WorldWideScience

Sample records for fetuin-a attenuates early

  1. A single intraperitoneal injection of bovine fetuin-A attenuates bone resorption in a murine calvarial model of particle-induced osteolysis.

    Science.gov (United States)

    Jablonski, Heidrun; Polan, Christina; Wedemeyer, Christian; Hilken, Gero; Schlepper, Rüdiger; Bachmann, Hagen Sjard; Grabellus, Florian; Dudda, Marcel; Jäger, Marcus; Kauther, Max Daniel

    2017-09-21

    Particle-induced osteolysis, which by definition is an aseptic inflammatory reaction to implant-derived wear debris eventually leading to local bone destruction, remains the major reason for long-term failure of orthopedic endoprostheses. Fetuin-A, a 66kDa glycoprotein with diverse functions, is found to be enriched in bone. Besides being an important inhibitor of ectopic calcification, it has been described to influence the production of mediators of inflammation. Furthermore, a regulatory role in bone metabolism has been assigned. In the present study, the influence of a single dose of bovine fetuin-A, intraperitoneally injected in mice subjected to particle-induced osteolysis of the calvaria, was analyzed. Twenty-eight male C57BL/6 mice, twelve weeks of age, were randomly divided into four groups. Groups 2 and 4 were subjected to ultra-high molecular weight polyethylene (UHMWPE) particles placed on their calvariae while groups 1 and 3 were sham-operated. Furthermore, groups 3 and 4 received a single intraperitoneal injection of 20mg bovine fetuin-A while groups 1 and 2 were treated with physiologic saline. After 14days calvarial bone was qualitatively and quantitatively assessed using microcomputed tomography (μCT) and histomorphometrical approaches. Application of fetuin-A led to a reduction of particle-induced osteolysis in terms of visible osteolytic lesions and eroded bone surface. The reduction of bone thickness and bone volume, as elicited by UHMWPE, was alleviated by fetuin-A. In conclusion, fetuin-A was found to exert an anti-resorptive effect on particle-induced osteolysis in-vivo. Thus, fetuin-A could play a potentially osteoprotective role in the treatment of bone metabolic disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. A hepatic protein, fetuin-A, occupies a protective role in lethal systemic inflammation.

    Directory of Open Access Journals (Sweden)

    Wei Li

    Full Text Available BACKGROUND: A liver-derived protein, fetuin-A, was first purified from calf fetal serum in 1944, but its potential role in lethal systemic inflammation was previously unknown. This study aims to delineate the molecular mechanisms underlying the regulation of hepatic fetuin-A expression during lethal systemic inflammation (LSI, and investigated whether alterations of fetuin-A levels affect animal survival, and influence systemic accumulation of a late mediator, HMGB1. METHODS AND FINDINGS: LSI was induced by endotoxemia or cecal ligation and puncture (CLP in fetuin-A knock-out or wild-type mice, and animal survival rates were compared. Murine peritoneal macrophages were challenged with exogenous (endotoxin or endogenous (IFN-γ stimuli in the absence or presence of fetuin-A, and HMGB1 expression and release was assessed. Circulating fetuin-A levels were decreased in a time-dependent manner, starting between 26 h, reaching a nadir around 24-48 h, and returning towards base-line approximately 72 h post onset of endotoxemia or sepsis. These dynamic changes were mirrored by an early cytokine IFN-γ-mediated inhibition (up to 50-70% of hepatic fetuin-A expression. Disruption of fetuin-A expression rendered animals more susceptible to LSI, whereas supplementation of fetuin-A (20-100 mg/kg dose-dependently increased animal survival rates. The protection was associated with a significant reduction in systemic HMGB1 accumulation in vivo, and parallel inhibition of IFN-γ- or LPS-induced HMGB1 release in vitro. CONCLUSIONS: These experimental data suggest that fetuin-A is protective against lethal systemic inflammation partly by inhibiting active HMGB1 release.

  3. Fetuin-A levels in hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Bariş Onder Pamuk

    2013-01-01

    Full Text Available OBJECTIVE: Fetuin-A is a protein secreted from the liver that inhibits arterial calcification deposition and can contribute to insulin resistance. Hyperthyroidism is also associated with insulin resistance. It is not known whether hyperthyroidism has an effect on fetuin-A levels. METHODS: We measured fetuin-A levels and homeostasis model of assessment-insulin resistance before hyperthyroidism treatment was initiated and after euthyroidism was achieved. A total of 42 patients diagnosed with hyperthyroidism were enrolled in this study. Fetuin-A, insulin, high-sensitivity C-reactive protein, fasting blood glucose, free T3 (fT3, free T4 (fT4, and thyrotropin were measured before and after euthyroidism was established. RESULTS: Basal fasting blood glucose, high-sensitivity C-reactive protein, insulin, c-peptide, homeostasis model of assessment-insulin resistance, fT3, fT4 and fetuin-A levels were significantly decreased after euthyroidism was achieved (Table 1. Basal fasting blood glucose (r:0.407, p:0.008, high-sensitivity C-reactive protein (r:0.523, p<0.0001, insulin (r:0.479, p:0.001, homeostasis model of assessment-insulin resistance (r:0.541, p<0.0001, fT3 (r:0.492, p:0.001 and fT4 (r:0.473, p:0.002 were positively correlated with basal fetuin-A levels. Basal thyrotropin levels were significantly negatively correlated (r:-0.553, p<0.0001 with basal fetuin-A levels. CONCLUSION: Our findings suggest that hyperthyroidism influences fetuin-A levels.

  4. Fetuin-A and type II diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Lamyaa Ismail Ahmed

    2014-01-01

    Conclusion We concluded that fetuin-A may play a role in the pathogenesis of type II DM, and high serum fetuin-A has a strong association with IR and glycemic control in type II diabetic patients. Future studies are recommended to establish the possibility of using fetuin-A as a predictor of insulin resistance in type II diabetic patients.

  5. Fetuin A Concentration in the Second Trimester Amniotic Fluid of Fetuses with Trisomy 21 Appears to Be Lower: Phenotypic Considerations

    Directory of Open Access Journals (Sweden)

    S. Iliodromiti

    2012-01-01

    Full Text Available Objective. We investigated whether the concentration of the glycoprotein fetuin A is altered in the second trimester amniotic fluid of trisomy 21 pregnancies compared with euploid pregnancies. Methods. 25 pregnancies with an extra chromosome 21 were matched for maternal and gestational age with 25 pregnancies with normal karyotype. Levels of fetuin A in amniotic fluid were measured by a commercially available enzyme-linked immunosorbent assay (ELISA kit. Results. The median concentration of fetuin A in amniotic fluid of trisomy 21 pregnancies (5.3 ng/ml was statistically significantly lower (P  value=0.008 compared with that in euploid pregnancies (6.8 ng/mL. Conclusion. Lower levels of fetuin A in trisomy 21 may indicate an association with altered metabolic pathways in this early stage that could potentially be associated with features of the syndrome, such as growth restriction or impaired osteogenesis.

  6. Effects of hemodialysis on serum fetuin-A levels

    Directory of Open Access Journals (Sweden)

    Roman Safranek

    2012-06-01

    Full Text Available Fetuin-A is a calcification inhibitor, negative acute phase response marker and cardiovascular mortality predictor in hemodialysis patients. Low levels of fetuin-A are associated with malnutrition, inflammation, decreased bone mass density, low-turnover bone and use of high calcium concentration dialysate. Hemodialysis procedure (HD has been shown to decrease fetuin-A levels by 20%, probably due to HD-induced inflammation or acute changes in calcium metabolism. The aim of our study was to investigate effects of HD on serum fetuin-A levels. Forty clinically and hemodynamically stable hemodialysis patients (21 females, 68 (38-85 years underwent routine bicarbonate hemodialysis or hemodiafiltration with polysulfone dialyzer. On consecutive HD dialysis solution with different calcium concentration with/without citric acid was used to assess influence of calcium shifts and parathyroid activity on fetuin-A changes during HD. All other parameters of HD were kept constant. Serum fetuin-A, calcium, phosphorus, iPTH, CRP and other biochemical parameters were measured before and after each HD. Our data show that predialysis serum fetuin-A levels have positive correlation with iPTH levels (p<0.05 and tendency to decrease with higher CRP levels. There was no change in fetuin-A levels during HD: 206 (167.1; 231.9 ug/ml before and 208.9 (170.3; 246.3 ug/ml after HD; respectively. When corrected for haemoconcentration, decrease in fetuin-A was only 2.8% (p<0.05. There was also no difference between effect of hemodialysis and hemodia-filtration procedure. The use of different calcium dialysate concentrations had distinct effect on iPTH levels during and after HD, however, we observed no associated changes in fetuin-A levels. The use of dialysate solution with citric acid had no effect on fetuin-A levels. In conclusion, standard bicarbonate HD with polysulfone dialyser and ultrapure dialysate induces only minor changes in fetuin-A and no changes in hsCRP levels

  7. Impact of the adipokine adiponectin and the hepatokine fetuin-A on the development of type 2 diabetes: prospective cohort- and cross-sectional phenotyping studies.

    Directory of Open Access Journals (Sweden)

    Norbert Stefan

    Full Text Available BACKGROUND: Among adipokines and hepatokines, adiponectin and fetuin-A were consistently found to predict the incidence of type 2 diabetes, both by regulating insulin sensitivity. OBJECTIVE: To determine to what extent circulating adiponectin and fetuin-A are independently associated with incident type 2 diabetes in humans, and the major mechanisms involved. METHODS: Relationships with incident diabetes were tested in two cohort studies: within the European Prospective Investigation into Cancer and Nutrition (EPIC-Potsdam study (628 cases and the Nurses' Health Study (NHS; 470 cases. Relationships with body fat compartments, insulin sensitivity and insulin secretion were studied in the Tübingen Lifestyle Intervention Program (TULIP; N = 358. RESULTS: Circulating adiponectin and fetuin-A, independently of several confounders and of each other, associated with risk of diabetes in EPIC-Potsdam (RR for 1 SD: adiponectin: 0.45 [95% CI 0.37-0.54], fetuin-A: 1.18 [1.05-1.32] and the NHS (0.51 [0.42-0.62], 1.35 [1.16-1.58]. Obesity measures considerably attenuated the association of adiponectin, but not of fetuin-A. Subjects with low adiponectin and concomitantly high fetuin-A had the highest risk. Whereas both proteins were independently (both p<1.8×10(-7 associated with insulin sensitivity, circulating fetuin-A (r = -0.37, p = 0.0004, but not adiponectin, associated with insulin secretion in subjects with impaired glucose tolerance. CONCLUSIONS: We provide novel information that adiponectin and fetuin-A independently of each other associate with the diabetes risk. Furthermore, we suggest that they are involved in the development of type 2 diabetes via different mechanisms, possibly by mediating effects of their source tissues, expanded adipose tissue and nonalcoholic fatty liver.

  8. Fetuin-A induces cytokine expression and suppresses adiponectin production.

    Directory of Open Access Journals (Sweden)

    Anita M Hennige

    Full Text Available BACKGROUND: The secreted liver protein fetuin-A (AHSG is up-regulated in hepatic steatosis and the metabolic syndrome. These states are strongly associated with low-grade inflammation and hypoadiponectinemia. We, therefore, hypothesized that fetuin-A may play a role in the regulation of cytokine expression, the modulation of adipose tissue expression and plasma concentration of the insulin-sensitizing and atheroprotective adipokine adiponectin. METHODOLOGY AND PRINCIPAL FINDINGS: Human monocytic THP1 cells and human in vitro differenttiated adipocytes as well as C57BL/6 mice were treated with fetuin-A. mRNA expression of the genes encoding inflammatory cytokines and the adipokine adiponectin (ADIPOQ was assessed by real-time RT-PCR. In 122 subjects, plasma levels of fetuin-A, adiponectin and, in a subgroup, the multimeric forms of adiponectin were determined. Fetuin-A treatment induced TNF and IL1B mRNA expression in THP1 cells (p<0.05. Treatment of mice with fetuin-A, analogously, resulted in a marked increase in adipose tissue Tnf mRNA as well as Il6 expression (27- and 174-fold, respectively. These effects were accompanied by a decrease in adipose tissue Adipoq mRNA expression and lower circulating adiponectin levels (p<0.05, both. Furthermore, fetuin-A repressed ADIPOQ mRNA expression of human in vitro differentiated adipocytes (p<0.02 and induced inflammatory cytokine expression. In humans in plasma, fetuin-A correlated positively with high-sensitivity C-reactive protein, a marker of subclinical inflammation (r = 0.26, p = 0.01, and negatively with total- (r = -0.28, p = 0.02 and, particularly, high molecular weight adiponectin (r = -0.36, p = 0.01. CONCLUSIONS AND SIGNIFICANCE: We provide novel evidence that the secreted liver protein fetuin-A induces low-grade inflammation and represses adiponectin production in animals and in humans. These data suggest an important role of fatty liver in the pathophysiology of insulin resistance and

  9. The Effects of Fetuin-A Levels on Aortic Stenosis

    Directory of Open Access Journals (Sweden)

    Ahmet Tutuncu

    2014-12-01

    Full Text Available Aim: We aimed to investigate the relation between fetuin-A and calcific aortic stenosis in non diabetic patients whose renal function were normal. Material and Method: 26 patients followed for aortic stenosis by our cardiology clinic for outpatients and 25 voluntary healthy subjects were included in the study. The fetuin%u2013A levels were measured from the venous blood samples of the study population. All patients underwent transthorasic echocardiography, the aortic valvular area and left ventricular parameters of the patients were measured. Results: The average age of the patients in degenerative aortic stenosis group was significantly higher than the control group. The parameters related to aortic valve were naturally higher in patients with dejenerative aortic valve. There was no siginificant difference between two groups about fetuin-A levels. Further more there was no significant relation between fetuin-a levels and aortic stenosis severity. Discussion: In conclusion fetuin-A is a multifunctional glycoprotein that plays important role in systemic calcification inhibition and valvular calcification. Finally aortic stenosis is an active process and larger studies that investigate the relation between fetuin-a and the progression and prognosis of aortic stenosis are needed.

  10. Serum fetuin-A and recurrent urolithiasis in young adults

    Directory of Open Access Journals (Sweden)

    Domenico Prezioso

    2013-12-01

    Full Text Available Objective: Recurrence of urolithiasis is frequent. There are no reliable markers able to indicate recurrent stone former patients. Fetuin-A inhibits hydroxyapatite crystals formation and expansion. This study aims at evaluating whether serum fetuin-A may predict recurrent urolithiasis in young adults. Materials and methods: This is a multicentre study. Young adults patients with recurrent urolithiasis attending 3 urology clinics were enrolled from July 2011 to December 2012. Inclusion criteria were: age 18-40 years, presence of more than one kidney stone. Exclusion criteria were: diabetes mellitus, metabolic disorders, obesity, hypertension, cardiovascular disease, infection diseases. Controls were participants without history of urolithiasis and currently undetected stones. Routine biochemistry, serum concentration of oxalate, fetuin-A, and parathyroid hormone (PTH were assessed; 24/h urinary excretion of creatinine, uric acid, calcium, sodium, phosphorus, potassium, magnesium, glucose, oxalate, amylase, and protein was measured. Kidney ultrasonography and plain X-ray examination was performed. Results: The total cohort was represented by 120 young adults participants (90 patients, and 30 controls. Clinical characteristics were not different between patients and controls. No significant differences were found in serum concentrations as well as in 24/h urinary excretion of recorded variables. No significant difference was found in serum concentration of fetuin-A (median 35.1 ± 18.62 SD Vs 35.12 ± 14.12, μg/ml; p = 0,908. Conclusions: The data of present study do not substantiate the hypothesis that serum fetuin-A may be a reliable predictor of recurrent urolithiasis in young adults.

  11. Patients with dental calculus have increased saliva and gingival crevicular fluid fetuin-A levels but no association with fetuin-A polymorphisms.

    Science.gov (United States)

    Doğan, Gülnihal Emrem; Demir, Turgut; Laloğlu, Esra; Sağlam, Ebru; Aksoy, Hülya; Yildirim, Abdulkadir; Akçay, Fatih

    2016-12-22

    Fetuin-A is a potent inhibitor of calcium-phosphate precipitation and of the calcification process, therefore it can also be related with dental calculus. Thus, we aimed to investigate a possible relationship between fetuin-A gene polymorphism and the presence of dental calculus. A possible relationship between serum, saliva and gingival crevicular fluid (GCF) levels of fetuin-A was also investigated. Fetuin-A c.742C > T and c.766C > G polymorphisms were investigated in 103 patients with or without dental calculus. Additionally, serum, saliva and GCF fetuin-A levels of patients were compared according to dental calculus presence. A significant difference was not observed in the distribution of the fetuin-A c.742C > T and c.766C > G polymorphisms between patients with or without dental calculus. Saliva and GCF fetuin-A concentrations of patients with dental calculus were statistically higher than those without dental calculus (P=0.001, P=0.036 respectively). According to our results, fetuin-A c.742C > T and c.766C > G polymorphisms were not associated with presence of dental calculus. However, higher GCF and saliva fetuin-A levels were detected in patients with dental calculus than in patients without dental calculus, which may result from an adaptive mechanism to inhibit mineral precipitation and eventually calculus formation.

  12. Accelerated growth plate mineralization and foreshortened proximal limb bones in fetuin-A knockout mice.

    Science.gov (United States)

    Seto, Jong; Busse, Björn; Gupta, Himadri S; Schäfer, Cora; Krauss, Stefanie; Dunlop, John W C; Masic, Admir; Kerschnitzki, Michael; Zaslansky, Paul; Boesecke, Peter; Catalá-Lehnen, Philip; Schinke, Thorsten; Fratzl, Peter; Jahnen-Dechent, Willi

    2012-01-01

    The plasma protein fetuin-A/alpha2-HS-glycoprotein (genetic symbol Ahsg) is a systemic inhibitor of extraskeletal mineralization, which is best underscored by the excessive mineral deposition found in various tissues of fetuin-A deficient mice on the calcification-prone genetic background DBA/2. Fetuin-A is known to accumulate in the bone matrix thus an effect of fetuin-A on skeletal mineralization is expected. We examined the bones of fetuin-A deficient mice maintained on a C57BL/6 genetic background to avoid bone disease secondary to renal calcification. Here, we show that fetuin-A deficient mice display normal trabecular bone mass in the spine, but increased cortical thickness in the femur. Bone material properties, as well as mineral and collagen characteristics of cortical bone were unaffected by the absence of fetuin-A. In contrast, the long bones especially proximal limb bones were severely stunted in fetuin-A deficient mice compared to wildtype littermates, resulting in increased biomechanical stability of fetuin-A deficient femora in three-point-bending tests. Elevated backscattered electron signal intensities reflected an increased mineral content in the growth plates of fetuin-A deficient long bones, corroborating its physiological role as an inhibitor of excessive mineralization in the growth plate cartilage matrix--a site of vigorous physiological mineralization. We show that in the case of fetuin-A deficiency, active mineralization inhibition is a necessity for proper long bone growth.

  13. Direct inhibitory effects of pioglitazone on hepatic fetuin-A expression.

    Directory of Open Access Journals (Sweden)

    Akinobu Ochi

    Full Text Available Fetuin-A, a circulating glycoprotein synthesized in the liver, is involved in insulin resistance and type 2 diabetes. However, regulation of fetuin-A synthesis has remained obscure. We previously reported that pioglitazone treatment significantly reduced serum fetuin-A levels in patients with type 2 diabetes. To clarify whether pioglitazone can directory inhibit hepatic fetuin-A synthesis, we investigated the effects of pioglitazone on fetuin-A expression both in vitro and in vivo. Pioglitazone treatment suppressed mRNA and protein expression of fetuin-A in Fao hepatoma cells. Interestingly, rosiglitazone but not metformin, also inhibited fetuin-A expression. In addition, GW 9662, an inhibitor of peroxisome proliferator-activated receptor (PPAR γ, reversed pioglitazone-induced suppression of fetuin-A, suggesting that thiazolidinedione derivatives may have common characteristics with regard to fetuin-A suppression, possibly through PPARγactivation. Finally, oral administration of pioglitazone to mice for 8 weeks resulted in suppression of hepatic fetuin-A mRNA. These findings suggest that pioglitazone may partially ameliorate insulin resistance through its direct inhibitory effects on fetuin-A expression in the liver.

  14. Direct inhibitory effects of pioglitazone on hepatic fetuin-A expression.

    Science.gov (United States)

    Ochi, Akinobu; Mori, Katsuhito; Emoto, Masanori; Nakatani, Shinya; Morioka, Tomoaki; Motoyama, Koka; Fukumoto, Shinya; Imanishi, Yasuo; Koyama, Hidenori; Ishimura, Eiji; Inaba, Masaaki

    2014-01-01

    Fetuin-A, a circulating glycoprotein synthesized in the liver, is involved in insulin resistance and type 2 diabetes. However, regulation of fetuin-A synthesis has remained obscure. We previously reported that pioglitazone treatment significantly reduced serum fetuin-A levels in patients with type 2 diabetes. To clarify whether pioglitazone can directory inhibit hepatic fetuin-A synthesis, we investigated the effects of pioglitazone on fetuin-A expression both in vitro and in vivo. Pioglitazone treatment suppressed mRNA and protein expression of fetuin-A in Fao hepatoma cells. Interestingly, rosiglitazone but not metformin, also inhibited fetuin-A expression. In addition, GW 9662, an inhibitor of peroxisome proliferator-activated receptor (PPAR) γ, reversed pioglitazone-induced suppression of fetuin-A, suggesting that thiazolidinedione derivatives may have common characteristics with regard to fetuin-A suppression, possibly through PPARγactivation. Finally, oral administration of pioglitazone to mice for 8 weeks resulted in suppression of hepatic fetuin-A mRNA. These findings suggest that pioglitazone may partially ameliorate insulin resistance through its direct inhibitory effects on fetuin-A expression in the liver.

  15. Patients with nephrolithiasis had lower fetuin-A protein level in urine and renal tissue.

    Science.gov (United States)

    Wu, Yong Xian; Li, Cheng Yang; Deng, Yao Liang

    2014-02-01

    Fetuin-A acts as an inhibitor of systemic and local ectopic calcification and inflammatory response, but the role of fetuin-A in the etiology of urolithiasis is still unclear. We aim to investigate the expression of fetuin-A in the serum, urine and renal tissue of patients with or without nephrolithiasis. 48 patients with nephrolithiasis (group A) and 32 individuals without urolithiasis (group B, control group) were enrolled into our study. Level of fetuin-A in serum and urine was measured by ELISA, and expression of fetuin-A in renal tissue was localized and assessed by immunohistochemistry, real-time polymerase chain reaction, and Western blotting, respectively. Indexes of oxidative stress in kidney were evaluated. Other routine serum and urine chemistries for inpatients were measured biochemically. The results showed that fetuin-A expressed widely in the proximal and distal renal tubule, the thin segment of Henle's loop and the collecting duct epithelium. There were no differences in serum fetuin-A level between the two groups. Compared with control group, cellular expression of P47phox and fetuin-A mRNAs in the renal tissue of patients with nephrolithiasis increased, the level of MDA in renal tissue and the level of urinary calcium also increased, but urinary and renal fetuin-A protein and the activities of SOD in renal tissue decreased. Correlation analysis showed that there was a negative correlation between the level of renal fetuin-A protein and the expression of P47phox mRNA and MDA. These results revealed that nephrolithiasis patients had lower fetuin-A protein level in urine and renal tissue.

  16. Factors associated with serum fetuin-A concentrations after long-term use of different phosphate binders in hemodialysis patients

    National Research Council Canada - National Science Library

    Lin, Hsin-Hung; Liou, Hung-Hsiang; Wu, Ming-Shiou; Huang, Chiu-Ching

    2016-01-01

    Fetuin-A is known as a circulating inhibitor of vascular calcification. Factors associated with serum fetuin-A concentrations after long-term use of different phosphate binders in hemodialysis patients is still uncertain...

  17. Serum Fetuin-A levels, insulin resistance and oxidative stress in women with polycystic ovary syndrome.

    Science.gov (United States)

    Enli, Yasar; Fenkci, Semin Melahat; Fenkci, Veysel; Oztekin, Ozer

    2013-12-01

    This study was designed to determine serum Fetuin-A levels and establish whether serum Fetuin-A level is related with insulin resistance, oxidative stress, ovarian hyperandrogenism and dyslipidemia in women with polycystic ovary syndrome (PCOS). Twenty-two patients with PCOS and twenty-one healthy control women were evaluated in this controlled clinical study. Serum Fetuin-A, lipid fractions, glucose, insulin, malondialdehyde (MDA), myeloperoxidase (MPO), glutathione (GSH), superoxide dismutase (SOD) and other hormone (gonadotropins, androgens) levels were measured. The estimate of insulin resistance was calculated by homeostasis model assessment (HOMA-R). The women with PCOS had significantly higher serum fasting glucose, insulin, luteinizing hormone (LH), MDA, Fetuin-A levels, and LH/follicle-stimulating hormone (FSH) ratio, free androgen index (FAI), HOMA-IR than healthy women. However, sex hormone-binding globulin (SHBG) and GSH levels were significantly lower in patients with PCOS compared with controls. Fetuin-A was positively correlated with insulin, HOMA-IR and FAI. Multiple regression analysis revealed that FAI was strong predictor of serum Fetuin-A level. Serum Fetuin-A level was related with insulin resistance and ovarian hyperandrogenism in women with PCOS. These results suggest that Fetuin-A may have a role in triggering the processes leading to insulin resistance and androgen excess in PCOS.

  18. The role of fetuin-A in physiological and pathological mineralization.

    Science.gov (United States)

    Brylka, Laura; Jahnen-Dechent, Willi

    2013-10-01

    Mineralization in higher vertebrates is restricted to bones and teeth. Pathological calcification is mostly known in vasculature but can basically affect all soft tissues. Simply put, tissue mineralization occurs through the interplay of three key determinants: extracellular matrix suitable for mineralization, extracellular levels of inorganic phosphate and calcium, and the levels of mineralization inhibitors that may be expressed systemically or locally. In this article we describe the role of a prototypic systemic inhibitor protein of mineralization, the hepatic plasma protein α2-Heremans-Schmid glycoprotein/fetuin-A. Fetuin-A mediates the formation of stable colloidal mineral-protein complexes called calciprotein particles (CPPs). Thus, fetuin-A is important in the stabilization and clearance of amorphous mineral precursor phases. Efficient clearance of CPPs and, thus, of excess mineral from circulation prevents local buildup of mineral and calcification of soft tissue. Besides calcium phosphate binding, fetuin-A also acts as a carrier for lipids, which may influence calcification, inflammation, and apoptosis. Fetuin-A-deficient (Ahsg(-/-)) mice show impaired growth of their long bones and premature growth plate closure. We posit that the absence of fetuin-A in the growth plate causes simultaneous lack of calcification inhibition and excess lipid hormone signaling, leading to premature growth plate mineralization and shortened long bones. This suggests that fetuin-A regulates endochondral ossification through mineralization inhibition and lipid (hormone) binding.

  19. Relationship Between Fetuin-A Level and Cardiovascular Risk Factors in Peritoneal Dialysis Patients

    Directory of Open Access Journals (Sweden)

    Çubukçuoğlu, Tarık

    2013-01-01

    Full Text Available OBJECTIVE: Vascular calcifications and chronic inflammation are the main reasons of the decreased life span and prevalent morbidity for patients on renal replacement therapy due to chronic renal failure. Scoring systems used to determine the chance of cardiovascular (CV risk and traditional CV risk factors frequently fail to identify the risk in these patients. New markers to predict the risk of CV disease continues to be investigated. One of the most studied marker in recent years is a serum glycoprotein fetuin-A, which is major calcification inhibitor. We aimed to study the relation between fetuin-A subclinical inflammation and cardiovascular risk factors in Peritoneal Dialysis (PD patients and healthy volunteers.MATERIAL and METHODS: Forty-eight PD patients and 27 healthy volunteers were included in the study. Fetuin-A levels, body weight, body mass index, blood pressure, markers of inflammation (sedimentation, C-reactive protein, ferritin and lipid profile tests were performed. The relationship between these parameters was compared with fetuin-A.RESULTS: CRP and sedimentation levels were significantly higher in the group of PD patients. Fetuin-A levels were significantly lower in PD patients than the control group. There was a negative correlation between serum fetuin-A levels, average arterial blood pressure and CRP.CONCLUSION: Fetuin-A can be used to predict subclinic inflammation, and cardiovascular mortality risk in PD patients.

  20. Is rationale to decrease serum osteoprotegerin and fetuin-A in type 2 diabetes mellitus patients?

    Science.gov (United States)

    Berezin, Alexander

    2016-01-01

    Fetuin-A and osteoprotegerin (OPG) are considered biomarkers of atherosclerosis, vascular calcification, inflammation in subjects with type 2 diabetes mellitus (T2DM) with possible predictive value. Recent clinical studies have been shown that fetuin-A and OPG could be helpful for cardiovascular risk stratification in T2DM. Therefore, fetuin-A and OPG may offer protection against atherosclerosis and vascular calcification. However, clinical implication of decreased serum concentrations of these biomarkers in T2DM during treatment with thiazolidinediones, in particular pioglitazone, and metformin is not fully understood. The relation of thiazolidinediones- and metformin- induced post-treatment serum levels of fetuin-A and OPG to changes in CV risk requires more investigations.

  1. The serum glycoprotein fetuin-A promotes Lewis lung carcinoma tumorigenesis via adhesive-dependent and adhesive-independent mechanisms.

    Science.gov (United States)

    Kundranda, Madappa N; Henderson, Melodie; Carter, Kathy J; Gorden, Lee; Binhazim, Awadh; Ray, Sanhita; Baptiste, Trevor; Shokrani, Masih; Leite-Browning, Maria L; Jahnen-Dechent, Willi; Matrisian, Lynn M; Ochieng, Josiah

    2005-01-15

    Fetuin-A is a serum glycoprotein in the cystatin family associated with the regulation of soft tissue calcification. We tested the role of systemic fetuin in tumor cell growth and metastasis by injecting Lewis lung carcinoma (LLC) cells into fetuin-A null and their wild-type (WT) littermate control C57BL/6 mice via the tail vein, s.c., and intrasplenic routes. In the experimental metastasis assay, the lungs of the WT mice were filled with metastatic nodules, whereas the lungs of the fetuin-A null mutant mice were virtually free of colonies at the end of 2 weeks. Lung colonization responded to the levels of serum fetuin-A in a dose-dependent manner, as observed by the formation of half as many colonies in mice heterozygous for the fetuin-A locus compared with homozygous WT mice and restoration of lung colonization by the administration of purified fetuin-A to fetuin-A-null mice. Serum fetuin-A also influenced the growth of LLC cells injected s.c.: fetuin-A-null mice developed small s.c. tumors only after a substantial delay. Similarly, intrasplenic injection of LLC cells resulted in rapid colonization of the liver with metastasis to the lungs within 2 weeks in the WT but not fetuin-A null mice. To examine the mechanism by which fetuin-A influences LLC colonization and growth, we showed that LLC tumor cells adhere to fetuin-A in a Ca(2+)-dependent fashion, resulting in growth of the tumor cells. These studies support the role of fetuin-A as a major growth promoter in serum that can influence tumor establishment and growth.

  2. Serum and Aqueous Humor Levels of Fetuin-A in Pseudoexfoliation Syndrome.

    Science.gov (United States)

    Yuksel, Nilay; Takmaz, Tamer; Ozel Turkcu, Ummuhani; Ergin, Merve; Altinkaynak, Hasan; Bilgihan, Ayse

    2017-06-16

    To evaluate serum and aqueous humor levels of fetuin-A in patients with pseudoexfoliation syndrome (PEXS) in comparison with those of age- and sex-matched healthy subjects. This prospective study included 25 patients with PEXS and 25 control subjects who were undergoing cataract surgery without any systemic or ocular disease. Aqueous humor and serum fetuin-A levels were measured with enzyme-linked immunosorbent assay method. The mean age of the PEXS group (14 males, 11 females, n = 25) was 57.7 ± 6.9 years, and the control group (13 males, 12 females, n = 25) was 58.1 ± 5.7 years. There was no difference between the groups in terms of age (p = 0.77) and sex (p = 0.83). The mean serum fetuin-A level of the PEXS group did not differ from that of the control group (p = 0.53). The mean aqueous humor level of the PEXS group was significantly higher than that of the control group (p = 0.032). There were no significant correlations between aqueous humor and serum fetuin-A levels among patients with PEXS and control group (p > 0.05). Increased levels of fetuin-A in aqueous humor of patients with PEXS may show the local effect of fetuin-A on the anterior segment. With considering the wide range of possible biological functions of fetuin-A in the pathogenesis of PEXS, further studies are needed to clarify the clinical relevance of these findings.

  3. Plasma Fetuin-A concentration, genetic variation in the AHSG gene and risk of colorectal cancer

    DEFF Research Database (Denmark)

    Nimptsch, Katharina; Aleksandrova, Krasimira; Boeing, Heiner

    2015-01-01

    .93-1.22) in women, 1.13 (1.00-1.27) for colon cancer and 1.12 (0.94-1.32) for rectal cancer. To improve causal inference in a Mendelian Randomization approach, five tagging single nucleotide polymorphisms of the AHSG gene were genotyped in a subset of 456 case-control pairs. The AHSG allele-score explained 21......% of the interindividual variation in plasma fetuin-A concentrations. In instrumental variable analysis, genetically raised fetuin-A was not associated with colorectal cancer risk (relative risk per 40 µg/mL genetically determined higher fetuin-A was 0.98, 95% confidence interval: 0.73-1.33). The findings of our study...

  4. Efficiency of Fetuin-A and Procalcitonin in the Diagnosis of Infection in Patients with Febrile Seizure

    Directory of Open Access Journals (Sweden)

    Al-Hakeim Hussein Kadhem

    2016-03-01

    Full Text Available Fetuin-A is a negative acute phase reactant, while procalcitonin is an indicator of severe bacterial infection. Diagnosis of bacterial infection in febrile seizure (FS is important for choosing the most suitable treatment. In this study, serum fetuin-A was estimated, for the first time, in the inpatients with FS and compared with procalcitonin and blood culture tests.

  5. Lower fetuin-A, retinol binding protein 4 and several metabolites after gastric bypass compared to sleeve gastrectomy in patients with type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Mia Jüllig

    Full Text Available BACKGROUND: Bypass of foregut secreted factors promoting insulin resistance is hypothesized to be one of the mechanisms by which resolution of type 2 diabetes (T2D follows roux-en-y gastric bypass (GBP surgery. AIM: To identify insulin resistance-associated proteins and metabolites which decrease more after GBP than after sleeve gastrectomy (SG prior to diabetes remission. METHODS: Fasting plasma from 15 subjects with T2D undergoing GBP or SG was analyzed by proteomic and metabolomic methods 3 days before and 3 days after surgery. Subjects were matched for age, BMI, metformin therapy and glycemic control. Insulin resistance was calculated using homeostasis model assessment (HOMA-IR. For proteomics, samples were depleted of abundant plasma proteins, digested with trypsin and labeled with iTRAQ isobaric tags prior to liquid chromatography-tandem mass spectrometry analysis. Metabolomic analysis was performed using gas chromatography-mass spectrometry. The effect of the respective bariatric surgery on identified proteins and metabolites was evaluated using two-way analysis of variance and appropriate post-hoc tests. RESULTS: HOMA-IR improved, albeit not significantly, in both groups after surgery. Proteomic analysis yielded seven proteins which decreased significantly after GBP only, including Fetuin-A and Retinol binding protein 4, both previously linked to insulin resistance. Significant decrease in Fetuin-A and Retinol binding protein 4 after GBP was confirmed using ELISA and immunoassay. Metabolomic analysis identified significant decrease of citrate, proline, histidine and decanoic acid specifically after GBP. CONCLUSION: Greater early decrease was seen for Fetuin-A, Retinol binding protein 4, and several metabolites after GBP compared to SG, preceding significant weight loss. This may contribute to enhanced T2D remission observed following foregut bypass procedures.

  6. Gomisin J Inhibits Oleic Acid-Induced Hepatic Lipogenesis by Activation of the AMPK-Dependent Pathway and Inhibition of the Hepatokine Fetuin-A in HepG2 Cells.

    Science.gov (United States)

    Kim, Myungsuk; Lim, Sue Ji; Lee, Hee-Ju; Kim, Sun Young; Nho, Chu Won

    2015-11-11

    The aim of our study is to investigate the molecular mechanism of gomisin J from Schisandra chinensis on the oleic acid (OA)-induced lipid accumulation in HepG2 cells. Gomisin J attenuated lipid accumulation in OA-induced HepG2 cells. It also suppressed the expression of lipogenic enzymes and inflammatory mediators and increased the expression of lipolytic enzymes in OA-induced HepG2 cells. Furthermore, the use of specific inhibitors and fetuin-A siRNA and liver kinase B1 (LKB1) siRNA transfected cells demonstrated that gomisin J regulated lipogenesis and lipolysis via inhibition of fetuin-A and activation of an AMP-activated protein kinase (AMPK)-dependent pathway in HepG2 cells. Our results showed that gomisin J suppressed lipid accumulation by regulating the expression of lipogenic and lipolytic enzymes and inflammatory molecules through activation of AMPK, LKB1, and Ca(2+)/calmodulin-dependent protein kinase II and inhibition of fetuin-A in HepG2 cells. This suggested that gomisin J has potential benefits in treating nonalcoholic fatty liver disease.

  7. Serum fetuin A concentration is elevated in children with non-alcoholic fatty liver disease.

    Science.gov (United States)

    Lebensztejn, Dariusz M; Białokoz-Kalinowska, Irena; Kłusek-Oksiuta, Monika; Tarasów, Eugeniusz; Wojtkowska, Małgorzata; Kaczmarski, Maciej

    2014-03-01

    To assess the serum fetuin A concentration as a potential marker of subclinical atherosclerosis in obese children with NAFLD. A prospective analysis of 45 obese children initially diagnosed with liver pathology (elevated serum ALT activity and/or ultrasonographic liver brightness and/or hepatomegaly) was conducted. The diagnosis of NAFLD was established in the children with elevated serum ALT activity and liver steatosis on ultrasound examination. Viral hepatitis, autoimmune, metabolic liver diseases (Wilson disease, alpha-1-antitrypsin deficiency, cystic fibrosis) and drug and toxin-induced liver injury were excluded in all children. The degree of liver steatosis was graded according to Saverymuttu scale and the total liver lipids concentration was assessed using proton magnetic resonance spectroscopy ((1)H MRS). Serum fetuin A concentration was significantly higher in examined children compared to the control group (n=30) (p=0.00002). Higher serum fetuin A concentration was also observed in children with NAFLD (n=19) in comparison to the controls (p=0.000026). Additionally, higher BMI values, waist circumferences, ALT and GGT activity, intensity of liver steatosis on ultrasound and total concentration of lipids in the liver in (1)H MRS were found in children with NAFLD compared to the rest of the examined obese patients (n=26). There was not found any correlation of the investigated glycoprotein with any other assessed parameters both in children with NAFLD and obese children without NAFLD. Higher serum fetuin A concentration found in children with NAFLD compared to the control group support the hypothesis that atherosclerotic processes may develop faster in hepatopatic obese patients. Copyright © 2014 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  8. A highly-sensitive multisubstrate-compatible chemiluminescent immunoassay for human fetuin A

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Sandeep Kumar Vashist ### Abstract We report a highly-sensitive chemiluminescent immunoassay (CIA) for the detection of human fetuin A (HFA), which is based on the leach-proof covalent crosslinking of anti-HFA capture antibodies on 3-aminopropyltriethoxysilane (APTES)-functionalized 96-well chemiluminescent microtiter plates (CMTP) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysulfosuccinimide. It has more than 3-fold reduced overall assay du...

  9. Relationship of apelin, procalcitonin, and fetuin-A concentrations with carotid intima-media thickness in acromegaly.

    Science.gov (United States)

    Topsakal, S; Akin, F; Turgut, S; Yaylali, G F; Herek, D; Ayada, C

    2015-07-01

    Acromegaly is characterized by excess growth hormone and insulin-like growth factor-1 concentrations. There is conflicting evidence as to whether acromegaly is associated with an increased risk of atherosclerosis. Apelin is an adipose tissue-derived peptide that may be associated with hyperinsulinemia. Fetuin-A is a hepatocyte produced plasma glycoprotein that has an important role as a calcification inhibitor. The aim of this study was to examine apelin, fetuin-A, and procalcitonin concentrations and to assess their relationship with carotid intima medial thickness (cIMT) in subjects with acromegaly. Apelin, fetuin-A, and procalcitonin serum concentrations were measured in 37 (20 inactive and 17 active) subjects with acromegaly and 30 control subjects, along with carotid intima medial thickness. The concentrations of apelin, fetuin-A, and procalcitonin were increased in subjects with acromegaly. There were significant correlations between apelin, fetuin-A, and procalcitonin in subjects with acromegaly. Carotid intima medial thickness values were similar between control subjects and subjects with acromegaly. Carotid intima medial thickness was not increased in subjects with acromegaly. It is possible that the increased apelin and fetuin-A concentrations observed play a protective role against the development of atherosclerosis in subjects with acromegaly. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  10. The expression of Fetuin-A in brain tissues of WAG/Rij Rats, genetic rat model of absence epilepsy

    Directory of Open Access Journals (Sweden)

    Ramazan Yüksel

    2015-12-01

    Full Text Available Objective: In the present study, we aimed to determine the Fetuin-A levels in different regions of the brain in absence epileptic Wistar Albino Glaxo/Rijswijk (WAG/Rij rats in order to contribute the identification of new potential biomarkers of the diagnosis, prognosis and follow up the epilepsy treatment. Methods: 1, 3 and 6 months old male WAG/Rij rats (n=21 with absence epilepsy were used in this study. All of the rats were decapitated under anesthesia and their cortex and thalamus tissues were isolated. Fetuin-A levels of the groups were determined by Western Blot method by using standard techniques and differences between densities of the groups were compared. Results: According to data obtained, there was no Fetuin-A expression in brain cortex and thalamus tissues of WAG/Rij rats with absence epilepsy. Conclusion: In this study, it was shown that Fetuin-A is not expressed in brain cortex and thalamus tissues of WAG/Rij rats with absence epilepsy throughout the age-related development. By evaluating the findings obtained, extensive researches that contain molecular and histological methods must be planned, Fetuin-A findings that are obtained experimentally must be confirmed. J Clin Exp Invest 2015; 6 (4: 387-390

  11. Urinary fetuin-A is a novel marker for diabetic nephropathy in type 2 diabetes identified by lectin microarray.

    Directory of Open Access Journals (Sweden)

    Kentaro Inoue

    Full Text Available We analyzed the urine samples of patients with type 2 diabetes at various stages of diabetic nephropathy by lectin microarray to identify a biomarker to predict the progression of diabetic nephropathy. Japanese patients with type 2 diabetes at various stages of nephropathy were enrolled and we performed lectin microarray analyses (n = 17 and measured urinary excretion of fetuin-A (n = 85. The increased signals of urine samples were observed in Siaα2-6Gal/GalNAc-binding lectins (SNA, SSA, TJA-I during the progression of diabetic nephropathy. We next isolated sialylated glycoproteins by using SSA-lectin affinity chromatography and identified fetuin-A by liquid chromatography-tandem mass spectrometer. Urinary excretion of fetuin-A significantly increased during the progression of albuminuria (A1, 0.40 ± 0.43; A2, 0.60 ± 0.53; A3 1.57 ± 1.13 ng/gCr; p = 7.29 × 10(-8 and of GFR stages (G1, 0.39 ± 0.39; G2, 0.49 ± 0.45; G3, 1.25 ± 1.18; G4, 1.34 ± 0.80 ng/gCr; p = 3.89 × 10(-4. Multivariate logistic regression analysis was employed to assess fetuin-A as a risk for diabetic nephropathy with microalbuminuria or GFR<60 mL/min. Fetuin-A is demonstrated as a risk factor for both microalbuminuria and reduction of GFR in diabetic nephropathy with the odds ratio of 4.721 (1.881-11.844 and 3.739 (1.785-7.841, respectively. Collectively, the glycan profiling analysis is useful method to identify the urine biomarkers and fetuin-A is a candidate to predict the progression of diabetic nephropathy.

  12. Effect of moderate alcohol consumption on fetuin-A levels in men and women: post-hoc analyses of three open-label randomized crossover trials

    NARCIS (Netherlands)

    Joosten, M.M.; Schrieks, I.C.; Hendriks, H.F.J.

    2014-01-01

    Background Fetuin-A, a liver-derived glycoprotein that impairs insulin-signalling, has emerged as a biomarker for diabetes risk. Although moderate alcohol consumption has been inversely associated with fetuin-A, data from clinical trials are lacking. Thus, we evaluated whether moderate alcohol consu

  13. Effect of moderate alcohol consumption on fetuin-A levels in men and women : post-hoc analyses of three open-label randomized crossover trials

    NARCIS (Netherlands)

    Joosten, Michel M.; Schrieks, Ilse C.; Hendriks, Henk F. J.

    2014-01-01

    Background: Fetuin-A, a liver-derived glycoprotein that impairs insulin-signalling, has emerged as a biomarker for diabetes risk. Although moderate alcohol consumption has been inversely associated with fetuin-A, data from clinical trials are lacking. Thus, we evaluated whether moderate alcohol cons

  14. Effect of moderate alcohol consumption on fetuin-A levels in men and women : post-hoc analyses of three open-label randomized crossover trials

    NARCIS (Netherlands)

    Joosten, Michel M.; Schrieks, Ilse C.; Hendriks, Henk F. J.

    2014-01-01

    Background: Fetuin-A, a liver-derived glycoprotein that impairs insulin-signalling, has emerged as a biomarker for diabetes risk. Although moderate alcohol consumption has been inversely associated with fetuin-A, data from clinical trials are lacking. Thus, we evaluated whether moderate alcohol cons

  15. Effect of moderate alcohol consumption on fetuin-A levels in men and women: Post-hoc analyses of three open-label randomized crossover trials

    NARCIS (Netherlands)

    Joosten, M.M.; Schrieks, I.C.; Hendriks, H.F.J.

    2014-01-01

    Background: Fetuin-A, a liver-derived glycoprotein that impairs insulin-signalling, has emerged as a biomarker for diabetes risk. Although moderate alcohol consumption has been inversely associated with fetuin-A, data from clinical trials are lacking. Thus, we evaluated whether moderate alcohol cons

  16. The Relationship of Circulating Fetuin-A With Liver Histology and Biomarkers of Systemic Inflammation in Nondiabetic Subjects with Nonalcoholic Fatty Liver Disease

    Science.gov (United States)

    Celebi, Gurkan; Genc, Halil; Gurel, Hasan; Sertoglu, Erdim; Kara, Muammer; Tapan, Serkan; Acikel, Cengizhan; Karslioglu, Yildirim; Ercin, Cemal Nuri; Dogru, Teoman

    2015-01-01

    Background/Aims: Fetuin-A, a glycoprotein with anti-inflammatory properties, plays an important role in counter-regulating inflammatory responses. It has also been associated with insulin resistance and metabolic syndrome. We aimed to investigate circulating concentrations of fetuin-A and its possible association with hepatic and systemic inflammation in nondiabetic subjects with nonalcoholic fatty liver disease (NAFLD). Patients and Methods: We included 105 nondiabetic male subjects with NAFLD [nonalcoholic steatohepatitis (NASH, n = 86) and simple steatosis (SS, n = 19)]. Plasma levels of fetuin-A and markers of inflammation [high-sensitive C reactive protein (hsCRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and adiponectin] were measured by enzyme-linked immunosorbent assay method. Insulin sensitivity was determined by homeostasis model assessment of insulin resistance (HOMA-IR) index. Results: Fetuin-A was negatively correlated with age (r = −0.27, P = 0.006), however there was no association between fetuin-A and body mass index, waist circumference (WC), glucose, insulin, HOMA-IR, lipid parameters, and inflammatory markers. In addition, no significant association was observed between fetuin-A and histological findings including liver fibrosis. Conclusion: This study demonstrated that plasma fetuin-A levels are not correlated with the hepatic histology and systemic markers of inflammation in nondiabetic subjects with NAFLD. Our data also suggested that age is significantly associated with fetuin-A in this clinically relevant condition. PMID:26021772

  17. Association of PPAR Alpha Intron 7 G/C, PPAR Gamma 2 Pro12Ala, and C161T Polymorphisms with Serum Fetuin-A Concentrations.

    Science.gov (United States)

    Márkus, Bernadett; Vörös, Krisztián; Supák, Dorina; Melczer, Zsolt; Cseh, Károly; Kalabay, László

    2017-01-01

    Both peroxisome activator proteins (PPARs) and fetuin-A play a role in lipid and glucose metabolism. We investigated whether PPARα intron 7 G2468/C and PPARγ2 Pro12Ala and PPARγ exon 6 C161T polymorphisms are associated with serum fetuin-A concentrations. The PPARα intron 7 G/C polymorphism was studied in cohort 1 (79 reference individuals, 165 postinfarction patients). The two PPARγ polymorphisms were investigated in cohort 2 (162 reference individuals, 165 postinfarction patients). Fetuin-A levels and PPAR polymorphisms were determined by radial immunodiffusion and polymerase chain reaction-restriction fragment length polymorphism techniques. The C allele variant of PPARα intron 7 G2467C was associated with higher fetuin-A levels (p = 0.018). Postinfarction status (p = 0.001), PPARα intron 7 GG/GC/CC genotypes (p = 0.032), and the C allele (p = 0.021) were the strongest determinants of fetuin-A concentration in a multiple regression model. Higher fetuin-A levels were associated with the Pro variant of PPARγ2 (p = 0.047). Postinfarction status (p = 0.041) and BMI (p < 0.001) but not PPARγ2 Pro were the strongest determinants of fetuin-A concentrations. PPARγ exon 6 C161T genotypes were not associated with fetuin-A levels. Fetuin-A was determined mainly by the PPARα intron 7C allele and postinfarction status in cohort 1 and the BMI and postinfarction in cohort 2. The PPARα intron 7C and PPARγ2 Pro variants are associated with fetuin-A levels.

  18. The effect of Helicobacter pylori eradication on macrophage migration inhibitory factor, C-reactive protein and fetuin-a levels

    Directory of Open Access Journals (Sweden)

    Levent Kebapcilar

    2010-06-01

    Full Text Available OBJECTIVES: To determine the effect of Helicobacter pylori (H. pylori eradication on blood levels of high-sensitivity C-reactive protein (hs-CRP, macrophage migration inhibitory factor and fetuin-A in patients with dyspepsia who are concurrently infected with H. pylori. METHODS: H.pylori infection was diagnosed based on the 14C urea breath test (UBT and histology. Lansoprazole 30 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily were given to all infected patients for 14 days; 14C UBT was then re-measured. In 30 subjects, migration inhibitory factor, fetuin-A and hs-CRP levels were examined before and after the eradication of H. pylori infection and compared to levels in 30 healthy subjects who tested negative for H. pylori infection. RESULTS: Age and sex distribution were comparable between patients and controls. Migration inhibitory factor and hs-CRP levels were higher, and fetuin-A levels were lower, in H. pylori-infected patients (p0.05. CONCLUSION: These findings suggest that H. pylori eradication reduces the levels of pro-inflammatory cytokines such as migration inhibitory factor and hs-CRP and also results in a significant increase in anti-inflammatory markers such as fetuin-A.

  19. Fetuin-A and albumin alter cytotoxic effects of calcium phosphate nanoparticles on human vascular smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Yana Dautova

    Full Text Available Calcification is a detrimental process in vascular ageing and in diseases such as atherosclerosis and arthritis. In particular, small calcium phosphate (CaP crystal deposits are associated with inflammation and atherosclerotic plaque de-stabilisation. We previously reported that CaP particles caused human vascular smooth muscle cell (VSMC death and that serum reduced the toxic effects of the particles. Here, we found that the serum proteins fetuin-A and albumin (≥ 1 µM reduced intracellular Ca2+ elevations and cell death in VSMCs in response to CaP particles. In addition, CaP particles functionalised with fetuin-A, but not albumin, were less toxic than naked CaP particles. Electron microscopic studies revealed that CaP particles were internalised in different ways; via macropinocytosis, membrane invagination or plasma membrane damage, which occurred within 10 minutes of exposure to particles. However, cell death did not occur until approximately 30 minutes, suggesting that plasma membrane repair and survival mechanisms were activated. In the presence of fetuin-A, CaP particle-induced damage was inhibited and CaP/plasma membrane interactions and particle uptake were delayed. Fetuin-A also reduced dissolution of CaP particles under acidic conditions, which may contribute to its cytoprotective effects after CaP particle exposure to VSMCs. These studies are particularly relevant to the calcification observed in blood vessels in patients with kidney disease, where circulating levels of fetuin-A and albumin are low, and in pathological situations where CaP crystal formation outweighs calcification-inhibitory mechanisms.

  20. Comparison of high-sensitivity C-reactive protein and fetuin-A levels before and after treatment for subjects with subclinical hyperthyroidism.

    Science.gov (United States)

    Bilgir, Oktay; Bilgir, Ferda; Topcuoglu, Tuba; Calan, Mehmet; Calan, Ozlem

    2014-03-01

    This study was designed to show the effect of propylthiouracil treatment on sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels on subjects with subclinical hyperthyroidism. After checking sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels of 35 patients with subclinical hyperthyroidism, each was given 50 mg tablets of propylthiouracil three times daily. After 3 months, sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels were then compared to the levels before treatment. Although high-sensitivity C-reactive protein and sCD40L levels were normal in the subclinical hyperthyroidism patients compared to the healthy controls, fetuin-A levels were statistically significantly higher (*p = 0.022). After treatment, fetuin-A levels of subclinical hyperthyroidism patients decreased statistically significantly compared to the levels before treatment (**p = 0.026). sCD40L and high-sensitivity C-reactive protein levels did not have a statistically significant difference compared to the control group and post-propylthiouracil treatment. In subclinical hyperthyroidism patients, high fetuin-A levels before propylthiouracil treatment and decreases in these levels after treatment in cases with subclinical hyperthyroidism indicated the possibility of preventing long-term cardiac complications with propylthiouracil treatment.

  1. Serum Fetuin-A Levels in Patients with Cardiovascular Disease: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Ze-Lin Sun

    2014-01-01

    Full Text Available Background. Fetuin-A (FA suppresses arterial calcification, promotes insulin resistance, and appears to be elevated in patients with cardiovascular diseases (CVD, but the data is still inconsistent. To clarify the correlation between serum FA levels and the presence and severity of CVDs, we performed this meta-analysis. Method. Potential relevant studies were identified covering the following databases: PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM, and China National Knowledge Infrastructure (CNKI databases. Data from eligible studies were extracted and included in the meta-analysis using a random-effects model. Results. Ten case-control studies, including 1,281 patients with CVDs and 2,663 healthy controls, were included. The results showed significant differences in serum levels of FA between the CVDs patients and the healthy controls (SMD = 1.36, 95%CI: 0.37–2.36, P=0.007. Ethnicity-subgroup analysis implied that low serum FA levels are related to CVDs in Caucasians (SMD = 1.73, 95%CI: 0.20–3.26, P=0.026, but not in Asians (SMD = 1.04, 95%CI: −0.33–2.40, P=0.138. Conclusion. The data indicated that decreased serum FA level is correlated with the development of CVDs. FA might be clinically valuable for reflecting the progression of CVDs.

  2. A rapid sandwich immunoassay for human fetuin A using agarose-3-aminopropyltriethoxysilane modified microtiter plate.

    Science.gov (United States)

    Vashist, Sandeep Kumar; Schneider, E Marion; Luong, John H T

    2015-07-09

    A rapid sandwich immunoassay (IA) with enhanced signal response for human fetuin A (HFA) was developed by modifying the surface of a KOH-treated polystyrene microtiter plate (MTP) with agarose and 3-aminopropyltriethoxysilane (APTES). The agarose-APTES complex binds covalently to the hydroxyl moiety of the MTP plate to serve as a binding platform for bioconjugation of EDC-activated anti-HFA antibody (Ab) via carbodiimide coupling. The one-step kinetics-based sandwich enzyme-linked immunosorbent assay (ELISA) enabled the detection of HFA in 30 min with a limit of detection (LOD) and a linear range of 0.02 ng mL(-1) and 1-243 ng mL(-1), respectively. It detected HFA spiked in diluted human whole blood and serum, and HFA in ethylenediaminetetraacetic acid (EDTA)-plasma of patients with high precision similar to that of conventional ELISA. The anti-HFA Ab-bound agarose-functionalized MTPs retained their functional activity after 6 weeks of storage in 0.1 M PBS, pH 7.4 at 4 °C.

  3. Allelic Imbalance of mRNA Associated with α2-HS Glycoprotein (Fetuin-A Polymorphism

    Directory of Open Access Journals (Sweden)

    Yoshihiko Inaoka

    2015-01-01

    Full Text Available Alpha 2-HS glycoprotein (AHSG, also designated as fetuin-A, exhibits polymorphism in population genetics consisting of two major alleles of AHSG∗1 and AHSG∗2. The serum level in the AHSG∗1 homozygote is significantly higher than that of the AHSG∗2 homozygote. This study examined the molecular mechanism for the cis-regulatory expression. To quantitate allele-specific mRNA in intra-assays of the heterozygote, RT-PCR method employing primers that were incorporated to the two closely located SNPs was developed. The respective magnitudes of AHSG∗1 to AHSG∗2 in the liver tissues and hepatic culture cells of PLC/PRF/5 were determined quantitatively as 2.5-fold and 6.2-fold. The mRNA expressional difference of two major alleles was observed, which is consistent with that in the serum level. The culture cells carried heterozygous genotypes in rs4917 and rs4918, but homozygous one in rs2248690. It was unlikely that the imbalance was derived from the SNP located in the promotor site. Furthermore, to investigate the effect of mRNA degradation, RNA synthesis in the cell culture was inhibited potently by the addition of actinomycin-D. No marked change was apparent between the two alleles. The results indicated that the cis-regulatory expressional difference is expected to occur at the level of transcription or splicing of mRNA.

  4. Allelic Imbalance of mRNA Associated with α2-HS Glycoprotein (Fetuin-A) Polymorphism.

    Science.gov (United States)

    Inaoka, Yoshihiko; Osawa, Motoki; Mukasa, Nahoko; Miyashita, Keiko; Satoh, Fumiko; Kakimoto, Yu

    2015-01-01

    Alpha 2-HS glycoprotein (AHSG), also designated as fetuin-A, exhibits polymorphism in population genetics consisting of two major alleles of AHSG(∗) 1 and AHSG(∗) 2. The serum level in the AHSG(∗) 1 homozygote is significantly higher than that of the AHSG(∗) 2 homozygote. This study examined the molecular mechanism for the cis-regulatory expression. To quantitate allele-specific mRNA in intra-assays of the heterozygote, RT-PCR method employing primers that were incorporated to the two closely located SNPs was developed. The respective magnitudes of AHSG(∗) 1 to AHSG(∗) 2 in the liver tissues and hepatic culture cells of PLC/PRF/5 were determined quantitatively as 2.5-fold and 6.2-fold. The mRNA expressional difference of two major alleles was observed, which is consistent with that in the serum level. The culture cells carried heterozygous genotypes in rs4917 and rs4918, but homozygous one in rs2248690. It was unlikely that the imbalance was derived from the SNP located in the promotor site. Furthermore, to investigate the effect of mRNA degradation, RNA synthesis in the cell culture was inhibited potently by the addition of actinomycin-D. No marked change was apparent between the two alleles. The results indicated that the cis-regulatory expressional difference is expected to occur at the level of transcription or splicing of mRNA.

  5. Increased adipose tissue secretion of Fetuin-A, lipopolysaccharide-binding protein and high-mobility group box protein 1 in metabolic syndrome.

    Science.gov (United States)

    Jialal, Ishwarlal; Devaraj, Sridevi; Bettaieb, Ahmed; Haj, Fawaz; Adams-Huet, Beverley

    2015-07-01

    Adipose Tissue (AT) dysregulation contributes to the pro-inflammatory state and insulin resistance of Metabolic Syndrome (MetS). We examined AT secretion of the hepatokine, Fetuin-A, LBP, sCD14 and HMGB-1, and toll-like receptor 2 and 4 protein levels in MetS and controls. Secreted levels of Fetuin-A, LBP, HMGB-1 and sCD14 and TLR2 and TLR4 protein in AT of controls and MetS patients were assayed. Also mRNA and protein for Fetuin-A, LBP, sCD14 and HMGB-1 were studied in subcutaneous fat depot of mice and during adipocyte differentiation. Secretion of Fetuin-A, LBP and HMGB-1 from AT were significantly increased in MetS (n = 28) compared to controls (n = 25), even after adjustment for adiposity. There were no significant differences in sCD14. Both LBP and Fetuin-A correlated significantly with HOMA-IR and increased significantly with increasing features of MetS. There was a significant increase in AT TLR2 and TLR4 protein in MetS compared to controls. Expression of Fetuin-A and LBP were significantly higher in subcutaneous white adipose tissue of HFD fed mice as well as in ob/ob mice compared to C57BL6/J control mice (n = 6 per group). Additionally mRNA and protein levels of FetA, LBP and HMGB-1 increased during differentiation of 3T3-L1 adipocytes. We make the novel observation of increased secretion of Fetuin A, LBP and HMGB-1 from AT and hypothesize that these engage TLRs in AT and other tissues contributing to the pro-inflammatory state and insulin resistance of MetS. Published by Elsevier Ireland Ltd.

  6. Comparison of Chemiluminescence vs. Infrared Techniques for Detection of Fetuin-A in Saliva.

    Science.gov (United States)

    Mathews, Suresh T; Graff, Emily; Judd, Robert L; Kothari, Vishal

    2015-01-01

    The western blotting technique for transfer and detection of proteins, named following the discovery of southern and northern blotting for DNA- and RNA-blotting, respectively, has traditionally relied on the use of X-ray films to capture chemiluminescence. Recent advancements use super-cooled charge coupled devices (CCD) cameras to capture both chemiluminescence and fluorescence images, which exhibit a greater dynamic range compared to traditional X-ray film. Chemiluminescence detected by a CCD camera records photons and displays an image based on the amount of light generated as a result of a dynamic chemical reaction. Fluorescent detection with a CCD camera, on the other hand, is measured in a static state. Despite this advantage, researchers continue to widely use chemiluminescent detection methods due to the generally poor performance of fluorophores in the visible spectrum. Infrared imaging systems offer a solution to the dynamic reactions of chemiluminescence and the poor performance of fluorophores detected in the visible spectrum, by imaging fluorophores in the infrared spectrum. Infrared imaging is static, has a wide linear range, high sensitivity, and reduced autofluorescence and light scatter. A distinct advantage of infrared imaging is the ability to detect two target proteins simultaneously on the same blot which increases accuracy of quantification and comparison, while minimizing the need for stripping and reprobing. Here, we compare the methodology for chemiluminescent (UVP BioChemi) and infrared (UVP Odyssey) detection of salivary total and phosphorylated fetuin-A, a multifunctional protein associated with cardio-metabolic risk, and discuss the advantages and disadvantages of these methodologies.

  7. Higher fetuin-A, lower adiponectin and free leptin levels mediate effects of excess body weight on insulin resistance and risk for myelodysplastic syndrome.

    Science.gov (United States)

    Dalamaga, Maria; Karmaniolas, Konstantinos; Chamberland, John; Nikolaidou, Athina; Lekka, Antigoni; Dionyssiou-Asteriou, Amalia; Mantzoros, Christos S

    2013-12-01

    Excess body weight has been implicated in the pathogenesis of myelodysplastic syndrome (MDS). We thus explored the role of serum fetuin-A reflecting ectopic hepatic fat deposition when storage capacity of adipocytes has been exceeded, free leptin reflecting overall fat mass and adiponectin reflecting visceral fat mass, all potential mediators of the effects of obesity on insulin resistance and, consequently, to MDS risk. In a hospital-based case-control study, we studied 101 cases with incident, histologically confirmed primary MDS and 101 controls matched on gender, age and date of diagnosis, between 2004 and 2007. Serum fetuin-A, adiponectin, leptin, leptin receptor, free leptin and insulin were determined. Higher serum fetuin-A, lower adiponectin and lower free leptin were all individually and independently associated with higher risk of MDS before and after controlling for matching and risk factors, such as age, gender, date of diagnosis, body mass index (BMI), family history of lymphohematopoietic cancer, smoking history and serum insulin. Interestingly, we have shown that these associations were prominent among overweight/obese individuals and persisted after controlling for BMI and serum insulin indicating that their effects are above and beyond insulinemia only. Elevated serum fetuin-A but lower adiponectin and free leptin are associated with higher risk of MDS particularly among overweight/obese individuals. These findings suggest that the association between excessive weight gain and the risk of MDS could be mediated by fetuin-A, adiponectin and free leptin, which may have potential clinical and preventive implications. © 2013.

  8. The Relationship of Fetuin-A, Adiponectin, Retinol Binding Protein-4 (RBP-4 and High Sensitivity C-Reactive Protein (hsCRP with Insulin Resistance (HOMA-IR in Obese Non Diabetic Men

    Directory of Open Access Journals (Sweden)

    Imelda Novianti

    2012-04-01

    Full Text Available BACKGROUND: Central obesity is the accumulation of visceral (intra-abdominal fat and is strongly known to be associated with insulin resistance and type 2 diabetes mellitus (T2DM. Obesity can cause adipocyte hypertrophy that results in dysregulation of adipokine expression. The abnormal function of adipocytes may play an important role in the development of a chronic low-grade proinflammatory state associated with obesity. Adiponectin, retinol binding protein (RBP-4 and fetuin-A play a role in the pathophysiology of insulin resistance. Expression of fetuin-A is increased due to fat accumulation in the liver. Elevated concentration of fetuin-A in the circulation can impair insulin signaling in muscle and liver as well as suppress adiponectin secretion, although its molecular mechanism is still unclear. The aim of this study was to identify the relationship of fetuin-A, adiponectin, RBP-4 and hsCRP with insulin resistance in obese non diabetic men. METHODS: This was an observational study with a cross-sectional design. The study subjects were 64 men with non diabetic abdominal obesity, characterized by waist circumference of 98.47±5.88 cm and fasting blood glucose of 85.75±8.36 mg/dL. RESULTS: This study showed that fetuin-A was positively correlated with HOMA-IR in obese non diabetic men with insulin resistance (r=0.128; p=0.570, although not significant. Fetuin-A was found to be correlated with adiponectin, RBP-4 and hsCRP (r=0.150; p=0.233; r=0.050; p=0.711; r=-0.04; p=0.445, although not significant. CONCLUSIONS: The concentration of fetuin-A showed a tendency to be positively correlated with HOMA-IR and with RBP-4 in obese non diabetic men, although statistically not significant. The concentration of fetuin-A showed a tendency to be negatively correlated with adiponectin and hsCRP although statistically not significant. There was no interrelationship between fetuin-A, adiponectin, RBP-4, hsCRP and HOMA-IR. Elevated concentrations of fetuin-A

  9. Serum vitamin D, intact parathyroid hormone, and Fetuin A concentrations were associated with geriatric sarcopenia and cardiac hypertrophy

    Science.gov (United States)

    Chang, Wei-Ting; Wu, Chih-Hsing; Hsu, Ling-Wei; Chen, Po-Wei; Yu, Jia-Rong; Chang, Chin-Sung; Tsai, Wei-Chuan; Liu, Ping-Yen

    2017-01-01

    With aging, intact parathyroid hormone (iPTH) increases. It plays a crucial role in left ventricular hypertrophy (LVH). Also, 25-hydroxy vitamin D (Vit-D) and iPTH have been observed to be determinants of muscle wasting known as sarcopenia. Fetuin A (FetA), a systemic calcification inhibitor, involves in the development of diastolic heart failure. Hence, we hypothesized that the interplay among FetA, Vit-D and iPTH may contribute to sarcopenic LVH among the elders. We analyzed a database from the Tianliao Old People study with 541 elders (≥65 years) in a Taiwan’s suburban community. After excluding patients with renal function impairment, 120/449 (26.7%) patients were diagnosed with sarcopenia. Sarcopenic patients had lower serum Vit-D levels but higher FetA as well as iPTH. Notably, sarcopenic patients with LVH had significantly lower FetA and higher iPTH levels. In multivariate logistic regression analysis, only the increase in iPTH was independently associated with sarcopenic LVH (Odds ratio: 1.05; confidence interval: 1.03–1.08, p = 0.005). Using iPTH >52.3 ng/l as a cutoff point, the sensitivity and specificity was 66% and 84%, respectively. In conclusion, FetA, Vit-D, and iPTH levels were all associated with sarcopenia in this geriatric population. Among them, iPTH specifically indicates patients with sarcopenic LVH. PMID:28112206

  10. Serum Interleukin-18, Fetuin-A, Soluble Intercellular Adhesion Molecule-1, and Endothelin-1 in Ankylosing Spondylitis, Psoriatic Arthritis, and SAPHO Syndrome.

