Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review.

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle. This article aims to summarize these approaches. Through database searches, we identified those studies related to objective muscle tone measurement in vivo, in situ. Based on them, we described existing methods and devices and compared their reliability. Furthermore, we presented an extensive list of the use of these methods in different fields of research. Although it is believed by some authors that palpation cannot be replaced by a mechanical device, several methods have already proved their utility in muscle biomechanical property diagnosis. There appear to be two issues preventing wider usage of these objective methods in clinical practice. Firstly, a high variability of their reliability, and secondly, a lack of valid mathematical models that would provide the observed mechanical characteristics with a clear physical significance and allow the results to be compared with each other.

Selected biomechanical aspects of the asymmetrical loading of the human postural system when riding the C1 speed canoe and their influence on the development of muscular imbalances.

OBJECTIVES: The main aim of this study was to analyse selected biomechanical aspects of the asymmetrical loading of the human postural system when riding the C1 speed canoe and their influence on the development of muscular imbalances. METHODS: 3D kinematic analysis of a simulated forward stroke of the canoeist in a pool with a counter-current (N = 9) and analysis of MRI data with selected individuals (N = 5), videoanalysis of actual paddling top athletes (N = 12), the kinesiological analysis of movement. RESULTS: Can be stated that when riding a C1 speed canoe the postural system is exposed to two types of asymmetric loading. In the first place, there is lateral asymmetry, which stems from the very nature of the one-sided paddling on this type of vessel. The canoeist has to compensate for the consequent instability by shifting the body's centre of gravity higher above the kneeling lower limb. This effect is achieved by the so-called pelvic lateralisation from the paddling side and by this side's skewing to the kneeling lower limb. Another asymmetry is connected to the forward-backward body movement and its time-dependent deviation from the neutral posture. A significant disproportion between generally fixation movements of the lower part of the body and phasic movements of the upper part of the body has been confirmed. These asymmetrical positions result in a significant unilateral overloading of the quadratus lumborum on the side of the supporting lower limb (side without the paddle), as well as an overloading of the spine straighteners in the lumbar area, in particular on the part of a supporting lower limb, and bilateral yet asymmetric overloading of m. iliopsoas, which in addition takes place in different isometries. The analysis of MRI data indicates that, during longitudinal training, lateral disproportion in the volume and intensity of postural system loading is the cause of different cross sections of the iliopsoas muscle and quadratus lumborum muscle on the side of the kneeling and supporting lower limbs. With both muscles, larger cross sections with a statistical significance level α = 0.05 and thus also strength on the side of the supporting lower limb can be expected. CONCLUSION: When canoeing on the C1, a significant unilateral overloading occurs with m. quadratus lumborum on the part of the supporting lower limb (side without paddle). Furthermore, spine straighteners in the lumbar area are overloaded, in particular in the part of the supporting lower limb. Last but not least however, the bilateral asymmetric overloading of m. iliopsoas occurs.

Influence of Selective Laser Melting Technology Process Parameters on Porosity and Hardness of AISI H13 Tool Steel: Statistical Approach.

The correct setting of laser beam parameters and scanning strategy for Selective Laser Melting (SLM) technology is a demanding process. Usually, numerous experimental procedures must be taken before the final strategy can be applied. The presented work deals with SLM technology and the impact of its technological parameters on the porosity and hardness of AISI H13 tool steel. In this study, we attempted to map the dependency of porosity and hardness of the tested tool steel on a broad spectrum of scanning speed-laser power combinations. Cubic samples were fabricated under parameters defined by full factorial DOE, and metallurgic specimens were prepared for measurement of the two studied quantities. The gathered data were finally analyzed, and phenomenological models were proposed. Analysis of the data revealed a minimal energy density of 100.3 J/mm3 was needed to obtain a dense structure with a satisfactory hardness level. Apart from this, the model may be used for approximation of non-tested combinations of input parameters.

The Mite Tyrophagus putrescentiae Hosts Population-Specific Microbiomes That Respond Weakly to Starvation.

The effect of short-term nutrient deprivation was studied in five populations of the mite Tyrophagus putrescentiae with different microbiomes. The fresh weight, nutrient status, respiration, and population growth of the mites were observed for the five mite population-scale samples. The starvation caused the larvae and nymphs to be eliminated, resulting in a significant increase in the fresh weight of starved adult specimens. Three populations were negatively influenced by starvation, and the starved specimens were characterized by a decrease in nutrient status, respiration, and population growth. One population was not influenced or was slightly influenced by starvation, which had no effect on population growth or nutrient contents but caused a significant decrease in respiration. One population was positively influenced by starvation; the population growth increased in starved specimens, and starvation had no effect on respiration. Although starvation altered the bacterial profiles of the microbiomes, these differences were much smaller than those between the populations. The bacterial profiles of Staphylococcus, Bacillus, Kocuria, Brevibacterium, and unidentified Micrococcaceae and Enterobacteriaceae increased in starved specimens, whereas those of Bartonella and Solitalea-like genera were reduced in the starved mite populations. The profiles of the intracellular symbiont Cardinium decreased in the starved specimens, and the Wolbachia profile changes were dependent on the mite population. In mite populations, when the symbionts were rare, their profiles varied stochastically. Correlations between changes in the profiles of the bacterial taxa and mite fitness parameters, including nutrient status (lipids, proteins, saccharides, and glycogen contents), mite population growth, and respiration, were observed. Although the microbiomes were resistant to the perturbations caused by nutrition deficiency, the responses of the mites differed in terms of their population growth, respiration, and nutrient status.

