 0.402, h-index: 20)
Revista Brasileira de Epidemiologia     Open Access   (Followers: 2, SJR: 0.412, h-index: 19)
Revista Brasileira de Estudos de População     Open Access   (Followers: 1, SJR: 0.214, h-index: 7)
Revista Brasileira de Estudos Pedagógicos     Open Access  
Revista Brasileira de Farmacognosia     Open Access   (SJR: 0.447, h-index: 27)
Revista Brasileira de Fisiologia Vegetal     Open Access  
Revista Brasileira de Fruticultura     Open Access   (SJR: 0.442, h-index: 17)
Revista Brasileira de Geofísica     Open Access   (Followers: 2, SJR: 0.181, h-index: 13)
Revista Brasileira de Geriatria e Gerontologia     Open Access  
Revista Brasileira de Hematologia e Hemoterapia     Open Access   (Followers: 1, SJR: 0.302, h-index: 11)
Revista Brasileira de Historia     Open Access   (Followers: 3, SJR: 0.1, h-index: 5)
Revista Brasileira de Linguística Aplicada     Open Access  
Revista Brasileira de Medicina do Esporte     Open Access   (Followers: 1, SJR: 0.184, h-index: 17)
Revista Brasileira de Meteorologia     Open Access   (Followers: 1, SJR: 0.191, h-index: 3)
Revista Brasileira de Oftalmologia     Open Access   (SJR: 0.135, h-index: 8)
Revista Brasileira de Otorrinolaringologia     Open Access  
Revista Brasileira de Parasitologia Veterinaria     Open Access   (SJR: 0.535, h-index: 17)
Revista Brasileira de Plantas Medicinais     Open Access   (Followers: 1, SJR: 0.265, h-index: 17)
Revista Brasileira de Política Internacional     Open Access   (SJR: 0.188, h-index: 8)
Revista Brasileira de Psiquiatria     Open Access   (Followers: 1, SJR: 0.823, h-index: 36)
Revista Brasileira de Reumatologia     Open Access   (SJR: 0.354, h-index: 17)
Revista Brasileira de Saúde e Produção Animal     Open Access   (SJR: 0.243, h-index: 5)
Revista Brasileira de Saúde Materno Infantil     Open Access   (SJR: 0.198, h-index: 16)
Revista Brasileira de Sementes     Open Access  
Revista Brasileira de Terapia Intensiva     Open Access   (Followers: 1, SJR: 0.3, h-index: 6)
Revista Brasileira de Zoologia     Open Access  
Revista Brasileira de Zootecnia     Open Access   (Followers: 2, SJR: 0.436, h-index: 39)
Revista CEFAC     Open Access  
Revista Centro Azúcar     Open Access  
Revista Ceres     Open Access   (SJR: 0.433, h-index: 6)
Revista Chapingo. Serie horticultura     Open Access   (SJR: 0.127, h-index: 5)
Revista Chilena de Anatomia     Open Access  
Revista Chilena de Cardiología     Open Access  
Revista Chilena de Cirugia     Open Access   (SJR: 0.135, h-index: 6)
Revista Chilena de Derecho     Open Access   (SJR: 0.223, h-index: 4)
Revista Chilena de Derecho Privado     Open Access  
Revista Chilena de Enfermedades Respiratorias     Open Access   (SJR: 0.15, h-index: 7)
Revista Chilena de Infectología     Open Access   (SJR: 0.208, h-index: 14)
Revista Chilena de Literatura     Open Access   (Followers: 2, SJR: 0.102, h-index: 3)
Revista Chilena de Neuro-Psiquiatria     Open Access   (SJR: 0.165, h-index: 9)
Revista Chilena de Nutricion     Open Access   (Followers: 1, SJR: 0.198, h-index: 10)
Revista Chilena de Obstetricia y Ginecologia     Open Access   (Followers: 1, SJR: 0.103, h-index: 8)
Revista Chilena de Pediatria     Open Access   (SJR: 0.139, h-index: 11)
Revista Chilena de Radiologia     Open Access   (Followers: 1, SJR: 0.101, h-index: 4)
Revista Ciência Agronômica     Open Access   (SJR: 0.578, h-index: 14)
Revista Ciencias Técnicas Agropecuarias     Open Access  
Revista Científica Ciencia Médica     Open Access  
Revista Científica General José María Córdova     Open Access  
Revista Clínica de Medicina de Familia     Open Access   (Followers: 4)
Revista Clínica de Periodoncia, Implantología y Rehabilitación Oral     Open Access   (Followers: 1)
Revista Colombiana de Anestesiología     Open Access   (Followers: 2, SJR: 0.151, h-index: 5)
Revista Colombiana de Antropologia     Open Access   (Followers: 2, SJR: 0.113, h-index: 2)
Revista Colombiana de Biotecnología     Open Access   (Followers: 1)
Revista Colombiana de Educación     Open Access  
Revista Colombiana de Entomología     Open Access   (Followers: 1, SJR: 0.21, h-index: 11)
Revista Colombiana de Estadística     Open Access   (SJR: 0.419, h-index: 6)
Revista Colombiana de Matemáticas     Open Access   (Followers: 1, SJR: 0.102, h-index: 1)
Revista Colombiana de Psicología     Open Access   (SJR: 0.121, h-index: 3)
Revista Contabilidade & Finanças     Open Access  
Revista Costarricense de Cardiología     Open Access  
Revista Costarricense de Psicología     Open Access  
Revista Cubana de Anestesiología y Reanimación     Open Access   (Followers: 1)
Revista Cubana de Angiología y Cirugía Vascular     Open Access  
Revista Cubana de Cirugía     Open Access   (SJR: 0.12, h-index: 4)
Revista Cubana de Endocrinología     Open Access  
Revista Cubana de Enfermería     Open Access   (Followers: 2, SJR: 0.117, h-index: 4)
Revista Cubana de Estomatologí­a     Open Access   (SJR: 0.11, h-index: 4)
Revista Cubana de Farmacia     Open Access   (Followers: 1, SJR: 0.119, h-index: 5)
Revista Cubana de Hematología, Inmunología y Hemoterapia     Open Access   (SJR: 0.119, h-index: 5)
Revista Cubana de Higiene y Epidemiología     Open Access   (SJR: 0.101, h-index: 7)
Revista Cubana de Información en Ciencias de la Salud     Open Access   (SJR: 0.188, h-index: 5)
Revista Cubana de Informática Médica     Open Access  
Revista Cubana de Investigaciones Biomédicas     Open Access   (Followers: 1, SJR: 0.101, h-index: 7)
Revista Cubana de Medicina     Open Access   (Followers: 2, SJR: 0.132, h-index: 6)
Revista Cubana de Medicina General Integral     Open Access   (Followers: 1, SJR: 0.156, h-index: 9)
Revista Cubana de Medicina Militar     Open Access   (Followers: 1, SJR: 0.1, h-index: 7)
Revista Cubana de Medicina Tropical     Open Access   (SJR: 0.141, h-index: 14)
Revista Cubana de Obstetricia y Ginecología     Open Access   (SJR: 0.101, h-index: 8)
Revista Cubana de Oftalmología     Open Access   (Followers: 1)
