[The evaluation of bacteria penetration by medical textiles for multiple use and disposable multilayer surgical drapes, according to the PN-EN ISO 22610 standard]

INTRODUCTION

Cotton as well as synthetic textile medical products are widely used as barrier materials and individual protection against displacement of biological infectious factors. The required level of protection of these products for multiple use and disposable multilayer laminates against the penetration of microbes depends on the risk connected with type of surgical procedure defined in normative documents. METHODS. Cotton and syntetic medical textiles for multiple use, 30-times subjected to processes simulating conditions of the use as well as disposable multilayer surgical drapes were tested. Resistance to microbial wet penetration was conducted according to the PN-EN ISO 22610: 2007 standard.

RESULTS

The barrier of cotton fabrics was reduced after first washing and then systematically grew after each often cycles to the value close to the value at the beginning. From the twentieth cycle of simulated conditions of the use, barrier index was reduced. The barrier of the synthetic textile stayed on the average level, while multilayer disposable products ensured the full impermeability for the bacteria.

CONCLUSIONS

Natural cotton textiles for multiple use could be apply on operative blocks in limited range because of the changes of the cotton structure caused by repeated laundering process and sterilization. Synthetic materials also have limited application, although are more resistant to cleaning and sterilization processes. Disposable synthetic laminates with many layers use guarantee impermeability for bacteria and may be applied in operative blocks without restrictions.

Phase change materials and the perception of wetness

Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead of cold. In order to investigate if this phenomenon occurs when manipulating textiles, nine subjects were asked to touch or manipulate PCM-treated and untreated fabrics. In 75% of the cases, the subjects indicated that the treated material felt wetter than the untreated material independent of the way the textiles were manipulated. We conclude that incorporating PCMs in textiles may lead to a feeling of wetness which might be uncomfortable. Therefore, we recommend investigating a change in cooling properties to minimise this feeling.

PRACTITIONER SUMMARY

This article describes a psychophysical experiment into the sensation of wetness of textiles treated with phase change materials. It was found that in 75% of the cases, subjects found the treated fabric to feel wetter than the untreated. This may affect the comfort of wearing clothes made of these textiles.

Evaluation of thermal and moisture management properties on knitted fabrics and comparison with a physiological model in warm conditions

This study reports on an experimental investigation of physical properties on the textile thermal comfort. Textile properties, such as thickness, relative porosity, air permeability, moisture regain, thermal conductivity, drying time and water-vapour transmission rate have been considered and correlated to the thermal and vapour resistance, permeability index, thermal effusivity and moisture management capability in order to determine the overall comfort performance of underwear fabrics. The results suggested that the fibre type, together with moisture regain and knitted structure characteristics appeared to affect some comfort-related properties of the fabrics. Additionally, thermal sensations, temperature and skin wetness predicted by Caseto® software for three distinct activity levels were investigated. Results show that the data obtained from this model in transient state are correlated to the thermal conductivity for the temperature and to Ret, moisture regain and drying time for the skin wetness. This provides potential information to determine the end uses of these fabrics according to the selected activity level.

[Legal requirements concerning textile medical products]

Presently, more and more often the medical public is concerned with questions regarding use of textile products intended for multiple application at operating theatres. Such questions have been evoked especially by spreading information on restrictions regarding purchase and us of health care products or medical means made from cotton of intended for multiple application. Based on this information preference is given to significantly more expensive products intended for single-use only. This decision is being reasoned by conditions given by European standard EN 13795 reportedly prohibiting the application of cotton within health care. Since this piece of information is not precise, we would like to sum-up legislative situation within this area.

[Hygienic assessment of children's clothes made using new-generation textile auxiliaries]

The paper presents the results of sanitary-and-chemical studies of samples of tissues treated with new-generation textile auxiliaries (TAs). The application of new-generation TAs containing the lower levels of formaldehyde (FA) is shown not to eliminate the problem of their safe use in making children's clothes. The safe values for exposure to FA have been estimated in relation to the real load of a garment. The toxic action of cutaneous versus intragastric FA has been evaluated in immature rats. The clothes FA level of 20 microg/g has been found to produce no toxic effect on a living organism.

New objective measurement to characterize the porosity of textile implants

The inflammatory and fibrotic intensity of a foreign body reaction largely depends on the porosity of the implanted material. Furthermore, the size of the pore and its geometry define the capability to allow tissue ingrowth. We present an image analysis system, which allows objectifying in two dimensions the pores' structure and geometry of textile fabrics, that are used to reinforce the abdominal wall or pelvic floor. The porosity of the textile is measured at four samples with differences in structure. The porosity decreases markedly if foreign body response is considered, leading to the definition of an "effective porosity". Because of the high stiffness of the polymer fibers the elasticity of textile implants usually result from a deformation of the pores, leading to a marked reduction of the effective porosity if a mechanical stress is applied. Further in vivo studies have to investigate, whether the preservation of a high effective porosity under stress may help to improve biocompatibility of textile implants.

