bluuebunny/crossref_metadata_2025 huggingface dataset:
A Compact Eulerian Representation of Axisymmetric Inviscid Vortex Sheet Dynamics
Authors: Pesci Adriana I. , Goldstein Raymond E. , Shelley Michael J.
Published: December 2019

A classical problem in fluid mechanics is the motion of an axisymmetric vortex sheet evolving under the action of surface tension, surrounded by an inviscid fluid. Lagrangian descriptions of these dynamics are well‐known, involving complex nonlocal expressions for the radial and longitudinal velocities in terms of elliptic integrals. Here we use these prior results to arrive at a remarkably compact and exact Eulerian evolution equation for the sheet radius r(z, t) in an explicit flux form associated with the conservation of enclosed volume. The flux appears as an integral involving the pairwise mutual induction formula for vortex loop pairs first derived by Helmholtz and Maxwell. We show how the well‐known linear stability results for cylindrical vortex sheets in the presence of surface tension and streaming flows [A. M. Sterling and C. A. Sleicher, J. Fluid Mech. 68, 477 (1975)] can be obtained directly from this formulation. Furthermore, the inviscid limit of the empirical model of Eggers and Dupont [J. Fluid Mech. 262 205 (1994); SIAM J. Appl. Math. 60, 1997 (2000)], which has served as the basis for understanding singularity formation in droplet pinchoff, is derived within the present formalism as the leading‐order term in an asymptotic analysis for long slender axisymmetric vortex sheets and should provide the starting point for a rigorous analysis of singularity formation. © 2019 the Authors. Communications on Pure and Applied Mathematics is published by the Courant Institute of Mathematical Sciences and Wiley Periodicals, Inc.
Active contours with local and global energy based‐on fuzzy clustering and maximum a posterior probability for retinal vessel detection
Authors: Wang Xiancheng , Jiang Zhangwei , Li Wei , Zarei Roozbeh , Huang Guangyan , Ulhaq Anwaar , Yin Xiaoxia , Zhang Bailing , Shi Peng , Guo Mengjiao , He Jing
Published: December 2019

The performance of active contour model is limited on retinal vessel segmentation as vessel images are usually corrupted with intensity inhomogeneity, low contrast, and weak boundary, which severely affect the segmentation results of retinal vessels. A new active contour model combining the local and global information is proposed in this paper to facilitate the vessel segmentation. In our model, the fuzzy conception is firstly introduced as fuzzy methods generally provide more accurate and robust clustering and the concept of fuzziness in fuzzy clustering, which is represented by membership, can reflect the intensity distribution of the image. Then, we define local energy based on Maximum a Posterior Probability and use spatially varying parameters, mean and stand deviation, to describe the local Gaussian distribution in order to better deal with intensity inhomogeneity. Furthermore, we combine local and global energy based on fuzzy clustering, with a weight coefficient. The coefficient is computed by a weight function according to contrast ratio of the image. Experiments on synthetic and real images and comparisons with other state‐of‐the‐art active contour models show that the proposed model can detect objects more accurate and robust, especially for vessels on retinal angiogram.
An availability predictive trust factor‐based semi‐Markov mechanism for effective cluster head selection in wireless sensor networks
Authors: A. Amuthan , A. Arulmurugan
Published: December 2019

The longevity of the sensor networks purely depends on the effectiveness of a cluster head selection process that attributes towards effective network management in wireless sensor networks. However, the majority of the cluster head selection schemes are considered an unrealistic condition which ponders the sensor nodes that have the possibility of being selected as cluster heads are highly energy competitive and trustworthy. In this paper, an availability predictive trust factor‐based semi‐Markov mechanism (APTFSMM) was proposed for facilitating effective cluster head selection with the view to enhance its degree of longevity degree in wireless sensor networks. This proposed APTFSMM inherited the merits of semi‐Markov process for estimating availability predictive trust factor that quantifies the maximum likelihood probability under which it is selected as the cluster head through maximized exploration of multiple transition states of the sensors in the networks. This proposed APTFSMM is determined to be predominant in enhancing the lifetime of the sensor network by 31% with a significantly reduced energy consumption rate of 38% compared with the benchmarked cluster head selection approaches considered for investigation.
Early life stress and development of the endocannabinoid system: A bidirectional process in programming future coping
Authors: Goldstein Ferber Sari , Trezza Viviana , Weller Aron
Published: December 2019

The endocannabinoid system (ECS) critically regulates stress responsivity and emotional behavior throughout development. It regulates anxiety‐like behaviors in humans and animal models. In addition, it is sensitive to early life stress at the gene expression level in a sex‐dependent and region‐dependent manner, and these changes are already evident in the adolescent brain. The ECS modulates the neuroendocrine and behavioral effects of stress, and is also capable of being affected by stress exposure itself. Early life stress interferes with the development of corticolimbic circuits, a major location of endocannabinoid receptors, and increases vulnerability to adult psychopathology. Early life stress alters the ontogeny of the ECS, resulting in a sustained deficit in its function, particularly within the hippocampus. Specifically, exposure to early stress results in bidirectional changes in anandamide and 2‐AG tissue levels within the amygdala and hippocampus and reduces hippocampal endocannabinoid function at puberty. CB1 receptor densities across all brain regions are downregulated later in life following exposure to early life stress. Manipulations affecting the glucocorticoid and the endocannabinoid systems persistently adjust individual emotional responses and synaptic plasticity. This review aims to show the bidirectional trajectories of endocannabinoid modulation of emotionality in reaction to early life stress.
Binding arbitration: Bad for students, bad for schools
Authors: Charmatz Marc
Published: December 2019

