bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Dynamics Simulation of Diffusion of Vitamin C in Water Solution
Authors: Zeng Jianping , Wang Aimin , Gong Xuedong , Chen Jingwen , Chen Song , Xue Feng 
Published: January 2012

AbstractUnder different temperatures and concentrations, the diffusion of Vitamin C (VC) in water solution was examined by molecular dynamics simulation. The diffusion coefficients were calculated based on the Einstein equation. The influences of temperature, concentration, and simulation time on the diffusion coefficient were discussed. The results showed that at higher temperature and lower concentration the normal diffusions appear relatively late, but the linear range of mean square displacement curves continues longer than that at lower temperature and higher concentration. At the same temperature, the normal diffusion time increases and the diffusion coefficient decreases as the simulation concentration increases. These simulation results are in good agreement with experiments. Analyses of the pair correlation functions of the simulation systems showed that hydrogen bonds are mainly formed between the hydrogen atoms of VC molecules and oxygen atoms of H2O molecules, rather than between the O atoms of VC molecules and H atoms of H2O molecules. The diffusion coefficient is higher as the interaction between water molecules and VC molecules is stronger when VC concentration is lower. The water in the model systems affects the diffusion of VC molecules by the short‐range repulsion of O(H2O)‐O(H2O) pairs and the non‐bond interaction of H(H2O)‐H(H2O) pairs. The short‐range repulsion of O(H2O)‐O(H2O) pairs is greater when VC concentration is higher, the diffusion of VC is weaker. The greater the non‐bond interaction of H(H2O)‐H(H2O) pairs is, the higher the VC diffusion is. It is expected that this study can provide a theoretical direction for the experiments on the mass transfer of VC in water solution.
A Novel Sandwich‐type Dinuclear Complex for High‐capacity Hydrogen Storage
Authors: Zhu Haiyan , Chen Yuanzhen , Li Sai , Cao Xiuzhen , Liu Yongning 
Published: January 2012

AbstractFrom density functional theory (DFT) calculations, we predicted that the sandwich‐type dinuclear organometallic compounds Cp2Ti2 and Cp2Sc2 can adsorb up to eight hydrogen molecules respectively, corresponding to a high gravimetric storage capacity of 6.7% and 6.8% (w), respectively. These sandwich‐type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen at ambient conditions.
Preparation of Mesoporous 1,4‐Phenylene‐silica Nanorings through a Dual‐templating Approach
Authors: Zhu Weike , Li Baozong , Bi Lifeng , Wang Sibing , Zhuang Wei , Li Yi , Yang Yonggang 
Published: January 2012

AbstractMesoporous 1,4‐phenylene‐silica nanorings were prepared using cetyltrimethylammonium bromide (CTAB) and (S)‐2‐methyl‐1‐butanol as a chiral dopant in concentrated aqueous NH3 solutions. Transmission electron microscopy images of the samples indicated that the nanorings were formed by bending nanorods 360°. With increasing the stirring speed or the (S)‐2‐methyl‐1‐butanol/CTAB molar ratio, the morphologies of mesoporous 1,4‐phenylene‐silicas changed from helical nanofibers to nanorings, and then to nano‐saddles. Circular dichroism spectra of these hybrid silicas indicated that they were chiral.
Spectrofluorimetric and Spectrophotometric Stability‐Indicating Methods for the Analysis of Veralipride in Presence of Its Degradants and in Spiked Human Plasma
Authors: Salama Nahla Nour El Din Ahmed , Salem Maissa Yacoub , Abd El Halim Lobna Mohammed , Abdel Fattah Laila El‐Sayed 
Published: January 2012

