Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood.

PubMed

Lima, Manoel C S; Barbosa, Maurício F; Diniz, Tiego A; Codogno, Jamile S; Freitas Júnior, Ismael F; Fernandes, Rômulo A

2014-01-01

It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b95%CI=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity.

Retained Subintimal Pellet in a Carotid Artery

PubMed Central

Manousi, Maria; Sarantitis, Ioannis; Diamantopoulos, Athanasios; Kakkos, Stavros K.; Lampropoulos, George; Tsolakis, Ioannis A.

2011-01-01

A shotgun pellet is depicted in the present image in a carotid artery under the intima, which remained intact without local complications for up to six months. There is lack of data regarding the natural history of such a carotid pellet, but the experience from the myocardium is that, in the absence of infection, completely embedded missiles are usually asymptomatic, tolerated well and may be left in place. PMID:21860728

Association between endothelial dysfunction, epicardial fat and subclinical atherosclerosis during menopause.

PubMed

Cabrera-Rego, Julio Oscar; Navarro-Despaigne, Daisy; Staroushik-Morel, Liudmila; Díaz-Reyes, Karel; Lima-Martínez, Marcos M; Iacobellis, Gianluca

Menopausal transition is critical for the development of early, subclinical vascular damage. Multiple factors, such as atherosclerosis, increased epicardial fat, and endothelial dysfunction can play a role. Hence, the objective of this study was the comparison of epicardial adipose tissue and carotid intima media thickness in order to establish the best predictor of carotid stiffness in middle-aged women with endothelial dysfunction. A total of 43 healthy women aged 40-59 years old with endothelial dysfunction previously demonstrated by flow mediated dilation were recruited to have anthropometric, biochemical, hormonal and ultrasound determinations of carotid intima media thickness and epicardial fat thickness. Carotid arterial stiffness parameters (local pulse wave velocity [4.7±0.7 vs 4.8±0.5 vs 5.6±0.5m/s, respectively, p<0.001], pressure strain elastic modulus [55.2±13.4 vs 59.2±11.8 vs 81.9±15.6kPa, respectively, p<0.001], arterial stiffness index β [4.4±1.4 vs 5.0±1.1 vs 6.4±1.3, respectively, p<0.001]) and epicardial fat thickness (2.98±1.4 vs 3.28±1.9 vs 4.70±1.0mm, respectively, p=0.007) showed a significant and proportional increase in the group of late post-menopausal women when compared to early post-menopausal and pre-menopausal groups, respectively. Among body fat markers, epicardial fat was the strongest predictor of local pulse wave velocity, independent of age. In menopausal women with endothelial dysfunction, menopausal transition is associated with increased carotid arterial stiffness and epicardial fat thickness, independent of age. Ultrasound measured epicardial fat was a better independent predictor of arterial stiffness than carotid intima media thickness in these women. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

Accuracy Evaluation in the Measurement of a Small Change in the Thickness of Arterial Walls and the Measurement of Elasticity of the Human Carotid Artery

NASA Astrophysics Data System (ADS)

Hasegawa, Hideyuki; Kanai, Hiroshi; Hoshimiya, Nozomu; Chubachi, Noriyoshi; Koiwa, Yoshiro

1998-05-01

For the diagnosis of the early stages of atherosclerosis, it isimportant to evaluate the local acoustic characteristics of thearterial wall. For this purpose, it is necessary to increase thespatial resolution in the axial direction to several millimeters,which corresponds to the size of the macular lesion on the surface ofthe wall. We have proposed a method for measuring small velocitysignals on the intima and adventitia of the arterial wall from theskin surface using pulsive ultrasonic waves. The small change inthickness of the arterial wall is obtained by integrating thedifference between the two velocity signals on the intima andadventitia. The elastic property of the arterial wall is noninvasivelyevaluated from the change in thickness and the arterial innerpressure. In this paper, we evaluate the accuracy of the proposedmethod for measuring the small displacement. Moreover, we applied thismethod to evaluate the elastic property of the arterial wall of 50patients and 8 healthy subjects.

Carotid intima media thickness and plaques can predict the occurrence of ischemic cerebrovascular events.

PubMed

Prati, Patrizio; Tosetto, Alberto; Vanuzzo, Diego; Bader, Giovanni; Casaroli, Marco; Canciani, Luigi; Castellani, Sergio; Touboul, Pierre-Jean

2008-09-01

The clinical usefulness of noninvasive measurement of carotid intima media thickness and plaque visualization in the general population is still uncertain. We evaluated the age-specific incidence rates of cerebrovascular events in a cohort of 1348 subjects randomly taken from the census list of San Daniele Township and followed for a mean period of 12.7 years. The association among common carotid intima media thickness, measured at baseline, arterial risk factors, and incidence of ischemic cerebrovascular events was modeled using Poisson regression. The predictive ability of common carotid intima media thickness over arterial risk factors (summarized in the Framingham Stroke Risk Score) was evaluated by receiver operating characteristic curve analysis. During the follow-up, 115 subjects developed nonfatal ischemic stroke, transient ischemic attack, or vascular death, which were the predefined study end points. After adjustment for age and sex, hypertension, diabetes, common carotid intima media thickness above 1 mm, and carotid plaques were all independent risk factors for development of vascular events. Inclusion of carotid findings (presence of common carotid intima media thickness above 1 mm or carotid plaques) resulted in a predictive power higher than Framingham Stroke Risk Score alone only on for those subjects with a Framingham Stroke Risk Score over 20%. Although common carotid intima media thickness and presence of carotid plaques are known to be risk factors for the development of vascular events and to be independent from the conventional risk factors summarized in the Framingham Stroke Risk Score, their contribution to individual risk prediction is limited. Further studies will be required to address the role of carotid ultrasonography in the primary prevention of high-risk subjects.

Effects of oxcarbazepine treatment on serum lipids and carotid intima media thickness in children.

PubMed

Yiş, Uluç; Doğan, Mustafa

2012-03-01

The aim of this study is to evaluate the carotid intima media thickness and serum lipids in pediatric patients with epilepsy treated with oxcarbazepine. The study included 21 pediatric epileptic and 22 healthy children. Intima media thickness and fasting lipid profile were assessed. Although the median value of total cholesterol was in normal limits in the oxcarbazepine group, it was significantly higher when compared with the control group. We did not observe any differences regarding triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and carotid intima media thickness. We suggest that oxcarbazepine treatment in children has a minor effect on serum lipids and it does not seem to have an atherogenic effect. Copyright © 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Inflammation, homocysteine and carotid intima-media thickness.

PubMed

Baptista, Alexandre P; Cacdocar, Sanjiva; Palmeiro, Hugo; Faísca, Marília; Carrasqueira, Herménio; Morgado, Elsa; Sampaio, Sandra; Cabrita, Ana; Silva, Ana Paula; Bernardo, Idalécio; Gome, Veloso; Neves, Pedro L

2008-01-01

Cardiovascular disease is the main cause of morbidity and mortality in chronic renal patients. Carotid intima-media thickness (CIMT) is one of the most accurate markers of atherosclerosis risk. In this study, the authors set out to evaluate a population of chronic renal patients to determine which factors are associated with an increase in intima-media thickness. We included 56 patients (F=22, M=34), with a mean age of 68.6 years, and an estimated glomerular filtration rate of 15.8 ml/min (calculated by the MDRD equation). Various laboratory and inflammatory parameters (hsCRP, IL-6 and TNF-alpha) were evaluated. All subjects underwent measurement of internal carotid artery intima-media thickness by high-resolution real-time B-mode ultrasonography using a 10 MHz linear transducer. Intima-media thickness was used as a dependent variable in a simple linear regression model, with the various laboratory parameters as independent variables. Only parameters showing a significant correlation with CIMT were evaluated in a multiple regression model: age (p=0.001), hemoglobin (p=00.3), logCRP (p=0.042), logIL-6 (p=0.004) and homocysteine (p=0.002). In the multiple regression model we found that age (p=0.001) and homocysteine (p=0.027) were independently correlated with CIMT. LogIL-6 did not reach statistical significance (p=0.057), probably due to the small population size. The authors conclude that age and homocysteine correlate with carotid intima-media thickness, and thus can be considered as markers/risk factors in chronic renal patients.

Effect of rosuvastatin on the echolucency of the common carotid intima-media in low-risk individuals: the METEOR trial.

PubMed

Lind, Lars; Peters, Sanne A E; den Ruijter, Hester M; Palmer, Mike K; Grobbee, Diederick E; Crouse, John R; O'Leary, Daniel H; Evans, Gregory W; Raichlen, Joel S; Bots, Michiel L

2012-10-01

The echolucency of the carotid intima-media is related to increased cardiovascular risk factor levels, morbidity, and mortality. The aim of this study was to assess the effect of statins on the echolucency of the common carotid intima-media in a low-risk population. Data from the Measuring Effects on Intima-Media Thickness: An Evaluation of Rosuvastatin study were used. Ultrasound images from the far walls of the left and right common carotid arteries were used for evaluation of the echolucency of the carotid intima-media, measured by grayscale median (GSM). Low GSM values reflect echolucent structures, whereas high values reflect echogenic structures. The primary end point was the difference in the annual rate of change in GSM between rosuvastatin and placebo. Two-year change in GSM did not significantly differ between rosuvastatin and placebo in the total population, with a mean difference in the rate of change in GSM of 1.13 (95% confidence interval, -1.00 to 3.25). The effect of rosuvastatin differed across quintiles of baseline GSM values (P for interaction = .01). In the lowest quintile (n = 175) (i.e., in those with the most echolucent intima-media), the difference in the rate of change in GSM between rosuvastatin and placebo was 4.18 (95% confidence interval, -0.23 to 8.58). Increases in GSM were significantly related to decreasing low-density lipoprotein cholesterol levels in the lowest quintile (β = 0.76; 95% confidence interval, 0.26 to 1.25). Treatment with rosuvastatin did not affect the echolucency of the arterial wall in all low-risk individuals. However, a potential effect of rosuvastatin on the echolucency of the common carotid intima-media is most likely to be found in individuals with echolucent arterial walls at baseline. Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

Measurement of the ultrasonic properties of human coronary arteries in vitro with a 50-MHz acoustic microscope.

PubMed

Machado, J C; Foster, F S; Gotlieb, A I

2002-08-01

Ultrasonic attenuation coefficient, wave propagation speed and integrated backscatter coefficient (IBC) of human coronary arteries were measured in vitro over the -6 dB frequency bandwidth (36 to 67 MHz) of a focused ultrasound transducer (50 MHz, focal distance 5.7 mm, f/number 1.7). Corrections were made for diffraction effects. Normal and diseased coronary artery sub-samples (N = 38) were obtained from 10 individuals at autopsy. The measured mean +/- SD of the wave speed (average over the entire vessel wall thickness) was 1581.04 +/- 53.88 m/s. At 50 MHz, the average attenuation coefficient was 4.99 +/- 1.33 dB/mm with a frequency dependence term of 1.55 +/- 0.18 determined over the 36- to 67-MHz frequency range. The IBC values were: 17.42 +/- 13.02 (sr.m)-1 for thickened intima, 11.35 +/- 6.54 (sr.m)-1 for fibrotic intima, 39.93 +/- 50.95 (sr.m)-1 for plaque, 4.26 +/- 2.34 (sr.m)-1 for foam cells, 5.12 +/- 5.85 (sr.m)-1 for media and 21.26 +/- 31.77 (sr.m)-1 for adventitia layers. The IBC results indicate the possibility for ultrasound characterization of human coronary artery wall tissue layer, including the situations of diseased arteries with the presence of thickened intima, fibrotic intima and plaque. The mean IBC normalized with respect to the mean IBC of the media layer seems promising for use as a parameter to differentiate a plaque or a thickened intima from a fibrotic intima.

Modelling the layer-specific three-dimensional residual stresses in arteries, with an application to the human aorta

PubMed Central

Holzapfel, Gerhard A.; Ogden, Ray W.

2010-01-01

This paper provides the first analysis of the three-dimensional state of residual stress and stretch in an artery wall consisting of three layers (intima, media and adventitia), modelled as a circular cylindrical tube. The analysis is based on experimental results on human aortas with non-atherosclerotic intimal thickening documented in a recent paper by Holzapfel et al. ( Holzapfel et al. 2007 Ann. Biomed. Eng. 35, 530–545 (doi:10.1007/s10439-006-9252-z)). The intima is included in the analysis because it has significant thickness and load-bearing capacity, unlike in a young, healthy human aorta. The mathematical model takes account of bending and stretching in both the circumferential and axial directions in each layer of the wall. Previous analysis of residual stress was essentially based on a simple application of the opening-angle method, which cannot accommodate the three-dimensional residual stretch and stress states observed in experiments. The geometry and nonlinear kinematics of the intima, media and adventitia are derived and the associated stress components determined explicitly using the nonlinear theory of elasticity. The theoretical results are then combined with the mean numerical values of the geometrical parameters and material constants from the experiments to illustrate the three-dimensional distributions of the stretches and stresses throughout the wall. The results highlight the compressive nature of the circumferential stress in the intima, which may be associated with buckling of the intima and its delamination from the media, and show that the qualitative features of the stretch and stress distributions in the media and adventitia are unaffected by the presence or absence of the intima. The circumferential residual stress in the intima increases significantly as the associated residual deformation in the intima increases while the corresponding stress in the media (which is compressive at its inner boundary and tensile at its outer boundary) is only slightly affected. The theoretical framework developed herein enables the state of residual stress to be calculated directly, serves to improve insight into the mechanical response of an unloaded artery wall and can be extended to accommodate more general geometries, kinematics and states of residual stress as well as more general constitutive models. PMID:19828496

Carotid artery intima-media thickness measurement in children with normal and increased body mass index: a comparison of three techniques.

PubMed

El Jalbout, Ramy; Cloutier, Guy; Cardinal, Marie-Hélène Roy; Henderson, Mélanie; Lapierre, Chantale; Soulez, Gilles; Dubois, Josée

2018-05-09

Common carotid artery intima-media thickness is a marker of subclinical atherosclerosis. In children, increased intima-media thickness is associated with obesity and the risk of cardiovascular events in adulthood. To compare intima-media thickness measurements using B-mode ultrasound, radiofrequency (RF) echo tracking, and RF speckle probability distribution in children with normal and increased body mass index (BMI). We prospectively measured intima-media thickness in 120 children randomly selected from two groups of a longitudinal cohort: normal BMI and increased BMI, defined by BMI ≥85th percentile for age and gender. We followed Mannheim recommendations. We used M'Ath-Std for automated B-mode imaging, M-line processing of RF signal amplitude for RF echo tracking, and RF signal segmentation and averaging using probability distributions defining image speckle. Statistical analysis included Wilcoxon and Mann-Whitney tests, and Pearson correlation coefficient and intra-class correlation coefficient (ICC). Children were 10-13 years old (mean: 11.7 years); 61% were boys. The mean age was 11.4 years (range: 10.0-13.1 years) for the normal BMI group and 12.0 years (range: 10.1-13.5 years) for the increased BMI group. The normal BMI group included 58% boys and the increased BMI group 63% boys. RF echo tracking method was successful in 79 children as opposed to 114 for the B-mode method and all 120 for the probability distribution method. Techniques were weakly correlated: ICC=0.34 (95% confidence interval [CI]: 0.27-0.39). Intima-media thickness was significantly higher in the increased BMI than normal BMI group using the RF techniques and borderline for the B-mode technique. Mean differences between weight groups were: B-mode, 0.02 mm (95% CI: 0.00 to 0.04), P=0.05; RF echo tracking, 0.03 mm (95% CI: 0.01 to 0.05), P=0.01; and RF speckle probability distribution, 0.03 mm (95% CI: 0.01 to 0.05), P=0.002. Though techniques are not interchangeable, all showed increased intima-media thickness in children with increased BMI. RF echo tracking method had the lowest success rate at calculating intima-media thickness. For patient follow-up and cohort comparisons, the same technique should be used throughout.

[The relationship between oxidized form glutathione, coenzyme II and carotid artery atherosclerosis].

PubMed

Huang, Yan-sheng; Wang, Shu-ren; Zhi, Yan-fang; Xu, Bo-shi; Sun, Lin; Wu, Yu; Lu, Jian-min; Dai, Fu-min

2006-06-01

To explore the relationship between plasma redox status and atherosclerosis. IVUS was performed in common carotid in the neck of 167 patients with heart diseases. Patients were divided into three groups: plaque-forming group (A, n = 79), intima-thickening group (B, n = 52) and control group (C, n = 36). Plasma glutathione (reduced form GSH and oxidized form GSSG), nicotinamide adenine dinucleotide phosphate (reduced form NADPH and oxidized form NADP(+)), oxidized low density lipoprotein (ox-LDL) and malondialdehyde (MDA) were measured in all patients. The GSH/GSSG and NADPH/NADP(+) redox potential were calculated according to Nernst equation, and correlation analysis performed. GSH and GSH/GSSG gradually reduced and GSH/GSSG redox potential gradually increased in proportion to the thickening of artery intima (from Group C to Group A, P < 0.05). Similar but milder results were shown for NADPH and NADPH/NADP(+) redox status. The products of oxidative stress ox-LDL and MDA also increased significantly (P < 0.05) in proportion to the thickening of artery intima. GSH/GSSG redox potential is positively correlated to ox-LDL (P < 0.05). The redox status shifted to oxidizing direction in proportion to the intima thickness. The imbalance of plasma redox status deviating to oxidation might be implicated in oxidized injury of lipid, intima thickening and atherosclerosis progress.

Subclinical atherosclerosis in obese adolescents with normal left ventricular function.

PubMed

Abdel-Wahab, Amina M; Atwa, Hoda A; El-Eraky, Azza Z; El-Aziz, Mohamed A

2011-09-01

To assess the impact of obesity on carotid intima media thickness and left ventricular (LV) mass in obese adolescents. The study included 52 obese adolescents (mean age 14.16+/-2.64 years) and 52 healthy adolescents who served as a control group (mean age 12+/-2.3 years), who were attended the outpatient clinic at Suez Canal University Hospital, Ismailia, Egypt. The study population was submitted for medical history, clinical examination, laboratory investigations (fasting blood sugar and lipid profile), and echocardiographic examination of LV mass and dimensions. Assessment of carotid intima-media thickness was carried out by using carotid duplex. All children had normal LV function. Obese adolescents had a significant increase in total cholesterol, triglyceride, LDL-C, and low HDL-C compared to the control group. Also, there was a significant increase in blood pressure, carotid intima media thickness, LV mass, and LV mass index. There was a significant correlation between BMI and dyslipidemia, blood pressure, carotid intima/media thickness, LV mass, and posterior wall thickness. Carotid intima-media thickness had a significant correlation with increased LDL-C and low HDL-C, blood pressure, LV mass, and posterior wall thickness. Obesity in childhood and adolescents is associated with subclinical atherosclerosis. Although obese children had no LV dysfunction, yet there are LV structure changes.

Quantitative Measurement of Dissection Resistance in Intimal and Medial Layers of Human Coronary Arteries

PubMed Central

Wang, Ying; Johnson, John A.; Spinale, Francis G.; Sutton, Michael A.; Lessner, Susan M.

2014-01-01

The left anterior descending (LAD) coronary artery is the most frequently involved vessel in coronary artery dissection, a cause of acute coronary syndrome or sudden cardiac death. The biomechanical mechanisms underlying arterial dissection are not well understood. This study investigated the dissection properties of LAD specimens harvested from explanted hearts at the time of cardiac transplantation, from patients with primary dilated cardiomyopathy (n=12). Using a previously validated approach uniquely modified for these human LAD specimens, we quantified the local energy release rate, G, within different arterial layers during experimental dissection events (tissue tearing). Results show that the mean values of G during arterial dissection within the intima and within the media in human LADs are 20.7±16.5 J/m2 and 10.3±5.0 J/m2, respectively. The difference in dissection resistance between tearing events occurring within the intima and within the media is statistically significant. Our data fall in the same order of magnitude as most previous measurements of adhesive strength in other human arteries, with the differences in measured values of G within the layers most likely due to histologically observed differences in the structure and composition of arterial layers. PMID:24729631

Race or vitamin D: A determinant of intima media thickness in obese adolescents?

USDA-ARS?s Scientific Manuscript database

Carotid intima media thickness (IMT), a predictor of cardiovascular events, is reported to be higher in African-American (AA) vs. White (AW) individuals. We investigated whether racial differences in IMT in obese adolescents could be explained by differences in 25 hydroxy-vitamin D [25(OH)D]. A tota...

The Short-Term Effect of Ketogenic Diet on Carotid Intima-Media Thickness and Elastic Properties of the Carotid Artery and the Aorta in Epileptic Children.

PubMed

Doksöz, Önder; Güzel, Orkide; Yılmaz, Ünsal; İşgüder, Rana; Çeleğen, Kübra; Meşe, Timur; Uysal, Utku

2015-10-01

The aim of this prospective study is to investigate the effect of a 6-month-long ketogenic diet on carotid intima-media thickness, carotid artery, and aortic vascular functions. Thirty-eight drug-resistant epileptic patients who were being treated with ketogenic diet were enrolled. Fasting total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, total cholesterol, and glucose concentrations were measured and echocardiography was performed in all patients before the beginning of ketogenic diet and at the sixth month of treatment. The body weight, height, body mass index, serum levels of triglyceride, total cholesterol, and low-density lipoprotein increased significantly at month 6 when compared to baseline values (P < .05). Carotid intima-media thickness, elastic properties of the aorta, and carotid artery did not change at the sixth month of therapy compared to baseline values. A 6-month-long ketogenic diet has no effect on carotid intima-media thickness and elastic properties of the carotid artery and the aorta. © The Author(s) 2015.

Association between cardiovascular risk factors and carotid intima-media thickness in prepubertal Brazilian children.

PubMed

Gazolla, Fernanda Mussi; Neves Bordallo, Maria Alice; Madeira, Isabel Rey; de Miranda Carvalho, Cecilia Noronha; Vieira Monteiro, Alexandra Maria; Pinheiro Rodrigues, Nádia Cristina; Borges, Marcos Antonio; Collett-Solberg, Paulo Ferrez; Muniz, Bruna Moreira; de Oliveira, Cecilia Lacroix; Pinheiro, Suellen Martins; de Queiroz Ribeiro, Rebeca Mathias

2015-05-01

Early exposure to cardiovascular risk factors creates a chronic inflammatory state that could damage the endothelium followed by thickening of the carotid intima-media. To investigate the association of cardiovascular risk factors and thickening of the carotid intima. Media in prepubertal children. In this cross-sectional study, carotid intima-media thickness (cIMT) and cardiovascular risk factors were assessed in 129 prepubertal children aged from 5 to 10 year. Association was assessed by simple and multivariate logistic regression analyses. In simple logistic regression analyses, body mass index (BMI) z-score, waist circumference, and systolic blood pressure (SBP) were positively associated with increased left, right, and average cIMT, whereas diastolic blood pressure was positively associated only with increased left and average cIMT (p<0.05). In multivariate logistic regression analyses increased left cIMT was positively associated to BMI z-score and SBP, and increased average cIMT was only positively associated to SBP (p<0.05). BMI z-score and SBP were the strongest risk factors for increased cIMT.

Effects of Therapy with Maraviroc on the Carotid Intima Media Thickness in HIV-1/HCV Co-infected Patients

PubMed Central

MAGGI, PAOLO; BRUNO, GIUSEPPE; PERILLI, FRANCESCO; SARACINO, ANNALISA; VOLPE, ANNA; SANTORO, CARMEN; LADISA, NICOLETTA; ANGARANO, GIOACCHINO

2017-01-01

Aim: To evaluate, in human immunodeficiency virus-hepatitis C virus co-infected patients, the impact of C-C chemokine receptor type 5 (CCR5) antagonist maraviroc-based antiretroviral therapy on the carotid intima media thickness and on atheromasic plaques. Patients and Methods: In this pilot prospective study, 12 HIV-HCV co-infected patients underwent color-Doppler ultrasonography before and 48 weeks after switching to a dual therapy based on maraviroc plus protease inhibitors boosted with ritonavir. Changes of intima media thickness, inflammatory and endothelial adhesion biomarkers levels, Veterans Aging Cohort Study index and Framingham risk score were evaluated. Results: At baseline 11 (91.6%) patients showed pathological ultrasonographic findings. After 48 weeks, two patients showed an amelioration of intima media thickness. Of the remaining patients with plaques, four showed a reduction of the previously diagnosed plaque; no patients worsened. Conclusion: Our data suggest that CCR5 inhibition could reduce the development of atherosclerosis especially in the non-calcific stage and could play an important role in the blockade of atheromasic plaque progression. PMID:28064231

Effects of Therapy with Maraviroc on the Carotid Intima Media Thickness in HIV-1/HCV Co-infected Patients.

PubMed

Maggi, Paolo; Bruno, Giuseppe; Perilli, Francesco; Saracino, Annalisa; Volpe, Anna; Santoro, Carmen; Ladisa, Nicoletta; Angarano, Gioacchino

2017-01-02

To evaluate, in human immunodeficiency virus-hepatitis C virus co-infected patients, the impact of C-C chemokine receptor type 5 (CCR5) antagonist maraviroc-based antiretroviral therapy on the carotid intima media thickness and on atheromasic plaques. In this pilot prospective study, 12 HIV-HCV co-infected patients underwent color-Doppler ultrasonography before and 48 weeks after switching to a dual therapy based on maraviroc plus protease inhibitors boosted with ritonavir. Changes of intima media thickness, inflammatory and endothelial adhesion biomarkers levels, Veterans Aging Cohort Study index and Framingham risk score were evaluated. At baseline 11 (91.6%) patients showed pathological ultrasonographic findings. After 48 weeks, two patients showed an amelioration of intima media thickness. Of the remaining patients with plaques, four showed a reduction of the previously diagnosed plaque; no patients worsened. Our data suggest that CCR5 inhibition could reduce the development of atherosclerosis especially in the non-calcific stage and could play an important role in the blockade of atheromasic plaque progression. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

The Effect of Hypertension on the Transport of LDL Across the Deformable Arterial Wall

NASA Astrophysics Data System (ADS)

Dabagh, Mahsa; Jalali, Payman

2010-05-01

The influences of increased endothelial cell turnover and deformation of the intima on the transport of low-density lipoprotein (LDL) under hypertension are investigated by applying a multilayered model of aortic wall. The thickness and properties of the endothelium, intima, internal elastic lamina (IEL), and media are affected by the transmural pressure. Navier-Stokes and Brinkman equations are applied for the transport of the transmural flow and the convective-diffusion equation is solved for LDL transport. LDL macromolecules enter the intima through leaky junctions, and then pass through the media layer where they permeate over the surface of smooth muscle cells (SMC). Uptake of LDL by cells is modeled through a uniform reaction evenly distributed in the macroscopically homogeneous media layer. The results show that transmural pressure significantly affects the LDL fluxes across the leaky junction, the intima, fenestral pores in the IEL, and the media layer. Many realistic predictions including the proper magnitudes for the permeability of endothelium and intimal layers, and the hydraulic conductivity of all layers as well as their trends with pressure are predicted by the present model.

Seismic wave triggering of nonvolcanic tremor, episodic tremor and slip, and earthquakes on Vancouver Island

NASA Astrophysics Data System (ADS)

Rubinstein, Justin L.; Gomberg, Joan; Vidale, John E.; Wech, Aaron G.; Kao, Honn; Creager, Kenneth C.; Rogers, Garry

2009-02-01

We explore the physical conditions that enable triggering of nonvolcanic tremor and earthquakes by considering local seismic activity on Vancouver Island, British Columbia during and immediately after the arrival of large-amplitude seismic waves from 30 teleseismic and 17 regional or local earthquakes. We identify tremor triggered by four of the teleseismic earthquakes. The close temporal and spatial proximity of triggered tremor to ambient tremor and aseismic slip indicates that when a fault is close to or undergoing failure, it is particularly susceptible to triggering of further events. The amplitude of the triggering waves also influences the likelihood of triggering both tremor and earthquakes such that large amplitude waves triggered tremor in the absence of detectable aseismic slip or ambient tremor. Tremor and energy radiated from regional/local earthquakes share the same frequency passband so that tremor cannot be identified during these smaller, more frequent events. We confidently identify triggered local earthquakes following only one teleseism, that with the largest amplitude, and four regional or local events that generated vigorous aftershock sequences in their immediate vicinity. Earthquakes tend to be triggered in regions different from tremor and with high ambient seismicity rates. We also note an interesting possible correlation between large teleseismic events and episodic tremor and slip (ETS) episodes, whereby ETS events that are "late" and have built up more stress than normal are susceptible to triggering by the slight nudge of the shaking from a large, distant event, while ETS events that are "early" or "on time" are not.

Sensorineural Hearing Impairment and Subclinical Atherosclerosis in Rheumatoid Arthritis Patients Without Traditional Cardiovascular Risk Factors

PubMed Central

MACIAS-REYES, Hector; DURAN-BARRAGAN, Sergio; CARDENAS-CONTRERAS, Cynthia R.; CHAVEZ-MARTIN, Cesar G.; GOMEZ-BAÑUELOS, Eduardo; NAVARRO-HERNANDEZ, Rosa E.; YANOWSKY-GONZALEZ, Carlos O.; GONZALEZ-LOPEZ, Laura; GAMEZ-NAVA, Jorge I.

2016-01-01

Objectives This study aims to evaluate the association of hearing impairment with carotid intima-media thickness and subclinical atherosclerosis in rheumatoid arthritis (RA) patients. Patients and methods A total of 41 RA patients (2 males, 39 females; mean age 46.5±10.2 years; range 20 to 63 years) with no known traditional cardiovascular risk factors were included. Routine clinical and laboratory assessments for RA patients were performed. Pure tone air (250-8000 Hz) and bone conduction (250-6000 Hz) thresholds were obtained, tympanograms and impedance audiometry were conducted. Sensorineural hearing impairment was defined if the average thresholds were ≥25 decibels. Carotid intima-media thickness was assessed and classified with a cut-off point of 0.6 mm. Results Thirteen patients (31.7%) had normal audition, while 28 (68.3%) had hearing impairment. Of these, 22 had bilateral sensorineural hearing impairment. Four patients had conductive hearing impairment (right in three patients and left in one patient). Patients with sensorineural hearing impairment had increased carotid intima-media thickness in the media segment of carotid common artery compared to patients with normal hearing (right ear p=0.007; left ear p=0.075). Thickening of the carotid intima-media thickness was associated with sensorineural hearing impairment in RA patients. Conclusion Rheumatoid arthritis patients should be evaluated by carotid intima-media thickness as a possible contributing factor of hearing impairment in patients without cardiovascular risk factors. PMID:29900940

Serum Carotenoids Reduce Progression of Early Atherosclerosis in the Carotid Artery Wall among Eastern Finnish Men

PubMed Central

Karppi, Jouni; Kurl, Sudhir; Ronkainen, Kimmo; Kauhanen, Jussi; Laukkanen, Jari A.

