bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methanol Conversion into Dimethyl Ether on the Anatase TiO2(001) Surface
Authors: Xiong Feng , Yu Yan‐Yan , Wu Zongfang , Sun Guanghui , Ding Liangbing , Jin Yuekang , Gong Xue‐Qing , Huang Weixin 
Published: November 2015

AbstractExploring reactions of methanol on TiO2 surfaces is of great importance in both C1 chemistry and photocatalysis. Reported herein is a combined experimental and theoretical calculation study of methanol adsorption and reaction on a mineral anatase TiO2(001)‐(1×4) surface. The methanol‐to‐dimethyl ether (DME) reaction was unambiguously identified to occur by the dehydration coupling of methoxy species at the fourfold‐coordinated Ti4+ sites (Ti4c), and for the first time confirms the predicted higher reactivity of this facet compared to other reported TiO2 facets. Surface chemistry of methanol on the anatase TiO2(001)‐(1×4) surface is seldom affected by co‐chemisorbed water. These results not only greatly deepen the fundamental understanding of elementary surface reactions of methanol on TiO2 surfaces but also show that TiO2 with a high density of Ti4c sites is a potentially active and selective catalyst for the important methanol‐to‐DME reaction.
Production of Diethyl Terephthalate from Biomass‐Derived Muconic Acid
Authors: Lu Rui , Lu Fang , Chen Jiazhi , Yu Weiqiang , Huang Qianqian , Zhang Junjie , Xu Jie 
Published: November 2015

AbstractWe report a cascade synthetic route to directly obtain diethyl terephthalate, a replacement for terephthalic acid, from biomass‐derived muconic acid, ethanol, and ethylene. The process involves two steps: First, a substituted cyclohexene system is built through esterification and Diels–Alder reaction; then, a dehydrogenation reaction provides diethyl terephthalate. The key esterification reaction leads to improved solubility and modulates the electronic properties of muconic acid, thus promoting the Diels–Alder reaction with ethylene. With silicotungstic acid as the catalyst, nearly 100 % conversion of muconic acid was achieved, and the cycloadducts were formed with more than 99.0 % selectivity. The palladium‐catalyzed dehydrogenation reaction preferentially occurs under neutral or mildly basic conditions. The total yield of diethyl terephthalate reached 80.6 % based on the amount of muconic acid used in the two‐step synthetic process.
Regioselective, Asymmetric Formal Hydroamination of Unactivated Internal Alkenes
Authors: Xi Yumeng , Butcher Trevor W. , Zhang Jing , Hartwig John F. 
Published: November 2015

AbstractWe report the regioselective and enantioselective formal hydroamination of unsymmetrical internal alkenes catalyzed by a copper catalyst ligated by DTBM‐SEGPHOS. The regioselectivity of the reaction is controlled by the electronic effects of ether, ester, and sulfonamide groups in the homoallylic position. The observed selectivity underscores the influence of inductive effects of remote substituents on the selectivity of catalytic processes occurring at hydrocarbyl groups, and the method provides direct access to various 1,3‐aminoalcohol derivatives with high enantioselectivity.
Modular PROTAC Design for the Degradation of Oncogenic BCR‐ABL
Authors: Lai Ashton C. , Toure Momar , Hellerschmied Doris , Salami Jemilat , Jaime‐Figueroa Saul , Ko Eunhwa , Hines John , Crews Craig M. 
Published: November 2015

AbstractProteolysis Targeting Chimera (PROTAC) technology is a rapidly emerging alternative therapeutic strategy with the potential to address many of the challenges currently faced in modern drug development programs. PROTAC technology employs small molecules that recruit target proteins for ubiquitination and removal by the proteasome. The synthesis of PROTAC compounds that mediate the degradation of c‐ABL and BCR‐ABL by recruiting either Cereblon or Von Hippel Lindau E3 ligases is reported. During the course of their development, we discovered that the capacity of a PROTAC to induce degradation involves more than just target binding: the identity of the inhibitor warhead and the recruited E3 ligase largely determine the degradation profiles of the compounds; thus, as a starting point for PROTAC development, both the target ligand and the recruited E3 ligase should be varied to rapidly generate a PROTAC with the desired degradation profile.
Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends
Authors: Poulose Anesh Manjaly , Piccarolo Stefano , Carbone Domenico , Al‐Zahrani Saeed M. 
Published: November 2015

