Prevention Of Contamination Research Articles

Characterization of the broad-spectrum phage vB_CsaM_CBT2 and its inhibition of multidrug-resistant Cronobacter sakazakii in powered infant formula

Cronobacter is a group of foodborne pathogens linked to serious and deadly infections in newborns and babies through the consumption of contaminated powdered infant formula (PIF). Meanwhile, antimicrobial misuse has led to emergence of multi-drug resistant (MDR) Cronobacter strains, affecting food safety. Here, a lytic phage vB_CsaM_CBT2 (CBT2) was isolated from a wastewater treatment plant in Hefei as an effective antimicrobial alternative to antibiotics. Phage CBT2 has a broad host spectrum. It can target and lyse 17 strains including MDR clinical strain C. sakazakii GZcsf-1 from four species of C. sakazakii, C. turicensis, C. muytjensii and C. condimenti in the genus Cronobacter. Some Cronobacter phages have a narrow host range and have only been confirmed to infect a single strain of Cronobacter. In addition, excellent tolerance to temperature (25 °C–70 °C) and pH values (3-11) of phage CBT2 were determined. Based on genomic and phylogenetic analyses, the phage CBT2 was successfully identified belonging to the Straboviridae, and genes related with drug resistance and virulence were not observed. After treatment of the phage CBT2 in four brands of rehydrated PIF, the viable counts of host bacteria (C. sakazakii GZcsf-1) were reduced 3.0 log CFU/mL (＞99.9%) after 6 h at 37 °C. The findings in this study provided an alternative tool for prevention and control of Cronobacter contamination in PIF.

BD Chloraprep™ (“2 % chlorhexidine with 70 % isopropyl alcohol”) versus povidone iodine plus alcohol, for prevention of blood culture contamination at children: An investigator-initiated, open-label, single centre, randomized controlled trial

IntroductionOne of the important problems that lower the diagnostic value of blood culture is contamination with skin organisms. The povidone-iodine, alcohol, and chlorhexidine gluconate alcohol are used for disinfection prior to blood sampling for culture. MethodsThe investigator-initiated, open label, single centre, randomised trial compared blood culture contamination rates between two groups of patients in which using a povidone iodine skin-preparation process with the contamination rate for using “2 % chlorhexidine with 70 % isopropyl alcohol” skin-disinfection. The patients who required sampling for blood cultures were included in the study and study period was from 15 March 2023 to 15 July 2023. ResultsA total of 400 blood cultures were obtained during the study, including 133 in the study group and 267 in the control group. In the total blood cultures, 11.75 % (n = 47) had microorganism isolation. Among them 39 (9.75 %) were contaminants and 8 (2 %) of them were true pathogens. The contaminant microorganisms were as following; 34 coagulase-negative Staphylococci, 3 Micrococcus spp, and 2 Streptococci viridans. The blood culture contamination rate in the study group was 5.3 % (n = 7) and 12.0 % (n = 32) in the control group, and significantly lower in the study group (p = 0.033). There is no significant difference regarding skin related side effects between two groups. ConclusionsThis study, showed that 2 % chlorhexidine gluconate in 70 % isopropyl alcohol is more efficacious in children than 10 % povidone-iodine preparations for disinfecting the skin prior to blood specimen collection for prevention of blood culture contamination.

Quantification and visualization of groundwater contamination prevention regionalization based on analytic hierarchy process method (AHP) in Guangdong-Hong Kong-Macao Greater Bay Area, South China

The groundwater contamination assessment and prevention regionalization are an important part of groundwater investigation, which is of great significance to groundwater environmental management and contamination control. Although the Guangdong-Hong Kong-Macao Greater Bay Area (GHM Greater Bay Area) has faced significant groundwater contamination since 2020, there's been no investigation into its vulnerability zonation. In this paper, groundwater in a typical area of south China was taken as the research object. We analyzed groundwater contamination risk by considering both the groundwater vulnerability and the load from contamination sources. Using the analytic hierarchy process (AHP) method, we superposed the groundwater risk, function value and contamination status, and realized the quantification and visualization of groundwater contamination prevention regionalization. Based on the DRASTIC model, the zones of low, moderate, high, and very high vulnerability are respectively 14.2 %, 24.28 %, 37.67 %, and 20.45 % of the study area. Results show that the groundwater vulnerability grade in the area is III-IV, which means it is easy to be polluted. The functional value of groundwater in the south-central part of the region is relatively high. Most of the areas with high prevention and control levels are located in plain areas and the Piedmont plain area with an area of 460 km2. The secondary control levels (key protection area) are mainly located in the middle, southwest, and northeast of the plain, with an area of 6944 square kilometers. Consequently, the ideas and contamination prevention zone maps might provide a scientific foundation for long-term planning and management and groundwater conservation in the Guangdong-Hong Kong-Macao Greater Bay Area and peripheral zones.

