bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcription factor organic cation transporter 1 (OCT-1) affects the expression of porcine Klotho (KL) gene
Authors: Li Yan , Wang Lei , Zhou Jiawei , Li Fenge
Published: July 2016

Klotho (KL), originally discovered as an aging suppressor, is a membrane protein that shares sequence similarity with theβ-glucosidase enzymes. Recent reports showed Klotho might play a role in adipocyte maturation and systemic glucose metabolism. However, little is known about the transcription factors involved in regulating the expression of porcineKLgene. Deletion fragment analysis identified KL-D2 (−418 bp to −3 bp) as the porcineKLcore promoter. MARC0022311SNP (A or G) in KL intron 1 was detected in Landrace × DIV pigs using the Porcine SNP60 BeadChip. The pGL-D2-A and pGL-D2-G were constructed with KL-D2 and the intron fragment of different alleles and relative luciferase activity of pGL3-D2-G was significantly higher than that of pGL3-D2-A in the PK cells and ST cells. This was possibly the result of a change inKLbinding ability with transcription factor organic cation transporter 1 (OCT-1), which was confirmed using electrophoretic mobility shift assays (EMSA) and chromatin immune-precipitation (ChIP). Moreover, OCT-1 regulated endogenousKLexpression by RNA interference experiments. Our study indicates SNP MARC0022311 affects porcineKLexpression by regulating its promoter activity via OCT-1.
Association between aberrant APC promoter methylation and breast cancer pathogenesis: a meta-analysis of 35 observational studies
Authors: Zhou Dan , Tang Weiwei , Wang Wenyi , Pan Xiaoyan , An Han-Xiang , Zhang Yun
Published: July 2016

Background.Adenomatous polyposis coli (APC) is widely known as an antagonist of the Wnt signaling pathway via the inactivation ofβ-catenin. An increasing number of studies have reported that APC methylation contributes to the predisposition to breast cancer (BC). However, recent studies have yielded conflicting results.

Methods.Herein, we systematically carried out a meta-analysis to assess the correlation between APC methylation and BC risk. Based on searches of the Cochrane Library, PubMed, Web of Science and Embase databases, the odds ratio (OR) with 95% confidence interval (CI) values were pooled and summarized.

Results.A total of 31 articles involving 35 observational studies with 2,483 cases and 1,218 controls met the inclusion criteria. The results demonstrated that the frequency of APC methylation was significantly higher in BC cases than controls under a random effect model (OR= 8.92, 95% CI [5.12–15.52]). Subgroup analysis further confirmed the reliable results, regardless of the sample types detected, methylation detection methods applied and different regions included. Interestingly, our results also showed that the frequency of APC methylation was significantly lower in early-stage BC patients than late-stage ones (OR= 0.62, 95% CI [0.42–0.93]).

Conclusion.APC methylation might play an indispensable role in the pathogenesis of BC and could be regarded as a potential biomarker for the diagnosis of BC.
Justicia comunitaria o de las razones para disentir
Authors: De Souza Thaisa
Published: July 2016

El presente ensayo reflexiona en torno al problema de la justicia comunitaria como posibilidad para desenredar las ambiguas lógicas tutelares de pacificación y sometimiento. Esto invita a repensar los fines y confines de lo que revela la tradición política moderna. Para ello, comienzo analizando dos categorías clave: pacificación y confinamiento, las cuales constituyen lo que se podría llamar paradoja erosionadora de los derechos. Posteriormente, se aborda el tiempo y su papel de formador del entendimiento y de la interpretación de las injusticias cometidas, incluyendo al individuo y su padecimiento. Luego, busco postular la asunción de dos vertientes progenitoras de los modos de enlazar la justicia a los distintos contextos de sentido: el lenguaje del conflicto y la interpelación moral de los sujetos; proyectando así las necesarias acciones de articulación de los disensos. Finalizo exponiendo una idea de proyecto ético-político de materialización de justicias comunitarias, que reposara sobre la triple agencia pedagógica de la afirmación del lenguaje, la invocación colectiva de acontecimientos para articular las memorias y la legitimación cohesionadora de saberes. El objetivo es demostrar que el derecho gobernante, sea cual sea su lenguaje, parece redundar en una máquina práctica y pensamiento ajustado a las contingencias normativas de creación de hegemonías y categorías discursivas, ante lo cual es necesario generar propuestas contra-hegemónicas del derecho, como es la llamada justicia comunitaria.
Percepción de la violencia en el noviazgo entre universitarios: ¿control o amor?
Authors: Flores Palacios María Leticia , Juárez Delgado Carolina , Vidaña Jácome Diana Carolina
Published: July 2016

La violencia en el noviazgo es tema central de múltiples trabajos de investigación, en este estudio en particular, se analizó la percepción de la violencia en el noviazgo por parte de jóvenes universitarios. Entre los resultados más importantes se encontró que la violencia psicológica y emocional que consiste en mantener el control y en utilizar apodos para humillar, resulta ser la más común. Ambos sexos coinciden en que tanto hombres como mujeres, son agresores y receptores de este tipo de violencia.
Resíduos de atrazine e de tembotrione no solo afetam o crescimento inicial da beterraba
Authors: França Gabriel Venâncio da Silva , Oliveira Guilherme Anthony , Melo Christiane Augusta Diniz , Silva Gustavo Soares , Carneiro Gabriella Daier Oliveira Pessoa , Silva Daniel Valadão , Reis Marcelo Rodrigues
Published: July 2016