ABSTRACTTwo structurally different plasticizers (cyclic and linear) and the effect of cryogenic grinding on the solidification behavior at high cooling rates by a continuous cooling transformation approach of poly(butylene terephthalate)/poly(ethylene terephthalate), PBT/PET, blends are described. The solidification curve (density versus cooling rate) is confirmed as an effective tool to compare the differences in crystallization behavior under conditions mimicking processing. In comparison to the bulky cyclic plasticizer, the linear oligomeric one was found to have a more pronounced influence on the crystallization behavior. A 60/40 by weight PBT/PET blend shows a drop‐off of density at ∼50 K/s. In the plasticized sample, the long‐range crystalline order appears up to a cooling rate of ∼250K/s, making the blend comparable to pure PBT. Grinding the components before blending further improves crystallizability and synergy to the addition of the plasticizer. The results suggest the important role of local chain mobility in the solidification behavior at high cooling rates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43083.
Eggshell reinforced biocomposite—An advanced “green” alternative structural material
Authors: Tiimob Boniface Jabik , Jeelani Shaik , Rangari Vijaya Kumar 
Published: November 2015

ABSTRACTThe need for bio‐based polymers as substitutes to recalcitrant petroleum sourced plastics is ever growing, because of increase in demand globally. Eggshell nanopowder (ENP) prepared using mechanical attrition and ultrasound irradiation was used to infuse a bio‐based polymer [Super Sap 100/1000 epoxy (SSE)] for possible enhancement of its mechanical properties. The ENP, neat SSE and SSE/ENP composites were characterized using X‐ray Diffraction, Transmission Electron Microscopy (TEM), Energy dispersive spectroscopy (EDS), Scanning Electron Microscopy, Thermogravimetic Analysis (TGA), Dynamic Mechanical Analysis (DMA), Thermomechanical Analysis (TMA) and flexure analysis. TEM and EDS analysis showed evidence of ENP in the SSE matrix whiles DMA and TMA analysis revealed significant improvements (7–22%) in the storage moduli and (3–17%) in coefficient of thermal expansion (CTE) respectively. Also, major delay in 5% decomposition temperatures and increases in char yields were observed in TGA analysis. The flexure strength, modulus, and toughness significantly improved by 6–31%, 11–37%, and 10–36%, respectively. Microstructure of fractured surfaces showed deflected crack paths which contributed to improve toughness. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43124.
Thermal and gas permeation properties of copolymers derived from 3‐methacryloxypropyltris(trimethylsiloxy)silane and adamantyl group‐containing methacrylate derivatives
Authors: Ando Shota , Yoshida Akihiro , Nakagawa Masao , Nagai Kazukiyo 
Published: November 2015

ABSTRACTNovel copolymer membranes derived from three types of adamantyl group‐containing methacrylate derivatives and 3‐methacryloxypropyltris(trimethylsiloxy)silane (SiMA) were synthesized via free radical polymerization. The thermal and permeation properties of these copolymer membranes were investigated. Copolymer membranes with less than 11.9 mol % adamantane content exhibited good membrane forming abilities that are suitable for permeation measurement. The decomposition temperature of all copolymers increased up to approximately 40–80°C with increasing adamantane content compared with poly(SiMA). Moreover, the glass transition temperature (Tg) of all copolymers increased up to approximately 46–60°C with increasing adamantane content compared with the theoretical value, which was estimated from Fox equation. 1‐Adamantyl methacrylate copolymer had the highest fractional free volume among the three types of adamantly group‐containing methacrylate derivatives. The gas permeability coefficient of this copolymer increased by 22–45% with increasing adamantane content compared with that of poly(SiMA). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43129.
Desktop classification of inland wetlands for systematic conservation planning in data‐scarce countries: mapping wetland ecosystem types, disturbance indices and threatened species associations at country‐wide scale
Authors: van Deventer Heidi , Nel Jeanne , Mbona Namhla , Job Nancy , Ewart‐Smith Justine , Snaddon Kate , Maherry Ashton 
Published: November 2015

