bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition‐Metal‐Doped NIR‐Emitting Silicon Nanocrystals
Authors: Chandra Sourov , Masuda Yoshitake , Shirahata Naoto , Winnik Françoise M. 
Published: April 2017

AbstractImpurity‐doping in nanocrystals significantly affects their electronic properties and diversifies their applications. Herein, we report the synthesis of transition metal (Mn, Ni, Co, Cu)‐doped oleophilic silicon nanocrystals (SiNCs) through hydrolysis/polymerization of triethoxysilane with acidic aqueous metal salt solutions, followed by thermal disproportionation of the resulting gel into a doped‐Si/SiO2 composite that, upon HF etching and hydrosilylation with 1‐n‐octadecene, produces free‐standing octadecyl‐capped doped SiNCs (diameter≈3 to 8 nm; dopant <0.2 atom %). Metal‐doping triggers a red‐shift of the SiNC photoluminescence (PL) of up to 270 nm, while maintaining high PL quantum yield (26 % for Co doping).
Ligand Design for Site‐Selective Metal Coordination: Synthesis of Transition‐Metal Complexes with η6‐Coordination of the Central Ring of Anthracene
Authors: Karslyan Eduard E. , Borissova Alexandra O. , Perekalin Dmitry S. 
Published: April 2017

AbstractA polycyclic aromatic ligand for site‐selective metal coordination was designed by using DFT calculations. The computational prediction was confirmed by experiments: 2,3,6,7‐tetramethoxy‐9,10‐dimethylanthracene initially reacts with [(C5H5)Ru(MeCN)3]BF4 to give the kinetic product with a [(C5H5)Ru]+ fragment coordinated at the terminal ring, which is then transformed into the thermodynamic product with coordination through the central ring. These isomeric complexes have markedly different UV/Vis spectra, which was explained by analysis of the frontier orbitals. At the same time, the calculations suggest that electrostatic interactions are mainly responsible for the site selectivity of the coordination.
Enantioselective Palladium(II)‐Catalyzed Intramolecular Aminoarylation of Alkenes by Dual N−H and Aryl C−H Bond Cleavage
Authors: Zhang Wen , Chen Pinhong , Liu Guosheng 
Published: April 2017

AbstractAn asymmetric palladium‐catalyzed intramolecular oxidative aminoarylation of alkenes has been developed with quinoline–oxazoline chiral ligands and Ag2CO3 as the oxidant. Various indolines containing a quaternary stereogenic center were synthesized in high yield with excellent enantioselectivity. Preliminary mechanistic studies suggest that the addition of a catalytic amount of phenylglyoxylic acid significantly accelerates the reaction and slightly enhances the enantioselectivity.
Proximity‐Based Sortase‐Mediated Ligation
Authors: Wang Hejia Henry , Altun Burcin , Nwe Kido , Tsourkas Andrew 
Published: April 2017

AbstractProtein bioconjugation has been a crucial tool for studying biological processes and developing therapeutics. Sortase A (SrtA), a bacterial transpeptidase, has become widely used for its ability to site‐specifically label proteins with diverse functional moieties, but a significant limitation is its poor reaction kinetics. In this work, we address this by developing proximity‐based sortase‐mediated ligation (PBSL), which improves the ligation efficiency to over 95 % by linking the target protein to SrtA using the SpyTag–SpyCatcher peptide–protein pair. By expressing the target protein with SpyTag C‐terminal to the SrtA recognition motif, it can be covalently captured by an immobilized SpyCatcher–SrtA fusion protein during purification. Following the ligation reaction, SpyTag is cleaved off, rendering PBSL traceless, and only the labeled protein is released, simplifying target protein purification and labeling to a single step.
Robust Binding between Carbon Nitride Nanosheets and a Binuclear Ruthenium(II) Complex Enabling Durable, Selective CO2 Reduction under Visible Light in Aqueous Solution
Authors: Kuriki Ryo , Yamamoto Muneaki , Higuchi Kimitaka , Yamamoto Yuta , Akatsuka Masato , Lu Daling , Yagi Shinya , Yoshida Tomoko , Ishitani Osamu , Maeda Kazuhiko 
Published: April 2017

