bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of spin-gapless semiconductivity and half-metallicity in Ti2MnAl-based compounds
Authors: Lukashev P. , Kharel P. , Gilbert S. , Staten B. , Hurley N. , Fuglsby R. , Huh Y. , Valloppilly S. , Zhang W. , Yang K. , Skomski R. , Sellmyer D. J.
Published: April 2016

The increasing interest in spin-based electronics has led to a vigorous search for new materials that can provide a high degree of spin polarization in electron transport. An ideal candidate would act as an insulator for one spin channel and a conductor or semiconductor for the opposite spin channel, corresponding to the respective cases of half-metallicity and spin-gapless semiconductivity. Our first-principle electronic-structure calculations indicate that the metallic Heusler compound Ti2MnAl becomes half-metallic and spin-gapless semiconducting if half of the Al atoms are replaced by Sn and In, respectively. These electronic structures are associated with structural transitions from the regular cubic Heusler structure to the inverted cubic Heusler structure.
Microfluidic extensional rheometry using stagnation point flow
Authors: Haward S. J.
Published: April 2016

Characterization of the extensional rheometry of fluids with complex microstructures is of great relevance to the optimization of a wide range of industrial applications and for understanding various natural processes, biological functions, and diseases. However, quantitative measurement of the extensional properties of complex fluids has proven elusive to researchers, particularly in the case of low viscosity, weakly elastic fluids. For some time, microfluidic platforms have been recognized as having the potential to fill this gap and various approaches have been proposed. This review begins with a general discussion of extensional viscosity and the requirements of an extensional rheometer, before various types of extensional rheometers (particularly those of microfluidic design) are critically discussed. A specific focus is placed on microfluidic stagnation point extensional flows generated by cross-slot type devices, for which some important developments have been reported during the last 10 years. Additional emphasis is placed on measurements made on relevant biological fluids. Finally, the operating limits of the cross-slot extensional rheometer (chiefly imposed by the onset of elastic and inertial flow instabilities) are discussed.
Ultra-thin smart acoustic metasurface for low-frequency sound insulation
Authors: Zhang Hao , Xiao Yong , Wen Jihong , Yu Dianlong , Wen Xisen
Published: April 2016

Insulating low-frequency sound is a conventional challenge due to the high areal mass required by mass law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional mass law of sound insulation by 30 dB in the low frequency regime (<1000 Hz), with an ultra-light areal mass density (<1.6 kg/m2) and an ultra-thin thickness (1000 times smaller than the operating wavelength). The underlying physical mechanism of such extraordinary sound insulation performance is attributed to the infinite effective dynamic mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.
Low driving voltage band-filling-based III-V-on-silicon electroabsorption modulator
Authors: Huang Qiangsheng , Wu Yingchen , Ma Keqi , Zhang Jianhao , Xie Weiqiang , Fu Xin , Shi Yaocheng , Chen Kaixuan , He Jian-Jun , Van Thourhout Dries , Roelkens Gunther , Liu Liu , He Sailing
Published: April 2016

In this paper, a method for realizing a low driving voltage electroabsorption modulator based on the band-filling effect is demonstrated. The InP-based electroabsorption modulator is integrated using divinylsiloxane-bis-benzocyclobutene adhesive bonding on a silicon-on-insulator waveguide platform. When the electroabsorption modulator is forward biased, the band-filling effect occurs, which leads to a blue shift of the exciton absorption spectrum, while the absorption strength stays almost constant. In static operation, an extinction ratio of more than 20 dB with 100 mV bias variation is obtained in an 80 μm long device. In dynamic operation, 1.25 Gbps modulation with a 6.3 dB extinction ratio is obtained using only a 50 mV peak-to-peak driving voltage. The band-filling effect provides a method for realizing ultra-low-driving-voltage electroabsorption modulators.
Ultrafast and band-selective Auger recombination in InGaN quantum wells
Authors: Williams Kristopher W. , Monahan Nicholas R. , Koleske Daniel D. , Crawford Mary H. , Zhu X.-Y.
Published: April 2016

In InGaN quantum well based light-emitting diodes, Auger recombination is believed to limit the quantum efficiency at high injection currents. Here, we report the direct observation of carrier loss from Auger recombination on a sub-picosecond timescale in a single InGaN quantum well using time-resolved photoemission. Selective excitations of different valence sub-bands reveal that the Auger rate constant decreases by two orders of magnitude as the effective hole mass decreases, confirming the critical role of momentum conservation.
Oblique patterned etching of vertical silicon sidewalls
Authors: Bruce Burckel D. , Finnegan Patrick S. , David Henry M. , Resnick Paul J. , Jarecki Robert L.
Published: April 2016

A method for patterning on vertical silicon surfaces in high aspect ratio silicon topography is presented. A Faraday cage is used to direct energetic reactive ions obliquely through a patterned suspended membrane positioned over the topography. The technique is capable of forming high-fidelity pattern (100 nm) features, adding an additional fabrication capability to standard top-down fabrication approaches.
Effect of feeding whole-crop corn silage as dietary roughage on physiological and digestive response of sheep under heat exposure
Authors: Rahman Md. Mostafizar , Vinitchaikul Paramintra , Panthee Arvinda , Bi Xue , Sano Hiroaki
Published: April 2016

