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Sample records for asymmetric dimethylarginine adma

  1. High asymmetric dimethylarginine (ADMA) levels in patients with brucellosis.

    Science.gov (United States)

    Mengeloglu, Zafer; Sünnetcioglu, Mahmut; Tosun, Mehmet; Kücükbayrak, Abdülkadir; Ceylan, Mehmet Resat; Baran, Ali Irfan; Karahocagil, Mustafa; Akdeniz, Hayrettin

    2014-02-01

    Asymmetric dimethylarginine (ADMA) is the main endogenous inhibitor of nitric oxide synthase and is considered to be associated with endothelial dysfunction. Brucellosis, a zoonotic disease caused by Brucella spp., can manifest as vasculopathy. The present study was performed to investigate the relationship between ADMA and brucellosis. Serum samples from 39 patients with an accurate diagnosis of brucellosis and from 18 healthy control individuals were included in this study. ADMA levels were significantly higher in the patient group than the controls (P brucellosis and high levels of ADMA. In conclusion, ADMA levels should be tested in brucellosis cases and that further studies to clarify the mechanism underlying the association between ADMA and brucellosis are required.

  2. Asymmetric Dimethylarginine in Chronic Obstructive Pulmonary Disease (ADMA in COPD

    Directory of Open Access Journals (Sweden)

    Jeremy A. Scott

    2014-04-01

    Full Text Available l-Arginine metabolism including the nitric oxide (NO synthase and arginase pathways is important in the maintenance of airways function. We have previously reported that accumulation of asymmetric dimethylarginine (ADMA in airways, resulting in changes in l-arginine metabolism, contributes to airways obstruction in asthma and cystic fibrosis. Herein, we assessed l-arginine metabolism in airways of patients with chronic obstructive pulmonary disease (COPD. Lung function testing, measurement of fractional exhaled NO (FeNO and sputum NO metabolites, as well as quantification of l-arginine metabolites (l-arginine, l-ornithine, l-citrulline, ADMA and symmetric dimethylarginine using liquid chromatography-mass spectrometry (LC-MS were performed. Concentrations of l-ornithine, the product of arginase activity, correlated directly with l-arginine and ADMA sputum concentrations. FeNO correlated directly with pre- and post-bronchodilator forced expiratory volume in one second (FEV1. Sputum arginase activity correlated inversely with total NO metabolite (NOx and nitrite concentrations in sputum, and with pre- and post-bronchodilator FEV1. These findings suggest that ADMA in COPD airways results in a functionally relevant shift of l-arginine breakdown by the NO synthases towards the arginase pathway, which contributes to airway obstruction in these patients.

  3. MCD diet-induced steatohepatitis is associated with alterations in asymmetric dimethylarginine (ADMA) and its transporters.

    Science.gov (United States)

    Di Pasqua, Laura G; Berardo, Clarissa; Rizzo, Vittoria; Richelmi, Plinio; Croce, Anna Cleta; Vairetti, Mariapia; Ferrigno, Andrea

    2016-08-01

    Using an experimental model of NASH induced by a methionine-choline-deficient (MCD) diet, we investigated whether changes occur in serum and tissue levels of asymmetric dimethylarginine (ADMA). Male Wistar rats underwent NASH induced by 8-week feeding with an MCD diet. Serum and hepatic biopsies at 2, 4 and 8 weeks were taken, and serum enzymes, ADMA and nitrate/nitrite (NOx), were evaluated. Hepatic biopsies were used for mRNA and protein expression analysis of dimethylarginine dimethylaminohydrolase-1 (DDAH-1) and protein methyltransferases (PRMT-1), enzymes involved in ADMA metabolism and synthesis, respectively, and ADMA transporters (CAT-1, CAT-2A and CAT-2B). Lipid peroxides (TBARS), glutathione, ATP/ADP and DDAH activity were quantified. An increase in serum AST and ALT was detected in MCD animals. A time-dependent decrease in serum and tissue ADMA and increase in mRNA expression of DDAH-1 and PRMT-1 as well as higher rates of mRNA expression of CAT-1 and lower rates of CAT-2A and CAT-2B were found after 8-week MCD diet. An increase in serum NOx and no changes in protein expression in DDAH-1 and CAT-1 and higher content in CAT-2 and PRMT-1 were found at 8 weeks. Hepatic DDAH activity decreased with a concomitant increase in oxidative stress, as demonstrated by high TBARS levels and low glutathione content. In conclusion, a decrease in serum and tissue ADMA levels in the MCD rats was found associated with a reduction in DDAH activity due to the marked oxidative stress observed. Changes in ADMA levels and its transporters are innovative factors in the onset and progression of hepatic alterations correlated with MCD diet-induced NASH. PMID:27357826

  4. Asymmetric dimethylarginine (ADMA)--a modulator of nociception in opiate tolerance and addiction?

    Science.gov (United States)

    Kielstein, Anousheh; Tsikas, Dimitrios; Galloway, Gantt P; Mendelson, John E

    2007-09-01

    Nitric oxide (NO) is generated from l-arginine by NO synthases, of which three forms have been identified: endothelial, inducible and neuronal (eNOS, iNOS and nNOS, respectively). The l-arginine metabolite asymmetric dimethylarginine (ADMA) is a potent, noncompetitive inhibitor of nNOS, while its congener N(G)-monomethyl-l-arginine (l-NMMA) is a less potent, competitive inhibitor. In rat neurons large amounts of ADMA are found, suggesting its importance in modulating neuronal activity. Humans generate approximately 300mumol ( approximately 60mg) ADMA per day. It is released from myelin basic proteins that are highly expressed in neuronal tissue. ADMA is mainly degraded by the action of the enzyme dimethylarginine dimethylaminohydrolase (DDAH), which exists in two isoforms. DDAH1 is highly expressed in brain, suggesting specific function in this area. The presence of nNOS and DDAH1 in brain suggests that ADMA may have specific CNS activity and be more than an unregulated metabolite. Increased NO production-either prior to or concurrently with opioid administration-results in an enhanced rate and extent of development of tolerance to morphine in mice. NO produces an alteration in the mu-opioid receptor that increases constitutive receptor activity. It thereby reduces the ability of a selective mu-opioid agonist to activate the mu-opioid receptor; these in vitro molecular effects occur in a time course consistent with the in vivo development of antinociceptive tolerance in mice. Amongst many other synthetic NOS inhibitors of varying specificity, 7-nitroindazole (7-NI) has been shown to have a high affinity (IC(50) 0.71 microM) to nNOS. Selective blockade of nNOS by 7-NI attenuated morphine withdrawal in opiate dependent rats, suggesting nNOS as a viable target for development of pharmacotherapies. We hypothesize that, by inhibiting nNOS and reducing NO levels, ADMA may decrease mu-opiate receptor constitutive activity, resulting in alteration of the analgesic dose

  5. Dimethylarginine Dimethylaminohydrolase 2 (DDAH 2) Gene Polymorphism, Asymmetric Dimethylarginine (ADMA) Concentrations, and Risk of Coronary Artery Disease: A Case-Control Study

    Science.gov (United States)

    Xuan, Chao; Xu, Long-Qiang; Tian, Qing-Wu; Li, Hui; Wang, Qing; He, Guo-Wei; Lun, Li-Min

    2016-01-01

    Asymmetric dimethylarginine (ADMA) has been shown to be an independent predictor of cardiovascular diseases. Dimethylarginine dimethylaminohydrolase 2 (DDAH 2) promotes the metabolism of ADMA and plays a key role in the regulation of acute inflammatory response. With the present study, we investigated the relationship between DDAH 2 polymorphisms and risk of coronary artery disease (CAD) and its association to plasma ADMA concentrations. We used the haplotype-tagging SNP approach to identify tag SNPs in DDAH 2. The SNPs were genotyped by PCR and sequenced in 385 CAD patients and 353 healthy controls. Plasma concentrations of ADMA were determined using enzyme-linked immunosorbent assay (ELISA). A promoter polymorphism −449C/G (rs805305) in DDAH 2 was identified. Compared with the ADMA concentrations in CC genotype (0.328 ± 0.077 μmol/l), ADMA concentrations in CG + GG genotype were significantly increased (0.517 ± 0.090 μmol/l, P < 0.001). No significant associations between the −449C/G and risk of CAD were detected in the genetic models. The results of this study suggest that Genetic −499C/G polymorphism in DDAH 2 gene may affect the plasma ADMA concentrations in patients with CAD. However, it does not indicate a novel genetic risk marker for CAD. PMID:27677852

  6. Effect of Lowering Asymmetric Dimethylarginine (ADMA on Vascular Pathology in Atherosclerotic ApoE-Deficient Mice with Reduced Renal Mass

    Directory of Open Access Journals (Sweden)

    Johannes Jacobi

    2014-03-01

    Full Text Available The purpose of the work was to study the impact of the endogenous nitric oxide synthase (NOS inhibitor asymmetric dimethylarginine (ADMA and its degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH1, on atherosclerosis in subtotally nephrectomized (SNX ApoE-deficient mice. Male DDAH1 transgenic mice (TG, n = 39 and C57Bl/6J wild-type littermates (WT, n = 27 with or without the deletion of the ApoE gene underwent SNX at the age of eight weeks. Animals were sacrificed at 12 months of age, and blood chemistry, as well as the extent of atherosclerosis within the entire aorta were analyzed. Sham treated (no renal mass reduction ApoE-competent DDAH1 transgenic and wild-type littermates (n = 11 served as a control group. Overexpression of DDAH1 was associated with significantly lower ADMA levels in all treatment groups. Surprisingly, SNX mice did not exhibit higher ADMA levels compared to sham treated control mice. Furthermore, the degree of atherosclerosis in ApoE-deficient mice with SNX was similar in mice with or without overexpression of DDAH1. Overexpression of the ADMA degrading enzyme, DDAH1, did not ameliorate atherosclerosis in ApoE-deficient SNX mice. Furthermore, SNX in mice had no impact on ADMA levels, suggesting a minor role of this molecule in chronic kidney disease (CKD in this mouse model.

  7. Elevated concentration of asymmetric dimethylarginine (ADMA) in individuals with metabolic syndrome.

    Science.gov (United States)

    Palomo, Iván; Contreras, Alejandra; Alarcón, L Marcelo; Leiva, Elba; Guzmán, Luis; Mujica, Verónica; Icaza, Gloria; Díaz, Nora; González, Daniel R; Moore-Carrasco, Rodrigo

    2011-05-31

    The metabolic syndrome (MS) is a cluster of pathophysiological alterations that includes the presence of hypertension, insulin resistance, dyslipidemia, and abdominal obesity. MS is associated with increased risk of developing diabetes and cardiovascular diseases. Endothelial dysfunction with impaired nitric oxide (NO) bioavailability has been implicated in insulin resistance and hypertension. NO is synthesized by nitric oxide synthase (NOS) using l-arginine as substrate. Asymmetric dimethyl arginine (ADMA) is a major and potent endogenous NOS inhibitor, associated with cardiovascular and renal diseases. We tested the hypothesis that plasmatic ADMA levels are increased in patients with MS. We studied 85 adult individuals from Talca, Chile, separated in two groups, 48 individuals with MS (according to modified ATP III criteria), and 37 individuals without MS as controls. ADMA levels were significantly increased in the MS group (mean±standard deviation 0.71±0.38 vs. 0.48±0.28μmol/L, p=0.0009). Furthermore, the levels of ADMA were modestly but significantly correlated with waist circumference (p=0.01) but not with the other components of MS (blood pressure, glycemia, triglycerides and high density lipoprotein cholesterol HDL-c). These results suggest a possible link between increased ADMA levels and the MS. PMID:21419857

  8. Exogenous Asymmetric Dimethylarginine (ADMA) in Pathogenesis of Ischemia-Reperfusion-Induced Gastric Lesions: Interaction with Protective Nitric Oxide (NO) and Calcitonin Gene-Related Peptide (CGRP)

    OpenAIRE

    Marcin Magierowski; Katarzyna Jasnos; Zbigniew Sliwowski; Marcin Surmiak; Gracjana Krzysiek-Maczka; Agata Ptak-Belowska; Slawomir Kwiecien; Tomasz Brzozowski

    2014-01-01

    Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthesis inhibitor and pro-inflammatory factor. We investigated the role of ADMA in rat gastric mucosa compromised through 30 min of gastric ischemia (I) and 3 h of reperfusion (R). These I/R animals were pretreated with ADMA with or without the combination of l-arginine, calcitonin gene-related peptide (CGRP) or a small dose of capsaicin, all of which are known to afford protection against gastric lesions, or with a farn...

  9. Plasma concentration of asymmetric dimethylarginine (ADMA) predicts cardiovascular morbidity and mortality in type 1 diabetic patients with diabetic nephropathy

    DEFF Research Database (Denmark)

    Lajer, M.; Tarnow, L.; Jorsal, A.;

    2008-01-01

    OBJECTIVE: To investigate whether circulating asymmetric dimethylarginine (ADMA) levels are predictive of cardiovascular events, decline in glomerular filtration rate (GFR), end-stage renal disease (ESRD), and all-cause mortality in type 1 diabetic patients. RESEARCH DESIGN AND METHODS: We...... performed a prospective observational follow-up study including 397 type 1 diabetic patients with overt diabetic nephropathy (243 men aged 42.1 +/- 10.5 years, GFR 76 +/- 34 ml/min per 1.73 m(2)) and a control group of 175 patients with longstanding type 1 diabetes and persistent normoalbuminuria (104 men...... aged 42.7 +/- 9.7 years, duration of diabetes 27.7 +/- 8.3 years). Patients were followed for a median 11.3 years (range 0.0-12.9) with yearly measurements of GFR ((51)Cr-EDTA plasma clearance) in patients with diabetic nephropathy. Endpoints were fatal and nonfatal cardiovascular disease (CVD...

  10. Exogenous Asymmetric Dimethylarginine (ADMA in Pathogenesis of Ischemia-Reperfusion-Induced Gastric Lesions: Interaction with Protective Nitric Oxide (NO and Calcitonin Gene-Related Peptide (CGRP

    Directory of Open Access Journals (Sweden)

    Marcin Magierowski

    2014-03-01

    Full Text Available Asymmetric dimethylarginine (ADMA is an endogenous nitric oxide (NO synthesis inhibitor and pro-inflammatory factor. We investigated the role of ADMA in rat gastric mucosa compromised through 30 min of gastric ischemia (I and 3 h of reperfusion (R. These I/R animals were pretreated with ADMA with or without the combination of l-arginine, calcitonin gene-related peptide (CGRP or a small dose of capsaicin, all of which are known to afford protection against gastric lesions, or with a farnesoid X receptor (FXR agonist, GW 4064, to increase the metabolism of ADMA. In the second series, ADMA was administered to capsaicin-denervated rats. The area of gastric damage was measured with planimetry, gastric blood flow (GBF was determined by H2-gas clearance, and plasma ADMA and CGRP levels were determined using ELISA and RIA. ADMA significantly increased I/R-induced gastric injury while significantly decreasing GBF, the luminal NO content, and the plasma level of CGRP. This effect of ADMA was significantly attenuated by pretreatment with CGRP, l-arginine, capsaicin, or a PGE2 analogue. In GW4064 pretreated animals, the I/R injury was significantly reduced and this effect was abolished by co-treatment with ADMA. I/R damage potentiated by ADMA was exacerbated in capsaicin-denervated animals with a further reduction of CGRP. Plasma levels of IL-10 were significantly decreased while malonylodialdehyde (MDA and plasma TNF-α contents were significantly increased by ADMA. In conclusion, ADMA aggravates I/R-induced gastric lesions due to a decrease of GBF, which is mediated by a fall in NO and CGRP release, and the enhancement of lipid peroxidation and its pro-inflammatory properties.

  11. Exogenous asymmetric dimethylarginine (ADMA) in pathogenesis of ischemia-reperfusion-induced gastric lesions: interaction with protective nitric oxide (NO) and calcitonin gene-related peptide (CGRP).

    Science.gov (United States)

    Magierowski, Marcin; Jasnos, Katarzyna; Sliwowski, Zbigniew; Surmiak, Marcin; Krzysiek-Maczka, Gracjana; Ptak-Belowska, Agata; Kwiecien, Slawomir; Brzozowski, Tomasz

    2014-01-01

    Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthesis inhibitor and pro-inflammatory factor. We investigated the role of ADMA in rat gastric mucosa compromised through 30 min of gastric ischemia (I) and 3 h of reperfusion (R). These I/R animals were pretreated with ADMA with or without the combination of L-arginine, calcitonin gene-related peptide (CGRP) or a small dose of capsaicin, all of which are known to afford protection against gastric lesions, or with a farnesoid X receptor (FXR) agonist, GW 4064, to increase the metabolism of ADMA. In the second series, ADMA was administered to capsaicin-denervated rats. The area of gastric damage was measured with planimetry, gastric blood flow (GBF) was determined by H2-gas clearance, and plasma ADMA and CGRP levels were determined using ELISA and RIA. ADMA significantly increased I/R-induced gastric injury while significantly decreasing GBF, the luminal NO content, and the plasma level of CGRP. This effect of ADMA was significantly attenuated by pretreatment with CGRP, L-arginine, capsaicin, or a PGE2 analogue. In GW4064 pretreated animals, the I/R injury was significantly reduced and this effect was abolished by co-treatment with ADMA. I/R damage potentiated by ADMA was exacerbated in capsaicin-denervated animals with a further reduction of CGRP. Plasma levels of IL-10 were significantly decreased while malonylodialdehyde (MDA) and plasma TNF-α contents were significantly increased by ADMA. In conclusion, ADMA aggravates I/R-induced gastric lesions due to a decrease of GBF, which is mediated by a fall in NO and CGRP release, and the enhancement of lipid peroxidation and its pro-inflammatory properties. PMID:24658439

  12. The transporter and permeability interactions of asymmetric dimethylarginine (ADMA) and L-arginine with the human blood-brain barrier in vitro.

    Science.gov (United States)

    Watson, Christopher P; Pazarentzos, Evangelos; Fidanboylu, Mehmet; Padilla, Beatriz; Brown, Rachel; Thomas, Sarah A

    2016-10-01

    The blood-brain barrier (BBB) is a biological firewall that carefully regulates the cerebral microenvironment by acting as a physical, metabolic and transport barrier. This selectively permeable interface was modelled using the immortalised human cerebral microvascular endothelial cell line (hCMEC/D3) to investigate interactions with the cationic amino acid (CAA) L-arginine, the precursor for nitric oxide (NO), and with asymmetric dimethylarginine (ADMA), an endogenously derived analogue of L-arginine that potently inhibits NO production. The transport mechanisms utilised by L-arginine are known but they are not fully understood for ADMA, particularly at the BBB. This is of clinical significance giving the emerging role of ADMA in many brain and cerebrovascular diseases and its potential as a therapeutic target. We discovered that high concentrations of ADMA could induce endothelial dysfunction in the hCMEC/D3s BBB permeability model, leading to an increase in paracellular permeability to the paracellular marker FITC-dextran (40kDa). We also investigated interactions of ADMA with a variety of transport mechanisms, comparing the data with L-arginine interactions. Both molecules are able to utilise the CAA transport system y(+). Furthermore, the expression of CAT-1, the best known protein from this group, was confirmed in the hCMEC/D3s. It is likely that influx systems, such as y(+)L and b(0,+), have an important physiological role in ADMA transport at the BBB. These data are not only important with regards to the brain, but apply to other microvascular endothelia where ADMA is a major area of investigation. PMID:27431938

  13. Plasma asymmetric dimethylarginine concentrations in sickle cell disease are related to the hemolytic phenotype

    NARCIS (Netherlands)

    Landburg, P. P.; Teerlink, T.; Biemond, B. J.; Brandjes, D. P. M.; Muskiet, F. A. J.; Duits, A. J.; Schnog, J. B.; Grp, C. U. R. A. M. A. Study

    2010-01-01

    Asymmetric dimethylarginine (ADMA) is associated with pulmonary hypertension (PHT) in sickle cell disease (SCD). We studied the relationship of ADMA to other SCD-related complications. Plasma ADMA and associated parameters were determined in 52 HbSS/HbS beta(0)-thalassemia and 24 HbSC/HbS beta(+)-th

  14. Coordinated Regulation of Dimethylarginine Dimethylaminohydrolase-1 and Cationic Amino Acid Transporter-1 by Farnesoid X Receptor in Mouse Liver and Kidney and Its Implication in the Control of Blood Levels of Asymmetric Dimethylarginine

    OpenAIRE

    Li, Jiang; Wilson, Annette; Gao, Xiang; Kuruba, Ramalinga; Liu, Youhua; Poloyac, Samuel; Pitt, Bruce; Xie, Wen; Li, Song

    2009-01-01

    Asymmetric dimethylarginine (ADMA) is a potent endogenous inhibitor of endothelial nitric-oxide synthase (eNOS), and increased plasma concentrations of ADMA have been regarded as a risk factor for a number of cardiovascular diseases. Circulating ADMA is largely taken up by liver and kidney via system y+ carriers of the cationic amino acid (CAT) family and subsequently metabolized by dimethylarginine dimethylaminohydrolases (DDAHs). As such, agents targeted at enhancing ADMA metabolism may pro...

  15. Asymmetric dimethylarginine in somatically healthy schizophrenia patients treated with atypical antipsychotics

    DEFF Research Database (Denmark)

    Jørgensen, Anders; Knorr, Ulla Benedichte Søsted; Soendergaard, Mia Greisen;

    2015-01-01

    and the L-arginine:ADMA ratio showed no correlations with oxidative stress markers, medication load, or Positive and Negative Syndrome Scale scores. CONCLUSIONS: Schizophrenia and treatment with AAP was not associated with increased levels of plasma ADMA or the L-arginine:ADMA ratio. Furthermore, plasma......BACKGROUND: Schizophrenia is associated with increased cardiovascular morbidity and mortality. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of the nitric oxide synthase, and the L-arginine:ADMA ratio are markers of endothelial dysfunction that predict mortality and adverse outcome...... in a range of cardiovascular disorders. Increased ADMA levels may also lead to increased oxidative stress. We hypothesized that ADMA and the L-arginine:ADMA ratio are increased in somatically healthy schizophrenia patients treated with atypical antipsychotics (AAP), and that the ADMA and the L-arginine: ADMA...

  16. Asymmetric dimethylarginine: A novel biomarker of gastric mucosal injury?

    Institute of Scientific and Technical Information of China (English)

    Zhe Zhang; Yi-You Zou; Fu-Jun Li; Chang-Ping Hu

    2011-01-01

    Nitric oxide (NO),a multifunctional endogenous gas molecule,is metabolized from L-arginine by enzymatic reaction in the presence of nitric oxide synthase. NO,an important gas signaling molecule,is a gastric mucosa protective factor that contributes significantly to maintain normal gastric mucosa integrity. NO increases gastric mucosa blood flow,regulates the secretion of mucus and bicarbonate,and inhibits the secretion of gastric juice. Asymmetric dimethylarginine (ADMA) has been identified as the major endogenous inhibitor of nitric oxide synthase. The function of ADMA is to decrease NO production via inhibiting nitric oxide synthase activity. Besides inhibiting NO synthesis,ADMA also directly induces oxidative stress and cell apoptosis,and participates in inflammation reaction. Its systemic accumulation was observed in conjunction with several cardiovascular and metabolic diseases. ADMA also mediates gastric ulcer injury induced by ethanol,stress,helicobacter pylori and indomethacin. The mechanism of ADMA directly producing adverse effect in gastric mucosa is incompletely understood. It is widely accepted that NO bioavailability decrease is the majority reason. Promotion of apoptosis and aggravation of inflammation may be other important mechanisms of ADMA-induced gastric injury. ADMA might be a novel clinical and experimental biomarker related to gastric mucosa disorder. Although therapeutic tool targeting to ADMA is available in multiple cardiovascular diseases,it is unknown in gastrointestinal disease. The strategy to inhibit ADMA is beneficial to gastric ulcer induced by ethanol in rats. Thus,ADMA might be a candidate of therapeutic target in gastric mucosa damage.

  17. Asymmetric dimethylarginine, endothelial nitric oxide bioavailability and mortality in sepsis.

    Directory of Open Access Journals (Sweden)

    Joshua S Davis

    Full Text Available BACKGROUND: Plasma concentrations of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase, are raised in patients with chronic vascular disease, causing increased cardiovascular risk and endothelial dysfunction, but the role of ADMA in acute inflammatory states is less well defined. METHODS AND RESULTS: In a prospective longitudinal study in 67 patients with acute sepsis and 31 controls, digital microvascular reactivity was measured by peripheral arterial tonometry and blood was collected at baseline and 2-4 days later. Plasma ADMA and L-arginine concentrations were determined by high performance liquid chromatography. Baseline plasma L-arginine: ADMA ratio was significantly lower in sepsis patients (median [IQR] 63 [45-103] than in hospital controls (143 [123-166], p<0.0001 and correlated with microvascular reactivity (r = 0.34, R(2 = 0.12, p = 0.02. Baseline plasma ADMA was independently associated with 28-day mortality (Odds ratio [95% CI] for death in those in the highest quartile (≥ 0.66 µmol/L = 20.8 [2.2-195.0], p = 0.008, and was independently correlated with severity of organ failure. Increase in ADMA over time correlated with increase in organ failure and decrease in microvascular reactivity. CONCLUSIONS: Impaired endothelial and microvascular function due to decreased endothelial NO bioavailability is a potential mechanism linking increased plasma ADMA with organ failure and death in sepsis.

  18. Association Between Asymmetric Dimethylarginine and the Severity of Coronary Artery Disease in Patients with Chronic Kidney Disease

    OpenAIRE

    Yusuf SELCOKİ; Aydin, Murat; Mustafa İKİZEK; Armutcu, Ferah; Eryonucu, Beyhan; Kanbay, Mehmet

    2011-01-01

    OBJECTIVE: Cardiovascular diseases are the most common cause of death in patients with endstage renal disease. Asymmetrical dimethylarginine (ADMA) is increased in conditions associated with increased risk of atherosclerosis. We aimed to examine the association between severity of coronary stenosis and the ADMA levels in a group of chronic kidney disease (CKD) stage 1 to 3. MATERIAL and METHODS: Eighty-eight (88) consecutive patients with decreased renal function (glomerular filtration rat...

  19. Relationship between asymmetric dimethylarginine and endothelial dysfunction in patients with rheumatoid arthritis

    Science.gov (United States)

    Şentürk, Taşkın; Yılmaz, Nergiz; Sargın, Gökhan; Köseoğlu, Kutsi; Yenisey, Çiğdem

    2016-01-01

    Objective In rheumatoid arthritis (RA), endothelial dysfunction caused by the inflammatory process increases the risk of cardiovascular disease. Asymmetric Dimethylarginine (ADMA) leads to vascular dysfunction, whereas atherosclerosis and increased ADMA is associated with cardiovascular disease risk factors. Flow-mediated Dilation (FMD) is a radiological method to demonstrate endothelial dysfunction. In the present study, we assessed the availability of ADMA as a marker for endothelial dysfunction in RA patients. ADMA can be used as a simple and cheaper method for the determination of endothelial dysfunction. Material and Methods Forty patients (1 male, 39 female) diagnosed with RA according to the classification criteria and 29 healthy volunteers (2 males, 27 females) were included in this study. ADMA was studied by enzyme-linked immunosorbent assay (ELISA). Chi-square, Fisher’s exact test, Mann–Whitney U test, and Spearman’s correlation tests were used for analytical analysis, and p<0.05 was considered as the level of statistical significance. Results In our study, ADMA levels were significantly higher in RA patients. The ADMA level was inversely correlated with FMD. Although high levels of both C-reactive protein and ADMA were detected in patients with high disease activity, there was no statistically significant difference between these parameters (p=0.18). There were statistically significant negative correlations between FMD and age and disease duration (p=0.01, p=0.01). However, there were no statistically significant correlations with erythrocyte sedimentation rate, rheumatoid factor, and disease activity score (p=0.68). In RA patients, there was a statistically significant positive correlation between disease duration and ADMA, whereas a negative correlation was found between FMD and ADMA (p<0.05). Conclusion Our results support the hypothesis that ADMA may be used in the assessment of endothelial dysfunction in patients with RA. It will be cost

  20. Collagen synthesis, nitric oxide and asymmetric dimethylarginine in diabetic subjects undergoing hyperbaric oxygen therapy

    OpenAIRE

    Gürdöl, Figen; Cimsit, M; Öner-Iyidoğan, Yıldız; Koçak, Hikmet; Sengun, S; Yalçınkaya-Demirsöz, S

    2010-01-01

    The main pathological condition in patients with impaired wound healing is diabetes mellitus. These patients have significantly low circulating nitric oxide (NO) levels because the stimulatory action of insulin on NO synthesis is absent. Additionally, asymmetric dimethylarginine (ADMA), an inhibitor of NO synthase, is increased owing to the generation of oxidative stress. NO was thought to contribute to wound healing. Hyperbaric oxygen (HBO) treatment is generally used in order to accelerate ...

  1. The correlation of serum asymmetric dimethylarginine and anti-Müllerian hormone in primary dysmenorrhea.

    Science.gov (United States)

    Akdemir, Nermin; Cinemre, Fatma Behice; Bostancı, Mehmet Sühha; Cinemre, Hakan; Ünal, Orhan; Ozden, Selçuk; Cevrioglu, Arif Serhan; Kacal, Zubeyde; Akdemir, Ramazan

    2016-08-01

    In this study, we aimed to investigate the association of serum asymmetric dimethylarginine (ADMA) and anti-Müllerian hormone (AMH) levels in primary dysmenorrhea patients. The study employed a cross-sectional design. Eighty-nine female university students with primary dysmenorrhea were included in the study. All patients underwent complete clinical and laboratory investigations, including serum ADMA, AMH levels, pelvic ultrasonography, electrocardiography, and echocardiography. Pearson correlation and linear regression analysis were used to evaluate associations between continuous data. Categorical associations were evaluated using χ(2) test. Correlation analysis between serum ADMA and AMH levels in the study group showed a highly significant positive relationship (Pearson correlation = 0.978, p = 0.01). Our study has shown a significant positive correlation between serum ADMA and AMH levels in primary dysmenorrhea. Serum ADMA levels may have the potential to demonstrate ovarian reserve. PMID:27523455

  2. Asymmetric dimethylarginine exacerbates Aβ-induced toxicity and oxidative stress in human cell and Caenorhabditis elegans models of Alzheimer disease.

    Science.gov (United States)

    Luo, Yunfeng; Yue, Wenhui; Quan, Xin; Wang, Yue; Zhao, Baolu; Lu, Zhongbing

    2015-02-01

    Growing evidence suggests a strong association between cardiovascular risk factors and incidence of Alzheimer disease (AD). Asymmetric dimethylarginine (ADMA), the endogenous nitric oxide synthase inhibitor, has been identified as an independent cardiovascular risk factor and is also increased in plasma of patients with AD. However, whether ADMA is involved in the pathogenesis of AD is unknown. In this study, we found that ADMA content was increased in a transgenic Caenorhabditis elegans β-amyloid (Aβ) overexpression model, strain CL2006, and in human SH-SY5Y cells overexpressing the Swedish mutant form of human Aβ precursor protein (APPsw). Moreover, ADMA treatment exacerbated Aβ-induced paralysis and oxidative stress in CL2006 worms and further elevated oxidative stress and Aβ secretion in APPsw cells. Knockdown of type 1 protein arginine N-methyltransferase to reduce ADMA production failed to show a protective effect against Aβ toxicity, but resulted in more paralysis in CL2006 worms as well as increased oxidative stress and Aβ secretion in APPsw cells. However, overexpression of dimethylarginine dimethylaminohydrolase 1 (DDAH1) to promote ADMA degradation significantly attenuated oxidative stress and Aβ secretion in APPsw cells. Collectively, our data support the hypothesis that elevated ADMA contributes to the pathogenesis of AD. Our findings suggest that strategies to increase DDAH1 activity in neuronal cells may be a novel approach to attenuating AD development.

  3. Plasma asymmetric dimethylarginine and adverse events in patients with atrial fibrillation referred for coronary angiogram.

    Directory of Open Access Journals (Sweden)

    Tze-Fan Chao

    Full Text Available OBJECTIVES: Elevated plasma levels of asymmetric dimethylarginine (ADMA have been reported to be associated with endothelial dysfunction, inflammation, and oxidative stress in multiple cardiovascular diseases. This study aimed to investigate whether ADMA was a predictor of clinical outcomes in atrial fibrillation (AF. METHODS AND RESULTS: From 2006-2009, 990 individuals were referred to our institution for coronary angiography. Among these patients, 141 subjects with a diagnosis of AF, including 52 paroxysmal AF (PAF and 89 non-paroxysmal AF (non-PAF patients, were identified as the study population. Plasma ADMA levels were measured. An adverse event was defined as the occurrence of ischemic stroke or cardiovascular death. The ADMA levels were higher in AF than non-AF patients (0.50 ± 0.13 versus 0.45 ± 0.07 µmol/L; p<0.001. Besides, non-PAF patients had higher ADMA levels than PAF patients (0.52 ± 0.15 versus 0.48 ± 0.08 µmol/L; p<0.001. During the follow-up of 30.7±14.4 months, 21 patients (14.9% experienced adverse events, including cardiovascular death in 7 patients and ischemic stroke in 14. ADMA level, CHA2DS2-VASc score, and left atrial diameter were independent predictors of adverse events in the multivariate analysis. At a cutoff-value of 0.55 µmol/L, the Kaplan-Meier survival analysis showed that patients with a high ADMA level had a higher event rate during the follow-up period. CONCLUSIONS: A higher level of ADMA was a risk factor of adverse events in AF patients, which was independent from the CHA2DS2-VASc score. It deserves to further study whether ADMA could potentially refine the clinical risk stratification in AF.

  4. Asymmetric dimethylarginine triggers macrophage apoptosis via the endoplasmic reticulum stress pathway.

    Science.gov (United States)

    Hong, Dan; Gao, Hai-Chao; Wang, Xiang; Li, Ling-Fang; Li, Chuan-Chang; Luo, Ying; Wang, Kang-Kai; Bai, Yong-Ping; Zhang, Guo-Gang

    2015-01-01

    Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), is emerging as a key contributing factor in atherogenesis, a process in turn known to involve macrophage apoptosis. The aim of this study was to determine the effect of ADMA on macrophage apoptosis, with specific reference to the endoplasmic reticulum (ER) stress pathway. Macrophage apoptosis was evaluated by Annexin V- Propidium iodide (PI) and Hoechst 33258 staining assays. Levels of the ER stress marker glucose regulated protein 78 (GRP78) were characterized by western blot. Levels of the proapoptotic C/EBP-homologous protein (CHOP) were evaluated by western blot and reverse transcription polymerase chain reaction (RT-PCR), and caspase-4 activity was measured using a colorimetric protease assay kit. We observed ADMA dose- and time-dependent increases in macrophage levels of GRP78. Similar ADMA dose- and time-dependent increases were detected in intracellular caspase-4 activity and macrophage apoptosis, all of which were sensitive to treatment with siRNAs for protein kinase RNA-like ER kinase and inositol-requiring protein-1 (IRE1), the ADMA antagonist L-arginine, as well as inhibitors of eukaryotic translation initiation factor-2 (salubrinal), IRE1 (irestatin 9389), and c-Jun N-terminal kinase (SP600125). Our results indicate that ADMA triggers macrophage apoptosis via the ER stress pathway. PMID:25209804

  5. The association between progression of atherosclerosis and the methylated amino acids asymmetric dimethylarginine and trimethyllysine.

    Directory of Open Access Journals (Sweden)

    Kjetil H Løland

    Full Text Available OBJECTIVE: We previously showed that treatment with folic acid (FA/B12 was associated with more rapid progression of coronary artery disease (CAD. High doses of FA may induce methylation by increasing the availability of S-adenosyl-methionine (SAM. Asymmetric dimethylarginine (ADMA and trimethyllysine (TML are both produced through proteolytic release following post-translational SAM-dependent methylation of precursor amino acid. ADMA has previously been associated with CAD. We investigated if plasma levels of ADMA and TML were associated with progression of CAD as measured by quantitative coronary angiography (QCA. METHODS: 183 patients from the Western Norway B Vitamin Intervention Trial (WENBIT undergoing percutaneous coronary intervention (PCI were randomized to daily treatment with 0.8 mg FA/0.4 mg B12 with and without 40 mg B6, B6 alone or placebo. Coronary angiograms and plasma samples of ADMA and TML were obtained at both baseline and follow-up (median 10.5 months. The primary end-point was progression of CAD as measured by diameter stenosis (DS evaluated by linear quantile mixed models. RESULTS: A total of 309 coronary lesions not treated with PCI were identified. At follow-up median (95% CI DS increased by 18.35 (5.22-31.49 percentage points per µmol/L ADMA increase (p-value 0.006 and 2.47 (0.37-4.58 percentage points per µmol/L TML increase (p-value 0.021 in multivariate modeling. Treatment with FA/B12 (±B6 was not associated with ADMA or TML levels. CONCLUSION: In patients with established CAD, baseline ADMA and TML was associated with angiographic progression of CAD. However, neither ADMA nor TML levels were altered by treatment with FA/B12 (±B6. TRIAL REGISTRATION: Controlled-Trials.com NCT00354081.

  6. High plasma concentrations of asymmetric dimethylarginine inhibit ischemic cardioprotection in hypercholesterolemic rats

    Energy Technology Data Exchange (ETDEWEB)

    Landim, M.B.P.; Dourado, P.M.M.; Casella-Filho, A.; Chagas, A.C.P.; Luz, P.L. da [Unidade de Aterosclerose, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2013-05-10

    A low concentration of nitric oxide associated with a high concentration of asymmetric dimethylarginine (ADMA) can explain the lack of ischemic cardioprotection observed in the presence of hypercholesterolemia. The objective of the present study was to evaluate the effect of hypercholesterolemia on ischemic pre- and postconditioning and its correlation with plasma concentrations of ADMA. Male Wistar rats (6-8 weeks old) fed a 2% cholesterol diet (n = 21) for 8 weeks were compared to controls (n = 25) and were subjected to experimental myocardial infarction and reperfusion, with ischemic pre- and postconditioning. Total cholesterol and ADMA were measured in plasma before the experimental infarct and the infarct area was quantified. Weight, total cholesterol and plasma ADMA (means ± SE; 1.20 ± 0.06, 1.27 ± 0.08 and 1.20 ± 0.08 vs 0.97 ± 0.04, 0.93 ± 0.05 and 0.97 ± 0.04 µM) were higher in animals on the hypercholesterolemic diet than in controls, respectively. Cardioprotection did not reduce infarct size in the hypercholesterolemic animals (pre: 13.55% and post: 8% compared to 7.95% observed in the group subjected only to ischemia and reperfusion), whereas infarct size was reduced in the animals on a normocholesterolemic diet (pre: 8.25% and post: 6.10% compared to 12.31%). Hypercholesterolemia elevated ADMA and eliminated the cardioprotective effects of ischemic pre- and postconditioning in rats.

