bluuebunny/crossref_metadata_2025 huggingface dataset:
Abnormal digital brachial index prior to hemodialysis access construction and cardiovascular mortality
Authors: Yadav Reshabh , Gerrickens Michael W. M. , Teijink Joep A. W. , Scheltinga Marc R. M.
Published: May 2020

Introduction

An abnormal ankle‐brachial index indicating presence of peripheral arterial disease (PAD) is known to predict mortality in end‐stage renal disease (ESRD). Hand ischemia, reflected by low finger pressures, is also a factor associated with increased mortality in patients undergoing hemodialysis (HD). The Aim of the present study is to determine whether an abnormal digital brachial index in ESRD patients prior to HD access surgery is related to lower survival rates.

Methods

A digital brachial index (DBI, systolic finger pressure/systolic brachial arterial pressure) was obtained using digital plethysmography in ESRD patients before construction of a primary HD access between January 2009 and December 2018 in a single center. Patients were grouped based on categories of DBI (low <80%, normal 80–99%, high ≥100%). Overall and cardiovascular mortality were assessed with the ERA‐EDTA classification system (ERA‐EDTA codes 11, 14‐16, 18, and 22‐26, 29). Factors potentially influencing survival rates were analyzed using standard statistics.

Findings

Follow‐up was available in 199 patients (female n = 80; age 70 years ±12; follow‐up index 99% ±1). Overall, 2 and 4 years survival were similar among DBI groups Moreover, 2 and 4 years freedom from cardiovascular death were also not different (low DBI 80% ±8 and 58% ±11; normal DBI 86% ±4 and 75% ±6; high DBI 74% ±6 and 61% ±7). Following correction for age, diabetes mellitus, cardiovascular disease and smoking, a high DBI conferred a significantly increased risk of cardiovascular mortality (HR 2.09 [1.06–4.13], P = 0.03) and a trend toward higher overall mortality (HR 1.69 [0.98–2.93], P = 0.06).

Discussion

ESRD patients with an abnormally elevated DBI before HD access creation have an increased risk of cardiovascular mortality in the first four postoperative years.
When innovation in education works: stimulating teachers' innovative work behaviour
Authors: Lambriex‐Schmitz Peggy , Van der Klink Marcel R. , Beausaert Simon , Bijker Monique , Segers Mien
Published: May 2020

The twenty‐first century labour market requires employees that proactively shape innovations and solve complex problems. Professionals in the education sector are expected to perform innovative behaviour that not only entails the generation, but also the realization and sustainable implementation of new ideas. In a sample of 458 employees in Dutch secondary and higher vocational education (abbreviated in Dutch to MBO and HBO, respectively), this study investigated the relation between environmental factors (namely task variety, management support and exposure to innovation) and Innovative Work Behaviour (IWB) across the different phases of the innovation process, including a sustainability phase. Results of hierarchical regression analyses showed that management support and exposure to innovations served as a predictor for all phases of IWB. Teachers with supportive managers and a high degree of exposure to innovations showed higher scores on innovative behaviour across all phases. Linear regressions revealed a significant relationship between task variety and IWB. In the hierarchical model, only management suport and exposure to innovations showed significant relations. Background characteristics, such as gender, age, tenure, number of working hours and type of education, for which we controlled during the analyses, played a role in how much IWB is displayed. It can be concluded that a work environment, in which employees are exposed to innovation and are supported is crucial. Additionally, in view of the role background characteristics play, it is recommended to select teachers with specific profiles for the different phases of the innovation process.
Effects of intergroup contact and relative gratification vs. deprivation on prejudice on both sides of the U.S./Mexico status divide
Authors: Eller Anja , Abrams Dominic , Wright Stephen C. , Davies Ben
Published: May 2020

A study in the U.S.–Mexican intergroup context examined how collective relative gratification (RG) versus deprivation affects the relationship between intergroup contact and interpersonal closeness and subtle prejudice towards an out‐group. Participants were Mexican university students in Mexico (N = 239) and non‐Mexican students in California (N = 90). As predicted, Mexicans experienced less gratification/higher relative deprivation (RD), and low quality intergroup contact and expressed lower interpersonal closeness and higher subtle prejudice than U.S. Americans. Differences between countries were larger amongst participants reporting higher RD. Second‐stage moderated mediation analysis showed that the mediating effects of contact between country and interpersonal closeness and subtle prejudice, respectively, were larger amongst participants who felt relatively gratified than those who felt relatively deprived. These findings underline the importance of recognizing the moderating effect of differences in the RG versus RD levels of minority and majority groups when anticipating the potential benefits of intergroup contact for prejudice reduction.
Hypoglycemia unawareness and autonomic dysfunction in diabetes: Lessons learned and roles of diabetes technologies
Authors: Lin Yu Kuei , Fisher Simon J , Pop‐Busui Rodica
Published: May 2020

