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1.
BMC Public Health ; 24(1): 1657, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38907192

RESUMEN

BACKGROUND: With the conflict between the promise of ageing in health and longevity and the limited availability of health resources and social support, older adults in China inevitably experience anxieties surrounding health risks. This study aims to investigate how older adults perceive the health risks that come with getting older, explore the degree to which health risks affect older adults, and advocate for active engagement in practices for managing health risks. METHODS: Using purposive sampling, three districts of Beijing (Xicheng District, Fengtai District, and Daxing District, respectively) were selected for the research. Qualitative semi-structured and in-depth interviews were conducted with 70 community-dwelling older adults who participated in the study. Data were extracted and analyzed based on a thematic framework approach. RESULTS: Three main themes were identified: (i) the anxieties of older adults concerning health risks in ageing; (ii) the priorities of older adults for health risk management in ageing; (iii) the expectations of older adults for health risk management in ageing. The primary health concerns among older adults included disease incidence and function decline. It was found that basic health management emerged as a critical need for older adults to mitigate health risks. Moreover, it was observed that healthcare support for older adults from familial, institutional, and governmental levels exhibited varying degrees of inadequacy. CONCLUSIONS: The primary source of anxieties among older adults regarding health risks predominantly stems from a perceived sense of health deprivation. It is often compounded by persistent barriers to primary care of priorities in managing health risks among older adults. In addition, the expectations of older adults for health risk management emphasize the necessity for integrated care approaches. Therefore, further research should give priority to the prevention and management of health risks, aim to reduce anxieties, provide integrated care to meet the primary needs and expectations of older adults, and ultimately strive toward the overarching goal of promoting health and longevity.


Asunto(s)
Ansiedad , Vida Independiente , Investigación Cualitativa , Humanos , Anciano , Femenino , Masculino , Vida Independiente/psicología , Anciano de 80 o más Años , Ansiedad/psicología , Ansiedad/epidemiología , Persona de Mediana Edad , Envejecimiento/psicología , Entrevistas como Asunto , China/epidemiología , Medición de Riesgo , Prioridades en Salud
2.
Artículo en Inglés | MEDLINE | ID: mdl-39005076

RESUMEN

BACKGROUND: Person-centered primary care measures (PCPCM) facilitate high-quality and culturally appropriate primary care. Access to PCPCM remains unequal between rural and urban areas, and the available evidence on rural PCPCM is still lacking. METHODS: A cross-sectional survey was conducted with stratified sampling by regions, and four districts (Xicheng, Fengtai, Huairou, and Daxing) in Beijing were selected to test the performance of PCPCM in both urban and rural areas. Descriptive statistical methods were used to compare the urban-rural differences in the demographic characteristics of PCPCM. Correlation and regression analyses were performed to determine the associations between PCPCM in demographics and utilization of primary care. RESULTS: The PCPCM showed good reliability and validity in both urban and rural areas (P< 0.001), slightly lower in rural areas, but scores of rural PCPCM (R-PCPCM) in all items were lower than urban PCPCM (U-PCPCM). The PCPCM score for preferring CHCs (U-PCPCM=3.31) or RHCs (R-PCPCM=3.10) was the highest. Patients in urban areas were more likely to receive higher-quality primary care than in rural areas (P < 0.001). Patients who preferred hospitals (ß=2.61, p<0.001) or CHCs (ß=0.71, p=0.003) as providers was a significant positive predictor of U-PCPCM, but it was the preference for hospitals (ß=2.95, p<0.001) for R-PCPCM. CONCLUSIONS: Urban-rural differences existed in the performance of PCPCM, with rural areas typically more difficult to access better PCPCM. To promote health equity in rural areas, healthcare providers should strive to minimize urban-rural differences in the quality and utilization of primary care services as much as feasible.

