In healthy subjects, the rate of acid reflux during transient lower esophageal sphincter relaxations (TLESRs) is more frequent at the proximal margin of the L ES. In this study, we investigated the hypothesis that the...In healthy subjects, the rate of acid reflux during transient lower esophageal sphincter relaxations (TLESRs) is more frequent at the proximal margin of the L ES. In this study, we investigated the hypothesis that the rate of acid reflux a t the proximal margin of LES during TLESRs is similar in reflux disease to that in healthy subjects. Concurrent esophageal manometry and pH monitoring were perf ormed in the sitting position for 3 hr after a standard meal in 10 patients with reflux disease and 10 agematched healthy controls. The rate of TLESRs in patien ts with reflux disease (5.0/hr [3.3-6.7]; median [interquartile range])-was si milar to that of controls (4.5/hr [3.7-5.7]). The incidence of acid reflux 7 cm above the LES during TLESRs in patients (48.1%[27.2-71.4%])was significantly higher than that in controls (10.9%[0.0-18.8%]) but there was no difference 2 cm above the LES (75.0 [69.2-87.5] vs. 74.3 [55.5-90.0%]). The rate of TLES Rs and the incidence of acid reflux during TLESRs are not increased in reflux disease. These findings, therefore, indicat e that reflux disease is not a disorder of TLESRs and relates more to the proxim al extent of the refluxate.展开更多
There is increasing evidence that obesity may damage the kidney in otherwise healthy individuals. Our study investigated the effect of childhood obesity on urinary albumin and beta-2-microglobulin excretion, and the a...There is increasing evidence that obesity may damage the kidney in otherwise healthy individuals. Our study investigated the effect of childhood obesity on urinary albumin and beta-2-microglobulin excretion, and the association of these with obesity-related cardiovascular risk factors. Random morning spot urine samples were collected fromclinically healthy obese (n = 86; median age 12.9 years, range 8.9-17.2 years; median weight 80.6 kg, range 46.1-136.8 kg; median body mass index 30.4 kg/m2, range 24.5-43.2 kg/m2) and normal weight children ( n = 79; median age 13.5 years, range 10.7-14.9 years; median weight 51.0 kg, range 27.3-72.5 kg; median body mass index 18.2 kg/m2, range 13.2-23.9 kg/m2). The obese children were examined for the presence of common obesity-related cardiovascular risk factors including hyperinsulinaemia, impaired glucose tolerance (IGT), dyslipidaemia, hypercholesterolaemia, and hypertension. Obese children had a significantly higher urinary albumin/creatinine ratio (U-ACR)-(median 11.7mg/g, interquartile range 12.9mg/g versusmedian 9.0 mg/g, interquartile range 5.1 mg/g; P = 0.003) and urinary beta-2-microglobulin/creatinine ratio (U-BMCR) (median 63.9 μg/g, interquartile range 34.7 μg/g versus median 34.6 μg/g, interquartile range 44.1 μg/g; P < 0.001) than normal weight children. Among the obese children, the U-ACR was associated with fasting hyperinsulinaemia, IGT, and hypercholesterolaemia (all P < 0.05), and significantly correlated with the fasting (r = 0.23, P < 0.05) and 2-h (r = 0.37, P < 0.001) plasma glucose levels measured during an oral glucose tolerance test. Obese children with no more than one of the features of the metabolic syndrome had significantly lower U-ACRs than obese children with two or more features (median 10.4 mg/g, interquartile range 5.8 mg/g versus median 15.3 mg/g, interquartile range 14.9 mg/g; P < 0.05). Conclusion: According to our results, clinically healthy obese children have a higher degree of albuminuria and beta-2-microglobulinuria than normal weight children, indicating early renal glomerular and tubular dysfunction as a consequence of childhood obesity. The urinary albumin/creatinine ratio in the obese children was associated with certain metabolic derangements linked to obesity, and also with the clustering of features of the metabolic syndrome.展开更多
