bluuebunny/crossref_metadata_2025 huggingface dataset:
Respiratory Rate Threshold Accurately Estimates the Second Lactate Threshold
Authors: Elmer David , Toney Marissa
Published: January 2018

Purpose The modified Dmax method can accurately determine the second lactate threshold (LT2), which is valuable for predicting aerobic performance and prescribing exercise. The purpose of this study is to determine if the modified Dmax method can accurately find thresholds in VE (VT2), VCO2 (VCO2T), RER (RERT), and RR (RRT) to estimate LT2.

Methods Forty-one participants (females n=23, males n=18) completed an incremental exercise test to determine LT2, VT2, VCO2T, RERT, RRT, and blood lactate=4 mmol/L (La4).

Results VT2 and RRT were strongly correlated with VO2 and HR at LT2, with very small bias and limits of agreement, indicating that VT2 and RRT provide accurate estimates of LT2 (VO2 at VT2-LT2 mean difference=0.37±1.91 ml/kg/min, p=0.95; HR at VT2-LT2 mean difference=0.25±2.58 bpm, p=0.99; VO2 at RRT-LT2 mean difference 0.26±2.11 ml/kg/min, p=0.99; HR at RRT-LT mean difference 0.44±3.31 bpm, p=0.99). VCO2T, RERT, and La4 were either accurate for VO2 or HR estimates of LT2, but not both.

Conclusions VT2 and RRT provide accurate estimates of LT2 using the modified Dmax method. There is the potential to use RRT in developing field tests to estimate LT2 in practical settings.
Time-resolved spectral response of asymmetrical optical microcavity structures under laser-driven shock compression
Authors: Scripka David A. , Lee Gyuhyon , Kang Zhitao , Summers Christopher J. , Thadhani Naresh N.
Published: January 2018

The time-resolved spectral responses of three asymmetrical optical microcavity (AOMC) structures under laser-driven shock compression were investigated. The objective was to compare the performance of these multilayer structures and explore the potential in dynamic shock “pressure” sensing, given their unique ability to capture spatially heterogeneous pressure distributions across 2D surfaces. Different AOMC structures were fabricated, with amorphous SiO2, amorphous Al2O3, and PMMA cavity layers between deposited silver reflecting layers producing the characteristic spectral features of the structures. An experimental setup employing laser-driven shock compression was used to generate nanosecond scale pressure loads of ∼1-10 GPA, and the corresponding time-resolved spectral response and in-situ particle velocity of the AOMCs was simultaneously recorded. Each of the AOMC multilayers showed clear spectral shifts as a function of pressure with nanosecond level correlation to the independently measured velocimetry data. These results indicate that the time-resolved physical state of the cavity layer drives the spectral response of the optical microcavity structures. The results also validate qualitative predictions of the multilayer structures’ response to dynamic compressive loads and their potential for use in time-resolved sensing of pressure.
Power functional theory for Newtonian many-body dynamics
Authors: Schmidt Matthias
Published: January 2018

We construct a variational theory for the inertial dynamics of classical many-body systems out of equilibrium. The governing (power rate) functional depends on three time- and space-dependent one-body distributions, namely, the density, the particle current, and the time derivative of the particle current. The functional is minimized by the true time derivative of the current. Together with the continuity equation, the corresponding Euler-Lagrange equation uniquely determines the time evolution of the system. An adiabatic approximation introduces both the free energy functional and the Brownian free power functional, as is relevant for liquids governed by molecular dynamics at constant temperature. The forces beyond the Brownian power functional are generated from a superpower (above the overdamped Brownian) functional.
Angle comparison using an autocollimator
Authors: Geckeler Ralf D , Just Andreas , Vasilev Valentin , Prieto Emilio , Dvorácek František , Zelenika Slobodan , Przybylska Joanna , Duta Alexandru , Victorov Ilya , Pisani Marco , Saraiva Fernanda , Salgado Jose-Antonio , Gao Sitian , Anusorn Tonmueanwai , Tan Siew Leng , Cox Peter , Watanabe Tsukasa , Lewis Andrew , Chaudhary K P , Thalmann Ruedi , Banreti Edit , Nurul Alfiyati , Fira Roman , Yandayan Tanfer , Chekirda Konstantin , Bergmans Rob , Lassila Antti
Published: January 2018

Autocollimators are versatile optical devices for the contactless measurement of the tilt angles of reflecting surfaces. An international key comparison (KC) on autocollimator calibration, EURAMET.L-K3.2009, was initiated by the European Association of National Metrology Institutes (EURAMET) to provide information on the capabilities in this field. The Physikalisch-Technische Bundesanstalt (PTB) acted as the pilot laboratory, with a total of 25 international participants from EURAMET and from the Asia Pacific Metrology Programme (APMP) providing measurements. This KC was the first one to utilise a high-resolution electronic autocollimator as a standard. In contrast to KCs in angle metrology which usually involve the full plane angle, it focused on relatively small angular ranges (±10 arcsec and ±1000 arcsec) and step sizes (10 arcsec and 0.1 arcsec, respectively). This document represents the approved final report on the results of the KC.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Parameters Associated With Mandibular Osteoradionecrosis
Authors: Mendenhall William M. , Suárez Carlos , Genden Eric M. , de Bree Remco , Strojan Primož , Langendijk Johannes A. , Mäkitie Antti A. , Smee Robert , Eisbruch Avraham , Lee Anne W.M. , Rinaldo Alessandra , Ferlito Alfio
Published: January 2018

