bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐order DG solvers for underresolved turbulent incompressible flows: A comparison of L2 and H(div) methods
Authors: Fehn Niklas , Kronbichler Martin , Lehrenfeld Christoph , Lube Gert , Schroeder Philipp W.
Published: August 2019

The accurate numerical simulation of turbulent incompressible flows is a challenging topic in computational fluid dynamics. For discretisation methods to be robust in the underresolved regime, mass conservation and energy stability are key ingredients to obtain robust and accurate discretisations. Recently, two approaches have been proposed in the context of high‐order discontinuous Galerkin (DG) discretisations that address these aspects differently. On the one hand, standard L2‐based DG discretisations enforce mass conservation and energy stability weakly by the use of additional stabilisation terms. On the other hand, pointwise divergence‐free H(div)‐conforming approaches ensure exact mass conservation and energy stability by the use of tailored finite element function spaces. This work raises the question whether and to which extent these two approaches are equivalent when applied to underresolved turbulent flows. This comparative study highlights similarities and differences of these two approaches. The numerical results emphasise that both discretisation strategies are promising for underresolved simulations of turbulent flows due to their inherent dissipation mechanisms.
A phase II study to assess the safety and efficacy of the dual mTORC1/2 inhibitor vistusertib in relapsed, refractory DLBCL
Authors: Eyre Toby A. , Hildyard Catherine , Hamblin Angela , Ali Ayesha S. , Houlton Aimee , Hopkins Louise , Royston Daniel , Linton Kim M. , Pettitt Andrew , Rule Simon , Cwynarski Kate , Barrington Sally F. , Warbey Victoria , Wrench David , Barrans Sharon , Hirst Caroline S. , Panchal Anesh , Roudier Martine P. , Harrington Elizabeth A. , Davies Andrew , Collins Graham P.
Published: August 2019

Patients with relapsed or refractory diffuse large B‐cell lymphoma (DLBCL) who are unfit for or relapsed postautologous stem‐cell transplantation have poor outcomes. Historically, mTORC1 inhibitors have produced responses in approximately 30% of patients in this setting. mTORC1 inhibitor efficacy may be limited by resistance mechanisms including AKT activation by mTORC2. To date, dual mTORC1/2 inhibitors targeting both the TORC1 and TORC2 complexes have not been investigated in DLBCL. This phase II trial investigated the oral dual mTORC1/2 inhibitor vistusertib in an intermittent dosing schedule of 125 mg b.d. for 2 days per week. Thirty patients received vistusertib and six received vistusertib‐rituximab for up to six cycles (28‐day cycles). Two partial responses were achieved on monotherapy. Durations of response were 57 and 62 days, respectively, for these patients. 19% had stable disease within six cycles. In the monotherapy arm, the median progression‐free survival was1.69 (95% confidence interval [CI] 1.61‐2.14) months and median overall survival was 6.58 (95% CI 3.81‐not reached) months, respectively. The median duration of response or stable disease across the trial duration was 153 days (95% CI 112‐not reached). Tumour responses according to positron emission tomography/computed tomography versus computed tomography were concordant. There were no differences noted in tumour volume response according to cell of origin by either gene expression profiling or immunohistochemistry. Vistusertib ± rituximab was well tolerated; across 36 patients 86% of adverse events were grade (G) 1‐2. Common vistusertib‐related adverse events were similar to those described with mTORC1 inhibitors: nausea (47% G1‐2), diarrhoea (27% G1‐2, 6% G3), fatigue (30% G1‐2, 3% G3), mucositis (25% G1‐2, 6% G3), vomiting (17% G1‐2), and dyspepsia (14% G1‐2). Dual mTORC1/2 inhibitors do not clearly confer an advantage over mTORC1 inhibitors in relapsed or refractory DLBCL. Potential resistance mechanisms are discussed within.
Acetaminophen‐induced hepatocyte injury: C2‐ceramide and oltipraz intervention, hepatocyte nuclear factor 1 and glutathione S‐transferase A1 changes
Authors: Chang Yicong , Wang Feng , Yang Yang , Zhang Yuanyuan , Muhammad Ishfaq , Li Rui , Li Changwen , Li Ying , Shi Chenxi , Ma Xin , Hao Beili , Liu Fangping
Published: August 2019

Acetaminophen (APAP) is an antipyretic and analgesic, which is commonly associated with drug‐induced hepatic injury. C2‐ceramide plays a key role in mediating cell life activities, and oltipraz was extensively studied as a cancer chemopreventive agent. Glutathione S‐transferase A1 (GSTA1) acts as a vital liver detoxification enzyme. Hepatocyte nuclear factor 1 (HNF‐1) regulates various cellular signaling pathways. In this study, we investigated the effects of C2‐ceramide and oltipraz on APAP‐induced hepatocyte injury and the changes of HNF‐1 and GSTA1. Results showed that C2‐ceramide (6 μmol/L) exacerbated APAP‐induced hepatocyte injury and caused a significant decrease (P < .01) in HNF‐1 and GSTA1 expressions. Meanwhile, GSTA1 content in supernatant was significantly increased (P < .01). In contrast, oltipraz (8 μmol/L) reduced the injury and significantly elevated (P < .01) HNF‐1 and GSTA1 expressions while GSTA1 content in supernatant was significantly decreased (P < .01). In conclusion, these findings revealed that C2‐ceramide inhibited HNF‐1 and GSTA1 expression and exacerbated hepatocyte injury, while oltipraz treatment results in the reduction of hepatocyte injury, and promoted HNF‐1 and GSTA1 expression. Additionally, the changes in HNF‐1 and GSTA1 were related to APAP‐induced hepatocyte injury. These results were useful to investigate the mechanism of an antipyretic and analgesic drug combination.
Effect of metformin on myotube BCAA catabolism
Authors: Rivera Madison E. , Lyon Emily S. , Vaughan Roger A.
Published: August 2019

