bluuebunny/crossref_metadata_2025 huggingface dataset:
Composition Engineering in Doctor‐Blading of Perovskite Solar Cells
Authors: Tang Shi , Deng Yehao , Zheng Xiaopeng , Bai Yang , Fang Yanjun , Dong Qingfeng , Wei Haotong , Huang Jinsong
Published: May 2017

Organic–inorganic halide perovskite (OIHP) solar cells with efficiency over 18% power conversion efficiency (PCE) have been widely achieved with lab scale spin‐coating method which is however not scalable for the fabrication of large area solar panels. The PCEs of OIHP solar cells made by scalable deposition methods, such as doctor‐blading or slot‐die coating, have been lagging far behind than spin‐coated devices. In this study the authors report composition engineering in doctor‐bladed OIHP solar cells with p–i–n planar heterojunction structure to enhance their efficiency. Phase purer OIHP thin films are obtained by incorporating a small amount of cesium (Cs+) and bromine (Br−) ions into perovskite precursor solution, which also reduces the required film formation temperature. Pinhole free OIHP thin films with micrometer‐sized grains have been obtained assisted by a secondary grain growth with added methylammonium chloride into the precursor solution. The OIHP solar cells using these bladed thin films achieved PCEs over 19.0%, with the best stabilized PCE reaching 19.3%. This represents a significant step toward scalable manufacture of OIHP solar cells.
All‐Manganese‐Based Binder‐Free Stretchable Lithium‐Ion Batteries
Authors: Gu Taoli , Cao Zeyuan , Wei Bingqing
Published: May 2017

Advanced electrode materials with bendability and stretchability are critical for the rapid development of fully flexible/stretchable lithium‐ion batteries. However, the sufficiently stretchable lithium‐ion battery is still underdeveloped that is one of the biggest challenges preventing from realizing fully deformable power sources. Here, a low‐temperature hydrothermal synthesis of a cathode material for stretchable lithium‐ion battery is reported by the in situ growth of LiMn2O4 (LMO) nanocrystals inside 3D carbon nanotube (CNT) film networks. The LMO/CNT film composite has demonstrated the chemical bonding between the LMO active materials and CNT scaffolds, which is the most important characteristic of the stretchable electrodes. When coupled with a wrinkled MnOx/CNT film anode, a binder‐free, all‐manganese‐based stretchable full battery cell is assembled which delivers a high average specific capacity of ≈97 mA h g−1 and stabilizes after over 300 cycles with an enormous strain of 100%. Furthermore, combining with other merits such as low cost, natural abundance, and environmentally friendly, the all‐manganese design is expected to accelerate the practical applications of stretchable lithium‐ion batteries for fully flexible and biomedical electronics.
Evaluation of a state based syndromic surveillance system for the classification and capture of non‐fatal occupational injuries and illnesses in New Jersey
Authors: Borjan Marija , Lumia Margaret
Published: May 2017

Background

This preliminary study evaluates a real‐time syndromic surveillance system to track occupationally‐related emergency room visits throughout New Jersey.

Methods

Emergency Department (ED) chief complaint fields were evaluated from 79 of 80 hospitals in NJ in 2014, using work‐related keywords and ICD‐9 E‐codes, to determine its ability to capture non‐fatal work‐related injuries. Sensitivity analysis and descriptive statistics, were used to evaluate and summarize the occupational injuries identified.

Results

Overall, 11 919 (0.3%) possible work‐related ED visits were identified from all ED visits. Events with the greatest number of ED visits were slips, trips, and falls (1679, 14%). Nature of injury included cuts, lacerations (1041, 9%). The part of the body most affected was the back (1414, 12%). This work‐related classifier achieved a sensitivity of 5.4%, a specificity of 99.8%, and a PPV of 2.8%.

Conclusions

This evaluation demonstrated that the syndromic surveillance reporting system can yield real‐time knowledge of work‐related injuries.
The effect of allergen immunotherapy in the onset of new sensitizations: a meta‐analysis
Authors: Di Lorenzo Gabriele , Leto‐Barone Maria Stefania , La Piana Simona , Plaia Antonella , Di Bona Danilo
Published: May 2017

Background

Although the preventive efficacy of allergen immunotherapy (AIT) in the onset of new allergen sensitizations has been asserted by many reviews, position papers, and consensus conferences, the evidence available is from only 3 studies. The objective of this work was a systematic review to evaluate the preventive efficacy of AIT in the onset of new allergen sensitizations. The end‐point was the risk difference (RD) in the onset of new allergen sensitizations between patients treated with AIT and pharmacotherapy.

Methods

Computerized bibliographic searches of MEDLINE, EMBASE, and the Cochrane Library (until November 30th, 2016) were done. Random‐effects and fixed‐effects model meta‐analyses were performed. Randomized controlled trials or observational studies comparing children treated with AIT with house dust mite (HDM) to subjects who did not receive AIT, with a long‐term observation period (at least 3 years including treatment and follow‐up) have been included.

Results

Eight studies totaling 721 children (390 treated with AIT and 331 with pharmacotherapy) met the inclusion criteria. The risk of bias was high. Low evidence supports the conclusion that AIT prevents the onset of new allergen sensitizations, with 3 of 8 studies reporting a reduction in the onset of new sensitizations in patients treated with AIT vs pharmacotherapy. Our meta‐analysis found no difference between AIT and pharmacotherapy, with high heterogeneity (RD, −0.10; 95% confidence interval [CI], −0.31 to 0.11; p = 0.32; I2 = 91.4%).

Conclusion

The data of this systematic review do not support a preventive effect in the onset of new allergen sensitizations, in children treated with AIT in comparison with those treated with pharmacotherapy.
Safety and Perioperative Adverse Events in Pediatric Endoscopic Sinus Surgery: An ACS‐NSQIP‐P Analysis
Authors: Roxbury Christopher R. , Li Lilun , Rhee Daniel , Jatana Kris R. , Shah Rahul K , Boss Emily F.
Published: May 2017

Introduction

This study describes safety outcomes of pediatric endoscopic sinus surgery (ESS) to identify risk factors for 30‐day postoperative adverse events using the National Surgical Quality Improvement Program–Pediatric (NSQIP‐P) database.

