bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiresponsive Polymer Assemblies Achieved by a Subtle Chain Terminal Modification
Authors: Liu Weiwei , Wang Yucai , Li Yang , Wang Feng , Yang Xianzhu , Sun Tianmeng , Du Jinzhi , Wang Jun 
Published: December 2013

AbstractInspired by the influence of chemical structure of end groups on the phase transition temperature of thermoresponsive polymers, we demonstrated a strategy to control the multi‐responsiveness of polymer assemblies via subtle modification of end groups of thermoresponsive polymer segments and revealed its potential application for drug delivery. By developing polymer assemblies composed of poly(aliphatic ester) as the inner core and thermoresponsive polyphosphoester as the outer shell, we showed that end groups of thermoresponsive polyphosphoester segments controlled the surface property of assemblies and further determined the stimuli‐responsive behavior. The phase‐transition temperatures of the unmodified polymer assemblies are tightly controlled by their surface properties due to the hydrophilic to hydrophobic transitions of end groups in response to an environmental stimulus (e.g. pH or light irradiation). External control over these surface properties can by asserted by adjusting the chemical structure and composition of the terminal groups of the thermoresponsive polyphosphoesters.
Synthesis of a Pillar[5]arene with Both Hydroxyl and Methoxycarbonyl‐Methoxy Groups and Its Host‐Guest Complexation with a Bis(imidazolium) Salt
Authors: Pan Mingguang , Xue Min 
Published: December 2013

AbstractBy the introduction of methoxycarbonyl‐methoxy groups and hydroxyl groups into a pillar structure, a pillararene entirely with two types of functional groups was successfully prepared, which can form a stable 1:1 complex with a bis(imidazolium) salt in CHCl3/acetone solution (V:V=1:1).
Fluorine NMR‐Based Screening on Cell Membrane Extracts
Authors: Veronesi Marina , Romeo Elisa , Lambruschini Chiara , Piomelli Daniele , Bandiera Tiziano , Scarpelli Rita , Garau Gianpiero , Dalvit Claudio 
Published: December 2013

AbstractThe possibility of measuring the action of inhibitors of specific enzymatic reactions in intact cells, cell lysates or membrane preparations represents a major advance in the lead discovery process. Despite the relevance of assaying in physiological conditions, only a small number of biophysical techniques, often requiring complex set‐up, are applicable to these sample types. Here, we demonstrate the first application of n‐fluorine atoms for biochemical screening (n‐FABS), a homogeneous and versatile assay based on 19F NMR spectroscopy, to the detection of high‐ and low‐affinity inhibitors of a membrane enzyme in cell extracts and determination of their IC50 values. Our approach can allow the discovery of novel binding fragments against targets known to be difficult to purify or where membrane‐association is required for activity. These results pave the way for future applications of the methodology to these relevant and complex biological systems.
Surface‐Modified TiO2 Photocatalysts Prepared by a Photosynthetic Route: Mechanism, Enhancement, and Limits
Authors: Neubert Susann , Ramakrishnan Ayyappan , Strunk Jennifer , Shi Haoyu , Mei Bastian , Wang Lidong , Bledowski Michal , Guschin Dmitrii A. , Kauer Max , Wang Yuemin , Muhler Martin , Beranek Radim 
Published: December 2013

AbstractSurface‐modified TiO2 photocatalysts were synthesized by a photosynthetic route involving visible‐light‐induced (λ>455 nm) activation of benzene and toluene at the surface of TiO2 leading to the formation of carbonaceous polymeric deposits. IR spectroscopic and photoelectrochemical experiments showed that the mechanism of the photosynthetic reactions involves intra‐bandgap surface states at TiO2 related to surface OH groups interacting with adsorbed aromatic molecules. The photosynthesized surface‐modified TiO2 materials exhibited enhanced activity, relative to pristine TiO2, in photocatalytic degradation (and complete mineralization) of 4‐chlorophenol. The improvement was pronounced particularly under visible‐light (λ>455 nm) irradiation with the relative initial photodegradation rate enhanced by a factor of four. The surface‐modified photocatalysts exhibited good stability under the operating conditions, and the optimum carbon content was approximately 0.5 wt %. Mechanistic studies showed that the enhanced visible‐light photodegradation of 4‐chlorophenol is due to modified surface‐adsorption properties that facilitate formation of a surface complex between titania and 4‐chlorophenol, rather than due to any sensitizing effect of the carbonaceous deposits. The study highlights the importance of considering the interaction between pollutant molecules and the photocatalyst surface in heterogeneous photocatalysis, and possibly opens up a route for photosynthesis of further surface‐modified photocatalysts with tuned surface properties.
Synthesis of Hybrid Cyclic Peptoids and Identification of Autophagy Enhancer
Authors: Rajasekhar Kolla , Narayanaswamy Nagarjun , Mishra Piyush , Suresh S. N. , Manjithaya Ravi , Govindaraju T. 
Published: December 2013