Background: In endoscopic biliary stenting against malignant biliary obstruction, stent blockage remains as an important problem. Stent blockage occurs as a result of bacterial adherence to the inner wall of the stent...Background: In endoscopic biliary stenting against malignant biliary obstruction, stent blockage remains as an important problem. Stent blockage occurs as a result of bacterial adherence to the inner wall of the stent. We evaluated the stent placement above the intact sphincter of Oddi to retain the function of the sphincter of Oddi as a bacteriological barrier. Methods: Sixteen patients with malignant biliary obstruction were assessed as the patients with the stent above the intact sphincter of Oddi. Sixteen patients with malignant biliary obstruction were assessed as the patients with the conventional stent placement across the sphincter of Oddi. Tannenbaum 10 Fr. stents were used in both the groups. Results: The median patency periods of the stent were 255 days (25th to 75th percentiles, 212-454 days; range, 39-454 days) for the group of the stents placed above the sphincter of Oddi and 82 days (25th to 75th percentiles, 48-131 days; range, 22-196 days) for the group of the stents placed across the sphincter of Oddi, respectively, with significant difference (P = 0.0001). The occlusion rates of stents placed above and across the sphincter of Oddi were 37.5%and 93.8%, respectively, with significant difference (P = 0.0008). The dislocation rates of the stent were 0%and 6.3%, respectively (not significant). Conclusions: Placement of the stent above the intact sphincter of Oddi was associated with longer stent patency and lower occlusion rate.展开更多
Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate...Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate mucosal injury and mural weakness leading to bile duct dilatation, at normal intraduct pressures.However, bile duct pressures in both normal or disease states are not known in such children.Methods: Intraoperative choledochal pressure (CP) measurements were made before any other manipulation.Bile was cultured and its amylase content measured.Biochemical liver function (bilirubin, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase)was measured.Datawere quoted as median (interquartile range).Statistical tests were parametric, where appropriate, and P =.05 was regarded as significant.Results: Twenty-five children (age 2.5 [1.25-5.91] years) with choledochal (cystic [n = 13] and fusiform [n = 12]) malformation coming to surgery were studied.Median CP was 13 (8.5-17)-mm Hg.Median bile amylase was 6722 (241-18,000) IU/L.Choledochal pressure inversely correlated with bile amylase (r = -0.60, P =.001), serum aspartate aminotransferase (r = 0.46, P =.01), and log γ-glutamyl transpeptidase (r = 0.4, P =.04) but not with bilirubin (P =.11), alkaline phosphatase (P =.20), or age (P =.11).No difference in CP, bile amylase, or liver biochemistry could be identified between the 2 biliary phenotypes.All bile cultures were sterile.Conclusions: Increased CP is inversely related to the level of bile amylase (and hence degree of the functional common channel).This suggests that obstructive stenosis at the level of the pancreato-biliary junction (but not the ampulla) may be a causal factor in a proportion of choledochal malformations.展开更多
The management of an appendiceal mass remains controversial with 2 schools of thought; early surgical intervention vs nonoperative management with or without interval appendectomy. The aim is to determine the role and...The management of an appendiceal mass remains controversial with 2 schools of thought; early surgical intervention vs nonoperative management with or without interval appendectomy. The aim is to determine the role and safety of early laparoscopic appendectomy (LA) in children with acute appendicitis presenting with an appendiceal mass. Methods: This is a prospective study of 88 consecutive pediatric patients who underwent attempted LA for suspected acute appendicitis at KK Women’s and Children’s Hospital, Singapore, between May and October 2003. Results: A total of 88 patients with a mean age of 10 ± 3 years (range, 3- 16 years) underwent LA for an appendiceal mass (n = 22), simple appendicitis (n = 36), other complicated (gangrenous or perforated) appendicitis (n = 23), and a normal appendix (n = 7). There were 7 conversions to open appendicectomy, 3 of which occurred in patients with an appendiceal mass. There were no perioperative or postoperative mortalities. Morbidity occurred in only one patient who underwent LA for perforated appendicitis. He had prolonged sepsis that