Methods

We performed a retrospective cohort study involving patients in the 2012–2015 NSQIP‐P database who underwent ESS. Predictors included demographics, comorbidities and surgical acuity. Outcomes included 30‐day complications, reoperations, and readmissions.

Results

Among 2,061 ESS cases identified, 1,829 (88.7%) were elective and 232 (11.3%) were urgent/emergent. There were 92 (4.5%) readmissions, 54 (2.6%) unplanned reoperations, and 61 (3.0%) complications. On multivariate analysis, readmission was associated with urgent/emergent procedures (OR 2.31, CI 1.36‐3.93, p<0.01) and history of bleeding disorder (OR 2.24, CI 1.12‐4.44, p = 0.02), reoperation was associated with urgent/emergent procedures (OR 5.78, CI 3.24‐10.34, p<0.01), and complications were associated with urgent/emergent procedures (OR 3.81, CI 2.13‐6.82, p<0.01) and history of bleeding disorder (OR 5.30, CI 2.74‐10.20, p<0.01). Bleeding requiring transfusion was associated with urgent/emergent procedures (OR 9.61, CI 2.90‐31.80, p<0.01), history of bleeding disorder (OR 14.16, CI 4.41‐45.45, p<0.01), and age <3 years (OR 3.92, CI 0.99‐15.61, p = 0.05). Black children were significantly more likely to undergo urgent/emergent surgery than white children (19.7% vs. 9.6%, p<0.01).

Conclusions

This multi‐institutional study confirms that while pediatric ESS is largely safe, urgent/emergent procedures carry the greatest risk of postoperative adverse events, and black children are significantly more likely to undergo higher acuity surgery than white children. Regardless of procedure acuity, young age and bleeding disorder are associated with higher risk of 30‐day adverse events.
Neuroimaging biomarkers and impaired olfaction in cognitively normal individuals
Authors: Vassilaki Maria , Christianson Teresa J. , Mielke Michelle M. , Geda Yonas E. , Kremers Walter K. , Machulda Mary M. , Knopman David S. , Petersen Ronald C. , Lowe Val J. , Jack Clifford R. , Roberts Rosebud O.
Published: May 2017

Objective

There is a need for inexpensive noninvasive tests to identify older healthy persons at risk for Alzheimer disease (AD) for enrollment in AD prevention trials. Our objective was to examine whether abnormalities in neuroimaging measures of amyloid and neurodegeneration are correlated with odor identification (OI) in the population‐based Mayo Clinic Study of Aging.

Methods

Cognitively normal (CN) participants had olfactory function assessed using the Brief Smell Identification Test (B‐SIT), underwent magnetic resonance imaging (n = 829) to assess a composite AD signature cortical thickness and hippocampal volume (HVa), and underwent 11C‐Pittsburgh compound B (n = 306) and 18fluorodeoxyglucose (n = 305) positron emission tomography scanning to assess amyloid accumulation and brain hypometabolism, respectively. The association of neuroimaging biomarkers with OI was examined using multinomial logistic regression and simple linear regression models adjusted for potential confounders.

Results

Among 829 CN participants (mean age = 79.2 years; 51.5% men), 248 (29.9%) were normosmic and 78 (9.4%) had anosmia (B‐SIT score < 6). Abnormal AD signature cortical thickness and reduced HVa were associated with decreased OI as a continuous measure (slope = −0.43, 95% confidence interval [CI] = −0.76 to −0.09, p = 0.01 and slope = −0.72, 95% CI = −1.15 to −0.28, p < 0.01, respectively). Reduced HVa, decreased AD signature cortical thickness, and increased amyloid accumulation were significantly associated with increased odds of anosmia.

Interpretation

Our findings suggest that OI may be a noninvasive, inexpensive marker for risk stratification, for identifying participants at the preclinical stage of AD who may be at risk for cognitive impairment and eligible for inclusion in AD prevention clinical trials. These cross‐sectional findings remain to be validated prospectively. Ann Neurol 2017;81:871–882
Chemische Struktur und Biosynthese der Crocagine, polycyclischer Peptide ribosomalen Ursprungs aus Chondromyces crocatus
Authors: Viehrig Konrad , Surup Frank , Volz Carsten , Herrmann Jennifer , Abou Fayad Antoine , Adam Sebastian , Köhnke Jesko , Trauner Dirk , Müller Rolf
Published: May 2017

Sekundärmetabolom‐Analysen in dem myxobakteriellen Naturstoffproduzenten Chondromyces crocatus Cm c5 führten zur Isolierung und Charakterisierung der Crocagine, neuartiger polycyclischer Peptide mit Tetrahydropyrrolo[2,3‐b]indol‐Grundgerüst. Der zugehörige Gencluster wurde durch eine Kombination aus gezielter Mutagenese und In‐vitro‐Experimenten zugeordnet. Auf Grundlage der Ergebnisse konnte ein Biosyntheseschema für die Crocagine erstellt werden. Diese Naturstoffe werden aus den drei C‐terminalen Aminosäuren eines Vorläuferpeptides gebildet und gehören daher zu einer neuen Klasse der ribosomal gebildeten und posttranslational modifizierten Peptide (RiPPs). Weiterhin konnte gezeigt werden, dass Crocagin A an das Regulatorprotein CsrA (“carbon storage regulator”) bindet, wodurch dessen Bindung an seine RNA‐Wechselwirkungspartner unterdrückt wird.
Inhibierung des humanen B12‐verarbeitenden Enzyms CblC durch Antivitamine B12 – Kristallstruktur des inaktiven ternären Komplexes mit dem Kosubstrat Glutathion
Authors: Ruetz Markus , Shanmuganathan Aranganathan , Gherasim Carmen , Karasik Agnes , Salchner Robert , Kieninger Christoph , Wurst Klaus , Banerjee Ruma , Koutmos Markos , Kräutler Bernhard
Published: May 2017

