bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Ensemble Learning in EEG Signal Analysis of Fatigue Driving
Authors: Rao Songhui , Li Kairui , Wu Jun , Mu Zhendong
Published: February 2021

Fatigue detection has now become an important direction of fatigue driving research. As a reliable physiological signal, EEG signals can be used to detect fatigue driving. This passage uses the idea of ensemble learning to establish an ensemble learning classification model of Bagged Tree, RSM Discrimination and RUSBoosted Tree, and uses the fatigue driving experiment data as the object to divide the fatigue driving object into normal state and fatigue state, using Pearson Correlation Coefficient method build a functional brain network. Six methods of Betweenness Centrality, Edge Betweenness Centrality, Clustering Coefficient, Degree, Local Efficiency, and Rich Club Coefficient are used to process and analyze six kinds of EEG signal characteristics, and then bring them into different in the ensemble learning model, the EEG signal characteristics and the ensemble learning model are matched and selected to improve the accuracy and stability of the detection model. By simulating 24 subjects, the results show that the accuracy and robustness of RSM Discrimination ensemble learning model and Degree method are the best, with an average accuracy rate of 90.35% and a standard deviation of 0.081.
Development of IoT-Based Volcano Early Warning System
Authors: Amaliya Virginia Fahriza , Lakudo Husein , Ulum Afrida Hafizhatul , Destarina Lisa , Seno Sensius , Rakhmadi Frida agung , Aminah Nina Siti , Evita Maria , Djamal Mitra
Published: February 2021

Monitoring volcanic activity this is indispensable for both research and disaster mitigation strategies. Therefore, the presence of volcano monitoring allows the monitoring, data recording and early warning system of volcanic activity from a distance that is real time. Volcanic monitoring system aims to detect any changes in volcanic status. Temperature and humidity become parameters of increased magma activity. Concentration of gasses includes SO2 and CO2, indicates of the depth of magma in volcanic conduit. Magma movement also triggers the earthquake.

The instrument that used in this research are temperature and humidity sensor DHT11, SO2 sensor TGS2602, CO2 sensor MG811, and vibration sensor ADXL345. Temperature and humidity sensors used DHT11 sensors that serve to detect temperature and humidity in the air. DHT11 sensors can detect temperature between 0-50°C and humidity between 20-90% RH. SO2 emissions were detected using TGS 2602 sensors that detects SO2 gas between 0-100 ppm. While CO2 gas emissions used MG811 sensors that detect the presence of CO2 gas between 350-10000 ppm. Furthermore, the vibrations were detected using a digital accelerometer ADXL345 that detects vibrations between 0.1-3200 Hz.

Data from all sensors processed using arduino promini microcontroller and then sent to ESP8266. ESP8266 is a wifi module that serves as a microcontroller enhancement to connect to wifi and create TCP / IP protocol. This module is also used to create an IoT project so that it can be accessed at any time on the web service page. This system will be assembled solar cells as a source of power supply.
Comparatives Studies in Molten Salt Reactor FUJI-U3 with Various Power
Authors: Wulandari Cici , Waris Abdul , Permana Sidik
Published: February 2021

Indonesia has a resource of nuclear fuel which spread around the country, especially in Bangka Belitung, West Kalimantan, West Sulawesi, and Papua. Therefore, Indonesia has a potential in the nuclear energy development. The Generation IV nuclear power system has been developed by the Generation IV Forum (GIF) with its benefits such as highly economical, enhanced safety, low waste production, and proliferation resistant. MSR is one of Generation IV nuclear power system which uses molten salt as a fuel and a coolant. Based on RUPTL (Electricity Supply Business Plan) PLN 2018-2027, Indonesia needs 100 MWe power harness from nuclear energy. This study focuses on a FUJI-U3 reactor, a type of MSR which developed in Japan. Power operation varied from 120-150 MWth 60-100 MWe and using FLiBe as molten salt. The calculation was performed with PIJ and CITATION modules in SRAC 2006 and JENDL 4.0 as nuclear data library.
Problem solution of the elasticity theory for the half-plane
Authors: Thanh L T , Linh H N T
Published: February 2021

The classical problem of equilibrium of elastic half-plane loaded along boundary contour can be resolved with different methods. In this paper, the solution is received with a new method that is founded on Cauchy-type integral and Plemelj identity. First, we solve with the general half-plane. Then we consider four special half-planes x2 ≤ 0, x2 ≥ 0, x1 ≤ 0, x1 ≥ 0.
Image Segmentation of Acute Myeloid Leukemia Using Multi Otsu Thresholding
Authors: Suryani E , Asmari E I , Harjito B
Published: February 2021

