The Use of Nanoscale Visible Light-Responsive Photocatalyst TiO2-Pt for the Elimination of Soil-Borne Pathogens

Exposure to the soil-borne pathogens Burkholderia pseudomallei and Burkholderia cenocepacia can lead to severe infections and even mortality. These pathogens exhibit a high resistance to antibiotic treatments. In addition, no licensed vaccine is currently available. A nanoscale platinum-containing titania photocatalyst (TiO2-Pt) has been shown to have a superior visible light-responsive photocatalytic ability to degrade chemical contaminants like nitrogen oxides. The antibacterial activity of the catalyst and its potential use in soil pathogen control were evaluated. Using the plating method, we found that TiO2-Pt exerts superior antibacterial performance against Escherichia coli compared to other commercially available and laboratory prepared ultraviolet/visible light-responsive titania photocatalysts. TiO2-Pt-mediated photocatalysis also affectively eliminates the soil-borne bacteria B. pseudomallei and B. cenocepacia. An air pouch infection mouse model further revealed that TiO2-Pt-mediated photocatalysis could reduce the pathogenicity of both strains of bacteria. Unexpectedly, water containing up to 10% w/v dissolved soil particles did not reduce the antibacterial potency of TiO2-Pt, suggesting that the TiO2-Pt photocatalyst is suitable for use in soil-contaminated environments. The TiO2-Pt photocatalyst exerted superior antibacterial activity against a broad spectrum of human pathogens, including B. pseudomallei and B. cenocepacia. Soil particles (<10% w/v) did not significantly reduce the antibacterial activity of TiO2-Pt in water. These findings suggest that the TiO2-Pt photocatalyst may have potential applications in the development of bactericides for soil-borne pathogens

Synthesis of All-Conjugated Block Copolymers PPP-P3HT by Using Grignard Metathesis and Study of Copolymer Blending with C60 Derivatives PCBM/ICBA: Hybrid Morphology, Optoelectronic Property and Solar Cell Application

含有共軛鏈段之團聯共聚高分子由於本身具備的自組裝特性可進而有效藉由結構上的改變來調控其機械與光電特性，因而逐漸受到各界廣泛的注意。因此，瞭解此類含有共軛鏈段之團聯共聚高分子其自組裝特性以利後續的應用發展乃是相當重要的一環。然而目前在此研究課題上仍有許多未知的現象有待探索。在本論文中提到利用格林納聚合法一系列的PPP-P3HT雙共軛團聯共聚高分子已被成功的合成出來，並同時固定PPP練段長度進而改變P3HT分子量,一系列高分子與單體經NMR與GPC鑑定。 將高分子與碳六十衍生物PCBM/ICBA在不同溶劑下可得到不同的形態與光學性質，並經由各式儀器逕行分析，像是UV-Vis光譜，PL光譜，及XRD，TEM等等。藉由高分子PPP-P3HT之自組裝，可有效分散PCBM，同時ICBA的分散性也比PCBM好。此外，可利用選擇溶劑和製成方法的不同而改變PCBM分布之區域在PPP或是P3HT中，而ICBA在block copolymers的光電轉換效率可達2%，然而我們亦注意到團聯共聚合物混摻PCBM奈米有機物後對於發光有一quench效果，主因是由於高分子受到光激發後電子與電洞經由PPP-P3HT/PCBM混成系統的能階傳導造成之電荷分離效應所致。最後在太陽能元件效率上已可達到3.5%，因此在未來的應用上具有非常大的潛力。In this study, all-conjugated rod-rod poly(2,5-dihexyloxy-p-phenylene)- b-poly(3-hexylthiophene) (PPP-P3HT) block copolymers with different block ratio between PPP and P3HT were synthesized and their self-assembly behavior was investigated. A series of monodisperse PPP-P3HT block copolymers consisting of a nearly constant molecular weight PPP block and a different molecular weight P3HT block was synthesized via a sequential Grignard metathesis method (GRIM). Gel permeation chromatographer, NMR spectra and transmission electron microscopy were used to characterize the block copolymers. The blending system of PPP-P3HT and PCBM/ICBA was made using different solvents such as dichlorobenzene and toluene followed by drop-casting/spin-coating the resulting solutions for the fabrication of PPP-P3HT/PCBM or PPP-P3HT/ICBA thin films. These systems afford different properties, such as morphology and optical properties. In addition, the morphology, thermal and optoelectronic properties of the blending system were studied by using FTIR, UV-VIS, XRD, photoluminescence spectroscopy and transmission electron microscopy. We find that the aggregation of polymer blending PCBM can be dispersed by the self-assembly of PPP-P3HT and the dispersion of PPP-P3HT/ICBA is better than the PPP-P3HT/PCBM in ODCB solvent. Besides, The existence domain of PCBM in PPP or P3HT can be controlled by the used solvents and fabrication in the blending system of PPP-P3HT and PCBM. the Incident Photon Conversion Efficiency in the PPP-P3HT block copolymers blending with ICBA can be performed up to 2.0%, and the solar cell performance of PPP-P3HT/PCBM films was investigated. The best efficiency is 3.50%

Targeting buyers of counterfeits of luxury brands: a study on attitudes of Singapore consumers

The paper examines the factors that influence Singaporean consumer's attitudes towards counterfeits of luxury brands. Data was collected from a convenience sample of postgraduate students of a large university using a self-administered questionnaire. Social influence, brand consciousness and price quality inference were found to significantly influence attitudes towards counterfeits of luxury brands. There is no significant relationship with personal gratification, value consciousness, and brand prestige. Attitudes towards counterfeits of luxury brands were found to influence purchase intention