bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing Large Strain Elasticity of Brittle Elastomeric Networks by Embedding Them in a Soft Extensible Matrix
Authors: Ducrot Etienne , Creton Costantino
Published: February 2016

Here, the general design and properties of new multiple network elastomers with an exceptional combination of stiffness, toughness, and elasticity are reported. In this paper, it is reported in more detail how the increase in strain at break resulting from the toughening can be used to provide great insight in the large strain properties of otherwise brittle acrylic well crosslinked networks. The networks have been prepared by sequences of polymerization and swelling with monomers. The parameters that have been varied are the nature of the base monomers and the degree of crosslinking of the first network. Here, the small strain properties, equilibrium swelling, and large strain properties in uniaxial tension are characterized. It is shown here that the large strain properties of the multiple networks are quantitatively controlled by the large strain properties of the stretched first network which acts as a percolating filler, while the small and intermediate properties are controlled by the entanglement density which can be largely superior to that of homogeneous networks.
Multifunctional Quantum Dot Nanoparticles for Effective Differentiation and Long‐Term Tracking of Human Mesenchymal Stem Cells In Vitro and In Vivo
Authors: Li Jinming , Lee Wayne Yukwai , Wu Tianyi , Xu Jianbin , Zhang Kunyu , Li Gang , Xia Jiang , Bian Liming
Published: February 2016

Human mesenchymal stem cells (hMSCs) hold great potential for regenerative medicine. Efficient induction of hMSC differentiation and better understanding of hMSCs behaviors in vitro and in vivo are essential to the clinical translation of stem cell therapy. Here a quantum dots (QDs)‐based multifunctional nanoparticle (RGD‐β‐CD‐QDs) is developed for effective enhancing differentiation and long‐term tracking of hMSCs in vitro and in vivo. The RGD‐β‐CD‐QDs are modified with β‐cyclodextrin (β‐CD) and Cys‐Lys‐Lys‐Arg‐Gly‐Asp (CKKRGD) peptide on the surface. The β‐CD can harbor hydrophobic osteogenic small molecule dexamethasone (Dex) and the RGD peptide not only facilitates the complexation of siRNA and delivers siRNA into hMSCs but also leads to cellular uptake of nanoparticles by RGD receptor. Co‐delivery of Dex and siRNA by RGD‐β‐CD‐QDs nanocarrier significantly expedites and enhances the osteogenesis differentiation of hMSCs in vitro and in vivo by combined effect of small molecule and RNAi. Furthermore, the RGD‐β‐CD‐QDs can be labeled with hMSCs for a long‐term tracking (3 weeks) in vivo to observe the behaviors of implanted hMSCs in animal level. These findings demonstrate that the RGD‐β‐CD‐QDs nanocarrier provides a powerful tool to simultaneously enhance differentiation and long‐term tracking of hMSCs in vitro and in vivo for regenerative medicine.
Differentiation Induction of Mouse Neural Stem Cells in Hydrogel Tubular Microenvironments with Controlled Tube Dimensions
Authors: Onoe Hiroaki , Kato‐Negishi Midori , Itou Akane , Takeuchi Shoji
Published: February 2016

In this paper, a tubular 3D microenvironment created in a calcium alginate hydrogel microtube with respect to the effect of scaffold dimensions on the differentiation of mouse neuronal stem cells (mNSCs) is evaluated. Five types of hydrogel microtubes with different core diameters (≈65–200 μm) and shell thicknesses (≈30–110 μm) are fabricated by using a double coaxial microfluidic device, and differentiation of encapsulated mNSCs is induced by changing the growth medium to the differentiation medium. The influence of the microtube geometries is examined by using quantitative real‐time polymerase chain reaction and fluorescent immunocytochemistry. The analyses reveal that differences in microtube thickness within 30–110 μm affected the relative Tuj1 expression but do not affect the morphology of encapsulated mNSCs. The diameters of cores influence both the relative Tuj1 expression and morphology of the differentiated neurons. It is found that the tubular microenvironment with a core diameter of less than ≈100 μm contributes to forming highly viable and aligned neural tissue. The tubular microenvironment can provide an effective method for constructing microfiber‐shaped neural tissues with geometrically controlled differentiation induction.
Ethanol perm‐selective B‐ZSM‐5 zeolite membranes from dilute solutions
Authors: Chai Lijun , Yang Jianhua , Lu Jinming , Yin Dehong , Zhang Yan , Wang Jinqu
Published: February 2016

Boron‐substituted MFI (B‐ZSM‐5) zeolite membranes with high pervaporation (PV) performance were prepared onto seeded inexpensive macroporous α‐Al2O3 supports from dilute solution and explored for the separation of ethanol/water mixtures by PV. The effects of several parameters on microstructures and PV performance of the B‐ZSM‐5 membranes were examined systematically, including the seed size, synthesis temperature, crystallization time, B/Si ratio, H2O/SiO2 ratio and silica source. A continuous and compact B‐ZSM‐5 membrane was fabricated from solution containing 1 tetraethyl orthosilicate/0.2 tetrapropylammonium hydroxide/0.06 boric acid/600 H2O at 448 K for 24 h, showing a separation factor of 55 and a flux of 2.6 kg/m2 h along with high reproducibility for a 5 wt % ethanol/water mixture at 333 K. It was demonstrated that the incorporation of boron into mobile five (MFI) structure could increase the hydrophobicity of B‐ZSM‐5 membrane evidenced by the improved contact angle and amount of the adsorbed ethanol, and thus enhance the PV property for ethanol/water mixtures. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2447–2458, 2016
Ein Netzwerk aus hydrophoben Tunneln zum Transport gasförmiger Reaktanten in einer O2‐toleranten, membrangebundenen [NiFe]‐ Hydrogenase, aufgedeckt durch Derivatisierung mit Krypton
Authors: Kalms Jacqueline , Schmidt Andrea , Frielingsdorf Stefan , van der Linden Peter , von Stetten David , Lenz Oliver , Carpentier Philippe , Scheerer Patrick
Published: February 2016

