Modes of occurrence and geochemistry at DSDP Holes 69-505A and 69-505B

The compositions of chrome spinels of Costa Rica Rift basalts from Deep Sea Drilling Project Site 505 vary depending on their occurrences as (1) inclusions in olivine crystals, (2) inclusions in Plagioclase crystals, and (3) isolated crystals in variolitic or glassy samples. The variations are a consequence of (1) changes of melt compositions as crystallization proceeds, and (2) contrasting behavior of olivine and Plagioclase in competition with spinels for Al and Mg. Some spinels have skeletal rims compositionally less magnesian than mineral cores; however, the cores do not appear to be xenocrysts, unlike some texturally similar spinels in Mid-Atlantic Ridge basalts.

Fibroblast growth factor 23 and markers of mineral metabolism in individuals with preserved renal function

Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that regulates phosphate homeostasis. Circulating FGF23 is elevated in chronic kidney disease (CKD) and independently associated with poor renal and cardiovascular outcomes and mortality. Because the study of FGF23 in individuals with normal renal function has received little attention, we examined in a large, population based study of 1128 participants the associations of FGF23 with markers of mineral metabolism and renal function. The median estimated glomerular filtration rate (eGFR) of the cohort was 105 ml/min per 1.73 m2, and the median plasma FGF23 was 78.5 RU/ml. FGF23 increased and plasma 1,25-dihydroxyvitamin D3 decreased significantly below an eGFR threshold of 102 and 99 ml/min per 1.73 m2, respectively. In contrast, plasma parathyroid hormone increased continuously with decreasing eGFR and was first significantly elevated at an eGFR of 126 ml/min per 1.73 m2. On multivariable analysis adjusting for sex, age, body mass index, and GFR, FGF23 was negatively associated with 1,25-dihydroxyvitamin D3, and urinary absolute and fractional calcium excretion but not with serum calcium or parathyroid hormone. We found a positive association of FGF23 with plasma phosphate, but no association with urinary absolute or fractional phosphate excretion and, unexpectedly, a positive association with tubular maximum phosphate reabsorption/GFR. Thus, in the absence of CKD, parathyroid hormone increases earlier than FGF23 when the eGFR decreases. The increase in FGF23 occurs at a higher eGFR threshold than previously reported and is closely associated with a decrease in 1,25-dihydroxyvitamin D3. We speculate that the main demonstrable effect of FGF23 in the setting of preserved renal function is suppression of 1,25-dihydroxyvitamin D3 rather than stimulation of renal phosphate excretion.

Characterizing Healthcare Utilization, Direct Costs, and Comorbidities Associated with Interstitial Cystitis: A Retrospective Claims Analysis

Thesis (Master's)--University of Washington, 2016-06

Characterization of Organophosphate Pesticides in Urine and Home Environment Dust in an Agricultural Community

Thesis (Master's)--University of Washington, 2016-06

Urinary porphyrins as biomarkers for arsenic exposure among susceptible populations in Guizhou Province, China

Coal is widely used in PR China. Unfortunately, coal from some areas in Guizhou Province contains elevated levels of arsenic. This has caused arsenicosis in individuals who use arsenic-contaminated coal for the purposes of heating, cooking and drying of food in poorly ventilated dwellings. The population at risk has been estimated to be approximately 200,000 people. Clinical symptoms of arsenicosis may include changes of skin pigmentation, hyperkeratosis of hand and feet, skin cancers, liver damage, persistent cough and chronic bronchitis. We analyzed the porphyrin excretion profile using a HPLC method in urine samples collected from 113 villagers who lived in Xing Ren district, a coal-bome arsenicosis endemic area and from 30 villagers from Xing Yi where arsenicosis is not prevalent. Urinary porphyrins were higher in the arsenic exposed group than those in the control group. The correlation between urinary arsenic and porphyrin concentrations demonstrated the effect of arsenic on heme biosynthesis resulting in increased porphyrin excretion. Both uroporphyrin and coproporphyrin III showed significant increases in the excretion profile of the younger age (< 20 years) arsenic-exposed group, suggesting that porphyrins could be used as early warning biomarkers of chronic arsenic exposure in humans. Greater increases of urinary arsenic and porphyrins in women, children and older age groups who spend much of their time indoors suggest that they might be at a higher risk. Whether elevated porphyrins could predict adverse health effects associated with both cancer and non-cancer end-points in chronically arsenic-exposed populations need further investigation. (c) 2005 Elsevier Inc. All rights reserved.