Metformin has antihyperglycemic properties and is a commonly prescribed drug for type II diabetes mellitus. Metformin functions in part by activating 5′‐AMP‐activated protein kinase, reducing hepatic gluconeogenesis and blood glucose. Metformin also upregulates peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α). Several population studies have shown levels of circulating branched‐chain amino acids (BCAA) positively correlate with insulin resistance. Because BCAA catabolic enzyme content is regulated by PGC‐1α, we hypothesized metformin may alter BCAA catabolism. Therefore, the purpose of this work was to investigate the effect of metformin at varying concentrations on myotube metabolism and related gene and protein expression. C2C12 myotubes were treated with metformin at 30 uM (physiological) or 2 mM (supraphysiological) for up to 24 hours. Metabolic gene expression was measured via quantitative real time polymerase chain reaction, protein expression was measured using Western blot, and mitochondrial and glycolytic metabolism were measured via oxygen consumption and extracellular acidification rate, respectively. Supraphysiological metformin upregulated PGC‐1α mRNA expression along with related downstream targets, yet the reduced expression of electron transport chain components as well as basal and peak cell metabolism. Supraphysiological metformin also suppressed branched‐chain aminotransferase 2 (BCAT2) and branched‐chain‐alpha‐keto acid dehydrogenase E1a (BCKDHa) mRNA expression as well as BCAT2 protein expression and BCKDHa activity, which was accompanied by decreased Kruppel‐like factor 15 protein expression. Physiological levels of metformin suppressed BCKDHa and cytochrome c oxidase mRNA expression at early time points (4‐12 hours) but had no effect on any other outcomes. Together these data suggest metformin may suppress BCAA catabolic enzyme expression or activity, possibly reducing levels of circulating gluconeogenic substrates.
Emotion regulation strategies in mania risk: A systematic review
Authors: McGrogan Claire L. , Dodd Alyson L. , Smith Michael A.
Published: August 2019

Objectives

Difficulties in emotion regulation may contribute to the development of mania. This review aimed to assess how emotion regulation strategies reported by individuals at risk of mania compare with clinical and nonclinical controls.

Methods

Search terms relating to mania risk and emotion regulation were entered into three databases. Sixteen studies were included.

Results

Mania risk was typically associated with overall endorsement of emotion regulation strategies, particularly dampening, and positive and negative rumination.

Conclusions

Findings were limited by overall lack of evidence for individual strategies, lack of consideration of key mediating factors and reliance upon self‐report designs.
Echocardiography and electrocardiography reveal differences in cardiac hemodynamics, electrical characteristics, and thermal sensitivity between northern pike, rainbow trout, and white sturgeon
Authors: Ma Kathleen G. L. , Gamperl A. Kurt , Syme Douglas A. , Weber Lynn P. , Rodnick Kenneth J.
Published: August 2019

Doppler and B‐mode ultrasonography and electrocardiography (ECG) were used to determine cardiac hemodynamics and electrical characteristics in 12°C‐acclimated and metomidate‐anesthetized northern pike, rainbow trout and white sturgeon (7–9 per species) at 12°C and 20°C, and at a comparable heart rate (fH, ~60 beats/min). Despite similar relative ventricle masses and cardiac output (Q), interspecific differences were observed at 12°C in fH, ventricular filling and ejection, stroke volume, the duration ECG intervals, and cardiac valve cross‐sectional areas. Vis‐a‐fronte filling of the atrium due to ventricular contraction was observed in all species. However, biphasic ventricular filling (i.e., due to central venous pressure and then atrial contraction) was only observed in rainbow trout and white sturgeon. Changes in atrial and ventricular performance varied between the species as temperature increased from 12°C to 20°C. Rainbow trout had the highest thermal sensitivity for fH (Q10 = 3.73), which doubled Q, and the largest increase in transvalvular blood velocity during ventricular filling. Conversely, northern pike had the lowest Q10 for fH (1.58) and did not increase Q. At ~60 beats/min, the rainbow trout heart had the shortest period of electrical activity, which also resulted in the longest recovery period (TP interval) between successive beats. The QT interval at ~60 beats/min was also longer in the white sturgeon versus the other species. These results suggest that interspecific differences in fish cardiac hemodynamics may be related to cardiac morphology, the duration of electrical impulses through the heart, cardiac thermal sensitivity, and valve dimensions.
A shift toward inhibitory receptors and impaired effector functions on NK cells contribute to immunosuppression during sepsis
Authors: Feng Ting , Liao Xuelian , Yang Xuewei , Yang Chuan , Lin Fang , Guo Yinkun , Kang Yan , Li Hong
Published: August 2019

