bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterogeneous catalytic synthesis of poly(butylene succinate) by attapulgite‐supported Sn catalyst
Authors: Lai Shiquan , Gao Yan , Yue Li 
Published: December 2014

ABSTRACTAn attapulgite‐supported Sn catalyst (Sn‐palgorskite) was successfully prepared by ion‐exchange co‐impregnation method. The catalytic effect of Sn‐attapulgite on the melt polycondensation reaction of poly(butylene succinate) (PBS) was examined by comparing with that of anhydrous SnCl2 and a blank experiment. The structures and properties of the PBS products synthesized with the three catalytic systems were characterized by means of Fourier transform‐infrared spectra (FT‐IR), viscosity measurements, wide angle X‐ray diffraction (WARD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Meanwhile, the acidolysis degradation behaviors of the PBS samples were also studied. It was found that the intrinsic viscosities and the number‐average molecular weights of the PBS were remarkably increased under the catalysis of Sn‐attapulgite, further leading to an increase in the decomposition temperature, the crystallization temperature, and the viscous flow activation energy, while a decrease in the melting temperature, the relative degree of crystallinity, and the rate of degradation. Additionally, no significant differences were observed in the crystal structures of all the samples, regardless of the reaction system with or without catalyst. The experiment results confirmed that Sn‐attapulgite was an effective heterogeneous catalyst for the synthesis of PBS, and the recycled Sn‐attapulgite still exhibited higher activity than anhydrous SnCl2 under identical reaction conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41729.
Sialic Acid–Binding Immunoglobulin‐Type Lectin H–Positive Plasmacytoid Dendritic Cells Drive Spontaneous Lupus‐like Disease Development in B6.Nba2 Mice
Authors: Davison Laura M. , Jørgensen Trine N. 
Published: December 2014

ObjectivePatients with systemic lupus erythematosus (SLE) often present with elevated levels of interferon‐α (IFNα) in serum. Plasmacytoid dendritic cells (pDCs) have been suggested to be the primary source of IFNα in SLE due to their capacity to produce high levels of IFNα. During viral infection, a subset of pDCs expressing sialic acid–binding immunoglobulin‐type lectin H (Siglec H) produces the majority of pDC‐derived IFNα. The aim of this study was to provide evidence that Siglec H–positive pDCs are pathogenic in the IFNα‐dependent B6.Nba2 mouse model of lupus.MethodsB6.Nba2 blood dendritic cell antigen 2 (BDCA‐2)–diphtheria toxin receptor (DTR)–transgenic (Tg) mice were treated intraperitoneally with DT 3 times weekly starting at 4 weeks or 12 weeks of age and analyzed at 12 weeks and 18 weeks of age, respectively. Lupus‐like disease development was measured by the presence of elevated levels of autoantibodies in serum (as determined by enzyme‐linked immunosorbent assay), increased expression of IFN‐inducible genes (as determined by real‐time reverse transcription–polymerase chain reaction), increased IgG immune complex deposition in kidney glomeruli (as determined by immunofluorescence staining), spontaneous lymphocyte activation, and differentiation of B cells into antibody‐producing plasma cells (as determined by flow cytometry).ResultsB6.Nba2 mice in which Siglec H–positive pDCs were depleted for 6–8 weeks displayed reduced levels of IFNα‐induced gene transcripts and decreased anti‐chromatin autoantibody levels in serum, and significantly fewer activated splenic T cells and B cells, germinal center B cells, follicular helper T cells, and splenic plasma cells. In 18‐week‐old mice, IgG immune complex deposition in kidney glomeruli was similarly reduced.ConclusionThe development of lupus‐like disease in congenic B6.Nba2 mice depends on Siglec H–positive pDCs. We suggest that depletion of Siglec H–positive pDCs represents a novel cellular target in SLE.
Entwicklung eines neuartigen dynamischen Windsogprüfstandes für Bauteilprüfungen
Authors: Fouad Nabil A. , Richter Torsten , Vogel Tobias 
Published: December 2014

