bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Mechanism for Generating the Interferon Signature in Lupus: Opsonization of Dead Cells by Complement and IgM
Authors: Zhuang Haoyang , Han Shuhong , Li Yi , Kienhöfer Deborah , Lee Pui , Shumyak Stepan , Meyerholz Richard , Rosadzinski Krzysztof , Rosner Danielle , Chan Annie , Xu Yuan , Segal Mark , Sobel Eric , Yang Li‐Jun , Hoffmann Markus H. , Reeves Westley H.
Published: June 2016

Objective

In vitro studies suggest that the type I interferon (IFN) signature seen in most lupus patients results from Fcγ receptor–mediated uptake of nucleic acid–containing immune complexes by plasmacytoid dendritic cells and engagement of endosomal Toll‐like receptors. The aim of this study was to reexamine the pathogenesis of the IFN signature in vivo.

Methods

Lupus was induced in mice by injecting pristane. Some mice were treated with normal immunoglobulin or with cobra venom factor to deplete complement. The IFN signature was evaluated by polymerase chain reaction. The IFN signature also was determined in C4‐deficient patients and control subjects.

Results

Wild‐type C57BL/6 mice with pristane‐induced lupus developed a strong IFN signature, which was absent in immunoglobulin‐deficient (μMT), C3−/−, and CD18−/− mice. Intravenous infusion of normal IgM, but not IgG, restored the IFN signature in μMT mice, and the IFN signature in wild‐type mice was inhibited by depleting complement, suggesting that opsonization by IgM and complement is involved in IFN production. Consistent with that possibility, the levels of “natural” IgM antibodies reactive with dead cells were increased in pristane‐treated wild‐type mice compared with untreated controls, and in vivo phagocytosis of dead cells was impaired in C3‐deficient mice. To examine the clinical relevance of these findings, we identified 10 C4‐deficient patients with lupus‐like disease and compared them with 152 C4‐intact patients and 21 healthy controls. In comparison with C4‐intact patients, C4‐deficient patients had a different clinical/serologic phenotype and lacked the IFN signature.

Conclusion

These studies define previously unrecognized roles of natural IgM, complement, and complement receptors in generating the IFN signature in lupus.
Sulfur Confined in Sub‐Nanometer‐Sized 2 D Graphene Interlayers and Its Electrochemical Behavior in Lithium–Sulfur Batteries
Authors: Du Wen‐Cheng , Zhang Juan , Yin Ya‐Xia , Guo Yu‐Guo , Wan Li‐Jun
Published: June 2016

Microspace‐confined sulfur molecules as cathodes for lithium–sulfur (Li−S) batteries have shown great significance in both scientific and technical aspects. A study of different microspace‐confined sulfur will not only promote the advancement of Li−S batteries but also arouse a wide interest in sulfur chemistry and related applications. Herein, we choose two‐dimensional (2D) graphene interlayer as host and construct 2D space‐confined sulfur model systems by simple intercalation chemistry of graphite oxide. Two routes, including solvothermal method and interlamellar reaction approach, are developed, and sulfur can be easily intercalated into sub‐nanometer‐sized graphene interlayers, forming a graphene confined sulfur structure. The 2D space‐confined sulfur can work well in a carbonate‐based electrolyte and show similar electrochemical behaviors of small sulfur molecules, indicating the special molecular form of sulfur in graphene layers. The 2D space‐confined sulfur concept will be helpful for further understanding the electrochemical character of confined sulfur molecules and designing a high‐performance sulfur cathode.
Germline development in amniotes: A paradigm shift in primordial germ cell specification
Authors: Bertocchini Federica , Chuva de Sousa Lopes Susana M.
Published: June 2016

In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the ‘binary’ evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes.
Neuropeptide derivatives to regulate the reproductive axis: Kisspeptin receptor (KISS1R) ligands and neurokinin‐3 receptor (NK3R) ligands
Authors: Oishi Shinya , Fujii Nobutaka
Published: June 2016

Recent research has indicated pivotal roles for neuropeptides and their cognate receptors in reproductive physiology. Kisspeptins are RF‐amide neuropeptides that stimulate gonadotropin‐releasing hormone (GnRH) neurons in the hypothalamus. Neurokinin B (NKB) is a member of the tachykinin family of neuropeptides and positively regulates pulsatile GnRH secretion. These peptides are coexpressed in kisspeptin/NKB/Dyn (KNDy) neurons of the arcuate nucleus, where they contribute to the regulation of puberty onset and other reproductive functions. In this review, the design of peptide ligands for the kisspeptin (KISS1R) and neurokinin‐3 (NK3R) receptors are described. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 588–597, 2016.
Marital status and survival in patients with gastric cancer
Authors: Jin Jie‐Jie , Wang Wei , Dai Fa‐Xiang , Long Zi‐Wen , Cai Hong , Liu Xiao‐Wen , Zhou Ye , Huang Hua , Wang Ya‐Nong
Published: June 2016