AbstractCyclic peptoids are potential candidates for diverse biological activities. However, applications of cyclic peptoids are limited by the synthetic difficulties, conformational flexibility of large cyclic peptoids, and lack of secondary amide in the backbone. Herein, an elegant methodology for the synthesis of small and medium‐size cyclic hybrid peptoids is developed. αN‐Alkyl and αN‐acyl substituents in N‐(2‐aminoethyl)glycine monomers enforce intra‐ and intermolecular cyclization to form stable six‐ and 12‐membered cyclic products, respectively. NMR studies show inter‐ and intramolecular hydrogen bonding in six‐ and 12‐membered cyclic peptoids, respectively. Screening of a cyclic peptoid library resulted in the identification of a potential candidate that enhanced autophagic degradation of cargo in a live cell model. Such upregulation of autophagy using small molecules is a promising approach for elimination of intracellular pathogens and neurodegenerative protein aggregates.
Nacrelike Nanocomposite Films from Fluorescent Hyperbranched Poly(amido amine)s and Clay Nanosheets
Authors: Hao Wentao , Ding Songyan , Zhang Liang , Liu Wei , Yang Wen 
Published: December 2013

AbstractInspired by the hierarchical structure of nacre, lots of functional nanocomposite films have been fabricated through finely tuning the composition and structure. To broaden their application in biological and biomedical research, it is highly demanded to develop a new strategy to fabricate nanocomposite films that are both biocompatible and functional. Herein, hyperbranched poly(amido amine)s (HPAMAMs) have been assembled with clay nanosheets. The obtained nanocomposite films show good mechanical performance and fluorescence properties. Analysis of the structure of the nanocomposite films indicates that the HPAMAMs and the clay nanosheets are stacked together in an orderly manner. The clay nanosheets align in the direction parallel to the film surface. Because of the inherent biocompatibility and autofluorescence property of the HPAMAMs, such composite films are thought to be very promising in applications requiring biocompatibility, fluorescence, and good mechanical performance. The method should provide a new route to the fabrication of functional nacrelike composite materials.
Access to Ultra‐High‐Molecular Weight Poly(ethylene) and Activity Boost in the Presence of Cyclopentene With Group 4 Bis‐Amido Complexes
Authors: Narayana Gurram Venkata , Xu Guangjuan , Wang Dongren , Frey Wolfgang , Buchmeiser Michael R. 
Published: December 2013

