bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Support, Particle Size, and Process Parameters on Co3O4 Catalyzed H2O Oxidation Mediated by the [Ru(bpy)3]2+ Persulfate System
Authors: Yang Chieh‐Chao , Eggenhuisen Tamara M. , Wolters Mariska , Agiral Anil , Frei Heinz , de Jongh Petra E. , de Jong Krijn P. , Mul Guido 
Published: January 2013

AbstractWater oxidation over highly dispersed cobalt oxide particles in porous silica was studied, applying photo‐activation of the Ru(bpy)32+ photosensitizer complex and the sacrificial electron acceptor (S2O82−). Under identical process conditions, 4 nm crystalline Co3O4 particles dispersed in SBA‐15, obtained by calcination of impregnated Co(NO3)2 in an NO/N2 atmosphere, showed higher O2 evolution rates than 7 nm Co3O4 particles, obtained by air calcination of the same catalyst precursor. A similar trend was observed for Co3O4 dispersed in MCM‐41, although MCM‐41 catalysts showed lower O2 production rates than SBA‐15 catalysts of comparable Co3O4 sizes. The positive effect of a small Co3O4‐particle size is related to the higher amount of surface sites of Co3O4 interacting with the Ru complex, which subsequently leads to water oxidation. The effect of the silica scaffold was demonstrated to be the result of the higher surface area of MCM‐41 versus SBA‐15 (≈1000 m2 g−1 versus 600 m2 g−1). Consequently a larger fraction of the [Ru(bpy)3]2+ photosensitizer complex immobilizes on the silica walls, and thus becomes ineffective to stimulate water oxidation. The nanosized Co3O4 particles in general were more effective than previously reported micron‐sized crystals, even though nanostructuring leads to less favorable optical properties of Co3O4. The stability of the used Ru(bpy)32+ sensitizer, which is a function of mode of irradiation (wavelength) and buffer capacity, was found to be a major factor in controlling the evolved oxygen quantity.
Remarkable Reinforcement of a Supramolecular Gel Constructed by Heteroditopic [18]Crown‐6‐Based Molecular Recognition
Authors: Noh Eunyoung , Park Sunhong , Kang Sunwoo , Lee Jin Yong , Jung Jong Hwa 
Published: January 2013

AbstractThe heteroditopic crown ether‐based ligand 1 containing the diazafluorenylimino group as a binding site for the Zn2+ and Cs+ was synthesized. The ligand 1 can be gelated in DMSO/water with and without Cs+ in the presence of the Zn2+ ion. Interestingly, the remarkable gelation reinforcement of gel 1 occurred with Cs+ in the presence of Zn2+, which is due to the formation of a sandwich complex. According to DFT calculations, one Zn2+ is bound to two diazafluorenylimino moieties in a tetrahedral structure. In addition, one Cs+ ion is bound to two crown‐rings. The Zn2+‐diazafluorenylimino ligand gel without Cs+ shows a spherical structure with 250–800 nm diameter, whereas the Zn2+‐diazafluorenylimino‐based ligand gel with Cs+ shows a fiber structure with 60–70 nm diameter and several micrometers of lengths. The rheological properties of the Zn2+‐ diazafluorenylimino‐based ligand gel were strongly dependent on the presence of Cs+.
Luminescent Coordination Polymers Based on Self‐Assembled Cadmium Dipyrrin Complexes
Authors: Béziau Antoine , Baudron Stéphane A. , Guenet Aurélie , Hosseini Mir Wais 
Published: January 2013

AbstractA series of novel CdII complexes based on α,β‐unsubstituted dipyrrin ligands (dpm) has been prepared and characterised both in solution and in the solid state. These compounds are of the [Cd(dpm)2] type, with the coordination sphere of the metal centre occupied by two dpm chelates. Interestingly, in contrast to what has been reported for the ZnII analogues, in the presence of a pyridyl‐ or imidazolyl‐appended dpm ligand, the coordination number of the CdII cation can be increased to six, leading to an octahedral coordination sphere. As a consequence, the formation of 1‐, 2‐, and 3D coordination polymers by self‐assembly is observed. Photophysical investigations of the discrete complexes and self‐assembled networks have demonstrated that both types of compounds are luminescent in the solid state.
Polysulfide Chemistry in Sodium–Sulfur Batteries and Related Systems— A Computational Study by G3X(MP2) and PCM Calculations
Authors: Steudel Ralf , Steudel Yana 
Published: January 2013

