保存标本的时间和温度对血细胞参数的影响

目的 探讨同一批标本在不同的时问、不同的保存温度在同一部全自动血细胞分析仪对测定结果的影响。方法 采集20例本院健康体检者静脉血每位4m1分别注入2组EDTA-K2真空抗凝管中每管各2ml，其中一组在室温保存，另一组在4℃冰箱保存，用雅培CELL-DYN1700全自动血细胞分析仪，分别于采血后0、4、8、24h进行检测。结果 室温标本随着时间的延长对结果有影响，保存在4℃的标本在24h内完成除MPV外基本保持恒定。结论 血液标本采集后应尽量在4h内检测完毕，在4℃条件下保存，放置时间也不宜过长。     

保存标本的时间和温度对血细胞参数的影响

目的探讨同一批标本在不同的时间、不同的保存温度在同一部全自动血细胞分析仪对测定结果的影响.方法采集20例本院健康体检者静脉血每位4ml分别注入2组EDTA-K2真空抗凝管中每管各2ml,其中一组在室温保存,另一组在4℃冰箱保存,用雅培CELL-DYN1700全自动血细胞分析仪,分别于采血后0、4、8、24h进行检测.结果室温标本随着时间的延长对结果有影响,保存在4℃的标本在24h内完成除MPV外基本保持恒定.结论血液标本采集后应尽量在4h内检测完毕,在4℃条件下保存,放置时间也不宜过长.     

血液标本保存温度和时间对血小板系统检测指标的影响

本文探讨血液标本保存温度和时间对血小板系统检测指标的影响。     

标本温度、存储时间对肝功能生化检验结果的影响

目的 探讨标本温度、存储时间对肝功能生化检验结果的影响,为提高检验质量提供重要依据。方法 选取2018年10月~2019年2月我院检验科接受肝功能生化检验的200例健康者作为研究对象,均采集晨起空腹外周静脉血3.0 ml/管,共6管,比较常温及4℃环境,即刻及存储12 h检验,溶血及无溶血标本中肝功能生化指标水平。结果 无溶血标本的DBIL、AST、ALT、ALB水平高于溶血标本,ALP、TP、TBIL水平低于溶血标本,差异有统计学意义（P＜0.05）。常温与4℃保存标本的DBIL、TBIL、AST、ALT、ALB、ALP、TP水平比较,差异无统计学意义（P＞0.05）。即刻与存储12 h标本的DBIL、TBIL、AST、ALT、ALB、ALP、TP水平比较,差异无统计学意义（P＞0.05）。结论 血样标本保存温度、存储时间对肝功能生化检验结果影响甚微,但是溶血会对检验指标产生一定影响,因而在采血后特别注意标本状态变化,规避溶血现象,以保证检验结果的准确性。     

温度和时间对PT、APTT检测的影响

目的了解采血后放置时间，温度对阳、APTT测定结果的影响。方法将血浆分别置于4℃、20℃、37℃，严格按操作规程分别检测0、1、2、4、8h的阳、AfyIT值。结果在4℃8h、20℃8h、37℃2h，PT、APTT与0h测定结果有显著性差异。结论胛、APTT的测定应在4℃4h、20℃4h、37℃1h内完成。     

粉体粒径对碳酸化羟基磷灰石水泥固化时间和压缩强度的影响

目的　检测不同粉体粒径对碳酸化羟基磷灰石水泥 (carbonatedhydroxyapatitecement,CHC)的固化时间和压缩强度的影响 ,为其修复骨缺损提供理论基础。方法　采用研磨和超细粉体技术制备 4 0 0目、6 0 0目和超细粉体粒径的CHC干粉 ,检测不同粉体粒径对CHC固化时间和压缩强度变化。结果　超细CHC干粉平均粒径为3.10 9μm ,比表面积为 2 .2 88m2 /cm3 ,在 37℃、10 0 %湿度条件下CHC固化时间随粉体粒径减小而缩短 ,而固化后压缩强度随粉体粒径缩小而升高 ,超细粉体CHC初凝时间 3min ,终凝时间 8min ,最终固化后压缩强度 (5 1.0 4 2± 3.72 8)MPa。结论　超细CHC具有原位固化性能 ,固化时间合理 ,压缩强度高 ,比较符合临床使用的要求     