Antivitamine B12 gewinnen als robuste B12‐Dummys zunehmend biomedizinisches Interesse. Das potenzielle Antivitamin B12 2,4‐Difluorphenylethinylcobalamin (F2PhEtyCbl) wurde hergestellt, und seine 3D‐Struktur in Lösung und im Kristall wurde untersucht. Das chemisch inerte F2PhEtyCbl zeigte sich gegen Thermolyse seiner Co‐C‐Bindung bei 100 °C resistent, war stabil bei Bestrahlung mit (hellem) Tageslicht und blieb auch bei längerer Aufbewahrung in wässriger Lösung bei Raumtemperatur intakt. Es wurde vom humanen B12‐verarbeitenden Enzym CblC in Gegenwart des Kosubstrats Glutathion (GSH) mit hoher Affinität (KD=130 nm) gebunden. F2PhEtyCbl stabilisierte den ternären Komplex von CblC mit GSH und widerstand der Verarbeitung. Die Kristallstruktur dieses Komplexes lieferte erste Einblicke in die Wechselwirkungen eines Antivitamins B12 mit CblC sowie in die Anordnung von GSH und Base‐off‐Cobalamin im aktiven Zentrum dieses blockierten Enzyms.
Direct Nucleophilic Substitution Reaction of Cage B−H Bonds by Grignard Reagents: A Route to Regioselective B4‐Alkylation of o‐Carboranes
Authors: Tang Cen , Zhang Jiji , Xie Zuowei
Published: May 2017

Direct nucleophilic substitution reaction of cage B−H bonds of o‐carboranes by Grignard reagents in the absence of any transition metals has been achieved for the first time, and leads to the regioselective synthesis of a series of 4‐alkyl‐1,2‐diaryl‐o‐carboranes in very high yields. The presence of two electron‐withdrawing aryl groups on the cage carbon atoms is crucial to realizing the reaction. The regioselectivity is controlled by both electronic and steric factors. This work represents a new strategy for the development of methods for carborane functionalization.
Deprotonation of a Seemingly Hydridic Diborane(6) To Build a B−B Bond
Authors: Kaese Thomas , Budy Hendrik , Bolte Michael , Lerner Hans‐Wolfram , Wagner Matthias
Published: May 2017

Deprotonation of the doubly arylene‐bridged diborane(6) derivative 1H2 with (Me3Si)3CLi or (Me3Si)2NK gives the B−B σ‐bonded species M[1H] in essentially quantitative yields (THF, room temperature; M=Li, K, arylene=4,4′‐di‐tert‐butyl‐2,2′‐biphenylylene). With nBuLi as the base, the yield of Li[1H] drops to 20 % and the 1,1‐bis(9‐borafluorenyl)butane Li[2H] is formed as a side product (30 %). In addition to the 1,1‐butanediyl fragment, the two boron atoms of Li[2H] are linked by a μ‐H bridge. In the closely related molecule Li[3H], the corresponding μ‐H atom can be abstracted with (Me3Si)3CLi to afford the B−B‐bonded conjugated base Li2[3] (THF, 150 °C; 15 %). Li[1H] and Li[2H] were characterized by NMR spectroscopy and X‐ray crystallography.
A Structurally Characterized Fluoroalkyne
Authors: Hall Lewis M. , Tew David P. , Pridmore Natalie E. , Whitwood Adrian C. , Lynam Jason M. , Slattery John M.
Published: May 2017

The facile synthesis of a stable and isolable compound with a fluoroalkynyl group, M−C≡CF, is reported. Reaction of [Ru(C≡CH)(η5‐C5Me5)(dppe)] with an electrophilic fluorinating agent (NFSI) results in the formation of the fluorovinylidene complex [Ru(=C=CHF)(η5‐C5Me5)(dppe)][N(SO2Ph)2]. Subsequent deprotonation with LiN(SiMe3)2 affords the fluoroalkynyl complex [Ru(C≡CF)(η5‐C5Me5)(dppe)]. In marked contrast to the rare and highly reactive examples of fluoroalkynes that have been reported previously, this compound can be readily isolated and structurally characterized. This has allowed the structure and bonding in the CCF motif to be explored. Further electrophilic fluorination of this species yields the difluorovinylidene complex [Ru(C=CF2)(η5‐C5Me5)(dppe)][N(SO2Ph)2].
Morphologische Kontrolle von heteroleptischen cis‐ und trans‐Pd2L2L′2‐Käfigen
Authors: Bloch Witold M. , Holstein Julian J. , Hiller Wolf , Clever Guido H.
Published: May 2017

Die kontrollierte integrative Selbstsortierung metallosupramolekularer Strukturen eröffnet Möglichkeiten, mehr Komplexität und Funktion in eine einzelne selbstassemblierte Struktur einzuführen. Wir klären hier die Beziehung zwischen der Geometrie von drei Ligandkomponenten und der Morphologie von drei selbstsortierten heteroleptischen [Pd2L2L′2]4+‐Käfigen auf. So ergibt die Pd‐vermittelte Assemblierung von zwei doppelt‐einzähnigen Pyridyl‐Liganden mit einem nativen Bisswinkel von 75° und 120° einen cis‐[Pd2L2L′2]4+‐Käfig, wohingegen die gleiche Reaktion von zwei Liganden mit Bisswinkeln von 75° und 60° den letzteren Liganden in eine anti‐Konformation zwingt. Dies führt zu einem heteroleptischen trans‐[Pd2(anti‐L)2L′2]4+‐Käfig mit der Topologie einer “zweifach verbrückten Acht”. Jede der heteroleptischen Strukturen ist durch eine Käfig‐zu‐Käfig‐Umwandlung ihrer homoleptischen Vorstufen zugänglich. Die Morphologie der [Pd2L2L′2]‐Käfige kann durch selektiven Ligandenaustausch gezielt gesteuert werden.
A Membrane‐Free Neutral pH Formate Fuel Cell Enabled by a Selective Nickel Sulfide Oxygen Reduction Catalyst
Authors: Yan Bing , Concannon Nolan M. , Milshtein Jarrod D. , Brushett Fikile R. , Surendranath Yogesh
Published: May 2017