[NiFe]‐Hydrogenasen katalysieren die reversible heterolytische Spaltung von Wasserstoff in Protonen und Elektronen. Das tief im Protein liegende aktive Zentrum wird dabei von gasförmigen Substraten und Inhibitoren über Tunnel erreicht. Hier wird die Proteinstruktur der O2‐toleranten, membrangebundenen [NiFe]‐Hydrogenase von Ralstonia eutropha (ReMBH) anhand von Proteinkristallen beschrieben, die mit Krypton derivatisiert wurden. Die Positionen der Kryptonatome ermöglichen eine umfassende Beschreibung des Gastunnelnetzwerks. Eine detaillierte Übersicht von Größe, Länge und Route der Tunnel wurde mithilfe von Rechnungen erstellt. Vergleicht man die Tunneleigenschaften der ReMBH mit Kristallstrukturen anderer O2‐toleranter und O2‐sensitiver [NiFe]‐Hydrogenasen hinsichtlich der Größe und Anzahl der hydrophoben Gastunnel, ergeben sich wesentliche Unterschiede zwischen beiden Gruppen. Einige sind womöglich auf die bemerkenswerte Eigenschaft der Sauerstofftoleranz zurückzuführen.
Fast and Tight Boronate Formation for Click Bioorthogonal Conjugation
Authors: Akgun Burcin , Hall Dennis G.
Published: February 2016

A new click bioorthogonal reaction system was devised to enable the fast ligation (kON≈340 m−1 s−1) of conjugatable derivatives of a rigid cyclic diol (nopoldiol) and a carefully optimized boronic acid partner, 2‐methyl‐5‐carboxymethylphenylboronic acid. Using NMR and fluorescence spectroscopy studies, the corresponding boronates were found to form reversibly within minutes at low micromolar concentration in water, providing submicromolar equilibrium constant (Keq≈105–106 m−1). Efficient protein conjugation under physiological conditions was demonstrated with model proteins thioredoxin and albumin, and characterized by mass spectrometry and gel electrophoresis.
Formation of Ultrathin, Continuous Metal–Organic Framework Membranes on Flexible Polymer Substrates
Authors: Hou Jingwei , Sutrisna Putu D. , Zhang Yatao , Chen Vicki
Published: February 2016

Metal–organic framework (MOF) materials have an enormous potential in separation applications, but to realize their potential as semipermeable membranes they need to be assembled into thin continuous macroscopic films for fabrication into devices. By using a facile immersion technique, we prepared ultrathin, continuous zeolitic imidazolate framework (ZIF‐8) membranes on titania‐functionalized porous polymeric supports. The coherent ZIF‐8 layer was surprisingly flexible and adhered well to the support, and the composite membrane could sustain bending and elongation. The membranes exhibited molecular sieving behavior, close to the theoretical permeability of ZIF‐8, with hydrogen permeance up to 201×10−7 mol m−2 s−1 Pa−1 and an ideal H2/CO2 selectivity of 7:1. This approach offers significant opportunities to exploit the unique properties of MOFs in the fabrication of separation and sensing devices.
Organocatalysis by Networks of Cooperative Hydrogen Bonds: Enantioselective Direct Mannich Addition to Preformed Arylideneureas
Authors: Lillo Victor J. , Mansilla Javier , Saá José M.
Published: February 2016

The concept of noncovalent organocatalysis by means of networks of cooperative hydrogen bonds (NCHB organocatalysis) has been explored. Arylideneureas were chosen as ideal substrates because of their powerful donor–acceptor properties. We have examined their uncatalyzed, direct Mannich reaction with acetoacetates in comparison with that catalyzed by a number of salan derivatives capable of providing a network of cooperative hydrogen bonds. Catalyst D [(R,R)‐N,N′‐bis(salicyl)cyclohexane‐1,2‐diamine] was found to drive the above direct Mannich reaction in an enantioselective manner, thereby allowing the synthesis of several Biginelli dihydropyrimidinones with high enantioselectivity. DFT calculations (B3LYP‐D‐PCM/6‐31+G*//B3LYP/6‐31+G*) revealed that the NCHB organocatalyst lowers the energy barrier of the reaction. The NCHB organocatalysts appear to function as biomimetic catalysts.
The Origin of Ultralow Thermal Conductivity in InTe: Lone‐Pair‐Induced Anharmonic Rattling
Authors: Jana Manoj K. , Pal Koushik , Waghmare Umesh V. , Biswas Kanishka
Published: February 2016

Understanding the origin of intrinsically low thermal conductivity is fundamentally important to the development of high‐performance thermoelectric materials, which can convert waste‐heat into electricity. Herein, we report an ultralow lattice thermal conductivity (ca. 0.4 W m−1 K−1) in mixed valent InTe (that is, In+In3+Te2), which exhibits an intrinsic bonding asymmetry with coexistent covalent and ionic substructures. The phonon dispersion of InTe exhibits, along with low‐energy flat branches, weak instabilities associated with the rattling vibrations of In+ atoms along the columnar ionic substructure. These weakly unstable phonons originate from the 5s2 lone pair of the In+ atom and are strongly anharmonic, which scatter the heat‐carrying acoustic phonons through strong anharmonic phonon–phonon interactions, as evident in anomalously high mode Grüneisen parameters. A maximum thermoelectric figure of merit (z T) of about 0.9 is achieved at 600 K for the 0.3 mol % In‐deficient sample, making InTe a promising material for mid‐temperature thermoelectric applications.
Duale genetische Kodierung von Acetyllysin und nicht‐hydrolysierbarem Thioacetyllysin mittels Flexizym
Authors: Xiong Hai , Reynolds Noah M. , Fan Chenguang , Englert Markus , Hoyer Denton , Miller Scott J. , Söll Dieter
Published: February 2016

