Objective： Vitamin D is a group of fat-soluble molecules that are structurally similar to steroids. Emerging data have led to the hypothesis that Vitamin D plays a role in the regulation of many physiological process...Objective： Vitamin D is a group of fat-soluble molecules that are structurally similar to steroids. Emerging data have led to the hypothesis that Vitamin D plays a role in the regulation of many physiological processes beyond calcium and phosphorus homeostasis. With this review, we aimed to summarize the changes in Vitamin D levels in children with cardiovascular diseases based on the literature. In addition, we also reviewed the potential mechanisms underlying cardiovascular diseases associated with Vitamin D deficiency or insufficiency. Data Sources： The articles in English were searched from PubMed （1968-2016） and EMBASE （1991-2016）, with the keywords of＂Vitamin D AND cardiovascular diseases＂ and ＂Vitamin D AND children.＂Study Selection： Original articles and critical reviews about Vitamin D and cardiovascular risk in children were selected for review. Researches focused on adults were excluded. Results： Studies have shown that several pediatric cardiovascular diseases may be associated with Vitamin D deficiency or insufficiency, including hypertension, orthostatic intolerance, and Kawasaki disease. Conclusions： Vitamin D may play a role in the regulation of the cardiovascular system. Further investigation would hopefully disclose the usefulness of Vitamin D as a biomarker for cardiovascular diseases in children.展开更多
Background： Vasovagal syncope （VVS） is the most common cause of syncope in children. Neuropeptide Y （NPY） plays an important role in the regulation of blood pressure （BP）, as well as myocardial contractility. T...Background： Vasovagal syncope （VVS） is the most common cause of syncope in children. Neuropeptide Y （NPY） plays an important role in the regulation of blood pressure （BP）, as well as myocardial contractility. This study aimed to explore the role of plasma NPY in VVS in children. Methods： Fifty-six children who were diagnosed with VVS （VVS group） using head-up tilt test （HUT） and 31 healthy children who were selected as controls （control group） were enrolled. Plasma NPY concentrations were detected. The independent t-test was used to compare the data of the VVS group with those of the control group. The changes in plasma NPY levels in the VVS group during the HUT, as well as hemodynamic parameters, such as heart rate （HR）, BP, total peripheral vascular resistance （TPVR）, and cardiac output （CO）, were evaluated using the paired t-test. Furthermore, the correlations between plasma NPY levels and hemodynamic parameters were analyzed using bivariate correlation analysis. Results： The BP, HR, and plasma NPY （0.34 ± 0.12 pg/ml vs. 0.46 ± 0.13 pg/ml） levels in the supine position were statistically low in the VVS group compared to levels in the control group （all P 〈 0.05）. Plasma NPY levels were positively correlated with the HR （Pearson, R = 0.395, P 〈 0.001） and diastolic BP （Pearson, R = 0.311, P = 0.003） when patients were in the supine position. When patients in the VVS group were in the supine position, elevated TPVR （4.6 ± 3.7 mmHg·min-1·L-1 vs. 2.5 ± 1.0 mmHg·min-1·L-1, respectively, P 〈 0.001;1 mmHg = 0.133 kPa） and reduced CO （1.0 ± 0.7 L/min vs. 2.4 ± 1.3 L/min, respectively, P 〈 0.001） were observed in the positive-response period compared with baseline values. The plasma NPY levels were positively correlated with TPVR （Spearman, R = 0.294, P = 0.028） but negatively correlated with CO in the positive-response period during HUT （Spearman, R = -0.318, P = 0.017）. Conclusions： Plasma NPY may contribute to the pathogene展开更多
When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered...When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered, earth-fixed (ECEF) co- ordinate, and attitude angles could be obtained through the rotation matrix between the body frame (BF) and the local level frame (LLF). Different from the conventional methods, a hybrid algorithm is presented to resolve attitude parameters utilizing the single differencing (SD) carrier phase equations established in LLF. Assuming that the cycle integer ambiguity is known, the measure- ment equations have attitude analytical resolutions by using simultaneous single difference equations for two in-view satellites. In addition, the algorithm is capable of reducing the search integer space into countable 2D discrete points and the ambiguity function method (AFM) resolves the ambiguity function within the analytical solutions space. In the case of frequency division multiple access (FDMA) for the Russian Global Orbiting Navigation Satellite System (GLONASS), a receiver clock bias estimation is employed to evaluate its carrier phase. An evaluating variable and a weighted factor are introduced to assess the integer ambiguity initialization. By static and dynamic ground experiments, the results show that the proposed approach is effective, with enough accuracy and low computation. It can satisfy attitude determination in cases of GPS alone and combined with GLONASS.展开更多
