bluuebunny/crossref_metadata_2025 huggingface dataset:
Entdeckung und Strukturbestimmung eines ungewöhnlichen Sulfidtellurids mithilfe einer effektiven Kombination von TEM und Synchrotron‐Mikrodiffraktion
Authors: Fahrnbauer Felix , Rosenthal Tobias , Schmutzler Tilo , Wagner Gerald , Vaughan Gavin B. M. , Wright Jonathan P. , Oeckler Oliver
Published: July 2015

Anhand der Strukturanalyse des neuartigen Sulfidtellurids Pb8Sb8S15Te5 wird eine neue, vielseitig anwendbare Vorgehensweise vorgestellt, die den Synergismus von Elektronenmikroskopie und Beugungsexperimenten mit Synchrotronstrahlung für genaue Strukturanalysen von Nebenphasen in heterogenen mikrokristallinen Proben nutzt. Geeignete Kristallite unbekannter Phasen können mittels Transmissionselektronenmikroskopie identifiziert und mithilfe von Röntgenfluoreszenz‐Scans in einem mikrofokussierten Synchrotronstrahl wiedergefunden und zentriert werden. Das verfeinerte Strukturmodell wird anschließend durch Simulation von HRTEM‐Abbildungen desselben Kristallits bestätigt. Pb8Sb8S15Te5 besteht aus Ketten heterocubanartiger Einheiten. Die Kationenkoordinationspolyeder bilden ungewöhnlich verschlungene Ketten kanten‐ und flächenverknüpfter doppelt überkappter trigonaler Prismen. Die Strukturdaten sind ausreichend präzise für Bindungsvalenzrechnungen, die die fehlgeordnete Atomverteilung überzeugend bestätigen. Diese Methode ermöglicht die Optimierung der physikalischen Eigenschaften.
A Crystal Structure of a Functional RNA Molecule Containing an Artificial Nucleobase Pair
Authors: Hernandez Armando R. , Shao Yaming , Hoshika Shuichi , Yang Zunyi , Shelke Sandip A. , Herrou Julien , Kim Hyo‐Joong , Kim Myong‐Jung , Piccirilli Joseph A. , Benner Steven A.
Published: July 2015

As one of its goals, synthetic biology seeks to increase the number of building blocks in nucleic acids. While efforts towards this goal are well advanced for DNA, they have hardly begun for RNA. Herein, we present a crystal structure for an RNA riboswitch where a stem C:G pair has been replaced by a pair between two components of an artificially expanded genetic‐information system (AEGIS), Z and P, (6‐amino‐5‐nitro‐2(1H)‐pyridone and 2‐amino‐imidazo[1,2‐a]‐1,3,5‐triazin‐4‐(8H)‐one). The structure shows that the Z:P pair does not greatly change the conformation of the RNA molecule nor the details of its interaction with a hypoxanthine ligand. This was confirmed in solution by in‐line probing, which also measured a 3.7 nM affinity of the riboswitch for guanine. These data show that the Z:P pair mimics the natural Watson–Crick geometry in RNA in the first example of a crystal structure of an RNA molecule that contains an orthogonal added nucleobase pair.
Synthetische Oligosaccharide belegen die immunologische Bedeutung der Pyruvatmodifikation im Kapselpolysaccharid von Serotyp 4 Streptococcus pneumoniae
Authors: Pereira Claney L. , Geissner Andreas , Anish Chakkumkal , Seeberger Peter H.
Published: July 2015

Nach allgemeiner Annahme wird die Immunogenität von Kohlenhydraten stark von deren Modifikationen beeinflusst. Kapselpolysaccharide (KPS) von pathogenen Bakterien enthalten häufig ein Pyruvat, das als Acetal die 4,6‐, 3,4‐ oder 2,3‐Positionen überbrücken kann. Das KPS von Serotyp 4 Streptococcus pneumoniae (ST4) ist mit einem trans‐2,3‐verknüpften Pyruvat modifiziert. Um die immunologische Bedeutung dieser Modifikation zu untersuchen, wurde die Wiederholungseinheit dieses Polysaccharids erstmals chemisch synthetisiert. Bei der Analyse von Antikörpern gegen ST4‐KPS mithilfe eines Kohlenhydratmikroarrays, der verschiedene Substrukturen des KPS enthält, konnte eine exklusive Bindung an die Wiederholungseinheit mit Pyruvat festgestellt werden. Das Pyruvatacetal ist somit ein Schlüsselmotiv für die Entwicklung minimaler synthetischer Kohlenhydratimpfstoffe gegen ST4.
Pinensins: The First Antifungal Lantibiotics
Authors: Mohr Kathrin I. , Volz Carsten , Jansen Rolf , Wray Victor , Hoffmann Judith , Bernecker Steffen , Wink Joachim , Gerth Klaus , Stadler Marc , Müller Rolf
Published: July 2015

Lantibiotics (lanthionine‐containing antibiotics) from Gram‐positive bacteria typically exhibit activity against Gram‐positive bacteria. The activity and structure of pinensin A (1) and B (2), lantibiotics isolated from a native Gram‐negative producer Chitinophaga pinensis are described. Surprisingly, the pinensins were found to be highly active against many filamentous fungi and yeasts but show only weak antibacterial activity. To the best of our knowledge, lantibiotic fungicides have not been described before. An in‐depth bioinformatic analysis of the biosynthetic gene cluster established the ribosomal origin of these compounds and identified candidate genes encoding all of the enzymes required for post‐translational modification. Additional encoded functions enabled us to build up a hypothesis for the biosynthesis, export, sensing, and import of this intriguing lantibiotic.
Gold(I)‐Catalyzed Tandem Transformation with Diynes: Rapid Access to Linear Cyclopentenone‐Fused Polycyclic Molecules
Authors: Yu Congjun , Chen Bin , Zhou Tian , Tian Qingshan , Zhang Guozhu
Published: July 2015

