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This meta-analysis of randomized controlled trials (RCTs) was conducted to explore the effects of flavonoid intake on adiponectin and leptin levels. The PubMed, EMBASE, and Cochrane Library databases were searched on March 1, 2021. Random-effects, subgroup, sensitivity, and meta-regression analyses were conducted on 40 publications. Flavonoid intake significantly increased circulating adiponectin (0.54 µg/ml, 95% CI [0.20, 0.88], p = .002; I2 = 86.4%) and significantly reduced leptin levels (weighted mean difference: -0.79 ng/ml, 95% CI [-1.33, -0.25], p = .004; I2 = 87.7%). Subgroup analysis demonstrated that flavonoid intervention produced a significant elevation in adiponectin levels only in studies that lasted more than 12 weeks, conducted in Asian regions, were parallel-designed, involved obese or overweight participants and participants with type 2 diabetes mellitus (T2DM) or cardiovascular diseases, used tea catechins, and used a dietary supplement intervention. A significantly negative effect on leptin levels was observed in studies conducted in Asian countries, with healthy participants and participants with T2DM, used whole food interventions, and involved participants with lower baseline leptin levels. In conclusion, flavonoid intake significantly increased circulating adiponectin and decreased leptin levels; however, study heterogeneity was very high. Future well-designed trials are required to address heterogeneous study designs and clarify the efficacy of plants in regulating adiponectin and leptin levels.
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Adiponectina , Diabetes Mellitus Tipo 2 , Humanos , Adiponectina/uso terapéutico , Leptina/uso terapéutico , Flavonoides/farmacología , Flavonoides/uso terapéutico , Obesidad , Diabetes Mellitus Tipo 2/tratamiento farmacológicoRESUMEN
Intraoperative monitoring is essential for providing safe and effective care during open surgery. In this paper, numerical simulation is performed to track the flow and heat transfer of carotid arteries with and without atherosclerotic plaque in a real physiological system during surgery, in which the heat transport is first considered to couple to the blood flow due to the temperature dependence of the blood viscosity. The impacts of the operating room temperature and hematocrit (H) on the viscosity, velocity, temperature, wall shear stress (WSS), pressure drop and oscillation are investigated. The results demonstrate that the presence of plaque in the carotid artery induces a greater blood flow velocity, pressure drop, WSS, and oscillation, as well as a smaller viscosity and temperature variations. A decreasing ambient temperature leads to a decrease in the temperature and an increase in the low-WSS area, which implies a greater risk of hypothermia and atherosclerosis. As H increases, the high-WSS areas substantially expand; when H varies from 65% to 80%, WSSave increases by 70.02% and 68.57% for the arteries with and without plaque, respectively, which indicates a higher risk of vascular injury. The results obtained can serve as a guideline regarding the selection of an operating room temperature for carotid disease patients with distinct hematocrits.
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Arterias Carótidas/fisiología , Enfermedades de las Arterias Carótidas/fisiopatología , Hemodinámica , Modelos Teóricos , Placa Aterosclerótica/fisiopatología , Conductividad Térmica , Arterias Carótidas/fisiopatología , Arterias Carótidas/cirugía , Enfermedades de las Arterias Carótidas/cirugía , Hematócrito , Humanos , Periodo Intraoperatorio , Quirófanos , Placa Aterosclerótica/cirugía , TemperaturaRESUMEN
Since 2011, Zhejiang province has eliminated iodine deficiency disorders (IDD) in its populations. Following this achievement, a new revised iodine concentration in iodised salt was implemented in Zhejiang in 2012. However, the re-emergence of iodine deficiency has been reported in pregnant women. Therefore, the aim of this study was to assess household salt iodine concentration and iodine status of pregnant women in Zhejiang province, China. We conducted a cross-sectional study between April 2018 and August 2018 in Quzhou, Zhejiang province. Pregnant women aged ≥ 18 years who did not have a history of thyroid disease were recruited into the study. They were asked to complete socio-demographic questionnaires including a food frequency questionnaire (FFQ). In addition, a spot urine sample and a household table salt sample were also provided by each participant. A total of 625 pregnant women agreed to participate. The overall median urinary iodine concentration (UIC) was 130 µg/L, indicating mild-to-moderate iodine deficiency in pregnant women. The coverage of iodised salt was 85.2%, and of these, the rate of adequately iodised salt was 98.1%. In conclusion, our results confirmed the re-emergence of iodine deficiency in pregnant women as reported by other studies conducted in Zhejiang province. Therefore, urgent public health actions are needed to improve iodine status of pregnant women in order to prevent the adverse consequences of IDD on the neurodevelopment of foetus.