不同温度和时间对血常规参数检测结果的影响

目的探讨EDTA-K2抗凝静脉血在不同温度和时间对血常规参数检测结果的影响。方法运用XT-1800i全自动血细胞分析仪测定91份在不同温度下保存不同时间的血标本,其中31份血标本于4℃冷藏,并于0.5h、24h、48h、72h测定。30份血标本20℃保存,于0.5h、2h、4h、8h、24h测定;另30份血标本20℃保存,于24h、48h、72h再测定,各以0.5h测定结果为对照组,观察血常规参数检测结果变化。结果 20℃保存24h,WBC、RBC、Hb、MCH及WBC与对照组差异均无统计学意义(P>0.05),16种血常规参数差异均有统计学意义(P<0.05);20℃保存72h,WBC、RBC、Hb差异均有统计学意义(P<0.05),16种血常规参数从24h即有明显的变化,差别有统计学意义(P<0.05);4℃冷藏72h,WBC、RBC、MCH、Hb在72h内比较稳定,HCT、PLT及WBC分类在48h内比较稳定,14种血常规参数在24h有明显变化。结论血常规标本4℃冷藏,血细胞参数结果较稳定,但仍要考虑到个别参数的变化,以便于为临床提供更可信的数据。     

两种塑化材料对断层解剖标本制作效果的比较

目的:研究2种不同塑化材料制作的断层解剖标本的差异.方法:分别采用硅橡胶技术和聚酯共聚体技术制备人体断层标本,并进行比较.结果:硅橡胶技术所制备的标本不透明;聚酯共聚体技术制备的断层解剖标本半透明.硅橡胶材料制备的断层标本不适于研究组织纤维走向和筋膜结构,适用于标本防腐保存;聚酯共聚体材料制备的断层标本可以清晰地显示组织的纤维走向和筋膜结构,同时标本的厚度均匀,表面平滑,硬度较高.结论:聚酯共聚体材料制备的断层标本优于硅橡胶材料,此方法将会发展成为断层解剖学研究的常用技术.     

固化光源的种类对复合树脂充填材料固化收缩量的影响

本文研制开发了测量复合树脂固化收缩量的实验装置和检测方法。该装置采用激光测距传感器(测量精度为 1μm)和特制的材料固化腔 ,可以直接在光固化机照射的同时 ,测量复合树脂固化收缩的全过程。研究中采用 3种光固化机对 4种复合树脂材料进行 2种照射时间的固化收缩实验。经对实验结果分析发现 :复合树脂的固化收缩量的大小与固化光源的种类有关 ,用高能氙灯光源照射产生的固化收缩量最小 ;采用高能氙灯光源照射时固化收缩量小 ,并不完全是由于照射时间短 ,使复合树脂固化反应不充分所致 ,而是与光源本身的特性有关。     

放射免疫分析内皮素时温度和标记抗原作用时间改变的影响

观察了ＲＩＡ测定ＥＴ过程中1 2 5Ｉ-ＥＴ加入后各时间段的结果变化 ,并对 6个时间段进行了灵敏度、回收率、重复性试验材料和方法一、仪器和试剂 :(一 )仪器 :中国科大实业公司佳光仪器分公司ＧＣ - 12 0 0型γ计数器。(二 )试剂 :解放军总医院科技开发中心放免所提供的内皮素放免试剂盒。二、标本 :随机采集门诊病人静脉血 4 8例 (男 2 9,女 19) ,年龄 19～ 72岁。三、方法 :(一 )取静脉血 4ｍｌ加入含 6 0 μｌ 10 %ＥＤＴＡ -Ｎａ2 和 80 μｌ抑肽酶的试管混匀 ,4℃ ,30 0 0ｒｐｍ离心 10分钟分离血浆。(二 )取血浆 10 0 μｌ抗血清 10 …     

Damped oscillation analysis of natural and artificial periodontal membranes

The mechanical mobility of human teeth was studied by using a wave data treatment system with an accelerometer attached to a personal computer. The healthy teeth in different generations of men and women, who ranged in age from their teens to their forties, showed similar damped oscillation patterns. The spring constant and coefficient of viscous damping were estimated by using a viscoelastic model of damped oscillation with 1 degree of freedom. The coefficient of viscous damping increased dramatically with increases in the damping factor, whereas the spring constant scarcely varied. Silicone membranes were used as model periodontal membranes. The coefficient of viscous damping decreased with increases in silicone membrane thickness. Collagen membranes, which are expected to function as artificial periodontal membranes, were adhered to the model tooth by drying collagen gel and fixed with apatite-collagen composites. The collagen membranes showed damped oscillation wave patterns similar to those of human periodontal membranes.     