An efficient and convenient synthesis of useful linear cyclopentenone‐fused polycyclic compounds has been achieved through a novel gold(I)‐catalyzed transformation of diynes. The method demonstrates high product yields and tolerates of a wide variety of important functional groups. Gold‐vinylidene formation, methoxy group migration, and Nazarov‐type cyclization are proposed to be the key steps in the reaction pathway. The synthetic utility of this method is demonstrated by converting the product to eight‐membered‐ring‐fused compound.
Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes
Authors: Orthaber Andreas , Löfås Henrik , Öberg Elisabet , Grigoriev Anton , Wallner Andreas , Jafri S. Hassan M. , Santoni Marie‐Pierre , Ahuja Rajeev , Leifer Klaus , Ottosson Henrik , Ott Sascha
Published: July 2015

Acetylenic phosphaalkenes (APAs) are used as a novel type of ligands for the stabilization of gold nanoparticles (AuNP). As demonstrated by a variety of experimental and analytical methods, both structural features of the APA, that is, the PC as well as the CC units are essential for NP stabilization. The presence of intact APAs on the AuNP is demonstrated by surface‐enhanced Raman spectroscopy (SERS), and first principle calculations indicate that bonding occurs most likely at defect sites on the Au surface. AuNP‐bound APAs are in chemical equilibrium with free APAs in solution, leading to a dynamic behavior that can be explored for facile place‐exchange reactions with other types of anchor groups such as thiols or more weakly binding phosphine ligands.
Chemical Synthesis Elucidates the Immunological Importance of a Pyruvate Modification in the Capsular Polysaccharide of Streptococcus pneumoniae Serotype 4
Authors: Pereira Claney L. , Geissner Andreas , Anish Chakkumkal , Seeberger Peter H.
Published: July 2015

Carbohydrate modifications are believed to strongly affect the immunogenicity of glycans. Capsular polysaccharides (CPS) from bacterial pathogens are frequently equipped with a pyruvate that can be placed across the 4,6‐, 3,4‐, or 2,3‐positions. A trans‐2,3‐linked pyruvate is present on the CPS of the Gram‐positive bacterium Streptococcus pneumoniae serotype 4 (ST4), a pathogen responsible for pneumococcal infections. To assess the immunological importance of this modification within the CPS repeating unit, the first total synthesis of the glycan was carried out. Glycan microarrays containing a series of synthetic antigens demonstrated how antibodies raised against natural ST4 CPS specifically recognize the pyruvate within the context of the tetrasaccharide repeating unit. The pyruvate modification is a key motif for designing minimal synthetic carbohydrate vaccines for ST4.
Structure Elucidation and Characterization of Different Thyroxine Polymorphs
Authors: Mondal Santanu , Mugesh Govindasamy
Published: July 2015

Thyroid hormones regulate almost every process in the body, including body temperature, growth, and heart rate. They influence carbohydrate metabolism, protein synthesis and breakdown, and cardiovascular, renal, and brain function. Two new polymorphs of synthetic L‐thyroxine (T4) are reported and the effect of polymorphism on the solubility of this important hormone is shown. Conformational changes were also discovered to have a remarkable effect on the strength of halogen bonding and the reactivity of the CI bonds, which could have a significant effect on the hormone activity.
Modification of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) properties by reactive blending with a monoterpene derivative
Authors: Pilon Laura , Kelly Catherine
Published: July 2015

A one‐step reactive blending approach is reported for modification of the thermal and mechanical properties of poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate). A free‐radical initiated reaction of the monoterpene derivative, linalool, was carried out with PHBV in the melt. This processing led to a reduction in the material melt temperature and increase in the tensile strength and elongation at break. Reduced embrittlement over time was also evident in the reactive blended materials in an ambient temperature ageing study, suggestive of reduced secondary crystallization. The nature of the structural changes within the materials could not be fully elucidated, but evidence pointed to free radical cross‐linking, mediated by the linalool, as a major component of the changes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42588.
Synthesis of chitosan derivative with dual‐antibacterial functional groups and its antibacterial activity
Authors: Li Zhihan , Yang Fei , Yang Rendang
Published: July 2015

The O‐fumaryl ester (OFTMCS) of N,N,N‐trimethyl chitosan (TMCS) has been synthesized as a water‐soluble chitosan (CS) derivative bearing dual‐functional groups, with the aim of discovering novel CS derivatives with good water solubility and enhanced the antibacterial activity compared with unmodified CS. OFTMCS was characterized by FT‐IR, 13C NMR, XPS, XRD and Zeta potential analyses. The XPS results indicated that the degree of substitution (DS) on the C2‐NH2 group of the CS was 0.78, and that the DS on its C6‐OH group was 0.31. The TGA results showed that the thermal stability of OFTMCS was lower than that of unmodified CS. The antibacterial activities of OFTMCS were investigated by assessing the mortality rates of the representative Gram‐positive and Gram‐negative bacteria Staphylococcus aureus and Escherichia coli, respectively. The results indicated that OFTMCS exhibited superior antibacterial activity to CS at a lower dosage. The synthesis of CS derivatives bearing dual‐functional groups could therefore be used as a promising strategy to enhance the antibacterial activity of CS. The antimicrobial mechanism of action of OFTMCS was discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42663.
Improving electrical conductivity of poly methyl methacrylate by utilization of carbon nanotube and CO2 laser
Authors: Ghavidel Ayub Karimzad , Azdast Taher , Shabgard Mohammadreza , Navidfar Amir , Sadighikia Sina
Published: July 2015