Analysis of plant microfossils in archaeological deposits from two remote archipelagos: The Marshall Islands, Eastern Micronesia, and the Pitcairn Group, Southeast Polynesia

Pollen and starch residue analyses were conducted on 24 sediment samples from archaeological sites on Maloelap and Ebon Atolls in the Marshall Islands, eastern Micronesia, and Henderson and Pitcairn Islands in the Pitcairn Group, Southeast Polynesia. The sampled islands, two of which are mystery islands (Henderson and Pitcairn), previously occupied and abandoned before European contact, comprise three types of Pacific islands: low coral atolls, raised atolls, and volcanic islands. Pollen, starch grains, calcium oxylate crystals, and xylem cells of introduced non-Colocasia Araceae (aroids) were identified in the Marshalls and Henderson (ca. 1,900 yr B.P. and 1,200 yr B.P. at the earliest, respectively). The data provide direct evidence of prehistoric horticulture in those islands and initial fossil pollen sequences from Pitcairn Island. Combined with previous studies, the data also indicate a horticultural system on Henderson comprising both field and tree crops, with seven different cultigens, including at least two species of the Araceae. Starch grains and xylem cells of Ipomoea sp., possibly introduced 1. batatas, were identified in Pitcairn Island deposits dated to the last few centuries before European contact in 1790.

The relationships between microstructure and crystal structure in zincite solid solutions

Single phase (Zn,Fe)(1-x) O zincite solid solution samples have been prepared by high temperature equilibration in air and in reducing atmospheres, followed by quenching to room temperature. The Fe2+/Fe3+ concentrations in the samples have been determined using wet chemical and XPS techniques. Iron is found to be present in zincite predominantly in the form of Fe3+ ions. The transition from an equiaxed grain morphology to plate-like zincite crystals is shown to be associated with increasing Fe3+ concentration, increasing elongation in < 001 > of the hexagonal crystals and increasing anisotropic strain along the c-axis. The plate-like crystals are shown to contain planar defects and zincite polytypes at high iron concentrations.

The growth, structure and properties of sputtered barium titanate thin films

The design and construction of a sputtering system for the deposition of barium titanate thin films is described. The growth and structure of barium titanate films deposited on a variety of substrates including amorphous carbon fi1ms, potassium bromide single crystals, and polycrystalline gold films has been studied. Films deposited on all substrates at room temperature were amorphous. Polycrystalline titanate films were formed on polycrystalline and amorphous substrates at temperatures above 450°C while films with a pronounced texture could be expitaxially deposited on single crystal potassium bromide above a temperature of only 200°C. Results of dielectric measurements made on the films are reported. Amorphous films were highly insulating (resistivities ~1014 ohm.cm with dielectric constants of between 10 and 20.

Tetrahydrobiopterin metabolism in depression and senile dementia of Alzheimer type

Excretion of biopterin and the related pteridines neopterin and pterin was measured in urine samples from a group of 76 male and female unipolar and bipolar depressed outpatients receiving lithium therapy, and compared to 61 male and female control subjects. The ratio of neopterin to biopterin excreted (N/B) was significantly higher in the patients than the controls. The significant positive correlation between urinary neopterin and biopterin shown by the controls was absent in the patients, indicating disrupted biosynthesis of tetrahydrobiopterin.Urinary cortisol excretion in depressed patients was similar to controls, implying normal hypothalmus-pituitary-adrenal axis function in these patients, Serum folate was shown to correlate with urinary total biopterin excretion in female unipolar patients. Two groups of elderly females with senile dementia of Alzheimer type (SDAT) were examined for urinary pteridine excretion. In the first study of 10 patients, the N/B ratio was significantly higher than in 24 controls and the ratio B/B+ N significantly lower. A second study of 30 SDAT patients and 21 controls confirmed these findings. However, neopterin correlated with biopterin in both patients and controls, indicating that the alteration in tetrahydrobiopterin metabolism may be different to that shown in depression. Lithium had no effect in vivo or in vitro on Wistar rat brain or liver biosynthesis of tetrahydrobiopterin at a range of concentrations and duration of dosing period, showing that lithium was not responsible for the lowered biopterin excretion by depressed patients. No significant effects on tetrahydrobiopterin metabolism in the rat were shown by the tricyclic antidepressant imipramine, the anticonvulsant sodium valproate, the vitamin folic acid, the anticatecholaminergic agent amethylparatyrosine, the synthetic corticosteroid dexamethasone, or stimulation of natural cortisol by immobilisation stress. Scopolamine, an ant ichol inergic drug, lowered rat brain pterin which may relate to the tetrahydrobiopterin deficits shown in SDAT.