Most information about the immune status of NK cells during sepsis has been obtained from animal models, athough data from clinical septic patients is limited. In this study, we aimed to decipher NK cell immunity of septic patients in a more comprehensive way. We found that cytotoxicity of NK cells dramatically decreased during sepsis, likely due to the reduction of cluster of differentiation (CD)3−CD56+ NK cells and a shift of phenotypic changes of NK group 2 member (NKG2) receptors, natural cytotoxicity receptors (NCRs) and killer immunoglobulin-like receptors (KIRs) toward inhibitory receptors demonstrated by CD3−CD56+NK cells in septic patients. Expression of the activation indicator CD69 and cytotoxic associated marker CD107a on CD3−CD56+ NK cells in healthy adults was significantly lower than that of septic patients. Although perforin and granzyme B on CD3−CD56+ NK cells from all groups exhibited equivalently high levels, CD3−CD56+ NK cells from septic patients exhibited a much lower fold increase of CD69 and CD107a compared with healthy adults after coculturing with K562 cells in vitro. Cytokine production of IFN-γ and TNF-α on CD3−CD56+ NK cells in septic patients was also impaired after stimulation by PMA and ionomycin. We found that the proportion of NK cells in lymphocytes was negatively associated with patient 28 d death in septic patients. Phenotypic changes of a shift toward inhibitory receptors and impairment of effector functions of NK cells might be an important mechanism of immunosuppression during sepsis.
The changing landscape of head and neck cancer radiotherapy patients: is high‐risk, prolonged feeding tube use indicative of on‐treatment weight loss?
Authors: Anderson Nigel J. , Jackson James E. , Wada Morikatsu , Schneider Michal , Poulsen Michael , Rolfo Maureen , Fahandej Maziar , Gan Hui , Khoo Vincent
Published: August 2019

Introduction

Precision radiotherapy relies heavily on optimal weight management. Our group previously developed a risk stratification model for patients at risk of prolonged feeding tube (FT) intervention. The study objective was to assess on‐treatment weight loss according to stratified risk of prolonged FT use.

Methods

One hundred and one (n = 101) definitive head and neck radiotherapy patients were included in this study. Patients were stratified into high risk (HRi: T‐classification ≥ 3 with level 2 Nodal disease), high‐intermediate risk (HIRi: T‐classification ≥ 3 without level 2 Nodes) and low‐intermediate risk (LIRi: T‐classification < 3 with level 2 Nodes) of prolonged FT use. Demographic variables and on‐treatment weight loss were evaluated according to risk status.

Results

Oropharyngeal carcinoma (OPC) was present in a larger proportion in the LIRi cohort (HRi: 71%, HIRi: 52%, LIRi: 81%, P = 0.008). LIRi patients were more likely to have human papilloma virus (HPV)‐associated disease (88%, P = 0.001). Never/minimal smoking (P = 0.003), good performance status (P < 0.001), healthy BMI (P = 0.050) and no pre‐existing dysphagia (P < 0.001) were predominant within the LIRi prognostic group. LIRi patients lost significantly more weight in total (HRi = 4.8% vs. LIRi = 8.2%, P = 0.002; HIRi = 5.2% vs. LIRi = 8.2%, P = 0.006) and when using a FT (HRi = 4.6% vs. LIRi = 8.8%, P < 0.001; HIRi = 5.3% vs. LIRi = 8.8%, P = 0.002).

Conclusions

Patients identified as low‐intermediate risk of prolonged, ≥25% FT use report significantly increased weight loss compared with patients at higher risk of FT use. This cohort is typical of the increasing number of patients presenting with HPV‐associated OPC. Results of this study suggest we should closely observe such patients throughout treatment, to ensure optimal weight maintenance, facilitating precision radiotherapy.
Cingulo‐opercular adaptive control for younger and older adults during a challenging gap detection task
Authors: Vaden Kenneth I. , Eckert Mark A. , Dubno Judy R. , Harris Kelly C.
Published: August 2019

Cingulo‐opercular activity is hypothesized to reflect an adaptive control function that optimizes task performance through adjustments in attention and behavior, and outcome monitoring. While auditory perceptual task performance appears to benefit from elevated activity in cingulo‐opercular regions of frontal cortex before stimuli are presented, this association appears reduced for older adults compared to younger adults. However, adaptive control function may be limited by difficult task conditions for older adults. An fMRI study was used to characterize adaptive control differences while 15 younger (average age = 24 years) and 15 older adults (average age = 68 years) performed a gap detection in noise task designed to limit age‐related differences. During the fMRI study, participants listened to a noise recording and indicated with a button‐press whether it contained a gap. Stimuli were presented between sparse fMRI scans (TR = 8.6 s) and BOLD measurements were collected during separate listening and behavioral response intervals. Age‐related performance differences were limited by presenting gaps in noise with durations calibrated at or above each participant's detection threshold. Cingulo‐opercular BOLD increased significantly throughout listening and behavioral response intervals, relative to a resting baseline. Correct behavioral responses were significantly more likely on trials with elevated pre‐stimulus cingulo‐opercular BOLD, consistent with an adaptive control framework. Cingulo‐opercular adaptive control estimates appeared higher for participants with better gap sensitivity and lower response bias, irrespective of age, which suggests that this mechanism can benefit performance across the lifespan under conditions that limit age‐related performance differences.
A calibrated database of Raman spectra for natural silicate glasses: implications for modelling melt physical properties
Authors: Giordano Daniele , González‐García Diego , Russell James K. , Raneri Simona , Bersani Danilo , Fornasini Laura , Di Genova Danilo , Ferrando Simona , Kaliwoda Melanie , Lottici Pier Paolo , Smit Matthijs , Dingwell Donald B.
Published: August 2019

