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Sample records for asymmetric post-natal development

  1. Morphology of non-sensory epithelium during post-natal development of the rabbit vomeronasal organ.

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    Elgayar, S A M; Eltony, S A; Othman, M A

    2014-08-01

    The vomeronasal organ (VNO), because of its ability to detect pheromones, has an important role in many social and sexual behaviours in mammals. It also mediates defensive behaviours through detection of protein pheromone homologues. A detailed morphological description of the post-natal development of the 'non-sensory' epithelium (NSE) of the female rabbit is recorded. Histological techniques were used to study the NSE of the VNO in post-natal development of female rabbits. The study focused on the following post-natal ages: newborn, 1 week, 2 weeks and 1 month (five animals each) beside to two adult animals. The rabbit VNO was surrounded externally by bony capsule and internally by cartilaginous capsule. NSE was pseudostratified columnar partially ciliated epithelium without goblet cells. In addition to basal cells, NSE contained ciliated and three types of non-ciliated columnar cells (dark, pale and light). At birth, dark cells may have primary cilia. By 1 month, the cytoplasm became lighter with less free ribosomes. The pale cells had electron-lucent cytoplasm, which contained a few organelles. Mitotic figures were observed in basal and columnar cells, particularly during the first 2 weeks of post-natal development. Light columnar cells were common during the first week. Numerous leucocytes and a few nerve endings were detected intra-epithelial. Scanning electron microscope revealed a gradual increase in height of microvilli of non-ciliated cells. Ciliated cells had cilia and microvilli. Cells were arranged singly, in clumps or in a dense population of cells. The rabbit VNO-NSE had a unique morphological structure. PMID:23931650

  2. Characterisation of microRNA expression in post-natal mouse mammary gland development

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    Karagavriilidou Konstantina

    2009-11-01

    Full Text Available Abstract Background The differential expression pattern of microRNAs (miRNAs during mammary gland development might provide insights into their role in regulating the homeostasis of the mammary epithelium. Our aim was to analyse these regulatory functions by deriving a comprehensive tissue-specific combined miRNA and mRNA expression profile of post-natal mouse mammary gland development. We measured the expression of 318 individual murine miRNAs by bead-based flow-cytometric profiling of whole mouse mammary glands throughout a 16-point developmental time course, including juvenile, puberty, mature virgin, gestation, lactation, and involution stages. In parallel whole-genome mRNA expression data were obtained. Results One third (n = 102 of all murine miRNAs analysed were detected during mammary gland development. MicroRNAs were represented in seven temporally co-expressed clusters, which were enriched for both miRNAs belonging to the same family and breast cancer-associated miRNAs. Global miRNA and mRNA expression was significantly reduced during lactation and the early stages of involution after weaning. For most detected miRNA families we did not observe systematic changes in the expression of predicted targets. For miRNA families whose targets did show changes, we observed inverse patterns of miRNA and target expression. The data sets are made publicly available and the combined expression profiles represent an important community resource for mammary gland biology research. Conclusion MicroRNAs were expressed in likely co-regulated clusters during mammary gland development. Breast cancer-associated miRNAs were significantly enriched in these clusters. The mechanism and functional consequences of this miRNA co-regulation provide new avenues for research into mammary gland biology and generate candidates for functional validation.

  3. Indian hedgehog roles in post-natal TMJ development and organization.

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    Ochiai, T; Shibukawa, Y; Nagayama, M; Mundy, C; Yasuda, T; Okabe, T; Shimono, K; Kanyama, M; Hasegawa, H; Maeda, Y; Lanske, B; Pacifici, M; Koyama, E

    2010-04-01

    Indian hedgehog (Ihh) is essential for embryonic mandibular condylar growth and disc primordium formation. To determine whether it regulates those processes during post-natal life, we ablated Ihh in cartilage of neonatal mice and assessed the consequences on temporomandibular joint (TMJ) growth and organization over age. Ihh deficiency caused condylar disorganization and growth retardation and reduced polymorphic cell layer proliferation. Expression of Sox9, Runx2, and Osterix was low, as was that of collagen II, collagen I, and aggrecan, thus altering the fibrocartilaginous nature of the condyle. Though a disc formed, it exhibited morphological defects, partial fusion with the glenoid bone surface, reduced synovial cavity space, and, unexpectedly, higher lubricin expression. Analysis of the data shows, for the first time, that continuous Ihh action is required for completion of post-natal TMJ growth and organization. Lubricin overexpression in mutants may represent a compensatory response to sustain TMJ movement and function. PMID:20200412

  4. Unbiased cell quantification reveals a continued increase in the number of neocortical neurones during early post-natal development in mice

    DEFF Research Database (Denmark)

    Lyck, Lise; Krøigård, Thomas; Finsen, Bente

    2007-01-01

    the number of neurones and glia in the neocortex during post-natal development in two separate strains of mice. Cell counting by the optical fractionator revealed that the number of neurones increased 80-100% from the time of birth to post-natal day (P)16, followed by a reduction by approximately 25...... was delayed until P16. The number of glia reached its maximum at P16, whereas the number of oligodendroglia, identified using a transgenic marker, increased until P55, the latest time of observation. Neurones continued to accumulate in the developing neocortex during the first 2 weeks of post...

  5. Migration and Phagocytic Ability of Activated Microglia During Post-natal Development is Mediated by Calcium-Dependent Purinergic Signalling.

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    Sunkaria, Aditya; Bhardwaj, Supriya; Halder, Avishek; Yadav, Aarti; Sandhir, Rajat

    2016-03-01

    Microglia play an important role in synaptic pruning and controlled phagocytosis of neuronal cells during developmental stages. However, the mechanisms that regulate these functions are not completely understood. The present study was designed to investigate the role of purinergic signalling in microglial migration and phagocytic activity during post-natal brain development. One-day-old BALB/c mice received lipopolysaccharide (LPS) and/or a purinergic analogue (2-methylthioladenosine-5'-diphosphate; 2MeSADP), intracerebroventrically (i.c.v.). Combined administration of LPS and 2MeSADP resulted in activation of microglia as evident from increased expression of ionised calcium-binding adapter molecule 1 (Iba1). Activated microglia showed increased expression of purinergic receptors (P2Y2, P2Y6 and P2Y12). LPS either alone or in combination with 2MeSADP induced the expression of Na(+)/Ca(2+) exchanger (NCX-1) and P/Q-type Ca(2+) channels along with MARCKS-related protein (MRP), which is an integral component of cell migration machinery. In addition, LPS and 2MeSADP administration induced the expression of microglial CD11b and DAP12 (DNAX-activation protein 12), which are known to be involved in phagocytosis of neurons during development. Interestingly, administration of thapsigargin (TG), a specific Ca(2+)-ATPase inhibitor of endoplasmic reticulum, prevented the LPS/2MeSADP-induced microglial activation and migration by down-regulating the expression of Iba1 and MRP, respectively. Moreover, TG also reduced the LPS/2MeSADP-induced expression of CD11b/DAP12. Taken together, the findings reveal for the first time that Ca(2+)-mediated purinergic receptors regulate the migration and phagocytic ability of microglia during post-natal brain development. PMID:25575683

  6. Long-Term Supplementation with Beta Serum Concentrate (BSC, a Complex of Milk Lipids, during Post-Natal Brain Development Improves Memory in Rats

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    Jian Guan

    2015-06-01

    Full Text Available We have previously reported that the supplementation of ganglioside-enriched complex-milk-lipids improves cognitive function and that a phospholipid-enriched complex-milk-lipid prevents age-related cognitive decline in rats. This current study evaluated the effects of post-natal supplementation of ganglioside- and phospholipid-enriched complex-milk-lipids beta serum concentrate (BSC on cognitive function in young rats. The diet of male rats was supplemented with either gels formulated BSC (n = 16 or blank gels (n = 16 from post-natal day 10 to day 70. Memory and anxiety-like behaviors were evaluated using the Morris water maze, dark–light boxes, and elevated plus maze tests. Neuroplasticity and white matter were measured using immunohistochemical staining. The overall performance in seven-day acquisition trials was similar between the groups. Compared with the control group, BSC supplementation reduced the latency to the platform during day one of the acquisition tests. Supplementation improved memory by showing reduced latency and improved path efficiency to the platform quadrant, and smaller initial heading error from the platform zone. Supplemented rats showed an increase in striatal dopamine terminals and hippocampal glutamate receptors. Thus BSC supplementation during post-natal brain development improved learning and memory, independent from anxiety. The moderately enhanced neuroplasticity in dopamine and glutamate may be biological changes underlying the improved cognitive function.

  7. Long-Term Supplementation with Beta Serum Concentrate (BSC), a Complex of Milk Lipids, during Post-Natal Brain Development Improves Memory in Rats.

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    Guan, Jian; MacGibbon, Alastair; Fong, Bertram; Zhang, Rong; Liu, Karen; Rowan, Angela; McJarrow, Paul

    2015-06-05

    We have previously reported that the supplementation of ganglioside-enriched complex-milk-lipids improves cognitive function and that a phospholipid-enriched complex-milk-lipid prevents age-related cognitive decline in rats. This current study evaluated the effects of post-natal supplementation of ganglioside- and phospholipid-enriched complex-milk-lipids beta serum concentrate (BSC) on cognitive function in young rats. The diet of male rats was supplemented with either gels formulated BSC (n = 16) or blank gels (n = 16) from post-natal day 10 to day 70. Memory and anxiety-like behaviors were evaluated using the Morris water maze, dark-light boxes, and elevated plus maze tests. Neuroplasticity and white matter were measured using immunohistochemical staining. The overall performance in seven-day acquisition trials was similar between the groups. Compared with the control group, BSC supplementation reduced the latency to the platform during day one of the acquisition tests. Supplementation improved memory by showing reduced latency and improved path efficiency to the platform quadrant, and smaller initial heading error from the platform zone. Supplemented rats showed an increase in striatal dopamine terminals and hippocampal glutamate receptors. Thus BSC supplementation during post-natal brain development improved learning and memory, independent from anxiety. The moderately enhanced neuroplasticity in dopamine and glutamate may be biological changes underlying the improved cognitive function.

  8. Elk3 deficiency causes transient impairment in post-natal retinal vascular development and formation of tortuous arteries in adult murine retinae.

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    Weinl, Christine; Wasylyk, Christine; Garcia Garrido, Marina; Sothilingam, Vithiyanjali; Beck, Susanne C; Riehle, Heidemarie; Stritt, Christine; Roux, Michel J; Seeliger, Mathias W; Wasylyk, Bohdan; Nordheim, Alfred

    2014-01-01

    Serum Response Factor (SRF) fulfills essential roles in post-natal retinal angiogenesis and adult neovascularization. These functions have been attributed to the recruitment by SRF of the cofactors Myocardin-Related Transcription Factors MRTF-A and -B, but not the Ternary Complex Factors (TCFs) Elk1 and Elk4. The role of the third TCF, Elk3, remained unknown. We generated a new Elk3 knockout mouse line and showed that Elk3 had specific, non-redundant functions in the retinal vasculature. In Elk3(-/-) mice, post-natal retinal angiogenesis was transiently delayed until P8, after which it proceeded normally. Interestingly, tortuous arteries developed in Elk3(-/-) mice from the age of four weeks, and persisted into late adulthood. Tortuous vessels have been observed in human pathologies, e.g. in ROP and FEVR. These human disorders were linked to altered activities of vascular endothelial growth factor (VEGF) in the affected eyes. However, in Elk3(-/-) mice, we did not observe any changes in VEGF or several other potential confounding factors, including mural cell coverage and blood pressure. Instead, concurrent with the post-natal transient delay of radial outgrowth and the formation of adult tortuous arteries, Elk3-dependent effects on the expression of Angiopoietin/Tie-signalling components were observed. Moreover, in vitro microvessel sprouting and microtube formation from P10 and adult aortic ring explants were reduced. Collectively, these results indicate that Elk3 has distinct roles in maintaining retinal artery integrity. The Elk3 knockout mouse is presented as a new animal model to study retinal artery tortuousity in mice and human patients. PMID:25203538

  9. Elk3 deficiency causes transient impairment in post-natal retinal vascular development and formation of tortuous arteries in adult murine retinae.

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    Christine Weinl

    Full Text Available Serum Response Factor (SRF fulfills essential roles in post-natal retinal angiogenesis and adult neovascularization. These functions have been attributed to the recruitment by SRF of the cofactors Myocardin-Related Transcription Factors MRTF-A and -B, but not the Ternary Complex Factors (TCFs Elk1 and Elk4. The role of the third TCF, Elk3, remained unknown. We generated a new Elk3 knockout mouse line and showed that Elk3 had specific, non-redundant functions in the retinal vasculature. In Elk3(-/- mice, post-natal retinal angiogenesis was transiently delayed until P8, after which it proceeded normally. Interestingly, tortuous arteries developed in Elk3(-/- mice from the age of four weeks, and persisted into late adulthood. Tortuous vessels have been observed in human pathologies, e.g. in ROP and FEVR. These human disorders were linked to altered activities of vascular endothelial growth factor (VEGF in the affected eyes. However, in Elk3(-/- mice, we did not observe any changes in VEGF or several other potential confounding factors, including mural cell coverage and blood pressure. Instead, concurrent with the post-natal transient delay of radial outgrowth and the formation of adult tortuous arteries, Elk3-dependent effects on the expression of Angiopoietin/Tie-signalling components were observed. Moreover, in vitro microvessel sprouting and microtube formation from P10 and adult aortic ring explants were reduced. Collectively, these results indicate that Elk3 has distinct roles in maintaining retinal artery integrity. The Elk3 knockout mouse is presented as a new animal model to study retinal artery tortuousity in mice and human patients.

  10. First Evidence of DAAM1 Localization During the Post-Natal Development of Rat Testis and in Mammalian Sperm.

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    Pariante, Paolo; Dotolo, Raffaele; Venditti, Massimo; Ferrara, Diana; Donizetti, Aldo; Aniello, Francesco; Minucci, Sergio

    2016-10-01

    Dishevelled-associated activator of morphogenesis 1 (DAAM1) is a formin-family protein involved in nucleation of unbranched actin filaments and in cytoskeletal organization through Wnt-Dishevelled PCP pathway, which participates in essential biological processes, such as cell polarity, movement, and adhesion during morphogenesis and organogenesis. While its role has been investigated during development and in somatic cells, its potential association with the germinal compartment and reproduction is still unexplored. In this work, we assessed the possible association of DAAM1 with the morphogenesis of rat testis. We studied its expression and profiled its localization versus actin and tubulin, during the first wave of spermatogenesis and in the adult gonad (from 7 to 60 dpp). We show that, in mitotic phases, DAAM1 shares its localization with actin in Sertoli cells, gonocytes, and spermatogonia. Later, during meiosis, both proteins are found in spermatocytes, while only actin is detectable at the forming blood-testis barrier. DAAM1, then, follows the development of the acrosome system throughout spermiogenesis, and it is finally retained inside the cytoplasmic droplet in mature gametes, as corroborated by additional immunolocalization data on both rat and human sperm. Unlike the DAAM1, actin keeps its localization in Sertoli cells, and tubulin is associated with their protruding cytoplasm during the process. Our data support, for the first time, the hypothesis of a role for DAAM1 in cytoskeletal organization during Mammalian testis morphogenesis and gamete progression, while also hinting at its possible investigation as a morphological marker of germ cell and sperm physiology. J. Cell. Physiol. 231: 2172-2184, 2016. © 2016 Wiley Periodicals, Inc. PMID:26831620

  11. Effects of long-term pre- and post-natal exposure to 2.45 GHz wireless devices on developing male rat kidney.

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    Kuybulu, Ayça Esra; Öktem, Faruk; Çiriş, İbrahim Metin; Sutcu, Recep; Örmeci, Ahmet Rıfat; Çömlekçi, Selçuk; Uz, Efkan

    2016-05-01

    Purpose The aim of the present study was to investigate oxidative stress and apoptosis in kidney tissues of male Wistar rats that pre- and postnatally exposed to wireless electromagnetic field (EMF) with an internet frequency of 2.45 GHz for a long time. Methods The study was conducted in three groups of rats which were pre-natal, post-natal. and sham exposed groups. Oxidative stress markers and histological evaluation of kidney tissues were studied. Results Renal tissue malondialdehyde (MDA) and total oxidant (TOS) levels of pre-natal group were high and total antioxidant (TAS) and superoxide dismutase (SOD) levels were low. Spot urine NAG/creatinine ratio was significantly higher in pre- and post-natal groups (p Bcl-2 in cortical and medullar areas of pre-natal group (p values, 0.000, 0.002, 0.000, respectively) when compared with sham group. Bcl2/Bax staining intensity ratios of medullar and cortical area was higher in pre-natal group than sham group (p = 0.018, p = 0.011). Conclusion Based on this study, it is thought that chronic pre- and post-natal period exposure to wireless internet frequency of EMF may cause chronic kidney damages; staying away from EMF source in especially pregnancy and early childhood period may reduce negative effects of exposure on kidney. PMID:26905323

  12. Elk3 Deficiency Causes Transient Impairment in Post-Natal Retinal Vascular Development and Formation of Tortuous Arteries in Adult Murine Retinae

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    Christine Weinl; Christine Wasylyk; Marina Garcia Garrido; Vithiyanjali Sothilingam; Beck, Susanne C.; Heidemarie Riehle; Christine Stritt; Michel J Roux; Seeliger, Mathias W.; Bohdan Wasylyk; Alfred Nordheim

    2014-01-01

    Serum Response Factor (SRF) fulfills essential roles in post-natal retinal angiogenesis and adult neovascularization. These functions have been attributed to the recruitment by SRF of the cofactors Myocardin-Related Transcription Factors MRTF-A and -B, but not the Ternary Complex Factors (TCFs) Elk1 and Elk4. The role of the third TCF, Elk3, remained unknown. We generated a new Elk3 knockout mouse line and showed that Elk3 had specific, non-redundant functions in the retinal vasculature. In E...

  13. The pathway to care in post-natal depression: women's attitudes to post-natal depression and its treatment.

    OpenAIRE

    Whitton, A; Warner, R; Appleby, L.

    1996-01-01

    Women suffering from post-natal depression were interviewed about their symptoms, help-seeking behaviour and treatment. Over 90% recognized there was something wrong, but only one-third believed they were suffering from post-natal depression. Over 80% had not reported their symptoms to any health professional.

  14. miR-200c affects the mRNA expression of E-cadherin by regulating the mRNA level of TCF8 during post-natal epididymal development in juvenile rats

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    Junfeng Wang; Kangcheng Ruan

    2010-01-01

    The unique temporal expression pattern of miR-200c in epididymis during post-natal development in juvenile rats was revealed by our home-made miRNA microarray in this paper.It was found that miR-200c expressed in the lowest level at Day 7 and then increased to the highest at Day 36 followed by a dramatic decrease.The pattern was exactly inverse to that of mRNA expression of transcrip tion factor 8(TCF8)revealed by quantitative real-time polymerase chain reaction(qRT-PCR),providing an extra evidence that TCF8 is one degradation target of miR-200c even in epididymis.Moreover,the qRT-PCR study on expression of E-cadherin and interleukin-2 indicated that miR-200c does exert an obvious effect on the mRNA expression of E-cadherin by directly regulating the mRNA level of TCF8,although the effect on interleukin-2 is not obvious as on E-cadherin,which implicates that interleukin-2 may be also regulated by other factors besides TCF8 in rat epididymis.

  15. Connexins, E-cadherin, Claudin-7 and β-catenin transiently form junctional nexuses during the post-natal mammary gland development.

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    Dianati, Elham; Poiraud, Jérémy; Weber-Ouellette, Anne; Plante, Isabelle

    2016-08-01

    Gap junctions are intercellular channels made of connexins (Cxs) that allow direct communication between adjacent cells. Modulation of Cxs has been associated with abnormal development and function of the mammary gland and breast cancer. However, the mechanisms underlying their expression during normal mammary gland are not yet known. Cxs interact with components of tight and adherens junctions. Thus, we hypothesized that the expression levels of Cxs vary during mammary gland development and are regulated through stage-dependent interactions with members of the tight and adherens junctions. Our specific objectives were to: 1) determine the expression of Cxs and tight and adherens junction proteins throughout development and 2) characterize Cxs interactions with components of tight and adherens junctions. Murine mammary glands were sampled at various developmental stages (pre-pubescent to post-weaning). RT-qPCR and western-blot analyses demonstrated differential expression patterns for all gap (Cx43, Cx32, Cx26, Cx30), tight (Claudin-1, -3, -4, -7) and adherens (β-catenin, E- and P-cadherins) junctions throughout development. Interestingly, co-immunoprecipitation demonstrated interactions between these different types of junctions. Cx30 interacted with Cx26 just at the late pregnancy stage. While Cx43 showed a persistent interaction with β-catenin from virginity to post-weaning, its interactions with E-cadherin and Claudin-7 were transient. Cx32 interacted with Cx26, E-cadherin and β-catenin during lactation. Immunofluorescence results confirmed the existence of a junctional nexus that remodeled during mammary gland development. Together, our results confirm that the expression levels of Cxs vary concomitantly and that Cxs form junctional nexuses with tight and adherens junctions, suggesting the existence of common regulatory pathways.

  16. The effect of colostrum on pigs pre-natally or post-natally exposed to Schistosoma japonicum

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    Techau, M.E.; Johansen, M.V.; Lind, Peter;

    2004-01-01

    fibrosis in pre-natally exposed pigs. These findings indicate that further investigations will prove valuable, elucidating the influence of the parasitological and immunological status of the sow, on pre-natally exposed pigs, and on the ability of these pigs to develop resistance against S. japonicum later......Pre-natal infection of Schistosoma japonicum in pigs may prove to be a useful model in shedding light on human pre-natal schistosomiasis. This study describes the effects of immune colostrum on worm burdens, tissue egg counts, liver pathology and crude worm or egg antigen-specific IgG and Ig......A responses, in groups of pigs pre-natally, pre-natally + post-natally or post-natally exposed to S. japonicum. Results suggest that pre-natal exposure and immune colostrum did not affect the establishment of a post-natal challenge infection. However, immune colostrum seemed to increase the levels of septal...

  17. Effects of environmental temperature on oxygen diffusion capacity during post-natal development in the altricial rodent, Phyllotis darwini Efectos de la temperatura ambiental sobre la capacidad de difusión de oxígeno durante el desarrollo postnatal en el roedor altricial Phyllotis darwini

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    MAURICIO CANALS

    2009-03-01

    Full Text Available In this contribution we studied the developmental phenotypic plasticity of respiratory structures involved in the exchange of gases in an altricial rodent, the leaf-eared mouse {Phyllotis darwini. We studied morphological pulmonary parameters of warm (30 °C and cold acclimated animals 15 °C at different developmental stages. We found that acclimation treatments did not affect neither lung volume, the alveolo-capillary barrier thickness nor the respiratory surface density. In consequence the oxygen diffusion capacity was not affected. Although Phyllotis darwini exhibited structural respiratory changes expected by its ontogenetic development, these structures were not affected by thermal acclimation during the post-natal development.Estudiamos la plasticidad fenotípica del desarrollo de las estructuras respiratorias responsables del intercambio de oxígeno en el roedor altricial Phyllotis darwini. Investigamos los parámetros morfológicos del pulmón en animales aclimatados a alta temperatura (bajo requerimiento energético de termorregulación: 30 °C y a baja temperatura (alto requerimiento: 15 °C en diferentes etapas del desarrollo. Encontramos que la temperatura ambiental no afectó el volumen pulmonar, el grosor de la barrera alvéolo-capilar ni la densidad de superficie alveolar. Y en consecuencia, tampoco la capacidad de difusión de oxígeno. Aun cuando Phyllotis darwini mostró los cambios respiratorios esperados de acuerdo a su desarrollo ontogénico, las estructuras evaluadas no fueron afectadas por la aclimatación térmica durante el desarrollo postnatal.

  18. Estudo longitudinal do desenvolvimento de crianças nascidas pré-termo no primeiro ano pós-natal Longitudinal study of the development of children born preterm in the first year of post-natal age

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    Fabíola Dantas Andréz Nobre

    2009-01-01

    Full Text Available O objetivo do estudo foi avaliar indicadores de desenvolvimento de crianças nascidas pré-termo e comparar o desempenho nas faixas de 5 a 7 e 10 a 14 meses de idade corrigida. Foram relacionados indicadores do desenvolvimento com variáveis neonatais e do ambiente familiar e sexo. Trinta crianças foram avaliadas pelo Denver-II. As cuidadoras responderam à entrevista e o prontuário médico foi analisado. Na faixa de 5 a 7 meses, 20 % das crianças apresentaram risco para problemas de desenvolvimento e 27% de 10 a 14 meses. Houve diferença significativa entre as fases com mais risco na linguagem na faixa de 10 a 14 meses. As crianças nascidas com menor peso e idade gestacional, que permaneceram mais tempo hospitalizadas e com situações familiares adversas apresentaram mais problemas de desenvolvimento.The aim of the study was to assess the development of children born preterm and to compare the performance in the ranges of 5-7 and 10-14 months of corrected age. The children's development indicators and the variables of neonatal period and familial environment were correlated. Thirty children were assessed by Denver-II. The caregivers were interviewed and the medical chart was examined. Twenty per cent of children presented risk for developmental problems at 5-7 months, and 27% at 10-14 months. There was statistical significant difference between ages in language, with high risk at 10-14. The children with lower birthweight, lower gestational age, longer time stay in the hospital, and with adverse family situations showed higher risk for developmental problems.

  19. The rabbit as an animal model for post-natal vitreous matrix differentiation and degeneration

    NARCIS (Netherlands)

    Los, L. I.

    2008-01-01

    Purpose This study evaluates whether rabbits are a suitable animal model to study post-natal vitreous differentiation and degeneration. Methods Human and rabbit eyes of various ages were studied by complementary anatomical techniques, light microscopy, and transmission electron microscopy. Results T

  20. Post-Natal Inhibition of NF-κB Activation Prevents Renal Damage Caused by Prenatal LPS Exposure.

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    Guo, Wei; Guan, Xiao; Pan, Xiaodong; Sun, Xiongshan; Wang, Fangjie; Ji, Yan; Huang, Pei; Deng, Yafei; Zhang, Qi; Han, Qi; Yi, Ping; Namaka, Michael; Liu, Ya; Deng, Youcai; Li, Xiaohui

    2016-01-01

    Prenatal exposure to an inflammatory stimulus has been shown to cause renal damage in offspring. Our present study explored the role of intra-renal NF-κB activation in the development of progressive renal fibrosis in offspring that underwent prenatal exposure to an inflammatory stimulus. Time-dated pregnant rats were treated with saline (control group) or 0.79 mg/kg lipopolysaccharide (LPS) through intra-peritoneal injection on gestational day 8, 10 and 12. At the age of 7 weeks, offspring from control or LPS group were treated with either tap water (Con+Ve or LPS+Ve group) or pyrollidine dithiocarbamate (PDTC, 120mg/L), a NF-κB inhibitor, via drinking water starting (Con+PDTC or LPS+PDTC group), respectively, till the age of 20 or 68 weeks. The gross structure of kidney was assessed by hematoxylin-eosin, periodic acid-Schiff staining and Sirius red staining. The expression levels of TNF-α, IL-6, α-smooth muscle actin (α-SMA) and renin-angiotensin system (RAS) genes were determined by real time polymerase chain reaction and/or immunohistochemical staining. Our data showed that post-natal persistent PDTC administration efficiently repressed intra-renal NF-κB activation, TNF-α and IL-6 expression. Post-natal PDTC also prevented intra-renal glycogen deposition and collagenous fiber generation as evident by the reduced expression of collagen III and interstitial α-SMA in offspring of prenatal LPS exposure. Furthermore, post-natal PDTC administration reversed the intra-renal renin-angiotensin system (RAS) over-activity in offspring of prenatal LPS exposure. In conclusion, prenatal inflammatory exposure results in offspring's intra-renal NF-κB activation along with inflammation which cross-talked with excessive RAS activation that caused exacerbation of renal fibrosis and dysfunction in the offspring. Thus, early life prevention of NF-κB activation may be a potential preventive strategy for chronic renal inflammation and progressive renal damage. PMID:27073902

  1. Erk1/2 but not PI3K pathway is required for neurotrophin 3-induced oligodendrocyte differentiation of post-natal neural stem cells

    Institute of Scientific and Technical Information of China (English)

    XinhuaHu; LuJin; LinyinFeng

    2005-01-01

    Neurotrophin 3 (NT3) induces mouse cortical stem cells to an asymmetric division from a symmetric division, suggesting that NT3 may work as an early differentiative signal for neural stem cells (NSCs). Here, using cultured post-natal hippocampal stem cells as a model, we demonstrated that NT3-stimulation causes NSCs to differentiate into oligodendrocyte precursors (OLPs) through an extracellular signal-related kinasel/2 (Erkl/2)-dependent pathway. Following the treatment of NT3 for 24h, NSCs differentiated into more OLPs and fewer neurons, whereas the proliferation and survival of OLPs were not affected. NT3 induced a series of intracellular responses including enhancement of phosphorylation of Erk 1/2 or Akt and increase of expression of oligodendrocyte lineage gene (Olig)-1, a transcriptional factor known to participate in oligodendrocyte development. Application of U0126, a specific inhibitor of MEK1/2 which are upstream to Erk1/2, blocked the phosphorylation of Erk1/2, suppressed the expression of Olig-1 and prevented NSC differentiation into OLPs in response to NT3 stimulation. Blockade of TrkC also inhibited the differentiation of NSCs to OLPs induced by NT3. However,administration of LY294002, an inhibitor of phosphatidylinositol 3 kinase (PI3K), blocked the phosphorylation of Akt but did not affect the effect of NT3 on the expression of Olig-1 and on NSC differentiation into OLPs. Taken together, these results suggest that NT3 induce NSCs to differentiate into OLPs by enhancing the expression of Olig-1 through an Erk1/2-dependent pathway.

  2. Challenges in the prenatal and post-natal diagnosis of mediastinal cystic hygroma: a case report

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    Nazir Sarfraz

    2008-08-01

    Full Text Available Abstract Introduction Cystic hygroma is a benign congenital neoplasm that mostly presents as a soft-tissue mass in the posterior triangle of the neck. Pure mediastinal lesions are uncommon; the vast majority are asymptomatic and are an incidental finding in adulthood. The diagnosis is often made intra- or postoperatively. Prenatal identification is exceptional and post-natal diagnosis also proves challenging. Case presentation We report one such case that was mistaken for other entities in both the prenatal and immediate post-natal period. Initial and follow-up antenatal ultrasound scans demonstrated a multicystic lesion in the left chest, and the mother was counselled about the possibility of her baby having a congenital diaphragmatic hernia. Initial post-natal chest radiographs were reported as normal. An echocardiogram and thoracic computed tomography scan confirmed a complex multiloculated cystic mediastinal mass. The working diagnoses were of a mediastinal teratoma or congenital cystic adenomatous malformation. At operation, the lesion was compressed by the left lung and was found to be close to the left phrenic nerve, which was carefully identified and preserved. After excision, histopathological examination of the mass confirmed the diagnosis of cystic hygroma. Postoperative dyspnoea was observed secondary to paradoxical movement of the left hemidiaphragm and probable left phrenic neuropraxia. This settled conservatively with excellent recovery. Conclusion Despite the fact that isolated intrathoracic cystic hygroma is a rare entity, it needs to be considered in the differential diagnosis of foetal and neonatal mediastinal masses, particularly for juxtadiaphragmatic lesions. The phrenic nerve is not identifiable on prenatal ultrasound imaging, and it is therefore understandable that a mass close to the diaphragm may be mistaken for a congenital diaphragmatic hernia because of the location, morphology and potential phrenic nerve compression

  3. Intracranial extracerebral neuroglial heterotopia with parapharyngeal extension: pre-natal and post-natal imaging findings

    OpenAIRE

    Ferraz-Filho, J R L; Torres, U S; Vaz-Oliani, D C M; A.S. Souza

    2012-01-01

    We report an unusual case of intracranial extracerebral neuroglial heterotopia (IENH) presenting with parapharyngeal extension. Neuroglial heterotopias are rarely reported pre-natally and, to our knowledge, there are no reported cases presenting pre-natal imaging findings of IENH with parapharyngeal extension. Because pre- and post-natal imaging studies are essential to diagnose IENH and plan surgical treatment, radiologists should be familiar with this rare condition.

  4. Caesarean Section, Vaginal Delivery and Post Natal Depression

    OpenAIRE

    MH Baghianimoghadam; D Shodjaee zadeh; AH Aminian

    2009-01-01

    "nBackground: Depression is a kind of sorrow that decreases the level of juiciness. Most studies have maintained that psy­chological risk factors have the most profound effect on the development of postnatal depression (PND). We compared the postnatal depression among the women with elective caesarean and vaginal delivery. "nMethods: This cross- sectional study was carried out on 120 women 1-4 months after their delivery. Samples were divided in two groups (60 mothe...

  5. Modulatory interventions in post-natal hippocampal neurogenesis : structural and functional implications

    OpenAIRE

    Silva, Rui Jorge

    2007-01-01

    Tese de doutoramento em Ciências da Saúde – Ciências Biológicas e Biomédicas Post-natal neurogenesis is one of the most interesting brain events disclosed in the last century, with its modulation promising a new approach to the treatment of some central nervous system (CNS) pathologies. Despite the expectations, its clinical application is not yet a reality, mainly because the information concerning its function and regulatory mechanisms is still insufficient. In order to bette...

  6. Post-natal growth of the gastrointestinal tract of the Siberian hamster: morphometric analysis.

    Science.gov (United States)

    Wołczuk, K; Kobak, J

    2014-12-01

    Post-natal growth of the gastrointestinal tract of the Siberian hamster was studied in newborn and 3-, 7-, 14-, 21-, 42- and 90-day-old animals. Morphometric measurements and calculations were carried out: length and internal surface of gastrointestinal tract segments, size (height, width, surface) and density of villi as well as allometric growth rate of the length and internal surface of the segments with respect to the body mass. The fastest growth rate of the gastrointestinal tract segments was noticed during the first 3 days of the post-natal life. Nevertheless, significant regional differences in their growth rate were found. The increase in the length and internal surface of the large intestine was fastest, while the smallest increase was observed in the oesophagus. All segments of the gastrointestinal tract except oesophagus exhibited a positive allometric relationship to the body mass from birth till final weaning, whereas during the post-weaning period, the increase was isometric. Thus, at birth, the gastrointestinal tract segments were relatively smaller compared with those observed in adults, but then, the gastrointestinal tract grew faster than the rest of the body and reached its adult proportions just before the transition to solid food. Most probably, reaching the adult structure of the gastrointestinal tract before the final weaning is an essential condition for the proper growth of an organism after the weaning.

  7. Post-natal heart adaptation in a knock-in mouse model of calsequestrin 2-linked recessive catecholaminergic polymorphic ventricular tachycardia.

    Science.gov (United States)

    Valle, Giorgia; Boncompagni, Simona; Sacchetto, Roberta; Protasi, Feliciano; Volpe, Pompeo

    2014-02-15

    Cardiac calsequestrin (CASQ2) contributes to intracellular Ca(2+) homeostasis by virtue of its low-affinity/high-capacity Ca(2+) binding properties, maintains sarcoplasmic reticulum (SR) architecture and regulates excitation-contraction coupling, especially or exclusively upon β-adrenergic stimulation. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease associated with cardiac arrest in children or young adults. Recessive CPVT variants are due to mutations in the CASQ2 gene. Molecular and ultra-structural properties were studied in hearts of CASQ2(R33Q/R33Q) and of CASQ2(-/-) mice from post-natal day 2 to week 8. The drastic reduction of CASQ2-R33Q is an early developmental event and is accompanied by down-regulation of triadin and junctin, and morphological changes of jSR and of SR-transverse-tubule junctions. Although endoplasmic reticulum stress is activated, no signs of either apoptosis or autophagy are detected. The other model of recessive CPVT, the CASQ2(-/-) mouse, does not display the same adaptive pattern. Expression of CASQ2-R33Q influences molecular and ultra-structural heart development; post-natal, adaptive changes appear capable of ensuring until adulthood a new pathophysiological equilibrium. PMID:24370574

  8. Role of Nanog in the maintenance of marrow stromal stem cells during post natal bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Bais, Manish V.; Shabin, Zabrina M.; Young, Megan; Einhorn, Thomas A. [Orthopaedic Research Laboratory, Department of Orthopedic Surgery, Boston University School of Medicine, Boston, MA 02118 (United States); Kotton, Darrell N. [Pulmonary Center, Boston University School of Medicine, Boston, MA 02118 (United States); Gerstnefeld, Louis C., E-mail: lgersten@bu.edu [Orthopaedic Research Laboratory, Department of Orthopedic Surgery, Boston University School of Medicine, Boston, MA 02118 (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Nanog is related to marrow stromal stem cell maintenance. Black-Right-Pointing-Pointer Increasing Nanog expression is seen during post natal surgical bone repair. Black-Right-Pointing-Pointer Nanog knockdown decreases post surgical bone regeneration. -- Abstract: Post natal bone repair elicits a regenerative mechanism that restores the injured tissue to its pre-injury cellular composition and structure and is believed to recapitulate the embryological processes of bone formation. Prior studies showed that Nanog, a central epigenetic regulator associated with the maintenance of embryonic stem cells (ESC) was transiently expressed during fracture healing, Bais et al. . In this study, we show that murine bone marrow stromal cells (MSCs) before they are induced to undergo osteogenic differentiation express {approx}50 Multiplication-Sign the background levels of Nanog seen in murine embryonic fibroblasts (MEFs) and the W20-17 murine marrow stromal cell line stably expresses Nanog at {approx}80 Multiplication-Sign the MEF levels. Nanog expression in this cell line was inhibited by BMP7 treatment and Nanog lentivrial shRNA knockdown induced the expression of the terminal osteogenic gene osteocalcin. Lentivrial shRNA knockdown or lentiviral overexpression of Nanog in bone MSCs had inverse effects on proliferation, with knockdown decreasing and overexpression increasing MSC cell proliferation. Surgical marrow ablation of mouse tibia by medullary reaming led to a {approx}3-fold increase in Nanog that preceded osteogenic differentiation during intramembranous bone formation. Lentiviral shRNA knockdown of Nanog after surgical ablation led to an initial overexpression of osteogenic gene expression with no initial effect on bone formation but during subsequent remodeling of the newly formed bone a {approx}50% decrease was seen in the expression of terminal osteogenic gene expression and a {approx}50% loss in trabecular bone mass. This

  9. Role of Nanog in the maintenance of marrow stromal stem cells during post natal bone regeneration

    International Nuclear Information System (INIS)

    Highlights: ► Nanog is related to marrow stromal stem cell maintenance. ► Increasing Nanog expression is seen during post natal surgical bone repair. ► Nanog knockdown decreases post surgical bone regeneration. -- Abstract: Post natal bone repair elicits a regenerative mechanism that restores the injured tissue to its pre-injury cellular composition and structure and is believed to recapitulate the embryological processes of bone formation. Prior studies showed that Nanog, a central epigenetic regulator associated with the maintenance of embryonic stem cells (ESC) was transiently expressed during fracture healing, Bais et al. . In this study, we show that murine bone marrow stromal cells (MSCs) before they are induced to undergo osteogenic differentiation express ∼50× the background levels of Nanog seen in murine embryonic fibroblasts (MEFs) and the W20-17 murine marrow stromal cell line stably expresses Nanog at ∼80× the MEF levels. Nanog expression in this cell line was inhibited by BMP7 treatment and Nanog lentivrial shRNA knockdown induced the expression of the terminal osteogenic gene osteocalcin. Lentivrial shRNA knockdown or lentiviral overexpression of Nanog in bone MSCs had inverse effects on proliferation, with knockdown decreasing and overexpression increasing MSC cell proliferation. Surgical marrow ablation of mouse tibia by medullary reaming led to a ∼3-fold increase in Nanog that preceded osteogenic differentiation during intramembranous bone formation. Lentiviral shRNA knockdown of Nanog after surgical ablation led to an initial overexpression of osteogenic gene expression with no initial effect on bone formation but during subsequent remodeling of the newly formed bone a ∼50% decrease was seen in the expression of terminal osteogenic gene expression and a ∼50% loss in trabecular bone mass. This loss of bone mass was accompanied by an increased ∼2- to 5-fold adipogenic gene expression and observed increase of fat cells in the

  10. Late gestation over- and undernutrition predispose for visceral adiposity in response to a post-natal obesogenic diet, but with differential impacts on glucose-insulin adaptations during fasting in lambs

    DEFF Research Database (Denmark)

    Khanal, Prabhat; Husted, Sanne Vinter; Axel, Anne Marie Dixen;

    2014-01-01

    of subcutaneous adipose tissue and induced differential physiological adaptations to fasting. This study does not suggest that exposure to gestational overnutrition will provide a protective effect against development of hyperglycaemia later in life. © 2013 Scandinavian Physiological Society.......Aim: To investigate if late gestation under- or overnutrition has similar adverse impacts on visceral adiposity, metabolic and endocrine function in sheep, and if subsequent exposure to a high-fat diet in early post-natal life exaggerates the prenatal programming outcomes later in life. Methods......, cholesterol, non-esterified fatty acids, triglyceride and lactate combined with abdominal obesity. Peri-renal fat appeared to be a particular target of a high-fat diet post-natally. Conclusion: Both prenatal under- and overnutrition predisposed for abdominal adiposity, apparently by reducing the expandability...

  11. Enhanced or reduced fetal growth induced by embryo transfer into smaller or larger breeds alters post-natal growth and metabolism in pre-weaning horses.

    Directory of Open Access Journals (Sweden)

    Pauline Peugnet

    Full Text Available In equids, placentation is diffuse and nutrient supply to the fetus is determined by uterine size. This correlates with maternal size and affects intra-uterine development and subsequent post-natal growth, as well as insulin sensitivity in the newborn. Long-term effects remain to be described. In this study, fetal growth was enhanced or restricted through ET using pony (P, saddlebred (S and draft (D horses. Control P-P (n = 21 and S-S (n = 28 pregnancies were obtained by AI. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (P-D, n = 6 and S-D, n = 8 or S embryos into P mares (S-P, n = 6, respectively. Control and experimental foals were raised by their dams and recipient mothers, respectively. Weight gain, growth hormones and glucose homeostasis were investigated in the foals from birth to weaning. Fetal growth was enhanced in P-D and these foals remained consistently heavier, with reduced T3 concentrations until weaning compared to P-P. P-D had lower fasting glucose from days 30 to 200 and higher insulin secretion than P-P after IVGTT on day 3. Euglycemic clamps in the immediate post-weaning period revealed no difference in insulin sensitivity between P-D and P-P. Fetal growth was restricted in S-P and these foals remained consistently lighter until weaning compared to S-D, with elevated T3 concentrations in the newborn compared to S-S. S-P exhibited higher fasting glycemia than S-S and S-D from days 30 to 200. They had higher maximum increment in plasma glucose than S-D after IVGTT on day 3 and clamps on day 200 demonstrated higher insulin sensitivity compared to S-D. Neither the restricted nor the enhanced fetal environment affected IGF-1 concentrations. Thus, enhanced and restricted fetal and post-natal environments had combined effects that persisted until weaning. They induced different adaptive responses in post-natal glucose metabolism: an early insulin-resistance was

  12. Lubricin is Required for the Structural Integrity and Post-natal Maintenance of TMJ.

    Science.gov (United States)

    Koyama, E; Saunders, C; Salhab, I; Decker, R S; Chen, I; Um, H; Pacifici, M; Nah, H D

    2014-07-01

    The Proteoglycan 4 (Prg4) product lubricin plays essential roles in boundary lubrication and movement in limb synovial joints, but its roles in temporomandibular joint (TMJ) are unclear. Thus, we characterized the TMJ phenotype in wild-type and Prg4 (-/-) mouse littermates over age. As early as 2 weeks of age, mutant mice exhibited hyperplasia in the glenoid fossa articular cartilage, articular disc, and synovial membrane. By 1 month of age, there were fewer condylar superficial tenascin-C/Col1-positive cells and more numerous apoptotic condylar apical cells, while chondroprogenitors displayed higher mitotic activity, and Sox9-, Col2-, and ColX-expressing chondrocyte zones were significantly expanded. Mutant subchondral bone contained numerous Catepsin K- expressing osteoclasts at the chondro-osseous junction, increased invasive marrow cavities, and suboptimal subchondral bone. Mutant glenoid fossa, disc, synovial cells, and condyles displayed higher Hyaluronan synthase 2 expression. Mutant discs also lost their characteristic concave shape, exhibited ectopic chondrocyte differentiation, and occasionally adhered to condylar surfaces. A fibrinoid substance of unclear origin often covered the condylar surface. By 6 months of age, mutant condyles displayed osteoarthritic degradation with apical/mid-zone separation. In sum, lubricin exerts multiple essential direct and indirect roles to preserve TMJ structural and cellular integrity over post-natal life. PMID:24834922

  13. Lubricin is Required for the Structural Integrity and Post-natal Maintenance of TMJ.

    Science.gov (United States)

    Koyama, E; Saunders, C; Salhab, I; Decker, R S; Chen, I; Um, H; Pacifici, M; Nah, H D

    2014-07-01

    The Proteoglycan 4 (Prg4) product lubricin plays essential roles in boundary lubrication and movement in limb synovial joints, but its roles in temporomandibular joint (TMJ) are unclear. Thus, we characterized the TMJ phenotype in wild-type and Prg4(-/-) mouse littermates over age. As early as 2 weeks of age, mutant mice exhibited hyperplasia in the glenoid fossa articular cartilage, articular disc, and synovial membrane. By 1 month of age, there were fewer condylar superficial tenascin-C/Col1-positive cells and more numerous apoptotic condylar apical cells, while chondroprogenitors displayed higher mitotic activity, and Sox9-, Col2-, and ColX-expressing chondrocyte zones were significantly expanded. Mutant subchondral bone contained numerous Catepsin K-expressing osteoclasts at the chondro-osseous junction, increased invasive marrow cavities, and suboptimal subchondral bone. Mutant glenoid fossa, disc, synovial cells, and condyles displayed higher Hyaluronan synthase 2 expression. Mutant discs also lost their characteristic concave shape, exhibited ectopic chondrocyte differentiation, and occasionally adhered to condylar surfaces. A fibrinoid substance of unclear origin often covered the condylar surface. By 6 months of age, mutant condyles displayed osteoarthritic degradation with apical/mid-zone separation. In sum, lubricin exerts multiple essential direct and indirect roles to preserve TMJ structural and cellular integrity over post-natal life.

  14. Evaluation of the Edinburgh Post Natal Depression Scale using Rasch analysis

    Directory of Open Access Journals (Sweden)

    Tennant Alan

    2006-06-01

    Full Text Available Abstract Background The Edinburgh Postnatal Depression Scale (EPDS is a 10 item self-rating post-natal depression scale which has seen widespread use in epidemiological and clinical studies. Concern has been raised over the validity of the EPDS as a single summed scale, with suggestions that it measures two separate aspects, one of depressive feelings, the other of anxiety. Methods As part of a larger cross-sectional study conducted in Melbourne, Australia, a community sample (324 women, ranging in age from 18 to 44 years: mean = 32 yrs, SD = 4.6, was obtained by inviting primiparous women to participate voluntarily in this study. Data from the EPDS were fitted to the Rasch measurement model and tested for appropriate category ordering, for item bias through Differential Item Functioning (DIF analysis, and for unidimensionality through tests of the assumption of local independence. Results Rasch analysis of the data from the ten item scale initially demonstrated a lack of fit to the model with a significant Item-Trait Interaction total chi-square (chi Square = 82.8, df = 40; p Conclusion The results of this study suggest that EPDS, in its original 10 item form, is not a viable scale for the unidimensional measurement of depression. Rasch analysis suggests that a revised eight item version (EPDS-8 would provide a more psychometrically robust scale. The revised cut points of 7/8 and 9/10 for the EPDS-8 show high levels of agreement with the original case identification for the EPDS-10.

  15. QUANTITATIVE AND HISTOCHEMICAL STUDY ON THE ADRENAL MEDULLA IN POST NATAL PERIOD OF ALBINO RAT

    Directory of Open Access Journals (Sweden)

    Wagieh k.Baiomy; Abdel-mawgood Anas; Mamdooh Ghaly; Ashraf M. Moustafa

    2009-09-01

    Full Text Available Background: The present work was based on the evaluation of histological, histochemical, and quantitative study on the adrenal medulla of the white albino rat in the different post natal age period. Material and methods:Sixty male albino rats were used in this study. The rats were classified to 4 main groups as follows: - Group one : One week old albino rats. - Group two: One month old albino rats. - Group three: Three months old albino rats. - Group four: Senile rats. Three main parameters were performed in this study, the first was the study of the morphological changes in the adrenal medulla in the different postnatal age groups. The second was concerned with the histochemical studies while the last parameter was the quantitative studies on the gland volume as well as its cellular count. These three parameters were performed by using different staining techniques. Results: The results showed that medullary cells in the early age groups were arranged in non-differentiated groups and become more differentiated in the older age groups. Both reticular and elastic fibers in the older age groups showed a definite increase especially at the region of corticomedullary zone. The different types of chromaffin cells were more observed at the old age groups. The concentration of ascorbic acid granules was more marked in the senile group. The quantitative changes were in the form of increased medullary volume especially in the old age. The number of chromaffin cells as well as the concentration of ascorbic acid contents was more noticed in the old age group. Conclusions: The differentiation of both divisions of the adrenal gland was not noticed in the early age groups. Cellular and fibrous differentiations were more seen in older age groups which may reflects an idea about the degree of gland maturation

  16. Inherent plasticity of brown adipogenesis in white fat of mice allows for recovery from effects of post-natal malnutrition.

    Directory of Open Access Journals (Sweden)

    Leslie P Kozak

    Full Text Available Interscapular brown adipose tissue (iBAT is formed during fetal development and stable for the life span of the mouse. In addition, brown adipocytes also appear in white fat depots (wBAT between 10 and 21 days of age in mice maintained at a room temperature of 23 °C. However, this expression is transient. By 60 days of age the brown adipocytes have disappeared, but they can re-emerge if the adult mouse is exposed to the cold (5 °C or treated with β3-adrenergic agonists. Since the number of brown adipocytes that can be induced in white fat influences the capacity of the mouse to resist the obese state, we determined the effects of the nutritional conditions on post-natal development (birth to 21 days of wBAT and its long-term effects on diet-induced obesity (DIO. Under-nutrition caused essentially complete suppression of wBAT in inguinal fat at 21 days of age, as indicated by expression of Ucp1 and genes of mitochondrial structure and function based upon microarray and qRT-PCR analysis, whereas over-nutrition had no discernible effects on wBAT induction. Surprisingly, the suppression of wBAT at 21 days of age did not affect DIO in adult mice maintained at 23 °C, nor did it affect the reduction in obesity or cold tolerance when DIO mice were exposed to the cold at 5 °C for one week. Gene expression analysis indicated that mice raised under conditions that suppressed wBAT at 21 days of age were able to normally induce wBAT as adults. Therefore, neither severe hypoleptinemia nor hypoinsulinemia during suckling permanently impaired brown adipogenesis in white fat. In addition, energy balance studies of DIO mice exposed to cold indicates that mice with reduced adipose stores preferentially increased food intake, whereas those with larger adipose tissue depots preferred to utilize energy from their adipose stores.

  17. High uptake of exclusive breastfeeding and reduced early post-natal HIV transmission.

    Directory of Open Access Journals (Sweden)

    Louise Kuhn

    Full Text Available BACKGROUND: Empirical data showing the clear benefits of exclusive breastfeeding (EBF for HIV prevention are needed to encourage implementation of lactation support programs for HIV-infected women in low resource settings among whom replacement feeding is unsafe. We conducted a prospective, observational study in Lusaka, Zambia, to test the hypothesis that EBF is associated with a lower risk of postnatal HIV transmission than non-EBF. METHODS AND RESULTS: As part of a randomized trial of early weaning, 958 HIV-infected women and their infants were recruited and all were encouraged to breastfeed exclusively to 4 months. Single-dose nevirapine was provided to prevent transmission. Regular samples were collected from infants to 24 months of age and tested by PCR. Detailed measurements of actual feeding behaviors were collected to examine, in an observational analysis, associations between feeding practices and postnatal HIV transmission. Uptake of EBF was high with 84% of women reporting only EBF cumulatively to 4 months. Post-natal HIV transmission before 4 months was significantly lower (p = 0.004 among EBF (0.040 95% CI: 0.024-0.055 than non-EBF infants (0.102 95% CI: 0.047-0.157; time-dependent Relative Hazard (RH of transmission due to non-EBF = 3.48 (95% CI: 1.71-7.08. There were no significant differences in the severity of disease between EBF and non-EBF mothers and the association remained significant (RH = 2.68 95% CI: 1.28-5.62 after adjusting for maternal CD4 count, plasma viral load, syphilis screening results and low birth weight. CONCLUSIONS: Non-EBF more than doubles the risk of early postnatal HIV transmission. Programs to support EBF should be expanded universally in low resource settings. EBF is an affordable, feasible, acceptable, safe and sustainable practice that also reduces HIV transmission providing HIV-infected women with a means to protect their children's lives. TRIAL REGISTRATION: ClinicalTrials.gov NCT00310726.

  18. [Development of new methods in asymmetric reactions and their applications].

    Science.gov (United States)

    Node, Manabu

    2002-01-01

    Several novel methods using chiral reagents and biocatalysts for asymmetric reactions are described. Among those reactions, asymmetric reduction via a novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction of acyclic alpha,beta-unsaturated ketones using a chiral mercapto alcohol, asymmetric synthesis of allene-1,3-dicarboxylate via crystallization induced asymmetric transformation, and improved asymmetric nitroolefination of lactones and lactames at alpha-carbon using new chiral reagents were developed. In the reactions using biocatalysts, asymmetric dealkoxycarbonylation of bicyclic beta-keto diesters having sigma-symmetry with lipase or esterase to give optically active beta-keto esters, the asymmetric reduction of bicyclic 1,3-diketones having sigma-symmetry with Baker's yeast to give optically active keto alcohols, and the asymmetric aldol reaction of glycine with threonine aldolase were also developed. The above mentioned products were effectively utilized as chiral building blocks for the asymmetric synthesis of natural products and drugs.

