GLOBAL SOLUTIONS OF NONLINEAR TRANSPORT EQUATIONS FOR CHEMOSENSITIVE MOVEMENT

A widespread phenomenon in moving microorganisms and cells is their ability to reorient themselves depending on changes of concentrations of certain chemical signals. In this paper we discuss kinetic models for chemosensitive movement, which also takes into account evaluations of gradient fields of chemical stimuli which subsequently influence the motion of the respective microbiological species. The basic type of model was discussed by Alt [J. Math. Biol., 9 (1980), pp. 147-177], [J. Reine Angew. Math., 322 (1981), pp. 15-41] and by Othmer, Dunbar, and Alt [J. Math. Biol., 26 (1988), pp. 263-298]. Chalub et al. rigorously proved that, in three dimensions, these kinds of kinetic models lead to the classical Keller-Segel model as its drift-diffusion limit when the equation for the chemo-attractant is of elliptic type [Monatsh. Math., 142 (2004), pp. 123-141], [On the Derivation of Drift-Diffusion Model for Chemotaxis from Kinetic Equations, ANUM preprint 14/02, Vienna Technical University, 2002]. In [H. Hwang, K. Kang, and A. Stevens, Drift-diffusion limits of kinetic models for chemotaxis: A generalization, Discrete Contin. Dyn. Syst. Ser. B., to appear] it was proved that the macroscopic diffusion limit exists in both two and three dimensions also when the equation of the chemo-attractant is of parabolic type. So far in the rigorous derivations, only the density of the chemo-attractant was supposed to influence the motion of the chemosensitive species. Here we show that in the macroscopic limit some types of evaluations of gradient fields of the chemical stimulus result in a change of the classical parabolic Keller-Segel model for chemotaxis. Under suitable structure conditions, global solutions for the kinetic models can be shown.open1128Nsciescopu

Synthesis of highly elastic biocompatible polyurethanes based on bio-based isosorbide and poly(tetramethylene glycol) and their properties.

Bio-based high elastic polyurethanes were prepared from hexamethylene diisocyanate and various ratios of isosorbide to poly(tetramethylene glycol) as a diol by a simple one-shot bulk polymerization without a catalyst. Successful synthesis of the polyurethanes was confirmed by Fourier transform-infrared spectroscopy and (1)H nuclear magnetic resonance. Thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis. The glass transition temperature was -47.8℃. The test results showed that the poly(tetramethylene glycol)/isosorbide-based elastomer exhibited not only excellent stress-strain properties but also superior resilience to the existing polyether-based polyurethane elastomers. The static and dynamic properties of the polyether/isosorbide-based thermoplastic elastomer were more suitable for dynamic applications. Moreover, such rigid diols impart biocompatible and bioactive properties to thermoplastic polyurethane elastomers. Degradation tests performed at 37℃ in phosphate buffer solution showed a mass loss of 4-9% after 8 weeks, except for the polyurethane with the lowest isosorbide content, which showed an initial rapid weight loss. These polyurethanes offer significant promise due to soft, flexible and biocompatible properties for soft tissue augmentation and regeneration

Effect of liquid spreading due to nano/microstructures on the critical heat flux during pool boiling

It is well known that nanoparticles deposited on a heating surface during nanofluid boiling can change the characteristics of the heating surface and increase the critical heat flux (CHF) dramatically. We considered a new approach to investigate the nanoparticle surface effect on CHF enhancement using surfaces modified with artificial micro/nanostructures similar to deposited nanoparticle structures. We examined the effect of the surface wettability and liquid spreading ability on the CHF. The results demonstrated that the CHF enhancement on the modified surfaces was a consequence of both the improved surface wettability and the liquid spreading ability of the artificial micro/nanostructures. © 2011 American Institute of Physics.open11102116Nsciescopu

Comparison of Stemness and Gene Expression between Gingiva and Dental Follicles in Children

published_or_final_versio

Patterning of ferroelectric nanodot arrays using a silicon nitride shadow mask

We grew well-ordered arrays of ferroelectric Pb (Zr0.2 Ti0.8) O3 (PZT) nanodots on a SrRu O3 SrTi O3 substrate by pulsed laser deposition. A silicon nitride shadow mask with ordered holes was used for patterning of the PZT arrays. Each dot has a height of ???15 nm and a diameter of ???120 nm with a similar dome shape over a large area. The ferroelectric properties of individual PZT dots were investigated by piezoresponse force microscopy. A single dot could be polarized individually and the polarized state remained unrelaxed to ???20 min.open232