In this work, the electrical surface conductivity enhancement of injection‐molded multiwalled carbon nanotube (MWCNT)/poly(methyl methacrylate) (PMMA) nanocomposite by using CO2 laser processing was studied. Variable input factors are considered as MWCNT concentration (in three levels 0.5, 1, and 1.5 wt %), the laser feed angle with the flow direction (in five levels 0°, 30°, 45°, 75°, and 90°), and the cavity machining method that were produced by electrodischarge machining and computer numerical control milling with finishing process. The studies show that the irradiation of laser and utilization of covering gas could enhance the CNT–CNT contacts and the surface electrical conductivity. The morphology of laser‐irradiated surface by using scanning electron microscope certified that the conductive network generated from CNT–CNT contacts can transfer the electrical current. The findings clearly show that the laser feed angle with the flow direction influenced the electrical conductivity. The maximum conductivity (∼ 5.310 × 10−4 S) was observed at 75°. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42671.
In‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to miniemulsion polymerization
Authors: Tamai Toshiyuki , Watanabe Mitsuru , Matsukawa Kimihiro
Published: July 2015

We present in‐situ formation of metal nanoparticle/acrylic polymer hybrid and its application to prepare hybrid latex particles by miniemulsion polymerization. On the surface of a silver nanoparticle/silica nanoparticle/acrylic polymer hybrid layer formed in‐situ on a polyethylene terephthalate (PET) substrate, a copper film is deposited using electroless copper deposition. Silver nanoparticles, which are formed in‐situ via the reduction of silver ion by radical species and subsequent annealing, work as a catalyst for the electroless deposition. Miniemulsion polymerization via the in‐situ formation of nanoparticles affords nanoparticle/acrylic polymer hybrid latex particles and polymer particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42675.
Length scale dependent deformation in natural rubber
Authors: Chandrashekar Gurudutt , Alisafaei Farid , Han Chung‐Souk
Published: July 2015

Strong length scale dependent deformation has been previously observed in the elastomer polydimethylsiloxane by indentation type experiments at micro‐ to nanometer length scales with a sharp conical tip. To examine if other nonsilicone based elastomers exhibit similar length scale dependent deformation behavior, natural rubber has been chosen in this study. Performing indentation type tests with a nanoindentation system, the universal hardness and the elastic modulus are determined at different probing depths ranging from about 90 to 5 μm to characterize length scale dependent deformation behavior in natural rubber. The testing with a Berkovich tip resulted in an amazing increase in the universal hardness with decreasing probing depth indicating that the deformation mechanisms at the micrometer length scales are significantly different as compared to those at the macroscopic length scales. The observed length scale dependent deformation is associated with an increase in rotation gradients with decreasing probing depth. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42683.
Polyisoprene modified poly(alkyl acrylate) foam as oil sorbent material
Authors: Ratcha Arissara , Samart Chanatip , Yoosuk Boonyawan , Sawada Hideo , Reubroycharoen Prasert , Kongparakul Suwadee
Published: July 2015

Biorenewable polyisoprene latex obtained from natural rubber, Hevea brasiliensis, was used to prepare the reusable polyisoprene–poly(alkyl acrylate) foam for petroleum‐based liquid absorption. The foam was produced via latex vulcanization and cured by steaming. The effect of various types of poly(alkyl acrylate) such as poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), and poly(butyl acrylate) (PBA) on oil sorption capacity of the foam were studied. Scanning electron microscope (SEM) images showed interconnected open‐cell macrostructure with the foam porosity greater than 75% and good compression set. The oil sorption capacity of the foam was in the range of 2.0–16.6 g g−1. The addition of poly(alkyl acrylate) enhanced hydrophobicity and oil sorption capacity of the foam. The absorbed oil was easily recovered by squeezing and the foam can be reused up to 30 sorption–desorption cycles and still preserve high quality sorption. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42688.
Fluorinated networks dynamics studied by means of broadband dielectric spectroscopy
Authors: Miccio Luis A. , Otegui Jon , Penoff Marcela E. , Montemartini Pablo E. , Schwartz Gustavo A.
Published: July 2015

The influence of the surface chemical modification on the bulk behavior of epoxy based networks has been studied. In particular, the bulk dynamics of epoxy‐amine networks modified with fluorinated side chains has been characterized by means of broadband dielectric spectroscopy (BDS), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The fluorination effect on the structure and dynamics of the materials has been related with the observed changes in both segmental and secondary relaxations. An acceleration of the segmental dynamics as the fluorination degree increases has been clearly observed. As a result, a compromise between fluorine surface enrichment and bulk modification has been proposed for these materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42690.
Preparation and properties of porous polytetrafluoroethylene hollow fiber membrane through mechanical operations
Authors: Liu Guochang , Gao Congjie , Li Xiaoming , Guo Chungang , Chen Ying , Lv Jinglie
Published: July 2015

