bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design, Synthesis, and Bioevaluation of Novel Strobilurin Derivatives
Authors: Zhu Xiaolei , Wang Fu , Li Hui , Yang Wenchao , Chen Qiong , Yang Guangfu 
Published: September 2012

AbstractStrobilurins are one of the most important natural products with fungicidal activities and well known for their novel action mode, broad fungicidal spectrum, lower toxicity against mammalian cells, and environmentally benign characteristics. Design and syntheses of strobilurin analogues therefore have attracted great attention in the field of agrochemistry. Previously, we successfully developed a new molecular design method of pharmacophore‐linked fragment virtual screening (PFVS) and discovered a lead compound (E)‐methyl‐2‐(2‐(((3‐(imino‐(phenyl)methyl)phenyl)thio)methyl)phenyl)‐3‐methoxyacrylate (1). To discover new strobilurin analogues with higher fungicidal activity, the structural modification of compound 1 was carried out guided by bioisosterism. A series of benzophenone derivatives 2a–2j were synthesized, among which compound 2j with a Ki value of 1.89 nmol/L was identified as the most promising inhibitor of porcine cytochrome bc1 complex, 157‐fold improved binding affinity compared to the commercially available bc1 inhibitor Azoxystrobin (AZ). In addition, most of the new compounds displayed excellent fungicidal activity against Sphaerotheca fuliginea at the concentration of 200 µmol/L. The present work indicates that strobilurin analogues containing benzophenone side chains may be the ideal leads for future fungicide discovery.
Highly Efficient Oxidative Cleavage of Carbon‐Carbon Double Bond over meso‐Tetraphenyl Cobalt Porphyrin Catalyst in the Presence of Molecular Oxygen
Authors: Zhou Xiantai , Ji Hongbing 
Published: September 2012

AbstractHighly efficient and selective carbon‐carbon double bond aerobic cleavage of olefins catalyzed by metalloporphyrins was investigated, and carbonyl compounds and epoxide were produced as the main products. CoTPP (cobalt meso‐tetraphenyl porphyrin) showed excellent activity for the oxidative cleavage of carbon‐carbon double bond by using styrene as model compound, in which the TOF (turnover frequency) and selectivity toward benzaldehyde was obtained with 2×104 h−1 and 86%, respectively.
RAFT Copolymerization of Glycidyl Methacrylate and N,N‐Dimethylaminoethyl Methacrylate
Authors: Cao Jun , Zhang Lifen , Pan Xiangqiang , Cheng Zhenping , Zhu Xiulin 
Published: September 2012

AbstractIn this work, copolymerization of two functional monomers, glycidyl methacrylate (GMA) and N,N‐dimethylaminoethyl methacrylate (DMAEMA), was firstly carried out via reversible addition‐fragmentation chain transfer (RAFT) polymerization successfully. The copolymerization kinetics was investigated under the molar ratio of n[GMA+DMAEMA]0/n[AIBN]0/n[CPDN]0=300/1/3 at 60°C. The copolymerization showed typical "living" features such as first‐order polymerization kinetics, linear increase of molecular weight with monomer conversion and narrow molecular weight distribution. The reactivity ratios of GMA and DMAEMA were calculated by the extended Kelen‐Tüdös linearization methods. The epoxy group of the copolymer PGMA‐co‐PDMAEMA remained intact under the conditions of RAFT copolymerization and could easily be post‐modified by ethylenediamine. Moreover, the modified copolymer could be used as a gene carrier.
One‐Pot Terpolymerization of CO2, Propylene Oxide and Lactide Using Rare‐earth Ternary Catalyst
Authors: Gu Lin , Qin Yusheng , Gao Yonggang , Wang Xianhong , Wang Fosong 
Published: September 2012

