Jun-Yan Hu

Development of Fe3O4-poly(L-lactide) magnetic microparticles in supercritical CO2.

The Fe(3)O(4)-poly(L-lactide) (Fe(3)O(4)-PLLA) magnetic microparticles were successfully prepared in a process of solution-enhanced dispersion by supercritical CO(2) (SEDS), and their morphology, particle size, magnetic mass content, surface atom distribution and magnetic properties were characterized. Indomethacin (Indo) was used as a drug model to produce drug-polymer magnetic composite microparticles. The resulting Fe(3)O(4)-PLLA microparticles with mean size of 803 nm had good magnetic property and a saturation magnetization of 24.99 emu/g. The X-ray photoelectron spectroscopy (XPS) test indicated that most of the Fe(3)O(4) were encapsulated by PLLA, which indicated that the Fe(3)O(4)-PLLA magnetic microparticles had a core-shell structure. After further loading with drug, the Indo-Fe(3)O(4)-PLLA microparticles had a bigger mean size of 901 nm, and the Fourier transform infrared spectrometer (FTIR) analysis demonstrated that the SEDS process was a typical physical coating process to produce drug-polymer magnetic composite microparticles, which is favorable for drugs since there is no change in chemistry. The in vitro cytotoxicity test showed that the Fe(3)O(4)-PLLA magnetic microparticles had no cytotoxicity and were biocompatible, which means there is potential for biomedical application.

A 5-fluorouracil-loaded polydioxanone weft-knitted stent for the treatment of colorectal cancer

In-stents restenosis caused by tumour ingrowth is a major problem for patients undergoing stent displacement because the conventional stents often lack a sustained anti-tumour capability. The aim of this paper was to develop a weft-knitted polydioxanone stent which can slow release 5-fluorouracil (5-FU). In order to determine the most suitable drug concentration, the 5-FU safe concentration in vivo and appropriate loading percentage in the membranes were investigated, and then 5-FU-loaded poly-l-lactide membranes at concentration of 3.2%, 6.4% and 12.8% were coated onto the stent using electro-spinning method, respectively. The morphology, chemical structure and in vitro drug release property of the coating membranes were subsequently examined. Their anti-tumour activity and mechanism were assessed in vitro and in vivo using a human colorectal cancer cell line HCT-116 and tumour-bearing BALB/c nude mice. The half maximal inhibitory concentration (IC50) and the median lethal dose (LD50) demonstrated that the 6.4% and 12.8% membranes had better anti-tumour effects than pure 5-FU due to the sustainable drug releasing property of the coated membranes on the stent. The membranes possessing appropriate drug loading doses, such as 6.4% or 12.8% also provided better anti-in-stents restenosis effects than other groups tested. Therefore, it is concluded that the drug-loaded stents have great potential for the use in the treatment of intestinal cancers in the future.

A simultaneous measurement method to characterize touch properties of textile materials

Touch feels of textile materials are major factors related to the clothing comfort. We could perceive touch feels through contacts between skin and fabrics. Latest researches concluded there were four types of touch information including thermal, proprioceptive, cutaneous, and irritant and pains. There is a clear gap between current measurement methods on fabric touch feels and latest theoretical research outputs. This report introduced a new characterization method of textile touch feels. It simultaneously measured four categories of physical properties of textiles. Fabric Touch Tester (FTT), the reported instrument, included four modules as thermal, compression, bending and surface. Measuring time of one complete test on this instrument only took about 5 minutes. Output of FTT contained comprehensive descriptions on the physical properties of samples in both directions (warp/wale and weft/course). Experiment results showed that FTT could measure and distinguish these fabrics with good repeatability and reproducibility. Correlation study between FTT results and subjective evaluation scores showed there were significant correlations between them. Initial findings were concluded on the effect of thermal properties on other tactile perceptions as well as the interactions between different physical parameters.

Synthesis and characterization of wool keratin/hydroxyapatite nanocomposite

Taking the inspiration from the biomineral, the wool keratin was selected to modulate the assembly of nanosized hydroxyapatite (HA) crystals via a coprecipitation method. A series of keratin/HA nanocomposite with different ratios were synthesized by adjusting the concentrations of keratin solutions and calcium phosphate and their final components were detected by thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed that keratin in the composite decreased the crystallinity of HA. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to examine the chemical and surface structure of the composites. In vitro biocompatibility results revealed that cells showed better viability on keratin/HA composites which have a ratio of organics and inorganics similar to that of natural bones.

Effects of fabrics with dynamic moisture transfer properties on skin temperature in females during exercise and recovery

Based on the physiological nature of breast movement in exercising females, a sports bra made of fabric with dynamic moisture transfer properties was developed to improve female thermal comfort. This study aimed to investigate the effects of fabrics with dynamic moisture transfer properties on breast skin temperature, and the thermal physiological and psychological response of women while wearing the sports bra during exercise and recovery. Ten healthy women exercised in random order with two types of sports bra with or without the dynamic moisture transfer properties and then performed a 20-minute short-duration high-intensity exercise and rest to recover under thermoneutral conditions. Heart rate, body core temperature, skin temperature, body mass and thermal psychological subjective sensations were investigated during exercise and recovery. The results indicated that in the running state, the local breast skin temperatures of sports bra made of fabrics with dynamic moisture transfer properties (33.427 ± 0.087℃) are significantly lower than bras without these dynamic moisture transfer properties (33.964 ± 0.055℃) (P < 0.01). During the exercise and recovery, the thermal psychological subjective sensation for the two types of fabrics were very similar, whereas the body mean skin temperature was revealed to undergo greater decreasing effects in sports bras made of fabrics with dynamic moisture transfer properties than those without the dynamic moisture transfer properties (P < 0.05). These results provide novel information that usage of fabrics with dynamic moisture properties in sports bras could improve thermoregulation to benefit exercising women’s thermal comfort in terms of decreasing local breast skin temperature.

