Chi-Wai Kan

Wrinkle-resistant finishing of cotton fabric with BTCA - the effect of co-catalyst:

Fabrics treated with dimethyloldihydroxylethyleneurea (DMDHEU) are susceptible to formaldehyde release. High concentrations of formaldehyde have been reported to cause cancer in animal studies. Due to the toxicity of DMDHEU, the polycarboxylic acid class of non-formaldehyde crosslinking agents used for wrinkle-resistant treatment has been introduced. Among various researches, 1,2,3,4-butanetetracarboxylic acid (BTCA) is a desirable reactant when catalysed with sodium hypophosphite (SHP). The characteristics of TiO 2 or nano-TiO2, acting as a co-catalyst in a BTCA wrinkle-resistant finishing system are examined in this study. Surface morphology and molecular structure of cotton specimens together with the wrinkle-resistant, UV protection, yellowing, tensile and tearing properties of the treated specimens are also evaluated.

Phyllanthus urinaria extract attenuates acetaminophen induced hepatotoxicity: involvement of cytochrome P450 CYP2E1.

Acetaminophen is a commonly used drug for the treatment of patients with common cold and influenza. However, an overdose of acetaminophen may be fatal. In this study we investigated whether mice, administered intraperitoneally with a lethal dose of acetaminophen, when followed by oral administration of Phyllanthus urinaria extract, may be prevented from death. Histopathological analysis of mouse liver sections showed that Phyllanthus urinaria extract may protect the hepatocytes from acetaminophen-induced necrosis. Therapeutic dose of Phyllanthus urinaria extract did not show any toxicological phenomenon on mice. Immunohistochemical staining with the cytochrome P450 CYP2E1 antibody revealed that Phyllanthus urinaria extract reduced the cytochrome P450 CYP2E1 protein level in mice pre-treated with a lethal dose of acetaminophen. Phyllanthus urinaria extract also inhibited the cytochrome P450 CYP2E1 enzymatic activity in vitro. Heavy metals, including arsenic, cadmium, mercury and lead, as well as herbicide residues were not found above their detection limits. High performance liquid chromatography identified corilagin and gallic acid as the major components of the Phyllanthus urinaria extract. We conclude that Phyllanthus urinaria extract is effective in attenuating the acetaminophen induced hepatotoxicity, and inhibition of cytochrome P450 CYP2E1 enzyme may be an important factor for its therapeutic mechanism.

Antitumor activity of diethynylfluorene derivatives of gold(I)

A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as a function of their structure-activity relationships. End-capping the fluoren-9-one unit with gold(I) moieties could significantly strengthen the cytotoxic activity in vitro on three human cancer cell lines with induction of reactive oxygen species generation on Hep3B hepatocellular carcinoma cells and exhibit attractive antitumor activity from in vivo nude mice Hep3B xenograft model with limited adverse effects on vital organs including liver and kidney.

Corilagin is a potent inhibitor of NF-kappaB activity and downregulates TNF-alpha induced expression of IL-8 gene in cystic fibrosis IB3-1 cells

Corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), a gallotannin identified in several plants, including Phyllanthus urinaria, has been shown to exhibit versatile medicinal activities. As far as possible anti-inflammatory effects of corilagin, only few reports are available, and the potential use of corilagin as possible therapeutic molecule for cystic fibrosis has not been evaluated. In the present paper we report experiments aimed at determining the activity of corilagin on nuclear factor kappaB (NF-kappaB) binding to DNA target and on the expression of the major pro-inflammatory gene involved in cystic fibrosis, interleukin-8 (IL-8). Both IL-8 mRNA content and IL-8 protein secretion were analyzed in cystic fibrosis bronchial IB3-1 cells stimulated by tumor necrosis factor-alpha (TNF-alpha), one of the most potent pro-inflammatory agents. The data obtained demonstrate that corilagin binds to NF-kappaB, inhibits NF-kappaB/DNA interactions and affects IL-8 gene expression in TNF-alpha treated IB3-1 cells. In addition, corilagin inhibits TNF-alpha induced secretion of MCP-1 and RANTES, exhibiting low or no effect on the release of G-CSF, IL-6 and VEGF. Therefore, corilagin might be of interest for experimental anti-inflammatory therapy of cystic fibrosis.