2013-01-01

Background Several previous epidemiologic studies have shown that high blood levels of carotenoids may be protective against early atherosclerosis, but results have been inconsistent. We assessed the association between atherosclerotic progression, measured by intima-media thickness of the common carotid artery wall, and serum levels of carotenoids. Methods We studied the effect of carotenoids on progression of early atherosclerosis in a population-based study. The association between concentrations of serum carotenoids, and intima-media thickness of the common carotid artery wall was explored in 840 middle-aged men (aged 46–65 years) from Eastern Finland. Ultrasonography of the common carotid arteries were performed at baseline and 7-year follow-up. Serum levels of carotenoids were analyzed at baseline. Changes in mean and maximum intima media thickness of carotid artery wall were related to baseline serum carotenoid levels in covariance analyses adjusted for covariates. Results In a covariance analysis with adjustment for age, ultrasound sonographer, maximum intima media thickness, examination year, body mass index, systolic blood pressure, smoking, physical activity, serum LDL cholesterol, family history of coronary heart disease, antihypertensive medication and serum high sensitivity C-reactive protein, 7-year change in maximum intima media thickness was inversely associated with lycopene (p = 0.005), α-carotene (p = 0.002) and β-carotene (p = 0.019), respectively. Conclusions The present study shows that high serum concentrations of carotenoids may be protective against early atherosclerosis. PMID:23700460

Association of morning blood pressure surge with carotid intima-media thickness and cardiac dysfunction in patients with cardiac syndrome-X.

PubMed

Mahfouz, Ragab A; Goda, Mohammad; Galal, Islam; Ghareb, Mohamed S

2018-05-23

Background & hypothesis: We hypothesized that exaggerated morning blood pressure surge, may contribute in cardiac dysfunction and arterial stiffness in patients with cardiac syndrome X. Thus we investigated the impact of morning blood pressure surge on cardiac function and carotid intima-media thickness in subjects with cardiac syndrome X. We studied patients with cardiac syndrome X using ambulatory blood pressure monitoring and investigated the association of morning blood pressure surge with carotid intima thickness, left atrial volume index and left ventricular filling (E/e'). Seventy patients with cardiac syndrome X were enrolled for the study and compared with 70 age and sex matched controls. Patients with cardiac syndrome X were stratified based on the systolic morning blood pressure surge value of control subjects to patients with exaggerated blood pressure surge (n = 42) and those with normal morning blood pressure surge (n = 28). Basal heart rate (p < .05), high sensitive C-reactive protein (p < .01), left atrial volume index (p < .01), E/e' (p < .01); carotid intima-media thickness (p < .001) and percentage of detected plaque (p < .005) were significantly higher in patients with exaggerated morning blood pressure surge group than those with morning blood pressure surge group. Morning blood pressure surge was significantly correlated with carotid intima-media thickness, high sensitive C-reactive protein, left atrial volume index and E/e' ratio in patients with cardiac syndrome X. In multivariate analysis, exaggerated morning blood pressure surge was the only independent predictor of increased carotid intima-media thickness (OR = 2.379; p < .001), and diastolic dysfunction (OR = 2.464; p < .001) in patients with cardiac syndrome X. Our data suggest that excessive morning blood pressure surge is an independent predictor for arterial stiffness and diastolic dysfunction in patients with cardiac syndrome X.

Thicker carotid intima-media thickness and increased plasma VEGF levels suffered by post-acute thrombotic stroke patients.

PubMed

Yueniwati, Yuyun; Darmiastini, Ni Komang; Arisetijono, Eko

2016-01-01

Atherosclerosis causes reduction of the oxygen supply to structures in the far arterial wall, provoking the release of factors that drive angiogenesis of vasa vasorum, including VEGF. Other studies have revealed the inflammatory response in atherosclerosis and the role of platelet factor 4 (PF4) as an anti-angiogenic chemokine through the inhibition of VEGF. This cross-sectional study aims at measuring the effect of atherosclerosis assessed through carotid intima-media thickness (CIMT) against plasma VEGF levels in patients with post-acute thrombotic stroke. CIMT was assessed sonographically using GE Logiq S6 with 13 MHz frequency linear probe. VEGF-A plasma levels were measured using enzyme-linked immunosorbent assay (ELISA) method. Differences among variables were compared statistically. The data were analyzed using Pearson correlation. A total of 25 patients with post-acute thrombotic stroke were identified in days 7 to 90. CIMT thickening was indicated in 88% of patients (1.202 ± 0.312 mm), while an increase in plasma VEGF was identified in all patients (178.28 ± 93.96 ng/mL). There was no significant correlation between CIMT and plasma VEGF levels in patients with post-acute thrombotic stroke ( p =0.741). A significant correlation was recognized between CIMT and total cholesterol ( p =0.029) and low-density lipoprotein ( p =0.018). There were no significant correlations between CIMT and plasma VEGF levels in patients with post-acute thrombotic stroke. However, plasma VEGF increased in patients with thrombotic stroke. CIMT measurement is a promising noninvasive modality to assess the vascular condition of patients with stroke and diabetes, while plasma VEGF cannot specifically assess vascular condition as it can be triggered by ischemic conditions in tissues of the whole body.

Microbiota-Dependent Marker TMAO Is Elevated in Silent Ischemia but Is Not Associated With First-Time Myocardial Infarction in HIV Infection.

PubMed

Haissman, Judith M; Knudsen, Andreas; Hoel, Hedda; Kjær, Andreas; Kristoffersen, Ulrik S; Berge, Rolf K; Katzenstein, Terese L; Svardal, Asbjørn; Ueland, Thor; Aukrust, Pål; Lebech, Anne-Mette; Nielsen, Susanne D; Trøseid, Marius

2016-02-01

HIV infection is associated with increased risk of coronary heart disease beyond that explained by traditional risk factors, and altered gut microbiota has been proposed as a potential trigger. Trimethylamine-N-oxide (TMAO) is a proatherogenic substance formed in the liver from trimethylamine, exclusively generated by gut microbiota from dietary phosphatidylcholine. We aimed to investigate whether TMAO is associated with subclinical and clinical coronary heart disease in HIV infection. Two previously described cohorts were examined as follows: (1) cross-sectional cohort of HIV-infected persons and uninfected controls with known atherosclerotic plaque burden as assessed by myocardial perfusion scintigraphy, coronary artery calcium score, and intima-media thickness and (2) nested case-control study of HIV-infected persons with first-time myocardial infarction (MI) compared with HIV-infected persons without MI, assessed at 4 time points from before initiation of antiretroviral therapy (ART) to last sample before the case's MI (median: 51, range: 0-239 days). There was no difference in plasma TMAO when comparing HIV-infected persons and uninfected controls. TMAO was elevated in HIV-infected persons with myocardial perfusion defects but was not associated with coronary artery calcium score, intima media thickness, or Framingham risk score. In the nested case control study, plasma TMAO was not associated with first-time MI. However, TMAO increased after ART introduction and was associated with the use of protease inhibitors in both cohorts. TMAO was elevated in HIV-infected persons with myocardial perfusion defects, but was not associated with first-time MI. Our data question TMAO as a useful biomarker of cardiovascular risk in HIV infection, at least in ART-treated individuals.

[Livedo racemosa generalisata. Clinical aspects and histopathology of obliterating arteriolopathy with CNS involvement].

PubMed

Marsch, W C; Muckelmann, R

1985-06-01

The histopathology of Sneddon's syndrome (livedo racemosa generalisata and cerebrovascular defects) is characterized by a thickened intima with subsequent narrowing of the lumen of ascending arterioles in the upper subcutaneous tissue and deep dermis. Ultrastructurally, migrating medial smooth muscle cells with plenty of intermediate filaments colonize the subendothelial intimal space ("intima proliferation").

Real-time measurement system for the evaluation of the intima media thickness with a new edge detector.

PubMed

Faita, Francesco; Gemignani, Vincenzo; Bianchini, Elisabetta; Giannarelli, Chiara; Demi, Marcello

2006-01-01

The evaluation of the intima media thickness (IMT) of the common carotid artery (CCA) with B-mode ultrasonography represents an important index of cardiovascular risk. The IMT is defined as the distance between the leading edge of the lumen-intima interface and the leading edge of the media-adventitia interface. In order to evaluate the IMT, it is necessary to locate such edges. In this paper we developed an automatic real-time system to evaluate the IMT based on the first order absolute moment (FOAM), which is used as an edge detector, and on a pattern recognition approach. The IMT measurements were compared with manual measurements. We used regression analysis and Bland-Altman analysis to compare the results.

ELM mitigation with pellet ELM triggering and implications for PFCs and plasma performance in ITER

DOE PAGES

Baylor, Larry R.; Lang, P. T.; Allen, Steve L.; ...

2014-10-05

The triggering of rapid small edge localized modes (ELMs) by high frequency pellet injection has been proposed as a method to prevent large naturally occurring ELMs that can erode the ITER plasma facing components. Deuterium pellet injection has been used to successfully demonstrate the on-demand triggering of edge localized modes (ELMs) at much higher rates and with much smaller intensity than natural ELMs. The proposed hypothesis for the triggering mechanism of ELMs by pellets is the local pressure perturbation resulting from reheating of the pellet cloud that can exceed the local high-n ballooning mode threshold where the pellet is injected.more » Nonlinear MHD simulations of the pellet ELM triggering show destabilization of high-n ballooning modes by such a local pressure perturbation. A review of the recent pellet ELM triggering results from ASDEX Upgrade (AUG), DIII-D, and JET reveals that a number of uncertainties about this ELM mitigation technique still remain. These include the heat flux impact pattern on the divertor and wall from pellet triggered and natural ELMs, the necessary pellet size and injection location to reliably trigger ELMs, and the level of fueling to be expected from ELM triggering pellets and synergy with larger fueling pellets. The implications of these issues for pellet ELM mitigation in ITER and its impact on the PFCs are presented along with the design features of the pellet injection system for ITER.« less

ELM mitigation with pellet ELM triggering and implications for PFCs and plasma performance in ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baylor, Larry R.; Lang, P.; Allen, S. L.

2015-08-01

The triggering of rapid small edge localized modes (ELMs) by high frequency pellet injection has been proposed as a method to prevent large naturally occurring ELMs that can erode the ITER plasma facing components (PFCs). Deuterium pellet injection has been used to successfully demonstrate the on-demand triggering of edge localized modes (ELMs) at much higher rates and with much smaller intensity than natural ELMs. The proposed hypothesis for the triggering mechanism of ELMs by pellets is the local pressure perturbation resulting from reheating of the pellet cloud that can exceed the local high-n ballooning mode threshold where the pellet ismore » injected. Nonlinear MHD simulations of the pellet ELM triggering show destabilization of high-n ballooning modes by such a local pressure perturbation.A review of the recent pellet ELM triggering results from ASDEX Upgrade (AUG), DIII-D, and JET reveals that a number of uncertainties about this ELM mitigation technique still remain. These include the heat flux impact pattern on the divertor and wall from pellet triggered and natural ELMs, the necessary pellet size and injection location to reliably trigger ELMs, and the level of fueling to be expected from ELM triggering pellets and synergy with larger fueling pellets. The implications of these issues for pellet ELM mitigation in ITER and its impact on the PFCs are presented along with the design features of the pellet injection system for ITER.« less

[The inhibitive effect produced by local perfusion of tanshinone IIA nanoparticle on neointimal hyperplasia of rabbit carotid artery following intimal denudation].

PubMed

Liang, Ling; Chen, Yucheng; Xiong, Subin; Zeng, Zhi; Sun, Mingliang; Zhang, Haihong

2007-08-01

Tanshinone IIA nanoparticles were constructed and perfused in rabbit's right carotid after intimal denudation with ballon. Localization and retention at different time points of the coumarin-labeled drug nanoparticles were evaluated under laser confocal microscope. Nanoparticles were seen in the three layers of the cross-section artery. At 7 days, they were mainly deposited in the medial layer, while the deposition was generally observed in the adventitia and media at 14 days and 28 days. In the Tanshinone IIA nanoparticle study, a significant reduction of the neo-intimal hyperplasia was noted by comparing the intimal area and the intima-media ratio in the three groups. And the PLGA nanoparticles appeared to be fully biocompatible. As a result, the local administration of the nanoparticles with incorporated Tanshinone IIA showed not only the preventive effects, but aslo the high absorption and good biocompatability in the whole arterial wall.

Association of V249I and T280M variants of fractalkine receptor CX3CR1 with carotid intima-media thickness in a mexican population with type 2 diabetes.

PubMed

Gómez-Díaz, Rita A; Gutiérrez, Jorge; Contreras-Rodriguez, Alicia; Valladares-Salgado, Adán; Tanus-Hajj, Janet; Mondragón-González, Rafael; Talavera, Juan O; Mejía-Benitez, María Aurora; García-Mena, Jaime; Cruz, Miguel; Wacher, Niels H

2017-01-01

To evaluate the association of the V249I and T280M variants of CX3CR1 fractalkine gene with carotid intima-media thickness in Mexican subjects with and without type 2 diabetes. We analyzed the V249I and T280M variants of the CX3CR1 receptor by TaqMan assays in 111 subjects with type 2 diabetes and 109 healthy controls. Hemoglobin A1c, glucose, and lipid profile were determined. A significant increase in carotid intima-media thickness was observed in type 2 diabetes patients (0.979 ± 0.361 mm) compared to healthy controls (0.588 ± 0.175 mm). In subjects carrying the MM variant of the T280M polymorphism, hemoglobin A1c was higher (p = 0.008). Classic risk factors for atherosclerosis showed no differences between carriers of the T280M and V249I variants. Controls with the II249 genotype associated with carotid intima-media thickness (0.747 ± 0.192 mm; p = 0.041), and this difference remained significant even after adjusting factors such as age, gender, and body mass index (OR: 7.7; 95% CI: 1.269-47.31; p = 0.027). V249I genotype of the fractalkine receptor showed a protector role in patients with type 2 diabetes. The T280M genotype is associated with increased carotid intima-media thickness in Mexican individuals with or without type 2 diabetes.

Evaluation of TGF beta1 expression and comparison the thickness of different aorta layers in experimental diabetes.

PubMed

Cuce, G; Kalkan, S S; Esen, H H

2011-01-01

It was aimed to investigate the effects of experimental diabetes on TGF beta1 expression and tunica intima and media thickness in abdominal and thoracic aorta. Fourteen three months old female rats were divided into two groups, non-diabetic and streptozotocin (STZ) induced diabetic group. Hematoxylin-Eosin and Verhoeff's Van Gieson elastic staining and TGF beta1 immunohistochemistry staining were performed. Abdominal and thoracic intima and media thickness of aortas were measured with the oculometer. Evaluation of intima and media thickness measurements showed no significant statistical differences between non-diabetic and diabetic groups. TGF beta1 expression increased significantly in thoracic diabetic (TD) group. The 60 day duration of diabetes is not sufficiently enough time for the development of pathological changes that could lead to thickening in aortic intima-media layers. TGF beta1 expression was negative in the abdominal aorta that can predispose to the development of atherosclerosis, which could develop overtime. This finding may be interpreted as an appropriate basis for the development of atherosclerosis. In the thoracic aorta TGF beta1 may coordinate cellular events such as tissue repair (Fig. 5, Ref. 23).

In vivo detection of macrophages in a rabbit atherosclerotic model by time-resolved laser-induced fluorescence spectroscopy

PubMed Central

Marcu, Laura; Fang, Qiyin; Jo, Javier A.; Papaioannou, Thanassis; Dorafshar, Amir; Reil, Todd; Qiao, Jian-Hua; Baker, J. Dennis; Freischlag, Julie A.; Fishbein, Michael C.

2007-01-01

Accumulation of numerous macrophages in the fibrous cap is a key identifying feature of plaque inflammation and vulnerability. This study investigates the use of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) as a potential tool for detection of macrophage foam cells in the intima of atherosclerotic plaques. Experiments were conducted in vivo on 14 New Zealand rabbits (6 control, 8 hypercholesterolemic) following aortotomy to expose the intimal luminal surface of the aorta. Tissue autofluorescence was induced with a nitrogen pulse laser (337 nm, 1 ns). Lesions were histologically classified by the percent of collagen or macrophage foam cells as well as thickness of the intima. Using parameters derived from the time-resolved fluorescence emission of plaques, we determined that intima rich in macrophage foam cells can be distinguished from intima rich in collagen with high sensitivity (>85%) and specificity (>95%). This study demonstrates, for the first time, that a time-resolved fluorescence-based technique can differentiate and demark macrophage content versus collagen content in vivo. Our results suggest that TR-LIFS technique can be used in clinical applications for identification of inflammatory cells important in plaque formation and rupture. PMID:16039283

In vivo detection of macrophages in a rabbit atherosclerotic model by time-resolved laser-induced fluorescence spectroscopy.

PubMed

Marcu, Laura; Fang, Qiyin; Jo, Javier A; Papaioannou, Thanassis; Dorafshar, Amir; Reil, Todd; Qiao, Jian-Hua; Baker, J Dennis; Freischlag, Julie A; Fishbein, Michael C

2005-08-01

Accumulation of numerous macrophages in the fibrous cap is a key identifying feature of plaque inflammation and vulnerability. This study investigates the use of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) as a potential tool for detection of macrophage foam cells in the intima of atherosclerotic plaques. Experiments were conducted in vivo on 14 New Zealand rabbits (6 control, 8 hypercholesterolemic) following aortotomy to expose the intimal luminal surface of the aorta. Tissue autofluorescence was induced with a nitrogen pulse laser (337 nm, 1 ns). Lesions were histologically classified by the percent of collagen or macrophage foam cells as well as thickness of the intima. Using parameters derived from the time-resolved fluorescence emission of plaques, we determined that intima rich in macrophage foam cells can be distinguished from intima rich in collagen with high sensitivity (>85%) and specificity (>95%). This study demonstrates, for the first time, that a time-resolved fluorescence-based technique can differentiate and demark macrophage content versus collagen content in vivo. Our results suggest that TR-LIFS technique can be used in clinical applications for identification of inflammatory cells important in plaque formation and rupture.

Change in Elasticity Caused by Flow-Mediated Dilation Measured Only for Intima-Media Region of Brachial Artery

NASA Astrophysics Data System (ADS)

Sugimoto, Masataka; Hasegawa, Hideyuki; Kanai, Hiroshi

2005-08-01

Endothelial dysfunction is considered to be an initial step of arteriosclerosis [R. Ross: N. Engl. J. Med. 340 (2004) 115]. For the assessment of the endothelium function, brachial artery flow-mediated dilation (FMD) caused by increased blood flow has been evaluated with ultrasonic diagnostic equipment. In the case of conventional methods, the change in artery diameter caused by FMD is measured [M. Hashimoto et al.: Circulation 92 (1995) 3431]. Although the arterial wall has a layered structure (intima, media, and adventitia), such a structure is not taken into account in conventional methods because the change in diameter depends on the characteristic of the entire wall. However, smooth muscle present only in the media contributes to FMD, whereas the collagen-rich hard adventitia does not contribute. In this study, we measure the change in elasticity of only the intima-media region including smooth muscle using the phased tracking method [H. Kanai et al.: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43 (1996) 791]. From the change in elasticity, FMD measured only for the intima-media region by our proposed method was found to be more sensitive than that measured for the entire wall by the conventional method.

Growth hormone (GH) and atherosclerosis: changes in morphology and function of major arteries during GH treatment.

PubMed

Pfeifer, M; Verhovec, R; Zizek, B

1999-04-01

Patients with hypopituitarism have increased carotid artery intima-media thickness and reduced arterial distensibility. The effect of 2 years of growth hormone (GH) replacement therapy on these parameters was studied in 11 GH-deficient men (age range, 24-49 years) with hypopituitarism and compared with 12 healthy, age-matched men with no evidence of pituitary or vascular disease. Before treatment the intima-media of the common carotid arteries and the carotid bifurcations were significantly thicker in patients (P < 0.001) than in the control group. Treatment with GH normalized the intima-media thickness of the common carotid artery within 6 months and of the carotid bifurcation within 3 months. The changes in intima-media thickness of the carotid artery were negatively correlated with changes in serum levels of insulin-like growth factor I during treatment. There was a significant improvement in flow-mediated, endothelium-dependent dilation of the brachial artery at 3 months, which was sustained at 6, 18 and 24 months of GH treatment (P < 0.05). Thus, GH replacement therapy in GH-deficient men reverses early morphological and functional atherosclerotic changes in major arteries, and may reduce rates of vascular morbidity and mortality.

Cardiovascular Structure and Function in Children With Middle Aortic Syndrome and Renal Artery Stenosis.

PubMed

Rumman, Rawan K; Slorach, Cameron; Hui, Wei; Matsuda-Abedini, Mina; Langlois, Valerie; Radhakrishnan, Seetha; Lorenzo, Armando J; Amaral, Joao; Mertens, Luc; Parekh, Rulan S

2017-12-01

Middle aortic syndrome (MAS) is a narrowing of the abdominal aorta, often in conjunction with renal artery stenosis (RAS). Structure and function of the cardiovascular system are not well understood. In a prospective cross-sectional study, 35 children with MAS or RAS or both (MAS/RAS) were compared with 140 age-, sex-, and body surface area-matched healthy children. Vascular assessment included carotid intima-media thickness and carotid distensibility using B-mode ultrasound and central and peripheral pulse wave velocities using applanation tonometry. Left ventricular structure and function were assessed by 2-dimensional and speckle-tracking echocardiography. Children with MAS or RAS were 12.5±3.0 years old at enrollment, and 50% were men. Carotid intima-media thickness (0.54±0.10 versus 0.44±0.05 mm; P <0.001) and central pulse wave velocities (5.58±1.83 versus 5.00±0.90 m/s; P =0.01) were significantly higher in children with disease compared with healthy children; however, after adjustment for systolic blood pressure z score, only carotid intima-media thickness remained significantly higher in the MAS/RAS group compared with the controls (β=0.07 [0.03, 0.10]). Peripheral pulse wave velocities and carotid distensibility were normal. Children with disease had significantly increased left ventricular mass and changes in diastolic function (lower E/a ratio and lower e' velocities). Systolic parameters, including ejection fraction, global longitudinal and circumferential strain, were similar to controls. Our findings demonstrate that children with MAS or RAS have evidence of carotid and left ventricular remodeling, without peripheral arterial involvement, which suggests a localized disease process. Left ventricular systolic function is preserved; however, subtle changes in diastolic function are observed. Carotid vessel changes are consistent with a 5- to 10-year aging, which underscores the importance of blood pressure control. © 2017 American Heart Association, Inc.

Classification of coronary artery tissues using optical coherence tomography imaging in Kawasaki disease

NASA Astrophysics Data System (ADS)

Abdolmanafi, Atefeh; Prasad, Arpan Suravi; Duong, Luc; Dahdah, Nagib

2016-03-01

Intravascular imaging modalities, such as Optical Coherence Tomography (OCT) allow nowadays improving diagnosis, treatment, follow-up, and even prevention of coronary artery disease in the adult. OCT has been recently used in children following Kawasaki disease (KD), the most prevalent acquired coronary artery disease during childhood with devastating complications. The assessment of coronary artery layers with OCT and early detection of coronary sequelae secondary to KD is a promising tool for preventing myocardial infarction in this population. More importantly, OCT is promising for tissue quantification of the inner vessel wall, including neo intima luminal myofibroblast proliferation, calcification, and fibrous scar deposits. The goal of this study is to classify the coronary artery layers of OCT imaging obtained from a series of KD patients. Our approach is focused on developing a robust Random Forest classifier built on the idea of randomly selecting a subset of features at each node and based on second- and higher-order statistical texture analysis which estimates the gray-level spatial distribution of images by specifying the local features of each pixel and extracting the statistics from their distribution. The average classification accuracy for intima and media are 76.36% and 73.72% respectively. Random forest classifier with texture analysis promises for classification of coronary artery tissue.

Comparative study to assess whether high sensitive C-reactive protein and carotid intima media thickness improve the predictive accuracy of exercise stress testing for coronary artery disease in perimenopausal women with typical angina.

PubMed

Sinha, Dhurjati Prasad; Das, Munna; Banerjee, Amal Kumar; Ahmed, Shageer; Majumdar, Sonali

2008-02-01

Anginal symptoms are less predictive of abnormal coronary anatomy in women. The diagnostic accuracy of exercise treadmill test for obstructive coronary artery disease is less in young and middle aged women. High sensitive C-reactive protein has shown a strong and consistent relationship to the risk of incident cardiovascular events. Carotid intima media thickness is a non-invasive marker of atherosclerosis burden and also predicts prognosis in patients with coronary artery disease. We investigated whether incorporation of high sensitive C-reactive protein and carotid intima media thickness along with exercise stress results improved the predictive accuracy in perimenopausal non-diabetic women subset. Fifty perimenopausal non-diabetic patients (age 45 +/- 7 years) presenting with typical angina were subjected to treadmill test (Bruce protocol). Also carotid artery images at both sides of neck were acquired by B-mode ultrasound and carotid intima media thickness were measured. High sensitive C-reactive protein was measured. Of 50 patients, 22 had a positive exercise stress result. Coronary angiography done in all 50 patients revealed coronary artery disease in 10 patients with positive exercise stress result and in 4 patients with negative exercise stress result. Treadmill exercise stress test had a sensitivity of 71.4%, specificity of 66.7% and a negative predictive accuracy of 85.7% in this study group. High sensitive C-reactive protein in patients with documented coronary artery disease was not significantly different from those without coronary artery disease (4.8 +/- 0.9 mg/l versus 3.9 +/- 1.7 mg/l, p=NS). Also carotid intima media thickness was not significantly different between either of the groups with coronary artery disease positivity and negativity respectively (left: 1.25 +/- 0.55 versus 1.20 +/- 0.51 mm, p=NS; right:1.18 +/- 0.54 versus 1.15 +/- 0.41 mm, p=NS). High sensitive C-reactive protein and carotid intima media thickness were not helpful in further adding to the predictability of coronary artery disease in perimenopausal patients with typical angina as assessed by treadmill exercise stress test.

Morphology and Histology of the Ductus Receptaculi and Accessory Glands in the Reproductive Tract of the Female Cricket, Teleogryllus commodus

PubMed Central

Sturm, Robert

2008-01-01

The morphology and histology of the ductus receptaculi and accessory glands in females of the black field cricket, Teleogryllus commodus Walker (Orthoptera: Gryllidae) are described. Both are reproductive organs situated in the 7th and 8th abdominal segment that join the posterior part of the genital chamber. The ductus receptaculi is a long (up to 25 mm) homogeneous tube, and the accessory glands (total length: 4 to 12 mm) are a complex system of tubes and end lobes with various numbers of ramifications. Based on their external shapes the accessory glands may be subdivided into three distinct regions, a distal region mainly producing the gland's secretion, a middle conducting region, and a basal region serving for the storage and release of the secretory substances into the genital chamber of the female. In histological respects, both organs have an outer muscle coat followed by a basal lamina, one or two cell layers, the cuticular intima, and the inner lumen. The ductus receptaculi is subdivided into three histologically different regions. The region located adjacent to the receptaculum and the region neighbouring the terminal papilla consist of a single, epithelial cell layer that is not secretory. The epithelium of the middle region contains two cell layers, glandular cells and cuticula-forming cells, which are responsible for the production of the cuticular intima. The secretion of the gland cells is released into an extracellular cavity, through which it reaches the lumen via a complex network of canals running through the intima. The histology of the accessory glands is rather homogeneous among the different regions, as one layer of epithelial cells produces both the secretion and the cuticular intima. Histological variations in the distal, middle, and basal gland sections mainly concern the height of the epithelium, the thickness of the basal lamina and the cuticular intima as well as the variable presence of the outer muscle coat. In contrast to the ductus receptaculi, secretory substances produced by the accessory gland cells accumulate in the lumen by a diffusive permeation of the intima. PMID:20298118

Fasting glucose levels, incident diabetes, subclinical atherosclerosis and cardiovascular events in apparently healthy adults: A 12-year longitudinal study.

PubMed

Sitnik, Debora; Santos, Itamar S; Goulart, Alessandra C; Staniak, Henrique L; Manson, JoAnn E; Lotufo, Paulo A; Bensenor, Isabela M

2016-11-01

We aimed to study the association between fasting plasma glucose, diabetes incidence and cardiovascular burden after 10-12 years. We evaluated diabetes and cardiovascular events incidences, carotid intima-media thickness and coronary artery calcium scores in ELSA-Brasil (the Brazilian Longitudinal Study of Adult Health) baseline (2008-2010) of 1536 adults without diabetes in 1998. We used regression models to estimate association with carotid intima-media thickness (in mm), coronary artery calcium scores (in Agatston points) and cardiovascular events according to fasting plasma glucose in 1998. Adjusted diabetes incidence rate was 9.8/1000 person-years (95% confidence interval: 7.7-13.6/1000 person-years). Incident diabetes was positively associated with higher fasting plasma glucose. Fasting plasma glucose levels 110-125 mg/dL were associated with higher carotid intima-media thickness (β = 0.028; 95% confidence interval: 0.003-0.053). Excluding those with incident diabetes, there was a borderline association between higher carotid intima-media thickness and fasting plasma glucose 110-125 mg/dL (β = 0.030; 95% confidence interval: -0.005 to 0.065). Incident diabetes was associated with higher carotid intima-media thickness (β = 0.034; 95% confidence interval: 0.015-0.053), coronary artery calcium scores ⩾400 (odds ratio = 2.84; 95% confidence interval: 1.17-6.91) and the combined outcome of a coronary artery calcium scores ⩾400 or incident cardiovascular event (odds ratio = 3.50; 95% confidence interval: 1.60-7.65). In conclusion, fasting plasma glucose in 1998 and incident diabetes were associated with higher cardiovascular burden. © The Author(s) 2016.

Exposure to Violence and Carotid Artery Intima-Media Thickness in Mexican Women.

