人肝癌细胞Hep-G2的冷冻干燥保存初探

冷冻干燥是长期有效保存细胞的手段之一。本文以肝癌细胞Hep-G2为研究对象,选取了不同体积分数的Me2SO、丙三醇及不同质量浓度的PVP、复方保护剂进行冷冻干燥保存,筛选出最佳保护剂配方。此外,将细胞在不同摩尔浓度的海藻糖溶液中孵育,通过检测细胞回收率、存活率和24 h贴壁率,探究胞内海藻糖对细胞冷冻干燥的影响。结果表明:添加40%PVP(w/v)+10%甘油(v/v)+15%FBS(v/v)+20%海藻糖(w/v)保护剂的细胞,在复水后回收率、存活率和24 h贴壁率分别为29.58%、42.18%和18.71%,与对照组相比三项指标均得到有效提高,该种保护剂的效果最佳;当胞外海藻糖摩尔浓度为800 mmol/L时,冻干效果最好,肝癌细胞Hep-G2在复水后回收率、存活率和24 h贴壁率分别为27.81%,66.65%和33.68%,存活率和贴壁率显著高于其他组。     

人体骨髓基质干细胞冷冻干燥的探索性实验

人体骨髓基质干细胞已成为组织工程、细胞移植和基因治疗等领域的重要研究对象,目前对它已有低温保存的研究,而通过冷冻干燥的方法对其进行保存国内外未见报导.实验尝试用冻干的方法来保存骨髓基质干细胞.文中选取海藻糖、PVP、HES等作保护剂,应用差示扫描量热仪(DSC)测量其结晶温度和玻璃化转变温度;随后对加入保护剂的细胞溶液进行冻干实验,并应用流式细胞仪对冻干样品复水后的细胞活性进行了测定,其中30%PVP 20%海藻糖对细胞的保护效果较好,细胞成活率达到16.40%.     

冷冻干燥保存人脐血实验研究

尝试用冷冻干燥法来长期保存脐血和有核细胞,并对冻干效果进行比较分析.选用聚乙烯吡咯烷酮(PVP)、蔗糖和甘露醇等作为冻干保护剂,先将样品冻结到-38℃,随后在-30℃搁板温度下进行升华干燥,最后在15℃搁板温度下进行解吸干燥.冻干后的样品用磷酸盐缓冲液复水,然后用血细胞计数板、流式细胞仪和扫描电镜进行检测.实验结果表明:在400 g/L PVP 200 g/L蔗糖 100 g/L甘露醇作为保护剂时细胞数目恢复率最高,为(75.0±4.1)%(P＜0.01),PI染色鉴定测得单个核细胞拒染率在400 g/L PVP 200 g/L蔗糖 10%胎牛血清作为保护剂时最高,为(98.57±0.68)%(P＜0.01),CD34 细胞回收率最高为35.59%.最终确定有核细胞的冻干效果比全血的要好,初步判定冷冻干燥法保存脐血是可行的.     

苹果冷冻干燥过程的实验研究

本对苹果的冷冻干燥过程进行了实验研究,分析了冻干曲线的特征,比较了降温速率、真空度、加热板温度以及冷阱温度对冷冻干燥和冻干品质量的影响,对实际冷冻干燥生产具有一定的指导作用。     

冷冻干燥过程传热传质研究

本文通过建立冻干过程传热传质的理想计算模型，分析了冻干中传热传质过程及其相互关系，推导出冻干周期计算公式及影响冻干周期的各参数     

眼角膜真空冷冻干燥保护剂

离体生物组织的冻干贮藏是真空冷冻干燥技术应用的重要领域,而冻干生物制品的保护剂是冻干工艺中不可缺少的制剂。着重介绍了真空冷冻干燥眼角膜时所用保护剂种类、作用和保护机理。     