AbstractCarbon nitride nanosheets (NS‐C3N4) were found to undergo robust binding with a binuclear ruthenium(II) complex (RuRu′) even in basic aqueous solution. A hybrid material consisting of NS‐C3N4 (further modified with nanoparticulate Ag) and RuRu′ promoted the photocatalytic reduction of CO2 to formate in aqueous media, in conjunction with high selectivity (approximately 98 %) and a good turnover number (>2000 with respect to the loaded Ru complex). These represent the highest values yet reported for a powder‐based photocatalytic system during CO2 reduction under visible light in an aqueous environment. We also assessed the desorption of RuRu′ from the Ag/C3N4 surface, a factor that can contribute to a loss of activity. It was determined that desorption is not induced by salt additives, pH changes, or photoirradiation, which partly explains the high photocatalytic performance of this material.
Reversible oxidative Addition an Kohlenstoff
Authors: Eichhorn Antonius F. , Fuchs Sonja , Flock Marco , Marder Todd B. , Radius Udo 
Published: April 2017

AbstractEs wird die Reaktivität N‐heterocyclischer Carbene (NHCs) und cyclischer Alkylaminocarbene (cAACs) gegenüber Arylboronsäureestern vorgestellt. Die Reaktionen mit NHCs führen zur reversiblen Bildung thermisch stabiler Lewis‐Säure‐Base‐Addukte Ar‐B(OR)2⋅NHC (Add1–Add6). Die Umsetzungen von cAACMe mit den Catecholboronsäureestern 4‐R‐C6H4Bcat (R=Me, OMe) liefern die Addukte 4‐R‐C6H4Bcat⋅cAACMe (Add7, R=Me) und (Add8, R=OMe), die bei Raumtemperatur zu den cAACMe‐Ringerweiterungsprodukten RER1 und RER2 reagieren. Die Boronsäureester Ar‐B(OR)2 des Pinakols, Neopentylglykols und Ethylenglykols reagieren bei Raumtemperatur mit cAACMe unter reversibler oxidativer Addition der B‐C‐Bindung an das Carben‐Kohlenstoffatom zu cAACMe(B{OR}2)(Ar) (BCA1–BCA6). NMR‐spektroskopische Untersuchungen an cAACMe(Bneop)(4‐Me‐C6H4) (BCA4) belegen die Reversibilität dieser oxidativen Addition am Kohlenstoffatom.
Fast NMR‐Based Determination of the 3D Structure of the Binding Site of Protein–Ligand Complexes with Weak Affinity Binders
Authors: Wälti Marielle A. , Riek Roland , Orts Julien 
Published: April 2017

AbstractIn early drug discovery approaches, screening hits are often weak affinity binders that are difficult to characterize in structural detail, particularly towards obtaining the 3D structure of protein–ligand complexes at atomic resolution. NMR is the outstanding technique to tackle such problems, yet suffers from a tedious structure calculation process. NMR2 was recently developed to alleviate the laborious element of routine NMR structure calculation procedures and provides the structural information at protein–ligand interaction sites orders of magnitude faster than standard procedures. The NMR2 method was extended to weak binders and applied to the oncoproteins HDM2 and MDMX. The structure of the MDMX‐SJ212 complex is reported with a Kd of approximately 0.7 μm; the complex structure of HDM2 with the mm affinity ligand #845 exhibits a new scaffold.
Domino N‐/C‐Arylation via In Situ Generation of a Directing Group: Atom‐Efficient Arylation Using Diaryliodonium Salts
Authors: Teskey Christopher J. , Sohel Shariar M. A. , Bunting Danielle L. , Modha Sachin G. , Greaney Michael F. 
Published: April 2017

AbstractBoth aryl components of diaryliodonium salts can be used in a domino one‐pot reaction via in situ generation of a directing group. A number of heterocycles undergo N‐arylation which is followed by ruthenium‐catalyzed C‐arylation. Notably the reaction extends well to unsymmetrical diaryliodonium salts with a number of highly selective examples shown.
Intramolecular Benzoin Reaction Catalyzed by Benzaldehyde Lyase from Pseudomonas Fluorescens Biovar I
Authors: Hernández Karel , Parella Teodor , Petrillo Giovanna , Usón Isabel , Wandtke Claudia M. , Joglar Jesús , Bujons Jordi , Clapés Pere 
Published: April 2017

