bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined effect of relative humidity and temperature on dynamic viscoelastic properties and glass transition of poly(vinyl alcohol)
Authors: Hu Hongjiu , Zhang Xiaolong , He Yaolong , Guo Zhan‐sheng , Zhang Junqian , Song Yicheng 
Published: June 2013

ABSTRACTOn the basis of the experimental studies on viscoelastic properties of poly vinyl alcohol (PVA) films at various relative humidity (RH) and temperature conditions by dynamic mechanical analysis (DMA), the influence of both temperature and RH on the glass transition are discussed and an improved property model is developed to relate the dynamic modulus to RH and temperature. The results indicate that (1) with increasing the RH, the storage modulus of PVA decrease remarkably, while both loss modulus and tanδ sharply increase to reach the peak and then markedly drops. The intensity of this variation is highly dependent upon temperature. (2) Moisture increase will cause the glass transition of PVA at isothermal condition and the transition point can be detected by glass transition relative humidity (RHg) that obtained by isothermal RH scans. (3) Similar to the relationship between Tg and RH, the RHg of PVA vary linearly with temperature. The state diagram of RHg versus temperatures is nearly consistent with that of Tg versus RH. (4)The present equation based on model of Mahieux and Reifsnider (Mahieux and Reifsnider, Polymer 2001, 42, 3281) can predict well the dynamic modulus of PVA at various RHs and temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3161–3167, 2013
Effects of type of binder and conducting phase on the performance of solid‐state electrochemiluminescence composites
Authors: Safavi A. , Sedaghati F. , Shahbaazi H. 
Published: June 2013

ABSTRACTThe electrochemiluminescence (ECL) of tris(2,2‐bipyridyl)ruthenium [Ru(bpy)3]2+ has received much attention. By immobilizing [Ru(bpy)3]2+ on an electrode surface, solid‐state ECL has several advantages over solution‐phase ECL, such as reduced amounts of costly reagent and a simplified experimental design. Herein, different types of solid‐state ECL sensors were fabricated and the performances of paraffin oil and two ionic liquids (ILs) as the binders were compared for the construction of solid‐state ECL. Scanning electron microscopy (SEM), CCD camera, UV–vis, fluorescence spectroscopy, electrochemistry and ECL were applied to characterize and evaluate the performance of the solid‐state composites. According to the obtained results, Ru–graphite/IL octyl pyridinium hexaflurophosphate (OPPF6) was introduced as a new solid‐state ECL with excellent properties such as simple preparation, low background current, fast electron‐transfer rate and good reproducibility and stability. Moreover, for a study of the effect of carbon structure on the performance of the electrode, graphite was replaced by multi‐walled carbon nanotubes (MWCNTs) and Ru–MWCNT/OPPF6 was constructed and its efficiency was compared with Ru–graphite/OPPF6 composite electrode. Copyright © 2013 John Wiley & Sons, Ltd.
Exploration of Sialic Acid Diversity and Biology Using Sialoglycan Microarrays
Authors: Deng Lingquan , Chen Xi , Varki Ajit 
Published: June 2013

ABSTRACTSialic acids (Sias) are a group of α‐keto acids with a nine‐carbon backbone, which display many types of modifications in nature. The diversity of natural Sia presentations is magnified by a variety of glycosidic linkages to underlying glycans, the sequences and classes of such glycans, as well as the spatial organization of Sias with their surroundings. This diversity is closely linked to the numerous and varied biological functions of Sias. Relatively large libraries of natural and unnatural Sias have recently been chemically/chemoenzymatically synthesized and/or isolated from natural sources. The resulting sialoglycan microarrays have proved to be valuable tools for the exploration of diversity and biology of Sias. Here we provide an overview of Sia diversity in nature, the approaches used to generate sialoglycan microarrays, and the achievements and challenges arising. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 650–665, 2013.
Solution Phase Conformation and Proteolytic Stability of Amide‐Linked Neuraminic Acid Analogues
Authors: Saludes Jonel P. , Gregar Travis Q. , Monreal I. Abrrey , Cook Brandan M. , Danan‐Leon Lieza M. , Gervay‐Hague Jacquelyn 
Published: June 2013