食品冷冻干燥技术的研究

随着科学技术进步的经济的发展，人们对食品的要求日趋理性化。传统以保藏为目的的食品加工，满足了人们消费动、植物食品不受季节和地域限制的需求，但加工出来造成的营养成分、生理活性成分的损失，色、香、味的劣变，以及过分依赖添加剂等所引起的安全性等问题，日益被消费者所关注和担忧。随着人们生活水平的提高，及对饮食快捷化、方便化的迫切需求，人们对待“吃”的观念已由过去的吃饱吃好转向注重饮食的快捷与营养及安全并重，使得冻干食品应运而生，并给冻干食品的发展提供了机遇。本文研究了冻干食品的特点和食品冷冻干燥技术的有关技术问题。     

泡沫真空冷冻干燥的实验研究

本文对泡沫冷冻干燥保护剂的配方及过程参数进行了四因素三水平的正交实验研究,确定了各因素对发泡效果影响的显著性。其中发泡真空度对发泡高度的影响最显著,明胶及Pluronic-F68用量其次,搁板温度的影响最不显著。应用发泡效果最佳的配方及过程参数,进行了1 ml样品的泡沫真空冷冻干燥实验,一次干燥时间3 h、二次干燥时间12 h,所得样品剩余含水量小于2.0%。     

真空冷冻干燥猕猴桃粉工艺的研究

针对猕猴桃常规干燥保存过程中不易成粉且化学添加剂过多等问题,本文比较了热风干燥、喷雾干燥、冷冻干燥3种干燥方式下猕猴桃粉的品质,并研究了冷冻干燥法制备猕猴桃粉过程中,预冻方式、浆体比例、助干剂种类、猕猴桃新鲜度等因素对猕猴桃粉品质的影响。结果表明：相比热风和喷雾干燥,冷冻干燥法制备的猕猴桃粉综合品质较好、速溶性好、产率较高;采用冻干法制备猕猴桃粉的较优工艺为选取九成熟（盛花后约175天）的猕猴桃去皮打浆,以体积比（猕猴桃浆：酸奶）1∶1添加酸奶,铺料厚度4mm,经-20℃预冻后,在真空环境下干燥10h。     

甘油对人的红细胞冷冻干燥保存效果的影响

就甘油对人红细胞冷冻干燥保存效果的影响进行了实验研究。实验中先用不同浓度的甘油对红细胞进行处理，用PVP、柠檬酸钠、蔗糖和胎牛血清作为冻干保护剂对红细胞进行冻干保存，冻干后的样品用质量浓度为30g／L的NaCl复水，用血球分析仪和光镜进行检测。实验结果表明；用甘油进行处理后，红细胞的回收率明显高于没有用甘油处理的红细胞组。其中，采用质量浓度为400g／L的甘油处理后，红细胞冻干回收率达到51．4％。     

The influence of blood on targeted microbubbles

The ability to successfully target the delivery of drugs and other therapeutic molecules has been a key goal of biomedical research for many decades. Despite highly promising in vitro results, however, successful translation of targeted drug delivery into clinical use has been extremely limited. This study investigates the significance of the characteristics of whole blood, which are rarely accounted for in vitro assays, as a possible explanation for the poor correlation between in vitro and in vivo experiments. It is shown using two separate model systems employing either biochemical or magnetic targeting that blood causes a substantial reduction in targeting efficiency relative to saline under the same flow conditions. This finding has important implications for the design of targeted drug delivery systems and the assays used in their development.     

基于微流血型检测卡的血型判读试验

为验证微流血型检测卡可实现血型检验工作,搭建自动化血型检测硬件平台,将微流血型检测卡作为反应容器,充分反应后把原始图像分割为单通道图像,直接取用R通道像素值进行灰度化,再使用Sobel算子提取边缘信息,最后用图像信息熵的方法得到图像信源的平均信息量,即可获得血型判读结果。实验结果表明:数字图像处理能够快速有效地判读血型信息,并通过重复性测试得知适于大样本检测,所以使用微流血型检测卡能够完全满足全自动血型分析仪的血型判读要求。     

Is there the potential for an epidemic of variant Creutzfeldt–Jakob disease via blood transfusion in the UK?

