122 research outputs found
Spin relaxation in a germanium nanowire
We report experimental study of spin transport in nanowirespin valve structures consisting of three layers—cobalt, germanium, and nickel. The spin diffusion length in the Ge is estimated to be about 400nm at 1.9K and the corresponding spin relaxation time is about 4ns. At 100K, the spin diffusion length drops to 180nm and the relaxation time is about 0.81ns. These short relaxation times, which depend weakly on temperature, are caused by strong surface roughness scattering that causes rapid spin relaxation via the Elliott-Yafet mode [Elliott, Phys. Rev.96, 266 (1954)]
A SimRank based Ensemble Method for Resolving Challenges of Partition Clustering Methods
323–327Traditional clustering techniques alone cannot resolve all challenges of partition-based clustering methods. In the partition based clustering, particularly in variants of K-means, initial cluster centre selection is a significant and crucial point. The dependency of final cluster is totally based on initial cluster centres; hence, this process is delineated to be most significant in the entire clustering operation. The random selection of initial cluster centres is unstable, since different cluster centre points are achieved during each run of the algorithm. Ensemble based clustering methods resolve challenges of partition-based methods. The clustering ensembles join several partitions generated by different clustering algorithms into a single clustering solution. The proposed ensemble methodology resolves initial centroid problems and improves the efficiency of cluster results. This method finds centroid selection through overall mean distance measure. The SimRank based similarity matrix find that the bipartite graph helps to ensemble
Management of Pulmonary Hypertension From Left Heart Disease in Candidates for Orthotopic Heart Transplantation
Pulmonary hypertension in left heart disease (PH-LHD) commonly complicates prolonged heart failure (HF). When advanced, the PH becomes fixed or out of proportion and is associated with increased morbidity and mortality in patients undergoing orthotopic heart transplant (OHT). To date, the only recommended treatment of out of proportion PH is the treatment of the underlying HF by reducing the pulmonary capillary wedge pressure (PCWP) with medications and often along with use of mechanical circulatory support. Medical therapies typically used in the treatment of World Health Organization (WHO) group 1 pulmonary arterial hypertension (PAH) have been employed off-label in the setting of PH-LHD with varying efficacy and often negative outcomes. We will discuss the current standard of care including treating HF and use of mechanical circulatory support. In addition, we will review the studies published to date assessing the efficacy and safety of PAH medications in patients with PH-LHD being considered for OHT
A SimRank based Ensemble Method for Resolving Challenges of Partition Clustering Methods
Traditional clustering techniques alone cannot resolve all challenges of partition-based clustering methods. In the partition based clustering, particularly in variants of K-means, initial cluster centre selection is a significant and crucial point. The dependency of final cluster is totally based on initial cluster centres; hence, this process is delineated to be most significant in the entire clustering operation. The random selection of initial cluster centres is unstable, since different cluster centre points are achieved during each run of the algorithm. Ensemble based clustering methods resolve challenges of partition-based methods. The clustering ensembles join several partitions generated by different clustering algorithms into a single clustering solution. The proposed ensemble methodology resolves initial centroid problems and improves the efficiency of cluster results. This method finds centroid selection through overall mean distance measure. The SimRank based similarity matrix find that the bipartite graph helps to ensemble
Case report on renal failure reversal in lambda chain multiple myeloma with bortezomib and dexamethasone
