bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intramolecular reaction and intramolecular catalysisd̊ II. Mechanism of intramolecular catalysis in hydrolysis of 2‐(2'‐benzimidazolyl)phenyl acetate by benzimidazolyl group
Authors: Xia Chi‐Zhong , Xia Dao‐Hong 
Published: September 2010

AbstractAs a model for acetyl‐α‐chymotrypsin, 2‐(2'‐benzimidazolyl)phenyl acetate was synthesized in a good yield and its hydrolytic kinetics has been studied in buffer solutions at 45'C within a wide pH range (0.65–8.80). The measured pseudo‐first‐order rate constants (kobs) at different pH values conform well with the data derived from the proposed theoretical model. It is shown that in an acidic solution of medium strength (pH = 2.0–3.0), the ester is hydrolyzed via intramolecular general acid catalysis by benzimidazolium cation; while at pH values near neutrality (pH = 5.5–7.0), this ester is hydrolyzed via intramolecular general base catalysis by neutral benzimidazole. These findings are discussed and the activation parameters of the hydrolysis reaction were also determined.
Lower photoreactivity of 3‐methyl‐3‐(4′‐biphenylyl)‐t‐butene
Authors: Wu Guo‐Sheng , Hu Jun , Li Jiang‐Pin , Xu Jian‐Hua 
Published: September 2010

AbstractDirect and sensitized photolyses of 3‐methyl‐3‐(4′‐biphenylyl)‐1‐butene gave 1,1‐dimethyl‐2‐(4′‐biphenylyl)cyclopropane as primary product and 2‐methyl‐4‐(4′‐biphenylyl)‐1‐butene as secondary product with quantum yields of 7.6×10−3 and 5.6×10−3, respectively. On direct photolysis, the triplet reactant rearranged with a quantum yield of 4.4×10−3 and is more reactive than the singlet. The exceptionally low photoreactivity shows that the excitation energy is largely localized on the biphenylyl portion but can be delivered to the reaction center slowly.
New metabolites from the fungus Stereum purpureum
Authors: Xie Jin‐Lun , Li Li‐Ping 
Published: September 2010

AbstractTwo new sterpurene sesquiterpenes, 4,12‐dihydroxysterpurene (1) and 5,12‐dihydroxysterpurene (3), have been isolated from Stereum purpureum, and identified mainly on the basis of mass spectra and extensive nuclear magnetic resonance spectrometry, especially two‐dimensional NMR.
Zinc‐containing chainlike polymer {Cs2[Zn(S2C=C(CN)2)2]}n, the second example of bridging [S2C=C(CN)2]
Authors: Zhu Yong‐Bao , Lu Shao‐Fang , Huang Xiao‐Ying , Wu Qiang‐Jin , Zhang Yu‐Dong 
Published: September 2010

AbstractThe title compound {Cs2[Zn(S2C=C(CN)2)2]}n(2), Catena‐poly {dicesium [bis(1.1‐dicyanoethene‐2,2‐dithiolato‐S,S':N)‐Zinc(II)]}, is the second example of bridging [S2C=C(CN)2] (hereafter referred to as i‐mnt) for metal‐containing polymer. It crystallizes in the non‐centrosymmetric space group Ia (alt. Cc, No.9) There are two coordination modes of i‐mnt in this compound: μ‐ηl‐ηl‐i‐mnt, bridging two Zn moieties with two S atoms and terminal i‐mnt. A characteristic feature of the structure is the infinite ‐Zn(η2‐i‐mnt)(η1‐η1‐i‐mnt)‐Zn(η1‐η1‐i‐mnt)(η2‐i‐mnt)‐wav∼Like chain. Cs atoms are located between the chains to form three‐dimensional network‐like packing. An efficient second harmonic generation &om the crystal has been observed on the irradiation with the 1064 nm output of a Nd:YAG laser.
A Novel Method for Fixed‐node Quantum Monte Carlo
Authors: Huang Hong‐Xin , Zhao Zhen‐Hua 
Published: September 2010

AbstractIn this paper, a novel method for fixed‐node quantum Monte Carlo is given. By comparing this method with the traditional fixed‐node one, this novel method can be applied to calculate molecular energy more exactly. An expansion of the eigenvalue of the energy for a system has been derived. It is proved that the value of the energy calculated using the traditional fixed‐node method is only the zeroth order approximation of the eigenvalue of the energy. But when using this novel method, in the case of only increasing less computing amounts ( < 1%), the first order approximation, the second order approximation, and so on can be obtained conveniently with the detailed equations and steps in the practical calculation to calculate the values of the zeroth, first and second approximation of the energies of 1 1A, state of CH2, 1A2(C4h, acet) state of C8 and the ground‐states of H2, LiH, Li2, and H2O The results indicate that for these states it needs only the second order approximation to obtain over 97% of electronic correlation energy, which demonstrates that this novel method is very excellent in both the computing accuracy and the amount of calculation required.
Ab initio Study on the Intermolecular Interaction and Thermodynamic Properties of Methyl Nitrate Dimer
Authors: Tan Jin‐Zhi , Xiao He‐Ming , Gong Xue‐Dong , Li Jin‐Shan 
Published: September 2010

