机械零件参数化特征造型技术研究及应用

论述了在MDT环境的特征造型和开发技术,阐明了用MFC、ARX及MCAD API实现机械零件参数化特征造型的程序设计方法和关键技术,并给出了应用实例.     

数据库建设第七部分：结直肠癌手术特征的标签与结构化（一）

目的对华西肠癌数据库(DACCA)中结直肠癌手术特征的构成、定义及解读进行阐述。方法采用文字描述的形式。结果在华西DACCA中,结直肠癌手术特征模块主要包括手术特色、手术术式、手术操作细节、手术难点及手术质量评价这五大部分。在本章节内容中首先对手术特征模块中的手术特色这一部分的内容进行了定义、标签与结构化、纠错与更新以及在对DACCA中的数据进行分析时如何使用这些特征进行了详细阐述。结论通过对目前华西DACCA中手术特征模块中总体内容的介绍以及其中的手术特色这一部分内容的详细描述及规范,为结直肠癌的规范化治疗提供了参考依据,同时为想做结直肠癌数据库建设的同行们提供经验。     

整形外科发展史

整形外科艺术具有古老的历史,其起源与面部畸形有关,特别是与鼻部切割后的再造有关,即与个体、个人容貌的恢复有关。人的容貌特征是由基因水平决定的,其中包括面部特征的变化：个人无限的面部表情、声音音质、姿势及其运动．以及精神心理表达复合体,这些特征组成了人类的特质。     

心血管病专科护士胜任特征模型的构建

目的构建心血管病专科护士胜任特征模型,为心血管病专科护士的选拔、培训、考核提供依据。方法采用Delphi法对35名心血管病护理专家和医学专家进行2轮问卷函询,建立心血管病专科护士胜任特征模型。结果专家函询的权威系数为0.87,2轮函询问卷回收率分别为94.29%、96.97%,胜任特征族和胜任特征的协调系数分别为0.33、0.28。确定出知识族、技能族、角色能力族、个人特质族、动机族和价值观族6项胜任特征族和29项胜任特征的胜任特征模型。结论构建的心血管病专科护士胜任特征模型,专家意见集中,研究结果可信度高。     

妊娠期妇女体质量自我管理的定性用户画像研究

目的 探究妊娠期妇女体质量自我管理特征及人群差异,为制定针对性干预措施提供参考。方法 采用目的抽样法选取15名孕产妇进行半结构式访谈,通过Colaizzi 7步法分析资料;基于自我管理理论,人工抽取妊娠期妇女体质量自我管理特征构建画像,采用词云与表格形式完成画像的可视化。结果 提取5个特征：基本特征、认知特征、行为特征、社会支持特征、心理调适特征;构建4类妊娠期妇女体质量自我管理的典型画像：自主自律型、无能为力型、放任无为型、盲目实践型。结论 妊娠期妇女体质量自我管理存在较大的群体差异性,可根据不同的用户画像群体特征,给予个性化、精准化的管理方案。     

内科临床护士胜任特征模型的构建

目的构建内科临床护士胜任特征模型,为分配和选拔具有内科胜任特征的临床护士提供参考。方法以人类服务工作者通用词典为蓝本,通过文献分析和专家问卷法,构建内科护士胜任特征词典。运用行为事件访谈法对24名内科临床护士(优秀组、一般组各12人)进行访谈,再对访谈文本进行编码。对两组的胜任特征进行统计分析得出鉴别性胜任特征和基准性胜任特征。结果编码共得到20个胜任特征,其编码归类一致性85.47%~100%,经筛选,专业知识和技能、人际了解与沟通、主动积极、冲击与影响、南丁格尔精神和培养他人(6项,基准性胜任特征)及患者服务导向、自信心、职业修养和成就导向(4项,鉴别性胜任特征)10项进入内科临床护士胜任特征模型。结论本模型构建过程严谨,可为选拔、分配内科临床护士提供参考。下一步将编制内科临床护士胜任特征测评工具,使评选量化。     

甲状腺透明变梁状肿瘤诊治进展

正甲状腺透明变梁状肿瘤(hyalinizing trabecular tumor,HTT)是一种临床罕见的甲状腺原发性肿瘤,以包裹性结节、明显小梁状生长和基质透明样变为特征。Rahel于1905年最初报道此病,直到1987年Carney等才首次命名并详细描述了HTT的组织学特征,之后遂引起了甲状腺外科医师及病理学家的广泛关注。由于HTT的细胞学特征与甲状腺乳头状癌(papillary thyroid carcinoma,PTC)和甲状腺     

664例小儿烧伤流行病学统计分析

临床上小儿烧伤较为常见。许多年以前曾就小儿烧伤的原因、特征等作过较系统的流行病学研究［１］，但随着社会的发展和进步，小儿烧伤的特征也有了新的变化。我们就上海长海医院烧伤中心近７年来收治的６６４例烧伤小儿的发病率、致伤原因、病情特征等作了统计分析，旨在了解小儿烧伤的流行病学特征，以防止小儿烧伤的发生。１　资料和方法１９９１年１月至１９９７年７月期间收治的烧伤住院病人２８５８例，其中小儿烧伤（０～１２岁）６６４例。将致伤原因分为热水、热液、火焰、化学及电烧伤５种。烧伤程度分为轻度：＜５％ＴＢＳＡ，Ⅲ…     

三阴性乳腺癌超声影像组学定量特征分析

分析三阴性乳腺癌超声影像组学定量特征同临床表现、病理特征和免疫组织化学特征之间的联系.选择2013年6月—2019年6月在深圳市龙华区中心医院进行三阴性乳腺癌治疗的66例患者,均实施超声检查,回顾性分析超声检查结果与临床表现、病理特征及免疫组织化学特征[雌激素受体(ER)、人表皮生长因子受体-2(HER-2)、孕激素受...     

MRI影像组学特征联合临床特征鉴别布鲁杆菌性脊柱炎和化脓性脊柱炎

目的探讨临床特征及MRI T2加权脂肪抑制像(T2WI-FS)影像组学特征在布鲁杆菌性脊柱炎与化脓性脊柱炎鉴别诊断中的应用价值。方法收集2019年1月至2021年12月新疆医科大学附属第一医院经病理或病原学培养确诊的26例布鲁杆菌性脊柱炎和23例化脓性脊柱炎患者的临床资料。对人口学特征、临床特征及实验室检查等行单因素分析, 筛选出有统计学意义的潜在临床危险因素。通过手动勾画术前矢状面T2WI-FS的感兴趣区, 利用Pyradiomics包提取多样化的影像组学特征, 包括形状、纹理和灰度值等;对影像组学特征进行归一化、冗余性分析排除高度相关的特征, 再通过统计方法筛选与研究目标相关的特征;采用最小绝对收缩和选择算子(least absolute shrinkage and selection operator, LASSO)回归, 从高维特征中筛选出最具鉴别意义的特征以优化模型的预测性能;利用选出的影像组学特征计算影像组学评分。将筛选的临床危险因素、影像组学特征及影像组学评分纳入logistic回归, 构建临床特征模型、影像组学评分模型及临床特征-影像组学评分模型。采用混淆矩阵及受试者操...     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.