Revista Cubana de Ortopedia y Traumatología     Open Access   (SJR: 0.1, h-index: 4)
Revista Cubana de Pediatrí­a     Open Access   (SJR: 0.192, h-index: 7)
Revista Cubana de Plantas Medicinales     Open Access   (Followers: 1, SJR: 0.168, h-index: 8)
Revista Cubana de Salud Pública     Open Access   (SJR: 0.253, h-index: 7)
Revista da Educação Física : UEM     Open Access   (SJR: 0.141, h-index: 3)
Revista da Escola de Enfermagem da USP     Open Access   (Followers: 2, SJR: 0.284, h-index: 19)
Revista da Faculdade de Educação     Open Access  
Revista da Sociedade Brasileira de Fonoaudiologia     Open Access  
Revista da Sociedade Brasileira de Medicina Tropical     Open Access   (SJR: 0.476, h-index: 40)
Revista de Administração Contemporânea     Open Access  
Revista de Administração de Empresas     Open Access   (Followers: 1, SJR: 0.207, h-index: 6)
Revista de Administração Pública     Open Access   (SJR: 0.209, h-index: 9)
Revista de Análisis Económico     Open Access   (SJR: 0.132, h-index: 2)
Revista de Antropologia     Open Access   (Followers: 4)
Revista de Bioética y Derecho     Open Access  
Revista de Biología Marina y Oceanografía     Open Access   (SJR: 0.334, h-index: 16)
Revista de Biología Tropical     Open Access   (Followers: 2, SJR: 0.378, h-index: 27)
Revista de Ciencia Politica     Open Access   (Followers: 2, SJR: 0.168, h-index: 9)
Revista de Ciencia y Tecnología     Open Access  
Revista de Ciências Agrárias     Open Access  
Revista de Ciencias Médicas de Pinar del Río     Open Access  
Revista de Ciencias Sociales     Open Access  
Revista de Derecho     Open Access   (Followers: 1, SJR: 0.164, h-index: 4)
Revista de Derecho (Coquimbo)     Open Access  
Revista de Economia Contemporânea     Open Access   (SJR: 0.117, h-index: 4)
Revista de Economía del Caribe     Open Access  
Revista de Economia e Sociologia Rural     Open Access   (Followers: 2, SJR: 0.248, h-index: 7)
Revista de Economía Institucional     Open Access   (SJR: 0.113, h-index: 3)
Revista de Economia Poli­tíca     Open Access   (Followers: 1, SJR: 0.274, h-index: 10)
Revista de Estudios Historico-Juridicos     Open Access   (Followers: 1, SJR: 0.1, h-index: 3)
Revista de Estudios Sociales     Open Access   (Followers: 1, SJR: 0.143, h-index: 4)
Revista de Filosofia     Open Access   (SJR: 0.11, h-index: 3)
Revista de Geografía Norte Grande     Open Access   (SJR: 0.15, h-index: 7)
Revista de Gestão Costeira Integrada     Open Access  
Revista de Historia Americana y Argentina     Open Access  
Revista de Ingeniería     Open Access  
Revista de la Asociación Española de Neuropsiquiatría     Open Access  
Revista de la Ciencia del Suelo y Nutricion Vegetal     Open Access  
Revista de la Construcción     Open Access   (SJR: 0.259, h-index: 4)
Revista de la Facultad de Derecho y Ciencias Políticas     Open Access  
Revista de la Sociedad Boliviana de Pediatría     Open Access  
Revista de la Sociedad Española de Enfermería Nefrológica     Open Access   (SJR: 0.19, h-index: 4)
Revista de la Universidad Industrial de Santander. Salud     Open Access  
Revista de Medicina Veterinaria     Open Access  
Revista de Microbiologia     Open Access   (Followers: 1)
Revista de Nutrição     Open Access   (SJR: 0.246, h-index: 27)
Revista de Odontologia da UNESP     Open Access  
Revista de Odontologia da Universidade de São Paulo     Open Access  
Revista de Osteoporosis y Metabolismo Mineral     Open Access   (Followers: 1)
Revista de Otorrinolaringología y Cirugía de Cabeza y Cuello     Open Access  
Revista de Protección Vegetal     Open Access  
Revista de Psicología del Trabajo y de las Organizaciones     Open Access   (SJR: 0.211, h-index: 4)
Revista de Psiquiatria Clínica     Open Access   (Followers: 1, SJR: 0.192, h-index: 17)
Revista de Psiquiatria do Rio Grande do Sul     Open Access   (Followers: 1)
Revista de Salud Animal     Open Access  
Revista de Salud Pública     Open Access   (Followers: 1, SJR: 0.138, h-index: 16)
Revista de Saúde Pública     Open Access   (Followers: 1, SJR: 0.629, h-index: 56)
Revista de Sociologia e Polí­tica     Open Access   (Followers: 2, SJR: 0.247, h-index: 6)
Revista Dental Press de Ortodontia e Ortopedia Facial     Open Access   (Followers: 1)
Revista Diacrítica     Open Access  
Revista Direito GV     Open Access   (Followers: 1)
Revista do Colégio Brasileiro de Cirurgiões     Open Access   (SJR: 0.252, h-index: 11)
Revista do Departamento de Psicologia. UFF     Open Access  
Revista do Hospital das Clinicas     Open Access  
Revista do Instituto de Estudos Brasileiros     Open Access  
Revista do Instituto de Medicina Tropical de São Paulo     Open Access   (SJR: 0.485, h-index: 37)
Revista Dor     Open Access  
Revista EIA     Open Access   (Followers: 1)
Revista electrónica de investigación educativa     Open Access   (Followers: 1, SJR: 0.105, h-index: 3)
Revista Española de Cirugía Oral y Maxilofacial     Open Access   (Followers: 1, SJR: 0.121, h-index: 3)
Revista Española de Enfermedades Digestivas     Open Access   (Followers: 1, SJR: 0.344, h-index: 29)
Revista Española de Salud Pública     Open Access   (SJR: 0.269, h-index: 26)
Revista Española de Sanidad Penitenciaria     Open Access   (SJR: 0.15, h-index: 3)
Revista Estudos Feministas     Open Access   (SJR: 0.134, h-index: 9)
Revista Facultad de Ciencias Económicas: Investigación y Reflexión     Open Access  
Revista Facultad de Ingenieria - Universidad de Tarapaca     Open Access   (Followers: 1)
Revista Facultad de Ingeniería Universidad de Antioquia     Open Access   (Followers: 1, SJR: 0.133, h-index: 5)
Revista Facultad Nacional de Agronomía, Medellín     Open Access  
Revista Facultad Nacional de Salud Pública     Open Access  
Revista Gaúcha de Enfermagem     Open Access   (SJR: 0.197, h-index: 8)
Revista Geológica de América Central     Open Access  
Revista Geológica de Chile     Open Access   (Followers: 1)
Revista Gerencia y Políticas de Salud     Open Access   (SJR: 0.144, h-index: 4)