  19. Dlx5 and Dlx6 control uterine adenogenesis during post-natal maturation: possible consequences for endometriosis.

    Science.gov (United States)

    Bellessort, Brice; Le Cardinal, Marine; Bachelot, Anne; Narboux-Nême, Nicolas; Garagnani, Paolo; Pirazzini, Chiara; Barbieri, Ottavia; Mastracci, Luca; Jonchere, Vincent; Duvernois-Berthet, Evelyne; Fontaine, Anastasia; Alfama, Gladys; Levi, Giovanni

    2016-01-01

    Dlx5 and Dlx6 are two closely associated homeobox genes which code for transcription factors involved in the control of steroidogenesis and reproduction. Inactivation of Dlx5/6 in the mouse results in a Leydig cell defect in the male and in ovarian insufficiency in the female. DLX5/6 are also strongly expressed by the human endometrium but their function in the uterus is unknown. The involvement of DLX5/6 in human uterine pathology is suggested by their strong downregulation in endometriotic lesions and upregulation in endometrioïd adenocarcinomas. We first show that Dlx5/6 expression begins in Müllerian ducts epithelia and persists then in the uterine luminal and glandular epithelia throughout post-natal maturation and in the adult. We then use a new mouse model in which Dlx5 and Dlx6 can be simultaneously inactivated in the endometrium using a Pgr(cre/+) allele. Post-natal inactivation of Dlx5/6 in the uterus results in sterility without any obvious ovarian involvement. The uteri of Pgr(cre/+); Dlx5/6(flox/flox) mice present very few uterine glands and numerous abnormally large and branched invaginations of the uterine lumen. In Dlx5/6 mutant uteri, the expression of genes involved in gland formation (Foxa2) and in epithelial remodelling during implantation (Msx1) is significantly reduced. Furthermore, we show that DLX5 is highly expressed in human endometrial glandular epithelium and that its expression is affected in endometriosis. We conclude that Dlx5 and Dlx6 expression determines uterine architecture and adenogenesis and is needed for implantation. Given their importance for female reproduction, DLX5 and DLX6 must be regarded as interesting targets for future clinical research. PMID:26512061

  20. [Effect of pre and post natal undernutrition on components of metabolic syndrome later in life; systematic review].

    Science.gov (United States)

    Bacardí Gascón, Montserrat; Jiménez Morán, Elsa; Santillana Marín, Ernestina; Jimenez Cruz, Arturo

    2014-05-01

    Antecedentes: Un entorno intrauterino o una infancia temprana con desnutrición, pueden convertirse en factores de riesgo que aumentan la susceptibilidad de enfermedades crónicas degenerativas en etapas posteriores de la vida. La programación fetal significa que durante la etapa embrionaria pueden presentarse condiciones adversas del entorno que generan cambios en los parámetros fisiológicos que a su vez aumentan la susceptibilidad a cambios metabólicos en etapas posteriores de la vida. Objetivo: El propósito de este estudio fue analizar el efecto de la desnutrición pre y post natal en la presentación de obesidad y componentes del síndrome metabólico (SM) en etapas posteriores de la vida. Metodología: Se realizó una búsqueda electrónica de la literatura en las bases de datos de PubMed y EBSCO con el siguiente término: “Undernutrition in early life and obesity” de artículos publicados de noviembre de 1997 a enero del 2014. Se identificaron siete estudios y se anexaron seis obtenidos de otras referencias. Resultados: Se analizaron trece publicaciones de seis estudios realizados en seis países de Asia, África, Europa y Latinoamérica. Diez de los trece estudios fueron de tipo retrospectivo y la edad de la población que participó al final del estudio osciló de los 11 a los 70 años. En todos los estudios se observó una asociación entre la desnutrición pre y postnatal y la aparición de varios componentes del SM. Conclusión: En esta revisión se observó una consistente asociación entre la desnutrición pre y post natal con algún componente del SM en etapas posteriores de la vida.

  1. Plasticity in the adrenocortical response of a free-living vertebrate: the role of pre- and post-natal developmental stress.

    Science.gov (United States)

    Love, Oliver P; Williams, Tony D

    2008-09-01

    Optimal functioning of the hypothalamo-pituitary-adrenal (HPA) axis is paramount to maximizing fitness in vertebrates. Research in laboratory mammals has suggested that maternally-induced stress can cause significant variation in the responsiveness of an offspring's HPA axis involving both pre- and post-natal developmental mechanisms. However, very little is known regarding effects of maternal stress on the variability of offspring adrenocortical functioning in free-living vertebrates. Here we use an experimental approach that independently lowers the quality of both the pre- and post-natal developmental environment to examine programming and plasticity in the responsiveness of the HPA axis in fledglings of a free-living passerine, the European starling (Sturnus vulgaris). We found that mimicking a hormonal signal of poor maternal condition via an experimental pre-natal increase in yolk corticosterone decreased the subsequent responsiveness of the HPA axis in fledglings. Conversely, decreasing the quality of the post-natal developmental environment (by decreasing maternal provisioning capability via a maternal feather-clipping manipulation) increased subsequent responsiveness of the HPA axis in fledglings, apparently through direct effects on nestling body condition. The plasticity of these responses was sex-specific with smaller female offspring showing the largest increase in HPA reactivity. We suggest that pre-natal, corticosterone-induced, plasticity in the HPA axis may be a 'predictive adaptive response' (PAR): a form of adaptive developmental plasticity where the advantage of the induced phenotype is manifested in a future life-history stage. Further, we introduce a new term to define the condition-driven post-natal plasticity of the HPA axis to an unpredictable post-natal environment, namely a 'reactive adaptive response' (RAR). This study confirms that the quality of both the pre- and post-natal developmental environment can be a significant source of

  2. Mice Deficient in NF-κB p50 and p52 or RANK Have Defective Growth Plate Formation and Post-natal Dwarfism

    Institute of Scientific and Technical Information of China (English)

    Lianping Xing; Di Chen; Brendan F.Boyce

    2013-01-01

    NF-κBp50/p52 double knockout (dKO) and RANK KO mice have no osteoclasts and develop severe osteopetrosis associated with dwarfism. In contrast, Op/Op mice, which form few osteoclasts, and Src KO mice, which have osteoclasts with defective resorptive function, are osteopetrotic, but they are not dwarfed. Here, we compared the morphologic features of long bones from p50/p52 dKO, RANK KO, Op/Op and Src KO mice to attempt to explain the differences in their long bone lengths. We found that growth plates in p50/p52 dKO and RANK KO mice are significantly thicker than those in WT mice due to a 2-3-fold increase in the hypertrophic chondrocyte zone associated with normal a proliferative chondrocyte zone. This growth plate abnormality disappears when animals become older, but their dwarfism persists. Op/Op or Src KO mice have relatively normal growth plate morphology. In-situ hybridization study of long bones from p50/p52 dKO mice showed marked thickening of the growth plate region containing type 10 collagen-expressing chondrocytes. Treatment of micro-mass chondrocyte cultures with RANKL did not affect expression levels of type 2 collagen and Sox9, markers for proliferative chondrocytes, but RANKL reduced the number of type 10 collagen-expressing hypertrophic chondrocytes. Thus, RANK/NF-κB signaling plays a regulatory role in post-natal endochondral ossification that maintains hypertrophic conversion and prevents dwarfism in normal mice.

  3. Pre- and Post-Natal Stress Programming: Developmental Exposure to Glucocorticoids Causes Long-Term Brain-Region Specific Changes to Transcriptome in the Precocial Japanese Quail.

    Science.gov (United States)

    Marasco, V; Herzyk, P; Robinson, J; Spencer, K A

    2016-05-01

    Exposure to stress during early development can permanently influence an individual's physiology and behaviour, and affect its subsequent health. The extent to which elevated glucocorticoids cause such long-term 'programming' remains largely untested. In the present study, using the Japanese quail as our study species, we independently manipulated exposure to corticosterone during pre- and/or post-natal development and investigated the subsequent effects on global gene expression profiles within the hippocampus and hypothalamus upon achieving adulthood. Our results showed that the changes in transcriptome profiles in response to corticosterone exposure clearly differed between the hippocampus and the hypothalamus. We also showed that these effects depended on the developmental timing of exposure and identified brain-region specific gene expression patterns that were either: (i) similarly altered by corticosterone regardless of the developmental stage in which hormonal exposure occurred or (ii) specifically and uniquely altered by either pre-natal or post-natal exposure to corticosterone. Corticosterone-treated birds showed alterations in networks of genes that included known markers of the programming actions of early-life adversity (e.g. brain-derived neurotrophic factor and mineralocorticoid receptor within the hippocampus; corticotrophin-releasing hormone and serotonin receptors in the hypothalamus). Altogether, for the first time, these findings provide experimental support for the hypothesis that exposure to elevated glucocorticoids during development may be a key hormonal signalling pathway through which the long-term phenotypic effects associated with early-life adversity emerge and potentially persist throughout the lifespan. These data also highlight that stressors might have different long-lasting impacts on the brain transcriptome depending on the developmental stage in which they are experienced; more work is now required to relate these mechanisms to

  4. Evaluating the pre-, peri- and post-natal conditions of neonates affected by multiple congenital anomalies: a brief report

    Directory of Open Access Journals (Sweden)

    Rashidi-Nezhad A

    2013-01-01

    Full Text Available Background: Neonatal deaths stand for almost two-thirds of all deaths occurring in infants under one year of age. Congenital anomalies are responsible for 24.5% of these cases forming a highly important issue for health policy-makers.Methods: We studied the pre-, peri- and post-natal conditions of 77 patients with multiple congenital anomalies (MCA through genetic counseling at Several university Hospitals, in Tehran, Iran. The collected data were subsequently analyzed using SPSS software. Results: The patients did not have a good prognosis, demonstrating the need for the diagnosis of such diseases early in pregnancy to be of utmost importance. We screened for trisomy and nuchal translucency, which the first showed a low risk and the second showed normal results in most cases.Conclusion: Establishment of standards for prenatal diagnosis of congenital anomalies and monitoring their implementation seem to be necessary for the reduction of deaths due to congenital anomalies and infant mortality rate (IMR.

  5. Role of the pre- and post-natal environment in developmental programming of health and productivity.

    Science.gov (United States)

    Reynolds, Lawrence P; Caton, Joel S

    2012-05-01

    The concept that developmental insults (for example, poor pre- or postnatal nutrition) can have long-term consequences on health and well-being of the offspring has been termed developmental programming. In livestock, developmental programming affects production traits, including growth, body composition, and reproduction. Although low birth weight was used as a proxy for compromised fetal development in the initial epidemiological studies, based on controlled studies using livestock and other animal models in the last two decades we now know that developmental programming can occur independently of any effects on birth weight. Studies in humans, rodents, and livestock also have confirmed the critical role of the placenta in developmental programming. In addition, the central role of epigenetic regulation in developmental programming has been confirmed. Lastly, relatively simple therapeutic/management strategies designed to 'rescue' placental development and function are being developed to minimize the effects of developmental programming on health and productivity of humans, livestock, and other mammals.

  6. Sensory and Motor Characterization in the Post-natal Valproate Rat Model of Autism

    OpenAIRE

    Reynolds, Stacey; Millette, Alexandre; Devine, Darragh P.

    2012-01-01

    Although autism is diagnosed according to three core features of social deficits, communication impairments, and repetitive or stereotyped behaviors, other behavioral features such as sensory and motor impairments are present in more than 70% of individuals with autism spectrum disorders. Exposure of rat pups to the teratogen valproate during sensitive periods of brain development has been shown to elicit behavioral features associated with autism diagnosis and has been proposed as a valid an...

  7. FGF8 activates proliferation and migration in mouse post-natal oligodendrocyte progenitor cells.

    Directory of Open Access Journals (Sweden)

    Pablo Cruz-Martinez

    Full Text Available Fibroblast growth factor 8 (FGF8 is a key molecular signal that is necessary for early embryonic development of the central nervous system, quickly disappearing past this point. It is known to be one of the primary morphogenetic signals required for cell fate and survival processes in structures such as the cerebellum, telencephalic and isthmic organizers, while its absence causes severe abnormalities in the nervous system and the embryo usually dies in early stages of development. In this work, we have observed a new possible therapeutic role for this factor in demyelinating disorders, such as leukodystrophy or multiple sclerosis. In vitro, oligodendrocyte progenitor cells were cultured with differentiating medium and in the presence of FGF8. Differentiation and proliferation studies were performed by immunocytochemistry and PCR. Also, migration studies were performed in matrigel cultures, where oligodendrocyte progenitor cells were placed at a certain distance of a FGF8-soaked heparin bead. The results showed that both migration and proliferation was induced by FGF8. Furthermore, a similar effect was observed in an in vivo demyelinating mouse model, where oligodendrocyte progenitor cells were observed migrating towards the FGF8-soaked heparin beads where they were grafted. In conclusion, the results shown here demonstrate that FGF8 is a novel factor to induce oligodendrocyte progenitor cell activation, migration and proliferation in vitro, which can be extrapolated in vivo in demyelinated animal models.

  8. The post-natal fate of supernumerary ribs in rat teratogenicity studies.

    Science.gov (United States)

    Wickramaratne, G A

    1988-04-01

    A common occurrence in rat teratology studies, supernumerary ribs, have been considered to be indicative of teratogenicity by some authors but not to be so indicative by others. As a teratogenic event is, by definition a permanent change, a study to follow the fate of supernumerary ribs in the development of adulthood of the rat was undertaken. An established teratogen in the rat, aspirin, was used to increase the frequency of supernumerary ribs. Even though aspirin treatment of the dams doubled the initial frequency of supernumerary ribs the results show that over the first 60 days post-partum their frequency in both control and treated groups decline to essentially zero. This decline in frequency of supernumerary ribs is complemented by an increase in the proportion of foetuses with a fully developed transverse process on the first lumbar vertebra. The proposal that supernumerary ribs in the rat are a result of developmental delays in a labile region of the axial skeleton and not a manifestation of a teratogenic event is presented.

  9. Infants' Peripheral Blood Lymphocyte Composition Reflects Both Maternal and Post-Natal Infection with Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Odilon Nouatin

    Full Text Available Maternal parasitoses modulate fetal immune development, manifesting as altered cellular immunological activity in cord blood that may be linked to enhanced susceptibility to infections in early life. Plasmodium falciparum typifies such infections, with distinct placental infection-related changes in cord blood exemplified by expanded populations of parasite antigen-specific regulatory T cells. Here we addressed whether such early-onset cellular immunological alterations persist through infancy. Specifically, in order to assess the potential impacts of P. falciparum infections either during pregnancy or during infancy, we quantified lymphocyte subsets in cord blood and in infants' peripheral blood during the first year of life. The principal age-related changes observed, independent of infection status, concerned decreases in the frequencies of CD4+, NKdim and NKT cells, whilst CD8+, Treg and Teff cells' frequencies increased from birth to 12 months of age. P. falciparum infections present at delivery, but not those earlier in gestation, were associated with increased frequencies of Treg and CD8+ T cells but fewer CD4+ and NKT cells during infancy, thus accentuating the observed age-related patterns. Overall, P. falciparum infections arising during infancy were associated with a reversal of the trends associated with maternal infection i.e. with more CD4+ cells, with fewer Treg and CD8+ cells. We conclude that maternal P. falciparum infection at delivery has significant and, in some cases, year-long effects on the composition of infants' peripheral blood lymphocyte populations. Those effects are superimposed on separate and independent age- as well as infant infection-related alterations that, respectively, either match or run counter to them.

  10. Developing a Practical Chiral Toolbox for Asymmetric Catalytic Reactions

    Institute of Scientific and Technical Information of China (English)

    ZHANG; XuMu

    2001-01-01

    Chiral Quest's Toolbox Approach: During the last several decades, chemists have made major progress in discovering man-made catalysts to perform challenging asymmetric transformations. However, there is no universal chiral ligand or catalyst for solving problems in enantioselective transformations. The focus of Chiral Quest's research is to develop a useful chiral toolbox for strategically important asymmetric catalytic reactions by inventing a diverse set of novel chiral ligands and combining them with transition metals as effective enantioselective catalysts. The toolbox approach addresses significant problems in organic stereochemistry and has resulted in practical methods for the synthesis of chiral pharmaceuticals and agrochemicals  ……

  11. Developing a Practical Chiral Toolbox for Asymmetric Catalytic Reactions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Chiral Quest's Toolbox Approach: During the last several decades, chemists have made major progress in discovering man-made catalysts to perform challenging asymmetric transformations. However, there is no universal chiral ligand or catalyst for solving problems in enantioselective transformations. The focus of Chiral Quest's research is to develop a useful chiral toolbox for strategically important asymmetric catalytic reactions by inventing a diverse set of novel chiral ligands and combining them with transition metals as effective enantioselective catalysts. The toolbox approach addresses significant problems in organic stereochemistry and has resulted in practical methods for the synthesis of chiral pharmaceuticals and agrochemicals

  12. Development of chiral sulfoxide ligands for asymmetric catalysis.

    Science.gov (United States)

    Trost, Barry M; Rao, Meera

    2015-04-20

    Nitrogen-, phosphorus-, and oxygen-based ligands with chiral backbones have been the historic workhorses of asymmetric transition-metal-catalyzed reactions. On the contrary, sulfoxides containing chirality at the sulfur atom have mainly been used as chiral auxiliaries for diastereoselective reactions. Despite several distinct advantages over traditional ligand scaffolds, such as the proximity of the chiral information to the metal center and the ability to switch between S and O coordination, these compounds have only recently emerged as a versatile class of chiral ligands. In this Review, we detail the history of the development of chiral sulfoxide ligands for asymmetric catalysis. We also provide brief descriptions of metal-sulfoxide bonding and strategies for the synthesis of enantiopure sulfoxides. Finally, insights into the future development of this underutilized ligand class are discussed.

  13. Asymmetric cell division during T cell development controls downstream fate

    Science.gov (United States)

    Pham, Kim; Shimoni, Raz; Charnley, Mirren; Ludford-Menting, Mandy J.; Hawkins, Edwin D.; Ramsbottom, Kelly; Oliaro, Jane; Izon, David; Ting, Stephen B.; Reynolds, Joseph; Lythe, Grant; Molina-Paris, Carmen; Melichar, Heather; Robey, Ellen; Humbert, Patrick O.; Gu, Min

    2015-01-01

    During mammalian T cell development, the requirement for expansion of many individual T cell clones, rather than merely expansion of the entire T cell population, suggests a possible role for asymmetric cell division (ACD). We show that ACD of developing T cells controls cell fate through differential inheritance of cell fate determinants Numb and α-Adaptin. ACD occurs specifically during the β-selection stage of T cell development, and subsequent divisions are predominantly symmetric. ACD is controlled by interaction with stromal cells and chemokine receptor signaling and uses a conserved network of polarity regulators. The disruption of polarity by deletion of the polarity regulator, Scribble, or the altered inheritance of fate determinants impacts subsequent fate decisions to influence the numbers of DN4 cells arising after the β-selection checkpoint. These findings indicate that ACD enables the thymic microenvironment to orchestrate fate decisions related to differentiation and self-renewal. PMID:26370500

  14. Effect of a low glycaemic index diet in gestational diabetes mellitus on post-natal outcomes after 3 months of birth: a pilot follow-up study.

    Science.gov (United States)

    Louie, Jimmy Chun Yu; Markovic, Tania P; Ross, Glynis P; Foote, Deborah; Brand-Miller, Jennie C

    2015-07-01

    A low glycaemic index (LGI) diet during pregnancy complicated by gestational diabetes mellitus (GDM) may offer benefits to the mother and infant pair beyond those during pregnancy. We aimed to investigate the effect of an LGI diet during pregnancy complicated with GDM on early post-natal outcomes. Fifty-eight women (age: 23-41 years; mean ± SD pre-pregnancy body mass index: 24.5 ± 5.6 kg m(-2) ) who had GDM and followed either an LGI diet (n = 33) or a conventional high-fibre diet (HF; n = 25) during pregnancy had a 75-g oral glucose tolerance test and blood lipid tests at 3 months post-partum. Anthropometric assessments were conducted for 55 mother-infant pairs. The glycaemic index of the antenatal diets differed modestly (mean ± SD: 46.8 ± 5.4 vs. 52.4 ± 4.4; P diet during pregnancy complicated by GDM has outcomes similar to those of a conventional healthy diet. Adequately powered studies should explore the potential beneficial effects of LGI diet on risk factors for chronic disease.

  15. The effect of contraceptive counselling in the pre and post-natal period on contraceptive use at three months after delivery among Italian and immigrant women

    Directory of Open Access Journals (Sweden)

    Laura Lauria

    2014-03-01

    Full Text Available INTRODUCTION: Contraceptive counselling in the pre and post-natal period may be important for the use of postpartum contraception and prevention of induced abortion. This paper evaluates the use of postpartum contraceptives and the factors associated with it in a sample of Italian and immigrant women. MATERIALS AND METHODS: Data are drawn from two population-based follow-up surveys conducted to evaluate the quality of maternal care in 25 Italian Local Health Units in 2008/9 and 2010/1. Descriptive analyses and logistic regression models for complex survey data were used. RESULTS: The use of effective contraceptives in the postpartum period is similar between Italians and immigrants (65%. Fifty-nine percent of Italians and 63% of immigrants received contraceptive counselling by natal care services. Women who received counselling are more likely to use effective contraceptives (Italians OR = 2.55 95% CI 2.06 - 3.14; immigrants OR = 4.01 95% CI 2.40 - 6.70. CONCLUSIONS: This study supports the notion that health professionals should take every opportunity during pregnancy, childbirth and puerperium to provide information and counselling to improve knowledge and awareness of contraception.

  16. Instrument for an integrated: pre-natal and post-natal care Instrumento para a atenção integral: do pré-natal ao puerpério

    OpenAIRE

    Maria Inez Padula Anderson; Alexandre Borges Fortes; Miriam Schenker

    2010-01-01

    This work presents an instrument to aid the general practitioner and other health professionals in providing integrated healthcare during the pre- and post-natal period. It is believed that through an integrated approach to the psychosocial well-being not only of the pregnant women but of the couple (and at times of the whole family) it is possible to create resilience and with this, according to pshyconeuroendocrinoimmunology studies, promote health and lower the chances of falling ...

  17. Clinical Study on the Effect of Post-natal Depression on Perinatal Women%产后抑郁对孕产期妇女影响的临床研究

    Institute of Scientific and Technical Information of China (English)

    马莉

    2011-01-01

    目的 探讨产后抑郁对产妇阴道流血量、初乳始动时间及泌乳量的影响.方法 回顾性分析100例孕产妇,其中正常组84例,产后抑郁组16例.记录产后阴道流血量、初乳始动时间及泌乳量.结果 产后抑郁组24h阴道流血量及产后泌乳时间明显高于正常对照组,而泌乳量明显低于正常对照组,差异具有统计学意义(P<0.01).结论 产妇抑郁对泌乳与产后出血有不良影响,应加强对孕产妇心理健康指导.%Objective To discuss the effect of post-natal depression on vaginal bleeding and lactation.Methods A retrospective analysis of 100 cases with complete information,including 84 cases of the control group, 16 cases of post-natal depression,record the post-natal vaginal bleeding and lactation situation.Results The post-natal depression group 24h amount of vaginal bleeding after childbirth and lactation period was significantly higher than control group,while the volume of lactation was significantly lower than control group(P<0.01).Conclusion The depression might negatively affect the lactation and bleeding , it is should strengthen the guidance on maternal mental health.

  18. Asymmetric New Product Development Alliances: Win-Win or Win-Lose Partnerships?

    OpenAIRE

    Kartik Kalaignanam; Venkatesh Shankar; Rajan Varadarajan

    2007-01-01

    Interorganizational alliances are widely recognized as critical to product innovation, particularly in high-technology markets. Many new product development (NPD) alliances tend to be asymmetric, that is, they are formed between a larger firm and a smaller firm. As is the case with alliances in general, asymmetric alliances also typically result in changes in the shareholder values of the partner firms. Are the changes in shareholder values of the partner firms significant? Are asymmetric NPD...

  19. Self-help groups can improve utilization of post-natal care by HIV-positive mothers

    NARCIS (Netherlands)

    T.A. Nguyen; P. Oosterhoff; P.N. Yen; P. Wright; A. Hardon

    2009-01-01

    HIV prevention within maternal-child health services has increased in many developing countries, but many HIV-infected women in developing countries still receive insufficient postnatal care. This study explored the experience of 30 HIV-infected women in Vietnam in accessing HIV-related postnatal ca

  20. Isolation and characterization of primary microglia from post-natal murine brain tissues: a comparison of two methods.

    Science.gov (United States)

    Jose, Shinsmon; Tan, Shi Wei; Tong, Chih Kong; Vidyadaran, Sharmili

    2015-12-01

    Microglia are resident macrophages of the central nervous system (CNS). Apart from playing vital roles as sentinel cells, they are crucial in physiological processes such as synaptic pruning during brain development. CNS disorders require an understanding of the contribution of each cellular compartment to the pathogenesis. Elucidating the role of microglia in disease development and progression in the intricate CNS environment is technically challenging and requires the establishment of reliable, reproducible techniques to isolate and culture microglia. A number of different protocols have been developed for isolation of neonatal microglia and here we compare two widely used methods, namely, mild trypsinization and EasySep® magnetic separation. EasySep® magnetic separation provided higher microglia yield, and flow cytometric evaluation of CD11b and F4/80 markers revealed that EasySep® separation method also produced significantly higher purity compared to mild trypsinization. Microglia isolated using EasySep® separation method were functional, as demonstrated by the generation of nitric oxide, IL-6, TNF-α, and MCP-1 in response to lipopolysaccharide stimulation. In summary, this study has revealed that magnetic separation is superior to mild trypsinization in terms of yield and purity of microglia.

  1. Deletion of Atoh1 disrupts Sonic Hedgehog signaling in the developing cerebellum and prevents medulloblastoma

    OpenAIRE

    Flora, Adriano; Klisch, Tiemo J.; Schuster, Gabriele; Zoghbi, Huda Y.

    2009-01-01

    Granule neuron precursors (GNPs) are the most actively proliferating cells in the post-natal nervous system and mutations in pathways controlling their cell cycle can result in medulloblastoma. The transcription factor Atoh1 has been suspected to contribute to GNP proliferation, but its role in normal and neoplastic post-natal cerebellar development remains unexplored. We show that Atoh1 regulates the signal transduction pathway of Sonic Hedgehog, an extracellular factor that is essential for...

  2. Unique molecular signatures influencing the biological function and fate of post-natal stem cells isolated from different sources.

    Science.gov (United States)

    Abu Kasim, Noor Hayaty; Govindasamy, Vijayendran; Gnanasegaran, Nareshwaran; Musa, Sabri; Pradeep, Padmaja Jayaprasad; Srijaya, Thekkeparambil Chandrabose; Aziz, Zeti Adura Che Ab

    2015-12-01

    The discovery of mesenchymal stem cells (MSCs) from a myriad of tissues has triggered the initiative of establishing tailor-made stem cells for disease-specific therapy. Nevertheless, lack of understanding on the inherent differential propensities of these cells may restrict their clinical outcome. Therefore, a comprehensive study was done to compare the proliferation, differentiation, expression of cell surface markers and gene profiling of stem cells isolated from different sources, viz. bone marrow, Wharton's jelly, adipose tissue and dental pulp. We found that although all MSCs were phenotypically similar to each other, Wharton's jelly (WJ) MSCs and dental pulp stem cells (DPSCs) were highly proliferative as compared to bone marrow (BM) MSCs and adipose tissue (AD) MSCs. Moreover, indistinguishable cell surface characteristics and differentiation capacity were confirmed to be similar among all cell types. Based on gene expression profiling, we postulate that BM-MSCs constitutively expressed genes related to inflammation and immunodulation, whereas genes implicated in tissue development were highly expressed in AD-MSCs. Furthermore, the transcriptome profiling of WJ-MSCs and DPSCs revealed an inherent bias towards the neuro-ectoderm lineage. Based on our findings, we believe that there is no unique master mesenchymal stem cell that is appropriate to treat all target diseases. More precisely, MSCs from different sources exhibit distinct and unique gene expression signatures that make them competent to give rise to specific lineages rather than others. Therefore, stem cells should be subjected to rigorous characterization and utmost vigilance needs to be adopted in order to choose the best cellular source for a particular disease.

  3. Investigate the Affect of Post-natal Care Intervention on Breastfeeding Rates and Duration%浅谈进行产后护理干预对母乳喂养率及持续时间的影响

    Institute of Scientific and Technical Information of China (English)

    付雅铭

    2015-01-01

    目的:探讨产后护理干预对母乳喂养率及持续时间的影响效果。方法收集我院2013年1月~2014年6月收治的1600例产妇按是否愿意接受产后护理干预分为两组。对照组产妇给予常规护理,实验组产妇加施产后护理,比较两组产妇母乳喂养率、母乳喂养持续时间与自信心情况等。结果实验组产妇母乳喂养率高于对照组,差异具有统计学意义(P<0.01);实验组产妇母乳喂养持续时间与BSES评分高于对照组,差异具有统计学意义(P<0.01)。结论产后护理干预对母乳喂养率及持续时间的影响效果显著。%Objective Investigate the affect of post-natal care intervention on breastfeeding rates and duration.MethodsColected in our hospital from January 2013 to June 2014 were treated 1 600 cases of maternal press are wiling to accept post-natal care interventions into two groups. Control groups were given routine care,the experimental groups were applied on post-natal care,maternal breastfeeding rates between the two groups,duration of breastfeeding and self-confidence and so on.ResultsExperimental groups were significantly higher than the rate of breastfeeding,there was a significant difference statisticaly significant(P< 0.01),the experimental groups were breastfeeding duration and BSES score significantly higher,there was a significant difference,statisticaly significant(P< 0.01).Conclusion Postpartum care intervention on breastfeeding rates and duration affect the results significantly.

  4. Late gestation under- and overnutrition have differential impacts when combined with a post-natal obesogenic diet on glucose-lactate-insulin adaptations during metabolic challenges in adolescent sheep

    DEFF Research Database (Denmark)

    Khanal, Prabhat; Axel, Anne Marie Dixen; Kongsted, Anna Hauntoft;

    2015-01-01

    for the last 6 weeks of gestation (term = 147 days) assigned to HIGH (N = 13; 150 and 110% of energy and protein requirements, respectively), NORM (N = 9; 100% of requirements) or LOW (N = 14; 50% of requirements) diets. The twin offspring were raised on high-carbohydrate-high-fat (HCHF; N = 35......AIM: To determine whether late gestation under- and overnutrition programme metabolic plasticity in a similar way, and whether metabolic responses to an obesogenic diet in early post-natal life depend on the foetal nutrition history. METHODS: In a 3 × 2 factorial design, twin-pregnant ewes were......) or conventional (CONV; N = 35) diets from 3 days to 6 months of age (around puberty). Then intravenous glucose (GTT; overnight fasted), insulin (ITT; fed) and propionate (gluconeogenetic precursor; PTT; both fed and fasted) tolerance tests were conducted to evaluate (hepatic) metabolic plasticity. RESULTS...

  5. Role of SCHIZORIZA in asymmetric cell division, cell fate segregation and specification in Arabidopsis root development

    NARCIS (Netherlands)

    Jansweijer, V.M.A.

    2013-01-01

    Multicellular organisms develop their large variety of cell types from just one single cell, the zygote. Both plants and animals use asymmetric cell division to establish a multicellular body plan How different cell and tissue types are determined, how patterns are created and maintained, and which

  6. Development of New Chiral Bicyclic Ligands : Applications in Catalytic Asymmetric Transfer Hydrogenation, Epoxidations, and Epoxide Rearrangements

    OpenAIRE

    Gayet, Arnaud

    2005-01-01

    This thesis describes the synthesis and application of new chiral bicyclic ligands and their application in asymmetric catalysis. The studies involved: [i] The development of novel chiral bicyclic amino sulfur ligands and their use in transfer hydrogenation. [ii] The development of the kinetic resolution of racemic epoxide through the use of chiral lithium amides. [iii] The synthesis and application of chiral bicyclic amine in the organocatalysed epoxidation of alkenes. [iv] Development and a...

  7. Development of Asymmetric Hydrogenation Catalysts via High Throughput Experimentation

    NARCIS (Netherlands)

    Vries, J.G. de; Lefort, L.

    2013-01-01

    The dynamics of drugs discovery imposes severe time constraints on the development chemist in charge of implementing the large scale production of a new Active Pharmaceutical Ingredient (API). This results in the use of well-established and robust transformations at the expense of the cost-efficienc

  8. Rockets and Feathers : Asymmetric Petroleum Product Pricing in Developing Countries

    OpenAIRE

    Bacon, Robert; Kojima, Masami

    2010-01-01

    This paper aims to provide those working in developing countries with a review of the issues that can help address the four questions: 1) are petroleum product margins excessively high at certain times?; 2) Does asymmetry of price responses to cost changes exist and, if so, what are the possible reasons that could account for it?; 3) If there is asymmetry of petroleum product price respons...

  9. Corticotropin-releasing factor receptor types 1 and 2 are differentially expressed in pre- and post-synaptic elements in the post-natal developing rat cerebellum

    NARCIS (Netherlands)

    Swinny, JD; Kalicharan, D; Blaauw, EH; Ijkema-Paassen, J; Shi, F; Gramsbergen, A; van der Want, JJL

    2003-01-01

    Corticotropin-releasing factor (CRF)-like proteins act via two G-protein-coupled receptors (CRF-R1 and CRF-R2) playing important neuromodulatory roles in stress responses and synaptic plasticity. The cerebellar expression of corticotropin-releasing factor-like ligands has been well documented, but t

  10. Asymmetric Hearing During Development: The Aural Preference Syndrome and Treatment Options.

    Science.gov (United States)

    Gordon, Karen; Henkin, Yael; Kral, Andrej

    2015-07-01

    Deafness affects ∼2 in 1000 children and is one of the most common congenital impairments. Permanent hearing loss can be treated by fitting hearing aids. More severe to profound deafness is an indication for cochlear implantation. Although newborn hearing screening programs have increased the identification of asymmetric hearing loss, parents and caregivers of children with single-sided deafness are often hesitant to pursue therapy for the deaf ear. Delayed intervention has consequences for recovery of hearing. It has long been reported that asymmetric hearing loss/single-sided deafness compromises speech and language development and educational outcomes in children. Recent studies in animal models of deafness and in children consistently show evidence of an "aural preference syndrome" in which single-sided deafness in early childhood reorganizes the developing auditory pathways toward the hearing ear, with weaker central representation of the deaf ear. Delayed therapy consequently compromises benefit for the deaf ear, with slow rates of improvement measured over time. Therefore, asymmetric hearing needs early identification and intervention. Providing early effective stimulation in both ears through appropriate fitting of auditory prostheses, including hearing aids and cochlear implants, within a sensitive period in development has a cardinal role for securing the function of the impaired ear and for restoring binaural/spatial hearing. The impacts of asymmetric hearing loss on the developing auditory system and on spoken language development have often been underestimated. Thus, the traditional minimalist approach to clinical management aimed at 1 functional ear should be modified on the basis of current evidence. PMID:26055845

  11. Developments in asymmetric catalysis by metal complexes of chiral chelating nitrogen-donor ligands.

    Science.gov (United States)

    Caputo, Christine A; Jones, Nathan D

    2007-11-01

    In part because of their straightforward and modular syntheses from readily available enantiopure starting materials, and their capacity to bind a wide variety of transition metals, chiral, chelating nitrogen-donor ligands have played a prominent role in asymmetric catalysis. A large number of highly enantioselective transformations rely upon these ligands whose reported classes are built around amine, imine, pyrrole, pyrrolidine, oxazoline and oxazolidine donor groups, among others. In this Perspective, we examine a selection of transformative developments in asymmetric catalysis by metal complexes of bi- and polydentate members of this ligand family. We describe approaches to ligand design and synthesis, structure and bonding in coordination complexes, and limitations and future challenges. PMID:17940641

  12. Development of asymmetric membrane capsules of metformin hydrochloride for oral osmotic controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Venkatesh Teja Banala

    2014-01-01

    Full Text Available Asymmetric membrane capsules are one of the novel osmotic delivery devices which offer the delivery of a wide range of drugs in a controlled manner. In the present work, we developed a semi-automatic process by fabricating a hydraulic assisted mechanical robotic arm for the manufacturing of asymmetric membrane capsules and the process was validated in comparison with the manual procedure of manufacturing. The capsule walls were made by dip coating phase inversion process using cellulose acetate butyrate as polymer and propylene glycol as plasticizer/pore forming agent. The comparative examination of physical parameters in manual and semi-automatic process confirmed the consistency, reproducibility and efficiency of the semi-automatic process over manual procedure. The resulting asymmetric membrane wall was evaluated by scanning electron microscopy studies revealed the thin dense region supported on a thicker porous region. Fourier transform infrared studies showed phase inversion of the asymmetric membrane as compared to plain membrane. Osmotic release study and in vitro behavior was studied for controlled delivery of metformin hydrochloride as a model drug. In vitro release studies of the formulations showed that drug release was dependent on the concentration of pore forming agent, level of osmogents and independent of the media pH and agitation. The effect of the process variables on the drug release was optimized using 2 3 full factorial design and the release kinetics of the optimized formulation confirmed zero order kinetics with a controlled drug delivery of 13 h and the mechanism of drug release was found to be super case II transport.

  13. Instrument for an integrated: pre-natal and post-natal care Instrumento para a atenção integral: do pré-natal ao puerpério

    Directory of Open Access Journals (Sweden)

    Maria Inez Padula Anderson

    2010-11-01

    Full Text Available

    This work presents an instrument to aid the general practitioner and other health professionals in providing integrated healthcare during the pre- and post-natal period. It is believed that through an integrated approach to the psychosocial well-being not only of the pregnant women but of the couple (and at times of the whole family it is possible to create resilience and with this, according to pshyconeuroendocrinoimmunology studies, promote health and lower the chances of falling ill and/or having complications (preterm delivery, preeclampsia, infections among others.

    Este trabalho apresenta um instrumento elaborado para auxiliar o médico de Família e Comunidade, e também profissionais da saúde, no aprendizado e na prática de uma abordagem integral do pré-natal ao puerpério. Acredita-se que, abordando não apenas a gestante, mas também o casal (e por vezes a família, cuidando do bem-estar biopsicossocial, seja possível gerar resiliência e, dessa forma, com base nos estudos em psiconeuroendocrinoimunologia, promover a saúde e diminuir as chances de adoecimento e/ou complicações como parto prematuro, pré-eclampsia, infecções, dentre outras.

  14. Asymmetric catalysis in Brazil: development and potential for advancement of Brazilian chemical industry

    International Nuclear Information System (INIS)

    The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country. (author)

  15. Development and Optimization of Osmotically Controlled Asymmetric Membrane Capsules for Delivery of Solid Dispersion of Lycopene

    Directory of Open Access Journals (Sweden)

    Nitin Jain

    2014-01-01

    Full Text Available The aim of the present investigation is to develop and statistically optimize the osmotically controlled asymmetric membrane capsules of solid dispersion of lycopene. Solid dispersions of lycopene with β-cyclodextrin in different ratios were prepared using solvent evaporation method. Solubility studies showed that the solid dispersion with 1 : 5 (lycopene : β-cyclodextrin exhibited optimum solubility (56.25 mg/mL for osmotic controlled delivery. Asymmetric membrane capsules (AMCs were prepared on glass mold pins via dip coating method. Membrane characterization by scanning electron microscopy showed inner porous region and outer dense region. Central composite design response surface methodology was applied for the optimization of AMCs. The independent variables were ethyl cellulose (X1, glycerol (X2, and NaCl (X3 which were varied at different levels to analyze the effect on dependent variables (percentage of cumulative drug release (Y1 and correlation coefficient of drug release (Y2. The effect of independent variables on the response was significantly influential. The F18 was selected as optimized formulation based on percentage of CDR (cumulative drug release of 85.63% and correlation coefficient of 0.9994. The optimized formulation was subjected to analyze the effect of osmotic pressure and agitational intensity on percentage of CDR. The drug release was independent of agitational intensity but was dependent on osmotic pressure of dissolution medium.

  16. Gestational dietary protein is associated with sex specific decrease in blood flow, fetal heart growth and post-natal blood pressure of progeny.

    Directory of Open Access Journals (Sweden)

    Juan H Hernandez-Medrano

    Full Text Available The incidence of adverse pregnancy outcomes is higher in pregnancies where the fetus is male. Sex specific differences in feto-placental perfusion indices identified by Doppler assessment have recently been associated with placental insufficiency and fetal growth restriction. This study aims to investigate sex specific differences in placental perfusion and to correlate these changes with fetal growth. It represents the largest comprehensive study under field conditions of uterine hemodynamics in a monotocous species, with a similar long gestation period to the human. Primiparous 14 mo heifers in Australia (n=360 and UK (n=180 were either individually or group fed, respectively, diets with differing protein content (18, 14, 10 or 7% crude protein (CP from 60 d prior to 98 days post conception (dpc. Fetuses and placentae were excised at 98 dpc (n = 48. Fetal development an median uterine artery blood flow were assessed monthly from 36 dpc until term using B-mode and Doppler ultrasonography. MUA blood flow to the male feto-placental unit increased in early pregnancy associated with increased fetal growth. Protein restriction before and shortly after conception (-60 d up to 23 dpc increased MUA diameter and indices of velocity during late pregnancy, reduced fetal heart weight in the female fetus and increased heart rate at birth, but decreased systolic blood pressure at six months of age.Sex specific differences both in feto-placental Doppler perfusion indices and response of these indices to dietary perturbations were observed. Further, maternal diet affected development of fetal cardiovascular system associated with altered fetal haemodynamics in utero, with such effects having a sex bias. The results from this study provide further insight into the gender specific circulatory differences present in the fetal period and developing cardiovascular system.

  17. Effects of combined pre-and post-natal protein deprivation on the myenteric plexus of the esophagus of weanling rats:A histochemical, quantitative and ultrastructural study

    Institute of Scientific and Technical Information of China (English)

    Edson A Liberti; Ricardo BV Fontes; Verginia M Fuggi; Laura BM Maifrino; Romeu R Souza

    2007-01-01

    AIM: To evaluate the effects of protein deprivation on the myenteric plexus of the esophagus of weanling rats.METHODS: Pregnant female Wistar rats were divided into 2 groups: nourished (N), receiving normal diet,and undernourished (D), receiving a protein-deprived diet, which continued after birth. At twenty-one days of age, 13 esophagi from each group were submitted to light microscopy and morphometrical analysis employing the NADH diaphorase, NADPH diaphorase and acetylcholinesterase techniques. Three other esophagi from each group were evaluated with transmission electron microscopy (TEM).RESULTS: In both the NADH- and the NADPH-reactive mounts, the neurons of the N mounts were more intensely stained, while in the D esophagi only the larger neurons were reactive. Many myenteric neurons of N were intensely reactive for AChE activity but only a few neurons of D exhibited these aspects. Ultrastructural analysis revealed that the granular reticulum of N showed large numbers of ribosomes aligned on the outer surface of its regularly arranged membrane while the ribosomes of D were disposed in clusters. The chromatin was more homogeneously scattered inside the neuron nucleus of N as well as the granular component of the nucleolus was evidently more developed in this group.Statistically significant differences between N and D groups were detected in the total estimated number of neurons stained by the NADPH technique.CONCLUSION: The morphological and quantitative data shows that feeding with protein-deprived diet in 21-d old rats induces a delay in the development of the myenteric neurons of the esophagus.

  18. Lessons from development: A role for asymmetric stem cell division in cancer

    OpenAIRE

    Powell, Anne E.; Shung, Chia-Yi; Saylor, Katherine W.; Müllendorf, Karin A.; Weiss, Joseph B.; Wong, Melissa H.

    2009-01-01

    Asymmetric stem cell division has emerged as a major regulatory mechanism for physiologic control of stem cell numbers. Reinvigoration of the cancer stem cell theory suggests that tumorigenesis may be regulated by maintaining the balance between asymmetric and symmetric cell division. Therefore, mutations affecting this balance could result in aberrant expansion of stem cells. Although a number of molecules have been implicated in regulation of asymmetric stem cell division, here, we highligh...

  19. Effect of different contents of extruded linseed in the sow diet on piglet fatty acid composition and hepatic desaturase expression during the post-natal period.

    Science.gov (United States)

    de Quelen, F; Boudry, G; Mourot, J

    2013-10-01

    n-3 polyunsaturated fatty acids (n-3 PUFA) contribute to the normal growth and development of numerous organs in the piglet. The fatty acid composition of piglet tissues is linked to the fatty acid composition of sow milk and, consequently, to the composition of sow diet during the gestation and lactation period. In this study, we investigated the impact of different contents of extruded linseed in the sow diet on the fatty acid composition and desaturase gene expression of piglets. Sows received a diet containing either sunflower oil (low 18:3n-3 with 18:3n-3 representing 3% of total fatty acids) or a mixture of extruded linseed and sunflower oil (medium 18:3n-3 with 9% of 18:3n-3) or extruded linseed (high 18:3n-3 with 27% of 18:3n-3) during gestation and lactation. Fatty acid composition was evaluated on sow milk and on different piglet tissues at days 0, 7, 14, 21 and 28. The postnatal evolution of delta5 (D5D) and delta6 (D6D) desaturase mRNA expression was also measured in the liver of low 18:3n-3 and high 18:3n-3 piglets. The milk of high 18:3n-3 sows had higher proportions of n-3PUFA than that of low 18:3n-3 and medium 18:3n-3 sows. Piglets suckling the high 18:3n-3 sows had greater proportions of 18:3n-3, 20:5n-3, 22:5n-3 and 22:6n-3 in the liver, and of 22:5n-3 and 22:6n-3 in the brain than low 18:3n-3 and medium 18:3n-3 piglets. D5D and D6D mRNA expressions in piglet liver were not affected by the maternal diet at any age. In conclusion, extruded linseed in the sow diet modifies the n-3PUFA status of piglets during the postnatal period. However, a minimal content of 18:3n-3 in the sow diet is necessary to increase the n-3PUFA level in piglet liver and brain. Moreover, modifications in the n-3PUFA fatty acid composition of piglet tissue seem linked to the availability of 18:3n-3 in maternal milk and not to desaturase enzyme expression.

  20. Asymmetric forest transition driven by the interaction of socioeconomic development and environmental heterogeneity in Central America.

    Science.gov (United States)

    Redo, Daniel J; Grau, H Ricardo; Aide, T Mitchell; Clark, Matthew L

    2012-06-01

    Forest transitions (FT) have been observed in many developed countries and more recently in the developing world. However, our knowledge of FT from tropical regions is mostly derived from case studies from within a particular country, making it difficult to generalize findings across larger regions. Here we overcome these difficulties by conducting a recent (2001-2010) satellite-based analysis of trends in forest cover across Central America, stratified by biomes, which we related to socioeconomic variables associated with human development. Results show a net decrease of woody vegetation resulting from 12,201 km(2) of deforestation of moist forests and 6,825 km(2) of regrowth of conifer and dry forests. The Human Development Index was the socioeconomic variable best associated with forest cover change. The least-developed countries, Nicaragua and Guatemala, experienced both rapid deforestation of moist forests and significant recovery of conifer and dry forests. In contrast, the most developed countries, Panama and Costa Rica, had net woody vegetation gain and a more stable forest cover configuration. These results imply a good agreement with FT predictions of forest change in relation to socioeconomic development, but strong asymmetry in rates and directions of change largely dependent upon the biome where change is occurring. The FT model should be refined by incorporating ecological and socioeconomic heterogeneity, particularly in multicountry and regional studies. These asymmetric patterns of forest change should be evaluated when developing strategies for conserving biodiversity and environmental services. PMID:22615408

  1. Asymmetric Localization of Cdx2 mRNA during the First Cell-Fate Decision in Early Mouse Development

    Directory of Open Access Journals (Sweden)

    Maria Skamagki

    2013-02-01

    Full Text Available A longstanding question in mammalian development is whether the divisions that segregate pluripotent progenitor cells for the future embryo from cells that differentiate into extraembryonic structures are asymmetric in cell-fate instructions. The transcription factor Cdx2 plays a key role in the first cell-fate decision. Here, using live-embryo imaging, we show that localization of Cdx2 transcripts becomes asymmetric during development, preceding cell lineage segregation. Cdx2 transcripts preferentially localize apically at the late eight-cell stage and become inherited asymmetrically during divisions that set apart pluripotent and differentiating cells. Asymmetric localization depends on a cis element within the coding region of Cdx2 and requires cell polarization as well as intact microtubule and actin cytoskeletons. Failure to enrich Cdx2 transcripts apically results in a significant decrease in the number of pluripotent cells. We discuss how the asymmetric localization and segregation of Cdx2 transcripts could contribute to multiple mechanisms that establish different cell fates in the mouse embryo.

  2. Asymmetric development of dorsal and ventral attention networks in the human brain

    Directory of Open Access Journals (Sweden)

    Kristafor Farrant

    2015-04-01

    Full Text Available Two neural systems for goal-directed and stimulus-driven attention have been described in the adult human brain; the dorsal attention network (DAN centered in the frontal eye fields (FEF and intraparietal sulcus (IPS, and the ventral attention network (VAN anchored in the temporoparietal junction (TPJ and ventral frontal cortex (VFC. Little is known regarding the processes governing typical development of these attention networks in the brain. Here we use resting state functional MRI data collected from thirty 7 to 12 year-old children and thirty 18 to 31 year-old adults to examine two key regions of interest from the dorsal and ventral attention networks. We found that for the DAN nodes (IPS and FEF, children showed greater functional connectivity with regions within the network compared with adults, whereas adults showed greater functional connectivity between the FEF and extra-network regions including the posterior cingulate cortex. For the VAN nodes (TPJ and VFC, adults showed greater functional connectivity with regions within the network compared with children. Children showed greater functional connectivity between VFC and nodes of the salience network. This asymmetric pattern of development of attention networks may be a neural signature of the shift from over-representation of bottom-up attention mechanisms to greater top-down attentional capacities with development.

  3. Study of different routes to develop asymmetric double decker silsesquioxane (DDSQ)

    Science.gov (United States)

    Attanayake, Gayanthi Kumari

    on studies of different routes to an asymmetric DDSQ cage. DDSQ molecules possess a higher symmetry. Breaking the symmetry and selective functionalization of the DDSQ molecule would be highly desirable to fine tune the physical properties. Different routes were studied to develop an asymmetric DDSQ cage. One route is monoprotection of a hydroxyl group from four symmetrical hydroxyl groups present in the DDSQ cage using McDougal chemistry. This chemistry was applied to DDSQ cage, DDSQ(Me)(OH) and DDSQ(Me)(Hydroxypropyl)(carbinol system). The second attempt was hindering one side of the DDSQ cage using an immobilized surface. Different surface immobilized reagents such as "Red-Sil" (Reducing Silica) and Merrifield resinwere analyzed in this project as screening surfaces.

  4. Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions

    Science.gov (United States)

    Yamashita, Yasuhiro; Yoshimoto, Susumu; Dutton, Mark J

    2016-01-01

    Summary Highly efficient catalytic asymmetric [3 + 2] cycloadditions using a chiral copper amide are reported. Compared with the chiral CuOTf/Et3N system, the CuHMDS system showed higher reactivity, and the desired reactions proceeded in high yields and high selectivities with catalyst loadings as low as 0.01 mol %. PMID:27559396

  5. Gastrointestinal function development and microbiota

    OpenAIRE

    Di Mauro, Antonio; Neu, Josef; Riezzo, Giuseppe; Raimondi, Francesco; Martinelli, Domenico; Francavilla, Ruggiero; Indrio, Flavia

    2013-01-01

    The intestinal microbiota plays an important role in the development of post-natal gastrointestinal functions of the host. Recent advances in our capability to identify microbes and their function offer exciting opportunities to evaluate the complex cross talk between microbiota, intestinal barrier, immune system and the gut-brain axis. This review summarizes these interactions in the early colonization of gastrointestinal tract with a major focus on the role of intestinal microbiota in the p...

  6. The Development of Multidimensional Analysis Tools for Asymmetric Catalysis and Beyond.

    Science.gov (United States)

    Sigman, Matthew S; Harper, Kaid C; Bess, Elizabeth N; Milo, Anat

    2016-06-21

    In most modern organic chemistry reports, including many of ours, reaction optimization schemes are typically presented to showcase how reaction conditions have been tailored to augment the reaction's yield and selectivity. In asymmetric catalysis, this often involves evaluation of catalyst, solvent, reagent, and, sometimes, substrate features. Such an article will then detail the process's scope, which mainly focuses on its successes and briefly outlines the "limitations". These limitations or poorer-performing substrates are occasionally the result of obvious, significant changes to structure (e.g., a Lewis basic group binds to a catalyst), but frequently, a satisfying explanation for inferior performance is not clear. This is one of several reasons such results are not often reported. These apparent outliers are also commonplace in the evaluation of catalyst structure, although most of this information is placed in the Supporting Information. These practices are unfortunate because results that appear at first glance to be peculiar or poor are considerably more interesting than ones that follow obvious or intuitive trends. In other words, all of the data from an optimization campaign contain relevant information about the reaction under study, and the "outliers" may be the most revealing. Realizing the power of outliers as an entry point to entirely new reaction development is not unusual. Nevertheless, the concept that no data should be wasted when considering the underlying phenomena controlling the observations of a given reaction is at the heart of the strategy we describe in this Account. The idea that one can concurrently optimize a reaction to expose the structural features that control its outcomes would represent a transformative addition to the arsenal of catalyst development and, ultimately, de novo design. Herein we outline the development of a recently initiated program in our lab that unites optimization with mechanistic interrogation by

  7. Axi-asymmetric development of buoyant diapirs in analogue and numerical experiments: the role of source-layer tilts

    Science.gov (United States)

    Dutta, Urmi; Baruah, Amiya; Mandal, Nibir

    2016-04-01

    Diapiric structure owing to gravity instabilities, triggered by density inversion in the rock sequences, is a unique geodynamic manifestation. High-density layers that rest upon low-density layers tend to sink, forcing the latter to squeeze up in the form of domal shapes, called buoyant diapirs. Using two-layer viscous model experiments, we investigated the effects of source-layer tilt (β) in controlling the ascent behaviour of buoyant diapirs initiated by a Rayleigh-Taylor instability. Results from our laboratory experiments, performed with a buoyant viscous layer (PDMS; density: 965.0 kg/m3) underlying a denser fluid (water; density: 998.2 kg/m3) suggest that the diapir shape is highly sensitive to β. The results suggest that diapirs growing from a tilted source layer ascend with contrasting lateral spreading rates in the up and down slope directions, resulting in axi-asymmetric geometry. Conversely, diapirs initiated from a horizontal source layer always maintain axi- symmetric shape as they grow. Interestingly, diapir heads retain a circular outline on the horizontal top surface irrespective of their degree of symmetry. However, for the axi-asymmetric cases, the upwelling axis is shifted more in the up-slope direction, i.e. away from the centre of this circular geometry. We show a spectrum of the axi-symmetric to -asymmetric geometrical transitions as a function of the source-layer tilt (β). For large β (> 4o), the diapirs become unstable, and their stems undergo a continuous drift in the upslope direction during their vertical growth. Whilst, several studies have shown the development of axi-asymmetric diapirs, the underlain flow kinematics in the viscous layers as a function of source layer tilt leading to such shape transition remains unclear. With this objective we ran computational fluid dynamic (CFD) simulations, by employing the volume of fluid (VOF) method, to investigate the role of underlying dynamics for axi-asymmetric diapiric growth. This study

  8. Asymmetrical interhemispheric connections develop in cat visual cortex after early unilateral convergent strabismus: Anatomy, physiology and mechanisms

    Directory of Open Access Journals (Sweden)

    Emmanuel eBui Quoc

    2012-01-01

    Full Text Available In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When the latter is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, such data are sparse and incomplete. Thus, little is known about the consequences of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non deviated eye. Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute in succession to the development of the callosal maps in visual cortex.