Students with disabilities have rights under Title II (state and local colleges and universities) and Title III (private schools) of the Americans with Disabilities Act to file administrative complaints with the United States Department of Justice and to file lawsuits in federal district courts. The ADA also recognizes that there are alternative means of dispute resolution, including “settlement negotiations, conciliation, facilitation, mediation, fact finding mini trials, and arbitration” that are “encouraged to resolve disputes” (42 U.S.C. 12212).
Advocate for universal design across campus
Authors: Hope Joan
Published: December 2019

ORLANDO —The Office of Disability Services can't make campus and courses fully accessible to students with disabilities on its own. A culture that embraces universal design can reduce the need for accommodations and benefits all students, not just those with disabilities.
Seasonal variability of groundwater level effects on the growth of Carex cinerascens in lake wetlands
Authors: Feng Wenjuan , Mariotte Pierre , Xu Ligang , Buttler Alexandre , Bragazza Luca , Jiang Jiahu , Santonja Mathieu
Published: December 2019

Groundwater level is crucial for wetland plant growth and reproduction, but the extent of its effect on plant growth can vary along with changed precipitation and temperature at different seasons. In this context, we investigated the effect of two groundwater levels (10 cm vs. 20 cm depth) on growth and reproductive parameters of Carex cinerascens, a dominant plant species in the Poyang Lake wetland, during three seasons (spring, summer, and autumn) and during two consecutive years (2015 and 2016). Carex cinerascens showed low stem number, height, and individual and population biomass in summer compared to spring and autumn. 10 cm groundwater level was overall more suitable for plant growth resulting in higher stem height and biomass. However, the interactive effect between groundwater level and season clearly demonstrated that the effect of groundwater level on plant growth occurred mainly in autumn. After the withering of the plant population in summer, we observed that C. cinerascens growth recovered in autumn to similar values observed in spring only with 10 cm groundwater level. Consequently, we could deduce that lowering groundwater level in the studied Poyang Lake wetland will negatively impact C. cinerascens regeneration and growth particularly during the second growth cycle occurring in autumn. Additionally, our results showed that, independently of the season and groundwater level, population biomass of C. cinerascens was lower during drier year. Altogether, our findings suggest that water limitation due to both reduction in precipitation and decreased groundwater level during the year can strongly impact plant communities.
Left ventricular outflow tract velocity time integral in hospitalized heart failure with preserved ejection fraction
Authors: Omote Kazunori , Nagai Toshiyuki , Iwano Hiroyuki , Tsujinaga Shingo , Kamiya Kiwamu , Aikawa Tadao , Konishi Takao , Sato Takuma , Kato Yoshiya , Komoriyama Hirokazu , Kobayashi Yuta , Yamamoto Kazuhiro , Yoshikawa Tsutomu , Saito Yoshihiko , Anzai Toshihisa
Published: December 2019

Aims

The prognostic implication of left ventricular outflow tract velocity time integral (LVOT‐VTI) on admission in hospitalized heart failure with preserved ejection fraction (HFpEF) patients has not been determined. We sought to investigate whether LVOT‐VTI on admission is associated with worse clinical outcomes in hospitalized patients with HFpEF.

Methods and results

We studied consecutive 214 hospitalized HFpEF patients who had accessible LVOT‐VTI data on admission, from a prospective HFpEF‐specific multicentre registry. The primary outcome of interest was the composite of all‐cause death and readmission due to heart failure. During a median follow‐up period of 688 (interquartile range 162–810) days, the primary outcome occurred in 83 patients (39%). The optimal cut‐off value of LVOT‐VTI for the primary outcome estimated by receiver operating characteristic analysis was 15.8 cm. Lower LVOT‐VTI was significantly associated with the primary outcome compared with higher LVOT‐VTI (P = 0.005). Multivariable Cox regression analyses revealed that lower LVOT‐VTI was an independent determinant of the primary outcome (hazard ratio 0.94, 95% confidence interval 0.91–0.98). In multivariable linear regression, haemoglobin level was the strongest independent determinant of LVOT‐VTI among clinical parameters (β coefficient = −0.61, P = 0.007). Furthermore, patients with lower LVOT‐VTI and anaemia had the worst clinical outcomes among the groups (P < 0.001).

Conclusions

Lower admission LVOT‐VTI was an independent determinant of worse clinical outcomes in hospitalized HFpEF patients, indicating that LVOT‐VTI on admission might be useful for categorizing a low‐flow HFpEF phenotype and risk stratification in hospitalized HFpEF patients.
Thioether‐Facilitated Iridium‐Catalyzed Hydrosilylation of Steric 1,1‐Disubstituted Olefins
Authors: Zhang Xueyan , Gao Chengpeng , Xie Xingze , Liu Yuanqi , Ding Shengtao
Published: December 2019

One facile and efficient strategy for the hydrosilylation of steric 1,1‐disubstituted terminal alkenes is demonstrated. Investigations on substrate scope and control experiments revealed the necessity of thioether in promoting this process under a simple iridium catalytic system. This convenient and feasible method is expected to be useful in the synthesis of sulfur‐containing organosilicon polymers with different side‐chains.
Consistent floor response spectra for performance‐based seismic design of nonstructural elements
Authors: Merino Roberto J. , Perrone Daniele , Filiatrault Andre
Published: December 2019