  7. High plasma concentrations of asymmetric dimethylarginine inhibit ischemic cardioprotection in hypercholesterolemic rats

    International Nuclear Information System (INIS)

    A low concentration of nitric oxide associated with a high concentration of asymmetric dimethylarginine (ADMA) can explain the lack of ischemic cardioprotection observed in the presence of hypercholesterolemia. The objective of the present study was to evaluate the effect of hypercholesterolemia on ischemic pre- and postconditioning and its correlation with plasma concentrations of ADMA. Male Wistar rats (6-8 weeks old) fed a 2% cholesterol diet (n = 21) for 8 weeks were compared to controls (n = 25) and were subjected to experimental myocardial infarction and reperfusion, with ischemic pre- and postconditioning. Total cholesterol and ADMA were measured in plasma before the experimental infarct and the infarct area was quantified. Weight, total cholesterol and plasma ADMA (means ± SE; 1.20 ± 0.06, 1.27 ± 0.08 and 1.20 ± 0.08 vs 0.97 ± 0.04, 0.93 ± 0.05 and 0.97 ± 0.04 µM) were higher in animals on the hypercholesterolemic diet than in controls, respectively. Cardioprotection did not reduce infarct size in the hypercholesterolemic animals (pre: 13.55% and post: 8% compared to 7.95% observed in the group subjected only to ischemia and reperfusion), whereas infarct size was reduced in the animals on a normocholesterolemic diet (pre: 8.25% and post: 6.10% compared to 12.31%). Hypercholesterolemia elevated ADMA and eliminated the cardioprotective effects of ischemic pre- and postconditioning in rats

  8. Interleukin-6 and asymmetric dimethylarginine are associated with platelet activation after percutaneous angioplasty with stent implantation.

    Science.gov (United States)

    Gremmel, Thomas; Perkmann, Thomas; Kopp, Christoph W; Seidinger, Daniela; Eichelberger, Beate; Koppensteiner, Renate; Steiner, Sabine; Panzer, Simon

    2015-01-01

    Data linking in vivo platelet activation with inflammation and cardiovascular risk factors are scarce. Moreover, the interrelation between endothelial dysfunction as early marker of atherosclerosis and platelet activation has not been studied, so far. We therefore sought to investigate the associations of inflammation, endothelial dysfunction and cardiovascular risk factors with platelet activation and monocyte-platelet aggregate (MPA) formation in 330 patients undergoing angioplasty with stent implantation for atherosclerotic cardiovascular disease. P-selectin expression, activation of glycoprotein IIb/IIIa and MPA formation were determined by flow cytometry. Interleukin (IL)-6, high sensitivity C-reactive protein and asymmetric dimethylarginine (ADMA) were measured by commercially available assays. IL-6 was the only parameter which was independently associated with platelet P-selectin expression and activated GPIIb/IIIa as well as with leukocyte-platelet interaction in multivariate regression analysis (all p<0.05). ADMA was independently associated with GPIIb/IIIa activation (p<0.05). Patients with high IL-6 exhibited a significantly higher expression of P-selectin than patients with low IL-6 (p=0.001), whereas patients with high ADMA levels showed a more pronounced activation of GPIIb/IIIa than patients with low ADMA (p=0.003). In conclusion, IL-6 and ADMA are associated with platelet activation after percutaneous angioplasty with stent implantation. It remains to be established whether they act prothrombotic and atherogenic themselves or are just surrogate markers for atherosclerosis with concomitant platelet activation.

  9. Interleukin-6 and asymmetric dimethylarginine are associated with platelet activation after percutaneous angioplasty with stent implantation.

    Directory of Open Access Journals (Sweden)

    Thomas Gremmel

    Full Text Available Data linking in vivo platelet activation with inflammation and cardiovascular risk factors are scarce. Moreover, the interrelation between endothelial dysfunction as early marker of atherosclerosis and platelet activation has not been studied, so far. We therefore sought to investigate the associations of inflammation, endothelial dysfunction and cardiovascular risk factors with platelet activation and monocyte-platelet aggregate (MPA formation in 330 patients undergoing angioplasty with stent implantation for atherosclerotic cardiovascular disease. P-selectin expression, activation of glycoprotein IIb/IIIa and MPA formation were determined by flow cytometry. Interleukin (IL-6, high sensitivity C-reactive protein and asymmetric dimethylarginine (ADMA were measured by commercially available assays. IL-6 was the only parameter which was independently associated with platelet P-selectin expression and activated GPIIb/IIIa as well as with leukocyte-platelet interaction in multivariate regression analysis (all p<0.05. ADMA was independently associated with GPIIb/IIIa activation (p<0.05. Patients with high IL-6 exhibited a significantly higher expression of P-selectin than patients with low IL-6 (p=0.001, whereas patients with high ADMA levels showed a more pronounced activation of GPIIb/IIIa than patients with low ADMA (p=0.003. In conclusion, IL-6 and ADMA are associated with platelet activation after percutaneous angioplasty with stent implantation. It remains to be established whether they act prothrombotic and atherogenic themselves or are just surrogate markers for atherosclerosis with concomitant platelet activation.

  10. Changes in serum asymmetric dimethylarginine and endothelial markers levels with varying periods of hemodialysis.

    Science.gov (United States)

    Yaman, Alper; Karabag, Funda; Demir, Serap; Koken, Tulay

    2014-08-01

    Asymmetric dimethylarginine (ADMA) as a uremia toxin is accumulated in end-stage renal disease (ESRD) patients. Elevated ADMA level has been shown to be predictive of cardiovascular diseases (CVDs) and all-cause mortality in ESRD. Therefore, we investigated the effect of prolonged hemodialysis (HD) treatment on the levels of serum ADMA, arginine, nitric oxide (NO), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1). Seventy-five patients (M/F = 40/35) with chronic renal failure (CRF) and who were on HD were divided into five groups with differing treatment periods of HD; from 6 to 24 months to 97-120 months. Fifteen apparently healthy subjects acted as controls. The serum levels of ADMA, sICAM-1 and sVCAM-1 were increased in all patient groups compared to the control group. No significant difference was observed when the patient groups were compared in terms of HD treatment periods. Nitric oxide levels were lower in the three groups who were treated for periods of 49-72, 73-96, 97-120 months compared to the control group. The L-arginine to ADMA ratio was decreased in all patient groups compared to controls. Consequently, our investigations have shown that in HD continued for more than 4 years NO levels began to decrease significantly and the levels of serum ADMA, sICAM-1 and sVCAM-1 levels increased although this increase was not affected by the period in which hemodialysis treatment was applied.

  11. Relationship of Asymmetrical Dimethylarginine, Nitric Oxide, and Sustained Attention during Attack in Patients with Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Serpil Canpolat

    2014-01-01

    Full Text Available We investigated the relationship of serum nitric oxide (NO and asymmetrical dimethylarginine (ADMA levels with cognitive functioning in patients with major depressive disorder (MDD. 41 MDD patients (Beck depression scale scores >16 and 44 controls were included in the study. Rey verbal learning and memory test, auditory consonant trigram test, digit span test, Wisconsin card sorting test, continuous performance task (TOVA, and Stroop test scores were found to be impaired in patients with major depressive disorder when compared to healthy controls. There was no significant difference between patient and control groups in terms of serum NO and ADMA. Serum NO levels were correlated with TOVA test error scores and Stroop test time scores, whereas serum ADMA levels were negatively correlated with TOVA test error scores. Metabolic detriments especially in relation to NO metabolism in frontal cortex and hypothalamus, psychomotor retardation, or loss of motivation may explain these deficits.

  12. ADMA metabolism and clearance

    OpenAIRE

    Teerlink, Tom

    2005-01-01

    Abstract The plasma concentration of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is the resultant of many processes at cellular and organ levels. Post-translational methylation of arginine residues of pro teins plays a crucial role in the regulation of their functions, which include processes such as transcription, translation and RNA splicing. Because protein methylation is irreversible, the methylation signal can be turned off only by pro...

  13. Evaluation of serum asymmetric dimethylarginine levels in patients with psoriasis vulgaris

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    Recep Bilgiç

    2015-12-01

    Full Text Available Background and Design: In this study, we aimed to evaluate the serum asymmetric dimethylarginine (ADMA levels and investigate the relationship between the severity of the disease and other cardiovascular risk factors in patients with psoriasis. Materials and Methods: This is a prospective, single-center, and controlled clinical study. Forty male patients with psoriasis and forty healthy male volunteers were included in the study. The psoriasis area severity index (PASI was used for evaluating the disease severity. Results: Forty consecutive male patients with psoriasis aged between 20 and 41 years (mean: 26.03±6.55 as study group and forty healthy male volunteers aged between 20 and 32 years (mean: 23.40±3.57 as control group were included in the study. There was no statistically significant difference in ADMA, homocysteine, vitamin B12, high density lipoprotein (HDL, and antithrombin III levels between the study and control groups. In psoriatic group, a mean 1.19-fold increase was observed in the serum ADMA levels in association with increased severity of PASI scores but it was not statistically significant. In the patient group, waist circumference (p=0.03, total cholesterol (p=0.007, low density lipoprotein (LDL cholesterol (p=0.014 and fibrinogen (p=0.049 levels were higher and folic acid (p=0.04 levels were lower than in the control group. In terms of laboratory parameters, a significant negative relationship between ADMA and HDL (p=0.045, and LDL (p=0.04 and total cholesterol (p=0.01 was found only in the control group. Conclusion: It seems that psoriasis with concomitant atherogenic dyslipidemia, enflammation and tendency to obesity is an independent risk factor for cardiovascular diseases and this risk seems to be present since earlier ages in correlation with disease severity. Extensive studies are needed to clearly demonstrate the relationship between this situation and serum ADMA levels in patients with psoriasis

  14. Activities of asymmetric dimethylarginine-related enzymes in white adipose tissue are associated with circulating lipid biomarkers

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    Iwasaki Hiroaki

    2012-04-01

    Full Text Available Abstract Background Asymmetric NG,NG-dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase, is regulated by the enzymatic participants of synthetic and metabolic processes, i.e., type I protein N-arginine methyltransferase (PRMT and dimethylarginine dimethylaminohydrolase (DDAH. Previous reports have demonstrated that circulating ADMA levels can vary in patients with type 1 and type 2 diabetes mellitus (T2DM. White adipose tissue expresses the full enzymatic machinery necessary for ADMA production and metabolism; however, modulation of the activities of adipose ADMA-related enzymes in T2DM remains to be determined. Methods A rodent model of T2DM using 11- and 20-week old Goto-Kakizaki (GK rats was used. The expression and catalytic activity of PRMT1 and DDAH1 and 2 in the white adipose tissues (periepididymal, visceral and subcutaneous fats and femur skeletal muscle tissue were determined by immunoblotting, in vitro methyltransferase and in vitro citrulline assays. Results Non-obese diabetic GK rats showed low expression and activity of adipose PRMT1 compared to age-matched Wistar controls. Adipose tissues from the periepididymal, visceral and subcutaneous fats of GK rats had high DDAH1 expression and total DDAH activity, whereas the DDAH2 expression was lowered below the control value. This dynamic of ADMA-related enzymes in white adipose tissues was distinct from that of skeletal muscle tissue. GK rats had lower levels of serum non-esterified fatty acids (NEFA and triglycerides (TG than the control rats. In all subjects the adipose PRMT1 and DDAH activities were statistically correlated with the levels of serum NEFA and TG. Conclusion Activities of PRMT1 and DDAH in white adipose tissues were altered in diabetic GK rats in an organ-specific manner, which was reflected in the serum levels of NEFA and TG. Changes in adipose ADMA-related enzymes might play a part in the function of white adipose tissue.

  15. Low plasma arginine:asymmetric dimethyl arginine ratios predict mortality after intracranial aneurysm rupture

    DEFF Research Database (Denmark)

    Staalsø, Jonatan Myrup; Bergström, Anita; Edsen, Troels;

    2013-01-01

    Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthases, predicts mortality in cardiovascular disease and has been linked to cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). In this prospective study, we assessed whether circulating ADMA, arginine...

  16. Association Between Asymmetric Dimethylarginine and the Severity of Coronary Artery Disease in Patients with Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Yusuf SELCOKİ

    2011-01-01

    Full Text Available OBJECTIVE: Cardiovascular diseases are the most common cause of death in patients with endstage renal disease. Asymmetrical dimethylarginine (ADMA is increased in conditions associated with increased risk of atherosclerosis. We aimed to examine the association between severity of coronary stenosis and the ADMA levels in a group of chronic kidney disease (CKD stage 1 to 3. MATERIAL and METHODS: Eighty-eight (88 consecutive patients with decreased renal function (glomerular filtration rate (GFR between 90 and 30 ml/min, undergoing cardiac catheterization for proven or clinically suspected coronary artery disease were enrolled at the study. Serum levels of creatinine, ADMA, nitric oxide (NO, calcium, phosphate, total cholesterol, HDL and LDL fractions, triglycerides were determined using measurement techniques. The Gensini scoring system was used for the detection of the severity of coronary atherosclerosis. RESULTS: The mean serum values were 81.48 ± 13.8 micromol/l for ADMA and 3.7 ± 1.7 mmol/L for NO. The mean Gensini score in the study group was 30.4 ± 40.1. All patients were classified into tertiles of Gensini score level. Patients in the highest tertile had statistically significantly lower GFR values. The ADMA values increased statistically significantly in the third tertile compared with the first tertile. The Gensini score values significantly correlated in univariate analysis with the GFR, ADMA and presence of hypertension. In a multivariate regression model, ADMA was the only statistically significant independent predictor of Gensini score. CONCLUSION: ADMA appears to be one of the strongest risk markers for atherosclerosis in patients with mild and moderate CKD.

  17. Asymmetric Dimethylarginine as a Surrogate Marker of Endothelial Dysfunction and Cardiovascular Risk in Patients with Systemic Rheumatic Diseases

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    George D. Kitas

    2012-09-01

    Full Text Available The last few decades have witnessed an increased life expectancy of patients suffering with systemic rheumatic diseases, mainly due to improved management, advanced therapies and preventative measures. However, autoimmune disorders are associated with significantly enhanced cardiovascular morbidity and mortality not fully explained by traditional cardiovascular disease (CVD risk factors. It has been suggested that interactions between high-grade systemic inflammation and the vasculature lead to endothelial dysfunction and atherosclerosis, which may account for the excess risk for CVD events in this population. Diminished nitric oxide synthesis—due to down regulation of endothelial nitric oxide synthase—appears to play a prominent role in the imbalance between vasoactive factors, the consequent impairment of the endothelial hemostasis and the early development of atherosclerosis. Asymmetric dimethylarginine (ADMA is one of the most potent endogenous inhibitors of the three isoforms of nitric oxide synthase and it is a newly discovered risk factor in the setting of diseases associated with endothelial dysfunction and adverse cardiovascular events. In the context of systemic inflammatory disorders there is increasing evidence that ADMA contributes to the vascular changes and to endothelial cell abnormalities, as several studies have revealed derangement of nitric oxide/ADMA pathway in different disease subsets. In this article we discuss the role of endothelial dysfunction in patients with rheumatic diseases, with a specific focus on the nitric oxide/ADMA system and we provide an overview on the literature pertaining to ADMA as a surrogate marker of subclinical vascular disease.

  18. Correlation of Neopterin and TNF-alpha with Asymmetric Dimethylarginine in Metabolic Syndrome

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    Dedeh Yuniarty

    2011-12-01

    Full Text Available BACKGROUND: A large number of obesity in the community increases the incidence of Metabolic Syndrome (MetS that can increase the risks of heart disease, diabetes, and stroke. One of the possible causes of stroke is atherosclerosis. Atherosclerosis is initiated by the incidence of inflammation and endothelial dysfuction. Atherosclerosis is involved in an ongoing inflammatory response. At the beginning of atherosclerosis, when the endothel become inflamed, it expresses adhesion molecules  that attract monocytes. The monocytes then migrate into the intima due to endothelial dysfunction. Activation of macrophage occurs in the process of inflammation as the earliest type of lesion of atherosclerosis. In this study, monocyte/macrophage activation is marked by Neopterin. In other process of atherosclerosis, vascular nitric oxide (NO activity has a role as a potent endogenous vasodilator. In regulating the vascular tone, NO has a role to suppress vascular smooth muscle proliferation, inhibit platelet adhesion and aggregation, and interferes with the leukocyte-endothelial cell interaction. In MetS, hypercholesterolemia decreases NO activity. Asymmetric Dimethylarginine (ADMA has been characterized as an endogenous, competitive inhibitor of NO synthase. In this study, the incidence of endothelial dysfunction is marked by ADMA. The aim of this study was to discover the role of Neopterin in MetS patients by evaluating the correlation between Neopterin and ADMA in MetS through tumor necrosis factor (TNF-α or direct line. METHODS: The study was cross sectional on 64 males with MetS aged 30-65 years. The measurements of TNF-α concentrations was done, respectively. RESULTS: Neopterin concentration correlated with Log TNF-α concentration (r=0.311, p=0.012. There is no significant correlation between Neopterin and ADMA (r=0.012, p=0.930; ADMA and Log TNF-α (r=0.029, p=0.821. CONCLUSIONS: There is no significant correlation between Neopterin and ADMA through

  19. The Inhibitory Effect of Quercetin on Asymmetric Dimethylarginine-Induced Apoptosis Is Mediated by the Endoplasmic Reticulum Stress Pathway in Glomerular Endothelial Cells

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    Weikang Guo

    2014-01-01

    Full Text Available Asymmetric dimethylarginine (ADMA is considered an independent mortality and cardiovascular risk factor in chronic kidney disease (CKD patients, and contributes to the development of renal fibrosis. Quercetin (QC, a natural component of foods, protects against renal injury. Here, we explored the possible mechanisms that are responsible for ADMA-induced renal fibrosis and the protective effect of QC. We found that ADMA treatment activated the endoplasmic reticulum (ER stress sensor proteins phosphorylated protein kinase RNA-activated-like ER kinase (PERK and inositol requiring-1α (IRE1, which correspondingly induced C/EBP homologous protein (CHOP expression and phosphorylated c-Jun N-terminal kinase (JNK phosphorylation in glomerular endothelial cells (GEnCs. Following this, ADMA promoted ER stress-induced apoptosis and resulted in transforming growth factor β (TGF-β expression in GEnCs. SP600125, an inhibitor of JNK, and CHOP siRNA protected against ADMA-induced cell apoptosis and TGF-β expression. QC prevented ADMA-induced PERK and IRE1 apoptotic ER stress pathway activation. Also, ADMA-induced GEnCs apoptosis and TGF-β expression was reduced by QC. Overexpression of CHOP blocked QC-mediated protection from apoptosis in ER stressed cells. Overall, these observations indicate that ADMA may induce GEnCs apoptosis and TGF-β expression by targeting the PERK-CHOP and IRE1-JNK pathway. In addition, drugs such as QC targeting ER stress may hold great promise for the development of novel therapies against ADMA-induced renal fibrosis.

  20. Development of RI protein chip system for measurement of ADMA as risk factor of liver disease, cardiovascular disease and diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gil Hong; An, Sin Ae; Choi, Hyun Mi; Cheong, Kyung Ah; Chang, Yeon Soo [Korea University, Seoul (Korea, Republic of)

    2010-05-15

    ADMA (asymmetric dimethylarginine) is an endogenous competitive NOS (nitric oxide synthase) inhibitor. Elevation of ADMA level in body fluid is related to various diseases including diabetes mellitus, atherosclerosis, hypercholesterolemia, chronic heart failure, and hypertension. Our goal was to elucidate the role for ADMA and protein arginine methylation in the pathogenesis of diabetes and develop RI protein chip system for easy determination of ADMA levels in blood or tissues. As a result, ADMA regulated by protein arginine methylation, DDAH1, and NOS was demonstrated to play some role in the pathogenesis of diabetes mellitus, and arginine methylation of some proteins indicated their possible involvement in the change in ADMA levels. The concept of the RI protein chip system was devised such that firstly, ADMA was acylated by radio-labelled succinic acid, and followed by binding of the complex to anti-acyl ADMA-specific antibody coated on chip. Acylation condition of ADMA with radio-labelled succinic acid was established

  1. Development of RI protein chip system for measurement of ADMA as risk factor of liver disease, cardiovascular disease and diabetes

    International Nuclear Information System (INIS)

    ADMA (asymmetric dimethylarginine) is an endogenous competitive NOS (nitric oxide synthase) inhibitor. Elevation of ADMA level in body fluid is related to various diseases including diabetes mellitus, atherosclerosis, hypercholesterolemia, chronic heart failure, and hypertension. Our goal was to elucidate the role for ADMA and protein arginine methylation in the pathogenesis of diabetes and develop RI protein chip system for easy determination of ADMA levels in blood or tissues. As a result, ADMA regulated by protein arginine methylation, DDAH1, and NOS was demonstrated to play some role in the pathogenesis of diabetes mellitus, and arginine methylation of some proteins indicated their possible involvement in the change in ADMA levels. The concept of the RI protein chip system was devised such that firstly, ADMA was acylated by radio-labelled succinic acid, and followed by binding of the complex to anti-acyl ADMA-specific antibody coated on chip. Acylation condition of ADMA with radio-labelled succinic acid was established

  2. Asymmetric Dimethylarginine Is a Well Established Mediating Risk Factor for Cardiovascular Morbidity and Mortality—Should Patients with Elevated Levels Be Supplemented with Citrulline?

    Science.gov (United States)

    McCarty, Mark F.

    2016-01-01

    The arginine metabolite asymmetric dimethylarginine (ADMA) is a competitive inhibitor and uncoupler of endothelial nitric oxide synthase (eNOS), an enzyme that acts in multifarious ways to promote cardiovascular health. This phenomenon likely explains, at least in part, why elevated ADMA has been established as an independent risk factor for cardiovascular events, ventricular hypertrophy, and cardiovascular mortality. Fortunately, the suppressive impact of ADMA on eNOS activity can be offset by increasing intracellular arginine levels with supplemental citrulline. Although the long-term impact of supplemental citrulline on cardiovascular health in patients with elevated ADMA has not yet been studied, shorter-term clinical studies of citrulline administration demonstrate effects suggestive of increased NO synthesis, such as reductions in blood pressure and arterial stiffness, improved endothelium-dependent vasodilation, increased erection hardness, and increased ejection fractions in patients with heart failure. Supplemental citrulline could be a practical option for primary or secondary prevention of cardiovascular events and mortality, as it is inexpensive, has a mild flavor, and is well tolerated in doses (3–6 g daily) that can influence eNOS activity. Large and long-term clinical trials, targeting patients at high risk for cardiovascular events in whom ADMA is elevated, are needed to evaluate citrulline’s potential for aiding cardiovascular health. PMID:27417628

  3. Asymmetric Dimethylarginine Is a Well Established Mediating Risk Factor for Cardiovascular Morbidity and Mortality-Should Patients with Elevated Levels Be Supplemented with Citrulline?

    Science.gov (United States)

    McCarty, Mark F

    2016-07-08

    The arginine metabolite asymmetric dimethylarginine (ADMA) is a competitive inhibitor and uncoupler of endothelial nitric oxide synthase (eNOS), an enzyme that acts in multifarious ways to promote cardiovascular health. This phenomenon likely explains, at least in part, why elevated ADMA has been established as an independent risk factor for cardiovascular events, ventricular hypertrophy, and cardiovascular mortality. Fortunately, the suppressive impact of ADMA on eNOS activity can be offset by increasing intracellular arginine levels with supplemental citrulline. Although the long-term impact of supplemental citrulline on cardiovascular health in patients with elevated ADMA has not yet been studied, shorter-term clinical studies of citrulline administration demonstrate effects suggestive of increased NO synthesis, such as reductions in blood pressure and arterial stiffness, improved endothelium-dependent vasodilation, increased erection hardness, and increased ejection fractions in patients with heart failure. Supplemental citrulline could be a practical option for primary or secondary prevention of cardiovascular events and mortality, as it is inexpensive, has a mild flavor, and is well tolerated in doses (3-6 g daily) that can influence eNOS activity. Large and long-term clinical trials, targeting patients at high risk for cardiovascular events in whom ADMA is elevated, are needed to evaluate citrulline's potential for aiding cardiovascular health.

  4. Asymmetric Dimethylarginine Is a Well Established Mediating Risk Factor for Cardiovascular Morbidity and Mortality—Should Patients with Elevated Levels Be Supplemented with Citrulline?

    Directory of Open Access Journals (Sweden)

    Mark F. McCarty

    2016-07-01

    Full Text Available The arginine metabolite asymmetric dimethylarginine (ADMA is a competitive inhibitor and uncoupler of endothelial nitric oxide synthase (eNOS, an enzyme that acts in multifarious ways to promote cardiovascular health. This phenomenon likely explains, at least in part, why elevated ADMA has been established as an independent risk factor for cardiovascular events, ventricular hypertrophy, and cardiovascular mortality. Fortunately, the suppressive impact of ADMA on eNOS activity can be offset by increasing intracellular arginine levels with supplemental citrulline. Although the long-term impact of supplemental citrulline on cardiovascular health in patients with elevated ADMA has not yet been studied, shorter-term clinical studies of citrulline administration demonstrate effects suggestive of increased NO synthesis, such as reductions in blood pressure and arterial stiffness, improved endothelium-dependent vasodilation, increased erection hardness, and increased ejection fractions in patients with heart failure. Supplemental citrulline could be a practical option for primary or secondary prevention of cardiovascular events and mortality, as it is inexpensive, has a mild flavor, and is well tolerated in doses (3–6 g daily that can influence eNOS activity. Large and long-term clinical trials, targeting patients at high risk for cardiovascular events in whom ADMA is elevated, are needed to evaluate citrulline’s potential for aiding cardiovascular health.

  5. Correlation between Nitric oxide (NO & Asymmetric dimethylargininie (ADMA Hemoglobin Concentration in sickle cell patients

    Directory of Open Access Journals (Sweden)

    Kadkhodaei ElyaderaniM

    2010-01-01

    Full Text Available Background and objectives: The importance of Nitric oxide (NO andAsymmetric dimethylargininie (ADMA in pathophysiology of Sickle celldisease (SCD is being increasingly clarified. Since very few of the studieshave been conducted in the word and no study has been carried out in Iran,especially in Khuzestan province where is the main center of Sickle Celldisorder (SCD in Iran, We decided to conduct the present study.Material and Methods: EDTA anticoagulated plasma samples were obtainedfrom 35 healthy controls (Hb AA, 35 heterozygous (HB AS and 35homozygous (HB SS sickle cell anemia patients. Plasma concentration of NOwas measured by Colorimetric and Griess reaction and the concentration ofADMA by employing ELISA method. Then the results were analyzed by tstudenttest and OneWay ANOVA.Results: There is a positive significance correlation between Hemoglobin(Hb and NO in SS (r=0.703 and AS (r=0.366 groups. Also, a negativecorrelation between Hb and ADMA in SS (r=-0.786 and AS (r=-0.478groups is seen. No correlation is found between these parameters in AAgroup.Conclusion: The prevention of Hb concentration decrease and prescription ofNO donors and (or ADMA disintegrators can be helpful for improvingclinical signs of sickle cell patients.Key words: Nitric oxide (NO, Asymmetric dimethylargininie (ADMA,Sickle cell disease (SCD.

  6. Marker of endothelial dysfunction asymmetric dimethylarginine is elevated in HIV infection but not associated with sub-clinical atherosclerosis

    DEFF Research Database (Denmark)

    Haissman, Judith M; Haugaard, Anna K; Knudsen, Andreas;

    2016-01-01

    -sectional cohorts: Cohort A including 50 untreated and 50 anti-retroviral therapy (ART) treated HIV-infected individuals with previously assessed coagulation and platelet function, and Cohort B including 105 HIV-infected individuals on ART and 105 uninfected controls with previously assessed coronary artery calcium......BACKGROUND: Cardiovascular disease (CVD) contributes to excess morbidity and mortality in HIV infection, and endothelial dysfunction may contribute to this pattern. We aimed to determine endothelial function in treated and untreated HIV-infected individuals and investigate potential associations...... with viral replication, immune activation, coagulation, platelet function, and subclinical atherosclerosis. METHODS: Asymmetric dimethylarginine (ADMA, marker of endothelial dysfunction) and soluble CD14 (sCD14, marker of monocyte activation) were measured in plasma from two previously established cross...

  7. Combined intraperitoneal and intrathecal etanercept reduces increased brain tumor necrosis factor-alpha and asymmetric dimethylarginine levels and rescues spatial deficits in young rats after bile duct ligation

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    Jiunn-Ming Sheen

    2016-06-01

    Full Text Available Background: Rats subjected to bile duct ligation (BDL exhibit increased systemic oxidative stress and brain dysfunction characteristic of hepatic encephalopathy, including fatigue, neurotransmitter alterations, cognitive and motor impairment, and brain inflammation. The levels of tumor necrosis factor-alpha (TNF-α and asymmetric dimethylarginine (ADMA are both increased in plasma and brain in encephalopathy induced by chronic liver failure. This study first determined the temporal profiles of TNF-α and ADMA in the plasma, brain cortex, and hippocampus in young BDL rats. Next, we examined whether etanercept was beneficial in preventing brain damage.Methods: Young rats underwent sham ligation or BDL at day 17 ± 1 for 4 weeks. Treatment group rats were administered etanercept (10 mg/kg intraperitoneally (IP three times per week with or without etanercept (100 µg intrathecally (IT three times in total.Results: We found increased plasma TNF-α, soluble tumor necrosis factor receptor 1, soluble tumor necrosis factor receptor 2, and ADMA levels, increased cortical TNF-α mRNA and protein and ADMA, and hippocampal TNF-α mRNA and protein, and spatial defects in young BDL rats. The increase in cortex TNF-α mRNA and ADMA were reduced by IP etanercept or combined IP and IT etanercept. Dually IP/IT etanercept administration reduced the increased cortical and hippocampal TNF-α mRNA and protein level as well as spatial deficits.Conclusions: We conclude that combined intraperitoneal and intrathecal etanercept reduce increased brain TNF-α and ADMA levels and rescues spatial deficits in young rats after BDL.

  8. Asymmetric dimethylarginine and neonatal-related diseases%不对称二甲基精氨酸和新生儿相关疾病的关系

    Institute of Scientific and Technical Information of China (English)

    黄惠娟; 陈玮琪

    2010-01-01

    Asymmetric dimethylarginine(ADMA) is an endogenous inhibitor of nitric oxide synthases(NOS),which is a risk marker of cardiovascular endothelial dysfunction.Recent studies found that ADMA was a predictor not only for acute cardiovascular disease,but also for critical illness and mortality.Studies have found that exogenous ADMA altered lung function and induced apoptosis in animal experiments and vitro experiments.The levels of plasma ADMA significantly increased in children with hypoxia,PPHN,brain damage,and preterm infants who required mechanical ventilation.ADMA could be a independent risk factor to predict neonatal complications and death.%不对称二甲基精氨酸(ADMA)是一氧化氮合酶(NOS)的内源性竞争性抑制剂,是血管内皮功能不全的危险因子.近年来研究发现,ADMA不仅是预测急性心血管疾病的危险因子,而且是一种新的预测危重疾病及死亡的危险因子.在动物实验及体外实验发现,外源性ADMA能明显改变肺功能,诱导细胞凋亡.在缺氧、PPHN、需机械通气的早产儿、脑损伤中,ADMA水平均升高.ADMA可能是预测新生儿严重并发症和死亡的独立危险因子.

  9. Correlation between Nitric oxide (NO) & Asymmetric dimethylargininie (ADMA) Hemoglobin Concentration in sickle cell patients

    OpenAIRE

    Kadkhodaei ElyaderaniM; Rostami M; Keikhaie B; PedramM

    2010-01-01

    Background and objectives: The importance of Nitric oxide (NO) andAsymmetric dimethylargininie (ADMA) in pathophysiology of Sickle celldisease (SCD) is being increasingly clarified. Since very few of the studieshave been conducted in the word and no study has been carried out in Iran,especially in Khuzestan province where is the main center of Sickle Celldisorder (SCD) in Iran, We decided to conduct the present study.Material and Methods: EDTA anticoagulated plasma samples were obtainedfrom 3...

  10. Value of plasma ADMA in predicting cardiac structure and function of patients with chronic kidney diseases

    Institute of Scientific and Technical Information of China (English)

    叶建华

    2012-01-01

    Objective To explore the predicting value of plasma asymmetric dimethylarginine (ADMA) in cardiac structure and function of patients with chronic kidney diseases(CKD). Methods A total of 100 CKD patients were enrolled in this cross-sectional study. According to staging of the

  11. The Analysis of Asymetric Dimethylarginine and Homocysteine in Patients with Chronic Kidney Disease

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    Tetty Hendrawati

    2009-08-01

    Full Text Available BACKGROUND: Asymmetric dimethylarginine (ADMA is a competitive inhibitor of nitric oxide synthase (NOS. ADMA reduces NO synthesis when its concentration elevates. ADMA is a novel risk factor for cardiovascular disease. Plasma ADMA accumulates in patients with endstage renal disease, due to reduced renal clearance. Hyperhomocysteinemia is often found in patients with chronic kidney disease (CKD. Homocysteine may cause ADMA to accumulate; however, the mechanism by which ADMA level elevates in hyperhomocysteinemia is still unclear. Objective of this study was to analyze the concentrations of homocysteine and ADMA and to assess the correlation between homocysteine and ADMA concentrations with the severity of chronic kidney disease. METHODS: This was a cross-sectional study on 75 patients with CKD, comprising men and women aged 40-70 years. Assessments were done on the concentrations of creatinine, homocysteine, ADMA, fasting blood glucose, cholesterol HDL and triglyceride. RESULTS: In later stage of CKD there was significantly higher tHcy concentration as compared with the earlier stage of CKD (p=0.0000. In CKD stage 2 to 4 there was a tendency for ADMA concentration to increase to a significant average (p=0.210, but ADMA concentration was lower at stage 5. There was increased ADMA along with increased tHcy concentration of around 20μ mol/L, and this then decreased. The inverse correlation between tHcy and ADMA concentrations started to appear in CKD stage 4, but this correlation was statistically insignificant (r2=0.19; p=0.499. CONCLUSIONS: This study showed there was a correlation between homocysteine and ADMA concentrations in patients with CKD stage 2 to 5, although statistically not significant. KEYWORDS: asymmetric dimethylarginine, homocysteine, chronic kidney disease.

  12. Asymmetric Dimethyarginine as Marker and Mediator in Ischemic Stroke

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    Karin Weissenborn

    2012-11-01

    Full Text Available Asymmetric dimethylarginine (ADMA, an endogenous nitric oxide synthase (NOS inhibitor, is known as mediator of endothelial cell dysfunction and atherosclerosis. Circulating ADMA levels are correlated with cardiovascular risk factors such as hypercholesterolemia, arterial hypertension, diabetes mellitus, hyperhomocysteinemia, age and smoking. Accordingly, clinical studies found evidence that increased ADMA levels are associated with a higher risk of cerebrovascular events. After the acute event of ischemic stroke, levels of ADMA and its analog symmetric dimethylarginine (SDMA are elevated through augmentation of protein methylation and oxidative stress. Furthermore, cleavage of ADMA through dimethylarginine dimethylaminohydrolases (DDAHs is reduced. This increase of dimethylarginines might be predictive for adverse clinical outcome. However, the definite role of ADMA after acute ischemic stroke still needs to be clarified. On the one hand, ADMA might contribute to brain injury by reduction of cerebral blood flow. On the other hand, ADMA might be involved in NOS-induced oxidative stress and excitotoxic neuronal death. In the present review, we highlight the current knowledge from clinical and experimental studies on ADMA and its role for stroke risk and ischemic brain injury in the hyperacute stage after stroke. Finally, further studies are warranted to unravel the relevance of the close association of dimethylarginines with stroke.

  13. Does the ADMA/DDAH/NO pathway modulate early regression of left ventricular hypertrophy with esmolol?

    Science.gov (United States)

    Quintana-Villamandos, Begoña; Delgado-Baeza, Emilio

    2016-02-01

    Hypertensive left ventricular hypertrophy (LVH) is a maladaptive response to chronic pressure overload and a strong independent risk factor for cardiovascular disease. Regression of LVH is associated with improved prognosis. Regression of LVH with antihypertensive therapy (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers, and diuretics) has been reported, although only after long-term treatment. Asymmetrical dimethylarginine (ADMA), the most potent endogenous NO synthase inhibitor, is emerging as an important cardiovascular risk factor in patients with arterial hypertension and LVH, and dimethylarginine dimethylaminohydrolase (DDAH) is the mechanism that most frequently leads to accumulation of ADMA (plasma ADMA is cleared in small part by renal excretion, although the bulk of ADMA is degraded by DDAH). Left ventricular mass is strongly modulated by the NO system. As an important inhibitor of the bioavailability of NO, ADMA is an underlying mechanism of LVH. Beta-blockers can induce regression of LVH and reduced plasma ADMA levels. Oxidative stress is increased in patients with LVH, and this in turn increases generation of ADMA. In a previous preclinical study of spontaneously hypertensive rats, we found that short-term treatment (48 h) with esmolol reverses early LVH, increases the bioavailability of NO, and improves antioxidant status in plasma. Therefore, we propose that the ADMA/DDAH/NO pathway could modulate early regression of LVH with esmolol. PMID:26826640

  14. Effects of ADMA upon gene expression: an insight into the pathophysiological significance of raised plasma ADMA.

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    Caroline L Smith

    2005-10-01

    Full Text Available BACKGROUND: Asymmetric dimethylarginine (ADMA is a naturally occurring inhibitor of nitric oxide synthesis that accumulates in a wide range of diseases associated with endothelial dysfunction and enhanced atherosclerosis. Clinical studies implicate plasma ADMA as a major novel cardiovascular risk factor, but the mechanisms by which low concentrations of ADMA produce adverse effects on the cardiovascular system are unclear. METHODS AND FINDINGS: We treated human coronary artery endothelial cells with pathophysiological concentrations of ADMA and assessed the effects on gene expression using U133A GeneChips (Affymetrix. Changes in several genes, including bone morphogenetic protein 2 inducible kinase (BMP2K, SMA-related protein 5 (Smad5, bone morphogenetic protein receptor 1A, and protein arginine methyltransferase 3 (PRMT3; also known as HRMT1L3, were confirmed by Northern blotting, quantitative PCR, and in some instances Western blotting analysis to detect changes in protein expression. To determine whether these changes also occurred in vivo, tissue from gene deletion mice with raised ADMA levels was examined. More than 50 genes were significantly altered in endothelial cells after treatment with pathophysiological concentrations of ADMA (2 microM. We detected specific patterns of changes that identify pathways involved in processes relevant to cardiovascular risk and pulmonary hypertension. Changes in BMP2K and PRMT3 were confirmed at mRNA and protein levels, in vitro and in vivo. CONCLUSION: Pathophysiological concentrations of ADMA are sufficient to elicit significant changes in coronary artery endothelial cell gene expression. Changes in bone morphogenetic protein signalling, and in enzymes involved in arginine methylation, may be particularly relevant to understanding the pathophysiological significance of raised ADMA levels. This study identifies the mechanisms by which increased ADMA may contribute to common cardiovascular diseases and

  15. Pilot study of the association of the DDAH2 -449G polymorphism with asymmetric dimethylarginine and hemodynamic shock in pediatric sepsis.

