bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the SARS-Cov-2 epidemic in Lombardy (Italy) in its early phase. Are we going in the right direction?
Authors: Riccio Angelo 
Published: April 2020

AbstractBACKGROUNDWe described the epidemiological features of the codiv-19 outbreak, and evaluated the impact of interventions measures on the epidemic in the Lombardy region, Italy.METHODSLaboratory-confirmed covid-19 cases reported through the beginning of April were extracted from the Italian Civil Protection database. Based on key events and interventions, we divided the epidemic into three periods: before February 21, from February 22 to early March, after early March. We compared epidemiological characteristics across periods and developed a modified susceptible-exposed-infectious-recovered model to study the epidemic and evaluate the impact of interventions. We explicitly took into account for unascertained cases (positive cases with no symptoms or mild symptoms that have not been accounted for in official statistics).RESULTSCurrently, the number of positive active cases has increased to around 30,000 in the Lombardy region. Due to restriction measures, the effective reproduction number dropped from 3.33 (95% CI: 2.03–3.69) during the first period, to 2.36 (95% CI: 2.21–2.70) during the second period. In the third period, the effective reproduction number is estimated to have dropped to 1.49 (95% CI: 1.35–1.62). The model estimates a great proportion of unascertained cases, about 90% of infected people has not been accounted for in official statistics.CONCLUSIONSConsiderable countermeasures have slowed down the covid-19 outbreak in the Lombardy region. However, notwithstanding the long-lasting lockdown period, the epidemic is still not under control. The effective reproduction number, according to the model used in this work, is still greater than 1.0. Estimation of unascertained cases has important implications on continuing surveillance and interventions.
Markovian Random Walk Modeling and Visualization of the Epidemic Spread of COVID-19
Authors: Akay Haluk , Barbastathis George 
Published: April 2020

AbstractThe epidemic spread of CoVID-19 has resulted in confirmed cases of viral respiratory illness in more than 1.4 million people around the world as of April 7th, 2020 [1]. However, different regions have experienced the spread of this disease differently. Here, we develop a Markovian random-walk spatial extension of a quarantine-enhanced SIR model to measure, visualize and forecast the effect of susceptible population density, testing rate, and social distancing and quarantine policies on epidemic spreading. The model is used to simulate the spread of CoVID-19 in the regions of Hubei, China; South Korea; Iran; and Spain. The model allows for evaluating the results of different policies both quantitatively and visually as means of better understanding and controlling the spread of the disease.
Long-term Coexistence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) with Antibody Response in Coronavirus Disease 2019 (COVID-19) Patients
Authors: Wang Bin , Wang Li , Kong Xianggen , Geng Jin , Xiao Di , Ma Chunhong , Jiang Xue-Mei , Wang Pei-Hui 
Published: April 2020

AbstractSevere acute respiratory syndrome coronavirus 2 infection causing coronavirus disease 2019 has spread worldwide. Whether antibodies are important for the adaptive immune responses against SARS-CoV-2 infection needs to be determined. Here, 26 cases of COVID-19 in Jinan, China, were examined and shown to be mild or with common clinical symptoms and no cases of severe symptoms were found among these patients. A striking feature of some patients is that SARS-CoV-2 could exist in patients who have virus-specific IgG antibodies for a very long period, with two cases for up to 50 days. One COVID-19 patient who did not produce any SARS-CoV-2-bound IgG successfully cleared SARS-CoV-2 after 46 days of illness, revealing that without antibody-mediated adaptive immunity, innate immunity may still be powerful enough to eliminate SARS-CoV-2. Overall, this report may provide a basis for further analysis of both innate and adaptive immunity in SARS-CoV-2 clearance, especially in non-severe cases. This study also has implications for understanding the pathogenesis and treatment of SARS-CoV-2.
Age could be driving variable SARS-CoV-2 epidemic trajectories worldwide
Authors: Ayoub Houssein H. , Chemaitelly Hiam , Seedat Shaheen , Mumtaz Ghina R. , Makhoul Monia , Abu-Raddad Laith J. 
Published: April 2020