AbstractThree stable dimers of methyl nitrate have been obtained and their geometries have been fully optimized at the HF/6‐31G,. level. Binding energies have been calculated with correction for the basis set superposition error (BSSE) and zero point energy (ZPE). The cyclic overlap‐type structure, the binding energy of which is 11.97 kJ/mol at the MP4SDTQ/6‐31G. / HF/6‐31G. level, is the most stable. No intermolecular hydrogen bond was found, and the charge transfer between two subsystems is minute. The thermodynamic properties of methyl nitrate and its dimers have been calculated based on the vibrational analysis and statistical thermodynamics.
Density Functional Studies of the CF Bond Activation of CF3 Radical by Bare Co+
Authors: Zhang Dong‐Ju , Liu Cheng‐Bu , Hu Hai‐Quan , Liu Yong‐Jun 
Published: September 2010

AbstractThe CF bond activation mechanism of CF3 radical by bare Co+ has been studied by density functional theory. Three local minima and two first‐order saddle points were located for the potential energy surface (PES) of [Co, C, F3]+. The activation barrier involving CF bond activation was calculated to be only 14.73 kJ/mol, while the largest barrier of 149.29 kJ/mol on the FES involves CoC bond rupture. The bonding mechanism between Co+, C and F atoms were discussed based on Mulliken population. The relevant bond dissociation energy and thermochemistry data were calculated with the limited experimental values, and the results are in good agreement with the experimental findings.
Fluorescence Spectral Studies on the Coordination of Calix[4]‐arenes Bearing Boronic Acid Moieties with Monosaccharides
Authors: Lu Kui , Wu Yang‐Jie , Li Yong‐Hong , Shi Ya‐Lin , Zhou Zhi‐Xian 
Published: September 2010

AbstractCoordination of ten calix[4]arenes bearing boronic acid moieties with five monosaccharides was studied by fluorescence spectrometry. The stability constants (K2) of the complexes and Gibbs free energy change ( ‐ ΔG0) of the coordination reactions were calculated according to the modified Hilderbrand‐Benesi equation. The results obtained indicated that the coordination ability of D‐( ‐ )‐fructose with calix[4] arenes bearing boronic acid moieties was stronger than that of the other monosaccharides. And these calix[4]arene derivatives might be used for identification of L‐( ‐ )‐sorbose.
Structural Transformation of the Peptide Fragments from the Reactive Center Loops of Serpins: Circular Dichroic Studies
Authors: Hu Hong‐Yu , Chen Yun‐Neng , Xu Song‐Qin , Xu Gen‐Jun 
Published: September 2010

AbstractTwo peptides, derived from the reactive center of ovalbumin (OVARC) and plasminogen activator inhibitor‐1 (PAIRC) respectively were chemically synthesized and investigated by circular dichroic spectroscopy. The secondary structural transformation in solution and in solid state was studied. OVARC shows a nascent helical structure in aqueous solution, and its helical content increases under acidic conditions. There is no obvious structural conversion from solution to solid state. PAIRC, however, undergoes a structural transformation from random coil in aqueous solution to a typical β‐sheet structure in the solid state. Hexafluoroisopropanol (HFIP) prompts helical structures of the two peptides in solution, but it seems to trigger the structural formation of β‐sheets in solid state. The novel structural transformation from random coil or nascent helical structure in aqueous solution to the α‐helix in HFIP and to the β‐sheet structure in solid state may reflect the conformational polymorphism of the serpin reactive centers and is implicated in the structural features of the amyloid aggregates.
MCM‐41 Supported Aminopropylsiloxane Palladium Acetate Complex: A Highly Active and Stereoselective Catalyst for Heck Reaction
Authors: Zhou Jian‐Min , Zhou Ren‐Xian , Mo Liu‐Ye , Zhao Shao‐Fen , Zheng Xiao‐Ming 
Published: September 2010