Mechanism Underlying Bacillus subtilis BS-Z15 Metabolite-Induced Prevention of Grain Contamination by Aspergillus flavus.

Aspergillus flavus can cause mildew in corn, peanuts, and other foods as well as animal feed, which seriously endangers human and livestock health; thus, preventing A. flavus contamination is imperative. Previous studies have found that the secondary metabolites of Bacillus subtilis BS-Z15 have broad-spectrum-inhibiting fungal activity, further confirming that the main active inhibiting fungal substance is Mycosubtilin (Myco). In this paper, corn and peanuts were treated with 0, 100, and 200 μg/mL BS-Z15 secondary metabolites (BS-Z15-SMA) for 7 days, and the aflatoxin contamination prevention effect was examined. The results showed that with increasing BS-Z15-SMA concentration, the aflatoxin contamination prevention effect was significantly enhanced. The above toxicity phenomena became more significant with extended BS-Z15-SMA treatment time. Scanning electron microscopy showed that 4 μg/mL Myco treatment resulted in a dented A. flavus surface and breakage of both the conidial stem and the mycelium. Transcriptome results showed that Myco significantly affected gene expression in A. flavus spores. The downregulated genes were significantly enriched in cell wall synthesis, transcription and translation, transmembrane transport pathways, and pathways related to key enzymes for aflatoxin synthesis. These results suggest that Myco could be used as a new bioactive material to prevent aflatoxin synthesis and contamination.

Determination of degradation/reaction rate for surface water quality of recycled water using Lake2K model for large-scale water recycling.

The depletion of groundwater resources in the water-stressed regions has led to the overuse of surface water reservoirs. Recharging groundwater by rejuvenating dried surface reservoirs using recycled water is a new sustainable solution. To ensure the prevention of groundwater contamination and associated health risks (as recycled water is used), it is crucial to assess the surface reservoir water quality. The study for the first time suggests the Lake2K model, a one-dimensional mechanistic mass-balance model, to simulate the changes in water quality in a series of man-made surface water reservoirs where recycled water flows under an indirect groundwater recharge scheme (soil aquifer treatment system). The model was developed, calibrated, and validated using field observations to estimate degradation/reaction rate constants for various water quality parameters. The observed average degradation/reaction rate constants for parameters including ammonia-N, nitrate-N, total nitrogen, total organic carbon, and organic phosphorous were 0.043day-1, 0.04day-1, 0.043day-1, 0.055day-1, and 0.056day-1, respectively, which were found to be relatively high compared to existing literature, indicating a greater degradation of these parameters in warmer climates. The results showed that the water quality improved significantly as the water progressed through the reservoirs, aligning with field observations. Additionally, the simulated seasonal variations revealed that the maximum growth rate of phytoplankton occurred during July, August, and September for each reservoir, while the nutrient pool (nitrate-N and orthophosphates) experienced the greatest depletion during this growth period. These findings shed light on the dynamics of surface water quality in regions facing water scarcity and contribute to the development of sustainable groundwater management strategies.