Structure and dynamics of thin colloidal films

This thesis begins by studying the thickness of evaporative spin coated colloidal crystals and demonstrates the variation of the thickness as a function of suspension concentration and spin rate. Particularly, the films are thicker with higher suspension concentration and lower spin rate. This study also provides evidence for the reproducibility of spin coating in terms of the thickness of the resulting colloidal films. These colloidal films, as well as the ones obtained from various other methods such as convective assembly and dip coating, usually possess a crystalline structure. Due to the lack of a comprehensive method for characterization of order in colloidal structures, a procedure is developed for such a characterization in terms of local and longer range translational and orientational order. Translational measures turn out to be adequate for characterizing small deviations from perfect order, while orientational measures are more informative for polycrystalline and highly disordered crystals. Finally, to obtain an understanding of the relationship between dynamics and structure, the dynamics of colloids in a quasi-2D suspension as a function of packing fraction is studied. The tools that are used are mean square displacement (MSD) and the self part of the van Hove function. The slow down of dynamics is observed as the packing fraction increases, accompanied with the emergence of 6-fold symmetry within the system. The dynamics turns out to be non-Gaussian at early times and Gaussian at later times for packing fractions below 0.6. Above this packing fraction, the dynamics is non-Gaussian at all times. Also the diffusion coefficient is calculated from MSD and the van Hove function. It goes down as the packing fraction is increased.

Chemical composition of hydrothermal carbonates and barites from the Deryugin Basin, Sea of Okhotsk

Data on hydrothermal activity in the Deryugin Basin (Sea of Okhotsk) are reviewed. Barites and carbonates found in sediment cores sampled at feet of hydrothermal mounds were subdivided into recycled and authigenic types. Recycled minerals were represented by crystals and aggregations of travertine-like barite and fragments of barite and carbonate tubes. Authigenic formations included: (1) carbonate nodules; (2) barite micronodules; (3) transparent colorless barite that generated numerous small nests and filled cavities in sediments; (4) yellow barite formed thin (0.5 mm) veins; and (5) white barite cemented small aggregations of coarse-grained sediments. A detailed examination of formation processes of authigenic minerals in the bottom sediment cores allowed to conclude that, there, hydrothermal activity is still going on today. This was confirmed by high methane concentration in near-bottom water above a field of hydrothermal barite minerals.

Nutritional status of lactating mothers and their children 6-23 months of age in pre- and post-harvest seasons in two agro-ecological zones of rural Ethiopia

