bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Investigation on the ClBcat‐Promoted Synthesis of Heterocyclic Boronic Esters
Authors: Jiang Julong , Zhang Zhenqi , Fu Yao 
Published: December 2016

AbstractA metal‐free oxyboration reaction, in which no acidic proton is involved and no intermediates bearing B−O σ‐bond were observed, was recently reported by the Blum group. Since it showed potential as a general strategy to synthesize heterocyclic boronic esters, understanding the mechanistic details is very important. Two possible pathways of this oxyboration reaction were examined. Moreover, three key processes were highlighted in the pathway, including borylative cyclization, chloride shift, and demethylation. According to the calculations, the early demethylation (which leads to a formal O−B bond) was found to be slightly exergonic, but to have an inaccessible barrier, whereas demethylation after the cyclization step was feasible. The rate‐determining step (RDS) was identified as the intramolecular cyclization for the oxyboration. Further theoretical investigation on the model reaction, in which an indole boronic ester is the product, revealed some interesting differences of reactivity between oxygen and nitrogen. Based on our calculation results, the N−C bond, which is usually treated as inert, can be cleaved in this case. Moreover, the there is a strong tendency for the RDS to shift from cyclization (as observed in the former oxyboration) to demethylation. Experiments were also conducted to confirm the calculations.
Keimvermitteltes Wachstum kolloidaler Metallnanokristalle
Authors: Xia Younan , Gilroy Kyle D. , Peng Hsin‐Chieh , Xia Xiaohu 
Published: December 2016

AbstractBeim keimvermittelten Wachstum handelt es sich um eine leistungsfähige und vielseitige Vorgehensweise zur Synthese kolloidaler Metallnanokristalle. Der große Reiz dieser Methode resultiert aus dem erstaunlichen Ausmaß an Kontrolle, das über die Größe, Form, Zusammensetzung und Struktur von Nanokristallen erzielt werden kann. Diese Parameter kontrollieren nicht nur die Eigenschaften von Nanokristallen, sondern entscheiden auch über deren Relevanz und Leistungsfähigkeit in diversen Anwendungen. Das keimvermittelte Wachstum bietet hervorragende Aussichten für die Erweiterung zahlreicher Anwendungen und öffnet zugleich Türen für neue Entwicklungen. Dieser Aufsatz veranschaulicht die schier endlos erweiterbare Diversität von Metallnanokristallen auf Basis von Keimen mit genau definierten und kontrollierbaren internen Strukturen in Verbindung mit einer geeigneten Kombination aus Bedeckungsmittel und Reduktionskinetik. Darüber hinaus werden neue Einsatzmöglichkeiten und zukünftige Richtungen aufgezeigt.
Orthogonal Cysteine Protection Enables Homogeneous Multi‐Drug Antibody–Drug Conjugates
Authors: Levengood Matthew R. , Zhang Xinqun , Hunter Joshua H. , Emmerton Kim K. , Miyamoto Jamie B. , Lewis Timothy S. , Senter Peter D. 
Published: December 2016

AbstractA strategy for the preparation of homogeneous antibody–drug conjugates (ADCs) containing multiple payloads has been developed. This approach utilizes sequential unmasking of cysteine residues with orthogonal protection to enable site‐specific conjugation of each drug. In addition, because the approach utilizes conjugation to native antibody cysteine residues, it is widely applicable and enables high drug loading for improved ADC potency. To highlight the benefits of ADC dual drug delivery, this strategy was applied to the preparation of ADCs containing two classes of auristatin drug‐linkers that have differing physiochemical properties and exert complementary anti‐cancer activities. Dual‐auristatin ADCs imparted activity in cell line and xenograft models that are refractory to ADCs comprised of the individual auristatin components. This work presents a facile method for construction of potent dual‐drug ADCs and demonstrates how delivery of multiple cytotoxic warheads can lead to improved ADC activities. Lastly, we anticipate that the conditions utilized herein for orthogonal cysteine unmasking are not restricted to ADCs and can be broadly utilized for site‐specific protein modification.
Widely Controllable Syngas Production by a Dye‐Sensitized TiO2 Hybrid System with ReI and CoIII Catalysts under Visible‐Light Irradiation
Authors: Lee Jong‐Su , Won Dong‐Il , Jung Won‐Jo , Son Ho‐Jin , Pac Chyongjin , Kang Sang Ook 
Published: December 2016