ASSESSMENT OF HEAVY METALS IN READY-TO-EAT (RTE) VEGETABLES SALADS SOLD WITHIN KANO METROPOLIS, NIGERIA

Ready-to-eat (RTE) salads prepared from leafy vegetables sold in the streets are now common in Kano metropolis due to their convenience and acceptance by consumers. Due to the unhygienic environmental conditions and other condiments used in its preparation, vegetable salad could be contaminated with heavy metals. This study aimed to determine heavy metals safety of RTE salads hawked in Kano metropolis, Kano state, Nigeria. Forty samples of RTE salads were purposely purchase from eight local government areas of Kano metropolis and were analyzed for the presence of Cd, Cr, Hg and Pb using Atomic Absorption Spectrophotometer. The results of the analysis showed the concentration of Hg (3.208 - 1.220 mg/kg), Cr (0.756 - 0.212 mg/kg), Pb (0.392 - 0.036 mg/kg) and Cd (0.056 - 0.044). It was therefore concluded that vegetable salad sold in Kano metropolis are prone to public health concerns since the levels of Hg, Cr and Pb were found to be above the permissible limits of 0.01, 0.1 and 0.1 (for leafy vegetables) ratified by the Codex Alimentarius Commission. Thus, prevention of heavy metals contamination in vegetables salads is necessary, this will help in prevention of acute and chronic health problems due to exposure to heavy metals from consuming street vended RTE vegetables salads in this region.

Saliva Collection Methods: A Comprehensive Guide for Scientific Research

Saliva has recently emerged as a valuable biological fluid in scientific research due to its rich biochemical composition and non-invasive accessibility. This article aims to provide a comprehensive guide to saliva collection methods in scientific research, covering procedures, materials, contamination prevention, storage protocols, collection methods, clinical trial considerations, and sample stabilization. By adhering to meticulous protocols, researchers can ensure the accuracy and reliability of their findings, thus maximizing the potential of saliva as a biospecimen for various research applications. The detailed exploration of each aspect of saliva collection methods in this article will help researchers optimize their collection and handling techniques, ensuring accurate and reliable results that will contribute to scientific knowledge.

Training in tools to develop quantitative microbial risk assessment of ready-to-eat food with a comparison between the Romanian and Spanish food supply chains.

The prevention and control of bacterial contamination on ready-to-eat (RTE) fresh produce is an essential task to ensure food safety. Therefore, the development of novel and effective decontamination technologies to ensure microbiological safety of fruits and vegetables has gained considerable attention and new sanitisation methods are needed. The antimicrobial activity of essential oils (EOs) is well documented, but their application in fresh produce remains a challenge due to their hydrophobic nature. Thus, nanoemulsions efficiently contribute to support the use of EOs in foods by enhancing their dispersibility, their contact area and facilitating the introduction into bacterial cells. The combination of these factors ultimately increases their antimicrobial activity. Quantitative microbial risk assessment (QMRA) is gaining more attention as an effective tool to assess and prevent potential risks associated with food-borne pathogens. In this context, the current project aims to study the effectiveness of different washing methods based on nanoemulsified EOs, comparing them against traditional methods, using a QMRA model for Escherichia coli O157:H7 on cherry tomatoes. Different simulations within a stochastic risk assessment model were implemented using the biorisk package for R, aiming to describe microbial behaviour and biological risk along the Romanian and Spanish food supply chains of RTE fresh produce. Nanoemulsions were prepared using oregano and rosemary EOs, each from Romania and Spain. The four nanoemulsions were evaluated as decontamination treatments to control the growth of E. coli O157:H7 on artificially contaminated cherry tomatoes. The decontamination treatments showed encouraging results, comparable to commonly used chlorine solutions. Therefore, oregano and rosemary nanoemulsions are promising and could be a feasible alternative for chlorine solutions in the reduction of microbiological contaminants.

Prevention, Diagnosis and Eradication of Mycoplasma Contamination in Cell Culture.

Mycoplasmas, which are the smallest and simplest prokaryotes, lack a cell wall but possess the ability to undergo self-replication. Mycoplasma contamination is a common problem for laboratories engaging in cell culture. Due to their small size, Mycoplasmas can easily permeate filters designed to prevent bacterial and fungal contamination in cell culture. Although Mycoplasma contamination usually does not result in cell death, it can significantly affect cell proliferation, metabolism, and cause chromosomal aberrations. Therefore, it is crucial to detect and eliminate Mycoplasma contamination in cell culture. This step-by-step protocol presents a comprehensive approach to prevent Mycoplasma contamination in cell culture, as well as to detect and eradicate Mycoplasma to ensure accurate experimental and sequencing results.