AbstractBackgroundCurrent geographic spread of documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections shows heterogeneity. This study explores the role of age in potentially driving differentials in infection spread, epidemic potential, and rates of disease severity and mortality across countries.MethodsAn age-stratified deterministic mathematical model that describes SARS-CoV-2 transmission dynamics was applied to 159 countries and territories with a population ≥1 million.ResultsAssuming worst-case scenario for the pandemic, the results indicate that there could be stark regional differences in epidemic trajectories driven by differences in the distribution of the population by age. In the African Region (median age: 18.9 years), the median R0 was 1.05 versus 2.05 in the European Region (median age: 41.7 years), and the median (per 100 persons) for the infections rate was 22.5 (versus 69.0), for severe and/or critical disease cases rate was 3.3 (versus 13.0), and for death rate was 0.5 (versus 3.9).ConclusionsAge could be a driver of variable SARS-CoV-2 epidemic trajectories worldwide. Countries with sizable adult and/or elderly populations and smaller children populations may experience large and rapid epidemics in absence of interventions. Meanwhile, countries with predominantly younger age cohorts may experience smaller and slower epidemics. These predictions, however, should not lead to complacency, as the pandemic could still have a heavy toll nearly everywhere.
Public policy and economic dynamics of COVID-19 spread: a mathematical modeling study
Authors: Goldsztejn Uri , Schwartzman David , Nehorai Arye 
Published: April 2020

AbstractWith the COVID-19 pandemic infecting millions of people, large-scale isolation policies have been enacted across the globe. To assess the impact of isolation measures on deaths, hospitalizations, and economic output, we create a mathematical model to simulate the spread of COVID-19, incorporating effects of restrictive measures and segmenting the population based on health risk and economic vulnerability. Policymakers make isolation policy decisions based on current levels of disease spread and economic damage. For 76 weeks in a population of 330 million, we simulate a baseline scenario leaving strong isolation restrictions in place, rapidly reducing isolation restrictions for non-seniors shortly after outbreak containment, and gradually relaxing isolation restrictions for non-seniors. We used 76 weeks as an approximation of the time at which a vaccine will be available. In the baseline scenario, there are 235,724 deaths and the economy shrinks by 34.0%. With a rapid relaxation, a second outbreak takes place, with 525,558 deaths, and the economy shrinks by 32.3%. With a gradual relaxation, there are 262,917 deaths, and the economy shrinks by 29.8%. We also show that hospitalizations, deaths, and economic output are quite sensitive to disease spread by asymptomatic people. Strict restrictions on seniors with very gradual lifting of isolation for non-seniors results in a limited number of deaths and lesser economic damage. Therefore, we recommend this strategy and measures that reduce non-isolated disease spread to control the pandemic while making isolation economically viable.
Onsite virtual classroom versus physical classroom: A comparative study of learning and student perception in orthopaedic training
Authors: Puthezhath Kishore 
Published: April 2020

IntroductionMore students are posted in the orthopaedic out-patient departments than before. Lack of clinical space to accommodate students is a frequently cited problem. Virtual learning allows for an adjustable location and is scalable. We aimed to compare both the effectiveness and student satisfaction level between onsite virtual classroom and physical classroom in teaching orthopaedics to a group of undergraduate medical students.MethodsA quasi-experimental non-equivalent group design study was conducted with 49 final-year medical students participating in orthopaedic training between November 2019 to January 2020. These students were randomly allocated into two groups, experimental (virtual classroom) and comparison (physical learning). The experimental group received an onsite virtual learning environment, whereas the control group received the same content in a physical classroom. Pre and post-tests that consisted of multiple choice questions were administered. At the end of the class, the students completed a 5-point Likert scale satisfaction level evaluation questionnaire.ResultsThe post-test knowledge scores between virtual classroom (M=78.2,SD=12.74) and Physical classroom (M=77.92,SD=10.31) were not different (z= 0.00, p=1.00). Though the overall perceptions of learning were positive, some frustrations were apparent and the student satisfaction was significantly better (z=-4.60, p value=0.00) with the physical classroom (M=3.83,SD=0.16) compared to virtual classroom (M=3.5,SD=0.23).ConclusionsOnsite virtual activities are not as satisfying as physical classroom in the opinion of the students, but they are successful strategies in learning that can be used in outpatient orthopaedic clinics to address the problem of lack of space. Students learn content focused on orthopaedic clinical learning objectives as well using onsite virtual classroom as they do in the traditional classroom setting.
Analysis of COVID-19 spread in South Korea using the SIR model with time-dependent parameters and deep learning
Authors: Jo Hyeontae , Son Hwijae , Hwang Hyung Ju , Jung Se Young 
Published: April 2020

