bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient photoresponse of nitrogen-doped ultrananocrystalline diamond electrodes in saline solution
Authors: Ahnood Arman , Simonov Alexandr N. , Laird Jamie S. , Maturana Matias I. , Ganesan Kumaravelu , Stacey Alastair , Ibbotson Michael R. , Spiccia Leone , Prawer Steven
Published: March 2016

Beyond conventional electrically-driven neuronal stimulation methods, there is a growing interest in optically-driven approaches. In recent years, nitrogen-doped ultrananocrystalline diamond (N-UNCD) has emerged as a strong material candidate for use in electrically-driven stimulation electrodes. This work investigates the electrochemical activity of N-UNCD in response to pulsed illumination, to assess its potential for use as an optically-driven stimulation electrode. Whilst N-UNCD in the as-grown state exhibits a weak photoresponse, the oxygen plasma treated film exhibits two orders of magnitude enhancement in its sub-bandgap open circuit photovoltage response. The enhancement is attributed to the formation of a dense network of oxygen-terminated diamond nanocrystals at the N-UNCD surface. Electrically connected to the N-UNCD bulk via sub-surface graphitic grain boundaries, these diamond nanocrystals introduce a semiconducting barrier between the sub-surface graphitic semimetal and the electrolyte solution, leading to a photovoltage under irradiation with wavelengths of λ = 450 nm and shorter. Within the safe optical exposure limit of 2 mW mm−2, charge injection capacity of 0.01 mC cm−2 is achieved using a 15 × 15 μm electrode, meeting the requirements for extracellular and intercellular stimulation. The nanoscale nature of processes presented here along with the diamond's biocompatibility and biostability open an avenue for the use of oxygen treated N-UNCD as optically driven stimulating electrodes.
A multiple gap plasma cathode electron gun and its electron beam analysis in self and trigger breakdown modes
Authors: Kumar Niraj , Pal Dharmendra Kumar , Jadon Arvind Singh , Pal Udit Narayan , Rahaman Hasibur , Prakash Ram
Published: March 2016

In the present paper, a pseudospark discharge based multiple gap plasma cathode electron gun is reported which has been operated separately in self and trigger breakdown modes using two different gases, namely, argon and hydrogen. The beam current and beam energy have been analyzed using a concentric ring diagnostic arrangement. Two distinct electron beams are clearly seen with hollow cathode and conductive phases. The hollow cathode phase has been observed for ∼50 ns where the obtained electron beam is having low beam current density and high energy. While in conductive phase it is high current density and low energy electron beam. It is inferred that in the hollow cathode phase the beam energy is more for the self breakdown case whereas the current density is more for the trigger breakdown case. The tailor made operation of the hollow cathode phase electron beam can play an important role in microwave generation. Up to 30% variation in the electron beam energy has been achieved keeping the same gas and by varying the breakdown mode operations. Also, up to 32% variation in the beam current density has been achieved for the trigger breakdown mode at optimized trigger position by varying the gas type.
Thermodynamic guiding principles in selective synthesis of strontium iridate Ruddlesden-Popper epitaxial films
Authors: Nishio Kazunori , Hwang Harold Y. , Hikita Yasuyuki
Published: March 2016

We demonstrate the selective fabrication of Ruddlesden-Popper (RP) type SrIrO3, Sr3Ir2O7, and Sr2IrO4 epitaxial thin films from a single SrIrO3 target using pulsed laser deposition (PLD). We identified that the growth conditions stabilizing each phase directly map onto the phase diagram expected from thermodynamic equilibria. This approach allows precise cation stoichiometry control as evidenced by the stabilization of single phase Sr3Ir2O7 for the first time, overcoming the close thermodynamic stability between neighboring RP phases. Despite the non-equilibrium nature of PLD, these results highlight the importance of thermodynamic guiding principles to strategically synthesize the targeted phase in complex oxide thin films.
Statistical correction of atom probe tomography data of semiconductor alloys combined with optical spectroscopy: The case of Al0.25Ga0.75N
Authors: Rigutti L. , Mancini L. , Hernández-Maldonado D. , Lefebvre W. , Giraud E. , Butté R. , Carlin J. F. , Grandjean N. , Blavette D. , Vurpillot F.
Published: March 2016

The ternary semiconductor alloy Al0.25Ga0.75N has been analyzed by means of correlated photoluminescence spectroscopy and atom probe tomography (APT). We find that the composition measured by APT is strongly dependent on the surface electric field, leading to erroneous measurements of the alloy composition at high field, due to the different evaporation behaviors of Al and Ga atoms. After showing how a biased measurement of the alloy content leads to inaccurate predictions on the optical properties of the material, we develop a correction procedure which yields consistent transition and localization energies for the alloy photoluminescence.
Anomalous behavior of 1/f noise in graphene near the charge neutrality point
Authors: Takeshita Shunpei , Matsuo Sadashige , Tanaka Takahiro , Nakaharai Shu , Tsukagoshi Kazuhito , Moriyama Takahiro , Ono Teruo , Arakawa Tomonori , Kobayashi Kensuke
Published: March 2016