The objective of this study is to examine the impact of marital status on incidence of metastasis at diagnosis, receipt of surgery, and cause‐specific survival (CSS) in patients with gastric cancer (GC). Research data is extracted from The Surveillance, Epidemiology, and End Results (SEER) database, and 18,196 patients diagnosed with GC from 2004 to 2010 are involved. Effects of marital status on incidence of metastasis at diagnosis, receipt of surgery, and CSS are determined using multivariable logistic regression and multivariable Cox regression models, as appropriate. Single GC patients have a higher incidence of metastasis at diagnosis than married patients, while the differences between divorced/separated patients or widowed patients and married patients are not significant. Among those without distant metastasis, single patients, divorced/separated patients, and widowed patients are much less likely to accept surgery compared with married patients. Finally, in the whole group of 18,196 GC patients, single patients, divorced/separated patients, and widowed patients have shorter CSS compared with married patients, even in each of the TNM stage. Marriage had a protective effect against undertreatment and cause‐specific mortality (CSM) in GC. Spousal support may contribute to higher rate of surgery receipt and better survival in patients with GC.
Effects of propolis and gamma‐cyclodextrin on intestinal neoplasia in normal weight and obese mice
Authors: Cho Youngjin , Gutierrez Linda , Bordonaro Michael , Russo Daniel , Anzelmi Frank , Hooven Jayde T. , Cerra Carmine , Lazarova Darina L.
Published: June 2016

Obesity is associated with colorectal cancer (CRC). This effect might be attributed to adipokine‐supported signaling. We have established that propolis suppresses survival signaling in CRC cells in vitro; therefore, we ascertained the ability of a propolis supplement to modulate intestinal neoplastic development in C57BL/6J‐ApcMin/+/J mice in the lean and obese state. To induce obesity, mice were fed with a Western diet containing 40% fat. Since the propolis supplement includes gamma‐cyclodextrin, the interventions included diets supplemented with or without gamma‐cyclodextrin. The animals were administered the following diets: (1) control diet, (2) control diet/gamma‐cyclodextrin, (3) control diet/propolis, (4) Western diet, (5) Western diet/gamma‐cyclodextrin, and (6) Western diet/propolis. Western diet, resulting in obesity, accelerated neoplastic progression, as evidenced by the larger size and higher grade dysplasia of the neoplasms. In the context of normal weight, gamma‐cyclodextrin and propolis affected neoplastic progression, as determined by the size of the lesions and their grade of dysplasia. A statistically significant decrease in the number of adenomas was detected in mice fed a control diet with the propolis supplement (61.8 ± 10.6 vs. 35.3 ± 7.6, P = 0.008). Although there was no significant difference in the polyp numbers between the six groups, the mice with the lowest number and size of adenomas were those fed a Western diet with gamma‐cyclodextrin. This unexpected outcome might be explained by the increased levels of apoptosis detected in the intestinal tissues of these obese mice. We posit that butyrate derived from the metabolism of gamma‐cyclodextrin may contribute to the decreased neoplastic burden in the context of obesity; however, future studies are required to address this possibility.
Monochorionic–diamniotic discordant growth in a twin pregnancy with one fetus affected by Ebstein's anomaly of tricuspid leaflets
Authors: Fukami Tatsuya , Goto Maki , Matsuoka Sakiko , Sorano Sumire , Tohyama Atsushi , Yamamoto Hiroko , Nakamura Sumie , Matsuoka Ryoei , Tsujioka Hiroshi , Eguchi Fuyuki
Published: June 2016

Key Clinical Message

Our patient was diagnosed as having discordant twin growth with Ebstein's anomaly in the larger fetus. Cardiac function was deteriorated in accordance with progression of gestational age. Our observation indicated cardiac failure of the larger fetus. The most important issue in this situation is management of the timing of delivery.
Semihydrogenation of Propyne over Cerium Oxide Nanorods, Nanocubes, and Nano‐Octahedra: Facet‐Dependent Parahydrogen‐Induced Polarization
Authors: Zhao Evan W. , Xin Yan , Hagelin‐Weaver Helena E. , Bowers Clifford R.
Published: June 2016

The pairwise selectivity of hydrogenation is a fundamental quantity in hydrogenation catalysis that underpins the NMR signal enhancement achievable by parahydrogen‐induced polarization (PHIP). Herein, we show how the crystal facet dependence of the pairwise selectivity of the semihydrogenation of propyne, when interpreted in the context of recent DFT calculations, can reveal new details about the hydrogenation mechanism. The pairwise selectivity of propyne hydrogenation is strongly shape dependent, which reflects the surface atom arrangements exposed on the different facets of CeO2 nanocrystals. In this first demonstration of a catalyst shape dependence of PHIP, an unprecedented pairwise selectivity of 8.1 % is observed over oxygen‐deficient facets of rods, whereas oxygen‐rich octahedra facets deliver only 1.6 % selectivity. The PHIP data are consistent with a concerted addition pathway through a six‐membered‐ring transition state, as predicted in the DFT study.
A Red to Near‐IR Fluorogen: Aggregation‐Induced Emission, Large Stokes Shift, High Solid Efficiency and Application in Cell‐Imaging
Authors: Wang Yi Jia , Shi Yang , Wang Zhaoyang , Zhu Zhenfeng , Zhao Xinyuan , Nie Han , Qian Jun , Qin Anjun , Sun Jing Zhi , Tang Ben Zhong
Published: June 2016

