Search

Ultra-performance liquid chromatographic technique was applied for the first time for determination of radiochemical and chemical purity of [11C]methionine with measurement time less than 2 min. The pH and eluent strength of mobile phase were optimized to achieve a gradient elution for separation of non-radioactive impurities as well as radioactive ingredients. The developed method was validated according to the following parameters: linearity, repeatability, recovery, limit of quantitation. The novel chromatographic procedure with reduced measurement time could be uniquely applied for the quality control of [11C]methionine to considerably shorten the release time and avoid radioactivity loss of radiopharmaceutical. [ABSTRACT FROM AUTHOR]

Fish gills are constituted by primary filaments and secondary lamellae, which are formed, basically, by three different cell types: pillar cells, respiratory cells and erythrocytes that circulate in the lamellae interior. This respiratory organ is very appreciated in environmental studies since it is constantly in contact with the water, accomplishing exchanges; besides this, it presents a high adaptation capacity. In this work, some fishes were reared in polluted waters treated by the flotation method (treated group) and compared with others that were reared in clean waters (control group). The ultramorphological, histological and histochemical analyses were used. The fishes from the treated group presented morphological alterations when compared with the control groups, such as lamellar fusion, aneurism and detachment of the respiratory epithelium. These alterations demonstrate the several adaptations, as morphologic as physiologic, that fishes can present when exposed to an inappropriate environment. The techniques employed are good tools to detect morphological biomarkers in gills of Oreochromis niloticus submitted to polluted waters. [Copyright &y& Elsevier]

Abstract: Background: Viral respiratory infections play an important role in the pathogenesis of otitis media with effusion (OME) in children. The most common human rhinoviruses (HRVs) have been detected in middle ear effusions (MEE), but there is only limited data available about the closely related human enteroviruses (HEVs). The newly discovered human bocavirus (HBoV) has not, however, been identified in MEE of OME children. Objectives: The aim of our study was to determine the presence of HBoV and HRV/HEV and the rate of coinfection in a set of MEE samples collected from OME children. Study design: Seventy-five MEE samples from 54 children with no acute respiratory symptoms were studied with reverse transcription polymerase chain reaction (RT-PCR) for detection of HRV/HEV and quantitative PCR for detection of HBoV. Results: Twenty-six (35%) of 75 MEE samples were positive for viral nucleic acid, 22 (29%) for HEV, 10 (13%) for HRV and 2 (3%) for HBoV. There was no statistically significant difference between mucoid and serous effusions in the rate of virus detection. Forty-three percent of bilateral cases showed a contra-lateral difference in viral finding. Conclusions: Our results suggest that these common respiratory viruses can be associated with OME in children. Whether these viruses are causative etiologic factors of MEE persistence or merely remnants of previous infections is not known. [Copyright &y& Elsevier]

We present the first report of biotransformation of 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN), replacements for the explosives 1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT), respectively, by methane-oxidizing cultures under aerobic conditions. Two consortia, dominated by Methylosinus spp., degraded both compounds with transient production of reduced NTO products, and non-stoichiometric production of reduced DNAN products. No release of inorganic nitrogen was observed with either compound, indicating that NTO and DNAN may be utilized as nitrogen sources by these consortia. The pure culture Methylosinus trichosporium OB3b also degraded both compounds. Degradation was observed in the presence of acetylene (a known inhibitor of methane monooxygenase; MMO) when methanol was supplied, indicating that MMO was not involved. Furthermore, studies with purified soluble MMO (sMMO) from OB3b indicated that neither compound was a substrate for sMMO. Degradation was inhibited by 2-iodosobenzoic acid, but not by dicoumarol, suggesting involvement of an oxygen- and dicoumarol-insensitive (nitro)reductase. These results indicate methanotrophs can aerobically degrade NTO and DNAN via one or more (nitro)reductases, with sMMO serving a supporting role deriving reducing equivalents from methane. This finding is important because methanotrophic bacteria are widely dispersed, and may represent a previously unrecognized route of NTO and DNAN biotransformation in aerobic environments. ga1 • Methane-oxidizing bacteria biotransform NTO and DNAN. • NTO bioreduction occurred under aerobic conditions. • The direct involvement of methane monooxygenase was not observed. • Dicoumarol- and oxygen-insensitive nitroreductases are assumed to be involved. [ABSTRACT FROM AUTHOR]