AbstractA new MCM‐41 supported aminopropylsiloxane palladium acetate was prepared and characterized. This catalyst is highly active and stereoselective for Heck reaction at 70°C.
Low‐valent Titanium Induced Reductive Coupling of O‐Nitrophenylazide with Benzoyl Substituted Ketene Dithioacetals: a Novel Synthesis of 4‐Aryl‐2‐methylthio‐3Z7‐l,5‐benzodiazepines
Authors: Li Zhi‐Fang , Zhang Yong‐Min 
Published: September 2010

AbstractTreated with the low‐valent titanium derived from TiCl4/Sm system, o‐nitrophenylazide could produce the intermediate 2 in situ, which reacted with benzoyl substituted ketene dithioacetals to afford 4‐aryl‐2‐methylthio‐3H‐1,5‐benzodiazepines in good yields under mild and neutral conditions.
Synthesis, Characterization and Molecular Structure of Ternary Cu(II) Complex with 1, 4, 8, 9‐Tetraazatriphenylene and L‐Phenylaninate
Authors: Le Xue‐Yi , Yang Guang , Feng Xiao‐Long , Ji Liang‐Nian 
Published: September 2010

AbstractThe complex [Cu(L‐Phe)(TATP)(H2O)]ClO4.0.5H2O has been synthesized and investigated by elemental analysis, molar conductivity, spectroscopic and X‐ray diffraction methods, where TATP= 1,4,8,9‐tetraazatriphenylene and L‐phe = L‐phenylaninate group. The complex crystallizes in the triclinic space group PI with two molecules in a unit cell of dimensions a=0.5730(l), b = 1.0190(2), c = 2.1430(4), α= 97.50 (1)°, β = 95.33(3)°, γ= 102.85(1)°, V= 1.1998(4) nm3, R1 = 0.0360, wR2 = 0.0400. The crystal contains two independent [Cu(L‐Phe) (TATP)(H2O)]+ complexes Cu1 and Cu2, having essentially the same distorted square‐pyramidal structure, where each Cu(II) ion coordinates two nitrogen atoms of TATP and the amino nitrogen and carboxylate oxygen atoms of L‐Phe in the equatorial positions and one water oxygen at an axial position.
Interconnection of heterogeneous knowledge bases and its application on Knowledge Grid
Authors: Nakanishi T. , Zettsu K. , Kidawara Y. , Kiyoki Y. 
Published: September 2010

AbstractRecently, the number of users who use search engines for not only retrieving Web pages but also understanding or learning an arbitrary concept has been increasing. However, it is difficult to understand and learn an arbitrary concept by using the existing search engines. This paper presents a method for the interconnection of heterogeneous knowledge bases on Knowledge Grid for knowledge sharing and provision. In this paper, for realizing the proposed method, we introduce two types of services—intra‐operation services and inter‐operation services—on Knowledge Grid. The system dynamically creates a semantic associative network that connects the user's interests and concepts, and provides correlation views that represent various relationships for connecting related resources. In addition, we employ a link‐free browsing system by this method called correlation browsing, which represents the semantic association utilizing collective knowledge by connecting various knowledge bases. The current web browsing has two actions—browsing and jumping by static hyperlinks. It is difficult to understand the relationship between each page that is connected by static hyperlink. The system navigates the related contents while repeatedly switching between a content browsing mode and a correlation browsing mode. Therefore, a user can access various contents while understanding the relationships. Copyright © 2010 John Wiley & Sons, Ltd.
A new approach for sparse matrix vector product on NVIDIA GPUs
Authors: Vázquez F. , Fernández J. J. , Garzón E. M. 
Published: September 2010

AbstractThe sparse matrix vector product (SpMV) is a key operation in engineering and scientific computing and, hence, it has been subjected to intense research for a long time. The irregular computations involved in SpMV make its optimization challenging. Therefore, enormous effort has been devoted to devise data formats to store the sparse matrix with the ultimate aim of maximizing the performance. Graphics Processing Units (GPUs) have recently emerged as platforms that yield outstanding acceleration factors. SpMV implementations for NVIDIA GPUs have already appeared on the scene. This work proposes and evaluates a new implementation of SpMV for NVIDIA GPUs based on a new format, ELLPACK‐R, that allows storage of the sparse matrix in a regular manner. A comparative evaluation against a variety of storage formats previously proposed has been carried out based on a representative set of test matrices. The results show that, although the performance strongly depends on the specific pattern of the matrix, the implementation based on ELLPACK‐R achieves higher overall performance. Moreover, a comparison with standard state‐of‐the‐art superscalar processors reveals that significant speedup factors are achieved with GPUs. Copyright © 2010 John Wiley & Sons, Ltd.
Performance evaluation of throughput in optical burst switching
Authors: Alam M. S. , Alsharif S. , Panati P. 
Published: September 2010