AbstractBauwerke können infolge Wind‐ und Böenbeanspruchungen enormen Belastungen ausgesetzt werden. Schadensfälle aus der Vergangenheit zeigten, dass selbst schwere Fassadenaufbauten beschädigt oder zum Herabstürzen gebracht werden können. Um von planerischer Seite die nötige Sicherheit zu schaffen, ist es daher sinnvoll, Fassaden‐ und Außenwandaufbauten vor ihrem Praxiseinsatz umfangreich auf ihre Windsogwiderstandsfähigkeit zu prüfen. Bisher dominieren hierzu Prüfverfahren, die Windlasten eher statisch simulieren können. Zur Prüfung von Konstruktionen auf realistische Böenbelastungen wurde am Institut für Bauphysik der Leibniz Universität Hannover ein dynamischer Windsogversuchsstand entwickelt und im Praxisverhalten getestet. Mit den zu erreichenden Unterdrücken von maximal 20 kPa ist der Versuchstand in der Lage, Windlasten an Prüfkörpern auch mit dynamischem Verhalten zu simulieren. Der Versuchsstand zeichnet sich hierbei durch eine hohe Wiederholgenauigkeit aus, die Messwerte werden lückenlos und mit einer hohen Abtastrate dokumentiert.Dynamic wind uplift test station at the “Institut für Bauphysik”, Leibniz University Hanover. From everyday experience it is known that structures induced by suction and gust loads may be exposed to enormous stress. Damages occurred in the past prove that heavy facade systems can be partly destroyed or even be forced to crashing down.To create the necessary safety it is appropriate to test the wind suction resistance of façade systems and external wall constructions before using them in practice. However, current test methods dominate which simulate wind loads rather static than dynamic. Therefore, the “Institut für Bauphysik” of the Leibniz University Hanover has developed a dynamical wind suction test station which is able to examine constructions regarding their dynamical wind suction resistance. Thereby testing the dynamic wind suction resistance means the abrupt and rapid applying of vacuum pressure on the tested construction, holding the vacuum pressure for a specific time and relieving the pressure on the specimen.
Knockdown of platinum‐induced growth differentiation factor 15 abrogates p27‐mediated tumor growth delay in the chemoresistant ovarian cancer model A2780cis
Authors: Meier Julia C. , Haendler Bernard , Seidel Henrik , Groth Philip , Adams Robert , Ziegelbauer Karl , Kreft Bertolt , Beckmann Georg , Sommer Anette , Kopitz Charlotte 
Published: December 2014

AbstractMolecular mechanisms underlying the development of resistance to platinum‐based treatment in patients with ovarian cancer remain poorly understood. This is mainly due to the lack of appropriate in vivo models allowing the identification of resistance‐related factors. In this study, we used human whole‐genome microarrays and linear model analysis to identify potential resistance‐related genes by comparing the expression profiles of the parental human ovarian cancer model A2780 and its platinum‐resistant variant A2780cis before and after carboplatin treatment in vivo. Growth differentiation factor 15 (GDF15) was identified as one of five potential resistance‐related genes in the A2780cis tumor model. Although A2780‐bearing mice showed a strong carboplatin‐induced increase of GDF15 plasma levels, the basal higher GDF15 plasma levels of A2780cis‐bearing mice showed no further increase after short‐term or long‐term carboplatin treatment. This correlated with a decreased DNA damage response, enhanced AKT survival signaling and abrogated cell cycle arrest in the carboplatin‐treated A2780cis tumors. Furthermore, knockdown of GDF15 in A2780cis cells did not alter cell proliferation but enhanced cell migration and colony size in vitro. Interestingly, in vivo knockdown of GDF15 in the A2780cis model led to a basal‐enhanced tumor growth, but increased sensitivity to carboplatin treatment as compared to the control‐transduced A2780cis tumors. This was associated with larger necrotic areas, a lobular tumor structure and increased p53 and p16 expression of the carboplatin‐treated shGDF15‐A2780cis tumors. Furthermore, shRNA‐mediated GDF15 knockdown abrogated p27 expression as compared to control‐transduced A2780cis tumors. In conclusion, these data show that GDF15 may contribute to carboplatin resistance by suppressing tumor growth through p27. These data show that GDF15 might serve as a novel treatment target in women with platinum‐resistant ovarian cancer.
Biogeographic Variation of Foliar n‐Alkanes of Juniperus communis var. saxatilisPallas from the Balkans
Authors: Rajčević Nemanja , Janaćković Pedja , Dodoš Tanja , Tešević Vele , Marin Petar D. 
Published: December 2014

