5,453 research outputs found
Local spin fluctuations in iron-based superconductors: 77Se and 87Rb NMR measurements of Tl0.47Rb0.34Fe1.63Se2
We report nuclear magnetic resonance (NMR) studies of the intercalated iron
selenide superconductor (Tl, Rb)FeSe ( K).
Single-crystal measurements up to 480 K on both Se and Rb nuclei
show a superconducting phase with no magnetic order. The Knight shifts and
relaxation rates increase very strongly with temperature above ,
before flattening at 400 K. The quadratic -dependence and perfect
proportionality of both and data demonstrate their origin in
paramagnetic moments. A minimal model for this pseudogap-like response is not a
missing density of states but two additive contributions from the itinerant
electronic and local magnetic components, a framework unifying the and
data in many iron-based superconductors
Fabrication of functionally graded 3A/5A zeolites by electrophoretic deposition
Functionally graded zeolites of molecular sieve type 3A and 5A are deposited by electrophoretic deposition (EPD) from acetone suspension with 8% volume concentration of n-butylamine as particle charging agent. The EPD characteristics of both 3A and 5A suspensions are studied. Functionally graded zeolite 3A/5A deposits are obtained at 200 V DC. Energy dispersive X-ray dispersion (EDX) analysis results confirm the graded structure. The deposited zeolites are also analysed by scanning electron microscopy (SEM). The factors influencing the deposition process are discussed
Pvt1-encoded microRNAs in oncogenesis
<p>Abstract</p> <p>Background</p> <p>The functional significance of the <it>Pvt1 </it>locus in the oncogenesis of Burkitt's lymphoma and plasmacytomas has remained a puzzle. In these tumors, <it>Pvt1 </it>is the site of reciprocal translocations to immunoglobulin loci. Although the locus encodes a number of alternative transcripts, no protein or regulatory RNA products were found. The recent identification of non-coding microRNAs encoded within the <it>PVT1 </it>region has suggested a regulatory role for this locus.</p> <p>Results</p> <p>The mouse <it>Pvt1 </it>locus encodes several microRNAs. In mouse T cell lymphomas induced by retroviral insertions into the locus, the <it>Pvt1 </it>transcripts, and at least one of their microRNA products, mmu-miR-1204 are overexpressed. Whereas up to seven co-mutations can be found in a single tumor, in over 2,000 tumors none had insertions into both the <it>Myc </it>and <it>Pvt1 </it>loci.</p> <p>Conclusion</p> <p>Judging from the large number of integrations into the <it>Pvt1 </it>locus – more than in the nearby <it>Myc </it>locus – <it>Pvt1 </it>and the microRNAs encoded by it are as important as <it>Myc </it>in T lymphomagenesis, and, presumably, in T cell activation. An analysis of the co-mutations in the lymphomas likely place <it>Pvt1 </it>and <it>Myc </it>into the same pathway.</p
Retroviral activation of the mir-106a microRNA cistron in T lymphoma
Retroviral insertion into a host genome is a powerful tool not only for the discovery of cancer genes, but also for the discovery of potential oncogenic noncoding RNAs. In a large-scale mouse T lymphocyte tumor screen we found a high density of integrations upstream of the mir-106a microRNA cistron. In tumors containing an integration, the primary transcript encoding the mir-106a cistron was overexpressed five to 20-fold compared with that of control tumors; concomitantly, the mature mir-106a and mir-363 microRNAs were highly overexpressed as well. These findings suggest the mir-106a cistron plays an important role in T cell tumorigenesis
Sepsis-Induced Glomerular Endothelial Dysfunction Mediates Reductions in GFR and Increases in Protein Filtration