AbstractOptical burst switching (OBS) provides a promising solution to utilize the huge terahertz bandwidth of optical wavelength division multiplexing (WDM) transmission technology. To exploit this bandwidth, several reservation schemes have been proposed that include just‐in‐time (JIT) signaling, just‐enough‐time (JET) signaling and burst segmentation (BS). It is necessary to investigate the performance of these schemes under the same constraints for a prescribed OBS application. Accordingly, in this paper, we analyzed and compared the performance of JIT, JET and BS techniques under various scenarios such as network size, delay variation and load variation in an OBS network using various performance metrics, such as the offset time and switch configuration time. Also, the performance of the network under various switching delays was also investigated. The modified BS reservation scheme has been found to yield significantly better performance and better throughput compared with the JIT and JET reservation schemes. Test results show that the effect of varying loads as well as delays significantly impacts the performance of the OBS network. The results presented in this paper are expected to lead further performance improvements in OBS networks using the BS reservation scheme. Copyright © 2010 John Wiley & Sons, Ltd.
Oxidative stress after kidney transplantation: The role of immunosuppression
Authors: Štrebl Pavel , Horčička Jr. Vladko , Krejči Karel , Horák Pavel , Vostálová Jitka , Zdařilová Adéla , Kajabová Markéta , Schneiderka Petr , Zadražil Josef 
Published: September 2010

AbstractBACKGROUNDOxidative stress (OS) is one of the consequences of kidney transplantation (KT). The level of OS can be monitored using the total antioxidative status (TAS) and parameters that result from damaged molecules, such as advanced oxidation protein products (AOPPs). The aim of this study was to monitor OS in patients before and after KT, and to evaluate the effect of immunosuppressive therapy on the level and development of OS.METHODSParticipants in this prospective study were patients who underwent KT (n = 31; age 53.7% % 11.2 years; 20 males, 11 females). Patients were treated with immunosuppressives, cyclosporine (n = 18), or tacrolimus (n = 13). Clinical biochemistry, hematology, and OS parameters were measured on the day before KT and 1, 7, 30, and 90 days after KT.RESULTSOn the 7th day after KT, patients showed a significant decrease in AOPP (p = .0001) and TAS (p = .031) compared with the levels before KT. The decrease in AOPP levels lasted until the 90th day after KT. On the 90th day after KT, AOPP levels non‐significantly decreased in patients treated with tacrolimus compared with patients treated with cyclosporine (median was 70.35 µmol/L and 131.1 µmol/L).CONCLUSIONSuccessful KT reduced but did not normalize AOPP levels.
Entecavir treatment for chronic hepatitis B infection in end‐stage renal disease and kidney transplantation
Authors: Ridruejo Ezequiel , Adrover Raúl , Alonso Cristina , Mandó Oscar G. , Silva Marcelo O. 
Published: September 2010

AbstractBACKGROUNDThe prevalence of chronic hepatitis B virus (HBV) infection is high in patients with end‐stage renal disease and in kidney transplant recipients, and there is little experience with treatment using the newer antiviral drugs. The aim of this study was to assess the efficacy and safety of entecavir in HBV infection in this difficult‐to‐treat population.METHODSEleven male patients—1 with stage 4 chronic kidney disease, 7 undergoing hemodialysis, and 3 kidney transplant recipients‐were included in the study evaluation. Six were treatment naïve, and 5 were lamivudine resistant. Entecavir was administered at a dose of 0.1–1 mg qd according to the patients' renal function. All were HBsAg positive: 9 were HBeAg (+)/antiHBe (−), and the remaining 2 were HBeAg (−)/antiHBe (+).RESULTSAfter a median treatment of 2 ± 0.86 years, entecavir therapy was associated with a significant decrease in HBV DNA viral load: it was 6.84 ± 1.45 log10 UI/mL (range 5.21–9.04) at baseline and at the time of evaluation had dropped to 1.73 ± 2.11 log10 UI/mL (range <0.78–4.72). The rate of HBV DNA clearance was 54.5% (n = 6). The rate of anti–HBe seroconversion was 77.7% (7/9 HBeAg‐positive patients). The rate of anti‐HBs seroconversion was 9.1% (1/11 patients). There were no significant changes in renal function or hematological parameters.CONCLUSIONSThis small study demonstrates that entecavir therapy is safe and efficient in HBV‐positive patients with varying degrees of renal dysfunction.
Structural Characterization of Novel ortho‐Lithiated Imines
Authors: Beck John F. , Neshat Abdollah , Schmidt Joseph A. R. 
Published: September 2010