Porous polytetrafluoroethylene (PTFE) hollow fiber membranes were prepared from fine powder through a series of mechanical operations including paste extrusion, heat treatment, stretching and sintering. In contrast to conventional process, the heat treatment used in this study was performed at 200°C to 330°C (near the melting point) on the PTFE nascent hollow fiber (precursor of membrane). The results showed that the introduction of heat treatment step effectively improved the mechanical properties of precursors, the ultimate stress and strain increased observably with heat treatment temperature, which was beneficial to subsequently stretching precursors to make them porous. Furthermore, the morphological changes and improvement of membrane properties caused by stretching operation were investigated for porous PTFE hollow fiber membrane having finer pore size and higher porosity. The porous microstructure of nodes interconnected by fibrils varied depending on the stretching conditions, such as the stretching temperature, rate, and ratio. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42696.
Mixture design applied for the development of films based on starch, polyvinyl alcohol, and glycerol
Authors: Zanela Juliano , Olivato Juliana Bonametti , Dias Adriana Passos , Grossmann Maria Victória Eiras , Yamashita Fabio
Published: July 2015

Starch and polyvinyl alcohol (PVA) are biodegradable materials with potentiality to replace the conventional polymers in some applications. The aim of this work was to produce biodegradable films of PVA, cassava starch, and glycerol by thermoplastic extrusion using a mixture design to evaluate the effects of each component in the blend properties. Six formulations were prepared using a twin‐screw extruder coupled with a calender. All the materials were visually homogeneous and presented good processability. Mechanical properties were dependent on both the relative humidity conditioning and the formulation; higher relative humidities detracted the mechanical properties, which was associated to plasticizer effect of the water. Furthermore, the mechanical properties were better when higher concentrations of PVA were used, resulting in films with lower opacity, lower water vapor permeability, and higher thermal stability, according to TGA. Biodegradable materials based on starch, PVA, and glycerol have adequate mechanical and processing properties for commercial production. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42697.
Probing small network differences in sulfur‐cured rubber compounds by combining nuclear magnetic resonance and swelling methods
Authors: Dibbanti Murali Krishna , Mauri Michele , Mauri Lucio , Medaglia Gabriele , Simonutti Roberto
Published: July 2015

We studied the network structure of elastomers based on polyisoprene, polybutadiene, and their blends in the narrow range of formulations compatible with actual use in the automotive tyre industry. Cross‐link density (CLD) was quantified comparatively by low‐field 1H multiple quantum time domain nuclear magnetic resonance (MQ TD‐NMR) and by equilibrium swelling technique. The robustness and agreement of the two methods was demonstrated in measuring minute alterations of unfilled vulcanizates beyond the optimum cure time. Comparison with samples where polysulfidic bonds were selectively cleaved also demonstrates that the length of the sulfur chain constituting the cross‐link does not significantly affect residual dipolar coupling. Kraus, Lorenz, and Parks correction for filler restriction on swelling is validated by MQ TD‐NMR, which also allows extracting information on cross‐link distribution not provided by swelling measurement. Cross‐link distributions in the blends were demonstrated to be significantly different from the weighted average of the pure samples, while average proton–proton residual dipolar coupling values correspond. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42700.
Effects of maleic anhydride grafted polyethylene on rheological, thermal, and mechanical properties of ultra high molecular weight polyethylene/poly(ethylene glycol) blends
Authors: He Shuai , He Hui , Li Yingchun , Wang Dongqing
Published: July 2015

Ultra‐high molecular weight polyethylene (UHMWPE) has gained considerable fame due to its excellent wear and mechanical properties, though the inferior processability has restricted its further extensive applications. In this study, a combination of UHMWPE and poly(ethylene glycol) (PEG) was considered based on the recent reports, and aiming to further exploit the potential of PEG that acts as processing aid, and also to obtain greater enhanced processability along with other properties, the effects of incorporating maleic anhydride grafted polyethylene (MAPE) was thoroughly investigated. Rheological tests revealed a further significant reduction in melt viscosity of UHMWPE/PEG blends after MAPE introduced, showing a potential of better processability, while the flexural strength and toughness of UHMWPE blends experienced a satisfying increase without any obvious compromises in other mechanical properties. A slight improvement of thermal stability in UHMWPE ternary blends along with an increase of vicat softening temperature were characterized by thermal tests, while the crystallinity of UHMWPE was diminished after the introduction of MAPE. Morphology analysis indicated that better dispersion and decreased size of PEG particles were achieved in UHMWPE matrix when MAPE was incorporated, which confirmed the improved interfacial interactions and other reinforcements obtained in UHMWPE/PEG/MAPE blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42701.
Fabrication of hierarchically crystallographic morphologies in isotactic polypropylene
Authors: Wang Ming , Yuan Jia , Luo Shi‐Hui , Zeng Jian‐Bing
Published: July 2015

The hierarchically crystallographic morphologies were fabricated in isotactic polypropylene (iPP) by controlling the stratified distribution of the nucleating agents. The α‐ and β‐nucleating agents were chosen for preparing the different crystalline modifications. The transcrystals and spherulites were found in the stratified distribution samples by polar optical microscopy (POM) and scanning electron microscope (SEM). The transcrystals grew from the surfaces of the nucleating agents filled layers and occupied most space of the pure iPP layers. The crystalline modifications and crystallinity were analyzed by X‐ray diffraction (XRD) and differential scanning calorimeter (DSC) analysis. The mechanical and thermal degradation properties of these samples with hierarchically crystallographic morphologies were investigated by tensile testing machine and thermogravimetric analysis (TGA) respectively, and showed better than that of the samples with single crystallographic morphology (spherulites). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42703.
Modification of poly(ethylene terephthalate) by combination of reactive extrusion and followed solid‐state polycondensation for melt foaming
Authors: Yan Haichao , Yuan Haitao , Gao Feng , Zhao Ling , Liu Tao
Published: July 2015