Developments in functional finishing of cotton fibres – wrinkle-resistant, flame-retardant and antimicrobial treatments

Natural fibres, especially cotton, are still the most important kinds of fibres because of their numerous advantages such as high tensile strength, good abrasion resistance, high moisture absorption, quick drying and absence of static problems. However, cotton has poor elasticity and resilience, i.e. poor wrinkle recovery property. It is weakened easily by acids and resin chemicals used in finishing processes. In addition, fabrics made from untreated cotton fibres burn easily with a high flame velocity and are prone to being attacked by mildew and bacteria. Reducing wrinkling, flammability and microbial attacks of cotton fibre have been the major challenge facing the textile industry. The aim of this paper is to provide an overview of the current status of developments in functional finishing of cotton fabrics. Functional finishing agents, especially cross-linking agents, are embedded in cotton fabrics with the aid of acid catalysts, followed by drying and curing at high temperatures. The treated cotton fabrics often suffer from decrease in tensile strength, tear strength, abrasion resistance and sewability with a stiff, harsh and uncomfortable feel. Moreover, chemicals present in finishing agents react in the curing process to form some residues, which may even release free formaldehyde, which is of carcinogenic nature. The amount of formaldehyde remaining in the finished product depends largely on the amount and kind of finishing agents and catalysts used, as well as the curing conditions. Over the last decade, there have been many changes in the textile industry. The importance of environmental issues, which influence the direction of chemical finishing and reshaping the types of speciality chemicals used in textile wet processing, is a dominant theme in the market. Apart from the trend towards the use of environment-friendly chemical finishes, chemicals are being specially formulated for ease of application and high quality finishing. In this paper, the latest developments in textile functional finishing of cotton fabrics are critically reviewed and precisely described. The use of plasma surface treatment is one of the easiest and the most efficient ways to improve post-finishing of cotton fabrics. In general, the active species produced in plasma carry high energy to promote surface functionalisation reactions causing a sputtering or etching effect on cotton fabrics. The altered surface characteristics can still retain inherent advantages of cotton substrates and enhance material properties by incorporating with a large variety of chemically active functional groups. Furthermore, it may be necessary to add a suitable co-reactant to enhance the performance of chemical finishing and minimise the side effects. Recently, some finishing formulations involving catalytic effects induced by co-reactants have been developed. The aim of this paper is to critically and comprehensively examine the existing developments in textiles functional finishing, with special focus on wrinkle-resistant, flame-retardant and anti-microbial finishing of cotton fabrics. In addition, further developments of these finishing processes are discussed.

Chitosan microcapsules loaded with either miconazole nitrate or clotrimazole, prepared via emulsion technique.

In this paper, a simple and versatile coacervation technique has been developed by using an ultrasound-assisted oil/water emulsion method for the preparation of antifungal agent-loaded microcapsules. Two types of chitosan microcapsules are successfully prepared. The mean particle size of the chitosan/miconazole nitrate microcapsules is 2.6 μm and that of the chitosan/clotrimazole microcapsules is 4.1 μm. The encapsulation efficiency of the chitosan/miconazole nitrate microcapsules (77.58-96.81%) is relatively higher than that of the chitosan/clotrimazole microcapsules (56.66-93.82%). The in vitro drug release performance of the microcapsules shows that the chitosan/miconazole nitrate microcapsules release about 49.5% of the drug while chitosan/clotrimazole microcapsules release more than 66.1% of the drug after 12h under a pressure of 5 kg at pH 5.5, which is similar to the pH of human skin. The prepared drug-loaded microcapsules could be applied onto bandages or socks, and will continuously release antifungal drugs in a controlled manner under pressure.

Evaluation of water absorption and transport property of fabrics

The liquid absorption and transport properties of fabrics are critical not only to the success of wet processes such as dyeing, printing and finishing, but also to the performance of products such as sports clothes, performance clothing, disposable hygiene materials and medical products. During wear, moisture in clothing has been found to be the most significant factor contributing to discomfort. The presence of sweat will increase friction between fabric and skin, trigger a clingy sensation and eventually increase the level of fatigue felt by the wearer. This problem will be even more severe for clothing worn under extreme environmental conditions or at high activity levels. Fabrics with excellent water absorption and transport properties have the potential to minimise the wetness sensation on skin, facilitate the evaporation of sweat and aid comfort. Hence, as a product developer or clothing manufacturer, it is essential to choose the appropriate measurement method to characterise the water absorption and transport properties of fabric. This paper reviews different subjective (by people–subjects) and objective (by instruments–objects) evaluation methods for assessing wetness comfort, and determining water absorption and transport properties of fabrics. Since perception of wetness is a complex process with a number of stimuli from clothing and external environments communicated by human sensory receptors, subjective assessment with its better representation of the real wear situation is preferred. The review starts by introducing human physiology, describing hepatic perception of wetness, followed by methods for use in experiments on assessor control, setting of environmental conditions, types of touch, the usual body sites for testing, and a summary of methods for measuring physiological and perception changes using psychological or psychophysical scaling procedures. Despite its advantage of more closely simulating the real wear condition, performing a subjective test is time-consuming and expensive. Its accuracy depends on the reliability of the assessors and the result may vary between assessors. Objective measurement might therefore provide an attractive alternative. In this study, details of objective instrumental measurements are summarised according to the technology applied, and include gravimetric, observation-based, optical, spectroscopic, electrical, pressure-based, magnetic resonance and temperature detection methods. The principles, advantages and limitations of each method are systematically compared and discussed. Practical recommendations are proposed, particularly for enhancing the accuracy, reproducibility and/or simplicity of the methods. The objective of this review is to present an overview of various measurement methods, both subjective and objective. It is intended to form a basis for enabling fabric engineers to choose the most suitable analytical test method(s) when developing new fabric products with respect to performance, the availability of resources, time for testing, the type of fabrics to be tested and the accuracy and precision required. Additionally, the review points to the need for researchers to develop more advanced and accurate measurement methods to characterise the absorption and transport properties of fabrics.