AbstractA convenient one‐pot terpolymerization of CO2, propylene oxide (PO), and L‐lactide (L‐LA) in short polymerization time (10 h or shorter) to afford poly(propylene carbonate‐lactide) with excellent mechanical property and thermal stability using Y(CCl3COO)3‐ZnEt2‐glycerin rare‐earth ternary catalyst is reported. The yield of the copolymerization was between 69.7 and 111.7 g/(g Zn), corresponding to L‐LA/PO molar feed ratio varying from 0 to 0.1, and the number average molecular weight was between 5.5×104 and 11.9×104. The L‐LA content in the terpolymer increased from 1.1% to 34.7% when L‐LA/PO molar feed ratio changed from 0.01 to 0.1. Introducing L‐LA as the third comonomer could significantly improve the mechanical strength and thermal stability of PPC. For the terpolymer obtained from L‐LA/PO molar feed ratio of 1:50, the elongation at break reached 40.5%, which is 3 times of that of pure PPC, and the thermal decomposition temperature increased by 32°C compared with pure PPC.
Enhancement of Alkene Epoxidation Activity of Titanosilicates by Gas‐Phase Ammonia Modification
Authors: Zhang Liyan , Xu Le , Sun Jingjing , Jiang Jingang , Liu Yueming , Wu Haihong , Wu Peng 
Published: September 2012

AbstractNovel ammonia‐treated titanosilicates have been prepared by heating the samples of Ti‐MWW, TS‐1 and Ti‐Beta under pure ammonia gas flow at 673 K for a period of time. The ammonia modification improved their catalytic performance in liquid‐phase oxidations. Especially, the catalytic activities of ammonified Ti‐MWW, N‐Ti‐MWW, were enhanced greatly in the epoxidation of 1‐hexene with H2O2. The reason that the ammonia treatment played such an important role in post‐modification of titanosilicate was investigated in details. In comparison to the parent Ti‐MWW catalyst, N‐Ti‐MMW was more robust and produced less coke in oxidation reactions.
Facile Synthesis of Chiral Diphosphine‐Containing Multiple Dendrimeric Catalysts for Enantioselective Hydrogenation
Authors: Zhao Liwen , Liu Ji , Feng Yu , He Yanmei , Fan Qinghua 
Published: September 2012

AbstractA new kind of chiral diphosphine PyrPhos‐functionalized codendrimers have been synthesized via a liquid‐phase strategy in high yields. The resulting dendrimeric PyrPhos ligands were purified by a simple solvent precipitation without the need for chromatographic separation, and well characterized by 1H, 13C and 31P NMR, MALDI‐TOF mass spectroscopy as well as elemental analysis. Their rhodium complexes were applied to the asymmetric hydrogenation of α‐acetamido cinnamic acids. Excellent enantioselectivities were achieved, which are comparable to those with the corresponding small molecular catalysts. In addition, these codendrimeric catalysts showed better catalytic performance than the dendrimeric catalysts with Rh(PyrPhos) sites located in the focal point of poly(aryl ether) dendrons or in the periphery of poly(propyleneimine) dendrimers.
Synthesis and Properties of Quaternary Phosphonium‐based Anion Exchange Membrane for Fuel Cells
Authors: Jiang Lihua , Lin Xiaocheng , Ran Jin , Li Chuanrun , Wu Liang , Xu Tongwen 
Published: September 2012

AbstractQuaternary phosphonium‐based polyelectrolyte was synthesized from bromomethylated poly(2,6‐dimethyl‐1,4‐ phenylene oxide) (BPPO) by functionalization with tris(2,4,6‐trimethoxyphenyl) phosphine (TTMPP). Typically, excellent solubility of the polyelectrolyte in polar solvents, such as NMP and DMSO, allowed a solution‐casting strategy for preparation of anion exchange membrane (AEM) with properly ordered hydrophilic/hydrophobic nano‐scale phase separation morphology, which was visible in atomic force microscopic phase images. Accordingly, the optimized ionmeric AEM exhibited excellent hydroxide conductivity of 110 mS/cm at 70°C, but extremely restricted linear expansion ratio of below 7% at the same temperature. Additionally, such membrane could maintain flexibility and conductivity after an immersion treatment in 1 mol/L NaOH solution at 60°C for about 100 h, implying its potential in alkaline fuel cells.
Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip
Authors: Liu Yingyi , Yu Jie , Chen Wenwen , Liu Dingbin , Wang Zhuo , Jiang Xingyu 
Published: September 2012

