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Sample records for mehr als nur

  1. Lop Nur, Xinjiang, China

    NASA Image and Video Library

    2017-09-27

    NASA image acquired May 17, 2011 Located in China’s resource-rich but moisture-poor Xinjiang autonomous region, Lop Nur is an uninviting location for any kind of agriculture. It sits at the eastern end of the Taklimakan Desert, where marching sand dunes can reach heights of 200 meters (650 feet), and dust storms rage across the landscape. Yet for all it lacks in agricultural appeal, Lop Nur offers something valuable to farmers the world over: potash. This potassium salt provides a major nutrient required for plant growth, making it a key ingredient in fertilizer. The discovery of potash at Lop Nur in the mid-1990s turned the area into a large-scale mining operation. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image of Lop Nur on May 17, 2011. The rectangular shapes in this image show the bright colors characteristic of solar evaporation ponds. Around the evaporation ponds are the earth tones typical of sandy desert. During the early and middle Pleistocene epoch, this area held a large brackish lake. Uplift of the northern part of the lake in the late Pleistocene created hollows that became receptacles for potash deposition. The main potash deposits found at Lop Nur today are brine potash, and this site is the second-largest source of potash in China. Lop Nur slowly dried up in the Holocene. The area now receives average annual precipitation of just 31.2 millimeters (1.2 inches), and experiences annual evaporation of 2,901 millimeters (114 inches), according to a study published in 2008. The study found, however, that this area has experienced seven major climate changes since the end of the Pleistocene, including climatic conditions far more favorable to farming and settlement than today. Examination of plant and mollusk remains at the lake, as well as studies of sediments, indicate that the Lop Nur region experienced a severe drought about 3,000 years ago, followed by wetter conditions. Between 1

  2. Research progress in China's Lop Nur

    NASA Astrophysics Data System (ADS)

    Dong, Zhibao; Lv, Ping; Qian, Guangqiang; Xia, Xuncheng; Zhao, Yuanje; Mu, Guijin

    2012-02-01

    China's Lop Nur is one of the world's largest playas, and is located in the driest part of Central Asia. Scientific explorations by Chinese and foreign researchers have been continuously conducted there since the mid- to late 1800 s, and much progress has been made, but many issues remain hotly debated. Particularly intense debate focuses on the formation, environmental evolution, drying date of the Lop Nur lake, and cause of the helical salt crusts recently revealed by remote-sensing images. In this paper, we review the status of this research to provide insights that can inform studies in other arid zones that resemble the Lop Nur. The Lop Nur depression is a secondary unit of the Tarim Block, controlled by faults and fractures formed by the Himalayan orogeny, but various competing explanations have been proposed for how these geological structures gave rise to the depression. The depression's formation date also remains unclear. Several boreholes have been created to reconstruct the environmental evolution at different time scales since the Quaternary, and deposition rates of lake sediments, especially since the Late Pleistocene, have averaged less than 1 mm annually. The drying date of the Lop Nur lake is also debated. The helical salt crust structures appear to have formed as the lake shrank, but how and when they formed is unclear. Huge potash reserves have been found, and large-scale potash fertilizer production has begun, but the origin of these deposits is debated. Understanding the factors causing environmental evolution in this region is a central issue that will help us to clarify these and other debated issues.

  3. Nur77 Regulates Nondeletional Mechanisms of Tolerance in T Cells.

    PubMed

    Hu, Qian Nancy; Suen, Alexander Y W; Henao Caviedes, Laura M; Baldwin, Troy A

    2017-09-25

    Negative selection against highly self-reactive thymocytes is critical for preventing autoimmunity. Thymocyte deletion, anergy induction, and agonist selection are all forms of negative selection that can occur following a high-affinity TCR signal. Of Bim and Nur77, two TCR-induced proteins with proapoptotic function, Bim has been shown to be important for clonal deletion in several model systems, whereas Nur77 was often dispensable. However, Nur77 has been reported to influence other aspects of T cell development by mechanisms that may not be related to its proapoptotic function. In this study, we examined the role of Nur77 during thymocyte development in the presence and absence of Bim to separate apoptotic from nonapoptotic functions of Nur77. Polyclonal Bim(-/-) and Bim(-/-)Nur77(-/-) mice exhibited comparable accumulation of high-affinity signaled CD4(+)CD8(+) double-positive thymocytes and CD8(+) and CD4(+) single-positive thymocytes. However, combined Bim and Nur77 deficiency increased the frequency of thymic Foxp3(+) T regulatory cells and Foxp3(-)FR4(hi)CD73(hi) anergic phenotype CD4(+) T cells compared with Bim(-/-) mice, suggesting that Nur77 expression impairs the development of nonconventional tolerance-inducing cell fates. Using the OT-I RIP-mOVA model, we found that Nur77 deficiency did not substantially impact clonal deletion nor did it exacerbate the defect in clonal deletion in the absence of Bim. However, additional loss of Nur77 in the absence of Bim led to diabetes induction, suggesting that Nur77 promotes tolerance in this context. Together, these data reveal novel nondeletional roles for Nur77 that differ between T cell subsets and have implications for self-tolerance. Copyright © 2017 by The American Association of Immunologists, Inc.

  4. Orphan nuclear receptor Nur77 affects cardiomyocyte calcium homeostasis and adverse cardiac remodelling.

    PubMed

    Medzikovic, Lejla; Schumacher, Cees A; Verkerk, Arie O; van Deel, Elza D; Wolswinkel, Rianne; van der Made, Ingeborg; Bleeker, Natascha; Cakici, Daniella; van den Hoogenhof, Maarten M G; Meggouh, Farid; Creemers, Esther E; Remme, Carol Ann; Baartscheer, Antonius; de Winter, Robbert J; de Vries, Carlie J M; Arkenbout, E Karin; de Waard, Vivian

    2015-10-21

    Distinct stressors may induce heart failure. As compensation, β-adrenergic stimulation enhances myocardial contractility by elevating cardiomyocyte intracellular Ca(2+) ([Ca(2+)]i). However, chronic β-adrenergic stimulation promotes adverse cardiac remodelling. Cardiac expression of nuclear receptor Nur77 is enhanced by β-adrenergic stimulation, but its role in cardiac remodelling is still unclear. We show high and rapid Nur77 upregulation in cardiomyocytes stimulated with β-adrenergic agonist isoproterenol. Nur77 knockdown in culture resulted in hypertrophic cardiomyocytes. Ventricular cardiomyocytes from Nur77-deficient (Nur77-KO) mice exhibited elevated diastolic and systolic [Ca(2+)]i and prolonged action potentials compared to wild type (WT). In vivo, these differences resulted in larger cardiomyocytes, increased expression of hypertrophic genes, and more cardiac fibrosis in Nur77-KO mice upon chronic isoproterenol stimulation. In line with the observed elevated [Ca(2+)]i, Ca(2+)-activated phosphatase calcineurin was more active in Nur77-KO mice compared to WT. In contrast, after cardiac pressure overload by aortic constriction, Nur77-KO mice exhibited attenuated remodelling compared to WT. Concluding, Nur77-deficiency results in significantly altered cardiac Ca(2+) homeostasis and distinct remodelling outcome depending on the type of insult. Detailed knowledge on the role of Nur77 in maintaining cardiomyocyte Ca(2+) homeostasis and the dual role Nur77 plays in cardiac remodelling will aid in developing personalized therapies against heart failure.

  5. The Holocene history of Lop Nur and its palaeoclimate implications

    NASA Astrophysics Data System (ADS)

    Liu, Chenglin; Zhang, Jia-Fu; Jiao, Pengcheng; Mischke, Steffen

    2016-09-01

    The Holocene hydrological history of Lop Nur in northwestern China's Tarim Basin and its response to climate conditions are inferred from a relatively well-dated multi-proxy record including grain-size, pollen and spores, and soluble salt data. A dated pit section (YKD0301) with a depth of 570 cm in the center of the dry Lop Nur Basin was investigated. The sediments contain a total of twenty fining-upward cycles as a result of strong discharge from the catchment to the lake during relatively wet conditions. The fluvial sediments were probably widely dispersed by wind-driven waves and currents in the large and shallow basin of Lop Nur. Higher runoff and dilution of lake waters are also indicated by lower contents of soluble salt in the sediments and recorded ostracod shells of brackish and oligohaline to freshwater species. In contrast, sediment sections with smaller mean grain size and fewer flood layers are dominated by aeolian sediments which were accumulated during drier periods. Ostracod shells are mostly lacking from these sections, suggesting a higher salinity in the lake. Lop Nur experienced six stages during the last 9 ka. Relatively wet conditions existed between 9.0-8.9, 8.7-5.1 and 2.4-1.8 ka, with periods of increased aridity in between and after 1.8 ka. The lowest salinity was recorded between 8.7 and 5.1 ka which represents the wettest phase during the last 9 ka and probably the regional Holocene Optimum. Relatively wet climate conditions between 2.4 and 1.8 ka and dry conditions afterwards possibly first fostered and later on caused the devastation of the ancient Loulan Kingdom in the region. The uppermost sediments of the section represent a massive salt crust formed during the final desiccation of the lake in the last century. The effective moisture change pattern of the Lop Nur region is roughly consistent with synthesized Holocene moisture records for western China dominated by the westerlies.

  6. Nur77 forms novel nuclear structures upon DNA damage that cause transcriptional arrest

    SciTech Connect

    Leseleuc, Louis de; Denis, Francois . E-mail: francois.denis@iaf.inrs.ca

    2006-05-15

    The orphan nuclear receptor Nur77 has been implicated in both growth and apoptosis, and its function and activity can be modulated by cellular redistribution. Green fluorescent protein-tagged Nur77 was used to evaluate the role of Nur77 intracellular redistribution in response to genotoxic stress. Selected DNA damaging agents and transcription inhibition lead to rapid redistribution of Nur77 into nuclear structures distinct from conventional nuclear bodies. These nuclear bodies formed transiently were tightly bound to the nuclear matrix and conditions that lead to their appearance were associated with Nur77 transcriptional inhibition. The formation of Nur77 nuclear bodies might be involved in programmed cell death modulation upon exposure to DNA damaging agents that inhibit transcription by sequestrating this proapoptotic factor in dense nuclear structures.

  7. Nur77 deletion impairs muscle growth during developmental myogenesis and muscle regeneration in mice

    PubMed Central

    Cortez-Toledo, Omar; Schnair, Caitlin; Sangngern, Peer; Metzger, Daniel

    2017-01-01

    Muscle atrophy is a prevalent condition in illness and aging. Identifying novel pathways that control muscle mass may lead to therapeutic advancement. We previously identified Nur77 as a transcriptional regulator of glycolysis in skeletal muscle. More recently, we showed that Nur77 expression also controls myofiber size in mice. It was unknown, however, whether Nur77’s regulation of muscle size begins during developmental myogenesis or only in adulthood. To determine the importance of Nur77 throughout muscle growth, we examined myofiber size at E18.5, 3 weeks postnatal age, and in young adult mice. Using the global Nur77-/- mice, we showed that Nur77 deficiency reduced myofiber size as early as E18.5. The reduction in myofiber size became more pronounced by 3 weeks of age. We observed comparable reduction in myofiber size in young myofiber-specific Nur77-knockout mice. These findings suggest that Nur77’s effect on muscle growth is intrinsic to its expression in differentiating myofibers, and not dependent on its expression in myogenic stem cells. To determine the importance of Nur77 expression in muscle accretion in mature mice, we generated an inducible-, muscle-specific, Nur77-deficient mouse model. We demonstrated that tamoxifen-induced deletion of Nur77 in 3-month-old mice reduced myofiber size. This change was accompanied by increased activity of Smad2 and FoxO3, two negative regulators of muscle mass. The role of Nur77 in muscle growth was further elaborated in the cardiotoxin-induced muscle regeneration model. Compared to wildtype mice, regenerated myofibers were smaller in Nur77-/- mice. However, when normalized to saline-injected muscle, the recovery of sarcoplasmic area was comparable between Nur77-/- and wildtype mice. These findings suggest that Nur77 deficiency compromises myofiber growth, but not the regenerative capacity of myogenic progenitor cells. Collectively, the findings presented here demonstrate Nur77 as an important regulator of muscle

  8. Nur77 deletion impairs muscle growth during developmental myogenesis and muscle regeneration in mice.

    PubMed

    Cortez-Toledo, Omar; Schnair, Caitlin; Sangngern, Peer; Metzger, Daniel; Chao, Lily C

    2017-01-01

    Muscle atrophy is a prevalent condition in illness and aging. Identifying novel pathways that control muscle mass may lead to therapeutic advancement. We previously identified Nur77 as a transcriptional regulator of glycolysis in skeletal muscle. More recently, we showed that Nur77 expression also controls myofiber size in mice. It was unknown, however, whether Nur77's regulation of muscle size begins during developmental myogenesis or only in adulthood. To determine the importance of Nur77 throughout muscle growth, we examined myofiber size at E18.5, 3 weeks postnatal age, and in young adult mice. Using the global Nur77-/- mice, we showed that Nur77 deficiency reduced myofiber size as early as E18.5. The reduction in myofiber size became more pronounced by 3 weeks of age. We observed comparable reduction in myofiber size in young myofiber-specific Nur77-knockout mice. These findings suggest that Nur77's effect on muscle growth is intrinsic to its expression in differentiating myofibers, and not dependent on its expression in myogenic stem cells. To determine the importance of Nur77 expression in muscle accretion in mature mice, we generated an inducible-, muscle-specific, Nur77-deficient mouse model. We demonstrated that tamoxifen-induced deletion of Nur77 in 3-month-old mice reduced myofiber size. This change was accompanied by increased activity of Smad2 and FoxO3, two negative regulators of muscle mass. The role of Nur77 in muscle growth was further elaborated in the cardiotoxin-induced muscle regeneration model. Compared to wildtype mice, regenerated myofibers were smaller in Nur77-/- mice. However, when normalized to saline-injected muscle, the recovery of sarcoplasmic area was comparable between Nur77-/- and wildtype mice. These findings suggest that Nur77 deficiency compromises myofiber growth, but not the regenerative capacity of myogenic progenitor cells. Collectively, the findings presented here demonstrate Nur77 as an important regulator of muscle

  9. Nur77 exacerbates PC12 cellular injury in vitro by aggravating mitochondrial impairment and endoplasmic reticulum stress

    PubMed Central

    Gao, Huimin; Chen, Zhaoyu; Fu, Yongmei; Yang, Xiaoyan; Weng, Ruihui; Wang, Rui; Lu, Jianjun; Pan, Mengqiu; Jin, Kunlin; McElroy, Chris; Tang, Beisha; Xia, Ying; Wang, Qing

    2016-01-01

    The nuclear orphan receptor, Nur77 plays important roles in neuroimflammation, apoptosis, and dopaminergic neurodegeneration. We conducted a further mechanistic investigation into the association of Nur77 with cell death. Cytosporone B (Csn-B), an agonist for Nur77, and Nur77 knockdown were adopted in the 6-hydroxydopamine (OHDA)-lesioned PC12 cells to investigate the mechanisms underlying Nur77-mediated injury. The 6-OHDA incubation caused Nur77 translocation from the nucleus to cytosol and Endoplasm reticulum (ER) and induced co-localization of Tom20/Nur77 and Protein Disulfide Isomerase (PDI)/Nur77. Nur77 activation further decreased cell viability, aggravated intracellular LDH release, intracellular Ca2+, ROS levels, apoptosis, ER tress and, mitochondrial transmembrane potential (ΔΨm) decline. In addition, Nur77 activation significantly enhanced the efficiency of autophagy as indicated by an up-regulation of Beclin-1/LC-3 and downregulation of p62, and aggravated mitochondrial dysfunctions and ER stress as shown by increased HSP60/Cytochrome C (Cyt C) and CHOP-ATF3 levels respectively. These changes could be partially reversed by Nur77 knockdown. Moreover, Nur77 activation upregulated PINK1 and downregulated Parkin levels. We conclude that Nur77 exacerbates PC12 cell death at least partially by aggravating the mitochondrial impairment and ER stress and enhancing autophagy. We propose that Nur77 is likely a critical target in the PD therapy. PMID:27679973

  10. Mitochondrial translocation of Nur77 induced by ROS contributed to cardiomyocyte apoptosis in metabolic syndrome

    SciTech Connect

    Xu, Aibin; Liu, Jingyi; Liu, Peilin; Jia, Min; Wang, Han; Tao, Ling

    2014-04-18

    Highlights: • Metabolic syndrome exacerbated MI/R induced injury accompanied by decreased Nur77. • ROS led to Nur77 translocation in metabolic syndrome. • Inhibiting relocation of Nur77 to mitochondria reduced ROS-induced cardiomyocyte injury in metabolic syndrome. - Abstract: Metabolic syndrome is a major risk factor for cardiovascular diseases, and increased cardiomyocyte apoptosis which contributes to cardiac dysfunction after myocardial ischemia/reperfusion (MI/R) injury. Nur77, a nuclear orphan receptor, is involved in such various cellular events as apoptosis, proliferation, and glucose and lipid metabolism in several cell types. Apoptosis is positively correlated with mitochondrial translocation of Nur77 in the cancer cells. However, the roles of Nur77 on cardiac myocytes in patients with metabolic syndrome remain unclear. The objective of this study was to determine whether Nur77 may contribute to cardiac apoptosis in patients with metabolic syndrome after I/R injury, and, if so, to identify the underlying molecular mechanisms responsible. We used leptin-deficient (ob/ob) mice to make metabolic syndrome models. In this report, we observed that, accompanied by the substantial decline in apoptosis inducer Nur77, MI/R induced cardiac dysfunction was manifested as cardiomyopathy and increased ROS. Using the neonatal rat cardiac myocytes cultured in a high-glucose and high-fat medium, we found that excessive H{sub 2}O{sub 2} led to the significant alteration in mitochondrial membrane potential and translocation of Nur77 from the nucleus to the mitochondria. However, inhibition of the relocation of Nur77 to mitochondria via Cyclosporin A reversed the changes in membrane potential mediated by H{sub 2}O{sub 2} and reduced myocardial cell injury. Therefore, these data provide a potential underlying mechanism for cardiac dysfunction in metabolic syndrome and the suppression of Nur77 translocation may provide an effective approach to reduce cardiac injury in the

  11. Nur77 suppresses hepatocellular carcinoma via switching glucose metabolism toward gluconeogenesis through attenuating phosphoenolpyruvate carboxykinase sumoylation

    PubMed Central

    Bian, Xue-li; Chen, Hang-zi; Yang, Peng-bo; Li, Ying-ping; Zhang, Fen-na; Zhang, Jia-yuan; Wang, Wei-jia; Zhao, Wen-xiu; Zhang, Sheng; Chen, Qi-tao; Zheng, Yu; Sun, Xiao-yu; Wang, Xiao-min; Chien, Kun-Yi; Wu, Qiao

    2017-01-01

    Gluconeogenesis, an essential metabolic process for hepatocytes, is downregulated in hepatocellular carcinoma (HCC). Here we show that the nuclear receptor Nur77 is a tumour suppressor for HCC that regulates gluconeogenesis. Low Nur77 expression in clinical HCC samples correlates with poor prognosis, and a Nur77 deficiency in mice promotes HCC development. Nur77 interacts with phosphoenolpyruvate carboxykinase (PEPCK1), the rate-limiting enzyme in gluconeogenesis, to increase gluconeogenesis and suppress glycolysis, resulting in ATP depletion and cell growth arrest. However, PEPCK1 becomes labile after sumoylation and is degraded via ubiquitination, which is augmented by the p300 acetylation of ubiquitin-conjugating enzyme 9 (Ubc9). Although Nur77 attenuates sumoylation and stabilizes PEPCK1 via impairing p300 activity and preventing the Ubc9-PEPCK1 interaction, Nur77 is silenced in HCC samples due to Snail-mediated DNA methylation of the Nur77 promoter. Our study reveals a unique mechanism to suppress HCC by switching from glycolysis to gluconeogenesis through Nur77 antagonism of PEPCK1 degradation. PMID:28240261

  12. Nur77 suppresses hepatocellular carcinoma via switching glucose metabolism toward gluconeogenesis through attenuating phosphoenolpyruvate carboxykinase sumoylation.

    PubMed

    Bian, Xue-Li; Chen, Hang-Zi; Yang, Peng-Bo; Li, Ying-Ping; Zhang, Fen-Na; Zhang, Jia-Yuan; Wang, Wei-Jia; Zhao, Wen-Xiu; Zhang, Sheng; Chen, Qi-Tao; Zheng, Yu; Sun, Xiao-Yu; Wang, Xiao-Min; Chien, Kun-Yi; Wu, Qiao

    2017-02-27

    Gluconeogenesis, an essential metabolic process for hepatocytes, is downregulated in hepatocellular carcinoma (HCC). Here we show that the nuclear receptor Nur77 is a tumour suppressor for HCC that regulates gluconeogenesis. Low Nur77 expression in clinical HCC samples correlates with poor prognosis, and a Nur77 deficiency in mice promotes HCC development. Nur77 interacts with phosphoenolpyruvate carboxykinase (PEPCK1), the rate-limiting enzyme in gluconeogenesis, to increase gluconeogenesis and suppress glycolysis, resulting in ATP depletion and cell growth arrest. However, PEPCK1 becomes labile after sumoylation and is degraded via ubiquitination, which is augmented by the p300 acetylation of ubiquitin-conjugating enzyme 9 (Ubc9). Although Nur77 attenuates sumoylation and stabilizes PEPCK1 via impairing p300 activity and preventing the Ubc9-PEPCK1 interaction, Nur77 is silenced in HCC samples due to Snail-mediated DNA methylation of the Nur77 promoter. Our study reveals a unique mechanism to suppress HCC by switching from glycolysis to gluconeogenesis through Nur77 antagonism of PEPCK1 degradation.

  13. The orphan nuclear receptor Nur77 regulates decidual prolactin expression in human endometrial stromal cells

    SciTech Connect

    Jiang, Yue; Hu, Yali; Zhao, Jing; Zhen, Xin; Yan, Guijun; Sun, Haixiang

    2011-01-14

    Research highlights: {yields} Decidually produced PRL plays a key role during pregnancy. {yields} Overexpression of Nur77 increased PRL mRNA expression and enhanced decidual PRL promoter activity. {yields} Knockdown of Nur77 decreased decidual PRL secretion induced by 8-Br-cAMP and MPA. {yields} Nur77 is a novel transcription factor that plays an active role in decidual prolactin expression. -- Abstract: Prolactin (PRL) is synthesized and released by several extrapituitary tissues, including decidualized stromal cells. Despite the important role of decidual PRL during pregnancy, little is understood about the factors involved in the proper regulation of decidual PRL expression. Here we present evidence that the transcription factor Nur77 plays an active role in decidual prolactin expression in human endometrial stromal cells (hESCs). Nur77 mRNA expression in hESCs was significantly increased after decidualization stimulated by 8-Br-cAMP and medroxyprogesterone acetate (MPA). Adenovirus-mediated overexpression of Nur77 in hESCs markedly increased PRL mRNA expression and enhanced decidual PRL promoter (dPRL/-332Luc) activity in a concentration-dependent manner. Furthermore, knockdown of Nur77 in hESCs significantly decreased decidual PRL promoter activation and substantially attenuated PRL mRNA expression and PRL secretion (P < 0.01) induced by 8-Br-cAMP and MPA. These results demonstrate that Nur77 is a novel transcription factor that contributes significantly to the regulation of prolactin gene expression in human endometrial stromal cells.

  14. Orphan nuclear receptor Nur77 participates in human apolipoprotein A5 gene expression

    SciTech Connect

    Song, Kwang-Hoon

    2010-01-29

    The orphan nuclear receptor Nur77 (NR4A1) has been reported to play a crucial role in the modulation of diverse metabolic processes in liver. Here, we reported the identification of human apolipoprotein A5 (ApoA5), which implicated in lowering plasma triglyceride levels, as a novel target gene of Nur77. Nur77 induced the human ApoA5 promoter activity. Using 5'-deletion and mutagenesis of human ApoA5 promoter analysis and chromatin immunoprecipitation assays, it was shown that Nur77 directly regulated human ApoA5 gene expression by binding to a Nur77 response element (AAAGGTCA) located in the proximal human ApoA5 promoter region. In addition, we demonstrated that blocking of Nur77 transcriptional activity via overexpression of dominant negative Nur77 suppressed human ApoA5 promoter activity and mRNA expression in human hepatoma cells, HepG2. Taken together, our results demonstrated that Nur77 is a novel regulator of human ApoA5 gene expression and provide a new insight into the role of this orphan nuclear receptor in lipoprotein metabolism and triglyceride homeostasis.

  15. Biochemical and Functional Characterization of the NurA-HerA Complex from Deinococcus radiodurans

    PubMed Central

    Cheng, Kaiying; Chen, Xuanyi; Xu, Guangzhi; Wang, Liangyan; Xu, Hong; Yang, Su

    2015-01-01

    ABSTRACT In archaea, the NurA nuclease and HerA ATPase/helicase, together with the Mre11-Rad50 complex, function in 3′ single-stranded DNA (ssDNA) end processing during homologous recombination (HR). However, bacterial homologs of NurA and HerA have not been characterized. From Deinococcus radiodurans, we identified the manganese-dependent 5′-to-3′ ssDNA/double-stranded DNA (dsDNA) exonuclease/endonuclease NurA (DrNurA) and the ATPase HerA (DrHerA). These two proteins stimulated each other's activity through direct protein-protein interactions. The N-terminal HAS domain of DrHerA was the key domain for this interaction. Several critical residues of DrNurA and DrHerA were verified by site-directed mutational analysis. Temperature-dependent activity assays confirmed that the two proteins had mesophilic features, with optimum activity temperatures 10°C to 15°C higher than their optimum growth temperatures. Knocking out either nurA or herA affected cell proliferation by shortening the growth phase, especially for growth at a high temperature (37°C). In addition, both mutant strains displayed almost 10-fold-reduced intermolecular recombination efficiency, indicating that DrNurA and DrHerA might be involved in homologous recombination in vivo. However, single- and double-gene deletions did not show significantly decreased radioresistance. Our results confirmed that the biochemical activities of bacterial NurA and HerA proteins were conserved with archaea. Our phenotypical results suggested that these proteins might have different functions in bacteria. IMPORTANCE Deinococcus radiodurans NurA (DrNurA) was identified as a manganese-dependent 5′-to-3′ ssDNA/dsDNA exonuclease/endonuclease, and Deinococcus radiodurans HerA (DrHerA) was identified as an ATPase. Physical interactions between DrNurA and DrHerA explained mutual stimulation of their activities. The N-terminal HAS domain on DrHerA was identified as the interaction domain. Several essential functional

  16. Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity

    SciTech Connect

    Pols, Thijs W.H.; Ottenhoff, Roelof; Vos, Mariska; Levels, Johannes H.M.; Quax, Paul H.A.; Meijers, Joost C.M.; Pannekoek, Hans; Groen, Albert K.; Vries, Carlie J.M. de

    2008-02-22

    NR4A nuclear receptors are induced in the liver upon fasting and regulate hepatic gluconeogenesis. Here, we studied the role of nuclear receptor Nur77 (NR4A1) in hepatic lipid metabolism. We generated mice expressing hepatic Nur77 using adenoviral vectors, and demonstrate that these mice exhibit a modulation of the plasma lipid profile and a reduction in hepatic triglyceride. Expression analysis of >25 key genes involved in lipid metabolism revealed that Nur77 inhibits SREBP1c expression. This results in decreased SREBP1c activity as is illustrated by reduced expression of its target genes stearoyl-coA desaturase-1, mitochondrial glycerol-3-phosphate acyltransferase, fatty acid synthase and the LDL receptor, and provides a mechanism for the physiological changes observed in response to Nur77. Expression of LXR target genes Abcg5 and Abcg8 is reduced by Nur77, and may suggest involvement of LXR in the inhibitory action of Nur77 on SREBP1c expression. Taken together, our study demonstrates that Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity.

  17. Regulation of Nur77 gene expression by prostanoids in cementoblastic cells.

    PubMed

    Moldovan, Sanda M; Nervina, Jeanne M; Tetradis, Sotirios; Camargo, Paulo M

    2009-05-01

    The inflammatory cytokine interleukin-1 (IL-1) decreases mineralisation by immortalized mouse-derived cementoblastic cells (OC-CM cells), whilst various prostanoids, including fluprostenol (flup) increase it. Subtraction hybridisation conducted on flup minus IL-1-treated OC-CM cells revealed that one of the primary response genes preferentially induced by flup is the transcription factor Nur77. The objective of this study was to examine the signal transduction cascades regulating prostanoid induction of Nur77 gene expression in OC-CM cells. Confluent OC-CM cells were treated with prostaglandin E(2) (PGE(2)), prostaglandin F(2alpha) (PGF(2alpha)), specific activators of the various EP prostanoid receptors and of the FP prostanoid receptor, and direct activators/inhibitors of the cyclic AMP-protein kinase A (PKA), protein kinase C (PKC) and intracellular calcium pathways. Nur77 gene expression was examined by mRNA extraction and Northern blot analysis. PGE(2) and PGF(2alpha) treatment of OC-CM cells significantly increased Nur77 mRNA expression in a time- and dose-dependent fashion. Both the EP1 prostanoid receptor-specific activator 16,16-dimethyl-PGE(2) and the FP prostanoid receptor-specific activator flup significantly increased Nur77 gene expression by OC-CM cells as compared to vehicle-treated controls. Increase in Nur77 gene expression was also observed when direct activators of the PKA, PKC and intracellular calcium pathways were used to treat OC-CM cells. Direct inhibition of the PKA, PKC and intracellular calcium pathways abrogated Nur77 gene expression induced by OC-CM cell treatment with PGE(2) and PGF(2alpha). Nur77 is a primary gene expressed by OC-CM cells and its induction appears to be mediated by the PKA, PKC and intracellular calcium pathways. Nur77 may affect expression of downstream target genes in OC-CM cells and partially regulate cementoblast cell function.

  18. Induction of Nur77 by hyperoside inhibits vascular smooth muscle cell proliferation and neointimal formation.

    PubMed

    Huo, Yan; Yi, Bing; Chen, Ming; Wang, Nadan; Chen, Pengguo; Guo, Cheng; Sun, Jianxin

    2014-12-15

    Nur77 is an orphan nuclear receptor that belongs to the nuclear receptor 4A (NR4A) subfamily, which has been implicated in a variety of biological events, such as cell apoptosis, proliferation, inflammation, and metabolism. Activation of Nur77 has recently been shown to be beneficial for the treatment of cardiovascular and metabolic diseases. The purpose of this study is to identify novel natural Nur77 activators and investigate their roles in preventing vascular diseases. By measuring Nur77 expression using quantitative RT-PCR, we screened active ingredients extracted from Chinese herb medicines with beneficial cardiovascular effects. Hyperoside (quercetin 3-D-galactoside) was identified as one of the potent activators for inducing Nur77 expression and activating its transcriptional activity in vascular smooth muscle cells (VSMCs). We demonstrated that hyperoside, in a time and dose dependent manner, markedly increased the expression of Nur77 in rat VSMCs, with an EC50 of ∼0.83 μM. Mechanistically, we found that hyperoside significantly increased the phosphorylation of ERK1/2 MAP kinase and its downstream target cAMP response element-binding protein (CREB), both of which contributed to the hyperoside-induced Nur77 expression in rat VSMCs. Moreover, through activation of Nur77 receptor, hyperoside markedly inhibited both vascular smooth muscle cell proliferation in vitro and the carotid artery ligation-induced neointimal formation in vivo. These findings demonstrate that hyperoside is a potent natural activator of Nur77 receptor, which can be potentially used for prevention and treatment of occlusive vascular diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Magnesium Sulfate and Betamethasone Reduce NUR77 Expression in a Preterm Labor Mouse Model

    DTIC Science & Technology

    2016-06-29

    these medications prevent neurologic injury in the pretem1 infant. 1S. SUBJECT TERMS Nur77, neuroinflammation, pregnancy 16. SECURITY...former includes tocolysis, progesterone therapy, and cerclage. Historically, the latter has consisted almost exclusively of corticosteroid therapy

  20. [Analysis of Lop Nur "Ear" features in remote sensing image and its environmental meaning].

    PubMed

    Cai, Ai-Min; Shao, Yun; Gong, Hua-Ze; Wang, Guo-Jun; Xie, Chou

    2011-06-01

    There is a great significance of revealing the characteristics of regional environment evolution and global change to the research on arid Lop Nur areas. By the "Ear" features of Lop Nur in remote sensing image, the spectrum, soil and surface parameters were analyzed. The differences in total salt content in soil and the surface structure bring are cause directly for the "Ear" features in remote sensing image; The results of the analysis of spectrum, total salt content and particle size are in good agreement. "Ear" features recorded the process of environmental change. The process implys that Lop Nur dried up gradually under the impact of global change. The adjustment during the process of drying up let Lop Nur experience two relatively humid climates, with the previous a little longer, the later very short.

  1. The transcription factors Nur77 and retinoid X receptors participate in amphetamine-induced locomotor activities.

    PubMed

    Bourhis, Emmanuelle; Maheux, Jérôme; Paquet, Brigitte; Kagechika, Hiroyuki; Shudo, Koichi; Rompré, Pierre-Paul; Rouillard, Claude; Lévesque, Daniel

    2009-03-01

    The major substrate underlying amphetamine (AMPH)-induced locomotor activity is associated with dopamine forebrain circuits. Brain regions associated with AMPH-induced locomotor activity express high levels of retinoid receptors. However, the role of these transcription factors in dopamine-mediated effects remains poorly understood. Two nuclear receptor families, the retinoic acid receptors (RAR) and the retinoid X receptors (RXR), transduce retinoic acid signal. RARs are specifically involved in retinoid signaling, whereas RXRs also participate in other signaling pathways as partners for other nuclear receptors such as Nur77, an orphan member of the nuclear receptor family expresses in dopamine system. To explore the role of retinoid receptors and Nur77 in AMPH-induced locomotor activity, we administered selective retinoid receptor drugs in combination with AMPH in adult wild-type and Nur77-deficient mice. At a low dose, AMPH similarly increased ambulatory activity in wild-type and Nur77-deficient mice, while it did not alter non-ambulatory activity. At a high dose, AMPH did not alter ambulatory activity anymore, while non-ambulatory activity strongly increased in wild-type mice. Nur77-deficient mice still displayed a higher ambulatory activity with no change in non-ambulatory activity. HX531, a synthetic RXR antagonist, blocks AMPH-induced ambulatory activity, whereas RAR drugs tested remained without effect. Interestingly, the effect of HX531 was abolished in Nur77-deficient mice, suggesting that this orphan nuclear receptor is essential for the action of the RXR drug. This study shows that RXR and Nur77 participate in AMPH-induced locomotor activity and prompts for further investigations on the role of Nur77 and RXR in addiction and reward-related behaviors.

  2. Molecular architecture of the HerA-NurA DNA double-strand break resection complex.

    PubMed

    Byrne, Robert Thomas; Schuller, Jan Michael; Unverdorben, Pia; Förster, Friedrich; Hopfner, Karl-Peter

    2014-12-20

    DNA double-strand breaks can be repaired by homologous recombination, during which the DNA ends are long-range resected by helicase-nuclease systems to generate 3' single strand tails. In archaea, this requires the Mre11-Rad50 complex and the ATP-dependent helicase-nuclease complex HerA-NurA. We report the cryo-EM structure of Sulfolobus solfataricus HerA-NurA at 7.4Å resolution and present the pseudo-atomic model of the complex. HerA forms an ASCE hexamer that tightly interacts with a NurA dimer, with each NurA protomer binding three adjacent HerA HAS domains. Entry to NurA's nuclease active sites requires dsDNA to pass through a 23Å wide channel in the HerA hexamer. The structure suggests that HerA is a dsDNA translocase that feeds DNA into the NurA nuclease sites.

  3. Inhibition of Nur77/Nurr1 leads to inefficient clonal deletion of self- reactive T cells

    PubMed Central

    1996-01-01

    The Nur77/Nurr1 family of DNA binding proteins has been reported to be required for the signal transduction of CD3/T cell receptor (TCR)- mediated apoptosis in T cell hybridomas. To determine the role of this family of DNA-binding proteins in thymic clonal deletion, transgenic (Tg) mice bearing a dominant negative mutation were produced. The transgene consisted of a truncated Nur77 (deltaNur77) gene encoding the DNA-binding domain of Nur77 ligated to a TCR-beta enhancer resulting in early expression in thymocytes. Apoptosis of CD4+CD8+ thymocytes mediated by CD3/TCR signaling was greatly inhibited in the deltaNur77 Tg mice, compared with non-Tg littermates, after treatment with anti- CD3 or anti-TCR antibody in vivo and in vitro. Clonal deletion of self- reactive T cells was investigated in deltaNur77-Db/HY TCR-alpha/beta double Tg mice. There was a five-fold increase in the total number of thymocytes expressing self-reactive Db/HY TCR-alpha/beta in the deltaNur77-TCR-alpha/beta double Tg male mice. Deficient clonal deletion of self-reactive thymocytes was demonstrated by a 10-fold increase in the CD4+CD8+ thymocytes that expressed Tg TCR-alpha/beta. There was an eightfold increase in the CD8+, Db/HY TCR-alpha/beta T cells in the lymph nodes (LN) of delta Nur77-Db/HY TCR-alpha/beta double Tg compared with Db/HY TCR-alpha/beta Tg male mice. In spite of defective clonal deletion, the T cells expressing the Tg TCR were functionally anergic. In vivo analysis revealed increased activation and apoptosis of T cells associated with increased expression of Fas and Fas ligand in LN of deltaNur77-Db/HY TCR-alpha/beta double male mice. These results indicate that inhibition of Nur77/Nurr1 DNA binding in T cells leads to inefficient thymic clonal deletion, but T cell tolerance is maintained by Fas-dependent clonal deletion in LN and spleen. PMID:8666944

  4. Nur77 deficiency in mice accelerates tumor invasion and metastasis by facilitating TNFα secretion and lowering CSF-1R expression

    PubMed Central

    Gao, Shang-Shang; He, Xiao-Shun; Li, Jiang-Nan; Yang, Tian-Yu; Zhang, Shen; Gan, Wen-Juan; Li, Jian-Ming

    2017-01-01

    Nur77, an orphan member of the nuclear receptor superfamily, plays critical roles in inflammation and immunity. However, the role of Nur77 in tumor microenvironment remains elusive. Results showed that deletion of Nur77 strikingly enhanced tumor metastasis compared to WT mice. Additionally, compared to the conditioned media derived from Nur77+/+ peritoneal macrophages (CM1), the conditioned media derived from Nur77-/- peritoneal macrophages (CM2) significantly promoted the EMT of cancer cells, and greatly enhanced the migratory and invasive abilities of cancer cells. Moreover, studies using TNF-α blocking antibody demonstrated that pro-inflammatory cytokine TNF-α was indispensable in supporting CM2-induced EMT to drive cancer cells migration and invasion. Furthermore, we found that Nur77 promoted the expression of CSF-1R, a novel downstream target gene of Nur77, and subsequently enhanced the migration of inflammatory cells. Notably, infiltration of inflammatory cells in the tumors of Nur77-/- mice was markedly abrogated compared to Nur77+/+ mice. Collectively, these results revealed that host Nur77 expression was pivotal in antitumor immune response, and in inhibiting tumor metastasis. PMID:28170411

  5. Deficiency of Nuclear Receptor Nur77 Aggravates Mouse Experimental Colitis by Increased NFκB Activity in Macrophages

    PubMed Central

    Hamers, Anouk A. J.; van Dam, Laura; Teixeira Duarte, José M.; Vos, Mariska; Marinković, Goran; van Tiel, Claudia M.; Meijer, Sybren L.; van Stalborch, Anne-Marieke; Huveneers, Stephan; te Velde, Anje A.

    2015-01-01

    Nuclear receptor Nur77, also referred to as NR4A1 or TR3, plays an important role in innate and adaptive immunity. Nur77 is crucial in regulating the T helper 1/regulatory T-cell balance, is expressed in macrophages and drives M2 macrophage polarization. In this study we aimed to define the function of Nur77 in inflammatory bowel disease. In wild-type and Nur77-/- mice, colitis development was studied in dextran sodium sulphate (DSS)- and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced models. To understand the underlying mechanism, Nur77 was overexpressed in macrophages and gut epithelial cells. Nur77 protein is expressed in colon tissues from Crohn’s disease and Ulcerative colitis patients and colons from colitic mice in inflammatory cells and epithelium. In both mouse colitis models inflammation was increased in Nur77-/- mice. A higher neutrophil influx and enhanced IL-6, MCP-1 and KC production was observed in Nur77-deficient colons after DSS-treatment. TNBS-induced influx of T-cells and inflammatory monocytes into the colon was higher in Nur77-/- mice, along with increased expression of MCP-1, TNFα and IL-6, and decreased Foxp3 RNA expression, compared to wild-type mice. Overexpression of Nur77 in lipopolysaccharide activated RAW macrophages resulted in up-regulated IL-10 and downregulated TNFα, MIF-1 and MCP-1 mRNA expression through NFκB repression. Nur77 also strongly decreased expression of MCP-1, CXCL1, IL-8, MIP-1α and TNFα in gut epithelial Caco-2 cells. Nur77 overexpression suppresses the inflammatory status of both macrophages and gut epithelial cells and together with the in vivo mouse data this supports that Nur77 has a protective function in experimental colitis. These findings may have implications for development of novel targeted treatment strategies regarding inflammatory bowel disease and other inflammatory diseases. PMID:26241646

  6. Nur77 is differentially modified in PC12 cells upon membrane depolarization and growth factor treatment.

    PubMed Central

    Hazel, T G; Misra, R; Davis, I J; Greenberg, M E; Lau, L F

    1991-01-01

    The rat pheochromocytoma cell line PC12 can be induced by growth factors to undergo proliferation and neuronal differentiation. These cells also have excitable membranes that can be depolarized by neurotransmitters or elevated levels of extracellular KCl. Treatment of PC12 cells with growth factors or membrane-depolarizing agents rapidly activates the expression of specific genes whose products are thought to mediate the subsequent biological responses. One such gene, nur77, is a member of the steroid and thyroid hormone receptor gene superfamily. We have identified the Nur77 protein and shown that it is synthesized rapidly and transiently in PC12 cells following stimulation, has a short half-life of 30 to 40 min, and is located in both the nucleus and the cytoplasm. Nur77 is posttranslationally modified, primarily by phosphorylation on serine residues. Phosphopeptide analysis reveals that Nur77 is modified differently upon membrane depolarization than after treatment with growth factors. We hypothesize that the activity of Nur77 is regulated by both differential gene expression and posttranslational modification and that these modes of regulation contribute to distinct downstream responses specific to membrane depolarization and growth factor treatment. Images PMID:1645447

  7. Apoptosis of nur77/N10-transgenic thymocytes involves the Fas/Fas ligand pathway.

    PubMed Central

    Weih, F; Ryseck, R P; Chen, L; Bravo, R

    1996-01-01

    The orphan nuclear receptor Nur77/N10 has recently been demonstrated to be involved in apoptosis of T cell hybridomas. We report here that chronic expression of Nur77/N10 in thymocytes of transgenic mice results in a dramatic reduction of CD4+CD8+ double-positive as well as CD4+CD8- and CD4-CD8+ single-positive cell populations due to an early onset of apoptosis. CD4-CD8- double-negative and CD25+ precursor cells, however, are unaffected. Moreover, nur77/N10-transgenic thymocytes show increased expression of Fas ligand (FasL), while the levels of the Fas receptor (Fas) are not increased. The mouse spontaneous mutant gld (generalized lymphoproliferative disease) carries a point mutation in the extracellular domain of the FasL gene that abolishes the ability of FasL to bind to Fas. Thymuses from nur77/N10-transgenic mice on a gld/gld background have increased cellularity and an almost normal profile of thymocyte subpopulations. Our results demonstrate that one pathway of apoptosis triggered by Nur77/N10 in double-positive thymocytes occurs through the upregulation of FasL expression resulting in increased signaling through Fas. Images Fig. 1 Fig. 2 Fig. 4 PMID:8643610

  8. The Orphan Nuclear Receptor Nur77 Is a Determinant of Myofiber Size and Muscle Mass in Mice

    PubMed Central

    Tontonoz, Peter; Cortez-Toledo, Omar; Wroblewski, Kevin; Hong, Cynthia; Lim, Laura; Carranza, Rogelio; Conneely, Orla; Metzger, Daniel

    2015-01-01

    We previously showed that the orphan nuclear receptor Nur77 (Nr4a1) plays an important role in the regulation of glucose homeostasis and oxidative metabolism in skeletal muscle. Here, we show using both gain- and loss-of-function models that Nur77 is also a regulator of muscle growth in mice. Transgenic expression of Nur77 in skeletal muscle in mice led to increases in myofiber size. Conversely, mice with global or muscle-specific deficiency in Nur77 exhibited reduced muscle mass and myofiber size. In contrast to Nur77 deficiency, deletion of the highly related nuclear receptor NOR1 (Nr4a3) had minimal effect on muscle mass and myofiber size. We further show that Nur77 mediates its effects on muscle size by orchestrating transcriptional programs that favor muscle growth, including the induction of insulin-like growth factor 1 (IGF1), as well as concomitant downregulation of growth-inhibitory genes, including myostatin, Fbxo32 (MAFbx), and Trim63 (MuRF1). Nur77-mediated increase in IGF1 led to activation of the Akt-mTOR-S6K cascade and the inhibition of FoxO3a activity. The dependence of Nur77 on IGF1 was recapitulated in primary myoblasts, establishing this as a cell-autonomous effect. Collectively, our findings identify Nur77 as a novel regulator of myofiber size and a potential transcriptional link between cellular metabolism and muscle growth. PMID:25605333

  9. The orphan nuclear receptor Nur77 is a determinant of myofiber size and muscle mass in mice.

    PubMed

    Tontonoz, Peter; Cortez-Toledo, Omar; Wroblewski, Kevin; Hong, Cynthia; Lim, Laura; Carranza, Rogelio; Conneely, Orla; Metzger, Daniel; Chao, Lily C

    2015-04-01

    We previously showed that the orphan nuclear receptor Nur77 (Nr4a1) plays an important role in the regulation of glucose homeostasis and oxidative metabolism in skeletal muscle. Here, we show using both gain- and loss-of-function models that Nur77 is also a regulator of muscle growth in mice. Transgenic expression of Nur77 in skeletal muscle in mice led to increases in myofiber size. Conversely, mice with global or muscle-specific deficiency in Nur77 exhibited reduced muscle mass and myofiber size. In contrast to Nur77 deficiency, deletion of the highly related nuclear receptor NOR1 (Nr4a3) had minimal effect on muscle mass and myofiber size. We further show that Nur77 mediates its effects on muscle size by orchestrating transcriptional programs that favor muscle growth, including the induction of insulin-like growth factor 1 (IGF1), as well as concomitant downregulation of growth-inhibitory genes, including myostatin, Fbxo32 (MAFbx), and Trim63 (MuRF1). Nur77-mediated increase in IGF1 led to activation of the Akt-mTOR-S6K cascade and the inhibition of FoxO3a activity. The dependence of Nur77 on IGF1 was recapitulated in primary myoblasts, establishing this as a cell-autonomous effect. Collectively, our findings identify Nur77 as a novel regulator of myofiber size and a potential transcriptional link between cellular metabolism and muscle growth.

  10. [Detection of trace elements in the sediment of Lop Nur samples by ICP-MS].

    PubMed

    Hu, Xin; An, Deng-Di; Dlinur, Mlik; Li, Jiang; Liu, Yu-Xiang; Ji, Heng-Ying; Zhu, Yan-Lei

    2012-06-01

    Twenty eight trace elements in the sediment of Lop Nur in different latitude and longitude were tested by ICP-MS. The results showed that the metal contents in the soil profile followed a growing trend from the surface to the bottom. And the essential element P for living body in each sample was very low, and was the lowest on the surface, while was matched in the other four layers. The results will help to understand the ecosystem evolution of Lop Nur drying up after the sediment deposition.

  11. Nur77 inhibits oxLDL induced apoptosis of macrophages via the p38 MAPK signaling pathway

    SciTech Connect

    Shao, Qin; Han, Fei; Peng, Shi; He, Ben

    2016-03-18

    The interaction between macrophages and oxLDL plays a crucial role in the initiation and progression of atherosclerosis. As a key initiator in a number of plaque promoting processes, oxLDL induces variable effects such as cell apoptosis or proliferation. Orphan nuclear receptor Nur77 is potently induced in macrophages by diverse stimuli, suggesting that it is of importance in vascular inflammation resulting in atherosclerosis, but whether Nur77 induction is detrimental or protective is unclear. In our study, we explore the role of Nur77 in the regulation of oxLDL-induced macrophage apoptosis and the signaling pathways that are involved. We found that oxLDL induced Nur77 expression in a dose and time dependent fashion, and cell viability was decreased in parallel. To determine whether Nur77 induction contributes to the loss of cell viability or is a protective mechanism, the effect of Nur77 overexpression was examined. Importantly, Nur77 overexpression inhibited the oxLDL-induced decrease of cell viability, inhibited the production of apoptotic bodies and restored DNA synthesis following oxLDL exposure. Furthermore, we found that Nur77 induction is mediated through the p38 MAPK signaling pathway. After pretreatment with SB203580, cell viability was decreased, the expression of CyclinA2 and PCNA was attenuated and the percentage of cell apoptosis was enhanced. Likewise, Nur77 overexpression increased the expression of the cell cycle genes PCNA and p21, and attenuated the increase in caspase-3. On the other hand, knockdown of Nur77 expression by specific siRNA resulted in the increased expression of caspase 3. The results demonstrate that Nur77 is induced by oxLDL via the p38 MAPK signaling pathway, which is involved in the regulation of cell survival. Nur77 enhanced cell survival via suppressing apoptosis, without affecting cell proliferation of activated macrophages, which may be beneficial in patients with atherosclerosis. - Highlights: • oxLDL could induce Nur77

  12. Honokiol sensitizes breast cancer cells to TNF‐α induction of apoptosis by inhibiting Nur77 expression

    PubMed Central

    Zhang, Xindao; Alitongbieke, Gulimiran; Shi, Xinlei; Meng, MinJun; Xu, Yiming; Ren, Anshi; Wang, Jing; Cai, Lijun; Zhou, Yunxia; Xu, Yang; Su, Ying; Liu, Jie; Zeng, Zhiping; Wang, Guanghui; Zhou, Hu; Chen, Quan Cheng; Zhang, Xiao‐kun

    2016-01-01

    Background and Purpose The orphan nuclear receptor Nur77 is implicated in the survival and apoptosis of cancer cells. The purpose of this study was to determine whether and how Nur77 serves to mediate the effect of the inflammatory cytokine TNF‐α in cancer cells and to identify and characterize new agents targeting Nur77 for cancer therapy. Experimental Approach The effects of TNF‐α on the expression and function of Nur77 were studied using in vitro and in vivo models. Nur77 expression was evaluated in tumour tissues from breast cancer patients. The anticancer effects of honokiol and its mechanism of action were assessed by in vitro, cell‐based and animal studies. Key Results TNF‐α rapidly and potently induced the expression of Nur77 in breast cancer cells through activation of IκB kinase and JNK. Knocking down Nur77 resulted in TNF‐α‐dependent apoptosis, while ectopic Nur77 expression in MCF‐7 cells promoted their growth in animals. Levels of Nur77 were higher in tumour tissues than the corresponding tissues surrounding the tumour in about 50% breast cancer patients studied. Our in vitro and animal studies also identified honokiol as an effective sensitizer of TNF‐α‐induced apoptosis by inhibiting TNF‐α‐induced Nur77 mRNA expression, which could be attributed to its interference of TNFR1's interaction with receptor‐interacting protein 1 (RIPK1). Conclusions and Implications TNF‐α‐induced Nur77 serves as a survival factor to attenuate the death effect of TNF‐α in cancer cells. With its proven human safety profile, honokiol represents a promising agent that warrants further clinical development. PMID:26505879

  13. Honokiol sensitizes breast cancer cells to TNF-α induction of apoptosis by inhibiting Nur77 expression.

    PubMed

    Xie, Lei; Jiang, Fuquan; Zhang, Xindao; Alitongbieke, Gulimiran; Shi, Xinlei; Meng, MinJun; Xu, Yiming; Ren, Anshi; Wang, Jing; Cai, Lijun; Zhou, Yunxia; Xu, Yang; Su, Ying; Liu, Jie; Zeng, Zhiping; Wang, Guanghui; Zhou, Hu; Chen, Quan Cheng; Zhang, Xiao-Kun

    2016-01-01

    The orphan nuclear receptor Nur77 is implicated in the survival and apoptosis of cancer cells. The purpose of this study was to determine whether and how Nur77 serves to mediate the effect of the inflammatory cytokine TNF-α in cancer cells and to identify and characterize new agents targeting Nur77 for cancer therapy. The effects of TNF-α on the expression and function of Nur77 were studied using in vitro and in vivo models. Nur77 expression was evaluated in tumour tissues from breast cancer patients. The anticancer effects of honokiol and its mechanism of action were assessed by in vitro, cell-based and animal studies. TNF-α rapidly and potently induced the expression of Nur77 in breast cancer cells through activation of IκB kinase and JNK. Knocking down Nur77 resulted in TNF-α-dependent apoptosis, while ectopic Nur77 expression in MCF-7 cells promoted their growth in animals. Levels of Nur77 were higher in tumour tissues than the corresponding tissues surrounding the tumour in about 50% breast cancer patients studied. Our in vitro and animal studies also identified honokiol as an effective sensitizer of TNF-α-induced apoptosis by inhibiting TNF-α-induced Nur77 mRNA expression, which could be attributed to its interference of TNFR1's interaction with receptor-interacting protein 1 (RIPK1). TNF-α-induced Nur77 serves as a survival factor to attenuate the death effect of TNF-α in cancer cells. With its proven human safety profile, honokiol represents a promising agent that warrants further clinical development. © 2015 The British Pharmacological Society.

  14. Induction and intracellular localization of Nur77 dictate fenretinide-induced apoptosis of human liver cancer cells

    PubMed Central

    Yang, Hui; Bushue, Nathan; Bu, Pengli; Wan, Yu-Jui Yvonne

    2009-01-01

    Fenretinide, a synthetic retinoid, is known to induce apoptosis in various cancer cells. However, the mechanism by which fenretinide induces apoptosis remains unclear. The current study examines the mechanisms of fenretinide-induced apoptosis in human hepatoma cells. The induction of Nur77 and the cytoplasmic distribution of Nur77 induced by fenretinide were positively correlated with the apoptotic effect of fenretinide in HCC cells. The sensitivity of Huh-7 cells was related to Nur77 translocation and targeting mitochondria, whereas the mechanism of resistance for HepG2 cells seemed due to Nur77 accumulating in the nucleus. The intracellular location of Nur77 was also associated with the differential capability of fenretinide-induced ROS generation in these two cell lines. In addition, the knockdown of Nur77 expression by siRNA greatly reduced fenretinide-induced apoptosis and cleaved caspase3 in Huh7 cells. Therefore, our findings demonstrate that fenretinide-induced apoptosis of HCC cells is Nur77 dependent and that the intracellular localization of Nur77 dictates the sensitivity of the HCC cells to fenretinide-induced apoptosis. PMID:19912993

  15. Induction and intracellular localization of Nur77 dictate fenretinide-induced apoptosis of human liver cancer cells.

    PubMed

    Yang, Hui; Bushue, Nathan; Bu, Pengli; Wan, Yu-Jui Yvonne

    2010-04-01

    Fenretinide, a synthetic retinoid, is known to induce apoptosis in various cancer cells. However, the mechanism by which fenretinide induces apoptosis remains unclear. The current study examines the mechanisms of fenretinide-induced apoptosis in human hepatoma cells. The induction of Nur77 and the cytoplasmic distribution of Nur77 induced by fenretinide were positively correlated with the apoptotic effect of fenretinide in HCC cells. The sensitivity of Huh-7 cells was related to Nur77 translocation and targeting mitochondria, whereas the mechanism of resistance for HepG2 cells seemed due to Nur77 accumulating in the nucleus. The intracellular location of Nur77 was also associated with the differential capability of fenretinide-induced ROS generation in these two cell lines. In addition, the knockdown of Nur77 expression by siRNA greatly reduced fenretinide-induced apoptosis and cleaved caspase 3 in Huh-7 cells. Therefore, our findings demonstrate that fenretinide-induced apoptosis of HCC cells is Nur77 dependent and that the intracellular localization of Nur77 dictates the sensitivity of the HCC cells to fenretinide-induced apoptosis. Published by Elsevier Inc.