Impaired awareness of hypoglycemia (IAH) is a reduction in the ability to recognize low blood glucose levels that would otherwise prompt an appropriate corrective therapy. Identified in approximately 25% of patients with type 1 diabetes, IAH has complex pathophysiology, and might lead to serious and potentially lethal consequences in patients with diabetes, particularly in those with more advanced disease and comorbidities. Continuous glucose monitoring systems can provide real‐time glucose information and generate timely alerts on rapidly falling or low blood glucose levels. Given their improvements in accuracy, affordability and integration with insulin pump technology, continuous glucose monitoring systems are emerging as critical tools to help prevent serious hypoglycemia and mitigate its consequences in patients with diabetes. This review discusses the current knowledge on IAH and effective diagnostic methods, the relationship between hypoglycemia and cardiovascular autonomic neuropathy, a practical approach to evaluating cardiovascular autonomic neuropathy for clinicians, and recent evidence from clinical trials assessing the effects of the use of CGM technologies in patients with type 1 diabetes with IAH.
Influence of Preparation Type and Tooth Geometry on the Accuracy of Different Intraoral Scanners
Authors: Ashraf Yasmine , Sabet Ahmed , Hamdy Amina , Ebeid Kamal
Published: May 2020

Purpose

To evaluate the influence of preparation design and tooth geometry on the accuracy of scans obtained from three different intraoral scanners (IOS).

Materials and Methods

Full coverage crown and inlay preparations with known axial wall tapers (6ᵒ and 12ᵒ) were performed on typodont teeth using a computer numerical control machine. Reference models were scanned with a highly accurate reference scanner (Ineos X5) and saved in standard tessellation language (STL) format then each IOS (Omnicam, Trios, and i500) scanned each model 10 times. The STL files obtained from the intraoral scanners were compared to the reference models (trueness) and within each test group (precision). Data were statistically analyzed using three‐ way ANOVA and one‐ way ANOVA.

Results

When comparing trueness values extracoronal preparations (32.30 ± 11.23 µm) was significantly better than intra‐coronal preparation (59.61 ± 16.42 µm). As for opposing wall taper, one‐way ANOVA revealed that the more the convergence or divergence between opposing walls the better is the trueness. Significant differences were observed between the scanners. 3 Shape Trios (35.70 ± 14.12 µm) and medit i500 (44.31 ± 11.41 µm) showed no statistically significant differences. However, both showed significantly better precision results when compared to Omnicam (57.83 ± 22.14 µm).

Conclusion

Extracoronal preparations show better trueness and precision in comparison to intracoronal preparations. Trios and i500 have better trueness and precision than Omnicam. Increasing the taper of the axial wall has a direct effect on trueness of scans obtained from the IOS.
Astragaloside IV ameliorates radiation-induced senescence via antioxidative mechanism
Authors: Liu Xin , Shang Shuying , Chu Weiwei , Ma Liang , Jiang Chenxin , Ding Yanping , Wang Jianlin , Zhang Shengxiang , Shao Baoping
Published: May 2020

Objectives

Ageing is a universal and gradual process of organ deterioration. Radiation induces oxidative stress in cells, which leads to genetic damage and affects cell growth, differentiation and senescence. Astragaloside (AS)-IV has antioxidative, anti-apoptotic and anti-inflammatory properties.

Methods

To study the protective mechanism of AS-IV on radiation-induced brain cell senescence, we constructed a radiation-induced brain cell ageing model, using biochemical indicators, senescence-associated galactosidase (SA-β-gal) senescence staining, flow cytometry and Western blotting to analyse the AS-IV resistance mechanism to radiation-induced brain cell senescence.

Key findings

Radiation reduced superoxide dismutase (SOD) activity and expressions of cyclin-dependent kinase (CDK2), CDK4, cyclin E and transcription factor E2F1 proteins, and increased expressions of p21, p16, cyclin D and retinoblastoma (RB) proteins, malondialdehyde (MDA) activity, SA-β-gal–positive cells and cells stagnating in G1 phase. After treatment with AS-IV, the level of oxidative stress in cells significantly decreased and expression of proteins related to the cell cycle and ageing significantly changed. In addition, SA-β-gal–positive cells and cells arrested in G1 phase were significantly reduced.

Conclusions

These data suggest that AS-IV can antagonize radiation-induced brain cells senescence; and its mechanism may be related to p53-p21 and p16-RB signalling pathways of ageing regulation.
Mechanical and structural properties of leukocyte‐ and platelet‐rich fibrin membranes: An in vitro study on the impact of anticoagulant therapy
Authors: Ockerman Anna , Braem Annabel , EzEldeen Mostafa , Castro Ana , Coucke Birgit , Politis Constantinus , Verhamme Peter , Jacobs Reinhilde , Quirynen Marc
Published: May 2020

Objective and background

Little is known about structural and mechanical properties of leukocyte‐ and platelet‐rich fibrin (L‐PRF) membranes and even less about the influence of antithrombotic drugs on L‐PRF. The aim of this in vitro study is therefore to investigate mechanical properties, fibrin structure and cell content of L‐PRF membranes and the impact of anticoagulant therapy on L‐PRF.

Methods

Blood samples were obtained from 12 volunteers and supplemented with either no, 1.25 IU, 2.5 IU, 5 IU, or 10 IU enoxaparin. L‐PRF membranes were characterized with tensile testing, scanning electron microscopy, and measurement of platelets and leukocytes. Control and enoxaparin‐supplemented L‐PRF membranes were compared.

Results

At 10 IU enoxaparin, no L‐PRF membranes could be generated, whereas the low doses of 1.25 and 2.5 IU had no influence on L‐PRF properties. The mechanical properties, fibrin networks, and number of platelets and leukocytes of 5 IU supplemented membranes were unlike the control membranes, but were not found to be significantly different because of limited sampling and inter‐ and intra‐variability.