The present study was conducted to investigate the effect of feeding whole-crop corn silage (WCS) compared with mixed hay (MH) or grass silage (GS) on physiological and digestive responses of sheep at thermoneutral temperature (20°C) or exposed to heat (30°C). Six sheep were fed ad libitum with one of three diets in a replicated 3 × 3 Latin square design for 24 days. After 14 days’ adaptation, they were exposed to thermoneutral (20°C) and then heat exposure (30°C) for 5 days each. Rumen sample was collected on Day 4, whereas physiological response and nitrogen (N) balance were carried-out for three successive days in each exposure period. Respiration rate and rectal temperature of WCS-fed sheep were lower (P < 0.05) than of MH and GS fed sheep and both were higher (P < 0.01) during heat exposure. The intakes of dry matter (DM) and N and the digestibilities of N and neutral detergent fibre were lower (P < 0.05) for the WCS diet than for MH and GS diets and they did not differ between two temperature exposures. However, WCS-fed sheep had higher (P < 0.05) digestibilities of DM and organic matter, as well as metabolisable energy intake (M/D) than the sheep fed MH or GS diet, and there was no temperature effect on them. As DM and N intakes were lower for the WCS diet, the variables of rumen fermentation were also lower (P < 0.05) than the other two diets except propionate and butyrate concentrations, and they did not differ between temperature exposures except NH3 concentration. In conclusion, physiological responses were improved in the WCS diet and this approach thus shows promise for feeding heat-exposed animals. However, as results were inconsistent in terms of nutrient intake and digestibility, further work is needed and we suggest investigating the effect of feeding WCS with supplemented N.
New perspectives on the mineral nutrition of livestock grazing cereal and canola crops
Authors: Dove H. , Masters D. G. , Thompson A. N.
Published: April 2016

The grazing of cereal and canola crops during winter is an increasing component of grazing systems in southern Australia. The capacity of such crops to meet the requirements of young livestock and reproducing animals for sodium (Na), magnesium (Mg), calcium (Ca) and potassium (K) is reviewed. The growth responses of young stock to Na and/or Mg supplements when grazing wheat are discussed. These responses differ from ‘literature expectation’ in that they are rapid in onset and involve no clinical signs. We demonstrate that more insight about the variability in supplement response, both between and between crops species, is obtained when mineral contents are viewed from the perspective of their frequency distributions, rather than their mean values. The pivotal importance of high K concentration, low Na and the resultant K : Na ratio of forage is stressed, as is the interaction of these minerals in relation to Mg absorption. We also present frequency distributions for a range of mineral indices that ‘capture’ mineral interactions, including the ‘tetany index’, forage K :  (Na+Mg) ratio and dietary cation–anion difference. It is concluded that the last two indices warrant a much closer investigation. Possible effects of forage aluminium and organic acid contents are briefly discussed; these also deserve closer examination. As research in this area continues, it would be prudent to provide Na and/or Mg supplements for livestock grazing wheat and possibly oats and barley, and calcium supplements for livestock grazing oats or for reproducing animals grazing all three cereals.
Heterotrimeric G-protein shuttling via Gip1 extends the dynamic range of eukaryotic chemotaxis
Authors: Kamimura Yoichiro , Miyanaga Yukihiro , Ueda Masahiro
Published: April 2016

Significance

Eukaryotic chemotactic cells can recognize chemical gradients over a wide range of concentrations. This ability is physiologically important for numerous biological processes; however, its underlying mechanism is unknown. Here we report that the dynamic range of chemotaxis is extended to higher concentrations by gradient sensing achieved via regulation of trimeric G-protein shuttling between the cytosol and plasma membrane. G protein-interacting protein 1 (Gip1) regulates this intracellular G-protein translocation, which redistributes cytosolic G proteins to the plasma membrane along chemical gradients at high chemoattractant concentrations. This dynamic spatiotemporal regulation of trimeric G protein yields proper processing of receptor-mediated signaling.
PDGF-AB and 5-Azacytidine induce conversion of somatic cells into tissue-regenerative multipotent stem cells
Authors: Chandrakanthan Vashe , Yeola Avani , Kwan Jair C. , Oliver Rema A. , Qiao Qiao , Kang Young Chan , Zarzour Peter , Beck Dominik , Boelen Lies , Unnikrishnan Ashwin , Villanueva Jeanette E. , Nunez Andrea C. , Knezevic Kathy , Palu Cintia , Nasrallah Rabab , Carnell Michael , Macmillan Alex , Whan Renee , Yu Yan , Hardy Philip , Grey Shane T. , Gladbach Amadeus , Delerue Fabien , Ittner Lars , Mobbs Ralph , Walkley Carl R. , Purton Louise E. , Ward Robyn L. , Wong Jason W. H. , Hesson Luke B. , Walsh William , Pimanda John E.
Published: April 2016

Significance

In this report we describe the generation of tissue-regenerative multipotent stem cells (iMS cells) by treating mature bone and fat cells transiently with a growth factor [platelet-derived growth factor–AB (PDGF-AB)] and 5-Azacytidine, a demethylating compound that is widely used in clinical practice. Unlike primary mesenchymal stem cells, which are used with little objective evidence in clinical practice to promote tissue repair, iMS cells contribute directly to in vivo tissue regeneration in a context-dependent manner without forming tumors. This method can be applied to both mouse and human somatic cells to generate multipotent stem cells and has the potential to transform current approaches in regenerative medicine.
Long antibody HCDR3s from HIV-naïve donors presented on a PG9 neutralizing antibody background mediate HIV neutralization
Authors: Willis Jordan R. , Finn Jessica A. , Briney Bryan , Sapparapu Gopal , Singh Vidisha , King Hannah , LaBranche Celia C. , Montefiori David C. , Meiler Jens , Crowe James E.
Published: April 2016