为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm...为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm^(-2),设置3种施肥量水平,低肥料(low fertility,LF)、中肥料(medium fertility,MF)和高肥料(high fertility,HF)分别为450 kg hm^(-2)、525 kg hm^(-2)和675 kg hm^(-2)进行大田试验。结果表明:中密中肥(medium density and medium fertilizer,MDMF)处理的产量最高,与低密高肥(low density and high fertilizer,LDHF)相比,MDMF处理的产量2年平均增幅3.15%,显著增加了有效穗数,稳定了其他产量因素,但收获指数增幅不高,甚至降低。齐穗期前高密高肥(high density and high fertilizer,HDHF)处理的地上部干物质量最高,2年平均增幅0.17%,齐穗后MDMF处理的地上部干物质量最高,2年平均增幅0.16%。MDMF处理在各生育时期的叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD)与LDHF处理相差不大,但MDMF处理的SPAD衰减率和LAI衰减率维持在较高水平,2021年和2022年MDMF处理条件下水稻SPAD衰减率分别为12.65%和16.85%,LAI衰减率分别为6.42%和6.74%。随着移栽密度和肥料的增加水稻分蘖数增加。由以上可知,适当的增密减肥可增加有效穗数,构造较高的群体结构和地上部干物质量,增加齐穗期至成熟期籼型杂交稻群体光合物质的生产及转运能力,保持了源的稳定,增加了产量库容量而获得高产,籼型杂交稻生产上宜采用栽插密度为22万株hm^(-2)和施肥量为525 kg hm^(-2)的组合。展开更多
Objective： Postural tachycardia syndrome （POTS） is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS i...Objective： Postural tachycardia syndrome （POTS） is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS in children. Data Sources： The data analyzed in this review are mainly from articles included in PubMed and EMBASE. Study Selection： The original articles and critical reviews about POTS were selected for this review. Results： Studies have shown that POTS might be related to several factors including hypovolemia, high catecholamine status, abnormal local vascular tension, and decreased skeletal muscle pump activity. In addition to exercise training, the first-line treatments mainly include oral rehydration salts, beta-adrenoreceptor blockers, and alpha-adrenoreceptor agonists. However, reports about the effectiveness of various treatments are diverse. By analyzing the patient＇s physiological indexes and biomarkers before the treatment, the efficacy of medication could be well predicted. Conclusions： The pathogenesis of POTS is multifactorial, including hypovolemia, abnormal catecholamine state, and vascular dysfunction. Biomarker-directed individualized treatment is an important strategy for the management of POTS children.展开更多
In children and adolescents,syncope is common and accounts for a considerable proportion of emergency visits.The underlying diseases of pediatric syncope mainly include neurally mediated syncope(NMS)and cardiogenic co...In children and adolescents,syncope is common and accounts for a considerable proportion of emergency visits.The underlying diseases of pediatric syncope mainly include neurally mediated syncope(NMS)and cardiogenic conditions.NMS accounts for 70–80%of pediatric syncopal cases,and one of the most common forms is vasovagal syncope(VVS)[1–3].In children with VVS,owing to the impairment of the barorefex integrity,the sympathetic system usually becomes overexcited after the change in position,leading to forceful contractions of a relatively empty ventricle and fnally causing a sympathetic withdrawal and an increased vagal activity.A relatively insufcient central volume,excessive vasodilation of peripheral vessel,autonomic nervous dysfunction,and neurohormonal disturbance may be aggravating factors.However,the efectiveness of previously unselected treatments for VVS has not been satisfactory.As such,a comprehensive assessment of the clinical characteristics,pathogenesis,and biochemical markers is needed to select the corresponding therapy.Since individualized treatment for VVS was proposed,several improvements have been made in the feld.展开更多
文摘Objective： Vitamin D is a group of fat-soluble molecules that are structurally similar to steroids. Emerging data have led to the hypothesis that Vitamin D plays a role in the regulation of many physiological processes beyond calcium and phosphorus homeostasis. With this review, we aimed to summarize the changes in Vitamin D levels in children with cardiovascular diseases based on the literature. In addition, we also reviewed the potential mechanisms underlying cardiovascular diseases associated with Vitamin D deficiency or insufficiency. Data Sources： The articles in English were searched from PubMed （1968-2016） and EMBASE （1991-2016）, with the keywords of＂Vitamin D AND cardiovascular diseases＂ and ＂Vitamin D AND children.＂Study Selection： Original articles and critical reviews about Vitamin D and cardiovascular risk in children were selected for review. Researches focused on adults were excluded. Results： Studies have shown that several pediatric cardiovascular diseases may be associated with Vitamin D deficiency or insufficiency, including hypertension, orthostatic intolerance, and Kawasaki disease. Conclusions： Vitamin D may play a role in the regulation of the cardiovascular system. Further investigation would hopefully disclose the usefulness of Vitamin D as a biomarker for cardiovascular diseases in children.
