Determination of biomechanical characteristics of restrictive adhesions and of functional impairment after flexor tendon surgery: a methodological study of rabbits.

Formation of restrictive adhesions is one of the main obstacles in rehabilitation following hand surgery. Most experimental work, however, involves only a macroscopic and/or histologic evaluation of the amount of adhesions, and their functional characteristics are poorly described. The aim of this study was to develop an experimental technique for characterization of the biomechanical properties of the finger-tendon unit. An instrument was developed for continuous and simultaneous recording of tensile load, tendon excursion and angular rotation in the distal interphalangeal joint of rabbit digits. Utilizing this instrument, it was revealed that the first 50 degrees of flexion required virtually no tensile load either in unoperated digits or immediately after tenorrhaphy. Thereafter, the load required to obtain further flexion was progressively increased. The strength of adhesions, determined 2 weeks after tenorrhaphy, was best expressed as the maximum tensile load recorded before 50 degrees of flexion was reached. This measurement could also be used to register the strength of the tendon repair and to detect partial tendon rupture during the measurement. The technique allows both adequate measurements of the strength of the adhesions and of the tendon gliding ability after flexor tendon surgery.     

Planning movements in a simple redundant task

There are infinitely many different combinations of arm postures which will place the hand at the same point in space. Given this abundance, how is one configuration chosen over another? Two main hypotheses have been proposed to solve this problem. Postural models suggest that the posture adopted is purely determined by the desired hand position (known as Donders' law). Transport models suggest that the adopted posture depends on where the hand has moved from. A specific transport model, the minimum work model, has been proposed in which the adopted posture is the one that minimizes the amount of work required to move the hand to the new location. The postural model predicts that the posture will be independent of where the hand has moved from, whereas the transport models predict that the posture will depend on the previous posture. We have devised a simple redundant task-touching a target bar using a hand-held virtual stick-to examine these models. The results show that neither model alone can account for the data. We propose a control planning strategy in which there is a combined cost function that has both a postural term as well as a transport term.     

Imaging modalities in hand osteoarthritis--and perspectives of conventional radiography, magnetic resonance imaging, and ultrasonography

Hand osteoarthritis (OA) is very frequent in middle-aged and older women and men in the general population. Currently, owing to high feasibility and low costs, conventional radiography (CR) is the method of choice for evaluation of hand OA. CR provides a two-dimensional picture of bony changes, such as osteophytes, erosions, cysts, and sclerosis, and joint space narrowing as an indirect measure of cartilage loss. There are several standardized scoring methods for evaluation of radiographic hand OA. The scales have shown similar reliability, validity, and sensitivity to change, and no conclusion about the preferred instrument has been drawn. Patients with hand OA may experience pain, stiffness, and physical disability, but the associations between radiographic findings and clinical symptoms are weak to moderate and vary across studies. OA is, indeed, recognized to involve the whole joint, and modern imaging techniques such as ultrasound (US) and magnetic resonance imaging (MRI) could be valuable tools for better evaluation of hand OA. Standardized scoring methods have been proposed for both modalities. Several studies have examined the validity of US features in hand OA, whereas knowledge of the validity of MRI is more limited. However, both synovitis (detected by either US or MRI) and MRI-defined bone marrow lesions have been associated with pain, indicating that treatment of inflammation is important for pain management in hand OA. Both US and MRI have shown better sensitivity than CR in detection of erosions, and this may indicate that erosive hand OA may be more common than previously thought.     