    Science.gov (United States)

    Przepiera-Będzak, Hanna; Fischer, Katarzyna; Brzosko, Marek

    2016-08-03

    To examine serum interleukin 18 (IL-18), fetuin-A, soluble intercellular adhesion molecule-1 (sICAM-1), and endothelin-1 (ET-1) levels in ankylosing spondylitis (AS), psoriatic arthritis (PsA), and Synovitis Acne Pustulosis Hyperostosis Osteitis syndrome (SAPHO). We studied 81 AS, 76 PsA, and 34 SAPHO patients. We measured serum IL-18, fetuin-A, sICAM-1, ET-1, IL-6, IL-23, vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). IL-18 levels were higher in AS (p = 0.001), PsA (p = 0.0003), and SAPHO (p = 0.01) than in controls, and were positively correlated with CRP (p = 0.03), VEGF (p = 0.03), and total cholesterol (TC, p = 0.006) in AS and with IL-6 (p = 0.03) in PsA. Serum fetuin-A levels were lower in AS (p = 0.001) and PsA (p = 0.001) than in controls, and negatively correlated with C-reactive protein (CRP) in AS (p = 0.04) and SAPHO (p = 0.03). sICAM-1 positively correlated with CRP (p = 0.01), erythrocyte sedimentation rate (ESR, p = 0.01), and IL-6 (p = 0.008) in AS, and with IL-6 (p = 0.001) in SAPHO. Serum ET-1 levels were lower in AS (p = 0.0005) than in controls. ET-1 positively correlated with ESR (p = 0.04) and Disease Activity Score 28 (DAS28, p = 0.003) in PsA. In spondyloarthritis, markers of endothelial function correlated with disease activity and TC.

  11. Serum Interleukin-18, Fetuin-A, Soluble Intercellular Adhesion Molecule-1, and Endothelin-1 in Ankylosing Spondylitis, Psoriatic Arthritis, and SAPHO Syndrome

    Directory of Open Access Journals (Sweden)

    Hanna Przepiera-Będzak

    2016-08-01

    Full Text Available To examine serum interleukin 18 (IL-18, fetuin-A, soluble intercellular adhesion molecule-1 (sICAM-1, and endothelin-1 (ET-1 levels in ankylosing spondylitis (AS, psoriatic arthritis (PsA, and Synovitis Acne Pustulosis Hyperostosis Osteitis syndrome (SAPHO. We studied 81 AS, 76 PsA, and 34 SAPHO patients. We measured serum IL-18, fetuin-A, sICAM-1, ET-1, IL-6, IL-23, vascular endothelial growth factor (VEGF, and epidermal growth factor (EGF. IL-18 levels were higher in AS (p = 0.001, PsA (p = 0.0003, and SAPHO (p = 0.01 than in controls, and were positively correlated with CRP (p = 0.03, VEGF (p = 0.03, and total cholesterol (TC, p = 0.006 in AS and with IL-6 (p = 0.03 in PsA. Serum fetuin-A levels were lower in AS (p = 0.001 and PsA (p = 0.001 than in controls, and negatively correlated with C-reactive protein (CRP in AS (p = 0.04 and SAPHO (p = 0.03. sICAM-1 positively correlated with CRP (p = 0.01, erythrocyte sedimentation rate (ESR, p = 0.01, and IL-6 (p = 0.008 in AS, and with IL-6 (p = 0.001 in SAPHO. Serum ET-1 levels were lower in AS (p = 0.0005 than in controls. ET-1 positively correlated with ESR (p = 0.04 and Disease Activity Score 28 (DAS28, p = 0.003 in PsA. In spondyloarthritis, markers of endothelial function correlated with disease activity and TC.

  12. Visceral and subcutaneous adipose tissue express and secrete functional alpha2hsglycoprotein (fetuin a) especially in obesity.

    Science.gov (United States)

    Pérez-Sotelo, Diego; Roca-Rivada, Arturo; Larrosa-García, María; Castelao, Cecilia; Baamonde, Iván; Baltar, Javier; Crujeiras, Ana Belen; Seoane, Luisa María; Casanueva, Felipe F; Pardo, María

    2017-02-01

    The secretion of the hepatokine alpha-2-Heremans-Schmid glycoprotein/Fetuin A, implicated in pathological processes including systemic insulin resistance, by adipose tissue has been recently described. Thus, we have recently identified its presence in white adipose tissue secretomes by mass spectrometry. However, the secretion pattern and function of adipose-derived alpha-2-Heremans-Schmid glycoprotein are poorly understood. The aim of this study is to evaluate the expression and secretion of total and active phosphorylated alpha-2-Heremans-Schmid glycoprotein by adipose tissue from visceral and subcutaneous localizations in animals at different physiological and nutritional status including anorexia and obesity. Alpha-2-Heremans-Schmid glycoprotein expression and secretion in visceral adipose tissue and subcutaneous adipose tissue explants from animals under fasting and exercise training, at pathological situations such as anorexia and obesity, and from human obese individuals were assayed by immunoblotting, quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. We reveal that visceral adipose tissue expresses and secretes more alpha-2-Heremans-Schmid glycoprotein than subcutaneous adipose tissue, and that this secretion is diminished after fasting and exercise training. Visceral adipose tissue from anorectic animals showed reduced alpha-2-Heremans-Schmid glycoprotein secretion; on the contrary, alpha-2-Heremans-Schmid glycoprotein is over-secreted by visceral adipose tissue in the occurrence of obesity. While secretion of active-PhophoSer321α2HSG by visceral adipose tissue is independent of body mass index, we found that the fraction of active-alpha-2-Heremans-Schmid glycoprotein secreted by subcutaneous adipose tissue increments significantly in situations of obesity. Functional studies show that the inhibition of adipose-derived alpha-2-Heremans-Schmid glycoprotein increases insulin sensitivity in differentiated adipocytes. In

  13. Early malnutrition attenuates the impairing action of naloxone on spreading depression in young rats.

    Science.gov (United States)

    Guedes, Rubem Carlos Araújo; Rocha-de-Melo, Ana Paula; de Lima, Kalina Rimena; de Albuquerque, Juliana da Mota Silveira; Francisco, Elian da Silva

    2013-07-01

    Malnutrition early in life can disrupt neurotransmitter systems in the brain, affecting its electrophysiological function. The opioid receptor antagonist naloxone can affect the electroencephalogram (EEG) and behavior in animals and humans, and patients under drug-abuse treatment use it as a therapy. The goal of this work in the rat is to determine whether malnutrition early in life modulates the action of naloxone on the excitability-related phenomenon known as cortical spreading depression (CSD). Malnutrition was induced by feeding the dams during the gestation and lactation with a low-protein diet (8% protein). Their male pups received a single daily subcutaneous injection of naloxone (10 mg/kg/day) from the 7th to the 28th postnatal day, and were subsequently (30-40 days of life) submitted to a 4-hours CSD recording session, with electrodes at two points at a fixed distance apart on the parietal cortical surface. Compared to well-nourished rats receiving a 23% protein diet, malnourished animals displayed lower body weights and higher CSD velocities of propagation, confirming the facilitating effect of malnutrition on CSD. Naloxone treatment reduced in well-nourished rats the CSD propagation velocity, as compared to saline-injected controls. In contrast, the naloxone effect was less intense in the malnourished condition, and the CSD velocity difference between malnourished-naloxone and malnourished-saline groups did not reach statistical significance. Data strongly support the involvement of opioid-based mechanisms in excitability-related neural processes, which probably influence CSD propagation, and indicate that early malnutrition attenuates the impairing action of naloxone on CSD.

  14. Quantitative attenuation analysis for identification of early Barrett's neoplasia in volumetric laser endomicroscopy.

    Science.gov (United States)

    Swager, Anne-Fre; Faber, Dirk J; de Bruin, Daniel M; Weusten, Bas L; Meijer, Sybren L; Bergman, Jacques J; Curvers, Wouter L; van Leeuwen, Ton G

    2017-08-01

    Early neoplasia in Barrett’s esophagus (BE) is difficult to detect. Volumetric laser endomicroscopy (VLE) incorporates optical coherence tomography, providing a circumferential scan of the esophageal wall layers. The attenuation coefficient (μVLE) quantifies decay of detected backscattered light versus depth, and could potentially improve BE neoplasia detection. The aim is to investigate feasibility of μVLE for identification of early BE neoplasia. In vivo and ex vivo VLE scans with histological correlation from BE patients ± neoplasia were used. Quantification by μVLE was performed manually on areas of interest (AoIs) to differentiate neoplasia from nondysplastic (ND)BE. From ex vivo VLE scans from 16 patients (13 with neoplasia), 68 AoIs were analyzed. Median μVLE values (mm−1) were 3.7 [2.1 to 4.4 interquartile range (IQR)] for NDBE and 4.0 (2.5 to 4.9 IQR) for neoplasia, not statistically different (p=0.82). Fourteen in vivo scans were used: nine from neoplastic and five from NDBE patients. Median μVLE values were 1.8 (1.5 to 2.6 IQR) for NDBE and 2.1 (1.9 to 2.6 IQR) for neoplasia, with no statistically significant difference (p=0.37). In conclusion, there was no significant difference in μVLE values in VLE scans from early neoplasia versus NDBE. Future studies with a larger sample size should explore other quantitative methods for detection of neoplasia during BE surveillance.

  15. Effects of citicoline on level of consciousness, serum level of fetuin-A and matrix Gla-protein (MGP) in trauma patients with diffuse axonal injury (DAI) and GCS≤8.

    Science.gov (United States)

    Shokouhi, Ghaffar; Haghjoo, Amir Ghorbani; Sattarnezhad, Neda; Asghari, Mohammad; Sattarnezhad, Aida; Asghari, Ali; Pezeshki, Arastoo

    2014-11-01

    Citicoline, a neuroprotective drug, has been suggested to improve level of consciousness, mitigating secondary to brain damage and ectopic vascular calcification, following post-traumatic neurogenesis and angiogenesis, inducing calcification modulators, like fetuin-A and matrix Gla-protein (MGP). This study aimed to investigate effects of citicoline on levels of consciousness, serum levels of fetuin-A and MGP in patients with severe traumatic brain injury. This double blind randomized controlled trial (RCT) was conducted on patients with diagnosis of diffuse axonal injury (DAI) and GCS≤8. The cases were treated with citicoline (500 mg every 6 hours) intravenously for fifteen days. Daily GCS assessment and intermittent blood sampling were done for both cases and controls. Fifty-eight patients were included in the study and during the study period, mean GCS levels improved in both groups; however, the difference was inconsiderable (p>0.05). Serum levels of fetuin-A, a negative phase reactant, increased in the group treated with citicoline (p=0.012), while these changes were insignificant for the controls (p=0.455). Serum levels of MGP, a calcification inhibitor, increased in the cases (p=0.046). The alterations were inconsequential in the control group (p=0.405). The findings of this study suggest neutral effects of citicoline on level of consciousness and GCS. Through increasing levels of fetuin-A and MGP, citicoline may have protective effects against inflammatory damage and vascular calcification secondary to head trauma.

  16. Early transient mild hypothermia attenuates neurological deficits and brain damage after experimental subarachnoid hemorrhage in rats.

    Science.gov (United States)

    Lilla, Nadine; Rinne, Christoph; Weiland, Judith; Linsenmann, Thomas; Ernestus, Ralf-Ingo; Westermaier, Thomas

    2017-09-23

    Metabolic exhaustion in ischemic tissue is the basis for a detrimental cascade of cell damage. In the acute stage of subarachnoid hemorrhage (SAH), a sequence of global and focal ischemia occurs, threatening brain tissue to undergo ischemic damage. This study was conducted to investigate whether early therapy with moderate hypothermia can offer neuroprotection after experimental SAH. 20 male Sprague-Dawley rats were subjected to SAH and treated by active cooling (34° C) or served as controls by continuous maintenance of normothermia (37.0° C). Mean arterial blood pressure (MABP), intracranial pressure (ICP) and local cerebral blood flow (CBF) over both hemispheres were continuously measured. Neurological assessment was performed 24 hours later. Hippocampal damage was assessed by hematoxylin and eosin and Caspase-3 staining. By a slight increase of MABP in the cooling phase and a significant reduction of ICP, hypothermia improved cerebral perfusion pressure (CPP) in the first 60 minutes after SAH. Accordingly, a trend to increased CBF was observed during this period. The rate of injured neurons was significantly reduced in hypothermia-treated animals compared to normothermic controls. The results of this series cannot finally answer whether this form of treatment permanently attenuates or only delays ischemic damage. In the latter case, slowing down metabolic exhaustion by hypothermia may still be a valuable treatment during this state of ischemic brain damage and prolong the therapeutic window for possible causal treatments of the acute perfusion deficit. Therefore, it may be useful as a first-tier therapy in suspected SAH. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Early biodistribution and persistence of a protective live attenuated SIV vaccine elicits localised innate responses in multiple lymphoid tissues.

    Directory of Open Access Journals (Sweden)

    Deborah Ferguson

    Full Text Available Vaccination of Mauritian cynomolgus macaques with the attenuated nef-truncated C8 variant of SIVmac251/32H (SIVmacC8 induces early, potent protection against pathogenic, heterologous challenge before the maturation of cognate immunity. To identify processes that contribute to early protection in this model the pathogenesis, anatomical distribution and viral vaccine kinetics were determined in relation to localised innate responses triggered by vaccination. The early biodistribution of SIVmacC8 was defined by rapid, widespread dissemination amongst multiple lymphoid tissues, detectable after 3 days. Cell-associated viral RNA dynamics identified mesenteric lymph nodes (MLN and spleen, as well as the gut mucosae, as early major contributors of systemic virus burden. Rapid, localised infection was populated by discrete foci of persisting virus-infected cells. Localised productive infection triggered a broad innate response, with type-1 interferon sensitive IRF-7, STAT-1, TRIM5α and ApoBEC3G genes all upregulated during the acute phase but induction did not prevent viral persistence. Profound changes in vaccine-induced cell-surface markers of immune activation were detected on macrophages, B-cells and dendritic cells (DC-SIGN, S-100, CD40, CD11c, CD123 and CD86. Notably, high DC-SIGN and S100 staining for follicular and interdigitating DCs respectively, in MLN and spleen were detected by 3 days, persisting 20 weeks post-vaccination. Although not formally evaluated, the early biodistribution of SIVmacC8 simultaneously targets multiple lymphoid tissues to induce strong innate immune responses coincident at the same sites critical for early protection from wild-type viruses. HIV vaccines which stimulate appropriate innate, as well as adaptive responses, akin to those generated by live attenuated SIV vaccines, may prove the most efficacious.

  18. Hypothermia induced by adenosine 5'-monophosphate attenuates early stage injury in an acute gouty arthritis rat model.

    Science.gov (United States)

    Miao, Zhimin; Guo, Weiting; Lu, Shulai; Lv, Wenshan; Li, Changgui; Wang, Yangang; Zhao, Shihua; Yan, Shengli; Tao, Zhenyin; Wang, Yunlong

    2013-08-01

    To investigate whether the hypothermia induced by Adenosine 5'-Monophosphate (5'-AMP) could attenuate early stage injury in a rat acute gouty arthritis model. Ankle joint injection with monosodium urate monohydrate crystals (MSU crystals) in hypothermia rat model which was induced by 5'-AMP and then observe whether hypothermia induced by 5'-AMP could be effectively inhibit the inflammation on acute gouty arthritis in rats. AMP-induced hypothermia has protective effects on our acute gouty arthritis, which was demonstrated by the following criteria: (1) a significant reduction in the ankle swelling (p gouty arthritis model.

  19. Early potent protection against heterologous SIVsmE660 challenge following live attenuated SIV vaccination in Mauritian cynomolgus macaques.

    Directory of Open Access Journals (Sweden)

    Neil Berry

    Full Text Available BACKGROUND: Live attenuated simian immunodeficiency virus (SIV vaccines represent the most effective means of vaccinating macaques against pathogenic SIV challenge. However, thus far, protection has been demonstrated to be more effective against homologous than heterologous strains. Immune correlates of vaccine-induced protection have also been difficult to identify, particularly those measurable in the peripheral circulation. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe potent protection in 6 out of 8 Mauritian-derived cynomolgus macaques (MCM against heterologous virus challenge with the pathogenic, uncloned SIVsmE660 viral stock following vaccination with live attenuated SIVmac251/C8. MCM provided a characterised host genetic background with limited Major Histocompatibility Complex (MHC and TRIM5α allelic diversity. Early protection, observed as soon as 3 weeks post-vaccination, was comparable to that of 20 weeks vaccination. Recrudescence of vaccine virus was most pronounced in breakthrough cases where simultaneous identification of vaccine and challenge viruses by virus-specific PCR was indicative of active co-infection. Persistence of the vaccine virus in a range of lymphoid tissues was typified by a consistent level of SIV RNA positive cells in protected vaccinates. However, no association between MHC class I/II haplotype or TRIM5α polymorphism and study outcome was identified. CONCLUSION/SIGNIFICANCE: This SIV vaccine study, conducted in MHC-characterised MCM, demonstrated potent protection against the pathogenic, heterologous SIVsmE660 challenge stock after only 3 weeks vaccination. This level of protection against this viral stock by intravenous challenge has not been hitherto observed. The mechanism(s of protection by vaccination with live attenuated SIV must account for the heterologous and early protection data described in this study, including those which relate to the innate immune system.

  20. Melatonin attenuated early brain injury induced by subarachnoid hemorrhage via regulating NLRP3 inflammasome and apoptosis signaling.

    Science.gov (United States)

    Dong, Yushu; Fan, Chongxi; Hu, Wei; Jiang, Shuai; Ma, Zhiqiang; Yan, Xiaolong; Deng, Chao; Di, Shouyin; Xin, Zhenlong; Wu, Guiling; Yang, Yang; Reiter, Russel J; Liang, Guobiao

    2016-04-01

    Subarachnoid hemorrhage (SAH) is a devastating condition with high morbidity and mortality rates due to the lack of effective therapy. Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation associated with the upregulation of apoptotic signaling pathway has been implicated in various inflammatory diseases including hemorrhagic insults. Melatonin is reported to possess substantial anti-inflammatory properties, which is beneficial for early brain injury (EBI) after SAH. However, the molecular mechanisms have not been clearly identified. This study was designed to investigate the protective effects of melatonin against EBI induced by SAH and to elucidate the potential mechanisms. The adult mice were subjected to SAH. Melatonin or vehicle was injected intraperitoneally 2 hr after SAH. Melatonin was neuroprotective, as shown by increased survival rate, as well as elevated neurological score, greater survival of neurons, preserved brain glutathione levels, and reduced brain edema, malondialdehyde concentrations, apoptotic ratio, and blood-brain barrier (BBB) disruption. Melatonin also attenuated the expressions of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved caspase-1, interleukin-1β (IL-1β), and interleukin-6 (IL-6); these changes were also associated with an increase in the anti-apoptotic factor (Bcl2) and reduction in the pro-apoptotic factor (Bim). In summary, our results demonstrate that melatonin treatment attenuates the EBI following SAH by inhibiting NLRP3 inflammasome-associated apoptosis.

  1. Levetiracetam attenuates hippocampal expression of synaptic plasticity-related immediate early and late response genes in amygdala-kindled rats

    Science.gov (United States)

    2010-01-01

    Background The amygdala-kindled rat is a model for human temporal lobe epilepsy and activity-dependent synaptic plasticity. Hippocampal RNA isolated from amygdala-kindled rats at different kindling stages was analyzed to identify kindling-induced genes. Furthermore, effects of the anti-epileptic drug levetiracetam on kindling-induced gene expression were examined. Results Cyclooxygenase-2 (Cox-2), Protocadherin-8 (Pcdh8) and TGF-beta-inducible early response gene-1 (TIEG1) were identified and verified as differentially expressed transcripts in the hippocampus of kindled rats by in situ hybridization and quantitative RT-PCR. In addition, we identified a panel of 16 additional transcripts which included Arc, Egr3/Pilot, Homer1a, Ania-3, MMP9, Narp, c-fos, NGF, BDNF, NT-3, Synaptopodin, Pim1 kinase, TNF-α, RGS2, Egr2/krox-20 and β-A activin that were differentially expressed in the hippocampus of amygdala-kindled rats. The list consists of many synaptic plasticity-related immediate early genes (IEGs) as well as some late response genes encoding transcription factors, neurotrophic factors and proteins that are known to regulate synaptic remodelling. In the hippocampus, induction of IEG expression was dependent on the afterdischarge (AD) duration. Levetiracetam, 40 mg/kg, suppressed the development of kindling measured as severity of seizures and AD duration. In addition, single animal profiling also showed that levetiracetam attenuated the observed kindling-induced IEG expression; an effect that paralleled the anti-epileptic effect of the drug on AD duration. Conclusions The present study provides mRNA expression data that suggest that levetiracetam attenuates expression of genes known to regulate synaptic remodelling. In the kindled rat, levetiracetam does so by shortening the AD duration thereby reducing the seizure-induced changes in mRNA expression in the hippocampus. PMID:20105316

  2. Levetiracetam attenuates hippocampal expression of synaptic plasticity-related immediate early and late response genes in amygdala-kindled rats

    Directory of Open Access Journals (Sweden)

    Watson William P

    2010-01-01

    Full Text Available Abstract Background The amygdala-kindled rat is a model for human temporal lobe epilepsy and activity-dependent synaptic plasticity. Hippocampal RNA isolated from amygdala-kindled rats at different kindling stages was analyzed to identify kindling-induced genes. Furthermore, effects of the anti-epileptic drug levetiracetam on kindling-induced gene expression were examined. Results Cyclooxygenase-2 (Cox-2, Protocadherin-8 (Pcdh8 and TGF-beta-inducible early response gene-1 (TIEG1 were identified and verified as differentially expressed transcripts in the hippocampus of kindled rats by in situ hybridization and quantitative RT-PCR. In addition, we identified a panel of 16 additional transcripts which included Arc, Egr3/Pilot, Homer1a, Ania-3, MMP9, Narp, c-fos, NGF, BDNF, NT-3, Synaptopodin, Pim1 kinase, TNF-α, RGS2, Egr2/krox-20 and β-A activin that were differentially expressed in the hippocampus of amygdala-kindled rats. The list consists of many synaptic plasticity-related immediate early genes (IEGs as well as some late response genes encoding transcription factors, neurotrophic factors and proteins that are known to regulate synaptic remodelling. In the hippocampus, induction of IEG expression was dependent on the afterdischarge (AD duration. Levetiracetam, 40 mg/kg, suppressed the development of kindling measured as severity of seizures and AD duration. In addition, single animal profiling also showed that levetiracetam attenuated the observed kindling-induced IEG expression; an effect that paralleled the anti-epileptic effect of the drug on AD duration. Conclusions The present study provides mRNA expression data that suggest that levetiracetam attenuates expression of genes known to regulate synaptic remodelling. In the kindled rat, levetiracetam does so by shortening the AD duration thereby reducing the seizure-induced changes in mRNA expression in the hippocampus.

  3. Ceruloplasmin gene-deficient mice with experimental autoimmune encephalomyelitis show attenuated early disease evolution.

    Science.gov (United States)

    Gresle, Melissa M; Schulz, Katrin; Jonas, Anna; Perreau, Victoria M; Cipriani, Tania; Baxter, Alan G; Miranda-Hernandez, Socorro; Field, Judith; Jokubaitis, Vilija G; Cherny, Robert; Volitakis, Irene; David, Samuel; Kilpatrick, Trevor J; Butzkueven, Helmut

    2014-06-01

    We conducted a microarray study to identify genes that are differentially regulated in the spinal cords of mice with the inflammatory disease experimental autoimmune encephalomyelitis (EAE) relative to healthy mice. In total 181 genes with at least a two-fold increase in expression were identified, and most of these genes were associated with immune function. Unexpectedly, ceruloplasmin (Cp), a ferroxidase that converts toxic ferrous iron to its nontoxic ferric form and also promotes the efflux of iron from astrocytes in the CNS, was shown to be highly upregulated (13.2-fold increase) in EAE spinal cord. Expression of Cp protein is known to be increased in several neurological conditions, but the role of Cp regulation in CNS autoimmune disease is not known. To investigate this, we induced EAE in Cp gene knockout, heterozygous, and wild-type mice. Cp knockout mice were found to have slower disease evolution than wild-type mice (EAE days 13-17; P = 0.05). Interestingly, Cp knockout mice also exhibited a significant increase in the number of astrocytes with reactive morphology in early EAE compared with wild-type mice at the same stage of disease. CNS iron levels were not increased with EAE in these mice. Based on these observations, we propose that an increase in Cp expression could contribute to tissue damage in early EAE. In addition, endogenous CP either directly or indirectly inhibits astrocyte reactivity during early disease, which could also worsen early disease evolution.

  4. Anesthesia-Induced Hypothermia Attenuates Early-Phase Blood-Brain Barrier Disruption but Not Infarct Volume following Cerebral Ischemia.

    Science.gov (United States)

    Liu, Yu-Cheng; Lee, Yu-Da; Wang, Hwai-Lee; Liao, Kate Hsiurong; Chen, Kuen-Bao; Poon, Kin-Shing; Pan, Yu-Ling; Lai, Ted Weita

    2017-01-01

    Blood-brain barrier (BBB) disruption is thought to facilitate the development of cerebral infarction after a stroke. In a typical stroke model (such as the one used in this study), the early phase of BBB disruption reaches a peak 6 h post-ischemia and largely recovers after 8-24 h, whereas the late phase of BBB disruption begins 48-58 h post-ischemia. Because cerebral infarct develops within 24 h after the onset of ischemia, and several therapeutic agents have been shown to reduce the infarct volume when administered at 6 h post-ischemia, we hypothesized that attenuating BBB disruption at its peak (6 h post-ischemia) can also decrease the infarct volume measured at 24 h. We used a mouse stroke model obtained by combining 120 min of distal middle cerebral arterial occlusion (dMCAo) with ipsilateral common carotid arterial occlusion (CCAo). This model produced the most reliable BBB disruption and cerebral infarction compared to other models characterized by a shorter duration of ischemia or obtained with dMCAO or CCAo alone. The BBB permeability was measured by quantifying Evans blue dye (EBD) extravasation, as this tracer has been shown to be more sensitive for the detection of early-phase BBB disruption compared to other intravascular tracers that are more appropriate for detecting late-phase BBB disruption. We showed that a 1 h-long treatment with isoflurane-anesthesia induced marked hypothermia and attenuated the peak of BBB disruption when administered 6 h after the onset of dMCAo/CCAo-induced ischemia. We also demonstrated that the inhibitory effect of isoflurane was hypothermia-dependent because the same treatment had no effect on ischemic BBB disruption when the mouse body temperature was maintained at 37°C. Importantly, inhibiting the peak of BBB disruption by hypothermia had no effect on the volume of brain infarct 24 h post-ischemia. In conclusion, inhibiting the peak of BBB disruption is not an effective neuroprotective strategy, especially in comparison

  5. The Design of the Valsartan for Attenuating Disease Evolution in Early Sarcomeric Hypertrophic Cardiomyopathy (VANISH) Trial.

    Science.gov (United States)

    Ho, Carolyn Y; McMurray, John J V; Cirino, Allison L; Colan, Steven D; Day, Sharlene M; Desai, Akshay S; Lipshultz, Steven E; MacRae, Calum A; Shi, Ling; Solomon, Scott D; Orav, E John; Braunwald, Eugene

    2017-05-01

    Hypertrophic cardiomyopathy (HCM) is often caused by sarcomere gene mutations, resulting in left ventricular hypertrophy (LVH), myocardial fibrosis, and increased risk of sudden cardiac death and heart failure. Studies in mouse models of sarcomeric HCM demonstrated that early treatment with an angiotensin receptor blocker (ARB) reduced development of LVH and fibrosis. In contrast, prior human studies using ARBs for HCM have targeted heterogeneous adult cohorts with well-established disease. The VANISH trial is testing the safety and feasibility of disease-modifying therapy with an ARB in genotyped HCM patients with early disease. A randomized, placebo-controlled, double-blind clinical trial is being conducted in sarcomere mutation carriers, 8 to 45 years old, with HCM and no/minimal symptoms, or those with early phenotypic manifestations but no LVH. Participants are randomly assigned to receive valsartan 80 to 320 mg daily (depending on age and weight) or placebo. The primary endpoint is a composite of 9 z-scores in domains representing myocardial injury/hemodynamic stress, cardiac morphology, and function. Total z-scores reflecting change from baseline to final visits will be compared between treatment groups. Secondary endpoints will assess the impact of treatment on mutation carriers without LVH, and analyze the influence of age, sex, and genotype. The VANISH trial is testing a new strategy of disease modification for treating sarcomere mutation carriers with early HCM, and those at risk for its development. In addition, further insight into disease mechanisms, response to therapy, and phenotypic evolution will be gained. Copyright © 2017. Published by Elsevier Inc.

  6. SAG-UPS attenuates proapoptotic SARM and Noxa to confer survival advantage to early hepatocellular carcinoma.

    Science.gov (United States)

    Chang, S C; Choo, W Q W; Toh, H C; Ding, J L

    2015-01-01

    Hepatocellular carcinoma (HCC) is a deadly cancer because of its commonly late diagnosis and limited treatment options. SAG (sensitive to apoptosis gene)-dependent UPS (ubiquitin-proteasome system) is a key switch between immune-mediated apoptosis and overactivation-mediated protumorigenesis, prompting us to hypothesize that SAG-UPS modulates chronic inflammation-induced tumorigenesis. Here, we investigated the molecular mechanism by which SAG-UPS regulates death/survival of liver cancer cells. By retrospective studies, we found reciprocal expressions of anti-/proapoptotic factors: SAG/SARM and SAG/Noxa in human primary HCC tissues - the antiapoptotic SAG was significantly upregulated whereas the proapoptotic SARM and Noxa were markedly downregulated, suggesting their involvement in hepatocarcinogenesis. Upregulated SAG-UPS effectively manipulates the levels of high-molecular-weight ubiquitinated SARM and Noxa in carcinoma tissues compared with corresponding normal tissues. SAG-overexpressing HCC cell lines display reduced SARM and Noxa (but not Bcl-2, Bax and Bcl-xL), suggesting that SARM and Noxa are specific substrates of SAG-dependent ubiquitination. SARM overexpression activated caspase-3 and caspase-9, reducing cell viability. SAG knockdown significantly elevated apoptosis with increased cytosolic cytochrome c, confirming SAG-mediated antiapoptosis in HCC. SAG overexpression stimulated protumorigenic cytokines, IL-1β, IL-6 and TNF, but not antitumorigenic IL-12p40 and anti-inflammatory IL-10. This is consistent with higher proinflammatory cytokines (IL-1β, IL-6 and TNF) in hepatoma compared with healthy tissues. Altogether, early stage-upregulated SAG-UPS exacerbates hepatocarcinogenesis progression, through: (1) ubiquitination-mediated degradation of proapoptotic SARM and Noxa; and (2) production of protumorigenic cytokines that induce a protumorigenic microenvironment, conferring survival advantage to HCC cells. Thus, we propose SAG-UPS to be an early

  7. Early Transcriptional Signatures of the Immune Response to a Live Attenuated Tetravalent Dengue Vaccine Candidate in Non-human Primates

    Science.gov (United States)

    Strouts, Fiona R.; Popper, Stephen J.; Partidos, Charalambos D.; Stinchcomb, Dan T.; Osorio, Jorge E.; Relman, David A.

    2016-01-01

    Background The development of a vaccine against dengue faces unique challenges, including the complexity of the immune responses to the four antigenically distinct serotypes. Genome-wide transcriptional profiling provides insight into the pathways and molecular features that underlie responses to immune system stimulation, and may facilitate predictions of immune protection. Methodology/Principal Findings In this study, we measured early transcriptional responses in the peripheral blood of cynomolgus macaques following vaccination with a live, attenuated tetravalent dengue vaccine candidate, TDV, which is based on a DENV-2 backbone. Different doses and routes of vaccine administration were used, and viral load and neutralizing antibody titers were measured at different time-points following vaccination. All 30 vaccinated animals developed a neutralizing antibody response to each of the four dengue serotypes, and only 3 of these animals had detectable serum viral RNA after challenge with wild-type dengue virus (DENV), suggesting protection of vaccinated animals to DENV infection. The vaccine induced statistically significant changes in 595 gene transcripts on days 1, 3, 5 and 7 as compared with baseline and placebo-treated animals. Genes involved in the type I interferon (IFN) response, including IFI44, DDX58, MX1 and OASL, exhibited the highest fold-change in transcript abundance, and this response was strongest following double dose and subcutaneous (versus intradermal) vaccine administration. In addition, modules of genes involved in antigen presentation, dendritic cell activation, and T cell activation and signaling were enriched following vaccination. Increased abundance of gene transcripts related to T cell activation on day 5, and the type I IFN response on day 7, were significantly correlated with the development of high neutralizing antibody titers on day 30. Conclusions/Significance These results suggest that early transcriptional responses may be

  8. Early Transcriptional Signatures of the Immune Response to a Live Attenuated Tetravalent Dengue Vaccine Candidate in Non-human Primates.

    Directory of Open Access Journals (Sweden)

    Fiona R Strouts

    2016-05-01

    Full Text Available The development of a vaccine against dengue faces unique challenges, including the complexity of the immune responses to the four antigenically distinct serotypes. Genome-wide transcriptional profiling provides insight into the pathways and molecular features that underlie responses to immune system stimulation, and may facilitate predictions of immune protection.In this study, we measured early transcriptional responses in the peripheral blood of cynomolgus macaques following vaccination with a live, attenuated tetravalent dengue vaccine candidate, TDV, which is based on a DENV-2 backbone. Different doses and routes of vaccine administration were used, and viral load and neutralizing antibody titers were measured at different time-points following vaccination. All 30 vaccinated animals developed a neutralizing antibody response to each of the four dengue serotypes, and only 3 of these animals had detectable serum viral RNA after challenge with wild-type dengue virus (DENV, suggesting protection of vaccinated animals to DENV infection. The vaccine induced statistically significant changes in 595 gene transcripts on days 1, 3, 5 and 7 as compared with baseline and placebo-treated animals. Genes involved in the type I interferon (IFN response, including IFI44, DDX58, MX1 and OASL, exhibited the highest fold-change in transcript abundance, and this response was strongest following double dose and subcutaneous (versus intradermal vaccine administration. In addition, modules of genes involved in antigen presentation, dendritic cell activation, and T cell activation and signaling were enriched following vaccination. Increased abundance of gene transcripts related to T cell activation on day 5, and the type I IFN response on day 7, were significantly correlated with the development of high neutralizing antibody titers on day 30.These results suggest that early transcriptional responses may be predictive of development of adaptive immunity to TDV

  9. Early applied electric field stimulation attenuates secondary apoptotic responses and exerts neuroprotective effects in acute spinal cord injury of rats.

    Science.gov (United States)

    Zhang, C; Zhang, G; Rong, W; Wang, A; Wu, C; Huo, X

    2015-04-16

    Injury potential, which refers to a direct current voltage between intact and injured nerve ends, is mainly caused by injury-induced Ca2+ influx. Our previous studies revealed that injury potential increased with the onset and severity of spinal cord injury (SCI), and an application of applied electric field stimulation (EFS) with the cathode distal to the lesion could delay and attenuate injury potential formation. As Ca2+ influx is also considered as a major trigger for secondary injury after SCI, we hypothesize that EFS would protect an injured spinal cord from secondary injury and consequently improve functional and pathological outcomes. In this study, rats were divided into three groups: (1) sham group, laminectomy only; (2) control group, subjected to SCI only; and (3) EFS group, received EFS immediately post-injury with the injury potential modulated to 0±0.5 mV by EFS. Functional recovery of the hind limbs was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. Results revealed that EFS-treated rats exhibited significantly better locomotor function recovery. Luxol fast blue staining was performed to assess the spared myelin area. Immunofluorescence was used to observe the number of myelinated nerve fibers. Ultrastructural analysis was performed to evaluate the size of myelinated nerve fibers. Findings showed that the EFS group rats exhibited significantly less myelin loss and had larger and more myelinated nerve fibers than the control group rats in dorsal corticospinal tract (dCST) 8 weeks after SCI. Furthermore, we found that EFS inhibited the activation of calpain and caspase-3, as well as the expression of Bax, as detected by Western blot analysis. Moreover, EFS decreased cellular apoptosis, as measured by TUNEL, within 4 weeks post-injury. Results suggest that early EFS could significantly reduce spinal cord degeneration and improve functional and historical recovery. Furthermore, these neuroprotective effects may be related to

  10. Astaxanthin protects against early burn-wound progression in rats by attenuating oxidative stress-induced inflammation and mitochondria-related apoptosis

    Science.gov (United States)

    Fang, Quan; Guo, Songxue; Zhou, Hanlei; Han, Rui; Wu, Pan; Han, Chunmao

    2017-01-01

    Burn-wound progression can occur in the initial or peri-burn area after a deep burn injury. The stasis zone has a higher risk of deterioration mediated by multiple factors but is also considered salvageable. Astaxanthin (ATX), which is extracted from some marine organisms, is a natural compound with a strong antioxidant effect that has been reported to attenuate organ injuries caused by traumatic injuries. Hence, we investigated the potential effects of ATX on preventing early burn-wound progression. A classic “comb” burn rat model was established in this study for histological and biological assessments, which revealed that ATX, particularly higher doses, alleviated histological deterioration in the stasis zone. Additionally, we observed dose-dependent improvements in oxidative stress and the release of inflammatory mediators after ATX treatment. Furthermore, ATX dose-dependently attenuated burn-induced apoptosis in the wound areas, and this effect was accompanied by increases in Akt and Bad phosphorylation and a downregulation of cytochrome C and caspase expression. In addition, the administration of Ly 294002 further verified the effect of ATX. In summary, we demonstrated that ATX protected against early burn-wound progression in a rat deep-burn model. This protection might be mediated by the attenuation of oxidative stress-induced inflammation and mitochondria-related apoptosis. PMID:28128352

  11. Joint Inflammation and Early Degeneration Induced by High-Force Reaching Are Attenuated by Ibuprofen in an Animal Model of Work-Related Musculoskeletal Disorder

    Directory of Open Access Journals (Sweden)

    Jeffrey B. Driban

    2011-01-01

    Full Text Available We used our voluntary rat model of reaching and grasping to study the effect of performing a high-repetition and high-force (HRHF task for 12 weeks on wrist joints. We also studied the effectiveness of ibuprofen, administered in the last 8 weeks, in attenuating HRHF-induced changes in these joints. With HRHF task performance, ED1+ and COX2+ cells were present in subchondral radius, carpal bones and synovium; IL-1alpha and TNF-alpha increased in distal radius/ulna/carpal bones; chondrocytes stained with Terminal deoxynucleotidyl Transferase- (TDT- mediated dUTP-biotin nick end-labeling (TUNEL increased in wrist articular cartilages; superficial structural changes (e.g., pannus and reduced proteoglycan staining were observed in wrist articular cartilages. These changes were not present in normal controls or ibuprofen treated rats, although IL-1alpha was increased in reach limbs of trained controls. HRHF-induced increases in serum C1,2C (a biomarker of collagen I and II degradation, and the ratio of collagen degradation to synthesis (C1,2C/CPII; the latter a biomarker of collage type II synthesis were also attenuated by ibuprofen. Thus, ibuprofen treatment was effective in attenuating HRHF-induced inflammation and early articular cartilage degeneration.

  12. Early and transient sodium-hydrogen exchanger isoform 1 inhibition attenuates subsequent cardiac hypertrophy and heart failure following coronary artery ligation.

    Science.gov (United States)

    Kilić, Ana; Huang, Cathy X; Rajapurohitam, Venkatesh; Madwed, Jeffrey B; Karmazyn, Morris

    2014-12-01

    Na(+)/H(+) exchanger 1 (NHE-1) inhibition attenuates the hypertrophic response and heart failure in various experimental models. As the hypertrophic program is rapidly initiated following insult, we investigated whether early and transient administration of a NHE-1 inhibitor will exert salutary effects on cardiomyocyte hypertrophy or heart failure using both in vitro and in vivo approaches. Neonatal cardiomyocytes were treated with the novel, potent, and highly specific NHE-1 inhibitor BIX (N-[4-(1-acetyl-piperidin-4-yl)-3-trifluoromethyl-benzoyl]-guanidine; 100 nM) for 1 hour in the presence of 10 µM phenylephrine, after which the cells were maintained for a further 23 hours in the absence of NHE-1 inhibition. One-hour treatment with the NHE-1 inhibitor prevented phenylephrine-induced hypertrophy, which was associated with prevention of activation of calcineurin, a key component of the hypertrophic process. Experiments were then performed in rats subjected to coronary artery ligation, in which the NHE-1 inhibitor was administered immediately after infarction for a 1-week period followed by a further 5 weeks of sustained coronary artery occlusion in the absence of drug treatment. This approach significantly attenuated left ventricular hypertrophy and improved both left ventricular systolic and diastolic dysfunction, which was also associated with inhibition of calcineurin activation. Our findings indicate that early and transient administration of an NHE-1 inhibitor bestows subsequent inhibition of cardiomyocyte hypertrophy in culture as well as cardiac hypertrophy and heart failure in vivo, suggesting a critical early NHE-1-dependent initiation of the hypertrophic program. The study also suggests a preconditioning-like phenomenon in preventing hypertrophy and heart failure by early and transient NHE-1 inhibition. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  13. Pretreatment of cromolyn sodium prior to reperfusion attenuates early reperfusion injury after the small intestine ischemia in rats

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the effects of Cromolyn Sodium (CS) pretreated prior to reperfusion on the activity of intestinal mucosal mast cells (IMMC) and mucous membrane of the small intestine in ischemia-reperfusion (IR) injury of rats.METHODS: Thirty-two Sprague-Dawley (SD) rats were randomly divided into four groups: sham group (group S), model group (group M), high and low dosage of CS groups, (treated with CS 50 mg/kg or 25 mg/kg,group C1 and C2). Intestinal IR damage was induced by clamping the superior mesenteric artery for 45 min followed by reperfusion for 60 min. CS was intravenouly administrated 15 min before reperfusion. Ultrastructure and counts of IMMC, intestinal structure, the expression of tryptase, levels of malondisldehyde (MDA), TNF-α,histamine and superoxide dismutase (SOD) activity of the small intestine were detected at the end of experiment.RESULTS: The degranulation of IMMC was seen in group M and was attenuated by CS treatment. Chiu's score of group M was higher than the other groups. CS could attenuate the up-regulation of the Chiu's score,the levels of MDA, TNF-α, and expression of tryptase and the down-regulation of SOD activity and histamine concentration. The Chiu's score and MDA content were negatively correlated, while SOD activity was positively correlated to the histamine concentration respectively in the IR groups.CONCLUSION: Pretreated of CS prior to reperfusion protects the small intestine mucous from ischemiareperfusion damage, the mechanism is inhibited IMMC from degranulation.

  14. Injectable hydrogel promotes early survival of induced pluripotent stem cell-derived oligodendrocytes and attenuates longterm teratoma formation in a spinal cord injury model.

    Science.gov (United States)

    Führmann, T; Tam, R Y; Ballarin, B; Coles, B; Elliott Donaghue, I; van der Kooy, D; Nagy, A; Tator, C H; Morshead, C M; Shoichet, M S

    2016-03-01

    Transplantation of pluripotent stem cells and their differentiated progeny has the potential to preserve or regenerate functional pathways and improve function after central nervous system injury. However, their utility has been hampered by poor survival and the potential to form tumors. Peptide-modified biomaterials influence cell adhesion, survival and differentiation in vitro, but their effectiveness in vivo remains uncertain. We synthesized a peptide-modified, minimally invasive, injectable hydrogel comprised of hyaluronan and methylcellulose to enhance the survival and differentiation of human induced pluripotent stem cell-derived oligodendrocyte progenitor cells. Cells were transplanted subacutely after a moderate clip compression rat spinal cord injury. The hydrogel, modified with the RGD peptide and platelet-derived growth factor (PDGF-A), promoted early survival and integration of grafted cells. However, prolific teratoma formation was evident when cells were transplanted in media at longer survival times, indicating that either this cell line or the way in which it was cultured is unsuitable for human use. Interestingly, teratoma formation was attenuated when cells were transplanted in the hydrogel, where most cells differentiated to a glial phenotype. Thus, this hydrogel promoted cell survival and integration, and attenuated teratoma formation by promoting cell differentiation.

  15. Administration of a PTEN inhibitor BPV(pic) attenuates early brain injury via modulating AMPA receptor subunits after subarachnoid hemorrhage in rats.

    Science.gov (United States)

    Chen, Yujie; Luo, Chunxia; Zhao, Mingyue; Li, Qiang; Hu, Rong; Zhang, John H; Liu, Zhi; Feng, Hua

    2015-02-19

    The aim of this study was to investigate whether the phosphatase and tensin homolog deleted on chromosome ten (PTEN) inhibitor dipotassium bisperoxo(pyridine-2-carboxyl) oxovanadate (BPV(pic)) attenuates early brain injury by modulating α-amino-3-hydroxy-5-methyl-4-isoxa-zolep-propionate (AMPA) receptor subunits after subarachnoid hemorrhage (SAH). A standard intravascular perforation model was used to produce the experimental SAH in Sprague-Dawley rats. BPV(pic) treatment (0.2mg/kg) was evaluated for effects on neurological score, brain water content, Evans blue extravasation, hippocampal neuronal death and AMPA receptor subunits alterations after SAH. We found that BPV(pic) is effective in attenuating BBB disruption, lowering edema, reducing hippocampal neural death and improving neurological outcomes. In addition, the AMPA receptor subunit GluR1 protein expression at cytomembrane was downregulated, whereas the expression of GluR2 and GluR3 was upregulated after BPV(pic) treatment. Our results suggest that PTEN inhibited by BPV(pic) plays a neuroprotective role in SAH pathophysiology, possibly by alterations in glutamate AMPA receptor subunits.

  16. Human serum fetuin A/α2HS-glycoprotein level is associated with long-term survival in patients with alcoholic liver cirrhosis, comparison with the Child-Pugh and MELD scores

    Directory of Open Access Journals (Sweden)

    Prohászka Zoltán

    2007-03-01

    Full Text Available Abstract Background Serum concentration of fetuin A/α2HS-glycoprotein (AHSG is a good indicator of liver cell function and 1-month mortality in patients with alcoholic liver cirrhosis and liver cancer. We intended to determine whether decreased serum AHSG levels are associated with long-term mortality and whether the follow-up of serum AHSG levels can add to the predictive value of the Child-Pugh (CP and MELD scores. Methods We determined serum AHSG concentrations in 89 patients by radial immunodiffusion. Samples were taken at the time of enrolment and in the 1st, 3rd, 6th, and the 12th month thereafter. Results Forty-one patients died during the 1-year follow-up period, 37 of them had liver failure. Data of these patients were analysed further. Deceased patients had lower baseline AHSG levels than the 52 patients who survived (293 ± 77 vs. 490 ± 106 μg/ml, mean ± SD, p Conclusion Serum AHSG concentration is a reliable and sensitive indicator of 1-year mortality in patients with alcoholic liver cirrhosis that compares well to the predictive value of CP score and may further improve that of MELD score.

  17. Altered cellular infiltration and cytokine levels during early Mycobacterium tuberculosis sigC mutant infection are associated with late-stage disease attenuation and milder immunopathology in mice

    Directory of Open Access Journals (Sweden)

    McMurray David N

    2008-09-01

    observations suggest that the immunopathology phenotype is associated with the inability to trigger a strong early immune response, resulting in disease attenuation. While macrophages and T cells have been shown to be important in containing M. tuberculosis disease our study has shown that neutrophils may also play an important role in the containment of this organism.

  18. PA-X-associated early alleviation of the acute lung injury contributes to the attenuation of a highly pathogenic H5N1 avian influenza virus in mice.

    Science.gov (United States)

    Hu, Jiao; Mo, Yiqun; Gao, Zhao; Wang, Xiaoquan; Gu, Min; Liang, Yanyan; Cheng, Xin; Hu, Shunlin; Liu, Wenbo; Liu, Huimou; Chen, Sujuan; Liu, Xiaowen; Peng, Daxing; Liu, Xiufan

    2016-08-01

    PA-X is a novel discovered accessory protein encoded by the PA mRNA. Our previous study demonstrated that PA-X decreases the virulence of a highly pathogenic H5N1 strain A/Chicken/Jiangsu/k0402/2010 in mice. However, the underlying mechanism of virulence attenuation associated with PA-X is still unknown. In this study, we compared two PA-X-deficient mutant viruses and the parental virus in terms of induction of pathology and manipulation of host response in the mouse lung, stimulation of cell death and PA nuclear accumulation. We first found that down-regulated PA-X expression markedly aggravated the acute lung injury of the infected mice early on day 1 post-infection (p.i.). We then determined that loss of PA-X expression induced higher levels of cytokines, chemokines and complement-derived peptides (C3a and C5a) in the lung, especially at early time point's p.i. In addition, in vitro assays showed that the PA-X-deficient viruses enhanced cell death and increased expression of reactive oxygen species (ROS) in mammalian cells. Moreover, we also found that PA nuclear accumulation of the PA-X-null viruses accelerated in MDCK cells. These results demonstrate that PA-X decreases the level of complement components, ROS, cell death and inflammatory response, which may together contribute to the alleviated lung injury and the attenuation of the virulence of H5N1 virus in mice.

  19. Early stage attenuation of phase amplitude coupling in the hippocampus and medial prefrontal cortex in a transgenic rat model of AD.

    Science.gov (United States)

    Bazzigaluppi, Paolo; Beckett, Tina L; Koletar, Margaret M; Lai, Aaron Y; Joo, Illsung L; Brown, Mary E; Carlen, Peter L; McLaurin, JoAnne; Stefanovic, Bojana

    2017-08-04

    Alzheimer's disease (AD) is pathologically characterized by amyloid-β peptide (Aβ) accumulation, neurofibrillary tangle formation, and neurodegeneration. Preclinical studies on neuronal impairments associated with progressive amyloidosis have demonstrated some Aβ-dependent neuronal dysfunction including modulation of GABAergic signalling. The present work focuses on the early stage of disease progression and uses TgF344-AD rats that recapitulate a broad repertoire of AD-like pathologies to investigate the neuronal network functioning using simultaneous intracranial recordings from the hippocampus (HPC) and the medial prefrontal cortex (mPFC), followed by pathological analyses of gamma-aminobutyric acid (GABAA ) receptors subunits α1, α5 and δ, and glutamic acid decarboxylases (GAD65 and GAD67). Concomitant to amyloid deposition and tau hyperphosphorylation, low-gamma band power was strongly attenuated in the HPC and mPFC of TgF344-AD rats in comparison to those in non-transgenic littermates. In addition, the phase-amplitude coupling of the neuronal networks in both areas was impaired, evidenced by decreased modulation of theta band phase on gamma band amplitude in TgF344-AD animals. Finally, the gamma coherence between HPC and mPFC was attenuated as well. These results demonstrate significant neuronal network dysfunction at an early stage of AD-like pathology. This network dysfunction precedes the onset of cognitive deficits and is likely driven by Aβ and tau pathologies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Early exercise training normalizes myofilament function and attenuates left ventricular pump dysfunction in mice with a large myocardial infarction

    NARCIS (Netherlands)

    M.C. de Waard (Monique); J. van der Velden (Jolanda); V. Bito (Virginie); S. Ozdemir (Semir); L. Biesmans (Liesbeth); N.M. Boontje (Nicky); D.H. Dekkers (Dick); K. Schoonderwoerd (Kees); J.C.H. Schuurbiers (Johan); R. de Crom (Rini); G.J.M. Stienen (Ger); K.R. Sipido (Karin); J.M.J. Lamers (Jos); D.J.G.M. Duncker (Dirk)

    2007-01-01

    textabstractThe extent and mechanism of the cardiac benefit of early exercise training following myocardial infarction (MI) is incompletely understood, but may involve blunting of abnormalities in Ca-handling and myofilament function. Consequently, we investigated the effects of 8-weeks of voluntary

  1. 不同钙离子浓度的腹膜透析液对腹膜透析患者血清胎球蛋白A水平及动脉粥样硬化的影响%Influences of different calcium concentrations in dialysate on serum fetuin-A and atherosclerosis in patients on peritoneal dialysis

    Institute of Scientific and Technical Information of China (English)

    梁剑波; 王泽彬; 江丽屏

    2011-01-01

    目的 探讨不同Ca2+浓度腹膜透析液对腹膜透析患者血清胎球蛋白A水平和颈动脉粥样硬化的影响,以及两者间的关系.方法 2008年1月至2010年1月本科室收治30例终末期肾病(ESRD)患者,按完全随机法分为生理钙透析液组及普通钙透析液组,分别使用生理钙透析液(Ca2+浓度1.25 mmol/L)和普通钙透析液(Ca2+浓度1.75 mmol/L)进行腹膜透析治疗并随访观察1年.治疗前后检测患者血清高敏C反应蛋白(hs-CRP)、白蛋白(Alb)、甲状旁腺素(PTH)、钙磷乘积(Ca×P)、总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、胎球蛋白A水平,以及超声检测颈动脉斑块进展情况.10例体检的健康正常人作为健康对照组,检测其血清胎球蛋白A水平.结果 治疗前ESRD组与健康对照组血清胎球蛋白A水平分别为(276.20± 17.0)mg/L和(372.10±18.5)mg/L,ESRD组较健康对照组显著降低(P<0.01).治疗前胎球蛋白A高水平组患者心血管事件发生率低于胎球蛋白A低水平组(P<0.05).治疗1年后,生理钙透析液组患者颈动脉斑块进展显著慢于普通钙透析液组(P<0.05).Logistic回归分析显示颈动脉斑块进展与治疗前后血清胎球蛋白A水平变化值(△fetuin-A)有关联(β=0.320,P<0.01).结论 生理钙透析液能够通过稳定血清胎球蛋白A水平延缓动脉粥样硬化进展,减少腹膜透析患者心血管事件的发生.%Objective To investigate the influences of different calcium concentrations in dialysate on serum fetuin-A and carotid atherosclerosis in patients with end stage renal disease (ESRD) who underwent peritoneal dialysis (PD),and examine the association between serum fetuin-A and atherosclerosis.Methods Thirty ESRD patients undergoing PD in our department between January 2008 and January 2010 were enrolled in this study.They were randomly divided into two groups in 1-year followed-up PD with physiological calcium dialysate( [Ca2

  2. Early interference with p44/42 mitogen-activated protein kinase signaling in hypothalamic paraventricular nucleus attenuates angiotensin II-induced hypertension.

    Science.gov (United States)

    Yu, Yang; Xue, Bao-Jian; Zhang, Zhi-Hua; Wei, Shun-Guang; Beltz, Terry G; Guo, Fang; Johnson, Alan Kim; Felder, Robert B

    2013-04-01

    Blood-borne angiotensin II (ANG II) can upregulate p44/42 mitogen-activated protein kinase (MAPK) signaling and ANG II type-1 receptors in the hypothalamic paraventricular nucleus (PVN), a critical cardiovascular and autonomic center. We tested the hypothesis that brain p44/42 MAPK signaling contributes to the development of ANG II-induced hypertension. The ANG II infusion (120 ng/kg per min, subcutaneously) induced increases in phosphorylated p44/42 MAPK and ANG II type-1 receptors in the PVN after 1 week, before the onset of hypertension, that were sustained as hypertension developed during a 2- or 3-week infusion protocol. Bilateral PVN microinjections of small interfering RNAs for p44/42 MAPK, at the onset of the ANG II infusion or 1 week later, prevented the early increase in p44/42 MAPK activity. The early treatment normalized ANG II type-1 receptor expression in the PVN and attenuated the hypertensive response to the 2-week infusion of ANG II. The later small interfering RNA microinjections had a transient effect on ANG II type-1 receptor expression in PVN and no effect on the hypertensive response to the 3-week infusion of ANG II. The early treatment also normalized the pressure response to ganglionic blockade. The ANG II infusion induced increases in mRNA for proinflammatory cytokines that were not affected by either small interfering RNA treatment. These results suggest that the full expression of ANG II-induced hypertension depends on p44/42 MAPK-mediated effects. A potential role for p44/42 MAPK in modulating the ANG II-induced central inflammatory response might also be considered. MAPK signaling in PVN may be a novel target for early intervention in the progression of ANG II-dependent hypertension.

  3. Early restriction of alphavirus replication and dissemination contributes to age-dependent attenuation of systemic hyperinflammatory disease.

    Science.gov (United States)

    Ryman, Kate D; Gardner, Christina L; Meier, Kathryn C; Biron, Christine A; Johnston, Robert E; Klimstra, William B

    2007-02-01

    Severity of alphavirus infection in humans tends to be strongly age-dependent and several studies using laboratory-adapted Sindbis virus (SB) AR339 strains have indicated that SB-induced disease in mice is similarly contingent upon host developmental status. In the current studies, the consensus wild-type SB, TR339, and in vivo imaging technology have been utilized to examine virus replication and disease manifestations in mice infected subcutaneously at 5 days of age (5D) vs 11D. Initial virulence studies with TR339 indicated that this age range is coincident with rapid transition from fatal to non-fatal outcome. Fatal infection of 5D mice is characterized by high-titre serum viraemia, extensive virus replication in skin, fibroblast connective tissue, muscle and brain, and hyperinflammatory cytokine induction. In contrast, 11D-infected mice experience more limited virus replication and tissue damage and develop mild, immune-mediated pathologies including encephalitis. These results further establish the linkage between hyperinflammatory cytokine induction and fatal outcome of infection. In vivo imaging using luciferase-expressing viruses and non-propagative replicons revealed that host development results in a restriction of virus replication within individual infected cells that is manifested as a delay in reduction of virus replication in the younger mice. Thus, an important contributing factor in age-dependent resistance to alphavirus infection is restriction of replication within first infected cells in peripheral tissues, which may augment other developmentally regulated attenuating effects, such as increasing neuronal resistance to virus infection and apoptotic death.

  4. Perioperative pentoxifylline therapy attenuates early postoperative neuro-cognitive decline in patients undergoing coronary artery bypass grafting surgery using cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Sambhunath Das

    2015-01-01

    Full Text Available Background: Postoperative cognitive decline (POCD after coronary artery bypass grafting (CABG is a common problem. Studies show that pentoxifylline administration reduces inflammation induced by cardiopulmonary bypass and brain injury after ischaemia. Hence the perioperative use of pentoxifylline in attenuating POCD was evaluated in the study. Materials and Methods: Eighty patients were divided randomly into two groups from 106 patients scheduled for CABG surgery. The study group was administered pentoxifylline 400 mg twice daily orally from day of admission to 7th day after surgery, whereas the control group patients received placebo. Neurocognitive assessment was assessed by an independent clinical psychologist one day after admission to hospital and again on 7th postoperative day. The data was analyzed and a P < 0.05 was considered significant results. Results: Pentoxifylline-treated group showed no statistically significant difference in animal naming test scores (10.3 ± 2.2 versus 9.4 ± 2.5, P = 0.07, digit symbol substitution test (26.1 ± 7.47 vs 22.2 ± 6.07, P = 0.09 and 8 subtests of Post Graduate Institute-memory scale. The control group had significant POCD as detected by animal naming test (10.5 ± 3.7 versus 8.6 ± 3.9, P = 0.008, digit symbol substitution test (20.2 ± 8.2 versus 14.7 ± 8.9, P = 0.008 and five subtests of memory scale (P = 0.01, 0.04, 0.003, 0.005 and 0.02. The incidence of POCD was 50% in placebo-treated group compared to 22.5% in pentoxifylline group. Conclusions: The perioperative use of pentoxifylline attenuates the early postoperative neurocognitive decline after CABG using cardiopulmonary bypass.

  5. Neuroprotective Roles of l-Cysteine in Attenuating Early Brain Injury and Improving Synaptic Density via the CBS/H2S Pathway Following Subarachnoid Hemorrhage in Rats.

    Science.gov (United States)

    Li, Tong; Wang, Lingxiao; Hu, Quan; Liu, Song; Bai, Xuemei; Xie, Yunkai; Zhang, Tiantian; Bo, Shishi; Gao, Xiangqian; Wu, Shuhua; Li, Gang; Wang, Zhen

    2017-01-01

    l-Cysteine is a semi-essential amino acid and substrate for cystathionine-β-synthase (CBS) in the central nervous system. We previously reported that NaHS, an H2S donor, significantly alleviated brain damage after subarachnoid hemorrhage (SAH) in rats. However, the potential therapeutic value of l-cysteine and the molecular mechanism supporting these beneficial effects have not been determined. This study was designed to investigate whether l-cysteine could attenuate early brain injury following SAH and improve synaptic function by releasing endogenous H2S. Male Wistar rats were subjected to SAH induced by cisterna magna blood injection, and l-cysteine was intracerebroventricularly administered 30 min after SAH induction. Treatment with l-cysteine stimulated CBS activity in the prefrontal cortex (PFC) and H2S production. Moreover, l-cysteine treatment significantly ameliorated brain edema, improved neurobehavioral function, and attenuated neuronal cell death in the PFC; these effects were associated with a decrease in the Bax/Bcl-2 ratio and the suppression of caspase-3 activation 48 h after SAH. Furthermore, l-cysteine treatment activated the CREB-brain-derived neurotrophic factor (BDNF) pathway and intensified synaptic density by regulating synapse proteins 48 h after SAH. Importantly, all the beneficial effects of l-cysteine in SAH were abrogated by amino-oxyacetic acid, a CBS inhibitor. Based on these findings, l-cysteine may play a neuroprotective role in SAH by inhibiting cell apoptosis, upregulating CREB-BDNF expression, and promoting synaptic structure via the CBS/H2S pathway.

  6. Neuroprotective Roles of l-Cysteine in Attenuating Early Brain Injury and Improving Synaptic Density via the CBS/H2S Pathway Following Subarachnoid Hemorrhage in Rats

    Directory of Open Access Journals (Sweden)

    Gang Li

    2017-05-01

    Full Text Available l-Cysteine is a semi-essential amino acid and substrate for cystathionine-β-synthase (CBS in the central nervous system. We previously reported that NaHS, an H2S donor, significantly alleviated brain damage after subarachnoid hemorrhage (SAH in rats. However, the potential therapeutic value of l-cysteine and the molecular mechanism supporting these beneficial effects have not been determined. This study was designed to investigate whether l-cysteine could attenuate early brain injury following SAH and improve synaptic function by releasing endogenous H2S. Male Wistar rats were subjected to SAH induced by cisterna magna blood injection, and l-cysteine was intracerebroventricularly administered 30 min after SAH induction. Treatment with l-cysteine stimulated CBS activity in the prefrontal cortex (PFC and H2S production. Moreover, l-cysteine treatment significantly ameliorated brain edema, improved neurobehavioral function, and attenuated neuronal cell death in the PFC; these effects were associated with a decrease in the Bax/Bcl-2 ratio and the suppression of caspase-3 activation 48 h after SAH. Furthermore, l-cysteine treatment activated the CREB–brain-derived neurotrophic factor (BDNF pathway and intensified synaptic density by regulating synapse proteins 48 h after SAH. Importantly, all the beneficial effects of l-cysteine in SAH were abrogated by amino-oxyacetic acid, a CBS inhibitor. Based on these findings, l-cysteine may play a neuroprotective role in SAH by inhibiting cell apoptosis, upregulating CREB–BDNF expression, and promoting synaptic structure via the CBS/H2S pathway.

  7. Negative modulation of GABAA α5 receptors by RO4938581 attenuates discrete sub-chronic and early postnatal phencyclidine (PCP)-induced cognitive deficits in rats.

    Science.gov (United States)

    Redrobe, John P; Elster, Lisbeth; Frederiksen, Kristen; Bundgaard, Christoffer; de Jong, Inge E M; Smith, Garrick P; Bruun, Anne Techau; Larsen, Peter H; Didriksen, Michael

    2012-06-01

    A growing body of evidence suggests that negative modulation of γ-aminobutyric acid (GABA) GABA(A) α5 receptors may be a promising strategy for the treatment of certain facets of cognitive impairment; however, selective modulators of GABA(A) α5 receptors have not yet been tested in "schizophrenia-relevant" cognitive assay/model systems in animals. The objectives of this study were to investigate the potential of RO4938581, a negative modulator of GABA(A) α5 receptors, and to attenuate cognitive impairments induced following sub-chronic (sub-PCP) and early postnatal PCP (neo-PCP) administration in the novel object recognition (NOR) and intra-extradimensional shift (ID/ED) paradigms in rats. Complementary in vitro, ex vivo and in vivo studies were performed to confirm negative modulatory activity of RO4938581 and to investigate animal model validity, concept validity and potential side effect issues, respectively. In vitro studies confirmed the reported negative modulatory activity of RO4938581, whilst immunohistochemical analyses revealed significantly reduced parvalbumin-positive cells in the prefrontal cortex of sub-PCP- and neo-PCP-treated rats. RO4938581 (1 mg/kg) ameliorated both sub-PCP- and neo-PCP-induced cognitive deficits in NOR and ID/ED performance, respectively. In contrast, QH-II-066 (1 and 3 mg/kg), a GABA(A) α5 receptor positive modulator, impaired cognitive performance in the NOR task when administered to vehicle-treated animals. Additional studies revealed that both RO4938581 (1 mg/kg) and QH-II-066 (1 and 3 mg/kg) attenuated amphetamine-induced hyperactivity in rats. Taken together, these novel findings suggest that negative modulation of GABA(A) α5 receptors may represent an attractive treatment option for the cognitive impairments, and potentially positive symptoms, associated with schizophrenia.

  8. Growth attenuation with developmental schedule progression in embryos and early larvae of Sterechinus neumayeri raised under elevated CO2.

    Directory of Open Access Journals (Sweden)

    Pauline C Yu

    Full Text Available The Southern Ocean, a region that will be an ocean acidification hotspot in the near future, is home to a uniquely adapted fauna that includes a diversity of lightly-calcified invertebrates. We exposed the larvae of the echinoid Sterechinus neumayeri to environmental levels of CO(2 in McMurdo Sound (control: 410 µatm, Ω = 1.35 and mildly elevated pCO(2 levels, both near the level of the aragonite saturation horizon (510 µatm pCO(2, Ω = 1.12, and to under-saturating conditions (730 µatm, Ω = 0.82. Early embryological development was normal under these conditions with the exception of the hatching process, which was slightly delayed. Appearance of the initial calcium carbonate (CaCO(3 spicule nuclei among the primary mesenchyme cells of the gastrulae was synchronous between control and elevated pCO(2 treatments. However, by prism (7 days after the initial appearance of the spicule nucleus, elongating arm rod spicules were already significantly shorter in the highest CO(2 treatment. Unfed larvae in the 730 µatm pCO(2 treatment remained significantly smaller than unfed control larvae at days 15-30, and larvae in the 510 µatm treatment were significantly smaller at day 20. At day 30, the arm lengths were more differentiated between 730 µatm and control CO(2 treatments than were body lengths as components of total length. Arm length is the most plastic morphological aspect of the echinopluteus, and appears to exhibit the greatest response to high pCO(2/low pH/low carbonate, even in the absence of food. Thus, while the effects of elevated pCO(2 representative of near future climate scenarios are proportionally minor on these early developmental stages, the longer term effects on these long-lived invertebrates is still unknown.