Влияние природного выщелачивания руд на заболеваемость населения селитебных территорий

The problem of prevention of contamination of the residential area of metal mines by extracting metals from natural leaching solutions to reduce the incidence of residents is considered. Quantitative indicators are presented concerning the pollution of residential areas with natural leaching products. It is proposed to extract toxic metals from the liquid leaching products as they reach the earth surface. The mechanism of environmental degradation as a result of the activities of the enterprises of the Sadon lead-zinc plant is detailed. It is shown that the phenomenon of extraction of metals from natural and technological solutions can be used in the implementation of environmental protection processes. The results of the application of geotechnological methods of metal production in the North Caucasus are summarized. The contribution of scientists from the North Caucasus Mining and Metallurgical Institute to the theory and practice of metal leaching is noted. The program of technological and medical research was developed, and the results of comprehensive studies of the morbidity of mine workers and residents of residential areas depending on the distance from the source of pollution are presented. An algorithm for the organization of preventive leaching of ores left in the worked-out space is proposed. It is proved that the chemical impact of natural leaching of ore mining and processing products on the population of residential areas is the cause of technogenic metal-induced toxicity and is accompanied by an increase in diseases. It is substantiated that a radical measure to prevent progressive morbidity is the preventive extraction of metals from ore processing tailings and mine wastewater. It is shown that the extraction of metals from the products of their activities helps to reduce environmental damage and morbidity among employees of mining enterprises and the population of residential areas.

A Review of the Status, Effects, Prevention, and Remediation of Groundwater Contamination for Sustainable Environment

Most water systems that support ecosystems and feed humans are depleted or stressed. Aquifer characteristics, topography, subsurface activities, climate, and geochemical processes regulate groundwater availability, a reliable source of fresh water. Globally, agriculture, industries, and the domestic sector are the three major sectors that consume vast quantities of freshwater resources. Further anthropogenic activities, such as soil leaching, acid rain, fertilizer, pesticides, mining, and other industrial activities, resulted in the release of organic and inorganic pollutants that affected global water resources. In India, groundwater is used in huge quantities, resulting in groundwater depletion of 1 to 2 m a year. Low-income countries face many issues related to water pollution, and the availability of safe water is minimal. In 2019, deaths due to unsafe sanitation accounted for 2.2% of the total global deaths, amounting to 1.2 million people’s deaths. India recorded 6.6% of deaths due to unsafe sanitation in 2019. India and China accounted for around 90.41% and 60.4% of the groundwater utilization for agricultural purposes, respectively. In 2020, China and India utilized vast quantities of nutrients (nitrate and phosphate) for crop growth to enhance crop yield, resulting in the highest nitrate and phosphate concentrations in groundwater. Remediating contaminants from different sources requires knowledge of their concentration, behavior, cycling, and degradation pathways. According to safety guidelines, limiting and optimizing crop organic and inorganic fertilizer, pesticide waste disposal, and empty container disposal can reduce groundwater contamination. The present study summarized groundwater utilization in various sectors, potential sources of groundwater contamination impacts on human health and the environment, preventive measures, and mitigation methods to overcome groundwater pollution.

Restaurant and Staff Characteristics Related to Practices that Could Contribute to Cross-Contamination

Foodborne illness is a persistent public health concern in the U.S.; over 800 foodborne illness outbreaks are reported to the Centers for Disease Control and Prevention (CDC) annually. Most of these outbreaks (60%) are linked with restaurants. Contamination of food with foodborne pathogens during preparation and storage is a significant contributing factor to many of these outbreaks. The CDC’s Environmental Health Specialists Network (EHS-Net) collected data to identify restaurant characteristics, policies, and practices associated with contamination prevention practices. Data collectors interviewed managers and conducted kitchen observations in 312 restaurants across six EHS-Net sites in five states. Data collectors observed at least one food worker action that could lead to contamination in 63.1% of restaurants. The most frequently observed action that could lead to contamination was bare-hand or dirty glove contact with ready-to-eat food (35.9%). The estimated mean number of observed potential contamination actions was greater in restaurants that were independently owned (does not share a name and operations with other restaurants), did not require managers to be certified in food safety, did not have workers trained in food safety, did not have a handwashing policy, did not have a policy minimizing bare-hand contact with ready-to-eat foods, and had a manager with more than two years of experience at their current restaurant. These results suggest that to improve contamination prevention, the foodservice industry and food safety officials can consider supporting and encouraging strong food safety training and policies, particularly concerning hand hygiene, and targeting interventions to independent restaurants.

