bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of The Dissolution Method With N, N-Dimethylformamide As A Solvent On The Electrical Properties Of Acrylonitrile Butadiene Styrene And Carbon Nanotube Composites
Authors: Pettit Estell Bryce M. , Gerhardt Rosario A.
Published: June 2020

The objective of this study is to create electrically conducting composite polymers using the dissolution method. Composites are made from Acrylonitrile Butadiene Styrene (ABS) as the matrix and Carbon Nanotubes (CNTs) as the filler. Composites were made using the dissolution method with N, N-Dimethylformamide (DMF). All the components were mixed then dried in a fume hood until they were formed into pellets in a compression molder. Compressed samples were optically and electrically tested. Results show that composites that were only dried in the fume hood have a bubbled structure and reach percolation around 1-5 phr. The bubbles were determined to be coming from water that got into the samples while they were drying in the fume hood. Composites were placed in a furnace at 100°C for 1 hour to take the water out of them. Results showed that furnace dried samples have a smooth surface and are more resistive than the bubbled composites. The bubbled samples were most likely less resistive than samples with a smooth surface because during the bubble formation the CNTs are being pushed closer together causing percolation to happen sooner.
Wear Characteristics by Ti Coating of Al 7075
Authors: An Jihye , Im Sunghoon , Yoo Yunyoong , Noh Jungpil , Huh Sunchul
Published: June 2020

Al 7075 alloys are widely used in many mechanical parts because of their low density, light weight, and corrosion resistance. However, when mechanical parts are used in extreme environments such as high speed, high temperature, and high pressure, wear occurs more than allowable. To solve this problem, research and development of surface thin film deposition technology are increasing. Therefore, in this study, the wear characteristics were studied by depositing Ti films with excellent mechanical properties on Al 7075 according to the surface roughness by the deposition time. Results showed that 60’ sputtered specimens after polishing with alumina had the best wear resistance. In addition, the surface roughness of the base material and the deposition time of the thin film affected the wear resistance.
Luminescent Properties of Al2O3:xEu obtained by Rapid Combustion Synthesis
Authors: Viesca-Villanueva E. , Chavez D. , García C. R. , Esquivel B. , Martínez-Sánchez E. , Lopez-Badillo C.M.
Published: June 2020

In this work, Al
2
O
3:xEu
3+ were synthesized by the combustion method. The atomic concentration percentage of En doping was varied (x = 0%, 1%, 3%, 5% and 7at%). Structural and morphological properties were analyzed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques, respectively. The XRD patterns of the pure (x = 0%) and Eu-doped (x=1at%) show the single Al2O3 corundum phase. For the highest Eu-doped concentrations of x = 3%, x = 5% and x = 7at%, the Al2O3:xEu samples, present a mixture of phases of corundum (Al2O3) and EuAlO3 (perovskite). SEM images show irregular grains with average sizes in the range of 0.1 - 78.8 μm. Photoluminescence (PL) analysis show that all Eu-doped Al2O3 samples exhibits intense red-emission. PL spectra show two main peaks at 615 nm (5D0°7F2) and 700 nm (5D0°7F4). The x = 3at% Eu-doped sample presents the highest intensity under 256 nm excitation. CIE coordinates were calculated from the PL spectra, values around x= 0.6 and y= 0.3 (red emission) were obtained from all samples. Due to its strong luminescence those Al2O3:xEu phosphors could be good candidates for components in solid state lighting.
Potential Materials for Enhanced Oil Production from Northern oilfield, Thailand
Authors: Maneeintr K , Jiravivitpanya J , Meekoch T , Boonpramote T
Published: June 2020

One of enhanced oil recovery techniques to produce more oil production is surfactant flooding. The surfactants are considered as the effective chemicals used in oilfield in Thailand. It is used to lower the interfacial tension (IFT) of two fluids and to increase mobility in the reservoir. For this study, various chemicals such as amine, fatty alcohol and glycerine are applied as the surfactants to reduce IFT between oil and water. Therefore, the aim of this work is to investigate the potential chemicals and measure the IFT reduction based on the conditions of subsurface at the oilfield in Thailand. These parameters such as temperature, pressure as well as the concentration of surfactant are adjusted to investigate the effects on IFT reduction. From the results, it is reported that pressure from 1, 000 to 2, 000 psi and temperature varied from 70 °C to 90 °C can reduce IFT insignificantly. However, types of chemicals and surfactant concentration are the main parameters that impact on the IFT reduction. Monoethanolamine at 4.0 wt. % can greatly decrease IFT up to 87 % for surfactant concentration. Finally, the results can be applied to use in the real field for enhanced oil production in Thailand.
An Experimental Study on the Technique Optimization in Localization Process of 4J36 Invar Alloy-A Micro-Electrochemical Machining Perspective
Authors: Bian Jianxiao , Ma Baoji , Hu Yanwei , Jing Zhichen , Liu Xin
Published: June 2020