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Yodo/deficiencia , Cloruro de Sodio Dietético/análisis , Adolescente , Adulto , China , Estudios Transversales , Composición Familiar , Femenino , Humanos , Yodo/análisis , Yodo/sangre , Persona de Mediana Edad , Embarazo , Complicaciones del Embarazo/etiología , Factores Socioeconómicos , Encuestas y Cuestionarios , Adulto JovenRESUMEN
BACKGROUND: Autophagy is a cellular degradation process that is highly evolutionarily-conserved in yeast, plants, and animals. In plants, autophagy plays important roles in regulating intracellular degradation and recycling of amino acids in response to nutrient starvation, senescence, and other environmental stresses. Foxtail millet (Setaria italica) has strong resistance to stresses and has been proposed as an ideal material for use in the study of the physiological mechanisms of abiotic stress tolerance in plants. Although the genome sequence of foxtail millet (Setaria italica) is available, the characteristics and functions of abiotic stress-related genes remain largely unknown for this species. RESULTS: A total of 37 putative ATG (autophagy-associated genes) genes in the foxtail millet genome were identified. Gene duplication analysis revealed that both segmental and tandem duplication events have played significant roles in the expansion of the ATG gene family in foxtail millet. Comparative synteny mapping between the genomes of foxtail millet and rice suggested that the ATG genes in both species have common ancestors, as their ATG genes were primarily located in similar syntenic regions. Gene expression analysis revealed the induced expression of 31 SiATG genes by one or more phytohormone treatments, 26 SiATG genes by drought, salt and cold, 24 SiATG genes by darkness and 25 SiATG genes by nitrogen starvation. Results of qRT-PCR showing that among 37 SiATG genes, the expression level of SiATG8a was the highest after nitrogen starvation treatment 24 h, suggesting its potential role in tolerance to nutrient starvation. Moreover, the heterologous expression of SiATG8a in rice improved nitrogen starvation tolerance. Compared to wild type rice, the transgenic rice performed better and had higher aboveground total nitrogen content when the plants were grown under nitrogen starvation conditions. CONCLUSIONS: Our results deepen understanding about the characteristics and functions of ATG genes in foxtail millet and also identify promising new genetic resources that should be of use in future efforts to develop varieties of foxtail millet and other crop species that have resistance to nitrogen deficiency stress.
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Familia de las Proteínas 8 Relacionadas con la Autofagia/genética , Autofagia/genética , Regulación de la Expresión Génica de las Plantas , Estudio de Asociación del Genoma Completo , Nitrógeno/metabolismo , Oryza/genética , Setaria (Planta)/genética , Familia de las Proteínas 8 Relacionadas con la Autofagia/metabolismo , Mapeo Cromosómico , Biología Computacional/métodos , Exones , Duplicación de Gen , Perfilación de la Expresión Génica , Intrones , Oryza/clasificación , Fenotipo , Filogenia , Setaria (Planta)/clasificación , Estrés FisiológicoRESUMEN
Cleft palate is caused by the failure of palatal midline epithelial cells to disintegrate, which is necessary for palatal mesenchymal confluence. Although 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure is linked to cleft palate at a high rate, the mechanism remains to be elucidated. The present study was designed to determine the effects of TCDD on the fate of epithelial cell isolated from human fetal palatal shelves (hFPECs). We demonstrate that TCDD increased cell proliferation and promoted the progression of cells from G1 to S phase as well as increased the number of cells entering the G2/M phase. We found that TCDD has no measurable effect on apoptosis of hFPECs. The protein level assays revealed that TCDD increased cyclin-dependent kinases 4 (cdk4), cyclin D1, cyclin E and p21 (Waf1/Cip1) but not cdk2, bcl-2, cyclin B1 and cyclin A. Furthermore, TCDD activated PI3K/AKT signaling, and the PI3K inhibitor, LY294002, partially abrogated TCDD-induced cell proliferation and gene modulations. TCDD treatment increased CYP1A1 mRNA and protein levels, which indicated the activation of AhR signaling. Knockdown of the AhR with siRNA suppressed TCDD-induced cell proliferation and PI3K/AKT signaling activation. Taken together, these data demonstrated that TCDD is able to promote growth of hFPECs through AhR-dependent activation of the PI3K/AKT pathway, which may account for the underlying mechanism by which TCDD causes a failure of palatal fusion.