  16. Analysis of the formation of the Lop Nur Ear feature using multisource satellite imagery

    NASA Astrophysics Data System (ADS)

    Gao, Zhihong; Gong, Huaze; Shao, Yun; Wang, Longfei

    2014-01-01

    Lop Nur, as the center of China and Eurasia, has a special position in geoscience research. The objective of this paper is to give a comprehensive and reasonable explanation of how the unique Lop Nur Ear feature formed. Because of the severe natural environment, the extensive area, and the difficult field work conditions, remote sensing data are highly suitable for the study of the Lop Nur lake basin. Three types of multisource remote sensing data are applied in this study. Combined with field investigations and laboratory measurements, the causes of the "Ear" feature are explored from different points of view. The results indicate that surface roughness is the most direct cause, while the salinity and depth of the subsurface dry medium layer are the root causes, and topography is an important environmental factor for the formation of the Lop Nur Ear feature. The results of this study help to solve a geological mystery and also provide a new insight into climate change and the demise of ancient civilizations.

  17. [Biodiversity and functional enzymes of cultured halophilic archaeon in Lop Nur region].

    PubMed

    Liu, Bingbing; Tang, Shukun; Ming, Hong; He, Songtao; Nie, Guoxing; Guan, Tongwei; Zhang, Lili; Li, Wenjun

    2011-09-01

    In order to explore the diversity of cultured halophilic archaeon from hypersaline environments in Lop Nur region and their potential application. Total 13 soil samples were collected from Lop Nur regions. Halophilic archaea strains were isolated and identified by 16S rRNA gene sequence analysis. In addition, 17 strains were selected based on different branches in pylogenetic tree, and their salt concentration tolerance and amylase, protease, esterase activities were further detected by conventional methods. The 16S rRNA gene sequences of 56 selected strains were determined, and the phylogenetic analysis was carried out. These strains were classified into 10 known genera and 5 new potential genera, and the Shannon index was 1.820. The range of salt concentration tolerance of most strains was 10% - 35% (optimum at 20% - 25%). Amylase positive rate was 70.6%, protease positive rate was 35.3% and esterase positive rate was 82.4%. Diverse halophilic archaeon were discovered in Lop Nur regions. The isolation methods that we used were successful for isolating halophilic archaeon from these areas, which provided the technical basis to future explore the resources of halophilic archaeon in Lop Nur regions.

  18. Magnesium Sulfate and Betamethasone Reduce NUR77 Expression in a Preterm Labor Mouse Model

    DTIC Science & Technology

    2016-06-29

    neurologic injury. MgSO4, however, prevents cerebral palsy in only 1 in 40 women who receive it. Understanding the cellular responses to MgSO4/BMTZ...could allow for more effective treatments. Nur77 is a nuclear receptor implicated in apoptosis and immune responses- processes that occur in

  19. Analysis of the ancient river system in Loulan period in Lop Nur region

    NASA Astrophysics Data System (ADS)

    Zhu, Jianfeng; Jia, Peng; Nie, Yueping

    2010-09-01

    The Lop Nur region is located in the east of the Tarim Basin. It has served as the strategic passage and communication hub of the Silk Road since Han Dynasty. During Wei-Jin period, the river system there was well developed and the ancient city of Loulan was bred there. In this study, GIS is used to accomplish automatic extraction of the river course in the Lop Nur region at first using ArcGIS. Then the RCI index is constituted to extract ancient river course from Landsat ETM image with band 3 and band 4. It is concluded that the north river course of Peacock River conformed before the end of the 4th century AD according to the distribution of the entire river course of the Lop Nur region. Later, the Peacock River changed its way to south to Tarim River, and flowed into Lop Nur along the direction paralleling Altun Mountain from west to east. It was the change of the river system that mainly caused the decrease in water supply around ancient city of Loulan before the end of 4th century. The ancient city of Loulan has been gradually ruined in the sand because of the absence of water supply since then.

  20. Enrichment of Nur77 mediated by RARβ leads to apoptosis of human hepatocellular carcinoma cells induced by fenretinide and HDACi

    PubMed Central

    Yang, Hui; Zhan, Qi; Wan, Yu-Jui Yvonne

    2010-01-01

    Synthetic retinoid fenretinide is one of the most promising clinically tested retinoids. Previously, we have shown that fenretinide induces apoptosis of Huh7 cells, but HepG2 cells are relatively resistant to fenretinide-induced apoptosis. The current study examines the interactive role of fenretinide and histone deacetylase inhibitors (HDACi) in inducing apoptosis of human hepatocellular carcinoma (HCC) cells and the underlying mechanism. Trichostatin A (TSA) and scriptaid can either enhance fenretinide-induced apoptosis in the fenretinide sensitive HCC cells (Huh7 and Hep3B) or sensitize the fenretinide resistant cells (HepG2) to become sensitive to the apoptotic effect of fenretinide in a cancer-cell specific manner. The sensitivity of cells to fenretinide-induced apoptosis was neither associated with ROS production nor anti-oxidant gene expression. However, the level of RARβ and Nur77 was important for inducing apoptosis. Upon fenretinide and HDACi treatment, the expression of RARβ and Nur77 were induced and co-localized in the cytosol. The induction of Nur77 protein level, but not the mRNA level, was RARβ-dependent. In addition, RARβ interacted with Nur77. Nur77 was essential for fenretinide- and HDACi-induced apoptosis of Huh7 cells. Induction of the expression, the interaction, and the nuclear export of RARβ and Nur77 mediate fenretinide and HDACi induced apoptosis. Our findings suggest that targeting Nur77 and RARβ simultaneously provides an effective way to induce HCC cell death. PMID:21319187

  1. Induction of Nur77-dependent apoptotic pathway by a coumarin derivative through activation of JNK and p38 MAPK.

    PubMed

    Zhou, Yuqi; Zhao, Wei; Xie, Guobin; Huang, Mingfeng; Hu, Mengjie; Jiang, Xin; Zeng, Dequan; Liu, Jie; Zhou, Hu; Chen, Haifeng; Wang, Guang-Hui; Zhang, Xiao-Kun

    2014-12-01

    Coumarins are plant-derived natural products with a broad range of known pharmacological activities including anticancer effects. However, the molecular mechanisms by which this class of promising compounds exerts their anticancer effects remain largely unknown. We report here that a furanocoumarin named apaensin could effectively induce apoptosis of cancer cells through its activation of Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Apoptosis induction by apaensin in cancer cells was suppressed by chemical inhibitors of JNK and p38 MAPK. Inhibition of the expression of orphan nuclear receptor Nur77 by small interfering RNA (siRNA) approach also abrogated the death effect of apaensin. Molecular analysis demonstrated that JNK activation was required for the nuclear export of Nur77, a known apoptotic event in cancer cells. Although p38 MAPK activation was not involved in Nur77 nuclear export, it was essential for Nur77 mitochondrial targeting through induction of Nur77 interaction with Bcl-2, which is also known to convert Bcl-2 from an antiapoptotic to a proapoptotic molecule. Together, our results identify a new natural product that targets orphan nuclear receptor Nur77 through its unique activation of JNK and p38 MAPK and provide insight into the complex regulation of the Nur77-Bcl-2 apoptotic pathway. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Induction of Nur77-dependent apoptotic pathway by a coumarin derivative through activation of JNK and p38 MAPK

    PubMed Central

    Zhou, Yuqi; Zhao, Wei; Xie, Guobin; Huang, Mingfeng; Hu, Mengjie; Jiang, Xin; Zeng, Dequan; Liu, Jie; Zhou, Hu; Chen, Haifeng; Zhang, Xiao-Kun

    2014-01-01

    Coumarins are plant-derived natural products with a broad range of known pharmacological activities including anticancer effects. However, the molecular mechanisms by which this class of promising compounds exerts their anticancer effects remain largely unknown. We report here that a furanocoumarin named apaensin could effectively induce apoptosis of cancer cells through its activation of Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Apoptosis induction by apaensin in cancer cells was suppressed by chemical inhibitors of JNK and p38 MAPK. Inhibition of the expression of orphan nuclear receptor Nur77 by small interfering RNA (siRNA) approach also abrogated the death effect of apaensin. Molecular analysis demonstrated that JNK activation was required for the nuclear export of Nur77, a known apoptotic event in cancer cells. Although p38 MAPK activation was not involved in Nur77 nuclear export, it was essential for Nur77 mitochondrial targeting through induction of Nur77 interaction with Bcl-2, which is also known to convert Bcl-2 from an antiapoptotic to a proapoptotic molecule. Together, our results identify a new natural product that targets orphan nuclear receptor Nur77 through its unique activation of JNK and p38 MAPK and provide insight into the complex regulation of the Nur77-Bcl-2 apoptotic pathway. PMID:25187486

  3. Differential roles for Bim and Nur77 in thymocyte clonal deletion induced by ubiquitous self-antigen.

    PubMed

    Hu, Qian Nancy; Baldwin, Troy A

    2015-03-15

    Negative selection, primarily mediated through clonal deletion of self-reactive thymocytes, is critical for establishing self-tolerance and preventing autoimmunity. Recent studies suggest that the molecular mechanisms of negative selection differ depending on the thymic compartment and developmental stage at which thymocytes are deleted. Using the physiological HY(cd4) TCR transgenic model of negative selection against ubiquitous self-antigen, we previously found that one of the principal mediators implicated in clonal deletion, Bim, is required for caspase-3 activation but is ultimately dispensable for negative selection. On the basis of these data, we hypothesized that Nur77, another molecule thought to be a key mediator of clonal deletion, could be responsible for Bim-independent deletion. Despite comparable Nur77 induction in thymocytes during negative selection, Bim deficiency resulted in an accumulation of high-affinity-signaled thymocytes as well as impairment in caspase-mediated and caspase-independent cell death. Although these data suggested that Bim may be required for Nur77-mediated cell death, we found that transgenic Nur77 expression was sufficient to induce apoptosis independently of Bim. However, transgenic Nur77-induced apoptosis was significantly inhibited in the context of TCR signaling, suggesting that endogenous Nur77 could be similarly regulated during negative selection. Although Nur77 deficiency alone did not alter positive or negative selection, combined deficiency in Bim and Nur77 impaired clonal deletion efficiency and significantly increased positive selection efficiency. Collectively, these data shed light on the different roles for Bim and Nur77 during ubiquitous Ag-mediated clonal deletion and highlight potential differences from their reported roles in tissue-restricted Ag-mediated clonal deletion.

  4. Orphan Nuclear Receptor Nur77 Inhibits Angiotensin II-Induced Vascular Remodeling via Downregulation of β-Catenin.

    PubMed

    Cui, Mingli; Cai, Zhaohua; Chu, Shichun; Sun, Zhe; Wang, Xiaolei; Hu, Liuhua; Yi, Jing; Shen, Linghong; He, Ben

    2016-01-01

    Angiotensin II (Ang II) is the predominant effector peptide of the renin-angiotensin system. Ang II contributes to vascular remodeling in many cardiovascular diseases (eg, hypertension, atherosclerosis, restenosis, and aneurysm). Orphan nuclear receptor Nur77 has a crucial role in the functional regulation of vascular cells. The objective of this study was to define the specific role of Nur77 in Ang II-induced vascular remodeling. Nur77 expression was initially found to be elevated in medial vascular smooth muscle cells (VSMCs) of thoracic aortas from mice continuously infused with Ang II for 2 weeks using a subcutaneous osmotic minipump. Cellular studies revealed that Nur77 expression was upregulated by Ang II via the MAPK/PKA-CREB signaling pathway. Ang II-induced proliferation, migration, and phenotypic switching were significantly enhanced in VSMCs isolated from Nur77(-/-) mice compared with wild-type VSMCs. Consistent with the role in VSMCs, we found that compared with wild-type mice, Nur77(-/-) mice had elevated aortic medial areas and luminal diameters, more severe elastin disruption and collagen deposition, increased VSMC proliferation and matrix metalloproteinase production, and decreased VSMC-specific genes SM-22α and α-actin expression, after 2 weeks of exogenous Ang II administration. The results of additional experiments suggested that Nur77 suppressed Ang II-induced β-catenin signaling pathway activation by promoting β-catenin degradation and inhibiting its transcriptional activity. Our findings indicated that Nur77 is a critical negative regulator of Ang II-induced VSMC proliferation, migration, and phenotypic switching via the downregulation of β-catenin activity. Nur77 may reduce Ang II-induced vascular remodeling involved in many cardiovascular diseases. © 2015 American Heart Association, Inc.

  5. [Al

    PubMed

    Purath; Köppe; Schnöckel

    1999-10-04

    A "naked" aluminum atom links two aluminum tetrahedra in the [Al(7){N(SiMe(3))(2)}(6)](-) ion (see picture), which results from the reaction of a metastable AlCl solution with LiN(SiMe(3))(2) and crystallizes with [Li(OEt(2))(3)](+) as cation. This unique structure among molecular metal atom clusters represents a small but characteristic section of cubic close-packed aluminum.

  6. The orphan nuclear receptor Nur77 inhibits low shear stress-induced carotid artery remodeling in mice.

    PubMed

    Yu, Ying; Cai, Zhaohua; Cui, Mingli; Nie, Peng; Sun, Zhe; Sun, Shiqun; Chu, Shichun; Wang, Xiaolei; Hu, Liuhua; Yi, Jing; Shen, Linghong; He, Ben

    2015-12-01

    Shear stress, particularly low and oscillatory shear stress, plays a critical pathophysiological role in vascular remodeling-related cardiovascular diseases. Growing evidence suggests that the orphan nuclear receptor Nur77 [also known as TR3 or nuclear receptor subfamily 4, group A, member 1 (NR4A1)] is expressed in diseased human vascular tissue and plays an important role in vascular physiology and pathology. In the present study, we used a mouse model of flow-dependent remodeling by partial ligation of the left common carotid artery (LCCA) to define the exact role of Nur77 in vascular remodeling induced by low shear stress. Following vascular remodeling, Nur77 was highly expressed in neointimal vascular smooth muscle cells (VSMCs) in the ligated carotid arteries. The reactive oxygen species (ROS) levels were elevated in the remodeled arteries in vivo and in primary rat VSMCs in vitro following stimulation with platelet-derived growth factor (PDGF). Further in vitro experiments revealed that Nur77 expression was rapidly increased in the VSMCs following stimulation with PDGF and H2O2, whereas treatment with N-acetyl cysteine (NAC, a ROS scavenger) reversed the increase in the protein level of Nur77 induced by H2O2. Moreover, Nur77 overexpression markedly inhibited the proliferation and migration of VSMCs, induced by PDGF. Finally, to determine the in vivo role of Nur77 in low shear stress-induced vascular remodeling, wild-type (WT) and Nur77-deficient mice were subjected to partial ligation of the LCCA. Four weeks following surgery, in the LCCAs of the Nur77‑deficient mice, a significant increase in the intima-media area and carotid intima-media thickness was noted, as well as more severe elastin disruption and collagen deposition compared to the WT mice. Immunofluorescence staining revealed an increase in VSMC proliferation [determined by the expression of proliferating cell nuclear antigen (PCNA)] and matrix metalloproteinase 9 (MMP-9) production in the Nur77

  7. A lacustrine record from Lop Nur, Xinjiang, China: Implications for paleoclimate change during Late Pleistocene

    USGS Publications Warehouse

    Chao, L.; Zicheng, P.; Dong, Y.; Weiguo, L.; Zhaofeng, Z.; Jianfeng, H.; Chenlin, C.

    2009-01-01

    Climate variability during the Late Pleistocene is studied from the proxies in core CK-2 drilled from the Luobei Depression (91??03???E, 40??47???N), Lop Nur in the eastern Tarim Basin, Xinjiang, China. Geophysical and geochemical properties, including magnetic susceptibility, granularity, chroma, carbonate content, loss on ignition and trace elements, have been determined to reconstruct the environmental evolution of the area during 32-9 ka BP. The chronology is established by uranium-thorium disequilibrium dating techniques. Our data suggest four paleoclimate stages, indicating glacial variations between cold-humid and warm-arid environments. A period of extreme humidity occurred during 31,900-19,200 yr BP is attributed the last glacial maximum (LGM). The period was followed by a warm-arid episode during 19,200-13,500 yr BP. Then a cold-humid interval during 13,500-12,700 yr BP may correspond to another cooling phases at high latitudes of the Northern Hemisphere. The last stage from 12,700 to 9000 yr BP has a trend that the climate turned warm and arid. The Lop Nur region is characterized by particularly humid stadials and arid interstadials. The climate variability in Lop Nur was constrained by global climate change because it is correlated with Dansgaard-Oeschger and Heinrich events, which were observed at the northern high latitudes. The synchroneity of the palaeoclimatic events suggested that cold air activity at the northern high latitudes was the most important factor that influenced the climate evolution in the Lop Nur region. A probable mechanism that involves the migration of westerly winds is proposed to interpret this synchroneity. ?? 2008 Elsevier Ltd.

  8. Nur1 Dephosphorylation Confers Positive Feedback to Mitotic Exit Phosphatase Activation in Budding Yeast

    PubMed Central

    Godfrey, Molly; Kuilman, Thomas; Uhlmann, Frank

    2015-01-01

    Substrate dephosphorylation by the cyclin-dependent kinase (Cdk)-opposing phosphatase, Cdc14, is vital for many events during budding yeast mitotic exit. Cdc14 is sequestered in the nucleolus through inhibitory binding to Net1, from which it is released in anaphase following Net1 phosphorylation. Initial Net1 phosphorylation depends on Cdk itself, in conjunction with proteins of the Cdc14 Early Anaphase Release (FEAR) network. Later on, the Mitotic Exit Network (MEN) signaling cascade maintains Cdc14 release. An important unresolved question is how Cdc14 activity can increase in early anaphase, while Cdk activity, that is required for Net1 phosphorylation, decreases and the MEN is not yet active. Here we show that the nuclear rim protein Nur1 interacts with Net1 and, in its Cdk phosphorylated form, inhibits Cdc14 release. Nur1 is dephosphorylated by Cdc14 in early anaphase, relieving the inhibition and promoting further Cdc14 release. Nur1 dephosphorylation thus describes a positive feedback loop in Cdc14 phosphatase activation during mitotic exit, required for faithful chromosome segregation and completion of the cell division cycle. PMID:25569132

  9. Study on the polarimetric characteristics of the Lop Nur arid area using PolSAR data

    NASA Astrophysics Data System (ADS)

    Gao, Zhihong; Gong, Huaze; Zhou, Xu; Shao, Yun; Yuan, Minghuan; Wang, Longfei

    2014-01-01

    The quantitative study of the arid Lop Nur lake basin is significant to investigate the environmental changes in the arid area of northwestern China and extremely arid areas of Eurasia in general. Synthetic aperture radar (SAR) imagery, with its penetration capability and advantages for studying geological phenomena on a large spatial scale, is very suitable for analyzing the subsurface of the Lop Nur area. Based on the full polarimetric ALOS PALSAR data and field investigation, it was found that the two-layer scattering mechanism of the dry sediments is very special and complex. The scattering mechanism in the bright strips is more complex than that in the gray strips according to the co-polarization correlation analysis. The experimental results show that the Cloude-Pottier decomposition method is more appropriate for this area. Moreover, the polarimetric characteristics and Cloude-Pottier decomposition results are very important for the study of the past climatic change in Lop Nur area. In conclusion, full polarimetric SAR data and target decomposition theory provide a new technique for obtaining information and quantitatively studying the subsurface characteristics of arid areas.

  10. Precise topography assessment of Lop Nur Lake Basin using GLAS altimeter

    NASA Astrophysics Data System (ADS)

    Wang, Longfei; Gong, Huaze; Shao, Yun

    2014-03-01

    Lop Nur is a dried-up salt lake lying in the eastern part of Tarim basin, which used to be the second largest lagon in China. The "ear" rings in Lop Nur attract many interests and are regarded as the lake shorelines during its recession. The topography of the lake basin is important in understanding the formation of the "ear" rings. In this paper, elevation data along three transects obtained from laser altimeter were taken as the basic material of the topography in Lop Nur. Elevation data of laser altimeter show great consistency between adjacent passes. Orthometric height (OH) derived from altimetry data and the geoid model are used to analyze the elevation characteristic along "ear" rings. The result shows the "ear" rings are basically identical in elevation, supporting the statement that "ear" rings are former lake shorelines. A discrepancy of approximately 1 meter in OH is observed on the same "ear" ring, lower in the north and higher in the south, which is found for the first time. Possible explanations could be deformation of ground surface due to earthquake or tectonic movement after the "ear" rings are formed, or tilt of water surface due to wind stress or lake current during the formation of the rings.

  11. Nur77 gene expression levels were involved in different ACTH-secretion autonomy between Cushing's disease and subclinical Cushing's disease.

    PubMed

    Tabuchi, Yukiko; Kitamura, Tetsuhiro; Fukuhara, Atsunori; Mukai, Kosuke; Onodera, Toshiharu; Miyata, Yugo; Hamasaki, Toshimitsu; Oshino, Satoru; Saitoh, Youichi; Morii, Eiichi; Otsuki, Michio; Shimomura, Iichiro

    2016-06-30

    Cushing's disease (CD) and subclinical Cushing's disease (subCD) are both diseases caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas. However, ACTH autonomy in subCD is weaker than in CD and there are no Cushingoid features in subCD. The differences of molecular mechanisms in ACTH autonomy between CD and subCD have not yet been reported. Therefore, we aimed to investigate the differences in molecular mechanisms of ACTH-secretion autonomy between CD and subCD. The study included 23 patients [7 CD, 6 subCD, and 10 non-functioning pituitary tumors (NFTs)] who underwent transsphenoidal surgery at the Osaka University Hospital between December 2009 and October 2013. Using quantitative real-time PCR, various ACTH-related gene expressions in tumor tissues from CD, subCD, and NFT were measured such as pro-opiomelanocortin (POMC), POMC transcription factor (Tpit, Pitx1, NeuroD1, and Nur77), POMC peptide processing enzymes (prohormone convertase: PC1/3 and PC2), and ACTH secretion-related factors (corticotropin-releasing hormone receptor 1: CRHR1 and glucocorticoid receptor α: GRα). Only Nur77 mRNA levels were significantly higher in CD than in subCD. Furthermore, we stained 6 CD and 6 subCD with anti-Nur77 antibody. All tumor samples from CD had Nur77 protein positive cells. On the other hand, Nur77 protein was expressed in only one tumor sample from subCD. This sample showed high expression of Nur77 mRNA. Nur77 is an important to regulate POMC transcription and negative-feedback by glucocorticoids. Nur77 gene expression levels might involve different autonomy of ACTH production between CD and subCD.

  12. The NR4A receptors Nurr1 and Nur77 are increased in human placenta from women with gestational diabetes.

    PubMed

    Lappas, M

    2014-11-01

    Members of the NR4A subfamily are involved in a wide range of diseases including obesity and diabetes. The aim of this study was to determine the effect of maternal obesity and gestational diabetes mellitus (GDM) on the expression of the NR4A receptors Nurr1, Nur77 and NOR1. Human placenta was obtained at the time of term Caesarean section from (i) lean and obese and normal glucose tolerant (NGT) pregnant women; and (ii) women with GDM and BMI-matched NGT women (n = 16 patients). Primary trophoblast cells, isolated from human term placenta, were used to determine the effect of pro-inflammatory cytokines on NR4A protein expression. Primary trophoblast cells were also used to assess the effect of Nurr1, Nur77 and NOR1 siRNA knockdown on pro-inflammatory cytokines. There was no effect of pre-existing maternal obesity on Nurr1, Nur77 or NOR1 expression. Nurr1 and Nur77 expression were significantly higher in GDM placenta compared to NGT placenta, and in the presence of the pro-inflammatory cytokines TNF-α and IL-β in primary trophoblast cells. Knockdown of Nurr1 and Nur77 in human primary trophoblast cells significantly decreased TNF-α induced expression and secretion of IL-6 and IL-8. Nurr1 and Nur77, which were increased in human placenta from women with GDM, are involved in TNF-α induced-expression of pro-inflammatory cytokines. Pro-inflammatory cytokines are known to play a role in placental nutrient transport. Thus, the regulation of pro-inflammatory cytokines by Nurr1 and Nur77 suggest that these proteins may play a role in placental function and transport mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Nur77 attenuates endothelin-1 expression via downregulation of NF-κB and p38 MAPK in A549 cells and in an ARDS rat model.

    PubMed

    Jiang, Yujie; Zeng, Yi; Huang, Xia; Qin, Yueqiu; Luo, Weigui; Xiang, Shulin; Sooranna, Suren R; Pinhu, Liao

    2016-12-01

    Acute respiratory distress syndrome (ARDS) is characterized by inflammatory injury to the alveolar and capillary barriers that results in impaired gas exchange and severe acute respiratory failure. Nuclear orphan receptor Nur77 has emerged as a regulator of gene expression in inflammation, and its role in the pathogenesis of ARDS is not clear. The objective of this study is to investigate the potential role of Nur77 and its underlying mechanism in the regulation of endothelin-1 (ET-1) expression in lipopolysaccharide (LPS)-induced A549 cells and an ARDS rat model. We demonstrate that LPS induced Nur77 expression and nuclear export in A549 cells. Overexpression of Nur77 markedly decreased basal and LPS-induced ET-1 expression in A549 cells, whereas knockdown of Nur77 increased the ET-1 expression. LPS-induced phosphorylation and nuclear translocation of NF-κB and p38 MAPK were blocked by Nur77 overexpression and augmented by Nur77 knockdown in A549 cells. In vivo, LPS induced Nur77 expression in lung in ARDS rats. Pharmacological activation of Nur77 by cytosporone B (CsnB) inhibited ET-1 expression in ARDS rats, decreased LPS-induced phosphorylation of NF-κB and p38 MAPK, and relieved lung, liver, and kidney injury. Pharmacological deactivation of Nur77 by 1,1-bis-(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH, C-DIM8) had no effect on ET-1 expression and lung injury. These results indicated that Nur77 decreases ET-1 expression by suppressing NF-κB and p38 MAPK in LPS-stimulated A549 cells in vitro, and, in an LPS-induced ARDS rat model, CsnB reduced ET-1 expression and lung injury in ARDS rats.

  14. Nur77 attenuates endothelin-1 expression via downregulation of NF-κB and p38 MAPK in A549 cells and in an ARDS rat model

    PubMed Central

    Jiang, Yujie; Zeng, Yi; Huang, Xia; Qin, Yueqiu; Luo, Weigui; Xiang, Shulin; Sooranna, Suren R.

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is characterized by inflammatory injury to the alveolar and capillary barriers that results in impaired gas exchange and severe acute respiratory failure. Nuclear orphan receptor Nur77 has emerged as a regulator of gene expression in inflammation, and its role in the pathogenesis of ARDS is not clear. The objective of this study is to investigate the potential role of Nur77 and its underlying mechanism in the regulation of endothelin-1 (ET-1) expression in lipopolysaccharide (LPS)-induced A549 cells and an ARDS rat model. We demonstrate that LPS induced Nur77 expression and nuclear export in A549 cells. Overexpression of Nur77 markedly decreased basal and LPS-induced ET-1 expression in A549 cells, whereas knockdown of Nur77 increased the ET-1 expression. LPS-induced phosphorylation and nuclear translocation of NF-κB and p38 MAPK were blocked by Nur77 overexpression and augmented by Nur77 knockdown in A549 cells. In vivo, LPS induced Nur77 expression in lung in ARDS rats. Pharmacological activation of Nur77 by cytosporone B (CsnB) inhibited ET-1 expression in ARDS rats, decreased LPS-induced phosphorylation of NF-κB and p38 MAPK, and relieved lung, liver, and kidney injury. Pharmacological deactivation of Nur77 by 1,1-bis-(3′-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH, C-DIM8) had no effect on ET-1 expression and lung injury. These results indicated that Nur77 decreases ET-1 expression by suppressing NF-κB and p38 MAPK in LPS-stimulated A549 cells in vitro, and, in an LPS-induced ARDS rat model, CsnB reduced ET-1 expression and lung injury in ARDS rats. PMID:27765761

  15. Provenance and Dispersal of Quaternary Sediments in the Gaxun Nur Basin, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Schimpf, S.; Diekmann, B.; Hartmann, K.; Wuennemann, B.; Zhang, C.

    2013-12-01

    The Gaxun Nur Basin is an intramontane accumulation area with one of the biggest continental alluvial fans in the world. It is situated in the western part of Inner Mongolia and its origin is the result of the interplay between tectonic activity and climate dynamics. Due to the endorheic character of the basin, it is predestined as a terrestrial longtime-archive of climate and environmental change. The sediments in the Gaxun Nur basin were deposited during the last 250 kyr by the Hei River System with a catchment size of roughly 130.000 km2. To understand the sedimentary processes of this huge sediment cascade from the Qilian Mountains in the south to the terminal lakes in the north, sources of sediments have to be investigated. Sediment provenance can be deduced from mineralogical fingerprints of modern sediments deposited along the recent pathways from the sources (Qilian Mountains) to the sink (Gaxun Nur Basin). The resulting spatial variation serves as a reference for the mineralogical data from a drilling core in the distal part of the Gaxun Nur Basin. Inferring spatial and temporal variation of sediment provenance provides important information for reconstructing sediment input by fluvial, eolian, lacustrine, and glacial processes. The methodical approach focusses on the analysis of clay and heavy minerals, using XRD and petrographic techniques. Other methods involve geochemistry of heavy mineral grains, using computer-controlled scanning electron microscope (CCSEM), as well as bulk geochemistry, XRF element scanning and a statistical data processing. In this poster we present geochemical and mineralogical data of a 20 m long sediment core (GN100) combined with the results of about 200 surface sediment samples from different archives of the whole Hei River catchment. Lithological changes in the drilling core reveal temporal variations in the depositional environment. These variations are related to alternating phases of fluvial and eolian activity supported

  16. Nur77 and retinoid X receptors: critical factors in dopamine-related neuroadaptation

    PubMed Central

    Lévesque, Daniel; Rouillard, Claude

    2017-01-01

    Dopaminergic systems in the brain adapt in response to a variety of stimuli from the internal and external world, but the mechanisms underlying this process are incompletely understood. In recent years, evidence has emerged that certain types of transcription factor of the nuclear receptor family, specifically Nur77 and retinoid X receptors, play an important role in the Nuradaptation, and importantly, in the homeostatic regulation, of dopaminergic systems. These findings call for a reassessment of our fundamental understanding of the molecular and cellular basis of dopaminergic transmission. Given that diseases such as Parkinson’s disease and schizophrenia are thought to involve maladaptation of dopamine signalling, these findings might lead new insight into these pathologies and offer new avenues for drug development. PMID:17134767

  17. Negative cross-talk between the human orphan nuclear receptor Nur77/NAK-1/TR3 and nuclear factor-kappaB.

    PubMed

    Harant, Hanna; Lindley, Ivan J D

    2004-01-01

    The effect of orphan nuclear receptor Nur77 overexpression on activation of an interleukin-2 (IL-2) promoter-luciferase construct was analyzed in the human leukemic cell line Jurkat. Cotransfection of the IL-2 promoter construct together with the Nur77 expression plasmid resulted in a significant repression of IL-2 promoter activation compared to control cells. The repression by Nur77 requires the N-terminal activation function-1 domain. The repressive effect of Nur77 on IL-2 promoter activation is mediated through inhibition of the transcription factor complex nuclear factor-kappaB (NF-kappaB), since blocking or alteration of the IL-2 NF-kappaB binding sites resulted in abrogation of the repressive effect of Nur77. Moreover, further examination of a reporter gene construct containing multiple copies of the IL-2 CD28 response element (CD28RE) showed that Nur77 can inhibit transactivation mediated by the NF-kappaB components p65 and c-Rel. However, no effect of Nur77 was seen on p65-mediated transactivation of a construct containing multiple NF-kappaB binding sites of the HIV LTR. Our data suggest that Nur77 is able to block activation through NF-kappaB when bound to low-affinity NF-kappaB binding sites, such as those located in the IL-2 promoter.

  18. Crystallization and preliminary X-ray crystallographic analyses of Nur, a nickel-responsive transcription regulator from Streptomyces coelicolor

    SciTech Connect

    An, Young Jun; Ahn, Bo-Eun; Roe, Jung-Hye; Cha, Sun-Shin

    2008-02-01

    A nickel uptake regulator (Nur) from Streptomyces coelicolor has been crystallized. A 2.4 Å native data set and a 3.0 Å Ni-MAD data set were collected using synchrotron radiation. Nickel ions serve in the correct folding and function of microbial enzymes implicated in metabolic processes. Although nickel ions are indispensable for the survival of cells, the intracellular level of nickel ions needs to be properly maintained as excessive levels of nickel ions are toxic. Nur, a nickel-uptake regulator belonging to the Fur family, is a nickel-responsive transcription factor that controls nickel homeostasis and antioxidative response in Streptomyces coelicolor. Nur was purified and crystallized at 295 K. A 2.4 Å native data set and a 3.0 Å Ni-MAD data set were collected using synchrotron radiation. The Nur crystals belong to space group P3{sub 1}, with unit-cell parameters a = b = 78.17, c = 50.39 Å. Assuming the presence of two molecules in the asymmetric unit, the solvent content is estimated to be about 54.7%.

  19. Kommunikation in Automatisierungssystemen

    NASA Astrophysics Data System (ADS)

    Wellenreuther, Günter; Zastrow, Dieter

    Die Automatisierungstechnik befindet sich im Umbruch. Durch Anwendung moderner Kommunikationstechnik erhofft man sich entscheidende Verbesserungen bei Effizienz und Flexibilität der Automatisierungsprozesse. Der Begriff der Automatisierungstechnik umfasst heute mehr als nur das Automatisieren im Sinne von Steuern, Regeln und Visualisieren, eingeschlossen ist auch das Kommunizieren.

  20. Ginsenoside 20(S)-Rh2 Induces Apoptosis and Differentiation of Acute Myeloid Leukemia Cells: Role of Orphan Nuclear Receptor Nur77.

    PubMed

    Wang, Chengqiang; He, Hui; Dou, Guojun; Li, Juan; Zhang, Xiaomei; Jiang, Mingdong; Li, Pan; Huang, Xiaobo; Chen, Hongxi; Li, Li; Yang, Dajian; Qi, Hongyi

    2017-09-06

    Ginsenoside 20(S)-Rh2 has been shown to induce apoptosis and differentiation of acute myeloid leukemia (AML) cells. However, the underlying molecular mechanisms are not fully understood. In our study, 20(S)-Rh2 induced the expression of orphan nuclear receptor Nur77 and death receptor proteins Fas, FasL, DR5, and TRAIL, as well as the cleavage of caspase 8 and caspase 3 in HL-60 cells. Importantly, shNur77 attenuated 20(S)-Rh2-induced apoptosis and Fas and DR5 expression. Meanwhile, 20(S)-Rh2 promoted Nur77 translocation from the nucleus to mitochondria and enhanced the interaction between Nur77 and Bcl-2, resulting in the exposure of the BH3 domain of Bcl-2 and activation of Bax. Furthermore, 20(S)-Rh2 promoted the differentiation of HL-60 cells as evidenced by Wright-Giemsa staining, NBT reduction assay, and detection of the myeloid differentiation marker CD11b by flow cytometry. Notably, shNur77 reversed 20(S)-Rh2-mediated HL-60 differentiation. Additionally, 20(S)-Rh2 also exhibited an antileukemic effect and induced Nur77 expression in NOD/SCID mice with the injection of HL-60 cells into the tail vein. Together, our studies suggest that the Nur77-mediated signaling pathway is highly involved in 20(S)-Rh2-induced apoptosis and differentiation of AML cells.

  1. Halalkalicoccus paucihalophilus sp. nov., a halophilic archaeon from Lop Nur region in Xinjiang, northwest of China.

    PubMed

    Liu, Bing-Bing; Tang, Shu-Kun; Zhang, Yong-Guang; Lu, Xin-Hua; Li, Li; Cheng, Juan; Zhang, Yuan-Ming; Zhang, Li-Li; Li, Wen-Jun

    2013-05-01

    Two extremely halophilic archaea, designated YIM 93701(T) and YIM 93664, were isolated from Lop Nur region in Xinjiang Province, northwest of China. The cells of the two strains were observed to be cocci, non-motile and Gram-negative. The organisms were determined to be aerobic and required at least 6 % NaCl for growth (optimum 20-25 % and maximum 35 %). Growth was found to occur in the ranges of 16-50 °C (optimum 37 °C) and pH 6.0-8.5 (optimum 6.5-7.5). Cells did not lyse in distilled water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains belongs to the genus Halalkalicoccus and possessed 99.3 and 99.5 % similarities with their closest phylogenetic relative Halalkalicoccus tibetensis JCM 11890(T). Major polar lipids of the two strains were determined to be phosphatidylglycerol(PG),phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and three unidentified glycolipids. The DNA G+C contents were determined to be 60.0-60.4 mol%. The DNA hybridization between the two strains was 92.0 %. In addition, the hybridizations of both strains to H. tibetensis were 49 and 52 %, respectively, and to Halalkalicoccus jeotali were 38 and 33 %, respectively. On the basis of physiological, biochemical tests and phylogenetic differentiations, strains YIM 93701(T) and YIM 93664 were classified as the same species which represent a novel species in the genus Halalkalicoccus, for which the name Halalkalicoccus paucihalophilus sp. nov. is proposed. The type strain is YIM 93701(T) (=JCM 17505(T) = CCTCC 2012803(T)).

  2. Saccharothrix lopnurensis sp. nov., a filamentous actinomycete isolated from sediment of Lop Nur.

    PubMed

    Li, Yu-Qian; Liu, Lan; Cheng, Cong; Shi, Xiao-Han; Lu, Chun-Yan; Dong, Zhou-Yan; Salam, Nimaichand; An, Deng-Di; Li, Wen-Jun

    2015-10-01

    A novel actinomycete strain, designated YIM LPA2h(T), was isolated from a sediment sample collected from Lop Nur, Xinjiang Uygur Autonomous Region, North-West China. The taxonomic position of strain YIM LPA2h(T) was investigated by a polyphasic approach. The morphological and chemotaxonomic properties of the isolate were in accordance with the members of the genus Saccharothrix. The 16S rRNA gene sequence of the strain showed highest similarities to Saccharothrix yanglingensis (98.6 %), Saccharothrix longispora (98.4 %) and Saccharothrix hoggarensis (98.3 %). However, the DNA-DNA hybridization values between the new isolate YIM LPA2h(T) and S. yanglingensis, S. longispora and S. hoggarensis were significantly below 70 %. Strain YIM LPA2h(T) was found to contain meso-diaminopimelic acid as diagnostic diamino acid. The major sugars in whole-cell hydrolysates were rhamnose, galactose, mannose, glucose and fructose. The major polar lipids were identified as phosphatidylethanolamine, phosphatidylhydroxylethanolamine, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The predominant respiratory menaquinones were MK-9 (H4) and MK-10 (H4). The major fatty acids were C17:1 ω8c (15 %), iso-C15:0 (12 %), anteiso-C15:0 (12 %) and summed feature 3 (C16:1 ω6c/C16:1 ω7c, 10 %). The genomic DNA G+C content of strain YIM LPA2h(T) was determined to be 75 mol %. The genotypic and phenotypic results suggest that strain YIM LPA2h(T) represents a novel species of the genus Saccharothrix, for which the name Saccharothrix lopnurensis sp. nov. is proposed. The type strain is YIM LPA2h(T) (=CGMCC 4.7246(T)=KCTC 39545(T)).

  3. Streptomyces xinjiangensis sp. nov., an actinomycete isolated from Lop Nur region.

    PubMed

    Cheng, Cong; Li, Yu-Qian; Asem, Mipeshwaree Devi; Lu, Chun-Yan; Shi, Xiao-Han; Chu, Xiao; Zhang, Wan-Qin; Di An, Deng-; Li, Wen-Jun

    2016-10-01

    A novel actinobacterial strain, designated LPA192(T), was isolated from a soil sample collected from Lop Nur, Xinjiang Uygur Autonomous Region, Northwest China. A polyphasic approach was used to investigate the taxonomic position of strain LPA192(T). The isolate showed morphological and chemotaxonomic characteristics typical of members of the genus Streptomyces. Peptidoglycan was found to contain LL-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were MK-9(H6) and MK-10(H4). Polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylinositol. Major cellular fatty acids consist of C16:0, anteiso-C15:0 and C18:1 ω9c. The sugar in whole-cell hydrolysates was mannose. Phylogenetic analysis indicated that strain LPA192(T) is closely related to Streptomyces tanashiensis LMG 20274(T) (99.3 %), Streptomyces gulbargensis DAS131(T) (99.3 %), Streptomyces nashvillensis NBRC 13064(T) (99.3 %), Streptomyces roseolus NBRC 12816(T) (99.2 %) and Streptomyces filamentosus NBRC 12767(T) (99.1 %) while showing below 98.5 % sequencing similarities with other validly published Streptomyces species. However, DNA-DNA relatedness values between LPA192(T) and the closely related type strains were below 40 %, which are much lower than 70 % threshold value for species delineation. The genomic DNA G + C content of strain LPA192(T) was 69.3 mol %. Based on the differences in genotypic and phenotypic characteristics from the closely related strains, strain LPA192(T) is considered to represent a novel species of the genus Streptomyces for which the name Streptomyces xinjiangensis sp. nov. is proposed. The type strain is LPA192(T) (=KCTC 39601(T) = CGMCC 4.7288(T)).

  4. Identification by DNA macroarray of nur77 as a gene induced by di-n-butyltin dichloride: its role in organotin-induced apoptosis.

    PubMed

    Gennari, Alessandra; Bleumink, Rob; Viviani, Barbara; Galli, Corrado Lodovico; Marinovich, Marina; Pieters, Raymond; Corsini, Emanuela

    2002-05-15

    The thymotoxic organotin compounds di-n-butyltin dichloride (DBTC) and tri-n-butyltin chloride (TBTC) are known to induce apoptosis in vitro in rat thymocytes. They also affect macromolecular synthesis, inhibiting DNA synthesis and increasing RNA synthesis. Since these RNA molecules, likely to be involved in the initiation of the apoptotic process, have not been identified yet, the purpose of this research was to characterize by a cDNA macroarray the expression of genes involved in DBTC-induced apoptosis. We found that nur77 was rapidly transcripted in vitro following exposure of freshly isolated rat thymocytes to 3 microM DBTC. nur77 induction has also been observed in vivo after treatment of rats with apoptotic doses (60 mg/kg body wt) of DBTC. The products of nur77 are known to be involved in the apoptotic process, as nur77 is a transcription factor expressed in response to T-cell receptor-mediated apoptosis in immature T cells. Antisense oligonucleotide inhibition of nur77 expression prevented apoptosis induced by DBTC, supporting a role for nur77 in organotin-induced apoptotic cell death.

  5. Der Einfluss der Digitalisierung auf die Organisation eines Unternehmens

    NASA Astrophysics Data System (ADS)

    Walter, Wolfram M.

    Die Digitalisierung schreitet mit großen Schritten voran. Dies wirkt sich nicht nur auf die Gesellschaft im Grundsatz, sondern auch auf das Verhalten der Kunden aus. Neue Kommunikationswege beschleunigen die Interaktion zwischen Unternehmen und Verbraucher. Im Vergleich mit großen Internetfirmen werden etablierte Dienstleistungsunternehmen - vom Energieversorger bis zu Versicherungen - stark unter Druck gesetzt, sich noch intensiver mit dem Kundenservice auseinanderzusetzen. Dies wird nur möglich sein, wenn sich die Organisationen entsprechend positionieren und sich frühzeitig auf die Veränderungen einstellen. Hieraus ergeben sich mehr Chancen als Risiken, zumal es nicht nur neue Prozesse, sondern auch neue Berufsbilder geben wird.

  6. Neutron spectrum measurements at a radial beam port of the NUR research reactor using a Bonner spheres spectrometer.

    PubMed

    Mazrou, H; Nedjar, A; Seguini, T

    2016-08-01

    This paper describes the measurement campaign held around the neutron radiography (NR) facility of the Algerian 1MW NUR research reactor. The main objective of this work is to characterize accurately the neutron beam provided at one of the radial channels of the NUR research reactor taking benefit of the acquired CRNA Bonner spheres spectrometer (BSS). The specific objective was to improve the image quality of the NR facility. The spectrometric system in use is based on a central spherical (3)He thermal neutron proportional counter combined with high density polyethylene spheres of different diameters ranging from 3 to 12in. This counting system has good gamma ray discrimination and is able to cover an energy range from thermal to 20MeV. The measurements were performed at the sample distance of 0.6m from the beam port and at a height of 1.2m from the facility floor. During the BSS measurements, the reactor was operating at low power (100W) to avoid large dead times, pulse pileup and high level radiation exposures, in particular, during spheres handling. Thereafter, the neutron spectrum at the sample position was unfolded by means of GRAVEL and MAXED computer codes. The thermal, epithermal and fast neutron fluxes, the total neutron flux, the mean energy and the Cadmium ratio (RCd) were provided. A sensitivity analysis was performed taking into account various defaults spectra and ultimately a different response functions in the unfolding procedure. Overall, from the obtained results it reveals, unexpectedly, that the measured neutron spectrum at the sample position of the neutron radiography of the NUR reactor is being harder with a predominance of fast neutrons (>100keV) by about 60%. Finally, those results were compared to previous and more recent measurements obtained by activation foils detectors. The agreement was fairly good highlighting thereby the consistency of our findings.

  7. Enrichment of Nur77 mediated by retinoic acid receptor β leads to apoptosis of human hepatocellular carcinoma cells induced by fenretinide and histone deacetylase inhibitors.

    PubMed

    Yang, Hui; Zhan, Qi; Wan, Yu-Jui Yvonne

    2011-03-01

    The synthetic retinoid fenretinide is one of the most promising clinically tested retinoids. Previously, we have shown that fenretinide induces apoptosis of Huh7 cells, but HepG2 cells are relatively resistant to fenretinide-induced apoptosis. This study examines the interactive role of fenretinide and histone deacetylase inhibitors (HDACi) in inducing apoptosis of human hepatocellular carcinoma (HCC) cells and the underlying mechanism. Trichostatin A and scriptaid can either enhance fenretinide-induced apoptosis in the fenretinide sensitive HCC cells (Huh7 and Hep3B) or sensitize the fenretinide resistant cells (HepG2) to become sensitive to the apoptotic effect of fenretinide in a cancer cell-specific manner. The sensitivity of cells to fenretinide-induced apoptosis was not associated with reactive oxygen species production nor with antioxidant gene expression. However, the level of retinoic acid receptor β (RARβ) and Nur77 (NR4A1) was important for inducing apoptosis. Upon fenretinide and HDACi treatment, the expression of RARβ and Nur77 were induced and colocalized in the cytosol. The induction of Nur77 protein level, but not the messenger RNA level, was RARβ-dependent. In addition, RARβ interacted with Nur77. Nur77 was essential for fenretinide-induced and HDACi-induced apoptosis of Huh7 cells. Induction of the expression, the interaction, and the nuclear export of RARβ and Nur77 mediate fenretinide-induced and HDACi-induced apoptosis. Our findings suggest that targeting Nur77 and RARβ simultaneously provides an effective way to induce HCC cell death. Copyright © 2010 American Association for the Study of Liver Diseases.

  8. Instandhaltungsmanagement als Gestaltungsfeld Ganzheitlicher Produktionssysteme

    NASA Astrophysics Data System (ADS)

    Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo

    Sich kontinuierlich verändernde Rahmenbedingungen, wie beispielsweise eine steigende Variantenvielfalt, verkürzte Produktlebenszyklen sowie Kundenforderungen nach höherer Qualität, kürzeren Lieferzeiten und geringeren Kosten, fordern von produzierenden Unternehmen eine stetige Anpassung der Prozesse, der Organisation und der Strukturen. Seit den 90er Jahren versuchen immer mehr deutsche Unternehmen diesen veränderten Anforderungen mit der Einführung eines Ganzheitlichen Produktionssystems (GPS) zu begegnen. Ganzheitliche Produktionssysteme sind dabei in ihren Grundlagen an das Toyota Produktionssystem angelehnt, vereinigen aber auch weitere Methoden zu einem unternehmensspezifischen Regelwerk. Im Rahmen des langfristigen Trends zu unternehmensindividuellen Produktionssystemen wird sowohl in der Industrie als auch in der Forschung intensiv über das Toyota Produktionssystem, Lean Production, Lean Management und Ganzheitliche Produktionssysteme diskutiert, werden Konzepte zu Implementierung und Betrieb erstellt und die Wirtschaftlichkeit untersucht.

  9. ERK1/2 deactivation enhances cytoplasmic Nur77 expression level and improves the apoptotic effect of fenretinide in human liver cancer cells.

    PubMed

    Yang, Hui; Nie, Yuqiang; Li, Yuyuan; Wan, Yu-Jui Yvonne

    2011-04-01

    Fenretinide, a synthetic retinoid, is a promising anticancer agent based on many in vitro, animal, and chemoprevention clinical trial studies. However, cells such as HepG2 human liver cancer cells are resistant to the apoptotic effect of fenretinide. Previously, we have shown that fenretinide-induced apoptosis is Nur77 dependent, and the sensitivity of the cancer cells to fenretinide-induced apoptosis is positively associated with cytoplasmic enrichment of Nur77. The goal of current study was to identify means to modulate nuclear export of Nur77 in order to improve the efficacy of fenretinide. Fenretinide treatment deactivated ERK1/2 in Huh7 cells, but activated ERK1/2 in HepG2 cells, which was positively associated with the sensitivity of cells to the apoptotic effect of fenretinide. Neither fenretinide nor ERK1/2 inhibitor PD98059 alone could affect the survival of HepG2 cells, but the combination of both induced cell death and increased caspase 3/7 activity. In fenretinide sensitive Huh7 cells, activation of ERK1/2 by epidermal growth factor (EGF) prevented fenretinide-induced cell death and caspase 3/7 induction. In addition, modulation of ERK1/2 changed the intracellular localization of Nur77. Fenretinide/PD98059-induced cell death of HepG2 cell was positively associated with induction and cytoplasmic location as well as mitochondria enrichment of Nur77. The effect was specific for ERK1/2 because other mitogen activated protein kinases such as P38, Akt, and JNK did not have correlated changes in their phosphorylation levels. Taken together, the current study demonstrates that ERK1/2-modulated Nur77 intracellular location dictates the efficacy of fenretinide-induced apoptosis. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. ERK1/2 deactivation enhances cytoplasmic Nur77 expression level and improves the apoptotic effect of fenretinide in human liver cancer cells

    PubMed Central

    Yang, Hui; Nie, Yuqiang; Li, Yuyuan; Wan, Yu-Jui Yvonne

    2011-01-01

    Fenretinide, a synthetic retinoid, is a promising anticancer agent based on many in vitro, animal, and chemoprevention clinical trial studies. However, cells such as HepG2 human liver cancer cells are resistant to the apoptotic effect of fenretinide. Previously, we have shown that fenretinide-induced apoptosis is Nur77 dependent, and the sensitivity of the cancer cells to fenretinide-induced apoptosis is positively associated with cytoplasmic enrichment of Nur77. The goal of current study was to identify means to modulate nuclear export of Nur77 in order to improve the efficacy of fenretinide. Fenretinide treatment deactivated ERK1/2 in Huh7 cells, but activated ERK1/2 in HepG2 cells, which was positively associated with the sensitivity of cells to the apoptotic effect of fenretinide. Neither fenretinide nor ERK1/2 inhibitor PD98059 alone could affect the survival of HepG2 cells, but the combination of both induced cell death and increased caspase 3/7 activity. In fenretinide sensitive Huh7 cells, activation of ERK1/2 by epidermal growth factor (EGF) prevented fenretinide-induced cell death and caspase 3/7 induction. In addition, modulation of ERK1/2 changed the intracellular localization of Nur77. Fenretinide/PD98059-induced cell death of HepG2 cell was positively associated with induction and cytoplasmic location as well as mitochondria enrichment of Nur77. The effect was specific for ERK1/2 because other mitogen activated protein kinases such as P38, Akt, and JNK did not have correlated changes in their phosphorylation levels. Taken together, the current study demonstrates that ERK1/2-modulated Nur77 intracellular location dictates the efficacy of fenretinide-induced apoptosis. PMID:21241664

  11. Minocycline ameliorates LPS-induced inflammation in human monocytes by novel mechanisms including LOX-1, Nur77 and LITAF inhibition

    PubMed Central

    Pang, Tao; Wang, Juan; Benicky, Julius; Saavedra, Juan M.

    2012-01-01

    Background Minocycline exhibits anti-inflammatory properties independent of its antibiotic activity, ameliorating inflammatory responses in monocytes and macrophages. However, the mechanisms of minocycline anti-inflammatory effects are only partially understood. Methods Human circulating monocytes were cultured in the presence of lipopolysaccharide (LPS), 50 ng/ml, and minocycline (10–40 µM). Gene expression was determined by RT-PCR, cytokine and prostaglandin E2 (PGE2) release by ELISA, protein expression, phosphorylation and nuclear translocation by Western blotting. Results Minocycline significantly reduced the inflammatory response in LPS-challenged monocytes, decreasing LPS-induced transcription of pro-inflammatory tumor-necrosis factor alpha (TNF-α), interleukin-1 beta, interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2), and the LPS-stimulated TNF-α, IL-6 and PGE2 release. Minocycline inhibited LPS-induced activation of the lectin-like oxidized low density lipoprotein receptor-1 (LOX-1), NF-κB, LPS-induced TNF-α factor (LITAF) and the Nur77 nuclear receptor. Mechanisms involved in the anti-inflammatory effects of minocycline include a reduction of LPS-stimulated p38 mitogen-activated protein kinase (p38 MAPK) activation and stimulation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Conclusions We provide novel evidence demonstrating that the anti-inflammatory effects of minocycline in human monocytes include, in addition to decreased NF-κB activation, abrogation of the LPS-stimulated LOX-1, LITAF, Nur77 pathways, p38 MAPK inhibition and PI3K/Akt activation. Our results reveal that minocycline inhibits points of convergence of distinct and interacting signaling pathways mediating multiple inflammatory signals which may influence monocyte activation, traffic and recruitment into the brain. General significance Our results in primary human monocytes contribute to explain the profound anti-inflammatory and protective effects of minocycline in

  12. Perturbation of transcription factor Nur77 expression mediated by myocyte enhancer factor 2D (MEF2D) regulates dopaminergic neuron loss in response to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

    PubMed

    Mount, Matthew P; Zhang, Yi; Amini, Mandana; Callaghan, Steve; Kulczycki, Jerzy; Mao, Zixu; Slack, Ruth S; Anisman, Hymie; Park, David S

    2013-05-17

    We have earlier reported the critical nature of calpain-CDK5-MEF2 signaling in governing dopaminergic neuronal loss in vivo. CDK5 mediates phosphorylation of the neuronal survival factor myocyte enhancer factor 2 (MEF2) leading to its inactivation and loss. However, the downstream factors that mediate MEF2-regulated survival are unknown. Presently, we define Nur77 as one such critical downstream survival effector. Following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in vivo, Nur77 expression in the nigrostriatal region is dramatically reduced. This loss is attenuated by expression of MEF2. Importantly, MEF2 constitutively binds to the Nur77 promoter in neurons under basal conditions. This binding is lost following 1-methyl-4-phenylpyridinium treatment. Nur77 deficiency results in significant sensitization to dopaminergic loss following 1-methyl-4-phenylpyridinium/MPTP treatment, in vitro and in vivo. Furthermore, Nur77-deficient MPTP-treated mice displayed significantly reduced levels of dopamine and 3,4-Dihydroxyphenylacetic acid in the striatum as well as elevated post synaptic FosB activity, indicative of increased nigrostriatal damage when compared with WT MPTP-treated controls. Importantly, this sensitization in Nur77-deficient mice was rescued with ectopic Nur77 expression in the nigrostriatal system. These results indicate that the inactivation of Nur77, induced by loss of MEF2 activity, plays a critical role in nigrostriatal degeneration in vivo.