resolved after 2 weeks of intravenous antibiotics. None of the patients with an appendiceal mass developed complications. Patients who underwent early LA for an appendiceal mass had a statistically significant (P<.05) longer operating time (median, 103 minutes; interquartile range, 90- 151 minutes, vs median, 87 minutes; interquartile range, 71- 112 minutes), prolonged time to ambulation (median, 2.0 days; interquartile range, 2- 2.5 days, vs median, 1.0 days; interquartile, 1- 2 days), increased time to resumption of diet (median, 4 days; interquartile, 3- 5 days, vs median, 2 days; interquartile, 2- 3 days), and longer postoperative stay (median,6.0 days; interquartile, 5.5- 6.5 days, vs median, 4.0 days; interquartile, 3- 5.5 days) compared with patients presenting with appendicitis without mass formation. However, there was no statistical difference in these parameters when LA for an appendiceal mass was compared with LA for other complicated appendicitis (perforated and gangrenous). Conclusion: Although early LA for an appendiceal mass is a technically demanding procedure, it can be performed safely in children with minimal morbidity and mortality. In an era where patients’ demand for “ key-hole” surgery is rising, early LA is a safe and viable option in the management of children with an appendiceal mass. It also offers the advantage of avoiding misdiagnoses and the need for a second hospitalization.展开更多
BACKGROUND: Reversible left ventricular dysfunction precipitated by emotional stress has been reported, but the mechanism remains unknown. METHODS: We evaluated 19 patients who presented with left ventricular dysfunct...BACKGROUND: Reversible left ventricular dysfunction precipitated by emotional stress has been reported, but the mechanism remains unknown. METHODS: We evaluated 19 patients who presented with left ventricular dysfunction after sudden emotional stress. All patients underwent coronary angiography and serial echocardiography; five underwent endomyocardial biopsy. Plasma catecholamine levels in 13 patients with stress-related myocardial dysfunction were compared with those in 7 patients with Killip class III myocardial infarction. RESULTS: The median age of patients with stress-induced cardiomyopathy was 63 years, and 95 percent were women. Clinical presentations included chest pain, pulmonary edema, and cardiogenic shock. Diffuse T-wave inversion and a prolonged QT interval occurred in most patients. Seventeen patients had mildly elevated serum troponin I levels, but only 1 of 19 had angiographic evidence of clinically significant coronary disease. Severe left ventricular dysfunction was present on admission(median ejection fraction, 0.20; interquartile range, 0.15 to 0.30) and rapidly resolved in all patients(ejection fraction at two to four weeks, 0.60; interquartile range, 0.55 to 0.65; P< 0.001). Endomyocardial biopsy showed mononuclear infiltrates and contraction-band necrosis. Plasma catecholamine levels at presentation were markedly higher among patients with stress-induced cardiomyopathy than among those with Killip class III myocardial infarction(median epinephrine level, 1264 pg per milliliter[interquartile range, 916 to 1374] vs. 376 pg per milliliter[interquartile range, 275 to 476]; norepinephrine level, 2284 pg per milliliter[interquartile range, 1709 to 2910] vs. 1100 pg per milliliter[interquartile range, 914 to 1320]; and dopamine level, 111 pg per milliliter[interquartile range, 106 to 146] vs. 61 pg per milliliter[interquartile range, 46 to 77]; P< 0.005 for all comparisons). CONCLUSIONS: Emotional stress can precipitate severe, reversible left ventricular dysfunction in patients without coronary disease. Exaggerated sympathetic stimulation is probably central to the cause of this syndrome.展开更多