AbstractThe composition of the epicuticular n‐alkanes isolated from the leaves of ten populations of Juniperus communis L. var. saxatilis Pallas from central (continental) and western (coastal) areas of the Balkan Peninsula was characterized by GC‐FID and GC/MS analyses. In the leaf waxes, 14 n‐alkane homologues with chain‐lengths ranging from C22 to C35 were identified. All samples were dominated by n‐tritriacontane (C33), but differences in two other dominant n‐alkanes allowed separating the coastal from the continental populations. Several statistical methods (ANOVA, principal component, discriminant, and cluster analyses as well as the Mantel test) were deployed to analyze the diversity and variability of the epicuticular‐leaf‐n‐alkane patterns of the ten natural populations of J. communis var. saxatilis and their relation to different geographic and bioclimatic parameters. Cluster analysis showed a high correlation of the leaf‐n‐alkane patterns with the geographical distribution of the investigated samples, differentiating the coastal from the continental populations of this taxon. Several bioclimatic parameters related to aridity were highly correlated with this differentiation.
Molecular Dynamics Simulation of Dioxygen Pathways through Mini Singlet Oxygen Generator (miniSOG), a Genetically Encoded Marker and Killer Protein
Authors: Pietra Francesco 
Published: December 2014

AbstractIn this work, molecular dynamics (MD) simulations of the permeation of proteins by small gases of biological significance have been extended from gas carrier, sensor, and enzymatic proteins to genetically encoded tags and killer proteins. To this end, miniSOG was taken as an example of current high interest, using a biased form of MD, called random‐acceleration MD. Various egress gates and binding pockets for dioxygen, as an indistinguishable mimic of singlet dioxygen, were found on both above and below the isoalloxazine plane of the flavin mononucleotide cofactor in miniSOG. Of such gates and binding pockets, those lying within two opposite cones, coaxial with a line normal to the isoalloxazine plane, and with the vertex at the center of such a plane are those most visited by the escaping gas molecule. Out of residues most capable of quenching 1O2, Y30, lying near the base of one such a cone, and H85, near the base of the opposite cone, are held to be most responsible for the reduced quantum yield of 1O2 with folded miniSOG with respect to free flavin mononucleotide in solution.
The Origin of Life: A Problem of History, Chemistry, and Evolution
Authors: Ma Wentao 
Published: December 2014

AbstractThe origin of life is a field full of controversies, not only because of our vague understanding concerning the relevant issues, but also, perhaps more often, owing to our dim conceptual framework throughout the whole field. To improve this situation, an in‐depth conceptual dissection is presented here. It is elucidated that, at its core, the origin of life has three aspects. The facts involved in the process are taken as the historical aspect, which is destined to be uncertain and often irrelevant to debate regarding details. The rules involved include two distinct aspects: chemical mechanisms operated in the whole process, while evolutionary mechanisms joined in only after the emergence of the first Darwinian entities – and then accounted for the subsequent buildup of complexity (this cannot be explained solely by natural selection). Basically, we can ask about the possibility of any assumed event in the origin of life: ‘Is it evolutionarily plausible, chemically feasible, and historically likely?’ Clues from any of the three aspects may be quite valuable in directing our explorations on the other two. This conceptual dissection provides a clearer context for the field, which may even be more useful than any sort of specific research.
Crystal Structure of HydG from Carboxydothermus hydrogenoformans: A Trifunctional [FeFe]‐Hydrogenase Maturase
Authors: Nicolet Yvain , Pagnier Adrien , Zeppieri Laura , Martin Lydie , Amara Patricia , Fontecilla‐Camps Juan C. 
Published: December 2014

AbstractThe structure of the radical S‐adenosyl‐L‐methionine (SAM) [FeFe]‐hydrogenase maturase HydG involved in CN−/CO synthesis is characterized by two internal tunnels connecting its tyrosine‐binding pocket with the external medium and the C‐terminal Fe4S4 cluster‐containing region. A comparison with a tryptophan‐bound NosL structure suggests that substrate binding causes the closing of the first tunnel and, along with mutagenesis studies, that tyrosine binds to HydG with its amino group well positioned for H‐abstraction by SAM. In this orientation the dehydroglycine (DHG) fragment caused by tyrosine CαCβ bond scission can readily migrate through the second tunnel towards the C‐terminal domain where both CN− and CO are synthesized. Our HydG structure appears to be in a relaxed state with its C‐terminal cluster CysX2CysX22Cys motif exposed to solvent. A rotation of this domain coupled to Fe4S4 cluster assembly would bury its putatively reactive unique Fe ion thereby allowing it to interact with DHG.
Total Syntheses and In Vivo Quantitation of Novel Neurofuran and Dihomo‐isofuran Derived from Docosahexaenoic Acid and Adrenic Acid
Authors: de la Torre Aurélien , Lee Yiu Yiu , Mazzoni Attilio , Guy Alexandre , Bultel‐Poncé Valérie , Durand Thierry , Oger Camille , Lee Jetty Chung‐Yung , Galano Jean‐Marie 
Published: December 2014