A tetraphenylethene (TPE) derivative modified with the strong electron acceptor 2‐dicyano‐methylene‐3‐cyano‐4,5,5‐trimethyl‐2,5‐dihydrofuran (TCF) was obtained in high yield by a simple two‐step reaction. The resultant TPE‐TCF showed evident aggregation‐induced emission (AIE) features and pronounced solvatochromic behavior. Changing the solvent from apolar cyclohexane to highly polar acetonitrile, the emission peak shifted from 560 to 680 nm (120 nm redshift). In an acetonitrile solution and in the solid powder, the Stokes shifts are as large as 230 and 190 nm, respectively. The solid film emits red to near‐IR (red‐NIR) fluorescence with an emission peak at 670 nm and a quantum efficiency of 24.8 %. Taking the advantages of red‐NIR emission and high efficiency, nanoparticles (NPs) of TPE‐TCF were fabricated by using tat‐modified 1,2‐distearoylsn‐glycero‐3‐phosphor‐ethanol‐amine‐N‐[methoxy‐(polyethyl‐eneglycol)‐2000] as the encapsulation matrix. The obtained NPs showed perfect membrane penetrability and high fluorescent imaging quality of cell cytoplasm. Upon co‐incubation with 4,6‐diamidino‐2‐phenylindole (DAPI) in the presence of tritons, the capsulated TPE‐TCF nanoparticles could enter into the nucleus and displayed similar staining properties to those of DAPI.
Synthesis of a Pentacene‐Type Silaborin via Double Dehydrogenative Cyclization of 1,4‐Diboryl‐2,5‐disilylbenzene
Authors: Hirofuji Tatsuya , Ikeda Toshiaki , Haino Takeharu , Yamamoto Yohsuke , Kawachi Atsushi
Published: June 2016

A new pentacene‐type silaborin, in which three benzene rings are bridged by silicon and boron atoms, has been synthesized and characterized by using NMR spectroscopy and X‐ray crystallographic analysis. The precursor, 1,4‐bis(dimesitylboryl)‐2,5‐bis(phenylsilyl)benzene (4), was prepared by stepwise introduction of a silyl group and a boryl group to a benzene ring starting from 1,4‐dibromobenzene. Double cyclization of 4 proceeds by a H‐Mes exchange and a B‐H/C‐H dehydrogenative condensation to afford pentacene‐type silaborin 5. X‐ray crystal structure analysis reveals that 5 adopts a bent structure rather than a planar one. UV/Vis spectra and DFT calculations for 5 reveal a lowering of the LUMO energy level compared with corresponding anthracene‐type 3.
High‐Performance of Gas Hydrates in Confined Nanospace for Reversible CH4/CO2 Storage
Authors: Casco Mirian E. , Jordá José L. , Rey Fernando , Fauth François , Martinez‐Escandell Manuel , Rodríguez‐Reinoso Francisco , Ramos‐Fernández Enrique V. , Silvestre‐Albero Joaquín
Published: June 2016

The molecular exchange of CH4 for CO2 in gas hydrates grown in confined nanospace has been evaluated for the first time using activated carbons as a host structure. The nano‐confinement effects taking place inside the carbon cavities and the exceptional physicochemical properties of the carbon structure allows us to accelerate the formation and decomposition process of the gas hydrates from the conventional timescale of hours/days in artificial bulk systems to minutes in confined nanospace. The CH4/CO2 exchange process is fully reversible with high efficiency at practical temperature and pressure conditions. Furthermore, these activated carbons can be envisaged as promising materials for long‐distance natural gas and CO2 transportation because of the combination of a high storage capacity, a high reversibility, and most important, with extremely fast kinetics for gas hydrate formation and release.
Redox‐Active Tetraruthenium Macrocycles Built from 1,4‐Divinylphenylene‐Bridged Diruthenium Complexes
Authors: Scheerer Stefan , Linseis Michael , Wuttke Evelyn , Weickert Sabrina , Drescher Malte , Tröppner Oliver , Ivanović‐Burmazović Ivana , Irmler Andreas , Pauly Fabian , Winter Rainer F.
Published: June 2016

Metallamacrocylic tetraruthenium complexes were generated by treatment of 1,4‐divinylphenylene‐bridged diruthenium complexes with functionalized 1,3‐benzene dicarboxylic acids and characterized by HR ESI‐MS and multinuclear NMR spectroscopy. Every divinylphenylene diruthenium subunit is oxidized in two consecutive one‐electron steps with half‐wave potential splittings in the range of 250 to 330 mV. Additional, smaller redox‐splittings between the +/2+ and 0/+ and the 3+/4+ and 2+/3+ redox processes, corresponding to the first and the second oxidations of every divinylphenylene diruthenium entity, are due to electrostatic effects. The lack of electronic coupling through bond or through space is explained by the nodal properties of the relevant molecular orbitals and the lateral side‐by‐side arrangement of the divinylphenylene linkers. The polyelectrochromic behavior of the divinylphenylene diruthenium precursors is retained and even amplified in these metallamacrocyclic structures. EPR studies down to T=4 K indicate that the dications 1‐H2+ and 1‐OBu2+ are paramagnetic. The dications and the tetracation of macrocycle 3‐H display intense (dications) or weak (3‐H4+) EPR signals. Quantum chemical calculations indicate that the four most stable conformers of the macrocycles are largely devoid of strain. Bond parameters, energies as well as charge and spin density distributions of model macrocycle 5‐HMe were calculated for the different charge and spin states.
Toward Fluorescence‐Based High‐Throughput Screening for Enantiomeric Excess in Amines and Amino Acid Derivatives
Authors: Shcherbakova Elena G. , Brega Valentina , Minami Tsuyoshi , Sheykhi Sara , James Tony D. , Anzenbacher Pavel
Published: June 2016