Acute Myeloid Leukemia (AML) can be identified by utilizing image processing. The stages used in the image processing process include preprocessing, segmentation, and feature extraction. The purpose of this segmentation is to separate objects in the image. One of the image segmentation methods is Multi Otsu Thresholding. This method has a way of working by looking for the threshold value dynamically. Previously there has been researched using the Static Otsu Thresholding method, but the results are still unsatisfactory because the threshold value obtained in the Static Thresholding method is that the threshold value obtained is static, meaning that the threshold value cannot adjust to the brightness level of each image that will be identified. With the background of the segmentation result dissatisfaction factor from the static threshold value, this study aims to carry out the segmentation process to obtain a dynamic threshold value, namely the Multi Otsu Thresholding Method. The Multi Otsu Thresholding method will be applied to segment AML images of M0 and M1 types, with the hope that the segmentation results obtained can be used for the feature extraction process better and are useful for the identification and classification process. Image processing methods used in this research are YCbCr color space, median filter, multi otsu thresholding, and morphological operations. The cell identification process utilizes the cell type classification process using the Naïve Bayes Classifier. The extracted characteristics were WBC (White Blood Cell) diameter, nucleus ratio, and nucleus roundness. Image data to test the process are 29 images of AML M0 and 30 images of AML M1. It was found that the segmentation results using the Multi Otsu Thresholding method can be used for the feature extraction process in AML M0 and AML M1 images and used for the identification process using the Naïve Bayes Classifier resulting in an accuracy of 83.81%, in this case, it has been compared with Static Otsu Thresholding which results with an accuracy of 75.35 %.
Particle approximation of the two-fluid model for superfluid 4He using smoothed particle hydrodynamics
Authors: Tsuzuki Satori
Published: February 2021

This paper presents a finite particle approximation of the two-fluid model for liquid 4He using smoothed particle hydrodynamics (SPH). In recent years, several studies have combined the vortex filament model (VFM), which describes quantized vortices in superfluid components, with the Navier–Stokes equations, which describe the motion of normal fluids. These studies led us to assume that coupling both components of the two-fluid model instead of using the VFM to describe the superfluid component enables us to approximate the system. In this study, we formulated a new SPH model that simultaneously solves both equations of motion of the two-fluid model. We then performed a numerical simulation of the rotating liquid 4He using our SPH. The results showed that the two major phenomena, the emergence of multiple independent vortices parallel to the circular axis and that of the so-called rigid-body rotation, can be reproduced by solving the two-fluid model using SPH. This finding is interesting because it was previously assumed that only a single vortex emerges when addressing similar problems without considering quantum mechanics. Our further analysis found that the emergence of multiple independent vortices can be realized by reformulating the viscosity term of the two-fluid model to conserve the angular momentum of the particles around their axes. Consequently, our model succeeded in reproducing the phenomena observed in quantum cases, even though we solve the phenomenological governing equations of liquid 4He.
RETRACTED: The impact of magnetohydrodynamic on bioconvection nanofluid flow with viscous dissipation and joule heating effects
Authors: Jawad Muhammad , Saeed Anwar , Bilal Muhammad , Gul Taza , Khan Arshad , Nasir Saleem
Published: February 2021

The current research work scrutinizes the bioconvection of nanofluid flow through an expanding sheet containing motile microorganisms with the mutual upshot of heat and mass transmission. Additionally, the convective and slip boundary conditions are also considered. The study is explored under the response of Joule heating, viscous dissipation, and magnetic strength. We used appropriate transformation methods for reducing a set of PDEs to nonlinear ODEs which were further corroborated by the ‘Homotopy Analysis Method’. The assessment is carried out for the numerous values of dissimilar parameters on the velocity and heat transmission profile with the inclusion of the density of motile microorganisms. It has been perceived that the rising trend in the magnetic field reduces the Nusselt number and the velocity near the stretch sheet of the fluid. The motile microorganisms profile displays a lessening behavior for rising values of Peclet number.
Differential risk of falls associated with pain medication among community-dwelling older adults by cognitive status
Authors: Yoshikawa Aya , Smith Matthew Lee , Ory Marcia G
Published: February 2021

Background

Persons living with dementia have an elevated risk of falling and chronic pain. This study investigates the relationship of pain medication use with falls among community-dwelling adults based on their cognitive status.

Methods

We analysed a nationally representative sample of community-dwelling Medicare beneficiaries (n = 7,491) who completed cognitive assessments used for dementia classification in the 2015 US National Health and Aging Trends Study. We performed survey-weighted logistic regression to investigate differential associations between pain medication use and a recent fall by cognitive status: no dementia, possible dementia and probable dementia, controlling for sociodemographic and health characteristics.

Results

About 16.5% of the analytic sample was classified as possible dementia (8.3%) and probable dementia (8.2%). Pain medication use was associated with a recent fall among those with probable dementia [odds ratio (OR) = 1.86, 95% confidence interval (CI): 1.14, 3.03], controlling for sociodemographic and health characteristics. Taking medication for pain 2 days a week or more (OR = 2.14, 95% CI: 1.20, 3.81) was associated with falls among those with probable dementia. Bothersome pain and worry about falling down were also associated with falls among participants with no dementia and possible dementia, respectively.

Conclusion

Differential risk factors for falls by cognitive status imply the need for tailored pain management and fall prevention strategies. The provision of fall prevention programmes stressing balance training and medication use is important regardless of cognitive status in community-dwelling older adults. Future research should explore other modifiable factors associated with the risk of falls among community-dwelling adults.
Transient Receptor Potential Melastatin 2 Enhances Vascular Reactivity During Development of Atherosclerosis in Mice
Authors: Dai Yi-quan , Yan Xiao-xiao , Lin Yi-chen , Chen Hong-yu , Liu Xiao-ru
Published: February 2021

Background

To investigate the function of transient receptor potential melastatin 2 (TRPM2) in vascular reactivity induced by 5-hydroxytryptamine (5-HT) in the aorta during development of atherosclerosis in mice.

