Characterization of Soil Shrink-Swell Potential Using the Texas VNIR Diffuse Reflectance Spectroscopy Library

Shrinking and swelling soils cause extensive infrastructure and economic damage worldwide. Shrink-swell soils are of great concern in Texas for two reasons, 1) Texas has the most acreage of shrink-swell soils in the United States, and 2) yearly evapotranspiration rates exceed those of precipitation creating optimal conditions for soil wetting and drying cycles. This study was conducted to determine if visible near infrared diffuse reflectance spectroscopy (VNIR-DRS) can be used to predict the coefficient of linear extensibility (COLE) of soils. If successful, VNIR-DRS would provide a means to rapidly and inexpensively quantify a soil’s shrink-swell potential real-time. Using soils that have been previously analyzed and archived in the Texas Agrilife Research Soil Characterization Laboratory, our objectives were to: 1) predict the coefficient of linear extractability (COLE) using spectroscopy, 2) predict COLE using measurements of total clay and cation exchange capacity (CEC), and 3) compare the two models. A total of 2454 soil samples were scanned to create the Texas spectral library. Of these samples, 1296 had COLE measurements. Seventy percent of the COLE samples were randomly selected to build a calibration model using partial least squares regression. The remaining thirty percent were used to validate the calibration model. The coefficient of determination (R2), root mean square deviation (RMSD), and relative percent difference (RPD) were calculated to assess the prediction models. The COLE prediction using spectroscopy had an R2, RMSD, and RPD of 0.61, 0.028, and 1.6, respectively. Using stepwise regression and backward elimination, we determined that CEC and total clay together were the best predictors of COLE with R2, RMSD, and RPD of 0.82, 0.019, and 2.3, respectively. According to the RPD, using spectroscopy to predict COLE has some predictive value, while using CEC and total clay is more effective and stable. However, spectroscopy data collection is more rapid and has fixed costs

Thermal outgassing of irradiated nuclear fuel: a literature review

An experimental program at PNL examined the release of volatile and semivolatile radionuclides from irradiated nuclear fuel under different modes of heat treatment. In support of this work, a literature evaluation was conducted to review the information on: physical changes in fuel and cladding; distribution, migration, and reactions of fission products; and theoretical studies. Omitted from the review are evaluations of various fission gas bubble behavior - swelling models. The different computer codes that have been used to predict fuel behavior are also not included. A large amount of work has been done on the behavior of nuclear fuels during irradiation. The goals of this work have been to ensure acceptable mechanical performance, provide safe operation, and assist in fuel design, preparation, and recycle. Many fundamental studies, including diffusion and lattice structures, are also reported. 51 references, 17 figures, 8 tables

Interaction of CO2 laser-modified nylon with osteoblast cells in relation to wettability

It has been amply demonstrated previously that CO2 lasers hold the ability to surface modify various polymers. In addition, it has been observed that these surface enhancements can augment the biomimetic nature of the laser irradiated materials. This research has employed a CO2 laser marker to produce trench and hatch topographical patterns with peak heights of around 1 μm on the surface of nylon 6,6. The patterns generated have been analysed using white light interferometery, optical microscopy and X-ray photoelectron spectroscopy was employed to determine the surface oxygen content. Contact angle measurements were used to characterize each sample in terms of wettability. Generally, it was seen that as a result of laser processing the contact angle, surface roughness and surface oxygen content increased whilst the apparent polar and total surface energies decreased. The increase in contact angle and reduction in surface energy components was found to be on account of a mixed intermediate state wetting regime owing to the change in roughness due to the induced topographical patterns. To determine the biomimetic nature of the modified and as-received control samples each one was seeded with 2×104 cells/ml normal human osteoblast cells and observed after periods of 24 hours and 4 days using optical microscopy and SEM to determine mean cell cover densities and variations in cell morphology. In addition a haeymocytometer was used to show that the cell count for the laser patterned samples had increased by up to a factor of 1.5 compared to the as-received control sample after 4 days of incubation. Significantly, it was determined that all laser-induced patterns gave rise to better cell response in comparison to the as-received control sample studied due to increased preferential cell growth on those surfaces with increased surface roughness

The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization

There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed one of two experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d post hatch. Dietary Ca content had no significant effect on in situ pH, but it contributed towards variance in ex situ pH of both gizzard and duodenum digesta

Thermal treatment of nuclear fuel-containing Magnox sludge radioactive waste

Magnesium aluminosilicate and magnesium borosilicate glass formulations were developed and evaluated for the immobilisation of the radioactive waste known as Magnox sludge. Glass compositions were synthesised using two simplified bounding waste simulants, including corroded and metallic uranium and magnesium at waste loadings of up to 50 wt.%. The glasses immobilising corroded simulant waste formed heterogeneous and fully amorphous glasses, while those immobilising metallic wastes contained crystallites of UO2 and U3O8. Uranium speciation within the glass was investigated by micro-focus X-ray absorption near edge spectroscopy and it was shown that the borosilicate glass compositions were characterised by a slightly lower mean uranium oxidation state than the aluminosilicate counterparts. This had an impact upon the durability, and uranium within glasses of higher mean oxidation states was dissolved more readily. All material showed dissolution rates that were comparable to simulant high level radioactive waste glasses, while the borosilicate-based formulations melted at a temperature suitable for modern vitrification technologies used in radioactive waste applications. These data highlights the potential for vitrification of hazardous radioactive Magnox sludge waste in borosilicate or aluminosilicate glass formulations, with the potential to achieve >95 % reduction in conditioned waste volume over the current baseline plan

Freshwater fish introductions in mediterranean-climate regions: are there commonalities in the conservation problem?