Abstractortho‐Metallated imines are commonly used as ligands for late transition metals. Unfortunately, not all metals, such as titanium, zirconium, and niobium, can undergo the necessary oxidative addition reactions to form the desired ortho‐metallated complexes directly. Therefore, a synthetic methodology allowing easy access to this binding mode from simple early transition metal halides via an ortho‐lithiated imine precursor is desirable. ortho‐Lithiation of benzylamines and othersystems has been well studied; in contrast, that of imines is poorly developed. However, inclusion of a 3,4‐methylenedioxy group on phenyl imines allows for straightforward lithiation and simple isolation of the ortho‐lithiated imines. NMR spectroscopy and single‐crystal X‐ray diffraction allowed for the structural elucidation of the clustering in these lithium complexes. It has been determined that the nature of the imine nitrogen substituent has a profound effect on the clustering of the lithiated imines. Alkyl (Cy, tBu) substituents clustered in a tetrameric form, whereas aryl (2,6‐R2C6H3; R = Me, Et, iPr) substituents formed dimers that exhibited long‐range ordering in the solid state as coordination polymers. The introduction of coordinating solvent, such as dimethoxyethane and diethyl ether, changed the long‐range order of the coordination polymer and in some cases, forced the formation of discrete dimeric lithium complexes. Lithium NMR spectroscopy indicates that in solution the coordination polymer breaks up to form discrete dimers. These complexes also display a pronounced decrease in the ring bond angle of the aromatic carbon atom directly attached to the lithium atom, which indicates an increase in the p‐character of the carbon–lithium bond.
Motivation to change in adolescents with bulimia nervosa mediates clinical change after treatment
Authors: Castro‐Fornieles Josefina , Bigorra Aitana , Martinez‐Mallen Esteve , Gonzalez Laura , Moreno Elena , Font Elena , Toro Josep 
Published: September 2010

AbstractSeveral studies have related motivation to change and treatment response in adult patients with bulimia nervosa but there are no longitudinal studies analysing this relationship in adolescents. The objective was to determine whether motivation to change is related to clinical improvement after treatment in adolescent patients with bulimia nervosa. The Bulimia Nervosa Stages of Change Questionnaire, the Eating Disorders Inventory (EDI‐2) and the Beck Depression Inventory (BDI) were administered at the beginning of treatment to 40 adolescent patients with bulimia nervosa (DSM‐IV) (mean age = 16.2 years). Thirty‐one patients were re‐assessed after 6 months of treatment. The majority of clinical and psychological variables improved significantly at the second evaluation. There were significant correlations between initial motivation to change and improvement in number of binges and the EDI‐2 scales of Bulimia and Interoceptive Awareness. In the stepwise multiple linear regression analysis, which included initial motivation to change and other potential confounding variables such as age, BDI, duration of disorder and body mass index, only motivation to change was selected as a predictor of improvement in number of binges (standardized β coefficient = 0.45; p = 0.012) and of decrease on the Bulimia scale (standardized β coefficient = 0.43; p = 0.029). Regarding improvement in Interoceptive Awareness, only the BDI score was selected as an independent predictor (β coefficient = 0.58; p = 0.002). In conclusion, in adolescent patients receiving treatment for bulimia nervosa, improvement in bulimic symptomatology seems to be especially related to initial motivation to change. Copyright © 2010 John Wiley & Sons, Ltd and Eating Disorders Association.
An aquatic toxicological evaluation of sulfate: The case for considering hardness as a modifying factor in setting water quality guidelines
Authors: Elphick James R , Davies Martin , Gilron Guy , Canaria Edmund C , Lo Bonnie , Bailey Howard C 
Published: September 2010

Abstract
Elevated concentrations of sulfate occur commonly in anthropogenically impacted and natural waters. However, water quality guidelines (WQG) have not been developed in many jurisdictions, and chronic toxicity data are scarce for this anion. A variety of test organisms, including species of invertebrate, fish, algae, moss, and an amphibian, were tested for chronic toxicity to develop a robust dataset that could be used to develop WQGs. As an example of how these data might be used to establish guidelines, calculations were performed using two standard procedures: a species sensitivity distribution (SSD) approach, following methods employed in developing Canadian WQGs, and a safety factor approach, according to procedures typically used in the development of provincial WQGs in British Columbia. The interaction of sulfate toxicity and water hardness was evaluated and incorporated into the calculations, resulting in separate values for soft (10–40 mg/L), moderately hard (80–100 mg/L) and hard water (160–250 mg/L). The resulting values were 129, 644, and 725 mg/L sulfate, respectively, following the SSD approach, and 75, 625, and 675 mg/L sulfate, following the safety factor approach. Environ. Toxicol. Chem. 2011;30:247–253. © 2010 SETAC