Indoor air pollution and its impact on children under five years old in Bangladesh

Indoor air concentrations of volatile organic compounds (VOCs), carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), and dust particles were measured for 49 biomass and 46 fossil fuel users in urban slums of Dhaka, Bangladesh. The health impacts of these pollutants were assessed on 65 and 51 children under five years old from families who use biomass and fossil fuel as main source of energy, respectively. Mean concentrations of CO were found to be significantly higher in biomass fuel users (P = 0.010), while geometric mean concentrations of benzene, xylene, toluene, hexane, total VOCs, and NO2 were significantly higher (P < 0.01) in the fossil fuel users. Symptoms such as redness of eyes, itching of skin, nasal discharge, cough, shortness of breath, chest tightness, wheezing, or whistling chest were found to be associated with the choice of biomass fuel, with the odds ratio ranging from 4.0 to 6.3. No significant association of use of biomass fuel with respiratory diseases, eczema, diarrhea, or viral fever was observed after adjustment for potential confounders. These results suggest a significant association between the biomass fuel-using population and respiratory symptoms. These symptoms may not be due to the pollutants only, as some other underlying causes may be present. PRACTICAL IMPLICATIONS: The health of children under five years old in Bangladesh, especially those living in poor socioeconomic conditions, is considered to be worsening because of indoor air pollution. It is commonly suggested that biomass fuel should be replaced by fossil fuel, as pollution levels are believed to be higher with biomass fuel. Our findings, however, suggest that pollution can be higher with fossil fuels, and indicate that a switch in fuel from biomass to fossil does not necessarily improve the children's health. Awareness programs should therefore be undertaken to avoid the unnecessary use of gas. Clean fuels and clean stoves should also be ensured to reduce emissions of indoor air pollutants.     

Effects of low- or medium-pressure ultraviolet lamp irradiation on Microcystis aeruginosa and Anabaena variabilis

A pure culture of Microcystis aeruginosa or Anabaena variabilis, the representatives of water blooming algae, was exposed to low-pressure (LP) or medium-pressure (MP) UV lamps. Irradiated pure culture suspension was subsequently incubated for 7d under white light fluorescent lamps. During incubation, profiles of the number of cells, DNA damage and photosynthetic activity were determined. When UV fluence was 600mJ/cm(2), M. aeruginosa cell numbers decreased throughout the 7-d incubation period, to produce 1.5log reduction (LP) or 1.2log reduction (MP) compared with control. The amount of DNA damage was 2.02x10(-4) ESS/base (LP) and 3.42x10(-4) ESS/base (MP) just after UV irradiation, which became 0.05x10(-4) ESS/base and 0.23x10(-4) ESS/base, respectively, after 3d incubation. However, cell number kept decreasing, even after DNA repair. Photosynthetic activity decreased by 1.5log within 1d (LP) or 3d (MP). Thus, reduction in photosynthetic activity could contribute to the reduction in M. aeruginosa cell numbers. A. variabilis cell numbers reduced by 2.3log (LP) or 2.2log (MP) during the 7-d incubation period; however, after DNA damage repair, cell number began to increase. The amount of DNA damage was 6.07x10(-4) ESS/base (LP) and 4.48x10(-4) ESS/base (MP) just after UV irradiation, which became 0.23x10(-4) ESS/base and 0.40x10(-4) ESS/base, respectively, after 3d incubation. No reduction was observed in photosynthetic activity/cell. Therefore, DNA damage is the main contributor of the reduction in cell number of A. variabilis.     

Two acyl-CoA dehydrogenases of Acinetobacter sp. strain M-1 that uses very long-chain n-alkanes

Two genes encoding acyl-CoA dehydrogenases, acdA and acdB, arranged in tandem, were found in the chromosomal DNA of Acinetobacter sp. strain M-1. AcdA was purified from the parental strain and AcdB was purified from an Escherichia coli strain expressing the cloned gene. The substrate specificities of the two enzymes suggest that AcdA is a medium-chain acyl-CoA dehydrogenase and that AcdB is a long-chain acyl-CoA dehydrogenase. Characterization of n-alkane metabolism in Acinetobacter sp. strain M-1 has revealed parallel pathways as well as enzymes with overlapping specificities in a single pathway. The two acyl-CoA dehydrogenases described here provide another example of the physiological complexity underlying n-alkane utilization.     