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    Scott L Weiss

    Full Text Available BACKGROUND: Genetic variability in the regulation of the nitric oxide (NO pathway may influence hemodynamic changes in pediatric sepsis. We sought to determine whether functional polymorphisms in DDAH2, which metabolizes the NO synthase inhibitor asymmetric dimethylarginine (ADMA, are associated with susceptibility to sepsis, plasma ADMA, distinct hemodynamic states, and vasopressor requirements in pediatric septic shock. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective study, blood and buccal swabs were obtained from 82 patients ≤ 18 years (29 with severe sepsis/septic shock plus 27 febrile and 26 healthy controls. Plasma ADMA was measured using tandem mass spectrometry. DDAH2 gene was partially sequenced to determine the -871 6g/7 g insertion/deletion and -449G/C single nucleotide polymorphisms. Shock type ("warm" versus "cold" was characterized by clinical assessment. The -871 7g allele was more common in septic (17% then febrile (4% and healthy (8% patients, though this was not significant after controlling for sex and race (p = 0.96. ADMA did not differ between -871 6g/7 g genotypes. While genotype frequencies also did not vary between groups for the -449G/C SNP (p = 0.75, septic patients with at least one -449G allele had lower ADMA (median, IQR 0.36, 0.30-0.41 µmol/L than patients with the -449CC genotype (0.55, 0.49-0.64 µmol/L, p = 0.008 and exhibited a higher incidence of "cold" shock (45% versus 0%, p = 0.01. However, after controlling for race, the association with shock type became non-significant (p = 0.32. Neither polymorphism was associated with inotrope score or vasoactive infusion duration. CONCLUSIONS/SIGNIFICANCE: The -449G polymorphism in the DDAH2 gene was associated with both low plasma ADMA and an increased likelihood of presenting with "cold" shock in pediatric sepsis, but not with vasopressor requirement. Race, however, was an important confounder. These results support and justify the need for larger studies in

  16. High tea and vegetable consumption is associated with low ADMA generation in older healthy subjects.

    Science.gov (United States)

    Goralczyk, Tadeusz; Tisonczyk, Joanna; Fijorek, Kamil; Undas, Anetta

    2012-08-01

    Asymmetric dimethylarginine (ADMA) has been recognized as a marker of cardiovascular risk. We sought to investigate whether consumption of tea, coffee, fruit or vegetables is associated with ADMA. In 148 consecutive apparently healthy subjects (104 men and 44 women aged 40 to 70), daily tea, coffee, fruit and vegetable consumption was ascertained by questionnaire. Plasma ADMA, symmetric dimethylarginine (SDMA), and l-arginine levels were measured by high-performance liquid chromatography. Median tea and coffee consumption was 2 cups/d, while vegetable and fruit intake was 152 (120-179)g/d and 120 (108-134)g/d, respectively. Median plasma ADMA, SDMA and arginine were 0.47 (0.43-0.53)μmol/L, 0.59 (0.54-0.66)μmol/L and 86 (68-101)μmol/L, respectively. ADMA correlated inversely with tea (r = -0.70, P vegetable consumption (r = -0.50, P fruit consumption was found. ADMA correlated positively with coffee intake (r = 0.37, P < .0001), although these associations were less potent after adjustment for dietary factors. Higher tea and vegetable intake is associated with lower plasma ADMA levels in healthy middle-aged subjects.

  17. Effect of silibinin on endothelial dysfunction and ADMA levels in obese diabetic mice

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    Siarkos Ilias

    2011-07-01

    Full Text Available Abstract Background Cardiovascular diseases (CVD in diabetic patients have endothelial dysfunction as a key pathogenetic event. Asymmetric dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase (NOS, plays a pivotal role in endothelial dysfunction. Different natural polyphenols have been shown to preserve endothelial function and prevent CVD. In this study, we assessed the effect of silibinin, a widely used flavonolignan from milk thistle, on ADMA levels and endothelial dysfunction in db/db mice. Methods Eight-week-old db/db mice were administrated a 20 mg/Kg i.p. daily dose of silibinin (n = 6 or vehicle (n = 6 for four weeks. Heterozygous lean db/m mice served as control. Plasma, aorta and liver ADMA levels were determined by ELISA. Vascular reactivity to phenilephrine (PE, acetylcholine (ACh, sodium nitroprusside (SNP and ADMA was assessed in isolated aortic segments, in wire myograph. Results Plasma and aorta ADMA levels were higher in db/db than in control lean mice. Silibinin administration markedly decreased plasma ADMA; consistently, aorta ADMA was reduced in silibinin-treated animals. Plasma and aorta ADMA levels exhibited a positive correlation, whereas liver ADMA was inversely correlated with both plasma and aorta ADMA concentrations. Endothelium-(NO-dependent vasodilatation to ACh was impaired in db/db mice and was restored in the silibinin group, in accordance with the observed reduction of plasma and vascular levels of ADMA. Endothelium-independent vasodilatation to SNP was not modified by silibinin administration; contractile tone induced in isolated aorta from db/db mice by challenging with exogenous ADMA was not affected by the treatment. Conclusions Silibinin markedly improves endothelial dysfunction in db/db mice by reducing circulating and vascular ADMA levels. Clinical studies are warranted to assess the efficacy of silibinin for cardiovascular protection.

  18. Sequence variation in DDAH1 and DDAH2 genes is strongly and additively associated with serum ADMA concentrations in individuals with type 2 diabetes.

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    Sotoodeh Abhary

    Full Text Available BACKGROUND: Asymmetric dimethylarginine (ADMA, present in human serum, is an endogenous inhibitor of nitric oxide synthase and contributes to vascular disease. Dimethylarginine dimethylaminohydrolase (DDAH is an ADMA degrading enzyme that has two isoforms: DDAHI and DDAHII. We sought to determine whether serum ADMA levels in type 2 diabetes are influenced by common polymorphisms in the DDAH1 and DDAH2 genes. METHODOLOGY/PRINCIPAL FINDINGS: Relevant clinical parameters were measured and peripheral whole blood obtained for serum and genetic analysis on 343 participants with type 2 diabetes. Serum ADMA concentrations were determined by mass spectroscopy. Twenty six tag SNPs in the DDAH1 and 10 in the DDAH2 gene were genotyped in all subjects and tested for association with serum ADMA levels. Several SNPs and haplotypes in the DDAH genes were strongly associated with ADMA levels. Most significantly in the DDAH1 gene, rs669173 (p = 2.96x10(-7, rs7521189 (p = 6.40x10(-7, rs2474123 (p = 0.00082 and rs13373844 (p = 0.00027, and in the DDAH2 gene, rs3131383 (p = 0.0029 and the TGCCCAGGAG haplotype (p = 0.0012 were significantly associated with ADMA levels. Sub-analysis by diabetic retinopathy (DR status revealed these variants were associated with ADMA levels predominantly in participants without DR. Combined analysis of the most strongly associated SNPs in DDAH1 (rs669173 and DDAH2 (rs3131383 revealed an additive effect (p = 1.37x10(-8 on ADMA levels. CONCLUSIONS/SIGNIFICANCE: Genetic variation in the DDAH1 and 2 genes is significantly associated with serum ADMA levels. Further studies are required to determine the pathophysiological significance of elevated serum ADMA in type 2 diabetes and to better understand how DDAH gene variation influences ADMA levels.

  19. Effects of ADMA on gene expression and metabolism in serum-starved LoVo cells.

    Science.gov (United States)

    Zheng, Ningning; Wang, Ke; He, Jiaojiao; Qiu, Yunping; Xie, Guoxiang; Su, Mingming; Jia, Wei; Li, Houkai

    2016-05-16

    Serum starvation is a typical way for inducing tumor cell apoptosis and stress. Asymmetric dimethylarginine (ADMA) is an endogenous metabolite. Our previous study reveals the plasma ADMA level is elevated in colon cancer patients, which can attenuate serum starvation-induced apoptosis in LoVo cells. In current study, we evaluated the effects of ADMA on gene expression and metabolism in serum-starved LoVo cells with gene microarray and metabolomic approaches. Our results indicated that 96 h serum starvation induced comprehensive alterations at transcriptional level, and most of them were restored by ADMA. The main signaling pathways induced by serum starvation included cancers-related pathways, pathways in cell death, apoptosis, and cell cycle etc. Meanwhile, the metabolomic data showed serum-starved cells were clearly separated with control cells, but not with ADMA-treated cells in PCA model. The identified differential metabolites indicated serum starvation significantly suppressed TCA cycle, altered glucose and fatty acids metabolism, as well as nucleic acids metabolism. However, very few differential metabolites were identified between ADMA and serum-starved cells. In summary, our current results indicated serum starvation profoundly altered the gene expression and metabolism of LoVo cells, whereas ADMA could restore most of the changes at transcriptional level, but not at metabolic level.

  20. Asymmetric dimethylarginine inhibits HSP90 activity in Pulmonary Arterial Endothelial Cells: Role of Mitochondrial Dysfunction

    OpenAIRE

    Sud, Neetu; Wells, Sandra M.; Wiseman, Dean A.; Wilham, Jason; Black, Stephen M.

    2008-01-01

    Increased ADMA levels have been implicated in the pathogenesis of a number of conditions affecting the cardiovascular system. However, the mechanism(s) by which ADMA exerts its effect has not been adequately elucidated. Thus, the purpose of this study was to determine the effect of increased ADMA on nitric oxide (NO) signaling and to begin to elucidate the mechanism by which ADMA acts. Our initial data demonstrated that that ADMA increased NOS uncoupling both in recombinant human endothelial ...

  1. N-Acetylcysteine Prevents Hypertension via Regulation of the ADMA-DDAH Pathway in Young Spontaneously Hypertensive Rats

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    Nai-Chia Fan

    2013-01-01

    Full Text Available Asymmetric dimethylarginine (ADMA reduces nitric oxide (NO, thus causing hypertension. ADMA is metabolized by dimethylarginine dimethylaminohydrolase (DDAH, which can be inhibited by oxidative stress. N-Acetylcysteine (NAC, an antioxidant, can facilitate glutathione (GSH synthesis. We aimed to determine whether NAC can prevent hypertension by regulating the ADMA-DDAH pathway in spontaneously hypertensive rats (SHR. Rats aged 4 weeks were assigned into 3 groups (n=8/group: control Wistar Kyoto rats (WKY, SHR, and SHR receiving 2% NAC in drinking water. All rats were sacrificed at 12 weeks of age. SHR had higher blood pressure than WKY, whereas NAC-treated animals did not. SHR had elevated plasma ADMA levels, which was prevented by NAC therapy. SHR had lower renal DDAH activity than WKY, whereas NAC-treated animals did not. Renal superoxide production was higher in SHR than in WKY, whereas NAC therapy prevented it. NAC therapy was also associated with higher GSH-to-oxidized GSH ratio in SHR kidneys. Moreover, NAC reduced oxidative stress damage in SHR. The observed antihypertensive effects of NAC in young SHR might be due to restoration of DDAH activity to reduce ADMA, leading to attenuation of oxidative stress. Our findings highlight the impact of NAC on the development of hypertension by regulating ADMA-DDAH pathway.

  2. The separation and analysis of symmetric and asymmetric dimethylarginine and other hydrophilic isobaric compounds using aqueous normal phase chromatography.

    Science.gov (United States)

    Pesek, Joseph J; Matyksa, Maria T; Modereger, Brent; Hasbun, Alejandra; Phan, Vy T; Mehr, Zahra; Guzman, Mariano; Watanable, Seiichiro

    2016-04-01

    Two biologically important compounds with clinical relevance, asymmetric dimethylarginine and symmetric dimethylarginine, are analyzed using aqueous normal phase chromatography on silica hydride-based columns. Two different stationary phases were tested, a commercially available Diamond Hydride™ and a 2-acrylamido-2-methylpropane sulfonic acid experimental column. Two types of analytical protocols were investigated: analysis of the compounds when separation was achieved and analysis of the compounds with partial chromatographic separation. Urine samples from tuberculosis patients were tested for levels of asymmetric and symmetric dimethylarginine. The mass spectrometric technique of in-source fragmentation that can provide data similar to a tandem mass analyzer was evaluated as a means of identification and quantitation of the two compounds when complete separation is not achieved. This same protocol was also evaluated for two other isobaric compounds, glucose-1 and glucose-6 phohsphate, and leucine and isoleucine.

  3. Serum and cerebrospinal fluid concentrations of homoarginine, arginine, asymmetric and symmetric dimethylarginine, nitrite and nitrate in patients with multiple sclerosis and neuromyelitis optica.

    Science.gov (United States)

    Haghikia, Aiden; Kayacelebi, Arslan Arinc; Beckmann, Bibiana; Hanff, Erik; Gold, Ralf; Haghikia, Arash; Tsikas, Dimitrios

    2015-09-01

    The pathogenic hallmarks of multiple sclerosis (MS) and neuromyelitis optica (NMO) are cellular and humoral inflammatory infiltrates and subsequent demyelination, or astrocytic cell death in NMO, respectively. These processes are accompanied by disruption of the blood-brain barrier as regularly observed by gadolinium enhancement on magnetic resonance imaging. The role of the L-arginine/nitric oxide (NO) pathway in the pathophysiology of neuroinflammatory diseases, such as MS and NMO, remains unclear. In the present study, we measured the concentrations of the nitric oxide (NO) metabolites nitrate and nitrite, the endogenous substrates of NO synthase (NOS) L-arginine (Arg) and L-homoarginine (hArg), and asymmetric dimethylarginine (ADMA), the endogenous inhibitor of NOS activity, in the serum and cerebrospinal fluid (CSF) of patients with MS, NMO or other neurologic diseases (OND). MS (551 ± 23 nM, P = 0.004) and NMO (608 ± 51 nM, P = 0.006) patients have higher ADMA concentrations in serum than healthy controls (HC; 430 ± 24 nM). For MS, this finding was confirmed in CSF (685 ± 100 nM in relapsing-remitting multiple sclerosis, RRMS; 597 ± 51 nM in secondary progressive multiple sclerosis, SPMS) compared with OND (514 ± 37 nM; P = 0.003). Serum concentrations of Arg (61.1 ± 9.7 vs. 63.6 ± 4.9 µM, P = 0.760), hArg (2.62 ± 0.26 vs. 2.52 ± 0.23 µM, P = 0.891), nitrate (38.1 ± 2.2 vs. 38.1 ± 3.0 µM) and nitrite (1.37 ± 0.09 vs. 1.55 ± 0.03 µM) did not differ between MS and OND. Also, CSF concentrations of hArg (0.685 ± 0.100 µM in RRMS, 0.597 ± 0.051 µM in SPMS, 0.514 ± 0.037 µM in OND), nitrate (11.3 ± 0.6 vs. 10.5 ± 0.3 µM) and nitrite (2.84 ± 0.32 vs. 2.41 ± 0.11 µM) did not differ between the groups. In NMO patients, however, serum Arg (117 ± 11 vs. 64 ± 4.9 μM, P = 0.004), nitrate (29 ± 2.1 vs. 38 ± 3 μM, P = 0.03), and nitrite (1.09 ± 0.02 vs. 1.55 ± 0.033 µM, P < 0.0001) were significantly different as compared to OND

  4. In vivo evidence that Agxt2 can regulate plasma levels of dimethylarginines in mice.

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    Kittel, Anja; Maas, Renke; König, Jörg; Mieth, Maren; Weiss, Norbert; Jarzebska, Natalia; Hohenstein, Bernd; Martens-Lobenhoffer, Jens; Bode-Böger, Stefanie M; Rodionov, Roman N

    2013-01-01

    Elevated plasma concentrations of the asymmetric (ADMA) and symmetric (SDMA) dimethylarginine have repeatedly been linked to adverse cardiovascular clinical outcomes. Both dimethylarginines can be degraded by alanine-glyoxylate aminotransferase 2 (Agxt2), which is also the key enzyme responsible for the degradation of endogenously formed β-aminoisobutyrate (BAIB). In the present study we wanted to investigate the effect of BAIB on Agxt2 expression and Agxt2-mediated metabolism of dimethylarginines. We infused BAIB or saline intraperitoneally for 7days in C57/BL6 mice via minipumps. Expression of Agxt2 was determined in liver and kidney. The concentrations of BAIB, dimethylarginines and the Agxt2-specific ADMA metabolite α-keto-δ-(N(G),N(G)-dimethylguanidino)valeric acid (DMGV) was determined by LC-MS/MS in plasma and urine. As compared to controls systemic administration of BAIB increased plasma and urine BAIB levels by a factor of 26.5 (p<0.001) and 25.8 (p<0.01), respectively. BAIB infusion resulted in an increase of the plasma ADMA and SDMA concentrations of 27% and 31%, respectively, (both p<0.05) and a 24% decrease of plasma DMGV levels (p<0.05), while expression of Agxt2 was not different. Our data demonstrate that BAIB can inhibit Agxt2-mediated metabolism of dimethylarginines and show for the first time that endogenous Agxt2 is involved in the regulation of systemic ADMA, SDMA and DMGV levels. The effect of BAIB excess on endogenous dimethylarginine levels may have direct clinical implications for humans with the relatively common genetic trait of hyper-β-aminoisobutyric aciduria.

  5. Asymmetric Dimethylarginine and Pro-B-Type Natriuretic Peptide Levels in Patients With Carbon Monoxide Poisoning

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    Murat Eroglu

    2013-04-01

    CONCLUSIONS: Despite COHB level decreased, ADMA increased after oxygen therapy in patients with CO poisoning. We think that CO poisoning induced oxidative stress may cause increased ADMA levels. Further studies are needed to evaluate the importance of ADMA in CO poisoning. [Dis Mol Med 2013; 1(2.000: 21-25

  6. ADMA/SDMA in Elderly Subjects with Asymptomatic Carotid Atherosclerosis: Values and Site-Specific Association

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    Graziano Riccioni

    2014-04-01

    Full Text Available Asymmetric dimethylarginine (ADMA is an endogenous nitric oxide synthase (NOS inhibitor known as a mediator of endothelial dysfunction and atherosclerosis. Circulating ADMA levels are correlated with cardiovascular risk factors such as hypercholesterolemia, arterial hypertension, diabetes mellitus, hyperhomocysteinemia, age and smoking. We assessed the relationship between ADMA values and site-specific association of asymptomatic carotid atherosclerosis (intima-media thickness (CIMT and plaque in elderly subjects. One hundred and eighty subjects underwent a complete history and physical examination, determination of serum chemistries and ADMA levels, and carotid ultrasound investigation (CUI. All subjects had no acute or chronic symptoms of carotid atherosclerosis. Statistical analyses showed that high plasma levels of ADMA/SDMA were positively correlated to carotid atherosclerosis (CIMT and plaque (p < 0.001, with significant site-specific association. Total cholesterol, low density lipoprotein cholesterol, triglycerides and C-reactive protein plasma concentrations were significantly associated with asymptomatic carotid atherosclerosis (p < 0.001. High serum concentrations of ADMA and SDMA were associated with carotid atherosclerotic lesions as measured by CIMT ad plaque and may represent a new marker of asymptomatic carotid atherosclerosis in elderly subjects.

  7. Inhibitors of the Hydrolytic Enzyme Dimethylarginine Dimethylaminohydrolase (DDAH): Discovery, Synthesis and Development.

    Science.gov (United States)

    Murphy, Rhys B; Tommasi, Sara; Lewis, Benjamin C; Mangoni, Arduino A

    2016-01-01

    Dimethylarginine dimethylaminohydrolase (DDAH) is a highly conserved hydrolytic enzyme found in numerous species, including bacteria, rodents, and humans. In humans, the DDAH-1 isoform is known to metabolize endogenous asymmetric dimethylarginine (ADMA) and monomethyl arginine (l-NMMA), with ADMA proposed to be a putative marker of cardiovascular disease. Current literature reports identify the DDAH family of enzymes as a potential therapeutic target in the regulation of nitric oxide (NO) production, mediated via its biochemical interaction with the nitric oxide synthase (NOS) family of enzymes. Increased DDAH expression and NO production have been linked to multiple pathological conditions, specifically, cancer, neurodegenerative disorders, and septic shock. As such, the discovery, chemical synthesis, and development of DDAH inhibitors as potential drug candidates represent a growing field of interest. This review article summarizes the current knowledge on DDAH inhibition and the derived pharmacokinetic parameters of the main DDAH inhibitors reported in the literature. Furthermore, current methods of development and chemical synthetic pathways are discussed. PMID:27187323

  8. Inhibitors of the Hydrolytic Enzyme Dimethylarginine Dimethylaminohydrolase (DDAH): Discovery, Synthesis and Development.

    Science.gov (United States)

    Murphy, Rhys B; Tommasi, Sara; Lewis, Benjamin C; Mangoni, Arduino A

    2016-01-01

    Dimethylarginine dimethylaminohydrolase (DDAH) is a highly conserved hydrolytic enzyme found in numerous species, including bacteria, rodents, and humans. In humans, the DDAH-1 isoform is known to metabolize endogenous asymmetric dimethylarginine (ADMA) and monomethyl arginine (l-NMMA), with ADMA proposed to be a putative marker of cardiovascular disease. Current literature reports identify the DDAH family of enzymes as a potential therapeutic target in the regulation of nitric oxide (NO) production, mediated via its biochemical interaction with the nitric oxide synthase (NOS) family of enzymes. Increased DDAH expression and NO production have been linked to multiple pathological conditions, specifically, cancer, neurodegenerative disorders, and septic shock. As such, the discovery, chemical synthesis, and development of DDAH inhibitors as potential drug candidates represent a growing field of interest. This review article summarizes the current knowledge on DDAH inhibition and the derived pharmacokinetic parameters of the main DDAH inhibitors reported in the literature. Furthermore, current methods of development and chemical synthetic pathways are discussed.

  9. The association of adipose-derived dimethylarginine dimethylaminohydrolase-2 with insulin sensitivity in experimental type 2 diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    Jie Zheng; Kuansong Wang; Ping Jin; Changsheng Dong; Qiong Yuan; Yuanjian Li; Zhichun Yang

    2013-01-01

    Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS),which can be hydrolyzed by dimethylarginine-dimethylaminohydrolase (DDAH).It has been reported that adipocytes can produce DDAH/ADMA,but its role remains unknown.In the present study,we examined the effects of adipocyte-derived DDAH/ADMA on insulin sensitivity using animal and cell models.Results showed that in adipose tissue of high fat diet-fed diabetic rats,as well as in high glucose (25 mM) plus insulin (100nM)-treated 3T3-L1 adipocytes,expression levels of insulin receptor substance-1 (IRS-1),glucose transporter-4 (GLUT-4),and DDAH isoform-2 (DDAH-2) were down-regulated compared with control,although DDAH-1 expression showed no significant changes.We also observed that nitric oxide bioavailability,DDAH and NOS activities were subsequently decreased,while the local ADMA content was elevated in diabetic adipose tissue.Transfection of human DDAH-2 gene into high glucose-and insulin-treated 3T3-L1 adipocytes significantly ameliorated DDAH activity,reduced ADMA contents,and up-regulated the mRNA expression levels of IRS-1 and GLUT-4.These findings suggested that in the development of type 2 diabetes mellitus,local DDAH-2 in adipocytes might play an important role in regulating insulin sensitivity.

  10. Serum Asymmetric Dimethylarginine, and Adiponectin as Predictors of Atherosclerotic Risk among Obese Egyptian Children

    Directory of Open Access Journals (Sweden)

    Enas R. Abdel Hameed

    2014-06-01

    CONCLUSIONS: Our results revealed that ADMA, Adiponectin and lipid profile can be considered as predictive biomarkers in prediction and prevention of atherosclerotic risk in the future among overweight and obese Egyptian children.

  11. Asymmetric dimethylarginine and lipid peroxidation products in early autosomal dominant polycystic kidney disease

    DEFF Research Database (Denmark)

    Wang, Dan; Strandgaard, S.; Borresen, M.L.;

    2008-01-01

    of nitric oxide synthase and the lipid peroxidation product 13-hydroxyoctadecadienoic acid (HODE) as a marker of oxidative stress in patients with early ADPKD. Study Design: Cross-sectional study. Setting & Participants: Patients with early ADPKD (n = 27) and age-matched volunteers (n = 30) from a single...... academic medical center. Factor: Patients with ADPKD versus controls. Outcomes & Measurement: Plasma (P) levels, urinary (U) excretion, and urinary clearance (C) of ADMA and HODE. Because of multiple comparisons, P for significance is considered less than 0.0167. Results: Patients with ADPKD had......-sectional nature of study, and limited number of markers of oxidative stress. Conclusions: P-ADMA and P-HODE levels are increased in patients with early ADPKD. Increased P-ADMA level is related to decreased CADMA and is accompanied by oxidative stress. Am J Kidney Dis 51:184-191. (c) 2008 by the National Kidney...

  12. Asymmetric dimethylarginine, oxidative stress, and vascular nitric oxide synthase in essential hypertension

    DEFF Research Database (Denmark)

    Wang, Dan; Strandgaard, Svend; Iversen, Jens;

    2009-01-01

    We reported impaired endothelium-derived relaxation factor/nitric oxide (EDRF/NO) responses and constitutive nitric oxide synthase (cNOS) activity in subcutaneous vessels dissected from patients with essential hypertension (n = 9) compared with normal controls (n = 10). We now test the hypothesis...... and hypertensive subjects, the individual values for plasma levels of ADMA and HODE were both significantly (P blood pressure. In conclusion, elevated levels of ADMA and oxidative stress in a group of hypertensive...... patients could contribute to the associated microvascular endothelial dysfunction and elevated blood pressure....

  13. The effect of taurine on the relationship between NO, ADMA and homocysteine in endotoxin-mediated inflammation in HUVEC cultures.

    Science.gov (United States)

    Pasaoglu, Ozge Tugce; Turkozkan, Nurten; Ark, Mustafa; Polat, Belgin; Agilli, Mehmet; Yaman, Halil

    2014-10-01

    The aim of our study was to investigate the effect of taurine on the relationship between nitric oxide (NO), asymmetric dimethylarginine (ADMA) and homocysteine (Hcy) in endotoxin-induced human umblical vein endothelial cell (HUVEC) cultures. For this reason, four groups were formed (n=12). Control group consists of HUVEC cultures without any treatment. Lipopolysaccharide (LPS) and LPS+taurine groups were treated with 10 μg/mL endotoxin, 5 μg/mL taurine and endotoxin+taurine (same doses), respectively. Nitrite/nitrate (NOx), ADMA and Hcy levels were measured. There was a significant increase of NOx, ADMA and Hcy in endotoxemia (p<0.05). Taurine treatment elevated NOx levels significantly (p<0.01) in taurine and LPS + taurine group compared to control group, while it reduced NOx levels compared to LPS group. In contrast, taurine decreased ADMA levels to the control level both in taurine and taurine+LPS group compared to LPS. Hcy levels increased significantly compared to taurine group (p<0.05) and did not change compared to LPS group. Taurine was effective on ADMA-NO relationship whereas no beneficial effect was observed in Hcy levels (p<0.05).

  14. Role of the p38 MAPK signaling pathway in asymmetric dimethylarginine induced increase in endothelial permeability%p38丝裂原活化蛋白激酶通路在非对称性二甲基精氨酸诱导内皮细胞通透性增高中的作用

    Institute of Scientific and Technical Information of China (English)

    张东亮; 王丽妍; 张育; 刘文虎

    2011-01-01

    目的 探讨非对称性二甲基精氰酸(ADMA)对单层内皮细胞通透性的影响,以及氧化应激、p38丝裂原活化蛋白激酶(MAPK)通路在此过程中的作用.方法 利用Transwell小室建立单层内皮细胞屏障结构,设立实验组和对照组,实验组经浓度25、50、100、200μmol/LADMA作用24 h和100μmol/LADMA分别刺激细胞4、8、16、24 h,或分别经烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶抑制剂、p38 MAPK抑制剂预处理细胞后再加入ADMA刺激.随后用异硫氰酸荧光素(FITC)标记的右旋糖酐漏出法测定单层内皮细胞的通透系数Pa值,并用免疫荧光染色显示细胞骨架及细胞间连接的形态学改变.结果 ADMA呈剂量及时间依赖性的增加单层内皮细胞的通透性,同时促进内皮细胞中应力纤维的形成并破坏细胞间连接.NADPH氧化酶抑制剂和p38 MAPK抑制剂均可对抗ADMA的上述作用.结论 ADMA通过引起氧化应激,激活p38 MAPK通路,改变细胞骨架及细胞间连接的结构,使单层内皮细胞通透性增高.%Objective To investigate the effect of asymmetric dimethylarginine (ADMA) on the permeability of endothelial monolayer, and study the roles of oxidant streas and the p38 mitogen- activated protein kinase(MAPK) pathway. Methods Human umbilical vein endothelium cells (HUVEC) were cultured on the bottom of the upper well in a Transwell system to establish endothelial monolayer harrier. Experimental group and control group were set for the research. The experimental group were left untreated or incubaced with differenl concentrations of ADMA (25, 50, 100 and 200 μmol/L, respectively) for 24 hours or incubated with 100 μmol/L ADMA for different times(4, 8, 16 and 24 h respectively). Furthermore, the cells were treated with β-nicotinamide adenine dinucleotide 2' -phosphate reduced tetrasodium salt (NADHP) oxidase specific inhibitor or p38 MAPK specific inhibitor before incubation with ADMA. Fluoresceinisothiocyanate

  15. Novel markers of endothelial dysfunction and inflammation in Behçet's disease patients with ocular involvement: epicardial fat thickness, carotid intima media thickness, serum ADMA level, and neutrophil-to-lymphocyte ratio.

    Science.gov (United States)

    Yuksel, Murat; Yildiz, Abdulkadir; Oylumlu, Mustafa; Turkcu, Fatih Mehmet; Bilik, Mehmet Zihni; Ekinci, Aysun; Elbey, Bilal; Tekbas, Ebru; Alan, Sait

    2016-03-01

    The etiology of Behçet's disease (BD) has not been fully elucidated. However, immunological and environmental factors, endothelial dysfunction (ED), and genetic susceptibility have been proposed to play a role. In this study, we aimed to evaluate epicardial fat thickness (EFT) together with serum asymmetric dimethylarginine (ADMA), carotid intima media thickness (CIMT), and neutrophil-to-lymphocyte ratio (NLR) in BD patients with ocular involvement. Thirty-six ocular BD patients (17 active and 19 inactive ocular involvement), and 35 age and sex-matched healthy controls were enrolled to this cross-sectional study. All patients underwent examinations with transthoracic echocardiography and carotid Doppler ultrasound. Serum ADMA levels, CIMT, EFT, and NLR were compared between groups, and their association with disease activity was evaluated. Behçet's disease patients had higher WBC counts, neutrophil counts, NLR, CIMT, EFT values, and serum ADMA levels than do healthy controls. The other biochemical, hematological, and echocardiographic parameters were comparable between the two groups. Behçet's disease duration was positively correlated with EFT and CIMT. Multivariate logistic regression analysis revealed that increased serum ADMA concentration and CIMT are independently associated with BD. Neutrophil counts, NLR, and serum ADMA level were higher, and lymphocyte count was lower in patients with active ocular BD compared to those of inactive ocular BD group. Carotid intima media thickness, serum ADMA level, EFT, and NLR were increased in ocular BD patients compared to healthy subjects. In addition, both serum ADMA level and NLR were associated with disease activity of ocular involvement. Increase in disease duration was associated with increase in CIMT and EFT which suggests that anatomical changes occur in time during the disease course. Increased CIMT, serum ADMA level, EFT, and NLR may provide new clues about the role of ED and inflammation in the

  16. Inhibitors of the Hydrolytic Enzyme Dimethylarginine Dimethylaminohydrolase (DDAH: Discovery, Synthesis and Development

    Directory of Open Access Journals (Sweden)

    Rhys B. Murphy

    2016-05-01

    Full Text Available Dimethylarginine dimethylaminohydrolase (DDAH is a highly conserved hydrolytic enzyme found in numerous species, including bacteria, rodents, and humans. In humans, the DDAH-1 isoform is known to metabolize endogenous asymmetric dimethylarginine (ADMA and monomethyl arginine (l-NMMA, with ADMA proposed to be a putative marker of cardiovascular disease. Current literature reports identify the DDAH family of enzymes as a potential therapeutic target in the regulation of nitric oxide (NO production, mediated via its biochemical interaction with the nitric oxide synthase (NOS family of enzymes. Increased DDAH expression and NO production have been linked to multiple pathological conditions, specifically, cancer, neurodegenerative disorders, and septic shock. As such, the discovery, chemical synthesis, and development of DDAH inhibitors as potential drug candidates represent a growing field of interest. This review article summarizes the current knowledge on DDAH inhibition and the derived pharmacokinetic parameters of the main DDAH inhibitors reported in the literature. Furthermore, current methods of development and chemical synthetic pathways are discussed.

  17. Actin cytoskeleton-dependent pathways for ADMA-induced NF-κB activation and TGF-β high expression in human renal glomerular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Liyan Wang; Dongliang Zhang; Junfang Zheng; Yiduo Feng; Yu Zhang; Wenhu Liu

    2012-01-01

    Asymmetric dimethylarginine (ADMA),an endogenous nitric oxide synthase inhibitor,is considered to be an independent risk factor in the progression of chronic kidney diseases (CKD).It can induce kidney fibrosis by increasing transforming growth factor (TGF)-β1 expression,but its molecular mechanism is unclear.The aim of the present study was to investigate the role of actin cytoskeleton in ADMA-induced TGF-β1 high expression in human renal glomerular endothelial cells (HRGECs).The structure of stress fibers was visualized by immunofluorescence,nuclear factor-κB (NF-κB) DNA-binding activity was assessed by an electrophoretic mobility shift assay and TGF-β1 expression was assessed by western blot analysis.Results showed that ADMA induced the assembly of stress fibers,DNA binding of NF-κB,and increasing expression of TGF-β1.When the dynamics of actin cytoskeleton was perturbed by the actin-depolymerizing agent cytochalasin D and the actin-stabilizing agent jasplakinolide,or ablation of stress fiber bundles by the nicotineamide adenine dinucleotide phosphate oxidase inhibitor apocynin and p38 mitogen-activated protein kinase inhibitor SB203580,ADMA-induced DNA binding of NF-κB and TGF-β1 expression were inhibited.These results revealed an actin cytoskeleton-dependent mechanism in ADMA-induced NF-κB activation and TGF-β1 high expression in HRGECs.The specific targeting of the actin cytoskeleton may be a useful strategy to prevent ADMA-activated kidney fibrosis in CKD.

  18. Protein aiginine methyltransferase 4 and methylated metabolite asymmetric dimethylarginines in polycystic ovary syndrome%精氨酸甲基转移酶4及其产物不对称二甲基精氨酸在多囊卵巢综合征中的初步探讨

    Institute of Scientific and Technical Information of China (English)

    石雯沁; 赵纯全

    2013-01-01

    Objective:To investigate levels of asymmetric dimethylarginines (ADMA) in serum of women with and without polycystic ovary syndrome(PCOS) ,PCOS model rats and control rats,to explore expressions of protein aiginine methyltransferase 4(PRMT4) in ovarian tissues of PCOS model rats and to explore relationship between levels of ADMA and PRMT4 and PCOS. Methods: ELISA was used to investigate levels of ADMA in serum of 49 PCOS patients, 20 normal patients, 20 PCOS model rats and 20 normal rats. Expressions of PRMT4 in ovarian tissues were detected by SP immunohistochemical method (including 20 PCOS model rats and 20 control rats). Results: (l)In human serum,ADMA concentrations were (0.49±0.35) μmol/L and (0.26±0.09) μmol/L in PCOS group and control group respectively,with significant differences between two groups (P=0.00). (2)In rat serum,ADMA concentrations were (0.55 ±0.14) μmol/L and (0.23 ±0.08) μmol/L in PCOS group and control group respectively,with significant differences between two groups(P=0.00). (3)In rat ovarian tissues,PRMT4 integral optical density values were (44.96 ±9.40) μmol/L and (18.27 ± 3.83) μmol/L in PCOS group and control group respectively,with significant differences between two groups(P=0.00). Conclusions:In ovarian tissues,increased expressions of PRMT4 may bring about elevated ADMA level in serum,which causes endothelial dysfunction of PCOS and affects PCOS development.%目的:研究多囊卵巢综合征(polycystic ovary syndrome,PCOS)患者、人正常对照组血清及PCOS模型大鼠、大鼠对照组血清中不对称二甲基精氨酸(asymmetric dimethylarginines,ADMA)的含量,以及PCOS模型大鼠卵巢组织中蛋白质精氨酸甲基转移酶4(protein aiginine methyltransferase 4,PRMT4)的表达情况,研究二者与PCOS之间的关系.方法:运用ELISA测定49例PCOS患者、20例人正常对照组以及20例PCOS模型大鼠、20例大鼠对照组血清中ADMA的含量,并采用免疫组化SP法

  19. Overexpression of dimethylarginine dimethylaminohydrolase 1 attenuates airway inflammation in a mouse model of asthma.

