bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repurposing the Chemical Scaffold of the Anti‐Arthritic Drug Lobenzarit to Target Tryptophan Biosynthesis in Mycobacterium tuberculosis
Authors: Evans Genevieve L. , Gamage Swarna A. , Bulloch Esther M. M. , Baker Edward N. , Denny William A. , Lott J. Shaun 
Published: March 2014

AbstractThe emergence of extensively drug‐resistant strains of Mycobacterium tuberculosis (Mtb) highlights the need for new therapeutics to treat tuberculosis. We are attempting to fast‐track a targeted approach to drug design by generating analogues of a validated hit from molecular library screening that shares its chemical scaffold with a current therapeutic, the anti‐arthritic drug Lobenzarit (LBZ). Our target, anthranilate phosphoribosyltransferase (AnPRT), is an enzyme from the tryptophan biosynthetic pathway in Mtb. A bifurcated hydrogen bond was found to be a key feature of the LBZ‐like chemical scaffold and critical for enzyme inhibition. We have determined crystal structures of compounds in complex with the enzyme that indicate that the bifurcated hydrogen bond assists in orientating compounds in the correct conformation to interact with key residues in the substrate‐binding tunnel of Mtb‐AnPRT. Characterising the inhibitory potency of the hit and its analogues in different ways proved useful, due to the multiple substrates and substrate binding sites of this enzyme. Binding in a site other than the catalytic site was found to be associated with partial inhibition. An analogue, 2‐(2‐5‐methylcarboxyphenylamino)‐3‐methylbenzoic acid, that bound at the catalytic site and caused complete, rather than partial, inhibition of enzyme activity was found. Therefore, we designed and synthesised an extended version of the scaffold on the basis of this observation. The resultant compound, 2,6‐bis‐(2‐carboxyphenylamino)benzoate, is a 40‐fold more potent inhibitor of the enzyme than the original hit and provides direction for further structure‐based drug design.
A Native Chemical Ligation Handle that Enables the Synthesis of Advanced Activity‐Based Probes: Diubiquitin as a Case Study
Authors: Mulder Monique P. C. , El Oualid Farid , ter Beek Jarno , Ovaa Huib 
Published: March 2014

AbstractWe present the development of a native chemical ligation handle that also functions as a masked electrophile that can be liberated during synthesis when required. This handle can thus be used for the synthesis of complex activity‐based probes. We describe the use of this handle in the generation of linkage‐specific activity‐based deubiquitylating enzyme probes that contain substrate context and closely mimic the native ubiquitin isopeptide linkage. We have generated activity‐based probes based on all seven isopeptide‐linked diubiquitin topoisomers and demonstrated their structural integrity and ability to label DUBs in a linkage‐specific manner.
Coronary artery compression during intention to treat right ventricle outflow with percutaneous pulmonary valve implantation: Incidence, diagnosis, and outcome
Authors: Fraisse Alain , Assaidi Anass , Mauri Lucia , Malekzadeh‐Milani Sophie , Thambo Jean‐Benoit , Bonnet Damien , Iserin Laurence , Mancini Julien , Boudjemline Younes 
Published: March 2014

ObjectivesEvaluate the incidence, diagnosis, and outcome of coronary compression (CC) during right‐ventricular outflow tract interventions.BackgroundThe incidence, risk factors, diagnosis, and outcomes of CC during percutaneous pulmonary valve implantation are poorly defined.MethodsOne‐hundred consecutive patients (May 2008 to January 2012) undergoing transcatheter right‐ventricular outflow tract treatment in two institutions were studied.ResultsCC occurred in six patients (6%) with a right ventricular outflow conduit stenosis, at a median age of 24.5 (13–49) years. It involved the left main coronary artery in four and the right coronary artery originating from the left anterior descending coronary artery in two patients. Conduit types were homograft (n = 3), bioprosthesis (n = 2), and a pericardial patch (n = 1). Median diameter was 23 (17–24) mm at surgical implantation. CC was diagnosed through a selective coronary angiogram during balloon dilation of the conduit in the first three patients and through an aortic root angiogram for the three next cases because we recognized that proximal compression could be masked during coronary artery cannulation. It was suspected on pre‐procedure imaging (magnetic resonance imaging and/or computed tomography) in three cases. Patients with abnormal coronary anatomy tend to be at increased risk of CC (P = 0.0504). One institution had a higher incidence of CC (P = 0.04). CC resolved after balloon deflation. No patient underwent conduit stenting. Four patients underwent surgical reconstruction of right ventricular outflow tract.ConclusionsCC is accurately diagnosed during right‐ventricular outflow tract interventions. We recommend an aortic root angiogram during dilation with a non‐compliant balloon matching the diameter and length of the intended conduit implant. © 2014 Wiley Periodicals, Inc.
Microfluidic Hydrogenation Reactions by using a Channel‐Supported Rhodium Catalyst
Authors: Haywood Tom , Miller Philip W. 
Published: March 2014