Die Acetylierung von Lysin‐Bausteinen ist eine wichtige posttranslationale Proteinmodifikation. Die Lysin‐Acetylierung in Histonproteinen und deren Interaktion mit anderen posttranslationalen Modifikationen in Histon‐ und nicht‐Histon‐Proteinen ist essentiell bei der DNA‐Replikation, DNA‐Reparatur und Transkriptionsregulation. Wir verwendeten die Flexizym‐Technologie, um die Aminosäuren Acetyllysin (AcK) und nicht‐hydrolysierbares Thioacetyllysin (ThioAcK) in vitro in intakte Proteine einzubauen. ThioAcK und AcK wurden in humanes Histon H3 positionsspezifisch inkorporiert. Dies erfolgte entweder individuell oder paarweise bei verschiedenen Lysin‐Positionen innerhalb des humanen Histon H3. Die Thioacetylgruppe im Histon H3 konnte nicht durch die Histon‐Deacetylase Sirtuin (Typ 1) abgespalten werden, wie durch diese Studie gezeigt wurde. Diese Methode des AcK‐ und ThioAcK‐Einbaus stellt ein wichtiges Werkzeug für die Untersuchung der Protein‐Acetylierung sowie deren Rolle in der Interaktion mit weiteren posttranlationalen Modifizierungen dar.
Functional Organosulfide Electrolyte Promotes an Alternate Reaction Pathway to Achieve High Performance in Lithium–Sulfur Batteries
Authors: Chen Shuru , Dai Fang , Gordin Mikhail L. , Yu Zhaoxin , Gao Yue , Song Jiangxuan , Wang Donghai
Published: February 2016

Lithium–sulfur (Li‐S) batteries have recently received great attention because they promise to provide energy density far beyond current lithium ion batteries. Typically, Li‐S batteries operate by conversion of sulfur to reversibly form different soluble lithium polysulfide intermediates and insoluble lithium sulfides through multistep redox reactions. Herein, we report a functional electrolyte system incorporating dimethyl disulfide as a co‐solvent that enables a new electrochemical reduction pathway for sulfur cathodes. This pathway uses soluble dimethyl polysulfides and lithium organosulfides as intermediates and products, which can boost cell capacity and lead to improved discharge–charge reversibility and cycling performance of sulfur cathodes. This electrolyte system can potentially enable Li‐S batteries to achieve high energy density.
Turn‐On Luminescent Probes for the Real‐Time Monitoring of Endogenous Hydroxyl Radicals in Living Cells
Authors: Zhou Wenjuan , Cao Yuqing , Sui Dandan , Lu Chao
Published: February 2016

The utilization of semiconductor quantum dots (QDs) as optical labels for biosensing and biorecognition has made substantial progress. However, the development of a suitable QD‐based luminescent probe that is capable of detecting individual reactive oxygen species (ROS) represents a great challenge, mainly because the fluorescence of QDs is quenched by a wide variety of ROS. To overcome this limitation, a novel QD‐based turn‐on luminescent probe for the specific detection of .OH has been designed, and its application in monitoring the endogenous release of .OH species in living cells is demonstrated. Metal citrate complexes on the surfaces of the QDs can act as electron donors, injecting electrons into the LUMO of the QDs, while .OH can inject holes into the HOMO of the QDs. Accordingly, electron–hole pairs are produced, which could emit strong luminescence by electron–hole recombination. Importantly, this luminescent probe does not respond to other ROS.
Bio‐Inspired Renewable Surface‐Initiated Polymerization from Permanently Embedded Initiators
Authors: Du Tao , Li Bin , Wang Xiaolong , Yu Bo , Pei Xiaowei , Huck Wilhelm T. S. , Zhou Feng
Published: February 2016

Herein, we describe a simple and robust approach to repeatedly modify surfaces with polymer brushes through surface‐initiated atomic transfer radical polymerization (SI‐ATRP), based on an initiator‐embedded polystyrene sheet that does not rely on specific surface chemistries for initiator immobilization. The surface‐grafted polymer brushes can be wiped away to expose fresh underlying initiator that re‐initiates polymerization. This strategy provides a facile route for modification of molded or embossed surfaces, with possible applications in the preparation of fluidic devices and polymer‐embedded circuits.
Structural Revisions of a Class of Natural Products: Scaffolds of Aglycon Analogues of Fusicoccins and Cotylenins Isolated from Fungi
Authors: Tang Ying , Xue Yongbo , Du Guang , Wang Jianping , Liu Junjun , Sun Bin , Li Xiao‐Nian , Yao Guangmin , Luo Zengwei , Zhang Yonghui
Published: February 2016

The reisolation and structural revision of brassicicene D is described, and inspired us to reassign the core skeletons of brassicicenes C–H, J and K, ranging from dicyclopenta[a,d]cyclooctane to tricyclo[9.2.1.03,7]tetradecane using quantum‐chemical predictions and experimental validation strategies. Three novel, highly modified fusicoccanes, brassicicenes L–N, were also isolated from the fungus Alternaria brassicicola, and their structures were unequivocally established by spectroscopic data, ECD calculations, and crystallography. The reassigned structures represent the first class of bridgehead double‐bond‐containing natural products with a bicyclo[6.2.1]undecane carbon skeleton. Furthermore, their stabilities were first predicted with olefin strain energy calculations. Collectively, these findings extend our view of the application of computational predictions and biosynthetic logic‐based structure elucidation to address problems related to the structure and stability of natural products.
Anion–π Catalysis of Enolate Chemistry: Rigidified Leonard Turns as a General Motif to Run Reactions on Aromatic Surfaces
Authors: Cotelle Yoann , Benz Sebastian , Avestro Alyssa‐Jennifer , Ward Thomas R. , Sakai Naomi , Matile Stefan
Published: February 2016

