bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the interaction between quercetin and human serum albumin by multiple spectra, electrochemical impedance spectra and molecular modeling
Authors: Dai Jie , Zou Ting , Wang Li , Zhang Yezhong , Liu Yi 
Published: May 2014

ABSTRACTQuercetin (Qu), a flavonoid compound, exists widely in the human diet and exhibits a variety of pharmacological activities. This work is aimed at studying the effect of Qu on the bioactive protein, human serum albumin (HSA) under simulated biophysical conditions. Multiple spectroscopic methods (including fluorescence and circular dichroism), electrochemical impedance spectra (EIS) and molecular modeling were employed to investigate the interaction between Qu and HSA. The fluorescence quenching and EIS experimental results showed that the fluorescence quenching of HSA was caused by formation of a Qu–HSA complex in the ground state, which belonged to the static quenching mechanism. Based on the calculated thermodynamic parameters, it concluded that the interaction was a spontaneous process and hydrogen bonds combined with van der Waal's forces played a major role in stabilizing the Qu–HSA complex. Molecular modeling results demonstrated that several amino acids participated in the binding process and the formed Qu–HSA complex was stabilized by H‐bonding network at site I in sub‐domain IIA, which was further confirmed by the site marker competitive experiments. The evidence from circular dichroism (CD) indicated that the secondary structure and microenvironment of HSA were changed. Alterations in the conformation of HSA were observed with a reduction in the amount of α helix from 59.9% (free HSA) to 56% (Qu–HSA complex), indicating a slight unfolding of the protein polypeptides. Copyright © 2014 John Wiley & Sons, Ltd.
Electrochemiluminescent pH sensor measured by the emission potential of TiO2 nanocrystals and its biosensing application
Authors: Liu Xuan , Wang Nianyue , Zhao Wei , Jiang Hui 
Published: May 2014

AbstractThis work reports for the first time a potential‐based nano‐electrochemiluminescent (ECL) pH sensor, using anatase TiO2 nanocrystals (NCs) as the ECL probe. The first ECL peak potential of the TiO2 NCs shifted negatively with increasing pH, showing a linear range from −0.47 V (vs Ag/AgCl) at pH 3 to −1.06 V at pH 10. This phenomenon was attributed to the absorption of ‘potential‐determining ions’ of OH− on the surface of TiO2 NCs, leading to larger impedance of the electron injection. Other common ‘potential‐determining ions’, such as phosphate, induced a slight potential shift of 0.03 V at a concentration of 0.1 M. Using urease as an enzyme model, a urea biosensor was developed by the simultaneous modification of urease and TiO2 NCs on indium–tin oxide (ITO) electrodes. The biosensor, measured on the basis of the pH increase caused by the enzyme catalysis reaction, had a linear range of 0.01–2.0 mM, with a potential shift of 0.175 V. The as‐prepared pH sensor, which has simple construction procedures and acceptable sensitivity and selectivity, may provide new avenues for the construction of ECL bioanalytical methodologies. Copyright © 2014 John Wiley & Sons, Ltd.
Liquid chromatography–tandem mass spectrometric assay for the determination of vaccarin in rat plasma: application to a pharmacokinetic study
Authors: Yang Guilin , Zhang Nan , Wang Tiance , Zhang Shudong , Xu Rihao , Zhu Zhicheng , Liu Kexiang 
Published: May 2014

ABSTRACTVaccarin, a flavonoid glycoside, is considered one of the major active constituents of Vaccaria segetalis. A simple and specific liquid chromatography–tandem mass spectrometric method was developed and validated for quantifying vaccarin in rat plasma following intravenous dosing. Plasma samples were precipitated with methanol and separated on a Venusil‐C18 analytical column (2.1 × 50 mm, 5 µm particles) with gradient elution consisting of methanol and 0.1% (v/v) formic acid as the mobile phase. The detection was performed on an Agilent Triple Quad LC/MS with electrospray ionization inlet in the positive multiple reaction monitoring mode. Good linearity was achieved over the concentration range of 12.5–25,000 ng/mL (r2 > 0.99). Intra‐ and inter‐day precisions were <9.1%, and accuracy ranged from −2.8 to 8.7%. The lower limit of quantification for vaccarin was 12.5 ng/mL, and the analyte was stable under various storage conditions. This validated method was successfully applied to the preliminary pharmacokinetic studies of vaccarin following intravenous administrations of 1.21, 2.41, and 4.82 mg/kg vaccarin in rats. Copyright © 2014 John Wiley & Sons, Ltd.
Ultra‐high‐performance liquid chromatography tandem mass spectrometry method for the determination of gambogenic acid in dog plasma and its application to a pharmacokinetic study
Authors: Chen Jin Pei , Wang Dian Lei , Yang Li Li , Wang Chen Yin , Wang Shan Shan 
Published: May 2014