Conclusion

Low doses of the anticoagulant enoxaparin do not affect mechanical properties, fibrin network, nor cellular content of L‐PRF, whereas high doses impair L‐PRF generation.
Changes in sleep pattern, sense of time and digital media use during COVID‐19 lockdown in Italy
Authors: Cellini Nicola , Canale Natale , Mioni Giovanna , Costa Sebastiano
Published: May 2020

Italy is one of the major COVID‐19 hotspots. To reduce the spread of the infections and the pressure on Italian healthcare systems, since March 10, 2020, Italy has been under a total lockdown, forcing people into home confinement. Here we present data from 1,310 people living in the Italian territory (Mage = 23.91 ± 3.60 years, 880 females, 501 workers, 809 university students), who completed an online survey from March 24 to March 28, 2020. In the survey, we asked participants to think about their use of digital media before going to bed, their sleep pattern and their subjective experience of time in the previous week (March 17–23, which was the second week of the lockdown) and up to the first week of February (February 3–10, before any restriction in any Italian area). During the lockdown, people increased the usage of digital media near bedtime, but this change did not affect sleep habits. Nevertheless, during home confinement, sleep timing markedly changed, with people going to bed and waking up later, and spending more time in bed, but, paradoxically, also reporting a lower sleep quality. The increase in sleep difficulties was stronger for people with a higher level of depression, anxiety and stress symptomatology, and associated with the feeling of elongation of time. Considering that the lockdown is likely to continue for weeks, research data are urgently needed to support decision making, to build public awareness and to provide timely and supportive psychosocial interventions.
Localisation analysis of nerves in the mouse pancreas reveals the sites of highest nerve density and nociceptive innervation
Authors: Saricaoglu Ömer Cemil , Teller Steffen , Wang Xiaobo , Wang Shenghan , Stupakov Pavel , Heinrich Tobias , Istvanffy Rouzanna , Friess Helmut , Ceyhan Güralp O. , Demir Ihsan Ekin
Published: May 2020

Background

Neuropathy and neuro‐inflammation drive the severe pain and disease progression in human chronic pancreatitis and pancreatic cancer. Mice, especially genetically induced‐mouse models, have been increasingly utilized in mechanistic research on pancreatic neuropathy, but the normal “peripheral neurobiology” of the mouse pancreas has not yet been critically compared to human pancreas.

Methods

We introduced a standardized tissue‐harvesting technique that preserves the anatomic orientation of the mouse pancreas and allows complete sectioning in an anterior to posterior fashion. We applied immunohistochemistry and quantitative colorimetry of all nerves from the whole organ for studying pancreatic neuro‐anatomy.

Key Results

Nerves in the mouse pancreas appeared as “clusters” of nerve trunks in contrast to singly distributed nerve trunks in the human pancreas. Nerve trunks in the mouse pancreas were exclusively found around intrapancreatic blood vessels, and around lymphoid structures. The majority of nerve trunks were located in the pancreatic head (0.15 ± 0.08% of tissue area) and the anterior/front surface of the corpus/body (0.17 ± 0.27%), thus significantly more than in the tail (0.02 ± 0.02%, P = .006). Nerves in the tail included a higher proportion of nociceptive fibers, but the absolute majority, ie, ca. 70%, of all nociceptive fibers, were localized in the head. Mice heterozygous for Bdnf knockout allele (Bdnf+/−) exhibited enrichment of nitrergic nerve fibers specifically in the head and corpus.

Conclusions & Inferences

Neuro‐anatomy of the “mesenteric type” mouse pancreas is highly different from the “compact” human pancreas. Studies that aim at reproducing human pancreatic neuro‐phenomena in mouse models should pay diligent attention to these anatomic differences.
Comparison of treatment effects of different maxillary protraction methods in skeletal class III patients
Authors: Buyukcavus Muhammed Hilmi , Kale Burak , Aydemir Buğra
Published: May 2020

Objective

The aim of this study was to compare treatment outcomes with different maxillary protraction methods in patients with skeletal Class III malocclusion resulting from maxillary retrognathia.

Setting and Sample Population

A total of 55 individuals consisting of 29 females and 26 males with a mean age of 11.4 ± 1.06 years were included in this study.

Material and Methods

Fifty‐five treated maxillary retrognathic patients who underwent different protraction facemask methods were evaluated. Eighteen patients treated with RME were in the first group, and 19 patients treated with a modified Alt‐RAMEC protocol were in the second group; eighteen patients on whom face masks with miniplates were applied were included in the skeletal anchorage (SA) group. Thirty measurements were made on lateral cephalometric radiographs before and after treatment. Differences between the groups were assessed with the ANOVA test.

Results

The mean age was higher in the SA group (11.96 ± 0.92 years) compared with the other groups. The mean ANB angle increased by 2.96°, 4.91° and 3.86° in the RME, Alt‐RAMEC and SA groups, respectively. The forward movement of the maxilla was similar between the groups. However, while the rate of protraction was higher in the modified Alt‐RAMEC group, a greater skeletal effect was found in the SA group.

Conclusion

The most effective method in terms of skeletal effect is the application of the face mask with skeletal anchorage; the modified Alt‐RAMEC protocol can be applied before face mask to obtain faster protraction.
De Se Attitudes and Computation
Authors: Hamilton Fairley Neil
Published: May 2020

There has been debate between those who maintain that indexical expressions are not essential and those who maintain that such indexicals cannot be dispensed with without an important loss of content. This version of the essentialist view holds that thoughts must also have indexical elements. Indexical thoughts appear to be in tension with the computational theory of mind (CTM). In this case we have the following inconsistent triad:

(i) De se thoughts are essential.

