SARS-CoV-2 transmission in schools in Korea: nationwide cohort study

ObjectiveThere is an urgent public need to readdress the school closure strategies. We aimed to describe the epidemiology of COVID-19 in schools and school-aged children to understand their roles in transmitting SARS-CoV-2 in Korea.DesignRetrospective cohort study.SettingAll schools in KoreaPatientsAll school-aged children in Korea.InterventionsNone (observational study).Main outcome measuresIncidence rate, proportion of affected schools.ResultsBetween February and December 2020, the incidence rate was lower among school-aged children (63.2–79.8 per 100 000) compared with adults aged 19 and above (130.4 per 100 000). Household was the main route of transmission (62.3%), followed by community (21.3%) and school clusters (7.9%). Among the schools in Korea, 52% of secondary schools had COVID-19 cases, followed by 39% of primary schools and 3% of kindergartens.ConclusionsWe found that schools and school-aged children aged 7–18 years were not the main drivers of COVID-19 transmission. The major sources of transmission were households.

Analisis Lalu Lintas Ruas Jalan Denpasar-Gilimanuk Tabanan Bali Masa Pendemi Covid 19

Tabanan Regency is one of the regencies that is traversed by the main route connecting Gilimanuk-Denpasar so that the road is known as Jalan Raya Denpasar-Gilimanuk. The road is a National Road which is the main route connecting the districts in western Bali, namely Jembrana Regency, Tabanan Regency, Badung Regency and Denpasar City. In addition, with the increasing activities of the Tabanan community, especially those in the city of Tabanan who travel either to the city of Denpasar or to other areas, passing through this route which is the main route that serves transportation activities from Tabanan to Denpasar and vice versa. In this location there are many places that cause attraction, namely shopping centers, stalls and places of worship. Therefore, congestion on these roads often occurs, especially at peak hours of traffic flow (Peak Hour). This research was conducted on the performance of roads to determine the level of service. The data analysis process uses the method of calculating the Manual Kapasitas Jalan Indonesia (MKJI) 1997). The results showed that the Tabanan-Denpasar road, Jl Ahmad Yani, during the COVID-19 pandemic PPKM level 4 was obtained, the road capacity was 2,457 smp/hour, the free flow speed was 46.48 km/hour, the degree of saturation was 0.79, the light vehicle speed value was 36 km/hour with a travel time of 25 seconds. Based on the value of the degree of saturation on the Tabanan-Denpasar road, Jl Ahmad Yani during the COVID-19 pandemic PPKM level 4 of 0.79, then the level of service for the road was entered at Service level D.

Simulation of aerosol dispersion during medical examinations

The main route of transmission of the SARS-CoV2 virus has been shown to be airborne. The objective of this study is to analyze the aerosol dispersion and potential exposure to medical staff within a typical medical examination room during classical airway procedures. The multiphase simulation of the aerosol particles in the airflow is based on a Lagrangian-Eulerian approach. All simulation cases with surgical mask show partially but significantly reduced maximum dispersion distances of the aerosol particles compared to the cases without surgical mask. The simulations have shown that medical examiner are exposed to large amount of aerosol particles, especially during procedures such as laryngoscopy where the examiner's head is directly in front of the patient's face. However, exposure can be drastically reduced if the patient wears a mask which is possible for the most of the procedures studied, such as otoscopy, sonography, or anamnesis.

NAD precursors cycle between host tissues and the gut microbiome

Nicotinamide adenine dinucleotide (NAD) is an essential redox cofactor in both mammals and microbes. Here we use isotope tracing to investigate the precursors supporting NAD synthesis in the gut microbiome. We find that preferred dietary NAD precursors are absorbed in the proximal part of the gastrointestinal tract and not available to microbes in the distal gut. Instead, circulating host nicotinamide enters the gut lumen and supports gut microbiome NAD synthesis. In addition, the microbiome converts nicotinamide, originating from the host circulation, into nicotinic acid. Host tissues uptake and utilize this microbiome-derived nicotinic acid for NAD synthesis, maintaining circulating nicotinic acid levels even in the absence of dietary consumption. Moreover, the main route from oral nicotinamide riboside, a widely used nutraceutical, to host NAD is via conversion into nicotinic acid by the gut microbiome. Thus, NAD precursors cycle between the host and gut microbiome to maintain NAD homeostasis.

