On the association between outdoor PM 2.5 concentration and the seasonality of tuberculosis for Beijing and Hong Kong

Tuberculosis (TB) is still a serious public health problem in various countries. One of the long-elusive but critical questions about TB is what the risk factors are and how they contribute for its seasonality. An ecologic study was conducted to examine the association between the variation of outdoor PM2.5 concentration and the TB seasonality based on the monthly TB notification and PM2.5 concentration data of Hong Kong and Beijing. Both descriptive analysis and Poisson regression analysis suggested that the outdoor PM2.5 concentration could be a potential risk factor for the seasonality of TB disease. The significant relationship between the number of TB cases and PM2.5 concentration was not changed when regression models were adjusted by sunshine duration, a potential confounder. The regression analysis showed that a 10 μg/m3 increase in PM2.5 concentrations during winter is significantly associated with a 3% (i.e. 18 and 14 cases for Beijing and Hong Kong, respectively) increase in the number of TB cases notified during the coming spring or summer for both Beijing and Hong Kong. Three potential mechanisms were proposed to explain the significant relationship: (1) increased PM2.5 exposure increases host's susceptibility to TB disease by impairing or modifying the immunology of the human respiratory system; (2) increased indoor activities during high outdoor PM2.5 episodes leads to an increase in human contact and thus the risk of TB transmission; (3) the seasonal change of PM2.5 concentration is correlated with the variation of other potential risk factors of TB seasonality. Preliminary evidence from the analysis of this work favors the first mechanism about the PM2.5 exposure-induced immunity impairment. This work adds new horizons to the explanation of the TB seasonality and improves our understanding of the potential mechanisms affecting TB incidence, which benefits the prevention and control of TB disease

Variation of household electricity consumption and potential impact of outdoor PM2.5 concentration: a comparison between Singapore and Shanghai

The auto-regressive distributed lag (ARDL) bound testing approach was used to study the relationships between the monthly household electricity consumption and outdoor PM2.5 concentration with the consideration of ambient temperature and the number of rainy days for Singapore and Shanghai. It is shown that there are significant long-run relationships between the household electricity consumption and the regressors for both Singapore and Shanghai. For Singapore, a 20% increase in the PM2.5 concentration of a single month is in the long-run significantly related to a 0.8% increase in the household electricity consumption. This corresponds to an electricity overconsumption of 5.0 GWh, a total of 0.7–1.0 million USD in electricity cost, and 2.1 kilotons of CO2 emission associated with electricity generation. For Shanghai, a 20% decrease in the PM2.5 concentration of a single month is in the long-run significantly related to a 2.2% decrease in the household electricity consumption. This corresponds to a 35.0 GWh decrease in the overall household electricity consumption, 1.6–5.1 million USD decrease in electricity cost, and 17.5 kilotons of CO2 emission. The results suggest that the cost of electricity consumption should be included in the economic cost analysis of PM2.5 pollution in the future. A 1 °C increase in the monthly temperature is in the long-run significantly related to a 13.6% increase in the monthly electricity consumption for Singapore, while a 30 degree days increase in heating & cooling days (HCDD) is in the long-run significantly related to a 24.9% increase in the monthly electricity consumption for Shanghai. A 5-day increase in the number of rainy days per month is in the long-run significantly related to a 3.0% and 5.8% increase in the monthly electricity consumption for Singapore and Shanghai, respectively

Soot burnout in flames

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.Bibliography: leaves 330-335.by Koon Gee Neoh.Sc.D

Method of enhancing the stability of electroactive polymers and redox active materials

US7282261Granted Paten

Electrically conductive polymers

US6752936Granted Paten

Integration of antifouling and bactericidal moieties for optimizing the efficacy of antibacterial coatings

10.1016/j.jcis.2014.09.070Journal of Colloid and Interface Science438138-14

Bifunctional Coating with Sustained Release of 4‑Amide-piperidine-C12 for Long-Term Prevention of Bacterial Colonization on Silicone