High temperature ablation of kaolinite layered silicate/phenolic resin/asbestos cloth nanocomposite

The successful return of re-entry space vehicle, which is subjected to severe aerodynamic heating, is largely accompanied by some provisions to reduce the heat transfer to the structure. Heat shield is the best protection means which undergoes physical, chemical, and mostly endothermal transformations. The objective of this work is to investigate the ablating, charring, and thermal degradation behaviour of heat shield resol-type phenolic resin/kaolinite/asbestos cloth nanocomposite by oxyacetylene flame test with an external heat flux of 8 x 10(9)W/m(2) and 3000 K hot gas temperature and thermal analyzer techniques. Kinetic parameters of thermal degradation and temperature distribution at the back surface of the nanocomposite heat shield were determined and compared with that of composite counterpart.

Analysis of the products from enzymatic scouring of cotton

This article discusses the analysis of the hydrolysis products from one-step scouring of cotton using pectinase and two-step scouring of cotton using lipase then cellulase, protease then cellulase, or lipase/protease then cellulase, to improve water absorbency of cotton. UV spectrophotometric analysis indicated that the pectinase scouring process produced approximately 18-fold higher amounts of reducing sugars and galacturonic acid than any of the two-step scouring processes. The production rate of reducing sugars and galacturonic acid from most of the scouring processes showed a decrease with an increase in time. HPLC analysis revealed that the lipase/protease/cellulase scouring processes produced approximately 5-fold higher amounts of 17 amino acids than the pectinase scouring process. GC analysis for 18 fatty acids (C(8)-C(24)) revealed that three major fatty acids, palmitic acid, stearic acid, and behenic acid, were found on both the scoured and the unscoured fabrics. Scoured fabrics were tested for content of proteins, extractable components, waxes, and anionic components including pectins, and some differences among the fabric scoured with different enzyme combinations were found.

Wax removal for accelerated cotton scouring with alkaline pectinase

A rational approach has been applied to design a new environmentally acceptable and industrially viable enzymatic scouring process. Owing to the substrate specificity, the selection of enzymes depends on the structure and composition of the substrate, i.e. cotton fibre. The structure and composition of the outer layers of cotton fibre has been established on the basis of thorough literature study, which identifies wax and pectin removal to be the key steps for successful scouring process. Three main issues are discussed here, i.e. benchmarking of the existing alkaline scouring process, an evaluation of several selected acidic and alkaline pectinases for scouring, and the effect of wax removal treatment on pectinase performance. It has been found that the pectinolytic capability of alkaline pectinases on cotton pectin is nearly 75% higher than that of acidic pectinases. It is concluded that an efficient wax removal prior to pectinase treatment indeed results in improved performance in terms of hydrophilicity and pectin removal. To evaluate the hydrophilicity, the structural contact angle (theta) was measured using an auto-porosimeter.

Easily available enzymes as natural retting agents

Easily available commercial enzymes currently have great potential in bast fibre processing and can be modified for different end uses. There are several new technologies using enzymes that are able to modify fibre parameters, achieve requested properties, improve processing results and are more beneficial to the ecology in the area of bast fibre processing and fabrics finishing. Enzymatic methods for retting of flax, "cottonisation" of bast fibres, hemp separation, and processing of flax rovings before wet spinning, etc., fall into this group of new technologies. Such enzymatic biotechnologies can provide benefits in textile, composite, reinforced plastic and other technical applications. Laboratory, pilot and industrial scale results and experiences have demonstrated the ability of selected enzymes to decompose interfibre-bonding layers based on pectin, lignin and hemicelluloses. Texazym SER spray is able to increase flax long fibre yields by more than 40%. Other enzymes in combination with mild mechanical treatment can replace aggressive and energy-intensive processing like Laroche "cottonisation". Texazym SCW and DLG pretreatments of flax rovings are presented.

A simple and exploratory way to determine the mean-variance relationship in generalized linear models

This paper introduces an exploratory way to determine how variance relates to the mean in generalized linear models. This novel method employs the robust likelihood technique introduced by Royall and Tsou.A urinary data set collected by Ginsberg et al. and the fabric data set analysed by Lee and Nelder are considered to demonstrate the applicability and simplicity of the proposed technique. Application of the proposed method could easily reveal a mean-variance relationship that would generally be left unnoticed, or that would require more complex modelling to detect.