Bacterial contamination of coffee and personal exposure to inhalable dust and endotoxin in primary coffee processing factories in Ethiopia.

Endotoxins from gram-negative bacteria might be released when the coffee cherries are processed and may cause respiratory health problems among workers in the coffee industry. The relationship between bacterial contamination and occupational exposure to endotoxin levels has not been thoroughly explored previously in primary coffee processing factories in Ethiopia, or elsewhere. The aim of this study was to characterize the level of personal endotoxin exposure and its relations with bacterial contamination of coffee cherries in such factories in Ethiopia. A cross-sectional study was conducted from March 2020 - February 2021 in 9 primary coffee processing factories in 3 regions in Ethiopia. A total of 180 personal air samples were collected to analyze workers' exposure to inhalable dust and endotoxin. Correlation tests were performed to assess the relationship between total bacteria and endotoxin levels and between inhalable dust and endotoxin levels. The geometric mean (GM) of personal inhalable dust exposure among machine room workers and hand pickers were 9.58mg/m3 and 2.56mg/m3, respectively. The overall GM of endotoxin exposure among machine room workers and hand pickers were 10,198 EU/m3 and 780 EU/m3, respectively. Gram-negative bacteria were found in all 54 coffee samples. The correlation between inhalable dust and endotoxin exposure was significant (r=0.80; P <0.01). About 92% of the samples from hand pickers and all samples from machine room workers exceeded the occupational exposure limit of 90 EU/m3 recommended by the Dutch Expert Committee on Occupational Standards. Prevention and control of bacterial contamination of the coffee in primary coffee processing are suggested to reduce endotoxin exposure that might cause respiratory health problems among coffee workers.

In Situ Measurements of Dynamic Bacteria Transport and Attachment in Heterogeneous Sand-Packed Columns.

Prevention, mitigation, and regulation of bacterial contaminants in groundwater require a fundamental understanding of the mechanisms of transport and attachment in complex geological materials. Discrepancies in bacterial transport behaviors observed between field studies and laboratory experiments indicate an incomplete understanding of dynamic bacterial transport and immobilization processes in realistic heterogeneous geologic systems. Here, we develop a new experimental approach for in situ quantification of dynamic bacterial transport and attachment distribution in geologic media that relies on radiolabelingEscherichia coliwith positron-emitting radioisotopes and quantifying transport with three-dimensional (3D) positron emission tomography (PET) imaging. Our results indicate that the highest bacterial attachment occurred at the interfaces between sand layers oriented orthogonal to the direction of flow. The predicted bacterial attachment from a 3D numerical model matched the experimental PET results, highlighting that the experimentally observed bacterial transport behavior can be accurately captured with a distribution of a first-order irreversible attachment model. This is the first demonstration of the direct measurement of attachment coefficient distributions from bacterial transport experiments in geologic media and provides a transformational approach to better understand bacterial transport mechanisms, improve model parametrization, and accurately predict how local geologic conditions can influence bacterial fate and transport in groundwater.

Land resource management system in the sustainable development context: scientific and practical approaches

One of the main domestic and foreign policy principles of Ukraine is the preservation of the environment and its components, which is vital for the human existence, his current and future generations. It was found that the amount of land resources available at our disposal is limited, therefore it requires sustainable management. This calls for recognition of raising awareness importance of the rate at which humans are depleting and destroying land resources. This formed a new paradigm about the role and importance of land management and land use. The purpose of the study is to identify the factors that have the greatest impact on the spread of soil degradation and pollution, and to identify priority environmental measures in the land management system, specifically offers for land conservation, reduced land areas with the use of pesticides and agrochemicals, which would improve the state of agro and ecosystems, would create conditions for the restoration of biodiversity in the agro sphere, would contribute to the prevention of soil degradation and contamination by chemical substances. Implementation of the provided measures is aimed at improving the quality of the natural environment and human living conditions. The indicators dependence of agricultural land use and production intensification factors was revealed through economic and mathematical modeling.

Advancing herbal medicine: enhancing product quality and safety through robust quality control practices.