The objective of this study was to assess seasonal variation in nutritional status and feeding practices among lactating mothers and their children 6-23 months of age in two different agro-ecological zones of rural Ethiopia (lowland zone and midland zone). Food availability and access are strongly affected by seasonality in Ethiopia. However, there are few published data on the effects of seasonal food fluctuations on nutritional status and dietary diversity patterns of mothers and children in rural Ethiopia. A longitudinal study was conducted among 216 mothers in two agro-ecological zones of rural Ethiopia during pre and post-harvest seasons. Data were collected on many parameters including anthropometry, blood levels of haemoglobin and ferritin and zinc, urinary iodine levels, questionnaire data regarding demographic and household parameters and health issues, and infant and young child feeding practices, 24 h food recall to determine dietary diversity scores, and household use of iodized salt. Chi-square and multivariable regression models were used to identify independent predictors of nutritional status. A wide variety of results were generated including the following highlights. It was found that 95.4% of children were breastfed, of whom 59.7% were initially breastfed within one hour of birth, 22.2% received pre-lacteal feeds, and 50.9% of children received complementary feedings by 6 months of age. Iron deficiency was found in 44.4% of children and 19.8% of mothers. Low Zinc status was found in 72.2% of children and 67.3% of mothers. Of the study subjects, 52.5% of the children and 19.1% of the mothers were anaemic, and 29.6% of children and 10.5% of mothers had iron deficiency anaemia. Among the mothers with low serum iron status, 81.2% and 56.2% of their children had low serum zinc and iron, respectively. Similarly, among the low serum zinc status mothers, 75.2% and 45.3% of their children had low serum in zinc and iron, respectively. There was a strong correlation between the micronutrient status of the mothers and the children for ferritin, zinc and haemoglobin (P <0.001). There was also statistically significant difference between agro-ecological zones for micronutrient deficiencies among the mothers (p<0.001) but not for their children. The majority (97.6%) of mothers in the lowland zone were deficient in at least one micronutrient biomarker (zinc or ferritin or haemoglobin). Deficiencies in one, two, or all three biomarkers of micronutrient status were observed in 48.1%, 16.7% and 9.9% of mothers and 35.8%, 29.0%, and 23.5%, of children, respectively. Additionally, about 42.6% of mothers had low levels of urinary iodine and 35.2% of lactating mothers had goitre. Total goitre prevalence rates and urinary iodine levels of lactating mothers were not significantly different across agro-ecological zones. Adequately iodised salt was available in 36.6% of households. The prevalence of anaemia increased from post-harvest (21.8%) to pre-harvest seasons (40.9%) among lactating mothers. Increases were from 8.6% to 34.4% in midland and from 34.2% to 46.3% in lowland agro-ecological zones. Fifteen percent of mothers were anaemic during both seasons. Predictors of anaemia were high parity of mother and low dietary diversity. The proportion of stunted and underweight children increased from 39.8% and 27% in post-harvest season to 46.0% and 31.8% in pre-harvest season, respectively. However, wasting in children decreased from 11.6% to 8.5%. Major variations in stunting and underweight were noted in midland compared to lowland agroecological zones. Anthropometric measurements in mothers indicated high levels of undernutrition. The prevalence of undernutrition in mothers (BMI <18.5kg/m2) increased from 41.7 to 54.7% between post- and pre-harvest seasons. The seasonal effect was generally higher in the midland community for all forms of malnutrition. Parity, number of children under five years and regional variation were predictors of low BMI among lactating mothers. There were differences in minimum meal frequency, minimum acceptable diet and dietary diversity in children in pre-harvest and post-harvest seasons and these parameters were poor in both seasons. Dietary diversity among mothers was higher in lowland zone but was poor in both zones across the seasons. In conclusion, malnutrition and micronutrient deficiencies are very prevalent among lactating mothers and their children 6-23 months old in the study areas. There are significant seasonal variations in malnutrition and dietary diversity, in addition to significant differences between lowland and midland agro-ecological zones. These findings suggest a need to design effective preventive public health nutrition programs to address both the mothers’ and children’s needs particularly in the preharvest season.

Seawater carbonate chemistry, tissue-skeleton interface and calcification in reef corals in a laboratory experiment

Insight into the response of reef corals and other major marine calcifiers to ocean acidification is limited by a lack of knowledge about how seawater pH and carbonate chemistry impact the physiological processes that drive biomineralization. Ocean acidification is proposed to reduce calcification rates in corals by causing declines in internal pH at the calcifying tissue-skeleton interface where biomineralization takes place. Here, we performed an in vivo study on how partial-pressure CO(2)-driven seawater acidification impacts intracellular pH in coral calcifying cells and extracellular pH in the fluid at the tissue-skeleton interface [subcalicoblastic medium (SCM)] in the coral Stylophora pistillata. We also measured calcification in corals grown under the same conditions of seawater acidification by measuring lateral growth of colonies and growth of aragonite crystals under the calcifying tissue. Our findings confirm that seawater acidification decreases pH of the SCM, but this decrease is gradual relative to the surrounding seawater, leading to an increasing pH gradient between the SCM and seawater. Reductions in calcification rate, both at the level of crystals and whole colonies, were only observed in our lowest pH treatment when pH was significantly depressed in the calcifying cells in addition to the SCM. Overall, our findings suggest that reef corals may mitigate the effects of seawater acidification by regulating pH in the SCM, but they also highlight the role of calcifying cell pH homeostasis in determining the response of reef corals to changes in external seawater pH and carbonate chemistry.

