Fabrication and characterization of 3-dimensional electrospun poly(vinyl alcohol)/keratin/chitosan nanofibrous scaffold.

Layer-by-layer three-dimensional nanofibrous scaffolds (3DENS) were produced using the electrospinning technique. Interest in using biopolymers and application of electrospinning fabrication techniques to construct nanofibers for biomedical application has led to the development of scaffolds composed of PVA, keratin, and chitosan. To date, PVA/keratin blended nanofibers and PVA/chitosan blended nanofibers have been fabricated and studied for biomedical applications. Electrospun scaffolds comprised of keratin and chitosan have not yet been reported in published literature, thus a novel nanofibrous PVA/keratin/chitosan scaffold was fabricated by electrospinning. The resulting 3DENS were characterized using fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential scanning colorimetry (DSC), and thermogravimetric analysis (TGA). Physiochemical properties of the polymer solutions such as viscosity (rheology) and conductivity were also investigated. The 3DENS possess a relatively uniform fibrous structure, suitable porosity, swelling properties, and degradation which are affected by the mass ratio of keratin, and chitosan to PVA. These results demonstrate that PVA/keratin/chitosan 3DENS have the potential for biomedical applications.

Prediction of applied pressure on model lower limb exerted by an air pneumatic device.

Air pneumatic compression is a concept used for management of venous disease, including oedema. A typical air pneumatic compression device (PCD) consists of an inflatable sleeve composed of either single or multiple pressure chambers that encircle a limb. The aim of this research was to develop a mathematical model to predict the pressure applied by an air pneumatic device to an irregular cross-sectional lower limb manikin. The radius of curvature at any cross-section of the lower limb (i.e. calf (gastrocnemius), tibial crest (anterior edge of the tibia bone)) is irregular, and differs amongst individuals and populations. The effectiveness of air pneumatic devices is difficult to predict with these irregular cross sections. A theoretical model was developed to calculate pressure applied by compression sleeves on a lower leg manikin and results compared against experimental pressure exerted on the manikin by a silicone-based PCD. This prediction was made at each of three positions. The theoretical model developed based on elliptical shaped forms predicted the pressure more accurately for the ankle to above ankle position, whereas the model based on circular shaped forms predicted the pressure more accurately for below the calf to below the knee position. Refinements to the theoretical model to predict the pressure applied by PCD are recommended.

Textile-based compression therapy in managing chronic oedema: Complex interactions.

BACKGROUND: Compression is a common therapy for management of chronic disease, including oedema of the lower limb. Modern compression interventions exert pressure on the lower limb through use of one or more materials which exert pressure against the limb over time. Where these materials are textiles, they range from elastic to inelastic, and are produced using knitting, weaving, or other textile technologies which can be manipulated to control performance properties. Thus, understanding of both the materials/textiles and the human body is needed if the most appropriate compression device and treatment strategy is to be used. Neither is independent of the other. This review aims to enhance understanding of critical textile performance properties and how selection of textiles may affect treatment efficacy when managing chronic oedema of the lower limb. METHOD: Relevant papers for review were identified via PubMed Central® library, and Google Scholar using keywords associated with textile-based treatments of the oedematous lower limb and wider interdisciplinary factors. RESULTS: Assessment of the disorder, the severity of oedema, and location of fluid accumulation are required to inform treatment of chronic oedema. While the need to understand the patient is well established (e.g. age, sex, body mass index, skin thickness and colour, patient compliance with treatment), information about preferred compression systems and material structures, and inherent properties of these, is generally lacking. CONCLUSION: Greater detail about materials used (e.g. fabric structure, number and order of layers, fibre content) and patient diagnosis (e.g. underlying cause, severity, location of oedema; patient age and sex; evidence of compliance with treatment; pressure exerted; lower leg shape, size, and properties of the tissue) is needed to facilitate advances in efficacy of compression treatment. Reduced limb swelling with a textile-based treatment occurs simultaneously with changes to the textile itself. Textiles cannot be considered inert.

Understanding Stress-Strain Behavioral Change in Fabrics for Compression Bandaging.

Bandages are common in many health-related treatments, including management of edema of the lower limb where they may remain in place for several days. The behavior of 2 bandage fabrics was investigated after exposure for up to 5 days to a multiaxial extension laboratory setup on a tensile tester in compression mode. The fabrics were extended 20% and remained under that machine setting. Stress-relaxation over time was determined by analyzing the rate of change over 24 hours and over 5 days. Most change, a rapid drop in force, occurred during the first 15 minutes; thereafter, for the next 12-hour period, a slower rate of decrease was observed. Both fabrics continued to relax gradually during the next 12 hours and continued to do so for up to 5 days. Little further change was evident during the last 12 hours or so. This phenomenon suggests that rewrapping may be appropriate (albeit not practical) after 12 hours of compression therapy to optimize the compression given to the lower leg. Relaxation behavior of these 2 fabrics can be explained using the generalized Maxwell-Wiechert model.

Layering garments during rest and exercise in the cold (8°C): wearer responses and comparability with selected fabric properties.

