bluuebunny/crossref_metadata_2025_split huggingface dataset:
Construction of the Active Site of Metalloenzyme on Au NC Micelles
Authors: ZHANG Zhiming , FU Qiuan , HUANG Xin , XU Jiayun , LIU Junqiu , SHEN Jiacong 
Published: July 2009

AbstractFor developing an efficient nanoenzyme system with self‐assembly strategy, gold nanocrystal micelles (Au NC micelles) with inserted catalytic Zn(II) centers were constructed by self‐assembly of a catalytic ligand [N,N‐bis(2‐aminoethyl)‐N′‐dodecylethylenediamine] Zn(II) complexes (Zn(II)L) on the surface of Au NC via hydrophobic interaction. The functionalized Au NC micelles acted as an excellent nanoenzyme model for imitating ribonuclease. The catalytic capability of the Au NC micelles was evaluated by accelerating the cleavage of 2‐hydroxypropyl p‐nitrophenyl phosphate (HPNP). These functionalized Au NC micelles exhibited considerable ribonuclease‐like activities by a factor of 4.9×104 (kcat/kuncat) for the cleavage of HPNP in comparison to the spontaneous cleavage of HPNP at 37°C. The catalytic capability of the functionalized Au NC micelles can be considerably compared to other models reported previously as nanoenzymes under the comparable conditions.
Highly Efficient Conjugate Addition of Amines to Electron Deficient Alkenes Catalyzed by KF Supported on Metal Oxides
Authors: LIANG Xuezheng , ZHANG Jing , BAO Shaohua , YANG Jianguo 
Published: July 2009

AbstractA novel efficient procedure has been developed for the conjugate addition of amines to electron deficient alkenes. A series of KF supported on different carriers have been synthesized for the conjugate addition amines to alkenes. After optimizing the reaction conditions, KF/MgO was chosen as the most efficient catalyst for the reactions. The results showed that the catalyst was very efficient for the conjugate addition of amines to electron deficient alkenes with excellent yields in several minutes. Operational simplicity, no need of any solvent, low cost of the catalyst used, high yields, reusability, excellent chemoselectivity and wide applicability are the key features of this methodology.
Thermodynamic Study on Complex of Terbium with Glycine Tb(Gly)2Cl3·3H2O
Authors: LIU Beiping , TAN Zhicheng , ZHANG Jingnan , LÜ Xuechuan , ZHANG Dashun , CHEN Zhengan 
Published: July 2009

AbstractA terbium complex with glycine Tb(Gly)2Cl3·3H2O was synthesized and its IR spectrum was determined. The heat capacity of the complex was measured with a high‐precision automatic adiabatic calorimeter over the temperature range from 81 to 378 K. From 170 to 247 K, two solid‐solid phase transitions occurred at 186.054 and 244.063 K, respectively. Thermal decomposition of the complex was studied by thermogravimetric (TG) techniques and a possible mechanism for the decomposition was suggested. By isoperibol solution‐reaction calorimetry, the standard molar enthalpy of formation of Tb(Gly)2Cl3·3H2O was derived to be − (3109.5±3.1) kJ·mol−1.
Theoretical Investigation on the One‐ and Two‐photon Absorption Properties of Porphyrin‐thiophene Chromophores
Authors: LI Wenchao , FENG Jikang , REN Aimin , ZHANG Xiangbiao , SUN Chiachung 
Published: July 2009

AbstractTwo series of porphyrin‐thiophene chromophores were theoretically studied that exhibit large two‐photon absorption cross‐section in the visible region. The density functional theory (DFT) associated with ZINDO/SDCI methods has been used to calculate the molecular geometries, electronic structures, one‐photon and two‐photon absorption properties. The results show that the number of thiophene units affects the properties of one‐photon absorption (OPA) and two‐photon absorption (TPA). Porphyrin‐thiophene chromophores featuring two or three thiophene units have wide TPA response ranges; they can be applied to many nonlinear optical areas, such as optical limiting. Intervening ethynyl unit is beneficial to extend the conjugated pathway, and increase the two‐photon absorption cross‐section. At the same time, the OPA and TPA wavelengths are bathochromically shifted. From viewpoint of the high transparency and large nonlinear optical response, porphyrin‐thiophene chromophores will be promising TPA materials.
Syntheses, Structure, Magnetic Properties and 57Fe M?ssbauer Spectroscopies of Two Iron(II) Complexes: Room‐temperature Spin Crossover Behavior Observed in [Fe(dpq)(MePy)2(NCS)2]
Authors: TAO Jianqing , GU Yunlan , ZHOU Xinhui , GU Zhiguo , ZUO Jinglin , YOU Xiaozeng 
Published: July 2009