A combination of reactive extrusion and followed solid‐state polycondensation (SSP) was applied to modify the virgin fiber grade poly(ethylene terephthalate) (v‐PET) and recycled bottle‐grade PET (r‐PET) for melt foaming. Pyromellitic dianhydride (PMDA) and triglycidyl isocyanurate (TGIC) were chosen as the modifiers for the reactive extrusion performed in a twin‐screw extruder. For comparison, commercially available chain extender ADR JONCRYL ADR‐4370‐S was also used. The characterizations of the intrinsic viscosity, i.e., [η], and rheological properties whose changes were correlated to the long chain branches introduced in the molecular structure were performed on the modified PET to evaluate their chain extension extent. The results revealed that the [η] of 1.37 dL/g was obtained for PMDA modified v‐PET while that of 1.15 dL/g for TGIC modified r‐PET. Such difference was attributed to the different reactivity of the two chain extenders with the two types of PET. Increases in shear viscosity and storage modulus, and the high pronounced shear thinning behavior were also observed in the modified PET. Finally, the foamability of the certain modified PET was verified by the batch melt foaming experiments. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42708.
Preparation of dual‐layer acetylated methyl cellulose hollow fiber membranes via co‐extrusion using thermally induced phase separation and non‐solvent induced phase separation methods
Authors: Jang Hanna , Song Du‐Hyun , Lee Hye‐Jin , Lim Seong‐Han , Kim In‐Chul , Kwon Young‐Nam
Published: July 2015

Dual‐layer acetylated methyl cellulose (AMC) hollow fiber membranes were prepared by coupling the thermally induced phase separation (TIPS) and non‐solvent induced phase separation (NIPS) methods through a co‐extrusion process. The TIPS layer was optimized by investigating the effects of coagulant composition on morphology and tensile strength. The solvent in the aqueous coagulation bath caused both delayed liquid–liquid demixing and decreased polymer concentration at the membrane surface, leading to porous structure. The addition of an additive (triethylene glycol, (TEG)) to the NIPS solution resolved the adhesion instability problem of the TIPS and NIPS layers, which occurred due to the different phase separation rates. The dual‐layer AMC membrane showed good mechanical strength and performance. Comparison of the fouling resistance of the AMC membranes with dual‐layer polyvinylidene fluoride (PVDF) hollow fiber membranes fabricated with the same method revealed less fouling of the AMC than the PVDF hollow fiber membrane. This study demonstrated that a dual‐layer AMC membrane with good mechanical strength, performance, and fouling resistance can be successfully fabricated by a one‐step process of TIPS and NIPS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42715.
Correlation of the Osteoarthritis Susceptibility Variants That Map to Chromosome 20q13 With an Expression Quantitative Trait Locus Operating on NCOA3 and With Functional Variation at the Polymorphism rs116855380
Authors: Gee Fiona , Rushton Michael D. , Loughlin John , Reynard Louise N.
Published: July 2015

Objective

To functionally characterize the osteoarthritis (OA) susceptibility variants that map to a region of high linkage disequilibrium (LD) on chromosome 20q13 marked by the single‐nucleotide polymorphism (SNP) rs6094710 and encompassing NCOA3 and SULF2.

Methods

Nucleic acids were extracted from the cartilage of OA patients. Overall and allelic expression of NCOA3 and SULF2 were measured by quantitative reverse transcription–polymerase chain reaction and pyrosequencing, respectively. The functional effect of SNPs within the 20q13 locus was assessed in vitro using luciferase reporter constructs and electrophoretic mobility shift assays (EMSAs). The in vivo effect of nuclear receptor coactivator 3 (NCOA3) protein depletion on primary human OA articular cartilage chondrocytes was assessed using RNA interference.

Results

Expression of NCOA3 correlated with the genotype at rs6094710 (P = 0.006), and the gene demonstrated allelic expression imbalance (AEI) in individuals heterozygous for the SNP (mean AEI 1.21; P < 0.0001). In both instances, expression of the OA‐associated allele was reduced. In addition, there was reduced enhancer activity of the OA‐associated allele of rs116855380, a SNP in perfect LD with rs6094710 in luciferase assays (P < 0.001). EMSAs demonstrated a protein complex binding with reduced affinity to this allele. Depletion of NCOA3 led to significant changes (all P < 0.05) in the expression of genes involved in cartilage homeostasis.