How garments contribute to performance of the clothing system during wear is of interest, as is understanding the value of using fabric properties to inform end-use characteristics. To investigate the influences of layering upper-body garments, four fabrics were used to construct two first-layer garments (wool and polyester) and two outer-layer garments (wool and membrane laminate). Over six sessions, 10 moderately trained males wore each first-layer garment as a single layer and in combination with each outer-layer garment while resting, running and walking in cold environmental conditions (8 ± 1°C, 81 ± 4% RH). Here, the type of garment arrangement worn (fabric type or number of layers) had little influence on heart rate, core body temperature and change in body mass. Weighted mean covered skin temperature was warmer and weighted mean next-to-skin vapour pressure was typically higher (following the onset of exercise) with two layers versus one. Differences among fabrics for individual properties were typically overstated compared to differences among corresponding garments for physiological and psychophysical variables under the conditions of this study. These findings inform the interpretation of particular fabric properties and highlight issues to be acknowledged during development/refinement of fabric test methods. PRACTITIONER SUMMARY: We examined the way in which selected fibre, fabric and garment (layering) characteristics contribute to performance of the clothing system during wear under cold conditions. Selected properties of the constituent fabrics were found to provide limited insight into how garments perform during wear under the conditions of this study.

Pressure and coverage effects of sporting compression garments on cardiovascular function, thermoregulatory function, and exercise performance.

Sporting compression garments (CG) are used widely during exercise despite little evidence of benefits. The purpose of this study was to investigate coverage and pressure effects of full-body CG on cardiovascular and thermoregulatory function at rest and during prolonged exercise, and on exercise performance. Twelve recreationally trained male cyclists [mean (SD) age, 26 (7) years; VO(2 max), 53 (8) mL kg(-1) min(-1)] completed three sessions (counterbalanced order), wearing either correctly-sized CG (CSG; 11-15 mmHg), over-sized CG (OSG; 8-13 mmHg), or gym shorts (CONT). Test sessions were conducted in temperate conditions [24 (1)°C, 60 (4)% relative humidity; ~2 m s(-1) air velocity during exercise], consisting of resting on a chair then on a cycle ergometer, before 60-min fixed-load cycling at ~65% VO(2 max) and a 6-km time trial. Wearing CG (CSG or OSG) did not mitigate cardiovascular strain during mild orthostatic stress at rest (p = 0.20-0.93 for garment effects). During exercise, cardiac output was ~5% higher in the CG conditions (p < 0.05), which appears to be accounted for via non-significant higher end-exercise heart rate (~4-7%, p = 0.30; p = 0.06 for greater heart rate drift in CSG); other cardiovascular variables, including stroke volume, were similar among conditions (p = 0.23-0.91). Covered-skin temperature was higher in CG conditions (p < 0.001) but core (oesophageal) temperature was not (p = 0.79). Time-trial performance (mean power, time taken) was similar with or without CG (p = 0.24-0.44). In conclusion, any demonstrable physiological or psychophysical effects of full-body CG were mild and seemingly reflective more of surface coverage than pressure. No benefit was evident for exercise performance.

Compression garments and exercise: garment considerations, physiology and performance.

Compression garments (CGs) provide a means of applying mechanical pressure at the body surface, thereby compressing and perhaps stabilizing/supporting underlying tissue. The body segments compressed and applied pressures ostensibly reflect the purpose of the garment, which is to mitigate exercise-induced discomfort or aid aspects of current or subsequent exercise performance. Potential benefits may be mediated via physical, physiological or psychological effects, although underlying mechanisms are typically not well elucidated. Despite widespread acceptance of CGs by competitive and recreational athletes, convincing scientific evidence supporting ergogenic effects remains somewhat elusive. The literature is fragmented due to great heterogeneity among studies, with variability including the type, duration and intensity of exercise, the measures used as indicators of exercise or recovery performance/physiological function, training status of participants, when the garments were worn and for what duration, the type of garment/body area covered and the applied pressures. Little is known about the adequacy of current sizing systems, pressure variability within and among individuals, maintenance of applied pressures during one wear session or over the life of the garment and, perhaps most importantly, whether any of these actually influence potential compression-associated benefits. During exercise, relatively few ergogenic effects have been demonstrated when wearing CGs. While CGs appear to aid aspects of jump performance in some situations, only limited data are available to indicate positive effects on performance for other forms of exercise. There is some indication for physical and physiological effects, including attenuation of muscle oscillation, improved joint awareness, perfusion augmentation and altered oxygen usage at sub-maximal intensities, but such findings are relatively isolated. Sub-maximal (at matched work loads) and maximal heart rate appears unaffected by CGs. Positive influences on perceptual responses during exercise are limited. During recovery, CGs have had mixed effects on recovery kinetics or subsequent performance. Various power and torque measurements have, on occasions, benefitted from the use of CGs in recovery, but subsequent sprint and agility performance appears no better. Results are inconsistent for post-exercise swelling of limb segments and for clearance of myocellular proteins and metabolites, while effects on plasma concentrations are difficult to interpret. However, there is some evidence for local blood flow augmentation with compression. Ratings of post-exercise muscle soreness are commonly more favourable when CGs are worn, although this is not always so. In general, the effects of CGs on indicators of recovery performance remain inconclusive. More work is needed to form a consensus or mechanistically-insightful interpretation of any demonstrated effects of CGs during exercise, recovery or - perhaps most importantly - fitness development. Limited practical recommendations for athletes can be drawn from the literature at present, although this review may help focus future research towards a position where such recommendations can be made.

Protection provided by clothing and textiles against potential hazards in the operating theatre.

The typical hospital and operating theatre present multiple potential hazards to both workers and patients, and protection against some of these is provided through use of various forms of clothing and textiles. While many standards exist for determining the performance of fabrics, most tests are conducted under laboratory conditions and against a single hazard. This paper provides an overview of selected developments in the principal properties of fabrics and garments for use in these workplaces, identifies the key standards, and suggests topics for further investigation.