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Células Epiteliales/efectos de los fármacos , Hueso Paladar/citología , Dibenzodioxinas Policloradas/toxicidad , Receptores de Hidrocarburo de Aril/genética , Proteínas de Ciclo Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Células Epiteliales/metabolismo , Feto , Humanos , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Mensajero/metabolismo , ARN Interferente Pequeño/genéticaRESUMEN
One critical step of second palatal fusion is the newly formed medial epithelia seam (MES) disintegration, which involves apoptosis, epithelial to mesenchymal transition (EMT), and cell migration. Although the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate at high rates, little is known about the effects of TCDD exposure on the fate of palatal epithelial cells. By using primary epithelial cells isolated from human fetal palatal shelves (hFPECs), we show that TCDD increased cell proliferation and EMT, as demonstrated by increased the epithelial markers (E-cadherin and cytokeratin14) and enhanced the mesenchymal markers (vimentin and fibronectin), but had no effect on cell migration and apoptosis. TCDD exposure led to a dose-dependent increase in Slug protein expression. Coimmunoprecipitation revealed that TCDD promoted AhR to form a protein complex with Slug. ChIP assay confirmed that TCDD exposure recruited AhR to the xenobiotic responsive element of Slug promoter. Knockdown of AhR by siRNA remarkably weakened TCDD-induced binding of AhR to the XRE promoter of slug, thereby suppressed TCDD-induced vimentin. Further experiment showed that TCDD stimulated EGFR phosphorylation did not influence the TGFß3/Smad signaling; whereas TCDD increased phosphorylation of ERK1/2 and p38 with no effect on activation of JNK. By using varieties of inhibitors, we confirmed that TCDD promoted proliferation and EMT of hFPECs via activation of EGFR/ERK pathway. These data make a novel contribution to the molecular mechanism of cleft palate by TCDD.
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Transición Epitelial-Mesenquimal/efectos de los fármacos , Receptores ErbB/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Hueso Paladar/efectos de los fármacos , Dibenzodioxinas Policloradas/toxicidad , Receptores de Hidrocarburo de Aril/metabolismo , Apoptosis/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Humanos , Inmunoprecipitación , Hueso Paladar/citología , Hueso Paladar/embriología , Hueso Paladar/metabolismo , Cultivo Primario de Células , Unión Proteica , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Hidrocarburo de Aril/antagonistas & inhibidoresRESUMEN
A space-resolved vacuum ultraviolet (VUV) spectroscopy using a 3 m normal incidence spectrometer has been developed to measure the impurity profile in the edge ergodic layer composed of stochastic magnetic field by which the edge plasma in the large helical device (LHD) is uniquely characterized. It vertically measures the spatial profile of VUV lines emitted from impurities in the wavelength range of 300-3200 Å. The wavelength interval, Δλ, which can be measured in a single discharge, is about 37 Å. A spectral resolution of 0.153 Å, which results from an entrance slit width of the spectrometer of 20 µm, is adopted. The vertical observation range, ΔZ, can be switched by taking a convex mirror in and out, which enables both the edge profile measurement focused on the ergodic layer and the full profile measurement covering an entire vertical size of the LHD plasma, e.g., 165 ≤ ΔZ ≤ 200 mm and 1000 ≤ ΔZ ≤ 1250 mm for the R(ax)=3.6 m configuration, respectively, which shows a slight wavelength dependence. Precise calibrations on the line dispersion, spectral resolution, vertical range of the observable region, and the spatial resolution have been performed with a unique method. As a preliminary result, the ion temperature profile is obtained for CIV at 1548.20 Å in the second order (denoted as 1548.20 × 2 Å) in high-density helium discharges in addition to the emission profile with a time resolution of 100 ms in a multitrack CCD operation mode. The poloidal flow in the ergodic layer based on the Doppler-shift measurement of CIV at 1548.20 × 2 Å is also observed in high-density hydrogen discharges.