AbstractNeurofurans (NeuroFs) and dihomo‐isofurans (dihomo‐IsoFs) are produced in vivo by non‐enzymatic free‐radical pathways from docosahexaenoic and adrenic acids, respectively. As these metabolites are produced in minute amounts, their analyses in biological samples remain challenging. Syntheses of neurofuran and dihomo‐isofurans described are based on a pivotal strategy, thanks to an enantiomerically enriched intermediate, which allowed, for the first time, access to both families: the alkenyl and enediol. Owing to this formation, quantitation of specific NeuroF and dihomo‐IsoFs in biological samples was attainable.
Magnetically Recoverable Efficient Demulsifier for Water‐in‐Oil Emulsions
Authors: Chen Yuning , Lin Xin , Liu Na , Cao Yingze , Lu Fei , Xu Liangxin , Feng Lin 
Published: December 2014

AbstractA magnetically recoverable and efficient demulsifier is shown to demulsify surfactant‐stable water‐in‐oil emulsions rapidly. Ferroferric oxide (Fe3O4) particles are firstly coated by amorphous silicon dioxide (SiO2), and further functionalized with a commercial dodecyltrimethoxysilane solution (KH‐1231). Owing to their paramagnetic properties, the demulsifier particles can be easily recovered with a magnet. Upon addition of demulsifier to emulsions and subsequent sonification, the supernatant becomes completely transparent and no droplets are observed in the micrographs. It was also demonstrated that this demulsifier is effective for emulsions prepared with a variety of oils. Moreover, magnetically recovered demulsifier can be recycled after simple treatment without any decline of efficiency. This work presents a feasible approach for demulsifying water‐in‐oil emulsions, and has potential value in industry.
Electrifying White Biotechnology: Engineering and Economic Potential of Electricity‐Driven Bio‐Production
Authors: Harnisch Falk , Rosa Luis F. M. , Kracke Frauke , Virdis Bernardino , Krömer Jens O. 
Published: December 2014

AbstractThe production of fuels and chemicals by electricity‐driven bio‐production (i.e., using electric energy to drive biosynthesis) holds great promises. However, this electrification of white biotechnology is particularly challenging to achieve because of the different optimal operating conditions of electrochemical and biochemical reactions. In this article, we address the technical parameters and obstacles to be taken into account when engineering microbial bioelectrochemical systems (BES) for bio‐production. In addition, BES‐based bio‐production processes reported in the literature are compared against industrial needs showing that a still large gap has to be closed. Finally, the feasibility of BES bio‐production is analysed based on bulk electricity prices. Using the example of lysine production from sucrose, we demonstrate that there is a realistic market potential as cost savings of 8.4 % (in EU) and 18.0 % (in US) could be anticipated, if the necessary yields can be obtained.
Electrolytes Based on TEMPO–Co Tandem Redox Systems Outperform Single Redox Systems in Dye‐sensitized Solar Cells
Authors: Cong Jiayan , Hao Yan , Boschloo Gerrit , Kloo Lars 
Published: December 2014

AbstractA new TEMPO–Co tandem redox system with TEMPO and Co(bpy)32+/3+ has been investigated for the use in dye‐sensitized solar cells (DSSCs). A large open‐circuit voltage (VOC) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short‐circuit current density (JSC) was maintained. The conversion efficiency was observed to increase from 7.1 % for cells containing the single Co(bpy)32+/3+ redox couple, to 8.4 % for cells containing the TEMPO–Co tandem redox system. The reason for the increase in VOC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass‐transport of the metal‐complex‐based electrolyte is also improved. This TEMPO–Co tandem system is so far the most effienct tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.
Decoupling HZSM‐5 Catalyst Activity from Deactivation during Upgrading of Pyrolysis Oil Vapors
Authors: Wan Shaolong , Waters Christopher , Stevens Adam , Gumidyala Abhishek , Jentoft Rolf , Lobban Lance , Resasco Daniel , Mallinson Richard , Crossley Steven 
Published: December 2014