Imaging modalities in hand osteoarthritis - status and perspectives of conventional radiography, magnetic resonance imaging, and ultrasonography

Hand osteoarthritis (OA) is very frequent in middle-aged and older women and men in the general population. Currently, owing to high feasibility and low costs, conventional radiography (CR) is the method of choice for evaluation of hand OA. CR provides a two-dimensional picture of bony changes, such as osteophytes, erosions, cysts, and sclerosis, and joint space narrowing as an indirect measure of cartilage loss. There are several standardized scoring methods for evaluation of radiographic hand OA. The scales have shown similar reliability, validity, and sensitivity to change, and no conclusion about the preferred instrument has been drawn. Patients with hand OA may experience pain, stiffness, and physical disability, but the associations between radiographic findings and clinical symptoms are weak to moderate and vary across studies. OA is, indeed, recognized to involve the whole joint, and modern imaging techniques such as ultrasound (US) and magnetic resonance imaging (MRI) could be valuable tools for better evaluation of hand OA. Standardized scoring methods have been proposed for both modalities. Several studies have examined the validity of US features in hand OA, whereas knowledge of the validity of MRI is more limited. However, both synovitis (detected by either US or MRI) and MRI-defined bone marrow lesions have been associated with pain, indicating that treatment of inflammation is important for pain management in hand OA. Both US and MRI have shown better sensitivity than CR in detection of erosions, and this may indicate that erosive hand OA may be more common than previously thought.     

Changes in the lymphoid tissue and in the level of corticosteroids in staphylococcal intoxication and infection]

A complex quantitative study of changes of proliferative processes in lymphatic vessels on the one hand and changes of the level of corticosteroids in the peripheral blood in staphylococcal intoxication and infection in the same rats on the other hand has been carried out. In the work H3-thymidine has been used. The comparison of the obtained morphological data with the dynamics of the change in the corticosteroid level shows that the decay of lymphocytes, the devastating of light centers and the cortical substance of lymph nodes, an abrupt lowering of the amount of DNA-synthesizing and mitotically dividing cells take place in the period associated with a release of a great amount of corticosteroids into the blood. The drop of their level to control values goes in parallel with increasing the amount of DNA-synthesizing and mitotically dividing cells. The obtained data suggest that the leading role in those changes of the lympoid tissue which had been described by a number of authors in infectional processes is played by corticosteroids.     

An analysis of the work and tasks of the microbiology laboratory at a multidisciplinary research institute

The comparative analysis of the work of 3 groups of microbiologists at a multiple-discipline clinical research institute has permitted the development of the method for the evaluation of the work of researchers in the microbiological laboratory. The volume of investigations carried out in the laboratory, the relative significance of individual samples of clinical material, the degree of contamination of the samples under study, the level of the identification of microbes and the analysis of the data obtained in the course of investigations have been used as evaluation criteria. The method may be used for the objective quantitative evaluation of the work and the level of professional training of individual researchers, as well as for the calculation of expenditures in materials and time, necessary for performing investigations. According to the data of the analysis carried out by the authors with the use of the proposed method, the work of scientific-practical groups at the institutions of this category holds the greatest promise.     

Antifungal susceptibility testing: Recent findings and experience

The current status of antifungal susceptibility tests is very much in flux. There is ample evidence that current testing of fungi is at this point poorly standardized, and therefore the results from such tests are difficult to apply to patient management. On the other hand, there is now considerable interest in collaborative efforts to change this situation and all evidence to date indicates that standardization is a reasonable and clearly achievable goal. In the NCCLS Subcommittee Report, ²⁹ several steps were proposed to reach that objective. Among others, they include: 1) Establishing a panel of fungal isolates to be used in further studies; 2) Establish performance standards for a single media that might be used to test all known classes of antifungal agents; and 3) Determine and correct the sources of error that result in variability of the broth dilution method.Now that the problem has been more sharply defined, work to eliminate interlaboratory variability and to determine test correlation with treatment results should proceed. Hopefully work during the next few years will result in antifungal tests that are just as useful as today's tests for antibacterial agents.     

Surface EMG in advanced hand prosthetics

One of the major problems when dealing with highly dexterous, active hand prostheses is their control by the patient wearing them. With the advances in mechatronics, building prosthetic hands with multiple active degrees of freedom is realisable, but actively controlling the position and especially the exerted force of each finger cannot yet be done naturally. This paper deals with advanced robotic hand control via surface electromyography. Building upon recent results, we show that machine learning, together with a simple downsampling algorithm, can be effectively used to control on-line, in real time, finger position as well as finger force of a highly dexterous robotic hand. The system determines the type of grasp a human subject is willing to use, and the required amount of force involved, with a high degree of accuracy. This represents a remarkable improvement with respect to the state-of-the-art of feed-forward control of dexterous mechanical hands, and opens up a scenario in which amputees will be able to control hand prostheses in a much finer way than it has so far been possible. This work is partially supported by the project NEURObotics, FP6-IST-001917.     

