3D虚拟复原精度的差异对头骨测量数值的影响——以Mimics软牛为例

近年来,根据三维软件虚拟复原的头骨来获取测量数据的方法被越来越多地应用在古生物,特别是古人类学的研究中,然而对于三维软件不同精度虚拟复原的头骨,其测量数值是否有差异,研究者并不是很清楚。本文以Mimics软件为例,根据其复原模型简化规则,选择未精简的最佳精度模型作为标准进行配对t检验或非参数检验,通过对43例云南人头骨的顶骨矢状弦长、颅周长、头盖部面积、乳突小房表面积、颅容量、乳突小房体积等六个测量项目的对比和分析,对Mimics软件低、中、高、最佳四种精度3D虚拟复原头骨间的测量差异进行了研究。结果显示：颅周长、头盖部面积、颅容量、乳突小房体积四项的所有简化精度模型的测量数据均与最佳精度模型测量数据的差异具有显著性;而除高精度组外,顶骨矢状弦长及乳突小房表面积的其余精度组测量数据均与最佳精度组差异具有显著性;此外,顶骨矢状弦长、颅周长、头盖部面积、颅容量的简化精度与最佳精度的测量差异占比均小于3%.而乳突小房表面积的低精度与最佳精度测量差异占比可超过50%,乳突小房体积的低精度与最佳精度测量差异占比可超过120%。这一结果提示我们,在测量Mimics复原的三维模型时,体量大差异小的测量项可以在较低精度的复原模型上进行测量;而对头骨内部腔窦这样体量小表面粗糙的结构,复原模型的精度选择及测量数据比较需要格外谨慎。     

氢离子选择性微电极细胞内pH测量系统的研制

本文叙述我们建立的以 IBM PC/XT 兼容机为核心的细胞内 pH 值的测量系统。着重说明对氢离子敏感的离子选择性微电极的制作方法,与其连接的极高输入阻抗的微电极放大器的设计,以及为提高测量的精度而采取的多种措施。阐述了系统的性能、并对其测量精度、优缺点进行了分析与讨论。     

《血气分析应用软件》简介

目前,血气分析实验在国内逐步开展。通常血气分析报告需要经过计算和查表才能得到其他有关数据。应用微机综合计算分析血气结果并输出具有参考意义的实验诊断报告,无疑能对临床及实验室判断酸碱气体紊乱提供方便。上海市第五人民医院应用微机处理血气报告2000多例,诊断结论基本上与临床相符,能满足临床的要求。利用微机处理血气质控数据,绘制质控图(图1),快速且直观,能直接了解血气质控的情况,使实验质量进一步提高。利用微机还可以储存大量的第一手血气分析资料。 欲购《血气分析应用软件》及医院管理方面的几十种计算机软件,请您参加1988年11月在上海举行时“微机     

一种在直径线方向拟合多项式的树干解析方法

本文介绍了一种操作简便、精度较高的圆盘解析测量方法:先在圆盘上放置刻度尺,利用数码相机拍摄圆盘以获得数字影像,通过计算机软件对数字影像校正,并进行每圈年轮半径的测量;然后,依次点选直径线与每圈年轮的交点,算出交点和髓心之间的坐标距离,并代入拟合方程,即可得到年轮的径向尺寸。分析结果显示,此方法测量半径的最大误差为0.007650 cm,最小误差为0.000040 cm,平均误差为0.002477 cm,而常规的毫米刻度尺测量方法的精度仅达到毫米与亚毫米级,大型专业的树木年轮分析仪器精度一般精度范围在0.0005~0.0010 cm。此方法具有成本低、方便快捷、操作简单、精度较高等优点,是一种有推广价值的树木年轮半径测量方法,对分析树木生长过程具有重要意义。     