To integrate anion–π, cation–π, and ion pair–π interactions in catalysis, the fundamental challenge is to run reactions reliably on aromatic surfaces. Addressing a specific question concerning enolate addition to nitroolefins, this study elaborates on Leonard turns to tackle this problem in a general manner. Increasingly refined turns are constructed to position malonate half thioesters as close as possible on π‐acidic surfaces. The resulting preorganization of reactive intermediates is shown to support the disfavored addition to enolate acceptors to an absolutely unexpected extent. This decisive impact on anion–π catalysis increases with the rigidity of the turns. The new, rigidified Leonard turns are most effective with weak anion–π interactions, whereas stronger interactions do not require such ideal substrate positioning to operate well. The stunning simplicity of the motif and its surprisingly strong relevance for function should render the introduced approach generally useful.
Selective Alkane Oxidation by Manganese Oxide: Site Isolation of MnOx Chains at the Surface of MnWO4 Nanorods
Authors: Li Xuan , Lunkenbein Thomas , Pfeifer Verena , Jastak Mateusz , Nielsen Pia Kjaer , Girgsdies Frank , Knop‐Gericke Axel , Rosowski Frank , Schlögl Robert , Trunschke Annette
Published: February 2016

The electronic and structural properties of vanadium‐containing phases govern the formation of isolated active sites at the surface of these catalysts for selective alkane oxidation. This concept is not restricted to vanadium oxide. The deliberate use of hydrothermal techniques can turn the typical combustion catalyst manganese oxide into a selective catalyst for oxidative propane dehydrogenation. Nanostructured, crystalline MnWO4 serves as the support that stabilizes a defect‐rich MnOx surface phase. Oxygen defects can be reversibly replenished and depleted at the reaction temperature. Terminating MnOx zigzag chains on the (010) crystal planes are suspected to bear structurally site‐isolated oxygen defects that account for the unexpectedly good performance of the catalyst in propane activation.
Werner Complexes with ω‐Dimethylaminoalkyl Substituted Ethylenediamine Ligands: Bifunctional Hydrogen‐Bond‐Donor Catalysts for Highly Enantioselective Michael Additions
Authors: Ghosh Subrata K. , Ganzmann Carola , Bhuvanesh Nattamai , Gladysz John A.
Published: February 2016

The racemic carbonate complex [Co(en)2O2CO]+ Cl− (en=1,2‐ethylenediamine) and (S)‐[H3NCH((CH2)nNHMe2)CH2NH3]3+ 3 Cl− (n=1–4) react (water, charcoal, 100 °C) to give [Co(en)2((S)‐H2NCH((CH2)nNHMe2)CH2NH2)]4+ 4 Cl− (3 a–d H4+ 4 Cl−) as a mixture of Λ/Δ diastereomers that separate on chiral‐phase Sephadex columns. These are treated with NaOH/Na+ BArf− (BArf=B(3,5‐C6H3(CF3)2)4) to give lipophilic Λ‐ and Δ‐3 a–d3+ 3 BArf−, which are screened as catalysts (10 mol %) for additions of dialkyl malonates to nitroalkenes. Optimal results are obtained with Λ‐3 c3+ 3 BArf− (CH2Cl2, −35 °C; 98–82 % yields and 99–93 % ee for six β‐arylnitroethenes). The monofunctional catalysts Λ‐ and Δ‐[Co(en)3]3+ 3 BArf− give enantioselectivities of <10 % ee with equal loadings of Et3N. The crystal structure of Δ‐3 a H4+ 4 Cl− provides a starting point for speculation regarding transition‐state assemblies.
Ligand‐Enabled Arylation of γ‐C−H Bonds
Authors: Li Suhua , Zhu Ru‐Yi , Xiao Kai‐Jiong , Yu Jin‐Quan
Published: February 2016

PdII‐catalyzed arylation of γ‐C(sp3)−H bonds of aliphatic acid‐derived amides was developed by using quinoline‐based ligands. Various γ‐aryl‐α‐amino acids were prepared from natural amino acids using this method. The influence of ligand structure on reactivity was also systematically investigated.
Nucleophilic Reactivity of a Nitride‐Bridged Diuranium(IV) Complex: CO2 and CS2 Functionalization
Authors: Falcone Marta , Chatelain Lucile , Mazzanti Marinella
Published: February 2016

Thermolysis of the nitride‐bridged diuranium(IV) complex Cs{(μ‐N)[U(OSi(OtBu)3)3]2} (1) showed that the bridging nitride behaves as a strong nucleophile, promoting N−C bond formation by siloxide ligand fragmentation to yield an imido‐bridged siloxide/silanediolate diuranium(IV) complex, Cs{(μ‐NtBu)(μ‐O2Si(OtBu)2)U2(OSi(OtBu)3)5}. Complex 1 displayed reactivity towards CS2 and CO2 at room temperature that is unprecedented in f‐element chemistry, affording diverse N‐functionalized products depending on the reaction stoichiometry. The reaction of 1 with two equivalents of CS2 yielded the thiocyanate/thiocarbonate complex Cs{(μ‐NCS)(μ‐CS3)[U(OSi(OtBu)3)3]2} via a putative NCS−/S2− intermediate. The reaction of 1 with one equivalent of CO2 resulted in deoxygenation and N−C bond formation, yielding the cyanate/oxo complex Cs{(μ‐NCO)(μ‐O)[U(OSi(OtBu)3)3]2}. Addition of excess CO2 to 1 led to the unprecedented dicarbamate product Cs{(μ‐NC2O4)[U(OSi(OtBu)3)3]2}.
Crystal‐Structure‐Guided Design of Self‐Assembling RNA Nanotriangles
Authors: Boerneke Mark A. , Dibrov Sergey M. , Hermann Thomas
Published: February 2016

