Isolation and Characterization of Potent Strains for Metabolizing Paint VOCs from an Active Trickle‐bed Air Biofilter

In this study, seven strains of cells were isolated from a trickle‐bed air biofilter used for continuously treating paint of volatile organic compounds (VOCs) for six months. The morphology and biochemical study was conducted by streaking isolated mixed culture in solid agar slant media and the cell shapes were identified by using an electron microscope. It was found that this mixed culture was gram‐negative for seven different isolates. The isolated strains were grown on substrates including methyl ethyl ketone (MEK), toluene, n‐butyl acetate, and o‐xylene (MTBX), as the carbon and energy sources. Among the seven isolates, an AKM 02 strain had a high MTBX‐degrading activity and was identified as Shewanella putrefaciens by taxonomical analysis, biochemical tests and 16S rDNA gene analysis methods. All isolates grew in a pH range from 3.0–11.0 with an optimum range of 6.0–8.0. In addition, each of the isolates grew in the temperature range of 15–45 °C with an optimum range between 25–30 °C. The batch experiments were conducted at four different initial MTBX concentrations ranging from 100–1000 mg L^–1. S. putrefaciens was capable of completely degrading n‐butyl acetate, MEK and toluene at a concentration lower than 500 mg L^–1. When the initial concentration of n‐butyl acetate, MEK and toluene were 500 mg L^–1, S. putrefaciens could remove the n‐butyl acetate, MEK and toluene completely within 70, 98 and 110 h, respectively. However, for o‐xylene at concentration of 500 mg L^–1, incomplete degradation was observed with only 70 % of the o‐xylene degraded after 135 h. Collectively, the results indicate that the S. putrefaciens strain degrades MTBX at a faster rate, and this strain can be used effectively in trickle‐bed air biofilters for treating high strength mixtures of paint solvents.     

Growth of carbon nanotubes on carbon fibre substrates to produce hybrid/phenolic composites with improved mechanical properties

Carbon nanotubes were grown by chemical vapor deposition (CVD) on different carbon fibre substrates namely, unidirectional (UD) carbon fibre tows, bi-directional (2D) carbon fibre cloth and three dimensional (3D) carbon fibre felt. These substrates were used as the reinforcement in phenolic resin matrix to develop hybrid CF–CNT composites. The growth morphology and other characteristics of the as grown tubes were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetry (TGA) which confirmed a copious growth of multiwalled carbon nanotubes (MWNTs) on these substrates. The mechanical properties of the hybrid composites was found to increase with the increasing amount of deposited carbon nanotubes. The flexural strength (FS) improved by 20% for UD, 75% for 2D and 66% for 3D hybrid composites as compared to that prepared by neat reinforcements (without CNT growth) under identical conditions. Flexural modulus (FM) of these composites also improved by 28%, 54% and 46%, respectively.     

Structural and Optical Properties of Highly Nd-Doped Yttrium Aluminum Garnet Ceramics from Alkoxide and Glycolate Precursors

Yttrium aluminum garnet (YAG) nanopowders doped with high neodymium (Nd) content (3 at.%) were synthesized by the sol–gel processing of (i) alkoxide precursors and (ii) metal chelates formed by complexing the cations with polyethylene glycol. A stoichiometric YAG composition was obtained following both procedures; however, the agglomeration of particles was significantly higher in glycolate synthesis, which shielded residual organics from oxidation (elemental analyses). Distribution of Nd³⁺ ions in the YAG matrix, as shown by the absorption of pump energy and photoluminescence spectra of Nd:YAG ceramics, was more homogeneous in alkoxide-derived powders. The segregation of Nd centers in the glycolate-derived sample was supported by the precipitation of a crystalline Nd₂O₃ phase (X-ray diffraction) during sintering. High-resolution absorption spectra (⁴I_9/2(1)→⁴F_9/2(1)) of the powders showed that a higher absorption cross-section of glycolate-derived powders is due to Nd³⁺–Nd³⁺ ion pairing, which leads to the quenching of photoluminescence. Owing to the better dispersion of optically active centers, the photoluminescence signal was found to be substantially enhanced in alkoxide-derived Nd:YAG ceramics.     