3.
Neural Plast ; 2023: 9303419, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36910013

RESUMEN

Referred somatic pain triggered by hyperalgesia is common in patients with inflammatory bowel disease (IBD). It was reported that sprouting of sympathetic nerve fibers into the dorsal root ganglion (DGR) and neurogenic inflammation were related to neuropathic pain, the excitability of neurons, and afferents. The purpose of the study was to explore the potential and mechanism of electroacupuncture (EA) at Zusanli (ST36) for the intervention of colon inflammation and hyperalgesia. Sprague-Dawley (SD) was randomly divided into four groups, including control, model, EA, and sham-EA. Our results showed EA treatment significantly attenuated dextran sulfate sodium- (DSS-) induced colorectal lesions and inflammatory cytokine secretion, such as TNF-α, IL-1ß, PGE2, and IL-6. EA also inhibited mechanical and thermal pain hypersensitivities of colitis rats. Importantly, EA effectively abrogated the promotion effect of DSS on ipsilateral lumbar 6 (L6) DRG sympathetic-sensory coupling, manifested as the sprouting of tyrosine hydroxylase- (TH-) positive sympathetic fibers into sensory neurons and colocalization of and calcitonin gene-related peptide (CGRP). Furthermore, EA at Zusanli (ST36) activated neurogenic inflammation, characterized by decreased expression of substance P (SP), hyaluronic acid (HA), bradykinin (BK), and prostacyclin (PGI2) in colitis rat skin tissues corresponding to the L6 DRG. Mechanically, EA treatment reduced the activation of the TRPV1/CGRP, ERK, and TLR4 signaling pathways in L6 DRG of colitis rats. Taken together, we presumed that EA treatment improved colon inflammation and hyperalgesia, potentially by suppressing the sprouting of sympathetic nerve fibers into the L6 DGR and neurogenic inflammation via deactivating the TRPV1/CGRP, ERK, and TLR4 signaling pathways.


Asunto(s)
Colitis , Electroacupuntura , Neuralgia , Dolor Nociceptivo , Ratas , Animales , Ratas Sprague-Dawley , Hiperalgesia/metabolismo , Electroacupuntura/métodos , Ganglios Espinales/metabolismo , Péptido Relacionado con Gen de Calcitonina/metabolismo , Inflamación Neurogénica/metabolismo , Receptor Toll-Like 4/metabolismo , Neuralgia/metabolismo , Dolor Nociceptivo/metabolismo
4.
Appl Opt ; 58(17): 4642-4646, 2019 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-31251283

RESUMEN

Aiming to implement a low-cost single-photodetector-based NIR micro-spectrometer, we present a novel flame retardant 4 (FR4)-driven micro-grating for spectral dispersion and spatial scanning. It consists of a silicon blazed grating directly bonded onto the FR4 actuator platform and an integrated differential electromagnetic angle sensor. Owing to the better shock and vibration reliability, larger aperture, shorter fabrication cycle, and much lower cost, it may be a potential alternative to conventional silicon microelectromechanical systems scanning micro-gratings. The micro-spectrometer prototype based on this device shows a spectral range of 800-1800 nm, a spectral accuracy of ±1.3 nm, and a 10 nm spectral resolution.

5.
Sensors (Basel) ; 17(2)2017 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-28212325

RESUMEN

Contact time is one of the most important properties for inertial micro-switches. However, it is usually less than 20 µs for the switch with rigid electrode, which is difficult for the external circuit to recognize. This issue is traditionally addressed by designing the switch with a keep-close function or flexible electrode. However, the switch with keep-close function requires an additional operation to re-open itself, causing inconvenience for some applications wherein repeated monitoring is needed. The switch with a flexible electrode is usually fabricated by electroplating technology, and it is difficult to realize low-g switches (<50 g) due to inherent fabrication errors. This paper reports a contact enhancement using squeeze-film damping effect for low-g switches. A vertically driven switch with large proof mass and flexible springs was designed based on silicon micromachining, in order to achieve a damping ratio of 2 and a threshold value of 10 g. The proposed contact enhancement was investigated by theoretical and experimental studies. The results show that the damping effect can not only prolong the contact time for the dynamic acceleration load, but also reduce the contact bounce for the quasi-static acceleration load. The contact time under dynamic and quasi-static loads was 40 µs and 570 µs, respectively.