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Journal Cover Journal of the Chilean Chemical Society
  [SJR: 0.2]   [H-I: 21]   [2 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Online) 0717-9324
   Published by SciELO Homepage  [717 journals]
  • STRUCTURAL MODIFICATION OF LIGNAN COMPOUNDS ISOLATED FROM NECTANDRA
           SPECIES (LAURACEAE)

    •  
  • SOLVENT EXTRACTION OF IRON IONS FROM HYDROCHLORIC ACID SOLUTIONS

    • Abstract: In this study Methyl Isobutyl Ketone (MIBK) and acetophenone (Methyl Phenyl Ketone) are presented as suitable agents for removal of Fe(III) from concentrated hydrochloric acid solutions. An extensive study applying 4 parameters was carried out: Time (5, 10,15,20,30 and 60 minutes), Stirring rate (200, 300, 400 and 500 r.p.m), Solvent to HCl Ratio (5%, 10%, 14% and 16%), and initial concentration of Fe ions in crude HCl (95.24, 126 ppm, 330 ppm and 1955 ppm).The best Condition was found to be 30 min - 400 r.p.m - 14 %. The distilled water was used to strip Fe ions out of MIBK; In order to get most of the MIBK dissolved in both the concentrated HCl and water. Diluents were used such as benzene, kerosene and xylene. Xylene gives better recovery of about 96%.
       
