A vertical sweating skin model is developed and changes in vapor pressure within a clothing system are measured to investigate the effects of fiber type, air layer thickness, and garment openings on the microclimate. Cotton broadcloth, polyester broadcloth and cotton canvas are considered. Openings of a garment, such as neck, armhole and waist, are simulated, and the total openness is controlled at 0, 10, 20, 40, and 60%. To evaluate changes in the microclimate of the clothing system, a buffering index Kd and the efficiency of openness are determined. Results show that the buffering index of polyester is higher than that of cotton. As the thickness of the air layer increases, the buffering index increases but an unnecessarily large air gap does not increase the buffering capacity efficiently. As the openness increases, the effect of fabrics on the microclimate decreases gradually, losing its effect at 60% and approached the value of nude skin.

Thermal degradation of vegetable-tanned leather fiber (VLF) was investigated by thermogravimetric analysis aiming to know the exact kinetics and degradation mechanism. The thermogravimetric (TG) and differential thermogravimetric (DTG) curves showed that decomposition of the VLF occurs mainly in the range of 150-600°C, and the latter exhibits asymmetrical peak with a pronounced shoulder. The decomposition process was first analyzed by deconvolution of the experimental DTG curves, followed by reconstruction of the weight loss profiles of two individual processes. Several common isoconversional approaches were applied to calculate the activation energy over a wide range of conversion for the sample, including modified Kissinger-Akahira-Sunose (MKAS), Friedman, and Flynn-Wall-Ozawa. The average activation energy of vegetable-tanned leather fiber was found to be 241.9 kJ mol − 1 by MKAS method. The activation energy values obtained for the pseudocomponents representing highly-crosslinked and low-crosslinked collagen in VLF were given as 190.6 and 124.8 kJ mol − 1 , respectively. Generalized master plots results suggested that the reaction mechanism for highly-crosslinked collagen follows the random nucleation and growth process at conversion values lower than 0.5. When the conversion is higher than 0.5, the mechanism tends to random scission model. For low-crosslinked collagen, the degradation is mainly governed by random nucleation and nuclei growth. The gaseous products of VLF thermal degradation were analyzed with an online-coupled TG-Fourier transform infrared spectroscopy system.

Hydrogel is an ideal wound dressing material because of its 3D network structure, which is similar to that of the extracellular matrix. However, it is a challenge to design antibiotic-free hydrogels with both antibacterial activity and enhanced mechanical strength. In this study, a polyvinyl alcohol (PVA) hybrid hydrogel incorporated with molybdenum disulfide@polydopamine@silver (MoS 2 @PDA@Ag) is prepared for rapid killing of bacteria under irradiation with near-infrared (NIR) light. The interpenetration of MoS 2 -based nanoparticles and PVA molecular chain significantly improves the mechanical property of the hydrogel. The hydrogels demonstrate an excellent photothermal effect and antibacterial activity, and the photocatalytic properties are considerably enhanced by Ag doping. The hydrogel exhibits favorable antibacterial activity after irradiation with 808 nm NIR light for 15 min due to the synergistic effect of reactive oxygen species and hyperthermia. Meanwhile, in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay further demonstrated that all hydrogels are nontoxic when their effects are examined against mouse fibroblasts (L929) cells. In addition, the MoS 2 @PDA@Ag/PVA hydrogel can promote wound healing compared with the pure PVA hydrogel, demonstrating its significant potential in mitigating bacterial infection of wounds.

In this paper, we apply the least-squares method to estimate the unknown parameters in first-order random coefficient integer-valued autoregressive (RCINAR(1)) processes. The least-squares estimator is derived and its limiting properties are discussed. Furthermore, we also derive a statistic to test the randomness of coefficients. Numerical results from simulation studies suggest that the proposed method is good for practical use. MSC: Primary 62M10; secondary 62M05

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