(ii) De se thoughts are indexical, they have a (Kaplanian) character.

(iii) Computations can only take the syntactic type into account, they cannot take tokens into account.

If (iii) is correct, then it seems we cannot make sense of a thought which uses a character such that its referent could vary from tokening to tokening. I argue that (iii) need not cause a problem, while maintaining the CTM. I claim that computations need not be sensitive to the features of a tokened symbol in the way that character demands. This job may be performed by a non‐modular part of the mind. Resolving the triad in this way provides a reason to accept that indexicals in thought are possible.
Estimating retention in HIV care accounting for clinic transfers using electronic medical records: evidence from a large antiretroviral treatment programme in the Western Cape, South Africa
Authors: Bengtson Angela M. , Colvin Christopher , Kirwa Kipruto , Cornell Morna , Lurie Mark N.
Published: May 2020

Background

Estimates of retention in antiretroviral treatment (ART) programmes may be biased if patients who transfer to healthcare clinics are misclassified as lost to follow‐up (LTFU) at their original clinic. In a large cohort, we estimated retention in care accounting for patient transfers using medical records.

Methods

Using linked electronic medical records, we followed adults living with HIV (PLWH) in Cape Town, South Africa from ART initiation (2012‐2016) through database closure at 36 months or 30 June 2016, whichever came first. Retention was defined as alive and with a healthcare visit in the 180 days between database closure and administrative censoring on 31 December 2016. Participants who died or did not have a healthcare visit in > 180 days were censored at their last healthcare visit. We estimated the cumulative incidence of retention using Kaplan–Meier methods considering (i) only records from a participant’s ART initiation clinic (not accounting for transfers) and (ii) all records (accounting for transfers), over time and by gender. We estimated risk differences and bootstrapped 95% confidence intervals to quantify misclassification in retention estimates due to patient transfers.

Results

We included 3406 PLWH initiating ART. Retention through 36 months on ART rose from 45.4% (95% CI 43.6%, 47.2%) to 54.3% (95% CI 52.4%, 56.1%) after accounting for patient transfers. Overall, 8.9% (95% CI 8.1%, 9.7%) of participants were misclassified as LTFU due to patient transfers.

Conclusions

Patient transfers can appreciably bias estimates of retention in HIV care. Electronic medical records can help quantify patient transfers and improve retention estimates.
Short‐term very low caloric intake causes endothelial dysfunction and increased susceptibility to cardiac arrhythmias and pathology in male rats
Authors: Almeida Jônathas F. Q. , Shults Nataliia , de Souza Aline M. A. , Ji Hong , Wu Xie , Woods James , Sandberg Kathryn
Published: May 2020

New Findings

What is the central question of this study?

What are the effects of a 2 week period of severe food restriction on vascular reactivity of resistance arteries and on cardiac structure and function?

What is the main finding and its importance?

This study showed, for the first time, that a 2 week period of severe food restriction in adult male Fischer rats caused endothelial dysfunction in mesenteric arteries and increased the susceptibility to ischaemia–reperfusion‐induced arrhythmias and cardiac pathology. Our findings might have ramifications for cardiovascular risk in people who experience periods of inadequate caloric intake.

Severe food restriction (sFR) is a common dieting strategy for rapid weight loss. Male Fischer rats were maintained on a control (CT) or sFR (40% of CT food intake) diet for 14 days to mimic low‐calorie crash diets. The sFR diet reduced body weight by 16%. Haematocrits were elevated by 10% in the sFR rats, which was consistent with the reduced plasma volume. Mesenteric arteries from sFR rats had increased sensitivity to vasoconstrictors, including angiotensin II [maximum (%): CT, 1.30 ± 0.46 versus sFR, 11.5 ± 1.6; P < 0.0001; n = 7] and phenylephrine [maximum (%): CT, 78.5 ± 2.8 versus sFR, 94.5 ± 1.7; P < 0.001; n = 7] and reduced sensitivity to the vasodilator acetylcholine [EC50 (nm): CT, 49.2 ± 5.2 versus sFR, 71.6 ± 6.8; P < 0.05; n = 7]. Isolated hearts from sFR rats had a 1.7‐fold increase in the rate of cardiac arrhythmias in response to ischaemia–reperfusion and more cardiac pathology, including myofibrillar disarray with contractions and cardiomyocyte lysis, than hearts from CT rats. The sFR dietary regimen is similar to very low‐calorie commercial and self‐help weight‐loss programmes, which provide ∼800–1000 kcal day−1. Therefore, these findings in rats warrant the study of cardiovascular function in individuals who engage in extreme dieting or are subjected to bouts of very low caloric intake for other reasons, such as socioeconomic factors and natural disasters.
Relación entre la enfermedad periodontal y la enfermedad pulmonar obstructiva crónica: revisión de la literatura
Authors: Moreno Correa Sandra Milena , Bolaños Andrés Felipe , Jaramillo Juan José , Jimenez Alexandra , Moreno Freddy
Published: May 2020