ABSTRACTA highly sensitive and rapid ultra‐high‐performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of gambogenic acid in dog plasma. Gambogic acid was used as an internal standard (IS). After a simple liquid–liquid extraction by ethyl acetate, the analyte and internal standard were separated on an Acquity BEH C18 (100 × 2.1 mm, 1.7 µm; Waters ) column at a flow rate of 0.2 mL/min, using 0.1% formic acid–methanol (10:90, v/v) as mobile phase. Electrospray ionization source was applied and operated in the positive ion mode. Multiple reaction monitoring mode with the transitions m/z 631.3 → 507.3 and m/z 629.1 → 573.2 was used to quantify gambogenic acid and the internal standard, respectively. The calibration curves were linear in the range of 5–1000 ng/mL, with a coefficient of determination (r) of 0.999 and good calculated accuracy and precision. The low limit of quantification was 5 ng/mL. The intra‐and inter‐day precisions (relative standard deviations) were <15%. The methodology recoveries were more than 66.63%. This validated method was successfully applied to a pharmacokinetic study after intravenous injection administration of gambogenic acid in dogs at a dose of 1 mg/kg. Copyright © 2014 John Wiley & Sons, Ltd.
PAX1/SOX1 DNA methylation and cervical neoplasia detection: a Taiwanese Gynecologic Oncology Group (TGOG) study
Authors: Lai Hung‐Cheng , Ou Yu‐Che , Chen Tze‐Chien , Huang Huei‐Jean , Cheng Ya‐Min , Chen Chi‐Hau , Chu Tang‐Yuan , Hsu Shih‐Tien , Liu Cheng‐Bin , Hung Yao‐Ching , Wen Kuo‐Chang , Yu Mu‐Hsien , Wang Kung‐Liahng 
Published: May 2014

AbstractWe aimed to determine whether PAX1/SOX1 methylation could be translated to clinical practice for cervical neoplasia detection when used alone and in combination with current cytology‐based Pap screening. We conducted a multicenter case–control study in 11 medical centers in Taiwan from December 2009 to November 2010. Six hundred seventy‐six patients were included in the analysis, including 330 in the training set and 346 in the testing set. Multiplex quantitative methylation‐specific polymerase chain reaction (PCR) was performed with a TaqMan probe system using a LightCycler 480 Real‐Time PCR System (Roche). The level of human papilloma virus (HPV) was analyzed using a Hybrid Capture 2 system (Digene). Receiver operating characteristic curves were generated to obtain the best cutoff values from the training data set. The sensitivities, specificities, and accuracies were validated in the testing set. The sensitivities for methylated (m) PAX1m and SOX1m and HPV testing for detecting CIN3+ lesions were 0.64, 0.71, and 0.89, and the specificities were 0.91, 0.77, and 0.68, respectively. Combined parallel testing of PAX1m/SOX1m tests with Pap smearing showed superior specificity (0.84/0.71 vs. 0.66, respectively) and similar sensitivity (0.93/0.96 vs. 0.97) to the combination of Pap smear results and HPV testing. Thus, combined parallel testing using Pap smears and PAX1 or SOX1 methylation tests may provide better performance than a combination of Pap smears with HPV testing in detection for cervical neoplasia.
Polyamines cause elevation of steroid 5α‐reductase mRNA levels by suppressing mRNA degradation in C6 glioma cells
Authors: Morita Kyoji , Lee Mi‐Sook , Her Song , Nishibori Naoyoshi 
Published: May 2014