ABSTRACTAmide‐linked homopolymers of sialic acid offer the advantages of stable secondary structure and increased bioavailability making them useful constructs for pharmaceutical design and drug delivery. Defining the structural characteristics that give rise to secondary structure in aqueous solution is challenging in homopolymeric material due to spectral overlap in NMR spectra. Having previously developed computational tools for heteroologomers with resolved spectra, we now report that application of these methods in combination with circular dichroism, NH/ND NMR exchange rates and nOe data has enabled the structural determination of a neutral, δ‐amide‐linked homopolymer of a sialic acid analogue called Neu2en. The results show that the inherent planarity of the pyranose ring in Neu2en brought about by the α,δ‐conjugated amide bond serves as the primary driving force of the overall conformation of the homooligomer. This peptide surrogate has an excellent bioavailability profile, with half‐life of ∼12 h in human blood serum, which offers a viable peptide scaffold that is resistant to proteolytic degradation. Furthermore, a proof‐of‐principle study illustrates that Neu2en oligomers are functionalizable with small molecule ligands using 1,3‐dipolar cycloaddition chemistry. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 686–696, 2013.
Visualization of the leakage of pancreatic juice using a chymotrypsin-activated fluorescent probe
Authors: Yamashita S , Sakabe M , Ishizawa T , Hasegawa K , Urano Y , Kokudo N 
Published: June 2013

Abstract

Background
Pancreatic fistula (PF) remains the most serious complication after digestive surgery. It is difficult to prevent because of the inability to visualize the leakage of pancreatic juice during surgery or to evaluate the protease activity of leaked fluid, which is responsible for PF formation.

Methods
The fluorescence intensities of a chymotrypsin probe (glutamyl-phenylalanine hydroxymethyl rhodamine green with added trypsin) in pancreatic juice and in intestinal or abdominal fluids drained after pancreatic resection were evaluated. The chymotrypsin probe was sprayed on to filter papers that had been placed on the resected pancreatic stump in patients undergoing pancreaticoduodenectomy or central pancreatectomy. The ability of this technique to visualize the leakage of pancreatic juice and predict postoperative PF formation was assessed.

Results
The fluorescence intensity of the chymotrypsin probe in 76 fluid samples correlated positively with amylase levels (rs = 0·678, P &lt; 0·001). The fluorescence patterns of the pancreatic stump were classified grossly into the three types: duct (fluorescence signal visualized only on the stump of the main pancreatic duct, 16 patients), diffuse (ductal stump and surrounding pancreatic parenchyma, 7) and negative (no fluorescence signal, 7). Symptomatic PFs developed in 13 of 23 patients with duct- or diffuse-type fluorescence, but in none of the seven patients with negative-type fluorescence (P = 0·008).

Conclusion
The chymotrypsin probe enabled determination of the protease activity in drained pancreatic fluid samples and allowed real-time visualization of pancreatic juice leakage during surgery.
Comparative study on the excretion of vitexin‐4′′‐O‐glucoside in mice after oral and intravenous administration by using HPLC
Authors: Cai Shuang , Chen Yinghui , Zhang Wenjie , Ying Xixiang 
Published: June 2013

ABSTRACTThe aim of the present study was to characterize the excretion of pure vitexin‐4”‐O‐glucoside (VOG) in mice following oral and intravenous administration at a dose of 30 mg/kg. A sensitive and specific HPLC method with hespridin as internal standard, a Diamonsil C18 column protected with a KR C18 guard column and a mixture consisting of methanol–acetonitrile–tetrahydrofuran–0.1% glacial acetic acid (6:2:18:74, v/v/v/v) as mobile phase was developed and validated for quantitative analysis in biological samples. VOG could be excreted as prototype in excreta including urine and feces after both routes of administration, and the cumulative excretion of VOG was 24.31 ± 11.10% (17.97 ± 5.59% in urinary excretion; 6.34 ± 5.51% in fecal excretion) following oral dosing and 5.66 ± 3.94% (4.78 ± 3.13% in urinary excretion; 0.88 ± 0.81% in fecal excretion) following intravenous dosing. The results showed that the elimination of VOG after the two routes was fairly low, which meant that VOG was metabolized as other forms and the elimination after oral dosing was almost 4.3‐fold that after intravenous dosing. For both routes of administration, VOG excreted as prototype in urine was much more than that in feces, nearly 2.83‐fold for oral administration and 5.43‐fold for intravenous administration, which should be attributed to enterohepatic circulation. Taken together, renal excretion was the dominant path of elimination of VOG for oral and intravenous administration in mice and biliary excretion contributed less. Copyright © 2013 John Wiley & Sons, Ltd.
A simple and accurate method to determine nitrite and nitrate in serum based on high‐performance liquid chromatography with fluorescence detection
Authors: Shu‐yu Zhan , Qing Shao , Li Liu , Xiao‐hui Fan 
Published: June 2013