We investigate the noise in single layer graphene devices from equilibrium to far-from equilibrium and found that the 1/f noise shows an anomalous dependence on the source-drain bias voltage (VSD). While the Hooge's relation is not the case around the charge neutrality point, we found that it is recovered at very low VSD region. We propose that the depinning of the electron-hole puddles is induced at finite VSD, which may explain this anomalous noise behavior.
Giant nonlinearity in a superconducting sub-terahertz metamaterial
Authors: Savinov V. , Delfanazari K. , Fedotov V. A. , Zheludev N. I.
Published: March 2016

We report a superconducting sub-THz metamaterial operating in a CW-regime, which exhibits a record-breaking resonant third-order nonlinearity with effective n2∼10 cm2/W. The nonlinear response is caused by the radiation-induced resistive heating, suppressing the superconductivity in the nano-scale constrictions of the structure's meta-molecules. The nonlinearity has a relaxation time of 25 μs and leads to a substantial change of the amplitude and phase of the transmitted radiation at intensities of only 500 μW/cm2.
Crystallographic alignment in the recombination stage in d-HDDR process of Nd-Fe-B-Ga-Nb powders
Authors: Horikawa Takashi , Matsuura Masashi , Sugimoto Satoshi , Yamazaki Masao , Mishima Chisato
Published: March 2016

Nd-Fe-B-Ga-Nb magnetic powder was subjected to the dynamic hydrogen disproportionation desorption recombination treatment. For samples disproportionated at both 30 and 100 kPa of hydrogen pressure, the changes in the microstructure and grain orientation during recombination process were investigated. It was observed that even during the recombination process, the orientation relationship was maintained between α-Fe and NdH2+x grains formed after the disproportionation treatment at 30 kPa of hydrogen pressure, [110]α-Fe // [110]NdH2+x, (-110)α-Fe // (-220)NdH2+x. Additionally, the alignment of recombined Nd2Fe14BHy grains became clear after 30 min of DR treatment showing following orientation relationship: (001)Nd2Fe14BHy // (110)α-Fe and (110)NdH2+x. In contrast, such a relationship was not observed in the sample disproportionated at 100 kPa of hydrogen pressure. This difference in the degree of alignment was also confirmed by measuring the magnetic property of the respective samples.
Controlled motion of domain walls in submicron amorphous wires
Authors: Ţibu Mihai , Lostun Mihaela , Allwood Dan A. , Rotărescu Cristian , Atiţoaie Alexandru , Lupu Nicoleta , Óvári Tibor-Adrian , Chiriac Horia
Published: March 2016

Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB) system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse.
Investigation of optimal route to fabricate submicron-sized Sm2Fe17 particles with reduction-diffusion method
Authors: Okada Shusuke , Takagi Kenta , Ozaki Kimihiro
Published: March 2016

Submicron-sized Sm2Fe17 powder samples were fabricated by a non-pulverizing process through reduction-diffusion of precursors prepared by a wet-chemical technique. Three precursors having different morphologies, which were micron-sized porous Sm-Fe oxide-impregnated iron nitrate, acicular goethite impregnated-samarium nitrate, and a conventional Sm-Fe coprecipitate, were prepared and subjected to hydrogen reduction and reduction-diffusion treatment to clarify whether these precursors could be convert to Sm2Fe17 without impurity phases and which precursor is the most attractive for producing submicron-sized Sm2Fe17 powder. As a result, all three precursors were successfully converted to Sm2Fe17 powders without impurity phases, and the synthesis route using iron-oxide particle-impregnated samarium oxide was revealed to have the greatest potential among the three routes.
Effect of cooling rate on magnetostriction gradients of Tb0.27Dy0.73Fe1.95 alloys solidified in high magnetic field gradients
Authors: Liu Tie , Gao Peng-Fei , Dong Meng , Xiao Yu-Bao , Wang Qiang
Published: March 2016

In this work, Tb0.27Dy0.73Fe1.95 alloys were solidified in a high magnetic field gradient (8.8 T, -565 T2/m) at various cooling rates. Changes in the magnetostriction, crystal orientation, and magnetization of the alloys were investigated. The application of the magnetic field gradient has a strong influence on the magnetostrictive performance. At lower cooling rates, the maximum magnetostriction increases gradually with depth from the top surface of the alloys. However, the effect of the magnetic field gradient is strongly dependent on the cooling rate. With increasing cooling rate, the magnetostriction gradient decreases. The magnetization measurement shows that the saturation magnetization at lower cooling rates increases gradually with depth from the top surface of the alloys. However, with increasing cooling rate, the increase in the saturation magnetization is reduced. The XRD measurement results show that the orientation behavior of the (Tb, Dy)Fe2 phase exhibits a continuous change throughout the alloys at lower cooling rates, but is almost unchanged at higher cooling rates. The change in the magnetostriction of the alloys can be attributed to the changes in crystal orientation and the amount of the (Tb, Dy)Fe2 phase in the alloys caused by both the magnetic field gradient and cooling rate.
Status and Habitat Use of Scaphirhynchus Sturgeons in an Important Fluvial Corridor: Implications for River Habitat Enhancement
Authors: Hintz William D. , Glover David C. , Garvey James E. , Killgore K. Jack , Herzog David P. , Spier Timothy W. , Colombo Robert E. , Hrabik Robert A.
Published: March 2016