    Directory of Open Access Journals (Sweden)

    Kayla G Kinker

    Full Text Available Levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of nitric oxide synthase, are increased in lung, sputum, exhaled breath condensate and plasma samples from asthma patients. ADMA is metabolized primarily by dimethylarginine dimethylaminohydrolase 1 (DDAH1 and DDAH2. We determined the effect of DDAH1 overexpression on development of allergic inflammation in a mouse model of asthma. The expression of DDAH1 and DDAH2 in mouse lungs was determined by RT-quantitative PCR (qPCR. ADMA levels in bronchoalveolar lavage fluid (BALF and serum samples were determined by mass spectrometry. Wild type and DDAH1-transgenic mice were intratracheally challenged with PBS or house dust mite (HDM. Airway inflammation was assessed by bronchoalveolar lavage (BAL total and differential cell counts. The levels of IgE and IgG1 in BALF and serum samples were determined by ELISA. Gene expression in lungs was determined by RNA-Seq and RT-qPCR. Our data showed that the expression of DDAH1 and DDAH2 was decreased in the lungs of mice following HDM exposure, which correlated with increased ADMA levels in BALF and serum. Transgenic overexpression of DDAH1 resulted in decreased BAL total cell and eosinophil numbers following HDM exposure. Total IgE levels in BALF and serum were decreased in HDM-exposed DDAH1-transgenic mice compared to HDM-exposed wild type mice. RNA-Seq results showed downregulation of genes in the inducible nitric oxide synthase (iNOS signaling pathway in PBS-treated DDAH1-transgenic mice versus PBS-treated wild type mice and downregulation of genes in IL-13/FOXA2 signaling pathway in HDM-treated DDAH1-transgenic mice versus HDM-treated wild type mice. Our findings suggest that decreased expression of DDAH1 and DDAH2 in the lungs may contribute to allergic asthma and overexpression of DDAH1 attenuates allergen-induced airway inflammation through modulation of Th2 responses.

  20. IGF-1 and ADMA Levels Are Inversely Correlated in Nondiabetic Ankylosing Spondylitis Patients Undergoing Anti-TNF-Alpha Therapy

    Directory of Open Access Journals (Sweden)

    Fernanda Genre

    2014-01-01

    Full Text Available Like rheumatoid arthritis, ankylosing spondylitis (AS is also an inflammatory disease associated with accelerated atherosclerosis and the presence of metabolic syndrome (MeS features. AS patients often display osteoporosis as well as new bone formation. Insulin-like growth factor 1 (IGF-1 is a protein involved in both inflammation and bone metabolism. In the present study we assessed whether disease activity, systemic inflammation, MeS features, adipokines, and biomarkers of endothelial activation were associated with IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3 levels in a series of 30 nondiabetic AS patients without CV disease undergoing TNF-α antagonist-infliximab therapy. All determinations were made in the fasting state, immediately before an infliximab infusion. Although no association of IGF-1 and IGFBP-3 levels with angiopoietin-2 or osteopontin was found, an inverse correlation between IGF-1 levels and asymmetric dimethylarginine (ADMA, an endogenous endothelial nitric oxide synthase inhibitor that impairs nitric oxide production and secretion promoting endothelial dysfunction, was found (r=-0.397; P=0.04. However, no significant association was found between IGF-1 and IGFBP-3 levels and disease activity, systemic inflammation, metabolic syndrome features, or adipokines. In conclusion, in nondiabetic patients with AS undergoing periodic anti-TNF-α therapy, IGF-1 and ADMA are inversely correlated.

  1. Correlation of STAT4 and STAT6 expression levels in preeclampsia placenta with sFlt-1 and ADMA generation as well as placental hypoxia

    Institute of Scientific and Technical Information of China (English)

    Dong-Mei Su

    2016-01-01

    Objective:To study the correlation of STAT4 and STAT6 expression levels in preeclampsia placenta with soluble fms-like tyrosine kinase-1 (sFlt-1) and asymmetric dimethylarginine (ADMA) generation as well as placental hypoxia.Methods:A total of 40 pregnant women with preeclampsia were selected as preeclampsia group (PE group) of the study, 40 healthy pregnant women preparing for the delivery in our hospital during the same period were selected as the control group of the study, serum was collected to determine STAT4, STAT6, sFlt-1 and ADMA levels, the placenta was collected to determine STAT4, STAT6, HIF-1α and HSP70 expression, and ultrasonography was conducted to measure uterine spiral artery PI, RI and S/D.Results:STAT4 expression levels in placenta and serum of PE group were significantly higher than those of control group while STAT6 expression levels were significantly lower than those of control group; HSP70 and HIF-1α expression levels in placenta of PE group were significantly higher than those of control group, positively correlated with STAT4 and negatively correlated with STAT6, sFlt-1 and ADMA levels in serum were significantly higher than those of control group, positively correlated with STAT4 and negatively correlated with STAT6, and uterine spiral artery PI, RI and S/D were significantly higher than those of control group, positively related with STAT4 and negatively correlated with STAT6.Conclusions:High expression of STAT4 and low expression of STAT6 in preeclampsia placenta are closely related to placental hypoxia.

  2. Response Characteristics of Nitric Oxide/Asymmetry Dimethyl Arginine in Process of Brucella Infection in Mice%NO/ADMA 在布鲁菌侵染小鼠机体过程中的响应特征

    Institute of Scientific and Technical Information of China (English)

    胡梦薇; 许万云; 刘朋涛; 严国; 汪文伦; 高剑峰

    2016-01-01

    本试验旨在研究布鲁菌侵染小鼠过程中一氧化氮(NO)的作用,以及 NO 和非对称性二甲基精氨酸(ADMA)在此过程的相互作用关系。以布鲁菌标准疫苗株 M5侵染小鼠,首先用小鼠的血清进行虎红平板凝集(RBPT)和试管凝集试验(SAT),再用 Griess 试剂法和 ELISA 法测定对照组和侵染组不同组织和血清中的 NO 和 ADMA 含量,对小鼠肝脏和脾脏的各个侵染时间段进行 CFU 计数观察。结果显示,用布鲁菌 M5侵染小鼠后,RBPT 和 SAT 在14 d 时检测到有阳性反应。侵染组和空白对照组 NO 总含量上变化不大,但侵染组血清中的 NO 含量随时间出现下降,而肝脾中 NO 含量随时间出现上升,其他各组织 NO 含量波动不明显。而 ADMA 的总趋势与 NO 相反。CFU 计数结果显示,小鼠肝脾内布鲁菌的数量在14 d 时一直处于增长状态,28 d 时布鲁菌的数量下降,表明布鲁菌的分裂繁殖和机体 NO 的含量存在一定的关系。%This experiment was aimed to study the role of nitric oxide (NO)in the process of Brucella in-fection in mice,as well as the interaction between NO and asymmetric dimethyl-arginine (ADMA)in this process.Brucella vaccine strain M5 was used to infect mice,firstly the red plate agglutination (RBPT) and tube agglutination test (SAT)were carried out using the sera of mice.The contents of NO and ADMA in different tissues and sera between control group and infection group were detected by Griess reagent method and ELISA method.At the same time,the CFU counts of mice's liver and spleen were observed in each infection period.The results showed that positive reaction were detected in 14 d by RBPT and SAT experiments after using Brucella M5 infection mice.Total NO contents changed little between infection groups and blank control groups.But the contents of NO in the infection group decreased with time,the contents of NO in liver and spleen increased with time,the concents of NO in other

  3. Online trapping and enrichment ultra performance liquid chromatography-tandem mass spectrometry method for sensitive measurement of 'arginine-asymmetric dimethylarginine cycle' biomarkers in human exhaled breath condensate

    Energy Technology Data Exchange (ETDEWEB)

    Di Gangi, Iole Maria, E-mail: giordano@pediatria.unipd.it [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Pirillo, Paola [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Carraro, Silvia [Unit of Allergy and Respiratory Diseases, Department of Women' s and Children' s Health, University of Padova (Italy); Gucciardi, Antonina; Naturale, Mauro [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Baraldi, Eugenio [Unit of Allergy and Respiratory Diseases, Department of Women' s and Children' s Health, University of Padova (Italy); Giordano, Giuseppe [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy)

    2012-11-19

    Highlights: Black-Right-Pointing-Pointer Simultaneous quantification of 'arginine-ADMA cycle' metabolites developed in EBC. Black-Right-Pointing-Pointer EBC is a non-invasive matrix highly useful in patients with respiratory diseases. Black-Right-Pointing-Pointer Method, fast, precise and accurate, is suitable in the pediatric clinical studies. Black-Right-Pointing-Pointer Sensitivity is increased using on-line trapping and enrichment-UPLC-MS/MS method. Black-Right-Pointing-Pointer EBC measurements in asthmatic adolescents confirm that ADMA is increased in asthma. - Abstract: Background: Exhaled breath condensate (EBC) is a biofluid collected non invasively that, enabling the measurement of several biomarkers, has proven useful in the study of airway inflammatory diseases, including asthma, COPD and cystic fibrosis. To the best of our knowledge, there is no previous report of any analytical method to detect ADMA in EBC. Objectives: Aim of this work was to develop an online sample trapping and enrichment system, coupled with an UPLC-MS/MS method, for simultaneous quantification of seven metabolites related to 'Arginine-ADMA cycle', using the isotopic dilution. Methods: Butylated EBC samples were trapped in an online cartridge, washed before and after each injection with cleanup solution to remove matrix components and switched inline into the high pressure analytical column. Multiple reaction monitoring in positive mode was used for analyte quantification by tandem mass spectrometry. Results: Validation studies were performed in EBC to examine accuracy, precision and robustness of the method. For each compound, the calibration curves showed a coefficient of correlation (r{sup 2}) greater than 0.992. Accuracy (%Bias) was <3% except for NMMA and H-Arg (<20%), intra- and inter-assay precision (expressed as CV%) were within {+-}20% and recovery ranged from 97.1 to 102.8% for all analytes. Inter-day variability analysis on 20 EBC of adult subjects did

  4. FXR Agonist INT-747 Upregulates DDAH Expression and Enhances Insulin Sensitivity in High-Salt Fed Dahl Rats

    OpenAIRE

    Ghebremariam, Yohannes T; Keisuke Yamada; Lee, Jerry C.; Christine L C Johnson; Dorothee Atzler; Maike Anderssohn; Rani Agrawal; John P. Higgins; Patterson, Andrew J.; Böger, Rainer H.; Cooke, John P.

    2013-01-01

    AIMS: Genetic and pharmacological studies have shown that impairment of the nitric oxide (NO) synthase (NOS) pathway is associated with hypertension and insulin-resistance (IR). In addition, inhibition of NOS by the endogenous inhibitor, asymmetric dimethylarginine (ADMA), may also result in hypertension and IR. On the other hand, overexpression of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes ADMA, in mice is associated with lower ADMA, increased NO and enhanced ...

  5. S-nitrosylation of dimethylarginine dimethylaminohydrolase regulates enzyme activity: Further interactions between nitric oxide synthase and dimethylarginine dimethylaminohydrolase

    Science.gov (United States)

    Leiper, James; Murray-Rust, Judith; McDonald, Neil; Vallance, Patrick

    2002-01-01

    The enzyme dimethylarginine dimethylaminohydrolase (DDAH) hydrolyses asymmetrically methylated arginine residues that are endogenously produced inhibitors of nitric oxide synthases (NOS). We and others have proposed that DDAH activity is a key determinant of intracellular methylarginine concentrations and that factors that regulate the activity of DDAH may modulate nitric oxide (NO) production in vivo. We recently solved the crystal structure of a bacterial DDAH and identified a Cys-His-Glu catalytic triad [Murray-Rust, J., Leiper, J. M., McAlister, M., Phelan, J., Tilley, S., Santa Maria, J., Vallance, P. & McDonald, N. (2001) Nat. Struct. Biol. 8, 679–683]. The presence of a reactive cysteine residue (Cys-249) in the active site of DDAH raised the possibility that DDAH activity might be directly regulated by S-nitrosylation of this residue by NO. In the present study, we demonstrate that recombinant DDAH is reversibly inhibited after incubation with NO donors in vitro. Similarly mammalian DDAH in cytosolic extracts is also reversibly inhibited by NO donors. In cultured endothelial cells, heterologously expressed human DDAH II was S-nitrosylated after cytokine induced expression of the inducible NOS isoforms. The implication of these findings is that under certain conditions when NO generation increases, S-nitrosylation diminishes DDAH activity and this would be expected to lead to accumulation of asymmetric dimethylarginine and inhibition of NOS. This observation may help explain why expression of iNOS often leads to inhibition of activity of constitutively expressed NOS isozymes. We also identify Cys-His-Glu as a nitrosylation motif that is conserved in a family of arginine handling enzymes. PMID:12370443

  6. Effects of atorvastatin on ADMA and ALT in patients with coronary heart disease combined with non-alcoholic fatty liver disease%阿托伐他汀对冠心病合并非酒精性脂肪肝患者ADMA及ALT的影响

    Institute of Scientific and Technical Information of China (English)

    杜丽波; 何兆初; 方向明; 刘振国; 何伟源

    2012-01-01

    目的 观察冠状动脉粥样硬化性心脏病(冠心病)合并非酒精性脂肪肝患者服用阿托伐他汀前后血清非对称性二甲基精氨酸(asymmetric dimethylarginine,ADMA)、高敏C反应蛋白(high sensitively C reactive protein,hsCRP)、丙氨酸转氨酶(alanine aminotransferase,ALT)、天冬氨酸转氨酶(aspartate aminotransferase,AST)及γ-谷氨酰转肽酶(γ-glutamyltranspetidase,γGT)浓度,以评价该药的疗效及安全性.方法 按电脑数字随机表法选择广州医学院附属第一医院心血管内科冠心病合并非酒精性脂肪肝的患者80例,服用阿托伐他汀2年,分别测定治疗前后血清ADMA、hsCRP、ALT、AST、γ-GT、总胆固醇、三酰甘油、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇浓度,并进行比较.结果 治疗后患者的血清ADMA[ (2.77±0.35) μmol/L vs.(3.78±0.47) μmol/L,P<0.05]、ALT[ (34.2±9.3)U/L vs.(83.4±16.7)U/L,P<0.05]及hsCRP[( 1.58±0.70)μg/L vs.(2.85±0.63) μg/L,P< 0.05]浓度均有下降,差异有统计学意义;AST、γ-GT及高密度脂蛋白胆固醇、低密度脂蛋白胆固醇等指标得到了改善,且差异具有统计学意义(P<0 05).结论 冠心病合并非酒精性脂肪肝患者服用阿托伐他汀疗效确切,安全性良好.%Objectives To observed the influence of atorvastatin on serum concentrations of asymmetric dimethylarginine (ADMA),high sensitively C reactive protein (hsCRP) and alanine aminotransferase (ALT) , aspartate aminotransferase (AST) ,γ-glutamyltranspetidase (7GT) in patients with coronary heart disease combined with non-alcoholic fatty liver disease for evaluating safety and effect of atorvastatin. Methods Eighty patients with coronary heart disease combined with non-alcoholic fatty liver disease who had taken atorvastatin for 2 years were randomly selected in this study in The First Affiliated Hospital of Guangzhou Medical College. Serum concentrations of ADMA, hsCRP, ALT, AST, 7GT, total cholesterol

  7. Compositional Analysis of Asymmetric and Symmetric Dimethylated H3R2 Using Liquid Chromatography-Tandem Mass Spectrometry-Based Targeted Proteomics.

    Science.gov (United States)

    Xu, Qingqing; Xu, Feifei; Liu, Liang; Chen, Yun

    2016-09-01

    Protein arginine methylation is one of the common post-translational modifications in cellular processes. To date, two isomeric forms of dimethylated arginine have been identified: asymmetric N(G),N(G)-dimethylarginine (aDMA), and symmetric N(G),N'(G)-dimethylarginine (sDMA). Evidence indicated that these isomers can coexist and have different or even opposite functions, with aDMA and sDMA forms of arginine 2 on histone H3 (i.e., H3R2me2a and H3R2me2s) being an example. Thus, specific detection and quantification of each isomeric form is important. Current methods are capable of predicting and detecting thousands of methylarginine sites in proteins, whereas differentiation and stoichiometric measurement of dimethylated protein isomers are still challenging. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS)-based targeted proteomics has emerged as a promising technique for site-specific quantification of protein methylation using enzymatic peptides as surrogates of target proteins. However, it should be pointed out that a routine targeted proteomics strategy cannot easily distinguish sDMA- and aDMA-containing surrogate peptides due to their common nature. The estimated amount should be considered as the sum of both arginine dimethylated isomers. In this study, compositional analysis based on a linear algebra algorithm as an add-on to targeted proteomics was employed to quantify H3R2me2a and H3R2me2s (i.e., surrogate peptides of AR(me2a)TK(me1/2)QT and AR(me2s)TK(me1/2)QT). To achieve this simultaneous quantification, a targeted proteomics assay was developed and validated for each isomer first. With the slope and intercept of their calibration curves for each multiple reaction monitoring (MRM) transition, linear algebraic equations were derived. Using a series of mock mixtures consisting of isomers in varying concentrations, the reliability of the method was confirmed. Finally, the H3R2 dimethylation status was analyzed in normal MCF-10A cells

  8. 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

  9. Nitric oxide increases myocardial efficiency in the hypoxia-tolerant turtle Trachemys scripta

    DEFF Research Database (Denmark)

    Misfeldt, Mikkel; Fago, Angela; Gesser, Hans

    2009-01-01

    was primarily due to a decrease in O2 consumption and may represent an increase in the twitch force obtained per ATP and/or in the ATP obtained per O2. Lactate production during hypoxia did not differ between preparations treated with either L-arginine or asymmetric dimethylarginine (ADMA), an inhibitor of NOS......, suggesting that NO does not elicit a compensatory increase in anaerobic metabolism. ADMA did not reverse the effects of L-arginine on O2 consumption significantly, although pre-treatment with ADMA abolished the effect of L-arginine, consistent with the competitive binding of L-arginine and ADMA to NOS...

  10. The L-arginine Pathway in Acute Ischemic Stroke and Severe Carotid Stenosis

    DEFF Research Database (Denmark)

    Molnar, Tihamer; Pusch, Gabriella; Papp, Viktoria;

    2014-01-01

    BACKGROUND: Endothelial dysfunction is associated with increased levels of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) resulting in a decreased production of nitric oxide, which regulates the vascular tone. METHODS: Patients with acute ischemic stroke (AIS, n = 55......) and asymptomatic significant carotid stenosis (AsCS, n = 44) were prospectively investigated. L-arginine, ADMA, SDMA, S100 B, and high-sensitivity C-reactive protein (hsCRP) were serially measured within 6 hours after the onset of stroke, at 24 and 72 poststroke hours. All markers were compared with healthy...

  11. Dimethylarginine dimethylaminohydrolase 2 promotes tumor angiogenesis in lung adenocarcinoma.

    Science.gov (United States)

    Shiozawa, Toshihiro; Iyama, Shinji; Toshima, Shotaro; Sakata, Akiko; Usui, Shingo; Minami, Yuko; Sato, Yukio; Hizawa, Nobuyuki; Noguchi, Masayuki

    2016-02-01

    Although embryonal proteins have been used as tumor marker, most are not useful for detection of early malignancy. In the present study, we developed mouse monoclonal antibodies against fetal lung of miniature swine, and screened them to find an embryonal protein that is produced at the early stage of malignancy, focusing on lung adenocarcinoma. We found an antibody clone that specifically stained stroma of lung adenocarcinoma. LC-MS/MS identified the protein recognized by this clone as dimethylarginine dimethylaminohydrolase 2 (DDAH2), an enzyme known for antiatherosclerotic activity. DDAH2 was found to be expressed in fibroblasts of stroma of malignancies, with higher expression in minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma than in adenocarcinoma in situ (AIS). Moreover, tumors with high stromal expression of DDAH2 had a poorer prognosis than those without. In vitro analysis showed that DDAH2 increases expression of endothelial nitric oxide synthase (eNOS), inducing proliferation and capillary-like tube formation of vascular endothelial cells. In resected human tissues, eNOS also showed higher expression in invasive adenocarcinoma than in AIS and normal lung, similarly to DDAH2. Our data indicate that expression of DDAH2 is associated with invasiveness of lung adenocarcinoma via tumor angiogenesis. DDAH2 expression might be a prognostic factor in lung adenocarcinoma.

  12. Relationship between protecitve effect of probucol on endothelial cells and asymmetrical dimethylarginine levels

    Institute of Scientific and Technical Information of China (English)

    Jun-linJIANG; Xiao-hongZHANG; Han-wuDENG; Yuan-JianLI

    2004-01-01

    AIM: To investigate the relationship between protective effect of probucol on endothelial cells and endogenous nitric oxide synthase inhibitor levels. METHODS: Endothelial cells were treated with oxidative-low density lipoprotein (ox-LDL) (100 rag/L) or lysophosphatidyl choline (LPC) (5 mg/L) for 48 h, and the release of lactate dehydrogenase (LDH), levels of nitric oxide (NO),

  13. L-Arginine Pathway in COPD Patients with Acute Exacerbation

    DEFF Research Database (Denmark)

    Ruzsics, Istvan; Nagy, Lajos; Keki, Sandor;

    2016-01-01

    (ADMA, SDMA) is related to hypoxia. In COPD, a rise in ADMA results in a shift of L-arginine breakdown, contributing to airway obstruction. We aimed to compare serum levels of ADMA, SDMA and L-arginine in patients with and without AECOPD. METHODS: L-arginine metabolites quantified by high......BACKGROUND: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) remains a major cause of mortality. Clinical criteria of AECOPD are subjective. Biomarkers for AECOPD may aid in the initiation of early treatment. Increased production of asymmetric and symmetric dimethylarginine......-arginine, ADMA and SDMA serum levels. In patients with AECOPD, production of ADMA and SDMA are more pronounced presumably due to more severe hypoxic insult. Methylated arginine derivatives in the sera may help early recognition of AECOPD....

  14. Relationship between Serum Symmetric Dimethylarginine Concentration and Glomerular Filtration Rate in Cats

    OpenAIRE

    Braff, J.; Obare, E.; Elliott, J.; Yerramilli, M.

    2014-01-01

    Background Direct measurement of glomerular filtration rate (GFR) is the preferred method to assess renal function in cats, but it is not widely used in the diagnosis of chronic kidney disease (CKD). In cats with CKD, symmetric dimethylarginine (SDMA) has been shown to increase and to correlate with plasma creatinine concentrations. Hypothesis In cats, reduced GFR corresponds with increased serum SDMA concentration. Animals The study group consisted of ten client‐owned cats whose GFR had been...

  15. Nitric Oxide-Related Biological Pathways in Patients with Major Depression.

    Directory of Open Access Journals (Sweden)

    Andreas Baranyi

    Full Text Available Major depression is a well-known risk factor for cardiovascular diseases and increased mortality following myocardial infarction. However, biomarkers of depression and increased cardiovascular risk are still missing. The aim of this prospective study was to evaluate, whether nitric-oxide (NO related factors for endothelial dysfunction, such as global arginine bioavailability, arginase activity, L-arginine/ADMA ratio and the arginine metabolites asymmetric dimethylarginine (ADMA and symmetric dimethylarginine (SDMA might be biomarkers for depression-induced cardiovascular risk.In 71 in-patients with major depression and 48 healthy controls the Global Arginine Bioavailability Ratio (GABR, arginase activity (arginine/ornithine ratio, the L-arginine/ADMA ratio, ADMA, and SDMA were determined by high-pressure liquid chromatography. Psychiatric and laboratory assessments were obtained at baseline at the time of in-patient admittance and at the time of hospital discharge.The ADMA concentrations in patients with major depression were significantly elevated and the SDMA concentrations were significantly decreased in comparison with the healthy controls. Even after a first improvement of depression, ADMA and SDMA levels remained nearly unchanged. In addition, after a first improvement of depression at the time of hospital discharge, a significant decrease in arginase activity, an increased L-arginine/ADMA ratio and a trend for increased global arginine bioavailability were observed.Our study results are evidence that in patients with major depression ADMA and SDMA might be biomarkers to indicate an increased cardiovascular threat due to depression-triggered NO reduction. GABR, the L-arginine/ADMA ratio and arginase activity might be indicators of therapy success and increased NO production after remission.

  16. Nitric Oxide Manipulation: A Therapeutic Target for Peripheral Arterial Disease?

    Directory of Open Access Journals (Sweden)

    Gareth Williams

    2012-01-01

    Full Text Available Peripheral Arterial Disease (PAD is a cause of significant morbidity and mortality in the Western world. Risk factor modification and endovascular and surgical revascularisation are the main treatment options at present. However, a significant number of patients still require major amputation. There is evidence that nitric oxide (NO and its endogenous inhibitor asymmetric dimethylarginine (ADMA play significant roles in the pathophysiology of PAD. This paper reviews experimental work implicating the ADMA-DDAH-NO pathway in PAD, focussing on both the vascular dysfunction and effects within the ischaemic muscle, and examines the potential of manipulating this pathway as a novel adjunct therapy in PAD.

  17. Symmetric Dimethylarginine: Improving the Diagnosis and Staging of Chronic Kidney Disease in Small Animals.

    Science.gov (United States)

    Relford, Roberta; Robertson, Jane; Clements, Celeste

    2016-11-01

    Chronic kidney disease (CKD) is a common condition in cats and dogs, traditionally diagnosed after substantial loss of kidney function when serum creatinine concentrations increase. Symmetric dimethylarginine (SDMA) is a sensitive circulating kidney biomarker whose concentrations increase earlier than creatinine as glomerular filtration rate decreases. Unlike creatinine SDMA is unaffected by lean body mass. The IDEXX SDMA test introduces a clinically relevant and reliable tool for the diagnosis and management of kidney disease. SDMA has been provisionally incorporated into the International Renal Interest Society guidelines for CKD to aid staging and targeted treatment of early and advanced disease. PMID:27499007

  18. Measurement of arginine metabolites: regulators of nitric oxide metabolism.

    Science.gov (United States)

    Augustine, Molly S; Rogers, Lynette K

    2013-01-01

    Arginine is the substrate for nitric oxide synthases (NOS), and arginine availability regulates the production of nitric oxide. Through the activity of methyltransferases, arginine can be methylated to form monomethylarginine (NMMA), asymmetrical dimethylarginine (ADMA), and symmetrical dimethylarginine (SDMA). NMMA and ADMA directly inhibit NOS, whereas SDMA inhibits the cellular import of arginine through the cationic amino acid transporter. Increased levels of methylarginine compounds have been associated with many diseases including atherosclerosis, renal failure, pulmonary hypertension, and preeclampsia. Previous HPLC methods to measure these molecules rely on derivatization with ortho-phthalaldehyde, which is unstable and requires immediate pre- or post-column reactions. We have identified a new fluorometric agent that is stable for at least 1 week and provides chromatographic properties that facilitate separation of these chemically similar compounds by reverse phase chromatography. PMID:24510541

  19. Pharmacology and clinical pharmacology of methylarginines used as inhibitors of nitric oxide synthases.

    Science.gov (United States)

    Kittel, Anja; Maas, Renke

    2014-01-01

    The methylarginines asymmetric dimethylarginine (ADMA) and monomethylarginine (L-NMMA) are endogenously formed inhibitors of nitric oxide synthases (NOS), which have extensively been investigated as risk markers and used as pharmacological tools to study the L-arginine-nitric oxide (NO) pathway in vitro and in vivo. It is the aim of the present review to summarize the clinical and experimental data on the pharmacological properties that are of relevance when planning and conducting experiments and clinical studies involving methylarginines. Key pharmacodynamic and pharmacokinetic data including IC50 values of ADMA and L-NMMA for NOS isoforms and transport proteins, as well as metabolism by dimethylarginine dimethylaminohydrolases (DDAH1 and DDAH2) and alanine-glyoxylate aminotransferase 2 (AGXT2) are discussed.

  20. Transsulfuration pathway thiols and methylated arginines: the Hunter Community Study.

    Directory of Open Access Journals (Sweden)

    Arduino A Mangoni

    Full Text Available BACKGROUND: Serum homocysteine, when studied singly, has been reported to be positively associated both with the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine [ADMA, via inhibition of dimethylarginine dimethylaminohydrolase (DDAH activity] and with symmetric dimethylarginine (SDMA. We investigated combined associations between transsulfuration pathway thiols, including homocysteine, and serum ADMA and SDMA concentrations at population level. METHODS: Data on clinical and demographic characteristics, medication exposure, C-reactive protein, serum ADMA and SDMA (LC-MS/MS, and thiols (homocysteine, cysteine, taurine, glutamylcysteine, total glutathione, and cysteinylglycine; capillary electrophoresis were collected from a sample of the Hunter Community Study on human ageing [n = 498, median age (IQR = 64 (60-70 years]. RESULTS: REGRESSION ANALYSIS SHOWED THAT: a age (P = 0.001, gender (P = 0.03, lower estimated glomerular filtration rate (eGFR, P = 0.08, body mass index (P = 0.008, treatment with beta-blockers (P = 0.03, homocysteine (P = 0.02, and glutamylcysteine (P = 0.003 were independently associated with higher ADMA concentrations; and b age (P = 0.001, absence of diabetes (P = 0.001, lower body mass index (P = 0.01, lower eGFR (P<0.001, cysteine (P = 0.007, and glutamylcysteine (P < 0.001 were independently associated with higher SDMA concentrations. No significant associations were observed between methylated arginines and either glutathione or taurine concentrations. CONCLUSIONS: After adjusting for clinical, demographic, biochemical, and pharmacological confounders the combined assessment of transsulfuration pathway thiols shows that glutamylcysteine has the strongest and positive independent associations with ADMA and SDMA. Whether this reflects a direct effect of glutamylcysteine on DDAH activity (for ADMA and/or cationic amino acid transport requires further investigations.

  1. HIV replication, inflammation, and the effect of starting antiretroviral therapy on plasma asymmetric dimethylarginine, a novel marker of endothelial dysfunction

    DEFF Research Database (Denmark)

    Baker, Jason V; Neuhaus, Jacqueline; Duprez, Daniel;

    2012-01-01

    HIV infection is associated with premature development of cardiovascular disease. Understanding the effects of HIV replication on endothelial dysfunction and platelet activation may identify treatment targets to reduce cardiovascular disease risk.......HIV infection is associated with premature development of cardiovascular disease. Understanding the effects of HIV replication on endothelial dysfunction and platelet activation may identify treatment targets to reduce cardiovascular disease risk....

  2. Arginines Plasma Concentration and Oxidative Stress in Mild to Moderate COPD

    Science.gov (United States)

    Zinellu, Angelo; Fois, Alessandro Giuseppe; Sotgia, Salvatore; Sotgiu, Elisabetta; Zinellu, Elisabetta; Bifulco, Fabiana; Mangoni, Arduino A; Pirina, Pietro; Carru, Ciriaco

    2016-01-01

    Background Elevated plasma concentrations of the endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) have been observed in respiratory conditions such as asthma and cystic fibrosis. Since oxidative stress has been shown to increase the activity of arginine methylating enzymes, hence increased ADMA synthesis, and to reduce ADMA degrading enzymes, hence increased ADMA concentrations, we assessed methylated arginines concentrations in chronic obstructive pulmonary disease (COPD), a disease characterized by increased oxidative stress. Methods Plasma arginine, ADMA and symmetric dimethylarginine (SDMA), oxidative stress markers (thiobarbituric acid reactive substances, TBARS, and plasma proteins SH, PSH) and antioxidants (taurine and paraoxonase 1, PON1, activity) were measured in 43 COPD patients with mild (n = 29) or moderate (n = 14) disease and 43 age- and sex-matched controls. Results TBARS significantly increased with COPD presence and severity (median 2.93 vs 3.18 vs 3.64 μmol/L, respectively in controls, mild and moderate group, p<0.0001 by ANOVA) whereas PSH decreased (6.69±1.15 vs 6.04±0.85 vs 5.33±0.96 μmol/gr prot, p<0.0001 by ANOVA). Increased ADMA/arginine ratio, primarily due to reduced arginine concentrations, was also observed with COPD presence and severity (median 0.0067 vs 0.0075 vs 0.0100, p<0.0001 by ANOVA). In multiple logistic regression analysis, only TBARS (OR 0.44, 95% CI 0.25–0.77; p = 0.0045) and ADMA/Arginine ratio (OR 1.72, 95% CI 2.27–13.05; p = 0.02) were independently associated with COPD severity. Conclusion COPD presence and severity are associated with increased oxidative stress and alterations in arginine metabolism. The reduced arginine concentrations in COPD may offer a new target for therapeutic interventions increasing arginine availability. PMID:27479314

  3. Comparison of Serum Concentrations of Symmetric Dimethylarginine and Creatinine as Kidney Function Biomarkers in Cats with Chronic Kidney Disease

    OpenAIRE

    Hall, J.A.; Obare, E.; Yerramilli, M.; Jewell, D.E.

    2014-01-01

    Background Symmetric dimethylarginine (SDMA) has been shown to be an accurate and precise biomarker for calculating estimated glomerular filtration rate (GFR) in humans, as well as a more sensitive biomarker than serum creatinine concentration (sCr) for assessing renal dysfunction. Objectives The purpose of this retrospective study was to report on the utility of measuring serum SDMA concentrations in cats for detection of chronic kidney disease (CKD) before diagnosis by conventional measurem...

  4. [Effect of sanatorium treatment on endothelial function in children with primary arterial hypertension].

    Science.gov (United States)

    Ianina, T Iu

    2014-01-01

    To study the effect of sanatorium treatment (ST) using sodium chloride baths and metabolic drug mildronat on the dynamics of the ambulatory blood pressure monitoring (ABPM), markers of endothelial function in children with primary arterial hypertension (PAH). ABPM and held defined level of asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1) and nitric oxide (NO) in the serum of 114 children with PAH aged 12-17. The positive dynamics of ABPM in all groups, but significantly (P metabolic therapy, but significantly (P metabolic therapy. Analysis of ET-1 and ADMA at ST in conjunction with therapy and metabolic rate of sodium chloride baths there was a significant (P metabolic therapy helps to reduce average daily blood pressure, normalization of functional activity of the endothelium as a normalization of the synthesis of NO (P < 0.,001), a significant decrease of ET-1 (P < 0.01) and ADMA (P < 0.01). PMID:24908958

  5. 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

  6. Beneficial metabolic effects of nateglinide versus acarbose in patients with newly-diagnosed type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    Hong-wei GAO; Chao XIE; Hai-ning WANG; Yu-jing LIN; Tian-pei HONG

    2007-01-01

    Aim: To investigate the acute and chronic effects of nateglinide versus acarbose on plasma asymmetric dimethylarginine (ADMA) levels and lipid profiles in patients with newly-diagnosed type 2 diabetes. Methods: A crossover trial of nateglinide and acarbose was conducted on 16 drug-naive patients with newly-diagnosed type 2 diabetes during a total period of 9 weeks. Plasma glucose, serum insulin, free fatty acids (FFA), lipids and lipoproteins, and plasma ADMA were measured. Results: The efficiencies of a single dose of nateglinide (120 mg) and acarbose (50 mg) for lowering postprandial hyperglycemia were similar. Com-pared to acarbose, nateglinide significantly increased postprandial insulin release after a standard meal test in patients with type 2 diabetes. Nateglinide acutely decreased postprandial 120 min FFA concentrations and 240 min ADMA levels more significantly than acarbose. The fasting high-density lipoprotein choles-terol level increased and the low-density lipoprotein cholesterol level decreased significantly, but the fasting levels of triglycerides, total cholesterol, and ADMA were unchanged after 4 weeks of treatment with nateglinide. Acarbose did not affect fasting lipid profiles or the ADMA levels after 4 weeks of treatment.Conclusion: These results suggest that the reduction of postprandial FFA and ADMA concentrations induced by nateglinide may be associated with the partial restoration of early-phase insulin secretion and may impart a cardiovascular advantage in comparison with acarbose.

  7. Effect of simvastatin on endothelium-dependent vasorelaxation and endogenous nitric oxide synthase inhibitor

    Institute of Scientific and Technical Information of China (English)

    Jun-lin JIANG; De-jian JIANG; Yu-hai TANG; Nian-sheng LI; Han-wu DENG; Yuan-jian LI

    2004-01-01

    AIM: To investigate the effect of simvastatin on endothelium-dependent vasorelaxation and endogenous nitric oxide synthesis inhibitor asymmetric dimethylarginine (ADMA) in rats and cultured ECV304 cells. METHODS: Endothelial injury was induced by a single injection of low density lipoprotein (LDL) (4 mg/kg, 48 h) in rats or incubation with LDL (300 mg/L) or oxidative-modified LDL (100 mg/L) in cultured ECV304 cells, and vasodilator responses to acetylcholine (ACh) in the aortic rings and the level of ADMA, nitrite/nitrate (NO) and tumor necrosis factoralpha (TNF-α) in the serum or cultured medium were determined. And the adhesion of the monocytes to endothelial cells and the activity of dimethylarginine dimethylaminohydrolase (DDAH) in the cultured ECV304 cells were measured. RESULTS: A single injection of LDL decreased endothelium-dependent relaxation to ACh, markedly increased the serum level of endogenous ADMA and TNF-α, and reduced serum level of NO. Pretreatment with simvastatin (30 or 60 mg/kg) markedly attenuated inhibition of vasodilator responses to ACh, the increased level of TNF-α and the decreased level of NO by LDL, but no effect on serum concentration of endogenous ADMA. In cultured ECV304 cells, LDL or ox-LDL markedly increased the level of ADMA and TNF-α and potentiated the adhesion of monocytes to endothelial cells, concomitantly with a significantly decrease in the activity of DDAH and serum level of NO. Pretreatment with simvastatin (0.1, 0.5, or 2.5 μmol/L) markedly decreased the level of TNFo and the adhesion of monocytes to endothelial cells, but did not affect the concentration of endogenous ADMA and the activity of DDAH. CONCLUSION: Simvastatin protect the vascular endothelium against the damages induced by LDL or ox-LDL in rats or cultured ECV304 cells, and the beneficial effects of simvastatin may be related to the reduction of inflammatory cytokine TNF-o level.

  8. Differential effects of arginine methylation on diastolic dysfunction and disease progression in patients with chronic systolic heart failure

    Science.gov (United States)

    Wilson Tang, Wai Hong; Tong, Wilson; Shrestha, Kevin; Wang, Zeneng; Levison, Bruce S.; Delfraino, Brian; Hu, Bo; Troughton, Richard W.; Klein, Allan L.; Hazen, Stanley L.