AbstractA glass‐fabricated microfluidic device was used to screen a series of homogeneous alkene hydrogenation reactions by using Wilkinson’s catalyst. Good to excellent conversions were achieved for a range of alkene substrates within short reaction times (<2 min) and low hydrogen pressures (<0.2 MPa). During the course of the screening procedure, a metallic Rh layer was found to build up on the channels of the microfluidic device. Further investigation of this layer revealed that it was a highly active catalyst for the hydrogenation of alkenes, enones, and alkynes. Furthermore, this Rh layer catalyzed the hydrogenation of toluene to methylcyclohexane.
Titanium(salen)‐Catalysed Synthesis of Di‐ and Trithiocarbonates from Epoxides and Carbon Disulfide
Authors: Beattie Christopher , North Michael 
Published: March 2014

AbstractThe combination of a bimetallic titanium(salen) complex [Ti(salen)O]2 and either tetrabutylammonium bromide or tributylamine forms a highly active catalyst system for the reaction between epoxides and carbon disulfide to lead to di‐ and/or trithiocarbonates. Reactions can be performed at 90 °C by using just 0.5–1.0 mol % of the catalysts. The reactions proceed with the inversion of the epoxide configuration and on the basis of kinetic and spectroscopic evidence, a mechanism to account for the results is proposed.
Graphene Nanosheets and Quantum Dots: A Smart Material for Electrochemical Applications
Authors: Cincotto Fernando Henrique , Moraes Fernando Cruz , Machado Sergio Antonio Spinola 
Published: March 2014

AbstractA novel material for the electrochemical determination of endocrine disruptors using a composite based on graphene oxide modified with cadmium telluride quantum dots has been evaluated. The morphology, structure and electrochemical performance of the composite electrodes were characterised by transmission electron microscopy, dynamic light scattering, UV‐visible absorption spectra, fluorescence spectra, Raman spectra and cyclic voltammetry. The dynamic light scattering, transmission electronic microscopy and spectrophotometric measurements all showed good distribution of the quantum dots with a small particle size. The electrochemical measurements demonstrated the high performance of the composite response in the presence of a light source. Differential pulse voltammetry allowed the development of a method to determine 17β‐estradiol levels in the range from 0.2 to 4.0 μmol L−1 with a detection limit of 2.8 nmol L−1 (0.76 μg L−1).
Electrochemical Synthesis of Carbon Nanodots Directly from Alcohols
Authors: Deng Jianhui , Lu Qiujun , Mi Naxiu , Li Haitao , Liu Meiling , Xu Mancai , Tan Liang , Xie Qingji , Zhang Youyu , Yao Shouzhuo 
Published: March 2014

AbstractCarbon nanodots (C‐dots) show great potential as an important material for biochemical sensing, energy conversion, photocatalysis, and optoelectronics because of their water solubility, chemical inertness, low toxicity, and photo‐ and electronic properties. Numerous methods have been proposed for the preparation of C‐dots. However, complex procedures and strong acid treatments are often required, and the as‐prepared C‐dots tend to be of low quality, and in particular, have a low efficiency for photoluminescence. Herein, a facile and general strategy involving the electrochemical carbonization of low‐molecular‐weight alcohols is proposed. As precursors, the alcohols transited into carbon‐containing particles after electrochemical carbonization under basic conditions. The resultant C‐dots exhibit excellent excitation‐ and size‐dependent fluorescence without the need for complicated purification and passivation procedures. The sizes of the as‐prepared C‐dots can be adjusted by varying the applied potential. High‐quality C‐dots are prepared successfully from different small molecular alcohols, suggesting that this research provides a new, highly universal method for the preparation of fluorescent C‐dots. In addition, luminescence microscopy of the C‐dots is demonstrated in human cancer cells. The results indicate that the as‐prepared C‐dots have low toxicity and can be used in imaging applications.
The Energy Landscape of Uranyl–Peroxide Species
Authors: Tiferet Eitan , Gil Adrià , Bo Carles , Shvareva Tatiana , Nyman May , Navrotsky Alexandra 
Published: March 2014