O cultivo da beterraba é frequentemente realizado em sistema de rotação de culturas com cereais como o milho. Neste caso, herbicidas com efeito residual aplicados durante o cultivo do milho podem prejudicar o estabelecimento e o crescimento da beterraba cultivada em sucessão. Diante disso, três experimentos foram conduzidos em casa de vegetação para avaliar o efeito residual dos herbicidas atrazine e tembotrione, isolados ou em mistura, sobre o crescimento inicial da beterraba. Os tratamentos consistiram de seis doses correspondentes a 0, 10, 20, 30, 40 e 50% da dose recomendada. As avaliações realizadas foram: intoxicação das plantas, matéria seca da parte aérea e índice SPAD. O atrazine e tembotrione provocaram efeito negativo sobre o crescimento inicial da beterraba, apresentando redução nos valores de matéria seca da parte aérea e do índice SPAD, bem como aumento da intoxicação com o incremento das doses. Quando os herbicidas foram aplicados em mistura o efeito foi potencializado, causando a morte das plantas nas maiores doses (40 e 50%). Em função desses resultados, o cultivo de beterraba após a aplicação de atrazine e, ou tembotrione na cultura do milho pode tornar-se inviável devido ao potencial de carryover nessas situações.
Associação dos herbicidas diclosulam e glyphosate na dessecação visando o controle residual de plantas daninhas na cultura da soja
Authors: Santos Tássia Tuane Moreira dos , Timossi Paulo César , Lima Suzete Fernandes , Gonçalves Dênio Celestino , Santana Marcus Vinícius
Published: July 2016

A associação dos herbicidas glyphosate e diclosulam na dessecação pode diminuir a presença de plantas daninhas por maior período, favorecendo assim o desenvolvimento e a produtividade das plantas de soja. Objetivou-se verificar a eficiência do herbicida diclosulam associado ao glyphosate, na dessecação para plantio direto da cultura de soja RR, cultivada no sistema plante e aplique. A cobertura vegetal presente foi Urochloa ruziziensis com 4,4 t ha-1, distribuída uniformemente sobre a área experimental. O delineamento experimental utilizado foi o de blocos ao acaso com três tratamentos e 4 repetições. Os tratamentos constituíram-se na aplicação de glyphosate a 1,2 kg ha-1 de equivalente ácido (e.a.) + diclosulam a 25,2 g ha-1 de ingrediente ativo (i.a.) em pré-semeadura da cultura sem a aplicação complementar, glyphosate a 1,2 kg ha-1 de e.a. + diclosulam a 25,2 g ha-1 de i.a. em pré-semeadura da cultura + glyphosate a 1,2 kg ha-1e.a. em complementação e glyphosate a 1,2 kg ha-1 de e.a. em pré-semeadura + glyphosate a 1,2 kg ha-1 de e.a. em complementação. Foram avaliados os seguintes parâmetros: reinfestação inicial e densidade relativa de plantas daninhas aos 31 dias após a dessecação, reinfestação de plantas daninhas no período da colheita, dificuldade de colheita mecanizada, número de vagens por planta, peso de 1000 grãos e produtividade de grãos. A associação do herbicida diclosulam ao glyphosate auxilia no manejo inicial da comunidade infestante no cultivo da soja, sem, no entanto, dispensar a aplicação complementar do herbicida glyphosate.
Diferenciando o espaço e produzindo cidades: lógicas e agentes da produção do espaço urbano nas cidades de Ribeirão Preto/SP e Londrina/PR
Authors: Abreu Marlon Altavini
Published: July 2016

O presente trabalho coloca em uma perspectiva comparada os mercados imobiliários de duas cidades médias brasileiras. Trabalhando com dados de anúncios imobiliários de terrenos, no período compreendido entre os anos de 1995 a 2010, para as cidades de Ribeirão Preto/SP e Londrina/PR, além de outras diversas fontes de informação, busca-se compreender alguns dos traços contemporâneos de sua produção e das condições de seu consumo. Toma-se como referência a redefinição das lógicas de produção do espaço urbano em geral e das cidades em particular, confrontando-se características tais como a continuidade dos tecidos urbanos e a amplificação das dinâmicas de diferenciação interna da cidade. A partir das particularidades da produção imobiliária, são observadas redefinições nas estratégias espaciais de atuação dos agentes e na ampliação de seu poder econômico sobre as práticas de produzir e se apropriar das cidades.
Impact of aerosols on precipitation from deep convective clouds in eastern China
Authors: Jiang Mengjiao , Li Zhanqing , Wan Bingcheng , Cribb Maureen
Published: July 2016

We analyzed the impact of aerosols on precipitation based on 3 years of 3‐hourly observations made in heavily polluted eastern China. The probability of precipitation from different cloud types was calculated using International Satellite Cloud Climatology Project cloud data and gauge‐based hourly precipitation data. Because deep convective clouds have the largest precipitation probability, the influence of aerosols on the precipitation from such clouds was studied in particular. Aerosol properties were taken from the Modern‐Era Retrospective Analysis for Research and Applications Aerosol Reanalysis data set. As aerosol optical depth increased, rainfall amounts from deep convective clouds increased at first and then decreased. The descending part of the trend is likely due to the aerosol radiative effect. Downwelling solar radiative fluxes at the surface decreased as aerosol optical depth increased. The decrease in solar radiation led to a decrease in ground heat fluxes and convective available potential energy, which is unfavorable for development of convective clouds and precipitation. The tendencies for lower cloud top temperatures, lower cloud top pressures, and higher cloud optical depths as a response to larger aerosol optical depths suggest the invigoration effect. Vertical velocity, relative humidity, and air temperature from the National Centers for Environmental Prediction Climate Forecast System Reanalysis were sorted to help investigate if the trends are dependent on any environmental conditions. How dynamic and microphysical factors strengthen or mitigate the impact of aerosols on clouds and precipitation and more details about their interplay should be studied further using more observations and model simulations.
White Arctic vs. Blue Arctic: A case study of diverging stakeholder responses to environmental change
Authors: Newton Robert , Pfirman Stephanie , Schlosser Peter , Tremblay Bruno , Murray Maribeth , Pomerance Rafe
Published: July 2016

