Comparison between kinematic and ground reaction force techniques for determining gait events during treadmill walking at different walking speeds

This study involved a comparison of kinematics-based and ground reaction force (GRF)-based event detection methods. The objectives were (1) to assess the difference between the determination of gait events from GRF-based and kinematic/ultrasound-based techniques and (2) to determine the effects of gait speed on the agreement between the two techniques. At combined speeds, the average of the true difference was 2.6 ± 2.8 ms for heel strike and ?1.3 ± 2.4 ms for toe-off identification. A positive value indicated that GRF-based identification occurred before kinematics-based identification. The average of the true difference was ?3.9 ± 3.5 ms for the duration of stance; thus, the duration of stance as determined by the kinematics-based technique was shorter than that determined by GFR-based detection. Strong correlations (range 0.948–0.974) were found at all (slow, moderate, and fast) gait speeds. Near unity of slope of the linear regression line (range 0.955–1.008) was identified for the duration of stance between the two methods. Our results suggest that the agreement between the two event detection methods depended on gait speed, but the differences were small. The data determined using kinematic/ultrasound-based and GRF-based methods were comparable in healthy participants.     

基于非线性时间序列法研究人体步行稳定性

目的应用非线性时间序列分析方法,研究健康老年与青年志愿者的步行稳定性,为更全面评估人体的动态平衡、预测跌倒风险提供重要依据。方法应用VICON运动捕捉系统,采集肌骨系统健康志愿者(7名老年和10名青年)在不同步速(80%、100%1、20%自然步速)下的运动学数据,提取志愿者在30个连续步态周期中,第7颈椎和第10胸椎在前后和左右方向上的位移,以及下肢各关节屈曲伸展和外展内收运动角度,计算位移和运动角度变化的最大Lyapunov指数,比较分析老年与青年组之间步行稳定性差异,以及步速对人体步行稳定性影响。结果青年组步行稳定性优于老年组,并在某些运动节段呈现显著性差异(P<0.01);老年和青年的步行稳定性随步速增加而降低(P<0.05)。结论应用非线性时间序列分析方法中的最大Lyapunov指数,能有效并定量地评测人体步行中各运动节段的稳定性。     

金属植入物作用下腰椎后路3种融合方式的比较

背景：融合是腰椎减压椎弓根螺钉置入内固定后稳定运动节段的重要方式,经典的融合方式包括后外侧融合、后方椎间融合、后外侧融合并后方椎间融合。很多研究报道过几种融合方式的优势、技术要求、临床疗效和融合后并发症,但结论各异,很难明确最佳融合方式。 目的：比较后外侧融合、后方椎间融合、后外侧融合并后方椎间融合的疗效差异,以期寻求最佳融合方式。 方法：选择167例因退变性腰椎疾病行1个或2个节段融合,随访时间最短为3年的患者,分为3组,后外侧融合组62例,后方椎间融合组57组,后外侧融合+后方椎间融合组48例。通过目测类比评分、ODQ问卷和Kirkaldy-Willis 量表评价患者的腰痛、下肢疼痛和功能状况,并进行影像学评价,包括椎间盘高度、腰前凸、病变节段间角度、融合情况及融合后并发症。 结果与结论：最后1次随访结果表明,后外侧融合组患者中50例(80.7%)疗效优良,后方椎间融合组患者中50例(87.8%)疗效优良,后外侧融合+后方椎间融合组41例(85.5%)疗效优良,3组差异无显著性意义(P = 0.704)。3种融合方式都明显改善了椎间盘高度(P < 0.05),其中后外侧融合组椎间盘高度丢失最多,腰前凸和节段间角度明显增大,3种融合方式的节段间角度变化差异有显著性意义(P < 0.05)。最后1次随访时,3种融合方式的不融合率差异无显著性意义(P > 0.05)。治疗后并发症包括3例深部感染,4例暂时神经麻痹,1例永久神经麻痹,6例取骨处疼痛。提示3组融合方式在临床疗效和融合率方面无明显差异,后方椎间融合比后外侧融合能更好维持矢状面平衡。单纯后方椎间融合在缩短手术时间、减少失血量及避免取骨处疼痛方面有明显优势。     

Comparison of methods for identifying Staphylococcus and Micrococcus spp.

