BACKGROUND Neuropathy is a common complication of diabetes mellitus resulting from direct damage by hyperglycemia to the nerves and/or ischemia by microvascular injury to the endoneurial vessels which supply the nerve...BACKGROUND Neuropathy is a common complication of diabetes mellitus resulting from direct damage by hyperglycemia to the nerves and/or ischemia by microvascular injury to the endoneurial vessels which supply the nerves. Median nerve is one of the peripheral nerves commonly affected in diabetic neuropathy. The median nerve size has been studied in non-Nigerian diabetic populations. In attempt to contribute to existing literature, a study in a Nigerian population is needed.AIM To evaluate the cross-sectional area(CSA) of the median nerve using B-mode ultrasonography(USS) and the presence of peripheral neuropathy(PN) in a cohort of adult diabetic Nigerians.METHODS Demographic and anthropometric data of 85 adult diabetes mellitus(DM) and 85 age-and sex-matched apparently healthy control(HC) subjects were taken. A complete physical examination was performed on all study subjects to determine the presence of PN and modified Michigan Neuropathy Screening Instrument(MNSI) was used to grade its severity. Venous blood was taken from the study subjects for fasting lipid profile(FLP), fasting blood glucose(FBG) and glycated haemoglobin(HbA1 c) while their MN CSA was evaluated at a point 5 cm proximal to(5 cmCATL) and at the carpal tunnel(CATL) by high-resolution Bmode USS. Data was analysed using SPSS version 22.RESULTS The mean MN CSA was significantly thicker in DM subjects compared to the HC at 5 cmCATL(P < 0.01) and at the CATL(P < 0.01) on both sides. The presence of diabetic peripheral neuropathy(DPN) further increased the MN CSA at the CATL(P < 0.05) but not at 5 cmCATL(P > 0.05). However, the severity of DPN had no additional effect on MN CSA 5 cm proximal to and at the CATL. There was no significant association between MN CSA and duration of DM and glycemic control.CONCLUSION Thickening of the MN CSA at 5 cmCATL and CATL is seen in DM. Presence of DPN is associated with worse thickening of the MN CSA at the CATL but not at5 cmCATL. Severity of DPN, duration of DM, and glycemic control had no additional effect on the MN CSA.展开更多
High-resolution ultrasonography was used to analyze the nerve cross-sectional area （CSA） of the median nerve at 7 sites： the wrist crease, pisiform bone, hamate bone, 6 cm proximal to the tip of the wrist crease, p...High-resolution ultrasonography was used to analyze the nerve cross-sectional area （CSA） of the median nerve at 7 sites： the wrist crease, pisiform bone, hamate bone, 6 cm proximal to the tip of the wrist crease, proximal forearm （where the nerve enters the pronator teres muscle）, 4 cm proximal to the tip of the medial epicondyle, and mid-humerus （mid-point between elbow crease and axilla） in 200 healthy volunteers from Guiyang, China. Results showed similar CSA values between the left and right sides, but the CSA 6 cm proximal to the tip of the wrist crease, proximal forearm, 4 cm proximal to tip of the medial epicondyle, and mid-humerus in males was greater than that of females. Moreover, CSA values at the wrist crease, pisiform bone, and hamate bone were greater in the middle-aged and old groups when compared to the young group, and correlated with body mass and height. Thus, reference values of median nerve CSA of the upper limbs can facilitate the analysis of abnormal nerve conditions.展开更多
Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome r...Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome remains controversial. The cross-sectional areas of the median nerve at the tunnel inlet and outlet can show swelling and compression of the nerve at the carpal. We hypothesized that the ratio of the cross-sectional areas of the median nerve at the carpal tunnel inlet to outlet accurately reflects the severity of carpal tunnel syndrome. To test this, high-resolution ultrasound with a linear array transducer at 5–17 MHz was used to assess 77 patients with carpal tunnel syndrome. The results showed that the cut-off point for the inlet-to-outlet ratio was 1.14. Significant differences in the inlet-to-outlet ratio were found among patients with mild, moderate, and severe carpal tunnel syndrome. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.29 between mild and more severe（moderate and severe） carpal tunnel syndrome patients with 64.7% sensitivity and 72.7% specificity. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.52 between the moderate and severe carpal tunnel syndrome patients with 80.0% sensitivity and 64.7% specificity. These results suggest that the inlet-to-outlet ratio reflected the severity of carpal tunnel syndrome.展开更多