In the central United States, recovery efforts for populations of the federally endangered Pallid Sturgeon Scaphirhynchus albus have been ongoing since its listing in 1990. Its congener, the Shovelnose Sturgeon S. platorynchus, has also recently been listed as threatened where it overlaps with Pallid Sturgeon. The status of both species in the Mississippi River is unknown and so are habitat enhancement priorities that would benefit their recovery. Using field data collected from 2002 through 2005, we (1) estimated the adult population size of both species using mark–recapture methods and (2) quantified habitat use of these sturgeons with multiple gears to elucidate habitat enhancement priorities in the middle Mississippi River—an important fluvial corridor that connects the upper Mississippi River and Missouri River basins with the lower Mississippi River basin. Population size was estimated to be 1,516 (95% CI = 710–3,463) Pallid Sturgeon (five individuals per river kilometer [rkm]) and 82,336 (95% CI = 59,438–114,585) Shovelnose Sturgeon (266 individuals/rkm). Our population estimate showed a low relative abundance of Pallid Sturgeon in this corridor. However, the population estimate suggests Pallid Sturgeon abundance has increased since its listing in 1990. Shovelnose Sturgeon were more abundant than Pallid Sturgeon, but whether the Shovelnose Sturgeon population is increasing, decreasing, or stable remains unknown. Among 10 habitat types, both species were most frequent at the downstream ends of alluvial islands. Pallid and Shovelnose sturgeons were restricted to flow rates < 1.0 m/s, and their abundance was greatest in depths ranging from 4.5 to 14 m. We suggest alluvial island enhancement may facilitate sturgeon recovery in the middle Mississippi River.

Received February 24, 2014; accepted December 2, 2015
Male professional tennis players maintain constant serve speed and accuracy over long matches on grass courts
Authors: Maquirriain Javier , Baglione Roberto , Cardey Marcelo
Published: March 2016

The potential effect of fatigue on stroke production in tennis players is still controversial. The aim of this study was to analyse the tennis serve speed and accuracy in prolonged male professional matches played on grass courts. We analysed tennis serve statistics from five‐set Wimbledon matches (n = 15; 30 players). Results showed that match duration averaged 208.3 ± 28.3 min. The overall serve speed was 177.0 ± 10.2 km/h in the first set and 176.1 ± 11.7 km/h in the fifth set (p = .34). The difference of all accuracy values of first set serves was not significantly different from those of the fifth set: percentage of valid first serves, 63.1 ± 11.1% vs. 62.3 ± 11.8%, respectively (p = .78); percentage of “aces”, 11.2 ± 9.1% vs. 10.0 ± 8.9%, respectively (p = .39); percentage of “winners”, 2.6 ± 7.6% vs. 1.2 ± 2.2%, respectively (p = .36); percentage of “double faults”, 2.8 ± 3.0% vs. 2.8 ± 3.4% (p = .97). In conclusion, tennis players were able to maintain constant serve speed and accuracy over five‐set matches played on grass courts. Professional tennis players are capable of overcoming fatigue and/or make movement adjustments to effectively perform complex technical strokes like the serve throughout matches played on grass courts lasting more than 3 h in average.
Transcription factor ATF4 directs basal and stress-induced gene expression in the unfolded protein response and cholesterol metabolism in the liver
Authors: Fusakio Michael E. , Willy Jeffrey A. , Wang Yongping , Mirek Emily T. , Al Baghdadi Rana J. T. , Adams Christopher M. , Anthony Tracy G. , Wek Ronald C.
Published: March 2016

Disturbances in protein folding and membrane compositions in the endoplasmic reticulum (ER) elicit the unfolded protein response (UPR). Each of three UPR sensory proteins—PERK (PEK/EIF2AK3), IRE1, and ATF6—is activated by ER stress. PERK phosphorylation of eIF2 represses global protein synthesis, lowering influx of nascent polypeptides into the stressed ER, coincident with preferential translation of ATF4 (CREB2). In cultured cells, ATF4 induces transcriptional expression of genes directed by the PERK arm of the UPR, including genes involved in amino acid metabolism, resistance to oxidative stress, and the proapoptotic transcription factor CHOP (GADD153/DDIT3). In this study, we characterize whole-body and tissue-specific ATF4-knockout mice and show in liver exposed to ER stress that ATF4 is not required for CHOP expression, but instead ATF6 is a primary inducer. RNA-Seq analysis indicates that ATF4 is responsible for a small portion of the PERK-dependent UPR genes and reveals a requirement for expression of ATF4 for expression of genes involved in oxidative stress response basally and cholesterol metabolism both basally and under stress. Consistent with this pattern of gene expression, loss of ATF4 resulted in enhanced oxidative damage, and increased free cholesterol in liver under stress accompanied by lowered cholesterol in sera.
Relationship Between Carotid Atherosclerosis and Pulse Pressure with Renal Hemodynamics in Hypertensive Patients
Authors: Geraci Giulio , Mulè Giuseppe , Costanza Giuseppa , Mogavero Manuela , Geraci Calogero , Cottone Santina
Published: March 2016

BACKGROUND

Structural atherosclerotic damage, arterial stiffness, pulse pressure (PP), and renal hemodynamics may interact and influence each other. Renal resistance index (RRI) appears as a good indicator of systemic vascular changes. The aim of our study was to assess the independent relationships of carotid intima-media thickness (cIMT), aortic pulse wave velocity (aPWV), and peripheral PP with RRI in hypertensives with various degrees of renal function.