Methods

Forty mice were randomly divided into 4 groups: C57BL/6J on normal diet (C57 + ND), C57BL/6J on high-fat diet (C57 + HFD), apolipoprotein E gene knockout mice (ApoE−/−) on ND (ApoE−/− + ND), and ApoE−/− on HFD (ApoE−/− + HFD). They were fed with a ND or HFD for 16 weeks. Aortic TRPM2 expression and isometric contractions were analyzed.

Results

In the ApoE−/− + HFD group, body weight, blood glucose, and blood lipid concentrations were increased, and aortic plaques were developed. Compared with the other 3 groups, aortic TRPM2 mRNA and protein levels were significantly increased in the ApoE−/− + HFD group (P < 0.01). Aortic reactivity to 5-HT was enhanced in ApoE−/− + HFD mice with lower EC50 values. The enhanced reactivity to 5-HT was significantly inhibited by TRPM2 inhibitors, N-p-amylcinnamoyl anthranilic acid (1 µmol/l) and 2-aminoethyl diphenylborinate (10 µmol/l).

Conclusions

Aortic TRPM2 expression is upregulated in ApoE knockout mice fed with a HFD. Upregulation of TRPM2 enhances 5-HT vascular reactivity during development of atherosclerosis.
Expression of adenylate kinase fused mouse ubiquitin active enzyme in Escherichia coli and its application in ubiquitination
Authors: Liu Xiaoliang , Hu Ling , Zhang Yuan , Li Hongtao
Published: February 2021

Ubiquitination is involved in the regulation of numerous cellular functions. Research works in the ubiquitin realm rely heavily on ubiquitination assays in vitro and require large amounts of ubiquitin-activating enzyme (UBA1) and keep ATP supplies. However, UBA1 is hard to be obtained with large quantities using reported methods. We fused Escherichia coli adenylate kinase (adk) and mouse UBA1 and obtained fusion protein adk-mUBA1. The expression level of adk-mUBA1 increased about 8-fold compared with mUBA1 in an E. coli expression system, and adk-mUBA1 was easily purified to 90% purity via 2 purification steps. The purified adk-mUBA1 protein was functional for ubiquitination and could use ATP in addition to ADP as energy supply and had a higher catalytic activity than mUBA1 in cell lysis. adk-mUBA1 can be applied to preparing ubiquitin-modified substrates and kinds of ubiquitin chains in a chemical synthesis process and is a preferable application than mUBA1 in vitro ubiquitination.
A variable selection approach for highly correlated predictors in high-dimensional genomic data
Authors: Zhu Wencan , Lévy-Leduc Céline , Ternès Nils
Published: February 2021

Motivation

In genomic studies, identifying biomarkers associated with a variable of interest is a major concern in biomedical research. Regularized approaches are classically used to perform variable selection in high-dimensional linear models. However, these methods can fail in highly correlated settings.

Results

We propose a novel variable selection approach called WLasso, taking these correlations into account. It consists in rewriting the initial high-dimensional linear model to remove the correlation between the biomarkers (predictors) and in applying the generalized Lasso criterion. The performance of WLasso is assessed using synthetic data in several scenarios and compared with recent alternative approaches. The results show that when the biomarkers are highly correlated, WLasso outperforms the other approaches in sparse high-dimensional frameworks. The method is also illustrated on publicly available gene expression data in breast cancer.

Availabilityand implementation

Our method is implemented in the WLasso R package which is available from the Comprehensive R Archive Network (CRAN).

Supplementary information

Supplementary data are available at Bioinformatics online.
METTL3-mediated m6A methylation negatively modulates autophagy to support porcine blastocyst development‡
Authors: Cao Zubing , Zhang Ling , Hong Renyun , Li Yunsheng , Wang Yiqing , Qi Xin , Ning Wei , Gao Di , Xu Tengteng , Ma Yangyang , Yu Tong , Knott Jason G , Sathanawongs Anucha , Zhang Yunhai
Published: February 2021

N6-methyladenosine (m6A) catalyzed by METTL3 regulates the maternal-to-zygotic transition in zebrafish and mice. However, the role and mechanism of METTL3-mediated m6A methylation in blastocyst development remains unclear. Here, we show that METTL3-mediated m6A methylation sustains porcine blastocyst development via negatively modulating autophagy. We found that reduced m6A levels triggered by METTL3 knockdown caused embryonic arrest during morula-blastocyst transition and developmental defects in trophectoderm cells. Intriguingly, overexpression of METTL3 in early embryos resulted in increased m6A levels and these embryos phenocopied METTL3 knockdown embryos. Mechanistically, METTL3 knockdown or overexpression resulted in a significant increase or decrease in expression of ATG5 (a key regulator of autophagy) and LC3 (an autophagy marker) in blastocysts, respectively. m6A modification of ATG5 mRNA mainly occurs at 3’UTR, and METTL3 knockdown enhanced ATG5 mRNA stability, suggesting that METTL3 negatively regulated autophagy in an m6A dependent manner. Furthermore, single-cell qPCR revealed that METTL3 knockdown only increased expression of LC3 and ATG5 in trophectoderm cells, indicating preferential inhibitory effects of METTL3 on autophagy activity in the trophectoderm lineage. Importantly, autophagy restoration by 3MA (an autophagy inhibitor) treatment partially rescued developmental defects of METTL3 knockdown blastocysts. Taken together, these results demonstrate that METTL3-mediated m6A methylation negatively modulates autophagy to support blastocyst development.
Ageing promotes pathological alpha-synuclein propagation and autonomic dysfunction in wild-type rats
Authors: Van Den Berge Nathalie , Ferreira Nelson , Mikkelsen Trine Werenberg , Alstrup Aage Kristian Olsen , Tamgüney Gültekin , Karlsson Páll , Terkelsen Astrid Juhl , Nyengaard Jens Randel , Jensen Poul Henning , Borghammer Per
Published: February 2021