AbstractWe have developed a microfluidic chip for colorimetric Cu2+ detection. In this chip, it is facile to do colorimetric Cu2+ detection based on gold nanoparticles. This method has a dynamic detection range from 0.75 to 50 µmol/L with only 20 µL solution including detection reagents and sample. The result can be readout by naked eye and photographed by digital cameras. With the help of image processing software, we could measure the RGB value and calculate the Blue/Red ratio for more accurate quantification. Tap water could be detected in this portable chip.
Odd‐Even Sequence Effect of Surface‐Mediated Peptide Assemblies Observed by Scanning Tunneling Microscopy
Authors: Guo Yuanyuan , Wang Chenxuan , Hou Jingfei , Yang Aihua , Zhang Xuemei , Wang Yibing , Zhang Min , Yang Yanlian , Wang Chen 
Published: September 2012

AbstractThe peptide assembly structures of polyglutamine (PolyQ) have been studied by using scanning tunneling microscopy (STM) with high spatial resolution in ambient conditions. 4,4′‐Bipyridyl (4Bpy) was introduced into the PolyQ7 and PolyQ8 peptide assemblies for labeling the C‐termini of the peptides. The fine structures of the 4Bpy‐PolyQ7 and 4Bpy‐PolyQ8 co‐assemblies are observed, and the statistics of the apparent peptide strand length reveal different length distributions for PolyQ7 and PolyQ8. One predominant apparent peptide strand length is observed for PolyQ7 reflecting one predominant peptide conformation in assembly structures, while three major apparent strand lengths can be identified with PolyQ8 reflecting three co‐existing peptide conformations in peptide assemblies. Such drastic difference in assembling characteristics can be considered as a reflection of asymmetric adsorption effect of peptides relating to odd‐even residue numbers of PolyQ7 and PolyQ8.
A Short and Flexible Synthetic Approach to the Naturally Occurring Racemic Neoclausenamide and Its Analogs
Authors: Dai Xijie , Huang Peiqiang 
Published: September 2012

AbstractA novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro‐selective vinylogous Mukaiyama type reaction (dr=12:1) and a highly diastereoselective tandem conjugate addition‐Davis oxidation of N‐Boc‐pyrrol‐2(5H)‐one 5 (dr=10:1). Remarkably, the skeleton of neoclausenamide, namely 8a, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers (relative stereochemistry) established correctly and in excellent diastereoselectivities.
Biomedical Effects and Nanosafety of Engineered Nanomaterials: Recent Progress
Authors: Wang Xiaofeng , Zhu Motao , Li Jingyuan 
Published: September 2012

AbstractWith the development of nanotechnology, there are growing concerns about biological effects and biosafety of engineered nanomaterials. On the other hand, nanoparticles are widely used in medical fields based on their novel interactions with biological entities. However, there are still a lot of challenges to establish systematic knowledge about nanotoxicology and develop biologically safer biomedical materials due to the variety of factors determining their biomedical effects and nanotoxicity. Understanding the interactions of engineered nanomaterials with the biological entities becomes crucial to the further development of nanoscience and nanotechnology. In the past decade, colleagues in our laboratory intensively studied the toxic properties of various kinds of nanomaterials and their chemical mechanisms. In this paper we review the recent advance in the research on the biological effects of engineered nanomaterials and nanosafety issue, by focusing on the studies about representative nanomaterials in our laboratory.
Initial Decomposition of Methanol and Water on In2O3(110): A Periodic DFT Study
Authors: Lin Sen , Xie Daiqian 
Published: September 2012