Bacterial colonization by nosocomial pathogens on medical device surface can cause serious and life-threatening infections. We showed that 4-amide-piperidine-C12 (4AP12), the base form of 4-dodecaneamidepiperidine HCl, has broad-spectrum antimicrobial activity against both Gram-negative and Gram-positive bacteria and fungi. Resistance assay confirmed that prolonged exposure of bacteria to subinhibitory concentrations of 4AP12 did not induce resistance to 4AP12. The possible antimicrobial mechanism of 4AP12 was investigated, and attributed to the disruption of the cell membrane of microorganisms and subsequent cell lysis. The hydrophobic 4AP12 was incorporated in Pluronic F127 diacrylate (F127DA) micelles, which were then graft-copolymerized with acrylic acid and cross-linked onto ozonized silicone surface. Sulfobetaine methacrylate and F127DA were then graft-copolymerized as an antifouling layer on top of the F127DA-AA hydrogel containing the 4AP12, thus forming a microscale two-layer bifunctional coating. Sustained release of 4AP12 at a rate of up to 1 μg/day per cm² of hydrogel-coated silicone surface was achieved and this was sufficient to inhibit ∼97% of bacterial colonization by <i>Acinetobacter baumannii</i> in artificial urine medium under static condition over a 14-day period. Bacterial colonization by <i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i> under similar conditions was also significantly reduced. In addition, after 96 h exposure to flowing artificial urine (0.7 mL/min), <i>Escherichia coli</i> colonization on the 4AP12-loaded hydrogel-coated surface was reduced by ∼89% compared to the pristine surface. The concentration of 4AP12 that was released and was effective in inhibiting bacterial colonization did not result in significant cytotoxicity to human epithelial cells

Combined ATRP and ‘Click’ Chemistry for Designing Stable Tumor-Targeting Superparamagnetic Iron Oxide Nanoparticles

Important issues in the design of superparamagnetic iron oxide nanoparticles (SPIONs) for cancer diagnosis include stability under physiological conditions and specificity in targeting the cancer cells. In the present study, atom transfer radical polymerization (ATRP) was used to graft SPIONs with poly(glycidyl methacrylate-<i>co</i>-poly(ethylene glycol) methyl ether methacrylate) (SPIONs-P(GMA-<i>co</i>-PEGMA)). The PEGMA in the copolymer chain confers high stability to the nanoparticles in aqueous medium, and prevents recognition by macrophages with the aim of prolonging their <i>in vivo</i> circulation time. The GMA groups were used for conjugating the cancer targeting ligand, folic acid (FA), <i>via</i> ‘click’ chemistry. Using this method, the amount of FA conjugated to the nanoparticles (SPIONs-P(GMA-<i>co</i>-PEGMA)-FA) can be readily controlled. The specificity of cellular uptake of the nanoparticles by three different cell lines was investigated. The cellular iron uptake by KB cells (human epidermoid carcinoma) after 24 h of incubation is about thirteen and five times higher than those by 3T3 fibroblasts and macrophages, respectively. No significant cytotoxicity was observed with these three types of cells. The high targeting efficiency and biocompatibility of these nanoparticles are promising features for <i>in vivo</i> specific targeting and detection of tumor cells which overexpress the folate receptor

Photoinduced conversion of polyaniline from an insulating state to a conducting state

US7473445Granted Paten

AMPHIPHILIC COMB-SHAPED DIBLOCK POLYMER BRUSHES ON Si(100) SUBSTRATES VIA SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

Amphiphilic comb-shaped 2-hydroxyethyl methacrylate-graft-poly(styrene)-block-poly(poly (ethylene glycol) monomethacrylate) (P(HEMA)–g–PS–b–P(PEGMA)) copolymer brushes, covalently tethered on Si(100) substrate, have been successfully prepared by (i) UV-induced hydrosilylation of 4-vinylbenzyl chloride (VBC) with the hydrogen-terminated Si(100) (Si–VBC surface), (ii) surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate (HEMA) to give the Si–VBC–g–P(HEMA) surface, (iii) coupling of 2-bromoisobutyryl bromide with the HEMA units via esterification to provide the comb-shaped macroinitiators (Si–VBC–g–P(HEMA)–R3Br) for the subsequent ATRP, (iv) surface-initiated ATRP of styrene (St) to produce the Si–VBC–g–P(HEMA)–g–PS surface, and (v) the persisting of an active PS chain end can be used as the initiator for the subsequent ATRP of poly(ethylene glycol) monomethacrylate (PEGMA) to give the amphiphilic Si–VBC–g–P(HEMA)–g–PS–b–P(PEGMA) brush surface. The chemical composition and functionality of the silicon surface were tailored by the well-defined comb-shaped PS and P (PEGMA) brushes.Amphiphilic, silicon surface, ATRP, comb-shaped