103 research outputs found
Origin and age of the Eisenkappel gabbro to granite suite (Carinthia, SE Austrian Alps)
AbstractThe northern part of the Karawanken plutonic belt is a gabbroβgranite complex located just north of the Periadriatic lineament near the SlovenianβAustrian border. Petrographic and geochemical studies of the Eisenkappel intrusive complex indicate that this multiphase plutonic suite developed by a combination of crystal accumulation, fractional crystallization and assimilation processes, magma mixing and mingling. The mafic rocks are alkaline and have within-plate geochemical characteristics, indicating anorogenic magmatism in an extensional setting and derivation from an enriched mantle source. The mafic melts triggered partial melting of the crust and the formation of granite. The granitic rocks are alkalic, metaluminous and have the high Fe/Fe+Mg characteristics of within-plate plutons. Temperature and pressure conditions, derived from amphibole-plagioclase and different amphibole thermobarometers, suggest that the analysed Eisenkappel gabbros crystallized at around 1000Β±20Β°C and 380β470MPa, whereas the granitic rock crystallized at Tβ€800Β±20Β°C andβ€350MPa. Mineral-whole rock SmβNd analyses of two cumulate gabbros yielded 249Β±8.4Ma and 250Β±26Ma (Ξ΅Nd: +3.6), garnet-whole rock SmβNd analyses of two silicic samples yielded well-constrained ages of 238.4Β±1.9Ma and 242.1Β±2.1Ma (Ξ΅Nd: β2.6)
Low-Key Stationary and Mobile Tools for Probing the Atmospheric UHI Effect
The urban heat island (UHI) effect is created by a series of man-made surface modifications in urban areas that cause changes to the surface energy balance, resulting in higher urban surface air temperatures as compared with surrounding rural areas. Studying the UHI effect is highly amenable to hands-on undergraduate student research projects, because, among other reasons, there are low key measurement tools that allow accurate and regular stationary and mobile probing of air temperature. Here, we summarize the results of a student project at Texas A&M University that analyzed the atmospheric UHI of Bryan/College Station, a mid-size metro area in east Texas. Sling psychrometers were used for semi-regular twice daily stationary air temperature monitoring, and a low-cost electronic sensor and miniature data logger were used for mobile measurements. Stationary data from two similar, open mid-rise building locations showed typical UHI intensities of 0β2Β°C, while the mobile measurements identified situations with UHI intensities exceeding 6Β°C when traversing areas with high impervious surface fractions. Nighttime measurements showed the expected UHI intensity relations to wind speed and atmospheric pressure, while daytime data were more strongly related to urban morphology. The success of this research may encourage similar student projects that deliver baseline data to urban communities seeking to mitigate the UHI
Association of Cardiometabolic Genes with Arsenic Metabolism Biomarkers in American Indian Communities: The Strong Heart Family Study (SHFS)
BACKGROUND: Metabolism of inorganic arsenic (iAs) is subject to inter-individual variability, which is explained partly by genetic determinants.
OBJECTIVES: We investigated the association of genetic variants with arsenic species and principal components of arsenic species in the Strong Heart Family Study (SHFS).
METHODS: We examined variants previously associated with cardiometabolic traits (~ 200,000 from Illumina Cardio MetaboChip) or arsenic metabolism and toxicity (670) among 2,428 American Indian participants in the SHFS. Urine arsenic species were measured by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), and percent arsenic species [iAs, monomethylarsonate (MMA), and dimethylarsinate (DMA), divided by their sum Γ 100] were logit transformed. We created two orthogonal principal components that summarized iAs, MMA, and DMA and were also phenotypes for genetic analyses. Linear regression was performed for each phenotype, dependent on allele dosage of the variant. Models accounted for familial relatedness and were adjusted for age, sex, total arsenic levels, and population stratification. Single nucleotide polymorphism (SNP) associations were stratified by study site and were meta-analyzed. Bonferroni correction was used to account for multiple testing.
RESULTS: Variants at 10q24 were statistically significant for all percent arsenic species and principal components of arsenic species. The index SNP for iAs%, MMA%, and DMA% (rs12768205) and for the principal components (rs3740394, rs3740393) were located near AS3MT, whose gene product catalyzes methylation of iAs to MMA and DMA. Among the candidate arsenic variant associations, functional SNPs in AS3MT and 10q24 were most significant (p < 9.33 Γ 10-5).