Three methods employed to distinguish staphylococci from micrococci were compared, using clinical and environmental strains. When these methods are used, misinterpretation of results, as well as erratic results, may occur, and suggestions for eliminating these problems are provided. The most sensitive test that combines ease of use and speed in obtaining results for distinguishing the two genera is the lysostaphin susceptibility test. Two other tests, facultatively anaerobic growth in semisolid thioglycolate agar and fermentation of dextrose, may also be used to distinguish these two genera, but results are often slow in developing, are subject to technical difficulties, and may lead to incorrect assignment of certain species of staphylococci and micrococci to their proper genera.     

Comparison of three methods for identification ofEnterobacteriaceae

This study compares the ability of three commercial overnight methods, API 20E, Minitek and Enteric-Tek, to accurately and completely identify 368 clinically isolatedEnterobacteriaceae without supplemental tests. Organisms includedEscherichia coli (54 strains),Shigella spp. (7),Edwardsiella tarda (1),Salmonella enteritidis (10),Citrobacter spp. (30),Klebsiella spp. (55),Enterobacter spp. (68),Hafnia alvei (2),Serratia spp. (33),Proteus spp. (64),Morganella morganii (24),Providencia spp. (18), andYersinia enterocolitica (2). Methods were those of the manufactures without supplemental tests. API 20E correctly identified 93.2 % of strains to species and 3.3 % to genus level only, with 3.0 % as part of a spectrum of identifications, and 0.5 % incorrect identifications. Minitek yielded 96.0 % correct identifications to species and 0.5 % to genus level only, with 2.5 % spectrum identifications, and 1.0 % incorrect identifications. Enteric-Tek correctly identified 97.0 % of strains to species level with 3.0 % spectrum identifications. API 20E identification of someSerratia andCitrobacter strains was to genus level only. Problem organisms for Minitek includedEnterobacter agglomerans andSerratia marcescens. A comparison of these three commercial methods shows that all three have the ability to identify most clinically isolatedEnterobacteriaceae without supplemental tests.     

Comparison of three typing methods for Pseudomonas aeruginosa

Fifty-seven independent isolates of Pseudomonas aeruginosa from blood specimens were typed with 3 different methods: ribotyping, random amplified polymorphic DNA (RAPD) typing, and pyocin typing. Ribotyping was performed by probing the rRNA genes of genomic DNA that was digested separately with 4 different restriction enzymes. Digestion of DNA from 57 P. aeruginosa isolates with BamHI, ClaI, EcoRI, and PstI produced 4, 4, 6, and 7 patterns, respectively. As a result, ribotyping classified the 57 isolates into 22 types. Six new ribotypes that had not been described previously were found. One BamHI, 1 ClaI, 2 EcoRI, and 2 PstI patterns were novel. RAPD typing was performed with two different polymerase chain reaction (PCR) primers (RAPD1 and RAPD2). Both primers classified the 57 isolates into 15 RAPD types and produced identical patterns. The pyocin typing method classified the 57 isolates into 10 types. According to the results obtained in this study, the ribotyping has a discriminatory index of 0.865, RAPD, 0.785, and pyocin typing, 0.676, respectively. The ribotyping method was the most effective among the 3 methods compared for typing P. aeruginosa isolates.     

Comparison of three methods for plasma fibrinogen.

Three plasma fibrinogen methods are presented based on (1) clottable protein assay by Biuret reagent, (2) measurement of clot absorbance and (3) thrombin time. These methods show good correlation and adequate precision on normal subjects as well as heparinized plasmas. The effects of interference owing to hemolysis, lipemia, bilirubin, heparin and fibrinogen degradation products are discussed briefly.     

Comparison of three methods for anaerobe identification.