6.
Chin J Integr Med ; 30(2): 152-162, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38038835

RESUMEN

OBJECTIVE: To investigate whether electroacupuncture (EA) at sensitized acupoints could reduce sympathetic-sensory coupling (SSC) and neurogenic inflammatory response by interfering with 5-hydroxytryptamine (5-HT)ergic neural pathways to relieve colitis and somatic referred pain, and explore the underlying mechanisms. METHODS: Rats were treated with 5% dextran sodium sulfate (DSS) solution for 7 days to establish a colitis model. Twelve rats were randomly divided into the control and model groups according to a random number table (n=6). According to the "Research on Rat Acupoint Atlas", sensitized acupoints and non-sensitized acupoints were determined. Rats were randomly divided into the control, model, Zusanli-EA (ST 36), Dachangshu-EA (BL 25), and Xinshu (BL 15) groups (n=6), as well as the control, model, EA, and EA + GR113808 (a 5-HT inhibitor) groups (n=6). The rats in the control group received no treatment. Acupuncture was administered on 2 days after modeling using the stimulation pavameters: 1 mA, 2 Hz, for 30 min, with sparse and dense waves, for 14 consecutive days. GR113808 was injected into the tail vein at 5 mg/kg before EA for 10 min for 7 consecutive days. Mechanical sensitivity was assessed with von Frey filaments. Body weight and disease activity index (DAI) scores of rats were determined. Hematoxylin and eosin staining was performed to observe colon histopathology. SSC was analyzed by immunofluorescence staining. Immunohistochemical staining was performed to detect 5-HT and substance P (SP) expressions. The calcitonin gene-related peptide (CGRP) in skin tissue and tyrosine hydroxylase (TH) protein levels in DRG were detected by Western blot. The levels of hyaluronic acid (HA), bradykinin (BK), prostaglandin I2 (PGI2) in skin tissue, 5-HT, tryptophan hydroxylase 1 (TPH1), serotonin transporters (SERT), 5-HT 3 receptor (5-HT3R), and 5-HT 4 receptor (5-HT4R) in colon tissue were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: BL 25 and ST 36 acupoints were determined as sensitized acupoints, and BL 15 acupoint was used as a non-sensitized acupoint. EA at sensitized acupoints improved the DAI score, increased mechanical withdrawal thresholds, and alleviated colonic pathological damage of rats. EA at sensitized acupoints reduced SSC structures and decreased TH and CGRP expression levels (P<0.05). Furthermore, EA at sensitized acupoints reduced BK, PGI2, 5-HT, 5-HT3R and TPH1 levels, and increased HA, 5-HT4R and SERT levels in colitis rats (P<0.05). GR113808 treatment diminished the protective effect of EA at sensitized acupoints in colitis rats (P<0.05). CONCLUSION: EA at sensitized acupoints alleviated DSS-induced somatic referred pain in colitis rats by interfering with 5-HTergic neural pathway, and reducing SSC inflammatory response.


Asunto(s)
Colitis , Electroacupuntura , Indoles , Sulfonamidas , Ratas , Animales , Ratas Sprague-Dawley , Serotonina , Puntos de Acupuntura , Dolor Referido , Péptido Relacionado con Gen de Calcitonina , Transducción de Señal , Colitis/inducido químicamente , Colitis/complicaciones , Colitis/terapia
7.
Sci Rep ; 13(1): 2291, 2023 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-36759709

RESUMEN

The excitation technology for high-g-level shock environment experiments is currently a topic of interest, for which velocity amplification by collisions of vertically stacked bodies has been used to develop high-g shock tests with great success. This study investigated the superelastic collision effects generated during high-velocity one-dimensional three-body impacts. Theoretical formulae were derived in brief for an analytical investigation of the collisions. Four experiments were performed with different initial velocities obtained from free-falls from different heights. Velocity gains larger than 5 were obtained for the three-body collisions, and coefficients of restitution larger than 2.5 were observed for the second impact. The experimental results well verified the existence of superelastic collision effects in the one-dimensional three-body impacts.