    2008-01-01

    Aims To investigate the association of arginine methylation with myocardial function and prognosis in chronic systolic heart failure patients. Methods and results Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), as well as N-mono-methylarginine (MMA) and methyl-lysine, were simultaneously measured by tandem mass spectrometry in 132 patients with chronic systolic heart failure with echocardiographic evaluation and follow-up. Increasing ADMA and SDMA levels were associated with elevated natriuretic peptide levels (both P < 0.001), and increasing SDMA levels were associated with worsening renal function (P < 0.001). Higher plasma levels of methylated arginine metabolites (but not methyl-lysine) were associated with the presence of left ventricular (LV) diastolic dysfunction (E/septal E′, Spearman's r = 0.31–0.36, P < 0.001). Patients taking beta-blockers had lower ADMA levels than those not taking beta-blockers [0.42 (0.33, 0.50) vs. 0.51 (0.40, 0.58), P < 0.001]. Only increasing ADMA levels were associated with advanced right ventricular (RV) systolic dysfunction. Elevated ADMA levels remained a consistent independent predictor of adverse clinical events (hazard ratio = 1.64, 95% CI: 1.20–2.22, P = 0.002). Conclusion In chronic systolic heart failure, accumulation of methylated arginine metabolites is associated with the presence of LV diastolic dysfunction. Among the methylated derivatives of arginine, ADMA provides the strongest independent prediction of disease progression and adverse long-term outcomes. PMID:18687662

  9. 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

  10. Packed red blood cells are an abundant and proximate potential source of nitric oxide synthase inhibition.

    Directory of Open Access Journals (Sweden)

    Charles F Zwemer

    Full Text Available We determined, for packed red blood cells (PRBC and fresh frozen plasma, the maximum content, and ability to release the endogenous nitric oxide synthase (NOS inhibitors asymmetric dimethylarginine (ADMA and monomethylarginine (LNMMA.ADMA and LNMMA are near equipotent NOS inhibitors forming blood's total NOS inhibitory content. The balance between removal from, and addition to plasma determines their free concentrations. Removal from plasma is by well-characterized specific hydrolases while formation is restricted to posttranslational protein methylation. When released into plasma they can readily enter endothelial cells and inhibit NOS. Fresh rat and human whole blood contain substantial protein incorporated ADMA however; the maximum content of ADMA and LNMMA in PRBC and fresh frozen plasma has not been determined.We measured total (free and protein incorporated ADMA and LNMMA content in PRBCs and fresh frozen plasma, as well as their incubation induced release, using HPLC with fluorescence detection. We tested the hypothesis that PRBC and fresh frozen plasma contain substantial inhibitory methylarginines that can be released chemically by complete in vitro acid hydrolysis or physiologically at 37°C by enzymatic blood proteolysis.In vitro strong-acid-hydrolysis revealed a large PRBC reservoir of ADMA (54.5 ± 9.7 µM and LNMMA (58.9 ± 28.9 μM that persisted over 42-d at 6° or -80°C. In vitro 5h incubation at 37°C nearly doubled free ADMA and LNMMNA concentration from PRBCs while no change was detected in fresh frozen plasma.The compelling physiological ramifications are that regardless of storage age, 1 PRBCs can rapidly release pathologically relevant quantities of ADMA and LNMMA when incubated and 2 PRBCs have a protein-incorporated inhibitory methylarginines reservoir 100 times that of normal free inhibitory methylarginines in blood and thus could represent a clinically relevant and proximate risk for iatrogenic NOS inhibition upon

  11. Atrial Fibrillation Is Associated with a Marker of Endothelial Function and Oxidative Stress in Patients with Acute Myocardial Infarction.

    Directory of Open Access Journals (Sweden)

    Karim Stamboul

    Full Text Available Atrial fibrillation (AF, whether silent or symptomatic, is a frequent and severe complication of acute myocardial infarction (AMI. Asymmetric dimethylarginine (ADMA, an endogenous eNOS inhibitor, is a risk factor for endothelial dysfunction. We addressed the relationship between ADMA plasma levels and AF occurrence in AMI.273 patients hospitalized for AMI were included. Continuous electrocardiographic monitoring (CEM ≥48 hours was recorded and ADMA was measured by High Performance Liquid Chromatography on admission blood sample.The incidence of silent and symptomatic AF was 39(14% and 29 (11%, respectively. AF patients were markedly older than patients without AF (≈ 20 y. There was a trend towards higher ADMA levels in patients with symptomatic AF than in patients with silent AF or no AF (0.53 vs 0.49 and 0.49 μmol/L, respectively, p = 0.18,. After matching on age, we found that patients with symptomatic AF had a higher heart rate on admission and a higher rate of patients with LV dysfunction (28% vs. 3%, p = 0.025. Patients who developed symptomatic AF had a higher ADMA level than patients without AF (0.53 vs. 0.43 μmol/L; p = 0.001. Multivariate logistic regression analysis to estimate symptomatic AF occurrence showed that ADMA was independently associated with symptomatic AF (OR: 2.46 [1.21-5.00], p = 0.013 beyond history of AF, LVEF<40% and elevated HR.We show that high ADMA level is associated with the occurrence of AF. Although no causative role can be concluded from our observational study, our work further supports the hypothesis that endothelial dysfunction is involved in the pathogenesis of AF in AMI.

  12. FXR agonist INT-747 upregulates DDAH expression and enhances insulin sensitivity in high-salt fed Dahl rats.

    Directory of Open Access Journals (Sweden)

    Yohannes T Ghebremariam

    Full Text Available AIMS: Genetic and pharmacological studies have shown that impairment of the nitric oxide (NO synthase (NOS pathway is associated with hypertension and insulin-resistance (IR. In addition, inhibition of NOS by the endogenous inhibitor, asymmetric dimethylarginine (ADMA, may also result in hypertension and IR. On the other hand, overexpression of dimethylarginine dimethylaminohydrolase (DDAH, an enzyme that metabolizes ADMA, in mice is associated with lower ADMA, increased NO and enhanced insulin sensitivity. Since DDAH carries a farnesoid X receptor (FXR-responsive element, we aimed to upregulate its expression by an FXR-agonist, INT-747, and evaluate its effect on blood pressure and insulin sensitivity. METHODS AND RESULTS: In this study, we evaluated the in vivo effect of INT-747 on tissue DDAH expression and insulin sensitivity in the Dahl rat model of salt-sensitive hypertension and IR (Dahl-SS. Our data indicates that high salt (HS diet significantly increased systemic blood pressure. In addition, HS diet downregulated tissue DDAH expression while INT-747 protected the loss in DDAH expression and enhanced insulin sensitivity compared to vehicle controls. CONCLUSION: Our study may provide the basis for a new therapeutic approach for IR by modulating DDAH expression and/or activity using small molecules.

  13. Effects of breed, gender, exercise and white-coat effect on markers of endothelial function in dogs

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Holte, A.V.; Mogensen, T.;

    2007-01-01

    This study examines how systemic biomarkers of endothelial function and nitric oxide metabolism are affected by exercise in dogs. Furthermore, breed variation and white-coat effect have been tested by sampling three different dog breeds both in their home and in a clinical setting. Short...... significantly higher when the sample was taken in the laboratory cf. at home, whereas ADMA and L-arginine were significantly lower. In conclusion, both short-term exercise and white-coat effect influence several plasma markers of endothelial function depending also on the breed and gender of the dogs......-term exercise increased plasma nitrate and nitrite (NOx) and von Willebrand factor (vWf). There was significant difference between Pointers and the small dog breeds Cairn Terriers and Cavalier King Charles Spaniels in the general plasma levels of vWf and asymmetric dimethylarginine (ADMA9. NOx and vWf were...

  14. Overexpression of Dimethylarginine Dimethylaminohydrolase Enhances Tumor Hypoxia: An Insight into the Relationship of Hypoxia and Angiogenesis In Vivo

    Directory of Open Access Journals (Sweden)

    Vassiliki Kostourou

    2004-07-01

    Full Text Available The oxygenation status of tumors derived from wild-type C6 glioma cells and clone D27 cells overexpressing dimethylarginine dimethylaminohydrolase (DDAH was assessed in vivo using a variety of direct and indirect assays of hypoxia. Clone D27 tumors exhibit a more aggressive and better-vascularized phenotype compared to wild-type C6 gliomas. Immunohistochemical analyses using the 2-nitroimidazole hypoxia marker pimonidazole, fiber optic OxyLite measurements of tumor pO2, and localized 31P magnetic resonance spectroscopy measurements of tumor bioenergetic status and pH clearly demonstrated that the D27 tumors were more hypoxic compared to C6 wild type. In the tumor extracts, only glucose concentrations were significantly lower in the D27 tumors. Elevated Glut-1 expression, a reliable functional marker for hypoxia-inducible factor-1-mediated metabolic adaptation, was observed in the D27 tumors. Together, the data show that overexpression of DDAH results in C6 gliomas that are more hypoxic compared to wild-type tumors, and point strongly to an inverse relationship of tumor oxygenation and angiogenesis in vivo-a concept now being supported by the enhanced understanding of oxygen sensing at the molecular level.

  15. Postnatal high-fat diet leads to spatial deficit, obesity, and central and peripheral inflammation in prenatal dexamethasone adult offspring rats.

    Science.gov (United States)

    Hsieh, Chih-Sung; Li, Shih-Wen; Sheen, Jiunn-Ming; Yu, Hong-Ren; Tiao, Mao-Meng; Tain, You-Lin; Su, Chung-Hao; Huang, Li-Tung

    2016-08-01

    Synthetic glucocorticoids are frequently used in clinical practice for treating pregnant women at risk of preterm delivery, but their long-term effects on the infant brain are largely unknown. Pregnant Sprague-Dawley rats were administered vehicle or dexamethasone between gestational days 14 and 21. Male offspring were then weaned onto either a standard chow or a high-fat diet. The postnatal levels of insulin-like growth factor I (IGF-1), tumor necrosis factor-α (TNF-α), and asymmetric dimethylarginine (ADMA) in the plasma, liver, and brain were examined, as well as the possible effects of prenatal dexamethasone on cognition. We found that a postnatal high-fat diet led to spatial deficits detected by the Morris water maze in adult offspring administered dexamethasone prenatally. The spatial deficit was accompanied by decreased IGF-1 mRNA and increased ADMA levels in the dorsal hippocampus. In peripheral systems, a postnatal high-fat diet resulted in decreased plasma IGF-1, increased plasma corticosterone, increased concentrations of transaminases, TNF-α mRNA, and ADMA in the liver, and associated obesity in adult offspring administered prenatal dexamethasone. In conclusion, a postnatal high-fat diet led to spatial deficits, obesity, and altered levels of IGF-1, TNF-α, and ADMA in the plasma, liver, or brain. PMID:27272689

  16. Effect of cholesterol lowering treatment on plasma markers of endothelial dysfunction in chronic kidney disease.

    Science.gov (United States)

    Zinellu, Angelo; Sotgia, Salvatore; Mangoni, Arduino A; Sotgiu, Elisabetta; Ena, Sara; Satta, Andrea E; Carru, Ciriaco

    2016-09-10

    The elevated cardiovascular morbidity and mortality in chronic kidney disease (CKD) is linked with endothelial dysfunction secondary to the pro-inflammatory and pro-oxidative state typical of this pathology. In consideration of the well-known pleiotropic effect of statins, we investigated the effect of cholesterol lowering treatment on endothelial dysfunction markers (MED), asymmetric dimethylarginine (ADMA), vascular cell (VCAM) and intercellular (ICAM) adhesion molecule. Plasma MED concentrations, inflammation and oxidative stress indices [Kynurenine/Tryptophan (Kyn/Trp) ratio, malondialdehyde (MDA) and allantoin/uric acid (All/UA) ratio] were measured in 30 CKD patients randomized to three cholesterol lowering regimens for 12 months (simvastatin 40mg/day, ezetimibe/simvastatin 10/20mg/day, or ezetimibe/simvastatin 10/40mg/day). Treatment significantly reduced ADMA concentrations in all patients [0.694μmol/L (0.606-0.761) at baseline vs. 0.622μmol/L (0.563-0.681) after treatment, p<0.001]. ADMA reduction was paralleled by a significant decrease of MDA, All/AU ratio and Kyn/Trp ratio, but not VCAM and ICAM plasma concentrations. Cholesterol lowering treatment was associated with a significant reduction in plasma ADMA concentrations in CKD patients. This might be mediated by reduced oxidative stress and inflammation.

  17. Aspirin protected against endothelial damage induced by LDL:role of endogenous NO synthase inhibitors in rats

    Institute of Scientific and Technical Information of China (English)

    Sheng DENG; Pan-yue DENG; Jun-lin JIANG; Feng YE; Jing YU; Tian-lun YANG; Han-wu DENG; Yuan-jian LI

    2004-01-01

    AIM: To study the protective effect of aspirin on damages of the endothelium induced by low-density lipoprotein (LDL), and whether the protective effect of aspirin is related to reduction of nitric oxide synthase inhibitor level.METHODS: Vascular endothelial injury was induced by a single injection of native LDL (4 mg/kg) in rats. Vasodilator responses to acetylcholine (Ach) in the isolated aortic rings were determined, and serum concentrations of asymmetric dimethylarginine (ADMA), malondialdehyde (MDA), tumour necrosis factor-α(TNF-α), and the activity of dimethylaminohydrolase (DDAH) were measured. RESULTS: A single injection of LDL (4 mg/kg)significantly decreased vasodilator responses to Ach, increased the serum level of ADMA, MDA, and TNF-α, and decreased DDAH activity. Aspirin (30 or 100 mg/kg) markedly reduced the inhibition of vasodilator responses to Ach by LDL, and the protective effect of aspirin at the lower dose was greater compared with high-dose aspirin group. Aspirin inhibited the increased level of MDA and TNF-α induced by LDL. Aspirin at the dose of 30 mg/kg,but not at higher dose (100 mg/kg), significantly reduced the concentration of ADMA and increased the activity of DDAH. CONCLUSION: Aspirin at the lower dose (30 mg/kg) protects the endothelium against damages elicited by LDL in vivo, and the protective effect of aspirin on endothelium is related to reduction of ADMA concentration by increasing DDAH activity.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. N-Acetylcysteine Prevents Programmed Hypertension in Male Rat Offspring Born to Suramin-Treated Mothers.

    Science.gov (United States)

    Tain, You-Lin; Hsu, Chien-Ning; Lee, Chien-Te; Lin, Yu-Ju; Tsai, Ching-Chou

    2016-07-01

    Adulthood hypertension can be programmed by preeclampsia. Preeclampsia is associated with an imbalance in vasoactive factors, including nitric oxide (NO), hydrogen sulfide (H2S), and renin-angiotensin system (RAS). We examined whether maternal N-acetylcysteine (NAC) therapy prevented maternal suramin treatment-induced programmed hypertension in offspring and explored the effects of this therapy on NO, H2S, and RAS pathways in the kidneys. Pregnant Sprague-Dawley rats were intraperitoneally administered 60 mg/kg suramin alone on Gestational Days 10 and 11 and were treated with or without 1% NAC through drinking water during the entire pregnancy and lactation period. Male offspring were divided into four groups (n = 8-10/group): control, suramin, NAC, and suramin plus NAC. All rat offspring were euthanized at 12 wk of age. Maternal suramin treatment induced programmed hypertension in male offspring, which was prevented by maternal NAC therapy. Suramin-induced programmed hypertension was associated with increased plasma asymmetric dimethylarginine (ADMA, an NO synthase inhibitor) level, decreased plasma l-arginine-to-ADMA ratio, and decreased renal dimethylarginine dimethylaminohydrolase (an ADMA-metabolizing enzyme) activity. Protective effects of NAC against suramin-induced programmed hypertension were associated with an increase in plasma glutathione level, increase in renal 3-mercaptopyruvate sulfurtransferase level, and restoration of suramin-induced reduction in H2S synthesis in the kidneys. Suramin treatment exerted negligible effect on the RAS pathway in the adult male offspring kidneys. Our data suggested interplay among suramin, ADMA-NO pathway, and H2S synthesis pathway in programmed hypertension. Furthermore, NAC administration in pregnant rats with hypertension prevented programmed hypertension in adult offspring. PMID:27251093

  3. Evaluation of cardiovascular biomarkers in patients with age-related wet macular degeneration

    Directory of Open Access Journals (Sweden)

    Keles S

    2014-08-01

    Full Text Available Sadullah Keles,1 Orhan Ates,1 Baki Kartal,2 Hamit Hakan Alp,3 Metin Ekinci,4 Erdinc Ceylan,2 Osman Ondas,5 Eren Arpali,2 Semih Dogan,6 Kenan Yildirim,7 Mevlut Sait Keles8 1Department of Ophthalmology, School of Medicine, Ataturk University, Erzurum, Turkey; 2Department of Ophthalmology, Regional Training and Research Hospital, Erzurum, Turkey; 3Department of Biochemistry, School of Medicine, Yuzuncu Yil University, Van, Turkey; 4Department of Ophthalmology, School of Medicine, Kafkas University, Kars, Turkey; 5Department of Ophthalmology, Erbaa Government Hospital, Tokat, Turkey; 6Department of Ophthalmology, Kolan Hospital, Istanbul, Turkey; 7Department of Ophthalmology, Igdir Government Hospital, Igdir, Turkey; 8Department of Biochemistry, School of Medicine, Ataturk University, Erzurum, Turkey Aim: To evaluate levels of homocysteine, asymmetric dimethylarginine (ADMA, and nitric oxide (NO, as well as activity of endothelial NO synthase (eNOS, in patients with age-related macular degeneration (AMD.Methods: The levels of homocysteine, ADMA, and NO and activity of eNOS in patients who were diagnosed with wet AMD by fundus fluorescein angiography (n=30 were compared to a control group with no retinal pathology (n=30.Results: Levels of homocysteine and ADMA were found to be significantly higher in the wet AMD group than in the control group (P<0.001, whereas NO levels and eNOS activity were higher in the control group (P<0.001. In the wet AMD group, we detected a 2.64- and 0.33-fold increase in the levels of ADMA and homocysteine, respectively, and a 0.49- and 2.41-fold decrease in the eNOS activity and NO level, respectively.Conclusion: Elevated levels of homocysteine and ADMA were observed in patients with wet AMD. Increased ADMA may be responsible for the diminished eNOS activity found in these patients, which in turn contributes to the decrease in NO levels, which likely plays a role in the pathogenesis of AMD. Keywords: age-related macular

  4. 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.

  5. 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....

  6. 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

  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. Report: investigation of anti-cancer effects of cherry in vitro.

    Science.gov (United States)

    Ogur, Recai; Istanbulluoglu, Hakan; Korkmaz, Ahmet; Barla, Asli; Tekbas, Omer Faruk; Oztas, Emin

    2014-05-01

    Cherry (Prunus Cerasus) is still one of the most popular preserve in Turkish cuisine. Cherry has been traditionally used for the treatment of inflammatory-related symptoms. Recent researches have proved that cherry is a valuable natural source of some important bioactive compounds in human health preservation. Evidence suggests that, cherry consumption may decrease the risk of chronic diseases and cancer. The aim of the present study was to determine the effects of cherry on breast cancer cells lines, asymmetric dimethylarginine (ADMA) level and certain multidrug-resistant bacteria. The cancer cell proliferation activity and analysis of apoptotic-necrotic cells was evaluated by using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and scoring of apoptotic cell nuclei. Measurement of ADMA and the minimum inhibitory concentration was accomplished by HPLC and the micro dilution broth method. The results showed that, extracts of cherry exhibit anti-proliferative activity in mammary adenocarcinoma (MCF-7) & mouse mammary tumor cell (4T1) breast cancer cells lines as well as induction of apoptosis, lower ADMA concentrations in cell cultures treated with cherry extract and antibacterial effects against certain multidrug-resistant bacteria in vitro. These findings may open new horizons for traditional anti-inflammatory product as prophylactic-therapeutic agent from cancer, cardiovascular diseases and multidrug-resistant infections. PMID:24811821

  13. HPLC-MS/MS investigation of biochemical markers for the disclosure of erythropoietin abuse in sports

    Science.gov (United States)

    Appolonova, S. A.; Dikunets, M. A.; Rodchenkov, G. M.

    2009-04-01

    The polypeptide hormone erythropoietin (EPO), which is a forbidden doping drug, was determined by high-performance liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS). The hypothesis about the influence of EPO on the asymmetric dimethylarginine (ADMA)-dimethylargininedime-thylaminohydrolase (DDAH)-NO-synthase system was verified. Changes in this system can serve as indirect biochemical markers of the presence of the forbidden EPO drug in the organism. In the test group, the concentrations of biochemical markers varied from 10 to 40 μg/ml for ADMA and symmetrical DMA (SDMA) and from 0.5 to 10 μg/ml for arginine and citrulline. A single intravenous administration of r-HuEPO (Epocrin, 2000 ME/day) for two volunteers reliably increased ADMA, SDMA, arginine, and citrulline concentrations to 40-270 μg/ml, 40-240μg/ml, 10-60 μg/ml, and 12-140 μg/ml, respectively, with respect to the reference values. The simultaneous increase in arginine, methylarginines, and citrulline contents could be an indirect marker of EPO abuse. The method is recommended for fast screening analysis.

  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. 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...

  16. 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

  17. 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.

  18. 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...

  19. L-Arginine and SDMA Serum Concentrations Are Associated with Subclinical Atherosclerosis in the Study of Health in Pomerania (SHIP.

    Directory of Open Access Journals (Sweden)

    Martin Bahls

    Full Text Available Even though ˪-arginine (ARG derivatives can predict cardiovascular mortality, their role as atherosclerotic biomarkers is unclear. We tested the hypothesis if asymmetric dimethylarginine (ADMA, symmetric dimethylarginine (SDMA and the sum of both (DMA are positively, while ARG and ARG/ADMA ratio are inversely associated with carotid intima-media thickness (cIMT and atherosclerotic plaque in the carotid artery.Cross-sectional data of 1999 subjects (age: 45-81 years; 48.2% ♀ from the population-based Study of Health in Pomerania (SHIP-0 was used. Analysis of variance and logistic regression models were calculated and all adjusted models were corrected for sex, age, smoking status, waist-to-hip ratio and estimated glomerular filtration rate. Increased cIMT (>75th age-sex specific percentile was found in 517 subjects (25.7%, while atherosclerotic plaque was detected in 1413 subjects (70.4%. SDMA tertiles were significantly positively associated with larger cIMT among subjects with high SDMA levels [>66th: 0.82 (95%-CI 0.80; 0.85 mm]. High SDMA levels were related to a higher odds ratio (OR of increased cIMT [OR 1.39 (95%-CI 1.08; 1.79]. Furthermore, ARG was positively associated with atherosclerotic plaques [OR 1.41 (95%-CI 1.07; 1.85]. No relation was found for ADMA and atherosclerosis.In conclusion, the hypothesis of a positive association between SDMA with an increased cIMT was confirmed. Unexpectedly, ARG was positively related to atherosclerotic plaque. In view of these inconsistent findings, the impact of ARG derivatives as atherosclerotic biomarkers deserves further research.

  20. 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.

  1. 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.

  2. 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...

  3. 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)

  4. 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...

  5. 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...

  6. 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.

  7. Dimethylarginine Dimethylaminohydrolase/Nitric Oxide Synthase Pathway in Liver and Kidney: Protective Effect of Cyanidin 3-O-β-D-Glucoside on Ochratoxin-A Toxicity

    Directory of Open Access Journals (Sweden)

    Rosaria Acquaviva

    2012-05-01

    Full Text Available The aim of the present study was to evaluate the effect of long-term cyanidin 3-O-β-D-glucoside (C3G and/or Ochratoxin A (OTA-exposure on dimethylarginine dimethylamino hydrolase/nitric oxide synthase (DDAH/NOS pathway in rats. The experiments were performed in rats supplemented with C3G (1 g/kg feed, OTA (200 ppb, and OTA + C3G. After 4 weeks of daily treatment, liver and kidneys were processed for eNOS, iNOS and DDAH-1 Western blotting, nitrite levels evaluation and DDAH activity determination. Results show that OTA is able to induce iNOS both in kidney and liver, whereas OTA is able to induce eNOS and DDAH-1 overexpression and DDAH activation only in kidney, resulting in increased nitrite levels. In kidney of OTA + C3G fed rats, iNOS, eNOS and DDAH-1 expression were less pronounced compared with those observed in the OTA-treated group. Coherent with the decreased iNOS, eNOS and DDAH-1 expression a decrease in nitrite levels and DDAH activity was observed in the OTA + C3G group. Results demonstrate that C3G is able to counteract the deleterious effects of chronic consumption of OTA and also suggest a possible involvement of iNOS-eNOS-DDAH impairment in OTA nephrocarcinogenity.

  8. 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.

  9. 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.

  10. 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…

  11. 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....

  12. Early Stage of Hypertensive Retinopathy; Is It Really Important?

    Directory of Open Access Journals (Sweden)

    Murat KARAMAN

    2014-09-01

    Full Text Available OBJECTIVE: To investigate the relationship between early stage hypertensive retinopathy (HTRP and endothelial dysfunction (ED in atherogenesis. MATERIAL and METHODS: A total of 99 subjects consisting of 73 patients diagnosed with Essential Hypertension (HT and 26 healthy subjects were included to the study. Flow mediated dilatation (FMD was performed to detect ED. Asymmetric dimethylarginine-ADMA was measured as a marker of ED and the hsCRP and sTWEAK levels were measured for microvascular inflammation. All patients were screened for retinopathy. RESULTS: The mean blood pressure of the hypertensive patients and the control subjects was 140.1±13.7/86.1±10.7 and 107.12±10.0/65.38±10.2 respectively. HTRP was positive in 60.3% (n=44 and negative in 39.7% (n=29 of the patients with hypertension. There was grade 1 retinopathy in 52.1% and grade 2 retinopathy in 8.2% of hypertensive patients. The hsCRP, sTWEAK and ADMA levels were significantly higher in hypertensive patients than in the control group (respectively, p=0,011, p=0,001, p=0,001. FMD levels were lower in the hypertensive group, as expected. FMD levels were lower in the retinopathy group when the hypertensive group with and without retinopathy and the control group compared. hsCRP, sTWEAK and ADMA levels were significantly higher in subjects with retinopathy. hsCRP, sTWEAK and ADMA levels were also significantly higher in subjects with retinopathy (p=0.039, p=0.001, p=0.001. CONCLUSION: ED is thought to play a role in HT etiology and is also important in the development of HT complications. It would be appropriate to evaluate hypertensive patients more carefully and perform the necessary laboratory tests to detect ED so that the proper treatment can be started (ACEI, exercise, lifestyle changes.

  13. Brain-natriuretic peptide and cyclic guanosine monophosphate as biomarkers of myxomatous mitral valve disease in dogs

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Falk, Bo Torkel; Teerlink, Tom;

    2011-01-01

    Elevations in the plasma concentrations of natriuretic peptides correlate with increased severity of myxomatous mitral valve disease (MMVD) in dogs. This study correlates the severity of MMVD with the plasma concentrations of the biomarkers N-terminal fragment of the pro-brain-natriuretic peptide...... (NT-proBNP) and its second messenger, cyclic guanosine monophosphate (cGMP). Furthermore, the l-arginine:asymmetric dimethylarginine (ADMA) ratio was measured as an index of nitric oxide availability. The study included 75 dogs sub-divided into five groups based on severity of MMVD as assessed...... by clinical examination and echocardiography. Plasma NT-proBNP and cGMP concentrations increased with increasing valve dysfunction and were significantly elevated in dogs with heart failure. The cGMP:NT-proBNP ratio decreased significantly in dogs with heart failure, suggesting the development of natriuretic...

  14. 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...

  15. 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...

  16. 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.

  17. 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.

  18. 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.

  19. Protein arginine methyltransferase and the related diseases%蛋白质精氨酸甲基转移酶与相关疾病

    Institute of Scientific and Technical Information of China (English)

    罗举

    2011-01-01

    The family of protein arginine methyltransferases ( PRMTs) , which selectively methylates the arginine residues, is involved in many important cellular processes like DNA damage repair, RNA processing, transcription regulation, and signal transduction. PRMTs are also the major source for asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor. Many studies reveal that PRMTs are closely related to cardiovascular diseases, respiratory diseases, cancer, infections, and autoimmune diseases.%蛋白质精氨酸甲基转移酶家族(protein arginine methyltransferase,PRMTs)催化精氨酸残基甲基化,参与许多重要的细胞过程,包括DNA修复、RNA加工、转录调控和信号转导.此外,PRMTs还是内源性一氧化氮合酶抑制物非对称性二甲基精氨酸(asymmetric dimethylarginine,ADMA)的重要来源.大量研究证实,PRMTs与心血管疾病、呼吸系统疾病、肿瘤、病毒感染、自身免疫性疾病密切相关.

  20. 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.

  1. 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...

  2. 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...

  3. 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.

  4. 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...

  5. 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.

  6. 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

  7. 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...

  8. 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...

  9. Dysfunction of endothelial NO system originated from homocysteine-induced aberrant methylation pattern in promoter region of DDAH2 gene

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-ge; LIU Jun-xu; LI Zhu-hua; WANG Li-zhen; JIANG Yi-deng; WANG Shu-ren

    2007-01-01

    Background Hyperhomocysteinemia (HHcy)-mediated dysfunction of endothelial NO system is an important mechanism for atherosclerotic pathogenesis.Dimethylarginine dimethylaminohydrolase (DDAH) is the key enzyme for degrading asymmetric dimethylarginine (ADMA),which is an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS).This study was designed to investigate whether the dysfunction of endothelial NO system originates from HHcy-mediated aberrant methylation modification in promotor region of DDAH2 gene.Methods Human umbilical vein endothelial cells (HUVECs) were cultured to the third generation and treated with homocysteine (Hcy) at different concentrations (0,10,30,100,and 300 μmol/L) for 72 hours.The methylation pattern in promoter region CpG island of DDAH2 gene was analyzed by nested methylation-specific PCR (nMSP).The mRNA expression of eNOS gene and DDAH2 gene was detected by semi-quantitative RT-PCR.The activity of DDAH2 and eNOS in cells,and the concentrations of ADMA and NO in culture medium were assayed respectively.Results Mild increased concentration of Hcy (10 and 30 μmol/L) induced hypomethylation,while high concentration of Hcy (100 and 300 μmol/L) induced hypermethylation in the promoter CpG island of DDAH2 gene.The mRNA expression of DDAH2 increased in mild enhanced concentration of Hcy,and decreased in high concentration of Hcy correspondingly.The inhibition of DDAH2 activity,the increase of ADMA concentration,the reduction of eNOS activity and the decrease of NO production were all consistently relevant to the alteration of Hcy concentration Conclusion The increased concentration of Hcy induced aberrant methylation pattern in promotor region of DDAH2 gene and the successive alterations in DDAH/ADMA/NOS/NO pathway,which showed highly relevant and dose-effect relationship.The results suggested that the dysfunction of endothelial NO system induced by HHcy could be partially originated from Hcy-mediated aberrant methylation in

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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...

  15. 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.

  16. Effect of the transdermal low-level laser therapy on endothelial function.

    Science.gov (United States)

    Szymczyszyn, Alicja; Doroszko, Adrian; Szahidewicz-Krupska, Ewa; Rola, Piotr; Gutherc, Radosław; Jasiczek, Jakub; Mazur, Grzegorz; Derkacz, Arkadiusz

    2016-09-01

    The effect of low-level laser therapy (LLLT) on the cardiovascular system is not fully established. Since the endothelium is an important endocrine element, establishing the mechanisms of LLLT action is an important issue.The aim of the study was to evaluate the effect of transdermal LLLT on endothelial function.In this study, healthy volunteers (n = 40, age = 20-40 years) were enrolled. N = 30 (14 female, 16 male, mean age 30 ± 5 years) constituted the laser-irradiated group (LG). The remaining 10 subjects (6 women, 4 men, mean age 28 ± 5 years) constituted the control group (CG). Participants were subjected to LLLT once a day for three consecutive days. Blood for biochemical assessments was drawn before the first irradiation and 24 h after the last session. In the LG, transdermal illumination of radial artery was conducted (a semiconductor laser λ = 808 nm, irradiation 50 mW, energy density 1.6 W/cm(2) and a dose 20 J/day, a total dose of 60 J). Biochemical parameters (reflecting angiogenesis: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiostatin; antioxidative status: glutathione (GSH) and the nitric oxide metabolic pathway: symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA) and L-arginine) were assessed. In the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation. PMID:27299570

  17. Impaired Fasting Glucose and Diabetes as Predictors for Radial Artery Calcification in End Stage Renal Disease Patients

    Directory of Open Access Journals (Sweden)

    Katarzyna Janda

    2013-01-01

    Full Text Available Objective. The objective of the study was to assess the relationship between selected clinical and biochemical parameters of end stage renal disease (ESRD patients and arterial calcification. Materials and Methods. The study comprised 59 stage 5 chronic kidney disease patients (36 hemodialyzed and 23 predialysis. The examined parameters included common carotid artery intima-media thickness (CCA-IMT, BMI, incidence of diabetes and impaired fasting glucose (IFG, dyslipidemia, hypertension, and 3-year mortality. Plasma levels asymmetric dimethylarginine (ADMA, osteopontin (OPN, osteoprotegerin (OPG, and osteocalcin (OC were also measured. Fragments of radial artery obtained during creation of hemodialysis access were stained for calcifications using von Kossa method and alizarin red. Results. Calcification of radial artery was significantly associated with higher prevalence of IFG and diabetes (P=0.0004 and older age (P=0.003, as well as higher OPG (P=0.014 and ADMA concentrations (P=0.022. Fasting glucose >5.6 mmol/l (IFG and diabetes significantly predicted vascular calcification in multiple logistic regression. The calcification was also associated with higher CCA-IMT (P=0.006 and mortality (P=0.004; OR for death 5.39 [1.20–24.1] after adjustment for dialysis status and age. Conclusion. Combination of renal insufficiency and hyperglycemic conditions exerts a synergistic effect on vascular calcification and increases the risk of death.

  18. Serum metabolomic profiles from patients with acute kidney injury: a pilot study.

    Science.gov (United States)

    Sun, Jinchun; Shannon, Melissa; Ando, Yosuke; Schnackenberg, Laura K; Khan, Nasim A; Portilla, Didier; Beger, Richard D

    2012-04-15

    Low sensitivity of current clinical markers (serum creatinine and blood urea nitrogen (BUN)) in early stages of the development of acute kidney injury (AKI) limits their utility. Rapid LC/MS-based metabolic profiling of serum demonstrated in a pilot study that metabolomics could provide novel indicators of AKI. Metabolic profiles of serum samples from seventeen hospitalized patients with newly diagnosed AKI were compared with the profiles of serum from age-matched subjects with normal kidney function. Increases in acylcarnitines and amino acids (methionine, homocysteine, pyroglutamate, asymmetric dimethylarginine (ADMA), and phenylalanine) and a reduction in serum levels of arginine and several lysophosphatidyl cholines were observed in patients with AKI compared to healthy subjects. Increases in homocysteine, ADMA and pyroglutamate have been recognized as biomarkers of cardiovascular and renal disease, and acylcarnitines represent biomarkers of defective fatty acid oxidation. The results of this pilot study demonstrate the utility of metabolomics in the discovery of novel serum biomarkers that can facilitate the diagnosis and determine prognosis of AKI in hospitalized patients.

  19. The effects of acute intermittent hypoxia on cardiovascular parameters in normotensive and chronic hypobaric hypoxia-induced hypertensive rabbits.

    Science.gov (United States)

    Yaman, Muhittin O; Guner, Ibrahim; Uzun, Hafize; Sahin, Gulderen; Yelmen, Nermin

    2014-01-01

    The effects of both chronic hypoxia and acute intermittent hypoxia (AIH) on cardiovascular system are unclear. We designed this study to develop a rabbit model of hypertension by exposure to chronic hypobaric hypoxia (CHH) and to investigate the effects of AIH on hypertensive rabbits. Present study was performed in 13 albino rabbits that divided into CHH and control groups. To develop hypertension, the rabbits were placed in a hypobaric chamber (390 mmHg; 22 hours/day, 30 days). Afterwards, AIH protocol was applied (8% FIO2 (Fraction of Inspired Oxygen) 1 min + 5 min normoxia, 20 cycles, 2 hours) to rabbits anesthetized with urethane and alpha-chloralose. Mean arterial pressure (MAP), heart rate (HR) and hematocrit values have been determined. Also asymmetric dimethylarginine (ADMA), endothelial nitric oxide synthase (eNOS), endothelin-1 and norepinephrine values have been analyzed in blood. We developed a model of hypertension in rabbits via exposure to severe CHH and we believe that ADMA is an important parameter in the development and permanence of CHH-induced hypertension. The main finding of this sudy was the depressor effect of AIH on blood pressure and heart rate in CHH- induced hypertension model. Finally, we believe that AIH protocol may be applicable for prevention and treatment of hypertension if properly developed. PMID:24448370

  20. Associations of functional alanine-glyoxylate aminotransferase 2 gene variants with atrial fibrillation and ischemic stroke.

    Science.gov (United States)

    Seppälä, Ilkka; Kleber, Marcus E; Bevan, Steve; Lyytikäinen, Leo-Pekka; Oksala, Niku; Hernesniemi, Jussi A; Mäkelä, Kari-Matti; Rothwell, Peter M; Sudlow, Cathie; Dichgans, Martin; Mononen, Nina; Vlachopoulou, Efthymia; Sinisalo, Juha; Delgado, Graciela E; Laaksonen, Reijo; Koskinen, Tuomas; Scharnagl, Hubert; Kähönen, Mika; Markus, Hugh S; März, Winfried; Lehtimäki, Terho

    2016-01-01

    Asymmetric and symmetric dimethylarginines (ADMA and SDMA) impair nitric oxide bioavailability and have been implicated in the pathogenesis of atrial fibrillation (AF). Alanine-glyoxylate aminotransferase 2 (AGXT2) is the only enzyme capable of metabolizing both of the dimethylarginines. We hypothesized that two functional AGXT2 missense variants (rs37369, V140I; rs16899974, V498L) are associated with AF and its cardioembolic complications. Association analyses were conducted using 1,834 individulas with AF and 7,159 unaffected individuals from two coronary angiography cohorts and a cohort comprising patients undergoing clinical exercise testing. In coronary angiography patients without structural heart disease, the minor A allele of rs16899974 was associated with any AF (OR = 2.07, 95% CI 1.59-2.68), and with paroxysmal AF (OR = 1.98, 95% CI 1.44-2.74) and chronic AF (OR = 2.03, 95% CI 1.35-3.06) separately. We could not replicate the association with AF in the other two cohorts. However, the A allele of rs16899974 was nominally associated with ischemic stroke risk in the meta-analysis of WTCCC2 ischemic stroke cohorts (3,548 cases, 5,972 controls) and with earlier onset of first-ever ischemic stroke (360 cases) in the cohort of clinical exercise test patients. In conclusion, AGXT2 variations may be involved in the pathogenesis of AF and its age-related thromboembolic complications. PMID:26984639

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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 ...

