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Procedures and tools for evaluation of reference x-ray powder patterns in the JCPDSICDD Powder Diffraction File are illustrated by a review of air-stable binary oxides. The reference patterns are evaluated using an available microcomputer version of the NBS*A1DS83 editorial program and PDF patterns retrieved directly from the CD-ROM in the program's input format. The patterns are compared to calculated and experimental diffractograms. The majority of the oxide patterns have been found to be in good agreement with the calculated and observed diffractograms, but are often missing some weak reflections routinely observed with a modern diffractometer. These weak reflections are added to the PDF pattern. For the remainder of the phases, patterns are redetermined.
Solid solutions are pervasive in minerals and in industrial inorganic materials. The analyst is often called upon to provide qualitative and quantitative X-ray phase analysis for specimens containing solid solutions when all that is available are Powder Diffraction File (PDF) data or commercial standards for the end members. In an earlier paper (1) we presented several examples of substantial errors in accuracy of quantitative analysis that can arise when the crystallinity and composition of the analyte standard do not match those of the analyte in the sample of interest. We recommended that to obtain more accurate quantitative analyses, one should determine the analyte composition (e.g., from XRF on grains seen in a SEM or from comparison of cell parameters with those of the end members) and synthesize an analyte standard with this composition and with a crystallinity approximating that of the analyte (e.g., as determined from peak breadth or α1/ α2 splitting).
A protocol for semi-quantitative XRD analysis of fly ash has been applied to 178 ashes in studies of the typical mineralogy of high-calcium and iow-calcium fly ash, the consistency of fly ash mineralogy from a typical power station, the partitioning of chemical constituents into crystalline phases, and the crystalline phases relevant to the use of fly ash in concrete.
Amorphous TiO2 and SnO2 electron transport layers (ETLs) were deposited by low-temperature atomic layer deposition (ALD). Surface morphology and x-ray photoelectron spectroscopy (XPS) indicate uniform and pinhole free coverage of these ALD hole blocking layers. Both mesoporous and planar perovskite solar cells were fabricated based on these thin films with aperture areas of 1.04 cm2 for TiO2 and 0.09 cm2 and 0.70 cm2 for SnO2. The resulting cell performance of 18.3 % power conversion efficiency (PCE) using planar SnO2 on 0.09 cm2 and 15.3 % PCE using mesoporous TiO2 on 1.04 cm2 active areas are discussed in conjunction with the significance of growth parameters and ETL composition.
An unexpected increase in gastroenteritis cases was reported by healthcare workers on the KwaZulu-Natal Coast, South Africa, January 2017 with >600 cases seen over a 3-week period. A case–control study was conducted to identify the source and risk factors associated with the outbreak so as to recommend control and prevention measures. Record review identified cases and controls and structured-telephonic interviews were conducted to obtain exposure history. Stool specimens were collected from 20 cases along with environmental samples and both screened for enteric pathogens. A total of 126 cases and 62 controls were included in the analysis. The odds of developing gastroenteritis were 6.0 times greater among holiday makers than residents (95% confidence interval (CI) 2.0–17.7). Swimming in the lagoon increased the odds of developing gastroenteritis by 3.3 times (95% CI 1.06–10.38). Lagoon water samples tested positive for norovirus (NoV) GI.6, GII.3 and GII.6, astrovirus and rotavirus. Eleven (55%) stool specimens were positive for NoV with eight genotyped as GI.1 (n = 2), GI.5 (n = 3), GI.6 (n = 2), and GI.7 (n = 1). A reported sewage contamination event impacting the lagoon was the likely source with person-to-person spread perpetuating the outbreak. Restriction to swimming in the lagoon was apparently ineffective at preventing the outbreak, possibly due to inadequate enforcement, communication and signage strategies.
