Safety Criteria Research Articles

A Structural Design Approach Tailored for the Rapid Preliminary Design of Microreactor Components

High-temperature microreactors can play a role in developing reliable, portable energy sources for off-grid remote locations, microgrid concepts, and industrial process heat. Portability and passive safety criteria tend to skew microreactor structural component designs toward complex geometries, high thermal stresses, and design bases with large numbers of startup/shutdown cycles. Current design rules, as typified by Section III of the American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code, are less than optimal for these conditions, particularly for preliminary component designs where developers need to rapidly consider a large number of potential component configurations. This paper presents a design method targeted toward rapid, efficient evaluation of preliminary component designs using modern finite element analysis. The new method retains key connections with the ASME Code rules and design data while streamlining the design approach. This paper presents the design method, several verification examples illustrating the similarities and differences between the new method and the current ASME rules, and the application of the new approach to the evaluation of a test article mimicking key features of a heat pipe–cooled microreactor.

Spatial Mapping of Jamaica’s High-Resolution Wind Atlas: An Environmental-Sociotechnical Account

To utilize wind energy, how it works, its value, and where the best locations are for extrapolation must be understood. A high-resolution wind atlas of Jamaica aids the understanding of the sociophysical phenomena leading to a better understanding of wind energy on the island. This study incorporates a mesoscale method with eight years of relevant data in ArcGIS 10.8.1 to derive then indicate sites for potential onshore wind power plants (WPP). It uses secondary and real-time data from domestic and international sources to evaluate economic, environmental, and sociotechnical criteria. The results indicate a high possibility for future wind power (WP) generation expansion since 2867.15 km2, 26% of the land is available. With the installation of Vestas V80 turbines, 62,818.71 GWh/year can be generated. Conversely, Vestas V112 turbine installation can produce 56,321.74 GWh/year of electrical energy. The average speed goes up to 12.5 miles per hour, while the power density of the 10% windiest areas is between 156.60 and 768.37 W/m2 at 50 m above ground, with several parishes having appropriate locations for WPPs. Thus, 29-point sites are identified in the study. However, St. Elizabeth and Manchester are most favorable, with mean wind speeds of 8.26 m/s and 10.08 m/s, respectively, in the excellently suitable zones. The research offers several advantages, which encompass the quantification of wind potential with and without prohibition, assessment of wind suitability on the island of Jamaica, reduction in environmental damage, and available data amelioration to aid better energy policy decisions, which will ensure a faster and easier transition from fossil fuel (FF) to renewable energy (RE) to meet Jamaica’s 2030 50% RE generation target. Specifically, the atlases will assist policymakers and WP developers in making informed decisions by reducing costs, time, and ambiguities to enhance the development of renewable energy use for electrical energy in Jamaica. The Geographical Information System (GIS), which is one of the most popular energy assessment tools, was utilized to derive suitable land zones of 24.41 to 26% for onshore wind farm development in Jamaica. It incorporates environmental, economic, social, safety, and technical criteria with underlining categorical variables as indicators to derive the quantitative values appropriate for Jamaica’s landscape and comparable to international studies with similar objectives. It found that unrestricted areas can theoretically generate up to 62,818 GWh per year of electrical energy.

Mechanical recyclability of biodegradable polymers used for food packaging: case study of polyhydroxybutyrate-co-valerate (PHBV) plastic

For the purpose of mechanical recycling for food contact applications, decontamination of polyhydroxybutyrate-co-valerate (PHBV) plastic was performed under different temperatures and time conditions. As expected, increasing the decontamination temperature and duration increased the decontamination efficiency, but also the degradation of the polymer. The combination 160 °C/6 h was selected as the optimal conditions that maximize contaminants removal while minimizing polymer degradation. Then the safety of the recycled PHBV under these conditions was assessed, in accordance with EFSA regulation based on bottle-to-bottle PET recycling. Decontamination of low molecular weight molecules such as toluene, chlorobenzene, and methyl salicylate was nearly complete with residual concentrations below the modeled concentrations allowed in the polymer when the adult scenario is considered. However, the higher molecular weight and lower volatility molecules exhibited acceptable decontamination efficiencies, but their residual concentrations in the polymer exceeded the maximum concentrations of no concern. The presence of these molecules allows the use of nearly 21% recycled PHBV in the new materials to meet safety criteria. It is important to keep in mind that this work, never done before, is a preliminary work on mechanical recycling of PHBV, mainly based on extrapolation of PET conditions and regulations. Much more research needs to be done to improve the decontamination process, the barrier properties of PHBV or to think about a short recycling line for PHBV.