Neuronal aggregates of misfolded alpha-synuclein protein are found in the brain and periphery of patients with Parkinson’s disease. Braak and colleagues have hypothesized that the initial formation of misfolded alpha-synuclein may start in the gut, and then spread to the brain via peripheral autonomic nerves hereby affecting several organs, including the heart and intestine. Age is considered the greatest risk factor for Parkinson’s disease, but the effect of age on the formation of pathology and its propagation has not been studied in detail. We aimed to investigate whether propagation of alpha-synuclein pathology from the gut to the brain is more efficient in old versus young wild-type rats, upon gastrointestinal injection of aggregated alpha-synuclein. Our results demonstrate a robust age-dependent gut-to-brain and brain-to-gut spread of alpha-synuclein pathology along the sympathetic and parasympathetic nerves, resulting in age-dependent dysfunction of the heart and stomach, as observed in patients with Parkinson’s disease. Moreover, alpha-synuclein pathology is more densely packed and resistant to enzymatic digestion in old rats, indicating an age-dependent maturation of alpha-synuclein aggregates. Our study is the first to provide a detailed investigation of alpha-synuclein pathology in several organs within one animal model, including the brain, skin, heart, intestine, spinal cord and autonomic ganglia. Taken together, our findings suggest that age is a crucial factor for alpha-synuclein aggregation and complete propagation to heart, stomach and skin, similar to patients. Given that age is the greatest risk factor for human Parkinson’s disease, it seems likely that older experimental animals will yield the most relevant and reliable findings. These results have important implications for future research to optimize diagnostics and therapeutics in Parkinson’s disease and other age-associated synucleinopathies. Increased emphasis should be placed on using aged animals in preclinical studies and to elucidate the nature of age-dependent interactions.
Accelerated Brain Aging and Cerebral Blood Flow Reduction in Persons With Human Immunodeficiency Virus
Authors: Petersen Kalen J , Metcalf Nicholas , Cooley Sarah , Tomov Dimitre , Vaida Florin , Paul Robert , Ances Beau M
Published: February 2021

Background

Persons with human immunodeficiency virus (PWH) are characterized by altered brain structure and function. As they attain normal lifespans, it has become crucial to understand potential interactions between human immunodeficiency virus (HIV) and aging. However, it remains unclear how brain aging varies with viral load (VL).

Methods

In this study, we compare magnetic resonance imaging (MRI) biomarkers among PWH with undetectable VL (UVL; ≤50 genomic copies/mL; n = 230), PWH with detectable VL (DVL; >50 copies/mL; n = 93), and HIV-uninfected (HIV–) controls (n = 206). To quantify gray matter cerebral blood flow (CBF), we utilized arterial spin labeling. To measure structural aging, we used a publicly available deep learning algorithm to estimate brain age from T1-weighted MRI. Cognitive performance was measured using a neuropsychological battery covering 5 domains.

Results

Associations between age and CBF varied with VL. Older PWH with DVL had reduced CBF vs PWH with UVL (P = .02). Structurally predicted brain aging was accelerated in PWH vs HIV– controls regardless of VL (P < .001). Overall, PWH had impaired learning, executive function, psychomotor speed, and language compared to HIV– controls. Structural brain aging was associated with reduced psychomotor speed (P < .001).

Conclusions

Brain aging in HIV is multifaceted. CBF depends on age and current VL and is improved by medication adherence. By contrast, structural aging is an indicator of cognitive function and reflects serostatus rather than current VL.
Physician-related predictors of referral for multidisciplinary paediatric obesity management: a population-based study
Authors: Gehring Nicole D , Kebbe Maryam , Rathwell Sarah , Perez Arnaldo , Peng Chenhui , Zendher Emily , Ho Josephine , Ball Geoff D C
Published: February 2021

Background

It is recommended that primary care-based physicians refer children with overweight and obesity to multidisciplinary paediatric obesity management, which can help to improve weight and health.

Objective

To determine predictors of referral to multidisciplinary paediatric obesity management.

Methods

This retrospective, population-level study included physicians who could refer 2–17 years old with a body mass index ≥85th percentile to one of three multidisciplinary paediatric obesity management clinics in Alberta, Canada. Physician demographic and procedural data were obtained from Practitioner Claims and Provider Registry maintained by Alberta Health from January 2014 to December 2017. Physician characteristics were compared based on whether they did or did not refer children for obesity management. Univariable and multivariable logistic regression models analysed associations between physician characteristics and referral making.

Results

Of the 3863 physicians (3468 family physicians, 395 paediatricians; 56% male; 49.3 ± 12.2 years old; 22.3 ± 12.6 years since graduation) practicing during the study period, 1358 (35.2%) referred at least one child for multidisciplinary paediatric obesity management. Multivariable regression revealed that female physicians (versus males) [odds ratio (OR): 1.68, 95% confidence interval (CI): 1.46–1.93; P < 0.0001], paediatricians (versus family physicians) (OR: 4.89, 95% CI: 3.85–6.21; P < 0.0001) and urban-based physicians (versus non-urban-based physicians) (OR: 2.17, 95% CI: 1.79–2.65; P < 0.0001) were more likely to refer children for multidisciplinary paediatric obesity management.