METHODS

We enrolled 463 hypertensive patients (30–70 years) with normal renal function (group 0; n = 280) and with chronic kidney disease (groups I–V; n = 183). All subjects underwent ultrasonographic examination of intrarenal and carotid vasculature, as well as a 24-h ambulatory blood pressure monitoring.

RESULTS

A statistically significant difference in RRI, cIMT, aPWV, and clinic PP was observed in the different 6 groups (all P < 0.001), even after adjustment for age. RRI correlated with cIMT ( r = 0.460, P < 0.001), aPWV ( r = 0.386, P < 0.001), clinic PP ( r = 0.279, P < 0.001), and 24-h PP ( r = 0.229, P < 0.001) in the entire study population. These correlations were similar in subjects with and without renal dysfunction. In the overall study population, the association between RRI, cIMT, and clinic PP remained statistically significant even after adjustment for various confounding factors, whereas the relationship between RRI and aPWV was lost in multivariate analysis.

CONCLUSIONS

cIMT and clinic PP rather than directly aPWV are associated with intrarenal hemodynamics. Our results confirm that in hypertensives RRI not only detects derangement of intrarenal circulation but may also be considered as a sensor of systemic vascular changes, independently of level of renal function.
Cumulative Hypoxemia During Sleep Predicts Vascular Endothelial Dysfunction in Patients With Sleep-Disordered Breathing
Authors: Sawatari Hiroyuki , Chishaki Akiko , Nishizaka Mari , Tokunou Tomotake , Adachi Sonomi , Yoshimura Chikara , Ohkusa Tomoko , Ando Shin-ichi
Published: March 2016

BACKGROUND

Sleep-disordered breathing (SDB) is associated with repeated intermittent hypoxemia, and it is known as one of the risk factors for cardiovascular diseases. Previous studies assessing the effects of frequency and depth of hypoxemia on cardiovascular diseases have shown conflicting results. The aim of the current study was to clarify what SDB-related parameters most predict endothelial dysfunction to better understand the pathogenesis of endothelial dysfunction in patients with SDB.

METHODS

We conducted polysomnography (PSG) and measured flow-mediated vasodilation response (%FMD) in 50 outpatients suspected of SDB. Evaluated indices included: apnea-hypopnea index (AHI), 3% oxygen desaturation index (3%ODI), averaged arterial oxygen saturation (averaged SpO 2 ), lowest arterial oxygen saturation (lowest SpO 2 ), ratio of arterial oxygen saturation <90% (<SpO 2 90%), and averaged time desaturation summation index (TDS: [100%-averaged SpO 2 ] × total sleep time).

RESULTS

Significant differences were observed only in the TDS between the first and third ( P = 0.03) and between the first and forth ( P = 0.04) quartile groups, stratified by %FMD. The %FMD showed a significant relationship with TDS ( β = −0.47, P = 0.001), even after adjusting for confounding factors ( β = −0.33, P = 0.02). In contrast, AHI, 3%ODI, averaged SpO 2 , lowest SpO 2 , and <SpO 2 90% showed no significant relationships.

CONCLUSIONS

This study shows the validity of TDS in predicting endothelial damage in patients with SDB. Cumulative hypoxemia, rather than the frequency of hypoxemic events presented as AHI, may be a greater contributing factor in causing endothelial dysfunction. A simple index like TDS may be a useful and novel indicator of the influence of SDB on the vasculature.
Phasing for medical sequencing using rare variants and large haplotype reference panels
Authors: Sharp Kevin , Kretzschmar Warren , Delaneau Olivier , Marchini Jonathan
Published: March 2016

Motivation: There is growing recognition that estimating haplotypes from high coverage sequencing of single samples in clinical settings is an important problem. At the same time very large datasets consisting of tens and hundreds of thousands of high-coverage sequenced samples will soon be available. We describe a method that takes advantage of these huge human genetic variation resources and rare variant sharing patterns to estimate haplotypes on single sequenced samples. Sharing rare variants between two individuals is more likely to arise from a recent common ancestor and, hence, also more likely to indicate similar shared haplotypes over a substantial flanking region of sequence.

Results: Our method exploits this idea to select a small set of highly informative copying states within a Hidden Markov Model (HMM) phasing algorithm. Using rare variants in this way allows us to avoid iterative MCMC methods to infer haplotypes. Compared to other approaches that do not explicitly use rare variants we obtain significant gains in phasing accuracy, less variation over phasing runs and improvements in speed. For example, using a reference panel of 7420 haplotypes from the UK10K project, we are able to reduce switch error rates by up to 50% when phasing samples sequenced at high-coverage. In addition, a single step rephasing of the UK10K panel, using rare variant information, has a downstream impact on phasing performance. These results represent a proof of concept that rare variant sharing patterns can be utilized to phase large high-coverage sequencing studies such as the 100 000 Genomes Project dataset.

Availability and implementation: A webserver that includes an implementation of this new method and allows phasing of high-coverage clinical samples is available at https://phasingserver.stats.ox.ac.uk/.