8.
Rev Sci Instrum ; 94(3): 035114, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-37012759

RESUMEN

The shock tester based on a three-body, single-level velocity amplifier is especially suitable for high-g shock tests of lightweight and compact pieces. This study focuses on disclosing some key technologies that affect whether the velocity amplifier could achieve a high-g level shock experimental environment. Equations describing the first collision are deduced and some key design criteria are proposed. The key conditions for formation of the opposite collision are proposed for the second collision, which is the most important point, to obtain a high-g shock environment. A test platform was constructed, and experiments were conducted with different shock rods, pulse shapers, and initial velocities. The test results fully demonstrated the powerful ability of the single-level velocity amplifier for high-g shock experiments and tell us that a duralumin alloy or carbon fiber is suitable to design shock rods.

9.
BMJ Open ; 13(6): e070130, 2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-37263682

RESUMEN

OBJECTIVE: To evaluate the current state of family doctor contract services (FDCS) in Beijing, identify the roles of family doctors who have worked with disabled older adults and investigate the barriers and facilitators faced by family doctors in providing care for them. DESIGN: A convergent mixed methods study was carried out from October 2020 to January 2021 to collect and analyse both quantitative and qualitative data. The integration strategies in this study were connecting the results of the quantitative phase to data collection of the qualitative phase. SETTING: A multi-stage sampling strategy was used to select 15 community health centres (CHCs) in four districts of Beijing. Of the four districts, two were from urban areas and two were from rural areas. PARTICIPANTS: The inclusion criteria for participants were (1) family doctors, (2) contracted with disabled older adults, (3) engaged in related work for disabled older adults more than 6 months. METHODS: A cluster sampling of 283 family doctors was used in the questionnaire. A purposive sample of 30 family doctors from the same CHCs was selected during the same period. Frequency and rank, rank-sum test, Kruskal-Wallis test were conducted in qualitative data analysis, the views of the interviewees were analysed through the thematic framework method. RESULTS: Currently, family doctors provided various services to satisfy the health needs of disabled older adults, while the usage of FDCS for disabled older adults is affected by many factors. The differences of the importance of family doctors' role (p<0.001) and service satisfaction (p=0.004) were significant among four districts. Compared with contracted health senior citizens, this study has identified five unique roles of family doctors, including 'psychological consultant', 'rehabilitation physiotherapist', 'health educator', 'health manager' and 'family health guardian'. Moreover, family doctors are confronted with a myriad of barriers (including high risks in the process of home visits, a lack of supervisory and incentive mechanisms, insufficiency of time and energy, etc) and facilitators (including establishing a doctor-patient trust relationship, developing humanistic care services, etc) in the FDCS for disabled older adults. CONCLUSIONS: Family doctors play a pivotal role in the FDCS for disabled older adults, while the effect and quality of FDCS in China needs to be improved. It is suggested that further research needs to focus on solving existing barriers of FDCS to optimise the health of disabled older adults and improve the quality of their lives.


Asunto(s)
Servicios Contratados , Médicos de Familia , Humanos , Anciano , Beijing , China , Encuestas y Cuestionarios
10.
BMC Prim Care ; 23(1): 186, 2022 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-35883031