Respective roles of organic and mineral components of human cortical bone matrix in micromechanical behavior: an instrumented indentation study

Bone is a multiscale composite material made of both a type I collagen matrix and a poorly crystalline apatite mineral phase. Due to remodeling activity, cortical bone is made of Bone Structural Units (BSUs) called osteons. Since osteon represents a fundamental level of structural hierarchy, it is important to investigate the relationship between mechanical behavior and tissue composition at this scale for a better understanding of the mechanisms of bone fragility. The aim of this study is to analyze the links between ultrastructural properties and the mechanical behavior of bone tissue at the scale of osteon.Iliac bone biopsies were taken from untreated postmenopausal osteoporotic women, embedded, sectioned and microradiographed to assess the degree of mineralization of bone (DMB). On each section, BSUs of known DMB were indented with relatively high load (∼500 mN) to determine local elastic modulus (E), contact hardness (H_c) and true hardness (H) of several bone lamellae. Crystallinity and collagen maturity were measured by Fourier Transform InfraRed Microspectroscopy (FTIRM) on the same BSUs. Inter-relationships between mechanical properties and ultrastructural components were analyzed using multiple regression analysis.This study showed that elastic deformation was only explained by DMB whereas plastic deformation was more correlated with collagen maturity. Contact hardness, reflecting both elastic and plastic behaviors, was correlated with both DMB and collagen maturity. No relationship was found between crystallinity and mechanical properties at the osteon level.     

人牙咬痕形态学变化的生物力学研究

从生物力学角度研究人牙咬痕形态学变化的动态过程。以不同形态的牙和不同量的牙合力造成活体和死亡动物的咬痕 ,长时间动态追踪观察其变化过程 ,并测定相关形态参数 ,多元逐步回归分析咬痕形态与牙合力、时间、牙形态包括牙面积、牙宽度、牙厚度之间的关系 ,建立了咬痕形态学变化与多个力学、形态学因素的内在数学关系。     

单极子微波热疗天线在生物组织中产生的温度分布的调控

微波热疗的关键是实现微波能量长时间较均匀加热肿瘤组织。采用连续加热方法，在不改变天线结构及插入位置的条件下．很难实现对治疗区域的长时间均匀加热。我们结合电磁场的时域有限差分（Finite Difference Time Domain，FDTD）和温度场的有限差分方法模拟微波热疗天线在生物组织中产生的温度分布，通过调整天线的加热功率，并采用分时间隔加热的治疗方法，实现了微波能量对一定区域组织的长时间较均匀加热。     

Effect of temperature and calcium on force-frequency relationships in mammalian ventricular myocardium

Summary The effects of temperature and calcium on force-frequency relationships in mammalian ventricular myocardium were studied in isolated papillary and ventricular muscle bundles. Tensions, velocities, and phase durations were determined from the isometric tension record and its first derivative. Decreasing bath temperature from 34–36°C to 27–31°C increased contractile tension and prolonged the phases of contraction in rat, guinea pig, and adult and fetal human tissues without altering the force-frequency relationship. Doubling extracellular [Ca⁺⁺] beyond the 2.7 mM control for human tissue increased contractile tension and shortened phase I, and made the force-frequency relationship less steep or biphasic. These results suggest that the negative force-frequency relationship in the failing human heart cannot be explained merely on the basis on unavailability of Ca⁺⁺ to the contractile proteins.This research was partially supported by Grant 1104 of the Research Foundation of the City University of New York.     

Effect of muscle temperature on leg extension force and short-term power output in humans

Summary The effect of changing muscle temperature on performance of short term dynamic exercise in man was studied. Four subjects performed 20 s maximal sprint efforts at a constant pedalling rate of 95 crank rev · min⁻¹ on an isokinetic cycle ergometer under four temperature conditions: from rest at room temperature; and following 45 min of leg immersion in water baths at 44; 18; and 12‡ C. Muscle temperature (Tm) at 3 cm depth was respectively 36.6, 39.3, 31.9 and 29.0‡ C. After warming the legs in a 44‡ C water bath there was an increase of ∼11% in maximal peak force and power (PP_max) compared with normal rest while cooling the legs in 18 and 12‡ C water baths resulted in reductions of ∼12% and 21% respectively. Associated with an increased maximal peak power at higher Tm was an increased rate of fatigue. Two subjects performed isokinetic cycling at three different pedalling rates (54, 95 and 140 rev · min⁻¹) demonstrating that the magnitude of the temperature effect was velocity dependent: At the slowest pedalling rate the effect of warming the muscle was to increase PP_max by ∼2% per ‡ C but at the highest speed this increased to ∼10% per ‡ C.     

