A Thermal Anemometry Method for Studying the Unsteady Gas Dynamics of Pipe Flows: Development, Modernisation, and Application.

A detailed study of the gas-dynamic behaviour of both liquid and gas flows is urgently required for a variety of technical and process design applications. This article provides an overview of the application and an improvement to thermal anemometry methods and tools. The principle and advantages of a hot-wire anemometer operating according to the constant-temperature method are described. An original electronic circuit for a constant-temperature hot-wire anemometer with a filament protection unit is proposed for measuring the instantaneous velocity values of both stationary and pulsating gas flows in pipelines. The filament protection unit increases the measuring system's reliability. The designs of the hot-wire anemometer and filament sensor are described. Based on development tests, the correct functioning of the measuring system was confirmed, and the main technical specifications (the time constant and calibration curve) were determined. A measuring system for determining instantaneous gas flow velocity values with a time constant from 0.5 to 3.0 ms and a relative uncertainty of 5.1% is proposed. Based on pilot studies of stationary and pulsating gas flows in different gas-dynamic systems (a straight pipeline, a curved channel, a system with a poppet valve or a damper, and the external influence on the flow), the applications of the hot-wire anemometer and sensor are identified.

Electrocardiogram Devices for Home Use: Technological and Clinical Scoping Review.

BACKGROUND: Electrocardiograms (ECGs) are used by physicians to record, monitor, and diagnose the electrical activity of the heart. Recent technological advances have allowed ECG devices to move out of the clinic and into the home environment. There is a great variety of mobile ECG devices with the capabilities to be used in home environments. OBJECTIVE: This scoping review aimed to provide a comprehensive overview of the current landscape of mobile ECG devices, including the technology used, intended clinical use, and available clinical evidence. METHODS: We conducted a scoping review to identify studies concerning mobile ECG devices in the electronic database PubMed. Secondarily, an internet search was performed to identify other ECG devices available in the market. We summarized the devices' technical information and usability characteristics based on manufacturer data such as datasheets and user manuals. For each device, we searched for clinical evidence on the capabilities to record heart disorders by performing individual searches in PubMed and ClinicalTrials.gov, as well as the Food and Drug Administration (FDA) 510(k) Premarket Notification and De Novo databases. RESULTS: From the PubMed database and internet search, we identified 58 ECG devices with available manufacturer information. Technical characteristics such as shape, number of electrodes, and signal processing influence the capabilities of the devices to record cardiac disorders. Of the 58 devices, only 26 (45%) had clinical evidence available regarding their ability to detect heart disorders such as rhythm disorders, more specifically atrial fibrillation. CONCLUSIONS: ECG devices available in the market are mainly intended to be used for the detection of arrhythmias. No devices are intended to be used for the detection of other cardiac disorders. Technical and design characteristics influence the intended use of the devices and use environments. For mobile ECG devices to be intended to detect other cardiac disorders, challenges regarding signal processing and sensor characteristics should be solved to increase their detection capabilities. Devices recently released include the use of other sensors on ECG devices to increase their detection capabilities.

Comparación de las características epidemiológicas, clínicas y quirúrgicas de pacientes con y sin recidiva de hernias inguinales operados en el Centro Médico Naval.

BACKGROUND: Recurrent inguinal hernia is currently considered a complex hernia of the abdominal wall after it has been managed with a primary procedure, which represents a more technically challenging hernia. OBJECTIVE: To determine the difference in epidemiological, clinical and surgical characteristics of patients with recurrent inguinal hernia and patients without recurrence. METHOD: Analytical cross-sectional study, in people over 18 years of age after surgery for inguinal hernia at the Naval Medical Center during the period from July 1, 2016 to June 30, 2019, integrating two study groups. RESULTS: 106 patients were included, 29 surgeries for recurrence, predominance of men and older than 60 years. Differences was found between the group of surgery for recurrence and the group of primary surgery in surgical time in minutes, with medians of 115 (p25 75 and p75 154) and 72 (p25 58 and p75 110), respectively (p = 0.001); type of open approach, 62.1% and 88.3% (p = 0.005), and type of regional anesthesia, 48.3% and 75.3% (p = 0.008). Correlation between body mass index and size of the hernial defect was explored, obtaining r of -0.099 and p = 0.652, with a null correlation between them. CONCLUSIONS: With the findings obtained in this study, it is possible to hypothesize the behavior of the naval population which may differ from the general population and thus establish follow-up protocols to give magnitude to already known factors.