RESUMEN

BACKGROUND: Currently, population aging has been an obstacle and the spotlight for all countries. Compared with developed countries, problems caused by China's aging population are more prominent. Beijing, as a typical example, is characterized by advanced age and high disability rate, making this capital city scramble to take control of this severe problem. The main types of care for the disabled elderly are classified as home care, institutional care, and community care. With the obvious shortage of senior care institutions, most disabled elderly people are prone to choose home care. This kind of elderly care model is in line with the traditional Chinese concept and it can save the social cost of the disabled elderly to the greatest extent. However, home care for the disabled elderly is facing bumps from the whole society, such as lack of professional medical care, social support and humanistic care, and the care resources provided by a single subject cannot meet the needs of the disabled elderly. OBJECTIVE: Based on the demands of the disabled elderly and their families, this study aims to explore the current status of home care service, look for what kind of care is more suitable for the disabled elderly, and try to find an appropriate elderly care mechanism which could meet the diverse needs of the disabled elderly. METHODS: A total of 118 disabled elderly people and their primary caregivers were selected from four districts of Beijing by using multi-stage stratified proportional sampling method. A one-to-one and semi-structured in-depth qualitative interview were conducted in the study to find out the health status of the disabled elderly, the relationship between the disabled elderly and their primary caregivers, and utilization of elderly care resources, etc. The views of the interviewees were analyzed through the thematic framework method. All the methods were carried out in accordance with relevant guidelines and regulations. RESULTS: The results showed that the average age of 118 disabled elderly is 81.38 ± 9.82 years; 86 (72.9%) are severe disability; 105 (89.0%)are plagued by chronic diseases; the average duration of disability is 5.63 ± 5.25 years; most of disabled elderly have 2 children, but the primary caregiver are their own partner (42, 35.6%), and there is an uneven sharing of responsibilities among the disabled elderly's offspring in the process of home care. The disabled elderly enjoy medical care services, rehabilitation training, daily health care, psychological and other demands. However, the disabled elderly and their families in Beijing face a significant financial burden, as well as physical and psychological issues. The care services provided by the government, family doctors, family members and social organizations fall far short of satisfying the diverse care needs of the disabled elderly. CONCLUSIONS: In order to effectively provide home care services for the disabled elderly, it is therefore necessary to establish a coordination mechanism of multiple subjects and give full play to the responsibilities of each subject. This study proposes a strengthening path for the common cooperation of multiple subjects, which taking specific responsibilities and participating in the home care for the disabled elderly: (1) The government should give full play to the top-level leading responsibilities and effectively implement people-oriented measures to the disabled elderly. (2) Family doctors strengthen their responsibilities as health gatekeepers and promote continuous health management of the disabled elderly. (3) Family members assume the main responsibility and provide a full range of basic care services. (4) Social forces promote supplementary responsibilities of public welfare and expand the connotation of personalized care services. (5) The disabled elderly should shoulder appropriate personal responsibility and actively cooperate with other subjects.


Asunto(s)
Niños con Discapacidad , Servicios de Atención de Salud a Domicilio , Anciano , Anciano de 80 o más Años , Beijing , Niño , Humanos , Investigación Cualitativa , Apoyo Social
11.
Front Cell Infect Microbiol ; 12: 1044770, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36506032

RESUMEN

Purpose: 2019 Coronavirus disease (COVID-19) is endangering health of populations worldwide. Latest research has proved that Lianhua Qingwen granules (LHQW) can reduce tissue damage caused by inflammatory reactions and relieve patients' clinical symptoms. However, the mechanism of LHQW treats COVID-19 is currently lacking. Therefore, we employed computer simulations to investigate the mechanism of LHQW treats COVID-19 by modulating inflammatory response. Methods: We employed bioinformatics to screen active ingredients in LHQW and intersection gene targets. PPI, GO and KEGG was used to analyze relationship of intersection gene targets. Molecular dynamics simulations validated the binding stability of active ingredients and target proteins. Binding free energy, radius of gyration and the solvent accessible surface area were analyzed by supercomputer platform. Results: COVID-19 had 4628 gene targets, LHQW had 1409 gene targets, intersection gene targets were 415. Bioinformatics analysis showed that intersection targets were closely related to inflammation and immunomodulatory. Molecular docking suggested that active ingredients (including: licopyranocoumarin, Glycyrol and 3-3-Oxopropanoic acid) in LHQW played a role in treating COVID-19 by acting on CSF2, CXCL8, CCR5, NLRP3, IFNG and TNF. Molecular dynamics was used to prove the binding stability of active ingredients and protein targets. Conclusion: The mechanism of active ingredients in LHQW treats COVID-19 was investigated by computer simulations. We found that active ingredients in LHQW not only reduce cell damage and tissue destruction by inhibiting the inflammatory response through CSF2, CXCL8, CCR5 and IFNG, but also regulate cell survival and growth through NLRP3 and TNF thereby reducing apoptosis.