A highly accurate and reliable screening method for enantiomeric excess of amine derivatives in the presence of water is reported. The fluorescence‐based screening system has been realized by self‐assembly of chiral diol‐type dyes (BINOL, VANOL and VAPOL), 2‐formylphenylboronic acid, and chiral amines forming iminoboronate esters. The structure and chirality of the amine analytes determine the stability of the diastereomeric iminoboronate esters, which in turn display differential fluorescence. The fluorescence signal reflects the enantiomeric purity of the chiral amines and was utilized in high‐throughput arrays. The arrays were able to recognize enantiomeric excess of amines, amino esters, and amino alcohols. In addition to qualitative analysis, quantitative experiments were successfully performed. Studies of the role of additives such as water or citrate were carried out to gain insight into the stability of the iminoboronate esters. It is shown that the above additives destabilize less stable esters while the stable esters remain unchanged. Thus, the presence of water and citrate leads to increased difference between the diastereomeric iminoboronates and contributes to the enantiodiscrimination of the chiral amines.
Isolation and Ambident Reactivity of a Chlorogermylenoid
Authors: Suzuki Yuko , Sasamori Takahiro , Guo Jing‐Dong , Nagase Shigeru , Tokitoh Norihiro
Published: June 2016

Treatment of 2,5‐di(3,5‐tert‐butylphenyl)‐1‐lithioferrocene with GeCl2⋅dioxane afforded the corresponding chlorogermylenoid that exhibited an ambident reactivity in different solvents; it displayed a behavior characteristic for a dichlorogermylene anion in THF, while it exhibited the typical reactivity of a chlorogermylene in toluene. X‐Ray diffraction analysis of a single crystal of this chlorogermylenoid, obtained from recrystallization in THF, revealed a separated‐ion‐pair structure in the solid state.
A meta‐analysis of the UTAUT model: Eleven years later
Authors: Khechine Hager , Lakhal Sawsen , Ndjambou Paterne
Published: June 2016

The unified theory of acceptance and use of technology (UTAUT) has been widely used to investigate factors influencing the adoption and use of information systems and technologies (IS/IT). However, studies using UTAUT are not conclusive in terms of statistical significance, direction, and magnitude. Through a meta‐analysis of empirical studies on UTAUT from 2003 to 2013, we determine how parsimonious, accurate, and robust UTAUT is at predicting acceptance and use of technology. A meta‐analysis of 74 publications reveals that performance expectancy, effort expectancy, and social influence explain IS/IT adoption, while behavioural intention is the most often measured dependent variable operationalized as a proxy for system use, supporting the strength of UTAUT as an explanatory model of IS/IT acceptance and use. Copyright © 2016 ASAC. Published by John Wiley & Sons, Ltd.
Rapid and reliable diagnosis of Wilson disease using X‐ray fluorescence
Authors: Kaščáková Slávka , Kewish Cameron M. , Rouzière Stéphan , Schmitt Françoise , Sobesky Rodolphe , Poupon Joël , Sandt Christophe , Francou Bruno , Somogyi Andrea , Samuel Didier , Jacquemin Emmanuel , Dubart‐Kupperschmitt Anne , Nguyen Tuan Huy , Bazin Dominique , Duclos‐Vallée Jean‐Charles , Guettier Catherine , Le Naour François
Published: June 2016

Wilson's disease (WD) is a rare autosomal recessive disease due to mutations of the gene encoding the copper‐transporter ATP7B. The diagnosis is hampered by the variability of symptoms induced by copper accumulation, the inconstancy of the pathognomonic signs and the absence of a reliable diagnostic test. We investigated the diagnostic potential of X‐ray fluorescence (XRF) that allows quantitative analysis of multiple elements. Studies were performed on animal models using Wistar rats (n = 10) and Long Evans Cinnamon (LEC) rats (n = 11), and on human samples including normal livers (n = 10), alcohol cirrhosis (n = 8), haemochromatosis (n = 10), cholestasis (n = 6) and WD (n = 22). XRF experiments were first performed using synchrotron radiation to address the elemental composition at the cellular level. High‐resolution mapping of tissue sections allowed measurement of the intensity and the distribution of copper, iron and zinc while preserving the morphology. Investigations were further conducted using a laboratory X‐ray source for irradiating whole pieces of tissue. The sensitivity of XRF was highlighted by the discrimination of LEC rats from wild type even under a regimen using copper deficient food. XRF on whole formalin‐fixed paraffin embedded needle biopsies allowed profiling of the elements in a few minutes. The intensity of copper related to iron and zinc significantly discriminated WD from other genetic or chronic liver diseases with 97.6% specificity and 100% sensitivity. This study established a definite diagnosis of Wilson's disease based on XRF. This rapid and versatile method can be easily implemented in a clinical setting.
Dynamics of Molecular Crystals by Means of 1H NMR Relaxometry: Dynamical Heterogeneity versus Homogenous Motion
Authors: Kruk Danuta , Florek‐Wojciechowska Małgorzata , Jakubas Ryszard , Chaurasia Sujeet K. , Brym Szczepan
Published: June 2016