AbstractThe sodium–sulfur (NAS) battery is a candidate for energy storage and load leveling in power systems, by using the reversible reduction of elemental sulfur by sodium metal to give a liquid mixture of polysulfides (Na2Sn) at approximately 320 °C. We investigated a large number of reactions possibly occurring in such sodium polysulfide melts by using density functional calculations at the G3X(MP2)/B3LYP/6‐31+G(2df,p) level of theory including polarizable continuum model (PCM) corrections for two polarizable phases, to obtain geometric and, for the first time, thermodynamic data for the liquid sodium–sulfur system. Novel reaction sequences for the electrochemical reduction of elemental sulfur are proposed on the basis of their Gibbs reaction energies. We suggest that the primary reduction product of S8 is the radical anion ${{\rm S}{{{{\bullet}}- \hfill \atop 8\hfill}}}$, which decomposes at the operating temperature of NAS batteries exergonically to the radicals ${{\rm S}{{{{\bullet}}- \hfill \atop 2\hfill}}}$ and ${{\rm S}{{{{\bullet}}- \hfill \atop 3\hfill}}}$ together with the neutral species S6 and S5, respectively. In addition, ${{\rm S}{{{{\bullet}}- \hfill \atop 8\hfill}}}$ is predicted to disproportionate exergonically to S8 and ${{\rm S}{{2- \hfill \atop 8\hfill}}}$ followed by the dissociation of the latter into two ${{\rm S}{{{{\bullet}}- \hfill \atop 4\hfill}}}$ radical ions. By recombination reactions of these radicals various polysulfide dianions can in principle be formed. However, polysulfide dianions larger than ${{\rm S}{{2- \hfill \atop 4\hfill}}}$ are thermally unstable at 320 °C and smaller dianions as well as radical monoanions dominate in Na2Sn (n=2–5) melts instead. The reverse reactions are predicted to take place when the NAS battery is charged. We show that ion pairs of the types ${{\rm NaS}{{{{\bullet}}\hfill \atop 2\hfill}}}$, ${{\rm NaS}{{- \hfill \atop n\hfill}}}$, and Na2Sn can be expected at least for n=2 and 3 in NAS batteries, but are unlikely in aqueous sodium polysulfide except at high concentrations. The structures of such radicals and anions with up to nine sulfur atoms are reported, because they are predicted to play a key role in the electrochemical reduction process. A large number of isomerization, disproportionation, and sulfurization reactions of polysulfide mono‐ and dianions have been investigated in the gas phase and in a polarizable continuum, and numerous reaction enthalpies as well as Gibbs energies are reported.
A Dual‐Functional Metallogel of Amphiphilic Copper(II) Quinolinol: Redox Responsiveness and Enantioselectivity
Authors: Miao Wangen , Zhang Li , Wang Xiufeng , Cao Hai , Jin Qingxian , Liu Minghua 
Published: January 2013

AbstractA dual‐functional metallogel, which was based on the copper(II) complex of quinolinol‐substituted L‐glutamide, showed both redox‐responsive and enantioselective properties; moreover, the metallogels collapsed into a sol after reduction and could be revived upon subsequent oxidation. The supramolecular chirality and morphology also reversible changed with the gel–sol transition. Furthermore, the metallogels showed new enantioselective recognition towards chiral aromatic amino acids. A new emission band in the blue‐light region at around 393 nm appeared when the metallogels encountered L‐aromatic amino acids, whereas no new emission band was observed for the corresponding D‐aromatic amino acids. Such enantioselectivity only occurred in the gel state. No similar phenomenon could be observed in solution. This result suggested that, during the gel formation, the gelator molecules self‐assembled into ordered, chiral supramolecular structures and enhanced the enantiorecognition of the L‐aromatic amino acids.
Photophysical Properties and Conformational Effects on the Circular Dichroism of an Azobenzene–Cyclodextrin [1]Rotaxane and Its Molecular Components
Authors: Di Motta Simone , Avellini Tommaso , Silvi Serena , Venturi Margherita , Ma Xiang , Tian He , Credi Alberto , Negri Fabrizia 
Published: January 2013