  8. 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.

  9. 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.

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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....

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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 ...

  2. Cardiovascular involvement in psoriatic arthritis

    Directory of Open Access Journals (Sweden)

    V. De Gennaro Colonna

    2011-11-01

    Full Text Available Psoriasis is a chronic, genetically determined and immunomediated inflammatory skin disease that affects 2-3% of the Caucasian population. A considerable proportion of these patients develop a form of inflammatory arthritis known as psoriatic arthritis (PsA, although the prevalence of this has not been well defined. Patients with PsA have a higher mortality rate than the general population and the risk of mortality is related to disease severity at the time of presentation. Endothelial dysfunction and early atherosclerosis have been found in patients with PsA without any cardiovascular disease (CVD risk factors, and experts believe that CVD is one of the leading causes of death, as it is in patients with rheumatoid arthritis (RA. Various disease-related mechanisms may be involved in the development of premature vascular damage in both cases, including an increased synthesis of proinflammatory mediators (such as cytokines, chemokines and adhesion molecules, autoantibodies against endothelial cell components, perturbations in T-cell subsets, genetic polymorphisms, hyperhomocysteinemia, oxidative stress, abnormal vascular repair, and iatrogenic factors. In a recent study of 22 patients with PsA without any signs of CVD, we found that the plasma concentration of asymmetric dimethylarginine (ADMA levels were significantly high and coronary flow reserve (CFR was significantly reduced. Moreover, there was a significant correlation between CFR and plasma ADMA levels in the PsA group. The significant correlation between the reduced CRF and increased ADMA levels suggests that, like patients with early RA, PsA patients suffer from endothelial dysfunction and impaired coronary microcirculation. Active PsA is a risk factor for CVD, and so PsA patients should be screened for subclinical forms of the disease and its risk factors, and an early treatment approach should be adopted.

  3. Nitric Oxide Bioavailability and Adiponectin Production in Chronic Systolic Heart Failure: Relation to Severity of Cardiac Dysfunction

    Science.gov (United States)

    Tang, W.H. Wilson; Shrestha, Kevin; Tong, Wilson; Wang, Zeneng; Troughton, Richard W.; Borowski, Allen G.; Klein, Allan L.; Hazen, Stanley L.

    2013-01-01

    Adiponectin is an anti-inflammatory, anti-atherogenic adipokine elevated in heart failure (HF) that may protect against endothelial dysfunction by influencing underlying nitric oxide bioavailablity. In this study, we examine the relationship between plasma adiponectin levels and measures of nitric oxide bioavailability and myocardial performance in patients with chronic systolic HF. In 139 ambulatory patients with stable, chronic systolic HF (left ventricular [LV] ejection fraction ≤40%, New York Heart Association [NYHA] class I to IV), we measured plasma levels of adiponectin, asymmetric dimethylarginine (ADMA) and global arginine bioavailability (GABR), and performed comprehensive echocardiography with assessment of cardiac structure and performance. Adverse events (all-cause mortality or cardiac transplantation) were prospectively tracked for a median of 39 months. Plasma adiponectin levels directly correlated with plasma ADMA levels (Spearman’s r=0.41, p<0.001) and NT-proBNP levels (r=0.55, p<0.001), inversely correlated with GABR (r= −0.39, p<0.001), and were not associated with hsCRP (p=0.81) or MPO (p=0.07). Interestingly, increased plasma adiponectin levels remained positively correlated with plasma ADMA levels only in patients with elevated NT-proBNP levels (r= 0.33, p=0.009). Higher plasma adiponectin levels were associated with worse LV diastolic dysfunction (rank sums p=0.002), RV systolic dysfunction (rank sums p=0.002), and RV diastolic dysfunction (rank sums p=0.011), but not after adjustment for plasma ADMA and NT-proBNP levels. Plasma adiponectin levels predicted increased risk of adverse clinical events (HR [95% CI]: 1.45 [1.02–2.07], p=0.038) but not after adjustment for plasma ADMA and NT-proBNP levels, or echocardiographic indices of diastolic or RV systolic dysfunction. In patients with chronic systolic HF, adiponectin production is more closely linked with nitric oxide bioavailability than inflammation, and appears to be more robust

  4. 胰岛素样生长因子-1对高胆固醇血症患者内皮的保护作用及机制%Protective effect of insulin-like growth factor-1 on vascular endothelial function in hypercholesterolemia and the underlying mechanism

    Institute of Scientific and Technical Information of China (English)

    吉绍葵; 马琦琳; 罗秀菊; 彭军

    2013-01-01

    目的:探讨血清胰岛素样生长因子-1 (insulin-like growth factor-1,IGF-1)对高胆固醇血症血管内皮的保护作用及机制.方法:观察高胆固醇血症患者和正常对照(各25例)肱动脉血流介导的血管舒张功能(flow-mediated arterial diastolic function,FMD),并检测血清中IGF-1、非对称二甲基精氨酸(asymmetric dimethylarginine,ADMA)、一氧化氮合酶(nitric oxide synthase,NOS)以及一氧化氮(NO)水平;将培养的人脐静脉内皮细胞分为3组:正常对照组、氧化型低密度脂蛋白(oxidized low-density lipoprotein,ox-LDL)损伤组和IGF-1干预组,培养24 h后,检测各组细胞培养液中ADMA,NOS,NO水平,细胞裂解液中二甲基精氨酸二甲胺水解酶(dimethylarginine dimethylamine hydrolase,DDAH)活性,并进行β-半乳糖苷酶染色,计算细胞衰老率.结果:临床实验中,高胆固醇血症患者FMD显著下降;伴随血清IGF-1,NOS以及NO水平的下降,ADMA水平升高.多元线性回归分析显示IGF-1与FMD呈正相关,ADMA与FMD呈负相关.细胞实验中,ox-LDL处理24 h后,细胞裂解液DDAH活性下降;伴随上清液中ADMA水平升高,NOS和NO水平下降和细胞衰老率增加,给予IGF-1干预能部分逆转上述作用.结论:血液中IGF-1水平下降可能是高胆固醇血症患者血管内皮舒张功能受损的重要原因之一;IGF-1具有抗内皮细胞衰老作用,其机制可能涉及对DDAH/ADMA途径的调节.%Objective: To investigate the relationship between insulin-like growth factor-1 (IGF-l) in the serum and the vascular endothelial function in patients with hypercholesterolemia and the underlying mechanism. Methods: We examined the flow-mediated arterial diastolic function (FMD), the levels of IGF-1, asymmetric dimethylarginine (ADMA), NO, and the activity of nitric oxide synthase (NOS) in the serum from 25 patients with hypercholesterolemia and from healthy controls. An endothelial cell injury model was established by incubation of the

  5. [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.

  6. 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....

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Endothelial dysfunction and brachial intima-media thickness: long term cardiovascular risk with claudication related to peripheral arterial disease: a prospective analysis.

    Directory of Open Access Journals (Sweden)

    Franz Hafner

    Full Text Available OBJECTIVE: Endothelial dysfunction plays a key role in the development, progression, and clinical manifestation of atherosclerosis, and in symptomatic peripheral arterial disease, endothelial dysfunction and enlarged intima-media thickness might be associated with increased cardiovascular risk. Flow-mediated dilatation and serologic parameters are used to evaluate individual endothelial function. Brachial intima-media thickness, a less recognized parameter of cardiovascular risk, is independently associated with coronary artery disease. The aim of this study was to evaluate the prognostic value of ultrasound and serologic parameters of endothelial function in relation to cardiovascular mortality in peripheral arterial disease. DESIGN: monocentric, prospective cohort study. METHODS: Flow mediated dilatation and brachial intima-media thickness were assessed in 184 (124 male patients with peripheral arterial disease (Rutherford stages 2-3. Serologic parameters of endothelial function included asymmetric dimethylarginine (ADMA, symmetric dimethylarginine (SDMA, and L-homoarginine. Cardiovascular events were recorded during a follow-up of 99.1±11.1 months. Subjects who died of noncardiovascular causes were excluded from further analysis. RESULTS: Eighty-two patients (44.6% died during follow-up after a mean duration of 49.7±28.3 months. There were 49 cardiovascular deaths (59.8% and 33 other deaths (40.2%. Flow mediated dilatation was associated with cardiovascular death [1.17% (0.0, 4.3 vs. 4.1% (1.2, 6.4, p<0.001]. Intima-media thickness was greater in patients who succumbed to cardiovascular disease [0.37 mm (0.30, 0.41] than in survivors [0.21 mm (0.15, 0.38, p<0.001]. Brachial intima-media thickness above 0.345 mm was most predictive of cardiovascular death, with sensitivity and specificity values of 0.714 and 0.657, respectively (p<0.001. Furthermore, ADMA levels above 0.745 µmol/l and SDMA levels above 0.825 µmol/l were significantly

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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

  1. 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....

  2. 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.

  3. 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).

  4. 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…

  5. 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

  6. 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

  7. 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...

  8. 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...

  9. 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

  10. 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....

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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

  2. 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...

  3. 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...

  4. 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...

  5. 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."

  6. 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,...

  7. 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.

  8. 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 ...

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. 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...

  15. 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.

  16. 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.

  17. Alanine-Glyoxylate Aminotransferase-2 Metabolizes Endogenous Methylarginines, Regulates NO, and Controls Blood Pressure

    NARCIS (Netherlands)

    Caplin, Ben; Wang, Zhen; Slaviero, Anna; Tomlinson, James; Dowsett, Laura; Delahaye, Mathew; Salama, Alan; Wheeler, David C.; Leiper, James

    2012-01-01

    Objective-Asymmetric dimethylarginine is an endogenous inhibitor of NO synthesis that may mediate cardiovascular disease. Alanine-glyoxylate aminotransferase-2 (AGXT2) has been proposed to degrade asymmetric dimethylarginine. We investigated the significance of AGXT2 in methylarginine metabolism in

  18. Interactions among Vascular-Tone Modulators Contribute to High Altitude Pulmonary Edema and Augmented Vasoreactivity in Highlanders

    Science.gov (United States)

    Ali, Zahara; Mishra, Aastha; Kumar, Rahul; Alam, Perwez; Pandey, Priyanka; Ram, Rekhbala; Thinlas, Tashi; Mohammad, Ghulam; Pasha, M. A. Qadar

    2012-01-01

    Background The interactions among various biomarkers remained unexplored under the stressful environment of high-altitude. Present study evaluated interactions among biomarkers to study susceptibility for high altitude pulmonary edema (HAPE) in HAPE-patients (HAPE-p) and adaptation in highland natives (HLs); both in comparison to HAPE-free sojourners (HAPE-f). Methodology/Principal Findings All the subjects were recruited at 3500 m. We measured clinical parameters, biochemical levels in plasma and gene expression using RNA from blood; analyzed various correlations between and among the clinical parameters, especially arterial oxygen saturation (SaO2) and mean arterial pressure (MAP) and biochemical parameters like, asymmetric dimethylarginine (ADMA), serotonin (5-HT), 8-iso-prostaglandin F2α (8-isoPGF2α), endothelin-1 (ET-1), plasma renin activity (PRA), plasma aldosterone concentration (PAC), superoxide dismutase (SOD) and nitric oxide (NO) in HAPE-p, HAPE-f and HLs. ADMA, 5-HT, 8-isoPGF2α, ET-1 levels, and PAC were significantly higher (p0.05) lower in HLs than HAPE-f. The expression of respective genes differed in the three groups. In the correlations, SaO2 inversely correlated with ADMA, 5-HT and 8-isoPGF2α and positively with SOD in HAPE-p (p≤0.009). MAP correlated positively with 5-HT and 8-isoPGF2α in HAPE-p and HLs (p≤0.004). A strong positive correlation was observed between ADMA and 5-HT, 5-HT and 8-isoPGF2α (p≤0.001), whereas inverse correlation of SOD with ET-1 in HAPE-p and HLs (p≤0.004), with 5-HT and 8-isoPGF2α in HAPE-p (p = 0.01) and with 5-HT in HLs (p = 0.05). Conclusions/Significance The interactions among these markers confer enhanced vascular activity in HLs and HAPE in sojourners. PMID:22984459

  19. Interrelationship of Multiple Endothelial Dysfunction Biomarkers with Chronic Kidney Disease.

    Directory of Open Access Journals (Sweden)

    Jing Chen

    Full Text Available The interrelationship of multiple endothelial biomarkers and chronic kidney disease (CKD has not been well studied. We measured asymmetric dimethylarginine (ADMA, L-arginine, soluble intercellular adhesion molecule-1 (sICAM-1, soluble vascular adhesion molecule-1 (sVCAM-1, soluble E-selectin (sE-selectin, von Willebrand factor (vWF, flow-mediated dilation (FMD, and nitroglycerin-induced dilation (NID in 201 patients with CKD and 201 community-based controls without CKD. Multivariable analyses were used to examine the interrelationship of endothelial biomarkers with CKD. The multivariable-adjusted medians (interquartile ranges were 0.54 (0.40, 0.75 in patients with CKD vs. 0.25 (0.22, 0.27 μmol /L in controls without CKD (p<0.0001 for group difference for ADMA; 67.0 (49.6, 86.7 vs. 31.0 (27.7, 34.2 μmol/L (p<0.0001 for L-arginine; 230.0 (171.6, 278.6 vs. 223.9 (178.0, 270.6 ng/mL (p=0.55 for sICAM-1; 981.7 (782.6, 1216.8 vs. 633.2 (507.8, 764.3 ng/mL (p<0.0001 for sVCAM-1; 47.9 (35.0, 62.5 vs. 37.0 (28.9, 48.0 ng/mL (p=0.01 for sE-selectin; 1320 (1044, 1664 vs. 1083 (756, 1359 mU/mL (p=0.008 for vWF; 5.74 (3.29, 8.72 vs. 8.80 (6.50, 11.39% (p=0.01 for FMD; and 15.2 (13.5, 16.9 vs. 19.1 (17.2, 21.0% (p=0.0002 for NID, respectively. In addition, the severity of CKD was positively associated with ADMA, L-arginine, sVCAM-1, sE-selectin, and vWF and inversely associated with FMD and NID. Furthermore, FMD and NID were significantly and inversely correlated with ADMA, L-arginine, sVCAM-1, sE-selectin, and vWF. In conclusion, these data indicate that multiple dysfunctions of the endothelium were present among patients with CKD. Interventional studies are warranted to test the effects of treatment of endothelial dysfunction on CKD.

  20. Effect of vitamin D on aortic remodeling in streptozotocin-induced diabetes

    Directory of Open Access Journals (Sweden)

    Salum Erik

    2012-07-01

    Full Text Available Abstract Background Diabetes mellitus is associated with micro- and macrovascular complications and increased cardiovascular risk. Elevated levels of serum asymmetric dimethylarginine (ADMA may be responsible for endothelial dysfunction associated with diabetes-induced vascular impairment. Vitamin D may have potential protective effects against arterial stiffening. This study aimed to examine both the effects of diabetes on the functional/structural properties of the aorta and the endothelial function and the effects of vitamin D supplementation. Methods Male Wistar rats (n = 30 were randomly assigned to control untreated, diabetic untreated, and diabetic + cholecalciferol groups. Diabetes was induced by intraperitoneal injection of streptozotocin, followed by oral administration of cholecalciferol (500 IU/kg for 10 weeks in the treatment group. Aortic pulse wave velocity (PWV was recorded over a mean arterial pressure (MAP range of 50 to 200 mmHg using a dual pressure sensor catheter. Intravenous infusion of phenylephrine and nitroglycerine was used to increase and decrease MAP, respectively. Serum 25-hydroxyvitamin D [25(OHD] levels were measured using a radioimmune assay. ADMA levels in serum were measured by enzyme-linked immunoassay. Aortic samples were collected for histomorphometrical analysis. Results PWV up to MAP 170 mmHg did not reveal any significant differences between all groups, but in diabetic rats, PWV was significantly elevated across MAP range between 170 and 200 mmHg. Isobaric PWV was similar between the treated and untreated diabetic groups, despite significant differences in the levels of serum 25(OHD (493 ± 125 nmol/L vs 108 ± 38 nmol/L, respectively. Serum levels of ADMA were similarly increased in the treated and untreated diabetic groups, compared to the control group. The concentration and integrity of the elastic lamellae in the medial layer of the aorta was impaired in untreated

  1. 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.

  2. Role of alpha-lipoic acid in the management of anemia in patients with chronic renal failure undergoing hemodialysis

    Directory of Open Access Journals (Sweden)

    El-Nakib GA

    2013-08-01

    Full Text Available Gehad A El-Nakib,1 Tarek M Mostafa,2 Tarek M Abbas,4 Mamdouh M El-Shishtawy,3 Mokhtar M Mabrouk,2 Mohammed A Sobh41Mansoura University Hospitals, Mansoura, Egypt; 2Faculty of Pharmacy, Tanta University, Tanta, Egypt; 3Faculty of Pharmacy, Mansoura University, Mansoura, Egypt; 4Urology and Nephrology Centre, Faculty of Medicine, Mansoura University, Mansoura, EgyptIntroduction: Anemia associated with chronic kidney disease is a serious complication necessitating expenditure of huge medical efforts and resources. This study investigates the role of alpha-lipoic acid (ALA in end stage renal disease patients undergoing hemodialysis. By the virtue of its antioxidative effects, ALA is expected to act as an erythropoietin (EPO adjuvant, and also has extended beneficial effects on endothelial dysfunction.Methods: Forty-four patients undergoing hemodialysis and receiving EPO were randomized into two groups: the first group received ALA 600 mg once daily for 3 months; while the other group represented the control group. Parameters measured at baseline and at end of study were hemoglobin, EPO doses, EPO resistance index (ERI, iron store indices, malondialdehyde, oxidized low-density lipoprotein (ox-LDL, interleukin-6 (IL-6, tumor necrosis factor-α (TNF-α, and asymmetric dimethylarginine (ADMA, as well as routine laboratory follow-up.Results: EPO doses and ERI were significantly decreased in the treatment group, while they did not change in the control group. Hemoglobin, iron store indices, malondialdehyde, oxidized ox-LDL, IL-6, TNF-α, and ADMA were similar in both treatment and control groups at baseline, and did not change by the end of study period. Likewise, routine laboratory measures were not affected by the treatment.Conclusion: ALA could be used in hemodialysis patients to reduce requirements for EPO. However, larger and longer term studies are required to clarify the exact role of ALA in hemodialysis as well as in pre-hemodialysis patients

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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....

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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...

  14. 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)

  15. Nuclear factor-kB dependent protein arginine methyltransferase%核因子kB依赖的蛋白质精氨酸甲基转移酶1

    Institute of Scientific and Technical Information of China (English)

    王翠莲; 楚东岭; 金发光

    2008-01-01

    Arginine methylation involves in manifold cellular processes like signaling, transcription regulation,chromatin remolding, and apoptosis with extensive biology function. During recent years, new members of the family of protein arginine methyltransferases have been increasing, by now there are eleven protein arginine methyltransferases. Protein arginine methyltransferases are classified into two groups. Type I protein arginine methyltransferases catalyze the formation of monomethylarginine and asymmetric dimethylarginine,type Ⅱ enzymes form monomethylarginine and symmetric dimethylarginine. Coactivator- associated arginine methyltransferasel is a nuclear faetor-kB(NF-kB) dependent transcriptional coactivator and functions as a promoter-specific regulator of NF-kB recruitment to chromatin. Coactivator-associated arginine methyltransferasel may activate NF-kB signal transduction pathway by enhancing NF-kB recruitment to cognate sites and initate transcriptional activation of a variety of proinflammatory and immunoregulation genes, which plays critical role in transcription regulation of immune and inflammatory reaction genes. Now it is generally accepted that lung is the major source of NO,plays an important role in NO metabolism,and acts as the major source of NOS inhibitor asymmetric dimethylarginine. Asymmetric dimethylarginine serves as false substrates and competitively inhibits NOS activity, blocking the formation of endogenous NO. As a major source of not only NO but also the NOS inhibitor asymmetric dimethylarginine, the lung likely plays a critical role in the important and delicate balance of arginine-methylarginine-NO.%精氨酸甲基化参与信号转导、转录调控、染色质重塑和凋亡等多种细胞事件具有广泛的生物学功能.近年来蛋白质精氨酸甲基转移酶家族的新成员日益增多,目前已知有11个人类蛋白质精氨酸甲基转移酶.蛋白质精氨酸甲基转移酶可分成两型,Ⅰ型蛋白质精氨酸甲

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.  ……

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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...

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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....

  12. 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....

  13. 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.

  14. 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.

  15. 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...

  16. 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

  17. 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

  18. 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 ...

  19. 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...

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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,

  6. NO synthesis from arginine is favored by α-linolenic acid in mice fed a high-fat diet.

    Science.gov (United States)

    Hermier, Dominique; Guelzim, Najoua; Martin, Pascal G P; Huneau, Jean-François; Mathé, Véronique; Quignard-Boulangé, Annie; Lasserre, Frédéric; Mariotti, François

    2016-09-01

    Alterations in NO availability and signaling play a pivotal role at early stages of the metabolic syndrome (MetSynd). We hypothesized that dietary α-linolenic acid (ALA, 18:3 n-3) favors NO availability by modulating amino acid metabolism, with a specific impact on the arginine-NO pathway. Mice were fed a hyperlipidic diet (285 g lipid/kg, 51.1 % energy), rich in either saturated fatty acids (SFA, provided by palm oil, PALM group) or ALA (provided by linseed oil, LIN group). We measured whole-body NO synthesis and systemic arginine hydrolysis with a tracer-based method, plasma concentration of related metabolites, and hepatic mRNA level of related enzymes, and the study was completed by a transcriptomic analysis in the liver. As expected with this model, hyperlipidic diets resulted in increased adiposity and glycemia after 5 weeks. As compared to PALM mice, LIN mice had a higher plasma nitrite and nitrate concentration, a higher whole-body conversion of arginine into NO vs urea, and a similar plasma concentration of asymmetric dimethylarginine (ADMA), despite a higher expression of the liver dimethylargininase-1. In LIN mice, there was a higher expression of genes involved in PPARα signaling, but a little impact on gene expression related to amino acids and arginine metabolism. This effect cannot be directly ascribed to changes in arginase activity in the liver or ADMA metabolism, nor to direct regulation of the related target genes. In conclusion, dietary ALA favors NO synthesis, which could contribute to rescue NO availability when jeopardized by the nutritional conditions in relation with the initiation of the MetSynd. PMID:27178023

  7. Postprandial Vascular Effects of VIAject Compared With Insulin Lispro and Regular Human Insulin in Patients With Type 2 Diabetes

    Science.gov (United States)

    Forst, Thomas; Pfützner, Andreas; Flacke, Frank; Krasner, Alan; Hohberg, Cloth; Tarakci, Eda; Pichotta, Philip; Forst, Senait; Steiner, Solomon

    2010-01-01

    OBJECTIVE Recent studies suggested an impact of prandial insulin delivery on postprandial regulation of tissue blood flow. This study compared the effect of VIAject with human regular insulin and insulin lispro on postprandial oxidative stress and endothelial function in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Fourteen patients (seven men; aged 61.5 ± 1.8 years; duration of diabetes 6.6 ± 4.6 years; A1C 7.2 ± 0.5% [mean ± SEM]) received a prandial injection of VIAject, human regular insulin, and insulin lispro. At baseline and after a standardized liquid meal test (Ensure Plus), the postprandial increases in asymmetric dimethylarginine (ADMA) and nitrotyrosine levels were investigated. In addition, the postprandial effects on microvascular blood flow, skin oxygenation, and vascular elasticity were measured. RESULTS Treatment with VIAject resulted in a significant reduction in the peak postprandial generation of ADMA compared with human insulin and insulin lispro (VIAject −27.3 ± 22.6, human insulin 97.7 ± 24.4, and insulin lispro 66.9 ± 33.9 nmol/l; P < 0.05, respectively). The postprandial increases in nitrotyrosine levels were significantly less after VIAject than after human regular insulin (VIAject −0.22 ± 0.17 vs. human insulin 0.25 ± 0.15 μg/ml; P < 0.05), whereas nitrotyrosine after insulin lispro was in between (insulin lispro 0.09 ± 0.07 μg/ml; NS). In parallel, earlier and more pronounced increases in microvascular blood flow and skin oxygenation were obtained after VIAject compared with those after human insulin or insulin lispro (P < 0.05, respectively). All insulin formulations resulted in comparable improvements in central arterial elasticity. CONCLUSIONS Treatment with VIAject reduced postprandial oxidative stress and improved endothelial function compared with human regular insulin or insulin lispro. PMID:19808913

  8. Nitric oxide synthase inhibition and oxidative stress in cardiovascular diseases: possible therapeutic targets?

    Science.gov (United States)

    Rochette, Luc; Lorin, Julie; Zeller, Marianne; Guilland, Jean-Claude; Lorgis, Luc; Cottin, Yves; Vergely, Catherine

    2013-12-01

    Nitric oxide (NO) is synthetized enzymatically from l-arginine (l-Arg) by three NO synthase isoforms, iNOS, eNOS and nNOS. The synthesis of NO is selectively inhibited by guanidino-substituted analogs of l-Arg or methylarginines such as asymmetric dimethylarginine (ADMA), which results from protein degradation in cells. Many disease states, including cardiovascular diseases and diabetes, are associated with increased plasma levels of ADMA. The N-terminal catalytic domain of these NOS isoforms binds the heme prosthetic group as well as the redox cofactor, tetrahydrobiopterin (BH(4)) associated with a regulatory protein, calmodulin (CaM). The enzymatic activity of NOS depends on substrate and cofactor availability. The importance of BH(4) as a critical regulator of eNOS function suggests that BH(4) may be a rational therapeutic target in vascular disease states. BH(4) oxidation appears to be a major contributor to vascular dysfunction associated with hypertension, ischemia/reperfusion injury, diabetes and other cardiovascular diseases as it leads to the increased formation of oxygen-derived radicals due to NOS uncoupling rather than NO. Accordingly, abnormalities in vascular NO production and transport result in endothelial dysfunction leading to various cardiovascular disorders. However, some disorders including a wide range of functions in the neuronal, immune and cardiovascular system were associated with the over-production of NO. Inhibition of the enzyme should be a useful approach to treat these pathologies. Therefore, it appears that both a lack and excess of NO production in diseases can have various important pathological implications. In this context, NOS modulators (exogenous and endogenous) and their therapeutic effects are discussed.

  9. Protective effects of Nigella sativa against hypertension-induced oxidative stress and cardiovascular dysfunction in rats

    Directory of Open Access Journals (Sweden)

    Nur Taşar

    2012-05-01

    Full Text Available We investigated the protective effect of Nigella sativa against oxidative injury in the heart and kidney tissues of rats with renovascular hypertension (RVH. RVH model was induced by placing a renal artery clip (2-kidney-1-clip, 2K1C in Wistar albino rats (n= 8, while sham rats (n= 8 had no clip placement. Starting on the 3rd week after the operation, rats received Nigella sativa (0.2 ml/kg/day, intraperitoneally or vehicle for the following 6 weeks. Blood pressures (BP were recorded at the beginning of the study and at the end of the 3rd and 9th weeks. Cardiac functions were assessed using transthoracic echocardiography before the rats were decapitated. Plasma samples were obtained to assay asymmetric dimethylarginine (ADMA, nitric oxide (NO, creatine kinase (CK and lactate dehydrogenase (LDH levels. Production of reactive oxidants was monitored by chemiluminescence (CL assay in the cardiac and renal tissues. Moreover oxidative injury was examined through malondialdehyde (MDA and glutathione (GSH levels and Na+,K+-ATPase activity in these tissues. 2K1C caused increased BP and left ventricular (LV dysfunction, while plasma ADMA, CK, and LDH levels were increased (p<0.05-0.001. Moreover, hypertension caused significant decreases in plasma NO levels, as well as in tissue Na+,K+-ATPase activities and GSH contents, while MDA levels in both tissues were increased (p<0.05-0.001. On the other hand, Nigella sativa treatment significantly reduced BP, attenuated oxidative injury and improved LV function. Nigella sativa protected against hypertension-induced tissue damage and improved cardiovascular function via its antioxidant and antihypertensive actions, suggesting a therapeutic potential of Nigella sativa in renovascular hypertension.

  10. Restoration of impaired nitric oxide production in MELAS syndrome with citrulline and arginine supplementation.

    Science.gov (United States)

    El-Hattab, Ayman W; Hsu, Jean W; Emrick, Lisa T; Wong, Lee-Jun C; Craigen, William J; Jahoor, Farook; Scaglia, Fernando

    2012-04-01

    Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is one of the most common mitochondrial disorders. Although the pathogenesis of stroke-like episodes remains unclear, it has been suggested that mitochondrial proliferation may result in endothelial dysfunction and decreased nitric oxide (NO) availability leading to cerebral ischemic events. This study aimed to assess NO production in subjects with MELAS syndrome and the effect of the NO precursors arginine and citrulline. Using stable isotope infusion techniques, we assessed arginine, citrulline, and NO metabolism in control subjects and subjects with MELAS syndrome before and after arginine or citrulline supplementation. The results showed that subjects with MELAS had lower NO synthesis rate associated with reduced citrulline flux, de novo arginine synthesis rate, and plasma arginine and citrulline concentrations, and higher plasma asymmetric dimethylarginine (ADMA) concentration and arginine clearance. We conclude that the observed impaired NO production is due to multiple factors including elevated ADMA, higher arginine clearance, and, most importantly, decreased de novo arginine synthesis secondary to decreased citrulline availability. Arginine and, to a greater extent, citrulline supplementation increased the de novo arginine synthesis rate, the plasma concentrations and flux of arginine and citrulline, and NO production. De novo arginine synthesis increased markedly with citrulline supplementation, explaining the superior efficacy of citrulline in increasing NO production. The improvement in NO production with arginine or citrulline supplementation supports their use in MELAS and suggests that citrulline may have a better therapeutic effect than arginine. These findings can have a broader relevance for other disorders marked by perturbations in NO metabolism.

  11. Mice lacking thyroid hormone receptor Beta show enhanced apoptosis and delayed liver commitment for proliferation after partial hepatectomy.

    Directory of Open Access Journals (Sweden)

    Raquel López-Fontal

    Full Text Available BACKGROUND: The role of thyroid hormones and their receptors (TR during liver regeneration after partial hepatectomy (PH was studied using genetic and pharmacologic approaches. Roles in liver regeneration have been suggested for T3, but there is no clear evidence distinguishing the contribution of increased amounts of T3 from the modulation by unoccupied TRs. METHODOLOGY/PRINCIPAL FINDINGS: Mice lacking TRalpha1/TRbeta or TRbeta alone fully regenerated liver mass after PH, but showed delayed commitment to the initial round of hepatocyte proliferation and transient but intense apoptosis at 48h post-PH, affecting approximately 30% of the remaining hepatocytes. Pharmacologically induced hypothyroidism yielded similar results. Loss of TR activity was associated with enhanced nitrosative stress in the liver remnant, due to an increase in the activity of the nitric oxide synthase (NOS 2 and 3, caused by a transient decrease in the concentration of asymmetric dimethylarginine (ADMA, a potent NOS inhibitor. This decrease in the ADMA levels was due to the presence of a higher activity of dimethylarginineaminohydrolase-1 (DDAH-1 in the regenerating liver of animals lacking TRalpha1/TRbeta or TRbeta. DDAH-1 expression and activity was paralleled by the activity of FXR, a transcription factor involved in liver regeneration and up-regulated in the absence of TR. CONCLUSIONS/SIGNIFICANCE: We report that TRs are not required for liver regeneration; however, hypothyroid mice and TRbeta- or TRalpha1/TRbeta-deficient mice exhibit a delay in the restoration of liver mass, suggesting a specific role for TRbeta in liver regeneration. Altered regenerative responses are related with a delay in the expression of cyclins D1 and E, and the occurrence of liver apoptosis in the absence of activated TRbeta that can be prevented by administration of NOS inhibitors. Taken together, these results indicate that TRbeta contributes significantly to the rapid initial round of

  12. Increased p-cresyl sulfate level is independently associated with poor outcomes in patients with heart failure.

    Science.gov (United States)

    Wang, Chao-Hung; Cheng, Mei-Ling; Liu, Min-Hui; Shiao, Ming-Shi; Hsu, Kuang-Hung; Huang, Yu-Yen; Lin, Cheng-Cheng; Lin, Jui-Fen

    2016-07-01

    Amino acid-derived metabolites, including protein-bound uremic toxins, may have prognostic value for patients with heart failure (HF). The aim of this study was to investigate whether p-cresyl sulfate (PCS), indoxyl sulfate (IS), and arginine metabolites provided prognostic values in addition to the traditional biomarker, B-type natriuretic peptide (BNP), in patients with HF. Chromatography mass spectrometry was performed to measure tyrosine, tryptophan, arginine, PCS, IS, and asymmetric (ADMA) and symmetric dimethylarginine (SDMA) in the plasma from 51 normal controls and 136 HF patients. Compared to the normal controls, PCS levels significantly increased in HF patients (p = 0.003). During the follow-up (2.3 ± 1.1 years), 35 (25.7 %) patients experienced a composite event of death or HF-related re-hospitalization. In univariable analysis, PCS, estimated glomerular filtration rate (eGFR), BNP, DMA/arginine ratio, and ADMA/arginine ratio were associated with a higher rate of composite events. In the multivariable analysis, PCS was the only independent predictor of composite events [hazard ratio (HR) 1.06 (per 10 μM), 95 % confidence interval (CI) 1.01-1.11, p = 0.02]. Kaplan-Meier curves showed that a PCS level of ≥50 μM was significantly associated with a higher composite event rate than those with a PCS level of <50 μM (Log rank = 5.11, p = 0.024; HR 2.13, 95 % CI 1.09-4.16, p = 0.02). In conclusion, among protein-bound uremic toxins, eGFR, and DMA metabolites, increased PCS is the only independent predictor of HF-related events in patients with HF. A combination of PCS and BNP should better risk-stratify patients with HF.

  13. 阴沟肠杆菌B8拮抗活性基因'admA'及上游调控序列的克隆与功能鉴定%Cloning and function identification of gene 'admA' and up-stream regulatory sequence related to antagonistic activity of Enterobacter cloacae B8

    Institute of Scientific and Technical Information of China (English)

    朱军莉; 李德葆; 余旭平

    2012-01-01

    为了阐明水稻白叶枯病拮抗菌阴沟肠杆菌B8 的作用机理,文章采用转座子标签法和染色体步移技术克隆到突变株B8B 中Tn5 插入位点周边拮抗活性相关片段,并通过基因敲除验证了获得的拮抗相关片段-admA'上游调控序列的功能.以转座子中Kan 抗性基因为标签,克隆了B8B菌株中Tn5 插入位点左侧2 608 bp 序列,经两次染色体步移得到Tn5 插入位点右侧的2 354 bp 序列.序列拼接后获得B8 菌株拮抗相关序列4 611 bp 的Bcontig.生物信息学分析显示该序列含有7 个ORF,分别对应于3-磷酸甘油醛脱氢酶(GADPH)基因的部分编码区、2 个LysR 家族转录调控因子、弧菌假设蛋白VSWAT3-20465 及成团泛菌(Pantoea agglomerans) andrimid 生物合成基因簇的admA、admB 和部分admC 基因序列.B8B 菌株Tn5 插入分别位于同源于弧菌假设蛋白的anrPORF 及‘admA'基因上游200 bp 和894 bp 处.通过同源重组技术,借助敲除质粒pMB-BG,获得拮抗活性消失的突变株B-1 和B-3.结果表明B8B 突变株中Tn5 的插入可能影响了anrP 蛋白的转录和表达,进而调控拮抗物质编码基因簇的生物合成.B8 菌株中拮抗物质相关基因是类似于andrimid 生物合成基因簇的基因家族,其上游调控区对该抗生素的生物合成具有重要的作用.%To reveal the antagonistic mechanism of B8 strain to Xanthomonas oryzae pv. Oryzae, transposon tagging method and chromosome walking were deployed to clone antagonistic related fragments around Tn5 insertion site in the mutant strain B8B. The function of up-stream regulatory sequence of gene 'admA' involved in the antagonistic activity was further identified by gene knocking out technique. An antagonistic related left fragment of Tn5 insertion site, 2 608 bp in length, was obtained by tagging with Kan resistance gene of Tn5. A 2 354 bp right fragment of Tn5 insertion site was amplified with 2 rounds of chromosome walking. The length of the B

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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 ...

  4. 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.

  5. 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.

  6. 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)

  7. 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 ...

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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).

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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...

  3. 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...

  4. 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

  5. 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...

  6. 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

  7. 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,...

  8. 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...

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Effects of chronic oral L-arginine administration on the L-arginine/NO pathway in patients with peripheral arterial occlusive disease or coronary artery disease: L-Arginine prevents renal loss of nitrite, the major NO reservoir.

    Science.gov (United States)

    Schneider, Jessica Y; Rothmann, Sabine; Schröder, Frank; Langen, Jennifer; Lücke, Thomas; Mariotti, François; Huneau, Jean François; Frölich, Jürgen C; Tsikas, Dimitrios

    2015-09-01

    Despite saturation of nitric oxide (NO) synthase (NOS) by its substrate L-arginine (Arg), oral and intravenous supplementation of Arg may enhance NO synthesis, a phenomenon known as "The L-arginine paradox". Yet, Arg is not only a source of NO, but is also a source for guanidine-methylated (N (G)) arginine derivatives which are all inhibitors of NOS activity. Therefore, Arg supplementation may not always result in enhanced NO synthesis. Concomitant synthesis of N (G)-monomethyl arginine (MMA), N (G),N (G)-dimethylarginine (asymmetric dimethylarginine, ADMA) and N (G),N (G´)-dimethylarginine (symmetric dimethylarginine, SDMA) from supplemented Arg may outweigh and even outbalance the positive effects of Arg on NO. Another possible, yet little investigated effect of Arg supplementation may be alteration of renal function, notably the influence on the excretion of nitrite in the urine. Nitrite is the autoxidation product of NO and the major reservoir of NO in the circulation. Nitrite and Arg are reabsorbed in the proximal tubule of the nephron and this reabsorption is coupled, at least in part, to the renal carbonic anhydrase (CA) activity. In the present placebo-controlled studies, we investigated the effect of chronic oral Arg supplementation of 10 g/day for 3 or 6 months in patients suffering from peripheral arterial occlusive disease (PAOD) or coronary artery disease (CAD) on the urinary excretion of nitrite relative to nitrate. We determined the urinary nitrate-to-nitrite molar ratio (UNOxR), which is a measure of nitrite-dependent renal CA activity before and after oral intake of Arg or placebo by the patients. The UNOxR was also determined in 6 children who underwent the Arg test, i.e., intravenous infusion of Arg (0.5 g Arg/kg bodyweight) for 30 min. Arg was well tolerated by the patients of the three studies. Oral Arg supplementation increased Arg (plasma and urine) and ADMA (urine) concentrations. No appreciable changes were seen in NO (in PAOD and CAD) and

  17. Apple Peel Supplemented Diet Reduces Parameters of Metabolic Syndrome and Atherogenic Progression in ApoE−/− Mice

    Science.gov (United States)

    Gonzalez, Jaime; Donoso, Wendy; Sandoval, Nathalie; Reyes, María; Gonzalez, Priscila; Gajardo, Monica; Morales, Erik; Neira, Amalia; Razmilic, Iván; Yuri, José A.

