Neutral Zones Research Articles

Four Weeks of Balance Training does not Affect Ankle Joint Stiffness in Subjects with Unilateral Chronic Ankle Instability.

Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with chronic ankle instability (CAI) but the biomechanical pathways underlying the clinical outcomes are still unknown. This study was conducted to determine if a 4-week balance training intervention can alter the mechanical characteristics in ankles with CAI. Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n = 11, 35.1 ± 9.3 years) or intervention (n = 11, 33.5 ± 6.6 years) group. Subjects in the intervention group were trained on the affected limb with static and dynamic components using a Biodex balance stability system for 4-weeks. The ankle joint stiffness and neutral zone in inversion and eversion directions on the involved and uninvolved limbs was measured at baseline and post-intervention using a dynamometer. At baseline, the mean values of the inversion stiffness (0.69 ± 0.37 Nm/degree) in the involved ankle was significantly lower (p < 0.011, 95% CI [0.563, 0.544]) than that of uninvolved contralateral ankle (0.99 ± 0.41 Nm/degree). With the available sample size, the eversion stiffness, inversion neutral zone, and eversion neutral zone were not found to be significantly different between the involved and uninvolved contralateral ankles. The 4-week balance training intervention failed to show any significant effect on the passive ankle stiffness and neutral zones in inversion and eversion. Decreased inversion stiffness in the involved chronic unstable ankle was found that of uninvolved contralateral ankle. The 4-week balance training program intervention was ineffective in altering the mechanical characteristics of ankles with CAI. Randomized controlled clinical trial; Level of evidence, 1.

Ion current rectification influenced by length and location of surface charge in fluidic unipolar conical nanopores

Ion current rectification (ICR) in a fluidic unipolar nanopore consisting of a charged zone and one or two neutral zones has been investigated. The effect of length and location of surface charge on its walls on ion transport in a fluidic unipolar nanopore have been studied. The ICR can be reversed by keeping a neutral zone towards the tip instead of charged zone in a nanopore. A longer neutral zone towards the base of the nanopore enhances ICR and a longer charged zone towards the base enhances reverse rectification. The effect of asymmetry of the pore on ICR has also been analyzed by comparing results with nanochannel.

The Threats and Challenges of a Multipolar World: A Ukraine Crisis Case Study

IntroductionThe crisis in and around Ukraine has clearly demonstrated that the world has changed. This is not news for the most observant politicians and researchers. The changes accumulated slowly, and many of the consequences were predictable.

Methodology for Multiobjective Optimization of the AC Railway Power Supply System

Electrical dimensioning design in a railway infrastructure has high complexity and is strongly nonlinear. There are several parameters and constraints to take into account. The presented methodology is working to improve the decision making about the design, hence developing an expert system. The final set of possible solutions that the method is achieved is based on a pair of main objectives. On the one hand are installation costs, environmental impact, main electrical components costs such as catenary, traction substations, neutral zones, and the difficulty to connect substation to general electric grid. On the other hand are exploitation costs, such as maintenance costs and energy loss depending on the dimensioning design. A specific line discretization has been developed in order to distribute the critical zones along the line. Integration of a multiobjective genetic algorithm (NSGA-II), hence the code of the genotype, is another highlight. Electrical analysis, railway systems using single alternate current (1 × 25), and a simplification due to the search of the highest peaks of power demanded by the trains during simulations help to minimize the quantity of studies. Every simulation is possible by using a railway simulator, Hamlet, which provides modules such as infrastructure, rolling stock, signaling, and electrical. Designers have the possibility to analyze several scenarios with different railway exploitation critical levels, analyze electrical degraded situations, and finally obtain an optimal Pareto Front, reaching a powerful methodology to help in the electrical dimensioning design.