Significance

When HIV neutralizing antibody (Ab) responses occur, they are often mediated by Abs with exceptional levels of somatic mutation. An exception are HIV neutralizing Abs that feature long heavy-chain complementarity-determining region 3 (HCDR3) regions, such as the Ab PG9. Relative to many other HIV broadly neutralizing Abs (bnAbs), PG9 has fewer somatic mutations than most potent bnAbs. Here we used deep-sequencing and computational methods to identify a panel of HCDR3 sequences in HIV-naïve donors that mediated binding and neutralization of HIV by mimicking the bnAb PG9 long HCDR3 region when expressed in the context of the rest of the PG9 antibody sequence. Thus, it may be possible for structure-based vaccine design efforts to engage long HCDR3s available in the HIV-naïve Ab repertoire and elicit a neutralizing response.
Pathogen receptor discovery with a microfluidic human membrane protein array
Authors: Glick Yair , Ben-Ari Ya’ara , Drayman Nir , Pellach Michal , Neveu Gregory , Boonyaratanakornkit Jim , Avrahami Dorit , Einav Shirit , Oppenheim Ariella , Gerber Doron
Published: April 2016

Significance

In this work, we report, to our knowledge, the first in vitro tool for host–pathogen screening that encompasses thousands of functional insoluble proteins—primarily transmembrane proteins—immobilized within a microfluidic device. We discovered previously unknown protein–pathogen interactions, and then selected interactions were further validated by conventional methods. Considering the tremendous difficulty in discovering pathogen receptors, this in vitro high-throughput approach is extremely important and efficient for receptor discovery and understanding pathogen tropism, with relevance to emerging human diseases.
The effect of gene interactions on the long-term response to selection
Authors: Paixão Tiago , Barton Nicholas H.
Published: April 2016

Significance

The role of gene interactions in the response to selection has long been a controversial subject; whereas some have claimed they are not relevant for adaptation, others have argued that their long-term effects are of high significance. In this manuscript, we derive simple and general predictions for the effect of gene interactions on the long-term response to selection in two extreme regimes. We show that, when the dynamics of allele frequencies are dominated by genetic drift, the long-term response is surprisingly simple, depending only on the initial components of the trait variance, regardless of the detailed genetic architecture. In the opposite regime, when selection dominates the dynamics of allele frequencies, the long-term response depends only on the genotype−phenotype.
Hall effect in quantum critical charge-cluster glass
Authors: Wu Jie , Bollinger Anthony T. , Sun Yujie , Božović Ivan
Published: April 2016

Significance

In cuprates, when doping is reduced superconductivity weakens and eventually disappears. The sample becomes “insulating” insofar that resistivity increases as the temperature is lowered, but the conductivity remains high, so the nature of this strange insulating state has been a puzzle. Here, we study the superconductor–insulator transition, improving the control of the doping level by 2 orders of magnitude and the sensitivity in probing transport fluctuations by 3 orders of magnitude. Our data reveal that at the lowest temperatures superconductivity competes with a charge-glass state. We propose that the latter is a glassy version of a charge density wave, and that it originates from strong localization due to charge–lattice coupling.
Population size does not explain past changes in cultural complexity
Authors: Vaesen Krist , Collard Mark , Cosgrove Richard , Roebroeks Wil
Published: April 2016

Significance

Archaeologists have long tried to understand why cultural complexity often changed in prehistory. Recently, a series of highly influential formal models have suggested that demography is the key factor. According to these models, the size of a population determines its ability to invent and maintain cultural traits. In this paper, we demonstrate that the models in question are flawed in two important respects: They use questionable assumptions, and their predictions are not supported by the available archaeological and ethnographic evidence. As a consequence, little confidence can be invested in the idea that demography explains the changes in cultural complexity that have been identified by archaeologists. An alternative explanation is required.
Functional network inference of the suprachiasmatic nucleus
Authors: Abel John H. , Meeker Kirsten , Granados-Fuentes Daniel , St. John Peter C. , Wang Thomas J. , Bales Benjamin B. , Doyle Francis J. , Herzog Erik D. , Petzold Linda R.
Published: April 2016

Significance

In mammals, circadian rhythms are controlled by a network of neurons in the brain. The structure of this network dictates organism-wide behavior and adaptation to the environment. We used a neurotoxin to desynchronize this circadian network and then used tools from information theory to determine which cells communicate to establish synchronization. Our results show that this functional network consists of two densely-connected cores, surrounded by sparsely connected shell regions. These findings represent the first time, to our knowledge, that this network has been examined at single cell resolution and show that the importance of these core network regions is independent of light input.
Polarized localization of voltage-gated Na
+
channels is regulated by concerted FGF13 and FGF14 action
Authors: Pablo Juan Lorenzo , Wang Chaojian , Presby Matthew M. , Pitt Geoffrey S.
Published: April 2016

