bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of acrylic‐based powder coatings with incorporation of montmorillonite clays
Authors: Catarina Gilmar Antônio Santa , Borsoi Cleide , Romanzini Daiane , Piazza Diego , Kunst Sandra Raquel , Scienza Lisete Cristine , Zattera Ademir José 
Published: March 2017

ABSTRACTPowder coatings have been receiving attention because they are environmentally friendly. They do not contain solvents in their composition, and their components have decorative and corrosion‐protection functions, among many others. However, the presence of polymers in their composition increases the risk of combustion in adverse situations. In this context, this study aims to develop and characterize acrylic‐based powder paints with the addition of 2 wt % and 4 wt % montmorillonite clays (MMT) as Cloisite 30B (MMT‐30B) and Cloisite 15A (MTT‐15A), employed as flame retardants. The characterization of the coatings was carried out by thermogravimetric analysis (TGA), X‐ray diffraction, and scanning electron microscopy. After application of the coatings on carbon steel substrates, flammability tests were performed. The coatings with 2 wt % MMT‐30B showed overall better results, especially in the flammability tests. Flames spread less on these coatings than on the other systems. However, when the surface and bottom temperatures were analyzed by the cone calorimeter test, the samples prepared with 4 wt % MMT‐15A were considered safer to be applied in fire scenarios. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45031.
Preparation of a biodegradable poly(vinyl alcohol)–starch composite film and its application in pesticide controlled release
Authors: Wang Song , Jia Zhixin , Zhou Xiangyang , Zhou Dunbai , Chen Mingzhou , Xie Dong , Luo Yuanfang , Jia Demin 
Published: March 2017

ABSTRACTWith the herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D) as a model drug, a series of poly(vinyl alcohol)–starch (PVA–ST) composite films for controlled drug release were prepared by a casting method. The morphology, structure, and release properties were systematically investigated. The results show that when the PVA–ST composite film containing 2,4‐D (PSD) was immersed in water, the drug‐release rate was high, whereas the introduction of sodium montmorillonite (Na‐MMT) and an alginate ion‐crosslinking structure to PSD significantly reduced the release rate and maintained the sustained release of the model drug for a longer period. A leaching experiment through the soil layer showed that the PSD drug‐loaded film with Na‐MMT and the alginate ion‐crosslinking structure (PSDMA) possessed good release properties. The cumulative leached amount of the herbicide 2,4‐D after eight irrigations was reduced to 57.6% from 100%. In addition, the PSDMA film showed favorable mechanical and thermal properties. This composite film is expected to have potential applications in the fields of agriculture, drug delivery, and more. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45051.
Preparation and performance of braid‐reinforced poly(vinyl chloride) hollow fiber membranes
Authors: Liu Hailiang , Wang Shiqian , Mao Jianyue , Xiao Changfa , Huang Qinglin 
Published: March 2017

ABSTRACTA novel braid‐reinforced (BR) poly(vinyl chloride) (PVC) hollow fiber membrane was fabricated via dry‐wet spinning process. The mixtures of PVC polymer solutions were uniformly coated on the tubular braid which contained polyester (PET) and polyacrylonitrile (PAN) fibers. The influences of braid composition on structure and performance of BR PVC hollow fiber membranes were investigated. The results showed that the prepared BR PVC hollow fiber membranes were composed of two layers which contained separation layer and tubular braid supported layer when the PET and PET/PAN hybrid tubular braids were used as the reinforcement. But the sandwich structure appeared when the PAN tubular braid was used as the reinforcement, which revealed outer separation layer, tubular braid supported layer and the inner polymer layer. The BR PVC hollow fiber membranes that prepared by PET/PAN hybrid tubular braid had favorable interfacial bonding state compared with the membrane prepared by pure PET or PAN tubular braid. The pure water flux of the BR PVC hollow fiber membranes that prepared by the PET/PAN hybrid tubular braid were lower than that prepared by pure PET or PAN tubular braid, but the rejection of Bovine serum albumin was opposite. The tensile strength of prepared BR PVC hollow fiber membrane was higher than 50 MPa. Both of the tensile strength and elongation at break decreased with the increase of the PAN filaments in the PET/PAN hybrid tubular braid. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45068.
Development of the Endocrine Pancreas in the Beagle Dog: From Fetal to Adult Life
Authors: Bricout‐Neveu Emilie , Pechberty Severine , Reynaud Karine , Maenhoudt Cindy , José Lecomte Marie , Ravassard Philippe , Czernichow Paul 
Published: March 2017