Established methods of recruiting population controls for case–control studies to investigate gastrointestinal disease outbreaks can be time consuming, resulting in delays in identifying the source or vehicle of infection. After an initial evaluation of using online market research panel members as controls in a case–control study to investigate a Salmonella outbreak in 2013, this method was applied in four further studies in the UK between 2014 and 2016. We used data from all five studies and interviews with members of each outbreak control team and market research panel provider to review operational issues, evaluate risk of bias in this approach and consider methods to reduce confounding and bias. The investigators of each outbreak reported likely time and cost savings from using market research controls. There were systematic differences between case and control groups in some studies but no evidence that conclusions on the likely source or vehicle of infection were incorrect. Potential selection biases introduced by using this sampling frame and the low response rate are unclear. Methods that might reduce confounding and some bias should be balanced with concerns for overmatching. Further evaluation of this approach using comparisons with traditional methods and population-based exposure survey data is recommended.
The longstanding association between the major histocompatibility complex (MHC) locus and schizophrenia (SZ) risk has recently been accounted for, partially, by structural variation at the complement component 4 (C4) gene. This structural variation generates varying levels of C4 RNA expression, and genetic information from the MHC region can now be used to predict C4 RNA expression in the brain. Increased predicted C4A RNA expression is associated with the risk of SZ, and C4 is reported to influence synaptic pruning in animal models.
Based on our previous studies associating MHC SZ risk variants with poorer memory performance, we tested whether increased predicted C4A RNA expression was associated with reduced memory function in a large (n = 1238) dataset of psychosis cases and healthy participants, and with altered task-dependent cortical activation in a subset of these samples.
We observed that increased predicted C4A RNA expression predicted poorer performance on measures of memory recall (p = 0.016, corrected). Furthermore, in healthy participants, we found that increased predicted C4A RNA expression was associated with a pattern of reduced cortical activity in middle temporal cortex during a measure of visual processing (p < 0.05, corrected).
These data suggest that the effects of C4 on cognition were observable at both a cortical and behavioural level, and may represent one mechanism by which illness risk is mediated. As such, deficits in learning and memory may represent a therapeutic target for new molecular developments aimed at altering C4’s developmental role.
There is growing interest in the manipulation of dietary ingredients a means of reducing nitrogen excretion (NE) and ammonia (NH3) losses from pig production. Significant quantities of lactose may reach the hindgut of the older pig undigested, yielding a substrate for bacteria (Kim et al., 1978). It is hypothesised that increasing concentrations of lactose in finishing pig diets will alter NE patterns and reduce NH3-N emission.
The type identity of strains of Pseudomonas aeruginosa from primary and recurrent blood stream infection (BSI) has not been widely studied. Twenty-eight patients were identified retrospectively from 2008 to 2013 from five different laboratories; available epidemiological, clinical and microbiological data were obtained for each patient. Isolates were genotyped by iPLEX MassARRAY MALDI-TOF MS and rep-PCR. This showed that recurrent P. aeruginosa BSI was more commonly due to the same genotypically related strain as that from the primary episode. Relapse due to a genotypically related strain occurred earlier in time than a relapsing infection from an unrelated strain (median time: 26 vs. 91 days, respectively). Line related infections were the most common source of suspected BSI and almost half of all BSI episodes were associated with neutropenia, possibly indicating translocation of the organism from the patient's gut in this setting. Development of meropenem resistance occurred in two relapse isolates, which may suggest that prior antibiotic therapy for the primary BSI was a driver for the subsequent development of resistance in the recurrent isolate.
In Table I we present the list of 38 celestial objects that have been observed since January 1978 at 2.7 and 8.1 GHz with the Green Bank interferometer. The sources fall naturally into three categories: radio stars, possibly Galactic sources, and extragalactic sources. SS433, Cyg X-3, and each extrgalactic source is measured several times per day while the other sources are measured once every three days. Reports on the entire program will be found in Geldzahler et al. (1983a), and on specific sources: SS433—Johnston et al. (1983a), BL Lac—Johnston et al. (1983b), Cyg X-3—Geldzahler et al. (1983b) and elsewhere in this volume), and CTA 26—Spencer et al. (1983).
