scholarly journals Detection of SARs-CoV-2 in wastewater, using the existing environmental surveillance network: An epidemiological gateway to an early warning for COVID-19 in communities

2020 ◽  
Author(s):  
Salmaan Sharif ◽  
Aamer Ikram ◽  
Adnan Khurshid ◽  
Muhammad Salman ◽  
Nayab Mehmood ◽  
...  
Keyword(s):  
Early Warning ◽  
High Speed ◽  
Sequence Data ◽  
Rna Extraction ◽  
Study Finding ◽  
Warning Signs ◽  
Virus Concentration ◽  
Two Phase ◽  
Surveillance Network ◽  
Wastewater Samples

AbstractBackgroundThe ongoing COVID-19 pandemic caused by SARs-CoV-2 was transmitted person to person via droplet infections and fecal-oral transmission. This illustrates the probability of environmentally facilitated transmission, mainly the sewage.MethodWe used existing Pakistan polio environment surveillance network to investigate presence of SARs-CoV-2 using three commercially available kits and E-Gene detection published assay for surety and confirmatory of positivity. A Two-phase separation method is used for sample clarification and concentration. An additional high-speed centrifugation (14000Xg for 30 min) step was introduced, prior RNA extraction, to increase viral RNA yield resulting a decrease in Cq value.ResultsA total of 78 wastewater samples collected from 38 districts across Pakistan, 74 wastewater samples from existing polio environment surveillance sites, 3 from drains of COVID-19 infected areas and 1 from COVID 19 quarantine center drainage, were tested for presence of SARs-CoV-2. 21 wastewater samples (27%) from 13 districts turned to be positive on RT-qPCR. SARs-COV-2 RNA positive samples from areas with COVID patients and COVID 19 patient quarantine center drainage strengthen the findings and use of wastewater surveillance in future. Furthermore, sequence data of partial ORF 1a generated from COVID 19 patient quarantine center drainage sample also reinforce our findings that SARs-CoV-2 can be detected in wastewater.DiscussionThis study finding indicates that SARs-CoV-2 detection through wastewater surveillance has an epidemiologic potential that can be used as early warning system to monitor viral tracking and circulation in cities with lower COVID-19 disease burden or heavily populated areas where door-to-door tracing may not be possible. However, attention needed on virus concentration and detection assay to increase the sensitivity. Development of highly sensitive assay will be an indicator for virus monitoring and to provide early warning signs.

scholarly journals Detection of SARs-CoV-2 in wastewater using the existing environmental surveillance network: A potential supplementary system for monitoring COVID-19 transmission

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0249568
Author(s):  
Salmaan Sharif ◽  
Aamer Ikram ◽  
Adnan Khurshid ◽  
Muhammad Salman ◽  
Nayab Mehmood ◽  
...  
Keyword(s):  
High Speed ◽  
Sequence Data ◽  
Close Contact ◽  
Rna Extraction ◽  
Study Finding ◽  
Warning Signs ◽  
Virus Concentration ◽  
Two Phase ◽  
Surveillance Network ◽  
Wastewater Samples

The ongoing COVID-19 pandemic is caused by SARs-CoV-2. The virus is transmitted from person to person through droplet infections i.e. when infected person is in close contact with another person. In January 2020, first report of detection of SARS-CoV-2 in faeces, has made it clear that human wastewater might contain this virus. This may illustrate the probability of environmentally facilitated transmission, mainly the sewage, however, environmental conditions that could facilitate faecal oral transmission is not yet clear. We used existing Pakistan polio environment surveillance network to investigate presence of SARs-CoV-2 using three commercially available kits and E-Gene detection published assay for surety and confirmatory of positivity. A Two-phase separation method is used for sample clarification and concentration. An additional high-speed centrifugation (14000Xg for 30 min) step was introduced, prior RNA extraction, to increase viral RNA yield resulting a decrease in Cq value. A total of 78 wastewater samples collected from 38 districts across Pakistan, 74 wastewater samples from existing polio environment surveillance sites, 3 from drains of COVID-19 infected areas and 1 from COVID 19 quarantine center drainage, were tested for presence of SARs-CoV-2. 21 wastewater samples (27%) from 13 districts turned to be positive on RT-qPCR. SARs-COV-2 RNA positive samples from areas with COVID 19 patients and quarantine center strengthen the findings and use of wastewater surveillance in future. Furthermore, sequence data of partial ORF 1a generated from COVID 19 patient quarantine center drainage sample also reinforce our findings that SARs-CoV-2 can be detected in wastewater. This study finding indicates that SARs-CoV-2 detection through wastewater surveillance has an epidemiologic potential that can be used as supplementary system to monitor viral tracking and circulation in cities with lower COVID-19 testing capacity or heavily populated areas where door-to-door tracing may not be possible. However, attention is needed on virus concentration and detection assay to increase the sensitivity. Development of highly sensitive assay will be an indicator for virus monitoring and to provide early warning signs.