In this paper, we integrate inertial navigation system (INS) with wireless sensor network (WSN) to enhance the accuracy of indoor localization. Inertial measurement unit (IMU), the core of the INS, measures the accele...In this paper, we integrate inertial navigation system (INS) with wireless sensor network (WSN) to enhance the accuracy of indoor localization. Inertial measurement unit (IMU), the core of the INS, measures the accelerated and angular rotated speed of moving objects. Meanwhile, the ranges from the object to beacons, which are sensor nodes with known coordinates, are collected by time of arrival (ToA) approach. These messages are simultaneously collected and transmitted to the terminal. At the terminal, we set up the state transition models and observation models. According to them, several recursive Bayesian algorithms are applied to producing position estimations. As shown in the experiments, all of three algorithms do not require constant moving speed and perform better than standalone ToA system or standalone IMU system. And within them, two algorithms can be applied for the tracking on any path which is not restricted by the requirement that the trajectory between the positions at two consecutive time steps is a straight line.展开更多
This paper describes the influence of joint spacing and joint orientation on the penetration rate of a Tunnel Boring Machine （TBM） disc cutter as modeled by the Discrete Element Method （DEM）. The input data for th...This paper describes the influence of joint spacing and joint orientation on the penetration rate of a Tunnel Boring Machine （TBM） disc cutter as modeled by the Discrete Element Method （DEM）. The input data for the siLmulations were obtained from the sandstone along the AIborz tunnel that is currently being excavated in Iran using a 5.2 m diameter open TBM. Three joint spacings, 150, 200, and 300 mm, were modeled together with seven values of joint orientation; 0°, 15°, 30°, 45°, 60°, 75°, and 90°. The results show that the penetration increases when joint orientation increases from 0° to 75°, but it decreases as the joint orientation increases further from 75° to 90°. This is true for each joint spacing. In addition, for a given joint orientation increasing the joint spacing causes the TBM penetration to decrease. The optimum joint orientation, from the viewpoint of TBM penetration, is about 60-75°.展开更多
In the long distance GIL under certain conditions, this paper researches and realizes detection of PD characters and accurate fault localization through UHF coupling sensors at different positions of the GIL pipeline....In the long distance GIL under certain conditions, this paper researches and realizes detection of PD characters and accurate fault localization through UHF coupling sensors at different positions of the GIL pipeline. The main methods for the detection are UHF signal amplitude difference （DOA） and time difference （TOF）. We analyze the localization error by using TE and TEM component and high order TE mode component in electromagnetic coaxial wave guide theory. Research and field test prove the DOA detection error can meet the requirements of real-time online diagnosis and for history tracking analysis. The error of TOF detection method can be controlled within 3% and can be applied to the site.展开更多
通过磁共振成像评估的主动脉弓脉搏波传导速度（pulse wave velocity,PWV）对心血管病事件的预测价值尚未完全确定。为了评估多种族动脉粥样硬化研究（multi-ethnic study of atherosclerosis,MESA）受试者中主动脉弓PWV与心血管病的关...通过磁共振成像评估的主动脉弓脉搏波传导速度（pulse wave velocity,PWV）对心血管病事件的预测价值尚未完全确定。为了评估多种族动脉粥样硬化研究（multi-ethnic study of atherosclerosis,MESA）受试者中主动脉弓PWV与心血管病的关系,Ohyama等纳入3527例MESA受试者[基线时平均年龄为（62±10）岁,47%为男性],展开更多
文摘In healthy subjects, the rate of acid reflux during transient lower esophageal sphincter relaxations (TLESRs) is more frequent at the proximal margin of the L ES. In this study, we investigated the hypothesis that the rate of acid reflux a t the proximal margin of LES during TLESRs is similar in reflux disease to that in healthy subjects. Concurrent esophageal manometry and pH monitoring were perf ormed in the sitting position for 3 hr after a standard meal in 10 patients with reflux disease and 10 agematched healthy controls. The rate of TLESRs in patien ts with reflux disease (5.0/hr [3.3-6.7]; median [interquartile range])-was si milar to that of controls (4.5/hr [3.7-5.7]). The incidence of acid reflux 7 cm above the LES during TLESRs in patients (48.1%[27.2-71.4%])was significantly higher than that in controls (10.9%[0.0-18.8%]) but there was no difference 2 cm above the LES (75.0 [69.2-87.5] vs. 74.3 [55.5-90.0%]). The rate of TLES Rs and the incidence of acid reflux during TLESRs are not increased in reflux disease. These findings, therefore, indicat e that reflux disease is not a disorder of TLESRs and relates more to the proxim al extent of the refluxate.