Conclusions

Approximately one-third of family physicians and paediatricians referred children for multidisciplinary paediatric obesity management. Strategies are needed to improve referral practices for managing paediatric obesity, especially among male physicians, family physicians and non-urban-based physicians as they were less likely to refer children.
Robust deep learning seismic inversion witha prioriinitial model constraint
Authors: Zhang Jian , Li Jingye , Chen Xiaohong , Li Yuanqiang , Huang Guangtan , Chen Yangkang
Published: February 2021

Seismic inversion is one of the most commonly used methods in the oil and gas industry for reservoir characterization from observed seismic data. Deep learning (DL) is emerging as a data-driven approach that can effectively solve the inverse problem. However, existing DL-based methods for seismic inversion utilize only seismic data as input, which often leads to poor stability of the inversion results. Besides, it has always been challenging to train a robust network since the real survey has limited labelled data pairs. To partially overcome these issues, we develop a neural network framework with a priori initial model constraint to perform seismic inversion. Our network uses two parts as one input for training. One is the seismic data, and the other is the subsurface background model. The labels for each input are the actual model. The proposed method is performed by log-to-log strategy. The training data set is first generated based on forward modelling. The network is then pre-trained using the synthetic training data set, which is further validated using synthetic data that have not been used in the training step. After obtaining the pre-trained network, we introduce the transfer learning strategy to fine-tune the pre-trained network using labelled data pairs from a real survey to acquire better inversion results in the real survey. The validity of the proposed framework is demonstrated using synthetic 2-D data including both post-stack and pre-stack examples, as well as a real 3-D post-stack seismic data set from the western Canadian sedimentary basin.
Noradrenergic Enhancement of Motor Learning, Attention, and Working Memory in Humans
Authors: Kuo Hsiao-I , Qi Feng-Xue , Paulus Walter , Kuo Min-Fang , Nitsche Michael A
Published: February 2021

Background

Noradrenaline has an important role as a neuromodulator of the central nervous system. Noradrenergic enhancement was recently shown to enhance glutamate-dependent cortical facilitation and long term potentiation-like plasticity. As cortical excitability and plasticity are closely linked to various cognitive processes, here we aimed to explore whether these alterations are associated with respective cognitive performance changes. Specifically, we assessed the impact of noradrenergic enhancement on motor learning (serial reaction time task), attentional processes (Stroop interference task), and working memory performance (n-back letter task).

Methods

The study was conducted in a cross-over design. Twenty-five healthy humans performed the respective cognitive tasks after a single dose of the noradrenaline reuptake inhibitor reboxetine or placebo administration.

Results

The results show that motor learning, attentional processes, and working memory performance in healthy participants were improved by reboxetine application compared with placebo.

Conclusions

The results of the present study thus suggest that noradrenergic enhancement can improve memory formation and executive functions in healthy humans. The respective changes are in line with related effects of noradrenaline on cortical excitability and plasticity.
Persistent SARS-CoV-2 RNA Shedding Without Evidence of Infectiousness: A Cohort Study of Individuals With COVID-19
Authors: Owusu Daniel , Pomeroy Mary A , Lewis Nathaniel M , Wadhwa Ashutosh , Yousaf Anna R , Whitaker Brett , Dietrich Elizabeth , Hall Aron J , Chu Victoria , Thornburg Natalie , Christensen Kimberly , Kiphibane Tair , Willardson Sarah , Westergaard Ryan , Dasu Trivikram , Pray Ian W , Bhattacharyya Sanjib , Dunn Angela , Tate Jacqueline E , Kirking Hannah L , Matanock Almea ,   Household Transmission Study Team, Duca Lindsey M , Rabold Elizabeth , Gharpure Radhika , Njuguna Henry , Dawson Patrick , Conners Erin E , Fields Victoria , Salvatore Phillip , Marcenac Perrine , Reses Hannah E , Fajans Mark , Laws Rebecca L , Yin Sherry , Ye Dongni , Pevzner Eric , Battey Katherine , Tran Cuc , O’Hegarty Michelle , Vuong Jeni , Chancey Rebecca J , Gregory Christopher J , Banks Michelle , Rispens Jared , Lester Sandra , Mills Lisa , Fry Alicia , Nabity Scott , Freeman Brandi , Buono Sean
Published: February 2021

Background

To better understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding and infectivity, we estimated SARS-CoV-2 RNA shedding duration, described participant characteristics associated with the first negative rRT-PCR test (resolution), and determined if replication-competent viruses was recoverable ≥10 days after symptom onset.

Methods

We collected serial nasopharyngeal specimens from 109 individuals with rRT-PCR–confirmed COVID-19 in Utah and Wisconsin. We calculated viral RNA shedding resolution probability using the Kaplan-Meier estimator and evaluated characteristics associated with shedding resolution using Cox proportional hazards regression. We attempted viral culture for 35 rRT-PCR–positive nasopharyngeal specimens collected ≥10 days after symptom onset.

