Impact of non-alcoholic fatty liver disease on coronavirus disease 2019: A systematic review

BACKGROUND Many studies have revealed a link between non-alcoholic fatty liver disease(NA-FLD)and coronavirus disease 2019(COVID-19),making understanding the relationship between these two conditions an absolute requirement.AIM To provide a qualitative synthesis on the currently present data evaluating COVID-19 and NAFLD.METHODS This systematic review was conducted in accordance with the guidelines pro-vided by preferred reporting items for systematic reviews and meta-analyses and the questionnaire utilized the population,intervention,comparison,and outcome framework.The search strategy was run on three separate databases,PubMed/MEDLINE,Scopus,and Cochrane Central,which were systematically searched from inception until March 2024 to select all relevant studies.In addition,ClinicalTrials.gov,Medrxiv.org,and Google Scholar were searched to identify grey literature.RESULTS After retrieval of 11 studies,a total of 39282 patients data were pooled.Mortality was found in 11.5%and 9.4%of people in NAFLD and non-NAFLD groups.In all,23.2%of NAFLD patients and 22%of non-NAFLD admissions diagnosed with COVID-19 were admitted to the intensive care unit,with days of stay varying.Ventilatory support ranged from 5%to 40.5%in the NAFLD cohort and from 3.1%to 20%in the non-NAFLD cohort.The incidence of acute liver injury showed significance.Clinical improvement on days 7 and 14 between the two classifications was significant.Hospitalization stay ranged from 9.6 days to 18.8 days and 7.3 days to 16.4 days in the aforementioned cohorts respectively,with 73.3%and 76.3%of patients being discharged.Readmission rates varied.CONCLUSION Clinical outcomes except mortality consistently showed a worsening trend in patients with NAFLD and concomitant COVID-19.Further research in conducting prospective longitudinal studies is essential for a more powerful conclusion.

Practice and analysis of recycling non-drinking water from air-condition and reverse-osmosis system into rainwater collection system

This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.

Development of underground mine monitoring and communication system integrated ZigBee and GIS

An automated underground mine monitoring and communication system based on the integration of new technologies is introduced to promote safety and health,operational management and cost-effectiveness.The proposed system integration considering Wireless Sensor Network(WSN) assisted Geographic Information System(GIS) enables to monitor and control underground mining applications from surface office.Based on the capabilities of WSNs,ZigBee network is adapted for near real-time monitoring,ventilation system control and emergency communication in underground mine.ZigBee nodes were developed to sense environmental attributes such as temperature,humidity and gases concentration;switching ON and OFF ventilation fans;and texting emergency messages.A trigger action plan for monitored attributes above normal and threshold value limits is programmed in the surface GIS management server.It is designed to turn the auxiliary fans on remotely or automatically in orange condition and sending evacuation messages for underground miners in unsafe(red) condition.Multi-users operation and 3D visualisations are other successful achievements of the proposed system for the underground monitoring and communication.

Gas drainage from different mine of drainage systems for deep coal areas： optimal placement seams with high gas emissions

The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applied successfully. However, as the mining depth increasing, parts of the gas drainage system are not suitable for mines with high gas emissions. Because larger mining depths cause higher ground stresses, it becomes extremely difficult to maintain long gob side roadways. The greater deformation suffered by the roadway is not favorable lor borehole drilling for continuous gas drainage. To solve these problems, Y-type ventilation and gas drainage systems installed from a roof roadway were designed for drainage optimization. This system was designed based on a gas-enrichment zone analysis developed from mining the 11-2 coal seam in the Zhuji Mine at Huainan, Anhui Province, China. The method of Y-type gas extraction from different mine areas was applied to the panel 1112（1） in the Zhuji Mine. The absolute gas emission rate was up to 116.3 m^3/min with an average flow of 69.1 m^3/min at an average drainage concentration of nearly 85 %. After the Y-type method was adopted, the concentration of gas in the return air was 0.15 %-0.64 %, averaging 0.39 % with a ventilation rate of 2100-2750 m^3/min. The gas management system proved to be efficient, and the effective gas control allowed safe production to continue .