The achievement of adequate performance objectives for buildings under increasing seismic intensities is not only related to the performance of structural members but also to the behavior of nonstructural elements. The need to properly design nonstructural elements for earthquakes has been largely demonstrated in the last few years and has become an important objective within the earthquake engineering community. A crucial aspect in the proper design of nonstructural elements is the definition of the seismic demand in terms of both absolute acceleration and relative displacement floor response spectra. In the first part of this study, relative displacement and absolute acceleration floor response spectra were computed for four reinforced concrete moment‐resisting archetype frames via dynamic time‐history analyses and were compared with floor response spectra predicted by means of two recent simplified methodologies available in the literature. It was observed that one of the existing methodologies is generally unable to predict consistent absolute acceleration and relative displacement floor response spectra. An improved procedure is developed for estimating consistent floor response spectra for building structures subjected to low and medium‐high seismic intensities. This new procedure improves the predictions of a relative displacement floor response spectrum by constraining its ordinates at long nonstructural periods to the expected peak absolute displacement of the floor. The resulting acceleration and relative displacement response spectra are then consistently related by the well‐known pseudo‐spectral relationship over the entire nonstructural period range. The effectiveness of the proposed methodology was appraised against floor response spectra computed from nonlinear time‐history analyses.
Evaluating Current Distribution and Influence of Defect Sites for Graphitic Compound Bipolar Plate Materials
Authors: Baumann N. , Blankenship A. , Dorn M. , Cremers C.
Published: December 2019

With the growth in power and size of energy conversion devices, the consideration of current distribution inside cells and stacks becomes increasingly important. In light of understanding the effect of the material properties of graphitic compound materials on current distribution, we developed a novel measurement cell based on a segmented current feed and a segmented measurement board. Using this cell, we determined the cross‐conduction of current in three commercial graphitic compound materials used for the manufacturing of bipolar plates. The conduction behaviors, with respect to compacting pressure as well as total current density, were explained by differences in resistance of conduction pathways. Large observed differences between the materials were discussed in terms of the ratio of through‐plane and in‐plane resistivities. Additionally, we compared several methods to emulate defect sites, in order to evaluate their effect using the novel measurement cell and showed the effect of their size on the current distribution. Finally, we discuss improvements on the measurement setup.
Rational genomic optimization of DNA detection for human papillomavirus type 16 in head and neck squamous cell carcinoma
Authors: Saito Yuki , Favorov Alexander V. , Forman Michael , Ren Shuling , Sakai Akihiro , Fukusumi Takahito , Liu Chao , Sadat Sayed , Ando Mizuo , Xu Guorong , Khan Zubair , Pang John , Valsamakis Alex , Fisch Kathleen M. , Califano Joseph A.
Published: December 2019

Background

We aimed to use genomic data for optimizing polymerase chain reaction (PCR) primer/probe sets for detection of human papillomavirus (HPV)‐16 in body fluids of patients with HPV‐related head and neck squamous cell carcinoma (HPV‐HNSCC).

Methods

We used genomic HPV‐HNSCC sequencing data from a single institutional and a TCGA cohort. Optimized primer/probe sets were designed and tested for analytical performance in CaSki HPV‐16 genome and confirmed in salivary rinse samples from patients with HPV‐HNSCC.

Results

The highest read density was observed between E5 and L2 regions. The E1 region contained a region that was universally present. Among candidate PCR primer/probe sets created, six reliably detected 30 HPV‐16 copy number. In a CLIA certified laboratory setting, the combination of two novel primer/probe with E7 sets improved performance in salivary rinse samples with a sensitivity of 96% and specificity of 100%.

Conclusions

PCR‐based detection of HPV‐16 DNA in HPV‐HNSCC can be improved using rational genomic design.
Knowledge, attitudes, and practices regarding exclusive breastfeeding among HIV‐positive mothers in Uganda: A qualitative study
Authors: Operto Emily
Published: December 2019

Background

In Uganda, the prevalence of human immunodeficiency virus (HIV) in pregnant women was estimated at 6.1% in 2009, and in 2011, mother‐to‐child transmission (MTCT) of HIV resulted in 20 600 new paediatric HIV infections. A total of 50% of MTCT of HIV in Uganda occurs after birth, and this is partially attributable to poor adherence to infant feeding (IF) guidelines. Poor IF practices contribute to approximately 1.4 million deaths in children aged younger than five. In 2011, Uganda's rate of exclusive breastfeeding (EBF) was 62% for infants aged 0 to 5 months. Identifying barriers provides information on how to improve support for HIV‐positive mothers' adherence to EBF, which may take the form of targeted interventions.

Aim

This study explores the knowledge, attitudes, and practices of HIV‐positive mothers in Kampala, Uganda, regarding EBF of infants aged younger than 6 months.

Methods

Five focus group discussions, each consisting of five HIV‐positive mothers, were carried out at Kawempe Home Care using a semi‐structured guide. Thematic content analysis was used to analyse the data.

Results

The study findings showed that the main barriers to HIV‐positive mothers practising EBF include a lack of IF counselling, fear of HIV transmission through breast milk, returning to work, and breastfeeding difficulties. The main factors influencing HIV‐positive mothers' decisions regarding IF are IF counselling and partners' and families' recommendations.