PubMed

Flores-Torres, Mario H; Lynch, Rebekka; Lopez-Ridaura, Ruy; Yunes, Elsa; Monge, Adriana; Ortiz-Panozo, Eduardo; Cantu-Brito, Carlos; Hauksdóttir, Arna; Valdimarsdóttir, Unnur; Lajous, Martín

2017-08-17

Violence against women has become a global public health threat. Data on the potential impact of exposure to violence on cardiovascular disease are scarce. We evaluated the association between exposure to violence and subclinical cardiovascular disease in 634 disease-free women from the Mexican Teachers' Cohort who responded to violence-related items from the Life Stressor Checklist and underwent measures of carotid artery intima-media thickness in 2012 and 2013. We defined exposure to violence as having ever been exposed to physical and/or sexual violence. Intima-media thickness was log-transformed, and subclinical carotid atherosclerosis was defined as intima-media thickness ≥0.8 mm or plaque. We used multivariable linear and logistic regression models adjusted for several potential confounders. Mean age was 48.9±4.3 years. Close to 40% of women reported past exposure to violence. The lifetime prevalence of sexual violence was 7.1%, and prevalence of physical violence was 23.5% (7.7% reported both sexual and physical violence). Relative to women with no history of violence, exposure to violence was associated with higher intima-media thickness (adjusted mean percentage difference=2.4%; 95% confidence interval 0.5, 4.3) and subclinical atherosclerosis (adjusted odds ratio=1.60; 95% confidence interval 1.10, 2.32). The association was stronger for exposure to physical violence, especially by mugging or physical assault by a stranger (adjusted mean % difference=4.6%; 95% confidence interval 1.8, 7.5, and odds ratio of subclinical carotid atherosclerosis=2.06; 95% confidence interval 1.22, 3.49). Exposure to violence, and in particular assault by a stranger, was strongly associated with subclinical cardiovascular disease in Mexican middle-aged women. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Intra- and extracellular magnesium levels and atheromatosis in haemodialysis patients.

PubMed

Tzanakis, Ioannis; Virvidakis, Kyriakos; Tsomi, Aggeliki; Mantakas, Emmanouel; Girousis, Nikolaos; Karefyllakis, Nektarios; Papadaki, Antonia; Kallivretakis, Nikolaos; Mountokalakis, Theodoros

2004-06-01

Traditional risk factors do not adequately explain the high prevalence of cardiovascular disease in patients with chronic renal insufficiency. Currently, there is a lot of evidence that hypomagnesaemia may play a significant role in the pathogenesis of cardiovascular diseases in general population. The aim of this study was to test the hypothesis that magnesium status in haemodialysis patients is related to the degree of atheromatosis of carotid arteries, as assessed by B-mode ultrasound. Intima-media thickness of both common carotids was assessed by B-mode ultrasound in 93 stable chronic haemodialysis patients and in 182 age- and sex-matched healthy controls. Intracellular magnesium as well as serum magnesium levels were obtained in the haemodialysis patients. Intracellular magnesium was estimated by determination of this ion in isolated peripheral lymphocytes. Haemodialysis patients had also a significantly higher mean common carotid intima-media thickness than controls (0.87+/-0.16 vs 0.76+/-0.13 mm, p < 0.001). Multivariate analysis revealed that in haemodialysis patients both serum magnesium and intracellular magnesium were negatively associated with common carotid intima-media thickness (p = 0.001 and p = 0.003 respectively). Significant associations between the age of the haemodialysis patients, the existence of diabetes mellitus as well as the serum calcium x serum phosphate product with common carotid intima-media thickness of haemodialysis patients were also observed. A strong negative association of both extracellular and intracellular magnesium with common carotid intima-media thickness exists in haemodialysis patients. The above finding suggests that magnesium may play an important protective role in the development and/or acceleration of arterial atherosclerosis in patients with chronic renal insufficiency.

Repeated Blood Pressure Measurements in Childhood in Prediction of Hypertension in Adulthood.

PubMed

Oikonen, Mervi; Nuotio, Joel; Magnussen, Costan G; Viikari, Jorma S A; Taittonen, Leena; Laitinen, Tomi; Hutri-Kähönen, Nina; Jokinen, Eero; Jula, Antti; Cheung, Michael; Sabin, Matthew A; Daniels, Stephen R; Raitakari, Olli T; Juonala, Markus

2016-01-01

Hypertension may be predicted from childhood risk factors. Repeated observations of abnormal blood pressure in childhood may enhance prediction of hypertension and subclinical atherosclerosis in adulthood compared with a single observation. Participants (1927, 54% women) from the Cardiovascular Risk in Young Finns Study had systolic and diastolic blood pressure measurements performed when aged 3 to 24 years. Childhood/youth abnormal blood pressure was defined as above 90th or 95th percentile. After a 21- to 31-year follow-up, at the age of 30 to 45 years, hypertension (>140/90 mm Hg or antihypertensive medication) prevalence was found to be 19%. Carotid intima-media thickness was examined, and high-risk intima-media was defined as intima-media thickness >90th percentile or carotid plaques. Prediction of adulthood hypertension and high-risk intima-media was compared between one observation of abnormal blood pressure in childhood/youth and multiple observations by improved Pearson correlation coefficients and area under the receiver operating curve. When compared with a single measurement, 2 childhood/youth observations improved the correlation for adult systolic (r=0.44 versus 0.35, P<0.001) and diastolic (r=0.35 versus 0.17, P<0.001) blood pressure. In addition, 2 abnormal childhood/youth blood pressure observations increased the prediction of hypertension in adulthood (0.63 for 2 versus 0.60 for 1 observation, P=0.003). When compared with 2 measurements, third observation did not provide any significant improvement for correlation or prediction (P always >0.05). A higher number of childhood/youth observations of abnormal blood pressure did not enhance prediction of adult high-risk intima-media thickness. Compared with a single measurement, the prediction of adult hypertension was enhanced by 2 observations of abnormal blood pressure in childhood/youth. © 2015 American Heart Association, Inc.

Earthquake triggering in southeast Africa following the 2012 Indian Ocean earthquake

NASA Astrophysics Data System (ADS)

Neves, Miguel; Custódio, Susana; Peng, Zhigang; Ayorinde, Adebayo

2018-02-01

In this paper we present evidence of earthquake dynamic triggering in southeast Africa. We analysed seismic waveforms recorded at 53 broad-band and short-period stations in order to identify possible increases in the rate of microearthquakes and tremor due to the passage of teleseismic waves generated by the Mw8.6 2012 Indian Ocean earthquake. We found evidence of triggered local earthquakes and no evidence of triggered tremor in the region. We assessed the statistical significance of the increase in the number of local earthquakes using β-statistics. Statistically significant dynamic triggering of local earthquakes was observed at 7 out of the 53 analysed stations. Two of these stations are located in the northeast coast of Madagascar and the other five stations are located in the Kaapvaal Craton, southern Africa. We found no evidence of dynamically triggered seismic activity in stations located near the structures of the East African Rift System. Hydrothermal activity exists close to the stations that recorded dynamic triggering, however, it also exists near the East African Rift System structures where no triggering was observed. Our results suggest that factors other than solely tectonic regime and geothermalism are needed to explain the mechanisms that underlie earthquake triggering.

Intravascular local gene transfer mediated by protein-coated metallic stent.

PubMed

Yuan, J; Gao, R; Shi, R; Song, L; Tang, J; Li, Y; Tang, C; Meng, L; Yuan, W; Chen, Z

2001-10-01

To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent. A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear-specific beta-galactosidase (Ad-beta gal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-beta gal viral stock (2 x 10(10) pfu/ml) for 3 min, and then implanted into the carotid arteries in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n = 4), 14 (n = 1) and 21 (n = 1) days after implantation, respectively. The beta-galactosidase expression was assessed by X-gal staining. The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the beta-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site. Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.

Kinetic modeling of low density lipoprotein oxidation in arterial wall and its application in atherosclerotic lesions prediction.

PubMed

Karimi, Safoora; Dadvar, Mitra; Modarress, Hamid; Dabir, Bahram

2013-01-01

Oxidation of low-density lipoprotein (LDL) is one of the major factors in atherogenic process. Trapped oxidized LDL (Ox-LDL) in the subendothelial matrix is taken up by macrophage and leads to foam cell generation creating the first step in atherosclerosis development. Many researchers have studied LDL oxidation using in vitro cell-induced LDL oxidation model. The present study provides a kinetic model for LDL oxidation in intima layer that can be used in modeling of atherosclerotic lesions development. This is accomplished by considering lipid peroxidation kinetic in LDL through a system of elementary reactions. In comparison, characteristics of our proposed kinetic model are consistent with the results of previous experimental models from other researches. Furthermore, our proposed LDL oxidation model is added to the mass transfer equation in order to predict the LDL concentration distribution in intima layer which is usually difficult to measure experimentally. According to the results, LDL oxidation kinetic constant is an important parameter that affects LDL concentration in intima layer so that existence of antioxidants that is responsible for the reduction of initiating rates and prevention of radical formations, have increased the concentration of LDL in intima by reducing the LDL oxidation rate. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Carotid intima-media thickness in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil): a narrative review.

PubMed

Santos, Eduardo Henrique Sena; Santos Neto, Pedro José Dos; Santos, Itamar de Souza

2018-01-01

Carotid intima-media thickness (CIMT), as measured by ultrasound, has been used in large studies as a non-invasive marker for subclinical atherosclerosis. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a cohort of 15,105 civil servants in six Brazilian cities that included CIMT evaluation in its baseline assessment. The aim of the present narrative review was to provide an overview of ELSA-Brasil CIMT articles published up to July 31, 2017. Narrative review of ELSA-Brasil CIMT studies using baseline assessment data. We searched PubMed for the terms "ELSA-Brasil" and "intima-media". This search yielded 21 published articles using CIMT data from the ELSA-Brasil baseline assessment, which were included in this review. We also present information about intima-media thickness assessment from ongoing onsite reevaluations of the study participants. Most published studies focused on the association with traditional and novel cardiovascular risk factors. Studies also presented information about the ELSA-Brasil CIMT protocol at baseline and CIMT value distribution in this large sample. Analyses on the ELSA-Brasil data led to important insights on CIMT interpretation and physiology. Besides the highlighted contributions which have already been made in this field, new data gathered during the ongoing third onsite assessment will enable investigation of substantially new research questions.

Convergent and Divergent Signaling in PAMP-Triggered Immunity and Effector-Triggered Immunity.

PubMed

Peng, Yujun; van Wersch, Rowan; Zhang, Yuelin

2018-04-01

Plants use diverse immune receptors to sense pathogen attacks. Recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors localized on the plasma membrane leads to PAMP-triggered immunity (PTI). Detection of pathogen effectors by intracellular or plasma membrane-localized immune receptors results in effector-triggered immunity (ETI). Despite the large variations in the magnitude and duration of immune responses triggered by different PAMPs or pathogen effectors during PTI and ETI, plasma membrane-localized immune receptors activate similar downstream molecular events such as mitogen-activated protein kinase activation, oxidative burst, ion influx, and increased biosynthesis of plant defense hormones, indicating that defense signals initiated at the plasma membrane converge at later points. On the other hand, activation of ETI by immune receptors localized to the nucleus appears to be more directly associated with transcriptional regulation of defense gene expression. Here, we review recent progress in signal transductions downstream of different groups of plant immune receptors, highlighting the converging and diverging molecular events.

Measurement of intima-media thickness of common carotid arteries using ultrasound in patients with familial and non-familial hypercholesterolaemia and correlation of intima-media thickness to obesity.

PubMed

Nafikudin, M; Nawawi, H; Muid, S; Annuar, R; Yusoff, K; Khalid, B A

2003-12-01

Ultrasonographic measurements of the intima-media thickness (IMT) of common carotid arteries (CCA) were taken in 50 patients with familial hypercholesterolaemia (FH) and 57 patients with non-familial hypercholesterolemia (NFH). The lipid profile, body mass index (BMI) and waist-hip ratio (WHR) of each patient were recorded. In FH patients, the IMT was significantly higher in overweight and elevated WHR subgroups compared to the normal with significant correlations between BMI and WHR to the IMT. In NFH patients, the IMT was significantly higher in the elevated WHR compared to the normal subgroup but the correlations between either BMI or WHR to IMT were insignificant. These suggest that the environmentally modified anthropometric indices may have an effect on atherosclerosis in genetically determined hypercholesterolaemia in FH patients.

FLOW MEDIATED DILATION AND CAROTID INTIMA MEDIA THICKNESS IN PATIENTS WITH CHRONIC GASTRITIS ASSOCIATED WITH HELICOBACTER PYLORI INFECTION.

PubMed

Judaki, Arezo; Norozi, Siros; Ahmadi, Mohammad Reza Hafezi; Ghavam, Samira Mis; Asadollahi, Khairollah; Rahmani, Asghar

2017-12-01

Endothelial dysfunction is one of the early stages of vascular diseases. The aim of this study was to investigate the endothelial dysfunction markers in patients with chronic gastritis associated with Helicobacter pylori (H. pylori) infection. By a cross sectional study, basic and clinical information of 120 participants (40 patients with positive H. pylori infection, 40 patients with negative H. pylori infection and 40 healthy people) were analyzed. Carotid intima media thickness and flow-mediated dilation levels were measured in all patients and controls. Soluble vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured with Elisa for all subjects. IgG level was assessed in chronic gastritis patients. The flow-mediated dilation level in patients with positive H. pylori infection (0.17%±0.09) was significantly lower than those with negative H. pylori infection (0.21% ±0.10, P<0.05) and compared to the control group (0.27% ±0.11, P<0.05). Carotid intima media thickness level in patients with positive H. pylori infection (0.58±0.13 mm) was significantly higher than those with negative H. pylori infection (0.48±0.32 mm, P<0.05) and compared to the control group (0.36±0.44mm, P<0.05). The mean level of sICAM-1 in positive H. pylori infection group (352.16±7.54 pg/mL) was higher than negative H. pylori infection group (332.64±8.75 pg/mL =0.75) and compared to the control group (236.32±12.43 pg/mL, P<0.05). A direct relationship was revealed between flow-mediated dilation and carotid intima media thickness changes and between sICAM-1 and sVCAM-1 associated with the level of H. pylori IgG in chronic gastritis. The levels of flow-mediated dilation, carotid intima media thickness and sICAM-1 were higher among patients with positive H. pylori infection. Patients with chronic gastritis associated with H. pylori infection are at risk of endothelial dysfunction due to flow-mediated dilation and carotid intima media thickness abnormalities and increased level of sICAM-1 and sVCAM-1.

UV-crosslinkable and thermo-responsive chitosan hybrid hydrogel for NIR-triggered localized on-demand drug delivery.

PubMed

Wang, Lei; Li, Baoqiang; Xu, Feng; Xu, Zheheng; Wei, Daqing; Feng, Yujie; Wang, Yaming; Jia, Dechang; Zhou, Yu

2017-10-15

Innovative drug delivery technologies based on smart hydrogels for localized on-demand drug delivery had aroused great interest. To acquire smart UV-crosslinkable chitosan hydrogel for NIR-triggered localized on-demanded drug release, a novel UV-crosslinkable and thermo-responsive chitosan was first designed and synthesized by grafting with poly N-isopropylacrylamide, acetylation of methacryloyl groups and embedding with photothermal carbon. The UV-crosslinkable unit (methacryloyl groups) endowed chitosan with gelation via UV irradiation. The thermo-responsive unit (poly N-isopropylacrylamide) endowed chitosan hydrogel with temperature-triggered volume shrinkage and reversible swelling/de-swelling behavior. The chitosan hybrid hydrogel embedded with photothermal carbon exhibited distinct NIR-triggered volume shrinkage (∼42% shrinkage) in response to temperature elevation as induced by NIR laser irradiation. As a demonstration, doxorubicin release rate was accelerated and approximately 40 times higher than that from non-irradiated hydrogels. The UV-crosslinkable and thermal-responsive hybrid hydrogel served as in situ forming hydrogel-based drug depot is developed for NIR-triggered localized on-demand release. Copyright © 2017 Elsevier Ltd. All rights reserved.

Remote Dynamic Earthquake Triggering in Shale Gas Basins in Canada and Implications for Triggering Mechanisms

NASA Astrophysics Data System (ADS)

Harrington, Rebecca M.; Liu, Yajing; Wang, Bei; Kao, Honn; Yu, Hongyu

2017-04-01

Here we investigate the occurrence of remote dynamic triggering in three sedimentary basins in Canada where recent fluid injection activity is correlated with increasing numbers of earthquakes. In efforts to count as many small, local earthquakes as possible for the statistical test of triggering, we apply a multi-station matched-filter detection method to continuous waveforms to detect uncataloged local earthquakes in 10-day time windows surrounding triggering mainshocks occurring between 2013-2015 with an estimated local peak ground velocity exceeding 0.01 cm/s. We count the number of earthquakes in 24-hour bins and use a statistical p-value test to determine if the changes in seismicity levels after the mainshock waves have passed are statistically significant. The p-value tests show occurrences of triggering following transient stress perturbations of < 10 kPa at all three sites that suggest local faults may remain critically stressed over periods similar to the time frame of our study ( 2 years) or longer, potentially due to maintained high pore pressures in tight shale formations following injection. The time window over which seismicity rates change varies at each site, with more delayed triggering occurring at sites where production history is longer. The observations combined with new modeling results suggest that the poroelastic response of the medium may be the dominant factor influencing instantaneous triggering, particularly in low-permeability tight shales. At sites where production history is longer and permeabilities have been increased, both pore pressure diffusion and the poroelastic response of the medium may work together to promote both instantaneous and delayed triggering. Not only does the interplay of the poroelastic response of the medium and pore pressure diffusion have implications for triggering induced earthquakes near injection sites, but it may be a plausible explanation for observations of instantaneous and delayed earthquake triggering in general.

[The effect of losartan on the intima-media thickness of carotid artery].

PubMed

Sönmez, Hulki Meltem; Turan, Filiz Canli; Köseoğlu, Kutsi

2008-06-01

There are findings about negative effects of angiotensin 1 (AT1) receptor stimulation at every stage of atherosclerosis formation. Recently, AT1 receptors, especially the effects of AT1 receptor antagonists on the regression of atherosclerosis, are being researched intensively. Measurement of carotid artery thickness has been accepted as a marker of atherosclerosis. In our study, we investigated the effect of AT1 receptor antagonist, losartan, on the carotid artery intima-media thickness of newly diagnosed hypertensive patients. We reached to 450 individuals by the stratified and random sampling method and measured their blood pressure to find out undiagnosed hypertensive patients. Fifty-one patients (mean age 54+/-9 years) were accepted to participate in our study. Forty-nine of them (33 women and 16 men) completed the study. After the measurements of the carotid artery intima-media thicknesses by B-mode Doppler ultrasonography, their blood tests were performed and arterial blood pressures were measured. Soon after, treatment with losartan as an antihypertensive agent was begun. All measurements were repeated on the eighth month of this therapy. The mean systolic and diastolic blood pressure of the cases were 167+/-14 mmHg and 102+/-8 mmHg, respectively. At the end of the eighth month these measurements regressed to 139+/-11 mmHg and 84+/-8 mmHg, respectively (p<0.05). Meaningful regression of carotid artery intima-media thickness was established. The mean regression was 0.10+/-0.19 mm (p=0.004) for women, 0.18+/-0.29 mm (p=0.007) for men and 0.13+/-0.23 mm (p<0.001) for the study population. No relation was seen between the carotid artery intima-media thickness and first systolic and diastolic blood pressure measurements of the patients (r=0.122, p=0.403 and r=0.032, p=0.828, respectively). We think that losartan should be recommended to use for protection against atherosclerosis at the young aged individuals that have multiple risks for atherosclerosis, other than hypertension.

The effects of vitamin D supplementation on proatherogenic inflammatory markers and carotid intima media thickness in subjects with metabolic syndrome: a randomized double-blind placebo-controlled clinical trial.

PubMed

Salekzamani, Shabnam; Bavil, Abolhassan Shakeri; Mehralizadeh, Hossein; Jafarabadi, Mohammad Asghari; Ghezel, Aymaral; Gargari, Bahram Pourghassem

2017-07-01

Metabolic syndrome may predispose to cardiovascular diseases. Since, in recent studies, vitamin D is advocated for cardioprotective roles, this study was designed to investigate the effects of vitamin D supplementation on proatherogenic inflammatory markers and common carotid intima media thickness in subjects with metabolic syndrome. This randomized double blind clinical trial was conducted in Tabriz, Iran. Eligible subjects (n = 80) with metabolic syndrome were recruited thorough advertisement and randomized to receive either vitamin D (50,000 IU/week) or matching placebo for 16 weeks. Interlukin-6, high sensitivity C-reactive protein, vascular cell adhesion molecule-1, E-selectin, and common carotid intima media thickness were measured at the beginning and end of the study. The study was registered at http://www.irct.ir (code: IRCT201409033140N14). Sixteen weeks supplementation with vitamin D increased median of serum 25-hydroxy vitamin D [25(OH)D] and mean calcium levels (p < 0.001) in the intervention group. There was also a significant difference in parathyroid hormone level at the end of the study (p < 0.001). Vitamin D treatment reduced IL-6 level after 16 weeks (p = 0.027). Compared to baseline, vascular cell adhesion molecule-1 and E-selectin levels decreased significantly in vitamin D treated subjects; however, there were no significant differences between two groups. No effect of vitamin D supplementation was observed in either common carotid intima media thickness or high sensitivity C-reactive protein concentrations at the end of the study (p > 0.05). Vitamin D supplementation improved some proatherogenic inflammatory markers in subjects with metabolic syndrome. No changes of high sensitivity C-reactive protein and carotid intima media thickness were shown after 16 weeks.

Sampling and Control Circuit Board for an Inertial Measurement Unit

NASA Technical Reports Server (NTRS)

Chelmins, David T (Inventor); Sands, Obed (Inventor); Powis, Richard T., Jr. (Inventor)

2016-01-01

A circuit board that serves as a control and sampling interface to an inertial measurement unit ("IMU") is provided. The circuit board is also configured to interface with a local oscillator and an external trigger pulse. The circuit board is further configured to receive the external trigger pulse from an external source that time aligns the local oscillator and initiates sampling of the inertial measurement device for data at precise time intervals based on pulses from the local oscillator. The sampled data may be synchronized by the circuit board with other sensors of a navigation system via the trigger pulse.

Histomorphometric study of brachiocephalic artery of Japanese quail

PubMed Central

Shariati, Sarah; Rahmanifar, Farhad; Tamadon, Amin

2015-01-01

Brachiocephalic arteries in quails are large arteries which are arising separately from the aortic arch. The aim of the present study was to determine the histomorphometric aspects of brachiocephalic arteries in the Japanese quail. The different layers of the brachiocephalic artery were studied quantitatively in 10, 20 and 60 days-old Japanese quail; (n = 6) and both sexes. Luminal diameter, thickness of the intima, media and adventitia, the percentage of the intima, media and adventitia, as compared with the total wall thickness were determined. It was found that luminal diameter and whole artery thickness increased by age (p < 0.05). In addition, the tunica media was the thickest layer, then tunica intima and at last tunica adventitia (p < 0.05). The muscularity of the right brachiocephalic artery was more than that of the left one (p < 0.05). Histomorphometric study of brachiocephalic arteries of Japanese quails showed that increasing of age causes increase of internal and external diameters of the artery and this increase in females was more than males. PMID:26893806

Histomorphometric study of brachiocephalic artery of Japanese quail.

PubMed

Shariati, Sarah; Rahmanifar, Farhad; Tamadon, Amin

2015-01-01

Brachiocephalic arteries in quails are large arteries which are arising separately from the aortic arch. The aim of the present study was to determine the histomorphometric aspects of brachiocephalic arteries in the Japanese quail. The different layers of the brachiocephalic artery were studied quantitatively in 10, 20 and 60 days-old Japanese quail; (n = 6) and both sexes. Luminal diameter, thickness of the intima, media and adventitia, the percentage of the intima, media and adventitia, as compared with the total wall thickness were determined. It was found that luminal diameter and whole artery thickness increased by age (p < 0.05). In addition, the tunica media was the thickest layer, then tunica intima and at last tunica adventitia (p < 0.05). The muscularity of the right brachiocephalic artery was more than that of the left one (p < 0.05). Histomorphometric study of brachiocephalic arteries of Japanese quails showed that increasing of age causes increase of internal and external diameters of the artery and this increase in females was more than males.

[Vascular aging, arterial hypertension and physical activity].

PubMed

Schmidt-Trucksäss, A; Weisser, B

2011-11-01

The present review delineates the significance of intima-media-thickness, arterial stiffness and endothelial function for vascular aging. There is profound evidence for an increase in intima-media-thickness and vascular stiffness not only during healthy aging but induced also by cardiovascular risk factors. There is a central role of arterial hypertension for this progression in both structural factors. In addition, both parameters are strongly associated with cardiovascular risk. Endothelial function measured as postischemic flow-mediated vasodilatation is a functional parameter which is decreased both in healthy aging and by cardiovascular risk factors. Physical activity modifies the influence of aging and risk factors on endothelial function. A positive influence of endurance exercise on vascular stiffness and endothelial function has been demonstrated in numerous studies. In long-term studies, regular physical activity has been shown to reduce the progression of intima-media-thickness. Thus, arterial hypertension accelerates vascular aging, while physical activity has a positive influence on a variety of vascular parameters associated with vascular aging. © Georg Thieme Verlag KG Stuttgart · New York.

Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation

PubMed Central

2011-01-01

Active myofascial trigger points are one of the major peripheral pain generators for regional and generalized musculoskeletal pain conditions. Myofascial trigger points are also the targets for acupuncture and/or dry needling therapies. Recent evidence in the understanding of the pathophysiology of myofascial trigger points supports The Integrated Hypothesis for the trigger point formation; however unanswered questions remain. Current evidence shows that spontaneous electrical activity at myofascial trigger point originates from the extrafusal motor endplate. The spontaneous electrical activity represents focal muscle fiber contraction and/or muscle cramp potentials depending on trigger point sensitivity. Local pain and tenderness at myofascial trigger points are largely due to nociceptor sensitization with a lesser contribution from non-nociceptor sensitization. Nociceptor and non-nociceptor sensitization at myofascial trigger points may be part of the process of muscle ischemia associated with sustained focal muscle contraction and/or muscle cramps. Referred pain is dependent on the sensitivity of myofascial trigger points. Active myofascial trigger points may play an important role in the transition from localized pain to generalized pain conditions via the enhanced central sensitization, decreased descending inhibition and dysfunctional motor control strategy. PMID:21439050

Long-range traveling waves of activity triggered by local dichoptic stimulation in V1 of behaving monkeys

PubMed Central

Yang, Zhiyong; Heeger, David J.; Blake, Randolph

2014-01-01

Traveling waves of cortical activity, in which local stimulation triggers lateral spread of activity to distal locations, have been hypothesized to play an important role in cortical function. However, there is conflicting physiological evidence for the existence of spreading traveling waves of neural activity triggered locally. Dichoptic stimulation, in which the two eyes view dissimilar monocular patterns, can lead to dynamic wave-like fluctuations in visual perception and therefore, provides a promising means for identifying and studying cortical traveling waves. Here, we used voltage-sensitive dye imaging to test for the existence of traveling waves of activity in the primary visual cortex of awake, fixating monkeys viewing dichoptic stimuli. We find clear traveling waves that are initiated by brief, localized contrast increments in one of the monocular patterns and then, propagate at speeds of ∼30 mm/s. These results demonstrate that under an appropriate visual context, circuitry in visual cortex in alert animals is capable of supporting long-range traveling waves triggered by local stimulation. PMID:25343785

Association between hyperhomocysteinemia and metabolic syndrome with early carotid artery atherosclerosis: A cross-sectional study in middle-aged Chinese population.

PubMed

Liu, Chengguo; Sun, Xiaohui; Lin, Hanli; Zheng, Ruizhi; Ruan, Liansheng; Sun, Zhanhang; Zhu, Yimin

2018-03-21

Homocysteine is a modifiable, independent risk factor for cardiovascular disease. The association between hyperhomocysteinemia and metabolic syndrome with the presence of early carotid artery atherosclerosis remains unknown in middle-aged Chinese adults. Chinese adults (n = 1607) of Han ethnicity, age 35 to 65 y, and living in their communities >2 y were surveyed. Hyperhomocysteinemia was defined as homocysteine concentrations >15 µmol/L. Carotid intima-media thickness and carotid plaque were examined by ultrasonography. All participants were classified into four groups by hyperhomocysteinemia and metabolic syndrome status. Participants with both hyperhomocysteinemia and metabolic syndrome had the highest levels of waist circumference and systolic blood pressure compared with the three other groups. The highest proportion of increased carotid intima-media thickness (61.3%) was in the subgroup of both hyperhomocysteinemia and metabolic syndrome. After adjustments for the covariates, the risk of increased carotid intima-media thickness was only significantly higher in the group with metabolic syndrome but without hyperhomocysteinemia (odds ratio: 1.47; 95% confidence interval, 1.13-1.93) compared with people without hyperhomocysteinemia and metabolic syndrome. Furthermore, statistically significant variances of prevalence of plaque among the four subgroups were not discovered. Our study demonstrated that metabolic syndrome had a strong effect on carotid intima-media thickness However, the increased homocysteine levels were not significantly associated with early carotid artery atherosclerosis in middle-aged Chinese people. Copyright © 2018 Elsevier Inc. All rights reserved.

An Automatic Method for Measurements of Arterial Intima-Media Thickness Using Ultrasonic B-Mode Data

NASA Astrophysics Data System (ADS)

Cinthio, Magnus; Ahlgren, Åsa Rydén; Jansson, Tomas; Nilsson, Tobias; Lindström, Kjell; Persson, Hans W.

We have previously developed algorithms that use B-mode cineloops for simultaneous measurements of arterial diameter change and longitudinal movement of the arterial wall. In this study the lumen diameter algorithm was extended to also measure arterial intima-media thickness of the far wall. To optimize the algorithm the influence of the lateral width of the region-of-interest (1 pixel, 0.1 mm, 0.5 mm, 1 mm, 2.5 mm and 5 mm) was evaluated. The algorithm estimated intima-media thickness at diastole automatically by measuring the distance between the two positions where the laterally averaged B-mode intensity envelope crosses a threshold value relative to the maximum amplitudes of the intimal and adventitial echoes, respectively. The sub-pixel resolution is achieved by solving the equation of a straight line between the two samples on either side of the threshold value. The measurements were performed on 20 healthy normotensive volunteers (age 25-57 years) on the common carotid artery 2-3 cm proximal to the bifurcation. For the 2.5-mm width, which was considered the best, the intima-media thickness was mean 646 μm (SD 66) for men and 613 μm (SD 68) for women. The systematic difference was -5 μm and the random difference was 31 μm. The CV was 4.9%. The study indicates that the reproducibility is sufficient for in vivo studies when the width of the region-of-interest is 1.0 mm or wider.

Evaluation of carotid intima-media thickness and carotid arterial stiffness in children with adenotonsillar hypertrophy.