AbstractPure In2O3 is considered as an efficient methanol steam reforming catalyst. Despite of several studies in the past decades, the mechanism of MSR on In2O3 is still not fully understood. In this work, a periodic density functional theory study of the initial dissociation of methanol and water over the In2O3 (110) surface is presented. The activation energy barriers and thermochemistry for several elementary steps are reported. It is found that the energy barriers for OH bond cleavage of both CH3OH and H2O to produce CH3O and OH species at a surface In‐O pair site are very low, indicating that In2O3 (110) can facilely catalyze these two important processes at low temperatures. In addition, the subsequent dehydrogenation of CH3O to CH2O is also found to proceed with a low barrier.
Synthesis and Structure of Supramolecular Compound with Ethyl 2‐(4‐Aminophenoxy)acetate Based on 18‐Crown‐6
Authors: Wang Wenxiang , Sun Suwen , Xiong Rengen 
Published: September 2012

AbstractThe title ammonium compound ethyl 2‐(4‐aminophenoxy)acetate (C10H13NO3, I) and its crown ether inclusion complex {[(C10H14NO3)·(18‐crown‐6)]+[PF6]−, II} (18‐crown‐6=1,4,7,10,13,16‐hexaoxacyclo‐octadecane) were synthesized. The ammonium compound I was determined by 1H NMR, IR and ESI‐MS techiniques. X‐ray crystallography reveals that compound I crystallizes in the triclinic system with space group of P‐1, all the atoms in I are almost coplanar except H, and NH···O hydrogen bonds lead to the formation of one dimensional chain. The rotator‐stator‐like compound II was crystallizes in the centrosymmetric monoclinic system with space group of P21/c. The supramolecular was formed via NH···O hydrogen‐bond interactions. Temperature‐dependent dielectric constants of compound II were measured.
Structural Studies on 4,5‐Disubstituted 2‐Aminoimidazole‐Based Biofilm Modulators that Suppress Bacterial Resistance to β‐Lactams
Authors: Su Zhaoming , Yeagley Andrew A. , Su Rui , Peng Lingling , Melander Christian 
Published: September 2012

AbstractA library of 4,5‐disubstituted 2‐aminoimidazole triazole amide (2‐AITA) conjugates has been successfully assembled. Upon biological screening, this class of small molecules was discovered as enhanced biofilm regulators through non‐microbicidal mechanisms against methicillin‐resistant Staphylococcus aureus (MRSA) and multidrug‐resistant Acinetobacter baumannii (MDRAB), with active concentrations in the low micromolar range. The library was also subjected to synergism and resensitization studies with β‐lactam antibiotics against MRSA. Lead compounds were identified that suppress the antibiotic resistance of MRSA by working synergistically with oxacillin, a β‐lactam antibiotic resistant to penicillinase. A further structure–activity relationship (SAR) study on the parent 2‐AITA compound delivered a 2‐aminoimidazole diamide (2‐AIDA) conjugate with significantly increased synergistic activity with oxacillin against MRSA, decreasing the MIC value of the β‐lactam antibiotic by 64‐fold. Increased anti‐biofilm activity did not necessarily lead to increased suppression of antibiotic resistance, which indicates that biofilm inhibition and resensitization are most likely occurring via distinct mechanisms.
Relativistic and Non‐Relativistic Electronic Molecular‐Structure Calculations for Dimers of 4p‐, 5p‐, and 6p‐Block Elements
Authors: Höfener Sebastian , Ahlrichs Reinhart , Knecht Stefan , Visscher Lucas 
Published: September 2012