This study introduces electrochemical processing into the processing of 4J36 Invar alloy to obtain higher processing accuracy. An experimental study based on central composite design (CCD) was carried out to analyze the effects of voltage, duty cycle, feed rate, and inter-electrode gap on the localization of Invar processing. The response surface method is used to establish a mathematical model between process parameters and processing locality. The model shows that the minimum Side Gap is 158.7μm, and the prediction results are verified by experiments. The prediction error of the mathematical model is 1.44%, which means that the proposed optimal mathematical model can solve the optimal processing parameters of 4J36 Invar alloy.It has a positive significance for the wide application of Invar.
Early Warning of Position Accuracy for Pin Hole using Rules and Model based on LSSVM and PSO during Tractor Manufacturing Process
Authors: Jiang Chao , Li Ying , Zhao Zhilin , Cheng Fang
Published: June 2020

The factors affecting the processing quality of pin hole on the end face of tractor gearbox were analyzed. The main influencing factors on position accuracy of hole group include ambient temperature, the number of workpieces processed by drilling cutter and so on during precision manufacturing. The early warning rules of processing quality during tractor manufacturing process were proposed based on single-factor analysis and double-factors analysis. Then an early warning model for position accuracy of pin hole was established based on LSSVM while PSO was used to optimize the unknown parameters. The experimental results show that the RMSE of the model is 0.0058 and the RE is 0.075%, which verifies the validity of the established processing quality early warning model.
Job Shop Layout Improvement with Simulation Technique: A Case of Metal Sheet Production
Authors: Laosiritaworn Wimalin , Pinchai Nuchjira , Jarupuncharadsri Panitan
Published: June 2020

This paper investigates the improvement of job shop layout with simulation technique. A case study of Siam GN metal sheet, the manufacturer of customized metal sheet products was used. The objective is to increase production efficiency and reduce materials handling distance and time. Data regarding product and machine type were collected. CORELAP (Computerized Relationship Layout Planning) and Group technology based on ROC (rank order clustering) algorithm were applied to design the improved layouts. ARENA software was used to simulate the new layout from both techniques. The simulation show that CORELAP layout reduce production time by 17.12% while group technology layout reduces materials handling time by 11.41%. CORELAP layout therefore, was chosen for implementation. Simulation techniques allows user to experiment with different scenario hence selecting the most appropriate one without interfering with the actual process.
Fog-based Logistic Application Modeling in an Industry 4.0 Framework
Authors: BOUZARKOUNA Imen , SAHNOUN M’hammed , BAUDRY David , Amine BENATIA Mohamed , GOUT Christian
Published: June 2020

The industrial growth introduced the Industry 4.0 revolution, which uses several IoT-based technologies to manage the huge amount of data generated by its connected systems. This revolution aims to exchange data between the different parts and improve the performance of the manufacturing process. Facing several limitations, this paradigm needs the Fog Computing to ameliorate the Cloud services and the distribution of real-time decision-making and the secure and interoperable data analysis. The internal logistics presents the need to transmit and treat the data in real-time to take a more efficient decisions in a shorter delay. The Fog-based architecture is composed of terminal devices, Edge, Fog and Gateway devices. A model is presented to optimize the Fog integration (The cost of the links and nodes). Experimental results of an exact method optimization using Fico Xpress show a reduction of the Fog Computing integration cost in an internal logistic center.
Understanding the impact of gamma irradiation of epoxy titania nanocomposites on surface and bulk charge characteristics
Authors: Naveen J , Sarathi R , Imai T
Published: June 2020

Epoxy titania nanocomposites were prepared under optimum process conditions through shear mixing of titania nanoparticles in to epoxy resin, for its potential application as insulant in nuclear power plants and space applications. The complex intrinsic nature of properties, its characteristic variation due to ageing of nanocomposite insulating material upon its continuous exposure to gamma irradiation, and their charge trap and space charge characteristics are explored. Surface potential variation studies were carried out under DC voltage. In the present study, the charge trap performance was assessed under switching impulse voltage. It is observed that surface potential decay and shallow trap formation are high with gamma irradiated specimen. In addition, the potential decay is high under switching impulse voltage compared to DC voltage. Also, the trap depth formed is less under switching impulse voltage compared to DC voltage and it is high under negative DC voltage. The space charge analysis through Pulsed electro acoustic (PEA) studies has shown increase in accumulation of space charge and enhancement of electric field with increase in dosage of gamma-irradiation. Polarity reversal tests have revealed that the electric field enhancement is high before reversal of polarity, irrespective of level of gamma irradiation dosage. The direct correlation between characteristic variation in trap depth values with the gamma irradiated specimen and its contact angle was observed.
Contravariant forms on Whittaker modules
Authors: Brown Adam , Romanov Anna
Published: June 2020

Let

g

\mathfrak {g}

be a complex semisimple Lie algebra. We give a classification of contravariant forms on the nondegenerate Whittaker

g

\mathfrak {g}

-modules

Y
(
χ
,
η
)

Y(\chi , \eta )

introduced by Kostant. We prove that the set of all contravariant forms on

Y
(
χ
,
η
)

Y(\chi , \eta )

forms a vector space whose dimension is given by the cardinality of the Weyl group of

g

\mathfrak {g}

. We also describe a procedure for parabolically inducing contravariant forms. As a corollary, we deduce the existence of the Shapovalov form on a Verma module, and provide a formula for the dimension of the space of contravariant forms on the degenerate Whittaker modules

M
(
χ
,
η
)