文摘Background： Vasovagal syncope （VVS） is the most common cause of syncope in children. Neuropeptide Y （NPY） plays an important role in the regulation of blood pressure （BP）, as well as myocardial contractility. This study aimed to explore the role of plasma NPY in VVS in children. Methods： Fifty-six children who were diagnosed with VVS （VVS group） using head-up tilt test （HUT） and 31 healthy children who were selected as controls （control group） were enrolled. Plasma NPY concentrations were detected. The independent t-test was used to compare the data of the VVS group with those of the control group. The changes in plasma NPY levels in the VVS group during the HUT, as well as hemodynamic parameters, such as heart rate （HR）, BP, total peripheral vascular resistance （TPVR）, and cardiac output （CO）, were evaluated using the paired t-test. Furthermore, the correlations between plasma NPY levels and hemodynamic parameters were analyzed using bivariate correlation analysis. Results： The BP, HR, and plasma NPY （0.34 ± 0.12 pg/ml vs. 0.46 ± 0.13 pg/ml） levels in the supine position were statistically low in the VVS group compared to levels in the control group （all P 〈 0.05）. Plasma NPY levels were positively correlated with the HR （Pearson, R = 0.395, P 〈 0.001） and diastolic BP （Pearson, R = 0.311, P = 0.003） when patients were in the supine position. When patients in the VVS group were in the supine position, elevated TPVR （4.6 ± 3.7 mmHg·min-1·L-1 vs. 2.5 ± 1.0 mmHg·min-1·L-1, respectively, P 〈 0.001;1 mmHg = 0.133 kPa） and reduced CO （1.0 ± 0.7 L/min vs. 2.4 ± 1.3 L/min, respectively, P 〈 0.001） were observed in the positive-response period compared with baseline values. The plasma NPY levels were positively correlated with TPVR （Spearman, R = 0.294, P = 0.028） but negatively correlated with CO in the positive-response period during HUT （Spearman, R = -0.318, P = 0.017）. Conclusions： Plasma NPY may contribute to the pathogene
文摘When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered, earth-fixed (ECEF) co- ordinate, and attitude angles could be obtained through the rotation matrix between the body frame (BF) and the local level frame (LLF). Different from the conventional methods, a hybrid algorithm is presented to resolve attitude parameters utilizing the single differencing (SD) carrier phase equations established in LLF. Assuming that the cycle integer ambiguity is known, the measure- ment equations have attitude analytical resolutions by using simultaneous single difference equations for two in-view satellites. In addition, the algorithm is capable of reducing the search integer space into countable 2D discrete points and the ambiguity function method (AFM) resolves the ambiguity function within the analytical solutions space. In the case of frequency division multiple access (FDMA) for the Russian Global Orbiting Navigation Satellite System (GLONASS), a receiver clock bias estimation is employed to evaluate its carrier phase. An evaluating variable and a weighted factor are introduced to assess the integer ambiguity initialization. By static and dynamic ground experiments, the results show that the proposed approach is effective, with enough accuracy and low computation. It can satisfy attitude determination in cases of GPS alone and combined with GLONASS.