ABSTRACTOur objectives were to describe, in Beagle dogs, the ontogenesis of beta (insulin‐producing) and alpha (glucagon‐producing) cells from fetal to early postnatal life and adulthood. In addition, to have some insight into interspecies comparison, Beagle dog pancreases were compared to pancreases from a Labrador and Chow Chow. At midgestation, the epithelium was dense, beta cells scarce, and alpha cells numerous and concentrated in the center of the pancreatic bud. From 36 to 45 days post conception (pc), beta cell numbers increased and the epithelium expanded and branched out. At 55 days pc, large beta cell aggregates were seen. At weaning, the islets were similar to those in adults, with limited alpha cells intermingled with numerous beta cells. Quantification of the Alpha to Beta cells ratio has shown a gradual increase of beta cells proportion throughout development. Similar findings were obtained in the two other breeds. In conclusion, in the fetal Beagle dog beta cells emerge from the pancreatic bud at midgestation, but the endocrine structure is mature only in early postnatal life. The ontogenesis of the endocrine pancreas demonstrated in dogs resembles that reported in rats and mice. In contrast, human beta cells appear earlier, at the beginning of the second trimester of gestation. Our study provides a detailed morphological description of pancreatic development in dogs but supplies no information on alpha‐ or beta‐cell function during fetal life. The morphological data reported here provide a foundation for building physiological studies. Anat Rec, 300:1429–1438, 2017. © 2017 Wiley Periodicals, Inc.
Bautechnikgeschichte in Deutschland
Authors: Kurrer Karl‐Eugen , Lorenz Werner 
Published: March 2017

AbstractIn den vergangenen zwei Jahrzehnten hat Bautechnikgeschichte in der deutschen wie in der internationalen Wissenschaftslandschaft auf vielen Ebenen an Gewicht und Prägnanz gewonnen, in Lehre und Forschung ebenso wie in Publikationen, Tagungen und Vortragsreihen. 2004 war ein erster Statusbericht „Construction History in Europe” erschienen, zu dem Karl‐Eugen Kurrer einen Überblick zum Stand und zu den Perspektiven der Bautechnikgeschichte in Deutschland, Österreich und der Schweiz beigetragen hatte. Im Folgenden wird über die disziplinäre Ausdifferenzierung, die institutionelle und personale Verankerung sowie die Forschungsnetzwerke der Bautechnikgeschichte in Deutschland berichtet, die sich seitdem weiterentwickelt haben. Es zeigt sich, dass die Bautechnikgeschichte in ihrer disziplinären Genese zwischenzeitlich die Konstituierungsphase hinter sich gelassen hat und bereits in die Etablierungsphase eingetreten ist.
Dual display of proteins on the yeast cell surface simplifies quantification of binding interactions and enzymatic bioconjugation reactions
Authors: Lim Sungwon , Glasgow Jeff E. , Filsinger Interrante Maria , Storm Erica M. , Cochran Jennifer R. 
Published: March 2017

AbstractYeast surface display, a well‐established technology for protein analysis and engineering, involves expressing a protein of interest as a genetic fusion to either the N‐ or C‐terminus of the yeast Aga2p mating protein. Historically, yeast‐displayed protein variants are flanked by peptide epitope tags that enable flow cytometric measurement of construct expression using fluorescent primary or secondary antibodies. Here, we built upon this technology to develop a new yeast display strategy that comprises fusion of two different proteins to Aga2p, one to the N‐terminus and one to the C‐terminus. This approach allows an antibody fragment, ligand, or receptor to be directly coupled to expression of a fluorescent protein readout, eliminating the need for antibody‐staining of epitope tags to quantify yeast protein expression levels. We show that this system simplifies quantification of protein‐protein binding interactions measured on the yeast cell surface. Moreover, we show that this system facilitates co‐expression of a bioconjugation enzyme and its corresponding peptide substrate on the same Aga2p construct, enabling enzyme expression and catalytic activity to be measured on the surface of yeast.
Engineering oxidative stress defense pathways to build a robust lipid production platform in Yarrowia lipolytica
Authors: Xu Peng , Qiao Kangjian , Stephanopoulos Gregory 
Published: March 2017