Introducción: La enfermedad periodontal afecta los tejidos de soporte del diente generando una manifestación inflamatoria crónica desencadenada principalmente por bacterias incluidas en la biopelícula oral, las cuales pueden migrar a otros tejidos del cuerpo, siendo las vías respiratorias un blanco susceptible. Objetivo: Establecer si existe relación entre la enfermedad periodontal y la EPOC según lo reportado en la literatura en los últimos 20 años. Materiales y métodos: Se realizó una búsqueda sistemática de la literatura en el Medline (a través del motor de búsqueda PubMed) mediante las pautas de la declaración PRISMA con ayuda de los descriptores en salud tipo MeSh “periodontitis”, “chronic obstructive pulmonary disease”, “inflammation” y “bacteremia”. Resultados: Se revisaron 49 publicaciones entre 1998 y 2018.  El mayor número corresponden al año 2013. El tipo de publicación más frecuente fueron los estudios de tipo descriptivo (41%), seguido por casos y controles (29%), revisiones de la literatura (18%), estudios de cohorte retrospectivos (10%) y metaanálisis (2%). Del total de publicaciones, el 94% reportan que si existe relación entre la EP y EPOC mientras que el 6% niegan dicha asociación. Conclusión: Se encuentra asociación entre las dos enfermedades, aunque la evidencia es insuficiente para establecer una relación causa-efecto, se puede sugerir que la enfermedad periodontal es un indicador de riesgo para EPOC y viceversa, ya que se sugiere una relación de doble vía.
Innovación en las unidades de urgencias
Authors: Carrillo Atilio Moreno
Published: May 2020

La humanidad siempre ha estado ligada a la innovación, son numerosos los ejemplos que han marcado el curso de la historia. El área de la salud no ha sido ajena a los beneficios de la innovación en su desarrollo, en las últimas décadas se han evidenciado grandes avances y aportes en los procesos diagnósticos, terapéuticos y de rehabilitación de diversas enfermedades. La innovación en el sector de la salud debe ser un proceso de creación de valor para el individuo, la sociedad y las empresas que busque la introducción de nuevos bienes o servicios, procesos de atención o producción y modelos de negocio y organizativos para mejorar la eficiencia y la competitividad de las organizaciones, obtener beneficios sociales y generar beneficios económicos. Son múltiples los retos que se presentan día a día en el proceso de atención de las unidades de urgencias que podrían ser abordados a través de soluciones innovadoras, por medio de la realización de acciones por fuera de los estándares tradicionales. Este artículo reflexiona en torno a la justificación y el propósito de la innovación en las unidades de urgencias y aborda estrategias y herramientas que se pueden utilizar para que la innovación se consolide y funcione.
Synthesis, Characterization, and Photovoltaic Performance of CdO-Based Nano Hybrid Material in Solid-State Dye-Sensitized Solar Cells
Authors: Batool Arifa , Shah Syed Mujtaba , Ullah Naimat , Hussain Hazrat
Published: May 2020

Cadmium oxide nanoparticles (NPs) were successfully synthesized through the simple and low-cost sol–gel method. The optical, morphological, compositional, and structural properties of as-synthesized NPs were investigated by ultraviolet–visible (UV/Vis) spectroscopy, fluorescence spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. Absorption spectra of CdO NPs were used for band gaps calculation, which was found to be 2.11 eV. The XRD pattern was used to investigate the purity and crystalline nature of NPs. Morphology and elemental composition were investigated by using SEM and energy-dispersive X-ray spectroscopy (EDX), respectively. FTIR assisted in identifying the functional groups and grafting of the dye on the surface of NPs. These CdO nanoparticles were photosensitized with Ru (II) based Z907 dye. Z907 dye was employed to extend the absorption spectrum of the material to the visible region of the solar spectrum so as to harvest the maximum amount of solar influx on the surface of earth. The energy level diagram revealed that the interaction among the constituents of the nanohybrid assembly permitted the flow of the electron in a cascade manner from dye to CdO nanoparticles. The synthesized photoactive nanohybrid material was thoroughly blended with poly (3-hexylthiophene), a solid electrolyte, and I–V measurements under simulated radiations 1000 W/m2 (AM 1.5) were recorded. A maximum induced photon to the current conversion efficiency of 0.60% was achieved.
Techno-Economic Evaluation of a Concentrating Solar Power Plant Driven by an Organic Rankine Cycle
Authors: El hamdani Fayrouz , Vaudreuil Sébastien , Abderafi Souad , Bounahmidi Tijani
Published: May 2020

Concentrating solar power (CSP) technology is one of the promising options to generate green energy. However, the cost of kWhe produced is relatively high compared with fossil resources and can be reduced by integrating a cogeneration system exploiting waste energy. In this study, a technico-economic evaluation of a 1 MWe CSP plant with a condensation heat (85 °C) is investigated. The temperature constraint is set to meet the thermal separation needs of the draw solution of a forward osmosis desalination process. The purpose of this study focuses on the factors involved in reducing the cost per kWhe, which are the selection of the organic fluid used in the organic Rankine cycle and the appropriate choice of the solar multiple (SM) according to the appropriate storage hours (SH) maximizing the CSP thermal efficiency. The performance of different organic fluids was compared, based on the calculation of the thermodynamic cycle efficiency. The cyclopentane was retained for its reduced cost. Operating with this fluid, a sensitivity analysis was realized to test the effect of the solar multiple and storage hours on the power plant. It allows us to conclude that different appropriate combination between storage hours and solar multiple can be chosen, for the needs of our project, we opt for 8 h and 1.85, respectively. Thus, in this case, the cost of kWh was found to be 23.95¢.
Comparative Thermal Performance Analysis on Helical Screw Insert in Tube With Number of Strips With Nanofluid at Laminar Flow Regime
Authors: Chaurasia Shashank Ranjan , Sarviya R. M.
Published: May 2020