  9. Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

    Directory of Open Access Journals (Sweden)

    Lukas Hintermann

    2011-10-01

    Full Text Available Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N–F-fluorinating reagents. Asymmetric catalysis with TADDOLato–titanium(IV dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl-dimethanol Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F–TEDA (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate in acetonitrile solution or NFSI (N-fluorobenzenesulfonimide in dichloromethane solution as fluorinating reagents. The effects of various reaction parameters and of the TADDOL ligand structure on the catalytic activity and enantioselectivity were investigated. The absolute configuration of several fluorination products was assigned through correlation. Evidence for ionization of the catalyst complex by chloride dissociation, followed by generation of titanium β-ketoenolates as key reaction intermediates, was obtained. Based on the experimental findings, a general mechanistic sketch and a steric model of induction are proposed.

  10. Low ascorbic acid and increased oxidative stress in gulo−/− mice during development

    OpenAIRE

    Harrison, Fiona E.; Meredith, M. Elizabeth; Dawes, Sean M.; Saskowski, Jeanette L.; May, James M.

    2010-01-01

    Vitamin C (ascorbic acid, AA) depletion during pre-natal and post-natal development can lead to oxidative stress in the developing brains and other organs. Such damage may lead to irreversible effects on later brain function. We studied the relationship between AA deficiency and oxidative stress during development in gulonolactone oxidase (gulo) knockout mice that are unable to synthesize their own ascorbic acid. Heterozygous gulo(+/−) mice can synthesize AA and typically have similar tissue ...

  11. Fat3 and Ena/VASP proteins influence the emergence of asymmetric cell morphology in the developing retina.

    Science.gov (United States)

    Krol, Alexandra; Henle, Steven J; Goodrich, Lisa V

    2016-06-15

    Neurons exhibit asymmetric morphologies throughout development - from migration to the elaboration of axons and dendrites - that are correctly oriented for the flow of information. For instance, retinal amacrine cells migrate towards the inner plexiform layer (IPL) and then retract their trailing processes, thereby acquiring a unipolar morphology with a single dendritic arbor restricted to the IPL. Here, we provide evidence that the Fat-like cadherin Fat3 acts during multiple stages of amacrine cell development in mice to orient overall changes in cell shape towards the IPL. Using a time-lapse imaging assay, we found that developing amacrine cells are less directed towards the IPL in the absence of Fat3, during both migration and retraction. Consistent with its predicted role as a cell-surface receptor, Fat3 functions cell-autonomously and is able to influence the cytoskeleton directly through its intracellular domain, which can bind and localize Ena/VASP family actin regulators. Indeed, a change in Ena/VASP protein distribution is sufficient to recapitulate the Fat3 mutant amacrine cell phenotype. Thus, Fat-like proteins might control the polarized development of tissues by sculpting the cytoskeleton of individual cells.

  12. Development of a large scale asymmetric synthesis of the glucocorticoid agonist BI 653048 BS H3PO4.

    Science.gov (United States)

    Reeves, Jonathan T; Fandrick, Daniel R; Tan, Zhulin; Song, Jinhua J; Rodriguez, Sonia; Qu, Bo; Kim, Soojin; Niemeier, Oliver; Li, Zhibin; Byrne, Denis; Campbell, Scot; Chitroda, Ashish; DeCroos, Phil; Fachinger, Thomas; Fuchs, Victor; Gonnella, Nina C; Grinberg, Nelu; Haddad, Nizar; Jäger, Burkhard; Lee, Heewon; Lorenz, Jon C; Ma, Shengli; Narayanan, Bikshandarkoil A; Nummy, Larry J; Premasiri, Ajith; Roschangar, Frank; Sarvestani, Max; Shen, Sherry; Spinelli, Earl; Sun, Xiufeng; Varsolona, Richard J; Yee, Nathan; Brenner, Michael; Senanayake, Chris H

    2013-04-19

    The development of a large scale synthesis of the glucocorticoid agonist BI 653048 BS H3PO4 (1·H3PO4) is presented. A key trifluoromethyl ketone intermediate 22 containing an N-(4-methoxyphenyl)ethyl amide was prepared by an enolization/bromine-magnesium exchange/electrophile trapping reaction. A nonselective propargylation of trifluoromethyl ketone 22 gave the desired diastereomer in 32% yield and with dr = 98:2 from a 1:1 diastereomeric mixture after crystallization. Subsequently, an asymmetric propargylation was developed which provided the desired diastereomer in 4:1 diastereoselectivity and 75% yield with dr = 99:1 after crystallization. The azaindole moiety was efficiently installed by a one-pot cross coupling/indolization reaction. An efficient deprotection of the 4-methoxyphenethyl group was developed using H3PO4/anisole to produce the anisole solvate of the API in high yield and purity. The final form, a phosphoric acid cocrystal, was produced in high yield and purity and with consistent control of particle size. PMID:23544738

  13. Asymmetric forest transition driven by the interaction of socioeconomic development and environmental heterogeneity in Central America

    OpenAIRE

    Redo, Daniel J.; Grau, H. Ricardo; Aide, T. Mitchell; Matthew L. Clark

    2012-01-01

    Forest transitions (FT) have been observed in many developed countries and more recently in the developing world. However, our knowledge of FT from tropical regions is mostly derived from case studies from within a particular country, making it difficult to generalize findings across larger regions. Here we overcome these difficulties by conducting a recent (2001–2010) satellite-based analysis of trends in forest cover across Central America, stratified by biomes, which we related to socioeco...

  14. Inductive interactions mediated by interplay of asymmetric signalling underlie development of adult haematopoietic stem cells.

    Science.gov (United States)

    Souilhol, Céline; Gonneau, Christèle; Lendinez, Javier G; Batsivari, Antoniana; Rybtsov, Stanislav; Wilson, Heather; Morgado-Palacin, Lucia; Hills, David; Taoudi, Samir; Antonchuk, Jennifer; Zhao, Suling; Medvinsky, Alexander

    2016-01-01

    During embryonic development, adult haematopoietic stem cells (HSCs) emerge preferentially in the ventral domain of the aorta in the aorta-gonad-mesonephros (AGM) region. Several signalling pathways such as Notch, Wnt, Shh and RA are implicated in this process, yet how these interact to regulate the emergence of HSCs has not previously been described in mammals. Using a combination of ex vivo and in vivo approaches, we report here that stage-specific reciprocal dorso-ventral inductive interactions and lateral input from the urogenital ridges are required to drive HSC development in the aorta. Our study strongly suggests that these inductive interactions in the AGM region are mediated by the interplay between spatially polarized signalling pathways. Specifically, Shh produced in the dorsal region of the AGM, stem cell factor in the ventral and lateral regions, and BMP inhibitory signals in the ventral tissue are integral parts of the regulatory system involved in the development of HSCs. PMID:26952187

  15. Asymmetric collider

    International Nuclear Information System (INIS)

    The study of CP violation in beauty decay is one of the key challenges facing high energy physics. Much work has not yielded a definitive answer how this study might best be performed. However, one clear conclusion is that new accelerator facilities are needed. Proposals include experiments at asymmetric electron-positron colliders and in fixed-target and collider modes at LHC and SSC. Fixed-target and collider experiments at existing accelerators, while they might succeed in a first observation of the effect, will not be adequate to study it thoroughly. Giomataris has emphasized the potential of a new approach to the study of beauty CP violation: the asymmetric proton collider. Such a collider might be realized by the construction of a small storage ring intersecting an existing or soon-to-exist large synchrotron, or by arranging collisions between a large synchrotron and its injector. An experiment at such a collider can combine the advantages of fixed-target-like spectrometer geometry, facilitating triggering, particle identification and the instrumentation of a large acceptance, while the increased √s can provide a factor > 100 increase in beauty-production cross section compared to Tevatron or HERA fixed-target. Beams crossing at a non-zero angle can provide a small interaction region, permitting a first-level decay-vertex trigger to be implemented. To achieve large √s with a large Lorentz boost and high luminosity, the most favorable venue is the high-energy booster (HEB) at the SSC Laboratory, though the CERN SPS and Fermilab Tevatron are also worth considering

  16. The World Bank, Support for Universities, and Asymmetrical Power Relations in International Development

    Science.gov (United States)

    Collins, Christopher S.; Rhoads, Robert A.

    2010-01-01

    This article examines the role of the World Bank in advancing higher education sectors in the developing world, considering in particular the increasing power and strength of a global knowledge-based economy. Given the powerful role that intergovernmental organizations such as the World Bank play in shaping global economic policies, the authors…

  17. Magnetically Modified Asymmetric Supercapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle...

  18. Cyclodextrins in Asymmetric and Stereospecific Synthesis

    Directory of Open Access Journals (Sweden)

    Fliur Macaev

    2015-09-01

    Full Text Available Since their discovery, cyclodextrins have widely been used as green and easily available alternatives to promoters or catalysts of different chemical reactions in water. This review covers the research and application of cyclodextrins and their derivatives in asymmetric and stereospecific syntheses, with their division into three main groups: (1 cyclodextrins promoting asymmetric and stereospecific catalysis in water; (2 cyclodextrins’ complexes with transition metals as asymmetric and stereospecific catalysts; and (3 cyclodextrins’ non-metallic derivatives as asymmetric and stereospecific catalysts. The scope of this review is to systematize existing information on the contribution of cyclodextrins to asymmetric and stereospecific synthesis and, thus, to facilitate further development in this direction.

  19. The Seckel syndrome and centrosomal protein Ninein localizes asymmetrically to stem cell centrosomes but is not required for normal development, behavior, or DNA damage response in Drosophila.

    Science.gov (United States)

    Zheng, Yiming; Mennella, Vito; Marks, Steven; Wildonger, Jill; Elnagdi, Esraa; Agard, David; Megraw, Timothy L

    2016-06-01

    Ninein (Nin) is a centrosomal protein whose gene is mutated in Seckel syndrome (SCKL, MIM 210600), an inherited recessive disease that results in primordial dwarfism, cognitive deficiencies, and increased sensitivity to genotoxic stress. Nin regulates neural stem cell self-renewal, interkinetic nuclear migration, and microtubule assembly in mammals. Nin is evolutionarily conserved, yet its role in cell division and development has not been investigated in a model organism. Here we characterize the single Nin orthologue in Drosophila Drosophila Nin localizes to the periphery of the centrosome but not at centriolar structures as in mammals. However, Nin shares the property of its mammalian orthologue of promoting microtubule assembly. In neural and germline stem cells, Nin localizes asymmetrically to the younger (daughter) centrosome, yet it is not required for the asymmetric division of stem cells. In wing epithelia and muscle, Nin localizes to noncentrosomal microtubule-organizing centers. Surprisingly, loss of nin expression from a nin mutant does not significantly affect embryonic and brain development, fertility, or locomotor performance of mutant flies or their survival upon exposure to DNA-damaging agents. Although it is not essential, our data suggest that Nin plays a supportive role in centrosomal and extracentrosomal microtubule organization and asymmetric stem cell division. PMID:27053665

  20. Development of a Novel, Oxidatively Activated, Safety-Catch Linker for Solid-Phase Asymmetric Organic Synthesis (SPOS)

    Institute of Scientific and Technical Information of China (English)

    LIN,Jun; Hjalmar Skarphedinsson; Stepehen G.Davies

    2004-01-01

    @@ Solid-phase asymmetric organic synthesis has become a very important synthetic strategy within the organic chemistry community.[1] Critical to success in SPOS is a linking strategy which allows both the substrate to be loaded and the product released efficiently from the polymeric support. A safety catch linker[2] (SCL) is in principle a linking molecule orthogonal to the reaction conditions of the library synthesis, which can be easily activated by a simple chemical transformation to allow efficient cleavage of the products from the polymer under mild conditions. In order to introduce the SuperQuat chiral auxiliaries[3] for SOPS, we report herein design and synthesis of a novel safety catch linker for asymmetric conjugate addition reactions.

  1. Asymmetric Ashes

    Science.gov (United States)

    2006-11-01

    that oscillate in certain directions. Reflection or scattering of light favours certain orientations of the electric and magnetic fields over others. This is why polarising sunglasses can filter out the glint of sunlight reflected off a pond. When light scatters through the expanding debris of a supernova, it retains information about the orientation of the scattering layers. If the supernova is spherically symmetric, all orientations will be present equally and will average out, so there will be no net polarisation. If, however, the gas shell is not round, a slight net polarisation will be imprinted on the light. This is what broad-band polarimetry can accomplish. If additional spectral information is available ('spectro-polarimetry'), one can determine whether the asymmetry is in the continuum light or in some spectral lines. In the case of the Type Ia supernovae, the astronomers found that the continuum polarisation is very small so that the overall shape of the explosion is crudely spherical. But the much larger polarization in strongly blue-shifted spectral lines evidences the presence, in the outer regions, of fast moving clumps with peculiar chemical composition. "Our study reveals that explosions of Type Ia supernovae are really three-dimensional phenomena," says Dietrich Baade. "The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth." "This study was possible because polarimetry could unfold its full strength thanks to the light-collecting power of the Very Large Telescope and the very precise calibration of the FORS instrument," he adds. The research team first spotted this asymmetry in 2003, as part of the same observational campaign (ESO PR 23/03 and ESO PR Photo 26/05). The new, more extensive results show that the degree of polarisation and, hence, the asphericity, correlates with the intrinsic brightness of the explosion. The brighter the supernova, the smoother, or less clumpy

  2. Asymmetric catalysis in Brazil: development and potential for advancement of Brazilian chemical industry; Catalise assimetrica no Brasil: desenvolvimento e potencialidades para o avanco da industria quimica brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Antonio Luiz, E-mail: braga.antonio@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Quimica; Luedtke, Diogo Seibert; Schneider, Paulo Henrique [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Quimica; Andrade, Leandro Helgueira [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica; Paixao, Marcio Weber [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2013-07-01

    The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country. (author)

  3. Development of metallocomplex amino acids synthons for the asymmetric preparation of α-amino acids by stereoselective introduction of a side chain. Evaluation of the model asymmetric preparation of alanine and β-13C monolabelled α-aminoisobutyric acid

    International Nuclear Information System (INIS)

    In this communication the evaluation of eleven new metallocomplex alanine synthons bearing C2-symmetric benzyl groups with electron-donating and electron-withdrawing substituents is described. α-Methylated glycine synthons (alanine complexes) were evaluated alongside alanine synthons in order to obtain a deeper understanding of the relationship between their structures and stereochemistry of monoalkylated products and to choose several candidates for their further tests for stereospecific preparation of 6-[18F]FDOPA. Glycine-derived analogues of the complexes 3-5 are the best candidates for the development of a 6-[18F]FDOPA preparation procedure. In the model epimerisation reaction they demonstrated the best performance, much better compared to the previously described compound 2. Complexes 3, 5 and 8 are the best in asymmetric preparation of β-13C monolabelled α-aminoisobutyric acid. They have to be tested in the preparation of ?-methyl amino acids like 6-[18F]-α-methylDOPA and 2-[18F]-α-methyltyrosine. (author)

  4. The future development of naval ship in asymmetric warfare%非对称战争形态下舰船装备未来发展

    Institute of Scientific and Technical Information of China (English)

    吴亚雷

    2011-01-01

    结合当前国际政治经济形势,分析了我国海军未来面临的军事挑战特点,通过对舰船装备在非对称战争中发挥的核心作用进行研究,总结了未来取胜非对称战争的关键技术,分析了舰船装备未来发展趋势,对我国海军舰船装备未来发展提出了建议.%Based on the current international political and economic situation, the characteristics of future military challenges to the navy of our country are analyzed. By research of the main role of naval ship in asymmetric warfare, the key technologies to win the future asymmetric warfare are concluded, and the future development trends of naval ship are analyzed, and some suggestions to the naval ship development of our country are proposed.

  5. Developments in catalytic asymmetric Strecker reaction of aldimines%醛亚胺的不对称Strecker反应研究进展

    Institute of Scientific and Technical Information of China (English)

    唐贝; 李高伟

    2013-01-01

    α-Aminonitriles can be easily converted to α-amino acids, and is an important intermediate for the synthesis of many biologically active natural products and drugs. The asymmetric Strecker reaction of the aldimine as a direct and affective method of synthesis of optically active α-aminonitriles has been widely accepted. In this current paper, the developments in catalytic asymmetric Strecker reaction of aldimines is introduced.%α-氨基腈不仅可以很容易地转化为α-氨基酸,而且是合成许多具有生物活性的天然产物和药物的重要中间体.醛亚胺的不对称Strecker反应作为制备光学活性α-氨基腈的直接而有效的方法之一,已被广泛接受.作者介绍了醛亚胺的不对称Strecker反应研究进展.

  6. Development and evaluation of methods for starch dissolution using asymmetrical flow field-flow fractionation. Part II: Dissolution of amylose.

    Science.gov (United States)

    Perez-Rea, Daysi; Bergenståhl, Björn; Nilsson, Lars

    2016-02-01

    In this paper, we investigate whether dissolution in water under autoclaving conditions (140 °C, 20 min) or in dimethyl sulfoxide, DMSO (100 °C, 1 h), is preferable for characterization of amylose. Two types of amylose, potato and maize, were dissolved either in water using an autoclave or in DMSO. On the aqueous solutions obtained, the extent of molecular dissolution of the sample (referred to as the dissolution yield) was determined by enzymatic analysis as well as the molecular properties, such as molar mass and root-mean-square radius, obtained with asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index detection (AF4-MALS-dRI). The results showed that both dissolution methods are efficient at dissolving amylose. However, AF4-MALS-dRI analysis revealed substantial differences. Amylose aqueous solutions obtained by dissolution in DMSO were relatively stable over time, but the dissolution method in autoclave caused some degradation of the molecules, and their solutions display a high tendency to retrograde. PMID:26232931

  7. Asymmetric Microscopic Driving Behavior Theory

    OpenAIRE

    Yeo, Hwasoo

    2008-01-01

    Numerous theories on traffic have been developed as traffic congestion gains more and more interest in our daily life. To model traffic phenomena, many traffic theorists have adopted theories from other fields such as fluid mechanics and thermodynamics. However, their efforts to model the traffic at a microscopic level have not been successful yet. Therefore, to overcome the limitations of the existing theories we propose a microscopic asymmetric traffic theory based on analysis of individual...

  8. Escala de Depressão Pós-natal de Edimburgo para triagem no sistema público de saúde Escala de Depresión Post-natal de Edimburgo para tamizage en el sistema público de salud Edinburgh Postnatal Depression Scale for screening in the public health system

    Directory of Open Access Journals (Sweden)

    Patrícia Figueira

    2009-08-01

    Full Text Available OBJETIVO: Avaliar a utilização da Escala de Depressão Pós-natal de Edimburgo como instrumento de triagem no sistema público de saúde. MÉTODOS: A Escala foi administrada entre o 40º e 90º dia do pós-parto, a 245 mulheres que tiveram parto em uma maternidade privada no município de Belo Horizonte (MG, entre 2005 e 2006. As participantes foram submetidas a uma entrevista psiquiátrica estruturada (Mini-Plus 5.0 utilizada como padrão-ouro para diagnóstico de depressão. Foram calculadas sensibilidade e especificidade da escala e utilizou-se a curva ROC para achar o melhor ponto de corte. Foi utilizado o teste t de Student para comparação das variáveis numéricas e o qui-quadrado para as variáveis categóricas. A confiabilidade foi aferida pelo coeficiente de consistência interna á de Cronbach. RESULTADOS: Foram diagnosticadas 66 mulheres com o quadro depressivo pós-parto (26,9% da amostra. Não houve diferença entre as mulheres com e sem depressão pós-parto em relação à idade, escolaridade, número de partos anteriores e estado civil. Utilizando-se o ponto de corte de 10, a sensibilidade da escala foi 86,4, a especificidade 91,1 e o valor preditivo positivo 0,78. CONCLUSÕES: As propriedades psicométricas da Escala a caracterizam como um bom instrumento de triagem da depressão pós-parto e seu uso disseminado no Sistema Único de Saúde poderia repercutir positivamente com aumento significativo na taxa de reconhecimento, diagnóstico, e tratamento da depressão pós parto.OBJETIVO: Evaluar la utilización de la Escala de Depresión Post-natal de Edimburgo como instrumento de tamizage en el sistema público de salud. MÉTODOS: La Escala fue administrada entre el 40º y 90º día de post-parto, a 245 mujeres que tuvieron parto en una maternidad privada en el municipio de Bello Horizonte (MG, entre 2005 y 2006. Las participantes fueron sometidas a una entrevista psiquiátrica estructurada (Mini-Plus 5.0 utilizada como patr

  9. Asymmetric Federalism in Russia: Cure or Poison?

    OpenAIRE

    Jorge Martinez-Vazquez

    2003-01-01

    In the early years of its existence, the Russian Federation adopted a system of differential treatment of its regions in order to cope with the great degree of diversity present in them. This paper examines the Russian Federation’s asymmetric federalism by evaluating the system’s role, significance and effects on the Federation’s development. The study incorporates a detailed description of the asymmetric federalism over time along with the benefits and costs incurred by its implementation. I...

  10. Mapping the global mRNA transcriptome during development of the murine first molar

    Directory of Open Access Journals (Sweden)

    Maria A. eLandin

    2015-02-01

    Full Text Available The main objective of this study was to map global gene expression in order to provide information about the populations of mRNA species participating in murine tooth development at 24 h intervals, starting at the eleventh embryonic day (E11.5 up to the seventh post-natal day (P7. The levels of RNA species expressed during murine tooth development were mesured using a total of 58 deoxyoligonucleotide microarrays. Microarray data was validated using real-time RT-PCR. Differentially expressed genes (p<0.05 were subjected to bioinformatic analysis to identify cellular activities significantly associated with these genes. Using ANOVA the microarray data yielded 4362 genes as being differentially expressed from the elleventh embryonic day (E11.5 up to seven days post-natal (P7, 1921 of these being genes without known functions. The remaining 2441 genes were subjected to further statistical analysis using a supervised procedure.Bioinformatic analysis results for each time-point studied suggests that the main molecular functions associated with genes expressed at the early pre-natal stages (E12.5-E18.5 studied were cell cycle progression, cell morphology, lipid metabolism, cellular growth, proliferation, senescence and apoptosis, whereas most genes expressed at post-natal and secretory stages (P0- P7 were significantly associated with regulation of cell migration, biosynthesis, differentiation, oxidative stress, polarization and cell death. Differentially expressed genes (DE not described earlier during murine tooth development; Inositol 1, 4, 5-triphosphate receptor 3 (Itpr3, metallothionein 1(Mt1, cyclin-dependent kinase 4 (Cdk4, cathepsin D (Ctsd, keratin complex 2, basic, gene 6a (Krt2-6a, cofilin 1, non-muscle (Cfl1, cyclin 2 (Ccnd2, were verified by real-time RT-PCR.

  11. Terahertz metamaterial with asymmetric transmission

    CERN Document Server

    Singh, R; Menzel, C; Rockstuhl, C; Azad, A K; Cheville, R A; Lederer, F; Zhang, W; Zheludev, N I

    2009-01-01

    We show for the first time that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials.

  12. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  13. THE ANALYSIS OF THE ASYMMETRICAL RISK IN TOURISM FOR THE DEVELOPMENT AND PROMOTION OF A LASTING REGIONAL TOURISM IDENTITY

    Directory of Open Access Journals (Sweden)

    Alexandru NEDELEA

    2009-06-01

    Full Text Available In order to establish an adequate balance between tourists' welfare, the needs of the natural and cultural environment, as well as to develop tourist destinations and organizations' competitiveness, it is necessary to carry out a global and integrated approach, where all interested parties share the same goals regarding the durability of tourism and the approached challenges. The purpose of this work is to identify the factors of reduced risk having a major impact over the sustainability of the tourist region under analysis and to highlight the risk factors' connections and impact in order to minimize and eliminate them, with direct effects over the awareness of tourist industry's values. The identification of lasting development's indicators will take into account all these three aspects of the durable development of tourism, namely ecological, economical and social factors, that play a part in highlighting the real performance of a tourist destination. All these aspects are absolutely necessary for the promotion of the Danube's tourist potential, achievable through the emphasis of the relevant values from the tourist patrimony of the county of Galati. The promotion of the Danube' tourist potential presupposes a series of objectives that are subordinated to the general direction that is marked at the national level, respectively Romania's transformation into a qualitative tourist destination based on its natural and cultural patrimony, in order to correspond to the European Union standards. The new policy regarding tourism proposed by the European Commission aims at offering constant support for this industry to be able to face different challenges, by promoting also competitiveness in general.

  14. A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

    Science.gov (United States)

    2010-01-01

    Summary The development of efficient Friedel–Crafts alkylations of arenes and heteroarenes using only catalytic amounts of a Lewis acid has gained much attention over the last decade. The new catalytic approaches described in this review are favoured over classical Friedel–Crafts conditions as benzyl-, propargyl- and allyl alcohols, or styrenes, can be used instead of toxic benzyl halides. Additionally, only low catalyst loadings are needed to provide a wide range of products. Following a short introduction about the origin and classical definition of the Friedel–Crafts reaction, the review will describe the different environmentally benign substrates which can be applied today as an approach towards greener processes. Additionally, the first diastereoselective and enantioselective Friedel–Crafts-type alkylations will be highlighted. PMID:20485588

  15. A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

    Directory of Open Access Journals (Sweden)

    Magnus Rueping

    2010-01-01

    Full Text Available The development of efficient Friedel–Crafts alkylations of arenes and heteroarenes using only catalytic amounts of a Lewis acid has gained much attention over the last decade. The new catalytic approaches described in this review are favoured over classical Friedel–Crafts conditions as benzyl-, propargyl- and allyl alcohols, or styrenes, can be used instead of toxic benzyl halides. Additionally, only low catalyst loadings are needed to provide a wide range of products. Following a short introduction about the origin and classical definition of the Friedel–Crafts reaction, the review will describe the different environmentally benign substrates which can be applied today as an approach towards greener processes. Additionally, the first diastereoselective and enantioselective Friedel–Crafts-type alkylations will be highlighted.

  16. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain asymmet

  17. An asymmetric Kadison's inequality

    CERN Document Server

    Bourin, Jean-Christophe

    2010-01-01

    Some inequalities for positive linear maps on matrix algebras are given, especially asymmetric extensions of Kadison's inequality and several operator versions of Chebyshev's inequality. We also discuss well-known results around the matrix geometric mean and connect it with complex interpolation.

  18. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  19. Asymmetric catalysis with helical polymers

    NARCIS (Netherlands)

    Megens, Rik P.; Roelfes, Gerard

    2011-01-01

    Inspired by nature, the use of helical biopolymer catalysts has emerged over the last years as a new approach to asymmetric catalysis. In this Concept article the various approaches and designs and their application in asymmetric catalysis will be discussed.

  20. Asymmetric information and economics

    Science.gov (United States)

    Frieden, B. Roy; Hawkins, Raymond J.

    2010-01-01

    We present an expression of the economic concept of asymmetric information with which it is possible to derive the dynamical laws of an economy. To illustrate the utility of this approach we show how the assumption of optimal information flow leads to a general class of investment strategies including the well-known Q theory of Tobin. Novel consequences of this formalism include a natural definition of market efficiency and an uncertainty principle relating capital stock and investment flow.

  1. Asymmetric Organocatalytic Cycloadditions

    DEFF Research Database (Denmark)

    Mose, Rasmus

    2016-01-01

    were pioneered by Otto Paul Hermann Diels and Kurt Alder who discovered what later became known as the Diels Alder reaction. The Diels Alder reaction is a [4+2] cycloaddition in which a π4 component reacts with a π2 component via a cyclic transition state to generate a 6 membered ring. This reaction...... reactions constitute the first organocatalytic asymmetric higher order cycloadditions and a rational for the periselectivity and stereoselectivity is provided based on experimental and computational investigations....

  2. Homogeneous asymmetric catalysis in fragrance chemistry.

    Science.gov (United States)

    Ciappa, Alessandra; Bovo, Sara; Bertoldini, Matteo; Scrivanti, Alberto; Matteoli, Ugo

    2008-06-01

    Opposite enantiomers of a chiral fragrance may exhibit different olfactory activities making a synthesis in high enantiomeric purity commercially and scientifically interesting. Accordingly, the asymmetric synthesis of four chiral odorants, Fixolide, Phenoxanol, Citralis, and Citralis Nitrile, has been investigated with the aim to develop practically feasible processes. In the devised synthetic schemes, the key step that leads to the formation of the stereogenic center is the homogeneous asymmetric hydrogenation of a prochiral olefin. By an appropriate choice of the catalyst and the reaction conditions, Phenoxanol, Citralis, and Citralis Nitrile were obtained in high enantiomeric purity, and odor profiles of the single enantiomers were determined.

  3. Asymmetric catalysis with short-chain peptides.

    Science.gov (United States)

    Lewandowski, Bartosz; Wennemers, Helma

    2014-10-01

    Within this review article we describe recent developments in asymmetric catalysis with peptides. Numerous peptides have been established in the past two decades that catalyze a wide variety of transformations with high stereoselectivities and yields, as well as broad substrate scope. We highlight here catalytically active peptides, which have addressed challenges that had thus far remained elusive in asymmetric catalysis: enantioselective synthesis of atropoisomers and quaternary stereogenic centers, regioselective transformations of polyfunctional substrates, chemoselective transformations, catalysis in-flow and reactions in aqueous environments.

  4. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  5. Asymmetric membrane osmotic capsules for terbutaline sulphate

    Directory of Open Access Journals (Sweden)

    N G Gobade

    2012-01-01

    Full Text Available The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate.

  6. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    Science.gov (United States)

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  7. Asymmetric quantum cloning machines

    International Nuclear Information System (INIS)

    A family of asymmetric cloning machines for quantum bits and N-dimensional quantum states is introduced. These machines produce two approximate copies of a single quantum state that emerge from two distinct channels. In particular, an asymmetric Pauli cloning machine is defined that makes two imperfect copies of a quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, characterizing the impossibility of copying imposed by quantum mechanics. If p and p' are the probabilities of the depolarizing channels associated with the two outputs, the domain in (√p,√p')-space located inside a particular ellipse representing close-to-perfect cloning is forbidden. This ellipse tends to a circle when copying an N-dimensional state with N→∞, which has a simple semi-classical interpretation. The symmetric Pauli cloning machines are then used to provide an upper bound on the quantum capacity of the Pauli channel of probabilities px, py and pz. The capacity is proven to be vanishing if (√px, √py, √pz) lies outside an ellipsoid whose pole coincides with the depolarizing channel that underlies the universal cloning machine. Finally, the tradeoff between the quality of the two copies is shown to result from a complementarity akin to Heisenberg uncertainty principle. (author)

  8. Asymmetric inclusion process

    Science.gov (United States)

    Reuveni, Shlomi; Eliazar, Iddo; Yechiali, Uri

    2011-10-01

    We introduce and explore the asymmetric inclusion process (ASIP), an exactly solvable bosonic counterpart of the fermionic asymmetric exclusion process (ASEP). In both processes, random events cause particles to propagate unidirectionally along a one-dimensional lattice of n sites. In the ASEP, particles are subject to exclusion interactions, whereas in the ASIP, particles are subject to inclusion interactions that coalesce them into inseparable clusters. We study the dynamics of the ASIP, derive evolution equations for the mean and probability generating function (PGF) of the sites’ occupancy vector, obtain explicit results for the above mean at steady state, and describe an iterative scheme for the computation of the PGF at steady state. We further obtain explicit results for the load distribution in steady state, with the load being the total number of particles present in all lattice sites. Finally, we address the problem of load optimization, and solve it under various criteria. The ASIP model establishes bridges between statistical physics and queueing theory as it represents a tandem array of queueing systems with (unlimited) batch service, and a tandem array of growth-collapse processes.

  9. Alternative Asymmetric Stochastic Volatility Models

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is

  10. Engineered Asymmetric Synthetic Vesicles

    Science.gov (United States)

    Lu, Li; Chiarot, Paul

    2013-11-01

    Synthetic vesicles are small, fluid-filled spheres that are enclosed by a bilayer of lipid molecules. They can be used as models for investigating membrane biology and as delivery vehicles for pharmaceuticals. In practice, it is difficult to simultaneously control membrane asymmetry, unilamellarity, vesicle size, vesicle-to-vesicle uniformity, and luminal content. Membrane asymmetry, where each leaflet of the bilayer is composed of different lipids, is of particular importance as it is a feature of most natural membranes. In this study, we leverage microfluidic technology to build asymmetric vesicles at high-throughput. We use the precise flow control offered by microfluidic devices to make highly uniform emulsions, with controlled internal content, that serve as templates to build the synthetic vesicles. Flow focusing, dielectrophoretic steering, and interfacial lipid self-assembly are critical procedures performed on-chip to produce the vesicles. Fluorescent and confocal microscopy are used to evaluate the vesicle characteristics.

  11. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  12. Loss Aversion and the Asymmetric Transmission of Monetary Policy

    DEFF Research Database (Denmark)

    Santoro, Emiliano; Petrella, Ivan; Pfajfar, Damjan;

    2014-01-01

    There is widespread evidence that monetary policy exerts asymmetric effects on output over contractions and expansions in economic activity, while price responses display no sizeable asymmetry. To rationalize these facts we develop a dynamic general equilibrium model where households’ utility...

  13. ASYMMETRIC-LEAVES2 and an ortholog of eukaryotic NudC domain proteins repress expression of AUXIN-RESPONSE-FACTOR and class 1 KNOX homeobox genes for development of flat symmetric leaves in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Nanako Ishibashi

    2012-01-01

    Leaf primordia form around the shoot apical meristem, which consists of indeterminate stem cells. Upon initiation of leaf development, adaxial-abaxial patterning is crucial for appropriate lateral expansion, via cellular proliferation, and the formation of flat symmetric leaves. Many genes that specify such patterning have been identified, but regulation by upstream factors of the expression of relevant effector genes remains poorly understood. In Arabidopsis thaliana, ASYMMETRIC LEAVES2 (AS2 and AS1 play important roles in repressing transcription of class 1 KNOTTED1-like homeobox (KNOX genes and leaf abaxial-determinant effector genes. We report here a mutation, designated enhancer of asymmetric leaves2 and asymmetric leaves1 (eal, that is associated with efficient generation of abaxialized filamentous leaves on the as2 or as1 background. Levels of transcripts of many abaxial-determinant genes, including ETTIN (ETT/AUXIN RESPONSE FACTOR3 (ARF3, and all four class 1 KNOX genes were markedly elevated in as2 eal shoot apices. Rudimentary patterning in as2 eal leaves was suppressed by the ett mutation. EAL encodes BOBBER1 (BOB1, an Arabidopsis ortholog of eukaryotic NudC domain proteins. BOB1 was expressed in plant tissues with division potential and bob1 mutations resulted in lowered levels of transcripts of some cell-cycle genes and decreased rates of cell division in shoot and root apices. Coordinated cellular proliferation, supported by BOB1, and repression of all class 1 KNOX genes, ETT/ARF3 by AS2 (AS1 and BOB1 might be critical for repression of the indeterminate state and of aberrant abaxialization in the presumptive adaxial domain of leaf primordia, which might ensure the formation of flat symmetric leaves.

  14. Asymmetric Gepner Models (Revisited)

    CERN Document Server

    Gato-Rivera, B

    2010-01-01

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as th...

  15. Cosmological signatures of time-asymmetric gravity

    OpenAIRE

    Cortês, Marina; Liddle, Andrew R; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar conn...

  16. Neuronal alignment on asymmetric textured surfaces

    OpenAIRE

    Beighley, Ross; Spedden, Elise; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C.; Staii, Cristian

    2012-01-01

    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here, we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify...

  17. Prospects for Asymmetric PNe with ALMA

    CERN Document Server

    Huggins, P J

    2010-01-01

    Millimeter and sub-millimeter observations have made fundamental contributions to our current understanding of the transition from AGB stars to white dwarfs. The approaching era of ALMA brings significantly enhanced observing capabilities at these wavelengths and promises to push back the frontiers in a number of ways. We examine the scientific prospects of this new era for PNe, with an emphasis on how developments may contribute to the goals of the asymmetric PNe community.

  18. Multicatalyst system in asymmetric catalysis

    CERN Document Server

    Zhou, Jian

    2014-01-01

    This book introduces multi-catalyst systems by describing their mechanism and advantages in asymmetric catalysis.  Helps organic chemists perform more efficient catalysis with step-by-step methods  Overviews new concepts and progress for greener and economic catalytic reactions  Covers topics of interest in asymmetric catalysis including bifunctional catalysis, cooperative catalysis, multimetallic catalysis, and novel tandem reactions   Has applications for pharmaceuticals, agrochemicals, materials, and flavour and fragrance

  19. On Asymmetric Quantum MDS Codes

    CERN Document Server

    Ezerman, Martianus Frederic; Ling, San

    2010-01-01

    Assuming the validity of the MDS Conjecture, the weight distribution of all MDS codes is known. Using a recently-established characterization of asymmetric quantum error-correcting codes, linear MDS codes can be used to construct asymmetric quantum MDS codes with $d_{z} \\geq d_{x}\\geq 2$ for all possible values of length $n$ for which linear MDS codes over $\\F_{q}$ are known to exist.

  20. Mobile Termination with Asymmetric Networks

    OpenAIRE

    Dewenter, Ralf; Haucap, Justus

    2003-01-01

    This paper examines mobile termination fees and their regulation when networks are asymmetric in size. It is demonstrated that with consumer ignorance about the exact termination rates (a) a mobile network?s termination rate is the higher the smaller the network?s size (as measured through its subscriber base) and (b) asymmetric regulation of only the larger operators in a market will, ce-teris paribus, induce the smaller operators to increase their termination rates. The results are supporte...

  1. Asymmetric Gepner models (revisited)

    Energy Technology Data Exchange (ETDEWEB)

    Gato-Rivera, B. [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); Schellekens, A.N., E-mail: t58@nikhef.n [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain)] [IMAPP, Radboud Universiteit, Nijmegen (Netherlands)

    2010-12-11

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as the number of families, singlets and mirrors have an interesting tendency towards smaller values as the gauge groups approaches the Standard Model. We compare our results with an analogous class of free fermionic models. This displays similar features, but with less resolution. Finally we present a complete scan of the three family models based on the triply-exceptional combination (1,16{sup *},16{sup *},16{sup *}) identified originally by Gepner. We find 1220 distinct three family spectra in this case, forming 610 mirror pairs. About half of them have the gauge group SU(3)xSU(2){sub L}xSU(2){sub R}xU(1){sup 5}, the theoretical minimum, and many others are trinification models.

  2. Cosmological signatures of time-asymmetric gravity

    CERN Document Server

    Cortês, Marina; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar connection. In this note we explore the phenomenology of this term and observational consequences for cosmological evolution. We show that constraints on the critical energy density will ordinarily render this term unobservably small, a maximum of order $10^{-25}$ of the neutrino energy density today. However, if the time-asymmetric dark energy is tuned to cancel the cosmological constant, the torsion effect may be a dark matter candidate.

  3. Asymmetric total synthesis of vindoline.

    Science.gov (United States)

    Kato, Daisuke; Sasaki, Yoshikazu; Boger, Dale L

    2010-03-24

    A concise asymmetric total synthesis of (-)-vindoline (1) is detailed based on a tandem intramolecular [4+2]/[3+2] cycloaddition cascade of a 1,3,4-oxadiazole inspired by the natural product structure, in which the tether linking the initiating dienophile and oxadiazole bears a chiral substituent that controls the facial selectivity of the initiating Diels-Alder reaction and sets absolute stereochemistry of the remaining six stereocenters in the cascade cycloadduct. This key reaction introduces three rings and four C-C bonds central to the pentacyclic ring system setting all six stereocenters and introducing essentially all the functionality found in the natural product in a single step. Implementation of the approach also required the development of a unique ring expansion reaction to provide a six-membered ring suitably functionalized for introduction of the Delta (6, 7)-double bond found in the core structure of vindoline and defined our use of a protected hydroxymethyl group as the substituent used to control the stereochemical course of the cycloaddition cascade.

  4. Modeling of asymmetrical boost converters

    Directory of Open Access Journals (Sweden)

    Eliana Isabel Arango Zuluaga

    2014-03-01

    Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.

  5. Localisation spatio-temporelle de tubuline beta III au sein l'organe de Corti et au niveau du ganglion spiral entre le 18e jours embryonnaires (E18) et le 25e jours post-natal (P25) chez le rat

    OpenAIRE

    Johnen, Nicolas; Thelen, Nicolas; Cloes, Marie; Thiry, Marc

    2010-01-01

    The mammalian auditory organ, the organ of Corti (OC), is composed of mechanosensory hair cells and nonsensory supporting cell types. Based on their morphology and physiology, at least two types of sensory cells can be identified in the OC: inner and outer hair cells. The structure of this organ is well reported in adult but its development is still little-known. By using confocal microscopy, we studied the spatial-temporal distribution of beta tubulin III during the differentiation of th...

  6. Asymmetric threat data mining and knowledge discovery

    Science.gov (United States)

    Gilmore, John F.; Pagels, Michael A.; Palk, Justin

    2001-03-01

    Asymmetric threats differ from the conventional force-on- force military encounters that the Defense Department has historically been trained to engage. Terrorism by its nature is now an operational activity that is neither easily detected or countered as its very existence depends on small covert attacks exploiting the element of surprise. But terrorism does have defined forms, motivations, tactics and organizational structure. Exploiting a terrorism taxonomy provides the opportunity to discover and assess knowledge of terrorist operations. This paper describes the Asymmetric Threat Terrorist Assessment, Countering, and Knowledge (ATTACK) system. ATTACK has been developed to (a) data mine open source intelligence (OSINT) information from web-based newspaper sources, video news web casts, and actual terrorist web sites, (b) evaluate this information against a terrorism taxonomy, (c) exploit country/region specific social, economic, political, and religious knowledge, and (d) discover and predict potential terrorist activities and association links. Details of the asymmetric threat structure and the ATTACK system architecture are presented with results of an actual terrorist data mining and knowledge discovery test case shown.

  7. Vínculo materno-fetal: implicaciones en el desarrollo psicológico y propuesta de intervención en atención temprana (Maternal-foetal bonding: implications for psychological development and proposal for early intervention

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Roncallo

    2015-09-01

    Full Text Available Health research has identified maternal-foetal bonding as a significant antecedent of post-natal bonding between mother and baby. Maternal-foetal bonding is associated with the emotional and cognitive aspects that allow the foetus to be recreated as another human being. This bond is expressed in health practices aimed at the protection and welfare of the foetus. It has been observed that the psychological state of the mother affects the foetus at the neurobehavioral level and influences the appearance of developmental disorders that also manifest in the post-natal period, thereby significantly affecting the mother-baby relationship. Thus, early intervention practices could be extended to the prenatal period as a prevention strategy to favourably impact the health of the child and mother. To address this issue, we present an interdisciplinary intervention model, which focuses on maternal-foetal bonding as a protective factor for bonding during the postnatal period, and as an enhancer of positive parenting practices that promote healthy psychological development.

  8. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  9. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul;

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b......A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines...

  10. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  11. Incompressibility of asymmetric nuclear matter

    OpenAIRE

    Chen, Lie-Wen; Cai, Bao-Jun; Shen, Chun; Ko, Che Ming; Xu, Jun; Li, Bao-An(Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, TX, 75429-3011, USA)

    2009-01-01

    The incompressibility $K_sat(\\delta)$ of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of $K_sat(\\delta)$ in powers of isospin asymmetry $\\delta$, i.e., $K_sat(\\delta )$=K_{0}+K_{sat,2}\\delta^{2}+K_{sat,4}\\delta^{4}+O(\\delta^{6})$, the magnitude of the 4th-order K_{sat,4} parameter is generally small. The 2nd-order K_{sat,2} parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matte...

  12. Forces between asymmetric polymer brushes

    OpenAIRE

    Shim, D.F.K.; Cates, M. E.

    1990-01-01

    We study the equilibrium compression of asymmetric polymer brushes grafted on flat plates, under athermal and theta solvent conditions, using a lattice self-consistent field (SCF) approach. We find that the separation d between two plates coated asymmetrically with brushes of type 1 and 2, as a function of the force F, obeys the "bisection rule", d(F) = (d1(F) + d 2(F)) /2 where d1(F)and d 2(F) are the corresponding separations for the symmetric brushes of type 1 and 2 respectively.The bisect...

  13. Research on asymmetric "Jerusalem" unit

    Institute of Scientific and Technical Information of China (English)

    Jun Lu; Jianbo Wang

    2009-01-01

    An asymmetric Jerusalem unit and the frequency selective surface(FSS)structure composed of such units are designed.The transmittance of the designed FSS structure is calculated by mode-matching method and compared with the test results.The comparison results show that the FSS center frequency of the asymmetric structure unit drifts little with the variation of the incident angles of the electromagnetic waves and keeps relatively stable.The research offers a new choice for the application of FSS under the large scanning angle of electromagnetic waves.

  14. Investigation of Asymmetric Thrust Detection with Demonstration in a Real-Time Simulation Testbed

    Science.gov (United States)

    Chicatelli, Amy K.; Rinehart, Aidan W.; Sowers, T. Shane; Simon, Donald L.

    2016-01-01

    The purpose of this effort is to develop, demonstrate, and evaluate three asymmetric thrust detection approaches to aid in the reduction of asymmetric thrust-induced aviation accidents. This paper presents the results from that effort and their evaluation in simulation studies, including those from a real-time flight simulation testbed. Asymmetric thrust is recognized as a contributing factor in several Propulsion System Malfunction plus Inappropriate Crew Response (PSM+ICR) aviation accidents. As an improvement over the state-of-the-art, providing annunciation of asymmetric thrust to alert the crew may hold safety benefits. For this, the reliable detection and confirmation of asymmetric thrust conditions is required. For this work, three asymmetric thrust detection methods are presented along with their results obtained through simulation studies. Representative asymmetric thrust conditions are modeled in simulation based on failure scenarios similar to those reported in aviation incident and accident descriptions. These simulated asymmetric thrust scenarios, combined with actual aircraft operational flight data, are then used to conduct a sensitivity study regarding the detection capabilities of the three methods. Additional evaluation results are presented based on pilot-in-the-loop simulation studies conducted in the NASA Glenn Research Center (GRC) flight simulation testbed. Data obtained from this flight simulation facility are used to further evaluate the effectiveness and accuracy of the asymmetric thrust detection approaches. Generally, the asymmetric thrust conditions are correctly detected and confirmed.

  15. Synthesis of Asymmetric Propanetriol Analogues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From natural tartaric acid, (R)-2-benzyloxy-3-(2-tetrahydropyranyloxy) propanol 3 was designed and synthesized, and (R)-2-benzyloxy-3-(4-methoxybenzyloxy) propanol 7 was prepared in a new method. They can be used as chiral synthons of lysophosphatidic acid and other compounds with asymmetric propanetriol backbone.

  16. Vertical asymmetric double quantum dots

    Science.gov (United States)

    Roßbach, R.; Reischle, M.; Beirne, G. J.; Schweizer, H.; Jetter, M.; Michler, P.

    2007-01-01

    Two layers of differently sized self-assembled InP-quantum dots (QDs) separated by a GaInP spacer layer with varying thickness were grown by metal organic vapor phase epitaxy (MOVPE). Photoluminescence measurements of the QD ensembles and of individual asymmetric double QDS show coupling due to the tunnelling of carriers.

  17. Asymmetrical Switch Costs in Children

    Science.gov (United States)

    Ellefson, Michelle R.; Shapiron, Laura R.; Chater, Nick

    2006-01-01

    Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about…

  18. Recent advances in catalytic asymmetric hydrogenation:Renaissance of the monodentate phosphorus ligands

    Institute of Scientific and Technical Information of China (English)

    GUO Hongchao; DING Kuiling; DAI Lixin

    2004-01-01

    The history for the development of chiral phosphorus ligands in catalytic asymmetric hydrogenation is briefly highlighted. This review focuses on the recent advances in the synthesis of the monodentate phosphorus ligands and their applications in catalytic asymmetric hydrogenation. The examples highlighted in this article clearly demonstrated the importance and advantages of monodentate phosphorus ligands, which had been ignored for 30 a and experienced a renaissance at the very beginning of this millennium, particularly in the area of asymmetric hydrogenation.

  19. Extrahepatic biliary atresia with choledochal cyst: Prenatal MRI predicted and post natally confirmed: A case report

    Directory of Open Access Journals (Sweden)

    Madhavi Nori

    2013-01-01

    Full Text Available Extrahepatic biliary atresia (EHBA is an uncommon cause of neonatal jaundice. Antenatal Magnetic Resonance Imaging (MRI diagnosis of EHBA has not been published to the best of our knowledge till date. EHBA with cystic component is likely to be mistaken for choledochal cyst. A case that was antenatally predicted and postnatally confirmed by surgery and histopathology is being reported. All imaging signs are analyzed herewith. Imaging helps in the prediction of EHBA and also helps in early postnatal surgical referral which in turn improves the results of Kasai′s portoenterostomy.

  20. PORENCEPHALY AS A RESULT OF PARENENYMATOUS HAEMORRHAGE - PRENATAL AND POST NATAL IMAGIOLOGY

    OpenAIRE

    Cunha, A.; Mendes, M; Ramos, C.; R. Nogueira; M. Martins; Veloso, P.; Mendes, R.

    2004-01-01

    RESUMO A infecção por Citomegalovírus (CMV) é a infecçâo congénita mais frequente. As manifestações clínicas são variáveis e multisistémicas. Do envolvimento do sistema nervoso central (SNC) podem resultar microcefalia, calcificações e, mais raramente, hidranencefalia e porencefalia por destruição do tecido cerebral. Estes achados são geralmente de diagnóstico tardio em Diagnóstico Pré Natal (DPN) com manifestações ecográficas muitas vezes inespecíficas. ...

  1. Maternal post natal hospital readmission-trends and association with mode of delivery.

    LENUS (Irish Health Repository)

    Ade-Conde, J A

    2012-02-01

    The aim of this study is to examine the trend in maternal postnatal readmission within six weeks of discharge from childbirth hospitalisation. It is a retrospective review of the maternity computer records system, patient\\'s clinical notes and HIPE data base. All women who delivered babies weighing > 500 g and\\/ > or = 24 weeks gestational age at Our Lady of Lourdes Hospital, Drogheda, Ireland from 1st January 2005 to 31st December 2008 who were re-hospitalised within six weeks of discharge from hospital following child birth were included in the study. A total of 15782 women were delivered over the four year study period. Of these, 236 were readmitted. A series of chi-square analysis were conducted to assess the difference in readmission rates between the year 2008 86 (2.03%) and the years 2005-51(1.46%), 2006-39 (1.01%) and 2007-60 (1.42%). The readmission rate was found to be significantly higher in 2008 compared with the three preceding years. Complications of Caesarean section and secondary postpartum haemorrhage following spontaneous vaginal delivery constitute the major indications for readmission.

  2. Extrahepatic biliary atresia with choledochal cyst: Prenatal MRI predicted and post natally confirmed: A case report.

    Science.gov (United States)

    Nori, Madhavi; Venkateshwarlu, J; Vijaysekhar; Prasad, G Raghavendra

    2013-07-01

    Extrahepatic biliary atresia (EHBA) is an uncommon cause of neonatal jaundice. Antenatal Magnetic Resonance Imaging (MRI) diagnosis of EHBA has not been published to the best of our knowledge till date. EHBA with cystic component is likely to be mistaken for choledochal cyst. A case that was antenatally predicted and postnatally confirmed by surgery and histopathology is being reported. All imaging signs are analyzed herewith. Imaging helps in the prediction of EHBA and also helps in early postnatal surgical referral which in turn improves the results of Kasai's portoenterostomy. PMID:24347854

  3. Extrahepatic biliary atresia with choledochal cyst: Prenatal MRI predicted and post natally confirmed: A case report

    OpenAIRE

    Madhavi Nori; J Venkateshwarlu; Vijaysekhar,; Raghavendra Prasad, G.

    2013-01-01

    Extrahepatic biliary atresia (EHBA) is an uncommon cause of neonatal jaundice. Antenatal Magnetic Resonance Imaging (MRI) diagnosis of EHBA has not been published to the best of our knowledge till date. EHBA with cystic component is likely to be mistaken for choledochal cyst. A case that was antenatally predicted and postnatally confirmed by surgery and histopathology is being reported. All imaging signs are analyzed herewith. Imaging helps in the prediction of EHBA and also helps in early po...