ABSTRACTA simple method for accurate determination of nitrite and nitrate in serum was proposed to avoid the variation of nitrate reduction. For nitrite determination, serum samples were directly precipitated with methanol pre‐nitrate conversion, and then the supernatant reacted with 2,3‐diaminonaphthalene (DAN) to form 2,3‐naphthotriazole (NAT), which was quantitatively analyzed by high‐performance liquid chromatography coupled with fluorescence detection (HPLC‐FL). For nitrate determination, samples were firstly heated at 70°C for 10 min to inactivate endogenous reductase‐inhibiting proteins, then nitrate in the samples was quantitatively reduced to nitrite by reductase added experimentally. The difference in total nitrite concentrations between pre‐ and post‐nitrate conversion was used to calculate the amount of nitrate in the samples. In addition to good specificity, high sensitivity, satisfactory accuracy and reproducibility, our method is simple and suitable for the quantitative determination of nanomolar level of nitrite and nitrate in a large number of serum samples. Copyright © 2013 John Wiley & Sons, Ltd.
Post‐separation Fathering and Domestic Abuse: Challenges and Contradictions
Authors: Holt Stephanie 
Published: June 2013

This paper explores the experience of post‐separation fathering, in the context of a prior history of domestic abuse from the perspectives of mothers, fathers, children and professionals participating in a three‐year doctoral research project. A mixed methodological research design conducted over two phases involved both the completion of survey questionnaires by 219 mothers and the participation in focus groups and individual interviews by children and young people, mothers, fathers and professionals. The findings highlight clear evidence of post‐separation contact facilitating the continued abuse of women and children. The findings also highlight a lack of attention to the parenting of abusive men who were identified as struggling to realise their fathering aspirations and take responsibility for the impact of their abusive behaviour on their children and ex‐partners. Particular constructions of family life are found to sustain the often unmonitored presence of abusive men in post‐separation family life. This paper concludes by asserting the need to prioritise the construction of fathers as ‘risk’ in the context of post‐separation father‐child contact. Doing so does not mean excluding fathers from children's lives; rather, what is critical is to find ways to ensure that abusive men can be ‘good enough’ fathers. Copyright © 2013 John Wiley & Sons, Ltd.‘Clear evidence of post‐separation contact facilitating the continued abuse of women and children’Key Practitioner MessagesSeparation is not a ‘vaccine against domestic violence’, with women and children at risk of continued abuse in the post‐separation period.Abusive men need to be held responsible for their abusive behaviour before the potential for safe contact can be considered.All of the key players – mothers, children and fathers – may need support from the impact that domestic violence has on parenting capacity and family life.‘Abusive men need to be held responsible for their abusive behaviour before the potential for safe contact can be considered’
Implementation of real‐time three‐dimensional transesophageal echocardiography for mitral balloon valvuloplasty
Authors: Eng Marvin H. , Salcedo Ernesto E. , Kim Michael , Quaife Robert A. , Carroll John D. 
Published: June 2013

BackgroundTransthoracic (TTE) and intracardiac echocardiography (ICE) have both been established as modalities for imaging guidance in mitral balloon valvuloplasty (MBV). Real‐time three‐dimensional transesophageal echocardiography (RT3D‐TEE) improves depth resolution, characterization of pathology and visualization of interventional catheters and devices. Three‐dimensional imaging should enhance catheter navigation but improvements in procedural outcomes are not easily quantified. Using time from transseptal puncture to balloon inflation, procedure time and radiation exposure as surrogates for improvements linked to image guidance, we describe our early experience in implementing RT3D‐TEE during MBV, a prototypical left‐sided structural intervention.MethodsUsing a dedicated interventional procedures database, we reviewed the clinical and procedural variables of 70 consecutive cases of MBV utilizing either RT3D‐TEE or TTE combined with ICE from 12/2004 to 4/2009.ResultsThe clinical characteristics of both groups were well matched and there was no difference in mean gradient reduction or complication rates. Fluoroscopy times (TTE/ICE 26.7 ± 5.6 min. vs. RT3D‐TEE 23.3 ± 6 min. P = 0.02) and radiation dose‐area product (TTE/ICE 216.2 ± 96.6 vs. RT3D‐TEE 171.5 ± 63.9) were lower with the RT3D‐TEE cohort. Time from 1st transseptal puncture attempt to 1st balloon inflation was found to be lower in the RT‐3DTEE cohort (TTE/ICE 36 ± 8 min vs. 28 ± 8 min P <0.01)ConclusionRT3D‐TEE is associated with expedited transseptal puncture and balloon catheter navigation as reflected in the decreased transseptal to balloon time. RT3D‐TEE is associated with less reliance on fluoroscopic navigation as compared to using TTE/ICE. This series demonstrates the feasibility and advantages of implementing RT3D‐TEE for MBV. © 2013 Wiley Periodicals, Inc.
Near‐Infrared‐Controlled, Targeted Hydrophobic Drug‐Delivery System for Synergistic Cancer Therapy
Authors: Yang Xinjian , Liu Zhen , Li Zhenhua , Pu Fang , Ren Jinsong , Qu Xiaogang 
Published: June 2013