AbstractTwo new complexes [Fe(dpq)(MePy)2(NCS)2] (1) and [Fe(Medpq)(MePy)2(NCS)2] (2) (dpq=2‐dipyrido[3,2‐f: 2′,3′‐h]quinoxaline, Medpq=2‐methyldipyrido[3,2‐f:2′,3′‐h]quinoxaline, MePy=4‐methylpyridine) have been synthesized. The crystal structure of 2 was characterized by X‐ray diffraction at room temperature. It crystallizes in orthorhombic space group I212121, with a=15.057(3) Å, b=14.569(3) Å, c=13.180(3) Å, α =90.00°, β=90.00°, γ=90.00°, and V=2891.2(11) Å3. The distorted [FeN6] octahedron in 2 is formed by six nitrogen atoms from Medpq, two trans‐MePy molecules and two cis‐NCS− anions. Variable‐temperature magnetic susceptibilities and M?ssbauer spectroscopies of 1 and 2 reveal the occurrence of a gradual spin transition. The transition for 1 spans the 200–450 K temperature range with a T1/2 of 340 K, while for 2, the transition in low temperature is incomplete.
Sol‐gel Preparation of CNT/ZnO Nanocomposite and Its Photocatalytic Property
Authors: WANG Xuejing , YAO Shuwen , LI Xiaobo 
Published: July 2009

AbstractUsing carbon nanotubes (CNT) as templete, CNT/ZnO nanocomposite was prepared by a sol‐gel method. Its structure was characterized by XRD, IR and TEM. The UV absorbing properties were detected by a UV spectrophotometer. Photo degradation of methyl red in aqueous solution was investigated by using CNT/ZnO nanocomposite as photocatalyst. The results showed that the nanocomposite was composed of carbon nanotubes coated evenly by ZnO particles, with a diameter of 50–60 nm. UV‐vis spectra indicated that the as‐prepared CNT/ZnO nanocomposite had absorption of visible light as well as ultraviolet light. 60% CNT‐added nanocomposite had the highest degradation rate for methyl red under the sunlight irradiation.
Resonance Scattering Spectral Determination of Trace Penicillin G Using Immunonanogold‐HAuCl4‐NH2OH Catalytic Reaction
Authors: WEN Guiqing , LI Yan , LIANG Aihui , JIANG Zhiliang 
Published: July 2009

AbstractBoth nanogold and immunonanogold exhibit catalytic effect on the slow reaction of HAuCl4‐NH2OH to form gold particles which displayed a resonance scattering (RS) peak at 580 nm. Using hapten penicillin G (PG) as a model, the nanogold in size of 9 nm was used to label rabbit anti‐penicillin G antisera (RAPG) to obtain an immunonanogold probe (AuRAPG) for PG. The PG was combined with AuRAPG to form the immunocomplex and bigger nanogold clusters. After centrifugation, the excess AuRAPG in the supernatant exhibited catalytic effect on the reaction of HAuCl4‐NH2OH, and the RS intensity at 580 nm (I580 nm) was enhanced greatly. With the addition of PG, the I580 nm decreased accordingly. Under the optimal conditions, the decreased intensity ΔI580 nm was proportional to the PG concentration in the range of 0.15–225 ng/mL, with a detection limit of 0.05 ng/mL for PG.
Generation of Pd Nanoparticles in situ from PdCl2 in TBAF: An Efficient and Reusable Catalytic System for the Suzuki‐Miyaura Reaction under Ligand‐ and Solvent‐free Conditions
Authors: TAO Liming , XIE Yexiang , DENG Chenliang , LI Jinheng 
Published: July 2009

AbstractPd nanoparticles were generated in situ from PdCl2 in TBAF (n‐Bu4NF), which displayed high efficiency for the Suzuki‐Miyaura cross‐coupling reaction. In the presence of PdCl2 and TBAF, a variety of aryl halides were coupled with arylboronic acids smoothly in moderate to good yields. Moreover, the PdCl2/TBAF system could be recovered and reused several times in the Suzuki‐Miyaura reaction, and aryl bromides could be consumed completely by arylboronic acids in about 15–60 min. It is noteworthy that these reactions were conducted under solvent‐free, ligand‐free and reusable conditions. Mechanism for the PdCl2/TBAF‐catalyzed reactions was also discussed.
Synthesis and Cytotoxicity of Derivatives of Fluorouracil Conjugated with Three‐membered Ring
Authors: WANG Le , ZHANG Yunxiao , TAO Jingchao 
Published: July 2009