基金supported by Fund Program for “Sanjin Scholars” of Shanxi ProvinceShanxi Province Science Foundation for Excellent Young Scholars (No.201801D211005)+3 种基金Research Project supported by Shanxi Scholarship Council of China (No.2020-083)the National Natural Science Foundation of China (No.31700918)Fund for Shanxi “1331 Project” Key Subjects Construction (No.1331KSC)Fund for Shanxi Key Subjects Construction (FSKSC)。
文摘为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm^(-2),设置3种施肥量水平,低肥料(low fertility,LF)、中肥料(medium fertility,MF)和高肥料(high fertility,HF)分别为450 kg hm^(-2)、525 kg hm^(-2)和675 kg hm^(-2)进行大田试验。结果表明:中密中肥(medium density and medium fertilizer,MDMF)处理的产量最高,与低密高肥(low density and high fertilizer,LDHF)相比,MDMF处理的产量2年平均增幅3.15%,显著增加了有效穗数,稳定了其他产量因素,但收获指数增幅不高,甚至降低。齐穗期前高密高肥(high density and high fertilizer,HDHF)处理的地上部干物质量最高,2年平均增幅0.17%,齐穗后MDMF处理的地上部干物质量最高,2年平均增幅0.16%。MDMF处理在各生育时期的叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD)与LDHF处理相差不大,但MDMF处理的SPAD衰减率和LAI衰减率维持在较高水平,2021年和2022年MDMF处理条件下水稻SPAD衰减率分别为12.65%和16.85%,LAI衰减率分别为6.42%和6.74%。随着移栽密度和肥料的增加水稻分蘖数增加。由以上可知,适当的增密减肥可增加有效穗数,构造较高的群体结构和地上部干物质量,增加齐穗期至成熟期籼型杂交稻群体光合物质的生产及转运能力,保持了源的稳定,增加了产量库容量而获得高产,籼型杂交稻生产上宜采用栽插密度为22万株hm^(-2)和施肥量为525 kg hm^(-2)的组合。
文摘Objective： Postural tachycardia syndrome （POTS） is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS in children. Data Sources： The data analyzed in this review are mainly from articles included in PubMed and EMBASE. Study Selection： The original articles and critical reviews about POTS were selected for this review. Results： Studies have shown that POTS might be related to several factors including hypovolemia, high catecholamine status, abnormal local vascular tension, and decreased skeletal muscle pump activity. In addition to exercise training, the first-line treatments mainly include oral rehydration salts, beta-adrenoreceptor blockers, and alpha-adrenoreceptor agonists. However, reports about the effectiveness of various treatments are diverse. By analyzing the patient＇s physiological indexes and biomarkers before the treatment, the efficacy of medication could be well predicted. Conclusions： The pathogenesis of POTS is multifactorial, including hypovolemia, abnormal catecholamine state, and vascular dysfunction. Biomarker-directed individualized treatment is an important strategy for the management of POTS children.
基金Peking University Clinical Scientist Program(BJMU2019LCKXJ001)the Fundamental Research Funds for the Central Universities.
文摘In children and adolescents,syncope is common and accounts for a considerable proportion of emergency visits.The underlying diseases of pediatric syncope mainly include neurally mediated syncope(NMS)and cardiogenic conditions.NMS accounts for 70–80%of pediatric syncopal cases,and one of the most common forms is vasovagal syncope(VVS)[1–3].In children with VVS,owing to the impairment of the barorefex integrity,the sympathetic system usually becomes overexcited after the change in position,leading to forceful contractions of a relatively empty ventricle and fnally causing a sympathetic withdrawal and an increased vagal activity.A relatively insufcient central volume,excessive vasodilation of peripheral vessel,autonomic nervous dysfunction,and neurohormonal disturbance may be aggravating factors.However,the efectiveness of previously unselected treatments for VVS has not been satisfactory.As such,a comprehensive assessment of the clinical characteristics,pathogenesis,and biochemical markers is needed to select the corresponding therapy.Since individualized treatment for VVS was proposed,several improvements have been made in the feld.