M(\chi , \eta )

introduced by McDowell.
A support theorem for the Dunkl spherical mean operator
Authors: Ben Saïd Salem
Published: June 2020

We prove a support theorem for the Dunkl spherical mean operator. The proof relies on the decay of the total energy of the solutions to Euler-Poisson-Darboux type equations.
Uncertainty principle and its rigidity on complete gradient shrinking Ricci solitons
Authors: Mai Weixiong , Ou Jianyu
Published: June 2020

We prove rigidity theorems for shrinking gradient Ricci solitons supporting the Heisenberg-Pauli-Weyl uncertainty principle with the sharp constant in

R

n

\mathbb {R}^n

. In addition, we partially give analogous rigidity results of the Caffarelli-Kohn-Nirenberg inequalities on shrinking Ricci solitons.
The Barwise-Schlipf theorem
Authors: Enayat Ali , Schmerl James
Published: June 2020

In 1975 Barwise and Schlipf published a landmark paper whose main theorem asserts that a nonstandard model

M

\mathcal {M}

of

P
A

\mathsf {PA}

(Peano arithmetic) is recursively saturated iff

M

\mathcal {M}

has an expansion that satisfies the subsystem

Δ

1

1

\Delta _{1}^{1}

-

C
A

0

\mathsf {CA}_{0}

of second order arithmetic. In this paper we identify a crucial error in the Barwise–Schlipf proof of the right-to-left direction of the theorem, and we offer a correct proof of the problematic direction.
Review of Current Advances in Serologic Testing for COVID-19
Authors: Espejo Andrea P , Akgun Yamac , Al Mana Abdulaziz F , Tjendra Youley , Millan Nicolas C , Gomez-Fernandez Carmen , Cray Carolyn
Published: June 2020

Objectives

To examine and summarize the current literature on serologic methods for the detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods

A literature review was performed using searches in databases including PubMed, medRxiv, and bioRxiv. Thirty-two peer-reviewed papers and 23 preprints were examined.

Results

The studies included lateral flow immunoassay, enzyme-linked immunosorbent assay, chemiluminescence immunoassay, and neutralizing antibody assays. The use of all major SARS-CoV-2 antigens was demonstrated to have diagnostic value. Assays measuring total antibody reactivity had the highest sensitivity. In addition, all the methods provided opportunities to characterize the humoral immune response by isotype. The combined use of IgM and IgG detection resulted in a higher sensitivity than that observed when detecting either isotype alone. Although IgA was rarely studied, it was also demonstrated to be a sensitive marker of infection, and levels correlated with disease severity and neutralizing activity.

Conclusions

The use of serologic testing, in conjunction with reverse transcription polymerase chain reaction testing, was demonstrated to significantly increase the sensitivity of detection of patients infected with SARS-CoV-2. There was conflicting evidence regarding whether antibody titers correlated with clinical severity. However, preliminary investigations indicated some immunoassays may be a surrogate for the prediction of neutralizing antibody titers and the selection of recovered patients for convalescent serum donation.
Benchmarking variant callers in next-generation and third-generation sequencing analysis
Authors: Pei Surui , Liu Tao , Ren Xue , Li Weizhong , Chen Chongjian , Xie Zhi
Published: June 2020

DNA variants represent an important source of genetic variations among individuals. Next- generation sequencing (NGS) is the most popular technology for genome-wide variant calling. Third-generation sequencing (TGS) has also recently been used in genetic studies. Although many variant callers are available, no single caller can call both types of variants on NGS or TGS data with high sensitivity and specificity. In this study, we systematically evaluated 11 variant callers on 12 NGS and TGS datasets. For germline variant calling, we tested DNAseq and DNAscope modes from Sentieon, HaplotypeCaller mode from GATK and WGS mode from DeepVariant. All the four callers had comparable performance on NGS data and 30× coverage of WGS data was recommended. For germline variant calling on TGS data, we tested DNAseq mode from Sentieon, HaplotypeCaller mode from GATK and PACBIO mode from DeepVariant. All the three callers had similar performance in SNP calling, while DeepVariant outperformed the others in InDel calling. TGS detected more variants than NGS, particularly in complex and repetitive regions. For somatic variant calling on NGS, we tested TNscope and TNseq modes from Sentieon, MuTect2 mode from GATK, NeuSomatic, VarScan2, and Strelka2. TNscope and Mutect2 outperformed the other callers. A higher proportion of tumor sample purity (from 10 to 20%) significantly increased the recall value of calling. Finally, computational costs of the callers were compared and Sentieon required the least computational cost. These results suggest that careful selection of a tool and parameters is needed for accurate SNP or InDel calling under different scenarios.
HaDeX: an R package and web-server for analysis of data from hydrogen–deuterium exchange mass spectrometry experiments
Authors: Puchała Weronika , Burdukiewicz Michał , Kistowski Michał , Dąbrowska Katarzyna A , Badaczewska-Dawid Aleksandra E , Cysewski Dominik , Dadlez Michał
Published: June 2020

Motivation

Hydrogen–deuterium mass spectrometry (HDX-MS) is a rapidly developing technique for monitoring dynamics and interactions of proteins. The development of new devices has to be followed with new software suites addressing emerging standards in data analysis.