Contact:  marchini@stats.ox.ac.uk

Supplementary information:  Supplementary data are available at Bioinformatics online.
Rapid genotype refinement for whole-genome sequencing data using multi-variate normal distributions
Authors: Arthur Rudy , O’Connell Jared , Schulz-Trieglaff Ole , Cox Anthony J.
Published: March 2016

Motivation: Whole-genome low-coverage sequencing has been combined with linkage-disequilibrium (LD)-based genotype refinement to accurately and cost-effectively infer genotypes in large cohorts of individuals. Most genotype refinement methods are based on hidden Markov models, which are accurate but computationally expensive. We introduce an algorithm that models LD using a simple multivariate Gaussian distribution. The key feature of our algorithm is its speed.

Results: Our method is hundreds of times faster than other methods on the same data set and its scaling behaviour is linear in the number of samples. We demonstrate the performance of the method on both low- and high-coverage samples.

Availability and implementation: The source code is available at https://github.com/illumina/marvin

Contact:  rarthur@illumina.com

Supplementary information:  Supplementary data are available at Bioinformatics online.
Ecology, distribution, and predictive occurrence modeling of Palmer’s chipmunk (Tamias palmeri): a high-elevation small mammal endemic to the Spring Mountains in southern Nevada, USA
Authors: Lowrey Christopher , Longshore Kathleen , Riddle Brett , Mantooth Stacy
Published: March 2016

Although montane sky islands surrounded by desert scrub and shrub steppe comprise a large part of the biological diversity of the Basin and Range Province of southwestern North America, comprehensive ecological and population demographic studies for high-elevation small mammals within these areas are rare. Here, we examine the ecology and population parameters of the Palmer’s chipmunk (Tamias palmeri) in the Spring Mountains of southern Nevada, and present a predictive GIS-based distribution and probability of occurrence model at both home range and geographic spatial scales. Logistic regression analyses and Akaike Information Criterion model selection found variables of forest type, slope, and distance to water sources as predictive of chipmunk occurrence at the geographic scale. At the home range scale, increasing population density, decreasing overstory canopy cover, and decreasing understory canopy cover contributed to increased survival rates.
Obstacles to activity pacing: assessment, relationship to activity and functioning
Authors: Cane Douglas , McCarthy Mary , Mazmanian Dwight
Published: March 2016

Activity pacing is frequently included among the strategies provided to individuals with chronic pain to manage pain and improve functioning. Individuals with chronic pain may, however, limit their use of activity pacing because they perceive significant obstacles to its use. This study describes the development of a measure to assess obstacles to activity pacing and examines the relationship of this measure to activity patterns and functioning. A sample of 637 individuals with chronic pain completed items describing potential obstacles to activity pacing as part of their pretreatment assessment. Item analyses were used to construct a 14-item measure of obstacles to activity pacing. A subset of these individuals completed the measure again after completion of a group treatment program. The resulting measure demonstrated excellent internal consistency and was minimally affected by social desirability. Correlations with measures of activity and psychosocial functioning provided initial construct validity for the measure. Sex differences were found with women initially identifying more obstacles to activity pacing. Fewer obstacles were identified by both men and women after treatment, and these changes were related to modest changes in activity patterns and functioning. The present results identify a number of obstacles that may limit the use of activity pacing by individuals with chronic pain. Treatment may result in a decrease in the number of obstacles identified, and this change is related to changes in the individual's activity pattern and psychosocial functioning.
(S)-lacosamide inhibition of CRMP2 phosphorylation reduces postoperative and neuropathic pain behaviors through distinct classes of sensory neurons identified by constellation pharmacology
Authors: Moutal Aubin , Chew Lindsey A. , Yang Xiaofang , Wang Yue , Yeon Seul Ki , Telemi Edwin , Meroueh Seeneen , Park Ki Duk , Shrinivasan Raghuraman , Gilbraith Kerry B. , Qu Chaoling , Xie Jennifer Y. , Patwardhan Amol , Vanderah Todd W. , Khanna May , Porreca Frank , Khanna Rajesh
Published: March 2016

Chronic pain affects the life of millions of people. Current treatments have deleterious side effects. We have advanced a strategy for targeting protein interactions which regulate the N-type voltage-gated calcium (CaV2.2) channel as an alternative to direct channel block. Peptides uncoupling CaV2.2 interactions with the axonal collapsin response mediator protein 2 (CRMP2) were antinociceptive without effects on memory, depression, and reward/addiction. A search for small molecules that could recapitulate uncoupling of the CaV2.2–CRMP2 interaction identified (S)-lacosamide [(S)-LCM], the inactive enantiomer of the Food and Drug Administration–approved antiepileptic drug (R)-lacosamide [(R)-LCM, Vimpat]. We show that (S)-LCM, but not (R)-LCM, inhibits CRMP2 phosphorylation by cyclin dependent kinase 5, a step necessary for driving CaV2.2 activity, in sensory neurons. (S)-lacosamide inhibited depolarization-induced Ca2+ influx with a low micromolar IC50. Voltage-clamp electrophysiology experiments demonstrated a commensurate reduction in Ca2+ currents in sensory neurons after an acute application of (S)-LCM. Using constellation pharmacology, a recently described high content phenotypic screening platform for functional fingerprinting of neurons that uses subtype-selective pharmacological agents to elucidate cell-specific combinations (constellations) of key signaling proteins that define specific cell types, we investigated if (S)-LCM preferentially acts on certain types of neurons. (S)-lacosamide decreased the dorsal root ganglion neurons responding to mustard oil, and increased the number of cells responding to menthol. Finally, (S)-LCM reversed thermal hypersensitivity and mechanical allodynia in a model of postoperative pain, and 2 models of neuropathic pain. Thus, using (S)-LCM to inhibit CRMP2 phosphorylation is a novel and efficient strategy to treat pain, which works by targeting specific sensory neuron populations.
Effectiveness of an Adaptive Quizzing System as an Institutional-Wide Strategy to Improve Student Learning and Retention
Authors: Simon-Campbell E';Loria , Phelan Julia
Published: March 2016