Automated hexahedral meshing of anatomic structures using deformable registration

This work introduces a novel method of automating the process of patient-specific finite element (FE) model development using a mapped mesh technique. The objective is to map a predefined mesh (template) of high quality directly onto a new bony surface (target) definition, thereby yielding a similar mesh with minimal user interaction. To bring the template mesh into correspondence with the target surface, a deformable registration technique based on the FE method has been adopted. The procedure has been made hierarchical allowing several levels of mesh refinement to be used, thus reducing the time required to achieve a solution. Our initial efforts have focused on the phalanx bones of the human hand. Mesh quality metrics, such as element volume and distortion were evaluated. Furthermore, the distance between the target surface and the final mapped mesh were measured. The results have satisfactorily proven the applicability of the proposed method.     

From high-resolution CT data to finite element models: development of an integrated modular framework

This work introduces a novel method of automating the process of patient-specific finite element (FE) model development using a mapped mesh technique. The objective is to map a predefined mesh (template) of high quality directly onto a new bony surface (target) definition, thereby yielding a similar mesh with minimal user interaction. To bring the template mesh into correspondence with the target surface, a deformable registration technique based on the FE method has been adopted. The procedure has been made hierarchical allowing several levels of mesh refinement to be used, thus reducing the time required to achieve a solution. Our initial efforts have focused on the phalanx bones of the human hand. Mesh quality metrics, such as element volume and distortion were evaluated. Furthermore, the distance between the target surface and the final mapped mesh were measured. The results have satisfactorily proven the applicability of the proposed method.     

A behavior-based inverse kinematics algorithm to predict arm prehension postures for computer-aided ergonomic evaluation.

In this paper, the computational problem of inverse kinematics of arm prehension movements was investigated. How motions of each joint involved in arm movements can be used to control the end-effector (hand) position and orientation was first examined. It is shown that the inverse kinematics problem due to the kinematic redundancy in joint space is ill-posed only at the control of hand orientation but not at the control of hand position. Based upon this analysis, a previously proposed inverse kinematics algorithm (Wang et Verriest, 1998a) to predict arm reach postures was extended to a seven-DOF arm model to predict arm prehension postures using a separate control of hand position and orientation. The algorithm can be either in rule-based form or by optimization through appropriate choice of weight coefficients. Compared to the algebraic inverse kinematics algorithm, the proposed algorithm can handle the non-linearity of joint limits in a straightforward way. In addition, no matrix inverse calculation is needed, thus avoiding the stability and convergence problems often occurring near a singularity of the Jacobian. Since an end-effector motion-oriented method is used to describe joint movements, observed behaviors of arm movements can be easily implemented in the algorithm. The proposed algorithm provides a general frame for arm postural control and can be used as an efficient postural manipulation tool for computer-aided ergonomic evaluation.     

Muscular mechanical energy expenditure as a process for detecting potential risks in manual materials handling