  13. Direct binding of Nur77/NAK-1 to the plasminogen activator inhibitor 1 (PAI-1) promoter regulates TNF alpha -induced PAI-1 expression.

    PubMed

    Gruber, Florian; Hufnagl, Peter; Hofer-Warbinek, Renate; Schmid, Johannes A; Breuss, Johannes M; Huber-Beckmann, Renate; Lucerna, Markus; Papac, Nikolina; Harant, Hanna; Lindley, Ivan; de Martin, Rainer; Binder, Bernd R

    2003-04-15

    Plasminogen activator inhibitor 1 (PAI-1) is the main fibrinolysis inhibitor, and high plasma levels are associated with an increased risk for vascular diseases. Inflammatory cytokines regulate PAI-1 through a hitherto unclear mechanism. Using reporter gene analysis, we could identify a region in the PAI-1 promoter that contributes to basal expression as well as to tumor necrosis factor alpha (TNFalpha) induction of PAI-1 in endothelial cells. Using this region as bait in a genetic screen, we could identify Nur77 (NAK-1, TR3, NR4A1) as an inducible DNA-binding protein that binds specifically to the PAI-1 promoter. Nur77 drives transcription of PAI-1 through direct binding to an NGFI-B responsive element (NBRE), indicating monomeric binding and a ligand-independent mechanism. Nur77, itself, is transcriptionally up-regulated by TNFalpha. High expression levels of Nur77 and its colocalization with PAI-1 in atherosclerotic tissues indicate that the described mechanism for PAI-1 regulation may also be operative in vivo.

  14. NurA Is Endowed with Endo- and Exonuclease Activities that Are Modulated by HerA: New Insight into Their Role in DNA-End Processing

    PubMed Central

    De Falco, Mariarosaria; Catalano, Federico; Rossi, Mosè; Ciaramella, Maria; De Felice, Mariarita

    2015-01-01

    The nuclease NurA and the ATPase HerA are present in all known thermophilic archaea and cooperate with the highly conserved MRE11/RAD50 proteins to facilitate efficient DNA double-strand break end processing during homologous recombinational repair. However, contradictory results have been reported on the exact activities and mutual dependence of these two enzymes. To understand the functional relationship between these two enzymes we deeply characterized Sulfolobus solfataricus NurA and HerA proteins. We found that NurA is endowed with exo- and endonuclease activities on various DNA substrates, including linear (single-stranded and double stranded) as well as circular molecules (single stranded and supercoiled double-stranded). All these activities are not strictly dependent on the presence of HerA, require divalent ions (preferably Mn2+), and are inhibited by the presence of ATP. The endo- and exonculease activities have distinct requirements: whereas the exonuclease activity on linear DNA fragments is stimulated by HerA and depends on the catalytic D58 residue, the endonuclease activity on circular double-stranded DNA is HerA-independent and is not affected by the D58A mutation. On the basis of our results we propose a mechanism of action of NurA/HerA complex during DNA end processing. PMID:26560692

  15. Orphan Receptor TR3/nur77 and Apoptosis in Prostate Cancer Cells

    DTIC Science & Technology

    2004-07-01

    separate pages. Please supply glossy originals Subscribe to the journal Contains important review articles - All papers peer - reviewed - Reports... androgen - insensitive state (Coffey et al. ruption of PTEN leads to suppression of apoptosis 2001). Increased levels of Bcl-2 are associated with emerg...Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions

  16. NDRG1 promotes growth of hepatocellular carcinoma cells by directly interacting with GSK-3β and Nur77 to prevent β-catenin degradation.

    PubMed

    Lu, Wen-Jing; Chua, Mei-Sze; Wei, Wei; So, Samuel K

    2015-10-06

    The N-myc downstream regulated gene 1 (NDRG1) is significantly associated with advanced tumor stages and poor survival of hepatocellular carcinoma (HCC), thereby implicating it as a potential target for HCC treatment. We aim to further understand its biological roles in hepatocarcinogenesis, as a means to exploit it for therapeutic purposes. By screening using the ProtoArray® Human Protein Microarrays, we identified glycogen synthase kinase 3β (GSK-3β) and the orphan nuclear receptor (Nur77) as potential interaction partners of NDRG1. These interactions were confirmed in HCC cell lines in vitro by co-immunoprecipitation; and co-localizations of NDRG1 with GSK-3β and Nur77 were observed by immunofluorescence staining. Additionally, high levels of NDRG1 competitively bind to GSK-3β and Nur77 to allow β-catenin to escape degradation, with consequent elevated levels of downstream oncogenic genes. In vivo, we consistently observed that NDRG1 suppression in HCC xenografts decreased β-catenin levels and its downstream target Cyclin D1, with concomitant tumor growth inhibition. Clinically, the over-expression of NDRG1 in HCC patient samples is positively correlated with GSK-3β-9ser (|”‚ R | = 0.28, p = 0.01), Nur77 (|”‚ R | = 0.42, p < 0.001), and β-catenin (| R |= 0.32, p = 0.003) expressions. In conclusion, we identified GSK-3β and Nur77 as novel interaction partners of NDRG1. These protein-protein interactions regulate the turnover of β-catenin and subsequent downstream signaling mediated by β-catenin in HCC cells, and provides potential targets for future therapeutic interventions.

  17. Improvements in the Image Quality of Neutron Radiograms of NUR Neutron Radiography Facility by Using Several Exposure Techniques

    SciTech Connect

    Zergoug, T.; Nedjar, A.; Mokeddem, M. Y.; Mammou, L.

    2008-03-17

    Since the construction of NUR reactor neutron radiography facility in 1991, only transfer exposure method was used as a non destructive technique. The reason is the excess of gamma rays in the neutron beam. To improve radiation performances of the NR system, a stainless steal hollow conical cylinder is introduced at the bottom of the facility beam port, this filter reduce gamma infiltration through the edges of the NR structure without disturbing neutron beam arriving from the in pool divergent collimator. First results confirm our prediction; a gamma rays diminution and a relatively stable neutron flux at the point object are confirmed, consequently the n/{gamma} ratio reaches a value of 2.104 n/cm{sup 2} mR. Radiograms obtained by using the direct exposure method reveal the feasibility of the technique in the new NR configuration facility, but a weak resolution and contrast of the image is observed. In this paper, we describe a procedure to improve the image quality obtained by direct exposure technique. The process consists of using digitized images obtained by several exposure techniques (NR, gamma radiography or X radiography) for a comparison study and then better image definition can be attained.

  18. Involvement of TR3/Nur77 translocation to the endoplasmic reticulum in ER stress-induced apoptosis

    SciTech Connect

    Liang Bin; Song Xuhong; Liu Gefei; Li Rui; Xie Jianping; Xiao Lifeng; Du Mudan; Zhang Qiaoxia; Xu Xiaoyuan; Gan Xueqiong; Huang Dongyang . E-mail: huangdy@stu.edu.cn

    2007-08-01

    Nuclear orphan receptor TR3/Nur77/NGFI-B is a novel apoptotic effector protein that initiates apoptosis largely by translocating from the nucleus to the mitochondria, causing the release of cytochrome c. However, it is possible that TR3 translocates to other organelles. The present study was designed to determine the intracellular localization of TR3 following CD437-induced nucleocytoplasmic translocation and the mechanisms involved in TR3-induced apoptosis. In human neuroblastoma SK-N-SH cells and human esophageal squamous carcinoma EC109 and EC9706 cells, 5 {mu}M CD437 induced translocation of TR3 to the endoplasmic reticulum (ER). This distribution was confirmed by immunofluorescence analysis, subcellular fractionation analysis and coimmunoprecipitation analysis. The translocated TR3 interacted with ER-targeting Bcl-2; initiated an early release of Ca{sup 2+} from ER; resulted in ER stress and induced apoptosis through ER-specific caspase-4 activation, together with induction of mitochondrial stress and subsequent activation of caspase-9. Our results identified a novel distribution of TR3 in the ER and defined two parallel mitochondrial- and ER-based pathways that ultimately result in apoptotic cell death.

  19. Multi-proxy evidence for Late Pleistocene-Holocene climatic and environmental changes in Lop-Nur, Xinjiang, Northwest China

    USGS Publications Warehouse

    Luo, C.; Yang, D.; Peng, Z.; Zhang, Z.; Weiguo, L.; He, J.; Zhou, C.

    2008-01-01

    A 10.35-m-long sediment core from the Luobei depression in Lop-Nur, Xinjiang, Northwest China, provides detailed information about environmental changes during the Late Pleistocene. The samples taken every 5 cm of the core were analyzed for 10 environmental proxies, including magnetic susceptibility, granularity, chroma, carbonate and loss on ignition (LOI), and pH value. The chronology data are provided by the uranium/thorium disequilibrium dates. The sediments of the section were deposited during the last 32000 years. The results of analysis of 10 proxies were examined using multivariate statistical analysis, and the principal components were calculated. According to the results, the Late Pleistocene sequence contains four climatic and environmental stages appearing in the cycles of cold-wet and warm-dry changes. During 10-9 ka BP, it was the earliest warm episode in the Holocene. Environmental changes in this district were restricted by global change, as suggested by the analysis of glacial-interglacial cycles. But it was different from the mutative trend of a monsoon region in East China because of its own characteristics, which was the situation of cold-wet and warm-dry climate-environment change. The candidate reason may be the uplift of the Tibet Plateau and the westerly wind circulation. ?? Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH 2008.

  20. Production of Nurr-1 Specific Polyclonal Antibodies Free of Cross-reactivity Against Its Close Homologs, Nor1 and Nur77.

    PubMed

    Leblanc, Pierre; Moon, Minho; Kim, Woori; Jeong, Inhye; Kim, Chun-Hyung; Kim, Kwang-Soo

    2015-08-17

    The nuclear receptor subfamily 4 (NR4A) is composed of 3 related proteins sharing a DNA binding domain (DBD) and a ligand-binding domain (LBD). The nuclear receptor related 1 protein (Nurr1 or NR4A2) plays a key role in the maintenance of the dopaminergic system. Dopamine dysfunctions associated with the Nurr1 gene include Parkinson's disease, schizophrenia and manic depression among others. Furthermore, recent evidence indicates that Nurr1 is also expressed in other brain areas such as the hippocampus and plays critical roles for learning and memory. The other members of the family are nerve growth factor IB (Nur77 or NR4A1) and neuron-derived orphan receptor 1 (NOR1 or NR4A3). To help investigate the precise functional roles of Nurr1 in dopaminergic and other brain region-related neuronal dysfunctions antibodies devoid of cross-reactivities against Nur77 and NOR1 were needed. Since the proteins are more divergent in their LBDs than in their DNA binding domains immunization with purified LBDs should yield antibodies specific for Nurr1 with minimal reactivities against Nur77 and/or NOR1. Although anti-Nurr1 antibodies were successfully generated these showed significant immunoreactivity against the other members of the family. Affinity chromatography over immobilized Protein A followed by pre-adsorption against immobilized Nur77 and NOR1 LBDs yielded Nurr1 specific antibodies free of cross-reactivity. Here, we selectively target antibodies against a specific member of a highly conserved family of proteins by immunizing animals with their most divergent regions followed by removing cross reactive antibodies by pre-adsorption. The goal of the protocol is to increase polyclonal antibodies specificity through pre-adsorption against cross-reactive antigens.

  1. Venezuelines A-G, new phenoxazine-based alkaloids and aminophenols from Streptomyces venezuelae and the regulation of gene target Nur77.

    PubMed

    Ren, Jinwei; Liu, Dong; Tian, Li; Wei, Yangye; Proksch, Peter; Zeng, Jinzhang; Lin, Wenhan

    2013-01-01

    Five new phenoxazine-based alkaloids venezuelines A-E (1-5) and two new aminophenols venezuelines F-G (6-7), as well as three known analogues exfoliazone, chandrananimycin D and carboxyexfoliazone were isolated from the fermentation broth of the marine-derived bacterium Streptomyces venezuelae. The structures of new compounds were determined on the basis of extensive spectroscopic analysis. The cytotoxic activity of these compounds against a panel of tumor cell lines were tested, while the regulation of gene target Nur77 of 2 and exfoliazone (8) were evaluated.

  2. Seismites in slowly deforming regions - evidence for diffuse seismicity in the northern Ejina Basin (Gaxun Nur Basin)

    NASA Astrophysics Data System (ADS)

    Rudersdorf, Andreas; Hartmann, Kai; Reicherter, Klaus

    2014-05-01

    Past earthquakes leave various types of evidence on the Earth's surface. Seismic waves in water-saturated sediments lead to the deformation of original bedding, unconformities and event layers. The term "seismite" was introduced to describe the various co-seismic effects of earthquakes on sediments that range from principally brittle deformation (e.g., neptunian dykes, hydrofracturing) to soft-sediment deformation (e.g., liquefaction, convolution, seismoslumps). The Gobi belt of left-lateral transpression between the active deformation zones of the Tibetan Plateau - driven by the India-Eurasian continental collision, and the Gobi-Altai mountain ranges - showing large-scale faulting as far-field responses of above-named collision, exhibits large and remote desert environments with rugged and low topography that are overprinted by strong eolian erosion by competing wind systems. The Ejina Basin (Gaxun Nur Basin, Inner Mongolia) has been extensively studied and shows evidence for neotectonic faulting (indirectly dated by affected lacustrine sediments) through detected lineaments, morphotectonic investigation and geophysical reconnaissance. The instrumental seismicity is low. Different modes of faulting are discussed, with both WSW-ENE and conjugate trending strike-slip faulting with associated pull-apart basins, as well as far-field-induced NW-SE trending thrusts, being found. The basin is a huge endorheic delta built by the Hei River (chin. Heihe, mong. Ruoshui) and comprises Quaternary sedimentary successions up to 300 m in thickness, which overlie Neogene and Mesozoic sedimentary bedrock. The Quaternary sedimentary successions consist of changing intercalations of eolian and fluvial sands, lacustrine silts and clays and playa evaporites. Positive landforms, such as yardangs (wind-sculpted clay terraces) in the lower reaches of the Hei River (northern Ejina Basin) serve as valuable outcrops for paleoseismic investigation. They exhibit units of deformed sediments

  3. Selective ligand activity at Nur/retinoid X receptor complexes revealed by dimer-specific bioluminescence resonance energy transfer-based sensors

    PubMed Central

    Giner, Xavier C; Cotnoir-White, David; Mader, Sylvie; Lévesque, Daniel

    2017-01-01

    Retinoid X receptors (RXR) play a role as master regulators due to their capacity to form heterodimers with other nuclear receptors. Accordingly, retinoid signaling is involved in multiple biological processes, including development, cell differentiation, metabolism and cell death. However, the role and functions of RXR in different heterodimer complexes remain unsolved, mainly because most RXR drugs (called rexinoids) are not selective to specific heterodimer complexes. This also strongly limits the use of rexinoids for specific therapeutic approaches. In order to better characterize rexinoids at specific nuclear receptor complexes, we have developed and optimized luciferase protein complementation-based Bioluminescence Resonance Energy Transfer (BRET) assays, which can directly measure recruitment of a co-activator motif fused to yellow fluorescent protein (YFP) by specific nuclear receptor dimers. To validate the assays, we compared rexinoid modulation of co-activator recruitment by RXR homodimer, and heterodimers Nur77/RXR and Nurr1/RXR. Results reveal that some rexinoids display selective co-activator recruitment activities with homo- or hetero-dimer complexes. In particular, SR11237 (BMS649) has increased potency for recruitment of co-activator motif and transcriptional activity with the Nur77/RXR heterodimer compared to other complexes. This technology should prove useful to identify new compounds with specificity for individual dimeric species formed by nuclear receptors. PMID:26148973

  4. Involvement of NAK-1, the human nur77 homologue, in surface IgM-mediated apoptosis in Burkitt lymphoma cell line BL41.

    PubMed

    Mapara, M Y; Weinmann, P; Bommert, K; Daniel, P T; Bargou, R; Dörken, B

    1995-09-01

    The induction of apoptosis via surface IgM (sIgM) in immature B cells requires de novo transcription. To investigate the regulation of activation-induced cell death (AICD) in B cells we used a cell line model consisting of an Epstein-Barr virus-negative Burkitt lymphoma cell line (BL41), which is highly sensitive, and a subclone which is resistant to sIgM-mediated apoptosis (BL41/B5). Resistance in this cell line was not due to down-regulation of sIgM or functional impairment in signal transduction of the surface Ig complex. The zinc finger transcription factor nur77 has been implicated to play an important role in CD3-mediated apoptosis in murine T cells. We were able to demonstrate that surface IgM ligation and subsequent apoptosis in BL41 cells is associated with a concomitant induction of NAK-1, the human nur77 homologue. Induction of NAK-1 mRNA and DNA binding activity in the nucleus could be readily observed by means of Northern blot and electrophoretic mobility shift assay, respectively. In contrast, the resistant clone BL41/B5 did not show any NAK-1 expression upon stimulation. This suggests a role for NAK-1 in sIgM-mediated apoptosis of immature B cells.

  5. Tonic LAT-HDAC7 Signals Sustain Nur77 and Irf4 Expression to Tune Naive CD4 T Cells.

    PubMed

    Myers, Darienne R; Lau, Tannia; Markegard, Evan; Lim, Hyung W; Kasler, Herbert; Zhu, Minghua; Barczak, Andrea; Huizar, John P; Zikherman, Julie; Erle, David J; Zhang, Weiguo; Verdin, Eric; Roose, Jeroen P

    2017-05-23

    CD4(+) T cells differentiate into T helper cell subsets in feedforward manners with synergistic signals from the T cell receptor (TCR), cytokines, and lineage-specific transcription factors. Naive CD4(+) T cells avoid spontaneous engagement of feedforward mechanisms but retain a prepared state. T cells lacking the adaptor molecule LAT demonstrate impaired TCR-induced signals yet cause a spontaneous lymphoproliferative T helper 2 (TH2) cell syndrome in mice. Thus, LAT constitutes an unexplained maintenance cue. Here, we demonstrate that tonic signals through LAT constitutively export the repressor HDAC7 from the nucleus of CD4(+) T cells. Without such tonic signals, HDAC7 target genes Nur77 and Irf4 are repressed. We reveal that Nur77 suppresses CD4(+) T cell proliferation and uncover a suppressive role for Irf4 in TH2 polarization; halving Irf4 gene-dosage leads to increases in GATA3(+) and IL-4(+) cells. Our studies reveal that naive CD4(+) T cells are dynamically tuned by tonic LAT-HDAC7 signals. Published by Elsevier Inc.

  6. Mercaptursäure und Nukleosidaddukt im Harn als Biomarker in 1-Hydroxymethylpyren-exponierten Ratten

    NASA Astrophysics Data System (ADS)

    Ma, Lan

    2002-01-01

    1-Methylpyren (MP) ist hepatokanzerogen in neugeborenen männlichen Mäusen. Durch Hydroxylierung an der benzylischen Stelle und anschließende Sulfonierung wird MP zu DNA-reaktivem 1-Sulfooxymethylpyren (SMP) aktiviert. In der Ratte führt die Exposition des benzylischen Alkohols, 1-Hydroxymethylpyren (HMP), zur DNA-Adduktbildung in verschiedenen Geweben. Eventuelle Konsequenz der Toxifizierung ist die Ausscheidung entsprechender Mercaptursäure und Nukleosidaddukt im Harn, welche aufgrund ihrer Herkunft als Biomarker eignen könnten. In dieser Arbeit wird die Ausscheidung der Mercaptursäure und des N2-Desoxyguanosinadduktes in HMP-exponierten Ratten untersucht. Nach der Applikation von HMP bzw. MP wurden weniger als 1 % der Dosis als MPMA über Urin und Faeces ausgeschieden (0 - 48 h). Die Ausscheidung erfolgt hauptsächlich in den ersten 24 h nach der Applikation. MPdG konnte weder in Urin noch in Faeces der HMP-behandelten Tieren identifiziert werden. Nach direkter SMP-Applikation wurde MPdG nur in sehr geringe Menge (weniger als 0,9 ppm in 12 h) im Urin gefunden. Aufgrund der geringen Menge eignet sich MPdG nicht als Biomarker. MPMA dagegen, lässt sich analytisch gut erfassen. Es sollte daher untersucht werden, ob MPMA die Toxifizierung des HMP wiederspiegelt. Die Voraussetzung dafür ist die Kenntnisse über das Metabolismusmuster von HMP. Es wurde daher umfassende Untersuchungen zum Metabolismus des HMP durchgeführt. Die Ergebnisse zeigten, dass mehr als 80 % der Metaboiten in ihrer oxidierten Form (PCS, deren Glucuronsäure-Konjugate sowie phenolische Sulfatester der PCS) ausgeschieden wurden. Demnach spielt die Oxidation des HMP zu PCS eine sehr wichtige Rolle bei der Detoxifizierung und Ausscheidung von HMP. Ferne konnte nachgewiesen werden, dass die Enzyme Alkohol- und Aldehyd-Dehydrogenase an der Oxidation von HMP beteiligt waren. Die Inhibitoren Disulfiram und Ethanol der o. g. Enzyme wurde daher zur Modulation der Detoxifizierung in vivo eingesetzt

  7. Diagnosing ALS

    MedlinePlus

    ... that a person diagnosed with ALS seek a second opinion from an ALS "expert" - someone who diagnoses and treats many ALS patients and has training in this medical specialty. The ALS Association maintains a list of recognized experts in the field of ALS. See ALS Association Certified Centers of ...

  8. Holocene environments and climate in the Mongolian Altai reconstructed from the Hoton-Nur pollen and diatom records: a step towards better understanding climate dynamics in Central Asia

    NASA Astrophysics Data System (ADS)

    Rudaya, Natalia; Tarasov, Pavel; Dorofeyuk, Nadezhda; Solovieva, Nadia; Kalugin, Ivan; Andreev, Andrei; Daryin, Andrei; Diekmann, Bernhard; Riedel, Frank; Tserendash, Narantsetseg; Wagner, Mayke

    2009-03-01

    This study presents the results of the palynological and diatom analyses of the sediment core recovered in Hoton-Nur Lake (48°37'18″N, 88°20'45″E, 2083 m) in 2004. Quantitative reconstruction of the Holocene vegetation and climate dynamics in the semiarid Mongolian Altai suggests that boreal woodland replaced the primarily open landscape of northwestern Mongolia at about 10 kyr BP (1 kyr = 1000 cal yr) in response to a noticeable increase in precipitation from 200-250 mm/yr to 450-550 mm/yr. A decline of the forest vegetation and a return to a predominance of open vegetation types occurred after 5 kyr BP when precipitation sums decreased to 250-300 mm/yr. Prior to 11.5 kyr BP diatom concentrations are relatively low and the lake is dominated by planktonic Cyclotella and small Fragilariaceae, suggesting the existence of a relatively deep and oligotrophic/mesotrophic lake. The great abundance of Staurosirella pinnata from the beginning of the record until 10.7 kyr BP might imply intensified erosion processes in the catchment and this is fully consistent with the presence of scarce and dry vegetation and the generally arid climate during this period. From about 10.7 kyr BP, more planktonic diatom taxa appeared and increased in abundance, indicating that the lake became more productive as diatom concentration increased. This change correlates well with the development of boreal woodland in the catchment. Decrease in precipitation and changes in the vegetation towards steppe are reflected by the rapid increase in Aulacoseira distans from about 5 kyr BP. The Holocene pollen and diatom records do not indicate soil and vegetation cover disturbances by the anthropogenic activities, implying that the main transformations of the regional vegetation occurred as a result of the natural climate change. Our reconstruction is in agreement with the paleomonsoon records from China, demonstrating an abrupt strengthening of the summer monsoon at 12 kyr BP and an associated

  9. ALS Association

    MedlinePlus

    ... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

  10. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhong; Jia, Hongjuan

    2017-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  11. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhong; Jia, Hongjuan

    2016-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  12. Das Prinzip Bewegung - Herz und Gehirn als Metaphern des menschlichen Lebens

    NASA Astrophysics Data System (ADS)

    Otis, Laura

    In diesem Jahr, in dem wir Charles Darwins gedenken, möchte ich etwas riskieren und eine Frage erörtern, die für die Literatur ebenso wie für die Biologie zentral ist: Was ist das Leben? Die Antwort auf diese Frage finden wir nicht in der Bibliothek und nicht im Labor, zumindest nicht an diesen erkenntnisproduzierenden Stellen allein. Als Literaturwissenschaftlerin und ehemalige Naturwissenschaftlerin glaube ich, dass wir das Leben nur verstehen werden, wenn wir seinen Wirkungen überall nachforschen, inklusive in der Literatur.

  13. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- www.mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) ...

  14. Ludwig Boltzmann als Experimentalphysiker: Frühe Bestätigung der Maxwell-Theorie

    NASA Astrophysics Data System (ADS)

    Rumpf, Klemens; Granitzer, Petra

    2006-09-01

    Am Beispiel von Boltzmanns Experimenten zur Bestätigung der Maxwell-Theorie wird dessen hervorragende Begabung auch als Experimentalphysiker deutlich. Die dargestellten Arbeiten fanden etwa 15 Jahre vor den Hertzschen Experimenten statt, zu einem Zeitpunkt also, als die noch junge Maxwell-Theorie dringend experimenteller Bestätigung bedurfte. Boltzmann konnte mit seinen experimentellen Untersuchungen eine direkte Konsequenz der Maxwellschen elektromagnetischen Theorie, die so genannte Maxwell-Relation, bestätigen. Seine Experimente stellten nicht nur lange Zeit den stärksten Beleg für die Richtigkeit der Maxwellschen Lichttheorie dar, sondern waren eine experimentelle Spitzenleistung an der Grenze des damals Möglichen. Besonders Boltzmanns Bestimmung der Dielektrizitätskonstanten von Gasen fand noch Jahrzehnte später Erwähnung in namhaften Lehrbüchern.

  15. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  16. A Dietary Medium-Chain Fatty Acid, Decanoic Acid, Inhibits Recruitment of Nur77 to the HSD3B2 Promoter In Vitro and Reverses Endocrine and Metabolic Abnormalities in a Rat Model of Polycystic Ovary Syndrome.

    PubMed

    Lee, Bao Hui; Indran, Inthrani Raja; Tan, Huey Min; Li, Yu; Zhang, Zhiwei; Li, Jun; Yong, Eu-Leong

    2016-01-01

    Hyperandrogenism is the central feature of polycystic ovary syndrome (PCOS). Due to the intricate relationship between hyperandrogenism and insulin resistance in PCOS, 50%-70% of these patients also present with hyperinsulinemia. Metformin, an insulin sensitizer, has been used to reduce insulin resistance and improve fertility in women with PCOS. In previous work, we have noted that a dietary medium-chain fatty acid, decanoic acid (DA), improves glucose tolerance and lipid profile in a mouse model of diabetes. Here, we report for the first time that DA, like metformin, inhibits androgen biosynthesis in NCI-H295R steroidogenic cells by regulating the enzyme 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase type 2 (HSD3B2). The inhibitory effect on HSD3B2 and androgen production required cAMP stimulation, suggesting a mechanistic action via the cAMP-stimulated pathway. Specifically, both DA and metformin reduced cAMP-enhanced recruitment of the orphan nuclear receptor Nur77 to the HSD3B2 promoter, coupled with decreased transcription and protein expression of HSD3B2. In a letrozole-induced PCOS rat model, treatment with DA or metformin reduced serum-free testosterone, lowered fasting insulin, and restored estrous cyclicity. In addition, DA treatment lowered serum total testosterone and decreased HSD3B2 protein expression in the adrenals and ovaries. We conclude that DA inhibits androgen biosynthesis via mechanisms resulting in the suppression of HSD3B2 expression, an effect consistently observed both in vitro and in vivo. The efficacy of DA in reversing the endocrine and metabolic abnormalities of the letrozole-induced PCOS rat model are promising, raising the possibility that diets including DA could be beneficial for the management of both hyperandrogenism and insulin resistance in PCOS.

  17. A new approach for reconstruction of the Holocene climate in the Mongolian Altai: The high-resolution δ13C records of TOC and pollen complexes in Hoton-Nur Lake sediments

    NASA Astrophysics Data System (ADS)

    Rudaya, Natalia; Li, Hong-Chun

    2013-06-01

    δ13C of total organic carbon (TOC) and pollen grain, TOC, C/N ratio, and δ15N of total organic nitrogen (TON) in a 2.57-m long core from Hoton-Nur Lake in Mongolian Altai have been measured for reconstruction of the Holocene climates. The δ13C values of TOC and pollen carbon have similar average values but different ranges. Pollen δ13C has negative correlation with %AP (arboreal taxa pollen) and positive correlation with %NAP (herbaceous pollen and spores) that are connected with conditions of humidity in the area. Taiga-biome has lighter δ13C than steppe-biome. Hence, pollen δ13C composition is more sensitive to changes of humidity in the analogous spectra than palynotaxonomical structure and δ13C of TOC. Based on our results, the Holocene climates in Mongolian Altai are: (1) dry conditions prior to 11.5 kyr BP; (2) wet conditions between 11.5 and 6.0 kyr BP; (3) a relatively dry/cool episode during 6-4 kyr BP; (4) stable cool and semiarid conditions with moderately effective moisture during the past 4000 years. Two abrupt climatic changes occurred at ˜7.45 kyr BP and ˜11.5 kyr BP might be related to glacial activities. The Holocene climatic trend in Mongolian Altai which is controlled by the Westerlies is similar to the trend of monsoonal climate shown by the Chinese speleothem records as well as the lake/sand dune evidence in the deserts of NW China. The contact of the two climatic systems and shift of the monsoonal boundary during the past need to be further studied.

  18. Induction of apoptosis in PA-1 ovarian cancer cells by vitamin K2 is associated with an increase in the level of TR3/Nur77 and its accumulation in mitochondria and nuclei.

    PubMed

    Sibayama-Imazu, Toshiko; Fujisawa, Yukari; Masuda, Yutaka; Aiuchi, Toshihiro; Nakajo, Shigeo; Itabe, Hiroyuki; Nakaya, Kazuyasu

    2008-07-01

    We examined the growth-inhibitory and apoptosis-inducing effects of vitamin K(2) (VK(2); menaquinone-4) on various lines of human ovarian cancer cells to study the mechanism of induction of apoptosis by VK(2). Cell proliferation was determined by XTT method, and apoptotic cells were detected by Hoechst staining. TR3, also known as Nur77 and NGFI-B, was detected by immunoblotting and immunofluorescence analysis. Role of TR3 on induction of apoptosis was examined by a siRNA experiment. We found that PA-1 cells were the most sensitive to VK(2) (IC(50) = 5.0 +/- 0.7 microM), while SK-OV-3 cells were resistant to VK(2). Immunoblotting and immunofluorescence analyses indicated that levels of TR3 were elevated in cell lysates 48 h after the start of treatment with 30 microM VK(2). In the VK(2)-treated cells, TR3 accumulated at significant levels in mitochondria, as well as in the nuclei of PA-1 cells. No similar changes were observed in SK-OV-3 cells under the same conditions. Treatment of PA-1 cells with small interfering RNA (siRNA) directed against TR3, and with cycloheximide or SP600125 (an inhibitor of c-jun N-terminal kinase; JNK), separately, inhibited the VK(2)-induced synthesis of TR3 and apoptosis. From these results, we can conclude that an increase in the synthesis of TR3 and the accumulation of TR3 in mitochondria and in nuclei might be involved in the induction of apoptosis by VK(2) and that the synthesis of TR3 might be regulated through a JNK signaling pathway.

  19. Einführung in die Renaturierungsökologie

    NASA Astrophysics Data System (ADS)

    Zerbe, Stefan; Wiegleb, Gerhard; Rosenthal, Gert

    Durch die übernutzung der Naturressourcen sind heute weltweit viele natürliche wie auch durch Kultur entstandene ökosysteme und Landschaften in ihren Funktionen und Leistungen stark beeinträchtigt oder sogar völlig zerstört. Bereits vor mehr als einem Jahrzehnt konstatierte (1995), dass ca. 45 % der terrestrischen Landoberfläche nur eine reduzierte Kapazität für die zukünftige Landnutzung haben. Als Grund hob er eine in der Vergangenheit nicht nachhaltige Landbewirtschaftung hervor. Mit einer gezielten Renaturierung der betroffenen ökosysteme soll dieser Trend umgekehrt werden (Harris und van Diggelen 2006). Vor diesem Hintergrund ist die ökosystemrenaturierung (ecological restoration) wichtiger Bestandteil der Planungs- und Naturschutzpraxis in Mitteleuropa und die Renaturierungsökologie (restoration ecology) zu einer eigenen wissenschaftlichen Arbeitsrichtung geworden.

  20. Abu al-Layth al-Libi

    DTIC Science & Technology

    2015-02-01

    jihadi doctrine, al-Libi enrolled himself in the recently erected and highly popular al-Faruq 2 “Al-Sahab Releases ‘Winds of Paradise , Part III...February 2008, http://news.bbc.co.uk/2/hi/south_asia/7220823.stm. 3 “Al-Sahab Releases ‘Winds of Paradise , Part III,’” Global Terrorism Research Project...5 “Al-Sahab Releases ‘Winds of Paradise , Part III,’” Global Terrorism Research Project. 6 Ibid. The date provided in the video is 1410

  1. What Is ALS?

    MedlinePlus

    ... Javits, actor David Niven, “Sesame Street” creator Jon Stone, boxing champion Ezzard Charles, NBA Hall of Fame ... Help for People with ALS and Caregivers Read stories from families living with ALS Forms of ALS ...

  2. Darwin, Engels und die Rolle der Arbeit in der biologischen und kulturellen Evolution des Menschen

    NASA Astrophysics Data System (ADS)

    Reichholf, Josef H.

    Im Jahre 1876, 5 Jahre nach Erscheinen von Darwins Buch über die Evolution des Menschen und die sexuelle Selektion (Darwin 1871), veröffentlichte Friedrich Engels den berühmt gewordenen Essay "Anteil der Arbeit an der Menschwerdung des Affen“ (Engels 1876). Die Kernfrage darin lautet in Kurzform: Warum hat der Mensch eigentlich ein Bedürfnis nach Arbeit? Engels Antwort wird nachfolgend näher betrachtet und vom gegenwärtigen Kenntnisstand aus beurteilt. Wie sich zeigen wird, beantworten seine Überlegungen die Frage nicht wirklich. Sie ist weiterhin offen. Es können lediglich einige zusätzliche Anhaltspunkte zur Diskussion gestellt werden. Angesichts des drängenden Problems millionenfacher Arbeitslosigkeit und der Forderungen nach einem "Grundrecht auf Arbeit“ kommt den Überlegungen zum möglichen Ursprung des Bedürfnisses nach Arbeit mehr als nur akademisches Interesse zu.

  3. Mit Mathematik zu Mehr Intelligenz in der Logistik

    NASA Astrophysics Data System (ADS)

    Möhring, Rolf H.; Schenk, Michael

    Die Lösung logistischer Probleme ist ein wichtiger Aspekt menschlichen Handelns seit Menschen gemeinsam zielgerichtet tätig wurden. Die Grundlagen dessen, was wir heute Logistik nennen, entstammen dem militärischen Bereich. So basierte z. B. das römische Imperium in starkem Maße auf militärisch-logistischen Glanzleistungen. Ob damals bereits mathematische Überlegungen eine Rolle spielten, wissen wir heute nicht. Jedoch versuchte z. B. Napoleon, der mit den bedeutendsten Mathematikern seiner Zeit befreundet war, den Transport seiner Truppen und die Verbreitung von Informationen zu optimieren und strategisch einzusetzen.1,2

  4. /Cu-Al System

    NASA Astrophysics Data System (ADS)

    Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum

    2014-05-01

    Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

  5. ALS (Amyotrophic Lateral Sclerosis)

    MedlinePlus

    ... risk factors for veterans include exposure to lead, pesticides, and other environmental toxins. ALS is recognized as ... from scientific studies suggests that both genetics and environment play a role in the development of ALS. ...

  6. Lou Gehrig's Disease (ALS)

    MedlinePlus

    ... 1930s. People in England and Australia call ALS motor neurone disease (MND). The French refer to it ... about ALS in 1869. Lou Gehrig's disease damages motor neurons in the brain and spinal cord. Motor ...

  7. Genetic testing in ALS

    PubMed Central

    McLaughlin, Russell L.; Heverin, Mark; Thorpe, Owen; Abrahams, Sharon; Al-Chalabi, Ammar; Hardiman, Orla

    2017-01-01

    Objective: To determine the degree of consensus among clinicians on the clinical use of genetic testing in amyotrophic lateral sclerosis (ALS) and the factors that determine decision-making. Methods: ALS researchers worldwide were invited to participate in a detailed online survey to determine their attitudes and practices relating to genetic testing. Results: Responses from 167 clinicians from 21 different countries were analyzed. The majority of respondents (73.3%) do not consider that there is a consensus definition of familial ALS (FALS). Fifty-seven percent consider a family history of frontotemporal dementia and 48.5% the presence of a known ALS genetic mutation as sufficient for a diagnosis of FALS. Most respondents (90.2%) offer genetic testing to patients they define as having FALS and 49.4% to patients with sporadic ALS. Four main genes (SOD1, C9orf72, TARDBP, and FUS) are commonly tested. A total of 55.2% of respondents would seek genetic testing if they had personally received a diagnosis of ALS. Forty-two percent never offer presymptomatic testing to family members of patients with FALS. Responses varied between ALS specialists and nonspecialists and based on the number of new patients seen per year. Conclusions: There is a lack of consensus among clinicians as to the definition of FALS. Substantial variation exists in attitude and practices related to genetic testing of patients and presymptomatic testing of their relatives across geographic regions and between experienced specialists in ALS and nonspecialists. PMID:28159885

  8. Ventilatory Control in ALS

    PubMed Central

    Nichols, Nicole L.; Van Dyke, J.; Nashold, L.; Satriotomo, I.; Suzuki, M.; Mitchell, G.S.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease. ALS selectively causes degeneration in upper and lower (spinal) motor neurons, leading to muscle weakness, paralysis and death by ventilatory failure. Although ventilatory failure is generally the cause of death in ALS, little is known concerning the impact of this disorder on respiratory motor neurons, the consequences of respiratory motor neuron cell death, or the ability of the respiratory control system to “fight back” via mechanisms of compensatory respiratory plasticity. Here we review known effects of ALS on breathing, including possible effects on rhythm generation, respiratory motor neurons, and their target organs: the respiratory muscles. We consider evidence for spontaneous compensatory plasticity, preserving breathing well into disease progression despite dramatic loss of spinal respiratory motor neurons. Finally, we review current and potential therapeutic approaches directed toward preserving the capacity to breathe in ALS patients. PMID:23692930

  9. ALS2 mutations

    PubMed Central

    Schneider, Susanne A.; Carr, Lucinda; Deuschl, Guenther; Hopfner, Franziska; Stamelou, Maria; Wood, Nicholas W.; Bhatia, Kailash P.

    2014-01-01

    Objective: To determine the genetic etiology in 2 consanguineous families who presented a novel phenotype of autosomal recessive juvenile amyotrophic lateral sclerosis associated with generalized dystonia. Methods: A combination of homozygosity mapping and whole-exome sequencing in the first family and Sanger sequencing of candidate genes in the second family were used. Results: Both families were found to have homozygous loss-of-function mutations in the amyotrophic lateral sclerosis 2 (juvenile) (ALS2) gene. Conclusions: We report generalized dystonia and cerebellar signs in association with ALS2-related disease. We suggest that the ALS2 gene should be screened for mutations in patients who present with a similar phenotype. PMID:24562058

  10. Initial Symptoms of ALS

    MedlinePlus

    ... Combine your passion and commitment to finding a cure for ALS while achieving physical challenges through athletic events Register ... - 1275 K Street NW - Suite 250 - Washington, DC 20005 All content and works posted on this website are owned ...

  11. Genetic Testing for ALS

    MedlinePlus

    ... Some medical centers may require a neurological exam, psychological assessment and counseling before predictive testing. If a person in the family with ALS has a negative genetic test result (no identified genetic mutation), testing family members ...

  12. Lou Gehrig's Disease (ALS)

    MedlinePlus

    ... when it becomes necessary. For instance, a power wheelchair can enable a paralyzed person with ALS to ... done these things despite being confined to a wheelchair for many years, being able to move only ...

  13. Rub al Khali, Arabia

    NASA Image and Video Library

    2008-08-08

    NASA Terra spacecraft shows the Rub al Khali, one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula; it includes parts of Oman, United Arab Emirates, and Yemen.

  14. Ag-Al-Ca

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Ag-Al-Ca' with the content:

  15. Frequently Asked Questions about ALS and the ALS Registry

    MedlinePlus

    ... long do people with familial ALS live? Do clusters of ALS possibly exist? (I have been told ... related?) What are the problems with studying possible clusters of ALS? What are motor neuron (nerve cell) ...

  16. Epidemiology of ALS.

    PubMed

    Nelson, L M

    Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder of unknown etiology. ALS onset is rare before age 40 and increases with age thereafter. Men are at higher risk than women (ratio 1.3:1). Other than age and gender, the only indisputable risk factor for ALS is genetic susceptibility, with familial cases occurring in about 10% of most case series. Genetic linkage studies have provided evidence that a mutant form of the gene that codes for Cu/Zn superoxide dismutase, an endogenous free radical scavenger, is important in 15-20% of familial cases. Epidemiologic studies have identified associations of sporadic ALS with work in occupations that involve toxicant exposure. Environmental toxicants may act against a background of increased genetic susceptibility; however, genetically acquired biochemical defects have not been identified in sporadic ALS patients. Other epidemiologic theories of disease etiology have emphasized the potential role of physical trauma, electrical shock, and vigorous physical exertion, but evidence regarding these factors is inconsistent.

  17. Statins: Do They Cause ALS?

    MedlinePlus

    Statins: Do they cause ALS? Do statins cause amyotrophic lateral sclerosis (ALS)? Answers from Francisco Lopez-Jimenez, M.D. ... D. References Sorensen HT, et al. Statins and amyotrophic lateral sclerosis: The level of evidence for an association. Journal ...

  18. Photoelectron spectroscopy of the aluminum hydride anions: AlH2-, AlH3-, Al2H6-, Al3H9-, and Al4H12-

    NASA Astrophysics Data System (ADS)

    Zhang, Xinxing; Wang, Haopeng; Collins, Evan; Lim, Alane; Ganteför, Gerd; Kiran, Boggavarapu; Schnöckel, Hansgeorg; Eichhorn, Bryan; Bowen, Kit

    2013-03-01

    We report measurements of the negative ion photoelectron spectra of the simple aluminum hydride anions: AlH2-, AlH3-, Al2H6-, Al3H9-, and Al4H12-. From these spectra, we measured the vertical detachment energies of the anions, and we estimated the electron affinities of their neutral counterparts. Our results for AlH2-, AlH3-, and Al2H6- were also compared with previous predictions by theory.

  19. Photoelectron spectroscopy of the aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-).

    PubMed

    Zhang, Xinxing; Wang, Haopeng; Collins, Evan; Lim, Alane; Ganteför, Gerd; Kiran, Boggavarapu; Schnöckel, Hansgeorg; Eichhorn, Bryan; Bowen, Kit

    2013-03-28

    We report measurements of the negative ion photoelectron spectra of the simple aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-). From these spectra, we measured the vertical detachment energies of the anions, and we estimated the electron affinities of their neutral counterparts. Our results for AlH2(-), AlH3(-), and Al2H6(-) were also compared with previous predictions by theory.

  20. ALS superbend magnet system

    SciTech Connect

    Zbasnik, J.; Wang, S.T.; Chen, J.Y.; DeVries, G.J.; DeMarco, R.; Fahmie, M.; Geyer, A.; Green, M.A.; Harkins, J.; Henderson, T.; Hinkson, J.; Hoyer, E.H.; Krupnick, J.; Marks, S.; Ottens, F.; Paterson, J.A.; Pipersky, P.; Portmann, G.; Robin, D.A.; Schlueter, R.D.; Steier, C.; Taylor, C.E.; Wahrer, R.

    2000-09-15

    The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refrigeration. We also present the current status of fabrication and testing.

  1. Al Shanker Remembers.

    ERIC Educational Resources Information Center

    American Educator, 2000

    2000-01-01

    In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

  2. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Integrated Risk Information System ( IRIS ) Chemical Assessment Summary U.S . Environmental Protection Agency National Center for Environmental Assessment This IRIS Summary has been removed from the IRIS database and is available for historical reference purposes . ( July 2016 ) Fosetyl - al ; CASRN

  3. Proton irradiation studies on Al and Al5083 alloy

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, P.; Gayathri, N.; Bhattacharya, M.; Gupta, A. Dutta; Sarkar, Apu; Dhar, S.; Mitra, M. K.; Mukherjee, P.

    2017-10-01

    The change in the microstructural parameters and microhardness values in 6.5 MeV proton irradiated pure Al and Al5083 alloy samples have been evaluated using different model based techniques of X-ray diffraction Line Profile Analysis (XRD) and microindendation techniques. The detailed line profile analysis of the XRD data showed that the domain size increases and saturates with irradiation dose both in the case of Al and Al5083 alloy. The corresponding microstrain values did not show any change with irradiation dose in the case of the pure Al but showed an increase at higher irradiation doses in the case of Al5083 alloy. The microindendation results showed that unirradiated Al5083 alloy has higher hardness value compared to that of unirradiated pure Al. The hardness increased marginally with irradiation dose in the case of Al5083, whereas for pure Al, there was no significant change with dose.

  4. Al Sumelat Water Network. Village of Al Sumelat, Iraq

    DTIC Science & Technology

    2006-03-15

    OFFICE OF THE SPECIAL INSPECTOR GENERAL FOR IRAQ RECONSTRUCTION AL SUMELAT WATER NETWORK VILLAGE OF AL SUMELAT, IRAQ...Sumelat Water Network Village of Al Sumelat, Iraq 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Al Sumelat Water Network Village of Al Sumelat, Iraq Synopsis Introduction. This report was previously provided on a limited distribution basis

  5. ALS insertion devices

    NASA Astrophysics Data System (ADS)

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W. V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1991-08-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system.

  6. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  7. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  8. AL Amyloidosis and Agent Orange

    MedlinePlus

    ... for survivors' benefits . Research on AL amyloidosis and herbicides The Health and Medicine Division (formally known as ... to the compounds of interest found in the herbicide Agent Orange and AL amyloidosis." VA made a ...

  9. Al Qaeda as a System

    DTIC Science & Technology

    2006-03-15

    either as welcome guests or parasites . As welcome guests, Al Qaeda members take sanctuary in sponsor states. Sponsor states provide Al Qaeda with...sponsorship, Al Qaeda takes sanctuary as parasites either overtly or covertly. They take overt sanctuary in countries that publicly claim a policy...39 Yehudit Barsky, “Al Qa’ida, Iran, and Hezbollah: A Continuing Symbiosis ,” The American Jewish Committee Series on Terrorism , February 2004, 2-3

  10. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  11. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    NASA Astrophysics Data System (ADS)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  12. Submicron Nb-Al/Al oxide-Nb tunnel junctions sandwiched between Al films

    NASA Astrophysics Data System (ADS)

    Maier, D.; Rothermel, H.; Gundlach, K. H.; Zimmermann, R.

    1996-02-01

    A process has been developed to embed Nb-Al/Al oxide-Nb junctions in planar structures of Al films. The submicron junctions are defined by photoresist lines. Motivation for this effort is a possible application of Nb junctions confined between normal conducting Al films as mixers above 700 GHz where Nb films loose their superconductive properties and tuning circuits made out of Nb therefore exhibit losses. First mixer results at 816 GHz are presented.

  13. Growth and Optical Properties of Al rich AlN/AlGaN Quantum Wells

    NASA Astrophysics Data System (ADS)

    Tahtamouni, T. M. Al; Nepal, N.; Nakarmi, M. L.; Lin, J. Y.; Jiang, H. X.

    2006-03-01

    Al rich AlGaN alloys are promising materials for the applications in the optoelectronic devices such as deep ultraviolet (UV) emitters and detectors in the spectral range down to 200 nm. AlGaN based UV emitters (λ<340nm) has applications in bio-chemical agent detection and medical research/ health care. To realize deep UV emission (λ< 280 nm) Al rich AlGaN based quantum wells (QWs) are required. We report here the growth of AlN/AlxGa1-xNQWs (x>0.65) on AlN/sapphire templates by metalorganic chemical vapor deposition (MOCVD). Deep UV photoluminescence (PL) was employed to study the optical properties of the QWs. Well width (Al composition) dependence was studied by varying the QW thickness (Al composition) with fixed x ˜ 0.65 (well width at 3 nm). Optical properties of these QWs such as the effects of alloy fluctuation, temperature, strain and piezoelectric field, carrier and exciton localizations on the quantum efficiency have been studied. Carrier and exciton dynamics were probed. Implications of our findings on the applications of Al rich AlN/AlGaN QWs for UV emitters and detectors will also be discussed.

  14. Studies of 27Al NMR in SrAl4

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Higa, Nonoka; Kuroshima, Hiroko; Toji, Tatsuki; Morishima, Mach; Minei, Motofumi; Yogi, Mamoru; Nakamura, Ai; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika; Harima, Hisatomo

    A charge density wave (CDW) transition at TCDW = 243 K and a structural phase (SP) transition at approximately 100 K occur in SrAl4 with the BaAl4-type body center tetragonal structure, which is the divalent and non-4f electron reference compound of EuAl4. To understand the behaviors of the CDW and SP transitions, the 27Al NMR measurements using a single crystal and a powder sample of SrAl4 have been carried out. The line width below TCDW is modulated by an electrical quadruple interaction between 27Al nucleus and CDW charge modulation. The incommensurate CDW state below TCDW changes into a different structure below TSP. The temperature dependences of Knight shifts of 27Al(I) and 27Al(II) show the different behaviors. The temperature variation of 27Al(I) Knight shift shows anomalies at the CDW and SP transition temperatures, revealing the shift to negative side below TCDW, which is attributable to the core polarization of the d-electrons. However, 27Al(II) Knight shift keeps almost constant except for the small shift due to the SP transition. The 1/T1T of 27Al(I) indicates the obvious changes due to the CDW and SP transitions, while that of 27Al(II) takes a constant value. The density of state at the Fermi level at Al(I) site below 60 K would be about 0.9 times less than that above TCDW.

  15. Morton et al. Reply

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  16. Morton et al. Reply

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  17. Rub' al Khali, Arabia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.

    The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  18. The Evolution of Al Qaeda

    DTIC Science & Technology

    2007-06-15

    www.carleton.ca/cciss/res_docs/itac/gendron_e.pdf; Internet. 26Muhammad Abd al-salam Faraj, Al-Farīdah al-Ghā’ibah, trans. Johannes J.G. Jansen and... Theo Van Gogh.91 Hoffman also supports the idea proposed by other experts like Benjamin Orbach and Keith Blanchard of the Congressional Research...religious intolerance over cartoons in Danish newspapers, the assassination of Theo Van Goeh, and increasing discontent among disassociated Muslim

  19. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  20. Is there a paraneoplastic ALS?

    PubMed

    Corcia, Philippe; Gordon, Paul H; Camdessanche, Jean-Philippe

    2015-06-01

    Our objective was to examine the strength of evidence in support of the paraneoplastic syndrome (PNS) as one cause of ALS and, if the association appears more likely than chance, determine which features of ALS imply concurrent malignancy. We reviewed the literature on concurrent ALS and neoplasia assessing the strength of evidence for the association. Most accounts of ALS and neoplasm are case reports or small uncontrolled series. In order of strength of evidence, three clinical situations that support a paraneoplastic aetiology for ALS are: 1) laboratory evidence of well-characterized onconeuronal antibodies, most often anti-Hu, anti-Yo or anti-Ri; 2) co-occurrence of ALS and a neoplasm known to cause PNS, usually lymphoma or cancer of the breast; and 3) combined ALS and a neoplasm not classically associated with PNS, without detectable onconeuronal antibodies. Clinical features that warrant evaluation of neoplasm include upper motor neuron disease in elderly females, rapid progression, non-motor signs, and young onset. In conclusion, most examples of ALS and neoplasm do not constitute a classically established PNS. Rare instances of elevated onconeuronal antibody titres or typical neoplasm, implies that, albeit rare, the PNS is one of a multitude of causes of ALS.

  1. Understanding ALS: new therapeutic approaches.

    PubMed

    Musarò, Antonio

    2013-09-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease associated with motor neuron degeneration, muscle atrophy and paralysis. Although numerous pathological mechanisms have been elucidated, ALS remains an invariably fatal disease in the absence of any effective therapy. The heterogeneity of the disease and the failure to develop satisfactory therapeutic protocols reinforce the view that ALS is a multi-factorial and multi-systemic disease. Thus, a better understanding of the pathogenic mechanisms and study of the potential pathological relationship between the various cellular processes is required to ensure efficacious therapy. The pathogenic mechanisms associated with ALS are reviewed, and the strengths and limitations of some new therapeutic approaches are discussed.

  2. Impurity Enhancement of Al_2O_3/Al Adhesion

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Smith, John R.; Zhang, Wenqing; Evans, Anthony

    2003-03-01

    Our first-principles computations indicate that the clean Al_2O_3/Al interface is relatively weak - weaker than bulk Al. Fracture experiments reveal that the interface is relatively strong with observed failure in bulk Al, however. This paradox is resolved via doping effects of the common impurity C. We have found that only 1/3 of a monolayer of carbon segregated to the interface can increase the work of separation by a factor of 3. The resulting strong interface is consistent with fracture experiments. It arises due to void formation in the interface, which provides low-strain sites for the carbon to segregate to. The degree of void formation is consistent with the relatively high heat of oxide formation of Al.

  3. Interfacial characterization of Al-Al thermocompression bonds

    SciTech Connect

    Malik, N.; Carvalho, P. A.; Poppe, E.; Finstad, T. G.

    2016-05-28

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO{sub 2} as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400–550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO{sub 2}. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO{sub 2}, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO{sub 2} are discussed.

  4. Climate and Conflict: A Comment on Hsiang et al.s Reply to Buhaug et al

    DTIC Science & Technology

    2014-01-01

    a wide range of climatic events, from heat waves via excess rainfall to global ENSO cycles; and a wide range of spatial scales, from municipalities...again analytical consistency; The Hsiang et al. (2011) study considers a global ENSO effect whereas the studies in the valid sample investigate a local...some of the studies described in Hsiang et al. (2013). Specifically, Buhaug et al. exclude the effects of ENSO and PDSI when estimating the aggregate

  5. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    NASA Astrophysics Data System (ADS)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-09-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  6. Explosive destruction of 26Al

    NASA Astrophysics Data System (ADS)

    Kahl, D.; Yamaguchi, H.; Shimizu, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Ge, Z.; Hayakawa, S.; Kwag, M. S.; Kim, D. H.; Moon, J. Y.; Park, S. Y.; Yang, L.

    2017-09-01

    The γ -ray emission associated with the radioactive decay of 26Al is one of the key pieces of observational evidence indicating stellar nucleosynthesis is an ongoing process in our Galaxy, and it was the first such radioactivity to be detected. Despite numerous efforts in stellar modeling, observation, nuclear theory, and nuclear experiment over the past four decades, the precise sites and origin of Galactic ^{26} Al remain elusive. We explore the present experimental knowledge concerning the destruction of ^{26} Al in massive stars. The precise stellar rates of neutron-induced reactions on ^{26} Al, such as (n,p) and (n, α , have among the largest impacts on the total ^{26} Al yield. Meanwhile, reactions involving the short-lived isomeric state of ^{26} Al such as radiative proton capture are highly-uncertain at present. Although we presented on-going experimental work from n_TOF at CERN with an ^{26} Al target, the present proceeding focuses only on the ^{26} Al isomeric radioactive beam production aspect and the first experimental results at CRIB.