The physical properties of silicate melts are of critical importance for understanding magmatic and volcanic processes on Earth and other planets. Most physical properties of melts are, ultimately, a consequence of the structural organization of the melt. Robust and fully generalizable strategies for the prediction of properties of naturally occurring melts as functions of composition, temperature, and pressure remain a challenging goal. Given the structural origin of macroscopic properties, Raman spectroscopy of glasses, which provides information on melt and glass structure, may provide a useful technique to understanding and quantify variations in macroscopic melt properties. Here, with the aim of providing a generalizable model for predicting the viscosity of silicate melts, we present the results of a Raman spectroscopy campaign performed on 30 anhydrous multicomponent silicate glasses resulting from quenching of remelted and homogenized volcanic rocks and synthetic equivalents. The sample suite comprises one of the largest databases of multicomponent melts for which (a) chemical compositions and (b) physical properties (i.e., viscosity, fragility, heat capacity, and glass transition temperature) are known. Raman spectra have been collected using green light sources at wavelengths of 532 nm. Spectra were collected on the same sample suite in four independent laboratories involving instruments from different manufacturers and, thus, using different spectrometers, detectors, and analytical conditions. Our results are also compared and integrated with published data on some of the same samples derived from two others setups using green light sources with 514.5 and 532 nm wavelegths. For the same sample, the Raman spectra acquired using different setups show different intensities and intensity ratios. However, a strategy based on the ratio between the low‐ and high‐wavenumber peaks (R) was developed to standardize the data to normalized Raman ratios (Rn) and thus to remove interlaboratory differences. Using these advances, we predict melt viscosity solely with the use of Raman spectral measurements of multicomponent silicate glasses, thus demonstrating the potential of the method in describing physical properties of silicate melts.
Microemulsions as delivery systems of lemon oil and β‐carotene into beverages: stability test under different light conditions
Authors: Calligaris Sonia , Manzocco Lara , Valoppi Fabio , Comuzzo Piergiorgio , Nicoli Maria Cristina
Published: August 2019

BACKGROUND

Microemulsions have been proposed as delivery systems for different lipophilic substances in transparent water‐based systems. The chemical stability of the delivered compounds is a key factor to broaden the application of microemulsions in the food sector. The stability of a model beverage containing a microemulsion delivering β‐carotene and lemon oil was tested under increasing light intensity up to 6000 lx at 20 °C.

RESULTS

The transparent microemulsion resulted physically stable during storage indicating that no coalescence phenomenon occurred. On the contrary, both colour and flavour of the microemulsion degraded as a consequence of limonene and β‐carotene oxidation. Kinetic data obtained at increasing light intensity were used to estimate the light dependence of beverage spoilage and the mathematical relationship obtained was used to predict spoilage rate under different light conditions. Finally, a shelf life predictive model was proposed.

CONCLUSIONS

Transparent microemulsions can be successfully used to deliver flavoured oil and colourants into beverages. However, the photostability of the delivered compounds should be carefully studied to estimate product shelf life. To this aim, the availability of models predicting shelf life as a function of enlightening conditions could largely contribute to speed up the process. © 2019 Society of Chemical Industry
Review of preclinical and clinical studies of using cell‐based therapy for secondary lymphedema
Authors: Chen Ching‐En , Chiang Nai‐Jung , Perng Cherng‐Kang , Ma Hsu , Lin Chih‐Hsun
Published: August 2019

Secondary lymphedema is associated with impaired lymph fluid drainage and remains incurable. Alternatively, cell‐based therapy may pave the way for lymphedema treatment. We found 11 animal and seven human studies had been conducted from 2008 to 2018. Most studies showed great potential for this treatment modality. Emerging studies have focused on novel techniques, such as coupling cell therapy with lymph node transfer, or adding growth factors to cell therapy.
Voice‐Related Quality of Life Increases With a Talking Tracheostomy Tube: A Randomized Controlled Trial
Authors: Pandian Vinciya , Cole Therese , Kilonsky Dana , Holden Kate , Feller‐Kopman David J. , Brower Roy , Mirski Marek
Published: August 2019

Objective

The primary objective of our study was to determine the quality of life (QOL) using a talking tracheostomy tube.

Methods

Randomized clinical trial (NCT2018562). Adult intensive care unit patients who were mechanically ventilated, awake, alert, attempting to communicate, English‐speaking, and could not tolerate one‐way speaking valve were included. Intervention comprised a Blue Line Ultra Suctionaid (BLUSA) talking tracheostomy tube (Smiths Medical, Dublin, OH, US). Outcome measures included QOL scores measured using Quality of Life in Mechanically Ventilated Patients (QOL‐MV) and Voice‐Related Quality of Life (V‐RQOL), Speech Intelligibility Test (SIT) scores, independence, and satisfaction.

Results

The change in V‐RQOL scores from pre‐ to postintervention was higher among patients using a BLUSA (Smiths Medical) compared to those who did not (P = 0.001). The QOL‐MV scores from pre‐ to postintervention were significantly higher among patients who used a BLUSA (Smiths Medical) compared to patients who did not use BLUSA (Smiths Medical) or a one‐way speaking valve (P = 0.04). SIT scores decreased by 6.4 points for each 1‐point increase in their Sequential Organ Failure Assessment scores (P = 0.04). The overall QOL‐MV scores correlated moderately with the overall V‐RQOL scores (correlation coefficient = 0.59). Cronbach alpha score for overall QOL‐MV was 0.71. Seventy‐three percent of the 22 intervention patients reported the ability to use the BLUSA (Smiths Medical) with some level of independence, whereas 41% reported some level of satisfaction with the use of BLUSA (Smiths Medical). The lengths of stay was longer in the intervention group.

Conclusion

Our study suggests that BLUSA (Smiths Medical) talking tracheostomy tube improves patient‐reported QOL in mechanically ventilated patients with a tracheostomy who cannot tolerate cuff deflation.