AbstractInvited for the cover of this issue are the groups of Alex Navrotsky at University of California, Davis, Carles Bo at Institute of Chemical Research of Catalonia (ICIQ) and Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, and May Nyman at Oregon State University. The image depicts the stability of uranyl polyoxometalates changes as a function of the encapsulated species, which was quantified by experiment and theory. Read the full text of the article at 10.1002/chem.201304076.
Preparation of Immobilized L‐Prolinamide Via Enzymatic Polymerization of Phenolic L‐Prolinamide and Evaluation of Its Catalytic Performance for Direct Asymmetric Aldol Reaction
Authors: Qu Chengke , Zhao Wenshan , Zhang Lei , Cui Yuanchen 
Published: March 2014

ABSTRACTPhenolic L‐prolinamide was allowed to participate in enzymatic polymerization with horseradish peroxidase as the catalyst, generating immobilized L‐prolinamide. The catalytic performance of the resultant polymer‐supported L‐prolinamide for direct asymmetric aldol reaction between aromatic aldehyde and cyclohexanone was studied. The results show that as prepared L‐prolinamide can catalyze the aldol reaction at room temperature in the presence of H2O. Relevant aldol addition products are obtained with good yields (up to 91%), high diastereoselectivities (up to 6:94 dr), and medium enantioselectivities (up to 87% ee). Moreover, the title polymer‐supported catalyst can be recovered and reused for at least five cycles while the activity remains almost unchanged. Chirality 26:209–213, 2014. © 2014 Wiley Periodicals, Inc.
A Tripodal Trisilanol Ligand and Its Complexation Behavior towards CuI, CuII, and ZnII
Authors: Schax Fabian , Braun Beatrice , Limberg Christian 
Published: March 2014

AbstractA three‐step synthetic route for a new tripodal branched trisilanol ligand PhSi(OSiPh2OH)3 (LH3) was developed. X‐ray diffraction analysis revealed that the trisilanol crystallizes as a dimer with a cyclic hydrogen‐bonding network. The reaction of LH3 with three equivalents of CunMesn (Mes = mesityl) led to a hexanuclear compound [L2Cu6] (1), which was characterized by single‐crystal X‐ray diffraction analysis as well as by solution NMR spectroscopy. The crystal structure of 1 revealed that the compound features a hexagonal planar CuI6 ring, which is the first of its kind in an oxygen environment. Deprotonation of the ligand with n‐butyllithium and subsequent reaction with CuBr2 resulted in the dinuclear CuII complex [L′2Cu2][Li(THF2)]2 (2, THF = tetrahydrofuran), which contains a new siloxide ligand formed from L3– by the elimination of a SiOPh2 unit, as evidenced by X‐ray diffraction analysis. To check if the “Ph2SiO” elimination is a general behavior of this trisilanol, the reaction with ZnBr2 was investigated under analogous conditions. However, this led to the isolation of [L2Zn2][Li(OEt)]2 (3) without any rearrangement of the siloxide ligand.
Immobilization of lipase SMG1 and its application in synthesis of partial glycerides
Authors: Wang Weifei , Xu Yang , Qin Xiaoli , Lan Dongming , Yang Bo , Wang Yonghua 
Published: March 2014