Conclusion

NCOA3 is subject to a cis‐acting expression quantitative trait locus in articular cartilage, which correlates with the OA association signal and with the OA‐associated allele of the functional SNP rs116855380, a SNP that is located only 10.3 kb upstream of NCOA3. These findings elucidate the effect of the association of the 20q13 region on OA cartilage and provide compelling evidence of a potentially causal candidate SNP.
Dynamic Covalent Chemistry of Nucleophilic Substitution Component Exchange of Quaternary Ammonium Salts
Authors: Kulchat Sirinan , Lehn Jean‐Marie
Published: July 2015

Dynamic covalent libraries (DCLs) of quaternary ammonium cations were set up by reversible nucleophilic substitution (SN2′ and SN2) exchange reactions of ammonium salts and tertiary amines. The reactions were conducted at 60 °C to generate thermodynamically and kinetically controlled mixtures of quaternary ammonium compounds and tertiary amines, and were accelerated by using iodide as a nucleophilic catalyst. Microwave irradiation was used to assist the exchange reaction between the pyridinium salts and pyridine derivatives. Finally, experiments towards the generation of dynamic ionic liquids were performed. The results of this study pave the way for the extension of dynamic combinatorial chemistry to nucleophilic substitution reactions.
Graphene / Single‐Walled Carbon Nanotube Composites Generated by Covalent Cross‐Linking
Authors: Pramoda K. , Kumar Ram , Rao C. N. R.
Published: July 2015

Composites of graphene and single‐walled carbon nanotubes (SWNT) have been generated by covalent cross‐linking through two different coupling strategies, namely Sonogashira and EDC (1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide) coupling reactions. The obtained assemblies have been characterized by various microscopic and spectroscopic techniques. The assemblies obtained by Sonogashira coupling exhibit high surface area, the value increasing with the graphene content. The highest surface area obtained is 1260 m2 g−1 in the composition with highest graphene content (graphene:SWNT 1:4). These composites show a uniform slit‐shaped porous network with pores of approximately 1–2 nm. CO2 uptake of this assemblies is in the range 11–15 wt % at 273 K (1 atm) and 9–11 wt % at 298 K (1 atm), whereas the H2 uptake is in the 1–1.3 wt % range at 77 K (1 atm). The composites generated by Sonogashira coupling show superhydrophobicity with high contact angles in the range from 159–163°. The EDC‐coupled composites show less surface area than the composites from Sonogashira coupling.
Photoinduced Electron Transfer of Porphyrin Isomers: Impact of Molecular Structures on Electron‐Transfer Dynamics
Authors: Fujitsuka Mamoru , Majima Tetsuro
Published: July 2015

Porphyrins have been investigated for a long time in various fields of chemistry owing to their excellent redox and optical properties. Structural isomers of porphyrins have been synthesized, namely, porphycene, hemiporphycene, and corrphycene. Although the number of studies on these structural isomers is limited, they exhibit interesting properties suitable for various applications such as photovoltaic devices, photocatalysts, and photodynamic therapy. In the present review, we summarized their photoinduced electron‐transfer processes, which are key steps of various photofunctions. Their electrochemical and photophysical properties are summarized as basic properties for the electron transfer. Furthermore, differences among these isomers in the electron‐transfer processes are clarified, and its origin has been discussed on the basis of their molecular structures.
6,7‐Bismethoxy‐2,11‐dihydroxytetraphenylene Derived Macrocycles: Synthesis, Structures, and Complexation with Fullerenes
Authors: Deng Chun‐Lin , Xiong Xiao‐Dong , Chik David T. W. , Cai Zongwei , Peng Xiao‐Shui , Wong Henry N. C.
Published: July 2015

6,7‐Bismethoxy‐2,11‐dihydroxytetraphenylene (1), a novel building block of tetraphenylene‐derived macrocycles, was synthesized via palladium‐catalyzed cross‐coupling reactions and characterized by X‐ray diffraction. The relevant macrocyclic hosts derived from 1 have well‐defined structures with fixed conformations both in solution and solid state. They showed efficient and unique properties toward complexation with fullerenes C60 and C70 in toluene.
A Hybrid Supramolecular Polymeric Hydrogel with Rapid Self‐Healing Property
Authors: Chen Lin , Chen Hui , Yao Xuyang , Ma Xiang , Tian He
Published: July 2015

A hybrid supramolecular polymeric hydrogel is conveniently constructed via host–guest interaction of a host cyclodextrin polymer (poly‐CD) with a guest α‐bromonaphthalene polymer (poly‐BrNp) and mixing with 6‐thio‐β‐cyclodextrin (β‐SH‐CD) modified gold nanoparticles (GPCDs) in aqueous solution. According to the dynamic oscillatory data, the hydrogel exhibits markedly enhanced stiffness compared with the GPCD‐free one (both G′ and G“ values are almost twice as high as those of the original GPCD‐free hydrogel) due to the introduction of the inorganic gold nanoparticles. This hybrid supramolecular polymeric hydrogel has a rapid and excellent self‐healing property (only about 1 min, and the G′ and G” of the self‐healed hydrogel almost turned back to their original levels after 1 hour) in air (without adding any solvent or additive).
Partitioning in aqueous two‐phase systems: Analysis of strengths, weaknesses, opportunities and threats
Authors: Soares Ruben R. G. , Azevedo Ana M. , Van Alstine James M. , Aires‐Barros M. Raquel
Published: July 2015

For half a century aqueous two‐phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single‐use, flexible biomanufacturing has led to industrial re‐evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi‐stage operations and in single‐step purification processes.
Prediction of reversible IgG1 aggregation occurring in a size exclusion chromatography column is enabled through a model based approach
Authors: Ojala Frida , Sellberg Anton , Hansen Thomas Budde , Hansen Ernst Broberg , Nilsson Bernt
Published: July 2015