Level of Evidence

I

Laryngoscope, 130:1249–1255, 2020
Linking hydrological connectivity to gully erosion in savanna rangelands tributary to the Great Barrier Reef using structure‐from‐motion photogrammetry
Authors: Koci Jack , Sidle Roy C. , Jarihani Ben , Cashman Matthew J.
Published: August 2019

Gully erosion is a major land management challenge globally and a particularly important issue in dry tropical savanna rangelands tributary to the Great Barrier Reef, Australia. This study investigated linkages between hillslope hydrological connectivity pathways and gully geomorphic change in the Burdekin River Basin. High‐resolution (0.1 m) topographic and land cover data derived from low‐cost aerial (via unmanned aircraft system) structure‐from‐motion with multiview stereo photogrammetry (SfM) were used to map fine‐scale connectivity patterns and quantify headcut retreat at the hillslope scale (~150,000 m2). Very high resolution (0.01 m) topographic models derived from ground‐based (via handheld digital camera) SfM were used to quantify the morphology and geomorphic change of several gully arms (300–700 m2) between 2016 and 2018. Median linear, areal, and volumetric headcut (n = 21) retreat rates were 0.2 m, 0.8 m2, and 0.3 m3 yr−1, respectively. At all study sites, the points where modelled hydrological flow lines intersected gullies corresponded to observed geomorphic change, enabling spatially explicit identification of gully extension pathways as a result of overland flow. Application of an index of connectivity demarcated parts of the hillslope most connected to the gully network. Bare areas, roads, and cattle trails were identified as important runoff source areas and hydrological conduits driving gully extension. Ground‐based SfM accurately reconstructed complex morphologic features including undercuts, overhangs, rills, and flutes, providing insights into within‐channel erosion processes. This study contributes to an improved understanding and modelling of hydrogeomorphic drivers of gully erosion in degraded savanna rangelands, ultimately benefiting gully management.
Women on the board and executive tenure
Authors: Buchwald Achim , Hottenrott Hanna
Published: August 2019

The participation of women in top‐level corporate boards is subject to intense public debate. Countries are considering binding quotas to increase the share of women on boards or have already implemented such rules. Although research on board diversity suggests positive effects on corporate governance and firm performance, the mechanisms through which these benefits materialize remain mostly speculative. This study focuses on boards of directors in a large sample of listed companies in 15 European countries and finds that female representation on nonexecutive boards is associated with reduced turnover, an increase in tenure, and also a higher performance‐turnover sensitivity of executives.
Asymptotic stability of the human respiratory system with multiple state‐dependent delays
Authors: Hu Qingwen
Published: August 2019

We extend the Grodins model of human cardiovascular‐respiratory system with multiple blood transport time delays into a model with four threshold type state‐dependent delays, in order to investigate the asymptotic stability of carbon dioxide concentrations in the lung, brain, cerebrospinal fluid, and tissue compartments. We show that the extended model can be transformed into a model with four discrete time delays and obtain sufficient conditions for local and global asymptotic stabilities of the extended model by constructing Lyapunov functionals. Numerical simulations are presented to illustrate the general results.
Peripheral nerve stimulation limits of a high amplitude and slew rate magnetic field gradient coil for neuroimaging
Authors: Tan Ek T. , Hua Yihe , Fiveland Eric W. , Vermilyea Mark E. , Piel Joseph E. , Park Keith J. , Ho Vincent B. , Foo Thomas K. F.
Published: August 2019

Purpose

To establish peripheral nerve stimulation (PNS) thresholds for an ultra‐high performance magnetic field gradient subsystem (simultaneous 200‐mT/m gradient amplitude and 500‐T/m/s gradient slew rate; 1 MVA per axis [MAGNUS]) designed for neuroimaging with asymmetric transverse gradients and 42‐cm inner diameter, and to determine PNS threshold dependencies on gender, age, patient positioning within the gradient subsystem, and anatomical landmarks.

Methods

The MAGNUS head gradient was installed in a whole‐body 3T scanner with a custom 16‐rung bird‐cage transmit/receive RF coil compatible with phased‐array receiver brain coils. Twenty adult subjects (10 male, mean ± SD age = 40.4 ± 11.1 years) underwent the imaging and PNS study. The tests were repeated by displacing subject positions by 2‐4 cm in the superior–inferior and anterior–posterior directions.

Results

The x‐axis (left–right) yielded mostly facial stimulation, with mean ΔGmin = 111 ± 6 mT/m, chronaxie = 766 ± 76 µsec. The z‐axis (superior–inferior) yielded mostly chest/shoulder stimulation (123 ± 7 mT/m, 620 ± 62 µsec). Y‐axis (anterior–posterior) stimulation was negligible. X‐axis and z‐axis thresholds tended to increase with age, and there was negligible dependency with gender. Translation in the inferior and posterior directions tended to increase the x‐axis and z‐axis thresholds, respectively. Electric field simulations showed good agreement with the PNS results. Imaging at MAGNUS gradient performance with increased PNS threshold provided a 35% reduction in noise‐to‐diffusion contrast as compared with whole‐body performance (80 mT/m gradient amplitude, 200 T/m/sec gradient slew rate).