  • CONFIRMATION OF DEOXYNIV ALENOL PRESENCE IN CHILEAN WHEAT BY
           HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHY-MASS SPECTROMETRY

    • Abstract: Deoxynivalenol (DON) is a mycotoxin that belongs to trichothecene subgroup B. Due its detrimental effects for human health, DON has been analyzed and detected by nearly all chromatographic methods. The present work reports for the first time the application of HPTLC/MS to confirm the presence of DON in wheat crops. Chromatography was performed on silica gel 60 F254 HPTLC plates using toluene - ethyl acetate - formic acid 6:3:1 (V/V/V) as mobile phase. After post-chromatographic derivatization with 10 % AlCl3, fluorescence detection was carried out at UV 366/>400 nm. Bands identity and purity was confirmed by mass spectrometry acquiring analytes directly from the sample bands by means of TLC/MS elution head-based interface. Both, sample and standard bands showed clear mass signals at m/z 341 that corresponds to the formate adduct of DON [M+HCOO]-. Thus, the presence of DON in the Chilean wheat sample was confirmed.
       
  • A RAPID AND SENSITIVE METHOD FOR DETERMINATION OF CHLORINATED BY-PRODUCTS
           IN TAP WATER SAMPLES

    • Abstract: In this paper, an account for determination of chlorinated byproducts by High Performance Liquid Chromatography in various tap water samples is presented. The key objective of this study was to develop an analytical method for selectively and sensitively detecting the concentration of CBPs in addition to analyze selected parameters affecting CBP formation. Concentration of targeted compounds i.e. hydrazine sulfate, Dichloroacetic acid, Bromodichloromethane and chloroform were analyzed in tap water samples collected from a low socioeconomic area in a developing country. Hydrazine sulfate, Dichloroacetic acid and chloroform were detected in four water samples i.e. T4, T7, T9 and T10 while no samples contained Bromodichloromethane. Presence of these compounds in water is associated with cancer mortality and adverse reproductive outcomes.
       
  • CHEMICAL AND MICROSTRUCTURAL CHANGES IN EUCALYPTUS GLOBULUS FIBERS
           SUBJECTED TO FOUR DIFFERENT PRETREATMENTS AND THEIR INFLUENCE ON THE
           ENZYMATIC HYDROLYSIS

    • Abstract: In order to understand the relation between chemical composition, microscopic structure and enzymatic digestibility, different Eucalyptus globulus wood pretreated samples were examined. Pretreated materials obtained by steam explosion and autohydrolysis were compared with those obtained by organosolv and kraft processes. Chemical analyses of pretreated materials showed a decrease in the content of xylans, except in the kraft pulp. FT-IR spectra showed that the residual lignin in autohydrolysis pulp had experienced greater changes compared to those in steam explosion and organosolv pulps, whereas minor changes in lignin kraft pulp were observed. The fiber morphology indicated that autohydrolysis pretreatment was the most aggressive treatment. Reduction in the content of lignin and its redistribution on the fiber wall were confirmed through confocal laser microscopy. The formation of discrete lignin droplets deposited on the surface of the fibers was observed in all pretreatments, with a higher frequency in organosolv followed by steam explosion. A significant increase in enzymatic accessibility was achieved in organosolv, autohydrolysis and steam explosion pulps, due to xylans removal combined with lignin redistribution. Homogeneous lignin distribution and higher xylan content may be related to the low enzymatic hydrolysis efficiency in kraft pulp.
       
  • SYNTHESIS, CHARACTERIZATION, LUMINESCENCE AND DNA BINDING PROPERTIES OF Ln
           (III)-SCHIFF BASE FAMILY

    • Abstract: Pentadentate Schiff base ligand(N,N-bis(2-hydroxy-1-naphthylidene) diethylenetriamine) (H2L) that exhibits a N3O2 donor set. Five rare earth complexes lanthanide (III), praseodymium (III), neodymium(III), samarium(III)and europium (III) complexes are synthesized and characterized based on elemental analyses, molar conductance, infrared, ultraviolet, thermo gravimetric, X-ray powder diffraction and mass spectral studies. Molar conductivity data suggests that the complexes are 1:1 electrolytics. Infrared spectral data suggest that the ligand binds through two naptholic oxygen atoms, two azomethine nitrogen atoms and one primary amine. IR studies reveal that the complexes contain both coordinating and ionic nitrate ligands. Thermal decomposition studies indicate the presence of two nitrate ions and two water molecules in the inner coordination sphere. Eu3+ and Sm3+ complexes exhibit luminescence properties. Further, the binding properties of these complexes with calf-thymus DNA have been investigated using absorption spectrophotometry.
       