  7. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    NASA Astrophysics Data System (ADS)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  8. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  9. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  10. Reply to Gopalswamy et al.

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.

    2003-01-01

    The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

  11. In memory of Al Cameron

    NASA Astrophysics Data System (ADS)

    Cowan, John; Truran, James W.

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning ele- ment formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

  12. Al-Co-Fe (030)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Co-Fe (030)' with the content:

  13. Al-La-Nb (068)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Nb (068)' with the content:

  14. Al-Cu-Zr (050)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Cu-Zr (050)' with the content:

  15. Al-La-Ni (069)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-La-Ni (069)' with the content:

  16. Al-Au-La (010)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Au-La (010)' with the content:

  17. Al-Ce-V (029)

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 1 http://dx.doi.org/10.1007/97.etType="URL"/> 'Systems from Ag-Al-Ca to Au-Pd-Si' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter 'Al-Ce-V (029)' with the content:

  18. ALS: focus on purinergic signalling.

    PubMed

    Volonté, Cinzia; Apolloni, Savina; Carrì, Maria Teresa; D'Ambrosi, Nadia

    2011-10-01

    Amyotrophic lateral sclerosis (ALS) is one of the most common neuromuscular diseases. It is devastating and fatal, causing progressive paralysis of all voluntary muscles and eventually death, while sparing cognitive functions. A pathological hallmark of ALS is neuroinflammation mediated by non-neuronal cells in the nervous system, such as microglia and astrocytes that accelerate the disease progression. Scientists have neither found a unique key mechanism, nor an effective treatment against ALS, supposedly because it is a multi-factorial and multi-systemic disease. Extracellular purines and pyrimidines are widespread and powerful physiopathological molecules, signalling to most cell types and directing cell-to-cell communication networks. They are instrumental for instance for neurotransmission, muscle contraction and immune surveillance. Recent work has reported the crucial involvement of purinergic pathways in many neurodegenerative and neuroinflammatory diseases, comprising ALS. Especially P2 receptors for ATP, P1 receptors for adenosine, and nucleotide transporters were found to be modulated in ALS cells and tissues, playing a potential role in the disease. Given the composite cellular cross-talk occurring during ALS and the established action of extracellular purines/pyrimidines as neuron-to-glia alarm signal in the nervous system, a mutual query in these two fields should now be whether, how and when purinergic would meet ALS. In this review, we will highlight the early cellular and molecular purinergic cross-talk that participates to ALS etiopathology, with the conviction that better understanding of purinergic dynamics might provide original research perspectives, stimulate alternative disease modelling, and the design and testing of more powerful targeted therapeutics against this relentlessly progressive disorder. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

  20. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K. E-mail: yadav.satyesh@gmail.com Liu, X.-Y. E-mail: yadav.satyesh@gmail.com; Wang, J.

    2016-06-14

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. The formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  1. Benefits for Military Veterans with ALS

    MedlinePlus

    ... and Caregivers Newly Diagnosed Clinical Trials Familial ALS Military Veterans For Caregivers Resources Read stories from families living with ALS ALS Registry Augmentative Communication Site Map | Press Room | FAQ | Policies | RSS | Contact ...

  2. Response to Zambon et al.

    PubMed

    Laplante, Caroline; Pollard, Thomas D

    2017-02-06

    Stimulated by our 2015 Current Biology paper [1], Zambon et al. reinvestigated how three myosin isoforms participate in the formation and constriction of the contractile ring in fission yeast. Our paper presented evidence that these myosin isoforms have distinct roles: "Conventional myosin-II Myo2 is crucial to ring assembly, unconventional myosin-II Myp2 is most important for ring constriction, and type V myosin Myo51 aids the other two myosins." Zambon et al. used different markers to reexamine the contributions of the three myosins to cytokinesis and concluded "that Myo2p is the major motor involved in ring contraction in S. pombe." Here, we show that most of the differences observed by Zambon et al. can be attributed to their use of the Rlc1p-3GFP marker, which genetically interacts with myo2-E1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. FTD and ALS: genetic ties that bind.

    PubMed

    Orr, Harry T

    2011-10-20

    Curiously, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), seemingly disparate neurodegenerative disorders, can be inherited together. Two groups (DeJesus-Hernandez et al. and Renton et al.) show that the long sought after ALS/FTD mutation on chromosomal region 9p is a hexanucleotide expansion in C90RF72. These studies, plus a study on X-linked ALS/FTD, provide molecular starting points for identifying pathways that link ALS and FTD pathogenesis.

  4. Superconductivity in Al/Al2O3 interface

    NASA Astrophysics Data System (ADS)

    Palnichenko, A. V.; Vyaselev, O. M.; Mazilkin, A. A.; Khasanov, S. S.

    2016-06-01

    Metastable superconductivity at Tc ≈ 65 K has been observed in Al foil subjected to special oxidation process, according to the ac magnetic susceptibility and electrical resistance measurements. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed during the oxidation process between metallic aluminum and its oxide.

  5. Baumard et al.'s moral markets lack market dynamics.

    PubMed

    Fessler, Daniel M T; Holbrook, Colin

    2013-02-01

    Market models are indeed indispensable to understanding the evolution of cooperation and its emotional substrates. Unfortunately, Baumard et al. eschew market thinking in stressing the supposed invariance of moral/cooperative behavior across circumstances. To the contrary, humans display contingent morality/cooperation, and these shifts are best accounted for by market models of partner choice for mutually beneficial collaboration.

  6. ALS - A unique design approach

    NASA Astrophysics Data System (ADS)

    Chamberlain, Roger A.

    1990-09-01

    An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

  7. Wadi Al Dawasir, Saudi Arabia

    NASA Image and Video Library

    2015-10-20

    In the middle of the Arabian desert the city Green Oasis Wadi Al Dawasir is being developed as a new urban center for the Wadi Al Dawasir region of Saudi Arabia, as shown in this image from NASA Terra spacecraft. Huge solar fields supply the entire city and the surrounding region with energy. Hundreds of circular agricultural fields are fed by center pivot irrigation apparatus, drawing water from subterranean aquifers. The image was acquired March 30, 2013, covers an area of 30 x 45 km, and is located at 20.2 degrees north, 44.8 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20077

  8. Al-Qaeda as Insurgency

    DTIC Science & Technology

    2005-03-18

    that directs military conduct; instead, in the words of Regis Debray “. . . the guerrilla force is the party in embryo.” Regis Debray , Revolution in...Jenkins. Deterrence and Influence in Counterterrorism: A Component in the War on al Qaeda . Santa Monica, CA: RAND, 2002. Debray , Regis . Revolution in

  9. Response to Moras et al.

    PubMed

    Rastinejad, Fraydoon; Ollendorff, Vincent; Polikarpov, Igor

    2015-06-01

    We recently reviewed full-length nuclear receptor (NR) structures in an Opinion article wherein we carefully evaluated a large body of literature. As heads of three separate laboratories working on NR architectures, we expressed our shared insights and critical comments. One group (Moras et al.) has declined to accept our strong concerns about several of their published reports. We comment on their letter.

  10. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  11. AlGaN solar-blind avalanche photodiodes with AlInN/AlGaN distributed Bragg reflectors

    NASA Astrophysics Data System (ADS)

    Yao, Chujun; Ye, Xuanchao; Sun, Rui; Yang, Guofeng; Wang, Jin; Lu, Yanan; Yan, Pengfei; Cao, Jintao

    2017-06-01

    AlGaN solar-blind avalanche photodiodes (APDs) with AlInN/AlGaN distributed Bragg reflectors (DBRs) operated at lower avalanche breakdown voltage are numerically demonstrated. The p-type AlGaN layer and the multiplicative layer with low Al composition are introduced to construct the polarization-induced electric field, which can significantly reduce the avalanche breakdown voltage of the APDs. Calculated results exhibit that the avalanche breakdown voltage of the designed APDs decrease by 13% compared with the conventional device structure. Simultaneously, an improved solar-blind spectral responsivity is achieved due to the inserted AlInN/AlGaN DBRs.

  12. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  13. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    PubMed Central

    Zhang, Kun; Li, Huan-huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-tao; Tian, Yu-feng; Yan, Shi-shen; Lin, Zhao-jun; Kang, Shi-shou; Chen, Yan-xue; Liu, Guo-lei; Mei, Liang-mo

    2015-01-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices. PMID:26387967

  14. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions.

    PubMed

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-21

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  15. AlSb/InAs/AlSb quantum wells

    NASA Technical Reports Server (NTRS)

    Kroemer, Herbert

    1990-01-01

    Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

  16. Thermal conductance of a pressed Al-Al contact

    NASA Astrophysics Data System (ADS)

    Wanner, M.

    1981-01-01

    Thermal conductance of a screw-fastened joint between two blocks of Al-alloys has been measured. An AlMg4.5Mn-block, the end of which is cooled by liquid helium, constitutes the upper part of the sample and the contact is formed at the face surface of a cylindrical extension of that block onto which a cylinder, made of AlMgSi1, is pressed by means of a copper-nickel screw. Pressing of the contact was carried out at room temperature by applying a defined torque, M, to the fastening screw. Three samples of the same shape but with differently treated surfaces of contact (machined flat, electro-chemically polished, with gold plated contacts) were studied. The results showed that the machined flat surfaces yield the best contact and that the contact conductance (measured in the range 4.2 K to 1.8 K) of all samples increased with increasing torque. In addition to thermal measurements, a study of the electrical conductance would be very interesting to determine the different contributions of phonon and electron heat conduction by means of the Wiedemann-Franz law. The work is useful for the GIRL (German Infra-Red Laboratory) space experiment.

  17. Effect of interface geometry on electron tunnelling in Al/Al2O3/Al junctions

    NASA Astrophysics Data System (ADS)

    Koberidze, M.; Feshchenko, A. V.; Puska, M. J.; Nieminen, R. M.; Pekola, J. P.

    2016-04-01

    We investigate how different interface geometries of an Al/Al2O3 junction, a common component of modern tunnel devices, affect electron transport through the tunnel barrier. We study six distinct Al/Al2O3 interfaces which differ in stacking sequences of the metal and the oxide surface atoms and the oxide termination. To construct model potential barrier profiles for each examined geometry, we rely on first-principles density-functional theory (DFT) calculations for the barrier heights and the shapes of the interface regions as well as on experimental data for the barrier widths. We show that even tiny variations in the atomic arrangement at the interface cause significant changes in the tunnel barrier parameters and, consequently, in electron transport properties. Especially, we find that variations in the crucial barrier heights and widths can be as large as 2 eV and 5 Å, respectively. Finally, to gain information about the average properties of the measured junction, we fit the conductance calculated within the Wentzel-Kramers-Brillouin approximation to the experimental data and interpret the fit parameters with the help of the DFT results.

  18. Relativity and Al^+ Optical Clocks

    NASA Astrophysics Data System (ADS)

    Chou, Chin-Wen; Hume, David B.; Wineland, David J.; Rosenband, Till

    2010-03-01

    We have constructed an optical clock based on quantum logic spectroscopy of an Al+ ion that has a fractional frequency inaccuracy of 8.6x10-18. The frequency of the ^1S0<->^3P0 clock transition is compared to that of a previously constructed Al^+ optical clock with a statistical measurement uncertainty of 7.0x10-18. The two clocks exhibit a relative stability of 2.8x10-15&-1/2circ;, and a fractional frequency difference of -1.8x10-17, consistent with the accuracy limit of the older clock. By comparing the frequencies of the clocks, we have observed relativistic effects, such as time dilation due to velocities less than 10 m/s and the gravitational red shift from a 0.33 m height change of one of the clocks.

  19. Mehr Objektivitaet im muendlichen Abitur (More Objectivity in the Oral Graduation Examination)

    ERIC Educational Resources Information Center

    Miklitz, Guenther

    1977-01-01

    Proposes, for the oral portion of the final (graduation) examination, the text as basic object, from which a section should be read aloud. A 15-point grading scale is described. Regarding content, performance in "informing,""interpreting and extrapolating," and "evaluating and discussion" are to be graded. (Text is in…

  20. Emerging mechanisms of molecular pathology in ALS

    PubMed Central

    Peters, Owen M.; Ghasemi, Mehdi; Brown, Robert H.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable. PMID:25932674

  1. [Coagulation behavior of Al13 species].

    PubMed

    Hu, Cheng-zhi; Liu, Hui-juan; Qu, Jiu-hui

    2006-12-01

    Coagulation behavior of Al13 species was examined in synthetic water with high alkalinity and high humic acid concentration from viewpoint of the transformation of Al hydrolysis products during the coagulation process. The results indicated that coagulation efficiency of Al coagulants positively correlated with the content of Al13 in the coagulation process. Aluminum chloride (AlCl3) was more effective than polyaluminum chloride (PACI) in removing turbidity and dissolved organic matter in the synthetic water because AlCl3 could not only generate Al13 species but also function as pH control agent in the coagulation process. During coagulation process pH control can improve coagulation process through regulating Al speciation, and AlCl3 benefited most from pH control.

  2. Synthesis of AlN/Al Polycrystals along with Al Nanoparticles Using Thermal Plasma Route

    SciTech Connect

    Kanhe, Nilesh S.; Nawale, A. B.; Kulkarni, N. V.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2011-07-15

    This paper for the first time reports the (200) oriented growth of hexagonal Aluminum nitride crystals during synthesis of aluminum nanoparticles in dc transferred arc thermal plasma reactor by gas phase condensation in nitrogen plasma. The structural and morphological study of as synthesized AlN crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.

  3. Investigations of Al-Dalang and Al-Hawashat meteorites

    NASA Astrophysics Data System (ADS)

    Gismelseed, A. M.; Abdallah, S. B.; Al-Rawas, A. D.; Al-Mabsali, F. N.; Widatallah, H. M.; Elzain, M. E.; Yousif, A. A.; Ericsson, T.; Annersten, H.

    2016-12-01

    Mössbauer spectroscopy, X-ray diffraction (XRD) measurements, and electron microprobe analysis (EMPA) have been performed on two meteorites named Al-Dalang and Al-Hawashat after identifying their falling sites in the Western region of Sudan. These two meteorites are ordinary chondrites with similar mineralogy. XRD and EMPA show that the two specimens consist of primary olivine, ortho-pyroxene and later crystallising clino-pyroxene as reaction rims against plagioclase. Fe-metal phases are dominated by kamacite (≈6 wt.% Ni) and minor amounts of tetrataenite (≈52 wt.% Ni). Troilite (FeS) and alabandite (MnS) are optically observed as sulphide phases. The Mössbauer measurements at 295 and 78 K are in agreement with the above characterizations, showing at least two paramagnetic doublets which are assigned to olivine and pyroxene and magnetic sextets assigned to kamacite (hyperfine field ≈33.5 T) and troilite FeS (hyperfine field ≈31 T).

  4. Al-Al2O3-Pd junction hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Okuyama, K.; Takinami, N.; Chiba, Y.; Ohshima, S.; Kambe, S.

    1994-07-01

    Al-Al2O3-Pd MIM (metal insulator metal) junctions fabricated on a glass substrate were tested as hydrogen sensors. The I-V (current versus voltage) characteristics of the junctions were measured at room temperature in a vacuum of 10-5 Torr and in H2 gas of 10-2-100 Torr. A significant increase in the current was observed upon introduction of H2 gas. This phenomenon is believed to occur due to the work function lowering of the hydrogen-absorbed Pd top electrode. The rise time was on the order of minutes, while the recovery time when hydrogen was purged was more than 20 h. However, when the junction was placed in an oxidizing ambient such as air, the recovery time was drastically reduced to the order of minutes, indicating that the device is operative as a hydrogen sensor in the atmospheric ambient. Hydrogen adsorption and desorption behavior of the Pd film was also investigated using a Pd coated quartz microbalance, and the results explained the current response of the Pd MIM junction to hydrogen in the presence of oxygen.

  5. Electronic spectroscopy of the Al +-Ar complex

    NASA Astrophysics Data System (ADS)

    Lei, Jie; Dagdigian, Paul J.

    1999-05-01

    The laser fluorescence excitation spectrum of the Al +-Ar complex near the Al + ion 3s3p 1P ← 3s 2 1S resonance transition is reported. An excited-state ( v', 0) progression and the (0, 1) hot band were observed. Rotational analysis revealed that these bands involve an electronic transition from the Al +-Ar X 1Σ+ ground state to the 1Σ+ state correlating with the Al +( 1P)+Ar asymptote. Rotational constants and upper-state vibrational constants and the dissociation energy were determined. The spectroscopic constants of the two observed Al +-Ar electronic states are compared with those for neutral AlAr states.

  6. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    DOE PAGES

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-13

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamicallymore » driven process.« less

  7. NiAl-base composite containing high volume fraction of AlN for advanced engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan (Inventor); Whittenbeger, John D. (Inventor); Lowell, Carl F. (Inventor)

    1994-01-01

    A particulate reinforced NiAl-AlN composite alloy has a NiAl matrix and greater than about 13 volume percent fine particles of AlN within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced NiAl-AlN composite alloy may be prepared by cryomilling prealloyed NiAl in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced NiAl-AlN composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCrAlY, FeCrAlY, and FeAl.

  8. Microstructure and Oxidation Behavior of Al and Al/NiCrAlY Coatings on Pure Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Gong, Xue; Zhang, Nannan; Zhang, Zhongli; Chen, Ruirun; Lin, Danyang

    2017-06-01

    To improve the oxidation resistance of Ti alloys, a NiCrAlY coating was deposited as diffusion barrier between aluminum overlay coating and pure Ti substrate by air plasma spraying method. The microstructure and oxidation behavior of Al coatings with and without NiCrAlY diffusion barrier were investigated in isothermal oxidation tests at 800 °C for 100 h. The results indicate that the weight gain of the Al/NiCrAlY coating was 4.16 × 10-5 mg2 cm-4 s-1, whereas that of the single Al coating was 9.52 × 10-5 mg2 cm-4 s-1 after 100 h oxidation. As compared with single Al coating, the Al/NiCrAlY coating revealed lower oxidation rate and excellent oxidation resistance by forming thin Al2O3 + NiO scales at overlaying coating/diffusion barrier and diffusion barrier/substrate interfaces. Meanwhile, the inward diffusion of Al and the outward diffusion of Ti were inhibited effectively by the NiCrAlY diffusion barrier.

  9. Consoer et al PFOS dataset

    EPA Pesticide Factsheets

    This ScienceHub entry was developed for the published paper: Consoer et al., 2016, Toxicokinetics of perfluorooctane sulfonate in rainow trout (Oncorhynchus mykiss), Environ. Toxicol. Chem. 35:717-727. Individual rainbow trout were exposed to PFOS by bolus injection (elimination studies) or by adding PFOS to incoming water (branchial uptake studies). The trout were fitted with indwelling catheters and urinary cannulae to permit periodic collection of blood and urine. Additional sampling was conducted to evaluate PFOS uptake from and elimination to respired water. Data obtained from each fish was evaluated using a clearance-volume pharmacokinetic model. Modeled kinetic parameters were then averaged to develop summary statistics which were used as a basis for interpreting modeled results and making comparisons to a previous study of rainbow trout exposed to perfluorooctanoate (PFOA; Consoer et al., 2014, Aquat. Toxicol. 156:65-73). The results of this study, combined with that of the previous PFOA study, suggest that PFOA is a substrate for renal transporters in fish while glomerular filtration alone may be sufficient to explain the observed renal elimination of PFOS. These findings demonstrate that models developed to predict the bioaccumulation of perfluoroalkyl acids by fish must account for differences in renal clearance of individual compounds.This dataset is associated with the following publication:Consoer, D., A. Hoffman , P. Fitzsimmons , P. Kosia

  10. Phosphorus Enhances Al Resistance in Al-resistant Lespedeza bicolor but not in Al-sensitive L. cuneata Under Relatively High Al Stress

    PubMed Central

    Sun, Qing Bin; Shen, Ren Fang; Zhao, Xue Qiang; Chen, Rong Fu; Dong, Xiao Ying

    2008-01-01

    Background and Aims Aluminium (Al) toxicity and phosphorus (P) deficiency often co-exist in acidic soils and limit crop production worldwide. Lespedeza bicolor is a leguminous forage species that grows very well in infertile, acidic soils. The objective of this study was to investigate the effects of Al and P interactions on growth of Lespedeza and the distributions of Al and P in two different Al-resistant species, and to explore whether P can ameliorate the toxic effect of Al in the two species. Methods Two species, Lespedeza bicolor and L. cuneata, were grown for 30 d with alternate Al and P treatments in a hydroponics system. Harvested roots were examined using a root-system scanner, and the contents of Al, P and other nutrient elements in the plants were determined using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Haematoxylin staining was used to observe the distribution of Al in the roots of seedlings. After pre-culture with or without P application, organic acids in the exudates of roots exposed to Al were held in an anion-exchange resin, eluted with 2 m HCl and then analysed using high-performance liquid chromatography (HPLC). Key Results Lespedeza bicolor exhibited a stronger Al resistance than did L. cuneata; Al exclusion mechanisms may mainly be responsible for resistance. P application alleviated the toxic effect of Al on root growth in L. bicolor, while no obvious effects were observed in L. cuneata. Much less Al was accumulated in roots of L. bicolor than in L. cuneata after P application, and the P contents in both roots and shoots increased much more for L. bicolor than for L. cuneata. Lespedeza bicolor showed a higher P/Al ratio in roots and shoots than did L. cuneata. P application decreased the Al accumulation in root tips of L. bicolor but not in L. cuneata. The amount of Al-induced organic acid (citrate and malate) exudation from roots pre-cultured with P was much less than from roots without P application; no malate and

  11. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jaing, Y; He, Y H; Xu, N P; Zou, J; Huang, B; Lui, C T

    2008-01-01

    Porous TieAl alloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porous TieAl alloys can have three crystalline phases (i.e., a2-Ti3Al, g-TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  12. Cenomanian-Turonian biostratigraphy of the Jardas Al Abid area, Al Jabal Al Akhdar, northeast Libya

    NASA Astrophysics Data System (ADS)

    El Qot, Gamal M.; Abdulsamad, Esam O.

    2016-09-01

    The Upper Cenomanian-Turonian succession exposed at Jardas al'Abid area consists mainly of carbonates with siliciclastic intercalations. This succession is subdivided lithostratigraphically into: Qasr al'Abid (Late Cenomanian) and Al Baniyah (Late Cenomanian-Coniacian) formations. This sequence is relatively rich in macrofossil assemblages especially bivalves, gastropods, and echinoids with rare ammonites. Based on the first occurrence (FO) and last occurrence (LO) of some index species of these macrofossil groups, an integrated biostratigraphic framework has been constructed. The studied Cenomanian-Turonian sequence is subdivided biostratigraphically into three ammonite biozones; Pseudaspidoceras pseudonodosoides Total Range Zone, Choffaticeras segne Total Range Zone, and Coilopoceras requienianum Total Range Zone. Based on the rest of macrofossil assemblages other than the ammonites, eight biozones were recognized; Mecaster batnensis Total Range Zone, Ceratostreon flabellatum-Neithea dutrugei Acme Zone, Costagyra olisiponensis Acme Zone, Pycnodonte (Phygraea) vesicularis vesiculosa Acme Zone, Mytiloides labiatus Total Range Zone = Mecaster turonensis Acme Zone, Rachiosoma rectilineatum-Curvostrea rouvillei-Tylostoma (T.) globosum Assemblage Zone, Radiolites sp.-Apricardia? matheroni Total Range Zone, and Nerinea requieniana Total Range Zone. Most of the proposed biozones are recorded for the first time from Libya. The integration among these biozones as well as local and inter-regional correlation of the biozones have been discussed. The stage boundaries of the studied stratigraphic intervals are discussed, where the Cenomanian/Turonian boundary is delineated at the last occurrence (LO) of Pseudaspidoceras pseudonodosoides (Choffat), while the Turonian/Coniacian boundary is delineated arbitrary being agree with the LO of the Turonian fauna.

  13. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH2(Al)

    NASA Astrophysics Data System (ADS)

    An, Yang; Li, Huiliang; Liu, Yuanyuan; Huang, Baibiao; Sun, Qilong; Dai, Ying; Qin, Xiaoyan; Zhang, Xiaoyang

    2016-01-01

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH2 (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO6-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.

  14. Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions

    SciTech Connect

    Ruiz-Salvador, A. Rabdel; Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W.

    2013-02-15

    We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

  15. Framework Al zoning in zeolite ECR-1.

    PubMed

    Shin, Jiho; Ahn, Nak Ho; Cho, Sung June; Ren, Limin; Xiao, Feng-Shou; Hong, Suk Bong

    2014-02-25

    Rietveld analyses of the synchrotron X-ray diffraction data for various cation forms of zeolite ECR-1 have demonstrated framework Al zoning, which parallels the alternation of Al-rich maz and Al-poor mor layers. This can be further supported by notable differences in the average bond valence of its 10 crystallographically distinct tetrahedral sites.

  16. Study of the Al/graphite interface

    NASA Astrophysics Data System (ADS)

    Lu, Hua; Shen, Dian-hong; Deng, Xin-fa; Xue, Qi-kun; Froumin, N.; Polak, M.

    2001-09-01

    Thin Al films with a thickness of 20-30nm were prepared by ultra-high vacuum deposition of Al onto a graphite surface parallel to a (0001) basal plane. The samples were annealed up to 1070K. X-ray photoelectron spectroscopy analysis has shown that for temperatures just higher than 770K, a little carbide occurs in the Al film and only an Al-C phase is present at the Al/graphite interface. After annealing at 970K, the Al4C3 phase can be observed and the binding energy of the Al2p electrons increases continuously from 72.7 to 74.2eV with increasing temperature up to 1070K. Auger electron spectroscopy depth profiles are measured to investigate the phases existing in the Al film as well as at the Al/graphite interface. It is found that the Al4C3 phase at the interface is the final product of a series of Al carbides from the interfacial reaction between Al and graphite.

  17. Nonstoichiometry of Al-Zr intermetallic phases

    SciTech Connect

    Radmilovic, V.; Thomas, G.

    1994-06-01

    Nonstoichiometry of metastable cubic {beta}{prime} and equilibrium tetragonal {beta} Al-Zr intermetallic phases of the nominal composition Al{sub 3}Zr in Al-rich alloys has been extensively studied. It is proposed that the ``dark contrast`` of {beta}{prime} core in {beta}{prime}/{sigma}{prime} complex precipitates, in Al-Li-Zr based alloys, is caused by incorporation of Al and Li atoms into the {beta}{prime} phase on Zr sublattice sites, forming nonstoichiometric Al-Zr intermetallic phases, rather than by Li partitioning only. {beta}{prime} particles contain very small amounts of Zr, approximately 5 at.%, much less than the stoichiometric 25 at.% in the Al{sub 3}Zr metastable phase. These particles are, according to simulation of high resolution images, of the Al{sub 3}(Al{sub 0.4}Li{sub 0.4}Zr{sub 0.2}) type. Nonstoichiometric particles of average composition Al{sub 4}Zr and Al{sub 6}Zr are observed also in the binary Al-Zr alloy, even after annealing for several hours at 600{degree}C.

  18. Opportunity's 'Rub al Khali' Panorama

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR)

    This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.'

    The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth.

    The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers.

    Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars.

    Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can

  19. Cyclic oxidation resistance of a reaction milled NiAl-AlN composite

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.; Whittenberger, J. D.

    1990-01-01

    Based upon recent mechanical property tests a NiAl-AlN composite produced by cryomilling has very attractive high temperature strength. This paper focuses on the oxidation resistance of the NiAl-AlN composite at 1473 and 1573 K as compared to that of Ni-47Al-0.15Zr, one of the most oxidation resistant intermetallics. The results of cyclic oxidation tests show that the NiAl-AlN composite has excellent properties although not quite as good as those of Ni-47Al-0.15Zr. The onset of failure of the NiAl-AlN was unique in that it was not accompanied by a change in scale composition from alumina to less protective oxides. Failure in the composite appears to be related to the entrapment of AlN particles within the alumina scale.

  20. Wear behavior of Al-Al{sub 3}Ti composite manufactured by a centrifugal method

    SciTech Connect

    Watanabe, Yoshimi; Yamanaka, Noboru; Fukui, Yasuyoshi

    1999-12-01

    The purpose of the present study was to develop a wear-resistant, light Al-Al{sub 3}Ti composite material. An Al-Al{sub 3}Ti composite specimen was machined from a thick-walled tube of Al-Al{sub 3}Ti functionally graded material (FGM) manufactured by the centrifugal method from a commercial ingot of Al-5 mass% Ti master alloy. The alloy was heated to a temperature where solid Al{sub 3}Ti particles resided in a liquid Al matrix, and then the centrifugal method was carried out. Al{sub 3}Ti particles in a commercial alloy ingot exist as platelets, and this shape was maintained through the casting. Three kinds of wear specimens were prepared, taking into account the morphology of the Al{sub 3}Ti particles in the thick-walled FGM tube; the Al{sub 3}Ti particles were arranged with their platelet planes nearly normal to the radial direction as a result of the applied centrifugal force. The wear resistance of the Al-Al{sub 3}Ti composite was significantly higher than that of pure Al. Wear-resistance anisotropy and dissolution of the Al{sub 3}Ti into the Al matrix at the near-surface region, around 100 {micro}m in depth, were also observed. The mechanism of the supersaturated-layer formation and the origin of the anisotropic wear resistance are discussed.

  1. Systems Engineering Techniques for ALS Decision Making

    NASA Technical Reports Server (NTRS)

    Rodriquez, Luis F.; Drysdale, Alan E.; Jones, Harry; Levri, Julie A.

    2004-01-01

    The Advanced Life Support (ALS) Metric is the predominant tool for predicting the cost of ALS systems. Metric goals for the ALS Program are daunting, requiring a threefold increase in the ALS Metric by 2010. Confounding the problem, the rate new ALS technologies reach the maturity required for consideration in the ALS Metric and the rate at which new configurations are developed is slow, limiting the search space and potentially giving the perspective of a ALS technology, the ALS Metric may remain elusive. This paper is a sequel to a paper published in the proceedings of the 2003 ICES conference entitled, "Managing to the metric: an approach to optimizing life support costs." The conclusions of that paper state that the largest contributors to the ALS Metric should be targeted by ALS researchers and management for maximum metric reductions. Certainly, these areas potentially offer large potential benefits to future ALS missions; however, the ALS Metric is not the only decision-making tool available to the community. To facilitate decision-making within the ALS community a combination of metrics should be utilized, such as the Equivalent System Mass (ESM)-based ALS metric, but also those available through techniques such as life cycle costing and faithful consideration of the sensitivity of the assumed models and data. Often a lack of data is cited as the reason why these techniques are not considered for utilization. An existing database development effort within the ALS community, known as OPIS, may provide the opportunity to collect the necessary information to enable the proposed systems analyses. A review of these additional analysis techniques is provided, focusing on the data necessary to enable these. The discussion is concluded by proposing how the data may be utilized by analysts in the future.

  2. Pathogene Mikroorganismen

    NASA Astrophysics Data System (ADS)

    Wagner, Martin

    Infektionen, die vom Tier auf den Menschen übertragen werden, werden als Zoonosen bezeichnet. Pathogene Mikroorganismen können entweder durch Mensch-Mensch, Mensch-Tier-Kontakt oder durch Kontakt mit kontaminierten Vektoren übertragen werden [39]. Vektoren können einerseits belebt (z. B. blutsaugende Insekten), andererseits unbelebt sein. Kontaminierte Lebensmittel und Wasser gehören zu den wichtigsten unbelebten Vektoren. Neben Lebensmitteln können aber auch kontaminierte Gegenstände oder der Kontakt mit Kontaminationsquellen in der Umwelt Auslöser von Krankheitsfällen sein. Weltweit sind mehr als 1400 krankheitsverursachende biologische Agentien bekannt, von denen über 60 % ein zoonotisches Potenzial aufweisen. Als Ergebnis von Expertengesprächen wurde kürzlich berichtet, dass etwa 3 bis 4, meist virale, neu auftretende Infektionskrankheiten ("emerging diseases“) pro Jahr erwartet werden können [15]. Es handelt sich bei diesen Vorgängen aber nicht nur um das Auftauchen vollkommen neuer oder unbeschriebener Spezies, sondern auch um evolutionsbedingte Anpassungen von mikrobiellen Populationen an neue Bedingungen in ihrem Ökosystem [7]. Molekulare Analysen an Umweltchlamydien erbrachten Hinweise, dass die Evolution erste genetische Pathogenitätsmerkmale in dieser Spezies schon vor 700 Mio. Jahren entstehen ließ [14]. Viele Faktoren befeuern den Prozess der Anpassung, unter anderem auch alle Strategien, mit denen der Mensch seit Jahrtausenden versucht, Lebensmittel sicher und haltbar zu machen. Als die treibenden Kräfte des Auftretens neuer Krankheitserreger werden in der Gegenwart vor allem das sich ändernde Weltklima, die globalen Warenströme und die sich verändernden Konsumgewohnheiten genannt. Es steht auch außer Zweifel, dass viele dieser Erreger Tiere als ihr natürliches Reservoir haben werden, d. h. Zoonosen im klassischen Sinne sind [15].

  3. Magnetism of Al-substituted magnetite reduced from Al-hematite

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoxia; Liu, Qingsong; Zhao, Xiang; Roberts, Andrew P.; Heslop, David; Barrón, Vidal; Torrent, José

    2016-06-01

    Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO2 and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.

  4. How to reduce the Al-texture in AlN films during film preparation

    NASA Astrophysics Data System (ADS)

    Yin, Ju-qian; Chen, Xi-ming; Yang, Bao-he; Zhang, Qian; Wu, Xiao-guo

    2012-09-01

    The preparation of aluminum nitrogen (AlN) film without Al texture is of great significance for the manufacture of high-performance surface acoustic wave (SAW) device. We research the process factors which bring Al into AlN film due to radio frequency (RF) magnetron sputtering system, and discuss how the process parameters influence the AlN thin film containing Al. In the research, it is found that the high sputtering power, the low deposition pressures and low partial pressure of Ar can lead to growing Al-texture during AlN thin film preparation, and the experiment also shows that filling the chamber with nitrogen gas can recrystallize a small amount of Al composition into AlN film during the annealing process in the high temperature environment.

  5. Atom probe analysis of AlN interlayers in AlGaN/AlN/GaN heterostructures

    SciTech Connect

    Mazumder, Baishakhi; Kaun, Stephen W.; Speck, James S.; Lu, Jing; Keller, Stacia; Mishra, Umesh K.

    2013-03-18

    Atom probe tomography was used to characterize AlN interlayers in AlGaN/AlN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy (PAMBE), NH{sub 3}-based molecular beam epitaxy (NH{sub 3}-MBE), and metal-organic chemical vapor deposition (MOCVD). The PAMBE-grown AlN interlayer had the highest purity, with nearly 100% of group-III sites occupied by Al. The group-III site concentrations of Al for interlayers grown by NH{sub 3}-MBE and MOCVD were {approx}85% and {approx}47%, respectively. Hall measurements were performed to determine the two-dimensional electron gas mobility and sheet concentration. Sheet concentrations were {approx}25%-45% higher with molecular beam epitaxy than with MOCVD, and these results matched well with atom probe data.

  6. A comparison of mechanical properties between Al and Al3Mg

    NASA Astrophysics Data System (ADS)

    Yang, Rong; Tang, Bin; Gao, Tao

    2016-11-01

    On the basis of first principles calculations, we have calculated the elastic properties, stress-strain relations, ideal tensile strengths, ideal shear strengths, and the ideal compressed strengths of Al and Al3Mg. The stress-strain relations of Al3Mg are strikingly similar to those of Al, indicating that the crystal structure appears to be more important than the identity of the individual atoms during uniaxial deformation. Al3Mg is found to have larger moduli and higher strengths than Al but less ductile than Al. So Al3Mg is expected to be a harder material, consistent with its exploitation in Al precipitate-hardening mechanisms. The calculated elastic properties, tensile strengths and shear strengths of Al are consistent with experimental values or previous theoretical results. We also use another method (molecular dynamics (MD) simulations) to recalculate elastic constants, ideal tensile and compressed strength of Al3Mg for checking and comparing. We find that the results obtained by the two methods agree well with each other. The failure modes under uniaxial <100> tension are also explored for Al and Al3Mg. Our calculations confirm that Al fail by shear and predict that Al3Mg also fail by shear.

  7. Ti{sub 2}AlN thin films synthesized by annealing of (Ti+Al)/AlN multilayers

    SciTech Connect

    Cabioch, Thierry; Alkazaz, Malaz; Beaufort, Marie-France; Nicolai, Julien; Eyidi, Dominique; Eklund, Per

    2016-08-15

    Highlights: • Epitaxial thin films of the MAX phase Ti{sub 2}AlN are obtained by thermal annealing. • A new metastable (Ti,Al,N) solid solution with the structure of α-T is evidenced. • The formation of the MAX phase occurs at low temperature (600 °C). - Abstract: Single-phase Ti{sub 2}AlN thin films were obtained by annealing in vacuum of (Ti + Al)/AlN multilayers deposited at room temperature by magnetron sputtering onto single-crystalline (0001) 4H-SiC and (0001) Al{sub 2}O{sub 3} substrates. In-situ X-ray diffraction experiments combined with ex-situ cross-sectional transmission electron microscopy observations reveal that interdiffusion processes occur in the multilayer at a temperature of ∼400 °C leading to the formation of a (Ti, Al, N) solid solution, having the hexagonal structure of α-Ti, whereas the formation of Ti{sub 2}AlN occurs at 550–600 °C. Highly oriented (0002) Ti{sub 2}AlN thin films can be obtained after an annealing at 750 °C.

  8. Reply to Vance et al.

    SciTech Connect

    Woon-Chee Yee; Elliott, J.L; Kwon, J.M.; Goodfellow, P.

    1996-07-01

    In our report of a family with a motor and sensory polyneuropathy that was linked to chromosome 3q, we classified this neuropathy as a form of hereditary motor and sensory neuropathy II (HMSN II, also known as {open_quotes}CMT2{close_quotes}). Doubts have been raised by Vance et al. as to whether this neuropathy should be classified as hereditary sensory autonomic neuropathy I (HSAN I) instead of HMSN II. While it is reasonable to raise such doubts, we believe that the neuropathy is best designated as HMSN II for the reasons described below. The group of disorders described as HSAN are characterized by primary or predominant involvement of sensory and autonomic neurons that fail to develop or that undergo atrophy and degeneration. These disorders were extensively reviewed by Dyck and Ohta, who initially described them as the hereditary sensory neuropathies (HSN). It was Dyck who subsequently suggested that these disorders be designated HSAN rather than HSN, because of the presence of autonomic involvement. 8 refs.

  9. Response to Durif et al.

    PubMed

    Putman, Nathan F; Naisbett-Jones, Lewis C; Stephenson, Jessica F; Ladak, Sam; Young, Kyle A

    2017-09-25

    Our recent study [1] in Current Biology used a magnetic displacement experiment and simulations in an ocean circulation model to provide evidence that young European eels possess a 'magnetic map' that can aid their marine migration. Our results support two major conclusions: first, young eels distinguish among magnetic fields corresponding to locations across their marine range; second, for the fields that elicited significantly non-random orientation, swimming in the experimentally observed direction from the corresponding locations would increase entrainment in the Gulf Stream system. In their critique, Durif et al.[2] seem to conflate the separate and potentially independent 'map step' and 'compass step' of animal navigation. In the map step, an animal derives positional information to select a direction, whereas in the compass step the animal maintains that heading [3,4]. Our experiment was designed such that differences in eel orientation among treatments would indicate an ability to use the magnetic field as a map; the compass cue(s) used by eels was not investigated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Seltzer_et_al_2016

    EPA Pesticide Factsheets

    This dataset supports the modeling study of Seltzer et al. (2016) published in Atmospheric Environment. In this study, techniques typically used for future air quality projections are applied to a historical 11-year period to assess the performance of the modeling system when the driving meteorological conditions are obtained using dynamical downscaling of coarse-scale fields without correcting toward higher resolution observations. The Weather Research and Forecasting model and the Community Multiscale Air Quality model are used to simulate regional climate and air quality over the contiguous United States for 2000-2010. The air quality simulations for that historical period are then compared to observations from four national networks. Comparisons are drawn between defined performance metrics and other published modeling results for predicted ozone, fine particulate matter, and speciated fine particulate matter. The results indicate that the historical air quality simulations driven by dynamically downscaled meteorology are typically within defined modeling performance benchmarks and are consistent with results from other published modeling studies using finer-resolution meteorology. This indicates that the regional climate and air quality modeling framework utilized here does not introduce substantial bias, which provides confidence in the method??s use for future air quality projections.This dataset is associated with the following publication:Seltzer, K., C

  11. Dentalwerkstoffe und Dentalimplantate - Teil 2

    NASA Astrophysics Data System (ADS)

    Faltermeier, Andreas

    Wie in allen Bereichen der Medizin findet auch in der Zahnmedizin eine kontinuierliche Weiterentwicklung der verwendeten Werkstoffe statt. Gerade für Zahnersatz werden Werkstoffe gesucht, die zum einen ästhetisch, zum anderen haltbar und darüber hinaus auch körperverträglich sind. Auch steigt immer mehr der Wunsch der Patienten nach ästhetischen und zugleich biokompatiblen Materialien. Wurde früher fast ausschließlich als Füllungsmaterial im Seitenzahngebiet quecksilberhaltiges Amalgam verwendet, hat der Zahnarzt heutzutage eine große Auswahl an verschiedenen zahnfarbenen Materialien: zum einen werden sog. Komposite verwendet, das aus einer Polymermatrix mit eingebetteten Füllstoffen besteht, zum anderen können diverse Dentalkeramiken verwendet werden. Besonders die Verwendung von Hochleistungskeramiken, wie beispielsweise Zirkonoxid, das sich bereits als Bremsscheiben für Sportwägen, Hitzeschilde im Space Shuttle und als Kugelköpfe künstlicher Hüftgelenke bewährt hat, spielt heutzutage eine große Rolle bei der Verdrängung des Metalls aus der Mundhöhle. War es früher nur möglich, einen verloren gegangen Zahn mittels einer Brücke, die ein Beschleifen der Nachbarzähne zur Folge hat, oder durch herausnehmbaren Zahnersatz zu ersetzen, ist es heutzutage mit der modernen Implantologie möglich, Zahnersatz zahnschonend einzugliedern. Auch kann mittels Dentalimplantaten dem Wunsch vieler Patienten nach festem Zahnersatz anstelle eines herausnehmbaren Zahnersatzes entsprochen werden. So kann mit Hilfe neuer biokompatiblen Werkstoffe sowohl der ästhetische Anspruch befriedigt als auch das Selbstwertgefühl vieler Patienten angehoben werden.

  12. Growth and stress-induced transformation of zinc blende AlN layers in Al-AlN-TiN multilayers

    SciTech Connect

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang -Yang; Misra, Amit

    2015-12-18

    We report that AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN.

  13. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers

    PubMed Central

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN. PMID:26681109

  14. Growth and stress-induced transformation of zinc blende AlN layers in Al-AlN-TiN multilayers

    DOE PAGES

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; ...

    2015-12-18

    We report that AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN.

  15. Protein Aggregation Inhibitors for ALS Therapy

    DTIC Science & Technology

    2013-07-01

    C. P. Multiple antioxidants in the prevention and treatment of Alzheimer disease: analysis of biologic rationale. Clin. Neuropharmacol. 2000, 23, 2...E.; Pfeiffer, E.; Jin, S.; Gamst, A.; Grundman, M.; Thomas, R.; Thal, L. J. Estrogen replacement therapy for treatment of mild to moderate Alzheimer ...general, exhibit a significant increased risk of developing ALS. There is no effective treatment for ALS; riluzole, the only FDA-approved drug for ALS

  16. Orientation relationship of eutectoid FeAl and FeAl2

    PubMed Central

    Scherf, A.; Kauffmann, A.; Kauffmann-Weiss, S.; Scherer, T.; Li, X.; Stein, F.; Heilmaier, M.

    2016-01-01

    Fe–Al alloys in the aluminium range of 55–65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ∊ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [J. Cryst. Growth (1978 ▸), 43, 745] and Hirata et al. [Philos. Mag. Lett. (2008 ▸), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [Acta Cryst. (2010 ▸), C66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a 〈112〉 crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼〈110〉FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. PMID:27047304

  17. Tensile Behavior of Al2o3/feal + B and Al2o3/fecraly Composites

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

    1995-01-01

    The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

  18. Internal Detoxification Mechanism of Al in Hydrangea (Identification of Al Form in the Leaves).

    PubMed Central

    Ma, J. F.; Hiradate, S.; Nomoto, K.; Iwashita, T.; Matsumoto, H.

    1997-01-01

    An internal detoxification mechanism for Al was investigated in an Al-accumulating plant, hydrangea (Hydrangea macrophylla), focusing on Al forms present in the cells. The leaves of hydrangea contained as much as 15.7 mmol Al kg-1 fresh weight, and more than two-thirds of the Al was found in the cell sap. Using 27Al- nuclear magnetic resonance, the dominant peak of Al was observed at a chemical shift of 11 to 12 parts per million in both intact leaves and the extracted cell sap, which is in good accordance with the chemical shift for the 1:1 Al-citrate complex. Purification of cell sap by molecular sieve chromatography (Sephadex G-10) combined with ion-exclusion chromatography indicated that Al in fractions with the same retention time as citric acid contributed to the observed 27Al peak in the intact leaves. The molar ratio of Al to citric acid in the crude and purified cell sap approximated 1. The structure of the ligand chelated with Al was identified to be citric acid. Bioassay experiments showed that the purified Al complex from the cell sap did not inhibit root elongation of corn (Zea mays L.) and the viability of cells on the root tip surface was also not affected. These observations indicate that Al is bound to citric acid in the cells of hydrangea leaves. PMID:12223659

  19. First-principles study of the Al(001)-Al3Nb(001) interfacial properties

    NASA Astrophysics Data System (ADS)

    Ding, Yanhong; Xu, Rui

    2017-03-01

    The adhesion, interfacial energy and bonding on fcc-Al(001)/D022-Al3Nb(001) interface were investigated using density functional calculations. Considering different terminations of Al3Nb(001) (Al+Nb-terminated and Al-terminated) and stacking sites (top-, bridge- and center-sites), six Al(001)/Al3Nb(001) models were calculated. For the models with same stacking site, Al+Nb-terminated model has larger work of adhesion (Wad) than the Al-terminated one. For the models with same termination, the work of adhesion increases, and the interface energy decreases as the order of center-sited, bridge-sited and top-sited. Al+Nb-terminated-center-sited and Al-terminated-center-sited models are more stable among six models. The interfacial bonding was discussed with analysis of valence electron density distribution and partial density of states (PDOS). The bonding is mainly contributed from Al-Nb covalent bonds and Al-Al metallic interactions.

  20. Reactivity of aluminum cluster anions with ammonia: selective etching of Al11(-) and Al12(-).

    PubMed

    Grubisic, Andrej; Li, Xiang; Gantefoer, Gerd; Bowen, Kit H; Schnöckel, Hansgeorg; Tenorio, Francisco J; Martinez, Ana

    2009-11-14

    Reactivity of aluminum cluster anions toward ammonia was studied via mass spectrometry. Highly selective etching of Al(11)(-) and Al(12)(-) was observed at low concentrations of ammonia. However, at sufficiently high concentrations of ammonia, all other sizes of aluminum cluster anions, except for Al(13)(-), were also observed to deplete. The disappearance of Al(11)(-) and Al(12)(-) was accompanied by concurrent production of Al(11)NH(3)(-) and Al(12)NH(3)(-) species, respectively. Theoretical simulations of the photoelectron spectrum of Al(11)NH(3)(-) showed conclusively that its ammonia moiety is chemisorbed without dissociation, although in the case of Al(12)NH(3)(-), dissociation of the ammonia moiety could not be excluded. Moreover, since differences in calculated Al(n)(-) + NH(3) (n=9-12) reaction energies were not able to explain the observed selective etching of Al(11)(-) and Al(12)(-), we concluded that thermodynamics plays only a minor role in determining the observed reactivity pattern, and that kinetics is the more influential factor. In particular, the conversion from the physisorbed Al(n)(-)(NH(3)) to chemisorbed Al(n)NH(3)(-) species is proposed as the likely rate-limiting step.

  1. Response to Signorovitch et al.

    PubMed

    Flot, Jean-François; Debortoli, Nicolas; Hallet, Bernard; Van Doninck, Karine

    2016-08-22

    Signorovitch et al.[1] comment that an Oenothera-like meiosis [2] could produce a pattern similar to what we observed in our study of natural isolates of the bdelloid rotifer Adineta vaga, which we attributed to horizontal gene transfers (HGTs) [3]. Indeed, our HGT hypothesis appears at first sight difficult to conciliate with their observation of a congruent pattern of allele sharing at four large loci possibly located on different chromosomes [4]. However, one might imagine conditions under which massive horizontal gene transfer between bdelloid individuals could produce such a pattern, notably if the individuals involved had previously lost most of their heterozygosity because of their exposure to frequent desiccation (which produces DNA double-strand breaks [5]). In the published A. vaga genome the loss of heterozygosity due to large-scale gene conversion events or break-induced replication covers only about 10% of the genome [6], but this percentage may be much higher in environmental isolates that often experience dessication. Besides, if an Oenothera-like mode of meiosis occurs in bdelloids frequently enough to be detected in a single sampling of 29 individuals (as in [4]), one would expect males and meiosis to be observed at least occasionally, and instances of congruent allele sharing across loci should turn up frequently in genetic surveys. This was not the case in [3]: among the 82 A. vaga individuals sequenced for four nuclear markers, no trio of individuals presented congruent patterns of shared sequences at different loci. For these reasons, and in the absence of any direct evidence for an Oenothera-like meiosis in bdelloids, we still consider inter-bdelloid HGTs a more parsimonious explanation for our results. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Al Pie De La Letra

    PubMed Central

    Ovbiagele, Bruce

    2014-01-01

    Background and Purpose Ethnic minorities are at higher stroke risk than non-Hispanic whites yet are less likely to have optimal vascular risk factor control. There is a need to develop culturally sensitive strategies for enhancing vascular risk reduction in minority patients with stroke. This study aimed to develop a postdischarge report card to boost treatment adherence among elderly Spanish-speaking patients with stroke within an urban health system. Methods This study included a total of 13 Spanish-only speaking participants aged ≥60 years discharged from a local government hospital in Los Angeles within 18 months of an index ischemic stroke and 6 caregivers engaged in focus groups and interviews. Structured interviews were conducted with 11 care providers and 9 administrators at the hospital. Framework analysis examined the data and elicited themes to adapt a pre-existing patient report card tool. Results Spontaneously using the same phrase, “Al pie de la letra,” several participants expressed a need to follow medical instructions accurately to prevent recurrent stroke and identified barriers/facilitators for doing so. They made comments about the pre-existing report card, advising several changes, including the clarification of phrases, and written instructions to explain the need for the card and how to fill it out. The providers and administrators recommended avenues for successfully using the card at the hospital. A new report card was created that incorporated all major perspectives. Conclusions Crafting a culturally sensitive tool for promoting treatment adherence in elderly Spanish-only-speaking patients with stroke within an urban health system using a participatory methodology is feasible. The efficacy of this new report card should be tested in a randomized controlled trial. PMID:20167904

  3. Genetics of Familial and Sporadic ALS

    ClinicalTrials.gov

    2017-01-04

    Amyotrophic Lateral Sclerosis (ALS); Familial Amyotrophic Lateral Sclerosis; Amyotrophic Lateral Sclerosis With Frontotemporal Dementia; Lou Gehrig's Disease; Motor Neuron Disease; Primary Lateral Sclerosis

  4. Mitochondrial disfunction as a cause of ALS.

    PubMed

    Pizzuti, Antonio; Petrucci, Simona

    2011-03-01

    Recent studies on patient with sporadic ALS and on in vitro and in vivo models of mendelian diseases have been addressed toward the unravelling of the mitochondrial behaviour in ALS, whether as a primarily pathogenic factor, or as a fundamental contributor to the cell death. Morphological evidence suggests mitochondria pathology in ALS and many physiological mechanisms involving these organelles appear deranged in ALS, such as energy production, apoptotic triggering, calcium homeostasis and axonal transport of mitochondria. The article briefly addresses recent advances on this field.

  5. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

    NASA Astrophysics Data System (ADS)

    Pstruś, Janusz; Gancarz, Tomasz

    2014-05-01

    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  6. Superbend era begins swiftly at the ALS

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2001-11-29

    The successful installation and commissioning of high-field superconducting bend magnets (superbends) in three curved sectors of ALS storage ring was the first time the magnet lattice of an operating synchrotron light source has been retrofitted in this fundamental way. As a result, the ALS now offers an expanded spectral range well into the hard x-ray region without compromising either the number of undulators or their high brightness in the soft x-ray region for which the ALS design was originally optimized. In sum, when the superbend-enhanced ALS started up for user operations in October 2001, it marked the beginning of a new era in its history.

  7. Spin-dependent tunneling junctions with AlN and AlON barriers

    NASA Astrophysics Data System (ADS)

    Sharma, Manish; Nickel, Janice H.; Anthony, Thomas C.; Wang, Shan X.

    2000-10-01

    We report on ferromagnetic spin-dependent tunneling (SDT) junctions with NiFe/AlN/NiFe and NiFe/AlON/NiFe structures. Good barriers were formed by plasma nitridation and oxy-nitridation of Al films. Tunneling magnetoresistance ratios (TMR) up to 18% were observed at room temperature. The devices exhibit lower resistance-area products than those seen in reference junctions with Al2O3 barriers. The degradation in TMR at higher bias voltages is found to be less than that found in standard alumina junctions. AlN and AlON could thus be alternate materials for the tunnel barrier in SDT junctions.

  8. Processing and Mechanical Properties of Directionally Solidified NiAl/NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1994-01-01

    Promising creep strengths were found for a directionally solidified NiAl-NiAlTa alloy when compared to other NiAl based intermetallics. The directionally solidified alloy had an off-eutectic composition that resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of the two phase alloy was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Alloying additions that may improve the room temperature toughness by producing multiphase alloys are discussed.

  9. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    NASA Astrophysics Data System (ADS)

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-07-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits.

  10. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions.

    PubMed

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-07-12

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits.

  11. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    PubMed Central

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  12. Microstructural and Phase Composition Differences Across the Interfaces in Al/Ti/Al Explosively Welded Clads

    NASA Astrophysics Data System (ADS)

    Fronczek, Dagmara Malgorzata; Chulist, Robert; Litynska-Dobrzynska, Lidia; Lopez, Gabriel Alejandro; Wierzbicka-Miernik, Anna; Schell, Norbert; Szulc, Zygmunt; Wojewoda-Budka, Joanna

    2017-06-01

    The microstructure and phase composition of Al/Ti/Al interfaces with respect to their localization were investigated. An aluminum-flyer plate exhibited finer grains located close to the upper interface than those present within the aluminum-base plate. The same tendency, but with a higher number of twins, was observed for titanium. Good quality bonding with a wavy shape and four intermetallic phases, namely, TiAl3, TiAl, TiAl2, and Ti3Al, was only obtained at the interface closer to the explosive material. The other interface was planar with three intermetallic compounds, excluding the metastable TiAl2 phase. As a result of a 100-hour annealing at 903 K (630 °C), an Al/TiAl3/Ti/TiAl3/Al sandwich was manufactured, formed with single crystalline Al layers. A substantial difference between the intermetallic layer thicknesses was measured, with 235.3 and 167.4 µm obtained for the layers corresponding to the upper and lower interfaces, respectively. An examination by transmission electron microscopy of a thin foil taken from the interface area after a 1-hour annealing at 825 K (552 °C) showed a mixture of randomly located TiAl3 grains within the aluminum. Finally, the hardness results were correlated with the microstructural changes across the samples.

  13. Influence of AlN thickness on AlGaN epilayer grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Jayasakthi, M.; Juillaguet, S.; Peyre, H.; Konczewicz, L.; Baskar, K.; Contreras, S.