Fault Diagnosis Approach of Local Ventilation System in Coal Mines Based on Multidisciplinary Technology

In order to reduce the probability of fault occurrence of local ventilation system in coal mine and prevent gas from exceeding the standard limit, an approach incorporating the reliability analysis, rough set theory, genetic algorithm (GA), and intelligent decision support system (IDSS) was used to establish and develop a fault diagnosis system of local ventilation in coal mine. Fault tree model was established and its reliability analysis was performed. The algorithms and software of key fault symptom and fault diagnosis rule acquiring were also analyzed and developed. Finally, a prototype system was developed and demonstrated by a mine instance. The research results indicate that the proposed approach in this paper can accurately and quickly find the fault reason in a local ventilation system of coal mines and can reduce difficulty of the fault diagnosis of the local ventilation system, which is significant to decrease gas exploding accidents in coal mines.

Stability of mine ventilation system based on multiple regression analysis

In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air （ Qj ） is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable （ Ri ）, i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems.

Cloud model-clustering analysis based evaluation for ventilation system of underground metal mine in alpine region

Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.

Effects of diabetic ketoacidosis in the respiratory system

Diabetes affects approximately 30 million persons in the United States. Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabetic ketoacidosis(DKA), several metabolic and electrolyte derangements can ultimately result in respiratory compromise. Most commonly, hypokalemia, hypomagnesemia and hypophosphatemia can eventually lead to respiratory muscles failure.Furthermore, tachypnea, hyperpnea and more severely, Kussmaul breathing pattern can develop. Also, hydrostatic and non-hydrostatic pulmonary edema can occur secondary to volume shifts into the extracellular space and secondary to increased permeability of the pulmonary capillaries. The presence of respiratory failure in patients with DKA is associated with higher morbidity and mortality. Being familiar with the causes of respiratory compromise in DKA, and how to treat them, may represent better outcomes for patients with DKA.

Sensitivity analysis on parameter changes in underground mine ventilation systems

A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.

Computational Fluid Dynamics Simulation of Indoor Air Quality and Thermal Stratification of an Underfloor Air Distribution System(UFAD)with Various Vent Layouts

The underfloor air distribution(UFAD)system has not been able to penetrate the residential and commercial air conditioning industry significantly until now.To date,the most notable applications are found in datacenters because of their more demanding thermal stratification and cooling requirements.In addition to highlighting the advantages of the UFAD system over the traditional overhead(OH)system,this study compares various ventilation layouts for a UFAD system.Four different UFAD ventilation layouts are compared and one OH layout.The results show that using multiple swirl-type diffusers creates a more uniform floor-to-knee temperature and less air recirculation than the rectangular grille-type diffusers.Placing the return vents on the sides of the room creates a cooler environment by isolating recirculating air to a smaller space.At the end of the study,a design guide matrix is presented to summarize how the supply and return vent layout affects air conditioning performance.

Design of push-pull system to control diesel particular matter inside a dead-end entry

Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include： long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.

Closed-loop bulk air conditioning: A renewable energy-based system for deep mines in arctic regions

With depletion of shallow deposits,the number of underground mines expected to reach more than 3 km depth during their lifetime is growing.Although surface cooling plants are mostly effective in mine airconditioning,usually secondary cooling units are needed below 2 kmdepth.This need emerges due to the elevated thermal impacts caused by auto-compression of mine air as well as heat emissions from strata and mine machinery.As a result,in cold climates,like Canada,ultra-deep mines need their secondary underground cooling plants running year-round while the intake air must be heated to protect the sensitive machinery and liners from freezing during the winter season.To cool mine air,horizontal bulk-airconditioners with direct spray cooling systems are commonly used due to their high performance.Conventionally,sprayed water in bulk-air-coolers are mechanically circulated and refrigerated in coupled refrigeration plants.This set up can be transformed to a natural cooling/heating process by resurfacing the warm underground bulk-air-cooler spray water for mine air heating on the surface and re-sinking the chilled water for cooling in the underground bulk air coolers.This could significantly cut-down the fossil-fuel consumption in burners for mine air pre-conditioning and refrigeration cost when applicable.This paper presents an anonymous real-life example to study the feasibility of the proposed idea for an ultra-deep Canadian mine.

