36 research outputs found
Part 4: Human Nature Theories of Motivation
At the turn of the 20th century, Frederick Taylors’ Scientific Management Theory dominated the industrial landscape. Managers focused on the best, most efficient ways to accomplish tasks, and viewed workers as replaceable cogs in a machine. But a series of experiments at a factory outside of Chicago led to a new perspective of management and motivation, one that focused on people. This approach, developed by Elton Mayo, established Human Relations Theory and laid the groundwork for future human-nature models to follow, including the Myers-Briggs Type Indicator, Motivation 3.0, and the Golden Circle.https://stars.library.ucf.edu/motivationforpublicservants/1003/thumbnail.jp
Compensation effects in GaN:Mg probed by Raman spectroscopy and photoluminescence measurements
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Appl. Phys. 113, 103504 (2013) and may be found at https://doi.org/10.1063/1.4794094.Compensation effects in metal organic chemical vapour deposition grown GaN doped with magnesium are investigated with Raman spectroscopy and photoluminescence measurements. Examining the strain sensitive E2(high) mode, an increasing compressive strain is revealed for samples with Mg-concentrations lower than 7 × 1018 cm−3. For higher Mg-concentrations, this strain is monotonically reduced. This relaxation is accompanied by a sudden decrease in crystal quality. Luminescence measurements reveal a well defined near band edge luminescence with free, donor bound, and acceptor bound excitons as well as a characteristic donor acceptor pair (DAP) luminescence. Following recent results, three acceptor bound excitons and donor acceptor pairs are identified. Along with the change of the strain, a strong modification in the luminescence of the dominating acceptor bound exciton and DAP luminescence is observed. The results from Raman spectroscopy and luminescence measurements are interpreted as fingerprints of compensation effects in GaN:Mg leading to the conclusion that compensation due to defect incorporation triggered by Mg-doping already affects the crystal properties at doping levels of around 7 × 1018 cm−3. Thereby, the generation of nitrogen vacancies is introduced as the driving force for the change of the strain state and the near band edge luminescence.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement
Temperature dependent photoluminescence of lateral polarity junctions of metal organic chemical vapor deposition grown GaN
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Applied Physics 110, 093503 (2011) and may be found at https://doi.org/10.1063/1.3656987.We report on fundamental structural and optical properties of lateral polarity junctions in GaN. GaN with Ga- to N-polar junctions was grown on sapphire using an AlN buffer layer. Results from scanning electron microscopy and Raman spectroscopy measurements indicate a superior quality of the Ga-polar GaN. An extremely strong luminescence signal is observed at the inversion domain boundary (IDB). Temperature dependent micro photoluminescence measurements are used to reveal the recombination processes underlying this strong emission. At 5 K the emission mainly arises from a stripe along the inversion domain boundary with a thickness of 4-5 μm. An increase of the temperature initially leads to a narrowing to below 2 μm emission area width followed by a broadening at temperatures above 70 K. The relatively broad emission area at low temperatures is explained by a diagonal IDB. It is shown that all further changes in the emission area width are related to thermalization effects of carriers and defects attracted to the IDB. The results are successfully used to confirm a theoretical model for GaN based lateral polarity junctions. Due to the strong and pronounced emission of IDBs even at elevated temperatures, it is demonstrated that lateral polarity junctions exhibit a strong potential for future high efficiency devices.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement
Recommended from our members
Confirmation of Genetic Associations at ELMO1 in the GoKinD Collection Supports Its Role as a Susceptibility Gene in Diabetic Nephropathy