ANTECEDENTES: La hernia inguinal recidivante es considerada actualmente como una hernia compleja de la pared abdominal después de que se haya manejado con un procedimiento primario, lo que representa una hernia con un mayor desafío técnico. OBJETIVO: Determinar las diferencias en las características epidemiológicas, clínicas y quirúrgicas de pacientes con hernia inguinal recidivante y sin recidiva. MÉTODO: Estudio transversal analítico en mayores de 18 años operados por hernia inguinal en el Centro Médico Naval durante el periodo del 1 de julio de 2016 al 30 de junio de 2019, integrando dos grupos de estudio. RESULTADOS: Se incluyeron 106 pacientes, 29 cirugías por recidiva, predominio de hombres y mayores de 60 años. Se encontraron diferencias entre el grupo de cirugía por recidiva y el grupo de cirugia primaria en tiempo quirúrgico, con medianas de 115 (p25 75 y p75 154) y 72 (p25 58 y p75 110) minutos, respectivamente (p = 0.001); tipo de abordaje, abierto 62.1% y 88.3% (p = 0.005); y tipo de anestesia, regional 48.3% y 75.3% (p = 0.008). Se exploró la correlación entre el índice de masa corporal y el tamaño del defecto herniario, obteniendo r de −0.099 y p = 0.652, con una correlación nula entre ambas. CONCLUSIONES: Con los hallazgos obtenidos en este estudio es posible plantear hipótesis del comportamiento de la población naval que pueda diferir de la población general, y con esto establecer protocolos de seguimiento para dar magnitud a factores ya conocidos.

How does interactive virtual reality enhance learning outcomes via emotional experiences? A structural equation modeling approach.

Introduction: Interest in interactive virtual reality (IVR) is increasing due to its potential for embodied learning and group-led teaching. However, few studies have investigated the internal mechanism by which IVR technology features and learning experiences affect learning outcomes in terms of psychological and emotional value. Based on media technology models and the control value theory of achievement emotions (CVTAE), this study uses structural equation modeling (SEM) to investigate the correlations among the internal elements of IVR technology features, learning experiences, and learning outcomes. It also emphasizes the role played by emotional experience in this context. Methods: The sample referenced by this study consisted of 480 college students (193 males) who were simultaneously engaged in guided inquiry and learning in an IVR-based COVID-19 pandemic science museum in groups of 10. Results: The findings suggest that presence and perceived enjoyment have a key mediating effect on the relationship between virtual reality (VR) features and perceived learning outcomes in an IVR-based learning simulation. In addition, the results indicate that presence is more strongly correlated with perceived learning effects, while enjoyment is more strongly correlated with learning satisfaction. Discussion: These findings provide intellectual support and theoretical backing for VR-based instructional design and environmental development. Moreover, this study has practical value with regard to the future large-scale application of IVR to experiential teaching, group-led teaching, and the promotion of the digital transformation and intelligence upgrading in education.

Liquid hot water as sustainable biomass pretreatment technique for bioenergy production: A review.

In recent years, lignocellulosic biomass has emerged as one of the most versatile energy sources among the research community for the production of biofuels and value-added chemicals. However, biomass pretreatment plays an important role in reducing the recalcitrant properties of lignocellulose, leading to superior quality of target products in bioenergy production. Among existing pretreatment techniques, liquid hot water (LHW) pretreatment has several outstanding advantages compared to others including minimum formation of monomeric sugars, significant removal of hemicellulose, and positive environmental impacts; however, several constraints of LHW pretreatment should be clarified. This contribution aims to provide a comprehensive analysis of reaction mechanism, reactor characteristics, influencing factors, techno-economic aspects, challenges, and prospects for LHW-based biomass pretreatment. Generally, LHW pretreatment could be widely employed in bioenergy processing from biomass, but circular economy-based advanced pretreatment techniques should be further studied in the future to achieve maximum efficiency, and minimum cost and drawbacks.