AbstractVisible‐light irradiation of a ternary hybrid catalyst prepared by grafting a dye, an H2 evolving CoIII catalyst and a CO‐producing ReI catalyst on TiO2 have been found to produce both H2 and CO (syngas) in CO2‐saturated N,N‐dimethyl formamide (DMF)/water solution containing a 0.1 m sacrificial electron donor. The H2/CO ratios are effectively controlled by changing either the water content of the solvent or the molar ratio of the ReI and CoIII catalysts ranging from 1:2 to 15:1. The controlled syngas formation is discussed in terms of competitive electron flow from TiO2 to each of the CO2‐reduction and hydrogen‐evolving sites depending on the efficiencies of the two catalytic reaction cycles under given reaction conditions.
Rhodium(I)‐Catalyzed Intermolecular Aza‐[4+3] Cycloaddition of Vinyl Aziridines and Dienes: Atom‐Economical Synthesis of Enantiomerically Enriched Functionalized Azepines
Authors: Zhu Chao‐Ze , Feng Jian‐Jun , Zhang Junliang 
Published: December 2016

AbstractA new synthetic application of vinyl aziridines as N‐containing three‐atom components in a rhodium‐catalyzed [4+3] cycloaddition reaction is described. The reaction proceeds well with various silyl dienol ethers and vinyl aziridines, and enables the efficient synthesis of highly functionalized azepines in an enantioselective manner with net inversion of absolute configuration. The salient features of the transformation include the use of readily available substrates, high selectivity, and mild reaction conditions, as well as the versatile functionalization of the products.
Hypervalent Iodine(III)‐Mediated Oxidative Fluorination of Alkylsilanes by Fluoride Ions
Authors: Xu Peng , Wang Feng , Fan Guilan , Xu Xiufang , Tang Pingping 
Published: December 2016

AbstractThe first example of a hypervalent iodine(III)‐mediated oxidative fluorination of alkylsilanes by fluoride ions without the use of transition metals is demonstrated. This reaction is operationally simple, scalable, and proceeds under mild reaction conditions. Mechanistic studies suggest the involvement of a single‐electron transfer resulting from the interaction of an organopentafluorosilicate and aryliodonium difluoride, which were generated in situ from the corresponding alkylsilane and iodosobenzene, respectively, in the presence of fluoride ions.
A UPLC/MS/MS method for determination of protosappanin B in rat plasma and its application of a pharmacokinetic and bioavailability study
Authors: Chen Wei‐Ying , Zhou Xian‐Zhen , Wu Li‐Lan , Wu Yun‐Shan , Wang Shu‐Mei , Liu Bo , Guo De‐An 
Published: December 2016

AbstractCaesalpinia sappan L. is a traditional medicinal plant which is used for promoting blood circulation and cerebral apoplexy therapy in China. Previous reports showed that the extracts of Caesalpinia sappan L. could exert vasorelaxant activity and anti‐inflammation activity. Protosappanin B is a major constituent of C. sappan L., and showed several important bioactivities. The separation was achieved by an Acquity UPLC BEH Symmetry Shield RP18 column (1.7 μm, 2.1 × 100 mm) column with the gradient mobile phase consisting of 5 mm ammonium acetate aqueous solution and acetonitrile. Detection was carried out by using negative‐ion electrospray tandem mass spectrometry via multiple reaction monitoring. Plasma samples were preprocessed by an extraction with ethyl acetate, and apigenin was used as internal standard. The current UPLC–MS/MS assay was validated for linearity, accuracy, intraday and interday precisions, stability, matrix effects and extraction recovery. After oral and intravenous administration, the main pharmacokinetic parameters were as follows: peak concentrations, 83.5 ± 46.2 and 1329.6 ± 343.6 ng/mL; areas under the concentration–time curve, 161.9 ± 69.7 and 264.9 ± 56.3 μg h/L; and half‐lives, 3.4 ± 0.9 and 0.3 ± 0.1 h, respectively. The absolute bioavailability in rats of protosappanin B was 12.2%. The method has been successfully applied to a pharmacokinetic and bioavailability study of protosappanin B in rats.
Aorto‐Ostial Lesions: Battling an Old Foe
Authors: Belardi Jorge A. , Albertal Mariano 
Published: December 2016

Key Points

Aorto‐ostial lesions (AOLs) entail several diagnostic and treatment challenges.
The Flash Ostial System enables flaring of the overhanging stent, optimizing stent deployment in AOLs.
Careful planning is essential to achieve optimal stent implantation and avoid early and late complications during the treatment of AOLs.
A helping hand: GuideLiner use to facilitate stent delivery
Authors: Brown Brian J. , Abbott J. Dawn 
Published: December 2016