PubMed

Çiftel, Murat; Demir, Berrin; Kozan, Günay; Yılmaz, Osman; Kahveci, Hasan; Kılıç, Ömer

2016-02-01

Adenotonsillar hypertrophy can produce cardiopulmonary disease in children. However, it is unclear whether adenotonsillar hypertrophy causes atherosclerosis. This study evaluated carotid intimamedia thickness and carotid arterial stiffness in children with adenotonsillar hypertrophy. The study included 40 children with adenotonsillar hypertrophy (age: 5-10 years) and 36 healthy children with similar age and body mass index. Systolic blood pressure, diastolic blood pressure, and pulse pressure were measured in all subjects. Carotid intima-media thickness, carotid arterial systolic diameter, and carotid arterial diastolic diameter were measured using a high-resolution ultrasound device. Based on these measurements, carotid arterial strain, carotid artery distensibility, beta stiffness index, and elasticity modulus were calculated. Carotid intima-media thickness was greater in children with adenotonsillar hypertrophy (0.36±0.05 mm vs. 0.34±0.04 mm, P=0.02) compared to healthy controls. Beta stiffness index (3.01±1.22 vs. 2.98±0.98, P=0.85), elasticity modulus (231.39±99.23 vs. 226.46±83.20, P=0.88), carotid arterial strain (0.17±0.06 vs. 0.17±0.04, P=0.95), and carotid artery distensibility (13.14±3.88 vs. 12.92±3.84, P=0.75) were similar between children with adenotonsillar hypertrophy and the healthy controls. The present study revealed increased carotid intima-media thickness in children with adenotonsillar hypertrophy. The risk of subclinical atherosclerosis may be higher in children with adenotonsillar hypertrophy.

Evaluation of intima media thickness of carotid arteries in 40-60 years old persons with type d personality and its comparison with normal ones.

PubMed

Khorvash, Fariborz; Rahimi, Marzieh; Bagherian-Sararoudi, Reza; Mousavi, Sayed Ali; Ebneshahidi, Alireza; Amirpour, Afshin; Mirabdollahi, Mansoureh Alsadat

2013-05-01

In some studies, the involvement of dangerous psychological and behavioral factors in etiology and physiotherapy of vascular disturbances have been shown. In other studies, the relationship between the personality type and increase in cardiovascular disease has been demonstrated. The type D personality is defined as having two characteristics of negative affect and social inhibition. It is thought that individuals with type D personality are at increased risk of carotid artery intima-media thickening which predisposes them to vascular disease that is one of the most important factors for the stroke. In this study, we try to determine whether type D personality is a contributing factor to an increase in the intima-media of the carotid artery. This study was done in 2012 in the teaching hospital of Alzahra in Isfahan Iran. This is a case/control study which is done at Alzahra hospital in Isfahan in 2011-12. The statistical population in this study is composed of individuals who do not have any risk factors for stroke and are randomly selected among the hospital staff or the patient's family members who accompanied the patient at the hospital. They filled out a questioner that would assist in detecting type D personality. A carotid Doppler ultrasound that measures the intima-media thickness in the selected individuals was performed. The information obtained from the study was evaluated by Statistical Product and Service Solutions (SPSS) software and the intima-media thicknesses were compared in two groups of patients. The average thickness of intima media in two groups, consist of placebo and patients, was 0.739 ± 0.12 and 0.759 ± 0.14 millimeter, respectively. There was no meaningful difference between the two groups based on t-test values (P = 0.19). It is important to note that based on the results, 22.9% of placebos and 48.6% of individuals with type D personality presented with abnormal thickness. The difference between the two groups were meaningful based on Chi-Squared test (P = 0.001). We conclude that type D personality increases the risk of cardiovascular diseases specially the stroke and myocardial infarction due to the higher prevalence of hormonal imbalances leading to arterial vasospasm and atherosclerotic disease. As a result, it is necessary to evaluate and treat these patients due to increased risk of atherosclerotic diseases, stoke, and myocardial infarction.

Event-triggered decentralized adaptive fault-tolerant control of uncertain interconnected nonlinear systems with actuator failures.

PubMed

Choi, Yun Ho; Yoo, Sung Jin

2018-06-01

This paper investigates the event-triggered decentralized adaptive tracking problem of a class of uncertain interconnected nonlinear systems with unexpected actuator failures. It is assumed that local control signals are transmitted to local actuators with time-varying faults whenever predefined conditions for triggering events are satisfied. Compared with the existing control-input-based event-triggering strategy for adaptive control of uncertain nonlinear systems, the aim of this paper is to propose a tracking-error-based event-triggering strategy in the decentralized adaptive fault-tolerant tracking framework. The proposed approach can relax drastic changes in control inputs caused by actuator faults in the existing triggering strategy. The stability of the proposed event-triggering control system is analyzed in the Lyapunov sense. Finally, simulation comparisons of the proposed and existing approaches are provided to show the effectiveness of the proposed theoretical result in the presence of actuator faults. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Electrical Burns and Late Spontaneous Artery Ruptures: About Three Cases.

PubMed

Reinbold, C; Serror, K; Mimoun, M; Chaouat, M; Marco, O; Boccara, D

2018-05-15

Electrical burns are responsible for arterial and venous thrombosis, as well as weakening of the arteries. Immediate or delayed arterial occlusions, secondary to the aggression of the intima, or aneurysms, secondary to the aggression of the media, sometimes lead to artery ruptures without any warning signs. Such ruptures may trigger a hemorrhagic shock whose period of onset is variable and unpredictable. We are presenting here three cases treated in our department for electrical burns, whose complications were marked by hemorrhagic shock, secondary to late artery ruptures, sometimes occurring several months following the event. These case reports required performance of emergency hemostasis in order to control sudden bleeding, with first approach being placement of a tourniquet at the base of the limb and/or a compression point. Through these cases, we thought it is crucial to closely monitor for a few weeks all patients who were victims of electrical injury, even more so if it was associated with a compartment syndrome of one or more limbs and high rhabdomyolysis, which seem to be predictive factors of late artery ruptures in our case reports.

Lipoprotein(a) and HIV: Allele-Specific Apolipoprotein(a) Levels Predict Carotid Intima-Media Thickness in HIV-Infected Young Women in the Women's Interagency HIV Study.

PubMed

Enkhmaa, Byambaa; Anuurad, Erdembileg; Zhang, Wei; Li, Chin-Shang; Kaplan, Robert; Lazar, Jason; Merenstein, Dan; Karim, Roksana; Aouizerat, Brad; Cohen, Mardge; Butler, Kenneth; Pahwa, Savita; Ofotokun, Igho; Adimora, Adaora A; Golub, Elizabeth; Berglund, Lars

2017-05-01

In the general population, lipoprotein(a) [Lp(a)] has been established as an independent causal risk factor for cardiovascular disease. Lp(a) levels are to a major extent regulated by a size polymorphism in the apolipoprotein(a) [apo(a)] gene. The roles of Lp(a)/apo(a) in human immunodeficiency virus (HIV)-related elevated cardiovascular disease risk remain unclear. The associations between total plasma Lp(a) level, allele-specific apo(a) level, an Lp(a) level carried by individual apo(a) alleles, and common carotid artery intima-media thickness were assessed in 150 HIV-infected and 100 HIV-uninfected women in the WIHS (Women's Interagency HIV Study). Linear regression analyses with and without adjustments were used. The cohort was young (mean age, ≈31 years), with the majority being Blacks (≈70%). The prevalence of a small size apo(a) (≤22 Kringle repeats) or a high Lp(a) level (≥30 mg/dL) was similar by HIV status. Total plasma Lp(a) level ( P =0.029) and allele-specific apo(a) level carried by the smaller apo(a) sizes ( P =0.022) were significantly associated with carotid artery intima-media thickness in the HIV-infected women only. After accounting for confounders (age, race, smoking, body mass index, blood pressure, hepatitis C virus coinfection, menopause, plasma lipids, treatment status, CD4 + T cell count, and HIV/RNA viral load), the association remained significant for both Lp(a) ( P =0.035) and allele-specific apo(a) level carried by the smaller apo(a) sizes ( P =0.010) in the HIV-infected women. Notably, none of the other lipids/lipoproteins was associated with carotid artery intima-media thickness. Lp(a) and allele-specific apo(a) levels predict carotid artery intima-media thickness in HIV-infected young women. Further research is needed to identify underlying mechanisms of an increased Lp(a) atherogenicity in HIV infection. © 2017 American Heart Association, Inc.

Carotid intima-media thickness and elastic properties of aortas in normotensive children of hypertensive parents.

PubMed

Yildirim, Ali; Kosger, Pelin; Ozdemir, Gokmen; Sahin, Fezan Mutlu; Ucar, Birsen; Kilic, Zubeyir

2015-09-01

A significant correlation between hypertension history and high blood pressure has been observed with regard to age, race and gender. Investigating carotid intima-media thickness and aortic stiffness prior to the development of hypertension in children of hypertensive parents enabled us to evaluate these patients for subclinical atherosclerosis. We compared carotid intima-media thickness, aortic strain, distensibility, stiffness indices and elastic modulus in 67 normotensive children whose parents had a diagnosis of essential hypertension and 39 normotensive children with no parental history of hypertension. Although there were no significant differences between the two groups in terms of systolic blood pressure, diastolic blood pressure, average blood pressure and pulse pressure (P>0.05), systolic blood pressures were higher among patients 15 years and older in the study group. No significant differences were noted between the control and study groups regarding interventricular septal thickness, left-ventricular posterior wall thickness, left-ventricular systolic and diastolic diameter and aortic annulus diameter (P>0.05). The left atrium diameter was larger in the study group compared with that in the control group, mainly because of the values of the 15-year-old and older children (P=0.01). The mean, maximum and minimum values of carotid intima-media thickness were significantly different in the study group compared with the control group among all age groups (P<0.001, P<0.001, P=0.006, respectively). Aortic systolic and diastolic diameters were larger in normotensive children of hypertensive parents compared with the control group (P=0.014, P=0.001, respectively). Although there were no differences between the study and control groups regarding aortic strain, aortic distensibility, elastic modulus and stiffness indices (P>0.05), aortic distensibility was lower, and aortic stiffness indices were higher among children 15 years and older in the study group. An increase in the carotid intima-media thickness in all age groups and a decrease in aortic elastic properties in 15-year-old and older children of hypertensive parents may indicate subclinical atherosclerosis in these apparently healthy children.

Rationale and design of a multicenter randomized controlled study to evaluate the preventive effect of ipragliflozin on carotid atherosclerosis: the PROTECT study.

PubMed

Tanaka, Atsushi; Murohara, Toyoaki; Taguchi, Isao; Eguchi, Kazuo; Suzuki, Makoto; Kitakaze, Masafumi; Sato, Yasunori; Ishizu, Tomoko; Higashi, Yukihito; Yamada, Hirotsugu; Nanasato, Mamoru; Shimabukuro, Michio; Teragawa, Hiroki; Ueda, Shinichiro; Kodera, Satoshi; Matsuhisa, Munehide; Kadokami, Toshiaki; Kario, Kazuomi; Nishio, Yoshihiko; Inoue, Teruo; Maemura, Koji; Oyama, Jun-Ichi; Ohishi, Mitsuru; Sata, Masataka; Tomiyama, Hirofumi; Node, Koichi

2016-09-13

Type 2 diabetes mellitus is associated strongly with an increased risk of micro- and macro-vascular complications, leading to impaired quality of life and shortened life expectancy. In addition to appropriate glycemic control, multi-factorial intervention for a wide range of risk factors, such as hypertension and dyslipidemia, is crucial for management of diabetes. A recent cardiovascular outcome trial in diabetes patients with higher cardiovascular risk demonstrated that a SGLT2 inhibitor markedly reduced mortality, but not macro-vascular events. However, to date there is no clinical evidence regarding the therapeutic effects of SGLT2 inhibitors on arteriosclerosis. The ongoing PROTECT trial was designed to assess whether the SGLT2 inhibitors, ipragliflozin, prevented progression of carotid intima-media thickness in Japanese patients with type 2 diabetes mellitus. A total of 480 participants with type 2 diabetes mellitus with a HbA1c between 6 and 10 % despite receiving diet/exercise therapy and/or standard anti-diabetic agents for at least 3 months, will be randomized systematically (1:1) into either ipragliflozin or control (continuation of conventional therapy) groups. After randomization, ipragliflozin (50-100 mg once daily) will be added on to the background therapy in participants assigned to the ipragliflozin group. The primary endpoint of the study is the change in mean intima-media thickness of the common carotid artery from baseline to 24 months. Images of carotid intima-media thickness will be analyzed at a central core laboratory in a blinded manner. The key secondary endpoints include the change from baseline in other parameters of carotid intima-media thickness, various metabolic parameters, and renal function. Other cardiovascular functional tests are also planned for several sub-studies. The PROTECT study is the first to assess the preventive effect of ipragliflozin on progression of carotid atherosclerosis using carotid intima-media thickness as a surrogate marker. The study has potential to clarify the protective effects of ipragliflozin on atherosclerosis. Trial registration Unique Trial Number, JPRN/UMIN000018440 ( https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000021348 ).

Cardiovascular Risk Factors and Carotid Intima-Media Thickness in a Colombian Population With Psoriasis.

PubMed

Argote, A; Mora-Hernández, O; Milena Aponte, L; Barrera-Chaparro, D I; Muñoz-Ruiz, L M; Giraldo-Mordecay, L; Camargo, D

2017-10-01

Psoriasis is now known to have a clear association with metabolic syndrome and its components. The aim of our study was to determine the prevalence of cardiovascular risk factors (CVRFs) and increased carotid intima-media thickness in psoriasis patients seen in the dermatology department of a quaternary hospital. This was a descriptive cross-sectional study of psoriasis patients aged over 18 years seen in the dermatology department of Hospital de San José in Bogota, Colombia, between March and August, 2015. Directed medical history and physical examination were performed to detect CVRFs, laboratory studies to exclude metabolic syndrome, and ultrasound examination to measure carotid intima-media thickness. Forty patients with psoriasis were included in the study. The prevalence of the distinct CVRFs was 35% for systemic hypertension, 17.5% for dyslipidemia, 17.5% for smoking, and 10% for type 2 diabetes mellitus. A history of acute myocardial infarction was detected in 12.5% of patients. Metabolic syndrome was found in 20 patients (50%), and blood biochemistry revealed dyslipidemia in 32 patients (80%). Based on the Framingham score, the cardiovascular risk was low in 11 patients (31.4%), intermediate in 22 (62.8%), and high in 2 (5.7%). Mean (SD) carotid intima-media thickness was 0.7 (0.12) mm, with thickening observed in 6 patients (15%). This study provides evidence of the high prevalence of CVRFs in psoriasis patients and indicates the need for strict clinical control to monitor cardiovascular risk in this population. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: A population-based study

PubMed Central

2010-01-01

Background Shoulder pain is a common health problem. The purpose of this study was to assess the associations of lifestyle factors, metabolic factors and carotid intima-media thickness with shoulder pain and chronic (> 3 months) rotator cuff tendinitis. Methods In this cross-sectional study, the target population consisted of subjects aged 30 years or older participating in a national Finnish Health Survey during 2000-2001. Of the 7,977 eligible subjects, 6,237 (78.2%) participated in a structured interview and clinical examination. Chronic rotator cuff tendinitis was diagnosed clinically. Weight-related factors, C-reactive protein and carotid intima-media thickness were measured. Results The prevalence of shoulder joint pain during the preceding 30 days was 16% and that of chronic rotator cuff tendinitis 2.8%. Smoking, waist circumference and waist-to-hip ratio were related to an increased prevalence of shoulder pain in both genders. Metabolic syndrome, type 2 diabetes mellitus and carotid intima-media thickness were associated with shoulder pain in men, whereas high level of C-reactive protein was associated with shoulder pain in women. Increased waist circumference and type 1 diabetes mellitus were associated with chronic rotator cuff tendinitis in men. Conclusions Our findings showed associations of abdominal obesity, some other metabolic factors and carotid intima-media thickness with shoulder pain. Disturbed glucose metabolism and atherosclerosis may be underlying mechanisms, although not fully supported by the findings of this study. Prospective studies are needed to further investigate the role of lifestyle and metabolic factors in shoulder disorders. PMID:20646281

Effect of rimonabant on carotid intima-media thickness (CIMT) progression in patients with abdominal obesity and metabolic syndrome: the AUDITOR Trial.

PubMed

O'Leary, Daniel H; Reuwer, Anne Q; Nissen, Steven E; Després, Jean-Pierre; Deanfield, John E; Brown, Michael W; Zhou, Rong; Zabbatino, Salvatore M; Job, Bernard; Kastelein, John J P; Visseren, Frank L J

2011-07-01

The aim of this trial was to determine whether obese patients benefit from treatment with rimonabant in terms of progression of carotid atherosclerosis. Rimonabant, a selective cannabinoid-1 receptor blocker, reduces body weight and improves cardiometabolic risk factors in patients who are obese. A prospective, double-blind, placebo-controlled trial (Atherosclerosis Underlying Development assessed by Intima-media Thickness in patients On Rimonabant (AUDITOR)) randomised 661 patients with abdominal obesity and metabolic syndrome to rimonabant or placebo for 30 months of treatment. The absolute change in the average value for six segments of far wall carotid intima-media thickness from baseline to month 30 was 0.010 ± 0.095 mm in the rimonabant group and 0.012 ± 0.091 mm in the placebo group (p=0.67). The annualised change was an increase of 0.005 ± 0.042 mm for the rimonabant-treated group and 0.007 ± 0.043 mm for the placebo-treated group (p=0.45). There was no difference in atherosclerosis progression between patients receiving rimonabant for 30 months and those receiving placebo for the primary efficacy measure (absolute change in carotid intima-media thickness). These findings are consistent with a similar study using coronary intravascular ultrasound and another study evaluating the occurrence of cardiovascular events. Our findings suggest that a 5% loss of body weight over a 30-month period with rimonabant is insufficient to modify atherosclerosis progression in the carotid artery in obese patients with metabolic syndrome. Clinical trial registration information clinicaltrials.gov Identifier: NCT00228176.

Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: a population-based study.

PubMed

Rechardt, Martti; Shiri, Rahman; Karppinen, Jaro; Jula, Antti; Heliövaara, Markku; Viikari-Juntura, Eira

2010-07-20

Shoulder pain is a common health problem. The purpose of this study was to assess the associations of lifestyle factors, metabolic factors and carotid intima-media thickness with shoulder pain and chronic (> 3 months) rotator cuff tendinitis. In this cross-sectional study, the target population consisted of subjects aged 30 years or older participating in a national Finnish Health Survey during 2000-2001. Of the 7,977 eligible subjects, 6,237 (78.2%) participated in a structured interview and clinical examination. Chronic rotator cuff tendinitis was diagnosed clinically. Weight-related factors, C-reactive protein and carotid intima-media thickness were measured. The prevalence of shoulder joint pain during the preceding 30 days was 16% and that of chronic rotator cuff tendinitis 2.8%. Smoking, waist circumference and waist-to-hip ratio were related to an increased prevalence of shoulder pain in both genders. Metabolic syndrome, type 2 diabetes mellitus and carotid intima-media thickness were associated with shoulder pain in men, whereas high level of C-reactive protein was associated with shoulder pain in women. Increased waist circumference and type 1 diabetes mellitus were associated with chronic rotator cuff tendinitis in men. Our findings showed associations of abdominal obesity, some other metabolic factors and carotid intima-media thickness with shoulder pain. Disturbed glucose metabolism and atherosclerosis may be underlying mechanisms, although not fully supported by the findings of this study. Prospective studies are needed to further investigate the role of lifestyle and metabolic factors in shoulder disorders.

Experience With Intravascular Ultrasound Imaging Of Human Atherosclerotic Arteries

NASA Astrophysics Data System (ADS)

Mallery, John A.; Gessert, James M.; Maciel, Mario; Tobis, John M.; Griffith, James M.; Berns, Michael W.; Henry, Walter L.

1989-08-01

Normal human arteries have a well-defined structure on intravascular images. The intima appears very thin and is most likely represented by a bright reflection arising from the internal elastic lamina. The smooth muscle tunica media is echo-lucent on the ultrasound image and appears as a dark band separating the intima from the adventitia. The adventitia is a brightly reflective layer of variable thickness. The thickness of the intima, and therefore of the atherosclerotic plaque can be accurately measured from the ultrasound images and correlates well with histology. Calcification within the wall of arteries is seen as bright echo reflection with shadowing of the peripheral wall. Fibrotic regions are highly reflective but do not shadow. Necrotic liquid regions within advanced atherosclerotic plaques are seen on ultrasound images as large lucent zones surrounded by echogenic tissue. Imaging can be performed before and after interventional procedures, such as laser angioplasty, balloon angioplasty and atherectomy. Intravascular ultrasound appears to provide an imaging modality for identifying the histologic characteristics of diseased arteries and for quantifying plaque thickness. It might be possible to perform such quantification to evaluate the results of interventional procedures.

[Association of age, inflammatory markers and subclinical atherosclerosis in subjects free from cardiovascular disease].

PubMed

Páramo, José A; Orbe, Josune; Beloqui, Oscar; Colina, Inmaculada; Benito, Alberto; Rodríguez, José A; Díez, Javier

2008-09-27

We assessed whether an independent association between inflammatory markers and age-related subclinical atherosclerosis could be found in subjects free from cardiovascular disease. Metabolic parameters, inflammatory and endothelial markers, such as high-sensitivity C-reactive protein, interleukin-6, fibrinogen and von Willebrand factor, as well as the carotid intima-media thickness were assessed in 890 asymptomatic subjects (mean age: 55 years; range: 20-80 years; 80% men) with cardiovascular risk factors. Subjects in the upper quartile (age 61-80 years) showed a significant increase of traditional risk factors, particularly arterial pressure and glucose levels (p < 0.01) as compared with lower quartiles. We also found a significant increase in the levels on inflammatory and endothelial markers (p < 0.001) and intima-media thickness (p < 0.001) in older adults. In the multivarate analysis, after adjustment for cardiovascular risk factors, intima-media thickness was independently associated with inflammation and endothelial dysfunction in older adults (p < 0.01). Besides age, systemic inflammation and vascular damage are associated with subclinical atherosclerosis in asymptomatic subjects. The age-related inflammatory profile may predispose to cardiovascular complications.

[Reddish discoloration of the vascular intima in charred bodies].

PubMed

Stiller, Dankwart; Lang, Juliane; Kleiber, Manfred; Rüdiger Lessig; Bohnert, Michael

2015-01-01

During the autopsy of fire victims, one often sees intensive reddening of the inner vascular layers resembling changes due to putrefaction. To determine the frequency of this phenomenon and the circumstances under which it occurs, in particular the presence of putrescence, signs of vitality and the extent of destruction by the fire, the fire fatalities autopsied at the Institutes of Legal Medicine in Freiburg, Halle and Würzburg were analyzed. In the concrete study, 259 fire deaths were investigated retrospectively and 21 prospectively. The study material included 191 males and 68 females aged 0 to 93 years. Vital exposure to the fire was found in 70%, perimortal exposure in 23 % and postmortem exposure in 7% of the cases. Red discoloration of the intima of the central vessels was seen in 106 victims (41%). This finding is most likely caused by postmortem heat-induced hemolysis, which occurs when the temperature in the body rises above 52 °C due to the effect of external heat. Therefore, a reddish discoloration of the intima cannot be regarded as sign of vitality.

Towards a Systematic Search for Triggered Seismic Events in the USA

NASA Astrophysics Data System (ADS)

Tang, V.; Chao, K.; Van der Lee, S.

2017-12-01

Dynamic triggering of small earthquakes and tectonic tremor by small stress variations associated with passing surface waves from large-magnitude teleseismic earthquakes have been observed in seismically active regions in the western US. Local stress variations as small as 5 10 kPa can suffice to advance slip on local faults. Observations of such triggered events share certain distinct characteristics. With an eye towards an eventual application of machine learning, we began a systematic search for dynamically triggered seismic events in the USA that have these characteristics. Such a systematic survey has the potential to help us to better understand the fundamental process of dynamic triggering and hazards implied by it. Using visual inspection on top of timing and frequency based selection criteria for these seismic phenomena, our search yielded numerous false positives, indicating the challenge posed by moving from ad-hoc observations of dynamic triggering to a systematic search that also includes a catalog of non-triggering, even when sufficient stress variations are supplied. Our search includes a dozen large earthquakes that occurred during the tenure of USArray. One of these earthquakes (11 April 2012 Mw8.6 Sumatra), for example, was observed by USArray-TA stations in the Midwest and other station networks (such as PB and UW), and yielded candidate-triggered events at 413 stations. We kept 79 of these observations after closer visual inspection of the observed events suggested distinct P and S arrivals from a local earthquake, or a tremor modulation with the same period as the surface wave, among other criteria. We confirmed triggered seismic events in 63 stations along the western plate boundary where triggered events have previously been observed. We also newly found triggered tremor sources in eastern Oregon and Yellowstone, and candidate-triggered earthquake sources in New Mexico and Minnesota. Learning whether 14 of remaining candidates are confirmed as triggered events or not will provide constraints on the state of intraplate stress in the USA. Learning what it takes to discriminate between triggered events and false positives will be important for future monitoring practices.

Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

NASA Astrophysics Data System (ADS)

Lunsford, R.; Sun, Z.; Maingi, R.; Hu, J. S.; Mansfield, D.; Xu, W.; Zuo, G. Z.; Diallo, A.; Osborne, T.; Tritz, K.; Canik, J.; Huang, M.; Meng, X. C.; Gong, X. Z.; Wan, B. N.; Li, J. G.; the EAST Team

2018-03-01

The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1 mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter  >600 microns are successful in triggering ELMs more than 95% of the time. It was also demonstrated that below 600 microns the triggering efficiency decreased roughly with granule size. Granules were radially injected from the outer midplane with velocities ~80 m s-1 into EAST upper single null discharges with an ITER like tungsten monoblock divertor. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. For those granules of sufficient size, ELM triggering was a prompt response to granule injection. By simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined.

The role of disturbed blood flow in the development of pulmonary arterial hypertension: lessons from preclinical animal models.

PubMed

Dickinson, Michael G; Bartelds, Beatrijs; Borgdorff, Marinus A J; Berger, Rolf M F

2013-07-01

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vasoproliferative disorder characterized by the development of unique neointimal lesions, including concentric laminar intima fibrosis and plexiform lesions. Although the histomorphology of neointimal lesions is well described, the pathogenesis of PAH and neointimal development is largely unknown. After three decades of PAH pathobiology research the focus has shifted from vasoconstriction towards a mechanism of cancer-like angioproliferation. In this concept the role of disturbed blood flow is seen as an important trigger in the development of vascular remodeling. For instance, in PAH associated with congenital heart disease, increased pulmonary blood flow (i.e., systemic-to-pulmonary shunt) is an essential trigger for the occurrence of neointimal lesions and PAH development. Still, questions remain about the exact role of these blood flow characteristics in disease progression. PAH animal models are important for obtaining insight in new pathobiological processes and therapeutical targets. However, as for any preclinical model the pathophysiological mechanism and clinical course has to be comparable to the human disease that it mimics. This means that animal models mimicking human PAH ideally are characterized by: a hit recognized in human disease (e.g., altered pulmonary blood flow), specific vascular remodeling resembling human neointimal lesions, and disease progression that leads to right ventriclular dysfunction and death. A review that underlines the current knowledge of PAH due to disturbed flow is still lacking. In this review we will summarize the current knowledge obtained from PAH animal models associated with disturbed pulmonary blood flow and address questions for future treatment strategies for PAH.

Rainfall-triggered shallow landslides at catchment scale: Threshold mechanics-based modeling for abruptness and localization

NASA Astrophysics Data System (ADS)

von Ruette, J.; Lehmann, P.; Or, D.

2013-10-01

Rainfall-induced shallow landslides may occur abruptly without distinct precursors and could span a wide range of soil mass released during a triggering event. We present a rainfall-induced landslide-triggering model for steep catchments with surfaces represented as an assembly of hydrologically and mechanically interconnected soil columns. The abruptness of failure was captured by defining local strength thresholds for mechanical bonds linking soil and bedrock and adjacent columns, whereby a failure of a single bond may initiate a chain reaction of subsequent failures, culminating in local mass release (a landslide). The catchment-scale hydromechanical landslide-triggering model (CHLT) was applied to results from two event-based landslide inventories triggered by two rainfall events in 2002 and 2005 in two nearby catchments located in the Prealps in Switzerland. Rainfall radar data, surface elevation and vegetation maps, and a soil production model for soil depth distribution were used for hydromechanical modeling of failure patterns for the two rainfall events at spatial and temporal resolutions of 2.5 m and 0.02 h, respectively. The CHLT model enabled systematic evaluation of the effects of soil type, mechanical reinforcement (soil cohesion and lateral root strength), and initial soil water content on landslide characteristics. We compared various landslide metrics and spatial distribution of simulated landslides in subcatchments with observed inventory data. Model parameters were optimized for the short but intense rainfall event in 2002, and the calibrated model was then applied for the 2005 rainfall, yielding reasonable predictions of landslide events and volumes and statistically reproducing localized landslide patterns similar to inventory data. The model provides a means for identifying local hot spots and offers insights into the dynamics of locally resolved landslide hazards in mountainous regions.

Dynamic triggering

USGS Publications Warehouse

Hill, David P.; Prejean, Stephanie; Schubert, Gerald

2015-01-01

Dynamic stresses propagating as seismic waves from large earthquakes trigger a spectrum of responses at global distances. In addition to locally triggered earthquakes in a variety of tectonic environments, dynamic stresses trigger tectonic (nonvolcanic) tremor in the brittle–plastic transition zone along major plate-boundary faults, activity changes in hydrothermal and volcanic systems, and, in hydrologic domains, changes in spring discharge, water well levels, soil liquefaction, and the eruption of mud volcanoes. Surface waves with periods of 15–200 s are the most effective triggering agents; body-wave trigger is less frequent. Triggering dynamic stresses can be < 1 kPa.

EMIC triggered chorus emissions in Cluster data

NASA Astrophysics Data System (ADS)

Grison, B.; SantolíK, O.; Cornilleau-Wehrlin, N.; Masson, A.; Engebretson, M. J.; Pickett, J. S.; Omura, Y.; Robert, P.; Nomura, R.

2013-03-01

Electromagnetic ion cyclotron (EMIC) triggered chorus emissions have recently been a subject of several experimental, theoretical and simulation case studies, noting their similarities with whistler-mode chorus. We perform a survey of 8 years of Cluster data in order to increase the database of EMIC triggered emissions. The results of this is that EMIC triggered emissions have been unambiguously observed for only three different days. These three events are studied in detail. All cases have been observed at the plasmapause between 22 and 24 magnetic local time (MLT) and between - 15° and 15° magnetic latitude (λm). Triggered emissions are also observed for the first time below the local He+ gyrofrequency (fHe+). The number of events is too low to produce statistical results, nevertheless we point out a variety of common properties of those waves. The rising tones have a high level of coherence and the waves propagate away from the equatorial region. The propagation angle and degree of polarization are related to the distance from the equator, whereas the slope and the frequency extent vary from one event to the other. From the various spacecraft separations, we determine that the triggering process is a localized phenomenon in space and time. However, we are unable to determine the occurrence rates of these waves. Small frequency extent rising tones are more common than large ones. The newly reported EMIC triggered events are generally observed during periods of large AE index values and in time periods close to solar maximum.