Conclusion

This study recommends increasing access to couples‐based HIV testing at antenatal clinics and couples‐based IF counselling, while ensuring that it addresses breastfeeding difficulties.
Occurrence of Trace Metals in Food Crops Grown on the Mbale Dumpsite, Uganda, and Human Health Risks
Authors: Awino Florence Barbara , Maher William Andrew , Krikowa Frank , Lynch A Jasmyn J
Published: December 2019

Food crops can be used as biomonitors to assess potential public health food safety hazards from contaminated agricultural environments. Globally, more than 800 million people grow fruits, vegetables, and grains on urban garden soils with unknown health risks. This worldwide practice has exposed consumers to pathogenic and carcinogenic risks from locally grown and imported contaminated foodstuffs such as Amaranthus cruentus and Zea mays, traditional and widely consumed crops across the globe. This study used Z. mays and A. cruentus crops to investigate the occurrence and spatial variations of aluminum (Al), chromium (Cr), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations across the Mbale dumpsite, Uganda. Mean concentrations for Fe, Al, Zn, Mn, and Cu were high in both crops, whereas Pb, Cr, Co, Cd, As, Hg, Se, and Ni occurred in trace amounts. Using the 2 crops as biomonitors, significant variations for Al, Zn, Fe, Cr, and Co concentrations in individual crops were identified across the dump center, hill slope, and riverbank. The variations in Al, Zn, Fe, Cr, and Co concentrations were specific for crop types, crop parts, and location. The highest overall accumulation of metals was at the dump center and in crop leaves. Except Pb concentrations in Z. mays seeds, Cr, Pb, Zn, and Al concentrations in other crop parts were above World Health Organization/Food and Agricultural Organization consumer food safety limits. Therefore, Z. mays and A. cruentus consumption could pose health risks to consumers. Further health assessments and potential regulations are recommended to reduce potential health risks from metals in crops for human consumption. Integr Environ Assess Manag 2020;16:362–377. © 2019 SETAC

KEY POINTS

Spatial metal distribution across the Mbale dumpsite zones were assessed using Amaranthus cruentus and Zea mays crops. Al, Zn, Fe, Cr, and Co concentrations in individual crops significantly varied across the three zones. Pb, Cr, Al, and Zn in most crop parts were above the recommended WHO/FAO food safety limits. The highest metal accumulation was at the dump center and in crop leaves.
HPV‐based cervical cancer screening in low‐resource settings: Maximizing the efficiency of community‐based strategies in rural Kenya
Authors: Huchko Megan J. , Olwanda Easter , Choi Yujung , Kahn James G.
Published: December 2019

Objective

To characterize the efficiency of screening through high‐volume community health campaigns (CHCs) by comparing the costs and population reach and identify factors associated with gains in efficiency. Access to effective cervical cancer screening remains limited in low‐resource settings, especially in rural areas. Periodic CHCs are a novel method of offering screening for HPV at lower costs and higher population coverage than health facilities.

Methods

A micro‐costing study was conducted within a cervical cancer screening trial to measure efficiency (cost per woman screened) and population uptake of HPV‐based screening offered through CHCs in Migori County, Kenya between January and September 2016. Regression analysis assessed relationships between population size and efficiency. Structured observations and qualitative interviews identified implementation factors that affected efficiency in individual campaigns.

Results

Communities screening through CHCs had costs per woman screened ranging from US $22.06 to $30.21. Efficiency was directly correlated to overall numbers of women screened, but not to proportion of population screened. Modifiable factors that acted as context‐specific facilitators and barriers with a potential impact on efficiency were identified.

Conclusion

There was substantial variation in efficiency among CHCs. Cultural factors, health beliefs, and poor coordination among implementation partners as potential key barriers to screening uptake were identified.
Strontium‐substituted biphasic calcium phosphate microspheres promoted degradation performance and enhanced bone regeneration
Authors: Chen Ying , Liu Zhongning , Jiang Ting , Zou Xinyu , Lei Lei , Yan Wenjuan , Yang Jingwen , Li Bo
Published: December 2019

Biphasic calcium phosphate (BCP) ceramics are the subject of much attention for use as bone replacement material. However, it remains a challenge to promote the degradation and osteoinductivity performances of BCP ceramics. In this work, novel BCP ceramic microspheres with good degradation and excellent osteoinductivity were prepared through high‐content strontium (Sr) doping. The in vitro results indicated that the Sr10‐BCP, Sr40‐BCP, and Sr80‐BCP microspheres all had their HA crystals partially transformed to the beta tricalcium phosphate phase following high‐temperature sintering because of Ca‐deficient HA formed by the partial substitution of Ca ions by Sr ions. In addition, the degradation rate was increased with the doping of increasing amounts of Sr. All prepared microspheres enhanced human bone marrow‐derived mesenchymal stem cells attachment and proliferation. Specifically, among these modified microspheres, the Sr40‐BCP microspheres showed the highest osteogenic potential. Furthermore, Sr40‐BCP and HA microspheres were implanted in a calvarial defect model of rat to evaluate the in vivo bone augmentation ability. The results indicated that Sr40‐BCP microspheres degraded more completely and significantly promoted new bone regeneration compared with HA microspheres. In conclusion, Sr40‐BCP microspheres have excellent potential for degradation and bone regeneration and are promising osteogenic materials.
An examination of Black women's experiences in undergraduate engineering on a primarily white campus: Considering institutional strategies for change
Authors: Blosser Emily
Published: December 2019

Background

Black women are underrepresented in engineering and face barriers as a result of their race and gender. While existing research often focuses on strategies Black women can adopt to become successful engineers, this study asks how engineering institutions might change to better accommodate Black women.