RESUMEN
A space-resolved vacuum ultraviolet (VUV) spectroscopy using a 3 m normal incidence spectrometer has been developed to measure the impurity profile in the edge ergodic layer composed of stochastic magnetic field by which the edge plasma in the large helical device (LHD) is uniquely characterized. It vertically measures the spatial profile of VUV lines emitted from impurities in the wavelength range of 300-3200 Å. The wavelength interval, Δλ, which can be measured in a single discharge, is about 37 Å. A spectral resolution of 0.153 Å, which results from an entrance slit width of the spectrometer of 20 µm, is adopted. The vertical observation range, ΔZ, can be switched by taking a convex mirror in and out, which enables both the edge profile measurement focused on the ergodic layer and the full profile measurement covering an entire vertical size of the LHD plasma, e.g., 165 ≤ ΔZ ≤ 200 mm and 1000 ≤ ΔZ ≤ 1250 mm for the R(ax)=3.6 m configuration, respectively, which shows a slight wavelength dependence. Precise calibrations on the line dispersion, spectral resolution, vertical range of the observable region, and the spatial resolution have been performed with a unique method. As a preliminary result, the ion temperature profile is obtained for CIV at 1548.20 Å in the second order (denoted as 1548.20 × 2 Å) in high-density helium discharges in addition to the emission profile with a time resolution of 100 ms in a multitrack CCD operation mode. The poloidal flow in the ergodic layer based on the Doppler-shift measurement of CIV at 1548.20 × 2 Å is also observed in high-density hydrogen discharges.
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PURPOSE: The present study aimed to explore the clinical characteristics of heparin-induced thrombocytopenia (HIT) after surgery for acute type A aortic dissection and perform a relevant prognostic analysis. METHODS: After continuous observation and analysis of 204 patients who underwent acute type A aortic dissection, we found that blood platelets decreased significantly after surgery and that these patients can be suspected to suffer HIT based on relevant 4Ts scores. For these suspected HIT patients, a latex particle-enhanced immunoturbidimetric assay was conducted to detect heparin-induced antibodies. Perioperative clinical data of patients in HIT and non-HIT groups were recorded as were blood platelet counts, HIT antibody test results, 4Ts scores, thromboembolic complications, clinical prognosis and outcomes. RESULTS: In the present study, 38 suspected HIT patients, 16 HIT patients and 188 non-HIT patients were selected in the clinical setting. Among them, HIT patients were found to have prolonged cardiopulmonary bypass time (223 min on average vs. 164 min) and delayed aortic cross-clamp time (128 min on average vs. 107 min), and these differences between HIT patients and non-HIT patients were significant (P < 0.05). Additionally, the HIT group required longer operation time and higher dose of heparin, but showing no statistical differences (P > 0.05). The transfusions of blood platelets in the HIT group and non-HIT group were 18.7 ± 5.0u and 15.6 ± 7.34 u, respectively. In the HIT group, the mechanic ventilation time and the length of ICU stay were longer comparing the non-HIT group(P < 0.05), though no significant differences in total length of stay or In-hospital mortality were observed (P > 0.05). The incidence of continuous renal replacement therapy in HIT group was higher than the non-HIT group (P < 0.05). Additionally,there were no significant differences in 24-h postoperative drainage or reoperation for bleeding in both group(P > 0.05). However, the HIT antibody titer in the HIT group was significantly higher than that in the Suspected HIT group (2.7 ± 0.8 U/mL vs. 0.3 ± 0.2 U/mL) (P < 0.05). Among patients diagnosed with HIT, the incidence of thromboembolism reached 31.5%.For example, two HIT patients newly developed thromboembolism in both lower extremities,and three patients experienced cerebral infarction. CONCLUSIONS: After surgery for acute type A aortic dissection, HIT patients developed postoperative complications, the duration of ventilatory support and length of ICU stay were extended, and the incidence of thromboembolism increased. HIT antibody detection and risk classification should be implemented for high-risk patients showing early clinical characteristics.
