Multi-jet electrospinning of polystyrene/polyamide 6 blend: thermal and mechanical properties

Citation: Yoon, J. W., Park, Y., Kim, J., & Park, C. H. (2017). Multi-jet electrospinning of polystyrene/polyamide 6 blend: thermal and mechanical properties. Fashion and Textiles, 4, 12. doi:10.1186/s40691-017-0090-4Polystyrene (PS) has high thermal resistance thus can be applied as thermally comfortable textile. However, the application is limited due its low mechanical strength. In this study, polyamide 6 (PA6) was blended with PS to improve the mechanical strength of PS, by means of a multi-jet electrospinning. Content ratio of the blend web was measured by chemical immersion test and confocal microscopy analysis. Fiber content was in accordance with the number of syringes used for PS and PA6 respectively. The effects of content ratio on the web morphology, thermal resistance, tensile behavior, air and water vapor permeability, and surface hydrophilicity were investigated. The influence of environmental humidity during electrospinning process on three dimensional (3D) web structure was also reported. PS web produced from higher humidity had more pores and corrugations at the surface. The increased surface roughness and porosity led to the increased hydrophobicity and thermal resistance. Though the blending of PA6 with PS enhanced the mechanical strength, the added PA6 decreased air/water vapor permeability and thermal resistance. The lowered thermal resistance by the addition of PA6 was mainly attributed to higher thermal conductivity of PA6 material and lowered air content with PA6 fibers

Inscribing or Circumscribing a Histogon to a Convex Polygon

We consider two optimization problems of approximating a convex polygon, one by a largest inscribed histogon and the other by a smallest circumscribed histogon. An axis-aligned histogon is an axis-aligned rectilinear polygon such that every horizontal edge has an integer length. A histogon of orientation ? is a copy of an axis-aligned histogon rotated by ? in counterclockwise direction. The goal is to find a largest inscribed histogon and a smallest circumscribed histogon over all orientations in [0,?). Depending on whether the horizontal width of a histogon is predetermined or not, we consider several different versions of the problem and present exact algorithms. These optimization problems belong to shape analysis, classification, and simplification, and they have applications in various cost-optimization problems

Treatment of Branch Retinal Artery Occlusion With Transluminal Nd:YAG Laser Embolysis

The purpose of this paper was to report a successful treatment of transluminal Nd:YAG laser embolysis (NYE) for branch retinal artery occlusion (BRAO) with visible emboli. Two patients with acute, severe vision loss secondary to a branch retinal artery occlusion with visible emboli in one eye underwent NYE. A complete ocular examination was performed which included biomicroscopy of the posterior pole of the retina, intraocular pressure measurement, fundus color photographs, and fluorescein angiography (FA). After the NYE, the two patients showed dramatic improvements in best-corrected visual acuity, as well as, immediate and dramatic restorations in flow past the obstructed arteriole in FA. NYE is a treatment modality to be considered in patients with BRAO who present acutely with severe vision loss and a visible embolus

Green Tea Consumption and Stomach Cancer Risk: A Meta-Analysis

OBJECTIVES: Green tea has been suggested to have a chemopreventive effect against various cancers including stomach cancer. The aim of this study is to elucidate the relationship between green tea consumption and stomach cancer risk by meta-analysis. METHODS: Eighteen observational studies were identified using MEDLINE, THE COCHRANE LIBRARY, RISS, and a manual search. Summary relative risks/odds ratios (RR/ORs) for the highest versus non/lowest green tea consumption levels were calculated on the basis of fixed and random effect models. Subgroup analyses were used to examine heterogeneity across the studies. RESULTS: The combined results indicate a reduced risk of stomach cancer with intake of green tea (RR/OR=0.86, 95% CI=0.74-1.00). Subgroup analysis with six studies that reported differences between the highest and lowest consumption levels equal to or greater than five cups/day revealed a statistically significant protective effect (RR/OR=0.68, 95% CI=0.53-0.87). CONCLUSION: Green tea appears to play a protective role against the development of stomach cancer. The results also suggest that a higher level of green tea consumption might be needed for a clear preventive effect to appear. This conclusion, however, should be interpreted with caution because various biases can affect the results of a meta-analysis.ope

Progression from Chronic Atrophic Gastritis to Gastric Cancer; Tangle, Toggle, Tackle with Korea Red Ginseng