The objective of this review is to discuss factors related to the risk of osteoradionecrosis (ORN) and how to minimize the likelihood of this complication. A PubMed search for publications pertaining to ORN within the last 3 years was conducted revealing 44 publications. The bibliographies of these publications were reviewed to identify additional references spanning a longer time period. The incidence of ORN is 5% to 10% with a median latency period of 1 to 2 years or less. The likelihood of ORN depends on a number of factors including primary site and extent of disease, dental status, treatment modality, radiotherapy (RT) dose, volume of mandible included in the planning target volume, RT fractionation schedule and technique, and teeth extractions. The risk of ORN may be reduced by limiting the RT dose and volume of mandible irradiated without increasing the risk of a local-regional recurrence due to a marginal miss.
Lack of paclitaxel effects on intracranial self-stimulation in male and female rats: comparison to mechanical sensitivity
Authors: Legakis Luke P. , Bigbee John W. , Negus S. Stevens
Published: January 2018

Paclitaxel is a cancer chemotherapy with adverse effects that include peripheral neuropathy, neuropathic pain, and depression of behavior and mood. In rodents, hypersensitive paw-withdrawal reflexes from mechanical stimuli serve as one common measure of paclitaxel-induced pain-related behavior. This study tested the hypothesis that paclitaxel would also depress rates of positively reinforced operant responding as a measure of pain-related behavioral depression. Male and female Sprague-Dawley rats were equipped with electrodes targeting the medial forebrain bundle, trained to lever press for electrical brain stimulation in an assay of intracranial self-stimulation (ICSS), and treated with four injections of varying paclitaxel doses (0.67, 2.0, or 6.0 mg/kg/injection×4 injections on alternate days). Mechanical sensitivity, body weight, and ICSS were evaluated before, during, and for 3 weeks after paclitaxel treatment. Paclitaxel doses sufficient to produce mechanical hypersensitivity did not reliably depress ICSS in male or female rats. Moreover, the degree of behavioral suppression in individual rats did not correlate with mechanical sensitivity. Paclitaxel treatment regimens commonly used to model chemotherapy-induced neuropathic pain in rats are not sufficient to depress ICSS.
Association between polycystic ovary syndrome and hot flash presentation during the midlife period
Authors: Yin Ophelia , Zacur Howard A. , Flaws Jodi A. , Christianson Mindy S.
Published: January 2018

Objective:

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in reproductive-aged women; however, the impact of PCOS on menopausal symptoms remains poorly understood. This study aims to determine the influence of PCOS on hot flash presentation in midlife women.

Methods:

Participants were recruited from the Midlife Women's Health Study involving 780 women aged 45 to 54 years. All women completed detailed questionnaires on hot flash symptoms. Between June 2014 and March 2015, participants were screened for history of PCOS based on the Rotterdam criteria. Fisher's exact tests and Wilcoxon rank-sum tests were used for analysis. Multivariate logistic regression was performed to identify factors associated with hot flashes at midlife.

Results:

In all, 453 women (69%) consented to the telephone interview and 9.3% (n = 42) met diagnostic criteria for PCOS; 411 were included as controls. Mean age was 48.0 and body mass index was 27.3 for women with PCOS. The majority of participants were white (72%). There was no difference between PCOS and control women for levels of follicle-stimulating hormone, testosterone, progesterone, or estradiol. Multivariate logistic regression demonstrated that PCOS was not associated with increased odds of hot flash incidence. Smoking was the only variable associated with experiencing hot flashes (odds ratio 2.0, 95% confidence interval 1.05-3.98).

Conclusions:

A history of PCOS was not associated with increased hot flash symptoms during the midlife period. Additional research should continue to investigate the health and quality of life associated with a history of PCOS in the aging population.
Temporal Fluctuations in Indoor Background Gamma Radiation Using NaI(Tl)
Authors: Smith Travis , Cao Sana , Kearfott Kimberlee J.
Published: January 2018

An enhanced understanding of background gamma radiation is necessary for accurate radionuclide activity quantification. Background spectra are routinely subtracted from spectra of samples prepared in known geometries, with data collection time chosen to optimize statistics for counting uncertainties. The work presents measured background spectra collected inside and outside shields of varying geometry and composition, showing the effects of these on background. Gamma background measurements with and without blank samples are included along with spectra from different sizes and shapes of NaI(Tl) detectors. If the environment is being monitored for quick and confident detection of recently appearing radiation sources, a thorough knowledge of the background radiation and its temporal variation is essential. To study the requirements of such background measurements, sequential background gamma radiation collections were obtained on an hourly basis for a total of 316 h from an unshielded 5.5 × 11 × 40 cm3 NaI(Tl) detector located inside a laboratory setting where small sources are routinely stored and used. Finally, a strategy for optimizing data collection times and analyzing background gamma radiation spectra for long-term radionuclide monitoring is presented.
DIRECTIONAL VARIABILITY OF FUNDUS REFLECTANCE IN ACUTE MACULAR NEURORETINOPATHY: EVIDENCE FOR A CONTRIBUTION OF THE STILES–CRAWFORD EFFECT
Authors: Bottin Caroline , Grieve Kate , Rossant Florence , Pedinielli Alexandre , Mrejen Sarah , Paques Michel
Published: January 2018

Purpose:

To document directional reflectivity of fundus lesions in a case of acute macular neuroretinopathy.