强化护理质量控制对提高血气分析结果准确性的研究

目的探讨护理质量控制对血气分析结果准确性的影响。方法选择我院EICU病房需行动脉血气分析的患者100例分为对照组和实验组各50例,对照组实施常规方法采集送检,实验组在采集过程中对分析前负性因素加强护理质量控制,评估两组患者血气分析结果的准确率并分析。结果对照组50例,直接穿刺动脉采集标本356次,其中28次标本因为各种原因重新采集,准确率为92.1%;观察组50例,直接穿刺动脉采集标本368次,其中13次标本因为各种原因重新采集,准确率为96.5%,差异有统计学意义(P0.05)。结论血气结果的准确率与采血时患者状态、采血部位及采血的具体操作密切相关,加强对这些因素的护理质量控制,可明显提高血气分析结果的准确性,为临床诊治提供依据。     

浅谈使用血气酸碱分析仪的三个要素

由于血液气体酸碱分析(简称血气、下同),在治疗呼吸衰竭(或呼吸困难)和酸碱失衡两个临床综合症方面有其明显的指导意义,近10余年来,血气的开展日益受到重视。由于诸多原因,血气仪的使用常不顺利,以至于不少医院的血气仪常常处于待修或长期废用的状态,血气分析仍然得不到开展,造成业务和经济上的损失。笔者最近获知,某地区同时引进9台血气仪,在一年内仅只有1台是顺利工作的,其余8台基本处于瘫痪状态。后经厂方专程集中检修,发现仪器故障均与使用保养不当直接有关,而主     

多尺度遥感综合监测我国北方典型草原区植被盖度

利用多尺度遥感影像综合进行全球和区域尺度的土地利用/覆盖变化(LUCC)研究是最近全球变化研究的重要方向之一。本文综合利用野外群落样方、数字相机、ETM+影像、NOAA/AVHRR影像,在遥感、GIS和GPS支持下,对我国北方典型草原区植被盖度进行了综合监测、模拟与分析。结果表明:(1) 利用经处理后的数字相机影像测量盖度的结果准确性较高,可以作为植被盖度测量的标准结果,反映真实的覆盖特征,并用以验证利用其它方法测量结果的精度。(2) 利用野外1 m2样方网格法目视估测的植被盖度结果变化较大,不稳定。本次实验中,与数字相机测量结果相比,样方估测的盖度普遍偏高,平均偏差为9.92%;但两者相关性较好(r2=0.89)。(3) 采用Gutman模型ETM+影像、NOAA/AVHRR影像反演植被盖度的结果与数字相机测量结果偏差分别为7.03%、7.83%,ETM+像元分解NOAA像元后得到的植被盖度与数字相机测量结果偏差5.68%。三者与数字相机测量结果的相关系数r2分别为0.78、0.61和0.76。(4)利用野外实测植被盖度数据直接与NOAA-NDVI影像建立统计模型估算植被盖度的精度较低(r2=0.65),而通过空间分辨率介于两者之间的ETM+影像进行转换后,该精度得到一定的提高(r2=0.80)。利用像元分解的方法提高了大尺度植被盖度监测的精度,是利用遥感数据进行尺     

Mus和Rattus属鼠类下颌骨形态特征测量分析系统建立

目的建立高精度低误差的《Mus和Rattus属鼠类下颌骨形态特征测量分析系统》。方法运用Microsoft Visual Basic6．0语言设计程序,自动测量、计算、分析下颌骨形态特征。实例运行评估其可操作性。结果本系统可提高测量精度28倍,减少计算误差40余倍。可适用于Mus和Rattus属的野生动物、实验动物的下颌骨形态特征测量分析。结论《Mm和Rottus属鼠类下颌骨形态特征测量分析系统》具有成为可操作的遗传检测方法。     