1H NMR relaxometry was used to reveal information on the dynamical properties of the molecular crystal (PyH)5Bi2Br11 (PyH=C5H6N, pyridinium cation), chosen as an example of a solid that exhibits a complex structure and rotational‐like dynamics. Experimental studies were performed over a very broad frequency range, from 4 kHz to 40 MHz (referring to the 1H resonance frequency) versus temperature. The extensive set of data was thoroughly analyzed in terms of two motional models differing with respect to the assumed mechanism (heterogeneous versus homogenous) of the motion of the PyH cations. A Cole–Davidson distribution of the correlation times describing the assumed motional heterogeneity was tested against a concept of two correlation times characterizing the rotation‐like dynamics of the PyH cation around the perpendicular axes differing by about one order of magnitude. The parameters describing the dynamics of the cation, obtained by means of both models, were compared and discussed.
DFT‐Based Simulation and Experimental Validation of the Topotactic Transformation of MgAl Layered Double Hydroxides
Authors: Zhang Shi‐Tong , Dou Yibo , Zhou Junyao , Pu Min , Yan Hong , Wei Min , Evans David G. , Duan Xue
Published: June 2016

The thermal topotactic transformation mechanism of MgAl layered double hydroxides (LDHs) is investigated by a combined theoretical and experimental study. Thermogravimetric differential thermal analysis (TG‐DTA) results reveal that the LDH phase undergoes four key endothermic events at 230, 330, 450, and 800 °C. DFT calculations show that the LDH decomposes into CO2 and residual O atoms via a monodentate intermediate at 330 °C. At 450 °C, the metal cations almost maintain their original distribution within the LDH(001) facet during the thermal dehydration process, but migrate substantially along the c‐axis direction perpendicular to the (001) facet; this indicates that the metal arrangement/dispersion in the LDH matrix is maintained two‐dimensionally. A complete collapse of the layered structure occurs at 800 °C, which results in a totally disordered cation distribution and many holes in the final product. The structures of the simulated intermediates are highly consistent with the observed in situ powder XRD data for the MgAl LDH sample calcined at the corresponding temperatures. Understanding the structural topotactic transformation process of LDHs would provide helpful information for the design and preparation of metal/metal oxides functional materials derived from LDH precursors.
Ordered Mesoporous Polyoxometalate–Organosilica Frameworks as Efficient Photocatalysts of the Hydrogen Evolution Reaction
Authors: Koutsouroubi Eirini D. , Papadas Ioannis T. , Armatas Gerasimos S.
Published: June 2016

Polyoxometalate clusters have been recently established as promising nanomaterials for photocatalytic water splitting. Here, the synthesis is reported of mesoporous polymers composed of a 3D porous network of lacunary [XM11O39]q− (XM11; X=P, Si; M=W, Mo) polyoxometalate units connected by ethano‐bridged silsesquioxane linkers through a block copolymer‐templated crosslinking polymerization of 1,2‐bis(triethoxysilyl)ethane in acidic solution. The resulting materials feature an ordered mesostructured ethane–silica (MES) framework that hosts a high density of accessible polyoxometalate clusters, which allows for efficient catalytic reactions. XM11/MES hybrid polymers have a relatively high activity for the hydrogen evolution reaction with remarkable cycle stability under UV/Vis light irradiation (λ>360 nm), without the need for co‐catalysts or additional photosensitizers. It is also shown that the photocatalytic efficiency of these materials arises from the nanoscale pore structure, high surface area and chemical manipulation of the electronic band structure of constituting heteropolyoxo clusters.
Artificial Hydrogenases Based on Cobaloximes and Heme Oxygenase
Authors: Bacchi Marine , Veinberg Elias , Field Martin J. , Niklas Jens , Matsui Toshitaka , Tiede D. M. , Poluektov Oleg G. , Ikeda‐Saito Masao , Fontecave Marc , Artero Vincent
Published: June 2016

The insertion of cobaloxime catalysts in the heme‐binding pocket of heme oxygenase (HO) yields artificial hydrogenases active for H2 evolution in neutral aqueous solutions. These novel biohybrids have been purified and characterized by using UV/visible and EPR spectroscopy. These analyses revealed the presence of two distinct binding conformations, thereby providing the cobaloxime with hydrophobic and hydrophilic environments, respectively. Quantum chemical/molecular mechanical docking calculations found open and closed conformations of the binding pocket owing to mobile amino acid residues. HO‐based biohybrids incorporating a {Co(dmgH)2} (dmgH2=dimethylglyoxime) catalytic center displayed up to threefold increased turnover numbers with respect to the cobaloxime alone or to analogous sperm whale myoglobin adducts. This study thus provides a strong basis for further improvement of such biohybrids, using well‐designed modifications of the second and outer coordination spheres, through site‐directed mutagenesis of the host protein.
Quantification methods for human and large animal leukocytes using DNA dyes by flow cytometry
Authors: Pieper Ina Laura , Radley Gemma , Chan Chris H. H. , Friedmann Yasmin , Foster Graham , Thornton Catherine A.
Published: June 2016