AbstractThe photophysical properties of a multicomponent [1]rotaxane bearing a β‐cyclodextrin ring covalently connected to an axle comprising an azobenzene photoisomerisable moiety and a naphthalimide‐type fluorescent stopper are investigated by a combined experimental and computational study. The absorption and fluorescence spectra, and particularly the induced circular dichroism (ICD) signal, are determined. The latter shows a sign relation that cannot be rationalised in terms of the simple general rules commonly employed to analyse the ICD spectra of achiral guests encircled by chiral hosts. To assist the interpretation of experimental results, DFT and time‐dependent (TD) DFT calculations are performed to explore the availability of low‐energy conformations and to model their spectroscopic response. Molecular dynamics simulations performed in water show the interconversion of a number of conformers, the contribution of which to the ICD signal is in agreement with the observation.
Underpotential Deposition‐Induced Synthesis of Composition‐Tunable PtCu Nanocrystals and Their Catalytic Properties
Authors: Jiang Yaqi , Jia Yanyan , Zhang Jiawei , Zhang Lei , Huang Huang , Xie Zhaoxiong , Zheng Lansun 
Published: January 2013

AbstractPtCu alloy octahedral nanocrystals (NCs) have been synthesized successfully by using N,N‐dimethylformamide as both the solvent and the reducing agent in the presence of cetyltrimethylammonium chloride. Cu underpotential deposition (UPD) is found to play a key role in the formation of the PtCu alloy NCs. The composition in the PtCu alloy can be tuned by adjusting the ratio of metal precursors in solution. However, the Cu content in the PtCu alloy NCs cannot exceed 50 %. Due to the fact that Cu precursor cannot be reduced to metallic copper and the Cu content cannot exceed 50 %, we achieved the formation of the PtCu alloy by using Cu UPD on the Pt surface. In addition, the catalytic activities of PtCu alloy NCs with different composition were investigated in electrocatalytic oxidation of formic acid. The results reveal that the catalytic performance is strongly dependent on PtCu alloy composition. The sample of Pt50Cu50 exhibits excellent activity in electrocatalytic oxidation of formic acid.
Synthesis and Biological Evaluation of the Forssman Antigen Pentasaccharide and Derivatives by a One‐Pot Glycosylation Procedure
Authors: Tanaka Hiroshi , Takeuchi Ryota , Jimbo Mitsuru , Kuniya Nami , Takahashi Takashi 
Published: January 2013

AbstractThe synthesis and biological evaluation of the Forssman antigen pentasaccharide and derivatives thereof by using a one‐pot glycosylation and polymer‐assisted deprotection is described. The Forssman antigen pentasaccharide, composed of GalNAcα(1,3)GalNAcβ(1,3)Galα(1,4)Galβ(1,4)Glc, was recently identified as a ligand of the lectin SLL‐2 isolated from an octocoral Sinularia lochmodes. The chemo‐ and α‐selective glycosylation of a thiogalactoside with a hemiacetal donor by using a mixture of Tf2O, TTBP and Ph2SO, followed by activation of the remaining thioglycoside, provided the trisaccharide at the reducing end in a one‐pot procedure. The pentasaccharide was prepared by the α‐selective glycosylation of the N‐Troc‐protected (Troc=2,2,2‐trichloroethoxycarbonyl) thioglycoside with a 2‐azide‐1‐hydroxyl glycosyl donor, followed by glycosidation of the resulting disaccharide at the C3 hydroxyl group of the trisaccharide acceptor in a one‐pot process. We next applied the one‐pot glycosylation method to the synthesis of pentasaccharides in which the galactosamine units were partially and fully replaced by galactose units. Among the three possible pentasaccharides, Galα(1,3)GalNAc and Galα(1,3)Gal derivatives were successfully prepared by the established method. An assay of the binding of the synthetic oligosaccharides to a fluorescent‐labeled SLL‐2 revealed that the NHAc substituents and the length of the oligosaccharide chain were both important for the binding of the oligosaccharide to SLL‐2. The inhibition effect of the oligosaccharide relative to the morphological changes of Symbiodinium by SLL‐2, was comparable to their binding affinity to SLL‐2. In addition, we fortuitously found that the synthetic Forssman antigen pentasaccharide directly promotes a morphological change in Symbiodinium. These results strongly indicate that the Forssman antigen also functions as a chemical mediator of Symbiodinium.
Five‐Year Soil Respiration Reflected Soil Quality Evolution in Different Forest and Grassland Vegetation Types in the Eastern Loess Plateau of China
Authors: Yan Junxia , Chen Liangfu , Li JunJian , Li Hongjian 
Published: January 2013