ABSTRACTMicrobially derived lipids have recently attracted renewed interests due to their broad applications in production of green diesels, cosmetic additives, and oleochemicals. Metabolic engineering efforts have targeted a large portfolio of biosynthetic pathways to efficiently convert sugar to lipids in oleaginous yeast. In the engineered overproducing strains, endogenous cell metabolism typically generates harmful electrophilic molecules that compromise cell fitness and productivity. Lipids, particularly unsaturated fatty acids, are highly susceptible to oxygen radical attack and the resulting oxidative species are detrimental to cell metabolism and limit lipid productivity. In this study, we investigated cellular oxidative stress defense pathways in Yarrowia lipolytica to further improve the lipid titer, yield, and productivity. Specifically, we determined that coupling glutathione disulfide reductase and glucose‐6‐phosphate dehydrogenase along with aldehyde dehydrogenase are efficient solutions to combat reactive oxygen and aldehyde stress in Y. lipolytica. With the reported engineering strategies, we were able to synchronize cell growth and lipid production, improve cell fitness and morphology, and achieved industrially‐relevant level of lipid titer (72.7 g/L), oil content (81.4%) and productivity (0.97 g/L/h) in controlled bench‐top bioreactors. The strategies reported here represent viable steps in the development of sustainable biorefinery platforms that potentially upgrade low value carbons to high value oleochemicals and biofuels. Biotechnol. Bioeng. 2017;114: 1521–1530. © 2017 Wiley Periodicals, Inc.
Polyclonal and monoclonal IgG binding on protein A resins—Evidence of competitive binding effects
Authors: Weinberg Justin , Zhang Shaojie , Crews Gillian , Healy Edward , Carta Giorgio , Przybycien Todd 
Published: March 2017

ABSTRACTProtein A (ProA) chromatography is used extensively in the biopharmaceutical industry for the selective capture of both polyclonal and monoclonal antibodies (mAbs). This work provides a comparison of the adsorptive behavior of a highly heterogeneous polyclonal hIgG versus that of a mAb as well as the behavior of their mixtures on representative ProA resins. Both pH gradient elution and frontal loading experiments using human polyclonal IgG (hIgG) reveal a distribution of IgG‐ProA binding strengths likely associated with multiple IgG subclasses and the heterogeneity of the variable region. pH gradient analysis of fractions collected along the breakthrough curve demonstrate a clear progression from weaker binding (higher pH eluting) to stronger binding (lower pH eluting) IgG species leaving the column suggesting the possibility of stronger binding species displacing the weaker binding ones. Displacement is directly observed by visualizing the adsorption of fluorescently labeled mAb and hIgG using confocal laser scanning microscopy (CLSM). Here, the displacement of hIgG results in a broad adsorption front compared to the sharp, “shrinking core” behavior typically observed with mAbs. Sequential CLSM adsorption experiments with a mAb and hIgG confirm that stronger or equivalent‐binding hIgG species are able to displace and desorb bound mAb molecules. These phenomena are examined using a variety of ProA resins including CaptivA PriMAB, MabSelect, and MabSelect SuRe to understand the effect of different ligand properties on binding strength and competition among different IgG species. The results of these comparisons suggest that the competition kinetics are slower with ligands that have a single‐point covalent attachment to the base matrix compared to a multi‐point attachment. Biotechnol. Bioeng. 2017;114: 1803–1812. © 2017 Wiley Periodicals, Inc.
Catalytic Dehydration of Fructose into 5‐Hydroxymethylfurfural by a DMSO‐like Polymeric Solid Organocatalyst
Authors: Guo Xiawei , Tang Jinqiang , Xiang Bo , Zhu Liangfang , Yang Huaqing , Hu Changwei 
Published: March 2017

AbstractNovel polymeric solid catalysts, Au@(polythiophene–polythiophene oxides) (Au@PTh–PThOx, x=1–2), are prepared by chemical over‐oxidative polymerization of thiophene in the presence of Au nanoparticles. These organocatalysts show significantly higher activity than their liquid analogs (i.e., DMSO, a frequently‐used solvent and catalyst) for the catalytic dehydration of fructose into 5‐hydroxymethylfurfural (HMF) and exhibit a complete inhibiting effect on HMF rehydration to undesired levulinic acid in low‐boiling solvents. We demonstrate that the sulfoxide (‐SO) group in Au@PTh–PThOx is more active than the sulfone (‐SO2) group, although the formation of the former could be maximized by lowering the concentration of surfactant or improving the concentration of oxidant used in catalyst preparation. The highest HMF yields of 72.6 % and 39.7 % are achieved over Au@PTh–PThO catalyst in 1,4‐dioxane and water, respectively. This catalyst could be completely recycled for use in water without activity loss.
Bimetallic Nickel‐Iridium and Nickel‐Osmium Alloy Nanoparticles and Their Catalytic Performance in Hydrogenation Reactions
Authors: Egeberg Alexander , Dietrich Christine , Kind Christian , Popescu Radian , Gerthsen Dagmar , Behrens Silke , Feldmann Claus 
Published: March 2017

