局部药代动力学的药物浓度时空方程初探

目的 建立局部植入给药的药物浓度时空方程。方法 将局部药物浓度时空方程构建为空间分布函数和时间分布函数(药物浓度经时方程)的积函数。并以加权平均及多元分析的数学手段予以证明及推导。结果 四维时空的局部植入给药的药物浓度时空方程的通式为：C(t，X，Y，Z)＝F(X，Y，Z)．C(t)，F(X，Y，Z)＝B0 B1X B2Y B3Z B4r3 B5r2 B6r,C(t)＝A1e^-Ket A2e^-Ket A3c^-Ket.。两维变量的简化的药物浓度时空方程为：C(t,ρ)＝F(ρ)．C(t)F(ρ)＝D0 D1ρ D2ρ2 D3ρ3，C(t)同上。结论 推导基本合理，并在初步的动物试验探索中得以验证。理论有较好科研价值，有助于揭示局部给药的药代动力学规律。     

氧化苦参碱胃内滞留缓释片的研制

目的：为延长苦参素的作用时间，降低肠道菌群的降解作用，便于给药，制成苦参素胃内滞留缓释片。方法：以HPMC为骨架材料，十六醇为助漂剂，碱式碳酸镁为产气剂，制备了一天给药两次的胃内滞留型缓释片，并进行体外累积释放度测定。结果：体外释药符合Higuchi方程，r=0．9864，体外释药量与释药时间具有良好的相关性，3个取样点及累积释放百分率分别为：1h20％。45％、2h35％～60％、8h75％以上，且起漂时间不超过5min。结论：该缓释片处方工艺简单，适合工业化生产；缓释效果明显。     

两种维生素C测定方法的比较

目的 :研究 2 ,6 -二氯酚靛酚法与 2 ,4 -二硝基苯肼法测定蔬菜和水果及尿液中抗坏血酸含量之间的关系。方法 :对蔬菜和水果样品 ,及扬州医学院大学生和市某幼儿园儿童 3h尿总量 ,收集前受试者排空小便后 ,口服 5 0 0 m g维生素C片剂 ,饮水 4 0 0 ml。分别用上述两种方法进行测定样品中维生素 C。结果 :在冬瓜和黄瓜中 ,两种方法所测维生素 C结果差异无统计学意义 ,而在黄豆芽和绿豆芽中 ,两种方法测定结果差异有统计学意义。对于尿样中的维生素 C,2 ,6 -二氯酚靛酚法所测定结果明显高于 2 ,4 -二硝基苯肼法 ,两者有明显的相关关系 ,其回归方程为 Y=- 14 .5 7 0 .5 2 9X。结论 :当用 2 ,6 -二氯酚靛酚法测定绿豆和黄豆芽中的维生素 C时 ,其误差较大。但对于尿中维生素 C,如果使用 2 ,6 -二氯酚靛酚法 ,则须用回归方程进行推断     

开封地区单纯性肥胖儿童心脏体积预测研究

【目的】　了解单纯肥胖儿童心脏体积及其放大率K值与正常体重儿童的差异 ,建立三种预测肥胖儿童心脏体积的回归方程。　【方法】　比较肥胖儿童心脏体积及其放大率K值与正常儿童的差异。经回归分析建立预测心脏深径法、体重法、胸径法预计肥胖儿童心脏体积的回归方程 ,并进行三种方法精确性比较。　【结果】　肥胖儿童心脏体积显著地大于正常体重儿童 ;中、重度肥胖心脏体积大于轻度肥胖者 ;心脏体积放大系数K值显著地小于正常体重儿童 (P <0 .0 1)。建立了预测心脏深径法方程、体重法方程、胸径法方程。　【结论】　用X线评价肥胖儿童心脏大小必须使用其自身数值和计算方程。     

结构方程模型及其应用

目的探讨结构方程模型方法,并运用该方法分析医学领域培训效果的影响因素.方法应用结构方程模型对培训效果领域的数据进行拟合,建立相应的测量模型与结构模型,通过参数估计揭示出变量之间的关系;而后进行参数的合理性检验与模型的显著性检验.结果采用结构方程模型方法,拟合了医学成人教育领域培训效果的数据.结构模型决定系数为0.60,意味着结构模型解释了因变量变异的60%.拟合优度指数GFI=0.909,调整的拟合优度指数AGFI=0.891以及其他指标,表明运用结构方程模型,较好地拟合了数据,合理解释了影响培训效果的因素.结论模型提示,培训效果可以用工作技能、工作适应性的提高以及考核成绩来进行表述,而影响培训效果的因素则表现为行医资历、培训形式、专业与服务人口总量、培训需求和教育程度.     