AbstractThe independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM‐5 catalysts in a separate fixed‐bed reactor controlled independently. Both the reactor‐bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis. Results show that there is an optimum catalyst‐bed temperature for the production of aromatics, above which the production of light gases increases and that of aromatics decrease. Zeolites with lower Si/Al ratios give comparable initial rates for aromatics production, but far more rapid catalyst deactivation rates than those with higher Si/Al ratios.
Emergence timing and fitness consequences of variation in seed oil composition in Arabidopsis thaliana
Authors: Pelc Sandra E. , Linder C. Randal 
Published: December 2014

AbstractEarly seedling emergence can increase plant fitness under competition. Seed oil composition (the types and relative amounts of fatty acids in the oils) may play an important role in determining emergence timing and early growth rate in oilseeds. Saturated fatty acids provide more energy per carbon atom than unsaturated fatty acids but have substantially higher melting points (when chain length is held constant). This characteristic forms the basis of an adaptive hypothesis that lower melting point seeds (lower proportion of saturated fatty acids) should be favored under colder germination temperatures due to earlier germination and faster growth before photosynthesis, while at warmer germination temperatures, seeds with a higher amount of energy (higher proportion of saturated fatty acids) should be favored. To assess the effects of seed oil melting point on timing of seedling emergence and fitness, high‐ and low‐melting point lines from a recombinant inbred cross of Arabidopsis thaliana were competed in a fully factorial experiment at warm and cold temperatures with two different density treatments. Emergence timing between these lines was not significantly different at either temperature, which aligned with warm temperature predictions, but not cold temperature predictions. Under all conditions, plants competing against high‐melting point lines had lower fitness relative to those against low‐melting point lines, which matched expectations for undifferentiated emergence times.
Native lipase dissolved in hydrophilic green solvents: A versatile 2‐phase reaction system for high yield ester synthesis
Authors: Kleiner Beatrice , Schörken Ulrich 
Published: December 2014

Native lipase B from Candida antarctica was evaluated for ester production in the presence of hydrophilic green solvents including DES. Ester yields of up to 98% were achieved without removing water from the system in single step transformations. Analysis of the lipid phase exhibited a low water content of 0.29 mg/mL in the presence of DES in contrast to 2.5 mg/mL without solvent. Thus, water adsorbing properties of the hydrophilic solvents are responsible for the equilibrium shift towards ester synthesis, which was even observed in the presence of more than 20% water in total. Non‐immobilized CalB was surprisingly active in hydrophilic solvents with logP‐values below −1, when 5–10% water was added to the solvent phase and initial reaction velocities were significantly higher than with other organic solvents. Optimum reaction conditions were in the range of 40–50 °C with a minimum content of 50 mg/kg pure CalB needed for full conversion. The solvent phase was easily separated by decantation and final product purification with established refinement procedures yielded esters of high quality. Stability testing of soluble lipase B revealed that enzyme stability in glycerol and ChCl:Gly is exceptionally high and stabilization of lipase in denaturing ChCl:U was possible in the presence of a lipid interface. The hydrophilic solvents were superior to less polar organic solvents in regards to ester yield and initial reaction velocity. A drawback of some hydrophilic solvents in lipase‐catalyzed reactions is byproduct formation due to their chemical structure containing hydroxyl groups.Practical applications: The proposed biocatalytic process is suited for the preparation of green esters for cosmetic and technical applications in “low‐cost” production equipment. As no water removal is needed to obtain high yields and no complex downstream processing is applied, the process may be conducted in simple stirred tank reactors. The recycling of the non‐volatile hydrophilic solvent by example decantation can easily be done in most production units. The utilization of soluble lipases in small quantities even allows for single‐use enzyme application, though the active enzyme may be recovered with the solvent and used again to minimize catalyst costs.Lipase CalB is dissolved in the hydrophilic phase consisting of a hydrogen bonding network of solvent and water molecules. Lipase catalysis takes place at the solvent/lipid interface and water is adsorbed into the solvent phase, thus shifting the equilibrium towards ester formation in the water‐depleted lipid phase.