AbstractBimetallic NiIr4 and NiOs4 alloy nanoparticles are prepared and studied with regard to their performance in catalytic hydrogenation reactions. NiIr4 and NiOs4 nanoparticles are obtained by oleylamine‐driven reduction and exhibit mean diameters of (8.9±1.3) and (6.8±1.4) nm at low agglomeration. The phase composition was determined in detail by using different methods, which include high‐resolution TEM, scanning transmission electron microscopy, selected‐area electron diffraction, X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy. This and results in a uniform distribution of both metals Ni‐Ir and Ni‐Os with a ratio of 1:4. The catalytic performance of the NiIr4 and NiOs4 nanoparticles for hydrogenation reactions is evaluated using three selected model substrates: 1‐octene, cinnamaldehyde, and diphenylacetylene. Similar sized Ni, Ir, and Os nanoparticles were used as references. Most remarkable are the excellent selectivity of NiOs4 in the hydrogenation of cinnamaldehyde and the promising formation of (Z)‐stilbene in terms of conversion activity and selectivity. The alloying of Ir and Os with Ni, moreover, is highly cost efficient. In general, both bimetallic alloy nanoparticles, NiIr4 and NiOs4, are shown here for the first time in terms of synthesis, composition, and catalytic hydrogenation.
The Influence of Water on the Performance of Molybdenum Carbide Catalysts in Hydrodeoxygenation Reactions: A Combined Theoretical and Experimental Study
Authors: Engelhardt Jan , Lyu Pengbo , Nachtigall Petr , Schüth Ferdi , García Ángel Morales 
Published: March 2017

AbstractUnderstanding the deactivation of transition‐metal carbide catalysts during hydrodeoxygenation (HDO) reactions is of great importance for improving the production of the second generation fuels from biomass. Based on a combined experimental and theoretical study, we present a mechanistic model for the deactivation of molybdenum carbide catalysts during phenol HDO in the presence of water. At increased water pressure, water molecules preferentially bind to the surface, and active sites are no longer accessible for phenol. In line with first principle calculations, experiments reveal that this process is fully reversible because the reduction of the water partial pressure results in a threefold increase in conversion. The direct deoxygenation of phenol was calculated to be the most favorable pathway, which is governed by the structure of the phenol adsorption complex on the surface at high hydrogen coverage. This is consistent with the experimentally observed high benzene selectivity (85 %) for phenol HDO over MoCx/HCS (hollow carbon spheres) catalyst.
Amperometric Detection of Apoptosis by using p‐Methoxyaniline‐Conjugated Substrate for Caspase‐3
Authors: Sixiang Sun , Inoue Kumi Y. , Shiomoto Shusaku , Takano Shinichiro , Ino Kosuke , Shiku Hitoshi , Matsue Tomokazu 
Published: March 2017

AbstractThis manuscript reports on a novel substrate for the amperometric detection of cellular apoptosis, Asp‐Glu‐Val‐Asp‐p‐methoxyaniline (DEVD‐pMA). This substrate showed electrochemical inertia from −0.2 to 0.7 V versus Ag/AgCl in phosphate‐buffered saline (PBS), but was cleaved by caspase‐3, releasing pMA, which was detected with cyclic voltammetry and chronoamperometry. Compared with p‐aminophenol (pAP), pMA showed lower toxicity to the human hepatocellular carcinoma cell line (HepG2) and higher stability in PBS. By using this substrate, we successfully detected caspase‐3 in the range of 0.31–2.5×10−2 units/mL and cellular apoptosis in HepG2 cells by using simple amperometry without cell lysis. This work will help to develop a simple method for the electrochemical monitoring of apoptosis, which can be applied in biological research and drug development.
A Novel Glucose Biosensor Based on Tb@Mesoporous Metal‐Organic Frameworks/Carbon Nanotube Nanocomposites
Authors: Song Yonghai , Shen Yuan , Gong Coucong , Chen Jingyi , Xu Mengli , Wang Linyu , Wang Li 
Published: March 2017