AbstractZrIV complexes of the type [Me2Si{(NR)(6‐{2‐(diethylboryl)phenyl}pyridyl‐2‐yl‐N)}ZrCl2⋅thf] (R=tBu (4), adamantyl (7 a); thf=tetrahydrofuran), [Me2Si{(NAd)(6‐{2‐(diphenylboryl)phenyl}pyridyl‐2‐yl‐N)}ZrCl2] (Ad=adamantyl (7 b)), the nonbridged half‐titanocene complexes of the type [(N‐{6‐(2‐diethylborylphenyl)pyrid‐2‐yl}‐NR)Cp′TiCl2] (R=Me, Cp′=C5H5 (12), Cp′=C5Me5 (13)), and the titanium(IV)‐based metallocene‐type complex [bis{N‐(6‐{2‐(diethylboryl)phenyl}pyrid‐2‐yl)NMe}TiCl2] (14) have been synthesized. The structures of complexes 7 b, 12, and 13 were determined by single‐crystal X‐ray diffraction analysis. In solution, complex 4 slowly rearranges to [Me2Si{(N‐tBu)(6‐{2‐(diethylboryl)phenyl}pyridyl‐2‐yl‐N)}2Zr] (4 a), the structure of which was unambiguously confirmed by single‐crystal X‐ray crystallography. Similarly, reaction of HfCl4 with Me2Si({RNLi}{6‐[2‐(diethylboryl)phenyl]pyridyl‐2‐ylNLi}) yielded the corresponding HfIV complexes [Me2Si{(NR)(6‐{2‐(diethylboryl)phenyl}pyridyl‐2‐ylN)}2Hf] (R=tBu (8) and Ad (9)). Upon activation of these complexes with methylalumoxane (MAO), complexes 4, 7 a, 7 b, and 12–14 showed activities up to 750 kg of polyethylene (PE)/molcat. bar h in the homopolymerization of ethylene (E), producing mainly linear PE (high‐density PE, HDPE) with molecular weights in the range of 1 800 000<Mn<4×106 g mol−1. In the copolymerization of E with cyclopentene (CPE), the polymerization activities of complexes 4, 7 a, and 7 b can be enhanced by a factor of 140 up to 7500 kg PE/molcat. bar h, which produced PE‐co‐poly(CPE) containing 3.5 mol % of CPE. This dramatic increase in polymerization activity for E in the presence of CPE can be attributed to an involvement of CPE in the polymerization process rather than to solvent polarity.
Gold Nanoparticles Embedded within Mesoporous Cobalt Oxide Enhance Electrochemical Oxygen Evolution
Authors: Lu Xunyu , Ng Yun Hau , Zhao Chuan 
Published: December 2013

AbstractGold nanoparticles incorporated in mesoporous cobalt oxides (Au/mCo3O4) are fabricated by a nanocasting method using porous silica as the hard template. The Au/mCo3O4 material exhibits enhanced catalytic activity towards water oxidation compared to bulk mCo3O4 in both alkaline and neutral solutions. The superior catalytic performance is ascribed to the synergistic effect of electronegative metal gold, which facilitates the generation of active CoIV sites, as well as the large specific surface area and the preferential exposure of catalytic active crystalline lattice.
Ecohydrology of the inland river basins in the Northwestern Arid Region of China
Authors: Shen Yanjun , Chen Yaning , Liu Changming , Smettem Keith 
Published: December 2013

ABSTRACTThe arid region in northwestern China covers 2·02 million square kilometres and is one of the most arid regions in the world. Positioned at the central part of the Eurasian Continent, this region experiences little influence from the Eastern and Southern Asian Monsoons and precipitation is formed mostly from westerly vapour. With a hyper arid climate, the annual precipitation in this region ranges from less than 20 mm at the oasis area to around 600 mm in the mountain regions, whereas potential evaporation can amount to 2000–3000 mm per annum. It is reported that strong evapotranspiration characterizes and dominates the water cycle in the arid basins. Nearly all the water resources of the oasis, where the human society exists, come from the mountain areas as river discharge from glacier/snow melting water, rainfall and subsurface flow from bedrock cracks. As a result, the hydrographs of the arid basins are affected by climate change via changes in precipitation partitioning (the ratio of rainfall and snowfall) and changes to seasonal distributions of precipitation and air temperature. These changes in turn directly affect the water yield and the vegetation response. Copyright © 2013 John Wiley & Sons, Ltd.
Groundwater depth and topography correlate with vegetation structure of an upland peat swamp, Budderoo Plateau, NSW, Australia
Authors: Hose Grant C. , Bailey Jane , Stumpp Christine , Fryirs Kirstie 
Published: December 2013

