bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lichtinduzierte Wasseroxidation durch ein molekulares Manganvanadiumoxid
Authors: Schwarz Benjamin , Forster Johannes , Goetz McKenna K. , Yücel Duygu , Berger Claudia , Jacob Timo , Streb Carsten 
Published: April 2016

AbstractIn der Natur findet die photosynthetische Wasseroxidation an einem anorganischen Calcium‐Mangan‐Oxo‐Komplex (Oxygen‐Evolving Complex, OEC) im Photosystem II statt. Hier berichten wir über ein synthetisches Modell des OEC auf Basis eines molekularen Manganvanadiumoxids: [Mn4V4O17(OAc)3]3−. Dessen Herzstück ist ein [Mn4O4]6+‐Kubus, der die homogene, lichtgetriebene Oxidation von Wasser zu Sauerstoff katalysiert. Der zentrale Kubus wird durch ein tripodales Polyoxovanadat, [V4O13]6−, sowie drei Acetatliganden stabilisiert. In Kombination mit der Lichtsammeleinheit [Ru(bpy)3]2+ und dem Elektronenakzeptor S2O82− erfolgt die lichtgetriebene Wasseroxidation mit Umsatzzahlen von ca. 1150 und Umsatzfrequenzen von ca. 1.75 s−1. Elektrochemische, massenspektrometrische sowie spektroskopische Untersuchungen geben einen Einblick in die Stabilität und Reaktivität des Manganvanadiumoxids. Dieses könnte als Modellsystem für die Struktur und Reaktivität des OEC sowie für heterogene Wasseroxidationskatalysatoren fungieren.
Plastic Antibodies for Cosmetics: Molecularly Imprinted Polymers Scavenge Precursors of Malodors
Authors: Nestora Sofia , Merlier Franck , Beyazit Selim , Prost Elise , Duma Luminita , Baril Bérangère , Greaves Andrew , Haupt Karsten , Tse Sum Bui Bernadette 
Published: April 2016

AbstractMolecularly imprinted polymers (MIPs) are synthetic antibody mimics capable of specific molecular recognition. Advantageously, they are more stable, easy to tailor for a given application and less expensive than antibodies. These plastic antibodies are raising increasing interest and one relatively unexplored domain in which they could outplay these advantages particularly well is cosmetics. Here, we present the use of a MIP as an active ingredient of a cosmetic product, for suppressing body odors. In a dermo‐cosmetic formulation, the MIP captures selectively the precursors of malodorous compounds, amidst a multitude of other molecules present in human sweat. These results pave the way to the fabrication of a novel generation of MIPs with improved selectivities in highly complex aqueous environments, and should be applicable to biotechnological and biomedical areas as well.
Palladium‐Catalyzed Oxidative Synthesis of α‐Acetoxylated Enones from Alkynes
Authors: Jiang Tuo , Quan Xu , Zhu Can , Andersson Pher G. , Bäckvall Jan‐E. 
Published: April 2016

AbstractWe report a palladium‐catalyzed oxidative functionalization of alkynes to generate α‐acetoxylated enones in one step. A range of functional groups are well‐tolerated in this reaction. Mechanistic studies, including the use of 18O‐labeled DMSO, revealed that the ketone oxygen atom in the product originates from DMSO.
An Elastic Monolithic Catalyst: A Microporous Metalloporphyrin‐Containing Framework‐Wrapped Melamine Foam for Process‐Intensified Acyl Transfer
Authors: Wu Keyi , Guo Jia , Wang Changchun 
Published: April 2016

AbstractThe advent of conjugated microporous polymers (CMPs) has had significant impact in catalysis. However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of CMPs in catalytic reactions. Herein, the preparation of a foam‐supporting CMP composite with interconnective micropores and macropores and elastic properties is reported. Metalloporphyrin‐based CMP organogels are synthesized within the melamine foam by a room‐temperature oxidative homocoupling reaction of terminal alkynes. Upon drying, the CMP‐based xerogels tightly wrap the framework skeletons of the foam, while the foam cells are still open to allow for the preservation of elasticity and macroporosity. Such a hierarchical structure is efficient for acyl transfer, facilitates substrate diffusion within interpenetrative macropores and micropores, and could be used to intensify catalytic processes.
Allosteric Optical Control of a Class B G‐Protein‐Coupled Receptor
Authors: Broichhagen Johannes , Johnston Natalie R. , von Ohlen Yorrick , Meyer‐Berg Helena , Jones Ben J. , Bloom Stephen R. , Rutter Guy A. , Trauner Dirk , Hodson David J. 
Published: April 2016