人体跖骨显微硬度的分布特征研究

目的 探讨人体跖骨显微硬度的分布特征。方法 选取年龄＞40岁(性别不限)、既往身体健康、无慢性病史的新鲜冰冻成人尸体3具,来源于河北医科大学解剖学教研室,取出全部右足,剔除软组织。用高精慢速锯于第1~5跖骨基底、跖骨干、跖骨头3个节段,垂直于其长轴进行切割,将骨骼制成若干厚3 mm的试样,并用砂纸打磨。应用维氏方法测量标本跖、背、内、外侧不同区域的硬度值,在跖骨头和跖骨基底标本测量松质骨的硬度值,在跖骨干标本测量皮质骨的硬度值。采用50 g力加载50 s、维持12 s标准操作方法测定,同一区域选取5个有效值,全体有效值的平均值作为该部位的硬度值。结果 选取45个骨骼区域,共制备45个骨组织试样,测量900个位点。跖骨硬度分布规律基本保持一致,跖骨硬度为(36.35±7.43) HV,其中第三跖骨硬度最大为(38.95±9.01)HV;跖骨干硬度高于跖骨头和跖骨基底,分别为(40.95±6.65)、(34.86±6.68)、(33.25±6.64)HV,差异有统计学意义(F=111.831, P＜0.01),而跖骨跖侧、背侧、内侧、外侧的硬度分别为(36.11±7.05)、(36.32±7.49)、(36.69±7.79)、(36.28±7.42)HV,差异无统计学意义(F=0.246, P>0.05)。结论 本研究首次报道了人体跖骨显微维氏硬度的分布特征;了解不同部位间的骨显微硬度差异,可帮助骨科医师在该部位骨折内固定手术中,正确选择钢板放置的位置,置钉的密度和方向等,从而获得更加合理的固定效果。本研究结果还可为未来设计硬度和弹性模量与人体生理特点更加接近的接骨板、螺钉、人工骨等奠定了理论基础和数据支持。     

The visual guidance of catching

In order to explore the nature and amount of information in the optic array used by subjects required to carry out one-handed catching actions, the optical expansion pattern (using a deflating ball) and the duration of viewing time (using liquid crystal spectacles) of the ball were varied. Subjects were required to catch luminous balls (two of constant physical size and one of changing physical size during approach) attached to a pendulum in a totally dark room, while the liquid spectacles were closed at 0, 100, 200 or 300 ms before hand-ball contact. The results confirmed previous findings that the timing of the catching action is based on retinal expansion information and that conclusion was strengthened when an additional dependent variable (time of the maximal opening velocity of the grasp) was used. Further, for the viewing time duration manipulations, the time of the maximal closing velocity of the hand was later, while no effect was found on the time of the maximal opening velocity, when the last 300 ms of the trajectory of the ball was occluded. Adjustments to the catching action in response to the different ball sizes under the 0 ms condition differed significantly from the adjustments under the 300 ms condition. Both findings point to the importance of relative optical expansion information, available between 300 and 200 ms before ball-hand contact, in maintaining a (relatively) continuous perception-action coupling in the act of catching.     

A common processing system for duration, order and spatial information: evidence from a time estimation task

The aim of the present study was to verify whether duration, order and space representations share common mechanisms. A two-alternative time estimation paradigm was implemented in two experiments in which subjects had to judge whether the first or the second tone in a pair was shorter (or longer) and to respond by pressing a left or a right key. In Experiment 1, subjects were more accurate in conditions where the first tone was shorter or the second tone was longer, with no effects of spatial information. In Experiment 2, a modification of the paradigm allowed us to demonstrate the presence of a SNARC-like effect, as evidenced by the interaction between order and response key, and of a second-order interaction among duration, order and space. These findings seem consistent with the hypothesis that processing of these three mental categories is subserved by a common mechanism, representing duration and order information according to a spatially-defined magnitude system.     

The effect of aging on visual-vestibuloocular responses

To determine age-related changes in oculomotor function we measured vestibuloocular (VOR), optokinetic (OKN), and visual-vestibular responses in a large group of normal subjects over the age of 75 years and compared the results with those from a group of young adults. Compared with the young subjects, older subjects had: (1) an amplitude-dependent decrease in VOR gain, (2) a shorter dominant VOR time constant, (3) a lower OKN slow-phase velocity saturation, and (4) a decreased ability to enhance and suppress the VOR with vision. These functional changes in older subjects are presumably secondary to well-documented, age-related changes in the sensory and neural elements of the visualvestibulooculomotor pathways. They may be a contributory factor to the common complaints of dizziness and dysequilibrium in people over the age of 75 years.