AbstractSoil CO2 efflux in forest and grassland over 5 years from 2005 to 2009 in a semiarid mountain area of the Loess plateau, China, was measured. The aim was to compare the soil respiration and its annual and inter‐annual responses to the changes in soil temperature and soil water content between the two vegetation types for observing soil quality evolution. The differences among the five study years were the annual precipitation (320.1, 370.5, 508.8, 341.6, and 567.4 mm in 2005–2009, respectively) and annual distribution. The results showed that the seasonal change of soil respiration in both vegetation types was similar and controlled by soil temperature and soil water content. The mean soil respiration across 5 years in the forest (3.78 ± 2.68 µmol CO2 m−2 s−1) was less than that in the grassland (4.04 ± 3.06 µmol CO2 m−2 s−1), and the difference was significant. The drought soil in summer depressed soil respiration substantially. The Q10 value across 5‐year measurements was 2.89 and 2.94 for forest and grassland. When soil water content was between wilting point (WP) and field capacity (FC), the Q10 in both types increased with increasing soil water content, and when soil water content dropped to below WP, soil respiration and the Q10 decreased substantially. Although an exponential model was well fitted to predict the annual mean soil respiration for each single year data, it overestimated and underestimated soil respiration, respectively, in drought conditions and after rain for short periods of time during the year. The two‐variable models including temperature and water content variables could be well used to predict soil respiration for both types in all weather conditions. The models proposed are useful for understanding and predicting potential changes in the eastern part of Loess plateau in response to climate change.
Tissue flow cytometry immunophenotyping in the diagnosis and classification of non‐Hodgkin's lymphomas: A retrospective evaluation of 1,792 cases
Authors: Demurtas Anna , Stacchini Alessandra , Aliberti Sabrina , Chiusa Luigi , Chiarle Roberto , Novero Domenico 
Published: January 2013

AbstractA retrospective analysis of 1,792 solid tissues suggestive of lymphoma, submitted over a 12‐year period, was carried out and flow cytometry (FC) results were compared with histologic findings. The final histologic diagnosis of cases documented in this report is as follows: 1,270 non‐Hodgkin's lymphomas (NHL); 17 composite lymphomas; four NHL plus carcinomas; five post‐transplant lymphoproliferative disorders; 105 Hodgkin's lymphomas (HL); eight acute leukemias; 42 tissue cancers; and 341 non‐neoplastic diseases. A strong correlation between morphology and FC data was observed among hematological malignancies (1,268/1,304, 97.2%) with the exception of HL. Among B‐NHL, FC detection of clonally restricted B‐cell allowed the identification of lymphomas that were not histologically clear and the differential diagnosis between follicular lymphoma and reactive hyperplasia. A high correlation level (r = 0.83; P < 0.0001) was obtained in comparing proliferation results obtained by FC and immunohistochemistry. Among T‐NHL, FC detection of an aberrant phenotype direct histologic diagnosis in cases having less than 20% of neoplastic cells. In nine cases, FC suggested the need to evaluate a neoplastic population, not morphologically evident. Results show that FC routinely performed on tissue samples suspected of lymphomas is a fundamental adjunct to morphology in the diagnosis of NHL and may enhance the performance of the histologic evaluation so as to achieve the final diagnosis. To the best of our knowledge, this is the first report in the literature of a wide series of tissues also studied by FC. © 2013 International Clinical Cytometry Society
Development of a C‐Terminal Site‐Specific PEGylated Analog of GLP‐1 with Improved Anti‐Diabetic Effects in Diabetic Mice
Authors: Gao Mingming , Tong Yue , Gao Xiangdong , Yao Wenbing 
Published: January 2013

Abstract

Preclinical Research

Glucagon‐like peptide‐1 (GLP‐1) is an attractive lead for antidiabetic drug development but its utility is limited due to poor in vivo stability. In this study, we developed a C‐terminal site‐specific PEGylated analog of GLP‐1 based on the structure‐activity relationship of GLP‐1. Using three steps of chromatography, we obtained the conjugate with a high purity. Polyethylene glycol (PEG) conjugation greatly enhanced GLP‐1 potency in vivo without changing its original conformation. In streptozotosin diabetic mice, this conjugate had an improved antidiabetic effect, as measured by fasting glucose/insulin/glycosylated serum protein, oral glucose tolerance test, and histochemical studies. Additionally, this PEG‐conjugated peptide delayed gastric emptying without significant effects on body weight gain. Our data indicate that this conjugate may be a promising lead for the development of antidiabetic drugs.
Antiarrhythmic Efficacy of CPUY11018 Under Pathological Conditions
Authors: Xu Jing , Yu Peng , Yang Qian , Meng Jia‐ning , Shan Jiao‐jiao , You Qi‐dong , Tang Yi‐qun 
Published: January 2013