Characterization of New Carbosilane Liquid Crystalline Monomers and Dimers

‘De Vries-like’ smectic liquid crystals exhibit low layer contraction of approximately 1% on transitions from the SmA to the SmC phase. These materials have received considerable attention as potential solutions for problems affecting liquid crystal displays using surface-stabilized ferroelectric liquid crystals (SSFLC). In SSFLCs, layer contraction of 710% is normally observed during the SmA to SmC phase transition. A study by the Lemieux group has shown that liquid crystals with nanosegregating carbosilane segments exhibit enhanced ‘de Vries-like’ properties through the formation of smectic layers and by lengthening the nanosegregating carbosilane end-groups from monocarbosilane to tricarbosilane. This observed enhancement is assumed to be due to an increase in the cross-section of the free volume in the hydrocarbon sub-layer. To test this hypothesis, it is assumed that dimers with a tricarbosilane linking group have smaller cross-sections on time average. In his thesis, this hypothesis is tested through the characterization of new liquid crystalline monomers (QL39-n) and dimers (QL40-n) with 2-phenylpyrimidine cores and tricarbosilane end-groups and spacers, respectively. The thesis describes the synthesis of two homologous series of liquid crystals and their characterization using a variety of techniques, including polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. The results show that the monomers QL39-n form a tilted SmC phase only, whereas the dimers QL40-n form an orthogonal SmA phase. These results are discussed in the context of our hypothesis.

Laser IInduced Liinear and Nonlliinear Optiicall Studiies on Certaiin Metall Halliides and Tartrate Crystalls ffor Photoniic Applliicatiions

Nonlinear optics is a broad field of research and technology that encompasses subject matter in the field of Physics, Chemistry, and Engineering. It is the branch of Optics that describes the behavior of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light. This nonlinearity is typically only observed at very high light intensities. This area has applications in all optical and electro optical devices used for communication, optical storage and optical computing. Many nonlinear optical effects have proved to be versatile probes for understanding basic and applied problems. Nonlinear optical devices use nonlinear dependence of refractive index or absorption coefficient on the applied field. These nonlinear optical devices are passive devices and are referred to as intelligent or smart materials owing to the fact that the sensing, processing and activating functions required for optical processes are inherent to them which are otherwise separate in dynamic devices.The large interest in nonlinear optical crystalline materials has been motivated by their potential use in the fabrication of all-optical photonic devices. Transparent crystalline materials can exhibit different kinds of optical nonlinearities which are associated with a nonlinear polarization. The choice of the most suitable crystal material for a given application is often far from trivial; it should involve the consideration of many aspects. A high nonlinearity for frequency conversion of ultra-short pulses does not help if the interaction length is strongly limited by a large group velocity mismatch and the low damage threshold limits the applicable optical intensities. Also, it can be highly desirable to use a crystal material which can be critically phasematched at room temperature. Among the different types of nonlinear crystals, metal halides and tartrates have attracted due to their importance in photonics. Metal halides like lead halides have drawn attention because they exhibit interesting features from the stand point of the electron-lattice interaction .These materials are important for their luminescent properties. Tartrate single crystals show many interesting physical properties such as ferroelectric, piezoelectric, dielectric and optical characteristics. They are used for nonlinear optical devices based on their optical transmission characteristics. Among the several tartrate compounds, Strontium tartrate, Calcium tartrate and Cadmium tartrate have received greater attention on account of their ferroelectric, nonlinear optical and spectral characteristics. The present thesis reports the linear and nonlinear aspects of these crystals and their potential applications in the field of photonics.