AbstractPolyamines are widely distributed in living organisms, and considered to play a potential role in various cellular processes. The effects of polyamines on gene expression as well as cell proliferation have been suggested to be closely associated with the physiological and pathological functions. However, it seems necessary to investigate their potential roles in the regulation of cellular metabolism and functions. Previously, glial cells have been suggested to be involved in the protection and preservation of neuronal functions, probably through the production of neurotrophic factors in the brain. On the other hand, neuroactive 5α‐reduced steroids promote glial cell differentiation, resulting in enhancement of their ability to produce brain‐derived neurotrophic factor (BDNF). Based on these findings, polyamines are assumed to stimulate the expression of the gene encoding steroid 5α‐reductase (5α‐R), which can induce the production of neuroactive 5α‐reduced steroids in glial cells. The effects of polyamines on 5α‐R mRNA levels in C6 glioma cells were examined as a model experiment. In consequence, spermine (SPM) and spermidine (SPD), but not putrescine (PUT), have been shown to elevate 5α‐R mRNA levels without activating the 5α‐R promoter. Furthermore, SPM increased 5α‐R mRNA levels under the conditions in which the mRNA biosynthesis was inhibited. Therefore, it can be speculated that polyamines increase 5α‐R mRNA levels as a consequence of suppressing the degradation of mRNA.
Radical‐Cation Dimerization Overwhelms Inclusion in [n]Pseudorotaxanes
Authors: Nchimi‐Nono Katia , Dalvand Parastoo , Wadhwa Kuldeep , Nuryyeva Selbi , Alneyadi Shaikha , Prakasam Thirumurugan , Fahrenbach Albert C. , Olsen John‐Carl , Asfari Zouhair , Platas‐Iglesias Carlos , Elhabiri Mourad , Trabolsi Ali 
Published: May 2014

AbstractSuppression of the dimerization of the viologen radical cation by cucurbit[7]uril (CB7) in water is a well‐known phenomenon. Herein, two counter‐examples are presented. Two viologen‐containing thread molecules were designed, synthesized, and thoroughly characterized by 1H DOSY NMR spectrometry, UV/Vis absorption spectrophotometry, square‐wave voltammetry, and chronocoulometry: BV4+, which contains two viologen subunits, and HV12+, which contains six. In both threads, the viologen subunits are covalently bonded to a hexavalent phosphazene core. The corresponding [3]‐ and [7]pseudorotaxanes that form on complexation with CB7, that is, BV4+⊂(CB7)2 and HV12+⊂(CB7)6, were also analyzed. The properties of two monomeric control threads, namely, methyl viologen (MV2+) and benzyl methyl viologen (BMV2+), as well as their [2]pseudorotaxane complexes with CB7 (MV2+⊂CB7 and BMV2+⊂CB7) were also investigated. As expected, the control pseudorotaxanes remained intact after one‐electron reduction of their viologen‐recognition stations. In contrast, analogous reduction of BV4+⊂(CB7)2 and HV12+⊂(CB7)6 led to host–guest decomplexation and release of the free threads BV2(.+) and HV6(.+), respectively. 1H DOSY NMR spectrometric and chronocoulometric measurements showed that BV2(.+) and HV6(.+) have larger diffusion coefficients than the corresponding [3]‐ and [7]pseudorotaxanes, and UV/Vis absorption studies provided evidence for intramolecular radical‐cation dimerization. These results demonstrate that radical‐cation dimerization, a relatively weak interaction, can be used as a driving force in novel molecular switches.
Modified SWCNTs with Amphoteric Redox and Solubilizing Properties
Authors: Rodríguez‐Pérez Laura , García Raúl , Herranz María Ángeles , Martín Nazario 
Published: May 2014

AbstractInvited for the cover of this issue is the group of Nazario Martín at Universidad Complutense de Madrid and IMDEA Nanoscience. The image depicts how doubly functionalized single‐wall carbon nanotubes (SWCNTs) can be switched from being soluble in aqueous solutions (with a Br− counteranion) to being soluble in organic solvents (with a PF6− counteranion). Read the full text of the article at 10.1002/chem.201400183.
Multiple Ambient Hydrolysis Deposition of Tin Oxide into Nanoporous Carbon To Give a Stable Anode for Lithium‐Ion Batteries
Authors: Raju Vadivukarasi , Wang Xingfeng , Luo Wei , Ji Xiulei 
Published: May 2014

AbstractA novel ambient hydrolysis deposition (AHD) methodology that employs sequential water adsorption followed by a hydrolysis reaction to infiltrate SnO2 nanoparticles into the nanopores of mesoporous carbon in a conformal and controllable manner is introduced. The empty space in the SnO2/C composites can be adjusted by varying the number of AHD cycles. An SnO2/C composite with an intermediate SnO2 loading exhibited an initial specific delithiation capacity of 1054 mAh g−1 as an anode for Li‐ion batteries. The capacity contribution from SnO2 in the composite electrode approaches the theoretical capacity of SnO2 (1494 mAh g−1) if both Sn alloying and SnO2 conversion reactions are considered to be reversible. The composite shows a specific capacity of 573 mAh g−1 after 300 cycles, that is, one of the most stable cycling performances for SnO2/mesoporous carbon composites. The results demonstrated the importance of well‐tuned empty space in nanostructured composites to accommodate expansion of the electrode active mass during alloying/dealloying and conversion reactions.
Parenting behaviors and vagal tone at six months predict attachment disorganization at twelve months
Authors: Holochwost Steven J. , Gariépy Jean‐Louis , Propper Cathi B. , Mills‐Koonce W. Roger , Moore Ginger A. 
Published: May 2014