The Effect of the Ketogenic Diet on the Vascular Structure and Functions in Children With Intractable Epilepsy.

PubMed

Özdemir, Rahmi; Güzel, Orkide; Küçük, Mehmet; Karadeniz, Cem; Katipoglu, Nagehan; Yılmaz, Ünsal; Yılmazer, Murat Muhtar; Meşe, Timur

2016-03-01

We aimed to determine the midterm effect of a ketogenic diet on serum lipid levels, carotid intima-media thickness, and the elastic properties of the carotid artery and the aorta in patients with intractable epilepsy. A total of 52 children aged between 12 months and 18 years with intractable epilepsy who started the ketogenic diet from September 2014 to September 2015 were included into this prospective study. Carotid intima-media thickness and the elastic properties of the carotid artery and the aorta were assessed by echocardiography in all cases before beginning of the ketogenic diet and after at least 12 months on the ketogenic diet. Twenty-one patients at the third month and 25 patients at the first year of the ketogenic diet were seizure free. A reduction of greater than 90% in the seizure frequency was achieved in three patients at the sixth month and in five patients at the first year of the treatment. The serum levels of total cholesterol, low-density lipoprotein, and triglyceride were increased significantly at a median of 12.6 months (range: 12 to 13.5 months) of the ketogenic diet treatment, whereas serum levels of high-density lipoprotein did not change. Carotid intima-media thickness, aortic and carotid strain, the stiffness index, distensibility, and elastic modulus did not change after 12 months of the ketogenic diet therapy. Olive oil-based ketogenic diet appears to have no disturbing effect on the carotid intima-media thickness and the elastic properties of the aorta and the carotid artery in epileptic children, although it may be associated with increased concentrations of serum lipids. Copyright © 2016 Elsevier Inc. All rights reserved.

Menopausal Hot Flashes and Carotid Intima Media Thickness Among Midlife Women.

PubMed

Thurston, Rebecca C; Chang, Yuefang; Barinas-Mitchell, Emma; Jennings, J Richard; Landsittel, Doug P; Santoro, Nanette; von Känel, Roland; Matthews, Karen A

2016-12-01

There has been a longstanding interest in the role of menopause and its correlates in the development of cardiovascular disease (CVD) in women. Menopausal hot flashes are experienced by most midlife women; emerging data link hot flashes to CVD risk indicators. We tested whether hot flashes, measured via state-of-the-art physiologic methods, were associated with greater subclinical atherosclerosis as assessed by carotid ultrasound. We considered the role of CVD risk factors and estradiol concentrations in these associations. A total of 295 nonsmoking women free of clinical CVD underwent ambulatory physiologic hot flash assessments; a blood draw; and carotid ultrasound measurement of intima media thickness and plaque. Associations between hot flashes and subclinical atherosclerosis were tested in regression models controlling for CVD risk factors and estradiol. More frequent physiologic hot flashes were associated with higher carotid intima media thickness (for each additional hot flash: β [SE]=0.004 [0.001]; P=0.0001; reported hot flash: β [SE]=0.008 [0.002]; P=0.002, multivariable) and plaque (eg, for each additional hot flash, odds ratio [95% confidence interval] plaque index ≥2=1.07 [1.003-1.14]; P=0.04, relative to no plaque, multivariable] among women reporting daily hot flashes; associations were not accounted for by CVD risk factors or by estradiol. Among women reporting hot flashes, hot flashes accounted for more variance in intima media thickness than most CVD risk factors. Among women reporting daily hot flashes, frequent hot flashes may provide information about a woman's vascular status beyond standard CVD risk factors and estradiol. Frequent hot flashes may mark a vulnerable vascular phenotype among midlife women. © 2016 American Heart Association, Inc.

Automated carotid artery intima layer regional segmentation.

PubMed

Meiburger, Kristen M; Molinari, Filippo; Acharya, U Rajendra; Saba, Luca; Rodrigues, Paulo; Liboni, William; Nicolaides, Andrew; Suri, Jasjit S

2011-07-07

Evaluation of the carotid artery wall is essential for the assessment of a patient's cardiovascular risk or for the diagnosis of cardiovascular pathologies. This paper presents a new, completely user-independent algorithm called carotid artery intima layer regional segmentation (CAILRS, a class of AtheroEdge™ systems), which automatically segments the intima layer of the far wall of the carotid ultrasound artery based on mean shift classification applied to the far wall. Further, the system extracts the lumen-intima and media-adventitia borders in the far wall of the carotid artery. Our new system is characterized and validated by comparing CAILRS borders with the manual tracings carried out by experts. The new technique is also benchmarked with a semi-automatic technique based on a first-order absolute moment edge operator (FOAM) and compared to our previous edge-based automated methods such as CALEX (Molinari et al 2010 J. Ultrasound Med. 29 399-418, 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CULEX (Delsanto et al 2007 IEEE Trans. Instrum. Meas. 56 1265-74, Molinari et al 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CALSFOAM (Molinari et al Int. Angiol. (at press)), and CAUDLES-EF (Molinari et al J. Digit. Imaging (at press)). Our multi-institutional database consisted of 300 longitudinal B-mode carotid images. In comparison to semi-automated FOAM, CAILRS showed the IMT bias of -0.035 ± 0.186 mm while FOAM showed -0.016 ± 0.258 mm. Our IMT was slightly underestimated with respect to the ground truth IMT, but showed uniform behavior over the entire database. CAILRS outperformed all the four previous automated methods. The system's figure of merit was 95.6%, which was lower than that of the semi-automated method (98%), but higher than that of the other automated techniques.

Automated carotid artery intima layer regional segmentation

NASA Astrophysics Data System (ADS)

Meiburger, Kristen M.; Molinari, Filippo; Rajendra Acharya, U.; Saba, Luca; Rodrigues, Paulo; Liboni, William; Nicolaides, Andrew; Suri, Jasjit S.

2011-07-01

Evaluation of the carotid artery wall is essential for the assessment of a patient's cardiovascular risk or for the diagnosis of cardiovascular pathologies. This paper presents a new, completely user-independent algorithm called carotid artery intima layer regional segmentation (CAILRS, a class of AtheroEdge™ systems), which automatically segments the intima layer of the far wall of the carotid ultrasound artery based on mean shift classification applied to the far wall. Further, the system extracts the lumen-intima and media-adventitia borders in the far wall of the carotid artery. Our new system is characterized and validated by comparing CAILRS borders with the manual tracings carried out by experts. The new technique is also benchmarked with a semi-automatic technique based on a first-order absolute moment edge operator (FOAM) and compared to our previous edge-based automated methods such as CALEX (Molinari et al 2010 J. Ultrasound Med. 29 399-418, 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CULEX (Delsanto et al 2007 IEEE Trans. Instrum. Meas. 56 1265-74, Molinari et al 2010 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57 1112-24), CALSFOAM (Molinari et al Int. Angiol. (at press)), and CAUDLES-EF (Molinari et al J. Digit. Imaging (at press)). Our multi-institutional database consisted of 300 longitudinal B-mode carotid images. In comparison to semi-automated FOAM, CAILRS showed the IMT bias of -0.035 ± 0.186 mm while FOAM showed -0.016 ± 0.258 mm. Our IMT was slightly underestimated with respect to the ground truth IMT, but showed uniform behavior over the entire database. CAILRS outperformed all the four previous automated methods. The system's figure of merit was 95.6%, which was lower than that of the semi-automated method (98%), but higher than that of the other automated techniques.

Neonatal Arterial Morphology Is Related to Body Size in Abnormal Human Fetal Growth.

PubMed

Olander, Rasmus F W; Sundholm, Johnny K M; Ojala, Tiina H; Andersson, Sture; Sarkola, Taisto

2016-09-01

Restriction in fetal growth is associated with cardiovascular disease in adulthood. It is unclear whether abnormal intrauterine growth influences arterial morphology during the fetal or neonatal stage. The objective was to study the regional arterial morphology with respect to gestational age and abnormal fetal body size. We studied body anthropometrics and arterial morphology and physiology in 174 neonates born between 31 and 42 weeks of gestation, including neonates with birth weights appropriate, small, and large for age, with very high resolution vascular ultrasound (35-55 MHz). In simple linear regressions, parameters of body size (body weight, body surface area, and organ circumference) and gestational age were statistically significantly associated with common carotid, brachial, femoral arterial parameters (lumen diameter [LD], wall layer thickness [intima-media thickness and intima-media-adventitia thickness], and carotid artery wall stress [CAWS]). Male sex was statistically significantly associated with LD and CAWS. In multiple linear regression models, body size, gestational age, and sex explained a large proportion of the arterial variance (R( 2) range, 0.37-0.47 for LD; 0.09-0.35 for intima-media thickness; 0.21-0.41 for intima-media-adventitia thickness; and 0.23 for CAWS; all models P<0.001). Arterial wall layer thickness, LDs, and CAWS were independently and strongly predicted by body size, and no effect of maternal disease was observed when added to the models. Gestational age and male sex were also independently but more weakly associated with arterial LDs and CAWS (P<0.01), but not with arterial wall layers. These results indicate that the intrauterine growth of fetal arterial LD and wall layer thickness are primarily attributed to body growth overall. LD and CAWS show weaker association with gestational age and sex. © 2016 American Heart Association, Inc.

High-dose B vitamin supplementation and progression of subclinical atherosclerosis: a randomized controlled trial.

PubMed

Hodis, Howard N; Mack, Wendy J; Dustin, Laurie; Mahrer, Peter R; Azen, Stanley P; Detrano, Robert; Selhub, Jacob; Alaupovic, Petar; Liu, Chao-ran; Liu, Ci-hua; Hwang, Juliana; Wilcox, Alison G; Selzer, Robert H

2009-03-01

Although plasma total homocysteine (tHcy) levels are associated with cardiovascular disease, it remains unclear whether homocysteine is a cause or a marker of atherosclerotic vascular disease. We determined whether reduction of tHcy levels with B vitamin supplementation reduces subclinical atherosclerosis progression. In this double-blind clinical trial, 506 participants 40 to 89 years of age with an initial tHcy >8.5 micromol/L without diabetes and cardiovascular disease were randomized to high-dose B vitamin supplementation (5 mg folic acid+0.4 mg vitamin B(12)+50 mg vitamin B(6)) or matching placebo for 3.1 years. Subclinical atherosclerosis progression across 3 vascular beds was assessed using high-resolution B-mode ultrasonography to measure carotid artery intima media thickness (primary outcome) and multidetector spiral CT to measure aortic and coronary artery calcium (secondary outcome). Although the overall carotid artery intima media thickness progression rate was lower with B vitamin supplementation than with placebo, statistically significant between-group differences were not found (P=0.31). However, among subjects with baseline tHcy >or=9.1 micromol/L, those randomized to B vitamin supplementation had a statistically significant lower average rate of carotid artery intima media thickness progression compared with placebo (P=0.02); among subjects with a baseline tHcy <9.1 micromol/L, there was no significant treatment effect (probability value for treatment interaction=0.02). B vitamin supplementation had no effect on progression of aortic or coronary artery calcification overall or within subgroups. High-dose B vitamin supplementation significantly reduces progression of early-stage subclinical atherosclerosis (carotid artery intima media thickness) in well-nourished healthy B vitamin "replete" individuals at low risk for cardiovascular disease with a fasting tHcy >or=9.1 micromol/L.

Office and 24-hour heart rate and target organ damage in hypertensive patients

PubMed Central

2012-01-01

Background We investigated the association between heart rate and its variability with the parameters that assess vascular, renal and cardiac target organ damage. Methods A cross-sectional study was performed including a consecutive sample of 360 hypertensive patients without heart rate lowering drugs (aged 56 ± 11 years, 64.2% male). Heart rate (HR) and its standard deviation (HRV) in clinical and 24-hour ambulatory monitoring were evaluated. Renal damage was assessed by glomerular filtration rate and albumin/creatinine ratio; vascular damage by carotid intima-media thickness and ankle/brachial index; and cardiac damage by the Cornell voltage-duration product and left ventricular mass index. Results There was a positive correlation between ambulatory, but not clinical, heart rate and its standard deviation with glomerular filtration rate, and a negative correlation with carotid intima-media thickness, and night/day ratio of systolic and diastolic blood pressure. There was no correlation with albumin/creatinine ratio, ankle/brachial index, Cornell voltage-duration product or left ventricular mass index. In the multiple linear regression analysis, after adjusting for age, the association of glomerular filtration rate and intima-media thickness with ambulatory heart rate and its standard deviation was lost. According to the logistic regression analysis, the predictors of any target organ damage were age (OR = 1.034 and 1.033) and night/day systolic blood pressure ratio (OR = 1.425 and 1.512). Neither 24 HR nor 24 HRV reached statistical significance. Conclusions High ambulatory heart rate and its variability, but not clinical HR, are associated with decreased carotid intima-media thickness and a higher glomerular filtration rate, although this is lost after adjusting for age. Trial Registration ClinicalTrials.gov: NCT01325064 PMID:22439900

Prognostic value of carotid intima-media in the short- and long-term mortality in the Strategy of Registry of Acute Coronary Syndrome (ERICO) study.

PubMed

Meireles, Danilo P; Santos, Itamar S; Alencar, Airlane P; Lotufo, Paulo A; Benseñor, Isabela M; Goulart, Alessandra C

2018-06-10

Atherosclerotic in carotids can determinate a poor prognosis in individuals after acute coronary syndrome (ACS). Thus, we aimed to evaluate mortality associated to carotid intima media thickness (CIMT) in the participants from the Strategy of Registry of Acute Coronary Syndrome (ERICO) study. Carotid intima media thickness was evaluated by B-mode ultrasound for mortality risk assessment in 180 days, 1-3 years. We performed Kaplan-Meier survival curves and Cox logistic regression models to evaluate all-cause, cardiovascular (CVD) and coronary heart disease (CHD) mortality by CIMT tertiles in crude, age and sex- and multivariate models. Among 644 ACS individuals (median age 61-year old), we observed a median CIMT of 0.74 mm. Besides aging, low education, hypertension, diabetes, and dyslipidemia were associated with the 3rd tertile of CIMT values. During 3 years of follow-up, we observed 65 deaths (10.1%), crude case-fatality rates were progressively higher across the CIMT tertiles in all periods, being the highest rates observed in participants with the highest CIMT (3rd tertile) (180-day: 6.6% vs 1-year: 9.0% vs 2-year:12.3% vs 3-year:16.0%, P < .05). In crude analyses, lowest survival rates (all-cause, CVD and CHD, p log-rank values <0.005) and higher hazard ratios of dying for all-cause and CVD (from 1 to 3 years) and for CHD (2 and 3 years) were observed. However, we kept no significant results after adjusting for age. Carotid intima media thickness was mainly influenced by aging. CIMT was not a good predictor of all-cause, CVD or CHD mortality in the ERICO study. © 2018 Wiley Periodicals, Inc.

Micromorphology of Skeletonized and Pedicled Internal Thoracic and Radial Arteries.

PubMed

Mamchur, Sergey; Bokhan, Nikita; Vecherskii, Yuri; Malyshenko, Egor

2015-01-01

The objective of the study was to estimate the internal thoracic arteries (ITA) and radial arteries (RA) micromorphologic features by light microscopy after harvesting them using the skeletonization and pedicled methods in patients undergoing coronary artery bypass grafting. The micromorphologic characteristics of ITA and RA were studied by luminous microscopy in 61 patients undergoing coronary artery bypass grafting. A total of 122 ITA and RA segments harvested during surgery, fixed in formalin, and stained with hematoxiline and eosin were evaluated. The mean intima-media thickness of ITA was 9.2 and 134.7 µm and that of RA was 9.1 and 334.2 µm, respectively. In the distal segment of ITA the media-intima relation was 1.5 times bigger than in the proximal segment. None of ITA specimens contained atherosclerotic plaques or lipid inclusions. Atherosclerotic plaques were found in 3 (5%) RA specimens. Other degenerative changes were detected in 30%-74.2% of the specimens: splitting of internal elastic lamina, reduced tortuosity of the internal elastic lamina, and thickening and detachment of the intima; their incidence was associated with the skeletonization of the vessels. In conclusion, the incidence of ITA and RA degenerative changes varies from 30%-74.2% and its increase is associated with the skeletonization of the vessels, which is statistically significant. The media of the RA is 2.5 times thicker than that of the ITA (P < 0.01). This fact shows that RA has higher spasmogenic potential than that of ITA. The distal segment of the ITA has 1.5 times bigger media-intima relation than the proximal segment. Therefore, in case of enough graft length, it is recommended to avoid the distal segment and cut it off. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of active and passive smoking on the development of cardiovascular disease as assessed by a carotid intima-media thickness examination in patients with type 2 diabetes mellitus.

PubMed

Jiang, Fei; Wang, Jie; Zhang, Rong; Chen, Miao; Peng, Danfeng; Sun, Xue; Yan, Jing; Luo, Yi; Tang, Shanshan; Hu, Cheng; Jia, Weiping

2015-05-01

Carotid intima-media thickness has been widely used as a surrogate end-point for cardiovascular disease, myocardial infarction, and stroke. This study aimed to assess the effects of active and passive smoking exposure on the development of cardiovascular disease in patients with type 2 diabetes mellitus. Seven hundred twenty-two patients with type 2 diabetes mellitus were recruited for the study. A standardized questionnaire on smoking status, pack-years of smoking, and the number of years of smoking cessation was provided to the patients, and their responses were collected for analysis. The carotid intima-media thickness, carotid plaque, and the internal diameter of the common carotid artery were determined by high-resolution B-mode ultrasonography. Compared to non-smokers, passive female smokers had a higher risk of cardiovascular disease (odds ratio = 3.50, 95% confidence interval: 1.29-9.49, P = 0.009); they also had a significantly larger common carotid artery (P = 0.041) and risk of carotid plaque (odds ratio = 2.20, 95% confidence interval: 1.1980-4.0505, P = 0.01). Both active and passive male smokers had a significantly greater carotid intima-media thickness than non-smokers (P = 0.003 and P = 0.005, respectively). Male active smokers had a significantly higher risk of carotid plaque (odds ratio = 2.88, 95% confidence interval: 1.4788-5.6094, P = 0.001). In conclusion, cumulative active and passive smoking exposures are significant risk factors for carotid atherosclerosis in patients with type 2 diabetes mellitus. Our results highlight the importance of endorsing a smoke-free environment for patients with type 2 diabetes mellitus. © 2015 Wiley Publishing Asia Pty Ltd.

Similar degree of intimal hyperplasia in surgically detected stenotic and nonstenotic arteriovenous fistula segments: a preliminary report.

PubMed

Duque, Juan C; Tabbara, Marwan; Martinez, Laisel; Paez, Angela; Selman, Guillermo; Salman, Loay H; Velazquez, Omaida C; Vazquez-Padron, Roberto I

2018-04-01

Intimal hyperplasia has been historically associated with improper venous remodeling and stenosis after creation of an arteriovenous fistula. Recently, however, we showed that intimal hyperplasia by itself does not explain the failure of maturation of 2-stage arteriovenous fistulas. We seek to evaluate whether intimal hyperplasia plays a role in the development of focal stenosis of an arteriovenous fistula. This study compares intimal hyperplasia lesions in stenotic and nearby nonstenotic segments collected from the same arteriovenous fistula. Focal areas of stenosis were detected in the operating room in patients (n= 14) undergoing the second-stage vein transposition procedure. The entire vein was inspected, and areas of stenosis were visually located with the aid of manual palpation and hemodynamic changes in the vein peripheral and central to the narrowing. Stenotic and nonstenotic segments were documented by photography before tissue collection (14 tissue pairs). Intimal area and thickness, intima-media thickness, and intima to media area ratio were measured in hematoxylin and eosin stained cross-sections followed by pairwise statistical comparisons. The intimal area in stenotic and nonstenotic segments ranged from 1.25 to 11.61 mm 2 and 1.29 to 5.81 mm 2 , respectively. There was no significant difference between these 2 groups (P=.26). Maximal intimal thickness (P=.22), maximal intima-media thickness (P=.13), and intima to media area ratio (P=.73) were also similar between both types of segments. This preliminary study indicates that postoperative intimal hyperplasia by itself is not associated with the development of focal venous stenosis in 2-stage fistulas. Copyright © 2017 Elsevier Inc. All rights reserved.

A comprehensive morphometric analysis of the internal thoracic artery with emphasis on age, gender and left-to-right specific differences.

PubMed

Borović, Milica Labudovi; Borović, Saša; Marinković-Erić, Jelena; Todorović, Vera; Puškaš, Nela; Kočica, Mladen; Radak, Đorđe; Lačković, Vesna

2013-10-01

The aim of this analysis was the morphometric description of the internal thoracic artery (ITA) with an emphasis on age, gender and left-to-right specific differences, as well as on age and atherosclerosis related changes of the elastic skeleton. Forty eight arteries were obtained during forensic autopsies from 32 persons who had died of non-vascular causes. The following morphometric parameters were analyzed: thickness of the intima, the medial layer and the wall, the intima-to media-ratio and the elastic skeleton parameters. The intima thickness increases significantly with aging (ANOVA F=34.061, p⟨0.001), as does the intima-to-media ratio (ANOVA F=10.831, p⟨0.001). With aging, there is a significant increase in the thickness of the media (F=56.519; p⟨0.001) and of the wall (F=34.094; p⟨0,001). There is a significant increase in the media thickness during the development of atherosclerosis in the ITA (ANOVA F=11.848, p⟨0.001). No significant difference was found when these data were analyzed based on the left-to-right principle or depending on gender of the patients. However, the analysis of the elastic skeleton parameters indicated that the combined effects of aging, atherosclerosis and male gender lead to the degeneration of the elastic skeleton of the ITA. The grade of atherosclerosis gradually increases with aging as shown by morphometric analysis. The increase in the medial layer thickness suggests the potential for positive remodeling of the ITA during aging and atherosclerosis. The left/right position has no influence on morphometric parameters of the ITA, while male gender affects parameters of the elastic skeleton.

Effect of androgen replacement therapy on atherosclerotic risk markers in young-to-middle-aged men with idiopathic hypogonadotropic hypogonadism.

PubMed

Doğan, Berçem Ayçiçek; Karakılıç, Ersen; Tuna, Mazhar Müslüm; Arduç, Ayşe; Berker, Dilek; Güler, Serdar

2015-03-01

Idiopathic hypogonadotropic hypogonadism is a rare disorder. This study evaluated the effect of androgen replacement therapy on atherosclerotic risk markers in young-to-middle-aged men with this disorder. Forty-three male patients aged 30 (range: 24-39 years) who were newly diagnosed with idiopathic hypogonadotropic hypogonadism and 20 age-, sex- and weight-matched controls (range: 26-39 years) were included in the study. Androgen replacement therapy was given according to the Algorithm of Testosterone Therapy in Adult Men with Androgen Deficiency Syndromes (2010; Journal of Clinical Endocrinology and Metabolism, 95, 2536). The patients were assessed at a pretreatment visit and 3 and 6 months after the treatment. Inflammatory markers and lipid parameters were evaluated. Endothelial function was assessed with brachial flow-mediated dilation of a brachial artery and high-resolution ultrasonography of the carotid intima-media thickness. The carotid intima-media thickness (P < 0·001) was higher and the brachial flow-mediated diameter (P = 0·002) was lower in patients with idiopathic hypogonadotropic hypogonadism compared to the control subjects at the pretreatment visit. There was a negative correlation between the total testosterone level and carotid intima-media thickness (r = -0·556, P = <0·001). The carotid intima-media thickness and per cent flow-mediated diameter were significantly improved in the patient group 6 months after the androgen replacement therapy (P = 0·002 and 0·026, respectively). This study indicated that low total testosterone levels can be considered a significant marker of atherosclerosis in patients with idiopathic hypogonadotropic hypogonadism and that androgen replacement therapy significantly reduces atherosclerotic risk markers in these patients after 6 months. © 2014 John Wiley & Sons Ltd.

A Cross-Layer User Centric Vertical Handover Decision Approach Based on MIH Local Triggers

NASA Astrophysics Data System (ADS)

Rehan, Maaz; Yousaf, Muhammad; Qayyum, Amir; Malik, Shahzad

Vertical handover decision algorithm that is based on user preferences and coupled with Media Independent Handover (MIH) local triggers have not been explored much in the literature. We have developed a comprehensive cross-layer solution, called Vertical Handover Decision (VHOD) approach, which consists of three parts viz. mechanism for collecting and storing user preferences, Vertical Handover Decision (VHOD) algorithm and the MIH Function (MIHF). MIHF triggers the VHOD algorithm which operates on user preferences to issue handover commands to mobility management protocol. VHOD algorithm is an MIH User and therefore needs to subscribe events and configure thresholds for receiving triggers from MIHF. In this regard, we have performed experiments in WLAN to suggest thresholds for Link Going Down trigger. We have also critically evaluated the handover decision process, proposed Just-in-time interface activation technique, compared our proposed approach with prominent user centric approaches and analyzed our approach from different aspects.

Comparison between newer local anesthetics for myofascial pain syndrome management.

PubMed

Zaralidou, A Th; Amaniti, E N; Maidatsi, P G; Gorgias, N K; Vasilakos, D F

2007-06-01

Myofascial pain syndromes are characterized by the presence of painful loci within muscles, tendons or ligaments, called trigger points. Infiltration of these points with local anesthetics is often used as a treatment modality. The aim of the study was to comparatively evaluate 0.25% levobupivacaine and 0.25% ropivacaine for trigger point injection regarding pain on injection, treatment efficacy and duration of symptoms remission. Sixty-eight patients, suffering from myofascial pain syndromes, were randomly assigned to two groups to receive either levobupivacaine or ropivacaine for trigger-point injection. After completion of the procedure, patients were asked to rate pain during injection and efficacy of the treatment, based on immediate relief. Two weeks later, they were asked about the duration of this relief. Statistical analysis did not reveal significant differences between groups with respect to pain during injection, efficacy of the treatment and duration of pain relief. The two local anesthetics seem to be equally effective for trigger point infiltration. (c) 2007 Prous Science. All rights reserved.

Analyzing the Possibility of Dynamic Earthquake Triggering in Socorro, New Mexico

NASA Astrophysics Data System (ADS)

Morton, E.; Bilek, S. L.

2011-12-01

The release of energy during an earthquake changes the stress state and seismicity both locally and remotely. Far-field stress changes can lead to triggered earthquakes coinciding with the arrival of the surface waves. This dynamic triggering is found to occur in a variety of tectonic settings, but in particular magmatic regions. Here we test whether the Socorro Magma Body region in central New Mexico hosts triggered seismicity. Preliminary inspection of continuous network data in central New Mexico suggested a local triggered event with the passage of surface waves from an MW 6.9 event in 2009. For a more comprehensive view, we examine data from 379 earthquakes MW ≥ 6.0 between January 15, 2008 to March 13, 2010 recorded on the EarthScope USArray Transportable Network stations located within New Mexico and providing more dense coverage for better detectability. Waveforms from twenty EarthScope stations were windowed around the time of the large event, high-pass filtered at 5 Hz to remove low frequency signals and analyzed to detect high frequency triggered local earthquakes. For each possible trigger detected, waveforms from nine short-period stations in the Socorro Seismic Network were added to aid in locating the events. In the time period analyzed, twelve triggered events were detected. Only one of these events, on August 30, 2009, corresponded to the arrival of surface waves, occurring about a minute after their arrival. The majority of the triggered events occur well after the arrival of the surface waves, indicating that they are either independent of the main shock or the result of delayed dynamic triggering. Delayed dynamic triggering can occur hours or days after the passage of surface waves, and are marked by an increase in seismicity relative to background. Only one of the events, on September 18, 2009, occurred within the Socorro Magma Body area. The rest of these events occur spread throughout New Mexico. The widely spread distribution of possibly triggered events and the low ratio of triggers to main shocks indicates that the rifted magmatic region above the Socorro Magma Body is not particularly susceptible to dynamic triggering from remote main shocks. The lack of direct correspondence to a seismic phase can mean that the detected events may be independent (not triggered events), or the result of delayed dynamic triggering. A comparison to randomly chosen waveforms within the time period as background will reveal if the possible events are a result of delayed dynamic triggering or part of the background.

New modalities of ultrasound-based intima-media thickness, arterial stiffness and non-coronary vascular calcifications detection to assess cardiovascular risk.

PubMed

Flore, R; Ponziani, F R; Tinelli, G; Arena, V; Fonnesu, C; Nesci, A; Santoro, L; Tondi, P; Santoliquido, A

2015-04-01

Carotid intima-media thickness (c-IMT), arterial stiffness (AS) and vascular calcification (VC) are now considered important new markers of atherosclerosis and have been associated with increased prevalence of cardiovascular events. An accurate, reproducible and easy detection of these parameters could increase the prognostic value of the traditional cardiovascular risk factors in many subjects at low and intermediate risk. Today, c-IMT and AS can be measured by ultrasound, while cardiac computed tomography is the gold standard to quantify coronary VC, although concern about the reproducibility of the former and the safety of the latter have been raised. Nevertheless, a safe and reliable method to quantify non-coronary (i.e., peripheral) VC has not been detected yet. To review the most innovative and accurate ultrasound-based modalities of c-IMT and AS detection and to describe a novel UltraSound-Based Carotid, Aortic and Lower limbs Calcification Score (USB-CALCs, simply named CALC), allowing to quantify peripheral calcifications. Finally, to propose a system for cardiovascular risk reclassification derived from the global evaluation of "Quality Intima-Media Thickness", "Quality Arterial Stiffness", and "CALC score" in addition to the Framingham score.

A user friendly system for ultrasound carotid intima-media thickness image interpretation

NASA Astrophysics Data System (ADS)

Zhu, Xiangjun; Kendall, Christopher B.; Hurst, R. Todd; Liang, Jianming

2011-03-01

Assessment of Carotid Intima-Media Thickness (CIMT) by B-mode ultrasound is a technically mature and reproducible technology. Given the high morbidity, mortality and the large societal burden associated with CV diseases, as a safe yet inexpensive tool, CIMT is increasingly utilized for cardiovascular (CV) risk stratification. However, CIMT requires a precise measure of the thickness of the intima and media layers of the carotid artery that can be tedious, time consuming, and demand specialized expertise and experience. To this end, we have developed a highly user-friendly system for semiautomatic CIMT image interpretation. Our contribution is the application of active contour models (snake models) with hard constraints, leading to an accurate, adaptive and user-friendly border detection algorithm. A comparison study with the CIMT measurement software in Siemens Syngo® Arterial Health Package shows that our system gives a small bias in mean (0.049 +/-0.051mm) and maximum (0.010 +/- 0.083 mm) CIMT measures and offers a higher reproducibility (average correlation coefficients were 0.948 and 0.844 in mean and maximum CIMT respectively (P <0.001)). This superior performance is attributed to our novel interface design for hard constraints in the snake models.