  • THEORETICAL STUDY OF THE PH3-ASSISTED MIGRATION OF A COORDINATED ARYL
           GROUP TO A COORDINATED CO IN THE COMPLEXES RhCpI(CO)(p-XC6H4)

    • Abstract: We report the results of theoretical mechanistic studies on PH3-assisted migration of a coordinated aryl group to a coordinated CO in the complexes RhCpI(CO) (p-XC6H4). The X-substituent effect on thermodynamic and kinetic parameters was explored. The progress of the reaction was quantitatively studied using the bond orders of the Rh-CO bond, and the percentages of bond cleavage (BCij) of Rh-CO bond at the transition state were described. This theoretical study indicates good relationships between barrier energy (ΔE), bond distances variations (Rh-CO and Rh-Ph), activation energy (ΔH‡) , activation free energy (ΔG‡) values with Hammett constants of X-substituents. Linear relationship between ln(k) and the 103Rh magnetic shielding tensors of the product was explored.
       
  • FLOTATION-ASSISTED HOMOGENEOUS LIQUID-LIQUID MICROEXTRACTION FOR TRACE
           DETERMINATION OF URANIUM IN WATER SAMPLES BY ICP-MS

    • Abstract: In this study, a novel method based on floatation assistance of homogeneous liquid-liquid microextraction (FA-HLLME), combined with inductively coupled plasma-mass spectroscopy (ICP-MS) was proposed, for the determination of trace uranium in environmental water samples. As one of the miniaturized separation and extraction techniques, homogenous liquid-liquid microextraction (HLLME) has been widely applied in the field of environmental monitoring and assessment. 1,2-pyridylazo-2-naphthol (PAN) was used as the complexing agent while toluene and methanol were selected as the extraction and homogeneous solvents, respectively. The factors that influenced the extraction efficiency for uranium determination (including pH, extraction and homogeneous solvents, concentration of PAN and NaCl, extraction time) were studied statistically. Under optimum conditions (pH=7.0, 100 μL toluene, 500 μL methanol, 6.4×10-5 mol L-1 PAN, 1.5 mol L-1 NaCl and 60 sec of extraction time), the linear dynamic range for uranium determination was 1.0-500.0 ng L-1 (R²=0.9995), with a corresponding limit of detection (LOD) of was 0.27 ng L-1. The relative standard deviation (R.S.D.) (C=50.0 ng L-1, n=9) was 1.13%, with a corresponding enrichment factor of 360 for uranium extraction. The proposed method was successfully applied for the determination of uranium in different water samples.
       
  • AN ALUMINUM SILOXIDE COMPLEX FOR STEREOSELECTIVE POLYMERIZATION OF
           RACEMIC LACTIDE

    • Abstract: Stereoselective polymerization of lactide is receiving growing attention in polymer science. Herein, a five-coordinate aluminum siloxide complex, [2,2-dimethyl-1,3-propylenebis(3,5-di-tert- butylsalicylideneiminato)] (triphenyl-silanolato) aluminium (III) (1), was prepared from AlEt3, N,N'-(2,2-dimethylpropylene) bis(3,5-di-tert-butylsalicylideneimine) and triphenyl-silanol. X-ray analysis demonstrated that 1 contained a five-coordinate aluminum atom with distorted trigonal bipyramidal geometry in the solid state. ¹H NMR and 13C NMR spectra indicated that the two conformational stereoisomers of 1 tautomerizes rapidly in chloroform or toluene solution at room temperature. 1 showed high stereoselectivity (Pm = 0.84) for the ROP of rac-lactide in toluene at 100°C, and polymerized rac-lactide to crystalline polymer (Tm = 178°C). This is the first report of stereoselective polymerization of rac-lactide using aluminum siloxide as a catalyst.
       
  • DETERMINATION OF BRACHIARIA SPP. FORAGE QUALITY BY NEAR-INFRARED
           SPECTROSCOPY AND PARTIAL LEAST SQUARES REGRESSION

    • Abstract: Characterizing the chemical properties of forage is critical for the production of improved pastures and livestock development. Conventional analysis methods are very time- and material-consuming, whereas near-infrared spectroscopy (NIRS) and chemometric analyses allow a fast simultaneous determination of various chemical or physical properties without the use of solvents or large sample amounts. The present research involved the development of models based on NIRS and partial least squares regression (PLS) to estimate the neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, and crude protein (CP) contents in Brachiaria spp. forage samples. The models were constructed using spectral data in the range of 800 to 1850 nm. Different preprocessing methods were applied, such as standard normal variate and first-/second-derivative transformations. The obtained calibration models were internally cross-validated, displaying validation errors similar to those obtained for conventional methods. The predictive abilities of the developed models were evaluated for external set samples. NDF, ADF, cellulose, and CP contents were estimated with relative errors of prediction (REPs) of 1.8, 2.6, 4.1, and 8.5%, respectively. NIRS predictions are a useful and profitable tool for fast multi-sample chemical property analysis that is required for the assessment of forage quality. The obtained models are suitable for estimating the key chemical characteristics of forage quality. This research contributes a new approach to determining the quality of Brachiaria spp. forage and provides a new technological tool for the improvement of this crop.
       