Abstract

Data sets on wetlands required for the representation of aquatic ecosystem biodiversity and systematic wetland conservation planning are typically not available or are inadequate, particularly at country‐wide scale, which hinders conservation planning. The improvement in hierarchical classification systems and increased availability of broad‐scale data sets offers new opportunities to overcome these limitations.
This study demonstrates replicable methods for classifying wetland ecosystem types and condition country‐wide using broad‐scale data sets in data‐scarce countries.
A country‐wide data set, compiled primarily using remote sensing techniques, was combined with regional and landscape‐setting data sets to reflect the ecological and geomorphic biodiversity of wetlands. Geographical Information Systems (GIS) were employed to model wetland types, disturbance indices and identify priority wetlands through threatened faunal species associations using existing data. Accuracy of the national data was assessed through a congruency with two local data sets.
Most of the 1 680 306 ha of inland wetlands were classified as Natural (80%), of which the majority were located on Valley Floors (68%). However, the national data were found only to represent 54% of wetlands mapped at a local scale, and comparison with local data showed inaccuracies in the types and condition classifications.
Problems regarding spatial data quality and scale are discussed and suggestions for improvement are provided. The desktop classification steps can be reproduced easily for other data‐scarce countries. Data sets on freshwater ecosystems can assist in raising awareness and influence policy at a national scale.
Copyright © 2015 John Wiley & Sons, Ltd.
Two new reversible naphthalimide‐based fluorescent chemosensors for Hg2+
Authors: Li Gongchun , Gao Guangqin , Cheng Junye , Chen Xiaopo , Zhao Yufen , Ye Yong 
Published: November 2015

AbstractNaphthalimide‐based fluorescent probes 1 and 2 were synthesized, and were designed to form probe–Hg complexes through Hg2+ ions coordinated to the amide group and imidazole group. They showed high sensitivity and were selective ‘naked‐eye’ chemosensors for Hg2+ in phosphate buffer. The fluorescence of compounds 1 and 2 could be quenched up to 90% by the addition of Hg2+. Reversible probes can detect Hg2+ ions over a wide pH range (7.0–10.0). Copyright © 2015 John Wiley & Sons, Ltd.
Teaching and learning of medical biochemistry according to clinical realities: A case study
Authors: Jabaut Joshua M. , Dudum Ramzi , Margulies Samantha L. , Mehta Akshita , Han Zhiyong 
Published: November 2015

AbstractTo foster medical students to become physicians who will be lifelong independent learners and critical thinkers with healthy skepticism and provide high‐quality patient care guided by the best evidence, teaching of evidence‐based medicine (EBM) has become an important component of medical education. Currently, the teaching and learning of biochemistry in medical schools incorporates its medical relevance and applications. However, to our knowledge there have been no reports on integrating EBM with teaching and learning medical biochemistry. Here, we present a case study to illustrate the significance of this approach. This case study was based on a biochemistry/nutrition question in a popular board review book about whether a homeless alcoholic man is at risk of developing a deficiency of vitamin E. The possible answers and explanation provided in the book raised a question about the correct answer, which provided us with an opportunity to adapt the philosophy and certain basic EBM principles to find evidence for the clinical applicability of a commonly taught biochemistry topic. The outcome of this case study not only taught us how to conduct an EBM exercise to answer a specific patient question, but also provided us with an opportunity for in‐depth teaching and learning of the medical relevance of a specific biochemistry topic based on the best clinical evidence obtained from a systematic research of medical literature. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:95–98, 2016.
Ceria‐Containing Ordered Mesoporous Silica: Synthesis, Properties, and Applications
Authors: Pal Nabanita , Cho Eun‐Bum , Patra Astam K. , Kim Dukjoon 
Published: November 2015

AbstractStructural architecture and unique physical, chemical, thermal, and mechanical properties of ordered mesoporous silica materials can be tuned. High flexibility of silica materials can provide good support for different metal nanoparticles, metal oxides, and organic functional groups. The properties of silica materials can vary to a great extent by introducing the optimum amount of metal species co‐doped, dispersed or composites with the silica mesostructure. The present study investigates the deposition of CeIII/IV/CeO2 on the silica surface by using different wet chemical engineering methods, illustrates the syntheses of those ceria–silica or metal doped ceria–silica nanomaterials and offers clear picture of the influence that incorporated ceria concentration has on the properties of the support material. Ceria–silica based ordered mesoporous materials can have numerous applications is also discussed in this article, emphasizing its use as a heterogeneous catalyst in particular.
Selectivity Studies Towards the Synthesis of Novel Biaryl Ureas by (Hetero)Nanocatalysis: Size Control and Support Effects
Authors: Senra Jaqueline D. , Viana Gil M. , Malta Luiz Fernando B. , Simas Alessandro B. C. , Aguiar Lucia C. S. 
Published: November 2015