Biomechanical Evaluation of Capsulotomy and Capsular Repair in the Hip

Objectives:The use of hip arthroscopy has increased over recent years to treat various forms of hip pathologies including femoroacetabular impingement. While a capsulotomy facilitates adequate visualization and access for diagnostic and interventional purposes, the current literature remains divided over the use of routine capsular closure to address the iatrogenic instability that may be induced by an excessive or unclosed capsulotomy. The purpose of this biomechanical study was to determine if hip capsulotomy creates significant alterations in rotational range of motion and stability measures. Additionally, does a capsular repair return these variables to normal?Methods:Eight fresh-frozen cadaveric hip specimens consisting of the hemipelvis, femur, and overlying soft tissues were used for this study. All specimens were screened by computed tomography (CT) to assess for the absence of significant bony pathology. Each hip was then tested under torsional loads of 6 N·m applied via a pulley system in conjunction with a vertical force exerted by a servohydraulic frame. Conditions tested were as follows: 1) neutral flexion with the capsule intact 2) neutral flexion with a 4 cm inter-portal capsulotomy 3) neutral flexion with a 6 cm inter-portal capsulotomy 4) neutral flexion with capsulotomy repair. Soft tissue was retained during all interventions. Range of motion (from external to internal rotation), hysteresis area, and neutral zones were the outcome measures for stability obtained in each condition.Results:While the data demonstrated a positive and statistically significant correlation between the sizes of the capsulotomy and measures of joint instability (range of motion (ROM), hysteresis area, and neutral zone), no significant differences were seen between the intact and repaired hips with regards to such measures (Table). Larger size capsulotomies were accompanied by significant increases in all three measures of joint instability while the repair effectively restored the capsule to conditions similar to its intact state.Conclusion:To the best of the authors’ knowledge, this study is the first to demonstrate the biomechanical consequences of sequentially increasing capsulotomy incisions and their repair on a hip joint that still contains its surrounding soft tissue. The results of this study not only confirm the notion of introducing iatrogenic joint instability with larger sized capsulotomies, but also propose the complete capsular closure as an appropriate solution.

Mechanical Contribution of the Rib Cage in the Human Cadaveric Thoracic Spine.

An in vitro biomechanical human cadaveric study of T1-T12 thoracic specimens was performed with 4 conditions (with and without rib cage, instrumented and uninstrumented) in flexion-extension, lateral bending, and axial rotation. The objective was to understand the influence of the rib cage on motion and stiffness parameters of the human cadaveric thoracic spine. Hypotheses tested for overall motion in all modes of bending for both uninstrumented and instrumented specimens were (i) in-plane range of motion and neutral and elastic zones will be greater without the rib cage, (ii) neutral and elastic zone stiffness values will be different for specimens without the rib cage, and (iii) out-of-plane rotations will be different for specimens without the rib cage. The rib cage is presumed to provide significant stability to the thoracic spine, but no studies have been conducted to determine the influence of the rib cage in both uninstrumented and instrumented conditions in the full thoracic human cadaveric specimens. Seven human cadaveric spine specimens (T1-T12) with 4 conditions (with and without rib cage, instrumented and uninstrumented) were subjected to 5 N·m pure moments in flexion-extension, lateral bending, and axial rotation. Range of motion, neutral and elastic zones, neutral and elastic zone stiffness values, and out-of-plane rotations were calculated for the overall specimen. In-plane range of motion was significantly higher without a rib cage for most modes of bending. Out-of-plane motions were also influenced by the rib cage. Neutral zone stiffness was significantly higher with a rib cage present. Testing without a rib cage yields different motion and stiffness measures, directly impacting the translation of research results to clinical interpretation. Researchers should consider these differences when evaluating the mechanical impact of surgical procedures or instrumentation in cadaveric or computational models. 5.

Can balance training affect the ankle joint stiffness in subjects with unilateral chronic ankle instability?