Recent trends and climate models suggest that the Arctic summer sea ice cover is likely to be lost before climate interventions can stabilize it. There are environmental, socioeconomic, and sociocultural arguments for, but also against, restoring and sustaining current conditions. Even if global warming can be reversed, some people will experience ice‐free summers before perennial sea ice begins to return. We ask: How will future generations feel about bringing sea ice back where they have not experienced it before? How will conflicted interests in ice‐covered vs. ice‐free conditions be resolved? What role will science play in these debates?
The First Documented Space Weather Event That Perturbed the Communication Networks in Iberia
Authors: Ribeiro P. , Vaquero J. M. , Gallego M. C. , Trigo R. M.
Published: July 2016

In this work, we review the first space weather event that affected significantly a number of communication networks in the Iberian Peninsula (Southwest of Europe). The event took place on 31 October 1903, during the ascending phase of solar cycle 14 (the lowest since the Dalton Minimum). We describe the widespread problems that occurred in the telegraph communication network in two midlatitude countries (Portugal and Spain), that was practically interrupted from 09 h30 to 21 h00 UT. Different impacts on the telegraphic communication are described and shown to be dependent on the large‐scale orientation of the wires. In order to put these results into a wider context we provide measurements of the concurrent geomagnetic field that are available from the observatories of Coimbra (Portugal) and San Fernando (Spain). The measurements confirm the simultaneous occurrence of large geomagnetic disturbances. In particular, the magnetograms recorded in Coimbra show a clear and large amplitude storm sudden commencement around 05 h30. The main phase, with a H (horizontal component of geomagnetic field) maximum range of ~500 nT, started approximately 1 h later and lasted for almost 10 h, suggesting that the interplanetary magnetic field was strongly southward for long time.
Metabolic Characteristics of 16HBE and A549 Cells Exposed to Different Surface Modified Gold Nanorods
Authors: Liu Zhigang , Wang Liming , Zhang Limin , Wu Xiaochun , Nie Guangjun , Chen Chunying , Tang Huiru , Wang Yulan
Published: July 2016

Gold nanorods (AuNRs) have shown their great potential in cancer treatment due to their special physiochemical and optical properties, and the ease of surface modification. However, the molecular mechanism of biological effects induced by different surface modified AuNRs remains largely undetermined. Herein, this study for the first time systematically analyzed metabolic impacts of three surface modified AuNRs in cancer and noncancer cells detected by NMR and GC‐FID/MS metabolomics and validated by molecular biological approach. It is found that positively and negatively charged AuNRs induce different metabolic consequences. Most importantly, it is found that the PEI‐AuNRs display specific cytotoxicity to A549 cells while posing little impact on 16HBE cells. The cytotoxicity of PEI‐AuNRs to A549 cells is manifested in large disruptions to the cell metabolisms, which affects energy metabolism, choline metabolism, the hexosamine biosynthesis pathway, and oxidative stress to cells. The results of this study provide comprehensive molecular information on the distinct biological effects of different surface modified AuNRs, and can be valuable in designing purpose‐driven nanomaterials. Most importantly, this work highlights the potential of metabolomics coupled with molecular biological techniques in screening antitumor nanodrugs and revealing the molecular mechanism of their biological effects.
Ultrathin Metal Films with Defined Topographical Structures as In Vitro Cell Culture Platforms for Unveiling Vascular Cell Behaviors
Authors: Jun Indong , Chung Yong‐Woo , Park Jimin , Han Hyung‐Seop , Park Jaeho , Kim Saeromi , Lee Hyunjung , Kim Sang Hoon , Han Jun‐Hyun , Kim Hyunjung , Seok Hyun‐Kwang , Kim Yu‐Chan , Jeon Hojeong
Published: July 2016

Implanted material surfaces make direct contact with body tissues to work on its own purpose. Therefore, studies of the surface properties of implantable materials that determine cell fate are very important for successful implantation. Although numerous studies have addressed the relationship between cells and material surfaces, nonmetallic surfaces and metallic surfaces likely produce different cellular responses because of their intrinsic differences in surface energy, roughness, and chemical composition. Moreover, given the nontransparent property of metal materials, which hampers the real‐time imaging of cellular behavior, a detailed cellular‐level analysis at the metal‐tissue interface has not been performed. In this study, metal‐based cell culture platforms (MCPs) with defined microscale topographical patterns are developed using a combination of photolithography and direct current magnetron sputtering techniques. The MCPs allow to observe vascular cells on metals in real time and identify the selective regulation of human aortic smooth muscle cells and Human umbilical vein endothelial cells (HUVECs) by metallic surface topography. Additionally, atomic force microscopy, contact angles, and energy‐dispersive X‐ray spectroscopy analyses show that the MCPs exhibit nearly identical chemical properties with their bulk counterparts, demonstrating that MCPs can be utilized as an in vitro cell culture platform system for understanding the cellular behavior on metal substrates.
Direct Synthesis of Water‐Soluble Aptamer‐Ag2S Quantum Dots at Ambient Temperature for Specific Imaging and Photothermal Therapy of Cancer
Authors: Gao Jingwen , Wu Chuanli , Deng Dan , Wu Ping , Cai Chenxin
Published: July 2016

