Synthesis and Structure of Hg1?xCrxSr2CuO4+δ Mercurocuprates

We report preliminary results concerning the synthesis and structural characterisation of the chromium stabilised 1201 phases: Hg_1–xCr_xSr₂CuO₄₊. A systematic study of the formation of phases in this system has been undertaken, together with a combined powder neutron and synchrotron x-ray diffraction study, to address the issue of chromium clustering and ordering in this system.     

Stieglitz,Martin Buber,and the equivalent

Abstract

Photographic images are capable of providing both creator and viewer with a highly aesthetic, intellectually stimulating, emotionally charged, ineffable experience. However, that potential may be very limited. The quality of the relationship starts with the intent and attention of photographer and viewer respectively, where both must be able to draw on similar referents, similar emotional responses, and similar aesthetic assumptions about interpretation. To the degree that parties in the communication process share similar intentions in understanding images, I submit that images can be transcendental equivalents.     

Effects of sintering temperature on the internal barrier layer capacitor (IBLC) structure in CaCu3Ti4O12 (CCTO) ceramics

The formation of the internal barrier layer capacitor (IBLC) structure in CaCu₃Ti₄O₁₂ (CCTO) ceramics was found to be facilitated by the ceramic heat treatment. Electrically insulating grain boundary (GB) and semi-conducting grain interior areas were characterized by impedance spectroscopy to monitor the evolution of the IBLC structure with increasing sintering temperature T_S (975–1100 °C). The intrinsic bulk and GB permittivity increased by factors of ≈2 and 300, respectively and the bulk resistivity decreased by a factor of ≈10³. These trends were accompanied by increased Cu segregation from the CCTO ceramics as detected by scanning electron microscopy and quantitative energy dispersive analysis of X-rays. The chemical changes due to possible Cu-loss in CCTO ceramics with increasing T_S are small and beyond the detection limits of X-ray absorption spectroscopy near Cu and Ti K-edges and Raman Spectroscopy.     

Agricultural intensification, priming for persistence and the emergence of Nipah virus: a lethal bat-borne zoonosis

Emerging zoonoses threaten global health, yet the processes by which they emerge are complex and poorly understood. Nipah virus (NiV) is an important threat owing to its broad host and geographical range, high case fatality, potential for human-to-human transmission and lack of effective prevention or therapies. Here, we investigate the origin of the first identified outbreak of NiV encephalitis in Malaysia and Singapore. We analyse data on livestock production from the index site (a commercial pig farm in Malaysia) prior to and during the outbreak, on Malaysian agricultural production, and from surveys of NiV''s wildlife reservoir (flying foxes). Our analyses suggest that repeated introduction of NiV from wildlife changed infection dynamics in pigs. Initial viral introduction produced an explosive epizootic that drove itself to extinction but primed the population for enzootic persistence upon reintroduction of the virus. The resultant within-farm persistence permitted regional spread and increased the number of human infections. This study refutes an earlier hypothesis that anomalous El Niño Southern Oscillation-related climatic conditions drove emergence and suggests that priming for persistence drove the emergence of a novel zoonotic pathogen. Thus, we provide empirical evidence for a causative mechanism previously proposed as a precursor to widespread infection with H5N1 avian influenza and other emerging pathogens.     

The effect of heat input on the microstructure and properties of nickel aluminum bronze laser clad with a consumable of composition Cu-9.0Al-4.6Ni-3.9Fe-1.2Mn

The effect of heat input in the laser cladding of nickel aluminum bronze was investigated. Nickel aluminum bronze castings were clad with a consumable of the composition Cu-9.0Al-4.6Ni-3.9Fe-1.2Mn and exposed to a variety of heat inputs from 42.5 to 595 J/mm. At the lowest heat input, the deposit microstructure was almost entirely martensitic. Increases in heat input caused the amount of α to increase. Depending upon heat input, the α was present as grain boundary allotriomorphs, secondary Widmanstätten α sideplates, and intragranular Widmanstätten α precipitates. The reheated zones were of lower hardness and, at all heat inputs, consisted of a mixture of grain boundary allotriomorphs and Widmanstätten α and martensite. Laser cladding improved the corrosion- and cavitation-erosion resistance of the surfaces but reduced their ductility. The properties of the clad surfaces depended on heat input.     

Charged device model metrology: limitations and problems

The inconsistent readings of various charged device model (CDM) test heads indicates severe metrology problems exist. Test head-to-test head response times vary by factors of two to three and no independent calibration method exists. CDM waveforms depend upon the total measurement system. This paper discusses the problems and methods necessary to the accurate capture of CDM waveforms.     