Hydrodynamic analysis of floating tunnel with submerged rubble mound breakwater

The wave interaction with a Submerged Floating Tunnel (SFT) of two different shapes (rectangular and circular) in the presence of a submerged rubble mound breakwater (SRMB) is analyzed using Multi-Domain Boundary Element Method (MDBEM). Furthermore, three typical SFT cross-sections (rectangular, trapezoidal, and circular) of equal area and structural height in the presence of SRMB under similar operating conditions are investigated as comparative study to analyse the influence of SFT shape on hydrodynamic performance. The performance of the tunnel configurations is analyzed as a (a) measurement in terms of hydrodynamic efficiency and (b) criterion for tunnel structure safety. In both shallow and intermediate water depth regions, the critical wave number and the critical angle of incidence followed by resonant wave reflection are identified, and suitable structural parameters of SRMB such as structural porosity in the armour layer, relative crest width, relative gap width between the SFT and the SRMB, structural width and position (relative draft of tunnel structure measured from the free water surface) of SFT are investigated. The present parametric investigation of SFT with SRMB reveals an improved wave transformation properties for a specific range of water depth. The coupling of SRMB has resulted not only in a reduction of wave-induced force acting on SFTs, but also in improved performance in wave transformation characteristics as a coastal protection structure, which is substantially determined by SRMB structural properties. Due to the presence of SRMB, the SFT's safety is improved, which may also add stability to the SFT. A comparative study of different distinct cross-sections of SFTs indicates that, due to its shape, the circular SFT has a reduced reflection capability and lower wave-induced force with nearly the same wave transmission as the rectangular and trapezoidal SFT. The study performed on the coupled SFT and rubble mound breakwater may be useful in determining the suitability of breakwaters not only for maintaining shore dynamics but also for protecting important floating structures for underwater transit.

A Multi-Indicator Evaluation Method for Spatial Distribution of Urban Emergency Shelters

Evaluation of the spatial distribution of urban emergency shelters can effectively identify defects in the current distribution of urban emergency shelters and weaknesses in the overall evacuation service capacity of the city and provide reference for improving the level of urban emergency shelters and evacuation and disaster relief capacity. At present, evaluation of the spatial distribution of urban emergency shelters is mainly carried out on three aspects: effectiveness, accessibility, and safety. However, there are problems, such as individual evaluation scales and incomplete indicator systems, unreasonable allocation of indicator weights, and ignoring the influence of fuzzy incompatibility between different indicator attributes on the evaluation results. In this paper, we start from two scales, the individual emergency shelter and the regional groups of emergency shelters. Based on the five criteria of effectiveness, accessibility, safety, suitability, and fairness, the evaluation indicator system of the spatial distribution of urban emergency shelters was constructed. It was combined with AHP, CRITIC, the optimal weight coefficient solution method based on the maximum deviation sum of squares theory, and fuzzy optimization theory to construct a multi-indicator evaluation model. Further, the spatial distribution condition of the existing emergency shelter in Shanghai was evaluated. The results show that: among the existing ninety-one emergency shelters in Shanghai, there are nine places with unreasonable spatial distribution; nineteen places are comparatively unreasonable. From the scale of regional groups, there is one district (Pudong New District) with unreasonable spatial distribution: its relative superiority value is far lower than other districts, and there are three districts that are comparatively unreasonable. Further, the evaluation scores of the spatial distribution reasonableness of emergency shelters in each region of Shanghai show a high–low–middle distribution from the downtown area of Shanghai outward. The evaluation indicator system and evaluation method used in this paper can effectively reflect the deficiencies in the spatial distribution of urban emergency shelters, thus providing a reference for the relevant departments to improve and plan emergency shelters.