多尺度遥感综合监测我国北方典型草原区植被盖度

利用多尺度遥感影像综合进行全球和区域尺度的土地利用/覆盖变化(LUCC)研究是最近全球变化研究的重要方向之一.本文综合利用野外群落样方、数字相机、ETM+影像、NOAA/AVHRR影像,在遥感、GIS和GPS支持下,对我国北方典型草原区植被盖度进行了综合监测、模拟与分析.结果表明:(1)利用经处理后的数字相机影像测量盖度的结果准确性较高,可以作为植被盖度测量的标准结果,反映真实的覆盖特征,并用以验证利用其它方法测量结果的精度.(2)利用野外1 m2样方网格法目视估测的植被盖度结果变化较大,不稳定.本次实验中,与数字相机测量结果相比,样方估测的盖度普遍偏高,平均偏差为9.92%;但两者相关性较好(r2=0.89).(3)采用Gutman模型ETM+影像、NOAA/AVHRR影像反演植被盖度的结果与数字相机测量结果偏差分别为7.03%、7.83%,ETM+像元分解NOAA像元后得到的植被盖度与数字相机测量结果偏差5.68%.三者与数字相机测量结果的相关系数r2分别为0.78、0.6l和0.76.(4)利用野外实测植被盖度数据直接与NOAA-NDVI影像建立统计模型估算植被盖度的精度较低(r2=0.65),而通过空间分辨率介于两者之间的ETM+影像进行转换后,该精度得到一定的提高(r2=0.80).利用像元分解的方法提高了大尺度植被盖度监测的精度,是利用遥感数据进行尺度转换研究的重要实践.多尺度遥感影像的综合对地观测对大区域上反演植被盖度有很好的促进作用.     

精制溶栓酶治疗慢性肺心病研究

用常规方法治疗慢性肺心病１０例,另加用精制溶栓酶治疗８例作对比研究,观察临床症状改善,血气分析、及部分血粘度指标变化情况,结果发现：加用溶栓酶组能使血气及血粘度指标更好改善,分析认为与溶栓酶的抗凝、去纤、扩血管、改善肺微循环作用有关。     

Hydrogen clearance: assessment of technique for measurement of skin-flap blood flow in pigs

The hydrogen clearance technique has been used for many years by investigators to determine brain blood flow and has been partially validated in this setting using other methods of blood flow measurement. The method has been modified to allow blood flow measurements in skin, but the accuracy of H2 clearance for measuring skin blood flow has not been determined. Multiple blood flow measurements were performed using H2 clearance and radioactive microspheres on skin flaps and control skin in pigs. On 12 pigs, a total of 117 flap and 42 control skin measurements were available for analysis. There was no significant difference between the two techniques in measuring mean control skin blood flow. In skin flaps, H2 clearance was significantly correlated to microsphere-measured blood flow, but it consistently gave an overestimate. Sources of error may include injury to the tissues by insertion of electrodes, consumption of H2 by the electrodes, or diffusion of H2 from the relatively ischemic flap to its well-vascularized bed. Further studies are necessary to determine the cause of this error and to measure the technique's accuracy in skeletal muscle and other flaps.     

On the elastic properties of arteries

A new coefficient of elasticity is proposed that relates to the elastic state of the blood vessels. This measure is proposed as a result of the realization, from personal experience as well as from the international literature, of the difficulty in measuring the thickness of the blood vessels in vivo with acceptable precision. The measurement of E being dependent on the measurement of the thickness of the vessels becomes a highly unreliable proposition. Its relation to E (Young modulus) and to the pulse wave velocity (PWV) is established. We give three examples showing how the proposed coefficient can be measured.     

Quantifying the Precision of Single-Molecule Torque and Twist Measurements Using Allan Variance

Single-molecule manipulation techniques have provided unprecedented insights into the structure, function, interactions, and mechanical properties of biological macromolecules. Recently, the single-molecule toolbox has been expanded by techniques that enable measurements of rotation and torque, such as the optical torque wrench (OTW) and several different implementations of magnetic (torque) tweezers. Although systematic analyses of the position and force precision of single-molecule techniques have attracted considerable attention, their angle and torque precision have been treated in much less detail. Here, we propose Allan deviation as a tool to systematically quantitate angle and torque precision in single-molecule measurements. We apply the Allan variance method to experimental data from our implementations of (electro)magnetic torque tweezers and an OTW and find that both approaches can achieve a torque precision better than 1 pN · nm. The OTW, capable of measuring torque on (sub)millisecond timescales, provides the best torque precision for measurement times$\mathrm{?}$10 s, after which drift becomes a limiting factor. For longer measurement times, magnetic torque tweezers with their superior stability provide the best torque precision. Use of the Allan deviation enables critical assessments of the torque precision as a function of measurement time across different measurement modalities and provides a tool to optimize measurement protocols for a given instrument and application.     

