Volume variation of mastoid pneumatization in different age groups: a study by three-dimensional reconstruction based on computed tomography images

Although there have been some reports that measured the size of mastoid pneumatization, only a few studies have reported the age-related variations in the mastoid air cell system using three-dimensional (3D) reconstruction techniques of computed tomography (CT) images. We performed a retrospective, cross-sectional study. A 3D reconstruction based on CT images was performed on 199 ears of 102 patients (age range 6–84 years) without otologic disease by a surface-rendering algorithm. The results showed that mastoid pneumatization continued to grow until the third decade. Thereafter, it declined slowly, and then rapidly after the seventh decade. No statistically significant difference was found between male and female or between right and left sides. There was a significant difference between the larger and smaller sides of individuals. The volume measurement technique based on the 3D reconstruction technique reported here is widely available, highly accurate and easy to perform.     

诊断X线机辐射剂量的测量

为提高诊断X线机的诊断质量,促进放射防护工作的开展,根据"国际辐射单位和测量委员会"(International Commission on Radiological Units and Measurements,ICRU),"国际放射防护委员会"(International Commission on Radiation Protection,ICRP)关于辐射对人体的损害之划分标准,作者对岛津制作所90年代中期生产的XEB150L-20型500mA X线机按照国家规定的要求及有关标准,分别对辐射空气释动能率,半价层,输入量重复性,输出量线性,高对比分辨率,光野与照射野一致性及X线管的焦点等参数进行了测试。分析了测试的数据与结果,并进行了简要的评价。     

寰椎的解剖学测量及其临床意义

目的　探讨寰椎因素致椎 基底动脉供血不足的发病机制及手术切开横突孔减压提供解剖学依据。方法　在5 0例中国成年人干燥寰椎标本上 ,对具有临床意义的数据进行解剖学测量。结果　寰椎横突孔与椎动脉沟的成角左侧为(6 7 87± 5 39)°,右侧为 (6 9 84± 4 5 5 )° ;椎动脉沟绕寰椎侧块成角 :左侧为 (6 2 4 6± 4 6 6 )°,右侧为 (6 3 6 1± 2 31)°。寰椎横突孔前壁厚度 :左侧为 (2 96± 0 5 4 )mm ,右侧为 (3 2 1± 0 4 0 )mm。横突孔后壁厚度 :左侧为 (2 2 8± 0 5 7)mm ,右侧为 (2 0 2± 0 2 6 )mm。以上数据左、右侧比较差异无显著性。结论　椎动脉行经在寰椎横突孔与椎动脉沟内时 ,在骨性结构上有明显的两个成角 ,即横突孔与椎动脉沟的成角和椎动脉沟绕过侧块的成角 ,椎动脉的这两个成角增加了血液循环的阻力 ,同时在头颈部旋转运动时 ,椎动脉与骨性成角间更加贴近 ,这两个成角与椎 基底动脉供血不足的发生有关。寰椎横突孔后壁较前壁薄 ,此数据可作炒寰椎横突孔后壁切开减压时手术参考依据     

不同年龄组儿童甲状腺测量值及其变化的研究

调查了90具童尸用状腺的基本形态,可分四型。其中以甲状腺由两侧叶及峡部组成者为最多,占50.22%。测量了甲状腺各部的长、宽、厚。分年龄组进行了数据的统计学处理,并计算出儿童与成人甲状腺各部相应值的百分比。结果显示:小儿甲状腺侧叶的长度和宽度在幼儿期(1—3岁)就已发育近成人的一半。随着年龄的增长,甲状腺各部的均值逐渐增加。除各部的宽度以及锥体叶的长度外,各相邻两组间同项均数的比较,经双侧T检验发现差异具有高度显著性(P<0.01)。     

A simple method for measurement of inulin in nanoliter samples using glass capillaries

Summary A simple method using glass capillaries instead of microcuvettes for measurement of inulin in nanoliter samples is given. Inulin was determined with anthron reagent (5 or 10 nl samples +3 l anthron reagent). Glass capillary tubes (o.d.=1 mm, i.d.=0.68 mm, length=150 mm) in which the chemical reaction took place during incubation at 56°C were directly introduced into the optical system of a Zeiss spectrophotometer PMQ II with sphere attachment and objective.Extinction was measured vertically to the axis of the capillary. The changes of extinction of 20 different capillaries with the blank at different positions was only 1.13×10^–3. The exactness of measurement in the concentration range of 100 200 400 750 1500 3000 mg-% inulin was for 5nl/3 l: 19.8 11.0 6.7 4.7 3.0 2.2%. 10nl/3 l: 13.0 8.4 5.1 3.9%.This method of measurement may also be applicable for other colorimetric reactions with nanoliter samples.This work was supported by Fonds zur Förderung der wissenschaftlichen Forschung.     