Implantable dual band semi‐circular slotted patch with DGS antenna for biotelemetry applications

AbstractIn this paper, an implantable antenna with a semi‐circular slotted patch and a Z‐shaped slotted defective ground structure antenna for biotelemetry applications have been proposed. The antenna resonates at WMTS and ISM bands of 1.42 and 2.42 GHz, respectively. The antenna is compact in size with dimensions of 8 × 9 × 0.635 mm3. To validate the semi‐circular dual band antenna structure, the optimized design is fabricated on Rogers RT/duroid 6010 high dielectric substrate material. The same substrate material is adopted as the superstrate. The experiment was carried out in skin mimicking gel for both WMTS and ISM frequency bands. The designed semi‐circular slotted antenna has peak gain values of −20 dBi, at 2.42 GHz. The observed front‐to‐back ratio at the ISM band is 15.8 dB. The maximum specific absorption rate computed is within safe limits and meets IEEE safety criteria.

The Controlled Semi-Solid Fermentation of Seaweeds as a Strategy for Their Stabilization and New Food Applications.

For centuries, macroalgae, or seaweeds, have been a significant part of East Asian diets. In Europe, seaweeds are not considered traditional foods, even though they are increasingly popular in Western diets in human food applications. In this study, a biological processing method based on semi-solid fermentation was optimized for the treatment of the seaweed Gracilaria gracilis. For the first time, selected lactic acid bacteria and non-conventional coagulase-negative staphylococci were used as starter preparations for driving a bio-processing and bio-stabilization of raw macroalga material to obtain new seaweed-based food prototypes for human consumption. Definite food safety and process hygiene criteria were identified and successfully applied. The obtained fermented products did not show any presence of pathogenic or spoilage microorganisms, thereby indicating safety and good shelf life. Lactobacillus acidophilus-treated seaweeds revealed higher α-amylase, protease, lipase, endo-cellulase, and endo-xylanase activity than in the untreated sample. This fermented sample showed a balanced n-6/n-3 fatty acid ratio. SBM-11 (Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus) and PROMIX 1 (Staphylococcus xylosus) treated samples showed fatty acid compositions that were considered of good nutritional quality and contained relevant amounts of isoprenoids (vitamin E and A). All the starters improved the nutritional value of the seaweeds by significantly reducing the insoluble indigestible fractions. Preliminary data were obtained on the cytocompatibility of G. gracilis fermented products by in vitro tests. This approach served as a valid strategy for the easy bio-stabilization of this valuable but perishable food resource and could boost its employment for newly designed seaweed-based food products.

Experimental Validation of a Test Apparatus for the Evaluation of Hydrogen Permeation in Silane-Modified Sealants on Fuel-Cell-Powered Vehicles

Silane-modified sealants are widely used for the construction of railway vehicles and have several advantages in the production of elastic structural joints and seals featuring high bond thickness. The use of hydrogen fuel cells to power newly developed rolling stock places further safety constraints on the design of the sealing elements of those technical compartments that contain the storage tanks of the propulsion system. Given the lack of solutions based on the use of silane-modified sealants validated for operating environments in which leaks of gaseous hydrogen may occur, an experimental test was carried out to characterize the permeability of some adhesive products according to the requirements of the BS ISO 15105-2:2003 standard, and a specific test bench was developed for this. Two different sealants were subjected to the hydrogen permeability test. The processing of the results provided by the apparatus designed specifically for the execution of the test made it possible to determine a permeability rate dependent on the thickness of the adhesive in the order of ng/(min × cm2). The results of the test were subsequently contextualized within the technical application to rolling stock, with the ultimate aim of verifying that the permeability rate determined experimentally is compatible with the design safety criteria. The developed test bench allowed the correct execution of the permeability test. In general, the two sealants showed hydrogen permeability values compatible with the application. In particular, the hydrogen permeation rate (Rp) was lower than 0.25 ng/min for both sealants.

In Vitro Evaluation of Weizmannia coagulans Strain LMG S-31876 Isolated from Fermented Rice for Potential Probiotic Properties, Safety Assessment and Technological Properties.