Asunto(s)
COVID-19 , Simulación de Dinámica Molecular , Humanos , Simulación del Acoplamiento Molecular , Supervivencia Celular , Biología Computacional
12.
BMC Health Serv Res ; 10: 69, 2010 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-20298613

RESUMEN

BACKGROUND: Migrant workers are a unique phenomenon in the process of China's economic transformation. The household registration system classifies them as temporary residents in cities, putting them in a vulnerable state with an unfair share of urban infrastructure and social public welfare. The amount of pressure inflicted by migrant workers in Beijing, as one of the major migration destinations, is currently at a threshold. This study was designed to assess the factors associated with health-seeking behavior and to explore feasible solutions to the obstacles migrant workers in China faced with when accessing health-care. METHODS: A sample of 2,478 migrant workers in Beijing was chosen by the multi-stage stratified cluster sampling method. A structured questionnaire survey was conducted via face-to-face interviews between investigators and subjects. The multilevel methodology (MLM) was used to demonstrate the independent effects of the explanatory variables on health seeking behavior in migrant workers. RESULTS: The medical visitation rate of migrant workers within the past two weeks was 4.8%, which only accounted for 36.4% of those who were ill. Nearly one-third of the migrant workers chose self-medication (33.3%) or no measures (30.3%) while ill within the past two weeks. 19.7% of the sick migrants who should have been hospitalized failed to receive medical treatment within the past year. According to self-reported reasons, the high cost of health service was a significant obstacle to health-care access for 40.5% of the migrant workers who became sick. However, 94.0% of the migrant workers didn't have any insurance coverage in Beijing. The multilevel model analysis indicates that health-seeking behavior among migrants is significantly associated with their insurance coverage. Meanwhile, such factors as household monthly income per capita and working hours per day also affect the medical visitation rate of the migrant workers in Beijing. CONCLUSION: This study assesses the influence of socio-demographic characteristics on the migrant workers' decision to seek health care services when they fall ill, and it also indicates that the current health service system discourages migrant workers from seeking appropriate care of good quality. Relevant policies of public medical insurance and assistance program should be vigorously implemented for providing affordable health care services to the migrants. Feasible measures need to be taken to reduce the health risks associated with current hygiene practices and equity should be assured in access to health care services among migrant workers.


Asunto(s)
Servicios de Salud/economía , Servicios de Salud/estadística & datos numéricos , Aceptación de la Atención de Salud , Migrantes/psicología , China , Ciudades , Encuestas de Atención de la Salud , Conocimientos, Actitudes y Práctica en Salud , Humanos , Renta , Entrevistas como Asunto , Pacientes no Asegurados , Encuestas y Cuestionarios
13.
Artículo en Inglés | MEDLINE | ID: mdl-33212868

RESUMEN

OBJECTIVE: To evaluate the degree to which electronic medical records (EMRs) were used in primary care and the value of EMRs as perceived by primary care workers in China. METHODS: A cross-sectional survey was conducted on 2719 physicians (n = 2213) and nurses (n = 506) selected from 462 community health centres across all regions of mainland China except for Tibet. Regional differences in the responses regarding the functionality of existing EMR systems and the perceived value of EMRs were examined using Chi-square tests and ordinal regression analyses. RESULTS: Less than 59% of the community health centres had adopted EMRs. More than 89% of the respondents believed that it was necessary to adopt EMRs in primary care. Of the existing EMR systems, 50% had access to telehealth support for laboratory, imaging or patient consultation services. Only 38.4% captured data that met all task needs and 35.4% supported referral arrangements. "Management of chronic conditions" was voted (66%) as the top preferred feature of EMRs. Higher levels of recognition of the value of EMRs were found in the relatively more developed eastern region compared with their counterparts in other regions. CONCLUSIONS: Rapid EMR adoption in primary care is evident in mainland China. The low level of functionality in data acquisition and referral arrangements runs counter to the requirements for "management of chronic conditions", the most preferred feature of EMRs in primary care. Regional disparities in the realised value of EMRs in primary care deserve policy attention.


Asunto(s)
Servicios de Salud Comunitaria , Agentes Comunitarios de Salud , Registros Electrónicos de Salud , China , Servicios de Salud Comunitaria/estadística & datos numéricos , Agentes Comunitarios de Salud/psicología , Agentes Comunitarios de Salud/estadística & datos numéricos , Estudios Transversales , Registros Electrónicos de Salud/estadística & datos numéricos , Femenino , Humanos , Masculino , Percepción , Atención Primaria de Salud/estadística & datos numéricos , Tibet
14.
Micromachines (Basel) ; 9(11)2018 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-30715038