Abstract

Preclinical Research

In the present study, we investigated the antiarrhythmic potential of the multichannel blocker CPUY11018 (CY18) in rat cardiac hypertrophy, induced using 7‐day treatment with isoproterenol (ISO) (2.5 mg/kg day, s.c.). Arrhythmias were produced using a coronary ligation‐reperfusion procedure. CY18 (3 and 10 mg/kg per day, i.p.) and valsartan (10 mg/kg per day, p.o.) were administrated on days 4–7 of ISO treatment. Heart weight index, hemodynamic parameters, electrocardiogram (ECG II) parameters, and arrhythmic scores were monitored and recorded. We examined the ability of CY18 to block the IKr channel under conditions of acidosis and excess reactive oxygen species production in CHO cells expressing the hERG. CY18 had strong antiarrhythmic effects, potentially due to multichannel inhibition. The protective role of CY18 against ISO‐induced myocardial hypertrophy was further confirmed using ECG. Incidences of ventricular tachycardia and ventricular fibrillation, heart weight/body weight ratios, and arrhythmic scores were higher in the model group and were suppressed with CY18 treatment. Under simulated pathological conditions, the inhibitory effect of CY18 was impaired in cells treated with 30 μM H2O2, which was more effective than acidosis in attenuating CY18‐induced inhibition of hERG channel activity.
Palladium‐Catalyzed ortho‐Aroylation of 2‐Arylbenzothiazoles and 2‐Arylbenzoxazoles with Aldehydes
Authors: Banerjee Arghya , Santra Sourav Kumar , Guin Srimanta , Rout Saroj Kumar , Patel Bhisma K. 
Published: January 2013

AbstractAn efficient protocol for the ortho‐aroylation of 2‐arylbenzothiazoles and 2‐arylbenzoxazoles has been developed using aldehydes as the aroyl source. This Pd‐catalyzed substrate‐directed sp2‐hybridized C–H bond functionalization occurs in the presence of the oxidant tert‐butyl hydroperoxide. A variety of functional groups on the 2‐arylbenzothiazoles, 2‐arylbenzoxazoles, and aldehydes are tolerated under the reaction conditions. Regioselective aroylation at the less hindered ortho position was observed for meta‐substituted 2‐arylbenzothiazoles.
Comparative Study of Lead(II) Selective Poly(vinyl chloride) Membrane Electrodes Based on Podand Derivatives as Ionophores
Authors: Singh Sanjay , Rani Geeta , Singh Gyanendra , Agarwal Himanshu 
Published: January 2013

AbstractThe two podand chelates based on diethylsulfide, 1,5‐bis(2′‐hydroxy‐4′‐nitrophenoxy)‐3‐thiapentane (L1) and 1,5‐bis(8′‐oxybenzopyridine)‐3‐thia pentane (L2), have been synthesized and explored as neutral ionophores for preparing poly(vinyl chloride) based membrane electrodes selective to Pb2+. The addition of anionic additives and various plasticizers has been found to substantially improve the performance of the electrode. The best performance was obtained with the electrode No. 1 having a membrane of ionophore (L1) with the composition PVC:o‐NPOE:ionophore (L1):NaTFPB (%w/w) of 33 : 62 : 3 : 2. The electrode exhibits Nernstian response with a slope of 31.57±0.3 mV decade−1 of activity in the concentration range from 2.0×10−9 to 1.0×10−1 M Pb2+, performs satisfactorily over a wide pH range (1.6–7.0), with a fast response time (5 s).
Time‐variant sustainability assessment of seismically vulnerable bridges subjected to multiple hazards
Authors: Dong You , Frangopol Dan M. , Saydam Duygu 
Published: January 2013

SUMMARYIn the design and assessment of structures, the aspects regarding the future performance are gaining increased attention. A wide range of performance measures is covered by ‘sustainability’ to reflect these aspects. There is the need for well established methods for quantifying the metrics of sustainability. In this paper, a framework for assessing the time‐variant sustainability of bridges associated with multiple hazards considering the effects of structural deterioration is presented. The approach accounts for the effects of flood‐induced scour on seismic fragility. Sustainability is quantified in terms of its social, environmental, and economic metrics. These include the expected downtime and number of fatalities, expected energy waste and carbon dioxide emissions, and the expected loss. The proposed approach is illustrated on a reinforced concrete bridge. The effects of corrosion on reinforcement bars and concrete cover spalling are accounted. The seismic fragility curves at different points in time are obtained through nonlinear finite element analyses. The variation of the metrics of sustainability in time is presented. The effects of flood‐induced scour on both seismic fragility and metrics are also investigated. Copyright © 2013 John Wiley & Sons, Ltd.