One important aspect of antibody separation being studied today is aggregation, as this not only leads to a loss in yield, but aggregates can also be hazardous if injected into the body. The aim of this study was to determine whether the methodology applied in the previous study could be used to predict the aggregation of a different batch of IgG1, and to model the aggregation occurring in a SEC column. Aggregation was found to be reversible. The equilibrium parameter was found to be 272 M‐1 and the reaction kinetic parameter 1.33 × 10‐5 s‐1, both within the 95% confidence interval of the results obtained in the previous work. The effective diffusivities were estimated to be 1.45 × 10‐13 and 1.90 10‐14 m2/s for the monomers and dimers, respectively. Good agreement was found between the new model and the chromatograms obtained in the SEC experiments. The model was also able to predict the decrease of dimers due to the dilution and separation in the SEC column during long retention times.
AVP‐IC50Pred: Multiple machine learning techniques‐based prediction of peptide antiviral activity in terms of half maximal inhibitory concentration (IC50)
Authors: Qureshi Abid , Tandon Himani , Kumar Manoj
Published: July 2015

Peptide‐based antiviral therapeutics has gradually paved their way into mainstream drug discovery research. Experimental determination of peptides' antiviral activity as expressed by their IC50 values involves a lot of effort. Therefore, we have developed “AVP‐IC50Pred,” a regression‐based algorithm to predict the antiviral activity in terms of IC50 values (μM). A total of 759 non‐redundant peptides from AVPdb and HIPdb were divided into a training/test set having 683 peptides (T683) and a validation set with 76 independent peptides (V76) for evaluation. We utilized important peptide sequence features like amino‐acid compositions, binary profile of N8‐C8 residues, physicochemical properties and their hybrids. Four different machine learning techniques (MLTs) namely Support vector machine, Random Forest, Instance‐based classifier, and K‐Star were employed. During 10‐fold cross validation, we achieved maximum Pearson correlation coefficients (PCCs) of 0.66, 0.64, 0.56, 0.55, respectively, for the above MLTs using the best combination of feature sets. All the predictive models also performed well on the independent validation dataset and achieved maximum PCCs of 0.74, 0.68, 0.59, 0.57, respectively, on the best combination of feature sets. The AVP‐IC50Pred web server is anticipated to assist the researchers working on antiviral therapeutics by enabling them to computationally screen many compounds and focus experimental validation on the most promising set of peptides, thus reducing cost and time efforts. The server is available at http://crdd.osdd.net/servers/ic50avp. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 753–763, 2015.
5‐aminomethyloxazolidine‐2,4‐dione hybrid α/β‐dipeptide scaffolds as inductors of constrained conformations: Applications to the synthesis of integrin antagonists
Authors: De Marco Rossella , Mazzotti Giacomo , Dattoli Samantha D. , Baiula Monica , Spampinato Santi , Greco Arianna , Gentilucci Luca
Published: July 2015

Peptidomimetics represent an attractive starting point for drug discovery programs; in particular, peptidomimetics that result from the incorporation of a heterocycle may take advantage of increased enzymatic stability and higher ability to reproduce the bioactive conformations of the parent peptides, resulting in enhanced therapeutic potential. Herein, we present mimetics of the α4β1 integrin antagonist BIO1211 (MPUPA‐Leu‐Asp‐Val‐Pro‐OH), containing a aminomethyloxazolidine‐2,4‐dione scaffold (Amo). Interestingly, the retro‐sequences PhCOAsp(OH)‐Amo‐APUMP including either (S)‐ or (R)‐configured Amo displayed significant ability to inhibit the adhesion of α4β1 integrin expressing cells, and remarkable stability in mouse serum. Possibly, the conformational bias exerted by the Amo scaffold determined the affinity for the receptors. These peptidomimetics could be of interest for the development of small‐molecule agents effective against inflammatory processes and correlated autoimmune diseases. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 636–649, 2015.
Repositioning Irsogladine to Hsp90 Inhibitor
Authors: Seo Young Ho
Published: July 2015

|Heat shock protein 90 (Hsp90) is a ubiquitous adenosine triphosphate (ATP)‐dependent molecular chaperone and represents an attractive cancer therapeutic target due to its role in maintaining the correct folding and stability of many oncogenic proteins. In our effort to repurpose existing drugs to Hsp90 inhibitors, we screened Food and Drug Administration (FDA) approved drugs based on chemical structure similarity and discovered that a mucosal protective drug, irsogladine, inhibits the Hsp90 folding machinery. In vitro fluorescence polarization assay and cell‐based mechanism study demonstrate that irsogladine binds to the ATP‐binding pocket in N‐terminal domain of Hsp90 and impairs the Hsp90 chaperoning function. Consequently, irsogladine induces the downregulation of Hsp90 client proteins including Her2, Akt, and Cdk4 and upregulation of the co‐chapereone Hsp70.
Simultaneous Detection of F− and CN− by a Simple Colorimetric Chemosensor with High Selectivity
Authors: Lee Jung Hyun , Lee Sang Ho , So Yun A , Park Gyeong Jin , Kim Cheal
Published: July 2015

A julolidine–nitroaniline conjugate as a new simple colorimetric chemosensor 1 for the detection of both F− and CN
− has been developed. This sensor could simultaneously detect two biologically important anions (F− and CN
−) through colorimetric methods over most other competitive anions. It exhibited a distinct color change from yellow to orange upon addition of F− through deprotonation process. In addition, the sensor 1 displayed an obvious color change from yellow to colorless upon binding with CN
− through a nucleophilic addition mechanism. Thus, this sensor exhibits a new method to simultaneously assay F− and CN
− with different color change in the same solvent environment.
Synthesis of Anatase Mesoporous TiO2 by Using Cyclodextrin as a Pore Forming Template via Hydrothermal Treatment
Authors: Kim Joohee , An Soyoung , Jang Soehyun , Lee Junwoo , Chung Jae Woo
Published: July 2015