Key Points

The GuideLiner catheter system is a tool that can be used to increase procedural success in complex percutaneous coronary intervention.
The safety profile of the device has improved with successive generations and with increased operator experience.
Methods to utilize the GuideLiner safely and effectively are described in this article.
Chryseobacterium indologenes, a possible emergent organism resistant to carbapenem antimicrobials after stem cell transplantation
Authors: Imataki Osamu , Uemura Makiko 
Published: December 2016

Key Clinical MessageA 64‐year‐old female was diagnosed with adult T‐cell leukemia/lymphoma. She then underwent an unrelated allogeneic bone marrow transplantation with a reduced‐intensity regimen. She achieved engraftment followed by HHV‐6 encephalopathy. This was complicated by Chryseobacterium indologenes pneumonia. Chryseobacterium indologenes is now a possible emergent organism resistant to carbapenem after transplantation.
Hematite Nanorod Electrodes Modified with Molybdenum: Photoelectrochemical Studies
Authors: Cots Ainhoa , Cibrev Dejan , Bonete Pedro , Gómez Roberto 
Published: December 2016

AbstractThe preparation of hematite nanorod electrodes modified with molybdenum and their photoelectrochemical behavior for water photooxidation have been addressed in the quest for improved electrodes for water splitting. The hematite nanorods were synthesized through chemical bath deposition, and Mo was added by following two variants of a drop‐casting method based on ammonium heptamolybdate solutions. FE‐SEM, TEM, XRD, and XPS were employed for electrode structural and morphological characterization. The reported results reveal that the impregnation method does not cause significant changes in the hematite structure and nanorod morphology. Importantly, the modification with Mo triggers a significant improvement in the photoactivity of the electrodes, obtaining a photocurrent increase of up to 43×. A specific Mott−Schottky analysis applicable to nanostructured electrodes was performed, revealing that the modification with Mo leads to an increase in electron concentration and to a shift of the flat band potential toward more positive values. A second role of Mo as a passivating agent needs to be invoked to explain the experimental observations. It is worth noting that this modification method allows precise control of the amount of Mo contained in the samples while maintaining the morphology of the electrode.
OFF‐ON‐OFF Red‐Emitting Fluorescent Indicators for a Narrow pH Window
Authors: Cidlina Antonin , Miletin Miroslav , Fathi‐Rasekh Mahtab , Nemykin Victor , Zimcik Petr , Novakova Veronika 
Published: December 2016

AbstractInvited for the cover of this issue are the groups of Victor Nemykin (University of Manitoba), and Petr Zimcik and Veronika Novakova (Charles University in Prague). The image depicts how tetrapyrazinoporphyrazines can be controlled by two switches. Read the full text of the article at 10.1002/chem.201604978.
Two‐Color Three‐State Luminescent Lanthanide Core–Shell Crystals
Authors: Balogh Cristina M. , Veyre Laurent , Pilet Guillaume , Charles Cyril , Viriot Laurent , Andraud Chantal , Thieuleux Chloé , Riobé François , Maury Olivier 
Published: December 2016

AbstractLuminescent core–shell crystals based on lanthanide tris‐dipicolinate complexes were obtained from the successive growing of two different lanthanide complex layers. Selective or simultaneous emission of each part of the crystal can be achieved by a careful choice of the excitation wavelength.
ascatNgs: Identifying Somatically Acquired Copy‐Number Alterations from Whole‐Genome Sequencing Data
Authors: Raine Keiran M. , Van Loo Peter , Wedge David C. , Jones David , Menzies Andrew , Butler Adam P. , Teague Jon W. , Tarpey Patrick , Nik‐Zainal Serena , Campbell Peter J. 
Published: December 2016

AbstractWe have developed ascatNgs to aid researchers in carrying out Allele‐Specific Copy number Analysis of Tumours (ASCAT). ASCAT is capable of detecting DNA copy number changes affecting a tumor genome when comparing to a matched normal sample. Additionally, the algorithm estimates the amount of tumor DNA in the sample, known as Aberrant Cell Fraction (ACF). ASCAT itself is an R‐package which requires the generation of many file types. Here, we present a suite of tools to help handle this for the user. Our code is available on our GitHub site (https://github.com/cancerit). This unit describes both ‘one‐shot’ execution and approaches more suitable for large‐scale compute farms. © 2016 by John Wiley & Sons, Inc.
Enriching s4U‐RNA Using Methane Thiosulfonate (MTS) Chemistry
Authors: Duffy Erin E. , Simon Matthew D. 
Published: December 2016