Raman and infrared measurements of the same locations were conducted on a northwest African (NWA) 10580 CO3 meteorite sample, before and after three proton irradiations (1 keV ion energy using 1011, 1014, and 1017 ion/cm2 fluent values), to simulate space weathering effects. In the case of Raman spectroscopy, both FWHM and peak positions of the major olivine and pyroxene bands changed after the irradiation, and the minor bands disappeared. In the FTIR spectra, the minor bands of olivine and pyroxene also disappeared; meanwhile, major IR bands of pyroxene remained visible, demonstrating both positive and negative peak shifts, and the olivines were characterised only by negative peak shifts. The olivines were characterised by negative FWHM changes for major bands, but positive FWHM changes for minor bands. The pyroxenes were characterised by elevated FWHM changes for minor bands after the irradiation. The disappearance of minor bands both of IR and Raman spectra indicates the amorphization of minerals. The negative peak shift in IR spectra indicates Mg loss for olivine and pyroxene, in agreement with the literature. The Raman spectra are characterised by positive peak shift and positive FWHM changes; the IR spectra are characterised by a negative peak shift. The Mg loss, which was detected by negative peak shifts of FTIR bands, may be caused by distortion of the crystal structure, which could be detected by a positive peak shift in Raman spectra. This joint observation and interpretation has not been formulated in the literature, but indicates further possibilities in the confirmation of mineral changes by different instruments. Shock alteration-based observations by other researchers could be used as a reference for irradiation experiments as irradiation makes a similar structural alteration, like a low-grade shock metamorphism. [ABSTRACT FROM AUTHOR]

Effect of space weathering of airless asteroids could be better understood by artificial irradiation tests on meteorites in laboratories. This work surveys the infrared and Raman analysis based interpretation of simulated charged particle irradiation tests in order to better understand near-future observational possibilities of asteroid visiting missions and also to support the planning of next missions and directions of detector improvement. Recent works properly targeted different meteors and meteor relevant minerals, evaluating bulk meteorite spectra, during the irradiation tests. He+, (Ne+, Kr+), and Ar+ ions were used with fluxes characteristic for inner planetary system solar wind, considering 1–10 million yr exposure durations. Although main meteorite minerals were irradiated and analysed, one missing aspect is that only bulk analysis have been done, not minerals separately in their original embedded context. Some Earth based mineral references were also analysed; however, they might not necessarily behave similar to the same type of reference minerals and irradiation effect is poorly known for feldspar, troilite, and magnetite. Darkening should be also further analysed for separate minerals too, together with the record of peak shape and position changes. Infrared ATR analysis might still provide such data in the future using the recently emerged technology, as well as Raman analysis – however for flyby missions' infrared is the useful method while Raman can be used only at in situ missions. The overview including the tables to support the identification of specific missing information related gaps in our current knowledge and directions for future research. [ABSTRACT FROM AUTHOR]

The joint evaluation of different meteor observation types supports a better understanding of both meteor phenomena and the terrestrial atmosphere. Two types of examples are presented in this work, linking ionospheric effects to specific meteors, with almost one-third of the meteors that emerged at high altitudes simultaneously recorded with an optical camera. Very few such observations have been realized as yet. With daytime fireballs, the recorded infrasound effect and the atmospheric blast produced shock-wave-related small earthquakes which were identified by a network of ground stations. An overview of these observational types highlights specific topics for which substantial improvements and discoveries are expected in the near future. [ABSTRACT FROM AUTHOR]

Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation. Replicate columns were then bioaugmented with either Gordonia sp. KTR9, Pseudomonas fluorescens I-C (Ps I-C), or both strains. Under aerobic conditions (influent dissolved oxygen (DO) >6 mg/L), RDX was degraded following the addition of fructose, and to a lesser extent with lactate, in columns bioaugmented with KTR9. No degradation was observed in columns bioaugmented with only Ps I-C under aerobic conditions, consistent with the known anaerobic RDX degradation pathway for this strain. When influent DO was reduced to <2 mg/L, good RDX degradation was observed in the KTR9-bioaugmented column, and some degradation was also observed in the Ps I-C-bioaugmented column. After DO levels were kept below 1 mg/L for more than a month, columns bioaugmented with KTR9 became unresponsive to fructose addition, while RDX degradation was still observed in the Ps I-C-bioaugmented columns. These results indicate that bioaugmentation with the aerobic RDX degrader KTR9 could be effective at sites where site geology or geochemistry allow higher DO levels to be maintained. Further, inclusion of strains capable of anoxic RDX degradation such as Ps I-C may facilitate bimodal RDX removal when DO levels decrease. [ABSTRACT FROM AUTHOR]