In this study we evaluated the ability of three commercial methods, API 20A (Analytab Products, Plainview, N.Y.), Minitek (BBL Microbiology Systems, Cockeysville, Md.), and Anaerobe-Tek (Flow Laboratories, Inc., McLean, Va.), to accurately identify 165 recent clinical and 38 stock isolates of anaerobic bacteria without supplemental tests or gas-liquid chromatography. Strains included 89 Bacteroides spp., 12 fusobacteria, 10 gram-positive, nonsporing rods, 43 Clostridium spp., 15 Streptococcus intermedius, 18 peptococci, 6 peptostreptococci, 3 Staphylococcus saccharolyticus, and 7 Veillonella spp. The methods used were those of manufacturers, without supplemental tests. API 20A correctly identified 70.0% of strains to species and 6.4% to genus only, with 17.2% as part of a spectrum of identifications and 6.4% incorrect. Minitek, according to the current code book, yielded 69.5% correct identifications to species, 16.8% spectrum identifications, and 13.8% incorrect. Anaerobe-Tek correctly identified 64.0% of strains to species, 21.2% spectrum identifications, and 14.8% incorrect. Thirteen strains were misidentified by API 20A, 28 were misidentified by Minitek, and 30 were misidentified by Anaerobe-Tek. For laboratories without gas-liquid chromatography support and where identification of clinically significant Bacteroides fragilis and Clostridium perfringens is desired, any of the three systems would provide accurate information. For more extensive anaerobe identification, including the less frequently isolated, more unusual organisms, API 20A and Minitek are preferred at this time. All systems have identification schemes associated with a percentage of misidentifications, the most recently introduced Anaerobe-Tek system being associated with the highest error rate.     

正走和倒走的膝关节生物力学特征比较

目的 比较正走和倒走两种不同行走模式时膝关节的生物力学特征。方法 采用三维运动捕捉系统Vicon T40和测力台AMTI OR6-7采集并比较13名健康青年男性志愿者正走和倒走时的时间、空间、运动学和动力学参数。结果 与正走相比,倒走时的步速、步频和步幅均显著减小,跨步周期和支撑相所占百分比显著增加;在矢状面上,倒走时膝关节活动度、最大屈伸力矩较正走小;在冠状面上,倒走时膝关节内翻外展活动范围也较正走小,内翻力矩峰值在支撑早期较正走小,但在支撑晚期较正走大;地面反作用力在支撑早期较正走大,但在支撑晚期较正走小。结论 倒走和正走膝关节生物力学特征差异明显。与正走相比倒走在支撑相早期能减轻膝关节内侧间室的负荷,而倒走在支撑相晚期对膝关节负荷的影响则尚须进一步研究。     

A quantitative gait assessment method based on energy exchange analysis during walking: a normal gait study

In this paper a gait efficiency assessment method, Gait Energy Efficiency Index (GEEI), which can be used in evaluation of the progress of the rehabilitation process in disabled persons, is proposed and described. The method is based on calculation of cross correlation between normalized time courses of kinetic and potential energy of the body's centre of mass (COM). We hypothesized that GEEI in energetically optimal normal walking should be high and invariable of gait speed. The method was tested on twelve healthy subjects walking at three different speeds and contrasted to five established gait energy consumption assessment methods. The results showed that GEEI in normal walking is close to 1 regardless of walking speed.     

Comparison of three methods for genotyping of prothrombotic polymorphisms

Several methods have been developed to detect common prothrombotic mutations, including factor V Leiden (G1691), prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677C. In this study, we compared the accuracy of three different molecular techniques, i.e.: (1) restriction enzyme digestion (RFLP), (2) real time with hybridization probes and final melting curve (Fluorescence Resonance Energy Transfer, FRET), and (3) real time with hydrolysis probes (TaqMan^®). Sequencing was used as the reference standard. Our data showed that RFLPs analysis for the detection of prothrombotic mutations, albeit easy-to-perform, had a limited reliability for assessing correct genotypes. FRET analysis displayed higher resolution than RFLPs. Additionally, FRET analysis was faster and less tedious than sequencing.     