AbstractAllosteric regulation promises to open up new therapeutic avenues by increasing drug specificity at G‐protein‐coupled receptors (GPCRs). However, drug discovery efforts are at present hampered by an inability to precisely control the allosteric site. Herein, we describe the design, synthesis, and testing of PhotoETP, a light‐activated positive allosteric modulator of the glucagon‐like peptide‐1 receptor (GLP‐1R), a class B GPCR involved in the maintenance of glucose homeostasis in humans. PhotoETP potentiates Ca2+, cAMP, and insulin responses to glucagon‐like peptide‐1 and its metabolites following illumination of cells with blue light. PhotoETP thus provides a blueprint for the production of small‐molecule class B GPCR allosteric photoswitches, and may represent a useful tool for understanding positive cooperativity at the GLP‐1R.
Bimetallic Gold(I)/Chiral N,N′‐Dioxide Nickel(II) Asymmetric Relay Catalysis: Chemo‐ and Enantioselective Synthesis of Spiroketals and Spiroaminals
Authors: Li Jun , Lin Lili , Hu Bowen , Lian Xiangjin , Wang Gang , Liu Xiaohua , Feng Xiaoming 
Published: April 2016

AbstractA highly efficient asymmetric cascade reaction between keto esters and alkynyl alcohols and amides is reported. The success of the reaction was attributed to the combination of chiral Lewis acid N,N′‐dioxide nickel(II) catalysis with achiral π‐acid gold(I) catalysis working as an asymmetric relay catalytic system. The corresponding spiroketals and spiroaminals were synthesized in up to 99 % yield, 19:1 d.r., and more than 99 % ee under mild reaction conditions. Control experiments suggest that the N,N′‐dioxide ligand was essential for the formation of the spiro products.
Heat‐Flow‐Driven Oligonucleotide Gelation Separates Single‐Base Differences
Authors: Morasch Matthias , Braun Dieter , Mast Christof B. 
Published: April 2016

AbstractDNA phase transitions are often induced by the addition of condensation agents or by dry concentration. Herein, we show that the non‐equilibrium setting of a moderate heat flow across a water‐filled chamber separates and gelates DNA strands with single‐base resolution. A dilute mix of DNA with two slightly different gel‐forming sequences separates into sequence‐pure hydrogels under constant physiological solvent conditions. A single base change in a 36 mer DNA inhibits gelation. Only sequences with the ability to form longer strands are concentrated, further elongated, and finally gelated by length‐dependent thermal trapping. No condensation agents, such as multivalent ions, were added. Equilibrium aggregates from dry concentration did not show any sequence separation. RNA is expected to behave identically owing to its equal thermophoretic properties. The highly sequence‐specific phase transition points towards new possibilities for non‐equilibrium origins of life.
Novel amino acid‐based ionic liquid analogues: neutral hydroxylic and sulfur‐containing amino acids
Authors: Mjalli Farouq S. , Al‐Hajri Rashid , Al‐Muhtaseb Ala'a , Ahmed Omar , Nagaraju Maddela 
Published: April 2016

AbstractDeep eutectic solvents (DESs) have shown potential promise for various industrial applications. Abundant research works were carried out on Type III DES employing choline chloride as the quaternary ammonium salt in combination with a variety of hydrogen bond donors (HBDs). Despite the fact that they are cheap, biodegradable, and have a wide application in food, polymer, and pharmaceutical industries, amino acids have not been utilized as HBD for the synthesis of DES. In this work, different ammonium‐based salts are used to synthesize different amino acid‐based DES systems. Four different amino acids are considered, two of which are neutral amino acids, namely L‐serine and L‐threonine, while the other two are based on the sulfur‐containing amino acids, namely L‐methionine and L‐cysteine. The successful DESs were characterized in terms of their physical properties. The melting point, density, viscosity, surface tension, refractive index, conductivity, and pH were measured for the successful DES systems at different temperatures ranging from 303.15 to 353.15 K. The introduction of such novel DES opens the door for performing more work on utilizing them for various chemical, biochemical, and pharmaceutical applications. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.
Acid−base properties of polyethylene composites with clays
Authors: Kraus Eduard , Nguen Duk‐Ahn , Efimova Alfia , Starostina Irina , Stoyanov Oleg 
Published: April 2016