A Review on Effects of Personalized Ventilation Systems on Air Quality and Thermal Comfort in Aircraft Cabin Mini-Environments

This study conducts an evaluation of air quality,dispersion of airborne expiratory pollutants and thermal comfort in aircraft cabin mini-environments using a critical examination of significant studies conducted over the last20 years.The research methods employed in these studies are also explained in detail.Based on the current literature,standard procedures for airplane personal ventilation and air quality investigations are defined for each study approach.Present study gaps are examined,and prospective study subjects for various research approaches are suggested.

Assessment Index Structure of Mine Ventilation System and Application

Based on the basic content of advanced technology,safety and reliability, and economic reasonability and the definition of mine ventilation system, 16 assessment indexes of ventilation system are put forward from the point of 8 aspects such as mine ventilation power, ventilation network, ventilation equipments, ventilation quality, ventilation monitoring, capacity of preventing and fighting disaster, ventilation consumption of power, and the capacity of ventila- tion system. A new assessment index system is put forward and has a good effect after being applied in coal mines.

Numerical simulation to evaluate gas diffusion of turbulent flow in mine ventilation system

Tracer gas technique is a method to analyze the airflow path, measure the airflow quantity, and detect any recirculation or leakages in underground mine. In addition, it is also possible to evaluate the axial gas diffusion of gas in turbulent bulk flow by utilizing the tracer gas data. This paper discussed about the measurement using tracer gas technique in Cibaliung Underground Mine, Indonesia and the evaluation of effective axial diffusion coefficient, E, by numerical simulation. In addition, a scheme to treat network flow in mine ventilation system was also proposed. The effective axial diffusion coefficient for each airway was evaluated based on Taylor's theoretical equation. It is found that the evaluated diffusion coefficient agrees well with Taylor's equation by considering that the wall friction factor, f, is higher than those for smooth pipe flow. It also shows that the value of effective diffusion coefficient can be inherently determined and the value is constant when matching with other measurements. Furthermore, there are possibilities to utilize the tracer gas measurement data to evaluate the airway friction factors.

Self-Power Consumption Research with the Thermal Effects and Optical Properties of the HCRI-BIPV Window System

The building integrated photovoltaics （BIPV） application is one of the main study topics in the sustainable building field. In this paper, the high color rendering index （HCRI）-BIPV window system is developed to be used in the indoor environmental control, whose module material has appeared to be effective in improving the visible transmittance and reducing the absorption. This paper describes the performance of grid-connected HCRI-BIPV window system with 0.75 kWp capacity installed in an office building for a natural ventilation solution. The experimental results indicate that accumulative power generation of the HCRI-BIPV window system is 157.60 WKh during the 7-month experiment period. For consideration of each evaluated factors, the HCRI-BIPV window system not only offers the passive energy situation for its power loading but also improves the indoor thermal environment by natural ventilation.

Research on an active and continuous monitoring system for human respiratory system

Continuous and dynamic measurements of human respiratory parameters are very important for vital diseases of respiratory system during mechanical ventilation. This paper analyzed the structure and mechanical properties of the human respiratory system, and designed an active intervening monitoring micro system for it. The mobile mechanism of the micro system is soft and earthworm-like movement actuated by pneumatic rubber actuator, the measurement and therapy unit of the system is an extensible mechanism with sensors in the front. The micro monitoring system can move in respiratory tract and measure the respiratory parameters in bronchium continuously. Experiments had been done in swine＇s respiratory tract, the results proved that the micro robot system could measure the respiratory parameters in real-time successfully and its movement was smith in swine＇s respiratory tract.