Significance

Neurons concentrate voltage-gated sodium channels (VGSCs) in axons while limiting VGSCs in the somatodendritic compartment. This axonal concentration is important for efficient generation of the action potential, but it remains unclear what limits the concentration of VGSCs in the somatodendritic compartment. Here, we report that two highly similar molecules, FGF13 and FGF14, collaborate to maintain proper VGSC localization. FGF13 is a critical mediator of the process that keeps VGSCs low in the somatodendritic compartment, whereas FGF14 is an important regulator of VGSC localization to the axon.
Importance of ocean salinity for climate and habitability
Authors: Cullum Jodie , Stevens David P. , Joshi Manoj M.
Published: April 2016

Significance

The habitability of the growing number of confirmed exoplanets is a question of wide interest and importance. A key factor determining habitability is planetary climate, which is influenced heavily by the presence of liquid water oceans, and in particular, the heat transported around the planet by these oceans. Here the impact of average ocean salinity, a key property in determining the density of water, on ocean state is investigated. It is shown that oceans that have sufficiently different average salinities to Earth consist of circulations of opposite direction: sinking in the tropics, filling the deep ocean with warm water, and ultimately warming the polar regions. Variations in ocean properties can therefore extend the range of exoplanet habitability.
Real-time monitoring of metabolic function in liver-on-chip microdevices tracks the dynamics of mitochondrial dysfunction
Authors: Bavli Danny , Prill Sebastian , Ezra Elishai , Levy Gahl , Cohen Merav , Vinken Mathieu , Vanfleteren Jan , Jaeger Magnus , Nahmias Yaakov
Published: April 2016

Significance

Microfluidic organ-on-a-chip technology is poised to replace animal toxicity testing, but thus far has demonstrated few advantages over traditional methods. Here we demonstrate a sensor-integrated platform permitting real-time tracking of the dynamics of metabolic adaptation to mitochondrial dysfunction. Our approach permits detection of chemical toxicity before any effects on cell or tissue viability can be observed.
Test of the invasive pathogen hypothesis of bumble bee decline in North America
Authors: Cameron Sydney A. , Lim Haw Chuan , Lozier Jeffrey D. , Duennes Michelle A. , Thorp Robbin
Published: April 2016

Significance

Wild bumble bees are experiencing population declines globally. Causes of declines in North American populations are unclear, although declining species are more frequently infected by the pathogenNosema bombi. A widely accepted hypothesis suggests that contact with European species during domestication led to the introduction of exoticN. bombi. By screening museum specimens, we show thatN. bombiprevalence increased significantly in declining species in the early to mid-1990s, coincident withN. bombioutbreaks in North American commercial stocks. There is no evidence that exoticNosemastrains were introduced from Europe. Regardless of geographic origins, the temporal connection betweenN. bombiepizootics in commercialBombusstocks and increases in wild populations suggests a substantial risk of pathogen transmission with domestication.
Ang-2/VEGF bispecific antibody reprograms macrophages and resident microglia to anti-tumor phenotype and prolongs glioblastoma survival
Authors: Kloepper Jonas , Riedemann Lars , Amoozgar Zohreh , Seano Giorgio , Susek Katharina , Yu Veronica , Dalvie Nisha , Amelung Robin L. , Datta Meenal , Song Jonathan W. , Askoxylakis Vasileios , Taylor Jennie W. , Lu-Emerson Christine , Batista Ana , Kirkpatrick Nathaniel D. , Jung Keehoon , Snuderl Matija , Muzikansky Alona , Stubenrauch Kay G. , Krieter Oliver , Wakimoto Hiroaki , Xu Lei , Munn Lance L. , Duda Dan G. , Fukumura Dai , Batchelor Tracy T. , Jain Rakesh K.
Published: April 2016

Significance

Improving survival of patients with glioblastoma (GBM) using antiangiogenic therapy remains a challenge. In this study we show that dual blockade of angiopoietin-2 and vascular endothelial growth factor delays tumor growth and enhances survival benefits through reprogramming of tumor-associated macrophages toward an antitumor phenotype as well as by pruning immature tumor vessels. The antitumor immunomodulatory potential of this dual blockade supports clinical testing of this approach for GBM with other immunotherapeutic approaches such as checkpoint blockers.
Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change
Authors: Hume Benjamin C. C. , Voolstra Christian R. , Arif Chatchanit , D’Angelo Cecilia , Burt John A. , Eyal Gal , Loya Yossi , Wiedenmann Jörg
Published: April 2016

Significance

Reef corals in the Persian/Arabian Gulf (PAG) withstand exceptionally high salinity and regular summer temperatures of ∼35 °C that kill conspecifics elsewhere. These thermotolerant communities established themselves within only ∼6,000 y under the pressure of rapid climate change and can therefore inform how other coral reefs may respond to global warming. One key to the thermotolerance of PAG corals is their symbiosis with
Symbiodinium thermophilum
. Phylogeographic evidence indicates that this symbiont represents a stress-tolerant subpopulation of an ancestral taxonomic group with surprising genetic diversity that exists at barely detectable levels outside the PAG. Our results highlight the critical importance of present-day biodiversity for future adaptation to climate change for coral reefs and ecosystems in general.
Prostate epithelial cell of origin determines cancer differentiation state in an organoid transformation assay
Authors: Park Jung Wook , Lee John K. , Phillips John W. , Huang Patrick , Cheng Donghui , Huang Jiaoti , Witte Owen N.
Published: April 2016