Conclusion

The PNS threshold of MAGNUS is significantly higher than that for whole‐body gradients, which allows for diffusion gradients with short rise times (under 1 msec), important for interrogating brain microstructure length scales.
Minority carrier lifetime in indium doped silicon for photovoltaics
Authors: Murphy John D. , Pointon Alex I. , Grant Nicholas E. , Shah Vishal A. , Myronov Maksym , Voronkov Vladimir V. , Falster Robert J.
Published: August 2019

For photovoltaics, switching the p‐type dopant in silicon wafers from boron to indium may be advantageous as boron plays an important role in the light‐induced degradation mechanism. With the continuous Czochralski crystal growth process it is now possible to produce indium doped silicon substrates with the required doping levels for solar cells. This study aims to understand factors controlling the minority carrier lifetime in such substrates with a view to enabling the quantification of the possible benefits of indium doped material. Experiments are performed using temperature‐dependent Hall effect and injection‐dependent carrier lifetime measurements. The recombination rate is found to vary linearly with the concentration of un‐ionized indium which exists in the sample at room temperature due to indium's relatively deep acceptor level at 0.15 eV from the valence band. Lifetime in indium doped silicon is also shown to degrade rapidly under illumination, but to a level substantially higher than in equivalent boron doped silicon samples. A window of opportunity exists in which the minority carrier lifetime in degraded indium doped silicon is higher than the equivalent boron doped silicon, indicating it may be suitable as the base material for front contact photovoltaic cells.
Synthesis and bioactivity studies of novel Schiff bases and their complexes
Authors: Al Zoubi Wail , Jirjees VianYamin , Suleman VeyanTaher , Al‐Hamdani Abbas Ali Salih , Ahmed Suzan Duraid , Kim Yang Gon , Ko Young Gun
Published: August 2019

The new Schiff base (L) “4‐[(2,4‐dimethoxy‐benzylidene)‐amino]‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐pyrazol‐3‐one” was synthesized from 2,4‐dimethoxy‐benzaldehyde and 4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydropyrazol‐3‐one, and the geometry of Schiff base was characterized and determined by proton nuclear magnetic resonance (1H‐NMR), mass, Fourier transform infrared (FT‐IR), and ultraviolet‐visible (UV‐vis) spectroscopy. Schiff complexes of Ni(II), Pd(II), Pt(IV), Zn(II), Cd(II), and Mg(II) have been prepared by reaction of ion metals with as‐prepared Schiff base. The results showed that synthesized complexes offered 1:2 metal‐ligand ratios. Furthermore, the Schiff complexes were a tetrahedral in complexes Ni(II), Zn(II), Cd(II), and Hg(II), octahedral Pt(II), and square planer complex Pd(II). Additionally, density functional theory (DFT) was applied for calculations of both spectroscopic properties and electronic structure of prepared Schiff bases. Moreover, the Schiff base and its metal complexes have been verified in vitro against Streptococcus, Esherichia coli, Candida albicans, and Candida tropicalis in order to assess their antibacterial potential. The findings indicate that the biological activity augments on complexation reaction.
Bio‐based vinylphenol family: Synthesis via decarboxylation of naturally occurring cinnamic acids and living radical polymerization for functionalized polystyrenes
Authors: Takeshima Hisaaki , Satoh Kotaro , Kamigaito Masami
Published: August 2019

A series of bio‐based vinylphenols or hydroxystyrenes is prepared by simple decarboxylation of various naturally occurring cinnamic acids such as o‐, m‐, and p‐coumaric; caffeic; ferulic; and sinapinic acids, which possess hydroxy groups and other substituents at different positions on the aromatic ring. After protection of the phenolic moieties with trialkylsilyl groups, reversible addition–fragmentation chain‐transfer polymerization is accomplished with cumyl dithiobenzoate to afford various bio‐based hydroxyl‐protected polystyrenes with controlled molecular weights and narrow molecular weight distributions. Subsequent deprotection of the silyl groups under mild conditions results in a series of well‐defined functionalized polystyrenes possessing different numbers (mono‐, di‐, tri‐) of hydroxy groups at different positions (o, m, p). The obtained functionalized polystyrenes show unique thermal properties depending on the substituents, and those with phenol and catechol groups serve as reducing agents for silver ions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 91–100
Error propagation and uncertainty analysis: Application to fault tree analysis
Authors: Freeman Raymond A. “Randy”
Published: August 2019

Fault tree analysis (FTA) is a widely used method for the evaluation of safety systems. FTA is based on modeling the behavior of a system by a combination of logic gates (AND, OR) in a logic tree that describes the system. Failure data of low‐level events are used to compute the frequency of the top event of concern. The failure rate data describe the failure of the system components such as pumps, valves, vessels, and instruments. All of the failure rate data are uncertain. This article presents a methodology for the evaluation of uncertainty in the top event of concern using propagation of error and uncertainty analysis methods. The fundamental theory is presented, and a simple fault tree uncertainty analysis is completed to demonstrate the methodology. The uncertainty analysis methodology allows for the identification of the components or assumptions that dominate the risk.
Probing and Tuning the Spin Textures of the K and Q Valleys in Few‐Layer MoS2
Authors: Chen Qihong , Ali El Yumin Abdurrahman , Zheliuk Oleksandr , Wan Puhua , Liang Minpeng , Peng Xiaoli , Ye Jianting
Published: August 2019

The strong spin–orbit coupling along with broken inversion symmetry in transition metal dichalcogenides (TMDs) results in spin polarized valleys, which are the origins of many interesting properties such as Ising superconductivity, circular dichroism, valley Hall effect, etc. Herein, it is shown that encapsulating few‐layer MoS2 between hexagonal boron nitride (h‐BN) and gating the electrical contacts by ionic liquid pronounce Shubnikov–de Haas (SdH) oscillations in magnetoresistance. Notably, the SdH oscillations remain unchanged in tilted magnetic fields, demonstrating that the spins of the Q/Q′ valleys are firmly locked to the out‐of‐plane direction; therefore, Zeeman energy is insensitive to the in‐plane magnetic field. Ionic liquid gating induces superconductivity on the surface of unencapsulated MoS2. The spins of Cooper pairs are strongly pinned to the out‐of‐plane direction by the effective Zeeman field, hence are protected from being realigned by an in‐plane magnetic field, namely, Ising protection. As a result, superconductivity persists in an in‐plane magnetic field up to 14 T, in which Tc only decreases by ≈0.3 K from Tc0 as ≈7 K. By applying back gate, the strength of Ising protection can be effectively tuned, where an increase in 70% is observed when back gate changes from +90 to −90 V.
The Effect of Electron Irradiation on Cesium Fluoride‐Free and Cesium Fluoride‐Treated Cu(In1−x,Gax)Se2 Solar Cells
Authors: Khatri Ishwor , Lin Tzu-Ying , Nakada Tokio , Sugiyama Mutsumi
Published: August 2019