ABSTRACTWe report on the surface energy characteristics of composite materials based on low‐density polyethylene with addition of bentonite and organic clay. Investigated were the surface free energy, its components and parameters by wetting methods according to Berger, spatial method, and method of nonlinear systems. The determined characteristics were carried out by the selective wetting conditions for the individual constituents of the composition, including the clay powder. The thermal, mechanical, and morphological properties of obtained composites were investigated. The possibility for predicting the surface properties of composite materials based on component‐wise analysis was demonstrated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43629.
Structure, thermal stability, electrochemical behaviors, and mechanical properties of organosoluble polyimide with pyrimidine ring in the main chain
Authors: Li Baoming , Wu Zhiyin , Lin Li 
Published: April 2016

ABSTRACTA novel organosoluble polyimide (PI) with pyrimidine ring in the main chain was synthesized by chemical and thermal imidization, respectively, from 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 2,4‐diamino‐6‐chloropyrimidine as raw materials and its molecular structure, solubility, UV–visible absorption characteristic, crystallinity, thermal stability, electrochemical behaviors, and mechanical properties were also studied. It was found that the introduction of pyrimidine ring in the main chain could increase the solubility of PI in polar aprotic solvents at room temperature and 60 °C, respectively, because of its molecular main chain with asymmetric structure and two polar N atoms in pyrimidine ring. Furthermore, PI had strong optical absorption peak intensity, excellent thermal stability, good redox reversibility, especially outstanding mechanical properties, which were conductive to its potential applications in adhesives, polyelectrolyte, separation membrane, and so on. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43680.
Preparation of nonwoven mats of electrospun poly(lactic acid)/polyaniline blend nanofibers: A new approach
Authors: Al‐Jallad Mazen , Atassi Yomen 
Published: April 2016

ABSTRACTThe preparation of nonwoven mats of electrospun poly(lactic acid)/polyaniline (PANI) blend nanofibers faces some critical challenges that will be addressed in the present work. The challenges are in achieving high and adjustable content of PANI while keeping the spinnable solution nonagglomerated with no need to further filtration that might lead to wrong estimation of PANI content in the mat. We report an unprecedented content of 40% wt of PANI that is achieved using a new two‐step procedure. It is based on: (1) the preparation of the spinnable solution from a friable nonagglomerated and readily dispersible PANI:
‐TSA powder and (2) the use of an optimized mixture of
‐cresol/dichloromethane. The obtained nanofiber mats are characterized by FTIR and UV–vis spectroscopy. The morphology and the thermal stability of the nanofibers are investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The amorphous structure of the nanofibers is verified using XRD measurements. The DC‐conductivity of these blend nanofibers is found to be far larger than the published DC‐conductivity values for blend nanofibers of PANI with PLLA or with other polymers. This is attributed to the high content of PANI in the blend and to the role played by
‐cresol as a secondary dopant. The investigation of the aging effect on the DC‐conductivity reveals an exponential decrease with a characteristic time of
weeks. The electrical impedance spectroscopy (EIS) shows a pure ohmic behavior of the blend mat. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43687.
Comparison of antimicrobial activities of polyacrylonitrile fibers modified with quaternary phosphonium salts having different alkyl chain lengths
Authors: Chang Li , Wang Jing , Tong Chunyi , Zhao Liang , Liu Xuanming 
Published: April 2016

ABSTRACTA series of polyacrylonitrile fibers (PANF) modified with quaternary phosphonium salts having various alkyl chain lengths (C1, C2, C6, C8, C12) were synthesized and compared for their antimicrobial activities by the improved shake flask method. The as‐prepared fibers were named MTPB‐PANF, ETPB‐PANF, HTPB‐PANF, OTPB‐PANF, and DTPB‐PANF, respectively. The representative microorganisms employed were Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans). Results from the current study showed that the alkyl chain length of quaternary phosphonium salts not only affected the synthesis of the fibers, but also impacted their antimicrobial activities. There was a rule that the longer the alkyl chain length, the more easily the quaternary phosphonium salts modify the fibers and the better the antimicrobial activities of the modified fibers. All the modified fibers exhibited good broad‐spectrum antimicrobial activities. Specifically, DTPB‐PANF exhibited an outstandingly high antimicrobial activity, which was nearly unaffected by the environmental pH (3–10). It can kill all the four pathogens in 15 min and had an excellent wash‐resistant property. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43689.
Characterization and mechanical property of Trinidad coir fibers
Authors: Mathura Nadira , Cree Duncan 
Published: April 2016