Development of Calendula Oil/Chitosan Microcapsules and their Biological Safety Evaluation

Chitosan microcapsules containing calendula oil are prepared by a simple coacervation method. The results show that the performance of the microcapsules, including encapsulation efficiency and particle size, is affected by the change of various processing parameters of microcapsule manufacture. Under the optimal parameter combinations: the chitosan concentration is 1.5 % w/v; the core/wall ratio is 0.1 g mL–1; the stirring speed is 1200 rpm; and the pH value is 10. The compositions and surface morphology of the microcapsules are examined using scanning electron microscope and FTIR spectroscopy. The in vitro cytotoxicity evaluation demonstrates that the microcapsules exhibit no significant cytotoxic effects on human keratinocytes. The in vivo toxicology analysis on mice proves that the microcapsules do not exert any significant necrosis to the liver. It is suggested that our microcapsules could be used as a safe drug carrier both topically and orally.

Low stress mechanical properties of plasma-treated cotton fabric subjected to titanium dioxide coating

The titanium dioxide coating together with plasma pre-treatment improved the wrinkle recovery property of cotton fabrics, but, at the same time, may worsen the fabric handle which is an important factor when designing the end uses of fabric, as handle of fabric is also a critical factor for purchasing decisions. In this study, the Kawabata Evaluation System for Fabrics measures the sensory properties of plasma- and/or titanium dioxide-treated cotton fabrics. The low stress fabric surface correlates closely with mechanical properties; the change in fabric stiffness, thickness, extensibility, appearance retention, surface smoothness or bulkiness may affect each other. The results found that the titanium dioxide treatment had a negative effect on tensile properties, compressional properties and surface friction and variation, while shearing and bending properties were improved by the treatment. In addition, plasma treatment improves all sensory properties except surface friction and variation.The titanium dioxide coating together with plasma pre-treatment improved the wrinkle recovery property of cotton fabrics, but, at the same time, may worsen the fabric handle which is an important factor when designing the end uses of fabric, as handle of fabric is also a critical factor for purchasing decisions. In this study, the Kawabata Evaluation System for Fabrics measures the sensory properties of plasma- and/or titanium dioxide-treated cotton fabrics. The low stress fabric surface correlates closely with mechanical properties; the change in fabric stiffness, thickness, extensibility, appearance retention, surface smoothness or bulkiness may affect each other. The results found that the titanium dioxide treatment had a negative effect on tensile properties, compressional properties and surface friction and variation, while shearing and bending properties were improved by the treatment. In addition, plasma treatment improves all sensory properties except surface friction and variation.

Wrinkle-resistant finishing with dimethyloldihydroxyethyleneurea (DMDHEU) — the effect of co-catalyst

In the past, wrinkle-resistant finishes on cotton fabrics involved the application of melamine—formaldehyde- or urea— formaldehyde-based resins with many more recent agents being based on dimethylo...In the past, wrinkle-resistant finishes on cotton fabrics involved the application of melamine—formaldehyde- or urea— formaldehyde-based resins with many more recent agents being based on dimethyloldihydroxyethyleneurea (DMDHEU). This study reports that the DMDHEU—TiO2 combination can enhance the wrinkle-resistance of cotton fabrics. The addition of TiO2 or nano-TiO2 in the treatment can also act as a multi-functional finishing agent to improve the UV protection property. Moreover, it was found that addition of TiO 2 or nano-TiO2 could slightly increase the tearing strength of test specimens to compensate for the drawbacks of DMDHEU. However, the addition of metal oxide did not significantly improve the tensile strength of specimens. In addition, it was found that while DMDHEU-treated cotton specimens contained small quantities of free formaldehyde, these levels are reduced when nano-TiO2 is added to the treatment.