Water‐soluble Ag2S near‐infrared (NIR) fluorescent quantum dots (QDs) are directly synthesized at ambient temperature for specific cancer imaging and photothermal therapy (PTT) using a designed aptamer (Apt43) as template, which consists of the following two fragments: an aptamer S2.2 sequence for specifically recognizing the cancer cells and an 18‐cytosine (18‐C) extending spacer for growing Ag2S QDs. The synthesized Ag2S QDs (Apt43‐Ag2S QDs), which exhibit strong absorption and fluorescence emission in the NIR region and high photothermal conversion capabilities, can specifically recognize MCF‐7 cells (human breast cancer cells) and are usable as a highly intensified imaging agent for cancer diagnosis. Moreover, they can be applied as photothermal agents for the in vitro killing of MCF‐7 cells and the in vivo ablation of tumors, which were constructed on the bodies of nude mice. MCF‐7 cells almost quantitatively die after they are incubated with the QDs (at 100 μg mL–1) for 2 h and irradiated under an 808 nm laser at a power density of 1.0 W cm–2 for 10 min. The tumors on the nude mice can also be effectively ablated without regrowth during the period of observation (at least 20 d) after PTT.
Supercontinuum Generation in Naturally Occurring Glass Sponges Spicules
Authors: Ehrlich Hermann , Maldonado Manuel , Parker Andrew R. , Kulchin Yuri N. , Schilling Jörg , Köhler Benjamin , Skrzypczak Ulrich , Simon Paul , Reiswig Henry M. , Tsurkan Mikhail V. , Brunner Eike , Voznesenskiy Sergey S. , Bezverbny Alexander V. , Golik Sergey S. , Nagorny Ivan G. , Vyalikh Denis V. , Makarova Anna A. , Molodtsov Serguei L. , Kummer Kurt , Mertig Michael , Erler Christiane , Kurek Denis V. , Bazhenov Vasilii V. , Natalio Filipe , Kovalev Alexander E. , Gorb Stanislav N. , Stelling Allison L. , Heitmann Johannes , Born René , Meyer Dirk C. , Tabachnick Konstantin R.
Published: July 2016

The complex process of supercontinuum generation (SG) is known to be exploitable for designing spatially coherent white light sources emitting light simultaneously in the ultraviolet, visible, and infrared ranges. Herein the first natural material able to generate in laboratory conditions a supercontinuum similar to those known from man‐made photonic crystal fibers is described. The ability resides in siliceous 20–50 cm long spicules of the glass sponge Sericolophus hawaiicus. By shedding into the spicules optical peak intensities ranging from 1 to 100 TW cm−2 the generation of a SG is revealed. The SG involves wavelengths between 650 and 900 nm and shows a maximum spectral spread for excitation at a wavelength of 750 nm. It is hypothesized that the SG is favored by spicules being a biocomposite that incorporates together isotopically pure biogenic silica (δ30Si = −3.28) and 15.2 ± 1.3 μg N‐acetyl‐glucosamine (chitin) per mg of silica. The internal organization of these spicules is distinguished by a solid silica core with a 1 μm wide axial channel as well as a highly ordered silica–chitin composite. Such a composition and organization pattern may be of potential interest for the design of low temperature synthesis of future materials for light guidance.
Nanoengineering Energy Conversion and Storage Devices via Atomic Layer Deposition
Authors: Wen Liaoyong , Zhou Min , Wang Chengliang , Mi Yan , Lei Yong
Published: July 2016

Nanostructured materials show a promising future in energy conversion and storage. However, different challenges shall be addressed to take the full advantages of nanomaterials, such as excess charge recombination sites yielded from large surface area and inefficient charge carrier separation because of poor material junctions in solar cells and solar water splitting cells, as well as high risk of surface side reactions and low active material density in batteries and supercapacitors. Considering its surface self‐limiting reaction mechanism, atomic layer deposition (ALD) enables the deposition of a thin film on high aspect ratio structures with a highly controllable manner (e.g., atomic accuracy and perfect conformity), which make it very suitable to overcome the key challenges associated with the size and dimension decrease of nanomaterials. In this review, the recent progress of the ALD application and processing in energy‐related devices is highlighted. Particular emphasis is placed on employing ALD for improving the device performance via synthesizing, modifying, or stabilizing their corresponding components. Finally, the challenges regarding the material synthesis and scalable manufacturing of the ALD technique are also discussed.
Power consumption and form drag of regular and fractal‐shaped turbines in a stirred tank
Authors: Steiros K. , Bruce P. J. K. , Buxton O. R. H. , Vassilicos J. C.
Published: July 2016

Previous wind‐tunnel measurements have shown that fractal‐shaped plates have increased drag compared to square plates of the same area. In this study, the power consumption and drag of turbines with fractal and rectangular blades in a stirred tank are measured. Power number decreases from rectangular to fractal impellers by over 10%, increasingly so with fractal iteration number. Our results suggest that this decrease is not caused by the wake interaction of the blades, nor solely by the wake interaction with the walls either. Pressure measurements on the blades’ surface show that fractal blades have lower drag than the rectangular ones, opposite to the wind tunnel experiment results. All tested blades’ center of pressure radius increases with Re, while their drag coefficient decreases, a possible effect of the solid body rotation expansion with Re. Spectral analysis of the pressure signal reveals two peaks possibly connected to the blades’ roll vortices. © 2016 American Institute of Chemical Engineers AIChE J, 63: 843–854, 2017
Sex difference in attractiveness perceptions of strong and weak male walkers
Authors: Fink Bernhard , André Selina , Mines Johanna S. , Weege Bettina , Shackelford Todd K. , Butovskaya Marina L.
Published: July 2016

Objectives

Men and women accurately assess male physical strength from facial and body morphology cues. Women's assessments of male facial attractiveness, masculinity, and dominance correlate positively with male physical strength. A positive relationship also has been reported between physical strength and attractiveness of men's dance movements. Here, we investigate men's and women's attractiveness, dominance, and strength assessments from brief samples of male gait.