Numerical Analysis on Ventilating and Air Conditioning Scheme of Shenyang Subway Station

Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.

Digestive system involvement and clinical outcomes among COVID-19 patients:A retrospective cohort study from Qatar

BACKGROUND Coronavirus disease 2019(COVID-19)caused by the severe acute respiratory syndrome coronavirus 2 virus most commonly presents with respiratory symptoms.While gastrointestinal(GI)manifestations either at presentation or during hospitalization are also common,their impact on clinical outcomes is controversial.Some studies have described worse outcomes in COVID-19 patients with GI symptoms,while others have shown either no association or a protective effect.There is a need for consistent standards to describe GI symptoms in COVID-19 patients and to assess their effect on clinical outcomes,including mortality and disease severity.AIM To investigate the prevalence of GI symptoms in hospitalized COVID-19 patients and their correlation with disease severity and clinical outcomes.METHODS We retrospectively reviewed 601 consecutive adult COVID-19 patients requiring hospitalization between May 1-15,2020.GI symptoms were recorded at admission and during hospitalization.Demographic,clinical,laboratory,and treatment data were retrieved.Clinical outcomes included all-cause mortality,disease severity at presentation,need for intensive care unit(ICU)admission,development of acute respiratory distress syndrome,and need for mechanical ventilation.Multivariate logistic regression model was used to identify independent predictors of the adverse outcomes.RESULTS The prevalence of any GI symptom at admission was 27.1%and during hospitalization was 19.8%.The most common symptoms were nausea(98 patients),diarrhea(76 patients),vomiting(73 patients),and epigastric pain or discomfort(69 patients).There was no difference in the mortality between the two groups(6.21%vs 5.5%,P=0.7).Patients with GI symptoms were more likely to have severe disease at presentation(33.13%vs 22.5%,P<0.001)and prolonged hospital stay(15 d vs 14 d,P=0.04).There was no difference in other clinical outcomes,including ICU admission,development of acute respiratory distress syndrome,or need for mechanical ventilation.Drugs associated with the development of GI symptoms during hospitalization were ribavirin(diarrhea 26.37%P<0.001,anorexia 17.58%,P=0.02),hydroxychloroquine(vomiting 28.52%,P=0.009)and lopinavir/ritonavir(nausea 32.65%P=0.049,vomiting 31.47%P=0.004,and epigastric pain 12.65%P=0.048).In the multivariate regression analysis,age>65 years was associated with increased mortality risk[odds ratio(OR)7.53,confidence interval(CI):3.09-18.29,P<0.001],ICU admission(OR:1.79,CI:1.13-2.83,P=0.012),and need for mechanical ventilation(OR:1.89,CI:1.94-2.99,P=0.007).Hypertension was an independent risk factor for ICU admission(OR:1.82,CI:1.17-2.84,P=0.008)and need for mechanical ventilation(OR:1.66,CI:1.05-2.62,P=0.028).CONCLUSION Patients with GI symptoms are more likely to have severe disease at presentation;however,mortality and disease progression is not different between the two groups.

Simulation Analysis of Ammonia Leakage and Dispersion in a Large-Scale Refrigeration System

The use of ammonia in large-scale refrigeration systems(such as those used for a stadium)requires adequate ammonia leakage prevention mechanisms are put in place.In the present study,numerical simulations have been conducted to study the dispersion law in the ammonia machinery room of the refrigeration system for the 2022 Beijing Winter Olympics.The wind speed,and release location have been varied to investigate their effects on the dispersion profile.Different positions of the leakage points in the ammonia storage tank have been found to lead to different areas affected accordingly.In general,the dangerous region area decreases with an increase in the wind speed.However,when the wind is aligned with the leakage direction,this trend is reverted.The study may offer an effective method to predict the impact of ammonia dispersion and implement the safe operation of such large-scale systems.