Antipruritic Effect of Acupuncture in Patients with Atopic Dermatitis: Feasibility Study Protocol for a Randomised, Sham-Controlled Trial

© 2017 Yu-Kang Kim et al. This study aims to test the feasibility of a randomised clinical trial to evaluate how acupuncture affects atopic dermatitis (AD) symptoms and quality of life and to explore potential biomarkers that may be associated with AD. It is a sham-controlled trial in which 30 eligible patients will be randomly allocated in a 1: 1: 1 ratio to one of three groups: Verum acupuncture (VA) group 1 (3 times weekly for 4 weeks); VA group 2 (twice weekly for 4 weeks); or sham acupuncture group (SA; twice weekly for 4 weeks). SA will consist of nonpenetrating acupuncture. Outcome measures will include the Visual Analogue Scale for itch, SCORing Atopic Dermatitis, and Eczema Area and Severity Index to evaluate AD symptoms improvement along with the Patient Oriented Eczema Measure and Dermatology Life Quality Index to assess quality of life. Measures will be collected at baseline, once weekly during the treatment period, and after a 4-week follow-up period. Blood collection will be at baseline and 4 and 8 weeks after treatment and compared with healthy controls. Illumina sequencing will be used to profile microRNA expression in each group to explore candidate microRNA biomarkers for specific effects of acupuncture in patients with AD. This trial is registered via US National Institutes of Health Clinical Trials registry (ClinicalTrials.gov) on 15 July 2016, identifier: NCT02844452

Nonlinear oscillations of a sessile drop on a hydrophobic surface induced by ac electrowetting

We examine the nature of ac electrowetting (EW)-driven axisymmetric oscillations of a sessile water drop on a dielectric substrate. In ac EW, small-amplitude oscillations of a drop differ from the Rayleigh linear modes of freely oscillating drops. In this paper, we demonstrate that changes in the time-averaged contact angle of the sessile drop attributed to the presence of an electric field and a solid substrate mainly caused this discrepancy. We combine the domain perturbation method with the Lindsted-Poincare method to derive an asymptotic formula for resonant frequency. Theoretical analysis shows that the resonant frequency is a function of the time-averaged contact angle. Each mode of the resonance frequency is a linear function of epsilon(1), which is the magnitude of the cosine of the time-averaged contact angle. The most dominant mode in this study, that is, the fundamental mode n = 2, decreases linearly with epsilon(1). The results of the theoretical model are compared with those of both the experiments and numerical simulations. The average resonant frequency deviation between the perturbation solutions and numerical simulations is 4.3%, whereas that between the perturbation solutions and the experiments is 1.8%.ope

Impact of visceral fat on skeletal muscle mass and vice versa in a prospective cohort study: The Korean Sarcopenic Obesity Study (KSOS)

Objectives: Sarcopenia and visceral obesity have been suggested to aggravate each other, resulting in a vicious cycle. However, evidence based on prospective study is very limited. Our purpose was to investigate whether visceral fat promotes a decrease in skeletal muscle mass and vice versa. Methods: We observed changes in anthropometric and body composition data during a follow-up period of 27.6±2.8 months in 379 Korean men and women (mean age 51.9±14.6 years) from the Korean Sarcopenic Obesity Study (KSOS). Appendicular lean soft tissue (ALST) mass was calculated using dual-energy X-ray absorptiometry, and visceral fat area (VFA) was measured using computed tomography at baseline and follow-up examination. Results: ALST mass significantly decreased, whereas trunk and total fat mass increased in both men and women despite no significant change in weight and body mass index. In particular, women with visceral obesity at baseline had a greater decrease in ALST mass than those without visceral obesity (P=0.001). In multiple linear regression analysis, baseline VFA was an independent negative predictor of the changes in ALST after adjusting for confounding factors including age, gender, life style and body composition parameters, insulin resistance, high sensitivity C-reactive protein and vitamin D levels (P=0.001), whereas the association between baseline ALST mass and changes in VFA was not statistically significant (P=0.555). Conclusions: This longitudinal study showed that visceral obesity was associated with future loss of skeletal muscle mass in Korean adults. These results may provide novel insight into sarcopenic obesity in an aging society