文摘There is increasing evidence that obesity may damage the kidney in otherwise healthy individuals. Our study investigated the effect of childhood obesity on urinary albumin and beta-2-microglobulin excretion, and the association of these with obesity-related cardiovascular risk factors. Random morning spot urine samples were collected fromclinically healthy obese (n = 86; median age 12.9 years, range 8.9-17.2 years; median weight 80.6 kg, range 46.1-136.8 kg; median body mass index 30.4 kg/m2, range 24.5-43.2 kg/m2) and normal weight children ( n = 79; median age 13.5 years, range 10.7-14.9 years; median weight 51.0 kg, range 27.3-72.5 kg; median body mass index 18.2 kg/m2, range 13.2-23.9 kg/m2). The obese children were examined for the presence of common obesity-related cardiovascular risk factors including hyperinsulinaemia, impaired glucose tolerance (IGT), dyslipidaemia, hypercholesterolaemia, and hypertension. Obese children had a significantly higher urinary albumin/creatinine ratio (U-ACR)-(median 11.7mg/g, interquartile range 12.9mg/g versusmedian 9.0 mg/g, interquartile range 5.1 mg/g; P = 0.003) and urinary beta-2-microglobulin/creatinine ratio (U-BMCR) (median 63.9 μg/g, interquartile range 34.7 μg/g versus median 34.6 μg/g, interquartile range 44.1 μg/g; P < 0.001) than normal weight children. Among the obese children, the U-ACR was associated with fasting hyperinsulinaemia, IGT, and hypercholesterolaemia (all P < 0.05), and significantly correlated with the fasting (r = 0.23, P < 0.05) and 2-h (r = 0.37, P < 0.001) plasma glucose levels measured during an oral glucose tolerance test. Obese children with no more than one of the features of the metabolic syndrome had significantly lower U-ACRs than obese children with two or more features (median 10.4 mg/g, interquartile range 5.8 mg/g versus median 15.3 mg/g, interquartile range 14.9 mg/g; P < 0.05). Conclusion: According to our results, clinically healthy obese children have a higher degree of albuminuria and beta-2-microglobulinuria than normal weight children, indicating early renal glomerular and tubular dysfunction as a consequence of childhood obesity. The urinary albumin/creatinine ratio in the obese children was associated with certain metabolic derangements linked to obesity, and also with the clustering of features of the metabolic syndrome.
文摘Background: In endoscopic biliary stenting against malignant biliary obstruction, stent blockage remains as an important problem. Stent blockage occurs as a result of bacterial adherence to the inner wall of the stent. We evaluated the stent placement above the intact sphincter of Oddi to retain the function of the sphincter of Oddi as a bacteriological barrier. Methods: Sixteen patients with malignant biliary obstruction were assessed as the patients with the stent above the intact sphincter of Oddi. Sixteen patients with malignant biliary obstruction were assessed as the patients with the conventional stent placement across the sphincter of Oddi. Tannenbaum 10 Fr. stents were used in both the groups. Results: The median patency periods of the stent were 255 days (25th to 75th percentiles, 212-454 days; range, 39-454 days) for the group of the stents placed above the sphincter of Oddi and 82 days (25th to 75th percentiles, 48-131 days; range, 22-196 days) for the group of the stents placed across the sphincter of Oddi, respectively, with significant difference (P = 0.0001). The occlusion rates of stents placed above and across the sphincter of Oddi were 37.5%and 93.8%, respectively, with significant difference (P = 0.0008). The dislocation rates of the stent were 0%and 6.3%, respectively (not significant). Conclusions: Placement of the stent above the intact sphincter of Oddi was associated with longer stent patency and lower occlusion rate.