Renal failure (RF) reversal in multiple myeloma (MM) is associated with an improved prognosis. Light chain myeloma, serum creatinine (SCr) \u3e 4 mg/dL, extensive proteinuria, early infections, and certain renal biopsy findings are associated with lower rates of RF reversal. Our patient is a 67-year-old female with multiple poor prognostic factors for RF reversal who demonstrated a rapid renal response with bortezomib and dexamethasone (BD) regimen. She presented initially with altered mental status. On exam, she appeared lethargic and dehydrated and had generalized tenderness. She had been taking ibuprofen as needed for pain for a few weeks. Labs showed a white cell count-18,900/muL with no bandemia, hemoglobin 10.8 gm/dL, potassium-6.7 mEq/L, bicarbonate-15 mEq/L, blood urea nitrogen-62 mg/dL, SCr-5.6 mg/dL (baseline: 1.10), and corrected calcium-11.8 mg/dL. A rapid flu test was positive. Imaging studies were unremarkable. Her EKG showed sinus tachycardia and her urinalysis was unremarkable. The unexplained RF in an elderly individual in conjunction with hypercalcemia and anemia prompted a MM work-up; eventually, lambda variant MM was diagnosed. An immediate (4 days) renal response defined as 50% reduction in SCr was noticed after initiation of the BD regimen
Polymorphisms of TNF-enhancer and gene for FcγRIIa correlate with the severity of falciparum malaria in the ethnically diverse Indian population
<p>Abstract</p> <p>Background</p> <p>Susceptibility/resistance to <it>Plasmodium falciparum </it>malaria has been correlated with polymorphisms in more than 30 human genes with most association analyses having been carried out on patients from Africa and south-east Asia. The aim of this study was to examine the possible contribution of genetic variants in the <it>TNF </it>and <it>FCGR2A </it>genes in determining severity/resistance to <it>P. falciparum </it>malaria in Indian subjects.</p> <p>Methods</p> <p>Allelic frequency distribution in populations across India was first determined by typing genetic variants of the <it>TNF </it>enhancer and the <it>FCGR2A </it>G/A SNP in 1871 individuals from 55 populations. Genotyping was carried out by DNA sequencing, single base extension (SNaPshot), and DNA mass array (Sequenom). Plasma TNF was determined by ELISA. Comparison of datasets was carried out by Kruskal-Wallis and Mann-Whitney tests. Haplotypes and LD plots were generated by PHASE and Haploview, respectively. Odds ratio (OR) for risk assessment was calculated using EpiInfo™ version 3.4.</p> <p>Results</p> <p>A novel single nucleotide polymorphism (SNP) at position -76 was identified in the <it>TNF </it>enhancer along with other reported variants. Five <it>TNF </it>enhancer SNPs and the <it>FCGR2A </it>R131H (G/A) SNP were analyzed for association with severity of <it>P. falciparum </it>malaria in a malaria-endemic and a non-endemic region of India in a case-control study with ethnically-matched controls enrolled from both regions. <it>TNF </it>-1031C and -863A alleles as well as homozygotes for the TNF enhancer haplotype CACGG (-1031T>C, -863C>A, -857C>T, -308G>A, -238G>A) correlated with enhanced plasma TNF levels in both patients and controls. Significantly higher TNF levels were observed in patients with severe malaria. Minor alleles of -1031 and -863 SNPs were associated with increased susceptibility to severe malaria. The high-affinity IgG2 binding FcγRIIa AA (131H) genotype was significantly associated with protection from disease manifestation, with stronger association observed in the malaria non-endemic region. These results represent the first genetic analysis of the two immune regulatory molecules in the context of <it>P. falciparum </it>severity/resistance in the Indian population.</p> <p>Conclusion</p> <p>Association of specific <it>TNF </it>and <it>FCGR2A </it>SNPs with cytokine levels and disease severity/resistance was indicated in patients from areas with differential disease endemicity. The data emphasizes the need for addressing the contribution of human genetic factors in malaria in the context of disease epidemiology and population genetic substructure within India.</p
How hybrids manage growth and social–business tensions in global supply chains: the case of impact sourcing
This study contributes to the growing interest in how hybrid organizations manage paradoxical social–business tensions. Our empirical case is ‘‘impact sourcing’’— hybrids in global supply chains that hire staff from disadvantaged communities to provide services to business clients. We identify two major growth orientations— ‘‘community-focused’’ and ‘‘client-focused’’ growth—their inherent tensions and ways that hybrids manage them. The former favors slow growth and manages tensions through highly integrated client and community relations; the latter promotes faster growth and manages client and community relations separately. Both growth orientations address social–business tensions in particular ways, but also create latent constraints that manifest when entrepreneurial aspirations conflict with the current growth path. In presenting and discussing our findings, we introduce preempting management practices of tensions, and the importance of geographic embeddedness and distance to the paradox literature
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