AbstractIntramolecular benzoin reactions catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I (BAL) are reported. The structure of the substrates envisaged for this reaction consists of two benzaldehyde derivatives linked by an alkyl chain. The structural requirements needed to achieve the intramolecular carbon–carbon bond reaction catalyzed by BAL were established. Thus, a linker consisting of a linear alkyl chain of three carbon atoms connected through ether‐type bonds to the 2 and 2′ positions of two benzaldehyde moieties, which could be substituted with either Cl, Br, or OCH3 at either the 3 and 3′ or 5 and 5′ positions, were suitable substrates for BAL. Reactions with 61–84 % yields of the intramolecular product and ee values between 64 and 98 %, were achieved.
Arrangement of Proteinogenic α‐Amino Acids on a Cyclic Peptide Comprising Alternate Biphenyl‐Cored ζ‐Amino Acids
Authors: Tashiro Shohei , Chiba Masayuki , Shionoya Mitsuhiko 
Published: April 2017

AbstractAiming at precisely arranging several proteinogenic α‐amino acids on a folded scaffold, we have developed a cyclic hexapeptide comprising an alternate sequence of biphenyl‐cored ζ‐amino acids and proteinogenic α‐amino acids such as l‐leucine. The amino acids were connected by typical peptide synthesis, and the resultant linear hexapeptide was intramolecularly cyclized to form a target cyclic peptide. Theoretical analyses and NMR spectroscopy suggested that the cyclic peptide was folded into an unsymmetrical conformation, and the structure was likely to be flexible in CHCl3. The optical properties including UV/Vis absorption, fluorescence, and circular dichroism (CD) were also evaluated. Furthermore, the cyclic peptide became soluble in water by introducing three carboxylate groups at the periphery of the cyclic skeleton. This α/ζ‐alternating cyclic peptide is therefore expected to serve as a unique scaffold for arranging several functionalities.
Ambient‐Pressure Stabilization of β‐GdB3O6 by Doping with Bi3+ and Color‐Tunable Emissions by Co‐Doping with Tb3+ and Eu3+: The First Photoluminescence Study of a High‐Pressure Polymorph
Authors: Sun Xiaorui , Jiang Pengfei , Gao Wenliang , Zhou Xianju , Cong Rihong , Yang Tao 
Published: April 2017

AbstractRare‐earth borates are good candidates for optical applications. To date, however, the high‐pressure/high‐temperature technique has produced a large number of novel borates with optical properties that have rarely been investigated due to the severe problem of substantial defects. We targeted the high‐pressure polymorph of β‐GdB3O6 and synthesized three solid solutions of β‐Gd0.75−xBi0.25TbxB3O6 (0≤x≤0.75), β‐Gd0.75−yBi0.25EuyB3O6 (0≤y≤0.75), and β‐Gd0.50−zBi0.25Tb0.25EuzB3O6 (0≤z≤0.05) by using typical solid‐state reactions at 820 °C. Here, the function of Bi3+ is to stabilize the high‐pressure phase by lowering the synthetic temperature and being the sensitizer to promote the green and red emissions of Tb3+ and Eu3+. The multiple energy transfer paths were investigated by using lifetime decay experiments and photoluminescent spectra, and both efficiency and mechanism were determined. Eventually, color‐tunable and white emissions were achieved by rational doping of Bi3+, Tb3+, and Eu3+ into β‐GdB3O6, that is, the CIE chromaticity coordinate for β‐Gd0.44Bi0.25Tb0.30Eu0.01B3O6 is (0.318, 0.365) with a correlated color temperature of 6101 K.
Hydrophobic‐hydrophilic forces in protein folding
Authors: Durell Stewart R. , Ben‐Naim Arieh 
Published: April 2017