This manuscript provides an in-depth review of the significance of quality control in herbal medication products, focusing on its role in maintaining efficiency and safety. With a historical foundation in traditional medicine systems, herbal remedies have gained widespread popularity as natural alternatives to conventional treatments. However, the increasing demand for these products necessitates stringent quality control measures to ensure consistency and safety. This comprehensive review explores the importance of quality control methods in monitoring various aspects of herbal product development, manufacturing, and distribution. Emphasizing the need for standardized processes, the manuscript delves into the detection and prevention of contaminants, the authentication of herbal ingredients, and the adherence to regulatory standards. Additionally, it highlights the integration of traditional knowledge and modern scientific approaches in achieving optimal quality control outcomes. By emphasizing the role of quality control in herbal medicine, this manuscript contributes to promoting consumer trust, safeguarding public health, and fostering the responsible use of herbal medication products.

Describing food safety perceptions among growers and vendors in Cambodian informal vegetable markets

Improving food safety often requires individuals or groups to adopt new food safety behaviors. Understanding individuals’ perceptions of food safety is an important step in creating programs that enable the adoption of such behaviors. To inform the design of food safety programs in Cambodia, this study measured perceptions of vegetable safety among vegetable growers (n = 69; Battambang, Siem Reap) and vendors (n = 31; Phnom Penh) involved in Cambodian informal vegetable markets using a quantitative questionnaire. The majority of respondents (≥ 62.7%, lower bounds of 95% confidence intervals at least 46.2%) across all groups (growers and vendors) were at least “moderately concerned” (scale: “extremely concerned,” “moderately concerned,” “slightly concerned,” “not concerned at all”) about the safety of vegetables sold in Cambodia. However, the mean estimated probability of respondents reporting that chemical contamination was of greater concern than microbial contamination was 84.9% [76.0, 90.9]%. Most respondents reported familiarity with the health effects of consuming chemically (71.4% [61.5, 79.6]%) or microbially (57.3% [47.2, 66.9]%) contaminated vegetables. However, less than half (between 7.3% and 48.4%) of all respondents provided a commonly recognized example of such health effects. Across all groups, respondents most frequently perceived contamination of vegetables as occurring primarily “at the farm” (≥ 76.7%, lower bounds of 95% confidence intervals at least 61.5%, and ≥ 39.3%, lower bounds of 95% confidence intervals at least 21.2%, respectively). Additionally, most respondents (≥ 51.6%, lower bounds of 95% confidence intervals at least 34.0%) perceived “vegetable farmers” as primarily responsible for preventing chemical contamination. Perceptions of responsibility for preventing microbial contamination varied across groups (p = 0.02). Of the vendors in Phnom Penh, growers in Battambang, and growers in Siem Reap involved in this research, 22.6%, 39.0%, and 53.6%, respectively, described at least one commonly accepted contamination prevention practice. These results suggest that food safety programs for each of the described groups should include efforts to increase participants’ understanding of the health impacts of consuming contaminated vegetables. However, specific emphasis should be placed on increasing awareness on the health impacts of consuming vegetables contaminated with microbial pathogens as respondents were generally less aware and concerned with microbial vs. chemical contamination of vegetables. Additionally, programs targeting vegetable growers could leverage growers’ sense of personal responsibility for both contamination and contamination prevention, while programs for vegetable vendors may need to emphasize the importance of vendors in ensuring vegetable safety.

Case Study of Decreasing of Quality of Processed Waste at Sewage Treatment Plant to Contain Waste Disposal on Ship Mv. Ck Angie

Prevention of contamination by sewage on ships can be overcome by using an auxiliary sewage treatment plant, a sewage treatment plant is a liquid waste treatment installation which is generally intended for domestic waste in the form of feces and laundry residue containing detergents which are harmful to the environment by utilizing aerobic bacteria as waste decomposers and UV sterilizers as a neutralizer for waste parameters. However, in reality when the author and engineer 3 conducted regular tests on the processed water content of the sewage treatment plant from May 4 2021 to May 25 2021, the results of the waste parameters were not in accordance with the manual book. So, according to the test results above, the authors take 3 causes for the decline in the quality of processed water which is the background for writing this thesis, namely the operation of the aeration blower is ineffective, the UV sterilizer does not function properly and the accumulation of sludge or excessive solid residue in the separation tank section. The research method used is descriptive. The approach method used is a qualitative approach method with data collection techniques carried out by means of observation and documentation based on data analysis techniques carried out using root cause analysis (RCA) techniques carried out on the MV ship. CK ANGIE from 11 December 2020 to 24 January 2022. the operation of the aeration blower is ineffective, If the uv sterilizer does not function properly, the cause of the problem is the dirty blower air filter and dirty blower air inlet pipe and the uv sterilizer section is caused by the life of the uv lamp which has exceeded running hours and the uv jacket is dirty. And for engine cadets to pay attention to the exhaust air pressure from the aeration blower so that when the exhaust air pressure from the aeration blower starts to decrease, they can immediately report it to the engineer in charge. suggestions for maintaining the performance of the UV Sterilizer are to pay more attention to the usage period or running hours of the UV Lamp so that the effectiveness of the UV Lamp continues to function properly. And for the jacket section of the UV sterilizer to be cleaned regularly by implementing a regular planned maintenance system (PMS)..