Estimating Realized Heritability in Panmictic Populations.

Narrow sense heritability [Formula: see text] is a key concept in quantitative genetics, as it expresses the proportion of the observed phenotypic variation that is transmissible from parents to offspring. [Formula: see text] determines the resemblance among relatives, and the rate of response to artificial and natural selection. Classical methods for estimating [Formula: see text] use random samples of individuals with known relatedness, as well as response to artificial selection, when it is called realized heritability. Here, we present a method for estimating realized [Formula: see text] based on a simple assessment of a random-mating population with no artificial manipulation of the population structure, and derive SE of the estimates. This method can be applied to arbitrary phenotypic segments of the population (for example, the top-ranking p parents and offspring), rather than random samples. It can thus be applied to nonpedigreed random mating populations, where relatedness is determined from molecular markers in the p selected parents and offspring, thus substantially saving on genotyping costs. Further, we assessed the method by stochastic simulations, and, as expected from the mathematical derivation, it provides unbiased estimates of [Formula: see text] We compared our approach to the regression and maximum-likelihood approaches utilizing Galton's dataset on human heights, and all three methods provided identical results.

Possibilities of objective identification of meniscoids in joint blocks of the axial system, by MRI and Transfer Vibration through the Spine.

OBJECTIVE: The aim of the study was to identify the meniscoids of the cervical spine using in-vivo MRI imaging and to determine their potential role in the development of functional joint blocks of the axial system (AS). Another objective was to find out how the articular blocks affect the rheological properties of the spine by the Transfer Vibration through the Spine (TVS) method. METHOD: In this study were used methods TVS and MRI. The study was conducted on a research file of 12 subjects and was conceived as a pilot one. RESULTS: It has been shown that the MRI method, in appropriate circumstances, enables the detection of changes in the size and shape of meniscoids in-vivo. On the basis of the investigations carried out, it can be assumed that several mechanisms are involved in the formation of functional joint blocks, and are not primarily caused by the incarceration of meniscoidal tissue. Using the TVS method, it has also been found that a functional articular blockade affects the rheological properties of the axial system, specifically reducing the damping capabilities of the particular spine segment. CONCLUSION: In the follow-up studies, it will be necessary to verify the theoretical interpretations on a larger statistical set.

Selected mechanical paremeters of women's hair in the Caucasian population.

OBJECTIVE: More parameters have been used for more detailed description of mechanical properties of human hair as a fibre than in analogous studies. All measured samples were taken from five different locations on the heads of 60 women of varied age. METHODS: For each hair, the diameter was determined optically and then the test in the Deform Type 2 testing machine was carried out. Deformation curves were obtained by testing 10 mm long samples up to the rupture point at constant temperature, humidity and constant crossbar speed of 2 mm/min. The curves were processed with software for the calculation of mechanical parameters of the hairs. This specialized software has been designed by us for that purpose. Resulting values were arranged into tables and figures. RESULTS: As far as hair cross-section is concerned, it has been found that for the European population it appears to be rather higher - 86 µm - than indicated in formerly published texts. The 56 µm mentioned in the work of other authors has been observed only utterly exceptionally, in 0.3 % of the population. All quantities studied (except extensibility) display moderate to strong positive skewness in comparison to Gauss distribution. The most marked skewness is seen in the resilience. At the same time, this quantity displays the highest value of non-Gaussian distribution. The elasticity module of 2.3±0.6 GPa is three times lower than the one reported by other authors, yet according to the fact published in our work - which shows unambiguously that the thinner the hair, the higher elasticity module it displays - the value of 7.2 GPa for the 56 µm thick hairs is comparable and it confirms the hypothesis that the cortex, which is responsible for the mechanical strength of the hair, is contained in a higher ratio in thinner hairs. This similarly applies to the ultimate strength; the linearity limit is hard to compare with literature, as it almost does not appear there. CONCLUSION: By measuring 886 samples from the heads of 60 adult women of European type, it was possible to ascertain the current norm for a larger number of mechanical parameters of the hairs. Further merit of this work is the fact that the hairs were taken systematically from five well-defined places of the studied heads in equal count, which is an aspect formerly published works do not respect and they do not present the location of sampling.

Molecular dynamics and IR spectroscopy in investigation of phase transitions in molecular crystal 4,4'-bis(11-hydroxy-1-undecyloxy)biphenyl.

Molecular dynamics (MD) simulations combined with temperature-dependent IR spectroscopic measurements were used to study phase transitions in molecular crystals of the mesogenic diol 4,4'-bis(11-hydroxy-1-undecyloxy)biphenyl. DSC measurements revealed four phase transitions in this molecular crystal at approximately 327.1 K, 389.8 K, 419.1 K and 431.9 K. Analysis of the dynamic trajectories at temperatures of 300 K, 360 K, 400 K and 480 K revealed changes in conformation of the mesogenic diol molecules and consequently changes in crystal packing and crystal structure in the temperature range 300-480 K and enabled us to understand the mechanism of the phase transitions.