Bacillus coagulans, which has been taxonomically reclassified as Weizmannia coagulans, has been the focus of research due to its wide distribution in fermented foods, probiotic properties, and tolerance to extreme environments. The purpose of this study was to characterise putative probiotic bacteria in a fermented rice sample, followed by an in vitro screening of presumptive probiotic properties and a safety assessment to ensure their safety for human consumption. The predominant isolate was Gram-positive, rod-shaped, catalase-positive, spore-forming, motile, and facultatively anaerobic. The biochemical test and 16S rDNA sequencing identify the isolate as Weizmannia coagulans strain LMG S-31876. The strain showed significant viability in acidic gastric juice, pancreatin, and bile. The strain showed tolerance to 5% NaCl, and a low-to-moderate percentage of hydrophobicity and auto-aggregation was recorded. It met all safety criteria, including haemolytic activity, DNase activity, antibiotic sensitivity, and growth inhibition of other bacteria. Evaluation of its technological properties showed positive results for amylolytic and lipolytic activities; however, negative results were obtained for proteolytic activity. It could be concluded from the gathered data that W. coagulans strain LMG S-31876 isolated from fermented rice, might serve as a potential functional probiotic food. However, extended follow-up durations and larger-scale trials by assessing the therapeutic effects in managing various clinical gastrointestinal conditions are required to warranty such effects.

Integrating Pharmacological and Computational Approaches for the Phytochemical Analysis of Syzygium cumini and Its Anti-Diabetic Potential.

Diabetes mellitus (DM) is a metabolic disease caused by improper insulin secretion leading to hyperglycemia. Syzygium cumini has excellent therapeutic properties due to its high levels of phytochemicals. The current research aimed to evaluate the anti-diabetic potential of S. cumini plant’s seeds and the top two phytochemicals (kaempferol and gallic acid) were selected for further analysis. These phytochemicals were selected via computational tools and evaluated for α-Glucosidase inhibitory activity via enzymatic assay. Gallic acid (IC50 0.37 µM) and kaempferol (IC50 0.87 µM) have shown a stronger α-glucosidase inhibitory capacity than acarbose (5.26 µM). In addition, these phytochemicals demonstrated the highest binding energy, hydrogen bonding, protein–ligand interaction and the best MD simulation results at 100 ns compared to acarbose. Furthermore, the ADMET properties of gallic acid and kaempferol also fulfilled the safety criteria. Thus, it was concluded that S. cumini could potentially be used to treat DM. The potential bioactive molecules identified in this study (kaempferol and gallic acid) may be used as lead drugs against diabetes.

Chemical air pollution in dwelling as a health risk factor

Up-to-date techniques applied in physical-chemical studies made it possible to identify and quantify chemical pollutants in the air inside contemporary dwelling in a large megacity and then create a database on them. This database has a list of more than 600 chemicals from 18 groups of volatile hydrocarbons and covers hygienic standards for their contents, their hazard category, and ranges of detected concentrations. Major sources of air pollution with these chemicals in dwelling were also identified. From the hygienic point of view, a significant fact is that there are no hygienic standards for more than 60 % of chemicals detected in air in dwelling. Formaldehyde, phenol, and styrene are priority chemicals for quality monitoring and risk-based control of hazards posed by chemical air pollution both in newly built houses that are at the approval stage and already exploited ones. Formaldehyde, benzene, phenol, styrene, acetophenone, ethylbenzene, hexanal, nonanal, butyl acetate, ethyl acetate, isopropanol, and trimethylbenzene are the most hygienically significant volatile organic compounds for quality control and health risk assessment considering frequency of their occurrence, concentration levels, concentrations exceeding MPC, group affiliation, hazard category, and ability to transform. When controlling natural chemicals that occur in air in dwelling due to some internal pollution sources, we should bear in mind that transformation may result in a new structure of pollution and new occurring chemicals can be more toxic and hazardous than original ones. To minimize risks associated with exposure to chemical pollution and to assess chemical safety of air in dwelling, we recommend wider use of up-to-date physical and chemical methods for qualitative and quantitative analysis thereby securing identification of a wide range of pollutants including potentially hazardous ones. Since certain chemicals have been detected for which no safety criteria have been developed so far, it is especially vital to perform research in the sphere of hygienic standardization and to develop methodical documents aimed at providing adequate hygienic assessment of quality and chemical safety of internal environment in dwelling.