  9. Prostaglandin E2 EP4 Receptor Activation Attenuates Neuroinflammation and Early Brain Injury Induced by Subarachnoid Hemorrhage in Rats.

    Science.gov (United States)

    Xu, Jie; Xu, Zhen; Yan, Ai

    2017-02-27

    Activation of E prostanoid 4 receptor (EP4) shows neuroprotective effects in multiple central nervous system (CNS) lesions, but the roles of EP4 receptor in subarachnoid hemorrhage (SAH) are not explored. This study was designed to research the effects of EP4 modulation on early brain injury (EBI) after experimental SAH in rats. We found that the administration of EP4 selective agonist AE1-329 significantly improved neurological dysfunction, blood brain barrier (BBB) damage and brain edema at 24 h after SAH. Furthermore, AE1-329 obviously reduced the number of activated microglia and the mRNA and protein levels of pro-inflammatory cytokines, and increased Ser1177 phosphorylated endothelial nitric oxide synthase (Ser1177 p-eNOS). Moreover, AE1-329 significantly reduced the number of TUNEL-positive cells and active caspase-3 in cortex after SAH. The EP4 selective antagonist AE3-208 was also administrated and the opposite effects were achieved. Our results indicate that activation of EP4 protects brain from EBI through downregulating neuroinflammation reaction after SAH.

  10. Human Adipose-derived Mesenchymal Stem Cells Attenuate Early Stage of Bleomycin Induced Pulmonary Fibrosis: Comparison with Pirfenidone

    Science.gov (United States)

    Reddy, Manoj; Fonseca, Lyle; Gowda, Shashank; Chougule, Basavraj; Hari, Aarya; Totey, Satish

    2016-01-01

    Background and Objectives Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible, invariably fatal fibrotic lung disease with no lasting option for therapy. Mesenchymal stem cells (MSCs) could be a promising modality for the treatment of IPF. Aim of the study was to investigate improvement in survivability and anti-fibrotic efficacy of human adipose-derived mesenchymal stem cells (AD-MSCs) in comparison with pirfenidone in the bleomycin-induced pulmonary fibrosis model. Methods Human AD-MSCs were administered intravenously on day 3, 6 and 9 after an intra-tracheal challenge with bleomycin, whereas, pirfenidone was given orally in drinking water at the rate of 100 mg/kg body weight three times a day daily from day 3 onward. AD-MSCs were labelled with PKH-67 before administration to detect engraftment. Disease severity and improvement was assessed and compared between sham control and vehicle control groups using Kaplan-Meier survival analysis, biochemical and molecular analysis, histopathology and high resolution computed tomography (HRCT) parameters at the end of study. Results Results demonstrated that AD-MSCs significantly increase survivability; reduce organ weight and collagen deposition better than pirfenidone group. Histological analyses and HRCT of the lung revealed that AD-MSCs afforded protection against bleomycin induced fibrosis and protect architecture of the lung. Gene expression analysis revealed that AD-MSCs potently suppressed pro-fibrotic genes induced by bleomycin. More importantly, AD-MSCs were found to inhibit pro-inflammatory related transcripts. Conclusions Our results provided direct evidence that AD-MSC-mediated immunomodulation and anti-fibrotic effect in the lungs resulted in marked protection in pulmonary fibrosis, but at an early stage of disease. PMID:27871152

  11. Delayed hyperoxic ventilation attenuates oxygen-induced free radical accumulation during early reperfusion after global brain ischemia.

    Science.gov (United States)

    Wang, Yan; Yuan, Li; Liu, Ping; Zhao, Min

    2015-02-11

    To compare the effect of immediate and delayed administration of oxygen on the accumulation of free radicals in ischemia-reperfusion animal models. Thirty-two adult male Mongolian gerbils with microdialysis probes implanted in the right hippocampal CA1 were divided randomly into four groups (eight each). One group was sham-operated (Sham group) whereas the other three groups were subjected to 10 min bilateral carotid artery occlusion (BCAO). BCAO-treated animals were then subjected to the following: (a) immediate 30% O2 (near normoxia, NO group), (b) immediate 100% O2 (hyperoxia, HO group), and (c) 30% O2 for 60 min, followed by 100% O2 for 60 min (delayed hyperoxia, DHO group). Hippocampal accumulation of hydroxyl radicals (•OH) during reperfusion was estimated by measuring 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA in microdialysis perfusate. Hippocampi were removed 2 h after perfusion to measure malondialdehyde, pyruvate dehydrogenase activity, indices of lipid peroxidation, and cellular respiration. At 24 h after BCAO, the histology of hippocampi was analyzed to rate the injury. Immediately after the onset of reperfusion, all groups showed markedly elevated DHBA, which returned to baseline over 1-2 h. Compared with the NO group, the HO group showed significantly higher peak DHBA and slower recovery. In contrast, the DHO group was not significantly different from the NO group in terms of the DHBA level. DHO animals also showed significantly lower hippocampal malondialdehyde accumulation and higher pyruvate dehydrogenase activity at 2 h after reperfusion versus the HO group. Histology analysis also showed animals in the DHO group with ameliorated injury compared with the HO group. Hydroxyl radical accumulation was more sensitive to O2 during early reperfusion. Delayed hyperoxia may re-establish oxidative metabolism while minimizing oxidative stress after CA.

  12. Topiramate attenuates early brain injury following subarachnoid haemorrhage in rats via duplex protection against inflammation and neuronal cell death.

    Science.gov (United States)

    Tian, Yong; Guo, Song-Xue; Li, Jian-Ru; Du, Hang-Gen; Wang, Chao-Hui; Zhang, Jian-Min; Wu, Qun

    2015-10-05

    Early brain injury (EBI) following aneurysmal subarachnoid haemorrhage (SAH) insults contributes to the poor prognosis and high mortality observed in SAH patients. Topiramate (TPM) is a novel, broad-spectrum, antiepileptic drug with a reported protective effect against several brain injuries. The current study aimed to investigate the potential of TPM for neuroprotection against EBI after SAH and the possible dose-dependency of this effect. An endovascular perforation SAH model was established in rats, and TPM was administered by intraperitoneal injection after surgery at three different doses (20mg/kg, 40mg/kg, and 80mg/kg). The animals' neurological scores and brain water content were evaluated, and ELISA, Western blotting and immunostaining assays were conducted to assess the effect of TPM. The results revealed that TPM lowers the elevated levels of myeloperoxidase and proinflammatory mediators observed after SAH in a dose-related fashion, and the nuclear factor-kappa B (NF-κB) signalling pathway is the target of neuroinflammation regulation. In addition, TPM ameliorated SAH-induced cortical neuronal apoptosis by influencing Bax, Bcl-2 and cleaved caspase-3 protein expression, and the effect of TPM was enhanced in a dose-dependent manner. Various dosages of TPM also upregulated the protein expression of the γ-aminobutyric acid (GABA)-ergic signalling molecules, GABAA receptor (GABAAR) α1, GABAAR γ2, and K(+)-Cl(-) co-transporter 2 (KCC2) together and downregulated Na(+)-K(+)-Cl(-) co-transporter 1 (NKCC1) expression. Thus, TPM may be an effective neuroprotectant in EBI after SAH by regulating neuroinflammation and neuronal cell death.

  13. PORTAL AND ARTERIAL FLUSHING WITH HTK AND TACROLIMUS CAN ATTENUATE THE INCIDENCE OF EARLY LIVER ALLOGRAFT DYSFUNCTION

    Directory of Open Access Journals (Sweden)

    A. E. Shcherba

    2015-01-01

    Full Text Available It was shown that Tacrolimus (Tac can suppress infl ammation and immune response involved in liver ischemia-reperfusion injury (IRI (Kristo I., Transpl Int., 2011. Aim. We hypothesize that back-table arterial and portal liver perfusion with Tac can infl uence the incidence and severity of early allograft dysfunction (EAD. A prospective randomized study was conducted (ClinicalTrials.gov Identifi er: NCT01887171.Materials and methods. Criteria of the inclusion: First liver transplantation from DBD donor with sequential portal-arterial reperfusion. At back-table portal vein and hepatic artery were perfused each by 500 ml of HTK solution containing 20 ng/ml Tac during 10–15 min followed by portal fl ushing with 200 ml 5% solution of Albumin containing 20 ng/ml Tac and by resting of liver in effl uent. No Tac was added in the control group. Primary Outcome: EAD (Olthoff KM, et al. Liver Transpl. 2010 and severe EAD (P.R.Salvalaggio, et al. Transpl. Proceedings, 2012.Results. No difference was found between groups (main vs. control in terms of MELD (16 vs. 16, steatosis (10 vs. 10%, ballooning (45 vs. 40% of liver grafts, recipient age (50 vs. 50 y.o., warm ischemia time (50 vs.50 min and total ischemia time (482.5 vs. 485.0 min. Median donor age was higher in the main group (44.5 vs. 39.0 y.o.. The overall rate of EAD was 27.9%. EAD rate was signifi cantly lower in the main group (6/43 vs. 18/43; p = 0.003. The rate of moderate-to-severe EAD was lower in the main group (1/43 vs. 10/43; p = 0.009. The median levels of AST and ALT in 24 h after reperfusion were signifi cantly lower in the intervention group (1004 vs. 1596; p = 0.03 and 449 vs. 759; p = 0.057.Conclusion. Portal and arterial back-table liver perfusion with HTK solution with Tacrolimus may contribute to lower EAD incidence and severity.

  14. Attenuated psychotic and basic symptom characteristics in adolescents with ultra-high risk criteria for psychosis, other non-psychotic psychiatric disorders and early-onset psychosis.

    Science.gov (United States)

    Lo Cascio, Nella; Saba, Riccardo; Hauser, Marta; Vernal, Ditte Lammers; Al-Jadiri, Aseel; Borenstein, Yehonatan; Sheridan, Eva M; Kishimoto, Taishiro; Armando, Marco; Vicari, Stefano; Fiori Nastro, Paolo; Girardi, Paolo; Gebhardt, Eva; Kane, John M; Auther, Andrea; Carrión, Ricardo E; Cornblatt, Barbara A; Schimmelmann, Benno G; Schultze-Lutter, Frauke; Correll, Christoph U

    2016-10-01

    While attenuated psychotic symptoms (APS) and basic symptoms (BS) are the main current predictors of psychosis in adults, studies in adolescents are scarce. Thus, we (1) described the prevalence and severity of positive, negative, disorganization, general, and basic symptoms in adolescent patients at ultra-high risk for psychosis (UHR), with other non-psychotic psychiatric disorders (PC) and with early-onset psychosis (EOP); and (2) investigated BS criteria in relation to UHR criteria. Sixty-nine 12-18-year-old adolescents (15.3 ± 1.7 years, female = 58.0 %, UHR = 22, PC = 27, EOP = 20) were assessed with the structured interview for prodromal syndromes (SIPS) and the schizophrenia proneness instrument-child and youth version (SPI-CY). Despite similar current and past 12-month global functioning, both UHR and EOP had significantly higher SIPS total and subscale scores compared to PC, with moderate-large effect sizes. Expectedly, UHR had significantly lower SIPS positive symptom scores than EOP, but similar SIPS negative, disorganized, and general symptom scores. Compared to PC, both EOP and UHR had more severe basic thought and perception disturbances, and significantly more often met cognitive disturbances criteria (EOP = 50.0 %, UHR = 40.9 %, PC = 14.8 %). Compared to UHR, both EOP and PC significantly less often met cognitive-perceptive BS criteria (EOP = 35.0 %, UHR = 68.2 %, PC = 25.9 %). BS were significantly more prevalent in both EOP and UHR than PC, and UHR were similar to EOP in symptom domains. Given the uncertain outcome of adolescents at clinical high-risk of psychosis, future research is needed to determine whether the combined assessment of early subjective disturbances with observable APS can improve the accuracy of psychosis prediction.

  15. Nrf2/HO-1 mediates the neuroprotective effect of mangiferin on early brain injury after subarachnoid hemorrhage by attenuating mitochondria-related apoptosis and neuroinflammation.

    Science.gov (United States)

    Wang, Zefeng; Guo, Songxue; Wang, Junxing; Shen, Yuanyuan; Zhang, Jianmin; Wu, Qun

    2017-09-19

    Early brain injury (EBI) is involved in the process of cerebral tissue damage caused by subarachnoid hemorrhage (SAH), and multiple mechanisms, such as apoptosis and inflammation, participate in its development. Mangiferin (MF), a natural C-glucoside xanthone, has been reported to exert beneficial effects against several types of organ injury by influencing various biological progresses. The current study aimed to investigate the potential of MF to protect against EBI following SAH via histological and biological assessments. A rat perforation model of SAH was established, and MF was subsequently administered via intraperitoneal injection at a low and a high dose. High-dose MF significantly lowered the mortality of SAH animals and ameliorated their neurological deficits and brain edema. MF also dose-relatedly attenuated SAH-induced oxidative stress and decreased cortical cell apoptosis by influencing mitochondria-apoptotic proteins. In addition, MF downregulated the activation of the NLRP3 inflammasome and NF-κB as well as the production of inflammatory cytokines, and the expression of Nrf2 and HO-1 was upregulated by MF. The abovementioned findings indicate that MF is neuroprotective against EBI after SAH and Nrf2/HO-1 cascade may play a key role in mediating its effect through regulation of the mitochondrial apoptosis pathway and activation of the NLRP3 inflammasome and NF-κB.

  16. Melatonin Attenuates Early Brain Injury via the Melatonin Receptor/Sirt1/NF-κB Signaling Pathway Following Subarachnoid Hemorrhage in Mice.

    Science.gov (United States)

    Zhao, Lei; Liu, Haixiao; Yue, Liang; Zhang, Jingbo; Li, Xia; Wang, Bodong; Lin, Yan; Qu, Yan

    2017-04-01

    Melatonin (Mel) has been reported to alleviate early brain injury (EBI) following subarachnoid hemorrhage (SAH). The activation of silent information regulator 1 (Sirt1), a histone deacetylase, has been suggested to be beneficial in SAH. However, the precise role of Sirt1 in Mel-mediated protection against EBI following SAH has not been elucidated. The present study aims to evaluate the role of melatonin receptor/Sirt1/nuclear factor-kappa B (NF-κB) in this process. The endovascular perforation SAH model was used in male C57BL/6J mice, and melatonin was administrated intraperitoneally (150 mg/kg). The mortality, SAH grade, neurological score, brain water content, and neuronal apoptosis were evaluated. The expression of Sirt1, acetylated-NF-κB (Ac-NF-κB), Bcl-2, and Bax were detected by western blot. To study the underlying mechanisms, melatonin receptor (MR) antagonist luzindole and Sirt1 small interfering RNA (siRNA) were administrated to different groups. The results suggest that Mel improved the neurological deficits and reduced the brain water content and neuronal apoptosis. In addition, Mel enhanced the expression of Sirt1 and Bcl-2 and decreased the expression of Ac-NF-κB and Bax. However, the protective effects of Mel were abolished by luzindole or Sirt1 siRNA. In conclusion, our results demonstrate that Mel attenuates EBI following SAH via the MR/Sirt1/NF-κB signaling pathway.

  17. Bystander Effect Fuels Human Induced Pluripotent Stem Cell-Derived Neural Stem Cells to Quickly Attenuate Early Stage Neurological Deficits After Stroke.

    Science.gov (United States)

    Eckert, Auston; Huang, Lei; Gonzalez, Rodolfo; Kim, Hye-Sun; Hamblin, Milton H; Lee, Jean-Pyo

    2015-07-01

    : Present therapies for stroke rest with tissue plasminogen activator (tPA), the sole licensed antithrombotic on the market; however, tPA's effectiveness is limited in that the drug not only must be administered less than 3-5 hours after stroke but often exacerbates blood-brain barrier (BBB) leakage and increases hemorrhagic incidence. A potentially promising therapy for stroke is transplantation of human induced pluripotent stem cell-derived neural stem cells (hiPSC-NSCs). To date, the effects of iPSCs on injuries that take place during early stage ischemic stroke have not been well studied. Consequently, we engrafted iPSC-NSCs into the ipsilesional hippocampus, a natural niche of NSCs, at 24 hours after stroke (prior to secondary BBB opening and when inflammatory signature is abundant). At 48 hours after stroke (24 hours after transplant), hiPSC-NSCs had migrated to the stroke lesion and quickly improved neurological function. Transplanted mice showed reduced expression of proinflammatory factors (tumor necrosis factor-α, interleukin 6 [IL-6], IL-1β, monocyte chemotactic protein 1, macrophage inflammatory protein 1α), microglial activation, and adhesion molecules (intercellular adhesion molecule 1, vascular cell adhesion molecule 1) and attenuated BBB damage. We are the first to report that engrafted hiPSC-NSCs rapidly improved neurological function (less than 24 hours after transplant). Rapid hiPSC-NSC therapeutic activity is mainly due to a bystander effect that elicits reduced inflammation and BBB damage. Clinically, cerebral vessel occlusion is rarely permanent because of spontaneous or thrombolytic therapy-mediated reperfusion. These results have clinical implications indicating a much extended therapeutic window for transplantation of human induced pluripotent stem cell-derived neural stem cells (hiPSC-NSCs; 24 hours after stroke as opposed to the 5-hour window with tissue plasminogen activator [tPA]). In addition, there is potential for a synergistic

  18. The relationship of urinary MCP1、 fetuin-A expression and urinary MDA in patients with nephrolithiasis%肾结石患者尿液MCP-1、胎球蛋白-A表达与MDA的关系

    Institute of Scientific and Technical Information of China (English)

    孙春

    2015-01-01

    目的:探讨肾结石患者尿液炎症细胞因子变化以及氧化应激在结石形成中的作用.方法:选择75例草酸钙结石住院患者,随机挑选25例健康人作正常对照组.收集两组人的晨尿,分别运用ELLISA法和TBA法检测尿液中单核细胞趋化蛋白(MCP-1)、胎球蛋白-A (Fetuin-A)及丙二醛(MDA)的含量.结果:MCP-1在结石组含量为212.45 (59.24,673.50)pg/mg cr,在对照组为74.36(22.45,203.57)pg/mg cr,结石组高于对照组(P<0.05);胎球蛋白-A在结石组为320.80(42.28,1819.85)ng/mg cr,在对照组为787.94(187.03,3269.17)ng/mg cr,结石组低于对照组(P<0.05);MDA在结石组高于正常对照组(P<0.05).相关性分析:结石组尿液MCP-1和MDA不相关,r=0.045,P> 0.05;胎球蛋白-A和MDA不相关,r=-0.016,P> 0.05.结论:尿液炎症细胞因子变化和氧化应激损伤可能在肾结石形成中起作用,但是氧化应激损伤可能未参与尿液炎症细胞因子的调节.

  19. Ethyl Pyruvate Attenuates Early Brain Injury Following Subarachnoid Hemorrhage in the Endovascular Perforation Rabbit Model Possibly Via Anti-inflammation and Inhibition of JNK Signaling Pathway.

    Science.gov (United States)

    Lv, Tao; Miao, Yi-Feng; Jin, Yi-Chao; Yang, Shao-Feng; Wu, Hui; Dai, Jiong; Zhang, Xiao-Hua

    2017-02-25

    Early brain injury (EBI) following subarachnoid hemorrhage (SAH) is the main cause to poor outcomes of SAH patients, and early inflammation plays an important role in the acute pathophysiological events. It has been demonstrated that ethyl pyruvate (EP) has anti-inflammatory and neuroprotective effects in various critical diseases, however, the role of EP on EBI following SAH remains to be elucidated. Our study aimed to evaluate the effects of EP on EBI following SAH in the endovascular perforation rabbit model. All rabbits were randomly divided into three groups: sham, SAH + Vehicle (equal volume) and SAH + EP (30 mg/kg/day). MRI was performed to estimate the reliability of the EBI at 24 and 72 h after SAH. Neurological scores were recorded to evaluate the neurological deficit, ELISA kit was used to measure the level of tumor necrosis factor-α (TNF-α), and western blot was used to detect the expression of TNF-α, tJNK, pJNK, bax and bcl-2 at 24 and 72 h after SAH. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Fluoro-jade B (FJB) staining were used to detect neuronal apoptosis and neurodegeneration respectively, meanwhile hematoxylin and eosin (H&E) staining was used to assess the degree of vasospasm. Our results demonstrated that EP alleviated brain tissue injury (characterized by diffusion weighted imaging and T2 sequence in MRI scan), and significantly improved neurological scores at 72 h after SAH. EP decreased the level of TNF-α and downregulated pJNK/tJNK and bax/bcl-2 in cerebral cortex and hippocampus effectively both at 24 and 72 h after SAH. Furthermore, EP reduced TUNEL and FJB positive cells significantly. In conclusion, the present study supported that EP afforded neuroprotective effects possibly via reducing TNF-α expression and inhibition of the JNK signaling pathway. Therefore, EP may be a potent therapeutic agent to attenuate EBI following SAH.

  20. Early

    Directory of Open Access Journals (Sweden)

    Kamel Abd Elaziz Mohamed

    2014-04-01

    Conclusion: Early PDT is recommended for patients who require prolonged tracheal intubation in the ICU as outcomes like the duration of mechanical ventilation length of ICU stay and hospital stay were significantly shorter in early tracheostomy.

  1. Association of serum fetuin-A and fetuin-A gene polymorphism in ...

    African Journals Online (AJOL)

    Dalia A. Maharem

    2013-09-12

    Sep 12, 2013 ... disease–mineral and bone disorder, IMD, intima-media thickness,. RTRs, renal ..... female) or · (1.212, if African American) [49]. (E) Specific laboratory tests: 1. ..... cated, are highly time consuming and require experienced per-.

  2. Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72

    Directory of Open Access Journals (Sweden)

    Johannsson Oskar

    2008-11-01

    Full Text Available Abstract Background Familial adenomatous polyposis (FAP is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations. Methods Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations. Results 10 novel APC gene mutations were identified in 11 families. A broad spectrum of extracolonic manifestations was identified in most of these individuals. Two sisters with an insertion in codon 528 (c.1582_1583insGC both showed severe phenotypes with classical polyposis, upper gastrointestinal polyps and thyroid cancer. A woman with a 3'APC mutation (c.5030_5031insAA developed colon cancer at age 72 as the first manifestation of attenuated FAP. Conclusion With an increasing number of FAP families diagnosed, a broad and variable tumor spectrum and a high frequency of extracolonic manifestations are gradually recognized. We report novel APC mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.

  3. Early post-stressor intervention with minocycline, a second-generation tetracycline, attenuates post-traumatic stress response in an animal model of PTSD.

    Science.gov (United States)

    Levkovitz, Yechiel; Fenchel, Daphna; Kaplan, Zeev; Zohar, Joseph; Cohen, Hagit

    2015-01-01

    We assessed the effects of minocycline, a tetracycline with anti-inflammatory, anti-apoptotic and neuroprotective capacities, in an animal model of post-traumatic stress disorder (PTSD). Rats were exposed to psychogenic stress and treated 1h later with minocycline or saline. Behavioral measures included the elevated plus-maze (EPM) and acoustic startle response (ASR) 7 days post stress-exposure. One day after behavioral testing, animals were exposed to a trauma cue and freezing response was assessed. Local levels of cytokines interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the hippocampus, frontal cortex (FC) and hypothalamus were then examined. Minocycline attenuated anxious-like behaviors in stress-exposed rats. In addition, decreased levels of cytokines were measured in exposed rats treated with minocycline compared to their counterparts treated with saline. This study suggests a potential use of minocycline in preventing physiological and behavioral alternations resulting from acute exposure to psychological stress. As this is the first study to report beneficial outcomes for minocycline treatment in an animal model of PTSD, further investigations of the use of minocycline in stress-related conditions with emphasis on PTSD is needed.

  4. Diffusion-weighted MR imaging of metastatic abdominal and pelvic tumours is sensitive to early changes induced by a VEGF inhibitor using alternative diffusion attenuation models

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Matthew R. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Institute of Cancer Research, Sutton, Surrey (United Kingdom); Messiou, Christina; DeSouza, Nandita [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Royal Marsden NHS Foundation Trust, Department of Radiology, Sutton, Surrey (United Kingdom); Collins, David; Leach, Martin O. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Morgan, Veronica A. [Royal Marsden NHS Foundation Trust, Department of Radiology, Sutton, Surrey (United Kingdom); Tessier, Jean; Young, Helen [Early Clinical Development, AstraZeneca, Macclesfield (United Kingdom)

    2016-05-15

    To assess the utility of diffusion weighted imaging for monitoring early treatment effects associated with a VEGF inhibitor. Twenty-nine patients with metastatic abdominal and pelvic tumours were recruited and imaged with DW-MRI: twice at baseline, and after 7 and 28 days of treatment with cediranib. Tumour measures were derived using mono-exponential, bi-exponential and stretched-exponential models, and parameter repeatability and treatment effects seen after 7 and 28 days were assessed. Correlations with volume changes and DCE-MRI metrics were also assessed. Diffusion coefficient repeatabilities from all models were < 6 %; f and D* (bi-exponential) were 22 % and 44 %; α (stretched-exponential) was 4.2 %. Significant increases in the diffusion coefficients from all models were observed at day 28 but not day 7. Significant decreases in D* and f.D* were observed at day 7 and in f at day 28; significant increases in α were observed at both time-points. Weak correlations between DW-MRI changes and volume changes and DCE-MRI changes were observed. DW-MRI is sensitive to early and late treatment changes caused by a VEGF inhibitor using non-mono-exponential models. Evidence of over-fitting using the bi-exponential model suggests that the stretched-exponential model is best suited to monitor such changes. (orig.)

  5. Physical activity attenuates the mid-adolescent peak in insulin resistance but by late adolescence the effect is lost: a longitudinal study with annual measures from 9-16 years (EarlyBird 66).

    Science.gov (United States)

    Metcalf, Brad S; Hosking, Joanne; Henley, William E; Jeffery, Alison N; Mostazir, Mohammod; Voss, Linda D; Wilkin, Terence J

    2015-12-01

    The aim of this work was to test whether the mid-adolescent peak in insulin resistance (IR) and trends in other metabolic markers are influenced by long-term exposure to physical activity. Physical activity (7 day ActiGraph accelerometry), HOMA-IR and other metabolic markers (glucose, fasting insulin, HbA1c, lipids and BP) were measured annually from age 9 years to 16 years in 300 children (151 boys) from the EarlyBird study in Plymouth, UK. The activity level of each child was characterised, with 95% reliability, by averaging their eight annual physical activity measures. Age-related trends in IR and metabolic health were analysed by multi-level modelling, with physical activity as the exposure measure (categorical and continuous) and body fat percentage (assessed by dual-energy X-ray absorptiometry) and pubertal status (according to age at peak height velocity and Tanner stage) as covariates. The peak in IR at age 12-13 years was 17% lower (p active adolescents independently of body fat percentage and pubertal status. However, this difference diminished progressively over the next 3 years and had disappeared completely by the age of 16 years (e.g. difference was -14% at 14 years, -8% at 15 years and +1% at 16 years; 'physical activity × age(2), interaction, p active group. Our finding that physical activity attenuates IR during mid-adolescence may be clinically important. It remains to be established whether the temporary attenuation in IR during this period has implications for the development of diabetes in adolescence and for future metabolic health generally.

  6. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Hokyung; Kim; Jinchae; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  7. Tracer attenuation in groundwater

    Science.gov (United States)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  8. Residual glycosaminoglycan accumulation in mitral and aortic valves of a patient with attenuated MPS I (Scheie syndrome after 6 years of enzyme replacement therapy: Implications for early diagnosis and therapy

    Directory of Open Access Journals (Sweden)

    Yohei Sato

    2015-12-01

    Full Text Available Mucopolysaccharidosis (MPS is an inherited metabolic disease caused by deficiency of the enzymes needed for glycosaminoglycan (GAG degradation. MPS type I is caused by the deficiency of the lysosomal enzyme alpha-l-iduronidase and is classified into Hurler syndrome, Scheie syndrome, and Hurler–Scheie syndrome based on disease severity and onset. Cardiac complications such as left ventricular hypertrophy, cardiac valve disease, and coronary artery disease are often observed in MPS type I. Enzyme replacement therapy (ERT has been available for MPS type I, but the efficacy of this treatment for cardiac valve disease is unknown. We report on a 56-year-old female patient with attenuated MPS I (Scheie syndrome who developed aortic and mitral stenosis and coronary artery narrowing. The cardiac valve disease progressed despite ERT and she finally underwent double valve replacement and coronary artery bypass grafting. The pathology of the cardiac valves revealed GAG accumulation and lysosomal enlargement in both the mitral and aortic valves. Zebra body formation was also confirmed using electron microscopy. Our results suggest that ERT had limited efficacy in previously established cardiac valve disease. Early diagnosis and initiation of ERT is crucial to avoid further cardiac complications in MPS type I.

  9. DSM-5: ATTENUATED PSYCHOSIS SYNDROME?

    Directory of Open Access Journals (Sweden)

    Eduardo Fonseca-Pedrero

    2013-09-01

    Full Text Available Psychotic syndrome includes several devastating mental disorders characterized by a rupture of higher mental functions. The signs and symptoms of psychosis begin in adolescence or early adulthood and usually begin gradually and progress over time. Attenuated psychosis syndrome is a new DSM-5 diagnostic proposal which deals with identifying people at high-risk mental state (ARMS/UHR which may be a predictor of conversion to psychosis. The potential benefit would be that if psychotic disorder is treated more effectively in its early stages, it could produce a lasting beneficial effect that probably could not be achieved with later intervention. This syndrome has generated intense discussion in specialized scientific and professional forums, crisscrossing arguments in favor and against its inclusion. HRMS is preferentially evaluated in the adolescent or young adult population. HRMS evolution is associated with a higher rate of transition toward nonaffective psychosis, although it can evolve toward other mental disorders, remain stable or remit over time. Empirical evidence shows that early intervention seems to have a certain beneficial effect, although for now the results are still insufficient and contradictory. The lack of specificity of symptoms in predicting psychosis, presence of certain limitations (e.g., stigmatization, results found in early interventions and lack of empirical evidence, have led to include the attenuated psychosis syndrome in the DSM-5 Appendix III. The main benefits and limitations of including this supposed category, possible lessons learned from this type of study and future lines of action are discussed in the light of these findings.

  10. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  11. Planetary Ices Attenuation Properties

    Science.gov (United States)

    McCarthy, Christine; Castillo-Rogez, Julie C.

    In this chapter, we review the topic of energy dissipation in the context of icy satellites experiencing tidal forcing. We describe the physics of mechanical dissipation, also known as attenuation, in polycrystalline ice and discuss the history of laboratory methods used to measure and understand it. Because many factors - such as microstructure, composition and defect state - can influence rheological behavior, we review what is known about the mechanisms responsible for attenuation in ice and what can be inferred from the properties of rocks, metals and ceramics. Since attenuation measured in the laboratory must be carefully scaled to geologic time and to planetary conditions in order to provide realistic extrapolation, we discuss various mechanical models that have been used, with varying degrees of success, to describe attenuation as a function of forcing frequency and temperature. We review the literature in which these models have been used to describe dissipation in the moons of Jupiter and Saturn. Finally, we address gaps in our present knowledge of planetary ice attenuation and provide suggestions for future inquiry.

  12. Frequency Dependent Attenuation Revisited

    CERN Document Server

    Richard, Kowar; Xavier, Bonnefond

    2009-01-01

    The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we study causal equations describing propagation of attenuated pressure waves. We review standard models like frequency power laws and and the thermo-viscous equation. The lack of causality of standard models in the parameter range relevant for photoacoustic imaging requires to derive novel equations. The main ingredients for deriving causal equations are the Kramers-Kronig relation and the mathematical concept of linear system theory. The theoretical results of this work are underpined by numerical experiments.

  13. Tritium Attenuation by Distillation

    Energy Technology Data Exchange (ETDEWEB)

    Wittman, N.E.

    2001-07-31

    The objective of this study was to determine how a 100 Area distillation system could be used to reduce to a satisfactory low value the tritium content of the dilute moderator produced in the 100 Area stills, and whether such a tritium attenuator would have sufficient capacity to process all this material before it is sent to the 400 Area for reprocessing.

  14. Optical Attenuation Coefficient Meter

    Science.gov (United States)

    2016-06-22

    back scattered light 202. The back scattered light 202 travels to the attenuation meter 10 after scattering by thermodynamic density fluctuations and...invention to the precise form disclosed; and obviously many modifications and variations are possible in light of the above teaching . Such

  15. Ultrasonic attenuation in pearlitic steel.

    Science.gov (United States)

    Du, Hualong; Turner, Joseph A

    2014-03-01

    Expressions for the attenuation coefficients of longitudinal and transverse ultrasonic waves are developed for steel with pearlitic microstructure. This type of lamellar duplex microstructure influences attenuation because of the lamellar spacing. In addition, longitudinal attenuation measurements were conducted using an unfocused transducer with 10 MHz central frequency on the cross section of a quenched railroad wheel sample. The dependence of longitudinal attenuation on the pearlite microstructure is observed from the changes of longitudinal attenuation from the quenched tread surface to deeper locations. The results show that the attenuation value is lowest and relatively constant within the quench depth, then increases linearly. The experimental results demonstrate a reasonable agreement with results from the theoretical model. Ultrasonic attenuation provides an important non-destructive method to evaluate duplex microstructure within grains which can be implemented for quality control in conjunction with other manufacturing processes.

  16. An attenuated philosophical gentleman.

    Science.gov (United States)

    Christie, John R R

    2014-06-20

    Dr. Joseph Black had at one time, a house near us to the west. He was a striking and beautiful person; tall, very thin, and cadaverously pale; his hair carefully powdered, though there was little of it except what was collected in a long thin queue; his eyes dark, clear and large, like deep pools of pure water. He wore black speckless clothes, silk stockings, silver buckles, and either a slim green umbrella, or a genteel brown cane. The general frame and air were feeble and slender. The wildest boy respected Black. No lad could be irreverent toward a man so pale, so gentle, so elegant and so illustrious. So he glided, like a spirit, through our rather mischievous sportiveness, unharmed. He died seated, with a bowl of milk upon his knee, of which his ceasing to be did not spill a drop; a departure which it seemed, after the event, might have been foretold of this attenuated philosophical gentleman.

  17. A Citizen's Guide to Monitored Natural Attenuation

    Science.gov (United States)

    Citizen's Guide describing how natural attenuation relies on natural processes to decrease or attenuate concentrations of contaminants in soil and groundwater. Scientists monitor these conditions to make sure natural attenuation is working.

  18. Semiactive control for vibration attenuation

    Energy Technology Data Exchange (ETDEWEB)

    Leitmann, G. [Univ. of California, Berkeley, CA (United States). Coll. of Engineering

    1994-12-31

    With the advent of materials, such as electrorheological fluids, whose material properties can be altered rapidly by means of external stimuli, employing such materials as actuators for the controlled attenuation of undesirable vibrations is now possible. Such control schemes are dubbed semiactive in that they attenuate vibrations whether applied actively or passively. The author investigates various such control schemes, allowing for both separate and joint control of the stiffness and damping characteristics of the material.

  19. Estimation of Water Vapour Attenuation And Rain Attenuation

    Directory of Open Access Journals (Sweden)

    K.Kalyana Srinivas

    2015-04-01

    Full Text Available Attenuation due to and water vapour and rain can severely degrade the radio wave propagation at centimeter or millimeter wavelengths. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. The attenuation will pose a greater problem to communication as the frequency of occurrence of heavy rain increases.In a tropical region, like Malaysia, where excessive rainfall is a common phenomenon throughout the year, the knowledge of the rain attenuation at the frequency of operation is extremely required for the design of a reliable terrestrial and earth space communication link at a particular location.

  20. A two-year history of high bone loading physical activity attenuates ethnic differences in bone strength and geometry in pre-/early pubertal children from a low-middle income country.

    Science.gov (United States)

    Meiring, Rebecca M; Avidon, Ingrid; Norris, Shane A; McVeigh, Joanne A

    2013-12-01

    We examined the interplay between ethnicity and weight-bearing physical activity on the content and volumetric properties of bone in a pre- to early pubertal South African Black and White population. Sixty six children [Black boys, 10.4 (1.4)yrs, n=15; Black girls, 10.1 (1.2)yrs, n=27; White boys, 10.1 (1.1)yrs, n=7; White girls, 9.6 (1.3)yrs, n=17] reported on all their physical activities over the past two years in an interviewer administered physical activity questionnaire (PAQ). All participants underwent a whole body and site-specific DXA scan and we also assessed bone structure and estimated bone strength with pQCT. Children were classified as being either high or low bone loaders based on the cohort's median peak bone strain score estimated from the PAQ. In the low bone loading group, Black children had greater femoral neck bone mineral content (BMC) (2.9 (0.08)g) than White children (2.4 (0.11)g; p=0.05). There were no ethnic differences in the high bone loaders for femoral neck BMC. At the cortical site, the Black low bone loaders had a greater radius area (97.3 (1.3) vs 88.8 (2.6)mm(2); p=0.05) and a greater tibia total area (475.5 (8.7) vs. 397.3 (14.0)mm(2); p=0.001) and strength (1633.7 (60.1) vs. 1271.8 (98.6)mm(3); p=0.04) compared to the White low bone loaders. These measures were not different between the Black low and high bone loaders or between the Black and White high bone loaders. In conclusion, the present study shows that there may be ethnic and physical activity associations in the bone health of Black and White pre-pubertal children and further prospective studies are required to determine the possible ethnic specific response to mechanical loading.

  1. Attenuation in Superconducting Circular Waveguides

    Directory of Open Access Journals (Sweden)

    K. H. Yeap

    2016-09-01

    Full Text Available We present an analysis on wave propagation in superconducting circular waveguides. In order to account for the presence of quasiparticles in the intragap states of a superconductor, we employ the characteristic equation derived from the extended Mattis-Bardeen theory to compute the values of the complex conductivity. To calculate the attenuation in a circular waveguide, the tangential fields at the boundary of the wall are first matched with the electrical properties (which includes the complex conductivity of the wall material. The matching of fields with the electrical properties results in a set of transcendental equations which is able to accurately describe the propagation constant of the fields. Our results show that although the attenuation in the superconducting waveguide above cutoff (but below the gap frequency is finite, it is considerably lower than that in a normal waveguide. Above the gap frequency, however, the attenuation in the superconducting waveguide increases sharply. The attenuation eventually surpasses that in a normal waveguide. As frequency increases above the gap frequency, Cooper pairs break into quasiparticles. Hence, we attribute the sharp rise in attenuation to the increase in random collision of the quasiparticles with the lattice structure.

  2. Photoacoustic Imaging Taking into Account Attenuation

    CERN Document Server

    Kowar, Richard

    2010-01-01

    First, we review existing attenuation models and discuss their causality properties, which we believe to be essential for algorithms for inversion with attenuated data. Then, we survey causality properties of common attenuation models. We also derive integro-differential equations which the attenuated waves are satisfying. In addition we discuss the ill--conditionness of the inverse problem for calculating the unattenuated wave from the attenuated one.

  3. X-Ray Attenuation Cell

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.; Toor, A.

    2000-03-03

    To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3rd-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intensity by many orders of magnitude without increasing the pulse-to-pulse variation. In this report we consider a possible solution for controlled attenuation of the LCLS x-ray radiation. We suggest using for this purpose a windowless gas-filled cell with the differential pumping. Although this scheme is easily realizable in principle, it has to be demonstrated that the attenuator can be made short enough to be practical and that the gas loads delivered to the vacuum line of sight (LOS) are acceptable. We are not going to present a final, optimized design. Instead, we will provide a preliminary analysis showing that the whole concept is robust and is worth further study. The spatial structure of the LCLS x-ray pulse at the location of the attenuator is shown in Fig. 1. The central high-intensity component, due to the FEL, has a FWHM of {approx}100 {micro}m. A second component, due to the undulator's broad band spontaneous radiation is seen as a much lower intensity ''halo'' with a FWHM of 1 mm. We discuss two versions of the attenuation cell. The first is directed towards a controlled attenuation of the FEL up to the 4 orders of magnitude in the intensity, with the spontaneous radiation halo being eliminated by collimators. In the second version, the spontaneous radiation is not sacrificed but the FEL component (as well as the first harmonic of the spontaneous radiation) gets attenuated by a more modest factor up to 100. We will make all the estimates assuming that the gas used in the attenuator is Xenon and that the energy of the FEL is 8.25 keV. At

  4. Attenuation in silica-based optical fibers

    DEFF Research Database (Denmark)

    Wandel, Marie Emilie

    2006-01-01

    In this thesis on attenuation in silica based optical fibers results within three main topics are reported. Spectral attenuation measurements on transmission fibers are performed in the wide wavelength range 290 nm – 1700 nm. The measured spectral attenuation is analyzed with special emphasis...... on absorption peaks in order to investigate the cause of an unusual high attenuation in a series of transmission fibers. Strong indications point to Ni2+ in octahedral coordination as being the cause of the high attenuation. The attenuation of fibers having a high core refractive index is analyzed and the cause...... of the high attenuation measured in such fibers is described as being due to scattering of light on fluctuations of the core diameter. A novel semi-empirical model for predicting the attenuation of high index fibers is presented. The model is shown to be able to predict the attenuation of high index fibers...

  5. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  6. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc bias...

  7. Stormwater Attenuation by Green Roofs

    Science.gov (United States)

    Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.

    2014-12-01

    Innovative municipal stormwater management technologies are urgently required in urban centers. Inadequate stormwater management can lead to excessive flooding, channel erosion, decreased stream baseflows, and degraded water quality. A major source of urban stormwater is unused roof space. Green roofs can be used as a stormwater management tool to reduce roof generated stormwater and generally improve the quality of runoff. With recent legislation in some North American cities, including Toronto, requiring the installation of green roofs on large buildings, research on the effectiveness of green roofs for stormwater management is important. This study aims to assess the hydrologic response of an extensive sedum green roof in London, Ontario, with emphasis on the response to large precipitation events that stress municipal stormwater infrastructure. A green roof rapidly reaches field capacity during large storm events and can show significantly different behavior before and after field capacity. At field capacity a green roof has no capillary storage left for retention of stormwater, but may still be an effective tool to attenuate peak runoff rates by transport through the green roof substrate. The attenuation of green roofs after field capacity is linked to gravity storage, where gravity storage is the water that is temporarily stored and can drain freely over time after field capacity has been established. Stormwater attenuation of a modular experimental green roof is determined from water balance calculations at 1-minute intervals. Data is used to evaluate green roof attenuation and the impact of field capacity on peak flow rates and gravity storage. In addition, a numerical model is used to simulate event based stormwater attenuation. This model is based off of the Richards equation and supporting theory of multiphase flow through porous media.

  8. A Prospective, Randomized Investigation of Plasma First Resuscitation for Traumatic Hemorrhage and Attenuation of Acute Coagulopathy of Trauma

    Science.gov (United States)

    2016-05-01

    Attenuation of Acute Coagulopathy of Trauma . PRINCIPAL INVESTIGATOR: Ernest E. Moore, MD CONTRACTING ORGANIZATION: University of Colorado Denver...Randomized Investigation of “Plasma First Resuscitation” for Traumatic Hemorrhage and Attenuation of Acute Coagulopathy of Trauma . 5b. GRANT NUMBER...NOTES 14. ABSTRACT The COMBAT (Control of Major Bleeding After Trauma ) study is a randomized clinical trial evaluating the early administration of

  9. Ferrite attenuator modulation improves antenna performance

    Science.gov (United States)

    Hooks, J. C.; Larson, S. G.; Shorkley, F. H.; Williams, B. T.

    1970-01-01

    Ferrite attenuator inserted into appropriate waveguide reduces the gain of the antenna element which is causing interference. Modulating the ferrite attenuator to change the antenna gain at the receive frequency permits ground tracking until the antenna is no longer needed.

  10. Stress Potentiates Early and Attenuates Late Stages of Visual Processing

    Science.gov (United States)

    2011-01-19

    A.J.S.). We thank K. Berling, S. Blume, D. Cole, I. Dolski, L. Friedman, J. Koger, J. Nichols, and A. Teche for assistance; and A. Fox, A. Heller , J...monkey. J Neurosci 9:81–93. Qin S, Hermans EJ, van Marle HJ, Luo J, Fernández G (2009) Acute psycho- logical stress reduces working memory-related...Neurosci 11:843– 850. van Marle HJ, Hermans EJ, Qin S, Fernández G (2009) From specificity to sensitivity: how acute stress affects amygdala processing of

  11. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  12. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  13. A Next-generation Genetically Attenuated Plasmodium falciparum Parasite Created by Triple Gene Deletion

    OpenAIRE

    Mikolajczak, Sebastian A.; Lakshmanan, Viswanathan; Fishbaugher, Matthew; Camargo, Nelly; Harupa, Anke; Kaushansky, Alexis; Douglass, Alyse N.; Baldwin, Michael; Healer, Julie; O'Neill, Matthew; Phuong, Thuan; Cowman, Alan; Kappe, Stefan H. I.

    2014-01-01

    Immunization with live-attenuated Plasmodium sporozoites completely protects against malaria infection. Genetic engineering offers a versatile platform to create live-attenuated sporozoite vaccine candidates. We previously generated a genetically attenuated parasite (GAP) by deleting the P52 and P36 genes in the NF54 wild-type (WT) strain of Plasmodium falciparum (Pf p52−/p36− GAP). Preclinical assessment of p52−/p36− GAP in a humanized mouse model indicated an early and severe liver stage gr...

  14. Sodium alginate oligosaccharides attenuate hypertension in spontaneously hypertensive rats fed a low-salt diet.

    Science.gov (United States)

    Ueno, Mai; Tamura, Yuki; Toda, Natsuko; Yoshinaga, Mariko; Terakado, Shouko; Otsuka, Kie; Numabe, Atsushi; Kawabata, Yukari; Murota, Itsuki; Sato, Nobuyuki; Uehara, Yoshio

    2012-01-01

    We investigated the effects of sodium alginate oligosaccharides (alginate) on the development of spontaneous hypertension in rats. Spontaneous hypertensive rats were treated with alginate for 7 weeks. Systolic blood pressure (SBP) and cardiovascular and kidney damage were assessed. Systolic blood pressure increased in SHRs and this elevation was attenuated with alginate treatment. The heart weight tended to decline. Alginate did not change plasma cholesterol levels or urinary sodium excretions. The slightly higher urinary protein excretion in SHRs was not changed with the treatment; however, morphologic glomerular damage was significantly attenuated. Sodium alginate oligosaccharide attenuates spontaneous hypertension in SHRs, and may help prevent early-stage kidney injury.

  15. Novel MEMS variable optical attenuator

    Institute of Scientific and Technical Information of China (English)

    Maosong Wu(吴茂松); Chunsheng Yang(杨春生); Xinhui Mao(茅昕辉); Xiaolin Zhao(赵小林); Bingchu Cai(蔡炳初)

    2003-01-01

    A novel MEMS variable optical attenuator (VOA), which has completely different attenuation mechanismfrom those in literatures, is proposed and demonstrated in this paper. The basic operation principle is thatthe optical power coupled between two initially aligned single-mode fibers will be continuously attenuatedwhile the end of one of the fibers is deflected from the initial position. A micromachined solenoid typeinductor with a U-shaped permalloy magnetic core is used to attract the deflectable fiber that has apermalloy coat on its end. To fabricate the multi-layer three-dimensional inductive component, a newUV-LIGA process for thick photoresists is developed, combining advantages of both SU-8 and AZ-4000series photoresists. The inductive component is approximately 1.7 mm× 1.3 mm×50μm in size and has alow resistance value (~ 2.1Ω). The whole size of the VOA before packaging is 30 mm×2 mm×0.6 mm.The first prototype shows less then 3-dB insertion loss at 0-dB attenuation and nearly 40-dB attenuationrange with less than 20 mW electrical input power at wavelength 1550 nm.

  16. Imaging Rayleigh wave attenuation with USArray

    Science.gov (United States)

    Bao, Xueyang; Dalton, Colleen A.; Jin, Ge; Gaherty, James B.; Shen, Yang

    2016-07-01

    The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity and provide important constraints on the temperature, composition, melt content, and volatile content of the mantle. The surface wave amplitudes that constrain upper-mantle attenuation are sensitive to factors in addition to attenuation, including the earthquake source excitation, focusing and defocusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, Rayleigh wave traveltime and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique, which takes advantage of waveform similarity at nearby stations. Several estimates of Rayleigh wave attenuation and site amplification are generated at each period, using different approaches to separate the effects of attenuation and local site amplification on amplitude. It is assumed that focusing and defocusing effects can be described by the Laplacian of the traveltime field. All approaches identify the same large-scale patterns in attenuation, including areas where the attenuation values are likely contaminated by unmodelled focusing and defocusing effects. Regionally averaged attenuation maps are constructed after removal of the contaminated attenuation values, and the variations in intrinsic shear attenuation that are suggested by these Rayleigh wave attenuation maps are explored.

  17. Magnetoelectric Composite Based Microwave Attenuator

    Science.gov (United States)

    Tatarenko, A. S.; Srinivasan, G.

    2005-03-01

    Ferrite-ferroelectric composites are magnetoelectric (ME) due to their response to elastic and electromagnetic force fields. The ME composites are characterized by tensor permittivity, permeability and ME susceptibility. The unique combination of magnetic, electrical, and ME interactions, therefore, opens up the possibility of electric field tunable ferromagnetic resonance (FMR) based devices [1]. Here we discuss an ME attenuator operating at 9.3 GHz based on FMR in a layered sample consisting of lead magnesium niobate-lead titanate bonded to yttrium iron garnet (YIG) film on a gadolinium gallium garnet substrate. Electrical tuning is realized with the application of a control voltage due to ME effect; the shift is 0-15 Oe as E is increased from 0 to 3 kV/cm. If the attenuator is operated at FMR, the corresponding insertion loss will range from 25 dB to 2 dB. 1. S. Shastry and G. Srinivasan, M.I. Bichurin, V.M. Petrov, A.S. Tatarenko. Phys. Rev. B, 70 064416 (2004). - supported by grants the grants from the National Science Foundation (DMR-0302254), from Russian Ministry of Education (Å02-3.4-278) and from Universities of Russia Foundation (UNR 01.01.026).

  18. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  19. Attenuation map reconstruction from TOF PET data

    CERN Document Server

    Yang, Qingsong; Wang, Ge

    2013-01-01

    To reconstruct a radioactive tracer distribution with positron emission tomography (PET), the background attenuation correction is needed to eliminate image artifacts. Recent research shows that time-of-flight (TOF) PET data determine the attenuation sinogram up to a constant, and its gradient can be computed using an analytic algorithm. In this paper, we study a direct estimation of the sinogram only from TOF PET data. First, the gradient of the attenuation sinogram is estimated using the aforementioned algorithm. Then, a relationship is established to link the differential attenuation sinogram and the underlying attenuation background. Finally, an iterative algorithm is designed to determine the attenuation sinogram accurately and stably. A 2D numerical simulation study is conducted to verify the correctness of our proposed approach.

  20. Attenuation correction in SPECT images using attenuation map estimation with its emission data

    Science.gov (United States)

    Tavakoli, Meysam; Naji, Maryam; Abdollahi, Ali; Kalantari, Faraz

    2017-03-01

    Photon attenuation during SPECT imaging significantly degrades the diagnostic outcome and the quantitative accuracy of final reconstructed images. It is well known that attenuation correction can be done by using iterative reconstruction methods if we access to attenuation map. Two methods have been used to calculate the attenuation map: transmission-based and transmissionless techniques. In this phantom study, we evaluated the importance of attenuation correction by quantitative evaluation of errors associated with each method. For transmissionless approach, the attenuation map was estimated from the emission data only. An EM algorithm with attenuation model was developed and used for attenuation correction during image reconstruction. Finally, a comparison was done between reconstructed images using our OSEM code and analytical FBP method before and after attenuation correction. The results of measurements showed that: our programs are capable to reconstruct SPECT images and correct the attenuation effects. Moreover, to evaluate reconstructed image quality before and after attenuation correction we applied a novel approach using Image Quality Index. Attenuation correction increases the quality and quantitative accuracy in both methods. This increase is independent of activity in quantity factor and decreases with activity in quality factor. In EM algorithm, it is necessary to use regularization to obtain true distribution of attenuation coefficients.

  1. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...... the spatial impulse response, whereas the field cannot readily be found for an attenuating medium. In this paper we present a simulation program capable of calculating the field in a homogeneous attenuating medium. The program splits the aperture into rectangles and uses a far-field approximation for each...

  2. Optimal ultrasonic array focusing in attenuative media.

    Science.gov (United States)

    Ganguli, A; Gao, R X; Liang, K; Jundt, J

    2011-12-01

    This paper presents a parametric study on the efficiency of ultrasound focusing in an attenuative medium, using phased arrays. Specifically, an analytical model of ultrasound wave focusing in a homogeneous, isotropic and attenuative fluid with point sources is presented. Calculations based on the model have shown that in an attenuative medium, an optimum frequency exists for the best focusing performance for a particular size of aperture and focal distance. The effect of different f numbers on the focusing performance in the attenuative medium is further investigated. The information obtained from the analytical model provides insights into the design and installation of a phased transducer array for energy efficient wave focusing.

  3. Attenuation prediction for fade mitigation using neural network with in situ learning algorithm

    Science.gov (United States)

    Roy, Bijoy; Acharya, Rajat; Sivaraman, M. R.

    2012-01-01

    Increasing demand of bandwidth in communication satellites has forced satellite links to be designed in Ku bands and above. But at these frequencies, rain and other tropospheric elements result in large attenuation. To mitigate the tropospheric attenuation of microwave satellite signals above 10 GHz using any standard Fade Mitigation Technique (FMT), it is essential to have a priori knowledge about the level of attenuation. Hence, short-term rain attenuation prediction models play a key role in maintaining the link in which necessary compensation can be applied depending on the early information of attenuation. This paper presents a method of attenuation prediction using Adaptive Artificial Neural Network. Here In situ Learning Algorithm (ILA) has been used to enable the system to track the non-stationary nature of the attenuation. To validate this, Ku Band data, collected at three different sites in India have been used for the purpose of prediction. The performance of the algorithm is determined through the estimation of prediction accuracy by comparing the predicted values with the measured data. Results obtained using the mentioned technique shows considerably good accuracy even up to 20 s of prediction interval with acceptable ratio between the under and over predictions. The prediction performance is evaluated for different prediction intervals. Furthermore the present model is also compared with the persistence model and the relative performance is quantified.

  4. Wideband, 50 dB Attenuation Range Liquid Crystal Based Variable Optical Attenuator

    Institute of Scientific and Technical Information of China (English)

    J.J.; Pan; Henry; He; Eric; Zhang

    2003-01-01

    A compact variable optical attenuator, covering C and L bands with over 50 dB attenuation range, is realized using a single liquid crystal cell with a tilted fused silica coating compensating the cell's small residual birefringence.

  5. Ultrasonic attenuation in cuprate superconductors

    Indian Academy of Sciences (India)

    T Gupta; D M Gaitonde

    2002-05-01

    We calculate the longitudinal ultrasonic attenuation rate (UAR) in clean d-wave superconductors in the Meissner and the mixed phases. In the Meissner phase we calculate the contribution of previously ignored processes involving the excitation of a pair of quasi-holes or quasi-particles. There is a contribution ∝ in the regime B ≪ F ≪ 0 and a contribution ∝ 1/ in the regime F ≪ B ≪ 0. We find that these contributions to the UAR are large and cannot be ignored. In the mixed phase, using a semi-classical description, we calculate the electronic quasi-particle contribution to the UAR which at very low , has a independent term proportional to $\\sqrt{H}$.

  6. Attenuation characteristics of a light attenuator combined by polarizers with different extinction ratios

    Institute of Scientific and Technical Information of China (English)

    Huang Chong; Deng Peng; Zhao Shuang; Chen Hai-Qing

    2011-01-01

    This paper deals with a systematical analysis and an algorithm of attenuation characteristics of a light attenuator combined by n pieces of polarizers(n-LACP)whose extinction ratios are different from each other.The attenuation ratio expression of a two-LACP is deduced. We find that the monotonic attenuation interval depends on the first polarizer and that the attenuation range depends on the second one.For the three-LACP,a method for obtaining a monotonic attenuation interval is proposed.Moreover,the attenuation ratio expression is demonstrated.Analysis and experiment show that when the initial status of the three-LACP is at the maximum output,if the second or third polarizer rotates alone,the minimum attenuation ratios can reach K2-1and K3-1,respectively,and if the first polarizer rotates,a minimum attenuation ratio of K2-1K3-1can be obtained(K1,K2 and K3 represent the extinction ratios of the three polarizers in turn).Furthermore,the attenuation ratio expression of n-LACP and the relevant attenuation characteristics are proposed.The minimum attenuation ratio of an n-LACP is(K2K3...Kn)-1.

  7. Light attenuation on Chlorella vulgaris cells

    Science.gov (United States)

    Krol, Tadeusz; Lotocka, Maria

    1993-12-01

    The laboratory measurements of spectrum of light attenuation on phytoplankton particles i.e. monoculture of unicellural green algae Chlorella vulgaris are presented. The measurements were carried out for alive culture and the cultures subjected to chemical (NaOH) or physical (ultrasounds) modification. The distinct changes in the light attenuation spectrum were a result of modification of the internal cell structures.

  8. DISTURBANCE ATTENUATION FOR UNCERTAIN NONLINEAR CASCADED SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    BI Weiping; MU Xiaowu; SUN Yuqiang

    2004-01-01

    In present paper, the disturbance attenuation problem of uncertain nonlinear cascaded systems is studied. Based on the adding one power integrator technique and recursive design, a feedback controller that solves the disturbance attenuation problem is constructed for uncertain nonlinear cascaded systems with internal stability.

  9. Attenuation coefficients for water quality trading.

    Science.gov (United States)

    Keller, Arturo A; Chen, Xiaoli; Fox, Jessica; Fulda, Matt; Dorsey, Rebecca; Seapy, Briana; Glenday, Julia; Bray, Erin

    2014-06-17

    Water quality trading has been proposed as a cost-effective approach for reducing nutrient loads through credit generation from agricultural or point source reductions sold to buyers facing costly options. We present a systematic approach to determine attenuation coefficients and their uncertainty. Using a process-based model, we determine attenuation with safety margins at many watersheds for total nitrogen (TN) and total phosphorus (TP) loads as they transport from point of load reduction to the credit buyer. TN and TP in-stream attenuation generally increases with decreasing mean river flow; smaller rivers in the modeled region of the Ohio River Basin had TN attenuation factors per km, including safety margins, of 0.19-1.6%, medium rivers of 0.14-1.2%, large rivers of 0.13-1.1%, and very large rivers of 0.04-0.42%. Attenuation in ditches transporting nutrients from farms to receiving rivers is 0.4%/km for TN, while for TP attenuation in ditches can be up to 2%/km. A 95 percentile safety margin of 30-40% for TN and 6-10% for TP, applied to the attenuation per km factors, was determined from the in-stream sensitivity of load reductions to watershed model parameters. For perspective, over 50 km a 1% per km factor would result in 50% attenuation = 2:1 trading ratio.

  10. Antioxidant treatment attenuates lactate production in diabetic nephropathy

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Nielsen, Per Mose; Stokholm Nørlinger, Thomas

    2017-01-01

    The early progression of diabetic nephropathy is notoriously difficult to detect and quantify before the occurrence of substantial histological damage. Recently, hyperpolarized [1-13C]pyruvate has demonstrated increased lactate production in the kidney early after the onset of diabetes, implying......-of-the-art hyperpolarized magnetic resonance (MR) imaging. Ten-week-old female Wistar rats were randomly divided into three groups: healthy controls, untreated diabetic (streptozotocin treatment to induce insulinopenic diabetes), and diabetic, receiving chronic antioxidant treatment with TEMPOL (4-hydroxy-2......-IDEAL spiral sequence. Untreated diabetic rats showed increased renal lactate production compared with that shown by the controls. However, chronic TEMPOL treatment significantly attenuated diabetes-induced lactate production. No significant effects of diabetes or TEMPOL were observed on [13C]alanine levels...

  11. Antioxidant treatment attenuates lactate production in diabetic nephropathy

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Nielsen, Per Mose; Stokholm Nørlinger, Thomas

    2017-01-01

    increased lactate dehydrogenase activity as a consequence of increased nicotinamide adenine dinucleotide substrate availability due to upregulation of the polyol pathway, i.e., pseudohypoxia. In this study, we investigated the role of oxidative stress in mediating these metabolic alterations using state......The early progression of diabetic nephropathy is notoriously difficult to detect and quantify before the occurrence of substantial histological damage. Recently, hyperpolarized [1-13C]pyruvate has demonstrated increased lactate production in the kidney early after the onset of diabetes, implying......-IDEAL spiral sequence. Untreated diabetic rats showed increased renal lactate production compared with that shown by the controls. However, chronic TEMPOL treatment significantly attenuated diabetes-induced lactate production. No significant effects of diabetes or TEMPOL were observed on [13C]alanine levels...

  12. Live attenuated intranasal influenza vaccine.

    Science.gov (United States)

    Esposito, Susanna; Montinaro, Valentina; Groppali, Elena; Tenconi, Rossana; Semino, Margherita; Principi, Nicola

    2012-01-01

    Annual vaccination is the most effective means of preventing and controlling influenza epidemics, and the traditional trivalent inactivated vaccine (TIV) is by far the most widely used. Unfortunately, it has a number of limitations, the most important of which is its poor immunogenicity in younger children and the elderly, the populations at greatest risk of severe influenza. Live attenuated influenza vaccine (LAIV) has characteristics that can overcome some of these limitations. It does not have to be injected because it is administered intranasally. It is very effective in children and adolescents, among whom it prevents significantly more cases of influenza than the traditional TIV. However, its efficacy in adults has not been adequately documented, which is why it has not been licensed for use by adults by the European health authorities. LAIV is safe and well tolerated by children aged > 2 y and adults, but some concerns arisen regarding its safety in younger children and subjects with previous asthma or with recurrent wheezing. Further studies are needed to solve these problems and to evaluate the possible role of LAIV in the annual vaccination of the general population.

  13. Attenuation of diacylglycerol second messengers

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, W.R.; Ganong, B.R.; Bell, R.M.

    1986-05-01

    Diacylglycerol(DAG) derived from phosphatidylinositol activates protein kinase C in agonist-stimulated cells. At least two pathways may contribute to the attenuation of the DAG signal: (1) phosphorylation to phosphatidic acid(PA) by DAG kinase(DGK), and (2) deacylation by DAG and monoacylglycerol lipases. A number of DAG analogs were tested as substrates and inhibitors of partially purified pig brain DGK. Two analogs were potent inhibitors in vitro, 1-monooleoylglycerol(MOG,K/sub I/ = 91 ..mu..M) and diotanoylethyleneglycol (diC/sub 8/EG, K/sub I/ = 58 ..mu..M). These compounds were tested in human platelets. DiC/sub 8/EG inhibited (70 - 100%) (/sup 32/P/sub i/) incorporation into PA in thrombin-stimulated platelets. Under these conditions the DAG signal was somewhat long-lived but was still metabolized, presumably by the lipase pathway. MOG treatment elevated DAG levels up to 4-fold in unstimulated platelets. The DAG formed was in a pool where it did not activate protein kinase C. Thrombin-stimulation of MOG-treated platelets resulted in DAG levels 10-fold higher than control platelets. This appears to be due to the inability of these platelets to metabolize agonist-linked DAG via the lipase pathway. The development of specific inhibitors of DAG kinase and DAG lipase, in conjunction with mass quantification of DAG levels as used here, will provide further insights into the regulation of DAG second messengers.

  14. Early sound distribution in auditorium

    Institute of Scientific and Technical Information of China (English)

    JIANG Guorong; WANG Jiqing

    2000-01-01

    The importance of early sound, i.e., the direct sound and the first reflections, has long been recognized in auditorium design, but the distributions of early sound in auditorium received less investigation in the past. As we know, the early sound level in the audience area varies not only with the source/receiver distance and room constant, but also related with the room geometry, the absorption arrangement and the location of the source and receiver. The early reflections are of discrete components, so it can not be predicted by the diffused field theory. This paper presents the results of measurement in four halls showing the attenuation rates of early sound level with the source/receiver distance are often much larger than the theoretical predictions. Therefore, they may give overestimated results in acoustical design.

  15. Carbon nanotubes attenuate cancer and improve healing

    Science.gov (United States)

    Wailes, Elizabeth Marguerite

    Breast cancer is the most common cancer in American women and the second largest cause of their cancer mortality. Resection of the primary tumor can greatly improve the prognosis, but if any of the cancerous cells remain, the patient is still at risk. This work investigates the ability of high aspect ratio nanoparticles to both heal injured tissue and attenuate cancer cells' aggression. To assess different particles' utility, carbon nanoparticles were evaluated in a fibroblast and collagen gel model of wound contraction, then polymeric nanoparticles were synthesized and tested similarly. The carbon particles, multi-walled nanotubes (MWNT) in particular, performed the best, strongly inhibiting pathological wound contraction, increasing cell viability, and decreasing reactive oxygen species. Later, carbon nanoparticle coatings with or without collagen were tested with breast cancer cells to assess adhesion, migration, and E-cadherin expression of the cells. The collagen-MWNT coatings were able to increase cancer cell adhesion to their substrate, decrease migration, increase E-cadherin expression, and also increase autophagy. The coatings effected all these changes without increasing proliferation of the cancer cells or affecting non-tumorigenic breast cells. To examine how these two sets of results might act together, co-cultures were then created with both fibroblasts and cancer cells in collagen gels with or without MWNT. The cells' movement and matrix metalloproteinase (MMP) expression were measured to gauge the cells' interaction in that environment, as fibroblasts can encourage or suppress metastasis depending on their behavior. The MWNT were able to decrease cancer cell movement, particularly their invasion into the gel, and selectively promote cancer cell death without harming the non-tumorigenic cells. They also decreased MMP expression. Finally, early in vivo work was undertaken to determine how the collagen-nanoparticle gels are able to control cancer in

  16. ATTENUATION AND FLANKING TRANSMISSION IN LIGHTWEIGHT STRUCTURES

    DEFF Research Database (Denmark)

    Brunskog, Jonas; Lhomond, Alice; Ohlrich, Mogens

    2007-01-01

    In this paper the attenuation and flanking transmissions of impact noise in lightweight building structures is studied using a modal approach. The structural field is mainly analysed, putting the main attention to the parts being important in the modelling. The amount of attenuation produced...... by the periodically reinforcing beams used in lightweight building structures is analysed. The consequence of these factors in modelling flanking transmission is also discussed....

  17. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...... measurements of the much larger reflection parameters, hence commonly used nonprecision instruments can be used to determine the transmission errors with sufficient accuracy for the highest precision obtainable in standard laboratories....

  18. Light attenuation in estuarine mangrove lakes

    Science.gov (United States)

    Frankovich, Thomas A.; Rudnick, David T.; Fourqurean, James W.

    2017-01-01

    Submerged aquatic vegetation (SAV) cover has declined in brackish lakes in the southern Everglades characterized by low water transparencies, emphasizing the need to evaluate the suitability of the aquatic medium for SAV growth and to identify the light attenuating components that contribute most to light attenuation. Underwater attenuation of downwards irradiance of photosynthetically active radiation (PAR) was determined over a three year period at 42 sites in shallow (lakes in two sub-estuaries in the coastal Everglades, Florida USA. Turbidity, chromophoric dissolved organic matter (CDOM), and phytoplankton chlorophyll a (chl a) were measured concurrently and their respective contributions to the light attenuation rate were estimated. Light transmission to the benthos relative to literature estimates of minimum requirements for SAV growth indicated that the underwater light environment was often unsuitable for SAV. Light attenuation rates (n = 417) corrected for solar elevation angles ranged from 0.16 m-1 to 9.83 m-1 with a mean of 1.73 m-1. High concentrations of CDOM with high specific light absorption contributed the most to light attenuation followed by turbidity and chl a. CDOM alone sufficiently reduces light transmission beyond the estimated limits for SAV growth, making it difficult for ecosystem managers to increase SAV abundance by management activities. Light limitation of SAV in these areas may be a persistent feature because of their proximity to CDOM source materials from the surrounding mangrove swamp. Increasing freshwater flow into these areas may dilute CDOM concentrations and improve the salinity and light climate for SAV communities.