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Anticoagulantes/efectos adversos , Aneurisma de la Aorta/cirugía , Disección Aórtica/cirugía , Heparina/efectos adversos , Complicaciones Posoperatorias/inducido químicamente , Trombocitopenia/inducido químicamente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/fisiopatología , Complicaciones Posoperatorias/prevención & control , Pronóstico , Estudios Prospectivos , Medición de Riesgo , Trombocitopenia/diagnóstico , Trombocitopenia/fisiopatología , Trombocitopenia/prevención & controlRESUMEN
BACKGROUND AND OBJECTIVE: Nanoparticle-mediated targeted drug delivery is a promising option for treatment of atherosclerosis. However, the drug targeting may be affected by multiple factors. Considerable attentions have been focused on the influences of external factors, e.g., magnetic field, drug-loaded particle, but internal factors, e.g., plaque morphology (stenosis degree and shoulder length), have not received any attention yet. Therefore, we investigate the impact of plaque morphology on magnetic nanoparticles targeting under the action of an external field. METHOD: Numerical simulation, based on Eulerian-Lagrangian coupled Fluid-Solid Interaction, is performed in ANSYS Workbench platform. Blood flow is solved by Navier-Stokes equation, particles are tracked by discrete phase model, and the incorporated effect is obtained by two-way method. Plaques with varying stenosis degrees and shoulder lengths are acquired by manually modifying the geometry of patient-specific. The quantified variables include targeted delivery efficiency (deposition+adhesive strength) of particles and plaque injury characterized by temporal-spatial averaged shear stress (TAWSS¯) during the process of drug transport, in which the critical deposition velocity is determined by plaques and particles, the DEFINE_DPM_BC and User Defined Memory are employed to evaluate whether the particles are deposited, and to store the total number and the adhesive strength of particles deposited on the plaque. RESULTS: Results signify that, with an increment of plaque stenosis degree, the deposition of particle and the adhesive strength between particle and plaque decrease, while the TAWSS¯ increases. Furthermore, for the same stenosis degree, with the increase of plaque shoulder length, the deposition and the adhesive strength of particle increase, and the TAWSS¯ decreases. CONCLUSIONS: Results demonstrates that the plaque with smaller stenosis degree or longer shoulder length may achieve a better treatment effect in view of the higher targeted delivery efficiency of particles and the lighter shear damage to plaque itself during the process of drug transport.
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Aterosclerosis , Hombro , Aterosclerosis/tratamiento farmacológico , Simulación por Computador , Constricción Patológica , Sistemas de Liberación de Medicamentos , HumanosRESUMEN
Normal weight central obesity (NWCO), a distinct phenotype of obesity that is associated with a higher risk of cardiometabolic dysregulation, has received growing attention in the scientific literature. In this study, we aimed to report the prevalence of NWCO in the general Chinese adults and its secular trend from 1993 to 2011. The comorbid cardiometabolic risk of NWCO was also explored. Data from the China Health and Nutrition Survey (CHNS) 1993-2011 were obtained. NWCO was defined as the combination of a BMI of 18.5-23.9 kg/m2 and 1) a waist circumference (WC) of >85 cm in males or >80 cm in females (NWCO by WC); 2) a waist to height ratio (WHtR) of ≥0.5 (NWCO by WHtR); 3) a waist to hip ratio (WHR) of ≥0.9 in males or ≥0.85 in females (NWCO by WHR). We assessed the trend of NWCO prevalence with the generalized estimating equation method. The demographic, socioeconomic, geographic, behavioural and cardiometabolic predictors of NWCO were explored with multivariable logistic regression. From 1993 to 2011, the age-standardized prevalence of NWCO by WC increased from 6.65% (95% CI: 6.09-7.26) to 13.24% (95% CI: 12.58-13.93), and that of NWCO by WHtR and NWCO by WHR rose from 13.18% (95% CI: 12.41-13.98) to 17.06% (95% CI: 16.35-17.79) and from 16.14% (95% CI: 15.3-17.01) to 19.04% (95% CI: 18.25-19.85) respectively. The associated cardiometabolic factors of NWCO (by WC, WHtR and WHR) were hypertension, diabetes, insulin resistance, decreased insulin sensitivity, low high-density lipoprotein and elevated triglyceride. Moreover, NWCO by WC and NWCO by WHtR were associated with a decreased risk of impaired insulin secretion, and NWCO by WC was additionally linked to elevated total cholesterol. The prevalence of NWCO in the general Chinese adults increased significantly from 1993 to 2011. Effective strategies are needed to combat this epidemic and reduce its deleterious health outcomes.