  4. Pre- and post-natal exposure of children to EMF generated by domestic induction cookers

    Energy Technology Data Exchange (ETDEWEB)

    Kos, Bor; Miklavcic, Damijan; Kotnik, Tadej [Laboratory of Biocybernetics, Faculty of Electrical Engineering, University of Ljubljana, Trzaska 25, SI-1000 Ljubljana (Slovenia); Valic, Blaz; Gajsek, Peter, E-mail: bor.kos@fe.uni-lj.si, E-mail: damijan.miklavcic@fe.uni-lj.si, E-mail: tadej.kotnik@fe.uni-lj.si, E-mail: blaz.valic@inis.si, E-mail: p.gajsek@inis.si [Institute of Non-Ionizing Radiation, Pohorskega Bataljona 215, SI-1000 Ljubljana (Slovenia)

    2011-10-07

    Induction cookers are a type of cooking appliance that uses an intermediate-frequency magnetic field to heat the cooking vessel. The magnetic flux density produced by an induction cooker during operation was measured according to the EN 62233 standard, and the measured values were below the limits set in the standard. The measurements were used to validate a numerical model consisting of three vertically displaced coaxial current loops at 35 kHz. The numerical model was then used to compute the electric field (E) and induced current (J) in 26 and 30 weeks pregnant women and 6 and 11 year old children. Both E and J were found to be below the basic restrictions of the 2010 low-frequency and 1998 ICNRIP guidelines. The maximum computed E fields in the whole body were 0.11 and 0.66 V m{sup -1} in the 26 and 30 weeks pregnant women and 0.28 and 2.28 V m{sup -1} in the 6 and 11 year old children (ICNIRP basic restriction 4.25 V m{sup -1}). The maximum computed J fields in the whole body were 46 and 42 mA m{sup -2} in the 26 and 30 weeks pregnant women and 27 and 16 mA m{sup -2} in the 6 and 11 year old children (ICNIRP basic restriction 70 mA m{sup -2}).

  5. Pre- and post-natal exposure of children to EMF generated by domestic induction cookers

    Science.gov (United States)

    Kos, Bor; Valič, Blaž; Miklavčič, Damijan; Kotnik, Tadej; Gajšek, Peter

    2011-10-01

    Induction cookers are a type of cooking appliance that uses an intermediate-frequency magnetic field to heat the cooking vessel. The magnetic flux density produced by an induction cooker during operation was measured according to the EN 62233 standard, and the measured values were below the limits set in the standard. The measurements were used to validate a numerical model consisting of three vertically displaced coaxial current loops at 35 kHz. The numerical model was then used to compute the electric field (E) and induced current (J) in 26 and 30 weeks pregnant women and 6 and 11 year old children. Both E and J were found to be below the basic restrictions of the 2010 low-frequency and 1998 ICNRIP guidelines. The maximum computed E fields in the whole body were 0.11 and 0.66 V m-1 in the 26 and 30 weeks pregnant women and 0.28 and 2.28 V m-1 in the 6 and 11 year old children (ICNIRP basic restriction 4.25 V m-1). The maximum computed J fields in the whole body were 46 and 42 mA m-2 in the 26 and 30 weeks pregnant women and 27 and 16 mA m-2 in the 6 and 11 year old children (ICNIRP basic restriction 70 mA m-2).

  6. Selfhealing of asymmetric Bessel-like modes

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller; Rishøj, Lars Søgaard; Rottwitt, Karsten

    2014-01-01

    We numerically investigate asymmetric Bessel-like modes in an aircladding fiber. The selfhealing ability of asymmetric Bessel-like modes is demonstrated and quantified including the angular dependency of this ability.......We numerically investigate asymmetric Bessel-like modes in an aircladding fiber. The selfhealing ability of asymmetric Bessel-like modes is demonstrated and quantified including the angular dependency of this ability....

  7. Analysis of Asymmetric Piezoelectric Composite Beam

    CERN Document Server

    Chen, J -S; Wu, K -C

    2008-01-01

    This paper deals with the vibration analysis of an asymmetric composite beam composed of glass a piezoelectric material. The Bernoulli's beam theory is adopted for mechanical deformations, and the electric potential field of the piezoelectric material is assumed such that the divergence-free requirement of the electrical displacements is satisfied. The accuracy of the analytic model is assessed by comparing the resonance frequencies obtained by the analytic model with those obtained by the finite element method. The model developed can be used as a tool for designing piezoelectric actuators such as micro-pumps.

  8. Long-lived oscillons from asymmetric bubbles

    CERN Document Server

    Adib, A B; Almeida, C A S; Adib, Artur B.; Gleiser, Marcelo; Almeida, Carlos A. S.

    2002-01-01

    The possibility that extremely long-lived, time-dependent, and localized field configurations (``oscillons'') arise during the collapse of asymmetrical bubbles in 2+1 dimensional \\phi^4 models is investigated. It is found that oscillons can develop from a large spectrum of elliptically deformed bubbles. Moreover, it is found that such oscillons are: a) circularly symmetric; and b) stable against small arbitrary radial and angular perturbations. They may thus play an important role in the study of time-dependent nonperturbative configurations in field theory, with applications ranging from nonequilibrium statistical physics to early universe cosmology.

  9. Neuronal Alignment On Asymmetric Textured Surfaces

    CERN Document Server

    Beighley, Ross; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C; Staii, Cristian

    2013-01-01

    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify the role that biomechanical surface cues play in neuronal growth. These results represent an important step towards engineering directed axonal growth for neuro-regeneration studies.

  10. Iron-, Cobalt-, and Nickel-Catalyzed Asymmetric Transfer Hydrogenation and Asymmetric Hydrogenation of Ketones.

    Science.gov (United States)

    Li, Yan-Yun; Yu, Shen-Luan; Shen, Wei-Yi; Gao, Jing-Xing

    2015-09-15

    Chiral alcohols are important building blocks in the pharmaceutical and fine chemical industries. The enantioselective reduction of prochiral ketones catalyzed by transition metal complexes, especially asymmetric transfer hydrogenation (ATH) and asymmetric hydrogenation (AH), is one of the most efficient and practical methods for producing chiral alcohols. In both academic laboratories and industrial operations, catalysts based on noble metals such as ruthenium, rhodium, and iridium dominated the asymmetric reduction of ketones. However, the limited availability, high price, and toxicity of these critical metals demand their replacement with abundant, nonprecious, and biocommon metals. In this respect, the reactions catalyzed by first-row transition metals, which are more abundant and benign, have attracted more and more attention. As one of the most abundant metals on earth, iron is inexpensive, environmentally benign, and of low toxicity, and as such it is a fascinating alternative to the precious metals for catalysis and sustainable chemical manufacturing. However, iron catalysts have been undeveloped compared to other transition metals. Compared with the examples of iron-catalyzed asymmetric reduction, cobalt- and nickel-catalyzed ATH and AH of ketones are even seldom reported. In early 2004, we reported the first ATH of ketones with catalysts generated in situ from iron cluster complex and chiral PNNP ligand. Since then, we have devoted ourselves to the development of ATH and AH of ketones with iron, cobalt, and nickel catalysts containing novel chiral aminophosphine ligands. In our study, the iron catalyst containing chiral aminophosphine ligands, which are expected to control the stereochemistry at the metal atom, restrict the number of possible diastereoisomers, and effectively transfer chiral information, are successful catalysts for enantioselective reduction of ketones. Among these novel chiral aminophosphine ligands, 22-membered macrocycle P2N4

  11. ASYMMETRIC VORTICES FLOW OVER SLENDER BODY AND ITS ACTIVE CONTROL AT HIGH ANGLE OF ATTACK

    Institute of Scientific and Technical Information of China (English)

    DENG Xueying; WANG Yankui

    2004-01-01

    The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area. This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices. This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices. The critical issues are discussed,which include the formation and evolution mechanism of asymmetric multi-vortices; main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure; the evolution and development of asymmetric vortices under the perturbation on the model nose; forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail. However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks.

  12. Long non-coding RNA expression profiling of mouse testis during postnatal development.

    Directory of Open Access Journals (Sweden)

    Jin Sun

    Full Text Available Mammalian testis development and spermatogenesis play critical roles in male fertility and continuation of a species. Previous research into the molecular mechanisms of testis development and spermatogenesis has largely focused on the role of protein-coding genes and small non-coding RNAs, such as microRNAs and piRNAs. Recently, it has become apparent that large numbers of long (>200 nt non-coding RNAs (lncRNAs are transcribed from mammalian genomes and that lncRNAs perform important regulatory functions in various developmental processes. However, the expression of lncRNAs and their biological functions in post-natal testis development remain unknown. In this study, we employed microarray technology to examine lncRNA expression profiles of neonatal (6-day-old and adult (8-week-old mouse testes. We found that 8,265 lncRNAs were expressed above background levels during post-natal testis development, of which 3,025 were differentially expressed. Candidate lncRNAs were identified for further characterization by an integrated examination of genomic context, gene ontology (GO enrichment of their associated protein-coding genes, promoter analysis for epigenetic modification, and evolutionary conservation of elements. Many lncRNAs overlapped or were adjacent to key transcription factors and other genes involved in spermatogenesis, such as Ovol1, Ovol2, Lhx1, Sox3, Sox9, Plzf, c-Kit, Wt1, Sycp2, Prm1 and Prm2. Most differentially expressed lncRNAs exhibited epigenetic modification marks similar to protein-coding genes and tend to be expressed in a tissue-specific manner. In addition, the majority of differentially expressed lncRNAs harbored evolutionary conserved elements. Taken together, our findings represent the first systematic investigation of lncRNA expression in the mammalian testis and provide a solid foundation for further research into the molecular mechanisms of lncRNAs function in mammalian testis development and spermatogenesis.

  13. Asymmetric Multilevel Diversity Coding and Asymmetric Gaussian Multiple Descriptions

    CERN Document Server

    Mohajer, Soheil; Diggavi, Suhas N

    2009-01-01

    We consider the asymmetric multilevel diversity (A-MLD) coding problem, where a set of $2^K-1$ information sources, ordered in a decreasing level of importance, is encoded into $K$ messages (or descriptions). There are $2^K-1$ decoders, each of which has access to a non-empty subset of the encoded messages. Each decoder is required to reproduce the information sources up to a certain importance level depending on the combination of descriptions available to it. We obtain a single letter characterization of the achievable rate region for the 3-description problem. In contrast to symmetric multilevel diversity coding, source-separation coding is not sufficient in the asymmetric case, and ideas akin to network coding need to be used strategically. Based on the intuitions gained in treating the A-MLD problem, we derive inner and outer bounds for the rate region of the asymmetric Gaussian multiple description (MD) problem with three descriptions. Both the inner and outer bounds have a similar geometric structure t...

  14. Modelling asymmetric growth in crowded plant communities

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2010-01-01

    A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size-asymmetric ......A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size...

  15. Asymmetric information and macroeconomic dynamics

    Science.gov (United States)

    Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

    2010-09-01

    We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

  16. Entrepreneurship, Asymmetric Information and Unemployment

    OpenAIRE

    Robin Boadway; Nicolas Marceau; Maurice Marchand; Marianne Vigneault

    1998-01-01

    We examine how three sources of asymmetric information affect the supply of entrepreneurs and unemployment. In the first case, banks cannot observe entrepreneurs' risk of failure so ration credit. This increases the number of entrepreneurs and the level of unemployment. In the second case, firms cannot observe workers' effort so offer a wage above the market clearing one. This results in unemployment and too few entrepreneurs. The final case arises when firms cannot observe workers' abilities...

  17. Asymmetric Wettability Directs Leidenfrost Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, Rebecca L [ORNL; Boreyko, Jonathan B [ORNL; Briggs, Dayrl P [ORNL; Srijanto, Bernadeta R [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL; Lavrik, Nickolay V [ORNL

    2014-01-01

    Leidenfrost phenomena on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems utilizing boiling phenomena. They also provide an elegant means to direct droplet motion in a variety of recently emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions, namely on impact with Weber numbers 40 at T 325 C. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask, with mean pillar diameters of 100 nm and heights of 200-500 nm. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling, suggesting that the observed droplet directionality is not a result of asymmetric vapor flow. Using high-speed imaging, phase diagrams were constructed for the boiling behavior upon impact for droplets falling onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. The asymmetric impact and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing that asymmetric wettability upon impact is the mechanism for the droplet directionality.

  18. Timing of motor milestones achievement and development of overweight in childhood

    DEFF Research Database (Denmark)

    Morgen, Camilla Schmidt; Andersen, Anne-Marie Nybo; Due, P;

    2014-01-01

    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The risk of childhood obesity is influenced by a number of pre- and post-natal factors. The risk of childhood obesity is correlated with body weight during infancy, which might be related to the psychomotor development of the child. The previous literature...... on motor milestones and childhood overweight is limited and results are inconsistent. WHAT THIS STUDY ADDS: Weight status in early life and timing of achievement of gross motor milestones (the ability to sit and walk) are largely independent of each other. Timing of achievement of motor milestones in early...... life does not predict overweight or increased BMI later in childhood. BACKGROUND: Overweight may hinder achievement of gross motor milestones and delayed achievement of milestones may increase the risk of later overweight for reasons involving physical activity and the building of lean body mass...

  19. Asymmetric condensed dark matter

    Science.gov (United States)

    Aguirre, Anthony; Diez-Tejedor, Alberto

    2016-04-01

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

  20. Success Factors of Asymmetric Connections - Example of Large Slovenian Enterprises

    Directory of Open Access Journals (Sweden)

    Viktor Vračar

    2014-11-01

    Full Text Available More and more companies realize the fact that networking or partner collaborations, which are based on partner relations between companies, are essential for their long-term existence. In today’s global competitive environment each company is included at least in some different connections. Very common connections occur between large and smaller enterprises, where the so called asymmetric connections occur, which may be understood as the ability of one organisation to establish power, influence and control over the other organisation and its resources. According to numerous statements, the connections between enterprises are very frequently uneffectivenessful, with opinions on the optimal nature of asymmetric connections being quite common as well, whereby it is, as a rule, a synergic complementing of missing content for both partners. To verify the thesis, that companies achieve more competitiveness and effectiveness through connections, whereby the so called asymmetric connections are common, a structural model of the evolution of asymmetric connection has been developed, which connects the theoretically identified factors and all dependent concepts of competitiveness, efficiency and effectiveness. The empirical research also attempts to further expose the factors of asymmetric connections, which affect efficiency and effectiveness of the connected enterprises.

  1. The Development of Chiral Catalysis in Asymmetric Synthesis%手性催化在不对称合成中的发展

    Institute of Scientific and Technical Information of China (English)

    杨晓刚; 黄蓓

    2012-01-01

    介绍了手性化合物的重要性及其发展情况,从手性分子的制备、手性有机小分子催化的应用等方面总结了手性分子的研究进展,指出了手性分子的发展方向。%The importance and devopment of chiral compounds are introduced, from the preparation of chiral molecule, the application of chiral organic small molecular catalyst, the research progress of chiral molealle are summarized, the development direction of chiral molecule are pointed out.

  2. Asymmetric oro-facial angioedema following alteplase for acute ischaemic stroke.

    Science.gov (United States)

    Wu, Teddy Y; Wei, Diana Y; Baker, Yvette; Sharkey, Brendan; Frith, Richard W

    2014-11-01

    We present a patient with asymmetric oro-facial angioedema following thrombolysis for acute ischaemic stroke with serial photographs of this phenomenon. We discuss the mechanism for the development of asymmetric oro-facial oedema following thrombolysis and suggest a management plan. PMID:24974191

  3. A new method of asymmetric Abel inversion for magnetic equilibrium configuration state in tokamaks

    Institute of Scientific and Technical Information of China (English)

    Tian Chong-Li; Zhou Yan; Shi Zhong-Bing; Li Ying-Liang

    2007-01-01

    It is difficult to obtain the asymmetrical factor along the observation direction parallel to the plasma mid-plane when the detected radiation is also in the mid-plane. This paper considers the magnetic surfaces and Grad-Shafranov shift, and develops a new method for inverse asymmetric electron density information, during magnetic equilibrium configuration in a tokamak.

  4. Gravity-induced asymmetric distribution of a plant growth hormone

    Science.gov (United States)

    Bandurski, R. S.; Schulze, A.; Momonoki, Y.

    1984-01-01

    Dolk (1936) demonstrated that gravistimulation induced an asymmetric distribution of auxin in a horizontally-placed shoot. An attempt is made to determine where and how that asymmetry arises, and to demonstrate that the endogenous auxin, indole-3-acetic acid, becomes asymmetrically distributed in the cortical cells of the Zea mays mesocotyl during 3 min of geostimulation. Further, indole-3-acetic acid derived by hydrolysis of an applied transport form of the hormone, indole-3-acetyl-myo-inositol, becomes asymmetrically distributed within 15 min of geostimulus time. From these and prior data is developed a working theory that the gravitational stimulus induces a selective leakage, or secretion, of the hormone from the vascular tissue to the cortical cells of the mesocotyl.

  5. Data analysis of asymmetric structures advanced approaches in computational statistics

    CERN Document Server

    Saito, Takayuki

    2004-01-01

    Data Analysis of Asymmetric Structures provides a comprehensive presentation of a variety of models and theories for the analysis of asymmetry and its applications and provides a wealth of new approaches in every section. It meets both the practical and theoretical needs of research professionals across a wide range of disciplines and  considers data analysis in fields such as psychology, sociology, social science, ecology, and marketing. In seven comprehensive chapters this guide details theories, methods, and models for the analysis of asymmetric structures in a variety of disciplines and presents future opportunities and challenges affecting research developments and business applications.

  6. Preview-based Asymmetric Load Reduction of Wind Turbines

    DEFF Research Database (Denmark)

    Madsen, Mathias; Filsø, Jakob; Soltani, Mohsen

    2012-01-01

    Fatigue loads on wind turbines caused by an asymmetric wind field become an increasing concern when the scale of wind turbines increases. This paper presents a model based predictive approach to reduce asymmetric loads by using Light Detection And Ranging (LIDAR) measurements. The Model Predictive...... Controller (MPC) developed is based on a model with individual blade pitching to utilize the LIDAR measurements. The MPC must also maintain a given power reference while satisfying a set of actuator constraints. The designed controller was tested on a 5 MW wind turbine in the FAST simulator and compared...

  7. Effect of stress hormone antagonists on ovarian follicular development in pre-pubertal rat

    Directory of Open Access Journals (Sweden)

    Kalid Hamood Abdullah

    2012-08-01

    Full Text Available Effect of stress on pre-pubertal ovarian follicular development was studied. Fifteen day old female rats were administered under stress (exposed to maternal separation; 6 hours/day from post-natal day 15 to 21 for 7 days, and appropriate controls were maintained. The time of exposure was randomly changed every day during light phase (7AM to 7 PM of the day to avoid habituation. There was a significant decrease in serum estrogen levels on post-natal day 21 in stress group rats compared to controls indicating stress response in these rats. However, mean number of healthy follicles in all categories of follicles were significantly lower in stressed rats compared to controls. Concomitant with these changes, mean number of atreitic follicles showed an increase over control values in stressed rats. In contrast administration of Naltrexone (5μg NTX/rat/day, Mifepristone (1 μg MP/rat/day, FSH (10 IU FSH/rat/day with stressed the significant increases in the relative weight of ovary, uterus, fallopian tube, body weight and the mean number of healthy follicles in the ovary compared to the controls. In the ovary treatment of stressed did not affect primordial follicles. Primordial follicles were reduced in number significantly in the ovary of controls and treated groups when compared with the initial controls whereas there was no significant variation among the controls and the treated groups. The results indicate that stress dose not interfere with the progress of pre-pubertal follicular development. However, it causes increased loss of follicles by atretia.

  8. Instability of asymmetric continuous shaft system

    Science.gov (United States)

    Srinath, R.; Sarkar, Abhijit; Sekhar, A. S.

    2016-11-01

    In this work, the governing equation of asymmetric continuous shaft in inertial frame of reference is studied. In particular, determination of the parameter ranges for the stability or instability of the shaft response is the focus of the present work. The governing equations are a fourth-order coupled partial differential equations containing time dependent coefficients. The equations are non-dimensionalized in terms of two parameters related to the average moment of inertia and the difference of moments of inertia about the principal axes. Using the latter as the asymptotic parameter and employing modal superposition, a formal methodology based on perturbation methods is developed to ascertain the stability and instability characteristics. The methodology is applicable to shafts subjected to some of the classical boundary conditions viz. simply supported, cantilever, and fixed-fixed. Similar stability curves are obtained for each mode for these different boundary conditions. The novel non-dimensionalization scheme chosen leads to the stability boundaries as well as the loci of varying speeds to be in the form of straight lines. The intersection of these lines determine the stable and unstable speed ranges of different asymmetric shafts. The results are generalized for different material and geometric properties of the shaft.

  9. Welfare-Improving Asymmetric Information in Dynamic Insurance Markets.

    Science.gov (United States)

    de Garidel-Thoron, Thomas

    2005-01-01

    This article presents a two-period asymmetric learning model of insurance markets. When information about past accidents is not shared by insurers, asymmetries of information develop through time. Equilibrium contracts exist, are payoff unique, and display a realistic bonus-malus pattern. Eliminating asymmetries through information sharing is…

  10. Loss aversion and the asymmetric transmission of monetary policy

    NARCIS (Netherlands)

    Gaffeo, E.; Petrella, I.; Pfajfar, D.; Santoro, E.

    2014-01-01

    There is widespread evidence that monetary policy exerts asymmetric effects on output over contractions and expansions in economic activity, while price responses display no sizeable asymmetry. To rationalize these facts we develop a dynamic general equilibrium model where households’ utility depend

  11. Physics of asymmetric continuum earthquake rotation and soliton waves

    CERN Document Server

    Teisseyre, Roman; Majewski, Eugeniusz

    2008-01-01

    This book gives an overview of some fundamental theories of continua, in particular those with defect content. In addition, it develops asymmetric theory of continuum, which includes such correlated solutions that had not been anticipated in the previous theories of continua.

  12. Development of Asymmetric Hydrogenation Catalysts via High Throughput Experimentation Développement de catalyseurs d’hydrogénation asymétrique par criblage haut débit

    Directory of Open Access Journals (Sweden)

    de Vries J. G.

    2013-02-01

    Full Text Available The dynamics of drugs discovery imposes severe time constraints on the development chemist in charge of implementing the large scale production of a new Active Pharmaceutical Ingredient (API. This results in the use of well-established and robust transformations at the expense of the cost-efficiency and the sustainability of the process. In order to cope with the short development time and allow the implementation of new more efficient production technologies such as asymmetric hydrogenation, we have turned towards the use of high throughput experimentation for the discovery of new catalysts. The protocol for the preparation of a library of chiral ligands and its application to real-life pharmaceutical molecules is described in this article. La découverte de nouvelles molécules pharmaceutiques a sa propre dynamique qui impose des contraintes temporelles très strictes au chimiste en charge de développer la production du principe actif à large échelle. En conséquence, ce dernier va se tourner vers l’utilisation de technologies éprouvées et robustes quitte à rendre le procédé plus coûteux ou plus polluant. Afin de pouvoir faire face à des temps de développement très courts et d’introduire en production des technologies modernes et non polluantes comme l’hydrogénation asymétrique, nous avons développé une plateforme de criblage haut débit pour la découverte de nouveaux catalyseurs. Dans cet article, nous décrivons une des facettes de cette plateforme qui est la synthèse de librairies de ligands chiraux et leur application au cas réel d’une molécule pharmaceutique.

  13. Asymmetric Information and Consumer Demand

    OpenAIRE

    Ismagilova G. N.; Danilina E. I.; Gafurov I. R.; Ismagilov R. I.; Safiullin L. N.

    2014-01-01

    In the paper study the peculiarities of the formation the consumer demand for durable goods, the so-called «experience goods» in markets with asymmetric information. In the known literature sources studying of the demand is based on the assumption that at the moment of the purchase of goods and services people know exactly what price they are willing to pay for them and what utility they are going to obtain using those goods and services. Consider the signal model in which the initial price a...

  14. Spontaneous baryogenesis from asymmetric inflaton

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)

    2015-10-15

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  15. Asymmetric Formal Synthesis of Azadirachtin.

    Science.gov (United States)

    Mori, Naoki; Kitahara, Takeshi; Mori, Kenji; Watanabe, Hidenori

    2015-12-01

    An asymmetric formal synthesis of azadirachtin, a potent insect antifeedant, was accomplished in 30 steps to Ley's synthetic intermediate (longest linear sequence). The synthesis features: 1) rapid access to the optically active right-hand segment starting from the known 5-hydroxymethyl-2-cyclopentenone scaffold; 2) construction of the B and E rings by a key intramolecular tandem radical cyclization; 3) formation of the hemiacetal moiety in the C ring through the α-oxidation of the six-membered lactone followed by methanolysis. PMID:26474211

  16. Transient Stability During Asymmetrical Faults

    OpenAIRE

    Couturier, Nicolas

    2015-01-01

    This research project has been conducted at RTE in order to study the transient stability after asymmetrical faults. When three-phase short-circuits occur in a network, almost all the electrical power is lost on the relevant line(s). Among all short-circuit types, it is the most drastic event and the issue has to be solved very quickly. But oddly, it is also the easiest problem to solve mathematically speaking. This comes from the fact that the system stays balanced, and equations can be simp...

  17. Enhanced Asymmetric Bilinear Model for Face Recognition

    OpenAIRE

    Wenjuan Gong; Weishan Zhang; Jordi Gonzàlez; Yan Ren; Zhen Li

    2015-01-01

    Bilinear models have been successfully applied to separate two factors, for example, pose variances and different identities in face recognition problems. Asymmetric model is a type of bilinear model which models a system in the most concise way. But seldom there are works exploring the applications of asymmetric bilinear model on face recognition problem with illumination changes. In this work, we propose enhanced asymmetric model for illumination-robust face recognition. Instead of initiali...

  18. Excitons in asymmetric quantum wells

    Science.gov (United States)

    Grigoryev, P. S.; Kurdyubov, A. S.; Kuznetsova, M. S.; Ignatiev, I. V.; Efimov, Yu. P.; Eliseev, S. A.; Petrov, V. V.; Lovtcius, V. A.; Shapochkin, P. Yu.

    2016-09-01

    Resonance dielectric response of excitons is studied for the high-quality InGaAs/GaAs heterostructures with wide asymmetric quantum wells (QWs). To highlight effects of the QW asymmetry, we have grown and studied several heterostructures with nominally square QWs as well as with triangle-like QWs. Several quantum confined exciton states are experimentally observed as narrow exciton resonances. A standard approach for the phenomenological analysis of the profiles is generalized by introducing different phase shifts for the light waves reflected from the QWs at different exciton resonances. Good agreement of the phenomenological fit to the experimentally observed exciton spectra for high-quality structures allowed us to reliably obtain parameters of the exciton resonances: the exciton transition energies, the radiative broadenings, and the phase shifts. A direct numerical solution of the Schrödinger equation for the heavy-hole excitons in asymmetric QWs is used for microscopic modeling of the exciton resonances. Remarkable agreement with the experiment is achieved when the effect of indium segregation is taken into account. The segregation results in a modification of the potential profile, in particular, in an asymmetry of the nominally square QWs.

  19. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  20. Asymmetric Wettability Directs Leidenfrost Droplets

    Science.gov (United States)

    Agapov, Rebecca; Boreyko, Jonathan; Briggs, Dayrl; Srijanto, Bernadeta; Retterer, Scott; Collier, C. Patrick; Lavrik, Nickolay

    2014-03-01

    Exploration of Leidenfrost droplets on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems using boiling phenomena. They also provide an elegant way to direct droplet motion in a variety of emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling. This suggests that the observed droplet directionality is not a result of asymmetric vapor flow. Phase diagrams were constructed for the boiling behavior upon droplet impact onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. Asymmetric wettability and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing this to be the mechanism for the droplet directionality. This work was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Lab by the Division of Scientific User Facilities, US Dept. of Energy.

  1. Some Remarks on Asymmetric Syntheses from Recent Studies

    OpenAIRE

    Baba, Naomichi

    1990-01-01

    Some asymmetric syntheses were presented here and discussed briefly including NADH model reactions, phase transfer-catalyzed asymmetric epoxidation, enantiotopic group-selective hydrolysis of a malonic anhydride with alkoxide anion, intramolecular acid-catalyzed lactonizations, catalytic asymmetric Diels-Alder synthesis, asymmetric aldol condensation, chiral homoallyl alcohol synthesis, asymmetric addition of diethylzinc to aldehyde, kinetic resolution of racemic hydroperoxides and binaphthol...

  2. Asymmetric Modeling of the Industrial Heavy Water Plant (PIAP)

    International Nuclear Information System (INIS)

    Software of asymmetric stationary simulation for the Industrial Heavy Water Plant (PIAP) was developed, based on an existing symmetric simulator (Brigitte 2.0).This software allows to turn off some of the isotopic enrichment twin units present in the plant and to simulate them asymmetrically, in other words, with different selection of parameters between twins.Other incorporations were done, such as passing flows between units and entering flows in strategic points of the plant.The iterative system in which the symmetric simulator is based was insufficient to develop the asymmetric simulator, so the system was modeled according to an implicit scheme for the units that form the simulator.This type of resolution resulted in a simulator that supports a big range of boundary conditions and internal parameters.Moreover, the time of calculus is short (∼3 minutes), making it actually useful.The asymmetric simulator is at the PIAP now, for its study and validation. It shows expected tendencies and results according to the symmetric simulator already validated

  3. The Asymmetric Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    We use the returns on lottery-like stocks to construct a novel index for investor sentiment in the stock market. This new measure is closely related to previously developed sentiment indicators, but more accurately tracks speculative episodes over the sample period. Using our index, we find...... that the relationship between sentiment and returns is asymmetric: during bear markets, high sentiment predicts low future returns for the cross-section of speculative stocks and the market overall while the relationship during bull markets is weak and often insignificant. Thus, the results suggest that sophisticated...... investors only act as corrective force during certain time periods. We also show that our index predicts implied volatility, media pessimism, and mutual fund flows. Overall, our findings are consistent with both the theories and anecdotal accounts of investor sentiment in the stock market....

  4. The Asymmetric Predictive Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    We use the returns on lottery-like stocks to construct a novel index for investor sentiment in the stock market. This new measure is closely related to previously developed sentiment indicators, but more accurately tracks speculative episodes over the sample period. Using our index, we find...... that the relationship between sentiment and returns is asymmetric: during bear markets, high sentiment predicts low future returns for the cross-section of speculative stocks and the market overall while the relationship during bull markets is weak and often insignicant. Thus, the results suggest that sophisticated...... investors only act as corrective force during certain time periods. We also show that our index predicts implied volatility, media pessimism, and mutual fund flows. Overall, our findings are consistent with both the theories and anecdotal accounts of investor sentiment in the stock market....

  5. Asymmetric correlations on the Croatian equity market

    Directory of Open Access Journals (Sweden)

    Davor Kunovac

    2011-03-01

    Full Text Available This paper compares the equity market in Croatia in bad (bear or turbulent and good (bull, calm market conditions. The two market regimes are formally identifi ed under the Markov Regime Switching (MRS framework. The analysis conducted suggests that correlations between equity prices are more than twice as high during bear than in bull markets. This result holds both for the shares included in the CROBEX and for the relationship among various European equity indices.In the context of international diversifi cation the result suggests only a limited benefi t that foreign investors can count on when diversifying their portfolios by expanding to developing European markets. In addition, by evaluating a portfolio optimization model that takes asymmetric correlations into account in an out-of-sample exercise, this paper also illustrates the losses that may occur if the asymmetry is ignored in practice.

  6. Neurons derive from the more apical daughter in asymmetric divisions in the zebrafish neural tube.

    Science.gov (United States)

    Alexandre, Paula; Reugels, Alexander M; Barker, David; Blanc, Eric; Clarke, Jonathan D W

    2010-06-01

    In the developing CNS, asymmetric cell division is critical for maintaining the balanced production of differentiating neurons while renewing the population of neural progenitors. In invertebrates, this process depends on asymmetric inheritance of fate determinants during progenitor divisions. A similar mechanism is widely believed to underlie asymmetrically fated divisions in vertebrates, but compelling evidence for this is missing. We used live imaging of individual progenitors in the intact zebrafish embryo CNS to test this hypothesis. We found that asymmetric inheritance of a subcellular domain is strongly correlated with asymmetric daughter fates and our results reveal an unexpected feature of this process. The daughter cell destined to become a neuron was derived from the more apical of the two daughters, whereas the more basal daughter inherited the basal process and replenished the apical progenitor pool.

  7. Tunable dual-band asymmetric transmission for circularly polarized waves with graphene planar chiral metasurfaces.

    Science.gov (United States)

    Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Chen, Shuqi; Tian, Jianguo

    2016-07-01

    The asymmetric transmission effect has attracted great interest due to its wide modern optical applications. In this Letter, we present the underlying theory, the design specifications, and the simulated demonstration of tunable dual-band asymmetric transmission for circularly polarized waves with a graphene planar chiral metasurface. The spectral position of the asymmetric peak is linearly dependent on the Fermi energy and can be controlled by changing the Fermi energy. The success of tunable dual-band asymmetric transmission can be attributed to the enantiomerically sensitive plasmonic excitations of the graphene metasurface. This work offers a further step in developing tunable asymmetric transmission of circularly polarized waves for applications in detectors and other polarization-sensitive electromagnetic devices. PMID:27367122

  8. Condensation on Slippery Asymmetric Bumps

    CERN Document Server

    Park, Kyoo-Chul; He, Neil; Aizenberg, Joanna

    2015-01-01

    Bumps are omnipresent from human skin to the geological structures on planets, which offer distinct advantages in numerous phenomena including structural color, drag reduction, and extreme wettability. Although the topographical parameters of bumps such as radius of curvature of convex regions significantly influence various phenomena including anti-reflective structures and contact time of impacting droplets, the effect of the detailed bump topography on growth and transport of condensates have not been clearly understood. Inspired by the millimetric bumps of the Namib Desert beetle, here we report the identified role of radius of curvature and width of bumps with homogeneous surface wettability in growth rate, coalescence and transport of water droplets. Further rational design of asymmetric convex topography and synergetic combination with slippery coating simultaneously enable self-transport, leading to unseen five-fold higher growth rate and an order of magnitude faster shedding time of droplets compared...

  9. New asymmetric quantum codes over Fq

    Science.gov (United States)

    Ma, Yuena; Feng, Xiaoyi; Xu, Gen

    2016-07-01

    Two families of new asymmetric quantum codes are constructed in this paper. The first family is the asymmetric quantum codes with length n=qm-1 over Fq, where qge 5 is a prime power. The second one is the asymmetric quantum codes with length n=3m-1. These asymmetric quantum codes are derived from the CSS construction and pairs of nested BCH codes. Moreover, let the defining set T1=T2^{-q}, then the real Z-distance of our asymmetric quantum codes are much larger than δ _max+1, where δ _max is the maximal designed distance of dual-containing narrow-sense BCH code, and the parameters presented here have better than the ones available in the literature.

  10. Quality Prediction of Asymmetrically Distorted Stereoscopic 3D Images.

    Science.gov (United States)

    Wang, Jiheng; Rehman, Abdul; Zeng, Kai; Wang, Shiqi; Wang, Zhou

    2015-11-01

    Objective quality assessment of distorted stereoscopic images is a challenging problem, especially when the distortions in the left and right views are asymmetric. Existing studies suggest that simply averaging the quality of the left and right views well predicts the quality of symmetrically distorted stereoscopic images, but generates substantial prediction bias when applied to asymmetrically distorted stereoscopic images. In this paper, we first build a database that contains both single-view and symmetrically and asymmetrically distorted stereoscopic images. We then carry out a subjective test, where we find that the quality prediction bias of the asymmetrically distorted images could lean toward opposite directions (overestimate or underestimate), depending on the distortion types and levels. Our subjective test also suggests that eye dominance effect does not have strong impact on the visual quality decisions of stereoscopic images. Furthermore, we develop an information content and divisive normalization-based pooling scheme that improves upon structural similarity in estimating the quality of single-view images. Finally, we propose a binocular rivalry-inspired multi-scale model to predict the quality of stereoscopic images from that of the single-view images. Our results show that the proposed model, without explicitly identifying image distortion types, successfully eliminates the prediction bias, leading to significantly improved quality prediction of the stereoscopic images. PMID:26087491

  11. Design of activated carbon/activated carbon asymmetric capacitors

    Directory of Open Access Journals (Sweden)

    Isabel ePiñeiro-Prado

    2016-03-01

    Full Text Available Supercapacitors are energy storage devices that offer a high power density and a low energy density in comparison with batteries. Their limited energy density can be overcome by using asymmetric configuration in mass electrodes, where each electrode works within their maximum available potential window, rendering the maximum voltage output of the system. Such asymmetric capacitors must be optimized through careful electrochemical characterization of the electrodes for accurate determination of the capacitance and the potential stability limits. The results of the characterization are then used for optimizing mass ratio of the electrodes from the balance of stored charge. The reliability of the design largely depends on the approach taken for the electrochemical characterization. Therefore, the performance could be lower than expected and even the system could break down, if a well thought out procedure is not followed.In this work, a procedure for the development of asymmetric supercapacitors based on activated carbons is detailed. Three activated carbon materials with different textural properties and surface chemistry have been systematically characterized in neutral aqueous electrolyte. The asymmetric configuration of the masses of both electrodes in the supercapacitor has allowed to cover a higher potential window, resulting in an increase of the energy density of the three devices studied when compared with the symmetric systems, and an improved cycle life.

  12. Asymmetric centrosome inheritance maintains neural progenitors in neocortex

    OpenAIRE

    Wang, Xiaoqun; Tsai, Jin-Wu; Imai, Janice H.; Lian, Wei-Nan; Vallee, Richard B.; Shi, Song-Hai

    2009-01-01

    Asymmetric divisions of radial glial progenitors produce self-renewing radial glia and differentiating cells simultaneously in the ventricular zone (VZ) of the developing neocortex. While differentiating cells leave the VZ to constitute the future neocortex, renewing radial glial progenitors stay in the VZ for subsequent divisions. The differential behaviour of progenitors and their differentiating progeny is essential for neocortical development; however, the mechanisms that ensure these beh...

  13. The interaction of glutathione S-transferase M1-null variants with tobacco smoke exposure and the development of childhood asthma

    DEFF Research Database (Denmark)

    Rogers, A J; Brasch-Andersen, C; Ionita-Laza, I;

    2009-01-01

    BACKGROUND: The glutathione S-transferase M1 (GSTM1)-null variant is a common copy number variant associated with adverse pulmonary outcomes, including asthma and airflow obstruction, with evidence of important gene-by-environment interactions with exposures to oxidative stress. OBJECTIVE......: To explore the joint interactive effects of GSTM1 copy number and tobacco smoke exposure on the development of asthma and asthma-related phenotypes in a family-based cohort of childhood asthmatics. METHODS: We performed quantitative PCR-based genotyping for GSTM1 copy number in children of self......-reported white ancestry with mild to moderate asthma in the Childhood Asthma Management Program. Questionnaire data regarding intrauterine (IUS) and post-natal, longitudinal smoke exposure were available. We performed both family-based and population-based tests of association for the interaction between GSTM1...

  14. Direct asymmetric aldol reaction using MBHA resin-supported peptide containing L-proline unit

    Institute of Scientific and Technical Information of China (English)

    Liang Zhang; Wen Bo Ding; Yong Ping Yu; Hong Bin Zou

    2009-01-01

    MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes,which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses.

  15. Asymmetric fuel share responses to relative price movements

    International Nuclear Information System (INIS)

    Following the fall in oil prices in 1986, and the lower-than-expected response of energy demand, recent work has focused upon the importance of asymmetric price elasticities of total energy demand. The irreversibility of new technology developed as a reaction to high price signals provides firm intuitive support for this idea. The unwillingness of consumers to believe that prices will remain low can also offer a basis for expecting asymmetry in lag structures: abstracting from technological development, the reactions to price movements may well be symmetrical, but will take longer to occur. Another general development, following the 1970s' price rises, has been the substantial fall in energy intensities in the OECD, leading to these economies becoming less exposed to external energy price 'shocks'. Therefore, some attention has also been focused upon asymmetric energy price impacts upon economic growth. (author)

  16. Asymmetric septal hypertrophy - a marker of hypertension in aortic stenosis (a SEAS substudy)

    DEFF Research Database (Denmark)

    Tuseth, Nora; Cramariuc, Dana; Rieck, Ashild E;

    2010-01-01

    Some patients with aortic stenosis develop asymmetric septal hypertrophy (ASH) that may influence the surgical approach and is associated with higher perioperative morbidity. The aim of this analysis was to characterize further this subtype of aortic stenosis patients.......Some patients with aortic stenosis develop asymmetric septal hypertrophy (ASH) that may influence the surgical approach and is associated with higher perioperative morbidity. The aim of this analysis was to characterize further this subtype of aortic stenosis patients....

  17. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-01

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe. PMID:22304253

  18. Asymmetric dark matter in braneworld cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)

    2014-06-01

    We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.

  19. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-01

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe.

  20. Asymmetric Dark Matter and Effective Operators

    CERN Document Server

    Buckley, Matthew R

    2011-01-01

    In order to annihilate in the early Universe to levels well below the measured dark matter density, asymmetric dark matter must possess large couplings to the Standard Model. In this paper, we consider effective operators which allow asymmetric dark matter to annihilate into quarks. In addition to a bound from requiring sufficient annihilation, the energy scale of such operators can be constrained by limits from direct detection and monojet searches at colliders. We show that the allowed parameter space for these operators is highly constrained, leading to non-trivial requirements that any model of asymmetric dark matter must satisfy.

  1. Preparation and Reactions of Amino Acid Ester Sulfones as New Remote Asymmetrical Induced Reagents

    Institute of Scientific and Technical Information of China (English)

    ZHOU,Cheng-He; BAI,Xue; LI,Tan-Qing; WU,Jun; Alfred Hassner

    2004-01-01

    @@ The development of chiral auxiliary-controlled asymmetric synthesis has been receiving increasing interest in recent yearsfi,2] Various chiral auxiliary reagents have been observed[3] and a lot of results showed that variation of the chiral auxiliary could influence asymmetric induction. Recently, it has been reported the reaction of the aminated sulfones as a remote chiral auxiliary with α,β-unsaturated carbonyl compounds.[4] Here we would like to report the preparation of amino acid ester sulfones as new remote asymmetrical induced reagents and their reactions with α,β-unsaturated esters.

  2. NONLINEAR EXTENSION OF ASYMMETRIC GARCH MODEL WITHIN NEURAL NETWORK FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Josip Arnerić

    2016-05-01

    Full Text Available The importance of volatility for all market participants has led to the development and application of various econometric models. The most popular models in modelling volatility are GARCH type models because they can account excess kurtosis and asymmetric effects of financial time series. Since standard GARCH(1,1 model usually indicate high persistence in the conditional variance, the empirical researches turned to GJR-GARCH model and reveal its superiority in fitting the asymmetric heteroscedasticity in the data. In order to capture both asymmetry and nonlinearity in data, the goal of this paper is to develop a parsimonious NN model as an extension to GJR-GARCH model and to determine if GJR-GARCH-NN outperforms the GJR-GARCH model.

  3. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  4. Why Do Nucleosomes Unwrap Asymmetrically?

    Science.gov (United States)

    de Bruin, Lennart; Tompitak, Marco; Eslami-Mossallam, Behrouz; Schiessel, Helmut

    2016-07-01

    Nucleosomes, DNA spools with a protein core, engage about three-quarters of eukaryotic DNA and play a critical role in chromosomal processes, ranging from gene regulation, recombination, and replication to chromosome condensation. For more than a decade, micromanipulation experiments where nucleosomes are put under tension, as well as the theoretical interpretations of these experiments, have deepened our understanding of the stability and dynamics of nucleosomes. Here we give a theoretical explanation for a surprising new experimental finding: nucleosomes wrapped onto the 601 positioning sequence (the sequence used in most laboratories) respond highly asymmetrically to external forces by always unwrapping from the same end. Using a computational nucleosome model, we show that this asymmetry can be explained by differences in the DNA mechanics of two very short stretches on the wrapped DNA portion. Our finding suggests that the physical properties of nucleosomes, here the response to forces, can be tuned locally by the choice of the underlying base-pair sequence. This leads to a new view of nucleosomes: a physically highly varied set of DNA-protein complexes whose properties can be tuned on evolutionary time scales to their specific function in the genomic context. PMID:26991771

  5. Twin Higgs Asymmetric Dark Matter

    CERN Document Server

    García, Isabel García; March-Russell, John

    2015-01-01

    We study Asymmetric Dark Matter (ADM) in the context of the minimal (Fraternal) Twin Higgs solution to the little hierarchy problem, with a twin sector with gauged $SU(3)' \\times SU(2)'$, a twin Higgs, and only third generation twin fermions. Naturalness requires the QCD$^\\prime$ scale $\\Lambda'_{\\rm QCD} \\simeq 0.5 - 20 \\ {\\rm GeV}$, and $t'$ to be heavy. We focus on the light $b'$ quark regime, $m_{b'} \\lesssim \\Lambda'_{\\rm QCD}$, where QCD$^\\prime$ is characterised by a single scale $\\Lambda'_{\\rm QCD}$ with no light pions. A twin baryon number asymmetry leads to a successful DM candidate: the spin-3/2 twin baryon, $\\Delta' \\sim b'b'b'$, with a dynamically determined mass ($\\sim 5 \\Lambda'_{\\rm QCD}$) in the preferred range for the DM-to-baryon ratio $\\Omega_{\\rm DM}/\\Omega_{\\rm baryon} \\simeq 5$. Gauging the $U(1)'$ group leads to twin atoms ($\\Delta'$ - $\\bar {\\tau'}$ bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo ...

  6. Chaos suppression through asymmetric coupling

    Science.gov (United States)

    Bragard, J.; Vidal, G.; Mancini, H.; Mendoza, C.; Boccaletti, S.

    2007-12-01

    We study pairs of identical coupled chaotic oscillators. In particular, we have used Roessler (in the funnel and no funnel regimes), Lorenz, and four-dimensional chaotic Lotka-Volterra models. In all four of these cases, a pair of identical oscillators is asymmetrically coupled. The main result of the numerical simulations is that in all cases, specific values of coupling strength and asymmetry exist that render the two oscillators periodic and synchronized. The values of the coupling strength for which this phenomenon occurs is well below the previously known value for complete synchronization. We have found that this behavior exists for all the chaotic oscillators that we have used in the analysis. We postulate that this behavior is presumably generic to all chaotic oscillators. In order to complete the study, we have tested the robustness of this phenomenon of chaos suppression versus the addition of some Gaussian noise. We found that chaos suppression is robust for the addition of finite noise level. Finally, we propose some extension to this research.

  7. Force on an Asymmetric Capacitor

    CERN Document Server

    Bahder, T B; Bahder, Thomas B.; Fazi, Chris

    2002-01-01

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of patents by Thomas Townsend Brown. At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes: ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least three orders of magnitude too small to explain the magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, however, it is difficult to see how ionic dr...

  8. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors. PMID:26430985

  9. Enhanced Second Harmonic Generation from Coupled Asymmetric Plasmonic Metal Nanostructures

    OpenAIRE

    Yildiz, Bilge Can; Tasgin, Mehmet Emre; Abak, Musa Kurtulus; Coskun, Sahin; Unalan, Husnu Emrah; Bek, Alpan

    2014-01-01

    We show that second harmonic generation can be enhanced by Fano resonant coupling of asymmetric plasmonic metal nanostructures. We develop a theoretical model examining the effects of electromagnetic interaction between two metal nanostructures on the second harmonic generation. We compare the second harmonic generation efficiency of a single plasmonic metal nanostructure with that of two coupled ones. We show that second harmonic generation from a single metal nanostructure can be enhanced a...

  10. Mechanistic Insights into Homogeneous and Heterogeneous Asymmetric Iron Catalysis

    Science.gov (United States)

    Sonnenberg, Jessica

    Our group has been focused on replacing toxic and expensive precious metal catalysts with iron for the synthesis of enantiopure compounds for industrial applications. During an investigation into the mechanism of asymmetric transfer hydrogenation with our first generation iron-(P-N-N-P) catalysts we found substantial evidence for zero-valent iron nanoparticles coated in chiral ligand acting as the active site. Extensive experimental and computational experiments were undertaken which included NMR, DFT, reaction profile analysis, substoichiometric poisoning, electron microscope imaging, XPS and multiphasic analysis, all of which supported the fact that NPs were the active species in catalysis. Reversibility of this asymmetric reaction on the nanoparticle surface was then probed using oxidative kinetic resolution of racemic alcohols, yielding modest enantiopurity and high turnover frequencies (TOF) for a range of aromatic alcohols. Efficient dehydrogenation of ammonia-borane for hydrogen evolution and the formation of B-N oligomers was also shown using the NP system, yielding highly active systems, with a maximum TOF of 3.66 H2/s-1 . We have also begun to focus on the development of iron catalysts for asymmetric direct hydrogenation of ketones using hydrogen gas. New chiral iron-(P-N-P) catalysts were developed and shown to be quite active and selective for a wide range of substrates. Mechanistic investigations primarily using NMR and DFT indicated that a highly active trans-dihydride species was being formed during catalyst activation. Lastly, a new library of chiral P-N-P and P-NH-P ligands were developed, as well as their corresponding iron complexes, some of which show promise for the development of future generations of active asymmetric direct hydrogenation catalysts.

  11. The Stability of Dynamic Contests with Asymmetric and Endogenous Prizes

    OpenAIRE

    Frederik Schmidt

    2008-01-01

    The paper develops a simple theoretical framework for analyzing repeated contests. At each stage of the infinitely repeated game, a Tullock contest is played by two players. We consider local stability of the Nash equilibrium with respect to adjustment speed and the level of the prize. The model is extended to an asymmetric valuation of the prize and to the case with an endogenous prize, where the level of the prize is influenced by the investments of the players.

  12. Reflection-asymmetric nuclear deformations within the Density Functional Theory

    CERN Document Server

    Olsen, E; Nazarewicz, W; Stoitsov, M; 10.1088/1742-6596/402/1/012034

    2013-01-01

    Within the nuclear density functional theory (DFT) we study the effect of reflection-asymmetric shapes on ground-state binding energies and binding energy differences. To this end, we developed the new DFT solver AxialHFB that uses an approximate second-order gradient to solve the Hartree-Fock-Bogoliubov equations of superconducting DFT with the quasi-local Skyrme energy density functionals. Illustrative calculations are carried out for even-even isotopes of radium and thorium.

  13. Kinematics and Dynamics of an Asymmetrical Parallel Robotic Wrist

    DEFF Research Database (Denmark)

    Wu, Guanglei

    2014-01-01

    This paper introduces an asymmetrical parallel robotic wrist, which can generate a decoupled unlimited-torsion motion and achieve high positioning accuracy. The kinematics, dexterity, and singularities of the manipulator are investigated to visualize the performance contours of the manipulator....... Using the method of Lagrange multipliers and considering all the mobile components, the equations of motion of the manipulator are derived to investigate the dynamic characteristics efficiently. The developed dynamic model is numerically illustrated and compared with its simplified formulation to show...

  14. Asymmetric dense matter in holographic QCD

    Directory of Open Access Journals (Sweden)

    Shin Ik Jae

    2012-02-01

    Full Text Available We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyperon matter with one light and one intermediate mass quarks. In addition to the vacuum properties of asymmetric matter, we calculate meson masses in asymmetric dense matter and discuss our results in the light of in-medium kaon masses.

  15. Massless sunset diagrams in finite asymmetric volumes

    CERN Document Server

    Niedermayer, Ferenc

    2016-01-01

    In this paper we present methods to compute massless sunset diagrams in finite asymmetric volumes in the framework of dimensional regularization and lattice regularization. We also consider 1-loop sums in both regularizations.

  16. Asymmetric cryptography based on wavefront sensing.

    Science.gov (United States)

    Peng, Xiang; Wei, Hengzheng; Zhang, Peng

    2006-12-15

    A system of asymmetric cryptography based on wavefront sensing (ACWS) is proposed for the first time to our knowledge. One of the most significant features of the asymmetric cryptography is that a trapdoor one-way function is required and constructed by analogy to wavefront sensing, in which the public key may be derived from optical parameters, such as the wavelength or the focal length, while the private key may be obtained from a kind of regular point array. The ciphertext is generated by the encoded wavefront and represented with an irregular array. In such an ACWS system, the encryption key is not identical to the decryption key, which is another important feature of an asymmetric cryptographic system. The processes of asymmetric encryption and decryption are formulized mathematically and demonstrated with a set of numerical experiments.

  17. ASYMMETRICAL GONADAL DYSGENESIS IN A MALE PATIENT : A RARE CASE REPORT

    Directory of Open Access Journals (Sweden)

    Anilkumar

    2015-03-01

    Full Text Available BACKGROUND: Asymmetric Gonadal dysgenesis ( AGD very rare intersex disorder seen in less than 5% of all intersex disorders. Asymmetric gonadal dysgenesis refers to individuals who have abnormal and symmetrical gonadal development , usually a differentiated gonad on one side and a steak gonad or steak testis on other side. The importance of identifying these lesions are important because risk of development of malignancy as high as 30% , which always influenced by y - chromosome. CASE REPORT : A 21 year old male patient presented with left s ided obstructed inguinal hernia with cryptorchidism. On exploratory laparotomy , uterus with bilateral adnexa and testis are seen. Microscopy revealed features of asymmetric gonadal dysgenesis. True hermaph - roditism was the closest differential diagnosis an d was excluded by the strict histological criteria necessary for diagnosis. CONCLUSION: Asymmetric gonadal dysgenesis is a rare disorder. The rare nature of this entity and its clinical implications merits its reporting.

  18. Worst Asymmetrical Short-Circuit Current

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holmstrøm, O; Grastrup, L;

    2010-01-01

    In a typical power plant, the production scenario and the short-circuit time were found for the worst asymmetrical short-circuit current. Then, a sensitivity analysis on the missing generator values was realized in order to minimize the uncertainty of the results. Afterward the worst asymmetrical...... short-circuit current was analyzed in order to compare the results with the allowable DC current component based in the IEC. Finally the normal operating condition for the power plant was modeled....

  19. An asymmetric pericyclic cascade approach to oxindoles

    OpenAIRE

    Richmond, Edward

    2014-01-01

    The research in this thesis describes an asymmetric pericyclic cascade approach to the synthesis of a range of enantioenriched oxindoles using enantiopure oxazolidine derived nitrones and disubstituted ketenes. Chapter 1 aims to place this work in the context of the literature, describing other commonly employed or state-of-the-art asymmetric approaches to oxindoles and related compounds. Examples of where these approaches have been used successfully in the total synthesis of related indol...

  20. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    OpenAIRE

    Gobade, N. G.; Marina Koland; K H Harish

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist...

  1. Novel strategies for asymmetric hydrogenation reactions

    OpenAIRE

    Chen, Dianjun

    2011-01-01

    This thesis describes two novel possibilities for asymmetric hydrogenation: enantioselective hydrogenation using chiral ionic liquid systems and metal-free hydrogenation with boranes. In the first part, asymmetric hydrogenation systems using chiral ionic liquids in combination with racemic rhodium catalyst are presented. Enantioselectivities up to 69% ee were achieved in homogeneous Rh-catalyzed hydrogenation with tropos ligand (BIPHEP, sulfonated BIPHEP) in a proline derived cation chiral io...