Methods:

Case report. Clinical and imaging data from a patient with acute macular neuroretinopathy were reviewed. Imaging comprised infrared scanning laser ophthalmoscopy, optical coherence tomography and flood-illumination adaptive optics images acquired through different entry pupils in the cardinal directions (approximately 2° eccentricity).

Results:

The patient reported acute bilateral paracentral scotoma revealing dark, wedge-shaped macular plaques which by optical coherence tomography were associated with focal loss of the visibility of the cone outer segment tip and inner/outer segment lines. Comparing scanning laser ophthalmoscopy images taken at different entry points in the pupil showed that macular plaques varied from hyporeflectance to isoreflectance. Cone counts by flood-illumination adaptive optics within plaques and optical coherence tomography features of the cone outer segment tip showed also a strong directional variability, peaking at near-normal values. Within each modality, fusion images showed that directional variability covered most of macular plaques.

Conclusion:

The characteristic fundus abnormalities of acute macular neuroretinopathy may show a strong directional variability. Our findings suggest that the Stiles–Crawford effect may be an important factor in signs and symptoms of acute macular neuroretinopathy.
In Vitro Evaluation of a Hypochlorous Acid Hygiene Solution on Established Biofilms
Authors: Romanowski Eric G. , Stella Nicholas A. , Yates Kathleen A. , Brothers Kimberly M. , Kowalski Regis P. , Shanks Robert M. Q.
Published: January 2018

Objectives:

The purpose of this study was to determine whether a commercial formulation of hypochlorous acid hygiene solution (0.01%), Avenova, can destroy existing biofilms formed by ocular clinical bacterial isolates, including blepharitis isolates of Staphylococcus aureus and coagulase-negative staphylococci, and a keratitis isolate of Pseudomonas aeruginosa.

Methods:

Biofilms grown in bacterial growth media on disposable contact lens cases were challenged with hypochlorous acid hygiene solution. At various time points, surviving bacteria were quantified by serial dilution and colony counts. Staphylococcus aureus biofilms formed on glass were challenged using a hypochlorous acid hygiene solution and imaged using vital staining and confocal laser scanning microscopy.

Results:

Bactericidal activity (≥3 Log10; 99.9%) was observed for all tested bacterial species after a 30-min exposure. Staphylococcus aureus biofilms had a bactericidal level of killing by 10 min (P<0.01), Staphylococcus capitis by 5 min (P<0.001), Staphylococcus epidermidis by 30 min (P<0.001), and P. aeruginosa by 10 min (P<0.01). Confocal microscopy and crystal violet staining analysis of bacterial biofilms treated with hypochlorous acid solution both demonstrated that biofilm bacteria were readily killed, but biofilm structure was largely maintained.

Conclusions:

Hypochlorous acid (0.01%) hygiene solution was able to achieve bactericidal levels of killing of bacteria in biofilms but did not disrupt biofilm structures. Susceptibility of tested staphylococcal blepharitis isolates varied by species, with S. capitis being the most susceptible and S. epidermidis being the least susceptible.
Stenotrophomonas maltophilia—A Case Series of a Rare Keratitis Affecting Patients With Bandage Contact Lens
Authors: Hogg Henry D. J. , Siah We Fong , Okonkwo Arthur , Narayanan Manjusha , Figueiredo Francisco C.
Published: January 2018

Objectives:

Stenotrophomonas maltophilia is an opportunistic pathogen known to form biofilms on contact lens and case surfaces that may result in permanent visual loss in cases of microbial keratitis. Because of its multiple drug resistance and extremely low incidence, there is little consensus on treatment. We investigated the predisposing factors, management, and visual outcomes in a small case series of patients to better inform the management of this rarely reported keratitis.

Methods:

Retrospective analysis of medical records was performed at a single tertiary referral center between 2011 and 2017. The case notes of each microbiology confirmed S. maltophilia keratitis were examined.

Results:

Six cases were identified (four men) with a median age of 62 years (range 1 month–90 years) and pre-existing ocular surface disease in all cases. At presentation, four patients were using bandage contact lenses and three were on topical antibiotic and steroid medications. Initial antibiotic treatment was intensive topical 0.3% ofloxacin and 5% cefuroxime, which was modified based on corneal scrape culture and sensitivity and clinical findings. One patient chose not to complete the treatment course. The 5 remaining patients had complete resolution of ulceration over a mean of 2.9 months (SD 0.8 months).