Methods

Handgrip strength (HGS) was measured in 70 heterosexual men and their gait was motion‐captured. Men and women judged 20 precategorized strong (high HGS) and weak (low HGS) walkers on attractiveness, dominance, and strength, and provided a measure of their own HGS.

Results

Both men and women judged strong walkers higher on dominance and strength than weak walkers. Women but not men judged strong walkers more attractive than weak walkers. These effects were independent of observers' physical strength.

Conclusions

Male physical strength is conveyed not only through facial and body morphology, but also through body movements. We discuss our findings with reference to studies suggesting that physical strength provides information about male quality in contexts of inter‐ and intrasexual selection. Am. J. Hum. Biol. 28:913–917, 2016. © 2016Wiley Periodicals, Inc.
Immobilization of the Gas Signaling Molecule H2S by Radioisotopes: Detection, Quantification, and In Vivo Imaging
Authors: Sarkar Swarbhanu , Ha Yeong Su , Soni Nisarg , An Gwang Il , Lee Woonghee , Kim Min Hwan , Huynh Phuong Tu , Ahn Heesu , Bhatt Nikunj , Lee Yong Jin , Kim Jung Young , Park Kwon Moo , Ishii Isao , Kang Shin‐Geol , Yoo Jeongsoo
Published: July 2016

Hydrogen sulfide (H2S) has multifunctional roles as a gas signaling molecule in living systems. However, the efficient detection and imaging of H2S in live animals is very challenging. Herein, we report the first radioisotope‐based immobilization technique for the detection, quantification, and in vivo imaging of endogenous H2S. Macrocyclic 64Cu complexes that instantly reacted with gaseous H2S to form insoluble 64CuS in a highly sensitive and selective manner were prepared. The H2S concentration in biological samples was measured by a thin‐layer radiochromatography method. When 64Cu–cyclen was injected into mice, an elevated H2S concentration in the inflamed paw was clearly visualized and quantified by Cerenkov luminescence and positron emission tomography (PET) imaging. PET imaging was also able to pinpoint increased H2S levels in a millimeter‐sized infarcted lesion of the rat heart.
Total Synthesis of the Hamigerans
Authors: Li Xiaojun , Xue Dongsheng , Wang Cheng , Gao Shuanhu
Published: July 2016

The first total synthesis of hamigerans D, G, L, and N–Q has been accomplished. A convergent approach was used to build the basic tricarbocyclic ring system bearing a 5‐6‐6 structure. A sequence of oxidative cleavage, homologation, and ring regeneration provided access to the 5‐7‐6 skeleton of hamigeran G. Based on the biogenetic hypothesis, elegant and highly efficient biomimetic transformations of hamigeran G into hamigerans D, N–Q, and L were achieved.
Synthesis and Disassembly/Reassembly of Giant Ring‐Shaped Polyoxotungstate Oligomers
Authors: Minato Takuo , Suzuki Kosuke , Yamaguchi Kazuya , Mizuno Noritaka
Published: July 2016

The disassembly and reassembly of giant molecules are essential processes in controlling the structure and function of biological and artificial systems. In this work, the disassembly and reassembly of a giant ring‐shaped polyoxometalate (POM) without isomerization of the monomeric units is reported. The reaction of a hexavacant lacunary POM that is soluble in organic solvents, [P2W12O48]14−, with manganese cations gave the giant ring‐shaped POM [{γ‐P2W12O48Mn4(C5H7O2)2(CH3CO2)}6]42−. This POM is a hexamer of manganese‐substituted {P2W12O48Mn4} units, and its inner cavity was larger than any of those previously reported for ring‐shaped polyoxotungstates. It was disassembled into monomeric units in acetonitrile, and the removal of the capping organic ligands on the manganese cations led to reassembly into a tetrameric ring‐shaped POM, [{γ‐P2W12O48Mn4(H2O)6}4(H2O)4]24−.
Lewis Acid Catalyzed Selective Reactions of Donor–Acceptor Cyclopropanes with 2‐Naphthols
Authors: Kaicharla Trinadh , Roy Tony , Thangaraj Manikandan , Gonnade Rajesh G. , Biju Akkattu T.
Published: July 2016

Lewis acid‐catalyzed reactions of 2‐substituted cyclopropane 1,1‐dicarboxylates with 2‐naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)3 as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene‐fused cyclopentanes. Interestingly, engaging Sc(OTf)3 as the Lewis acid, a Friedel–Crafts‐type addition of 2‐naphthols to cyclopropanes takes place, thus affording functionalized 2‐naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields.
Sequenz‐spezifischer Einbau von Enzym‐Nukleotid‐Chimären durch DNA‐Polymerasen
Authors: Welter Moritz , Verga Daniela , Marx Andreas
Published: July 2016

Durch Erkennung von Form und Geometrie des naszierenden Nukleotidpaars stellen DNA‐Polymerasen die hohe Selektivität der DNA‐Replikation sicher. Man geht davon aus, dass DNA‐Polymerasen mit hoher Replikationsgenauigkeit hierzu ein genau angepasstes aktives Zentrum enthalten, das nur geringe Abweichungen von den kanonischen Basenpaarungen toleriert. Dennoch ist bekannt, dass DNA‐Polymerasen Nukleotide mit kleinen Modifikationen als Substrate akzeptieren, was von wesentlicher Bedeutung für zahlreiche grundlegende biotechnologische Anwendungen ist. Hier wird nun gezeigt, dass selbst DNA‐Polymerasen, die eine hohe Replikationsgenauigkeit aufweisen, in der Lage sind, eine Nukleotid‐Chimäre, die mit einem großen Protein wie der Meerrettichperoxidase modifiziert ist, als Substrat zu nutzen, obwohl diese “Fracht” um ein Hundertfaches größer ist als das natürliche Substrat. Wir nutzten diese Eigenschaft, um ein Testsystem zu entwickeln, das den Nachweis von DNA und RNA in Einzelbasenauflösung mit bloßem Auge ermöglicht.
Kontrolle der Kinetik von Iminaustauschreaktionen mit Photoschaltern zur lichtgesteuerten Modulation der Selbstheilung in Polysiloxannetzwerken
Authors: Kathan Michael , Kovaříček Petr , Jurissek Christoph , Senf Antti , Dallmann Andre , Thünemann Andreas F. , Hecht Stefan
Published: July 2016