Exploring ways to help students achieve success in nursing programs is critical to increase retention and the number of nurse graduates. This study examined the impact of an adaptive quizzing system implemented as a strategy to support student persistence and performance measured by use, grades, and graduation. Results indicated that use of the system increased course content mastery and predicted final course grades. Retention and program completion rates were also positively influenced.
Synthesis and characterization of two novel bimetallic macrocyclic complexes generated from 1,2,4-triazole-containing semi-rigid ligands andM(NO3)2units (M= Ni and Zn)
Authors: Wu Xiang-Wen , Yin Shi , Wu Wan-Fu , Ma Jian-Ping
Published: March 2016

Bimetallic macrocyclic complexes have attracted the attention of chemists and various organic ligands have been used as molecular building blocks, but supramolecular complexes based on semi-rigid organic ligands containing 1,2,4-triazole have remained rare until recently. It is easier to obtain novel topologies by making use of asymmetric semi-rigid ligands in the self-assembly process than by making use of rigid ligands. A new semi-rigid ligand, 3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine (L), has been synthesized and used to generate two novel bimetallic macrocycle complexes, namely bis{μ-3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine}bis[(methanol-κO)(nitrato-κ2O,O′)nickel(II)] dinitrate, [Ni2(NO3)2(C17H14N6S)2(CH3OH)2](NO3)2, (I), and bis{μ-3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine}bis[(methanol-κO)(nitrato-κ2O,O′)zinc(II)] dinitrate, [Zn2(NO3)2(C17H14N6S)2(CH3OH)2](NO3)2, (II), by solution reactions with the inorganic saltsM(NO3)2(M= Ni and Zn, respectively) in mixed solvents. In (I), two NiIIcations with the same coordination environment are linked byLligands through Ni—N bonds to form a bimetallic ring. Compound (I) is extended into a two-dimensional network in the crystallographicacplaneviaN—H...O, O—H...N and O—H...O hydrogen bonds, and neighbouring two-dimensional planes are parallel and form a three-dimensional structureviaπ–π stacking. Compound (II) contains two bimetallic rings with the same coordination environment of the ZnIIcations. The ZnIIcations are bridged byLligands through Zn—N bonds to form the bimetallic rings. One type of bimetallic ring constructs a one-dimensional nanotubeviaO—H...O and N—H...O hydrogen bonds along the crystallographicadirection, and the other constructs zero-dimensional molecular cagesviaO—H...O and N—H...O hydrogen bonds. They are interlinked into a two-dimensional network in theacplane through extensive N—H...O hydrogen bonds, and a three-dimensional supramolecular architecture is formedviaπ–π interactions between the centroids of the benzene rings of the quinoline ring systems.
Redetermination of the crystal structure of boron subphthalocyanine chloride (Cl-BsubPc) enabled by slow train sublimation
Authors: Virdo Jessica D. , Lough Alan J. , Bender Timothy P.
Published: March 2016

The crystal structure of boron subphthalocyanine chloride [systematic name: chlorido(subphthalocyaninato)boron], C24H12BClN6, a material of widespread interest in organic electronic device applications, has been redetermined with a higher precision using large single crystals obtainedviaslow train sublimation. Details are given for the construction and operation of the train sublimation system, which has been designed to reproducibly yield single crystals suitable for diffraction experiments in a manner which approximates the vacuum deposition conditions commonly used to fabricate organic electronic devices. Diffraction experiments were conducted using two crystal samples and four temperatures (90, 123, 147 and 295 K), enabling a discussion of changes in the unit cell and intermolecular interactions with respect to temperature and in comparison to two previously published structures of Cl-BsubPc. The redetermined structure confirms the original structure published 41 years ago [Meller & Ossko (1972).Monatsh. Chem.103, 150–155], with significantly improved precision for the geometric parameters. Analysis of the crystal structure revealed three intersecting ribbon motifs formed through a combination of π–π and halogen–π (specifically B—Cl...π) interactions. H atoms were refined independently in order to facilitate a thorough discussion of these intermolecular interactions using Hirshfeld surface analysis.
Comparison of the crystal structures of the potent anticancer and anti-angiogenic agent regorafenib and its monohydrate
Authors: Sun Meng-Ying , Wu Su-Xiang , Zhou Xin-Bo , Gu Jian-Ming , Hu Xiu-Rong
Published: March 2016