Conclusions:

Contact lens in the context of ocular surface problems, prolonged topical antibiotic and steroid treatments may predispose to S. maltophilia, a rare cause of keratitis. We report successful treatment with case-specific combinations of topical antibiotics such as fluoroquinolone, cotrimoxazole, and/or cephalosporin agents, although visual outcomes remain poor due to corneal scar.
Health Service Utilization Among People With Noncommunicable Diseases in Rural Vietnam
Authors: Van Minh Hoang , Oh Juhwan , Giang Kim Bao , Bao Ngoc Nguyen , Minh Hoang Nguyen , Giang Huong Tran Thi , Van Huy Nguyen , Son Dinh Thai , Lee Jong-Koo , Hoat Luu Ngoc
Published: January 2018

Context:

Chronic noncommunicable diseases (NCDs) have been shown to be major causes of morbidity and mortality in hospitals for the whole country.

Objective:

This study aims to describe the situation of health service utilization among people with NCDs in a rural area and identify association between the situation of health service utilization among people with chronic diseases and their socioeconomic status.

Design:

This was a cross-sectional study.

Setting:

A rural district located in the North of Vietnam.

Participants:

People 15 years of age and older. Health service utilization was analyzed only among people who reported having NCD.

Main Outcome Measures:

Data were collected through a personal household interview conducted by 12 trained field workers. The dependent variable is health care service utilization among people with chronic NCDs. The explanatory variables include both household attributes such as household economic conditions, and so forth, and individual characteristics.

Results:

Eighteen percent of the adults and 51% of the elderly respondents reported having at least 1 of the NCDs. The proportions of people with NCDs who used at least 1 outpatient service and used at least 1 inpatient health service during the last 12 months were 68.1% and 10.7%, respectively (the nonutilization rates of 31.9% and 89.3%, respectively). The statistically significant correlates of health care service utilization among people with NCDs were ethnicity (ethnic minority was significantly associated with a lower odds of health care service utilization) and health insurance (no health insurance was significantly associated with lower odds of health care service utilization).

Conclusion:

Given the evidence from this study, actions to improve access to health care services among people with NCDs are clearly needed. The capacity of primary health care system for the prevention and control of NCDs should be ranked a top priority.
Universal Health Insurance Coverage in Vietnam: A Stakeholder Analysis From Policy Proposal (1989) to Implementation (2014)
Authors: Hoang Chi K. , Hill Peter , Nguyen Huong T.
Published: January 2018

Context:

In 1989, health insurance (HI) was introduced in Vietnam and began to be implemented in 1992. There was limited progress until the 2014 Law on HI that was revised with the aim of universal health insurance coverage (UHIC) by 2020. This article explores stakeholder roles and positions from the initial introduction of HI to the implementation of the Master Plan accelerating UHIC.

Objective:

To better understand the influence of stakeholders in accelerating UHIC to achieve equity in health care.

Design:

Using a qualitative study design, we conducted content analysis of HI-related documents and interviewed social security and health system key informants, government representatives, and community stakeholders to determine their positions and influence on UHIC.

Results:

Our findings demonstrate different levels of support of stakeholders that influence in the HI formulation and implementation, from opposition when HI was first introduced in 1989 to collaboration of stakeholders from 2013 when the Master Plan for UHIC was implemented. Despite an initial failure to secure the support of the Parliament for a Law on HI, a subsequent series of alternative legislative strategies brought limited increases in HI coverage. With government financial subsidization, the involvement of multiple stakeholders, political commitment, and flexible working mechanisms among stakeholders have remained important, with an increasing recognition that HI is not only a technical aspect of the health system but also a broader socioeconomic and governance issue. The different levels of power and influence among stakeholders, together with their commercial and political interests and their different perceptions of HI, have influenced stakeholders' support or opposition to HI policies.

Conclusions:

Despite high-level policy support, stakeholders' positions may vary, depending on their perceptions of the policy implications. A shift in government stakeholder positions, especially at the provincial level, has been necessary to accelerate UHIC progress and build institutional capacity.
PD-1/PD-L1 Axis in Lung Cancer
Authors: Santini Fernando C. , Hellmann Matthew D.
Published: January 2018

Cancer immunotherapies have revolutionized the treatment of non–small cell lung cancer. Yet, only a small subset of patients will benefit from PD-1 or PD-L1 blockade. PD-L1 tumor cell expression is the only approved biomarker at present. Tumor mutational burden and other emerging biomarkers should improve patient selection. Combination therapy approaches with chemotherapy or cytotoxic T-lymphocyte-associated protein 4 blockade may increase the proportion of patients who benefit from immunotherapy. Although use of immunotherapy in lung cancers with targetable oncogenes has not been particularly successful, the benefit of PD-(L)1 inhibitors in early-stage disease is emerging. This review briefly describes the evolution of the clinical development and future directions of PD-(L)1 blockade in patients with lung cancers.
PD-L1 and Emerging Biomarkers in Immune Checkpoint Blockade Therapy
Authors: Cottrell Tricia R. , Taube Janis M.
Published: January 2018