Key molecular players that link inflammation to carcinogenesis are prostaglandins, cytokines, nuclear factor-κB (NF-κB), chemokines, angiogenic growth factors, and free radicals, all of which lead to increased mutations and altered functions of important enzymes and proteins, for example, activation of oncogenic products and/or inhibition of tumor suppressor proteins, in inflamed tissues, thus contributing to multi-stage carcinogenesis process. Interpreted reversely, the identification of the molecular mechanisms by which chronic inflammation increases cancer risk or optimal intervention of targeted drugs or agents during the inflammation-associated carcinogenic process could be a necessary basis for developing new strategy of cancer prevention at many sites. In this review, we discuss the possibilities for cancer prevention by controlling inflammation process in Helicobacter pylori (H. pylori)-associated inflamed stomach with Korea red ginseng. Korea red ginseng is a good example of a natural herb that has ubiquitous properties that are conductive to stop inflammatory carcinogenesis that is un wanted outcome of H. pylori infection, rendering rejuvenation of chronic atrophic gastritis

Suppression of Structural Fatigue by Doping in Spinel Electrode Probed by In Situ Bending Beam Method

The onset of a Jahn-Teller effect at the surface of LiMn2O4 particles during cycling in the 4 V range was previously reported to be one of the causes for the capacity fading. Furthermore, it has been reported that the Jahn-Teller effect in the 4 V range may be suppressed by the substitution of the Mn ions by either Li or other transition metal ions. However, no direct evidence has yet been reported. This study provides evidence for the onset of a Jahn-Teller effect in thin film 4 V LiMn2O4 and its suppression caused by substituting the Mn ions with Co31 and Ni21 ions using in situ bending beam method ~BBM!. The deflectograms are measured simultaneously with galvanostatic charge/discharge or cyclic voltammograms, and the onset of the Jahn-Teller effect is investigated by means of the differential strain peak which is observed at around 3.90-3.95 V during cyclic voltammetry, and the slope variation observed in the strain curves during galvanostatic charge/discharge. The suppression of the Jahn-Teller effect in the doped spinel leads to the magnitude of the differential strain peak resulting from the Jahn-Teller effect being reduced in comparison with the other two pairs of peaks, which correspond to the current peaks of the cyclic voltammogram.This work was supported by KOSEF through the Research Center for Energy Conversion and Storage (RCECS), Korea Science and Engineering Foundation (no. 2000-2-30100-012-3) and by the Ministry of Information and Communication of Korea (Support Project of University Information Technology Research Center supervised by KIPA). The authors thank Cheil Industries, Inc., for the supporting electrolytes

Oxygen Partial Pressure during Pulsed Laser Deposition: Deterministic Role on Thermodynamic Stability of Atomic Termination Sequence at SrRuO3/BaTiO3 Interface

With recent trends on miniaturizing oxide-based devices, the need for atomic-scale control of surface/interface structures by pulsed laser deposition (PLD) has increased. In particular, realizing uniform atomic termination at the surface/interface is highly desirable. However, a lack of understanding on the surface formation mechanism in PLD has limited a deliberate control of surface/interface atomic stacking sequences. Here, taking the prototypical SrRuO3/BaTiO3/SrRuO3 (SRO/BTO/SRO) heterostructure as a model system, we investigated the formation of different interfacial termination sequences (BaO-RuO2 or TiO2-SrO) with oxygen partial pressure (PO2) during PLD. We found that a uniform SrO-TiO2 termination sequence at the SRO/BTO interface can be achieved by lowering the PO2 to 5 mTorr, regardless of the total background gas pressure (Ptotal), growth mode, or growth rate. Our results indicate that the thermodynamic stability of the BTO surface at the low-energy kinetics stage of PLD can play an important role in surface/interface termination formation. This work paves the way for realizing termination engineering in functional oxide heterostructures.Comment: 27 pages, 6 figures, Supporting Informatio

Anticancer Effect of Nemopilema nomurai

Various kinds of animal venoms and their components have been widely studied for potential therapeutic applications. This study evaluated whether Nemopilema nomurai jellyfish venom (NnV) has anticancer activity. NnV strongly induced cytotoxicity of HepG2 cells through apoptotic cell death, as demonstrated by alterations of chromatic morphology, activation of procaspase-3, and an increase in the Bax/Bcl-2 ratio. Furthermore, NnV inhibited the phosphorylation of PI3K, PDK1, Akt, mTOR, p70S6K, and 4EBP1, whereas it enhanced the expression of p-PTEN. Interestingly, NnV also inactivated the negative feedback loops associated with Akt activation, as demonstrated by downregulation of Akt at Ser473 and mTOR at Ser2481. The anticancer effect of NnV was significant in a HepG2 xenograft mouse model, with no obvious toxicity. HepG2 cell death by NnV was inhibited by tetracycline, metalloprotease inhibitor, suggesting that metalloprotease component in NnV is closely related to the anticancer effects. This study demonstrates, for the first time, that NnV exerts highly selective cytotoxicity in HepG2 cells via dual inhibition of the Akt and mTOR signaling pathways, but not in normal cells