  2. Asymmetric septal hypertrophy and hypothyroidism in children.

    OpenAIRE

    Altman, D I; Murray, J.; Milner, S.; Dansky, R; Levin, S. E.

    1985-01-01

    Any echocardiographic study of two children with hypothyroidism demonstrated the presence of asymmetric septal hypertrophy. One child died aged 11 months, and pronounced thickening of the interventricular septum was confirmed at necropsy. There was also hypertrophy of the left ventricular free wall. Histological examination showed only slight muscle fibre disarray, but there was striking vacuolation and hypertrophy of muscle fibres. In the second case, a child aged five years, the asymmetric ...

  3. Recrystallization Texture Development in Asymmetrically Rolled Non-oriented Silicon Steel%异步轧制无取向硅钢的再结晶织构演变

    Institute of Scientific and Technical Information of China (English)

    裴伟; 沙玉辉; 赵瑞清; 左良

    2012-01-01

    在无取向硅钢冷轧过程中采用同步轧制和速比为1.06,1.125,1.19的异步轧制,以考察异步轧制对冷轧和再结晶织构的影响.研究发现,异步轧制减弱冷轧织构中{001}~{112}〈110〉组分,增强{111}〈112〉并减弱{111}〈110〉组分.{111}〈112〉和{111}~{225}〈110〉形变晶粒内剪切带处分别形成η(〈001〉∥RD)及偏离其15°的η′(Ψ=75°,θ=0~45°,φ=0°)再结晶晶粒,η′因晶核尺寸优势发展成为主要织构组分.异步轧制下形变织构的变化有利于改善再结晶织构特征及性能,其影响随速比增大而增强.%The non-oriented silicon steel sheets were produced by asymmetric cold rolling with three speed ratios of 1.06, 1. 125 and 1.19, respectively, and produced also by conventional symmetric cold rolling for comparison. It was found that the asymmetric rolling weakens {001} - {112} 〈110〉components in a fiber (〈110〉//RD), while strengthens {111} 〈112〉 and weakens {111}〈110〉 in γ fiber (〈111〉//ND). EBSD results showed that η(〈001〉//RD) and η′(Ψ=75°,θ=0~45°,φ=0°) grains nucleate within shear bands in t lllt (112) and {111}- {225} 〈110〉 deformed grains, respectively,η′becomes the main recrystallization component because of nuclei size advantage. Reerystallization texture and magnetic properties can be improved by the change of cold rolling texture induced by asymmetric rolling, and the effect of asymmetric rolling is more obvious with the increasing of speed ratio.

  4. Metal-catalyzed Asymmetric Hetero-Diels-Alder Reactions of Unactivated Dienes with Glyoxylates

    DEFF Research Database (Denmark)

    Johannsen, Mogens; Yao, Sulan; Graven, Anette

    1998-01-01

    The development of a catalytic asymmetric hetero-Diels-Alder methodology for the reaction of unactivated dienes with glyoxylates is presented. Several different asymmetric catalysts can be used, but copper-bisoxazolines and aluminium-BINOL give the highest yield, and the best chemo- and...... enantioselectivities. The reaction course is dependent on several factors such as the solvent and the anions coordinated to the catalyst. The scope of the reaction is outlined by the total synthesis of a natural occurring actinidiolide....

  5. Asymmetric severity of diabetic retinopathy in Waardenburg syndrome: response to authors

    OpenAIRE

    Gupta A; Raman R; Sharma T

    2012-01-01

    Aditi Gupta, Rajiv Raman, Tarun SharmaShri Bhagwan Mahavir Department of Vitreoretinal Services, Sankara Nethralaya, Chennai, Tamil Nadu, IndiaWe read with great interest the recent article by Kashima et al,1 in which the authors report a case of asymmetric severity of diabetic retinopathy in Waardenburg syndrome. We want to highlight some concerns regarding this report. Previous reports have described many systemic and local factors associated with the development of asymmetric diabetic reti...

  6. Enantioconvergent synthesis by sequential asymmetric Horner-Wadsworth-Emmons and palladium-catalyzed allylic substitution reactions

    DEFF Research Database (Denmark)

    Pedersen, Torben Møller; Hansen, E. Louise; Kane, John;

    2001-01-01

    A new method for enantioconvergent synthesis has been developed. The strategy relies on the combination of an asymmetric Horner-Wadsworth-Emmons (HWE) reaction and a palladium-catalyzed allylic substitution. Different $alpha@-oxygen-substituted, racemic aldehydes were initially transformed by...... asymmetric HWE reactions into mixtures of two major $alpha@,$beta@-unsaturated esters, possessing opposite configurations at their allylic stereocenters as well as opposite alkene geometry. Subsequently, these isomeric mixtures of alkenes could be subjected to palladium-catalyzed allylic substitution...

  7. The design of an asymmetric bionic branching channel for electronic chips cooling

    Science.gov (United States)

    Xu, Shanglong; Qin, Jie; Guo, Wei; Fang, Kuang

    2013-06-01

    Inspired by the wing vein of Lepidoptera, a designment of asymmetric bionic branching channel for electronic chips cooling is developed. Lepidoptera vein D was chosen to measure the angle of first and second branch level. Based on these regular patterns, an asymmetric bionic branching channel is designed in a 35 mm × 35 mm chip. Comparing with fractal-like branching channel, it provides a stronger heat transfer capability, lower pressure drop and lower flow resistance in the experiment.

  8. Something gone awry: unsolved mysteries in the evolution of asymmetric animal genitalia

    OpenAIRE

    Schilthuizen, M

    2013-01-01

    The great diversity in genital shape and function across and within the animal phyla hamper the identification of specific evolutionary trends that stretch beyond the limits of the group under study. Asymmetry might be a trait in genital morphology that could play a unifying role in the evolutionary biology of genitalia. Here, I review the current knowledge on the taxonomic distribution, phylogenetic patterns, genetics, development, and ecology of asymmetric (chiral) genitalia. Asymmetric gen...

  9. Asymmetric Random Matrices: What do We Need them For?

    International Nuclear Information System (INIS)

    Complex systems are typically represented by large ensembles of observations. Correlation matrices provide an efficient formal framework to extract information from such multivariate ensembles and identify in a quantifiable way patterns of activity that are reproducible with statistically significant frequency compared to a reference chance probability, usually provided by random matrices as fundamental reference. The character of the problem and especially the symmetries involved must guide the choice of random matrices to be used for the definition of a baseline reference. For standard correlation matrices this is the Wishart ensemble of symmetric random matrices. The real world complexity however often shows asymmetric information flows and therefore more general correlation matrices are required to adequately capture the asymmetry. Here we first summarize the relevant theoretical concepts. We then present some examples of human brain activity where asymmetric time-lagged correlations are evident and hence highlight the need for further theoretical developments. (author)

  10. Asymmetric excitation of surface plasmons by dark mode coupling

    KAUST Repository

    Zhang, X.

    2016-02-19

    Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.

  11. Asymmetric trienamine catalysis: new opportunities in amine catalysis.

    Science.gov (United States)

    Kumar, Indresh; Ramaraju, Panduga; Mir, Nisar A

    2013-02-01

    Amine catalysis, through HOMO-activating enamine and LUMO-activating iminium-ion formation, is receiving increasing attention among other organocatalytic strategies, for the activation of unmodified carbonyl compounds. Particularly, the HOMO-raising activation concept has been applied to the greatest number of asymmetric transformations through enamine, dienamine, and SOMO-activation strategies. Recently, trienamine catalysis, an extension of amine catalysis, has emerged as a powerful tool for synthetic chemists with a novel activation strategy for polyenals/polyenones. In this review article, we discuss the initial developments of trienamine catalysis for highly asymmetric Diels-Alder reactions with different dienophiles and emerging opportunities for other types of cycloadditions and cascade reactions.

  12. Asymmetric excitation of surface plasmons by dark mode coupling.

    Science.gov (United States)

    Zhang, Xueqian; Xu, Quan; Li, Quan; Xu, Yuehong; Gu, Jianqiang; Tian, Zhen; Ouyang, Chunmei; Liu, Yongmin; Zhang, Shuang; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2016-02-01

    Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities. PMID:26989777

  13. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules.

    Science.gov (United States)

    Smyth, Jeremy T; Schoborg, Todd A; Bergman, Zane J; Riggs, Blake; Rusan, Nasser M

    2015-08-01

    Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species. PMID:26289801

  14. High-Voltage, Asymmetric-Waveform Generator

    Science.gov (United States)

    Beegle, Luther W.; Duong, Tuan A.; Duong, Vu A.; Kanik, Isik

    2008-01-01

    The shapes of waveforms generated by commercially available analytical separation devices, such as some types of mass spectrometers and differential mobility spectrometers are, in general, inadequate and result in resolution degradation in output spectra. A waveform generator was designed that would be able to circumvent these shortcomings. It is capable of generating an asymmetric waveform, having a peak amplitude as large as 2 kV and frequency of several megahertz, which can be applied to a capacitive load. In the original intended application, the capacitive load would consist of the drift plates in a differential-mobility spectrometer. The main advantage to be gained by developing the proposed generator is that the shape of the waveform is made nearly optimum for various analytical devices requiring asymmetric-waveform such as differential-mobility spectrometers. In addition, this waveform generator could easily be adjusted to modify the waveform in accordance with changed operational requirements for differential-mobility spectrometers. The capacitive nature of the load is an important consideration in the design of the proposed waveform generator. For example, the design provision for shaping the output waveform is based partly on the principle that (1) the potential (V) on a capacitor is given by V=q/C, where C is the capacitance and q is the charge stored in the capacitor; and, hence (2) the rate of increase or decrease of the potential is similarly proportional to the charging or discharging current. The proposed waveform generator would comprise four functional blocks: a sine-wave generator, a buffer, a voltage shifter, and a high-voltage switch (see Figure 1). The sine-wave generator would include a pair of operational amplifiers in a feedback configuration, the parameters of which would be chosen to obtain a sinusoidal timing signal of the desired frequency. The buffer would introduce a slight delay (approximately equal to 20 ns) but would otherwise

  15. Distinct characteristics of asymmetric magnetic reconnections: Observational results from the exhaust region at the dayside magnetopause

    Science.gov (United States)

    Zhang, Y. C.

    2016-06-01

    Magnetic reconnection plays a key role in the conversion of magnetic energy into the thermal and kinetic energy of plasma. On either side of the diffusion region in space plasma, the conditions for the occurrence of reconnections are usually not symmetric. Previous theoretical studies have predicted that reconnections under asymmetric conditions will bear different features compared with those of symmetric reconnections, and numerical simulations have verified these distinct features. However, to date, the features of asymmetric reconnections have not been thoroughly investigated using in situ observations; thus, some results from theoretical studies and simulations have not been tested with observations sufficiently well. Here, spacecraft observations are used in a statistical investigation of asymmetric magnetic reconnection exhaust at the dayside magnetopause. The resulting observational features are consistent with the theoretical predictions. The results presented here advance our understanding of the development of reconnections under asymmetric conditions.

  16. Renewable resource management under asymmetric information

    DEFF Research Database (Denmark)

    Jensen, Frank; Andersen, Peder; Nielsen, Max

    2013-01-01

    Asymmetric information between fishermen and the regulator is important within fisheries. The regulator may have less information about stock sizes, prices, costs, effort, productivity and catches than fishermen. With asymmetric information, a strong analytical tool is principal-agent analysis....... In this paper, we study asymmetric information about productivity within a principal-agent framework and a tax on fishing effort is considered. It is shown that a second best optimum can be achieved if the effort tax is designed such that low-productivity agents rent is exhausted, while high-productivity agents...... receive an information rent. The information rent is equivalent to the total incentive cost. The incentive costs arise as we want to reveal the agent's type....

  17. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  18. GENERATION OF ASYMMETRIC F-v CHARACTERISTICS FOR SYMMETRIC MR DAMPERS

    Institute of Scientific and Technical Information of China (English)

    WANG Enrong; YE Biaoming; MA Xiaoqing; SU Chunyi; RAKHEJA Subhash

    2006-01-01

    An asymmetric damping force generation algorithm is originally proposed to yield the asymmetric force-velocity characteristics for the symmetric magneto-rheological (MR) dampers. The command current is formulated in an asymmetric manner to excite the symmetric MR dampers by employing the "on-off" control law in response to the direction of velocity, and a smooth modulation function is developed without phase shift to suppress strong transients in the damping forces caused by the current-switching discontinuity. The effectiveness of the proposed algorithm is evaluated by analyzing the dynamic responses of a quarter-vehicle suspension system with a symmetric MR-damper by modulating the command current into the asymmetric manner. The simulation results show that the proposed algorithm could achieve a better compromise between the conflicting requirements of the asymmetric damping force ratio and the force-velocity curve smoothness, and the asymmetric damping MR-suspension design can ideally improve the road holding and ride performances of vehicle motion. The proposed algorithm can be generally incorporated with a controller synthesis to realize an intelligent vehicle suspension design with the symmetric MR dampers.

  19. Asymmetric counter propagation of domain walls

    Science.gov (United States)

    Andrade-Silva, I.; Clerc, M. G.; Odent, V.

    2016-07-01

    Far from equilibrium systems show different states and domain walls between them. These walls, depending on the type of connected equilibria, exhibit a rich spatiotemporal dynamics. Here, we investigate the asymmetrical counter propagation of domain walls in an in-plane-switching cell filled with a nematic liquid crystal. Experimentally, we characterize the shape and speed of the domain walls. Based on the molecular orientation, we infer that the counter propagative walls have different elastic deformations. These deformations are responsible of the asymmetric counter propagating fronts. Theoretically, based on symmetry arguments, we propose a simple bistable model under the influence of a nonlinear gradient, which qualitatively describes the observed dynamics.

  20. Asymmetric acoustic transmission in multiple frequency bands

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hong-xiang, E-mail: jsdxshx@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China); Yuan, Shou-qi, E-mail: Shouqiy@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Shu-yi [Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-11-23

    We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

  1. Cell-sized asymmetric lipid vesicles facilitate the investigation of asymmetric membranes

    Science.gov (United States)

    Kamiya, Koki; Kawano, Ryuji; Osaki, Toshihisa; Akiyoshi, Kazunari; Takeuchi, Shoji

    2016-09-01

    Asymmetric lipid giant vesicles have been used to model the biochemical reactions in cell membranes. However, methods for producing asymmetric giant vesicles lead to the inclusion of an organic solvent layer that affects the mechanical and physical characteristics of the membrane. Here we describe the formation of asymmetric giant vesicles that include little organic solvent, and use them to investigate the dynamic responses of lipid molecules in the vesicle membrane. We formed the giant vesicles via the inhomogeneous break-up of a lipid microtube generated by applying a jet flow to an asymmetric planar lipid bilayer. The asymmetric giant vesicles showed a lipid flip-flop behaviour in the membrane, superficially similar to the lipid flip-flop activity observed in apoptotic cells. In vitro synthesis of membrane proteins into the asymmetric giant vesicles revealed that the lipid asymmetry in bilayer membranes improves the reconstitution ratio of membrane proteins. Our asymmetric giant vesicles will be useful in elucidating lipid–lipid and lipid–membrane protein interactions involved in the regulation of cellular functions.

  2. Chilly dark sectors and asymmetric reheating

    Science.gov (United States)

    Adshead, Peter; Cui, Yanou; Shelton, Jessie

    2016-06-01

    In a broad class of theories, the relic abundance of dark matter is determined by interactions internal to a thermalized dark sector, with no direct involvement of the Standard Model (SM). We point out that these theories raise an immediate cosmological question: how was the dark sector initially populated in the early universe? Motivated in part by the difficulty of accommodating large amounts of entropy carried in dark radiation with cosmic microwave background measurements of the effective number of relativistic species at recombination, N eff , we aim to establish which admissible cosmological histories can populate a thermal dark sector that never reaches thermal equilibrium with the SM. The minimal cosmological origin for such a dark sector is asymmetric reheating, when the same mechanism that populates the SM in the early universe also populates the dark sector at a lower temperature. Here we demonstrate that the resulting inevitable inflaton-mediated scattering between the dark sector and the SM can wash out a would-be temperature asymmetry, and establish the regions of parameter space where temperature asymmetries can be generated in minimal reheating scenarios. Thus obtaining a temperature asymmetry of a given size either restricts possible inflaton masses and couplings or necessitates a non-minimal cosmology for one or both sectors. As a side benefit, we develop techniques for evaluating collision terms in the relativistic Boltzmann equation when the full dependence on Bose-Einstein or Fermi-Dirac phase space distributions must be retained, and present several new results on relativistic thermal averages in an appendix.

  3. Asymmetric conditional volatility in international stock markets

    Science.gov (United States)

    Ferreira, Nuno B.; Menezes, Rui; Mendes, Diana A.

    2007-08-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.

  4. Weak chaos in the asymmetric heavy top

    CERN Document Server

    Barrientos, M; Ranada, A F

    1995-01-01

    We consider the dynamics of the slightly asymmetric heavy top, a non-integrable system obtained from the Lagrange top by breaking the symmetry of its inertia tensor. It shows signs of weak chaos, which we study numerically. We argue that it is a good example for introducing students to non-integrability and chaos. (author)

  5. Asymmetric cell division: a persistent issue?

    OpenAIRE

    Aakre, Christopher D.; Laub, Michael T.

    2012-01-01

    Heterogeneity within a clonal population of cells can increase survival in the face of environmental stress. In a recent issue of Science, Aldridge et al. (2012) demonstrate that cell division in mycobacteria is asymmetric, producing daughter cells that differ in size, growth rate, and susceptibility to antibiotics.

  6. Asymmetric Total Synthesis of (-)-Cladospolide B

    Institute of Scientific and Technical Information of China (English)

    WANG,Wen-Kuan; ZHANG,Ji-Yong; HE,Jin-Mei; TANG,Shi-Bing; WANG,Xiao-Lei; SHE,Xue-Gong; PAN,Xin-Fu

    2008-01-01

    An enantioselective total synthesis of (-)-cladospolide B was described.The key steps in this synthesis include (a) a Sharpless asymmetric dihydroxylation to elaborate syn diol at C-4 and C-5 positions;(b) a Mitsunobu esterification to reverse the configuration at C-11 from (S) to (R);and (c) a ring-closing metathesis to access the 12-membered macrocyclic ring.

  7. Evidence of asymmetric top in 130Ba

    International Nuclear Information System (INIS)

    Introduced is a new relation connecting moment of inertia, Lipas parameter and asymmetric rotor model energies and put forward much closer trend in odd even staggering of quasi γ-band. A different view point regarding generation of quasi γ-band in 130Ba have been presented

  8. The Asymmetric Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    2016-01-01

    are asymmetric: During peak-to-trough periods of investor sentiment (sentiment contractions), high sentiment predicts low future returns for the cross section of speculative stocks and for the market overall, whereas the relationship between sentiment and future returns is positive but relatively weak during...... trough-to-peak episodes (sentiment expansions). Overall, these results match theories and anecdotal accounts of investor sentiment....

  9. Detection loophole in asymmetric Bell experiments

    OpenAIRE

    Brunner, Nicolas; Gisin, Nicolas; Scarani, Valerio; Simon, Christoph

    2007-01-01

    The problem of closing the detection loophole with asymmetric systems, such as entangled atom-photon pairs, is addressed. We show that, for the Bell inequality I_3322, a minimal detection efficiency of 43% can be tolerated for one of the particles, if the other one is always detected. We also study the influence of noise and discuss the prospects of experimental implementation.

  10. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  11. Attentional Control and Asymmetric Associative Priming

    Science.gov (United States)

    Hutchison, Keith A.; Heap, Shelly J.; Neely, James H.; Thomas, Matthew A.

    2014-01-01

    Participants completed a battery of 3 attentional control (AC) tasks (OSPAN, antisaccade, and Stroop, as in Hutchison, 2007) and performed a lexical decision task with symmetrically associated (e.g., "sister-brother") and asymmetrically related primes and targets presented in both the forward (e.g., "atom-bomb") and backward…

  12. Catalytic asymmetric synthesis of mycocerosic acid

    NARCIS (Netherlands)

    ter Horst, B.; Feringa, B.L.; J. Minnaard, A.

    2007-01-01

    The first catalytic asymmetric total synthesis of mycocerosic acid was achieved via the application of iterative enantioselective 1,4-addition reactions and allows for the efficient construction of 1,3-polymethyl arrays with full stereocontrol; further exemplified by the synthesis of tetramethyl-dec

  13. Asymmetric relationships between proteins shape genome evolution.

    NARCIS (Netherlands)

    Notebaart, R.A.; Kensche, P.R.; Huynen, M.A.; Dutilh, B.E.

    2009-01-01

    BACKGROUND: The relationships between proteins are often asymmetric: one protein (A) depends for its function on another protein (B), but the second protein does not depend on the first. In metabolic networks there are multiple pathways that converge into one central pathway. The enzymes in the conv

  14. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical dierentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  15. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    2012-01-01

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical differentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  16. Asymmetric Bulkheads for Cylindrical Pressure Vessels

    Science.gov (United States)

    Ford, Donald B.

    2007-01-01

    Asymmetric bulkheads are proposed for the ends of vertically oriented cylindrical pressure vessels. These bulkheads, which would feature both convex and concave contours, would offer advantages over purely convex, purely concave, and flat bulkheads (see figure). Intended originally to be applied to large tanks that hold propellant liquids for launching spacecraft, the asymmetric-bulkhead concept may also be attractive for terrestrial pressure vessels for which there are requirements to maximize volumetric and mass efficiencies. A description of the relative advantages and disadvantages of prior symmetric bulkhead configurations is prerequisite to understanding the advantages of the proposed asymmetric configuration: In order to obtain adequate strength, flat bulkheads must be made thicker, relative to concave and convex bulkheads; the difference in thickness is such that, other things being equal, pressure vessels with flat bulkheads must be made heavier than ones with concave or convex bulkheads. Convex bulkhead designs increase overall tank lengths, thereby necessitating additional supporting structure for keeping tanks vertical. Concave bulkhead configurations increase tank lengths and detract from volumetric efficiency, even though they do not necessitate additional supporting structure. The shape of a bulkhead affects the proportion of residual fluid in a tank that is, the portion of fluid that unavoidably remains in the tank during outflow and hence cannot be used. In this regard, a flat bulkhead is disadvantageous in two respects: (1) It lacks a single low point for optimum placement of an outlet and (2) a vortex that forms at the outlet during outflow prevents a relatively large amount of fluid from leaving the tank. A concave bulkhead also lacks a single low point for optimum placement of an outlet. Like purely concave and purely convex bulkhead configurations, the proposed asymmetric bulkhead configurations would be more mass-efficient than is the flat

  17. The role of ghrelin, leptin and insulin in foetal development

    Directory of Open Access Journals (Sweden)

    Magdalena Warchoł

    2014-06-01

    Full Text Available introduction and objective. The growing epidemic of childhood obesity has forced scientists to search for methods to prevent feeding disorders. Increasing interest in appetite regulating hormones has revealed their influence on energy homeostasis after birth or even in[i] utero[/i]. state of knowledge. The presence of ghrelin in the stomach of human foetuses and the distinctive production in the pancreas of neonates suggests the role of ghrelin in pre- and post-natal development. The neonatal period appears to be a critical time for the formation of adipose tissue-hypothalamus circuits, thus the amount of adipocytes in foetal life may be a major regulator of food intake. Insulin’s orexigenic effect in the arcuate nucleus of the hypothalamus can be a major modulator of foetal development. objective. This review, based on available literature, aims to analyses the role of appetite regulating hormones in foetal development. summary. Different concentrations of hormones, such as ghrelin, leptin and insulin during foetal life raises the question whether or not they can be modulated, thereby avoiding obesity before birth. Children with pancreas agenesis showed smaller body size at birth, which emphasises the probable role of insulin in foetal growth. Study of sheep foetuses with IUGR confirmed these finding. Appetite-regulating hormones show different roles in foetal development and seem to be essential in the perinatal period.

  18. Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter

    DEFF Research Database (Denmark)

    Masina, Isabella; Sannino, Francesco

    2011-01-01

    The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown...... component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton...... flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric....

  19. Par1b induces asymmetric inheritance of plasma membrane domains via LGN-dependent mitotic spindle orientation in proliferating hepatocytes

    NARCIS (Netherlands)

    Slim, Christiaan L; Lázaro-Diéguez, Francisco; Bijlard, Marjolein; Toussaint, Mathilda J M; de Bruin, Alain; Du, Quansheng; Müsch, Anne; van Ijzendoorn, Sven C D

    2013-01-01

    The development and maintenance of polarized epithelial tissue requires a tightly controlled orientation of mitotic cell division relative to the apical polarity axis. Hepatocytes display a unique polarized architecture. We demonstrate that mitotic hepatocytes asymmetrically segregate their apical p

  20. Omics and modeling approaches approaches for understanding regulation of asymmetric cell divisions in Arabidopsis and other angiosperm plants.

    NARCIS (Netherlands)

    Kajala, K.; Ramakrishna, A.; Fisher, A.; Bergmann, D.C.; Smet, De I.; Sozzani, R.; Weijers, D.; Brady, S.M.

    2014-01-01

    Background Asymmetric cell divisions are formative divisions that generate daughter cells of distinct identity. These divisions are coordinated by either extrinsic (‘niche-controlled’) or intrinsic regulatory mechanisms and are fundamentally important in plant development. Scope This review describe

  1. Kinematics and Dynamics of an Asymmetrical Parallel Robotic Wrist

    Directory of Open Access Journals (Sweden)

    Guanglei Wu

    2014-01-01

    Full Text Available This paper introduces an asymmetrical parallel robotic wrist, which can generate a decoupled unlimited-torsion motion and achieve high positioning accuracy. The kinematics, dexterity, and singularities of the manipulator are investigated to visualize the performance contours of the manipulator. Using the method of Lagrange multipliers and considering all the mobile components, the equations of motion of the manipulator are derived to investigate the dynamic characteristics efficiently. The developed dynamic model is numerically illustrated and compared with its simplified formulation to show its computation accuracy.

  2. Adaptive synchronization in an array of asymmetric coupled neural networks

    Institute of Scientific and Technical Information of China (English)

    Gao Ming; Cui Bao-Tong

    2009-01-01

    This paper investigates the global synchronization in an array of linearly coupled neural networks with constant and delayed coupling. By a simple combination of adaptive control and linear feedback with the updated laws, some sufficient conditions are derived for global synchronization of the coupled neural networks. The coupling configuration matrix is assumed to be asymmetric, which is more coincident with the realistic network. It is shown that the approaches developed here extend and improve the earlier works. Finally, numerical simulations are presented to demonstrate the effectiveness of the theoretical results.

  3. Crystallization of asymmetric patchy models for globular proteins in solution

    Science.gov (United States)

    Fusco, Diana; Charbonneau, Patrick

    2013-07-01

    Asymmetric patchy particle models have recently been shown to describe the crystallization of small globular proteins with near-quantitative accuracy. Here, we investigate how asymmetry in patch geometry and bond energy generally impacts the phase diagram and nucleation dynamics of this family of soft matter models. We find the role of the geometry asymmetry to be weak, but the energy asymmetry to markedly interfere with the crystallization thermodynamics and kinetics. These results provide a rationale for the success and occasional failure of the proposal of George and Wilson for protein crystallization conditions as well as physical guidance for developing more effective protein crystallization strategies.

  4. Asymmetric de Finetti Theorem for Infinite-dimensional Quantum Systems

    CERN Document Server

    Niu, Murphy Yuezhen

    2016-01-01

    The de Finetti representation theorem for continuous variable quantum system is first developed to approximate an N-partite continuous variable quantum state with a convex combination of independent and identical subsystems, which requires the original state to obey permutation symmetry conditioned on successful experimental verification on k of N subsystems. We generalize the de Finetti theorem to include asymmetric bounds on the variance of canonical observables and biased basis selection during the verification step. Our result thereby enables application of infinite-dimensional de Finetti theorem to situations where two conjugate measurements obey different statistics, such as the security analysis of quantum key distribution protocols based on squeezed state against coherent attack.

  5. Electromagnetically induced grating in asymmetric quantum wells via Fano interference.

    Science.gov (United States)

    Zhou, Fengxue; Qi, Yihong; Sun, Hui; Chen, Dijun; Yang, Jie; Niu, Yueping; Gong, Shangqing

    2013-05-20

    We propose a scheme for obtaining an electromagnetically induced grating in an asymmetric semiconductor quantum well (QW) structure via Fano interference. In our structure, owing to Fano interference, the diffraction intensity of the grating, especially the first-order diffraction, can be significantly enhanced. The diffraction efficiency of the grating can be controlled efficiently by tuning the control field intensity, the interaction length, the coupling strength of tunneling, etc. This investigation may be used to develop novel photonic devices in semiconductor QW systems. PMID:23736445

  6. Assessment of telomere length during post-natal period in offspring produced by a bull and its fibroblast derived clone

    Directory of Open Access Journals (Sweden)

    Roberto Puglisi

    2014-03-01

    Conclusions: The results have revealed a moderate shortening of telomeres in the offspring of the clone with respect to control. However, this study did not evidence differences in the two progenies that suggest welfare problems during the first year of life.

  7. The role of routine post-natal abdominal ultrasound for newborns in a resource-poor setting: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Omokhodion Samuel I

    2011-07-01

    Full Text Available Abstract Background- Neonatal abdominal ultrasound is usually performed in Nigeria to investigate neonatal symptoms rather than as a follow up to evaluate fetal abnormalities which were detected on prenatal ultrasound. The role of routine obstetric ultrasonography in the monitoring of pregnancy and identification of fetal malformations has partly contributed to lowering of fetal mortality rates. In Nigeria which has a high maternal and fetal mortality rate, many pregnant women do not have ante-natal care and not infrequently, women also deliver their babies at home and only bring the newborns to the clinics for immunization. Even when performed, most routine obstetric scans are not targeted towards the detection of fetal abnormalities. The aim of the present study is to evaluate the benefit of routinely performing abdominal scans on newborns with a view to detecting possible abnormalities which may have been missed ante-natally. Methods- This was a longitudinal study of 202 consecutive, apparently normal newborns. Routine clinical examination and abdominal ultrasound scans were performed on the babies by their mother's bedside, before discharge. Neonates with abnormal initial scans had follow-up scans. Results- There were 108 males and 94 females. There were 12 (5.9% abnormal scans seen in five male and seven female neonates. Eleven of the twelve abnormalities were in the kidneys, six on the left and five on the right. Three of the four major renal anomalies- absent kidney, ectopic/pelvic kidney and two cases of severe hydronephrosis were however on the left side. There was one suprarenal abnormality on the right suspected to be a possible infected adrenal haemorrage. Nine of the abnormal cases reported for follow- up and of these, two cases had persistent severe abnormalities. Conclusions- This study demonstrated a 5.9% incidence of genito urinary anomalies on routine neonatal abdominal ultrasound in this small population. Routine obstetric USS is very useful but inadequate availability of skilled personnel and cost implications create great challenges in poor resource settings like Nigeria. However, awareness should be created so that parents who can afford such investigations can make informed decisions.

  8. Assessment of telomere length during post-natal period in offspring produced by a bull and its fibroblast derived clone

    Institute of Scientific and Technical Information of China (English)

    RobertoPuglisi; AndreaGalli; AnnaPozzi; RobertaVanni; DonatellaBalduzzi; Irina Lagutina; Silvia Colleoni; GiovannaLazzari; CesareGalli; GraziellaBongioni

    2014-01-01

    Objective:To investigate the telomere length in bovine offspring produced by a cloned and control bull, and the telomerase activity in embryos produced with the same technology. Methods:Five daughters of a control and five daughters of a bull cloned using a fibroblast of the control were produced byIVF using sperm of the two bulls.Blood samples of the offspring were collected at2,6, and12 months of age andthe relative telomere length(RTL) was assessed by flow cytometry.At same time the body growth, hematological profile, and clinical biochemistry of the same progeny was extensively surveyed, and results have been reported in a previous work.Thereafter, the telomerase activity was assessed using a real timePCR quantitative assay in groups of embryos produced with the same technology.Results:The offspring of the clone exhibited a modest, but significant(P<0.05), shortening of the telomeres(21.36%,20.56% and 20.56%) compared to that of the control(23.78%,23.53% and22.43%) as mean values determined at2,6 and12 months, respectively.Shortening of telomeres in respect to the age was not significant. No statistical difference was reported between telomerase activity assessed in144 cloned (3.4-03±2.4-03 amoles/μL) and80 control(2.1-03±1.8-03 amoles/μL) embryos.Conclusions:The results have revealed a moderate shortening of telomeres in the offspring of the clone with respect to control.However, this study did not evidence differences in the two progenies that suggest welfare problems during the first year of life.

  9. 孕前、孕期和产后保健%Preconception, prenatal and post-natal cares

    Institute of Scientific and Technical Information of China (English)

    郁君; 周健

    2013-01-01

    ABSTRACT World Health Organization puts forward the tertiary prevention strategies of birth defects in order to reduce its occurrence. Among them, primary prevention refers to comprehensive intervention to prevent the birth defects in the preconception stage. The secondary prevention refers to screening in pregnancy and prenatal diagnosis to early find and intervene the serious fetal birth defects. This article describes the measures of preconception, prenatal and postpartum cares in detail.%  世界卫生组织提出出生缺陷的“三级预防”策略,以减少出生缺陷的发生,其中一级预防指的是孕前阶段综合干预预防出生缺陷,二级预防通过孕期筛查和产前诊断早期发现和早期干预胎儿严重的先天缺陷。该文详细描述了孕前和孕期保健的措施,对产后不可忽略的保健问题提出建议。

  10. Association between intrauterine mild hyperglycemia and post-natal high-fat diet with adiponectin and AMPK pathway genes.

    Science.gov (United States)

    Zhang, Kai; Li, Xin; Zhang, Li; Yang, Huixia

    2016-01-01

    To investigate the mechanisms of maternal-fetal interactions in the setting of gestational diabetes mellitus. We investigated the long-term effects of intrauterine mild hyperglycemia and a postnatal high-fat diet on the glucose metabolism of adult offspring, and explored the role of adiponectin on hepatic gluconeogenesis. Twenty-one pregnant Wistar rats were randomly divided into an intrauterine hyperglycemia group (group D, n = 14) and a control group (group C, n = 7). Offspring were divided into four groups according to intrauterine blood glucose level and post-weaning dietary patterns (high-fat diet groups: DF and CF or normal diet groups: DN and CN, n = 8 per group). The average birth weights of group D offspring were higher than for group C. In the DF rats, low adiponectin mRNA expression in perirenal and epididymal fat was significantly positively correlated with low hepatic AdipoR1 mRNA expression and significantly correlated with high hepatic PEPCK, G-6-Pase, and PGC-1α mRNA levels. In DF rats, hepatic P-AMPK was cytoplasmically located and its level was decreased; in these rats, hepatic CRTC2 was expressed in the nucleus and its level was significantly increased. Our study shows that the dietary structure of offspring has a large influence on the incidence of abnormal glucose tolerance. PMID:26416799

  11. Prenatal pharmacotherapy rescues brain development in a Down's syndrome mouse model.

    Science.gov (United States)

    Guidi, Sandra; Stagni, Fiorenza; Bianchi, Patrizia; Ciani, Elisabetta; Giacomini, Andrea; De Franceschi, Marianna; Moldrich, Randal; Kurniawan, Nyoman; Mardon, Karine; Giuliani, Alessandro; Calzà, Laura; Bartesaghi, Renata

    2014-02-01

    Intellectual impairment is a strongly disabling feature of Down's syndrome, a genetic disorder of high prevalence (1 in 700-1000 live births) caused by trisomy of chromosome 21. Accumulating evidence shows that widespread neurogenesis impairment is a major determinant of abnormal brain development and, hence, of intellectual disability in Down's syndrome. This defect is worsened by dendritic hypotrophy and connectivity alterations. Most of the pharmacotherapies designed to improve cognitive performance in Down's syndrome have been attempted in Down's syndrome mouse models during adult life stages. Yet, as neurogenesis is mainly a prenatal event, treatments aimed at correcting neurogenesis failure in Down's syndrome should be administered during pregnancy. Correction of neurogenesis during the very first stages of brain formation may, in turn, rescue improper brain wiring. The aim of our study was to establish whether it is possible to rescue the neurodevelopmental alterations that characterize the trisomic brain with a prenatal pharmacotherapy with fluoxetine, a drug that is able to restore post-natal hippocampal neurogenesis in the Ts65Dn mouse model of Down's syndrome. Pregnant Ts65Dn females were treated with fluoxetine from embryonic Day 10 until delivery. On post-natal Day 2 the pups received an injection of 5-bromo-2-deoxyuridine and were sacrificed after either 2 h or after 43 days (at the age of 45 days). Untreated 2-day-old Ts65Dn mice exhibited a severe neurogenesis reduction and hypocellularity throughout the forebrain (subventricular zone, subgranular zone, neocortex, striatum, thalamus and hypothalamus), midbrain (mesencephalon) and hindbrain (cerebellum and pons). In embryonically treated 2-day-old Ts65Dn mice, precursor proliferation and cellularity were fully restored throughout all brain regions. The recovery of proliferation potency and cellularity was still present in treated Ts65Dn 45-day-old mice. Moreover, embryonic treatment restored

  12. Type-Based Automated Verification of Authenticity in Asymmetric Cryptographic Protocols

    DEFF Research Database (Denmark)

    Dahl, Morten; Kobayashi, Naoki; Sun, Yunde;

    2011-01-01

    Gordon and Jeffrey developed a type system for verification of asymmetric and symmetric cryptographic protocols. We propose a modified version of Gordon and Jeffrey's type system and develop a type inference algorithm for it, so that protocols can be verified automatically as they are, without an...

  13. Asymmetric catalysis: An enabling science

    OpenAIRE

    Trost, Barry M.

    2004-01-01

    Chirality of organic molecules plays an enormous role in areas ranging from medicine to material science, yet the synthesis of such entities in one enantiomeric form is one of the most difficult challenges. The advances being made stem from the convergence of a broader understanding of theory and how structure begets function, the developments in the interface between organic and inorganic chemistry and, most notably, the organic chemistry of the transition metals, and the continuing advancem...

  14. A case of asymmetrical monocephalus dipygus (tetrapus dibrachius) in a male Holstein calf in Iran

    Science.gov (United States)

    Marzban Abbasabadi, Behrokh; Ahmadzadeh, Aliakbar; Ramezanpour, Shahab; Hajati Ziabari, Amir Reza

    2016-01-01

    Dipygus is a teratological fetus with a double pelvis, genitals, and extremities. Congenital duplications in cattle are rare. Caudal duplication is more common in sheep and pigs while cranial duplications seem to be predominant in cattle. Asymmetric or parasitic conjoined twins consisting of an incomplete twin (parasite) attached to the body of a fully-developed twin (autosite). This report deals with a male Holstein calf with two extra limbs, in the pelvic region which were directed ventrally between the two normal hind limbs. The extra limbs were completely developed in one side and in other side just a bony mass were observed. So classification has been made as asymmetrical attached twins. The genital system was not affected and just one extra kidney-like structure was found. To the authors’ best knowledge, this is the first report of asymmetrical monocephalus dipygus (tetrapus dibrachius) in a male Holstein calf in Iran. PMID:27482365

  15. Asymmetric catalysis in organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, S.D.; Click, D.R.; Grumbine, S.K.; Scott, B.L.; Watkins, J.G.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of the project was to prepare new catalyst systems, which would perform chemical reactions in an enantioselective manner so as to produce only one of the possible optical isomers of the product molecule. The authors have investigated the use of lanthanide metals bearing both diolate and Schiff-base ligands as catalysts for the enantioselective reduction of prochiral ketones to secondary alcohols. The ligands were prepared from cheap, readily available starting materials, and their synthesis was performed in a ''modular'' manner such that tailoring of specific groups within the ligand could be carried out without repeating the entire synthetic procedure. In addition, they have developed a new ligand system for Group IV and lanthanide-based olefin polymerization catalysts. The ligand system is easily prepared from readily available starting materials and offers the opportunity to rapidly prepare a wide range of closely related ligands that differ only in their substitution patterns at an aromatic ring. When attached to a metal center, the ligand system has the potential to carry out polymerization reactions in a stereocontrolled manner.

  16. Asymmetric interaction will facilitate the evolution of cooperation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Explaining the evolution of cooperation remains one of the greatest problems for both biology and social science. The classical theories of cooperation suggest that cooperation equilibrium or evolutionary stable strategy between partners can be maintained through genetic similarity or reciprocity relatedness. These classical theories are based on an assumption that partners interact symmetrically with equal payoffs in a game of cooperation interaction. However, the payoff between partners is usually not equal and therefore they often interact asymmetrically in real cooperative systems. With the Hawk–Dove model, we find that the probability of cooperation between cooperative partners will depend closely on the payoff ratio. The higher the payoff ratio between recipients and cooperative actors, the greater will be the probability of cooperation interaction between involved partners. The greatest probability of conflict between cooperative partners will occur when the payoff between partners is equal. The results show that this asymmetric relationship is one of the key dynamics of the evolution of cooperation, and that pure cooperation strategy (i.e., Nash equilibrium) does not exist in asymmetrical cooperation systems, which well explains the direct conflict observed in almost all of the well documented cooperation systems. The model developed here shows that the cost-to-benefit ratio of cooperation is also negatively correlated with the probability of cooperation interaction. A smaller cost-to-benefit ratio of cooperation might be created by the limited dispersal ability or exit cost of the partners involved, and it will make the punishment of the non-cooperative individuals by the recipient more credible, and therefore make it more possible to maintain stable cooperation interaction.

  17. Design of Asymmetric Peptide Bilayer Membranes.

    Science.gov (United States)

    Li, Sha; Mehta, Anil K; Sidorov, Anton N; Orlando, Thomas M; Jiang, Zhigang; Anthony, Neil R; Lynn, David G

    2016-03-16

    Energetic insights emerging from the structural characterization of peptide cross-β assemblies have enabled the design and construction of robust asymmetric bilayer peptide membranes. Two peptides differing only in their N-terminal residue, phosphotyrosine vs lysine, coassemble as stacks of antiparallel β-sheets with precisely patterned charged lattices stabilizing the bilayer leaflet interface. Either homogeneous or mixed leaflet composition is possible, and both create nanotubes with dense negative external and positive internal solvent exposed surfaces. Cross-seeding peptide solutions with a preassembled peptide nanotube seed leads to domains of different leaflet architecture within single nanotubes. Architectural control over these cross-β assemblies, both across the bilayer membrane and along the nanotube length, provides access to highly ordered asymmetric membranes for the further construction of functional mesoscale assemblies.

  18. δ Meson Effects on Asymmetric Nuclear Matter

    Science.gov (United States)

    Liu, B.; di Toro, M.; Greco, V.

    The impact of a δ meson field (the scalar-isovector channel) on asymmetric nuclear matter is studied within relativistic mean-field (RMF) models with both constant and density dependent (DD) nucleon-meson couplings. The Equation of State (EOS) for asymmetric nuclear matter and the neutron star properties by the different models are compared. We find that the δ-field in the constant coupling scheme leads to a larger repulsion in dense neutron-rich matter and to a definite splitting of proton and neutron effective masses, finally influencing the stability of the neutron stars. A broader analysis of possible δ-field effects is achieved considering also density dependent nucleon-meson coupling. A remarkable effect on the relation between mass and radius for the neutron stars is seen, showing a significant reduction of the radius along with a moderate mass reduction due to the increase of the effective δ coupling in high density regions.

  19. Enhancing molecule fluorescence with asymmetrical plasmonic antennas.

    Science.gov (United States)

    Lu, Guowei; Liu, Jie; Zhang, Tianyue; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gu, Ying; He, Yingbo; Wang, Yuwei; Gong, Qihuang

    2013-07-21

    We propose and justify by the finite-difference time-domain method an efficient strategy to enhance the spontaneous emission of a fluorophore with a multi-resonance plasmonic antenna. The custom-designed asymmetrical antenna consists of two plasmonic nanoparticles with different sizes and is able to couple efficiently to free space light through multiple localized surface plasmon resonances. This design simultaneously permits a large near-field excitation near the antenna as well as a high quantum efficiency, which results in an unusual and significant enhancement of the fluorescence of a single emitter. Such an asymmetrical antenna presents intrinsic advantages over single particle or dimer based antennas made using two identical nanostructures. This promising concept can be exploited in the large domain of light-matter interaction processes involving multiple frequencies.

  20. Applications of Chiral Anions in Asymmetric Catalysis

    OpenAIRE

    Hamilton, Gregory Lawrence

    2011-01-01

    The synthesis of molecules with control over their three-dimensional configuration, known as absolute stereochemistry, is one of the highest goals of synthetic organic chemists. As is so often the case, we strive to reach the facility and efficiency with which Nature achieves this goal. Fortunately, the chemist's imagination allows us to envision nearly unlimited possibilities for new modes of catalysis. In this dissertation, I discuss one branch of asymmetric catalysis that has in a short ti...

  1. New ruthenium catalysts for asymmetric hydrogenation

    OpenAIRE

    Diaz Valenzuela, Maria Belen

    2007-01-01

    A review on catalytic asymmetric hydrogenation of C=O double bonds is presented in the first chapter. Noyori’s pioneering research on ruthenium complexes containing both phosphine and diamine ligands using [i superscript]PrOH and [t superscript]BuOK is described, this system gave impressive highly chemeo-selectivity for C=O bonds and extremely high enantioselectivity for a range of acetophenone derivatives. Numerous groups have been inspired by Noyori’s catalyst of the ty...

  2. Competitive Price and Quality Under Asymmetric Information

    OpenAIRE

    Gerard J. Tellis; Birger Wernerfelt

    1987-01-01

    We present an analysis of equilibrium in markets with asymmetrically informed consumers. Some consumers know both price and quality of all sellers, whereas others know neither but may search among sellers. The equilibrium correlation between price and quality generally increases with the level of information in the market and can be negative when this level is sufficiently small. A meta-analysis of the available empirical studies strongly supports the model's predictions.

  3. Asymmetric inheritance of cytoophidia in Schizosaccharomyces pombe

    OpenAIRE

    Jing Zhang; Lydia Hulme; Ji-Long Liu

    2014-01-01

    ABSTRACT A general view is that Schizosaccharomyces pombe undergoes symmetric cell division with two daughter cells inheriting equal shares of the content from the mother cell. Here we show that CTP synthase, a metabolic enzyme responsible for the de novo synthesis of the nucleotide CTP, can form filamentous cytoophidia in the cytoplasm and nucleus of S. pombe cells. Surprisingly, we observe that both cytoplasmic and nuclear cytoophidia are asymmetrically inherited during cell division. Our t...

  4. Selective Homogeneous Catalysis in Asymmetric Synthesis

    DEFF Research Database (Denmark)

    Fristrup, Peter

    The subject of this thesis is selectivity in homogeneous asymmetric transition metalcatalyzed reactions. Four different reactions within organic chemistry have been studied by kinetic measurements, computational chemistry (modelling) or both of them in parallel. A Hammett study was performed....... A thorough computational study succeeded in explaining the observed results, although other significant results were also obtained during this study. Finally, an intramolecular reaction was studied computationally, and the rate increase observed under phase transfer catalysis conditions could be related...

  5. On asymmetric collisions with large disruption parameters

    International Nuclear Information System (INIS)

    Collisions between a weak electron bunch and a strong positron bunch are studied within a flat model. Electrons are tracked through the transverse space charge field of the positron bunch, and it is shown that positrons in a storage ring may remain stable after asymmetric collisions with a weak electron bunch in spite of large values of the electron disruption parameter. The plasma oscillations that affect collisions with large disruption parameters may be suppressed by properly matching the electrons. 8 refs., 5 figs

  6. Surface segregation of conformationally asymmetric polymer blends

    OpenAIRE

    Stepanow, Semjon; Fedorenko, Andrei A.

    2005-01-01

    We have generalized the Edwards' method of collective description of dense polymer systems in terms of effective potentials to polymer blends in the presence of a surface. With this method we have studied conformationally asymmetric athermic polymer blends in the presence of a hard wall to the first order in effective potentials. For polymers with the same gyration radius $R_g$ but different statistical segment lengths $l_{A}$ and $l_{B}$ the excess concentration of stiffer polymers at the su...

  7. Trapdoor Privacy in Asymmetric Searchable Encryption Schemes

    OpenAIRE

    Delerue Arriaga, Afonso; TANG, QIANG; Ryan, Peter

    2014-01-01

    Asymmetric searchable encryption allows searches to be carried over ciphertexts, through delegation, and by means of trapdoors issued by the owner of the data. Public Key Encryption with Keyword Search (PEKS) is a primitive with such functionality that provides delegation of exact-match searches. As it is important that ciphertexts preserve data privacy, it is also important that trapdoors do not expose the user’s search criteria. The difficulty of formalizing a security model for trapdoor pr...

  8. Legal Dilemmas in Fighting Asymmetrical Conflicts

    Directory of Open Access Journals (Sweden)

    Pnina Sharvit Baruch

    2012-04-01

    Full Text Available What legal rules apply to armed confrontations against non-state elements in areas populated by civilians? What rules apply when the enemy does not honor the basic laws of warfare - does not distinguish itself from the local population, and even uses it for shelter and as a base of operations? This essay, which presents my position on the issue, refers to such confrontations as "asymmetrical conflicts."

  9. Do Daily Retail Gasoline Prices adjust Asymmetrically?

    OpenAIRE

    Bettendorf, Leon; Geest, Stéphanie; Kuper, G.

    2005-01-01

    This paper analyzes adjustments in the Dutch retail gasoline prices. We estimate an error correction model on changes in the daily retail price for gasoline (taxes excluded) for the period 1996-2004 taking care of volatility clustering by estimating an EGARCH model. It turns out the volatility process is asymmetrical: an unexpected increase in the producer price has a larger effect on the variance of the producer price than an unexpected decrease. We do not find evidence for amount asymmetry,...

  10. Asymmetric Information – Adverse Selection Problem

    Directory of Open Access Journals (Sweden)

    Dumitru MARIN

    2007-01-01

    Full Text Available The present paper makes an introduction in the contract theory starting with the definitions of asymmetric information and some of the problems that generate: moral hazard and adverse selection. We provide an insight of the latest empirical studies in adverse selection in different markets. An adverse selection model, based on Rothchild and Stiglitz is also present to give a perspective of the theoretical framework.

  11. OFFICER AND COMMANDER IN ASYMMETRIC WARFARE OPERATIONS

    OpenAIRE

    Giuseppe CAFORIO

    2013-01-01

    Starting from the data of a field research conducted among soldiers with asymmetric warfare experiences from nine different countries, the author seeks to identify and shed light on the various problems that officers with command responsibilities had to face during their missions. A picture emerges of feelings and experiences relating to their first impression upon arriving in the theatre, relations with local armed forces, relations with the local population and local authorities, relations ...

  12. Ultralong distance coupling between asymmetric resonant microcavities

    OpenAIRE

    Shu, Fang-Jie; Zou, Chang-Ling; Chen, Wen-Cong; Sun, Fang-Wen

    2013-01-01

    The ultralong distance coupling between two Asymmetric Resonant Microcavities (ARCs) is studied. Different from traditional short distance tunneling coupling between microcavities, the high efficient free space directional emission and excitation allow ultralong distance energy transfer between ARCs. In this paper, a novel unidirectional emission ARC, which shows directionality I40 = 0.54, is designed for materials of refractive index n = 2.0. Compared with regular whispering gallery microres...

  13. Asymmetric Reversal in Inhomogeneous Magnetic Heterostructures

    OpenAIRE

    Li, Zhi-Pan; Petracic, Oleg; Morales, Rafael; Olamit, Justin; Batlle, Xavier; Liu, Kai; Schuller, Ivan K.

    2006-01-01

    Asymmetric magnetization reversal is an unusual phenomenon in antiferromagnet/ferromagnet (AF/FM) exchange biased bilayers. We investigated this phenomenon in a simple model system experimentally and by simulation assuming inhomogeneously distributed interfacial AF moments. The results suggest that the observed asymmetry originates from the intrinsic broken symmetry of the system, which results in local incomplete domain walls parallel to the interface in reversal to negative saturation of th...

  14. Asymmetric Conditional Volatility in International Stock Markets

    CERN Document Server

    Ferreira, N B; Menezes, R; Ferreira, Nuno B.; Mendes, Diana A.; Menezes, Rui

    2006-01-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the S&P 500, FTSE100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of chan...

  15. Asymmetric nuclear matter equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Bombaci, I.; Lombardo, U. (Dipartimento di Fisica, Universita di Catania, Corso Italia 57, Catania (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania (Italy))

    1991-11-01

    Systematic calculations of asymmetric nuclear matter have been performed in the framework of the Brueckner-Bethe-Goldstone approach in a wide range of both density and asymmetry parameter. The empirical parabolic law fulfilled by the binding energy per nucleon is confirmed by the present results in all the range of the asymmetry parameter values. The predominant role of the {sup 3}{ital S}{sub 1-}{sup 3}{ital D}{sub 1} component of the {ital NN} interaction is elucidated. A linear variation of the proton and neutron single-particle potentials is found as increasing the neutron excess; a deviation from the phenomenological potentials occurs for highly asymmetric matter as an effect of the self-consistency. The present calculations of the incompressibility predict a strong softening of the equation of state going from symmetric to asymmetric nuclear matter. The proton fraction in equilibrium with neutron matter has been determined from the beta-stability condition and its relevance to the superfluidity of neutron stars has been investigated.

  16. Multiple Traveling Salesmen in Asymmetric Metrics

    CERN Document Server

    Friggstad, Zachary

    2011-01-01

    We consider some generalizations of the Asymmetric Traveling Salesman Path problem. Suppose we have an asymmetric metric G = (V,A) with two distinguished nodes s,t. We are also given a positive integer k. The goal is to find k paths of minimum total cost from s to t whose union spans all nodes. We call this the k-Person Asymmetric Traveling Salesmen Path problem (k-ATSPP). Our main result for k-ATSPP is a bicriteria approximation that, for some parameter b >= 1 we may choose, finds between k and k + k/b paths of total length O(b log |V|) times the optimum value of an LP relaxation based on the Held-Karp relaxation for the Traveling Salesman problem. On one extreme this is an O(log |V|)-approximation that uses up to 2k paths and on the other it is an O(k log |V|)-approximation that uses exactly k paths. Next, we consider the case where we have k pairs of nodes (s_1,t_1), ..., (s_k,t_k). The goal is to find an s_i-t_i path for every pair such that each node of G lies on at least one of these paths. Simple appro...