Ovine and bovine blood is used heavily within the development of blood‐handling medical devices, such as heart pumps (left ventricular assist devices, LVADs), for which blood cell damage needs to be monitored during in vitro testing. Hematology analyzers provide cell counts but no information about cell viability. The anthraquinone DNA dyes CyTRAK Orange™ and DRAQ7™ have practical and spectral properties rendering them suitable for multicolor assays. Compared to other DNA dyes such as Vybrant Dyecycle, CyTRAK Orange enables a faster staining protocol and does not require incubation at +37°C. Compared to traditional viability dyes such as propidium iodide and 7AAD, DRAQ7's unique spectral profile of excitation in both blue and red lasers and far‐red emission enables identification of dual positive dead cell events and frees up detectors for use with other reagents. CyTRAK Orange and DRAQ7 could be used in combination with absolute counting bead standards to provide cell counts and viability but the combination of these dyes has previously only been used for microscopy on rodent cells. The purpose of this study was to evaluate the use of these dyes in combination in large animal blood samples for flow cytometry. A viability and cell counting protocol for bovine, ovine, and human leukocytes using CyTRAK Orange and DRAQ7 was prepared. Four different counting bead standards were evaluated using the Navios and FACSAria cytometers and compared to counts obtained from hematology analyzers. CyTRAK Orange successfully detected CD45+leukocytes in all species. The DRAQ7 single‐stained dead cell counts correlated well with the CyTRAK Orange/DRAQ7 double‐stained dead cell counts in human and bovine blood, but not in ovine blood, which could be related to the blood source. In conclusion, for human and bovine blood, this method works well for viability counts using different flow cytometers and bead standards. © 2016 International Society for Advancement of Cytometry
Application of image cytometry to characterize heterologous lipid flippases in yeast
Authors: Jensen Maria S. , Costa Sara R. , Theorin Lisa , Christensen Jan Pravsgaard , Pomorski Thomas Günther , López‐Marqués Rosa L.
Published: June 2016

Lipid flippases are integral membrane proteins that play a central role in moving lipids across cellular membranes. Some of these transporters are ATPases that couple lipid translocation to ATP hydrolysis, whereas others function without any discernible metabolic energy input. A growing number of lipid flippases has been identified but key features of their activity remain to be elucidated. A well‐established method to characterize ATP‐driven flippases is based on their heterologous expression in yeast, followed by incubation of the cells with fluorescent lipids. Internalization of these probes is typically monitored by flow cytometry, a costly and maintenance‐intensive method. Here, we have optimized a protocol to use an automated image‐based cell counter to accurately measure lipid uptake by heterologous lipid flippases expressed in yeast. The method was validated by comparison with the classical flow cytometric evaluation of lipid‐labeled cells. In addition, we demonstrated that expression of fluorescently tagged flippase complexes can be directly co‐related with fluorescent lipid uptake using the image‐based cell counter system. The method extends the number of techniques available for characterization of lipid flippase activity, and should be readily adaptable to analyze a variety of other transport systems in yeast, parasites, and mammalian cells. © 2016 International Society for Advancement of Cytometry
Masonry buildings at the borderline to high‐rise – Part 2 / Mauerwerksbauten an der Hochhausgrenze – Teil 2
Authors: Seim Werner , Sommerlade Kai
Published: June 2016

For the verification of framing shear walls of masonry, the decisive combination of actions derives from the interaction of vertical and horizontal actions. In this article, a method based on simple truss models is extended for the transfer of horizontal actions. It is demonstrated how the required verifications of load‐bearing safety can be performed with the results of the structural calculation. As an example, the application of the method for a seven‐storey building with calcium silicate blockwork or Poroton brick masonry is described.
Analysis of steel‐reinforced masonry walls regarding maximum shear loads / Traglastberechnung von vertikal bewehrten Mauerwerksscheiben
Authors: Stempfle Hartwig , Weber Marius , Wipfli Manuel
Published: June 2016

Loadings on masonry for the earthquake case pose particular challenges for the material. In order to improve the load‐bearing and deformation behaviour, masonry building elements can be strengthened with reinforcement. This article presents an analytical model for the calculation of the load‐bearing capacity of vertically reinforced masonry panels. The masonry is modelled as a homogeneous and anisotropic material and failure conditions are based on the plastic theory. Using uniaxially loaded stress fields and considering the structural constraints, a lower load‐bearing threshold can be given. In order to verify the model, three shear tests on reinforced sand‐lime block masonry were recalculated regarding their load‐bearing capacity. The test panels each contained vertical steel reinforcement in the blocks. The blocks were laid in thin bed mortar.
Return of the lysergamides. Part II: Analytical and behavioural characterization of N6‐allyl‐6‐norlysergic acid diethylamide (AL‐LAD) and (2’S,4’S)‐lysergic acid 2,4‐dimethylazetidide (LSZ)
Authors: Brandt Simon D. , Kavanagh Pierce V. , Westphal Folker , Elliott Simon P. , Wallach Jason , Colestock Tristan , Burrow Timothy E. , Chapman Stephen J. , Stratford Alexander , Nichols David E. , Halberstadt Adam L.
Published: June 2016