Background: Lateral ankle sprain is one of the most frequent sports-related injuries, accounting for up to 60% of all athletic injuries. The development of repetitive ankle sprains and persistent residual symptoms such as repeated episodes of ankle giving way, pain, weakness, loss of function, and feeling of ankle instability after injury has been termed chronic ankle instability (CAI). The signs and symptoms of initial injury often resolve with time but mechanical joint laxity may last longer leading to residual symptoms. Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with CAI but the biomechanical and/or neurophysiological pathways underlying the clinical outcomes are still unknown. Balance training is routinely used in clinical practice for sprained ankles, however to our knowledge, only one study has examined the effects of balance training intervention on flexibility characteristics of the ankle joint in patients with CAI. Purpose: This study was conducted to determine if a 4week balance training intervention can alter the mechanical characteristics in ankles with CAI. Methods: Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n= 11, 35.1± 9.3 years) or intervention (n= 11, 33.5± 6.6 years) group. Subjects in the intervention group were trained on the affected limb with static and dynamic components using a Biodex balance stability system for 4-weeks. The ankle joint stiffness and neutral zone in inversion and eversion directions on the involved and uninvolved limbs was measured at baseline and post-intervention using a dynamometer. Results:Atbaseline, themeanvalues of the inversion stiffness (0.69± 0.37Nm/degree) in the involved ankle was significantly lower (p< 0.011, 95% CI [0.563, 0.544]) than that of uninvolved contralateral ankle (0.99± 0.41Nm/degree). With the available sample size, the eversion stiffness, inversion neutral zone, and eversion neutral zone were not found to be significantly different between the involved and uninvolved contralateral ankles. The 4-week balance training intervention failed to show any significant effect on the passive ankle stiffness and neutral zones in inversion and eversion. Conclusion(s): Decreased inversion stiffness in the involved chronic unstable ankle was found that of uninvolved contralateral ankle. The 4-week balance training program intervention was ineffective in altering the mechanical characteristics of ankles with CAI. Implications:Traditionally, taping and bracing have been used to improve stability and prevent recurrent ankle injury in patients with CAI. However, the beneficial effects of ankle taping have been attributed to enhanced proprioception and mechanical restriction, but there is no indication of restoring ligamentous stability. Further research with additional stiffness measures along with functional tests, larger sample size, and progressive balance training exercises is needed to identify if the mechanical characteristics of chronic unstable ankles can be altered.

Biomechanical effects of craniocervical instability on atlantoaxial lateral joint

Object To analyze the effects of craniocervical junction instability caused by ligament resection on the neutral zones(NEs) and range of motions(ROMs) in C1-2 motion segment, and the maximum pressure of atlantoaxial lateral joint. Methods 6 cases of fresh cadaver specimens were used. By using the method of repeated measurements, NZs and ROMs in C1~2 motion segment were measured for normal control group and the craniocervical instability group under 2.0Nm and 1.0Nm pure moment loading of flexion extension, lateral bending and axial rotation, respectively. Results The NZs in C1~2 motion under the loadings of flexion and extension, lateral bending and axial rotation for craniocervical junction instability group were 26.67°±4.70°、9.13°±1.32°and 63.11°±5.87°, respectively. The NZs in C1~2 motion under the loadings of flexion and extension, lateral bending and axial rotation for craniocervical junction instability group were 14.12°±2.40°, 4.15°±0.75°and 50.75°±5.84°, respectively. The NZs in C1~2 motion segment for craniocervical instability group in the loadings of flexion and extension, lateral bending and axial rotation were significantly greater than those for intact group (P<0.05). The ROMs in C1~2 motion under the loadings of flexion and extension, lateral bending and axial rotation for craniocervical junction instability group were 42.37°±3.96°、13.67°±1.10°and 78.50°±4.00°, respectively. The ROMs in C1~2 motion under the loadings of flexion and extension, lateral bending and axial rotation for craniocervical junction instability group were 27.43°±2.41°、6.97°±0.59°and 65.26°±4.08°, respectively. The ROMs for craniocervical junction instability group in the loadings of flexion and extension, lateral bending and axial rotation significantly were higher than those for the intact group (P<0.05). For flexion, lateral bending and left axial rotation, the maximum stress of the atlantoaxial lateral joints for craniocervical instability group was less than that for the intact group. In the loadings of extension and right axial rotation, the maximum stress of the atlantoaxial right lateral joints for craniocervical instability group was less than that for the intact group, too.Howerer the atlantoaxial right lateral joint was unchanged under the extension laoding , and the left joint is a litte higher than that of the intact group under right axial loading. Conclusion Simple ligament resection in craniocervical junction could cause atlantoaxial instability. The range of motion for the loadings of flexion and extension, lateral bending and axial rotation is higher than that of the intact group. Atlantoaxial instability might lead to loss of load-bearing function of atlantoaxial lateral joint, and ultimately result in atlantoaxial dislocation. Key words: Craniocervical junction; Atlantoaxial lateral joint; Atlantoaxial dislocation; Stress; Range of motion