Significance

This study demonstrates that both primary human basal and luminal epithelial cells are cells of origin for prostate cancer through the use of a prostate organoid culture system. This technology enables the monitoring of early stages of prostate tumorigenesis in vitro and the interrogation of human prostate epithelial populations with synonymous oncogenic stimuli. The combination of c-Myc overexpression and activation of the PI3K/AKT pathway drives high-grade prostate adenocarcinoma in basal cell-derived tumors; however, the same oncogenic stress causes low-grade prostate adenocarcinoma in luminal cell-derived tumors. These findings indicate inherent context-specific and lineage-dependent differences in the response of human prostate epithelial cells to oncogenic stimuli.
Influence of quenching rate on microstructure and dimensional stability of Al–Cu–Mg–Si alloy
Authors: Dong Y.-B. , Shao W.-Z. , Jiang J.-T. , Chao D.-Y. , Zhen L.
Published: April 2016

With the development of precision instrument in space industry fields, increasing attention has been devoted to improve the dimensional stability of structural materials. In this study, the influence of quenching rate on microstructure, residual stress and dimensional stability of Al–Cu–Mg–Si alloy was studied. The results showed that boil water quenching resulted in very low residual stress but unsatisfactory mechanical properties. In contrast, low residual stress and good mechanical property were achieved by quenching the sample into 80°C water. Residual stress has a significant influence on the thermal dimensional stability. The thermal dimensional stability of sample quenched in 80°C water is better than that of sample quenched in 20°C water due to lower residual stress in 80°C water-quenched sample.
Oral administration of Aloe vera gel powder prevents UVB-induced decrease in skin elasticity via suppression of overexpression of MMPs in hairless mice
Authors: Saito Marie , Tanaka Miyuki , Misawa Eriko , Yao Ruiquing , Nabeshima Kazumi , Yamauchi Kouji , Abe Fumiaki , Yamamoto Yuki , Furukawa Fukumi
Published: April 2016

This study reports the effects of oral Aloe vera gel powder (AVGP) containing Aloe sterols on skin elasticity and the extracellular matrix in ultraviolet B (UVB)-irradiated hairless mice. Ten-week-old hairless mice were fed diets containing 0.3% AVGP for 8 weeks and irradiated UVB for 6 weeks. Mice treated with AVGP showed significant prevention of the UVB-induced decrease in skin elasticity. To investigate the mechanism underlying this suppression of skin elasticity loss, we measured the expression of matrix metalloproteinase (MMP)-2, -9, and -13. AVGP prevented both the UVB-induced increases in MMPs expressions. Moreover, we investigated hyaluronic acid (HA) content of mice dorsal skin and gene expression of HA synthase-2 (Has2). In the results, AVGP oral administration prevented UVB-induced decreasing in skin HA content and Has2 expression and attenuates the UVB-induced decrease in serum adiponectin, which promotes Has2 expression. These results suggested that AVGP has the ability to prevent the skin photoaging.
Age Differences in the Structured Assessment of Violence Risk in Youth (SAVRY)
Authors: Childs Kristina K. , Frick Paul J.
Published: April 2016

This study examined age differences in (1) the latent structure of the SAVRY, (2) the correspondence among structured professional judgments of risk and an empirically-derived measure, and (3) the SAVRY's predictive validity for probation outcomes. The sample consisted of 177 juveniles placed on probation. Analyses were conducted on two separate age groups: ages 13–15 and 16–18. We found that the SAVRY measured “risk” similarly across age (i.e., invariant latent structures) and that structured judgments of risk corresponded with the empirically-derived measure across both age groups. However, findings regarding the predictive validity of the SAVRY for probation outcomes were mixed. These findings provide strong support for the measurement and construct validity of the SAVRY across age and highlight the need for additional research on age differences in the strength of its predictive validity.
On the efficient acceleration of clouds in active galactic nuclei
Authors: Waters Tim , Proga Daniel
Published: April 2016

In the broad line region of active galactic nuclei (AGN), acceleration occurs naturally when a cloud condenses out of the hot confining medium due to the increase in line opacity as the cloud cools. However, acceleration by radiation pressure is not very efficient when the flux is time-independent, unless the flow is 1D. Here, we explore how acceleration is affected by a time-varying flux, as AGN are known to be highly variable. If the period of flux oscillations is longer than the thermal time-scale, we expect the gas to cool during the low flux state, and therefore line opacity should quickly increase. The cloud will receive a small kick due to the increased radiation force. We perform hydrodynamical simulations using athena to confirm this effect and quantify its importance. We find that despite the flow becoming turbulent in 2D due to hydrodynamic instabilities, a 20 per cent modulation of the flux leads to a net increase in acceleration – by more than a factor of 2 – in both 1D and 2D. We show that this acceleration is sufficient to produce the observed line widths, although we only consider optically thin clouds. We discuss the implications of our results for photoionization modelling and reverberation mapping.
The tangential velocity of M31: CLUES from constrained simulations
Authors: Carlesi Edoardo , Hoffman Yehuda , Sorce Jenny G. , Gottlöber Stefan , Yepes Gustavo , Courtois Hélène , Tully R. Brent
Published: April 2016