The experimental analysis is arranged to evaluate the thermal hydraulic performance on nanofluid flow in helical screw insert with tube at a number of strips and different twist ratios in laminar flow regime. The single strip (SS) helical screw inserts are also compared with the double strip (DS) helical screw inserts. The heat transfer enhancement is achieved with nanofluid flow in double strip as compared with single strip helical screw insert at decreased values of twist ratio and increased values of Reynolds number. A maximum enhancement of 421% is found in the value of Nusselt number with double strip helical screw insert at twist ratio of 1.5 and low value of Reynolds number in the flow of nanofluid than water in plain tube. The common correlations of Nusselt number and friction factor are generated. The thermal performance factor (TPF) is achieved at a maximum value of 2.42 with double strip than single strip helical screw inserts at twist ratio of 2.5 and low value of Reynolds number. The present analysis shows suitability of the double strip helical screw insert to enable miniaturization of the heat exchangers. A compact heat exchanger decreases the size of thermal application such as solar water heater, solar power plants, electronic cooling systems, radiator, etc., which could save environment by pollution reduction with utilization of energy.
Gap Test of Crack-Parallel Stress Effect on Quasibrittle Fracture and Its Consequences
Authors: Nguyen Hoang Thai , Pathirage Madura , Cusatis Gianluca , Bažant Zdeněk P.
Published: May 2020

In the standard fracture test specimens, the crack-parallel normal stress is negligible. However, its effect can be strong, as revealed by a new type of experiment, briefly named the gap test. It consists of a simple modification of the standard three-point-bend test whose main idea is to use plastic pads with a near-perfect yield plateau to generate a constant crack-parallel compression and install the end supports with a gap that closes only when the pads yield. This way, the test beam transits from one statically determinate loading configuration to another, making evaluation unambiguous. For concrete, the gap test showed that moderate crack-parallel compressive stress can increase up to 1.8 times the Mode I (opening) fracture energy of concrete, and reduce it to almost zero on approach to the compressive stress limit. To model it, the fracture process zone must be characterized tensorially. We use computer simulations with crack-band microplane model, considering both in-plane and out-of-plane crack-parallel stresses for plain and fiber-reinforced concretes, and anisotropic shale. The results have broad implications for all quasibrittle materials, including shale, fiber composites, coarse ceramics, sea ice, foams, and fone. Except for negligible crack-parallel stress, the line crack models are shown to be inapplicable. Nevertheless, as an approximation ignoring stress tensor history, the crack-parallel stress effect may be introduced parametrically, by a formula. Finally we show that the standard tensorial strength models such as Drucker–Prager cannot reproduce these effects realistically.
Influence of precursor dose and residence time on the growth rate and uniformity of vanadium dioxide thin films by atomic layer deposition
Authors: Niang Kham M. , Bai Guandong , Robertson John
Published: May 2020

The growth of vanadium dioxide (VO2) thin films using tetrakis (ethyl-methyl) amino vanadium (TEMAV) and H2O by atomic layer deposition (ALD) has been investigated as a function of the exposure dose and residence time. A novel multiple pulse mode has been employed to mitigate the small deposition rate brought about by the low vapor pressure of TEMAV. Compared to the conventional ALD cycle with a single pulse of precursor, the use of multiple pulsing with very short pulse time allows lower consumption of precursor, but larger exposure dose and longer residence time on the growth surface, resulting in a higher growth rate for a low volatility precursor, while maintaining a good film uniformity across 4-in. wafers. The Raman analysis and the electrical resistivity modulation of the VO2 thin films show that the films synthesized by the multiple pulse mode is comparable to the films synthesized by the conventional single pulse mode.
Why Are There So Few Women in Physics? Reflections on the Experiences of Two Women
Authors: Doucette Danny , Singh Chandralekha
Published: May 2020

Some of the reasons for the underrepresentation of women in physics are evident in the reflections of two undergraduate women. Leia is a chemistry major who loves college-level physical chemistry and quantum mechanics but does not identify with the discipline of physics, partly because she has low self-efficacy as a physicist and has received very little recognition for her work and learning in physics. Paulette is a physics major who loves physics but feels isolated by the current physics learning environment. She reluctantly dropped an honors introductory lab after being snubbed by her male classmates, who partnered with one another, leaving her to work alone. Paulette’s experiences with condescending male professors activated a stereotype threat about who can succeed in physics that caused her to disengage in class. In addition to these things, in this paper we discuss what these women felt has helped them so far and explore their suggestions for what would help women in physics courses as they pursue their quest for a physical science degree.
Supporting Inclusive Teaching in Introductory College Physics
Authors: Getty Stephen , Gosnell Natalie , Whitten Barbara , Taylor Joseph
Published: May 2020