CONCLUSIONS: This hypothesis-driven association study supports the role of common variants in arsenic metabolism, particularly AS3MT and 10q24. Citation: Balakrishnan P, Vaidya D, Franceschini N, Voruganti VS, Gribble MO, Haack K, Laston S, Umans JG, Francesconi KA, Goessler W, North KE, Lee E, Yracheta J, Best LG, MacCluer JW, Kent J Jr., Cole SA, Navas-Acien A. 2017. Association of cardiometabolic genes with arsenic metabolism biomarkers in American Indian communities: the Strong Heart Family Study (SHFS). Environ Health Perspect 125:15-22;βhttp://dx.doi.org/10.1289/EHP251
The effect of an external magnetic force on cell adhesion and proliferation of magnetically labeled mesenchymal stem cells
<p>Abstract</p> <p>Background</p> <p>As the strategy for tissue regeneration using mesenchymal stem cells (MSCs) for transplantation, it is necessary that MSCs be accumulated and kept in the target area. To accumulate MSCs effectively, we developed a novel technique for a magnetic targeting system with magnetically labeled MSCs and an external magnetic force. In this study, we examined the effect of an external magnetic force on magnetically labeled MSCs in terms of cell adhesion and proliferation.</p> <p>Methods</p> <p>Magnetically labeled MSCs were plated at the bottom of an insert under the influence of an external magnetic force for 1 hour. Then the inserts were turned upside down for between 1 and 24 hours, and the number of MSCs which had fallen from the membrane was counted. The gene expression of MSCs affected magnetic force was analyzed with microarray. In the control group, the same procedure was done without the external magnetic force.</p> <p>Results</p> <p>At 1 hour after the inserts were turned upside down, the average number of fallen MSCs in the magnetic group was significantly smaller than that in the control group, indicating enhanced cell adhesion. At 24 hours, the average number of fallen MSCs in the magnetic group was also significantly smaller than that in control group. In the magnetic group, integrin alpha2, alpha6, beta3 BP, intercellular adhesion molecule-2 (ICAM-2), platelet/endothelial cell adhesion molecule-1 (PECAM-1) were upregulated. At 1, 2 and 3 weeks after incubation, there was no statistical significant difference in the numbers of MSCs in the magnetic group and control group.</p> <p>Conclusions</p> <p>The results indicate that an external magnetic force for 1 hour enhances cell adhesion of MSCs. Moreover, there is no difference in cell proliferation after using an external magnetic force on magnetically labeled MSCs.</p
Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study
Cadmium (Cd) is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of Cd with hypertension has been inconsistent. We studied the association between urinary Cd concentrations, a measure of total body burden, and blood pressure in American Indians, a US population with above national average Cd burden. Urinary Cd was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking antihypertensive medications), urinary Cd ranged from 0.01 to 78.48βΞΌgβg creatinine (geometric mean=0.94βΞΌgβg) and it was correlated with smoking pack-year among ever-smokers (r=0.16, P<0.0001). Participants who were smokers were on average light-smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88βΞΌgβg creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration (Ξ²)=1.64, P=0.002). These associations were present among light- and never-smokers (Ξ²=2.03, P=0.002, n=2627), although not significant among never-smokers (Ξ²=1.22, P=0.18, n=1260). Cd was also associated with diastolic blood pressure among light- and never-smokers (Ξ²=0.94, P=0.004). These findings suggest that there is a relationship between Cd body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk.This research is supported by the NHLBI HL123677-02 to NF and the NIEHS training grant (ES007141-32) to PB. MTP was supported by the Strategic Action for Research in Health sciences [CP12/03080], which is an initiatives from Carlos III Health Institute Madrid and the Spanish Ministry of Economy and Competitiveness and are co-funded with European Funds for Regional Development (FEDER)
Heritability and Preliminary Genome-Wide Linkage Analysis of Arsenic Metabolites in Urine
Background: Arsenic (III) methyltransferase (AS3MT) has been related to urine arsenic metabolites in association studies. Other genes might also play roles in arsenic metabolism and excretion
Tissue engineering of functional articular cartilage: the current status
Osteoarthritis is a degenerative joint disease characterized by pain and disability. It involves all ages and 70% of people aged >65 have some degree of osteoarthritis. Natural cartilage repair is limited because chondrocyte density and metabolism are low and cartilage has no blood supply. The results of joint-preserving treatment protocols such as debridement, mosaicplasty, perichondrium transplantation and autologous chondrocyte implantation vary largely and the average long-term result is unsatisfactory. One reason for limited clinical success is that most treatments require new cartilage to be formed at the site of a defect. However, the mechanical conditions at such sites are unfavorable for repair of the original damaged cartilage. Therefore, it is unlikely that healthy cartilage would form at these locations. The most promising method to circumvent this problem is to engineer mechanically stable cartilage ex vivo and to implant that into the damaged tissue area. This review outlines the issues related to the composition and functionality of tissue-engineered cartilage. In particular, the focus will be on the parameters cell source, signaling molecules, scaffolds and mechanical stimulation. In addition, the current status of tissue engineering of cartilage will be discussed, with the focus on extracellular matrix content, structure and its functionality
Mesodermal fate decisions of a stem cell: the Wnt switch
Stem cells are a powerful resource for cell-based transplantation therapies in osteodegenerative disorders, but before some kinds of stem cells can be applied clinically, several aspects of their expansion and differentiation need to be better controlled. Wnt molecules and members of the Wnt signaling cascade have been ascribed a role in both these processes in vitro as well as normal development in vivo. However some results are controversial. In this review we will present the hypothesis that both canonical and non-canonical signaling are involved in mesenchymal cell fate regulation, such as adipogenesis, chondrogenesis and osteogenesis, and that in vitro it is a timely switch between the two that specifies the identity of the differentiating cell. We will specifically focus on the in vitro differentiation of adipocytes, chondrocytes and osteoblasts contrasting embryonic and mesenchymal stem cells as well as the role of Wnts in mesenchymal fate specification during embryogenesis
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