RNA nanotechnology uses RNA structural motifs to build nanosized architectures that assemble through selective base‐pair interactions. Herein, we report the crystal‐structure‐guided design of highly stable RNA nanotriangles that self‐assemble cooperatively from short oligonucleotides. The crystal structure of an 81 nucleotide nanotriangle determined at 2.6 Å resolution reveals the so‐far smallest circularly closed nanoobject made entirely of double‐stranded RNA. The assembly of the nanotriangle architecture involved RNA corner motifs that were derived from ligand‐responsive RNA switches, which offer the opportunity to control self‐assembly and dissociation.
Gel structure phase behavior in micro nanofibrillated cellulose containing in situ precipitated calcium carbonate
Authors: Dimic‐Misic Katarina , Rantanen Juuso , Maloney Thad C. , Gane Patrick A. C.
Published: February 2016

Speciality high‐strength board, packaging grades, and novel cellulose‐based nanocomposites may incorporate microcellulosic nanofibrillated materials (MNFC), although the rheological properties of such strongly water sorbing structures are challenging for processing technologies. This study introduces rheological methods for the evaluation of dewatering and flow behavior of such high consistency furnishes to exemplify the effect of energy input on microfibrillar material (MFC), as produced by a combination of enzymatic pretreatment and increased levels of fluidization. The large number of fibril contact points act to entrap water, held both on the fibril surface as immobilized water and in the interfibril spacing forming the gel structure. Tuning of the rheological and dewatering properties has been enabled by in situ precipitation of calcium carbonate filler (in situ PCC) on the MFC, which results in the production of a more uniform furnish. Such in situ PCC coated MFC fibrils incorporated into furnish were seen to increase dewatering rate over that of the furnish mix without the in situ precipitated filler primarily because of the reduction in total surface area of the fibers and fibrils when the pigment is present on the fibrillary surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43486.
Proton exchange membrane based on crosslinked sulfonated polyphosphazene containing pendent perfluorosulfonic acid groups with sulfonated poly(ether ether ketone)
Authors: Dong Yan , Zhang Yan‐Xia , Xu Hu‐Lin , Luo Tian‐Wei , Fu Feng‐Yan , Zhu Chang‐Jin
Published: February 2016

A series of crosslinked membranes based on new sulfonated polyphosphazene bearing pendent perfluorosulfonic acid groups (PMFP‐g‐PS) and sulfonated poly (ether ether ketone) were prepared and evaluated as proton exchange membranes for direct methanol fuel cells (DMFCs). The structure of PMFP‐g‐PS was characterized by Fourier transform infrared spectroscopy,1H and19F NMR spectra. In comparison with the pristine PMFP‐g‐PS membrane, the crosslinked membranes showed improved water uptakes and proton conductivities. The methanol permeability values of the membranes were in the range of 1.32 × 10−7to 3.85 × 10−7cm2/s, which were lower than Nafion 117 (12.1 × 10−7cm2/s). The selectivity of all the membranes was much higher compared with Nafion 117. Furthermore, transmission electron microscopy observation revealed that clear phase‐separated structures were well dispersed and connected to each other in the membranes. These membranes displayed high water uptakes and low swelling ratios, high proton conductivities, low methanol permeability values, good thermal, and oxidative stabilities. The results indicate that these membranes are potential candidate proton exchange membrane materials for DMFCs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 43492.
Preparation of highly concentrated inverse emulsions of acrylamide‐based anionic copolymers as efficient water rheological modifiers
Authors: González Rivera José , Hernández Barajas José , Gutiérrez Carrillo Atilano , Aguilera Alvarado Alberto F.
Published: February 2016

Highly concentrated inverse anionic polymeric emulsions (with a solid content of up to 63 wt %) were prepared using a two‐step methodology: (i) First, acrylamide, acrylic acid, and its ammonium salts crosslinked copolymers were obtained by inverse emulsion polymerization, (ii) The water/volatile oil mixture was then separated from the heterogeneous system by vacuum distillation. To maintain sufficient stability during the reaction and distillation processes, a ternary surfactant mixture was used. A surface response methodology was employed to obtain the optimal values of the factors involved in both process and product specifications, and to maximize the high performance of these inverse anionic polymer emulsions. This yielded a product containing up to 63.2 wt % solids capable of achieving Brookfield viscosities as high as 40.3 Pa·s, using an aliquote of these concentrated inverse polymer emulsions (1.8 wt % in deionized water). Rheological characterization (oscillatory and rotational measurements) was carried out to evaluate the behavior of the diluted inverse anionic polymer emulsion in water thickening. The methodology developed can be used to formulate a wide range of viscoelastic (G″/G′) water‐based products from anionic water soluble polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43502.
Solvent‐free synthesis of polyols from 1‐butene metathesized palm oil for use in polyurethane foams
Authors: Pillai Prasanth K. S. , Li Shaojun , Bouzidi Laziz , Narine Suresh S.
Published: February 2016

Green Polyols were synthesized from a 1‐butene cross metathesized palm oil (PMTAG) using a green, solvent free epoxidation and hydroxylation pathway. The synthetic strategy was adapted to control the degree of double bond epoxidation and ultimately the hydroxyl value of the polyols. The polyols comprised diol and tetrol monomers with terminal hydroxyl groups content as high as ∼18 mol %, and achieved hydroxyl values between 83 and 119 mg KOH g−1. Functional Rigid and highly flexible foams were prepared from two designer Green Polyols. The foams presented a high thermal stability (Ton of degradation of ∼270 °C), suitable glass transition temperatures (∼−12 °C and ∼50 °C) and compressive strength (0.21 MPa at 10% strain and ∼1 MPa at 10% strain for the flexible and rigid foams, respectively) which are superior to existing lipid‐based counterparts. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43509.
Ionic conductivity and dielectric behavior of novel poly(vinyl formal)‐based single‐ion‐conductor polymer electrolytes
Authors: Guan Hong‐Yan , Guo Zhong‐Bao , Ding Jian‐Jun , Lian Fang
Published: February 2016