  19. Mechanisms of geometrical seismic attenuation

    Directory of Open Access Journals (Sweden)

    Igor B. Morozov

    2011-07-01

    Full Text Available In several recent reports, we have explained the frequency dependence of the apparent seismic quality-factor (Q observed in many studies according to the effects of geometrical attenuation, which was defined as the zero-frequency limit of the temporal attenuation coefficient. In particular, geometrical attenuation was found to be positive for most waves traveling within the lithosphere. Here, we present three theoretical models that illustrate the origin of this geometrical attenuation, and we investigate the causes of its preferential positive values. In addition, we discuss the physical basis and limitations of both the conventional and new attenuation models. For waves in media with slowly varying properties, geometrical attenuation is caused by variations in the wavefront curvature, which can be both positive (for defocusing and negative (for focusing. In media with velocity/density contrasts, incoherent reflectivity leads to geometrical-attenuation coefficients which are proportional to the mean squared reflectivity and are always positive. For «coherent» reflectivity, the geometrical attenuation is approximately zero, and the attenuation process can be described according to the concept of «scattering Q». However, the true meaning of this parameter is in describing the mean reflectivity within the medium, and not that of the traditional resonator quality factor known in mechanics. The general conclusion from these models is that non-zero and often positive levels of geometrical attenuation are common in realistic, heterogeneous media, both observationally and theoretically. When transformed into the conventional Q-factor form, this positive geometrical attenuation leads to Q values that quickly increase with frequency. These predictions show that the positive frequency-dependent Q observed in many datasets might represent artifacts of the transformations of the attenuation coefficients into Q.

  1. Maximum likelihood estimation of the attenuated ultrasound pulse

    DEFF Research Database (Denmark)

    Rasmussen, Klaus Bolding

    1994-01-01

    The attenuated ultrasound pulse is divided into two parts: a stationary basic pulse and a nonstationary attenuation pulse. A standard ARMA model is used for the basic pulse, and a nonstandard ARMA model is derived for the attenuation pulse. The maximum likelihood estimator of the attenuated...

  2. Ultraviolet, Optical, and Infrared Constraints on Models of Stellar Populations and Dust Attenuation

    CERN Document Server

    Johnson, Benjamin D; Seibert, Mark; Treyer, Marie; Martin, D Christopher; Barlow, Tom A; Forster, Karl; Friedman, Peter G; Morrissey, Patrick; Neff, Susan G; Small, Todd; Wyder, Ted K; Bianchi, Luciana; Donas, Jose; Heckman, Timothy M; Lee, Young-Wook; Madore, Barry F; Milliard, Bruno; Rich, R Michael; Szalay, A S; Welsh, Barry Y; Yi, Sukyoung K

    2007-01-01

    The color of galaxies is a fundamental property, easily measured, that constrains models of galaxies and their evolution. Dust attenuation and star formation history (SFH) are the dominant factors affecting the color of galaxies. Here we explore the empirical relation between SFH, attenuation, and color for a wide range of galaxies, including early types. These galaxies have been observed by GALEX, SDSS, and Spitzer, allowing the construction of measures of dust attenuation from the ratio of infrared (IR) to ultraviolet (UV) flux and measures of SFH from the strength of the 4000A break. The empirical relation between these three quantities is compared to models that separately predict the effects of dust and SFH on color. This comparison demonstrates the quantitative consistency of these simple models with the data and hints at the power of multiwavelength data for constraining these models. The UV color is a strong constraint; we find that a Milky Way extinction curve is disfavored, and that the UV emission ...

  3. Comparison of non-attenuation corrected and attenuation corrected myocardial perfusion SPE

    Directory of Open Access Journals (Sweden)

    Hasan Raza

    2016-09-01

    Conclusion: This study demonstrates that CT based attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging significantly improved the specificity of the RCA territory compared with non-attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging in both genders irrespective of BMI.

  4. Attenuation tomography in West Bohemia/Vogtland

    Science.gov (United States)

    Mousavi, Sima; Haberland, Christian; Bauer, Klaus; Hejrani, Babak; Korn, Michael

    2017-01-01

    We present a three-dimensional (3-D) P-wave attenuation (Qp) model for the geodynamically active swarm earthquake area of West Bohemia/Vogtland in the Czech/German border region. Path-averaged attenuation t* is calculated from amplitude spectra of time windows around the P-wave arrivals of local earthquakes. Average t/t* value or Qp for stations close to Nový Kostel are very low (focal zone (increases up to 500 within 80 km distance). The SIMUL2000 tomography scheme is used to invert the t* for P-wave attenuation perturbation. Analysis of resolution shows that our model is well-resolved in the vicinity of earthquake swarm hypocenters. The prominent features of the model are located around Nový Kostel focal zone and its northern vicinity. Beneath Nový Kostel a vertically stretched (down to depth of 11 km) and a highly attenuating body is observed. We believe that this is due to fracturing and high density of cracks inside the weak earthquake swarm zone in conjunction with presence of free gas/fluid. Further north of Nový Kostel two highly attenuating bodies are imaged which could represent fluid channels toward the surface. The eastern anomaly shows a good correlation with the fluid accumulation area which was suggested in 9HR seismic profile.

  5. Evolutionary history and attenuation of myxoma virus on two continents.

    Science.gov (United States)

    Kerr, Peter J; Ghedin, Elodie; DePasse, Jay V; Fitch, Adam; Cattadori, Isabella M; Hudson, Peter J; Tscharke, David C; Read, Andrew F; Holmes, Edward C

    2012-01-01

    The attenuation of myxoma virus (MYXV) following its introduction as a biological control into the European rabbit populations of Australia and Europe is the canonical study of the evolution of virulence. However, the evolutionary genetics of this profound change in host-pathogen relationship is unknown. We describe the genome-scale evolution of MYXV covering a range of virulence grades sampled over 49 years from the parallel Australian and European epidemics, including the high-virulence progenitor strains released in the early 1950s. MYXV evolved rapidly over the sampling period, exhibiting one of the highest nucleotide substitution rates ever reported for a double-stranded DNA virus, and indicative of a relatively high mutation rate and/or a continually changing selective environment. Our comparative sequence data reveal that changes in virulence involved multiple genes, likely losses of gene function due to insertion-deletion events, and no mutations common to specific virulence grades. Hence, despite the similarity in selection pressures there are multiple genetic routes to attain either highly virulent or attenuated phenotypes in MYXV, resulting in convergence for phenotype but not genotype.

  6. Evolutionary history and attenuation of myxoma virus on two continents.

    Directory of Open Access Journals (Sweden)

    Peter J Kerr

    Full Text Available The attenuation of myxoma virus (MYXV following its introduction as a biological control into the European rabbit populations of Australia and Europe is the canonical study of the evolution of virulence. However, the evolutionary genetics of this profound change in host-pathogen relationship is unknown. We describe the genome-scale evolution of MYXV covering a range of virulence grades sampled over 49 years from the parallel Australian and European epidemics, including the high-virulence progenitor strains released in the early 1950s. MYXV evolved rapidly over the sampling period, exhibiting one of the highest nucleotide substitution rates ever reported for a double-stranded DNA virus, and indicative of a relatively high mutation rate and/or a continually changing selective environment. Our comparative sequence data reveal that changes in virulence involved multiple genes, likely losses of gene function due to insertion-deletion events, and no mutations common to specific virulence grades. Hence, despite the similarity in selection pressures there are multiple genetic routes to attain either highly virulent or attenuated phenotypes in MYXV, resulting in convergence for phenotype but not genotype.

  7. Quantification of numerical aperture-dependence of the OCT attenuation coefficient (Conference Presentation)

    Science.gov (United States)

    Peinado, Liliana M.; Bloemen, Paul R.; Almasian, Mitra; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-03-01

    Despite the improvements in early cancer diagnosis, adequate diagnostic tools for early staging of bladder cancer tumors are lacking [1]. MEMS-probes based on optical coherence tomography (OCT) provide cross-sectional imaging with a high-spatial resolution at a high-imaging speed, improving visualization of cancerous tissue [2-3]. Additionally, studies show that the measurement of localized attenuation coefficient allows discrimination between healthy and cancerous tissue [4]. We have designed a new miniaturized MEMS-probe based on OCT that will optimize early diagnosis by improving functional visualization of suspicious lesions in bladder. During the optical design phase of the probe, we have studied the effect of the numerical aperture (NA) on the OCT signal attenuation. For this study, we have employed an InnerVision Santec OCT system with several numerical apertures (25mm, 40mm, 60mm, 100mm, 150mm and 200mm using achromatic lenses). The change in attenuation coefficient was studied using 15 dilutions of intralipid ranging between 6*10-5 volume% and 20 volume%. We obtained the attenuation coefficient from the OCT images at several fixed positions of the focuses using established OCT models (e.g. single scattering with known confocal point spread function (PSF) [5] and multiple scattering using the Extended Huygens Fresnel model [6]). As a result, a non-linear increase of the scattering coefficient as a function of intralipid concentration (due to dependent scattering) was obtained for all numerical apertures. For all intralipid samples, the measured attenuation coefficient decreased with a decrease in NA. Our results suggest a non-negligible influence of the NA on the measured attenuation coefficient. [1] Khochikar MV. Rationale for an early detection program for bladder cancer. Indian J Urol 2011 Apr-Jun; 27(2): 218-225. [2] Sun J and Xie H. Review Article MEMS-Based Endoscopic Optical Coherence Tomography. IJO 2011, Article ID 825629, 12 pages. doi:10

  8. 3D Attenuation Tomography of the Volcanic Island of Tenerife (Canary Islands)

    Science.gov (United States)

    Prudencio, J.; Ibáñez, J. M.; Del Pezzo, E.; Martí, J.; García-Yeguas, A.; De Siena, L.

    2015-09-01

    This paper shows a new multidisciplinary interpretation approach to the internal structure of Tenerife Island. The central core of this work is the determination of the three-dimensional attenuation structure of the region using P-waves and the coda normalization method. This study has been performed using 45,303 seismograms recorded at 85 seismic stations from an active experiment (air gun shots) conducted in January 2007. The interpretation of these new results is done combining the new images with previous studies performed in the area such as seismic velocity tomography, magnetic structure, magnetotelluric surveys or gravimetric models. Our new 3D images indicate the presence of seismic attenuation contrasts, with areas of high and low seismic attenuation patterns. High seismic attenuation zones are observed both in shallow and in deeper areas. The shallowest area of Las Cañadas caldera complex (1-3 km thick) is dominated by high attenuation behavior, and it is interpreted as the combined effect of sedimentary and volcanoclastic deposits, multifracture systems and the presence of shallow aquifers. At the same time, the deeper analyzed area, more than 8 km below sea level, is dominated by a high attenuation pattern, and it is interpreted as the consequence of the effect of high-temperature rocks in the crustal-mantle boundary. This interpretation is compatible and confirmed by previous models that indicate the presence of underplating magma in this region. On the contrary, some low attenuation bodies and structures have been identified at different depths. A deep low attenuation central body is interpreted as the original central structure associated with the early stage of Tenerife Island. At shallower depths, some low attenuation bodies are compatible with old intermediate magmatic chambers postulated by petrological studies. Finally, in the north of the island (La Orotava valley) we can interpret the low attenuation structure as the headwall of this valley

  9. Live attenuated vaccines for invasive Salmonella infections.

    Science.gov (United States)

    Tennant, Sharon M; Levine, Myron M

    2015-06-19

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines.

  10. Research on Nanosecond Pulse Corona Discharge Attenuation

    Institute of Scientific and Technical Information of China (English)

    HE Zheng-hao; XU Huai-li; BAI Jing; YU Fu-sheng; HU Feng; LI Jin

    2007-01-01

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control.Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted.The results show that the wave front decreases sharply during the corona discharge along the corona wire.The higher the amplitude of the applied pulse is,the more the amplitude of the wave front decreased.The wave attenuation responds in a lower corona discharge inversely.To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design.

  11. Postconditioning attenuates no-reflow in STEMI patients.

    Science.gov (United States)

    Mewton, Nathan; Thibault, Hélène; Roubille, François; Lairez, Olivier; Rioufol, Gilles; Sportouch, Catherine; Sanchez, Ingrid; Bergerot, Cyrille; Cung, Thien Tri; Finet, Gérard; Angoulvant, Denis; Revel, Didier; Bonnefoy-Cudraz, Eric; Elbaz, Meyer; Piot, Christophe; Sahraoui, Inesse; Croisille, Pierre; Ovize, Michel

    2013-11-01

    After acute myocardial infarction, the presence of no-reflow (or microvascular obstruction: MVO) has been associated with adverse left ventricular (LV) remodeling and worse clinical outcome. This study examined the effects of mechanical ischemic postconditioning on early and late MVO size in acute ST-elevation myocardial infarction (STEMI) patients. Fifty patients undergoing primary coronary angioplasty for a first STEMI with TIMI grade flow 0-1 and no collaterals were randomized to ischemic postconditioning (PC) (n = 25) or control (n = 25) groups. Ischemic PC consisted in the application of four consecutive cycles of a 1-min balloon occlusion, each followed by a 1-min deflation at the onset of reperfusion. Early (3 min post-contrast) and late (10 min post-contrast) MVO size were assessed by contrast-enhanced cardiac-MRI within 96 h after reperfusion. PC was associated with smaller early and late MVO size (3.9 ± 4.8 in PC versus 7.8 ± 6.6% of LV in controls for early MVO, P = 0.02; and 1.8 ± 3.1 in PC versus 4.1 ± 3.9% of LV in controls for late MVO; P = 0.01). This significant reduction was persistent after adjustment for thrombus aspiration, which neither had any significant effect on infarct size, nor on early or late MVO (P = NS for all). Attenuation of MVO was associated to infarct size reduction. Mechanical postconditioning significantly reduces MVO in patients with acute STEMI treated with primary angioplasty.

  12. Is there seismic attenuation in the mantle?

    Science.gov (United States)

    Ricard, Y.; Durand, S.; Montagner, J.-P.; Chambat, F.

    2014-02-01

    The small scale heterogeneity of the mantle is mostly due to the mixing of petrological heterogeneities by a smooth but chaotic convection and should consist in a laminated structure (marble cake) with a power spectrum S(k) varying as 1/k, where k is the wavenumber of the anomalies. This distribution of heterogeneities during convective stirring with negligible diffusion, called Batchelor regime is documented by fluid dynamic experiments and corresponds to what can be inferred from geochemistry and seismic tomography. This laminated structure imposes density, seismic velocity and potentially, anisotropic heterogeneities with similar 1/k spectra. A seismic wave of wavenumber k0 crossing such a medium is partly reflected by the heterogeneities and we show that the scattered energy is proportional to k0S(2k0). The reduction of energy for the propagating wave appears therefore equivalent to a quality factor 1/Q∝k0S(2k0). With the specific 1/k spectrum of the mantle, the resulting apparent attenuation should therefore be frequency independent. We show that the total contribution of 6-9% RMS density, velocity and anisotropy would explain the observed S and P attenuation of the mantle. Although these values are large, they are not unreasonable and we discuss how they depend on the range of frequencies over which the attenuation is explained. If such a level of heterogeneity were present, most of the attenuation of the Earth would be due to small scale scattering by laminations, not by intrinsic dissipation. Intrinsic dissipation must certainly exist but might correspond to a larger, yet unobserved Q. This provocative result would explain the very weak frequency dependence of the attenuation, and the fact that bulk attenuation seems negligible, two observations that have been difficult to explain for 50 years.

  13. Attenuation of endoplasmic reticulum stress by caffeine ameliorates hyperoxia-induced lung injury.

    Science.gov (United States)

    Teng, Ru-Jeng; Jing, Xigang; Michalkiewicz, Teresa; Afolayan, Adeleye J; Wu, Tzong-Jin; Konduri, Girija G

    2017-05-01

    Rodent pups exposed to hyperoxia develop lung changes similar to bronchopulmonary dysplasia (BPD) in extremely premature infants. Oxidative stress from hyperoxia can injure developing lungs through endoplasmic reticulum (ER) stress. Early caffeine treatment decreases the rate of BPD, but the mechanisms remain unclear. We hypothesized that caffeine attenuates hyperoxia-induced lung injury through its chemical chaperone property. Sprague-Dawley rat pups were raised either in 90 (hyperoxia) or 21% (normoxia) oxygen from postnatal day 1 (P1) to postnatal day 10 (P10) and then recovered in 21% oxygen until P21. Caffeine (20 mg/kg) or normal saline (control) was administered intraperitoneally daily starting from P2. Lungs were inflation-fixed for histology or snap-frozen for immunoblots. Blood caffeine levels were measured in treated pups at euthanasia and were found to be 18.4 ± 4.9 μg/ml. Hyperoxia impaired alveolar formation and increased ER stress markers and downstream effectors; caffeine treatment attenuated these changes at P10. Caffeine also attenuated the hyperoxia-induced activation of cyclooxygenase-2 and markers of apoptosis. In conclusion, hyperoxia-induced alveolar growth impairment is mediated, in part, by ER stress. Early caffeine treatment protects developing lungs from hyperoxia-induced injury by attenuating ER stress. Copyright © 2017 the American Physiological Society.

  14. Ultrasound transmission attenuation tomography using energy-scaled amplitude ratios

    Science.gov (United States)

    Chen, Ting; Shin, Junseob; Huang, Lianjie

    2016-04-01

    Ultrasound attenuation of breast tumors is related to their types and pathological states, and can be used to detect and characterize breast cancer. Particularly, ultrasound scattering attenuation can infer the margin properties of breast tumors. Ultrasound attenuation tomography quantitatively reconstructs the attenuation properties of the breast. Our synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays records both ultrasound reflection and transmission signals. We develop an ultrasound attenuation tomography method using ultrasound energy-scaled amplitude decays of ultrasound transmission signals and conduct ultrasound attenuation tomography using a known sound-speed model. We apply our ultrasound transmission attenuation tomography method to a breast phantom dataset, and compare the ultrasound attenuation tomography results with conventional beamforming ultrasound images obtained using reflection signals. We show that ultrasound transmission attenuation tomography complements beamforming images in identifying breast lesions.

  15. Microwave attenuation with composite of copper microwires

    Energy Technology Data Exchange (ETDEWEB)

    Gorriti, A.G.; Marin, P. [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Cortina, D. [Micromag S.L., Las Rozas, Madrid 28230 (Spain); Hernando, A., E-mail: antonio.hernando@adif.e [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Micromag S.L., Las Rozas, Madrid 28230 (Spain)

    2010-05-15

    It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

  16. Touch Attenuates Infants' Physiological Reactivity to Stress

    Science.gov (United States)

    Feldman, Ruth; Singer, Magi; Zagoory, Orna

    2010-01-01

    Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal…

  17. GPR measurements of attenuation in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmann, David, E-mail: djeisen@cnde.iastate.edu; Margetan, Frank J., E-mail: djeisen@cnde.iastate.edu; Pavel, Brittney, E-mail: djeisen@cnde.iastate.edu [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

    2015-03-31

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  18. Uterine doughnut by intrauterine device-induced photon attenuation on three-phase bone scintigraphy: artifact

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Myung Hee; Jeong, Hwan Jeong; Lim, Seok Tae [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2007-02-15

    A 44-year-old female underwent three-phase bone scintigraphy for an evaluation of right hip joint pain. The blood-flow and blood-pool images show a pelvic blush with a photopenic center (doughnut) prior to bladder filling. On the three hour delayed image, the pelvic uptake disappeared. The scintigraphic findings indicated the possibility of an early pregnancy. However, plain radiography demonstrated an intrauterine device. A uterine doughnut developed as a result of photon attenuation of intrauterine device.

  19. Sizes of mantle heteogeneities and seismic attenuation

    Science.gov (United States)

    Ricard, Y. R.; durand, S.; Chambat, F.; Montagner, J.

    2013-12-01

    The small scale heterogeneity of the mantle, being mostly due to the mixing of petrological heterogeneities by a smooth but chaotic convection should consist in a laminated structure (marble cake) with a power spectrum S(k) varying as 1/k, where k is the wavenumber of the anomalies. This distribution of heterogeneities during convective stirring with negligible diffusion, called Batchelor regime is documented by fluid dynamic experiments and corresponds to what can be inferred from geochemistry and seismic tomography. This laminated structure imposes density, seismic velocity and potentially, anisotropic heterogeneities with similar 1/k spectrums. We show that a seismic wave of wavenumber k_0 crossing such medium is partly reflected by the heterogeneities and the scattered energy has an energy found proportional to k_0 S(2k_0). The reduction of energy for the propagating wave appears therefore equivalent to a quality factor 1/Q proportional to k_0 S(2k_0). With the specific 1/k spectrum of the mantle, the resulting apparent attenuation should therefore be frequency independent. We show that the total contribution of 6-9% RMS density, velocity and anisotropy would explain the observed S and P attenuation of the mantle. Although these values are large there are not unreasonable and we discuss how they are likely overestimated. In this case, most of the attenuation of the Earth would be due to small scale scattering by laminations not by intrinsic dissipation. Intrinsic dissipation must certainly exists but might correspond to a larger, yet unobserved Q. This provocative result would explain the observed very weak frequency dependence of the attenuation, and the fact that bulk attenuation seems negligeable, two observations that have been difficult to explain for 50 years.

  20. Dosing schedule-dependent attenuation of dexamethasone-induced muscle atrophy in mice.

    Science.gov (United States)

    Nakao, Reiko; Yamamoto, Saori; Yasumoto, Yuki; Oishi, Katsutaka

    2014-05-01

    Many inflammatory and autoimmune diseases are treated using synthetic glucocorticoids. However, excessive glucocorticoid can often cause unpredictable effects including muscle atrophy. Endogenous glucocorticoid levels robustly fluctuate in a circadian manner and peak just before the onset of the active phase in both humans and nocturnal rodents. The present study determines whether muscle atrophy induced by exogenous glucocorticoid can be avoided by optimizing dosing times. We administered single daily doses of the glucocorticoid analog dexamethasone (Dex) to mice for 10 days at the times of day corresponding to peak (early night) or trough (early morning) endogenous glucocorticoid levels. Administration at the acrophase of endogenous glucocorticoids significantly attenuated Dex-induced wasting of the gastrocnemius (Ga) and tibialis anterior (TA) muscles that comprise mostly fast-twitch muscle fibers. Real-time RT-PCR revealed that the Dex-induced mRNA expression of genes encoding the atrophy-related ubiquitin ligases Muscle Atrophy F-box (Fbxo32, also known as MAFbx/Atrogin-1) and Muscle RING finger 1 (Trim63, also known as MuRF1) in the Ga and TA muscles was significantly attenuated by Dex when administered during the early night. Dex negligibly affected the weight of the soleus (So) muscle that mostly comprises slow-twitch muscle fibers, but significantly and similarly decreased the weight of the spleen at both dosing times. These results suggest that glucocorticoid-induced muscle atrophy can be attenuated by optimizing the dosing schedule.

  1. The Value of CT Attenuation in Distinguishing Atypical Adenomatous Hyperplasia from Adenocarcinoma in Situ

    Directory of Open Access Journals (Sweden)

    Binghu JIANG

    2013-11-01

    Full Text Available Background and objective: Advances in high-resolution computed tomography (CT scanning have increased the detection of small ground-glass opacity (GGO nodules and also allowed such images to be investigated in detail. However, it is difficult to differentiate atypical adenomatous hyperplasia (AAH from adenocarcinoma in situ (AIS with CT, even at follow-up, because they share many similar CT manifestations. While AAH is thought to be a precursor or even an early-stage lesion of lung adenocarcinoma, and the stepwise progression from AAH to AIS is thought to be reasonable. Therefore, the hypothesis that the attenuation of GGO is increased gradually from AAH to AIS is proposed. The aim of this study was to distinguish AAH from AIS with CT attenuation in patients with pure GGO nodules. 
Methods: Between January 2010 and December 2012, the CT findings in terms of the greatest diameter and mean CT attenuation (HU were reviewed and correlated with pathology in 56 patients with AAH (n=21 and non-mucinous AIS (n=38 by two independent observers. All the 59 lesions were pure GGO nodules with size of 2 cm or smaller. To determine variability of measuring CT attenuation, we calculated the 95% confidence interval (CI for the limits of agreement by using Bland-Altman analysis. Student t test was used to compare AAH and AIS in terms of diameter and CT attenuation. And receiver operating characteristic (ROC curve was used to determine the optimal cut-off value of mean CT attenuation for differentiating AAH from AIS and obtain the diagnostic value. Two-tailed P value of less than 0.05 was considered to be significant. 
Results: For the manually measured CT attenuation, the 95%CI for the limits of agreement was -40 HU, 50 HU for inter-observer variability. Although there was significant difference in nodule diameter between AAH and AIS (P=0.046, the overlap was considerable. The mean CT attenuation was (-718±53 HU (95%CI: -822, -604 for AAH, which was

  2. The Value of CT Attenuation in Distinguishing Atypical Adenomatous Hyperplasia from Adenocarcinoma in Situ

    Institute of Scientific and Technical Information of China (English)

    Binghu JIANG; Jichen WANG; Peng JIA; Meizhao LE

    2013-01-01

    Background and objective:Advances in high-resolution computed tomography (CT) scanning have increased the detection of small ground-glass opacity (GGO) nodules and also allowed such images to be investigated in detail. However, it is diffcult to differentiate atypical adenomatous hyperplasia (AAH) from adenocarcinoma in situ (AIS) with CT, even at follow-up, because they share many similar CT manifestations. While AAH is thought to be a precursor or even an early-stage lesion of lung adenocarcinoma, and the stepwise progression from AAH to AIS is thought to be reasonable. hTerefore, the hypothesis that the attenuation of GGO is increased gradually from AAH to AIS is proposed. hTe aim of this study was to distinguish AAH from AIS with CT attenuation in patients with pure GGO nodules. Methods:Between January 2010 and December 2012, the CT ifndings in terms of the greatest diameter and mean CT attenuation (HU) were reviewed and correlated with pathology in 56 patients with AAH (n=21) and non-mucinous AIS (n=38) by two independent observers. All the 59 lesions were pure GGO nodules with size of 2 cm or smaller. To determine variability of measuring CT attenuation, we calculated the 95%conifdence interval (CI) for the limits of agreement by using Bland-Altman analysis. Student t test was used to compare AAH and AIS in terms of diameter and CT attenuation. And receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value of mean CT attenuation for differentiating AAH from AIS and obtain the diagnostic value. Two-tailed P value of less than 0.05 was considered to be signiifcant. Results:For the manually measured CT attenuation, the 95%CI for the limits of agreement was-40 HU, 50 HU for inter-observer variability. Although there was significant difference in nodule diameter between AAH and AIS (P=0.046), the overlap was considerable. hTe mean CT attenuation was (-718±53) HU (95%CI:-822,-604) for AAH, which was signiifcantly smaller than

  3. Characterization and Monitoring of Natural Attenuation of Chlorinated Solvents in Ground Water: A Systems Approach

    Science.gov (United States)

    Cutshall, N. H.; Gilmore, T.; Looney, B. B.; Vangelas, K. M.; Adams, K. M.; Sink, C. H.

    2006-05-01

    the attenuation capacity. The mass balance approach is controlled by a combination of boundary conditions (e.g., water inputs and outputs), flow dynamics, and contaminant concentrations. As a result, long term monitoring might be improved while reducing costs by measuring fewer point concentrations and simultaneously adding large-scale measurements of boundary conditions, using weather data, remote sensing of evapotranspiration, stream-flow monitoring, etc. Because there are no specific regulatory drivers for performance-monitoring, regulators are not accustomed to participating in monitoring system design. A partnership with the Interstate Technology Regulatory Council (ITRC) has been formed to promote communication and develop advanced guidance for MNA. Early and continued communication among technology developers, end users, regulators and the public has been essential to this progress.

  4. Attenuation of seismic waves in Central Egypt

    Directory of Open Access Journals (Sweden)

    Mamdouh Abbas Morsy

    2013-06-01

    Full Text Available Attenuation of seismic waves in central Egypt had never been studied before. The results of the research on the seismic attenuation are based upon the information collected by the seismological network from 1998 to 2011. 855 earthquakes were selected from the Egyptian seismological catalog, with their epicenter distances between 15 and 150 km, their magnitudes ranging from 2 and 4.1 and focal depths reaching up to 30 km. The first systematic study of attenuation derived from the P-, S- and coda wave in the frequency range 1–24 Hz is presented. In the interpretation of the results both single and multiple scattering in a half space are considered. The single scattering model proposed by Sato (1977 was used. Two methods, the coda (Qc and the Multiple Lapse Time Window (MLTW method are used. The aim of this study is to validate these interpretations in the region and to try to identify the effects of attenuation due to intrinsic (Qi and scattering attenuation (Qsc. The mean Qc value calculated was Qc = (39 ± 1f1.0±0.009. The average Qc at 1.5 Hz is (53 ± 6 and Qc = (900 ± 195 at 24 Hz with Qo ranging between 23 and 107, where η ranging between 0.9 and 1.3. The quality factor (Q was estimated from spectra of P- and S-waves by applying a spectral ratio technique. The results show variations in Qp and QS as a function of frequency, according to the power law Q = 56η1.1. The seismic albedo is 0.7 at all stations and it mean that the earthquake activity is due to tectonic origin. The attenuation and frequency dependency for different paths and the correlation of the results with the geotectonic of the region are presented. The Qc values were calculated and correlated with the geology and tectonics of the area. The relatively low Qo and the high frequency dependency agree with the values of a region characterized by a low tectonic activity and vise versa.

  5. Early clerkships

    NARCIS (Netherlands)

    Kamalski, Digna M. A.; Ter Braak, Edith W. M. T.; Ten Cate, Olle Th. J.; Borleffs, Jan C. C.

    2007-01-01

    Background: Early clinical experience is being introduced in innovative, vertically integrated undergraduate medical curricula. While in many cases, this early clinical experience is limited to the presence of patients during lectures, in Utrecht students gain 'hands on' experience of daily clinical

  6. Attenuation of microwaves by poly-disperse small spheroid particles

    Science.gov (United States)

    Zhang, Peichang; Wang, Zhenhui

    1998-08-01

    Expressions for calculating the attenuation cross sections of poly-disperse, small spheroids, whose rotatory axes are in specific status, have been derived from a universal formula for calculating the attenuation cross section of a particle of arbitrary shape. Attenuation cross sections of liquid, ice, and spongy spheroidal droplets in different size and eccentricity at different wave lengths have been computed and analyzed.

  7. On the excess attenuation of sound in the atmosphere

    Science.gov (United States)

    Deloach, R.

    1975-01-01

    The attenuation suffered by an acoustic plane wave propagating from an elevated source to the ground, in excess of absorption losses, was studied. Reported discrepancies between attenuation measurements made in the field and theories which only account for absorption losses are discussed. It was concluded that the scattering of sound by turbulence results in a nonnegligible contribution to the total attenuation.

  8. Frequency Dependence of Attenuation Constant of Dielectric Materials

    Directory of Open Access Journals (Sweden)

    A. S. Zadgaonkar

    1975-01-01

    Full Text Available Different dielectric materials have been studied for frequency dependence of attenuation constant. The sensitive cathode ray oscillograph method has been used to evaluate to the dielectric constant and loss factor, and from these attenuation constants have been calculated. The temperature remaining constant, a regular increase has been observed in attenuation constant, at higher frequencies of electro-magnetic propagating wave.

  9. Carcinoma cervix with fat attenuating skull metastases

    Institute of Scientific and Technical Information of China (English)

    Anuradha Kapali; Atmakuri Sateesh Kumar; Mukunda Malathi; S D Shamsundar

    2016-01-01

    Skeletal metastasis in carcinoma cervix occurs in about 0.8-23% of cases. These lesions are usually radiographically lytic. Very few cases of metastases to the skull have been identiifed, about 5 cases to the best of our knowledge. We present a case of adenosquamous cell carcinoma of cervix with fat attenuating skull metastases in a 38-year-old lady that is not reported till date. The lesion was lytic, expansile and with negative attenuation of -15 to -30 Hounsifeld units corresponding to fat.Metastases must be included in the differentials of scalp lesions. A history of recent onset of swelling and associated lytic areas in calvarium on contrast enhanced computed tomography with multiplicity can give a clue to metastatic nature of disease.

  10. Attenuated partial internal reflection infrared spectroscopy.

    Science.gov (United States)

    Zhang, Zhenfeng; Ewing, George E

    2002-06-01

    A new method for the spectroscopic study of absorbing films is proposed. In contrast to the well-established methods that take advantage of the attenuation of total internal reflection (ATR) to obtain spectra, we intentionally arrange the optics to permit partial internal reflection from the sampling prism face. Attenuated partial internal reflection (APR) spectroscopy is introduced through theoretical calculations and experimental demonstrations. The calculated APR spectra in the infrared region were generated from the Fresnel and Airy equations. Experimentally, APR spectra of water films on a NaCl prism were obtained. APR is more sensitive than ATR, and can easily distinguish water films at the monolayer level (310 pm). The determination of film thickness from interference fringes in APR spectra is also illustrated. It is shown that APR can be used for film thickness measurements that can span 6 orders of magnitude. The limitations of APR are also discussed.

  11. Attenuated psychosis syndrome: benefits of explicit recognition

    Science.gov (United States)

    SCHIFFMAN, Jason; CARPENTER, William T

    2015-01-01

    Summary Given the unique characteristics of people who meet criteria for attenuated psychosis syndrome (APS) and the growing literature on the clinical benefits of providing services to individuals who meet these criteria, the APS diagnosis serves an important, and previously missing, role in psychiatry. The promotion of the APS diagnosis should help reduce the over-diagnosis and over-treatment of individuals with prodromal psychotic conditions and it should also encourage expanded training about attenuated psychosis among clinicians who primarily provide services to youth (a primary group who are diagnosed with APS). Only some of the individuals with APS subsequently develop psychosis, but all have existing clinical needs – regardless of subsequent conversion. The formal recognition of APS in DSM-5 will facilitate the research needed to identify and meet those needs. PMID:25852257

  12. Particle size characterization by ultrasonic attenuation spectra

    Institute of Scientific and Technical Information of China (English)

    Mingxu Su; Minghua Xue; Xiaoshu Cai; Zhitao Shang; Feng Xu

    2008-01-01

    This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonsa'ation inversion by the optimum regularization factor method is carded out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.

  13. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection.

  14. LCLS XTOD Attenuator System System Concept Report

    Energy Technology Data Exchange (ETDEWEB)

    Kishiyama, K; Roeben, M; Trent, J; Ryutov, D; Shen, S

    2006-04-12

    The attenuator system for the Linac Coherent Light Source (LCLS) X-ray Transport, Optics and Diagnostics (XTOD) system has been configured and analyzed by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The system layout, performance analyses and selection of the vacuum components are presented in this System Conceptual Review (SCR) report. Also included are the plans for prototype, procurement, mechanical integration, and the cost estimates.

  15. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  16. Novel Intriguing Strategies Attenuating to Sarcopenia

    Directory of Open Access Journals (Sweden)

    Kunihiro Sakuma

    2012-01-01

    Full Text Available Sarcopenia, the age-related loss of skeletal muscle mass, is characterized by a deterioration of muscle quantity and quality leading to a gradual slowing of movement, a decline in strength and power, increased risk of fall-related injury, and, often, frailty. Since sarcopenia is largely attributed to various molecular mediators affecting fiber size, mitochondrial homeostasis, and apoptosis, the mechanisms responsible for these deleterious changes present numerous therapeutic targets for drug discovery. Resistance training combined with amino acid-containing supplements is often utilized to prevent age-related muscle wasting and weakness. In this review, we summarize more recent therapeutic strategies (myostatin or proteasome inhibition, supplementation with eicosapentaenoic acid (EPA or ursolic acid, etc. for counteracting sarcopenia. Myostatin inhibitor is the most advanced research with a Phase I/II trial in muscular dystrophy but does not try the possibility for attenuating sarcopenia. EPA and ursolic acid seem to be effective as therapeutic agents, because they attenuate the degenerative symptoms of muscular dystrophy and cachexic muscle. The activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α in skeletal muscle by exercise and/or unknown supplementation would be an intriguing approach to attenuating sarcopenia. In contrast, muscle loss with age may not be influenced positively by treatment with a proteasome inhibitor or antioxidant.

  17. Simvastatin attenuates bleomycin-induced pulmonary fibrosis in mice

    Institute of Scientific and Technical Information of China (English)

    OU Xue-mei; FENG Yu-lin; WEN Fu-qiang; HUANG Xiang-yang; XIAO Jun; WANG Ke; WANG Tao

    2008-01-01

    Background Bleomycin-induced fibrosis is extensively used to model aspects of the pathogenesis of interstitial pulmonary fibrosis. This study aimed to determine the benefic effects and mechanisms of simvastatin on bleomycin-induced pulmonary fibrosis in mice.Methods Bleomycin-induced pulmonary fibrosis mice were administered with simvastatin in different doses for 28 days.We measured inflammatory response, fibrogenic cytokines and profibrogenic markers in both bleomycin-stimulated and control lungs, and correlated these parameters with pulmonary fibrosis.Results Simvastatin attenuated the histopathological change of bleomycin-induced pulmonary fibrosis and prevented the increase of lung hydroxyproline content and collagen (Ⅰand Ⅲ) mRNA expression induced by bleomycin. Moreover,simvastatin down-regulated the increased expression of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) induced by bleomycin at both gene and protein levels. Simultaneously, the accumulation of neutrophils and lymphocytes and the increased production of tumor necrosis factor-(] (TNF-a) in bronchial alveolar lavage fluid were inhibited by simvastatin in early inflammatory phase after bleomycin infusion. The higher dose of simvastatin was associated with a more significant reduction in these inflammatory and fibrotic parameters. Furthermore,the inactivation of p38, RhoA and Smad2/3 signaling pathways was observed during simvastatin administration.Conclusions Simvastatin attenuated bleomycin-induced pulmonary fibrosis, as indicated by decreases in Ashcroft score and lung collagen accumulation. The inhibitory effect of simvastatin on the progression of pulmonary fibrosis may be demonstrated by reducing inflammatory response and production of TGF-βI and CTGF. These findings indicate that simvastatin may be used in the treatment of pulmonary fibrosis.

  18. Seismic Attenuation Inversion with t* Using tstarTomog.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2014-09-01

    Seismic attenuation is defined as the loss of the seismic wave amplitude as the wave propagates excluding losses strictly due to geometric spreading. Information gleaned from seismic waves can be utilized to solve for the attenuation properties of the earth. One method of solving for earth attenuation properties is called t*. This report will start by introducing the basic theory behind t* and delve into inverse theory as it pertains to how the algorithm called tstarTomog inverts for attenuation properties using t* observations. This report also describes how to use the tstarTomog package to go from observed data to a 3-D model of attenuation structure in the earth.

  19. Intensity attenuation in the Pannonian Basin

    Science.gov (United States)

    Győri, Erzsébet; Gráczer, Zoltán; Szanyi, Gyöngyvér

    2015-04-01

    Ground motion prediction equations play a key role in seismic hazard assessment. Earthquake hazard has to be expressed in macroseismic intensities in case of seismic risk estimations where a direct relation to the damage associated with ground shaking is needed. It can be also necessary for shake map generation where the map is used for prompt notification to the public, disaster management officers and insurance companies. Although only few instrumental strong motion data are recorded in the Pannonian Basin, there are numerous historical reports of past earthquakes since the 1763 Komárom earthquake. Knowing the intensity attenuation and comparing them with relations of other areas - where instrumental strong motion data also exist - can help us to choose from the existing instrumental ground motion prediction equations. The aim of this work is to determine an intensity attenuation formula for the inner part of the Pannonian Basin, which can be further used to find an adaptable ground motion prediction equation for the area. The crust below the Pannonian Basin is thin and warm and it is overlain by thick sediments. Thus the attenuation of seismic waves here is different from the attenuation in the Alp-Carpathian mountain belt. Therefore we have collected intensity data only from the inner part of the Pannonian Basin and defined the boundaries of the studied area by the crust thickness of 30 km (Windhoffer et al., 2005). 90 earthquakes from 1763 until 2014 have sufficient number of macroseismic data. Magnitude of the events varies from 3.0 to 6.6. We have used individual intensity points to eliminate the subjectivity of drawing isoseismals, the number of available intensity data is more than 3000. Careful quality control has been made on the dataset. The different types of magnitudes of the used earthquake catalogue have been converted to local and momentum magnitudes using relations determined for the Pannonian Basin. We applied the attenuation formula by Sorensen

  20. Early literacy

    DEFF Research Database (Denmark)

    Jensen, Anders Skriver

    2012-01-01

    This paper discusses findings from the Danish contribution to the EASE project, a European research project running from 2008 to 2010 on early literacy in relation to the transition from childcare to school. It explores a holistic, inclusive approach to early literacy that resists a narrow...... and schools. The paper also draws on Gee’s (2001, 2003, 2004, 2008) sociocultural approach to literacy, and Honneth’s (2003, 2006) concept of recognition. Emphasizing participation and recognition as key elements, it claims that stakeholders in early liter- acy must pay attention to how diverse early literacy...... opportunities empower children, especially when these opportunities are employed in a project-based learning environ- ment in which each child is able to contribute to the shared literacy events....

  1. Determination of the attenuation map in emission tomography

    CERN Document Server

    Zaidi, H

    2002-01-01

    Reliable attenuation correction methods for quantitative emission computed tomography (ECT) require accurate delineation of the body contour and often necessitate knowledge of internal anatomical structure. Two broad classes of methods have been used to calculate the attenuation map referred to as "transmissionless" and transmission-based attenuation correction techniques. While calculated attenuation correction belonging to the first class of methods is appropriate for brain studies, more adequate methods must be performed in clinical applications where the attenuation coefficient distribution is not known a priori, and for areas of inhomogeneous attenuation such as the chest. Measured attenuation correction overcomes this problem and utilizes different approaches to determine this map including transmission scanning, segmented magnetic resonance images or appropriately scaled X-ray CT scans acquired either independently on separate or simultaneously on multimodality imaging systems. Combination of data acqu...

  2. Single Site Strong-Motion Attenuation Relationship

    Science.gov (United States)

    Sung, C.; Lee, C.

    2009-12-01

    The standard deviation of the logarithmic residuals in ground-motion prediction may directly influence the result of probabilistic seismic hazard analysis, especially in low probability. Therefore, “how to reduce the σ?” becomes an important issue in recent years. In most modern empirical ground motion studies, the total variability was separated into inter-event and intra-event components to distinction between epistemic uncertainty and aleatory uncertainty. Another approach is gaining control over the value of σ is to investigate in more detail the behavior of the individual components of variability with a single event or a single station (e.g., Niazi and Bozorgnia 1991; Ordaz and Reyes 1999; Jain et al. 2000; Atkinson 2006; Morikawa et al (2008)). In this study, we use the large data set available from the Taiwan Strong Motion Instrumentation Program (TSMIP) and select stations which recorded more than 700 strong-motion records (six stations). The ground motion attenuation is modified based on Campbell form which includes source term, distance term and site term Vs30. It is worth noting that a single site strong motion attenuation model does not include the site term, because the site is fixed at a station. Finally, we use hemisphere projection to show the path effect of residual in this study and compare the standard deviation for a single station (σi) and total stations (σT). We find that the single-station standard deviation is 20% smaller than the total standard deviation in this study and the result is better than Atkinson (2006). In the future work, a single source-region where occurred more than 5 earthquakes which triggered more than 50 stations will be selected for single source-region attenuation study.

  3. Measuring the attenuation length in liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Hellgartner, Dominikus; Oberauer, Lothar; Prummer, Sabrina; Sawatzki, Julia; Zimmer, Vincenz [Technische Universitaet Muenchen, Physik Departement E15, James Franck Strasse, 85748 Garching (Germany); Ulrich, Andreas [Technische Universitaet Muenchen, Physik Departement E12, James Franck Strasse, 85748 Garching (Germany)

    2015-07-01

    The next generation of liquid scintillator detectors like the proposed LENA detector or the planned JUNO detector will feature diameters of order 30 m. Due to this vast size, the optical quality of the scintillator is of crucial importance. To determine the attenuation length of liquid scintillators, an experiment with a 5 m long measurement section was set-up in the underground laboratory in Garching. The current set-up of the experiment is presented along with a discussion of the results of the first measurements. Additionally, there is an outlook towards possible upgrades of the experiment in the future.

  4. DMATIS: Dark Matter ATtenuation Importance Sampling

    Science.gov (United States)

    Mahdawi, Mohammad Shafi; Farrar, Glennys R.

    2017-05-01

    DMATIS (Dark Matter ATtenuation Importance Sampling) calculates the trajectories of DM particles that propagate in the Earth's crust and the lead shield to reach the DAMIC detector using an importance sampling Monte-Carlo simulation. A detailed Monte-Carlo simulation avoids the deficiencies of the SGED/KS method that uses a mean energy loss description to calculate the lower bound on the DM-proton cross section. The code implementing the importance sampling technique makes the brute-force Monte-Carlo simulation of moderately strongly interacting DM with nucleons computationally feasible. DMATIS is written in Python 3 and MATHEMATICA.

  5. Tick passage results in enhanced attenuation of Babesia bovis.

    Science.gov (United States)

    Sondgeroth, Kerry S; McElwain, Terry F; Ueti, Massaro W; Scoles, Glen A; Reif, Kathryn E; Lau, Audrey O T

    2014-10-01

    Serial blood passage of virulent Babesia bovis in splenectomized cattle results in attenuated derivatives that do not cause neurologic disease. Tick transmissibility can be lost with attenuation, but when retained, attenuated B. bovis can revert to virulence following tick passage. This study provides data showing that tick passage of the partially attenuated B. bovis T2Bo derivative strain further decreased virulence compared with intravenous inoculation of the same strain in infected animals. Ticks that acquired virulent or attenuated parasites by feeding on infected cattle were transmission fed on naive, splenectomized animals. While there was no significant difference between groups in the number of parasites in the midgut, hemolymph, or eggs of replete female ticks after acquisition feeding, animals infected with the attenuated parasites after tick transmission showed no clinical signs of babesiosis, unlike those receiving intravenous challenge with the same attenuated strain prior to tick passage. Additionally, there were significantly fewer parasites in blood and tissues of animals infected with tick-passaged attenuated parasites. Sequencing analysis of select B. bovis genes before and after tick passage showed significant differences in parasite genotypes in both peripheral blood and cerebral samples. These results provide evidence that not only is tick transmissibility retained by the attenuated T2Bo strain, but also it results in enhanced attenuation and is accompanied by expansion of parasite subpopulations during tick passage that may be associated with the change in disease phenotype. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  6. Azithromycin attenuates airway inflammation in a mouse model of viral bronchiolitis

    Directory of Open Access Journals (Sweden)

    Brody Steven L

    2010-06-01

    Full Text Available Abstract Background Viral bronchiolitis is the leading cause of hospitalization in young infants. It is associated with the development of childhood asthma and contributes to morbidity and mortality in the elderly. Currently no therapies effectively attenuate inflammation during the acute viral infection, or prevent the risk of post-viral asthma. We hypothesized that early treatment of a paramyxoviral bronchiolitis with azithromycin would attenuate acute and chronic airway inflammation. Methods Mice were inoculated with parainfluenza type 1, Sendai Virus (SeV, and treated daily with PBS or azithromycin for 7 days post-inoculation. On day 8 and 21 we assessed airway inflammation in lung tissue, and quantified immune cells and inflammatory mediators in bronchoalveolar lavage (BAL. Results Compared to treatment with PBS, azithromycin significantly attenuated post-viral weight loss. During the peak of acute inflammation (day 8, azithromycin decreased total leukocyte accumulation in the lung tissue and BAL, with the largest fold-reduction in BAL neutrophils. This decreased inflammation was independent of changes in viral load. Azithromycin significantly attenuated the concentration of BAL inflammatory mediators and enhanced resolution of chronic airway inflammation evident by decreased BAL inflammatory mediators on day 21. Conclusions In this mouse model of paramyxoviral bronchiolitis, azithromycin attenuated acute and chronic airway inflammation. These findings demonstrate anti-inflammatory effects of azithromycin that are not related to anti-viral activity. Our findings support the rationale for future prospective randomized clinical trials that will evaluate the effects of macrolides on acute viral bronchiolitis and their long-term consequences.

  7. Ultra-low acoustoelectric attenuation in graphene

    Science.gov (United States)

    Tang, Chiu-Chun; Chen, Yung-Fu; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2017-03-01

    We investigate the acoustoelectric properties of graphene and extract its acoustoelectric attenuation Γ as a function of the carrier density n, tuned via ionic liquid gating. Acoustoelectric effects in graphene are induced by launching surface acoustic waves (SAWs) on a piezoelectric LiNbO3 substrate. We measure the acoustoelectric current Iae through graphene and extract the SAW attenuation factor Γ as a function of n. The magnitude of Iae increases with decreasing n when the n is far from the charge neutral point (CNP). When n is tuned across the CNP, Iae first exhibits a local maximum, vanishes at the CNP, and then changes sign in accordance with the associated change in the carrier polarity. By contrast, Γ monotonically increases with decreasing n and reaches a maximum at the CNP. The extracted values of Γ, calibrated at the central frequency of 189 MHz, vary from ˜0.4 m-1 to 6.8 m-1, much smaller than the values for known two-dimensional systems. Data analysis suggests that the evolution of Iae and Γ with n manifests the electronic states of graphene. Our experimental findings provide insightful information for developing innovative graphene-based devices.

  8. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  9. Perchlorate natural attenuation in a riparian zone.

    Science.gov (United States)

    Borden, Robert C; Knox, Sheri L; Lieberman, M Tony; Ogles, Dora

    2014-01-01

    Multiple lines of evidence were used to document the natural attenuation of perchlorate in a shallow alluvial aquifer. In the upgradient, aerobic portion of the aquifer, perchlorate did not biodegrade. However, natural flushing by groundwater flow is reducing perchlorate concentrations in the aquifer over time. Perchlorate concentrations in the source area are expected to meet cleanup criteria in 11 to 27 years without active remedial measures. At the distal end of the plume, perchlorate is rapidly degraded as it migrates upward through organic rich littoral zone sediments. Apparent first-order degradation rates in groundwater were about 0.20 d(-1) and are consistent with laboratory macrocosm rates (0.12 d(-1)). qPCR results show a distinct region of the littoral zone where perchlorate degraders are elevated. The Eh within this zone varies from +0.1 to +0.3 V indicating perchlorate degraders can thrive in moderately oxidizing conditions. The study has shown that (i) there was no apparent perchlorate biodegradation in aerobic aquifer; (ii) perchlorate declines over time in aerobic aquifer due to flushing; (iii) there was a rapid perchlorate attenuation in organic rich littoral zone; and, (iv) qPCR results show large increases in perchlorate degraders in the littoral zone.

  10. Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  11. Towards a Global Upper Mantle Attenuation Model

    Science.gov (United States)

    Karaoglu, Haydar; Romanowicz, Barbara

    2015-04-01

    Global anelastic tomography is crucial for addressing the nature of heterogeneity in the Earth's interior. The intrinsic attenuation manifests itself through dispersion and amplitude decay. These are contaminated by elastic effects such as (de)focusing and scattering. Therefore, mapping anelasticity accurately requires separation of elastic effects from the anelastic ones. To achieve this, a possible approach is to try and first predict elastic effects through the computation of seismic waveforms in a high resolution 3D elastic model, which can now be achieved accurately using numerical wavefield computations. Building upon the recent construction of such a whole mantle elastic and radially anisotropic shear velocity model (SEMUCB_WM1, French and Romanowicz, 2014), which will be used as starting model, our goal is to develop a higher resolution 3D attenuation model of the upper mantle based on full waveform inversion. As in the development of SEMUCB_WM1, forward modeling will be performed using the spectral element method, while the inverse problem will be treated approximately, using normal mode asymptotics. Both fundamental and overtone time domain long period waveforms (T>60s) will be used from a dataset of over 200 events observed at several hundred stations globally. Here we present preliminary results of synthetic tests, exploring different iterative inversion strategies.

  12. Live attenuated influenza vaccine--a review.

    Science.gov (United States)

    Gasparini, R; Amicizia, D; Lai, P L; Panatto, D

    2011-09-01

    Owing to the variability of influenza viruses, vaccine composition needs to be up-dated annually. As many variables can influence their efficacy, vaccines are still considered "sub-optimal". Many studies have been carried out in recent years to improve vaccines. In particular, researchers and vaccine-producing corporations have focused on developing a live vaccine. Among the candidate vaccines, the strain developed by Maassab has recently been licensed in the USA and Europe, after extensive investigation. This vaccine is safe and well tolerated, and has shown very good genetic stability. Although vaccine recipients are able to spread the virus, transmission to close contacts is practically non-existent. Studies on cold-adapted attenuated influenza vaccines have demonstrated that such vaccines are effective, and sometimes more effective than inactivated influenza vaccines. Cold-adapted attenuated influenza vaccines therefore appear to be an important weapon against influenza. However, a more widespread use of these vaccines is to be recommended, especially in children, as the more acceptable way of administration can favour parental compliance.

  13. Attenuation correction without transmission scan for the MAMMI breast PET

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, A., E-mail: soriano@ific.uv.es [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Edificio Institutos de Paterna. Catedratico Jose Beltran, 2. E-46980 Paterna (Spain); Gonzalez, A. [ONCOVISION (GEM-Imaging group), Valencia (Spain); Orero, A.; Moliner, L.; Carles, M.; Sanchez, F.; Benlloch, J.M. [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Edificio Institutos de Paterna. Catedratico Jose Beltran, 2. E-46980 Paterna (Spain); Correcher, C.; Carrilero, V.; Seimetz, M. [ONCOVISION (GEM-Imaging group), Valencia (Spain)

    2011-08-21

    Whole-body Positron Emission Tomography (PET) scanners are required in order to span large Fields of View (FOV). Therefore, reaching the sensitivity and spatial resolution required for early stage breast tumor detection is not straightforward. MAMMI is a dedicated breast PET scanner with a ring geometry designed to provide PET images with a spatial resolution as high as 1.5 mm, being able to detect small breast tumors (<1cm). The patient lays down in prone position during the scan, thus making possible to image the whole breast, up to regions close to the base of the pectoral without the requirement of breast compression. Attenuation correction (AC) for PET data improves the image quality and the quantitative accuracy of radioactivity distribution determination. In dedicated, high resolution breast cancer scanners, this correction would enhance the proper diagnosis in early disease stages. In whole-body PET scanners, AC is usually taken into account with the use of transmission scans, either by external radioactive rod sources or by Computed Tomography (CT). This considerably increases the radiation dose administered to the patient and time needed for the exploration. In this work we propose a method for breast shape identification by means of PET image segmentation. The breast shape identification will be used for the determination of the AC. For the case of a specific breast PET scanner the procedure we propose should provide AC similar to that obtained by transmission scans as we take advantage of the breast anatomical simplicity. Experimental validation of the proposed approach with a dedicated breast PET prototype is also presented. The main advantage of this method is an important dose reduction since the transmission scan is not required.

  14. Postconditioning attenuates acute intestinal ischemia–reperfusion injury

    Directory of Open Access Journals (Sweden)

    Ilker Sengul

    2013-03-01

    Full Text Available The aim of this study was to test the hypothesis that postconditioning (POC would reduce the detrimental effects of the acute intestinal ischemia–reperfusion (I/R compared to those of the abrupt onset of reperfusion. POC has a protective effect on intestinal I/R injury by inhibiting events in the early minutes of reperfusion in rats. Twenty-four Wistar–Albino rats were subjected to the occlusion of superior mesenteric artery for 30 minutes, then reperfused for 120 minutes, and randomized to the four different modalities of POC: (1 control (no intervention; (2 POC-3 (three cycles of 10 seconds of reperfusion–reocclusion, 1 minute total intervention; (3 POC-6 (six cycles of 10 seconds of reperfusion–reocclusion, 2 minutes total intervention; and (4 sham operation (laparotomy only. The arterial blood samples [0.3 mL total creatine kinase (CK and 0.6 mL malondialdehyde (MDA] and the intestinal mucosal MDA were collected from each after reperfusion. POC, especially POC-6, was effective in attenuating postischemic pathology by decreasing the intestinal tissue MDA levels, serum total CK activity, inflammation, and total histopathological injury scores. POC exerted a protective effect on the intestinal mucosa by reducing the mesenteric oxidant generation, lipid peroxidation, and neutrophil accumulation. The six-cycle algorithm demonstrated the best protection.

  15. Intermedin attenuates LPS-induced inflammation in the rat testis.

    Directory of Open Access Journals (Sweden)

    Lei Li

    Full Text Available First reported as a vasoactive peptide in the cardiovascular system, intermedin (IMD, also known as adrenomedullin 2 (ADM2, is a hormone with multiple potent roles, including its antioxidant action on the pulmonary, central nervous, cardiovascular and renal systems. Though IMD may play certain roles in trophoblast cell invasion, early embryonic development and cumulus cell-oocyte interaction, the role of IMD in the male reproductive system has yet to be investigated. This paper reports our findings on the gene expression of IMD, its receptor components and its protein localization in the testes. In a rat model, bacterial lippolysaccharide (LPS induced atypical orchitis, and LPS treatment upregulated the expression of IMD and one of its receptor component proteins, i.e. receptor activity modifying protein 2 (RAMP2. IMD decreased both plasma and testicular levels of reactive oxygen species (ROS production, attenuated the increase in the gene expression of the proinflammatory cytokines tumor necrosis factor alpha (TNFα, interleukin 6 (IL6 and interleukin 1 beta (IL1β, rescued spermatogenesis, and prevented the decrease in plasma testosterone levels caused by LPS. The restorative effect of IMD on steroidogenesis was also observed in hydrogen peroxide-treated rat primary Leydig cells culture. Our results indicate IMD plays an important protective role in spermatogenesis and steroidogenesis, suggesting therapeutic potential for IMD in pathological conditions such as orchitis.

  16. Ovariectomy attenuates dendritic growth in hormone-sensitive spinal motoneurons.

    Science.gov (United States)

    Hebbeler, S L; Verhovshek, T; Sengelaub, D R

    2001-09-15

    The lumbar spinal cord of rats contains the sexually dimorphic, steroid-sensitive spinal nucleus of the bulbocavernosus (SNB). Dendritic development of SNB motoneurons in male rats is biphasic, initially showing exuberant growth through 4 weeks of age followed by a retraction to mature lengths by 7 weeks of age. The initial growth is steroid dependent, attenuated by castration or aromatase inhibition, and supported by hormone replacement. Dendritic retraction is also steroid sensitive and can be prevented by testosterone treatment, but is unaffected by aromatase inhibition. Together, these results suggest a role for estrogens during the initial growth phase of SNB development. In this study, we tested whether ovarian hormones could support SNB somal and dendritic development. Motoneuron morphology was assessed in normal males and in females perinatally masculinized with dihydrotestosterone and then either ovariectomized or left intact. SNB motoneurons were retrogradely labeled with cholera toxin-HRP at 4 or 7 weeks of age and reconstructed in three dimensions. Initial growth of SNB dendrites was reduced after ovariectomy in masculinized females. However, no differences in dendritic length were seen at 7 weeks of age between intact and ovariectomized masculinized females, and lengths in both groups were significantly lower than those of normal males. Together with previous findings, these results suggest that estrogens are involved in the early growth of SNB dendrites, but not in their subsequent retraction.

  17. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi

    2016-09-06

    We present an acoustic eikonal equation governing the complex-valued travel time of P-waves in attenuating, transversely isotropic media with a vertical symmetry axis (VTI). This equation is based on the assumption that the Pwave complex-valued travel time is independent of the Swave velocity parameter v in Thomsen\\'s notation and the attenuation coefficient A in the Thomsen-type notation for attenuating VTI media. We combine perturbation theory and Shanks transform to develop practical approximations to the attenuating acoustic eikonal equation, capable of admitting analytical description of the attenuation in homogeneous media. For a horizontal, attenuating VTI layer, we also derive non-hyperbolic approximations for the real and imaginary parts of the complex-valued reflection travel time.

  18. Attenuation of an original US porcine epidemic diarrhea virus strain PC22A via serial cell culture passage.

    Science.gov (United States)

    Lin, Chun-Ming; Hou, Yixuan; Marthaler, Douglas G; Gao, Xiang; Liu, Xinsheng; Zheng, Lanlan; Saif, Linda J; Wang, Qiuhong

    2017-03-01

    Although porcine epidemic diarrhea (PED) has caused huge economic losses in the pork industry worldwide, an effective live, attenuated vaccine is lacking. In this study, an original US, highly virulent PED virus (PEDV) strain PC22A was serially passaged in Vero CCL81 and Vero BI cells. The virus growth kinetics in cell culture, virulence in neonatal pigs and the whole genomic sequences of selected passages were examined. Increased virus titers and sizes of syncytia were observed at the 65th passage level (P65) and P120, respectively. Based on the severity of clinical signs, histopathological lesions and the distribution of PEDV antigens in the gut, the virulence of P100 and above, but not P95C13 (CCL81), was markedly reduced in 4-day-old, caesarian-derived, colostrum-deprived piglets. Subsequently, the attenuation of P120 and P160 was confirmed in 4-day-old, conventional suckling piglets. Compared with P120, P160 replicated less efficiently in the intestine of pigs and induced a lower rate of protection after challenge. Sequence analysis revealed that the virulent viruses [P3 and P95C13 (CCL81)] had one, one, sixteen (including an early termination of nine amino acids) and two amino acid differences in non-structure protein 1 (nsp1), nsp4, spike and membrane proteins, respectively, from the fully attenuated P160. However, the overall pattern of attenuation-related genetic changes in PC22A differed from those of the other four pairs of PEDV wild type strains and their attenuated derivatives. These results suggest that PEDV attenuation can occur through multiple molecular mechanisms. The knowledge provides insights into potential molecular mechanisms of PEDV attenuation. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. A wideband IM3 cancellation technique for CMOS attenuators

    NARCIS (Netherlands)

    Cheng, W.; Oude Alink, M.S.; Annema, A.J.; Wienk, G.J.M.; Nauta, B.

    2012-01-01

    A highly linear P attenuator system using a wideband IM3 cancellation technique is presented that provides 4 discrete attenuation levels with 6dB spacing for DC-5GHz. For the whole band, S11<-14dB, attenuation flatness<1.6dB, +10dBm input P1dB and +26dBm IIP3 are achieved. For the TV band (0.1Gz-1.2

  20. Sulfasalazine attenuates ACL transection and medial menisectomy-induced cartilage destruction by inhibition of cystine/glutamate antiporter.

    Science.gov (United States)

    Tsai, Wei-Yuan; Tsai, Ru-Yin; Liu, Chih-Chung; Wu, Jia-Lin; Wong, Chih-Shung

    2016-04-01

    We had previously demonstrated that excitatory amino acid glutamate plays a role in the progression and severity of knee osteoarthritis (OA), and early hyaluronic acid injection attenuates the OA progression by attenuation of knee joint glutamate level, which was also related to the cystine/glutamate antiporter system X (system XC-) expression. System XC- uptakes cystine into chondrocytes for glutathione (GSH) synthesis, but the role of system XC- in OA is rarely addressed. Sulfasalazine (SSZ) is a system XC- inhibitor; SSZ was applied intra-articularly to study the function of system XC- in the development of OA in rats subjected to anterior cruciate ligament transection and medial meniscectomy (ACLT + MMx). Moerover, the system XC- activator N-acetylcysteine (NAC) was also applied to verify the role of system XC-. The intra-articular injection of SSZ significantly attenuated knee swelling and cartilage destruction in the knees of ACLT + MMx rats and this effect was blocked by NAC. The results showed that inhibition of system XC- function can attenuate ACLT + MMx-induced cartilage destruction. In the present study, system XC- inhibitor SSZ was shown to reduce glutamate content in synovial fluid and GSH in chondrocytes. It was also showed SSZ could attenuate ACLT + MMx-induced cartilage destruction, and treatment of NAC reversed the protective effect of SSZ.

  1. Calibrating surface weather observations to atmospheric attenuation measurements

    Science.gov (United States)

    Sanii, Babak

    2001-06-01

    A correlation between near-IR atmospheric attenuation measurements made by the Atmospheric Visibility Monitor (AVM) at the Table Mountain Facility and airport surface weather observations at Edwards Air Force Base has been performed. High correlations (over 0.93) exist between the Edwards observed sky cover and the average AVM measured attenuations over the course of the 10 months analyzed. The statistical relationship between the data-sets allows the determination of coarse attenuation statistics from the surface observations, suggesting that such statistics may be extrapolated from any surface weather observation site. Furthermore, a superior technique for converting AVM images to attenuation values by way of MODTRAN predictions has been demonstrated.

  2. Attenuation characteristics of ground motions in northern China

    Institute of Scientific and Technical Information of China (English)

    黄玉龙; 赵兴权; 罗奇峰

    2002-01-01

    Four recently developed attenuation models are calibrated by using a very limited amount of strong motion data recorded in China. The research shows that the attenuation characteristics of the earthquake shaking in northern China are similar to those in the western US. The supporting evidence includes Q factors, preliminary results of kappa values, stress drop,shear wave velocity profile in the shallow earth crust, areas enclosed by the isoseismals of Modified Mercalli Intensity V. From these comparisons of different attenuation models, it is recommended that the Crouse and McGuire spectral attenuation model could possibly be used for northern China.

  3. An Approximate Method for the Acoustic Attenuating VTI Eikonal Equation

    KAUST Repository

    Hao, Q.

    2017-05-26

    We present an approximate method to solve the acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis (VTI). A perturbation method is used to derive the perturbation formula for complex-valued traveltimes. The application of Shanks transform further enhances the accuracy of approximation. We derive both analytical and numerical solutions to the acoustic eikonal equation. The analytic solution is valid for homogeneous VTI media with moderate anellipticity and strong attenuation and attenuation-anisotropy. The numerical solution is applicable for inhomogeneous attenuating VTI media.

  4. [Usefulness of attenuation correction with transmission source in myocardial SPECT].

    Science.gov (United States)

    Murakawa, Keizo; Katafuchi, Tetsuro; Nishimura, Yoshihiro; Enomoto, Naoyuki; Sago, Masayoshi; Oka, Hisashi

    2006-01-20

    Attenuation correction in SPECT has been used for uniformly absorptive objects like the head. On the other hand, it has seldom been applied to nonuniform absorptive objects like the heart and surrounding lungs because of the difficulty and inaccuracy of data processing. However, since attenuation correction using a transmission source recently became practical, we were able to apply this method to a nonuniform absorptive object. Therefore, we evaluated the usefulness of this attenuation correction system with a transmission source in myocardial SPECT. The dose linearity, defect/normal ratio using a myocardial phantom, and myocardial count distribution in clinical cases was examined with and without the attenuation correction system. We found that all data processed with attenuation correction were better than those without attenuation correction. For example, in myocardial count distribution, while there was a difference between men and women without attenuation correction, which was considered to be caused by differences in body shape, after processing with attenuation correction, myocardial count distribution was almost the same in all cases. In conclusion, these results suggested that attenuation correction with a transmission source was useful in myocardial SPECT.