Cyg X-3 underwent a series of giant radio outbursts beginning on September 28, 1982 (Geldzahler et al. 1983). The flux densities at 2.7 and 8.1 GHz (11.1, 3.71 cm respectively, see Figure 1) were measured with the 2.4 km baseline of the Green Bank interferometer once every three days before October 5, 1982 (= JD 244 5248) and three times daily thereafter.
An outbreak of respiratory diphtheria occurred in two health districts in the province of KwaZulu-Natal in South Africa in 2015. A multidisciplinary outbreak response team was involved in the investigation and management of the outbreak. Fifteen cases of diphtheria were identified, with ages ranging from 4 to 41 years. Of the 12 cases that were under the age of 18 years, 9 (75%) were not fully immunized for diphtheria. The case fatality was 27%. Ninety-three household contacts, 981 school or work contacts and 595 healthcare worker contacts were identified and given prophylaxis against Corynebacterium diphtheriae infection. A targeted vaccination campaign for children aged 6–15 years was carried out at schools in the two districts. The outbreak highlighted the need to improve diphtheria vaccination coverage in the province and to investigate the feasibility of offering diphtheria vaccines to healthcare workers.
This study investigated comparatively the pathogenicity of experimental infection of mice and guinea pigs, with Angiostrongylus mackerrasae and the closely related species A. cantonensis. Time course analyses showed that A. mackerrasae causes eosinophilic meningitis in these hosts, which suggests that the species has the potential to cause meningitis in humans and domestic animals. Both A. mackerrasae and the genetically similar A. cantonensis caused eosinophilic meningitis in mice at two time points of 14 and 21 days post infection (dpi). The brain lesions in mice infected with A. mackerrasae were more granulomatous in nature and the parasites were more likely to appear degenerate compared with lesions caused by A. cantonensis. This may indicate that the mouse immune system eliminates A. mackerrasae infection more effectively. The immunologic responses of mice infected with the two Angiostrongylus species was compared by assessing ex vivo stimulated spleen derived T cells and cytokines including interferon-gamma, interleukin 4 and interleukin 17 on 14 and 21 dpi. The results were similar for mice infected with A. cantonensis and A. mackerrasae. Serum from the infected animals with either A. cantonensis or A. mackerrasae recognized total soluble antigen of A. cantonensis female worms on Western blot.
For this review we have chosen to concentrate on recent progress concerning the model atmosphere analysis of stellar winds in central stars of planetary nebulae (CSPNs). Since there is another review in these proceedings (by W.R. Hamann) devoted specifically to Wolf-Rayet type CSPNs, we will not consider them here. The reader interested in recent work on windless model atmospheres applied to CSPNs is referred to reviews by Napiwotzki (1995) and Werner et al. (1996). There is also an interesting paper by Werner (1996) on the Balmer line problem.
Most known galaxies at high redshifts have been found by concentrating on ultra steep spectrum (α≳l) sources in low frequency radio surveys (eg. Rottgering et al., 1994; McCarthy et al., 1990). We have been carrying out a systematic study of a large and complete sample from the 408 MHz Molonglo Reference Catalogue which is not biased by any spectral index criterion. Containing 558 sources, defined by S408 ≥ 0.95 Jy; −30° < δ < −20° and the RA ranges of 20h 20m to 06h00m and 09h20m to 14h00m, our sample is about 3 times larger in size and 5 times deeper in flux density than the well studied 3CRR sample.
The viewing angle of ≃45° (between the jet axis and the line of sight) dividing quasars and radio galaxies in the orientation-based unified scheme (Barthel 1989) is based largely on the observation that in the redshift range of 0.5 < z < 1.0 in the low-frequency 3CRR sample, there are about twice as many radio galaxies than quasars and the median linear size of galaxies is about twice that of the quasars. The relative numbers and sizes of quasars in other redshift ranges in the 3CRR are however in conflict with the simple unified scheme even if the opening angle is considered to evolve with epoch or radio luminosity (Kapahi 1990; Singal 1993). Larger sources samples, preferably selected at low radio frequencies, are clearly important in such statistical studies.