The structure of ion beam amorphised zirconolite studied by grazing angle X-ray absorption spectroscopy

Ti K edge X-ray absorption spectroscopy (XAS) was applied to determine the Ti co-ordination environment in the surface amorphised layer formed on zirconolite ceramics by 2 MeV Kr⁺ irradiation, to a fluence of 5 × 10¹⁵ ions cm^?2. The application of XAS in a grazing angle geometry was demonstrated to be essential in order to probe only the surface damaged layer (<1000 nm thick), in isolation of the undamaged interior of the specimen. 2 MeV Kr⁺ irradiation induced a change in the Ti co-ordination environment from majority six fold to majority five fold in the amorphised surface layer. This finding is consistent with the formation of five fold Ti in metamict natural zirconolite, as reported previously and confirmed in this study, despite the difference in dose rate of at least 10¹² between ion beam irradiated and naturally metamict materials. This study therefore opens the door to systematic investigation of composition – structure – property relations in materials designed for radioactive waste immobilisation, through the combined application of ion beam irradiation and grazing angle XAS.     

On the existence of the compound “Ce_3NbO_(7+δ)” prepared under air atmosphere

The solid state synthesis of the phase "Ce_3 NbO_(7+δ)",from stoichiometric quantities of CeO_2 and Nb_2 O_5,was investigated under air atmosphere,as previously described by Zhang et al.(Journal of Rare Earths,2007,25,730-733),A combination of powder X-ray diffraction,scanning electron microscopy with energy dispersive X-ray analysis,and laboratory Ce L_3 X-ray absorption spectroscopy,demonstrates the product of the reaction to be a mixture of CeO_2 and CeNbO_4.These data,and reexamination of the published X-ray diffraction data of "Ce_3 NbO_(7+δ)",are consistent with this phase in fact being CeO_2.No evidence for the formation of a phase of composition "Ce_3 NbO_(7+δ)" is found,by solid state synthesis under air atmosphere.     

Sensitive detection of sample interference in environmental qPCR

Sample interference in environmental applications of quantitative PCR (qPCR) can prevent accurate estimations of molecular markers in the environment. We developed a spike-and-recovery approach using a mutant strain of Escherichia coli that contains a chromosomal insertion of a mutant GFP gene. The method was tested in water samples by separately reducing extraction efficiency or adding humic acids and ethanol, compounds that often contaminate environmental DNA extracts, and analyzing qPCR amplification of the spiked E. coli control and human fecal Bacteroides markers (HF183 and HF134). This approach, coupled with previously developed kinetic outlier detection (KOD) methods, allowed sensitive detection of PCR inhibition at much lower inhibitor concentrations than alternative approaches using Cq values or amplification efficiencies. Although HF183 was more sensitive to the effects of qPCR inhibitors than the E. coli control assay, KOD methods correctly identified inhibition of both control and HF183 assays in samples containing as little as 0.1 ng humic acids per reaction or 5% ethanol. Because sigmoidal modeling methods allow distinction of qPCR inhibition from poor DNA recovery, we were able to simultaneously identify qPCR-inhibited reactions and estimate recovery of nucleic acids in environmental samples using a single control assay. Since qPCR is currently used to estimate important water quality parameters that have serious economic and human health outcomes, these results are timely. While we demonstrate the methods in the context of water quality regulation, they will be useful in all areas of environmental research that use qPCR.     

Prevalence and antibiotic susceptibility of Salmonella isolated from beef animal hides and carcasses

This study determined the prevalence of Salmonella on beef animal hides and carcasses and antimicrobial susceptibility profiles against a panel of 13 antibiotics. In each of the eight commercial packing facilities, of which five processed primarily heifers and steers and the remaining three processed primarily cows and bulls, hide and carcass sponge swab samples were obtained immediately before hide removal and before carcass chilling, respectively. Overall, prevalence of Salmonella on external surfaces (hides) of cattle was 15.4% (49 of 319), whereas prevalence after dehiding and other slaughtering/dressing processes, including the application of decontamination treatments, was, as expected, reduced (P < 0.05) to 1.3% (4 of 320) on carcass surfaces. From 53 total Salmonella-positive hide and carcass samples, 526 biochemically confirmed isolates were obtained to determine antimicrobial susceptibility profiles. Of 53 Salmonella-positive samples, individually, 24 (45.3%), 17 (32.1%), 17 (32.1%), 11 (20.8%), 8 (15.1%), 8 (15.1%), 8 (15.1%), 4 (7.5%), and 2 (3.8%) samples yielded at least one isolate resistant to amoxicillin/clavulanic acid, tetracycline, streptomycin, sulfonamides, ampicillin, ampicillin/sulbactam, chloramphenicol, gentamicin, and trimethoprim/sulfamethoxazole, respectively. None of the Salmonella-positive samples yielded an isolate resistant to ceftriaxone, ciprofloxacin, enrofloxacin, or levofloxacin. Although none of the samples yielded an isolate simultaneously resistant to three or four antimicrobials, a total of eight samples yielded at least one isolate resistant to five or more antimicrobials tested. Included among the 18 group B-positive samples were three samples that, individually, yielded at least one Salmonella Typhimurium var. Copenhagen DT104 isolate resistant to at least six antimicrobials tested. Results from this study support current prudent therapeutic and subtherapeutic antimicrobial use recommendations.