ABSTRACTSwamps, bogs and fens are diverse wetland ecosystems found worldwide. Within each region, different ecological processes and species dominate them, yet water levels and saturation of sediments appear key to the maintenance of vegetation and the ecosystem as a whole. Consequently, understanding how vegetation responds to water levels in these ecosystems is critical to their future management. This paper describes the floristic patterns observed in an upland swamp on the Budderoo Plateau, Southern Highlands, NSW, and relates the distribution of the vegetation communities to groundwater depth, soil type and site attributes. Three distinct vegetation assemblages were identified associated with (1) the main swamp axis, (2) the swamp margin and (3) the adjacent hillslopes. Elevation above the central swamp axis was the variable most strongly related to vegetation structure. Relative changes in elevation create a drainage gradient that allows higher elevation areas (hillslope and swamp marginal zones) to drain more readily than areas in the main swamp axis. Variation in vegetation was also related to median groundwater depth. Finally, soil organic matter content was a contributing factor with the swamp axis and marginal zones mostly having fibric, highly organic soils in contrast to the sandy, loamy soils on the hillslopes. Copyright © 2014 John Wiley & Sons, Ltd.
Ytterbium(III)‐Catalyzed Addition Reaction of Alkynyltrifluoroborate Salts to α‐Imino Esters: Efficient Synthesis of β‐Unsaturated α‐Amino Esters
Authors: Stefani Hélio A. , Manarin Flávia , Khan Amna N. , Vasconcelos Stanley N. S. 
Published: December 2013

AbstractWe describe the development of a mild and efficient method for the preparation of β‐unsaturated α‐amino esters through the ytterbium triflate catalyzed addition of potassium alkynyltrifluoroborate salts to imino esters. The synthetic viability of this protocol was supported by its high yields, short reaction times, and efficiency with regard to the scope of the substrates.
Ligand‐Free Copper‐Catalyzed One‐Pot Synthesis of Indole‐2‐carboxylic Esters
Authors: Zhu Zhiqiang , Yuan Jiangjun , Zhou Yirong , Qin Yang , Xu Jingshi , Peng Yiyuan 
Published: December 2013

AbstractA simple, efficient, and facile synthetic route for the preparation of indole‐2‐carboxylic esters was described. The cascade reactions of 2‐bromobenzaldehyde and glycine ester hydrochloride were promoted by Cu2O and a base to provide the corresponding products in good yields. Commercially available, inexpensive substrates and reagents were employed under mild reaction conditions in this one‐pot operation, which is complementary to existing methods for access to 2‐substituted indoles.
Cycloadducts of 1‐Alkyl‐1,2‐diphospholes with N‐Phenylmaleimide: Synthesis, Structure, Oxidation, and Thionation Reactions
Authors: Zagidullin Almaz , Miluykov Vasili , Sinyashin Oleg , Lönnecke Peter , Hey‐Hawkins Evamarie 
Published: December 2013

ABSTRACTThe [4+2] cycloaddition reaction of 1‐alkyl‐1,2‐diphospholes (1) with N‐phenylmaleimide proceeds at 25°С in toluene to give 1,7‐diphosphanorbornenes (2) as anti‐endo isomer only. Oxidation of 2 with air at room temperature or thionation with excess of sulfur at 80°С results in the formation of mixed valent PIII, PV 7‐oxo(thia)‐1,7‐diphosphanorbornenes (3, 4) in high yield. The polycyclic compounds 3 and 4 are air stable and have small sums of valence angles at the phosphorus atoms.
MEASURING THE DISPLACEMENT AND REPLACEMENT OF GOVERNMENT HEALTH EXPENDITURE
Authors: Dieleman Joseph L. , Hanlon Michael 
Published: December 2013

ABSTRACTResearch assessing the relationship between government health expenditure and development assistance for health channeled to governments (DAHG) has not considered that this relationship may depend on whether DAHG is increasing or decreasing. We explore this issue using general method of moments estimation and a panel of financial flows data spanning 119 countries and 16 years. Our primary concern is how DAHG affects government health expenditure as source (GHES). We disaggregate the average effect of DAHG and separately identify the effects of increases versus decreases in DAHG. We find that a $1 year‐over‐year increase in DAHG leads to a $0.62 (90% confidence interval (CI): 0.15, 1.09) decrease in GHES, whereas a $1 year‐over‐year decrease in DAHG does not have an effect on GHES that is statistically different from zero (CI: −0.67, 1.17). Simulation shows that the displacement of GHES between 1995 and 2010 reduced total government health expenditure by $152.8 billion (CI: 46.9, 277.6). Moreover, the irregular disbursement of DAHG reduced total government expenditure by $96.9 billion (CI: 0.5, 212.4). Thus, this research shows that health aid is fungible and highlights the cost of displacement and erratic aid disbursement. © 2013 The Authors. Health Economics published by John Wiley & Sons, Ltd.
Ergostane Steroids from Dysoxylum lukii
Authors: Hu Jiang , Song Yan , Shi Xiao‐Dong , Mao Xia , Chen Jian‐Gang , Zhu Lei 
Published: December 2013