poster abstractBackground: Sepsis is now the leading cause of acute kidney injury (AKI) known to decrease Glomerular filtration rate (GFR) and increase proteinuria. There also exists a discrepancy between renal perfusion and GFR. Methods: To evaluate the potential role of the glomerulus in the overall pathogenesis of these abnormalities, we studied surface glomeruli in 8-10 week old Munich Wistar Frmter rats using intravital 2-photon microscopy in a cecal ligation and puncture (CLP) model of sepsis to ask targeted questions and compare the metric of measured GFR to serum creatinine changes at 24 hours post CLP. Results: Male rats undergoing CLP showed an increase in serum creatinine from 0.23 +/- 0.06 mg/dl to 0.80 +/-0.17 (P0.01) and a decrease in real time GFR from 0.69 +/- 0.06 ml/min/100gm body wt to 0.34 +/-0.15 (P0.01). Hemodynamic monitoring revealed normal and hyperdynamic cardiac status within the CLP group. Quantitative analysis of 15 glomeruli in three CLP septic rats revealed a reduction in red blood cell flow rates within capillary loops from 1,771 +/- 467 to 576 +/- 327 um/sec (P0.01); an increase in WBC adherence to glomerular capillary endothelial cells from 0.42 +/-0.33 to 7.25 +/- 5.82 WBC's/standardized glomerular volume (P0.05) in CLP rats; and an increase in the glomerular sieving coefficient (GSC) of a 150kD dextran from 0.007 +/- 0.003 to 0.097 +/- 0.046 (P0.05). Rouleaux formations were seen only in septic rats. Conclusions: These data indicate glomerular endothelial-WBC interactions during sepsis, in part, explain the reduction in GFR and increased filtration of large molecular weight proteins. The results from real time GFR accurately detected the drop in renal function for this model of sepsis
Development of a microwave-based extraction for forensic biological samples
In this study, a quick microwave-based treatment was developed as a front end for DNA analysis of forensic samples. The effect of microwave treatment is to cause cell disruption which can improve the release of DNA during direct PCR as well as with extraction methods. Exposure to microwave preprocessing improved the quality of rapid genotyping, particularly when used with low level samples. Optimal results were obtained when samples were microwaved at 300W for 40 s, resulting in improved allele detection. Overall, the addition of this simple preprocessing step improves sensitivity and allele recovery for low level DNA samples when combined with expedited DNA analysis workflows. Its main advantages include speed, low cost, compatibility with downstream DNA methods and application to a wide variety of samples
Morphological Assessment of Basic Multicellular Unit Resorption Parameters in Dogs Shows Additional Mechanisms of Bisphosphonate Effects on Bone
Bisphosphonates (BPs) slow bone loss by reducing initiation of new basic multicellular units (BMUs). Whether or not BPs simply prevent osteoclasts from initiating new BMUs that resorb bone or also reduce the amount of bone they resorb at the BMU level is not clear. The goal of this study was to determine the effects of BPs on three morphological parameters of individual BMUs, resorption depth (Rs.De), area (Rs.Ar), and width (Rs.Wi). After 1 year of treatment with vehicle (VEH), alendronate (ALN; 0.10, 0.20, or 1.00 mg/kg/day), or risedronate (RIS; 0.05, 0.10, or 0.50 mg/kg/day), resorption cavity morphology was assessed in vertebral trabecular bone of beagle dogs by histology. Animals treated with ALN or RIS at the doses representing those used to treat postmenopausal osteoporosis (0.20 and 0.10 mg/kg/day, respectively) had significantly lower Rs.Ar (−27%) and Rs.Wi (−17%), with no difference in Rs.De, compared to VEH-treated controls. Low doses of ALN and RIS did not affect any parameters, whereas higher doses resulted in similar changes to those of the clinical dose. There were no significant differences in the resorption cavity measures between RIS and ALN at any of the dose equivalents. These results highlight the importance of examining parameters beyond erosion depth for assessment of resorption parameters. Furthermore, these results suggest that in addition to the well-known effects of BPs on reducing the number of active BMUs, these drugs also reduce the activity of osteoclasts at the individual BMU level at doses at and above those used clinically for the treatment of postmenopausal osteoporosis
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