AbstractHydrophobicity has been an obstacle that hinders the use of many anticancer drugs. A critical challenge for cancer therapy concerns the limited availability of effective biocompatible delivery systems for most hydrophobic therapeutic anticancer drugs. In this study, we have developed a targeted near‐infrared (NIR)‐regulated hydrophobic drug‐delivery platform based on gold nanorods incorporated within a mesoporous silica framework (AuMPs). Upon application of NIR light, the photothermal effect of the gold nanorods leads to a rapid rise in the local temperature, thus resulting in the release of the entrapped drug molecules. By integrating chemotherapy and photothermotherapy into one system, we have studied the therapeutic effects of camptothecin‐loaded AuMP‐polyethylene glycol‐folic acid nanocarrier. Results revealed a synergistic effect in vitro and in vivo, which would make it possible to enhance the therapeutic effect of hydrophobic drugs and decrease drug side effects. Studies have shown the feasibility of using this nanocarrier as a targeted and noninvasive remote‐controlled hydrophobic drug‐delivery system with high spatial/temperal resolution. Owing to these advantages, we envision that this NIR‐controlled, targeted drug‐delivery method would promote the development of high‐performance hydrophobic anticancer drug‐delivery system in future clinical applications.
Polynuclear Complexes with Alkoxo and Phenoxo Bridges from In Situ Generated Hydroxy‐Rich Schiff Base Ligands: Syntheses, Structures, and Magnetic Properties
Authors: Ding Caixia , Gao Chen , Ng Seikweng , Wang Bingwu , Xie Yongshu 
Published: June 2013

AbstractComplexes of new Schiff base ligands generated in situ from the reaction of 1‐aminoglycerol, aldehydes, and metal ions are reported. [Cu4(HL1)4] (1) and [Ni4O(HL1)3(H2O)3)]⋅6 H2O⋅DMF⋅DMSO (2) have M4O4 cubane cores, with the L/M molar ratios of 4:4 and 3:4, respectively. [MnIII3MnIINaOCl4(HL1)3]⋅3 MeCN (3) has a unique pentanuclear trigonal propeller‐shaped MnIII3MnIINa core structure, and the coordination assemblies are linked by hydrogen bonds to afford a 3D channel structure. [Cu2(HL2)2] (4) has a bis(μ2‐alkoxo)‐bridged Cu2O2 core, with the binuclear species linked by hydrogen bonds to afford a 1D double‐chain. [Ni7(OH)2(OCH3)4(H2L3)2(MeOH)2(H2O)2]‐ (ClO4)2⋅10 H2O (5) has a heptanuclear structure containing heptadentate di‐Schiff base ligands, with the nickel(II) ions bridged by phenoxo, alkoxo, hydroxo, and methoxo groups to afford a very rare face‐sharing hexadruple defective cubane core with a Ni@Ni6 arrangement. The lattice water molecules are linked by hydrogen bonds to form helical chains, which are further hydrogen‐bonded to the coordination moieties to afford a 2D network. Variable temperature magnetic susceptibility measurements and nonlinear data‐fitting revealed that the “2+4” type of cubane complex 1 shows medium intradimeric ferromagnetic interactions and weak interdimeric ferromagnetic interactions. For complexes 2 and 5, coexistent ferro‐ and antiferromagnetic couplings afford a non‐zero spin ground state. However, compound 3 shows antiferromagnetic interactions between MnIII and MnII, and ferromagnetic interactions between the MnIII centers, resulting in a global antiferromagnetic behavior. In conclusion, the reaction of 1‐aminoglycerol with aldehydes and metal salts afforded polynuclear complexes with a rich structural diversity and remarkable magnetic behavior.
Electrospun Spinel LiNi0.5Mn1.5O4 Hierarchical Nanofibers as 5 V Cathode Materials for Lithium‐Ion Batteries
Authors: Liu Jun , Liu Wei , Ji Shaomin , Zhou Yichun , Hodgson Peter , Li Yuncang 
Published: June 2013