BACKGROUND Acromioclavicular joint(ACJ)space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis(ACJO).However,the morphology of the ACJ space is irregular because of oste...BACKGROUND Acromioclavicular joint(ACJ)space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis(ACJO).However,the morphology of the ACJ space is irregular because of osteophyte formation,subchondral irregularity,capsular distention,sclerosis,and erosion.Therefore,we created the ACJ cross-sectional area(ACJCSA)as a new diagnostic image parameter to assess the irregular morphologic changes of the ACJ.AIM To hypothesize that the ACJCSA is a new diagnostic image parameter for ACJO.METHODS ACJ samples were obtained from 35 patients with ACJO and 30 healthy individuals who underwent shoulder magnetic resonance(S-MR)imaging that revealed no evidence of ACJO.Oblique coronal,T2-weighted,fat-suppressed SMR images were acquired at the ACJ level from the two groups.We measured the ACJCSA and the ACJ space width(ACJSW)at the ACJ on the S-MR images using our imaging analysis program.The ACJCSA was measured as the cross-sectional area of the ACJ.The ACJSW was measured as the narrowest point between the acromion and the clavicle.RESULTS The average ACJCSA was 39.88±10.60 mm;in the normal group and 18.80±5.13 mm;in the ACJO group.The mean ACJSW was 3.51±0.58 mm in the normal group and 2.02±0.48 mm in the ACJO group.ACJO individuals had significantly lower ACJCSA and ACJSW than the healthy individuals.Receiver operating characteristic curve analyses demonstrated that the most suitable ACJCSA cutoff score was 26.14 mm^(2),with 91.4%sensitivity and 90.0%specificity.CONCLUSION The optimal ACJSW cutoff score was 2.37 mm,with 88.6%sensitivity and 96.7%specificity.Even though both the ACJCSA and ACJSW were significantly associated with ACJO,the ACJCSA was a more sensitive diagnostic image parameter.展开更多
Electroslag casting with parallel fixed-movable dual electrodes is a new method for achieving better quality of castings in complex mold cavities.In this work,a mathematical model,y=kx^2+(k+1)x,was established to desc...Electroslag casting with parallel fixed-movable dual electrodes is a new method for achieving better quality of castings in complex mold cavities.In this work,a mathematical model,y=kx^2+(k+1)x,was established to describe the ideal correlation between the current ratio(y)and the cross-sectional area ratio(x)of the dual electrodes,where k is the filling ratio.Investigation was conducted on the electroslag casting process with dual electrodes of various cross-sectional areas,but at a constant k value.The experimental results indicated that the ideal correlation was obtained at the stable casting stage,and the fitting results were consistent with the experimental results at certain k values.The experimental findings show that better castings can be obtained when the current ratio is greater than 1.536 and the cross-sectional area ratio is greater than 0.5.展开更多
地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理...地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理学者“可持续”研究的核心力量、重点区域与重要领域进行文献计量分析,结果表明:1)中国地理学者“可持续”研究的过程可分为快速兴起(1994—2001年)、稳定发展(2002—2011年)和整固深化(2012—2021年)三个阶段.2)中国开展“可持续”研究的地理学者多达624位,主要是自然地理学者和人文地理学者,研究机构多达258个,主要是中国科学院所属地理单位,机构间合作具有空间邻近性,机构空间分布具有东、中、西梯度分异性;中国地理学者“可持续”研究的对象区域以地方行政区域为主,服务国家重大区域发展战略的特色鲜明.3)中国地理学者“可持续”研究的重点领域有资源可持续利用、生态环境保护与建设、农业可持续发展、旅游可持续发展、可持续发展教育、可持续发展伦理、消除贫困与可持续生计、区域人地关系协调、城市可持续发展、农村可持续发展、区域可持续发展战略、区域可持续发展评价等.4)未来中国地理学者的“可持续”研究应在可持续发展专业人才培养、可持续发展理论体系完善、可持续发展研究领域拓展、可持续发展服务能力提升等方面下功夫.展开更多
This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The ...This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.展开更多