ABSTRACTThe authors investigated the relationships among parenting behaviors, infant vagal tone, and subsequent attachment classification. Vagal tone was assessed among 6‐month olds (n = 95) during the still‐face paradigm (SFP) via respiratory sinus arrhythmia (RSA), while attachment security and disorganization were measured at 12 months during the strange situation procedure (SSP). Infants demonstrating higher levels of RSA during the normal interaction and reunion episodes of the SFP whose mothers were also rated as negative‐intrusive exhibited higher levels of attachment disorganization at 12 months, while infants with lower RSA and mothers who were negative‐intrusive did not exhibit higher levels of disorganization. These results suggest that high levels of RSA may not be adaptive within the context of negative‐intrusive parenting. © 2014 Wiley Periodicals, Inc. Dev Psychobiol 56: 1423–1430, 2014.
The therapeutic process in psychological treatments for eating disorders: A systematic review
Authors: Brauhardt Anne , de Zwaan Martina , Hilbert Anja 
Published: May 2014

ABSTRACTObjectiveFor eating disorders, a vast number of investigations have demonstrated the efficacy of psychological treatments. However, evidence supporting the impact of therapeutic process aspects on outcome (i.e., process‐outcome research) has not been disentangled.MethodUsing the Generic Model of Psychotherapy (GMP) to organize various process aspects, a systematic literature search was conducted on psychological treatment studies for anorexia nervosa, bulimia nervosa, binge‐eating disorder, and eating disorders not otherwise specified.ResultsImproved outcomes resulted for family‐based treatment compared to individual treatment, for individual compared to group treatment, booster sessions, and positive patient expectations (GMP contract aspect); for nutritional counseling and exercising but not exposure with response prevention as adjunct interventions (therapeutic operations); for highly motivated patients and, to a lesser extent, for therapeutic alliance (therapeutic bond); as well as for rapid response and longer overall treatment duration (temporal patterns). Regarding other GMP aspects, studies on self‐relatedness were completely lacking and in‐session impacts were rarely investigated.DiscussionAs most studies assessed only a limited number of process aspects, the ability to draw conclusions about their overall impact regarding outcome is rather limited. Therefore, future process‐outcome research is needed beyond investigations of treatment efficacy for eating disorders. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2014; 47:565–584)
First Examples of Near‐Infrared Luminescent Poly(methyl methacrylate)‐Supported Metallopolymers Based on Zn2Ln‐Arrayed Schiff Base Complexes
Authors: Miao Tie‐Zheng , Feng Wei‐Xu , Zhang Zhao , Su Pei‐Yang , Lü Xing‐Qiang , Song Ji‐Rong , Fan Dai‐Di , Wong Wai‐Kwok , Jones Richard A. , Su Cheng‐Yong 
Published: May 2014

AbstractThe first examples of Wolf Type II Zn2Ln‐containing metallopolymers poly{MMA‐co‐[Zn2(L)2(4‐vp)2Ln(NO3)3]} (Ln = La, Nd, Yb, Er, Gd; H2L = N,N′‐bis(salicylidene)ethylene‐1,2‐diamine; 4‐vp = 4‐vinylpyridine; MMA = methyl methacrylate) are obtained from the controlled copolymerization of heterotrinuclear Zn2Ln‐arrayed complexes [Zn2(L)2(4‐vp)2Ln(NO3)3] (Ln = La, 1; Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4; Ln = Gd, 5) with MMA. The strong and characteristic near‐infrared (NIR) luminescent Ln3+‐centered emission for each of the PMMA‐supported poly{MMA‐co‐[Zn2(L)2(4‐vp)2Ln(NO3)3]} (Ln = Nd, Yb, Er) hybrid materials is retained with somewhat higher intrinsic quantum yields than those of the respective Zn2Ln‐arrayed complex. Especially for poly(MMA‐co‐3), which has more efficient sensitization from both ligand‐centered singlet (1LC) and triplet (3LC) states of the chromophores, the concentration self‐quenching of Yb3+‐based NIR luminescence could be effectively prevented.
Experimental and theoretical insights into photochemical transformation kinetics and mechanisms of aqueous propylparaben and risk assessment of its degradation products
Authors: An Taicheng , Fang Hansun , Li Guiying , Wang Shilong , Yao Side 
Published: May 2014