A ROLE OF POPULATION HETEROGENEITY AND pH FACTOR IN NATURAL α-ACETOLACTATE SUPERSYNTHESIS IN A DIACETYL PRODUCER, Lactococcus lactis ssp. lactis bv. diacetylactis B2103/74

The effect of the population heterogeneity and medium pH on the found out by us supersynthesis of а-acetolactate (AL) by the L. lactis bv. diacetyllactis B2103/74 culture has been investigated. The nature of an enzyme system that is responsible for this effect due to lactate dehydrogenase essentially blocking by intercepting up to 80% NADH from it and was indicated as hemin-independent electron-transferring system (HIETS) is unknown. It was shown that the effect was disguised by the culture heterogeneity which was the most pronounced at neighboring to neutral pH values 6.1—6.5. It was established that at least three types of dissociants with different HIETS and, consequently, AL levels occurred in the population: active dissociant (AL accumulation up to 30 mM); inactive dissociant that lost HIETS activity (AL content of no more than 3 mM); and dissociant with moderate activity (AL content 15—17 mM). It was demonstrated that HIETS played a major part in the whole pyruvate metabolism at various pH and finally in the AL supersynthesis. For instance, at pH =7.0, the effect of supersynthesis failed to be observed due to the HIETS low activity, and the pyruvate metabolism proceeded by the homolactic pathway. However, at pH 5.3—6.5, the HIETS activity was so high that it permitted the system to take over a function of the major regulator of the redox NAD+/NADH balance leaving the minor part to LDH. The productivities of LDH and acetolactate-synthase pathways depended on the HIETS activity at various pH values, whereas that of the pyruvatedehydrogenase pathway was a straight function of external pH. The latter was rather high in the close to neutral pH area (6.0—6.5) and was significantly lower in the neutral (pH=6.0—6.5) and light-acidic (pH<6.0) zones.

The assessment of sensory detection thresholds on the perineum and breast compared with control body sites.

Few studies explored multiple sensory detection thresholds on the perineum and breast, but these normative data may provide standards for clinical conditions such as aging, genital and breast surgeries, pathological conditions affecting the genitals, and sexual function. The aim of this study was to provide normative data on sensory detection thresholds of three sensory modalities on the perineum and breast. Thirty healthy women aged between 18 and 35 years were assessed on the perineum (clitoris, labia minora, vaginal, and anal margin), breast (lateral, areola, nipple), and control body locations (neck, forearm, abdomen) for three sensory modalities (light touch, pressure, vibration). Average detection thresholds for each body location and sensory modality and statistical comparisons between the primary genital, secondary sexual, and neutral zones were the main outcome measures. Average detection thresholds for light touch suggest that the neck, forearm, and vaginal margin are most sensitive, and areola least sensitive. No statistical difference is found between the primary and secondary sexual zones, but the secondary sexual zone is significantly more sensitive than the neutral zone. Average detection thresholds for pressure suggest that the clitoris and nipple are most sensitive, and the lateral breast and abdomen least sensitive. No statistical difference is found between the primary and secondary sexual zone, but they are both significantly more sensitive than the neutral zone. Average detection thresholds for vibration suggest that the clitoris and nipple are most sensitive. The secondary sexual zone is significantly more sensitive than the primary and neutral zone, but the latter two show no difference. The current normative data from sensory detection threshold are discussed in terms of providing standard values for research and clinical conditions. Additional analysis from breast volume, body mass index, hormonal contraception, menstrual cycle, and sexual orientation do not seem to influence the results. Sexual abstinence and body piercing may have some impact.