AbstractSpectrofluorimetric and spectrophotometric stability‐indicating methods were developed and validated for analysis of veralipride (Ver) in presence of its hydrolytic and oxidative degradants. The spectrofluorimetric method was based on direct measurement of the intrinsic fluorescence of Ver at 366 nm after excitation at 299 nm using sodium lauryl sulfate (SLS) as micelle enhancer. The fluorescence intensity plot was linear over the concentration range 1.0–10.0 µg·mL−1. The high sensitivity of the method allowed its successful application to the analysis of Ver in spiked human plasma. Two other methods were developed. They are based on the oxidative coupling reaction of Ver with 3‐methyl benzothiazolin‐2‐one hydrazone (MBTH) hydrochloride in presence of ceric ammonium sulphate in an acidic medium. The first method depends on spectrophotometric measurement of the stable green colored oxidative coupling product at 660 nm. The different experimental parameters affecting the reaction were optimized. Linearity range is 10.0–100.0 µg·mL−1. The second method depends on a fluorescence quenching effect of Ver on the fluorescence of Ce3+. The difference in fluorescence intensity was measured at 380 nm after excitation at 300 nm. This method is applicable over the concentration ranges 0.25–2.50 µg·mL−1. The methods were validated according to the ICH guidelines. They were successfully applied for the analysis of Ver in drug substance, drug product and in laboratory prepared mixtures containing different percentages of hydrolytic and oxidative degradants.
Kinetics of the Reaction of 2‐Chloro‐3,5‐dinitrobenzotriflouride with Aniline in Toluene and Methanol‐Toluene Mixed Solvents
Authors: Fathalla Magda F. 
Published: January 2012

AbstractKinetics of the reaction of 2‐chloro‐3,5‐dinitrobenzotriflouride with aniline were studied in toluene, methanol‐toluene binary solvents, benzene and chloroform. The reaction in toluene exhibits third‐order kinetics consistent with aggregates of aniline. Thermodynamic parameters (H#, (S# and (G#are calculated and discussed for the reaction of 2‐chloro‐3,5‐dinitrobenzotriflouride with aniline in methanol‐toluene. Molecular complexes between aniline and the substrate are rejected spectrophotometricaly. The mechanism is studied and compared with the reaction in presence of pyridine. It shows an amine dependence and formation of homo and/or hetero mixed aggregates between aniline and pyridine i.e. dimer mechanism.
Environmental and Health Impacts of Successive Mineral Fertilization in Egypt
Authors: Abdelhafez Ahmed A. , Abbas Hassan H. , Abd‐El‐Aal Rafat S. , Kandil Nabil F. , Li Jianhua , Mahmoud Wahballah 
Published: January 2012

AbstractExcessive amounts of mineral fertilizers are unnecessarily applied to agricultural soils in Egypt to increase crop yield. The current study aims at assessing the impacts of fertilization with different mineral fertilizers for different cultivation periods on the accumulation of heavy metals in soils and plants grown thereon. In addition, human risks resulted due to the exposure to these metal ions through ingestion, and dermal routes were evaluated. Soil and plant samples were collected from several locations in El‐Behira Governorate, Egypt and their heavy metal contents were measured. The result indicated that there is a continuous accumulation of heavy metals in the soils and the plants grown thereon. Calculation of the hazard index (HI) revealed that humans, especially children, have a potential health risk for both Pb and Cd, which have levels greater than the safe level (1). Finally, the obtained results showed that the continuous application of mineral fertilizers containing high levels of heavy metals pose a potential health threat.
Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat
Authors: Izquierdo Marta , Marzal Paula , Gabaldón Carmen , Silvetti Margherita , Castaldi Paola 
Published: January 2012

AbstractA systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake (qmax) at pH 6 of 85.78 and 49.69 mg g−1, for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO3)2, and EDTA was applied to copper‐saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of copper(II) sorption was obtained by desorption with HCl and SD. Fourier transform IR spectroscopy (FTIR) analysis detected the presence of peaks associated with OH groups in aromatic and aliphatic structures, CH, CH2, and CH3 in aliphatic structures, COO− and COOH groups and unsaturated aromatic structures on the surface of both biosorbents, as well as peaks corresponding to SiO groups on the surface of peat. The results of SEM‐EDX and FTIR analysis of copper‐saturated samples demonstrated that ion exchange was one of the mechanisms involved in copper(II) retention. Thermal analysis of biosorbent samples showed that copper(II) sorption–desorption processes affected the thermal stability of the biosorbents.
Brainstem origins of glutamatergic innervation of the rat hypothalamic paraventricular nucleus
Authors: Ziegler Dana R. , Edwards Monica R. , Ulrich‐Lai Yvonne M. , Herman James P. , Cullinan William E. 
Published: January 2012