  • INFLUENCE OF ZnCl2 CONCENTRATION ON THE SELECTIVITY OF A
           Zn(NCS)4 2 --SELECTIVE ELECTRODES AND ITS APPLICATION FOR DETERMINATION
           SCN - IONS IN INDUSTRIAL SOLUTIONS

    • Abstract: The influence of the background concentration of ZnCl2 on the selectivity of Zn(NCS)4(2-)−SE based on QAS to SCN- is studied. The introduction of ZnCl2 into a solution fixes zinc released from the membrane in the form of thiocyanate complex. A high selectivity of the Zn(NCS)4(2-)−SE to SCN- ions is due to the formation of better extractable complexes between zinc and SCN- compared to acidocomplexes of competitive anions. An introduction of 5.0 M ZnCl2 into a solution increases selectivity to SCN- ions by 5 orders of magnitude in the presence of interfering CKO4- ions and more than 4.5 orders of magnitude in the presence of interfering NO3- ions.
       
  • MAGNETIC SOLID PHASE EXTRACTION FOR A NEW HPLC METHOD FOR THE
           DETERMINATION OF GEMIFLOXACIN IN HUMAN PLASMA AND BREAST MILK

    • Abstract: A simple analytical procedure, magnetic solid phase extraction combination to HPLC, has been developed for the analysis of gemifloxacin in human plasma and breast milk. Before chromatographic separation, magnetic solid phase extraction has been applied for sample preparation which is currently preffered extraction technique accordingly its simple, fast and efficient procedure. Fe3O4 magnetic nanoparticles have been used as magnetic adsorbents, the adsorption process has been optimized. RP C18 column has been used with mobile phase composed of acetonitrile-10 mM orthophosphoric acid including 1 mL/L triethylamine (60:40) by isocratic elution with flow rate of 1.3 mL/min. Calibration curve is linear over the range of 0.5-30 μg/mL and 0.5-20 μg/mL for plasma and breast milk, respectively. LOD and LOQ has been found to be 0.15 and 0.5 μg/mL for both matrices. Intraday and interday RSD values are less than 3.57% for both assays. Moreover, the newly developed method provides fast, simple, cost reduced and sensitive assay for gemifloxacin.
       
  • VALIDATED STABILITY INDICATING RP-HPLC METHOD FOR SIMULTANEOUS
           DETERMINATION OF NORTRIPTYLINE AND PREGABALIN IN BULK AND COMBINED DOSAGE
           FORMULATIONS

    • Abstract: A simple and precise stability indicating RP-HPLC method was developed for simultaneous analysis of drug nortriptyline and pregabalin using BDS (250mm x 4.6 mm, 5μ) C18 column at 210 nm of UV detection. Perchloric acid (0.1%) and acetonitrile in the ratio of 55:45 was used as the mobile phase with a flow rate of 1.0 ml/min and linearity response was established over the concentration range of 5-30 μg/ml for nortriptyline and 37.5-225 μg/ml for pregabalin. The active pharmaceutical ingredients recovered for nortriptyline and pregabalin are in the range of 100.60-101.65% and 100.59-101.74% respectively. The method was validated and was found to be stability indicating and can be successfully utilized for the quantitative analysis of pharmaceutical tablet dosage formulations containing nortriptyline and pregabalin.
       
  • SYNTHESIS OF NOVEL 1,2-DIOL CONTAINING AZO DYES FOR POLYMERIC
           SUBSTRATES

    • Abstract: Two novel 1,2-diol containing azo dyes have been synthesized for application on polymeric textile substrates. We used multistep synthesis scheme which involved selectively bonding azo chromophore with glycerol moiety such that only one alcohol out of the three gets bonded to the chromophore while rest two remain unchanged. The 1,2-diol moiety, common in both dyes, is responsible for forming hydrogen bonds with polar sites on a polymeric substrate. The molecular structure of the final molecule and synthesized intermediates were elucidated by UV/Vis, FT-IR, MS (EI, ESI, and CI) and ¹H-NMR spectroscopic techniques. Dyes were applied to polyester and nylon 66 fabrics as disperse dyes by exhaust dyeing method and furnished good to excellent fastness properties on both of them.
       
  • GRINDING IMIDATION OF ANHYDRIDES ON SMECTITE CLAYS AS RECYCLABLE AND
           HETEROGENEOUS CATALYSTS UNDER SOLVENT-FREE CONDITIONS

    • Abstract: Imidation of various anhydrides employing solvent-free grindstone technique using smectite clays as recyclable and green catalysts was examined and obtained excellent yields.
       