Novel single‐ion‐conductor polymer (SCP) electrolytes based on oxalate‐chelated‐borate‐structure‐grafted poly(vinyl formal) (PVFM) were synthesized via a solution casting technique. The influence of the molar ratio of OH and boron atoms in PVFM on the ionic conductivity (σ) of the SCP electrolytes at different temperatures was investigated with alternating‐current impedance spectroscopy in the frequency range of 0.01 Hz to 1 MHz. The results show that σ of the SCP electrolytes at 15–60 °C was about 10−6–10−5 S/cm, and temperature dependence of the conductivity of the electrolytes followed the Vogel–Tamman–Fulcher relationship. The dielectric behaviors of the SCP electrolytes were analyzed in view of the dielectric permittivity and dielectric modulus of the electrolytes. Dielectric analysis revealed that the transport of Li+ ions in the PVFM‐based SCP electrolytes mainly followed a hopping mechanism coupled with the segmental motion of the polymer chain. Additionally, a dielectric relaxation was found in the high‐frequency region; this was a thermally activated result and also implied the appearance of carrier hopping. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43510.
Changes in tropical cyclone activity offset the ocean surface warming in northwest Pacific: 1981–2014
Authors: June Chang Chiung‐Wen , Simon Wang S.‐Y. , Hsu Huang‐Hsiung
Published: February 2016

Tropical cyclones (TCs) leave a cold wake in the sea surface temperature (SST). In the northwest Pacific, TC activity and SST have both increased since the 1980s, but the extent to which ocean surface warming is affected by the changing TC activity is unknown. Analysis of the 1981–2014 period indicates that the intensified effect of TC cold wakes has offset the SST warming trend by 37% during the typhoon season, implying that the observed SST warming might be underestimated. This factor could affect long‐term climate simulations that are forced with prescribed SST.
An indole‐deficient Escherichia coli strain improves screening of cytochromes P450 for biotechnological applications
Authors: Brixius‐Anderko Simone , Hannemann Frank , Ringle Michael , Khatri Yogan , Bernhardt Rita
Published: February 2016

Escherichia coli has developed into an attractive organism for heterologous cytochrome P450 production, but, in some cases, was restricted as a host in view of a screening of orphan cytochromes P450 or mutant libraries in the context of molecular evolution due to the formation of the cytochrome P450 inhibitor indole by the enzyme tryptophanase (TnaA). To overcome this effect, we disrupted the tnaA gene locus of E. coli C43(DE3) and evaluated the new strain for whole‐cell substrate conversions with three indole‐sensitive cytochromes P450, myxobacterial CYP264A1, and CYP109D1 as well as bovine steroidogenic CYP21A2. For purified CYP264A1 and CYP21A2, the half maximal inhibitory indole concentration was determined to be 140 and 500 μM, which is within the physiological concentration range occurring during cultivation of E. coli in complex medium. Biotransformations with C43(DE3)_∆tnaA achieved a 30% higher product formation in the case of CYP21A2 and an even fourfold increase with CYP264A1 compared with C43(DE3) cells. In whole‐cell conversion based on CYP109D1, which converts indole to indigo, we could successfully avoid this reaction. Results in microplate format indicate that our newly designed strain is a suitable host for a fast and efficient screening of indole‐influenced cytochromes P450 in complex medium.
Priming Risky Choice: Do Risk Preferences Need Inferences?
Authors: Newell Ben R. , Shaw Brad
Published: February 2016

The notion that subtle influences, often falling outside awareness, can bias behaviour has a strong grip on both theoretical perspectives and the public imagination. We report three experiments that examined this idea in the context of risky choice. Experiment 1 (N = 100) appeared to find evidence for an interaction whereby participants primed but not reminded of the prime showed an assimilation effect (e.g. participants primed to be risk seeking became more risk seeking) whereas those who were primed and reminded showed a contrast effect (e.g. became less risk seeking). However, two further experiments (N = 180, N = 128) failed to find any evidence for this interaction, and none of the experiments found evidence for the asymmetry in awareness predicted by an ‘unconscious’ assimilation but ‘conscious’ contrast account. The data were analysed using both Null Hypothesis Significance Testing and Bayesian methods, and the implications of the conclusions arising from each are discussed. Whatever one's statistical predilection, the results imply a reduction of confidence in the belief that risk preferences need no inferences. Copyright © 2016 John Wiley & Sons, Ltd.
Effect of UV irradiation on different types of luminescence of SrAl2O4:Eu,Dy phosphors
Authors: Jha Piyush
Published: February 2016

This paper reports the luminescence behavior of Sr0.097Al2O4:Eu0.01,Dy0.02 phosphors under UV‐irradiation. The effect of UV‐irradiation on afterglow (AG), thermoluminescence (TL) and mechanoluminescence (ML) of Sr0.097Al2O4:Eu0.01,Dy0.02 phosphors is investigated. The space group of Sr0.097Al2O4:Eu0.01,Dy0.02 phosphors is monoclinic P21. The prepared phosphors exhibit a long AG, intense TL and ML. It is found that the AG, ML intensity and TL increase with increasing duration of irradiation time. The ML intensity decreases with successive impact of the load onto the phosphors, whereby the diminished ML intensity can be recovered by UV‐irradiation. Copyright © 2016 John Wiley & Sons, Ltd.
Luminescence in Ba2Sr2Al2O7:RE (RE = Tb3+,Eu3+andDy3+) novel aluminate phosphors
Authors: Pardhi S. A. , Panse V. R. , Dhoble S. J.
Published: February 2016