AbstractPhytochemical investigation of the 70% EtOH extract from the stem bark of Dysoxylum lukii led to the isolation of three new ergostane steroids, (3β)‐3,20‐dihydroxyergosta‐5,24(28)‐dien‐7‐one (1), (3β,4β,7α)‐ergosta‐5,24(28)‐diene‐3,4,7‐triol (2), and (3β,7α)‐3,20‐dihydroxyergosta‐5,24(28)‐dien‐7‐yl acetate (3), together with the known compound (3β,4β)‐ergosta‐5,24(28)‐diene‐3,4,20‐triol (4). Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR (COSY, HMQC, HMBC, and NOESY) analyses.
Concise Stereoselective Total Synthesis of Leiocarpin C
Authors: Chandra Rao Dasireddi , Shekhar Vanam , Kumar Reddy Dorigondla , Chinnababu Baggu , Venkateswarlu Yenamandra 
Published: December 2013

AbstractA simple and highly concise strategy has been developed for the stereoselective total synthesis of leiocarpin C starting from commercially available mandelic ester. The strategy utilizes the OsO4‐catalyzed cis‐hydroxylation and selective reduction with K‐Selectride as key steps.
Ultrasound‐Assisted Synthesis of Highly Functionalized Cyclopentadienes via an Isocyanide‐Based Three‐Component Reaction
Authors: Emtiazi Hamideh , Ali Amrollahi Mohammad 
Published: December 2013

AbstractThis report provides a description of an efficient and simple procedure for the synthesis of substituted cyclopentadienes via a one‐pot three‐component reaction of cyclohexyl isocyanide, diethyl acetylenedicarboxylate and (arylmethylidene)malononitriles in H2O under ultrasonic irradiation. The remarkable advantages are the simplicity of the experimental procedures, high yields, short reaction times, and avoidance of organic solvents.
A Copper‐Catalyzed Multicomponent Reaction and ‘Click Strategy’ for the Stereoselective Synthesis of a New Series of Oxazolone Peptidomimetics withα‐Acylamino Amide andβ‐Amido Ketone Structures
Authors: Balan Biny , Bahulayan Damodaran 
Published: December 2013

AbstractA novel ‘click ligation’ strategy for the stereoselective synthesis of a medium‐size library of structurally complex and functionally diverse oxazolone peptidomimetics, which containα‐acylamino carboxamide orβ‐amido ketone residues, is presented. Most of these molecules have lipophilicity constant values (logP) in the qualifying range for cell permeability, and that indicates the possibilities of these new molecules to be used in the search for potential inhibitors for a broad spectrum of enzymes.
Stereoselective Synthesis of (Z)‐ and (E)‐Allyl Aryl Sulfides and Selenides from BaylisHillman Acetates under Neutral Conditions Using β‐Cyclodextrin in Water
Authors: Karnakar Konkala , Ramesh Katla , Narayana Murthy Sabbavarapu , Venkata Durga Nageswar Yadavalli 
Published: December 2013

AbstractThe first example of the stereoselective synthesis of (Z)‐ and (E)‐allyl aryl sulfides and selenides from BaylisHillman acetates under neutral conditions in H2O by supramolecular catalysis involving β‐cyclodextrin is reported. β‐Cyclodextrin can be recovered and reused. The reaction is very efficient in providing allyl aryl sulfides and selenides in good‐to‐excellent yields with clean reaction profiles under mild reaction conditions.
Synthesis of 5‐Aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles via Three‐Component Reaction of 1,1‐Bis(methylsulfanyl)‐2‐nitroethene, Aromatic Aldehydes, and Hydrazine
Authors: Alizadeh Abdolali , Reza Esmaili zand Hamid , Saberi Vahid , Mokhtari Javad 
Published: December 2013