Es wurden mehrere aldehydsubstituierte Photoschalter entwickelt, deren Reaktivität gegenüber Aminen ferngesteuert werden kann. Ein thermisch stabiles, difunktionelles Diarylethen, das in seiner ringgeschlossenen Form eine um den Faktor zehn erhöhte Reaktivität gegenüber Aminen aufweist, wurde als photoschaltbarer Vernetzer für ein kommerziell erhältliches, aminofunktionalisiertes Polysiloxan eingesetzt. Die Selbstheilungsgeschwindigkeit und viskoelastischen Eigenschaften dieses gummiartigen Materials können somit reversibel mit Licht moduliert werden.
Catalytic Asymmetric Synthesis of Cyclopentyl β‐Amino Esters by [3+2] Cycloaddition of Enecarbamates with Electrophilic Metalloenolcarbene Intermediates
Authors: Deng Yongming , Yglesias Matthew V. , Arman Hadi , Doyle Michael P.
Published: July 2016

Chiral cyclopentyl β‐amino esters are formed catalytically by [3+2] cycloaddition reactions of enecarbamates with electrophilic metalloenolcarbenes in high yield with up to 98 % ee and excellent diastereocontrol. Use of β‐silyl‐substituted enoldiazoacetates with a chiral dirhodium catalyst and trans‐β‐arylvinylcarbamates are optimal for this transformation, which occurs with hydrogen‐bond association between the vinylcarbamate and the intermediate metalloenolcarbene. Reductive conversion of the protected amino esters forms highly functionalized cyclopentyl β‐amino acids and 3‐aminocyclopentanones.
Combining Neopentyllithium with Potassium tert‐Butoxide: Formation of an Alkane‐Soluble Lochmann–Schlosser Superbase
Authors: Benrath Philipp , Kaiser Maximilian , Limbach Thomas , Mondeshki Mihail , Klett Jan
Published: July 2016

Mixtures of alkyllithium and heavier alkali‐metal alkoxides are often used to form alkyl compounds of heavier alkali metals, but these mixtures are also known for their high reactivity in deprotonative metalation reactions. These organometallic mixtures are often called LiC–KOR superbases, but despite many efforts their constitution remains unknown. Herein we present mixed alkali‐metal alkyl/alkoxy compounds produced by reaction of neopentyllithium with potassium tert‐butoxide. The key to success was the good solubility and temperature‐stability of neopentyl alkali‐metal compounds, leading to hexane‐soluble mixtures, which allowed handling at ambient temperatures and isolation by crystallization. The compounds in solid state and in solution were identified by X‐ray crystallography and NMR spectroscopy as mixtures of lithium/potassium neopentyl/tert‐butoxy aggregates of varying compositions LixKyNpz(OtBu)x+y−z.
Unveiling (−)‐Englerin A as a Modulator of L‐Type Calcium Channels
Authors: Rodrigues Tiago , Sieglitz Florian , Somovilla Víctor J. , Cal Pedro M. S. D. , Galione Antony , Corzana Francisco , Bernardes Gonçalo J. L.
Published: July 2016

The voltage‐dependent L‐type Ca2+channel was identified as a macromolecular target for (−)‐englerin A. This finding was reached by using an unprecedented ligand‐based prediction platform and the natural product piperlongumine as a pharmacophore probe. (−)‐Englerin A features high substructure dissimilarity to known ligands for voltage‐dependent Ca2+ channels, selective binding affinity for the dihydropyridine site, and potent modulation of calcium signaling in muscle cells and vascular tissue. The observed activity was rationalized at the atomic level by molecular dynamics simulations. Experimental confirmation of this hitherto unknown macromolecular target expands the bioactivity space for this natural product and corroborates the effectiveness of chemocentric computational methods for prioritizing target‐based screens and identifying binding counterparts of complex natural products.
Deformylation Reaction by a Nonheme Manganese(III)–Peroxo Complex via Initial Hydrogen‐Atom Abstraction
Authors: Barman Prasenjit , Upadhyay Pranav , Faponle Abayomi S. , Kumar Jitendra , Nag Sayanta Sekhar , Kumar Devesh , Sastri Chivukula V. , de Visser Sam P.
Published: July 2016

Metal–peroxo intermediates are key species in the catalytic cycles of nonheme metalloenzymes, but their chemical properties and reactivity patterns are still poorly understood. The synthesis and characterization of a manganese(III)–peroxo complex with a pentadentate bispidine ligand system and its reactivity with aldehydes was studied. Manganese(III)–peroxo can react through hydrogen‐atom abstraction reactions instead of the commonly proposed nucleophilic addition reaction. Evidence of the mechanism comes from experiments which identify a primary kinetic isotope effect of 5.4 for the deformylation reaction. Computational modeling supports the established mechanism and identifies the origin of the reactivity preference of hydrogen‐atom abstraction over nucleophilic addition.
MgI2‐chemoselective cleavage for removal of amino acid protecting groups: A fresh vision for peptide synthesis
Authors: Berthet Mathéo , Martinez Jean , Parrot Isabelle
Published: July 2016