    2015-01-01

    Cardiovascular Diseases (CVD) represent about 30% of all causes of death worldwide. The development of CVD is related in many cases with the previous existence of metabolic syndrome (MS). It is known that apple consumption has a cardiovascular protecting effect, containing phenolic compounds with antioxidant effect, which are concentrated in the fruit peel. The objective of this study was to test the effect of apple peel consumption in a murine model of MS and apoE−/− mice. Apple supplemented diets reduced the biochemical parameters (glycaemia, total cholesterol, HDL-cholesterol, LDL-cholesterol, ureic nitrogen, triglycerides, insulin, and asymmetric dimethylarginine (ADMA)) of MS model in CF1 mice significantly. The model apoE−/− mouse was used to evaluate the capacity of the apple peel to revert the progression of the atherogenesis. FD with HAP reverts cholesterol significantly and slows down the progression of the plate diminishing the cholesterol accumulation area. With these results, it can be concluded that the consumption of apple peel reduces several MS parameters and the atherogenic progression in mice. PMID:26075004

  18. Resveratrol and Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Dominique Bonnefont-Rousselot

    2016-05-01

    Full Text Available The increased incidence of cardiovascular diseases (CVDs has stimulated research for substances that could improve cardiovascular health. Among them, resveratrol (RES, a polyphenolic compound notably present in grapes and red wine, has been involved in the “French paradox”. RES is known for its antioxidant and anti-inflammatory properties and for its ability to upregulate endothelial NO synthase (eNOS. RES was able to scavenge •OH/O2•− and peroxyl radicals, which can limit the lipid peroxidation processes. Moreover, in bovine aortic endothelial cells (BAEC under glucose-induced oxidative stress, RES restored the activity of dimethylargininedimethylaminohydrolase (DDAH, an enzyme that degrades an endogenous inhibitor of eNOS named asymmetric dimethylarginine (ADMA. Thus, RES could improve •NO availability and decrease the endothelial dysfunction observed in diabetes. Preclinical studies have made it possible to identify molecular targets (SIRT-1, AMPK, Nrf2, NFκB…; however, there are limited human clinical trials, and difficulties in the interpretation of results arise from the use of high-dose RES supplements in research studies, whereas low RES concentrations are present in red wine. The discussions on potential beneficial effects of RES in CVDs (atherosclerosis, hypertension, stroke, myocardial infarction, heart failure should compare the results of preclinical studies with those of clinical trials.

  19. Accelerated fat cell aging links oxidative stress and insulin resistance in adipocytes

    Indian Academy of Sciences (India)

    Finny Monickaraj; Sankaramoorthy Aravind; Pichamoorthy Nandhini; Paramasivam Prabu; Chandrakumar Sathishkumar; Viswanathan Mohan; Muthuswamy Balasubramanyam

    2013-03-01

    Telomere shortening is emerging as a biological indicator of accelerated aging and aging-related diseases including type 2 diabetes. While telomere length measurements were largely done in white blood cells, there is lack of studies on telomere length in relation to oxidative stress in target tissues affected in diabetes. Therefore, the aim of this study is to induct oxidative stress in adipocytes and to test whether these adipocytes exhibit shortened telomeres, senescence and functional impairment. 3T3-L1 adipocytes were subjected to oxidative stress and senescence induction by a variety of means for 2 weeks (exogenous application of H2O2, glucose oxidase, asymmetric dimethylarginine (ADMA) and glucose oscillations). Cells were probed for reactive oxygen species generation (ROS), DNA damage, mRNA and protein expression of senescent and pro-inflammatory markers, telomere length and glucose uptake. Compared to untreated cells, both ROS generation and DNA damage were significantly higher in cells subjected to oxidative stress and senescence. Adipocytes subjected to oxidative stress also showed shortened telomeres and increased mRNA and protein expression of p53, p21, TNF and IL-6. Senescent cells were also characterized by decreased levels of adiponectin and impaired glucose uptake. Briefly, adipocytes under oxidative stress exhibited increased ROS generation, DNA damage, shortened telomeres and switched to senescent/pro-inflammatory phenotype with impaired glucose uptake.

  20. Apple Peel Supplemented Diet Reduces Parameters of Metabolic Syndrome and Atherogenic Progression in ApoE−/− Mice

    Directory of Open Access Journals (Sweden)

    Jaime Gonzalez

    2015-01-01

    Full Text Available Cardiovascular Diseases (CVD represent about 30% of all causes of death worldwide. The development of CVD is related in many cases with the previous existence of metabolic syndrome (MS. It is known that apple consumption has a cardiovascular protecting effect, containing phenolic compounds with antioxidant effect, which are concentrated in the fruit peel. The objective of this study was to test the effect of apple peel consumption in a murine model of MS and apoE−/− mice. Apple supplemented diets reduced the biochemical parameters (glycaemia, total cholesterol, HDL-cholesterol, LDL-cholesterol, ureic nitrogen, triglycerides, insulin, and asymmetric dimethylarginine (ADMA of MS model in CF1 mice significantly. The model apoE−/− mouse was used to evaluate the capacity of the apple peel to revert the progression of the atherogenesis. FD with HAP reverts cholesterol significantly and slows down the progression of the plate diminishing the cholesterol accumulation area. With these results, it can be concluded that the consumption of apple peel reduces several MS parameters and the atherogenic progression in mice.

  1. 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.

  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. 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.

  4. 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.

  5. 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.

  6. Alanine-glyoxylate aminotransferase 2 (AGXT2) polymorphisms have considerable impact on methylarginine and β-aminoisobutyrate metabolism in healthy volunteers.

    Science.gov (United States)

    Kittel, Anja; Müller, Fabian; König, Jörg; Mieth, Maren; Sticht, Heinrich; Zolk, Oliver; Kralj, Ana; Heinrich, Markus R; Fromm, Martin F; Maas, Renke

    2014-01-01

    Elevated plasma concentrations of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine have repeatedly been linked to adverse clinical outcomes. Both methylarginines are substrates of alanine-glyoxylate aminotransferase 2 (AGXT2). It was the aim of the present study to simultaneously investigate the functional relevance and relative contributions of common AGXT2 single nucleotide polymorphisms (SNPs) to plasma and urinary concentrations of methylarginines as well as β-aminoisobutyrate (BAIB), a prototypic substrate of AGXT2. In a cohort of 400 healthy volunteers ADMA, SDMA and BAIB concentrations were determined in plasma and urine using HPLC-MS/MS and were related to the coding AGXT2 SNPs rs37369 (p.Val140Ile) and rs16899974 (p.Val498Leu). Volunteers heterozygous or homozygous for the AGXT2 SNP rs37369 had higher SDMA plasma concentrations by 5% and 20% (p = 0.002) as well as higher BAIB concentrations by 54% and 146%, respectively, in plasma and 237% and 1661%, respectively, in urine (both p<0.001). ADMA concentrations were not affected by both SNPs. A haplotype analysis revealed that the second investigated AGXT2 SNP rs16899974, which was not significantly linked to the other AGXT2 SNP, further aggravates the effect of rs37369 with respect to BAIB concentrations in plasma and urine. To investigate the impact of the amino acid exchange p.Val140Ile, we established human embryonic kidney cell lines stably overexpressing wild-type or mutant (p.Val140Ile) AGXT2 protein and assessed enzyme activity using BAIB and stable-isotope labeled [²H₆]-SDMA as substrate. In vitro, the amino acid exchange of the mutant protein resulted in a significantly lower enzyme activity compared to wild-type AGXT2 (p<0.05). In silico modeling of the SNPs indicated reduced enzyme stability and substrate binding. In conclusion, SNPs of AGXT2 affect plasma as well as urinary BAIB and SDMA concentrations linking methylarginine metabolism to the common genetic trait of hyper

  7. Alanine-glyoxylate aminotransferase 2 (AGXT2 polymorphisms have considerable impact on methylarginine and β-aminoisobutyrate metabolism in healthy volunteers.

    Directory of Open Access Journals (Sweden)

    Anja Kittel

    Full Text Available Elevated plasma concentrations of asymmetric (ADMA and symmetric (SDMA dimethylarginine have repeatedly been linked to adverse clinical outcomes. Both methylarginines are substrates of alanine-glyoxylate aminotransferase 2 (AGXT2. It was the aim of the present study to simultaneously investigate the functional relevance and relative contributions of common AGXT2 single nucleotide polymorphisms (SNPs to plasma and urinary concentrations of methylarginines as well as β-aminoisobutyrate (BAIB, a prototypic substrate of AGXT2. In a cohort of 400 healthy volunteers ADMA, SDMA and BAIB concentrations were determined in plasma and urine using HPLC-MS/MS and were related to the coding AGXT2 SNPs rs37369 (p.Val140Ile and rs16899974 (p.Val498Leu. Volunteers heterozygous or homozygous for the AGXT2 SNP rs37369 had higher SDMA plasma concentrations by 5% and 20% (p = 0.002 as well as higher BAIB concentrations by 54% and 146%, respectively, in plasma and 237% and 1661%, respectively, in urine (both p<0.001. ADMA concentrations were not affected by both SNPs. A haplotype analysis revealed that the second investigated AGXT2 SNP rs16899974, which was not significantly linked to the other AGXT2 SNP, further aggravates the effect of rs37369 with respect to BAIB concentrations in plasma and urine. To investigate the impact of the amino acid exchange p.Val140Ile, we established human embryonic kidney cell lines stably overexpressing wild-type or mutant (p.Val140Ile AGXT2 protein and assessed enzyme activity using BAIB and stable-isotope labeled [²H₆]-SDMA as substrate. In vitro, the amino acid exchange of the mutant protein resulted in a significantly lower enzyme activity compared to wild-type AGXT2 (p<0.05. In silico modeling of the SNPs indicated reduced enzyme stability and substrate binding. In conclusion, SNPs of AGXT2 affect plasma as well as urinary BAIB and SDMA concentrations linking methylarginine metabolism to the common genetic trait of hyper

  8. 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.

  9. Thermal transport across symmetric and asymmetric solid-solid interfaces

    Science.gov (United States)

    Bi, Kedong; Liu, Yadong; Zhang, Chunwei; Li, Jiapeng; Chen, Minhua; Chen, Yunfei

    2016-10-01

    Thermal transport across symmetric and asymmetric solid-solid interfaces is investigated by non-equilibrium molecular dynamics simulations. For symmetric interfaces, simulation results demonstrate that the thermal interface resistance is reduced greatly with the temperature increasing from 20 to 70 K. Besides, the introduction of an interlayer in the region of a highly mismatched interface is predicted to effectively decrease the thermal interface resistance due to the vibrational bridge role of the interlayer in connecting two vibrationally mismatched materials. As for the case of asymmetric interfaces, it is found that the capacity of thermal transport across an asymmetric interface is related to the effective interfacial area, namely the smaller cross-section area of component materials. In addition, effects of the transition angle at asymmetric interfaces on the thermal interface resistance are further studied when heat flows through interfaces from the side with larger cross-section area to the other. It is shown that a smoother transition is preferred for thermal transport through an asymmetric interface.

  10. Performance of JPEG Image Transmission Using Proposed Asymmetric Turbo Code

    Directory of Open Access Journals (Sweden)

    Siddiqi Mohammad Umar

    2007-01-01

    Full Text Available This paper gives the results of a simulation study on the performance of JPEG image transmission over AWGN and Rayleigh fading channels using typical and proposed asymmetric turbo codes for error control coding. The baseline JPEG algorithm is used to compress a QCIF ( "Suzie" image. The recursive systematic convolutional (RSC encoder with generator polynomials , that is, (13/11 in decimal, and 3G interleaver are used for the typical WCDMA and CDMA2000 turbo codes. The proposed asymmetric turbo code uses generator polynomials , that is, (13/11; 13/9 in decimal, and a code-matched interleaver. The effect of interleaver in the proposed asymmetric turbo code is studied using weight distribution and simulation. The simulation results and performance bound for proposed asymmetric turbo code for the frame length , code rate with Log-MAP decoder over AWGN channel are compared with the typical system. From the simulation results, it is observed that the image transmission using proposed asymmetric turbo code performs better than that with the typical system.

  11. 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.

  12. 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.

  13. Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter

    CERN Document Server

    Bishara, Fady

    2014-01-01

    Generically, the asymmetric interactions in asymmetric dark matter (ADM) models lead to decaying DM. We show that, for ADM that carries nonzero baryon number, the continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. The mediators for $B=2$ ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavor breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.

  14. Experimental Quantification of Asymmetric Einstein-Podolsky-Rosen Steering.

    Science.gov (United States)

    Sun, Kai; Ye, Xiang-Jun; Xu, Jin-Shi; Xu, Xiao-Ye; Tang, Jian-Shun; Wu, Yu-Chun; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2016-04-22

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one observer to nonlocally "steer" the other observer's state through local measurements. EPR steering exhibits a unique asymmetric property; i.e., the steerability can differ between observers, which can lead to one-way EPR steering in which only one observer obtains steerability in the steering process. This property is inherently different from the symmetric concepts of entanglement and Bell nonlocality, and it has attracted increasing interest. Here, we experimentally demonstrate asymmetric EPR steering for a class of two-qubit states in the case of two measurement settings. We propose a practical method to quantify the steerability. We then provide a necessary and sufficient condition for EPR steering and clearly demonstrate one-way EPR steering. Our work provides new insight into the fundamental asymmetry of quantum nonlocality and has potential applications in asymmetric quantum information processing. PMID:27152778

  15. Ballistic thermal rectification in asymmetric three-terminal graphene nanojunctions

    Science.gov (United States)

    Ouyang, Tao; Chen, Yuanping; Xie, Yuee; Wei, X. L.; Yang, Kaike; Yang, Ping; Zhong, Jianxin

    2010-12-01

    Graphene nanojunctions (GNJs) are important components of future nanodevices and nanocircuits. Using the nonequilibrium Green’s function method, we investigate the phononic properties of three-terminal GNJs (TGNJs). The results show that the heat flux runs preferentially along the direction from narrow to wide terminals, presenting an evident ballistic thermal rectification effect in the asymmetric TGNJs. The rectification efficiency is strongly dependent on the asymmetry of the nanojunctions, which increases rapidly with the width discrepancy between the left and right terminals. Meanwhile, the corner form of the TGNJs also plays an important role in the rectification effect. The mechanism of this thermal rectification is explained by a qualitative analysis. Compared to previous thermal rectifiers based on other materials, the asymmetric nanojunctions based on graphene possess much high rectification ratio which can approach about 200%. These indicate that asymmetric TGNJs might be a promising candidate for excellent ballistic thermal (phononic) devices.

  16. New Asymmetric Fuzzy PID Control for Pneumatic Position Control System

    Institute of Scientific and Technical Information of China (English)

    薛阳; 彭光正; 范萌; 伍清河

    2004-01-01

    A fuzzy control algorithm of asymmetric fuzzy strategy is introduced for a servo-pneumatic position system. It can effectively solve the difficult problems of single rod low friction cylinders, which are mainly caused by asymmetric structures and different friction characteristics in two directions. On the basis of this algorithm, a traditional PID control is used to improve dynamic performance. Furthermore, a new asymmetric fuzzy PID control with α factor is advanced to improve the self-adaptability and robustness of the system. Both the theoretical analyses and experimental results prove that, with this control strategy, the dynamic performance of the system can be greatly improved. The system using this control algorithm has strong robustness and it obtains desired overshoot and repeatability in both transient and steady-state responses.

  17. Equation of state and phase transitions in asymmetric nuclear matter

    CERN Document Server

    Kolomietz, V M; 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 calculations of the caloric curves in the case of isobaric heating. We have shown the presence of the plateau region in caloric curves at the isobaric heating of the asymmetric nuclear matter. The shape of the caloric curve depends on the pressure and is sensitive to the value of the asymmetry parameter. We point out that the experimental value of the plateau temperature T \\approx 7 MeV corresponds to the pressure P = 0.01 MeV/fm^3 at the isobaric boiling.

  18. Role of Asymmetric Clusters in Desynchronization of Coherent Motion

    DEFF Research Database (Denmark)

    Popovych, O.; Maistrenko, Y.; Mosekilde, Erik

    2002-01-01

    The transition from full synchronization (coherent motion) to two-cluster dynamics is studied for a system of N globally coupled logistic maps. When increasing the nonlinearity parameter of the individual map, new periodic and strongly asymmetric two-cluster states are found to emerge in the same...... order as the periodic windows arise in the logistic map. These strongly asymmetric two-cluster states are generally first to stabilize when reducing the coupling strength. Similar phenomena are also observed for a system of globally coupled Henon maps.......The transition from full synchronization (coherent motion) to two-cluster dynamics is studied for a system of N globally coupled logistic maps. When increasing the nonlinearity parameter of the individual map, new periodic and strongly asymmetric two-cluster states are found to emerge in the same...

  19. Asymmetric spindle pole formation in CPAP-depleted mitotic cells.

    Science.gov (United States)

    Lee, Miseon; Chang, Jaerak; Chang, Sunghoe; Lee, Kyung S; Rhee, Kunsoo

    2014-02-21

    CPAP is an essential component for centriole formation. Here, we report that CPAP is also critical for symmetric spindle pole formation during mitosis. We observed that pericentriolar material between the mitotic spindle poles were asymmetrically distributed in CPAP-depleted cells even with intact numbers of centrioles. The length of procentrioles was slightly reduced by CPAP depletion, but the length of mother centrioles was not affected. Surprisingly, the young mother centrioles of the CPAP-depleted cells are not fully matured, as evidenced by the absence of distal and subdistal appendage proteins. We propose that the selective absence of centriolar appendages at the young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells. Our results suggest that the neural stem cells with CPAP mutations might form asymmetric spindle poles, which results in premature initiation of differentiation.

  20. Phase-transfer-catalysed asymmetric synthesis of tetrasubstituted allenes

    Science.gov (United States)

    Hashimoto, Takuya; Sakata, Kazuki; Tamakuni, Fumiko; Dutton, Mark J.; Maruoka, Keiji

    2013-03-01

    Allenes are molecules based on three carbons connected by two cumulated carbon-carbon double bonds. Given their axially chiral nature and unique reactivity, substituted allenes have a variety of applications in organic chemistry as key synthetic intermediates and directly as part of biologically active compounds. Although the demands for these motivated many endeavours to make axially chiral, substituted allenes by exercising asymmetric catalysis, the catalytic asymmetric synthesis of fully substituted ones (tetrasubstituted allenes) remained largely an unsolved issue. The fundamental obstacle to solving this conundrum is the lack of a simple synthetic transformation that provides tetrasubstituted allenes in the action of catalysis. We report herein a strategy to overcome this issue by the use of a phase-transfer-catalysed asymmetric functionalization of 1-alkylallene-1,3-dicarboxylates with N-arylsulfonyl imines and benzylic and allylic bromides.

  1. 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.

  2. Experimental Quantification of Asymmetric Einstein-Podolsky-Rosen Steering.

    Science.gov (United States)

    Sun, Kai; Ye, Xiang-Jun; Xu, Jin-Shi; Xu, Xiao-Ye; Tang, Jian-Shun; Wu, Yu-Chun; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2016-04-22

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one observer to nonlocally "steer" the other observer's state through local measurements. EPR steering exhibits a unique asymmetric property; i.e., the steerability can differ between observers, which can lead to one-way EPR steering in which only one observer obtains steerability in the steering process. This property is inherently different from the symmetric concepts of entanglement and Bell nonlocality, and it has attracted increasing interest. Here, we experimentally demonstrate asymmetric EPR steering for a class of two-qubit states in the case of two measurement settings. We propose a practical method to quantify the steerability. We then provide a necessary and sufficient condition for EPR steering and clearly demonstrate one-way EPR steering. Our work provides new insight into the fundamental asymmetry of quantum nonlocality and has potential applications in asymmetric quantum information processing.

  3. Solitary waves in asymmetric electron-positron-ion plasmas

    Science.gov (United States)

    Lu, Ding; Li, Zi-Liang; Xie, Bai-Song

    2015-10-01

    > By solving the coupled equations of the electromagnetic field and electrostatic potential, we investigate solitary waves in an asymmetric electron-positron plasma and/or electron-positron-ion plasmas with delicate features. It is found that the solutions of the coupled equations can capture multipeak structures of solitary waves in the case of cold plasma, which are left out by using the long-wavelength approximation. By considering the effect of ion motion with respect to non-relativistic and ultra-relativistic temperature plasmas, we find that the ions' mobility can lead to larger-amplitude solitary waves; especially, this becomes more obvious for a high-temperature plasma. The effects of asymmetric temperature between electrons and positrons and the ion fraction on the solitary waves are also studied and presented. It is shown that the amplitudes of solitary waves decrease with positron temperature in asymmetric temperature electron-positron plasmas and decrease also with ion concentration.

  4. Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin.

    Science.gov (United States)

    Ogrodnik, Mikołaj; Salmonowicz, Hanna; Brown, Rachel; Turkowska, Joanna; Średniawa, Władysław; Pattabiraman, Sundararaghavan; Amen, Triana; Abraham, Ayelet-chen; Eichler, Noam; Lyakhovetsky, Roman; Kaganovich, Daniel

    2014-06-01

    Aging is associated with the accumulation of several types of damage: in particular, damage to the proteome. Recent work points to a conserved replicative rejuvenation mechanism that works by preventing the inheritance of damaged and misfolded proteins by specific cells during division. Asymmetric inheritance of misfolded and aggregated proteins has been shown in bacteria and yeast, but relatively little evidence exists for a similar mechanism in mammalian cells. Here, we demonstrate, using long-term 4D imaging, that the vimentin intermediate filament establishes mitotic polarity in mammalian cell lines and mediates the asymmetric partitioning of damaged proteins. We show that mammalian JUNQ inclusion bodies containing soluble misfolded proteins are inherited asymmetrically, similarly to JUNQ quality-control inclusions observed in yeast. Mammalian IPOD-like inclusion bodies, meanwhile, are not always inherited by the same cell as the JUNQ. Our study suggests that the mammalian cytoskeleton and intermediate filaments provide the physical scaffold for asymmetric inheritance of dynamic quality-control JUNQ inclusions. Mammalian IPOD inclusions containing amyloidogenic proteins are not partitioned as effectively during mitosis as their counterparts in yeast. These findings provide a valuable mechanistic basis for studying the process of asymmetric inheritance in mammalian cells, including cells potentially undergoing polar divisions, such as differentiating stem cells and cancer cells.

  5. Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill%Control Strategies of Asymmetric Strip Shape in Six-High Cold Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun; YANG Quan; WANG Xiao-chen

    2011-01-01

    It is a complicated problem for cold-rolled strip to improve asymmetric strip shape in strip production. A roll system and strip coupled model of six-high cold rolling mill was established with finite element method to estimate the effect of intermediate roll shifting, tilting, symmetric and asymmetric bending technologies on strip profile. To reduce asymmetric defects of strip shape as much as possible, some control strategies were proposed, including tilting and asymmetric bending of intermediate roll and work roll. The combinations of these three control strategies can effectively eliminate asymmetric strip shape defects. Finally, the closed-loop control model of asymmetric flat- ness at the last stand was given, and the flatness control system with the function of asymmetric strip shape control was also designed for cold tandem mill.

  6. Possible origin of transition from symmetric to asymmetric fission

    Science.gov (United States)

    Paşca, H.; Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.

    2016-09-01

    The charged distributions of fragments produced in the electromagnetic-induced fission of the even-even isotopes of Rn, Ra, Th, and U are described within an improved scission-point model and compared with the available experimental data. The three-equal-peaked charge distributions are predicted for several fissioning nuclei with neutron number N = 136. The possible explanation of the transition from a symmetric fission mode to an asymmetric one around N ∼ 136 is presented. The excitation energy dependencies of the asymmetric and symmetric fission modes are anticipated.

  7. Recent advances in copper-catalyzed asymmetric coupling reactions

    Directory of Open Access Journals (Sweden)

    Fengtao Zhou

    2015-12-01

    Full Text Available Copper-catalyzed (or -mediated asymmetric coupling reactions have received significant attention over the past few years. Especially the coupling reactions of aryl or alkyl halides with nucleophiles became a very powerful tool for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds as well as for the construction of heteroatom-containing ring systems. This review summarizes the recent progress in copper-catalyzed asymmetric coupling reactions for the formation of C–C and carbon–heteroatom bonds.

  8. THE PROBLEM OF AN EXTERNAL CIRCULAR CRACK UNDER ASYMMETRIC LOADINGS

    Institute of Scientific and Technical Information of China (English)

    王银邦

    2001-01-01

    Using the boundary integral equation method, the problem of an external circular crack in a three-dimensional infinite elastic body under asymmetric loadings is investigated. The two- dimensional singular boundary integral equations of the problem were reduced to a system of Abel integral equations by means of Fourier series and hypergeometric functions. The exact solutions of stress intensity factors are obtained for the problem of an external circular crack under asymmetric loadings, which are even more universal than the results obtained by the use of Hankel transform method. The results demonstrate that the boundary integral equation method has great potential as a new analytic method.

  9. Imperfect pitchfork bifurcation in asymmetric two-compartment granular gas

    Institute of Scientific and Technical Information of China (English)

    Zhang Yin; Li Yin-Chang; Liu Rui; Cui Fei-Fei; Pierre Evesque; Hou Mei-Ying

    2013-01-01

    The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup.Unlike the random clustering in either compartment in the case of symmetric configuration when lowering the shaking strength to below a critical value,the directed clustering is observed,which corresponds to an imperfect pitchfork bifurcation.Numerical solutions of the flux equation using a modified simple flux function show qualitative agreements with the experimental results.The potential application of this asymmetric structure is discussed.

  10. DYNAMICS OF THE ZONAL ASYMMETRIC STRUCTURE OF ARCTIC OSCILLATION

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-hong; YU Wei-dong; LUO Ti-qian

    2004-01-01

    The Arctic Oscillation(AO),though basically is a zonal symmetric phenomenon,also shows zonal asymmetric variation.The dynamics of this zonal variation is considered here from the point of view of the planetary propagation on the earth sphere.Based on the linear barotropic vorticity equation,the planetary wave ray path is calculated in the winter January.It shows that NAO(North Atlantic Oscillation),AO and North Pacific could be linked through the planetary wave propagation,which acts as the atmospheric bridge.The zonal symmetric and asymmetric structures both have association with these Rossby wave activities.

  11. 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.

  12. Generation of isolated asymmetric umbilics in light's polarization

    CERN Document Server

    Galvez, Enrique J; Kumar, Vijay; Viswanathan, Nirmal K

    2014-01-01

    Polarization-singularity C-points, a form of line singularities, are the vectorial counterparts of the optical vortices of spatial modes and fundamental optical features of polarization-spatial modes. Their generation in tailored beams has been limited to lemon and star C-points that contain symmetric dislocations in state-of-polarization patterns. In this article we present the theory and laboratory measurements of two complementary methods to generate isolated asymmetric C-points in tailored beams, of which symmetric lemons and stars are limiting cases; and we report on the generation of monstars, an asymmetric C-point with characteristics of both lemons and stars.

  13. An optical tweezer in asymmetrical vortex Bessel-Gaussian beams

    Science.gov (United States)

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

    2016-07-01

    We study an optical micromanipulation that comprises trapping, rotating, and transporting 5-μm polystyrene microbeads in asymmetric Bessel-Gaussian (BG) laser beams. The beams that carry orbital angular momentum are generated by means of a liquid crystal microdisplay and focused by a microobjective with a numerical aperture of NA = 0.85. We experimentally show that given a constant topological charge, the rate of microparticle motion increases near linearly with increasing asymmetry of the BG beam. Asymmetric BG beams can be used instead of conventional Gaussian beam for trapping and transferring live cells without thermal damage.

  14. Spectroscopic calculation of asymmetric top free radicals: method and program

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper sketches out the effective Hamiltonian and basis set adopted in the spectroscopic calcula tion of asymmetric top free radicals, and details the machine implementation of the spectral analysis of asymmetric top free radicals, the design and usage of the program package. To demonstrate the application of this program, analyses have been performed on the far infrared laser magnetic resonance spectrum of 14N16O2( I = 1) and the infrared diode laser spectrum of the v3 band of PO2( I = 1/2) using the program.

  15. 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...

  16. 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  ……

  17. Catalytic Asymmetric Total Synthesis of Hedyosumins A, B, and C.

    Science.gov (United States)

    Sun, Wang-Bin; Wang, Xuan; Sun, Bing-Feng; Zou, Jian-Ping; Lin, Guo-Qiang

    2016-03-18

    The first and asymmetric total synthesis of hedyosumins A, B, and C was accomplished in 13-14 steps from simple starting materials. The essential tools that allow us to access the tetracyclic skeleton include an organocatalytic [4 + 3] cycloaddition reaction, an intramolecular aldol condensation, and an intramolecular carboxymercuration/demercuration enabled lactonization. A CBS-catalyzed asymmetric reduction was employed to boost the ee of the synthetic natural products to an excellent level. This synthesis established the absolute configurations of hedyosumins A, B, and C. PMID:26925758

  18. Price Asymmetric Relationships in Commodity and Energy Markets

    OpenAIRE

    Wixson, Sarah E.; Katchova, Ani L.

    2012-01-01

    Recent increases in the price of crude oil have led to a rise in the prominence of corn-based ethanol as an alternative source of energy. As a result linkages have been established between commodity and energy prices. The aim of this study is to determine if soybeans, corn, wheat, oil, and ethanol adjust their prices asymmetrically depending on whether their actual price is over or under-predicted with respect to one another. This study’s goal of determining if asymmetric price relationships ...

  19. 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

  20. Rectification of motion in nonlinear media with asymmetric random drive

    International Nuclear Information System (INIS)

    We consider moving particles in media with nonlinear friction and drive them by an asymmetric dichotomic Markov process. Due to different energy dissipations, during the forward and backward stroke, we obtain a mean non-vanishing directed flow of the particles. Starting with the stationary velocity distribution, we calculate the stationary current of particles, the variance and the relative variance in dependence on the degree of nonlinearity of the friction, on the asymmetry and for different strengths of friction. In two dimensions the particle performs diffusional motion, if in addition the direction of the asymmetric drive changes stochastically.

  1. Tunable Dirac points and perfect transmission in asymmetric graphene superlattices

    Science.gov (United States)

    Zhang, Rui-Li; Li, Jin-Jing; Zhou, Yu; Peng, Ru-Wen; Huang, Run-Sheng; Wang, Mu

    2015-08-01

    We investigated the electronic band structures and transport properties in asymmetric graphene superlattices (AGSLs). Their asymmetric distribution of potentials can induce extra Dirac points (DPs) that are absent in periodic and symmetric graphene superlattices. The emergence and location of the DPs in the k space can be manipulated by selecting the special structure of the AGSL. As a result, tunable perfect transmissions are obtained in the system. Moreover, the conductance and Fano factor present interesting oscillatory behaviors. These findings may be used for the design of graphene-based electronic devices.

  2. Careful numerical study of flowfields about asymmetric external conical corners

    Science.gov (United States)

    Salas, M. D.

    1980-01-01

    A numerical study of the flowfield about asymmetrical external axial corners formed by the juncture of swept compressive wedges is presented. The geometrical configuration allows a unified treatment of external corners typical of delta wings and rectangular inlets. The study investigates how the flow transitions from a symmetrical flowfield with a cross-flow stagnation point at the corner to an asymmetrical flowfield for which the flow spills over the corner. The effects of leading-edge sweep, wedge compression, and corner radius are investigated.

  3. Asymmetric Mutualism in Two- and Three-Dimensional Range Expansions

    Science.gov (United States)

    Lavrentovich, Maxim O.; Nelson, David R.

    2014-04-01

    Genetic drift at the frontiers of two-dimensional range expansions of microorganisms can frustrate local cooperation between different genetic variants, demixing the population into distinct sectors. In a biological context, mutualistic or antagonistic interactions will typically be asymmetric between variants. By taking into account both the asymmetry and the interaction strength, we show that the much weaker demixing in three dimensions allows for a mutualistic phase over a much wider range of asymmetric cooperative benefits, with mutualism prevailing for any positive, symmetric benefit. We also demonstrate that expansions with undulating fronts roughen dramatically at the boundaries of the mutualistic phase, with severe consequences for the population genetics along the transition lines.

  4. Smurfs have "fused" into the asymmetric division of stem cells

    Institute of Scientific and Technical Information of China (English)

    Steven Y. Cheng; Ying E. Zhang

    2011-01-01

    @@ The asymmetric cell division is the way in which a stem cell divides into one daughter stem cell and one differentiated daughter cell.This process is one of the key principles of developmental biology that ensures the perpetual supply of stem cells while allowing a particular cell lineage to be populated.During Drosophila oogenesis, the fate of the daughter stem cell produced from the asymmetric division of germline stem cells (GSCs) is specified by Decapentaplegic (Dpp), but the other daughter cell has almost equal access to the Dpp signal.

  5. Asymmetric Domain Walls of Small Angle in Soft Ferromagnetic Films

    Science.gov (United States)

    Döring, Lukas; Ignat, Radu

    2016-05-01

    We focus on a special type of domain wall appearing in the Landau-Lifshitz theory for soft ferromagnetic films. These domain walls are divergence-free S^2-valued transition layers that connect two directions {m_θ^± in S^2} (differing by an angle {2θ}) and minimize the Dirichlet energy. Our main result is the rigorous derivation of the asymptotic structure and energy of such "asymmetric" domain walls in the limit {θ downarrow 0}. As an application, we deduce that a supercritical bifurcation causes the transition from symmetric to asymmetric walls in the full micromagnetic model.

  6. Salt supply to and significance of asymmetric salt diapirs

    DEFF Research Database (Denmark)

    Koyi, H.; Burliga, S.; Chemia, Zurab

    2012-01-01

    Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...

  7. Asymmetric transportation induced by thermal noise at the nanoscale

    Institute of Scientific and Technical Information of China (English)

    WAN RongZheng; HU Jun; FANG HaiPing

    2012-01-01

    Based on a simple model,we theoretically show that asymmetric transportation is possible in nanoscale systems experiencing thermal noise without the presence of external fluctuations.The key to this theoretical advance is that the correlation lengths of the thermal fluctuations become significantly long for nanoscale systems.This differs from macroscopic systems in which the thermal noises are usually treated as white noise.Our observation does not violate the second law of thermodynamics,since at the nanoscale,extra energy is required to keep the asymmetric structure against thermal fluctuations.

  8. Six transformer based asymmetrical embedded Z-source inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Poh Chiang, Loh; Chi, Jin;

    2013-01-01

    Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a ...... a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally....

  9. Chemoepitaxial guiding underlayers for density asymmetric and energetically asymmetric diblock copolymers

    Science.gov (United States)

    Nation, Benjamin D.; Ludovice, Peter J.; Henderson, Clifford L.

    2016-04-01

    Block copolymers, polymers composed of two or more homopolymers covalently bonded together, are currently being investigated as a method to extend optical lithography due to their ability to microphase separate on small size scales. In order to drive down the size that these BCPs phase separate, the BCPs with larger Flory-Huggin's χparameter needs to be found. Typically these BCPs are composed of more dissimilar homopolymers. However, changing these interactions also changes how BCPs interact with their guiding underlayers. In this paper, several block copolymers are simulated annealing on chemoepitaxial guiding underlayers using a coarse-grained molecular dynamics model in order to explore the effect that either energetic asymmetry or density asymmetry in the BCP have on the pattern registration. It is found that energetic asymmetry in BCPs causes one of the blocks to desire to skin, which shifts the composition of the background region that leads to well aligned vertical lamellae formation. It is hypothesized that moderate footing and undercutting at the underlayer or slight skinning at the free surface can increase the kinetics of defect annihilation by decreasing the distance that bridges must form. The density asymmetric BCPs simulated in this paper have different mechanical properties which lead to straighter sidewalls in the BCP film and potentially lead to better pattern registration. It is hypothesized that altering the compressibility of the blocks can alter equilibrium defectivity.

  10. On te generic stability of mixed strategies in asymmetric contests

    NARCIS (Netherlands)

    Bhaskar, V.

    1995-01-01

    Although a mixed strategy can never be evolutionarily stable in a truly asymmetric contest, examples show that mixed strategies can satisfy the weaker criterion on neutral stability. This paper shows that such examples are rare, and, generically, a mixed strategy is unstable. We apply the result to

  11. 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…

  12. Sensory feedback and coordinating asymmetrical landing in toads.

    Science.gov (United States)

    Cox, S M; Gillis, Gary B

    2016-06-01

    Coordinated landing requires anticipating the timing and magnitude of impact, which in turn requires sensory input. To better understand how cane toads, well known for coordinated landing, prioritize visual versus vestibular feedback during hopping, we recorded forelimb joint angle patterns and electromyographic data from five animals hopping under two conditions that were designed to force animals to land with one forelimb well before the other. In one condition, landing asymmetry was due to mid-air rolling, created by an unstable takeoff surface. In this condition, visual, vestibular and proprioceptive information could be used to predict asymmetric landing. In the other, animals took off normally, but landed asymmetrically because of a sloped landing surface. In this condition, sensory feedback provided conflicting information, and only visual feedback could appropriately predict the asymmetrical landing. During the roll treatment, when all sensory feedback could be used to predict an asymmetrical landing, pre-landing forelimb muscle activity and movement began earlier in the limb that landed first. However, no such asymmetries in forelimb preparation were apparent during hops onto sloped landings when only visual information could be used to predict landing asymmetry. These data suggest that toads prioritize vestibular or proprioceptive information over visual feedback to coordinate landing. PMID:27247440

  13. Three-party quantum teleportation with asymmetric states

    International Nuclear Information System (INIS)

    In this paper, we consider the three-party quantum teleportation using non-symmetric states. Considering all possible teleportation scenarios in the three-party quantum teleportation, we show that the asymmetric teleportation would carry more information than symmetrical ones. We also discuss the relation between teleportation protocols and quantum states classficition

  14. Asymmetric Monotone Comparative Statics for the Industry Compositions

    DEFF Research Database (Denmark)

    Laugesen, Anders Rosenstand

    Within a standard model of international trade with heterogeneous firms and two asymmetric countries, we derive sufficient conditions for monotone comparative statics (MCS) for the industry composition. This model outcome is defined as first-order stochastic dominance shifts in the equilibrium di...