scholarly journals SARS-CoV-2 RNA in urban wastewater samples to monitor the COVID-19 epidemic in Lombardy, Italy (March - June 2020)

2021 ◽  
Author(s):  
Sara Castiglioni ◽  
Silvia Schiarea ◽  
Laura Pellegrinelli ◽  
Valeria Primache ◽  
Cristina Galli ◽  
...  
Keyword(s):  
Virus Concentration ◽  
Urban Wastewater ◽  
Surveillance Network ◽  
Lombardy Region ◽  
Viral Loads ◽  
One Step ◽  
Wastewater Samples ◽  
Asymptomatic Individuals ◽  
Viral Surveillance ◽  
Virological Surveillance

Wastewater-based viral surveillance is a promising approach to monitor the circulation of SARS-CoV-2 in the general population. The aim of this study was to develop an analytical method to detect SARS-CoV-2 RNA in urban wastewater, to be implemented in the framework of a surveillance network in the Lombardy region (Northern Italy). This area was the first hotspot of COVID-19 in Europe. Composite 24h samples were collected weekly in eight cities from end-March to mid-June 2020 (first peak of the epidemic). The method developed and optimized, involved virus concentration, using PEG centrifugation, and one-step real-time RT-PCR for analysis. SARS-CoV-2 RNA was identified in 65 (61%) out of 107 samples, and the viral concentrations (up to 2.1 E +05 copies/L) were highest in March-April. By mid-June, wastewater samples tested negative in all the cities. Viral loads were used for inter- city comparison and Brembate, Ranica and Lodi had the highest. The pattern of decrease of SARS-CoV-2 in wastewater was closely comparable to the decline of active COVID-19 cases in the population, reflecting the effect of lock-down. Wastewater surveillance of SARS-CoV-2 can integrate ongoing virological surveillance of COVID-19, providing information from both symptomatic and asymptomatic individuals, and monitoring the effect of health interventions.

scholarly journals First Data-Set on SARS-CoV-2 Detection for Istanbul Wastewaters in Turkey

2020 ◽  
Author(s):  
Bilge Alpaslan Kocamemi ◽  
Halil Kurt ◽  
Sabri Hacıoglu ◽  
Cevdet Yaralı ◽  
Ahmet Mete Saatci ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Warning Signs ◽  
Virus Concentration ◽  
Serum Samples ◽  
Data Set ◽  
Concentration Method ◽  
Diagnostic Panel ◽  
Wastewater Samples

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started in Wuhan, China, in December 2019 and became a global pandemic [1]. By 26 April 2020, more than 2.9 million people were infected by SARS-CoV-2 and over 203 thousand people lost their life globally. By 26 April 2020, 107773 confirmed cases were reported in Turkey with 2706 deaths. Majority of the cases in Turkey has been observed in Istanbul. In the world, the duration of availability of SARS-CoV-2 was found to be significantly longer in stool samples than in respiratory and serum samples [2]. SARS-CoV-2 was detected in wastewaters in Australia [3], Netherlands [4], USA [5], France [6], Spain [7] and USA [8] by using different virus concentration techniques. In this work, Istanbul metropole with 65 % of Covid-19 cases was chosen as the pilot city. On the 21st of April 2020, 24-hr composite samples were collected from the Ambarli, Pasakoy and Kadikoy wastewater treatment plants (WWTP). On the 25th of April 2020, more wastewater samples were taken from Terkos, Buyukcekmece, Baltalimani and Tuzla WWTPs. These wastewater treatment plants were selected among 81 plants in Istanbul in order to take representative samples from 4 different districts of Istanbul according to the severity of Covid-19 cases, like very serious, serious, moderate and mild. Grab samples were also collected from Bagcilar and Kartal manholes located nearby the pandemic hospitals on April 21st, 2020. Polyethylene glycol 8000 (PEG 8000) adsorption [5] SARS-Cov-2 concentration method was used for SARS-CoV-2 concentration after optimization. Real time RT-PCR diagnostic panel validated by US was used to quantify SARS-CoV-2 RNA in raw sewage taken from the inlets of treatment plants and manholes. Five samples out of seven from wastewater and all samples from manholes were tested positive. SARS-CoV-2 in raw sewage from Ambarli, Pasakoy, Kadikoy, Terkos, Buyukcekmece, Baltalimani and Tuzla WWTPs were found as 8.26×103, 1.80×104, ND, ND, 3.73×103, 4.95×103, 2.89×103, respectively. The Bagcilar and Kartal manholes nearby pandemic hospitals exhibited 4.49×104 and 9.33×104, respectively. SARS-CoV-2 virus titers of manhole were higher than those of inlet of WWTPs. The observed copy numbers were presented against the number of Covid-19 cases coming to the WWTP per treatment plant capacity. Quantitative measurements of SARS-CoV-2 in wastewater can be used as a tool in wastewater-based epidemiology (WBE) and it can provide information about SARS-CoV-2 distribution in wastewater of various districts of Istanbul which exhibit different scores of Covid-19 cases. The distribution of epidemy was followed not only with blood test but with wastewater monitoring. This may allow us to identify the districts not exhibiting many Covid-19 cases, but under high risk. Continuous monitoring of wastewater for SARS-Cov-2 may provide an early warning signs before an epidemy starts in case of infection resurge.