Herein, the effects of electron irradiation on cesium fluoride (CsF)‐free and CsF‐treated Cu(In1−x,Gax)Se2 (CIGS) solar cells with fluence from 1 × 1013 to 1 × 1017 cm−2 are investigated. Both CsF‐free and CsF‐treated CIGS solar cells exposed to fluence up to 3 × 1015 cm−2 show self‐healing properties, due to the soaking effect from electron bombardment. This feature indicates the robustness of CIGS solar cells for long‐term space explorations. On the other hand, electron irradiation with fluence above 1 × 1016 cm−2 suppresses the solar cell performance of both CsF‐free and CsF‐treated samples, which is expected to be due to the formation of irradiation‐induced defects on the CIGS thin film. This result suggests that the formation of irradiation‐induced defects is independent of the incorporation of heavier alkali metals into the CIGS thin films. The defect passivation and/or introduction rates at different fluences are investigated.
Tinospora cordifolia preserves pancreatic beta cells and enhances glucose uptake in adipocytes to regulate glucose metabolism in diabetic rats
Authors: Sharma Bhesh Raj , Park Chul Min , Kim Hyeon‐A , Kim Hyun Jung , Rhyu Dong Young
Published: August 2019

The purpose of this study was to evaluate the pancreatic beta cell protective and glucose uptake enhancing effect of the water extract of Tinospora cordifolia stem (TCSE) by using rat insulinoma (RIN)‐m5F cells and 3 T3‐L1 adipocytes. RIN‐m5F cells were stimulated with interleukin‐1β and interferon‐γ, and the effect of TCSE on insulin secretion and cytokine‐induced toxicity was measured by ELISA and MTT assay, respectively. The glucose uptake and protein expression were measured by fluorometry and western blotting. Antidiabetic effect of TCSE was measured using streptozotocin‐induced diabetic rats. TCSE dose dependently increased cell viability and insulin secretion in RIN‐m5F cells. In addition, TCSE increased both the glucose uptake and glucose transporter 4 translocation in 3 T3‐L1 adipocytes via PI3K pathway. Finally, TCSE significantly lowered blood glucose and diet intake and increased body weight in streptozotocin‐induced diabetic rats. The level of serum insulin and hepatic glycogen was increased, whereas the level of serum triglyceride, total cholesterol, dipeptidyl peptidase‐4, and thiobarbituric acid reactive substances was decreased in TCSE‐administered rats. TCSE also increased glucose transporter 4 protein expression in the adipose tissue and liver of TCSE‐fed diabetic rats. Our results suggested that TCSE preserved RIN‐m5F cells from cytokine‐induced toxicity and enhanced glucose uptake in 3 T3‐L1 adipocytes, which may regulate glucose metabolism in diabetic rats.
Five New Silver Rare‐Earth Iodates, AgLn(IO3)4 (Ln=Pr, Sm, Dy, Er and Tm): Synthesis, Structures and Properties
Authors: Wu Qi , Liu Xian , Xu Siran , Pi Hongbing , Li Yanjun
Published: August 2019

Five new silver rare‐earth iodates AgLn(IO3)4 (Ln= Pr, Sm, Dy, Er and Tm) have been synthesized first time by hydrothermal method, and their structures are confirmed by single crystal X‐ray diffraction. They are isomorphic of previous characterized AgM(IO3)4 (With M= Y, La, Nd, Eu, Gd, Bi) compounds and all crystallized in noncentrosymmetric (NCS) structure. Their structures contain LnO8 polyhedrons, which are interconnected through IO3 groups to form a complex two dimensional (2D) layer. Their powders all show nonlinear optical (NLO) effects which are 2.3 ‐ 4 times stronger than KH2PO4 (KDP) respectively. Energy dispersive X‐ray spectroscopy (EDS), Infrared region (IR) spectra, Ultra‐visible (UV/Vis) spectra and thermogravimetric analysis (TGA) are also performed.
Light‐Induced Defect Generation in CH3NH3PbI3 Thin Films and Single Crystals
Authors: Rappich Jörg , Lang Felix , Brus Viktor V. , Shargaieva Oleksandra , Dittrich Thomas , Nickel Norbert H.
Published: August 2019

In a period of only a few years, the power conversion efficiency of organic–inorganic perovskite solar cells has surpassed a value of 24.2%. However, a major drawback is the lack of long‐term stability, which is partially related to the dissociation of organic cations under prolonged illumination. This degradation mechanism is not limited to ambient temperatures. At low temperatures (T = 5 K), illumination of methyl ammonium lead iodide (CH3NH3PbI3) thin films with a photon energy of Eph = 3.4 eV results in the formation of localized trap states located about 100 meV within the bandgap. These light‐induced defects are metastable, and annealing at T ≥ 15 K removes the localized states. Defect creation is not limited to polycrystalline perovskites but is also observed in single‐crystal CH3NH3PbI3. The experimental data are discussed in terms of a two‐level model where the metastable state is separated from the annealed state by an energy barrier.
Autonomous Formation and Annealing of Colloidal Crystals Induced by Light‐Powered Oscillations of Active Particles
Authors: Altemose Alicia , Harris Aaron J. , Sen Ayusman
Published: August 2019