Regorafenib {systematic name: 4-[4-({[4-chloro-3-(trifluoromethy)phenyl]carbamoyl}amino)-3-fluorophenoxy]-1-methylpyridine-2-carboxamide}, C21H15ClF4N4O3, is a potent anticancer and anti-angiogenic agent that possesses various activities on the VEGFR, PDGFR, raf and/or flt-3 kinase signaling molecules. The compound has been crystallized as polymorphic form I and as the monohydrate, C21H15ClF4N4O3·H2O. The regorafenib molecule consists of biarylurea and pyridine-2-carboxamide units linked by an ether group. A comparison of both forms shows that they differ in the relative orientation of the biarylurea and pyridine-2-carboxamide units, due to different rotations around the ether group, as measured by the C—O—C bond angles [119.5 (3)° in regorafenib and 116.10 (15)° in the monohydrate]. Meanwhile, the conformational differences are reflected in different hydrogen-bond networks. Polymorphic form I contains two intermolecular N—H...O hydrogen bonds, which link the regorafenib molecules into an infinite molecular chain along thebaxis. In the monohydrate, the presence of the solvent water molecule results in more abundant hydrogen bonds. The water molecules act as donors and acceptors, forming N—H...O and O—H...O hydrogen-bond interactions. Thus,R42(28) ring motifs are formed, which are fused to form continuous spiral ring motifs along theaaxis. The (trifluoromethyl)phenyl rings protrude on the outside of these motifs and interdigitate with those of adjacent ring motifs, thereby forming columns populated by halogen atoms.
Bis{bis(azido-κN)bis[bis(pyridin-2-yl-κN)amine]cobalt(III)} sulfate dihydrate
Authors: Setifi Fatima , Knaust Jacqueline M. , Setifi Zouaoui , Touzani Rachid
Published: March 2016

The search for new molecular materials with interesting magnetic properties, using the pseudohalide azide ion and di-2-pyridylamine (dpa, C10H9N3) as a chelating ligand, led to the synthesis and structure determination of the title compound, [Co(N3)2(dpa)2]2SO4·2H2O. The crystal structure comprises discrete [Co(dpa)2(N3)2]+cations, sulfate anions, as well as H2O solvent molecules. The CoIIIcations display a slightly distorted octahedral coordination sphere defined by two N atoms from azide anions and four N atoms from the pyridyl rings of two dpa ligands. In the crystal, extensive C—H...O, N—H...O, and O—H...O interactions result in supramolecular sheets that lie parallel to theabplane. The sheets are further linked through O—H...N interactions between the water molecules of one sheet and azide anions of another sheet, forming a supramolecular framework.
Crystal structures of the two salts 2-methyl-1H-imidazol-3-ium nitrate–2-methyl-1H-imidazole (1/1) and 2-methyl-1H-imidazol-3-ium nitrate
Authors: Diop Mouhamadou Birame , Diop Libasse , Maris Thierry
Published: March 2016

The title salts, C4H7N2+·NO3−·C4H6N2, (I), and C4H7N2+·NO3−, (II), were obtained from solutions containing 2-methylimidazole and nitric acid in different concentrations. In the crystal structure of salt (I), one of the –NH H atoms of the imidazole ring shows half-occupancy, hence only every second molecule is in its cationic form. The nitrate anion in this structure lies on a twofold rotation axis. The neutral 2-methylimidazole molecule and the 2-methyl-1H-imidazol-3-ium cation interact through N—H...N hydrogen bonds to form [(C4H6N2)...(C4H7N2)+] pairs. These pairs are linked with two nitrate anions on both sides through bifurcated N—H...(O,O) hydrogen bonds into chains running parallel to [001]. In the crystal structure of salt (II), the C4H7N2+cation and the NO3−anion are both located on a mirror plane, leading to a statistical disorder of the methyl H atoms. The cations and anions again interact through bifurcated N—H...(O,O) hydrogen bonds, giving rise to the formation of chains consisting of alternating anions and cations parallel to [100].
2,5-Dimethoxy-3,4,6-trimethylbenzaldehyde
Authors: Wickramasinhage Ravindra , McAdam C. John , Simpson Jim
Published: March 2016

In the molecule of the title compound, C12H16O3, the methyl and aldehyde substituents are disordered over four inversion-related C atoms on the benzene ring with an occupancy ratio of 0.75:0.25. The crystal structure features weak C—H...O hydrogen bonds and C—H...π contacts between a methoxy/methyl group and the benzene ring.
Diaminomesitylene
Authors: Brihi Ouarda , Hamdouni Noudjoud , Boulcina Raouf , Medjani Meriem , Meinnel Jean , Boudjada Ali
Published: March 2016

The title compound, C9H14N2(systematic name: 2,4,6-trimethylbenzene-1,3-diamine), is almost planar (r.m.s. deviation = 0.025 Å). In the crystal, molecules are linkedviaN—H...N hydrogen bonds, forming zigzag chains along theb-axis direction. Only one of the four N-bonded H atoms forms a hydrogen bond, perhaps due to steric crowding. The chains are linked by C—H...π interactions, forming sheets lying parallel to thebcplane
(tert-Butyl isocyanide-κC)trichloridogallium(III)
Authors: Bourque Jeremy L. , Tashkandi Nada Y. , Baines Kim M.
Published: March 2016

The crystal structure of (tert-butyl isocyanide-κC)trichloridogallium(III), [GaCl3(C5H9N)], features the first reported isocyanide–gallium trihalide complex. The Ga—C—N—C fragment is essentially linear. The methyl fragments of thetert-butyl group are eclipsed with the chloride ligands on the Ga atom. The molecule does not, however, exhibit threefold crystallographic symmetry, as it crystallizes within theP21/cspace group.
Cultural distance, innovation and export performance
Authors: Azar Goudarz , Drogendijk Rian
Published: March 2016

Purpose

This paper aims to examine the relationship between cultural distance (both perceived and objective), innovation and firm export performance.