  15. Synthesis of the 1,3-oxathiolanes using asymmetrically oxiranes

    Institute of Scientific and Technical Information of China (English)

    Faramarz Rostami-Charati; Zinatossadat Hossaini; Bita Mohtat; Mehdi Shahraki; Mohammad R. Hosseini-Tabatabaei

    2011-01-01

    An efficient synthesis of 1,3-oxathiolane-2-imin derivatives is described via one-pot reaction between arylisothiocyanats, asymmetrically substituted oxiranes and catalytic amount of methanol. The mild reaction conditions and high yields of the products exhibit the good synthetic advantage of this method.

  16. Phase diagram of highly asymmetric binary hardsphere mixtures

    NARCIS (Netherlands)

    Dijkstra, M.; van Roij, R.H.H.G.; Evans, R.

    1999-01-01

    We study the phase behavior and structure of highly asymmetric binary hard-sphere mixtures. By first integrating out the degrees of freedom of the small spheres in the partition function we derive a formal expression for the effective Hamiltonian of the large spheres. Then using an explicit pairwise

  17. Thermal rectification in three-dimensional asymmetric nanostructure.

    Science.gov (United States)

    Lee, Jonghoon; Varshney, Vikas; Roy, Ajit K; Ferguson, John B; Farmer, Barry L

    2012-07-11

    Previously, thermal rectification has been reported in several low-dimensional shape-asymmetric nanomaterials. In this Letter, we demonstrate that a three-dimensional crystalline material with an asymmetric shape also displays as strong thermal rectification as low-dimensional materials do. The observed rectification is attributed to the stronger temperature dependence of vibration density of states in the narrower region of the asymmetric material, resulting from the small number of atomic degrees of freedom directly interacting with the thermostat. We also demonstrate that the often reported "device shape asymmetry" is not a sufficient condition for thermal rectification. Specifically, the size asymmetry in boundary thermal contacts is equally important toward determining the magnitude of thermal rectification. When the boundary thermal contacts retain the same size asymmetry as the nanomaterial, the overall system displays notable thermal rectification, in accordance with existing literature. However, when the wider region of the asymmetric nanomaterial is partially thermostatted by a smaller sized contact, thermal rectification decreases dramatically and even changes direction.

  18. Market Efficiency and Price Formation When Dealers are Asymmetrically Informed

    NARCIS (Netherlands)

    Calcagno, R.; Lovo, S.M.

    2002-01-01

    We consider the effect of asymmetric information on the price formation process in a quote-driven market where one market maker receives a private signal on the security fundamental.A model is presented where market makers repeatedly compete in prices: at each stage a bid-ask auction occurs and the

  19. 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

  20. Sensory feedback and coordinating asymmetrical landing in toads.

    Science.gov (United States)

    Cox, S M; Gillis, Gary B

    2016-06-01

    Coordinated landing requires anticipating the timing and magnitude of impact, which in turn requires sensory input. To better understand how cane toads, well known for coordinated landing, prioritize visual versus vestibular feedback during hopping, we recorded forelimb joint angle patterns and electromyographic data from five animals hopping under two conditions that were designed to force animals to land with one forelimb well before the other. In one condition, landing asymmetry was due to mid-air rolling, created by an unstable takeoff surface. In this condition, visual, vestibular and proprioceptive information could be used to predict asymmetric landing. In the other, animals took off normally, but landed asymmetrically because of a sloped landing surface. In this condition, sensory feedback provided conflicting information, and only visual feedback could appropriately predict the asymmetrical landing. During the roll treatment, when all sensory feedback could be used to predict an asymmetrical landing, pre-landing forelimb muscle activity and movement began earlier in the limb that landed first. However, no such asymmetries in forelimb preparation were apparent during hops onto sloped landings when only visual information could be used to predict landing asymmetry. These data suggest that toads prioritize vestibular or proprioceptive information over visual feedback to coordinate landing.

  1. Purcell effect of asymmetric dipole source distributions in nanowire resonators

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Adam, Jost;

    of the asymmetric source distributions in proximity to the metal nanowire in two configurations: a metal cylinder truncated by the PEC plates and finite metal cylinder in free-space. In order to evaluate Purcell factor the mode eigenvalues are precalculated using Comsol Multiphysics radio frequency module. We...

  2. Purcell effect of asymmetric dipole source distributions in nanowire resonators

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Adam, Jost;

    2015-01-01

    of the asymmetric source distributions in proximity to the metal nanowire in two configurations: a metal cylinder truncated by the PEC plates and finite metal cylinder in free-space. In order to evaluate Purcell factor the mode eigenvalues are precalculated using Comsol Multiphysics radio frequency module. We...

  3. Asymmetric Prefrontal Cortex Functions Predict Asymmetries in Number Space

    Science.gov (United States)

    Bachmann, Valerie; Fischer, Martin H.; Landolt, Hans-Peter; Brugger, Peter

    2010-01-01

    Little is known about the neuropsychological factors that contribute to individual differences in the asymmetric orientation along the mental number line. The present study documents healthy subjects' preference for small numbers over large numbers in a random number generation task. This preference, referred to as "small-number bias" (SNB),…

  4. Self-organization of directed networks through asymmetric coupling

    International Nuclear Information System (INIS)

    In this Letter, self-organization of directed networks is surveyed. Inspired from the results in neural networks research, we propose an asymmetric coupling scheme with simple edge deleting rules. Results show that all-to-all networks can be organized into scale-free networks with feed-forward structures. Corresponding analysis is also given.

  5. A Novel Asymmetric ent-Kauranoid Dimer from Isodon enanderianus

    Institute of Scientific and Technical Information of China (English)

    NA,Zhi(纳智); LI,Sheng-Hong(黎胜红); XIANG,Wei(项伟); ZHAO,Ai-Hua(赵爱华); LI,Chao-Ming(李朝明); SUN,Han-Dong(孙汉董)

    2002-01-01

    Further investigation on the aerial parts of Isodon enanderianus afforded a novel asymmetric ent-kauranoid dimer, enanuderinaninJ (1). The structure of the dimer was elucidated by means of spectroscopic methods (including 2D NMR techniques ). Enanderinanin J was a dimer of xerophilusin A and probably formed by [ 4 + 2] cycloaddition.

  6. A Nove Asymmetric ent—Kauranoid Dimer from Isodon enanderianus

    Institute of Scientific and Technical Information of China (English)

    纳智; 黎胜红; 等

    2002-01-01

    Further investigation on the aerial parts of Isodon enanderianus afforded a novel asymmetric ent-kauranoid dimer,enanderi-nanin J(1).The structure of the dimer was elucidated by means of spectroscopic methods (including 2D NMR tecniques ),Enanderinanin J was a dimer of xerophilusin A and probably formed by [4+2] cycloaddition.

  7. Novel FinFET Device Using Asymmetric Doping

    DEFF Research Database (Denmark)

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional...

  8. 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

  9. Highly Birefringent Photonic Crystal Fibers BUsing Asymmetric Core Design

    Institute of Scientific and Technical Information of China (English)

    Zhao Chun-Liu; Lu Chao; Yan Min; Wang Xiaoyan; Lou Junjun; Li Qin; Zhou Xiaoqun; Cai Qing; P.R.Chaudhuri

    2003-01-01

    We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.

  10. The Analysis on Translation System Based on Asymmetric Cyclic Polling

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By the imbedded Markov chain theory and the probability generating function method, this paper discusses the queuing model of the switch node at the router and analyzes the derivative characters of first and second order of discrete asymmetric tri-queuing gate polling system. The average waiting time and the average queuing length are explicitly obtained and these results are verified by simulation.

  11. Asymmetric Modulation Gains in Network Coded Relay Networks

    DEFF Research Database (Denmark)

    Roetter, Daniel Enrique Lucani; Fitzek, Frank

    2015-01-01

    –to–end throughput by (i) using network coding to control the use of the relay in an effective manner, and (ii) leveraging asymmetric modulation to enable the source to efficiently allocate its resources. We provide mathematical analysis and a simple optimization mechanism. Numerical results for the case of fading...

  12. Quality Characteristics Distribution and Its Simulation Based on Asymmetric Tolerances

    Institute of Scientific and Technical Information of China (English)

    ZHU Wei; LI Yuan-sheng

    2003-01-01

    The application of normal distribution for quality characteristics has its limits on the condition that specification interval is asymmetric. In this paper, the compound normal distribution N(L,σ21,σ22) was proposed and simulated, the property of the parameters L、σ1 and σ2 was studied. The distribution was further applied toangle quality process control.

  13. 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.

  14. Accelerating foreign-key joins using asymmetric memory channels

    NARCIS (Netherlands)

    H. Pirk; S. Manegold; M. Kersten

    2011-01-01

    Indexed Foreign-Key Joins expose a very asymmetric access pattern: the Foreign-Key Index is sequentially scanned whilst the Primary-Key table is target of many quasi-random lookups which is the dominant cost factor. To reduce the costs of the random lookups the fact-table can be (re-) partitioned at

  15. Isoscalar dipole transition as a probe for asymmetric clustering

    Science.gov (United States)

    Chiba, Y.; Kimura, M.; Taniguchi, Y.

    2016-03-01

    Background: The sharp 1- resonances with enhanced isoscalar dipole transition strengths are observed in many light nuclei at relatively small excitation energies, but their nature has been unclear. Purpose: We show those resonances can be attributed to the cluster states with asymmetric configurations such as α +16O . We explain why asymmetric cluster states are strongly excited by the isoscalar dipole transition. We also provide a theoretical prediction of the isoscalar dipole transitions in 20Ne and 44Ti. Method: The transition matrix is analytically derived to clarify the excitation mechanism. The nuclear model calculations by Brink-Bloch wave function and antisymmetrized molecular dynamics are also performed to provide a theoretical prediction for 20Ne and 44Ti. Results: It is shown that the transition matrix is as large as the Weisskopf estimate even though the ground state is an ideal shell-model state. Furthermore, it is considerably amplified if the ground state has cluster correlation. The nuclear model calculations predict large transition matrix to the α +16O and α +40Ca cluster states comparable with or larger than the Weisskopf estimate. Conclusions: We conclude that the asymmetric cluster states are strongly excited by the isoscalar dipole transition. Combined with the isoscalar monopole transition that populates the 0+ cluster states, the isoscalar transitions are promising probes for asymmetric clusters.

  16. Highly Birefringent Photonic Crystal Fibers B Using Asymmetric Core Design

    Institute of Scientific and Technical Information of China (English)

    Zhao; Chun-Liu; Lu; Chao; Yan; Min; Wane; Xiaoyan; Lou; Junjun; Li; Qin; Zhou; Xiaoqun

    2003-01-01

    We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.

  17. Attempt to accelerate asymmetric species with unequal frequencies in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-07-09

    This report summarizes the beam studies on accelerating asymmetric beams with unequal frequencies, during the proton-Gold/Aluminum run in 2015. The experiment failed due to modulated beam-beam effects even though the beams were separated by at least 15 mm.

  18. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial

    Directory of Open Access Journals (Sweden)

    Igor Nefedov

    2015-05-01

    Full Text Available We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM, strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  19. Exact solution of lossy asymmetrical coupled dielectric slab waveguides

    OpenAIRE

    Young, P R; Collier, R J

    2001-01-01

    This paper gives an exact characteristic equation for asymmetrical coupled dielectric slab waveguides with losses in both the guiding and surrounding regions. For the lossless case the solution of a single transcendental equation is all that is required for the evaluation of the propagation constant.

  20. 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

  1. Asymmetric Threat Assessment Using Electro-Optical Image Systems

    NARCIS (Netherlands)

    Schwering, P.B.W.; Schutte, K.

    2010-01-01

    Asymmetric threat assessment from military platforms, including early detection and classification by electro-optical means, is a complicated matter. These threats can be for instance explosives-packed rubber boats, minecarrying swimmers and divers in a marine environment or terrorists, improvised e

  2. Asymmetric block copolymers confined in a thin film

    NARCIS (Netherlands)

    Huinink, HP; Brokken-Zijp, JCM; van Dijk, MA; Sevink, GJA

    2000-01-01

    We have used a dynamic density functional theory (DDFT) for polymeric systems, to simulate the formation of micro phases in a melt of an asymmetric block copolymer, A(n)B(m)(f(A) = 1/3), both in the bulk and in a thin film. In the DDFT model a polymer is represented as a chain of springs and beads.

  3. New approaches in asymmetric synthesis using γ-alkoxybutenolides

    NARCIS (Netherlands)

    Lange, Ben de; Jansen, Johan F.G.A.; Jong, Johannes C. de; Lubben, Marcel; Faber, Wijnand; Schudde, Ebe P.; Feringa, Bernard

    1992-01-01

    The synthesis of a new class of auxiliary based chiral synthons, γ-alkoxy-2(5H)-furanones, is described. The multifunctional compounds enter a variety of asymmetric transformations leading to acyclic- and cyclic-products with up to four new stereogenic centers in a single operation with stereoselect

  4. Unexpected phase behavior of an asymmetric diblock copolymer

    DEFF Research Database (Denmark)

    Papadakis, Christine Maria; Almdal, Kristoffer; Mortensen, Kell;

    1999-01-01

    We report on measurements of the transmitted depolarized light intensity and on small-angle neutron scattering (SANS) measurements on a compositionally asymmetric poly(ethylene propylene)-poly(dimethylsiloxane) diblock copolymer studied in the bulk. SANS measurements were made both on isotropic a...

  5. 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.

  6. Bisimulation Lattice of Asymmetric Chi Calculus with Mismatch

    Institute of Scientific and Technical Information of China (English)

    Dong Xiaoju(董笑菊); Zhong Farong; Fu Yuxi

    2003-01-01

    This paper carries out a systematic investigation into the bisimulation lattice of asymmetric chi calculus with a mismatch combinator. It is shown that all the sixty three L-bisimilarities collapse to twelve distinct relations and they form a bisimulation lattice with respect to set inclusion. The top of the lattice coincides with the barbed bisimilarity.

  7. Linguistic Correlates of Asymmetric Motor Symptom Severity in Parkinson's Disease

    Science.gov (United States)

    Holtgraves, Thomas; McNamara, Patrick; Cappaert, Kevin; Durso, Raymond

    2010-01-01

    Asymmetric motor severity is common in Parkinson's Disease (PD) and provides a method for examining the neurobiologic mechanisms underlying cognitive and linguistic deficits associated with the disorder. In the present research, PD participants (N = 31) were assessed in terms of the asymmetry of their motor symptoms. Interviews with the…

  8. Farm-gate tomato price negotiations under asymmetric information information

    NARCIS (Netherlands)

    Jaleta Debello, M.; Gardebroek, C.

    2007-01-01

    This article provides an empirical analysis of farm-gate tomato price negotiations under asymmetric information. Regression models are estimated to analyze when and by how much sellers stick to their initial ask prices and what explains the variation in the initial ask¿offer price spread. Detailed i

  9. Uniform versus asymmetric shading mediates crown recession in conifers.

    Directory of Open Access Journals (Sweden)

    Amanda L Schoonmaker

    Full Text Available In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta and shade tolerant white spruce (Picea glauca. We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1, complete uniform shading of the entire tree, (2 light asymmetric shading where the lower 1/4-1/3 of the tree crown was shaded, (3 heavy asymmetric shading as in (2 except with greater light reduction and (4 control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality--mediated by an asymmetry in light exposure of the crown.

  10. [Evaluation of asymmetric implants in breast augmentation surgery].

    Science.gov (United States)

    Fitoussi, A D; Couturaud, B

    2005-10-01

    Since more than 30 years, the quality of breast implants has continued to evolve in order to improve the aesthetic results of prosthetic augmentation. Shapes and materials of these implants have also evolved to obtain stronger and more reliable prostheses almost similar to the natural breast. Therefore it can be considered that the use of asymmetric implants is the last step in implant technology before using made to measure implants. Asymmetric implants allow obtaining different contours in harmony to the different breast shapes capable to reproduce faithfully, in all dimensions, the anatomy of the female breast, including the differences between each side which maximise the naturalness of the result. Such implants have an axis directed towards the exterior and lower part of the chest wall, are wider than high with a thinner part on their inner edge and a concave rear side moulding the curves of the chest wall. In our own experience, we placed between 2002 and 2004, asymmetric implants in 100 patients. Such implants were easy to place and no secondary rotation was observed. The control of secondary displacements even in case of prosthesis change seems to be linked to their concave rear side, roughness and asymmetry. When analysing retrospectively the medical records, no distinctive features were observed when compared to symmetric classic implants in easiness in the surgical procedure or in complications except a slightly higher rate of seroma formation. However asymmetric implants are less appropriate in case of major breast ptosis, patients being unsatisfied by the "too natural" breast shape. Moreover a high risk of secondary rotation seems to be real in such cases. In summary, for all these reasons, asymmetric implants, are gradually considered to be a first-rank choice for implants in breast augmentation cosmetic surgery. PMID:16198044

  11. Asymmetric Inheritance of Mother Versus Daughter Centrosome in Stem Cell Division

    OpenAIRE

    Yamashita, Yukiko M.; Anthony P Mahowald; Perlin, Julie R.; Fuller, Margaret T.

    2007-01-01

    Adult stem cells often divide asymmetrically to produce one self-renewed stem cell and one differentiating cell, thus maintaining both populations. The asymmetric outcome of stem cell divisions can be specified by an oriented spindle and local self-renewal signals from the stem cell niche. Here we show that developmentally programmed asymmetric behavior and inheritance of mother and daughter centrosomes underlies the stereotyped spindle orientation and asymmetric outcome of stem cell division...

  12. Study of Rayleigh-backscattering induced coherence collapse in an asymmetric DFB FL sensor

    Science.gov (United States)

    Liu, Wen; Ma, Lina; Hu, Zhengliang; Feng, Ying; Yang, Huayong

    2016-09-01

    Rayleigh-back scattering induced coherence collapse of an asymmetric distributed feedback fiber laser (DFB FL) sensor is investigated using a composite cavity model. The coherence collapse threshold condition of the asymmetric DFB FL sensor is measured. The DFB FL sensor shows different dynamic behaviors in different pump configurations. According to the asymmetric behavior to the external optical feedback, a novel method to find the actual phase shift position of the asymmetric DFB FL sensor is presented.

  13. Receptance-Based Partial Pole Assignment for Asymmetric Systems Using State-Feedback

    Directory of Open Access Journals (Sweden)

    M. Ghandchi Tehrani

    2012-01-01

    Full Text Available Many structures or machines interact with some internal nonconservative forces and present asymmetric systems in which the stiffness and damping matrices are asymmetric. Examples include friction-induced vibration and aeroelastic flutter. Asymmetric systems are prone to flutter instability as a result of the real parts of some poles becoming positive when certain system parameters vary.

  14. Dual task effects for asymmetric stepping on a split-belt treadmill.

    NARCIS (Netherlands)

    McFadyen, B.J.; Hegeman, J.; Duysens, J.E.J.

    2009-01-01

    Bilaterally asymmetric stepping during walking is common to a number of pathological gaits (e.g., hemiplegia, limping). In the present work, the attention level of asymmetric stepping was studied by having subjects walk on a split-belt treadmill with symmetric (2 km/h) and asymmetric (2 km/h vs 4 km

  15. A Numerical Comparison of Symmetric and Asymmetric Supersonic Wind Tunnels

    Science.gov (United States)

    Clark, Kylen D.

    Supersonic wind tunnels are a vital aspect to the aerospace industry. Both the design and testing processes of different aerospace components often include and depend upon utilization of supersonic test facilities. Engine inlets, wing shapes, and body aerodynamics, to name a few, are aspects of aircraft that are frequently subjected to supersonic conditions in use, and thus often require supersonic wind tunnel testing. There is a need for reliable and repeatable supersonic test facilities in order to help create these vital components. The option of building and using asymmetric supersonic converging-diverging nozzles may be appealing due in part to lower construction costs. There is a need, however, to investigate the differences, if any, in the flow characteristics and performance of asymmetric type supersonic wind tunnels in comparison to symmetric due to the fact that asymmetric configurations of CD nozzle are not as common. A computational fluid dynamics (CFD) study has been conducted on an existing University of Michigan (UM) asymmetric supersonic wind tunnel geometry in order to study the effects of asymmetry on supersonic wind tunnel performance. Simulations were made on both the existing asymmetrical tunnel geometry and two axisymmetric reflections (of differing aspect ratio) of that original tunnel geometry. The Reynolds Averaged Navier Stokes equations are solved via NASAs OVERFLOW code to model flow through these configurations. In this way, information has been gleaned on the effects of asymmetry on supersonic wind tunnel performance. Shock boundary layer interactions are paid particular attention since the test section integrity is greatly dependent upon these interactions. Boundary layer and overall flow characteristics are studied. The RANS study presented in this document shows that the UM asymmetric wind tunnel/nozzle configuration is not as well suited to producing uniform test section flow as that of a symmetric configuration, specifically one

  16. Asymmetric Fabry-Pérot interferometric cavity for fiber optical sensors

    Institute of Scientific and Technical Information of China (English)

    Shaoji Jiang; Youcheng Liang; Xi Zhu; Hezhou Wang

    2006-01-01

    Good linearity and wide dynamic range are the advantages of asymmetric Fabry-Pérot (F-P) interferometric cavity, whose realization has been long for. Based on optical thin film characteristic matrix theory, an asymmetric F-P interferometric cavity with good linearity and wide dynamic range is designed. And by choosing the material of two different thin metallic layers, the asymmetric F-P interferometric cavity is successfully fabricated. The design theory and method of this asymmetric F-P interferometric cavity have been described in detailed. In this paper an asymmetric F-P interferometric cavity used in fiber optical sensor is reported.

  17. High performance of junctionless MOSFET with asymmetric gate

    Science.gov (United States)

    Wang, Ying; Tang, Yan; Sun, Ling-ling; Cao, Fei

    2016-09-01

    In this work, we propose a junctionless MOSFET with asymmetric gates (AG-JL MOSFET). This device is a double gate structure with a lateral offset between the gate, and this leads to different characteristic than a conventional double gate structure. Specifically, the asymmetric gate modulates the effective channel length depending on whether the device is in the ON or OFF state, which this leads to more ideal device characteristics. A comprehensive device performance comparison including the ION/IOFF ratio, subthreshold slope (SS), and drain-induced barrier lowering (DIBL) between the proposed device and a conventional device is presented. The proposed device exhibits superior performance when compared a conventional device, and results show that it is also less sensitive to process variations.

  18. The newest observational evidence on asymmetrical deformation of the Earth

    Institute of Scientific and Technical Information of China (English)

    黄立人; 马宗晋; 朱建新

    2002-01-01

    Based on the coordinates, velocities and their error estimations of 595 GPS, SLR and VLBI stations issued by IERS in March 2001, the current asymmetrical deformation of the Earth is studied. The results show that the northern hemisphere of the Earth is undergoing compressive deformation, and the southern hemisphere is undergoing extensional deformation with the equator as the boundary. If the longitude line of 90(E and 90(W is taken as the boundary, the Pacific hemisphere (with 180( as its central longitude) is undergoing compressive deformation, and the Atlantic hemisphere (with 0( as its central longitude) is undergoing extensional deformation. The deformation patterns indicate again that the Earth is undergoing some dual-asymmetrical deformation. Moreover, taking 6 366.740 km as the standard mean curvature radius of the Earth, the velocity of volume change calculated from the data of space geodesy is 6.65(1011 m3/a.

  19. 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)

  20. Symmetric/asymmetric bifurcation behaviours of a bogie system

    DEFF Research Database (Denmark)

    Xue-jun, Gao; Ying-hui, Li; Yuan, Yue;

    2013-01-01

    Based on the bifurcation and stability theory of dynamical systems, the symmetric/asymmetric bifurcation behaviours and chaotic motions of a railway bogie system under a complex nonlinear wheel–rail contact relation are investigated in detail by the ‘resultant bifurcation diagram’ method...... with slowly increasing and decreasing speed. It is found that the stationary equilibrium solution and the periodic motions coexist due to the sub-critical Hopf bifurcation in the railway bogie system. It is also found that multiple solutions coexist in many speed ranges. The coexistence of multiple solutions...... may result in a jump and hysteresis of the oscillating amplitude for different kinds of disturbances. It should be avoided in the normal operation. Furthermore, it is found that symmetry-breaking of the system through a pitchfork bifurcation leads to asymmetric chaotic motions in the railway bogie...

  1. 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.

  2. Broadband terahertz metamaterial absorber based on sectional asymmetric structures

    Science.gov (United States)

    Gong, Cheng; Zhan, Mingzhou; Yang, Jing; Wang, Zhigang; Liu, Haitao; Zhao, Yuejin; Liu, Weiwei

    2016-01-01

    We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber’s working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber’s each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si3N4 is only 1.9 μm thick. The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging. PMID:27571941

  3. Atomic-Level Understanding of "Asymmetric Twins" in Boron Carbide

    Science.gov (United States)

    Xie, Kelvin Y.; An, Qi; Toksoy, M. Fatih; McCauley, James W.; Haber, Richard A.; Goddard, William A.; Hemker, Kevin J.

    2015-10-01

    Recent observations of planar defects in boron carbide have been shown to deviate from perfect mirror symmetry and are referred to as "asymmetric twins." Here, we demonstrate that these asymmetric twins are really phase boundaries that form in stoichiometric B4C (i.e., B12C3 ) but not in B13C2 . TEM observations and ab initio simulations have been coupled to show that these planar defects result from an interplay of stoichiometry, atomic positioning, icosahedral twinning, and structural hierarchy. The composition of icosahedra in B4C is B11C and translation of the carbon atom from a polar to equatorial site leads to a shift in bonding and a slight distortion of the lattice. No such distortion is observed in boron-rich B13C2 because the icosahedra do not contain carbon. Implications for tailoring boron carbide with stoichiometry and extrapolations to other hierarchical crystalline materials are discussed.

  4. Gamma ray constraints on flavor violating asymmetric dark matter

    DEFF Research Database (Denmark)

    Masina, I.; Panci, P.; Sannino, F.

    2012-01-01

    We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, Fermi and H.E.S.S.; performing combined fits we...... determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by Fermi for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 Te......V. We find that the Fermi constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies....

  5. Localization of Asymmetric Brain Function in Emotion and Depression

    Science.gov (United States)

    Herrington, John D.; Heller, Wendy; Mohanty, Aprajita; Engels, Anna S.; Banich, Marie T.; Webb, Andrew G.; Miller, Gregory A.

    2011-01-01

    Although numerous EEG studies have shown that depression is associated with abnormal functional asymmetries in frontal cortex, fMRI and PET studies have largely failed to identify specific brain areas showing this effect. The present study tested the hypothesis that emotion processes are related to asymmetric patterns of fMRI activity, particularly within dorsolateral prefrontal cortex (DLPFC). Eleven depressed and 18 control participants identified the color in which pleasant, neutral, and unpleasant words were printed. Both groups showed a leftward lateralization for pleasant words in DLPFC. In a neighboring DLPFC area, the depression group showed more right-lateralized activation than controls, replicating EEG findings. These data confirm that emotional stimulus processing and trait depression are associated with asymmetric brain functions in distinct subregions of the DLPFC that may go undetected unless appropriate analytic procedures are used. PMID:20070577

  6. Asymmetrical Information and Public Failure in the Myriad Decision

    Directory of Open Access Journals (Sweden)

    Reginald Shareef

    2014-09-01

    Full Text Available The Public Value concept is a Public Management normative process that utilizes efficiency and ethics as co-equal determinants to assess organizational outcomes. As such, Public Value represents what Ghoshal calls intellectual pluralism or the utilization of normative management processes in the social sciences to challenge the intellectual absolutism of the Chicago School. One discipline where Public Value can be used to assess normative results is Legal Studies’ antitrust field. This research applies Public Value criteria in evaluating the U.S. Supreme Court’s 2013 ruling in Association for Molecular Pathology v. Myriad Genetics. The conclusions tentatively found the Court’s decision will (a create Public Value at the macro level but (b trigger public failure at the micro level for poor women because of an asymmetrical information network. This outcome fits with Stiglitz’s hypothesis concerning asymmetrical information and market failure. Further empirical research on Myriad’s policy is recommended.

  7. Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

    Science.gov (United States)

    Ryan, Michael C; Rao, Meera

    2016-01-01

    Summary A full account of our efforts toward an asymmetric redox bicycloisomerization reaction is presented in this article. Cyclopentadienylruthenium (CpRu) complexes containing tethered chiral sulfoxides were synthesized via an oxidative [3 + 2] cycloaddition reaction between an alkyne and an allylruthenium complex. Sulfoxide complex 1 containing a p-anisole moiety on its sulfoxide proved to be the most efficient and selective catalyst for the asymmetric redox bicycloisomerization of 1,6- and 1,7-enynes. This complex was used to synthesize a broad array of [3.1.0] and [4.1.0] bicycles. Sulfonamide- and phosphoramidate-containing products could be deprotected under reducing conditions. Catalysis performed with enantiomerically enriched propargyl alcohols revealed a matched/mismatched effect that was strongly dependent on the nature of the solvent. PMID:27559366

  8. Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

    Science.gov (United States)

    2016-01-01

    Summary Oxindole scaffolds are prevalent in natural products and have been recognized as privileged substructures in new drug discovery. Several oxindole-containing compounds have advanced into clinical trials for the treatment of different diseases. Among these compounds, enantioenriched 3-hydroxyoxindole scaffolds also exist in natural products and have proven to possess promising biological activities. A large number of catalytic asymmetric strategies toward the construction of 3-hydroxyoxindoles based on transition metal catalysis and organocatalysis have been reported in the last decades. Additionally, 3-hydroxyoxindoles as versatile precursors have also been used in the total synthesis of natural products and for constructing structurally novel scaffolds. In this review, we aim to provide an overview about the catalytic asymmetric synthesis of biologically important 3-substituted 3-hydroxyoxindoles and 3-hydroxyoxindole-based further transformations. PMID:27340490

  9. Multiband Printed Asymmetric Dipole Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    Chia-Mei Peng

    2013-01-01

    Full Text Available The ability of a single layer strip fed printed asymmetric dipole antenna, which is composed of top-loading, asymmetric coplanar waveguide (ACPW and stepped-feeding structure, to operate at three wide frequency bands (698~960 MHz, 1710~2620 MHz, and 5150~5850 MHz to cover WLAN and LTE operation has been demonstrated. A prototype of the proposed antenna with 57.5 mm in length, 0.4 mm in thickness, and 5 mm in width is fabricated and experimentally investigated. The experimental results indicate that the VSWR 2.5 : 1 bandwidths achieved were 74.3%, 40.8%, and 18.2% at 700 MHz, 2450 MHz, and 5500 MHz, respectively. Experimental results are shown to verify the validity of theoretical work.

  10. Elliptic and Triangular flow in asymmetric heavy-ion collisions

    CERN Document Server

    Haque, Md Rihan; Mohanty, Bedangadas

    2011-01-01

    We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu and Au+Si) collisions at \\sqrt_NN = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multi-phase transport (AMPT) model shows that triangularity (\\epsilon_3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (\\epsilon_2), fluctuations in eccentricity and v2 shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.

  11. A computational study of asymmetric glottal jet deflection during phonation.

    Science.gov (United States)

    Zheng, X; Mittal, R; Bielamowicz, S

    2011-04-01

    Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier-Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called "Coanda effect" in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection. PMID:21476669

  12. Particle--asymmetric-rotor descriptions of (105109)Agative parity states

    International Nuclear Information System (INIS)

    The negative parity states of 105109Ag are interpreted according to the generalized particle--asymmetric-rotor model. In particular, the influence of the different Nilsson proton orbitals (lying near the Fermi level) on the theoretical level spectra and electromagnetic properties is investigated in detail. Furthermore, the analysis of the wave functions of the theoretical levels, and the contributions of their main components in the B(M1) and B(E2) matrix elements, reveals the single particle or collective character of such levels. The best agreement between the theoretical and experimental results is obtained by coupling four Nilsson proton orbitals (numbers 10 --13), with main components on p/sub 1/2/, p/sub 3/2/, f/sub 5/2/ subshells, to an asymmetric rotor

  13. ECC over RSA for Asymmetric Encryption-A Review

    Directory of Open Access Journals (Sweden)

    Kamlesh Gupta

    2011-05-01

    Full Text Available Cryptography is used to transmit the data securely in open network. This paper gives the survey of Elliptic Curve Cryptosystem (ECC used in many applications. ECC is a when compared to RSA and discrete logarithm systems, is a better option for the future. For this reason ECC is such an excellent choice for doing asymmetric cryptography in portable devices right now. The smaller ECC keys it turn makes the cryptographic operations that must be performed by the communicating devices to be embedded into considerably smaller hardware, so that software applications may complete cryptographic operations with fewer processor cycles, and operations can be performed much faster, while still retaining equivalent security. This means, in turn, reduced power consumption, less space consumed on the printed circuit board, and software applications that run more rapidly make lower memory demands. In brief, for communication using smaller devices and asymmetric cryptosystem we need ECC.

  14. Asymmetric Dark Matter Models and the LHC Diphoton Excess

    CERN Document Server

    Frandsen, Mads T

    2016-01-01

    The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays of a new spin-0 particle with a sizable diphoton partial width, e.g. induced by new heavy weakly charged particles. These are also key ingredients in models cogenerating asymmetric DM and baryons via sphaleron interactions and an initial particle asymmetry. We explore what consequences the new scalar may have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances.

  15. Asymmetric random matrices: What do we need them for?

    CERN Document Server

    Drozdz, Stanislaw; Ioannides, Andreas A; 10.5506/APhysPolB.42.987

    2011-01-01

    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...

  16. Channel Capacity Limits of Cognitive Radio in Asymmetric Fading Environments

    CERN Document Server

    Suraweera, Himal A; Smith, Peter J; Shafi, Mansoor; Faulkner, Michael

    2008-01-01

    Cognitive radio technology is an innovative radio design concept which aims to increase spectrum utilization by exploiting unused spectrum in dynamically changing environments. By extending previous results, we investigate the capacity gains achievable with this dynamic spectrum approach in asymmetric fading channels. More specifically, we allow the secondary-to-primary and secondary-to-secondary user channels to undergo Rayleigh or Rician fading, with arbitrary link power. In order to compute the capacity, we derive the distributions of ratios of Rayleigh and Rician variables. Compared to the symmetric fading scenario, our results indicate several interesting features of the capacity behaviour under both average and peak received power constraints. Finally, the impact of multiple primary users on the capacity under asymmetric fading has also been studied.

  17. Proline-catalysed asymmetric ketol cyclizations: The template mechanism revisited

    Indian Academy of Sciences (India)

    R Malathi; D Rajagopal; Zoltan G Hajos; S Swaminathan

    2004-03-01

    A modified template mechanism based on modelling studies of energy minimised complexes is presented for the asymmetric proline-catalysed cyclization of triketones 1, 2 and 3 to the 2, 3-ketols 1a, 2a and 3a respectively. The template model involves a three-point contact as favoured in enzyme-substrate interactions. Our minimisation studies are in agreement with the divergent behaviour of the 6,5-, 6,6- and 6,7-bicyclic systems. They support the high 93.4% ee observed with the 6,5-bicyclic ketol and the lower 73% ee found with the 6,6-bicyclic ketol. The calculations also explain the lack of asymmetric induction with the 6,7-bicyclic system.

  18. Deaging and Asymmetric Energy Landscapes in Electrically Biased Ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Tutuncu, Goknur; Damjanovic, Dragan; Chen, Jun; Jones, Jacob L. (Ecole); (UST - China); (Florida)

    2015-09-01

    In ferroic materials, the dielectric, piezoelectric, magnetic, and elastic coefficients are significantly affected by the motion of domain walls. This motion can be described as the propagation of a wall across various types and strengths of pinning centers that collectively constitute a force profile or energetic landscape. Biased domain structures and asymmetric energy landscapes can be created through application of high fields (such as during electrical poling), and the material behavior in such states is often highly asymmetric. In some cases, this behavior can be considered as the electric analogue to the Bauschinger effect. The present Letter uses time-resolved, high-energy x-ray Bragg scattering to probe this asymmetry and the associated deaging effect in the ferroelectric morphotropic phase boundary composition 0.36BiScO{sub 3}-0.64PbTiO{sub 3}.

  19. R & D STRATEGIC INVESTMENT IN AN ASYMMETRICAL CASE

    Institute of Scientific and Technical Information of China (English)

    Minggao XUE; Pu GONG

    2006-01-01

    This article analyzes R & D investment decisions in an asymmetrical case. The investment decisions share three important characteristics. First, the investment is completely irreversible. Second,there are two kinds of uncertainties over the future returns from the investment and over technology in R & D process, respectively. Third, there is strategic competition in the asymmetrical case. This article presents the optimal investment threshold values and the optimal investment rule of high-efficient firm (leader), and shows that the investment threshold values are reduced by competition of two firms.Finally, the mixed investment strategies for two firms, the probability that each firm separately exercises the option to invest, and the probability that two firms simultaneously exercise the option are given in the paper.

  20. Isoscalar dipole transition as a probe for asymmetric clustering

    CERN Document Server

    Chiba, Y; Taniguchi, Y

    2015-01-01

    Background: The sharp $1^-$ resonances with enhanced isoscalar dipole transition strengths are observed in many light nuclei at relatively small excitation energies, but their nature was unclear. Purpose: We show those resonances can be attributed to the cluster states with asymmetric configurations such as $\\alpha$+$^{16}{\\rm O}$. We explain why asymmetric cluster states are strongly excited by the isoscalar dipole transition. We also provide a theoretical prediction of the isoscalar dipole transitions in $^{20}{\\rm Ne}$ and $^{44}{\\rm Ti}$. Method: The transition matrix is analytically derived to clarify the excitation mechanism. The nuclear model calculations by Brink-Bloch wave function and antisymmetrized molecular dynamics are also performed to provide a theoretical prediction for $^{20}{\\rm Ne}$ and $^{44}{\\rm Ti}$. Results: It is shown that the transition matrix is as large as the Weisskopf estimate even though the ground state is an ideal shell model state. Furthermore, it is considerably amplified i...