In the field of peptide synthesis, the key to a successful access to synthetic targets lies on a pertinent combination of protecting groups. Their choice is directed by their selective removal conditions. We present here the behavior of some of the most used protecting groups in peptide chemistry under experimental cleavage conditions, combining MgI2 with MW irradiation, using 2‐Me‐THF as a green solvent. In these experimental conditions, the benzyloxycarbonyl protecting group as well as the Merrifield resin can be re‐considered in peptide chemistry.
In vitro metabolism of specific CYP2D and CYP3A opioid substrates using rat liver S9 fractions and mass spectrometry reveal a severe metabolic impairment with increasing age
Authors: Salmin Sabrin Fuad , Giroux Marie‐Chantal , Vachon Pascal , Beaudry Francis
Published: July 2016

Codeine and oxycodone are opioids used to alleviate pain. The outcome of the treatment is ultimately related to their metabolism by Cytochromes P450 (CYPs). Depending on the drugs used, alterations in the metabolism of drugs by CYPs can lead to severe consequences including alterations in their efficacy, safety and toxicity. The objectives of this study were to develop a novel HPLC–MS/MS method capable of quantifying codeine and oxycodone along with specific metabolites using an isotopic dilution strategy and study the rate of formation of morphine (CYP2D), norcodeine (CYP3A), oxymorphone (CYP2D) and noroxycodone (CYP3A). The chromatographic separation was achieved using a Biobasic C18 100 × 1 mm column combined with an isocratic mobile phase composed of methanol and 10 mm ammonium acetate (40:60) at a flow rate of 75 μL/min. The mass spectrometer was operating in scan mode MS/MS and the analytical range was set at 10–10 000 nm. The precision (RSD) and accuracy (RE) observed were 4.4–11.5 and −9.1–6.1% respectively. Liver S9 fractions from 3‐, 6‐, 12‐ and 18‐month‐old male Sprague–Dawley rats were prepared and Michaelis–Menten parameters were determined. The derived maximum enzyme velocity suggested a rapid saturation of the CYP2D and CYP3A active sites in the liver S9 fractions of 18‐month‐old rats. Moreover, metabolic stabilities of codeine and oxycodone in rat liver S9 fractions were significantly greater for the 18‐month‐old rats. This study suggests that there is an impairment of CYP2D and CYP3A metabolism in aging rats.
Exploring the capabilities of fluorometric online monitoring on chinese hamster ovary cell cultivations producing a monoclonal antibody
Authors: Schwab Karen , Amann Thomas , Schmid Jakob , Handrick René , Hesse Friedemann
Published: July 2016

Online monitoring of Chinese hamster ovary fed‐batch cell cultures via two‐dimensional fluorescence spectroscopy (2DFS) was evaluated in this work. Particular attention was directed toward different process strategies regarding the use of nutrient‐rich feed media and temperature shifts. These intentionally performed process manipulations broadened the variances in the obtained fluorescence spectra and this was suspected to hamper the generation of reliable soft sensors. Principal component analysis of the obtained fluorescence data showed that temperature shift and feeding strategy had a considerable impact on the fluorescence signals. Partial least square regression models were calculated for the prediction of glucose, lactate, monoclonal antibody (mAb), and viable cell concentrations (VCC). It was aimed to integrate all 2DFS datasets in the respective calibration models regardless of the process‐strategy‐dependent diversity. Contrary to the expectations, it was feasible to calibrate soft sensors for the online prediction of glucose (7 latent variables (LVs),
 = 0.97, rout mean squared error of prediction (RMSEP) = 1.1 g L−1), lactate (5 LV;
 = 0.96; RMSEP = 0.5 g L−1) and mAb concentrations (4 LV;
 = 0.99; RMSEP = 11.4 mg L−1). Feeding and temperature shifts had the highest impact on the VCC model (3 LV;
 = 0.94; RMSEP 3.8 × 105 mL−1), nevertheless the prediction of VCC from the fed‐batch 2DFS data was feasible. The results strongly indicate that variances in the datasets due to the process strategy can be tolerated to some extent by the respective soft sensors. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1592–1600, 2016
Enzymatic Resolution by a d‐Lactate Oxidase Catalyzed Reaction for (S)‐2‐Hydroxycarboxylic Acids
Authors: Sheng Binbin , Xu Jing , Ge Yongsheng , Zhang Shuo , Wang Danqi , Gao Chao , Ma Cuiqing , Xu Ping
Published: July 2016

Oxidase‐catalyzed kinetic resolution is important for the production of enantiopure 2‐hydroxycarboxylic acids (2‐HAs), which are versatile building blocks for the synthesis of many significant compounds. However, in contrast to that of (R)‐2‐HAs, the production of (S)‐2‐HA is challenging because of the lack of related oxidases. Herein, suitable enzymes were screened systematically through the analysis of numerous putative d‐lactate oxidase sequences and identification of several required properties. Finally, a d‐lactate oxidase from Gluconobacter oxydans 621H with advantageous characteristics, such as good solubility, broad substrate spectrum, and high stereoselectivity, was selected to resolve 2‐HAs into (S)‐2‐HAs. A variety of (S)‐2‐HAs was produced successfully using this d‐lactate oxidase with excellent enantiomeric excess values (>99 %). The presented screening criteria and approach for target biocatalysis suggested a guideline for the production of optically active chemicals such as (S)‐2‐HAs.
Functionalization of Pyrene To Prepare Luminescent Materials—Typical Examples of Synthetic Methodology
Authors: Feng Xing , Hu Jian‐Yong , Redshaw Carl , Yamato Takehiko
Published: July 2016