Polymer electrolyte membranes employed in contemporary fuel cells severely limit device design and restrict catalyst choice, but are essential for preventing short‐circuiting reactions at unselective anode and cathode catalysts. Herein, we report that nickel sulfide Ni3S2 is a highly selective catalyst for the oxygen reduction reaction in the presence of 1.0 m formate. We combine this selective cathode with a carbon‐supported palladium (Pd/C) anode to establish a membrane‐free, room‐temperature formate fuel cell that operates under benign neutral pH conditions. Proof‐of‐concept cells display open circuit voltages of approximately 0.7 V and peak power values greater than 1 mW cm−2, significantly outperforming the identical device employing an unselective platinum (Pt) cathode. The work establishes the power of selective catalysis to enable versatile membrane‐free fuel cells.
Selektive, narzisstische Selbstsortierung bei der Synthese von metallorganischen Strukturen mit Poly‐NHC‐Liganden
Authors: Sinha Narayan , Tan Tristan T. Y. , Peris Eduardo , Hahn F. Ekkehardt
Published: May 2017

Narzisstische Selbstsortierung wurde bei der Eintopfsynthese von drei metallorganischen molekularen Zylindern des Typs [M3{L‐(NHC)3}2](PF6)3 (M=Ag+, Au+; L=Benzol, Triphenylamin oder 1,3,5‐Triphenylbenzol) ausgehend von L‐(NHC)3 und Silber(I)‐ oder Gold(I)‐Ionen beobachtet. Die molekularen Zylinder enthalten stets nur einen Typ der Tris‐NHC‐Liganden, ohne dass Heteroligand‐Verbindungen zu detektieren sind. Die Transmetallierung der Tris‐NHC‐Liganden von Ag+ auf Au+ in einer Eintopfreaktion verläuft unter Erhaltung der supramolekularen Strukturen. Selbstsortierung wurde auch bei der Eintopfreaktion von Benzol‐verbrückten Tris‐ und Tetrakis‐NHC‐Liganden mit Ag2O beobachtet. Die vorliegende Studie überträgt erstmals narzisstische Selbstsortierung von Metall‐Ligand‐Wechselwirkungen in Werner‐Komplexen auf metallorganische Derivate.
Gold‐Catalyzed Cadiot–Chodkiewicz‐type Cross‐Coupling of Terminal Alkynes with Alkynyl Hypervalent Iodine Reagents: Highly Selective Synthesis of Unsymmetrical 1,3‐Diynes
Authors: Li Xiangdong , Xie Xin , Sun Ning , Liu Yuanhong
Published: May 2017

A new and efficient method for the synthesis of unsymmetrical 1,3‐butadiynes by gold‐catalyzed C(sp)–C(sp) cross‐coupling of terminal alkynes with alkynyl hypervalent iodine(III) reagents has been developed. The reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional‐group compatibility, and is a highly attractive complement to existing methods. Mechanistic studies reveal that formation of a phenanthrolinyl‐ligated gold(I) complex is crucial for the efficiency and selectivity of the target transformation.
Synthesis of Aldehydes by Organocatalytic Formylation Reactions of Boronic Acids with Glyoxylic Acid
Authors: Huang He , Yu Chenguang , Li Xiangmin , Zhang Yongqiang , Zhang Yueteng , Chen Xiaobei , Mariano Patrick S. , Xie Hexin , Wang Wei
Published: May 2017

Reported herein is a conceptually novel organocatalytic strategy for the formylation of boronic acids. New reactivity is engineered into the α‐amino‐acid‐forming Petasis reaction occurring between aryl boronic acids, amines, and glyoxylic acids to prepare aldehydes. The operational simplicity of the process and its ability to generate structurally diverse and valued aryl, heteroaryl, and α,β‐unsaturated aldehydes containing a wide array of functional groups, demonstrates the practical utility of the new synthetic strategy.
From Extended Nanofluidics to an Autonomous Solar‐Light‐Driven Micro Fuel‐Cell Device
Authors: Pihosh Yuriy , Uemura Jin , Turkevych Ivan , Mawatari Kazuma , Kazoe Yutaka , Smirnova Adelina , Kitamori Takehiko
Published: May 2017

Autonomous micro/nano mechanical, chemical, and biomedical sensors require persistent power sources scaled to their size. Realization of autonomous micro‐power sources is a challenging task, as it requires combination of wireless energy supply, conversion, storage, and delivery to the sensor. Herein, we realized a solar‐light‐driven power source that consists of a micro fuel cell (μFC) and a photocatalytic micro fuel generator (μFG) integrated on a single microfluidic chip. The μFG produces hydrogen by photocatalytic water splitting under solar light. The hydrogen fuel is then consumed by the μFC to generate electricity. Importantly, the by‐product water returns back to the photocatalytic μFG via recirculation loop without losses. Both devices rely on novel phenomena in extended‐nano‐fluidic channels that ensure ultra‐fast proton transport. As a proof of concept, we demonstrate that μFG/μFC source achieves remarkable energy density of ca. 17.2 mWh cm−2 at room temperature.
Biocatalytic Friedel–Crafts Acylation and Fries Reaction
Authors: Schmidt Nina G. , Pavkov‐Keller Tea , Richter Nina , Wiltschi Birgit , Gruber Karl , Kroutil Wolfgang
Published: May 2017

The Friedel–Crafts acylation is commonly used for the synthesis of aryl ketones, and a biocatalytic version, which may benefit from the chemo‐ and regioselectivity of enzymes, has not yet been introduced. Described here is a bacterial acyltransferase which can catalyze Friedel–Crafts C‐acylation of phenolic substrates in buffer without the need of CoA‐activated reagents. Conversions reach up to >99 %, and various C‐ or O‐acyl donors, such as DAPG or isopropenyl acetate, are accepted by this enzyme. Furthermore the enzyme enables a Fries rearrangement‐like reaction of resorcinol derivatives. These findings open an avenue for the development of alternative and selective C−C bond formation methods.
A Modular Flow Design for the meta‐Selective C−H Arylation of Anilines
Authors: Gemoets Hannes P. L. , Laudadio Gabriele , Verstraete Kirsten , Hessel Volker , Noël Timothy
Published: May 2017