    2016-10-01

    AlGaN/AlN layers were grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The AlN buffer thickness was varied from 400 nm to 800 nm. The AlGaN layer thickness was 1000 nm. The crystalline quality, thickness and composition of AlGaN were determined using high resolution X-ray diffraction (HRXRD). The threading dislocation density (TDD) was found to decrease with increase of AlN layer thickness. Reciprocal space mapping (RSM) was used to estimate the strain and relaxation between AlGaN and AlN. The optical properties of AlGaN layers were investigated by temperature dependent photoluminescence (PL). PL intensities of AlGaN layers increases with increasing the AlN thickness. The surface morphology of AlGaN was studied by atomic force microscopy (AFM). Root mean square (RMS) roughness values were found to be decreased while increase of AlN thickness.

  14. Microstructural and Phase Composition Differences Across the Interfaces in Al/Ti/Al Explosively Welded Clads

    NASA Astrophysics Data System (ADS)

    Fronczek, Dagmara Malgorzata; Chulist, Robert; Litynska-Dobrzynska, Lidia; Lopez, Gabriel Alejandro; Wierzbicka-Miernik, Anna; Schell, Norbert; Szulc, Zygmunt; Wojewoda-Budka, Joanna

    2017-09-01

    The microstructure and phase composition of Al/Ti/Al interfaces with respect to their localization were investigated. An aluminum-flyer plate exhibited finer grains located close to the upper interface than those present within the aluminum-base plate. The same tendency, but with a higher number of twins, was observed for titanium. Good quality bonding with a wavy shape and four intermetallic phases, namely, TiAl3, TiAl, TiAl2, and Ti3Al, was only obtained at the interface closer to the explosive material. The other interface was planar with three intermetallic compounds, excluding the metastable TiAl2 phase. As a result of a 100-hour annealing at 903 K (630 °C), an Al/TiAl3/Ti/TiAl3/Al sandwich was manufactured, formed with single crystalline Al layers. A substantial difference between the intermetallic layer thicknesses was measured, with 235.3 and 167.4 µm obtained for the layers corresponding to the upper and lower interfaces, respectively. An examination by transmission electron microscopy of a thin foil taken from the interface area after a 1-hour annealing at 825 K (552 °C) showed a mixture of randomly located TiAl3 grains within the aluminum. Finally, the hardness results were correlated with the microstructural changes across the samples.

  15. Effects of renal impairment on aluminum (Al) kinetics and Al-induced toxicity

    SciTech Connect

    Yokel, R.A.; McNamara, P.J.

    1986-03-01

    Al-induced toxicity most commonly occurs in the renally impaired. To study the influence of renal impairment on Al kinetics and toxicity, renally impaired rabbits were prepared by the remnant kidney procedure. Six weeks after partial nephrectomy creatinine clearance was 21% of controls and serum creatinine, BUN, Ca, and PO/sub 4/ were 222, 248, 122, and 50% of presurgery levels respectively. Serum Al kinetics after i.v. Al were: Al clearance 27%, initial and steady state volumes of distribution 50 and 80%, half life 362% and mean residence time 300% of controls (renally intact rabbits). Beginning 9 weeks after partial nephrectomy, rabbits received 145 to 160 ..mu..mole Al/kg s.c. daily, 5 x weekly x 4 weeks. Acquisition of a classically conditioned reflex (nictitating membrane extension) was impaired comparable to that produced by 100-200 ..mu..mole Al in controls but retention and extinction deficits were greater than those seen after 400 ..mu..mole Al in controls. Tissue Al concentrations were less than those seen after 200 ..mu..mole Al in controls. Body weight was comparable to that produced by 400 ..mu..mole Al in controls. These results suggest that renal impairment alters Al serum distribution, impairs its clearance, and increases the Al-induced impairment of memory and body weight gain.

  16. Diana Al-Hadid: Identity and Heritage

    ERIC Educational Resources Information Center

    Jungerberg, Tom; Smith, Anna; Borsh, Colleen

    2012-01-01

    Diana Al-Hadid's sculptures reflect the many locations, cultures, histories, and mythologies that have shaped her as an artist. In large-scale works which have the appearance of architectural ruins, Al-Hadid employs imagery drawn from many diverse interests including science and technology, history, and literature. She also incorporates images and…

  17. Diana Al-Hadid: Identity and Heritage

    ERIC Educational Resources Information Center

    Jungerberg, Tom; Smith, Anna; Borsh, Colleen

    2012-01-01

    Diana Al-Hadid's sculptures reflect the many locations, cultures, histories, and mythologies that have shaped her as an artist. In large-scale works which have the appearance of architectural ruins, Al-Hadid employs imagery drawn from many diverse interests including science and technology, history, and literature. She also incorporates images and…

  18. Durability Assessment of TiAl Alloys

    NASA Technical Reports Server (NTRS)

    Draper, Susan L.; Lerch, Bradley A.

    2008-01-01

    The durability of TiAl is a prime concern for the implementation of TiAl into aerospace engines. Two durability issues, the effect of high temperature exposure on mechanical properties and impact resistance, have been investigated and the results are summarized in this paper. Exposure to elevated temperatures has been shown to be detrimental to the room temperature ductility of gamma alloys with the most likely mechanisms being the ingress of interstitials from the surface. Fluorine ion implantation has been shown to improve the oxidation resistance of gamma alloys, and ideally it could also improve the environmental embrittlement of high Nb content TiAl alloys. The effect of F ion implantation on the surface oxidation and embrittlement of a third generation, high Nb content TiAl alloy (Ti-45Al-5Nb-B-C) were investigated. Additionally, the ballistic impact resistance of a variety of gamma alloys, including Ti-48Al-2Cr- 2Nb, Ti-47Al-2Cr-2Nb, ABB-2, ABB-23, NCG359E, 95A and Ti-45Al-5Nb-B-C was accessed. Differences in the ballistic impact properties of the various alloys will be discussed, particularly with respect to their manufacturing process, microstructure, and tensile properties.

  19. Sporadic and hereditary amyotrophic lateral sclerosis (ALS).

    PubMed

    Ajroud-Driss, Senda; Siddique, Teepu

    2015-04-01

    Genetic discoveries in ALS have a significant impact on deciphering molecular mechanisms of motor neuron degeneration. The identification of SOD1 as the first genetic cause of ALS led to the engineering of the SOD1 mouse, the backbone of ALS research, and set the stage for future genetic breakthroughs. In addition, careful analysis of ALS pathology added valuable pieces to the ALS puzzle. From this joint effort, major pathogenic pathways emerged. Whereas the study of TDP43, FUS and C9ORF72 pointed to the possible involvement of RNA biology in motor neuron survival, recent work on P62 and UBQLN2 refocused research on protein degradation pathways. Despite all these efforts, the etiology of most cases of sporadic ALS remains elusive. Newly acquired genomic tools now allow the identification of genetic and epigenetic factors that can either increase ALS risk or modulate disease phenotype. These developments will certainly allow for better disease modeling to identify novel therapeutic targets for ALS. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.

  20. Presymptomatic ALS genetic counseling and testing

    PubMed Central

    Stanislaw, Christine; Reyes, Eliana; Hussain, Sumaira; Cooley, Anne; Fernandez, Maria Catalina; Dauphin, Danielle D.; Michon, Sara-Claude; Andersen, Peter M.; Wuu, Joanne

    2016-01-01

    Remarkable advances in our understanding of the genetic contributions to amyotrophic lateral sclerosis (ALS) have sparked discussion and debate about whether clinical genetic testing should routinely be offered to patients with ALS. A related, but distinct, question is whether presymptomatic genetic testing should be offered to family members who may be at risk for developing ALS. Existing guidelines for presymptomatic counseling and testing are mostly based on small number of individuals, clinical judgment, and experience from other neurodegenerative disorders. Over the course of the last 8 years, we have provided testing and 317 genetic counseling sessions (including predecision, pretest, posttest, and ad hoc counseling) to 161 first-degree family members participating in the Pre-Symptomatic Familial ALS Study (Pre-fALS), as well as testing and 75 posttest counseling sessions to 63 individuals with familial ALS. Based on this experience, and the real-world challenges we have had to overcome in the process, we recommend an updated set of guidelines for providing presymptomatic genetic counseling and testing to people at high genetic risk for developing ALS. These recommendations are especially timely and relevant given the growing interest in studying presymptomatic ALS. PMID:27194384

  1. Quantitatively probing the Al distribution in zeolites.

    PubMed

    Vjunov, Aleksei; Fulton, John L; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K; Govind, Niranjan; Camaioni, Donald M; Hu, Jian Zhi; Lercher, Johannes A

    2014-06-11

    The degree of substitution of Si(4+) by Al(3+) in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. Because the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and (27)Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations, allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in an HBEA150 zeolite has been determined using this analysis.

  2. 75 FR 62858 - United States, et al.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Antitrust Division United States, et al. v. American Express Company, et al.; Proposed Final Judgment and Competitive Impact Statement Notice is hereby given pursuant to the Antitrust Procedures and Penalties Act, 15 U.S.C. 16(b)-(h), that a proposed...

  3. Quantitatively Probing the Al Distribution in Zeolites

    SciTech Connect

    Vjunov, Aleksei; Fulton, John L.; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K.; Govind, Niranjan; Camaioni, Donald M.; Hu, Jian Z.; Lercher, Johannes A.

    2014-06-11

    The degree of substitution of Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. As the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and 27Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al-distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in the HBEA150 sample has been determined from a combination of these methods. This work was supported by the U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  4. Energetics of Al13 Keggin cluster compounds

    PubMed Central

    Armstrong, Christopher R.; Casey, William H.; Navrotsky, Alexandra

    2011-01-01

    The ϵ-Al13 Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ϵ-Keggin clusters, Al13 selenate, (Na(AlO4)Al12(OH)24(SeO4)4•12H2O) and Al13 sulfate, (NaAlO4Al12(OH)24(SO4)4•12H2O). The measured enthalpies of solution, ΔHsol, at 28 °C in 5 N HCl for the ε-Al13 selenate and sulfate are −924.57 (± 3.83) and −944.30 ( ± 5.66) kJ·mol-1, respectively. The enthalpies of formation from the elements, ΔHf,el, for Al13 selenate and sulfate are −19,656.35 ( ± 67.30) kJ·mol-1, and −20,892.39 ( ± 70.01) kJ·mol-1, respectively. In addition, ΔHf,el for sodium selenate decahydrate was calculated using data from high temperature oxide melt solution calorimetry measurements: −4,006.39 ( ± 11.91) kJ·mol-1. The formation of both ε-Al13 Keggin cluster compounds is exothermic from oxide-based components but energetically unfavorable with respect to a gibbsite-based assemblage. To understand the relative affinity of the ϵ-Keggin clusters for selenate and sulfate, the enthalpy associated with two S-Se exchange reactions was calculated. In the solid state, selenium is favored in the Al13 compound relative to the binary chalcogenate, while in 5 N HCl, sulfur is energetically favored in the cluster compound compared to the aqueous solution. This contribution represents the first thermodynamic study of ε-Al13 cluster compounds and establishes a method for other such molecules, including the substituted versions that have been created for kinetic studies. Underscoring the importance of ε-Al13 clusters in natural and anthropogenic systems, these data provide conclusive thermodynamic evidence that the Al13 Keggin cluster is a crucial intermediate species in the formation pathway from aqueous aluminum monomers to aluminum hydroxide precipitates. PMID:21852572

  5. Si Purification by Removal of Entrapped Al during Electromagnetic Solidification Refining of Si-Al Alloy

    NASA Astrophysics Data System (ADS)

    Yu, Wenzhou; Ma, Wenhui; Zheng, Zhong; Lei, Yun; Jiang, Weiyan; Li, Jie

    2017-10-01

    To investigate the effect of the removal of entrapped Al on Si purity during Al-Si electromagnetic solidification refining, the formation mechanism and removal principle of entrapped Al in primary Si were studied. The results showed that the agglomeration and irregular shape of primary Si crystals during electromagnetic solidification were the main reasons for the formation of entrapped Al; a higher initial Si content in an Al-Si alloy may result in higher amounts of entrapped Al. The entrapped Al can be effectively removed by first grinding the primary Si to powder particles of 20 μm and then leaching the particles with acid, which can simultaneously remove other impurities concentrated in the entrapped Al such as Fe, Ca, Ti, and B. Hence, it is proposed that the combination of electromagnetic solidification, acid leaching, and vacuum directional solidification could be used to obtain solar-grade silicon.

  6. Si Purification by Removal of Entrapped Al during Electromagnetic Solidification Refining of Si-Al Alloy

    NASA Astrophysics Data System (ADS)

    Yu, Wenzhou; Ma, Wenhui; Zheng, Zhong; Lei, Yun; Jiang, Weiyan; Li, Jie

    2017-06-01

    To investigate the effect of the removal of entrapped Al on Si purity during Al-Si electromagnetic solidification refining, the formation mechanism and removal principle of entrapped Al in primary Si were studied. The results showed that the agglomeration and irregular shape of primary Si crystals during electromagnetic solidification were the main reasons for the formation of entrapped Al; a higher initial Si content in an Al-Si alloy may result in higher amounts of entrapped Al. The entrapped Al can be effectively removed by first grinding the primary Si to powder particles of 20 μm and then leaching the particles with acid, which can simultaneously remove other impurities concentrated in the entrapped Al such as Fe, Ca, Ti, and B. Hence, it is proposed that the combination of electromagnetic solidification, acid leaching, and vacuum directional solidification could be used to obtain solar-grade silicon.

  7. Dose-enhancement effects in TaSi/Al- and Al-gate MOS devices

    SciTech Connect

    Fleetwood, D.M.; Beutler, D.E.; Draper, B.L.; Knott, D.; Brown, D.B.; Rosenstock, H.

    1988-01-01

    The response of MOS capacitors with TaSi/Al and Al electrodes to medium- and low-energy x-irradiation is investigated. Experimentally measured dose-enhancement effects are compared with computer simulations for these structures.

  8. NiAl alloys for structural uses

    NASA Technical Reports Server (NTRS)

    Koss, D. A.

    1991-01-01

    Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the

  9. Phase stability in binary Ti-Al

    NASA Technical Reports Server (NTRS)

    Anderson, C. D.; Hofmeister, W. H.; Bayuzick, R. J.

    1991-01-01

    Binary Ti-Al samples containing from 46 to 54 at. pct Al were solidified while undercooled by various amounts using electromagnetic levitation techniques. A detailed thermal history of these samples was obtained with sampling rates as high as 500 KHz during recalescence. This very high sampling rate was essential to resolve the thermal events. Primary alpha solidification was observed in samples containing from 51 to 54 at. pct Al that were undercooled less than about 100 K at solidification. Primary beta solidification was found for all undercoolings tested in samples containing less than 51 at. pct Al and for undercoolings greater than about 100 K in samples containing 51 to 54 at. pct Al.

  10. The neuropathology of FTD associated With ALS.

    PubMed

    Mackenzie, Ian R A

    2007-01-01

    There is increasing recognition of a clinical overlap between frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Recent advances in our understanding of the neuropathologic, biochemical, and genetic basis of these conditions provides evidence for a common underlying pathogenesis. The neuropathology in most cases of FTD with ALS is a subtype of frontotemporal lobar degeneration, characterized by neuronal inclusions that are immunoreactive for ubiquitin but not tau (frontotemporal lobar degeneration with ubiquitinated inclusions). These cases show significant pathologic overlap with clinically pure FTD and those with classic ALS. Moreover, the ubiquitinated pathologic protein in all these conditions has recently been identified as TDP-43. A number of families have been reported with autosomal dominant FTD-ALS linked to chromosome 9p and these also have TDP-43-positive frontotemporal lobar degeneration with ubiquitinated inclusions pathology. Together, these findings suggest that FTD-ALS is part of a clinicopathologic spectrum of disease, now identified as TDP-43 proteinopathies.

  11. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH{sub 2}(Al)

    SciTech Connect

    An, Yang; Li, Huiliang; Liu, Yuanyuan; Huang, Baibiao; Sun, Qilong; Dai, Ying; Qin, Xiaoyan; Zhang, Xiaoyang

    2016-01-15

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH{sub 2} (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO{sub 6}-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs. - Graphical abstract: The photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water of two Al based MOFs were investigated. A new photocatalytic mechanism was proposed based on electron tunneling according to the results of both theoretical calculation and steady state, time resolved fluorescence spectra. The electron tunneling process not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.

  12. High temperature creep behaviour of Al-rich Ti-Al alloys

    NASA Astrophysics Data System (ADS)

    Sturm, D.; Heilmaier, M.; Saage, H.; Aguilar, J.; Schmitz, G. J.; Drevermann, A.; Palm, M.; Stein, F.; Engberding, N.; Kelm, K.; Irsen, S.

    2010-07-01

    Compared to Ti-rich γ-TiAl-based alloys Al-rich Ti-Al alloys offer an additional reduction of in density and a better oxidation resistance which are both due to the increased Al content. Polycrystalline material was manufactured by centrifugal casting. Microstructural characterization was carried out employing light-optical, scanning and transmission electron microscopy and XRD analyses. The high temperature creep of two binary alloys, namely Al60Ti40 and Al62Ti38 was comparatively assessed with compression tests at constant true stress in a temperature range between 1173 and 1323 K in air. The alloys were tested in the cast condition (containing various amounts of the metastable phases Al5Ti3 and h-Al2Ti) and after annealing at 1223 K for 200 h which produced (thermodynamically stable) lamellar γ-TiAl + r-Al2Ti microstructures. In general, already the as-cast alloys exhibit a reasonable creep resistance at 1173 K. Compared with Al60Ti40, both, the as-cast and the annealed Al62Ti38 alloy exhibit better creep resistance up to 1323 K which can be rationalized by the reduced lamella spacing. The assessment of creep tests conducted at identical stress levels and varying temperatures yielded apparent activation energies for creep of Q = 430 kJ/mol for the annealed Al60Ti40 alloy and of Q = 383 kJ/mol for the annealed Al62Ti38 material. The latter coincides well with that of Al diffusion in γ-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

  13. Microstructure and Mechanical Properties of Al-AL4C3 Materials

    DTIC Science & Technology

    2004-03-18

    MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AL- AL4C3 MATERIALS Michal BESTERCI, Ľudovít PARILÁK Institute of Materials Research, Slovak Academy of...Carbon transformation to carbide Al4C3 is characterised for different heat treatment schedules and nine commercial carbon powders tested. The...transformed dispersed phase Al4C3 is than produced by a chemical reaction, which starts during milling, and it is completed at the next heat treatment

  14. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  15. Draft Genome Sequences of the Aerobic Strains Lactobacillus gasseri AL3 and AL5.

    PubMed

    Maresca, Diamante; De Filippis, Francesca; Tytgat, Hanne L P; de Vos, Willem M; Mauriello, Gianluigi

    2017-05-04

    Adaptation to the aerobic environment has been investigated in heterofermentative lactobacilli, while data on how homofermentative lactobacilli adapt to oxygen are limited. We report here the draft genome sequences of the aerobic strains Lactobacillus gasseri AL3 and AL5 that allow an in-depth investigation of the genes involved in oxidative metabolism and the stress response. Copyright © 2017 Maresca et al.

  16. Bedside Teaching: general and discipline-specific teacher characteristics, criteria for patient selection and difficulties.

    PubMed

    Dybowski, Christoph; Harendza, Sigrid

    2013-01-01

    Zielsetzung: Zum Unterricht am Krankenbett (UaK), dem in der medizinischen Ausbildung eine wichtige Funktion für das Üben von Anamnese und klinischer Untersuchung zukommt, finden sich bisher nur wenige Untersuchungen, die Empfehlungen für die Gestaltung definieren. In Evaluationen wird jedoch vielfach über Schwierigkeiten mit dieser Unterrichtsform berichtet. Ziel der Studie ist es daher, wichtige Rahmenbedingungen für den UaK zu erheben und wesentliche Aspekte für die Patientenauswahl zu identifizieren.Methodik: Ein neu konzipierter Fragebogen mit geschlossenen und offenen Fragen zur Organisation des UaK, der Durchführung und Ausgestaltung sowie der Patientenauswahl wurde an insgesamt 134 Dozierende der Fächer Chirurgie, Innere Medizin und Psychiatrie verschickt. Die erhobenen Daten wurden quantitativ und qualitativ ausgewertet.Ergebnisse: Dozierende der Inneren Medizin waren signifikant älter als Dozierende der anderen beiden Fächer. In der Chirurgie wurde ein signifikant größerer Anteil der Termine von jüngeren Assistenzärzten unterrichtet. Die Einwilligung der Patienten und die Passung ihrer Erkrankungen zu den Lernzielen wurden fächerübergreifend als die wichtigsten Faktoren für die Patientenauswahl angegeben. Psychiater maßen gegenüber Chirurgen nach eigenen Angaben guten Deutschkenntnissen der Patienten signifikant mehr Bedeutung zu. In der Chirurgie wurde ein akut schlechter Gesundheitszustand tendenziell häufiger als Ausschlusskriterium der Patienten vom UaK genannt.Schlussfolgerung: Für die inhaltliche und organisatorische Planung und für die Patientenauswahl des UaK sollten die von den Dozenten benannten Aspekte und die fächerspezifischen Besonderheiten für die Planung des UaK berücksichtigt und bei Dozentenschulungen thematisiert werden.

  17. Japanese version of the ALS-FTD-Questionnaire (ALS-FTD-Q-J).

    PubMed

    Watanabe, Yasuhiro; Beeldman, Emma; Raaphorst, Joost; Izumi, Yuishin; Yoshino, Hiide; Masuda, Michihito; Atsuta, Naoki; Ito, Satoru; Adachi, Tadashi; Adachi, Yoshiki; Yokota, Osamu; Oda, Masaya; Hanashima, Ritsuko; Ogino, Mieko; Ichikawa, Hiroo; Hasegawa, Kazuko; Kimura, Hideki; Shimizu, Toshio; Aiba, Ikuko; Yabe, Hayato; Kanba, Makoto; Kusumi, Kimiyoshi; Aoki, Tetsuya; Hiroe, Yu; Watanabe, Hirohisa; Nishiyama, Kazutoshi; Nomoto, Masahiro; Sobue, Gen; Nakashima, Kenji

    2016-08-15

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share common clinical, genetic and neuropathological features. Some ALS patients have behavioral/personality changes, which could result in significant obstacles in the care provided by family members and caregivers. An easy screening tool would contribute greatly to the evaluation of these symptoms. We translated the ALS-FTD-Questionnaire, developed in the Netherlands, into Japanese (ALS-FTD-Q-J) and examined the clinimetric properties (internal consistency, construct and clinical validity). Patients with ALS and/or behavioral variant FTD (bvFTD) were evaluated alongside healthy controls in this multicenter study. All ALS patients, regardless of bvFTD status, were further evaluated by the frontal behavioral inventory (FBI) and for frontal/executive function, cognition, anxiety/depression, and motor functions. Data from 146 subjects were analyzed: ALS (92), ALS-bvFTD (6), bvFTD (16), and healthy controls (32). The internal consistency of the ALS-FTD-Q-J was good (Cronbach α=0.92). The ALS-FTD-Q-J showed construct validity as it exhibited a high correlation with the FBI (r=0.79). However, correlations were moderate with anxiety/depression and low with cognitive scales, in contrast to the original report, i.e. a moderate correlation with cognition and a low correlation with anxiety/depression. The ALS-FTD-Q-J discriminated ALS patients from (ALS-)bvFTD patients and controls. Thus, the ALS-FTD-Q-J is useful for evaluating Japanese ALS/FTD patients.

  18. Alanes formation on the Al(111) surface

    NASA Astrophysics Data System (ADS)

    Rangan, Sylvie; Veyan, Jean-Francois; Chabal, Yves J.; Chaudhuri, Santanu; Muckerman, James T.

    2008-03-01

    Alane clusters (AlxHy) are believed to be the ubiquitous intermediates in hydrogen storage reactions for a wide variety of alanates (LiAlH4, NaAlH4) currently considered for hydrogen storage. The formation and behavior of alanes at surfaces appear to control and limit the efficiency of hydrogen storage. In particular, hydrogen adsorption on the Al(111) surface leads to the coexistence of several adsorbed species, the concentration of which is affected by the step density, the surface coverage and the temperature. We combine density functional theory (DFT) and surface infra-red (IR) absorption spectroscopy to uncover the mechanisms for alane formation on Al(111) surfaces. At low coverage, DFT predicts a two-fold bridge site adsorption for atomic hydrogen, consistent with previous Electron Energy Loss Spectroscopy measurements. At higher coverage, the formation of small chemisorbed AlH3 occurs at the step edges. With increasing coverage AlH3 is extracted from the step edge and becomes highly mobile on the terraces in a weakly bound state. This mobility is the key factor leading to the growth of larger alanes through AlH3 oligomerization. For these large alanes, previous Thermal Programmed Desorption studies are discussed and compared to the thermal stability observed in IR.

  19. Effects of hydrogen absorption in TbNiAl and UNiAl

    SciTech Connect

    Bordallo, H.N.; Nakotte, H.; Schultz, A.; Kolomiets, A.V.; Havela, L.; Andreev, A.V.

    1998-12-31

    Although hydrides of intermetallic compounds are used extensively as hydrogen-storage media, little is known about the exact nature of metal-hydrogen interactions. However, this knowledge is of essential importance for the understanding of thermodynamics and other properties. Hydrides (deuterides) of TbNiAl and UNiAl have been widely studied because of drastic increase of magnetic ordering temperature under hydrogenation. Here the authors report neutron-diffraction results of the three deuterides, TbNiAlD{sub 1.28}, TbNiAlD{sub 0.8}a nd UNiAlD{sub 2.23}.

  20. Phase stability and microstructure of Al-Ti-Fe near Al{sub 3}Ti

    SciTech Connect

    Yang, T.Y.; Goo, E.

    1995-05-01

    The phase stability and microstructure of Al-Ti-Fe near Al{sub 3}Ti at 800 C are studied by using high resolution electron microscopy and backscattered electron imaging. One of the most significant changes resulting from the addition of small amounts of iron in this system is to convert tetragonal Al{sub 3}Ti or Al{sub 2}Ti into cubic Ll{sub 2} structures. In addition, the added iron can change the stacking structure of Al{sub 2}Ti and the domain size of the long-period one-dimensional antiphase domain structures. A partial ternary phase diagram in this region is also determined.

  1. Atomistic Modeling of RuAl and (RuNi) Al Alloys

    NASA Technical Reports Server (NTRS)

    Gargano, Pablo; Mosca, Hugo; Bozzolo, Guillermo; Noebe, Ronald D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Atomistic modeling of RuAl and RuAlNi alloys, using the BFS (Bozzolo-Ferrante-Smith) method for alloys is performed. The lattice parameter and energy of formation of B2 RuAl as a function of stoichiometry and the lattice parameter of (Ru(sub 50-x)Ni(sub x)Al(sub 50)) alloys as a function of Ni concentration are computed. BFS based Monte Carlo simulations indicate that compositions close to Ru25Ni25Al50 are single phase with no obvious evidence of a miscibility gap and separation of the individual B2 phases.

  2. A new discontinuously reinforced aluminum MMC: Al+AlB{sub 2} flakes

    SciTech Connect

    HALL,AARON C.; ECONOMY,J.

    2000-06-08

    Development of a novel metal matrix composite based on the Al-B alloy system has been undertaken. Preparation of this discontinuously reinforced material is based on the precipitation of high aspect ratio AlB{sub 2} from an Al-B alloy. This paper describes a number of efforts forced on preparing high volume fractions (> 30 v%) of AlB{sub 2} in aluminum. New insights into the behavior of the Al-B alloys system allowed this effort to be successful.

  3. Phase diagrams of Al-Si and Al-Ge systems

    NASA Astrophysics Data System (ADS)

    Kagaya, Hiroko-Matsuo; Imazawa, Kazumoto; Sato, Mayumi; Soma, Toshinobu

    1998-03-01

    Considering the contributions from the band and local mode frequencies, the temperature- and pressure-dependent mean-square displacement for Al-Si and Al-Ge solid solutions is quantitatively calculated to be similar to that for matrix Al. Then, the concentration-dependence of the Debye temperature at higher and lower temperatures is estimated, the pressure effect on the solidus curve is presented by applying Lindeman's melting law to the Al-Si and Al-Ge alloy systems. The solidus curve obtained increases as a function of the pressure, and is in good agreement with the observed tendency for these solid solutions.

  4. Decoding ALS: from genes to mechanism.

    PubMed

    Taylor, J Paul; Brown, Robert H; Cleveland, Don W

    2016-11-10

    Amyotrophic lateral sclerosis (ALS) is a progressive and uniformly fatal neurodegenerative disease. A plethora of genetic factors have been identified that drive the degeneration of motor neurons in ALS, increase susceptibility to the disease or influence the rate of its progression. Emerging themes include dysfunction in RNA metabolism and protein homeostasis, with specific defects in nucleocytoplasmic trafficking, the induction of stress at the endoplasmic reticulum and impaired dynamics of ribonucleoprotein bodies such as RNA granules that assemble through liquid-liquid phase separation. Extraordinary progress in understanding the biology of ALS provides new reasons for optimism that meaningful therapies will be identified.

  5. Ni{sub 3}Al aluminide alloys

    SciTech Connect

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  6. Arsenate uptake by Al nanoclusters and other Al-based sorbents during water treatment.

    PubMed

    Mertens, Jasmin; Rose, Jérôme; Wehrli, Bernhard; Furrer, Gerhard

    2016-01-01

    In many parts of the world, arsenic from geogenic and anthropogenic sources deteriorates the quality of drinking water resources. Effective methods of arsenic removal include adsorption and coagulation with iron- and aluminum-based materials, of which polyaluminum chloride is widely employed as coagulant in water treatment due to its low cost and high efficiency. We compared the arsenic uptake capacity and the arsenic bonding sites of different Al-based sorbents, including Al nanoclusters, polyaluminum chloride, polyaluminum granulate, and gibbsite. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that As(V) forms bidentate-binuclear complexes in interaction with all Al-based removal agents. The octahedral configuration of nanoclusters and the distribution of sorption sites remain the same in all types of removal agents consisting of nano-scale Al oxyhydroxide particles. The obtained distances for As(V)-O and As(V)-Al agreed with previously published data and were found to be 1.69 ± 0.02 Å and 3.17-3.21 Å, respectively. Our study suggests that As(V) binds to Al nanoclusters as strongly as to Al oxide surfaces. The As sorption capacity of Al nanoclusters was found to be very similar to that of Al clusters in a polyaluminum chloride. The most efficient Al-based sorbents for arsenic removal were Al nanoclusters, followed by polyaluminum granulate.

  7. Morphology of AlN whiskers grown by reacting N2 gas and Al vapor

    NASA Astrophysics Data System (ADS)

    Matsumoto, M.; Saitou, H.; Takeuchi, Y.; Harada, S.; Tagawa, M.; Ujihara, T.

    2017-06-01

    We have investigated the morphology of AlN whiskers on a polycrystalline AlN substrate by using Fe-Al alloy melts under the different synthesis conditions. Formation density of the AlN whiskers increases and the diameter of the whisker decreases with increasing Al content of the Fe-Al alloy melt. Most of the AlN whiskers were zigzag shape with the hexagonal cross section. The longitudinal direction was the [0001] direction. The facet with the zigzag shape was the {1 1 bar 01} or {1 1 bar 0 1 bar } pyramidal plane and the period of the zigzag facet was almost constant. The average diameter of the whiskers and the period of the zigzag facet decrease with increasing Al content. At the initial stage of the whisker formation, the island of AlN formed on the AlN substrate and the pyramidal facet grows via step-flow growth. From the observation, we discussed the possible mechanism for the formation of the zigzag-shape AlN whiskers.

  8. Al6H18: A baby crystal of γ-AlH3

    NASA Astrophysics Data System (ADS)

    Kiran, B.; Kandalam, Anil K.; Xu, Jing; Ding, Y. H.; Sierka, M.; Bowen, K. H.; Schnöckel, H.

    2012-10-01

    Using global-minima search methods based on the density functional theory calculations of (AlH3)n (n = 1-8) clusters, we show that the growth pattern of alanes for n ≥ 4 is dominated by structures containing hexa-coordinated Al atoms. This is in contrast to the earlier studies where either linear or ring structures of AlH3 were predicted to be the preferred structures in which the Al atoms can have a maximum of five-fold coordination. Our calculations also reveal that the Al6H18 cluster, with its hexa-coordination of the Al atoms, resembles the unit-cell of γ-AlH3, thus Al6H18 is designated as the "baby crystal." The fragmentation energies of the (AlH3)n (n = 2-8) along with the dimerization energies for even n clusters indicate an enhanced stability of the Al6H18 cluster. Both covalent (hybridization) and ionic (charge) contribution to the bonding are the driving factors in stabilizing the isomers containing hexa-coordinated Al atoms.

  9. Al6H18: a baby crystal of γ-AlH3.

    PubMed

    Kiran, B; Kandalam, Anil K; Xu, Jing; Ding, Y H; Sierka, M; Bowen, K H; Schnöckel, H

    2012-10-07

    Using global-minima search methods based on the density functional theory calculations of (AlH(3))(n) (n = 1-8) clusters, we show that the growth pattern of alanes for n ≥ 4 is dominated by structures containing hexa-coordinated Al atoms. This is in contrast to the earlier studies where either linear or ring structures of AlH(3) were predicted to be the preferred structures in which the Al atoms can have a maximum of five-fold coordination. Our calculations also reveal that the Al(6)H(18) cluster, with its hexa-coordination of the Al atoms, resembles the unit-cell of γ-AlH(3), thus Al(6)H(18) is designated as the "baby crystal." The fragmentation energies of the (AlH(3))(n) (n = 2-8) along with the dimerization energies for even n clusters indicate an enhanced stability of the Al(6)H(18) cluster. Both covalent (hybridization) and ionic (charge) contribution to the bonding are the driving factors in stabilizing the isomers containing hexa-coordinated Al atoms.

  10. Oxidation of Al2O3 continuous fiber-reinforced/NiAl composites

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Nesbitt, J. A.; Noebe, R. D.; Bowman, R. R.

    1992-01-01

    The 1200 C and 1300 C isothermal and cyclic oxidation behavior of Al2O3 continuous fiber-reinforced/NiAl composites were studied. Oxidation resulted in formation of Al2O3 external scales in a similar manner as scales formed on monolithic NiAl. The isothermal oxidation of an Al2O3/NiAl composite resulted in oxidation of the matrix along the fiber/matrix interface near the fiber ends. This oxide acted as a wedge between the fiber and the matrix, and, under cyclic oxidation conditions, led to further oxidation along the fiber lengths and eventual cracking of the composite. The oxidation behavior of composites in which the Al2O3 fibers were sputter coated with nickel prior to processing was much more severe. This was attributed to open channels around the fibers which formed during processing, most likely as a result of the diffusion of the nickel coating into the matrix.

  11. InAlN/AlN/GaN heterostructures for high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Usov, S. O.; Sakharov, A. V.; Tsatsulnikov, A. F.; Lundin, V. W.; Zavarin, E. E.; Nikolaev, A. E.; Yagovkina, M. A.; Zemlyakov, V. E.; Egorkin, V. I.; Ustinov, V. M.

    2016-08-01

    The results of development of InAlN/AlN/GaN heterostructures, grown on sapphire substrates by metal-organic chemical vapour deposition, and high electron mobility transistors (HEMTs) based on them are presented. The dependencies of the InAlN/AlN/GaN heterostructure properties on epitaxial growth conditions were investigated. The optimal indium content and InAlN barrier layer thicknesses of the heterostructures for HEMT s were determined. The possibility to improve the characteristics of HEMTs by in-situ passivation by Si3N4 thin protective layer deposited in the same epitaxial process was demonstrated. The InAlN/AlN/GaN heterostructure grown on sapphire substrate with diameter of 100 mm were obtained with sufficiently uniform distribution of sheet resistance. The HEMTs with saturation current of 1600 mA/mm and transconductance of 230 mS/mm are demonstrated.

  12. Effect of Al content on magnetic properties of Fe-Al Non-oriented electrical steel

    NASA Astrophysics Data System (ADS)

    Hong, Jaewan; Choi, Hyunseo; Lee, Seil; Kim, Jae Kwan; Koo, Yang mo

    2017-10-01

    The effects of Al content (0.53 ≤ Al ≤ 9.65 wt%) on microstructure, texture, magnetic flux density, permeability, core loss and magnetic domain structure of Fe-Al based electrical steel were measured or observed. Average grain size decreased as Al content increased, but Al contents had no severe effects on texture. Magnetic flux density and permeability tends to decrease as Al content increased. Total core loss Ptot was separated into hysteresis loss Ph, eddy-current loss Pe and anomalous loss Pa. As Al increased, Ph increased, but Pe and Pa decreased, so the optimal grain size increased. To reduce core loss of electrical steel with high resistivity, annealing should be conducted at high temperature and for a long time to increase grain size.

  13. Contribution to Kinetics of Superplastic Deformation of Dispersion Strengthened Al-Al4C3 System

    NASA Astrophysics Data System (ADS)

    Besterci, Michal; Varchola, Marián; Kováč, Ladislav; Velgosová, Oksana

    2012-02-01

    The influence of temperature at constant strain rate has been evaluated with respect to superplastic behavior of dispersion strengthened Al-Al4C3 composite with 4 vol.% of Al4C3 phase. The dispersion strengthened Al-Al4C3 was prepared by powder metallurgy. Material can be characterized by grain size around 1 μm and dispersed particle Al4C3 size around 50 nm. This material showed superplastic behavior for strain rate 10-3 s-1 by test temperature 573 K. The mechanism of superplastic deformation was also investigated. For the presented material with low content of disperse particle slip on grain boundaries is typical. The final fracture is transcrystalline with dimples with their mean size 1.25 μm. The dimples are initialized by Al4C3 particles in size from 40 to 50 nm.

  14. Oxidation of Al2O3 continuous fiber-reinforced/NiAl composites

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Nesbitt, J. A.; Noebe, R. D.; Bowman, R. R.

    1992-01-01

    The 1200 C and 1300 C isothermal and cyclic oxidation behavior of Al2O3 continuous fiber-reinforced/NiAl composites were studied. Oxidation resulted in formation of Al2O3 external scales in a similar manner as scales formed on monolithic NiAl. The isothermal oxidation of an Al2O3/NiAl composite resulted in oxidation of the matrix along the fiber/matrix interface near the fiber ends. This oxide acted as a wedge between the fiber and the matrix, and, under cyclic oxidation conditions, led to further oxidation along the fiber lengths and eventual cracking of the composite. The oxidation behavior of composites in which the Al2O3 fibers were sputter coated with nickel prior to processing was much more severe. This was attributed to open channels around the fibers which formed during processing, most likely as a result of the diffusion of the nickel coating into the matrix.

  15. Elimination of AlGaN epilayer cracking by spatially patterned AlN mask

    NASA Astrophysics Data System (ADS)

    Sarzyński, Marcin; Kryśko, Marcin; Targowski, Grzegorz; Czernecki, Robert; Sarzyńska, Agnieszka; Libura, Adam; Krupczyński, Wiktor; Perlin, Piotr; Leszczyński, Michał

    2006-03-01

    The inherent problem in III-nitride technology is the cracking of AlGaN layers that results from lattice mismatch between AlGaN and GaN. In case of thin substrates (30-90μm), such as, bulk GaN grown by the high-pressure/high-temperature method, the bowing of AlGaN /GaN strained structures becomes an additional problem. To eliminate cracking and bowing, AlGaN layers were grown on GaN substrates with an AlN mask patterned to form 3-15μm wide windows. In the 3μm window, the AlGaN layer was not cracked, although its thickness and Al composition exceeded critical values for growth on nonpatterned substrates. Dislocation density in the windows was of 5×106/cm2.

  16. Fabrication of Al/Mg/Al Composites via Accumulative Roll Bonding and Their Mechanical Properties

    PubMed Central

    Nie, Jinfeng; Liu, Mingxing; Wang, Fang; Zhao, Yonghao; Li, Yusheng; Cao, Yang; Zhu, Yuntian

    2016-01-01

    Al(1060)/Mg(AZ31)/Al(1060) multilayered composite was successfully produced using an accumulative roll bonding (ARB) process for up to four cycles at an elevated temperature (400 °C). The microstructure evolution of the composites and the bonding characteristics at the interfaces between Al and Mg layers with increasing ARB cycles were characterized through optical microscopy, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). It was found that the grains of Al and Mg layers were significantly refined and Al3Mg2 and Al12 Mg17 intermetallic compound layers formed at the Al/Mg bonding interfaces. The strength increased gradually and the ultimate tensile strength (UTS) reached a maximum value of about 240 MPa at the third pass. Furthermore, the strengthening mechanism of the composite was analyzed based on the fracture morphologies. PMID:28774072

  17. Diffusion at the Al/Al oxide interface during electromigration in wide lines

    NASA Astrophysics Data System (ADS)

    Augur, R. A.; Wolters, R. A. M.; Schmidt, W.; Dirks, A. G.; Kordić, S.

    1996-03-01

    Significant large-scale modification of the surface of Al-Si conductors was observed, due to electromigration in wide lines and under low stress conditions. After electromigration stressing the Al layers showed local thickness variations, i.e., damage by thinning. The mechanism underlying this damage causes substantial metal transport. Nevertheless, damage by thinning has received little attention in the past. Thinning was observed: (1) in a number of different alloys (Al-Si, Al-Cu, Al-Si-V, and Al-Si-V-Pd), (2) with a number of different underlayers [SiO2, W-Ti (no vacuum break after Al deposition) and W-Ti (oxidized surface before Al deposition)], (3) over an extended temperature range, (4) over a range of current density, and (5) in structures with and without passivation. The results show that thinning is a general phenomenon. An activation energy of approximately 0.5 eV was determined for the temperature dependence of a combined mechanism of concurrent thinning plus voiding in Al99Si1. Several alternatives are examined to explain the observations, namely mass movement along dislocations, Al bulk diffusion, and diffusion at the interface between the Al and its oxide. It is shown that diffusion at the Al/Al oxide interface most probably plays an important role in the damage mechanism, even under stress conditions where grain boundary diffusion is traditionally thought to dominate. Results also showed that alloying of Al with Pd can reduce the effects of damage by thinning.

  18. Interdiffusion in Diffusion Couples: U-Mo v. Al and Al-Si

    SciTech Connect

    D. D. Keiser, Jr.; E. Perez; B. Yao; Y. H. Sohn

    2009-11-01

    Interdiffusion and microstructural development in the U-Mo-Al system was examined using solid-tosolid diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo vs. pure Al, annealed at 600°C for 24 hours. The influence of Si alloying addition (up to 5 wt.%) in Al on the interdiffusion microstructural development was also examined using solid-to-solid diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo vs. pure Al, Al-2wt.%Si, and Al-5wt.%Si annealed at 550°C up to 20 hours. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA) were employed to examine the development of a very fine multiphase intermetallic layer. In ternary U-Mo-Al diffusion couples annealed at 600°C for 24 hours, interdiffusion microstructure varied of finely dispersed UAl3, UAl4, U6Mo4Al43, and UMo2Al20 phases while the average composition throughout the interdiffusion zone remained constant at approximately 80 at.% Al. Interdiffusion microstructure observed by SEM/TEM analyses and diffusion paths drawn from concentration profiles determined by EPMA appear to deviate from the assumption of “local thermodynamic equilibrium,” and suggest that interdiffusion occurs via supersaturated UAl4 followed by equilibrium transformation into UAl3, U6Mo4Al43, UAl4 and UMo2Al20 phases. Similar observation was made for U-Mo vs. Al diffusion couples annealed at 550°C. The addition of Si (up to 5 wt.%) in Al significantly reduced the thickness of the intermetallic layer by changing the constituent phases of the interdiffusion zone developed in U-Mo vs. Al-Si diffusion couples. Specifically, the formation of (U,Mo)(Al,Si)3 with relatively large solubility for Mo and Si, along with UMo2Al20 phases was observed along with disappearance of U6Mo4Al43 and UAl4 phases. Simplified understanding based on U-Al, U-Si, and Mo-Si binary phase diagrams is discussed in the light of the beneficial effect of Si alloying addition.

  19. Optical properties of TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO tandem absorber coatings by phase-modulated spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Jyothi, J.; Biswas, A.; Sarkar, P.; Soum-Glaude, A.; Nagaraja, H. S.; Barshilia, Harish C.

    2017-07-01

    TiAlC, TiAlCN, TiAlSiCN, TiAlSiCO, and TiAlSiO layers of thicknesses 2.2 μm, 755, 491, 393, and 431 nm, respectively, were deposited on stainless steel, silicon, and glass substrates to study their refractive indices and extinction coefficients using the phase-modulated spectroscopic ellipsometry in the wavelength range of 300-1200 nm. Absorption coefficient of each layer was calculated from the extinction coefficient of the layer. The results indicate that the first three layers (i.e., TiAlC, TiAlCN, and TiAlSiCN) are absorbing in nature, while TiAlSiCO and TiAlSiO act as intermediate and antireflection layers. Subsequently, a tandem absorber of TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO with layer thicknesses of 62, 20, 18, 16, and 27 nm, respectively, was deposited on stainless steel substrates to fabricate a spectrally selective coating with absorptance of 0.961 and emittance of 0.15 at 82 °C. The obtained refractive indices and extinction coefficients of the tandem absorber were used to simulate the reflectance of the deposited tandem absorber using SCOUT software. Simulated reflectance data of the tandem absorber showed a good agreement with the experimental data measured by UV-Vis-NIR and FTIR spectrophotometry. The angular dependence of the selective properties of the tandem absorber was studied by measuring the reflectance spectra of the tandem absorber at different incident angles.

  20. Pike International, LLC et al. Information Sheet

    EPA Pesticide Factsheets

    Pike International LLC, et al. (the Company) is located in New Haven, Connecticut. The Complaint involves the lease of, and renovation activities conducted at, property constructed prior to 1978, located in New Haven, Connecticut.

  1. Substitutional alloy of Ce and Al

    PubMed Central

    Zeng, Qiao-Shi; Ding, Yang; Mao, Wendy L.; Luo, Wei; Blomqvist, Andreas; Ahuja, Rajeev; Yang, Wenge; Shu, Jinfu; Sinogeikin, Stas V.; Meng, Yue; Brewe, Dale L.; Jiang, Jian-Zhong; Mao, Ho-kwang

    2009-01-01

    The formation of substitutional alloys has been restricted to elements with similar atomic radii and electronegativity. Using high-pressure at 298 K, we synthesized a face-centered cubic disordered alloy of highly dissimilar elements (large Ce and small Al atoms) by compressing the Ce3Al intermetallic compound >15 GPa or the Ce3Al metallic glass >25 GPa. Synchrotron X-ray diffraction, Ce L3-edge absorption spectroscopy, and ab initio calculations revealed that the pressure-induced Kondo volume collapse and 4f electron delocalization of Ce reduced the differences between Ce and Al and brought them within the Hume-Rothery (HR) limit for substitutional alloying. The alloy remained after complete release of pressure, which was also accompanied by the transformation of Ce back to its ambient 4f electron localized state and reversal of the Kondo volume collapse, resulting in a non-HR alloy at ambient conditions. PMID:19188608

  2. 12th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Arthur L.

    1999-12-17

    Science took the front seat as 219 Advanced Light Source (ALS) users and staff gathered on Monday and Tuesday, October 18 and 19 for the twelfth annual users' meeting. The bulk of the meeting was dedicated to reports on science at the ALS. Packed into two busy days were 31 invited oral presentations and 80 submitted poster presentations, as well as time to visit 24 vendor booths. The oral sessions were dedicated to environmental science, chemical dynamics, biosciences, magnetic materials, and atomic and molecular science. In addition, there was an ALS highlights session that emphasized new results and a session comprising highlights from the young scientists who will carry the ALS into the future.

  3. ALS and Oxidative Stress: The Neurovascular Scenario

    PubMed Central

    Thakur, Keshav; Gupta, Pawan Kumar

    2013-01-01

    Oxidative stress and angiogenic factors have been placed as the prime focus of scientific investigations after an establishment of link between vascular endothelial growth factor promoter (VEGF), hypoxia, and amyotrophic lateral sclerosis (ALS) pathogenesis. Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter and mutant superoxide dismutase 1 (SOD1) which are characterised by atrophy and muscle weakness resulted in phenotype resembling human ALS in mice. This results in lower motor neurodegeneration thus establishing an important link between motor neuron degeneration, vasculature, and angiogenic molecules. In this review, we have presented human, animal, and in vitro studies which suggest that molecules like VEGF have a therapeutic, diagnostic, and prognostic potential in ALS. Involvement of vascular growth factors and hypoxia response elements also highlights the converging role of oxidative stress and neurovascular network for understanding and treatment of various neurodegenerative disorders like ALS. PMID:24367722

  4. Half life of /sup 26/Al

    SciTech Connect

    Norris, T.L.; Gancarz, A.J.; Rokop, D.J.; Thomas, K.W.

    1983-01-01

    The half-life of /sup 26/Al has been redetermined because of suggestions of an error in the accepted value based on its use in calculating /sup 21/Ne production rates from cosmic rays in meteorites. Two solutions of /sup 26/Al were analyzed for the specific radioactivity and mass spectrometric determination of the /sup 26/Al concentration. The half-life obtained for /sup 26/Al was 7.05 x 10/sup 5/ years +- 3.7% at the two sigma level. This is identical to the accepted value of 7.16 x 10/sup 5/ years and indicates that problems with the /sup 21/Ne production rate is not due to an erroneous half-life.

  5. On Dobbert et al, 'Cultural Transmission...'

    ERIC Educational Resources Information Center

    Gearing, Frederick

    1984-01-01

    Criticizes Dobbert et al's model of cultural transmission (presented in earlier article) as being a species of social physics. Suggests improvements to the model, notably that observation and analysis at the emic level be taken into account. (RDN)

  6. Rogue Genes May Cause Some ALS Cases

    MedlinePlus

    ... known family history of the disease and a control group of 324 people without ALS. When researchers looked ... four times as likely as those in the control group to have rare and likely harmful gene variants -- ...

  7. On Dobbert et al, 'Cultural Transmission...'

    ERIC Educational Resources Information Center

    Gearing, Frederick

    1984-01-01

    Criticizes Dobbert et al's model of cultural transmission (presented in earlier article) as being a species of social physics. Suggests improvements to the model, notably that observation and analysis at the emic level be taken into account. (RDN)

  8. Cd ion implantation in AlN

    NASA Astrophysics Data System (ADS)

    Miranda, S. M. C.; Franco, N.; Alves, E.; Lorenz, K.

    2012-10-01

    AlN thin films were implanted with cadmium, to fluences of 1 × 1013 and 8 × 1014 at/cm2. The implanted samples were annealed at 950 °C under flowing nitrogen. Although implantation damage in AlN is known to be extremely stable the crystal could be fully recovered at low fluences. At high fluences the implantation damage was only partially removed. Implantation defects cause an expansion of the c-lattice parameter. For the high fluence sample the lattice site location of the ions was studied by Rutherford Backscattering/Channelling Spectrometry. Cd ions are found to be incorporated in substitutional Al sites in the crystal and no significant diffusion is seen upon thermal annealing. The observed high solubility limit and site stability are prerequisite for using Cd as p-type dopant in AlN.

  9. Innovative Al Damascene Process for Nanoscale Interconnects

    NASA Astrophysics Data System (ADS)

    Choi, Kyung‑In; Han, Sung‑Ho; Yun, Sera; Kim, Dae‑Yong; Hong, Jong Won; Lee, Sang Woo; Kim, Byung Hee; Kim, Sung‑Tae; Chung, U‑In; Moon, Joo‑Tae; Ryu, Byung‑Il

    2006-04-01

    A novel chemical vapor deposition (CVD)-Al technique of “bottom-up growth” was developed using methylpyrrolidine alane as a precursor and a (PVD)-TiN/CVD-TiN stacked barrier in a damascene structure. Poor step coverage of PVD-TiN caused an absence of PVD-TiN at the bottom of trenches, resulting in selective Al growth. The new method filled a 40-nm-wide trench (aspect ratio = 7.5) completely and showed robust electrical properties. The lowest line resistance was obtained at a stacked layer of PVD-TiN/CVD-Ru due to the low resistivity of Ru. Furthermore, the fine Al line structure fabricated by the new technique revealed that the Al line structure did not suffer severely from the size effect, which started to affect Cu damascene structures that were 50 nm wide.

  10. Patterns of inheritance in familial ALS.

    PubMed

    Bradley, Marcus; Bradley, Lloyd; de Belleroche, Jackie; Orrell, Richard W

    2005-05-10

    We investigated 185 families with ALS for evidence of anticipation and mitochondrial inheritance. Although initial analysis demonstrated significant anticipation of age at death between generations in patients with familial ALS, further analysis demonstrated features of regression to the mean, suggesting that the perceived differences are the result of bias. In addition, there was no evidence of an effect of preferential maternal inheritance, which would have supported transmission of mitochondrial DNA mutations.

  11. 17th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2004-11-29

    It's not exactly Russian roulette, but scheduling October events outdoors is not risk-free, even in usually sunny California. An overflow crowd of more than 400 registered users, ALS staff, and vendors enjoyed a full indoor program featuring science highlights and workshops spread over two and a half days from October 18 to October 20. However, a major storm, heralding the onset of the San Francisco Bay Area rainy season, posed a few weather challenges for the events on the ALS patio.

  12. Modeling of precipitation in Al alloys

    SciTech Connect

    Asta, M.; Foiles, S.M.; Wolfer, W.G.

    1996-10-01

    Objective was the development of a computational model of precipitation from a supersaturated alloy solid solution. The model is based on the formalism of chemical-reaction-rate theory combined with classical descriptions of precipitate thermodynamic properties and a mean-field treatment of diffusion-limited growht and coarsening. For the case of precipitation of Al{sub 3}Sc in supersaturated Al-Sc alloys, it is demonstrated how the model can be used to calculate number densities and size distributions of precipitates as a function of aging time and temperature, including effects of continuous cooling and thermally generated point defects. Application of the model to a specific alloy system requires knowledge of diffusion data, point defect energetics, and thermodynamic properties for bulk phases and interphase interfaces. For interfaces and point defects, thermodynamic data can be difficult to measure and reliable values of defect free energies are often unavailable. For this reason, part of the efforts were devoted to applying semiempirical and first-principles atomistic techniques to the calculation of interfacial and point-defect thermodynamic properties. This report discusses applications for interphase interfaces in the Al-Ag, Al-Sc, and Al-Li alloy systems. We also describe atomistic work aimed at understanding the energetics of vacancy clusters in Al. These clusters serve as sinks for isolated vacancies during aging and their growth can lead to more complex defects, such as dislocation loops, that act as heterogeneous nucleation sites.

  13. How common are ALS plateaus and reversals?

    PubMed

    Bedlack, Richard S; Vaughan, Timothy; Wicks, Paul; Heywood, Jamie; Sinani, Ervin; Selsov, Roger; Macklin, Eric A; Schoenfeld, David; Cudkowicz, Merit; Sherman, Alex

    2016-03-01

    To determine the frequency of amyotrophic lateral sclerosis (ALS) plateaus and reversals in the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database. We analyzed Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and ALSFRS-revised (ALSFRS-R) data from PRO-ACT participants. The frequencies of participants experiencing plateaus (periods where scores did not change) were calculated over 6-, 12-, and 18-month epochs. The percentage of participants ever experiencing reversals (periods where scores improved) of different lengths were also calculated and plotted. Over 6 months, 25% of 3,132 participants did not decline. Over 12 months, 16% of 2,105 participants did not decline. Over 18 months, 7% of 1,218 participants did not decline. Small ALS reversals were also common, especially over shorter follow-up intervals; 14% of 1,343 participants had a 180-day interval where their ALSFRS-R slope was greater than zero. Fewer than 1% of participants ever experienced improvements of 4 or more ALSFRS-R points lasting at least 12 months. ALS plateaus and small reversals are common, especially over brief intervals. In light of these data, stable disease, especially for a short period of time, should not be interpreted as an ALS treatment effect. Large sustained ALS reversals, on the other hand, are rare, potentially important, and warrant further study. © 2015 American Academy of Neurology.