  17. Traceless Synthesis of Asymmetrically Modified Bivalent Nucleosomes.

    Science.gov (United States)

    Lechner, Carolin C; Agashe, Ninad D; Fierz, Beat

    2016-02-18

    Nucleosomes carry extensive post-translational modifications (PTMs), which results in complex modification patterns that are involved in epigenetic signaling. Although two copies of each histone coexist in a nucleosome, they may not carry the same PTMs and are often differently modified (asymmetric). In bivalent domains, a chromatin signature prevalent in embryonic stem cells (ESCs), namely H3 methylated at lysine 4 (H3K4me3), coexists with H3K27me3 in asymmetric nucleosomes. We report a general, modular, and traceless method for producing asymmetrically modified nucleosomes. We further show that in bivalent nucleosomes, H3K4me3 inhibits the activity of the H3K27-specific lysine methyltransferase (KMT) polycomb repressive complex 2 (PRC2) solely on the same histone tail, whereas H3K27me3 stimulates PRC2 activity across tails, thereby partially overriding the H3K4me3-mediated repressive effect. To maintain bivalent domains in ESCs, PRC2 activity must thus be locally restricted or reversed.

  18. Asymmetric Explosions of Thermonuclear Supernovae

    CERN Document Server

    Ghezzi, C R; Horváth, J E

    2004-01-01

    A type Ia supernova explosion starts in a white dwarf as a laminar deflagration at the center of the star and soon several hydrodynamic instabilities (in particular, the Rayleigh-Taylor (R-T) instability) begin to act. In previous work (Ghezzi, de Gouveia Dal Pino, & Horvath 2001), we addressed the propagation of an initially laminar thermonuclear flame in presence of a magnetic field assumed to be dipolar. We were able to show that, within the framework of a fractal model for the flame velocity, the front is affected by the field through the quenching of the R-T instability growth in the direction perpendicular to the field lines. As a consequence, an asymmetry develops between the magnetic polar and the equatorial axis that gives a prolate shape to the burning front. We have here computed numerically the total integrated asymmetry as the flame front propagates outward through the expanding shells of decreasing density of the magnetized white dwarf progenitor, for several chemical compositions, and found...

  19. Synthesis of New Chiral Phosphine Ligands and Their Application in Asymmetric Hydrogenation of Ketones

    Institute of Scientific and Technical Information of China (English)

    XIE Jian-Hua; FU Yu; WANG Li-Xin; ZHOU Qi-Lin

    2004-01-01

    The design of new chiral ligands is the key in the development of transition metal catalyzed asymmetric synthesis. Many chiral diphosphine ligands have been prepared and applied in asymmetric catalytic reactions with excellent enantioselectivities. Among the chiral diphosphine ligands that have been reported, the atropisomeric C2-symmetric phosphines with a biaryl scaffold initiated by Noyori and co-workers with BINAP were found to have the widest application in the transition metal catalyzed reactions. Planar chiral diphosphines based on ferrocene or paracyclophane backbones have also been applied to a number of reactions with a remarkable degree of success. However, the spiro diphosphine compounds, another type of axially chiral ligands, have not been synthesized yet. Recently, we designed chiral phosphoramidite ligands (SIPHOS)containing a 1, 1′-spirobiindane backbone and demonstrated that these ligands can be highly efficient for the Rh-catalyzed asymmetric hydrogenation of functionalized olefins. Especially, in the case of asymmetric hydrogenation of α-arylethenylamines, the spiro monophosphoramidite ligands provided a significantly higher level of enantiocontrol compared to that of the monophosphoramidite ligands derived from BINOL. Herein we present the synthesis of spiro diphosphines (SDP) containing 1,1′-spirobiindane as a new chiral scaffold and their application in the ruthenium-catalyzed asymmetric hydrogenation of simple ketones with high activity (S/C up to 100 000) and excellent enantioselectivity (ee up to 99.5%).

  20. A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes

    Science.gov (United States)

    Han, Yining; Huang, Shanghui; Yan, Tianying

    2014-07-01

    The size of ions significantly influences the electric double layer structure of room temperature ionic liquid (IL) electrolytes and their differential capacitance (Cd). In this study, we extended the mean-field theory (MFT) developed independently by Kornyshev (2007J. Phys. Chem. B 111 5545-57) and Kilic, Bazant, and Ajdari (2007 Phys. Rev. E 75 021502) (the KKBA MFT) to take into account the asymmetric 1:1 IL electrolytes by introducing an additional parameter ξ for the anion/cation volume ratio, besides the ionic compressibility γ in the KKBA MFT. The MFT of asymmetric ions becomes KKBA MFT upon ξ = 1, and further reduces to Gouy-Chapman theory in the γ → 0 limit. The result of the extended MFT demonstrates that the asymmetric ILs give rise to an asymmetric Cd, with the higher peak in Cd occurring at positive polarization for the smaller anionic size. At high potential, Cd decays asymptotically toward KKBA MFT characterized by γ for the negative polarization, and characterized by ξγ for the positive polarization, with inverse-square-root behavior. At low potential, around the potential of zero charge, the asymmetric ions cause a higher Cd, which exceeds that of Gouy-Chapman theory.

  1. Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts.

    Science.gov (United States)

    Wang, Kun; Zhou, Jianfeng; Hamill, Joseph M; Xu, Bingqian

    2014-08-01

    The contact effects of single-molecule break junctions on rectification behaviors were experimentally explored by a systematic control of anchoring groups of 1,4-disubstituted benzene molecular junctions. Single-molecule conductance and I-V characteristic measurements reveal a strong correlation between rectifying effects and the asymmetry in contacts. Analysis using energy band models and I-V calculations suggested that the rectification behavior is mainly caused by asymmetric coupling strengths at the two contact interfaces. Fitting of the rectification ratio by a modified Simmons model we developed suggests asymmetry in potential drop across the asymmetric anchoring groups as the mechanism of rectifying I-V behavior. This study provides direct experimental evidence and sheds light on the mechanisms of rectification behavior induced simply by contact asymmetry, which serves as an aid to interpret future single-molecule electronic behavior involved with asymmetric contact conformation.

  2. Optical color image encryption based on an asymmetric cryptosystem in the Fresnel domain

    Science.gov (United States)

    Chen, Wen; Chen, Xudong

    2011-08-01

    In recent years, optical color image encryption has attracted much attention in the information security field. Some approaches, such as digital holography, have been proposed to encrypt color images, but the previously proposed methods are developed based on optical symmetric cryptographic strategies. In this paper, we apply an optical asymmetric cryptosystem for the color image encryption instead of conventional symmetric cryptosystems. A phase-truncated strategy is applied in the Fresnel domain, and multiple-wavelength and indexed image methods are further employed. The security of optical asymmetric cryptosystem is also analyzed during the decryption. Numerical results are presented to demonstrate the feasibility and effectiveness of the proposed optical asymmetric cryptosystem for color image encryption.

  3. Asymmetric transmission of acoustic waves in a layer thickness distribution gradient structure using metamaterials

    Science.gov (United States)

    Chen, Jung-San; Chang, I.-Ling; Huang, Wan-Ting; Chen, Lien-Wen; Huang, Guan-Hua

    2016-09-01

    This research presents an innovative asymmetric transmission design using alternate layers of water and metamaterial with complex mass density. The directional transmission behavior of acoustic waves is observed numerically inside the composite structure with gradient layer thickness distribution and the rectifying performance of the present design is evaluated. The layer thickness distributions with arithmetic and geometric gradients are considered and the effect of gradient thickness on asymmetric wave propagation is systematically investigated using finite element simulation. The numerical results indicate that the maximum pressure density and transmission through the proposed structure are significantly influenced by the wave propagation direction over a wide range of audible frequencies. Tailoring the thickness of the layered structure enables the manipulation of asymmetric wave propagation within the desired frequency range. In conclusion, the proposed design offers a new possibility for developing directional-dependent acoustic devices.

  4. Analysis of Rolling Pressure in Asymmetrical Rolling Process by Slab Method

    Institute of Scientific and Technical Information of China (English)

    TIAN Yong; GUO Yan-hui; WANG Zhao-dong; WANG Guo-dong

    2009-01-01

    The plane strain asymmetrical rolling was analyzed using slab method. The contact arc was replaced by parabola, and the constant surface friction status was adopted during the analysis. The deformation area was divided into three zones according to the direction of the friction. Then, the three zones were studied, respectively. A rolling force model and a rolling torque model were developed based on the analysis, and they were used to analyze the influence of asymmetrical rolling factors on deformation area and unit pressure if they had good precision which was determined by comparing the calculated results with the measured ones.

  5. High Order Centrifugal Distortion Corrections to Energy Levels of Asymmetric Top Molecules

    Institute of Scientific and Technical Information of China (English)

    LIU Yu-Yan; LIU Xiao-Yong; LIU Hong-Ping; GUO Yuan-Qing; HUANG Guang-Ming; LIN Jie-Li; GAO Hui

    2000-01-01

    High order centrifugal distortion terms have been derived and added to the effective Hamiltonian of asymmetric top molecules. Based on this Hamiltonian, a program in Fortran 77 has been developed for spectral analysis of asymmetric top molecules. The high order centrifugal distortion terms are found to be non-negligible even for the low-lying rotational transitions of molecules, such as Ha 18O, subjected to severe centrifugal distortion effect,and for the high-lying rotational transitions of molecules, such as 14N16O2 subjected to the moderate centrifugal distortion effect.

  6. Direct Asymmetric Aldol Type Reaction with Ethyl Diazoacetate: Stereoselective Synthesis of α, β-Dihydroxy Esters

    Institute of Scientific and Technical Information of China (English)

    LIAO Ming-Yi; YAO Wen-Gang; FENG Hai-Tao; WANG Jian-Bo

    2003-01-01

    @@ Enantioselective aldol condensation under catalytic condition remains a challenging task in modern organic synthesis, and numerous efforts have been directed to this area. In particular, the direct catalytic asymmetric aldol reaction is very attractive considering the requirement of atom efficiency. This has been studied only recently, and several very practical processes have been developed. We have recently initiated a study on the direct asymmetric aldol type reaction with ethyl diazoacetate as nucleophile. Moderate enantioselectivities (65% ~91% ee ) were achieved in the condensation of aldehydes with ethyl diazoacetate catalyzed by the chiral complex of BINOL derivatives-Zr (OBu- t )4. [1

  7. Light-Induced Charge Transport within a Single Asymmetric Nanowire

    Energy Technology Data Exchange (ETDEWEB)

    LIU, CHONG; HWANG, YUN YEONG; JEONG, HOON EIU; YANG, PEIDONG

    2011-01-21

    Artificial photosynthetic systems using semiconductor materials have been explored for more than three decades in order to store solar energy in chemical fuels such as hydrogen. By mimicking biological photosynthesis with two light-absorbing centers that relay excited electrons in a nanoscopic space, a dual-band gap photoelectrochemical (PEC) system is expected to have higher theoretical energy conversion efficiency than a single band gap system. This work demonstrates the vectorial charge transport of photo-generated electrons and holes within a single asymmetric Si/TiO2 nanowire using Kelvin probe force microscopy (KPFM). Under UV illumination, higher surface potential was observed on the n-TiO₂ side, relative to the potential of the p-Si side, as a result of majority carriers’ recombination at the Si/TiO₂ interface. These results demonstrate a new approach to investigate charge separation and transport in a PEC system. This asymmetric nanowire heterostructure, with a dual band gap configuration and simultaneously exposed anode and cathode surfaces represents an ideal platform for the development of technologies for the generation of solar fuels, although better photoanode materials remain to be discovered.

  8. Tunable magnetoresistance in an asymmetrically coupled single-molecule junction

    Science.gov (United States)

    Warner, Ben; El Hallak, Fadi; Prüser, Henning; Sharp, John; Persson, Mats; Fisher, Andrew J.; Hirjibehedin, Cyrus F.

    2015-03-01

    Phenomena that are highly sensitive to magnetic fields can be exploited in sensors and non-volatile memories. The scaling of such phenomena down to the single-molecule level may enable novel spintronic devices. Here, we report magnetoresistance in a single-molecule junction arising from negative differential resistance that shifts in a magnetic field at a rate two orders of magnitude larger than Zeeman shifts. This sensitivity to the magnetic field produces two voltage-tunable forms of magnetoresistance, which can be selected via the applied bias. The negative differential resistance is caused by transient charging of an iron phthalocyanine (FePc) molecule on a single layer of copper nitride (Cu2N) on a Cu(001) surface, and occurs at voltages corresponding to the alignment of sharp resonances in the filled and empty molecular states with the Cu(001) Fermi energy. An asymmetric voltage-divider effect enhances the apparent voltage shift of the negative differential resistance with magnetic field, which inherently is on the scale of the Zeeman energy. These results illustrate the impact that asymmetric coupling to metallic electrodes can have on transport through molecules, and highlight how this coupling can be used to develop molecular spintronic applications.

  9. Msx2 -/- transgenic mice develop compound amelogenesis imperfecta, dentinogenesis imperfecta and periodental osteopetrosis.

    Science.gov (United States)

    Aïoub, M; Lézot, F; Molla, M; Castaneda, B; Robert, B; Goubin, G; Néfussi, J R; Berdal, A

    2007-11-01

    The physiological function of the transcription factor Msx2 in tooth and alveolar bone was analysed using a knock-in transgenic mouse line. In this mouse line, the beta-galactosidase gene was used to disrupt Msx2: thus, beta-galactosidase expression was driven by the Msx2 promoter, but Msx2 was not produced. This allowed to monitor Msx2 expression using a beta-galactosidase assay. Msx2 transgenic mice ubiquitously and continuously expressed the mutated Msx2-nlacZ gene in cells of the complex formed by tooth and alveolar bone. Msx2 -/- homozygous mice displayed a wide spectrum of alterations in tooth eruption and morphology as well as dental and periodontal defects from the first post-natal weeks up to 6 months. These defects culminated with the formation of an odontogenic tumour at the mandibular third molar site. This study suggests that bone resorption is a functional target of Msx2 in the alveolar compartment, since Msx2 was expressed in osteoclasts, with the highest expression levels found in the active sites of bone modelling associated with tooth eruption and root elongation. The RANK osteoclast differentiation pathway was affected in microdissected Msx2 -/- mouse alveolar bone (as inferred by RANK ligand mRNA levels) compared to basal bone and wild-type controls. Decreased alveolar osteoclast activity was observed in Msx2 -/- mice, similar to that seen in osteopetrosis, another condition in which osteoclast activity is impaired and odontogenic tumours form. These data suggest a pleiotropic role for Msx2 in oral bone growth from birth until adult homeostasis. RANK pathway appeared to be modulated by Msx2, in addition to the previously reported modulations of BMP4 and laminin5alpha3 in early tooth development. Non-overlapping Msx1 and Msx2 expression patterns suggested that these two homeogenes play non-redundant roles in skeletal growth, with Msx1 targeting basal bone and Msx2 targeting alveolar bone. This study provides a detailed analysis of the phenotype

  10. The effects of the apoE4 genotype on the developing mouse retina.

    Science.gov (United States)

    Maharshak, Idit; Salomon-Zimri, Shiran; Antes, Ran; Liraz, Ori; Nisgav, Yael; Livnat, Tami; Weinberger, Dov; Colton, Carol A; Solomon, Arieh S; Michaelson, Daniel M

    2016-04-01

    Apolipoprotein E4 (apoE4), the most prevalent genetic risk factor for Alzheimer's disease (AD), is associated with neuronal and vascular impairments. The retina, which is as an extension of the central nervous system (CNS), is a particularly suitable model for studying developmental and functional aspects of the neuronal and vascular systems. This study investigates the apoE4-dependent developmental effects on the retinal vasculature and neuronal systems and on the levels of apoE and the vascular endothelial growth factor (VEGF) in the retina. This was performed utilizing retinas of 4, 7, 12, and of 120-day-old human-apoE4-targeted replacement mice and of corresponding mice that express the AD benign isoform, apoE3. The results obtained revealed retinal vascular pathology in the apoE4 mice, which started on the early post-natal days. This includes transient increase in vascular branching, and vascular buds which are round vascular elements representing sprouting or retracting vessels. These effects peaked and ended during the neonatal period. Examination of the synaptic system utilizing the pre-synaptic marker synaptophysin revealed a significant decrease of retinal synaptic density in the apoE4 mice, which was detectable by post-natal day 12 (P12). These morphological changes are associated with neonatal age-dependent elevation in the apoE levels in both apoE3 and apoE4 retinas which is more profound in the apoE4 mice and a corresponding increase in VEGF levels, which is less profound in the apoE4 mice. Additionally, we observed lower levels of retinal VEGF in the apoE4 mice compared to the apoE3 mice retinas on P12. These results show that apoE4 has a transient vascular effect during retinal development that ends in the neonatal period, which is accompanied by a synaptic effect that begins at the end of the neonatal period. These findings show that the apoE4 genotype can have distinct developmental effects on both the retinal vasculature and on neurons and

  11. A Convenient Method to Construct Chroman Skeleton: Asymmetric Synthesis of (-)-4'-Hydroxy-7-methoxyflavane

    Institute of Scientific and Technical Information of China (English)

    XU, Boyan; XUE, Jijun; ZHANG, Huabing; LI, Ying

    2009-01-01

    The first enantioselective synthesis of a naturally occurring 4'-hydroxy-7-methoxyflavane was developed by an asymmetric reduction and a microwave-assistant aromatic C-O bond formation to construct the benzopyran skele- ton. Key features of this method include its brevity, its preserved stereochemical integrity and two different syn- thetic routes to choose.

  12. A numerical strategy for finite element modeling of frictionless asymmetric vocal fold collision

    DEFF Research Database (Denmark)

    Granados, Alba; Misztal, Marek Krzysztof; Brunskog, Jonas;

    2016-01-01

    . Theoretical background and numerical analysis of the finite-element position-based contact model are presented, along with validation. A novel contact detection mechanism capable to detect collision in asymmetric oscillations is developed. The effect of inexact contact constraint enforcement on vocal fold...

  13. Recent approaches towards the asymmetric synthesis of α,α-disubstituted α-amino acids

    DEFF Research Database (Denmark)

    Vogt, Henning; Brase, S.

    2007-01-01

    The class of alpha,alpha-disubstituted alpha-amino acids has gained considerable attention in the past decades and continues doing so. The ongoing interest in biological and chemical properties of the substance class has inspired the development of many new methodologies for their asymmetric...

  14. Perfluoroalkanesulfonamide Organocatalysts for Asymmetric Conjugate Additions of Branched Aldehydes to Vinyl Sulfones

    Directory of Open Access Journals (Sweden)

    Kosuke Nakashima

    2013-11-01

    Full Text Available Asymmetric conjugate additions of branched aldehydes to vinyl sulfones promoted by sulfonamide organocatalyst 6 or 7 have been developed, allowing facile synthesis of the corresponding adducts with all-carbon quaternary stereocenters in excellent yields with up to 95% ee.

  15. Asymmetric Reprogramming Capacity of Parental Pronuclei in Mouse Zygotes

    Directory of Open Access Journals (Sweden)

    Wenqiang Liu

    2014-03-01

    Full Text Available It has been demonstrated that reprogramming factors are sequestered in the pronuclei of zygotes after fertilization, because zygotes enucleated at the M phase instead of interphase of the first mitosis can support the development of cloned embryos. However, the contribution of the parental pronucleus derived from either the sperm or the oocyte in reprogramming remains elusive. Here, we demonstrate that the parental pronuclei have asymmetric reprogramming capacities and that the reprogramming factors reside predominantly in the male pronucleus. As a result, only female pronucleus-depleted (FPD mouse zygotes can reprogram somatic cells to a pluripotent state and support the full-term development of cloned embryos; male pronucleus-depleted (MPD zygotes fail to support somatic cell reprogramming. We further demonstrate that fusion of an additional male pronucleus into a zygote greatly enhances reprogramming efficiency. Our data provide a clue to further identify critical reprogramming factors in the male pronucleus.

  16. The plasmoid instability during asymmetric inflow magnetic reconnection

    CERN Document Server

    Murphy, Nicholas A; Shen, Chengcai; Lin, Jun; Ni, Lei

    2013-01-01

    Theoretical studies of the plasmoid instability generally assume that the reconnecting magnetic fields are symmetric. We relax this assumption by performing two-dimensional resistive magnetohydrodynamic simulations of the plasmoid instability during asymmetric inflow magnetic reconnection. Magnetic asymmetry modifies the onset, scaling, and dynamics of this instability. Magnetic islands develop preferentially into the weak magnetic field upstream region. Outflow jets from individual X-points impact plasmoids obliquely rather than directly as in the symmetric case. Consequently, deposition of momentum by the outflow jets into the plasmoids is less efficient, the plasmoids develop net vorticity, and shear flow slows down secondary merging between islands. Secondary merging events have asymmetry along both the inflow and outflow directions. Downstream plasma is more turbulent in cases with magnetic asymmetry because islands are able to roll around each other after exiting the current sheet. As in the symmetric c...

  17. Asymmetric-Structure Analysis of Carbon and Energy Markets

    Science.gov (United States)

    Xu, Wei; Cao, Guangxi

    2016-02-01

    This study aimed to investigate the asymmetric structure between the carbon and energy markets from two aspects of different trends (up or down) and volatility-transmission direction using asymmetric detrended cross-correlation analysis (DCCA) cross-correlation coefficient test, multifractal asymmetric DCCA (MF-ADCCA) method, asymmetric volatility-constrained correlation metric and time rate of information-flow approach. We sampled 1283 observations from January 2008 to December 2012 among pairs of carbon and energy markets for analysis. Empirical results show that the (1) asymmetric characteristic from the cross-correlation between carbon and returns in the energy markets is significant, (2) asymmetric cross-correlation between carbon and energy market price returns is persistent and multifractral and (3) volatility of the base assets of energy market returns is more influential to the base asset of the carbon market than that of the energy market.

  18. Asymmetric Synthesis of Both Enantiomers of Disparlure

    Institute of Scientific and Technical Information of China (English)

    王志刚; 郑剑峰; 黄培强

    2012-01-01

    Starting from propargyl alcohol (12), and on the basis of Zhou's modified Sharpless asymmetric epoxidation, the sex pheromone of the Gypsy moth, disparlure (+)-8 and its enantiomer (-)-8 have been synthesized, each in six steps, with overall yields of 29% for (+)-8 and 27% for (-)-8 (ee〉98%). The use of the sequential coupling tactic renders the method flexible, which is applicable to the synthesis of other cis-epoxy pheromones.

  19. Infinite dimensional mixed economies with asymmetric information

    CERN Document Server

    Bhowmik, Anuj

    2011-01-01

    In this paper, we study asymmetric information economies consisting of both non-negligible and negligible agents and having ordered Banach spaces as their commodity spaces. In answering a question of Herv\\'{e}s-Beloso and Moreno-Garc\\'{i}a, we establish a characterization of Walrasian expectations allocations by the veto power of the grand coalition. It is also shown that when an economy contains only negligible agents a Vind's type theorem on the private core with the exact feasibility can be restored. This solves a problem of Pesce.

  20. Quantum optics of lossy asymmetric beam splitters

    CERN Document Server

    Uppu, Ravitej; Tentrup, Tristan B H; Pinkse, Pepijn W H

    2016-01-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  1. Asymmetric chemical reactions by polarized quantum beams

    Science.gov (United States)

    Takahashi, Jun-Ichi; Kobayashi, Kensei

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarized light and spin polarized electrons. Circularly polarized light is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarized light can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarized light from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

  2. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  3. OFFICER AND COMMANDER IN ASYMMETRIC WARFARE OPERATIONS

    Directory of Open Access Journals (Sweden)

    Giuseppe CAFORIO

    2013-01-01

    Full Text Available Starting from the data of a field research conducted among soldiers with asymmetric warfare experiences from nine different countries, the author seeks to identify and shed light on the various problems that officers with command responsibilities had to face during their missions. A picture emerges of feelings and experiences relating to their first impression upon arriving in the theatre, relations with local armed forces, relations with the local population and local authorities, relations with NGOs, relations with other armies, the impact of the rules of engagement (ROEs, training and education, and operational experiences. The paper ends with a discussion of the lessons learned.

  4. The Asymmetric Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    2016-01-01

    are asymmetric: During peak-to-trough periods of investor sentiment (sentiment contractions), high sentiment predicts low future returns for the cross section of speculative stocks and for the market overall, whereas the relationship between sentiment and future returns is positive but relatively weak during......We use the returns on lottery-like stocks and a dynamic factor model to construct a novel index of investor sentiment. This new measure is highly correlated with other behavioral indicators, but more closely tracks speculative episodes. Our main new finding is that the effects of sentiment...... trough-to-peak episodes (sentiment expansions). Overall, these results match theories and anecdotal accounts of investor sentiment....

  5. RHIC operation with asymmetric collisions in 2015

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Aschenauer, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ottavio, T. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Drees, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Laster, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marr, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morris, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Narayan, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shrey, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-07

    To study low-x shadowing/saturation physics as well as other nuclear effects [1], [2], proton-gold (p-Au, for 5 weeks) and proton-Aluminum (p-Al, for 2 weeks) collisions were provided for experiments in 2015 at the Relativistic Heavy Ion Collider (RHIC), with polarized proton beam in the Blue ring and Au/Al beam in the Yellow ring. The special features of the asymmetric run in 2015 will be introduced. The operation experience will be reviewed as well in the report.

  6. Asymmetric Hydrogenation of 3-Substituted Pyridinium Salts.

    Science.gov (United States)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2016-07-01

    The use of an equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N-benzylated 3-substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3 N, a Rh-JosiPhos catalyst reduced a range of pyridinium salts with ee values up to 90 %. The role of the base was elucidated with a mechanistic study involving the isolation of the various reaction intermediates and isotopic labeling experiments. Additionally, this study provided some evidence for an enantiodetermining step involving a dihydropyridine intermediate. PMID:27140832

  7. Quantum optics of lossy asymmetric beam splitters

    Science.gov (United States)

    Uppu, Ravitej; Wolterink, Tom A. W.; Tentrup, Tristan B. H.; Pinkse, Pepijn W. H.

    2016-07-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  8. Massless sunset diagrams in finite asymmetric volumes

    Science.gov (United States)

    Niedermayer, F.; Weisz, P.

    2016-06-01

    This paper discusses the methods and the results used in an accompanying paper describing the matching of effective chiral Lagrangians in dimensional and lattice regularizations. We present methods to compute 2-loop massless sunset diagrams in finite asymmetric volumes in the framework of these regularizations. We also consider 1-loop sums in both regularizations, extending the results of Hasenfratz and Leutwyler for the case of dimensional regularization and we introduce a new method to calculate precisely the expansion coefficients of the 1-loop lattice sums.

  9. Plasma current resonance in asymmetric toroidal systems

    Energy Technology Data Exchange (ETDEWEB)

    Hazeltine, R. D. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Catto, Peter J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 167 Albany Street, Cambridge, Massachusetts 02139 (United States)

    2015-09-15

    The well-known singularity in the magnetic differential equation for plasma current in an asymmetric toroidal confinement system is resolved by including in the pressure tensor corrections stemming from finite Larmor radius. The result provides an estimate of the amplitude of spikes in the parallel current that occur on rational magnetic surfaces. Resolution of the singularity is shown to depend on both the ambipolarity condition—the requirement of zero surface-averaged radial current—and the form of the magnetic differential equation near the rational surface.

  10. Plasmonic photodetectors based on asymmetric nanogap electrodes

    Science.gov (United States)

    Ge, Junyu; Luo, Manlin; Zou, Wanghui; Peng, Wei; Duan, Huigao

    2016-08-01

    Hot electrons excited by plasmon resonance in nanostructure can be employed to enhance the properties of photodetectors, even when the photon energy is lower than the bandgap of the semiconductor. However, current research has seldom considered how to realize the efficient collection of hot electrons, which restricts the responsivity of the device. In this paper, a type of plasmonic photodetector based on asymmetric nanogap electrodes is proposed. Owing to this structure, the device achieves responsivities as high as 0.45 and 0.25 mA/W for wavelengths of 1310 and 1550 nm, respectively. These insights can aid the realization of efficient plasmon-enhanced photodetectors for infrared detection.

  11. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Shinji Yamada

    2010-03-01

    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  12. Security-Preserving Asymmetric Protocol Encapsulation

    OpenAIRE

    Vaudenay, Serge; Phan, Raphael C-W

    2007-01-01

    Query-response based protocols between a client and a server such as SSL, TLS, SSH are asymmetric in the sense that the querying client and the responding server play different roles, and for which there is a need for two-way linkability between queries and responses within the protocol. We are motivated by the observation that though results exist in other related contexts, no provably secure scheme has been applied to the setting of client-server protocols, which differ from conventional co...

  13. Chiral Diamine-catalyzed Asymmetric Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Da-zhen; WU Lu-lu; WANG Yong-mei

    2012-01-01

    A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature.A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes,furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

  14. Quantum optics of lossy asymmetric beam splitters.

    Science.gov (United States)

    Uppu, Ravitej; Wolterink, Tom A W; Tentrup, Tristan B H; Pinkse, Pepijn W H

    2016-07-25

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2×2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers. PMID:27464096

  15. RELATIONSHIP OF TRANSVERSAL ASYMMETRIC FACE AND UNILATERAL POSTERIOR CROSSBITE

    OpenAIRE

    Indah Dwinursanty; Krisnawati Krisnawati; Maria Purbiati

    2006-01-01

    Unilateral posterior crossbite is commonly seen in mixed dentition, but it couldn’t be self corrected. If this condition is not treated properly, it could lead to asymmetric face. Asymmetric face with unilateral posterior crossbite could make the treatment process more difficult. The objective of this study is to find out the relationship between transversal skeletal asymmetry and unilateral posterior crossbite. Patients older than 13 years with skeletal asymmetric face, who had never undergo...

  16. Ofd1 controls dorso-ventral patterning and axoneme elongation during embryonic brain development.

    Directory of Open Access Journals (Sweden)

    Anna D'Angelo

    Full Text Available Oral-facial-digital type I syndrome (OFDI is a human X-linked dominant-male-lethal developmental disorder caused by mutations in the OFD1 gene. Similar to other inherited disorders associated to ciliary dysfunction OFD type I patients display neurological abnormalities. We characterized the neuronal phenotype that results from Ofd1 inactivation in early phases of mouse embryonic development and at post-natal stages. We determined that Ofd1 plays a crucial role in forebrain development, and in particular, in the control of dorso-ventral patterning and early corticogenesis. We observed abnormal activation of Sonic hedgehog (Shh, a major pathway modulating brain development. Ultrastructural studies demonstrated that early Ofd1 inactivation results in the absence of ciliary axonemes despite the presence of mature basal bodies that are correctly orientated and docked. Ofd1 inducible-mediated inactivation at birth does not affect ciliogenesis in the cortex, suggesting a developmental stage-dependent role for a basal body protein in ciliogenesis. Moreover, we showed defects in cytoskeletal organization and apical-basal polarity in Ofd1 mutant embryos, most likely due to lack of ciliary axonemes. Thus, the present study identifies Ofd1 as a developmental disease gene that is critical for forebrain development and ciliogenesis in embryonic life, and indicates that Ofd1 functions after docking and before elaboration of the axoneme in vivo.

  17. Asymmetric and axisymmetric dynamics of tropical cyclones

    Science.gov (United States)

    Persing, J.; Montgomery, M. T.; McWilliams, J. C.; Smith, R. K.

    2013-12-01

    during the 3-D intensification process the convection has not yet organized into annular rings, the azimuthally averaged heating rate and radial gradient thereof is considerably less than that in the AX model. This lack of organization results broadly in a slower intensification rate in the 3-D model and leads ultimately to a weaker mature vortex after 12 days of model integration. While azimuthal mean heating rates in the 3-D model are weaker than those in the AX model, local heating rates in the 3-D model exceed those in the AX model and at times the vortex in the 3-D model intensifies more rapidly than AX. Analyses of the 3-D model output do not support a recent hypothesis concerning the key role of small-scale vertical mixing processes in the upper-tropospheric outflow in controlling the intensification process. In the 3-D model, surface drag plays a particularly important role in the intensification process for the prototype intensification problem on meteorologically relevant timescales by helping foster the organization of convection in azimuth. There is a radical difference in the behaviour of the 3-D and AX simulations when the surface drag is reduced or increased from realistic values. Borrowing from ideas developed in a recent paper, we give a partial explanation for this difference in behaviour. Our results provide new qualitative and quantitative insight into the differences between the asymmetric and symmetric dynamics of tropical cyclones and would appear to have important consequences for the formulation of a fluid dynamical theory of tropical cyclone intensification and mature intensity. In particular, the results point to some fundamental limitations of strict axisymmetric theory and modelling for representing the azimuthally averaged behaviour of tropical cyclones in three dimensions.

  18. Asymmetric and axisymmetric dynamics of tropical cyclones

    Directory of Open Access Journals (Sweden)

    J. Persing

    2013-05-01

    into annular rings, the azimuthally-averaged heating rate and radial gradient thereof is considerably less than that in the AX model. This lack of organization results broadly in a slower intensification rate in the 3-D model and leads ultimately to a weaker mature vortex after 12 days of model integration. While axisymmetric heating rates in the 3-D model are weaker than those in the AX model, local heating rates in the 3-D model exceed those in the AX model and at times the vortex in the 3-D model intensifies more rapidly than AX. Analyses of the 3-D model output do not support a recent hypothesis concerning the key role of small-scale vertical mixing processes in the upper-tropospheric outflow in controlling the intensification process. In the 3-D model, surface drag plays a particularly important role in the intensification process for the prototype intensification problem on meteorologically relevant time scales by helping foster the organization of convection in azimuth. There is a radical difference in the behaviour of the 3-D and AX simulations when the surface drag is reduced or increased from realistic values. Borrowing from ideas developed in a recent paper, we give a partial explanation for this difference in behaviour. Our results provide new qualitative and quantitative insight into the differences between the asymmetric and symmetric dynamics of tropical cyclones and would appear to have important consequences for the formulation of a fluid dynamical theory of tropical cyclone intensification and mature intensity. In particular, the results point to some fundamental limitations of strict axisymmetric theory and modelling for representing the azimuthally-averaged behaviour of tropical cyclones in three dimensions.

  19. Asymmetric transmission: a generic property of lossy periodic interfaces

    CERN Document Server

    Plum, E; Zheludev, N I

    2010-01-01

    Asymmetric transmission of circularly polarized waves is a well-established property of lossy, anisotropic, two-dimensionally chiral patterns. Here we show that asymmetric transmission can be observed for oblique incidence onto any lossy periodically structured plane. Our results greatly expand the range of natural and artificial materials in which directionally asymmetric transmission can be expected making it a cornerstone electromagnetic effect rather than a curiosity of planar chiral metamaterials. Prime candidates for asymmetric transmission at oblique incidence are rectangular arrays of plasmonic spheres or semiconductor quantum dots, lossy double-periodic gratings and planar metamaterial structures.

  20. Quantity Discount Scheme in Supply Chain under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    LI Ji-bin; PENG Zuo-he

    2007-01-01

    Quantity discount scheme plays an important role in supply chain management. The different quantity discount schemes under symmetric (full) information and asymmetric information, are analyzed by using principal-agent and optimal control theory. As a result, the research reveals that the optimal quantity discount solution under symmetric information is a special case of that under asymmetric information. At the same price, the critical value of quantity discount under asymmetric information is much lower than that under asymmetric information. Therefore, this leads to less cost for retailers and smaller profit for their supplier.

  1. Particle identification at an asymmetric B Factory

    International Nuclear Information System (INIS)

    Particle identification systems are an important component of any detector at a high-luminosity, asymmetric B Factory. In particular, excellent hadron identification is required to probe CP violation in B0 decays to CP eigenstates. The particle identification systems discussed below also provide help in separating leptons from hadrons at low momenta. We begin this chapter with a discussion of the physics motivation for providing particle identification, the inherent limitations due to interactions and decays in flight, and the requirements for hermiticity and angular coverage. A special feature of an asymmetric B Factory is the resulting asymmetry in the momentum distribution as a function of polar angle; this will also be quantified and discussed. In the next section the three primary candidates, time-of-flight (TOF), energy loss (dE/dx), and Cerenkov counters, both ring-imaging and threshold, will be briefly described and evaluated. Following this, one of the candidates, a long-drift Cerenkov ring-imaging device, is described in detail to provide a reference design. Design considerations for a fast RICH are then described. A detailed discussion of aerogel threshold counter designs and associated R ampersand D conclude the chapter. 56 refs., 64 figs., 13 tabs

  2. An asymmetric B factory based on PEP

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-01

    In this report we describe a design for a high-luminosity Asymmetric B Factory to be built in the PEP tunnel on the SLAC site. This proposal, a collaborative effort SLAC, LBL, and LLNL, is the culmination of more than two years of effort aimed at the design and construction of an asymmetric e{sup +}e{sup {minus}} collider capable of achieving a luminosity of L = 3 {times} 10{sup 33} cm{sup {minus}2} s{sup {minus}1}. The configuration adopted utilizes two storage rings, and electron ring operating at 9 GeV and a positron ring at 3.1 GeV, each with a circumference of 2200 m. The high-energy ring is an upgrade of the PEP storage ring at SLAC; all PEP magnets and most power supplies will be reused. The upgrade consists primarily of replacing the PEP vacuum chamber and RF system with newly designed versions optimized for the high-current environment of the B Factory. The low-energy ring will be newly constructed and will be situated atop the high-energy ring in the PEP tunnel. Utilities already installed in the PEP tunnel are largely sufficient to operate the two B Factory storage rings.

  3. Asymmetric Twin Representation: the Transfer Matrix Symmetry

    Directory of Open Access Journals (Sweden)

    Anastasia Doikou

    2007-01-01

    Full Text Available The symmetry of the Hamiltonian describing the asymmetric twin model was partially studied in earlier works, and our aim here is to generalize these results for the open transfer matrix. In this spirit we first prove, that the so called boundary quantum algebra provides a symmetry for any generic - independent of the choice of model - open transfer matrix with a trivial left boundary. In addition it is shown that the boundary quantum algebra is the centralizer of the $B$ type Hecke algebra. We then focus on the asymmetric twin representation of the boundary Temperley-Lieb algebra. More precisely, by exploiting exchange relations dictated by the reflection equation we show that the transfer matrix with trivial boundary conditions enjoys the recognized $U_q(sl_2otimes U_i(sl_2$ symmetry. When a non-diagonal boundary is implemented the symmetry as expected is reduced, however again certain familiar boundary non-local charges turn out to commute with the corresponding transfer matrix.

  4. Asymmetric disassembly and robustness in declining networks.

    Science.gov (United States)

    Saavedra, Serguei; Reed-Tsochas, Felix; Uzzi, Brian

    2008-10-28

    Mechanisms that enable declining networks to avert structural collapse and performance degradation are not well understood. This knowledge gap reflects a shortage of data on declining networks and an emphasis on models of network growth. Analyzing >700,000 transactions between firms in the New York garment industry over 19 years, we tracked this network's decline and measured how its topology and global performance evolved. We find that favoring asymmetric (disassortative) links is key to preserving the topology and functionality of the declining network. Based on our findings, we tested a model of network decline that combines an asymmetric disassembly process for contraction with a preferential attachment process for regrowth. Our simulation results indicate that the model can explain robustness under decline even if the total population of nodes contracts by more than an order of magnitude, in line with our observations for the empirical network. These findings suggest that disassembly mechanisms are not simply assembly mechanisms in reverse and that our model is relevant to understanding the process of decline and collapse in a broad range of biological, technological, and financial networks.

  5. Properties of asymmetrically evolved community networks

    Institute of Scientific and Technical Information of China (English)

    Cui Di; Gao Zi-You; Zheng Jian-Feng

    2009-01-01

    This paper studies a simple asymmetrically evolved community network with a combination of preferential at-tachment and random properties. An important issue about community networks is to discover the different utility increments of two nodes, where the utility is introduced to investigate the asymmetrical effect of connecting two nodes. On the other hand, the connection of two nodes in community networks can be classified as two nodes belonging to the same or to different communities. The simulation results show that the model can reproduce a power-law utility distribution P(u)~ u-σ,σ=2+ 1/p, which can be obtained by using mean-field approximation methods. Furthermore, the model exhibits exponential behaviour with respect to small values of a parameter denoting the random effect in our model at the low-utility region and a power-law feature with respect to big values of this parameter at the high-utility region, which is in good agreement with theoretical analysis. This kind of community network can reproduce a unique utility distribution by theoretical and numerical analysis.

  6. An asymmetric B factory based on PEP

    International Nuclear Information System (INIS)

    In this report we describe a design for a high-luminosity Asymmetric B Factory to be built in the PEP tunnel on the SLAC site. This proposal, a collaborative effort SLAC, LBL, and LLNL, is the culmination of more than two years of effort aimed at the design and construction of an asymmetric e+e- collider capable of achieving a luminosity of L = 3 x 1033 cm-2 s-1. The configuration adopted utilizes two storage rings, and electron ring operating at 9 GeV and a positron ring at 3.1 GeV, each with a circumference of 2200 m. The high-energy ring is an upgrade of the PEP storage ring at SLAC; all PEP magnets and most power supplies will be reused. The upgrade consists primarily of replacing the PEP vacuum chamber and RF system with newly designed versions optimized for the high-current environment of the B Factory. The low-energy ring will be newly constructed and will be situated atop the high-energy ring in the PEP tunnel. Utilities already installed in the PEP tunnel are largely sufficient to operate the two B Factory storage rings

  7. Asymmetric transition disks: Vorticity or eccentricity?

    CERN Document Server

    Zsom, A; Ghanbari, J

    2013-01-01

    Context. Transition disks typically appear in resolved millimeter observations as giant dust rings surrounding their young host stars. More accurate observations with ALMA have shown several of these rings to be in fact asymmetric: they have lopsided shapes. It has been speculated that these rings act as dust traps, which would make them important laboratories for studying planet formation. It has been shown that an elongated giant vortex produced in a disk with a strong viscosity jump strikingly resembles the observed asymmetric rings. Aims. We aim to study a similar behavior for a disk in which a giant planet is embedded. However, a giant planet can induce two kinds of asymmetries: (1) a giant vortex, and (2) an eccentric disk. We studied under which conditions each of these can appear, and how one can observationally distinguish between them. This is important because only a vortex can trap particles both radially and azimuthally, while the eccentric ring can only trap particles in radial direction. Method...

  8. Asymmetric EPR entanglement in continuous variable systems

    International Nuclear Information System (INIS)

    Continuous variable entanglement can be produced in nonlinear systems or via the interference of squeezed states. In many optical systems such as parametric down conversion, the production of two perfectly symmetric subsystems is usually assumed when demonstrating the existence of entanglement. This symmetry simplifies the description of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualization of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal beamsplitter ratio for entanglement is dependent on the asymmetries and may not be 50 : 50. To support this theory, we present experimental results showing one particular asymmetric entanglement where a 78 : 22 beamsplitter is optimal for observing entanglement. (paper)

  9. Collocation method for the solution of the neutron transport equation with both symmetric and asymmetric scattering

    Energy Technology Data Exchange (ETDEWEB)

    Morel, J.E.

    1981-01-01

    A collocation method is developed for the solution of the one-dimensional neutron transport equation in slab geometry with both symmetric and polarly asymmetric scattering. For the symmetric scattering case, it is found that the collocation method offers a combination of some of the best characteristics of the finite-element and discrete-ordinates methods. For the asymmetric scattering case, it is found that the computational cost of cross-section data processing under the collocation approach can be significantly less than that associated with the discrete-ordinates approach. A general diffusion equation treating both symmetric and asymmetric scattering is developed and used in a synthetic acceleration algorithm to accelerate the iterative convergence of collocation solutions. It is shown that a certain type of asymmetric scattering can radically alter the asymptotic behavior of the transport solution and is mathematically equivalent within the diffusion approximation to particle transport under the influence of an electric field. The method is easily extended to other geometries and higher dimensions. Applications exist in the areas of neutron transport with highly anisotropic scattering (such as that associated with hydrogenous media), charged-particle transport, and particle transport in controlled-fusion plasmas. 23 figures, 6 tables.

  10. Synthesis of 7,7'-Disubstituted BINAP and Their Application in Asymmetric Catalytic Reaction

    Institute of Scientific and Technical Information of China (English)

    Yuan Wei-Cheng; Liu Hua; Mi Ai-Qiao; Gong Liu-Zhu; Jiang Yao-Zhong

    2004-01-01

    The design of new chiral ligands plays a very important role in the development of transition metal catalyzed asymmetric synthesis. Many chiral diphosphine ligands have been prepared and applied in asymmetric catalytic reactions with excellent enantioselectivities. Among the chiral diphosphine ligands reported, BINAP was found to have been the widest application in the transition metal catalyzed reaction. Recently we have developed a novel oxovanadium (Ⅳ)complex catalyst for the oxidative coupling of naphthol with high enantioselectivity.[1] And then a series of optically pure 7,7'-disubstituted BINOLs were successfully synthesized by using the catalyst,[2] on the basis of above, the 7,7'-disubstituted BINAP ligands ( 1-5 ) were easily prepared from the 7,7'-disubstituted BINOLs with high total yields (up to 64% of 5 steps from the BINOLs ).To demonstrate the efficiency of ligands 1-5, we applied their ruthenium complexes for asymmetric hydrogenation of simple ketones with high activity (S/C up to 5000 ), high converation (up to 100%) and moderate enantioselectivity (ee up to 88.3% ) under mild conditions. In addition, in the asymmetric 1,4-addition of arylboronic acids, these ligands also provide excellent enantioselectivity (ee up to 99%) and yield ( up to 99%).

  11. Turbulent mixed convection in asymmetrically heated vertical channel

    Directory of Open Access Journals (Sweden)

    Mokni Ameni

    2012-01-01

    Full Text Available In this paper an investigation of mixed convection from vertical heated channel is undertaken. The aim is to explore the heat transfer obtained by adding a forced flow, issued from a flat nozzle located in the entry section of a channel, to the up-going fluid along its walls. Forced and free convection are combined studied in order to increase the cooling requirements. The study deals with both symmetrically and asymmetrically heated channel. The Reynolds number based on the nozzle width and the jet velocity is assumed to be 3 103 and 2.104; whereas, the Rayleigh number based on the channel length and the wall temperature difference varies from 2.57 1010 to 5.15 1012. The heating asymmetry effect on the flow development including the mean velocity and temperature the local Nusselt number, the mass flow rate and heat transfer are examined.

  12. Polarised cells, polarised views: Asymmetric cell division in hematopoietic cells.

    Directory of Open Access Journals (Sweden)

    Kim ePham

    2014-02-01

    Full Text Available It has long been recognised that alterations in cell shape and polarity play important roles in coordinating lymphocyte functions. In the last decade a new aspect of lymphocyte polarity, termed Asymmetric Cell Division (ACD, has attracted much attention. ACD has previously been shown to dictate or influence many aspects of development in model organisms such as the worm and the fly, and to be disrupted in disease. Recent observations that ACD also occurs in lymphocytes led to exciting speculations that ACD might influence lymphocyte differentiation and function, and leukaemia. However, dissecting the role that ACD might play in these activities is not straightforward, and the evidence to date for a functional role in lymphocyte fate determination has been controversial. In this review, we discuss the evidence to date for ACD in lymphocytes, and how it might influence lymphocyte fate. We also discuss current gaps in our knowledge, and suggest approaches to definitively test the physiological role of ACD in lymphocytes.

  13. Origins of Asymmetric Magnetization Reversal in Exchange Biased Multilayers

    Science.gov (United States)

    Liu, Yang; Wang, Shuoguo; Li, Yang; Chen, Ning; Liu, Shuai; Li, Minghua; Yu, Guanghua; Department of Materials Physics; Chemistry, University of Science; Technology Beijing Team; State Key Laboratory Of Magnetism, Beijing National LaboratoryCondensed Matter Physics, Institu Team; University of Puerto Rico At Mayaguez Team

    2011-03-01

    Novel asymmetric magnetization reversal behaviors (ARBs) as well as positive exchange bias (EB) are observed by using the alternating gradient force magnetometer (AGM) in both Co/FeMn bilayer with an oblique out-of-plane exchange anisotropy and the Co/FeMn bilayer in which Co layer has a quite heavy thickness. There are two different ARBs, arised from the ferromagnetic and the antiferromagnetic layer respectively under the perpendicular magnetization. Our results show that two intrinsic origins of the ARBs (i.e. the competing anisotropy and the inhomogeneity of the magnetic structure) coexist. Both of them are indispensable for the development of the ARBs in our Co/FeMn multilayers. This work was supported by the National Science Foundation under Grant no. DMR-0821284, NASA under Grant Nos. NNX10AM80H and NNX07AO30A.

  14. Control of Wind Turbines during Symmetrical and Asymmetrical Grid Faults

    DEFF Research Database (Denmark)

    Göksu, Ömer

    grid code requirements, which are targeting to make the WPPs operate in a closer manner to the conventional power plants. Common to most of the grid codes, WPPs are required to stay connected during short-circuit grid faults, and also inject reactive current in order to support the grid voltage...... type wind turbines (WTs), in an AC connected WPP, is investigated and control algorithms are designed for minimum disrupted operation and improved grid support, for both symmetrical and asymmetrical grid faults. WTs’ response with conventional control algorithms is studied regarding the impact...... for the control. This Loss of Synchronism (LOS) situation is investigated based on active and reactive current transfer limits which are derived first time in this thesis, together with stability analysis of the grid synchronization of WTs. Novel control algorithms are developed to generate necessary active...

  15. Very-short-pulse modulator using asymmetric thyristors

    Science.gov (United States)

    Perol, P.

    1984-09-01

    The development of a semiconductor delay-line modulator for a 40-nsec/pulse 10-kHz-repetition-rate coaxial magnetron radar used to monitor airport runway traffic is reported and illustrated with circuit diagrams, output spectra, and photographs. The problems presented by the design specifications are indicated, and the solutions adopted (asymmetric press-packed thyristors and ferrite pulse transformer) are explained. Pulse widths and peak powers with 16 nf of delay line and a 2.5-kV charge at the level of the modulator are found to be 120 nsec and 58 kW without truncation and 40 nsec and 50-51 kW with truncation, the latter corresponding to an efficiency of 17 percent. The pulse leading edges have dI/dt at the transformer primary = 1.8 kA/microsec and dV/dt at the magnetron = 160 kV/microsec.

  16. On Cauchy conditions for asymmetric mixed convection boundary layer flows

    Energy Technology Data Exchange (ETDEWEB)

    Amaouche, Mustapha [Laboratoire de Physique Theorique, Universite de Bejaia (Algeria); Kessal, Mohand [Departement Transport et Equipement Petrolier, Faculte des Hydrocarbures et de la Chimie, Universite de Boumerdes, 35000, Boumerdes (Algeria)

    2003-06-01

    The fundamental question of how and where does an asymmetric mixed convection boundary layer flow around a heated horizontal circular cylinder begin to develop is raised. We first transform the classical boundary layer equations by using an integral method of Karman-Pohlhausen type and obtain two coupled equations governing the evolutions of the dynamic and thermal boundary layers. Because of its global character, the implemented method allows to bypass the difficulty of downstream-upstream interactions. Cauchy conditions characterizing the starting of the boundary layers are found; they are obtained in a surprisingly simple manner for the limiting cases corresponding to Pr=1, Pr{yields}0 and Pr{yields}{infinity}. Otherwise, these conditions can be found by using a prediction correction algorithm. Some numerical experiments are finally performed in order to illustrate the theory. (authors)

  17. Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

    Science.gov (United States)

    Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

    2016-08-01

    The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

  18. The early development of brain white matter: a review of imaging studies in fetuses, newborns and infants.

    Science.gov (United States)

    Dubois, J; Dehaene-Lambertz, G; Kulikova, S; Poupon, C; Hüppi, P S; Hertz-Pannier, L

    2014-09-12

    Studying how the healthy human brain develops is important to understand early pathological mechanisms and to assess the influence of fetal or perinatal events on later life. Brain development relies on complex and intermingled mechanisms especially during gestation and first post-natal months, with intense interactions between genetic, epigenetic and environmental factors. Although the baby's brain is organized early on, it is not a miniature adult brain: regional brain changes are asynchronous and protracted, i.e. sensory-motor regions develop early and quickly, whereas associative regions develop later and slowly over decades. Concurrently, the infant/child gradually achieves new performances, but how brain maturation relates to changes in behavior is poorly understood, requiring non-invasive in vivo imaging studies such as magnetic resonance imaging (MRI). Two main processes of early white matter development are reviewed: (1) establishment of connections between brain regions within functional networks, leading to adult-like organization during the last trimester of gestation, (2) maturation (myelination) of these connections during infancy to provide efficient transfers of information. Current knowledge from post-mortem descriptions and in vivo MRI studies is summed up, focusing on T1- and T2-weighted imaging, diffusion tensor imaging, and quantitative mapping of T1/T2 relaxation times, myelin water fraction and magnetization transfer ratio.

  19. Renal Development and Blood Pressure in Offspring from Dams Submitted to High-Sodium Intake during Pregnancy and Lactation

    Directory of Open Access Journals (Sweden)

    Terezila M. Coimbra

    2012-01-01

    Full Text Available Exposure to an adverse environment in utero appears to programme physiology and metabolism permanently, with long-term consequences for health of the fetus or offspring. It was observed that the offspring from dams submitted to high-sodium intake during pregnancy present disturbances in renal development and in blood pressure. These alterations were associated with lower plasma levels of angiotensin II (AII and changes in renal AII receptor I (AT1 and mitogen-activated protein kinase (MAPK expressions during post natal kidney development. Clinical and experimental evidence show that the renin-angiotensin system (RAS participates in renal development. Many effects of AII are mediated through MAPK pathways. Extracellular signal-regulated protein kinases (ERKs play a pivotal role in cellular proliferation and differentiation. In conclusion, high-sodium intake during pregnancy and lactation can provoke disturbances in renal development in offspring leading to functional and structural alterations that persist in adult life. These changes can be related at least in part with the decrease in RAS activity considering that this system has an important role in renal development.

