Development of an indoor air purification system to improve ventilation and air quality.

Novel types of an air purification system for improving indoor air quality (IAQ) and ventilation by reducing carbon dioxide (CO2) concentration were assessed in office buildings in India. This study provides an evaluation of a control system that reduces toxic gases in indoor spaces using the synthesized filter media. The reduction potential of CO2 levels of the control system, for different air handling unit (AHU) capacities, were compared. Experimental studies and in-situ evaluation has been done using the air purification system. Ventilation rates and CO2 concentration are monitored before and after the installation of the purification system. The results of the investigation indicated CO2 concentrations were reduced by more than 40% with the purification system. Fresh air intake to maintain the desired ventilation rates has been reduced to more than 50%, further reduce heat load. Ventilation flow rates were achieved with this air purification system. This system has the potential aspiration in controlling the CO2 levels in mechanically ventilated buildings. CO2 concentrations were brought down to permissible limits and maintained further without introducing fresh air into the system. Based on the results, assessment of the air purification system is a crucial and wide range of applicability in indoor environments to reduce cooling costs.

Impact of urban heat island on meteorology and air quality at microenvironments.

This study analyzes the air pollution characteristics and their relation to meteorological conditions in Chennai, India. Meteorological conditions were the primary factor determining variations in daily average pollutant concentrations. The influence of urban infrastructure on meteorology is an important prediction on air quality. Understanding of the seasonal and diurnal secondary pollutant concentrations as a function of local meteorological conditions is necessary for urban air quality management. Micro-scale models for analyzing the surface layer interactions with the surrounding environment have recently gained attention. An attempt has been made to understand the effect of meteorology on air quality. This comprehensive study aims to assess the influence of local meteorology on urban air quality. The correlation was established between the change in meteorological parameters and mixing height on air quality at selected locations in a tropical urban environment. Results indicated the significant impact of land use patterns on the dispersion of air quality at study locations. Seasonal variations of ambient air temperatures at study locations were found to be more than 3°C in summer. Average mixing height variation among the study locations was observed to be more than 200 meters in summer. Results indicated the importance of wind velocity on the mixing height at study locations. The average concentrations of air quality parameters showed significant variation among the study locations. The maximum ozone (O3) concentration was recorded at the Central Business District (CBD) during the afternoon, i.e., around 38.3 ppb, whereas it was 26.8 and 14.6 ppb at the Residential Area (RA) and Urban Baseline (UBL), respectively. A strong correlation was observed between ambient temperature and O3 concentration during summer. In the winter, the average O3 concentration in all three-study locations increased to 45.3 ppb, 45.8 ppb, and 58.5 ppb at UBL, RA, and CBD sites, respectively. The study reveals the impact of microenvironments on air quality. Implications: An attempt has been made to study the seasonal and diurnal variation of air quality levels in selected study regions with land cover change. This article focuses mainly on the surface temperature intensity variations with respect to the percentage of land use pattern change in Chennai city, India, and the subsequent effect on meteorology of dispersion conditions and air quality parameters has been studied. The relationship between local meteorology and air quality has been established.

Completion rates of anterior and posterior continuous curvilinear capsulorrhexis in pediatric cataract surgery for surgery performed by trainee surgeons with the use of a low-cost viscoelastic.

CONTEXT: Pediatric cataract surgery is traditionally done with the aid of high-molecular-weight viscoelastics which are expensive. It needs to be determined if low-cost substitutes are just as successful. AIMS: The study aims to determine the success rates for anterior and posterior capsulorrhexis and intraocular lens (IOL) implantation in the bag for pediatric cataract surgery performed with the aid of a low-molecular-weight viscoelastic. SETTINGS AND DESIGN: Nonrandomized observational study. MATERIALS AND METHODS: Children less than 6 years of age who underwent cataract surgery with IOL implantation in the period May 2008-May 2009 were included. The surgeries were done by pediatric ophthalmology fellows. A standard procedure of anterior capsulorrhexis, lens aspiration with primary posterior capsulorrhexis, anterior vitrectomy, and IOL implantation was followed. Three parameters were studied: successful completion of anterior and posterior capsulorrhexis and IOL implantation in the bag. RESULTS: 33 eyes of 28 children were studied. The success rate for completion was 66.7% and 88.2 % for anterior and posterior capsulorrhexis, respectively. IOL implantation in the bag was successful in 87.9%. CONCLUSIONS: 2% hydroxypropylmethylcellulose is a viable low-cost alternative to more expensive options similar to high-molecular-weight viscoelastics. This is of great relevance to hospitals in developing countries.

Triacontanol inhibits both enzymatic and nonenzymatic lipid peroxidation.

The effect of the plant growth regulator, triacontanol (TRIA) on lipid peroxidation was studied in three different systems: (i) isolated chloroplasts of spinach (Spinacea oleracea L.) leaves; (ii) egg lecithin liposomes; and (iii) soybean lipoxygenase (LOX) system. The nonenzymatic lipid peroxidation in isolated chloroplasts and egg lecithin liposomes was measured as the amount of thiobarbituric acid reactive substances (TBARS) formed. Inhibition of Fe2+ and/or light-induced lipid peroxidation by TRIA was observed in both isolated chloroplasts and egg lecithin liposomes. The kinetics of soybean lipoxygenase-1 (LOX-1) was studied using linoleic acid as the substrate. The enzyme was competitively inhibited by TRIA. The Ki for TRIA inhibition of the enzyme was estimated to be 3.2-5.0 microM according to different methods of estimation. TRIA has been known to exhibit anti-inflammatory action in animals and this anti-inflammatory effect of TRIA might be mediated through inhibition of lipid peroxidation. Since LOX inhibitors have been extensively used as therapeutic agents, TRIA, being a natural compound has been suggested to be an effective anti-inflammatory drug.

Microviscosity of cucumber (Cucumis sativus L.) fruit protoplast membranes is altered by triacontanol and abscisic acid.

Cucumber (Cucumis sativus L.) fruit protoplast membranes were probed with diphenylhexatriene (DPH) and pyrene, and also with two different plant growth regulators, triacontanol (TRIA) and abscisic acid (ABA). Fluorescence anisotropies of DPH and pyrene were measured after incorporating them into the membranes. The fluorescence lifetime of membrane-bound pyrene was also measured by using neodymium-doped yttrium aluminium garnet (Nd:YAG) laser of 35 ps pulses. The microviscosities of the membranes were calculated using the values of fluorescence anisotropy and lifetime. In the presence of TRIA and ABA, there was a sharp decrease in the fluorescence lifetime of pyrene. Similarly, there was also a decrease in the microviscosities of the membranes and increase in the rate of rotation of membrane-bound fluorophore, induced by the plant growth regulators. Furthermore, TRIA or TRIA + ABA could reduce the fluorescence anisotropy of both the fluorophores whereas, ABA decreased the anisotropy of only pyrene. This property of ABA may be due to its confinement to a specific spacial facet in the membrane. Fatty acid analysis indicated that membrane microviscosity fluctuations were not due to altered fatty acid composition alone as it is known that change in lipid-protein interaction would also alter the physical status of the membrane.