UV法及Weibull模型评价复方法莫替丁分散片的溶出特性

目的 :评价复方法莫替丁分散片在不同测定方法下的溶出特性。方法 :采用转篮法及桨法测定复方法莫替丁分散片的体外溶出度 ,溶液吸收度以紫外分光光度法测定 ;实验数据采用Excel软件 ,以Weibull分布模型求算溶出参数并拟合回归直线 ,用t检验进行统计学分析。结果 :采用转篮法及桨法测定本复方法莫替丁分散片的溶出度 ,其td 值分别为 1 30 6 3及 0 7931min ;直线斜率间存在统计学差异 (P <0 0 1)。结论 :本品溶出过程受测定方法影响较大 ,提示本品的体内溶出过程与胃肠运动密切相关。     

广州市六所中学初中男生吸烟行为影响因素的结构方程模型

目的 分析广州市青少年吸烟行为影响因素的直接与间接作用。方法 利用自填式问卷调查2021名初中男生的吸烟相关信息，确证性因子分析构建测量模型，迭代加权虽小二乘法（ERLS法）估计参数，通过评价修正来确定最佳模型。结果 提取了三个环境因素潜变量，即监护人限制、吸烟环境和学校环境。吸烟相关态度只提取一个潜变量。模型拟合效果较好，模型能解释吸烟行为38馆％的变异。对吸烟行为起直接作用的有：吸烟环境、监护人限制、拒烟决心和吸烟态度等。年级、健康知识和学校环境则起间接作用。危险因素排序：吸烟环境（45．76％）〉吸烟态度（19．88％）〉年级（0．44％）；保护因素排序：拒烟决心（16.61％）〉监护人限制（10．51％）〉健康知识（3．89％）〉学校环境（2．92％）。结论 健康知识只能通过相关信念而对学生吸烟行为起间接的抑制作用，且贡献比例很低。年级的增长对学生吸烟行为的促进作用大于抑制作用。青少年控烟不能只限于健康教育，环境因素应受到高度重视。     

不同厂家生产的盐酸曲马多缓释片整片与半片的三维释放特性考察

目的:对不同厂家(A、B、C)的盐酸曲马多缓释片的整片与半片进行pH-时间-释放度考察,探讨整片与半片体外释放机制的差异.方法:转篮法,用紫外分光光度法检测,描绘其三维释放图像,将释放数据用相似因子法、Peppas方程进行分析.结果:在同一pH条件下,A、C的整片与半片释放曲线不相似,释放机制也不相同;B的整片与半片释放曲线相似,释放机制相同.结论:不同厂家盐酸曲马多缓释片整片与半片的体外释放不尽相同.     

A comprehensive non‐invasive framework for automated evaluation of acute renal transplant rejection using DCE‐MRI

The objective was to develop a novel and automated comprehensive framework for the non‐invasive identification and classification of kidney non‐rejection and acute rejection transplants using 2D dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI). The proposed approach consists of four steps. First, kidney objects are segmented from the surrounding structures with a geometric deformable model. Second, a non‐rigid registration approach is employed to account for any local kidney deformation. In the third step, the cortex of the kidney is extracted in order to determine dynamic agent delivery, since it is the cortex that is primarily affected by the perfusion deficits that underlie the pathophysiology of acute rejection. Finally, we use an analytical function‐based model to fit the dynamic contrast agent kinetic curves in order to determine possible rejection candidates. Five features that map the data from the original data space to the feature space are chosen with a k‐nearest‐neighbor (KNN) classifier to distinguish between acute rejection and non‐rejection transplants. Our study includes 50 transplant patients divided into two groups: 27 patients with stable kidney function and the remainder with impaired kidney function. All of the patients underwent DCE‐MRI, while the patients in the impaired group also underwent ultrasound‐guided fine needle biopsy. We extracted the kidney objects and the renal cortex from DCE‐MRI for accurate medical evaluation with an accuracy of 0.97 ± 0.02 and 0.90 ± 0.03, respectively, using the Dice similarity metric. In a cohort of 50 participants, our framework classified all cases correctly (100%) as rejection or non‐rejection transplant candidates, which is comparable to the gold standard of biopsy but without the associated deleterious side‐effects. Both the 95% confidence interval (CI) statistic and the receiver operating characteristic (ROC) analysis document the ability to separate rejection and non‐rejection groups. The average plateau (AP) signal magnitude and the gamma‐variate model functional parameter α have the best individual discriminating characteristics. Copyright © 2013 John Wiley & Sons, Ltd.     

Two Nonlinear Positivity-Preserving Finite Volume Schemes for Three-Dimensional Heat Conduction Equations on General Polyhedral Meshes

In this article we present two types of nonlinear positivity-preserving finite volume (PPFV) schemes for a class of three-dimensional heat conduction equations on general polyhedral meshes. First, we present a new parameter selection strategy on the one-sided flux and establish a nonlinear PPFV scheme based on a two-point flux with higher efficiency. By comparing with the scheme proposed in [H. Xie, X. Xu, C. Zhai, H. Yong, Commun. Comput. Phys. 24 (2018) 1375–1408], our scheme avoids the assumption that the values of auxiliary unknowns are nonnegative, which makes our interpolation formulae suitable to be constructed by existing approaches with high accuracy and well robustness (e.g., the finite element method), thus enhancing the adaptability to distorted meshes with large deformations. Then we derive a linear multi-point flux involving combination coefficients and, via the Patankar trick, obtain another nonlinear PPFV scheme that is concise and easy to implement. The selection strategy of combination coefficients is also provided to improve the convergence behavior of the Picard procedure. Furthermore, the existence and positivity-preserving properties of these two nonlinear PPFV solutions are proved. Numerical experiments with the discontinuous diffusion scalar as well as discontinuous and anisotropic diffusion tensors are given to confirm our theoretical findings and demonstrate that our schemes both can achieve ideal-order accuracy even on severely distorted meshes.