A review of the characteristics of Fenton and ozonation systems in landfill leachate treatment.

The development and application of Fenton and ozonation systems in landfill leachate treatment over the last 20 years, and the current research status are reviewed in this paper, with an emphasis on the technical and economic characteristics of Fenton and ozonation systems used to treat different types of landfill leachate. To date, a total of 101 and 78 articles have been published regarding leachate treatment by Fenton and ozonation systems, respectively. These articles considered the use of two systems to treat aged leachate, biologically treated leachate and leachate comprising the concentrated solution resulting from reverse osmosis (RO). The oxidization mechanisms of the two systems used to treat landfill leachate significantly differed in terms of their optimal process parameters (e.g., initial pH value, reagent dosage, and reaction time) and removal efficiency. The Fenton and ozonation systems outperformed persulfate-based advanced oxidation technology in terms of their improved biodegradability of landfill leachate and engineering practicability. The cost of the reagents required to treat landfill leachate by Fenton and ozonation systems accounted for at least 85% of the total operating cost. In contrast to the ozonation system, the Fenton system was more cost-effective when both systems were used to treat the same type of landfill leachate. This study provides a theoretical basis for the operation of Fenton and ozonation systems and also offers technical support for landfill leachate disposal companies that opt to use these technologies.

[Clinical efficacy and technical characteristics of percutaneous endoscopic lumbar discectomy in the treatment of upper lumbar disc herniation].

OBJECTIVE: To analyze the clinical efficacy and technical characteristics of percutaneous endoscopic lumbar discecomy in the treatment of upper lumbar disc herniation. METHODS: The clinical data of 9 patients with upper lumbar disc herniation underwent percutaneous endoscopic lumbar discecomy from January 2012 to October 2019 were retrospectively analyzed. There were 6 males and 3 females, aged 26 to 79 years, including 2 patients with L1,2 disc herniation and 7 patients with L2, 3 disc herniation. Visual analogue scale (VAS) and Japanese Orthopeadic Association (JOA) score were recorded before and after surgery. The clinical efficacy was evaluated according to the modified Macnab standard. RESULTS: All 9 patients were followedup, and the follow-up time was 1 day and 3 months after surgery. The operation time was 1.5 to 2.9 h and postoperative hospital stay was 5 to 8 d. No cerebrospinal fluid leakage or spinal cord injury occurred during the operation. Preoperative and postoperative at 1 day, 3 months, the VAS scores of 9 patients were 7 to 8 scores, 1 to 3 scores, 0 to 1 case, JOA scores were 5 to 7 scores, 15 to 24 scores, 21 to 26 scores, respectively. The improvement rate of JOA was 36.4% to 78.3% on the first day and 65.2% to 87.5% three months after operation. According to modified Macnab standard to evaluate effect, 4 cases got excellent results, 4 good, 1 fair. CONCLUSION: Percutaneous endoscopic lumbar discecomy has reliable therapeutic effect for upper lumbar disc herniation in line with the indications, and it has the characteristics of small trauma and short operation time, so it is more suitable for middle aged and elderly patients with poor physique and can replace part of transforaminal lumbar interbody fusion.