Purpose

The specific purpose of this study is to explore the following questions: (a) How does the educational environment in engineering marginalize Black women in ways that are beyond their control? (b) How can institutions transform their policies and practices to improve Black women's experiences and participation in engineering?

Design/Method

I conducted interviews with 12 Black women studying engineering at one university. Informed by critical race theory and sociological theories of race, a constructivist grounded theoretical approach was used to identify and refine common themes across interviews.

Results

The findings explore the ways Black women describe their marginalization. Common themes include an acute sense of isolation, grappling with hypervisibility, difficulties forming study groups, and regular exposure to microaggressions.

Conclusions

By drawing attention directly to Black women's stories and experiences, this study offers ways to begin thinking about how institutions can adopt policies to recruit and retain more Black women in engineering. Strategies discussed include promoting new messages of inclusivity in engineering, supporting and creating “counterspaces,” and encouraging engineering educators to create student study groups and recognize microaggressions.
Challenges of HIV diagnosis and management in the context of pre‐exposure prophylaxis (PrEP), post‐exposure prophylaxis (PEP), test and start and acute HIV infection: a scoping review
Authors: Elliott Tamara , Sanders Eduard J , Doherty Meg , Ndung'u Thumbi , Cohen Myron , Patel Pragna , Cairns Gus , Rutstein Sarah E , Ananworanich Jintanat , Brown Colin , Fidler Sarah
Published: December 2019

Introduction

Knowledge of HIV status relies on accurate HIV testing, and is the first step towards access to HIV treatment and prevention programmes. Globally, HIV‐status unawareness represents a significant challenge for achieving zero new HIV infections and deaths. In order to enhance knowledge of HIV status, the World Health Organisation (WHO) recommends a testing strategy that includes the use of HIV‐specific antibody point‐of‐care tests (POCT). These POCTs do not detect acute HIV infection, the stage of disease when viral load is highest but HIV antibodies are undetectable. Complicating things further, in the presence of antiretroviral therapy (ART) for pre‐exposure prophylaxis (PrEP) or post‐exposure prophylaxis (PEP), other currently available testing technologies, such as viral load detection for diagnosis of acute HIV infection, may yield false‐negative results. In this scoping review, we evaluate the evidence and discuss alternative HIV testing algorithms that may mitigate diagnostic dilemmas in the setting of increased utilization of ART for immediate treatment and prevention of HIV infection.

Discussion

Missed acute HIV infection prevents people living with HIV (PLHIV) from accessing early treatment, increases likelihood of onward transmission, and allows for inappropriate initiation or continuation of PrEP, which may result in HIV drug resistance. While immediate ART is recommended for all PLHIV, studies have shown that starting ART in the setting of acute HIV infection may result in a delayed or complete absence of development of HIV‐specific antibodies, posing a diagnostic challenge that is particularly pertinent to resource‐limited, high HIV burden settings where HIV‐antibody POCTs are standard of care. Similarly, ART used as PrEP or PEP may supress HIV RNA viral load, complicating current HIV testing algorithms in resource‐wealthy settings where viral detection is included. As rollout of PrEP continues, HIV testing algorithms may need to be modified.

Conclusions

With increasing use of PrEP and ART in acute infection we anticipate diagnostic challenges using currently available HIV testing strategies. Research and surveillance are needed to determine the most appropriate assays and optimal testing algorithms that are accurate, affordable and sustainable.
HIV‐associated morbidity and mortality in a setting of high ART coverage: prospective surveillance results from a district hospital in Botswana
Authors: Barak Tomer , Neo Dayna T , Tapela Neo , Mophuthegi Patricia , Zash Rebbeca , Kalenga Ketenga , Perry Melissa EO , Malane Mompati , Makhema Joseph , Lockman Shahin , Shapiro Roger
Published: December 2019

Introduction

Antiretroviral therapy (ART) has significantly improved survival in Africa in recent years. In Botswana, where adult HIV prevalence is 21.9%, AIDS‐related mortality is estimated to have declined by 58% between 2005 and 2013 following the initial wide‐spread introduction of ART, and ART coverage has steadily increased reaching 84% in 2016. However, there remains little data about the burden of HIV and its impact on mortality in the hospital setting where most deaths occur. We aimed to describe the burden of HIV and related morbidity and mortality among hospitalized medical patients in a district hospital in southern Botswana in the era of widespread ART coverage.

Methods

We prospectively reviewed medical admissions to Scottish Livingstone Hospital from December 2015 to November 2017 and recorded HIV status, demographics, clinical characteristics and final diagnoses at discharge, death or transfer. We ascertained outcomes and determined factors associated with mortality. Results were compared with similar surveillance data collected at the same facility in 2011 to 2012.