  20. Histopathological Characterization of Tail Injury and Traumatic Neuroma Development after Tail Docking in Piglets.

    Science.gov (United States)

    Sandercock, D A; Smith, S H; Di Giminiani, P; Edwards, S A

    2016-07-01

    Tail docking of neonatal pigs is widely used as a measure to reduce the incidence of tail biting, a complex management problem in the pig industry. Concerns exist over the long-term consequences of tail docking for possible tail stump pain sensitivity due to the development of traumatic neuromas in injured peripheral nerves. Tail stumps were obtained post mortem from four female pigs at each of 1, 4, 8 and 16 weeks following tail amputation (approximately two-thirds removed) by a gas-heated docking iron on post natal day 3. Tissues were processed routinely for histopathological examination. Non-neural inflammatory and reparative epidermal and dermal changes associated with tissue thickening and healing were observed 1 to 4 months after docking. Mild neutrophilic inflammation was present in some cases, although this and other degenerative and non-neural reparative changes are not likely to have caused pain. Traumatic neuroma and neuromatous tissue development was not observed 1 week after tail docking, but was evident 1 month after tail docking. Over time there was marked nerve sheath and axonal proliferation leading to the formation of neuromata, which were either localized and circumscribed or comprised of multiple axons dispersed within granulation tissue. Four months after tail resection, neuroma formation was still incomplete, with possible implications for sensitivity of the tail stump. PMID:27302763

  1. Wired for behavior: from development to function of innate limbic system circuitry

    Directory of Open Access Journals (Sweden)

    Katie eSokolowski

    2012-04-01

    Full Text Available The limbic system of the brain regulates a number of behaviors that are essential for the survival of all vertebrate species including humans. The limbic system predominantly controls appropriate responses to stimuli with social, emotional or motivational salience, which includes innate behaviors such as mating, aggression and defense. Activation of circuits regulating these innate behaviors begins in the periphery with sensory stimulation (primarily via the olfactory system in rodents, and is then processed in the brain by a set of delineated structures that primarily includes the amygdala and hypothalamus. While the basic neuroanatomy of these connections is well established, much remains unknown about how information is processed within innate circuits and how genetic hierarchies regulate development and function of these circuits. Utilizing innovative technologies including channel rhodopsin-based circuit manipulation and genetic manipulation in rodents, recent studies have begun to answer these central questions. In this article we review the current understanding of how limbic circuits regulate sexually dimorphism and how these circuits are established and shaped during pre- and post-natal development. We also discuss how understanding developmental processes of innate circuit formation may inform behavioral alterations observed in neurodevelopmental disorders, such as autism spectrum disorders, which are characterized by limbic system dysfunction.

  2. Development of circadian rhythms in rat pups exposed to microgravity during gestation.

    Science.gov (United States)

    Hoban-Higgins, T M; Murakami, D M; Tang, I H; Fuller, P M; Fuller, C A

    1999-10-01

    Ten pregnant Sprague Dawley rat dams were exposed to spaceflight aboard the Space Shuttle (STS-70) for gestational days 11-20 (G 11-20; FLT group). Control dams were maintained in either a flight-like (FDS group) or vivarium cage environment (VIV group) on earth. All dams had ad lib access to food and water and were exposed to a light-dark cycle consisting of 12 hours of light (approximately 30 lux) followed by 12 hours of darkness. The dams were closely monitored from G 22 until parturition. All pups were cross-fostered at birth; each foster dam had a litter of 10 pups. Pups remained with their foster dam until post natal day 21 (PN 21). Pup body mass was measured twice weekly. At PN 14 FLT pups had a smaller body mass than did the VIV pups (p < 0.01). Circadian rhythms of body temperature and activity of pups from two FLT dams (n = 8), two FDS dams (n = 9) and two VIV dams (n = 7) were studied starting from age PN 21. All pups had circadian rhythms of temperature and activity at this age. There were no significant differences in rhythms between groups that could be attributed to microgravity exposure. These results indicate that exposure to the microgravity environment of spaceflight during this embryonic development period does not affect the development of the circadian rhythms of body temperature and activity. PMID:11543088

  3. A new convenient asymmetric approach to herbarumin Ⅲ

    Institute of Scientific and Technical Information of China (English)

    Xue Song Chen; Shi Jun Da; Li Hong Yang; Bo Yan Xu; Zhi Xiang Xie; Ying Li

    2007-01-01

    The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbarumin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown's asymmetric allylation, taking modified Julia olefination and Yamaguchi's macro-lactonization as key steps.

  4. Effects of Noise on Asymmetric Bidirectional Controlled Teleportation

    Science.gov (United States)

    Nie, Yi-you; Sang, Ming-huang

    2016-07-01

    We present a scheme for asymmetric bidirectional controlled teleportation via a six-qubit cluster state in noisy environments, which includes the phase-damping and amplitude-damping channels. We analytically derive the fidelities of the asymmetric bidirectional controlled teleportation process in these two noise channels. We show that the fidelities only depend on the initial state and the noisy rate.

  5. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  6. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG; XiaoMing

    2001-01-01

    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

  7. Asymmetric catalytic synthesis of the proposed structure of trocheliophorolide B.

    Science.gov (United States)

    Trost, Barry M; Quintard, Adrien

    2012-09-01

    A concise catalytic asymmetric synthesis of the proposed structure of trocheliophorolide B is reported. The synthetic sequence notably features an asymmetric acetaldehyde alkynylation, a Ru-catalyzed alder-ene reaction, and a Zn-ProPhenol ynone aldol condensation. Comparison with the reported data suggests a misassignment of the natural product structure.

  8. Asymmetric catalytic synthesis of the proposed structure of trocheliophorolide B

    OpenAIRE

    Trost, Barry M.; Quintard, Adrien

    2012-01-01

    A concise catalytic asymmetric synthesis of the proposed structure of Trocheliophorolide B is reported. The synthetic sequence notably features an asymmetric acetaldehyde alkynylation, Ru-catalyzed alder-ene reaction and Zn-ProPhenol ynone aldol condensation. Comparison with the reported data suggests a miss-assignment of the natural product structure.

  9. ASYMMETRIC HYDROSILYLATION CATALYZED BY POLYMER—SUPPORTED THIAZOLIDINE RHODIUM CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    LEIYanohui; LIHong; 等

    1999-01-01

    Asymmetric hydrisilylation catalyzed by polymeric thiazolidine rhodium catalysts was conducted.Almost the same optical yields have been obtained when comb-shaped polymeric ligands and their corresponding monomer complexed rhodium cataltysts were used to asymmetric hydrosilylation of acetophenone.Optical yield of chiral 1-methylbenzyl alcohol reaches as high as 71.5%.Temperature dependence of enantioselective hydrosilylation of acetophenone was discussed.

  10. Extensive Taguchi's Quality Loss Function Based On Asymmetric tolerances

    Institute of Scientific and Technical Information of China (English)

    ZHU Wei; LI Yuan-sheng; LIU Feng

    2004-01-01

    If specification interval is asymmetric, basic specification is the target value of quality characteristics. In this paper Taguchi's quality loss function is applied to describe quality loss based on asymmetric tolerances. The measurement of quality loss which is caused by the deviation of quality characteristics from basic specification is further presented.

  11. Asymmetric group loans, non-assortative matching and adverse selection

    NARCIS (Netherlands)

    Gangopadhyay, Shubhashis; Lensink, Robert

    2014-01-01

    This paper shows that an asymmetric group debt contract, where one borrower co-signs for another, but not vice versa, leads to heterogeneous matching. The analysis suggests that micro finance organizations can achieve the first best by offering asymmetric group contracts. (C) 2014 Elsevier B.V. All

  12. Isospin violating dark matter being asymmetric

    CERN Document Server

    Okada, Nobuchika

    2013-01-01

    The isospin violating dark matter (IVDM) scenario offers an interesting possibility to reconcile conflicting results among direct dark matter search experiments for a mass range around 10 GeV. We consider two simple renormalizable IVDM models with a complex scalar dark matter and a Dirac fermion dark matter, respectively, whose stability is ensured by the conservation of "dark matter number". Although both models successfully work as the IVDM scenario with destructive interference between effective couplings to proton and neutron, the dark matter annihilation cross section is found to exceed the cosmological/astrophysical upper bounds. Then, we propose a simple scenario to reconcile the IVDM scenario with the cosmological/astrophysical bounds, namely, the IVDM being asymmetric. Assuming a suitable amount of dark matter asymmetry has been generated in the early Universe, the annihilation cross section beyond the cosmological/astrophysical upper bound nicely works to dramatically reduce the anti-dark matter rel...

  13. Asymmetric morphology of the propagating jet

    Science.gov (United States)

    Hardee, Philip E.; Norman, Michael L.

    1990-12-01

    Simulations of slab jets propagating in constant atmospheres are reported for a range of jet velocities and Mach numbers. At early times, the jet maintains approximate axisymmetry within a backflowing cocoon. When the jet has penetrated farther into the external medium, the symmetry is broken by sideways oscillation and the leading edge of the jet moves about within a growing lobe. The oscillation results from nonlinear resonant amplification of the initial perturbation by the Kelvin-Helmholtz instability. Finally, the jet flaps chaotically within the growing lobe. The flapping is driven by turbulent vortices in the lobe. The basic picture of Scheuer's (1982) 'dentist's drill' model of the physical processes underlying asymmetric morphologies in radio galaxies is confirmed. The fluid motions in the lobe are found to govern the location of the drill bit. The morphology is time-dependent on relatively short time scales.

  14. Asymmetric Beam Combination for Optical Interferometry

    CERN Document Server

    Monnier, J D

    2001-01-01

    Optical interferometers increasingly use single-mode fibers as spatial filters to convert varying wavefront distortion into intensity fluctuations which can be monitored for accurate calibration of fringe amplitudes. Here I propose using an asymmetric coupler to allow the photometric intensities of each telescope beam to be measured at the same time as the fringe visibility, but without the need for dedicated photometric outputs, which reduce the light throughput in the interferometric channels. In the read-noise limited case often encountered in the infrared, I show that a 53% improvement in signal-to-noise ratio for the visibility amplitude measurement is achievable, when compared to a balanced coupler setup with 50% photometric taps (e.g., the FLUOR experiment). In the Poisson-noise limit appropriate for visible light, the improvement is reduced to only ~8%. This scheme also reduces the cost and complexity of the beam combination since fewer components and detectors are required, and can be extended to mor...

  15. Asymmetric Ferromagnet-Superconductor-Ferromagnet Switch

    Energy Technology Data Exchange (ETDEWEB)

    Cadden-Zimansky, P.; Bazaliy, Ya.B.; Litvak, L.M.; Jiang, J.S.; Pearson, J.; Gu, J.Y.; You, Chun-Yeol; Beasley, M.R.; Bader, S.D.

    2011-11-04

    In layered ferromagnet-superconductor-ferromagnet F{sub 1} /S/F{sub 2} structures, the critical temperature T{sub c} of the superconductors depends on the magnetic orientation of the ferromagnetic layers F{sub 1} and F{sub 2} relative to each other. So far, the experimentally observed magnitude of change in T{sub c} for structures utilizing weak ferromagnets has been 2 orders of magnitude smaller than is expected from calculations. We theoretically show that such a discrepancy can result from the asymmetry of F/S boundaries, and we test this possibility by performing experiments on structures where F{sub 1} and F{sub 2} are independently varied. Our experimental results indicate that asymmetric boundaries are not the source of the discrepancy. If boundary asymmetry is causing the suppressed magnitude of T{sub c} changes, it may only be possible to detect in structures with thinner ferromagnetic layers.

  16. Magnetoresistive system with concentric ferromagnetic asymmetric nanorings

    Energy Technology Data Exchange (ETDEWEB)

    Avila, J. I., E-mail: javila@ulg.ac.be; Tumelero, M. A.; Pasa, A. A.; Viegas, A. D. C. [Laboratório de Filmes Finos e Superfícies (LFFS), Departamento de Física, Universidade Federal de Santa Catarina, CP 476 Florianópolis (Brazil)

    2015-03-14

    A structure consisting of two concentric asymmetric nanorings, each displaying vortex remanent states, is studied with micromagnetic calculations. By orienting in suitable directions, both the asymmetry of the rings and a uniform magnetic field, the vortices chiralities can be switched from parallel to antiparallel, obtaining in this way the analogue of the ferromagnetic and antiferromagnetic configurations found in bar magnets pairs. Conditions on the thickness of single rings to obtain vortex states, as well as formulas for their remanent magnetization are given. The concentric ring structure enables the creation of magnetoresistive systems comprising the qualities of magnetic nanorings, such as low stray fields and high stability. A possible application is as contacts in spin injection in semiconductors, and estimations obtained here of magnetoresistance change for a cylindrical spin injection based device show significant variations comparable to linear geometries.

  17. Distributed Function Computation in Asymmetric Communication Scenarios

    CERN Document Server

    Agnihotri, Samar

    2009-01-01

    We consider the distributed function computation problem in asymmetric communication scenarios, where the sink computes some deterministic function of the data split among N correlated informants. The distributed function computation problem is addressed as a generalization of distributed source coding (DSC) problem. We are mainly interested in minimizing the number of informant bits required, in the worst-case, to allow the sink to exactly compute the function. We provide a constructive solution for this in terms of an interactive communication protocol and prove its optimality. The proposed protocol also allows us to compute the worst-case achievable rate-region for the computation of any function. We define two classes of functions: lossy and lossless. We show that, in general, the lossy functions can be computed at the sink with fewer number of informant bits than the DSC problem, while computation of the lossless functions requires as many informant bits as the DSC problem.

  18. Micropolarity Ramification of Asymmetric Merging Flow

    CERN Document Server

    Siddiqui, Abuzar Abid

    2016-01-01

    The steady, asymmetric and two-dimensional flow of viscous, incompressible micropolar fluid through a rectangular channel with a splitter (parallel to walls) was formulated and simulated numerically. The plane Poiseuille flow was considered far from upstream and downstream of the splitter. The geometric parameter that controls the position of splitter was defined as splitter position parameter. A numerical scheme that comprises a fourth order method followed by special finite-difference method was used to solve the boundary value problem. This numerical scheme transforms the governing equations to system of finite difference equations which we have solved by SOR iterative method. Moreover, the results obtained were further refined and upgraded by the Richardson extrapolation method. The results were compared on different grid sizes as well as with the existing results for symmetric flow of Newtonian fluids. The comparisons were satisfactory. The microrotation effects on the splitter plate were significantly h...

  19. Asymmetric pneumatization of the petrous apex.

    Science.gov (United States)

    Roland, P S; Meyerhoff, W L; Judge, L O; Mickey, B E

    1990-07-01

    Three patients with high-intensity MR signals from one petrous apex, but nonpathologic fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side is believed to have generated the high-intensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologic reasons, in an attempt to establish the frequency of this finding. The literature on MR and CT imaging of the petrous apex and asymmetric pneumatization of the petrous apex is reviewed. PMID:2117735

  20. Asymmetric exclusion processes with shuffled dynamics

    International Nuclear Information System (INIS)

    The asymmetric simple exclusion process (ASEP) with periodic boundary conditions is investigated for shuffled dynamics. In this type of update, in each discrete timestep the particles are updated in a random sequence. Such an update is important for several applications, e.g., for certain models of pedestrian flow in two dimensions. For the ASEP with shuffled dynamics and a related truncated process exact results are obtained for deterministic motion (p = 1). Since the shuffled dynamics is intrinsically stochastic, also this case is nontrivial. For the case of stochastic motion (0 < p < 1) it is shown that, in contrast to all other updates studied previously, the ASEP with shuffled update does not have a product measure steady state. Approximative formulae for the steady-state distribution and fundamental diagram are derived that are in very good agreement with simulation data

  1. Chilly Dark Sectors and Asymmetric Reheating

    CERN Document Server

    Adshead, Peter; Shelton, Jessie

    2016-01-01

    In a broad class of theories, the relic abundance of dark matter is determined by interactions internal to a thermalized dark sector, with no direct involvement of the Standard Model (SM). We point out that these theories raise an immediate cosmological question: how was the dark sector initially populated in the early universe? Motivated in part by the difficulty of accommodating large amounts of entropy carried in dark radiation with cosmic microwave background measurements of the effective number of relativistic species at recombination, $N_{\\mathrm{eff}}$, we aim to establish which admissible cosmological histories can populate a thermal dark sector that never reaches thermal equilibrium with the SM. The minimal cosmological origin for such a dark sector is asymmetric reheating, when the same mechanism that populates the SM in the early universe also populates the dark sector at a lower temperature. Here we demonstrate that the resulting inevitable inflaton-mediated scattering between the dark sector and ...

  2. Asymmetric EPR entanglement in continuous variable systems

    CERN Document Server

    Wagner, Katherine; Armstrong, Seiji; Morizur, Jean-Francois; Lam, Ping Koy; Bachor, Hans-Albert

    2012-01-01

    Continuous variable entanglement can be produced in nonlinear systems or via interference of squeezed states. In many of optical systems, such as parametric down conversion or interference of optical squeezed states, production of two perfectly symmetric subsystems is usually used for demonstrating the existence of entanglement. This symmetry simplifies the description of the concept of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualisation of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal...

  3. Asymmetric effects of monetary policy in Brazil

    Directory of Open Access Journals (Sweden)

    Edilean Kleber da Silva Bejarano Aragón

    2009-06-01

    Full Text Available In this paper, we check whether the effects of monetary policy actions on output in Brazil are asymmetric. Therefore, we estimate Markov-switching models that allow positive and negative shocks to affect the growth rate of output in an asymmetric fashion in expansion and recession states. In general, results show that: i the real effects of negative monetary shocks are larger than those of positive shocks in an expansion; ii in a recession, the real effects of positive and negative shocks are the same; iii there is no evidence of asymmetry between the effects of countercyclical monetary policies; and iv it is not possible to assert that the effects of a positive (or negative shock are dependent upon the phase of the business cycle.Neste trabalho, examinamos se os efeitos das ações de política monetária sobre o produto são assimétricos no Brasil. Para isto, estimamos modelos Markov-switching que permitem que choques positivos e negativos afetem a taxa de crescimento do produto de forma assimétrica nos estados de expansão e recessão econômica. Em geral, os resultados mostram que: i os efeitos reais de choques monetários negativos são maiores do que os de choques positivos em uma expansão; ii em uma recessão, os efeitos reais de choques positivos e negativos são iguais; iii não há evidência de assimetria entre os efeitos de políticas monetárias contracíclicas; iv não se pode afirmar que os efeitos de choques positivos (ou negativos dependem da fase do ciclo econômico.

  4. Asymmetric facial skin viscoelasticity during climacteric aging

    Directory of Open Access Journals (Sweden)

    Piérard GE

    2014-04-01

    Full Text Available Gérald E Piérard,1 Trinh Hermanns-Lê,1 Ulysse Gaspard,2 Claudine Piérard-Franchimont11Laboratory of Skin Bioengineering and Imaging, Department of Clinical Sciences, University of Liège, 2Department of Gynecology and Obstetrics, University Hospital of Liège, Liège, BelgiumBackground: Climacteric skin aging affects certain biophysical characteristics of facial skin. The purpose of the present study was to assess the symmetric involvement of the cheeks in this stage of the aging process.Methods: Skin viscoelasticity was compared on both cheeks in premenopausal and post-menopausal women with indoor occupational activities somewhat limiting the influence of chronic sun exposure. Eighty-four healthy women comprising 36 premenopausal women and 48 early post-menopausal women off hormone replacement therapy were enrolled in two groups. The tensile characteristics of both cheeks were tested and compared in each group. A computerized suction device equipped with a 2 mm diameter hollow probe was used to derive viscoelasticity parameters during a five-cycle procedure of 2 seconds each. Skin unfolding, intrinsic distensibility, biological elasticity, and creep extension were measured.Results: Both biological elasticity and creep extension were asymmetric on the cheeks of the post-menopausal women. In contrast, these differences were more discrete in the premenopausal women.Conclusion: Facial skin viscoelasticity appeared to be asymmetric following menopause. The possibility of asymmetry should be taken into account in future studies of the effects of hormone replacement therapy and any antiaging procedure on the face in menopausal women.Keywords: climacteric aging, biomechanics, photoaging, skin unfolding, biological elasticity, skin tensile properties

  5. Algebraic Davis Decomposition and Asymmetric Doob Inequalities

    Science.gov (United States)

    Hong, Guixiang; Junge, Marius; Parcet, Javier

    2016-09-01

    In this paper we investigate asymmetric forms of Doob maximal inequality. The asymmetry is imposed by noncommutativity. Let {({M}, τ)} be a noncommutative probability space equipped with a filtration of von Neumann subalgebras {({M}_n)_{n ≥ 1}}, whose union {bigcup_{n≥1}{M}_n} is weak-* dense in {{M}}. Let {{E}_n} denote the corresponding family of conditional expectations. As an illustration for an asymmetric result, we prove that for {1 < p < 2} and {x in L_p({M},τ)} one can find {a, b in L_p({M},τ)} and contractions {u_n, v_n in {M}} such that {E}_n(x) = a u_n + v_n b quad and quad max big{ |a|_p,|b|_p big} ≤ c_p |x|_p. Moreover, it turns out that {a u_n} and {v_n b} converge in the row/column Hardy spaces {{H}_p^r({M})} and {{H}_p^c({M})} respectively. In particular, this solves a problem posed by the Defant and Junge in 2004. In the case p = 1, our results establish a noncommutative form of the Davis celebrated theorem on the relation betwe en martingale maximal and square functions in L 1, whose noncommutative form has remained open for quite some time. Given {1 ≤ p ≤ 2}, we also provide new weak type maximal estimates, which imply in turn left/right almost uniform convergence of {{E}_n(x)} in row/column Hardy spaces. This improves the bilateral convergence known so far. Our approach is based on new forms of Davis martingale decomposition which are of independent interest, and an algebraic atomic description for the involved Hardy spaces. The latter results are new even for commutative von Neumann algebras.

  6. The evolution of cooperation in asymmetric systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Explaining the "Tragedy of the Commons" of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.

  7. PEP-II: An asymmetric B factory

    International Nuclear Information System (INIS)

    In this report, the authors have described an updated conceptual design for the high-luminosity Asymmetric B Factory (PEP-II) to be built in the PEP tunnel culmination of more than four years of effort aimed at the design and construction of an asymmetric e+e- collider capable of achieving a luminosity of L = 3 x 1033 cm-2 s-1. All aspects of the conceptual design were scrutinized in March 1991 by a DOE technical review committee chaired by Dr. L. Edward Temple. The design was deemed feasible and capable of achieving its physics goals. Furthermore, the cost estimate, schedule, and management plan for the project were fully endorsed by the committee. This updated conceptual design report captures the technical progress since the March 1991 review and reflects the lower cost estimate corresponding to the improved design. Although the PEP-II design has continued to evolve, no technical scope changes have been made that invalidate the conclusion of the DOE review. The configuration adopted utilizes two storage rings, an electron ring operating at 9 GeV and a positron ring at 3.1 GeV, each with a circumference of 2200 m. The high-energy ring is an upgrade of the PEP storage ring at SLAC; all PEP magnets and most power supplies will be reused. The upgrade consists primarily of replacing the PEP vacuum chamber and RF system with newly designed versions optimized for the high-current environment of PEP-II. The low-energy ring will be newly constructed and will be situated atop the high-energy ring in the PEP tunnel. Utilities already installed in the PEP tunnel are largely sufficient to operate the two PEP-II storage rings

  8. Two-stage solar concentrators based on parabolic troughs: asymmetric versus symmetric designs.

    Science.gov (United States)

    Schmitz, Max; Cooper, Thomas; Ambrosetti, Gianluca; Steinfeld, Aldo

    2015-11-20

    While nonimaging concentrators can approach the thermodynamic limit of concentration, they generally suffer from poor compactness when designed for small acceptance angles, e.g., to capture direct solar irradiation. Symmetric two-stage systems utilizing an image-forming primary parabolic concentrator in tandem with a nonimaging secondary concentrator partially overcome this compactness problem, but their achievable concentration ratio is ultimately limited by the central obstruction caused by the secondary. Significant improvements can be realized by two-stage systems having asymmetric cross-sections, particularly for 2D line-focus trough designs. We therefore present a detailed analysis of two-stage line-focus asymmetric concentrators for flat receiver geometries and compare them to their symmetric counterparts. Exemplary designs are examined in terms of the key optical performance metrics, namely, geometric concentration ratio, acceptance angle, concentration-acceptance product, aspect ratio, active area fraction, and average number of reflections. Notably, we show that asymmetric designs can achieve significantly higher overall concentrations and are always more compact than symmetric systems designed for the same concentration ratio. Using this analysis as a basis, we develop novel asymmetric designs, including two-wing and nested configurations, which surpass the optical performance of two-mirror aplanats and are comparable with the best reported 2D simultaneous multiple surface designs for both hollow and dielectric-filled secondaries.

  9. A forecast of energy demand in Japan considering asymmetric price elasticities

    International Nuclear Information System (INIS)

    By estimating the past energy demand function by sector and types of energy in Japan, the existence of asymmetric price elasticities in most the functions was confirmed. As part of the study, a simple energy and economy model was also constructed to compare future energy demand between the cases with symmetric or asymmetric price elasticities. Results show that future energy demand with asymmetric price elasticities is greater than that with symmetric price elasticities. This result is attributed to the fact that in the asymmetric case, past maximum prices are the most significant factors and price effects will not work unless future energy prices exceed past maximum levels. One of the important implications of this study, i.e. the effect on controlling carbon dioxide emissions, is highlighted. It is pointed out that since price elasticities are small, a high rate of carbon tax is needed to decrease carbon dioxide emissions; meaning that the carbon tax should be high enough for future energy prices to exceed the historical maximum levels. The model developed in this study does not incorporate the substitution between fuels, it is, therefore, not suitable for the further quantitative analysis of the carbon tax. While the study does not deny the applicability of the econometric approach to greenhouse gas analysis, it does point to the an importance of being conscious of the limits of the econometric approach. 7 refs., 4 tabs., 3 figs, 1 appendix

  10. Physics and design issues of asymmetric storage ring colliders as B-factories

    International Nuclear Information System (INIS)

    This paper concentrates on generic R ampersand D and design issues of asymmetric colliders via a specific example, namely a 9 GeV x 3 GeV collider based on PEP at SLAC. An asymmetric e+-e- collider at the Y(4s) and with sufficiently high luminosity (1033-1034 cm-2 s-1) offers the possibility of studying mixing, rare decays, and CP violation in the B bar B meson system, as well as ''beautiful'' tau-charm physics, and has certain qualitative advantages from detection and machine design points of view. These include: the energy constraint; clean environment (∼25% B+B-, B0 bar B0); large cross section (1 nb); vertex reconstruction (from the time development of space-time separated B and bar B decays due to moving center-of-mass); reduced backgrounds; greatest sensitivity to CP violation in B → CP eigenstate; the possibility of using higher collision frequencies, up to 100 MHz, in a head-on colliding mode using magnetic separation. It is estimated that for B → ΨKs, an asymmetric collider has an advantage equivalent to a factor of five in luminosity relative to a symmetric one. There are, however, questions with regard to the physics of the asymmetric beam-beam coulomb interaction that may limit the intrinsic luminosity and the possibility of realizing the small beam pipes necessary to determine the vertices. 16 refs., 2 figs

  11. Formation of Dominance Relationships via Strategy Updating in an Asymmetric Hawk-Dove Game

    OpenAIRE

    Grewal, Jasvir K.; Hall, Cameron L.; Porter, Mason A.; Dawkins, Marian S

    2013-01-01

    We develop a model to describe the development of dominance relations between social animals as they use past experiences to inform future interactions. Using the game-theoretic framework of a Hawk-Dove game with asymmetric resource-holding potentials (RHPs), we derive a simple model that describes the social interactions of animals that compete for resources. We then consider a game-playing strategy in which animals acquire information about their RHP asymmetry from the results of their prev...

  12. Special Issue of "Asymmetric Synthesis"%Special Issue of "Asymmetric Synthesis"

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Organic chemistry exploring the world at a molecu- lar level remains essential for our society in the 21st century. Asymmetric synthesis, particularly those em- ploying catalytic approach, is one of the most important research fields in organic synthesis providing chiral compounds in an enantiopure form. The latter is critical since the two enantiomers of one chiral compound, in many cases, have a different response in biological sys- tems. The huge markets of non-racemic chiral com- pounds as synthetic intermediates, pharmaceuticals,

  13. Childhood asymmetrical labium majus enlargement sonographic and MR imaging appearances

    International Nuclear Information System (INIS)

    Childhood asymmetrical labium majus enlargement (CALME) has been described sparsely in recent surgery, pathology, pediatric and gynecology literature; however, no comprehensive description from a radiology perspective has been developed. The purpose of this case series is to describe the imaging findings of CALME and to review the current understanding of this recently described clinical entity with regard to clinical presentation, pathophysiology, differential diagnosis and treatment options. This is a retrospective analysis of 3 girls, ages 5-7 years, who presented for imaging evaluation with subsequent pathologically proven CALME. Each child's clinical history, length of symptoms, imaging appearance and pathological findings were reviewed. All three girls presented with unilateral enlargement of the labium majus (two right-side, one left-side) with no history of trauma or other inciting cause. Two girls had painless labial enlargement that was recognized for weeks, and one had similar symptoms for 1 year prior to presentation. One girl was evaluated initially with sonography, and all three children underwent MR imaging. Sonographic evaluation showed asymmetrical labial enlargement without a definable mass. In each girl, the MR imaging findings were characterized by relatively ill-defined T1-weighted hypointense signal, T2-weighted hypo- to isointense signal with interspersed hyperintense septae, and heterogeneous patchy and feathery strands of enhancement on post-contrast imaging. Biopsy from each child showed benign fibrous tissue with intervening mature fibroadipose tissue, vessels and nerves without findings of inflammation or neoplasia. The MR imaging appearance of CALME is consistent. Recognition and appreciation of this unique pediatric entity by the radiologist may be essential for appropriate diagnosis and can help to guide therapy. Current preferred treatment approach is conservative. (orig.)

  14. Childhood asymmetrical labium majus enlargement sonographic and MR imaging appearances

    Energy Technology Data Exchange (ETDEWEB)

    Gokli, Ami; Neuman, Jeremy; Lukse, Ruby; Koshy, June [Staten Island University Hospital, Department of Radiology, Staten Island, NY (United States); Kong, Fanyi [Staten Island University Hospital, Department of Pathology, Staten Island, NY (United States); Laor, Tal [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2016-05-15

    Childhood asymmetrical labium majus enlargement (CALME) has been described sparsely in recent surgery, pathology, pediatric and gynecology literature; however, no comprehensive description from a radiology perspective has been developed. The purpose of this case series is to describe the imaging findings of CALME and to review the current understanding of this recently described clinical entity with regard to clinical presentation, pathophysiology, differential diagnosis and treatment options. This is a retrospective analysis of 3 girls, ages 5-7 years, who presented for imaging evaluation with subsequent pathologically proven CALME. Each child's clinical history, length of symptoms, imaging appearance and pathological findings were reviewed. All three girls presented with unilateral enlargement of the labium majus (two right-side, one left-side) with no history of trauma or other inciting cause. Two girls had painless labial enlargement that was recognized for weeks, and one had similar symptoms for 1 year prior to presentation. One girl was evaluated initially with sonography, and all three children underwent MR imaging. Sonographic evaluation showed asymmetrical labial enlargement without a definable mass. In each girl, the MR imaging findings were characterized by relatively ill-defined T1-weighted hypointense signal, T2-weighted hypo- to isointense signal with interspersed hyperintense septae, and heterogeneous patchy and feathery strands of enhancement on post-contrast imaging. Biopsy from each child showed benign fibrous tissue with intervening mature fibroadipose tissue, vessels and nerves without findings of inflammation or neoplasia. The MR imaging appearance of CALME is consistent. Recognition and appreciation of this unique pediatric entity by the radiologist may be essential for appropriate diagnosis and can help to guide therapy. Current preferred treatment approach is conservative. (orig.)

  15. Asymmetric electrochemical supercapacitor, based on polypyrrole coated carbon nanotube electrodes

    International Nuclear Information System (INIS)

    Highlights: • Polypyrrole (PPy) coated multiwalled carbon nanotubes (MWCNT) were prepared. • New method is based on the use of new electrochemically active dopants for PPy. • The dopans provided dispersion of MWCNT and promoted PPy coating formation. • Symmetric PPy–MWCNT supercapacitors showed high capacitance and low resistance. • Asymmetric PPy–MWCNT/VN–MWCNT devices and modules allowed larger voltage window. - Abstract: Conductive polypyrrole (PPy) polymer – multiwalled carbon nanotubes (MWCNT) composites were synthesized using sulfanilic acid azochromotrop (SPADNS) and sulfonazo III sodium salt (CHR-BS) as anionic dopants for chemical polymerization of PPy. The composites were tested for application in electrodes of electrochemical supercapacitors (ES). Sedimentation tests, electrophoretic deposition experiments and Fourier transform infrared spectroscopy (FTIR) investigations showed that strong adsorption of anionic CHR-BS on MWCNT provided MWCNT dispersion. The analysis of scanning and transmission electron microscopy data demonstrated that the use of CHR-BS allowed the formation of PPy coatings on MWCNT. As a result, the composites, prepared using CHR-BS, showed higher capacitance, compared to the composites, prepared using SPADNS. The electrodes, containing MWCNT, coated with PPy showed a capacitance of 179 F g−1 for active mass loading of 10 mg cm−2, good capacitance retention at scan rates in the range of 2–100 mV s−1 and excellent cyclic stability. Asymmetric ES devices, containing positive PPy–MWCNT electrodes and negative vanadium nitride (VN)–MWCNT electrodes showed significant improvement in energy storage performance, compared to the symmetric ES due to the larger voltage window. The low impedance and high capacitance of the individual cells paved the way to the development of modules with higher voltage, which showed good electrochemical performance

  16. On the wake flow of asymmetrically beveled trailing edges

    Science.gov (United States)

    Guan, Yaoyi; Pröbsting, Stefan; Stephens, David; Gupta, Abhineet; Morris, Scott C.

    2016-05-01

    Trailing edge and wake flows are of interest for a wide range of applications. Small changes in the design of asymmetrically beveled or semi-rounded trailing edges can result in significant difference in flow features which are relevant for the aerodynamic performance, flow-induced structural vibration and aerodynamically generated sound. The present study describes in detail the flow field characteristics around a family of asymmetrically beveled trailing edges with an enclosed trailing-edge angle of 25° and variable radius of curvature R. The flow fields over the beveled trailing edges are described using data obtained by particle image velocimetry (PIV) experiments. The flow topology for different trailing edges was found to be strongly dependent on the radius of curvature R, with flow separation occurring further downstream as R increases. This variation in the location of flow separation influences the aerodynamic force coefficients, which were evaluated from the PIV data using a control volume approach. Two-point correlations of the in-plane velocity components are considered to assess the structure in the flow field. The analysis shows large-scale coherent motions in the far wake, which are associated with vortex shedding. The wake thickness parameter yf is confirmed as an appropriate length scale to characterize this large-scale roll-up motion in the wake. The development in the very near wake was found to be critically dependent on R. In addition, high-speed PIV measurements provide insight into the spectral characteristics of the turbulent fluctuations. Based on the time-resolved flow field data, the frequency range associated with the shedding of coherent vortex pairs in the wake is identified. By means of time-correlation of the velocity components, turbulent structures are found to convect from the attached or separated shear layers without distinct separation point into the wake.

  17. Examining the Cultural Leadership Behaviors of Schoo l Principal s within the Context of Symmetric and Asymmetric School Culture

    Directory of Open Access Journals (Sweden)

    Betül BALKAR

    2015-08-01

    Full Text Available The aim of this study is to determine the opinions of teachers on contributions of school principals’ cultural leadership behaviors to forming symmetric and asymmetric culture. The participants of the study consisted of 27 secondary school teachers working in Gaziantep province. Data of the study were collected through semi - structured interviews and analyzed through content analysis. Contributions of each cultural leader ship behavior to symmetric and asymmetric culture types were determined by taking relations between cultural leadership behaviors and symmetric and asymmetric cultures into consideration in the process of content analysis. According to the findings of the study ; supporting development of teachers and reflecting developments and innovations on schools are among the cultural leadership behaviors contributing to forming asymmetric culture at schools. Interpreting tasks and missions of school and ensuring neces sary environment for keeping social values alive at schools are among the cultural leadership behaviors contributing to forming symmetric culture at schools. Based on the results of the study, it is suggested that school principals should follow developmen ts in educational issues and transfer these developments into school practices. They should place more importance on supporting innovative behaviors of teachers in order to create asymmetric culture at schools.

  18. Stability Improvement of High-Pressure-Ratio Turbocharger Centrifugal Compressor by Asymmetric Flow Control—Part I: Non-Axisymmetrical Flow in Centrifugal Compressor

    OpenAIRE

    Yang, Mingyang; Zheng, Xinqian; Zhang, Yangjun; Bamba, Takahiro; Tamaki, Hideaki; Huenteler, Joern; Li, Zhigang

    2012-01-01

    This is Part I of a two-part paper documenting the development of a novel asymmetric flow control method to improve the stability of a high-pressure-ratio turbocharger centrifugal compressor. Part I focuses on the nonaxisymmetrical flow in a centrifugal compressor induced by the nonaxisymmetrical geometry of the volute while Part II describes the development of an asymmetric flow control method to avoid the stall on the basis of the characteristic of nonaxisymmetrical flow. To understand the ...

  19. Experimental investigation of symmetric and asymmetric heating of pressure tube under accident conditions for Indian PHWR

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Ashwini K., E-mail: ashwinikumaryadav@gmail.com [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667 (India); Majumdar, P., E-mail: pmajum@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Kumar, Ravi, E-mail: ravikfme@iitr.ernet.in [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667 (India); Chatterjee, B., E-mail: barun@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Gupta, Akhilesh, E-mail: akhilfme@iitr.ernet.in [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667 (India); Lele, H.G., E-mail: hglele@barc.gov.in [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Circumferential temperature gradient for asymmetric heat-up was 400 Degree-Sign C. Black-Right-Pointing-Pointer At same pressure ballooning initiates at lower temperature in asymmetrical heat-up. Black-Right-Pointing-Pointer At 1 MPa ballooning initiated at 408 Degree-Sign C and with expansion rate of 0.005 mm/s. Black-Right-Pointing-Pointer At 2 MPa ballooning initiation at 330 Degree-Sign C and with expansion rate of 0.0056 mm/s. Black-Right-Pointing-Pointer For symmetrical heat-up strain rate was 10 times faster than asymmetric heat-up. - Abstract: In pressurized heavy water reactor (PHWR), under postulated scenario of small break Loss of Coolant Accident (LOCA) coincident with the failure of Emergency Core Cooling System (ECCS), a situation may arise under which reduction in mass flow rate of coolant through individual reactor channel can lead to stratified flow. Such stratified flow condition creates partial uncover of fuel bundle, which creates a circumferential temperature gradient over PT. The present investigation has been carried out to study thermo-mechanical behaviour of PT under asymmetric heating conditions for a 220 MWe PHWR. A 19-pin fuel simulator has been developed in which preferential heating of elements could be done by supplying power to the selected pins. The asymmetric heating of PT has been carried out at pressure 2 MPa and 1 MPa, respectively, by supplying power to upper region heating elements thus creating an half filled stratified flow conditions. The temperature difference up to 425 Degree-Sign C has been observed along top to bottom periphery of PT. A comparison is made between thermo-mechanical behaviour of PT under asymmetrical and symmetrical heat-up, expected from a large break LOCA condition. The radial expansion rate during symmetrical heating is found to be much faster as compared to that for asymmetric ballooning of PT at the same internal pressure. Integrity of PT is found to be

  20. Asymmetric bias in user guided segmentations of brain structures.

    Science.gov (United States)

    Maltbie, Eric; Bhatt, Kshamta; Paniagua, Beatriz; Smith, Rachel G; Graves, Michael M; Mosconi, Matthew W; Peterson, Sarah; White, Scott; Blocher, Joseph; El-Sayed, Mohammed; Hazlett, Heather C; Styner, Martin A

    2012-01-16

    Brain morphometric studies often incorporate comparative hemispheric asymmetry analyses of segmented brain structures. In this work, we present evidence that common user guided structural segmentation techniques exhibit strong left-right asymmetric biases and thus fundamentally influence any left-right asymmetry analyses. In this study, MRI scans from ten pediatric subjects were employed for studying segmentations of amygdala, globus pallidus, putamen, caudate, and lateral ventricle. Additionally, two pediatric and three adult scans were used for studying hippocampus segmentation. Segmentations of the sub-cortical structures were performed by skilled raters using standard manual and semi-automated methods. The left-right mirrored versions of each image were included in the data and segmented in a random order to assess potential left-right asymmetric bias. Using shape analysis we further assessed whether the asymmetric bias is consistent across subjects and raters with the focus on the hippocampus. The user guided segmentation techniques on the sub-cortical structures exhibited left-right asymmetric volume bias with the hippocampus displaying the most significant asymmetry values (porigin of this asymmetric bias is considered to be based in laterality of visual perception; therefore segmentations with any degree of user interaction contain an asymmetric bias. The aim of our study is to raise awareness in the neuroimaging community regarding the presence of the asymmetric bias and its influence on any left-right hemispheric analyses. We also recommend reexamining previous research results in the light of this new finding. PMID:21889995

  1. Simulation of Chaos in Asymmetric Nonlinear Chua's Circuit

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-fei; QIAO Shu-tong; JIANG Jian-guo

    2008-01-01

    In order to describe practical chaotic systems exactly, we presented a simple modified Chua's circuit,which contains an asymmetric nonlinear resistive element. Mathematical analysis was made, and simulation study was performed by MATLAB. By varying the value of linear resistor in the circuit, rich variety dynamical behaviors were observed, such as DC equilibrium point, Hopf bifurcation, period-doubling bifurcation,single-scroll strange attractor, periodic windows, and asymmetric double-scroll strange attractor. The extreme sensitivity in the state trajectory with respect to the initial conditions was exhibited; the special characteristic of asymmetric nonlinear Chua's circuit was found also.

  2. The Dualism of Asymmetric Information in Agricultural Insurance

    Directory of Open Access Journals (Sweden)

    Xuemei Yang

    2013-07-01

    Full Text Available Asymmetric information objectively exists in the insurance market, especially in agricultural insurance, which has a great impact on the insurance contract and market operation. This paper designs two game models to analyse the dualism of asymmetric information in agricultural insurance and its reasons of forming. We find that, the particularity of agricultural production, the agricultural risk diversification and the benefits’ spillover of the agricultural insurance are the main causes of asymmetric information. Therefore, this paper puts forward that establishment of appropriate agricultural insurance mode, optimization of insurance policy design and increasing investment in science and technology, increasing farmers’ insurance consciousness and establishing supervision system

  3. Generic approach for synthesizing asymmetric nanoparticles and nanoassemblies

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yugang; Hu, Yongxing

    2015-05-26

    A generic route for synthesis of asymmetric nanostructures. This approach utilizes submicron magnetic particles (Fe.sub.3O.sub.4--SiO.sub.2) as recyclable solid substrates for the assembly of asymmetric nanostructures and purification of the final product. Importantly, an additional SiO.sub.2 layer is employed as a mediation layer to allow for selective modification of target nanoparticles. The partially patched nanoparticles are used as building blocks for different kinds of complex asymmetric nanostructures that cannot be fabricated by conventional approaches. The potential applications such as ultra-sensitive substrates for surface enhanced Raman scattering (SERS) have been included.

  4. Asymmetric Swiss-cheese brane-worlds

    Science.gov (United States)

    Gergely, László Á.; Képíró, Ibolya

    2007-07-01

    We study a brane-world cosmological scenario with local inhomogeneities represented by black holes. The brane is asymmetrically embedded into the bulk. The black strings/cigars penetrating the Friedmann brane generate a Swiss-cheese-type structure. This universe forever expands and decelerates, as its general relativistic analogue. The evolution of the cosmological fluid, however, can proceed along four branches, two allowed to have positive energy density, and one of them having the symmetric embedding limit. On this branch a future pressure singularity can arise for either (a) a difference in the cosmological constants of the cosmological and black hole brane regions or (b) a difference in the left and right bulk cosmological constants. While behaviour (a) can be avoided by a redefinition of the fluid variables, (b) establishes a critical value of the asymmetry over which the pressure singularity occurs. We introduce the pressure singularity censorship which bounds the degree of asymmetry in the bulk cosmological constant. We also show as a model-independent generic feature that the asymmetry source term due to the bulk cosmological constant increases in the early universe. In order to obey the nucleosynthesis constraints, the brane tension should be constrained therefore both from below and from above. With the maximal degree of asymmetry obeying the pressure singularity censorship, the higher limit is ten times the lower limit. The degree of asymmetry allowed by present cosmological observations is, however, much less, pushing the upper limit to infinity.

  5. ASYMMETRICALLY SECURED EGMP OVER MANET’S

    Directory of Open Access Journals (Sweden)

    Sayed Mohammed Raja

    2013-06-01

    Full Text Available Group communications are significant in Mobile Ad hoc Networks (MANET. Multicast is an wellorganized technique for applying group communications. Yet, it is interesting to implement effective andaccessible multicast in MANET due to the effort in group member management and multicasting of packets forwarding in an active topology. We suggest a Asymmetrically Secured novel Efficient Geographic Multicast Protocol (EGMP. EGMP uses a practical-zone-based arrangement to implement accessible and effective groupmember management. A network-wide zone-based bi-directional tree is made to attain more well-organized member management and multicast delivery. The location information is used to monitor the zone structure, multicast tree building and multicast packets forwarding, which capably reduce the overhead for route finding and tree structure maintenance. Some approaches have been suggested to further improvement in the efficiency of the protocol, for example, presenting the concept of zone depth for construction an ideal tree structure and adding the position search of group of members with the ordered group member management. To switch empty zone problem met by most routing protocols using a zone structure. Finally, we plan a pattern to switch the security problem faced by the multicasting. The scalability and the productivity of EGMP are assessed through simulations and quantitative analysis. Our results prove that EGMP has great packet delivery ratio, and low control overhead, and is accessible to both group size and network size. EGMP has expressively lower control overhead, data transmission overhead, and multicast group joining delay.

  6. Asymmetric sensory reweighting in human upright stance.

    Directory of Open Access Journals (Sweden)

    David Logan

    Full Text Available To investigate sensory reweighting as a fundamental property of sensor fusion during standing, we probed postural control with simultaneous rotations of the visual scene and surface of support. Nineteen subjects were presented with pseudo-random pitch rotations of visual scene and platform at the ankle to test for amplitude dependencies in the following conditions: low amplitude vision: high amplitude platform, low amplitude vision: low amplitude platform, and high amplitude vision: low amplitude platform. Gain and phase of frequency response functions (FRFs to each stimulus were computed for two body sway angles and a single weighted EMG signal recorded from seven muscles. When platform stimulus amplitude was increased while visual stimulus amplitude remained constant, gain to vision increased, providing strong evidence for inter-modal reweighting between vision and somatosensation during standing. Intra-modal reweighting of vision was also observed as gains to vision decreased as visual stimulus amplitude increased. Such intra-modal and inter-modal amplitude dependent changes in gain were also observed in muscular activity. Gains of leg segment angle and muscular activity relative to the platform, on the other hand, showed only intra-modal reweighting. That is, changing platform motion amplitude altered the responses to both visual and support surface motion whereas changing visual scene motion amplitude did not significantly affect responses to support surface motion, indicating that the sensory integration scheme between somatosensation (at the support surface and vision is asymmetric.

  7. Evacuation dynamics of asymmetrically coupled pedestrian pairs

    CERN Document Server

    Müller, Frank

    2016-01-01

    We propose and analyze extended floor field cellular automaton models for evacuation dynamics of inhomogeneous pedestrian pairs which are coupled by asymmetric group interactions. Such pairs consist of a leader, who mainly determines the couple's motion and a follower, who has a defined tendency to follow the leader. Examples for such pairs are mother and child or two siblings of different age. We examine the system properties and compare them to the case of a homogeneous crowd. We find a strong impact on evacuation times for the regime of strong pair coupling due to the occurrence of a clogging phenomenon. In addition we obtain a non-trivial dependence of evacuation times on the followers' coupling to the static floor field, which carries the information of the shortest way to the exit location. In particular we find that systems with fully passive followers, who are solely coupled to their leaders, show lower evacuation times than homogeneous systems where all pedestrians have an equal tendency to move towa...

  8. ADMonium: Asymmetric Dark Matter Bound State

    CERN Document Server

    Bi, Xiao-Jun; Ko, P; Li, Jinmian; Li, Tianjun

    2016-01-01

    We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. Therefore, the ADM can form bound state due to its large self-interaction via $X$ mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with $b\\bar b$. Of particular interest, our setup nicely explains the recent di-photon anomaly at 750 GeV via the events from ${\\rm ADMonium}\\ra 2X(\\ra e^+e^-)$, where the electrons are identified as ...

  9. Asymmetric translation between multiple representations in chemistry

    Science.gov (United States)

    Lin, Yulan I.; Son, Ji Y.; Rudd, James A., II

    2016-03-01

    Experts are more proficient in manipulating and translating between multiple representations (MRs) of a given concept than novices. Studies have shown that instruction using MR can increase student understanding of MR, and one model for MR instruction in chemistry is the chemistry triplet proposed by Johnstone. Concreteness fading theory suggests that presenting concrete representations before abstract representations can increase the effectiveness of MR instruction; however, little work has been conducted on varying the order of different representations during instruction and the role of concreteness in assessment. In this study, we investigated the application of concreteness fading to MR instruction and assessment in teaching chemistry. In two experiments, undergraduate students in either introductory psychology courses or general chemistry courses were given MR instruction on phase changes using different orders of presentation and MR assessment questions based on the representations in the chemistry triplet. Our findings indicate that the order of presentation based on levels of concreteness in MR chemistry instruction is less important than implementation of comprehensive MR assessments. Even after MR instruction, students display an asymmetric understanding of the chemical phenomenon on the MR assessments. Greater emphasis on MR assessments may be an important component in MR instruction that effectively moves novices toward more expert MR understanding.

  10. Computation in dynamically bounded asymmetric systems.

    Directory of Open Access Journals (Sweden)

    Ueli Rutishauser

    2015-01-01

    Full Text Available Previous explanations of computations performed by recurrent networks have focused on symmetrically connected saturating neurons and their convergence toward attractors. Here we analyze the behavior of asymmetrical connected networks of linear threshold neurons, whose positive response is unbounded. We show that, for a wide range of parameters, this asymmetry brings interesting and computationally useful dynamical properties. When driven by input, the network explores potential solutions through highly unstable 'expansion' dynamics. This expansion is steered and constrained by negative divergence of the dynamics, which ensures that the dimensionality of the solution space continues to reduce until an acceptable solution manifold is reached. Then the system contracts stably on this manifold towards its final solution trajectory. The unstable positive feedback and cross inhibition that underlie expansion and divergence are common motifs in molecular and neuronal networks. Therefore we propose that very simple organizational constraints that combine these motifs can lead to spontaneous computation and so to the spontaneous modification of entropy that is characteristic of living systems.

  11. Phase transitions in warm, asymmetric nuclear matter

    International Nuclear Information System (INIS)

    A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is then applied to the liquid-gas phase transition that may occur in the warm, dilute matter produced in energetic heavy-ion collisions. In asymmetric matter, instabilities that produce a liquid-gas phase separation arise from fluctuations in the proton concentration (chemical instability), rather than from fluctuations in the baryon density (mechanical instability)

  12. Asymmetric vector mesons produced in nuclear collisions

    CERN Document Server

    Dremin, I M

    2016-01-01

    It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continuum states in Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction ...

  13. Barbed congruence of the asymmetric chi calculus

    Institute of Scientific and Technical Information of China (English)

    DONG Xiao-ju; FU Yu-xi

    2006-01-01

    The chi calculus is a model of mobile processes. It has evolved from the pi-calculus with motivations from simplification and communication-as-cut-elimination. This paper studies the chi calculus in the framework incorporating asymmetric communication. The major feature of the calculus is the identification of two actions:x/x and τ. The investigation on the barbed bisimilarity shows how the property affects the observational theory.Based on the definition of the barbed bisimilarity, the simulation properties of the barbed bisimilarity are studied. It shows that the algebraic properties of the barbed bisimilarity have changed greatly compared with the chi calculus. Although the definition of the barbed bisimilarity is very simple, the property of closeness under contexts makes it difficult to understand the barbed bisimilarity directly. Therefore an open style definition of the barbed bisimilarity is given, which is a context free description of barbed bisimilarity. Its definition is complex,but it is a well-behaved relation for it coincides with the barbed bisimilarity. It also helps to build an axiomatization system for the barbed congruence. Besides the axioms for the strong barbed bisimilarity, the paper proposes a new tau law and four new update laws for the barbed congruence. Both the operational and algebraic properties of the enriched calculus improve the understanding of the bisimulation behaviors of the model.

  14. Mid-infrared tunable optical polarization converter composed of asymmetric graphene nanocrosses.

    Science.gov (United States)

    Cheng, Hua; Chen, Shuqi; Yu, Ping; Li, Jianxiong; Deng, Li; Tian, Jianguo

    2013-05-01

    We present a mid-IR highly tunable optical polarization converter composed of asymmetric graphene nanocrosses. It can convert linearly polarized light to circularly and elliptically polarized light or exhibit a giant optical activity at different wavelengths. The transmitted wavelength and polarization states can also be dynamically tuned by varying the Fermi energy of graphene, without reoptimizing and refabricating the nanostructures. This offers a further step in developing a controllable polarization converter. PMID:23632554

  15. Catalytic Asymmetric [4 + 1] Annulation of Sulfur Ylides with Copper-Allenylidene Intermediates.

    Science.gov (United States)

    Wang, Qiang; Li, Tian-Ren; Lu, Liang-Qiu; Li, Miao-Miao; Zhang, Kai; Xiao, Wen-Jing

    2016-07-13

    The first copper-catalyzed asymmetric decarboxylative [4 + 1] cycloaddition of propargylic carbamates and sulfur ylides was successfully developed. This strategy led to a series of chiral indolines with synthetically flexible alkyne groups in good yields and with high enantio- and diastereoselectivities (up to 99% yield, 98% ee, and >95:5 dr). A possible mechanism and stereoinduction mode with copper-allenylidenes were proposed as the possible dipolar intermediate. PMID:27355096

  16. Novel Phases and Finite-Size Scaling in Two-Species Asymmetric Diffusive Processes

    OpenAIRE

    Leung, Kwan-tai

    1994-01-01

    We study a stochastic lattice gas of particles undergoing asymmetric diffusion in two dimensions. Transitions between a low-density uniform phase and high-density non-uniform phases characterized by localized or extended structure are found. We develop a mean-field theory which relates coarse-grained parameters to microscopic ones. Detailed predictions for finite-size ($L$) scaling and density profiles agree excellently with simulations. Unusual large-$L$ behavior of the transition point para...