Results

The likelihood of viral RNA shedding resolution at 10 days after symptom onset was approximately 3%. Time to shedding resolution was shorter among participants aged <18 years (adjusted hazards ratio [aHR], 3.01; 95% confidence interval [CI], 1.6–5.6) and longer among those aged ≥50 years (aHR, 0.50; 95% CI, .3–.9) compared to participants aged 18–49 years. No replication-competent viruses were recovered.

Conclusions

Although most patients were positive for SARS-CoV-2 for ≥10 days after symptom onset, our findings suggest that individuals with mild to moderate COVID-19 are unlikely to be infectious ≥10 days after symptom onset.
The Activin/Follistatin Axis Is Severely Deregulated in COVID-19 and Independently Associated With In-Hospital Mortality
Authors: Synolaki Evgenia , Papadopoulos Vasileios , Divolis Georgios , Tsahouridou Olga , Gavriilidis Efstratios , Loli Georgia , Gavriil Ariana , Tsigalou Christina , Tziolos Nikolaos R , Sertaridou Eleni , Kalra Bhanu , Kumar Ajay , Rafailidis Petros , Pasternack Arja , Boumpas Dimitrios T , Germanidis Georgios , Ritvos Olli , Metallidis Simeon , Skendros Panagiotis , Sideras Paschalis
Published: February 2021

Background

Activins are members of the transforming growth factor-β superfamily implicated in the pathogenesis of several immunoinflammatory disorders. Based on our previous studies demonstrating that overexpression of activin-A in murine lung causes pathology sharing key features of coronavirus disease 2019 (COVID-19), we hypothesized that activins and their natural inhibitor follistatin might be particularly relevant to COVID-19 pathophysiology.

Methods

Activin-A, activin-B, and follistatin were retrospectively analyzed in 574 serum samples from 263 COVID-19 patients hospitalized in 3 independent centers, and compared with demographic, clinical, and laboratory parameters. Optimal scaling with ridge regression was used to screen variables and establish a prediction model.

Result

The activin/follistatin axis was significantly deregulated during the course of COVID-19, correlated with severity and independently associated with mortality. FACT-CLINYCoD, a scoring system incorporating follistatin, activin-A, activin-B, C-reactive protein, lactate dehydrogenase, intensive care unit admission, neutrophil/lymphocyte ratio, age, comorbidities, and D-dimers, efficiently predicted fatal outcome (area under the curve [AUC], 0.951; 95% confidence interval, .919−.983; P <10−6). Two validation cohorts indicated similar AUC values.

Conclusions

This study demonstrates a link between activin/follistatin axis and COVID-19 mortality and introduces FACT-CLINYCoD, a novel pathophysiology-based tool that allows dynamic prediction of disease outcome, supporting clinical decision making.
Allele-based analysis revealed the critical functions of region 277–297 in the NorA efflux pump of Staphylococcus aureus
Authors: Shang Yan , Lv Peiwen , Li Shannan , Wang Wenkai , Liu Yuanxiang , Yang Chunyu
Published: February 2021

Objectives

The NorA efflux pump in Staphylococcus aureus mediates resistance to many fluoroquinolone (FQ) antibiotics. Three norA alleles with high sequence similarity are found in various S. aureus strains exhibiting different FQ resistance profiles. This study aimed to elucidate the underlying molecular basis for the varying efflux activity of these three allelic variations.

Methods

The norA genotypes of 20 S. aureus isolates were analysed. Multiple alignments and conservative analyses were conducted to explore the evolutionary variations. After heterologous expression in Escherichia coli, seven mutants were constructed for MIC tests, efflux activity and conformational change measurements.

Results

Three NorA alleles were identified that displayed different FQ MICs and varying efflux activity for ethidium bromide, with the NorAII protein showing the strongest activity. A total of 29 single amino acid polymorphisms were identified by conservative analysis within three allelic peptides, with seven sites densely distributed in the 277–297 region. Mutations of these seven residues in NorAII all significantly impaired drug resistance and efflux activity, and three key mutants showed conformational changes in fluorescence resonance energy transfer (FRET) analysis.

Conclusions

Evolutionary variations of the 277–297 region could be a major explanation for the functional difference of three norA alleles and serve as a potential target for the development of novel NorA inhibitors.
Dissemination mechanisms of NDM genes in hospitalized patients
Authors: Zhai Yuting , Lee Shinyoung , Teng Lin , Ma Zhengxin , Hilliard Nicole B , May Robert J , Brown Scott A , Yu Fahong , Desear Kathryn E , Cherabuddi Kartik , Rand Kenneth H , Morris J Glenn , Iovine Nicole M , Jeong KwangCheol C
Published: February 2021

Background

NDM-producing Enterobacteriaceae are a major clinical concern worldwide. We characterized NDM-positive pathogens isolated from patients and assessed the dissemination patterns of the blaNDM genes in a hospital setting.

Methods

Eleven NDM-positive Enterobacteriaceae (three Enterobacter hormaechei, six Klebsiella pneumoniae and two Escherichia coli) were isolated from nine patients over a 1 year period. Antimicrobial susceptibility was assessed by MICs. A combination of short- and long-read WGS was used for genome analysis. Clinical treatment history of patients was linked with genetic features of individual isolates to investigate the dissemination patterns of the blaNDM genes and NDM-positive strains.