Clinical efficacy and technical characteristics of percutaneous endoscopic lumbar discectomy in the treatment of upper lumbar disc herniation / 中国骨伤

OBJECTIVE@#To analyze the clinical efficacy and technical characteristics of percutaneous endoscopic lumbar discecomy in the treatment of upper lumbar disc herniation.@*METHODS@#The clinical data of 9 patients with upper lumbar disc herniation underwent percutaneous endoscopic lumbar discecomy from January 2012 to October 2019 were retrospectively analyzed. There were 6 males and 3 females, aged 26 to 79 years, including 2 patients with L disc herniation and 7 patients with L2, 3 disc herniation. Visual analogue scale (VAS) and Japanese Orthopeadic Association (JOA) score were recorded before and after surgery. The clinical efficacy was evaluated according to the modified Macnab standard.@*RESULTS@#All 9 patients were followedup, and the follow-up time was 1 day and 3 months after surgery. The operation time was 1.5 to 2.9 h and postoperative hospital stay was 5 to 8 d. No cerebrospinal fluid leakage or spinal cord injury occurred during the operation. Preoperative and postoperative at 1 day, 3 months, the VAS scores of 9 patients were 7 to 8 scores, 1 to 3 scores, 0 to 1 case, JOA scores were 5 to 7 scores, 15 to 24 scores, 21 to 26 scores, respectively. The improvement rate of JOA was 36.4% to 78.3% on the first day and 65.2% to 87.5% three months after operation. According to modified Macnab standard to evaluate effect, 4 cases got excellent results, 4 good, 1 fair.@*CONCLUSION@#Percutaneous endoscopic lumbar discecomy has reliable therapeutic effect for upper lumbar disc herniation in line with the indications, and it has the characteristics of small trauma and short operation time, so it is more suitable for middle aged and elderly patients with poor physique and can replace part of transforaminal lumbar interbody fusion.

Technical characteristics and clinical feasibility of 2 implant supported immediate loading mandibular implant complete denture by linear occlusion / 中国生化药物杂志

Objective To investigate the technical characteristics and clinical feasibility of 2 implant supported immediate loading mandibular implant complete denture by linear occlusion.Methods40 cases of edentulous patients in the fifth people's hospital of yuhang district hangzhou from January 2011 to January 2017 were selected, these patients were divided into 2 implants supported immediate loading implant supported mandibular complete overdenture group (immediate loading implant group, n=20) and conventional complete denture repair group (n=20) two groups according to the treatment methods, the planting denture satisfactions, body marginal bone resorption, complications of the two groups were statistically analyzed.ResultsThe planting retention function, masticatory function, language function, comfort scores of the immediate loading implant group were significantly higher,there was significant difference between two groups(P<0.05), the bone resorption was significantly lower,there was significant difference between two groups(P<0.05), the incidence of complications 10% (2/20) was significantly lower than the conventional complete denture repair group 40% (8/20).there was significant difference between two groups(P<0.05).ConclusionThe clinical feasibility of 2 implant supported immediate loading mandibular implant complete denture by linear occlusion is higher than conventional complete denture repair.

Technical Characteristics of Infantile Massage in the Treatment of 240 Infants with Acute Diarrhea / 世界科学技术-中医药现代化

This study was aimed to objectively evaluate the validity and safety of normalized Tuina massage thera-py on the treatment of 240 infants with acute diarrhea, thus disseminate and promote the application of infantile Tuina massage therapy. This study is a multicenter, randomized, controlled trial of 240 cases with acute infantile diarrhea. The experimental group (180 cases) was treated with Tuina massage therapy. The main acupoints are Pi-jing, Da-chang, Lan-men. And the combining acupoint is San-guan. In the control group (60 cases), the pa-tients were orally administered with Smecta. The statistical analysis was conducted with SPSS 15.0. The compre-hensive curative effect, time point effect, safety and technical stability of infantile Tuina massage were evaluated in the treatment of acute diarrhea. The results showed that the comprehensive effect of cure rate in the experi-mental group was 75.6% (136/180), and that of the control group was 21.7% (13/60). It showed that the effect in the experimental group was significantly better than the control group (P 0 . 05 ) . Furthermore , there was no side effect in both groups. It was concluded that the infantile massage technique is an effective therapy for the treatment of acute diarrhea . Meanwhile , it is a safe and stable therapy and is worth popularizing .