Described herein is an effective and practical modular flow design for the meta‐selective C−H arylation of anilines. The design consists of four continuous‐flow modules (i.e., diaryliodonium salt synthesis, meta‐selective C−H arylation, inline copper extraction, and aniline deprotection) which can be operated either individually or consecutively to provide direct access to meta‐arylated anilines. With a total residence time of 1 hour, the desired product could be obtained in high yield and excellent purity without the need for column chromatography, and the residual copper content meets the standards for parenterally administered pharmaceutical substances.
Absolute Minimal Sampling of Homonuclear 2D NMR TOCSY Spectra for High‐Throughput Applications of Complex Mixtures
Authors: Hansen Alexandar L. , Li Dawei , Wang Cheng , Brüschweiler Rafael
Published: May 2017

Modern applications of 2D NMR spectroscopy to diagnostic screening, metabolomics, quality control, and other high‐throughput applications are often limited by the time‐consuming sampling requirements along the indirect time domain t1. 2D total correlation spectroscopy (TOCSY) provides unique spin connectivity information for the analysis of a large number of compounds in complex mixtures, but standard methods typically require >100 t1 increments for an accurate spectral reconstruction, rendering these experiments ineffective for high‐throughput applications. For a complex metabolite mixture it is demonstrated that absolute minimal sampling (AMS), based on direct fitting of resonance frequencies and amplitudes in the time domain, yields an accurate spectral reconstruction of TOCSY spectra using as few as 16 t1 points. This permits the rapid collection of homonuclear 2D NMR experiments at high resolution with measurement times that previously were only the realm of 1D experiments.
Phenotypic Identification of a Novel Autophagy Inhibitor Chemotype Targeting Lipid Kinase VPS34
Authors: Robke Lucas , Laraia Luca , Carnero Corrales Marjorie A. , Konstantinidis Georgios , Muroi Makoto , Richters André , Winzker Michael , Engbring Tobias , Tomassi Stefano , Watanabe Nobumoto , Osada Hiroyuki , Rauh Daniel , Waldmann Herbert , Wu Yao‐Wen , Engel Julian
Published: May 2017

Autophagy is a critical regulator of cellular homeostasis and metabolism. Interference with this process is considered a new approach for the treatment of disease, in particular cancer and neurological disorders. Therefore, novel small‐molecule autophagy modulators are in high demand. We describe the discovery of autophinib, a potent autophagy inhibitor with a novel chemotype. Autophinib was identified by means of a phenotypic assay monitoring the formation of autophagy‐induced puncta, indicating accumulation of the lipidated cytosolic protein LC3 on the autophagosomal membrane. Target identification and validation revealed that autophinib inhibits autophagy induced by starvation or rapamycin by targeting the lipid kinase VPS34.
Frozen Acrylamide Gels as Dynamic Nuclear Polarization Matrices
Authors: Viger‐Gravel Jasmine , Berruyer Pierrick , Gajan David , Basset Jean‐Marie , Lesage Anne , Tordo Paul , Ouari Olivier , Emsley Lyndon
Published: May 2017

Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain113Cd spectra from CdTe‐COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium‐rich surface.
Modified Tetrathiafulvalene as an Organic Conductor for Improving Performances of Li−O2 Batteries
Authors: Zhang Jinqiang , Sun Bing , Zhao Yufei , Kretschmer Katja , Wang Guoxiu
Published: May 2017

Large over‐potentials owing to the sluggish kinetics of battery reactions have always been the drawbacks of Li−O2 batteries, which lead to short cycle life. Although redox mediators have been intensively investigated to overcome this issue, side‐reactions are generally induced by the solvated nature of redox mediators. Herein, we report an alternative method to achieve more efficient utilization of tetrathiafulvalene (TTF) in Li−O2 batteries. By coordinating TTF+ with LiCl during charging, an organic conductor TTF+Clx− precipitate covers Li2O2 to provide an additional electron‐transfer pathway on the surface, which can significantly reduce the charge over‐potential, improve the energy efficiency of Li−O2 batteries, and eliminate side‐reactions between the lithium metal anode and TTF+. When a porous graphene electrode is used, the Li−O2 battery combined with TTF and LiCl shows an outstanding performance and prolonged cycle life.
Rhodium‐Catalyzed Enantioselective Radical Addition of CX4 Reagents to Olefins
Authors: Chen Bo , Fang Cheng , Liu Peng , Ready Joseph M.
Published: May 2017

We describe the synthetically useful enantioselective addition of Br−CX3 (X=Cl or Br) to terminal olefins to introduce a trihalomethyl group and generate optically active secondary bromides. Computational and experimental evidence supports an asymmetric atom‐transfer radical addition (ATRA) mechanism in which the stereodetermining step involves outer‐sphere bromine abstraction from a [(bisphosphine)RhIIBrCl] complex by a benzylic radical intermediate. This mechanism appears unprecedented in asymmetric catalysis.
Eight‐Electron Silver and Mixed Gold/Silver Nanoclusters Stabilized by Selenium Donor Ligands
Authors: Chang Wan‐Ting , Lee Po‐Yi , Liao Jian‐Hong , Chakrahari Kiran Kumarvarma , Kahlal Samia , Liu Yu‐Chiao , Chiang Ming‐Hsi , Saillard Jean‐Yves , Liu C. W.
Published: May 2017

The first atomically and structurally precise silver‐nanoclusters stabilized by Se‐donor ligands, [Ag20{Se2P(OiPr)2}12] (3) and [Ag21{Se2P(OEt)2}12]+(4), were isolated by ligand replacement reaction of [Ag20{S2P(OiPr)2}12] (1) and [Ag21{S2P(OiPr)2}12]+ (2), respectively. Furthermore, doping reactions of 4 with Au(PPh3)Cl resulted in the formation of [AuAg20{Se2P(OEt)2}12]+ (5). Structures of 3, 4, and 5 were determined by single‐crystal X‐ray diffraction. The anatomy of cluster 3 with an Ag20 core having C3 symmetry is very similar to that of its dithiophosphate analogue 1. Clusters 4 and 5 exhibit an Ag21 and Au@Ag20 core of Oh symmetry composed of eight silver capping atoms in a cubic arrangement and encapsulating an Ag13 and Au@Ag12 centered icosahedron, respectively. Both ligand exchange and heteroatom doping result in significant changes in optical and emissive properties for chalcogen‐passivated silver nanoparticles, which have been theoretically confirmed as 8‐electron superatoms.
Antivitamin B12 Inhibition of the Human B12‐Processing Enzyme CblC: Crystal Structure of an Inactive Ternary Complex with Glutathione as the Cosubstrate
Authors: Ruetz Markus , Shanmuganathan Aranganathan , Gherasim Carmen , Karasik Agnes , Salchner Robert , Kieninger Christoph , Wurst Klaus , Banerjee Ruma , Koutmos Markos , Kräutler Bernhard
Published: May 2017