AbstractThis study demonstrates the exploitation of carbon nanotubes (CNTs) combined with mesoporous metal‐organic frameworks (Tb@mesoMOFs) to form a novel nanocomposite as the platform to construct electrochemical biosensors for glucose detection. Energy‐dispersive X‐ray spectroscopy, UV/Vis spectroscopy, scanning electron microscopy, and electrochemical techniques were used to characterize the Tb@mesoMOFs‐CNT nanocomposites. The results showed that a thin layer of Tb@mesoMOFs uniformly covered the surface of CNTs. The Tb@mesoMOFs‐CNT nanocomposites served as a supporting matrix to load both methylene green (MG) as electron mediators and glucose dehydrogenases (GDH) as electrocatalysts on a glassy carbon electrode (GCE) for constructing an electrochemical glucose biosensor, owing to the large number of micropores of Tb@mesoMOFs and excellent electrical conductivity of the CNTs together with ultrahigh surface area of the nanocomposites. GDH/MG−Tb@MOF‐CNTs/GCE showed good performance for glucose detection with a wide linear range of approximately 25 μM to 17 mM and a low detection limit of 8 μM (R=0.998, n=10). The work also provided a novel idea to prepare excellent MOFs/CNT‐based materials for electrochemical sensing.
Water‐Based Synthesis of Palladium Trigonal Bipyramidal/Tetrahedral Nanocrystals with Enhanced Electrocatalytic Oxidation Activity
Authors: Shang Changshuai , Hong Wei , Guo Yaxiao , Wang Jin , Wang Erkang 
Published: March 2017

AbstractWell‐defined palladium trigonal bipyramidal/tetrahedral nanocrystals were synthesized by an aqueous‐phase hydrothermal method. The final products were a mixture of trigonal bipyramidal and tetrahedral nanocrystals. Statistics indicated that there were more trigonal bipyramids than tetrahedra in the products. Ethylenediamine tetraacetic acid disodium salt (EDTA‐2Na) was proven to be essential in controlling the final shapes of palladium nanocrystals. Some control experiments were also conducted to investigate the shape evolution and formation mechanisms. The synthesized palladium nanocrystals showed enhanced catalytic properties for ethanol and glycerol electrooxidation in alkaline medium. This work provides a new method in preparing Pd nanomaterials with well‐defined shapes.
Ohmic Heating: An Emerging Concept in Organic Synthesis
Authors: Silva Vera L. M. , Santos Luis M. N. B. F. , Silva Artur M. S. 
Published: March 2017

AbstractThe ohmic heating also known as direct Joule heating, is an advanced thermal processing method, mainly used in the food industry to rapidly increase the temperature for either cooking or sterilization purposes. Its use in organic synthesis, in the heating of chemical reactors, is an emerging method that shows great potential, the development of which has started recently. This Concept article focuses on the use of ohmic heating as a new tool for organic synthesis. It presents the fundamentals of ohmic heating and makes a qualitative and quantitative comparison with other common heating methods. A brief description of the ohmic reactor prototype in operation is presented as well as recent examples of its use in organic synthesis at laboratory scale, thus showing the current state of the research. The advantages and limitations of this heating method, as well as its main current applications are also discussed. Finally, the prospects and potential implications of ohmic heating in future research in chemical synthesis are proposed.
The Effects of Macromolecular Crowding on Calmodulin Structure and Function
Authors: Xu Guohua , Zhao Jiajing , Cheng Kai , Wu Qiong , Liu Xiaoli , Liu Maili , Li Conggang 
Published: March 2017

AbstractMacromolecular crowding and confinement are two factors that potentially affect protein structure and function in a complex cellular environment. The confinement effect on the structure and function of holoCaM [Ca2+‐loaded calmodulin (CaM)], a two‐domain protein involved in many calcium‐mediated signaling pathways, has been investigated previously. However, little is known about how macromolecular crowding affects holoCaM structure and function. Here, the structure–function correlations of holoCaM are investigated in macromolecular crowded environments. It was found that macromolecular crowding impacts its structure and function mildly. The major conformational states are still extended conformation with inter‐domain separation in crowded environment as well as those in dilute solution, but the population of transiently compact conformation increases compared to dilute solution. Furthermore, macromolecular crowding facilitates the binding of CaM with AcN19 peptide (CaM‐bind domain of α‐syn). This study provides a direct comparison for macromolecular crowding and confinement effects on protein structure and function, which helps to understand chemistry regulation in living cells.