The problem of injuries in manual materials handling remains a big concern in industrialized countries. It has become imperative in occupational biomechanics to extend the analyses to all pertinent factors involved in working tasks and to adopt an experimental approach leading to the understanding of the relative demands imposed simultaneously on all body joints. The evaluation of joint muscular work and the processes of energy generation, absorption and transfer appears promising as a tool in the detection of risk factors in working tasks. The present study consisted of evaluating two tasks (lifting and lowering) performed at five different heights (from 15 to 185 cm) with five different loads (from 3.3 to 22.0 kg). The subjects were eight experienced workers from a food product warehouse. Cinematography techniques and two AMTI force platforms were used to collect the data. Dynamic and planar segmental analyses were performed to calculate the net muscular moments at the joints, and work was calculated from the integration of muscular power. Factorial analyses of variance with repeated measures were performed on the dependent variables to evaluate the main effects of tasks, loads, and heights (for lifting and for lowering) and the interactions. The results revealed the adoption of different movement strategies in the handling of heavier loads. In the first, a larger emphasis of energy transfer and movement economy; in the second, a reduction in the relative contribution of the shoulders to the detriment of an increased participation of the lower back and hips was found. The comparison between lifting and lowering tasks indicated that lifting was only slightly more demanding than lowering for maximum muscular moments (about 15%) but much more so for mechanical work (about 40%); however, the nature of the efforts in eccentric contractions suggests that the lowering of heavy loads may be risky. Finally, the results revealed the deviation of height of handling from the waist level to be a significant factor. Handling at lower heights was considerably more demanding but the work was shared by several joints, mainly by the hips and lower back (about 70%); on the other hand, in handling above the waist, the work efforts were concentrated on the upper limbs (about 80%). In most cases, the participation of lower limbs was minimal and some movement strategies are suggested for future research.     

Kinematic features of wheelchair propulsion

Three male paraplegics volunteered to push their wheelchairs on a motor driven treadmill, for a total of 80 min each, at a work rate of 60-65% of their VO2 maximum, determined on an earlier test session. At 20 min intervals 16 mm high-speed film of the subjects was taken for three consecutive push cycles. The digitized film was used to compute the angular kinematics of the shoulder and elbow joints, the variations in the position of the trunk (as measured by a marker on the neck) and hand relative to the axle of the rear wheel. There were no intrasubject variations over the 80 min testing period for any of the recorded variables. This was interpreted as implying that at that work rate, fatigue was not exhibited as variations in the kinematics of movement. There were considerable differences between the style of one subject when compared to the other two over all the trials of each subject. This variation in style was most obvious in subject number PT who had a pumping style of push and recovery whereas subjects CA and GW employed a more continuous circular motion. The differences in the amount of forward lean of each subject were related to residual muscle strength. The discussion centered on the influence of the different styles on performance.     

The evaluation of horizontal resistance of winter wheats by the ‘center pivot’ method

Summary Twenty bread wheat varieties were sown in forty meter long plots and infected with a mixture of three races of stem rust (14, 34, 311) in the Center-pivot design. The epidemic's development and its effect on yield (factors) were studied in an experiment.With the Center-pivot method we modelled the natural processes without chemicals. The epidemic's development and the processes connected with it can be studied quantitatively as well as by subjective evaluation.Some of the studied genotypes were quickly infected and others slowly. The date of infection proved to be especially important to the amount of yield decrease.However, a quick spread of the epidemic does not inevitably lead to a decrease of yield and 1000-grain-weight for every genotype.Vertical resistance has qualitative features. On the other hand, there is only a quantitative difference between field resistant and tolerant genotypes, and between horizontally resistant and susceptible ones. The tolerant genotypes cannot limit the spread of the epidemic, but they can limit the degree of damage, and so their yields and 1000-grain-weights are essentially uninfluenced. The field resistant genotypes slow down the epidemic's development, and therefore their yields and 1000-grain-weights decrease less. This fact makes possible their separation in two steps, first on the basis of epidemic development, and then by measuring the decrease of yield and 1000-grainweight.Tolerance and field resistance are supposed to be inherited olygenically. Consequently, breeding for horizontal resistance should work with basically different methods than those previously used for race-specific resistance.     