PD-L1 checkpoint blockade is revolutionizing cancer therapy, and biomarkers capable of predicting which patients are most likely to respond are highly desired. The detection of PD-L1 protein expression by immunohistochemistry can enrich for response to anti–PD-(L)1 blockade in a variety of tumor types, but is not absolute. Limitations of current commercial PD-L1 immunohistochemical (IHC) assays and improvements anticipated in next-generation PD-L1 testing are reviewed. Assessment of tumor-infiltrating lymphocytes in conjunction with PD-L1 testing could improve specificity by distinguishing adaptive (interferon γ driven and cytotoxic T-lymphocyte associated) from constitutive (non–immune mediated) expression. The presence of a high tumor mutational burden also enriches for response to therapy, and early data indicate that this may provide additive predictive value beyond PD-L1 IHC alone. As candidate biomarkers continue to emerge, the pathologist's assessment of the tumor microenvironment on hematoxylin-eosin stain combined with PD-L1 IHC remains a rapid and robust way to evaluate the tumor-immune dynamic.
Is electroweak baryogenesis dead?
Authors: Cline James M.
Published: January 2018

Electroweak baryogenesis is severely challenged in its traditional settings: the minimal supersymmetric standard model, and in more general two Higgs doublet models. Fine tuning of parameters is required, or large couplings leading to a Landau pole at scales just above the new physics introduced. The situation is somewhat better in models with a singlet scalar coupling to the Higgs so as to give a strongly first-order phase transition due to a tree-level barrier, but even in this case no UV complete models had been demonstrated to give successful baryogenesis. Here, we point out some directions that overcome this limitation, by introducing a new source of particle–antiparticle (CP) violation in the couplings of the singlet field. A model of electroweak baryogenesis requiring no fine tuning and consistent to scales far above 1 TeV is demonstrated, in which dark matter plays the leading role in creating a CP asymmetry that is the source of the baryon asymmetry.

This article is part of the Theo Murphy meeting issue ‘Higgs cosmology’.
Asymmetric effects of environmental filtering on the assembly of tropical bird communities along a moisture gradient
Authors: Gomez Juan Pablo , Robinson Scott , Ponciano Jose Miguel
Published: January 2018

The species-sorting hypothesis (SSH) states that environmental factors influence local community assembly of metacommunities by selecting for species that are well adapted to the specific conditions of each site. Along environmental gradients, the strength of selection against individuals that are marginally adapted to the local conditions increases towards the extremes of the environment where the climate becomes harsh. In rainfall gradients, the strength of selection by the environment has been proposed to decrease with rainfall. Under this scenario SSH would predict that immigration of individuals from the metacommunity should be restricted into the dry end of the gradient creating a positive relationship between immigration and rainfall. However, if the selection is strong in both ends of the gradient, the restriction should be expected to be in both directions such that the ends behave as independent metacommunities even in the absence of geographical barriers. In this study we used models based on neutral theory to evaluate if SSH can explain the distribution of bird species along a steep rainfall gradient in Colombia. We found a strong positive relationship between immigration rates and precipitation suggesting that the dry forests impose stronger challenges for marginally adapted bird populations. However, a two-metacommunity model separating dry and wet forests was a better fit to the observed data, suggesting that both extremes impose strong selection against immigrants. The switch from the dry forest to the wet forest metacommunities occurred abruptly over a short geographic distance in the absence of any apparent geographic barrier; this apparent threshold occurs where the forest becomes mostly evergreen. The relative number of rare species in dry forest was lower than in wet forests suggesting that the selection against marginally adapted populations is stronger in the dry forests. Overall, our analyses are consistent with SSH at the regional scales, but the rarity analysis suggests that the mechanisms at the local scales are substantially different. Based on these results, we hypothesize that abiotic (climatic) factors limit immigration into dry forest communities and whereas biotic factors such as competition and predation may limit immigration into bird communities in the wet forest.
Feasibility of clinician-facilitated 3D printing of synthetic cranioplasty flaps
Authors: Panesar Sandip S , Belo Joao Tiago A , D’Souza Rhett N
Published: January 2018

Objectives

3D scanning and stereolithographic printing technology becoming increasingly common, however its implementation into clinical practice is in its primacy. These technologies may be esoteric to the practicing neurosurgeon. We explored a range of 3D scanning and stereolithographic techniques to create patient-specific synthetic implants.

Methods

We simulated bilateral craniectomies from a single cadaveric specimen to create 3 methods of creating stereolithographically-viable virtual models. Firstly, we used ‘pre-and-post operative’ CT derived bony windows to create a virtual skull model, from which the flap was extracted. Secondly, we used an entry-level 3D light-scanner to scan and render models of the individual bone pieces. Thirdly, we used an arm-mounted, 3D laser-scanner to create virtual models using a real-time approach.

Results

Flaps were printed from the CT scanner and laser scanner models only, in a UV-cured polymer. The light scanner did not produce suitable virtual models for printing. The CT scanner derived models required extensive post-fabrication modification to fit the existing defects. The laser-scanner models assumed good fit within the defects without any modification.