Online measurement of ocular accommodation using a low-cost microcomputer system

The paper describes a low-cost system for the measurement of ocular accommodation. Digitisation of the low-frequency signals obtained from the measurement is straightforward and high-speed methods are not necessary. The methods described are, therefore, of interest to workers involved in the study of low-frequency signals, which are common in biological systems.     

Comparison of frequency, intensity, and duration of aggressive responses in rats

Three judges were trained to evaluate the frequency, intensity, and duration of aggressive responses in rats. Intrajudge and interjudge reliability ranged from .84 to .99. Correlation coefficients between frequency, intensity, and duration of aggressive responses ranged from .89 to .99. All three measures were found to be highly reliable methods of measuring aggression.     

Compartmental Analysis of Breathing in the Supine and Prone Positions by Optoelectronic Plethysmography

Optoelectronic plethysmography (OEP) has been shown to be a reliable method for the analysis of chest wall kinematics partitioned into pulmonary rib cage, abdominal rib cage, abdomen, and right and left side in the seated and erect positions. In this paper, we extended the applicability of this method to the supine and prone positions, typically adopted in critically ill patients. For this purpose we have first developed proper geometrical and mathematical models of the chest wall which are able to provide consistent and reliable estimations of total and compartmental volume variations in these positions suitable for clinical settings. Then we compared chest wall (CW) volume changes computed from OEP( V _CW) with lung volume changes measured with a water seal spirometer (SP) ( V _SP)in 10 normal subjects during quiet (QB) and deep (DB) breathing on rigid and soft supports. We found that on a rigid support the average differences between V _SP and V _CW were –4.2% ± 6.2%, –3.0% ± 6.1%, –1.7% ±7.0%, and –4.5% ± 9.8%, respectively, during supine/QB, supine/DB, prone/QB, and prone/DB. On the soft surface we obtained –0.1% ± 6.0%, –1.8% ± 7.8%, 18.0% ± 11.7%, and 10.2% ± 9.6%, respectively. On rigid support and QB, the abdominal compartment contributed most of the V _CW in the supine (63.1% ± 11.4%) and prone (53.5% ± 13.1%) positions. V _CW was equally distributed between right and left sides. In the prone position we found a different chest wall volume distribution between pulmonary and abdominal rib cage (22.1% ± 8.6% and 24.4% ± 6.8, respectively) compared with the supine position (23.3% ± 9.3% and 13.6% ± 3.0%). © 2001 Biomedical Engineering Society. PAC01: 8763Lk, 8719Uv     

The Reliability of Arousal Threshold During Sleep

Thirty-five subjects from two independent studies were awakened at EEG-defined periods during the night with 1000 Hz ascending tone series. Awakenings were made five to eight times per night during stage 2, stage 4, or REM sleep over a series of nights in good and poor sleepers. Reliability was assessed within stage, within night, between stages, and between nights. Good and poor sleepers did not differ in either depth of sleep or reliability of arousal threshold and were thus pooled in the analyses. From night to night, the most consistency was seen in stage 4 (r=.74), although REM reliability (r?₁= .49) and stage 2 reliability (r?₁= .50 and r?₁= .69 in the two respective studies) estimates were also greater than zero. Early sleep onset and morning arousals were more variable. Reliability estimates on arousal thresholds taken within the same night for stage 2 were r= .64 and r?₁= .77 for the two studies and r= .96 for REM. The depth of sleep was not correlated with awake auditory threshold. It was concluded that five or six carefully placed arousals could give a good estimate of an individual's usual arousal threshold.     

Saccadic anomalies: vergence induces large departures from ball-and-socket behavior

The configuration of muscular forces, which maintains a given orientation of the eye, varies with vergence state. As a consequence, changes in vergence produce both static and dynamic violations of simple ball-and-socket behavior: during strong convergence, the entire eye is displaced temporally within its orbit at steady state by as much as 200 microns; and the axis of ocular rotation for small horizontal saccades is consistently displaced forward within the globe by an average of about 1 mm. These phenomena occur regardless of whether vergence is maintained by accommodation or by binocular disparity. Hence, systematic errors of as much as a full degree can arise in measurement of vergence movement, unless monitoring methods are used which are insensitive to translational motion. The observed displacement on the axis of rotation for saccades may be involved in subjective shrinkage of visual targets during convergence ("experimental micropsia ").