AbstractMathematical modeling is a process aimed at finding a mathematical description of a system and translating it into a relational expression. When a system is continuously changing over time (e.g., infectious diseases) differential equations, which may include parameters, are used for modeling the system. The process of finding those parameters that best fit the given data from the system is called an inverse problem. This study aims at analyzing the novel coronavirus infection (COVID-19) spread in South Korea using the susceptible-infected-recovered (SIR) model. We collect the data from Korea Centers for Disease Control & Prevention (KCDC). We assume that each parameter in the SIR model is a function of time so that we can compute important parameters, such as the basic reproduction number (R0), more delicately. Using neural networks, we propose a method to find the best time-varying parameters and the solution for the model simultaneously. Moreover, using time-dependent parameters, we find that traditional numerical algorithms, such as the Runge-Kutta methods, can successfully approximate the SIR model while fitting the COVID-19 data, thus modeling the propagation patterns of COVID-19 more precisely.
The Coronavirus Disease (COVID-19) Pandemic: Simulation-Based Assessment of Outbreak Responses and Post Peak Strategies
Authors: Struben Jeroen 
Published: April 2020

AbstractIt is critical to understand the impact of distinct policy interventions to the ongoing coronavirus disease pandemic. I develop a flexible behavioral, dynamic, and sectorial epidemic policy model comprising both endogenous virus transmission and public health and citizen responses. Applicable to the full epidemic cycle including confinement, deconfinement, and resurgence, the model allows exploring the multivariate impact of distinct policy interventions, including general and targeted testing and social contact reduction efforts. Using a cross-sectional calibration to data on the ongoing coronavirus disease outbreak about reported cases and deaths, tests performed, and social interactions from six countries (South Korea, Germany, Italy, France, Sweden, and the United States), I demonstrate how early, rapid, and extensive buildup of testing and social contact reduction efforts interplay to suppress the outbreak. I then use the model to show and quantify limits to the extent of deconfinement and illustrate the critical role of targeted approaches for managing post peak deconfinement and resurgence. To aid necessary public and expert understanding of outbreak control strategies the model is accessible in the form of a web-based management flight simulator.
Initial stage of the COVID-19 infection process in human population
Authors: Trigger S.A. 
Published: April 2020

The simplest approximation for the first stages of the infection spread is considered. The specific feature of the COVID-19 characterized by its long latent period is taken into account. Exponential increase of numbers of infected people is determined by the half period of the maximal latent time for the COVID-19. The averaging over latent period leads to additional increase of the infected numbers.PACS number(s)02.50.-r, 05.60.-k, 82.39.-k, 87.19.Xx
A COVID-19 Risk Assessment for the US Labor Force
Authors: Maher Samantha , Hill Alexandra E , Britton Peter , Fenichel Eli P. , Daszak Peter , Zambrana-Torrelio Carlos , Bayham Jude 
Published: April 2020

AbstractThe consequences of COVID-19 infection varies substantially based on individual social risk factors and predisposing health conditions. Understanding this variability may be critical for targeting COVID-19 control measures, resources and policies, including efforts to return people back to the workplace. We compiled individual level data from the National Health Information Survey and Quarterly Census of Earnings and Wages to estimate the number of at-risk workers for each US county and industry, accounting for both social and health risks. Nearly 80% of all workers have at least one health risk and 11% are over 60 with an additional health risk. We document important variation in the at-risk population across states, counties, and industries that could provide a strategic underpinning to a staged return to work.One Sentence SummaryThere is important variability in the proportion of the US workforce at risk for COVID-19 complications across regions, counties, and industries that should be considered when targeting control and relief policies, and a staged return to work.
An evaluation of the fracture resistance of endodontically treated extracted teeth restored with Titanium, Carbon and Fibre posts : An in-vitro randomized control trial
Authors: Behera Sonali Suvadarsini , Choudhury Gopal Krishna , Mohapatra Abhilash , Panigrahi Sandeep Kumar 
Published: April 2020