Even among the sciences, physics stands out as an unusually White- and male-dominated field. The American Institute of Physics (AIP) reports that only 19% of physics faculty are women, and less than 6% of physics faculty are African American or Hispanic. Particularly for female students, the transition from high school to a college major in physics has been identified as the most important point of attrition. As such, undergraduate physics education is a critical juncture where these trends can be interrupted. We approached this problem by using teaching strategies intended to promote inclusiveness in a calculus-based, introductory college physics course, a key requirement in many STEM majors and a gateway to the undergraduate physics major. Proponents of inclusive teaching strategies argue that using such strategies will benefit all students, particularly those from marginalized groups, increase the diversity of physics majors, and ultimately contribute to a more diverse community of physicists.
Networks of Support: Investigating a Counterspace that Provides Identity Resources for Minoritized Students in Post-Secondary Physics
Authors: Gonsalves Allison J. , Chestnutt Hannah R.
Published: May 2020

There is recent evidence suggesting that formal and informal support networks for minoritized students in science, technology, engineering, and mathematics (STEM) can contribute to their persistence in the field. These counterspaces can serve as “safe spaces” where deficit notions of minoritized students can be challenged and where a positive collegiate climate can be established. Generally, counterspaces are found outside of STEM departments: with mentors, in campus student groups, or in conferences focused on diversity in STEM. However, two participants in a study by Johnson and colleagues reported evidence suggesting that physics departments themselves can act as counterspaces. We are inspired by this finding to investigate the role that a network of support for minoritized students in a physics department of an Eastern Canadian university has on female students’ experiences in their physics program. In this paper, we present data suggesting that participation in this network can promote forms of participation that may be especially beneficial for minoritized students in physics. We argue that this network acts as a counterspace built into the structure of a university physics department. Furthermore, we suggest that access to counterspaces such as this one may be able to provide identity resources that minoritized students draw on to position themselves as insiders when entering physics programs.
Lessons from Research Exploring the Underrepresentation of Women in Physics
Authors: Gosling Chris , Gonsalves Allison J.
Published: May 2020

Despite decades of research into the gender disparity in physics education and physics practice, the underrepresentation of women in physics persists today. In physics education research, this gender disparity has been constructed as problematic, and numerous approaches from a variety of perspectives have been taken to both research and address it. In this paper, we explore the framings that have been used to motivate study of the underrepresentation of women in physics and the implications these framings have for introductory physics educators. We wish to acknowledge in the framing of this paper that the use of the term “underrepresentation” has prompted a specific characterization of the issues women face in physics (one of low numbers) and the responses (attempts to increase numbers). As its use is pervasive in the research into sex, gender, and physics, we continue here with the term underrepresentation, but suggest that “minoritization” might more appropriately signal the history of structural and institutional actions in physics cultures that have limited access for White and racialized women.
Changing Culture and Climate to Prevent Sexual Harassment in the Physics Educational Setting
Authors: Knaub Alexis V. , Maier Steven J. , Ding Lin
Published: May 2020

The issue of sexual harassment in science is gaining much needed attention. In physics, a 2019 survey study found that 68% of female undergraduate respondents experienced sexual or sexist harassment in a physics environment. In 2018, the National Academy of Science released a report to address the prevalence of sexual harassment in sciences, engineering, and medicine. The report notes anyone can experience sexual harassment, but some demographics (e.g., women; lesbian, gay, bisexual, transgender, queer [LGBTQ+)] individuals) may have higher rates, including those with multiple minoritized identities. While there are many important aspects to address regarding sexual harassment, in this article we focus on the third recommendation in the National Academies’ report: “Move beyond legal compliance to address culture and climate.” In the sections below, we discuss some of the limitations of policy and provide suggestions for how to create a culture and climate in the physics classroom and around the department that can work to prevent sexual harassment. We draw from research on sexual harassment from a variety of contexts, including outside of academia and STEM, as there are likely commonalities in experiences regardless of context.
The Search for Exoplanets: A Capstone Project in Service Learning and Outreach
Authors: Archer Avery , Sederberg David , Kondapaneni Guna , Sands Philip
Published: May 2020

The Search for Exoplanets is an interactive computer simulation, the product of a collaboration between the Departments of Physics and Astronomy and Computer Science at Purdue University. Our goal was to create a computer simulation that would introduce students to scientific principles, research methodology, and analysis of data with which planets in another solar systems are discovered and characterized. We sought to create a simulation that would be engaging, realistic, an accurate model of research, and appropriate to the level of knowledge and abilities for a monthly outreach program, Saturday Morning Astrophysics at Purdue.
Targeting pulmonary tumor microenvironment with CXCR4-inhibiting nanocomplex to enhance anti–PD-L1 immunotherapy
Authors: Li Zhaoting , Wang Yixin , Shen Yuexin , Qian Chenggen , Oupicky David , Sun Minjie
Published: May 2020

CXCR4 antagonistic nanocomplex regulates the immune process to enhance anti–PD-L1 immunotherapy.
Deep long-period earthquakes generated by second boiling beneath Mauna Kea volcano
Authors: Wech Aaron G. , Thelen Weston A. , Thomas Amanda M.
Published: May 2020

Rumblings of a dormant volcano

Earthquakes near volcanoes are often a warning sign of a future eruption. However, deep long-period earthquakes (DLPs) are a special type of seismicity tied most often to quiescent volcanoes. Wech
et al.
found more than a million of these DLPs under the inactive Mauna Kea volcano in Hawai'i over the past 19 years (see the Perspective by Matoza). Analysis of this large number of observations allowed the authors to conclude that the DLPs were connected to a deep, cooling magma body. Deep gas releases triggered by minerals crystallizing in the deep magma through the “second boiling” process may open cracks, triggering the DLPs.