B12 antivitamins are important and robust tools for investigating the biological roles of vitamin B12. Here, the potential antivitamin B12 2,4‐difluorophenylethynylcobalamin (F2PhEtyCbl) was prepared, and its 3D structure was studied in solution and in the crystal. Chemically inert F2PhEtyCbl resisted thermolysis of its Co−C bond at 100 °C, was stable in bright daylight, and also remained intact upon prolonged storage in aqueous solution at room temperature. It binds to the human B12‐processing enzyme CblC with high affinity (KD=130 nm) in the presence of the cosubstrate glutathione (GSH). F2PhEtyCbl withstood tailoring by CblC, and it also stabilized the ternary complex with GSH. The crystal structure of this inactivated assembly provides first insight into the binding interactions between an antivitamin B12 and CblC, as well as into the organization of GSH and a base‐off cobalamin in the active site of this enzyme.
Observation of CH⋅⋅⋅π Interactions between Methyl and Carbonyl Groups in Proteins
Authors: Perras Frédéric A. , Marion Dominique , Boisbouvier Jérôme , Bryce David L. , Plevin Michael J.
Published: May 2017

Protein structure and function is dependent on myriad noncovalent interactions. Direct detection and characterization of these weak interactions in large biomolecules, such as proteins, is experimentally challenging. Herein, we report the first observation and measurement of long‐range “through‐space” scalar couplings between methyl and backbone carbonyl groups in proteins. These J couplings are indicative of the presence of noncovalent C−H⋅⋅⋅π hydrogen‐bond‐like interactions involving the amide π network. Experimentally detected scalar couplings were corroborated by a natural bond orbital analysis, which revealed the orbital nature of the interaction and the origins of the through‐space J couplings. The experimental observation of this type of CH⋅⋅⋅π interaction adds a new dimension to the study of protein structure, function, and dynamics by NMR spectroscopy.
High‐Fidelity, Narcissistic Self‐Sorting in the Synthesis of Organometallic Assemblies from Poly‐NHC Ligands
Authors: Sinha Narayan , Tan Tristan T. Y. , Peris Eduardo , Hahn F. Ekkehardt
Published: May 2017

Highly selective, narcissistic self‐sorting has been observed in the one‐pot synthesis of three organometallic molecular cylinders of type [M3{L‐(NHC)3}2](PF6)3 (M=Ag+, Au+; L=1,3,5‐benzene, triphenylamine, or 1,3,5‐triphenylbenzene) from L‐(NHC)3 and silver(I) or gold(I) ions. The molecular cylinders contain only one type of tris‐NHC ligand with no crossover products detectable. Transmetalation of the tris‐NHC ligands from Ag+ to Au+ in a one‐pot reaction with retention of the supramolecular structures is also demonstrated. High‐fidelity self‐sorting was also observed in the one‐pot reaction of benzene‐bridged tris‐NHC and tetrakis‐NHC ligands with Ag2O. This study for the first time extends narcissistic self‐sorting in metal–ligand interactions from Werner‐type complexes to organometallic derivatives.
Base‐Selective Five‐ versus Six‐Membered Ring Annulation in Palladium‐Catalyzed C–C Coupling Cascade Reactions: New Access to Electron‐Poor Polycyclic Aromatic Dicarboximides
Authors: Seifert Sabine , Schmidt David , Shoyama Kazutaka , Würthner Frank
Published: May 2017

Palladium‐catalyzed base‐selective annulation of dibromonaphthalimide to different aryl boronate esters by combined Suzuki–Miyaura cross‐coupling and direct C−H arylation afforded a series of new five‐ and six‐membered ring annulated electron‐poor polycyclic aromatic hydrocarbons. Cesium carbonate (Cs2CO3) as auxiliary base in these C−C coupling cascade reactions led exclusively to six‐membered ring annulation, while the use of organic base diazabicycloundecene (DBU) afforded the corresponding five‐membered ring annulated products. This base‐dependent selective mode of annulation is attributed to different mechanistic pathways directed by the applied base. The selective annulation was revealed by single crystal X‐ray analysis of the respective five‐ and six‐membered ring annulated products. The optical and redox properties of the new polycyclic aromatic dicarboximides were characterized by UV/Vis absorption and fluorescence spectroscopy and cyclic voltammetry.
Rapid Production of High‐Purity Hydrogen Fuel through Microwave‐Promoted Deep Catalytic Dehydrogenation of Liquid Alkanes with Abundant Metals
Authors: Jie Xiangyu , Gonzalez‐Cortes Sergio , Xiao Tiancun , Wang Jiale , Yao Benzhen , Slocombe Daniel R. , Al‐Megren Hamid A. , Dilworth Jonathan R. , Thomas John M. , Edwards Peter P.
Published: May 2017

Hydrogen as an energy carrier promises a sustainable energy revolution. However, one of the greatest challenges for any future hydrogen economy is the necessity for large scale hydrogen production not involving concurrent CO2 production. The high intrinsic hydrogen content of liquid‐range alkane hydrocarbons (including diesel) offers a potential route to CO2‐free hydrogen production through their catalytic deep dehydrogenation. We report here a means of rapidly liberating high‐purity hydrogen by microwave‐promoted catalytic dehydrogenation of liquid alkanes using Fe and Ni particles supported on silicon carbide. A H2 production selectivity from all evolved gases of some 98 %, is achieved with less than a fraction of a percent of adventitious CO and CO2. The major co‐product is solid, elemental carbon.
A Designed Approach to Enantiodivergent Enamine Catalysis
Authors: Macharia Juliet , Wambua Victor , Hong Yun , Harris Lawrence , Hirschi Jennifer S. , Evans Gary B. , Vetticatt Mathew J.
Published: May 2017