Rationale and design of a multicenter randomized study for evaluating vascular function under uric acid control using the xanthine oxidase inhibitor, febuxostat: the PRIZE study.

PubMed

Oyama, Jun-Ichi; Tanaka, Atsushi; Sato, Yasunori; Tomiyama, Hirofumi; Sata, Masataka; Ishizu, Tomoko; Taguchi, Isao; Kuroyanagi, Takanori; Teragawa, Hiroki; Ishizaka, Nobukazu; Kanzaki, Yumiko; Ohishi, Mitsuru; Eguchi, Kazuo; Higashi, Yukihito; Yamada, Hirotsugu; Maemura, Koji; Ako, Junya; Bando, Yasuko K; Ueda, Shinichiro; Inoue, Teruo; Murohara, Toyoaki; Node, Koichi

2016-06-18

Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces endothelial dysfunction and inflammatory reactions in vascular systems, leading to atherosclerosis. Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. We designed the PRIZE study to evaluate the effects of febuxostat on a surrogate marker of cardiovascular disease risk, ultrasonography-based intima-media thickness of the carotid artery in patients with hyperuricemia. The study is a multicenter, prospective, randomized, open-label and blinded-endpoint evaluation (PROBE) design. A total of 500 patients with asymptomatic hyperuricemia (uric acid >7.0 mg/dL) and carotid intima-media thickness ≥1.1 mm will be randomized centrally to receive either febuxostat (10-60 mg/day) or non-pharmacological treatment. Randomization is carried out using the dynamic allocation method stratified according to age (<65, ≥65 year), gender, presence or absence of diabetes mellitus, serum uric acid (<8.0, ≥8.0 mg/dL), and carotid intima-media thickness (<1.3, ≥1.3 mm). In addition to administering the study drug, we will also direct lifestyle modification in all participants, including advice on control of body weight, sleep, exercise and healthy diet. Carotid intima-media thickness will be evaluated using ultrasonography performed by skilled technicians at a central laboratory. Follow-up will be continued for 24 months. The primary endpoint is percentage change in mean intima-media thickness of the common carotid artery 24 months after baseline, measured by carotid ultrasound imaging. PRIZE will be the first study to provide important data on the effects of febuxostat on atherosclerosis in patients with asymptomatic hyperuricemia. Trial Registration Unique trial Number, UMIN000012911 ( https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000015081&language=E ).

Carotid intima-media thickness progression to predict cardiovascular events in the general population (the PROG-IMT collaborative project): a meta-analysis of individual participant data.

PubMed

Lorenz, Matthias W; Polak, Joseph F; Kavousi, Maryam; Mathiesen, Ellisiv B; Völzke, Henry; Tuomainen, Tomi-Pekka; Sander, Dirk; Plichart, Matthieu; Catapano, Alberico L; Robertson, Christine M; Kiechl, Stefan; Rundek, Tatjana; Desvarieux, Moïse; Lind, Lars; Schmid, Caroline; DasMahapatra, Pronabesh; Gao, Lu; Ziegelbauer, Kathrin; Bots, Michiel L; Thompson, Simon G

2012-06-02

Carotid intima-media thickness (cIMT) is related to the risk of cardiovascular events in the general population. An association between changes in cIMT and cardiovascular risk is frequently assumed but has rarely been reported. Our aim was to test this association. We identified general population studies that assessed cIMT at least twice and followed up participants for myocardial infarction, stroke, or death. The study teams collaborated in an individual participant data meta-analysis. Excluding individuals with previous myocardial infarction or stroke, we assessed the association between cIMT progression and the risk of cardiovascular events (myocardial infarction, stroke, vascular death, or a combination of these) for each study with Cox regression. The log hazard ratios (HRs) per SD difference were pooled by random effects meta-analysis. Of 21 eligible studies, 16 with 36,984 participants were included. During a mean follow-up of 7·0 years, 1519 myocardial infarctions, 1339 strokes, and 2028 combined endpoints (myocardial infarction, stroke, vascular death) occurred. Yearly cIMT progression was derived from two ultrasound visits 2-7 years (median 4 years) apart. For mean common carotid artery intima-media thickness progression, the overall HR of the combined endpoint was 0·97 (95% CI 0·94-1·00) when adjusted for age, sex, and mean common carotid artery intima-media thickness, and 0·98 (0·95-1·01) when also adjusted for vascular risk factors. Although we detected no associations with cIMT progression in sensitivity analyses, the mean cIMT of the two ultrasound scans was positively and robustly associated with cardiovascular risk (HR for the combined endpoint 1·16, 95% CI 1·10-1·22, adjusted for age, sex, mean common carotid artery intima-media thickness progression, and vascular risk factors). In three studies including 3439 participants who had four ultrasound scans, cIMT progression did not correlate between occassions (reproducibility correlations between r=-0·06 and r=-0·02). The association between cIMT progression assessed from two ultrasound scans and cardiovascular risk in the general population remains unproven. No conclusion can be derived for the use of cIMT progression as a surrogate in clinical trials. Deutsche Forschungsgemeinschaft. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of carotid stiffness and intima-media thickness from ultrasound data: comparison between two methods.

PubMed

Bianchini, Elisabetta; Bozec, Erwan; Gemignani, Vincenzo; Faita, Francesco; Giannarelli, Chiara; Ghiadoni, Lorenzo; Demi, Marcello; Boutouyrie, Pierre; Laurent, Stéphane

2010-08-01

Increased arterial stiffness and carotid intima-media thickness (IMT) are considered independent predictors of cardiovascular events. The aim of this study was to compare a system recently developed in our laboratory for automatic assessment of these parameters from ultrasound image sequences to a reference radio frequency (RF) echo-tracking system. Common carotid artery scans of 21 patients with cardiovascular risk factors and 12 healthy volunteers were analyzed by both devices for the assessment of diameter (D), IMT, and distension (DeltaD). In the healthy volunteers, analyses were repeated twice to evaluate intraobserver variability. Agreement was evaluated by Bland-Altman analysis, whereas reproducibility was expressed as a coefficient of variation (CV). Regarding the agreement between the two systems, bias values +/- SD were 0.060 +/- 0.110 mm for D, -0.006 +/- 0.039 mm for IMT, and -0.016 +/- 0.039 mm for DeltaD. Intraobserver CVs were 2% +/- 2% for D, 5% +/- 5% for IMT, and 6% +/- 6% for DeltaD with the RF echo-tracking system and 2% +/- 1% for D, 6% +/- 6% for IMT, and 8% +/- 6% for DeltaD with our automated system. Although B-mode-based devices are less precise than RF-based ones, our automated system has good agreement with the reference method and comparable reproducibility, at least when high-quality images are analyzed. Hence, this study suggests that the presented system based on image processing from standard ultrasound scans is a suitable device for measuring IMT and local arterial stiffness parameters in clinical studies.

Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunsford, R.; Sun, Zhen; Maingi, Rajesh

The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper-single null discharges with an ITER like tungsten monoblock divertor. ELM triggering was a prompt response to granule injection, andmore » for granules of a sufficient size there was no evidence of a "trigger lag" phenomenon as observed in full metal machines. We also demonstrated that the triggering efficiency decreased with granule size during dynamic size scans. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. Furthermore, by simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined. Simulated 900 micron granules capable of triggering an ELM show a peaked mass deposition of 3.9 x 10 17 atoms per mm of penetration at a depth of approximately 5 cm past the separatrix.« less

Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

DOE PAGES

Lunsford, R.; Sun, Zhen; Maingi, Rajesh; ...

2017-12-19

The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper-single null discharges with an ITER like tungsten monoblock divertor. ELM triggering was a prompt response to granule injection, andmore » for granules of a sufficient size there was no evidence of a "trigger lag" phenomenon as observed in full metal machines. We also demonstrated that the triggering efficiency decreased with granule size during dynamic size scans. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. Furthermore, by simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined. Simulated 900 micron granules capable of triggering an ELM show a peaked mass deposition of 3.9 x 10 17 atoms per mm of penetration at a depth of approximately 5 cm past the separatrix.« less

Cooperative Robot Localization Using Event-Triggered Estimation

NASA Astrophysics Data System (ADS)

Iglesias Echevarria, David I.

It is known that multiple robot systems that need to cooperate to perform certain activities or tasks incur in high energy costs that hinder their autonomous functioning and limit the benefits provided to humans by these kinds of platforms. This work presents a communications-based method for cooperative robot localization. Implementing concepts from event-triggered estimation, used with success in the field of wireless sensor networks but rarely to do robot localization, agents are able to only send measurements to their neighbors when the expected novelty in this information is high. Since all agents know the condition that triggers a measurement to be sent or not, the lack of a measurement is therefore informative and fused into state estimates. In the case agents do not receive either direct nor indirect measurements of all others, the agents employ a covariance intersection fusion rule in order to keep the local covariance error metric bounded. A comprehensive analysis of the proposed algorithm and its estimation performance in a variety of scenarios is performed, and the algorithm is compared to similar cooperative localization approaches. Extensive simulations are performed that illustrate the effectiveness of this method.

Event-triggered output feedback control for distributed networked systems.

PubMed

Mahmoud, Magdi S; Sabih, Muhammad; Elshafei, Moustafa

2016-01-01

This paper addresses the problem of output-feedback communication and control with event-triggered framework in the context of distributed networked control systems. The design problem of the event-triggered output-feedback control is proposed as a linear matrix inequality (LMI) feasibility problem. The scheme is developed for the distributed system where only partial states are available. In this scheme, a subsystem uses local observers and share its information to its neighbors only when the subsystem's local error exceeds a specified threshold. The developed method is illustrated by using a coupled cart example from the literature. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Local nutrient regimes determine site-specific environmental triggers of cyanobacterial and microcystin variability in urban lakes

NASA Astrophysics Data System (ADS)

Sinang, S. C.; Reichwaldt, E. S.; Ghadouani, A.

2014-10-01

Toxic cyanobacterial blooms in urban lakes present serious health hazards to humans and animals and require effective management strategies. In the management of toxic cyanobacteria blooms, understanding the roles of environmental factors is crucial. To date, a range of environmental factors have been proposed as potential triggers for the spatiotemporal variability of cyanobacterial biomass and microcystins in freshwater systems. However, the environmental triggers of cyanobacteria and microcystin variability remain a subject of debate due to contrasting findings. This issue has raised the question if the environmental triggers are site-specific and unique between water bodies. In this study, we investigated the site-specificity of environmental triggers for cyanobacterial bloom and cyanotoxins dynamics. Our study suggests that cyanobacterial dominance and cyanobacterial microcystin content variability were significantly correlated to phosphorus and iron concentrations. However, the correlations between phosphorus and iron with cyanobacterial biomass and microcystin variability were not consistent between lakes, thus suggesting a site specificity of these environmental factors. The discrepancies in the correlations could be explained by differences in local nutrient concentration and the cyanobacterial community in the systems. The findings of this study suggest that identification of site-specific environmental factors under unique local conditions is an important strategy to enhance positive outcomes in cyanobacterial bloom control measures.

Prompt triggering of edge localized modes through lithium granule injection on EAST

NASA Astrophysics Data System (ADS)

Lunsford, Robert; Sun, Z.; Hu, J. S.; Xu, W.; Zuo, G. Z.; Gong, X. Z.; Wan, B. N.; Li, J. G.; Huang, M.; Maingi, R.; Diallo, A.; Tritz, K.; the EAST Team

2017-10-01

We report successful triggering of edge localized mode (ELMs) in EAST with Lithium (Li) micropellets, and the observed dependence of ELM triggering efficiency on granule size. ELM control is essential for successful ITER operation throughout the entire campaign, relying on magnetic perturbations for ELM suppression and ELM frequency enhancement via pellet injection. To separate the task of fueling from ELM pacing, we initiate the prompt generation of ELMs via impurity granule injection. Lithium granules ranging in size from 200 - 1000 microns are mechanically injected into upper-single null EAST long pulse H-mode discharges. The injections are monitored for their effect on high Z impurity accumulation and to assess the pressure perturbation required for reliable ELM triggering. We have determined that granules of diameter larger than 600 microns (corresponding to 5.2 x 1018 Li atoms) are successful at triggering ELMs more than 90% of the time. The triggering efficiency drops precipitously to less than 40% as the granule size is reduced to 400 microns (1.5 x 1018 Li atoms), indicating a triggering threshold has been crossed. Using this information an optimal impurity granule size which will regularly trigger a prompt ELM in these EAST discharges is determined. Coupling these results with alternate discharge scenarios on EAST and similar experiments performed on DIII-D provides the possibility of extrapolation to future devices.

Remotely triggered earthquakes following moderate main shocks

USGS Publications Warehouse

Hough, S.E.

2007-01-01

Since 1992, remotely triggered earthquakes have been identified following large (M > 7) earthquakes in California as well as in other regions. These events, which occur at much greater distances than classic aftershocks, occur predominantly in active geothermal or volcanic regions, leading to theories that the earthquakes are triggered when passing seismic waves cause disruptions in magmatic or other fluid systems. In this paper, I focus on observations of remotely triggered earthquakes following moderate main shocks in diverse tectonic settings. I summarize evidence that remotely triggered earthquakes occur commonly in mid-continent and collisional zones. This evidence is derived from analysis of both historic earthquake sequences and from instrumentally recorded M5-6 earthquakes in eastern Canada. The latter analysis suggests that, while remotely triggered earthquakes do not occur pervasively following moderate earthquakes in eastern North America, a low level of triggering often does occur at distances beyond conventional aftershock zones. The inferred triggered events occur at the distances at which SmS waves are known to significantly increase ground motions. A similar result was found for 28 recent M5.3-7.1 earthquakes in California. In California, seismicity is found to increase on average to a distance of at least 200 km following moderate main shocks. This supports the conclusion that, even at distances of ???100 km, dynamic stress changes control the occurrence of triggered events. There are two explanations that can account for the occurrence of remotely triggered earthquakes in intraplate settings: (1) they occur at local zones of weakness, or (2) they occur in zones of local stress concentration. ?? 2007 The Geological Society of America.

An immunohistochemical analysis of folate receptor beta expression and distribution in giant cell arteritis - a pilot study

PubMed Central

Albano-Aluquin, Shirley; Malysz, Jozef; Aluquin, Vincent R; Ratnam, Manohar; Olsen, Nancy

2017-01-01

Background: Giant cell arteritis (GCA) is a chronic vasculitis of large and medium vessels in which no targetable biomarkers exist to allow selective treatment, predict disease activity and monitor therapeutic responses. The accessibility of the temporal artery (TA) for biopsy allows morphologic studies to characterize macrophages and T cells in the microenvironment of the arterial wall. We evaluated the expression of folate receptor beta (FRB), a candidate diagnostic/therapeutic biomarker, compared its expression with key macrophage markers and correlated it with GCA severity. Methods: Formalin-fixed paraffin-embedded tissue sections were examined from 6 patients with GCA and 2 controls. Immunohistochemistry was performed using FRB, ETB, CD68 and CD3 antibodies to evaluate for activated macrophages and T cells, assess FRB distribution along the intima, media and adventitial layers and composition of inflammatory infiltrates. We compared the expression of FRB, ETB and CD68 in GCA versus negative controls and in severe (with visual loss) versus mild (without visual loss) disease. Results: In GCA, moderate to severe inflammation was accompanied by >90% destruction of the internal elastic lamina. Macrophages comprised 36.3 ± 4.1% while CD3+ lymphocytes accounted for 61.7 ± 4.1% of total leukocytes. FRB was selectively expressed in macrophages and localized to the adventitia. GCA patients had marginally increased median FRB (9.8 cells/hpf vs. 0; p=0.095), ETB (20.5 vs. 0; p=0.095) and CD68 (38.8 vs. 5; p=0.071) expression versus controls. ETB was found in endothelial cells, smooth muscle cells and macrophages in intima/media. FRB positively correlated with ETB (r=0.90; p-0.037) and CD68 levels (r=0.90; p=0.037). ETB expression positively correlated with CD68 (r=1.0; p<0.0001). There was no difference in FRB between severe and mild GCA. Conclusion: FRB is a potential diagnostic and therapeutic biomarker with restricted expression in GCA macrophages. FRB+ macrophages localized to the adventitia and their expression correlated with ETB and CD68 macrophages, suggesting that they contribute to GCA pathogenesis. PMID:29348986

Effects of thyroxine replacement on endothelial function and carotid artery intima-media thickness in female patients with mild subclinical hypothyroidism

PubMed Central

Cabral, Monica Dias; Teixeira, Patricia; Soares, Debora; Leite, Sandra; Salles, Elizabeth; Waisman, Mario

2011-01-01

BACKGROUND: Previous studies have suggested an association between subclinical hypothyroidism and coronary artery disease that could be related to changes in serum lipids or endothelial dysfunction. METHODS: Thirty-two female subclinical hypothyroidism patients were randomly assigned to 12 months of L-thyroxine replacement or no treatment. Endothelial function was measured by the flow-mediated vasodilatation of the brachial artery, as well as mean carotid artery intima-media thickness, and lipid profiles were studied at baseline and after 12 months of follow-up. RESULTS: The mean (±SD) serum thyroid-stimulating hormone levels in the L-thyroxine replacement and control groups were 6.09±1.32 and 6.27±1.39 µUI/ml, respectively. No relationship between carotid artery intima-media thickness or brachial flow-mediated vasodilatation and free T4 and serum thyroid-stimulating hormone was found. The median L-T4 dose was 44.23±18.13 µg/day. After 12 months, there was a significant decrease in the flow-mediated vasodilatation in the subclinical hypothyroidism control group (before: 17.33±7.88 to after: 13.1±4.75%, p = 0.03), but there were no significant differences in flow-mediated vasodilatation in the L-thyroxine treated group (before: 16.81±7.0 to after: 18.52±7.44%, p = 0.39). We did not find any significant change in mean carotid intima-media thickness after 12 months of L-thyroxine treatment. CONCLUSION: Replacement therapy prevents a decline in flow-mediated vasodilatation with continuation of the subclinical hypothyroidism state. Large prospective multicenter placebo-controlled trials are necessary to investigate endothelial physiology further in subclinical hypothyroidism patients and to define the role of L-thyroxine therapy in improving endothelial function in these patients. PMID:21915478

Inflammatory Obesity Phenotypes, Gender Effects, and Subclinical Atherosclerosis in African Americans: The Jackson Heart Study.

PubMed

Lin, Albert; Lacy, Mary E; Eaton, Charles; Correa, Adolfo; Wu, Wen-Chih

2016-12-01

Reasons for variations in atherosclerotic burden among individuals with similar levels of obesity are poorly understood, especially in African Americans. This study examines whether high-sensitivity C-reactive protein (hsCRP) is useful for discriminating between benign and high-risk obesity phenotypes for subclinical atherosclerosis in African Americans. Participants from the Jackson Heart Study (n=4682) were stratified into 4 phenotypes based on the presence of National Heart and Lung and Blood Institute definition of obesity or obesity-equivalent (body mass index ≥30 or body mass index 25-30 with waist circumference >102 cm in men and >88 cm in women) and inflammation by hsCRP ≥2 mg/L. Using multivariate regression models, we conducted cross-sectional analyses of the association between inflammatory obesity phenotypes and subclinical atherosclerosis determined by carotid intima-media thickness or coronary artery calcium scores. Sex-specific analyses were conducted given significant interaction for gender (P=0.03). The prevalence of obesity or equivalent was 65%, of which 30% did not have inflammation. Conversely, 37% of nonobese individuals had inflammation. Among nonobese men, hsCRP ≥2 mg/L identified a subset of individuals with higher carotid intima-media thickness (adjusted mean difference =0.05, 95% confidence interval 0.02, 0.08 mm) compared with their noninflammatory counterparts. Among obese men, hsCRP <2 mg/L identified a subset of individuals with lower coronary artery calcium compared with their inflammatory counterparts. Among women, associations between hsCRP and carotid intima-media thickness or coronary artery calcium were not found. In the largest African American population-based cohort to date, hsCRP was useful in identifying a subset of nonobese men with higher carotid intima-media thickness, but not in women. hsCRP did not identify a subset of obese individuals with less subclinical atherosclerosis. © 2016 American Heart Association, Inc.

Common carotid artery intima-media thickness is as good as carotid intima-media thickness of all carotid artery segments in improving prediction of coronary heart disease risk in the Atherosclerosis Risk in Communities (ARIC) study.

PubMed

Nambi, Vijay; Chambless, Lloyd; He, Max; Folsom, Aaron R; Mosley, Tom; Boerwinkle, Eric; Ballantyne, Christie M

2012-01-01

Carotid intima-media thickness (CIMT) and plaque information can improve coronary heart disease (CHD) risk prediction when added to traditional risk factors (TRF). However, obtaining adequate images of all carotid artery segments (A-CIMT) may be difficult. Of A-CIMT, the common carotid artery intima-media thickness (CCA-IMT) is relatively more reliable and easier to measure. We evaluated whether CCA-IMT is comparable to A-CIMT when added to TRF and plaque information in improving CHD risk prediction in the Atherosclerosis Risk in Communities (ARIC) study. Ten-year CHD risk prediction models using TRF alone, TRF + A-CIMT + plaque, and TRF + CCA-IMT + plaque were developed for the overall cohort, men, and women. The area under the receiver operator characteristic curve (AUC), per cent individuals reclassified, net reclassification index (NRI), and model calibration by the Grønnesby-Borgan test were estimated. There were 1722 incident CHD events in 12 576 individuals over a mean follow-up of 15.2 years. The AUC for TRF only, TRF + A-CIMT + plaque, and TRF + CCA-IMT + plaque models were 0.741, 0.754, and 0.753, respectively. Although there was some discordance when the CCA-IMT + plaque- and A-CIMT + plaque-based risk estimation was compared, the NRI and clinical NRI (NRI in the intermediate-risk group) when comparing the CIMT models with TRF-only model, per cent reclassified, and test for model calibration were not significantly different. Coronary heart disease risk prediction can be improved by adding A-CIMT + plaque or CCA-IMT + plaque information to TRF. Therefore, evaluating the carotid artery for plaque presence and measuring CCA-IMT, which is easier and more reliable than measuring A-CIMT, provide a good alternative to measuring A-CIMT for CHD risk prediction.

Endogenous Cholesterol Excretion Is Negatively Associated With Carotid Intima-Media Thickness in Humans.

PubMed

Lin, Xiaobo; Racette, Susan B; Ma, Lina; Wallendorf, Michael; Dávila-Román, Victor G; Ostlund, Richard E

2017-12-01

Epidemiological studies strongly suggest that lipid factors independent of low-density lipoprotein cholesterol contribute significantly to cardiovascular disease risk. Because circulating lipoproteins comprise only a small fraction of total body cholesterol, the mobilization and excretion of cholesterol from plasma and tissue pools may be an important determinant of cardiovascular disease risk. Our hypothesis is that fecal excretion of endogenous cholesterol is protective against atherosclerosis. Cholesterol metabolism and carotid intima-media thickness were quantitated in 86 nondiabetic adults. Plasma cholesterol was labeled by intravenous infusion of cholesterol-d 7 solubilized in a lipid emulsion and dietary cholesterol by cholesterol-d 5 and the nonabsorbable stool marker sitostanol-d 4 . Plasma and stool samples were collected while subjects consumed a cholesterol- and phytosterol-controlled metabolic kitchen diet and were analyzed by mass spectrometry. Carotid intima-media thickness was negatively correlated with fecal excretion of endogenous cholesterol ( r =-0.426; P <0.0001), total cholesterol ( r =-0.472; P ≤0.0001), and daily percent excretion of cholesterol from the rapidly mixing cholesterol pool ( r =-0.343; P =0.0012) and was positively correlated with percent cholesterol absorption ( r =+0.279; P =0.0092). In a linear regression model controlling for age, sex, systolic blood pressure, hemoglobin A1c, low-density lipoprotein, high-density lipoprotein cholesterol, and statin drug use, fecal excretion of endogenous cholesterol remained significant ( P =0.0008). Excretion of endogenous cholesterol is strongly, independently, and negatively associated with carotid intima-media thickness. The reverse cholesterol transport pathway comprising the intestine and the rapidly mixing plasma, and tissue cholesterol pool could be an unrecognized determinant of cardiovascular disease risk not reflected in circulating lipoproteins. Further work is needed to relate measures of reverse cholesterol transport to atherosclerotic disease. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01603758. © 2017 American Heart Association, Inc.

Carotid intima-media thickness progression to predict cardiovascular events in the general population (the PROG-IMT collaborative project): a meta-analysis of individual participant data

PubMed Central

Lorenz, Matthias W; Polak, Joseph F; Kavousi, Maryam; Mathiesen, Ellisiv B; Völzke, Henry; Tuomainen, Tomi-Pekka; Sander, Dirk; Plichart, Matthieu; Catapano, Alberico L; Robertson, Christine M; Kiechl, Stefan; Rundek, Tatjana; Desvarieux, Moïse; Lind, Lars; Schmid, Caroline; DasMahapatra, Pronabesh; Gao, Lu; Ziegelbauer, Kathrin; Bots, Michiel L; Thompson, Simon G

2013-01-01

Summary Background Carotid intima-media thickness (cIMT) is related to the risk of cardiovascular events in the general population. An association between changes in cIMT and cardiovascular risk is frequently assumed but has rarely been reported. Our aim was to test this association. Methods We identified general population studies that assessed cIMT at least twice and followed up participants for myocardial infarction, stroke, or death. The study teams collaborated in an individual participant data meta-analysis. Excluding individuals with previous myocardial infarction or stroke, we assessed the association between cIMT progression and the risk of cardiovascular events (myocardial infarction, stroke, vascular death, or a combination of these) for each study with Cox regression. The log hazard ratios (HRs) per SD difference were pooled by random effects meta-analysis. Findings Of 21 eligible studies, 16 with 36 984 participants were included. During a mean follow-up of 7·0 years, 1519 myocardial infarctions, 1339 strokes, and 2028 combined endpoints (myocardial infarction, stroke, vascular death) occurred. Yearly cIMT progression was derived from two ultrasound visits 2–7 years (median 4 years) apart. For mean common carotid artery intima-media thickness progression, the overall HR of the combined endpoint was 0·97 (95% CI 0·94–1·00) when adjusted for age, sex, and mean common carotid artery intima-media thickness, and 0·98 (0·95–1·01) when also adjusted for vascular risk factors. Although we detected no associations with cIMT progression in sensitivity analyses, the mean cIMT of the two ultrasound scans was positively and robustly associated with cardiovascular risk (HR for the combined endpoint 1·16, 95% CI 1·10–1·22, adjusted for age, sex, mean common carotid artery intima-media thickness progression, and vascular risk factors). In three studies including 3439 participants who had four ultrasound scans, cIMT progression did not correlate between occassions (reproducibility correlations between r=−0·06 and r=−0·02). Interpretation The association between cIMT progression assessed from two ultrasound scans and cardiovascular risk in the general population remains unproven. No conclusion can be derived for the use of cIMT progression as a surrogate in clinical trials. Funding Deutsche Forschungsgemeinschaft. PMID:22541275

Association between air pollution and coronary artery calcification within six metropolitan areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): a longitudinal cohort study.

PubMed

Kaufman, Joel D; Adar, Sara D; Barr, R Graham; Budoff, Matthew; Burke, Gregory L; Curl, Cynthia L; Daviglus, Martha L; Diez Roux, Ana V; Gassett, Amanda J; Jacobs, David R; Kronmal, Richard; Larson, Timothy V; Navas-Acien, Ana; Olives, Casey; Sampson, Paul D; Sheppard, Lianne; Siscovick, David S; Stein, James H; Szpiro, Adam A; Watson, Karol E

2016-08-13

Long-term exposure to fine particulate matter less than 2.5 μm in diameter (PM2.5) and traffic-related air pollutant concentrations are associated with cardiovascular risk. The disease process underlying these associations remains uncertain. We aim to assess association between long-term exposure to ambient air pollution and progression of coronary artery calcium and common carotid artery intima-media thickness. In this prospective 10-year cohort study, we repeatedly measured coronary artery calcium by CT in 6795 participants aged 45-84 years enrolled in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) in six metropolitan areas in the USA. Repeated scans were done for nearly all participants between 2002 and 2005, for a subset of participants between 2005 and 2007, and for half of all participants between 2010 and 2012. Common carotid artery intima-media thickness was measured by ultrasound in all participants at baseline and in 2010-12 for 3459 participants. Residence-specific spatio-temporal pollution concentration models, incorporating community-specific measurements, agency monitoring data, and geographical predictors, estimated concentrations of PM2.5 and nitrogen oxides (NOX) between 1999 and 2012. The primary aim was to examine the association between both progression of coronary artery calcium and mean carotid artery intima-media thickness and long-term exposure to ambient air pollutant concentrations (PM2.5, NOX, and black carbon) between examinations and within the six metropolitan areas, adjusting for baseline age, sex, ethnicity, socioeconomic characteristics, cardiovascular risk factors, site, and CT scanner technology. In this population, coronary calcium increased on average by 24 Agatston units per year (SD 58), and intima-media thickness by 12 μm per year (10), before adjusting for risk factors or air pollutant exposures. Participant-specific pollutant concentrations averaged over the years 2000-10 ranged from 9.2-22.6 μg PM2.5/m(3) and 7.2-139.2 parts per billion (ppb) NOX. For each 5 μg PM2.5/m(3) increase, coronary calcium progressed by 4.1 Agatston units per year (95% CI 1.4-6.8) and for each 40 ppb NOX coronary calcium progressed by 4.8 Agatston units per year (0.9-8.7). Pollutant exposures were not associated with intima-media thickness change. The estimate for the effect of a 5 μg/m(3) higher long-term exposure to PM2.5 in intima-media thickness was -0.9 μm per year (95% CI -3.0 to 1.3). For 40 ppb higher NOX, the estimate was 0.2 μm per year (-1.9 to 2.4). Increased concentrations of PM2.5 and traffic-related air pollution within metropolitan areas, in ranges commonly encountered worldwide, are associated with progression in coronary calcification, consistent with acceleration of atherosclerosis. This study supports the case for global efforts of pollution reduction in prevention of cardiovascular diseases. US Environmental Protection Agency and US National Institutes of Health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dynamic Earthquake Triggering on Seismogenic Faults in Oklahoma

NASA Astrophysics Data System (ADS)

Qin, Y.; Chen, X.; Peng, Z.; Aiken, C.