AbstractWe report results of non‐relativistic and two‐component relativistic single‐reference coupled‐cluster with single and double and perturbative triple excitations [CCSD(T)] treatments for the 4p‐block dimers Ga2 to Br2, the 5p‐block dimers In2 to I2, and their atoms. Extended basis sets up to pentuple zeta are employed and energies extrapolated to the complete basis‐set limit. Relativistic and non‐relativistic results for the dissociation energy De are in close agreement with each other and previously published data, provided non‐relativistic or scalar‐relativistic results are corrected for spin–orbit contributions taken from the literature. An exception is Te2 where theoretical results scatter by 0.085 eV. By virtue of this agreement it is unexpected that comparison with the experimental D0 or De dissociation energies (zero‐point vibrational effects are negligible in this context) reveal errors larger than 0.1 eV for Ga2, Ge2, and Sb2. Only relativistic treatments are presented for the 6p‐block cases Tl2 to At2. Sufficient agreement with experimental data is found only for Pb2 and Bi2, the deviation of the computed and experimental D0 values for Po2 is again larger than 0.1 eV. Deviations of 0.1 eV between the computed and experimental D0 values are a major reason for concern and call for additional investigations in both fields to clarify the situation.
Highly Asymmetric Tribenzonaphtho‐Condensed Porphyrazinatozinc Complex: An Efficient Near‐Infrared Sensitizer for Dye‐Sensitized Solar Cells
Authors: Yu Lijuan , Zhou Xiaole , Yin Yinghui , Liu Yuwen , Li Renjie , Peng Tianyou 
Published: September 2012

AbstractNovel, highly asymmetric zinc phthalocyanine (ZnPc) derivatives (Zn‐tri‐PcNc) containing tribenzonaphtho‐condensed porphyrazine with one carboxyl and three tert‐butyl (tBu) or n‐butoxy (nBuO) peripheral substituents were synthesized by using 6‐carboxymethyl‐2,3‐dicyanonaphthalene and 4‐tBu‐ or nBuO‐phthalonitrile as starting agents. The new, highly asymmetric ZnPc containing tBu groups (Zn‐tri‐PcNc‐2 b) yielded a 3.56 % conversion efficiency in sensitizing TiO2‐based dye‐sensitized solar cells (DSSCs) under simulated AM 1.5G solar irradiation (100 mW cm−2), which is higher than that of the nBuO‐containing analogue Zn‐tri‐PcNc‐3 b (2.20 %). Moreover, Zn‐tri‐PcNc‐2 b displays 60.7 % of the maximum incident monochromatic photon‐to‐current conversion efficiency (IPCE) in the red/near‐IR region, which is much higher than that of Zn‐tri‐PcNc‐3 b (22.9 %), thus highlighting the potential of Zn‐tri‐PcNc‐2 b as a DSSC component.
Suppressing harmonics in four‐quadrant AC‐DC converters with chaotic SPWM control
Authors: Li Hong , Li Zhong , Lin Fei , Zhang Bo 
Published: September 2012

ABSTRACTIn this paper, a new chaotic sinusoidal pulse width modulation (chaotic SPWM) control is proposed and implemented in a four‐quadrant AC‐DC converter for harmonics suppression, where a chaotic carrier plays a key role. Further, the relationship of the harmonic distribution and carrier frequency is derived by analyzing the harmonic components of the AC‐DC converter, which is useful for revealing the operation principle of the chaotic SPWM control for harmonic suppression. Finally, the simulation and experimental results illustrate the effectiveness of the proposed chaotic SPWM control on harmonics reduction. Copyright © 2012 John Wiley & Sons, Ltd.
Electron Temperature Measurement in a Premixed Flat Flame Using the Double Probe Method
Authors: Wild J. , Kudrna P. , Tichý M. , Nevrlý V. , Střižík M. , Bitala P. , Filipi B. , Zelinger Z. 
Published: September 2012