涤棉针织物分散/活性一浴一步法染色工艺

通过试验，优选出适合弱碱性与中性条件下一浴一步法染涤棉混纺针织物的染料和染色工艺。ERD系列分散染料较适合一浴法碱性浴染色，使用β-环糊精有增深作用，且匀染效果明显。部分B型染料在中性条件下比在弱碱性条件下的K／S值高。     

Rapid erasing of wettability patterns based on TiO2-PDMS composite films

TiO₂-polydimethylsiloxane (TiO₂-PDMS) composite films are prepared using the sol–gel method from a Ti(OBu)₄–benzoylacetone solution containing PDMS. The prepared films are cured by irradiation with ultraviolet (UV) light. Structural changes in the films after UV irradiation are confirmed by UV–vis absorption experiments, which show that an absorption band characteristic of the benzoylacetonate chelate rings disappears. This finding is ascribed to structural changes associated with the dissociation of the chelate rings. The IR spectra of the thin films exhibit a broad absorption band after UV irradiation, indicating that a Ti–O–Ti network forms in the thin film. Contact angles are measured for the TiO₂-PDMS thin films, showing wettability conversion from hydrophobic to superhydrophilic states by irradiation with oxygen plasma for 1 s. This phenomenon is explained by XPS experiments which reveal that the number of carbon atoms decreases, whereas the number of oxygen atoms increases on the surface of the TiO₂-PDMS composite films. Finally, hydrophobic–superhydrophilic patterns are fabricated based on a patterned TiO₂-PDMS composite film. The film displays a rapid change to superhydrophilicity over the whole film surface upon plasma irradiation for 1 s, which means that the wettability patterns are rapidly erasable.     

Intermolecular Interaction of [60]Fullerene with Tröger's Base Analogues

Tröger's base (TB, 1) and its analogues were synthesized and were subject to the titration experiments to evaluate their ability of supramolecular complexation with C₆₀. Results demonstrate clearly that the fluorene-based TB analogue (2) and the bioctylfluorene-based TB analogue (3) show 1:1 binding with C₆₀ to form the corresponding complexes while TB 1 does not. Titration experiments exhibited that the association constant (K_ass) of 3/C₆₀ (48.1 ± 7.9 M ^?1) was larger than that of 2/C₆₀ (13.7 ± 1.4 M ^?1)_. The formation of the 1:1 binding complexes 2/C₆₀ and 3/C₆₀ was also confirmed by MALDI-TOF mass spectrometry. Theoretical calculations suggest that 2 and 3 have appropriate cavities to embrace C₆₀. These findings indicate that not only the π/π interaction between the fluorene moieties and the C₆₀ surface but also the CH/π interaction between the octyl groups and the C₆₀ surface serve efficiently in the supramolecular complexation with C₆₀.     

Effects of azelastine on the level of serum interleukin-4 and soluble CD23 antigen in the treatment of nasal allergy

Research findings and various published studies point to interleukin 4 (IL-4) and CD23 antigen as instrumental in allergic reactions of allergy patients because these two substances are part of the main triggering mechanisms in cells producing IgE antibodies. In this study it was investigated whether the control of IL-4 and CD23 levels result in a decrease of the severity of allergic reactions. It is well known that azelastine hydrochloride (AZ, CAS 79307-93-0) suppresses symptoms of nasal allergy. The antiallergic activity of this drug includes the suppression of IgE antibody production, antigen-antibody reactions, liberation of mediators and mediator antagonism. One report states that the cytokines IL-2, IL-3, and IL-4 were suppressed by AZ in cultured cells. There have been no reports regarding cytokines in clinical treatment using AZ. Therefore, the effects of AZ treatment on IL-4, soluble CD23, and RAST (radioallergosorbent test) levels in the sera of allergic rhinitis patients were studied. The results show that the levels of IL-4 and soluble CD23 were significantly reduced by the administration of AZ over a 4-week period, especially in patients with "excellent" or "good" efficacy of therapy.     

Temperature dependence of cyclic creep behavior of a Cu–SiO2 bicrystal with a [0 1 1] 20° twist boundary

Temperature dependence of cyclic creep behavior has been studied using a Cu bicrystal containing dispersed SiO₂ particles and a [0 1 1] 20° twist boundary. Failure occurred at shorter times with increasing temperature and stress amplitude. The fracture-mode of the bicrystals changed sharply from transgranular to intergranular at a certain critical stress amplitude. The brittle intergranular fracture that occurred below the critical stress amplitude caused discontinuous life shortening. The observed fracture-mode change at the critical stress amplitude is discussed in relation to grain-boundary sliding and grain-boundary cracking.