AbstractA novel series of 3‐membered ring fluorouracil conjugates including cyclopropylmethyl fluorouracil and (2,3‐epoxypropyl) fluorouracil conjugates were synthesized via selective protection, and their structures were confirmed by IR, 1H NMR and HRMS. Cytotoxicities in vitro of these conjugates were evaluated. Compounds 7, 8, 12 and 13 have shown cytotoxicities against Ec9706 cells in different degrees.
A Concise Synthesis of (±)‐Yaequinolone A2
Authors: LI Xinyun , HUO Xing , LI Junpeng , SHE Xuegong , PAN Xinfu 
Published: July 2009

AbstractA concise total synthesis of (±)‐yaequinolone A2 (2), a 2‐quinolone alkaloid, has been accomplished through 6 steps from anthranilic acid with an overall yield of 27.8%. The synthetic strategy exploits highly diastereoselective intramolecular aldol addition of the MOM protected α‐hydroxyanilide 7 as the key step.
A Novel Palladium‐catalyzed Amination of Aryl Halides with Amines Using rac‐P‐Phos as the Ligand
Authors: CHEN Huansheng , WANG Quanrui , TAO Fenggang 
Published: July 2009

AbstractAn efficient palladium‐catalyzed amination of aryl halides with amines, using rac‐P‐Phos as the ancillary ligand and Pd(OAc)2 as the palladium source is developed. The ligand and all of the synthetic intermediates are stable to air and moisture, allowing the easy handling. The catalyst system performed well for a large number of different substrate combinations in 80–110°C to furnish aromatic amines in high yields.
A Convenient Method to Construct Chroman Skeleton: Asymmetric Synthesis of (−)‐4′‐Hydroxy‐7‐methoxyflavane
Authors: XU Boyan , XUE Jijun , ZHANG Huabing , LI Ying 
Published: July 2009

AbstractThe first enantioselective synthesis of a naturally occurring 4′‐hydroxy‐7‐methoxyflavane was developed by an asymmetric reduction and a microwave‐assistant aromatic C–O bond formation to construct the benzopyran skeleton. Key features of this method include its brevity, its preserved stereochemical integrity and two different synthetic routes to choose.
A New Route to Biaryl Ketones via Carbonylative Suzuki Coupling Catalyzed by MCM‐41‐supported Bidentate Phosphine Palladium(0) Complex
Authors: ZHENG Guomin , WANG Pingping , CAI Mingzhong 
Published: July 2009

AbstractA variety of biaryl ketones can be conveniently synthesized in good to high yields via the first heterogeneous carbonylative Suzuki coupling of arylboronic acids with aryl iodides under atmospheric pressure of carbon monoxide in the presence of a catalytic amount of MCM‐41‐supported bidentate phosphine palladium(0) complex [MCM‐41‐2P‐Pd(0)]. This polymeric palladium catalyst can be reused at least 10 times without any decrease in activity.
Regio‐specific Microbial Hydroxylation of Phytolaccagenin by Streptomyces griseus ATCC 13273
Authors: QIAN Liwu , ZHANG Jian , LIU Jihua , YU Boyang 
Published: July 2009

AbstractMicrobial transformation of one oleane‐type pentacyclic triterpene aglycone, phytolaccagenin (2β,3β,23‐trihydroxy‐olean‐12‐ene‐28,30‐dioic acid 30‐methyl ester) by Streptomyces griseus ATCC 13273 was investigated for developing new bioactive derivatives. A new oxidized metabolite, through the regio‐specific hydroxylation on the C‐29 methyl group, was obtained from the preparative‐scale biotransformation with a standard two‐stage fermentation protocol. The metabolite was identified as 2β,3β,23,29‐tetrahydroxy‐olean‐12‐ene‐28,30‐dioic acid 30‐methyl ester by mass and 2D‐NMR spectra.
A Second Generation of Carbamate‐Based Fatty Acid Amide Hydrolase Inhibitors with Improved Activity in vivo
Authors: Clapper Jason R. , Vacondio Federica , King Alvin R. , Duranti Andrea , Tontini Andrea , Silva Claudia , Sanchini Silvano , Tarzia Giorgio , Mor Marco , Piomelli Daniele 
Published: July 2009