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Índice de Masa Corporal , Peso Corporal , Enfermedades Cardiovasculares/metabolismo , Obesidad Abdominal/metabolismo , Adulto , Anciano , Pueblo Asiatico/estadística & datos numéricos , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etnología , China/epidemiología , Estudios Transversales , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Obesidad Abdominal/epidemiología , Obesidad Abdominal/etnología , Prevalencia , Factores de Riesgo , Análisis Espacio-Temporal , Circunferencia de la Cintura , Relación Cintura-Estatura , Relación Cintura-Cadera , Adulto JovenRESUMEN
BACKGROUND: Studies on the effects of extreme ambient temperature on the risk of adverse birth outcomes are limited, and the results are inconsistent. In this study, we evaluated the short-term effects of daily mean temperature on the risk of premature rupture of membranes (PROM) in Xinxiang, China. METHODS: Daily hospitalization data for PROM, daily meteorological data, and ambient pollution data in Xinxiang from January 1, 2015 to December 31, 2017 were collected. A quasi-Poisson generalized additive model (GAM) combined with a distributed lag non-linear model (DLNM) was applied to assess the short-term impact of temperature on PROM. The model was adjusted for relative humidity, air pollution, time trend, day of the week, and public holidays. RESULTS: The number of daily hospitalizations for PROM during the study period was 3255. With a reference median temperature of 17⯰C, there were significant associations between the temperature deviation from the threshold temperature (2⯰C, 12th percentile; 29⯰C, 91st percentile) and PROM hospitalization at lag 0-2â¯days. Exposure to extreme cold (-2⯰C, 1st percentile) or extreme heat (32⯰C, 99th percentile) were associated with 0.528 (95% confidence interval [CI]: 0.278-0.986) and 2.161 (95% CI: 1.240-3.764) increased risks of PROM, respectively. Younger mothers with age <35â¯years were more sensitive to the impact of extreme temperature. CONCLUSIONS: These findings suggest that heat temperature is associated with higher PROM risk, while cold temperature might be a protective factor against PROM in Xinxiang, China. Given the adverse consequences of PROM and concerns over global climate change, pregnant women should take special precautions in summer when there are sudden increases in temperature.
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Calor Extremo , Rotura Prematura de Membranas Fetales/epidemiología , Exposición Materna/estadística & datos numéricos , Adulto , China/epidemiología , Femenino , Humanos , Embarazo , TemperaturaRESUMEN
A space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 50-500 Å has been developed to measure two-dimensional distribution of impurity spectral lines emitted from edge plasma of Large Helical Device (LHD), in which the magnetic field is formed by stochastic magnetic field with three-dimensional structure called ergodic layer. The two-dimensional measurement of edge impurity line emissions is carried out by scanning horizontally the observation chord of the space-resolved EUV spectrometer during single LHD discharge. Images of CIV (312.4 Å) and HeII (303.78 Å) are presented as the first result. The results are compared with ones calculated from the edge chord length in the ergodic layer of LHD plasma.
RESUMEN
Spectra measured by an extreme ultraviolet (EUV) spectrometer frequently suffer large spike noise when Large Helical Device is operated in low-density range (≤ 3 × 10(13) cm(-3)) with neutral beam injection (NBI). The spike noise completely disappears in electron cyclotron heating discharges. In order to examine the effect of NBI, a carbon filter with thickness of 150 nm was installed in the EUV spectrometer. As a result, the spike noise was reduced by an order of magnitude. It is experimentally verified that the spike noise is caused by escaping high-energy neutral particles resulting from the circulating high-energy hydrogen ions borne from NBI.
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Vertical profile of neon line emissions in 30-650 Å wavelength range has been observed in horizontally elongated plasma cross section of Large Helical Device (LHD). Intensity ratio between the neon line emissions is studied to measure the radial profile of electron temperature in the edge stochastic magnetic field layer of LHD. The edge temperature profile successfully obtained from the line ratio of NeVIII 2s-3p to 2p-3s transitions is compared with the simulation based on three-dimensional edge transport code. The result shows a reasonably good agreement with the edge temperature profile analyzed from atomic data and analysis structure code. The electron temperature at last closed flux surface measured from the intensity ratio is also in good agreement with that measured from Thomson scattering.
RESUMEN
A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 Å is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n(e) ≥ 10(14) cm(-3)) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.