AbstractThe electron temperatures Te were measured using a double probe in a premixed methane flame produced by a calibration burner according to Hartung et al. The experiment was performed at atmospheric pressure. In contrast to other authors, we have managed to find typical nonlinearities corresponding to the retarding electron current region and to calculate electron temperatures using a suitable fit on the basis of the measured characteristics. A Pt‐Rh thermocouple was used to measure temperatures Th corresponding to “heavy” species. Our results indicate that the flame plasma can be considered to be weakly non‐isothermic — Te = (2400–4000) K, Th = (1400–1600) K. On the basis of measurement of the saturated ion current, the number density of the charged particles was estimated at (0.3–3.8) · 1017 m‐3. The trends in Te and Th in dependence on the positions of the probes and thermocouple in the flame differ substantially; this fact has not yet been explained (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deciduoid mesothelioma: Cytologic presentation and diagnostic pitfalls
Authors: Huang Cheng Cheng , Michael Claire W. 
Published: September 2012

AbstractWe report two cases of malignant deciduoid mesothelioma (MDM), a very rare variant of malignant mesothelioma (MM). Case 1: An 18‐year‐old male with no history of asbestos exposure presented with worsening abdominal pain, anorexia, and vomiting after a motor vehicle accident. A CT scan showed small amount of ascites and abdominal mass. An exploratory laparotomy revealed multiple yellow tan, firm nodules on the peritoneum and omentum. He received palliative treatment and died 5 months after the diagnosis. Case 2: A 64‐year‐old female with history of asbestos exposure initially presented with abdominal distension. CT scan showed abdominal mass with a large amount of ascites. A diagnostic laparoscopy revealed multiple peritoneal nodules. She underwent several regimens of chemotherapy over a period of 69 months and is still alive to date. In both cases, features of mesothelial origin were subtle and the smears showed predominantly single cells with marked nuclear atypia. The second case also contained few two‐dimensional loose cell clusters with scalloped or hobnail borders. The clusters often exhibited a pseudoacinar structure surrounding a globular extracellular material. Groups of three to four cells often formed doublets and triplets with cell‐to‐cell windows.Our results show that MDM may not present with the traditional cytological features described in MM and can manifest with more nuclear pleomorphism resulting in erroneous diagnosis. Recognition of the subtle mesothelial features along with the appropriate ancillary tests is essential for accurate diagnosis. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.
Solid pseudopapillary tumor of the pancreas: ‘Experiences’ and ‘Lessons’ at a tertiary‐care oncology center
Authors: Bal Munita Meenu , Deodhar Kedar , Shrikhande Shailesh , Shukla Parul , Arya Supreeta , Ramadwar Mukta 
Published: September 2012

AbstractSolid pseudopapillary tumor of the pancreas (SPT) is a rare and fascinating entity of elusive histogenesis and unpredictable biology. It has a peculiar proclivity to afflict young females and involve the pancreatic body‐tail region. Cytology diagnosis of these rare neoplasms remains a challenge. We analyzed the cytology features of all SPT cases diagnosed on fine needle aspiration cytology (FNAC) from 2003 to 2009 along with their histopathology slides. Nineteen consecutive cases were diagnosed as SPT on FNAC. Fifteen out of nineteen cases were confirmed as true SPT on histopathology. Amongst the true SPT, all except one occurred in females. Age ranged from 14 to 50 years. Pseudopapillae bearing stout branches terminating in bulbous tips and enclosing transgressing vessels, separated from a collar of tumor cells by a clear zone of myxohyaline coat were pathognomonic of SPT. Singly dispersed monomorphic tumor cells with bland chromatin formed the second diagnostic component of SPT. Nuclear grooves and hyaline globules were in addition helpful in segregating SPT from its close differentials. In four cases diagnosed as SPT on FNAC, histopathology revealed a different final diagnosis (one case each of paraganglioma, extragastrointestinal stromal tumor, metastatic papillary renal cell carcinoma and inflammatory myofibroblastic tumor). Conversely, one case of SPT had been erroneously diagnosed as neuroendocrine tumor on FNAC. Six cases (40%) developed metastasis; commonest site being liver. In conclusion, cytology in conjunction with clinico‐radiologic findings plays a key role in making a correct diagnosis. Awareness of unique cytomorphological features is important in distinguishing this tumor from its diverse mimics. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.