AbstractSpinel LiNi0.5Mn1.5O4 hierarchical nanofibers with diameters of 200–500 nm and lengths of up to several tens of micrometers were synthesized using low‐cost starting materials by electrospinning combined with annealing. Well‐separated nanofiber precursors impede the growth and agglomeration of LiNi0.5Mn1.5O4 particles. The hierarchical nanofibers were constructed from attached LiNi0.5Mn1.5O4 nanooctahedrons with sizes ranging from 200 to 400 nm. It is proven that these LiNi0.5Mn1.5O4 hierarchical nanofibers exhibit a favorable electrochemical performance. At a 0.5 C (coulombic) rate, it shows an initial discharge capacity of 133 mA h g−1 with a capacity retention over 94 % after 30 cycles. Even at 2, 5, 10, and 15 C rates, it can still deliver a discharge capacity of 115, 100, 90, and 80 mA h g−1, respectively. Compared with self‐aggregated nanooctahedrons synthesized using common sol–gel methods, the LiNi0.5Mn1.5O4 hierarchical nanofibers exhibit a much higher capacity. This is owing to the fact that the self‐aggregation of the unique nanooctahedron‐in‐nanofiber structure has been greatly reduced because of the attachment of nanopolyhedrons in the long nanofibers. This unique microstructured cathode results in the large effective contact areas of the active materials, conductive additives and fully realize the advantage of nanomaterial‐based cathodes.
Microscale Gradients of Oxygen, Hydrogen Peroxide, and pH in Freshwater Cathodic Biofilms
Authors: Babauta Jerome T. , Nguyen Hung Duc , Istanbullu Ozlem , Beyenal Haluk 
Published: June 2013

AbstractCathodic reactions in biofilms employed in sediment microbial fuel cells is generally studied in the bulk phase. However, the cathodic biofilms affected by these reactions exist in microscale conditions in the biofilm and near the electrode surface that differ from the bulk phase. Understanding these microscale conditions and relating them to cathodic biofilm performance is critical for better‐performing cathodes. The goal of this research was to quantify the variation in oxygen, hydrogen peroxide, and the pH value near polarized surfaces in river water to simulate cathodic biofilms. We used laboratory river‐water biofilms and pure culture biofilms of Leptothrix discophora SP‐6 as two types of cathodic biofilms. Microelectrodes were used to quantify oxygen concentration, hydrogen peroxide concentration, and the pH value near the cathodes. We observed the correlation between cathodic current generation, oxygen consumption, and hydrogen peroxide accumulation. We found that the 2 e− pathway for oxygen reduction is the dominant pathway as opposed to the previously accepted 4 e− pathway quantified from bulk‐phase data. Biofouling of initially non‐polarized cathodes by oxygen scavengers reduced cathode performance. Continuously polarized cathodes could sustain a higher cathodic current longer despite contamination. The surface pH reached a value of 8.8 when a current of only −30 μA was passed through a polarized cathode, demonstrating that the pH value could also contribute to preventing biofouling. Over time, oxygen‐producing cathodic biofilms (Leptothrix discophora SP‐6) colonized on polarized cathodes, which decreased the overpotential for oxygen reduction and resulted in a large cathodic current attributed to manganese reduction. However, the cathodic current was not sustainable.
Reacquisition, reinstatement, and renewal of a conditioned taste aversion in preweanling rats
Authors: Revillo D. A. , Castello S. , Paglini G. , Arias C. 
Published: June 2013

ABSTRACTPavlovian extinction is defined as a reduction of the conditioned response (CR) as a consequence of repeated and nonreinforced presentations of the conditioned stimulus (CS). This phenomenon has been explained through two nonexclusive associative hypotheses. One of them proposes that the CS–unconditioned stimulus (US) association is weakened during extinction, while the second one explains extinction by the formation of a new inhibitory association between the CS, and the US (CS–noUS) which competes with the excitatory one acquired at conditioning (CS–US). Research supporting this second hypothesis is based on the demonstration that the CR can be recovered after extinction. However, in preweanling rats, renewal, and reinstatement treatments have failed to recover a conditioned fear response, suggesting that extinction during this ontogenetic period may involve erasure of the CS–US association. The goal of the present study was to explore whether this conclusion can be extended to the extinction of a conditioned taste aversion by evaluating infant rats in three different procedures (reacquisition, ABA renewal, and reinstatement). The results are consistent with the idea that extinction of a taste aversive memory during infancy involves relearning about the relationship between the CS and the US, with the initial CS–US association remaining relatively intact. Extinction of a taste aversive memory and a fear memory may involve different biological mechanisms during infancy. The conclusion that the only psychological mechanism for extinction during infancy is unlearning should be confined to a particular type of memory. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 56: 713–725, 2014.