Results

We propose HaDeX, a novel tool for processing, analysis and visualization of HDX-MS experiments. HaDeX supports a reproducible analytical process, including data exploration, quality control and generation of publication-quality figures.

Availability and implementation

HaDeX is available primarily as a web-server (http://mslab-ibb.pl/shiny/HaDeX/), but its all functionalities are also accessible as the R package (https://CRAN.R-project.org/package=HaDeX) and standalone software (https://sourceforge.net/projects/HaDeX/).

Supplementary information

Supplementary data are available at Bioinformatics online.
HAPPI GWAS: Holistic Analysis with Pre- and Post-Integration GWAS
Authors: Slaten Marianne L , Chan Yen On , Shrestha Vivek , Lipka Alexander E , Angelovici Ruthie
Published: June 2020

Motivation

Advanced publicly available sequencing data from large populations have enabled informative genome-wide association studies (GWAS) that associate SNPs with phenotypic traits of interest. Many publicly available tools able to perform GWAS have been developed in response to increased demand. However, these tools lack a comprehensive pipeline that includes both pre-GWAS analysis, such as outlier removal, data transformation and calculation of Best Linear Unbiased Predictions or Best Linear Unbiased Estimates. In addition, post-GWAS analysis, such as haploblock analysis and candidate gene identification, is lacking.

Results

Here, we present Holistic Analysis with Pre- and Post-Integration (HAPPI) GWAS, an open-source GWAS tool able to perform pre-GWAS, GWAS and post-GWAS analysis in an automated pipeline using the command-line interface.

Availability and implementation

HAPPI GWAS is written in R for any Unix-like operating systems and is available on GitHub (https://github.com/Angelovici-Lab/HAPPI.GWAS.git).

Supplementary information

Supplementary data are available at Bioinformatics online.
The postcoital test in the development of new vaginal contraceptives†
Authors: Mauck Christine K , Vincent Kathleen L
Published: June 2020

Postcoital tests (PCTs) have been used for over a century in the clinical evaluation of infertile couples, and for nearly 70 years in the evaluation of new vaginal contraceptive products. PCTs have been largely replaced by more modern methods in the study of infertility, but they remain the most useful way to obtain preliminary data on the effectiveness of vaginal contraceptive products. The World Health Organization has described important aspects of the procedure. It involves collection of cervical mucus at a certain time point after intercourse and the counting and characterization of sperm found in the mucus. A wide range of progressively motile sperm (PMS) has been associated with pregnancy rates in infertility studies. Eligibility for contraceptive trials includes the requirement that couples achieve a certain threshold number of PMS per high power field at midcycle in a baseline cycle without the test product. The primary endpoint, or definition of a satisfactory result in test cycles, is predefined. A literature review identified 10 PCT studies of vaginal contraceptives involving nine test products. Phase II trials of vaginal contraceptives have not been deemed feasible in the development of any vaginal contraceptive to date. A PCT study of a test product can be predictive of contraceptive efficacy, although ultimate contraceptive effectiveness is influenced by the ease of use of the product, along with patient compliance. PCT results similar to results seen with products that later showed satisfactory performance in efficacy trials is the best indicator of likely success of a test product.
High-fat-diet induced obesity increases the proportion of linoleic acyl residues in dam serum and milk and in suckling neonate circulation
Authors: Suarez-Trujillo Aridany , Huff Katelyn , Ramires Ferreira Christina , Paschoal Sobreira Tiago Jose , Buhman Kimberly K , Casey Theresa
Published: June 2020

Maternal obesity increases the risk of offspring to become obese and develop related pathologies. Exposure to maternal high-fat diet (HFD) only during lactation increases the risk of obesity-related diseases, suggesting that factors in milk affect long-term health. We hypothesized that prepregnancy obesity induced by HFD alters milk lipidome, and in turn, alterations may affect neonate serum lipidome. The objective of this study was to determine the effect of prepregnancy obesity induced by HFD on circulating lipids in dams and neonates and in milk. Female mice were fed an HFD (60% kcal fat) or control diet (CON, 10% kcal fat) beginning 4 weeks before breeding. On postnatal day 2 (PND2), pups were cross-fostered to create pup groups exposed to HFD during pregnancy, lactation, or both or exposed to CON. On PND12, dams were milked and then euthanized along with pups to collect blood. Serum and milk were processed for multiple reaction monitoring (MRM) lipidomics profiling to quantify the relative expression of lipid classes. Lipidome of HFD dam serum and milk had increased proportion of C18:2 free fatty acid and fatty acyl residues in all lipid classes. Lipidome of serum from pups exposed to maternal HFD during lactation was similarly affected. Thus, maternal HFD induced redistribution of fatty acyl residues in the dam’s circulation, which was associated with modification in milk and suckling neonate’s lipidome. Further studies are needed to determine if increased circulating levels of C18:2 in neonate affects development and predisposes offspring to obesity and metabolic syndrome.
Nesfatin-1-like peptide suppresses hypothalamo–pituitary–gonadal mRNAs, gonadal steroidogenesis, and oocyte maturation in fish†
Authors: Rajeswari Jithine Jayakumar , Hatef Azadeh , Unniappan Suraj
Published: June 2020