AbstractMultiple lines of evidence document a role for glutamatergic input to the hypothalamic paraventricular nucleus (PVH) in stress‐induced activation of the hypothalamic‐pituitary‐adrenocortical (HPA) axis. However, the neuroanatomical origins of the glutamatergic input have yet to be definitively determined. We have previously shown that vesicular glutamate transporter 2 (VGLUT2) is the predominant VGLUT isoform expressed in the basal forebrain and brainstem, including PVH‐projecting regions, and that the PVH is preferentially innervated by VGLUT2‐immunoreactive terminals/boutons. The present study employed a dual‐labeling approach, combining immunolabeling for a retrograde tract tracer, Fluoro‐Gold (FG), with in situ hybridization for VGLUT2 mRNA, to map the brainstem and caudal forebrain distribution of glutamatergic PVH‐projecting neurons. The present report presents evidence for substantial dual labeling in the periaqueductal gray, caudal portions of the zona incerta and subparafascicular nucleus, and the lateral parabrachial nucleus. The current data also suggest that relatively few PVH‐projecting neurons in ascending raphe nuclei, nucleus of the solitary tract, or ventrolateral medulla are VGLUT2 positive. The data reveal multiple brainstem origins of glutamatergic input to PVH that are positioned to play a role in transducing a diverse range of stressful stimuli. J. Comp. Neurol. 520:2369–2394, 2012. © 2012 Wiley Periodicals Inc.
The Clean Development Mechanism in China: Institutional Perspectives on Governance
Authors: Buhr Katarina , Thörn Philip , Hjerpe Mattias 
Published: January 2012

ABSTRACTThe Clean Development Mechanism (CDM) has grown into a central feature of the global carbon market. Besides a range of normative and evaluative research into the CDM, scholars have applied international relations perspectives in which the CDM has been analysed as an example of global governance, engaging multiple actors across administrative levels. This paper focuses on a national government and how its activities affect the CDM market. We draw on an empirical case study of China to demonstrate how governmental action can be understood in light of national institutional factors, defined as normative, cognitive or regulative elements. The paper describes and explains the extensiveness of Chinese government action regarding the CDM and discusses its consequences for the market. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Fabrication of a 3D Hierarchical Flower‐Like MgO Microsphere and Its Application as Heterogeneous Catalyst
Authors: Qu Yang , Zhou Wei , Ren Zhiyu , Pan Kai , Tian Chungui , Liu Yang , Feng Shanshan , Dong Youzhen , Fu Honggang 
Published: January 2012

AbstractA 3D hierarchical flower‐like MgO microsphere was successfully obtained by pyrolysis of the flower‐like Mg5(CO3)4(OH)2·4H2O microsphere precursor which was itself synthesised by means of a facile and environmentally friendly hydrothermal route from MgCl2·6H2O. The possible formation process of the microsphere precursor was systematically investigated and considered to result from the following steps: (i) forming the 1D pillar‐like MgCO3; (ii) cracking to a 2D flake structure; (iii) assembling to the 3D flower‐like Mg5(CO3)4(OH)2·4H2O microsphere. The obtained close‐packed 3D flower‐like MgO microsphere has cubic symmetry and high crystallinity assembled by nanoflake particles with a mean diameter of 10 μm. Moreover, the heterogeneous catalysis of the Claisen–Schmidt condensation reaction between benzaldehyde and acetophenone to synthesise chalcones was also studied. The 3D flower‐like MgO microsphere exhibited better catalytic performance than that of commercial MgO and this was attributed to the especially 3D hierarchical flower‐like structure and the large surface area.
Zinc and nickel determination in liquid edible oils by FAAS after the extraction
Authors: Baran Eda Köse , Yaşar Sema Bağdat 
Published: January 2012

AbstractA new method has been developed for the extraction and determination of zinc and nickel in liquid edible oils by using the complexation of these metals with [N,N′‐bis(salicylidene)‐2,2′‐dimethyl‐1,3‐propanediaminato]. Zn(II) and Ni(II) complexes with a tetradentate Schiff base have been investigated spectrophotometrically. Experimental extraction conditions for these metals from liquid oil standards were optimized using central composite design. Optimum conditions for Zn(II) and Ni(II) extractions from oil have been found close to each other. The ratio of the volume of used Schiff base solution to the amount of oil (VLDM/moil; mL/g), the stirring time and the temperature were round about 1.00 mL/g, 55 min, 32°C, respectively, for simultaneous determination of both metals in same sample. The recovery percentages at the optimum experimental conditions were found 98.9 ± 2.8 and 101.8 ± 4.7 for Zn(II) and Ni(II), respectively. The proposed method was applied on the raw and spiked samples such as olive oil, sunflower oil, corn oil, canola oil and obtained recovery values were between 93.7–107.2 and 93.1–101.1% for Zn(II) and Ni(II), respectively.Practical applications: There is interest in the determination of metals in liquid edible oils because of their catalytic effect on the oxidation reaction of oils. A new method for the determination of Zn(II) and Ni(II) in liquid edible oils which does not require any digestion or decomposition was developed. This study offeres a cheap, rapid, accurate, sensitive, risk‐free, and practical metal determination method after the extraction.
Phenolic composition of virgin olive oils from cross breeding segregating populations
Authors: El Riachy Milad , Priego‐Capote Feliciano , Rallo Luis , Luque‐de Castro María Dolores , León Lorenzo 
Published: January 2012

