几何不确定性鲁棒优化在肝癌立体定向放疗中的应用

目的:分析基于几何不确定性的鲁棒优化计划对肝癌立体定向放疗（SBRT）剂量分布的影响。方法:选取12例肝癌SBRT患者，对每例制作3个调强计划:①基于PTV（ITV-PTV 5 mm）的常规优化（PTV-Based Plan）；②基于ITV非均匀几何不确定性（本中心计算的不确定性值:进出方向7 mm，左右和前后方向4 mm）的鲁棒优化（Robust Planactual）；③基于ITV均匀5 mm几何不确定性的鲁棒优化（Robust Plan5 mm）。所有计划都以95%的PTV满足处方剂量作为目标，以等中心均匀偏移4、5、7 mm计算扰动剂量评估鲁棒性。结果:计划①②③的均匀性指数（HI）分别为0.083±0.027、0.099±0.035、0.096±0.026，不具有统计学意义；计划①②③的适形性指数（CI）分别为0.98±0.02、1.02±0.05、1.00±0.04，计划②③相对于计划①的CI具有统计学意义。计划③的正常肝组织平均受量和V2500相对于计划①②分别下降了4.1%、2.5%和5.4%、3.0%，且具有统计学意义（P=0.034、P=0.021和P=0.004、P=0.004），计划②相对于计划①的正常肝组织平均受量和V2500不具有统计学意义（P=0.308和P=0.182），但下降了1.6%和2.5%。对于其鲁棒性，计划②③的5 mm-D99%、5 mm-D98%、5 mm-D95%的剂量-体积直方图带宽（DVHBW）差值相对于计划①更小，随着摆位不确定度的增大，其DVHBW差值越大。结论:在肝脏SBRT治疗中，采用鲁棒优化能够提高靶区剂量分布质量，即使在摆位不确定度有所增加的情况下，仍可以保证ITV的剂量覆盖同时不增加正常组织的照射剂量。     

优化早交班内涵的实践与成效

目的 探讨早交班内涵的优化与实践成效。方法 评估传统早交班内涵, 对传统早交接内涵进行优化、培训, 使责任护士掌握并应用于临床实践, 对优化前、后的早交班内涵的相关护理指标进行评价。结果 早交班内涵优化后的护理质量及患者对责任护士的满意度较优化前有显著提高, 差异有统计学意义(P<0.05)。结论 早交班内涵的优化提高了护理工作的质量及效率, 体现了优质护理的人性化、连续性、整体性、专业化。     

Linear quadratic regulator control of multi‐agent systems

This paper considers a collection of agents performing a shared task making use of relative information communicated over an information network. The designed suboptimal controllers are state feedback and static output feedback, which are guaranteed to provide a certain level of performance in terms of a linear quadratic regulator (LQR) cost. Because of the convexity of the LQR performance region, the suboptimal LQR control problem with state feedback is reduced to the solution of two inequalities, with the minimum and maximum eigenvalues of the Laplacian matrix as the coefficients. The advantage of the method is that the LQR control problem of network multi‐agent systems can be converted into the LQR control of a set of single‐agent systems, and the structure constraint on the feedback gain matrix can be eliminated. It can be shown that the size of the LQR control problem will not increase according to the number of the node in the fairly general framework. The method can be extended to the synthesis of the static output feedback, which is derived from the weighting matrices in LQR. Through some coordinate transformation and the augmentation of the output matrix, the LQR synthesis is provided on the basis of the output measurements of the adjacent agents. Numerical examples are presented to illustrate the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.     

Optimal spatial field control for controlled release

Most distributed parameter control problems involve manipulation within the spatial domain. Such problems arise in a variety of applications including epidemiology, tissue engineering, and cancer treatment. This paper proposes an approach to solve a state‐constrained spatial field control problem that is motivated by a biomedical application. In particular, the considered manipulation over a spatial field is described by partial differential equations (PDEs) with spatial frequency constraints. The proposed optimization algorithm for tracking a reference spatial field combines three‐dimensional Fourier series, which are truncated to satisfy the spatial frequency constraints, with exploitation of structural characteristics of the PDEs. The computational efficiency and performance of the optimization algorithm are demonstrated in a numerical example. In the example, the spatial tracking error is shown to be almost entirely due to the limitation on the spatial frequency of the manipulated field. The numerical results suggest that the proposed optimal control approach has promise for controlling the release of macromolecules in tissue engineering applications.     

The potential of three-dimensional printing technologies to unlock the development of new ‘bio-inspired’ dental materials: an overview and research roadmap

Purpose

Bio-inspiration is an approach in engineering aimed at optimizing artificial systems by borrowing biological concepts from nature. This review sets out to summarize the fundamental aspects employed by nature to avoid premature dental failures. On the basis of these findings, it then defines and evaluates rules for ‘post-modern’ manufacturing processes to imitate or regenerate complex biological systems.