  5. Damping factor estimation using spin wave attenuation in permalloy film

    Energy Technology Data Exchange (ETDEWEB)

    Manago, Takashi, E-mail: manago@fukuoka-u.ac.jp [Department of Applied Physics, Fukuoka University, 8-19-1 Nanakuma, Jonan, Fukuoka 814-0180 (Japan); Yamanoi, Kazuto [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kasai, Shinya; Mitani, Seiji [National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan)

    2015-05-07

    Damping factor of a Permalloy (Py) thin film is estimated by using the magnetostatic spin wave propagation. The attenuation lengths are obtained by the dependence of the transmission intensity on the antenna distance, and decrease with increasing magnetic fields. The relationship between the attenuation length, damping factor, and external magnetic field is derived theoretically, and the damping factor was determined to be 0.0063 by fitting the magnetic field dependence of the attenuation length, using the derived equation. The obtained value is in good agreement with the general value of Py. Thus, this estimation method of the damping factor using spin waves attenuation can be useful tool for ferromagnetic thin films.

  6. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  7. Turbulence attenuation by large neutrally buoyant particles

    CERN Document Server

    Cisse, Mamadou; Gibert, Mathieu; Bodenschatz, Eberhard; Bec, Jeremie

    2015-01-01

    Turbulence modulation by inertial-range-size, neutrally-buoyant particles is investigated experimentally in a von K\\'arm\\'an flow. Increasing the particle volume fraction $\\Phi_\\mathrm{v}$, maintaining constant impellers Reynolds number attenuates the fluid turbulence. The inertial-range energy transfer rate decreases as $\\propto\\Phi_\\mathrm{v}^{2/3}$, suggesting that only particles located on a surface affect the flow. Small-scale turbulent properties, such as structure functions or acceleration distribution, are unchanged. Finally, measurements hint at the existence of a transition between two different regimes occurring when the average distance between large particles is of the order of the thickness of their boundary layers.

  8. Glutathione attenuates uranyl toxicity in Lactococcus lactis

    Energy Technology Data Exchange (ETDEWEB)

    Fahmy, Karim; Oertel, Jana [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Obeid, M. [Technische Univ. Dresden (Germany); Solioz, M. [Bern Univ. (Switzerland)

    2017-06-01

    We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

  9. Hollow antiresonant fibers with reduced attenuation.

    Science.gov (United States)

    Belardi, Walter; Knight, Jonathan C

    2014-04-01

    An improved design for hollow antiresonant fibers (HAFs) is presented. It consists of adding extra antiresonant glass elements within the air cladding region of an antiresonant hollow-core fiber. We use numerical simulations to compare fiber structures with and without the additional cladding elements in the near- and mid-IR regimes. We show that realizable fiber structures can provide greatly improved performance in terms of leakage and bending losses compared to previously reported antiresonant fibers. At mid-IR wavelengths, the adoption of this novel fiber design will lead to HAFs with reduced bending losses. In the near-IR, this design could lead to the fabrication of HAFs with very low attenuation.

  10. Attenuation of ultrasonic waves in rolled metals

    Science.gov (United States)

    Yang, Liyong; Turner, Joseph A.

    2004-12-01

    Scattering of ultrasonic waves in polycrystals with texture is studied in this article. The attenuations of the three wave modes are determined as a function of dimensionless frequency and propagation direction, respectively, for given orientation distribution coefficients (ODCs). The calculation is done in the case of a statistically orthorhombic sample made up of cubic crystallites. The wave propagation and scattering model is formulated by the Dyson equation using an anisotropic Green's function approach. Within the limits of the first-order smoothing approximation, the Dyson equation is solved in the spatial Fourier transform domain. The results presented are shown to be directional dependent, frequency dependent, and especially dependent on the texture coefficients (ODCs) for the quasilongitudinal and two quasishear waves. The theoretical results presented may be used to improve the understanding of the microstructure during recrystallization processes. .

  11. Gas sensor with attenuated drift characteristic

    Science.gov (United States)

    Chen, Ing-Shin [Danbury, CT; Chen, Philip S. H. [Bethel, CT; Neuner, Jeffrey W [Bethel, CT; Welch, James [Fairfield, CT; Hendrix, Bryan [Danbury, CT; Dimeo, Jr., Frank [Danbury, CT

    2008-05-13

    A sensor with an attenuated drift characteristic, including a layer structure in which a sensing layer has a layer of diffusional barrier material on at least one of its faces. The sensor may for example be constituted as a hydrogen gas sensor including a palladium/yttrium layer structure formed on a micro-hotplate base, with a chromium barrier layer between the yttrium layer and the micro-hotplate, and with a tantalum barrier layer between the yttrium layer and an overlying palladium protective layer. The gas sensor is useful for detection of a target gas in environments susceptible to generation or incursion of such gas, and achieves substantial (e.g., >90%) reduction of signal drift from the gas sensor in extended operation, relative to a corresponding gas sensor lacking the diffusional barrier structure of the invention

  12. Evidence of oxidative attenuation of auxin signalling.

    Science.gov (United States)

    Peer, Wendy Ann; Cheng, Yan; Murphy, Angus S

    2013-06-01

    Indole-3-acetic acid (IAA) is the principle auxin in Arabidopsis and is synthesized primarily in meristems and nodes. Auxin is transported to distal parts of the plant in response to developmental programming or environmental stimuli to activate cell-specific responses. As with any signalling event, the signal must be attenuated to allow the system to reset. Local auxin accumulations are thus reduced by conjugation or catabolism when downstream responses have reached their optima. In most cell types, localized auxin accumulation increases both reactive oxygen species (ROS) and an irreversible catabolic product 2-oxindole-3-acid acid (oxIAA). oxIAA is inactive and does not induce expression of the auxin-responsive reporters DR5 or 2XD0. Here it is shown that oxIAA is not transported from cell to cell, although it appears to be a substrate for the ATP-binding cassette subfamily G (ABCG) transporters that are positioned primarily on the outer lateral surface of the root epidermis. However, oxIAA and oxIAA-Glc levels are higher in ABCB mutants that accumulate auxin due to defective cellular export. Auxin-induced ROS production appears to be at least partially mediated by the NAD(P)H oxidase RbohD. oxIAA levels are higher in mutants that lack ROS-scavenging flavonoids (tt4) and are lower in mutants that accumulate excess flavonols (tt3). These data suggest a model where IAA signalling is attenuated by IAA catabolism to oxIAA. Flavonoids appear to buffer ROS accumulations that occur with localized increases in IAA. This buffering of IAA oxidation would explain some growth responses observed in flavonoid-deficient mutants that cannot be explained by their established role in partially inhibiting auxin transport.

  13. LIVE ATTENUATED VACCINES FOR THE IMMUNOPROPHYLAXIS

    Directory of Open Access Journals (Sweden)

    O. A. Shamsutdinova

    2017-01-01

    Full Text Available The review focuses on the history of the production of live antiviral vaccines and their use for the prevention of infectious diseases. It was noted that before the beginning of the 20th century, only three live vaccines were developed and put into practice — against smallpox, rabies, plague. The discovery of D. Enders, T.H. Weller and F.Ch. Robins of the ability of the polio virus, and then of a number of other viruses, to reproduce in vitro in cell cultures of various types, greatly expanded the studies on the production of attenuated strains of viruses for live vaccines. The historical stages of obtaining and introducing live vaccines for the prevention of smallpox, poliomyelitis, measles, rubella, and mumps are highlighted. Arguments in favor of the use of associated vaccine preparations for the prevention of viral infections are presented. Various variants of the strategy and tactics of using live vaccines, which are used for specific prevention of viral infections in different countries, are described. The review provides information on technological methods for obtaining antiviral vaccines. The publications testifying to the development of specific reactions in immunized vaccine strains of measles, mumps, poliomyelitis and rubella viruses, such as aseptic meningitis (vaccine strains of mumps virus, acute arthritis (vaccine rubella virus strains, temperature reactions, rash (vaccine strains of the virus Measles, vaccine-associated paralytic poliomyelitis (VAPP vaccine vaccine poliovirus. It is particularly noted that the long experience of vaccine prevention both in Russia and abroad convincingly shows that the risk of developing post-vaccination complications is incommensurably lower than the risk of causing harm to health from the corresponding infections. It is concluded that despite introduction of new third and fourth generation vaccines into practice, live attenuated vaccines do not lose their significance and are used in vaccine

  14. CD147/MMP-9通路上调改善自发性高血压大鼠早期心室重构%Upregulation of CD147/MMP-9 pathway attenuates early left ventricular remodeling in rats with spontaneous hypertension

    Institute of Scientific and Technical Information of China (English)

    周万兴; 李博维; 杨小蓉; 周玉良; 谭永锦; 袁丛聪; 宋玉兰; 陈骁; 张卫

    2015-01-01

    目的:探讨CD147/MMP-9通路对自发性高血压大鼠(SHR)早期心室重构的影响。方法:8周龄雄性 SHR 随机分成 SHR、CD147和 CD147+ DOX 组(n =10/组),8周龄雄性 WKY 大鼠为对照组(WKY组,n =10)。 CD147及CD147+ DOX 组予人重组CD147(600 ng/kg 1.5 mL)、SHR 及WKY 组予等量生理盐水,静注,每周1次。 CD147+ DOX组加多西环素(DOX,30 mg/kg,1.5 mL),其他组加生理盐水灌胃每天1次。第56天超声心动图检查、测左心室重量指数(LVWI)、切片(HE、VG染色)观察心肌细胞和胶原增殖、western blot 测心肌 MMP-9、TIMP-1、CD147、Ⅰ和Ⅲ型胶原水平。结果:与 WKY 组比,SHR 组心肌 CD147、MMP-9、MMP-9/TIMP-1明显低(P <0.05);心肌细胞肥大、部分纤维断裂、胞浆溶解坏死,胶原容积分数(CVF)Ⅰ、Ⅲ型胶原显著增高(P <0.05)。而与SHR 组比,CD147组CD147、MMP-9、MMP-9/TIMP-1明显增高,心肌细胞形态和排列改善,LVWI、CVF、Ⅰ、Ⅲ型胶原明显降低。但CD147+DOX 组尽管CD147、MMP-9、MMP-9/TIMP-1比CD147组无明显降低,CVF与Ⅰ、Ⅲ型胶原却明显增高,心肌细胞肥大及纤维断裂现象再次出现。结论:SHR早期心室重构可能与CD147/MMP-9通路受抑制有关,输入CD147上调该通路可以改善该心室重构。%Objective To investigate the effects of CD147/MMP-9 pathway on early left ventricular remodeling Methods 30 healthy eight-week male SHR were divided into 3 groups (n = 10 for each group). SHR group received tail vein injections of normal saline weekly; CD147 group received CD147 of 600 ng·kg-1 weekly; and CD147+DOX group received CD147 of 600 ng/kg weekly and intragastric administration of DOX ( doxycycline ) of 30 mg/kg daily . 10 healthy eight-week male Wistar-Kyoto rats (WKY group) were treated as SHR group. Echocardiography, myocardial sections microscopy examination (HE and VG

  15. Herpes Simplex Vaccines: Prospects of Live-attenuated HSV Vaccines to Combat Genital and Ocular infections

    Science.gov (United States)

    Stanfield, Brent; Kousoulas, Konstantin Gus

    2015-01-01

    Herpes simplex virus type-1 (HSV-1) and its closely related type-2 (HSV-2) viruses cause important clinical manifestations in humans including acute ocular disease and genital infections. These viruses establish latency in the trigeminal ganglionic and dorsal root neurons, respectively. Both viruses are widespread among humans and can frequently reactivate from latency causing disease. Currently, there are no vaccines available against herpes simplex viral infections. However, a number of promising vaccine approaches are being explored in pre-clinical investigations with few progressing to early phase clinical trials. Consensus research findings suggest that robust humoral and cellular immune responses may partially control the frequency of reactivation episodes and reduce clinical symptoms. Live-attenuated viral vaccines have long been considered as a viable option for generating robust and protective immune responses against viral pathogens. Varicella zoster virus (VZV) belongs to the same alphaherpesvirus subfamily with herpes simplex viruses. A live-attenuated VZV vaccine has been extensively used in a prophylactic and therapeutic approach to combat primary and recurrent VZV infection indicating that a similar vaccine approach may be feasible for HSVs. In this review, we summarize pre-clinical approaches to HSV vaccine development and current efforts to test certain vaccine approaches in human clinical trials. Also, we discuss the potential advantages of using a safe, live-attenuated HSV-1 vaccine strain to protect against both HSV-1 and HSV-2 infections. PMID:27114893

  16. Long terminal repeat sequences from virulent and attenuated equine infectious anemia virus demonstrate distinct promoter activities.

    Science.gov (United States)

    Zhou, Tao; Yuan, Xiu-Fang; Hou, Shao-Hua; Tu, Ya-Bin; Peng, Jin-Mei; Wen, Jian-Xin; Qiu, Hua-Ji; Wu, Dong-Lai; Chen, Huan-Chun; Wang, Xiao-Jun; Tong, Guang-Zhi

    2007-09-01

    In the early 1970s, the Chinese Equine Infectious Anemia Virus (EIAV) vaccine, EIAV(DLA), was developed through successive passages of a wild-type virulent virus (EIAV(L)) in donkeys in vivo and then in donkey macrophages in vitro. EIAV attenuation and cell tropism adaptation are associated with changes in both envelope and long terminal repeat (LTR). However, specific LTR changes during Chinese EIAV attenuation have not been demonstrated. In this study, we compared LTR sequences from both virulent and attenuated EIAV strains and documented the diversities of LTR sequence from in vivo and in vitro infections. We found that EIAV LTRs of virulent strains were homologous, while EIAV vaccine have variable LTRs. Interestingly, experimental inoculation of EIAV(DLA) into a horse resulted in a restriction of the LTR variation. Furthermore, LTRs from EIAV(DLA) showed higher Tat transactivated activity than LTRs from virulent strains. By using chimeric clones of wild-type LTR and vaccine LTR, the main difference of activity was mapped to the changes of R region, rather than U3 region.

  17. St. John's Wort Attenuates Colorectal Carcinogenesis in Mice through Suppression of Inflammatory Signaling.

    Science.gov (United States)

    Manna, Soumen K; Golla, Srujana; Golla, Jaya Prakash; Tanaka, Naoki; Cai, Yan; Takahashi, Shogo; Krausz, Kristopher W; Matsubara, Tsutomu; Korboukh, Ilia; Gonzalez, Frank J

    2015-09-01

    Despite widespread use as well as epidemiologic indications, there have been no investigations into the effect of St. John's wort (SJW) extract on colorectal carcinogenesis in vivo. This study reports a systematic evaluation of the impact of dietary supplementation of SJW extract on azoxymethane-induced colorectal carcinogenesis in mice. Mice were fed with either AIN-93G (control) diet or SJW extract-supplemented diet (SJW diet) prior to azoxymethane treatment. SJW diet was found to significantly improve the overall survival of azoxymethane-treated mice. Pretreatment with the SJW diet significantly reduced body weight loss as well as decrease of serum albumin and cholesterol levels associated with azoxymethane-induced colorectal tumorigenesis. SJW diet-fed mice showed a significant decrease in tumor multiplicity along with a decrease in incidence of large tumors and a trend toward decreased total tumor volume in a dose-dependent manner. A short-term study, which examined the effect of SJW prior to rectal bleeding, also showed decrease in colorectal polyps in SJW diet-fed mice. Nuclear factor kappa B (NF-κB) and extracellular signal-regulated kinase (ERK1/2) pathways were attenuated by SJW administration. SJW extract resulted in early and continuous attenuation of these pathways in the colon epithelium of SJW diet-fed mice under both short-term and long-term treatment regimens. In conclusion, this study demonstrated the chemopreventive potential of SJW extract against colorectal cancer through attenuation of proinflammatory processes.

  18. Salmon Thrombin as a Treatment to Attenuate Acute Pain and Promote Tissue Healing by Modulating Local Inflammation

    Science.gov (United States)

    2012-12-01

    trauma and in association with the absence of pain . Early cleavage of PAR1 by thrombin may provide its anti- nociceptive properties. We were very...1-1002 TITLE: Salmon Thrombin as a Treatment to Attenuate Acute Pain and Promote Tissue Healing by Modulating Local Inflammation... Pain and 5a. CONTRACT NUMBER Promote Tissue Healing by Modulating Local Inflammation 5b. GRANT NUMBER W81XWH-10-1-1002 5c. PROGRAM ELEMENT

  19. Wave attenuation in mangroves; a quantitative approach to field observations

    NARCIS (Netherlands)

    Horstman, Erik; Dohmen-Janssen, Catarine M.; Narra, P.M.F.; van den Berg, N.J.F.; Siemerink, M.; Hulscher, Suzanne J.M.H.

    2014-01-01

    Coastal mangroves, dwelling at the interface between land and sea, provide an important contribution to reducing risk from coastal hazards by attenuating incident waves and by trapping and stabilizing sediments. This paper focusses on relations between vegetation densities, wave attenuation rates,

  20. Attenuation of the intensity within a superdeformed band

    CERN Document Server

    Sargeant, A J; Pato, M P; Takigawa, N; Ueda, M

    2002-01-01

    The attenuation of the intraband intensity of a superdeformed band, which results from mixing with normally deformed configurations, is calculated using reaction theory. It is found that the sharp increase of the attenuation is mostly due to the tunnelling through a spin dependent barrier and not to the chaotic nature of the normally deformed states.

  1. Periportal low-attenuation: a CT sign of lymphatic obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Kim, Chong Soo; Yang, Doo Hyun; Lee, Sang Yong; Lee, Young Whan; Chung, Gyung Ho; Han, Young Min; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

    1995-07-15

    Periportal low attenuation, defined as a low attenuation rim around the portal vein and its branches which is seen on contrast material-enhanced CT scans, has been described in a variety of conditions. We tried to document that lymphatic obstruction is one of the major cause of periportal low attenuation. We retrospectively analyzed 57 cases of periportal low attenuation of abdominal CT scans and also reviewed the surgical records in 32 cases. Lymph node enlargement in the hepatoduodenal ligament which is a main lymphatic channel from the liver were analyzed the calculated the ratio of the transeverse diameter between the inferior vena cava and the aorta at the level of right adrenal gland. After complete surgical interruption of the lymphatic drainage from the liver in a dog, follow up CT scans were obtained and correlated with pathologic findings. Fifty patients (88%) had underlying disease which could cause impairment of lymphatic drainage. Periportal low attenuation was identified in several clinical conditions, including surgical lymph node dissection, lymphadenopathy in the hepatoduodenal ligament, blunt trauma. In animal model, CT scan showed prominent periportal low attenuation at 5 days after surgery. Histologic examination revealed numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches. One of the major cause of periportal low attenuation was impaired lymphatic drainage and periportal low attenuation corresponding to the numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches.

  2. A Precision Variable, Double Prism Attenuator for CO(2) Lasers.

    Science.gov (United States)

    Oseki, T; Saito, S

    1971-01-01

    A precision, double prism attenuator for CO(2) lasers, calibrated by its gap capacitance, was constructed to evaluate its possible use as a standard for attenuation measurements. It was found that the accuracy was about 0.1 dB with a dynamic range of about 40 dB.

  3. Ultrasound attenuation dependence on air compression or expansion processes

    NARCIS (Netherlands)

    Jakevicius, L.; Demcenko, A.; Mardosaite, R.

    2010-01-01

    In this work variation of ultrasonic attenuation coefficient is analyzed in terms of air compression or expansion processes. In closed spaces changing air volume, the ultrasound attenuation coefficient depends on thermodynamic processes which occur during the air volume change. Two limiting cases ar

  4. Excess attenuation of an acoustic beam by turbulence.

    Science.gov (United States)

    Pan, Naixian

    2003-12-01

    A theory based on the concept of a spatial sinusoidal diffraction grating is presented for the estimation of the excess attenuation in an acoustic beam. The equation of the excess attenuation coefficient shows that the excess attenuation of acoustic beam not only depends on the turbulence but also depends on the application parameters such as the beam width, the beam orientation and whether for forward propagation or back scatter propagation. Analysis shows that the excess attenuation appears to have a frequency dependence of cube-root. The expression for the excess attenuation coefficient has been used in the estimations of the temperature structure coefficient, C(T)2, in sodar sounding. The correction of C(T)2 values for excess attenuation reduces their errors greatly. Published profiles of temperature structure coefficient and the velocity structure coefficient in convective conditions are used to test our theory, which is compared with the theory by Brown and Clifford. The excess attenuation due to scattering from turbulence and atmospheric absorption are both taken into account in sodar data processing for deducing the contribution of the lower atmosphere to seeing, which is the sharpness of a telescope image determined by the degree of turbulence in the Earth's atmosphere. The comparison between the contributions of the lowest 300-m layer to seeing with that of the whole atmosphere supports the reasonableness of our estimation of excess attenuation.

  5. When and why mimicry is facilitated and attenuated

    NARCIS (Netherlands)

    Stel, M.; Van Dijk, Eric; Van Baaren, Rick B.

    2016-01-01

    Although people tend to mimic others automatically, mimicry is facilitated or attenuated depending on the specific context. In the current paper, the authors discuss when mimicry is facilitated and attenuated depending on characteristics of situations, targets, and observers. On the basis of the

  6. When and Why Mimicry is Facilitated and Attenuated

    NARCIS (Netherlands)

    Stel, Mariëlle; van Dijk, Eric; van Baaren, Rick B.

    2016-01-01

    Although people tend to mimic others automatically, mimicry is facilitated or attenuated depending on the specific context. In the current paper, the authors discuss when mimicry is facilitated and attenuated depending on characteristics of situations, targets, and observers. On the basis of the

  7. Flux attenuation at NREL's High-Flux Solar Furnace

    Science.gov (United States)

    Bingham, Carl E.; Scholl, Kent L.; Lewandowski, Allan A.

    1994-10-01

    The High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) has a faceted primary concentrator and a long focal-length-to-diameter ratio (due to its off-axis design). Each primary facet can be aimed individually to produce different flux distributions at the target plane. Two different types of attenuators are used depending on the flux distribution. A sliding-plate attenuator is used primarily when the facets are aimed at the same target point. The alternate attenuator resembles a venetian blind. Both attenuators are located between the concentrator and the focal point. The venetian-blind attenuator is primarily used to control the levels of sunlight failing on a target when the primary concentrators are not focused to a single point. This paper will demonstrate the problem of using the sliding-plate attenuator with a faceted concentrator when the facets are not aimed at the same target point. We will show that although the alternate attenuator necessarily blocks a certain amount of incoming sunlight, even when fully open, it provides a more even attenuation of the flux for alternate aiming strategies.

  8. Ultrasonic velocity and attenuation anisotropy of shales, Whitby, United Kingdom

    NARCIS (Netherlands)

    Zhubayev, A.; Houben, M.E.; Smeulders, D.M.J.; Barnhoorn, A.

    2015-01-01

    We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity and attenuation (Q−1) anisotropy of P- and S-waves in dry Whitby Mudstone samples as a function of stress. We found the degree of anisotropy to be as large as 70% for velocity and attenuation. The sensitivity of P-w

  9. Ultrasonic velocity and attenuation anisotropy of shales, Whitby, United Kingdom

    NARCIS (Netherlands)

    Zhubayev, Alimzhan; Houben, M.E.; Smeulders, David; Barnhoorn, A.

    2016-01-01

    We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity and attenuation (Q−1) anisotropy of P- and S-waves in dry Whitby Mudstone samples as a function of stress. We found the degree of anisotropy to be as large as 70% for velocity and attenuation. The sensitivity of P-w

  10. Light attenuation characteristics of glacially-fed lakes

    Science.gov (United States)

    Rose, Kevin C.; Hamilton, David P.; Williamson, Craig E.; McBride, Chris G.; Fischer, Janet M.; Olson, Mark H.; Saros, Jasmine E.; Allan, Mathew G.; Cabrol, Nathalie

    2014-07-01

    Transparency is a fundamental characteristic of aquatic ecosystems and is highly responsive to changes in climate and land use. The transparency of glacially-fed lakes may be a particularly sensitive sentinel characteristic of these changes. However, little is known about the relative contributions of glacial flour versus other factors affecting light attenuation in these lakes. We sampled 18 glacially-fed lakes in Chile, New Zealand, and the U.S. and Canadian Rocky Mountains to characterize how dissolved absorption, algal biomass (approximated by chlorophyll a), water, and glacial flour contributed to attenuation of ultraviolet radiation (UVR) and photosynthetically active radiation (PAR, 400-700 nm). Variation in attenuation across lakes was related to turbidity, which we used as a proxy for the concentration of glacial flour. Turbidity-specific diffuse attenuation coefficients increased with decreasing wavelength and distance from glaciers. Regional differences in turbidity-specific diffuse attenuation coefficients were observed in short UVR wavelengths (305 and 320 nm) but not at longer UVR wavelengths (380 nm) or PAR. Dissolved absorption coefficients, which are closely correlated with diffuse attenuation coefficients in most non-glacially-fed lakes, represented only about one quarter of diffuse attenuation coefficients in study lakes here, whereas glacial flour contributed about two thirds across UVR and PAR. Understanding the optical characteristics of substances that regulate light attenuation in glacially-fed lakes will help elucidate the signals that these systems provide of broader environmental changes and forecast the effects of climate change on these aquatic ecosystems.

  11. Attenuated radon transform: theory and application in medicine and biology

    Energy Technology Data Exchange (ETDEWEB)

    Gullberg, G.T.

    1979-06-01

    A detailed analysis is given of the properties of the attenuated Radon transform and of how increases in photon attenuation influence the numerical accuracy and computation efficiency of iterative and convolution algorithms used to determine its inversion. The practical applications for this work involve quantitative assessment of the distribution of injected radiopharmaceuticals and radionuclides in man and animals for basic physiological and biochemical studies as well as clinical studies in nuclear medicine. A mathematical structure is developed using function theory and the theory of linear operators on Hilbert spaces which lends itself to better understanding the spectral properties of the attenuated Radon transform. The continuous attenuated Radon transform reduces to a matrix operator for discrete angular and lateral sampling, and the reconstruction problem reduces to a system of linear equations. For the situation of variable attenuation coefficient frequently found in nuclear medicine applications of imaging the heart and chest, the procedure developed in this thesis involves iterative techniques of performing the generalized inverse. For constant attenuation coefficient less than 0.15 cm/sup -1/, convolution methods can reliably reconstruct a 30 cm object with 0.5 cm resolution. However, for high attenuation coefficients or for the situation where there is variable attenuation such as reconstruction of distribution of isotopes in the heart, iterative techniques developed in this thesis give the best results. (ERB)

  12. Wave attenuation in mangroves; a quantitative approach to field observations

    NARCIS (Netherlands)

    Horstman, E.M.; Dohmen-Janssen, C.M.; Narra, P.M.F.; Berg, van den N.J.F.; Siemerink, M.; Hulscher, S.J.M.H.

    2014-01-01

    Coastal mangroves, dwelling at the interface between land and sea, provide an important contribution to reducing risk from coastal hazards by attenuating incident waves and by trapping and stabilizing sediments. This paper focusses on relations between vegetation densities, wave attenuation rates, s

  13. Doxycycline Attenuated Pulmonary Fibrosis Induced by Bleomycin in Mice

    OpenAIRE

    Fujita, Masaki; Ye, Qing; Ouchi, Hiroshi; Harada, Eiji; Inoshima, Ichiro; Kuwano, Kazuyoshi; Nakanishi, Yoichi

    2006-01-01

    The administration of doxycycline prior to bleomycin in mice attenuated pulmonary fibrosis. Bronchoalveolar neutrophil influx and gelatinase activity, but not caseinolytic activity, were attenuated by doxycycline. Established fibrosis was not affected by doxycycline. Thus, doxycycline might be useful for slowing down pulmonary fibrosis by biological activity other than antibacterial activity.

  14. Review and prospect of research on hydraulic pulsation attenuator

    Science.gov (United States)

    Shan, Chang-ji; Zhao, Qi-jun; Dai, Ting-ting; Bian, Yi-duo; Cai, Yan

    2017-09-01

    The pressure pulsation attenuator is able to decrease the fluid fluctuation of the hydraulic pump effectively, so it is widely used in construction machinery. This paper reviews the history and progresses of the research on the pressure pulsation attenuator in China and overseas, summarizes its two types: H-type rigid structure and built-in flexible material, meanwhile, discusses its future research area.

  15. 16 CFR 1203.17 - Impact attenuation test.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Impact attenuation test. 1203.17 Section... SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... the acceleration of the test headform during impact. Acceleration is measured with a...

  16. Intrinsic and scattering attenuation images of Usu volcano, Japan

    Science.gov (United States)

    Prudencio, J.; Taira, T.; Aoki, Y.; Aoyama, H.; Onizawa, S.

    2017-04-01

    We present intrinsic- and scattering-Q attenuation images for Usu volcano (Japan) by analyzing over 1800 vertical seismograms. By fitting the observed envelopes to the diffusion model, we obtained intrinsic and scattering attenuation values at three different frequency bands. Using a back-projection method and assuming a Gaussian-type weighting function, we obtained the 2D images of intrinsic and scattering attenuation. Resolution tests confirm the robustness and reliability of the obtained images. We found that scattering attenuation is the dominant process of energy loss in the frequency range analyzed, which suggests strong spatial heterogeneity. The resultant scattering attenuation images show an increase of attenuation toward the southwest from Toya caldera, which may correspond to deepening of the basement. We also identify an area of low intrinsic and scattering attenuation at the summit of Usu volcano which could be associated with old magma intrusions. Our results demonstrate a strong spatial relation between structural heterogeneities and attenuation processes in volcanic areas and confirm the efficiency of the method which can be used together with conventional imaging techniques.

  17. The attenuation anisotropy of mudstones and shales in subsurface formations

    Institute of Scientific and Technical Information of China (English)

    SHI Ge; DENG Jixin

    2005-01-01

    We have measured the relationships in the laboratorial condition between the attenuation in three samples of mudstones and shales as well as two samples of layered sandstones and the alteration in direction, confining pressure and pore fluid. The relative contributions of different attenuation mechanisms are also discussed. Studies show that the attenuation in dry and saturated samples is strongly related to pressure and direction. The attenuation coefficient of P-wave propagating parallel to bedding (PH) is less than that of P-wave propagating vertical to bedding (PV), while the attenuation coefficient of S-wave both propagating and vibrating parallel to bedding (SH) and that of S-wave propagating vertical to bedding while vibrating parallel to bedding (SV1) are less than that of S-wave propagating parallel to bedding while vibrating vertical to bedding (SV). Under oil saturated conditions, the Biot flow attenuation acts as the dominant mechanism for waves propagating parallel to bedding, while the frame anelastic attenuation and squirt flow attenuation seem to play important roles in condition of propagation vertical to bedding.

  18. Natural attenuation: CERCLA, RBCAs, and the future of environmental remediation

    Energy Technology Data Exchange (ETDEWEB)

    Brady, P.V.; Borns, D.J. [Sandia National Labs., Albuquerque, NM (United States); Brady, M.V. [McDonough, Holland, and Allen, Sacramento, CA (United States)

    1998-12-31

    Introduces the concept of natural attenuation -- the tendency of soils to severely limit the toxicity of many types of hazardous waste. This book reviews and updates the most recent findings from the field and lab, and shows how natural attenuation is rapidly changing the direction and focus of environmental remediation.

  19. Effect of lead attenuators on dose in homogeneous phantoms

    Energy Technology Data Exchange (ETDEWEB)

    El-Khatib, E.E.; Podgorsak, E.B.; Pla, C.

    1986-11-01

    In radiotherapy, the radiation beam is sometimes shaped so as to deliver different doses to different organs or give a homogeneous dose to structures of different densities. This objective is achieved by the use of attenuating materials introduced into the beam. These attenuators alter the primary as well as the scattered radiation components of the beam. There is at present no accurate method of dose calculation for these situations. Most calculations are performed considering only the effect of the attenuators on the primary radiation beam and can produce large errors in dosimetry. In the present study, the broad beam attenuation is investigated in homogeneous phantoms for various radiation field sizes, photon beam energies, and depths in phantom. A calculational method taking account of primary as well as first scatter radiation is developed. This method predicts reasonably well the transmission through lead attenuators for the various experimental conditions investigated.

  20. EFFECTS OF RAIN ATTENUATION ON SATELLITE COMMUNICATION LINK

    Directory of Open Access Journals (Sweden)

    G. N. Ezeh

    2014-06-01

    Full Text Available Rain attenuation is a major challenge to microwave satellite communication especially at frequencies above 10 GHz, causing unavailability of signals most of the time. Rain attenuation predictions have become one of the vital considerations while setting up a satellite communication link. In this study, rain attenuation models, cumulative distribution curves and other analytical tools for successful prediction of rain attenuation are presented. A three year Rain rate data was obtained from the Nigeria Meteorological Agency (NIMET database in addition to experimental data. Of the three prediction models used in the study, Ajayi model gave the range of values closest to the experimental data. A correctional factor was determined as 1.0988 and used to modify the Ajayi model. This modification to Ajayi’s model enabled its rain attenuation values conform more closely to the experimental result.

  1. Attenuation compensation of GPR signal based on generalized S-transform

    Science.gov (United States)

    Hu, Shufan; Zhao, Yonghui; Qin, Tan; An, Cong

    2017-04-01

    Ground penetrating radar (GPR), as a nondestructive technique, has been widely used in civil engineering. Due to the complexity of the engineering conditions and attenuation of the GPR signal with depth, the radargram contained deep information usually shows a low resolution and S/N ratio. It might be one of the most difficult problems to GPR data interpretation, which limits the further application of the GPR method in civil engineering. The traditional way, such as a manual or automatic gain technique, was commonly used to enhance the weak GPR signal of deep target. However, due to the non-stationary of GPR signal, only the energy compensation in time or frequency domain may be not appropriate while using the manual or automatic gain methods. In this sense, neither the automatic gain compensation nor the other gain method seem likely difficult to obtain better results. In fact, it's not reasonable to separate the information in time and frequency domain from GPR data. The S-transform is a time-frequency analysis technique, which makes it possible for analyzing the GPR signal in time and frequency domain simultaneously. In addition, use S-transform to GPR data can preserve the original information in a wide frequency range. Here, we proposed a generalized S-transform based on exponential function and used it to the attenuation compensation of GPR signal. Firstly, the GPR data were transform to time-frequency domain using generalized S-transform trace by trace. Then the high-frequency component will be weighted at each time sample according to the attenuation ratio of low-frequency component. In this way the spectrum difference of each frequency component between late and early sampling time have the same ratio factor, which greatly compensates the attenuation of high-frequency component. Finally, the well compensated GPR data were obtained by inverse S-transform. Synthetic and real GPR data were used to verify the effectiveness and robustness of the proposed

  2. Seismic attenuation of the inner core: Viscoelastic or stratigraphic?

    Science.gov (United States)

    Cormier, V.F.; Xu, L.; Choy, G.L.

    1998-01-01

    Broadband velocity waveforms of PKIKP in the distance range 150??to 180??are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in measured Q-1 exceeds individual error estimates, suggesting significant variation in attenuation with path. These results are interpreted by (1) viscoelasticity, in which the relaxation spectrum has a low-frequency corner near or slightly above the frequency band of short-period body waves, and by (2) stratigraphic (scattering) attenuation, in which attenuation and pulse broadening are caused by the interference of scattered multiples in a velocity structure having rapid fluctuations along a PKIKP path. In the scattering interpretation, PKIKP attenuation is only weakly affected by the intrinsic shear attenuation measured in the free-oscillation band. Instead, its frequency dependence, path variations, and fluctuations are all explained by scattering attenuation in a heterogeneous fabric resulting from solidification texturing of intrinsically anisotropic iron. The requisite fabric may consist of either single or ordered groups of crystals with P velocity differences of at least 5% and as much as 12% between two crystallographic axes at scale lengths of 0.5 to 2 km in the direction parallel to the axis of rotation and longer in the cylindrically radial direction, perpendicular to the axis of rotation.Broadband velocity waveforms of PKIKP in the distance range 150?? to 180?? are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in the measured Q-1 exceeds individual error estimates, indicating significant variation in attenuation with path. The results are interpreted by viscoelasticity and stratigraphic (scattering) attenuation.

  3. Whole-body PET/MRI: The effect of bone attenuation during MR-based attenuation correction in oncology imaging

    DEFF Research Database (Denmark)

    Aznar, M.C.; Sersar, Rachida; Saabye, J.

    2014-01-01

    Purpose: In combined PET/MRI standard PET attenuation correction (AC) is based on tissue segmentation following dedicated MR sequencing and, typically, bone tissue is not represented. We evaluate PET quantification in whole-body (WB)-PET/MRI following MR-AC without considering bone attenuation an...

  4. Biomarkers of safety and immune protection for genetically modified live attenuated Leishmania vaccines against visceral leishmaniasis-Discovery and implications

    Directory of Open Access Journals (Sweden)

    Sreenivas eGannavaram

    2014-05-01

    Full Text Available Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, sub-unit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in L. donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen1-/- in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated

  5. Impact of attenuation correction and gated acquisition in SPECT myocardial perfusion imaging: results of the multicentre SPAG (SPECT Attenuation Correction vs Gated) study

    Energy Technology Data Exchange (ETDEWEB)

    Genovesi, Dario; Giorgetti, Assuero; Gimelli, Alessia; Kusch, Annette; D' Aragona Tagliavia, Irene; Casagranda, Mirta; Marzullo, Paolo [Fondazione CNR-Regione Toscana ' ' G. Monasterio' ' , Nuclear Medicine, Pisa (Italy); Cannizzaro, Giorgio [A.O.V. Cervello, Nuclear Medicine, Palermo (Italy); Giubbini, Raffaele; Bertagna, Francesco [Spedali Civili, Nuclear Medicine, Brescia (Italy); Fagioli, Giorgio; Rossi, Massimiliano; Romeo, Annadina [Ospedale Maggiore, Nuclear Medicine, Bologna (Italy); Bertolaccini, Pietro; Bonini, Rita [Ospedale SS Giacomo e Cristoforo, Nuclear Medicine, Massa (Italy)

    2011-10-15

    In clinical myocardial single photon emission computed tomography (SPECT), attenuation artefacts may cause a loss of specificity in the identification of diseased vessels that can be corrected by means of gated SPECT (GSPECT) acquisition or CT attenuation correction (AC). The purpose of this multicentre study was to assess the impact of GSPECT and AC on the diagnostic performance of myocardial scintigraphy, according to patient's sex, body mass index (BMI) and site of coronary artery disease (CAD). We studied a group of 104 patients who underwent coronary angiography within 1 month before or after the SPECT study. Patients with a BMI > 27 were considered ''overweight''. Attenuation-corrected and standard GSPECT early images were randomly interpreted by three readers blinded to the clinical data. In the whole group, GSPECT and AC showed a diagnostic accuracy of 86.5% (sensitivity 82%, specificity 93%) and 77% (sensitivity 75.4%, specificity 81.4%), respectively (p < 0.05). In women, when anterior ischaemia was matched with CAD, AC failed to show any increase in specificity (AC 63.6% vs GSPECT 63.6%) with evident loss of sensitivity (AC 72.7% vs GSPECT 90.9%). AC significantly improved SPECT specificity in the identification of right CAD in overweight men (AC 100% vs GSPECT 66.7%, p <0.05). AC improved specificity in the evaluation of right CAD in overweight men. In the other evaluable subgroups specificity was not significantly affected while sensitivity was frequently reduced. (orig.)

  6. Silibinin attenuates allergic airway inflammation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yun Ho [Department of Anatomy, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Jin, Guang Yu [Department of Radiology, Yanbian University Hospital, YanJi 133002 (China); Guo, Hui Shu [Centralab, The First Affiliated Hospital of Dalian Medical University, Dalian 116011 (China); Piao, Hong Mei [Department of Respiratory Medicine, Yanbian University Hospital, YanJi 133000 (China); Li, Liang chang; Li, Guang Zhao [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China); Lin, Zhen Hua [Department of Pathology, Yanbian University School of Basic Medical Sciences, YanJi 133000 (China); Yan, Guang Hai, E-mail: ghyan@ybu.edu.cn [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. Black-Right-Pointing-Pointer Silibinin reduces the levels of various cytokines into the lung of allergic mice. Black-Right-Pointing-Pointer Silibinin prevents the development of airway hyperresponsiveness in allergic mice. Black-Right-Pointing-Pointer Silibinin suppresses NF-{kappa}B transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-{kappa}B) pathway. Because NF-{kappa}B activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-{kappa}B activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-{kappa}B activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  7. A prototype piecewise-linear dynamic attenuator

    Science.gov (United States)

    Hsieh, Scott S.; Peng, Mark V.; May, Christopher A.; Shunhavanich, Picha; Fleischmann, Dominik; Pelc, Norbert J.

    2016-07-01

    The piecewise-linear dynamic attenuator has been proposed as a mechanism in CT scanning for personalizing the x-ray illumination on a patient- and application-specific basis. Previous simulations have shown benefits in image quality, scatter, and dose objectives. We report on the first prototype implementation. This prototype is reduced in scale and speed and is integrated into a tabletop CT system with a smaller field of view (25 cm) and longer scan time (42 s) compared to a clinical system. Stainless steel wedges were machined and affixed to linear actuators, which were in turn held secure by a frame built using rapid prototyping technologies. The actuators were computer-controlled, with characteristic noise of about 100 microns. Simulations suggest that in a clinical setting, the impact of actuator noise could lead to artifacts of only 1 HU. Ring artifacts were minimized by careful design of the wedges. A water beam hardening correction was applied and the scan was collimated to reduce scatter. We scanned a 16 cm water cylinder phantom as well as an anthropomorphic pediatric phantom. The artifacts present in reconstructed images are comparable to artifacts normally seen with this tabletop system. Compared to a flat-field reference scan, increased detectability at reduced dose is shown and streaking is reduced. Artifacts are modest in our images and further refinement is possible. Issues of mechanical speed and stability in the challenging clinical CT environment will be addressed in a future design.

  8. Photoacoustic imaging taking into account thermodynamic attenuation

    Science.gov (United States)

    Acosta, Sebastián; Montalto, Carlos

    2016-11-01

    In this paper we consider a mathematical model for photoacoustic imaging which takes into account attenuation due to thermodynamic dissipation. The propagation of acoustic (compressional) waves is governed by a scalar wave equation coupled to the heat equation for the excess temperature. We seek to recover the initial acoustic profile from knowledge of acoustic measurements at the boundary. We recognize that this inverse problem is a special case of boundary observability for a thermoelastic system. This leads to the use of control/observability tools to prove the unique and stable recovery of the initial acoustic profile in the weak thermoelastic coupling regime. This approach is constructive, yielding a solvable equation for the unknown acoustic profile. Moreover, the solution to this reconstruction equation can be approximated numerically using the conjugate gradient method. If certain geometrical conditions for the wave speed are satisfied, this approach is well-suited for variable media and for measurements on a subset of the boundary. We also present a numerical implementation of the proposed reconstruction algorithm.

  9. Statins attenuate polymethylmethacrylate-mediated monocyte activation.

    LENUS (Irish Health Repository)

    Laing, Alan J

    2012-02-03

    BACKGROUND: Periprosthetic osteolysis precipitates aseptic loosening of components, increases the risk of periprosthetic fracture and, through massive bone loss, complicates revision surgery and ultimately is the primary cause for failure of joint arthroplasty. The anti-inflammatory properties of HMG-CoA reductase inhibitors belonging to the statin family are well recognized. We investigated a possible role for status in initiating the first stage of the osteolytic cycle, namely monocytic activation. METHODS: We used an in vitro model of the human monocyte\\/macrophage inflammatory response to poly-methylmethacrylate (PMMA) particles after pretreat-ing cells with cerivastatin, a potent member of the statin family. Cell activation based upon production of TNF-alpha and MCP-1 cytokines was analyzed and the intracellular Raf-MEK-ERK signal transduction pathway was evaluated using western blot analysis, to identify its role in cell activation and in any cerivastatin effects observed. RESULTS: We found that pretreatment with cerivastatin significantly abrogates the production of inflammatory cytokines TNF-alpha and MCP-1 by human monocytes in response to polymethylmethacrylate particle activation. This inflammatory activation and attenuation appear to be mediated through the intracellular Raf-MEK-ERK pathway. INTERPRETATION: We propose that by intervening at the upstream activation stage, subsequent osteoclast activation and osteolysis can be suppressed. We believe that the anti-inflammatory properties of statins may potentially play a prophylactic role in the setting of aseptic loosening, and in so doing increase implant longevity.

  10. Agmatine attenuates silica-induced pulmonary fibrosis.

    Science.gov (United States)

    El-Agamy, D S; Sharawy, M H; Ammar, E M

    2014-06-01

    There is a large body of evidence that nitric oxide (NO) formation is implicated in mediating silica-induced pulmonary fibrosis. As a reactive free radical, NO may not only contribute to lung parenchymal tissue injury but also has the ability to combine with superoxide and form a highly reactive toxic species peroxynitrite that can induce extensive cellular toxicity in the lung tissues. This study aimed to explore the effect of agmatine, a known NO synthase inhibitor, on silica-induced pulmonary fibrosis in rats. Male Sprague Dawley rats were treated with agmatine for 60 days following a single intranasal instillation of silica suspension (50 mg in 0.1 ml saline/rat). The results revealed that agmatine attenuated silica-induced lung inflammation as it decreased the lung wet/dry weight ratio, protein concentration, and the accumulation of the inflammatory cells in the bronchoalveolar lavage fluid. Agmatine showed antifibrotic activity as it decreased total hydroxyproline content of the lung and reduced silica-mediated lung inflammation and fibrosis in lung histopathological specimen. In addition, agmatine significantly increased superoxide dismutase (p pulmonary nitrite/nitrate as well as tumor necrosis factor α. Collectively, these results demonstrate the protective effects of agmatine against the silica-induced lung fibrosis that may be attributed to its ability to counteract the NO production, lipid peroxidation, and regulate cytokine effects.

  11. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    BHALLA VYOMA; SINGH DEVRAJ; JAIN S K; KUMAR RAJ

    2016-06-01

    The present paper deals with the theoretical calculation of mechanical and thermophysical properties of rare-earth monoarsenides, XAs (X: Np, Pu, Th and U) using elastic constants as the input parameters. These second- and third-order elastic constants (SOECs and TOECs) are determinedin the temperature range 100–500K using Coulomb and Born–Mayer potential upto second nearest neighbours. In order to provide the link between mechanical and dynamical behaviour of crystals, parameters such as Young’s modulus, bulk modulus, Poisson’s ratio etc. are also calculated.In addition, the Cauchy relationship is obeyed by the chosen monoarsenides and are fairly anisotropic, which results in the measurement of longitudinal and shear wave velocities along $\\langle100 \\rangle$, $\\langle110\\rangle$ and $\\langle 111\\rangle$ directions. The toughness/fracture $(G/BT)$ ratio is greater than 0.60, which implies that XAs compounds are brittle at room temperature. Further, the Debye temperature is computed using Debye average velocity as the input parameter. It helps in the characterization of lattice vibrations of a solid. In this work, ultrasonic attenuation due to phonon–phonon interaction$\\alpha/f^2_{\\rm p−p}$ and thermoelastic loss $\\alpha/f ^{2}$th are computed for XAs from 100 to 500K using Mason’s theory. It further helps in evaluating the microstructural properties of the chosen materials. The obtained results indicate that XAs is mechanically stable and are compared with data availablein the literature.

  12. Atorvastatin attenuates oxidative stress in Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Cai Zhiyou; Yan Yong; Wang Yonglong

    2008-01-01

    Objective: To investigate serum level of SOD, MDA, ox-LDL, AchE and Ach in AD, to study atorvastatin influence on serum level of SOD, MDA, ox-LDL, AchE and Acb in AD and its neuroprotection mechanisms. Methods Subjects were divided into: normal blood lipid level group with Alzheimer's disease (A), higher blood lipid level group with Alzheimer's disease (AH), normal blood lipid level Alzheimer's disease group with atorvastatin treeatment (AT),higher blood lipid level Alzheimer's disease group with atorvastatin treeatment(AHT). Ox-LDL was measured by enzyme linked immunosorbent assay; SOD, MDA, ox-LDL, AchE, Ach and blood lipid level in AD was measured by biochemistry. Results: The serum level of MDA, AchE in AH group after atorvastatin treatment is lower ;The serum level of SOD, Ach in AH group is more increased than that of in A group; The serum level of ox-LDL in AH, A groups is lower than that of in A group; The dementia degree is lower after atorvastatin treatment. Conclusion: Atorvastatin can decrease serum level of MDA, AchE and ox-LDL, and increase that of SOD, Acb, and attenuate dementia symptom in AD, especially, with hyperlipemia. The hypothesis of atorvastatin neuroprotection is concluded that atorvastatin may restrain free radical reaction and retard oxidation in AD.

  13. Endothelium attenuates ethanol induced vasoconstriction of arteries

    Energy Technology Data Exchange (ETDEWEB)

    Morley, D.; Bove, A.A.; Walter, J. (Temple School of Medicine, Philadelphia, PA (United States))

    1990-02-26

    The authors have previously demonstrated that clinically relevant doses of ethanol (ETH) caused significant vasoconstriction of rabbit thoracic aorta. This study examined the role of endothelium in ethanol vasoconstriction. Thoracic aorta was harvested from 3 New Zealand White rabbits after anesthetization with sodium pentobarbital. Twelve aortic 3 mm rings were mounted in organ baths attached to force transducers and recording apparatus. Six of the twelve rings were denuded. Denudation was confirmed by challenge with acetylcholine (10-4 M). Resting tension was set at 10 grams and the rings equilibrated in 37 C Krebs-Heinsleit solution for 2 hours. Then, the response to norepinephrine (NE) was established (10-8 to 10-5 M). After reattaining resting tension, the response to ETH (500-2,500 ug/ml) was recorded. ETH produced significant vasoconstriction in both non-denuded (48{plus minus}7% of NE max) and denuded (58{plus minus}2% of NE max) arteries. Vasoconstriction was significantly higher in the denuded condition. The authors conclude that the predominant ETH action on arteries is based in vascular smooth muscle although endothelium acts to attenuate the ETH induced vasoconstrictor response.

  14. Sulforaphane attenuates EGFR signaling in NSCLC cells.

    Science.gov (United States)

    Chen, Chi-Yuan; Yu, Zhu-Yun; Chuang, Yen-Shu; Huang, Rui-Mei; Wang, Tzu-Chien V

    2015-06-03

    EGFR, a receptor tyrosine kinase (RTK), is frequently overexpressed and mutated in non-small cell lung cancer (NSCLC). Tyrosine kinase inhibitors (TKIs) have been widely used in the treatment of many cancers, including NSCLC. However, intrinsic and acquired resistance to TKI remains a common obstacle. One strategy that may help overcome EGFR-TKI resistance is to target EGFR for degradation. As EGFR is a client protein of heat-shock protein 90 (HSP90) and sulforaphane is known to functionally regulate HSP90, we hypothesized that sulforaphane could attenuate EGFR-related signaling and potentially be used to treat NSCLC. Our study revealed that sulforaphane displayed antitumor activity against NSCLC cells both in vitro and in vivo. The sensitivity of NSCLC cells to sulforaphane appeared to positively correlate with the inhibition of EGFR-related signaling, which was attributed to the increased proteasomal degradation of EGFR. Combined treatment of NSCLC cells with sulforaphane plus another HSP90 inhibitor (17-AAG) enhanced the inhibition of EGFR-related signaling both in vitro and in vivo. We have shown that sulforaphane is a novel inhibitory modulator of EGFR expression and is effective in inhibiting the tumor growth of EGFR-TKI-resistant NSCLC cells. Our findings suggest that sulforaphane should be further explored for its potential clinical applications against NSCLC.

  15. Disulfiram attenuates osteoclast differentiation in vitro: a potential antiresorptive agent.

    Science.gov (United States)

    Ying, Hua; Qin, An; Cheng, Tak S; Pavlos, Nathan J; Rea, Sarah; Dai, Kerong; Zheng, Ming H

    2015-01-01

    Disulfiram (DSF), a cysteine modifying compound, has long been clinically employed for the treatment of alcohol addiction. Mechanistically, DSF acts as a modulator of MAPK and NF-κB pathways signaling pathways. While these pathways are crucial for osteoclast (OC) differentiation, the potential influence of DSF on OC formation and function has not been directly assessed. Here, we explore the pharmacological effects of DSF on OC differentiation, activity and the modulation of osteoclastogenic signaling cascades. We first analyzed cytotoxicity of DSF on bone marrow monocytes isolated from C57BL/6J mice. Upon the establishment of optimal dosage, we conducted osteoclastogenesis and bone resorption assays in the presence or absence of DSF treatment. Luciferase assays in RAW264.7 cells were used to examine the effects of DSF on major transcription factors activation. Western blot, reverse transcription polymerase chain reaction, intracellular acidification and proton influx assays were employed to further dissect the underlying mechanism. DSF treatment dose-dependently inhibited both mouse and human osteoclastogenesis, especially at early stages of differentiation. This inhibition correlated with a decrease in the expression of key osteoclastic marker genes including CtsK, TRAP, DC-STAMP and Atp6v0d2 as well as a reduction in bone resorption in vitro. Suppression of OC differentiation was found to be due, at least in part, to the blockade of several key receptor activators of nuclear factor kappa-B ligand (RANKL)-signaling pathways including ERK, NF-κB and NFATc1. On the other hand, DSF failed to suppress intracellular acidification and proton influx in mouse and human osteoclasts using acridine orange quenching and microsome-based proton transport assays. Our findings indicate that DSF attenuates OC differentiation via the collective suppression of several key RANKL-mediated signaling cascades, thus making it an attractive agent for the treatment of OC

  16. Sirt1 deficiency attenuates spermatogenesis and germ cell function.

    Directory of Open Access Journals (Sweden)

    Matthew Coussens

    Full Text Available In mammals, Sirt1, a member of the sirtuin family of proteins, functions as a nicotinamide adenine dinucleotide-dependent protein deactylase, and has important physiological roles, including the regulation of glucose metabolism, cell survival, and mitochondrial respiration. The initial investigations of Sirt1 deficient mice have revealed a phenotype that includes a reduced lifespan, small size, and an increased frequency of abnormal sperm. We have now performed a detailed analysis of the molecular and functional effects of Sirt1 deficiency in the germ line of Sirt1 knock-out (-/- mice. We find that Sirt1 deficiency markedly attenuates spermatogenesis, but not oogenesis. Numbers of mature sperm and spermatogenic precursors, as early as d15.5 of development, are significantly reduced ( approximately 2-10-fold less; P

  17. Disulfiram attenuates osteoclast differentiation in vitro: a potential antiresorptive agent.

    Directory of Open Access Journals (Sweden)

    Hua Ying

    Full Text Available Disulfiram (DSF, a cysteine modifying compound, has long been clinically employed for the treatment of alcohol addiction. Mechanistically, DSF acts as a modulator of MAPK and NF-κB pathways signaling pathways. While these pathways are crucial for osteoclast (OC differentiation, the potential influence of DSF on OC formation and function has not been directly assessed. Here, we explore the pharmacological effects of DSF on OC differentiation, activity and the modulation of osteoclastogenic signaling cascades. We first analyzed cytotoxicity of DSF on bone marrow monocytes isolated from C57BL/6J mice. Upon the establishment of optimal dosage, we conducted osteoclastogenesis and bone resorption assays in the presence or absence of DSF treatment. Luciferase assays in RAW264.7 cells were used to examine the effects of DSF on major transcription factors activation. Western blot, reverse transcription polymerase chain reaction, intracellular acidification and proton influx assays were employed to further dissect the underlying mechanism. DSF treatment dose-dependently inhibited both mouse and human osteoclastogenesis, especially at early stages of differentiation. This inhibition correlated with a decrease in the expression of key osteoclastic marker genes including CtsK, TRAP, DC-STAMP and Atp6v0d2 as well as a reduction in bone resorption in vitro. Suppression of OC differentiation was found to be due, at least in part, to the blockade of several key receptor activators of nuclear factor kappa-B ligand (RANKL-signaling pathways including ERK, NF-κB and NFATc1. On the other hand, DSF failed to suppress intracellular acidification and proton influx in mouse and human osteoclasts using acridine orange quenching and microsome-based proton transport assays. Our findings indicate that DSF attenuates OC differentiation via the collective suppression of several key RANKL-mediated signaling cascades, thus making it an attractive agent for the treatment of OC

  18. Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation

    Science.gov (United States)

    Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T.; Mundell, Stuart J.; Coxon, Carmen H.

    2016-01-01

    Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents. PMID:27716777

  19. Early Astronomy

    Science.gov (United States)

    Thurston, Hugh

    The earliest investigations that can be called scientific are concerned with the sky: they are the beginnings of astronomy. Many early civilizations produced astronomical texts, and several cultures that left no written records left monuments and artifacts-ranging from rock paintings to Stonehenge-that show a clear interest in astronomy. Civilizations in China, Mesopotamia, India and Greece had highly developed astronomies, and the astronomy of the Mayas was by no means negligible. Greek astronomy, as developed by the medieval Arab philosophers, evolved into the astronomy of Copernicus. This displaced the earth from the central stationary position that almost all earlier astronomies had assumed. Soon thereafter, in the first decades of the seventeenth century, Kepler found the true shape of the planetary orbits and Galileo introduced the telescope for astronomical observations.

  20. Live attenuated B. pertussis as a single-dose nasal vaccine against whooping cough.

    Directory of Open Access Journals (Sweden)

    Nathalie Mielcarek

    2006-07-01

    Full Text Available Pertussis is still among the principal causes of death worldwide, and its incidence is increasing even in countries with high vaccine coverage. Although all age groups are susceptible, it is most severe in infants too young to be protected by currently available vaccines. To induce strong protective immunity in neonates, we have developed BPZE1, a live attenuated Bordetella pertussis strain to be given as a single-dose nasal vaccine in early life. BPZE1 was developed by the genetic inactivation or removal of three major toxins. In mice, BPZE1 was highly attenuated, yet able to colonize the respiratory tract and to induce strong protective immunity after a single nasal administration. Protection against B. pertussis was comparable to that induced by two injections of acellular vaccine (aPV in adult mice, but was significantly better than two administrations of aPV in infant mice. Moreover, BPZE1 protected against Bordetella parapertussis infection, whereas aPV did not. BPZE1 is thus an attractive vaccine candidate to protect against whooping cough by nasal, needle-free administration early in life, possibly at birth.

  1. An acoustic eikonal equation for attenuating orthorhombic media

    KAUST Repository

    Hao, Qi

    2017-04-06

    Attenuating orthorhombic models are often used to describe the azimuthal variation of the seismic wave velocity and amplitude in finely layered hydrocarbon reservoirs with vertical fractures. In addition to the P-wave related medium parameters, shear wave parameters are also present in the complex eikonal equation needed to describe the P-wave complex-valued traveltime in an attenuating orthorhombic medium, which increases the complexity of using the P-wave traveltime to invert for the medium parameters in practice. Here, we use the acoustic assumption to derive an acoustic eikonal equation that approximately governs the complex-valued traveltime of P-waves in an attenuating orthorhombic medium. For a homogeneous attenuating orthorhombic media, we solve the eikonal equation using a combination of the perturbation method and Shanks transform. For a horizontal attenuating orthorhombic layer, both the real and imaginary part of the complex-valued reflection traveltime have nonhyperbolic behaviors in terms of the source-receiver offset. Similar to the roles of normal moveout (NMO) velocity and anellipticity, the attenuation NMO velocity and the attenuation anellipticity characterize the variation of the imaginary part of the complex-valued reflection traveltime around zero source-receiver offset.

  2. Rain Attenuation Prediction for Terrestrial Microwave Link in Bangladesh

    Directory of Open Access Journals (Sweden)

    HOSSAIN Sakir

    2014-05-01

    Full Text Available Rain attenuation is a major shortcoming of microwave transmission. As a subtropical country, Bangladesh is one of the highest rainy areas of the world. Thus, designing a terrestrial microwave link is a serious challenge to the engineers. In this paper, the annual rain rate and monthly variation of rate are predicted for different percentage of time of the year from the measured rainfall data. Using ITU rain model for terrestrial microwave communication, the rain attenuation is predicted for five major cities of Bangladesh, namely Dhaka, Chittagong, Rajshahi, Sylhet, and Khulna. It is found that rain attenuation is the most severe in Sylhet and least in Rajshahi. The attenuation is estimated for different frequency and polarization. A horizontally polarized signal encounters 15% more rain attenuation than that of vertically polarized signal. It is also found that attenuation in Rajshahi is about 20% lesser than that in Sylhet. Thus, the horizontally polarized transmission in Rajshahi experiences about 5% less attenuation than the vertically polarized transmission in Sylhet.

  3. Broadband Lg Attenuation Modeling in the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Pasyanos, M E; Matzel, E M; Walter, W R; Rodgers, A J

    2008-08-21

    We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert the amplitude measurements for each frequency independently. In doing so, it appears the frequency-dependence of attenuation is not compatible with the power law representation of Q(f), an assumption that is often made.

  4. Molecular basis of live-attenuated influenza virus.

    Directory of Open Access Journals (Sweden)

    Wen He

    Full Text Available Human influenza is a seasonal disease associated with significant morbidity and mortality. The most effective means for controlling infection and thereby reducing morbidity and mortality is vaccination with a three inactivated influenza virus strains mixture, or by intranasal administration of a group of three different live attenuated influenza vaccine strains. Comparing to the inactivated vaccine, the attenuated live viruses allow better elicitation of a long-lasting and broader immune (humoral and cellular response that represents a naturally occurring transient infection. The cold-adapted (ca influenza A/AA/6/60 (H2N2 (AA ca virus is the backbone for the live attenuated trivalent seasonal influenza vaccine licensed in the United States. Similarly, the influenza A components of live-attenuated vaccines used in Russia have been prepared as reassortants of the cold-adapted (ca H2N2 viruses, A/Leningrad/134/17/57-ca (Len/17 and A/Leningrad/134/47/57-ca (Len/47 along with virulent epidemic strains. However, the mechanism of temperature-sensitive attenuation is largely elusive. To understand how modification at genetic level of influenza virus would result in attenuation of human influenza virus A/PR/8/34 (H1N1,A/PR8, we investigated the involvement of key mutations in the PB1 and/or PB2 genes in attenuation of influenza virus in vitro and in vivo. We have demonstrated that a few of residues in PB1 and PB2 are critical for the phenotypes of live attenuated, temperature sensitive influenza viruses by minigenome assay and real-time PCR. The information of these mutation loci could be used for elucidation of mechanism of temperature-sensitive attenuation and as a new strategy for influenza vaccine development.

  5. Rain attenuation statistics over millimeter wave bands in South Korea

    Science.gov (United States)

    Shrestha, Sujan; Choi, Dong-You

    2017-01-01

    Rain induced degradations are significant for terrestrial microwave links operating at frequencies higher than 10 GHz. Paper presents analyses done on rain attenuation and rainfall data for three years between 2013 till 2015, in 3.2 km experimental link of 38 GHz and 0.1 km link at 75 GHz. The less link distance is maintained for 75 GHz operating frequency in order to have better recording of propagation effect as such attenuation induced by rain. OTT Parsivel is used for collection of rain rate database which show rain rate of about 50 mm/h and attenuation values of 20.89 and 28.55 dB are obtained at 0.01% of the time for vertical polarization under 38 and 75 GHz respectively. Prediction models, namely, ITU-R P. 530-16, Da Silva Mello, Moupfouma, Abdulrahman, Lin and differential equation approach are analyzed. This studies help to identify most suitable rain attenuation model for higher microwave bands. While applying ITU-R P. 530-16, the relative error margin of about 3%, 38% and 42% along with 80, 70, 61% were obtained in 0.1%, 0.01% and 0.001% of the time for vertical polarization under 38 and 75 GHz respectively. Interestingly, ITU-R P. 530-16 shows relatively closer estimation to measured rain attenuation at 75 GHz with relatively less error probabilities and additionally, Abdulrahman and ITU-R P. 530-16 results in better estimation to the measured rain attenuation at 38 GHz link. The performance of prominent rain attenuation models are judged with different error matrices as recommended by ITU-R P. 311-15. Furthermore, the efficacy of frequency scaling technique of rain attenuation between links distribution are also discussed. This study shall be useful for making good considerations in rain attenuation predictions for terrestrial link operating at higher frequencies.

  6. Ultrasonic attenuation measurements determine onset, degree, and completion of recrystallization

    Science.gov (United States)

    Generazio, E. R.

    1988-01-01

    Ultrasonic attenuation was measured for cold worked Nickel 200 samples annealed at increasing temperatures. Localized dislocation density variations, crystalline order and volume percent of recrystallized phase were determined over the anneal temperature range using transmission electron microscopy, X-ray diffraction, and metallurgy. The exponent of the frequency dependence of the attenuation was found to be a key variable relating ultrasonic attenuation to the thermal kinetics of the recrystallization process. Identification of this key variable allows for the ultrasonic determination of onset, degree, and completion of recrystallization.

  7. MNAtoolbox: A Monitored Natural Attenuation Site Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Borns, David J.; Brady, Patrick V.; Brady, Warren D.; Krupka, Kenneth M.; Spalding, Brian P.; Waters, Robert D.; Zhang, Pengchu

    1999-07-12

    Screening of sites for the potential application and reliance upon monitored natural attenuation (MNA) can be done using MNAtoolbox, a web-based tool for estimating extent of biodegradation, chemical transformation, and dilution. MNAtoolbox uses site-specific input data, where available (default parameters are taken from the literature), to roughly quantify the nature and extent of attenuation at a particular site. Use of MNAtoolbox provides 3 important elements of site evaluation: (1) Identifies likely attenuation pathways, (2) Clearly identifies sites where MNA is inappropriate, and (3) Evaluates data requirements for subsequent reliance on MNA as a sole or partial corrective action.

  8. Elemental analysis by means of X-ray attenuation measurements

    Science.gov (United States)

    Cesareo, Roberto; Giannini, Marino

    1980-03-01

    Radioactive sources of 109Cd, 241Am and 57Co were employed to measure the attenuation coefficient of biological materials such as whole blood, red blood cells, plasma, urine, water and of materials of interest for computed tomography, such as plexiglas, polyethylene, nylon, teflon, etc. The experimental errors range between 0.3% and 1%. A method is also presented which allows quantitative analysis of materials by measuring their attenuation coefficient at various monoenergetic X-ray energies. As an example, attenuation measurements at 60 keV and 122 keV were employed in order to determine the concentration of lead and copper in silver alloys.

  9. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  10. Designing attenuators for total-body irradiation using virtual simulation.

    Science.gov (United States)

    Corns, R; Evans, M; Olivares, M; Dyke, L; Podgorsak, E B; Freeman, C R

    2000-01-01

    In total-body photon irradiation, the lungs are the most commonly shielded organ. Lung compensators are often designed by using high-energy portal films. Other organs, such as the kidneys and liver, are poorly visualized in portal films due to their unit-density composition. A computed tomography-based technique to design kidney and liver attenuators involves outlining these organs in a virtual simulation. The position and the shape of the attenuator are then determined from a digitally-reconstructed radiograph. Appropriate attenuator thickness is determined from measured transmission curves. This article provides a summary of this technique for total-body photon irradiation in a 4-MV photon beam.

  11. FSO and radio link attenuation: meteorological models verified by experiment

    Science.gov (United States)

    Brazda, Vladimir; Fiser, Ondrej; Svoboda, Jaroslav

    2011-09-01

    Institute of Atmospheric Physics of Czech Academy measures atmospheric attenuation on 60 m experimental FSO link on 830 and 1550 nm for more than three years. Visibility sensors and two 3D sonic anemometers on both transmitting and receiving site, rain gauge and many sensors enabling the refractivity index computation are spaced along the optical link. Meteorological visibility, wind turbulent energy, sonic temperature, structure index and rain rate are correlated with measured attenuation. FSO link attenuation dependence on the above mentioned parameters is analyzed. The paper shows also basic statistical behavior of the long-term FSO signal level and also the simulation of hybrid link techniques.

  12. The use of microperforated plates to attenuate cavity resonances

    DEFF Research Database (Denmark)

    Fenech, Benjamin; Keith, Graeme; Jacobsen, Finn

    2006-01-01

    The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower...... attenuation that can be obtained in a broad frequency range with the conventional position of the plate. An analytical method for predicting the attenuation is presented. The method involves finding complex eigenvalues and eigenfunctions for the modified cavity and makes it possible to predict Green...