Conclusions

The methods presented varying levels of complexity in acquisition and model rendering. Each technique required hardware at varying in price points from $0 to ∼$100,000. The laser-scanner models produced the best quality parts which bore near-perfect fit with the original defects. We discuss potential neurosurgical applications of this technology.
Loss of PRMT5 promotes PDGFRα degradation during oligodendrocyte differentiation and myelination
Authors: Calabretta Sara , Vogel Gillian , Yu Zhenbao , Choquet Karine , Darbelli Lama , Nicholson Thomas B. , Kleinman Claudia L. , Richard Stéphane
Published: January 2018

Platelet derived growth factor receptor α (PDGFRα) signaling is required for proliferation, commitment and maintenance of oligodendrocyte (OL) precursor cells (OPCs). PDGFRα signaling promotes OPC homeostasis and its attenuation signals OPC differentiation and maturation triggering the onset of myelination of the central nervous system (CNS). The initial steps of how PDGFRα signaling is attenuated are still poorly understood. Herein we show that decreased Protein Arginine MethylTransferase5 (PRMT5) expression, as occurs during OPC differentiation, is involved in the down-regulation of PDGFRα by modulating its cell surface bioavailability leading to its degradation in a Cbldependent manner. Mechanistically, loss of arginine methylation at R554 of the PDGFRα intracellular domain reveals a masked Cbl binding site at Y555. Physiologically, depletion of PRMT5 in OPCs results in severe CNS myelination defects. We propose that decreased PRMT5 activity initiates PDGFRα degradation to promote OL differentiation. More broadly, inhibition of PRMT5 may be used therapeutically to manipulate PDGFRα bioavailability.
A conserved mechanism for regulation of endo-lysosomal pH by histone deacetylases
Authors: Prasad Hari , Rao Rajini
Published: January 2018

The pH of the endo-lysosomal system is tightly regulated by a balance of proton pump and leak mechanisms that are critical for storage, recycling, turnover and signaling functions in the cell. Dysregulation of endo-lysosomal pH has been linked to aging, amyloidogenesis, synaptic dysfunction, and various neurodegenerative disorders including Alzheimer’s disease. Therefore, understanding mechanisms that regulate luminal pH may be key to identifying new targets for treatment of these disorders. Meta-analysis of yeast microarray databases revealed that nutrient limiting conditions upregulated transcription of the endosomal Na+/H+exchanger Nhx1 by inhibition of the histone deacetylase (HDAC) Rpd3, resulting in vacuolar alkalinization. Consistent with these findings, Rpd3 inhibition by the HDAC inhibitor and antifungal drug trichostatin A induced Nhx1 expression and vacuolar alkalinization. Bioinformatics analysis of Drosophila and mouse databases revealed that caloric control of Nhx1 orthologs DmNHE3 and NHE6 respectively, was also mediated by histone deacetylases. We show that NHE6 is a target of cAMP-response element-binding (CREB) protein, providing a molecular mechanism for nutrient and HDAC dependent regulation of endosomal pH. Control of NHE6 expression by pharmacological targeting of the CREB pathway can be used to regulate endosomal pH and restore defective amyloid Aβ clearance in an ApoE4 astrocyte model of Alzheimer’s disease. These observations from yeast, fly, mouse and cell culture models reveal an evolutionarily conserved mechanism for regulation of endosomal NHE expression by histone deacetylases and offer new therapeutic strategies for modulation of endo-lysosomal pH in fungal infection and human disease.
Synthesis and structures of six closely related N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]arylamides, together with an isolated reaction intermediate: order versus disorder, molecular conformations and hydrogen bonding in zero, one and two dimensions
Authors: Sagar Belakavadi K. , Yathirajan Hemmige S. , Rathore Ravindranath S. , Glidewell Christopher
Published: January 2018

Six closely related N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]arylamides have been synthesized and structurally characterized, together with a representative reaction intermediate. In each of N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]benzamide, C20H16ClNO2S, (I), N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-4-phenylbenzamide, C26H20ClNO2S, (II), and 2-bromo-N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]benzamide, C20H15BrClNO2S, (III), the molecules are disordered over two sets of atomic sites, with occupancies of 0.894 (8) and 0.106 (8) in (I), 0.832 (5) and 0.168 (5) in (II), and 0.7006 (12) and 0.2994 (12) in (III). In each of N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2-iodobenzamide, C20H15ClINO2S, (IV), and N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2-methoxybenzamide, C21H18ClNO3S, (V), the molecules are fully ordered, but in N-[3-(2-chlorobenzoyl)-5-ethylthiophen-2-yl]-2,6-difluorobenzamide, C20H14ClF2NO2S, (VI), which crystallizes with Z′ = 2 in the space group C2/c, one of the two independent molecules is fully ordered, while the other is disordered over two sets of atomic sites having occupancies of 0.916 (3) and 0.084 (3). All of the molecules in compounds (I)–(VI) exhibit an intramolecular N—H...O hydrogen bond. The molecules of (I) and (VI) are linked by C—H...O hydrogen bonds to form finite zero-dimensional dimers, which are cyclic in (I) and acyclic in (VI), those of (III) are linked by C—H...π(arene) hydrogen bonds to form simple chains, and those of (IV) and (V) are linked into different types of chains of rings, built in each case from a combination of C—H...O and C—H...π(arene) hydrogen bonds. Two C—H...O hydrogen bonds link the molecules of (II) into sheets containing three types of ring. In benzotriazol-1-yl 3,4-dimethoxybenzoate, C15H13N3O4, (VII), the benzoate component is planar and makes a dihedral angle of 84.51 (6)° with the benzotriazole unit. Comparisons are made with related compounds.
Discovering the entrepreneurial endowment of the youth
Authors: Bignotti Alex , le Roux Ingrid
Published: January 2018

Purpose

Entrepreneurship is considered as a possible solution to youth unemployment, and the number of initiatives fostering youth entrepreneurship has multiplied accordingly, also in Africa. However, the effectiveness of such initiatives also lies in whether young people display personality and contextual dimensions conducive to starting and running businesses. The purpose of this paper is to examine the composition of young South Africans’ “entrepreneurial endowment”, represented by personality traits and contextual variables commonly associated with entrepreneurship.