Design/methodology/approach

Hypotheses were tested here by structural equation modeling using data from 186 export ventures into 23 international markets by Swedish companies.

Findings

The results indicate that managers’ perceptions of substantial cultural differences as well as objective cultural differences (gauged using Hofstede’s (1980, 2001) scores for dimensions of national culture) and subsequent environmental uncertainty when expanding into culturally distant markets triggers strategies for interacting and integrating with the market environment. These include producing and adopting innovations to processes and products and to organizational strategy, structure and administrative procedures to cope with the new environment and overcome uncertainties. These innovations and the associated competitive advantages improve firm export performance.

Originality/value

Despite much research into the relationship between firm internationalization and innovation, little attention has been paid to the effect of the characteristics of the foreign markets (specifically cultural differences) on firm innovation strategies. Moreover, much research has been devoted to the effect of innovation on firm export performance, but such research has mainly focused on one type of innovation, i.e. technological innovation, while the influence of organizational innovation on firm export performance has been basically ignored. The present study validates the explanatory of cultural distance (both perceived and objective) in relation to innovation strategies (technological and organizational) and export performance.
Increase in the demand for private higher education: unmasking the “paradox”
Authors: Garwe Evelyn Chiyevo
Published: March 2016

Purpose

– It is considered a mystery by many people that, despite charging significantly higher fees when compared to public institutions, research has shown an increase in the demand and enrolments at private higher education institutions. The purpose of this paper is to investigate the critical factors considered by students when deciding to make private higher education institutions their institution of choice.

Design/methodology/approach

– The study uses a case study approach and draws data from all the six private higher education institutions in Zimbabwe. Self-administered questionnaires were given to students representing at least 5 per cent of the student enrolment and representing all gender, study disciplines and levels of study from each university.

Findings

– Irrespective of gender, six main factors influencing student choice were identified to be, in order of priority: access and opportunity; promotional information and marketing; reference or influence by others; quality of teaching and learning; fees and cost structure, and finally academic reputation and recognition.

Research limitations/implications

– The research was focused on a case study of Zimbabwe.

Practical implications

– The study has implications on the way private higher education institutions market, manage and sustain the quality of educational provision. The study therefore provides private institutions with useful and practical insights on what students want in their institution of choice. This will assist these institutions in strategising in order to sustain or gain competitive advantage and to maximise on the increasing demand for private education. Implications to government and public institutions are also given.

Social implications

– The study recognises the critical role played by private universities in improving access and recommends African Governments who face financial and resource constraints to fund and expand public universities to encourage private higher education as a meaningful and viable way to improve access and provide higher education opportunities to potential students.

Originality/value

– The study contributes to the current dearth of literature on factors influencing student choice to study with private institutions.
Understanding performance management in schools: a dialectical approach
Authors: Page Damien
Published: March 2016

Purpose

– The purpose of this paper is to provide a dialectical framework for the examination of performance management in schools.

Design/methodology/approach

– The paper is based upon a qualitative study of ten headteachers that involved in-depth semi-structured interviews.

Findings

– The findings identified four dialectical tensions that underpin performance management in schools: the responsibility to teachers and the responsibility to pupils; external accountability and professional autonomy; discipline of teachers and support of teachers; fixed processes and improvisational practices.

Research limitations/implications

– This paper provides a means of examining the performance management of teachers from an alternative perspective, one that embraces tensions and contradictions and gives headteachers a richer understanding of how teachers are evaluated and judged.

Originality/value

– This paper moves beyond the traditional perspective of performance management in schools as a means of subjugation and control and offers an original dialectical framework within which to examine the phenomenon.
Mothers’ non-standard working schedules and family time
Authors: Murtorinne-Lahtinen Minna , Moilanen Sanna , Tammelin Mia , Rönkä Anna , Laakso Marja-Leena
Published: March 2016

Purpose

– The purpose of this paper is to investigate Finnish working mothers’ experiences of the effects of non-standard working schedules (NSWS) on family time in two family forms, coupled and lone-parent families. Furthermore the aim is to find out what meanings mothers with NSWS attached to family time paying particular attention to the circumstances in which mothers experienced NSWS positively.

Design/methodology/approach

– Thematic analysis of 20 semi-structured interviews was used to investigate mothers’ experiences of the effects of NSWS on family time.

Findings

– The key factor generating positive experiences was the ability to maintain regularity and togetherness, which was enhanced by specific features of work, such as autonomy and regularity, and successful child care arrangements. Also important were the values mothers associated with family time. The results highlighted the more problematic situation of lone-parent families.

Research limitations/implications

– The main limitation of this study was the small sample size.

Practical implications

– The findings show how the parents of small children benefit from the regularity and flexibility in their working hours. Owing to irregular and varying working times, flexible around-the-clock childcare is needed. In Finland, an important question is how to organize the care of small school-aged children. Lone mothers, especially, may need services to help with domestic chores and childcare.

Social implications

– A non-resident parent can also be an important source of childcare. Therefore policymakers should take into account family type, including consideration of the rights to childcare of non-resident parents.

Originality/value

– This study adds to the literature by explaining more in depth, through the richness of qualitative data, the circumstances in which mothers experience NSWS positively.