Lysergic acid N,N‐diethylamide (LSD) is perhaps one of the most intriguing psychoactive substances known and numerous analogs have been explored to varying extents in previous decades. In 2013, N6‐allyl‐6‐norlysergic acid diethylamide (AL‐LAD) and (2’S,4’S)‐lysergic acid 2,4‐dimethylazetidide (LSZ) appeared on the ‘research chemicals’/new psychoactive substances (NPS) market in both powdered and blotter form. This study reports the analytical characterization of powdered AL‐LAD and LSZ tartrate samples and their semi‐quantitative determination on blotter paper. Included in this study was the use of nuclear magnetic resonance (NMR) spectroscopy, gas chromatography‐mass spectrometry (GC‐MS), low and high mass accuracy electrospray MS(/MS), high performance liquid chromatography diode array detection and GC solid‐state infrared analysis. One feature shared by serotonergic psychedelics, such as LSD, is the ability to mediate behavioural responses via activation of 5‐HT2A receptors. Both AL‐LAD and LSZ displayed LSD‐like responses in male C57BL/6 J mice when employing the head‐twitch response (HTR) assay. AL‐LAD and LSZ produced nearly identical inverted‐U‐shaped dose‐dependent effects, with the maximal responses occurring at 200 µg/kg. Analysis of the dose responses by nonlinear regression confirmed that LSZ (ED50 = 114.2 nmol/kg) was equipotent to LSD (ED50 = 132.8 nmol/kg) in mice, whereas AL‐LAD was slightly less potent (ED50 = 174.9 nmol/kg). The extent to which a comparison in potency can be translated directly to humans requires further investigation. Chemical and pharmacological data obtained from NPS may assist research communities that are interested in various aspects related to substance use and forensic identification. Copyright © 2016 John Wiley & Sons, Ltd.
Long‐term impacts of dam construction on plant succession and survival of an endangered species
Authors: Lucas S. D. , Wheeler J. A. , Atallah Y. C. , Walker S. E. , Jones C. E. , Burk J. H.
Published: June 2016

This study was conducted to determine what changes have occurred in an arid alluvial riparian shrub habitat in the upper Santa Ana River basin over a 20+‐yr period beginning prior to the completion of the Seven Oaks Dam in San Bernardino County, California and continuing until 8 yr after the completion of the dam in 2000 to assess the implications any changes may have on the persistence of the short‐lived Santa Ana River Woolly Star (Eriastrum densifolium ssp. sanctorum, Polemoniaceae). Small‐scale habitat changes were determined by comparing non‐native annual plant data from 1989 to 2008. Large‐scale habitat changes were determined by comparing perennial plant data from 1987 to 2008. The results of this study suggest that annual species, lichen crust, and dead shrubs are increasing, and that bare ground and live shrubs are decreasing. The older sites are also increasing in annual grass cover. Successional changes have occurred since the last significant flood event in 1969 although these changes are gradual and on a continuum, precluding a sharp distinction between different age stages. The data support previously predicted rates of succession indicating ultimate maturity within at least 100 yr. The continuation of these habitat changes will likely contribute to the decline of the Woolly Star population, particularly during future drought periods.
A spatially‐explicit assessment of the fish population response to flow management in a heterogeneous landscape
Authors: Guénard Guillaume , Lanthier Gabriel , Harvey‐Lavoie Simonne , Macnaughton Camille J. , Senay Caroline , Lapointe Michel , Legendre Pierre , Boisclair Daniel
Published: June 2016

Ecological processes are structured in space and there are important benefits in incorporating spatial information for the analysis of data sets obtained from field studies. Assessing the effect of different flow management practices on river ecosystems is an example where such an exercise is highly relevant. Human activities such as hydroelectric power production are known to modify the temporal variability in river flow. Flow management strategies may have a direct influence on fishes and may trigger complex cascades of interactions involving different features of the river ecosystem. In this study, we performed an assessment of the effect of different flow management practices on fish count density (no. fish/m2), biomass density (g/m2), and species richness. Data were collected in 941 sites located along 28 Canadian rivers. These rivers were either naturally flowing or had altered flows from one of three flow management strategies: run of the river dams, storage with gradual release, or storage with peak release. Each site (300 m2) was surveyed using paired snorkeling and electrofishing techniques; environmental variables (water depth and velocity, and substrate composition) were also measured. The study spanned a broad geographic range (3497 km, geodesic distance) and involved repeated local observations (16–50 sites/river), and was therefore inherently spatially organized. We used spatial modeling to obtain a baseline to estimate the effect of flow management strategies on fishes. Our results indicate that rivers downstream of flow peaking storage dams have, by far, the lowest fish densities (count and biomass) and species richness, whereas those downstream of gradual release storage dams had higher fish biomass density than the unregulated rivers.
To cross or not to cross: modeling wildlife road crossings as a binary response variable with contextual predictors
Authors: Siers Shane R. , Reed Robert N. , Savidge Julie A.
Published: June 2016