  13. Regulatory inhibition of biological tissue mineralization by calcium phosphate through post-nucleation shielding by fetuin-A

    Science.gov (United States)

    Chang, Joshua C.; Miura, Robert M.

    2016-04-01

    In vertebrates, insufficient availability of calcium and inorganic phosphate ions in extracellular fluids leads to loss of bone density and neuronal hyper-excitability. To counteract this problem, calcium ions are usually present at high concentrations throughout bodily fluids—at concentrations exceeding the saturation point. This condition leads to the opposite situation where unwanted mineral sedimentation may occur. Remarkably, ectopic or out-of-place sedimentation into soft tissues is rare, in spite of the thermodynamic driving factors. This fortunate fact is due to the presence of auto-regulatory proteins that are found in abundance in bodily fluids. Yet, many important inflammatory disorders such as atherosclerosis and osteoarthritis are associated with this undesired calcification. Hence, it is important to gain an understanding of the regulatory process and the conditions under which it can go awry. In this manuscript, we extend mean-field continuum classical nucleation theory of the growth of clusters to encompass surface shielding. We use this formulation to study the regulation of sedimentation of calcium phosphate salts in biological tissues through the mechanism of post-nuclear shielding of nascent mineral particles by binding proteins. We develop a mathematical description of this phenomenon using a countable system of hyperbolic partial differential equations. A critical concentration of regulatory protein is identified as a function of the physical parameters that describe the system.

  14. MASS BALANCE: A KEY TO ADVANCING MONITORED AND ENHANCED ATTENUATION FOR CHLORINATED SOLVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Looney, B; Karen Vangelas, K; Karen-M Adams, K; Francis H. Chappelle; Tom O. Early; Claire H. Sink

    2006-06-30

    Monitored natural attenuation (MNA) and enhanced attenuation (EA) are two environmental management strategies that rely on a variety of attenuation processes to degrade or immobilize contaminants and are implemented at appropriate sites by demonstrating that contaminant plumes have low risk and are stable or shrinking. The concept of a mass balance between the loading and attenuation of contaminants in a groundwater system is a powerful framework for conceptualizing and documenting the relative stability of a contaminant plume. As a result, this concept has significant potential to support appropriate implementation of monitored natural attenuation (MNA) and enhanced attenuation (EA). For mass balance to be useful in engineering practice, however, it is necessary to quantify it in practical ways that facilitate overall site remediation and which are consistent with existing regulatory guidance. Two divergent philosophies exist for quantifying plume stability--empirical and deterministic. The first relies on historical contaminant concentration data and bulk geochemical information from a monitoring well network and documents plume stability using trend analysis and statistical tools. This empirical approach, when feasible, provides powerful and compelling documentation of plume behavior and mass balance. It provides an interpretation on a relevant scale under field conditions. It integrates the operative attenuation processes measured by observing their actual impact on the plume. The power of the empirical approach was recognized early in the development of MNA guidance and protocols and it is currently the basis of the three lines of evidence used in MNA studies. The empirical approach has some weaknesses, however. It requires a relatively long period of undisturbed historical data. Thus it cannot be effectively applied to sites where active remediation was initiated quickly and is currently operating. It cannot be used as a tool to determine how much source

  15. Licking microstructure reveals rapid attenuation of neophobia.

    Science.gov (United States)

    Monk, Kevin J; Rubin, Benjamin D; Keene, Jennifer C; Katz, Donald B

    2014-03-01

    Many animals hesitate when initially consuming a novel food and increase their consumption of that food between the first and second sessions of access-a process termed attenuation of neophobia (AN). AN has received attention as a model of learning and memory; it has been suggested that plasticity resulting from an association of the novel tastant with "safe outcome" results in a change in the neural response to the tastant during the second session, such that consumption increases. Most studies have reported that AN emerges only an hour or more after the end of the first exposure to the tastant, consistent with what is known of learning-related plasticity. But these studies have typically measured consumption, rather than real-time behavior, and thus the possibility exists that a more rapidly developing AN remains to be discovered. Here, we tested this possibility, examining both consumption and individual lick times in a novel variant of a brief-access task (BAT). When quantified in terms of consumption, data from the BAT accorded well with the results of a classic one-bottle task-both revealed neophobia/AN specific to higher concentrations (for instance, 28mM) of saccharin. An analysis of licking microstructure, however, additionally revealed a real-time correlate of neophobia-an explicit tendency, similarly specific for 28-mM saccharin, to cut short the initial bout of licks in a single trial (compared with water). This relative hesitancy (i.e., the shortness of the first lick bout to 28-mM saccharin compared with water) that constitutes neophobia not only disappeared between sessions but also gradually declined in magnitude across session 1. These data demonstrate that the BAT accurately measures AN, and that aspects of AN-and the processes underlying familiarization-begin within minutes of the very first taste.

  16. Attenuation of Landfill Leachate In Unsaturated Sandstone

    Science.gov (United States)

    Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

    Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting

  17. 49 CFR 227.117 - Hearing protector attenuation.

    Science.gov (United States)

    2010-10-01

    ... exposure to an 8-hour TWA of 90 decibels or lower, as required by § 227.115. (c) For employees who have...-weighted average of 85 decibels or lower. (d) The adequacy of hearing protector attenuation shall be...

  18. Psychoneuroendocrine interventions aimed at attenuating immunosenescence: a review

    NARCIS (Netherlands)

    Bauer, M.E.; Muller, G.C.; Correa, B.L.; Vianna, P.; Turner, J.E.; Bosch, J.A.

    2013-01-01

    There is evidence suggesting that immunosenescence can be accelerated by external factors such as chronic stress. Here we review potential psychoneuroendocrine determinants of premature aging of the immune system and discuss available interventions aimed at attenuating immunosenescence. Chronic

  19. MODELING NATURAL ATTENUATION OF FUELS WITH BIOPLUME III

    Science.gov (United States)

    A natural attenuation model that simulates the aerobic and anaerobic biodegradation of fuel hydrocarbons was developed. The resulting model, BIOPLUME III, demonstrates the importance of biodegradation in reducing contaminant concentrations in ground water. In hypothetical simulat...

  20. Biochanin-A attenuates neuropathic pain in diabetic rats

    Directory of Open Access Journals (Sweden)

    Venkateswarlu Chundi

    2016-10-01

    Conclusion: Biochanin-A demonstrated better efficacy in reversing mechanical allodynia than mechanical hyperalgesia. Biochanin-A could be a good drug candidate for further studies to establish the mechanism of attenuation of neuropathic pain.

  1. Psychoneuroendocrine interventions aimed at attenuating immunosenescence: a review

    NARCIS (Netherlands)

    Bauer, M.E.; Muller, G.C.; Correa, B.L.; Vianna, P.; Turner, J.E.; Bosch, J.A.

    2013-01-01

    There is evidence suggesting that immunosenescence can be accelerated by external factors such as chronic stress. Here we review potential psychoneuroendocrine determinants of premature aging of the immune system and discuss available interventions aimed at attenuating immunosenescence. Chronic stre

  2. WAVE ATTENUATION OVER MUD BED: A PSEUDO-PLASTIC MODEL

    Institute of Scientific and Technical Information of China (English)

    Zhang Qing-he; Onyx W.H. Wai; Joseph H. W. Lee

    2003-01-01

    A two-layer model, with the upper layer being the perfect fluid and the lower layer being the pseudo-plastic fluid describing water wave attenuation over mud bed, was established. A simplified method based on the principle of equivalent work was applied to solve the boundary value problems. The computational results of the model show that the two-layer perfect fluid model and the perfect-viscous fluid model are all special cases of the present model. The complex nonlinear properties of wave attenuation over mud bed, can be explained by the present model, e.g., the wave dissipation rate decreases with the wave height in certain cases, while the small wave propagates over mud bed with less energy dissipation and large wave attenuates rapidly in other cases. Other factors influencing the wave attenuation were also discussed.

  3. Earth/Mars Landing Impact Attenuation Using Foam Project

    Data.gov (United States)

    National Aeronautics and Space Administration — On a previous ICA, a test correlated excel based software tool was developed using the innovative Stress?Energy method to better model impact attenuation using...

  4. Dose reduction using a dynamic, piecewise-linear attenuator

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Fleischmann, Dominik [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-02-15

    Purpose: The authors recently proposed a dynamic, prepatient x-ray attenuator capable of producing a piecewise-linear attenuation profile customized to each patient and viewing angle. This attenuator was intended to reduce scatter-to-primary ratio (SPR), dynamic range, and dose by redistributing flux. In this work the authors tested the ability of the attenuator to reduce dose and SPR in simulations. Methods: The authors selected four clinical applications, including routine full field-of-view scans of the thorax and abdomen, and targeted reconstruction tasks for an abdominal aortic aneurysm and the pancreas. Raw data were estimated by forward projection of the image volume datasets. The dynamic attenuator was controlled to reduce dose while maintaining peak variance by solving a convex optimization problem, assuminga priori knowledge of the patient anatomy. In targeted reconstruction tasks, the noise in specific regions was given increased weighting. A system with a standard attenuator (or “bowtie filter”) was used as a reference, and used either convex optimized tube current modulation (TCM) or a standard TCM heuristic. The noise of the scan was determined analytically while the dose was estimated using Monte Carlo simulations. Scatter was also estimated using Monte Carlo simulations. The sensitivity of the dynamic attenuator to patient centering was also examined by shifting the abdomen in 2 cm intervals. Results: Compared to a reference system with optimized TCM, use of the dynamic attenuator reduced dose by about 30% in routine scans and 50% in targeted scans. Compared to the TCM heuristics which are typically used withouta priori knowledge, the dose reduction is about 50% for routine scans. The dynamic attenuator gives the ability to redistribute noise and variance and produces more uniform noise profiles than systems with a conventional bowtie filter. The SPR was also modestly reduced by 10% in the thorax and 24% in the abdomen. Imaging with the dynamic

  5. Human mesenchymal stem cells attenuate early damage in a ventilated pig model of acute lung injury

    Directory of Open Access Journals (Sweden)

    Yuben Moodley

    2016-07-01

    Full Text Available Acute lung injury/acute respiratory distress syndrome (ALI/ARDS is a major cause of global morbidity and mortality. Mesenchymal stem cells (MSC have shown promise in treating inflammatory lung conditions. We hypothesised that human MSC (hMSC can improve ALI/ARDS through their anti-inflammatory actions. We subjected pigs (n = 6 to intravenous oleic acid (OA injury, ventilation and hMSC infusion, while the controls (n = 5 had intravenous OA, ventilation and an infusion vehicle control. hMSC were infused 1 h after the administration of OA. The animals were monitored for additional 4 h. Nuclear translocation of nuclear factor-light chain enhancer of activated B cells (NF-κB, a transcription factor that mediates several inflammatory pathways was reduced in hMSC treated pigs compared to controls (p = 0.04. There was no significant difference in lung injury, assessed by histological scoring in hMSC treated pigs versus controls (p = 0.063. There was no difference in neutrophil counts between hMSC-treated pigs and controls. Within 4 h, there was no difference in the levels of IL-10 and IL-8 pre- and post-treatment with hMSC. In addition, there was no difference in hemodynamics, lung mechanics or arterial blood gases between hMSC treated animals and controls. Subsequent studies are required to determine if the observed decrease in inflammatory transcription factors will translate into improvement in inflammation and in physiological parameters over the long term.

  6. Characterizing X-ray Attenuation of Containerized Cargo

    Energy Technology Data Exchange (ETDEWEB)

    Birrer, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-02

    X-ray inspection systems can be used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, the attenuation characteristics of imported cargo need to be determined. This project focused on developing image processing algorithms for segmenting cargo and using x-ray attenuation to quantify equivalent steel thickness to determine cargo density. These algorithms were applied to over 450 cargo radiographs. The results are summarized in this report.

  7. Impact of Scattering Model on Disdrometer Derived Attenuation Scaling

    Science.gov (United States)

    Zemba, Michael; Luini, Lorenzo; Nessel, James; Riva, Carlo

    2016-01-01

    NASA Glenn Research Center (GRC), the Air Force Research Laboratory (AFRL), and the Politecnico di Milano (POLIMI) are currently entering the third year of a joint propagation study in Milan, Italy utilizing the 20 and 40 GHz beacons of the Alphasat TDP#5 Aldo Paraboni scientific payload. The Ka- and Q-band beacon receivers were installed at the POLIMI campus in June of 2014 and provide direct measurements of signal attenuation at each frequency. Collocated weather instrumentation provides concurrent measurement of atmospheric conditions at the receiver; included among these weather instruments is a Thies Clima Laser Precipitation Monitor (optical disdrometer) which records droplet size distributions (DSD) and droplet velocity distributions (DVD) during precipitation events. This information can be used to derive the specific attenuation at frequencies of interest and thereby scale measured attenuation data from one frequency to another. Given the ability to both predict the 40 gigahertz attenuation from the disdrometer and the 20 gigahertz time-series as well as to directly measure the 40 gigahertz attenuation with the beacon receiver, the Milan terminal is uniquely able to assess these scaling techniques and refine the methods used to infer attenuation from disdrometer data. In order to derive specific attenuation from the DSD, the forward scattering coefficient must be computed. In previous work, this has been done using the Mie scattering model, however, this assumes a spherical droplet shape. The primary goal of this analysis is to assess the impact of the scattering model and droplet shape on disdrometer-derived attenuation predictions by comparing the use of the Mie scattering model to the use of the T-matrix method, which does not assume a spherical droplet. In particular, this paper will investigate the impact of these two scattering approaches on the error of the resulting predictions as well as on the relationship between prediction error and rain rate.

  8. Attenuation of 3CM Microwaves Due to Artificial Rain

    Directory of Open Access Journals (Sweden)

    J. K. Singh

    1966-04-01

    Full Text Available Observations to study the variation of attenuation of 3cm waves due to falling of water or artificial rain are confined to the high rates of precipitation and short distance between the transmitter and receiver, due to low power of the microwave generator. A comparison of these observations and those recorded by others shows that the attenuation increases nonlinearly with the intensity of artificial rainfall which is generally assumed to be linear for the observations at lower rates of precipitation.

  9. Kramers-Kronig relationship between ultrasonic attenuation and phase velocity

    Science.gov (United States)

    Odonnell, M.; Jaynes, E. T.; Miller, J. G.

    1981-01-01

    Kramers-Kronig relations linking the attenuation and dispersion are presented for a linear acoustic system. These expressions are used as a starting point to derive approximate, nearly local expressions relating the ultrasonic attenuation at a specific frequency to the local frequency derivative of the phase velocity (i.e., dispersion). The validity of these approximate relationships is demonstrated in several acoustic systems exhibiting substantially different physical properties.

  10. An analysis of seismic attenuation in random porous media

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The attenuation of seismic wave in rocks has been one of the interesting research topics, but till now no poroelasticity models can thoroughly explain the strong attenuation of wave in rocks. In this paper, a random porous medium model is designed to study the law of wave propagation in complex rocks based on the theory of Biot poroelasticity and the general theory of stochastic process. This model sets the density of grain, porosity, permeability and modulus of frame as random parameters in space, and only one fluid infiltrates in rocks for the sake of better simulation effect in line with real rocks in earth strata. Numerical simulations are implemented. Two different inverse quality factors of fast P-wave are obtained by different methods to assess attenuation through records of virtual detectors in wave field (One is amplitude decay method in time domain and the other is spectral ratio method in frequency domain). Comparing the attenuation results of random porous medium with those of homogeneous porous medium, we conclude that the attenuation of seismic wave of homogeneous porous medium is far weaker than that of random porous medium. In random porous media, the higher heterogeneous level is, the stronger the attenuation becomes, and when heterogeneity σ = 0.15 in simulation, the attenuation result is consistent with that by actual observation. Since the central frequency (50 Hz) of source in numerical simulation is in earthquake band, the numerical results prove that heterogeneous porous structure is one of the important factors causing strong attenuation in real stratum at intermediate and low frequency.

  11. Characterizing Dust Attenuation in Local Star Forming Galaxies

    Science.gov (United States)

    Battisti, Andrew; Calzetti, Daniela; Chary, Ranga-Ram

    2017-01-01

    The dust attenuation for a sample of ~10000 local (z ≤ 0.1) star forming galaxies is constrained as a function of their physical properties. We utilize aperture-matched multi-wavelength data from the UV-to-NIR, available from the Galaxy Evolution Explorer, the Sloan Digital Sky Survey, the United Kingdom Infrared Telescope, and the Two Micron All-Sky Survey, to ensure that regions of comparable size in each galaxy are being analyzed. We characterize the dust attenuation through the slope of the UV flux density and the Balmer decrement (Hα/Hβ). The observed relationship between these quantities is similar to the local starburst relation and is not seen to vary strongly with galactic properties. We derive the total attenuation curve over the range 1250 Å < λ < 28500 Å and find that a single attenuation curve is effective for characterizing the majority of galaxies in our sample. This attenuation curve is slightly lower in the far-UV than local starburst galaxies, by roughly 15%, but appears similar at longer wavelengths and has a normalization of RV = 3.7±0.4 (V-band). This indicates that a single attenuation curve is reasonable for wide application in the local Universe.

  12. Attenuation of Scalar Fluxes Measured with Spatially-displaced Sensors

    Science.gov (United States)

    Horst, T. W.; Lenschow, D. H.

    2009-02-01

    Observations from the Horizontal Array Turbulence Study (HATS) field program are used to examine the attenuation of measured scalar fluxes caused by spatial separation between the vertical velocity and scalar sensors. The HATS data show that flux attenuation for streamwise, crosswind, and vertical sensor displacements are each a function of a dimensionless, stability-dependent parameter n m multiplied by the ratio of sensor displacement to measurement height. The scalar flux decays more rapidly with crosswind displacements than for streamwise displacements and decays more rapidly for stable stratification than for unstable stratification. The cospectral flux attenuation model of Kristensen et al. agrees well with the HATS data for streamwise sensor displacements, although it is necessary to include a neglected quadrature spectrum term to explain the observation that flux attenuation is often less with the scalar sensor downwind of the anemometer than for the opposite configuration. A simpler exponential decay model provides good estimates for crosswind sensor displacements, as well as for streamwise sensor displacements with stable stratification. A model similar to that of Lee and Black correctly predicts flux attenuation for a combination of streamwise and crosswind displacements, i.e. as a function of wind direction relative to the sensor displacement. The HATS data for vertical sensor displacements extend the near-neutral results of Kristensen et al. to diabatic stratification and confirm their finding that flux attenuation is less with the scalar sensor located below the anemometer than if the scalar sensor is displaced an equal distance either horizontally or above the anemometer.

  13. Proteomic Analysis of Pathogenic and Attenuated Alcelaphine Herpesvirus 1▿

    Science.gov (United States)

    Dry, Inga; Haig, David M.; Inglis, Neil F.; Imrie, Lisa; Stewart, James P.; Russell, George C.

    2008-01-01

    The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparations were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and proteins were analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry. Peptides were identified in serial gel slices by using MASCOT software to interrogate virus-specific and nonredundant sequence databases. Twenty-three AlHV-1-encoded proteins and six cellular proteins were identified in the attenuated and virulent viruses. Two polypeptides were detected in only the virulent virus preparations, while one other protein was found in only the attenuated virus. Two of these virus-specific proteins were identified by a single peptide, suggesting that these may be low-abundance virion proteins rather than markers of attenuation or pathogenesis. The results suggest that attenuation of AlHV-1 is not the result of gross changes in the composition of the virus particle but probably due to altered viral gene expression in the infected cell. PMID:18353942

  14. Novel point mutations attenuate autotaxin activity

    Directory of Open Access Journals (Sweden)

    Stracke Mary L

    2009-02-01

    Full Text Available Abstract Background The secreted enzyme autotaxin (ATX stimulates tumor cell migration, tumorigenesis, angiogenesis, and metastasis. ATX hydrolyzes nucleotides, but its hydrolysis of lysophospholipids to produce lysophosphatidic acid (LPA accounts for its biological activities. ATX has been identified only as a constitutively active enzyme, and regulation of its activity is largely unexplored. In spite of its presence in plasma along with abundant putative substrate LPC, the product LPA is found in plasma at unexpectedly low concentrations. It is plausible that the LPA-producing activity of ATX is regulated by its expression and by access to substrate(s. For this reason studying the interaction of enzyme with substrate is paramount to understanding the regulation of LPA production. Results In this study we determine ATX hydrolytic activities toward several artificial and natural substrates. Two novel point mutations near the enzyme active site (H226Q and H434Q confer attenuated activity toward all substrates tested. The Vmax for LPC compounds depends upon chain length and saturation; but this order does not differ among wild type and mutants. However the mutant forms show disproportionately low activity toward two artificial substrates, pNpTMP and FS-3. The mutant forms did not significantly stimulate migration responses at concentrations that produced a maximum response for WT-ATX, but this defect could be rescued by inclusion of exogenous LPC. Conclusion H226Q-ATX and H434Q-ATX are the first point mutations of ATX/NPP2 demonstrated to differentially impair substrate hydrolysis, with hydrolysis of artificial substrates being disproportionately lower than that of LPC. This implies that H226 and H434 are important for substrate interaction. Assays that rely on hydrolyses of artificial substrates (FS-3 and pNpTMP, or that rely on hydrolysis of cell-derived substrate, might fail to detect certain mutated forms of ATX that are nonetheless capable of

  15. Patient position alters attenuation effects in multipinhole cardiac SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn, E-mail: gwells@ottawaheart.ca [Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7 (Canada)

    2015-03-15

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  16. Treatment with recombinant lubricin attenuates osteoarthritis by positive feedback loop between articular cartilage and subchondral bone in ovariectomized rats.

    Science.gov (United States)

    Cui, Zhuang; Xu, Changpeng; Li, Xue; Song, Jinqi; Yu, Bin

    2015-05-01

    Osteoarthritis (OA) is a most commonly multifactorial degenerative joint disease along with the aging population, particularly in postmenopausal women. During the onset of OA, articular cartilage and subchondral bone act in concert as a functional unit. This present study is to investigate the effects of early or late treatment with recombinant lubricin on the onset of osteoarthritis (OA) in ovariectomized (OVX) rats. We found that both early and late recombinant lubricin treatments attenuated the onset of OA by positive feedback loop between articular cartilage and subchondral bone, although late treatment contributed to a lesser effect compared with early treatment. Specifically, treatment with recombinant lubricin protected articular cartilage from degeneration, demonstrated by lower proteoglycan loss, lower OARSI scores, less calcification cartilage zone and reduced immunostaining for collagen X (Col X) and matrix metalloproteinase (MMP-13) but increased the expression of lubricin, in comparison with vehicle-treated OVX rat group. Further, chondroprotective effects of lubricin normalized bone remodeling in subchondral bone underneath. It's suggested that treatment with recombinant lubricin inhibited the elevation of TRAP and Osterix positive cells in OVX rats and led to the normalization of subchondral bone microarchitectures with the suppression of subsidence of bone volume ratio (BV/TV) and trabecular thickness (Tb.Th) and the increase of trabecular separation (Tb.Sp) in vehicle-treated OVX rats. What's more, the normalization of subchondral bone in turn attenuated the articular cartilage erosion by inhibiting vascular invasion from subchondral bone to calcified cartilage zone, exemplified by inhibiting the elevation of CD31 positive cells in calcified cartilage and angiography in subchondral bone. Together, these results shed light that both early and late recombinant lubricin treatments attenuate the onset of OA by balancing the interplay between articular

  17. Imaging the attenuation coefficients of positron beams in matter: positron attenuation tomography

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Charles [Siemens Healthcare, Knoxville, TN (United States)

    2015-05-18

    A new positron annihilation imaging modality is described that enables nondestructive measurement of the linear attenuation coefficients (LACs) of positron beams in heterogeneous materials. This positron attenuation tomography (PAT) technique utilizes a positron emission tomography (PET) system embedded within a uniform static magnetic field, such as is found in integrated PET/MRI scanners. A Ga68-generated positron beam constrained by a 3T magnetic field penetrates objects placed within the scanner. The positrons slow down and annihilate within the object. The resulting annihilation distribution is tomographically imaged by the PET camera. This image may be interpreted as a map of the product of the positron beam's flux and its LAC at each point in the volume. It is shown that under certain easily achieved conditions this image can be decomposed into separate maps of the flux and the LACs, without need for auxiliary measurements. Although these LACs may depend on both beam and material properties, a beam softening correction is demonstrated that effectively removes the dependence on beam variation, leaving a relative LAC that is characteristic of the material. Unlike x-ray, gamma-ray or other transmission techniques, PAT does not require the penetration of the beam entirely through the object. High resolution and high contrast images of positron beam LACs in objects may be produced over nearly the full range of the positron beam, which for Ga68 beta-rays in a 3T field is about 0.5 g/cm{sup 2}. The first examples of PAT images and an initial characterization of performance will be presented.

  18. Role of translation in the UTP-modulated attenuation at the pyrBI operon of Escherichia coli

    DEFF Research Database (Denmark)

    Clemmesen, Kåre; Bonekamp, Fons; Karlström, Olle;

    1985-01-01

    A 273 bp DNA fragment containing the attenuator of the pyrBI operon was inserted into a synthetic cloning site early in the lacZ gene on a plasmid. By this operation the first few codons of lacZ were joined through a linker to the last 39 codons of the open reading frame for the putative pyr...... as for the native pyrB gene. This is probably because the substitution of the normal start of the leader peptide by the start of lacZ alters the coupling between transcription and translation and thereby the attenuation frequency. It cannot, however, be ruled out that the pyrBI operon is regulated at the promoters...

  19. Attenuation correction effects on SPECT/CT procedures: phantoms studies.

    Science.gov (United States)

    Oliveira, M L; Seren, M E G; Rocha, F C; Brunetto, S Q; Ramos, C D; Button, V L S N

    2013-01-01

    Attenuation correction is widely used in SPECT/CT (Single Photon Emission Computed Tomography) procedures, especially for imaging of the thorax region. Different compensation methods have been developed and introduced into clinical practice. Most of them use attenuation maps obtained using transmission scanning systems. However, this gives extra dose of radiation to the patient. The purpose of this study was to identify when attenuation correction is really important during SPECT/CT procedures.For this purpose, we used Jaszczak phantom and phantom with three line sources, filled with technetium ((99m)-Tc), with scattering materials, like air, water and acrylic, in different detectors configurations. In all images acquired were applied analytic and iterative reconstruction algorithms; the last one with or without attenuation correction. We analyzed parameters such as eccentricity, contrast and spatial resolution in the images.The best reconstruction algorithm on average was iterative, for images with 128 × 128 and 64 × 64 matrixes. The analytical algorithm was effective only to improve eccentricity in 64 × 64 matrix and matrix in contrast 128 × 128 with low statistics. Turning to the clinical routine examinations, on average, for 128 × 128 matrix and low statistics counting, the best algorithm was the iterative, without attenuation correction,improving in 150% the three parameters analyzed and, for the same matrix size, but with high statistical counting, iterative algorithm with attenuation correction was 25% better than that without correction. We can conclude that using the iterative algorithm with attenuation correction in the water, and its extra dose given, is not justified for the procedures of low statistic counting, being relevant only if the intention is to prioritize contrast in acquisitions with high statistic counting.

  20. Brunenders: a partially attenuated historic poliovirus type I vaccine strain.

    Science.gov (United States)

    Sanders, Barbara P; Liu, Ying; Brandjes, Alies; van Hoek, Vladimir; de Los Rios Oakes, Isabel; Lewis, John; Wimmer, Eckard; Custers, Jerome H H V; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2015-09-01

    Brunenders, a type I poliovirus (PV) strain, was developed in 1952 by J. F. Enders and colleagues through serial in vitro passaging of the parental Brunhilde strain, and was reported to display partial neuroattenuation in monkeys. This phenotype of attenuation encouraged two vaccine manufacturers to adopt Brunenders as the type I component for their inactivated poliovirus vaccines (IPVs) in the 1950s, although today no licensed IPV vaccine contains Brunenders. Here we confirmed, in a transgenic mouse model, the report of Enders on the reduced neurovirulence of Brunenders. Although dramatically neuroattenuated relative to WT PV strains, Brunenders remains more virulent than the attenuated oral vaccine strain, Sabin 1. Importantly, the neuroattenuation of Brunenders does not affect in vitro growth kinetics and in vitro antigenicity, which were similar to those of Mahoney, the conventional type I IPV vaccine strain. We showed, by full nucleotide sequencing, that Brunhilde and Brunenders differ at 31 nucleotides, eight of which lead to amino acid changes, all located in the capsid. Upon exchanging the Brunenders capsid sequence with that of the Mahoney capsid, WT neurovirulence was regained in vivo, suggesting a role for the capsid mutations in Brunenders attenuation. To date, as polio eradication draws closer, the switch to using attenuated strains for IPV is actively being pursued. Brunenders preceded this novel strategy as a partially attenuated IPV strain, accompanied by decades of successful use in the field. Providing data on the attenuation of Brunenders may be of value in the further construction of attenuated PV strains to support the grand pursuit of the global eradication of poliomyelitis.

  1. Characteristics of coda wave attenuation in Yunnan area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The characteristic of seismic coda wave attenuation in Yunnan area in 7 frequency-bands range from 1 Hz to 20 Hz was estimated by using the local earthquake's waveform data recorded from 22 Yunnan digital seismic stations.Coda attenuation Q-c1 of each station was firstly calculated by single scattering method. Then, mean free path Le and seismic albedo Bo of each station were calculated, and scattering attenuation Q-1s and intrinsic attenuation Q-1i were separated from total attenuation Q-1t by multiple lapse time window analysis based on the multiple scattering model in uniform random isotropic scattering medium. The attenuating characteristics in Yunnan show that most value of Le are in 10~30 km, with maximal within 2~6 Hz;Bo are about 0.5 at 1~2 Hz, but less than 0.5at other frequency-bands, which means Q-1i is comparable with Q-1s at 1~2 Hz, and after 1~2 Hz, Q-1i is greater than Q-1s and dominates the attenuation process. Q-1c is close to Q-1i at other frequency bands except 1~2 Hz.Results show that Q-1 especially Qs-1 varies spatially, Q-1 in eastern Yunnan zone is a bit higher than in northwestern Yunnan zone;northwestern Yunnan zone higher than southwestern Yunnan zone. Comparing with other results in global, Qs-1 in Yunnan is lower than the global average value among these results, Q-1i is higher than the global average value, and Q-1t lies the middle among these results.

  2. Attenuated Neural Processing of Risk in Young Adults at Risk for Stimulant Dependence.

    Directory of Open Access Journals (Sweden)

    Martina Reske

    Full Text Available Approximately 10% of young adults report non-medical use of stimulants (cocaine, amphetamine, methylphenidate, which puts them at risk for the development of dependence. This fMRI study investigates whether subjects at early stages of stimulant use show altered decision making processing.158 occasional stimulants users (OSU and 50 comparison subjects (CS performed a "risky gains" decision making task during which they could select safe options (cash in 20 cents or gamble them for double or nothing in two consecutive gambles (win or lose 40 or 80 cents, "risky decisions". The primary analysis focused on risky versus safe decisions. Three secondary analyses were conducted: First, a robust regression examined the effect of lifetime exposure to stimulants and marijuana; second, subgroups of OSU with >1000 (n = 42, or <50 lifetime marijuana uses (n = 32, were compared to CS with <50 lifetime uses (n = 46 to examine potential marijuana effects; third, brain activation associated with behavioral adjustment following monetary losses was probed.There were no behavioral differences between groups. OSU showed attenuated activation across risky and safe decisions in prefrontal cortex, insula, and dorsal striatum, exhibited lower anterior cingulate cortex (ACC and dorsal striatum activation for risky decisions and greater inferior frontal gyrus activation for safe decisions. Those OSU with relatively more stimulant use showed greater dorsal ACC and posterior insula attenuation. In comparison, greater lifetime marijuana use was associated with less neural differentiation between risky and safe decisions. OSU who chose more safe responses after losses exhibited similarities with CS relative to those preferring risky options.Individuals at risk for the development of stimulant use disorders presented less differentiated neural processing of risky and safe options. Specifically, OSU show attenuated brain response in regions critical for performance monitoring

  3. Attenuation of trace organic compounds (TOrCs) inbioelectrochemical systems

    KAUST Repository

    Werner, Craig M.

    2015-04-01

    Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are two types of microbial bioelectrochemical systems (BESs) that use microorganisms to convert chemical energy in wastewaters into useful energy products such as (bio)electricity (MFC) or hydrogen gas (MEC). These two systems were evaluated for their capacity to attenuate trace organic compounds (TOrCs), commonly found in municipal wastewater, under closed circuit (current generation) and open circuit (no current generation) conditions, using acetate as the carbon source. A biocide was used to evaluate attenuation in terms of biotransformation versus sorption. The difference in attenuation observed before and after addition of the biocide represented biotransformation, while attenuation after addition of a biocide primarily indicated sorption. Attenuation of TOrCs was similar in MFCs and MECs for eight different TOrCs, except for caffeine and trimethoprim where slightly higher attenuation was observed in MECs. Electric current generation did not enhance attenuation of the TOrCs except for caffeine, which showed slightly higher attenuation under closed circuit conditions in both MFCs and MECs. Substantial sorption of the TOrCs occurred to the biofilm-covered electrodes, but no consistent trend could be identified regarding the physico-chemical properties of the TOrCs tested and the extent of sorption. The octanol-water distribution coefficient at pH 7.4 (log DpH 7.4) appeared to be a reasonable predictor for sorption of some of the compounds (carbamazepine, atrazine, tris(2-chloroethyl) phosphate and diphenhydramine) but not for others (N,N-Diethyl-meta-toluamide). Atenolol also showed high levels of sorption despite being the most hydrophilic in the suite of compounds studied (log DpH 7.4=-1.99). Though BESs do not show any inherent advantages over conventional wastewater treatment, with respect to TOrC removal, overall removals in BESs are similar to that reported for conventional wastewater

  4. DEVELOPEMENT OF A LIGHT ATTENUATOR BASED ON GLASSY REFLECTIONS

    Directory of Open Access Journals (Sweden)

    K. Ferria

    2015-07-01

    Full Text Available The light intensity control of a luminous source is a very important operation in many optical applications. Several types of light attenuator exploiting different optical phenomena like diffraction, absorption, and reflection exist and they differ principally in the maximum attenuation rate, the control range, the sensitivity and the spectral band. In the presented work, we have developed and designed a light attenuator based on the progressive decrease of the transmitted light intensity, when it undergoes multiple vitreous reflections across eight plates glasses arranged in a roof shape. Several tests were carried out using a laser light as a source. We have shown that the attenuation rate can be controlled by the choice of the incidence angle on the glasses slides, in addition we have confirmed, for the case of perpendicular polarization of the laser light, that the attenuation obeys to a linear function. The obtained results are very close to those predicted theoretically.

  5. Radar attenuation and temperature within the Greenland Ice Sheet

    Science.gov (United States)

    MacGregor, Joseph A; Li, Jilu; Paden, John D; Catania, Ginny A; Clow, Gary D.; Fahnestock, Mark A; Gogineni, Prasad S.; Grimm, Robert E.; Morlighem, Mathieu; Nandi, Soumyaroop; Seroussi, Helene; Stillman, David E

    2015-01-01

    The flow of ice is temperature-dependent, but direct measurements of englacial temperature are sparse. The dielectric attenuation of radio waves through ice is also temperature-dependent, and radar sounding of ice sheets is sensitive to this attenuation. Here we estimate depth-averaged radar-attenuation rates within the Greenland Ice Sheet from airborne radar-sounding data and its associated radiostratigraphy. Using existing empirical relationships between temperature, chemistry, and radar attenuation, we then infer the depth-averaged englacial temperature. The dated radiostratigraphy permits a correction for the confounding effect of spatially varying ice chemistry. Where radar transects intersect boreholes, radar-inferred temperature is consistently higher than that measured directly. We attribute this discrepancy to the poorly recognized frequency dependence of the radar-attenuation rate and correct for this effect empirically, resulting in a robust relationship between radar-inferred and borehole-measured depth-averaged temperature. Radar-inferred englacial temperature is often lower than modern surface temperature and that of a steady state ice-sheet model, particularly in southern Greenland. This pattern suggests that past changes in surface boundary conditions (temperature and accumulation rate) affect the ice sheet's present temperature structure over a much larger area than previously recognized. This radar-inferred temperature structure provides a new constraint for thermomechanical models of the Greenland Ice Sheet.

  6. Seismic motion attenuation relations in Sichuan and adjacent areas

    Institute of Scientific and Technical Information of China (English)

    LEI Jian-cheng; GAO Meng-tan; YU Yan-xiang

    2007-01-01

    The Sichuan and adjacent areas is divided into southwest China region (SWCR) and Sichuan Basin region (SCBR) according to tectonic backgrounds and seismic damage distribution features. 96 modern destructive earthquakes in SWCR and 40 in SCBR are gathered respectively. All their magnitude parameters are checked. Based on the statistic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The systematic deviations of surface wave magnitude between China seismograph network and U.S. seismograph network are considered in this paper. By making use of the new attenuation relations of bedrock horizontal ground acceleration response spectrum in west U.S., the attenuation relations of bedrock horizontal ground acceleration response spectrum in SWCR and SCBR are digital transformed based on the attenuation model considering acceleration saturation of distance and magnitude in near field.

  7. Wild type measles virus attenuation independent of type I IFN

    Directory of Open Access Journals (Sweden)

    Horvat Branka

    2008-02-01

    Full Text Available Abstract Background Measles virus attenuation has been historically performed by adaptation to cell culture. The current dogma is that attenuated virus strains induce more type I IFN and are more resistant to IFN-induced protection than wild type (wt. Results The adaptation of a measles virus isolate (G954-PBL by 13 passages in Vero cells induced a strong attenuation of this strain in vivo. The adapted virus (G954-V13 differs from its parental strain by only 5 amino acids (4 in P/V/C and 1 in the M gene. While a vaccine strain, Edmonston Zagreb, could replicate equally well in various primate cells, both G954 strains exhibited restriction to the specific cell type used initially for their propagation. Surprisingly, we observed that both G954 strains induced type I IFN, the wt strain inducing even more than the attenuated ones, particularly in human plasmacytoid Dendritic Cells. Type I IFN-induced protection from the infection of both G954 strains depended on the cell type analyzed, being less efficient in the cells used to grow the viral strain. Conclusion Thus, mutations in M and P/V/C proteins can critically affect MV pathogenicity, cellular tropism and lead to virus attenuation without interfering with the α/β IFN system.

  8. Frequency-Dependent Attenuation of Blasting Vibration Waves

    Science.gov (United States)

    Zhou, Junru; Lu, Wenbo; Yan, Peng; Chen, Ming; Wang, Gaohui

    2016-10-01

    The dominant frequency, in addition to the peak particle velocity, is a critical factor for assessing adverse effects of the blasting vibration on surrounding structures; however, it has not been fully considered in blasting design. Therefore, the dominant frequency-dependent attenuation mechanism of blast-induced vibration is investigated in the present research. Starting with blasting vibration induced by a spherical charge propagating in an infinite viscoelastic medium, a modified expression of the vibration amplitude spectrum was derived to reveal the frequency dependency of attenuation. Then, ground vibration induced by more complex and more commonly used cylindrical charge that propagates in a semi-infinite viscoelastic medium was analyzed by numerical simulation. Results demonstrate that the absorptive property of the medium results in the frequency attenuation versus distance, whereas a rapid drop or fluctuation occurs during the attenuation of ground vibration. Fluctuation usually appears at moderate to far field, and the dominant frequency generally decreases to half the original value when rapid drop occurs. The decay rate discrepancy between different frequency components and the multimodal structure of vibration spectrum lead to the unsmooth frequency-dependent attenuation. The above research is verified by two field experiments. Furthermore, according to frequency-based vibration standards, frequency drop and fluctuation should be considered when evaluating blast safety. An optimized piecewise assessment is proposed for more accurate evaluation: With the frequency drop point as the breakpoint, the assessment is divided into two independent sections along the propagating path.

  9. Mid frequency shallow water fine-grained sediment attenuation measurements.

    Science.gov (United States)

    Holland, Charles W; Dosso, Stan E

    2013-07-01

    Attenuation is perhaps the most difficult sediment acoustic property to measure, but arguably one of the most important for predicting passive and active sonar performance. Measurement techniques can be separated into "direct" measurements (e.g., via sediment probes, sediment cores, and laboratory studies on "ideal" sediments) which are typically at high frequencies, O(10(4)-10(5)) Hz, and "indirect" measurements where attenuation is inferred from long-range propagation or reflection data, generally O(10(2)-10(3)) Hz. A frequency gap in measurements exists in the 600-4000 Hz band and also a general acknowledgement that much of the historical measurements on fine-grained sediments have been biased due to a non-negligible silt and sand component. A shallow water measurement technique using long range reverberation is critically explored. An approximate solution derived using energy flux theory shows that the reverberation is very sensitive to depth-integrated attenuation in a fine-grained sediment layer and separable from most other unknown geoacoustic parameters. Simulation using Bayesian methods confirms the theory. Reverberation measurements across a 10 m fine-grained sediment layer yield an attenuation of 0.009 dB/m/kHz with 95% confidence bounds of 0.006-0.013 dB/m/kHz. This is among the lowest values for sediment attenuation reported in shallow water.

  10. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Minicucci, Marcos; Oliveira, Fernando; Santos, Priscila; Polegato, Bertha; Roscani, Meliza; Fernandes, Ana Angelica; Lustosa, Beatriz; Paiva, Sergio; Zornoff, Leonardo; Azevedo, Paula, E-mail: paulasa@fmb.unesp.br [Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP (Brazil)

    2016-05-15

    Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

  11. Transluminal Attenuation Gradient for Thrombotic Risk Assessment in Kawasaki Disease Patients with Coronary Artery Aneurysms

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Burns, Jane; Marsden, Alison

    2014-11-01

    Kawasaki Disease (KD) can result in coronary aneurysms in up to 25% of patients if not treated early putting patients at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines for administering anti-coagulation therapy currently rely on anatomy alone. Previous studies including patient specific modeling and computer simulations in KD patients have suggested that hemodynamic data can predict regions susceptible to thrombus formation. In particular, high Particle Residence Time gradient (PRTg) regions have shown to correlate with regions of thrombus formation. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length. TAG has been used for characterizing coronary artery stenoses, however this approach has not yet been used in aneurysmal vessels. The aim of this study is to analyze the correlation between TAG and PRTg in KD patients with aneurysms and evaluate the use of TAG as an index to quantify thrombotic risk. Patient specific anatomic models for fluids simulations were constructed from CT angiographic image data from 3 KD aneurysm patients and one normal control. TAG values for the aneurysm patients were markedly lower than for the non-aneurysmal patient (mean -18.38 vs. -2). In addition, TAG values were compared to PRTg obtained for each patient. Thrombotic risk stratification for KD aneurysms may be improved by incorporating TAG and should be evaluated in future prospective studies.

  12. In Vitro intestinal mucosal epithelial responses to wild-typeSalmonella Typhi and attenuated typhoid vaccines

    Directory of Open Access Journals (Sweden)

    Maria eFiorentino

    2013-02-01

    Full Text Available Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S. Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4h post-exposure. S. Typhi triggered the secretion of interleukin (IL-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

  13. Geniposide attenuates mitochondrial dysfunction and memory deficits in APP/PS1 transgenic mice.

    Science.gov (United States)

    Lv, Cui; Liu, Xiaoli; Liu, Hongjuan; Chen, Tong; Zhang, Wensheng

    2014-01-01

    Oxidative stress and mitochondrial dysfunction appear early and contribute to the disease progression in Alzheimer's disease (AD), which can be detected extensively in AD patients brains as well as in transgenic AD mice brains. Thus, treatments that result in attenuation of oxidative stress and mitochondrial dysfunction may hold potential for AD treatment. Geniposide, a pharmacologically active component purified from gardenia fruit, exhibits anti-oxidative, antiinflammatory and other important therapeutic properties. However, whether geniposide has any protective effect on oxidative stress and mitochondrial dysfunction in AD transgenic mouse model has not yet been reported. Here, we demonstrate that intragastric administration of geniposide significantly reduces oxidative stress and mitochondrial dysfunction in addition to improving learning and memory in APP/PS1 mice. Geniposide exerts protective effects on mitochondrial dysfunction in APP/PS1 mice through suppressing the mitochondrial oxidative damage and increasing the mitochondrial membrane potential and activity of cytochrome c oxidase. These studies indicate that geniposide may attenuate memory deficits through the suppression of mitochondrial oxidative stress. Thus, geniposide may be a potential therapeutic reagent for halting and preventing AD progress.

  14. Edaravone attenuates monocyte adhesion to endothelial cells induced by oxidized low-density lipoprotein

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijuan, E-mail: zjlee038@163.com; Cheng, Jianxin; Wang, Liping

    2015-10-30

    Oxidized low-density lipoprotein (oxLDL) plays a vital role in recruitment of monocytes to endothelial cells, which is important during early stages of atherosclerosis development. Edaravone, a potent and novel scavenger of free radicals inhibiting hydroxyl radicals, has been clinically used to reduce the neuronal damage following ischemic stroke. In the present study, Edaravone was revealed to markedly reduce oxLDL-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). The inhibitory mechanism of Edaravone was associated with suppression of the chemokine MCP-1 and adhesion molecule VCAM-1 and ICAM-1 expression. In addition, luciferase reporter assay results revealed that administration of Edaravone attenuated the increase in NF-κB transcriptional activity induced by oxLDL. Notably, it's also shown that Edaravone treatment blocked oxLDL induced p65 nuclear translocation in HUVECs. Results indicate that Edaravone negatively regulates endothelial inflammation. - Highlights: • Edaravone reduces oxLDL-induced monocyte adhesion to HUVECs. • Edaravone attenuates oxLDL-induced expression of MCP-1, VCAM-1, and ICAM-1. • Edaravone reduces NF-κB transcriptional activity and p65 nuclear translocation.

  15. Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs.

    Science.gov (United States)

    Muñoz-González, Sara; Perez-Simó, Marta; Muñoz, Marta; Bohorquez, José Alejandro; Rosell, Rosa; Summerfield, Artur; Domingo, Mariano; Ruggli, Nicolas; Ganges, Llilianne

    2015-07-09

    Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.

  16. Amniotic fluid stem cells from EGFP transgenic mice attenuate hyperoxia-induced acute lung injury.

    Directory of Open Access Journals (Sweden)

    Shih-Tao Wen

    Full Text Available High concentrations of oxygen aggravate the severity of lung injury in patients requiring mechanical ventilation. Although mesenchymal stem cells have been shown to effectively attenuate various injured tissues, there is limited information regarding a role for amniotic fluid stem cells (AFSCs in treating acute lung injury. We hypothesized that intravenous delivery of AFSCs would attenuate lung injury in an experimental model of hyperoxia-induced lung injury. AFSCs were isolated from EGFP transgenic mice. The in vitro differentiation, surface markers, and migration of the AFSCs were assessed by specific staining, flow cytometry, and a co-culture system, respectively. The in vivo therapeutic potential of AFSCs was evaluated in a model of acute hyperoxia-induced lung injury in mice. The administration of AFSCs significantly reduced the hyperoxia-induced pulmonary inflammation, as reflected by significant reductions in lung wet/dry ratio, neutrophil counts, and the level of apoptosis, as well as reducing the levels of inflammatory cytokine (IL-1β, IL-6, and TNF-α and early-stage fibrosis in lung tissues. Moreover, EGFP-expressing AFSCs were detected and engrafted into a peripheral lung epithelial cell lineage by fluorescence microscopy and DAPI stain. Intravenous administration of AFSCs may offer a new therapeutic strategy for acute lung injury (ALI, for which efficient treatments are currently unavailable.

  17. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design

    Energy Technology Data Exchange (ETDEWEB)

    Yamshchikov, Vladimir, E-mail: yaximik@gmail.com; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-15

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E{sub 138}K and K{sub 279}M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use. - Highlights: • Further attenuation of a WN vaccine precursor is outlined. • Effect of SA14-14-2 attenuating mutations is tested. • Mechanism of attenuation is proposed and illustrated. • The need for additional attenuating mutations is justified.

  18. Ultrasonic attenuation of CdSe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, B.J., E-mail: braulio@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Calderon, E.; Bracho, D.B. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Perez, J.F. [Laboratorio de Instrumentacion Cientifica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of)

    2010-08-01

    The ultrasonic attenuation of a single crystal of CdSe has been investigated over the temperature range from 1.2 to 300 K at frequencies of 10, 30 and 90 MHz. We report here the temperature dependence of the attenuation in the range 1.2-30 K for piezoactive and non-piezoactive acoustic waves. A temperature-induced relaxation for two piezoactive waves, which scale with frequency towards higher temperatures, was found. A modified Hutson and White model with a new parameter {gamma} is proposed to explain the relaxation maxima of our data and others in the literature. In this model the parameter {gamma}, which seems to be closely related to the compensation, takes into account the impurities-sound wave piezoelectric coupling. By inverting the proposed expression for the sound attenuation to obtain the electrical conductivity from the relaxation, it is found that impurity conductivity of the hopping type is the dominant conduction process at low temperatures.

  19. Correction for hydrometeor attenuation of C band radar data

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    C band digital weather radar observed data, collected from the Huaihe River Basin Energy and Water Cycle Experiment (HUBEX), are used for the study of correction of hydrometeor attenuation in the Fuyang region. An iterative algorithm is used for the correction scheme. The preliminary study shows that there may be a big difference between the radar observed reflectivity and the corresponding corrected one. Based upon the hourly precipitation data derived by the radar data sampled from the observations at intervals of 10 min and rain-gauge-recorded hourly precipitation data, it is found that the attenuation correction algorithm gives better results than those from the direct observation. It is also shown that the temperature of hydrometeors may strongly affect the results derived from the attenuation algorithm.

  20. Broadband fractal acoustic metamaterials for low-frequency sound attenuation

    Science.gov (United States)

    Song, Gang Yong; Cheng, Qiang; Huang, Bei; Dong, Hui Yuan; Cui, Tie Jun

    2016-09-01

    We fabricate and experimentally characterize a broadband fractal acoustic metamaterial that can serve to attenuate the low-frequency sounds at selective frequencies ranging from 225 to 1175 Hz. The proposed metamaterials are constructed by the periodic Hilbert fractal elements made of photosensitive resin via 3D printing. In analogy to electromagnetic fractal structures, it is shown that multiple resonances can also be excited in the acoustic counterpart due to their self-similar properties, which help to attenuate the acoustic energy in a wide spectrum. The confinement of sound waves in such subwavelength element is evidenced by both numerical and experimental results. The proposed metamaterial may provide possible alternative for various applications such as the noise attenuation and the anechoic materials.

  1. Random noise attenuation using an improved anisotropic total variation regularization

    Science.gov (United States)

    Gemechu, Diriba; Yuan, Huan; Ma, Jianwei

    2017-09-01

    In seismic data processing, attenuation of random noise from the observed data is the basic step which improves the signal-to-noise ratio (SNR) of seismic data. In this paper, we proposed an anisotropic total bounded variation regularization approach to attenuate noise. An improved constraint convex optimization model is formulated for this approach and then the split Bregman algorithm is used to solve the optimization model. Generalized cross validation (GCV) technique is used to estimate the regularization parameter. Synthetic and real seismic data are considered to show the out performance of the proposed method in terms of event-preserving denoising, in comparison with FX deconvolution, shearlet hard thresholding, and anisotropic total variation methods. The numerical results indicate that the proposed method effectively attenuates random noise by preserving the structure and important features of seismic data.

  2. Consideration of natural attenuation. In remedation contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-04-15

    Upon the proposal submitted by ist Standing committee 5 (Contaminated Sites Committee - ALA) the Federal / State Working Group on Soil protection employed an ad hoc subcommittee dealing with considering natural attenuation in remediating contaminated sites and preparing an inter-State position paper. In the present position paper the way how to consider natural attenuation in practical remediation of contaminated sites is described. The systematic approach outlined allows an understandable decision-finding. A way is shown how the competent soil protection authorities may exercise discretion and in the framework of checking the appropriateness of measures may decide on the implementation of MNA based on a MNA concept (MNA = monitored natural attenuation). It is, however, also explained that when carrying out MNA a decision always made in an individual case is concerned which should be made in a close agreement between the obligated party and the authority.

  3. Monte Carlo simulation of laser attenuation characteristics in fog

    Science.gov (United States)

    Wang, Hong-Xia; Sun, Chao; Zhu, You-zhang; Sun, Hong-hui; Li, Pan-shi

    2011-06-01

    Based on the Mie scattering theory and the gamma size distribution model, the scattering extinction parameter of spherical fog-drop is calculated. For the transmission attenuation of the laser in the fog, a Monte Carlo simulation model is established, and the impact of attenuation ratio on visibility and field angle is computed and analysed using the program developed by MATLAB language. The results of the Monte Carlo method in this paper are compared with the results of single scattering method. The results show that the influence of multiple scattering need to be considered when the visibility is low, and single scattering calculations have larger errors. The phenomenon of multiple scattering can be interpreted more better when the Monte Carlo is used to calculate the attenuation ratio of the laser transmitting in the fog.

  4. Measurement of acoustic attenuation in South Pole ice

    Science.gov (United States)

    IceCube Collaboration; Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Gustafsson, L.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; IceCube Collaboration

    2011-01-01

    Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient α = 3.20 ± 0.57 km-1 between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for λ ≡ 1/α of ˜300 m with 20% uncertainty. No significant depth or frequency dependence has been found.

  5. Reduced Protein Expression in a Virus Attenuated by Codon Deoptimization

    Directory of Open Access Journals (Sweden)

    Benjamin R. Jack

    2017-09-01

    Full Text Available A general means of viral attenuation involves the extensive recoding of synonymous codons in the viral genome. The mechanistic underpinnings of this approach remain unclear, however. Using quantitative proteomics and RNA sequencing, we explore the molecular basis of attenuation in a strain of bacteriophage T7 whose major capsid gene was engineered to carry 182 suboptimal codons. We do not detect transcriptional effects from recoding. Proteomic observations reveal that translation is halved for the recoded major capsid gene, and a more modest reduction applies to several coexpressed downstream genes. We observe no changes in protein abundances of other coexpressed genes that are encoded upstream. Viral burst size, like capsid protein abundance, is also decreased by half. Together, these observations suggest that, in this virus, reduced translation of an essential polycistronic transcript and diminished virion assembly form the molecular basis of attenuation.

  6. Fiber movements and sound attenuation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1999-01-01

    Propagation of a plane harmonic sound wave in fiber materials such as glass wool is studied theoretically and experimentally. Wave equations are set up that take into account the movement of the fiber skeleton. The attenuation of the sound wave in slabs of glass wool was calculated and measured....... The main new result is that the experimental attenuation at low-frequency propagating wave is lower when the fibers move. For wave with frequency 100 Hz in glass wool of density 20 kg/m3, the attenuation of a layer of thickness 0.20 m is 4 dB if the fibers move, and 12 dB if they do not move...

  7. Smart structures for shock wave attenuation using ER inserts

    Science.gov (United States)

    Kim, Jaehwan; Kim, Jung-Yup; Choi, Seung-Bok; Kim, Kyung-Su

    2001-08-01

    This Paper demonstrates the possibility of shock wave attenuation propagating through a smart structure that incorporates ER insert. The wave transmission of ER inserted beam is theoretically derived using Mead & Markus model and the theoretical results are compared with the finite element analysis results. To experimentally verify the shock wave attenuation, ER insert in an aluminum plate is made and two piezoceramic disks are used as transmitter and receiver of the wave. The transmitter sends a sine pulse signal such that a component of shock wave travels through the plate structure and the receiver gets the transmitted wave signal. Wave propagation of the ER insert can be adjusted by changing the applied electric field on the ER insert. Details of the experiment are addressed and the possibility of shock wave attenuation is experimentally verified. This kind of smart structure can be used for warship and submarine hull structures to protect fragile and important equipment.

  8. Long term attenuation measurements on optical ground wires

    Energy Technology Data Exchange (ETDEWEB)

    Lamarche, L.; Gagnon, D.; Miron, M. [Hydro-Quebec, Varennes, Quebec1 (Canada)

    1996-11-01

    The attenuation stability of optical fibers integrated in optical ground wires (OPGW) cables over temperature and time is of paramount importance in the planning of long distance links. The authors report here a mean thermal attenuation dependence of 5.5{center_dot}10{sup {minus}5} dB/(km{center_dot}C) at 1,550 nm, on a 220 km span of dispersion shifted (DS) fibers of an installed OPGW cable. This optical link is installed in the James Bay region over a 735 kV power line where temperature varies from {minus}40 C to +30 C annually. The data sample presented covers 1.5 year starting December 1993. The data sample presented covers 1.5 year starting December 1993. During that period, the authors also observed a temporal evolution of the attenuation described by the empirical relation A = A{sub 0} (t{minus}t{sub 0}){sup 0.00394}.

  9. Mild hypothermia alleviates brain oedema and blood-brain barrier disruption by attenuating tight junction and adherens junction breakdown in a swine model of cardiopulmonary resuscitation

    Science.gov (United States)

    Li, Jiebin; Li, Chunsheng; Yuan, Wei; Wu, Junyuan; Li, Jie; Li, Zhenhua; Zhao, Yongzhen

    2017-01-01

    Mild hypothermia improves survival and neurological recovery after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). However, the mechanism underlying this phenomenon is not fully elucidated. The aim of this study was to determine whether mild hypothermia alleviates early blood–brain barrier (BBB) disruption. We investigated the effects of mild hypothermia on neurologic outcome, survival rate, brain water content, BBB permeability and changes in tight junctions (TJs) and adherens junctions (AJs) after CA and CPR. Pigs were subjected to 8 min of untreated ventricular fibrillation followed by CPR. Mild hypothermia (33°C) was intravascularly induced and maintained at this temperature for 12 h, followed by active rewarming. Mild hypothermia significantly reduced cortical water content, decreased BBB permeability and attenuated TJ ultrastructural and basement membrane breakdown in brain cortical microvessels. Mild hypothermia also attenuated the CPR-induced decreases in TJ (occludin, claudin-5, ZO-1) and AJ (VE-cadherin) protein and mRNA expression. Furthermore, mild hypothermia decreased the CA- and CPR-induced increases in matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) expression and increased angiogenin-1 (Ang-1) expression. Our findings suggest that mild hypothermia attenuates the CA- and resuscitation-induced early brain oedema and BBB disruption, and this improvement might be at least partially associated with attenuation of the breakdown of TJ and AJ, suppression of MMP-9 and VEGF expression, and upregulation of Ang-1 expression. PMID:28355299

  10. Continental Fog Attenuation Empirical Relationship from Measured Visibility Data

    Directory of Open Access Journals (Sweden)

    F. Nadeem

    2010-12-01

    Full Text Available Free Space Optics (FSO has the great potential for future communication applications. However, weather influenced reduced availability had been the main cause for its restricted growth. Among different weather influences fog plays the major role. A new model generalized for all FSO wavelengths, has been proposed for the prediction of continental fog attenuation using visibility data. The performance of the proposed model has been compared with well known models for measured attenuation data of Continental fog. The comparison has been performed in terms of Root Mean Square Error (RMSE.

  11. Homogeneous Magnetic Field Source For Attenuated Total Reflection

    Directory of Open Access Journals (Sweden)

    Lesňák Michal

    2014-07-01

    Full Text Available The paper is focused on the study of two-dimensional magnetic field distribution used for an analysis of samples containing magnetically active films by means of the Attenuated Total Reflection (ATR method. The design of a proposed electromagnet and the magnetic field model computation are presented together with the results obtained from magnetic field distribution measurement. The ATR method can provide information about a thin film thickness, refractive index, and attenuation in addition to the perfunctory coupling of an optical wave into and off a waveguide [1, 2]. The prism coupling conditions are determined for magnetic structures with induced anisotropy.

  12. Sound attenuation using microelectromechanical systems fabricated acoustic metamaterials

    Science.gov (United States)

    Yunker, William N.; Stevens, Colin B.; Flowers, George T.; Dean, Robert N.

    2013-01-01

    Unlike traditional rotational gyroscopes, microelectromechanical systems (MEMS) gyroscopes use a vibrating proof mass rather than a rotational mass to sense changes in angular rate. They are also smaller and less expensive than traditional gyroscopes. MEMS gyroscopes are known to be susceptible to the effects of acoustic noise, in particular high frequency and high power acoustic noise. Most notably, this has been proven true in aerospace applications where the noise can reach levels in excess of 120 dB and the noise frequency can exceed 20 kHz. The typical resonant frequency for the proof mass of a MEMS gyroscope is between 3 and 20 kHz. High power, high frequency acoustic noise can disrupt the output signal of the gyroscope to the point that the output becomes unreliable. In recent years, considerable research has focused on the fascinating properties found in metamaterials. A metamaterial is an artificially fabricated device or structure that is engineered to produce desired material responses that can either mimic known behaviors or produce responses that do not occur naturally in materials found in nature. Acoustic metamaterials, in particular, have shown great promise in the field of sound attenuation. This paper proposes a method to mitigate the performance degradation of the MEMS gyroscope in the presence of high power, high frequency acoustic noise by using a new acoustic metamaterial in the form of a two-dimensional array of micromachined Helmholtz resonators. The Helmholtz resonators are fabricated in a silicon wafer using standard MEMS manufacturing techniques and are designed to attenuate sound at the resonant frequency of the gyroscope proof mass. The resonator arrays were diced from the silicon wafer in one inch squares and assembled into a box open on one end in a manner to attenuate sound on all sides of the gyroscope, and to seal the gyroscope inside the box. The resulting acoustic metamaterial device was evaluated in an acoustic chamber and was

  13. Quasi-optical attenuators for ALMA band 10 receiver

    Science.gov (United States)

    Gonzalez, A.; Fujii, Y.; Kaneko, K.; Uzawa, Y.

    2011-12-01

    Simple quasi-optical attenuators based on beam truncation have been designed, fabricated and tried on ALMA band 10 receivers (787-950 GHz) with optimal results. The design is based on physical-optics simulations considering effects of diffraction. The use of these attenuators allows flexibility in the design of the local oscillator (LO) quasi-optical injection scheme depending on the specific performance of components for each of the 73 ALMA band 10 receivers. In particular, they have proven very effective to keep system noise within the stringent ALMA requirements (230 K at 80% of 787-950 GHz band).

  14. Attenuating water hammer pressure by means of gas storage tank

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The basic equations for computing the volume of gas storage tank were derived from the principles of attenuating water hammer pressure. Verifications using experiments indicate that the proposed equation can provide a fare precision in the predictions. By using the model of solid-liquid two-phase flow, the gas storage tank, pressure-relief valves and slow-closure reverse-control valves were compared with practical engineering problems, and the functions of gas storage tank in attenuating water hammer pressure were further investigated.

  15. Simultaneous amplification and attenuation in isotropic chiral materials

    Science.gov (United States)

    Mackay, Tom G.; Lakhtakia, Akhlesh

    2016-05-01

    The electromagnetic field phasors in an isotropic chiral material (ICM) are superpositions of two Beltrami fields of different handedness. Application of the Bruggeman homogenization formalism to two-component composite materials delivers ICMs wherein Beltrami fields of one handedness attenuate whereas Beltrami fields of the other handedness amplify. One component material is a dissipative ICM, the other an active dielectric material. The range of the volume fraction of the active component material for which simultaneous amplification and attenuation is exhibited decreases—but does not vanish—as the ICM component becomes more dissipative and as its chirality parameter reduces in magnitude.

  16. Heat radiative characteristics of ultra-attenuated materials

    Institute of Scientific and Technical Information of China (English)

    Dehong Xia; Yonghong Wu

    2004-01-01

    From the microstructure of heat radiation, the interaction between the incident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal the emission, absorption, transmission and reflection mechanisms of the incident heat radiative wave in materials. Based on Lorentz dispersion theory, the effect of optical parameters on heat radiative characteristics is also analyzed. The method of ultra-attenuation and nanocrystallization improving the heat radiative characteristics of the material and the emissivity dispersion of the ultra-attenuated materials are brought to light.

  17. Regularized Image Reconstruction for Ultrasound Attenuation Transmission Tomography

    Directory of Open Access Journals (Sweden)

    I. Peterlik

    2008-06-01

    Full Text Available The paper is focused on ultrasonic transmission tomography as a potential medical imaging modality, namely for breast cancer diagnosis. Ultrasound attenuation coefficient is one of the tissue parameters which are related to the pathological tissue state. A technique to reconstruct images of attenuation distribution is presented. Furthermore, an alternative to the commonly used filtered backprojection or algebraic reconstruction techniques is proposed. It is based on regularization of the image reconstruction problem which imposes smoothness in the resulting images while preserving edges. The approach is analyzed on synthetic data sets. The results show that it stabilizes the image restoration by compensating for main sources of estimation errors in this imaging modality.

  18. Research on attenuation characteristic of sound wave in coal or rock body

    Institute of Scientific and Technical Information of China (English)

    NIE Bai-sheng; HE Xue-qiu; LI Xiang-chun; GAO Hong

    2007-01-01

    In order to using power sound wave increase permeability of coal, rules of attenuation of sound wave in coal should be studied. In this paper, characteristic and mechanism of attenuation of sound wave in coal was researched according to acoustic theory and attenuation coefficients was estimated by acoustic parameter of coal. The research results show that the main attenuation mechanism of sound wave in coal is absorption attenuation and scattering attenuation. The absorption attenuation includes viscous absorption, thermal conduction absorption and relaxation absorption. Attenuation coefficient of sound wave in gaseous coal is 38.5 Np/m. Researches on attenuation characteristic of sound wave will provide the theoretical basis for power sound wave improving permeability of coal and accelerating desorption of coal bed gas.

  19. Comparison of dexmedetomidine and lignocaine on attenuation of airway and pressor responses during tracheal extubation

    Directory of Open Access Journals (Sweden)

    Vivek Bharti Sharma

    2014-01-01

    Full Text Available Background: Haemodynamic stability and rapid emergence after general anaesthesia used in spinal surgery is a common practice, the goal of which is to permit early neurological motor and sensory examination. Extubation is almost always associated with hypertension, increased airway response and arrhythmias. We have compared the effects of the α-2 agonist Dexmedetomidine and Lignocaine given at the end of the procedure on attenuation of airway and pressor responses following tracheal extubation. This study is a randomised, placebo-controlled, double-blinded study. Materials and Methods: Sixty ASA I-III patients, aged 18-70 years, scheduled to undergo spinal surgery at the level of thoracic, lumbar or sacral region were randomly divided into three groups. Balanced general anaesthesia comprising standard procedures and drugs were used for monitoring, induction and maintenance. At the last skin suture, inhalation anaesthetic was discontinued. After turning the patient supine and return of spontaneous efforts, in Group D Dexmedetomidine 0.5 μg/kg, in Group L Lignocaine 1.5 mg/kg and in Group P normal saline (10 ml were administered as bolus intravenously over 60 seconds. Systolic, diastolic and mean arterial pressures and heart rate were recorded before intravenous administration and also every minute for 3 minutes, at 5, 10 and 15 minutes post-extubation. Duration of emergence and extubation were noted and attenuation of airway response and quality of extubation was evaluated on cough grading. Results: Mean arterial pressures and heart rate were higher in Group L and Group P than in Group D but not statistically significant. The duration of emergence, extubation and recovery were comparable in all the groups (P > 0.05. Extubation Quality Scores was 1 in 80%, 2 in 20% in Group D; in Group L, the quality scores were 1 for 55%, 2 for 45% and I Group P 1 for 35%, 2 for 45% and 3 for 20% of the patients. The requirement of rescue analgesia was also less

  20. The Ultraviolet Attenuation Law in Backlit Spiral Galaxies

    CERN Document Server

    Keel, William C; Holwerda, Benne W; Lintott, Chris J; Schawinski, Kevin

    2014-01-01

    (Abridged) The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use GALEX, XMM Optical Monitor, and HST data to explore the UV attenuation in the outer parts of spiral disks which are backlit by other UV-bright galaxies, starting with candidates provided by Galaxy Zoo participants. Our analysis incorporates galaxy symmetry, using non-overlapping regions of each galaxy to derive error estimates on the attenuation measurements. The entire sample has an attenuation law close to the Calzetti et al. (1994) form; the UV slope for the overall sample is substantially shallower than found by Wild et al. (2011), a reasonable match to the more distant galaxies in our sample but not to the weighted combination including NGC 2207. The nearby, bright spiral NGC 2207 alone gives accuracy almost equal ...