What can a concept do? Rethinking education's queer assemblages

In a discussion of Deleuze's theorization of concepts, Todd May asks “what can a concept do with that which cannot be identified?” Or to put it another way, May writes – “A concept is a way of addressing the difference that lies beneath the identities we experience.” This is not to say that identities, concepts, and experiences are linked in particular ways. The possibility of extending what a concept can do is also brought under scrutiny by Ann Burlein, who draws on the work of Elizabeth Wilson to argue “Feminism needs to engage with scientific authority not simply at those sites where it [science] takes women as its objects, but also in the neutral zones, in those places where feminism appears to have no place or political purchase.” “Why not feminist critiques of the liver or the stomach, she asks?” Such styles of thought are the inspiration for this paper. We argue that queer concepts in education should not stop at places where education takes queer bodies as its objects, but that queer concepts have an important role to play in places where, at first glance, they appear to have no place or purchase.

Values Education through Literature in English Classes

Schools are not value-free or value neutral zones of social and educational engagement, but they are about building character as much as equipping students with specific skills, and values education is an explicit goal aimed at promoting care, respect and cooperation.Values education is a way of conceptualising education that places the search for meaning and purpose at the heart of the educational process. It recognises that the recognition, worth and integrity of all involved in the life and work of the school, are central to the creation of a values-based learning community that fosters positive relationships and quality in education. The research aims to explore the values pre-service English language teachers have. The results of the research may add an additional level to the understanding of students’ functioning in class and real life. One hundred and twenty pre-service English language teachers participate in this research. To accomplish the aim, the teacher trainees will be given a semi-structured interview based on Carl Rogers (1969) and Paulo Freire (1998) to test how they address the moral dilemmas in the literary texts they have studied in literature classes.

Smart Electrical Infrastructure for AC-Fed Railways With Neutral Zones

This paper presents a proposal to modify power supply systems currently used in ac-fed railways with neutral zones (NZs), in order to allow power-flow routing. The proposed system complements the existing infrastructure with additional power-electronic devices connected in parallel to both sides of the NZs, allowing control of power flow through adjacent electrical sections. The description and control of such a modified railway system is outlined in this paper. In addition, a mixed-integer programming optimization problem is formulated, which minimizes the investment and the operation costs, while ensuring the power supply to the train traffic. This optimization model is used to allow a systematic evaluation of the benefits of implementing such a railway smart grid system. Finally, a section of the high-speed line between Madrid and Barcelona is used as a case study, and the advantages of the proposed system are quantified in two different scenarios.

Experimental exploration of underexpanded supersonic jets

Two underexpanded free jets at fully expanded Mach numbers Mj = 1.15 and 1.50 are studied. Schlieren visualizations as well as measurements of static pressure, Pitot pressure and velocity are performed. All these experi- mental techniques are associated to obtain an accurate picture of the jet flow development. In particular, expansion, com- pression and neutral zones have been identified in each shock cell. Particle lag is considered by integrating the equation of motion for particles in a fluid flow and it is found that the laser Doppler velocimetry is suitable for investigating shock- containing jets. Even downstream of the normal shock arising in the Mj = 1.50 jet, the measured gradual velocity decrease is shown to be relevant.

Biomechanical analysis on different fixation techniques for treatment of mandibular body fractures

AIM: To biomechanically analyze two fixation techniques in polyurethane hemi-mandibular body fractures, using a universal testing machine. METHODS: The study employed 10 polyurethane hemi-mandible replicas, which simulated simple fractures of the mandibular body, divided into two groups: one group comprised 5 hemi-mandibles with two 2.0 mm system plates in the tension and compression zones, while the other group contained 5 hemi-mandibles with an Erich bar and a 2.0 mm system plate in the tension and neutral zones, respectively. Data were analyzed statistically by the Student's t-test (α=0.05) RESULTS: The test results indicated that the fixation using 2.0 mm system plates offered significantly more resistance to the loads and presented significantly larger displacement compared to the fixation using just one 2.0 mm system plate and the Erich bar. CONCLUSIONS: It may be concluded that the use of two plates in the 2.0 mm system had greater mechanical strength than a single 2.0 mm plate combined with an Erich bar. Clinically, it is known that both techniques can provide good results, but patients receiving the combination of Erich bar and one plate are required to be more cooperative during the postoperative period, especially with respect to the prescribed diet in order to avoid failures in this system.