AbstractThe evaluation and characterization of segregating populations is a critical step in olive breeding programs. In this work, phenolic profiles of virgin olive oils (VOOs) from segregating populations obtained by cross breeding in Cordoba (Spain) have been evaluated. Genotypes obtained from open pollination of the cultivar Manzanilla de Sevilla, and from crosses between the cultivars Arbequina × Arbosana, Picual × Koroneiki and Sikitita × Arbosana were tested. The phenolic composition was determined after liquid–liquid extraction with 60:40 v/v methanol–water and subsequent chromatographic analysis with ultraviolet (UV) detection of both absorption and fluorescence in a sequential configuration. Results for all studied compounds showed high degree of variability between genotypes, with a higher range of variation than the observed for the genitors. Most of the observed variability was attributable to differences in genotypes within crosses rather than among crosses. Some issues related to breeding strategies are discussed.Practical applications: Phenolic compounds are considered to be of paramount importance for the assessment of virgin olive oil quality due to their contribution to the nutraceutical and sensory profile of this natural food. This study focuses on the evaluation of the content of phenolic compounds in olive oils originated from cross breeding in an olive breeding program (Cordoba, Spain). This step is crucial to determine the range of variation of phenolic compounds and the selection of interesting genotypes with higher composition in total phenols or in an individual phenol targeted at a breeding program.
Virgin olive oil in preventive medicine: From legend to epigenetics
Authors: Caramia Giuseppe , Gori Alessandro , Valli Enrico , Cerretani Lorenzo 
Published: January 2012

AbstractAmong vegetable oils, extra virgin olive oil (EVOO) has nutritional and sensory characteristics that make it unique and a basic component of the Mediterranean diet. EVOO has always been used over the centuries for its preventive and therapeutic properties, as well as precious and valuable dietary lipidic condiment. Benefic effects of a diet rich in EVOO on the human health, especially in prevention and/or reduction of hypercholesterolaemia, serum lipoprotein levels and atherosclerosis, hypertension, cardiovascular diseases and thrombotic risk, oxidation and oxidative stress, obesity and type 2 diabetes, inflammatory processes and cancer are discussed in these review. Recent studies suggest also its role in regulating the sense of satiety. The chemical compounds of EVOO that may contribute to its overall therapeutic characteristics, the epigenetic and physiological mechanisms involved are focused, taking into account the most important studies in the literature of the last years.Practical applications: Many studies on various aspects of nutrition indicated that many human diseases are influenced by lifestyle, in which the diet has an important aspect. The use of extra virgin olive oil is especially important from early childhood and throughout adult life to contribute to hinder the aging process. The importance of preventive and sometimes curative action, carried out by its various components in several pathological conditions has emerged from clinical, experimental, and epidemiological studies which, in many cases, are accompanied by indisputable scientific evidences. Taking into account the most important studies in the literature of the last years, the chemical compounds of extra virgin olive oil and the physiological mechanisms involved in their curative/health effects are the focus of this article.
Simultaneous quantification of serum phytosterols and cholesterol precursors using a simple gas chromatographic method
Authors: García‐Llatas Guadalupe , Vidal Carmen , Cilla Antonio , Barberá Reyes , Lagarda María Jesús 
Published: January 2012