Nucleobindin (Nucb)-1 and Nucb2 are DNA and Ca2+ binding proteins with multiple functions in vertebrates. Prohormone convertase-mediated processing of Nucb2 results in the production of biologically active nesfatin-1. Nesfatin-1 is involved in the regulation of reproduction in many vertebrates, including fish. Our lab originally reported a nesfatin-1-like peptide (Nlp) encoded in Nucb1 that exhibits nesfatin-1-like metabolic effects. We hypothesized that Nlp has a suppressive role in the reproductive physiology of fish. In this research, whether Nlp regulates reproductive hormones and oocyte maturation in fish were determined. Single intraperitoneal (IP) injection of goldfish Nlp (50 ng/g body weight) suppressed salmon and chicken gonadotropin-releasing hormone (sgnrh and cgnrh2), gonadotropin-inhibiting hormone (gnih) and its receptor (gnihr), and kisspeptin and brain aromatase mRNA expression in the hypothalamus of both male and female goldfish. In the pituitary, Nlp decreased mRNAs encoding lhb, fshb and kisspeptin and its receptor, while a significant increase in gnih and gnihr was observed. In the gonads, lh (only in male fish) and fsh receptor mRNAs were also significantly downregulated in Nlp-injected fish. Sex-specific modulation of gnih, gnihr, and kisspeptin system in the gonads was also observed. Nlp decreased sex steroidogenic enzyme encoding mRNAs and circulating levels of testosterone and estradiol. In addition, incubation of zebrafish ovarian follicles with Nlp resulted in a reduction in oocyte maturation. These results provide evidence for a robust role for Nlp in regulating reproductive hormones in goldfish and oocyte maturation in zebrafish, and these effects resemble that of nesfatin-1.
Left ventricular mechanical dispersion in ischaemic cardiomyopathy: association with myocardial scar burden and prognostic implications
Authors: Abou Rachid , Prihadi Edgard A , Goedemans Laurien , van der Geest Rob , El Mahdiui Mohammed , Schalij Martin J , Ajmone Marsan Nina , Bax Jeroen J , Delgado Victoria
Published: June 2020

Aims

Left ventricular (LV) mechanical dispersion (MD) may result from heterogeneous electrical conduction and is associated with adverse events. The present study investigated (i) the association between LV MD and the extent of LV scar as assessed with contrast-enhanced cardiac magnetic resonance (CMR) and (ii) the prognostic implications of LV MD in patients after ST-segment elevation myocardial infarction.

Methods and results

LV MD was calculated by echocardiography and myocardial scar was analysed on CMR data retrospectively. Infarct core and border zone were defined as ≥50% and 35–50% of maximal signal intensity, respectively. Patients were followed for the occurrence of the combined endpoint (all-cause mortality and appropriate implantable cardioverter-defibrillator therapy). In total, 96 patients (87% male, 57 ± 10 years) were included. Median LV MD was 53.5 ms [interquartile range (IQR) 43.4–62.8]. On CMR, total scar burden was 11.4% (IQR 3.8–17.1%), infarct core tissue 6.2% (IQR 2.0–12.7%), and border zone was 3.5% (IQR 1.5–5.7%). Correlations were observed between LV MD and infarct core (r = 0.517, P < 0.001), total scar burden (r = 0.497, P < 0.001), and border zone (r = 0.298, P = 0.003). In total, 14 patients (15%) reached the combined endpoint. Patients with LV MD >53.5 ms showed higher event rates as compared to their counterparts. Finally, LV MD showed the highest area under the curve for the prediction of the combined endpoint.

Conclusion

LV MD is correlated with LV scar burden. In addition, patients with prolonged LV MD showed higher event rates. Finally, LV MD provided the highest predictive value for the combined endpoint when compared with other parameters.
Evaluating Restoration Treatment Effectiveness through a Comparison of Residual Composition, Structure, and Spatial Pattern with Historical Reference Sites
Authors: LeFevre Miles E , Churchill Derek J , Larson Andrew J , Jeronimo Sean M A , Bass Jamie , Franklin Jerry F , Kane Van R
Published: June 2020

Forest-restoration efforts are increasing in the western United States in response to realized and expected changes in climate and disturbance regimes. Managers are challenged to find practical and defensible targets to shift forest composition, structure, and spatial pattern to a more resistant and resilient state. The Northeast Washington Forest Vision 2020 project on the Colville National Forest presented an opportunity to map and use previously uncaptured mesic stand-level historical reference conditions to a large restoration project. We reconstructed historical forest conditions in 12 plots across a range of plant-association groups and mapped five restoration treatment units after implementation. We evaluated treatment effectiveness both in terms of meeting the prescriptions’ stated objectives and by similarity to observed reference conditions using metrics of density, species composition, clump-size patterns, and open-space patterns. We found that dry plant associations were historically dominated by distributed clumps of large shade-intolerant trees, whereas cold mesic plant associations were structured as a gap-matrix spatial pattern. Treatments were effective at meeting prescribed density and species-composition targets, but generally resulted in stands that were overly uniform or clumped compared to historical reference conditions.
Comparison of Volumes Estimated from Breast Height and Stump Diameters: Application to Tectona grandis Data
Authors: Chukwu Onyekachi , Ogana Friday N , Nwatu Juliet U
Published: June 2020