Laboratory observations of solute transport in groundwater basins

This paper introduces a method of groundwater pollution source identification obtained from laboratory by a physical instrument of Flow System Sand-Box Model. A Unit basin of a simple flow system and a Tóthian basin of a hierarchically nested flow structure are introduced as case studies. We add step-input solutes at recharge zones, separately or simultaneously, to obtain the breakthrough curves (BTCs) at each discharge zone. For the Unit basin, its BTC shows a gradual upward trend with a decreasing slope but with two more pronounced steps, which differs a lot from previous results of analytical and numerical solutions. These steps are caused by the settings of the current physical instrument as no solutes are input at the upper two discharge ports. For the Tóthian basin, internal steps may exist due to the late-time arrival of intermediate and regional groundwater flow systems. Although the Unit basin and Tóthian basin can both have internal steps in the BTCs, they are due to different reasons. By jointly solving solute mass balance equations with water mass balance equations, the circulation rate for each flow system is calculated, which quantitatively explains the phenomena encountered in the experiment and highlights the important contributions of intermediate and regional flow systems to the entire groundwater circulation. We indirectly obtain the pulse-input BTCs by deriving the step-input BTCs respective to time, which is also the residence time distribution (RTD) of the groundwater basin, that the groundwater pollution sources can be identified. The pulse-input BTC is characterized by peaks and sloping tails. The peaks correspond to the intermediate and regional groundwater flow systems. The sloping tails indicate the rate at which solutes are flushed out or contaminants fade away. By inputting tap water into the groundwater basin to purify the contaminations, we conduct self-purification experiments. The shapes of the solute-input curves and the self-purification curves are systematically symmetrical. As the self-purification experiment has less external interference, it is possible to use the self-purification curves to characterize and identify the groundwater flow system. This study proposes a physical method for identifying sources of groundwater contamination, and achieves a comprehensive understanding of the law of solute transport in groundwater basins, which could guide the prevention of non-point contamination at the basin scale.

Prevention of contamination after endotracheal intubation using a dedicated sleeve.

Contamination of work surfaces by used laryngoscopes after endotracheal intubation is a serious infection control concern but no strategies are available to address it. We assessed if contamination of the surfaces after endotracheal intubation would be reduced when providers used a dedicated, self-erected, disposable plastic sleeve (BladePouch) to store the used laryngoscope as compared to using single gloves or double gloves and sheathing the laryngoscope with the outer gloves. Twenty participants were recruited including attending physicians, trainees and allied health care professionals. They performed endotracheal intubation on a mannequin with oral cavity coated with a dye and stored the used laryngoscope blade using single gloves, double gloves or BladePouch. Each participant used both direct and video laryngoscopes. Following intubation, dye contamination of gloves, gown and work surface was evaluated. There was no difference in the contamination of gloves or gowns between the single gloves, double gloves or BladePouch groups. However, work surface contamination was significantly reduced when using BladePouch compared to single or double gloves (13% vs. 100% vs. 80% respectively, P<0.001). The odds of work surface contamination were significantly lower with BladePouch vs. single or double gloves, even when adjusted for intubation device, role and experience of participants with an adjusted odds ratio of 0.0054 (95% confidence interval: 0.0009-0.0314), P<0.001. In conjunction with standard precautions, the use of a dedicated plastic sleeve to store contaminated laryngoscope blade after endotracheal intubation may reduce the work surface contamination, independent of intubation device, role and experience of providers.