  1. Body Wave Crustal Attenuation Characteristics in the Garhwal Himalaya, India

    Science.gov (United States)

    Negi, Sanjay S.; Paul, Ajay; Joshi, Anand; Kamal

    2015-06-01

    We estimate frequency-dependent attenuation of P and S waves in Garhwal Himalaya using the extended coda normalization method for the central frequencies 1.5, 2, 3, 4, 6, 8, 10, 12, and 16 Hz, with earthquake hypocentral distance ranging from 27 to 200 km. Forty well-located local earthquake waveforms were used to study the seismic attenuation characteristics of the Garhwal Himalaya, India, as recorded by eight stations operated by Wadia Institute of Himalayan Geology, Dehradun, India, from 2007 to 2012. We find frequency-dependent P and S wave quality factors as defined by the relations Q P = 56 ± 8 f 0.91±0.002 and Q S = 151 ± 8 f 0.84±0.002 by fitting a power-law frequency dependence model for the estimated values over the whole region. Both the Q P and Q S values indicate strong attenuation in the crust of Garhwal Himalaya. The ratio of Q S/ Q P > 1 obtained for the entire analyzed frequency range suggests that the scattering loss is due to a random and high degree of heterogeneities in the earth medium, playing an important role in seismic wave attenuation in the Himalayan crust.

  2. Bioavailability of jarosite for stimulating acid mine drainage attenuation

    Science.gov (United States)

    Coggon, Matthew; Becerra, Caryl Ann; Nüsslein, Klaus; Miller, Karen; Yuretich, Richard; Ergas, Sarina J.

    2012-02-01

    Biological reduction of iron-sulfate minerals, such as jarosite, has the potential to contribute to the natural attenuation of acid mine drainage (AMD) sites. Previous studies of AMD attenuation at Davis Mine, an abandoned pyrite mine in Rowe Massachusetts, provided evidence of iron and sulfate reduction by indigenous bacteria. Jarosite is a large component of the sediment at Davis Mine and may play a role in AMD attenuation. In this study, microcosms were constructed with groundwater and sediment from Davis Mine and amended with glycerol, nitrogen and phosphorus (GNP) and naturally formed natrojarosite. Over time, higher total iron, sulfate, pH and sodium concentrations and lower oxidation-reduction potentials were observed in microcosms amended with GNP and jarosite, compared with unamended microcosms and killed controls. Geochemical modeling predicted jarosite precipitation under microcosm conditions, suggesting that abiotic processes were unlikely contributors to jarosite dissolution. SEM imaging at the jarosite surface showed microbial attachment. Microbial community composition analysis revealed a shift to higher populations of Clostridia, which are known to reduce both iron and sulfate. The results show that jarosite may be utilized as an electron acceptor by iron and/or sulfate reducing bacteria at Davis Mine and its presence may aid in the attenuation of AMD.

  3. Outdoor FSO Communications Under Fog: Attenuation Modeling and Performance Evaluation

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-18

    Fog is considered to be a primary challenge for free space optics (FSO) systems. It may cause attenuation that is up to hundreds of decibels per kilometer. Hence, accurate modeling of fog attenuation will help telecommunication operators to engineer and appropriately manage their networks. In this paper, we examine fog measurement data coming from several locations in Europe and the United States and derive a unified channel attenuation model. Compared with existing attenuation models, our proposed model achieves a minimum of 9 dB, which is lower than the average root-mean-square error (RMSE). Moreover, we have investigated the statistical behavior of the channel and developed a probabilistic model under stochastic fog conditions. Furthermore, we studied the performance of the FSO system addressing various performance metrics, including signal-to-noise ratio (SNR), bit-error rate (BER), and channel capacity. Our results show that in communication environments with frequent fog, FSO is typically a short-range data transmission technology. Therefore, FSO will have its preferred market segment in future wireless fifth-generation/sixth-generation (5G/6G) networks having cell sizes that are lower than a 1-km diameter. Moreover, the results of our modeling and analysis can be applied in determining the switching/thresholding conditions in highly reliable hybrid FSO/radio-frequency (RF) networks.

  4. Variable optical attenuator fabricated by direct UV writing

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Færch, Kjartan Ullitz; Andersen, L.U.

    2003-01-01

    It is demonstrated that direct ultraviolet writing of waveguides is a method suitable for mass production of compact variable optical attenuators with low insertion loss, low polarization-dependent loss, and high dynamic range. The fabrication setup is shown to be robust, providing good device...

  5. Engineering attenuated virulence of a Theileria annulata-infected macrophage.

    Directory of Open Access Journals (Sweden)

    Nadia Echebli

    Full Text Available Live attenuated vaccines are used to combat tropical theileriosis in North Africa, the Middle East, India, and China. The attenuation process is empirical and occurs only after many months, sometimes years, of in vitro culture of virulent clinical isolates. During this extensive culturing, attenuated lines lose their vaccine potential. To circumvent this we engineered the rapid ablation of the host cell transcription factor c-Jun, and within only 3 weeks the line engineered for loss of c-Jun activation displayed in vitro correlates of attenuation such as loss of adhesion, reduced MMP9 gelatinase activity, and diminished capacity to traverse Matrigel. Specific ablation of a single infected host cell virulence trait (c-Jun induced a complete failure of Theileria annulata-transformed macrophages to disseminate, whereas virulent macrophages disseminated to the kidneys, spleen, and lungs of Rag2/γC mice. Thus, in this heterologous mouse model loss of c-Jun expression led to ablation of dissemination of T. annulata-infected and transformed macrophages. The generation of Theileria-infected macrophages genetically engineered for ablation of a specific host cell virulence trait now makes possible experimental vaccination of calves to address how loss of macrophage dissemination impacts the disease pathology of tropical theileriosis.

  6. PAUT inspection of copper canister: Structural attenuation and POD formulation

    Science.gov (United States)

    Gianneo, A.; Carboni, M.; Mueller, C.; Ronneteg, U.

    2016-02-01

    For inspection of thick-walled (50mm) copper canisters for final disposal of spent nuclear fuel in Sweden, ultrasonic inspection using phased array technique (PAUT) is applied. Because thick-walled copper is not commonly used as a structural material, previous experience on Phased Array Ultrasonic Testing for this type of application is limited. The paper presents the progress in understanding the amplitudes and attenuation changes acting on the Phased Array Ultrasonic Testing inspection of copper canisters. Previous studies showed the existence of a low pass filtering effect and a heterogeneous grain size distribution along the depth, thus affecting both the detectability of defects and their "Probability of Detection" determination. Consequently, the difference between the first and second back wall echoes were not sufficient to determine the local attenuation (within the inspection range), which affects the signal response for each individual defect. Experimental evaluation of structural attenuation was carried out onto step-wedge samples cut from full-size, extruded and pierced & drawn, copper canisters. Effective attenuation values has been implemented in numerical simulations to achieve a Multi Parameter Probability of Detection and to formulate a Model Assisted Probability of Detection through a Monte-Carlo extraction model.

  7. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  8. Adaptive disturbance attenuation via logic-based switching

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mari, Daniele; Selvi, Daniela; Tesi, Alberto; Tesi, Pietro

    2014-01-01

    The problem of attenuating unknown and possibly time-varying disturbances acting on a linear time-invariant dynamical system is addressed by means of an adaptive switching control approach. Given a family of pre-designed stabilizing controllers, a supervisory unit infers in real-time the potential b

  9. Simple red-beam attenuation meter for sea truth measurements

    Energy Technology Data Exchange (ETDEWEB)

    Haltrin, V.I.; Lee, M.E.; Martynov, O.V. [Naval Research Lab., Stennis Space Center, MS (United States)

    1996-11-01

    Red beam attenuation is useful in analyzing profiles of remotely sensed hydrooptical parameters and for accurate resolution of the vertical structure of chlorophyll and suspended particles. Hence, the development of a probing red beam attenuation meter has practical interest. Auto-collimating optical schematics with a cat`s eye have been used in the meter developed. The instrument is intended for application both as an independent device and as a module for oceanographic systems. High accuracy with minimal size and power consumption are realized by using electro-optical semiconductors. The dual beam principle of stabilization with negative optical feedback for the light emitting diode (LED) is applied. The exponential shape of LED modulated impulses causes the instrument output to be proportional to beam attenuation. By placing the optical attenuator into the reference beam one can compensate for pure water absorption and measure the volume scattering coefficient. The optical base of the cat`s eye can be varied from 50 cm on down. The device is not sensitive to ambient light. 12 refs., 2 figs., 1 tab.

  10. Timing attention : Cuing target onset interval attenuates the attentional blink

    NARCIS (Netherlands)

    Martens, S; Johnson, A

    2005-01-01

    Three experiments tested whether the attentional blink (AB; a deficit in reporting the second of two targets when it occurs 200-500 msec after the first) can be attenuated by providing information about the target onset asynchrony (TOA) of the second target relative to the first. Blocking the TOA di

  11. Saturated hydrogen saline attenuates endotoxin-induced lung dysfunction.

    Science.gov (United States)

    Zhang, Yan; Liu, Yiming; Zhang, Jin

    2015-09-01

    Acute lung injury induced by lipopolysaccharides (LPSs) is caused by pulmonary inflammation and pulmonary vascular permeability. Activation of p38 mitogen-activated protein kinase causes inflammation, and proinflammatory cytokines and oxidative stress induce autophagy, a catabolic mechanism responsible for protein degradation and recycling of damaged proteins and cytoplasmic organelles. If not controlled, excessive autophagy responses can result in cell death. In this study, we pretreated rats with saturated hydrogen saline, and examined the molecular mechanism by which saturated hydrogen saline attenuates LPS-induced acute lung dysfunction. Sixty-four male Sprague-Dawley rats were randomly assigned to one of three groups--a control group, an LPS group, or an LPS plus saturated hydrogen saline (LPS + H2) group. Treatment with saturated hydrogen saline prolonged the median survival time of rats and reduced lung dysfunction induced by LPS. Moreover, saturated hydrogen saline significantly attenuated LPS-mediated induction of serum tumor necrosis factor α, interleukin 6, myeloperoxidase, and malondialdehyde (P hydrogen saline decreased the number of autophagosomes and LC3I/II expression. Saturated hydrogen saline also attenuated the LPS-mediated increase in apoptosis and p38 expression. Taken together, saturated hydrogen saline may attenuate LPS-induced acute lung dysfunction in rats by reducing inflammation, autophagy, and apoptosis involving the p38 mitogen-activated protein kinase signaling pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Optical Attenuation in MoNA and LISA Detector Elements

    Science.gov (United States)

    Rice, Logan; Wong, Jonathan; MoNA Collaboration

    2011-10-01

    The MoNA collaboration is a research group of students and faculty from 13 primarily undergraduate institutions, with detectors at the NSCL: MoNA (Modular Neutron Array) and the newly-built LISA (Large multi-Institutional Scintillating Array). These arrays each have 144 plastic scintillating bars. When a neutron collides with a hydrogen nucleus within the plastic, photomultiplier tubes at either end of the bar detect the scintillation photons. Their arrival times are used to determine the position of the event, but as the light travels through the detector it loses intensity exponentially. How dramatic this loss is can be described by a parameter called the attenuation length, with larger attenuation lengths corresponding to lower loss. Recently the MoNA collaboration conducted its LISA commissioning experiment investigating two-neutron decay states of 25O. As a part of LISA's commissioning, we measured the attenuation lengths of the individual detector bars that make up the LISA array and compared these lengths with those of the older MoNA array. We found that the LISA bars had a larger attenuation length on average with impacts on detector efficiency and effective threshold. The authors wish to acknowledge the contributions of the members of the MoNA Collaboration.

  13. Pyrrolidine Dithiocarbamate Attenuates Paraquat-Induced Lung Injury in Rats

    Directory of Open Access Journals (Sweden)

    Xiuli Chang

    2009-01-01

    PQ+PDTC-treated groups than that of PQ-treated groups (P<.05. The histopathological changes in the PQ+PDTC-treated groups were milder than those of PQ groups. Our results suggested that PDTC treatment significantly attenuated paraquat-induced pulmonary damage.

  14. Measurement of acoustic attenuation in South Pole ice

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bissok, M.; Blaufuss, E.; Boersma, D.J.; Bohm, C.; Boser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dreyer, J.; Dumm, J.P.; Duvoort, M.R.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gunasingha, R.M.; Gurtner, M.; Gustafsson, L.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G.C.; Hoffman, K.D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Lafebre, S.J.

    2011-01-01

    Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been

  15. On the effectiveness of mangroves in attenuating cyclone induced waves

    NARCIS (Netherlands)

    Narayan, S.; Suzuki, T.; Stive, M.J.F.; Verhagen, H.J.; Ursem, W.N.J.; Ranasinghe, R.

    2010-01-01

    A study of the effectiveness of mangroves in attenuating cyclone- induced waves was done using the SWAN 40.81 numerical model. Hydraulic parameters during extreme events and local mangrove vegetation parameters were estimated for the Kanika Sands mangrove island near the upcoming Dhamra Port in Oris

  16. Lg Attenuation Characteristic of Gujarat Region (Western India)

    Science.gov (United States)

    Jaiswal, Namrata; Singh, Chandrani

    2016-04-01

    We estimate the Lg attenuation characteristics of the Gujarat Region in Western India by using a reliable two-station method. This region comes under the V, IV and III seismicity zone. So, in India this is the seismic active region other than Himalayas, which shows high seismicity. Lg is typically the most prominent short-period seismic phase on high frequency seismogram observed over the continental paths from regional to teleseimic distance. We use data from 15 earthquakes with magnitude > 5 mb and focal depth Lg Q (Q0) values between many pairs of stations. Finally, 5 events with 70 high-quality inter-station paths were selected from 117 possible pairs of stations that are (1) aligned approximately with the source and (2) separated enough to permit the use of the standard two-station method for Lg Q measurement. Spatial variations in Q0 have been noticed across the Gujarat region. Low Q0 ( 300) value. These observations are consistent with the results of the body wave attenuation structure reported for the region. The variations in the attenuation characteristics may be caused due to both the intrinsic and scattering contributions caused by thermal effects, sedimentary layer thickness as well as heterogeneities present below the study region. Our results are found to be comparable with the previous studies of the attenuation characteristics of the Gujarat region.

  17. A CMOS Wideband Linear Current Attenuator with Electronically Variable Gain

    NARCIS (Netherlands)

    Wiegerink, Remco J.

    1993-01-01

    A CMOS highly linear current attenuator is described. The circuit is suited for both differential and single input currents. The current gain is electronically variable between -1 and +1 by means of two controlling currents. A simple additional circuit is described to obtain a gain that is linearly

  18. Low-energy gamma ray attenuation characteristics of aviation fuels

    Science.gov (United States)

    Singh, Jag J.; Shen, Chih-Ping; Sprinkle, Danny R.

    1990-01-01

    Am241 (59.5 keV) gamma ray attenuation characteristics were investigated in 270 aviation fuel (Jet A and Jet A-1) samples from 76 airports around the world as a part of world wide study to measure the variability of aviation fuel properties as a function of season and geographical origin. All measurements were made at room temperature which varied from 20 to 27 C. Fuel densities (rho) were measured concurrently with their linear attenuation coefficients (mu), thus providing a measure of mass attenuation coefficient (mu/rho) for the test samples. In 43 fuel samples, rho and mu values were measured at more than one room temperature, thus providing mu/rho values for them at several temperatures. The results were found to be independent of the temperature at which mu and rho values were measured. It is noted that whereas the individual mu and rho values vary considerably from airport to airport as well as season to season, the mu/rho values for all samples are constant at 0.1843 + or - 0.0013 cu cm/gm. This constancy of mu/rho value for aviation fuels is significant since a nuclear fuel quantity gauging system based on low energy gamma ray attenuation will be viable throughout the world.

  19. Simultaneous amplification and attenuation in isotropic chiral materials

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    The electromagnetic field phasors in an isotropic chiral material (ICM) are superpositions of two Beltrami fields of different handedness. Application of the Bruggeman homogenization formalism to two-component composite materials delivers ICMs wherein Beltrami fields of one handedness attenuate whereas Beltrami waves of the other handedness amplify. One component material is a dissipative ICM, the other an active dielectric material.

  20. Wogonin Induces Eosinophil Apoptosis and Attenuates Allergic Airway Inflammation

    Science.gov (United States)

    Dorward, David A.; Sharma, Sidharth; Rennie, Jillian; Felton, Jennifer M.; Alessandri, Ana L.; Duffin, Rodger; Schwarze, Jurgen; Haslett, Christopher; Rossi, Adriano G.

    2015-01-01

    Rationale: Eosinophils are key effector cells in allergic diseases, including allergic rhinitis, eczema, and asthma. Their tissue presence is regulated by both recruitment and increased longevity at inflamed sites. Objectives: To investigate the ability of the flavone wogonin to induce eosinophil apoptosis in vitro and attenuate eosinophil-dominant allergic inflammation in vivo in mice. Methods: Human and mouse eosinophil apoptosis in response to wogonin was investigated by cellular morphology, flow cytometry, mitochondrial membrane permeability, and pharmacological caspase inhibition. Allergic lung inflammation was modeled in mice sensitized and challenged with ovalbumin. Bronchoalveolar lavage (BAL) and lung tissue were examined for inflammation, mucus production, and inflammatory mediator production. Airway hyperresponsiveness to aerosolized methacholine was measured. Measurements and Main Results: Wogonin induced time- and concentration-dependent human and mouse eosinophil apoptosis in vitro. Wogonin-induced eosinophil apoptosis occurred with activation of caspase-3 and was inhibited by pharmacological caspase inhibition. Wogonin administration attenuated allergic airway inflammation in vivo with reductions in BAL and interstitial eosinophil numbers, increased eosinophil apoptosis, reduced airway mucus production, and attenuated airway hyperresponsiveness. This wogonin-induced reduction in allergic airway inflammation was prevented by concurrent caspase inhibition in vivo. Conclusions: Wogonin induces eosinophil apoptosis and attenuates allergic airway inflammation, suggesting that it has therapeutic potential for the treatment of allergic inflammation in humans. PMID:25629436

  1. Wave attenuation in thick graphite/epoxy composites

    Science.gov (United States)

    Mal, A. K.; Bar-Cohen, Y.

    1992-01-01

    The mechanics of wave attenuation in thick graphite/epoxy composites is examined in order to facilitate interpretation of the wave amplitudes recorded in ultrasonic experiments. The values of a small number of parameters are determined through comparison between calculated and measured waveforms for four specimens. The agreement between the measured and calculated waveforms are shown to be excellent in all four cases.

  2. Attenuation of ground vibrations due to different technical sources

    Institute of Scientific and Technical Information of China (English)

    L. Auersch; S. Said

    2010-01-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ~ r where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  3. On the effectiveness of mangroves in attenuating cyclone induced waves

    NARCIS (Netherlands)

    Narayan, S.; Suzuki, T.; Stive, M.J.F.; Verhagen, H.J.; Ursem, W.N.J.; Ranasinghe, R.

    2010-01-01

    A study of the effectiveness of mangroves in attenuating cyclone- induced waves was done using the SWAN 40.81 numerical model. Hydraulic parameters during extreme events and local mangrove vegetation parameters were estimated for the Kanika Sands mangrove island near the upcoming Dhamra Port in

  4. Attenuation of Rayleigh Surface Waves in a Porous Material

    Institute of Scientific and Technical Information of China (English)

    DEBBOUB Salima; BOUMA(I)ZA Youcef; BOUDOUR Amar; TAHRAOUI Tarek

    2012-01-01

    Using acoustic microscopy at higher frequency,we show the velocity evolutions of surface acoustic waves,in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer.The velocities are obtained from different V(z) curves,which are determined experimentally at a frequency of 600MHz.The analysis of V(z) data yields attenuation that is directly dependent on porosity.On the other hand,αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.%Using acoustic microscopy at higher frequency, we show the velocity evolutions of surface acoustic waves, in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer. The velocities are obtained from different V(z) curves, which are determined experimentally at a frequency of 600 MHz. The analysis of V(z) data yields attenuation that is directly dependent on porosity. On the other hand, αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.

  5. Closed-Loop Control of MEMS Variable Optical Attenuator (VOA)

    Institute of Scientific and Technical Information of China (English)

    H.Cai; X.; M.; Zhang; A.; Q.; Liu; Y.; X.; Wang; C.; Lu

    2003-01-01

    This paper reports the development of an optical power regulator based on surface-micromachined variable optical attenuators (VOAs). By use of closed-loop control circuits, each VOA module implements the functions of power setpoint tracking, disturbance rejection and ripple suppression.

  6. A CMOS Wideband Linear Current Attenuator with Electronically Variable Gain

    NARCIS (Netherlands)

    Wiegerink, Remco J.

    1993-01-01

    A CMOS highly linear current attenuator is described. The circuit is suited for both differential and single input currents. The current gain is electronically variable between -1 and +1 by means of two controlling currents. A simple additional circuit is described to obtain a gain that is linearly

  7. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær

    2012-01-01

    was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...... concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%), for kidneys 20 ± 1% (19......–21%), and for bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude...

  8. Attenuation studies of booster-rocket propellants and their simulants

    Energy Technology Data Exchange (ETDEWEB)

    Weirick, L.J.

    1990-08-01

    A series of impact experiments on a composite propellant, an energetic propellant, and their simulants was recently completed using a light-gas gun. Previous experiments were done to obtain Hugoniot data, to investigate the pressure threshold at which a reaction occurs, and to measure spall damage at various impact velocities. The present studies measured the attenuation of shock waves in these materials, completing the shock characterization needed for material modeling. An initial impulse of 2.0 GPa magnitude and {approximately}0.6 {mu}s duration was imposed upon samples of various thicknesses. VISAR was used to measure the free-surface velocity at the back of the samples; these data were used to generate a curve of shock-wave attenuation versus sample thickness for each material. Results showed that all four materials attenuated the shock wave very similarly. Material thicknesses of 3.0, 7.62, 12.7, and 19.0 mm attenuated the shock wave {approximately}16%, 33%, 50%, and 66% respectively. 14 refs., 12 figs., 4 tabs.

  9. Attenuated familial adenomatous polyposis (AFAP). A review of the literature

    DEFF Research Database (Denmark)

    Knudsen, Anne Lyster; Bisgaard, Marie Luise; Bülow, Steffen

    2003-01-01

    Over the last decade, a subset of familial adenomatous polyposis (FAP) patients with a milder course of disease termed attenuated familial adenomatous polyposis (AFAP) has been described. AFAP is not well-defined as a disease entity - the reports on AFAP are largely casuistic or only deal...

  10. Attenuated familial adenomatous polyposis (AFAP). A review of the literature

    DEFF Research Database (Denmark)

    Knudsen, Anne Lyster; Bisgaard, Marie Luise; Bülow, Steffen

    2003-01-01

    Over the last decade, a subset of familial adenomatous polyposis (FAP) patients with a milder course of disease termed attenuated familial adenomatous polyposis (AFAP) has been described. AFAP is not well-defined as a disease entity - the reports on AFAP are largely casuistic or only deal with a ...

  11. Laboratory measurements of seismic attenuation in partially saturated rocks

    Science.gov (United States)

    Chapman, Samuel; Tisato, Nicola; Quintal, Beatriz; Holliger, Klaus

    2014-05-01

    Laboratory measurements of seismic attenuation and transient pore fluid pressure are performed on partially saturated Berea sandstone and synthetic borosilicate samples. Various degrees of water (liquid) and nitrogen (gas) saturation are considered. These measurements are carried out at room temperature and under confining pressures varying from ambient conditions up to 25 MPa. The cylindrical samples are 25 cm long and have a diameter of 7.6 cm. In the context of the experimental setup, the solid frames of both the Berea sandstone and the borosilicate samples can be considered homogenous, which in turn allows for isolating and exploring the effects of partial saturation on seismic attenuation. We employ the sub-resonance method, which is based on the application of a time-harmonic vertical stress to the top of the sample and the measurement of the thus resulting strain. For any given frequency, the attenuation is then inferred as the tangent of the phase shift between the applied stress and the observed strain. Using five equally spaced sensors along the central axis of the cylindrical sample, we measure the transient fluid pressure induced by the application of a step-function-type vertical stress to the top of the sample. Both the sensors and the sample are sealed off with the regard to the confining environment. Together with the numerical results from corresponding compressibility tests based on the quasi-static poroelastic equations, these transient fluid pressure measurements are then used to assist the interpretation of the seismic attenuation measurements.

  12. Enzyme-treated Asparagus officinalis extract shows neuroprotective effects and attenuates cognitive impairment in senescence-accelerated mice.

    Science.gov (United States)

    Sakurai, Takuya; Ito, Tomohiro; Wakame, Koji; Kitadate, Kentaro; Arai, Takashi; Ogasawara, Junetsu; Kizaki, Takako; Sato, Shogo; Ishibashi, Yoshinaga; Fujiwara, Tomonori; Akagawa, Kimio; Ishida, Hitoshi; Ohno, Hideki

    2014-01-01

    Increases in the number of patients with dementia involving Alzheimer's disease (AD) are seen as a grave public health problem. In neurodegenerative disorders involving AD, biological stresses, such as oxidative and inflammatory stress, induce neural cell damage. Asparagus (Asparagus officinalis) is a popular vegetable, and an extract prepared from this reportedly possesses various beneficial biological activities. In the present study, we investigated the effects of enzyme-treated asparagus extract (ETAS) on neuronal cells and early cognitive impairment of senescence-accelerated mouse prone 8 (SAMP8) mice. The expression of mRNAs for factors that exert cytoprotective and anti-apoptotic functions, such as heat-shock protein 70 and heme oxygenase-1, was upregulated in NG108-15 neuronal cells by treatment with ETAS. Moreover, when release of lactate dehydrogenase from damaged NG108-15 cells was increased for cells cultured in medium containing either the nitric oxide donor sodium nitroprusside or the hypoxia mimic reagent cobalt chloride, ETAS significantly attenuated this cell damage. Also, when contextual fear memory, which is considered to be a hippocampus-dependent memory, was significantly impaired in SAMP8 mice, ETAS attenuated the cognitive impairment. These results suggest that ETAS produces cytoprotective effects in neuronal cells and attenuates the effects on the cognitive impairment of SAMP8 mice.

  13. Treatment of mice with fenbendazole attenuates allergic airways inflammation and Th2 cytokine production in a model of asthma.

    Science.gov (United States)

    Cai, Yeping; Zhou, Jiansheng; Webb, Dianne C

    2009-01-01

    Mouse models have provided a significant insight into the role of T-helper (Th) 2 cytokines such as IL-5 and IL-13 in regulating eosinophilia and other key features of asthma. However, the validity of these models can be compromised by inadvertent infection of experimental mouse colonies with pathogens such as oxyurid parasites (pinworms). While the benzimidazole derivative, fenbendazole (FBZ), is commonly used to treat such outbreaks, the effects of FBZ on mouse models of Th2 disease are largely unknown. In this investigation, we show that mice fed FBZ-supplemented food during the in utero and post-weaning period developed attenuated lung eosinophilia, antigen-specific IgG1 and Th2 cytokine responses in a model of asthma. Treatment of the mediastinal lymph node cells from allergic mice with FBZ in vitro attenuated cell proliferation, IL-5 and IL-13 production and expression of the early lymphocyte activation marker, CD69 on CD4(+) T cells and CD19(+) B cells. In addition, eosinophilia and Th2 responses remained attenuated after a 4-week withholding period in allergic mice treated preweaning with FBZ. Thus, FBZ modulates the amplitude of Th2 responses both in vivo and in vitro.

  14. Evaluation of live attenuated S79 mumps vaccine effectiveness in mumps outbreaks: a matched case-control study

    Institute of Scientific and Technical Information of China (English)

    FU Chuan-xi; NIE Jun; LIANG Jian-hua; WANG Ming

    2009-01-01

    Background Mumps virus infection is a potentially serious viral infection of childhood and early adulthood. In China, live attenuated S79 mumps vaccine has been licensed for pediatric use since 1990. The objective of this study was to determine the effectiveness of live attenuated S79 mumps vaccine against clinical mumps in outbreaks.Methods Cases were selected from mumps outbreaks in schools in Guangzhou between 2004 and 2005. Each case was matched by gender, age and classroom. Vaccination information was obtained from Children's EPI Administrative Computerized System. Vaccine effectiveness (VE) was calculated for 1 or 2 doses of S79 vaccine with 95% confidence intervals (CI).Results One hundred and ninety-four cases and 194 controls were enrolled into the study. VE of the S79 mumps vaccine for 1 dose versus 0 confer protection 80.4% (95% CI, 60.0%-90.4%) and Ves against mumps in outbreaks for 1 dose of mumps vaccine are similar among those children aged 4-9 years and aged over 10 years old.Conclusion The live attenuated S79 mumps vaccine can be effective in preventing clinical mumps outbreaks.

  15. Apigenin Attenuates Atherogenesis through Inducing Macrophage Apoptosis via Inhibition of AKT Ser473 Phosphorylation and Downregulation of Plasminogen Activator Inhibitor-2

    OpenAIRE

    Ping Zeng; Bin Liu; Qun Wang; Qin Fan; Jian-Xin Diao; Jing Tang; Xiu-Qiong Fu; Xue-Gang Sun

    2015-01-01

    Macrophage survival is believed to be a contributing factor in the development of early atherosclerotic lesions. Dysregulated apoptosis of macrophages is involved in the inflammatory process of atherogenesis. Apigenin is a flavonoid that possesses various clinically relevant properties such as anti-inflammatory, antiplatelet, and antitumor activities. Here we showed that apigenin attenuated atherogenesis in apoE-/- mice in an in vivo test. In vitro experiments suggested that apigenin induced ...

  16. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  17. Seismic wave attenuation and velocity dispersion in UAE carbonates

    Science.gov (United States)

    Ogunsami, Abdulwaheed Remi

    Interpreting the seismic property of fluids in hydrocarbon reservoirs at low frequency scale has been a cherished goal of petroleum geophysics research for decades. Lately, there has been tremendous interest in understanding attenuation as a result of fluid flow in porous media. Although interesting, the emerging experimental and theoretical information still remain ambiguous and are practically not utilized for reasons not too obscure. Attenuation is frequency dependent and hard to measure in the laboratory at low frequency. This thesis describes and reports the results of an experimental study of low frequency attenuation and velocity dispersion on a selected carbonate reservoir samples in the United Arab Emirates (UAE). For the low frequency measurements, stress-strain method was used to measure the moduli from which the velocity is derived. Attenuation was measured as the phase difference between the applied stress and the strain. For the ultrasonic component, the pulse propagation method was employed. To study the fluid effect especially at reservoir in situ conditions, the measurements were made dry and saturated with liquid butane and brine at differential pressures of up to 5000 psi with pore pressure held constant at 500 psi. Similarly to what has been documented in the literatures for sandstone, attenuation of the bulk compressibility mode dominates the losses in these dry and somewhat partially saturated carbonate samples with butane and brine. Overall, the observed attenuation cannot be simply said to be frequency dependent within this low seismic band. While attenuation seems to be practically constant in the low frequency band for sample 3H, such conclusion cannot be made for sample 7H. For the velocities, significant dispersion is observed and Gassmann generally fails to match the measured velocities. Only the squirt model fairly fits the velocities, but not at all pressures. Although the observed dispersion is larger than Biot's prediction, the fact

  18. Cement-based materials' characterization using ultrasonic attenuation

    Science.gov (United States)

    Punurai, Wonsiri

    The quantitative nondestructive evaluation (NDE) of cement-based materials is a critical area of research that is leading to advances in the health monitoring and condition assessment of the civil infrastructure. Ultrasonic NDE has been implemented with varying levels of success to characterize cement-based materials with complex microstructure and damage. A major issue with the application of ultrasonic techniques to characterize cement-based materials is their inherent inhomogeneity at multiple length scales. Ultrasonic waves propagating in these materials exhibit a high degree of attenuation losses, making quantitative interpretations difficult. Physically, these attenuation losses are a combination of internal friction in a viscoelastic material (ultrasonic absorption), and the scattering losses due to the material heterogeneity. The objective of this research is to use ultrasonic attenuation to characterize the microstructure of heterogeneous cement-based materials. The study considers a real, but simplified cement-based material, cement paste---a common bonding matrix of all cement-based composites. Cement paste consists of Portland cement and water but does not include aggregates. First, this research presents the findings of a theoretical study that uses a set of existing acoustics models to quantify the scattered ultrasonic wavefield from a known distribution of entrained air voids. These attenuation results are then coupled with experimental measurements to develop an inversion procedure that directly predicts the size and volume fraction of entrained air voids in a cement paste specimen. Optical studies verify the accuracy of the proposed inversion scheme. These results demonstrate the effectiveness of using attenuation to measure the average size, volume fraction of entrained air voids and the existence of additional larger entrapped air voids in hardened cement paste. Finally, coherent and diffuse ultrasonic waves are used to develop a direct

  19. Signal attenuation as a rat model of obsessive compulsive disorder.

    Science.gov (United States)

    Goltseker, Koral; Yankelevitch-Yahav, Roni; Albelda, Noa S; Joel, Daphna

    2015-01-09

    In the signal attenuation rat model of obsessive-compulsive disorder (OCD), lever-pressing for food is followed by the presentation of a compound stimulus which serves as a feedback cue. This feedback is later attenuated by repeated presentations of the stimulus without food (without the rat emitting the lever-press response). In the next stage, lever-pressing is assessed under extinction conditions (i.e., no food is delivered). At this stage rats display two types of lever-presses, those that are followed by an attempt to collect a reward, and those that are not. The latter are the measure of compulsive-like behavior in the model. A control procedure in which rats do not experience the attenuation of the feedback cue serves to distinguish between the effects of signal attenuation and of extinction. The signal attenuation model is a highly validated model of OCD and differentiates between compulsive-like behaviors and behaviors that are repetitive but not compulsive. In addition the measures collected during the procedure eliminate alternative explanations for differences between the groups being tested, and are quantitative, unbiased and unaffected by inter-experimenter variability. The major disadvantages of this model are the costly equipment, the fact that it requires some technical know-how and the fact that it is time-consuming compared to other models of OCD (11 days). The model may be used for detecting the anti- or pro-compulsive effects of pharmacological and non-pharmacological manipulations and for studying the neural substrate of compulsive behavior.

  20. A galU mutant of francisella tularensis is attenuated for virulence in a murine pulmonary model of tularemia

    Directory of Open Access Journals (Sweden)

    Re Fabio

    2011-08-01

    Full Text Available Abstract Background A number of studies have revealed that Francisella tularensis (FT suppresses innate immune responses such as chemokine/cytokine production and neutrophil recruitment in the lungs following pulmonary infection via an unidentified mechanism. The ability of FT to evade early innate immune responses could be a very important virulence mechanism for this highly infectious bacterial pathogen. Results Here we describe the characterization of a galU mutant strain of FT live vaccine strain (LVS. We show that the galU mutant was highly attenuated in a murine model of tularemia and elicited more robust innate immune responses than the wild-type (WT strain. These studies document that the kinetics of chemokine expression and neutrophil recruitment into the lungs of mice challenged with the galU mutant strain are significantly more rapid than observed with WT FT, despite the fact that there were no observed differences in TLR2 or TLR4 signaling or replication/dissemination kinetics during the early stages of infection. We also show that the galU mutant had a hypercytotoxic phenotype and more rapidly induced the production of IL-1β following infection either in vitro or in vivo, indicating that attenuation of the galU mutant strain may be due (in part to more rapid activation of the inflammasome and/or earlier death of FT infected cells. Furthermore, we show that infection of mice with the galU mutant strain elicits protective immunity to subsequent challenge with WT FT. Conclusions Disruption of the galU gene of FTLVS has little (if any effect on in vivo infectivity, replication, or dissemination characteristics, but is highly attenuating for virulence. The attenuated phenotype of this mutant strain of FT appears to be related to its increased ability to induce innate inflammatory responsiveness, resulting in more rapid recruitment of neutrophils to the lungs following pneumonic infection, and/or to its ability to kill infected cells in

  1. Exercise attenuates inflammation and limits scar thinning after myocardial infarction in mice.

    Science.gov (United States)

    Puhl, Sarah-Lena; Müller, Andreas; Wagner, Michael; Devaux, Yvan; Böhm, Michael; Wagner, Daniel R; Maack, Christoph

    2015-07-15

    Although exercise mediates beneficial effects in patients after myocardial infarction (MI), the underlying mechanisms as well as the question of whether an early start of exercise after MI is safe or even beneficial are incompletely resolved. The present study analyzed the effects of exercise before and reinitiated early after MI on cardiac remodeling and function. Male C57BL/6N mice were housed sedentary or with the opportunity to voluntarily exercise for 6 wk before MI induction (ligation of the left anterior descending coronary artery) or sham operation. After a 5-day exercise-free phase after MI, mice were allowed to reexercise for another 4 wk. Exercise before MI induced adaptive hypertrophy with moderate increases in heart weight, cardiomyocyte diameter, and left ventricular (LV) end-diastolic volume, but without fibrosis. In sedentary mice, MI induced eccentric LV hypertrophy with massive fibrosis but maintained systolic LV function. While in exercised mice gross LV end-diastolic volumes and systolic function did not differ from sedentary mice after MI, LV collagen content and thinning of the infarcted area were reduced. This was associated with ameliorated activation of inflammation, mediated by TNF-α, IL-1β, and IL-6, as well as reduced activation of matrix metalloproteinase 9. In contrast, no differences in the activation patterns of various MAPKs or adenosine receptor expressions were observed 5 wk after MI in sedentary or exercised mice. In conclusion, continuous exercise training before and with an early reonset after MI ameliorates adverse LV remodeling by attenuating inflammation, fibrosis, and scar thinning. Therefore, an early reonset of exercise after MI can be encouraged.

  2. IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

    Science.gov (United States)

    Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

  3. CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

    Science.gov (United States)

    Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

    2015-09-01

    This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

  4. Vaccination with live attenuated simian immunodeficiency virus causes dynamic changes in intestinal CD4+CCR5+ T cells

    Directory of Open Access Journals (Sweden)

    Elsley William

    2011-02-01

    Full Text Available Abstract Background Vaccination with live attenuated SIV can protect against detectable infection with wild-type virus. We have investigated whether target cell depletion contributes to the protection observed. Following vaccination with live attenuated SIV the frequency of intestinal CD4+CCR5+ T cells, an early target of wild-type SIV infection and destruction, was determined at days 3, 7, 10, 21 and 125 post inoculation. Results In naive controls, modest frequencies of intestinal CD4+CCR5+ T cells were predominantly found within the LPL TTrM-1 and IEL TTrM-2 subsets. At day 3, LPL and IEL CD4+CCR5+ TEM cells were dramatically increased whilst less differentiated subsets were greatly reduced, consistent with activation-induced maturation. CCR5 expression remained high at day 7, although there was a shift in subset balance from CD4+CCR5+ TEM to less differentiated TTrM-2 cells. This increase in intestinal CD4+CCR5+ T cells preceded the peak of SIV RNA plasma loads measured at day 10. Greater than 65.9% depletion of intestinal CD4+CCR5+ T cells followed at day 10, but overall CD4+ T cell homeostasis was maintained by increased CD4+CCR5- T cells. At days 21 and 125, high numbers of intestinal CD4+CCR5- naive TN cells were detected concurrent with greatly increased CD4+CCR5+ LPL TTrM-2 and IEL TEM cells at day 125, yet SIV RNA plasma loads remained low. Conclusions This increase in intestinal CD4+CCR5+ T cells, following vaccination with live attenuated SIV, does not correlate with target cell depletion as a mechanism of protection. Instead, increased intestinal CD4+CCR5+ T cells may correlate with or contribute to the protection conferred by vaccination with live attenuated SIV.

  5. Frontal lobe changes occur early in the course of affective disorders in young people

    Directory of Open Access Journals (Sweden)

    Lagopoulos Jim

    2012-01-01

    Full Text Available Abstract Background More severe and persistent forms of affective disorders are accompanied by grey matter loss in key frontal and temporal structures. It is unclear whether such changes precede the onset of illness, occur early in the course or develop gradually with persistence or recurrence of illness. A total of 47 young people presenting with admixtures of depressive and psychotic symptoms were recruited from specialist early intervention services along with 33 age matched healthy control subjects. All participants underwent magnetic resonance imaging and patients were rated clinically as to current stage of illness. Twenty-three patients were identified as being at an early 'attenuated syndrome' stage, while the remaining were rated as having already reached the 'discrete disorder' or 'persistent or recurrent illness' stage. Contrasts were carried out between controls subjects and patients cohorts with attenuated syndromes and discrete disorders, separately. Results The patients that were identified as having a discrete or persisting disorder demonstrated decreased grey matter volumes within distributed frontal brain regions when contrasted to both the control subjects as well as those patients in the attenuated syndrome stage. Overall, patients who were diagnosed as more advanced in terms of the clinical stage of their illness, exhibited the greatest grey matter volume loss of all groups. Conclusions This study suggests that, in terms of frontal grey matter changes, a major transition point may occur in the course of affective illness between early attenuated syndromes and later discrete illness stages.

  6. Evasion of early innate immune response by 2'-O-methylation of dengue genomic RNA.

    Science.gov (United States)

    Chang, David C; Hoang, Long T; Mohamed Naim, Ahmad Nazri; Dong, Hongping; Schreiber, Mark J; Hibberd, Martin L; Tan, Min Jie Alvin; Shi, Pei-Yong

    2016-12-01

    Dengue virus (DENV) is the most prevalent mosquito-borne virus pathogen in humans. There is currently no antiviral therapeutic or widely available vaccine against dengue infection. The DENV RNA genome is methylated on its 5' cap by its NS5 protein. DENV bearing a single E216A point mutation in NS5 loses 2'-O-methylation of its genome. While this mutant DENV is highly attenuated and immunogenic, the mechanism of this attenuation has not been elucidated. In this study, we find that replication of this mutant DENV is attenuated very early during infection. This early attenuation is not dependent on a functional type I interferon response and coincides with early activation of the innate immune response. Taken together, our data suggest that 2'-O-methylation of DENV genomic RNA is important for evasion of the host immune response during the very early stages of infection as the virus seeks to establish infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Computed tomography in the early detection of congenital lipoid adrenal hyperplasia

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, T.; Ishikawa, K.; Matsuo, N.; Kohda, E.

    1988-05-01

    This paper describes the successful use of abdominal computed tomography (CT) scan in diagnosing congenital lipoid adrenal hyperplasia in a Japanese male with no virilization at 9 days of age. The CT unequivocally delineated massively enlarged adrenal glands of fat-tissue attenuation, enabling early replacement therapy.

  8. Physical modeling and analysis of P-wave attenuation anisotropy in transversely isotropic media

    Digital Repository Service at National Institute of Oceanography (India)

    Zhu, Y.; Tsvankin, I.; Dewangan, P.; Van Wijk, K.

    Anisotropic attenuation can provide sensitive attributes for fracture detection and lithology discrimination. This paper analyzes measurements of the P-wave attenuation coefficient in a transversely isotropic sample made of phenolic material. Using...

  9. Sensitivity of benzene natural attenuation to variations in kinetic and transport parameters in Liwa Aquifer, UAE.

    Science.gov (United States)

    Mohamed, Mohamed M; Saleh, Nawal E; Sherif, Mohsen M

    2010-04-01

    Dissolved benzene was detected in the shallow unconfined Liwa aquifer (UAE). This aquifer represents the main freshwater source for a nearby residence camp area. A finite element model is used to simulate the fate, transport, and attenuation of the dissolved benzene plume to help decision makers assess natural attenuation as a viable remediation option. Sensitivity of benzene attenuation to uncertainties in the estimation of some of the kinetic and transport parameters is studied. It was found that natural attenuation is more sensitive to microbial growth rate and half saturation coefficients of both benzene and oxygen than initial biomass concentration and dispersivity coefficients. Increasing microbial growth rate by fourfold increased natural attenuation effectiveness after 40 years by 10%; while decreasing it by fourfold decreased natural attenuation effectiveness by 77%. On the other hand, increasing half saturation coefficient by fourfold decreased natural attenuation effectiveness by 46% in 40 years. Decreasing the same parameter fourfold caused natural attenuation effectiveness to increase by 9%.

  10. Monitored Natural Attenuation For Inorganic Contaminants In Ground Water - Technical Issues

    Science.gov (United States)

    Remediation of ground water contaminated with radionuclides may be achieved using attenuation-based technologies. These technologies may rely on engineered processes (e.g., bioremediation) or natural processes (e.g., monitored natural attenuation) within the subsurface. In gene...

  11. ICP4-induced miR-101 attenuates HSV-1 replication.

    Science.gov (United States)

    Wang, Xiangling; Diao, Caifeng; Yang, Xi; Yang, Zhen; Liu, Min; Li, Xin; Tang, Hua

    2016-03-17

    Hepes simplex Virus type 1 (HSV-1) is an enveloped DNA virus that can cause lytic and latent infection. miRNAs post-transcriptionally regulate gene expression, and our previous work has indicated that HSV-1 infection induces miR-101 expression in HeLa cells. The present study demonstrates that HSV-1-induced miR-101 is mainly derived from its precursor hsa-mir-101-2, and the HSV-1 immediate early gene ICP4 (infected-cell polypeptide 4) directly binds to the hsa-mir-101-2 promoter to activate its expression. RNA-binding protein G-rich sequence factor 1 (GRSF1) was identified as a new target of miR-101; GRSF1 binds to HSV-1 p40 mRNA and enhances its expression, facilitating viral proliferation. Together, ICP4 induces miR-101 expression, which downregulates GRSF1 expression and attenuates the replication of HSV-1. This allows host cells to maintain a permissive environment for viral replication by preventing lytic cell death. These findings indicate that HSV-1 early gene expression modulates host miRNAs to regulate molecular defense mechanisms. This study provides novel insight into host-virus interactions in HSV-1 infection and may contribute to the development of antiviral therapeutics.

  12. Intercellular adhesion molecule-1 blockade attenuates inflammatory response and improves microvascular perfusion in rat pancreas grafts.

    Science.gov (United States)

    Preissler, Gerhard; Eichhorn, Martin; Waldner, Helmut; Winter, Hauke; Kleespies, Axel; Massberg, Steffen

    2012-10-01

    After pancreas transplantation (PTx), early capillary malperfusion and leukocyte recruitment indicate the manifestation of severe ischemia/reperfusion injury (IRI). Oscillatory blood-flow redistribution (intermittent capillary perfusion, IP), leading to an overall decrease in erythrocyte flux, precedes complete microvascular perfusion failure with persistent blood flow cessation. We addressed the role of intercellular adhesion molecule-1 (ICAM-1) for leukocyte-endothelial interactions (LEIs) after PTx and evaluated the contribution of IP and malperfusion. Pancreas transplantation was performed in rats after 18-hour preservation, receiving either isotype-matched IgG or monoclonal anti-ICAM-1 antibodies (10 mg/kg intravenously) once before reperfusion. Leukocyte-endothelial interaction, IP, erythrocyte flux, and functional capillary density, respectively, were examined in vivo during 2-hour reperfusion. Nontransplanted animals served as controls. Tissue samples were analyzed by histomorphometry. In grafts of IgG-treated animals, IP was encountered already at an early stage after reperfusion and steadily increased over 2 hours, whereas erythrocyte flux declined continuously. In contrast, inhibition of ICAM-1 significantly improved erythrocyte flux and delayed IP appearance by 2 hours. Further, anti-ICAM-1 significantly reduced LEI and leukocyte tissue infiltration when compared to IgG; edema development was less pronounced in response to anti-ICAM-1 monoclonal antibody. Intercellular adhesion molecule-1 blockade significantly attenuates IRI via immediate reduction of LEI and concomitant improvement of capillary perfusion patterns, emphasizing its central role during IRI in PTx.

  13. Inhibition of adenosine deaminase attenuates endotoxin-induced release of cytokines in vivo in rats.

    Science.gov (United States)

    Tofovic, S P; Zacharia, L; Carcillo, J A; Jackson, E K

    2001-09-01

    The purpose of this study was to investigate in vivo the effects of modulating the adenosine system on endotoxin-induced release of cytokines and changes in heart performance and neurohumoral status in early, profound endotoxemia in rats. Time/pressure variables of heart performance and blood pressure were recorded continuously, and plasma levels of tumor necrosis factor alpha (TNFalpha), interleukin 1-beta (IL-1beta), plasma renin activity (PRA), and catecholamines were determined before and 90 min after administration of endotoxin (30 mg/kg of lipopolysaccharide, i.v.). Erythro-9[2-hydroxyl-3-nonyl] adenine (EHNA; an adenosine deaminase inhibitor) had no effects on measured time-pressure variables of heart performance under baseline conditions and during endotoxemia, yet significantly attenuated endotoxin-induced release of cytokines and PRA. Pretreatment with the non-selective adenosine receptor antagonist DPSPX not only prevented the effects of EHNA but also increased the basal release of cytokines and augmented PRA. At baseline, caffeine (a non-selective adenosine receptor antagonist) increased HR, +dP/dtmax, heart rate x ventricular pressure product (HR x VPSP) and +dP/dtmax normalized by pressure (+dP/dtmax/VPSP), and these changes persisted during endotoxemia. Caffeine attenuated endotoxin-induced release of cytokines and augmented endotoxin-induced increases in plasma catecholamines and PRA. Pretreatment with propranolol abolished the effects of caffeine on heart performance and neurohumoral activation during the early phase of endotoxemia. 6N-cyclopentyladenosine (CPA; selective A1 adenosine receptor agonist) induced bradicardia and negative inotropic effects, reduced work load (i.e., decreased HR, VPSP, +dP/dtmax, +dP/dtmax/VPSP and HR x VPSP) and inhibited endotoxin-induced tachycardia and renin release. CGS 21680 (selective A2A adenosine receptor agonist) decreased blood pressure under basal condition but did not potentiate decreases in blood pressure

  14. Estimation of compressional seismic wave attenuation of carbonate rocks in Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Bouchaala, Fateh; Ali, Mohammed Y.; Farid, Asam

    2014-07-01

    The subsurface geology of Abu Dhabi in the United Arab Emirates is primarily composed of carbonate rocks. Such media are known to be highly heterogeneous. Very few studies have attempted to estimate attenuation in carbonate rocks. In Abu Dhabi no attenuation profile has been published. This study provides the first seismic wave attenuation profiles in Abu Dhabi using dense array of VSP data. We estimated three attenuation profiles: the apparent, the scattering, and the intrinsic attenuations. The apparent attenuation profile was computed using amplitude decay and spectral-ratio methods. The scattering attenuation profile was estimated using a generalized reflection-transmission matrix forward model. It is usually estimated from the sonic log, but to be more consistent with the apparent attenuation, we succeeded in this paper to estimate it from the VSP data. We subtracted the scattering attenuation from the apparent attenuation to deduce the intrinsic attenuation. The results of the study indicate that the scattering attenuation is significant compared to the published studies that are mainly based on clastic rocks. The high scattering attenuation can reach up to 0.02. It can be explained by the strong heterogeneity of the carbonate rocks. This study demonstrates that the Simsima and Rus Formations have considerable scattering and intrinsic attenuations. These formations are considered aquifers in Abu Dhabi; we therefore interpreted this high intrinsic attenuation zones to be due to the heterogeneity and to the fluids contained in these formations. The Umm-Er-Radhuma Formation is a more homogenous formation with limited aquifer potential. Hence, scattering and intrinsic attenuations of the Umm-Er-Radhuma Formation are low.

  15. Autism: Why Act Early?

    Science.gov (United States)

    ... What's this? Submit Button Past Emails CDC Features Autism: Why Act Early? Language: English Español (Spanish) Recommend ... helped the world make sense." Florida teenager with Autism Spectrum Disorder "Because my parents acted early, I ...

  16. Cancer treatment -- early menopause

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000912.htm Cancer treatment - early menopause To use the sharing features on this page, please enable JavaScript. Certain types of cancer treatments can cause women to have early menopause. This ...

  17. Overview of Early Intervention

    Science.gov (United States)

    ... infant or toddler for early intervention (e.g., Down syndrome, Fragile X syndrome). Determining eligibility | The results of the evaluation will be used to determine your child’s eligibility for early intervention services. You and a ...

  18. Early Retirement Programs.

    Science.gov (United States)

    Everett, Peter W.

    1984-01-01

    Early retirement programs offer individuals an alternative to the work ethic while allowing them to maintain job security. Examples are given of several early, partial, and phased retirement programs currently being used in universities and public school systems. (DF)

  19. Earth-To-Space Improved Model for Rain Attenuation Prediction at Ku-Band

    Directory of Open Access Journals (Sweden)

    Mandeep S.J. Singh

    2006-01-01

    Full Text Available A model for predicting rain attenuation on earth-to-space was developed by using the measurement data obtained from tropical and equatorial region. The proposed rain attenuation model uses the complete rainfall rate cumulative distribution as input data. It was shown that significant improvements in terms of prediction error over existing attenuation model obtained.

  20. Physiological and Antigenic Characteristics of Virulent and Attenuated Strains of Legionella pneumophila (Philadelphia 3)

    Science.gov (United States)

    1981-07-01

    CHARACTERISTICS OF I, VIRULENT AND ATTENUATED5TRAINS OF LEGIONELLA Interim PNEUMOPHILA (PHILADELPHIA 3) 6 . PERFORMING ORG. REPORT NUMBER 70 AUTHOR(*) B...number) Several methods were used to cJvrtcterize selected virulent and attenuated strains of Legionella pneumophila serogroup 1. The cultural...Antigenic Characteristics of Virulent and Attenuated Strains of Legionella pneumophila (Philadelphia 3) JOSEPH D. RISTROPH, KENNETH W. HEDLUND, AND

  1. Attenuation correction for X-ray emission computed tomography of laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yen-Wei; Nakao, Zensho [Ryukyus Univ., Nishihara, Okinawa (Japan). Faculty of Engineering; Tamura, Shinichi

    1996-08-01

    An attenuation correction method was proposed for laser-produced plasma emission computed tomography (ECT), which is based on a relation of the attenuation coefficient and the emission coefficient in plasma. Simulation results show that the reconstructed images are dramatically improved in comparison to the reconstructions without attenuation correction. (J.P.N.)

  2. Attenuation of vacuum ultraviolet light in liquid argon

    CERN Document Server

    Neumeier, A; Oberauer, L; Potzel, W; Schönert, S; Dandl, T; Heindl, T; Ulrich, A; Wieser, J

    2015-01-01

    The transmission of liquid argon has been measured, wavelength resolved, for a wavelength interval from 118 to 250 nm. The wavelength dependent attenuation length is presented for pure argon. It is shown that no universal wavelength independent attenuation length can be assigned to liquid argon for its own fluorescence light due to the interplay between the wavelength dependent emission and absorption. A decreasing transmission is observed below 130 nm in both chemically cleaned and distilled liquid argon and assigned to absorption by the analogue of the first argon excimer continuum. For not perfectly cleaned argon a strong influence of impurities on the transmission is observed. Two strong absorption bands at 126.5 and 141.0 nm with approximately 2 and 4 nm width, respectively, are assigned to traces of xenon in argon. A broad absorption region below 180 nm is found for unpurified argon and tentatively attributed to the presence of water in the argon sample.

  3. Attenuation measurements of vacuum ultraviolet light in liquid argon revisited

    Energy Technology Data Exchange (ETDEWEB)

    Neumeier, A. [Physik-Department E15, Technische Universität München, James-Franck-Straße 1, 85748 Garching (Germany); Dandl, T.; Himpsl, A. [Physik-Department E12, Technische Universität München, James-Franck-Straße 1, 85748 Garching (Germany); Hofmann, M. [Physik-Department E15, Technische Universität München, James-Franck-Straße 1, 85748 Garching (Germany); KETEK GmbH, Hofer Straße 3, 81737 München (Germany); Oberauer, L.; Potzel, W.; Schönert, S. [Physik-Department E15, Technische Universität München, James-Franck-Straße 1, 85748 Garching (Germany); Ulrich, A., E-mail: andreas.ulrich@ph.tum.de [Physik-Department E12, Technische Universität München, James-Franck-Straße 1, 85748 Garching (Germany)

    2015-11-11

    The attenuation of vacuum ultraviolet light in liquid argon in the context of its application in large liquid noble gas detectors has been studied. Compared to a previous publication several technical issues concerning transmission measurements in general are addressed and several systematic effects were quantitatively measured. Wavelength-resolved transmission measurements have been performed from the vacuum ultraviolet to the near-infrared region. On the current level of sensitivity with a length of the optical path of 11.6 cm, no xenon-related absorption effects could be observed, and pure liquid argon is fully transparent down to the short wavelength cut-off of the experimental setup at 118 nm. A lower limit for the attenuation length of pure liquid argon for its own scintillation light has been estimated to be 1.10 m based on a very conservative approach.

  4. Attenuation measurements of vacuum ultraviolet light in liquid argon revisited

    CERN Document Server

    Neumeier, A; Himpsl, A; Hofmann, M; Oberauer, L; Potzel, W; Schönert, S; Ulrich, A

    2015-01-01

    The attenuation of vacuum ultraviolet light in liquid argon in the context of its application in large liquid noble gas detectors has been studied. Compared to a previous publication several technical issues concerning transmission measurements in general are addressed and several systematic effects were quantitatively measured. Wavelength-resolved transmission measurements have been performed from the vacuum ultraviolet to the near-infrared region. On the current level of sensitivity with a length of the optical path of 11.6 cm, no xenon-related absorption effects could be observed, and pure liquid argon is fully transparent down to the short wavelength cut-off of the experimental setup at 118 nm. A lower limit for the attenuation length of pure liquid argon for its own scintillation light has been estimated to be 1.10 m based on a very conservative approach.

  5. Dust Attenuation in Hydrodynamic Simulations of Spiral Galaxies

    CERN Document Server

    Rocha, M; Primack, J R; Cox, T J; Rocha, Miguel; Jonsson, Patrik; Primack, Joel R.

    2007-01-01

    We study the effects of dust in hydrodynamic simulations of spiral galaxies when different radial metallicity gradients are assumed. SUNRISE, a Monte-Carlo radiative-transfer code, is used to make detailed calculations of the internal extinction of disk galaxies caused by their dust content. SUNRISE is used on eight different Smooth Particle Hydrodynamics (SPH) simulations of isolated spiral galaxies. These galaxies vary mainly in mass and hence luminosity, spanning a range in luminosities from -16 to -22 magnitudes in the B band. We focus on the attenuation in different wavelength bands as a function of the disk inclination and the luminosity of the models, and compare this to observations. Observations suggest different metallicity gradients for galaxies of different luminosities. These metallicity gradients were explored in our different models, finding that the resulting dust attenuation matches observations for edge-on galaxies, but do not show a linear behaviour in log axis ratio as some observations ha...

  6. A novel live-attenuated vaccine candidate for mayaro Fever.

    Science.gov (United States)

    Weise, William J; Hermance, Meghan E; Forrester, Naomi; Adams, A Paige; Langsjoen, Rose; Gorchakov, Rodion; Wang, Eryu; Alcorn, Maria D H; Tsetsarkin, Konstantin; Weaver, Scott C

    2014-08-01

    Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  7. Nutrient attenuation in rivers and streams, Puget Sound Basin, Washington

    Science.gov (United States)

    Sheibley, Rich W.; Konrad, Christopher P.; Black, Robert W.

    2015-01-01

    Nutrients such as nitrogen and phosphorus are important for aquatic ecosystem health. Excessive amounts of nutrients, however, can make aquatic ecosystems harmful for biota because enhanced growth and decay cycles of aquatic algae can reduce dissolved oxygen in the water. In Puget Sound marine waters, low dissolved oxygen concentrations are observed in a number of marine nearshore areas, and nutrients have been identified as a major stressor to the local ecosystem. Delivery of nutrients from major rivers in the Puget Sound Basin to the marine environment can be large. Therefore, it is important to identify factors related to how nutrients are retained (attenuated) within streams and rivers in the Puget Sound Basin. Physical, chemical, and biological factors related to nutrient attenuation were identified through a review of related scientific literature.

  8. Numerical support of laboratory experiments: Attenuation and velocity estimations

    Science.gov (United States)

    Saenger, Erik; Madonna, Claudio; Frehner, Marcel; Almqvist, Bjarne

    2014-02-01

    We show that numerical support of laboratory experiments can significantly increase the understanding and simplify the interpretation of the obtained laboratory results. First we perform simulations of the Seismic Wave Attenuation Module to measure seismic attenuation of reservoir rocks. Our findings confirm the accuracy of this system. However, precision can be further improved by optimizing the sensor positions. Second, we model wave propagation for an ultrasonic pulse transmission experiment used to determine pressure- and temperature-dependent seismic velocities in the rock. Multiple waves are identified in our computer experiment, including bar waves. The metal jacket that houses the sample assembly needs to be taken into account for a proper estimation of the ultrasonic velocities. This influence is frequency-dependent.

  9. A novel live-attenuated vaccine candidate for mayaro Fever.

    Directory of Open Access Journals (Sweden)

    William J Weise

    2014-08-01

    Full Text Available Mayaro virus (MAYV is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  10. Wave attenuation model for dephasing and measurement of conditional times

    Indian Academy of Sciences (India)

    A M Jayannavar; Colin Benjamin

    2002-08-01

    Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering in such systems is presented and a relatively new model based on wave attenuation is introduced. The problem of Aharonov–Bohm (AB) oscillations in conductance of a mesoscopic ring is studied. We show that the conductance is symmetric under flux reversal and the visibility of AB oscillations decays to zero as a function of the incoherence parameter, signaling dephasing. Further the wave attenuation model is applied to a fundamental problem in quantum mechanics, that of the conditional (reflection/transmission) times spent in a given region of space by a quantum particle before scattering off from that region.

  11. Velocity and attenuation of sound in arterial tissues

    Science.gov (United States)

    Rooney, J. A.; Gammell, P. M.; Hestenes, J. D.; Chin, H. P.; Blankenhorn, D. H.

    1982-01-01

    The velocity of sound in excised human and canine arterial tissues is measured in order to serve as a basis for the development and application of ultrasonic techniques for the diagnosis of atherosclerotic lesions. Measurements of sound velocity at different regions of 11 human and six canine aortas were made by a time delay spectrometer technique at frequencies from 2 to 10 MHz, and compared with ultrasonic attenuation parameters and the results of biochemical assays. Sound velocity is found to increase with increasing attenuation at all frequencies, and with increasing collagen content. A strong dependence of sound velocity on cholesterol content or low calcium contents is not observed, although velocities of up to 2000 m/sec are observed in highly organized calcified lesions. A decrease in velocity with decreasing temperature is also noted. It is thus concluded that it is principally the differences in tissue collagen levels that contribute to image formation according to sound velocity.

  12. Anatomy of the TAMA SAS seismic attenuation system

    CERN Document Server

    Marka, S; Ando, M; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Wang Chen Yang; Yamamoto, H; Yoda, T

    2002-01-01

    The TAMA SAS seismic attenuation system was developed to provide the extremely high level of seismic isolation required by the next generation of interferometric gravitational wave detectors to achieve the desired sensitivity at low frequencies. Our aim was to provide good performance at frequencies above approx 10 Hz, while utilizing only passive subsystems in the sensitive frequency band of the TAMA interferometric gravitational wave detectors. The only active feedback is relegated below 6 Hz and it is used to damp the rigid body resonances of the attenuation chain. Simulations, based on subsystem performance characterizations, indicate that the system can achieve rms mirror residual motion measured in a few tens of nanometres. We will give a brief overview of the subsystems and point out some of the characterization results, supporting our claims of achieved performance. SAS is a passive, UHV compatible and low cost system. It is likely that extremely sensitive experiments in other fields will also profit ...

  13. Attenuation of rare earth elements in a boreal estuary

    Science.gov (United States)

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

    2012-11-01

    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 μm) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  14. Experimental and theoretical studies on visible light attenuation in water

    CERN Document Server

    Simpson, A; Cho, H J; Liu, H

    2014-01-01

    In this study we describe lab experiments on determining the above water reflectance Rrs coefficient, and the water attenuation coefficient Kd for fresh water. Different types of screens (totally absorbent, gray, etc.) were submerged in water (0-0.6 m) and illuminated from outside. The spectral density of the water leaving radiance was measured for different depths. The results were ran by a code which took into account the geometry of the incident irradiation, the geometry of the screen under water, and boundary conditions at the water surface provided by the radiation transfer theory. From the experimental data and our model we obtain the spectral distribution of the attenuation coefficient for fresh water and compared it with other data in literature. These experiments, performed in the Nonlinear Wave Lab at ERAU# represent just a preliminary calibration of the experimental protocol. More tests with water of different degrees of turbidity, and possibly wave filed at the water surface are in progress and wi...

  15. Random seismic noise attenuation using the Wavelet Transform

    Science.gov (United States)

    Aliouane, L.; Ouadfeul, S.; Boudella, A.; Eladj, S.

    2012-04-01

    In this paper we propose a technique of random noises attenuation from seismic data using the discrete and continuous wavelet transforms. Firstly the discrete wavelet transform (DWT) is applied to denoise seismic data. This last is based on the threshold method applied at the modulus of the DWT. After we calculate the continuous wavelet transform of the denoised seismic seismogram, the final denoised seismic seismogram is the continuous wavelet transform coefficients at the low scale. Application at a synthetic seismic seismogram shows the robustness of the proposed tool for random noises attenuation. We have applied this idea at a real seismic data of a vertical seismic profile realized in Algeria. Keywords: Seismic data, denoising, DWT, CWT, random noise.

  16. Propagation and Attenuation Characteristics of Diesel Particulate Filter

    Institute of Scientific and Technical Information of China (English)

    GAO Wenzhi; SONG Chonglin; LIU Jianguo; GUAN Shunji

    2005-01-01

    Diesel particulate filter (DPF) is an important factor which influences the sound from exhaust system of an engine. In order to understand the propagation law of sound wave and predict the insertion loss in DPF, based on the general aero-dynamic equations and Darcy′s law, an acoustic property calculation model of DPF is constructed. Propagation and attenuation characteristics of the forward and backward propagating acoustic waves in the close and open pipe of the filter are investigated. The theoretical model is combined with experiment to investigate sound attenuation property of DPF. The insertion loss obtained from the experiment is compared with that computed for a DPF. The results from the experiment and theoretical calculation agree well.

  17. Electroacupuncture attenuates neuropathic pain after brachial plexus injury

    Institute of Scientific and Technical Information of China (English)

    Shenyu Zhang; Hailiang Tang; Junming Zhou; Yudong Gu

    2014-01-01

    Electroacupuncture has traditionally been used to treat pain, but its effect on pain following brachial plexus injury is still unknown. In this study, rat models of an avulsion injury to the left brachial plexus root (associated with upper-limb chronic neuropathic pain) were given electroacu-puncture stimulation at bilateralQuchi(LI11),Hegu(LI04),Zusanli(ST36) andYanglingquan (GB34). After electroacupuncture therapy, chronic neuropathic pain in the rats’ upper limbs was signiifcantly attenuated. Immunolfuorescence staining showed that the expression of β-endorphins in the arcuate nucleus was signiifcantly increased after therapy. Thus, experimental ifndings indi-cate that electroacupuncture can attenuate neuropathic pain after brachial plexus injury through upregulatingβ-endorphin expression.

  18. Depolarization and attenuation effects of radomes at 20 GHz

    Science.gov (United States)

    Hendrix, Charles E.; McNally, James E.; Monzingo, Robert A.