AbstractMetabolic labeling of cellular RNA is a useful approach to study RNA biology. 4‐Thiouridine (s4U) is a convenient nucleoside for metabolic labeling because it is cell permeable and is incorporated into newly transcribed RNA, and the sulfur moiety provides a handle for biochemical purification. However, a critical step in the purification of s4U‐RNA is the efficiency of the chemistry used to enrich s4U‐RNA. Here, we present a protocol for s4U‐RNA enrichment that includes efficient and reversible covalent chemistry to biotinylate s4U‐RNA using the activated disulfide methane thiosulfonate conjugated to biotin (MTS‐biotin), followed by enrichment on streptavidin beads. The efficiency of this chemistry reduces enrichment bias and requires less starting material, thereby expanding the utility of s4U to study RNA biology. © 2016 by John Wiley & Sons, Inc.
Biochemical, Biophysical and Cellular Techniques to Study the Guanine Nucleotide Exchange Factor, GIV/Girdin
Authors: Ghosh Pradipta , Aznar Nicolas , Swanson Lee , Lo I‐Chung , Lopez‐Sanchez Inmaculada , Ear Jason , Rohena Cristina , Kalogriopoulos Nicholas , Joosen Linda , Dunkel Ying , Sun Nina , Nguyen Peter , Bhandari Deepali 
Published: December 2016

AbstractCanonical signal transduction via heterotrimeric G proteins is spatiotemporally restricted, i.e., triggered exclusively at the plasma membrane, only by agonist activation of G protein‐coupled receptors via a finite process that is terminated within a few hundred milliseconds. Recently, a rapidly emerging paradigm has revealed a noncanonical pathway for activation of heterotrimeric G proteins via the nonreceptor guanidine‐nucleotide exchange factor, GIV/Girdin. Biochemical, biophysical, and functional studies evaluating this pathway have unraveled its unique properties and distinctive spatiotemporal features. As in the case of any new pathway/paradigm, these studies first required an in‐depth optimization of tools/techniques and protocols, governed by rationale and fundamentals unique to the pathway, and more specifically to the large multimodular GIV protein. Here we provide the most up‐to‐date overview of protocols that have generated most of what we know today about noncanonical G protein activation by GIV and its relevance in health and disease. © 2016 by John Wiley & Sons, Inc.
Organic Multilayer Films Studied by Scanning Tunneling Microscopy
Authors: He Yang , Kröger Jörg , Wang Yongfeng 
Published: December 2016

AbstractThis Minireview focuses exclusively on work with scanning tunneling microscopy to study the self‐assembled multilayer films (SAMTs) of organic molecules. The π‐conjugated organic molecules form different structures within different monolayers on various substrates. The interplay between molecule–substrate and intermolecular interactions plays a key role in determining the stacking mode of organic multilayer films. Different substrates strongly influence the organic‐film growth and electronic properties of the organic molecules. Geometric and electronic structures of SAMTs are important factors that may determine device performance. In addition to the inorganic interface, this Minireview addresses the organic–organic interface. Homo‐ and hetero‐SAMTs of organic molecules are also considered. The subtle interplay between structural and electronic characteristics, on one hand, and functionality and reactivity, on the other hand, are highlighted.
Pore Topology Effects in Positron Annihilation Spectroscopy of Zeolites
Authors: Zubiaga Asier , Warringham Robbie , Mitchell Sharon , Gerchow Lars , Cooke David , Crivelli Paolo , Pérez‐Ramírez Javier 
Published: December 2016

AbstractPositron annihilation spectroscopy (PAS) is a powerful method to study the size and connectivity of pores in zeolites. The lifetime of positronium within the host material is commonly described by the Tao‐Eldrup model. However, one of its largest limitations arises from the simple geometries considered for the shape of the pores, which cannot describe accurately the complex topologies in zeolites. Here, an atomic model that combines the Tao potential with the crystallographic structure is introduced to calculate the distribution and lifetime of Ps intrinsic to a given framework. A parametrization of the model is undertaken for a set of widely applied zeolite framework types (*BEA, FAU, FER, MFI, MOR, UTL), before extending the model to all known structures. The results are compared to structural and topological descriptors, and to the Tao–Eldrup model adapted for zeolites, demonstrating the intricate dependence of the lifetime on the pore architecture.
Detection of Receptor Heteromerization Using In Situ Proximity Ligation Assay
Authors: Gomes Ivone , Sierra Salvador , Devi Lakshmi A. 
Published: December 2016