Porous titanium dioxide with an average pore diameter of several nanometers and a narrow pore size distribution was prepared by using cyclodextrin (CD) in a sol–gel reaction of titanium precursor. After the reaction, a hydrothermal treatment was performed, and a WAXD analysis shows that the hydrothermal treatment successfully induces an anatase crystalline structure in TiO2
. The combined results from TGA, FT‐IR, N2
adsorption–desorption isotherm, TEM, and SEM analyses show that the CD act as a pore forming template to form TiO2
with a wormhole‐type pore and a large specific surface area. Furthermore, the ratio of the CD/Ti precursor affects the porosity and the morphology of the mesoporous TiO2
. In contrast, TiO2
prepared without CD does not exhibit a porous structure. The formation of these porous structures is a result of the self‐assembly of Ti species around the CD molecules, TiO2
growth, and pore‐forming by the removal of CD.
The Importance of Perceived Organisational Goals: A Systems Thinking Approach to Understanding Child Safeguarding in the Context of Domestic Abuse
Authors: Caffrey Louise
Published: July 2015

Research in the late 1990s and early 2000s raised concerns that the safeguarding implications of domestic abuse (DA) were not being sufficiently accounted for in child contact cases in England. Since that time, reforms have been introduced, which sought to emphasise the importance of safety in this context. Despite these developments, there is concern that problematic management of DA cases may have persisted. This article presents findings on the management of DA in supported child contact centres in England. The findings suggest that supported contact services continue to facilitate DA cases, although the service is not designed for this purpose. Using the systems thinking concepts of ‘local rationalities’ and ‘goal conflicts’, the article explores how problematic safeguarding practices made sense to those on the ground. The findings suggest that supported services are inappropriate for cases involving DA concerns, not just because they lack the resources to safely manage these cases, but because their perceived organisational goals can present a conflict for staff and volunteers in safely managing them. Ultimately, the article asserts the potential for perceived organisational goals to impact on practice and thus the importance of considering them in the design, commissioning or use of services. Copyright © 2015 John Wiley & Sons, Ltd.

‘Presents findings on the management of DA in supported child contact centres in England’

Key Practitioner Messages

Supported child contact centres are inappropriate for cases involving DA concerns but continue to be used to facilitate such cases.

Perceived organisational goals can impact on practice. It is therefore important to consider them in the design, commissioning or use of services.

Systems thinking concepts, including ‘local rationalities’ and ‘goal conflicts’, can provide a useful framework for investigating the root causes of problematic practice.

‘Perceived organisational goals can impact on practice’
Homoserine Lactones, Methyl Oligohydroxybutyrates, and Other Extracellular Metabolites of Macroalgae‐Associated Bacteria of the Roseobacter Clade: Identification and Functions
Authors: Ziesche Lisa , Bruns Hilke , Dogs Marco , Wolter Laura , Mann Florian , Wagner‐Döbler Irene , Brinkhoff Thorsten , Schulz Stefan
Published: July 2015

Twenty‐four strains of marine Roseobacter clade bacteria were isolated from macroalgae and investigated for the production of quorum‐sensing autoinducers, N‐acylhomoserine lactones (AHLs). GC/MS analysis of the extracellular metabolites allowed us to evaluate the release of other small molecules as well. Nineteen strains produced AHLs, ranging from 3‐OH‐C10:0‐HSL (homoserine lactone) to (2E,11Z)‐C18:2‐HSL, but no specific phylogenetic or ecological pattern of individual AHL occurrence was observed when cluster analysis was performed. Other identified compounds included indole, tropone, methyl esters of oligomers of 3‐hydroxybutyric acid, and various amides, such as N‐9‐hexadecenoylalanine methyl ester (9‐C16:1‐NAME), a structural analogue of AHLs. Several compounds were tested for their antibacterial and antialgal activity on marine isolates likely to occur in the habitat of the macroalgae. Both AHLs and 9‐C16:1‐NAME showed high antialgal activity against Skeletonema costatum, whereas their antibacterial activity was low.
BET Inhibition Upregulates SIRT1 and Alleviates Inflammatory Responses
Authors: Kokkola Tarja , Suuronen Tiina , Pesonen Maija , Filippakopoulos Panagis , Salminen Antero , Jarho Elina M. , Lahtela‐Kakkonen Maija
Published: July 2015

Control of histone acetylation is a part of the epigenetic mechanism that regulates gene expression and chromatin architecture. The members of the bromodomain and extra terminal domain (BET) protein family are a group of epigenetic readers that recognize histone acetylation, whereas histone deacetyl‐ ases such as sirtuin 1 (SIRT1) function as epigenetic erasers. We observed that BET inhibition by the specific inhibitor JQ1 upregulated SIRT1 expression and activated SIRT1. Moreover, we observed that BET inhibition functionally reversed the pro‐inflammatory effect of SIRT1 inhibition in a cellular lung disease model. SIRT1 activation is desirable in many age‐related, metabolic and inflammatory diseases; our results suggest that BET protein inhibition would be beneficial in treatment of those conditions. Most importantly, our findings demonstrate a novel mechanism of SIRT1 activation by inhibition of the BET proteins.