AbstractA series of novel biaryl ureas containing different structural patterns have been prepared in good yields in the presence of palladium nanoparticles (PdNPs) with narrow particle size distribution. In particular, α, β‐, and γ‐hydroxypropylated cyclodextrins were used as reductants/stabilizers under different Pd‐to‐cyclodextrin ratios to tune the particle size and exploit the surface/cavity effects in the Suzuki–Miyaura reaction. Catalyst recovery in this process was pursued as well. Owing to its excellent performance, ceria was explored as a support for these PdNPs. The heterogeneous catalyst was characterized and investigated in the reaction of N‐(4‐iodo‐aryl),N′‐alkyl urea and phenylboronic acid. Our preliminary results revealed a high activity of the catalyst at 0.5 mol % Pd0 during three consecutive cycles. It is suggested that the specific interface between Pd0 and the high‐surface‐area ceria has a role in the catalytic performance.
Multiple Cycloaddition Reactions of Ketones with a β‐Diketiminate Al Compound
Authors: Sarish Sankaranarayana Pillai , Samuel Prinson P. , Roesky Herbert W. , Schulzke Carola , Nijesh Karikkeeriyil , De Susmita , Parameswaran Pattiyil 
Published: November 2015

AbstractA β‐diketiminate Al compound (1) with an exocyclic double bond reacts with two equivalents each of benzophenone and 2‐benzoylpyridine in a [4+2] cycloaddition to generate bicyclic and tricyclic compounds 2 and 3, respectively. Compound 2 consists of six‐ and eight‐membered aluminium rings, whereas 3 has two five‐ and one eight‐membered ring. Compounds 2 and 3 were characterized by a number of analytical tools including single‐crystal X‐ray diffraction. The quantum mechanical calculations suggest that the dissociation of the solvent molecule from 1 would lead to an active species 1A having two 1,4‐dipolar 4π electron moieties, in which the electrophilic site is the Al atom and the nucleophilic positions are polarized exocyclic and endocyclic CC π bonds. The detailed mechanistic study shows that the dipolarophiles, benzophenone, and 2‐benzoylpyridine undergo double cycloaddition with two 1,4‐dipolar 4π electron moieties of 1A. Herein, the addition of one molecule of the dipolarophile promotes the addition of the second one.
Multifunctional Tricarbazolo Triazolophane Macrocycles: One‐Pot Preparation, Anion Binding, and Hierarchical Self‐Organization of Multilayers
Authors: Lee Semin , Hirsch Brandon E. , Liu Yun , Dobscha James R. , Burke David W. , Tait Steven L. , Flood Amar H. 
Published: November 2015

AbstractProgramming the synthesis and self‐assembly of molecules is a compelling strategy for the bottom‐up fabrication of ordered materials. To this end, shape‐persistent macrocycles were designed with alternating carbazoles and triazoles to program a one‐pot synthesis and to bind large anions. The macrocycles bind anions that were once considered too weak to be coordinated, such as PF6−, with surprisingly high affinities (β2=1011 M−2 in 80:20 chloroform/methanol) and positive cooperativity, α=(4 K2/K1)=1200. We also discovered that the macrocycles assemble into ultrathin films of hierarchically ordered tubes on graphite surfaces. The remarkable surface‐templated self‐assembly properties, as was observed by using scanning tunneling microscopy, are attributed to the complementary pairing of alternating triazoles and carbazoles inscribed into both the co‐facial and edge‐sharing seams that exist between shape‐persistent macrocycles. The multilayer assembly is also consistent with the high degree of molecular self‐association observed in solution, with self‐association constants of K=300 000 M−1 (chloroform/methanol 80:20). Scanning tunneling microscopy data also showed that surface assemblies readily sequester iodide anions from solution, modulating their assembly. This multifunctional macrocycle provides a foundation for materials composed of hierarchically organized and nanotubular self‐assemblies.
Divergent Synthesis of Multisubstituted Tetrahydrofurans and Pyrrolidines via Intramolecular Aldol‐type Trapping of Onium Ylide Intermediates
Authors: Jing Changcheng , Xing Dong , Gao Lixin , Li Jia , Hu Wenhao 
Published: November 2015

AbstractThis paper reports a divergent strategy for the synthesis of multisubstituted tetrahydrofurans and pyrrolidines, starting from easily accessible β‐hydroxyketones or β‐aminoketones to react with diazo compounds. Under RhII catalysis, this transformation is proposed to proceed through a metal–carbene‐induced oxonium ylide or ammonium ylide formation followed by an intramolecular aldol‐type trapping of these active intermediates. A series of highly substituted tetrahydrofurans and pyrrolidines are synthesized in high yields with good to excellent diastereoselectivities. Preliminary biological evaluations revealed that both types of heterocycles show good PTP1B inhibitory activities.
Metal‐Free Allene‐Based Synthesis of Enantiopure Fused Polycyclic Sultones
Authors: Alcaide Benito , Almendros Pedro , Aragoncillo Cristina , Fernández Israel , Gómez‐Campillos Gonzalo 
Published: November 2015