Results

bla NDM in clonal K. pneumoniae were transmitted between two patients. In other instances, an identical IncC plasmid encoding NDM-1 was transmitted between E. coli and K. pneumoniae isolated from the same patient, and an IncX3 plasmid, carrying blaNDM-1 or blaNDM-5, was harboured in non-clonal E. hormaechei. Varying patterns of IS elements were identified as a critical transmission mechanism in association with blaNDM genes.

Conclusions

Multiple transmission patterns were identified in hospitalized patients, including dissemination of clonal bacterial strains carrying resistance genes and horizontal transfer of resistance genes among divergent bacterial strains. Controlling spread of NDM is complex: while attention to standard infection control practices is critically important, this needs to be matched by aggressive efforts to limit unnecessary antimicrobial use, to minimize the selection for and risk of transfer of ‘high mobility’ resistance genes among Enterobacteriaceae.
Comparison of Lethal Doses Calculated Using Logit/Probit–Log(Dose) Regressions With Arbitrary Slopes Using R
Authors: Peng Xiaowei , Lei Chengfeng , Sun Xiulian
Published: February 2021

The median lethal dose (LD50) is commonly used to indicate acute toxicity of an insecticide to an insect species. Approximate confidence intervals for LD50s are often calculated using the Fieller and delta methods. It is often necessary to compare the relative potencies of several insecticides with a population or of one insecticide with different populations. Comparing the LD50s using probit/logit–log(dose) regressions with parallel slopes can be implemented in many software packages, but for the cases with arbitrary slopes are not generally available. We used the glm function in R to calculate and compare lethal doses without assuming equal slopes. Bioassay datasets from the literature fitted using the logit model gave the 95% confidence limits (95% CLs) for the lethal doses using Fieller’s theorem and incorporating a heterogeneity factor identical to the 95% CLs determined using the PoloPlus software. The delta method gave 95% CLs identical to the 95% CLs determined using the R drc package. The same datasets fitted using the probit model gave 95% CLs similar to the 95% CLs determined using PoloPlus and the drc package. The natural response rates for the control group were included using Abbott’s equation. When the potency ratio method and the z-test were used to identify differences between two lethal doses, and when the χ2 and log likelihood ratio tests were used to determine whether the regression lines were parallel, the conclusions were the same as those gave by PoloPlus and the drc package.
Geophysical investigations for stability and safety mitigation of regional crude-oil pipeline near abandoned coal mines
Authors: Butchibabu B , Khan Prosanta Kumar , Jha P C
Published: February 2021

This study aims for the protection of a crude-oil pipeline, buried at a shallow depth, against a probable environmental hazard and pilferage. Both surface and borehole geophysical techniques such as electrical resistivity tomography (ERT), ground penetrating radar (GPR), surface seismic refraction tomography (SRT), cross-hole seismic tomography (CST) and cross-hole seismic profiling (CSP) were used to map the vulnerable zones. Data were acquired using ERT, GPR and SRT along the pipeline for a length of 750 m, and across the pipeline for a length of 4096 m (over 16 profiles of ERT and SRT with a separation of 50 m) for high-resolution imaging of the near-surface features. Borehole techniques, based on six CSP and three CST, were carried out at potentially vulnerable locations up to a depth of 30 m to complement the surface mapping with high-resolution imaging of deeper features. The ERT results revealed the presence of voids or cavities below the pipeline. A major weak zone was identified at the central part of the study area extending significantly deep into the subsurface. CSP and CST results also confirmed the presence of weak zones below the pipeline. The integrated geophysical investigations helped to detect the old workings and a deformation zone in the overburden. These features near the pipeline produced instability leading to deformation in the overburden, and led to subsidence in close vicinity of the concerned area. The area for imminent subsidence, proposed based on the results of the present comprehensive geophysical investigations, was found critical for the pipeline.
The influence of advance speed on overburden movement characteristics in longwall coal mining: insight from theoretical analysis and physical simulation
Authors: Han Penghua , Zhang Cun , Ren Zhaopeng , He Xiang , Jia Sheng
Published: February 2021

The advance speed of a longwall face is an essential factor affecting the mining pressure and overburden movement, and an effective approach for choosing a reasonable advance speed to realise coal mine safety and efficient production is needed. To clarify the influence of advance speed on the overburden movement law of a fully mechanised longwall face, a time-space subsidence model of overburden movement is established by the continuous medium analysis method. The movement law of overburden in terms of the advance speed is obtained, and mining stress characteristics at different advance speeds are reasonably explained. The theoretical results of this model are further verified by a physical simulation experiment. The results support the following conclusions. (i) With increasing advance speed of the longwall face, the first (periodic) rupture interval of the main roof and the key stratum increase, while the subsidence of the roof, the fracture angle and the rotation angle of the roof decrease. (ii) With increasing advance speed, the roof displacement range decreases gradually, and the influence range of the advance speed on the roof subsidence is 75 m behind the longwall face. (iii) An increase in the advance speed of the longwall face from 4.89 to 15.23 m/d (daily advancing of the longwall face) results in a 3.28% increase in the impact load caused by the sliding instability of the fractured rock of the main roof and a 5.79% decrease in the additional load caused by the rotation of the main roof, ultimately resulting in a 9.63% increase in the average dynamic load coefficient of the support. The roof subsidence model based on advance speed is proposed to provide theoretical support for rational mining design and mining-pressure-control early warning for a fully mechanised longwall face.
Formal Hierarchies and Informal Networks: How Organizational Structure Shapes Information Search in Local Government
Authors: Whetsell Travis A , Kroll Alexander , DeHart-Davis Leisha
Published: February 2021