The rational design and implementation of enantiodivergent enamine catalysis is reported. A simple secondary amine catalyst, 2‐methyl‐l‐proline, and its tetrabutylammonium salt function as an enantiodivergent catalyst pair delivering the enantiomers of α‐functionalized aldehyde products in excellent enantioselectivities. This novel concept of designed enantiodivergence is applied to the enantioselective α‐amination, aldol, and α‐aminoxylation/α‐hydroxyamination reactions of aldehydes.
Heteroscorpionate‐based heteroleptic copper(II) complexes: Antioxidant, molecular docking and in vitro cytotoxicity studies
Authors: Jayakumar S. , Mahendiran D. , Viswanathan V. , Velmurugan D. , Kalilur Rahiman A.
Published: May 2017

Three new heteroscorpionate ligands, (2‐hydroxyphenyl)bis(imidazol‐1‐yl)methane (HL1), (4‐diethylamino‐2‐hydroxyphenyl)bis(imidazol‐1‐yl)methane (HL2) and (5‐bromo‐2‐hydroxyphenyl)bis(imidazol‐1‐yl)methane (HL3), and their heteroleptic copper(II) complexes of the type [Cu(L1–3)diimine]ClO4 (1–6; where diimine =2,2′‐bipyridyl or 1,10‐phenanthroline) have been synthesized and characterized using spectroscopic methods. The molecular structure of ligand HL1 was determined by single‐crystal X‐ray diffraction. UV–visible, electron paramagnetic resonance and theoretical studies suggest a distorted square pyramidal geometry around copper(II) ion. Analyses of highest occupied and lowest unoccupied molecular orbitals have been used to explain the charge transfer taking place within the complexes. The antioxidant activities of the heteroscorpionate ligands and their heteroleptic copper(II) complexes were determined using ABTS, DPPH and H2O2 free radical scavenging assays with respect to standard antioxidant ascorbic acid. In molecular docking studies, the complexes showed π–π, hydrogen bonding, van der Waals and electrostatic interactions with fibroblast growth factor receptor kinase. In vitro cytotoxicity activities of ligands and copper(II) complexes were examined on human breast adenocarcinoma (MCF‐7), cervical (HeLa) and lung (A549) cancer cell lines and normal human dermal fibroblast cell line using MTT assay. Complex 4 exhibited higher anticancer activity than the other complexes against all three cancer lines, being more potent than the standard drug cisplatin.
Preparation of recyclable polybutadiene rubber based on acid–base complexation
Authors: Cui Kejian , Wang Dong , Zhang Huan , Guo Jing , Cai Chao , Zhu Caizhen , Zhao Ning , Xu Jian
Published: May 2017

Thermoreversible polybutadiene (PB) rubber is prepared by the self‐assembly of thiol‐ene functionalized PB oligomers containing amine and carboxylic acid groups, respectively, via acid–base reaction. The as‐formed ionic hydrogen bonds between the amine and carboxylic acid groups function as the crosslinking points to construct the polymer network. By controlling the crosslinking density, a series of materials ranging from soft gel to stiff solid with different physical properties can be obtained. The thermal reversibility of the ionic hydrogen bonds is evidenced by rheometry and temperature‐dependent FTIR spectra. In contrast to conventional covalently crosslinked rubbers, the thermoreversible PB rubbers prepared exhibit the capability of thermally reshaping and recycling. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45280.
Palladium Nanoparticles Immobilized on Individual Calcium Carbonate Plates Derived from Mussel Shell Waste: An Ecofriendly Catalyst for the Copper‐Free Sonogashira Coupling Reaction
Authors: Saetan Trin , Lertvachirapaiboon Chutiparn , Ekgasit Sanong , Sukwattanasinitt Mongkol , Wacharasindhu Sumrit
Published: May 2017

The conversion of waste into high‐value materials is considered an important sustainability strategy in modern chemical industries. A large volume of shell waste is generated globally from mussel cultivation. In this work, mussel shell waste (Perna viridis) is transformed into individual calcium carbonate plates (ICCPs) and is applied as a support for a heterogeneous catalyst. Palladium nanoparticles (3–6 nm) are deposited with an even dispersion on the ICCP surface, as demonstrated by X‐ray diffraction and scanning electron microscopy. Using this system, Sonogashira cross‐coupling reactions between aryl iodides and terminal acetylenes were accomplished in high yields with the use of 1 % Pd/ICCP in the presence of potassium carbonate without the use of any copper metal or external ligand. The Pd/ICCP catalyst could also be reused up to three times and activity over 90 % was maintained with negligible Pd‐metal leaching. This work demonstrates that mussel shell waste can be used as an inexpensive and effective support for metal catalysts in coupling reactions, as demonstrated by the successful performance of the Pd‐catalyzed, copper‐free Sonogashira cross‐coupling process.
Activation of CO2 by Vanadium Nitrogenase
Authors: Sickerman Nathaniel S. , Hu Yilin , Ribbe Markus W.
Published: May 2017

The reduction of CO2 into useful products, including hydrocarbon fuels, is an ongoing area of particular interest due to efforts to mitigate buildup of this greenhouse gas. While the industrial Fischer–Tropsch process can facilitate the hydrogenation of CO2 with H2 to form short‐chain hydrocarbon products under high temperatures and pressures, a desire to perform these reactions under ambient conditions has inspired the use of biological approaches. Particularly, enzymes offer insight into how to activate and reduce CO2, but only one enzyme, nitrogenase, can perform the multielectron, multiproton reduction of CO2 into hydrocarbons. The vanadium‐containing variant, V‐nitrogenase, displays especial reactivity towards the hydrogenation of CO and CO2. This Focus Review discusses recent progress towards the activation and reduction of CO2 with three primary V‐nitrogenase systems. These systems span both ATP‐dependent and ATP‐independent processes and utilize approaches with whole cells, isolated proteins, and extracted cofactors.
Aqueous Oxidations Started by TiO2 Photoinduced Holes Can Be a Rate‐Determining Step
Authors: Gong Yuanzheng , Yang Chun , Ji Hongwei , Chen Chuncheng , Ma Wanhong , Zhao Jincai
Published: May 2017