A high precision fluorometer for biochemical measurements

Fluorometric biochemical analyses based on the enzyme coupled NAD-NADH reaction are limited in sensitivity by sample background fluorescence. An order of magnitude improvement in sensitivity has been achieved with a fluorometer designed to automatically measure sample fluorescence with high precision, before and after the enzymatic reaction, to give a precise value for a small change in the fluorescence level. The design of this instrument has been optimized for precision of photometric measurement and includes automatic processing of 20 samples, automatic reagent addition, and digital signal processing. Performance tests show a capability for measuring changes in sample fluorescence of 1% with a precision of about 5%.     

Applications of the reflex instruments in quantitative morphology

The Reflex instruments are a set of non-contact measuring instruments enabling direct measurement in three dimensions of relatively small objects, or of stereophotographs. In addition to the range of geometric calculations which the standard software provided with the instruments can perform directly on the output of three-dimensional coordinates, the data can also be used to generate contour plots, three-dimensional computer representations, etc. The instruments have been used to measure hard tissues such a s teeth, jaws and vertebrae, soft tissues such as gums, leg ulcers an Drosophila, and impressions such a s footprints and bitemarks. Among the advantages of the instruments, in different studies their use has improved precision, speeded up measurement, avoided the need to take X-rays and avoided possible damage to objects.     

土壤羟胺还原酶活性测定方法的改进

对传统土壤羟胺还原酶活性的测定方法进行了部分改进.用煮沸并密封冷却的蒸馏水形成3～5 cm的液封,同时用N2气流排除液面以上的空气,能够创造测定土壤中羟胺还原酶活性所需要的厌氧环境.与传统方法相比,该方法减少了厌氧程度的不确定性和试验步骤的复杂性,增加了培养试验的可操作性.以碘量法为对照,对4种不同的测量浸提液中羟胺浓度的分光光度法进行了对比筛选,结果表明,硫酸铁铵-邻菲罗啉法具有较高的准确度和精密度,是测定土壤中羟胺还原酶活性的理想方法.     

Gas chromatographic analysis of therapeutic concentrations of maprotiline in serum, using flame-ionization detection

For the measurement of the tetracyclic antidepressant maprotiline in human serum, a gas chromatographic method with flame-ionization detection has been developed. The assay specifications obtained are as follows: a precision (C.V.) of 3.5–6.4%, and a relative recovery of 97–109% using amitriptyline as internal standard. The sensitivity of the assay from serum was 40 nmol/l. The applicability of the method has been shown by measuring steady-state serum levels of five inpatients. The steady-state serum levels of maprotiline given at a daily dosage of 75 mg varied from 272 to 570 nmol/l.     

On Errors of Measurement

When any process of measuring is considered, one of the basic questions is how to assess the precision of measurement methods and/or instruments. In this paper, this question is formulated and solved as a problem of tolerance regions for absolute and relative normaly distributed errors of measurements.     

Comparative physiological responses to stressors in animals.

1. The species-specific experimental response to stressors (SSERTS) analysis has been applied to a number of species under varied short and long term conditions. 2. The measure provides quantitative data relating to the physiological responses of animals when exposed to stressors and results are presented comparing these for different methods of immobilization, euthanasia, etc. at intra- and inter-species level. 3. It is suggested that the SSERTS measure is of greater value for measuring the responses of animals to stressors than is the measurement of the concentration of single blood variables.