Results

A total of 2316 admissions occurred involving 1969 patients; 42.4% were of HIV‐positive patients, 46.9% of HIV‐negative patients and 10.7% of patients with unknown HIV status. Compared to HIV‐negative patients, HIV‐positive patients had younger age (mean 42 vs. 64 years, p < 0.0001) and higher mortality (22.2% vs. 18.0%, p = 0.03). Tuberculosis was the leading diagnosis among mortality cases in both groups but accounted for a higher proportion of deaths among HIV‐positive admissions (44.5%) compared with HIV‐negative admissions (19.4%, p < 0.0001). Compared with similar surveillance in 2011 to 2012, HIV prevalence was lower (42.4% vs. 47.6%, p < 0.01), and among HIV‐positive admissions: ART coverage was higher (72.2% vs. 56.2%, p < 0.0001), viral load suppression was similar (78.6% vs. 80.3%, p = 0.77), CD4 counts were higher (55.0% vs. 44.6% with CD4 ≥200 cells/mm3, p < 0.001), mortality was similar (22.2 vs. 22.7%, p = 0.93), tuberculosis diagnoses increased (27.5% vs. 20.1%, p < 0.01) and tuberculosis‐associated mortality was higher (35.9% vs. 24.7%, p = 0.05).

Conclusions

Despite high ART‐coverage in Botswana, HIV‐positive patients continue to be disproportionately represented among hospital admissions and deaths. Deaths from tuberculosis may be contributing to lack of reduction in inpatient mortality. Our findings suggest that control of HIV and tuberculosis remain top priorities for reducing inpatient mortality in Botswana.
Dual‐Venc acquisition for 4D flow MRI in aortic stenosis with spiral readouts
Authors: Callahan Sean , Singam Narayana S. , Kendrick Michael , Negahdar MJ , Wang Hui , Stoddard Marcus F. , Amini Amir A.
Published: December 2019

Background

Single Venc 4D flow MRI with Cartesian readout is hampered by poor velocity resolution and noise when imaging during diastole. Dual Venc acquisitions typically require the acquisition of two distinct datasets, which leads to longer scan times.

Purpose/Hypothesis

To design and develop a 4D Spiral Dual Venc sequence. The sequence allows for separate systolic and diastolic Vencs as part of a single acquisition with a prescribed switch time. The implemented sequence was hypothesized to be comparable to Cartesian 4D flow, but with increased velocity resolution in the diastolic phase and with better scan efficiency and reduced noise.

Study Type

Prospective.

Population

The studied populations were two phantoms—a straight pipe with a stenotic narrowing and a phantom of the aortic arch which included a calcific polymeric valve—under both steady and pulsatile flows, six healthy volunteers, and eight patients with severe aortic stenosis (AS).

Field Strength/Sequence

1.5T, Dual Venc 4D flow with spiral readouts.

Assessment

Data from the proposed sequence were compared with data from 4D Cartesian Dual Venc and Single Venc acquisitions. Noise was assessed from the acquired velocity data with the pump turned off and by varying Venc. Steady acquisitions were compared to the proximal slice of the lowest Single Venc acquisition.

Statistical Tests

Steady flows were compared using relative‐root‐mean‐squared‐error (RRMSE). For in vivo flows and pulsatile in vitro flows, net flow for corresponding timepoints were compared with the Pearson correlation test (P < 0.01).

Results

For steady flows, RRMSEs for Single Vencs ranged from 17.6% to 19.4%, and 9.6% to 16.5% for Dual Vencs. The net flow correlation coefficient for the aortic arch phantom was 0.975, and 0.995 for the stenotic phantom. Normal volunteer and patient comparisons yielded a correlation of 0.970 and 0.952, respectively. in vitro and in vivo pulsatile flow waveforms closely matched.

Data Conclusion

The Dual Venc offers improved noise properties and velocity resolution, while the spiral trajectory offers a scan efficient acquisition with short echo time yielding reduced flow artifacts.

Level of Evidence: 2

Technical Efficacy Stage: 1

J. Magn. Reson. Imaging 2020;52:117–128.
Relationship between self‐reported bruxism and periodontal status: Findings from a cross‐sectional study
Authors: Botelho João , Machado Vanessa , Proença Luís , Rua João , Martins Leonardo , Alves Ricardo , Cavacas Maria Alzira , Manfredini Daniele , Mendes José João
Published: December 2019

Background

Several studies seek to prove the relationship between bruxism and periodontal status although it remains unclear and debatable. We aimed to assess the association between self‐reported (SR) bruxism with the periodontal status in a large scale survey.

Methods

A total of 1064 individuals from the southern region of the Lisbon Metropolitan Area (Portugal) were enrolled. Patients were interviewed for the SR bruxism assessment through a self‐report questionnaire. Full‐mouth periodontal status was assessed with probing depth (PD), clinical attachment loss (CAL), gingival recession (REC), and bleeding on probing (BoP) being measured. The American Association of Periodontology/European Federation of Periodontology 2018 case definitions were used. Logistic regression analyses provided information on the influence of SR bruxism towards periodontitis.

Results

SR bruxers exhibited lower prevalence of periodontitis. Additionally, SR bruxers with periodontitis had PD and CAL significantly lower than patients with only periodontitis. Multivariate analysis suggests that SR bruxism was significantly associated with a lower risk of periodontitis (odds ratio [OR] = 0.42 95% CI: 0.32‐0.56). Mean PD and CAL were significantly lower in SR bruxers. When assessing the type of SR bruxism, significant differences among mean PD, CAL, and BoP levels were also identified.