2016-12-01

Regions with high pore pressure are generally more susceptible to dynamic triggering from transient stress change caused by surface wave of distant earthquakes. The stress threshold from triggering studies can help understand the stress state of seismogenic faults. The recent dramatic seismicity increase in central US provides a rich database for assessing dynamic triggering phenomena. We begin our study by conducting a systematic analysis of dynamic triggering for the continental U.S using ANSS catalog (with magnitude of completeness Mc=3) from 49 global mainshocks (Ms>6.5, depth<100km, estimated dynamic stress>1kPa). We calculate β value for each 1° by 1° bins in 30 days before and 10 days after the mainshock. To identify regions that experience triggering from a distant mainshock, we generate a stacked map using β≥2 - which represents significant seismicity rate increase. As expected, the geothermal and volcanic fields in California show clear response to distant earthquakes. We also note areas in Oklahoma and north Texas show enhanced triggering, where wastewater-injection induced seismicity are occurring. Next we focus on Oklahoma and use a local catalog from Oklahoma Geological Survey with lower completeness threshold Mc to calculate the beta map in 0.2° by 0.2° bins for each selected mainshock to obtain finer spatial resolutions of the triggering behavior. For those grids with β larger than 2.0, we use waveforms from nearby stations to search for triggered events. The April 2015 M7.8 Nepal earthquake causes a statistically significant increase of local seismicity (β=3.5) in the Woodward area (west Oklahoma) during an on-going earthquake sequence. By visually examining the surface wave from the nearest station, we identify 3 larger local events, and 10 additional smaller events with weaker but discernable amplitude. Preliminary analysis shows that the triggering is related to Rayleigh wave, which would cause dilatational or shear stress changes along the strike direction of Woodward fault, given the azimuth between Nepal and Oklahoma. Our next step is to apply matched-filter technique to generate a complete catalog for an extended period of time, in order to better understand dynamic triggering and spatio-temporal evolution of this sequence - one of the largest sequences in western Oklahoma.

Self-defensive antibiotic-loaded layer-by-layer coatings: Imaging of localized bacterial acidification and pH-triggering of antibiotic release.

PubMed

Albright, Victoria; Zhuk, Iryna; Wang, Yuhao; Selin, Victor; van de Belt-Gritter, Betsy; Busscher, Henk J; van der Mei, Henny C; Sukhishvili, Svetlana A

2017-10-01

Self-defensive antibiotic-loaded coatings have shown promise in inhibiting growth of pathogenic bacteria adhering to biomaterial implants and devices, but direct proof that their antibacterial release is triggered by bacterially-induced acidification of the immediate environment under buffered conditions remained elusive. Here, we demonstrate that Staphylococcus aureus and Escherichia coli adhering to such coatings generate highly localized acidification, even in buffered conditions, to activate pH-triggered, self-defensive antibiotic release. To this end, we utilized chemically crosslinked layer-by-layer hydrogel coatings of poly(methacrylic acid) with a covalently attached pH-sensitive SNARF-1 fluorescent label for imaging, and unlabeled-antibiotic (gentamicin or polymyxin B) loaded coatings for antibacterial studies. Local acidification of the coatings induced by S. aureus and E. coli adhering to the coatings was demonstrated by confocal-laser-scanning-microscopy via wavelength-resolved imaging. pH-triggered antibiotic release under static, small volume conditions yielded high bacterial killing efficiencies for S. aureus and E. coli. Gentamicin-loaded films retained their antibacterial activity against S. aureus under fluid flow in buffered conditions. Antibacterial activity increased with the number of polymer layers in the films. Altogether, pH-triggered, self-defensive antibiotic-loaded coatings become activated by highly localized acidification in the immediate environment of an adhering bacterium, offering potential for clinical application with minimized side-effects. Polymeric coatings were created that are able to uptake and selectively release antibiotics upon stimulus by adhering bacteria in order to understand the fundamental mechanisms behind pH-triggered antibiotic release as a potential way to prevent biomaterial-associated infections. Through fluorescent imaging studies, this work importantly shows that adhering bacteria produce highly localized pH changes even in buffer. Accordingly such coatings only demonstrate antibacterial activity by antibiotic release in the presence of adhering bacteria. This is clinically important, because ad libitum releasing antibiotic coatings usually show a burst release and have often lost their antibiotic content when bacteria adhere. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of periodontal treatment on carotid intima-media thickness in patients with lifestyle-related diseases: Japanese prospective multicentre observational study.

PubMed

Kudo, Chieko; Shin, Wee Soo; Sasaki, Nobuhiro; Harai, Kazuo; Kato, Kai; Seino, Hiroaki; Goke, Eiji; Fujino, Takemasa; Kuribayashi, Nobuichi; Pearce, Youko Onuki; Taira, Masato; Matsushima, Ryoji; Minabe, Masato; Takashiba, Shogo

2018-01-12

Atherosclerosis, a chronic inflammatory disease in arterial blood vessels, is one of the major causes of death in worldwide. Meanwhile, periodontal disease is a chronic inflammatory disease caused by infection with periodontal pathogens such as P. gingivalis (Porphyromonas gingivalis). Several studies have reported association between periodontal infection and atherosclerosis, but direct investigation about the effects of periodontal treatment on atherosclerosis has not been reported. We have planned Japanese local clinics to determine the relationship between periodontal disease and atherosclerosis under collaborative with medical and dental care. A prospective, multicentre, observational study was conducted including 38 medical patients with lifestyle-related diseases in the stable period under consultation at participating medical clinics and 92 periodontal patients not undergoing medical treatment but who were consulting at participating dental clinics. Systemic and periodontal examinations were performed before and after periodontal treatment. At baseline, LDL-C (low-density lipoprotein cholesterol) levels and percentage (%) of mobile teeth were positively related to plasma IgG (immunoglobulin) antibody titer against P. gingivalis with multivariate analysis. Corresponding to improvements in periodontal clinical parameters after treatment, right and left max IMT (maximum intima-media thickness) levels were decreased significantly after treatment (SPT-S: start of supportive periodontal therapy, SPT-1y: at 1 year under SPT, and SPT-3y: at 3 years under SPT). The present study has clarified our previous univariate analysis results, wherein P. gingivalis infection was positively associated with progression of atherosclerosis. Thus, routine screening using plasma IgG antibody titer against P. gingivalis and periodontal treatment under collaborative with medical and dental care may prevent cardiovascular accidents caused by atherosclerosis.

High Spatial Inhomogeneity in the Intima-Media Thickness of the Common Carotid Artery is Associated with a Larger Degree of Stenosis in the Internal Carotid Artery: The PARISK Study.

PubMed

Steinbuch, Jeire; van Dijk, Anouk C; Schreuder, Floris H B M; Truijman, Martine T B; de Rotte, Alexandra A J; Nederkoorn, Paul J; van der Lugt, Aad; Hermeling, Evelien; Hoeks, Arnold P G; Mess, Werner H

2017-10-01

Purpose  Inhomogeneity of arterial wall thickness may be indicative of distal plaques. This study investigates the intra-subject association between relative spatial intima-media thickness (IMT) inhomogeneity of the common carotid artery (CCA) and the degree of stenosis of plaques in the internal carotid artery (ICA). Materials and Methods  We included 240 patients with a recent ischemic stroke or transient ischemic attack and mild-to-moderate stenosis in the ipsilateral ICA. IMT inhomogeneity was extracted from B-mode ultrasound recordings. The degree of ICA stenosis was assessed on CT angiography according to the European Carotid Surgery Trial method. Patients were divided into groups with a low (≤ 2 %) and a high (> 2 %) IMT inhomogeneity scaled with respect to the local end-diastolic diameter. Results  182 patients had suitable CT and ultrasound measurements. Relative CCA-IMT inhomogeneity was similar for the symptomatic and asymptomatic side (difference: 0.02 %, p = 0.85). High relative IMT inhomogeneity was associated with a larger IMT (difference: 235 µm, p < 0.001) and larger degree of ICA stenosis (difference: 5 %, p = 0.023) which remained significant (p = 0.016) after adjustment for common risk factors. Conclusion  Regardless of common risk factors, high relative CCA-IMT inhomogeneity is associated with a greater degree of ICA stenosis and is therefore indicative of atherosclerotic disease. The predictive value of CCA-IMT inhomogeneity for plaque progression and recurrence of cerebrovascular symptoms will be determined in the follow-up phase of PARISK. © Georg Thieme Verlag KG Stuttgart · New York.

[Stem and progenitor cells in biostructure of blood vessel walls].

PubMed

Korta, Krzysztof; Kupczyk, Piotr; Skóra, Jan; Pupka, Artur; Zejler, Paweł; Hołysz, Marcin; Gajda, Mariusz; Nowakowska, Beata; Barć, Piotr; Dorobisz, Andrzej T; Dawiskiba, Tomasz; Szyber, Piotr; Bar, Julia

2013-09-18

Development of vascular and hematopoietic systems during organogenesis occurs at the same time. During vasculogenesis, a small part of cells does not undergo complete differentiation but stays on this level, "anchored" in tissue structures described as stem cell niches. The presence of blood vessels within tissue stem cell niches is typical and led to identification of niches and ensures that they are functioning. The three-layer biostructure of vessel walls for artery and vein, tunica: intima, media and adventitia, for a long time was defined as a mechanical barrier between vessel light and the local tissue environment. Recent findings from vascular biology studies indicate that vessel walls are dynamic biostructures, which are equipped with stem and progenitor cells, described as vascular wall-resident stem cells/progenitor cells (VW-SC/PC). Distinct zones for vessel wall harbor heterogeneous subpopulations of VW-SC/PC, which are described as "subendothelial or vasculogenic zones". Recent evidence from in vitro and in vivo studies show that prenatal activity of stem and progenitor cells is not only limited to organogenesis but also exists in postnatal life, where it is responsible for vessel wall homeostasis, remodeling and regeneration. It is believed that VW-SC/PC could be engaged in progression of vascular disorders and development of neointima. We would like to summarize current knowledge about mesenchymal and progenitor stem cell phenotype with special attention to distribution and biological properties of VW-SC/PC in biostructures of intima, media and adventitia niches. It is postulated that in the near future, niches for VW-SC/PC could be a good source of stem and progenitor cells, especially in the context of vessel tissue bioengineering as a new alternative to traditional revascularization therapies.

Anaesthetic injection versus ischemic compression for the pain relief of abdominal wall trigger points in women with chronic pelvic pain.

PubMed

Montenegro, Mary L L S; Braz, Carolina A; Rosa-e-Silva, Julio C; Candido-dos-Reis, Francisco J; Nogueira, Antonio A; Poli-Neto, Omero B

2015-12-01

Chronic pelvic pain is a common condition among women, and 10 to 30 % of causes originate from the abdominal wall, and are associated with trigger points. Although little is known about their pathophysiology, variable methods have been practiced clinically. The purpose of this study was to evaluate the efficacy of local anaesthetic injections versus ischemic compression via physical therapy for pain relief of abdominal wall trigger points in women with chronic pelvic pain. We conducted a parallel group randomized trial including 30 women with chronic pelvic pain with abdominal wall trigger points. Subjects were randomly assigned to one of two intervention groups. One group received an injection of 2 mL 0.5 % lidocaine without a vasoconstrictor into a trigger point. In the other group, ischemic compression via physical therapy was administered at the trigger points three times, with each session lasting for 60 s, and a rest period of 30 s between applications. Both treatments were administered during one weekly session for four weeks. Our primary outcomes were satisfactory clinical response rates and percentages of pain relief. Our secondary outcomes are pain threshold and tolerance at the trigger points. All subjects were evaluated at baseline and 1, 4, and 12 weeks after the interventions. The study was conducted at a tertiary hospital that was associated with a university providing assistance predominantly to working class women who were treated by the public health system. Clinical response rates and pain relief were significantly better at 1, 4, and 12 weeks for those receiving local anaesthetic injections than ischemic compression via physical therapy. The pain relief of women treated with local anaesthetic injections progressively improved at 1, 4, and 12 weeks after intervention. In contrast, women treated with ischemic compression did not show considerable changes in pain relief after intervention. In the local anaesthetic injection group, pain threshold and tolerance improved with time in the absence of significant differences between groups. Lidocaine injection seems to be better for reducing the severity of chronic pelvic pain secondary to abdominal wall trigger points compared to ischemic compression via physical therapy. ClinicalTrials.gov NCT00628355. Date of registration: February 25, 2008.

Pulmonary vascular disease in a rabbit a high altitude

NASA Astrophysics Data System (ADS)

Heath, Donald; Williams, David; Rios-Datenz, Jaime; Gosney, John

1990-03-01

A male weanling rabbit of the New Zealand White strain, born and living at an altitude of 3800 m in La Paz, Bolivia, developed right ventricular hypertrophy. This was found to be associated with growth of vascular smooth muscle cells in the intima of pulmonary arterioles, and contrasted with muscularization of the walls of pulmonary arterioles, without extension into the intima, found in a healthy, high-altitude control rabbit of the same strain. A low-altitude control showed no such muscularization. It is concluded that alveolar hypoxia, acting directly or through an intermediate agent, is a growth factor for vascular smooth muscle cells in pulmonary arterioles. This is the first report of pulmonary vascular disease due to high altitude in rabbits.

Isolated cases of remote dynamic triggering in Canada detected using cataloged earthquakes combined with a matched-filter approach

USGS Publications Warehouse

Bei, Wang; Harrington, Rebecca M.; Liu, Yajing; Yu, Hongyu; Carey, Alex; van der Elst, Nicholas

2015-01-01

Here we search for dynamically triggered earthquakes in Canada following global main shocks between 2004 and 2014 with MS > 6, depth < 100 km, and estimated peak ground velocity > 0.2 cm/s. We use the Natural Resources Canada (NRCan) earthquake catalog to calculate β statistical values in 1° × 1° bins in 10 day windows before and after the main shocks. The statistical analysis suggests that triggering may occur near Vancouver Island, along the border of the Yukon and Northwest Territories, in western Alberta, western Ontario, and the Charlevoix seismic zone. We also search for triggering in Alberta where denser seismic station coverage renders regional earthquake catalogs with lower completeness thresholds. We find remote triggering in Alberta associated with three main shocks using a matched-filter approach on continuous waveform data. The increased number of local earthquakes following the passage of main shock surface waves suggests local faults may be in a critically stressed state.

Dynamic stresses, Coulomb failure, and remote triggering

USGS Publications Warehouse

Hill, D.P.

2008-01-01

Dynamic stresses associated with crustal surface waves with 15-30-sec periods and peak amplitudes 5 km). The latter is consistent with the observation that extensional or transtensional tectonic regimes are more susceptible to remote triggering by Rayleigh-wave dynamic stresses than compressional or transpressional regimes. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems.

Pulling the Parent Trigger--Forum. "Education Next" Talks with Ben Austin and Michael J. Petrilli

ERIC Educational Resources Information Center

Austin, Ben; Petrilli, Michael J.

2013-01-01

Championed by California-based Parent Revolution, and adopted first by California in early 2010, more than a half-dozen states now have parent trigger laws. The parent trigger, which allows a majority of parents at a low-performing school to vote to seize control from the local district, has been wielded at four California schools. Is the parent…

Ultrasound-enhanced localized chemotherapy of drug-sensitive and multidrug resistant tumors

NASA Astrophysics Data System (ADS)

Rapoport, Natalya Y.; Gao, Zhonggao; Kamaev, Pavel; Christensen, Douglas A.

2006-05-01

A new modality of targeted tumor chemotherapy is based on the drug encapsulation in polymeric nanoparticles followed by a localized release at the tumor site triggered by focused ultrasound. Effect of 1 MHz and 3 MHz unfocused ultrasound applied locally to the tumor on the Doxorubicin (DOX) biodistribution and tumor growth rates was measured for ovarian carcinoma tumors in nu/nu mice. The bioeffects of ultrasound were investigated on the systemic and cellular levels. Growth rates of A2780 ovarian carcinoma tumors were substantially reduced by combining micellar drug delivery with tumor irradiation. Ultrasound effect was not thermal as manifested by intratumoral temperature measurements during sonication. Biodistribution studies showed that ultrasound did not enhance micelle extravasation. Main mechanisms of the ultrasound-enhanced chemotherapy included (i) passive targeting of drug-loaded micelles to the tumor interstitium; (ii) ultrasound-triggered localized drug release from micelles in the tumor volume; (iii) enhanced micelle and drug diffusion through the tumor interstitium; and (iv) ultrasound-triggered cell membrane damage resulting in the enhanced micelle and drug uptake by tumor cells.

Systematic Analysis of Dynamic Earthquake Triggering Using the EarthScope's USArray Data

NASA Astrophysics Data System (ADS)

Cerda, I.; Gonzalez-Huizar, H.; Velasco, A. A.; Kilb, D. L.; Pankow, K. L.

2011-12-01

Advances are continually made in our understanding of the physics governing earthquake triggering, yet many questions remain. Here, we investigate if there exists a minimum dynamic stress threshold (i.e., in amplitude, frequency or both) required to trigger remote earthquakes using data collected by >400 stations in EarthScope's USArray Transportable Array (USArray TA) network, supplemented by data from ~100 local seismic network stations when available. We also assess if remote triggering is enhanced if the orientation of the passing seismic waves aligns favorably with the local stress field and/or orientation of faults in the local triggered region. The uniform spacing of the USArray TA stations across the contiguous USA allows us to examine these types of characteristics of remote triggering within a variety of tectonic provinces, background seismicity rates, and within regions of both documented cases of triggered earthquakes and areas of no known triggered earthquakes. Our work focuses on assessing remote triggering capabilities of two teleseismic megatrust events (Japan M=9.0 2011 and Chile M=8.8 2010) and two large regional events (Baja California M=7.2 2010 and Wells Nevada M=6.0 2008). These events provide a range of seismic wave amplitudes and orientations across the footprint of the USArray TA stations. We use the Antelope software to develop an automated detection algorithm that computes the short-term (1 s) average (STA) to long-term (10 s) average (LTA) ratio, which we apply to 5 Hz high pass filtered data. Using a threshold ratio of 3.5 we apply this algorithm to data spanning ±5 hours from the mainshock's P-wave arrival time. We find that for each of our four mainshocks our algorithm nets, on average, hundreds of detections within the 10 hour time windows. Results suggest the orientation of the passing seismic waves can play a role in the high (or low) number of detections in select regions (e.g., western part of Texas), but in other regions there is no apparent correlation.

Unraveling earthquake stresses: Insights from dynamically triggered and induced earthquakes

NASA Astrophysics Data System (ADS)

Velasco, A. A.; Alfaro-Diaz, R. A.

2017-12-01

Induced seismicity, earthquakes caused by anthropogenic activity, has more than doubled in the last several years resulting from practices related to oil and gas production. Furthermore, large earthquakes have been shown to promote the triggering of other events within two fault lengths (static triggering), due to static stresses caused by physical movement along the fault, and also remotely from the passage of seismic waves (dynamic triggering). Thus, in order to understand the mechanisms for earthquake failure, we investigate regions where natural, induced, and dynamically triggered events occur, and specifically target Oklahoma. We first analyze data from EarthScope's USArray Transportable Array (TA) and local seismic networks implementing an optimized (STA/LTA) detector in order to develop local detection and earthquake catalogs. After we identify triggered events through statistical analysis, and perform a stress analysis to gain insight on the stress-states leading to triggered earthquake failure. We use our observations to determine the role of different transient stresses in contributing to natural and induced seismicity by comparing these stresses to regional stress orientation. We also delineate critically stressed regions of triggered seismicity that may indicate areas susceptible to earthquake hazards associated with sustained fluid injection in provinces of induced seismicity. Anthropogenic injection and extraction activity can alter the stress state and fluid flow within production basins. By analyzing the stress release of these ancient faults caused by dynamic stresses, we may be able to determine if fluids are solely responsible for increased seismic activity in induced regions.

Subgingival Microbial Communities in Leukocyte Adhesion Deficiency and Their Relationship with Local Immunopathology

PubMed Central

Moutsopoulos, Niki M.; Abusleme, Loreto; Greenwell-Wild, Teresa; Dutzan, Nicolas; Paster, Bruce J.; Munson, Peter J.; Fine, Daniel H.; Uzel, Gulbu; Holland, Steven M.

2015-01-01

Leukocyte Adhesion Deficiency I (LAD-I) is a primary immunodeficiency caused by single gene mutations in the CD18 subunit of β2 integrins which result in defective transmigration of neutrophils into the tissues. Affected patients suffer from recurrent life threatening infections and severe oral disease (periodontitis). Microbial communities in the local environment (subgingival plaque) are thought to be the triggers for inflammatory periodontitis, yet little is known regarding the microbial communities associated with LAD-I periodontitis. Here we present the first comprehensive characterization of the subgingival communities in LAD-I, using a 16S rRNA gene-based microarray, and investigate the relationship of this tooth adherent microbiome to the local immunopathology of periodontitis. We show that the LAD subgingival microbiome is distinct from that of health and Localized Aggressive Periodontitits. Select periodontitis-associated species in the LAD microbiome included Parvimonas micra, Porphyromonas endodontalis, Eubacterium brachy and Treponema species. Pseudomonas aeruginosa, a bacterium not typically found in subgingival plaque is detected in LAD-I. We suggest that microbial products from LAD-associated communities may have a role in stimulating the local inflammatory response. We demonstrate that bacterial LPS translocates into the lesions of LAD-periodontitis potentially triggering immunopathology. We also show in in vitro assays with human macrophages and in vivo in animal models that microbial products from LAD-associated subgingival plaque trigger IL-23-related immune responses, which have been shown to dominate in patient lesions. In conclusion, our current study characterizes the subgingival microbial communities in LAD-periodontitis and supports their role as triggers of disease pathogenesis. PMID:25741691

Subgingival microbial communities in Leukocyte Adhesion Deficiency and their relationship with local immunopathology.

PubMed

Moutsopoulos, Niki M; Chalmers, Natalia I; Barb, Jennifer J; Abusleme, Loreto; Greenwell-Wild, Teresa; Dutzan, Nicolas; Paster, Bruce J; Munson, Peter J; Fine, Daniel H; Uzel, Gulbu; Holland, Steven M

2015-03-01

Leukocyte Adhesion Deficiency I (LAD-I) is a primary immunodeficiency caused by single gene mutations in the CD18 subunit of β2 integrins which result in defective transmigration of neutrophils into the tissues. Affected patients suffer from recurrent life threatening infections and severe oral disease (periodontitis). Microbial communities in the local environment (subgingival plaque) are thought to be the triggers for inflammatory periodontitis, yet little is known regarding the microbial communities associated with LAD-I periodontitis. Here we present the first comprehensive characterization of the subgingival communities in LAD-I, using a 16S rRNA gene-based microarray, and investigate the relationship of this tooth adherent microbiome to the local immunopathology of periodontitis. We show that the LAD subgingival microbiome is distinct from that of health and Localized Aggressive Periodontitits. Select periodontitis-associated species in the LAD microbiome included Parvimonas micra, Porphyromonas endodontalis, Eubacterium brachy and Treponema species. Pseudomonas aeruginosa, a bacterium not typically found in subgingival plaque is detected in LAD-I. We suggest that microbial products from LAD-associated communities may have a role in stimulating the local inflammatory response. We demonstrate that bacterial LPS translocates into the lesions of LAD-periodontitis potentially triggering immunopathology. We also show in in vitro assays with human macrophages and in vivo in animal models that microbial products from LAD-associated subgingival plaque trigger IL-23-related immune responses, which have been shown to dominate in patient lesions. In conclusion, our current study characterizes the subgingival microbial communities in LAD-periodontitis and supports their role as triggers of disease pathogenesis.

Global and local "teachable moments": The role of Nobel Prize and national pride.

PubMed

Baram-Tsabari, Ayelet; Segev, Elad

2018-05-01

This study examined to what extent Nobel Prize announcements and awards trigger global and local searches or "teachable moments" related to the laureates and their discoveries. We examined the longitudinal trends in Google searches for the names and discoveries of Nobel laureates from 2012 to 2017. The findings show that Nobel Prize events clearly trigger more searches for laureates, but also for their respective discoveries. We suggest that fascination with the Nobel prize creates a teachable moment not only for the underlying science, but also about the nature of science. Locality also emerged as playing a significant role in intensifying interest.

Detection of high-risk atherosclerotic lesions by time-resolved fluorescence spectroscopy based on the Laguerre deconvolution technique

NASA Astrophysics Data System (ADS)

Jo, J. A.; Fang, Q.; Papaioannou, T.; Qiao, J. H.; Fishbein, M. C.; Beseth, B.; Dorafshar, A. H.; Reil, T.; Baker, D.; Freischlag, J.; Marcu, L.

2006-02-01

This study introduces new methods of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) data analysis for tissue characterization. These analytical methods were applied for the detection of atherosclerotic vulnerable plaques. Upon pulsed nitrogen laser (337 nm, 1 ns) excitation, TR-LIFS measurements were obtained from carotid atherosclerotic plaque specimens (57 endarteroctomy patients) at 492 distinct areas. The emission was both spectrally- (360-600 nm range at 5 nm interval) and temporally- (0.3 ns resolution) resolved using a prototype clinically compatible fiber-optic catheter TR-LIFS apparatus. The TR-LIFS measurements were subsequently analyzed using a standard multiexponential deconvolution and a recently introduced Laguerre deconvolution technique. Based on their histopathology, the lesions were classified as early (thin intima), fibrotic (collagen-rich intima), and high-risk (thin cap over necrotic core and/or inflamed intima). Stepwise linear discriminant analysis (SLDA) was applied for lesion classification. Normalized spectral intensity values and Laguerre expansion coefficients (LEC) at discrete emission wavelengths (390, 450, 500 and 550 nm) were used as features for classification. The Laguerre based SLDA classifier provided discrimination of high-risk lesions with high sensitivity (SE>81%) and specificity (SP>95%). Based on these findings, we believe that TR-LIFS information derived from the Laguerre expansion coefficients can provide a valuable additional dimension for the diagnosis of high-risk vulnerable atherosclerotic plaques.

Elevated tumour necrosis factor-alpha was associated with intima thickening in obese children.

PubMed

Bo, Luo; Yi-Can, Yang; Qing, Zhou; Xiao-Hui, Wu; Ke, Huang; Chao-Chun, Zou

2017-04-01

This study investigated the relationship between intima-media thickness (IMT) and immune parameters in obese children from five to 16 years of age. We enrolled 185 obese children with a mean age of 10.65 ± 2.10 years and 211 controls with a mean age of 10.32 ± 1.81 years. Glycometabolism, lipid metabolism, sex hormones, immune indices and carotid IMT were measured. Serum interleukin (IL)-6, IL-10, tumour necrosis factor (TNF)-alpha, white blood cells and common and internal carotid artery IMTs in the obese group were higher than those in the control group (p < 0.05, respectively). Bivariate correlation analysis showed that the common carotid arterial IMT was positively correlated with alanine aminotransferase, triglyceride, uric acid, apolipoprotein B, IL-6, IL-10, TNF-alpha, follicle-stimulating hormone and testosterone. Internal carotid artery IMT was positively correlated with alanine aminotransferase and follicle-stimulating hormone. Both common and internal carotid artery IMTs were inversely correlated with apolipoprotein A1 (p < 0.05, respectively). Stepwise multiple regression analysis showed that testosterone, alanine aminotransferase and TNF-alpha were the independent determinants of common carotid arterial IMT. Tumour necrosis factor-alpha, alanine aminotransferase and testosterone were associated with intima thickening in the early life in obese children and may increase later risks of premature atherogenicity and adult cardio-cerebrovascular diseases. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Feasibility of two-dimensional speckle tracking in evaluation of arterial stiffness: Comparison with pulse wave velocity and conventional sonographic markers of atherosclerosis.

PubMed

Podgórski, Michał; Grzelak, Piotr; Kaczmarska, Magdalena; Polguj, Michał; Łukaszewski, Maciej; Stefańczyk, Ludomir

2018-02-01

Objective Arterial stiffening is an early marker of atherosclerosis that has a prognostic value for cardiovascular morbidity and mortality. Although many markers of arterial hardening have been proposed, the search is on for newer, more user-friendly and reliable surrogates. One such potential candidate has emerged from cardiology, the speckle-tracking technique. The aim of this study was to evaluate the feasibility of the two-dimensional speckle tracking for the evaluation of arterial wall stiffness in comparison with standard stiffness parameters. Methods Carotid ultrasound and applanation tonometry were performed in 188 patients with no cardiovascular risk factors. The following parameters were then evaluated: the intima-media complex thickness, distensibility coefficient, β-stiffness index, circumferential strain/strain rate, and pulse wave velocity and augmentation index. These variables were compared with each other and with patient age, and their reliability was assessed with Bland-Altman plots. Results Strain parameters derived from two-dimensional speckle tracking and intima-media complex thickness correlated better with age and pulse wave velocity than standard makers of arterial stiffness. Moreover, the reliability of these measurements was significantly higher than conventional surrogates. Conclusions Two-dimensional speckle tracing is a reliable method for the evaluation of arterial stiffness. Therefore, together with intima-media complex thickness measurement, it offers great potential in clinical practice as an early marker of atherosclerosis.

Coronary atherosclerosis burden is not advanced in patients with β-thalassemia despite premature extracardiac atherosclerosis: a coronary artery calcium score and carotid intima-media thickness study.

PubMed

Hahalis, George; Zacharioglou, Evangelia; Xanthopoulou, Ioanna; Koniari, Ioanna; Kalogeropoulou, Chistina; Tsota, Irene; Rigopoulou, Aspasia; Diamantopoulos, Athanasios; Gkizas, Vasilios; Davlouros, Periklis; Akinosoglou, Karolina; Leopoulou, Marianna; Gogos, Charalampos; Alexopoulos, Dimitrios

2016-02-01

Thalassemic patients demonstrate an increased rate of extracardiac vascular complications and increased carotid wall intima-media thickness (cIMT), but very low prevalence of coronary artery disease (CAD). We investigated the atheroma burden by assessing the coronary artery calcium (CAC) and cIMT in these patients. We examined 37 patients with β-thalassemia and 150 healthy control volunteers with multi-detector computer tomography (CT) and ultrasonography to determine CAC score and cIMT, respectively. Propensity score matching (C-statistic: 0.88; 95% CI: 0.83-0.93) resulted in 27 pairs of patients; severe CAC was observed in 2 (7.4%) and 0 of β-thalassemia patients and healthy volunteers respectively (P = 0.5). Median calcium score was 0 (0-0) in β-thalassemia patients and 0 (0-4) in healthy volunteers (P = 0.8). Median intima-media thickness was higher in β-thalassemia patients compared to control group [0.45 (0.06-0.65) vs. 0.062 (0.054-0.086); P = 0.04]. Patients with β-thalassemia in comparison with healthy control subjects exhibit similar CAC score and increased cIMT. Our findings indicate a disparate rate of progression of atherosclerosis between coronary and extracardiac arteries in these patients lending support to the epidemiological evidence.

Glycated hemoglobin correlates with arterial stiffness and endothelial dysfunction in patients with resistant hypertension and uncontrolled diabetes mellitus.