AbstractThe process of protein folding is obviously driven by forces exerted on the atoms of the amino‐acid chain. These forces arise from interactions with other parts of the protein itself (direct forces), as well as from interactions with the solvent (solvent‐induced forces). We present a statistical–mechanical formalism that describes both these direct and indirect, solvent‐induced thermodynamic forces on groups of the protein. We focus on 2 kinds of protein groups, commonly referred to as hydrophobic and hydrophilic. Analysis of this result leads to the conclusion that the forces on hydrophilic groups are in general stronger than on hydrophobic groups. This is then tested and verified by a series of molecular dynamics simulations, examining both hydrophobic alkanes of different sizes and hydrophilic moieties represented by polar‐neutral hydroxyl groups. The magnitude of the force on assemblies of hydrophilic groups is dependent on their relative orientation: with 2 to 4 times larger forces on groups that are able to form one or more direct hydrogen bonds.
Association of anti‐gangliosides antibodies and anti‐CMV antibodies in Guillain–Barré syndrome
Authors: Wang Lijuan , Shao Chunqing , Yang Chunjiao , Kang Xixiong , Zhang Guojun 
Published: April 2017

AbstractIntroductionNumerous types of infection were closely related to GBS, mainly including Campylobacter jejuni, Cytomegalovirus, which may lead to the production of anti‐gangliosides antibodies (AGA). Currently, although there are increased studies on the AGA and a few studies of anti‐CMV antibodies in GBS, the association between them remains poorly documented. Therefore, our research aims to analyze the correlation of anti‐CMV antibodies and AGA in GBS.MethodsA total of 29 patients with GBS were enrolled in this study. The CMV antibodies were tested by the electrochemiluminescence immunoassay “ECLIA” (Roche Diagnostics GmbH). The serum gangliosides were determined by The EUROLINE test kit.ResultsOf the 29 patients with GBS, 9 (31%) were AGA‐seropositive, in which 22 were CMV‐IgG positive in CSF at the same time, but all 29 samples were CMV‐IgM negative in both serum and CSF. In the AGA‐positive group, the rate of both serum and CSF positive was 87.5% (7/8), higher than 50% (7/14) of the negative group, although no statistical significance was found. In addition, we found that there was a trend of higher ratio of men, a younger age onset, less frequent preceding infection, a higher level of CSF proteins, and less frequent cranial nerve deficits, although the data did not reach a statistical significance.ConclusionIn spite of no statistical significance association was found between serum AGA and CMV‐IgG in serum and CSF. However, we found that there was a trend of high positive rate of both serum and CSF‐CMV‐IgG in AGA‐positive than the negative group. So we should further expand the sample size to analyze the association between AGA and CMV or other neurotropic virus antibodies in various diseases, to observe whether they could be serological marker of these diseases (especially GBS) or the underlying pathogenesis.
Effects of levodopa/carbidopa intestinal gel versus oral levodopa/carbidopa on B vitamin levels and neuropathy
Authors: Loens Sebastian , Chorbadzhieva Elena , Kleimann Alexandra , Dressler Dirk , Schrader Christoph 
Published: April 2017

AbstractObjectivesTo determine the possible interactions between levodopa therapy and plasma levels of B vitamins in patients with advanced idiopathic Parkinson's disease (IPD) in the context of either oral levodopa therapy or levodopa/carbidopa intestinal gel (LCIG). Secondly, to determine the prevalence of neuropathy and its relation to plasma levels of B vitamins and homocysteine.MethodsMedication doses, neurographies, and serum levels of pyridoxine, cobalamin, folate, and homocysteine of eight LCIG and 13 orally treated advanced IPD patients matched for age, Hoehn & Yahr stage, and UPRDS III were collected. This data was analyzed for correlation with daily levodopa dose (LDD).ResultsLICG patients had a longer disease duration and higher LDD. All LCIG patients and most orally treated patients had sensorimotor axonal polyneuropathy. Of all plasma vitamin levels, pyridoxine was decreased most and significantly lower in the LCIG group. Cobalamin and folate, however, were within the lower reference range, and homocysteine highly elevated, all without any significant difference between both groups. LDD correlated significantly with pyridoxine deficiency (p = .02) irrespective of the route of application and with hyperhomocysteinemia in the LCIG group (p = .03). At LDDs above 2,000 mg, pyridoxine deficiency was almost always detectable.ConclusionsPyridoxine deficiency and hyperhomocysteinemia are dependent on the daily levodopa/carbidopa dose, while levels of cobalamin and folate are not. The mode of application of levodopa/carbidopa has no impact on B‐vitamin levels. Neuropathy is very frequent in advanced IPD; however, it remains to be investigated further whether neuropathy is more frequent in LCIG than in orally levodopa/carbidopa‐treated advanced IPD patients.
Personal experience and critical reflexivity in counselling and psychotherapy research
Authors: Etherington Kim 
Published: April 2017