Roads are significant barriers to landscape‐scale movements of individuals or populations of many wildlife taxa. The decision by an animal near a road to either cross or not cross may be influenced by characteristics of the road, environmental conditions, traits of the individual animal, and other aspects of the context within which the decision is made. We considered such factors in a mixed‐effects logistic regression model describing the nightly road crossing probabilities of invasive nocturnal Brown Treesnakes (Boiga irregularis) through short‐term radiotracking of 691 snakes within close proximity to 50 road segments across the island of Guam. All measures of road magnitude (traffic volume, gap width, surface type, etc.) were significantly negatively correlated with crossing probabilities. Snake body size was the only intrinsic factor associated with crossing rates, with larger snakes crossing roads more frequently. Humidity was the only environmental variable affecting crossing rate. The distance of the snake from the road at the start of nightly movement trials was the most significant predictor of crossings. The presence of snake traps with live mouse lures during a portion of the trials indicated that localized prey cues reduced the probability of a snake crossing the road away from the traps, suggesting that a snake's decision to cross roads is influenced by local foraging opportunities. Per capita road crossing rates of Brown Treesnakes were very low, and comparisons to historical records suggest that crossing rates have declined in the 60+ yr since introduction to Guam. We report a simplified model that will allow managers to predict road crossing rates based on snake, road, and contextual characteristics. Road crossing simulations based on actual snake size distributions demonstrate that populations with size distributions skewed toward larger snakes will result in a higher number of road crossings. Our method of modeling per capita road crossing probabilities as a binary response variable, influenced by contextual factors, may be useful for describing or predicting road crossings by individuals of other taxa provided that appropriate spatial and temporal resolution can be achieved and that potentially influential covariate data can be obtained.
Social information use by competitors: Resolving the enigma of species coexistence in animals?
Authors: Parejo Deseada , Avilés Jesús M.
Published: June 2016

The competitive exclusion principle states that species limited by the same factors cannot share the same environment. Challenging this paradigm, empirical studies often report competitors' coexistence in natural communities, which has long puzzled evolutionary ecologists. Theoretical studies on animal communities have conferred a prime role to the negative effects of interactions in explaining coexistence, but largely neglected the potential positive side of interactions. Here, we propose that living close to a competitor could have beneficial aspects because competitors may provide fitness‐enhancing social information, which under some circumstances may counter the negative effects of competition, thus promoting coexistence. We use conceptual models and discuss factors influencing social information use and their influence on the outcome of competitors' interaction in terms of coexistence probability. Finally, we discuss ecological and evolutionary implications of these processes and suggest exciting avenues for future research on animal communities.
Differential impacts from an extreme cold spell on subtropical vs. tropical specialist bees in southern Florida
Authors: Downing Jason , Borrero Haydee , Liu Hong
Published: June 2016

Gradual warming and changes in extreme weather patterns associated with human induced climate change are altering the range distributions of species. However, species responses to climate change are predicted to be more strongly affected by extreme events than by changes in mean values. As a result, measuring species' responses to extreme events in addition to the mean changes in climate are necessary to predict species range limits under future conditions. This study examines the impacts of a cold spell in southern Florida on native and an introduced oil‐collecting bees by examining the bees' interactions with two native plants species. Our results provide evidence of differential impacts from an extreme cold event on a native, subtropical bee vs. an introduced, tropical bee. Specifically, the cold spell had little impact on the abundance of the native bee, while the abundance of the introduced, tropical bee was negatively impacted. Our findings demonstrate that extreme cold spells are important climate change‐related phenomena that can have strong impacts on tropical species distributions and abundances, especially at the threshold of their thermal tolerances. Our approach also provided a rare opportunity to examine these impacts on multiple interacting species, which provides a more realistic assessment of the potential impacts of climate change.
Vegetation productivity responds to sub‐annual climate conditions across semiarid biomes
Authors: Barnes Mallory L. , Moran M. Susan , Scott Russell L. , Kolb Thomas E. , Ponce‐Campos Guillermo E. , Moore David J. P. , Ross Morgan A. , Mitra Bhaskar , Dore Sabina
Published: June 2016

In the southwest United States, the current prolonged warm drought is similar to the predicted future climate change scenarios for the region. This study aimed to determine patterns in vegetation response to the early 21st century drought across multiple biomes. We hypothesized that different biomes (forests, shrublands, and grasslands) would have different relative sensitivities to both climate drivers (precipitation and temperature) and legacy effects (previous‐year's productivity). We tested this hypothesis at eight Ameriflux sites in various Southwest biomes using NASA Moderate‐resolution Imaging Spectroradiometer Enhanced Vegetation Index (EVI) from 2001 to 2013. All sites experienced prolonged dry conditions during the study period. The impact of combined precipitation and temperature on Southwest ecosystems at both annual and sub‐annual timescales was tested using Standardized Precipitation Evapotranspiration Index (SPEI). All biomes studied had critical sub‐annual climate periods during which precipitation and temperature influenced production. In forests, annual peak greenness (EVImax) was best predicted by 9‐month SPEI calculated in July (i.e., January–July). In shrublands and grasslands, EVImax was best predicted by SPEI in July through September, with little effect of the previous year's EVImax. Daily gross ecosystem production (GEP) derived from flux tower data yielded further insights into the complex interplay between precipitation and temperature. In forests, GEP was driven by cool‐season precipitation and constrained by warm‐season maximum temperature. GEP in both shrublands and grasslands was driven by summer precipitation and constrained by high daily summer maximum temperatures. In grasslands, there was a negative relationship between temperature and GEP in July, but no relationship in August and September. Consideration of sub‐annual climate conditions and the inclusion of the effect of temperature on the water balance allowed us to generalize the functional responses of vegetation to predicted future climate conditions. We conclude that across biomes, drought conditions during critical sub‐annual climate periods could have a strong negative impact on vegetation production in the southwestern United States.