The discovery of three individuals suspected to have contracted variant Creutzfeldt-Jakob disease (vCJD) through blood transfusions has heightened concerns that a secondary epidemic via human-to-human transmission could occur in the UK. The Department of Health responded immediately to this threat by banning those who had received blood transfusions since 1980 from donating blood. In this paper, we conduct a sensitivity analysis to explore the potential size of a blood-borne vCJD epidemic and investigate the effectiveness of public health interventions. A mathematical model was developed together with an expression for the basic reproduction number (R0). The sensitivity of model predictions to unknown parameters determining the transmission of vCJD via infected blood was assessed under pessimistic modelling assumptions. We found that the size of the epidemic (up until 2080) was bounded above by 900 cases, with self-sustaining epidemics (R0>1) also possible; but the scenarios under which such epidemics could arise were found to be biologically implausible. Under optimistic assumptions, public health interventions reduced the upper bound to 250 and further still when only biologically plausible scenarios were considered. Our results support the belief that scenarios leading to large or self-sustaining epidemics are possible but unlikely, and that public health interventions were effective.     

改进试验设计法优化电动汽车按时间租赁利润

针对电动汽车租赁服务系统,结合顾客到达率瓶颈、顾客依据感知价值选择服务的特征及电动汽车特性,构建了按时间收费利润模型。以利润最大化为目标,采用改进试验设计法求解模型。先采用传统试验设计法求出最佳利润及因素取值组合,确定利润函数在最佳因素取值组合处的单调性,进而更精确地判断可取得最优利润的因素水平取值区间,根据精确化后的取值区间并保持各因素水平数不变,采用试验设计法再次优化利润。实例分析比较了试验设计法改进前后所得利润优化结果,显示改进后方法得出的利润显著更优,验证了模型的有效性和实用性。     

Hemolysis-induced acute pancreatitis secondary to kinked hemodialysis blood lines

Hemolytic reactions have become extremely rare in chronic maintenance hemodialysis. We present the case of a young dialysis patient with hemolysis-induced acute pancreatitis secondary to kinked hemodialysis blood lines. With new blood lines on the market, attention to this aspect of dialysis is mandatory.     

Finite-element simulation of firearm injury to the human cranium

An advanced physics-based simulation of firearms injury to the human cranium is presented, modeling by finite elements the collision of a firearm projectile into a human parietal bone. The space-discretized equations of motion are explicitly integrated in time with Newmark's time-stepping algorithm. The impact of the projectile on the skull, as well as the collisions between flying fragments, are controlled through a nonsmooth contact algorithm. Cohesive theories of fracture, in conjunction with adaptive remeshing, control the nucleation and the propagation of fractures. The progressive opening of fracture surfaces is governed by a thermodynamically irreversible cohesive law embedded into cohesive-interface elements. Numerical results compare well with forensic data of actual firearm wounds to human crania.     

A Combinatorial and Informatics Approach to CdS Nanoclusters

The stabilization of size‐specific monodisperse CdS nanoclusters has received much attention. However, the development of matrices, e.g., polymers, micelles, zeolites, for this purpose has remained largely empirical. Here a combinatorial and informatics approach to the discovery of ligands for CdS nanocluster stabilization is introduced. It is shown that combinatorially derived peptide and peptidomimetic ligands based on phytochelatins can stabilize CdS nanoclusters and that an informatics analysis of the library used yields design parameters critical for obtaining second‐generation ligands.     

基于谱峭度的不确定性振源监测方法

强噪声环境下实现不确定性振源的监测对于机械和建筑结构的诊断和维护工作有着重要的实际工程意义。通过介绍一种在信号频域应用峭度参数进行未知振源检测的新方法,即谱峭度方法,并经过实测试验对该方法的特点进行分析,提出在检测不确定性振源的同时对其在频域定位的方法。采用实测数据验证方法的有效性,并取得很好的效果。