Cu/CuO@ZnO Hollow Nanofiber Gas Sensor: Effect of Hollow Nanofiber Structure and P–N Junction on Operating Temperature and Sensitivity

For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the presence of 100 ppm CO gas, the Cu/CuO-photodeposited ZnO hollow nanofiber (Cu/CuO@ZnO HNF) showed twice higher sensitivity than that of pure ZnO nanofiber at a relatively low working temperature of 300◦ C. The hollow structure and p–n junction between Cu/CuO and ZnO would be considered to contribute to the enhancement of sensitivity to CO gas at 300◦ C due to the improved specific surface area and efficient electron transfer. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. T.1

KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model

AbstractKAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models

Barotraumatic Perforation of Pharyngoesophagus by Explosion of a Bottle into the Mouth

Pharyngoesophageal perforation from an exploding bottle is an extremely rare injury. To date, twenty-four cases have been documented in English literature. In this study, we reported two additional cases of pharyngoesophageal perforation by a bottle exploding in the mouth. Explosion of the bottle occurred when the patients removed the cap of a home-made wine bottle with their teeth, which resulted in pharyngoesophageal perforation. The patients were managed by conservative treatment and operative repair, respectively. Both patients had an uneventful recovery. Possible mechanisms and preventive measures are discussed in this study, along with a review of the literature

Occupational Hearing Loss in Korea

In this article, current status of noise exposure in workplaces, trend of workers with noise-induced hearing loss (NIHL), and prevalence of NIHL in workers by industry and job category in Korea were reviewed. In addition, trends of research on the audiological effects such as hearing loss from noise and occupational hearing loss from non-noise in Korea were addressed through reports in industrial audiology. Though noise exposure level has improved, noise still shows the highest rate of cases exceeding exposure limit among workplace hazards. NIHL is the most common occupational disease except work-related disease such as musculoskeletal disorders and cerebrovascular diseases, and NIHL prevalence is thought to be much higher than reported in official publications. Noise affecting hearing comes from various sources such as workplaces, military settings, areas with exposure to high noise, and specific noise sources. There is also occupational hearing loss by non-noise including chemicals such as organic solvents and heavy metals, barotrauma, and trauma due to welding spark. Noise affects daily life through audiological effects such as hearing loss and tinnitus, non-audiological physical effects (e.g., cardiovascular), and psychosocial and behavioral effects. Development of systematic and comprehensive hearing conservation programs for lowering the noise level in workplaces and preventing the NIHL, and preparation of technological, administrative system for its settlement at workplace are urgently needed

Preparation of TiO2-embedded carbon nanofibers and their photocatalytic activity in the oxidation of gaseous acetaldehyde

TiO2-embedded carbon nanofibers (TiO2/CNF) have been prepared by a simple method. TiO2-embedded polyacrylonitrile fibers (TiO2/PAN) were first prepared from a PAN solution containing TiO2 particles by a simple electrospinning method, and subsequent carbonization and further oxidation of these led to TiO2/CNF and oxidized TiO2/CNF (Ox-TiO2/CNF), respectively. Gaseous CH3CHO was efficiently degraded with the concomitant production of CO2 on the Ox-TiO2/CNF composites under UV illumination. Although UV-illuminated TiO2/PAN were also found to be capable of oxidizing gaseous CH3CHO, these fibers underwent slow but spontaneous degradation. On the other hand, TiO2/CNF had no effect on the photocatalytic oxidation of CH3CHO, which may be attributed to the reduction and phase transformation of TiO2 during carbonization. XPS results have shown that TiO2 was partly reduced by carbonization and then re-oxidized during the further oxidation process. No anatase phase of TiO2 was observed in the TiO2/CNF composites, whereas this phase was unequivocally observed in the Ox-TiO2/CNF composites. Moreover, the BET surface area was seen to be significantly enhanced by the further oxidation process, and this was responsible for the adsorption of CH3CHO on the Ox-TiO2/CNF. Therefore, the further oxidation process not only brings about re-oxidation of TiO2 but also leads to a surface modification of the carbon nanofibers. © 2008 Elsevier B.V. All rights reserved.1

Titania-coated plastic optical fiber fabrics for remote photocatalytic degradation of aqueous pollutants

Plastic optical fiber fabrics are widely utilized as efficient support materials owing to their high flexibility. In this study, we have investigated a remote photocatalysis system using modified plastic optical fiber fabrics. We successfully deposited TiO2 onto a modified plastic optical fiber fabric using the dip-coating method. The drying temperature was fixed at 50 °C in order to inhibit the decomposition of the fabric. The TiO2-coated woven plastic optical fiber fabric was applied to the photocatalytic degradation of methylene blue (MB) and the simultaneous oxidation of 4-chlorophenol (4-CP) and reduction of Cr(VI). The degradation of MB by direct photolysis, or through dark reactions of the adsorbed MB on the surface of the fabric, was not observed. MB degradation increased with increasing TiO2 loading, Pt deposition, increasing solution pH, and decreasing initial MB concentration. Repeated testing in the above-mentioned degradation and simultaneous redox reactions revealed that the TiO2-coated woven plastic optical fiber fabrics retain good activity after multiple cycles. On the basis of these results, we propose that plastic optical fiber fabrics together with photocatalysts are suitable for remote (in situ) advanced oxidation process useful for the remediation of contaminated soil or groundwater. © 2017 Elsevier Ltd. All rights reserved.1