文摘Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate mucosal injury and mural weakness leading to bile duct dilatation, at normal intraduct pressures.However, bile duct pressures in both normal or disease states are not known in such children.Methods: Intraoperative choledochal pressure (CP) measurements were made before any other manipulation.Bile was cultured and its amylase content measured.Biochemical liver function (bilirubin, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase)was measured.Datawere quoted as median (interquartile range).Statistical tests were parametric, where appropriate, and P =.05 was regarded as significant.Results: Twenty-five children (age 2.5 [1.25-5.91] years) with choledochal (cystic [n = 13] and fusiform [n = 12]) malformation coming to surgery were studied.Median CP was 13 (8.5-17)-mm Hg.Median bile amylase was 6722 (241-18,000) IU/L.Choledochal pressure inversely correlated with bile amylase (r = -0.60, P =.001), serum aspartate aminotransferase (r = 0.46, P =.01), and log γ-glutamyl transpeptidase (r = 0.4, P =.04) but not with bilirubin (P =.11), alkaline phosphatase (P =.20), or age (P =.11).No difference in CP, bile amylase, or liver biochemistry could be identified between the 2 biliary phenotypes.All bile cultures were sterile.Conclusions: Increased CP is inversely related to the level of bile amylase (and hence degree of the functional common channel).This suggests that obstructive stenosis at the level of the pancreato-biliary junction (but not the ampulla) may be a causal factor in a proportion of choledochal malformations.
文摘The management of an appendiceal mass remains controversial with 2 schools of thought; early surgical intervention vs nonoperative management with or without interval appendectomy. The aim is to determine the role and safety of early laparoscopic appendectomy (LA) in children with acute appendicitis presenting with an appendiceal mass. Methods: This is a prospective study of 88 consecutive pediatric patients who underwent attempted LA for suspected acute appendicitis at KK Women’s and Children’s Hospital, Singapore, between May and October 2003. Results: A total of 88 patients with a mean age of 10 ± 3 years (range, 3- 16 years) underwent LA for an appendiceal mass (n = 22), simple appendicitis (n = 36), other complicated (gangrenous or perforated) appendicitis (n = 23), and a normal appendix (n = 7). There were 7 conversions to open appendicectomy, 3 of which occurred in patients with an appendiceal mass. There were no perioperative or postoperative mortalities. Morbidity occurred in only one patient who underwent LA for perforated appendicitis. He had prolonged sepsis that resolved after 2 weeks of intravenous antibiotics. None of the patients with an appendiceal mass developed complications. Patients who underwent early LA for an appendiceal mass had a statistically significant (P<.05) longer operating time (median, 103 minutes; interquartile range, 90- 151 minutes, vs median, 87 minutes; interquartile range, 71- 112 minutes), prolonged time to ambulation (median, 2.0 days; interquartile range, 2- 2.5 days, vs median, 1.0 days; interquartile, 1- 2 days), increased time to resumption of diet (median, 4 days; interquartile, 3- 5 days, vs median, 2 days; interquartile, 2- 3 days), and longer postoperative stay (median,6.0 days; interquartile, 5.5- 6.5 days, vs median, 4.0 days; interquartile, 3- 5.5 days) compared with patients presenting with appendicitis without mass formation. However, there was no statistical difference in these parameters when LA for an appendiceal mass was compared with LA for other complicated appendicitis (perforated and gangrenous). Conclusion: Although early LA for an appendiceal mass is a technically demanding procedure, it can be performed safely in children with minimal morbidity and mortality. In an era where patients’ demand for “ key-hole” surgery is rising, early LA is a safe and viable option in the management of children with an appendiceal mass. It also offers the advantage of avoiding misdiagnoses and the need for a second hospitalization.