  • ADSORPTION OF COOMASSIE BRILLIANT BLUE R-250 DYE ONTO NOVEL ACTIVATED
           CARBON PREPARED FROM NIGELLA SATIVA L. WASTE: EQUILIBRIUM, KINETICS AND
           THERMODYNAMICS RUNNING TITLE: ADSORPTION OF BRILLIANT BLUE DYE ONTO
           NIGELLA SATIVA L. WASTE ACTIVATED CARBON

    • Abstract: In this paper a novel adsorbent was prepared from Nigella sativa L. waste and used for the removal of Coomassie Brilliant Blue dye from wastewater. The preparation of Nigella sativa waste carbon (NSWC) was achieved by adding concentrated sulfuric acid to the precursor material at an impregnation ratio (1: 1) and the mixture was left overnight. The resulting material was washed with sodium bicarbonates and finally oven dried. The kinetics of coomassie brilliant blue adsorption onto NSWC was investigated by three kinetic models. The pseudo-second order model (R² = 0.99) was the best model fitted the experimental data. The equilibrium results revealed that Freundlich model was the best isotherm model fitted (R²= 0.994). Also the value of the Freundlich exponent (n) was found to be 1.174 suggesting the favorable dye adsorption onto NSWC. The thermodynamics results indicated negative values of ΔG proving the spontaneous nature of Brilliant Blue dye adsorption on NSWC. The exothermic nature of the adsorption was also confirmed by the negative value of change in enthalpy ΔH°. Also, the negative value of the activation entropy ΔS° demonstrates the decreased randomness at the solid-solution interface during adsorption. The present study results suggest the possible use of a waste such as Nigella sativa L. waste as a precursor for the development of a new cheap and efficient adsorbent that could be used in dyes removal from wastewater.
       
  • CHARACTERIZATION OF AMORPHOUS ALLOY
           Co87Nb46B15

    • Abstract: This paper presents a discussion of the processing and characterization of alloy Co87Nb46B15 produced by rapid solidification, in which characterization techniques such as X-Ray Diffraction (XRD), scanning electron microscopy and spectroscopy Dispersion Energy (SEM / EDS) and magnetic properties were used, with the study of hysteresis curve. Several researches have been making on nanocrystalline materials, especially cobalt-base alloys, because of their thermodynamic stability, characterization and processing. Amorphous alloys have a structure of ultrafine, homogeneous grains with small crystal clusters in amorphous phase.
       
  • ELECTROANALYTICAL ANALYSIS OF GLASSY CARBON ELECTRODE MODIFIED WITH COOH-
           AND NO2- FUNCTIONALIZED POLYSPYROPHOSPHAZENES

    • Abstract: Glassy carbon electrode modified with COOH- and NO2-functionalized polyspyrophosphazenes were used to study the redox process of a electroactive probe (ferrocene) in non-aqueous electrolyte. The electrochemical behavior of polyphosphazenes substituted with COOH and NO2 groups has been studied using cyclic voltammetry. Their blocking properties depend on the substituent group and on the substitution/nitration degree. The oxoreduction of the couple Fc/Fc+ occurs with rapid redox kinetic at the modified glassy carbon electrode with high nitration degree NO2−functionalized polyspyrophosphazene. The polymers were immobilized on the glassy carbon surface at different concentrations to study surface charge density effect. In this report were studied the reproducibility, repeatability and stability of the modified electrodes.
       
  • ELIMINATION OF INDUSTRIAL TEXTILE DYE BY ELECTROCOAGULATION USING IRON
           ELECTRODES

    • Abstract: Electrocoagulation is a promising technique for the treatment of wastewater like the produced by the textile industry, which generates large volumes of water containing dyes. Thus, synthetic samples of the textile dye acid black 194 (AB194, CI 22910) were treated by this method using iron anodes at two different initial pH values. Tafel studies in the presence and absence of the dye were performed. The complete removal of AB194 from 1.0 L of solution in a static cell was achieved, at short electrolysis times, applying low-density currents at two different initial pH values. In addition, the operating costs by mass consumed anode, per cubic meter electocoagulated and per TOC unit, were assessed to help determine the most efficient conditions, considering a future application of the method in the industry.
       
  • Co2SnO4/CARBON PASTE ELECTRODE AS ELECTROCHEMICAL SENSOR FOR HYDROGEN
           PEROXIDE

    • Abstract: Hydrogen peroxide (H2O2) plays an important role as an intermediary in different biological, chemical and environmental systems. It has been widely used as an oxidizing and antimicrobial agent, in germicides production and textile and paper bleaching. However, it is well known, that H2O2 is a possible responsible in many diseases and is a chemical agent that threatens the environment, so it becomes important to detect peroxide with high accuracy. In this study, carbon paste electrode (CPE), modified with Co2SnO4 was synthesized and tested. It was successfully obtained a non-enzymatic H2O2 detection type sensor, based on Co2SnO4/ CPE composite, showing good linear response in concentration of H2O2 in the range of 88 - 605.9 μM.
       