ABSTRACTCoir fibers were retted in distilled water (DW) and saline water (SW) for up to 12 weeks. Fibers had diameters of 0.16 mm to 0.56 mm, gauge lengths (GL) of 20 mm and 50 mm, and loaded at strain rates of 5, 20, 40, and 60 mm/min. Tensile strength, Young's modulus, and strain at break properties were evaluated and the results statistically analyzed using analysis of variance (ANOVA). For non‐retted fibers, as the gauge length decreased, the tensile and strain at break increased by 14% and 42%, respectively, while the stiffness increased by 33% for larger gauge lengths. As the fiber diameter decreased, the tensile strength increased from 48.45 MPa to 134.41 MPa for 50 mm gauge length fibers. X‐ray diffraction (XRD) was used to calculate the crystallinity index (CI) of the coir fibers. Secondary electron microscopy was used to assess the fiber surface and fractured area. Although the chemical composition was different, the properties of Trinidad coir fibers were in‐line with coir fibers from other parts of the world making them an ideal material of choice for composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43692.
The Efficacy and Safety of Clazakizumab, an Anti–Interleukin‐6 Monoclonal Antibody, in a Phase IIb Study of Adults With Active Psoriatic Arthritis
Authors: Mease Philip J. , Gottlieb Alice B. , Berman Alberto , Drescher Edit , Xing Jun , Wong Robert , Banerjee Subhashis 
Published: April 2016

ObjectiveTo evaluate the efficacy of clazakizumab, a monoclonal antibody with high affinity and specificity for the interleukin‐6 (IL‐6) cytokine, in psoriatic arthritis (PsA).MethodsIn this randomized, double‐blind, placebo‐controlled, dose‐ranging study (ClinicalTrials. gov identifier: NCT01490450), patients with active PsA and an inadequate response to nonsteroidal antiinflammatory drugs were randomized (1:1:1:1) to receive subcutaneous placebo or clazakizumab 25 mg, 100 mg, or 200 mg every 4 weeks, with or without methotrexate. The primary end point was the response rate according to the American College of Rheumatology 20% criteria for improvement (ACR20) at week 16, with secondary efficacy end points at weeks 16 and 24.ResultsA total of 165 patients were randomized. At week 16, the ACR20 response rate was significantly higher with clazakizumab 100 mg versus placebo (52.4% versus 29.3%; P = 0.039). ACR20 response rates at week 16 were 46.3% with clazakizumab 25 mg (P = 0.101 versus placebo) and 39.0% with clazakizumab 200 mg (P = 0.178 versus placebo). ACR50/ACR70 response rates were numerically higher with clazakizumab versus placebo at weeks 16 and 24. Compared with placebo, clazakizumab treatment significantly improved musculoskeletal manifestations (joint signs and symptoms, enthesitis, and dactylitis), with minimal improvements in skin disease, without clear evidence of a dose response. Clazakizumab was well tolerated.ConclusionThis is the first clinical trial of an IL‐6–targeted therapy in PsA. Clazakizumab may be an effective treatment option for musculoskeletal aspects of PsA, but because of the lack of a dose response in this study, further studies are required to confirm the appropriate dose. The safety profile is consistent with the pharmacology of IL‐6 blockade and prior clinical experience with this antibody in rheumatoid arthritis.
Autoantibody‐Positive Healthy Individuals Display Unique Immune Profiles That May Regulate Autoimmunity
Authors: Slight‐Webb Samantha , Lu Rufei , Ritterhouse Lauren L. , Munroe Melissa E. , Maecker Holden T. , Fathman Charles G. , Utz Paul J. , Merrill Joan T. , Guthridge Joel M. , James Judith A. 
Published: April 2016