AbstractThe fatty acid ethanolamides are a class of signaling lipids that include agonists at cannabinoid and α type peroxisome proliferator‐activated receptors (PPARα). In the brain, these compounds are primarily hydrolyzed by the intracellular serine enzyme fatty acid amide hydrolase (FAAH). O‐aryl carbamate FAAH inhibitors such as URB597 are being evaluated clinically for the treatment of pain and anxiety, but interactions with carboxylesterases in liver might limit their usefulness. Here we explore two strategies aimed at overcoming this limitation. Lipophilic N‐terminal substitutions, which enhance FAAH recognition, yield potent inhibitors but render such compounds susceptible to attack by broad‐spectrum hydrolases and inactive in vivo. By contrast, polar electron‐donating O‐aryl substituents, which decrease carbamate reactivity, yield compounds, such as URB694, that are highly potent FAAH inhibitors in vivo and less reactive with off‐target carboxylesterases. The results suggest that an approach balancing inhibitor reactivity with target recognition produces FAAH inhibitors that display significantly improved drug‐likeness.
The Relevance of Polar Surface Area (PSA) in Rationalizing Biological Properties of Severalcis‐Diamminemalonatoplatinum(II) Derivatives
Authors: Caron Giulia , Ermondi Giuseppe , Gariboldi Marzia B. , Monti Elena , Gabano Elisabetta , Ravera Mauro , Osella Domenico 
Published: July 2009

AbstractA panel of sixcis‐diamminemalonatoplatinum(II) derivatives were designed and synthesized, and their physicochemical properties and in vitro biological activity were experimentally evaluated and studied in silico. All the complexes showed higher IC50values (≥20 μM) than those observed for cisplatin and its malonato analogue on three different human tumor cell lines, namely A2780 ovarian carcinoma, A549 lung carcinoma, and MCF‐7 breast carcinoma. In silico studies revealed that polar surface area (PSA) is the best descriptor to explain the poor biological activity observed for this series of new compounds, which in turn is likely due to poor cellular uptake. This finding is in line with general rules that assign a major role to PSA in characterizing the transport properties of drugs, in the actual case of antiproliferative metallopharmaceuticals.
2,3‐Dihydro‐1‐Benzofuran Derivatives as a Series of Potent Selective Cannabinoid Receptor 2 Agonists: Design, Synthesis, and Binding Mode Prediction through Ligand‐Steered Modeling
Authors: Diaz Philippe , Phatak Sharangdhar S. , Xu Jijun , Fronczek Frank R. , Astruc‐Diaz Fanny , Thompson Charles M. , Cavasotto Claudio N. , Naguib Mohamed 
Published: July 2009

AbstractWe recently discovered and reported a series ofN‐alkyl‐isatin acylhydrazone derivatives that are potent cannabinoid receptor 2 (CB2) agonists. In an effort to improve the druglike properties of these compounds and to better understand and improve the treatment of neuropathic pain, we designed and synthesized a new series of 2,3‐dihydro‐1‐benzofuran derivatives bearing an asymmetric carbon atom that behave as potent selective CB2agonists. We used a multidisciplinary medicinal chemistry approach with binding mode prediction through ligand‐steered modeling. Enantiomer separation and configuration assignment were carried out for the racemic mixture for the most selective compound, MDA7 (compound18). It appeared that theS enantiomer, compound MDA104 (compound33), was the active enantiomer. Compounds MDA42 (compound19) and MDA39 (compound30) were the most potent at CB2. MDA42 was tested in a model of neuropathic pain and exhibited activity in the same range as that of MDA7. Preliminary ADMET studies for MDA7 were performed and did not reveal any problems.
Esophagectomy compared with chemoradiation for early stage esophageal cancer in the elderly
Authors: Abrams Julian A. , Buono Donna L. , Strauss Joshua , McBride Russell B. , Hershman Dawn L. , Neugut Alfred I. 
Published: July 2009