Design/methodology/approach

This paper surveyed secondary students using a questionnaire constructed from validated measurement instruments, obtaining 827 valid responses. It employed exploratory factor analysis to investigate the composition of respondents’ entrepreneurial endowment. It also compared respondents’ entrepreneurial endowment across demographic variables by means oft-tests and ANOVA.

Findings

The results reveal the existence of an entrepreneurial endowment composed of: need for achievement, locus of control, community support, two role models sub-constructs and two family support sub-constructs. Significant differences from the perspective of gender, cultural background and entrepreneurship education also emerged.

Practical implications

The findings confirm that young South Africans have the entrepreneurial endowment needed to be the recipients of entrepreneurship support and highlight relevant differences across demographic variables.

Originality/value

From a theoretical perspective, this paper unveils the structure of young South Africans’ entrepreneurial endowment, composed of four unique dimensions not found in previous research. The insights gained from comparing entrepreneurial endowment results across different groups offer practical implications.
The impact of leverage on discretionary investment: African evidence
Authors: Vengesai Edson , Kwenda Farai
Published: January 2018

Purpose

The purpose of this paper is to explore the impact of leverage on firms’ discretionary investment in Africa.

Design/methodology/approach

The authors employ a dynamic panel data model estimated with generalised method of moments (GMM) estimation techniques on the panel data of listed African non-financial firms. A dynamic model and the generalised methods of moments estimations are handy in controlling for unobserved heterogeneity, endogeneity, autocorrelation, heteroscedasticity, etc.

Findings

In spite of different settings, markets, leverage levels and methodologies, the authors found evidence that leverage constrains investment in African firms. The negative impact is more pronounced in firms with low-growth opportunities than in firms with high-growth opportunities. The results are inclined to the theory that leverage plays a disciplinary role to avoid overinvestment.

Research limitations/implications

African firms’ investment policy does not solely depend on the neoclassical fundamentals determinants of profitability, net worth and cash flows. Financing strategy also has a considerable bearing on the investment policy. The results provide evidence that leverage is a negative externality to the firm’s discretional investment policy for both lowly levered and highly leveraged firms. African firms’ should consider maintaining their low debt levels and rely more on internally generated funds so as not to suppress any available cash flows to interest payments and loan covenants from debt holders.

Originality/value

The study contributes to the literature on investment and financial leverage by the authors providing evidence from Africa, a developing continent, that has not been explored. It shows how conservative leverage levels of African firms, which have been reported to be rising, are impacting on investments. Pertaining to empirical methodology, the authors employ a dynamic panel data model, the GMM estimation technique, which is robust in controlling endogeneity, and a possible bi-directional causality between leverage and investment which have not been used in literature. The study also enables a comparison of the effect of high leverage and low leverage on firm’s discretional investment.
The variations in religious and legal understandings on halal slaughter
Authors: Chandia Mahmood , Soon Jan Mei
Published: January 2018

Purpose

The purpose of this paper is to provide an overview of different understandings regarding the concept of “what constitutes halal” and “who determines this concept?” In practice, this equates to contemporary legal understandings vs religious understandings. The paper further aims to provide an overview of competing Muslim understandings regarding the concept of “What does or does not constitute halal slaughter?” In practice, this equates to evaluating the application of no stunning at all upon an animal (unanimous acceptance) vs the application of reversible stunning upon an animal (contested).

Design/methodology/approach

The study includes a review of prior literature and considers the current scenario of the halal poultry trade and raises important questions regarding Islamic dietary practices, halal food integrity, religious and animal welfare understandings. Three key questions were raised: “To what extent does stunning impact halal slaughter?”; “Who determines what is halal slaughter?”; and “What are the variations and tensions between legal and religious understandings of halal slaughter?”.

Findings

The examination of such requirements and concomitant consumer and provider expectations is underpinned by a study of an operational framework, i.e. industry practices with poultry (hand slaughter, stunning, mechanical slaughter, etc.), ethical values and market forces to appraise whether there is a point of convergence for these that can be beneficial for both seller and consumer concerns. This paper has considered different perspectives on the religious slaughter and provided an overview of competing understandings regarding the above concepts.

Originality/value

This study although academic and philosophical in nature, raises questions on route to suggesting future research directions. It provides real value in stimulating more research in the area of halal food production and contributes to the understanding of different slaughter requirements for religious slaughter and the meat industry. It further sheds light on not only the religious and secular legal frameworks on animal slaughter and welfare but also the variations in understanding between them and provides examples of attempts to bridge any gap. The paper highlights the importance of halal food based on religious values and its implications for wider society.
Stakeholder responses to governmental dietary guidelines
Authors: Bergman Karolin , Persson-Osowski Christine , Eli Karin , Lövestam Elin , Elmståhl Helena , Nowicka Paulina
Published: January 2018

Purpose

The purpose of this paper is to explore how stakeholders in the food and nutrition field construct and conceptualise “appropriate” national dietary advice.

