A pseudoplastic metal nanoparticle fluid (PMNF) is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key ...A pseudoplastic metal nanoparticle fluid (PMNF) is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.展开更多
Objective To analyze the causes and prevention and treatment of cerebrospinal fluid leak during transsphenoidal pituitary adenoma surgery. Methods Retrospective study of 260 cases of microscopic transsphenoidal surger...Objective To analyze the causes and prevention and treatment of cerebrospinal fluid leak during transsphenoidal pituitary adenoma surgery. Methods Retrospective study of 260 cases of microscopic transsphenoidal surgery and 274 cases of endoscopic surgery for resection of the pituitary adenomas was performed. CSF leak occurred展开更多
The type, size, and compositions of fluid inclusions in a natural sphalerite were investigated and the total concentration of Zn released from the fluid inclusions was measured. To compare the total concentration of Z...The type, size, and compositions of fluid inclusions in a natural sphalerite were investigated and the total concentration of Zn released from the fluid inclusions was measured. To compare the total concentration of Zn released from the fluid inclusions with that dissolved from the sphalerite itself, dissolution experiments and theoretical calculations for the dissolution equilibrium of the sphalerite were also performed. The results indicate that large numbers of fluid inclusions with various sizes exist in the sphalerite, which can be divided into four types, i.e., pure gaseous inclusions, pure liquid inclusions, gas-liquid inclusions, and gas-liquid inclusions containing solid minerals. These inclusions were broken open during the grinding process, and their compositions were released to the solution. The total concentration of Zn released from these inclusions reaches 18.35×10^-6 mol/L, which is much higher than that of Zn dissolved from the sphalerite itself (1.93×10^-6 mol/L) and the theoretical calculation value (2.73×10^-8 mol/L).展开更多
In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the hor...In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber,so that it is difficult to experimentally measure the temperature of the transducer and its variation with time,which bring heavy difficulty to the design of the ultrasonic molten metal treatment system.To find a way out,conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method.In modeling of the system,the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation.Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution.Numerical results show that,after about 350 s of working time,temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling.At 240 s,The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2,while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2,which indicates the effectiveness of heat insulation of the asbestos pad.Transient heat transfer film coefficient and its distribution,which are difficult to be measured experimentally are also obtained through numerical simulation.At 240 s,the heat transfer film coefficient in the surface of the transducer ranges from–17.86 to 20.17 W/(m2?K).Compared with the trial and error method based on the test,the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.展开更多
Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clini...Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clinical practice, one minimally invasive surgical procedure is the implantation of a metallic stent to cover the aneurysm neck. This flow diverting device can reduce the flow into the aneurysm and enhance the prospect of thrombosis, a condition expected to reduce the risk of growth and rupture. The biomechanical and haemo-dynamic factors in stented and nonstented situations are studied by computational fluid dynamics. Unlike earlier models with straight or curved parent blood vessels, the aneurysm is now located near an arterial bifurcation. The influence of the aspect (depth to neck) ratio of the aneurysm on the flow dynamics will be emphasized, especially in the post-operation stages. More precisely, the maximum flow velocity, the variations of wall shear stress, the risk of stent migration and volumetric flow rate after endovascular treatment will be studied. Aneurysms with larger aspect ratios (i.e. smaller neck sizes for constant depth) generally pose a greater risk in terms of these flow parameters. These results will assist the applications and design of stents in future neurosurgical therapy. The approach is limited to a nonelastic model, without taking into account of questions like stent expansion and interaction with tissue.展开更多