  • ELECTROCHEMICAL AND PHOTO-ELECTROCHEMICAL PROCESSES OF METHYLENE BLUE
           OXIDATION BY Ti/TiO2 ELECTRODES MODIFIED WITH FE-ALLOPHANE

    • Abstract: This work reports the degradation of methylene blue (MB) on Ti/TiO2 and Ti/TiO2/Fe-allophane electrodes in a pH 3 using 0.1 M Na2SO4 as support electrolyte. SEM micrographs show a homogeneous distribution of TiO2 over the whole electrode surface forming nanotubes and nanopores. Fe-allophane modified electrode shows the formation of large-grains agglomerate on the electrode surface due to allophane, which provides a greater surface area to the electrode due to meso and micropore structures. Preliminary cyclic voltammetry show that Ti/TiO2 has the typical voltammetric response due to Ti(III)/Ti(IV) pair. Diffusional problems were observed through of the film when the electrode is modified with Fe-allophane modifying the quasi-reversible process Ti(III)/Ti(IV). Different kind of methodologies in the degradation process were used: Electrochemistry (EC), Photochemistry (PC), Photoelectrochemistry (PEC) and Adsorption (Ads). These methods were developing to discard any reaction or interaction that is not of interest. On Ti/TiO2 with PC and Ads methodologies was not observed any activity to MB degradation showing that is not photosensitive and that the interaction between this and surface electrode is low. But with EC and PEC degradation to 55% is reached after 3 hours of electrolysis. With Ti/TiO2-Fe-allophane electrodes are observed a higher activity for all methodologies. The PC and Ads methods show that the MB degradation reaches to ~20 % of the initial concentration. As mentioned above, the PC and Ads processes no show degradation on Ti/TiO2, therefore the degradation it only due to the adsorption of MB in/on allophane coat behaving as concentrator matrix. A lower improvement is observed with EC process when is incorporated Ti/TiO2-Fe-allophane is due to the barrier of the electrode surface by oxidation products. With PEC is reached the higher degradation value of ~88 %, showing an improvement of the degradation with the presence of Fe-allophane. The results indicate that the main role of Fe-allophane on the electrode is similar to a concentrator matrix.
       
  • ABSOLUTE CONFIGURATION OF 13-EPIMULINOLIC ACID

    • Abstract: The molecular structure of the title compound [iupac name: 13-epi-8-hydroxy-3-isopropyl-5a,8-dimethyl-2,3,4,5,5a,6,7,8,10a,10b-decahydrocyclohepta[e] indene-3a(1H) acid] is similar to the structure of the known compound mulinolic acid.The structure of this mulinolic acid epimer consists of a mulinane skeleton and the isopropyl, methyl group, carboxylic acid and the hydroxyl group at C3, C8, C5, C13, respectively, which are ß-oriented, whereas the methyl group at C13 are a-oriented. The cyclopentane (A), ciclohexane (B) and cicloheptene (C) rings are trans (A/B) and (B/C) cis fused, and are in an envelope, chair, and twist chair conformation respectively. In the crystal the molecules are linked by two strong intermolecular O-H···O hydrogen bond forming bidimensional supramolecular structures with graph-set notation (12) and (46).The absolute configuration of the title compound which has been determined from the refinement of the Flack parameter16. On this basis the absolute configuration was assigned as C3R, C5S, C8S, C9S,C10S and C13S.
       
  • DETERMINATION OF UREA USING p -N,N-DIMETHYLAMINOBENZALDEHYDE: SOLVENT
           EFFECT AND INTERFERENCE OF CHITOSAN

    • Abstract: An optimized spectroscopic methodology for the quantification of urea using p-dimethylaminobenzaldehyde (DMAB) as a derivatizing reagent is proposed to avoid changes in reproducibility caused by aging of acidic DMAB solutions, and the unintended use of different solvents. Four solvents; ethanol, methanol, 2-propanol and acetonitrile are evaluated. Acetonitrile has never been reported for the determination of urea with DMAB, and it is found to be the best medium for the quantification of urea due to its aprotic nature. The use of acetonitrile allows a more stable reaction system, which results in a faster urea quantification, less acid consumption and a more sensitive spectroscopic method. Taking into account that polymer matrices of chitosan are being used recently to develop controlled release fertilizers of urea, a complementary study is carried out to determine any interference by released chitosan macromolecules with different molecular mass and degree of deacetylation in the optimized system. The results show no appreciable changes in the sensitivity and accuracy of the methodology being other available application of this work.
       
  • IMPURITY PROFILING OF DRUGS TOWARDS SAFETY AND EFFICACY: THEORY
           AND PRACTICE

    • Abstract: Last decade has witnessed enormous changes in the studies of impurity profiling of drugs which can be reflected from pharmacopoeia and regulatory guidelines. The present review article is an attempt to provide comprehensive knowledge about various aspects and details about the impurity profiling in context with regulatory guidelines. Article also focused on isolation, separation and characterization techniques of impurities. It gives preliminary idea about applicability of virtual software used for studies on safety limit for impurities. The comprehensive information related to residual solvents, residual metals and genotoxicity studies of isolated impurities have also been incorporated into present article.
       
  • NEW SYNTHESIS METHOD TO OBTAIN A METHACRYLIC MONOMER WITH A PYRYLIUM
           GROUP

    • Abstract: Methacrylic monomers with pyrylium salt derivatives are widely used to detect nucleophilic species. A new synthesis method has been used to obtain a pyrylium salt that is trisubstituted with phenyl groups at positions 2,4, and 6. The phenyl group of the 4-position has a metacrylate group in the para-position. The new synthesis method implies the esterification of 4-hydroxybenzaldehyde, using methacrylic anhydride. The formed compound react with acetophenone to form the pyrylium derivative. The yields of both reactions are greater than those previously reported in the literature.
       
 
 
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