Models estimating tree volume from stump diameter are important forest-management tools when volume estimation is needed postharvest, and dbh values are unavailable, for example the incidence of timber trespass. However, the use of stump diameter as the only independent variable for predicting tree volume has been limited. Therefore, in this article, stump diameter was used to estimate stem volume of Tectona grandis Linn. f, and this was compared with volume estimated from diameter at breast height. Five functions were considered each for the two stem diameters: simple linear, semilogarithmic, zero-intercept, power, and growth. Model assessment was based on least values of the root mean square error and Akaike information criterion. The results showed that the growth model had the best overall performance for both sets of volume models. A paired-sample t-test was used to compare volume estimated by stump diameter and volume estimated by diameter at breast height at 5 percent significance level. The results showed that there were no significant differences (P = .087) between timber volumes estimated from both stem diameters. Therefore, both diameters can be used interchangeably for modeling tree volume.
COVID-19 and Crosstalk With the Hallmarks of Aging
Authors: Salimi Shabnam , Hamlyn John M
Published: June 2020

Within the past several decades, the emergence of new viral diseases with severe health complications and mortality is evidence of an age-dependent, compromised bodily response to abrupt stress with concomitantly reduced immunity. The new severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, causes coronavirus disease 2019 (COVID-19). It has increased morbidity and mortality in persons with underlying chronic diseases and those with a compromised immune system regardless of age and in older adults who are more likely to have these conditions. While SARS-CoV-2 is highly virulent, there is variability in the severity of the disease and its complications in humans. Severe pneumonia, acute respiratory distress syndrome, lung fibrosis, cardiovascular events, acute kidney injury, stroke, hospitalization, and mortality have been reported that result from pathogen–host interactions. Hallmarks of aging, interacting with one another, have been proposed to influence health span in older adults, possibly via mechanisms regulating the immune system. Here, we review the potential roles of the hallmarks of aging, coupled with host–coronavirus interactions. Of these hallmarks, we focused on those that directly or indirectly interact with viral infections, including immunosenescence, inflammation and inflammasomes, adaptive immunosenescence, genomic instability, mitochondrial dysfunction, epigenetic alterations, telomere attrition, and impaired autophagy. These hallmarks likely contribute to the increased pathophysiological responses to SARS-CoV-2 among older adults and may play roles as an additive risk of accelerated biological aging even after recovery. We also briefly discuss the role of antiaging drug candidates that require paramount attention in COVID-19 research.
No Other Safe Care Option: Nursing Home Admission as a Last Resort Strategy
Authors: Campbell-Enns Heather J , Campbell Megan , Rieger Kendra L , Thompson Genevieve N , Doupe Malcolm B
Published: June 2020

Background and Objectives

Nursing homes are intended for older adults with the highest care needs. However, approximately 12% of all nursing home residents have similar care needs as older adults who live in the community and the reasons they are admitted to nursing homes is largely unstudied. The purpose of this study was to explore the reasons why lower-care nursing home residents are living in nursing homes.

Research Design and Methods

A qualitative interpretive description methodology was used to gather and analyze data describing lower-care nursing home resident and family member perspectives regarding factors influencing nursing home admission, including the facilitators and barriers to living in a community setting. Data were collected via semistructured interviews and field notes. Data were coded and sorted, and patterns were identified. This resulted in themes describing this experience.

Results

The main problem experienced by lower-care residents was living alone in the community. Residents and family members used many strategies to avoid safety crises in the community but experienced multiple care breakdowns in both community and health care settings. Nursing home admission was a strategy used to avoid a crisis when residents did not receive the needed support to remain in the community.

Discussion and Implications

To successfully remain in the community, older adults require specialized supports targeting mental health and substance use needs, as well as enhanced hospital discharge plans and improved information about community-based care options. Implications involve reforming policies and practices in both hospital and community-based care settings.
Loneliness Interacts With Cognition in Relation to Healthcare and Financial Decision Making Among Community-Dwelling Older Adults
Authors: Stewart Christopher C , Yu Lei , Glover Crystal M , Mottola Gary , Bennett David A , Wilson Robert S , Boyle Patricia A
Published: June 2020

Background and Objectives

Cognition is a known determinant of healthcare and financial decision making in old age. Social vulnerabilities also might play a role in such decisions; however, the evidence for this is less clear. Here, we examined the association of loneliness with decision making and tested the hypothesis that loneliness is associated with decision making via its interaction with global cognition.

Research Design and Methods

Participants were 1,121 nondemented older adults from the Rush Memory and Aging Project. Healthcare and financial decision making was assessed via a performance-based measure; loneliness was assessed via the De Jong Gierveld Loneliness Scale; and cognition was assessed via a 19-test neuropsychological battery.

Results

In a regression model adjusted for age, sex, and education, global cognition was associated with decision making (B = 2.43, SE = 0.14, p < .001) but loneliness was not (B = −0.04, SE = 0.11, p = .72). However, in a model including the interaction of loneliness with global cognition, the interaction was significant (B = 0.44, SE = 0.20, p = .03), such that the detrimental effect of loneliness on decision making was stronger when cognition was low. In secondary analyses examining the interaction of loneliness with 5 specific cognitive domains, the interaction between loneliness and working memory with decision making was significant (B = 0.35, SE = 0.15, p = .02).