Production and immobilization of lipase SMG1 and its application in catalyzing the esterification of oleic acid with glycerol were investigated. Resin D380 was screened to immobilize enzyme among five types of macroporous resins, and Fourier transform IR analysis proved the ionic bonds between functional group (NH2) and the amino acid residues in protein molecules. The immobilized lipase SMG1, with lipase/support ratio of 75 mg/g resin and pH 7.0, was used to catalyze the esterification, and high esterification degree of 68.37% was obtained under the conditions of the immobilized lipase at a concentration of 7.5% (w/w, with respect to total reactants), a fatty acid/glycerol molar ratio of 1:7, and 40°C. The immobilized lipase retained 49.7% of its initial activity after being used for six times. Compared with the free lipase SMG1, the immobilized one was discovered to exhibit higher temperature tolerance (40°C for the immobilized lipase SMG1 and 30°C for the free one) in the esterification of fatty acid and glycerol. The new finding on the improved operation temperature of the immobilized lipase SMG1 will push the enzyme's application in the oils and fats industry.Practical applications: The immobilized lipase SMG1‐catalyzed process for production of partial glycerides from glycerol and oleic acid described in this study provides several advantages over conventional methods including the absence of TAG product, the repeatable utilization of catalyst, and a high purity of DAG.Research on the immobilization of lipase SMG1, which is a novel mono‐ and diacylglycerol enzyme, has been firstly investigated. Compared with the free lipase, immobilized lipase SMG1 presented enhanced thermal stability in the esterification of glycerol with fatty acid. The new finding on the improved operation temperature of immobilized lipase SMG1 will push the enzyme's application in the oils and fats industry.
The effects of kinetic sorting on sediment mobility on steep slopes
Authors: Bacchi Vito , Recking Alain , Eckert Nicolas , Frey Philippe , Piton Guillaume , Naaim Mohamed 
Published: March 2014

ABSTRACTIn poorly mobile static armour, sorting is usually considered the result of hiding/exposure effects. We called this effect ‘static sorting’ in opposition to very efficient grain‐to‐grain mechanisms produced by a mobile mixture, called ‘kinetic sorting’. We hypothesized that kinetic sorting can be an important contributor to the morphodynamics of mountain streams and attempted to demonstrate this with new flume experiments.Two long runs were produced with natural poorly sorted sediments, and with transport stages of the coarse fraction (defined by the ratio between the shear stress and the critical shear stress for transport), smaller and higher than 1, respectively. Both runs produced an efficient transfer downstream of the injected material, but with a major difference: the first run (no kinetic sorting) produced permanent armour figuring clusters, akin to what has already been observed in similar experiments; the second run (with kinetic sorting) also produced bed armouring, but this armour was periodically totally destroyed, leading to substantial bed erosion.This phenomenon was explained by kinetic sorting, the effects of which are to produce an efficient downward migration of fine materials and bed surface armouring. The consequence is that fine materials are hidden to the flow during aggradation, allowing the slope to attain values much steeper than would have been expected at equilibrium for the mixture. However, whereas the surface armouring tends to stabilize the bed, construction of a layer of fine sediments at the subsurface also contributes to making it very unstable. These two contradictory effects explain the complex bed behaviours and the existence of very large bedload and slope fluctuations. Copyright © 2014 John Wiley & Sons, Ltd.
Prediction of the bioconcentration factor in common carp (Cyprinus carpio L.) using data from the dietary exposure bioaccumulation fish test
Authors: Hashizume Naoki , Tanabe Aiko , Inoue Yoshiyuki , Sawada Takashi , Murakami Hidekazu , Suzuki Yasuyuki , Sumi Shinichiro , Tsubokura Yasuhiro , Yoshida Tomohiko , Ajimi Shozo , Tsuji Toshiaki , Furukawa Kotaro 
Published: March 2014

Abstract

An approach to predicting the bioconcentration factor (BCFpre) from the predicted uptake rate constant (k1 pre) and the depuration rate constant measured in the dietary exposure bioaccumulation fish test (k2 dietary) [BCFpre = k1 pre/k2 dietary] is proposed in test guideline 305 of the Organization for Economic Cooperation and Development Guidelines for Testing of Chemicals. Data were collected on the BCFs of 197 test chemicals from Japan's Chemical Substances Control Law database. To demonstrate how the BCFpre compares with experimentally derived BCF under optimum conditions, 48 of 197 test chemicals, including a number of studies that could be considered problematic, were excluded from the analysis. The k1 pre was calculated by using 22 published prediction methods: the correlations between experimental uptake rate constants (k1 aqueous) and k1 pre for all prediction methods were very low and were statistically nonsignificant (p &gt; 0.05). Three prediction methods were also selected that gave relatively good values for the geometric mean of k1 pre/k1 aqueous and calculated values of BCFpre for 12 test chemicals. Linear relationships (p &lt; 0.05) are presented between logarithm of experimental and predicted BCF. The correlation coefficients of growth-corrected experimental and predicted BCF tended to be higher than values that were not growth corrected. For some test chemicals, use of predicted BCF led to a bioaccumulation classification different from that of existing regulatory criteria. Environ Toxicol Chem 2014;33:1406–1414. © 2014 SETAC
Rapid on-site separation of As(III) and As(V) in waters using a disposable thiol-modified sand cartridge
Authors: Du Jingjing , Che Dongsheng , Zhang Jianfeng , Jing Chuanyong 
Published: March 2014