Conclusion

SR bruxism and periodontal status are negatively associated. SR bruxers exhibit lower odds towards periodontitis and better periodontal clinical characteristics. Further studies are mandatory to clarify these findings.
Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy
Authors: Rodríguez‐Zamora P. , Salazar‐Angeles B. , Buendía F. , Cordero‐Silis C. , Fabila J. , Bazán‐Díaz L. , Fernández‐Díaz L.M. , Paz‐Borbón L.O. , Díaz G. , Garzón I.L.
Published: December 2019

Understanding the physical mechanisms of thiolated molecules adsorption on metal surfaces has required copious research, particularly on Au–cysteine systems due to the affinity of sulfur molecules to gold surfaces, as well as the interesting structural modifications that this strong interaction induces and the peculiar optical, chiroptical, and electronic properties of Au(SR) systems. Here, we present vibrational experimental data on the adsorption of L‐ and D‐cysteine on small gold nanoparticles (<2 nm) by means of Raman spectroscopy. L‐ and D‐cysteine molecules adopt the same strained conformation upon adsorption on colloidal gold nanoparticles, regaining structure due to the stabilization that the gold nanoparticle induces on the cysteine, reflected in the recuperation of vibrational bands from their polymorphically distinctive crystalline forms. Through the analysis of Raman vibrational modifications after adsorption, we found experimental evidence that confirms a stabilized cysteine conformation locating the carboxyl group in the antiposition (PC isomeric rotamer) for both molecules. This result is supported by extensive density functional theory (DFT) calculations and simulated Raman spectra, considering zwitterionic cysteine adsorbed on a Au34 cluster, emulating experimental nanoparticle sizes. Our Raman spectroscopy experimental and DFT results determine one of the oxygen atoms of the carboxyl group as a second adsorption site after the sulfur atom, confirming that independent of its polymorphism and enantiomerism, zwitterionic cysteine interacts with gold nanoparticles through the thiol group and the carboxyl group as adsorption sites.
Ten questions to consider when interpreting results of a meta‐epidemiological study—the MetaBLIND study as a case
Authors: Moustgaard Helene , Jones Hayley E , Savović Jelena , Clayton Gemma L , Sterne Jonathan AC , Higgins Julian PT , Hróbjartsson Asbjørn
Published: December 2019

Randomized clinical trials underpin evidence‐based clinical practice, but flaws in their conduct may lead to biased estimates of intervention effects and hence invalid treatment recommendations. The main approach to the empirical study of bias is to collate a number of meta‐analyses and, within each, compare the results of trials with and without a methodological characteristic such as blinding of participants and health professionals. Estimated within‐meta‐analysis differences are combined across meta‐analyses, leading to an estimate of mean bias. Such “meta‐epidemiological” studies are published in increasing numbers and have the potential to inform trial design, assessment of risk of bias, and reporting guidelines. However, their interpretation is complicated by issues of confounding, imprecision, and applicability. We developed a guide for interpreting meta‐epidemiological studies, illustrated using MetaBLIND, a large study on the impact of blinding. Applying generally accepted principles of research methodology to meta‐epidemiology, we framed 10 questions covering the main issues to consider when interpreting results of such studies, including risk of systematic error, risk of random error, issues related to heterogeneity, and theoretical plausibility. We suggest that readers of a meta‐epidemiological study reflect comprehensively on the research question posed in the study, whether an experimental intervention was unequivocally identified for all included trials, the risk of misclassification of the trial characteristic, and the risk of confounding, i.e the adequacy of any adjustment for the likely confounders. We hope that our guide to interpretation of results of meta‐epidemiological studies is helpful for readers of such studies.
Evaluation of accuracy and precision in an amplicon sequencing workflow for marine protist communities
Authors: Catlett Dylan , Matson Paul G. , Carlson Craig A. , Wilbanks Elizabeth G. , Siegel David A. , Iglesias‐Rodriguez M. Debora
Published: December 2019

Advances in high‐throughput DNA sequencing methods reveal the vast diversity of marine protists. Amplicon sequencing of “barcode” genes, such as the 18S small subunit ribosomal RNA gene (henceforth, 18S gene), is a cost‐effective and widely used genetic method for assessing the composition of marine protist communities. This method is now being applied from local to global scales to interrogate the causes and consequences of protist community variations. Significant efforts have been made to validate amplicon methods targeting prokaryotes, but the precision, accuracy, and quantitative potential of 18S gene amplicon sequencing methods for marine protists remain unclear. Here, we use artificial (mock) communities and environmental samples collected from the Santa Barbara Channel, CA to evaluate the precision and accuracy in an amplicon workflow targeting the V9 hypervariable region of the 18S gene for marine protists. Overall, we find that this amplicon workflow has high precision and reasonable accuracy, but the magnitude of analytical uncertainty can increase significantly unless certain procedural issues are avoided. Finally, we demonstrate the value of positive and negative controls in, and the quantitative potential of, amplicon sequencing assessments of marine protist communities.
Synthesis and Characterization of Nickel‐Based Cobalt Ferrite Nanopowder
Authors: Kumari Chanda , Lahiri Preeti
Published: December 2019

In the present investigation, nickel‐substituted cobalt ferrite (Ni0.5Co0.5Fe2O4) nanoparticles are synthesized using chemical co‐precipitation method. Sodium hydroxide (NaOH) base is used as precipitant. The formation of single‐phase cubic structure and the average crystalline sizes are evaluated by X‐ray diffraction technique. The microstructural features is examined by scanning electron microscopy. The high‐ and low‐frequency absorption bands (600–400 cm−1) of Ni0.5Co0.5Fe2O4 are investigated using Fourier‐transform infrared spectroscopy analysis.
Role of Multiferroic Filler on the AC Response of Bi1‐xBaxFeO3 doped PVA:NH4CH3COO Nanocomposite Gel Polymer Electrolytes
Authors: Singh C. P. , Shukla P. K. , Agrawal S. L.
Published: December 2019