ABSTRACTPost and core enforcement is done for Root Canal Treated (RCT) tooth as per need. Several posts and core systems are available claiming superiority. The usual post and core enforcement used in set up in India include that based on titanium and fiber. An unbiased in-vitro randomized control trial to compare the fracture resistance of RCT teeth with those restored with Titanium, Carbon and Fibre posts was hence conducted. The trial was conducted in a tertiary care dental institute in the eastern part of India. A total of 40 normal samples of extracted first mandibular were randomized to four groups (A through D) of ten samples each. Block random design was used, random number sequence was generated through computer centrally. The process was blinded, also during analysis. Group A (control) was RCT teeth with intact coronal structure while group B, C and D (interventional) were RCT teeth restored with titanium, carbon and fiber posts respectively. Universal Testing Machine (‘Tinius Olsen, H50KS’) was used for testing fracture resistance. The data were analyzed using Kruskal Wallis test followed by pairwise comparison in Stata v 12.1 SE. All statistical interpretations were done at p= 0.05 levels. The median fracture resistance among the groups was significantly different (p=0.000). Median fracture resistance of control, titanium, and fiber groups were similar (p >0.05). The median fracture resistance of the carbon group was inferior to all other groups (p<0.05). It was concluded that fiber and titanium post and core systems similar in strength to only root canal treated tooth, and scored better as compared to carbon post and core system.
Impact of lockdown on COVID-19 epidemic in Île-de-France and possible exit strategies
Authors: Domenico Laura Di , Pullano Giulia , Sabbatini Chiara E. , Boëlle Pierre-Yves , Colizza Vittoria 
Published: April 2020

ABSTRACTBackgroundMore than half of the global population is under strict forms of social distancing. Estimating the expected impact of lockdown and exit strategies is critical to inform decision makers on the management of the COVID-19 health crisis.MethodsWe use a stochastic age-structured transmission model integrating data on age profile and social contacts in Île-de-France to (i) assess the epidemic in the region, (ii) evaluate the impact of lockdown, and (iii) propose possible exit strategies and estimate their effectiveness. The model is calibrated to hospital admission data before lockdown. Interventions are modeled by reconstructing the associated changes in the contact matrices and informed by mobility reductions during lockdown evaluated from mobile phone data. Different types and durations of social distancing are simulated, including progressive and targeted strategies, with large-scale testing.ResultsWe estimate the reproductive number at 3.18 [3.09, 3.24] (95% confidence interval) prior to lockdown and at 0.68 [0.66, 0.69] during lockdown, thanks to an 81% reduction of the average number of contacts. Model predictions capture the disease dynamics during lockdown, showing the epidemic curve reaching ICU system capacity, largely strengthened during the emergency, and slowly decreasing. Results suggest that physical contacts outside households were largely avoided during lockdown. Lifting the lockdown with no exit strategy would lead to a second wave overwhelming the healthcare system, if conditions return to normal. Extensive case-finding and isolation are required for social distancing strategies to gradually relax lockdown constraints.ConclusionsAs France experiences the first wave of COVID-19 pandemic in lockdown, intensive forms of social distancing are required in the upcoming months due to the currently low population immunity. Extensive case-finding and isolation would allow the partial release of the socio-economic pressure caused by extreme measures, while avoiding healthcare demand exceeding capacity. Response planning needs to urgently prioritize the logistics and capacity for these interventions.
Population simulations of COVID-19 outbreaks provide tools for risk assessment and continuity planning
Authors: Peng Bo , Amos Christopher I. 
Published: April 2020