Protection from visible light by commonly used textiles is not predicted by ultraviolet protection

Interest is increasing in the prevention of acute and chronic actinic damage provided by clothing. This interest has focused mainly on protection against ultraviolet irradiation, but it has now also turned to protection against visible light. This change is mainly due to the action spectrum in the visible light range of some photodermatoses and the increasing interest in photodynamic therapy. The ultraviolet protection provided by commercially available textiles can be graded by determining an ultraviolet protection factor. Several methods have already been used to determine the ultraviolet protection factor. The fact that protection from visible light by textiles cannot be predicted by their ultraviolet protection makes the situation more complicated. This study attempts to determine whether or not the ultraviolet protection factor value of a particular textile is a good parameter for gauging its protection in the visible light range and concludes that a protection factor of textile materials against visible light needs to be developed. This development should go beyond the protection factor definition used in this article, which has some limitations, and should take into account the exact action spectrum for which the protection is needed.

Statistical model of pesticide penetration through woven work clothing fabrics

Statistical models estimating the level of protection and thermal comfort performance of woven fabrics were developed using simple fabric and liquid parameters. Eighteen woven fabrics were evaluated against three pesticide mixtures of atrazine and pendimethalin at different concentrations. Using three mixtures that represent a range of both surface tension and viscosity, percentages of pesticide penetration are measured, along with fabric thickness, fabric cover factor, yarn twist factor, yarn packing factor, solid volume fraction, wicking height, and air permeability. Statistical analyses are performed to examine the relationship between liquid/fabric parameters and pesticide penetration. Statistical analyses show that fabric cover factor, yarn twist factor, viscosity of pesticide mixture, critical surface tension of solid, and wicking height are significant parameters affecting pesticide penetration. For this purpose, cover factor and twist factor are better parameters in describing the geometry of woven fabrics than solid volume fraction. Modeling of comfort performance of woven fabric based on simple textile parameters shows that the combination of fabric thickness, cover factor, yarn twist factor and yarn packing factor can be used to estimate air permeability of woven fabric. These findings could be used for developing selection charts or tools as guidelines for the selection of personal protective equipment for use in hot, humid environments.

Pressure garments for use in the treatment of hypertrophic scars -- an evaluation of current construction techniques in NHS hospitals

The purpose of this investigation was to establish the variety of pressure garment construction methods and materials used in UK hospitals. This paper reports an investigation conducted in two parts. First, a survey of pressure garment practitioners was conducted and second, 15 of the fabrics currently used in UK hospitals were tested. The results showed that the pressures exerted by pressure garments constructed in UK hospitals were likely to range from ineffectively low to dangerously high.

[New methodological approaches to the hygienic standards of clothes for children and adults]

The hygienic assessment is presently a research issue related mainly with commissioning new materials into production; the above issue is equally related with materials' diversity, with expanding the choice of commodities and with the multi-functionality of the latter as well as with modern technologies and with the forthcoming admittance of our country to the WTO, which necessitates a harmonization of regulating requirements in various countries. The old approaches towards regulations of cloths are outdated and are no longer in line with the requirements of today. The chemical stability of contemporary synthetic fibers and the narrowing-of-gap between their physical-and-hygienic indices and those of natural fibers ensures unified approaches towards the hygienic evaluation of both. A real load that is conceptually found as a product of the impact intensity on the impact duration time is a hygienically valuable criterion ensuring a universal approach towards regulating the cloths hygienic safety. A hygienic classification provides, in case of each item, for defining the index of its hygienic safety (HIS), which is a basis for designing the differential requirements towards cloths of various functional purposes and for various age groups. The area of contact with the skin during wear and the age of consumer are the key components of system (The Hygienic Classification of Cloths". The article is supplemented by 1 drawing, 2 tables and a list of literature (8 entries; article's volume is 5 pages).

Improving UV protection by clothing--recent developments

The assessment of UV transmittance of clothing and the determination of the UV protection factor (UPF) are now well established and the influencing factors such as type of fiber, color, and fabric construction are known. Quick and reliable instruments to measure UV transmittance are crucial. Besides expensive scientific laboratory instruments, a low-cost UV meter is now available for this purpose. The questions arise as to what can be done about a given garment and whether there are ways to improve textiles by the consumer. The many opportunities to improve UV protection of clothing along the textile chain of manufacturing are discussed. The latest possibility for improving the UV-protective properties of clothing is now available at the fabric care stage in every household. A UV absorber can be brought into contact with a fabric during the wash or rinse cycle of a laundry operation. The high UV transmittance of 30% of a thin, bleached cotton swatch in the dry state (UPF 3), can be reduced tenfold to about 3% (UPF >30) in ten washes cycles. This is more than the effect achieved by dyestuffs. The detergent should contain about 0.1-0.3% of the special UV absorber. The same effect can be achieved as early as after one wash cycle with a higher concentration provided by a special laundry additive. Yet another form of application is via rinse cycle fabric conditioner. To make these new types of improvement of fabrics visible the Skin Cancer Foundation now provides the possibility for laundry products to qualify for the "Seal of Recommendation".