Discussion and Implications

Our results suggest that loneliness compromises healthcare and financial decision making among older adults with lower global cognition and, more specifically, lower working memory.
The role of crustal models in the dynamics of the India–Eurasia collision zone
Authors: Singh Srishti , Ghosh Attreyee
Published: June 2020

We investigate how different crustal models can affect the stress field, velocities and associated deformation in the India–Eurasia collision zone. We calculate deviatoric stresses, which act as deformation indicators, from topographic load distribution and crustal heterogeneities coupled with density driven mantle convection constrained by tomography models. We use three different crustal models, CRUST2.0, CRUST1.0 and LITHO1.0 and observe that these models have different crustal thickness and densities. As a result, gravitational potential energy (GPE) calculated based on these densities and crustal thicknesses differ between these models and so do the associated deviatoric stresses. For GPE only models, LITHO1.0 provides a better constraint on deformation as it yields the least misfit (both orientation and relative magnitude) with the surface observations of strain rates, lithospheric stress, plate motions and earthquake moment tensors. However, when the stresses from GPE are added to those associated with mantle tractions arising from density-driven mantle convection, the coupled models in all cases provide a better fit to surface observations. The N–S tensional stresses predicted by CRUST2.0 in this area get reduced significantly due to addition of large N–S compressional stresses predicted by the tomography models S40RTS and SAW642AN leading to an overall strike-slip regime. On the other hand, the hybrid models, SINGH_S40RTS and SINGH_SAW that are obtained by embedding a regional P-wave model, Singh et al., in global models of S40RTS and SAW642AN, predict much lower compression within this area. These hybrid models provide a better constraint on surface observations when coupled with CRUST1.0 in central Tibet, whereas the combined LITHO1.0 plus mantle traction model provides a better fit in some other areas, but with a degradation of fit in central Tibet.
Association between health literacy and physical activity in older people: a systematic review and meta-analysis
Authors: Lim Mei Ling , van Schooten Kimberley S , Radford Kylie A , Delbaere Kim
Published: June 2020

Physical inactivity is common in older people and contributes to morbidity and mortality. Health literacy might play a role in motivating people to become or stay physically active. However, little is known about the influence of health literacy on physical activity in older people. This review aims to determine the association between health literacy and physical activity in older people. A systematic search was conducted in CINAHL, MEDLINE, PsychINFO and CENTRAL. Inclusion criteria: (i) community-dwelling people with an average age of ≥55 and (ii) reported on the association between health literacy and physical activity. Exclusion criteria: (i) population with a health condition and (ii) case study or qualitative study. Data were extracted independently by two reviewers. Risk of bias was assessed using the Downs and Black checklist. A meta-analysis was conducted using random-effects models with inverse variance. Thirteen articles were included in the review and five articles were selected for the meta-analysis. Older people with inadequate health literacy were 38% less likely than older people with adequate health literacy to report engaging in physical activity on ≥5 days per week [odds ratio = 0.62, 95% confidence interval (CI) 0.55–0.77]. Only two articles used activity monitors; the mean number of steps taken per day was not significantly different between older people with adequate and inadequate health literacy (standardized mean difference = −0.15, 95% CI −0.30 to 0.01). Physical activity could potentially be fostered by increasing health literacy and empowering older people to make beneficial health decisions.
No fibrous cap and pannus formation in an On-X mechanical aortic valve
Authors: Ryu Dae Woong , Choi Jong Bum
Published: June 2020

Mechanical cardiac valves placed in the aortic position can show different amounts of pannus under the aortic ring. A 68-year-old patient had undergone mitral annuloplasty with a 30-mm rigid ring and aortic valve replacement with a 21-mm On-X mechanical valve for mitral regurgitation and aortic valve stenosis 10 years and 3 months previously. In the second cardiac surgery for mitral valve replacement to treat mitral stenosis, the previously replaced On-X mechanical valve revealed no fibrous cap on the sewing cuff and no pannus on the lower border of the valve ring. These characteristic findings can be attributed to the unique design elements of this valve.
‘Digital pills’ for mental diseases: an ethical and social analysis of the issues behind the concept
Authors: de Miguel Beriain Iñigo , Morla González Marina
Published: June 2020

Recently, the US Food and Drug Administration has given a landmark approval to the very first digital pill with a sensor embedded in the inside. These are complex systems that include a drug and an electronic tracker that is activated when the patient takes the pill. Accordingly, they might be an excellent tool for monitoring and potentially improving patients’ adherence to prescriptions. This would serve well to avoid unnecessary healthcare costs and reduce the anxiety of patients and their relatives. However, digital pills might also diminish patient autonomy, reduce privacy, or promote inadequate use of pharmaceutical resources. This article is aimed at contributing to adequate use of this new tool by showing the main ethical and social issues they involve and proposing measures meant to address them. Finally, we conclude by defending the idea that these new systems should be seen as means of complementing traditional strategies to promote adherence to treatment, and not as substitutes.
Overlapping den tree selection by three declining arboreal mammal species in an Australian tropical savanna
Authors: Penton Cara E , Woolley Leigh-Ann , Radford Ian J , Murphy Brett P
Published: June 2020