Design/methodology/approach

In total, 40 voluntarily written stakeholder responses to updated official dietary guidelines in Sweden were analysed thematically. The analysis explored the logics and arguments employed by authorities, interest organisations, industry and private stakeholders in attempting to influence the formulation of dietary guidelines.

Findings

Two main themes were identified: the centrality of anchoring advice scientifically and modes of getting the message across to the public. Stakeholders expressed a view of effective health communication as that which is nutritionally and quantitatively oriented and which optimises individuals’ capacities to take action for their own health. Their responses did not offer alternative framings of how healthy eating could be practiced but rather conveyed an understanding of dietary guidelines as documents that provide simplified answers to complex questions.

Practical implications

Policymakers should be aware of industrial actors’ potential vested interests and actively seek out other stakeholders representing communities and citizen interests. The next step should be to question the extent to which it is ethical to publish dietary advice that represents a simplified way of conceptualising behavioural change, and thereby places responsibility for health on the individual.

Originality/value

This research provides a stakeholder perspective on the concept of dietary advice and is among the first to investigate referral responses to dietary guidelines.
A novel and efficient approach to specifying Dirichlet far-field boundary condition of pressure Poisson equation
Authors: Lee Jun-Hyeok , Lee Seung-Jae , Suh Jung-chun
Published: January 2018

Purpose

As the penalized vortex-in-cell (pVIC) method is based on the vorticity-velocity form of the Navier–Stokes equation, the pressure variable is not incorporated in its solution procedure. This is one of the advantages of vorticity-based methods such as pVIC. However, dynamic pressure is an essential flow property in engineering problems. In pVIC, the pressure field can be explicitly evaluated by a pressure Poisson equation (PPE) from the velocity and vorticity solutions. How to specify far-field boundary conditions is then an important numerical issue. Therefore, this paper aims to robustly and accurately determine the boundary conditions for solving the PPE.

Design/methodology/approach

This paper introduces a novel non-iterative method for specifying Dirichlet far-field boundary conditions to solve the PPE in a bounded domain. The pressure field is computed using the velocity and vorticity fields obtained from pVIC, and the solid boundary conditions for pressure are also imposed by a penalization term within the framework of pVIC. The basic idea of our approach is that the pressure at any position can be evaluated from its gradient field in a closed contour because the contour integration for conservative vector fields is path-independent. The proposed approach is validated and assessed by a comparative study.

Findings

This non-iterative method is successfully implemented to the pressure calculation of the benchmark problems in both 2D and 3D. The method is much faster than all the other methods tested without compromising accuracy and enables one to obtain reasonable pressure field even for small computation domains that are used regardless of a source distribution (the right-hand side in the Poisson equation).

Originality/value

The strategy introduced in this paper provides an effective means of specifying Dirichlet boundary conditions at the exterior domain boundaries for the pressure Poisson problems. It is very efficient and robust compared with the conventional methods. The proposed idea can also be adopted in other fields dealing with infinite-domain Poisson problems.
Thermal performance of angled, V-shaped and leaning-V-shaped ribs in a rotating rectangular channel with 45° orientation
Authors: Wang Jinsheng , Luo Lei , Wang Lei , Sunden Bengt Ake , Wang Songtao
Published: January 2018

Purpose

The fluid flow in a rotating channel is obviously different from that in a stationary channel due to the existence of Coriolis force, which, in turn, enhances the heat transfer on the trailing side and reduces the heat transfer on the leading side. The purpose of this paper is to study various rib configurations combined with channel orientation on heat transfer and frictional loss in a rotating channel.

Design/methodology/approach

In the present study, the k-ω SST model was used as the turbulence model. The fluid flow direction in the channel is radially outward. The angle between the rotation axis and leading side is 45°. The channel aspect ratio (W/H) is 2, the blockage ratio (e/Dn ) is 0.1 and the pitch ratio (P/e) is 10. The Reynolds number is fixed at 10,000 and the rotation number varies from 0 to 0.7. Angled ribs, reversed angled ribs, standard V-shaped ribs and outer-leaning V-shaped ribs, are examined.

Findings

It is found that the reversed angled rib configuration and the outer-leaning V-shaped rib configuration display better heat transfer performance than the V-shaped ribs in rotating condition, which is in contrast to stationary condition. At the leading side, the reversed angled rib and the outer-leaning V-shaped rib show better performance in recovering the heat transfer recession due to the negative effects of the Coriolis force.

Research limitations/implications

In the present study, the fluid is incompressible with constant thermophysical properties and the flow is steady.

Practical implications

The results of this study will be helpful in design of ribbed channels internal cooling for turbine blade.

Originality/value

The results imply that the rib configuration combined with channel orientation significantly impacts the heat transfer performance in a rotating channel. The reversed angled rib and the outer-leaning V-shaped rib show better heat transfer performance than standard V-shaped ribs, especially at high Rotating numbers, which is in contrast to stationary condition. The outer-leaning V-shaped rib has a relatively good heat transfer uniformity along the widthwise direction.