Complexity of neutral zones, lumbar stability and subsystem adaptations: Probable alterations in lumbosacral transitional vertebrae (LSTV) subtypes

Physiological and anatomical ranges of movements at lumbar and lumbo-sacral motion segments are influenced by passive (bones and ligaments) and active (muscles) elements. The movements are visualized in terms of intrinsically unopposed (Neutral Zones) or opposed (Transitional Zones) movement zones. These two zones constitute the absolute ranges of motion for different regions of the spine. Though values of these ranges for flexion, extension, lateral bending and axial rotation at different spinal segments may demonstrate similarities across matched population, these parameters are most likely to show different values in lumbar spines affected with lumbo-sacral transitional vertebrae (LSTV). LSTV is a common variation of the lumbo-sacral junction and present well documented structural changes at the lower spine and L5/S1 vertebrae. This study attempts to (i) delineate and hypothesize relationships between changes in active and passive elements, (ii) understand the possibilities of restriction or augmentation in the values of these ‘zones’, and (iii) to predict overall LSTV induced physiological lumbar motion changes, in association with these variations.

Integral Control of Health Hazards in Hospital Environment

Hospitals present complex indoor environment with various users, health hazards and specific activities. This paper classifies health hazards specific to the hospital environment (HE), defines their interactions and possible impacts on human health and summarizes recommendations for biological and chemical hazards. A detailed literature review clearly shows that there is no developed system or method for integral control of health hazards in HE. There is no appropriate technology available that would allow development of optimal thermal comfort conditions for individual users in HE. For integral control of physical hazards, an innovative low exergy (LowEx) system was designed and tested. The system enables individual control of thermal comfort parameters to meet the needs of various users in the same room. It enables the design of optional conditions for healthcare and treatment considering the different requirements of individual patients and thermally neutral zones for other users. The system application is presented in a model room for burns patient. The measured energy use was lower by 11–27% for space heating and by 32–73% for cooling, when using LowEx system as compared to the conventional system. Owning to its flexibility, the system can also be used for other potential users.

Influence of the long-term operation of 12Kh1M1F steel from different zones of a bend of steam pipeline of a thermal power plant on its mechanical characteristics

We estimate the characteristics of strength, ductility, and static crack resistance of 12Kh1MF steel taken from the stretched, compressed, and neutral zones of a vertical bend and a straight part of the main steam pipeline of a thermal power plant after ~ 1.3 ⋅105 h of operation. The anisotropy of the mechanical char acteristics in the diametric and axial sections of the pipe and their gradients across the thickness of the pipe wall in fracture are discovered.

Modelling the structure of the hot components in symbiotic binaries during outbursts

AbstractDuring outbursts in symbiotic binaries a neutral medium in the form of a flared disk develops around their hot stars. The appearance of the disks is most probably connected with the enhanced wind from the hot star. The wind is compressed towards the equatorial plane of the hot star due to its rotation. To test this idea we calculated the ionization boundaries in the enhanced wind and thus confirmed the possibility of the formation of the neutral disk-like zones around the hot stars in symbiotic binaries during outbursts.

Formation of Neutral Disk-Like Zone Around the Active Hot Stars in Symbiotic Binaries

Abstract In this contribution we present the ionization structure in the enhanced wind from the hot star in symbiotic binaries during active phases. Rotation of the hot star leads to the compression of the outflowing material towards its equatorial plane. As a result, a neutral disk-like zone around the active hot star near the orbital plane is created. We modeled the compression of the wind and calculated the neutral disk-like zone in the enhanced wind from the hot star using the equation of the photoionization equilibrium. the presence of such neutral disk-like zones was also suggested on the basis of the modeling the spectral energy distribution of symbiotic binaries. We confront the calculated ionization structures in the enhanced wind from the hot star with the observations. the calculated column density of the neutral hydrogen atoms in the neutral disk-like zone and the emission measure of the ionized part of the wind from the hot star are in a good agreement with the quantities derived from observations during active phases. the presence of such neutral disk-like zones is transient, being connected with the active phases of symbiotic binaries. During quiescent phases, such neutral disk-like zones cannot be created because of insufficient mass-loss rate from the hot star.