Transmission and Colonization of Pneumocystis jirovecii

Pneumocystis spp. was discovered in 1909 and was classified as a fungus in 1988. The species that infects humans is called P. jirovecii and important characteristics of its genome have recently been discovered. Important advances have been made to understand P. jirovecii, including aspects of its biology, evolution, lifecycle, and pathogenesis; it is now considered that the main route of transmission is airborne and that the infectious form is the asci (cyst), but it is unclear whether there is transmission by direct contact or droplet spread. On the other hand, P. jirovecii has been detected in respiratory secretions of hosts without causing disease, which has been termed asymptomatic carrier status or colonization (frequency in immunocompetent patients: 0–65%, pregnancy: 15.5%, children: 0–100%, HIV-positive patients: 20–69%, cystic fibrosis: 1–22%, and COPD: 16–55%). This article briefly describes the history of its discovery and the nomenclature of Pneumocystis spp., recently uncovered characteristics of its genome, and what research has been done on the transmission and colonization of P. jirovecii. Based on the literature, the authors of this review propose a hypothetical natural history of P. jirovecii infection in humans.

Growth Hormone Overexpression Induces Hyperphagia and Intestinal Morphophysiological Adaptations to Improve Nutrient Uptake in Zebrafish

Graphical AbstractGH overexpression increases the intestinal mass and absorptive surface area both through the direct effects of GH transgenics (up-regulating the expression of its cognate receptor and insulin-like growth factor, igf1a) and through indirect effects through an increase in the amount of food consumed. In addition, hyperphagia provides a greater amount of nutrients in the intestinal lumen and stimulates the synthesis of di- and tri-peptide transporters, which are the main route of absorption of dietary products from protein degradation.

New Tools to Support the Risk Assessment Process of Nanomaterials in the Insurance Sector

During the last decade, the use of nanomaterials, due to their multiple utilities, has exponentially increased. Nanomaterials have unique properties such as a larger specific surface area and surface activity, which may result in health and environmental hazards different from those demonstrated by the same materials in bulk form. Besides, due to their small size, they can easily penetrate through the environmental and biological barriers. In terms of exposure potential, the vast majority of studies are focused on workplace areas, where inhalation is the most common route of exposure. The main route of entry into the environment is due to indirect emissions of nanomaterials from industrial settings, as well as uncontrollable releases into the environment during the use, recycling and disposal of nano-enabled products. Accidental spills during production or later transport of nanomaterials and release from wear and tear of materials containing nanomaterials may lead to potential exposure. In this sense, a proper understanding of all significant risks due to the exposure to nanomaterials that might result in a liability claim has been proved to be necessary. In this paper, the utility of an application for smartphones developed for the insurance sector has been validated as a solution for the analysis and evaluation of the emerging risk of the application of nanotechnology in the market. Different exposure scenarios for nanomaterials have been simulated with this application. The results obtained have been compared with real scenarios, corroborating that the use of novel tools can be used by companies that offer risk management in the form of insurance contracts.

Environmental Attributes Review of Muara Angke Fish Market and Auction, Jakarta, Indonesia

Environmental attributes as a design quality assessment material have been put forward since 1980. Muara Angke Fish Market and Auction is the largest fish auction facility in Indonesia. Its development has received attention from the community for a long time. This article intends to examine the quality of the Muara Angke design by using environmental attributes proposed by Weisman in 1980. The study was conducted by first determining the attributes to be used, namely activity, accessibility, and sociality. The research method is descriptive qualitative by examining these three aspects at Muara Angke Fish Market and Auction. Market facilities and fish auction in Muara Angke are considered feasible in terms of activities and sociality. However, accessibility needs to be improved. The combination of one-door access and linear circulation is suitable to reach all points, but the absence of distribution of circulation paths between sellers, buyers, and goods makes the main route congested, especially in the active phase of the market, namely at night.Keywords: Activity, Accessibility, Environmental Attributes, Muara Angke Fish Market and Auction, Sociality

Pharmacokinetics in Zebrafish Embryos (ZFE) Following Immersion and Intrayolk Administration: A Fluorescence-Based Analysis

Zebrafish embryos (ZFE) have increasingly gained in popularity as a model to perform safety screenings of compounds. Although immersion of ZFE is the main route of exposure used, evidence shows that not all small molecules are equally absorbed, possibly resulting in false-negative readouts and incorrect conclusions. In this study, we compared the pharmacokinetics of seven fluorescent compounds with known physicochemical properties that were administered to two-cell stage embryos by immersion or by IY microinjection. Absorption and distribution of the dyes were followed at various timepoints up to 120 hpf by spatiotemporal fluorescence imaging. The concentration (10 µM) and dose (2 mg/kg) used were selected as quantities typically applied in preclinical experiments and zebrafish studies. The data show that in the case of a lipophilic compound (log D: 1.73) the immersion procedure resulted in an intrabody exposure which is similar or higher than that seen after the IY microinjection. In contrast, zero to low intrabody exposure was reached after immersion of the embryos with less lipophilic compounds. In the latter case IY microinjection, a technical procedure that can be easily automated, is highly recommended.