  14. Unusual Properties of Al_2H_6

    NASA Astrophysics Data System (ADS)

    Ganteför, G.; Burkart, S.; Seifert, G.; Rao, B. K.; Jena, P.

    2000-03-01

    Ab initio calculations based on density functional theory and generalized gradient approximation reveal the structure of Al_2H6 to be that of di-borane (B_2H_6) even though the chemistry of Al and B clusters are different. With an electron affinity of 0.44 eV and ionization potential of 10.14 eV, Al_2H6 bears the signature of a "magic" cluster. Unlike magic clusters in metallic systems, Al_2H6 is born out of the coalescence of two AlH3 which are also "magic" by themselves as dictated by their low electron affinity (0.28 eV) and high ionization potential (11.43 eV). The most striking property of Al_2H_6, however, is that its vertical electron detachment energy is about 2 eV higher than its adiabatic electron affinity signifying vast changes between the geometries of the anion and the neutral cluster. These predictions are verified experimentally by photodetachment spectroscopy.

  15. Theoretics-directed effect of copper or aluminum content on the ductility characteristics of Al-based (Al3Ti, AlTi, AlCu, AlTiCu2) intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Li, Yong; Ma, Xiao-Juan; Liu, Qi-Jun; Kong, Ge-Xing; Ma, Hai-Xia; Wang, Wen-Peng; Wang, Yi-Gao; Jiao, Zhen; Liu, Fu-Sheng; Liu, Zheng-Tang

    2016-11-01

    First-principle simulations have been applied to investigate the effect of copper (Cu) or aluminum (Al) content on the ductility of Al3Ti, AlTi, AlCu, and AlTiCu2 alloys. The mechanical stable and elastic properties of Al-based intermetallic compounds are researched by density functional theory with the generalized gradient approximation (DFT-GGA). The calculated lattice constants are in conformity with the previous experimental and theoretical data. The deduced elastic constants show that the investigated Al3Ti, AlTi, AlCu, and AlTiCu2 structures are mechanically stable. Shear modulus, Young’s modulus, Poisson’s ratio, and the ratio B/G have also been figured out by using reckoned elastic constants. A further analysis of Young’s modulus and Poisson’s ratio reveals that the third added element copper content has significant effects on the Al-Ti-based ICs ductile character. Project supported by the National Natural Science Foundation of China (Grant Nos. 41674088, 11574254, 11272296, and 11547311), the National Basic Research Program of China (Grant No. 2011CB808201), the Fundamental Research Fund for the Central Universities, China (Grant Nos. 2682014ZT30 and 2682014ZT31), and the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University, China (Grant No. SKLSP201511).

  16. Brain FDG-PET changes in ALS and ALS-FTD.

    PubMed

    Renard, Dimitri; Collombier, Laurent; Castelnovo, Giovanni; Fourcade, Genevieve; Kotzki, Pierre-Olivier; LaBauge, Pierre

    2011-12-01

    FDG-PET in ALS most typically demonstrates a primary (and sometimes also supplementary) motor cortex hypometabolism, often associated with more diffuse cortical hypometabolism involving mostly the dorsolateral prefrontal cortex, the medial and lateral premotor cortices, and the bilateral insular cortex involvement. In ALS-FTD, extensive temporal hypometabolism is seen in addition to severe diffuse frontal hypometabolism. This study analyses FDG-PET findings in 6 ALS patients and 4 ALS-FTD patients. In addition to earlier described areas of hypometabolism in ALS, we found also reduced FDG-PET metabolism in the medial frontal cortex, the orbitofrontal cortex, and the anterior temporal lobe in our ALS patients. The anterolateral area was the best preserved part of the frontal lobe in ALS patients. In ALS-FTD, frontal and temporal hypometabolism was severe (and parietal hypometabolism was often also present) with relatively preserved perirolandic metabolism. In ALS, more diffuse frontal and temporal FDG-PET hypometabolism was seen than earlier reported, with the anterolateral area as the best preserved part of the frontal lobe. In ALS-FTD, relatively preserved perirolandic metabolism was seen, associated with severe frontal and temporal hypometabolism.

  17. Metastability in the MgAl2O4-Al2O3 System

    DOE PAGES

    Wilkerson, Kelley R.; Smith, Jeffrey D.; Hemrick, James G.

    2014-07-22

    Aluminum oxide must take a spinel form ( γ-Al2O3) at elevated temperatures in order for extensive solid solution to form between MgAl2O4 and α-Al2O3. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevatedmore » temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.« less

  18. Temperature dependence of the dielectric response of anodized Al-Al2O3-metal capacitors

    NASA Astrophysics Data System (ADS)

    Hickmott, T. W.

    2003-03-01

    The temperature dependence of capacitance, CM, and conductance, GM, of Al-Al2O3-metal capacitors with Cu, Ag, and Au electrodes has been measured between 100 and 340 K at seven frequencies between 10 kHz and 1 MHz. Al2O3 films between 15 and 64 nm thick were formed by anodizing evaporated Al films in borate-glycol or borate-H2O electrolyte. The interface capacitance at the Al2O3-metal interface, CI, which is in series with the capacitance CD due to the Al2O3 dielectric, is determined from plots of 1/CM versus insulator thickness. CI is not fixed for a given metal-insulator interface but depends on the vacuum system used to deposit the metal electrode. CI is nearly temperature independent. When CI is taken into account the dielectric constant of Al2O3 determined from capacitance measurements is ˜8.3 at 295 K. The dielectric constant does not depend on anodizing electrolyte, insulator thickness, metal electrode, deposition conditions for the metal electrode or measurement frequency. By contrast, GM of Al-Al2O3-metal capacitors depends on both the deposition conditions of the metal and on the metal. For Al-Al2O3-Cu capacitors, GM is larger for capacitors with large values of 1/CI that result when Cu is evaporated in an oil-pumped vacuum system. For Al-Al2O3-Ag capacitors, GM does not depend on the Ag deposition conditions.

  19. Vibrational properties of CaAlH5 and α-AlH3 with different AlH6 networks studied by inelastic neutron scattering.

    PubMed

    Sato, Toyoto; Ramirez-Cuesta, A J; Ikeda, Kazutaka; Orimo, Shin-ichi; Yamada, Kazuyoshi

    2011-09-05

    We performed a combined study using inelastic neutron scattering (INS) and first-principles calculations of the vibrational properties of CaAlH(5) and α-AlH(3) with different AlH(6) networks, a zigzag one-dimensional AlH(6) network for CaAlH(5), and a three-dimensional AlH(6) network for α-AlH(3). Both materials showed qualitatively similar INS spectra, in which CaAlH(5)/α-AlH(3) was mainly divided into three regions: (i) the translational modes (318/316 cm(-1)), (ii) the librational modes of the octahedral AlH(6) units (external molecular motion) in the lower frequency range and H-Al-H bond-bending modes (intra molecular motion) at a higher frequency (420-1157/513-1038 cm(-1)), and (iii) the Al-H bond-stretching modes (1238-1750/1486-1942 cm(-1)). In region ii, the appearance of both librational and bond-bending modes was determined by the networked nature of the octahedral AlH(6) units. In addition, the librational modes of AlH(6) on α-AlH(3) exhibit higher frequencies than CaAlH(5) due to the tighter bonding between the octahedral AlH(6) units. With regard to average frequencies for the Al-H, ω(S), bond-stretching modes, and average Al-H bond distances on the aluminum-based hydrides including CaAlH(5) and α-AlH(3), ω(S) showed lower frequencies that correlate with lengthening of the Al-H bond distances.

  20. Relative importance of hydrolyzed Al(III) species (Al(a), Al(b), and Al(c)) during coagulation with polyaluminum chloride: a case study with the typical micro-polluted source waters.

    PubMed

    Yan, Mingquan; Wang, Dongsheng; Qu, Jiuhui; He, Wenjie; Chow, Christopher W K

    2007-12-15

    The relative importance of three different Al species, Al(a) (monomeric species, instantaneous reacted species), Al(b) (medium polymer species, reacted less than 120 min), and Al(c) (colloidal or solid species, no reaction), defined by timed complexation reaction rate measured by using ferron reagent in polyaluminum chloride (PACl) was investigated in terms of DOC (dissolved organic carbon), UV(254), and turbidity removal efficiencies. Micro-polluted, typical North China, source waters were used to conduct the experiments. The results show that DOC removal is correlated well to the content of Al(b). Removal of UV(254) is determined by the content of Al(b) and Al(c), particularly Al(c). Turbidity removal is primarily related to the content of Al(c); however, Al(b) could destabilize particles efficiently, and the flocs formed by Al(b) are not as large as those formed by Al(c), which affected the settling efficiency. Unlike the preformed Al(b), the in situ formed Al(b) could remove turbidity more efficiently since Al(c) is the dominant final species formed during coagulation. Al(a) shows a strong ability to react with some unsatisfied coordinate bonds of organic matter to facilitate particle and DOC removal. The distinct coagulation feature of Al(a), Al(b), and Al(c) can be applied to develop tailor-made PACl (with the correct distribution of Al species) to match the characteristics of raw water for optimized coagulation.

  1. Hören - Psychoakustik - Audiologie

    NASA Astrophysics Data System (ADS)

    Ellermeier, Wolfgang; Hellbrück, Jürgen

    Anatomisch ist das Ohr des Menschen in äußeres Ohr, Mittelohr und Innenohr unterteilt. Zum äußeren Ohr gehören Ohrmuschel (Pinna) und äußerer Gehörgang (Meatus acusticus externus). Die Ohrmuschel besteht - mit Ausnahme des Ohrläppchens - aus Knorpeln. Sie enthält auch Muskelgewebe, das beim Menschen nur noch rudimentär ausgebildet ist und nicht mehr wie bei vielen Tieren durch Bewegung der Ohrmuschel der Schallortung dient.

  2. Protective Al2O3 scale formation on NbAl3-base alloys

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Hebsur, M. G.

    1991-01-01

    The oxidation of NbAl3 with additions of Cr and Y was studied to determine the mechanisms of the beneficial effects of these elements upon oxidation. Cr additions to the binary NbAl3 alloy of up to 6.8 at. percent reduced the scale growth rates and promoted alpha-Al2O3 formation over much longer times relative to binary NbAl3. A major effect of Cr is to form a layer of AlNbCr at the metal/scale interface, which is inherently more oxidation-resistant than the matrix alloy in the long term. Yttrium additions to a Cr-containing alloy improved the scale growth rate and adherence and changed the scale microstructure to mimic that of a typical protective Al2O3 scale.

  3. Magnetic behavior of CoPt-AlN granular structure laminated with AlN layers

    NASA Astrophysics Data System (ADS)

    Yu, Youxing; Shi, Ji; Nakamura, Yoshio

    2011-04-01

    The magnetic behavior of CoPt-AlN granular structure laminated with AlN layers has been studied. Ultrathin multilayer structure, [CoPt0.5 nm/AlN0.5nm]4, is used as the precursor of the magnetic layers, which are separated by 5-nm-thick AlN layers. Upon thermal annealing, the ultrathin multilayer transforms into CoPt-AlN granular structure, and the thick AlN layers remain to be spacers. When the film was annealed at 400 °C, the out-of-plane direction becomes the easy axis of magnetization, although the coercivity remains small. TEM observation has proved that CoPt shows disklike shape at such an annealing temperature. When increasing the annealing temperature to 600 °C and above, the films show "isotropic" magnetic behavior due to the formation of equiaxial CoPt particles in the magnetic layers.

  4. Effects of Al(III) and Nano-Al13 Species on Malate Dehydrogenase Activity

    PubMed Central

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al13 concentration increase. Our study also found that the effects of Al(III) and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules. PMID:22163924

  5. Triclinic Ni[sub 2]Al phase in 63. 1 atomic percent NiAl

    SciTech Connect

    Murthy, A.S.; Goo, E. . Dept. of Materials Science and Engineering)

    1994-01-01

    Transmission electron microscopy (TEM) studies on the 63.1 at pct NiAl specimens aged in the L1[sub 0] phase indicate the presence of localized regions consisting of very high-density twins along with precipitates of Ni[sub 2]Al stoichiometry. In regions representative of the 7R phase, it is observed that the ordered Ni[sub 2]Al phase exists in lattice correspondence with the 7R phase. Based on the electron-diffraction results, the crystal structure of this Ni[sub 2]Al phase is determined to be triclinic, belonging to the space group P[bar 1]. This new Ni[sub 2]Al phase alternatively may be viewed as a periodically microtwinned monoclinic Ni[sub 2]Al phase, existing in coherence with the matrix L1[sub 0] phase that is also periodically microtwinned.

  6. Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS.

    PubMed

    Paré, Bastien; Gros-Louis, François

    2017-03-25

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

  7. Microscopic Properties of Long-Period Ordering in Al-Rich TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Hata, S.; Nakano, T.; Kuwano, N.; Itakura, M.; Matsumura, S.; Umakoshi, Y.

    2008-07-01

    The ordering mechanism of long-period superstructures (LPSs) in Al-rich TiAl alloys has been investigated by high-resolution transmission electron microscopy (HRTEM). The LPSs are classified in terms of arrangements of base clusters with different shapes and compositions formed in Ti-rich (002) layers of L10-TiAl matrix: square Ti4Al, fat rhombus Ti3Al, and lean rhombus Ti2Al type clusters. The HRTEM observations revealed that antiphase boundaries of long-range-ordered LPS domains and short-range-ordered microdomains are constructed by various space-filling arrangements of the base clusters. Such a microscopic property characterized by the base clusters and their arrangements is markedly analogous to that of the {left< {{text{1,1/2,0}}} rightrangle } * special-point ordering alloys such as Ni-Mo.

  8. Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

    PubMed

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  9. TEM studies of oxidized NiAl and Ni3Al cross sections

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Ruhle, M.

    1989-01-01

    Cross sections of oxide scale/(Ni-Al) intermetallics were prepared by a new method and studied using primarily TEM. The cross sections were prepared by encasing an oxidized metal specimen sandwich in a low-melting-temperature zinc alloy. Observations of oxidized zirconium-doped beta-NiAl cross sections revealed crystallographic voids beneath an adherent Al2O3 scale. The oxide-metal interface was incoherent, but a high dislocation density in the metal near the interface suggested that a large tensile stress was induced by the attached oxide scale. A duplex Al2O3-NiAl2O4 scale formed on zirconium-doped and zirconium/boron-doped gamma-prime-Ni3Al alloys. Additional results are presented involving oxidation mechanisms and oxide-metal interface structures.

  10. Improved AlGaN/GaN high electron mobility transistor using AlN interlayers

    NASA Astrophysics Data System (ADS)

    Jiménez, A.; Bougrioua, Z.; Tirado, J. M.; Braña, A. F.; Calleja, E.; Muñoz, E.; Moerman, I.

    2003-06-01

    This work reports on the effects of AlN interlayers embedded into the GaN semi-insulating buffer of AlGaN/GaN high electron mobility transistors, in comparison with standard heterostructures without AlN interlayers. Detailed optical and structural characterization data are presented, along with computer simulation results. The AlN interlayers generate a compressive strain in the GaN topmost layer, which slightly reduces the total polarization field, but most important, it prevents the AlGaN barrier from plastic relaxation. The final result is an enhanced polarization field with respect to standard heterostructures, providing an increased channel carrier density and pinch-off voltage. Electrical characterization confirms the advantages of using AlN interlayers, reaching maximum drain current density and extrinsic transconductance as high as 1.4 A/mm and 266 mS/mm, respectively, for 0.2-μm gate length.

  11. Thermal Properties in the MgAl2O4-Al2O3 System

    SciTech Connect

    Wilkerson, Dr. Kelley R.; Smith, Jeffrey D; Hemrick, James Gordon

    2013-01-01

    Compositional effects on the thermal diffusivity in the MgAl2O4-Al2O3 system were studied. The lowest thermal diffusivity, 0.0258 +/-5% cm/s, was measured between 79.8 and 83.9 wt% Al2O3 quenched from various temperatures between 1500 and 1700C. All of the chemistries in this range extend past the solvus, but still form a singe super-saturated spinel solid solution, regardless of quenching tempeature. A super-saturated metastable solid solution region was observed at 1500, 1600, and 1700C extending to 83.9, 85.2, and 87.1 wt% Al2O3, respectively. Beyond 83.9% Al2O3 a significant increase in thermal diffusivity, 11.7%, was observed and its attributed to precipiation of Al2O3 through spinodal decomposition.

  12. Process Capability Analysis of Vacuum Moulding for Development of Al-Al2O3 MMC

    NASA Astrophysics Data System (ADS)

    Singh, R.

    2013-01-01

    The purpose of the present study is to investigate process capability of vacuum moulding (VM) for development of Al-Al2O3 metal matrix composite (MMC). Starting from the identification of component, prototypes were prepared (with three different input parameters namely: vacuum pressure; component volume and sand grit size to give output in form of dimensional accuracy). Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the Al-Al2O3 MMC prepared. Some important mechanical properties were also compared to verify the suitability of the components. Final components produced are acceptable as per ISO standard UNI EN 20286-I (1995). The results of study suggest that VM process lies in ±4.5 sigma (σ) limit as regard to dimensional accuracy of Al-Al2O3 MMC is concerned. This process ensures rapid production of pre-series technological prototypes and proof of concept at less production cost and time.

  13. Structural inheritance and difference between Ti2AlC, Ti3AlC2 and Ti5Al2C3 under pressure from first principles

    NASA Astrophysics Data System (ADS)

    Gao, Qing-He; Du, An; Yang, Ze-Jin

    2017-01-01

    The structural inheritance and difference between Ti2AlC, Ti3AlC2 and Ti5Al2C3 under pressure from first principles are studied. The results indicate that the lattice parameter a are almost the same within Ti2AlC, Ti3AlC2 and Ti5Al2C3, and the value of c in Ti5Al2C3 is the sum of Ti2AlC and Ti3AlC2 which is revealed by the covalently bonded chain in the electron density difference: Al-Ti-C-Ti-Al for Ti2AlC, Al-Ti2-C-Ti1-C-Ti2-Al for Ti3AlC2 and Al-Ti3-C2-Ti3-Al-Ti2-C1-Ti1-C1-Ti2-Al for Ti5Al2C3. The calculated axial compressibilities, volumetric shrinkage, elastic constant c11, c33/c11 ratio, bulk modulus, shear modulus, and Young’s modulus of Ti5Al2C3 are within the range of the end members (Ti2AlC and Ti3AlC2) in a wide pressure range of 0-100 GPa. Only Ti2AlC is isotropic crystal at about 50 GPa within the Ti-Al-C compounds. All of the Ti 3d density of states curves of the three compounds move from lower energy to higher energy level with pressure increasing. The similarities of respective bond length, bond overlap population (Ti-C, Ti-Al and Ti-Ti), atom Mulliken charges under pressure as well as the electron density difference for the three compounds are discovered. Among the Ti-Al-C ternary compounds, Ti-Ti bond behaves least compressibility, whereas the Ti-Al bond is softer than that of Ti-C bonds, which can also been confirmed by the density of states and electron density difference. Bond overlap populations of Ti-Ti, Ti-C and Ti-Al indicate that the ionicity interaction becomes more and more stronger in the three structures as the pressure increasing. Mulliken charges of Ti1, Ti2, Ti3, C and Al are 0.65, 0.42, 0.39, -0.73, -0.04 at 0 GPa, respectively, which are consistent with the Pauling scale.

  14. The lowest ionization potentials of Al2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.

    1988-01-01

    Potential curves for the lowest two electronic states (X 2 sigma g + and A 2 pi u) of Al2(+) were computed using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2(+) X 2 sigma g +) of the Al2 X 3 pi u ground state is calculated to occur around 6.1 eV, in excellent agreement with the experimental range of 6.0 to 6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2(+) A 2 pi u) occurs near 6.4 eV, also within the experimental range. The adiabatic IP of 5.90 eV is in good agreement with the value of 5.8 to 6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision induced dissociation processes of Al3(+). The computed IP values are somewhat larger than those deduced from branching ratios in cluster fragmentation experiments by Jarrold and co-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3 sigma g -, but the separation between the two lowest states of Al2 is so small that it is likely that both are populated in the experiments, so that this does not provide unambiguous support for the recent theoretical assignment of the ground state as 3 pi u.

  15. Two-Phase (TiAl+TiCrAl) Coating Alloys for Titanium Aluminides

    NASA Technical Reports Server (NTRS)

    Brady, Michael P. (Inventor); Smialek, James L. (Inventor); Brindley, William J. (Inventor)

    1998-01-01

    A coating for protecting titanium aluminide alloys, including the TiAl gamma + Ti3Al (alpha(sub 2)) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C. is disclosed. This protective coating consists essentially of titanium, aluminum. and chromium in the following approximate atomic ratio: Ti(41.5-34.5)Al(49-53)Cr(9.5-12.5)

  16. Influence of RCS on Al-3Mg and Al-3Mg-0.25Sc alloys

    NASA Astrophysics Data System (ADS)

    Bhovi, Prabhakar M.; Venkateswarlu, K.

    2016-02-01

    An influence of repetitive corrugation and straightening (RCS) was studied on Al-3Mg and Al-3Mg-0.25Sc alloys up to eight passes. Each pass consist of a corrugation and followed by straightening. This has resulted in introducing large plastic strain in sample, and thus led to formation of sub-micron grain sizes with high angle grain boundaries. These sub grain formation was eventually resulted in improved mechanical properties. The average grain size of Al-3Mg-0.25Sc alloy after 8 passes yielded to ∼0.6pm. Microhardness, strength properties were evaluated and it suggests that RCS was responsible for high hardness values as compared to the as cast samples. The microhardness values after RCS were 105 HV and 130 HV for Al-3Mg and Al-3Mg-0.25Sc alloys, respectively. Similarly, ∼ 40% improvement in tensile strength from 240 MPa to 370 MPa was observed for Al- 3Mg-0.25Sc alloy after RCS process.Al-3Mg and Al-3Mg-0.25Scalloys exhibited maximum strength of 220 MPa and 370 MPa, respectively. It is concluded that RCS process has a strong influence on Al- 3Mg and Al-3Mg-0.25Sc alloys for obtaining improved mechanical properties and grain refinement. In addition to RCS process and presence of AESc precipitates in Al-3Mg-0.25Sc alloy had a significant role in grain refinement and improved mechanical properties as compared to Al-3Mg alloy.

  17. Stabilization of itinerant (band) magnetism in FeAl by Ga substitution for Al

    NASA Astrophysics Data System (ADS)

    Papaconstantopoulos, D. A.; Mazin, I. I.; Hathaway, K. B.

    2001-06-01

    Band structure calculations of FeGa1-xAlx have been performed, to further investigate the stability of ferromagnetism in FeAl. The Stoner parameter increases by about 20% at the FeGa end. This is also confirmed by our spin-polarized calculations. We conclude that Ga substitution for Al is likely to stabilize the elusive (or illusive) ferromagnetic state in FeAl.

  18. Another Security Improvement over the Lin et al.'s E-voting Scheme

    NASA Astrophysics Data System (ADS)

    Asaar, Maryam Rajabzadeh; Mohajeri, Javad; Salmasizadeh, Mahmoud

    In 2003, Lin et al. have proposed an electronic voting scheme which can be utilized in large-scale elections, and claimed it detects double voting. But in this paper, by presenting an attack, we show that voters can successfully vote more than once without being detected. Hence, we propose a new modified scheme based on the Lin et al.'s scheme with the same efficiency to solve this weakness and analyze its security.

  19. Quantum chemical study of the reactions of Al, AlO and AlOH with H2O2

    NASA Astrophysics Data System (ADS)

    Sharipov, Alexander S.; Starik, Alexander M.

    2016-02-01

    Quantum chemical calculations with the use of hybrid density functional with perturbative second-order correlation and dispersion correction are carried out to study the reactions of Al, AlO and AlOH with the H2O2 molecule. The values of energy barriers are estimated by means of extrapolation to the basis set limit. The energetically favorable reaction pathways have been revealed during the examination of the potential energy surfaces. Complex character of the processes under study has been established. It has been found that the initial stages of the considered processes are barrierless. Appropriate rate constants for principal channels of the reactions under study have been estimated by using capture model and canonical variational theory. The Arrhenius approximations for these channels have been proposed for the temperature range T = 300-4000 K.

  20. Regulation of the Bacillus subtilis alsS, alsD, and alsR genes involved in post-exponential-phase production of acetoin.

    PubMed

    Renna, M C; Najimudin, N; Winik, L R; Zahler, S A

    1993-06-01

    Acetoin is a major extracellular product of Bacillus subtilis grown on glucose and other fermentable carbon sources. The enzymes responsible for the formation of acetoin, acetolactate synthase, and acetolactate decarboxylase are synthesized in detectable amounts only in cells that have reached stationary phase. We have cloned and sequenced the genes encoding these enzymes, alsS and alsD, as well as a gene, alsR, that regulates their expression. alsS and alsD appear to compose a single operon, while alsR is transcribed divergently from the alsSD operon. AlsR shows significant homology to the LysR family of bacterial activator proteins, and when alsR is disrupted the alsSD operon is not expressed. Transcriptional fusions to alsS and alsR revealed that AlsR is required for the transcription of the alsSD operon, which increases during stationary phase. Two mutations that cause increased expression of the alsSD operon have been isolated, cloned, and sequenced. They each change an amino acid in the AlsR protein.

  1. Effect of addition of Si on thermal and electrical properties of Al-Si-Al2O3 composites

    NASA Astrophysics Data System (ADS)

    Cao, R.; Jiang, J. X.; Wu, C.; Jiang, X. S.

    2017-06-01

    Al-5wt.%Si-Al2O3, Al-10wt.%Si-Al2O3, Al-20wt.%Si-Al2O3 composites were fabricated by powder metallurgy and in-situ reactive synthesis technology. The impact of the addition of Si on the thermal and electrical properties was tested and analysed for vary in silicon content in Al-Si-Al2O3 composites. Results show that both thermal expansion coefficient and thermal conductivity decreased as silicon content increased because Si and Al2O3 dispersed in the Al matrix uniformly to suppress the high thermal expansion of Al to a large extent as well as the interfacial thermal resistance which led to the decline in thermal conductivity. Electrical resistivity increased when silicon content was increased because low thermal expansion coefficient particles of Si and Al2O3 severely damaged the continuity of the Al matrix which hindered movement of electron in the matrix.

  2. Small Al clusters. II - Structure and binding in Al(n) (n = 2-6, 13)

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Bauschlicher, Charles W., Jr.; Halicioglu, Timur

    1987-01-01

    The structure and stability of aluminum clusters containing up to six atoms have been studied using correlated wave functions and extended basis sets. The lowest energy structure is planar for Al4 and Al5, but three dimensional for Al6. The icosahedral, hcp, fcc, and two planar structures of Al13 were considered at the SCF level. The lowest energy structure is the icosahedron, but the planar structures are fairly low lying even in this case. A simplified description using two- and three-body interaction potentials is found to agree well with the ab initio structures and binding energies.

  3. Thermal oxidation of the intermetallic phases Al8Mo3 and AlMo3

    NASA Astrophysics Data System (ADS)

    Oster, Michael; Tapp, Joshua; Hagenow, Alexander; Möller, Angela

    2017-07-01

    The thermal oxidation reactions of the intermetallic phases Al8Mo3 and AlMo3 were investigated and analyzed by ex-situ powder-x-ray diffraction (XRD), difference thermal analysis (DTA), thermogravimetry (TGA), and infrared spectroscopy (IR). The initial oxidation reactions in air were found to yield Al2O3 and AlMo3 in the case of Al8Mo3 (Tonset =725 °C), and MoO3 as well as Al8-xMo3 (Tonset =435 °C) for the pure intermetallic phase AlMo3, respectively. Thus, both intermetallic phases are coexisting in an equilibrium within a temperature range of 300 °C under oxidizing conditions. The formation of β-Al2(MoO4)3 followed the second oxidizing process of the respective minority component at elevated temperatures. Decomposition and evaporation of the volatile MoO3 yielded α-Al2O3 as the residue at 1000 °C.

  4. The Dissociation Energies of AlH2 and AlAr

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Partridge, Harry; Bauschlicher, Charles W., Jr.; Visscher, Luuk; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The D(sub 0) values for AlH2 and AlAr are computed using the coupled cluster approach in conjunction with large basis sets. Basis set superposition and spin-orbit effects are accounted for as they are sizeable due to the small binding energy. The computed dissociation energy for AlAr is 101 /cm , which is 83% of the experimental value (122.4/ cm). Our best estimate for the H2 binding energy in AlH2 is 40 +/- 28 /cm.

  5. Synthesis of core-shell AlOOH hollow nanospheres by reacting Al nanoparticles with water

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, A. S.; Glazkova, E. A.; Bakina, O. V.; Lerner, M. I.; Gotman, I.; Gutmanas, E. Y.; Kazantsev, S. O.; Psakhie, S. G.

    2016-05-01

    A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.

  6. Ohmic contacts to Al-rich AlGaN heterostructures

    DOE PAGES

    Douglas, E. A.; Reza, S.; Sanchez, C.; ...

    2017-06-06

    Due to the ultra-wide bandgap of Al-rich AlGaN, up to 5.8 eV for the structures in this study, obtaining low resistance ohmic contacts is inherently difficult to achieve. A comparative study of three different fabrication schemes is presented for obtaining ohmic contacts to an Al-rich AlGaN channel. Schottky-like behavior was observed for several different planar metallization stacks (and anneal temperatures), in addition to a dry-etch recess metallization contact scheme on Al0.85Ga0.15N/Al0.66Ga0.34N. However, a dry etch recess followed by n+-GaN regrowth fabrication process is reported as a means to obtain lower contact resistivity ohmic contacts on a Al0.85Ga0.15N/Al0.66Ga0.34N heterostructure. In conclusion,more » specific contact resistivity of 5×10-3 Ω cm2 was achieved after annealing Ti/Al/Ni/Au metallization.« less

  7. Small Al clusters. II - Structure and binding in Al(n) (n = 2-6, 13)

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Bauschlicher, Charles W., Jr.; Halicioglu, Timur

    1987-01-01

    The structure and stability of aluminum clusters containing up to six atoms have been studied using correlated wave functions and extended basis sets. The lowest energy structure is planar for Al4 and Al5, but three dimensional for Al6. The icosahedral, hcp, fcc, and two planar structures of Al13 were considered at the SCF level. The lowest energy structure is the icosahedron, but the planar structures are fairly low lying even in this case. A simplified description using two- and three-body interaction potentials is found to agree well with the ab initio structures and binding energies.

  8. Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

    PubMed Central

    Liu, Liming; Liu, Fei; Zhu, Meili

    2014-01-01

    Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA) welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated. PMID:28788508

  9. AlN/IDT/AlN/Sapphire SAW Heterostructure for High-Temperature Applications.

    PubMed

    Legrani, Ouarda; Aubert, Thierry; Elmazria, Omar; Bartasyte, Ausrine; Nicolay, Pascal; Talbi, Abdelkrim; Boulet, Pascal; Ghanbaja, Jaafar; Mangin, Denis

    2016-06-01

    Recent studies have evidenced that Pt/AlN/Sapphire surface acoustic wave (SAW) devices are promising for high-temperature high-frequency applications. However, they cannot be used above 700°C in air atmosphere as the Pt interdigital transducers (IDTs) agglomerate and the AlN layer oxidizes in such conditions. In this paper, we explore the possibility to use an AlN protective overlayer to concurrently hinder these phenomena. To do so, AlN/IDT/AlN/Sapphire heterostructures undergo successive annealing steps from 800°C to 1000°C in air atmosphere. The impact of each step on the morphology, microstructure, and phase composition of AlN and Pt films is evaluated using optical microscopy, scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), and secondary ion mass spectroscopy (SIMS). Finally, acoustical performance at room temperature of both protected and unprotected SAW devices are compared, as well as the effects of annealing on these performance. These investigations show that the use of an overlayer is one possible solution to strongly hinder the Pt IDTs agglomeration up to 1000°C. Moreover, AlN/IDT/AlN/Sapphire SAW heterostructures show promising performances in terms of stability up to 800°C. At higher temperatures, the oxidation of AlN is more intense and makes it inappropriate to be used as a protective layer.

  10. HYDROGEN ADSORPTION ON β-TiAl (001) AND Ni/TiAl (001) SURFACES

    NASA Astrophysics Data System (ADS)

    Mubarak, A. A. Karim; Alelaimi, Mahmoud

    2014-04-01

    In this paper, we present first principles calculations of the energetic, electronic and magnetic properties of the variant termination of TiAl (001) and Ni/TiAl (001) surfaces with and without hydrogen atoms. The calculations have been performed within the density functional theory using full-potential linearized augmented plane wave method. The generalized gradient approximation (GGA) is utilized as the exchange-correlation energy. The octahedral site is the stable absorption site of H atom in the β-TiAl system. This absorption reduces the cohesive energy of β-TiAl system due to increase in the lattice constant. The surface energy for both TiAl (001) terminations is calculated. The stable adsorption site of H atoms on the variant termination of TiAl (001) surface is performed. The adsorption energy of hydrogen on Ti is more energetic than that on Al. The adsorption of H atom on both terminations of H/Ni/TiAl (001) is more preferable at the bridge site. The adsorption energies are enhanced on Ni atom due to the contraction between d-Ni bands and TiAl substrate band.

  11. The Dissociation Energies of AlH2 and AlAr

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Partridge, Harry; Bauschlicher, Charles W., Jr.; Visscher, Luuk; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The D(sub 0) values for AlH2 and AlAr are computed using the coupled cluster approach in conjunction with large basis sets. Basis set superposition and spin-orbit effects are accounted for as they are sizeable due to the small binding energy. The computed dissociation energy for AlAr is 101 /cm , which is 83% of the experimental value (122.4/ cm). Our best estimate for the H2 binding energy in AlH2 is 40 +/- 28 /cm.

  12. High temperature deformation of NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Nix, W. D.

    1982-01-01

    The high temperature mechanical properties of the aluminides are reviewed with respect to their potential as high temperature structural materials. It is shown that NiAl and CoAl are substantially stronger than the pure metals Ni and Co at high temperatures and approach the strength of some superalloys, particularly when those superalloys are tested in "weak" directions. The factors that limit and control the high temperature strengths of NiAl and CoAl are examined to provide a basis for the development of intermetallic alloys of this type.

  13. Possible Involvement of Al-Induced Electrical Signals in Al Tolerance in Wheat.

    PubMed Central

    Papernik, L. A.; Kochian, L. V.

    1997-01-01

    The relationship between Al-induced depolarization of root-cell transmembrane electrical potentials (Em) and Al tolerance in wheat (Triticum aestivum L.) was investigated. Al exposure induced depolarizations of Em in the Al-tolerant wheat cultivars Atlas and ET3, but not in the Al-sensitive wheat cultivars Scout and ES3. The depolarizations of Em occured in root cap cells and as far back as 10 mm from the root tip. The depolarization was specific to Al3+; no depolarization was observed when roots were exposed to the rhizotoxic trivalent cation La3+. The Al-induced depolarization occurred in the presence of anion-channel antagonists that blocked the release of malate, indicating that the depolarization is not due to the electrogenic efflux of malate2-. K+-induced depolarizations in the root cap were of the same magnitude as Al-induced depolarizations, but did not trigger malate release, indicating that Al-induced depolarization of root cap cell membrane potentials is probably linked to, but is not sufficient to trigger, malate release. PMID:12223834

  14. Al Studies with INTEGRAL's Spectrometer SPI

    NASA Astrophysics Data System (ADS)

    Diehl, R.; Kretschmer, K.; Lichti, G.; Schönfelder, V.; Strong, A. W.; von Kienlin, A.; Knödlseder, J.; Jean, P.; Lonjou, V.; Weidenspointner, G.; Roques, J.-P.; Vedrenne, G.; Schanne, S.; Mowlavi, N.; Winkler, C.; Wunderer, C.

    2004-10-01

    26 Al radioactivity traces recent nucleosynthesis throughout the Galaxy, and is known to be produced in massive stars and novae. The map from its decay gamma-ray line suggests massive stars to dominate, but high-resolution line spectroscopy is expected to supplement imaging of 26 Al source regions and thus to help decide about the 26 Al injection process and interstellar environment, hence about the specific massive-star subgroup and phase which produces interstellar 26 Al. The INTEGRAL Spectrometer SPI has observed Galactic 26 Al radioactivity in its 1809 keV gamma-ray line during its first inner-Galaxy survey. Instrumental background lines make analysis difficult; yet, a clear signal from the inner Galaxy agrees with expectations. In particular, SPI has constrained the line width to exclude previously- reported line broadenings corresponding to velocities >500 km s-1 . The signal-to-background ratio of percent implies that detector response and background modeling need to be fine-tuned to eventually enable line shape deconvolution in order to extract source location information along the line of sight. Key words: nucleosynthesis; supernovae; novae; massive stars; instruments: gamma-ray telescopes.

  15. Survey and alignment at the ALS

    SciTech Connect

    Krebs, G.F.; Lauritzen, T.; Thur, W.

    1995-11-01

    This paper describes survey and alignment at the Lawrence Berkeley National Laboratory`s Advanced Light Source (ALS) accelerators from 1993 to 1995. The ALS is a 1.0 - 1.9 GeV electron accelerator producing extremely bright synchrotron light in the UV and soft-X-ray wavelengths. At the ALS, electrons are accelerated in a LINAC to 50 MeV, injected into a booster ring for further acceleration and finally injected into the storage ring. This is shown schematically in Figure 1. The storage ring, some 200 m in circumference, has been run with electron currents above 400 mA with lifetimes as high as 24 hours. The ALS is a third generation light source and requires for efficient storage ring operation, magnets aligned to within 150 mm of their ideal position. To accomplish this a network of monuments was established and their positions measured with respect to one another. The data was reduced using GEONET`` and STAR*NET`` software. Using the monuments as reference points, magnet positions were measured and alignment confirmed using the Kem Electronic Coordinate Determination System (ECDS``). A number of other papers dealing with survey and alignment (S&A) at the ALS have been written that may further elucidate some details of the methods and systems described in this paper.

  16. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  17. 78 FR 76054 - Establishment of Class E Airspace; Chatom, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ..., Georgia 30320; telephone (404) 305-6364. ] SUPPLEMENTARY INFORMATION: History On September 4, 2013, the... Above the Surface of the Earth. * * * * * ASO AL E5 Chatom, AL Roy Wilcox Airport, AL (Lat. 31 27'06''...

  18. Different Mechanisms of Four Aluminum (Al)-Resistant Transgenes for Al Toxicity in Arabidopsis1

    PubMed Central

    Ezaki, Bunichi; Katsuhara, Maki; Kawamura, Masako; Matsumoto, Hideaki

    2001-01-01

    We have characterized the mechanism of action of four transgenes (AtBCB [Arabidopsis blue copper-binding protein], parB [tobacco {Nicotiana tabacum} glutathione S-transferase], NtPox [tobacco peroxidase], and NtGDI1 [tobacco GDP dissociation inhibitor]) that independently Al resistance on transgenic Arabidopsis. All four transgenic lines showed lower deposition of callose after Al treatment than the Landsberg erecta ecotype of Arabidopsis, confirming that the four genes function to ameliorate Al toxicity. Influx and efflux experiments of Al ions suggested that the AtBCB gene may suppress Al absorption, whereas expression of the NtGDI1 gene promotes a release of Al in the root tip region of Arabidopsis. The total enzyme activities of glutathione S-transferases or peroxidases in transgenic lines carrying either the parB or NtPox genes were significantly higher than in the Landsberg erecta ecotype of Arabidopsis, and these enzyme activities were maintained at higher levels during Al stress. Furthermore, lipid peroxidation caused by Al stress was repressed in these two transgenic lines, suggesting that overexpression of these two genes diminishes oxidative damage caused by Al stress. Al-treated roots of transgenic plants were also stained by 4′,6-diamino-2-phenylindole to monitor cell death caused by Al toxicity. The result suggested that cell death is repressed in the NtPox line. Analysis of F1 hybrids between the four transgenic lines suggests that more resistant transgenic plants can be constructed by combinations of these four genes. PMID:11706174

  19. Blue electroluminescence from AlN nanowhiskers

    NASA Astrophysics Data System (ADS)

    Vokhmintsev, A. S.; Weinstein, I. A.; Chaikin, D. V.; Fedorov, M. D.; Afonin, Yu. D.

    2015-04-01

    AlN nanowhiskers with an average diameter of 68 nm, for which a chemical analysis showed an Al: N ratio of about 1: 0.8 and a high content of oxygen and carbon impurities, have been synthesized. The electroluminescent properties of the nanostructures have been studied at room temperature in the spectral range of 4.0-1.77 eV (310-700 nm) at varied voltage (75-200 V) and frequency (0.5-10.0 kHz) of the exciting harmonic signal. It is shown that the electroluminescence recorded in the blue spectral range is constituted by bands peaked at E max ≈ 2.53 and 2.75 eV and half-widths ω ≈ 0.39 and 0.30 eV, respectively, which may be associated with electron-optical transitions involving impurity-vacancy centers in the anion and cation sublattices of AlN.

  20. Boron strengthening in FeAl

    SciTech Connect

    Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C.; Carleton, R.L.; George, E.P.

    1998-11-01

    The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.

  1. Unraveling hypothyroidism in AL amyloidosis: Authors' reply.

    PubMed

    Muchtar, Eli; Gertz, Morie

    2017-09-01

    We read with interest the insightful comments by Benvenga and Guarneri (1) on our recently published paper which assessed the high prevalence of hypothyroidism among patients with immunoglobulin light chain (AL) amyloidosis.(2) The paper was the first research paper to address this topic in AL amyloidosis, so we appreciate any insights that can expand the understanding of this complex disease. Amyloidosis is an extremely heterogeneous disorder, and therefore various pathogenic mechanisms may play a role in organ dysfunction. We therefore acknowledge that various causes can lead to the high prevalence (approximately 1 out of 5 patients) of hypothyroidism in Al amyloidosis. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. [Al-Biruni--a universal scientist].

    PubMed

    Kujundzić, E; Masić, I

    1999-01-01

    Al-Biruni's was of Persian descent. He was born in Horesmiya and had studied mathematics, history and medicine. Acquiring knowledge from these sciences, he wrote an outstanding work on chronology of several nations and devoted it to Ziyarit ruler Kabus. He made a chronological overview of calendars from many nations, including Persians, Greeks, Egyptians, Jews, Melkitian and Nestorian Christians, Sabeyaans as well as the old Arabs. Data presented in the work, according to the later authors, were taken from very reliable sources. He was contemporary of Ibn-Sina, and thanks to their friendship, they have discussed very much miscellaneous topics. He belonged to the group of scholars, taken by Gaznevian Soultan Mahmud to a long journey to India. Afterwards Al-Biruni wrote and published detailed work "Description of India"--a work on cultural history of India. Due to excellent abilities of Al-Biruni as a philosopher and scholar, there are still significant and reliable notes about buddhistic philosophy, structure of castes and Brahmans' life style. In this Al-Biruni's masterpiece, there are many comparative analysis of Suffism and certain Indian philosophical methods. Al-Biruni's most important work is "Pharmacopoeia"--"Kitab al-saydala", which brilliantly describes all medicaments. This work has been published in many languages. He also wrote few works on astronomy and astrology. In those works he has explained some astrological events through scientific approach in a such peculiar way that nobody has ever explained before. He was also interested in sciences like geology, mineralology, geography, mathematics, psychology and many others.

  3. A Comment on Eerland et al. (2016).

    PubMed

    Hart, William

    2016-03-01

    People imagine criminal behavior in greater detail and ascribe more blame to criminals when a description of a crime is written using the imperfective verb aspect (Hart & Albarracín, 2011, Experiment 3). An initiative to reproduce these findings conducted by Eerland et al. (2016) yielded a lack of replication. Eerland et al. have suggested that the original effect was likely driven by a Type I error produced by methodological aspects of the experiment, including low sample size. Recent conceptual replications of Hart and Albarracín's effect (Sherrill, Eerland, Zwaan, & Magliano, 2015), however, might imply the effect could be contingent on sample characteristics.

  4. Vibrations on Al surfaces covered by sodium

    NASA Astrophysics Data System (ADS)

    Rusina, G. G.; Eremeev, S. V.; Borisova, S. D.; Sklyadneva, I. Yu.; Chulkov, E. V.

    2006-09-01

    In this paper we present the results of a comparative study of vibrational and structural properties of the ordered (√{3}×√{3})R30∘ and c(2 × 2) phases formed by Na adatoms at room temperature on the Al(1 1 1) and Al(1 0 0) surfaces, respectively. The surface relaxation, surface phonon dispersion, and polarization of vibrational modes are calculated using the embedded-atom method. Our calculated structural parameters are in agreement with experimental and ab initio results. The obtained vibrational frequencies compare fairly well with available experimental data.

  5. Complementary and Alternative Therapies in ALS

    PubMed Central

    Bedlack, Richard S.; Joyce, Nanette; Carter, Gregory T.; Pagononi, Sabrina; Karam, Chafic

    2015-01-01

    Synopsis Given the severity of their illness and lack of effective disease modifying agents, it is not surprising that most patients with ALS consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation and energy healing. This chapter reviews these in detail. We also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy and shared decision making. Finally, we review a program called ALSUntangled which using shared shared decision making to review alternative therapies for ALS. PMID:26515629

  6. Al Qaeda: A Modern Day Lernaean Hydra

    DTIC Science & Technology

    2010-03-01

    St ra te gy R es ea rc h Pr oj ec t AL QAEDA: A MODERN DAY LERNAEAN HYDRA BY MR. MARK A. D’AMATO Department of Army Civilian...strategist, Abu Naji , estimated that 500,000 mujahideen would be necessary “for our long battle and to achieve the results we want.”50 This number...Riedel, The Search for Al Qaeda, Its Leadership, Ideology, and Future, 101. 40 Anthony H . Cordesman, “A Tenuous Case for Strategic Patience in Iraq

  7. Al Qaeda Refining a Failing Strategy

    DTIC Science & Technology

    2008-01-01

    ndupress .ndu.edu issue 51, 4th quarter 2008 / JFQ 117 Al Qaeda Refining a Failing Strategy By M a r t i n J . H a r t Martin J. Hart is an...weak efforts to organize Damage to Pentagon after September 11 attack 1s t C om ba t C am er a S qu ad ro n (C ed ric H . R ud is ill) Report...defeatism.7 Al Qaeda believes such violence can radicalize the Muslim population in a way that simple proselytizing cannot. Naji , for example, calls

  8. The Future of Al Qa’ida

    DTIC Science & Technology

    2011-05-24

    commissions and panels; and private review and oversight bodies. C O R P O R A T I O N For More Information Visit RAND at www.rand.org Explore RAND...affiliated groups and its leadership. A range of senior officials, including Saif al-Adel and Abu Miqad al-Masri, continue to play key roles. Finally, there...20 30 40 50 60 70 2003 2005 2006 2007 2008 2009 2010 Turkey Egypt Jordan Lebanon Indonesia Pakistan Pe rc te nt ag e  of   R es po nd en ts  w it h  Co

  9. Distribution and size of lava shields on the Al Haruj al Aswad and the Al Haruj al Abyad Volcanic Systems, Central Libya

    NASA Astrophysics Data System (ADS)

    Elshaafi, Abdelsalam; Gudmundsson, Agust

    2017-05-01

    The Al Haruj Volcanic Province (AHVP) consists of two distinct volcanic systems. In the north is the system of Al Haruj al Aswad, covering an area of 34,200 km2, while in the south the system of Al Haruj al Abyad, covering an area of 7,850 km2. The systems have produced some 432 monogenetic volcanoes, primarily scoria (cinder) cones, lava shields, and maars. The density distribution of the volcanoes in each system, plotted as eruption points or sites, has a roughly elliptical surface expression, suggesting similar plan-view geometry of the magma sources, here suggested as deep-seated reservoirs. More specifically, the Al Haruj al Aswad magma reservoir has major and minor axes of 210 km and 119 km, respectively, and an area of 19,176 km2, the corresponding figures for the Haruj al Abyad reservoir being 108 km and 74 km, for the axes, and 6209 km2 for the area. We measured 55 lava shields on the AHVP. They are mostly restricted to the northern and southern parts of AHVP and date from late Miocene to (at least) the end of Pleistocene, while some may have been active into Holocene. In fact, although primarily monogenetic, some of the lava shields show evidence of (possibly Holocene) fissure eruptions in the summit parts. The early lava shields tend to be located at the edges of volcanic systems and with greater volumes than later (more central) shields. The average lava shield basal diameter is 4.5 km and height 63 m. There is strong linear correlation between lava shield volume and basal area, the coefficient of determination (R2) being about 0.75. When 22 Holocene Icelandic lava shields are added to the dataset, for comparison, the correlation between volume and basal area becomes R2 = 0.95. Numerical models suggest that the local stress fields favoured rupture and dyke injection at the margins of the source reservoirs during late Miocene - early Pliocene, in agreement with the distribution of the early, large-volume shields.

  10. Electronic circuits having NiAl and Ni.sub.3 Al substrates

    DOEpatents

    Deevi, Seetharama C.; Sikka, Vinod K.

    1999-01-01

    An electronic circuit component having improved mechanical properties and thermal conductivity comprises NiAl and/or Ni.sub.3 Al, upon which an alumina layer is formed prior to applying the conductive elements. Additional layers of copper-aluminum alloy or copper further improve mechanical strength and thermal conductivity.

  11. An Alternative Perspective on von Winterfeldt et al.'s (1997) Test of Consequence Monotonicity

    ERIC Educational Resources Information Center

    Ho, Moon-Ho R.; Regenwetter, Michel; Niederee, Reinhard; Heyer, Dieter

    2005-01-01

    D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (see record 1997-03378-008) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a…

  12. Transport mechanisms of leakage current in Al2O3/InAlAs MOS capacitors

    NASA Astrophysics Data System (ADS)

    Jin, Chengji; Lu, Hongliang; Zhang, Yimen; Zhang, Yuming; Guan, He; Wu, Lifan; Lu, Bin; Liu, Chen

    2016-09-01

    An Al2O3 layer is inserted between the InAlAs layer and the metal gate in InAs/AlSb HEMTs to suppress the leakage current. The transport mechanisms of leakage current in Al2O3/InAlAs metal-oxide-semiconductor (MOS) capacitors at both positive and negative biases at different temperatures ranging from 10 °C to 70 °C are investigated. For positive bias, the leakage current is dominated by Schottky emission. Based on the fitted straight lines, the relative dielectric constant of Al2O3 and the barrier height between Al2O3 and InAlAs are extracted. However, for negative bias, the leakage current is dominated by Frenkel-Poole (F-P) emission and the depth of the trap energy level from the conduction band (ϕt) is extracted. Furthermore, authors explain the reason why the dominating mechanisms at positive and negative biases are different.

  13. Directional Solidification and Mechanical Properties of NiAl-NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Chen, X. F.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1995-01-01

    Directional solidification of eutectic alloys is a promising technique for producing in-situ composite materials exhibiting a balance of properties. Consequently, the microstructure, creep strength and fracture toughness of directionally solidified NiAl-NiAlTa alloys were investigated. Directional solidification was performed by containerless processing techniques to minimize alloy contamination. The eutectic composition was found to be NiAl-15.5 at% Ta and well-aligned microstructures were produced at this composition. A near-eutectic alloy of NiAl-14.5Ta was also investigated. Directional solidification of the near-eutectic composition resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The off-eutectic alloy exhibited promising compressive creep strengths compared to other NiAl-based intermetallics, while preliminary testing indicated that the eutectic alloy was competitive with Ni-base single crystal superalloys. The room temperature toughness of these two-phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa.

  14. Draft Genome Sequences of the Aerobic Strains Lactobacillus gasseri AL3 and AL5

    PubMed Central

    Maresca, Diamante; De Filippis, Francesca; de Vos, Willem M.

    2017-01-01

    ABSTRACT Adaptation to the aerobic environment has been investigated in heterofermentative lactobacilli, while data on how homofermentative lactobacilli adapt to oxygen are limited. We report here the draft genome sequences of the aerobic strains Lactobacillus gasseri AL3 and AL5 that allow an in-depth investigation of the genes involved in oxidative metabolism and the stress response. PMID:28473372

  15. Heterogeneity of Mg Isotopes and Variable ^26Al/^27Al Ratio in FUN CAIs

    NASA Astrophysics Data System (ADS)

    Park, C.; Nagashima, K.; Hutcheon, I. D.; Wasserburg, G. J.; Papanastassiou, D. A.; Davis, A. M.; Huss, G. R.; Krot, A. N.

    2013-09-01

    We report high-precision Mg-isotope data of individual minerals from the Axtell 2271, BG82DH8, EK1-4-1, C1, TE, and CG14 FUN CAIs, which shows variations in both Mg-isotope ratio and ^26Al/^27Al ratio.

  16. Fabrication and Characterization of AL-AL4C3 Nanocomposite by Mechanical Alloying

    NASA Astrophysics Data System (ADS)

    Mohammad Sharifi, E.; Enayati, M. H.; Karimzadeh, F.

    Aluminum carbide (Al4C3) seems to be an ideal reinforcement for producing aluminum matrix composites. Al4C3 has high hardness and shear strength as well as a high melting point. The dispersion of Al4C3 particles in the matrix produces a pinning effect that reduces aluminum grain growth, which improves the mechanical properties. In this study, aluminum powders were mixed with 4.5 wt.% graphite and mechanically alloyed using a high-energy ball mill in order to produce Al-Al4C3 nanocomposite. The structural evaluation of powder particles after different milling times was studied by X-ray diffractometry, scanning electron microscopy and microhardness measurements. The aluminum crystallite size estimated with broadening of XRD peaks by Williamson-Hall formula. XRD results suggested that the grain size of aluminum decreased to nanometer range (30 nm) during ball milling. No Al4C3 formed during the mechanical alloying process. Milled powders were then annealed at 300-600 °C for 1 h under argon atmosphere. Annealing at temperatures higher than 300 °C led to formation of Al4C3 phase which increased as annealing temperature increased. Aluminum grain size remained in nanometer range after annealing process. The microhardness of powder particles increased after annealing. Both effects are due to the formation of nanosized Al4C3 particles.

  17. An Alternative Perspective on von Winterfeldt et al.'s (1997) Test of Consequence Monotonicity

    ERIC Educational Resources Information Center

    Ho, Moon-Ho R.; Regenwetter, Michel; Niederee, Reinhard; Heyer, Dieter

    2005-01-01

    D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (see record 1997-03378-008) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a…

  18. The Genyornis Egg: Response to Miller et al.'s commentary on Grellet-Tinner et al., 2016

    NASA Astrophysics Data System (ADS)

    Grellet-Tinner, Gerald; Spooner, Nigel A.; Handley, Warren D.; Worthy, Trevor H.

    2017-04-01

    Williams (1981) and Williams and Rich (1991) attributed Australian Quaternary fossil eggshell that differed from that of emu Dromaius novaehollandiae to the extinct bird Genyornis newtoni without any osteological or embryonic support. Such association by proximity or abundance mirrors the case of the mistaken association of oviraptor eggs to Protoceratops in the 1920's by Andrews (Grellet-Tinner and Makovicky, 2006). No other candidate species was considered, and this attribution has been unchallenged and followed by everyone thereafter. Much research has been done on this Australian eggshell, with one result being that the extinction of the parent of this eggshell is the most well documented for a taxon in Australia (e.g., Miller et al., 1999, 2005). Grellet-Tinner et al. (2016) raised several problems with the identity of the eggshell Williams (1981) attributed to Genyornis newtoni and suggested that extinct megapodes of the genus Progura were the more likely layer of this eggshell type, therein referred to as ;putative Genyornis oological material; (PGOM). Miller et al. (2017) challenged our hypothesis stating that ;Based on the dimensions of the reconstructed Spooner Egg,Grellet-Tinner et al. (2016)argue that PGOM is too small for a bird with the body mass estimated for Genyornis (168-275 kg) … …[and] …. None of the additional PGOM observations reported byGrellet-Tinner et al. (2016)are inconsistent with a Genyornis parent;. Here we take the opportunity to respond to their critique, the basis of which resolves into a few points, which we address in turn.