Efficient Nash Equilibrium Resource Allocation Based on Game Theory Mechanism in Cloud Computing by Using Auction

One of the most complex issues in the cloud computing environment is the problem of resource allocation so that, on one hand, the cloud provider expects the most profitability and, on the other hand, users also expect to have the best resources at their disposal considering the budget constraints and time. In most previous work conducted, heuristic and evolutionary approaches have been used to solve this problem. Nevertheless, since the nature of this environment is based on economic methods, using such methods can decrease response time and reducing the complexity of the problem. In this paper, an auction-based method is proposed which determines the auction winner by applying game theory mechanism and holding a repetitive game with incomplete information in a non-cooperative environment. In this method, users calculate suitable price bid with their objective function during several round and repetitions and send it to the auctioneer; and the auctioneer chooses the winning player based the suggested utility function. In the proposed method, the end point of the game is the Nash equilibrium point where players are no longer inclined to alter their bid for that resource and the final bid also satisfies the auctioneer’s utility function. To prove the response space convexity, the Lagrange method is used and the proposed model is simulated in the cloudsim and the results are compared with previous work. At the end, it is concluded that this method converges to a response in a shorter time, provides the lowest service level agreement violations and the most utility to the provider.     

Assessment of cardiotocographs

In recent years advances in medical electronic equipment for monitoring, diagnosis and treatment of patients have led to a large increase in the number and variety of instrumentation available to the medical profession. There is a considerable amount of duplication of equipment and in the absence of readily available information buyers are unlikely to make informed decisions about the ideal instrument for their particular circumstances. One method of increasing the users' awareness is a comparative, independent assessment of equipment, with the results disseminated to the interested parties. This paper describes the essential qualities of cardiotocographs: how they are assessed as part of the UK Department of Health's evaluation programme and the measures to inform users of the latest evaluation information.     

Flash fluorometer made from off-the-shelf photographic equipment to measure tissue levels of fluorescein

A device to measure fluorescein in tissue has been constructed from standard photographic equipment--an electronic strobe and a flashmeter both covered with interference filters. The instrument works well in the light and need not touch the area being measured, an advantage over existing fluorometers. The instrument has been used to measure the amount of dye in flaps in rats, pigs, and three humans. The results revealed that the amount of dye in a freshly made flap was rarely as much as in normal skin, and skin with less than 20 percent of the dye of control areas usually sloughed, although there were exceptions. In the future the instrument will be improved, and its readings will be compared to those obtained from radioactive microspheres, the present "gold standard" of techniques to measure vascularity. The instrument can be used to estimate the blood supply to any tissue and seems to be as reliable as the dermofluorometers already on the market.     

Simple techniques for freeze clamping and for cutting and milling of frozen tissue at low temperature for the purpose of two- or three-dimensional metabolic studies in vivo

A technique is described for freeze-clamping of parenchymal tissue (e.g., liver) which causes the tissue to be rigidly fixed to an aluminium cup in the frozen state with a well-defined, reproducible orientation of the tissue as well as a minimum of morphological distortion of the major part of the sample. Furthermore, three instruments for low-temperature cutting or milling of the frozen sample for the purpose of two- or three-dimensional metabolic studies are described. The cutting and milling instruments work according to the principle of ordinary workshop machines for steel work. The frozen sample fixed in the aluminium cup may be mounted in the milling instrument and cut at the temperature of liquid nitrogen with high precision; e.g., one instrument may be adjusted to mill off tissue layers of a thickness of only 20 μm. Thermocouple readings from the frozen sample suggest that the milling process does not cause significant heating of the sample. This is further supported by the fact that the amount of labile metabolites, ATP, ADP, AMP, lactate, and pyruvate, is unaffected by the milling process.     

Method and Application for Dynamic Comprehensive Evaluation with Subjective and Objective Information

In an effort to deal with more complicated evaluation situations, scientists have focused their efforts on dynamic comprehensive evaluation research. How to make full use of the subjective and objective information has become one of the noteworthy content. In this paper, a dynamic comprehensive evaluation method with subjective and objective information is proposed. We use the combination weighting method to determine the index weight. Analysis hierarchy process method is applied to dispose the subjective information, and criteria importance through intercriteria correlation method is used to handle the objective information. And for the time weight determination, we consider both time distance and information size to embody the principle of esteeming the present over the past. And then the linear weighted average model is constructed to make the evaluation process more practicable. Finally, an example is presented to illustrate the effectiveness of this method. Overall, the results suggest that the proposed method is reasonable and effective.