二甲基姜黄素的合成工艺优化

摘 要 目的：对现有的二甲基姜黄素的合成路线进行工艺优化。方法：以乙酰丙酮作为起始原料,反应分两步进行,首先制得乙酰丙酮的硼络合物,然后与藜芦醛反应得到二甲基姜黄素,并对第二步的反应条件及后处理进行优化。结果：第二步反应制备二甲基姜黄素时,以N,N-二甲基乙酰胺（DMA）作为溶剂,反应温度为80℃,淬灭反应使用的酸用量为正丁胺的1.5当量,结晶补加水的体积为溶剂的2倍时,转化率最高。粗品收率95.1%,纯度98.6%,重结晶后总收率92.3%,纯度99.2%。结论：该路线原料廉价易得,反应条件温和,适合工业化生产。     

基于网站调研的智能医学工程专业设置和培养方案分析

目的　分析我国智能医学工程专业设置和培养方案的现状。方法　通过网站调研获取该专业的开设学校、开设年份、招生计划、培养目标和课程等信息。利用Excel进行统计分析。结果　①2018至2021年,共有48所高校被批准开设智能医学工程专业,以经济发达地区为主,人才培养规模为每年近2 400人。②获取47所高校智能医学工程专业的所属学院信息,其中59%（13/22）的综合性高校将该专业归属医学相关的学院。③获取40所高校的专业培养目标,重点培养学生具备大数据智能处理和软件研发能力,其中12所高校还要求学生掌握硬件研发能力。④计算机科学与技术、基础医学、临床医学和生物医学工程是该专业的主干学科,专业核心课程主要包括计算机语言和人工智能相关课程。结论　随着人工智能技术在医疗卫生领域的发展,我国智能医学工程专业教育快速兴起,但对专业人才的培养还处于探索阶段,建议国家有关部门出台相关指导性意见。     

经皮内镜下腰椎间盘切除术的日间手术(8 h内)诊疗流程的建立、优化及应用效果

目的探讨在日间手术模式下经皮穿刺内镜下腰椎椎间盘切除术(percutaneous endoscopic lumbar discectomy,PELD)治疗腰椎间盘突出症(lumbar disc hernation,LDH)管理流程的建立、优化及应用效果。 方法借鉴笔者所在医院已经开展的日间手术管理经验,根据前期PELD日间手术流程遇到的问题,对日间管理流程进行改进,制定PELD日间手术治疗LDH的管理制度和诊疗流程,改进工作规范,于2021年7月起应用PELD日间手术治疗患者100例,对全部患者进行最少30 d的随访,对诊疗流程应用前后患者的手术时间、伤口感染发生率、并发症发生率、爽约率、当日取消率、未准点开台率、入院前的等待时间、30 d内再入院率、延迟出院率及患者满意度共计十项评价指标分别采用t检验、卡方检验或Fisher精确检验等进行统计分析。 结果自2021年3~12月在日间病房共完成PELD的200例。其中2021年3~6月期间日间病房收治的100例PELD患者为对照组;自2021年7~12月期间日间病房共收治100例PELD患者作为观察组。比较发现两组患者在年龄、性别、手术节段、突出类型及手术入路等基本信息方面差异无统计学意义(P>0.05)。在经过日间手术管理流程建立和优化后,患者在入院前的等待时间、并发症发生率、爽约率及未准点开台率方面均明显下降;观察组的患者满意度明显高于对照组;而手术时间、伤口感染、当日取消率、30 d内再入院率、延迟出院率方面差异无统计学意义(P>0.05)。 结论PELD日间手术开展初期,可以借鉴传统日间手术的模式,建立适合本院医疗结构的PELD日间手术流程,笔者建立的改进措施能够降低患者手术前院外等待时间、降低爽约率、提高准点开台率等,可供相关医疗单位借鉴和应用。     

Concomitant Malnutrition and Frailty Are Uncommon,but Significant Risk Factors for Mortality and Complication Following Primary Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) demand continues to rise, but we are also gaining greater insight into patient risk factors for postoperative complications and excess resource utilization. There has been growing interest in frailty and malnutrition as risk factors, although they are often mistakenly used interchangeably. We aimed at identifying the incidence of their coexistence, and the magnitude of risk they confer to TKA patients.MethodsWe queried the American College of Surgeons-National Surgery Quality Improvement Program database to identify 4 patient cohorts: healthy/normal serum albumin, healthy/hypoalbuminemic patients, normoalbuminemic/medically frail patients (defined by modified frailty index), and hypoalbuminemic/frail patients. We performed both univariate and multivariate analyses to quantify the risk conferred by each condition in isolation, and in coexistence.ResultsOf 179,702 elective TKA cases from 2006 to 2018, 18.6% of patients were frail only, 3.0% were hypoalbuminemic -only, and just 1.2% were both frail and hypoalbuminemic. The raw rate of any complication was highest in frail/hypoalbuminemic patients (8.7%), 5.2% in hypoalbuminemic patients, 4.8% in frail patients, and just 3.4% in healthy patients (P < .001); the multivariate model revealed odds ratio of a complication in frail/hypoalbuminemic group of 2.40 (95% confidence interval = 1.27-1.63; P < .001). Mortality within 30 days was highest in the frail/hypoalbuminemic cohort (1.0%), and just 0.1% in healthy patients, and the multivariate model noted an odds ratio of 9.43 for these patients (95% confidence interval = 5.92-14.93; P < .001). The odds of all studied complications were highest in the frail/hypoalbuminemic group.ConclusionFrailty and hypoalbuminemia represent distinct conditions and are independent risk factors for a complication after TKA. Their coexistence imparts a synergistic association with the risk of post-TKA complications.