  19. Electronic Spectroscopy of AlArn Clusters: Evidence for Surface Binding of Al Atoms

    NASA Astrophysics Data System (ADS)

    Okumura, Mitchio; Spotts, James M.; Wong, Chi-Kin

    1997-04-01

    Solvent-induced-frequency shifts and splittings of the 3p arrow 3d transition of Al atoms in Al(Ar)n clusters were studied to investigate the site occupied by the Al atom in these clusters. The electronic spectra were recorded near 300 nm for several sizes in the range n = 1 to 60 by resonant two-photon photoionization spectroscopy. The observed bands differ significantly from UV absorption spectra of Al atoms in Ar matrices, and the variations in splittings and shifts as a function of cluster size do not converge on the matrix limit. These results are interpreted with a model in which the Al atom is bound to the surface of an Arn cluster rather than solvated within the cluster interior.

  20. Al/sub 2/O/sub 3/ adherence on CoCrAl alloys

    SciTech Connect

    Kingsley, L.M.

    1980-04-01

    Adherence of protective oxides on NiCrAl and CoCrAl superalloys has been promoted by a dispersion of a highly oxygen reactive element or its oxide being produced within the protection system. Two aspects of this subject are investigated here: the use of Al/sub 2/O/sub 3/ as both the dispersion and protective oxide; and the production of an HfO/sub 2/ dispersion while simultaneously aluminizing the alloy. It was found that an Al/sub 2/O/sub 3/ dispersion will act to promote the adherence of an external scale of Al/sub 2/O/sub 3/ to a degree comparable to previously tested dispersions and an HfO/sub 2/ dispersion comparable to that produced by a Rhines pack treatment is produced during aluminization.

  1. 1400 and 1500 K Compressive Creep Properties of an NiAl/AlN Composite

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Arzt, Eduard; Luton, Michael J.

    1992-01-01

    Compressive creep properties of an NiAl/AlN(p) composite produced by a reaction milling process were investigated at 1400 and 1500 K and at slow strain rates, to investigate the relative strength of this composite at high temperatures, and to determine if the consolidation technique affects the 1400 K creep properties. Results indicate that the stress exponent of the NiAl/AlN(p) composite was similar to that for unreinforced NiAl. However, the activation energy for the composite was found to be more than twice that measured in the unreinforced matrix. Oxidation did not affect the composite at 1400 K, but a significant attack was observed in a sample subjected to fast deformation at 1500 K.

  2. Temperature dependence of the activity of Al in dilute Ni(Al) solid solutions

    SciTech Connect

    Jiang Yong; Smith, J. R.; Evans, A. G.

    2006-12-01

    Activities of dilute Al solid solutions in Ni are determined from a first-principles approach. Both thermal lattice vibration and electronic contributions to free energies are considered and compared. Vibrational contributions tend to dominate the temperature dependencies of the free energies, though electron thermal effects are significant. Calculations show opposing temperature trends for the formation enthalpies and entropies, leading to a partial cancellation of their role in the overall energetics. Nevertheless, their remaining temperature effects are strong. Over the temperature range, 400 KAl activity coefficient varies by 15 orders of magnitude, due to the relative strength of Al-Ni and Al-Al bonds. The Ni activity coefficient only varies less than 4% over the same range. Calculational results compare well with available experimental data. The thermodynamic principles elucidated from the calculations are used to provide a fundamental interpretation.

  3. Fundamental Influence of C on Adhesion of the Al2O3/Al Interface

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Gang; Smith, John R.; Evans, Anthony

    2002-12-01

    Our first-principles computations indicate that the clean Al2O3/Al interface is relatively weak—weaker than bulk Al. Fracture experiments reveal that the interface is relatively strong with observed failure in bulk Al, however. This paradox is resolved via doping effects of the common impurity C. We have found that only 1/3 of a monolayer of carbon segregated to the interface can increase the work of separation by a factor of 3. The resulting strong interface is consistent with fracture experiments. It arises due to void formation in the interface, which provides low-strain sites for the carbon to segregate to. The degree of void formation is consistent with the relatively high heat of oxide formation of Al.

  4. Grain refinement of 7075Al alloy microstructures by inoculation with Al-Ti-B master alloy

    NASA Astrophysics Data System (ADS)

    Hotea, V.; Juhasz, J.; Cadar, F.

    2017-05-01

    This paper aims to bring some clarification on grain refinement and modification of high strength alloys used in aerospace technique. In this work it was taken into account 7075 Al alloy, and the melt treatment was carried out by placing in the form of master alloy wire ternary AlTiB the casting trough at 730°C. The morphology of the resulting microstructures was characterized by optical microscopy. Micrographs unfinished and finished with pre-alloy containing ternary Al5Ti1B evidence fine crystals, crystal containing no columnar structure and highlights the size of the dendrites, and intermetallic phases occurring at grain boundaries in Al-Zn-Mg-Cu alloy. It has been found that these intermetallic compounds are MgZn2 type. AlTiB master alloys finishing ensures a fine eutectic structure, which determines the properties of hardware and improving the mechanical properties of aluminum alloys used in aeronautical engineering.

  5. 1300 K compressive properties of a reaction milled NiAl-AlN composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Arzt, Eduard; Luton, Michael J.

    1990-01-01

    When B2 crystal-structure nickel aluminide is subjected to high-intensity mechanical ball milling in a liquid nitrogen bath, or 'cryomilling', an NiAl composite is obtained which contains about 10 vol pct AlN particles. This composition arises from the incorporation of N during cryomilling; during subsequent thermomechanical processing, the N reacts with Al. While compressive testing of extruded or isostatically pressed specimens at 1300 K indicated that strength at relatively fast strain rates is slightly dependent on consolidation method, slower strain rates indicate no clear dependency on densification technique: four different consolidation methods were found to yield similar creep strengths. The creep properties of NiAl-AlN are similar to those of the single-crystal Ni-base superalloy NASAIR 100.

  6. An impedance study of complex Al/Cu-Al2O3 electrode

    NASA Astrophysics Data System (ADS)

    Denisova, J.; Katkevics, J.; Erts, D.; Viksna, A.

    2011-06-01

    Electrochemical impedance spectroscopy (EIS) was used to investigate different Cu deposition regimes on Al surface obtained by internal electrolysis and to characterize properties of fabricated electrodes. EIS experimental data confirmed that Cu deposition by internal electrolysis is realized and the complex electrode system is obtained. The main difficulty in preparation of Al/Cu electrodes is to prevent aluminium oxidation before and during electrochemical deposition of Cu particles. In this work NaCl, CH3COONa, K2SO4, mono- and diammonium citrate electrolytes were examined to determine their suitability for impedance measurements. Al/Cu-Al2O3 electrode composition was approved by equivalent circuit analysis, optical and scanning electron microscope methods. The most optimal Cu deposition mode using internal electrolysis was determined. The obtained results are promising for future electrochemical fabrication of nanostructures directly on Al surfaces by internal electrolysis.

  7. CVD Fiber Coatings for Al2O3/NiAl Composites

    NASA Technical Reports Server (NTRS)

    Boss, Daniel E.

    1995-01-01

    While sapphire-fiber-reinforced nickel aluminide (Al2O3/NiAl) composites are an attractive candidate for high-temperature structures, the significant difference in the coefficient of thermal expansion between the NiAl matrix and the sapphire fiber creates substantial residual stresses in the composite. This study seeks to produce two fiber-coating systems with the potential to reduce the residual stresses in the sapphire/NiAl composite system. Chemical vapor deposition (CVD) was used to produce both the compensating and compliant-fiber coatings for use in sapphire/NiAl composites. A special reactor was designed and built to produce the FGM and to handle the toxic nickel precursors. This process was successfully used to produce 500-foot lengths of fiber with coating thicknesses of approximately 3 microns, 5 microns, and 10 microns.

  8. Bonding characters of Al-containing bulk metallic glasses studied by 27Al NMR.

    PubMed

    Xi, X K; Sandor, M T; Wang, H J; Wang, J Q; Wang, W H; Wu, Y

    2011-03-23

    We report very small (27)Al metallic shifts in a series of Cu-Zr-Al bulk metallic glasses. This observation and the Korringa type of spin-lattice relaxation behavior suggest that s-character wavefunctions weakly participate in bonding and opens the possibility of enhanced covalency (pd hybridization) with increasing Al concentration, in good agreement with elastic constants and hardness measurements. Moreover, ab initio calculations show that this bonding character originates from the strong Al 3p band and Zr 4d band hybridization since their atomic energy levels are closer to each other while the Al 3s band is localized far below the Fermi level. This study might provide a chemical view for understanding flow and fracture mechanisms of these bulk glass-forming alloys.

  9. Wear characteristics of Al-AlN composites produced in-situ by nitrogenation

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Jena, S. K.; Patnaik, S. C.; Swain, P. K.; Majhi, J.

    2015-02-01

    In the present scenario most of the parts used in automobile and aerospace industries are made of composites. Aluminium metal has a very high strength to weight ratio. Al-AlN metal matrix composites have excellent mechanical properties like good wear resistance, high hardness and high strength to weight ratio which are obtained from low density of aluminium and high hardness and wear resistance of AlN. Therefore, use of Al-AlN MMC leads to advantages in automobile industries as it reduces fuel consumption and gives better structural strength. The composites can be produced ex-situ by introducing AlN as reinforcement into the metal matrix and in- situ by nitrogenation process. In the present process Al-AlN composites were fabricated by treating molten aluminium with a mixture of CaO and NH4Cl and held at temperature range at 750-930°C and then cast into a metal mould. Addition of CaO to NH4Cl is found to have a more pronounced effect as a nitrogenation agent in comparison with NH4Cl in the molten aluminium in the temperature range of 700- 1000°C. Castings of aluminium and Al-AlN composites were prepared by mixing different ratios of aluminium and NH4Cl, at different casting temperatures and holding time. Wear resistance and hardness of the samples were determined, and microstructure studies were carried out. The composite formed using higher amount of NH4Cl had higher hardness and wear resistance.

  10. Formation of gamma(sup prime)-Ni3Al via the Peritectoid Reaction: gamma + beta (+ Al2O3)=gamma(sup prime)(+ Al2O3)

    NASA Technical Reports Server (NTRS)

    Copeland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8-32 at.%Al and temperature range T=1400-1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma(sup prime)-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3)=gamma + Beta(+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%al (at an unknown oxygen content). The {gamma + Beta (+Al2O3} phase field is stable over the temperature range 1633-1640 K, and gamma(sup prime)-Ni3Al forms via the peritectoid, gamma + Beta (+ Al2O3)=gamma(sup prime) (+ Al2O3), at 1633 +/- 1 K. This behavior is consistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(sup prime)-Ni2Al phase field.

  11. Formation of gamma'-Ni3Al via the Peritectoid Reaction: gamma plus beta (+Al2O3) equals gamma'(+Al2O3)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma'-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3) = gamma + beta (+ Al2O3), at 1640 plus or minus 1 K and a liquid composition of 24.8 plus or minus 0.2 at.%Al (at an unknown oxygen content). The {gamma + beta + Al2O3} phase field is stable over the temperature range 1633 - 1640 K, and gamma'-Ni3Al forms via the peritectiod, gamma + beta (+ Al2O3) = gamma'(+ Al2O3), at 1633 plus or minus 1 K. This behavior is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma'-Ni3Al phase field.

  12. Reduced graphene oxide as a protection layer for Al

    NASA Astrophysics Data System (ADS)

    Jang, Haneul; Kim, Jae-Hun; Kang, Heon; Bae, Donghyun; Chang, Hyejung; Choi, Hyunjoo

    2017-06-01

    This study proposes a facile solution process to generate a reduced graphene oxide (rGO) protection layer on Al, in which polyvinyl alcohol (PVA) is used to enhance interfacial bonding between Al and rGO. A multi-level analysis indicated that PVA-aided coating induced numerous conjugations between Al and rGO by producing a large number of hydroxyl groups on the Al surface. The Al plate directly coated by rGO showed good corrosion resistance compared with the pristine Al, implying that rGO may act as an effective corrosion barrier for Al. Moreover, the Al coated by the PVA-aided process exhibited higher corrosion resistance than the directly coated Al as well as the pristine Al due to the enhanced adhesion between Al and rGO.

  13. The modulation structure induced changes in mechanical properties of TiAlN/Al2O3 multilayers

    NASA Astrophysics Data System (ADS)

    Yan, J. Y.; Li, D. J.; Dong, L.; Gao, C. K.; Wang, N.; Deng, X. Y.; Gu, H. Q.; Wan, R. X.; Sun, X.

    2013-07-01

    TiAlN/Al2O3 multilayers which had different separate layer thickness of TiAlN or Al2O3 were synthesized by sputtering Ti3Al and Al2O3 targets with N2 and Ar gases. The influence of modulation periods and modulation ratios on structure and properties of TiAlN/Al2O3 multilayers was investigated using scanning electron microscopy, X-ray diffraction, X-ray Photoelectron Spectroscopy, surface profiler, and nanoindenter. Compared to TiAlN layer with only (2 0 0) preferred orientation, TiAlN/Al2O3 multilayers were crystallized with orientations in the TiAlN (1 1 1), TiAlN (2 2 2) and AlN (1 0 0). Besides, weak Al2O3 (0 2 2) orientation is observed, when modulation period is 8.9 nm. The maximum hardness about 36.6 GPa was obtained at modulation period of 10.4 nm and modulation ratio of 10:1. The hardness and the toughness of TiAlN/Al2O3 multilayers increase as individual TiAlN layer thickness increases.

  14. 76 FR 35938 - The Designation of Othman al-Ghamdi Also Known as Al Umairah al-Ghamdi, Also Known as Uthman al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... [Federal Register Volume 76, Number 118 (Monday, June 20, 2011)] [Notices] [Page 35938] [FR Doc No: 2011-15290] DEPARTMENT OF STATE [Public Notice 7505] The Designation of Othman al-Ghamdi Also Known as... the Federal Register. Dated: May 11, 2011. Hillary Rodham Clinton, Secretary of State. [FR Doc....

  15. Hughes et al.: Science or Promotion?

    ERIC Educational Resources Information Center

    Loman, L. Anthony; Siegel, Gary L.

    2013-01-01

    The Hughes et al. paper is critiqued generally and in specific areas. The weak nature of the authors' empirical work is discussed along with their enigmatic writing and vague and incorrect use of references, and their simultaneous use of sweeping statements of opinion and narrow analytical focus. This review examines the authors' errors…

  16. Al-Qaida: Terrorist Selection and Recruitment

    DTIC Science & Technology

    2006-01-01

    like them, not alien outsiders. 9. Surrounding potential recruits with peers who are already established recruits. 10. E. Goffman , Behavior in Public...Cultic Studies Journal 1:2 (1984): 167–177. 88 SECTION 1 Al-Qaida and Global Jihad Goffman , E., Behavior in Public Places: Notes on the Social

  17. 75 FR 1420 - Alabama Disaster # AL-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00025 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  18. 78 FR 4967 - Alabama Disaster #AL-00046

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00046 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of ALABAMA dated...

  19. 75 FR 474 - Alabama Disaster #AL-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... [Federal Register Volume 75, Number 2 (Tuesday, January 5, 2010)] [Notices] [Pages 474-475] [FR Doc No: E9-31259] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 11988 and 11989] Alabama Disaster AL-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice...

  20. 78 FR 26100 - Alabama Disaster #AL-00050

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00050 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  1. 77 FR 7227 - Alabama Disaster #AL-00040

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00040 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Alabama...

  2. 75 FR 26814 - Alabama Disaster #AL-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... [Federal Register Volume 75, Number 91 (Wednesday, May 12, 2010)] [Notices] [Pages 26814-26815] [FR Doc No: 2010-11201] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12157 and 12158] Alabama Disaster AL-00031 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice...

  3. 78 FR 22361 - Alabama Disaster #AL-00049

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Alabama Disaster AL-00049 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Alabama dated...

  4. 75 FR 26813 - Alabama Disaster #AL-00029

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... [Federal Register Volume 75, Number 91 (Wednesday, May 12, 2010)] [Notices] [Pages 26813-26814] [FR Doc No: 2010-11199] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12155 and 12156] Alabama Disaster AL-00029 AGENCY: Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of...

  5. Quantum Criticality in YFe2Al10

    NASA Astrophysics Data System (ADS)

    Gannon, William; Wu, Liusuo; Zaliznyak, Igor; Qiu, Yiming; Rodriguez-Rivera, Jose; Aronson, Meigan

    Quantum criticality has been studied in many systems, but there are few systems where observed scaling can be unified with a critical free energy F, or where the critical exponents form the basis for QC universality classes. We have identified a new layered material YFe2Al10 that shows remarkably strong QC behavior, where the scaling properties of the magnetic susceptibility and specific heat are consistent with the same F. Recent neutron scattering results paint a remarkable picture of the QC fluctuations in YFe2Al10. In contrast to classical transitions, where fluctuations are relatively long ranged and inelastic scattering is observed at a magnetic zone center, in YFe2Al10 the scattering is independent of wave vector in the critical plane, indicating that the fluctuations are spatially localized, while out of plane scattering indicates that the interplaner interactions are restricted to nearest neighbors. The dynamical susceptibility χ'' ~=E-2 , and is wholly temperature independent, indicating that E/T scaling is present, the signature of QC fluctuations. These results hint that the the criticality in YFe2Al10 is local, which until now has only been found in a few f-electron based compounds.

  6. Correction to Rothermund et al. (2005)

    ERIC Educational Resources Information Center

    Rothermund, Klaus; Wentura, Dirk; De Houwer, Jan

    2005-01-01

    This article reports an error in the article "Retrieval of Incidental Stimulus-Response Associations as a Source of Negative Priming" by Rothermund et al. ("Journal of Experimental Psychology: Learning, Memory, and Cognition," Vol 31(3) May 2005, 482-495). Table 1 (p. 484) was incorrectly typeset. The correct layout is provided. (The following…

  7. Cryptanalysis on Cheng et al. protocol

    NASA Astrophysics Data System (ADS)

    Thakur, Tejeshwari

    2016-06-01

    Deployment of new node in any wireless sensor network is a sensitive task. This is the reason why, an Access Control Protocol is required in WSN. In this paper, we demonstrate that Access Control Protocol proposed by Cheng et al.[1] for Wireless Sensor Network is insecure. The reason is that this protocol fails to resist the active attack.

  8. Al-Ghazali on Moral Education

    ERIC Educational Resources Information Center

    Alavi, Hamid Reza

    2007-01-01

    Al-Ghazali (1058-1111 CE) is probably the most influential scholar, philosopher, theologian, legal expert, religious reformer and mystic in the history of Islam. Although he wrote extensively about education, and particularly about moral education, this writing is scattered through a number of different works and has received less scholarly…

  9. SPI measurements of Galactic 26Al

    NASA Astrophysics Data System (ADS)

    Diehl, R.; Knödlseder, J.; Lichti, G. G.; Kretschmer, K.; Schanne, S.; Schönfelder, V.; Strong, A. W.; von Kienlin, A.; Weidenspointner, G.; Winkler, C.; Wunderer, C.

    2003-11-01

    The precision measurement of the 1809 keV gamma-ray line from Galactic 26Al is one of the goals of the SPI spectrometer on INTEGRAL with its Ge detector camera. We aim for determination of the detailed shape of this gamma-ray line, and its variation for different source regions along the plane of the Galaxy. Data from the first part of the core program observations of the first mission year have been inspected. A clear detection of the 26Al line at =~ 5-7 sigma significance demonstrates that SPI will deepen 26Al studies. The line intensity is consistent with expectations from previous experiments, and the line appears narrower than the 5.4 keV FWHM reported by GRIS, more consistent with RHESSI's recent value. Only preliminary statements can be made at this time, however, due to the multi-component background underlying the signal at =~ 40 times higher intensity than the signal from Galactic 26Al.

  10. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  11. Hughes et al.: Science or Promotion?

    ERIC Educational Resources Information Center

    Loman, L. Anthony; Siegel, Gary L.

    2013-01-01

    The Hughes et al. paper is critiqued generally and in specific areas. The weak nature of the authors' empirical work is discussed along with their enigmatic writing and vague and incorrect use of references, and their simultaneous use of sweeping statements of opinion and narrow analytical focus. This review examines the authors' errors…

  12. Al Qaeda: Profile and Threat Assessment

    DTIC Science & Technology

    2005-08-17

    Egypt. Like Abd al-Rahman, Zawahiri had been imprisoned but ultimately acquitted for the October 1981 assassination of Egyptian President Anwar Sadat...killed in Kabul, Afghanistan by U.S. Predator; September 11 planner Khalid Shaikh Mohammed, arrested by Pakistani agents near Rawalpindi; key

  13. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  14. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  15. Electron impact exctation of Al X

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti; Keenan, Francis

    2013-05-01

    Emission lines of Al ions, including Al X, are important for the modeling and diagnostics of lasing, fusion and astrophysical plasmas, for which atomic data are required for a variety of parameters, such as energy levels, radiative rates (A- values), and excitation rates or equivalently the effective collision strengths (Υ), which are obtained from the electron impact collision strengths (Ω). Experimentally, energy levels are available for Al X on the NIST website, but there is paucity for accurate collisional atomic data. Therefore, here we report a complete set of results (namely energy levels, radiative rates, and effective collision strengths) for all transitions among the lowest 98 levels of Al X. These levels belong to the (1s2) 2s2, 2s2p, 2p2, 2s3 l, 2p3 l, 2s4 l, and 2p4 l configurations. Finally, we also report the A- values for four types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2), because these are also required for plasma modeling. For our calculations of wavefunctions, we have adopted the fully relativistic GRASP code, and for the calculations of Ω, the Dirac atomic R-matrix code (DARC) of PH Norrington and IP Grant. Additionally, parallel ca

  16. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  17. U-ALS: A Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Piovesan, Sandra Dutra; Passerino, Liliana Maria; Medina, Roseclea Duarte

    2012-01-01

    The diffusion of the use of the learning virtual environments presents a great potential for the development of an application which meet the necessities in the education area. In view of the importance of a more dynamic application and that can adapt itself continuously to the students' necessities, the "U-ALS" (Ubiquitous Adapted Learning…

  18. Hopkins in the A/L

    NASA Image and Video Library

    2013-12-18

    View of Mike Hopkins, Expedition 38 Flight Engineer (FE), during remove and replace (R&R) of Hard Upper Torso (HUT) of Extravehicular Mobility Unit (EMU), in the airlock (A/L) during preparation for EVA-24. Photo was taken during Expedition 38. Image was released by astronaut on Twitter.

  19. Al/Cl2 molten salt battery

    NASA Technical Reports Server (NTRS)

    Giner, J.

    1972-01-01

    Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

  20. Bierman {ital et al.}Reply:

    SciTech Connect

    Bierman, J.D.; Chan, P.; Liang, J.F.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R.

    1997-05-01

    reply to the Comment by C.H.Dasso et al., Phys. Rev. Lett. 78,XXX(1997). A Reply to the Comment by C.H. Dasso and J. Fern{acute a}ndez-Niello. {copyright} {ital 1997} {ital The American Physical Society}

  1. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids were observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. The voids resulted from an excess number of oxygen vacancies near the oxidemetal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidation of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al, Cr)2O3 and Ni(Al, Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationship between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  2. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids have been observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. It was postulated that the voids resulted from an excess number of oxygen vacancies near the oxide-metal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidations of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al,Cr)2O3 and Ni(Al,Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationships between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  3. Effect of speciation transformation on the coagulation behavior of Al(13) and Al(13) aggregates.

    PubMed

    Wu, Xiaohong; Ye, Changqing; Wang, Dongsheng; Ge, Xiaopeng; Tang, Hongxiao

    2009-01-01

    Flocculation of kaolin suspension with aluminium fractal polycations was investigated as a function of aluminium concentration and pH. Aluminium flocculants included Al(13) and Al(13) aggregates with OH/Al ratio of 2.6 and 2.8, respectively. The flocculation kinetics and floc size distribution were monitored by light scattering. The characterization of flocculants showed that the tridecatmer Al(13) and bridged [Al(13)](n) with out-sphere structure were the dominant species for all flocculants in a wide pH range. The coagulation results indicated that the pre and in situ-formed [Al(13)](n) play a key role in removing particles. With the increasing concentration of [Al(13)](n), coagulation mechanisms were transformed from charge-neutralization, electro-patch coagulation to bridge-aggregation. Moreover, sweep-flocculation was involved at higher dosage besides other three mechanisms when amorphous aluminium oxides formed. Hence, chemical interaction between particles and flocculants evolved from surface adsorption to surface precipitation for aluminium polycations by virtue of species transformation.

  4. A novel Al matrix composite reinforced by nano-AlNp network

    PubMed Central

    Ma, X.; Zhao, Y. F.; Tian, W. J.; Qian, Z.; Chen, H. W.; Wu, Y. Y.; Liu, X. F.

    2016-01-01

    In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The in-situ synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials. PMID:27721417

  5. AlGaN/AlN integrated photonics platform for the ultraviolet and visible spectral range.

    PubMed

    Soltani, Mohammad; Soref, Richard; Palacios, Tomas; Englund, Dirk

    2016-10-31

    We analyze a photonic integrated circuit (PIC) platform comprised of a crystalline AlxGa1-xN optical guiding layer on an AlN substrate for the ultraviolet to visible (UV-vis) wavelength range. An Al composition of x~0.65 provides a refractive index difference of ~0.1 between AlxGa1-xN and AlN, and a small lattice mismatch (< 1%) that minimizes crystal dislocations at the AlxGa1-xN/AlN interface. This small refractive index difference is beneficial at shorter wavelengths to avoid extra-small waveguide dimensions. The platform enables compact waveguides and bends with high field confinement in the wavelength range from 700 nm down to 300 nm (and potentially lower) with waveguide cross-section dimensions comparable to those used for telecom PICs such as silicon and silicon nitride waveguides, allowing for well-established optical lithography. This platform can potentially enable cost-effective, manufacturable, monolithic UV-vis photonic integrated circuits.

  6. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids have been observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. It was postulated that the voids resulted from an excess number of oxygen vacancies near the oxide-metal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidations of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al,Cr)2O3 and Ni(Al,Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationships between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  7. A novel Al matrix composite reinforced by nano-AlNp network.

    PubMed

    Ma, X; Zhao, Y F; Tian, W J; Qian, Z; Chen, H W; Wu, Y Y; Liu, X F

    2016-10-10

    In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The in-situ synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials.

  8. Wetting of polycrystalline SiC by molten Al and Al-Si alloys

    NASA Astrophysics Data System (ADS)

    Cong, Xiao-Shuang; Shen, Ping; Wang, Yi; Jiang, Qichuan

    2014-10-01

    The wetting of α-SiC by molten Al and Al-Si alloys was investigated using a dispensed sessile drop method in a high vacuum. In the Al-SiC system, representative wetting stages were identified. The liquid spreading was initially controlled by the deoxidation of the SiC surface and then by the formation of Al4C3 at the interface. The intrinsic contact angle for molten Al on the polycrystalline α-SiC surface was suggested to be lower than 90̊ provided that the oxide films covering the Al and SiC surfaces were removed, i.e., the system is partial wetting in nature. An increase in the Si concentration in liquid Al weakened the interfacial reaction but improved the final wettability. The role of the Si addition on the wetting was presumably attributed to its segregation at the interface and the formation of strong chemical bonds with the SiC surface.

  9. A novel Al matrix composite reinforced by nano-AlNp network

    NASA Astrophysics Data System (ADS)

    Ma, X.; Zhao, Y. F.; Tian, W. J.; Qian, Z.; Chen, H. W.; Wu, Y. Y.; Liu, X. F.

    2016-10-01

    In pursuit of lightweighting of automobiles and low emission of transportation, the efforts to develop high-strength, heat-resistant and fatigue-resistant Al alloys and/or composites have been ongoing. Here we report a novel Al matrix composite with ultrahigh strength reinforced by a three dimensional network of nano-AlN particles for the first time. The in-situ synthesized AlN particles are connected by twinning bonding chains and built up a three dimensional network strengthening Al matrix enormously like the skeleton to human body. The composite containing 16.4wt.% AlN particles shows excellent properties: the ultimate tensile strengths can be up to 518MPa at room temperature and 190MPa at 350 °C. This peculiar performance results from the novel spatial distribution of nano-scale AlN particles. Our findings in this work would help to develop a potential candidate for high-performance heat resistance light-metal based materials.

  10. Investigation of water assisted phase transformation process from AlPO4-5 to AlPO4-tridymite

    SciTech Connect

    Xu, Suochang; Zhao, Zhenchao; Hu, Mary Y.; Han, Xiuwen; Hu, Jian Zhi; Bao, Xinhe

    2016-03-01

    Water assisted phase transformation process from crystalized AlPO4-5 to AlPO4-tridymite was studied by the combination of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and in situ multinuclear MAS NMR. It is found that water first activates the residue amorphous aluminophosphate in crystalized AlPO4-5 sample through hydrolysis and condensation reactions. Then the activated aluminophosphate species reassemble into AlPO4-tridymite crystalline. Meanwhile, AlPO4-5 transforms into orthorhombic phase during heating process. With further crystallization of AlPO4-tridymite, the amorphous phase is gradually consumed, and mass transportation between AlPO4-5 and AlPO4-tridymite is established through gradually amorphization of AlPO4-5. Finally, most of the AlPO4-5 transforms into the thermodynamically stable dense phase AlPO4-tridymite.

  11. Electrochemical formation of Al-Tm intermetallics in eutectic LiCl-KCl melt containing Tm and Al ions

    NASA Astrophysics Data System (ADS)

    Li, Xing; Yan, Yong-De; Zhang, Mi-Lin; Tang, Hao; Ji, De-Bin; Han, Wei; Xue, Yun; Zhang, Zhi-Jian

    2014-09-01

    This work focuses on investigating the electrochemical formation of Al-Tm and Al-Li-Tm alloys in LiCl-KCl-AlCl3-Tm2O3 melt on both W and Al electrodes. Thermodynamic calculation and electrochemical behavior of LiCl-KCl melt containing both AlCl3 and Tm2O3 showed that AlCl3 can chlorinate Tm2O3 to release Tm(III) ions. Three kinds of Al-Tm intermetallics at about -1.26, -1.32 and -1.43 V were detected by means of various electrochemical measurement techniques, i.e. cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Potentiostatic and galvanostatic electrolysis were carried out on Al and W electrodes to prepare Al-Tm and Al-Li-Tm alloys, respectively. The composition of Al-Li-Tm alloys was analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES).

  12. Aberrant distributions of nuclear pore complex proteins in ALS mice and ALS patients.

    PubMed

    Shang, Jingwei; Yamashita, Toru; Nakano, Yumiko; Morihara, Ryuta; Li, Xianghong; Feng, Tian; Liu, Xia; Huang, Yong; Fukui, Yusuke; Hishikawa, Nozomi; Ohta, Yasuyuki; Abe, Koji

    2017-03-24

    Nuclear pore complexes (NPCs) play important roles in traffic of molecules between the nucleus and cytoplasm, aberrant distributions of components of NPCs were demonstrated in C9orf72 amyotrophic lateral sclerosis (C9-ALS) patients, but it is elusive whether such abnormities are also the case with other cause of ALS disease. In the present study, we investigated the spatiotemporal distributions of RanGAP1 and 4 representative nucleoporins (GP210, NUP205, NUP107 and NUP50) of NPCs in human Cu/Zn superoxide dismutase-1 mutation transgenic (SOD1-Tg) mice and sporadic ALS patients. Compared with wild type (WT), these proteins displayed age-dependent and progressive nuclear precipitations, and cytoplasmic aberrant expressions in motor neurons of lumbar cord in SOD1-Tg mice from 10 to 18weeks (W). Double immunofluorescent analysis showed abnormal nuclear retention and apparent co-localizations of RanGAPl with NUP205 and NUP205 with NUPl07, meanwhile, GP210 with NUP205 mainly co-localized in the nuclear envelope (NE) of motor neurons. Furthermore, RanGAP1, GP210 and NUP50 showed similarly abnormal nuclear precipitations and cytoplasmic upregulations in SOD1-Tg mice and ALS patients, moreover, aberrant co-localizations of RanGAP1 with TDP-43 and NUP205 with TDP-43 were also observed in motor neurons. The present study indicated that the mislocalization of these proteins of NPCs may underlie the pathogenesis of ALS both in SOD1-Tg mice and human sporadic ALS patients, and these dysfunctions may be a fundamental pathway for ALS that is not specific only in C9-ALS but also in SOD1-ALS, which may be amenable to pharmacotherapeutic intervention.

  13. An epidemiological study of cutaneous leishmaniasis in Al-jabal Al-gharbi, Libya.

    PubMed

    Abdellatif, Manal Z M; El-Mabrouk, Khamis; Ewis, Ashraf A

    2013-02-01

    Cutaneous leishmaniasis (CL) is an endemic parasitic infection in the Mediterranean region, including Libya and its Al-jabal Al-gharbi province. We aimed at studying the occupational relevance as well as other epidemiological aspects of CL. We investigated 140 CL cases who attended at Gharyan outpatient polyclinic during a period of 6 months in 2009. CL infection was clinically diagnosed and confirmed by demonstration of Leishmania parasites on smears from lesions. Our findings showed that males were more affected than females (P=0.04), and people above 10-years were more affected than younger ones (P=0.0001). A significant percent of CL cases belonged to Al-Kawasem subprovince (P=0.0001). Farm-related activities were the most frequent occupations among CL cases (P=0.04). In addition to farm workers, housewives and students are at risk groups since they are engaged at farm activities. Moreover, those who have occupations that require staying outdoors for a part of night, e.g., policemen, are also at risk. Compared to children, adult CL patients had multiple lesions (P=0.001) that were more prevalent in their upper and lower extremities than the face (P=0.0001). We conclude that CL is a major health problem in Al-jabal Al-gharbi province of Libya. The presence of rodents and sandflies makes it a suitable environment for Leishmania to spread in an endemic epidemiological pattern. Being engaged in farming activities or outdoor occupations increases the risk of infection. Various clinical patterns of CL suggest the presence of more than 1 species of Leishmania at Al-jabal Al-gharbi province. We propose that the 2 species responsible for CL in this area are L. major and L. tropica. Further investigations to identify the leishmanial species responsible for CL at Al-jabal Al-gharbi together with adoption of preventive and control programs are needed.

  14. An Epidemiological Study of Cutaneous Leishmaniasis in Al-Jabal Al-Gharbi, Libya

    PubMed Central

    Abdellatif, Manal Z. M.; El-Mabrouk, Khamis

    2013-01-01

    Cutaneous leishmaniasis (CL) is an endemic parasitic infection in the Mediterranean region, including Libya and its Al-jabal Al-gharbi province. We aimed at studying the occupational relevance as well as other epidemiological aspects of CL. We investigated 140 CL cases who attended at Gharyan outpatient polyclinic during a period of 6 months in 2009. CL infection was clinically diagnosed and confirmed by demonstration of Leishmania parasites on smears from lesions. Our findings showed that males were more affected than females (P=0.04), and people above 10-years were more affected than younger ones (P=0.0001). A significant percent of CL cases belonged to Al-Kawasem subprovince (P=0.0001). Farm-related activities were the most frequent occupations among CL cases (P=0.04). In addition to farm workers, housewives and students are at risk groups since they are engaged at farm activities. Moreover, those who have occupations that require staying outdoors for a part of night, e.g., policemen, are also at risk. Compared to children, adult CL patients had multiple lesions (P=0.001) that were more prevalent in their upper and lower extremities than the face (P=0.0001). We conclude that CL is a major health problem in Al-jabal Al-gharbi province of Libya. The presence of rodents and sandflies makes it a suitable environment for Leishmania to spread in an endemic epidemiological pattern. Being engaged in farming activities or outdoor occupations increases the risk of infection. Various clinical patterns of CL suggest the presence of more than 1 species of Leishmania at Al-jabal Al-gharbi province. We propose that the 2 species responsible for CL in this area are L. major and L. tropica. Further investigations to identify the leishmanial species responsible for CL at Al-jabal Al-gharbi together with adoption of preventive and control programs are needed. PMID:23467624

  15. Non-volatile Al2O3 Memory using Nanoscale Al-rich Al2O3 Thin Film as a Charge Storage Layer

    NASA Astrophysics Data System (ADS)

    Nakata, Shunji; Saito, Kunio; Shimada, Masaru

    2006-04-01

    This article describes the fabrication process and capacitance-voltage (C-V) characteristics of a new non-volatile Al2O3 memory with nanoscale thin film deposited by electron-cyclotron-resonance sputtering. Al-rich Al2O3 shows characteristics somewhere between Al and Al2O3 in the refractive index and wet etching rate. C-V characteristics of Al-rich Al2O3 memory show a large hysteresis window due to the Al-rich structure, while there is no hysteresis window in the case of stoichiometric Al2O3. This memory is expected to stay non-volatile for several years or more because the capacitance value after writing and erasing operation remained almost unchanged after 4 h at T=85 °C. Also, another new memory structure comprising SiO2/Al2O3 and the Al-rich Al2O3 structure is proposed, which features increased mobility due to the reduction of electron scattering at the Si/Al2O3 interface.

  16. Mechanochemical synthesis and crystal structure of alpha'-AlD3 and alpha-AlD3.

    PubMed

    Brinks, Hendrik W; Istad-Lem, Andreas; Hauback, Bjørn C

    2006-12-28

    AlD3 AlD3 was synthesized by ball milling of 3LiAlD4 + AlCl3. Planetary ball milling at room temperature resulted in a mixture of AlD3 (alpha and alpha') and Al in addition to LiCl, whereas cryomilling at 77 K resulted in only AlD3 and LiCl. The AlD3 obtained was a mixture of about 2/3alpha and 1/3alpha'. Alpha' was determined by powder neutron diffraction to take the beta-AlF3 structure with space group Cmcm and a = 6.470(3), b = 11.117(5), and c = 6.562(2) A. It is built up of corner-sharing AlD6 octahedra in an open structure with hexagonal holes of radius 3.9 A. Alpha' slowly decomposes during storage at 40 degrees C. Alpha-AlD3 is also described by a corner-sharing AlD6 network but in a more dense ReO3-type arrangement. Both AlD3 modifications have slightly shorter Al-D distances compared to Na3AlD6, Na2LiAlD6, and K2NaAlH6.

  17. Theoretical study of the vibrational properties of NaAlH4 with AlH3 vacancies

    NASA Astrophysics Data System (ADS)

    Chou, Mei-Yin; Zhang, Feng; Wang, Yan

    2011-03-01

    We investigate from first-principles calculations the vibrational properties in the presence of the AlH3 vacancy in both α and γ phases of NaAlH4 . When AlH3 is removed from an AlH4- anion, the remaining H recombines with another neighboring AlH4- anion and forms an AlH52 - unit with slightly deformed D3 h symmetry. For both α - and γ -NaAlH4 , the AlH3 vacancy induces several isolated phonon modes that are highly localized on the AlH52 - unit with frequencies within the band gap separating the Al-H stretching modes and Al-H bending modes in pure NaAlH4 . Similar localized phonon modes also exist in the gap separating the Al-H bending modes and the modes involving the rotation of AlH4- anions for the γ phase. On the other hand, for both α and γ phases of NaAlH4 with charged AlH4- vacancies, no isolated phonon modes were found to be localized in the vacancy region with frequencies within the band gap of the pure crystal. These theoretical findings suggest further experimental studies to identify the defects that are involved in the decomposition of NaAlH4 .

  18. Mechanical properties and electronic structures of Fe-Al intermetallic

    NASA Astrophysics Data System (ADS)

    Liu, YaHui; Chong, XiaoYu; Jiang, YeHua; Zhou, Rong; Feng, Jing

    2017-02-01

    Using the first-principles calculations, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe3Al, FeAl, FeAl2, Fe2Al5 and FeAl3) binary compounds were calculated. The formation enthalpy and cohesive energy of these Fe-Al compounds are negative, and show they are thermodynamically stable structures. Fe2Al5 has the lowest formation enthalpy, which shows the Fe2Al5 is the most stable of Fe-Al binary compounds. These Fe-Al compounds display disparate anisotropy due to the calculated different shape of the 3D curved surface of the Young's modulus and anisotropic index. Fe3Al has the biggest bulk modulus with the value 233.2 GPa. FeAl has the biggest Yong's modulus and shear modulus with the value 296.2 GPa and 119.8 GPa, respectively. The partial density of states, total density of states and electron density distribution maps of the binary Fe-Al binary compounds are analyzed. The bonding characteristics of these Fe-Al binary compounds are mainly combination by covalent bond and metallic bonds. Meanwhile, also exist anti-bond effect. Moreover, the Debye temperatures and sound velocity of these Fe-Al compounds are explored.

  19. When Validity Testing Lacks Validity: Comment on Levine et al.

    ERIC Educational Resources Information Center

    Kim, Min-Sun; Raja, Narayan S.

    2003-01-01

    Addresses each of the three main areas of Levine et al.'s (see this issue, CS 764 297) validity testing: mean differences in self-construals between Asians and Westerners and within individuals; priming experiments; and factor analysis of self-construal scales. Suggests that Levine et al.'s conclusions on crucial aspects of validity are untenable.…

  20. The dissociation energies of AlH 2 and AlAr

    NASA Astrophysics Data System (ADS)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Visscher, Luuk

    1995-11-01

    The D0 values for AlH 2 and AlAr are computed using the coupled cluster approach in conjunction with large basis sets. Basis set superposition and spin-orbit effects are accounted for, as they are significant due to the small binding energy. The computed dissociation energy ( D0) for AlAr is 114 cm -1, which is 93% of the experimental value (122.4 cm -1). Our best estimate for the AlH 2 binding energy is 38 ± 26 cm -1.

  1. Ferromagnetic ordering in NpAl2: Magnetic susceptibility and 27Al nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Martel, L.; Griveau, J.-C.; Eloirdi, R.; Selfslag, C.; Colineau, E.; Caciuffo, R.

    2015-08-01

    We report on the magnetic properties of the neptunium based ferromagnetic compound NpAl2. We used magnetization measurements and 27Al NMR spectroscopy to access magnetic features related to the paramagnetic and ordered states (TC=56 K). While very precise DC SQUID magnetization measurements confirm ferromagnetic ordering, they show a relatively small hysteresis loop at 5 K reduced with a coercive field HCo~3000 Oe. The variable offset cumulative spectra (VOCS) acquired in the paramagnetic state show a high sensitivity of the 27Al nuclei spectral parameters (Knight shifts and line broadening) to the ferromagnetic ordering, even at room temperature.

  2. Hot Corrosion Behavior of Stainless Steel with Al-Si/Al-Si-Cr Coating

    NASA Astrophysics Data System (ADS)

    Fu, Guangyan; Wu, Yongzhao; Liu, Qun; Li, Rongguang; Su, Yong

    2017-03-01

    The 1Cr18Ni9Ti stainless steel with Al-Si/Al-Si-Cr coatings is prepared by slurry process and vacuum diffusion, and the hot corrosion behavior of the stainless steel with/without the coatings is studied under the condition of Na2SO4 film at 950 °C in air. Results show that the corrosion kinetics of stainless steel, the stainless steel with Al-Si coating and the stainless steel with Al-Si-Cr coating follow parabolic laws in several segments. After 24 h corrosion, the sequence of the mass gain for the three alloys is the stainless steel with Al-Si-Cr coating < the stainless steel with Al-Si coating < the stainless steel without any coating. The corrosion products of the three alloys are layered. Thereinto, the corrosion products of stainless steel without coating are divided into two layers, where the outside layer contains a composite of Fe2O3 and FeO, and the inner layer is Cr2O3. The corrosion products of the stainless steel with Al-Si coating are also divided into two layers, of which the outside layer mainly consists of Cr2O3, and the inner layer is mainly SiO2. The corrosion film of the stainless steel with Al-Si-Cr coating is thin and dense, which combines well with substrate. Thereinto, the outside layer is mainly Cr2O3, and the inside layer is Al2O3. In the matrix of all of the three alloys, there exist small amount of sulfides. Continuous and protective films of Cr2O3, SiO2 and Al2O3 form on the surface of the stainless steel with Al-Si and Al-Si-Cr coatings, which prevent further oxidation or sulfide corrosion of matrix metals, and this is the main reason for the much smaller mass gain of the two alloys than that of the stainless steel without any coatings in the 24 h hot corrosion process.

  3. Corrosion Fatigue of Al-Zn-Mg and and Al-Mg-Li Alloys.

    DTIC Science & Technology

    1986-01-01

    surface of a sample of the Al-Zn-Mg alloy tested in 0.5 M sodium chloride, at a constant potential of -0.8 I..* xiii ..:S: Vuce ...potential of -0.8 Vuce (10OX). 20g .71 179 eL 4 0.2 mm Figure 97 The fracture surface of a sample of the Al-Zn-Mg alloy tested in 0.5 N sodium...fracture surface of a sample of the Al-Zn-Mg alloy tested in 0.5 N sodium chloride at a constant potential of-1.0 Vuce (20X). : Figure 100 The fracture

  4. Superconductivity of Al/Al2O3 interface formed under shock-wave conditions

    NASA Astrophysics Data System (ADS)

    Shakhray, D. V.; Avdonin, V. V.; Palnichenko, A. V.; Vyaselev, O. M.

    2015-11-01

    A mixture of powdered Al and Al2O3 has been subjected to a shock-wave pressure of ≈ 170 kbar, followed by vacuum-encapsulating and quenching of the product to liquid nitrogen. The ac magnetic susceptibility measurements of the samples have revealed metastable superconductivity with Tc ≈ 37 K, characterized by glassy dynamics of the shielding currents below Tc. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed between metallic Al and its oxide due to the shock-wave treatment.

  5. Revisiting Deng et al.'s Multiparty Quantum Secret Sharing Protocol

    NASA Astrophysics Data System (ADS)

    Hwang, Tzonelih; Hwang, Cheng-Chieh; Yang, Chun-Wei; Li, Chuan-Ming

    2011-09-01

    The multiparty quantum secret sharing protocol [Deng et al. in Chin. Phys. Lett. 23: 1084-1087, 2006] is revisited in this study. It is found that the performance of Deng et al.'s protocol can be much improved by using the techniques of block-transmission and decoy single photons. As a result, the qubit efficiency is improved 2.4 times and only one classical communication, a public discussion, and two quantum communications between each agent and the secret holder are needed rather than n classical communications, n public discussions, and 3n/2 quantum communications required in the original scheme.

  6. Metal clusters with hidden ground states: Melting and structural transitions in Al115(+), Al116(+), and Al117(+).

    PubMed

    Cao, Baopeng; Starace, Anne K; Judd, Oscar H; Bhattacharyya, Indrani; Jarrold, Martin F

    2009-09-28

    Heat capacities measured as a function of temperature for Al(115)(+), Al(116)(+), and Al(117)(+) show two well-resolved peaks, at around 450 and 600 K. After being annealed to 523 K (a temperature between the two peaks) or to 773 K (well above both peaks), the high temperature peak remains unchanged but the low temperature peak disappears. After considering the possible explanations, the low temperature peak is attributed to a structural transition and the high temperature peak to the melting of the higher enthalpy structure generated by the structural transition. The annealing results show that the liquid clusters freeze exclusively into the higher enthalpy structure and that the lower enthalpy structure is not accessible from the higher enthalpy one on the timescale of the experiments. We suggest that the low enthalpy structure observed before annealing results from epitaxy, where the smaller clusters act as a nucleus and follow a growth pattern that provides access to the low enthalpy structure. The solid-to-solid transition that leads to the low temperature peak in the heat capacity does not occur under equilibrium but requires a superheated solid.

  7. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-13

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  8. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    SciTech Connect

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-13

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  9. Core-excitonic lines at the Al 2p surface optical-absorption threshold of AlAs and AlP

    NASA Astrophysics Data System (ADS)

    Kelly, M. K.; Niles, D. W.; Perfetti, P.; Colavita, E.; Savoia, A.; Margaritondo, G.; Henzler, M.

    1985-10-01

    The optical-absorption spectra of AlAs and AlP exhibit unusual features-strong Al 2p core-excitonic lines. The data were obtained with synchrotron-radiation photoemission in the partial-yield mode. The analysis was based on the approach proposed by Johnson, Fock, Ley, and Cardona for AlSb and on Onodera and Toyozawa's exciton theory.

  10. Adherent Al2O3 scales produced on undoped NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    1986-01-01

    Repeated oxidation and polishing of high purity Ni-15Cr-13Al has dramatically changed its cyclic oxidation behavior from nonadherent to adherent. No apparent change in scale phase, morphology or interface structure occurred during this transition, dismissing any mechanism based on pegging, vacancy sink, or growth stress. The principle change that did occur was a reduction in the sulfur content from 10 ppmw to 3 ppmw after 25 cycles at 1120 C. These observations are used to support the model of Al2O3 scale adherence put forth by Smeggil et al. which claims that Al2O3 scale spallation occurs due to sulfur segregation and bond deterioration at the oxide-metal interface.

  11. Proximity effect and interface transparency in Al/InAs-nanowire/Al diffusive junctions

    NASA Astrophysics Data System (ADS)

    Bubis, A. V.; Denisov, A. O.; Piatrusha, S. U.; Batov, I. E.; Khrapai, V. S.; Becker, J.; Treu, J.; Ruhstorfer, D.; Koblmüller, G.

    2017-09-01

    We investigate the proximity effect in InAs nanowire (NW) junctions with superconducting contacts made of Al. The carrier density in InAs is tuned by means of the back gate voltage V g. At high positive V g the devices feature transport signatures characteristic of diffusive junctions with highly transparent interfaces—sizable excess current, re-entrant resistance effect and proximity gap values ({{{Δ }}}N) close to the Al gap ({{{Δ }}}0). At decreasing V g, we observe a reduction of the proximity gap down to {{{Δ }}}N≈ {{{Δ }}}0/2 at NW conductances ∼ 2 {{{e}}}2 {{{h}}}-1, which is interpreted in terms of carrier density dependent reduction of the Al/InAs interface transparency. We demonstrate that the experimental behavior of {{{Δ }}}N is closely reproduced by a model with rectangular potential barrier at the Al/InAs interface.

  12. Interdiffusion in the Mg-Al system and Intrinsic Diffusion in (Al3Mg2) Phase

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S; Sohn, Yong Ho

    2011-01-01

    Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics -Al12Mg17 and -Al3Mg2, but not -phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  13. High quality UV AlGaN/AlGaN distributed Bragg reflectors and microcavities

    NASA Astrophysics Data System (ADS)

    Mitrofanov, Oleg; Schmult, S.; Manfra, M. J.; Siegrist, T.; Weimann, N. G.; Sergent, A. M.; Molnar, R. J.

    2007-02-01

    We demonstrate high-reflectivity crack-free Al 0.18Ga 0.82N/Al 0.8Ga 0.2N distributed Bragg reflectors (DBR) and monolithic microcavities grown by molecular beam epitaxy on thick c-axis GaN templates. The elastic strain energy in the epilayer is minimized by compensating the compressive and tensile stress in every period of the DBR structure. A 25 period DBR mirror provides a 26nm-wide stop band centered at 347 nm with the maximum reflectivity higher than 99%. The high-reflectivity DBRs can be used to form high Q-factor monolithic AlGaN/AlGaN microcavities.

  14. 'Abd al-Rahman al-Sufi's 3-Step Magnitude System

    NASA Astrophysics Data System (ADS)

    Hafez, Ihsan; Stephenson, F. Richard; Orchiston, Wayne

    'Abd al-Rahmān al-ūfī's Book of the Fixed Stars dates from around AD 964 and is one of the most important medieval Arabic treatises on astronomy. In this paper we begin with a very brief introduction to the Book of the Fixed Stars. This book contains an extensive star catalogue that lists star coordinates and magnitude estimates for all of the Ptolemaic stars. However, in his book al-hūfī utilized three distinct intermediate magnitude values whereas Ptolemy only mentioned two. We believe that al-hūfī used what we have termed a '3-step intermediate magnitude system,' which is more accurate than Ptolemy's 2-step intermediate system. In this paper we examine in detail the accuracy of this unique 3-step system in comparison with Ptolemy's and modern magnitude values.

  15. Room-Temperature Quantum Ballistic Transport in Monolithic Ultrascaled Al-Ge-Al Nanowire Heterostructures.

    PubMed

    Sistani, Masiar; Staudinger, Philipp; Greil, Johannes; Holzbauer, Martin; Detz, Hermann; Bertagnolli, Emmerich; Lugstein, Alois

    2017-08-09

    Conductance quantization at room temperature is a key requirement for the utilizing of ballistic transport for, e.g., high-performance, low-power dissipating transistors operating at the upper limit of "on"-state conductance or multivalued logic gates. So far, studying conductance quantization has been restricted to high-mobility materials at ultralow temperatures and requires sophisticated nanostructure formation techniques and precise lithography for contact formation. Utilizing a thermally induced exchange reaction between single-crystalline Ge nanowires and Al pads, we achieved monolithic Al-Ge-Al NW heterostructures with ultrasmall Ge segments contacted by self-aligned quasi one-dimensional crystalline Al leads. By integration in electrostatically modulated back-gated field-effect transistors, we demonstrate the first experimental observation of room temperature quantum ballistic transport in Ge, favorable for integration in complementary metal-oxide-semiconductor platform technology.

  16. Fabrication of Fe-Al nanoparticles by selective oxidation of Fe-Al thin films

    NASA Astrophysics Data System (ADS)

    Jang, Pyungwoo; Shin, Seungchan; Jung, Chip-Sup; Kim, Kwang-Ho; Seomoon, Kyu

    2013-04-01

    The possibility of a new technique for fabricating nanoparticles from thin films using selective oxidation in an atmosphere mixture of water vapor and hydrogen was investigated. Fe-5wt.%Al films were RF-sputtered and annealed in the atmosphere mixture at 900°C for up to 200 min, in order to oxidize aluminum selectively. Thermodynamics simulation showed that temperatures exceeding 800°C are necessary to prevent iron from being oxidized, as confirmed by the depth profile of XPS. As the annealing time increased, the morphology of the 200-nm Fe-Al films changed from the continuous to the discontinuous type; thus, particulate Fe-Al films formed after 100 min. The particulate 10- to 100-nm Fe-Al films showed super-paramagnetic behavior after the oxidation. Thus, a new technique for fabricating nanoparticles was successfully introduced using selective oxidation.

  17. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  18. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  19. Local stress-induced effects on AlGaAs/AlOx oxidation front shape

    SciTech Connect

    Chouchane, F.; Almuneau, G. Arnoult, A.; Lacoste, G.; Fontaine, C.; Cherkashin, N.

    2014-07-28

    The lateral oxidation of thick AlGaAs layers (>500 nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized Al{sub x}Ga{sub 1−x}As/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.

  20. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Viswanathan, S.; Santella, M.L.

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, and wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.

  1. Ni{sub 3}Al technology transfer

    SciTech Connect

    Sikka, V.K.; Santella, M.L.; Alexander, D.J.

    1995-05-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for (1)high-strength castable composition for turbochargers, furnace furniture, and hot-die applications; (2) castability (fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) hot fabricability of cast ingots. All of the issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes work completed to address some of these issues during the fourth quarter of FY 1994.

  2. The β-decay of 22Al

    NASA Astrophysics Data System (ADS)

    Achouri, N. L.; de Oliveira Santos, F.; Lewitowicz, M.; Blank, B.; Äystö, J.; Canchel, G.; Czajkowski, S.; Dendooven, P.; Emsallem, A.; Giovinazzo, J.; Guillet, N.; Jokinen, A.; Laird, A. M.; Longour, C.; Peräjärvi, K.; Smirnova, N.; Stanoiu, M.; Thomas, J.-C.

    2006-03-01

    In an experiment performed at the LISE3 facility of GANIL, we studied the decay of 22Al produced by the fragmentation of a 36Ar primary beam. A β-decay half-life of T 1/2 = 91.1±0.5ms was measured. The β-delayed one- and two-proton emission as well as β-α and β-delayed γ-decays were measured and allowed us to establish a partial decay scheme for this nucleus. New levels were determined in the daughter nucleus 22Mg. The comparison with model calculations strongly favours a spin-parity of I π = 4+ for the ground state of 22Al.