ObjectiveAntinuclear antibodies (ANAs) are detected in ∼18% of females, yet autoimmune disease develops in only 5–8%. Immunologic differences between ANA‐positive healthy individuals and patients with systemic lupus erythematosus (SLE) may elucidate the regulatory mechanisms by which ANA‐positive individuals avoid transition to clinical autoimmune disease.MethodsHealthy individuals (n = 790) were screened for autoantibodies specific for 11 antigens associated with lupus, systemic sclerosis, and Sjögren's syndrome. From this screening, 31 European American ANA‐positive healthy individuals were selected and demographically matched to ANA‐negative controls and SLE patients. Serum cytokine profiles, leukocyte subset frequency, and reactivity were analyzed by multiplex assays, immunophenotyping, and phosphospecific flow cytometry.ResultsOf 790 individuals screened, 57 (7%) were ANA‐positive. The majority of proinflammatory cytokines, including interferon‐γ (IFNγ), tumor necrosis factor, interleukin‐17 (IL‐17), and granulocyte colony‐stimulating factor, exhibited a stepwise increase in serum levels from ANA‐negative controls to ANA‐positive healthy individuals to SLE patients (P < 0.0001). IFNα, IFNβ, IL‐12p40, and stem cell factor/c‐Kit ligand were increased in SLE patients only (P < 0.05). B lymphocyte stimulator (BlyS) was elevated in SLE patients but decreased in ANA‐positive individuals (P < 0.001). Further, IL‐1 receptor antagonist (IL‐1Ra) was down‐regulated in SLE patients only (P < 0.0001). ANA‐positive individuals had increased frequencies of monocytes, memory B cells, and plasmablasts and increased levels of pSTAT‐1 and pSTAT‐3 following IFNα stimulation compared with ANA‐negative controls (P < 0.05).ConclusionANA‐positive healthy individuals exhibit dysregulation in multiple immune pathways yet differ from SLE patients by the absence of elevated IFNs, BLyS, IL‐12p40, and stem cell factor/c‐Kit ligand. Further, severely decreased levels of IL‐1Ra in SLE patients compared with ANA‐positive individuals may contribute to disease development. These results highlight the importance of IFN‐related pathways and regulatory elements in SLE pathogenesis.
Simultaneous determination of cucurbitacin IIa and cucurbitacin IIb of Hemsleya amabilis by HPLC–MS/MS and their pharmacokinetic study in normal and indomethacin‐induced rats
Authors: Wang Shougang , Guan Xiaohui , Zhong Xiuhong , Yang Zhiping , Huang Weili , Jia Baoyang , Cui Tao 
Published: April 2016

AbstractA selective and sensitive HPLC–MS/MS method was developed for the simultaneous determination of cucurbitacin IIa (cuIIa) and cucurbitacin IIb (cuIIb), the major bioactive cucurbitacins of Hemsleya amabilis, in rat plasma using euphadienol as internal standard (IS). After liquid–liquid extraction with dichloromethane, separation was achieved on a Syncronis HPLC C18 column (150 mm × 4.6 mm, 5 μm) using an isocratic mobile phase system consisting of acetonitrile–water (85:15, v/v) at a flow rate of 0.6 mL/min with a split ratio of 1:2. Detection was performed on a TSQ Quantum Ultra mass spectrometer equipped with an positive‐ion electrospray ionization source. The lower limits of quantification (LLOQs) were 0.25 and 0.15 ng/mL for cuIIa and cuIIb, respectively. The intra‐ and inter‐day precision was <11.5% for the LLOQs and each quality control level of the analytes, and accuracy was between −9.1 and 7.6%. The extraction recoveries of the analytes and IS from rat plasma were all >87.1%. The method was fully validated and applied to compare the pharmacokinetic profiles of the two cucurbitacins in rat plasma after oral administration of H. amabilis extract between normal and indomethacin‐induced rats. Copyright © 2016 John Wiley & Sons, Ltd.
Dermal fibroblasts induce cell cycle arrest and block epithelial–mesenchymal transition to inhibit the early stage melanoma development
Authors: Zhou Linli , Yang Kun , Randall Wickett R. , Zhang Yuhang 
Published: April 2016

AbstractStromal fibroblasts are an integral part of the tumor stroma and constantly interact with cancer cells to promote their initiation and progression. However, the role and function of dermal fibroblasts during the early stage of melanoma development remain poorly understood. We, therefore, designed a novel genetic approach to deactivate stromal fibroblasts at the onset of melanoma formation by targeted ablation of β‐catenin. To our surprise, melanoma tumors formed from β‐catenin‐deficient group (B16F10 mixed with β‐catenin‐deficient fibroblasts) appeared earlier than tumors formed from control group (B16F10 mixed with normal dermal fibroblasts). At the end point when tumors were collected, mutant tumors were bigger and heavier than control tumors. Further analysis showed that there were fewer amounts of stromal fibroblasts and myofibroblasts inside mutant tumor stroma. Melanoma tumors from control group showed reduced proliferation, down‐regulated expression of cyclin D1 and increased expression of cyclin‐dependent kinase inhibitor p16, suggesting dermal fibroblasts blocked the onset of melanoma tumor formation by inducing a cell cycle arrest in B16F10 melanoma cells. Furthermore, we discovered that dermal fibroblasts prevented epithelial‐mesenchymal transition in melanoma cells. Overall, our findings demonstrated that dermal fibroblasts crosstalk with melanoma cells to regulate in vivo tumor development via multiple mechanisms, and the outcomes of their reciprocal interactions depend on activation states of stromal fibroblasts and stages of melanoma development.