  17. Mo-catalyzed asymmetric olefin metathesis in target-oriented synthesis: Enantioselective synthesis of (+)-africanol

    Science.gov (United States)

    Weatherhead, Gabriel S.; Cortez, G. A.; Schrock, Richard R.; Hoveyda, Amir H.

    2004-01-01

    Catalytic asymmetric ring-opening metathesis (AROM) provides an efficient method for the synthesis of a variety of optically enriched small organic molecules that cannot be easily prepared by alternative methods. The development of Mo-catalyzed AROM transformations that occur in tandem with ring-closing metathesis are described. The utility of the Mo-catalyzed AROM/ring-closing metathesis is demonstrated through an enantioselective approach to the synthesis of (+)-africanol. PMID:15056762

  18. Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters

    Directory of Open Access Journals (Sweden)

    Wen-Bin Yi

    2012-08-01

    Full Text Available A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE and used for the next round of reaction without further purification.

  19. Reflection Asymmetric Relativistic Mean Field Approach and Its Application to the Octupole Deformed Nucleus 226Ra

    Institute of Scientific and Technical Information of China (English)

    GENG Li-Sheng; MENG Jie; Toki Hiroshi

    2007-01-01

    A reflection asymmetric relativistic mean field (RAS-RMF) approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-centre harmonic-oscillator potential.The efficiency and reliability of the RAS-RMF approach are demonstrated in its application to the well-known octupole deformed nucleus 226Ra and the available data, including the binding energy and the deformation parameters, are well reproduced.

  20. Chiral Brønsted Acids for Asymmetric Organocatalysis

    Science.gov (United States)

    Kampen, Daniela; Reisinger, Corinna M.; List, Benjamin

    Chiral Brønsted acid catalysis is an emerging area of organocatalysis. Since the pioneering studies of the groups of Akiyama and Terada in 2004 on the use of chiral BINOL phosphates as powerful Brønsted acid catalysts in asymmetric Mannich-type reactions, numerous catalytic asymmetric transformations involving imine activation have been realized by means of this catalyst class, including among others Friedel-Crafts, Pictet-Spengler, Strecker, cycloaddition reactions, transfer hydrogenations, and reductive aminations. More recently, chiral BINOL phosphates found application in multicomponent and cascade reactions as for example in an asymmetric version of the Biginelli reaction. With the introduction of chiral BINOL-derived N-triflyl phosphoramides in 2006, asymmetric Brønsted acid catalysis is no longer restricted to reactive substrates. Also certain carbonyl compounds can be activated through these stronger Brønsted acid catalysts. In dealing with sensitive substrate classes, chiral dicarboxylic acids proved of particular value.

  1. Asymmetric Aldol Reaction with Formaldehyde: a Challenging Process.

    Science.gov (United States)

    Meninno, Sara; Lattanzi, Alessandra

    2016-08-01

    The asymmetric aldol reaction with formaldehyde is a fundamental carbon-carbon bond-forming reaction in organic synthesis, as well as in the quest of the origin of life, as it is thought to have been the first "molecular brick" involved in the synthetic path to complex sugars. Products of aldol reactions, i.e., the β-hydroxy carbonyl compounds, are versatile building blocks used to access a great variety of functionalised molecules. The employment of formaldehyde, as a C1 symmetric electrophile, in aldol reactions can be likely considered the most challenging, yet simplest, process to introduce a hydroxymethyl group in an asymmetric fashion. In this account, an overview of the progress achieved in the asymmetric metal- and organocatalysed aldol reaction, using readily available formalin or paraformaldehyde sources, is illustrated. Our recent contribution to this area, with the application of asymmetric hydroxymethylation in cascade processes for the synthesis of γ-butyrolactones, is also shown. PMID:27328802

  2. Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, T.D. [Washington Univ., Seattle, WA (United States). Dept. of Physics; Broniowski, W. [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-01

    We analyze the chiral limit in dense isoptin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter. (author). 20 refs.

  3. A novel and practical asymmetric synthesis of dapoxetine hydrochloride

    Directory of Open Access Journals (Sweden)

    Yijun Zhu

    2015-12-01

    Full Text Available A novel and practical asymmetric synthesis of dapoxetine hydrochloride by using the chiral auxiliary (S-tert-butanesulfinamide was explored. The synthesis was concise, mild, and easy to perform. The overall yield and stereoselectivity were excellent.

  4. Asymmetric Synthesis of ( - ) -(2R, 3R, 6S ) -Irnigaine

    Institute of Scientific and Technical Information of China (English)

    MA, Nan; MA, Da-Wei

    2003-01-01

    Asymmetric synthesis of irnigaine was achieved starting from an enantiopure β-amino ester 5 using the condensation of amino alcohol 2 with acetylacetone and the subsequent intramolecular cyclization as the key steps.

  5. Asymmetric periflexural exanthema: A report in an adult patient

    Directory of Open Access Journals (Sweden)

    Zawar V

    2003-11-01

    Full Text Available Asymmetric periflexural exanthem (APE is a distinctive exanthem, probably viral in origin. It is largely a disease of childhood and is uncommon in adults. We report an adult man presenting with the typical clinical findings of APE.

  6. Asymmetric dynamic phase holographic grating in nematic liquid crystal

    Science.gov (United States)

    Ren, Chang-Yu; Shi, Hong-Xin; Ai, Yan-Bao; Yin, Xiang-Bao; Wang, Feng; Ding, Hong-Wei

    2016-09-01

    A new scheme for recording a dynamic phase grating with an asymmetric profile in C60-doped homeotropically aligned nematic liquid crystal (NLC) was presented. An oblique incidence beam was used to record the thin asymmetric dynamic phase holographic grating. The diffraction efficiency we achieved is more than 40%, exceeding the theoretical limit for symmetric profile gratings. Both facts can be explained by assuming that a grating with an asymmetric saw-tooth profile is formed in the NLC. Finally, physical mechanism and mathematical model for characterizing the asymmetric phase holographic grating were presented, based on the photo-refractive-like (PR-like) effect. Project supported by the Science and Technology Programs of the Educational Committee of Heilongjiang Province, China (Grant No. 12541730) and the National Natural Science Foundation of China (Grant No. 61405057).

  7. Vertical Control and Parallel Trade under Asymmetric Information

    Directory of Open Access Journals (Sweden)

    Alessandro Avenali

    2015-05-01

    profits from the manufacturer to the wholesaler. Therefore, in R&D-intensive industries, such as pharmaceuticals, policy makers should anticipate the likely consequences of PT under asymmetric information on the long-run incentives to innovate.

  8. Asymmetric H-D exchange reactions of fluorinated aromatic ketones

    KAUST Repository

    Zhao, Yujun

    2012-01-01

    Chiral bicyclic guanidine catalyzes the asymmetric H-D exchange reactions. Up to 30% ee was achieved. DFT calculations were employed to elucidate and explain the origin of the reaction\\'s stereoselectivity. © 2012 The Royal Society of Chemistry.

  9. Abundance of Asymmetric Dark Matter in Brane World Cosmology

    Science.gov (United States)

    Abdusattar, Haximjan; Iminniyaz, Hoernisa

    2016-09-01

    Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle. We show the indirect detection signal constraints can be used to such model only when the cross section and the 5-dimensional Planck mass scale are in appropriate values. Supported by the National Natural Science Foundation of China under Grant No. 11365022

  10. Asymmetric wave transmission in a diatomic acoustic/elastic metamaterial

    Science.gov (United States)

    Li, Bing; Tan, K. T.

    2016-08-01

    Asymmetric acoustic/elastic wave transmission has recently been realized using nonlinearity, wave diffraction, or bias effects, but always at the cost of frequency distortion, direction shift, large volumes, or external energy. Based on the self-coupling of dual resonators, we propose a linear diatomic metamaterial, consisting of several small-sized unit cells, to realize large asymmetric wave transmission in low frequency domain (below 1 kHz). The asymmetric transmission mechanism is theoretically investigated, and numerically verified by both mass-spring and continuum models. This passive system does not require any frequency conversion or external energy, and the asymmetric transmission band can be theoretically predicted and mathematically controlled, which extends the design concept of unidirectional transmission devices.

  11. Polarization dependent switching of asymmetric nanorings with a circular field

    Directory of Open Access Journals (Sweden)

    Nihar R. Pradhan

    2016-01-01

    Full Text Available We experimentally investigated the switching from onion to vortex states in asymmetric cobalt nanorings by an applied circular field. An in-plane field is applied along the symmetric or asymmetric axis of the ring to establish domain walls (DWs with symmetric or asymmetric polarization. A circular field is then applied to switch from the onion state to the vortex state, moving the DWs in the process. The asymmetry of the ring leads to different switching fields depending on the location of the DWs and direction of applied field. For polarization along the asymmetric axis, the field required to move the DWs to the narrow side of the ring is smaller than the field required to move the DWs to the larger side of the ring. For polarization along the symmetric axis, establishing one DW in the narrow side and one on the wide side, the field required to switch to the vortex state is an intermediate value.

  12. Analysis of liposomes using asymmetrical flow field-flow fractionation

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Decker, Christiane; Fahr, Alfred

    2012-01-01

    Liposomes composed of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol were analyzed by asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering. In addition to evaluation of fractionation conditions (flow conditions, sample mass, carrier liquid...

  13. Corporate underinvestment in the presence of symmetric and asymmetric information

    OpenAIRE

    Hartl, Johannes

    2012-01-01

    Underinvestment and Asymmetric Information: Underinvestment arises when a firm passes up a profitable investment opportunity. The first part of the dissertation deals with corporate underinvestment in the presence of asymmetric information. Specifically, the seminal model by Myers and Majluf (1984) is presented in detail. In this three-period model, corporations have the opportunity to undertake a profitable new investment project, but have to finance it by issuing new shares. There is asy...

  14. Large deviation function of the partially asymmetric exclusion process.

    Science.gov (United States)

    Lee, D S; Kim, D

    1999-06-01

    The large deviation function obtained recently by Derrida and Lebowitz [Phys. Rev. Lett. 80, 209 (1998)] for the totally asymmetric exclusion process is generalized to the partially asymmetric case in the scaling limit. The asymmetry parameter rescales the scaling variable in a simple way. The finite-size corrections to the universal scaling function and the universal cumulant ratio are also obtained to the leading order. PMID:11969632

  15. Equation of state and phase transitions in asymmetric nuclear matter

    OpenAIRE

    Kolomietz, V. M.; Sanzhur, A. I.; Shlomo, S.; Firin, S. A.

    2001-01-01

    The structure of the 3-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter is studied within the thermal Thomas-Fermi approximation. Special attention is paid to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium. We derive the condition of existence of the regime of retrograde condensation at the boiling of the asymmetric nuclear matter. We have performed calculation...

  16. Catalytic Methods in Asymmetric Synthesis Advanced Materials, Techniques, and Applications

    CERN Document Server

    Gruttadauria, Michelangelo

    2011-01-01

    This book covers advances in the methods of catalytic asymmetric synthesis and their applications. Coverage moves from new materials and technologies to homogeneous metal-free catalysts and homogeneous metal catalysts. The applications of several methodologies for the synthesis of biologically active molecules are discussed. Part I addresses recent advances in new materials and technologies such as supported catalysts, supports, self-supported catalysts, chiral ionic liquids, supercritical fluids, flow reactors and microwaves related to asymmetric catalysis. Part II covers advances and milesto

  17. Absolute Asymmetric Synthesis: The Origin, Control, and Amplification of Chirality

    OpenAIRE

    Delden, Richard A. van; Feringa, Bernard

    1999-01-01

    One of the fundamental and intriguing aspects of life is the homochirality of the essential molecules. From the early days of stereochemistry, the origin of chirality in biological systems has been a challenge to the chemical sciences and numerous theories and experiments have been reported. Despite the great progress in asymmetric synthesis, there are only a few genuine absolute asymmetric syntheses known today. Novel approaches based on the interplay of molecular biology, organic chemistry,...

  18. Project financing versus corporate financing under asymmetric information

    OpenAIRE

    Anton Miglo

    2008-01-01

    In recent years financing through the creation of an independent project company or financing by non-recourse debt has become an important part of corporate decisions. Shah and Thakor (JET, 1987) argue that project financing can be optimal when asymmetric information exists between firm's insiders and market participants. In contrast to that paper, we provide an asymmetric information argument for project financing without relying on corporate taxes, costly information production or an assump...

  19. Entangling two oscillators with arbitrary asymmetric initial states

    OpenAIRE

    Yang, Chui-Ping; Su, Qi-Ping; Zheng, Shi-Biao; Nori, Franco; Han, Siyuan

    2016-01-01

    A Hamiltonian is presented, which can be used to convert any asymmetric state $|\\varphi \\rangle_{a}|\\phi \\rangle_{b}$ of two oscillators $a$ and $b$ into an entangled state. Furthermore, with this Hamiltonian and local operations only, two oscillators, initially in any asymmetric initial states, can be entangled with a third oscillator. The prepared entangled states can be engineered with an arbitrary degree of entanglement. A discussion on the realization of this Hamiltonian is given. Numeri...

  20. The Rationality of EIA Forecasts under Symmetric and Asymmetric Loss

    OpenAIRE

    Auffhammer, Maximilian

    2005-01-01

    The United States Energy Information Administration publishes annual forecasts of nationally aggregated energy consumption, production, prices, intensity and GDP. These government issued forecasts often serve as reference cases in the calibration of simulation and econometric models, which climate and energy policy are based on. This study tests for rationality of published EIA forecasts under symmetric and asymmetric loss. We find strong empirical evidence of asymmetric loss for oil, coal a...

  1. Circular Motion of Asymmetric Self-Propelling Particles

    Science.gov (United States)

    Kümmel, Felix; ten Hagen, Borge; Wittkowski, Raphael; Buttinoni, Ivo; Eichhorn, Ralf; Volpe, Giovanni; Löwen, Hartmut; Bechinger, Clemens

    2013-05-01

    Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft lithography and study their circular motion on a substrate and near channel boundaries. Our experimental observations are in full agreement with a theory of Brownian dynamics for asymmetric self-propelled particles, which couples their translational and orientational motion.

  2. Cooperative Mechanism of Supply Chain Under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    郭敏; 王红卫; 瞿坦

    2003-01-01

    The cooperative mechanism is one main issue in the decentralized supply chain system, especially in an asymmetric information structure. We analyze the non-cooperative game behavior of a 2-echelon distribution supply chain, compare the results with the system optimal solution, and give the supplier dominated cooperative mechanisms. We also analyze the validity of our contract under the asymmetric retailers' holding cost information and give some useful conclusions.

  3. Signal transfer within a cultured asymmetric cortical neuron circuit

    Science.gov (United States)

    Isomura, Takuya; Shimba, Kenta; Takayama, Yuzo; Takeuchi, Akimasa; Kotani, Kiyoshi; Jimbo, Yasuhiko

    2015-12-01

    Objective. Simplified neuronal circuits are required for investigating information representation in nervous systems and for validating theoretical neural network models. Here, we developed patterned neuronal circuits using micro fabricated devices, comprising a micro-well array bonded to a microelectrode-array substrate. Approach. The micro-well array consisted of micrometre-scale wells connected by tunnels, all contained within a silicone slab called a micro-chamber. The design of the micro-chamber confined somata to the wells and allowed axons to grow through the tunnels bidirectionally but with a designed, unidirectional bias. We guided axons into the point of the arrow structure where one of the two tunnel entrances is located, making that the preferred direction. Main results. When rat cortical neurons were cultured in the wells, their axons grew through the tunnels and connected to neurons in adjoining wells. Unidirectional burst transfers and other asymmetric signal-propagation phenomena were observed via the substrate-embedded electrodes. Seventy-nine percent of burst transfers were in the forward direction. We also observed rapid propagation of activity from sites of local electrical stimulation, and significant effects of inhibitory synapse blockade on bursting activity. Significance. These results suggest that this simple, substrate-controlled neuronal circuit can be applied to develop in vitro models of the function of cortical microcircuits or deep neural networks, better to elucidate the laws governing the dynamics of neuronal networks.

  4. The evolution of Sf. Gheorghe (Danube asymmetric deltaic lobe

    Directory of Open Access Journals (Sweden)

    Alfred VESPREMEANU-STROE

    2014-11-01

    Full Text Available The wave asymmetric Sf. Gheorghe lobe is the only active in the Danube delta where river mouth bar (and the associated barrier islands and spits continuously deployed a cyclic development for almost two millennia. During first stage, the Sf. Gheorghe distributary had a small discharge (with an order of magnitude lower than present which after that experienced a rapid increase in consequence of the successive avulsions of Împuţita (southern distributary of Sulina arm and Dunavăţ distributaries. Our morphological analyses together with the newly obtained chronology, revealed the multiple ridgesets structure of Sf. Gheorghe deltaic lobe. In fact, all ridgesets (10 follow a common morphodynamic pattern characterized by the cyclic succession of three stages: i subaqueous mouth bar development, ii barrier island emergence, iii barrier spit phase with several secondary spits derived from an updrift trunk ridge. The size of each ridgeset increased exponentially with every new cycle due to the constant lengthening of the coastline as the downdrift side of the lobe advances seaward through a series of progressively larger similar quadrilaterals, yielding to a constant enlargment of the delta front size. 

  5. Design and fabrication of asymmetric nanopores using pulsed PECVD

    Science.gov (United States)

    Kelkar, Sanket S.

    Manipulating matter at nanometric length scales is important for many electronic, chemical and biological applications. Structures such as nanopores demonstrate a phenomenon known as hindered transport which can be exploited in analytical applications such as DNA sequencing, ionic transistors, and molecular sieving. Precisely controlling the size, geometry and surface characteristics of the nanopores is important for realizing these applications. In this work, we employ relatively large template structures (˜ 100 nm) produced by track-etching or electron beam lithography. The pore size is then reduced to the desired level by deposition of material using pulsed plasma enhanced chemical vapor deposition (PECVD). Pulsed PECVD has been developed as a high throughput alternative to atomic layer deposition (ALD) to deliver self-limiting growth of thin films. The goal of this thesis is to extend the application of pulsed PECVD to fabricate asymmetric nanopores. In contrast to ALD, pulsed PECVD does not result in perfectly conformal deposition profiles, and predicting the final nanostructure is more complicated. A two dimensional feature scale model was developed to predict film profile evolution. The model was built in COMSOL, and is based on a diffusion reaction framework with a spatially varying Knudsen diffusion coefficient to account for the molecular transport inside the features. A scaling analysis was used to account for ALD exposure limitations that commonly occur when coating these extremely high aspect ratio features. The model was verified by cross-section microscopy of deposition profiles on patterned cylinders and trenches. The model shows that it is possible to obtain unique nanopore morphologies in pulsed PECVD that are distinct from either steady state deposition processes such as physical vapor deposition (PVD) or conventional ALD. Polymeric track etched (TE) membrane supports with a nominal size of 100 nm were employed as model template structures to

  6. Flexible Asymmetric Encapsulation for Dehydration-Responsive Hybrid Microfibers.

    Science.gov (United States)

    Chaurasia, Ankur S; Sajjadi, Shahriar

    2016-08-01

    A new class of smart alginate microfibers with asymmetric oil encapsulates is introduced. These fibers are produced by injecting an aqueous alginate solution into an outer aqueous calcium chloride solution to form alginate fibers, which are asymmetrically loaded with oil entities through eccentrically aligned inner capillaries. The fiber morphology and its degree of asymmetry can be tuned via altering the size, location, and frequency of the oil encapsulates. These asymmetric fibers reveal significant potential for applications where conventional symmetric fibers fail to perform. It is shown how asymmetric oil-encapsulated fibers can become dehydration-sensitive, and trigger the release of encapsulates if their hydration level drops below a critical value. It is also shown how the triggered response could be switched off on demand by stabilizing the oil encapsulates. The capability of asymmetric fibers to carry and release multiple cargos in parallel is demonstrated. The fibers loaded with equal-sized spheres are more asymmetric than those containing unequal drops, have a higher tensile strength, and show better potential for a triggered response. PMID:27352241

  7. Asymmetric central bank preferences and inflation rate in Tunisia

    Directory of Open Access Journals (Sweden)

    Imen KOBBI

    2013-04-01

    Full Text Available This article fits into the new strand of literature related to the asymmetric central bank preferences and its effect on the inflation dynamic. In reality, the central banker preferences are more likely to be asymmetric. Central banker can be, for various reasons, more averse toward deviations from target with one sign more than deviations from target with the other sign. The interaction of asymmetric central bank preferences with uncertainty arising from the volatility of inflation and output may affect the inflation movements. This paper aims to check the hypothesis that asymmetric central bank preferences are able to explain inflation rate for the case of Tunisia and to understand Central Bank of Tunisia preferences toward inflation rate and output during the period ranging from 1993 to 2010. We refer to a standard monetary model that includes asymmetric loss function and a linear supply curve which acts as a constraint on the central bank behavior. The results show that the inflation rate depends on the output gap and on the conditional variance of inflation and provide evidence for asymmetric central bank preferences. The Central Bank of Tunisia seems to be more averse to high inflation which is consistent with its ultimate goal explicitly announced to preserve price stability.

  8. Asymmetric nucleosomes flank promoters in the budding yeast genome.

    Science.gov (United States)

    Ramachandran, Srinivas; Zentner, Gabriel E; Henikoff, Steven

    2015-03-01

    Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that 5% of budding yeast (Saccharomyces cerevisiae) nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling.

  9. 1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

    Science.gov (United States)

    Mielgo, Antonia

    2016-01-01

    Summary Asymmetric catalysis represents a very powerful tool for the synthesis of enantiopure compounds. In this context the main focus has been directed not only to the search for new efficient chiral catalysts, but also to the development of efficient pronucleophiles. This review highlights the utility and first examples of 1H-imidazol-4(5H)-ones and thiazol-4(5H)-ones as pronucleophiles in catalytic asymmetric reactions. PMID:27340482

  10. Stability Improvement of High-Pressure-Ratio Turbocharger Centrifugal Compressor by Asymmetrical Flow Control—Part II: Nonaxisymmetrical Self-Recirculation Casing Treatment

    OpenAIRE

    Zheng, Xinqian; Zhang, Yangjun; Yang, Mingyang; Bamba, Takahiro; Tamaki, Hideaki

    2012-01-01

    This is part II of a two-part paper involving the development of an asymmetrical flow control method to widen the operating range of a turbocharger centrifugal compressor with high-pressure ratio. A nonaxisymmetrical self-recirculation casing treatment (SRCT) as an instance of asymmetrical flow control method is presented. Experimental and numerical methods were used to investigate the impact of nonaxisymmetrical SRCT on the surge point of the centrifugal compressor. First, the influence of t...

  11. Asymmetric transfer of auditory perceptual learning

    Directory of Open Access Journals (Sweden)

    Sygal eAmitay

    2012-11-01

    Full Text Available Perceptual skills can improve dramatically even with minimal practice. A major and practical benefit of learning, however, is in transferring the improvement on the trained task to untrained tasks or stimuli, yet the mechanisms underlying this process are still poorly understood. Reduction of internal noise has been proposed as a mechanism of perceptual learning, and while we have evidence that frequency discrimination (FD learning is due to a reduction of internal noise, the source of that noise was not determined. In this study, we examined whether reducing the noise associated with neural phase locking to tones can explain the observed improvement in behavioural thresholds. We compared FD training between two tone durations (15 and 100 ms that straddled the temporal integration window of auditory nerve fibers upon which computational modeling of phase locking noise was based. Training on short tones resulted in improved FD on probe tests of both the long and short tones. Training on long tones resulted in improvement only on the long tones. Simulations of FD learning, based on the computational model and on signal detection theory, were compared with the behavioral FD data. We found that improved fidelity of phase locking accurately predicted transfer of learning from short to long tones, but also predicted transfer from long to short tones. The observed lack of transfer from long to short tones suggests the involvement of a second mechanism. Training may have increased the temporal integration window which could not transfer because integration time for the short tone is limited by its duration. Current learning models assume complex relationships between neural populations that represent the trained stimuli. In contrast, we propose that training-induced enhancement of the signal-to-noise ratio offers a parsimonious explanation of learning and transfer that easily accounts for asymmetric transfer of learning.

  12. Asymmetric Dimethyl Arginine in Hypothyroid Patients

    International Nuclear Information System (INIS)

    Thyroid diseases may lead to endothelial dysfunction, however, the mechanism underlying the endothelial dysfunction in thyroid disease is still not clear. Asymmetric dimethyl arginine (ADMA), a novel inhibitor of endothelial nitric oxide synthetase (eNOS), was reported to inhibit nitric oxide (NO) synthesis from L-arginine. The present study was carried out to investigate ADMA levels together with effects of dislipidemia in sub-clinical and overt hypothyroid females. There were significant increase in the levels of total cholesterol, low density lipoprotein-cholesterol (LDL-c), high density lipoprotein-cholesterol (HDL-c), thyroid stimulating hormone (TSH) and ADMA in hypothyroid females as compared to controls while the levels of NO and free T4 were significantly decreased than controls. Sub-clinical hypothyroid females had significant high TSH, LDL-c and non-significantly high ADMA levels and total cholesterol as compared to controls while they had significant decrease in NO, HDL-c and non-significant decrease in free T4 as compared to controls. There were significant negative correlations between NO and both ADMA (r2 = 0.84) and free T4 (r2 = 0.95) in overt hypothyroid group while significant positive correlation (r2 = 0.85) was detected between TSH and HDL-c in the same group. These results are highly suggestive that the decrease of nitric oxide secondary to accumulation of ADMA represent an important pathogenic factor together with dyslipidemia in endothelial dysfunction and increased cardiovascular risk especially in hypothyroid females

  13. Hemispherical anomaly from asymmetric initial states

    Science.gov (United States)

    Ashoorioon, Amjad; Koivisto, Tomi

    2016-08-01

    We investigate if the hemispherical asymmetry in the CMB is produced from "asymmetric" excited initial conditions. We show that in the limit where the deviations from the Bunch-Davies vacuum are large and the scale of new physics is maximally separated from the inflationary Hubble parameter, the primordial power spectrum is modulated only by position-dependent dipole and quadrupole terms. Requiring the dipole contribution in the power spectrum to account for the observed power asymmetry, A =0.07 ±0.022 , we show that the amount of quadrupole terms is roughly equal to A2. The mean local bispectrum, which gets enhanced for the excited initial state, is within the 1 σ bound of Planck 2015 results for a large field model, fNL≃4.17 , but is reachable by future CMB experiments. The amplitude of the local non-Gaussianity modulates around this mean value, depending on the angle that the correlated patches on the 2d CMB surface make with the preferred direction. The amount of variation is minimized for the configuration in which the short and long wavelength modes are around the preferred pole and |k→3|≈|k→l ≈10|≪|k→1|≈|k→2|≈|k→l ≈2500| with fNLmin≈3.64 . The maximum occurs when these modes are at the antipode of the preferred pole, fNLmax≈4.81 . The difference of non-Gaussianity between these two configurations is as large as ≃1.17 , which can be used to distinguish this scenario from other scenarios that try to explain the observed hemispherical asymmetry.

  14. Asymmetric inhibitory treatment effects in multilingual aphasia.

    Science.gov (United States)

    Goral, Mira; Naghibolhosseini, Maryam; Conner, Peggy S

    2013-01-01

    Findings from recent psycholinguistic studies of bilingual processing support the hypothesis that both languages of a bilingual are always active and that bilinguals continually engage in processes of language selection. This view aligns with the convergence hypothesis of bilingual language representation. Furthermore, it is hypothesized that when bilinguals perform a task in one language they need to inhibit their other, nontarget language(s) and that stronger inhibition is required when the task is performed in the weaker language than in the stronger one. The study of multilingual individuals who acquire aphasia resulting from a focal brain lesion offers a unique opportunity to test the convergence hypothesis and the inhibition asymmetry. We report on a trilingual person with chronic nonfluent aphasia who at the time of testing demonstrated greater impairment in her first acquired language (Persian) than in her third, later learned language (English). She received treatment in English followed by treatment in Persian. An examination of her connected language production revealed improvement in her grammatical skills in each language following intervention in that language, but decreased grammatical accuracy in English following treatment in Persian. The increased error rate was evident in structures that are used differently in the two languages (e.g., auxiliary verbs). The results support the prediction that greater inhibition is applied to the stronger language than to the weaker language, regardless of their age of acquisition. We interpret the findings as consistent with convergence theories that posit overlapping neuronal representation and simultaneous activation of multiple languages and with proficiency-dependent asymmetric inhibition in multilinguals.

  15. Affective privilege: Asymmetric interference by emotional distracters

    Directory of Open Access Journals (Sweden)

    Crystal eReeck

    2011-09-01

    Full Text Available Numerous theories posit that affectively salient stimuli are privileged in their capacity to capture attention and disrupt ongoing cognition. Two underlying assumptions in this theoretical position are that the potency of affective stimuli transcends task boundaries (i.e., emotional distracters do not have to belong to a current task-set to disrupt processing and that there is an asymmetry between emotional and cognitive processing (i.e., emotional distracters disrupt cognitive processing, but not vice versa. These assumptions have remained largely untested, as common experimental probes of emotion-cognition interaction rarely manipulate task-relevance and only examine one side of the presumed asymmetry of interference. To test these propositions directly, a face-word Stroop protocol was adapted to independently manipulate (a the congruency between target and distracter stimulus features, (b the affective salience of distracter features, and (c the task-relevance of emotional compared to non-emotional target features. A three-way interaction revealed interdependent effects of distracter relevance, congruence, and affective salience. Compared to task-irrelevant distracters, task-relevant congruent distracters facilitated performance and task-relevant incongruent distracters impaired performance, but the latter effect depended on the nature of the target feature and task. Specifically, task-irrelevant emotional distracters resulted in equivalent performance costs as task-relevant non-emotional distracters, whereas task-irrelevant non-emotional distracters did not produce performance costs comparable to those generated by task-relevant emotional distracters. These results document asymmetric cross-task interference effects for affectively salient stimuli, supporting the notion of affective prioritization in human information processing.

  16. Highly Enantioselective Formation of α-Allyl-α-Arylcyclopentanones via Pd-Catalysed Decarboxylative Asymmetric Allylic Alkylation.

    Science.gov (United States)

    Akula, Ramulu; Doran, Robert; Guiry, Patrick J

    2016-07-11

    A highly enantioselective Pd-catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α-aryl-β-keto esters employing the (R,R)-ANDEN-phenyl Trost ligand has been developed. The product (S)-α-allyl-α-arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee). This represents one of the most highly enantioselective formations of an all-carbon quaternary stereogenic center reported to date. This reaction was demonstrated on a 4.0 mmol scale without any deterioration of enantioselectivity and was exploited as the key enantioselective transformation in an asymmetric formal synthesis of the natural product (+)-tanikolide. PMID:27191198

  17. On the influence that the ground electrode diameter has in the propulsion efficiency of an asymmetric capacitor in nitrogen gas

    CERN Document Server

    Martins, Alexandre A

    2011-01-01

    In this work the propulsion force developed in an asymmetric capacitor will be calculated for three different diameters of the ground electrode. The used ion source is a small diameter wire, which generates a positive corona discharge in nitrogen gas directed to the ground electrode. By applying the fluid dynamic and electrostatic theories all hydrodynamic and electrostatic forces that act on the considered geometries will be computed in an attempt to provide a physical insight on the force mechanism that acts on the asymmetrical capacitors, and also to understand how to increase the efficiency of propulsion.

  18. Tunable hard X-ray spectrometer utilizing asymmetric planes of a quartz transmission crystal.

    Science.gov (United States)

    Seely, John F; Henins, Albert; Feldman, Uri

    2016-05-01

    A Cauchois type hard x-ray spectrometer was developed that utilizes the (301) diffraction planes at an asymmetric angle of 23.51° to the normal to the surface of a cylindrically curved quartz transmission crystal. The energy coverage is tunable by rotating the crystal and the detector arm, and spectra were recorded in the 8 keV to 20 keV range with greater than 2000 resolving power. The high resolution results from low aberrations enabled by the nearly perpendicular angle of the diffracted rays with the back surface of the crystal. By using other asymmetric planes of the same crystal and rotating to selected angles, the spectrometer can operate with high resolution up to 50 keV.

  19. Stability characteristics of the open channel flow above the asymmetrical irregular sand ripples

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Sandy bed cannot keep its original smoothness as the flows pass. With the increase of the flow intensity, the bed forms will appear as sand ripples and dune in turn. Among these morphologies, the sand ripple scale is the smallest, which is generally symmetrical when it just appears, but as time goes on, the asymmetrical form gradually develops. Just because of this sand ripples asymmetry, it manifests the influence of the flow on the bed morphology and also the impact on the laminar flow dynamical process, especially the stability characteristics. The stability features of laminar flow on open channels with the asymmetrical sand ripples are discussed, and also the results on the symmetrical sand ripples are compared in detail.

  20. A carbon nanotube confinement strategy to implement homogeneous asymmetric catalysis in the solid phase.

    Science.gov (United States)

    Hashimoto, Kazuki; Kumagai, Naoya; Shibasaki, Masakatsu

    2015-03-01

    A readily recyclable asymmetric catalyst has been developed based on the self-assembly of a homogeneous catalyst in a fibrous network of multiwalled carbon nanotubes (MWNTs). Dimerization of an amide-based chiral ligand with a suitable spacer allows for the efficient formation of a heterogeneous catalyst by self-assembly on addition of Er(OiPr)3. The self-assembly proceeds in the MWNT fibrous network and small clusters of assembled catalyst are confined in the MWNTs, producing an easily handled solid-phase catalyst. The resulting MWNT-confined catalyst exhibits a good catalytic performance in a catalytic asymmetric Mannich-type reaction, which can be conducted in a repeated batch system and in a continuous-flow platform.

  1. Direct asymmetric vinylogous Michael addition of cyclic enones to nitroalkenes via dienamine catalysis

    Science.gov (United States)

    Bencivenni, Giorgio; Galzerano, Patrizia; Mazzanti, Andrea; Bartoli, Giuseppe; Melchiorre, Paolo

    2010-01-01

    In spite of the many catalytic methodologies available for the asymmetric functionalization of carbonyl compounds at their α and β positions, little progress has been achieved in the enantioselective carbon–carbon bond formation γ to a carbonyl group. Here, we show that primary amine catalysis provides an efficient way to address this synthetic issue, promoting vinylogous nucleophilicity upon selective activation of unmodified cyclic α,β-unsaturated ketones. Specifically, we document the development of the unprecedented direct and vinylogous Michael addition of β-substituted cyclohexenone derivatives to nitroalkenes proceeding under dienamine catalysis. Besides enforcing high levels of diastereo- and enantioselectivity, chiral primary amine catalysts derived from natural cinchona alkaloids ensure complete γ-site selectivity: The resulting, highly functionalized vinylogous Michael adducts, having two stereocenters at the γ and δ positions, are synthesized with very high fidelity. Finally, we describe the extension of the dienamine catalysis-induced vinylogous nucleophilicity to the asymmetric γ-amination of cyclohexene carbaldehyde. PMID:20566884

  2. Construction of an Asymmetric Quaternary Carbon Center via Allylation of Hydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Bum; Satyender, Apuri; Jang, Doo Ok [Yonsei Univ., Wonju (Korea, Republic of)

    2013-11-15

    Asymmetric indium-mediated allylation of imine derivatives bearing a chiral auxiliary is a reliable strategy for the synthesis of chiral homoallylic amines. Various techniques for indium-mediated stereoselective allylation of imines bearing a chiral auxiliary have been reported. In 1997 Loh and co-workers reported indium-mediated allylation with imines derived from L-valine methyl ester. Since then, many forms of indium-mediated allylation bearing a chiral auxiliary have been reported, including imines derived from (S)-valinol, (R)-phenylglycinol, uracil, (R)-phenylglycinol methyl ester, N-tert-butanesufinamide, and (1R,2S)-1-amino-2-indanol. However, the synthesis of chiral auxiliaries often involves a laborious multi-step synthesis with expensive reagents. Therefore, the development of readily accessible chiral auxiliaries for asymmetric indium-mediated all-ylation is in high demand.

  3. GENERALIZED ASYMMETRIC HYSTERESIS MODEL OF CONTROLLABLE MAGNETORHEOLOGICAL DAMPER FOR VEHICLE SUSPENSION ATTENUATION

    Institute of Scientific and Technical Information of China (English)

    Wang Enrong; Ma Xiaoqing; Su Chunyi; Rakheja Subhash

    2004-01-01

    A generalized model is synthesized to characterize the asymmetric hysteresis force-velocity (F-v) properties of the magneto-rheological (MR) fluids damper.The model is represented as a function of the command current,excitation frequency,and displacement amplitude,based on the symmetric and asymmetric sigmoid functions.The symmetric hysteresis damping properties of the controllable MR-damper and properties of the conventional passive hydraulic damper can also be described by the proposed model.The validity of the model is verified by experiments,which show that the results calculated from the model are consistent with the measured data.In addition,it is shown that the model applies to a wide vibration frequency range.The proposed model has potential application in vehicle suspension design employing the symmetry MR-damper,and also in developing the asymmetry MR-damper especially for the vehicle suspension attenuation.

  4. Application of spherical Ni(OH)2/CNTs composite electrode in asymmetric supercapacitor

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-feng; RUAN Dian-bo; YOU Zheng

    2006-01-01

    The composite electrodes consisting of carbon nanotubes and spherical Ni(OH)2 are developed by mixing nickel hydroxide, carbon nanotubes and carbonyl nickel powder together in 8-1-1 ratio. A maximum capacitance of 311 F/g is obtained for an electrode prepared with the precipitation process. In order to enhance energy density, an asymmetric type pseudo-capacitor/electric double layer capacitor is considered and its electrochemical properties are investigated. Values for the specific energy and maximum specific power of 25.8 W-h/kg and 2.8 kW/kg, respectively, are demonstrated for a cell voltage between 0 and 1.6 V. By using the modified cathode of a Ni(OH)2/carbon nanotube composite electrode, the asymmetric supercapacitor exhibits high energy density and stable power characteristics.

  5. Three-Dimensional Quantitative Optical Measurement of Asymmetrically Focused Ultrasound Pressure Field

    Science.gov (United States)

    Shimazaki, Yuta; Harigane, Soichiro; Yoshizawa, Shin; Umemura, Shin-ichiro

    2012-07-01

    High-intensity focused ultrasound (HIFU) is used for the treatment of tumors such as prostate cancer. In the development of this technique, an accurate and fast measurement of the HIFU pressure field is important. A hydrophone is generally used for the measurement, but it might disturb the pressure field and scanning it in the field takes a long time. On the other hand, optical ultrasonic field mapping has the advantages of speed and its nature of not by interfering with the acoustic field. In this study, we reconstructed an asymmetric ultrasound field by optical measurement using a computed tomography (CT) algorithm. The asymmetric field was generated by a focused transducer with four elements. Also, the absolute measurement of ultrasonic pressure was checked by measuring the center of the field of the charge-coupled device (CCD) camera. The results showed overall agreement with those of hydrophone measurement.

  6. Asymmetric ion transport through ion-channel-mimetic solid-state nanopores.

    Science.gov (United States)

    Guo, Wei; Tian, Ye; Jiang, Lei

    2013-12-17

    different environmental conditions in the electrolyte solutions on either side of the nanochannel. The novel and well-controlled nanofluidic phenomena have become the foundation for many promising applications, and we have highlighted several representative examples. Inspired by the electrogenic cell of the electric eel, we have demonstrated a proof-of-concept nanofluidic reverse electrodialysis system (NREDS) that converts salinity gradient energy into electricity by means of net diffusion current. We have also constructed chirality analysis systems into nanofluidic architectures and monitored these sensing events as the change in the degree of ionic current rectification. Moreover, we have developed a biohybrid nanosystem, in which we reconstituted the F0F1-ATPase on a liposome-coated, solid-state nanoporous membrane. By applying a transmembrane proton concentration gradient, the biohybrid nanodevice can synthesize ATP in vitro. These findings have improved our understanding of the asymmetric ion transport phenomena in synthetic nanofluidic systems and offer innovative insights into the design of functional nanofluidic devices.

  7. An Asymmetric Synthetic Approach to the A-ring of the Taxol Family of Anti-Cancer Compounds

    Directory of Open Access Journals (Sweden)

    M. L. Marin

    1998-02-01

    Full Text Available A synthetic route developed for the preparation of the A-ring of Taxol family of molecules is reported. By means of an intramolecular Diels-Alder reaction an asymmetric approach to this ring has been accomplished. Also, initial studies to prepare the A ring using an intramolecular Diels-Alder reaction have been successful.

  8. Ru/Me-BIPAM-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes and α-Ketoesters

    Directory of Open Access Journals (Sweden)

    Momoko Watanabe

    2011-06-01

    Full Text Available A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(arylmethanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM achieved excellent enantioselectivities.

  9. Exploring the decomposition pathways of iron asymmetric transfer hydrogenation catalysts.

    Science.gov (United States)

    Lagaditis, Paraskevi O; Sues, Peter E; Lough, Alan J; Morris, Robert H

    2015-07-21

    Our group has developed a series of iron-based asymmetric transfer hydrogenation (ATH) catalysts for the reduction of polar double bonds. The activation of the precatalysts as well as the catalytic mechanism have been thoroughly investigated, but the decomposition pathways of these systems are poorly understood. Herein, we report a study of the deactivation pathways for an iron ATH catalyst under catalytically relevant conditions. The decomposition pathways were examined using experimental techniques and density functional theory (DFT) calculations. The major decomposition products that formed, Fe(CO)((Et)2PCH2CH2CHCHNCH2CH2P(Et)2) (3a) and Fe(CO)((Et)2PCH2CH2C(Ph)C(Ph)NCH2CH2P(Et)2) (3b), had two amido donors as well as a C=C bond on the diamine backbone of the tetradentate ligand. These species were identified by NMR studies and one was isolated as a bimetallic complex with Ru(II)Cp*. Two minor iron hydride species also formed concurrently with 3a, as determined by NMR studies, one of which was isolated and contained a fully saturated ligand as well as a hydride ligand. None of the compounds that were isolated were found to be active ATH catalysts. PMID:25373607

  10. Transport of pulmonary secretions by asymmetric high frequency oscillation

    International Nuclear Information System (INIS)

    Asymmetric high frequency oscillation (AHFO) was investigated as a mechanism for augmenting the clearance of excess pulmonary secretions from the airways of the lungs. In vitro and in vivo models were developed to test its ability to predictably transport pulmonary secretions. The augmentation of mucus transport by 10 Hz AHFO was investigated in the canine trachea. Ventilation of eight dogs (2 studies each) was performed with three AHFO power settings in random order and conventional mechanical ventilation (CMV) before or after the AHFO trials. Prior to each trial, 35-45 μl of canine muscus mixed with a radiotagged colloid (99Tc/sup m/) was instilled in the distal trachea. As the radiotagged mixture traveled up the trachea, tracheal muscus velocities (TMV) were recorded on six channels with a multidetector probe. CMV mean TMVs before and after AHFO were not significantly different. The mean TMV of 6.3 +/- 2.6 mm/min at 30% power AHFO was faster than the CMV mean TVM of 4.1 +/- 2.1 mm/min (p <0.05)

  11. Dcc regulates asymmetric outgrowth of forebrain neurons in zebrafish.

    Directory of Open Access Journals (Sweden)

    Jingxia Gao

    Full Text Available The guidance receptor DCC (deleted in colorectal cancer ortholog UNC-40 regulates neuronal asymmetry development in Caenorhabditis elegans, but it is not known whether DCC plays a role in the specification of neuronal polarity in vertebrates. To examine the roles of DCC in neuronal asymmetry regulation in vertebrates, we studied zebrafish anterior dorsal telencephalon (ADt neuronal axons. We generated transgenic zebrafish animals expressing the photo-convertible fluorescent protein Kaede in ADt neurons and then photo-converted Kaede to label specifically the ADt neuron axons. We found that ADt axons normally project ventrally. Knock down of Dcc function by injecting antisense morpholino oligonucleotides caused the ADt neurons to project axons dorsally. To examine the axon projection pattern of individual ADt neurons, we labeled single ADt neurons using a forebrain-specific promoter to drive fluorescent protein expression. We found that individual ADt neurons projected axons dorsally or formed multiple processes after morpholino knock down of Dcc function. We further found that knock down of the Dcc ligand, Netrin1, also caused ADt neurons to project axons dorsally. Knockdown of Neogenin1, a guidance receptor closely related to Dcc, enhanced the formation of aberrant dorsal axons in embryos injected with Dcc morpholino. These experiments provide the first evidence that Dcc regulates polarized axon initiation and asymmetric outgrowth of forebrain neurons in vertebrates.

  12. Asymmetric Transfer Hydrogenation of ω -Bromo Acetophenones in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    Wang Fei; Liu Hui; Cui Xin; Cun Linfeng; Zhu Jin; Deng Jingen; Jiang Yaozhong

    2004-01-01

    Optical active ω-bromophenylethanols are useful building blocks for synthesis of various pharmaceuticals such as α 1-, β 2-, and β 3- adrenergic receptor agonists, which are always obtained though a biotransformative pathway and using boron reagent with rigorous conditions [1]. To our knowledge, the metal-catalysed transfer hydrogenation is seldom applied in this reaction. Recently we have developed a water-soluble chiral Ru-complex and applied successfully in transfer hydrogenation of ω-bromo acetophenones in aqueous media [2], which can not be performed in homogeneous system with HCOOH/NEt3 as hydrogen donor[3] .In this paper, we will report that asymmetric transfer hydrogenation of ω-bromo acetophenones was successfully performed in aqueous media by employing hydrophobic Rh-amido complex (TsDPEN-Rh) as catalyst and HCOONa as hydrogen donor. Moreover, marked increasing of activity and high enantioselectivity (up to 98%) of ω-bromo acetophenone 1a was found in the presence of different micelles or vesicles. This method was also applied successfully in preparation of the important chiral medicinal intermediates, such as the precursor of salbutamol, 2b and fermoterol, 2c with high enantioselectivity.

  13. Time-symmetrized description of nonunitary time asymmetric quantum evolution

    International Nuclear Information System (INIS)

    We discuss how systems which evolve manifestly asymmetrically in time can be described within the framework of the time-symmetrized quantum mechanics. An obvious case of asymmetry arises when a pure state evolves into a mixed state via effectively non-unitary evolution. A two-state method for finding the intermediate probability in postselected systems under such evolution is developed and the time-symmetry aspects of the method are explicitly considered. A specific feature is the existence of the so-called second scenario in which the state originating from the postselection measurement evolves under different evolution superoperator than the state from the preselection measurement. The evolution of the second scenario is explicitly defined. We illustrate the method with two characteristic examples: the spontaneous deexcitation of atoms and the systems approaching thermal equilibrium. We consider the systems with two energy levels and calculate the time-symmetrized probability of finding the system in excited state, under general preselection and postselection conditions. The consequences of the asymmetry of the time evolution on this probability are discussed. It is demonstrated that the arrow of time can be reconstructed in some special cases of postselected systems, while, for a general system, this is not the case. (paper)

  14. The asymmetric impact of natural disasters on China's bilateral trade

    Science.gov (United States)

    Meng, Y.; Yang, S.; Shi, P.; Jeager, C. C.

    2015-10-01

    Globalization and technological revolutions are making the world more interconnected. International trade is an important approach linking the world. Since the 2011 Tohoku earthquake and tsunami in Japan shocked the global supply chain, more attention has been paid to the global impact of large-scale disasters. China is the second largest trader in the world and faces frequent natural disasters. Therefore, this study proposes a gravity model for China's bilateral trade tailored to national circumstances and estimates the impact of natural disasters in China and trading partner countries on Chinese imports and exports. We analyzed Chinese and trading partner statistical data from 1980 to 2012. Study results show the following: (1) China's natural disasters have a positive impact on exports but have no significant impact on imports; (2) trading partner countries' natural disasters reduce Chinese imports and exports; (3) both development level and land area of the partners are important in determining the intensity of natural disaster impacts on China's bilateral trade. The above findings suggest that the impact of natural disasters on trade is asymmetric and significantly affected by other factors, which demand further study.

  15. Non Heme System Asymmetric Epoxidation Reaction Made Progress

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Funded by the National Natural Science Foundation of China and the Chinese Academy of Sciences "Hundred Talents Program", the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences Oxo Synthesis and Selective Oxidation State Key Laboratory of biological and Biomimetic Catalytic task group has recently developed a new type of non heme enzyme simulation system, the system uses the benz- imidazole instead of four nitrogen ligands pyridine units, natural proline derivatives two amine instead of HMDA skeleton, the manganese complexes in asymmetric epoxidation reaction shown high activity, but in 1/10000 the amount of catalyst under conditions of high selectivity to obtain corresponding product, TON (Turnover numbers) up to 9600, TOF (Turnover frequency) up to 59000 h-1. It is currently reported the highest activity in epoxidation catalyst. Use the H202/AcOH or peracetic acid as oxidant, 180 isotope la- beling experiments, were found different degrees of 180 isotope labeling of epoxy products, won the first direct evidence of response is obtained by the high Mn O intermediates in the process, the work was pub- lished recently in Chem. Eur. J. (Chem. Eur. J. 2012, 18, 6750--6753. ).

  16. Optical asymmetric watermarking using modified wavelet fusion and diffractive imaging

    Science.gov (United States)

    Mehra, Isha; Nishchal, Naveen K.

    2015-05-01

    In most of the existing image encryption algorithms the generated keys are in the form of a noise like distribution with a uniform distributed histogram. However, the noise like distribution is an apparent sign indicating the presence of the keys. If the keys are to be transferred through some communication channels, then this may lead to a security problem. This is because; the noise like features may easily catch people's attention and bring more attacks. To address this problem it is required to transfer the keys to some other meaningful images to disguise the attackers. The watermarking schemes are complementary to image encryption schemes. In most of the iterative encryption schemes, support constraints play an important role of the keys in order to decrypt the meaningful data. In this article, we have transferred the support constraints which are generated by axial translation of CCD camera using amplitude-, and phase- truncation approach, into different meaningful images. This has been done by developing modified fusion technique in wavelet transform domain. The second issue is, in case, the meaningful images are caught by the attacker then how to solve the copyright protection. To resolve this issue, watermark detection plays a crucial role. For this purpose, it is necessary to recover the original image using the retrieved watermarks/support constraints. To address this issue, four asymmetric keys have been generated corresponding to each watermarked image to retrieve the watermarks. For decryption, an iterative phase retrieval algorithm is applied to extract the plain-texts from corresponding retrieved watermarks.

  17. Asymmetrical sabotage tactics, nuclear facilities/materials, and vulnerability analysis

    International Nuclear Information System (INIS)

    Full text: The emerging paradigm of a global community wherein post-modern political violence is a fact of life that must be dealt with by safety and security planners is discussed. This paradigm shift in the philosophy of terrorism is documented by analysis of the emerging pattern of asymmetrical tactics being employed by terrorists. Such philosophical developments in violent political movements suggest a shift in the risks that security and safety personnel must account for in their planning for physical protection of fixed site nuclear source facilities like power generation stations and the eventual storage and transportation of the by-products of these facilities like spent nuclear fuel and other high level wastes. This paper presents a framework for identifying these new political realities and related threat profiles, suggests ways in which security planners and administrators can design physical protection practices to meet these emerging threats, and argues for global adoption of standards for the protection of nuclear facilities that could be used as a source site from which terrorists could inflict a mass contamination event and for standards related to the protection of the waste materials that can be used in the production of radiological weapons of mass victimization. (author)

  18. Analysis of Dual-beam Asymmetrical Torsional Bi-Material Cantilever for Temperature Sensing Applications

    CERN Document Server

    Conwell, Matthew; McKinley, Ian; Shi, Xiaoyang

    2012-01-01

    An extremely sensitive temperature measurement MEMS device is developed based on the principle of structural deflection in a bi-material cantilever caused by a difference in thermal expansion coefficients. A dual-beam asymmetrical geometry is used to produce a torsional response from the device. An analytical model is developed to predict the performance and optimize the free parameters of the device. In this work, it is performed to analyze the flexural and torsional eigenfrequencies as well as confirm the theoretical predictions of DC and AC response. Lastly, a procedure is developed to allow fabrication of the device using equipment available in the Columbia University clean room.

  19. A physical model of asymmetric vortices flow structure in regular state over slender body at high angle of attack

    Institute of Scientific and Technical Information of China (English)

    邓学蓥; 王刚; 陈学锐; 王延奎; 刘沛清; 郗忠祥

    2003-01-01

    In subcritical Reyolds number flow region, the repeatable and determinate asymmetric vortices flow at regular state can be obtained by manually setting mini-perturbation on the nose of a pointed ogive-cylinder model at high angle of attack and zero side slip. Test results of this study involve surface pressure distributions, sectional-side-force distributions and flow visualizations. The analyses of these results revealed a complicated multi-vortices system at regular state in which asymmetric twin vortices with inception region and fully developed region, asymmetric triple vortices, four vortices region, five vortices region and Karman-vortex-street-like flow region are developed along the slender body. The correlation between multi-vortices system structures and corresponding sectional-side-force distribution is given. The behaviors of multi-vortices flow structure at the peculiar points of sectional-side-force distributions and characteristics of corresponding pressure distribution are analysed. Finally, a physical model of asymmetric multi-vortices flow structure in regular state over slender body is developed.

  20. Electrochemical study of aqueous asymmetric FeWO4/MnO2 supercapacitor

    Science.gov (United States)

    Goubard-Bretesché, Nicolas; Crosnier, Olivier; Buvat, Gaëtan; Favier, Frédéric; Brousse, Thierry

    2016-09-01

    The concept of an asymmetric FeWO4/MnO2 electrochemical capacitor cycled in a neutral aqueous electrolyte is presented for the first time. Commercially available cryptomelane-type MnO2 and synthesized nanocrystalline FeWO4 were used as positive and negative electrode materials, respectively. Prior to assembling the cell, the electrodes have been individually tested in a 5 M LiNO3 electrolyte solution to define both the adequate balance of active material in the supercapacitor and the proper working voltage window. Then, the full asymmetric device has been cycled between 0 and 1.4 V for over 40,000 cycles and subjected to accelerated ageing tests under floating conditions at different voltages, without any significant change on its electrochemical behavior. This remarkable stability shows the interest of developing full oxide-based asymmetric supercapacitors operating in non-toxic aqueous electrolytes that could compete with commercial carbon-based electrochemical double-layer capacitors.