RESUMEN

Our previous report based on a 10 g (gravity) silicon-based inertial micro-switch showed that the contact effect between the two electrodes can be improved by squeeze-film damping. As an extended study toward its potential applications, the switch with a large proof mass suspended by four flexible serpentine springs was redesigned to achieve 5 g threshold value and enhanced threshold accuracy. The impact of the squeeze-film damping on the threshold value was theoretically studied. The theoretical results show that the threshold variation from the designed value due to fabrication errors can be reduced by optimizing the device thickness (the thickness of the proof mass and springs) and then establishing a tradeoff between the damping and elastic forces, thus improving the threshold accuracy. The design strategy was verified by FEM (finite-element-method) simulation and an experimental test. The simulation results show that the maximum threshold deviation was only 0.15 g, when the device thickness variation range was 16⁻24 µm, which is an adequately wide latitude for the current bulk silicon micromachining technology. The measured threshold values were 4.9⁻5.8 g and the device thicknesses were 18.2⁻22.5 µm, agreeing well with the simulation results. The measured contact time was 50 µs which is also in good agreement with our previous work.

15.
Micromachines (Basel) ; 7(12)2016 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-30404409

RESUMEN

Squeeze-film damping and acceleration load are two major issues in the design of inertial micro-switches. In order to deeply and systematically study these two issues, this paper proposes a typical vertically-driven inertial micro-switch, wherein the air and electrode gaps were chosen to design the required damping ratio and threshold value, respectively. The switch was modeled by ANSYS Workbench, and the simulation program was optimized for computational accuracy and speed. Transient analysis was employed to investigate the relationship between the damping ratio, acceleration load, and the natural frequency, and the dynamic properties (including contact bounce, contact time, response time, and threshold acceleration) of the switch. The results can be used as a guide in the design of inertial micro-switches to meet various application requirements. For example, increasing the damping ratio can prolong the contact time of the switch activated by short acceleration duration or reduce the contact bounce of the switch activated by long acceleration duration; the threshold value is immune to variations in the damping effect and acceleration duration when the switch is quasi-statically operated; the anti-jamming capability of the switch can be improved by designing the sensing frequency of the switch to be higher than the acceleration duration but much lower than the other order frequencies of the switch.

16.
Zhonghua Liu Xing Bing Xue Za Zhi ; 24(8): 684-8, 2003 Aug.
Artículo en Zh | MEDLINE | ID: mdl-14521788

RESUMEN

OBJECTIVE: To study the annual incidence of injuries and the relationship between behavior problems and injuries among school-age children. METHODS: A prospective cohort study on injuries for 1-year follow-up period was conducted among 2 005 school-age children selected by cluster sampling from three primary schools in Maanshan city. They subjects were divided into two groups with or without exposure according to behavior problems rated by the Rutter Child Behavior Questionnaire at the beginning of the study. Nonparametric test was performed to analyze the differences in injuries between the two groups of children, and the influential factors for injuries were analyzed with multi-classification ordinal response variable logistic regression model. RESULTS: The overall incidence rate for injuries in school-age children was 42.51%, while among children with and without behavior problems were 64.87% and 38.85%, respectively. There were significant differences between the two groups (u = -6.054, P = 0.000). However, the incidence rates of injuries in school-age children with antisocial (A) behavior, neurotic (N) behavior and mixed (M) behavior were 66.99%, 67.41% and 61.40%, respectively. No significant differences were found among them (u(A,N) = -0.052, P = 0.958; u(A,M) = -0.400, P = 0.689; u(N,M) = -0.364, P = 0.716). Multivariate analysis indicated that injuries in school-age children were associated with children behavior problems, maternal age at childbirth, bad conditions during mother pregnancy, education background of mother, prevention measures for safety at home and the child accompanied to travel between school and home by adults. Behavior problems of children seemed to be the major risk factors for injuries. CONCLUSION: Children with behavior problems represented a significant risk group for injuries among school-age children. When planning intervention strategies on injuries, behavior problems should be emphasized to ensure optimal effectiveness of intervention.


Asunto(s)
Conducta Infantil , Heridas y Lesiones/epidemiología , Niño , Conducta Infantil/psicología , China/epidemiología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Modelos Logísticos , Masculino , Estudios Prospectivos
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