scholarly journals Wastewater sequencing uncovers early, cryptic SARS-CoV-2 variant transmission

2021 ◽  
Author(s):  
Smruthi Karthikeyan ◽  
Joshua I Levy ◽  
Peter De Hoff ◽  
Greg Humphrey ◽  
Amanda Birmingham ◽  
...  
Keyword(s):  
Sequence Data ◽  
Virus Concentration ◽  
Clinical Testing ◽  
University Campus ◽  
Infection Dynamics ◽  
Abundance Estimates ◽  
Two Factors ◽  
Critical Issues ◽  
Multiple Virus ◽  
Wastewater Samples

As SARS-CoV-2 becomes an endemic pathogen, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here, we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We develop and deploy improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detect emerging variants of concern up to 14 days earlier in wastewater samples, and identify multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

Two-Phase Short Circuit in the Power Grid Powered by a Transformer with a Y/Δ-11 Winding Connection

2020 ◽  
pp. 25-30
Author(s):  
Aleksandr S. Serebryakov ◽  
Vladimir L. Osokin ◽  
Sergey A. Kapustkin
Keyword(s):  
High Speed ◽  
Short Circuit ◽  
Relay Protection ◽  
Electric Circuit ◽  
Operational Reliability ◽  
Research Purpose ◽  
Industrial Complex ◽  
Two Phase ◽  
Short Circuit Currents ◽  
Secondary Winding

The article describes main provisions and relations for calculating short-circuit currents and phase currents in a three-phase traction transformer with a star-triangle-11 connection of windings, which feeds two single-phase loads in AC traction networks with a nominal voltage of 25 kilovolts. These transformers provide power to the enterprises of the agro-industrial complex located along the railway line. (Research purpose) The research purpose is in substantiating theoretical equations for digital intelligent relay protection in two-phase short circuits. (Materials and methods) It was found that since the sum of instantaneous currents in each phase is zero, each phase of the transformer works independently. We found that this significantly simplifies the task of analyzing processes with a two-phase short circuit. In this case, the problem of calculating short-circuit currents in the traction network can be simplified by reducing it to the calculation of an ordinary electric circuit with three unknown currents. (Results and discussion) The article describes equations for calculating short-circuit resistances for one phase of the transformer when connecting the secondary winding as a star or a triangle. The currents in the phases of the transformer winding at short circuit for the star-triangle-11 and star-star-with-ground schemes are compared. It was found that when calculating short-circuit currents, there is no need to convert the secondary winding of the traction transformer from a triangle to a star. (Conclusions) It was found that the results of the research can be used in the transition of relay protection systems from electromagnetic relays to modern high-speed digital devices, which will increase the operational reliability of power supply systems for traction and non-traction power consumers.

scholarly journals Development and validation of an early warning tool for sepsis and decompensation in children during emergency department triage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Louis Ehwerhemuepha ◽  
Theodore Heyming ◽  
Rachel Marano ◽  
Mary Jane Piroutek ◽  
Antonio C. Arrieta ◽  
...  
Keyword(s):  
Emergency Department ◽  
Severe Sepsis ◽  
Early Warning ◽  
Characteristic Curve ◽  
Vital Signs ◽  
Warning System ◽  
Receiver Operator Characteristic Curve ◽  
Warning Signs ◽  
Gradient Boosting ◽  
Stochastic Gradient Boosting