Determining the precise value of the tangential component of the velocity of M31 is a non-trivial astrophysical issue that relies on complicated modelling. This has recently lead to conflicting estimates, obtained by several groups that used different methodologies and assumptions. This Letter addresses the issue by computing a Bayesian posterior distribution function of this quantity, in order to measure the compatibility of those estimates with Λ cold dark matter (ΛCDM). This is achieved using an ensemble of Local Group (LG) look-alikes collected from a set of constrained simulations (CSs) of the local Universe, and a standard unconstrained ΛCDM. The latter allows us to build a control sample of LG-like pairs and to single out the influence of the environment in our results. We find that neither estimate is at odds with ΛCDM; however, whereas CSs favour higher values of vtan, the reverse is true for estimates based on LG samples gathered from unconstrained simulations, overlooking the environmental element.
Unusual rainbow and white rainbow: A new auroral candidate in oriental historical sources
Authors: Hayakawa Hisashi , Isobe Hiroaki , Davis Kawamura Akito , Tamazawa Harufumi , Miyahara Hiroko , Kataoka Ryuho
Published: April 2016

Solar activity has been recorded as auroras or sunspots in various historical sources. These records are of great importance for investigating both long-term solar activities and extremely intense solar flares. According to previous studies, they were recorded as “vapor,” “cloud,” or “light,” especially in oriental historical sources; however, this terminology has not been discussed adequately, and remains still quite vague. In this paper, we suggest the possibility of using “unusual rainbow” and “white rainbow” as candidates of historical auroras in oriental historical sources, and examine if this is probable. This discovery will help us to make more comprehensive historical auroral catalogues, and require us to add these terms to auroral candidates in oriental historical sources.
Synthetic miR-16-5p does not act as a reverse transcriptase co-factor to enhance detection of small RNA
Authors: McAlexander Melissa A. , Witwer Kenneth W.
Published: April 2016

Failure to detect low-abundance microRNAs (miRNAs), for example, in circulating plasma, may occur for a variety of reasons, including presence of enzyme inhibitors. Recently, we received the unusual but intriguing suggestion that miR-16-5p acts as a co-factor of reverse transcriptases, facilitating more efficient reverse transcription of miRNAs and thus enhanced detection of low-abundance miRNAs. We tested this hypothesis by incubating reverse transcriptase with several concentrations of synthetic miR-16-5p and then performing stem-loop RT-qPCR with serial dilutions of miRNA osa-MIR168a. Our results do not support a role for miR-16 as a co-factor of reverse transcriptase.
A hydrostable and twofold interpenetrating three-dimensional zinc–organic framework with rob topology based on 4,4′-oxydibenzoate and 3,3′-dimethyl-4,4′-bipyridine ligands
Authors: Liang Feng-Lan , Ma De-Yun , Qin Liang
Published: April 2016

Metal–organic frameworks (MOFs) are a new class of porous materials that have received widespread attention due to their potential applications in gas storage and/or separation, catalysis, luminescence, and so on. The title compound, poly[[(μ2-3,3′-dimethyl-4,4′-bipyridine-κ2N:N′)bis(μ4-4,4′-oxydibenzoato-κ4O:O′:O′′:O′′′)dizinc] tetrahydrate], {[Zn2(C14H8O5)2(C12H12N2)]·4H2O}n, has been prepared by the solvothermal assembly of Zn(NO3)2·6H2O, 4,4′-oxydi(benzoic acid) and 3,3′-dimethyl-4,4′-bipyridine. The two ZnIIatoms adopt the same five-coordinated distorted square-pyramidal geometry (i.e.ZnO4N), bonding to four O atoms from four different 4,4′-oxydibenzoate (oba) ligands and one N atom from a 3,3′-dimethyl-4,4′-bipyridine (dmbpy) ligand. The supramolecular secondary building unit (SBU) is a paddle-wheel [Zn2(COO)4] unit and these units are linked by oba ligands within the layer to form a two-dimensional net parallel to thebaxis, with the dmbpy ligands pointing alternately up and down, which is further extended by dmbpy ligands to form a three-dimensional framework withrobtopology. The single net leaves voids that are filled by mutual interpenetration of an independent equivalent framework in a twofold interpenetrating architecture. The title compound shows thermal stability up to 673 K and is stable in aqueous solutions in the pH range 5–9. Excitation and luminescence data observed at room temperature show that it emits a bright-blue fluorescence.
Crystal structures of five new substituted tetrahydro-1-benzazepines with potential antiparasitic activity
Authors: Macías Mario A. , Acosta Lina M. , Sanabria Carlos M. , Palma Alirio , Roussel Pascal , Gauthier Gilles H. , Suescun Leopoldo
Published: April 2016