Linkage of low-density lipoprotein size to the lipoprotein lipase gene in heterozygous lipoprotein lipase deficiency

Small low-density lipoprotein (LDL) particles are a genetically influenced coronary disease risk factor. Lipoprotein lipase (LpL) is a rate-limiting enzyme in the formation of LDL particles. The current study examined genetic linkage of LDL particle size to the LpL gene in five families with structural mutations in the LpL gene. LDL particle size was smaller among the heterozygous subjects, compared with controls. Among heterozygous subjects, 44% were classified as affected by LDL subclass phenotype B, compared with 8% of normal family members. Plasma triglyceride levels were significantly higher, and high-density lipoprotein cholesterol (HDL-C) levels were lower, in heterozygous subjects, compared with normal subjects, after age and sex adjustment. A highly significant LOD score of 6.24 at straight theta=0 was obtained for linkage of LDL particle size to the LpL gene, after adjustment of LDL particle size for within-genotype variance resulting from triglyceride and HDL-C. Failure to adjust for this variance led to only a modest positive LOD score of 1.54 at straight theta=0. Classifying small LDL particles as a qualitative trait (LDL subclass phenotype B) provided only suggestive evidence for linkage to the LpL gene (LOD=1. 65 at straight theta=0). Thus, use of the quantitative trait adjusted for within-genotype variance, resulting from physiologic covariates, was crucial for detection of significant evidence of linkage in this study. These results indicate that heterozygous LpL deficiency may be one cause of small LDL particles and may provide a potential mechanism for the increase in coronary disease seen in heterozygous LpL deficiency. This study also demonstrates a successful strategy of genotypic specific adjustment of complex traits in mapping a quantitative trait locus.     

Over 1 W fibre-coupled power from single semiconductor source forpumping of Raman fibre amplifiers and erbium-doped fibre amplifiers

For the first time, over 1W of optical power has been coupled into single-mode fibre from a single semiconductor laser diode operating at 1.45 μm. This device meets the need for a compact high power source for pumping of erbium-doped fibre amplifiers and for Raman amplification in fibres     

Loss of heterozygosity on the long arm of human chromosome 7 in sporadic renal cell carcinomas

Cytogenetic and molecular analysis of DNA sequences with highly polymorphic microsatellite markers have implicated allele loss in several chromosomal regions including 3p, 6p, 6q, 8p, 9p, 9q, 11p and 14q in the pathogenesis of sporadic renal cell carcinomas (RCCs). Deletions involving the long arm of chromosome 7 have not been described in RCCs although they have been seen in several other tumor types. However, there have been no detailed analysis of loss of heterozygosity (LOH) of 7q sequences in sporadic RCCs. We therefore studied LOH for DNA sequences on 7q with 10 highly polymorphic markers in 92 matched normal/tumor samples representing sporadic RCCs including papillary, nonpapillary, and oncocytomas in order to determine whether allelic loss could be detected in a tumor type with no visible 7q rearrangements at the cytogenetic level. We found chromosome 7q allele loss in 59 of 92 cases (64%) involving one, two, or more microsatellite markers. The most common allele loss included loci D7S522 (24%) and D7S649 (30%) at 7q31.1-31.2, a region that contains one of the common fragile sites, FRA7G. By comparative multiplex PCR analysis, we detected a homozygous deletion of one marker in the 7q 31.1-31.2 region in one tumor, RC21. These results support the idea that a tumor suppressor gene in 7q31 is involved in the pathogenesis of sporadic renal cell carcinomas.     