Tree cavities are important denning sites for many arboreal mammals. Knowledge of cavity requirements of individual species, as well as potential den overlap among species, is integral to their conservation. In Australia’s tropical savannas, development of tree cavities is enhanced by high termite activity, and, conversely, reduced by frequent fires. However, it is poorly understood how the availability of tree cavities in the tropical savannas impacts tree cavity use and selection by cavity-dependent fauna. There has been a severe decline among arboreal mammal species in northern Australia over recent decades. Investigation of their cavity requirements may illuminate why these species have declined drastically in some areas but are persisting in others. Here we examined this issue in three species of arboreal mammals (Trichosurus vulpecula, Mesembriomys gouldii, Conilurus penicillatus) on Melville Island, northern Australia. We radiotracked individuals to their den sites to evaluate whether the species differ in their den tree and tree-cavity selection. The strongest influence on den tree selection was the presence of large cavities (> 10 cm entrance diameter), with all three species using larger cavities most frequently. Conilurus penicillatus, the smallest species, differed the most from the other species: it frequently was found in smaller, dead trees and its den sites were closer to the ground, including in hollow logs. The two larger species had broader den tree use, using larger live trees and dens higher up in the canopy. Dens of C. penicillatus are likely to be more susceptible to predation and destruction by high-intensity savanna fires. This may have contributed to this species’ rapid decline, both on Melville Island and on the mainland. However, the apparent preference for larger tree cavities by all three arboreal species is concerning due to the limited availability of large trees across Australian savannas, which are subject to frequent, high-intensity fires.
Diagnosis of primary osteosarcoma of the urinary bladder in a resource-limited setting: a case report and review of the literature
Authors: Mremi Alex , Pyuza Jeremia J , Bartholomeo Nicholas , Andongolile Alice A , Yahaya James J
Published: June 2020

Extraskeletal osteosarcoma is a rare malignant mesenchymal soft tissue tumor without attachment to the bone and is able to produce osteoid or cartilaginous matrix. Rendering a definitive diagnosis may pose a challenge particularly in a resource-limited setting. We report a case of primary osteosarcoma of the urinary bladder presenting with hematuria, dysuria and positive history of schistosomal contact. Computed tomography intravenous urogram revealed a large heterogeneous mass at the right superolateral aspect of the urinary bladder. Morphological evaluation of the biopsy and a minimal panel of immunohistochemical antibodies of vimentin and cytokeratin 20 ruled out potential differentials and thus confirmed the diagnosis of osteosarcoma.
The structure of the co-orbital stable regions as a function of the mass ratio
Authors: Liberato L , Winter O C
Published: June 2020

Although the search for extrasolar co-orbital bodies has not had success so far, it is believed that they must be as common as they are in the Solar system. Co-orbital systems have been widely studied, and there are several works on stability and even on formation. However, for the size and location of the stable regions, authors usually describe their results but do not provide a way to find them without numerical simulations, and, in most cases, the mass ratio value range is small. In this work, we study the structure of co-orbital stable regions for a wide range of mass ratio systems and build empirical equations to describe them. It allows estimating the size and location of co-orbital stable regions from a few system parameters. Thousands of massless particles were distributed in the co-orbital region of a massive secondary body and numerically simulated for a wide range of mass ratios (μ) adopting the planar circular restricted three-body problem. The results show that the upper limit of horseshoe regions is between 9.539 × 10−4 < μ < 1.192 × 10−3, which corresponds to a minimum angular distance from the secondary body to the separatrix of between 27.239º and 27.802º. We also found that the limit to existence of stability in the co-orbital region is about μ = 2.3313 × 10−2, much smaller than the value predicted by the linear theory. Polynomial functions to describe the stable region parameters were found, and they represent estimates of the angular and radial widths of the co-orbital stable regions for any system with 9.547 × 10−5 ≤ μ ≤ 2.331 × 10−2.
Characterizing continuum variability in the radio-loud narrow-line Seyfert 1 galaxy IRAS 17020+4544
Authors: Gonzalez A G , Gallo L C , Kosec P , Fabian A C , Alston W N , Berton M , Wilkins D R
Published: June 2020

We present results of temporal and spectral analyses on four XMM–Newton EPIC pn observations of IRAS 17020+4544, a narrow-line Seyfert 1 galaxy with evidence of a radio jet. Analysis of the light curves reveals that this radio-loud source does not behave like the bulk population of its radio-quiet counterparts. A trend of spectral hardening with increased flux is found. Variability is found to increase with energy, though it decreases as the spectrum hardens. The first 40 ks of the most recent observation behave uniquely among the epochs, exhibiting a softer spectral state than at any other time. Possible non-stationarity at low energies is found, with no such effect present at higher energies, suggesting at least two distinct spectral components. A reverberation signature is confirmed, with the lag-frequency, lag-energy, and covariance spectra changing significantly during the soft-state epoch. The temporal analysis suggests a variable power law in the presence of a reflection component, thus motivating such a fit for the 0.3−10 keV EPIC pn spectra from all epochs. We find an acceptable spectral fit using the timing-motivated parameters and report the detection of a broad Fe K emission line, requiring an additional model component beyond the reflection spectrum. We discuss links between this source and other narrow-line Seyfert 1 sources that show evidence of jet activity, finding similarities among this currently very limited sample of interesting objects.