Химическое загрязнение воздушной среды жилых помещений как фактор риска здоровью населения

Up-to-date techniques applied in physical-chemical studies made it possible to identify and quantify chemical pollutants in the air inside contemporary dwelling in a large megacity and then create a database on them. This database has a list of more than 600 chemicals from 18 groups of volatile hydrocarbons and covers hygienic standards for their contents, their hazard category, and ranges of detected concentrations. Major sources of air pollution with these chemicals in dwelling were also identified. From the hygienic point of view, a significant fact is that there are no hygienic standards for more than 60 % of chemicals detected in air in dwelling. Formaldehyde, phenol, and styrene are priority chemicals for quality monitoring and risk-based control of hazards posed by chemical air pollution both in newly built houses that are at the approval stage and already exploited ones. Formaldehyde, benzene, phenol, styrene, acetophenone, ethylbenzene, hexanal, nonanal, butyl acetate, ethyl acetate, isopropanol, and trimethylbenzene are the most hygienically significant volatile organic compounds for quality control and health risk assessment considering frequency of their occurrence, concentration levels, concentrations exceeding MPC, group affiliation, hazard category, and ability to transform. When controlling natural chemicals that occur in air in dwelling due to some internal pollution sources, we should bear in mind that transformation may result in a new structure of pollution and new occurring chemicals can be more toxic and hazardous than original ones. To minimize risks associated with exposure to chemical pollution and to assess chemical safety of air in dwelling, we recommend wider use of up-to-date physical and chemical methods for qualitative and quantitative analysis thereby securing identification of a wide range of pollutants including potentially hazardous ones. Since certain chemicals have been detected for which no safety criteria have been developed so far, it is especially vital to perform research in the sphere of hygienic standardization and to develop methodical documents aimed at providing adequate hygienic assessment of quality and chemical safety of internal environment in dwelling.

Micro-structural and mechanical properties of PVA fiber reinforced engineered cementitious composite incorporating natural and artificial pozzolanic materials under different temperatures

• The pozzolans' contents significantly affect the tensile strain capacity of the ECC. • Using fly ash, GGBS and zeolite can improve tensile behavior of the ECC. • The GGBS based ECC has better tensile stress–strain behavior. • At the temperatures above 50 °C, the mechanical properties of the ECC decrease. • ANN and MLR can predict the mechanical properties of the ECC with high accuracy. Engineered cementitious composites (ECC), which have high toughness and tensile ductility, as well as multiple fine cracking, satisfy the high safety and durability criteria in the development of sustainable infrastructures. The effect of different temperatures on the mechanical characteristics of polyvinyl alcohol (PVA) reinforced ECC (PVA-ECC) was examined in this work. A study was conducted to compare the modulus of elasticity, tensile strength, and compressive strength of samples containing various dosages of three available pozzolans: zeolites (ZE), fly ash (FA), and ground granulated blast furnace slag (GGBS), as well as silica fume (SF). Scanning electron microscopy was used to examine the microstructure of PVA-ECC samples subjected to various high temperatures (SEM). For 1 h, all specimens were exposed to temperatures of 150, 100, 50, and 20 °C. The experimental findings revealed that when the temperature rises to 50°, all three mechanical parameters, modulus of elasticity, tensile strength, and compressive strength, increase, then drop. The study of the microstructure of PVA-ECC reveals a basic explanation for the loss of macro mechanical characteristics. Finally, using ANOVA analysis, the relationship between independent parameters such as the age of the sample (AS), temperature (T), and water to pozzolan materials (W/P), and dependent parameters (i.e., compressive strength, tensile strength, and modulus of elasticity) was evaluated, and the multivariate linear regression (MLR) and the artificial neural network (ANN) were shown to be useful for modeling.