Self‐organization through communication is observed in many systems throughout nature, often resulting in a collective response to a change in the environment. Herein, we demonstrate a synthetic system that exhibits chemical communication between small active and larger inactive particles which drives the reversible assembly of the latter into colloidal crystals. Specifically, we report the autonomous hexagonal packing of inert silica particles due to the oscillatory behavior of neighboring silver phosphate micromotors under UV light in the presence of hydrogen peroxide. The colloidal crystals are formed under UV illumination and relax into a disordered state when the light is turned off. Furthermore, oscillatory waves generated by the active particles cause “autonomous annealing”, or elimination of defects between crystal boundaries of the silica colloidal crystals.
Restorative Education, Reconciliation, and Healing: Indigenous Perspectives on Decolonizing Leadership Education
Authors: Cross Terry L. , Pewewardy Cornel , Smith Adrian T.
Published: August 2019

This chapter summarizes the complex history of colonization of the Indigenous peoples of what is now the United States from the perspective of leadership education. The authors review the dilemmas and challenges of bridging fundamental cultural differences regarding leadership education and concrete steps toward decolonizing leadership education.
Uplifts of maximal supergravities and transitions to non-geometric vacua
Authors: Dall’Agata Gianguido , Inverso Gianluca , Spezzati Paolo
Published: August 2019

Abstract

We describe a new procedure to obtain consistent backgrounds that uplift vacua and deformations of various maximal gauged supergravities by taking a known solution and performing singular limits along the moduli space of the corresponding 4-dimensional theory. We then apply this procedure to the S
3 × H
2,2 background that provides the uplift of 4-dimensional Minkowski vacua of maximal supergravity with gauge group [SO(4) × SO(2)] ⋉ ℝ16. We find that the newly generated vacua are generally only locally geometric and correspond to asymmetric orbifolds, Q-flux backgrounds or combinations thereof. We also provide the uplift to eleven dimensions of all the four-parameter Cremmer-Scherk-Schwarz gaugings.
The conifer-curve: fast prediction of hydraulic conductivity loss and vulnerability to cavitation
Authors: Rosner Sabine , Johnson Daniel M. , Voggeneder Klara , Domec Jean-Christophe
Published: August 2019

Key message

The relationship between relative water loss (RWL) and hydraulic conductivity loss (PLC) in sapwood is robust across conifer species. We provide an empirical model (conifer-curve) for predicting PLC from simple RWL measurements. The approach is regarded as a new relevant phenotyping tool for drought sensitivity and offers reliable and fast prediction of diurnal, seasonal, or drought-induced changes in PLC.

Context

For conifer species drought is one of the main climate risks related to loss of hydraulic capacity in sapwood inducing dieback or mortality. More frequently occurring drought waves call for fast and easily applicable methods to predict drought sensitivity.

Aims

We aimed at developing a fast and reliable method for determination of the percent loss of hydraulic conductivity (PLC) and eventually the drought sensitivity trait P50, i.e., the water potential that causes 50% conductivity loss.

Methods

We measured the loss of water transport capacity, defined as the relative water loss (RWL) together with PLC in trunk wood, branches, and saplings of eight different conifer species. Air injection was used to induce specific water potentials.

Results

The relationship between RWL and PLC was robust across species, organs, and age classes. The equation established allows fast prediction of PLC from simple gravimetrical measurements and thus post hoc calculation of P50 (r2 = 0.94).

Conclusion

The approach is regarded as a relevant new phenotyping tool. Future potential applications are screening conifers for drought sensitivity and a fast interpretation of diurnal, seasonal, or drought-induced changes in xylem water content upon their impact on conductivity loss.
Using polytomous latent class analysis to compare patterns of substance use and co‐occurring health‐risk behaviors between students in alternative and mainstream high schools
Authors: Johnson Karen E. , Sales Adam , Rew Lynn , Haussler Garing Jennifer , Crosnoe Robert
Published: August 2019

Introduction

Alternative high school (AHS) students, an understudied and underserved population, experience educational, social, and health disparities relative to students in mainstream high schools. Disparities in single types of substance use are particularly high, yet no known studies have compared patterns of substance use or relationships between these patterns and other health‐risk behaviors between AHS and mainstream high schools.

Methods

Using data from the Texas Alternative School Health Survey (n = 515; mean age 17.1 years, 49% male, 59% Hispanic, 23% White, 15% Black) and the Texas Youth Risk Behavior Survey (n = 2,113; mean age 16 years, 47% male, 64% Hispanic, 22% White, 7% Black), we used latent class analyses to compare patterns of substance use in AHSs and mainstream high schools. We used latent class regression to examine relationships between patterns of substance use and involvement in other health‐risk behaviors in each school setting.

Results

Students in AHSs and mainstream high schools had similar patterns of substance use, and youth in higher risk categories engaged in higher levels of other health‐risk behaviors. A substantially greater proportion of AHS students, however, fell into the moderate and high use categories, in support of continuing disparities for AHS students.

Conclusions

Additional support is needed in AHSs to address the prevalence of high‐risk patterns of substance use and associated health‐risk behaviors. For example, ongoing public health surveillance is needed in AHSs, just as is done in mainstream high schools, to monitor trends in substance use and impact of policies and interventions.