Pyrene‐based π‐conjugated materials are considered to be an ideal organic electro‐luminescence material for application in semiconductor devices, such as organic light‐emitting diodes (OLEDs), organic field‐effect transistors (OFETs) and organic photovoltaics (OPVs), and so forth. However, the great drawback of employing pyrene as an organic luminescence material is the formation of excimer emission, which quenches the efficiency at high concentration or in the solid‐state. Thus, in order to obtain highly efficient optical devices, scientists have devoted much effort to tuning the structure of pyrene derivatives in order to realize exploitable properties by employing two strategies, 1) introducing a variety of moieties at the pyrene core, and 2) exploring effective and convenient synthetic strategies to functionalize the pyrene core. Over the past decades, our group has mainly focused on synthetic methodologies for functionalization of the pyrene core; we have found that formylation/acetylation or bromination of pyrene can selectly lead to functionalization at K‐region by Lewis acid catalysis. Herein, this Minireview highlights the direct synthetic approaches (such as formylation, bromination, oxidation, and de‐tert‐butylation reactions, etc.) to functionalize the pyrene in order to advance research on luminescent materials for organic electronic applications. Further, this article demonstrates that the future direction of pyrene chemistry is asymmetric functionalization of pyrene for organic semiconductor applications and highlights some of the classical asymmetric pyrenes, as well as the latest breakthroughs. In addition, the photophysical properties of pyrene‐based molecules are briefly reviewed. To give a current overview of the development of pyrene chemistry, the review selectively covers some of the latest reports and concepts from the period covering late 2011 to the present day.
Regioselective, Solvent‐ and Metal‐Free Chalcogenation of Imidazo[1,2‐a]pyridines by Employing I2/DMSO as the Catalytic Oxidation System
Authors: Rafique Jamal , Saba Sumbal , Rosário Alisson R. , Braga Antonio L.
Published: July 2016

Highly efficient molecular‐iodine‐catalyzed chalcogenations (S and Se) of imidazo[1,2‐a]pyridines were achieved by using diorganoyl dichalcogenides under solvent‐free conditions. This approach afforded the desired products that had been chalcogenated regioselectively at the C3 position in up to 96 % yield by using DMSO as an oxidant, in the absence of a metal catalyst, and under an inert atmosphere. This mild, green approach allowed the preparation of different types of chalcogenated imidazo[1,2‐a]pyridines with structural diversity. Furthermore, the current protocol was also extended to other N‐heterocyclic cores.
New Found Hope for Antibiotic Discovery: Lipid II Inhibitors
Authors: Ng Vivian , Chan Weng C.
Published: July 2016

Research into antibacterial agents has recently gathered pace in light of the disturbing crisis of antimicrobial resistance. The development of modern tools offers the opportunity of reviving the fallen era of antibacterial discovery through uncovering novel lead compounds that target vital bacterial cell components, such as lipid II. This paper provides a summary of the role of lipid II as well as an overview and insight into the structural features of macrocyclic peptides that inhibit this bacterial cell wall component. The recent discovery of teixobactin, a new class of lipid II inhibitor has generated substantial research interests. As such, the significant progress that has been achieved towards its development as a promising antibacterial agent is discussed.
An Unprecedented Two‐Fold Nested Super‐Polyrotaxane: Sulfate‐Directed Hierarchical Polythreading Assembly of Uranyl Polyrotaxane Moieties
Authors: Mei Lei , Wu Qun‐yan , Yuan Li‐yong , Wang Lin , An Shu‐wen , Xie Zhen‐ni , Hu Kong‐qiu , Chai Zhi‐fang , Burns Peter C. , Shi Wei‐qun
Published: July 2016

The hierarchical assembly of well‐organized submoieties could lead to more complicated superstructures with intriguing properties. We describe herein an unprecedented polyrotaxane polythreading framework containing a two‐fold nested super‐polyrotaxane substructure, which was synthesized through a uranyl‐directed hierarchical polythreading assembly of one‐dimensional polyrotaxane chains and two‐dimensional polyrotaxane networks. This special assembly mode actually affords a new way of supramolecular chemistry instead of covalently linked bulky stoppers to construct stable interlocked rotaxane moieties. An investigation of the synthesis condition shows that sulfate can assume a vital role in mediating the formation of different uranyl species, especially the unique trinuclear uranyl moiety [(UO2)3O(OH)2]2+, involving a notable bent [O=U=O] bond with a bond angle of 172.0(9)°. Detailed analysis of the coordination features, the thermal stability as well as a fluorescence, and electrochemical characterization demonstrate that the uniqueness of this super‐polyrotaxane structure is mainly closely related to the trinuclear uranyl moiety, which is confirmed by quantum chemical calculations.
The Effect of KOH Treatment on the Chemical Structure and Electrocatalytic Activity of Reduced Graphene Oxide Materials
Authors: Kim Sujin , Choi Kwangrok , Shim Yeonjun , Lee Seungjun , Park Sungjin
Published: July 2016

Reduced graphene oxide (rG‐O)‐based materials have great potential as metal‐free electrocatalysts for the oxygen reduction reaction (ORR) owing to their electrical and electrochemical properties and large surface area. Long‐term durability and chemical stability of the catalysts in the presence of electrolytes such as aqueous KOH solution are important for their use in practical applications. In this study, three types of rG‐O and rG‐O‐K (rG‐O after reaction with KOH) materials were synthesized. The chemical structures, surface areas, and catalytic ORR performances of the rG‐O materials were compared with those of the corresponding rG‐O‐K materials. The onset potentials of the rG‐O materials for electrocatalytic reduction of oxygen are almost the same as those of the corresponding rG‐O‐K materials; however, the current density and the number of transferred electrons are significantly reduced. These data show that the catalytic ORR performance of rG‐O‐based materials can be altered by KOH.