  3. Observable Proxies For 26 Al Enhancement

    SciTech Connect

    Fryer, Christopher L; Young, Patrick A; Ellinger, Carola I; Arnett, William D

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  4. DFT study of Al doped armchair SWCNTs

    SciTech Connect

    Dhiman, Shobhna; Rani, Anita; Kumar, Ranjan; Dharamvir, Keya

    2016-05-23

    Electronic properties of endohedrally doped armchair single-walled carbon nanotubes (SWCNTs) with a chain of six Al atoms have been studied using ab-initio density functional theory. We investigate the binding energy/atom, ionization potential, electron Affinity and Homo-Lumo gap of doped armchair SWNTs from (4,4) to (6,6) with two ends open. BE/dopant atom and ionization potential is maximum for (6, 6) doped armchair carbon nanotube; suggest that it is more stable than (4, 4) and (5, 5) doped tubes. HOMO - LUMO gap of Al doped arm chair carbon nanotubes decreases linearly with the increase in diameter of the tube. This shows that confinement induce a strong effect on electronic properties of doped tubes. These combined systems can be used for future nano electronics. The ab–initio calculations were performed with SIESTA code using generalized gradient approximation (GGA).

  5. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1979-01-01

    Cold pressing and sintering techniques were used to produce ceramic test specimens in which the major phase was either Si3N4 or a solid solution having the beta Si3N4 structure. Additional components were incorporated to promote liquid phase sintering. Glass and/or crystalline phase were consequently retained in boundaries between Si3N4 grains which largely determined the physical properties of the bodies. Systems investigated most extensively included R-Si-Al-O-N (R = rare earth element) Zr-Si-Al-O-N, Y-Si-Be-O-N, and R1-R2-Si-O-N. Room temperature and 1370 C modulus of ruptured, 1370 C creep, and oxidation behavior are discussed in terms of phase relationships in a parent quinery, and relavent oxide systems.

  6. Impact of superbends at the ALS

    SciTech Connect

    Nishimura, H.; Robin, D.

    1999-03-19

    To satisfy a demand for high energy, high brightness x-ray sources at the Advanced Light Source (ALS), a plan is in place to replace three 1.3 Tesla normal conducting bending magnets with three 5 Tesla superconducting magnets (superbends) in the year 2001. In this paper they discuss the impact of the superbends on the ALS beam parameters and particle dynamics. In particular they show the effect on the emittance, energy spread, and lifetime. They find that by adjusting the dispersion to be positive in the straight section they are able to largely restore the horizontal emittance. The vertical emittance can be adjusted independently to control the lifetime. The particle dynamics are investigated through particle tracking with a frequency analysis postprocessor. They find that by placing the three superbends symmetrically around the ring there is ample dynamic aperture for injection and lifetime.

  7. Forging of FeAl intermetallic compounds

    SciTech Connect

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L.; Schneibel, J.H.

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  8. Investigation of Phase Equilibria and Some Properties of Alloys of Ti-Al-Fe and Ti-Al-V Systems,

    DTIC Science & Technology

    Some data on the structure and properties of Ti-Al-Fe alloys are presented. The phase equilibria in alloys in the system Ti-Al-V were studies...However, the data available in the literature on phase equilibria in the systems Ti-Al-Fe and Ti-Al-V require refinement, as they are insufficiently

  9. Bulk Al-Al3Zr composite prepared by mechanical alloying and hot extrusion for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Pourkhorshid, E.; Enayati, M. H.; Sabooni, S.; Karimzadeh, F.; Paydar, M. H.

    2017-08-01

    Bulk Al/Al3Zr composite was prepared by a combination of mechanical alloying (MA) and hot extrusion processes. Elemental Al and Zr powders were milled for up to 10 h and heat treated at 600°C for 1 h to form stable Al3Zr. The prepared Al3Zr powder was then mixed with the pure Al powder to produce an Al-Al3Zr composite. The composite powder was finally consolidated by hot extrusion at 550°C. The mechanical properties of consolidated samples were evaluated by hardness and tension tests at room and elevated temperatures. The results show that annealing of the 10-h-milled powder at 600°C for 1 h led to the formation of a stable Al3Zr phase. Differential scanning calorimetry (DSC) results confirmed that the formation of Al3Zr began with the nucleation of a metastable phase, which subsequently transformed to the stable tetragonal Al3Zr structure. The tension yield strength of the Al-10wt%Al3Zr composite was determined to be 103 MPa, which is approximately twice that for pure Al (53 MPa). The yield stress of the Al/Al3Zr composite at 300°C is just 10% lower than that at room temperature, which demonstrates the strong potential for the prepared composite to be used in high-temperature structural applications.

  10. State of Digital Education Options in the areas of Medical Terminology and the History, Theory and Ethics of Medicine.

    PubMed

    Schochow, Maximilian; Steger, Florian

    2015-01-01

    Hintergrund: In Deutschland haben viele Einrichtungen für die Bereiche Geschichte, Theorie und Ethik der Medizin E-Learning-Angebote produziert, die auf unterschiedlichen Lernplattformen basieren (LMS) und spezifisch auf die jeweilige curriculare Präsenzlehre zugeschnitten sind. Bisher existieren keine validen Daten darüber, welche Einrichtungen E-Learning-Angebote bereitstellen und welche Formen des E-Learning diese anbieten.Methoden: Von den 31 deutschen Einrichtungen für Geschichte, Theorie und Ethik der Medizin, die gefragt wurden, den Fragebogen auszufüllen, haben 30 geantwortet, was einer Rücklaufquote von 97% entspricht. Die telefonische Befragung fand zwischen Juli und August 2012 statt.Ergebnisse: Der Einsatz digitaler interaktiver Lehrmaterialien, die webbasiert den Studierenden zur Verfügung gestellt werden, hat in den vergangenen Jahren eine Konjunktur an deutschen Einrichtungen für die Bereiche Geschichte, Theorie und Ethik der Medizin erfahren. Dieser Trend wird sich weiter fortsetzen, da mehr als die Hälfte (67%) der Einrichtungen ihre bisherigen E-Learning-Angebote ausbauen will. In den vergangenen Jahren sind vor allem Angebote für Medizinische Terminologie entstanden. Viele Einrichtungen möchten künftig ihre Angebote für Medizinische Terminologie weiterentwickeln. Insgesamt wurden die E-Learning-Angebote von den Studierenden sehr gut aufgenommen. 57% der Einrichtungen gaben an, dass 90-100% der Studierenden die Angebote regelmäßig nutzen.Schlussfolgerungen: Dieser Artikel diskutiert die Ergebnisse einer umfangreichen empirischen Studie über E-Learning. Er zeigt den Rahmen auf, in dem deutsche Einrichtungen vorhaben, ihre E-Learning-Optionen in der Zukunft auszuweiten. Schließlich werden spezifische Vorschläge für die Zusammenarbeit unter den Einrichtungen (nicht nur online) gemacht, deren Ziel es ist, Synergien im Bereich E-Learning zu erzeugen.

  11. Differential expression of MMP-2, MMP-9 and TIMP proteins in thoracic aortic aneurysm - comparison with and without bicuspid aortic valve: a meta-analysis.

    PubMed

    Rabkin, Simon W

    2014-11-01

    Hintergrund: Es wird angenommen, dass das Gleichgewicht der Matrix- Metalloproteasen (MMPs) und der Gewebeinhibitoren von Metalloproteinasen (TIMPs ) in der Aorta eine entscheidende Rolle bei der Ausbildung von Aneurysmen spielt. Das Ziel dieser Studie war es, eine Meta-Analyse von Studien durchzuführen, die die Protein-Expression von MMPs und TIMPs bei Aneurysmen der Aorta ascendens (TAA) untersuchten. Dabei sollte zwischen trikuspiden (TAV) und bikuspiden Aortenklappen (BAV) unterschieden werden. Methoden: Medline und Embase OvidSP wurden systematisch nach Studien abgefragt, die MMPs oder TIMPs aus TAAs und Kontrollen untersuchten. Eine entsprechende Suche erfolgte zum Vergleich zwischen BAV und TAV. Ergebnisse: Acht Studien erfüllten die Einschlusskriterien. Es gab einen signifikanten Anstieg der MMP-9 und keine Veränderung in MMP-2 in der Aorta von Personen mit TAA (N = 106 ) im Vergleich zur Kontrolle (n = 30). Zudem gab es eine hochsignifikante Verringerung der TIMP-1 und TIMP-2 in TAA (N = 93) im Vergleich zur Kontrolle (n = 24 ), was zu einem MMP-9 zu TIMP-1 oder TIMP-2-Verhältnis von mehr als 3,5 im Vergleich zu Kontrollen führte. Es fand sich eine hochsignifikante Erhöhung der MMP-2, aber nicht der MMP-9 in TAAs mit BAV (N = 112 ) im Vergleich zu TAV (N = 53). Es gab eine signifikante Reduktion von TIMP-1 bei BAV im Vergleich zu TAV, aber keine Änderung von TIMP-2, TIMP-3 oder TIMP-4 . Schlussfolgerungen: Diese Daten deuten darauf hin, dass MMP eine Rolle in der Pathogenese von TAA spielt. Es gibt eine unterschiedliche Expression mit erhöhtem MMP-9 und verminderten TIMP-1 und -2 bei den häufigsten Formen des TAA. MMP-2 ist erhöht und nur TIMP-1 vermindert bei TAA mit BAV im Vergleich zu TAV.

  12. Technische Systeme für den Herzersatz und die Herzunterstützung

    NASA Astrophysics Data System (ADS)

    Schöb, Reto; Loree, Howard M.

    Herzkrankheiten verursachen allein in den Vereinigten Staaten jährlich mehr als 700’000 Todesfälle. Ungefähr 3 Millionen Patienten in den U.S.A. leiden gemäss der American Heart Association (AHA) und dem National Heart, Lung and Blood Institute (NHLBI) an kongestivem Herzversagen (Congestive Heart Failure, CHF), welches eine chronische, sehr entkräftende und degenerative Krankheit ist: Das Herz ist dabei unfähig, hinreichend Blut zu den Organen des Körpers zu pumpen. Über 400’000 Fälle von CHF werden jedes Jahr diagnostiziert. Ähnliche Zahlen werden für Europa und Japan zusammen geschätzt. Basierend auf Daten vom AHA und NHLBI beträgt die fünfjährige Überlebensrate für CHF-Patienten lediglich etwa 50% [1]. 70’000-120’000 dieser Patienten könnten von einer Herzverpflanzung profitieren. 1999 wurden in den USA aber nur 2185 Herztransplantationen durchgeführt während die Warteliste über 4000 Patienten beträgt [2]. Ein akuter Mangel an Spenderherzen und die enormen Kosten (250’000-400’000 USD pro Patient) sind die begrenzenden Faktoren für Herztransplantationen [3]. Dies bedeutet, dass eine riesige Anzahl von Patienten durch ein zuverlässiges und verschleissfreies, nichtthrombotisches, total implantierbares, künstliches Herz gerettet werden könnten. Bis heute jedoch kein derartiges Implantat kommerziell verfügbar.

  13. Energieeffizienz im Verkehr

    NASA Astrophysics Data System (ADS)

    Helms, Hinrich; Lambrecht, Udo; Hanusch, Jan

    Mobilität - also Beweglichkeit - kennzeichnet unsere Gesellschaft heute mehr als je zuvor. So können und müssen viele individuelle Bedürfnisse nicht mehr direkt am Wohnort, sondern an anderen Orten erfüllt werden. Mobilität kann in diesem Kontext auch definiert werden als " die Möglichkeit, durch Ortsveränderung Interessen realisieren zu können.“ (SRU 2005). Oft führt eine hohe Mobilität auch zu hohem Verkehrsaufkommen, wobei Verkehr dabei als tatsächliche Ortsveränderung verstanden wird (realisierte Mobilität).

  14. Structure and ductility of TiAl

    SciTech Connect

    Imayev, R.; Salishchev, G.; Imayev, V.; Shagiev, M.; Kuznetzov, A.

    1995-12-31

    The effect of structural factors (grain size and grain boundary structure) and strain rate on the deformation mechanism and ductility of TiAl in the temperature range of brittle-to-ductile transition and at room temperature was systematically investigated. It has been established that it is possible to substantially affect the deformation mechanism and ductility of this intermetallic by controlling structural factors, particularly the grain size, and varying the strain rate.

  15. Methodological comments: McFarlane et al.

    PubMed

    Kraemer, Helena Chmura

    2015-01-01

    Does the McFarlane et al study provide a model for practical trials? Unfortunately, not. The methodological problems are here reviewed and used as a springboard to set out methodological criteria that might define such a model. © The Author 2014. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Al Qaeda as a Charismatic Phenomenon

    DTIC Science & Technology

    2009-06-01

    QUESTIONS Scholars’ frequent use of the concept of charisma in the study of social revolutions, terrorist, and insurgent movements gives rise to the...frequent use of charisma to explain collective behavior in the study of social revolutions, terrorist, and insurgent movements gives rise to the thesis...that Osama bin Laden has used his ability to finance or bankroll terrorist operations as a means to exercise control in Al Qaeda.204 In fact, Rolland

  17. Psychosocial adjustment to ALS: a longitudinal study.

    PubMed

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS.

  18. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS. PMID:26441696

  19. An Al Qaeda Way of War

    DTIC Science & Technology

    2012-05-17

    information on water supply and wastewater management practices in the U.S. and abroad. There has also been interest in insecticides and pest control ...no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control ...members have sought information on Supervisory Control and Data Acquisition systems available on multiple web sites. [Al Qaeda] specifically sought

  20. Hypermetabolism as a Risk Factor for ALS

    DTIC Science & Technology

    2012-07-01

    4 Introduction Amyotrophic Lateral Sclerosis (ALS), a neurodegenerative disorder characterized by the progressive loss of motor...Gonzalez de Aguilar JL, & Loeffler JP: Evidence for defective energy homeostasis in amyotrophic lateral sclerosis : benefit of a high-energy diet in a...and supplements in amyotrophic lateral sclerosis and other neurodegenerative disorders. Curr Opin Clin Nutr Metab Care 6:631- 43, 2002. 8. Lagier

  1. Hypermetabolism as a Risk Factor for ALS

    DTIC Science & Technology

    2013-09-01

    Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis . Science 314, 130–133 (2006). 2. Weihl, C. C. et al. TDP-43...body fat, likely working through a protein called Tbc1d1 which is known to control fat metabolism in skeletal muscle . To test this hypothesis, we...generated conditional Tdp-43 knockout mice using a muscle -specific (MLC) driver of Cre recombinase. Loss of Tdp-43 in skeletal muscle led to adult onset

  2. Al Kazim Water Supply, Nassriya, Iraq

    DTIC Science & Technology

    2008-07-23

    water network a perimeter fence Project Assessment Objectives. The objective of this project assessment was to provide real-time information...network connecting to the existing water network . To date, the Al Kazim Water Supply project results are consistent with the original contract...treatment plant, an above ground storage reservoir, a pipe network connecting to the existing water network , and an approximately 160 linear meter

  3. Al Ager Water Compact Unit, Nassriya, Iraq

    DTIC Science & Technology

    2008-07-22

    plant was to contain a reverse osmosis unit, an above-ground storage reservoir, a pipe network connecting to the existing water network , and a...the existing water network , and a perimeter fence for the new facility. To date, the Al Ager Water Compact Unit project results are consistent with...of 110 millimeter (mm) polyvinyl chloride (PVC), connection to the existing water network , and a perimeter fence measuring approximately 50-m x 30-m

  4. Neutron spectroscopy of γ-AlH3

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Alexander; Graetz, Jason; Jensen, Craig; Langley, Walker; Antonov, Vladimir

    2009-03-01

    The density of vibrational states, G(E), for γ-AlH3 is measured by inelastic neutron scattering. The obtained spectrum noticeably differs from that of α-AlH3, because α-AlH3 has a structure built of corner-sharing AlH6 octahedra, while the γ-AlH3 is composed of both corner- and edge-sharing AlH6 octahedra. The first acoustic phonon peak in the G(E) of γ-AlH3 appears at a lower energy and the band of translational modes extends to higher energies (55 vs. 42 meV) than in the spectrum of α-AlH3. The bands of Al-H bending modes are observed at about the same energies of 60--140 meV in γ-AlH3 and α-AlH3, only the structures of the bands are different. The Al-H stretching modes in the γ-phase show eight peaks in the range 145 to 265 meV, while in the α-phase they exhibits only two peaks at 200 and 235 meV. The G(E) spectrum of γ-AlH3 is in good agreement with recent simulations [Y. Wang et al., Phys. Rev. B 77 (2008) 014101], which took into account the existence of a unique double-bridge bond between certain Al and H atoms.

  5. Transmission electron microscopy studies of squeeze cast Al-AlN composites.

    PubMed

    Chédru, M.; Vicens, J.; Chermant, J. L.; Mordike, B. L.

    2001-02-01

    Aluminium-matrix composites containing approximately 45 vol.% AlN particles were fabricated by melt infiltration of aluminium into an AlN preform under a pressure up to 130 MPa. Three types of aluminium alloy (2024, 6060 and 5754) were used. The as-prepared composites were studied by light microscopy, scanning and transmission electron microscopies, and energy-dispersive X-ray spectroscopy. As a result of the melt infiltration process, the composites are very dense and the microstructure shows a homogeneous distribution of the reinforcement. The interfaces are clean with very little porosity. Composites with 2024 and 6060 matrices were carefully studied by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) after heat treatments. Dislocation density in the matrix of the reinforced material increases due to the difference in thermal expansion coefficients of aluminium alloys and AlN. This can induce an accelerated ageing response of the coherent and semicoherent precipitations of age-hardened matrices. This behaviour has been studied in the 2024 and 6060 composites by using microhardness measurements and TEM. Reactions between the AlN reinforcement and aluminium matrices (6060 and 5754) were observed and analysed by TEM. Matrices containing some of magnesium display a MgAl2O4 spinel formation at the AlN/matrix interface. The spinel formation is probably due to the reaction between magnesium of the matrix and the thin Al2O3 layer on the AlN surfaces. This reaction can affect the mechanical behaviour of the composite infiltrated with the 5754 matrix. This has been confirmed by overageing some samples at high temperatures (300 degrees C and 550 degrees C) for 10 days in order to emphasize the interfacial reactions.

  6. Toughening mechanisms in Al/Al-SiC laminated metal composites

    SciTech Connect

    Lesuer, D.R.; Wadsworth, J.; Riddle, R.A.; Syn, C.K.; Lewandowski, J.J.; Hunt, W.H. Jr.

    1996-12-31

    The fracture toughness of laminated metal composites consisting of alternating layers of a metal matrix composite (Al6090/SiC/25p) and a monolithic aluminum alloy (Al5182) has been studied as a function of the volume fraction of the component materials. Finite element simulations of the fracture toughness tests have been used to study the mechanisms of crack growth and extrinsic toughening. The mechanisms responsible for toughening in laminated metal composites are described.

  7. Structure and mechanical behavior of Al-Al4C3 composites

    NASA Astrophysics Data System (ADS)

    Kulkov, S. N.; Vorozhtsov, S. A.

    2011-04-01

    Results obtained from an x-ray phase analysis and mechanical tests on compression of hot-pressed Al-Al 4 C 3 composites with 5 or 10 wt.% C added to the initial powder mixture are presented. It is shown that the higher is the amount of aluminum carbide formed under hot pressing, the higher are the yield stress and the effective elastic modulus of the composite.

  8. Three-Dimensional FIB/EBSD Characterization of Irradiated HfAl3-Al Composite

    SciTech Connect

    Hua, Zilong; Guillen, Donna Post; Harris, William; Ban, Heng

    2016-09-01

    A thermal neutron absorbing material, comprised of 28.4 vol% HfAl3 in an Al matrix, was developed to serve as a conductively cooled thermal neutron filter to enable fast flux materials and fuels testing in a pressurized water reactor. In order to observe the microstructural change of the HfAl3-Al composite due to neutron irradiation, an EBSD-FIB characterization approach is developed and presented in this paper. Using the focused ion beam (FIB), the sample was fabricated to 25µm × 25µm × 20 µm and mounted on the grid. A series of operations were carried out repetitively on the sample top surface to prepare it for scanning electron microscopy (SEM). First, a ~100-nm layer was removed by high voltage FIB milling. Then, several cleaning passes were performed on the newly exposed surface using low voltage FIB milling to improve the SEM image quality. Last, the surface was scanned by Electron Backscattering Diffraction (EBSD) to obtain the two-dimensional image. After 50 to 100 two-dimensional images were collected, the images were stacked to reconstruct a three-dimensional model using DREAM.3D software. Two such reconstructed three-dimensional models were obtained from samples of the original and post-irradiation HfAl3-Al composite respectively, from which the most significant microstructural change caused by neutron irradiation apparently is the size reduction of both HfAl3 and Al grains. The possible reason is the thermal expansion and related thermal strain from the thermal neutron absorption. This technique can be applied to three-dimensional microstructure characterization of irradiated materials.

  9. Energetic ion bombarded Fe/Al multilayers

    SciTech Connect

    Al-Busaidy, M.S.; Crapper, M.D.

    2006-05-15

    The utility of ion-assisted deposition is investigated to explore the possibility of counteracting the deficiency of back-reflected current of Ar neutrals in the case of lighter elements such as Al. A range of energetically ion bombarded Fe/Al multilayers sputtered with applied surface bias of 0, -200, or -400 V were deposited onto Si(111) substrates in an argon atmosphere of 4 mTorr using a computer controlled dc magnetron sputtering system. Grazing incidence reflectivity and rocking curve scans by synchrotron x rays of wavelength of 1.38 A were used to investigate the structures of the interfaces produced. Substantial evidence has been gathered to suggest the gradual suppression of interfacial mixing and reduction in interfacial roughness with increases of applied bias. The densification of the Al microstructure was noticeable and may be a consequence of resputtering attributable to the induced ion bombardment. The average interfacial roughnesses were calculated for the 0, -200, and -400 V samples to be 7{+-}0.5, 6{+-}0.5, and 5{+-}0.5 A respectfully demonstrating a 30% improvement in interface quality. Data from rocking curve scans point to improved long-range correlated roughness in energetically deposited samples. The computational code based on the recursive algorithm developed by Parratt [Phys. Rev. 95, 359 (1954)] was successful in the simulation of the specular reflectivity curves.

  10. Dielectronic Recombination of Al-Like Ions

    NASA Astrophysics Data System (ADS)

    Abdel-Naby, Shahin; Nikolic, Dragan; Gorczyca, Thomas W.; Badnell, Nigel R.; Savin, Daniel W.

    2008-05-01

    Accurate dielectronic recombination (DR) data are important for cosmic and laboratory plasma modeling. Over the past few years, our group has computed reliable DR data for all isoelectronic sequences up through Mg-like ions. Recently, we have focused our work on the complex third-row M-shell isoelectronic sequences, especially Al-like. Previous calculations for the DR rate coefficient for S^3+ were performed only within a non-relativistic LS-coupling approximation. Fe^13+ DR calculations, including semi-relativistic effects, have been completed and tested against the Heidelberg heavy-ion Test Storage Ring facility measurements. Here we present semi-relativistic DR rate coefficient calculations for a wide range of Al-like ions using AUTOSTRUCTURE, a level-resolved distorted-wave program package. The important effect of fine structure splitting in the Al-like ground state will be discussed. Finally, our results are fitted into a simple formula for use by astrophysical plasma modelers.This work was funded in part by NASA (APRA), NASA (SHP) SR&T, and UK PPARC grants.

  11. Diet and dietetics in al-Andalus.

    PubMed

    Salas-Salvadó, Jordi; Huetos-Solano, Maria D; García-Lorda, Pilar; Bulló, Mònica

    2006-08-01

    Al-Andalus society (711-1492) based its idea of health on the wisdom of Classical Greece, the Hippocratic-Galenic theories, as well as the Persian and Hindu cultures. The twelfth century in al-Andalus is considered to be the most prolific period for works of a scientific and technical nature. At the time, the main treatises on dietetics were written and this science reached its widest expression with such leading figures as Ibn Wāfīd, Avenzoar, Averroes and Maimonides, whose works revealed the first scientific knowledge on the nutritional processes of the human body. Diet was regarded as being essential for health and the prevention of disease. Dietary guidelines were written for different age groups, different body types and different seasons of the year. The amount of food to be ingested, the number of meals recommended and the order in which the food should be consumed were all issues that were discussed. A variety of foods were thought to have medicinal properties, some of which are known today. The diet in al-Andalus was varied and very probably made a substantial contribution to the origin of the present-day Mediterranean diet, rich in olive oil, wholemeal cereals, fruit and vegetables, fish, lamb, poultry, nuts and spices. We also find that many of the terms in current use in diet and agriculture are a living testimony to the Arabic influence, as are many of the dishes of our varied Mediterranean gastronomy.

  12. KCAT, Xradia, ALS and APS Performance Summary

    SciTech Connect

    Waters, A; Martz, H; Brown, W

    2004-09-30

    At Lawrence Livermore National Laboratory (LLNL) particular emphasis is being placed on the nondestructive characterization (NDC) of components, subassemblies and assemblies of millimeter-size extent with micrometer-size features (mesoscale). These mesoscale objects include materials that vary widely in composition, density, geometry and embedded features. Characterizing these mesoscale objects is critical for corroborating the physics codes that underlie LLNL's Stockpile Stewardship mission. In this report we present results from our efforts to quantitatively characterize the performance of several x-ray systems in an effort to benchmark existing systems and to determine which systems may have the best potential for our mesoscale imaging needs. Several different x-ray digital radiography (DR) and computed tomography (CT) systems exist that may be applicable to our mesoscale object characterization requirements, including microfocus and synchrotron systems. The systems we have benchmarked include KCAT (LLNL developed) and Xradia {mu}XCT (Xradia, Inc., Concord, CA), both microfocus systems, and Beamline 1-ID at the Advance Photon Source (APS) and the Tomography Beamline at the Advanced Light Source (ALS), both synchrotron based systems. The ALS Tomography Beamline is a new installation, and the data presented and analyzed here is some of the first to be acquired at the facility. It is important to note that the ALS system had not yet been optimized at the time we acquired data. Results for each of these systems has been independently documented elsewhere. In this report we summarize and compare the characterization results for these systems.

  13. Microplastic flow in SIC/AL composites

    SciTech Connect

    Shi, N.; Arsenault, R.J.

    1995-12-31

    Experimentally it has been determined that if a composite containing a reinforcement which has a different (in general lower) thermal coefficient of expansion as compared to the matrix, then upon cooling from the processing or annealing temperature, plastic relaxation of the misfit strain will occur. Also, experimentally it has been shown that as the size of the reinforcement is increased, i.e., from small spheres to large spheres, there is a decrease in the summation of the effective plastic strain in the matrix. In other words there is a decrease in the average dislocation density in the matrix. However, if the shape of the reinforcement is changed from spherical to short fiber to continuous filament, then the dislocation density increases. This experimental data is obtained at a constant volume fraction. A very simple model of plastic relaxation based on prismatic punching of dislocations from the interface can account for the decrease in the dislocation density with an increase reinforcement size, and the increase in dislocation density when changing the shape from a sphere to a continuous filament. A FEM analysis of the shape factor is also capable of predicting the correct trend. However, at present the continuum mechanics methods that have been investigated can not predict the size dependence. A simple model to explain the size effect in Al{sub 2}O{sub 3}/NiAl composites based on the deformation characteristics of NiAl will be discussed.

  14. Lower motor neuron dysfunction in ALS.

    PubMed

    de Carvalho, Mamede; Swash, Michael

    2016-07-01

    In the motor system there is a complex interplay between cortical structures and spinal cord lower motor neurons (LMN). In this system both inhibitory and excitatory neurons have relevant roles. LMN loss is a marker of motor neuron disease/amyotrophic lateral sclerosis (MND/ALS). Conventional needle electromyography (EMG) does not allow LMN loss to be quantified. Measurement of compound muscle action potential (CMAP) amplitude or area, and the neurophysiological index, provide a surrogate estimate of the number of functional motor units. Increased motor neuronal excitability is a neurophysiological marker of ALS in the context of a suspected clinical and electrophysiological diagnosis. In the LMN system, fasciculation potentials (FPs) are the earliest changes observed in affected muscles, a feature of LMN hyperexcitability. Reinnervation is best investigated by needle EMG although other methods can be explored. Moreover needle EMG give information about the temporal profile of the reinnervation process, important ancillary data. Quantitative motor unit potential analysis is a valuable method of evaluating reinnervation. The importance of FPs has been recognized in the Awaji criteria for the electrodiagnosis of ALS, criteria that are a sensitive adjunct to the revised El Escorial criteria. Finally, functionality of LMN's, and perhaps excitability studies in motor nerves, aids understanding of the disease process, allowing measurement of potential treatment effects in clinical trials. Other investigational techniques, such as electrical impedance myography, muscle and nerve ultrasound, and spinal cord imaging methods may prove useful in future. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  15. AlN antiresonant layer ARROW waveguides

    NASA Astrophysics Data System (ADS)

    Pelegrini, M. V.; Carvalho, D. O.; Alayo, M. I.; Pereyra, I.

    2010-02-01

    Aluminum Nitride (AlN) is a wide band gap III-V semiconductor material often used for optical applications due to its transparency and high refractive index. We have produced and characterized AlN thin films by reactive r.f. magnetron sputtering in different Ar-N2 atmospheres in order to verify the best gaseous concentration to be utilized as anti-resonant layer in ARROW waveguides. The corresponding films were characterized by Fourier transform infrared spectroscopy (FTIR), Rutherford backscattering spectroscopy (RBS), Ellipsometry and visible optical absorption. The AlN properties did not varied significantly between the films deposited with 20 and 70 sccm of N2, most of the variations occurred for films deposited with 18 sccm of N2 or below. The film deposited with 20 sccm was selected to be used as the first ARROW layer in the fabricated waveguides. Two routines were used to design the waveguides parameters, the transfer matrix method (TMM) and the semi-vectorial non-uniform finite difference method (NU-FDM). Attenuation as low as 3.5dB/cm was obtained for a 7 μm wide waveguide.

  16. An ALS (Advanced Light Source) handbook

    SciTech Connect

    Not Available

    1988-11-01

    This booklet aims to provide the prospective user of the Advanced Light Source with a concise description of the radiation a researcher might expect at his or her experimental station. The focus is therefore on the characteristics of the light that emerges from insertion devices and bending magnets and on how components of the beam lines further alter the properties of the radiation. The specifications and operating parameters of the ALS injection system and storage ring are of only peripheral interest. To this end, Sections 3 and 5 and most of Section 4 are devoted to summary presentations, by means of performance plots and tabular compilations, of radiation characteristics at the ALS--spectral brightness, flux, coherent power, resolution, time structure, etc.--assuming a representative set of four undulators and one wiggler and a corresponding set of five beam lines. As a complement to these performance summaries, Section 1 is a general introductory discussion of synchrotron radiation and the ALS, and Section 2 provides a compendious introduction to the characteristics of synchrotron radiation from bending magnets, wigglers, and undulators. In addition, Section 4 briefly introduces the theory of diffraction grating and crystal monochromators. 15 refs., 28 figs., 5 tabs.

  17. Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

    PubMed Central

    Abedini, Alam; Saion, Elias; Larki, Farhad; Zakaria, Azmi; Noroozi, Monir; Soltani, Nayereh

    2012-01-01

    Colloidal Cu@CuAlO2-Al2O3 bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a 60Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO2-Al2O3 nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO2-Al2O3 nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation. PMID:23109893

  18. Softening Kinetics in High Al and High Al-Nb-Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Pereda, B.; Aretxabaleta, Z.; López, B.

    2015-03-01

    Double-hit torsion tests were performed in order to study the effect of high Al levels (up to 2 wt.%) and Nb microalloying (up to 0.07 wt.%) on the static softening kinetics of 0.2%C-2%Mn steels. The addition of 1%Al leads to a delay in the softening kinetics due to solute-drag effect, equivalent to that exerted by 0.027%Nb. For the 2%Al steels, at temperatures below 1000 °C, γ → α phase transformation occurs after deformation, resulting in a larger retardation of the softening kinetics. At temperatures higher than 1000 °C, Nb in solid solution also contributes to the retardation of the static softening kinetics, and at lower temperatures NbC strain-induced precipitation leads to incomplete softening for the 1%Al steel, and to a complex interaction between softening, phase transformation, and NbC strain-induced precipitation for the 2%Al-Nb steels. The effect of Al on the static softening kinetics was quantified and introduced in a model developed in previous works for the prediction of the austenite microstructural evolution. In order to validate the results of the model, multipass torsion tests were carried out at conditions representative of hot strip and plate rolling mills. Model predictions show reasonable agreement with the results obtained at different deformation conditions.

  19. Internal photoemission in Ag-Al2O3-Al junctions

    NASA Technical Reports Server (NTRS)

    Guedes, J. M. P.; Slayman, C. W.; Gustafson, T. K.; Jain, R. K.

    1979-01-01

    The magnitude of the photon-induced current in Ag-Al2O3-Al metal-oxide-metal junctions has been studied as a function of photon energy and angle of incident radiation. Photocurrents were theoretically analyzed on the basis of a modified vacuum photoemission model (Jain, 1975; Slayman et al., to be published). Optical constants previously reported in the literature (Irani et al., 1971; Ehnrereich et al., 1963) were used to calculate the true spatial generation rate in Ag and Al as a function of the angle, polarization of incident radiation, and film thickness. Results were found to be in very good agreement with experimentally determined values for a tunable dye laser with a KDP doubling crystal pumped by a Q-switched Nd:YAG laser with a LiIO3 doubling crystal. The system provided risetimes of 50 ns or less and peak powers of 10 W. Under short circuit conditions, the photoresponse to incident power was linear up to available power densities of 10 kW/sq cm. Quantum efficiencies of about 0.1% at zero-bias, near 3.8 eV under P polarization, were typically observed.

  20. Redistribution of Ti and Al in deuterium charged TiAl

    NASA Technical Reports Server (NTRS)

    Legzdina, D.; Robertson, I. M.; Birnbaum, H. K.

    1992-01-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration.

  1. Redistribution of Ti and Al in deuterium charged TiAl

    NASA Technical Reports Server (NTRS)

    Legzdina, D.; Robertson, I. M.; Birnbaum, H. K.

    1992-01-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration.

  2. A comparative wear study on Al-Li and Al-Li/SiC composite

    SciTech Connect

    Okumus, S. Cem Karslioglu, Ramazan Akbulut, Hatem

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup −1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  3. Evaluation of aerial microbial pollutants in Al-Haram Al-Nabawi during pilgrimage of 2013.

    PubMed

    Alananbeh, Kholoud M; Boquellah, Nahla; Kaff, Nadia Al; Ahmadi, Majid Al

    2017-01-01

    Al-Madinah Al-Munawwarah is the second holiest site in Islam. The possibility of new emerging microbes is valid due to the increased number of pilgrims. The objectives of the current study were to estimate the numbers of fungi and bacteria inside and outside Al-Haram Al-Nabawi and to find whether new bacterial and fungal species have emerged compared to previous studies. Air samples were collected twice a day from 12 spots and four directions during the pilgrim year of 2013 for four consecutive weeks by using the sedimentation method. Thirty five genera and fifty eight species were identified. The most recovered bacterial genera were Staphylococcus, Micrococcus, Bacillus, and Dermacoccus with 32.47%, 18.18%, 12.85%, and 11.23%, respectively. Fifty nine isolates of fungi were molecularly identified. Aspergillus species had the highest percentage (78%). The other fungal genera identified (Alternaria triticina, Emericella nidulans, Emericella striata, Mucor circinelloides, Penicillium chrysogenum, Penicillium minioluteum, Rhizopus arrhizus, Rhizopus oryzae, and Syncephalastrum racemosum) had less than 5% frequency. In places such as Al-Haram Al-Nabawi, a large and crowded public (millions) exist especially during pilgrimages and Ramadan, thus, exposure to microorganisms is high. On the other hand, microorganism infectivity depends on many factors including their virulence, landing site, and person's immunity. For those reasons, many aspects should be considered to avoid aerosol contaminants.

  4. Dopant-Free GaN/AlN/AlGaN Radial Nanowire Heterostructures as High Electron Mobility Transistors

    DTIC Science & Technology

    2016-06-07

    microscopy (TEM) studies reveal that the GaN/ AlN/AlGaN radial nanowire heterostructures are dislocation -free single crystals. In addition, the...due to a reduction or elimination of impurity scattering by separating the dopants and surface potential fluctuations from the conduction channel . We...AlN/AlGaN radial nanowire heterostructures are dislocation -free single crystals. In addition, the thicknesses and compositions of the individual AlN

  5. Unveiling the Semicoherent Interface with Definite Orientation Relationships between Reinforcements and Matrix in Novel Al3BC/Al Composites.

    PubMed

    Zhao, Yongfeng; Qian, Zhao; Ma, Xia; Chen, Houwen; Gao, Tong; Wu, Yuying; Liu, Xiangfa

    2016-10-05

    High-strength lightweight Al-based composites are promising materials for a wide range of applications. To provide high performance, a strong bonding interface for effective load transfer from the matrix to the reinforcement is essential. In this work, the novel Al3BC reinforced Al composites have been in situ fabricated through a liquid-solid reaction method and the bonding interface between Al3BC and Al matrix has been unveiled. The HRTEM characterizations on the Al3BC/Al interface verify it to be a semicoherent bonding structure with definite orientation relationships: (0001)Al3BC//(11̅1)Al;[112̅0]Al3BC//[011]Al. Periodic arrays of geometrical misfit dislocations are also observed along the interface at each (0001)Al3BC plane or every five (11̅1)Al planes. This kind of interface between the reinforcement and the matrix is strong enough for effective load transfer, which would lead to the evidently improved strength and stiffness of the introduced new Al3BC/Al composites.

  6. Electrical stress effect on Josephson tunneling through ultrathin AlOx barrier in Nb/Al/AlOx/Nb junctions

    NASA Astrophysics Data System (ADS)

    Tolpygo, Sergey K.; Amparo, Denis

    2008-09-01

    The effect of dc electrical stress and breakdown on Josephson and quasiparticle tunneling in Nb/Al/AlOx/Nb junctions with ultrathin AlOx barriers typical for applications in superconductor digital electronics has been investigated. The junctions' conductance at room temperature and current-voltage (I-V) characteristics at 4.2 K have been measured after the consecutive stressing of the tunnel barrier at room temperature. Electrical stress was applied using current ramps with increasing amplitude ranging from 0 to ˜1000Ic corresponding to voltages across the barrier up to ˜0.65 V, where Ic is the Josephson critical current. A very soft breakdown has been observed with polarity-dependent breakdown current (voltage). As the stressing progresses, a dramatic increase in subgap conductance of the junctions, the appearance of subharmonic current steps, and a gradual increase in both the critical and the excess currents as well as a decrease in the normal-state resistance have been observed. The observed changes in superconducting tunneling suggest a model in which a progressively increasing number of defects and associated additional conduction channels [superconducting quantum point contacts (SQPCs)] are induced by electric field in the tunnel barrier. By comparing the I-V characteristics of these conduction channels with the nonstationary theory of current transport in SQPCs based on multiple Andreev reflections by Averin and Bardas, the typical transparency D of the induced SQPCs was estimated as D ˜0.7. The number of induced SQPCs was found to grow with voltage across the barrier as sinh(V /V0) with V0=0.045 V, in good agreement with the proposed model of defect formation by ion electromigration. The observed polarity dependence of the breakdown current (voltage) is also consistent with the model. Based on the observed magnitude of breakdown currents, electric breakdown of AlOx barrier during plasma processing was considered to be an unlikely cause of fabrication

  7. The oxidation of Ni-rich Ni-Al intermetallics

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph; Smialek, James L.; Barrett, Charles A.

    1988-01-01

    The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al2O3 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.

  8. Creep and Toughness of Cryomilled NiAl Containing Cr

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Aikin, Beverly; Salem, Jon

    2000-01-01

    NiAl-AlN + Cr composites were produced by blending cryomilled NiAl powder with approx. 10 vol % Cr flakes. In comparison to the as-consolidated matrices, hot isostatically pressed Cr-modified materials did not demonstrate any significant improvement in toughness. Hot extruded NiAl-AlN+10.5Cr, however, possessed a toughness twice that determine for the base NiAl-AlN alloy. Measurement of the 1200 to 1400 K plastic flow properties revealed that the strength of the composites was completely controlled by the properties of the NiAl-AlN matrices. This behavior could be successfully modeled by the Rule-of-Mixtures, where load is shed from the weak Cr to the strong matrix.

  9. Unexpected Stability of Al4H6: a Borane Analog?

    NASA Astrophysics Data System (ADS)

    Xi, Li; Grubisic, Andrej; Stokes, Sarah; Gantefor, Gerd; Bowen, Kit; Boggavarapu, Kiran; Willis, Mary; Jena, Puru; Burgert, Ralph; Schnockel, Hans; Cordes, James

    2007-03-01

    While boron has many hydrides, aluminum has been thought to exhibit relatively few. A combined anion photoelectron and density functional theory computational study of the Al4H6^- anion, and its corresponding neutral, Al4H6, showed that Al4H6 can be understood in terms of the Wade-Mingos rules for electron counting, suggesting that it may be a borane analog. The data support an Al4H6 structure with a distorted tetrahedral aluminum atom framework, four terminal Al-H bonds, and two sets of counter-positioned Al-H-Al bridging bonds. The large HOMO-LUMO gap found for Al4H6 together with its exceptionally high heat of combustion further suggests that Al4H6 may be an important energetic material, if it can be prepared in bulk. This report announces the opening of a new chapter in aluminum-hydrogen chemistry.

  10. Reactive plasma spraying of Al-Ti alloys

    SciTech Connect

    Entezarian, M.; Shanker, K.; Tsantrizos, P.G.; Allaire, F.; Immarigeon, J.P.; Drew, R.A.L.

    1995-12-31

    Reactive plasma spraying was used to synthesize Al alloys containing a dispersion of TiAl{sub 3} intermetallics. Either Al powder or Al wire and TiCl{sub 4} were the raw materials used. The size, distribution, and morphology of the intermetallic phase were a function of the injection manner of the starting materials, the plasma process parameters, and the molar ratio of the reactants (TiCl{sub 4}/Al). Under optimum conditions, a fine dispersion of micron sized intermetallics was obtained. Investigation of the reaction mechanism showed that the particle`s temperature was a critical factor in producing a fine dispersion of TiAl{sub 3} phase in an Al matrix. Materials produced at temperatures below the melting point of TiAl{sub 3} resulted in a microstructure containing an Al core with a TiAl{sub 3} shell. In contrast, materials produced at higher temperatures resulted in a fine TiAl{sub 3} phase precipitating from the Al-Ti melt during the solidification process. Products were collected as porous deposited layers whose surface was contaminated with chlorides. The products were subjected to purification followed by hot rolling for further consolidation. The effectiveness of vacuum thermal treatment on the removal of Cl was investigated. Al chlorides could be removed by thermal treatments at temperatures below the melting point of Al, while some of the Ti subchlorides required higher temperatures. The mechanical properties of the consolidated materials were also determined and are reported.

  11. The Nature of Interfaces in Al-1050/Al-1050 and Al-1050/Mg-AZ31 Couples Joined by Magnetic Pulse Welding (MPW)

    NASA Astrophysics Data System (ADS)

    Stern, A.; Aizenshtein, M.; Moshe, G.; Cohen, S. R.; Frage, N.

    2013-07-01

    The microstructure and the phase composition of the interfaces of Al-1050/Al-1050 and Al-1050/Mg-AZ31 magnetic pulse welding (MPW) joints were characterized by SEM and TEM analyses. The mechanical properties were tested by nanoindentation. Properties of the Al-1050/Al-1050 interface joint were established. The interface is almost free from Al3Fe precipitates, which are present in the base metal. The hardness value is higher than that of the base metal; however, values of the Young's modulus of the interface and base metal are similar. It was suggested that the interface evolution in the Al-1050/Al-1050 system includes local melting and rapid solidification of the base materials. A wavy shaped heterogeneous interface was detected in the Al-1050/Mg-AZ31 joints. Some areas are free from visible intermetallic phases (IMPs), while others contain pockets of relatively coarse intermetallic precipitates. The presence of a relatively large fraction of globular porosity at the interface indicates that local melting takes place in the course of MPW. TEM characterization of regions free of IMPs at the interface reveals regions consisting of fcc supersaturated Al-Mg solid solution, apparently formed as a result of local mechanical alloying during MPW. In other regions, the composition and structure correspond to the Mg17Al12 phase, which was probably formed by local melting and rapid solidification.

  12. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

    NASA Astrophysics Data System (ADS)

    Xu, Yuan; Chang, Benkang; Chen, Xinlong; Qian, Yunsheng

    2017-08-01

    We designed two transmission-mode GaAs/AlGaAs photocathodes with different Al x Ga1-x As layers, one has an Al x Ga1-x As layer with the Al component ranging from 0.9 to 0, and the other has a fixed Al component 0.7. Using the first-principle method, we calculated the electronic structure and absorption spectrum of Al x Ga1-x As at x = 0, 0.25, 0.5, 0.75 and 1, calculation results suggest that with the increase of the Al component, the band gap of Al x Ga1-x As increases. Then we activated the two samples, and obtained the spectral response curves and quantum efficiency curves; it is found that sample 1 has a better shortwave response and higher quantum efficiency at short wavelengths. Combined with the band structure diagram of the transmission-mode GaAs/AlGaAs photocathode and the fitted performance parameters, we analyze the phenomenon. It is found that the transmission-mode GaAs/AlGaAs photocathode with variable Al component and various doping structure can form a two-stage built-in electric field, which improves the probability of shortwave response photoelectrons escaping to the vacuum. In conclusion, such a structure reduces the influence of back-interface recombination, improves the shortwave response of the transmission-mode photocathode. Project supported by the National Natural Science Foundation of China (Nos. 91433108, 61301023).

  13. Effect of nitrogen incorporation into Al-based gate insulators in AlON/AlGaN/GaN metal-oxide-semiconductor structures

    NASA Astrophysics Data System (ADS)

    Asahara, Ryohei; Nozaki, Mikito; Yamada, Takahiro; Ito, Joyo; Nakazawa, Satoshi; Ishida, Masahiro; Ueda, Tetsuzo; Yoshigoe, Akitaka; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2016-10-01

    The superior physical and electrical properties of aluminum oxynitride (AlON) gate dielectrics on AlGaN/GaN substrates in terms of thermal stability, reliability, and interface quality were demonstrated by direct AlON deposition and subsequent annealing. Nitrogen incorporation into alumina was proven to be beneficial both for suppressing intermixing at the insulator/AlGaN interface and reducing the number of electrical defects in Al2O3 films. Consequently, we achieved high-quality AlON/AlGaN/GaN metal-oxide-semiconductor capacitors with improved stability against charge injection and a reduced interface state density as low as 1.2 × 1011 cm-2 eV-1. The impact of nitrogen incorporation into the insulator will be discussed on the basis of experimental findings.

  14. Chemical ordering and large tunnel magnetoresistance in Co2FeAl/MgAl2O4/Co2FeAl(001) junctions

    NASA Astrophysics Data System (ADS)

    Scheike, Thomas; Sukegawa, Hiroaki; Inomata, Koichiro; Ohkubo, Tadakatsu; Hono, Kazuhiro; Mitani, Seiji

    2016-05-01

    Epitaxial magnetic tunnel junctions (MTJs) with a Co2FeAl/CoFe (0.5 nm)/MgAl2O4/Co2FeAl(001) structure were fabricated by magnetron sputtering. High-temperature in situ annealing led to a high degree of B2-order in the Co2FeAl layers and cation order of the MgAl2O4 barrier. Large tunnel magnetoresistance (TMR) of up to 342% was obtained at room temperature (616% at 4 K), in contrast to the TMR ratio ( ≲ 160%) suppressed by the band-folding effect in Fe/cation-ordered MgAl2O4/Fe MTJs. The present study reveals that the high degree of B2-order and the resulting high spin polarization in the Co2FeAl electrodes enable us to bypass the band-folding problem in spinel barriers.

  15. Al-Ca and Al-Fe metal-metal composite strength, conductivity, and microstructure relationships

    SciTech Connect

    Kim, Hyong June

    2011-01-01

    Deformation processed metal-metal composites (DMMC’s) are composites formed by mechanical working (i.e., rolling, swaging, or wire drawing) of two-phase, ductile metal mixtures. Since both the matrix and reinforcing phase are ductile metals, the composites can be heavily deformed to reduce the thickness and spacing of the two phases. Recent studies have shown that heavily drawn DMMCs can achieve anomalously high strength and outstanding combinations of strength and conductivity. In this study, Al-Fe wire composite with 0.07, 0.1, and 0.2 volume fractions of Fe filaments and Al-Ca wire composite with 0.03, 0.06, and 0.09 volume fractions of Ca filaments were produced in situ, and their mechanical properties were measured as a function of deformation true strain. The Al-Fe composites displayed limited deformation of the Fe phase even at high true strains, resulting in little strengthening effect in those composites. Al-9vol%Ca wire was deformed to a deformation true strain of 13.76. The resulting Ca second-phase filaments were deformed to thicknesses on the order of one micrometer. The ultimate tensile strength increased exponentially with increasing deformation true strain, reaching a value of 197 MPa at a true strain of 13.76. This value is 2.5 times higher than the value predicted by the rule of mixtures. A quantitative relationship between UTS and deformation true strain was determined. X-ray diffraction data on transformation of Al + Ca microstructures to Al + various Al-Ca intermetallic compounds were obtained at the Advanced Photon Source at Argonne National Laboratory. Electrical conductivity was measured over a range of true strains and post-deformation heat treatment schedules.

  16. Transcriptome Analysis of Al-Induced Genes in Buckwheat (Fagopyrum esculentum Moench) Root Apex: New Insight into Al Toxicity and Resistance Mechanisms in an Al Accumulating Species.

    PubMed

    Xu, Jia Meng; Fan, Wei; Jin, Jian Feng; Lou, He Qiang; Chen, Wei Wei; Yang, Jian Li; Zheng, Shao Jian

    2017-01-01

    Relying on Al-activated root oxalate secretion, and internal detoxification and accumulation of Al, buckwheat is highly Al resistant. However, the molecular mechanisms responsible for these processes are still poorly understood. It is well-known that root apex is the critical region of Al toxicity that rapidly impairs a series of events, thus, resulting in inhibition of root elongation. Here, we carried out transcriptome analysis of the buckwheat root apex (0-1 cm) with regards to early response (first 6 h) to Al stress (20 μM), which is crucial for identification of both genes and processes involved in Al toxicity and tolerance mechanisms. We obtained 34,469 unigenes with 26,664 unigenes annotated in the NCBI database, and identified 589 up-regulated and 255 down-regulated differentially expressed genes (DEGs) under Al stress. Functional category analysis revealed that biological processes differ between up- and down-regulated genes, although 'metabolic processes' were the most affected category in both up- and down-regulated DEGs. Based on the data, it is proposed that Al stress affects a variety of biological processes that collectively contributes to the inhibition of root elongation. We identified 30 transporter genes and 27 transcription factor (TF) genes induced by Al. Gene homology analysis highlighted candidate genes encoding transporters associated with Al uptake, transport, detoxification, and accumulation. We also found that TFs play critical role in transcriptional regulation of Al resistance genes in buckwheat. In addition, gene duplication events are very common in the buckwheat genome, suggesting a possible role for gene duplication in the species' high Al resistance. Taken together, the transcriptomic analysis of buckwheat root apex shed light on the processes that contribute to the inhibition of root elongation. Furthermore, the comprehensive analysis of both transporter genes and TF genes not only deep our understanding on the responses of

  17. Covalent bonds in AlMnSi icosahedral quasicrystalline approximant

    PubMed

    Kirihara; Nakata; Takata; Kubota; Nishibori; Kimura; Sakata

    2000-10-16

    Electron density distributions were obtained using the maximum entropy method with synchrotron radiation powder data. In the metallic Al12Re, metallic bonding was observed for the icosahedral Al12 cluster with central Re atom. In the nonmetallic alpha-AlMnSi 1/1 approximant, covalent bonds were found in the electron density distribution of the Mackay icosahedral cluster without central atom. Rather than the Hume-Rothery mechanism, the covalency of Al (Si) icosahedron and that between Al (Si) and Mn atoms is considered to be the origin of the pseudogap and nonmetallic behavior of alpha-AlMnSi.

  18. Interfacial microstructure and growth mechanism of Al4C3 in Grf/Al composites fabricated by liquid pressure method.

    PubMed

    Xu, Wang; Chenchong, Wang; Zhichao, Zhang; Ping, Liang; Yanhua, Shi; Guofu, Zhang

    2014-10-01

    In this study, Grf/Al composite was fabricated by liquid pressure method. The diffusion layer and the nucleation and growth of Al4C3 were observed at the interface of Grf/Al composites by TEM and HRTEM. The growth mechanism of Al4C3 was analyzed in detail by crystallography theory. It was found that Al4C3 had no phase relations with the carbon fiber. (0001) layer of Al4C3 was parallel with main growth direction. Both the diffusion layer at the interface and crystal structure of Al4C3 affected the shape of Al4C3. At a certain position, Al4C3 could connect two fibers when the fibers were close to each other. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Millimeter distance effects of surface plasmon polaritons in electroformed Al-Al2O3-Ag diodes

    NASA Astrophysics Data System (ADS)

    Hickmott, T. W.

    2017-02-01

    Electroforming of metal-insulator-metal diodes is a soft dielectric breakdown that changes the high resistance of as-prepared diodes to a low resistance state. Electroforming of Al-Al2O3-metal diodes with anodic Al2O3 results in voltage-controlled negative resistance in the current-voltage (I-V) characteristics, electroluminescence (EL), and electron emission into vacuum (EM). EL is due to electrons injected at the Al-Al2O3 interface combining with radiative defects in Al2O3. Surface plasmon polaritons (SPPs) are electromagnetic waves that can be excited by photons or electrons. SPPs are confined to a metal-dielectric interface, cause large electric fields in the metal and dielectric, and have ranges of micrometers. The temperature dependence of I-V curves, EL, and EM of a group of electroformed Al-Al2O3-Ag diodes with Al2O3 thicknesses between 12 nm and 20 nm, group A, was measured between 200 K and 300 K. After a sequence of temperature measurements, the Al-Al2O3-Ag diodes, the Al-Al2O3 regions between diodes, and portions of the Ag on the glass region that provides contacts to the diodes are darkened. The range of darkening is >7 mm in a diode with 12 nm of Al2O3 and 2.0-3.5 mm in diodes with Al2O3 thicknesses between 14 nm and 20 nm. Darkening is attributed to the occurrence of SPPs generated by EL photons at the Ag-Al2O3 and Al-Al2O3 interfaces. The results are compared to a second group of Al-Al2O3-Ag diodes with identical Al2O3 thicknesses, group B, that were prepared in the same way as the diodes of group A except for a difference in the deposition of Al films for the two groups. Al-Al2O3-Ag diodes of group B exhibit enhanced EL, which is attributed to spontaneous emission of recombination centers in Al2O3 being enhanced by large electromagnetic fields that are due to SPPs that are generated by EL photons.

  20. Processing and characterization of Al-Al3Nb prepared by mechanical alloying and equal channel angular pressing

    NASA Astrophysics Data System (ADS)

    Chandran, P.; Zafari, A.; Lui, E. W.; Xia, K.

    2017-05-01

    Mechanically alloyed Al with immiscible elements such as Nb can lead to a uniform distribution of nanoscaled precipitates which are highly stable compared to conventional alloying and with excellent interface, resulting in significant increase in strength without problems associated with nano ceramic particles in metal matrix composites. Although immiscible, Nb can be alloyed with Al through mechanical milling, forming trialuminide (Al3Nb), either directly or upon subsequent precipitation, which possesses high strength, stiffness and stability at elevated temperatures. In the present study, Al-5 at.% Nb supersaturated solid solution was achieved after prolonged ball milling and nano Al3Nb precipitates were formed during subsequent ageing at 530°C. The Al-Al3Nb powder was consolidated by equal channel angular pressing (ECAP) at 400°C, resulting in a fully dense material with a uniform distribution of nanoscaled Al3Nb precipitates in the Al matrix.