Inhibitory effect of calcitonin gene-related peptide on myometrial contractility is diminished at parturition

The uterus is innervated by calcitonin gene-related peptide (CGRP) immunoreactive neurons, and CGRP inhibits spontaneous and evoked contractions in the uterus and fallopian tubes. In the present study using isometric force measurements on myometrial strips, we determined that CGRP inhibition of acetylcholine-induced contractions was drastically reduced at parturition compared with earlier stages of pregnancy in mice. The levels of inhibition exerted by CGRP paralleled the expression of a novel protein recently implicated in CGRP receptor activation, the CGRP-receptor component protein (CGRP-RCP). The mouse CGRP-RCP complementary DNA was isolated from uterus, and expression of the CGRP-RCP was monitored during gestation by Northern and Western blot analysis. Although CGRP-RCP messenger RNA levels did not vary significantly during gestation and postpartum, CGRP-RCP protein was greatly diminished at parturition. This diminution correlated with the loss of CGRP inhibition of acetylcholine-induced contractions observed in the force experiments. A role for CGRP and CGRP-RCP in modulation of myometrial smooth muscle contractility during pregnancy and in labor is suggested.     

Efficacy and safety of prophylactic cranial irradiation in patients with small cell lung cancer

In this review we examine the complex interactions between lipoprotein metabolism, immunosuppressive drug therapy, and inflammation and the potential benefits of lipid-lowering drug therapy after heart transplantation. The newer formulations of cyclosporine, Neoral (Novartis Pharmaceuticals; Basle, Switzerland), and other newer agents such as tacrolimus may have advantages in regard to lipid metabolism as compared with traditional triple-drug immunosuppression. Lipoprotein levels may influence both the toxicity and efficacy of cyclosporine. Dyslipidemia may adversely influence inflammation and rejection in the allograft. Two recent clinical trials have shown that lipid-lowering therapy with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor alone or in combination with low-density lipoprotein apheresis may confer significant benefits toward preventing transplant coronary artery disease.     

Radioadaptive response in lymphocytes of children living in territories polluted by radionuclides as a result of the accident at the Chernobyl power plant

The radioadaptive response and antimutagenic action of lymphoblastoid interferon in the human blood lymphocytes of the children from polluted after Chernobyl accident Bryansk region were studied. Cells pretreated with tritiated thymidine with 2 Gy of gamma-rays at 20 h of culture after PHA-stimulation on seven of the ten donors result in lack of radioadaptive response. On testing some of them (4 donors) no protective adaptive response was found, others (3 donors) pretreated with tritiated thymidine gave sensibilization. Significant decrease in interferon antimutagenic activity in lymphocytes with disturbed adaptive response was also found. It has been proposed that there is similarity or identity of mechanism of radioadaptive response and of non-repair component of interferons antimutagenic action.     

Targeted deletion of alkylpurine-DNA-N-glycosylase in mice eliminates repair of 1,N6-ethenoadenine and hypoxanthine but not of 3,N4-ethenocytosine or 8-oxoguanine

It has previously been reported that 1,N6-ethenoadenine (epsilonA), deaminated adenine (hypoxanthine, Hx), and 7,8-dihydro-8-oxoguanine (8-oxoG), but not 3,N4-ethenocytosine (epsilonC), are released from DNA in vitro by the DNA repair enzyme alkylpurine-DNA-N-glycosylase (APNG). To assess the potential contribution of APNG to the repair of each of these mutagenic lesions in vivo, we have used cell-free extracts of tissues from APNG-null mutant mice and wild-type controls. The ability of these extracts to cleave defined oligomers containing a single modified base was determined. The results showed that both testes and liver cells of these knockout mice completely lacked activity toward oligonucleotides containing epsilonA and Hx, but retained wild-type levels of activity for epsilonC and 8-oxoG. These findings indicate that (i) the previously identified epsilonA-DNA glycosylase and Hx-DNA glycosylase activities are functions of APNG; (ii) the two structurally closely related mutagenic adducts epsilonA and epsilonC are repaired by separate gene products; and (iii) APNG does not contribute detectably to the repair of 8-oxoG.