Science
, this issue p.
775
; see also p.
708
Early precursors and molecular determinants of tissue-resident memory CD8
+
T lymphocytes revealed by single-cell RNA sequencing
Authors: Kurd Nadia S. , He Zhaoren , Louis Tiani L. , Milner J. Justin , Omilusik Kyla D. , Jin Wenhao , Tsai Matthew S. , Widjaja Christella E. , Kanbar Jad N. , Olvera Jocelyn G. , Tysl Tiffani , Quezada Lauren K. , Boland Brigid S. , Huang Wendy J. , Murre Cornelis , Goldrath Ananda W. , Yeo Gene W. , Chang John T.
Published: May 2020

Heterogeneity of small intestine intraepithelial CD8
+
T cells suggests functionally distinct subsets of T
RM
cells and their precursors.
Comparative Analysis of the Euroimmun CXCL13 Enzyme-Linked Immunosorbent Assay and the ReaScan Lateral Flow Immunoassay for Diagnosis of Lyme Neuroborreliosis
Authors: Ziegler Katharina , Rath Anca , Schoerner Christoph , Meyer Renate , Bertsch Thomas , Erbguth Frank , Bogdan Christian , Steinmann Jörg , Held Jürgen
Published: May 2020

Diagnosis of Lyme neuroborreliosis (LNB) is challenging, as long as
Borrelia
-specific intrathecal antibodies are not yet detectable. The chemokine CXCL13 is elevated in the cerebrospinal fluid (CSF) of LNB patients. Here, we compared the performances of the Euroimmun CXCL13 enzyme-linked immunosorbent assay (CXCL13 ELISA) and the ReaScan CXCL13 lateral flow immunoassay (CXCL13 LFA), a rapid point-of-care test, to support the diagnosis of LNB. In a dual-center case-control study, CSF samples from 90 patients (34 with definite LNB, 10 with possible LNB, and 46 with other central nervous system [CNS] diseases [non-LNB group]) were analyzed with the CXCL13 ELISA and the CXCL13 LFA.
Impact of Rapid Antimicrobial Susceptibility Testing in Gram-Negative Rod Bacteremia: a Quasi-experimental Study
Authors: Hogan Catherine Anne , Ebunji Bertrand , Watz Nancy , Kapphahn Kristopher , Rigdon Joseph , Mui Emily , Meng Lina , Alegria William , Holubar Marisa , Deresinski Stanley , Banaei Niaz
Published: May 2020

Clinical justification for rapid antimicrobial susceptibility testing (AST) in Gram-negative rod (GNR) bacteremia is compelling; however, evidence supporting its value is sparse. We investigated the impact of rapid AST on clinical and antimicrobial stewardship outcomes in real-world practice. We performed a before-and-after quasi-experimental study from February 2018 to July 2019 at a tertiary hospital of the 24-h/day, 7-day/week implementation of the direct Vitek 2 AST method from positive blood culture broth for GNR bacteremia with electronic isolate-specific de-escalation comments and daytime antibiotic stewardship program (ASP) intervention.
Major Capsid Protein Synthesis from the Genomic RNA of Feline Calicivirus
Authors: Urban Christian , Luttermann Christine
Published: May 2020

Caliciviruses are a cause of important diseases in humans and animals. It is crucial to understand the prerequisites of efficient replication of these viruses in order to develop strategies for prevention and treatment of these diseases. It was shown before that all caliciviruses except vesiviruses have established mechanisms to achieve major capsid protein (VP1) translation from the genomic RNA. Here, we show for the first time that a member of the genus
Vesivirus
also has a translation initiation mechanism by which a precursor protein of the VP1 protein is expressed from the genomic RNA. This finding clearly points at a functional role of the calicivirus VP1 capsid protein in early replication, and we provide experimental data supporting this hypothesis.
Treatment of infants with craniofacial malformations
Authors: Wiechers Cornelia , Thjen Tabea , Koos Bernd , Reinert Siegmar , Poets Christian F
Published: May 2020

Infants with craniofacial malformations (CFMs) are at increased risk of various clinical problems, including respiratory and feeding disorders, the result of which may be long-lasting. An improvement in clinical care can be achieved by prenatal diagnosis and interdisciplinary birth preparation. Feeding problems may particularly be stressful for the family and require a team approach involving nursing staff, speech therapists and nutritional specialists to anticipate, avoid and treat sequelae such as failure to thrive or recurrent aspirations. Special techniques (eg, optimisation of breast feeding, alternative feeding methods or manual orofacial therapy) may be used individually to improve feeding competence; supplemental nutrition via a nasogastric or gastrostomy tube may be temporarily necessary to ensure adequate weight gain. The high prevalence of respiratory disorders in infants with craniofacial abnormalities requires anticipation and screening to prevent growth failure and neurological deficits. Treatment of upper airway obstruction varies widely, strategies can be divided into non-surgical and surgical, and in those aimed at widening the pharyngeal space (eg, prone position, palatal plates, craniofacial surgery) and those bridging the narrow upper airway (eg, nasopharyngeal airway, modified palatal plate, pneumatic airway stenting, tracheostomy). The complex management of an infant with CFM should be performed by a multidisciplinary team to offer specialised support and care for affected families.