AbstractAlthough G protein‐coupled receptor (GPCR) heteromerization has been extensively demonstrated in vitro using heterologous cells that overexpress epitope‐tagged receptors, their presence in endogenous systems is less well established. This is because a criterion to identify receptor heteromerization is the demonstration that the two interacting receptors are present not only in the same cell but also in the same subcellular compartment in close enough proximity to allow for direct receptor‐receptor interaction. This has been difficult to study in native tissues due to a lack of sensitive and selective tools not only capable of detecting low‐abundance proteins but also of demonstrating that they are in sufficiently close proximity to interact. The latter can be achieved using a proximity ligation assay (PLA). Detailed in this unit are protocols for demonstrating the presence of GPCR heteromers in endogenous cells as well as animal and human tissues, the controls required for these assays, and troubleshooting tips. © 2016 by John Wiley & Sons, Inc.
Stability of Drugs, Drug Candidates, and Metabolites in Blood and Plasma
Authors: Reed Gregory A. 
Published: December 2016

AbstractDetermination of drug or drug metabolite concentrations in biological samples, particularly in serum or plasma, is fundamental to describing the relationships between administered dose, route of administration, and time after dose for achieving the optimal clinical response. While a well‐characterized, accurate analytical method is needed to define these parameters, it must also be established that the analyte concentration in the sample at the time of analysis is identical to the concentration at sample acquisition. This is necessitated by the fact that drugs and their metabolites are susceptible to degradation in samples due to metabolism or to physical and chemical processes, resulting in a lower measured concentration than was in the original sample. Careful examination of analyte stability during processing and storage and, if necessary, adjustment of procedures and conditions to maximize stability, are a critical component of method validation to ensure the accuracy of the data. The protocols provided in this unit address the stability of the analytes in whole blood and blood‐derived samples prior to sample preparation for analysis. Issues addressed include sample acquisition, processing of whole blood, and storage of blood‐derived samples. © 2016 by John Wiley & Sons, Inc.
Electrochemical Water Oxidation by a Catalyst‐Modified Metal–Organic Framework Thin Film
Authors: Lin Shaoyang , Pineda‐Galvan Yuliana , Maza William A. , Epley Charity C. , Zhu Jie , Kessinger Matthew C. , Pushkar Yulia , Morris Amanda J. 
Published: December 2016

AbstractWater oxidation, a key component in artificial photosynthesis, requires high overpotentials and exhibits slow reaction kinetics that necessitates the use of stable and efficient heterogeneous water‐oxidation catalysts (WOCs). Here, we report the synthesis of UiO‐67 metal–organic framework (MOF) thin films doped with [Ru(tpy)(dcbpy)OH2]2+ (tpy=2,2′:6′,2′′‐terpyridine, dcbpy=5,5′‐dicarboxy‐2,2′‐bipyridine) on conducting surfaces and their propensity for electrochemical water oxidation. The electrocatalyst oxidized water with a turnover frequency (TOF) of (0.2±0.1) s−1 at 1.71 V versus the normal hydrogen electrode (NHE) in buffered solution (pH∼7) and exhibited structural and electrochemical stability. The electroactive sites were distributed throughout the MOF thin film on the basis of scan‐ratedependent voltammetry studies. This work demonstrates a promising way to immobilize large concentrations of electroactive WOCs into a highly robust MOF scaffold and paves the way for future photoelectrochemical water‐splitting systems.
Drought events and their effects on vegetation productivity in China
Authors: Zhang Li , Xiao Jingfeng , Zhou Yu , Zheng Yi , Li Jing , Xiao Han 
Published: December 2016

AbstractMany parts of the world have experienced frequent and severe droughts during the last few decades. Most previous studies examined the effects of specific drought events on vegetation productivity. In this study, we characterized the drought events in China from 1982 to 2012 and assessed their effects on vegetation productivity inferred from satellite data. We first assessed the occurrence, spatial extent, frequency, and severity of drought using the Palmer Drought Severity Index (PDSI). We then examined the impacts of droughts on China's terrestrial ecosystems using the Normalized Difference Vegetation Index (NDVI). During the period 1982–2012, China's land area (%) experiencing drought showed an insignificant trend. However, the drought conditions had been more severe over most regions in northern parts of China since the end of the 1990s, indicating that droughts hit these regions more frequently due to the drier climate. The severe droughts substantially reduced annual and seasonal NDVI. The magnitude and direction of the detrended NDVI under drought stress varied with season and vegetation type. The inconsistency between the regional means of PDSI and detrended NDVI could be attributed to different responses of vegetation to drought and the timing, duration, severity, and lag effects of droughts. The negative effects of droughts on vegetation productivity were partly offset by the enhancement of plant growth resulting from factors such as lower cloudiness, warming climate, and human activities (e.g., afforestation, improved agricultural management practices).