文摘BACKGROUND Neuropathy is a common complication of diabetes mellitus resulting from direct damage by hyperglycemia to the nerves and/or ischemia by microvascular injury to the endoneurial vessels which supply the nerves. Median nerve is one of the peripheral nerves commonly affected in diabetic neuropathy. The median nerve size has been studied in non-Nigerian diabetic populations. In attempt to contribute to existing literature, a study in a Nigerian population is needed.AIM To evaluate the cross-sectional area(CSA) of the median nerve using B-mode ultrasonography(USS) and the presence of peripheral neuropathy(PN) in a cohort of adult diabetic Nigerians.METHODS Demographic and anthropometric data of 85 adult diabetes mellitus(DM) and 85 age-and sex-matched apparently healthy control(HC) subjects were taken. A complete physical examination was performed on all study subjects to determine the presence of PN and modified Michigan Neuropathy Screening Instrument(MNSI) was used to grade its severity. Venous blood was taken from the study subjects for fasting lipid profile(FLP), fasting blood glucose(FBG) and glycated haemoglobin(HbA1 c) while their MN CSA was evaluated at a point 5 cm proximal to(5 cmCATL) and at the carpal tunnel(CATL) by high-resolution Bmode USS. Data was analysed using SPSS version 22.RESULTS The mean MN CSA was significantly thicker in DM subjects compared to the HC at 5 cmCATL(P < 0.01) and at the CATL(P < 0.01) on both sides. The presence of diabetic peripheral neuropathy(DPN) further increased the MN CSA at the CATL(P < 0.05) but not at 5 cmCATL(P > 0.05). However, the severity of DPN had no additional effect on MN CSA 5 cm proximal to and at the CATL. There was no significant association between MN CSA and duration of DM and glycemic control.CONCLUSION Thickening of the MN CSA at 5 cmCATL and CATL is seen in DM. Presence of DPN is associated with worse thickening of the MN CSA at the CATL but not at5 cmCATL. Severity of DPN, duration of DM, and glycemic control had no additional effect on the MN CSA.
基金the Science and Technology Foundation Program of Guizhou Province,No. J[2009]2157
文摘High-resolution ultrasonography was used to analyze the nerve cross-sectional area （CSA） of the median nerve at 7 sites： the wrist crease, pisiform bone, hamate bone, 6 cm proximal to the tip of the wrist crease, proximal forearm （where the nerve enters the pronator teres muscle）, 4 cm proximal to the tip of the medial epicondyle, and mid-humerus （mid-point between elbow crease and axilla） in 200 healthy volunteers from Guiyang, China. Results showed similar CSA values between the left and right sides, but the CSA 6 cm proximal to the tip of the wrist crease, proximal forearm, 4 cm proximal to tip of the medial epicondyle, and mid-humerus in males was greater than that of females. Moreover, CSA values at the wrist crease, pisiform bone, and hamate bone were greater in the middle-aged and old groups when compared to the young group, and correlated with body mass and height. Thus, reference values of median nerve CSA of the upper limbs can facilitate the analysis of abnormal nerve conditions.
基金supported by a grant from the Shanghai Key Laboratory of Peripheral Nerve and Microsurgery in China,No.14DZ2273300the Natural Science Foundation of Shanghai in China,No.13ZR1404600a grant from the National Key Basic Research Program of China(973 Program),No.2014CB542201
文摘Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome remains controversial. The cross-sectional areas of the median nerve at the tunnel inlet and outlet can show swelling and compression of the nerve at the carpal. We hypothesized that the ratio of the cross-sectional areas of the median nerve at the carpal tunnel inlet to outlet accurately reflects the severity of carpal tunnel syndrome. To test this, high-resolution ultrasound with a linear array transducer at 5–17 MHz was used to assess 77 patients with carpal tunnel syndrome. The results showed that the cut-off point for the inlet-to-outlet ratio was 1.14. Significant differences in the inlet-to-outlet ratio were found among patients with mild, moderate, and severe carpal tunnel syndrome. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.29 between mild and more severe（moderate and severe） carpal tunnel syndrome patients with 64.7% sensitivity and 72.7% specificity. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.52 between the moderate and severe carpal tunnel syndrome patients with 80.0% sensitivity and 64.7% specificity. These results suggest that the inlet-to-outlet ratio reflected the severity of carpal tunnel syndrome.