Abstract

The kinetics and mechanisms of ultraviolet photochemical transformation of propylparaben (PPB) were studied. Specific kinetics scavenging experiments coupled with quantum yield determinations were used to distinguish the roles of various reactive species induced by self-sensitized and direct photolysis reactions, and the excited triplet state of PPB (3PPB*) was identified as the most important species to initiate the photochemical degradation of PPB in aquatic environments. The computational results of time-resolved absorption spectra proved that 3PPB* is a highly reactive electron acceptor, and a head-to-tail hydrogen transfer mechanism probably occurs through electron coupled with proton transfer. Physical quenching by, or chemical reaction of 3PPB* with, O2 was confirmed as a key step affecting the initial PPB transformation pathways and degradation mechanisms. The transformation products were identified and the toxicity evolutions of PPB solutions during photochemical degradation under aerobic and anaerobic conditions were compared. The results indicate that anaerobic conditions are more likely than aerobic conditions to lead to the elimination and detoxification of PPB but less likely to lead to PPB mineralization. Environ Toxicol Chem 2014;33:1809–1816. © 2014 SETAC
A phenomenological study to explore the experiences of Ugandan women that have undergone transvaginal ultrasound
Authors: Mubuuke Aloysius Gonzaga 
Published: May 2014

AbstractIntroductionTransvaginal ultrasound (TVUS) is an important examination of the female pelvis that involves the transducer being inserted into the vagina to obtain more detailed images of the pelvic organs. Unfortunately, this examination has received mixed experiences from the women who have undergone it. This study set out to explore the lived experiences of Ugandan women who have undergone TVUS.MethodsIt was a phenomenological exploratory study involving 20 women in Uganda that had previously undergone TVUS. Data were collected using in‐depth individual interviews. The responses from the women were audio‐recorded and later transcribed. Thematic analysis was used to interpret and make meaning of the data collected.ResultsAnalysis of data revealed mostly negative experiences of the women who were included in this study. Key words from the participating women that illustrated the negative experiences included: fear, vulnerability, guilt, anxiety and embarrassment. It was also observed that these initial negative experiences are likely to reduce the women's acceptability and compliance to TVUS even when it is needed for better clinical management. Data were categorised into the following three thematic areas: (1) broken communication, (2) anxiety and discomfort and (3) cultural influence.ConclusionWomen in this study portrayed negative experiences of undergoing TVUS. Key suggestions like informed consent are recommended to improve compliance of the women to this type of procedure.
Spatiotemporal assessment of dust loading over the United Arab Emirates
Authors: Gherboudj Imen , Ghedira Hosni 
Published: May 2014

ABSTRACTEvaluation of the spatiotemporal distribution of dust loading over the UAE is a great challenge because of its dependence on many climatic parameters and surface features. Indeed, the region has the world's largest confluences of natural and anthropogenic dust emissions. Those being the case, ground‐based and remotely sensed data are used conjointly to characterize the dust loading at both local and large scales. The ground‐based measurements comprise AERONET aerosol optical properties measurements represented by the aerosol optical thickness (AOT870) and Angstrom component (α500/870) collected at high temporal resolution between 2004 and 2007 over several stations. The remotely sensed data consists of diffuse horizontal irradiance (DHI) estimated from retrieved MSG/SEVRI images using Helioclim‐III (CEP: Centre for Energy and Processes, MINES ParisTech) or Artificial Neural Network (ReCREMA: Research Center for Renewable Energy Mapping and Assessment, MASDAR Institute) from 2004 to 2010 over the same locations. On correlating the monthly average DHI estimates to the monthly AOT870 measurements, higher correlation was found with the ReCREMA products rather compared to the Helioclim‐III products. Therefore, the monthly AOT870 and α500/870 values have been retrieved from the available DHI estimates over the United Arab Emirates (UAE). The resulting maps offer a clear guide to patterns of the monthly dust severity variability. Temporally, the dust loading occur mainly during the March–May/June–August (MAM/JJA) period where the obtained monthly AOT870 and Angstrom component (α500/870) can both reach an approximate value of ∼0.6. Spatially, the dust loading over the region follow the climatic parameters with almost homogeneous distribution expected between May and July where AOT870 and α500/870 exhibit high large‐scale spatial variability. On the basis of the European Centre for Medium‐Range Weather Forecasts (ECMWF) and ground‐based wind speed and direction data, the dust blows mainly from the southwest/southeast and the northeast sides.