In aqueous TiO2 photocatalytic hydroxylation of weakly polar aromatics, a series of inverse H/D KIEs of 0.7–0.8 were observed, which is different than the normal H/D kinetic isotope effects (KIEs) usually observed for polar aromatics. This result indicated that the oxidation started by photo‐induced hvb+ can be the rate‐determining step.
Exponential Stability and Stabilization for Quadratic Discrete‐Time Systems with Time Delay
Authors: Chen Fu , Kang Shugui , Qiao Shidong , Guo Caixia
Published: May 2017

In this note, we deal with the exponential stability and stabilization problems for quadratic discrete‐time systems with time delay. By using the quadratic Lyapunov function and a so called ‘Finsler's lemma', delay‐independent sufficient conditions for local stability and stabilization for quadratic discrete‐time systems with time delay are derived in terms of linear matrix inequalities (LMIs). Based on these sufficient conditions, iterative linear matrix inequality algorithms are proposed for maximizing the stability regions of the systems. Finally, two examples are given to illustrate the effectiveness of the methods presented in this paper.
A naphthalene derivative as ‘turn‐on’ fluorescent chemosensor for the highly selective and sensitive detection of Al3+
Authors: Zhu Zhong‐Xin , Yu Dong‐Dong , Liu Zhi‐Guo , Huang Ye‐Wei , Zhou A‐Yi , Chen Zhi‐Wei , Sun Jia , Wang Xu , Jin Li‐Tai , Cong Wei‐Tao
Published: May 2017

A Schiff base compound derived from naphthalene has been synthesized and characterized as an Al3+‐selective fluorescent probe. The chemosensor (L) exhibits high selectively for Al3+ in aqueous solution, even in the presence of biologically relevant cations such as Na+, K+, Ca2+, Mg2+, Pb2+ and several transition metal ions. There was no observed interference from anions like Br−, Cl−, HSO3−, SO32−, S2O32−, NO2−, CO32− and AC−. The lowest detection limit for the chemosensor L was found to be 1.89 × 10−8 M with a linear response towards Al3+ over a concentration range of 5 × 10−6 to 4 × 10−5 M. Furthermore, the proposed chemosensor has been used for imaging of Al3+ in two different types of cells with satisfying results, which further demonstrates its value for practical application in biological systems.
Novel Gallium Polyoxometalate/Nano‐Gold Hybrid Material Supported on Nano‐sized Silica for Mild Cyclohexene Oxidation Using Molecular Oxygen
Authors: Jameel Umsa , Zhu Mingqiao , Chen Xinzhi , Chen Hengquan , Iqbal Nousheen , Tong Zhangfa , Timayo Satmon John
Published: May 2017

Selective oxidation of olefins using molecular oxygen is a great challenge. This study reports two types of novel eco‐friendly heterogeneous hybrid catalysts. One comprises of a lacunary Keggin‐type polyoxometalate (POM) GaW11
linked to nano‐sized silica using (3‐aminopropyl) triethoxysilane (APTES) to form GaW11‐APTES@SiO2
. Another catalyst is Au/GaW11‐APTES@SiO2
prepared by wet deposition of nano‐gold on the former one. The catalysts were characterized and used for the solvent‐free oxidation of cyclohexene with molecular oxygen under mild reaction conditions. Both the catalysts showed good conversion and significant selectivity towards oxidized products for cyclohexene. GaW11‐APTES@SiO2
showed a high conversion of up to 62.02% with a selectivity of 59.13% towards epoxide at a mild temperature of 50°C. Au/GaW11‐APTES@SiO2
showed a conversion of 69.32% with 57.34% selectivity to 2‐cyclohexene‐1‐ol at a temperature of 80°C. The heterogeneous catalysts were reused several times with no significant loss in conversion or selectivity towards the oxidized products.
Manganese‐enhanced magnetic resonance imaging combined with electrophysiology in the evaluation of visual pathway in experimental rat models with monocular blindness
Authors: Tang Zuohua , Wang Jie , Xiao Zebin , Sun Xinghuai , Feng Xiaoyuan , Tang Weijun , Chen Qian , Wu Lingjie , Wang Rong , Zhong Yufeng , Wang Wentao , Luo Jianfeng
Published: May 2017

Purpose

Our study aimed to explore the feasibility of manganese‐enhanced magnetic resonance imaging (MEMRI) combined with visual evoked potentials (VEP) and auditory evoked visual cortex responses (AVR) in evaluating for the establishment of visual/auditory compensatory pathways after monocular blindness.

Materials and Methods

A total of 14 healthy neonatal male Sprague‐Dawley rats were randomly divided into two groups (n = 7 for Groups A and B). Right optic nerve (ON) transection was performed on the 7 rats of Group A to obtain a monocularly blind model, and the 7 rats of Group B were chosen as the control group. Four months later, 400 mmol MnCl2 was injected into the left eye in both groups via intravitreal injection. The changes in the visual pathways projected from the blind eye and the remaining eye in Group A and the normal eyes in Group B were compared to determine if new visual compensatory pathways were established. Additionally, VEP tests were performed to determine complete blindness, and AVR examinations were performed to help identify the generation of auditory compensatory function.

Results

The VEP test indicated complete visual loss after ON transection. In the monocularly blind rats, the contrast‐to‐noise ratio (CNR) of ON, optic tract (OT), lateral geniculate nucleus (LGN), superior colliculus (SC), optic radiation (OR) and visual cortex (VC) of visual pathway projected from the left eye was significantly higher than that of the right pathway (p < .001). Moreover, the CNR of ON, OT, LGN, SC, OR and VC in the visual pathway projected from the left eye of monocularly blind rats was significantly lower than those of normal rats (p < .05). The AVR results revealed that the corresponding bilateral visual cortex in monocularly blind rats did not respond to the auditory stimulus or showed dissimilation with the low frequency.

Conclusion

MEMRI combined with electrophysiology, including VEP and AVR, may be potentially helpful in the evaluation of the possible generation of new visual/auditory compensatory pathways after monocular blindness.