Abstract

The rapid redox transformation of arsenic (As) species in waters presents a great environmental challenge in the accurate determination of its concentration and toxicity. The motivation of the present study was therefore to develop a method for rapid on-site separation of As(V) and As(III) in various aqueous matrices. The authors synthesized a thiol-modified sand (T-sand) that selectively removed As(III) but did not adsorb As(V). The novel application of this T-sand in a disposable cartridge was able to successfully separate As(V) (37–970 µg L−1) and As(III) (not detected to 488 µg L−1) in 23 groundwater samples collected in areas with naturally occurring As. The As speciation results determined with T-sand separation in the field were consistent with those obtained using high-performance liquid chromatography–atomic fluorescence spectrometry. Furthermore, the T-sand cartridge was applicable in a wide variety of matrices, including groundwater, leachants of the toxicity-characteristic leaching procedure, and extracts from the California waste extraction test; sequential extraction test; and in vitro gastrointestinal extraction. This easy-to-use separation method is especially suitable for routine field monitoring of As speciation. Environ Toxicol Chem 2014;33:1692–1696. © 2014 SETAC
Accuracy of administrative and clinical registry data in reporting postoperative complications after surgery for oral cavity squamous cell carcinoma
Authors: Awad Mahmoud I. , Shuman Andrew G. , Montero Pablo H. , Palmer Frank L. , Shah Jatin P. , Patel Snehal G. 
Published: March 2014

AbstractBackgroundThe purpose of this study was to describe and compare how postoperative complications after oral cavity squamous cell carcinoma (SCC) surgery are reported in medical records, institutional billing claims, and national clinical registries.MethodsThe medical records of 355 previously untreated patients who underwent surgery for oral cavity SCC at our institution were retrospectively reviewed for postoperative complications. Information was compared with claims and National Surgical Quality Improvement Program (NSQIP) data.ResultsWe identified 219 patients (62%) experiencing 544 complications (10% major). Billing claims identified 29% of these patients, 36% of overall complications, and 98% of major complications. Of overlapping patients, NSQIP identified 27% of patients, 33% of overall complications, and 100% of major complications noted on chart abstraction.ConclusionThe incidence of minor postoperative complications after oral cavity SCC surgery is relatively high. Both claims data and NSQIP accurately recorded major complications, but were suboptimal compared to chart abstraction in capturing minor complications. © 2014 Wiley Periodicals, Inc. Head Neck 37: 851–861, 2015
Postoperative concurrent chemotherapy and radiotherapy for high‐risk cutaneous squamous cell carcinoma of the head and neck
Authors: Tanvetyanon Tawee , Padhya Tapan , McCaffrey Judith , Kish Julie A. , Deconti Ronald C. , Trotti Andy , Rao Nikhil G. 
Published: March 2014

AbstractBackgroundDespite resection followed by adjuvant radiotherapy, high‐risk cutaneous squamous cell carcinomas of the head and neck region (SCCHN) often recur. Because adjuvant concurrent chemoradiation reduces recurrence among high‐risk mucosal SCCHN, we sought to understand its efficacy among high‐risk cutaneous SCCHN.MethodsWe conducted a retrospective cohort study of patients with cutaneous SCCHN who underwent adjuvant radiation or concurrent chemoradiation. Patients must have had stage III/IV with high‐risk features, including metastatic involvement of ≥2 lymph nodes, positive margins, or extracapsular invasion.ResultsThere were 61 patients: 27 (44%) received adjuvant radiation and 34 (56%) received adjuvant chemoradiation. The median recurrence‐free survivals were 15.4 and 40.3 months, respectively. Adjuvant chemoradiation significantly decreased the risk of recurrence or death in a multivariable analysis: hazard ratio (HR) 0.31 (p = .01). However, a difference in overall survival was not found.ConclusionFor high‐risk cutaneous SCCHN, adjuvant chemoradiation was associated with a better recurrence‐free survival than adjuvant radiation alone. © 2014 Wiley Periodicals, Inc. Head Neck 37: 840–845, 2015