Objective: To examine the association between single nucleotide polymorphisms (SNPs) in the engulfment and cell motility 1 (ELMO1) gene, a locus previously shown to be associated with diabetic nephropathy in two ethnically distinct type 2 diabetic populations, and the risk of nephropathy in type 1 diabetes. Research Design and Methods: Genotypic data from a genome-wide association scan (GWAS) of the Genetics of Kidneys in Diabetes (GoKinD) study collection were analyzed for associations across the ELMO1 locus. In total, genetic associations were assessed using 118 SNPs and 1,705 individuals of European ancestry with type 1 diabetes (885 normoalbuminuric control subjects and 820 advanced diabetic nephropathy case subjects). Results: The strongest associations in ELMO1 occurred at rs11769038 (odds ratio [OR] 1.24; P = 1.7 × 10−3) and rs1882080 (OR 1.23; P = 3.2 × 10−3) located in intron 16. Two additional SNPs, located in introns 18 and 20, respectively, were also associated with diabetic nephropathy. No evidence of association for variants previously reported in type 2 diabetes was observed in our collection. Conclusions: Using GWAS data from the GoKinD collection, we comprehensively examined evidence of association across the ELMO1 locus. Our investigation marks the third report of associations in ELMO1 with diabetic nephropathy, further establishing its role in the susceptibility of this disease. There is evidence of allelic heterogeneity, contributed by the diverse genetic backgrounds of the different ethnic groups examined. Further investigation of SNPs at this locus is necessary to fully understand the commonality of these associations and the mechanism(s) underlying their role in diabetic nephropathy
Protein C deficiency and acute myocardial infarction in the third decade
Protein C deficiency has been associated with a predisposition to venous thrombosis and thromboembolism. Arterial thrombosis has been seen much less frequently and may require other vascular risk factors. Here we describe a young patient with protein C deficiency presenting with an acute myocardial infarction (AMI).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29245/1/0000302.pd
Recommended from our members
Genome-Wide Association Scan for Diabetic Nephropathy Susceptibility Genes in Type 1 Diabetes
OBJECTIVE—Despite extensive evidence for genetic susceptibility
to diabetic nephropathy, the identification of susceptibility
genes and their variants has had limited success. To search for
genes that contribute to diabetic nephropathy, a genome-wide
association scan was implemented on the Genetics of Kidneys in
Diabetes collection.
RESEARCH DESIGN AND METHODS—We genotyped
360,000 single nucleotide polymorphisms (SNPs) in 820 case
subjects (284 with proteinuria and 536 with end-stage renal
disease) and 885 control subjects with type 1 diabetes. Confirmation
of implicated SNPs was sought in 1,304 participants of the
Diabetes Control and Complications Trial (DCCT)/Epidemiology
of Diabetes Interventions and Complications (EDIC) study, a
long-term, prospective investigation of the development of diabetes-
associated complications.
RESULTS—A total of 13 SNPs located in four genomic loci were
associated with diabetic nephropathy with P1105. The
strongest association was at the FRMD3 (4.1 protein ezrin,
radixin, moesin [FERM] domain containing 3) locus (odds ratio
[OR]1.45, P5.0107). A strong association was also
identified at the CARS (cysteinyl-tRNA synthetase) locus (OR
1.36, P3.1106). Associations between both loci and time to
onset of diabetic nephropathy were supported in the DCCT/EDIC
study (hazard ratio [HR]1.33, P0.02, and HR1.32, P
0.01, respectively). We demonstrated expression of both FRMD3
and CARS in human kidney.
CONCLUSIONS—We identified genetic associations for susceptibility
to diabetic nephropathy at two novel candidate loci near
the FRMD3 and CARS genes. Their identification implicates
previously unsuspected pathways in the pathogenesis of this
important late complication of type 1 diabetes
The Transcription Factor SOX18 Regulates the Expression of Matrix Metalloproteinase 7 and Guidance Molecules in Human Endothelial Cells
Mutations in the transcription factor SOX18 are responsible for specific cardiovascular defects in humans and mice. In order to gain insight into the molecular basis of its action, we identified target genes of SOX18 and analyzed one, MMP7, in detail.SOX18 was expressed in HUVEC using a recombinant adenoviral vector and the altered gene expression profile was analyzed using microarrays. Expression of several regulated candidate SOX18 target genes was verified by real-time PCR. Knock-down of SOX18 using RNA interference was then used to confirm the effect of the transcription factor on selected genes that included the guidance molecules ephrin B2 and semaphorin 3G. One gene, MMP7, was chosen for further analysis, including detailed promoter studies using reporter gene assays, electrophoretic mobility shift analysis and chromatin-immunoprecipitation, revealing that it responds directly to SOX18. Immunohistochemical analysis demonstrated the co-expression of SOX18 and MMP7 in blood vessels of human skin.The identification of MMP7 as a direct SOX18 target gene as well as other potential candidates including guidance molecules provides a molecular basis for the proposed function of this transcription factor in the regulation of vessel formation
Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.
OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening
Small Maf Compound Mutants Display Central Nervous System Neuronal Degeneration, Aberrant Transcription, and Bach Protein Mislocalization Coincident with Myoclonus and Abnormal Startle Response
The small Maf proteins form heterodimers with CNC and Bach family proteins to elicit transcriptional responses from Maf recognition elements (MAREs). We previously reported germ line-targeted deficiencies in mafG plus mafK compound mutant mice. The most prominent mutant phenotype was a progressive maf dosage-dependent neuromuscular dysfunction. However, there has been no previous report regarding the effects of altered small-maf gene expression on neurological dysfunction. We show here that MafG and MafK are expressed in discrete central nervous system (CNS) neurons and that mafG::mafK compound mutants display neuronal degeneration coincident with surprisingly selective MARE-dependent transcriptional abnormalities. The CNS morphological changes are concurrent with the onset of a neurological disorder in the mutants, and the behavioral changes are accompanied by reduced glycine receptor subunit accumulation. Bach/small Maf heterodimers, which normally generate transcriptional repressors, were significantly underrepresented in nuclear extracts prepared from maf mutant brains, and Bach proteins fail to accumulate normally in nuclei. Thus compound mafG::mafK mutants develop age- and maf gene dosage-dependent cell-autonomous neuronal deficiencies that lead to profound neurological defects
Phytochemical analysis, antioxidant and anti-inflammatory potential of FERETIA APODANTHERA root bark extracts
Abstract Background Inflammation has been implicated in many disorders, including cancer and available therapies elicit adverse effects. Plants of the family Rubiaceae have shown potency against inflammation. The anti-inflammatory and anti-oxidant potential of Feretia apodanthera was investigated in this study to evaluate its effectiveness. Methods The phytochemical, antioxidant and anti-inflammatory potential of root bark (n-Hexane, diethyl ether, ethanol and aqueous) extracts of Feretia apodanthera was investigated in this study. The extracts were subjected to various chemical tests for phytochemical constituents; their antioxidant activity was determined using in-vitro DPPH radical scavenging activity assay and their anti-inflammatory activity was determined using carrageenan induced paw oedema model. FTIR and GCMS analysis was done to determine the compounds present. Results Phytochemical screening of extracts revealed the presence of unsaturated steroids, triterpenes, cardiac glycosides, tannins, saponin and alkaloids. Vitamin C had a median inhibitory concentration (IC50) of 0.038 mg/ml which was lower than IC50 of all the extracts. Of all the extracts, ethanol extract had the lowest IC50 (0.044 mg/ml) which is comparable to vitamin C. Anti-inflammatory studies showed that the inflammation inhibition potential of 400 mg/kg body weight of all the extracts was significantly lower (p < 0.05) than the standard ketoprofen (50 mg/kg) at the first three hours but significantly higher (p < 0.05) at the fourth hour. At the fifth hour, the inflammation inhibition potential of diethyl ether, ethanol and aqueous extracts were significantly higher (p < 0.05) than that of the standard. FTIR analysis showed the presence of ketones, amines, alkenes and carboxylic groups. GCMS analysis revealed compounds that are potential anti-inflammatory agents. Conclusion This study revealed that extracts of Feretia apodanthera possess anti-inflammatory effects against right hind paw oedema of albino rats and can act as an effective antioxidant