AbstractDetermination of the main phytosterols (Ps, β‐sitosterol and campesterol) and cholesterol precursors (desmosterol and lathosterol) in human serum using a simple GC‐FID method has been validated. Direct saponification, without lipid extraction, sterols extraction, and further derivatization was applied to samples prior to GC analysis. To evaluate the method, a pool of serum samples from eight healthy women was used. Good linearity (r>0.99) was found in the assay range: β‐sitosterol (0.99–17.82 µg/mL), campesterol (0.14–10.8 µg/mL), desmosterol (0.17–2.6 µg/mL), and lathosterol (0.6–5.97 µg/mL). Limits of detection (ng/mL) were: 86 (β‐sitosterol), 42 (campesterol), 4 (desmosterol), and 44 (lathosterol). Accuracy, estimated by recovery assays (%), were: 113 (β‐sitosterol), 114 (campesterol), 111 (desmosterol), and 102 (lathosterol). Within and between precision values (%), expressed as the relative SD (RSD), were: 2.6 and 8.1 (β‐sitosterol), 1.6 and 7.2 (campesterol), 2.1 and 7.9 (desmosterol), and 4.1 and 5.8 (lathosterol), respectively. The developed methodology allowed fast (1‐day analysis) and reliable quantification of sterols in serum, required a small volume of sample and reduced use of solvents. It therefore could be used in clinical assays for the determination of serum sterols, as in evaluating the pharmacological response to lipid‐lowering agents, and in assessing biological responses to Ps‐enriched diets.Practical applications: This methodology allows fast and reliable quantification of sterols in serum, requiring a small volume of sample and reduced use of solvents. It can be used as a routine method for the quantification of phytosterols and cholesterol precursors in clinical assays, and it is also suitable for monitoring biological responses to health‐promoting phytosterol‐enriched diets.
Palladium‐Catalyzed Tandem Reactions of β‐(2‐Bromophenyl)‐α,β‐Unsaturated Carbonyl Compounds with 2‐Hydroxyphenylboronic Acid: A New Route to Benzo[c]chromenes
Authors: Zhu Qihua , Wang Xuyan , Xu Yungen 
Published: January 2012

AbstractPalladium‐catalyzed tandem reactions of β‐(2‐bromophenyl)‐α,β‐unsaturated carbonyl compounds with 2‐hydroxyphenylboronic acid for the synthesis of benzo[c]chromenes are presented. This mild reaction allows formation of onecarbon–carbon bond and one carbon–oxygen bond in one pot.
Investigation of a Biosensor Based on Phenylalanine Dehydrogenase Immobilized on a Polymer‐Blend Film for Phenylketonuria Diagnosis
Authors: Naghib Seyed Morteza , Rabiee Mohammad , Omidinia Eskandar , Khoshkenar Payam 
Published: January 2012

AbstractWe investigated aL‐phenylalanine (L‐phe) biosensor, functionalized through enzyme immobilization on a polymer‐blend film. The electron mediator 3,4‐dihydroxybenzaldehyde (3,4‐DHB) was employed at the electrode surface to improve direct oxidation of NADH to NAD+and no additional reagents is required to be added to the sample solution. The bioactivated electrode was coated with a semi‐permeable cellulose acetate membrane in order to prevent dissolution of biofunctionalized polymer‐blend film. This constructed enzyme electrode is the first selective biosensor for phenylketonuria (PKU) detection. The sensitivity of the enzyme electrode was determined as 12.014 mA/M cm2. The Michaelis–Menten and current responses as well as sensitivity of the electrode showed improved values than those of previous works. This selective biosensor presented an excellent electroanalytical response forL‐phe, with a high steady‐state current being obtained after 20 s. The sensitivity of our biodevice is quite sufficient for the purpose of PKU detection because the reference range of clinical concern forL‐phenylalanine concentration isCL‐phe>0.5 mM. This surface‐bioactivated enzyme electrode retained more than 80 % of its electrocatalytic activity after 16 days.
DNA – Cyanobacterial Hepatotoxins Microcystin‐LR and Nodularin Interaction: Electrochemical Evaluation
Authors: Santos Paulina V. F. , Lopes Ilanna C. , Diculescu Victor C. , Oliveira‐Brett Ana Maria 
Published: January 2012

AbstractMicrocystin‐LR (MC‐LR) and nodularin (NOD), two potent cyanotoxins with strong hepatotoxic, genotoxic and carcinogenic potential have been associated with the induction of deoxyribonucleic acid (DNA) damage in vitro and in vivo. Electrochemical studies were performed to understand the DNA interaction mechanisms with MC‐LR and NOD using a dsDNA‐electrochemical biosensor and incubated solutions. The decrease of the dsDNA oxidation peaks with increasing incubation time due to aggregation of DNA strands and the liberation of adenine free residues, causing the occurrence of DNA abasic sites, was observed, which may introduce mutations in the dsDNA during the replication process.