文摘BACKGROUND: Reversible left ventricular dysfunction precipitated by emotional stress has been reported, but the mechanism remains unknown. METHODS: We evaluated 19 patients who presented with left ventricular dysfunction after sudden emotional stress. All patients underwent coronary angiography and serial echocardiography; five underwent endomyocardial biopsy. Plasma catecholamine levels in 13 patients with stress-related myocardial dysfunction were compared with those in 7 patients with Killip class III myocardial infarction. RESULTS: The median age of patients with stress-induced cardiomyopathy was 63 years, and 95 percent were women. Clinical presentations included chest pain, pulmonary edema, and cardiogenic shock. Diffuse T-wave inversion and a prolonged QT interval occurred in most patients. Seventeen patients had mildly elevated serum troponin I levels, but only 1 of 19 had angiographic evidence of clinically significant coronary disease. Severe left ventricular dysfunction was present on admission(median ejection fraction, 0.20; interquartile range, 0.15 to 0.30) and rapidly resolved in all patients(ejection fraction at two to four weeks, 0.60; interquartile range, 0.55 to 0.65; P< 0.001). Endomyocardial biopsy showed mononuclear infiltrates and contraction-band necrosis. Plasma catecholamine levels at presentation were markedly higher among patients with stress-induced cardiomyopathy than among those with Killip class III myocardial infarction(median epinephrine level, 1264 pg per milliliter[interquartile range, 916 to 1374] vs. 376 pg per milliliter[interquartile range, 275 to 476]; norepinephrine level, 2284 pg per milliliter[interquartile range, 1709 to 2910] vs. 1100 pg per milliliter[interquartile range, 914 to 1320]; and dopamine level, 111 pg per milliliter[interquartile range, 106 to 146] vs. 61 pg per milliliter[interquartile range, 46 to 77]; P< 0.005 for all comparisons). CONCLUSIONS: Emotional stress can precipitate severe, reversible left ventricular dysfunction in patients without coronary disease. Exaggerated sympathetic stimulation is probably central to the cause of this syndrome.
基金Project(61301181) supported by the National Natural Science Foundation of China
文摘In this paper, we integrate inertial navigation system (INS) with wireless sensor network (WSN) to enhance the accuracy of indoor localization. Inertial measurement unit (IMU), the core of the INS, measures the accelerated and angular rotated speed of moving objects. Meanwhile, the ranges from the object to beacons, which are sensor nodes with known coordinates, are collected by time of arrival (ToA) approach. These messages are simultaneously collected and transmitted to the terminal. At the terminal, we set up the state transition models and observation models. According to them, several recursive Bayesian algorithms are applied to producing position estimations. As shown in the experiments, all of three algorithms do not require constant moving speed and perform better than standalone ToA system or standalone IMU system. And within them, two algorithms can be applied for the tracking on any path which is not restricted by the requirement that the trajectory between the positions at two consecutive time steps is a straight line.
文摘This paper describes the influence of joint spacing and joint orientation on the penetration rate of a Tunnel Boring Machine （TBM） disc cutter as modeled by the Discrete Element Method （DEM）. The input data for the siLmulations were obtained from the sandstone along the AIborz tunnel that is currently being excavated in Iran using a 5.2 m diameter open TBM. Three joint spacings, 150, 200, and 300 mm, were modeled together with seven values of joint orientation; 0°, 15°, 30°, 45°, 60°, 75°, and 90°. The results show that the penetration increases when joint orientation increases from 0° to 75°, but it decreases as the joint orientation increases further from 75° to 90°. This is true for each joint spacing. In addition, for a given joint orientation increasing the joint spacing causes the TBM penetration to decrease. The optimum joint orientation, from the viewpoint of TBM penetration, is about 60-75°.
文摘In the long distance GIL under certain conditions, this paper researches and realizes detection of PD characters and accurate fault localization through UHF coupling sensors at different positions of the GIL pipeline. The main methods for the detection are UHF signal amplitude difference （DOA） and time difference （TOF）. We analyze the localization error by using TE and TEM component and high order TE mode component in electromagnetic coaxial wave guide theory. Research and field test prove the DOA detection error can meet the requirements of real-time online diagnosis and for history tracking analysis. The error of TOF detection method can be controlled within 3% and can be applied to the site.
文摘通过磁共振成像评估的主动脉弓脉搏波传导速度（pulse wave velocity,PWV）对心血管病事件的预测价值尚未完全确定。为了评估多种族动脉粥样硬化研究（multi-ethnic study of atherosclerosis,MESA）受试者中主动脉弓PWV与心血管病的关系,Ohyama等纳入3527例MESA受试者[基线时平均年龄为（62±10）岁,47%为男性],