AbstractThis study was designed to develop and validate an early warning system for sepsis based on a predictive model of critical decompensation. Data from the electronic medical records for 537,837 visits to a pediatric Emergency Department (ED) from March 2013 to December 2019 were collected. A multiclass stochastic gradient boosting model was built to identify early warning signs associated with death, severe sepsis, non-severe sepsis, and bacteremia. Model features included triage vital signs, previous diagnoses, medications, and healthcare utilizations within 6 months of the index ED visit. There were 483 patients who had severe sepsis and/or died, 1102 had non-severe sepsis, 1103 had positive bacteremia tests, and the remaining had none of the events. The most important predictors were age, heart rate, length of stay of previous hospitalizations, temperature, systolic blood pressure, and prior sepsis. The one-versus-all area under the receiver operator characteristic curve (AUROC) were 0.979 (0.967, 0.991), 0.990 (0.985, 0.995), 0.976 (0.972, 0.981), and 0.968 (0.962, 0.974) for death, severe sepsis, non-severe sepsis, and bacteremia without sepsis respectively. The multi-class macro average AUROC and area under the precision recall curve were 0.977 and 0.316 respectively. The study findings were used to develop an automated early warning decision tool for sepsis. Implementation of this model in pediatric EDs will allow sepsis-related critical decompensation to be predicted accurately after a few seconds of triage.

Journey towards best practices in acting on early warning signs in complex projects within a Russian context

2015 ◽  
Vol 8 (4) ◽  
pp. 828-843 ◽  
Author(s):  
Gulnara Sharaborova ◽  
Derek H.T. Walker ◽  
Guinevere Gilbert
Keyword(s):  
Early Warning ◽  
Point Of View ◽  
Warning Signs ◽  
Theory And Practice ◽  
Doctoral Study ◽  
Content Type ◽  
Early Warning Signs ◽  
Complex Projects ◽  
Research Findings ◽  
Phd Thesis

Purpose – The purpose of this paper is to provide a summary report and reflect on a recently passed PhD thesis (Sharaborova, 2014b) related to project management topics. Design/methodology/approach – This paper focussed on narrative reflection upon the completed doctoral journey. Findings – This paper presents the thesis findings, the research models, the guide in dealing with the early warning signs that developed as a result of this research and the contribution made to theory and practice. Research limitations/implications – Limitations of the research and the perspectives of the further diffusion of the research findings are considered. Originality/value – This TRN is a PhD candidate’s point of view as well as the opinions of the scientific research supervisors about the doctoral study and its outcome. The paper could be useful for novice researchers who wish to conduct their research and did not yet make a decision.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Experimental Characterization of a Modified Airlift Pump

2014 ◽  
Author(s):  
Afshin Goharzadeh ◽  
Keegan Fernandes
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
High Speed ◽  
Water Flow Rate ◽  
High Speed Photography ◽  
Two Phase ◽  
Inner Diameter ◽  
Airlift Pump ◽  
Flow Map ◽  
Churn Flow

This paper presents an experimental investigation on a modified airlift pump. Experiments were undertaken as a function of air-water flow rate for two submergence ratios (ε=0.58 and 0.74), and two different riser geometries (i) straight pipe with a constant inner diameter of 19 mm and (ii) enlarged pipe with a sudden expanded diameter of 19 to 32 mm. These transparent vertical pipes, of 1 m length, were submerged in a transparent rectangular tank (0.45×0.45×1.1 m3). The compressed air was injected into the vertical pipe to lift the water from the reservoir. The flow map regime is established for both configurations and compared with previous studies. The two phase air-water flow structure at the expansion region is experimentally characterized. Pipeline geometry is found to have a significant influence on the output water flow rate. Using high speed photography and electrical conductivity probes, new flow regimes, such as “slug to churn” and “annular to churn” flow, are observed and their influence on the output water flow rate and efficiency are discussed. These experimental results provide fundamental insights into the physics of modified airlift pump.

Effect of Pressure on Bubble Growth Within Liquid Droplets at the Superheat Limit

1982 ◽  
Vol 104 (4) ◽  
pp. 750-757 ◽  
Author(s):  
C. T. Avedisian
Keyword(s):  
Vapor Bubble ◽  
Bubble Growth ◽  
High Speed ◽  
Ambient Pressure ◽  
Organic Liquid ◽  
Liquid Droplets ◽  
Growth Data ◽  
Two Phase ◽  
Photographic Evidence ◽  
Good Agreement

A study of high-pressure bubble growth within liquid droplets heated to their limits of superheat is reported. Droplets of an organic liquid (n-octane) were heated in an immiscible nonvolatile field liquid (glycerine) until they began to boil. High-speed cine photography was used for recording the qualitative aspects of boiling intensity and for obtaining some basic bubble growth data which have not been previously reported. The intensity of droplet boiling was found to be strongly dependent on ambient pressure. At atmospheric pressure the droplets boiled in a comparatively violent manner. At higher pressures photographic evidence revealed a two-phase droplet configuration consisting of an expanding vapor bubble beneath which was suspended a pool of the vaporizing liquid. A qualitative theory for growth of the two-phase droplet was based on assuming that heat for vaporizing the volatile liquid was transferred across a thin thermal boundary layer surrounding the vapor bubble. Measured droplet radii were found to be in relatively good agreement with predicted radii.

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