Smart moisture management and thermoregulation properties of stimuli-responsive cotton modified with polymer brushes

Thermoresponsive PNIPAM polymer brushes are grafted onto the surface of cotton fabrics to construct a smart hierarchical system. The smart system exhibits thermoregulation by responsively absorbing perspiration at different atmospheric temperatures.

An optimized design of compression sportswear fabric using numerical simulation and the response surface method

Well-designed compression sportswear can be used for the enhancement of athletic performance and reduction of injury. The material and geometric properties of fabric for compression sportswear are vital in achieving compression effects. This study evaluated and optimized the performance of fabric using the design of experiment (DOE) methods, the response surface method (RSM) and the finite element (FE) model. The evaluation and optimization procedure consisted of three phases. The first phase involved developing the FE model of a fabric tube and cylinder, and validated it by compression experiments involving different fabrics. The second phase evaluated the FE prediction using a five-factor experimental design, namely, hyperelastic properties, thickness, density, friction, and tensile strain. The third and final phase was an optimization process using RSM based on the evaluation results. Findings show that the FE predictions approach closely the results of validation experiments. The nonlinear elastic material properties (hyperelastic properties) and shape dimensions (thickness and tensile strain) of fabric tube were found to be important design factors in influencing contact pressure, while the density of fabric and interface friction coefficient played less important roles. The optimal FE model was determined using RSM analysis. The statistically based FE model was found to be an effective approach for evaluating and optimizing the design parameters of fabric for compression sportswear. The results can be applied to make sportswear that has different compression effects at selected anatomical locations to enhance performance and reduce injuries.

Clothing Expenditure and the Income Elasticity of Chinese Consumers

In this paper, the clothing expenditure and income elasticity of Chinese consumers are investigated by analyzing the clothing expenditure and income in average households during the past 11 years, their geographic distribution in 1996, and their variation in urban households with different incomes. From these analyses, we can conclude that the consumptive power of Chinese consumers has increased considerably over the past 11 years, as shown from their steadily increasing income, total expenditure, and clothing expenditure. However, as their income increases, Chinese consumers tend to spend proportionally less money on clothing, in both urban and rural households. Investigating the geographic distribution of income, clothing expenditure, Gross Domestic Product (GDP), and climatic temperature, we find that income and climatic temperature are important variables determining the clothing expenditure of urban and average households, while income, GDP, and climatic temperature have almost equal contributions to...

The mechanics of buckling fiber in relation to fabric‐evoked prickliness: a theory model of single fiber prickling human skin

The simple Euler model of buckling of a slender rod has been commonly used to explain the mechanics in relation to the buckling of fabric‐evoked prickliness. Unfortunately, few works have paid attention to its applicability into the buckling behavior of fiber prickling human skin to evoke prickliness, though the friction between the fiber end and the skin and the firmness of a fiber end held in fabric (denoted as elastic stiffness) are considered to be among the main factors for fabric‐evoked prickliness. To model the mechanics of buckling of a fiber in relation to fabric‐evoked prickliness, the fiber–skin friction, the elastic stiffness, and the initial inclined angle of the fiber are introduced into the simple Euler model of buckling of a slender rod. Then, a sensitivity analysis is performed on these three factors to observe their role in the buckling behavior of a fiber. The results demonstrate that the fiber–skin friction and the elastic stiffness have a significant effect on the buckling behavior of fiber end prickling skin and the stimulus intensity to skin. Additionally, the fiber with an initial inclined angle can exert compression force on skin above the average force threshold of nociceptors responsible for fabric‐evoked prickliness, and the force size depends on the fiber property and its end‐restraint intensity. Therefore, it is not appropriate for the assumption of a fixed‐hinged boundary of the fiber end prickling human skin. In this sense, a developed fiber–skin coupling model provides a good modeling for the buckling behavior of fiber end pricking human skin.

Effects of body-mapping-designed clothing on heat stress and running performance in a hot environment

Abstract To investigate clothing-induced differences in human thermal response and running performance, eight male athletes participated in a repeated-measure study by wearing three sets of clothing (CloA, CloB, and CloC). CloA and CloB were body-mapping-designed with 11% and 7% increased capacity of heat dissipation respectively than CloC, the commonly used running clothing. The experiments were conducted by using steady-state running followed by an all-out performance running in a controlled hot environment. Participants’ thermal responses such as core temperature (Tc), mean skin temperature (), heat storage (S), and the performance running time were measured. CloA resulted in shorter performance time than CloC (323.1 ± 10.4 s vs. 353.6 ± 13.2 s, p = 0.01), and induced the lowest , smallest ΔTc, and smallest S in the resting and running phases. This study indicated that clothing made with different heat dissipation capacities affects athlete thermal responses and running performance in a hot environment. Practitioner Summary: A protocol that simulated the real situation in running competitions was used to investigate the effects of body-mapping-designed clothing on athletes’ thermal responses and running performance. The findings confirmed the effects of optimised clothing with body-mapping design and advanced fabrics, and ensured the practical advantage of developed clothing on exercise performance.