文摘BACKGROUND Acromioclavicular joint(ACJ)space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis(ACJO).However,the morphology of the ACJ space is irregular because of osteophyte formation,subchondral irregularity,capsular distention,sclerosis,and erosion.Therefore,we created the ACJ cross-sectional area(ACJCSA)as a new diagnostic image parameter to assess the irregular morphologic changes of the ACJ.AIM To hypothesize that the ACJCSA is a new diagnostic image parameter for ACJO.METHODS ACJ samples were obtained from 35 patients with ACJO and 30 healthy individuals who underwent shoulder magnetic resonance(S-MR)imaging that revealed no evidence of ACJO.Oblique coronal,T2-weighted,fat-suppressed SMR images were acquired at the ACJ level from the two groups.We measured the ACJCSA and the ACJ space width(ACJSW)at the ACJ on the S-MR images using our imaging analysis program.The ACJCSA was measured as the cross-sectional area of the ACJ.The ACJSW was measured as the narrowest point between the acromion and the clavicle.RESULTS The average ACJCSA was 39.88±10.60 mm;in the normal group and 18.80±5.13 mm;in the ACJO group.The mean ACJSW was 3.51±0.58 mm in the normal group and 2.02±0.48 mm in the ACJO group.ACJO individuals had significantly lower ACJCSA and ACJSW than the healthy individuals.Receiver operating characteristic curve analyses demonstrated that the most suitable ACJCSA cutoff score was 26.14 mm^(2),with 91.4%sensitivity and 90.0%specificity.CONCLUSION The optimal ACJSW cutoff score was 2.37 mm,with 88.6%sensitivity and 96.7%specificity.Even though both the ACJCSA and ACJSW were significantly associated with ACJO,the ACJCSA was a more sensitive diagnostic image parameter.
文摘Electroslag casting with parallel fixed-movable dual electrodes is a new method for achieving better quality of castings in complex mold cavities.In this work,a mathematical model,y=kx^2+(k+1)x,was established to describe the ideal correlation between the current ratio(y)and the cross-sectional area ratio(x)of the dual electrodes,where k is the filling ratio.Investigation was conducted on the electroslag casting process with dual electrodes of various cross-sectional areas,but at a constant k value.The experimental results indicated that the ideal correlation was obtained at the stable casting stage,and the fitting results were consistent with the experimental results at certain k values.The experimental findings show that better castings can be obtained when the current ratio is greater than 1.536 and the cross-sectional area ratio is greater than 0.5.
文摘地理学研究可持续发展旨在构建人与自然命运共同体,实现人类社会的永续发展.该文依托CNKI数据库、读秀资源库以及Web of Science数据库,限定主题词为“可持续”“可持续发展”和“可持续性”,采用CiteSpace软件对1994—2021年中国地理学者“可持续”研究的核心力量、重点区域与重要领域进行文献计量分析,结果表明:1)中国地理学者“可持续”研究的过程可分为快速兴起(1994—2001年)、稳定发展(2002—2011年)和整固深化(2012—2021年)三个阶段.2)中国开展“可持续”研究的地理学者多达624位,主要是自然地理学者和人文地理学者,研究机构多达258个,主要是中国科学院所属地理单位,机构间合作具有空间邻近性,机构空间分布具有东、中、西梯度分异性;中国地理学者“可持续”研究的对象区域以地方行政区域为主,服务国家重大区域发展战略的特色鲜明.3)中国地理学者“可持续”研究的重点领域有资源可持续利用、生态环境保护与建设、农业可持续发展、旅游可持续发展、可持续发展教育、可持续发展伦理、消除贫困与可持续生计、区域人地关系协调、城市可持续发展、农村可持续发展、区域可持续发展战略、区域可持续发展评价等.4)未来中国地理学者的“可持续”研究应在可持续发展专业人才培养、可持续发展理论体系完善、可持续发展研究领域拓展、可持续发展服务能力提升等方面下功夫.
文摘This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.