A quantitative gait assessment method based on energy exchange analysis during walking: a normal gait study

In this paper a gait efficiency assessment method, Gait Energy Efficiency Index (GEEI), which can be used in evaluation of the progress of the rehabilitation process in disabled persons, is proposed and described. The method is based on calculation of cross correlation between normalized time courses of kinetic and potential energy of the body's centre of mass (COM). We hypothesized that GEEI in energetically optimal normal walking should be high and invariable of gait speed. The method was tested on twelve healthy subjects walking at three different speeds and contrasted to five established gait energy consumption assessment methods. The results showed that GEEI in normal walking is close to 1 regardless of walking speed.     

Comparison of three methods for the estimation of plasma antithrombin.

Plasma antithrombin levels were measured by clotting, immunological, and amidolytic methods on two groups of subjects: 20 normal individuals and nine patients studied serially post-operatively (hip replacement). The postoperative patients were observed for the emergence of deep-vein thrombosis using 125I-fibrinogen uptake measurements (FUT). The three methods gave similar ranges for the normal subjects, were reproducible (cv less than 5%), and detected early postoperative reduction of antithrombin levels. All three methods failed to show any significant differences in preoperative antithrombin levels between the positive and negative FUT groups. Correlation studies were performed on the pooled data from the normal and postoperative group (range 60-130% of normal; 100 samples). The best correlation (r = 0.75; P less than 0.01) was achieved with the chromogenic kit assay method versus the Mancini immunoassay technique. The thrombin agarose (total antithrombin) gel diffusion technique correlated less well with the chromogenic (r = 0.65; P less than 0.01) and Mancini immunoassay (r = 0.45; P less than 0.01) methods. It is concluded that the chromogenic kit method gives a rapid, reproducible, and specific measurement of antithrombin III. The thrombin agarose diffusion method, though not specific for antithrombin III, is a cheap and simple method to perform. The potential of the three methods for detecting the prethrombotic stage and early thrombosis is discussed.     

Comparison of three serological methods for the detection of hepatitis-associated antigen

Serum hepatitis (Australia) antigen in the sera of hepatitis patients and carriers can be detected in one and a half to three hours by crossover electrophoresis. The method is more sensitive than the immunodiffusion technique commonly employed in this field. It is of the same order of sensitivity as complement fixation but is less complicated.Crossover electrophoresis is thus the method of choice for the rapid screening of sera for hepatitis antigen; complement fixation may be used for quantitative determination of antigen in positive cases.     

三种测序DNA模板制备方法的比较○

背景：DNA模板质量对DNA序列测定起着至关重要的作用。 目的：为基因组DNA或甲基化DNA测序寻找一种经济,简便的方法。 方法：分别采用96管集合板及96孔板提取质粒,并且针对质粒设计一对包含目的片段的引物,扩增后纯化PCR产物,通过以上3种方法制备DNA测序模板进行测序。 结果与结论：实验所采用的3种方法对于基因组DNA测序效果无差异(P > 0.05)。对于甲基化DNA测序效果,96管集合板法优于其他2种方法(P < 0.05)。说明3种方法均适用于基因组DNA的测序,而96管集合板法更适用于甲基化DNA的测序。      

Comparison of two methods of identifying satellite associations in man

Two methods of identifying satellite associations were compared in ten healthy blood donors. When the conventional Giesma staining method was used, 31% fewer 3-chromosome associations, 50% fewer 4- and 5-chromosome associations, and 66.6% fewer 6-chromosome associations were identified than by staining with ammoniacal silver. Meanwhile, 10% more 2-chromosome associations were identified, on account of the predominance of small associations. Staining with silver when used to detect intersatellite associations revealed acrocentric chromosomes in close juxtaposition and mutually oriented, but with no connections between the satellites. In Giemsa preparations these chromosomes are regarded as associated, with a consequent increase in the number of associations. In the traditional Giemsa staining method neither error is corrected. Identification of associations based on the presence of intersatellite connections after staining with silver is free from this disadvantages.Academic Group of Academician of the Academy of Medical Sciences of the USSR, A. I. Nesterov. (Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Nesterov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 9, pp. 371–374, September, 1978.     