Intracranial aneurysm occurs when a cerebral artery develops an abnormal sac-like dilatation, and will cause massive bleeding in the subarachnoid space upon rupture. Endovascular stenting is a minimally invasive proce...Intracranial aneurysm occurs when a cerebral artery develops an abnormal sac-like dilatation, and will cause massive bleeding in the subarachnoid space upon rupture. Endovascular stenting is a minimally invasive procedure in which a flow-diverting stent is deployed to cover the aneurysm neck, thereby restricting blood from entering the aneurysm and reducing the risk of rupture. The stent porosity, a crucial factor determining the intra-aneurysmal hemodynamics following treatment, is investigated by computational fluid dynamics techniques. Based on the computational results, a low porosity stent will dramatically reduce the flow velocity and the flow rate inside the side branch vessel. Conversely, a high porosity stent may not provide adequate flow reduction inside the aneurysm, possibly causing treatment failure. An advisable range of optimal stent porosity would be 60% to 75%, which can drastically reduce the flow rate into the aneurysm while preserving enough blood flow for the side branch vessel. Clinically, deployment of two or more flow-diverting stents may not increase treatment efficacy but can potentially lead to adverse effects due to side-branch hypoperfusion. The present quantitative analysis can also provide practical insight for future stent design.展开更多
Pancreatic fluid collections(PFCs),common sequelae of acute or chronic pancreatitis,are broadly classified as pancreatic pseudocysts or walled-off necrosis according to the revised Atlanta classification.Endoscopic ul...Pancreatic fluid collections(PFCs),common sequelae of acute or chronic pancreatitis,are broadly classified as pancreatic pseudocysts or walled-off necrosis according to the revised Atlanta classification.Endoscopic ultrasound(EUS)-guided drainage is often considered a standard first-line therapy preferable to surgical or interventional radiology approaches for patients with symptomatic PFC.EUS-guided drainage is effective and successful;it has a technical success rate of90%-100%and a clinical success rate of 85%-98%.Recent studies have shown a 5%-30%adverse events(AEs)rate for the procedure.The most common AEs include infection,hemorrhage,perforation and stent migration.Hemorrhage,a severe and sometimes deadly outcome,requires a well-organized and appropriate treatment strategy.However,few studies have reported the integrated management of hemorrhage during EUS-guided drainage of PFC.Establishing a practical therapeutic strategy is an essential and significant step in standardized management.The aim of this review is to describe the current situation of EUS-guided drainage of PFCs,including the etiology and treatment of procedure-related bleeding as well as current problems and future perspectives.We propose a novel and meaningful algorithm for systematically managing hemorrhage events.To our limited knowledge,a multidisciplinary algorithm for managing EUS-guided drainage for PFC-related bleeding has not been previously reported.展开更多
目的探究不同液体复苏方法治疗严重骨盆骨折失血性休克的效果及预后分析。方法前瞻性选取2021年6月—2023年6月笔者医院收治的严重骨盆骨折失血性休克患者96例为研究对象,其中男性56例,女性40例;年龄18~55岁,平均38.6岁;道路交通伤51例...目的探究不同液体复苏方法治疗严重骨盆骨折失血性休克的效果及预后分析。方法前瞻性选取2021年6月—2023年6月笔者医院收治的严重骨盆骨折失血性休克患者96例为研究对象,其中男性56例,女性40例;年龄18~55岁,平均38.6岁;道路交通伤51例,高处坠落伤24例,挤压伤21例。患者入院后均完成止血、骨折外固定等外科急救处理,常规监测生命体征、建立静脉通道、完善血常规等术前检查。随机数字表法分为研究组48例与对照组48例。对照组患者进行常规快速液体复苏,及时补充足量的平衡液、胶体液、悬浮红细胞、血浆等,研究组予以限制性液体复苏,前期适当输入高渗氯化钠溶液,而后输入平衡液等。比较两组入院时、复苏后3 d生命体征指标,凝血指标与急性生理与慢性健康II(APACHEⅡ)评分,电解质水平以及入院时、复苏后30 min、1 h炎症因子水平,观察两组预后指标差异。结果两组复苏后3 d全心舒张末期容量指数(GEDVI)、心脏指数(CI)、心排血量(CO)、氧合指数(PaO_(2)/FiO_(2))、MAP、中心静脉压(CVP)与入院时比较均升高,血乳酸(LAC)、HR与入院时比较均降低(P<0.05);且研究组复苏后3 d上述生命体征指标改变幅度优于对照组(P<0.05)。两组复苏后3 d TT、PT、APTT与入院时比较均升高,APACHEⅡ评分与入院时比较均降低(P<0.05);且研究组复苏后3 d TT、PT、APTT、APACHEⅡ评分均低于对照组(P<0.05)。两组复苏后3 d Na+与入院时比较均升高,K+与入院时比较均降低(P<0.05);但两组复苏后3 d Cl^(-)、Mg^(2+)、Na^(+)、K^(+)比较差异无统计学意义(P>0.05)。重复测量方差分析结果显示,两组y干扰素(y-IFN)、IL-4、IL-6、TNF-α的时点、组间、交互效应比较差异有统计学意义(P<0.05),两组复苏后30 min、1 h的y-IFN、IL-4、IL-6、TNF-α与入院时相比均显著升高,且复苏后1 h的y-IFN、IL-4、IL-6、TNF-α高于复苏后30 min(P<0.05),但研究组复苏后30 min、1 h的y-IFN、IL-4、IL-6、TNF-α均低于对照组(P<0.05)。两组急性呼吸窘迫综合征、弥散性血管内凝血、多器官功能障碍综合征、急性肾衰竭、肺部感染、腹腔感染发生率比较差异无统计学意义(P>0.05),但研究组并发症总发生率与病死率均低于对照组(8.3%vs.37.5%,2.1%vs.16.7%,P<0.05)。结论限制性急诊液体复苏方法治疗严重骨盆骨折失血性休克具有较好应用效果,可有效改善患者生命体征,纠正凝血功能紊乱状态,减轻炎症反应,降低并发症发生风险,改善预后。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 51175479 and 51475436the Education Department of Henan Province under Grant Nos 13A460725 and 2013GGJS-001
文摘A pseudoplastic metal nanoparticle fluid (PMNF) is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.