AbstractEssential industrial sectors, healthcare systems, and government agencies must continue operations despite the risk of COVID-19 infection. They need tools to assess risks associated with operations, so they can devise emergency plans. We developed a population-based simulator to study COVID-19 outbreaks in enclosed environments and evaluate the effectiveness of preventative measures and action plans, such as pre-dispatch quarantine and removal of symptomatic cases.AvailabilityThe simulation tool is publicly available at http://github.com/ictr/covid19-outbreak-simulator and is free for non-commercial use.
Genetic Architecture of Maize Rind Strength Revealed by the Analysis of Divergently Selected Populations
Authors: Kumar Rohit , Gyawali Abiskar , Morrison Ginnie D. , Saski Christopher A. , Robertson Daniel J. , Tharayil Nishanth , Schaefer Robert J. , Beissinger Timothy M. , Sekhon Rajandeep S. 
Published: April 2020

ABSTRACTStalk lodging, breakage of the stalk at or below the ear, causes substantial yield losses in maize. The strength of the stalk rind, commonly measured as rind penetrometer resistance (RPR), is an important contributor to stalk lodging resistance. To enhance RPR genetic architecture, we conducted selection mapping on populations developed by 15 cycles of divergent selection for high (C15-H) and low (C15-L) RPR. We also performed time-course transcriptome and metabolic analyses on developing stalks of high (Hrpr1) and low (Lrpr1) RPR inbred lines derived from the C15-H and C15-L populations, respectively. Divergent selection significantly altered allele frequencies at 3,656 and 3,412 single nucleotide polymorphisms (SNP) in the C15-H and C15-L populations, respectively. While the majority of the SNPs under selection were unique, 110 SNPs were common in both populations indicating the fixation of alleles with alternative effects. Remarkably, preferential selection on the genomic regions associated with lignin and polysaccharide biosynthesis genes was observed in C15-H and C15-L populations, respectively. This observation was supported by higher lignification and lower extractability of cell wall-bound sugars in Hrpr1 compared to Lrpr1. Tricin, a monolignol important for incorporation of lignin in grass cell walls, emerged as a key determinant of the different cell wall properties of Hrpr1 and Lrpr1. Integration of selection mapping with transcriptomics and previous genetic studies on RPR identified 40 novel candidate genes including ZmMYB31, ZmNAC25, ZmMADS1, twoPALparalogues, two lichenases,ZmEXPA2, ZmIAA41, andCaleosin. Enhanced mechanistic and genetic understanding of RPR provides a foundation for improved stalk lodging resistance.
Telomere length in young patients with acute myocardial infarction without conventional risk factors: a pilot study from a South Asian population
Authors: Gupta Mohit , Jain Vardhmaan , Miglani Manjula , Girish M. P. , Pasha Q. , Virani Salim S. , Kalra Ankur 
Published: April 2020

AbstractBackgroundMyocardial infarction (MI) in the young South Asian population is rising alarmingly. There is an urgent need to identify novel markers to aid early risk estimation. Telomeres are long known to be markers of aging, and shorter telomeres have been reported in cardiovascular diseases (CVDs). Telomeres have been shown to be involved in modulating inflammation and oxidative stresses in other diseases. We aimed to identify the association of telomere length in young MI patients.Methods & ResultsIn a case-control study of 77 subjects in each group, DNA extraction from peripheral blood leukocytes was carried out and the relative telomere length was estimated by quantitative PCR. The results were adjusted with various demographic parameters like age and gender. The correlation studies were carried out between Telomere length and lipid profile parameters (LDL, HDL, TG, TC), clinical and demographic parameters of the subjects using partial correlations.ResultsThe relative telomere length was significantly shorter in Young MI patients (31-45 years) compared to matched healthy controls (p<0.0001). Interestingly, in a gender-based comparison, the female patients had shorter telomere length (p<0.01). Correlation analysis of the length with angiographic patterns and even the lipid profile did not reveal significance (p>0.05).ConclusionOur findings reveal the presence of shorter telomere length in patients of young MI in South Asia. Higher prevalence of stress and other factors may play a role in affecting telomere length. Larger studies are needed to confirm these findings.