AbstractBACKGROUND:Esophagectomy has been the traditional treatment of choice for early stage esophageal cancer. However, esophagectomy is associated with high mortality and morbidity in the elderly, and these patients often receive chemoradiation instead. The authors of this report compared outcomes of esophagectomy versus chemoradiation in a population‐based sample of elderly patients with early stage esophageal cancer.METHODS:The Surveillance, Epidemiology, and End Results‐Medicare database was used to identify patients aged ≥65 years who were diagnosed with stage I or II esophageal cancer from 1991 to 2002. The associations of treatment with esophagectomy or chemoradiation were assessed along with demographic and clinical variables. A survival analyses was performed to compare outcomes with treatment modality and was adjusted for potential confounders.RESULTS:Seven hundred thirty patients with stage I or II esophageal cancer were identified who underwent esophagectomy (n = 341; 46.7%) or chemoradiation (n = 389; 53.3%). Older age, squamous cell histology, and lower socioeconomic status were associated with increased odds of receiving chemoradiation. In multivariate analyses, chemoradiation was associated with worse disease‐specific survival (hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.64‐2.64) and overall survival (HR, 1.92; 95%CI, 1.58‐2.34). The receipt of chemoradiation was associated with worse survival for patients with adenocarcinoma (HR, 3.01; 95%CI, 2.24‐4.04), but there was no significant difference for patients with squamous cell carcinoma (HR, 1.33; 95%CI, 0.98‐1.80).CONCLUSIONS:Compared with chemoradiation, esophagectomy may be associated with improved survival for early stage esophageal cancer in the elderly. The current results suggest that there also may be a subset of patients with squamous cell carcinoma for whom chemoradiation is adequate therapy. A randomized trial would be useful to determine the optimal treatment for elderly patients with early stage esophageal cancer. Cancer 2009. © 2009 American Cancer Society.
Lambda calculus as a workflow model
Authors: Kelly Peter M. , Coddington Paul D. , Wendelborn Andrew L. 
Published: July 2009

AbstractData‐oriented workflows are often used in scientific applications for executing a set of dependent tasks across multiple computers. We discuss how these can be modeled using lambda calculus, and how ideas from functional programming are applicable in the design of workflows. Such an approach avoids the restrictions often found in workflow languages, permitting the implementation of complex application in logic and data manipulation. This paper explains why lambda calculus is an appropriate model for workflow representation, and how a suitably efficient implementation can provide a wide range of capabilities to developers. The presented approach also permits high‐level workflow features to be implemented at user level, in terms of a small set of low‐level primitives provided by the language implementation. Copyright © 2009 John Wiley & Sons, Ltd.
Decentralized guaranteed cost control for uncertain large‐scale systems using additive control gain
Authors: Mukaidani Hiroaki , Kimoto Minoru 
Published: July 2009

AbstractThis paper investigates an application of additive control gain to the guaranteed cost control (GCC) problem of decentralized robust control for a class of discrete‐time uncertain large‐scale systems. Based on the Linear Matrix Inequality (LMI) design approach, a class of decentralized local fixed state feedback controllers with additive control gain is established. The novel contribution of this paper is that multiobjective control is attained by using the additive control gain. Although the additive control gain is included in the uncertain large‐scale systems, the closed‐loop system is asymptotically stable. In order to demonstrate the efficiency of our proposed controller, using the fuzzy logic control as the additive control gain, the simple numerical example is given. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 18–32, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20726
Influence of catalyst and gas diffusion layer degradation on flooding in pefc
Authors: Hiramitsu Yusuke , Hayashi Yoshihiko , Kobayashi Kenji , Hori Michio 
Published: July 2009

AbstractWith respect to polymer electrolyte fuel cells (PEFC), degradation of the catalyst and gas diffusion layers, which are parts of the membrane electrode assembly (MEA), and its influence on electrode flooding were investigated. High‐humidity operation is desirable for high performance of a PEFC, because the proton exchange membrane and ionomer at the catalyst layer must hold a large amount of water. Additionally, high gas utilization is necessary for high system efficiency. However, under these conditions, the cell performance is significantly degraded by water flooding of the electrodes. A PEFC single cell was operated at 0.3 A/cm2 at high humidity for 10,000 h, and the cell performance was evaluated in terms of the cell potential, cell resistance, IV characteristics, crossover rate, effective chemical surface area, and oxygen gain, in order to determine the parts of the cell that play a dominant role in cell degradation. Degradation of gas diffusivity was found to dominate the degradation of cell performance, and it was found to occur mainly in the catalyst layer rather than in the gas diffusion layer. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 10–17, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20899
An engine control systems design for low‐emission vehicles by generalized predictive control based on identified model
Authors: Hashimoto Seiji , Okuda Hiroyuki , Okada Yasushi , Adachi Shuichi , Niwa Shinji , Kajitani Mitsunobu 
Published: July 2009

AbstractConservation of the environment has become critical to the automotive industry. Recently, requirements for on‐board diagnostic and engine control systems have been strictly enforced. In the present paper, in order to meet the requirements for low‐emission vehicles, a novel method for construction of the air‐fuel ratio (A/F) control system is proposed. The method of construction of the system is divided into two steps. The first step is to design the A/F control system for the engine based on an open loop design. The second step is to design the A/F control system for the catalyst system. The design method is based on generalized predictive control in order to assure robustness to open loop control as well as model uncertainty. The effectiveness of the proposed A/F control system is verified through experiments using full‐scale products. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 47–55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20907