Tetrahydro-1-benzazepines have been described as potential antiparasitic drugs for the treatment of chagas disease and leishmaniasis, two of the most important so-called `forgotten tropical diseases' affecting South and Central America, caused byTrypanosoma cruziandLeishmania chagasiparasites, respectively. Continuing our extensive work describing the structural characteristics of some related compounds with interesting biological properties, the crystallographic features of three epoxy-1-benzazepines, namely (2SR,4RS)-6,8-dimethyl-2-(naphthalen-1-yl)-2,3,4,5-tetrahydro-1H-1,4-epoxy-1-benzazepine, (1), (2SR,4RS)-6,9-dimethyl-2-(naphthalen-1-yl)-2,3,4,5-tetrahydro-1H-1,4-epoxy-1-benzazepine, (2), and (2SR,4RS)-8,9-dimethyl-2-(naphthalen-1-yl)-2,3,4,5-tetrahydro-1H-1,4-epoxy-1-benzazepine, (3), all C22H21NO, and two 1-benzazepin-4-ols, namely 7-fluoro-cis-2-[(E)-styryl]-2,3,4,5-tetrahydro-1H-1-benzazepin-4-ol, C18H18FNO, (4), and 7-fluoro-cis-2-[(E)-pent-1-enyl]-2,3,4,5-tetrahydro-1H-1-benzazepin-4-ol, C15H20FNO, (5), are described. Some peculiarities in the crystallization behaviour were found, involving significant variations in the crystalline structures as a result of modest changes in the peripheral substituents in (1)–(3) and the occurrence of discrete disorder due to the molecular overlay of enantiomers with more than one conformation in (5). In particular, an interesting phase change on cooling was observed for compound (5), accompanied by an approximate fourfold increase of the unit-cell volume and a change of theZ′ value from 1 to 4. This transition is a consequence of the partial ordering of the pentenyl chains in half of the molecules breaking half of the \overline{3} symmetry axes observed in the room-temperature structure of (5). The structural assembly in all the title compounds is characterized by not only (N,O)—H...(O,N) hydrogen bonds, but also by unconventional C—H...O contacts, resulting in a wide diversity of packing.
Crystal structure of levomepromazine maleate
Authors: Gál Gyula Tamás , May Nóra Veronika , Bombicz Petra
Published: April 2016

The asymmetric unit of the title salt, C19H25N2OS+·C4H3O4−[systematic name: (S)-3-(2-methoxyphenothiazin-10-yl)-N,N,2-trimethylpropanaminium hydrogen maleate], comprises two (S)-levomepromazine cations and two hydrogen maleate anions. The conformations of the two cations are similar. The major difference relates to the orientation of the methoxy substituent at the phenothiazine ring system. The crystal components form a three-dimensional supramolecular networkviaN—H...O, C—H...O and C—H...π interactions. A comparison of the conformations of the levomepromazine cations with those of the neutral molecule and similar protonated molecules reveals significant conformational flexibility of the phenothiazine ring system and the substituent at the phenothiazine N atom.
A purple odyssey: synthesis and structure of 3-amino-4-hydroxy-6-oxocyclohexa-2,4-dien-1-iminium chloride monohydrate
Authors: Plater M. John , Harrison William T. A.
Published: April 2016

In the cation of the title hydrated molecular salt, C6H7N2O2+·Cl−·H2O, the six-membered ring shows unequal bond lengths consistent with delocalization of electrons over two separate 6π systems with single bonds between them. In the crystal, the components are linked by N—H...Cl, N—H...O, O—H...Cl and O—H...O hydrogen bonds, generating double layers propagating in (100).
Crystal structure of sodium (1S)-D-lyxit-1-ylsulfonate
Authors: Haines Alan H. , Hughes David L.
Published: April 2016

The title compound, Na+·C5H11O8S−[systematic name: sodium (1S,2S,3S,4R)-1,2,3,4,5-pentahydroxypentane-1-sulfonate], is formed by reaction of D-lyxose with sodium bisulfite (sodium hydrogen sulfite) in water. The anion has an open-chain structure in which one of the oxygen atoms of the sulfonate residue, the S atom, the C atoms of the sugar chain and the O atom of the hydroxymethyl group form an essentially planar zigzag chain with the corresponding torsion angles lying between 179.80 (11) and 167.74 (14)°. A three-dimensional bonding network exists in the crystal structure involving hexacoordination of sodium ions by O atoms, three of which are provided by a single D-lyxose–sulfonate unit and the other three by two sulfonate groups and one hydroxymethyl group, each from separate units of the adduct. Extensive intermolecular O—H...O hydrogen bonding supplements this bonding network.
(1S,3R,8R,9S,10R)-2,2-Dichloro-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodecan-9-yl 4-methylbenzene-1-sulfonate
Authors: Benharref Ahmed , El Ammari Lahcen , Saadi Mohamed , Oukhrib Abdelouahd , Berraho Moha
Published: April 2016

The title compound, C23H31Cl2O3S, was synthesized in three steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from essential oil of the Atlas cedar (Cedrus atlantica). The fused six- and seven-membered rings have boat conformations: the dihedral angle between the mean planes of the rings is 88.03 (12)%. The absolute structure was established unambiguously from anomalous dispersion effects. There are no directional interactions in the crystal.
Bis[S-hexyl (E)-3-(4-methoxybenzylidene)dithiocarbazato-κ2N3,S]palladium(II)
Authors: Zangrando E. , Begum M. S. , Howlader M. B. H. , Sheikh M. C. , Miyatake R.
Published: April 2016

In the title complex, [Pd(C15H21N2OS2)2], the PdIIion is located on a crystallographic inversion center. The two Schiff base ligands in a deprotonated imino thiolate form chelate the metal atomviathe azomithine N and thiolate S atoms in atrans-square-planar configuration as imposed by the crystal symmetry. The complex has an approximately planar geometry with the exception of the hexyl chains; the mean plane of the five-membered chelate ring makes a dihedral angle of 15.43 (5)° with the benzene ring. In the crystal, the complex molecules are stacked along theaaxis.
Ethyl 4-(4-chlorophenyl)-5-cyano-2-methyl-6-sulfanylidene-1,6-dihydropyridine-3-carboxylate
Authors: Mague Joel T. , Mohamed Shaaban K. , Akkurt Mehmet , Bakhite Etify A. , Albayati Mustafa R.
Published: April 2016