    1989-03-01

    The problem of describing the attenuation and depolarization effects of a wet radome on a transmitted signal is considered by experiments carried out with two commonly used radome materials, ESSCOLAM-6 and ESSCOLAM-8. The results suggest that a two-component model of depolarization is required to account for the observed results. Predictions for the behavior of a complete radome are obtained, but full-scale testing with an operating radome to compare predicted and actual results remains to be done. An important conclusion is that, while highly water-repellent radome materials are desirable from the point of view of attenuation, they are not so desirable in terms of the degree of depolarization introduced between orthogonally polarized signal components in frequency-reuse systems.

  19. NATURAL ATTENUATION FOR ECOSYSTEM RESTORATION IN NY/NJ HARBOR

    Energy Technology Data Exchange (ETDEWEB)

    Van der Lelie, D.; Reid-Green, J. D.; Stern, E. A.

    2003-12-31

    We have investigated the feasibility of using natural attenuation methods for ecosystem restoration in New York/New Jersey Harbor. Measurements were made of the most probable number of sulfate-reducing bacteria (SRB) in native sediments and in samples, which had been supplemented with an appropriate electron donor and electron acceptor. The results showed that the activity of the endogenous microbial population in the native sediment was high enough to make possible adequate chemical transformation rates. The bioavailability of the zinc in the sediments was measured using the BIOMET biosensor technique. The bioavailability of the zinc was effectively eliminated following the microbial activities. We concluded that natural attenuation could be used effectively in treating sediments from Newark Bay and surrounding waters and that the resultant materials could likely be used in environmental restoration projects of the type proposed for construction in South Kearny, NJ.

  20. Towards ISS disturbance attenuation for randomly switched systems

    CERN Document Server

    Chatterjee, Debasish

    2007-01-01

    We are concerned with input-to-state stability (ISS) of randomly switched systems. We provide preliminary results dealing with sufficient conditions for stochastic versions of ISS for randomly switched systems without control inputs, and with the aid of universal formulae we design controllers for ISS-disturbance attenuation when control inputs are present. Two types of switching signals are considered: the first is characterized by a statistically slow-switching condition, and the second by a class of semi-Markov processes.

  1. Peripheral δ-opioid receptors attenuate the exercise pressor reflex.

    Science.gov (United States)

    Leal, Anna K; Yamauchi, Katsuya; Kim, Joyce; Ruiz-Velasco, Victor; Kaufman, Marc P

    2013-10-15

    In rats with ligated femoral arteries, the exercise pressor reflex is exaggerated, an effect that is attenuated by stimulation of peripheral μ-opioid receptors on group IV metabosensitive afferents. In contrast, δ-opioid receptors are expressed mostly on group III mechanosensitive afferents, a finding that prompted us to determine whether stimulation of these opioid receptors could also attenuate the exaggerated exercise pressor reflex in "ligated" rats. We found femoral arterial injection of [D-Pen2,D-Pen5]enkephalin (DPDPE; 1.0 μg), a δ-opioid agonist, significantly attenuated the pressor and cardioaccelerator components of the exercise pressor reflex evoked by hindlimb muscle contraction in both rats with ligated and patent femoral arteries. DPDPE significantly decreased the pressor responses to muscle mechanoreflex activation, evoked by tendon stretch, in ligated rats only. DPDPE (1.0 μg) had no effect in either group on the pressor and cardioaccelerator responses to capsaicin (0.2 μg), which primarily stimulates group IV afferents. DPDPE (1.0 μg) had no effect on the pressor and cardioaccelerator responses to lactic acid (24 mM), which stimulates group III and IV afferents, in rats with patent femoral arteries but significantly decreased the pressor response in ligated rats. Western blots revealed the amount of protein comprising the δ-opioid receptor was greater in dorsal root ganglia innervating hindlimbs with ligated femoral arteries than in dorsal root ganglia innervating hindlimbs with patent femoral arteries. Our findings support the hypothesis that stimulation of δ-opioid receptors on group III afferents attenuated the exercise pressor reflex.

  2. Caffeine attenuates scopolamine-induced memory impairment in humans.

    Science.gov (United States)

    Riedel, W; Hogervorst, E; Leboux, R; Verhey, F; van Praag, H; Jolles, J

    1995-11-01

    Caffeine consumption can be beneficial for cognitive functioning. Although caffeine is widely recognized as a mild CNS stimulant drug, the most important consequence of its adenosine antagonism is cholinergic stimulation, which might lead to improvement of higher cognitive functions, particularly memory. In this study, the scopolamine model of amnesia was used to test the cholinergic effects of caffeine, administered as three cups of coffee. Subjects were 16 healthy volunteers who received 250 mg caffeine and 2 mg nicotine separately, in a placebo-controlled double-blind cross-over design. Compared to placebo, nicotine attenuated the scopolamine-induced impairment of storage in short-term memory and attenuated the scopolamine-induced slowing of speed of short-term memory scanning. Nicotine also attenuated the scopolamine-induced slowing of reaction time in a response competition task. Caffeine attenuated the scopolamine-induced impairment of free recall from short- and long-term memory, quality and speed of retrieval from long-term memory in a word learning task, and other cognitive and non-cognitive measures, such as perceptual sensitivity in visual search, reading speed, and rate of finger-tapping. On the basis of these results it was concluded that caffeine possesses cholinergic cognition enhancing properties. Caffeine could be used as a control drug in studies using the scopolamine paradigm and possibly also in other experimental studies of cognitive enhancers, as the effects of a newly developed cognition enhancing drug should at least be superior to the effects of three cups of coffee.

  3. Scatter and attenuation correction in Technetium-99m brain SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Jun [Keio Univ., Tokyo (Japan). School of Medicine

    1997-11-01

    The imaging in the nuclear medicine is inferior to other modalities in the spatial resolution, but it can quantitatively evaluate the biological function. The attempt to measure the absolute or the relative values of local functions quantitatively based on the SPECT of the brain or the heart, has become popular recently. It is not only necessary to introduce an appropriate analytical model for each radioisotope tracer for the correct quantification, but also to be equipped with the photographing system to measure correctly the accumulation of the tracer. The main cause to decrease the precision of the photographing system is the scatter and the absorption (attenuation) of photon. In the present study we attempted to enhance the quantification of the brain SPECT by the usable and practical correction method for the scatter and the attenuation in the daily clinical business. We used the triple-energy-window (TEW) method as the scatter correction and the attenuation calculation map obtained from the transmission scanning (TCT) by the external source as the attenuation correction. We examined the brain SPECT in combination with these two correction methods. We could not measure correctly the amount of the tracer accumulation by only one correction method, and obtain the excellent quantitative SPECT images in combination with both correction methods. We could get excellently stable data by collecting the emission and the transmission data simultaneously as well as separately, and the excellent images by the arithmetical treatment of data between the scatter beam and the detector correction when we used {sup 99m}Tc as the source which is economically cheap, and adopted the combination of the tracers labeled by the same kind of radioisotopes. Altogether we expect that our method is very practical and will contribute to enhance the accuracy in quantitative analysis of clinical brain SPECT imaging. (K.H.)

  4. Training on hearing protector insertion improves noise attenuation

    OpenAIRE

    Samelli, Alessandra Giannella; Rocha,Clayton Henrique; Theodósio,Patrícia; Moreira,Renata Rodrigues; Neves-Lobo,Ivone Ferreira

    2015-01-01

    ABSTRACT Purpose: To determine the efficacy of hearing protector insertion by comparing attenuation values measured by objective (MIRE) and subjective (REAT) methods in groups with and without training. Methods: The study included 80 male subjects assigned to experimental (with training) and control (without training) groups. The following procedures were performed: occupational history, objective and subjective assessment of hearing protectors. Only subjects in the experimental group rece...

  5. Mode-dependent attenuation of optical fibers: excess loss.

    Science.gov (United States)

    Olshansky, R; Nolan, D A

    1976-04-01

    A theory is presented for calculating the excess loss produced by random perturbations of optical fibers. The theory is applicable to perturbations whose longitudinal spatial frequencies are below the range required for mode coupling. To illustrate the method, losses due to diameter variations are calculated for the case of a step-index optical fiber. The diameter variations are found to produce a strong attenuation of the higher order modes. The total excess loss is approximately wavelength independent.

  6. Deduction of static surface roughness from complex excess attenuation.

    Science.gov (United States)

    Nichols, Andrew; Attenborough, Keith; Taherzadeh, Shahram

    2011-03-01

    Data for complex excess attenuation have been used to determine the effective surface admittance and hence characteristic roughness size of a surface comprising a random distribution of semi-cylindrical rods on an acoustically hard plane. The inversion for roughness size is based on a simplified boss model. The technique is shown to be effective to within 4%, up to a threshold roughness packing density of 32%, above which the interaction between scattering elements appears to exceed that allowed by the model.

  7. Synthetic Chemicals with Potential for Natural Attenuation (Postprint)

    Science.gov (United States)

    2012-07-01

    Distribution Code 20: JOURNAL ARTICLES; DTIC USERS ONLY. Document contains color images. Published in Bioremediation Journal 1 (1): 1-9 (1997...Natural attenuation of petroleum hydrocarbons is predictable and self-sustaining because bacteria able to use the contaminants as growth substrates are...petroleum hydrocarbons is predictable and self-sustaining because bacteria able to use the contaminants as growth substrates are widely distributed. In

  8. Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

  9. Frequently Asked Questions about Monitored Natural Attenuation in Groundwater

    Science.gov (United States)

    2014-02-01

    Technology 2001, 35(19): 3884-3891. (167) Lee, W.; Batchelor, B., Abiotic Reductive Dechlorination of Chlorinated Ethylenes by Iron-Bearing Soil...MNA was inspired by the fact that it has been over a decade since publication of Natu10l Attenuation of Fuels and Chlorinated Sol~~ents15 which was...effect, MNA is typically a component of every chlorinated -solvent site remedy. (ITRC Integrated DNAPL Strategy Guidance, 20 II, citing ITRC’s

  10. A disorder-based strategy for tunable, broadband wave attenuation

    Science.gov (United States)

    Zhang, Weiting; Celli, Paolo; Cardella, Davide; Gonella, Stefano

    2017-04-01

    One of the most daunting limitations of phononic crystals and acoustic/elastic metamaterials is their passivity: a given configuration is bound to display its phononic properties only around its design point, i.e., working at some pre-determined operating conditions. In the past decade, this shortcoming has inspired the design of phononic media with tunable wave characteristics; noteworthy results have been obtained through a family of methodologies involving shunted piezoelectric elements. Shunting a piezoelectric element means connecting it to a passive electric circuit; tunability stems from the ability to modify the effective mechanical properties of the piezoelectric medium by modifying the circuit characteristics. One of the most popular shunting circuits is the resistor-inductor, which allows the patch-and-shunt system to behave as an electromechanical resonator. A common motif among the works employing shunted piezos for phononic control is periodicity: the patches are typically periodically placed in the domain and the circuits are identically tuned. The objective of this work is to demonstrate that the wave attenuation performance of structures with shunted piezoelectric patches can be improved by leveraging notions of organized disorder. Based on the idea of rainbow trapping broadband wave attenuation obtained by tuning an array of resonators at distinct neighboring frequencies we design and test an electromechanical waveguide structure capable of attenuating waves over broad frequency ranges. In order to emphasize the fact that periodicity is not a binding requirement when working with RL shunts (which induce locally resonant bandgaps), we report on the performance of random arrangements of patches. In an attempt to demonstrate the tunability attribute of our strategy, we take advantage of the reconfigurability of the circuits to show how a single waveguide can attenuate both waves and vibrations over different frequency ranges.

  11. Genetically attenuated Trypanosoma cruzi parasites as a potential vaccination tool

    OpenAIRE

    2012-01-01

    Chagas disease is the clinical manifestation of the infection produced by the parasite Trypanosoma cruzi. Currently there is no vaccine to prevent this disease and the protection attained with vaccines containing non-replicating parasites is limited. Genetically attenuated trypanosomatid parasites can be obtained by deletion of selected genes. Gene deletion takes advantage of the fact that this parasite can undergo homologous recombination between endogenous and foreign DNA sequences artifici...

  12. The Attribute for Hydrocarbon Prediction Based on Attenuation

    Science.gov (United States)

    Hermana, Maman; Harith, Z. Z. T.; Sum, C. W.; Ghosh, D. P.

    2014-03-01

    Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further.

  13. Mesenchymal dental pulp cells attenuate dentin resorption in homeostasis.

    Science.gov (United States)

    Zheng, Y; Chen, M; He, L; Marão, H F; Sun, D M; Zhou, J; Kim, S G; Song, S; Wang, S L; Mao, J J

    2015-06-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  14. Dapagliflozin, SGLT2 Inhibitor, Attenuates Renal Ischemia-Reperfusion Injury

    OpenAIRE

    Yoon-Kyung Chang; Hyunsu Choi; Jin Young Jeong; Ki-Ryang Na; Kang Wook Lee; Beom Jin Lim; Dae Eun Choi

    2016-01-01

    Dapagliflozin, a new type of drug used to treat diabetes mellitus (DM), is a sodium/glucose cotransporter 2 (SGLT2) inhibitor. Although some studies showed that SGLT2 inhibition attenuated reactive oxygen generation in diabetic kidney the role of SGLT2 inhibition is unknown. We evaluated whether SLT2 inhibition has renoprotective effects in ischemia-reperfusion (IR) models. We evaluated whether dapagliflozin reduces renal damage in IR mice model. In addition, hypoxic HK2 cells were treated wi...

  15. Advanced reconstruction of attenuation maps using SPECT emission data only

    Science.gov (United States)

    Salomon, André; Goedicke, Andreas; Aach, Til

    2009-02-01

    Today, attenuation corrected SPECT, typically performed using CT or Gadolinium line source based transmission scans, is more and more becoming standard in many medical applications. Moreover, the information about the material density distribution provided by these scans is key for other artifact compensation approaches in advanced SPECT reconstruction. Major drawbacks of these approaches are the additional patient radiation and hardware/maintenance costs as well as the additional workflow effort, e.g. if the CT scans are not performed on a hybrid scanner. It has been investigated in the past, whether it is possible to recover this structural information solely from the SPECT scan data. However, the investigated methods often result in noticeable image artifacts due to cross-dependences between attenuation and activity distribution estimation. With the simultaneous reconstruction method presented in this paper, we aim to effectively prevent these typical cross-talk artifacts using a-priori known atlas information of a human body. At first, an initial 3D shape model is coarsely registered to the SPECT data using anatomical landmarks and each organ structure within the model is identified with its typical attenuation coefficient. During the iterative reconstruction based on a modified ML-EM scheme, the algorithm simultaneously adapts both, the local activity estimation and the 3D shape model in order to improve the overall consistency between measured and estimated sinogram data. By explicitly avoiding topology modifications resulting in a non-anatomical state, we ensure that the estimated attenuation map remains realistic. Several tests with simulated as well as real patient SPECT data were performed to test the proposed algorithm, which demonstrated reliable convergence behaviour in both cases. Comparing the achieved results with available reference data, an overall good agreement for both cold as well as hot activity regions could be observed (mean deviation: -5.98%).

  16. Cavity Attenuated Phase Shift (CAPS) Monitor Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    The CAPS PMex monitor is a cavity attenuated phase shift extinction instrument. It operates as an optical extinction spectrometer, using a visible-light-emitting diode (LED) as the light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector. Its efficacy is based on the fact that aerosols are broadband scatterers and absorbers of light.

  17. Acetazolamide Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus.

    Science.gov (United States)

    de Groot, Theun; Sinke, Anne P; Kortenoeven, Marleen L A; Alsady, Mohammad; Baumgarten, Ruben; Devuyst, Olivier; Loffing, Johannes; Wetzels, Jack F; Deen, Peter M T

    2016-07-01

    To reduce lithium-induced nephrogenic diabetes insipidus (lithium-NDI), patients with bipolar disorder are treated with thiazide and amiloride, which are thought to induce antidiuresis by a compensatory increase in prourine uptake in proximal tubules. However, thiazides induced antidiuresis and alkalinized the urine in lithium-NDI mice lacking the sodium-chloride cotransporter, suggesting that inhibition of carbonic anhydrases (CAs) confers the beneficial thiazide effect. Therefore, we tested the effect of the CA-specific blocker acetazolamide in lithium-NDI. In collecting duct (mpkCCD) cells, acetazolamide reduced the cellular lithium content and attenuated lithium-induced downregulation of aquaporin-2 through a mechanism different from that of amiloride. Treatment of lithium-NDI mice with acetazolamide or thiazide/amiloride induced similar antidiuresis and increased urine osmolality and aquaporin-2 abundance. Thiazide/amiloride-treated mice showed hyponatremia, hyperkalemia, hypercalcemia, metabolic acidosis, and increased serum lithium concentrations, adverse effects previously observed in patients but not in acetazolamide-treated mice in this study. Furthermore, acetazolamide treatment reduced inulin clearance and cortical expression of sodium/hydrogen exchanger 3 and attenuated the increased expression of urinary PGE2 observed in lithium-NDI mice. These results show that the antidiuresis with acetazolamide was partially caused by a tubular-glomerular feedback response and reduced GFR. The tubular-glomerular feedback response and/or direct effect on collecting duct principal or intercalated cells may underlie the reduced urinary PGE2 levels with acetazolamide, thereby contributing to the attenuation of lithium-NDI. In conclusion, CA activity contributes to lithium-NDI development, and acetazolamide attenuates lithium-NDI development in mice similar to thiazide/amiloride but with fewer adverse effects.

  18. Pleural effusion: characterization with CT attenuation values and CT appearance.

    Science.gov (United States)

    Abramowitz, Yigal; Simanovsky, Natalia; Goldstein, Michael S; Hiller, Nurith

    2009-03-01

    The purpose of this study was to assess the utility of CT in characterizing pleural effusions on the basis of attenuation values and CT appearance. We retrospectively analyzed 100 pleural effusions in patients who underwent chest CT and diagnostic thoracentesis within 48 hours of each other. On the basis of Light's criteria, effusions were classified as exudates or transudates using laboratory biochemistry markers. The mean value in Hounsfield units of an effusion was determined using a region of interest on the three slices with the greatest quantity of fluid. All CT scans also were reviewed for the presence of additional pleural features such as fluid loculation, pleural thickening, and pleural nodules. Twenty-two of the 100 pleural effusions were transudates and 78 were exudates. The mean attenuation of the exudates (7.2 HU; [SD] 9.4 HU; range, 21-28 HU) was not significantly lower than the mean attenuation of the transudates (10.1 HU; 6.9 HU; range, 0.3-32 HU), (p = 0.24). None of the additional CT features accurately differentiated exudates from transudates (p > 0.1). Fluid loculation was found in 58% of exudates and in 36% of transudates. Pleural thickening was found in 59% of exudates and in 36% of transudates. The clinical use of CT attenuation values to characterize pleural fluid is not accurate. Although fluid loculation, pleural thickness, and pleural nodules were more commonly found in patients with exudative effusions, the presence of these features does not accurately differentiate between exudates and transudates.

  19. Radiation attenuation and opacity in smoke and water sprays

    Science.gov (United States)

    Parent, Gilles; Boulet, Pascal; Morlon, Romain; Blanchard, Elizabeth

    2017-08-01

    Radiation attenuation through sprays, smoke and mixings of both media was studied in the infrared and in the visible range, by conducting real scale experiments in a corridor. The effect of water injection by a water mist nozzle and a sprinkler device was investigated. Radiation attenuation in the infrared range and opacity in the visible range were measured, by using a FTIR spectrometer and a dedicated opacimetry device especially designed for the present application. Experiments were done using either a blackbody source for attenuation characterization, or a heptane pool fire aimed at producing smoke for opacity measurements. For tests with smoke, the difficulties raised by the harsh environment involving a hot mixing of gas plus soot and vapor carrying water droplets were circumvented with an original device involving an optical fiber network. Mean infrared transmission was found equal to 12% for the water mist (with a 25 L/min water flowrate) and 37% for the sprinkler (with a 91 L/min water flowrate). Fitting the infrared transmission spectra with results obtained using a Monte Carlo simulation provided an estimation of the water volumetric fraction in the spray. It was shown that the better attenuation capability of the water mist is due to two factors: (1) a higher extinction coefficient of the water mist for a given water volumetric fraction due to the small size of the injected droplets and (2) a higher water volumetric fraction. Opacity measurements in the visible range yielded a measured extinction coefficient in good agreement with an estimation obtained with the Mie theory and the identified water volumetric fraction. Moreover, the water sprays (sprinkler or water mist) was seen to lead to a quick de-stratification of the smoke layer. When the spraying operation was stopped, the visibility re-increased in two main steps: a first step of fast increase and a second step of slow increase needing a few tens of seconds to get again a fully stratified smoke

  20. High Attenuation Rate for Shallow, Small Earthquakes in Japan

    Science.gov (United States)

    Si, Hongjun; Koketsu, Kazuki; Miyake, Hiroe

    2017-03-01

    We compared the attenuation characteristics of peak ground accelerations (PGAs) and velocities (PGVs) of strong motion from shallow, small earthquakes that occurred in Japan with those predicted by the equations of Si and Midorikawa (J Struct Constr Eng 523:63-70, 1999). The observed PGAs and PGVs at stations far from the seismic source decayed more rapidly than the predicted ones. The same tendencies have been reported for deep, moderate, and large earthquakes, but not for shallow, moderate, and large earthquakes. This indicates that the peak values of ground motion from shallow, small earthquakes attenuate more steeply than those from shallow, moderate or large earthquakes. To investigate the reason for this difference, we numerically simulated strong ground motion for point sources of M w 4 and 6 earthquakes using a 2D finite difference method. The analyses of the synthetic waveforms suggested that the above differences are caused by surface waves, which are predominant at stations far from the seismic source for shallow, moderate earthquakes but not for shallow, small earthquakes. Thus, although loss due to reflection at the boundaries of the discontinuous Earth structure occurs in all shallow earthquakes, the apparent attenuation rate for a moderate or large earthquake is essentially the same as that of body waves propagating in a homogeneous medium due to the dominance of surface waves.

  1. Natural attenuation software (NAS): Assessing remedial strategies and estimating timeframes

    Science.gov (United States)

    Mendez, E.; Widdowson, M.; Chapelle, F.; Casey, C.

    2005-01-01

    Natural Attenuation Software (NAS) is a screening tool to estimate remediation timeframes for monitored natural attenuation (MNA) and to assist in decision-making on the level of source zone treatment in conjunction with MNA using site-specific remediation objectives. Natural attenuation processes that NAS models include are advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation of either petroleum hydrocarbons or chlorinated ethylenes. Newly-implemented enhancements to NAS designed to maximize the utility of NAS for site managers were observed. NAS has expanded source contaminant specification options to include chlorinated ethanes and chlorinated methanes, and to allow for the analysis of any other user-defined contaminants that may be subject to microbially-mediated transformations (heavy metals, radioisotopes, etc.). Included is the capability to model co-mingled plumes, with constituents from multiple contaminant categories. To enable comparison of remediation timeframe estimates between MNA and specific engineered remedial actions , NAS was modified to incorporate an estimation technique for timeframes associated with pump-and-treat remediation technology for comparison to MNA. This is an abstract of a paper presented at the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

  2. Dust Attenuation in High Redshift Galaxies -- 'Diamonds in the Sky'

    CERN Document Server

    Scoville, Nick; Capak, Peter; Kakazu, Yuko; Li, Gongjie; Steinhardt, Charles

    2014-01-01

    We use observed optical to near infrared spectral energy distributions (SEDs) of 266 galaxies in the COSMOS survey to derive the wavelength dependence of the dust attenuation at high redshift. All of the galaxies have spectroscopic redshifts in the range z = 2 to 6.5. The presence of the CIV absorption feature, indicating that the rest-frame UV-optical SED is dominated by OB stars, is used to select objects for which the intrinsic, unattenuated spectrum has a well-established shape. Comparison of this intrinsic spectrum with the observed broadband photometric SED then permits derivation of the wavelength dependence of the dust attenuation. The derived dust attenuation curve is similar in overall shape to the Calzetti curve for local starburst galaxies. We also see the 2175 \\AA~bump feature which is present in the Milky Way and LMC extinction curves but not seen in the Calzetti curve. The bump feature is commonly attributed to graphite or PAHs. No significant dependence is seen with redshift between sub-sample...

  3. Static tests of excess ground attenuation at Wallops Flight Center

    Science.gov (United States)

    Sutherland, L. C.; Brown, R.

    1981-01-01

    An extensive experimental measurement program which evaluated the attenuation of sound for close to horizontal propagation over the ground was designed to replicate, under static conditions, results of the flight measurements carried out earlier by NASA at the same site (Wallops Flight Center). The program consisted of a total of 41 measurement runs of attenuation, in excess of spreading and air absorption losses, for one third octave bands over a frequency range of 50 to 4000 Hz. Each run consisted of measurements at 10 locations up to 675 m, from a source located at nominal elevations of 2.5, or 10 m over either a grassy surface or an adjacent asphalt concrete runway surface. The tests provided a total of over 8100 measurements of attenuation under conditions of low wind speed averaging about 1 m/s and, for most of the tests, a slightly positive temperature gradient, averaging about 0.3 C/m from 1.2 to 7 m. The results of the measurements are expected to provide useful experimental background for the further development of prediction models of near grazing incidence sound propagation losses.

  4. Resveratrol Attenuates Copper-Induced Senescence by Improving Cellular Proteostasis

    Science.gov (United States)

    2017-01-01

    Copper sulfate-induced premature senescence (CuSO4-SIPS) consistently mimetized molecular mechanisms of replicative senescence, particularly at the endoplasmic reticulum proteostasis level. In fact, disruption of protein homeostasis has been associated to age-related cell/tissue dysfunction and human disorders susceptibility. Resveratrol is a polyphenolic compound with proved antiaging properties under particular conditions. In this setting, we aimed to evaluate resveratrol ability to attenuate cellular senescence induction and to unravel related molecular mechanisms. Using CuSO4-SIPS WI-38 fibroblasts, resveratrol is shown to attenuate typical senescence alterations on cell morphology, senescence-associated beta-galactosidase activity, and cell proliferation. The mechanisms implicated in this antisenescence effect seem to be independent of senescence-associated genes and proteins regulation but are reliant on cellular proteostasis improvement. In fact, resveratrol supplementation restores copper-induced increased protein content, attenuates BiP level, and reduces carbonylated and polyubiquitinated proteins by autophagy induction. Our data provide compelling evidence for the beneficial effects of resveratrol by mitigating CuSO4-SIPS stressful consequences by the modulation of protein quality control systems. These findings highlight the importance of a balanced cellular proteostasis and add further knowledge on molecular mechanisms mediating resveratrol antisenescence effects. Moreover, they contribute to identifying specific molecular targets whose modulation will prevent age-associated cell dysfunction and improve human healthspan. PMID:28280523

  5. Gender differences in real-world hearing protector attenuation.

    Science.gov (United States)

    Abel, S M; Alberti, P W; Rokas, D

    1988-04-01

    This research investigated the possibility of differences in real-world attenuation attributable to gender. A total of 160 subjects, 80 males and 80 females, under the age of 45 years, and with normal hearing, were tested. Subjects were assigned to four hearing protector categories with the restriction that there were 20 males and 20 females in each group. The devices chosen for study were the E-A-R expandable foam plug, the Willson Sound Silencer premolded vinyl plug with double flange, the Bilsom Soft polyethylene encapsulated glass fiber plug, and the MSA Ear Defender (V-51R) premolded vinyl plug with single flange. Binaural headphone detection thresholds were measured in quiet with the open ear, and subsequently with protectors fitted binaurally for one-third octave noise bands centered at 250, 500, 1000, 3150 and 6300 Hz. The results indicated that attenuation scores achieved by females were less than those observed for males when the device was sold in only one size. Apart from the question of adequate sizing, for two of the insert protectors studied, mean achieved attenuation fell short of the manufacturer's specifications by as much as 18 dB, for particular frequencies tested. The relatively wide variation in scores observed for all four protectors in spite of experimenter-fit could not be accounted for by differences in either hearing threshold across subjects or by size of plug fit, for those devices available in several sizes.

  6. Static tests of excess ground attenuation at Wallops Flight Center

    Science.gov (United States)

    Sutherland, L. C.; Brown, R.

    1981-06-01

    An extensive experimental measurement program which evaluated the attenuation of sound for close to horizontal propagation over the ground was designed to replicate, under static conditions, results of the flight measurements carried out earlier by NASA at the same site (Wallops Flight Center). The program consisted of a total of 41 measurement runs of attenuation, in excess of spreading and air absorption losses, for one third octave bands over a frequency range of 50 to 4000 Hz. Each run consisted of measurements at 10 locations up to 675 m, from a source located at nominal elevations of 2.5, or 10 m over either a grassy surface or an adjacent asphalt concrete runway surface. The tests provided a total of over 8100 measurements of attenuation under conditions of low wind speed averaging about 1 m/s and, for most of the tests, a slightly positive temperature gradient, averaging about 0.3 C/m from 1.2 to 7 m. The results of the measurements are expected to provide useful experimental background for the further development of prediction models of near grazing incidence sound propagation losses.

  7. Ultrasound attenuation as a quantitative measure of fracture healing

    Science.gov (United States)

    Gheduzzi, Sabina; Humphrey, Victor F.; Dodd, Simon P.; Cunningham, James L.; Miles, Anthony W.

    2004-10-01

    The monitoring of fracture healing still relies upon the judgment of callus formation and on the manual assessment of the stiffness of the fracture. A diagnostic tool capable of quantitatively measuring healing progression of a fracture would allow the fine-tuning of the treatment regime. Ultrasound attenuation measurements were adopted as a possible method of assessing the healing process in human long bones. The method involves exciting ultrasonic waves at 200 kHz in the bone and measuring the reradiation along the bone and across the fracture zone. Seven cadaveric femora were tested in vitro in intact form and after creating a transverse fracture by sawing through the cortex. The effects of five different fracture types were investigated. A partial fracture, corresponding to a 50% cut through the cortex, a closed fracture, and fractures of widths varying between 1, 2, and 4 mm were investigated. The introduction of a fracture was found to produce a dramatic effect on the amplitude of the signal. Ultrasound attenuation was found to be sensitive to the presence of a fracture, even when the fracture was well reduced. It would therefore appear feasible to adopt attenuation across a fracture as a quantitative measurement of fracture healing.

  8. Attenuation of S wave in the crust of Ordos massif

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-gui; CHUO Yong-qing; CHEN Shu-qing; JIN Chun-hua

    2005-01-01

    We presented attenuation characteristics of S waves in the crust of Ordos massif. Using 487 pieces of digital oscillograms of 19 seismic events recorded by 32 seismologic stations located on Ordos massif and its surroundings, we have calculated the parameter of three-segment geometric attenuation and give the relation of inelastic attenuation Q value with frequency in the crust of Ordos massif, site responses of 32 stations, and source parameters of 19 events by the genetic algorithm. The results indicate that Q value (at 1 Hz) of S-wave in the crust of Ordos massif is much larger than that in the geologically active tectonic region. The site responses of the 32 stations in the high-frequency section do not show clear amplification effect except one or two stations, while in the low-frequency section, there is difference among the stations. The logarithmic value of seismic moment and the magnitude ML of 19 seismic events has a very good linear relationship.

  9. Simulating atmospheric free-space optical propagation: rainfall attenuation

    Science.gov (United States)

    Achour, Maha

    2002-04-01

    With recent advances and interest in Free-Space Optics (FSO) for commercial deployments, more attention has been placed on FSO weather effects and the availability of global weather databases. The Meteorological Visual Range (Visibility) is considered one of the main weather parameters necessary to estimate FSO attenuation due to haze, fog and low clouds. Proper understanding of visibility measurements conducted throughout the years is essential. Unfortunately, such information is missing from most of the databases, leaving FSO players no choice but to use the standard visibility equation based on 2% contrast and other assumptions on the source luminance and its background. Another challenge is that visibility is measured using the visual wavelength of 550 nm. Extrapolating the measured attenuations to longer infrared wavelengths is not trivial and involves extensive experimentations. Scattering of electromagnetic waves by spherical droplets of different sizes is considered to simulate FSO scattering effects. This paper serves as an introduction to a series of publications regarding simulation of FSO atmospheric propagation. This first part focuses on attenuation due to rainfall. Additional weather parameters, such as rainfall rate, temperature and relative humidity are considered to effectively build the rain model. Comparison with already published experimental measurement is performed to validate the model. The scattering cross section due to rain is derived from the density of different raindrop sizes and the raindrops fall velocity is derived from the overall rainfall rate. Absorption due the presence of water vapor is computed using the temperature and relative humidity measurements.

  10. Adaptation with disturbance attenuation in nonlinear control systems

    Energy Technology Data Exchange (ETDEWEB)

    Basar, T. [Univ. of Illinois, Urbana, IL (United States)

    1997-12-31

    We present an optimization-based adaptive controller design for nonlinear systems exhibiting parametric as well as functional uncertainty. The approach involves the formulation of an appropriate cost functional that places positive weight on deviations from the achievement of desired objectives (such as tracking of a reference trajectory while the system exhibits good transient performance) and negative weight on the energy of the uncertainty. This cost functional also translates into a disturbance attenuation inequality which quantifies the effect of the presence of uncertainty on the desired objective, which in turn yields an interpretation for the optimizing control as one that optimally attenuates the disturbance, viewed as the collection of unknown parameters and unknown signals entering the system dynamics. In addition to this disturbance attenuation property, the controllers obtained also feature adaptation in the sense that they help with identification of the unknown parameters, even though this has not been set as the primary goal of the design. In spite of this adaptation/identification role, the controllers obtained are not of certainty-equivalent type, which means that the identification and the control phases of the design are not decoupled.

  11. Plasmodium yoelii: induction of attenuated mutants by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Waki, S.; Yonome, I.; Suzuki, M.

    1986-12-01

    When erythrocytic forms of Plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to X rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 Krad). A suspension of 5 X 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. Eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. The infections of 8 mice of the 11 were self-resolving, and the attenuated feature of the parasites maintained following a limited number of blood passages. The parasites were slowly growing even in nude mice and cause self-resolving infections in intact mice. BALB/c mice immunized with the attenuated parasites were protected against subsequent challenge infections with the original virulent erythrocytic and sporogonic forms. These findings indicate that attenuated mutants of malaria parasites can be readily induced by this method.

  12. Attenuation Tomography of Sierra Negra Volcano of the Galapagos Archipelago

    Science.gov (United States)

    Rodd, R.; Lees, J. M.

    2014-12-01

    Following relocation of events with the double-difference location algorithm (HypoDD), we apply tomographic methods to extract 3D attenuation models illuminating the plumbing system of the Sierra Negra Caldera of the Galapagos Archipelago. The dataset consists of 1737 events recorded from July 2009 to June 2011 on the 17-station SIGNET broadband seismic array. We use t* spectral decay methods for both P- and S- phases with the clustered locations to highlight locations where significant variations in Q suggest the presence of magma melt. While the presence of a magma sill, at least 2 km depth, is indicated by InSAR and GPS studies, the delineated magma body has not been explored in detail. The lower bound of the proposed magma accumulation is still under question and thus forms the primary target of this research. Melt replenishment and degassing of the magma sill is believed to cause inflation and/or deflation of the caldera floor. Imaging the extent of the magma sill will provide insight into the feeder system and deformation process of the Sierra Negra caldera. Detailed relocation, Qp and Qs inversion, as well as estimates of the scattering attenuation using coda-normalization technique will be presented. The close relationship between seismic attenuation and the thermal state of the magmatic system suggests we can distinguish melt and/or fluid regions within the Sierra Negra plumbing system.

  13. Creating a collimated ultrasound beam in highly attenuating fluids.

    Science.gov (United States)

    Raeymaekers, Bart; Pantea, Cristian; Sinha, Dipen N

    2012-04-01

    We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate "frequency mixing tube" that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud.

  14. Frequency dependent Lg attenuation in south-central Alaska

    Science.gov (United States)

    McNamara, D.E.

    2000-01-01

    The characteristics of seismic energy attenuation are determined using high frequency Lg waves from 27 crustal earthquakes, in south-central Alaska. Lg time-domain amplitudes are measured in five pass-bands and inverted to determine a frequency-dependent quality factor, Q(f), model for south-central Alaska. The inversion in this study yields the frequency-dependent quality factor, in the form of a power law: Q(f) = Q0fη = 220(±30) f0.66(±0.09) (0.75≤f≤12Hz). The results from this study are remarkably consistent with frequency dependent quality factor estimates, using local S-wave coda, in south-central Alaska. The consistency between S-coda Q(f) and Lg Q(f) enables constraints to be placed on the mechanism of crustal attenuation in south-central Alaska. For the range of frequencies considered in this study both scattering and intrinsic attenuation mechanisms likely play an equal role.

  15. Neuropeptide FF receptors as novel targets for limbic seizure attenuation.

    Science.gov (United States)

    Portelli, Jeanelle; Meurs, Alfred; Bihel, Frederic; Hammoud, Hassan; Schmitt, Martine; De Kock, Joery; Utard, Valerie; Humbert, Jean-Paul; Bertin, Isabelle; Buffel, Ine; Coppens, Jessica; Tourwe, Dirk; Maes, Veronique; De Prins, An; Vanhaecke, Tamara; Massie, Ann; Balasubramaniam, Ambikaipakan; Boon, Paul; Bourguignon, Jean-Jacques; Simonin, Frederic; Smolders, Ilse

    2015-08-01

    Neuropeptide Y (NPY) is a well established anticonvulsant and first-in-class antiepileptic neuropeptide. In this study, the controversial role of NPY1 receptors in epilepsy was reassessed by testing two highly selective NPY1 receptor ligands and a mixed NPY1/NPFF receptor antagonist BIBP3226 in a rat model for limbic seizures. While BIBP3226 significantly attenuated the pilocarpine-induced seizures, neither of the highly selective NPY1 receptor ligands altered the seizure severity. Administration of the NPFF1/NPFF2 receptor antagonist RF9 also significantly attenuated limbic seizure activity. To further prove the involvement of NPFF receptors in these seizure-modulating effects, low and high affinity antagonists for the NPFF receptors were tested. We observed that the low affinity ligand failed to exhibit anticonvulsant properties while the two high affinity ligands significantly attenuated the seizures. Continuous NPFF1 receptor agonist administration also inhibited limbic seizures whereas bolus administration of the NPFF1 receptor agonist was without effect. This suggests that continuous agonist perfusion could result in NPFF1 receptor desensitization and mimic NPFF1 receptor antagonist administration. Our data unveil for the first time the involvement of the NPFF system in the management of limbic seizures.

  16. Genetically attenuated Trypanosoma cruzi parasites as a potential vaccination tool.

    Science.gov (United States)

    Pérez Brandan, Cecilia; Basombrío, Miguel Ángel

    2012-01-01

    Chagas disease is the clinical manifestation of the infection produced by the parasite Trypanosoma cruzi. Currently there is no vaccine to prevent this disease and the protection attained with vaccines containing non-replicating parasites is limited. Genetically attenuated trypanosomatid parasites can be obtained by deletion of selected genes. Gene deletion takes advantage of the fact that this parasite can undergo homologous recombination between endogenous and foreign DNA sequences artificially introduced in the cells. This approach facilitated the discovery of several unknown gene functions, as well as allowing us to speculate about the potential for genetically attenuated live organisms as experimental immunogens. Vaccination with live attenuated parasites has been used effectively in mice to reduce parasitemia and histological damage, and in dogs, to prevent vector-delivered infection in the field. However, the use of live parasites as immunogens is controversial due to the risk of reversion to a virulent phenotype. Herein, we present our results from experiments on genetic manipulation of two T. cruzi strains to produce parasites with impaired replication and infectivity, and using the mutation of the dhfr-ts gene as a safety device against reversion to virulence.

  17. Contaminant attenuation by shallow aquifer systems under steady flow

    Science.gov (United States)

    Soltani, S. S.; Cvetkovic, V.

    2017-10-01

    We present a framework for analyzing advection-dominated solute transport and transformation in aquifer systems of boreal catchments that are typically shallow and rest on crystalline bedrock. A methodology is presented for estimating tracer discharge based on particle trajectories from recharge to discharge locations and computing their first passage times assuming that the flow pattern is approximately steady-state. Transformation processes can be included by solving one-dimensional reactive transport with randomized water travel time as the independent variable; the distribution of the travel times incorporates morphological dispersion (due to catchment geometry/topography) as well as macro-dispersion (due to heterogeneity of underlying hydraulic properties). The implementation of the framework is illustrated for the well characterized coastal catchment of Forsmark (Sweden). We find that macro-dispersion has a notable effect on attenuation even though the morphological dispersion is significantly larger. Preferential flow on the catchment scale is found to be considerable with only 5% of the Eulerian velocities contributing to transport over the simulation period of 375 years. Natural attenuation is illustrated as a simple (linear decay) transformation process. Simulated natural attenuation can be estimated analytically reasonably well by using basic hydrological and structural information, the latter being the pathway length distribution and average aquifer depth to the bedrock.

  18. Multicomponent seismic noise attenuation with multivariate order statistic filters

    Science.gov (United States)

    Wang, Chao; Wang, Yun; Wang, Xiaokai; Xun, Chao

    2016-10-01

    The vector relationship between multicomponent seismic data is highly important for multicomponent processing and interpretation, but this vector relationship could be damaged when each component is processed individually. To overcome the drawback of standard component-by-component filtering, multivariate order statistic filters are introduced and extended to attenuate the noise of multicomponent seismic data by treating such dataset as a vector wavefield rather than a set of scalar fields. According to the characteristics of seismic signals, we implement this type of multivariate filtering along local events. First, the optimal local events are recognized according to the similarity between the vector signals which are windowed from neighbouring seismic traces with a sliding time window along each trial trajectory. An efficient strategy is used to reduce the computational cost of similarity measurement for vector signals. Next, one vector sample each from the neighbouring traces are extracted along the optimal local event as the input data for a multivariate filter. Different multivariate filters are optimal for different noise. The multichannel modified trimmed mean (MTM) filter, as one of the multivariate order statistic filters, is applied to synthetic and field multicomponent seismic data to test its performance for attenuating white Gaussian noise. The results indicate that the multichannel MTM filter can attenuate noise while preserving the relative amplitude information of multicomponent seismic data more effectively than a single-channel filter.

  19. Clinical evaluation strategies for a live attenuated tetravalent dengue vaccine.

    Science.gov (United States)

    Precioso, Alexander Roberto; Palacios, Ricardo; Thomé, Beatriz; Mondini, Gabriella; Braga, Patrícia; Kalil, Jorge

    2015-12-10

    Butantan Institute is a public Brazilian biomedical research-manufacturer center affiliated to the São Paulo State Secretary of Health. Currently, Butantan is one of the main public producers of vaccines, antivenoms, and antitoxins in Latin America. The partnership between Butantan and the National Institutes of Health (NIH) of the United Sates has been one of the longest and most successful partnerships in the development and manufacturing of new vaccines. Recently, Butantan Institute has developed and manufactured a lyophilized tetravalent live attenuated dengue vaccine with the four dengue viruses attenuated and licensed from the Laboratory of Infectious Diseases at The National Institutes of Allergy and Infectious Diseases (LID/NIAID/NIH). The objective of this paper is to describe the clinical evaluation strategies of a live attenuated tetravalent dengue vaccine (Butantan-DV) developed and manufactured by Butantan Institute. These clinical strategies will be used to evaluate the Butantan-DV Phase III trial to support the Butantan-DV licensure for protection against any symptomatic dengue caused by any serotype in people aged 2 to 59 years.

  20. A robust polynomial principal component analysis for seismic noise attenuation

    Science.gov (United States)

    Wang, Yuchen; Lu, Wenkai; Wang, Benfeng; Liu, Lei

    2016-12-01

    Random and coherent noise attenuation is a significant aspect of seismic data processing, especially for pre-stack seismic data flattened by normal moveout correction or migration. Signal extraction is widely used for pre-stack seismic noise attenuation. Principle component analysis (PCA), one of the multi-channel filters, is a common tool to extract seismic signals, which can be realized by singular value decomposition (SVD). However, when applying the traditional PCA filter to seismic signal extraction, the result is unsatisfactory with some artifacts when the seismic data is contaminated by random and coherent noise. In order to directly extract the desired signal and fix those artifacts at the same time, we take into consideration the amplitude variation with offset (AVO) property and thus propose a robust polynomial PCA algorithm. In this algorithm, a polynomial constraint is used to optimize the coefficient matrix. In order to simplify this complicated problem, a series of sub-optimal problems are designed and solved iteratively. After that, the random and coherent noise can be effectively attenuated simultaneously. Applications on synthetic and real data sets note that our proposed algorithm can better suppress random and coherent noise and have a better performance on protecting the desired signals, compared with the local polynomial fitting, conventional PCA and a L1-norm based PCA method.

  1. A study of the acoustical radiation force considering attenuation

    Science.gov (United States)

    Wu, RongRong; Liu, XiaoZhou; Gong, XiuFen

    2013-07-01

    Acoustical tweezer is a primary application of the radiation force of a sound field. When an ultrasound focused beam passes through a micro-particle, like a cell or living biological specimens, the particle will be manipulated accurately without physical contact and invasion, due to the three-dimensional acoustical trapping force. Based on the Ray acoustics approach in the Mie regime, this work discusses the effects on the particle caused by Gaussian focused ultrasound, studies the acoustical trapping force of spherical Mie particles by ultrasound in any position, and analyzes the numerical calculation on the two-dimensional acoustical radiation force. This article also analyzes the conditions for the acoustical trapping phenomenon, and discusses the impact of the initial position and size of the particle on the magnitude of the acoustical radiation force. Furthermore, this paper considers the ultrasonic attenuation in a particle in the case of two-dimension, studies the attenuation's effects on the acoustical trapping force, and amends the calculation to the ordinary case with attenuation.

  2. Resveratrol Attenuates Copper-Induced Senescence by Improving Cellular Proteostasis

    Directory of Open Access Journals (Sweden)

    Liliana Matos

    2017-01-01

    Full Text Available Copper sulfate-induced premature senescence (CuSO4-SIPS consistently mimetized molecular mechanisms of replicative senescence, particularly at the endoplasmic reticulum proteostasis level. In fact, disruption of protein homeostasis has been associated to age-related cell/tissue dysfunction and human disorders susceptibility. Resveratrol is a polyphenolic compound with proved antiaging properties under particular conditions. In this setting, we aimed to evaluate resveratrol ability to attenuate cellular senescence induction and to unravel related molecular mechanisms. Using CuSO4-SIPS WI-38 fibroblasts, resveratrol is shown to attenuate typical senescence alterations on cell morphology, senescence-associated beta-galactosidase activity, and cell proliferation. The mechanisms implicated in this antisenescence effect seem to be independent of senescence-associated genes and proteins regulation but are reliant on cellular proteostasis improvement. In fact, resveratrol supplementation restores copper-induced increased protein content, attenuates BiP level, and reduces carbonylated and polyubiquitinated proteins by autophagy induction. Our data provide compelling evidence for the beneficial effects of resveratrol by mitigating CuSO4-SIPS stressful consequences by the modulation of protein quality control systems. These findings highlight the importance of a balanced cellular proteostasis and add further knowledge on molecular mechanisms mediating resveratrol antisenescence effects. Moreover, they contribute to identifying specific molecular targets whose modulation will prevent age-associated cell dysfunction and improve human healthspan.

  3. An adaptive noise attenuation method for edge and amplitude preservation

    Institute of Scientific and Technical Information of China (English)

    Cai Han-Peng; He Zhen-Hua; Li Ya-Lin; He Guang-Ming; Zou Wen; Zhang Dong-Jun; Liu Pu

    2014-01-01

    Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and the subsequent seismic data interpretation, reservoir description, hydrocarbon detection, etc. Hence, we propose an adaptive noise attenuation method for edge and amplitude preservation, wherein the wavelet packet transform is used to decompose the full-band seismic signal into multiband data and then process these data using nonlinear anisotropic dip-oriented edge-preservingfi ltering. In the fi ltering, the calculated diffusion tensor from the structure tensor can be exploited to establish the direction of smoothing. In addition, the fault confidence measure and discontinuity operator can be used to preserve the structural and stratigraphic discontinuities and edges, and the decorrelation criteria can be used to establish the number of iterations. These parameters can minimize the intervention and subjectivity of the interpreter, and simplify the application of the proposed method. We applied the proposed method to synthetic and real 3D marine seismic data. We found that the proposed method could be used to attenuate noise in seismic data while preserving the effective discontinuity information and amplitude characteristics in seismic refl ection waves, providing high-quality data for interpretation and analysis such as high-resolution processing, attribute analysis, and inversion.

  4. Inflammation During Gestation Induced Spatial Memory and Learning Deficits: Attenuated by Physical Exercise in Juvenile Rats

    Science.gov (United States)

    Thangarajan, Rajesh; Rai, Kiranmai. S.; Gopalakrishnan, Sivakumar; Perumal, Vivek

    2015-01-01

    Background Gestational infections induced inflammation (GIII) is a cause of various postnatal neurological deficits in developing countries. Such intra uterine insults could result in persistent learning-memory disabilities. There are no studies elucidating the efficacy of adolescence exercise on spatial learning- memory abilities of young adult rats pre-exposed to inflammatory insult during fetal life. Aims and Objectives The present study addresses the efficacy of physical (running) exercise during adolescent period in attenuating spatial memory deficits induced by exposure to GIII in rats. Materials and Methods Pregnant Wistar dams were randomly divided into control and lipopolysaccharide (LPS) groups, injected intra peritoneally (i.p) with saline (0.5ml) or lipopolysaccharide (LPS) (0.5mg/kg) on alternate days from gestation day 14 (GD 14) till delivery. After parturition, pups were divided into 3 groups (n=6/group) a) Sham control and LPS group divided into 2 subgroups- b) LPS and c) LPS exercise group. Running exercise was given only to LPS exercise group during postnatal days (PNDs) 30 to 60 (15min/day). Spatial learning and memory performance was assessed by Morris water maze test (MWM), on postnatal day 61 to 67 in all groups. Results Young rats pre-exposed to GIII and subjected to running exercise through juvenile period displayed significant decrease in latency to reach escape platform and spent significant duration in target quadrant in MWM test, compared to age matched LPS group. Results of the current study demonstrated that exercise through juvenile/adolescent period effectively mitigates gestational inflammation-induced cognitive deficits in young adult rats. Conclusion Inflammation during gestation impairs offspring’s spatial memory and learning abilities. Whereas, early postnatal physical exercise attenuates, to higher extent, cognitive impairment resulted from exposure to LPS induced inflammation during intrauterine growth period. PMID:26266117

  5. Valproic acid attenuates the multiple-organ dysfunction in a rat model of septic shock

    Institute of Scientific and Technical Information of China (English)

    SHANG You; JIANG Yuan-xu; Ding Ze-jun; Shen Ai-ling; XU San-peng; YUAN Shi-ying; YAO Shang-long

    2010-01-01

    Background Valproic acid (VPA) improves early survival and organ function in a highly lethal poly-trauma and hemorrhagic shock model or other severe insults. We assessed whether VPA could improve organ function in a rat model of septic shock and illustrated the possible mechanisms.Methods Forty Sprague-Dawley rats were randomly assigned to four groups (n=10): control group, VPA group, LPS group, and LPS+VPA group. Lipopolysaccharide (LPS) (10 mg/kg) was injected intravenously to replicate the experimental model of septic shock. Rats were treated with VPA (300 mg/kg, i.v.) or saline. Six hours after LPS injection,blood was sampled for gas analysis, measurement of serum alanine aminotransferase, aspartate aminotransferase,urine nitrogen, creatinine and tumor necrosis factor-alpha. Lung, liver and kidney were collected for histopathological assessment. In addition, myeloperoxidase activity and tumor necrosis factor-α in pulmonary tissue were measured.Acetylation of histone H3 in lung was also evaluated by Western blotting.Results LPS resulted in a significant decrease in PaO2, which was increased by VPA administration followed LPS injection. In addition, LPS also induced an increase in the serum levels of alanine aminotransferase, aspartate aminotransferase, urine nitrogen, creatinine, and tumor necrosis factor-alpha. However, these increases were attenuated in the LPS+VPA group. The lungs, liver and kidneys from the LPS group were significantly damaged compared with the control group. However, the damage was attenuated in the LPS+VPA group. Myeloperoxidase activity and tumor necrosis factor-alpha levels in pulmonary tissue increased significantly in the LPS group compared with the control group. These increases were significantly inhibited in the LPS+VPA group. Acetylation of histone H3 in lung tissue in the LPS group was inhibited compared with the control. However, the level of acetylation of histone H3 in the LPS+VPA group was markedly elevated in contrast to the

  6. Role of translation in the UTP-modulated attenuation at the pyrBI operon of Escherichia coli

    DEFF Research Database (Denmark)

    Clemmesen, Kåre; Bonekamp, Fons; Karlström, Olle

    1985-01-01

    A 273 bp DNA fragment containing the attenuator of the pyrBI operon was inserted into a synthetic cloning site early in the lacZ gene on a plasmid. By this operation the first few codons of lacZ were joined through a linker to the last 39 codons of the open reading frame for the putative pyr......B leader peptide. In addition a gene fusion encoding a hybrid protein with -galactosidase activity was formed between the pyrB start and the rest of lacZ. This gene fusion is expressed from the lac promoter and the transcript is subject to facultative termination at the pyrBI attenuator. Different variants...... of the lacZ start were used that either contained a stop codon or directed the translation toward the attenuator in any of the alternative reading frames. The following results were obtained. No significant read-through of transcription over the pyrB attenuator was seen when the leader translation ended 49...

  7. Polymerase Mechanism-Based Method of Viral Attenuation

    Science.gov (United States)

    Lee, Cheri A.; August, Avery; Arnold, Jamie J.; Cameron, Craig E.

    2016-01-01

    Vaccines remain the most effective way of preventing infection and spread of infectious diseases. These prophylactics have been used for centuries but still to this day only three main design strategies exist: (1) live attenuated virus (LAV) vaccines, (2) killed or inactivated virus vaccines, (3) and subunit vaccines of the three, the most efficacious vaccines remain LAVs. LAVs replicate in relevant tissues, elicit strong cellular and humoral responses, and often confer lifelong immunity. While this vaccine strategy has produced the majority of successful vaccines in use today, there are also important safety concerns to consider with this approach. In the past, the development of LAVs has been empirical. Blind passage of viruses in various cell types results in the accumulation of multiple attenuating mutations leaving the molecular mechanisms of attenuation unknown. Also, due to the high error rate of RNA viruses and selective pressures of the host environment, these LAVs, derived from such viruses, can potentially revert back to wild-type virulence. This not only puts the vaccinee at risk, but if shed can put those that are unvaccinated at risk as well. While these vaccines have been successful there still remains a need for a rational design strategy by which to create additional LAVs. One approach for rational vaccine design involves increasing the fidelity of the viral RdRp. Increased fidelity decreases the viral mutational frequency thereby reducing the genetic variation the virus needs in order to evade the host imposed bottlenecks to infection. While polymerase mutants exist which decrease viral mutation frequency the mutations are not in conserved regions of the polymerase, which doesn’t lend itself toward using a common mutant approach toward developing a universal vaccine strategy for all RNA viruses. We have identified a conserved lysine residue in the active site of the PV RdRp that acts as a general acid during nucleotide incorporation. Mutation

  8. Comparison of Reg. Guide 1.99 fluence attenuation methods

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E.N. [TransWare Enterprises Inc., 1565 Mediterranean Dr., Sycamore, IL 60178 (United States)

    2011-07-01

    U.S. Regulatory Guide 1.99 Revision 2 (U.S. Nuclear Regulatory Commission, 1988, 'Radiation Embrittlement of Reactor Vessel Materials,' Regulatory Guide 1.99, Revision 2, Washington, D.C.) provides for the use of two substantially different methods for determining through-wall fluence in nuclear reactor pressure vessels. One method is a generic attenuation curve based on a simplistic exponential decay equation. Partly due to the simplicity of its application, the generic attenuation method is predominantly used for licensing calculations. However, it has a limitation in that at increasing distances away from the core belt-line, it becomes increasingly less accurate because it cannot account for neutron streaming effects in the cavity region surrounding the pressure vessel. The other attenuation method is based on a displacement per atom (dpa) calculation specific to the reactor vessel structure. The dpa method provides a more accurate representation of fluence attenuation through the reactor pressure vessel (RPV) wall at all elevations of the pressure vessel because it does account for neutron streaming in the cavity region. A requirement for using the dpa method, however, is an accurate flux solution through the RPV wall. This requirement has limited the use of traditional transport methods, such as discrete ordinates, that are limited by their treatment of cavity regions (i.e., air) outside the pressure vessel wall. TransWare Enterprises, under the sponsorship of EPRI and BWRVIR has developed an advanced three-dimensional transport methodology capable of producing fully converged flux solutions throughout the entire reactor system, including in the cavity region and primary shield structures. This methodology provides an accurate and reliable determination of through-wall fluence in boiling water reactor (BWR) and pressurized water reactor (PWR) pressure vessels, thus allowing the dpa method to be implemented with high reliability. Using this advanced 3

  9. Forward- vs. Inverse Problems in Modeling Seismic Attenuation

    Science.gov (United States)

    Morozov, I. B.

    2015-12-01

    Seismic attenuation is an important property of wave propagation used in numerous applications. However, the attenuation is also a complex phenomenon, and it is important to differentiate between its two typical uses: 1) in forward problems, to model the amplitudes and spectral contents of waves required for hazard assessment and geotechnical engineering, and 2) in inverse problems, to determine the physical properties of the subsurface. In the forward-problem sense, the attenuation is successfully characterized in terms of empirical parameters of geometric spreading, radiation patterns, scattering amplitudes, t-star, alpha, kappa, or Q. Arguably, the predicted energy losses can be correct even if the underlying attenuation model is phenomenological and not sufficiently based on physics. An example of such phenomenological model is the viscoelasticity based on the correspondence principle and the Q-factor assigned to the material. By contrast, when used to invert for in situ material properties, models addressing the specific physics are required. In many studies (including in this session), a Q-factor is interpreted as a property of a point within the subsurface; however this property is only phenomenological and may be physically insufficient or inconsistent. For example, the bulk or shear Q at the same point can be different when evaluated from different wave modes. The cases of frequency-dependent Q are particularly prone of ambiguities such as trade-off with the assumed background geometric spreading. To rigorously characterize the in situ material properties responsible for seismic-wave attenuation, it is insufficient to only focus on the seismic energy loss. Mechanical models of the material need to be considered. Such models can be constructed by using Lagrangian mechanics. These models should likely contain no Q but will be based on parameters of microstructure such as heterogeneity, fractures, or fluids. I illustrate several such models based on viscosity

  10. MR constrained simultaneous reconstruction of activity and attenuation maps in brain TOF-PET/MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mehranian, Abolfazl; Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland)

    2014-07-29

    The maximum likelihood estimation of attenuation and activity (MLAA) algorithm has been proposed to jointly estimate activity and attenuation from emission data only. Salomon et al employed the MLAA to estimate activity and attenuation from time-of-flight PET data with spatial MR prior information on attenuation. Recently, we proposed a novel algorithm to impose both spatial and statistical constraints on attenuation estimation within the MLAA algorithm using Dixon MR images and a constrained Gaussian mixture model (GMM). In this study, we compare the proposed algorithm with MLAA and MLAA-Salomon in brain TOF-PET/MR imaging.

  11. Empirical Relations for Optical Attenuation Prediction from Liquid Water Content of Fog

    Directory of Open Access Journals (Sweden)

    M. S. Khan

    2012-09-01

    Full Text Available Simultaneous measurements of the liquid water content (LWC and optical attenuation have been analyzed to predict optical attenuation caused by fog particles. Attenuation has been measured at two different wavelengths, 830 nm and 1550 nm, across co-located links. Five months measured data have been processed to assess power-law empirical models, which estimate optical attenuation from the LWC. The proposed models are compared with other published models and are demonstrated to perform sufficiently well to predict optical attenuation if the LWC values are available.

  12. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  13. A study on photon attenuation coefficients of different wood materials with different densities

    Science.gov (United States)

    Saritha, B.; Nageswara Rao, A. S.

    2015-12-01

    A study on the variation of linear attenuation coefficients with the densities of the wood samples is under taken. The soft wood and hard wood samples were collected from the forest area of Pakal in Warangal district. The linear and mass attenuation coefficients are measured using gamma ray spectrometry based on NaI (Tl) scintillation detector with energies of 662 KeV and 59.5 KeV respectively. The mass attenuation coefficient values measured from experiment and are compared with theoretical methods using XCOM program. The plots of density versus linear attenuation coefficient for different wood materials correspond to higher order polynomial are presented. It is observed that variation of linear attenuation coefficient depends on densities of materials. The Chloroxylon swietenia with more density has more linear attenuation coefficient at 59.5 KeV and 662 KeV. The variation in attenuation coefficient attributed to chemical composition of wood used in the experiment.

  14. P-wave attenuation anisotropy in TI media and its application in fracture parameters inversion

    Science.gov (United States)

    He, Yi-Yuan; Hu, Tian-Yue; He, Chuan; Tan, Yu-Yang

    2016-12-01

    The existence of aligned fractures in fluid-saturated rocks leads to obvious attenuation anisotropy and velocity anisotropy. Attenuation anisotropy analysis can be applied to estimate fracture density and scale, which provide important information for reservoir identification. This paper derives P-wave attenuation anisotropy in the ATI media where the symmetry axis is in the arbitrary direction theoretically and modifies the spectral ratio method to measure attenuation anisotropy in the ATI media, thus avoiding a large measurement error when applied to wide azimuth or full azimuth data. Fracture dip and azimuth can be estimated through attenuation anisotropy analysis. For small-scale fractures, fracture scale and fracture density can be determined with enhanced convergence if velocity and attenuation information are both used. We also apply the modified spectralratio method to microseismic field data from an oilfield in East China and extract the fracture dip through attenuation anisotropy analysis. The result agrees with the microseismic monitoring.

  15. Gene Transcription Profile in Mice Vaccinated with Ultraviolet-attenuated Cercariae of Schistosoma japonicum Reveals Molecules Contributing to Elevated IFN-γLevels

    Institute of Scientific and Technical Information of China (English)

    Xiang ZHU; Feng LIU; Chuan SU; Guan-Ling WU; Zhao-Song ZHANG; Min-Jun JI; Hai-Wei WU; Yong WANG; Xiao-Ping CAI; Lei ZHANG; Shu-Ying HU; Lin-Lin FU

    2005-01-01

    Vaccination with ultraviolet-attenuated cercariae of Schistosoma japonicum induced protective immunity against challenge infection in experimental animal models. Our preliminary study on the transcription levels of IFN-γ and IL-4 in splenic CD4+ T cells revealed that attenuated cercariae elicited predominantly a Thl response in mice at the early stage, whereas normal cercariae stimulated primarily Th2dependent responses. Further analysis on the gene profile of the skin-draining lymph nodes demonstrated that the levels of IFN-γ were significantly higher in vaccinated mice than those in infected mice at day 4, 7 and 14 post-vaccination or post-infection. However, for IL-12 and IL-4, the potent inducers of Th l and Th2 responses, respectively, as well as IL-10, there were no differences over the course of the experiment between the infected and vaccinated mice. To explore the underlying factors that may potentially contribute to elevated IFN-γ in vaccinated mice, the mRNA profiles of the skin-draining lymph nodes at day 4 postexposure were compared using oligonucleotide microarrays. Within the 847 probe sets with increased signal values, we focused on chemokines, cytokines and relevant receptors, which were validated by semi-quantitative RT-PCR. A comprehensive understanding of the immune mechanisms of attenuated cercariae-induced protection may contribute to developing efficient vaccination strategies against S. japonicum, especially during the early stage of infection.

  16. Derivation of attenuation map for attenuation correction of PET data in the presence of nanoparticulate contrast agents using spectral CT imaging

    NARCIS (Netherlands)

    Ghadiri, Hossein; Shiran, Mohammad Bagher; Soltanian-Zadeh, Hamid; Rahmim, Arman; Zaidi, Habib; Ay, Mohammad Reza

    2014-01-01

    Uptake value in quantitative PET imaging is biased due to the presence of CT contrast agents when using CT-based attenuation correction. Our aim was to examine spectral CT imaging to suppress inaccuracy of 511 keV attenuation map in the presence of multiple nanoparticulate contrast agents. Using a s

  17. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design.

    Science.gov (United States)

    Yamshchikov, Vladimir; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-01

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E138K and K279M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use.

  18. Optimizing Early Retirement Decisions.

    Science.gov (United States)

    2007-11-02

    the military. The U.S. Army’s early retirement program is a temporary one designed to allow some soldiers to leave the service prior to 20 years of...whether it makes financial sense for an officer to select early retirement . A spreadsheet formulation is developed and used to indicate if and when...an officer should select early retirement . The program investigates the decision that various civilian salary levels and various assumed discount rates.

  19. Estrogen attenuates the exercise pressor reflex in female cats.

    Science.gov (United States)

    Schmitt, Petra M; Kaufman, M P

    2003-10-01

    In humans, the pressor and muscle sympathetic nerve responses to static exercise are less in women than in men. The difference has been attributed to the effect of estrogen on the exercise pressor reflex. Estrogen receptors are abundant in areas of the dorsal horn receiving input from group III and IV muscle afferents, which comprise the sensory limb of the exercise pressor reflex arc. These findings prompted us to investigate the effect of estrogen on the spinal pathway of the exercise pressor reflex arc. Previously, we found that the threshold concentration of 17beta-estradiol needed to attenuate the exercise pressor reflex in male decerebrate cats was 10 microg/ml (Schmitt PM and Kaufman MP. J Appl Physiol 94: 1431-1436, 2003). The threshold concentration for female cats, however, is not known. Consequently, we applied 17beta-estradiol to a well covering the L6-S1 spinal cord in decerebrate female cats. The exercise pressor reflex was evoked by electrical stimulation of the L7 or S1 ventral root, a maneuver that caused the hindlimb muscles to contract statically. We found that the pressor response to contraction averaged 38 +/- 7 mmHg before the application of 17beta-estradiol (0.01 microg/ml) to the spinal cord, whereas it averaged only 23 +/- 4 mmHg 30 min after application (P effect on the exercise pressor reflex (n = 5). We conclude that the concentration of 17beta-estradiol required to attenuate the exercise pressor reflex is 1,000 times more dilute in female cats than that needed to attenuate this reflex in male cats.

  20. Optical coherence tomography for blood glucose monitoring through signal attenuation

    Science.gov (United States)

    De Pretto, Lucas R.; Yoshimura, Tania M.; Ribeiro, Martha S.; de Freitas, Anderson Z.

    2016-03-01

    Development of non-invasive techniques for glucose monitoring is crucial to improve glucose control and treatment adherence in patients with diabetes. Hereafter, Optical Coherence Tomography (OCT) may offer a good alternative for portable glucometers, since it uses light to probe samples. Changes in the object of interest can alter the intensity of light returning from the sample and, through it, one can estimate the sample's attenuation coefficient (μt) of light. In this work, we aimed to explore the behavior of μt of mouse's blood under increasing glucose concentrations. Different samples were prepared in four glucose concentrations using a mixture of heparinized blood, phosphate buffer saline and glucose. Blood glucose concentrations were measured with a blood glucometer, for reference. We have also prepared other samples diluting the blood in isotonic saline solution to check the effect of a higher multiple-scattering component on the ability of the technique to differentiate glucose levels based on μt. The OCT system used was a commercial Spectral Radar OCT with 930 nm central wavelength and spectral bandwidth (FWHM) of 100 nm. The system proved to be sensitive for all blood glucose concentrations tested, with good correlations with the obtained attenuation coefficients. A linear tendency was observed, with an increase in attenuation with higher values of glucose. Statistical difference was observed between all groups (p<0.001). This work opens the possibility towards a non-invasive diagnostic modality using OCT for glycemic control, which eliminates the use of analytes and/or test strips, as in the case with commercially available glucometers.