AbstractAn efficient approach for the preparation of functionalized 5‐aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles 2 is described. This three‐component reaction between benzaldehydes 1, NH2NH2⋅H2O, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene proceeds in EtOH under reflux conditions in good‐to‐excellent yields. The structures of 2 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS). A plausible mechanism for this type of reaction is proposed (Scheme 2).
Alkaloids from Ochrosia borbonica
Authors: Zhang Bing‐Jie , Yan Ju‐Ming , Wu Zi‐Kun , Liu Ya‐Ping , Bao Mei‐Fen , Cheng Gui‐Guang , Luo Xiao‐Dong , Cai Xiang‐Hai , Li Yan 
Published: December 2013

AbstractTen new monoterpenoid indole alkaloids, ochroborines A and B (1 and 2, resp.), 10‐hydroxyisovallesiachotamine (3), 10‐hydroxyisositsirikine (4), 10,11‐dimethoxysitsirikine (5), 10‐methoxyapoyohimbine (6), 10‐hydroxyakuammidine (7), akuammidine 17‐O‐β‐D‐glucoside (8), 15α‐hydroxyapparicine (9), and 15α‐hydroxy‐10‐methoxyapparicine (10), and 24 known alkaloids were isolated from leaves and twigs of Ochrosia borbonica J. F.Gmel. These structures were elucidated based on 1D‐ and 2D‐NMR, FT‐IR, UV, and MS data. 10‐Hydroxyisovallesiachotamine (3), ellipticine, and 10‐methoxyellipticine showed cytotoxic activities against five human cancer cell lines.
Two New Trijugin‐Type Limonoids from Cipadessa cinerascens
Authors: Zhang Zhi‐Guo , Cheng Yun‐Tao , Hu Gui‐Lin , Li Guo‐Neng 
Published: December 2013

AbstractTwo new trijugin‐type limonoids, cipatrijugins G and H (1 and 2, resp.) along with four known limonoids, were isolated from the leaves of Cipadessa cinerascens. All structures were elucidated on the basis of spectroscopic analyses, including IR, 1D‐ and 2D‐NMR, and ESI‐MS and HR‐ESI‐MS techniques.
Two New Rosane‐Type Diterpenoids from Euphorbia ebracteolataHayata
Authors: Mu Shu‐Zhen , Jiang Chun‐Rong , Huang Tao , Hao Xiao‐Jiang 
Published: December 2013

AbstractTwo new diterpeniods, euphebracteolatins A and B (1 and 2, resp.) were isolated from Euphorbia ebracteolata Hayata, along with two known ones (3R)‐ent‐rosa‐1(10),15‐dien‐3α‐ol (3) and yuexiandajisu D (4). The structures were established by extensive spectroscopic analyses and comparison with literature data.
A Chiron Approach for the Total Synthesis of Crassalactone A
Authors: Singh Yadav Jhillu , Maheswara Rao Gokada , Thirupathaiah Bodakuntala 
Published: December 2013

AbstractThe total synthesis of crassalactone A (1) has been achieved in twelve steps starting from commercially available 1,5‐D‐gluconolactone. StillGennari olefination, one‐pot deprotection, and lactonization are the key reactions involved in the synthesis.
Synthesis of 4‐Arylisocoumarins (=4‐Aryl‐1H‐2‐benzopyran‐1‐ones) through Acidic Hydrolysis of (Z)‐2‐(1‐Aryl‐2‐methoxyethenyl)benzaldehydes, Followed by Oxidation
Authors: Kobayashi Kazuhiro , Miyatani Wataru , Kuroda Minami 
Published: December 2013

Abstract4‐Arylisocoumarins (=4‐aryl‐1H‐2‐benzopyran‐1‐ones) 6 were prepared from 2‐(1‐aryl‐2‐methoxyethenyl)‐1‐bromobenzenes 1. Successive treatment of these bromo styrenes with BuLi and 1‐formylpiperidine gave a mixture of (E)‐ and (Z)‐2‐(1‐aryl‐2‐methoxyethenyl)benzaldehydes 2. Hydrolysis of (Z)‐isomers with conc. HBr, followed by pyridinium chlorochromate (PCC) oxidation of the resulting 1H‐2‐benzopyran‐1‐ol derivatives 4 (and 5), afforded the desired products.