Aim To compare patterns and drivers of freshwater fish introductions across five climatically similar regions and evaluate similarities and differences in the nonnative species introduced. Location Five mediterranean-climate regions: California (USA), central Chile, south-western Australia, the Iberian peninsula (Spain and Portugal) and the south-western Cape (South Africa). Methods Species presence–absence for native and non-native fishes were collated across the regions, and patterns of faunal change were examined using univariate and multivariate statistical approaches. Taxonomic patterns in freshwater fish introductions were evaluated by comparing the number of species introduced by order to the numbers expected from binomial probabilities. Factors influencing multiple introductions of freshwater fish species in mediterranean regions were determined using generalized linear modelling. Results High levels of endemism (70–90%) were revealed for south-western Cape, south-western Australia and Chile. Despite their high rates of endemism, all regions currently have more non-native species than endemic species. Taxonomic selection was found for five orders, although this was only significant for Salmoniformes across regions. The average increase in regional compositional similarity of fish faunas resulting from non-native fish introductions was 8.0%. Important factors predicting multiple introductions of a species include previous introduction success and mean latitude of its distribution Main conclusions The mediterranean-climate regions of the world, separated by vast distances, originally had a few fish species in common but are now more similar, owing to species introductions, illustrating the extent and importance of taxonomic homogenization. Introductions are largely driven by taxonomically biased human interests in recreational fisheries, aquaculture and ornamental pet species.Centre of Excellence for Invasion Biolog

Poor compliance and increased mortality, depression and healthcare costs in patients with congenital adrenal hyperplasia

Objectives To evaluate risks of depression and all-cause mortality, healthcare utilisation costs, and treatment adherence in congenital adrenal hyperplasia (CAH) in the UK. Design and Methods A retrospective, matched-cohort study using UK primary-care data from the Clinical Practice Research Datalink linked to hospital and death-certification data. Patients diagnosed with CAH and having ≥1 corticosteroid prescription were matched 1:10 to reference subjects. Risk of death and lifetime prevalence of depression were compared using Cox regression models. Direct financial costs were estimated for healthcare contacts. Treatment adherence was measured by medical possession ratio (MPR). Results 605 patients with CAH were identified; 562 were matched. 270 CAH patients (2,700 controls) were linkable to death-certificate data, with adjusted hazard ratio for all-cause mortality 5.17 (95%CI 2.81 to 9.50). Mean (SD) age at death in CAH patients was 54.8 (23.9) versus 72.8 (18.0) years in control patients. The prevalence ratio of depression in CAH versus control patients was 1.28 (95%CI 1.13 to 1.45). Mean (SD) annual healthcare costs were higher in CAH than controls: at age 0-6 years, £7,038 (£14,846) versus £2,879 (£13,972, p<0.001); 7-17 years, £3,766 (£7,494) versus £1,232 (£2,451, p<0.001); 18-40 years, £1,539 (£872) versus £1,344 (£1,620, p=0.007); and ≥41 years, £4,204 (£4,863) versus £1,651 (£2,303, p<0.001). Treatment adherence was lowest in adults, with 141 (36%) of 396 eligible patients having an MPR <80%. Conclusions This first analysis of CAH in routine UK healthcare suggests that patients with CAH have increased mortality, depression, and healthcare utilisation, and low treatment adherence

Pre-M Phase-promoting Factor Associates with Annulate Lamellae in Xenopus Oocytes and Egg Extracts

We have used complementary biochemical and in vivo approaches to study the compartmentalization of M phase-promoting factor (MPF) in prophase Xenopus eggs and oocytes. We first examined the distribution of MPF (Cdc2/CyclinB2) and membranous organelles in high-speed extracts of Xenopus eggs made during mitotic prophase. These extracts were found to lack mitochondria, Golgi membranes, and most endoplasmic reticulum (ER) but to contain the bulk of the pre-MPF pool. This pre-MPF could be pelleted by further centrifugation along with components necessary to activate it. On activation, Cdc2/CyclinB2 moved into the soluble fraction. Electron microscopy and Western blot analysis showed that the pre-MPF pellet contained a specific ER subdomain comprising "annulate lamellae" (AL): stacked ER membranes highly enriched in nuclear pores. Colocalization of pre-MPF with AL was demonstrated by anti-CyclinB2 immunofluorescence in prophase oocytes, in which AL are positioned close to the vegetal surface. Green fluorescent protein-CyclinB2 expressed in oocytes also localized at AL. These data suggest that inactive MPF associates with nuclear envelope components just before activation. This association may explain why nuclei and centrosomes stimulate MPF activation and provide a mechanism for targeting of MPF to some of its key substrates