Spatial parameters of walking gait and footedness

Objective: The present study was undertaken to assess whether footedness has effects on selected spatial and angular parameters of able-bodied gait by evaluating footprints of young adults.

Subjects and methods: A total of 112 males and 93 females were selected from among students and staff members of the University of Malawi using a simple random sampling method. Footedness of subjects was assessed by the Waterloo Footedness Questionnaire Revised. Gait at natural speed was recorded using the footprint method. The following spatial parameters of gait were derived from the inked footprint sequences of subjects: step and stride lengths, gait angle and base of gait. The anthropometric measurements taken were weight, height, leg and foot length, foot breadth, shoulder width, and hip and waist circumferences.

Results: The prevalence of right-, left- and mix-footedness in the whole sample of young Malawian adults was 81%, 8.3% and 10.7%, respectively. One-way analysis of variance did not reveal a statistically significant difference between footedness categories in the mean values of anthropometric measurements (p?>?0.05 for all variables). Gender differences in step and stride length values were not statistically significant. Correction of these variables for stature did not change the trend. Males had significantly broader steps than females. Normalized values of base of gait had similar gender difference. The group means of step length and normalized step length of the right and left feet were similar, for males and females. There was a significant side difference in the gait angle in both gender groups of volunteers with higher mean values on the left side compared to the right one (t?=?2.64, p?<?0.05 for males, and t?=?2.78, p?<?0.05 for females). One-way analysis of variance did not demonstrate significant difference between footedness categories in the mean values of step length, gait angle, bilateral differences in step length and gait angle, stride length, gait base and normalized gait variables of male and female volunteers (p?>?0.05 for all variables).

Conclusions: The present study demonstrated that footedness does not affect spatial and angular parameters of walking gait.     

Spatial parameters of walking gait and footedness

OBJECTIVE: The present study was undertaken to assess whether footedness has effects on selected spatial and angular parameters of able-bodied gait by evaluating footprints of young adults. SUBJECTS AND METHODS: A total of 112 males and 93 females were selected from among students and staff members of the University of Malawi using a simple random sampling method. Footedness of subjects was assessed by the Waterloo Footedness Questionnaire Revised. Gait at natural speed was recorded using the footprint method. The following spatial parameters of gait were derived from the inked footprint sequences of subjects: step and stride lengths, gait angle and base of gait. The anthropometric measurements taken were weight, height, leg and foot length, foot breadth, shoulder width, and hip and waist circumferences. RESULTS: The prevalence of right-, left- and mix-footedness in the whole sample of young Malawian adults was 81%, 8.3% and 10.7%, respectively. One-way analysis of variance did not reveal a statistically significant difference between footedness categories in the mean values of anthropometric measurements (p > 0.05 for all variables). Gender differences in step and stride length values were not statistically significant. Correction of these variables for stature did not change the trend. Males had significantly broader steps than females. Normalized values of base of gait had similar gender difference. The group means of step length and normalized step length of the right and left feet were similar, for males and females. There was a significant side difference in the gait angle in both gender groups of volunteers with higher mean values on the left side compared to the right one (t = 2.64, p < 0.05 for males, and t = 2.78, p < 0.05 for females). One-way analysis of variance did not demonstrate significant difference between footedness categories in the mean values of step length, gait angle, bilateral differences in step length and gait angle, stride length, gait base and normalized gait variables of male and female volunteers (p > 0.05 for all variables). CONCLUSIONS: The present study demonstrated that footedness does not affect spatial and angular parameters of walking gait.     

Comparison of three simple methods for the assessment of `free'' thyroid hormone

A dialysis method for estimating ;free' thyroxine is compared with two indirect methods using the uptake of triiodothyronine by the red cells and by a Sephadex column. The three methods give results which correlate well and the Sephadex method is the simplest.The theoretical basis of such tests and their role in the assessment of thyroid status is briefly discussed.