Survey on some food safety parameters of fresh ingredients in collective kitchens of factories and enterprises in Quang Ngai province in 2021

The study was carried out on raw food materials including pork, fish of all kinds and leafy vegetables at collective kitchens, industrial catering establishments at factories and enterprises. in Quang Ngai province from January to November 2021. The study aims to: determine the percentage of fresh ingredients at the collective kitchens of factories and enterprises in the area of Quang Ngai province meeting food safety criteria and study some related factors between fresh ingredients meeting food safety criteria and the origin of fresh raw materials in the study area. The results by sampling method of cross-sectional study showed that: 100% of pork met with the lean substances Salbutamol, Clenbuterol, Cimaterol by quantitative method; 13.9% fish met safety criteria for urea by quantitative method; 53.4% ​​of leafy vegetables met safety criteria for pesticides by qualitative method.

Evaluasi Kinerja Jalur Ganda Kereta Api Solobalapan - Yogyakarta

Solobalapan-Yogyakarta railway track serve up to 100 trains each day that get near to maximum lane capacity on one section of that line. Evaluation consisted of reliability, availability, maintainability and safety criteria. Ministry of Transportation issued Rencana Induk Perkeretaapian Nasional (RIPNas) 2030, so existing track’s conditions need to be estimated in 2030. On the evaluation, reliability rated by accuracy of travel duration, arrival and departure time. On availability rated by lane capacity using Scott method, and conformity of its lane carrying capacity. On maintainability and safety rated by Track Quality Index (TQI). Then, predicted number of trains pass and planned scenario analysis for 2030. Based on reliability criteria, 97% included on tolerance travel duration, but delays on arrivals and departures more than 40%. Based on availability criteria, lane capacity sufficient up to 515 trains per day, and lane carrying capacity reaches 18,171,648 tons per year. Maintenance and safety criteria based on TQI on the upstream lane of 75% is on very good condition and 61% on downstream lane is in good condition. Based on RIPNas in 2030 there will be 289 trains pass everyday, so the existing railway track is not capable to serve properly and the scenarios are increase the maximum speed to 120 km/hour and add eight block.

Assessment of Quality and Safety Criteria of Raw Milk Samples from Different Dairy Farms

Ten dairy farms supplying raw milk to the dairy industry were investigated to determine compliance with the safety criteria (plate count at 30 °C and somatic cell count) of Regulation (EC) 853/2004. The relationship of such criteria with lipid and protein percentages was also evaluated. The results demonstrated a great variability due to the different management systems of each dairy farm, with regard to the milking hygiene, the health status of the animals, and the prevention measures against mastitis. Moreover, in some dairy farms, the somatic cell counts were positively correlated with the quality components of raw milk as well as the plate count at 30 °C.

A systematic review of the feasibility and safety of day case nasal and/or palatopharyngeal surgery in patients with obstructive sleep apnoea.

Recent guidelines suggest obstructive sleep apnoea (OSA) is not an absolute contraindication for same day discharge following surgery. The aim of this systematic review was to examine the feasibility and safety of day case nasal and/or palatopharyngeal surgery in patients with OSA. We performed a systematic search of PubMed, EMBASE and the Cochrane library. Quality assessment of included studies was performed. The protocol of this systematic review was registered with PROSPERO (CRD42021273451). A total of 1836 patients from 10 observational studies were included. There were 268 (15.4%) nasal surgeries, 738 palatopharyngeal surgeries (42.4%) and 735 (42.2%) combined nasal and palatopharyngeal surgery. The majority of patients had moderate to severe OSA. A total of 860 patients (49.8%) were successfully discharged as day cases. There were no standard criteria for daycase surgery. Post-anaesthetic respiratory events were reported in 86/1750 (4.9%) patients. Oxygen desaturation was the most common respiratory event (83.7%, n=72). There was no mortality reported. Current data suggests day surgery is feasible in carefully selected patients with OSA undergoing nasal and/or palatopharyngeal surgery. Further well-designed prospective studies with an emphasis on the systematic assessment of complications are required to establish safety and daycase criteria.