The luminescence of novel rare earth (Tb3+, Eu3+ and Dy3+)‐activated Ba2Sr2Al2O7 phosphors for solid‐state lighting is presented. The aluminate phosphors were synthesized using a one‐step combustion method. X‐Ray diffraction, scanning electron microscopy and photoluminescence characterizations were performed to understand the mechanism of excitation and the corresponding emission in the as‐prepared phosphor, as characterized the phase purity and microstructure. Improvements in the luminescence properties of the phosphors with rare earth concentration were observed. The phosphor hue could be tuned from blue, green and red by proper selection of rare earth ions in typical concentrations. Effective absorption in the near‐ultraviolet region was observed, which makes the phosphor a potential candidate for ultraviolet light‐emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.
Enzymatic network for production of ether amines from alcohols
Authors: Palacio Cyntia M. , Crismaru Ciprian G. , Bartsch Sebastian , Navickas Vaidotas , Ditrich Klaus , Breuer Michael , Abu Rohana , Woodley John M. , Baldenius Kai , Wu Bian , Janssen Dick B.
Published: February 2016

We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the desired ether amines from the corresponding ether alcohols with inorganic ammonium as the only additional substrate. To examine conversion, individual and overall reaction equilibria were established. Using these data, it was found that the experimentally observed conversions of up to 60% observed for reactions containing 10 mM alcohol and up to 280 mM ammonia corresponded well to predicted conversions. The results indicate that efficient amination can be driven by high concentrations of ammonia and may require improving enzyme robustness for scale‐up. Biotechnol. Bioeng. 2016;113: 1853–1861. © 2016 Wiley Periodicals, Inc.
Fast plasmid based protein expression analysis in insect cells using an automated SplitGFP screen
Authors: Bleckmann Maren , Schmelz Stefan , Schinkowski Christian , Scrima Andrea , van den Heuvel Joop
Published: February 2016

Recombinant protein expression often presents a bottleneck for the production of proteins for use in many areas of animal‐cell biotechnology. Difficult‐to‐express proteins require the generation of numerous expression constructs, where popular prokaryotic screening systems often fail to identify expression of multi domain or full‐length protein constructs. Post‐translational modified mammalian proteins require an alternative host system such as insect cells using the Baculovirus Expression Vector System (BEVS). Unfortunately this is time‐, labor‐, and cost‐intensive. It is clearly desirable to find an automated and miniaturized fast multi‐sample screening method for protein expression in such systems. With this in mind, in this paper a high‐throughput initial expression screening method is described using an automated Microcultivation system in conjunction with fast plasmid based transient transfection in insect cells for the efficient generation of protein constructs. The applicability of the system is demonstrated for the difficult to express Nucleotide‐binding Oligomerization Domain‐containing protein 2 (NOD2). To enable detection of proper protein expression the rather weak plasmid based expression has been improved by a sensitive inline detection system. Here we present the functionality and application of the sensitive SplitGFP (split green fluorescent protein) detection system in insect cells. The successful expression of constructs is monitored by direct measurement of the fluorescence in the BioLector Microcultivation system. Additionally, we show that the results obtained with our plasmid‐based SplitGFP protein expression screen correlate directly to the level of soluble protein produced in BEVS. In conclusion our automated SplitGFP screen outlines a sensitive, fast and reliable method reducing the time and costs required for identifying the optimal expression construct prior to large scale protein production in baculovirus infected insect cells. Biotechnol. Bioeng. 2016;113: 1975–1983. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.
Concurrent microbial reduction of high concentrations of nitrate and perchlorate in an ion exchange membrane bioreactor
Authors: Fox Shalom , Bruner Tali , Oren Yoram , Gilron Jack , Ronen Zeev
Published: February 2016

We investigated effective simultaneous removal of high loads of nitrate and perchlorate from synthetic groundwater using an ion exchange membrane bioreactor (IEMB). The aim of this research was to characterize both transport aspects and biodegradation mechanisms involved in the treatment process of high loads of the two anions. Biodegradation process was proven to be efficient with over 99% efficiency of both perchlorate and nitrate, regardless of their load. The maximum biodegradation rates were 18.3 (mmol m−2 h−1) and 5.5 (mmol m−2 h−1) for nitrate and perchlorate, respectively. The presence of a biofilm on the bio‐side of the membrane only slightly increased the nitrate and perchlorate transmembrane flux as compared to the measured flux during a Donnan dialysis experiment where there is no biodegradation of perchlorate and nitrate in the bio‐compartment. The nitrate flux in presence of a biofilm was 18.3 (±1.9) (mmole m−2 h−1), while without the biofilm, the flux was 16.9 (±1.5) (mmole m−2 h−1) for the same feed inlet nitrate concentration of 4 mM. The perchlorate transmembrane flux increased similarly by an average of 5%. Samples of membrane biofilm and suspended bacteria from the bio‐reactor were analyzed for diversity and abundance of the perchlorate and nitrate reducing bacteria. Klebsiella oxytoca, known as a glycerol fermenter, accounted for 70% of the suspended bacteria. In contrast, perchlorate and nitrate reducing bacteria predominated in the biofilm present on the membrane. These results are consistent with our proposed two stage biodegradation mechanism where glycerol is first fermented in the suspended phase of the bio‐reactor and the fermentation products drive perchlorate and nitrate bio‐reduction in the biofilm attached to the membrane. These results suggest that the niche exclusion of microbial populations in between the reactor and membrane is controlled by the fluxes of the electron donors and acceptors. Such a mechanism has important implications for controlling the bio‐reduction reaction in the IEMB when using glycerol as a carbon source and allowing treating a complex contamination of high concentrations of perchlorate and nitrating in groundwater and successfully biodegrading them to non‐hazardous components. Biotechnol. Bioeng. 2016;113: 1881–1891. © 2016 Wiley Periodicals, Inc.
Transanal Endoscopic Operation under spinal anaesthesia
Authors: Arezzo A , Cortese G , Arolfo S , Bullano A , Passera R , Galietti E , Morino M
Published: February 2016

Background

Transanal Endoscopic Operation (TEO®) for rectal benign lesions and early rectal cancer may provide better oncological outcomes than flexible endoscopy. The major advantage of flexible endoscopy is that it does not require general anaesthesia. This prospective observational study assessed the feasibility and safety of TEO® performed under spinal anaesthesia.