Attention to informal communication networks within public organizations has grown in recent decades. While research has documented the role of individual cognition and social structure in understanding information search in organizations, this article emphasizes the importance of formal hierarchy. We argue that the structural attributes of bureaucracies are too important to be neglected when modeling knowledge flows in public organizations. Empirically, we examine interpersonal information-seeking patterns among 143 employees in a small city government, using exponential random graph modeling (ERGM). The results suggest that formal structure strongly shapes information search patterns while accounting for social network variables and individual-level perceptions. We find that formal status, permission pathways, and departmental membership all affect employees’ information search. Understanding the effects of organizational structure on information search networks will offer opportunities to improve information flows in public organizations via design choices.
Short overview on the relevance of microRNA–reactive oxygen species (ROS) interactions and lipid peroxidation for modulation of oxidative stress-mediated signalling pathways in cancer treatment
Authors: Ulker Ozge Cemiloglu , Panieri Emiliano , Suzen Sibel , Jaganjac Morana , Zarkovic Neven , Saso Luciano
Published: February 2021

Objectives

Modulation of oxidative stress-mediated signalling pathways is constantly getting more attention as a valuable therapeutic strategy in cancer treatment. Although complexity of redox signalling pathways might represent a major hurdle, the development of advanced -omics technologies allow thorough studies on cancer-specific biology, which is essential to elucidate the impact of these signalling pathways in cancer cells. The scope of our review is to provide updated information about recent developments in cancer treatment.

Key findings

In recent years identifying oxidative stress-mediated signalling pathways is a major goal of cancer research assuming it may provide novel therapeutic approaches through the development of agents that may have better tissue penetration and therefore affect specific redox signalling pathways. In this review, we discuss some recent studies focussed on the modulation of oxidative stress-related signalling pathways as a novel anti-cancer treatment, with a particular emphasis on the induction of lipid peroxidation.

Conclusions

Characterization and modulation of oxidative stress-mediated signalling pathways and lipid peroxidation products will continue to foster novel interest and further investigations, which may pave the way for more effective, selective, and personalized integrative biomedicine treatment strategies.
Measuring neck circumference to predict and detect haemorrhage following thyroid surgery. A case series and literature review
Authors: Ezzy Mohsen A , Elshafei Moustafa H , Sharaan Mohamed A
Published: February 2021

Post-thyroidectomy bleeding is a fortunately rare but potentially life-threatening complication that may increase postoperative morbidity and hospital stay. In this case series, we demonstrate the relation between the measurement of neck circumference and haemorrhage following thyroid surgery and the value of this measurement in predicting post-thyroidectomy haemorrhage.

Currently, there is no simple and reliable method available for the early detection of post-thyroidectomy bleeding. Continuous pressure measurement could be a potential tool for the early detection of haemorrhage but is invasive, and more data are required to recommend threshold values for revision surgery. Early recognition and prompt surgical intervention are key to the management of cervical haematoma. Measurement of the neck circumference is a valuable adjunct tool in the early recognition of post-thyroidectomy bleeding. In this case series, we concluded that a 4-cm increase in neck circumference may trigger the clinical decision for cervical exploration.
In vivo study of hypericin-loaded poloxamer-based mucoadhesive in situ gelling liquid crystalline precursor system in a mice model of vulvovaginal candidiasis
Authors: de Araújo Patricia Rocha , Calixto Giovana Maria Fioramonti , Araújo Victor Hugo Sousa , Sato Mariana Rillo , Rodero Camila Fernanda , Oshiro-Junior João Augusto , Bauab Taís Maria , Chorilli Marlus
Published: February 2021

The present study reports the performance of the pigment hypericin (HYP)-loaded poloxamer-based mucoadhesive in situ gelling liquid crystalline precursor system (LCPS) for the treatment of vulvovaginal candidiasis (VVC) in mice. LCPS composed of 40% of ethoxylated and propoxylated cetyl alcohol, 30% of oleic acid and cholesterol (7:1), 30% of a dispersion of 16% poloxamer 407 and 0.05% of HYP (HYP-LCPS) was prepared and characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS) and ex vivo permeation and retention studies across vaginal porcine mucosa were performed. In addition, the antifungal properties of the HYP-LCPS were evaluated in a murine in vivo model; for this, infected C57BL female mice groups were treated with both HYP in solution and HYP-LCPS, and after 6 days colony forming unit (CFU)/ml count was performed. PLM and SAXS confirmed that HYP-LCPS is a microemulsion situated in boundary transition region confirming its action as an LCPS. When in contact with simulated vaginal fluid, HYP-LCPS became rigid and exhibited maltase crosses and bragg peaks characteristics of lamellar phase. Ex vivo permeation and retention studies showed that HYP-LCPS provides a localized treatment on the superficial layers of porcine vaginal mucosa. HYP-LCPS induced a significant reduction in the number of CFU/ml in the mice; thus this formulation indicated it is as effective as a commercial dosage form. It was concluded that LCPS maintains the biological activity of HYP and provides an adequate drug delivery system for this lipophilic molecule at the vaginal mucosa, being a promising option in cases of VVC.