文摘Objective To analyze the causes and prevention and treatment of cerebrospinal fluid leak during transsphenoidal pituitary adenoma surgery. Methods Retrospective study of 260 cases of microscopic transsphenoidal surgery and 274 cases of endoscopic surgery for resection of the pituitary adenomas was performed. CSF leak occurred
基金supported by the Key Program of the National Natural Science Foundation of China(No.u0837602)the Analysis Testing Foundation of Kunming University of Science and Technology(No.2010-303)
文摘The type, size, and compositions of fluid inclusions in a natural sphalerite were investigated and the total concentration of Zn released from the fluid inclusions was measured. To compare the total concentration of Zn released from the fluid inclusions with that dissolved from the sphalerite itself, dissolution experiments and theoretical calculations for the dissolution equilibrium of the sphalerite were also performed. The results indicate that large numbers of fluid inclusions with various sizes exist in the sphalerite, which can be divided into four types, i.e., pure gaseous inclusions, pure liquid inclusions, gas-liquid inclusions, and gas-liquid inclusions containing solid minerals. These inclusions were broken open during the grinding process, and their compositions were released to the solution. The total concentration of Zn released from these inclusions reaches 18.35×10^-6 mol/L, which is much higher than that of Zn dissolved from the sphalerite itself (1.93×10^-6 mol/L) and the theoretical calculation value (2.73×10^-8 mol/L).
基金Supported by Beijing Municipal Natural Science Foundation of China(Grant No.3093027)
文摘In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber,so that it is difficult to experimentally measure the temperature of the transducer and its variation with time,which bring heavy difficulty to the design of the ultrasonic molten metal treatment system.To find a way out,conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method.In modeling of the system,the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation.Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution.Numerical results show that,after about 350 s of working time,temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling.At 240 s,The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2,while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2,which indicates the effectiveness of heat insulation of the asbestos pad.Transient heat transfer film coefficient and its distribution,which are difficult to be measured experimentally are also obtained through numerical simulation.At 240 s,the heat transfer film coefficient in the surface of the transducer ranges from–17.86 to 20.17 W/(m2?K).Compared with the trial and error method based on the test,the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.
文摘Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clinical practice, one minimally invasive surgical procedure is the implantation of a metallic stent to cover the aneurysm neck. This flow diverting device can reduce the flow into the aneurysm and enhance the prospect of thrombosis, a condition expected to reduce the risk of growth and rupture. The biomechanical and haemo-dynamic factors in stented and nonstented situations are studied by computational fluid dynamics. Unlike earlier models with straight or curved parent blood vessels, the aneurysm is now located near an arterial bifurcation. The influence of the aspect (depth to neck) ratio of the aneurysm on the flow dynamics will be emphasized, especially in the post-operation stages. More precisely, the maximum flow velocity, the variations of wall shear stress, the risk of stent migration and volumetric flow rate after endovascular treatment will be studied. Aneurysms with larger aspect ratios (i.e. smaller neck sizes for constant depth) generally pose a greater risk in terms of these flow parameters. These results will assist the applications and design of stents in future neurosurgical therapy. The approach is limited to a nonelastic model, without taking into account of questions like stent expansion and interaction with tissue.
文摘Intracranial aneurysm occurs when a cerebral artery develops an abnormal sac-like dilatation, and will cause massive bleeding in the subarachnoid space upon rupture. Endovascular stenting is a minimally invasive procedure in which a flow-diverting stent is deployed to cover the aneurysm neck, thereby restricting blood from entering the aneurysm and reducing the risk of rupture. The stent porosity, a crucial factor determining the intra-aneurysmal hemodynamics following treatment, is investigated by computational fluid dynamics techniques. Based on the computational results, a low porosity stent will dramatically reduce the flow velocity and the flow rate inside the side branch vessel. Conversely, a high porosity stent may not provide adequate flow reduction inside the aneurysm, possibly causing treatment failure. An advisable range of optimal stent porosity would be 60% to 75%, which can drastically reduce the flow rate into the aneurysm while preserving enough blood flow for the side branch vessel. Clinically, deployment of two or more flow-diverting stents may not increase treatment efficacy but can potentially lead to adverse effects due to side-branch hypoperfusion. The present quantitative analysis can also provide practical insight for future stent design.