The frequency dependent AC conductivity and dielectric studies of multiferroic filler (Bi1‐xBaxFeO3) doped nanocomposite gel polymer electrolyte (NCGPEs) based on PVA:(NH4CH3COO) are investigated in the present work. The nano composite gel polymer electrolyte systems are synthesized for various filler concentrations by solution cast method. The effect of filler concentration on ionic conductivity is studied using AC impedance technique in the frequency range 1–106 Hz. X‐ray diffraction studies reveal the formation of nanocomposite gel polymer electrolyte. The low frequency dispersion in the dielectric response of electrolytes shows the relaxation contribution is superimposed with electrode polarization effects. The relaxation peaks in the NCGPEs are found to shift toward higher frequency side with increasing filler concentration and are suitably correlated to change in morphology of the gel electrolyte system. The variation of AC conductivity with frequency is seen to obey Jonscher's universal power law with the exception of small deviation in the low frequency regime. Modulus formalism of dielectric response suggests that the ion transport is strongly coupled to the polymer segmental motion.
Polyvinylpyrrolidone (PVP) with Ammonium Iodide (NH4I) and 1‐Hexyl‐3‐Methylimidazolium Iodide Ionic Liquid Doped Solid Polymer Electrolyte for Efficient Supercapacitors
Authors: Singh Diksha , Gupta Meenal , Singh Ram Chandra , Pandey Shri Prakash , Karn Rakesh Kumar , Singh Pramod Kumar
Published: December 2019

Ionic liquid‐doped poly(vinylpyrrolidone), ammonium iodide (NH4I) ion conducting polymer electrolytes are prepared by solution cast technique. Ionic liquid (IL), 1‐hexyl‐3‐methylimidazolium (HMImI) is then added to increase the ionic conductivity of polymer electrolytes by reducing the crystallinity of polymer electrolyte. Fourier transform infrared spectroscopy confirms the complex formation as well as composite nature. Polarized optical microscopy affirms the reduction of crystallinity in polymer electrolyte by IL doping. Electrochemical double layer capacitors are then assembled using maximum conducting polymer electrolyte and porous carbon‐based electrodes which shows excellent specific capacitance.
Integrated Therapy for Functional Movement Disorders: Time for a Change
Authors: Lidstone Sarah C. , MacGillivray Lindsey , Lang Anthony E.
Published: December 2019

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A hybrid multi‐attribute decision‐making procedure for ranking project proposals: A historical data perspective
Authors: Oukil Amar , Govindaluri Srikrishna Madhumohan
Published: December 2019

This paper develops a hybrid multiattribute decision‐making methodology for ranking project proposals (PPs) through a judicious usage of historical data of completed projects to determine attribute weights, enabling elimination of problems associated with projected data such as cost and schedule overruns of real‐world projects. The weights generated from data envelopment analysis are explicitly utilized for ranking PPs while allowing subjectivity to be ingeniously incorporated into the decision process. The new approach is implemented for ranking 25 PPs, and the rankings it yields are found indifferent to the decision maker's attitude, which ascertains the robustness of the ranking methodology.
Transcatheter intra‐arterial perfusion (TRIP)‐MRI biomarkers help detect immediate response to irreversible electroporation of rabbit VX2 liver tumor
Authors: Figini Matteo , Zhou Kang , Pan Liang , Sun Chong , Wang Bin , Hu Su , Yang Jia , Shangguan Junjie , Eresen Aydin , Velichko Yury , Yaghmai Vahid , Zhang Zhuoli
Published: December 2019

Purpose

Irreversible electroporation (IRE) is a nonthermal tissue ablation technique that represents a promising treatment option for unresectable liver tumors, but the effectively treated zone cannot be reliably predicted. We investigate the potential benefit of transcatheter intra‐arterial perfusion (TRIP) ‐MRI for the early noninvasive differentiation of IRE zone from surrounding reversibly electroporated (RE) zone.

Methods

Seventeen rabbits with VX2 liver tumors were scanned with morphological and contrast‐enhanced MRI sequences approximately 30 min after IRE tumor ablation. Quantitative TRIP‐MRI perfusion parameters were evaluated in IRE zone and RE zone, defined according to histology. MRI and histology results were compared among zones using Wilcoxon rank‐sum tests and correlations were evaluated by Pearson’s correlation coefficient.

Results

There were significant differences in area under the curve, time to peak, maximum and late enhancement, wash‐in and wash‐out rates in the tumor IRE zones compared with the boundary tumor RE zones and untreated tumors. Histology showed significantly fewer tumor cells, microvessels and significantly more apoptosis in tumor IRE zones compared with tumor RE zones (−51%, −66% and +185%, respectively) and untreated tumors (−60%, −67%, and +228%, respectively). A strong correlation was observed between MRI and histology measurements of IRE zones (r = 0.948) and RE zones (r = 0.951).

Conclusion

TRIP‐MRI demonstrated the potential to detect immediate perfusion changes following IRE liver tumor ablation and effectively differentiate the IRE zone from the surrounding tumor RE zone.