In the title compound, C16H13ClN2O2S, the dihedral angle between the 4-chlorophenyl ring and the pyridine ring is 63.53 (6)°. There is an intramolecular C—H...O contact present. In the crystal, molecules are linked by pairs of N—H...S hydrogen bonds, forming inversion dimers. The dimers are linked by C—H...O and C—H...N hydrogen bonds, forming slabs parallel to theabplane.
1,1′-(Hexane-1,6-diyl)bis(indoline-2,3-dione)
Authors: Qachchachi Fatima Zahrae , Kandri Rodi Youssef , Haoudi Amal , Essassi El Mokhtar , Capet Frédéric , Zouihri Hafid
Published: April 2016

The molecule of the title compound, C22H20N2O4, is situated on a crystallographic centre of symmetry. The two indoline-2,3-dione fragments are linked by a hexylene group at each N atom. In the crystal, supramolecular layers propagating in theacplane are formedviaC—H...O hydrogen bonds.
Designs and methods in school improvement research: a systematic review
Authors: Feldhoff Tobias , Radisch Falk , Bischof Linda Marie
Published: April 2016

Purpose

– The purpose of this paper is to focus on challenges faced by longitudinal quantitative analyses of school improvement processes and offers a systematic literature review of current papers that use longitudinal analyses. In this context, the authors assessed designs and methods that are used to analyze the relation between school improvement processes and student outcomes. Based on this the authors point out to what extent the papers consider different aspects of the complex nature of school improvement (e.g. multilevel structure, indirect and nonlinear effects, reciprocity). The choice of study designs and methods of analysis substantially determines which aspects of this complexity are taken into account.

Design/methodology/approach

– The authors searched in four international high-impact journals and in ERIC for articles reporting longitudinal school improvement studies. The database of the review consisted of a total of 428 journal articles. In total, 13 of the 428 papers met the selection criteria and were analyzed in detail.

Findings

– The analyzed papers use a wide range of designs and methodological approaches. They support the assumption that sophisticated quantitative longitudinal designs and methods can be applied effectively in school improvement research. However, considering the complexity of school improvement is accompanied by high demands on designs and methods. Due to this none of the papers met the standards applied in this review completely.

Research limitations/implications

– In particular, further research is needed to consider a long period of observation, reciprocal indirect and nonlinear processes in a multilevel structure. Moreover, research is required for a better and unambiguous theoretical foundation and empirical validation of the number of and intervals between measurement points.

Practical implications

– If more consideration is given to the complex nature of school improvement in future studies, the broader knowledge base will allow a better understanding of the dynamic relation of school improvement and student learning. It would thus be possible to make more appropriate recommendations for the support of school improvement practice.

Originality/value

– The original contribution of the paper is to show which aspects of the complexity of school improvement processes – and to what extent – are currently addressed in designs and methods of analysis applied in quantitative longitudinal studies that investigate the relation between schools’ capacity to managing change and student outcomes. Additionally the authors aim at deriving need for further research and giving guidelines how designs and methods in further studies can reflect the complexity appropriately. It is highly important to consider all aspects of this complexity to describe and understand the dynamic relation of school improvement processes and student outcomes.
What matters more? The impact of industry and organizational factors on organizational culture
Authors: Chaudhry Anjali , Yuan Ling , Hu Jia , Cooke Robert A.
Published: April 2016

Purpose

– Writings on organizational culture suggest that cultural values and norms are influenced by factors at the organizational, industry, and societal levels. While the effects of societal and organizational factors have been researched extensively, those of industry factors have not received commensurate attention. The purpose of this paper is to investigate the relative importance of industry vs organizational variables in explaining the cultural norms reported by individuals within organizations.

Design/methodology/approach

– The effects of two industry characteristics, (growth rate and research and development intensity) and two sets of organizational factors (leadership behaviors and human resource practices) on the strength of constructive, passive/defensive, and aggressive/defensive organizational cultural norms were investigated.

Findings

– Results of hierarchical linear modeling analysis of survey data from 3,245 respondents in 424 organizations in 12 different industries revealed significant between-organization variation but no significant between-industry variation in the three types of cultural norms measured. Furthermore, while industry-level factors were unrelated to culture, significant variance in the culture measures was explained by leadership behaviors and human resource practices (use of rewards and fairness of performance appraisal).

Research limitations/implications

– The strength of cultural norms and expectations within an organization evolve in response to attributes specific to the organization and do not necessarily reflect industry characteristics. The results indicate that organizations using surveys to assess their cultures may learn as much (if not more) by comparing their feedback to data on organizations across a spectrum of industries as opposed to organizations exclusively in their own industry.

Originality/value

– Most of the frameworks developed to examine and describe the cultures of organizations delineate specific dimensions or types that are assumed to be relevant to all organizations regardless of the industries within which they operate. The purpose of this paper was to explore the validity of this assumption by investigating the relative impact of industry and organizational factors on organizational culture.