文摘Pancreatic fluid collections(PFCs),common sequelae of acute or chronic pancreatitis,are broadly classified as pancreatic pseudocysts or walled-off necrosis according to the revised Atlanta classification.Endoscopic ultrasound(EUS)-guided drainage is often considered a standard first-line therapy preferable to surgical or interventional radiology approaches for patients with symptomatic PFC.EUS-guided drainage is effective and successful;it has a technical success rate of90%-100%and a clinical success rate of 85%-98%.Recent studies have shown a 5%-30%adverse events(AEs)rate for the procedure.The most common AEs include infection,hemorrhage,perforation and stent migration.Hemorrhage,a severe and sometimes deadly outcome,requires a well-organized and appropriate treatment strategy.However,few studies have reported the integrated management of hemorrhage during EUS-guided drainage of PFC.Establishing a practical therapeutic strategy is an essential and significant step in standardized management.The aim of this review is to describe the current situation of EUS-guided drainage of PFCs,including the etiology and treatment of procedure-related bleeding as well as current problems and future perspectives.We propose a novel and meaningful algorithm for systematically managing hemorrhage events.To our limited knowledge,a multidisciplinary algorithm for managing EUS-guided drainage for PFC-related bleeding has not been previously reported.
文摘目的探究不同液体复苏方法治疗严重骨盆骨折失血性休克的效果及预后分析。方法前瞻性选取2021年6月—2023年6月笔者医院收治的严重骨盆骨折失血性休克患者96例为研究对象,其中男性56例,女性40例;年龄18~55岁,平均38.6岁;道路交通伤51例,高处坠落伤24例,挤压伤21例。患者入院后均完成止血、骨折外固定等外科急救处理,常规监测生命体征、建立静脉通道、完善血常规等术前检查。随机数字表法分为研究组48例与对照组48例。对照组患者进行常规快速液体复苏,及时补充足量的平衡液、胶体液、悬浮红细胞、血浆等,研究组予以限制性液体复苏,前期适当输入高渗氯化钠溶液,而后输入平衡液等。比较两组入院时、复苏后3 d生命体征指标,凝血指标与急性生理与慢性健康II(APACHEⅡ)评分,电解质水平以及入院时、复苏后30 min、1 h炎症因子水平,观察两组预后指标差异。结果两组复苏后3 d全心舒张末期容量指数(GEDVI)、心脏指数(CI)、心排血量(CO)、氧合指数(PaO_(2)/FiO_(2))、MAP、中心静脉压(CVP)与入院时比较均升高,血乳酸(LAC)、HR与入院时比较均降低(P<0.05);且研究组复苏后3 d上述生命体征指标改变幅度优于对照组(P<0.05)。两组复苏后3 d TT、PT、APTT与入院时比较均升高,APACHEⅡ评分与入院时比较均降低(P<0.05);且研究组复苏后3 d TT、PT、APTT、APACHEⅡ评分均低于对照组(P<0.05)。两组复苏后3 d Na+与入院时比较均升高,K+与入院时比较均降低(P<0.05);但两组复苏后3 d Cl^(-)、Mg^(2+)、Na^(+)、K^(+)比较差异无统计学意义(P>0.05)。重复测量方差分析结果显示,两组y干扰素(y-IFN)、IL-4、IL-6、TNF-α的时点、组间、交互效应比较差异有统计学意义(P<0.05),两组复苏后30 min、1 h的y-IFN、IL-4、IL-6、TNF-α与入院时相比均显著升高,且复苏后1 h的y-IFN、IL-4、IL-6、TNF-α高于复苏后30 min(P<0.05),但研究组复苏后30 min、1 h的y-IFN、IL-4、IL-6、TNF-α均低于对照组(P<0.05)。两组急性呼吸窘迫综合征、弥散性血管内凝血、多器官功能障碍综合征、急性肾衰竭、肺部感染、腹腔感染发生率比较差异无统计学意义(P>0.05),但研究组并发症总发生率与病死率均低于对照组(8.3%vs.37.5%,2.1%vs.16.7%,P<0.05)。结论限制性急诊液体复苏方法治疗严重骨盆骨折失血性休克具有较好应用效果,可有效改善患者生命体征,纠正凝血功能紊乱状态,减轻炎症反应,降低并发症发生风险,改善预后。