Probability of failure and factor of safety in the design of interramp angles in a large open iron ore mine

This paper shows the importance of performing probabilistic analyses in open pits, especially for mine planning, which can lead to more efficient ore extraction and meeting the acceptability criteria for safety in mine slopes. Three-dimensional stability analyses were performed to evaluate the future geometry of a large open pit for iron ore extraction in Brazil. The strength parameters of the lithologies were calibrated using ruptures in the pit walls. After determining the factors of safety (FoSs) from the calibrated parameters, probabilistic analyses were performed using the total range of values of each parameter under different field conditions to verify the reliability of the initial analysis. In this sense, it was possible to plot the probability of failure (PoF) and the FoS on the graph of slope height versus slope interramp angle (IRA) for the future pit in each lithology. IRA recommendations are made for two scenarios: (1) the best scenario: dry without ubiquitous joints and (2) the worst scenario: the water table at 10 m depth with ubiquitous joints in the most unfavourable direction. The results show that probabilistic evaluation is an important tool for establishing alert mechanisms in slopes that can be termed stable.

Evaluation on Egress Safety of Nursing Hospital Considering the Smoke Exhaust System

This study aimed to evaluate the egress safety in nursing hospitals based on the capacity of the smoke exhaust system. To this end, the available safe egress time was calculated by analyzing changes in visibility, carbon monoxide, carbon dioxide, oxygen contents, and temperature depending on the fire duration. In addition, an egress simulation was performed using the number of workers (egress guides) and egress delay time as variables, and the required safe egress time was estimated. Based on the results, the egress safety of a prototype nursing hospital was evaluated. In this study, egress safety criteria to evaluate egress safety in a typical nursing hospital were presented, which are expressed in terms of normalized egress guides, the capacity ratio of the smoke exhaust system, and egress delay time. The proposed criteria can be used to evaluate the egress safety of typical nursing hospitals and to prepare complementary measures.

Safety and Effectiveness of a Catheter With Contact Force and 6-Hole Irrigation for Ablation of Persistent Atrial Fibrillation in Routine Clinical Practice

The ThermoCool SmartTouch catheter (ablation catheter with contact force and 6-hole irrigation [CF-I6]) is approved by the US Food and Drug Administration (FDA) for paroxysmal atrial fibrillation (AF) ablation and used in routine clinical practice for persistent AF ablation, although clinical outcomes for this indication are unknown. There is a need to understand whether data from routine clinical practice can be used to conduct regulatory-grade evaluations and support label expansions. To use health system data to compare the safety and effectiveness of the CF-I6 catheter for persistent AF ablation with the ThermoCool SmartTouch SurroundFlow catheter (ablation catheter with contact force and 56-hole irrigation [CF-I56]), which is approved by the FDA for this indication. This retrospective, comparative-effectiveness cohort study included patients undergoing catheter ablation for persistent AF at Mercy Health or Mayo Clinic from January 1, 2014, to April 30, 2021, with up to a 1-year follow-up using electronic health record data. Use of the CF-I6 or CF-I56 catheter. The primary safety outcome was a composite of death, thromboembolic events, and procedural complications within 7 to 90 days. The exploratory effectiveness outcome was a composite of AF-related hospitalization events after a 90-day blanking period. Propensity score weighting was used to balance baseline covariates. Risk differences were estimated between catheter groups and averaged across the 2 health care systems, testing for noninferiority of the CF-I6 vs the CF-I56 catheter with respect to the safety outcome using 2-sided 90% CIs. Overall, 1450 patients (1034 [71.3%] male; 1397 [96.3%] White) underwent catheter ablation for persistent AF, including 949 at Mercy Health (186 CF-I6 and 763 CF-I56; mean [SD] age, 64.9 [9.2] years) and 501 at Mayo Clinic (337 CF-I6 and 164 CF-I56; mean [SD] age, 63.7 [9.5] years). A total of 798 (55.0%) had been treated with class I or III antiarrhythmic drugs before ablation. The safety outcome (CF-I6 - CF-I56) was similar at both Mercy Health (1.3%; 90% CI, -2.1% to 4.6%) and Mayo Clinic (-3.8%; 90% CI, -11.4% to 3.7%); the mean difference was noninferior, with a mean of 0.5% (90% CI, -2.6% to 3.5%; P < .001). The effectiveness was similar at 12 months between the 2 catheter groups (mean risk difference, -1.8%; 90% CI, -7.3% to 3.7%). In this cohort study, the CF-I6 catheter met the prespecified noninferiority safety criterion for persistent AF ablation compared with the CF-I56 catheter, and effectiveness was similar. This study demonstrates the ability of electronic health care system data to enable safety and effectiveness evaluations of medical devices.