AbstractThe controlled metal‐free preparation of fused δ‐sultone derivatives has been developed starting from hydroxyallenynes. The use of 2‐(3,3‐diethyltriaz‐1‐enyl)‐4‐methylbenzene‐1‐sulfonyl chloride in a sulfonylation/rearrangement sequence gives access to 1,3‐dien‐2‐yl arenesulfonates. These functionalized enynes suffered a direct cyclization/desaturation radical cascade, allowing the synthesis of a variety of enynyl [1,2]oxathiine 1,1‐dioxides. Stereoselective cyclization of the readily formed core through intramolecular Diels–Alder reaction has also been demonstrated, affording β‐lactam‐ and glucofuranoside‐fused δ‐sultone polycycles. These selective reactions have been studied experimentally and additionally, their reaction mechanisms have been investigated computationally by means of density functional theory calculations.
Semiparametric maximum likelihood estimation for a two‐sample density ratio model with right‐censored data
Authors: Wei Wenhua , Zhou Yong 
Published: November 2015

AbstractIn this paper we investigate a broader semiparametric two‐sample density ratio model based on two groups of right‐censored data. A semiparametric maximum likelihood estimator for the unknown finite and infinite dimensional parameters of the model is proposed and obtained by an EM algorithm. By using empirical process theory, we establish the uniform consistency and asymptotic normality of the proposed estimator. We moreover employ a Kolmogorov–Smirnov type test statistic to evaluate the model validity and a likelihood ratio test statistic to examine the treatment effects between the two groups. Simulation studies are conducted to assess the finite sample performance of the proposed estimator and to compare it with its alternatives. Finally a real data example is analyzed to illustrate its application.The Canadian Journal of Statistics44: 58–81; 2016 © 2015 Statistical Society of Canada
High‐Throughput Screening (HTS) by NMR Guided Identification of Novel Agents Targeting the Protein Docking Domain of YopH
Authors: Bottini Angel , Wu Bainan , Barile Elisa , De Surya K. , Leone Marilisa , Pellecchia Maurizio 
Published: November 2015

AbstractRecently we described a novel approach, named high‐throughput screening (HTS) by NMR that allows the identification, from large combinatorial peptide libraries, of potent and selective peptide mimetics against a given target. Here, we deployed the “HTS by NMR” approach for the design of novel peptoid sequences targeting the N‐terminal domain of Yersinia outer protein H (YopH‐NT), a bacterial toxin essential for the virulence of Yersinia pestis. We aimed at disrupting the protein–protein interactions between YopH‐NT and its cellular substrates, with the goal of inhibiting indirectly YopH enzymatic function. These studies resulted in a novel agent of sequence Ac‐F‐pY‐cPG‐d‐P‐NH2 (pY=phosphotyrosine; cPG=cyclopentyl glycine) with a Kd value against YopH‐NT of 310 nm. We demonstrated that such a pharmacological inhibitor of YopH‐NT results in the inhibition of the dephosphorylation by full‐length YopH of a cellular substrate. Hence, potentially this agent represents a valuable stepping stone for the development of novel therapeutics against Yersinia infections. The data reported further demonstrate the utility of the HTS by NMR approach in deriving novel peptide mimetics targeting protein–protein interactions.
Designing Irreversible Inhibitors—Worth the Effort?
Authors: González‐Bello Concepción 
Published: November 2015

AbstractDespite the unquestionable success of numerous irreversible drugs that are currently in clinical use, such as acetylsalicylic acid (Aspirin) and penicillin, the number of such approved drugs is much lower than that of noncovalent drugs. Over the years, the potential off‐target effects of these types of compounds have been the primary concern that has hampered their development. However, their remarkable advantages over noncovalent drugs and a better analysis of the risks have decreased the widespread skepticism surrounding them. The design of irreversible inhibitors is a challenge, particularly considering that in some cases their efficacy is due to complex and unexpected mechanisms of action. In this review the main advantages of irreversible inhibition are summarized, and the complexity of certain covalent modification mechanisms is highlighted with selected examples.