AbstractAimsThe aim of this study was to offer a view of how, as a counselling practitioner‐researcher, I use my personal experiences reflexively in research. By ‘showing’ and ‘telling’ about the practices and processes involved, I hope to encourage others to undertake research that values reflexive collaborative engagement and enables participants’ agency in research.MethodsI address the value of critical reflexivity as a means for including ourselves and our personal experiences in counselling and psychotherapy research. Three excerpts are offered as examples of (a) reflexively contextualising ourselves and our participants, (b) reflexively co‐constructing knowledge and meaning making and (c) a critically reflexive approach to addressing issues of voice in research by highlighting a potential dilemma about choosing which stories should be told.
Cytoskeletal mechanisms in positioning of the second‐division spindles and meiotic restitution in tobacco (Nicotiana tabacum L.) microsporogenesis
Authors: Sidorchuk Yuriy Vladimirovich , Deineko Elena Victorovna 
Published: April 2017

AbstractMicrosporogenesis patterns of the polyploid (2n = 4x = 96) and diploid (2n = 2x = 48) Nicotiana tabacum L. (cv. Havana Petit line SR1) plants have been analyzed and compared. Four types of abnormal positions of the second‐division spindles—tripolar, parallel, proximal, and fused—have been observed. Of these abnormalities, only tripolar (2.4%) and parallel (1.4%) spindles are observable in diploid plants. As for polyploids, the increased ploidy is accompanied by an increase in the incidence of tripolar (22.8%) and parallel (8.1%) spindle orientations and emergence of two remaining abnormalities (proximal and fused spindles, 3.3%). As has been shown, the spindle position abnormalities in diploid plants have no effect on the meiotic products, whereas both dyads and triads are detectable among the tetrads in polyploid plants. Analysis of cytoskeletal remodeling has allowed for the insight into the role of interzonal radial microtubule system in spindle positioning during the second division. The reason underlying the change in spindle positioning is disturbed polymerization–depolymerization processes and interdigitation of microtubule plus ends within the interzonal cytoskeleton system in late telophase I–interkinesis and prophase II. As has been demonstrated, fused second‐division spindles are formed as a result of fused cytoskeletal structures in prophase–prometaphase II in the case when the nuclei are drawn abnormally close to one another.
Hypoglycemia and decreased insulin requirement caused by malignant insulinoma in a type 1 diabetic patient: when the hoof beats are from a zebra, not a horse
Authors: Gjelberg Hilde K. , Hoem Dag , Verbeke Caroline S. , Eide Johan , Cooper John G. , Molven Anders 
Published: April 2017

Key Clinical MessageInsulinomas are uncommon tumors, and in patients with diabetes mellitus they are extremely rare. We describe a patient with type 1 diabetes who developed malignant insulinoma. When hypoglycemic episodes persist in a patient with diabetes and treatment‐induced and other causes of hypoglycemia have been ruled out, an insulin‐producing tumor should be considered.
Synthesis of Platinum Nanoparticles by Reductive Crystallization Using Polyethyleneimine
Authors: Nagao Hideyuki , Ichiji Masumi , Hirasawa Izumi 
Published: April 2017