Methods

The study population comprised eligible consecutive patients who underwent TEO® under spinal anaesthesia with curative or palliative intent for rectal neoplasms larger than 20 mm in diameter or for recurrent lesions of any size. The primary endpoints were feasibility and safety; secondary endpoints were postoperative pain, as measured on a visual analogue scale, heart rate, systolic and diastolic BP, opioid requested, postoperative nausea or vomiting, and urinary retention.

Results

The study included 50 patients (median age 70 years; 29 men and 21 women). No intraoperative complications occurred. The median duration of operation was 60 (range 20–165) min. No opioids were requested during the perioperative or postoperative period. The median postoperative pain score was 0 at 4, 8, 24 and 48 h after surgery. There were no significant fluctuations in heart rate, systolic and diastolic BP up to 48 h after the procedure (P = 0·379, P = 0·386 and P = 0·617 respectively). Postoperative nausea and vomiting occurred in one patient, and urinary retention in four.

Conclusion

TEO® under spinal anaesthesia was safe and feasible with no conversions to general anaesthesia.
Anatomic variation and orgasm: Could variations in anatomy explain differences in orgasmic success?
Authors: Emhardt E. , Siegel J. , Hoffman L.
Published: February 2016

Though the public consciousness is typically focused on factors such as psychology, penis size, and the presence of the “G‐spot,” there are other anatomical and neuro‐anatomic differences that could play an equal, or more important, role in the frequency and intensity of orgasms. Discovering these variations could direct further medical or procedural management to improve sexual satisfaction. The aim of this study is to review the available literature of anatomical sexual variation and to explain why this variation may predispose some patients toward a particular sexual experience. In this review, we explored the available literature on sexual anatomy and neuro‐anatomy. We used PubMed and OVID Medline for search terms, including orgasm, penile size variation, clitoral variation, Grafenberg spot, and benefits of orgasm. First we review the basic anatomy and innervation of the reproductive organs. Then we describe several anatomical variations that likely play a superior role to popular known variation (penis size, presence of g‐spot, etc). For males, the delicate play between the parasympathetic and sympathetic nervous systems is vital to achieve orgasm. For females, the autonomic component is more complex. The clitoris is the primary anatomical feature for female orgasm, including its migration toward the anterior vaginal wall. In conclusions, orgasms are complex phenomena involving psychological, physiological, and anatomic variation. While these variations predispose people to certain sexual function, future research should explore how to surgically or medically alter these. Clin. Anat. 29:665–672, 2016. © 2016 Wiley Periodicals, Inc.
History of cardiac anatomy: A comprehensive review from the egyptians to today
Authors: Loukas Marios , Youssef Pamela , Gielecki Jerzy , Walocha Jerzy , Natsis Kostantinos , Tubbs R. Shane
Published: February 2016

The nature, function, and anatomy of the heart have been extensively studied since 3500 B.C. Greek and Egyptian science developed a basic understanding of the heart, although this was primarily related to religious beliefs. During the Hippocratic era, Hippocrates and his colleagues developed a more scientific and less religious understanding of the cardiovascular system. The post‐Hippocratic era was characterized by more advanced descriptions of the location, structure, and function of the heart. The Alexandrian, Roman, Medieval Islamic, and European eras included turning points in the history of cardiac anatomy. Subsequently, after the structure and function of the heart were established, its connection with the lungs was investigated. Description of the pulmonary circulation was followed by the discovery of the conductive system and innervation of the heart. Clin. Anat. 29:270–284, 2016. © 2016 Wiley Periodicals, Inc.
Correlation between the Chemical and Genetic Relationships among Thymus saturejoides Genotypes Cultured under in vitro and in vivo Environments
Authors: Nordine Aicha , Udupa Sripada M. , Iraqi Driss , Meksem Khalid , Hmamouchi Mohamed , ElMeskaoui Abdelmalek
Published: February 2016

In this study, the in vitro and in vivo essential oil (EO) composition and genetic variability in six micropropagated genotypes of Thymus saturejoides Coss., a Mediterranean medicinal and aromatic plant, were analyzed by GC/MS and randomly amplified polymorphic DNA (RAPD). Yield and composition of the EO varied between genotypes. Cluster analysis based on RAPD data and EO grouped the six genotypes in three groups in both culture conditions, thus showing considerable intraspecific genetic and chemical variations. Applying the Mantel test, the result showed a significant correlation between the two proximity matrices RAPD and EO obtained from in vitro genotypes, whereas this correlation was not observed when using the EO obtained from the in vivo genotypes.
On the Permeation by Dioxygen of the Cofactor‐Independent Unusual Oxygenase RhCC, in Complex with Substrate 4‐Hydroxyphenylenolpyruvate. A Molecular Dynamics Investigation
Authors: Pietra Francesco
Published: February 2016

This work deals with a trimeric bacterial protein, RhCC, which, although belonging to the tautomerase superfamily, shows oxygenase activity. A model of the complex from RhCC and substrate 4‐hydroxyphenylenolpyruvate (4HPP), fitting the observation of extra electron densities from X‐ray diffraction of the crystal, could be built by autodocking. When subjected to molecular dynamics (MD) aided by an external random force applied to a O2 molecule placed above 4HPP, this model evolved with O2 egressing toward the bulk solvent from two nearly opposite gates. These were located between the nearly parallel helices 75 – 91 and 15 – 33 of either chain C (gate SE) or chain B (gate FL). Alternatively, with four O2 molecules in the bulk solvent, unbiased MD led to O2 entering the protein from gate SE and getting to 4HPP, while forming a stabilizing salt bridge between the 4HPP carboxylate and P1.C +NH2, thus providing scientific ground for a refined model of the complex.