AbstractSub‐10‐nm‐sized Pt nanoparticles were synthesized by reducing Pt ions with NaBH4, with the addition of polyethyleneimine (PEI) as a protective reagent. Well‐dispersed Pt nanoparticles with a narrow size distribution were successfully produced. When lowering the pH of the PEI solution, cubic and tetrahedral nanoparticles were observed, while at a higher pH, only spherical nanoparticles were produced. In addition, by selecting a suitable concentration of PEI, the protective reagent itself can reduce Pt ions to generate Pt nanoparticles with diameters in the range of 12.9–70.7 nm. This shows the potential of one‐pot synthesis of Pt nanoparticles by just adding Pt ions and PEI.
Hemilability‐Driven Water Activation: A NiIICatalyst for Base‐Free Hydration of Nitriles to Amides
Authors: Singh Kuldeep , Sarbajna Abir , Dutta Indranil , Pandey Pragati , Bera Jitendra K. 
Published: April 2017

AbstractThe NiIIcomplex1containing pyridyl‐ and hydroxy‐functionalized N‐heterocyclic carbenes (NHCs) is synthesized and its catalytic utility for the selective nitrile hydration to the corresponding amide under base‐free conditions is evaluated. The title compound exploits a hemilabile pyridyl unit to interact with a catalytically relevant water molecule through hydrogen‐bonding and promotes a nucleophilic water attack to the nitrile. A wide variety of nitriles is hydrated to the corresponding amides including the pharmaceutical drugs rufinamide, Rifater, and piracetam. Synthetically challenging α‐hydroxyamides are accessed from cyanohydrins under neutral conditions. Related catalysts that lack the pyridyl unit (i.e., compounds2and4) are not active whereas those containing both the pyridyl and the hydroxy or only the pyridyl pendant (i.e., compounds1and3) show substantial activity. The linkage isomer1′where the hydroxy group is bound to the metal instead of the pyridyl group was isolated under different crystallization conditions insinuating a ligand hemilabile behavior. Additional pKameasurements reveal an accessible pyridyl unit under the catalytic conditions. Kinetic studies support a ligand‐promoted nucleophilic water addition to a metal‐bound nitrile group. This work reports a Ni‐based catalyst that exhibits functional hemilability for hydration chemistry.
DHMO, die wässrige Gefahr
Authors: Roth Klaus 
Published: April 2017

AbstractMoleküle und ihre Beziehung zu uns Menschen sollen in dieser Rubrik vorgestellt werden, die daher auch “Moleküle und Menschen” heißt und den Berliner “Molecule Man” des US‐amerikanischen Bildhauers Jonathan Borofsky (*1942) als Logo trägt. Er selbst sagt über sein Kunstwerk: “Für mich steht diese 30 m hohe Aluminium‐Skulptur von drei, sich im Mittelpunkt treffenden Figuren nicht nur für die Leichtigkeit unserer eigenen massiven Körper, sondern die drei, im Zentrum miteinander verbundenen Figuren stehen für die Vereinigung der Moleküle aller Menschen, um unsere Existenz zu erschaffen.” In diesem Aprilheft geht es um Dihydrogenmonoxid .
Schneller als der Arzt erlaubt
Authors: Tetsch Larissa 
Published: April 2017

AbstractKegelschnecken [1] lähmen ihre Beutetiere mit Hilfe eines Giftcocktails. Bei den Fische jagenden Landkartenkegelschnecken enthält dieser Insulin, das einen plötzlichen Blutzuckerabfall der Beute verursacht. Im Vergleich zu menschlichem Insulin ist das Schneckeninsulin extrem schnell wirksam, und könnte somit als Leitmolekül für ein neues Diabetespräparat dienen.
f‐Gruppen‐Chemie: Opposition erwünscht
Authors: Groß Michael 
Published: April 2017

AbstractDas Krebsmedikament cis‐Platin verdankt seinen Namen der Verteilung der quadratisch‐planar angeordneten Liganden, zwei Ammoniakgruppen und zwei Chloridionen. Nur wenn die beiden NH3‐Liganden auf benachbarten Ecken des Quadrats sitzen, also in cis‐Stellung, blockiert der Komplex die Zell‐teilung und ist deshalb gegen Krebs wirksam. Stehen sie sich diagonal gegenüber, so liegt das trans‐Isomere vor, das unwirksam ist. Da trifft es sich gut, dass bei der Synthese des Medikaments der so genannte trans‐Effekt hilft.