PubMed

Moreno, Beatriz; de Faria, Ana Paula; Ritter, Alessandra Mileni Versuti; Yugar, Lara Buonalumi Tacito; Ferreira-Melo, Silvia Elaine; Amorim, Rivadavio; Modolo, Rodrigo; Fattori, André; Yugar-Toledo, Juan Carlos; Coca, Antonio; Moreno, Heitor

2018-05-01

This study aimed to evaluate the effects of glycated hemoglobin (HbA 1c ) on flow-mediated dilation, intima-media thickness, pulse wave velocity, and left ventricular mass index in patients with resistant hypertension (RHTN) comparing RHTN-controlled diabetes mellitus and RHTN-uncontrolled type 2 diabetes mellitus. Two groups were formed: HbA 1c <7.0% (RHTN-controlled diabetes mellitus: n = 98) and HbA 1c ≥7.0% (RHTN-uncontrolled diabetes mellitus: n = 122). Intima-media thickness and flow-mediated dilation were measured by high-resolution ultrasound, left ventricular mass index by echocardiography, and arterial stiffness by carotid-femoral pulse wave velocity. No differences in blood pressure levels were found between the groups but body mass index was higher in patients with RHTN-uncontrolled diabetes mellitus. Endothelial dysfunction and arterial stiffness were worse in patients with RHTN-uncontrolled diabetes mellitus. Intima-media thickness and left ventricular mass index measurements were similar between the groups. After adjustments, multiple linear regression analyses showed that HbA 1c was an independent predictor of flow-mediated dilation and pulse wave velocity in all patients with RHTN. In conclusion, HbA 1c may predict the grade of arterial stiffness and endothelial dysfunction in patients with RHTN, and superimposed uncontrolled diabetes mellitus implicates further impairment of vascular function. ©2018 Wiley Periodicals, Inc.

Histopathological Differences Between the Anterior and Posterior Brain Arteries as a Function of Aging.

PubMed

Roth, William; Morgello, Susan; Goldman, James; Mohr, Jay P; Elkind, Mitchell S V; Marshall, Randolph S; Gutierrez, Jose

2017-03-01

We tested the hypothesis that posterior brain arteries differ pathologically from anterior brain arteries and that this difference varies with age. Brain large arteries from 194 autopsied individuals (mean age 56±17 years, 63% men, 25% nonwhite, 17% with brain infarcts) were analyzed to obtain the areas of arterial layers and lumen as well as the relative content of elastin, collagen, and amyloid. Visual rating was used to determine the prevalence of atheroma, calcification, vasa vasorum , pattern of intima thickening, and internal elastic lamina gaps. We used multilevel models adjusting for age, sex, ethnicity, vascular risk factors, artery type and location, and multiple comparisons. Of 1362 large artery segments, 5% had vasa vasorum, 5% had calcifications, 15% had concentric intimal thickening, and 11% had atheromas. Posterior brain arteries had thinner walls, less elastin, and more concentric intima thickening than anterior brain arteries. Compared to anterior brain arteries, the basilar artery had higher arterial area encircled by the internal elastic lamina, whereas the vertebral arteries had higher prevalence of elastin loss, concentric intima thickening, and nonatherosclerotic stenosis. In younger individuals, vertebral artery calcifications were more likely than calcification in anterior brain arteries, but this difference attenuated with age. Posterior brain arteries differ pathologically from anterior brain arteries in the degree of wall thickening, elastin loss, and concentric intimal thickening. © 2017 American Heart Association, Inc.

Design and Rationale of the Intima-Medial Thickness Sub-Study of the PreventIon of CArdiovascular Events in iSchemic Stroke Patients with High Risk of Cerebral hemOrrhage (PICASSO-IMT) Study.

PubMed

Seo, Woo-Keun; Kim, Yong Jae; Lee, Juneyoung; Kwon, Sun U

2017-09-01

Atherosclerosis is one of the main mechanisms of stroke and cardiovascular diseases and is associated with increased risk of recurrent stroke and cardiovascular events. Intima-medial thickness (IMT) is a well-known surrogate marker of atherosclerosis and has been used to predict stroke and cardiovascular events. However, the clinical significance of IMT and IMT change in stroke has not been investigated in well-designed studies. The PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage-Intima-Media Thickness (PICASSO-IMT) sub-study is designed to investigate the effects of cilostazol, probucol, or both on IMT in patients with stroke. PICASSO-IMT is a prospective sub-study of the PICASSO study designed to measure IMT and plaque score at 1, 13, 25, 37, and 49 months after randomization. The primary outcome is the change in mean carotid IMT, which is defined as the mean of the far-wall IMTs of the right and left common carotid arteries, between baseline and 13 months after randomization. PICASSO-IMT will provide the largest IMT data set in a stroke population and will provide valuable information about the clinical significance of IMT in patients with ischemic stroke. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Mechanical properties of human atherosclerotic intima tissue.

PubMed

Akyildiz, Ali C; Speelman, Lambert; Gijsen, Frank J H

2014-03-03

Progression and rupture of atherosclerotic plaques in coronary and carotid arteries are the key processes underlying myocardial infarctions and strokes. Biomechanical stress analyses to compute mechanical stresses in a plaque can potentially be used to assess plaque vulnerability. The stress analyses strongly rely on accurate representation of the mechanical properties of the plaque components. In this review, the composition of intima tissue and how this changes during plaque development is discussed from a mechanical perspective. The plaque classification scheme of the American Heart Association is reviewed and plaques originating from different vascular territories are compared. Thereafter, an overview of the experimental studies on tensile and compressive plaque intima properties are presented and the results are linked to the pathology of atherosclerotic plaques. This overview revealed a considerable variation within studies, and an enormous dispersion between studies. Finally, the implications of the dispersion in experimental data on the clinical applications of biomechanical plaque modeling are presented. Suggestions are made on mechanical testing protocol for plaque tissue and on using a standardized plaque classification scheme. This review identifies the current status of knowledge on plaque mechanical properties and the future steps required for a better understanding of the plaque type specific material properties. With this understanding, biomechanical plaque modeling may eventually provide essential support for clinical plaque risk stratification. Copyright © 2014 Elsevier Ltd. All rights reserved.

Atheroprotection through SYK inhibition fails in established disease when local macrophage proliferation dominates lesion progression.

PubMed

Lindau, Alexandra; Härdtner, Carmen; Hergeth, Sonja P; Blanz, Kelly Daryll; Dufner, Bianca; Hoppe, Natalie; Anto-Michel, Nathaly; Kornemann, Jan; Zou, Jiadai; Gerhardt, Louisa M S; Heidt, Timo; Willecke, Florian; Geis, Serjosha; Stachon, Peter; Wolf, Dennis; Libby, Peter; Swirski, Filip K; Robbins, Clinton S; McPheat, William; Hawley, Shaun; Braddock, Martin; Gilsbach, Ralf; Hein, Lutz; von zur Mühlen, Constantin; Bode, Christoph; Zirlik, Andreas; Hilgendorf, Ingo

2016-03-01

Macrophages in the arterial intima sustain chronic inflammation during atherogenesis. Under hypercholesterolemic conditions murine Ly6C(high) monocytes surge in the blood and spleen, infiltrate nascent atherosclerotic plaques, and differentiate into macrophages that proliferate locally as disease progresses. Spleen tyrosine kinase (SYK) may participate in downstream signaling of various receptors that mediate these processes. We tested the effect of the SYK inhibitor fostamatinib on hypercholesterolemia-associated myelopoiesis and plaque formation in Apoe(-/-) mice during early and established atherosclerosis. Mice consuming a high cholesterol diet supplemented with fostamatinib for 8 weeks developed less atherosclerosis. Histologic and flow cytometric analysis of aortic tissue showed that fostamatinib reduced the content of Ly6C(high) monocytes and macrophages. SYK inhibition limited Ly6C(high) monocytosis through interference with GM-CSF/IL-3 stimulated myelopoiesis, attenuated cell adhesion to the intimal surface, and blocked M-CSF stimulated monocyte to macrophage differentiation. In Apoe(-/-) mice with established atherosclerosis, however, fostamatinib treatment did not limit macrophage accumulation or lesion progression despite a significant reduction in blood monocyte counts, as lesional macrophages continued to proliferate. Thus, inhibition of hypercholesterolemia-associated monocytosis, monocyte infiltration, and differentiation by SYK antagonism attenuates early atherogenesis but not established disease when local macrophage proliferation dominates lesion progression.

PLK4 trans-Autoactivation Controls Centriole Biogenesis in Space.

PubMed

Lopes, Carla A M; Jana, Swadhin Chandra; Cunha-Ferreira, Inês; Zitouni, Sihem; Bento, Inês; Duarte, Paulo; Gilberto, Samuel; Freixo, Francisco; Guerrero, Adán; Francia, Maria; Lince-Faria, Mariana; Carneiro, Jorge; Bettencourt-Dias, Mónica

2015-10-26

Centrioles are essential for cilia and centrosome assembly. In centriole-containing cells, centrioles always form juxtaposed to pre-existing ones, motivating a century-old debate on centriole biogenesis control. Here, we show that trans-autoactivation of Polo-like kinase 4 (PLK4), the trigger of centriole biogenesis, is a critical event in the spatial control of that process. We demonstrate that centrioles promote PLK4 activation through its recruitment and local accumulation. Though centriole removal reduces the proportion of active PLK4, this is rescued by concentrating PLK4 to the peroxisome lumen. Moreover, while mild overexpression of PLK4 only triggers centriole amplification at the existing centriole, higher PLK4 levels trigger both centriolar and cytoplasmatic (de novo) biogenesis. Hence, centrioles promote their assembly locally and disfavor de novo synthesis. Similar mechanisms enforcing the local concentration and/or activity of other centriole components are likely to contribute to the spatial control of centriole biogenesis under physiological conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

Global Search of Triggered Tectonic Tremor

NASA Astrophysics Data System (ADS)

Peng, Z.; Aiken, C.; Chao, K.; Gonzalez-Huizar, H.; Wang, B.; Ojha, L.; Yang, H.

2013-05-01

Deep tectonic tremor has been observed at major plate-boundary faults around the Pacific Rim. While regular or ambient tremor occurs spontaneously or accompanies slow-slip events, tremor could be also triggered by large distant earthquakes and solid earth tides. Because triggered tremor occurs on the same fault patches as ambient tremor and is relatively easy to identify, a systematic global search of triggered tremor could help to identify the physical mechanisms and necessary conditions for tremor generation. Here we conduct a global search of tremor triggered by large teleseismic earthquakes. We mainly focus on major faults with significant strain accumulations where no tremor has been reported before. These includes subduction zones in Central and South America, strike-slip faults around the Caribbean plate, the Queen Charlotte-Fairweather fault system and the Denali fault in the western Canada and Alaska, the Sumatra-Java subduction zone, the Himalaya frontal thrust faults, as well as major strike-slip faults around Tibet. In each region, we first compute the predicted dynamic stresses σd from global earthquakes with magnitude>=5.0 in the past 20 years, and select events with σd > 1 kPa. Next, we download seismic data recorded by stations from local or global seismic networks, and identify triggered tremor as a high-frequency non-impulsive signal that is in phase with the large-amplitude teleseismic waves. In cases where station distributions are dense enough, we also locate tremor based on the standard envelope cross-correlation techniques. Finally, we calculate the triggering potential for the Love and Rayleigh waves with the local fault orientation and surface-wave incident angles. So far we have found several new places that are capable of generating triggered tremor. We will summarize these observations and discuss their implications on physical mechanisms of tremor and remote triggering.

The NA62 trigger system

NASA Astrophysics Data System (ADS)

Krivda, M.; NA62 Collaboration

2013-08-01

The main aim of the NA62 experiment (NA62 Technical Design Report, [1]) is to study ultra-rare Kaon decays. In order to select rare events over the overwhelming background, central systems with high-performance, high bandwidth, flexibility and configurability are necessary, that minimize dead time while maximizing data collection reliability. The NA62 experiment consists of 12 sub-detector systems and several trigger and control systems, for a total channel count of less than 100,000. The GigaTracKer (GTK) has the largest number of channels (54,000), and the Liquid Krypton (LKr) calorimeter shares with it the largest raw data rate (19 GB/s). The NA62 trigger system works with 3 trigger levels. The first trigger level is based on a hardware central trigger unit, so-called L0 Trigger Processor (L0TP), and Local Trigger Units (LTU), which are all located in the experimental cavern. Other two trigger levels are based on software, and done with a computer farm located on surface. The L0TP receives information from triggering sub-detectors asynchronously via Ethernet; it processes the information, and then transmits a final trigger decision synchronously to each sub-detector through the Trigger and Timing Control (TTC) system. The interface between L0TP and the TTC system, which is used for trigger and clock distribution, is provided by the Local Trigger Unit board (LTU). The LTU can work in two modes: global and stand-alone. In the global mode, the LTU provides an interface between L0TP and TTC system. In the stand-alone mode, the LTU can fully emulate L0TP and so provides an independent way for each sub-detector for testing or calibration purposes. In addition to the emulation functionality, a further functionality is implemented that allows to synchronize the clock of the LTU with the L0TP and the TTC system. For testing and debugging purposes, a Snap Shot Memory (SSM) interface is implemented, that can work both in an input or an output mode. The trigger rates will be permanently monitored by reading counters at regular intervals. This paper describes the overall NA62 trigger system focusing on the setup for the dry and technical runs in 2012.

Automated high-performance cIMT measurement techniques using patented AtheroEdge™: a screening and home monitoring system.

PubMed

Molinari, Filippo; Meiburger, Kristen M; Suri, Jasjit

2011-01-01

The evaluation of the carotid artery wall is fundamental for the assessment of cardiovascular risk. This paper presents the general architecture of an automatic strategy, which segments the lumen-intima and media-adventitia borders, classified under a class of Patented AtheroEdge™ systems (Global Biomedical Technologies, Inc, CA, USA). Guidelines to produce accurate and repeatable measurements of the intima-media thickness are provided and the problem of the different distance metrics one can adopt is confronted. We compared the results of a completely automatic algorithm that we developed with those of a semi-automatic algorithm, and showed final segmentation results for both techniques. The overall rationale is to provide user-independent high-performance techniques suitable for screening and remote monitoring.

Association between air pollution and coronary artery calcification within six metropolitan areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): a longitudinal cohort study

PubMed Central

Kaufman, Joel D; Adar, Sara D; Barr, R Graham; Budoff, Matthew; Burke, Gregory L; Curl, Cynthia L; Daviglus, Martha L; Roux, Ana V Diez; Gassett, Amanda J; Jacobs, David R; Kronmal, Richard; Larson, Timothy V; Navas-Acien, Ana; Olives, Casey; Sampson, Paul D; Sheppard, Lianne; Siscovick, David S; Stein, James H; Szpiro, Adam A; Watson, Karol E

2016-01-01

Summary Background Long-term exposure to fine particulate matter less than 2·5 μm in diameter (PM2·5) and traffic-related air pollutant concentrations are associated with cardiovascular risk. The disease process underlying these associations remains uncertain. We aim to assess association between long-term exposure to ambient air pollution and progression of coronary artery calcium and common carotid artery intima-media thickness. Methods In this prospective 10-year cohort study, we repeatedly measured coronary artery calcium by CT in 6795 participants aged 45–84 years enrolled in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) in six metropolitan areas in the USA. Repeated scans were done for nearly all participants between 2002 and 2005, for a subset of participants between 2005 and 2007, and for half of all participants between 2010 and 2012. Common carotid artery intima-media thickness was measured by ultrasound in all participants at baseline and in 2010–12 for 3459 participants. Residence-specific spatio-temporal pollution concentration models, incorporating community-specific measurements, agency monitoring data, and geographical predictors, estimated concentrations of PM2·5 and nitrogen oxides (NOX) between 1999 and 2012. The primary aim was to examine the association between both progression of coronary artery calcium and mean carotid artery intima-media thickness and long-term exposure to ambient air pollutant concentrations (PM2·5, NOX, and black carbon) between examinations and within the six metropolitan areas, adjusting for baseline age, sex, ethnicity, socioeconomic characteristics, cardiovascular risk factors, site, and CT scanner technology. Findings In this population, coronary calcium increased on average by 24 Agatston units per year (SD 58), and intima-media thickness by 12 μm per year (10), before adjusting for risk factors or air pollutant exposures. Participant-specific pollutant concentrations averaged over the years 2000–10 ranged from 9·2–22·6 μg PM2·5/m3 and 7·2–139·2 parts per billion (ppb) NOX. For each 5 μg PM2·5/m3 increase, coronary calcium progressed by 4·1 Agatston units per year (95% CI 1·4–6·8) and for each 40 ppb NOX coronary calcium progressed by 4·8 Agatston units per year (0·9–8·7). Pollutant exposures were not associated with intima-media thickness change. The estimate for the effect of a 5 μg/m3 higher long-term exposure to PM2·5 in intima-media thickness was −0·9 μm per year (95% CI −3·0 to 1·3). For 40 ppb higher NOX, the estimate was 0·2 μm per year (−1·9 to 2·4). Interpretation Increased concentrations of PM2·5 and traffc-related air pollution within metropolitan areas, in ranges commonly encountered worldwide, are associated with progression in coronary calcification, consistent with acceleration of atherosclerosis. This study supports the case for global efforts of pollution reduction in prevention of cardiovascular diseases. Funding US Environmental Protection Agency and US National Institutes of Health. PMID:27233746

Efficient generation of cavitation bubbles and reactive oxygen species using triggered high-intensity focused ultrasound sequence for sonodynamic treatment

NASA Astrophysics Data System (ADS)

Yasuda, Jun; Yoshizawa, Shin; Umemura, Shin-ichiro

2016-07-01

Sonodynamic treatment is a method of treating cancer using reactive oxygen species (ROS) generated by cavitation bubbles in collaboration with a sonosensitizer at a target tissue. In this treatment method, both localized ROS generation and ROS generation with high efficiency are important. In this study, a triggered high-intensity focused ultrasound (HIFU) sequence, which consists of a short, extremely high intensity pulse immediately followed by a long, moderate-intensity burst, was employed for the efficient generation of ROS. In experiments, a solution sealed in a chamber was exposed to a triggered HIFU sequence. Then, the distribution of generated ROS was observed by the luminol reaction, and the amount of generated ROS was quantified using KI method. As a result, the localized ROS generation was demonstrated by light emission from the luminol reaction. Moreover, it was demonstrated that the triggered HIFU sequence has higher efficiency of ROS generation by both the KI method and the luminol reaction emission.

Triggering processes of microseismic events associated with water injection in Okuaizu Geothermal Field, Japan

NASA Astrophysics Data System (ADS)

Okamoto, Kyosuke; Yi, Li; Asanuma, Hiroshi; Okabe, Takashi; Abe, Yasuyuki; Tsuzuki, Masatoshi

2018-02-01

A continuous water injection test was conducted to halt the reduction in steam production in the Okuaizu Geothermal Field, Japan. Understanding the factors triggering microseismicity associated with water injection is essential to ensuring effective steam production. We identified possible triggering processes by applying methods based on microseismic monitoring, including a new method to determine the presence of water in local fractures using scattered P-waves. We found that the evolving microseismicity near the injection point could be explained by a diffusion process and/or water migration. We also found that local microseismicity on a remote fault was likely activated by stress fluctuations resulting from changes in the injection rate. A mediator of this fluctuation might be water remaining in the fracture zone. After the injection was terminated, microseismicity possibly associated with the phase transition of the liquid was found. We conclude that a variety of triggering processes associated with water injection may exist.[Figure not available: see fulltext.

Remotely triggered microearthquakes and tremor in central California following the 2010 Mw 8.8 Chile earthquake

USGS Publications Warehouse

Peng, Zhigang; Hill, David P.; Shelly, David R.; Aiken, Chastity

2010-01-01

We examine remotely triggered microearthquakes and tectonic tremor in central California following the 2010 Mw 8.8 Chile earthquake. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest earthquake (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield-Cholame section of the San Andreas Fault (SAF). The locally triggered tremor bursts are partially masked at lower frequencies by the regionally triggered earthquake signals from Coso, but can be identified by applying high-pass or matched filters. Both triggered tremor along the SAF and the Ml 3.5 earthquake in Coso are consistent with frictional failure at different depths on critically-stressed faults under the Coulomb failure criteria. The triggered tremor, however, appears to be more phase-correlated with the surface waves than the triggered earthquakes, likely reflecting differences in constitutive properties between the brittle, seismogenic crust and the underlying lower crust.

Validation of the Carotid Intima-Media Thickness Variability: Can Manual Segmentations Be Trusted as Ground Truth?

PubMed

Meiburger, Kristen M; Molinari, Filippo; Wong, Justin; Aguilar, Luis; Gallo, Diego; Steinman, David A; Morbiducci, Umberto

2016-07-01

The common carotid artery intima-media thickness (IMT) is widely accepted and used as an indicator of atherosclerosis. Recent studies, however, have found that the irregularity of the IMT along the carotid artery wall has a stronger correlation with atherosclerosis than the IMT itself. We set out to validate IMT variability (IMTV), a parameter defined to assess IMT irregularities along the wall. In particular, we analyzed whether or not manual segmentations of the lumen-intima and media-adventitia can be considered reliable in calculation of the IMTV parameter. To do this, we used a total of 60 simulated ultrasound images with a priori IMT and IMTV values. The images, simulated using the Fast And Mechanistic Ultrasound Simulation software, presented five different morphologies, four nominal IMT values and three different levels of variability along the carotid artery wall (no variability, small variability and large variability). Three experts traced the lumen-intima (LI) and media-adventitia (MA) profiles, and two automated algorithms were employed to obtain the LI and MA profiles. One expert also re-traced the LI and MA profiles to test intra-reader variability. The average IMTV measurements of the profiles used to simulate the longitudinal B-mode images were 0.002 ± 0.002, 0.149 ± 0.035 and 0.286 ± 0.068 mm for the cases of no variability, small variability and large variability, respectively. The IMTV measurements of one of the automated algorithms were statistically similar (p > 0.05, Wilcoxon signed rank) when considering small and large variability, but non-significant when considering no variability (p < 0.05, Wilcoxon signed rank). The second automated algorithm resulted in statistically similar values in the small variability case. Two readers' manual tracings, however, produced IMTV measurements with a statistically significant difference considering all three variability levels, whereas the third reader found a statistically significant difference in both the no variability and large variability cases. Moreover, the error range between the reader and automatic IMTV values was approximately 0.15 mm, which is on the same order of small IMTV values, indicating that manual and automatic IMTV readings should be not used interchangeably in clinical practice. On the basis of our findings, we conclude that expert manual tracings should not be considered reliable in IMTV measurement and, therefore, should not be trusted as ground truth. On the other hand, our automated algorithm was found to be more reliable, indicating how automated techniques could therefore foster analysis of the carotid artery intima-media thickness irregularity. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Acute exacerbation of idiopathic pulmonary fibrosis triggered by Aspergillus empyema.

PubMed

Suzuki, Atsushi; Kimura, Tomoki; Kataoka, Kensuke; Matsuda, Toshiaki; Yokoyama, Toshiki; Mori, Yuta; Kondoh, Yasuhiro

2018-01-01

Acute exacerbation (AE) is a severe and life-threatening complication of idiopathic pulmonary fibrosis (IPF). In 2016, the definition and diagnostic criteria for AE-IPF were updated by an international working group. The new definition includes any acute, clinically significant respiratory deterioration (both idiopathic and triggered events) characterized by evidence of new widespread alveolar abnormality in patients with IPF. There are no currently proven beneficial management strategies for idiopathic and triggered AE-IPF. This is the first report describing AE-IPF triggered by Aspergillus empyema, which was improved by a combination of corticosteroid, systemic antifungal therapy, local antifungal therapy, and additional pharmacological therapies. Future research may reveal optimal strategies for both idiopathic and triggered AE-IPF.

Estimation of prenatal aorta intima-media thickness from ultrasound examination

NASA Astrophysics Data System (ADS)

Veronese, E.; Tarroni, G.; Visentin, S.; Cosmi, E.; Linguraru, M. G.; Grisan, E.

2014-10-01

Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and children, in recent years the measurement of abdominal and carotid artery thickness has gained a growing appeal. Nevertheless, no computer aided method has been proposed for the analysis of prenatal vessels from ultrasound data, yet. To date, these measurements are being performed manually on ultrasound fetal images by skilled practitioners. The aim of the presented study is to introduce an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from routine third trimester ultrasonographic fetal data. The algorithm locates the aorta, then segments it and, by modeling the arterial wall longitudinal sections by means of a gaussian mixture, derives a set of measures of the aorta diameter (aDiam) and of the intima-media thickness (aIMT). After estimating the cardiac cycle, the mean diameter and the aIMT at the end-diastole phase are computed. Considering the aIMT value for each subject, the correlation between automatic and manual end-diastolic aIMT measurements is 0.91 in a range of values 0.44-1.10 mm, corresponding to both normal and pathological conditions. The automatic system yields a mean relative error of 19%, that is similar to the intra-observer variability (14%) and much lower that the inter-observer variability (42%). The correlation between manual and automatic measurements and the small error confirm the ability of the proposed system to reliably estimate aIMT values in prenatal ultrasound sequences, reducing measurement variability and suggesting that it can be used for an automatic assessment of aIMT. Preliminary results have been presented in E Veronese, E Cosmi, S Visentin, E Grisan: 'Semiautomatic estimation of fetal aorta intima-media thickness from ultrasound examination', MICCAI Workshop on Perinatal and Paediatric Imaging: PaPI 2012.

Childhood Age and Associations Between Childhood Metabolic Syndrome and Adult Risk for Metabolic Syndrome, Type 2 Diabetes Mellitus and Carotid Intima Media Thickness: The International Childhood Cardiovascular Cohort Consortium.

PubMed

Koskinen, Juha; Magnussen, Costan G; Sinaiko, Alan; Woo, Jessica; Urbina, Elaine; Jacobs, David R; Steinberger, Julia; Prineas, Ronald; Sabin, Matthew A; Burns, Trudy; Berenson, Gerald; Bazzano, Lydia; Venn, Alison; Viikari, Jorma S A; Hutri-Kähönen, Nina; Raitakari, Olli; Dwyer, Terence; Juonala, Markus

2017-08-16

There is paucity of knowledge concerning the specific age in youth when the associations of metabolic syndrome (MetS) begin to be operative. Thus, we investigated the relation of age to the associations of childhood MetS with adult MetS, type 2 diabetes mellitus and high carotid intima-media thickness. Five thousand eight-hundred three participants were analyzed in 4 cohort studies (Cardiovascular Risk in Young Finns, Bogalusa Heart Study, Princeton Lipid Research Study, Insulin Study). International cutoffs and previously used 75th percentile cutoffs were used for children to define MetS and its components. Mean follow-up period was 22.3 years. Logistic regression was used to calculate risk ratios and 95% confidence intervals. Childhood MetS and overweight were associated with over 2.4-fold risk for adult MetS from the age of 5 years onward. Risk for type 2 diabetes mellitus was increased from the age of 8 (risk ratio, 2.6-4.1; 95% confidence interval, 1.35-6.76 and 1.12-7.24, respectively) onward for the 2 childhood MetS criteria based on international cut-off values and for childhood overweight. Risk for high carotid intima-media thickness was significant at ages 11 to 18 years in relation to childhood MetS or overweight (risk ratio, 2.44-4.22; 95% confidence interval, 1.55-3.55 and 2.55-5.66, respectively). Continuous childhood MetS score was associated with adult MetS from the age of 5, with type 2 diabetes mellitus from the age of 14 and with high carotid intima-media thickness from the age of 11 years onward. Adult MetS was predicted by MetS in childhood beginning at age 5. However, adult type 2 diabetes mellitus and subclinical atherosclerosis were not predicted by childhood data until after age 8. Body mass index measurement alone at the same age points provided similar findings. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Dry needling — peripheral and central considerations

PubMed Central

Dommerholt, Jan

2011-01-01

Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture. PMID:23115475

The Absence of Remotely Triggered Seismicity in Japan from 1997 to 2002

NASA Astrophysics Data System (ADS)

Wakefield, R. H.; Brodsky, E. E.

2003-12-01

Observations of increased seismicity following the Landers, Hector Mine, Izmit, and the Denali, earthquakes suggests remote seismic triggering occurs in geothermal locations as far as 3150 km. This study attempts to determine if the same effects occur in Japan, a geothermal region of high seismicity. For the period of 1997 to 2002, we searched for significant increases in the seismicity levels following earthquakes with Mw >= 6.5 at distances larger than conventionally associated with aftershocks. Additionally, we examined available waveform data in order to detect uncataloged events hidden by the coda of the mainshock. Five events had associated waveform data: March 24, 2001 Geiyo, Mw = 6.8; March 28, 2000 Volcano Islands, Mw = 7.6; July 30, 2000 Honshu, Mw = 6.5; October 6, 2000 Tottori, Mw = 6.7; and the January 28, 1999 Kuril Islands, Mw = 6.8 earthquake. Located 260 km from the Geiyo epicenter, station TKO recorded one possible triggered event within 65 km during the hour following the mainshock. However, the TKO data contains many anomalous spikes, and we are not confident the record is clear enough to differentiate small local events from noise. An ambiguous, two-day, regional seismicity increase followed the Volcano Islands event. We interpret the swarm associated with the signal as coincidental because no similar swarms occurred at the same location following Tottori or Geiyo, both of which had an order of magnitude larger shaking. Both waveforms and cataloged events indicate no triggering occurred following the Honshu, Tottori and Kuril Islands mainshocks. We do not interpret the one indefinite local event recorded by TKO as evidence for mid range dynamic triggering, implying that the 2.5 cm/s shaking at TKO did not exceed the local triggering threshold. Additionally, the lack of triggering following Honshu, Tottori, and Kuril Islands suggests that the 1, 2.5 and 2.6 cm/s shaking at distances of 182, 238, and 267 km, respectively, creates lower bounds for the dynamic triggering thresholds at the respective locations. This assumes the bound is frequency independent. In none of the cases were thresholds exceeded over a large enough region or by large enough amplitude to produce a statistically significant increase in the cataloged rate of seismicity during the period from 1997 to 2002. All previously documented examples of triggering have occurred following shallow earthquakes with Mw > 7. With the exception of Volcano Islands, all of the events of this study have Mw < 7, and have no triggering associated with them. This suggests two possibilities: either events with Mw > 7 are required to produce sufficient shaking to trigger seismicity, or Japan is less susceptible to triggering than the western US or Greece. We assume that the depth of the Volcano Islands earthquake prohibits any substantial surface shaking. We conclude that more data is required associated with shallow, crustal events with Mw > 7 in order to determine whether or not Japan is susceptible to regional triggering.

Estimation of prenatal aorta intima-media thickness in ultrasound examination

NASA Astrophysics Data System (ADS)

Veronese, Elisa; Poletti, Enea; Cosmi, Erich; Grisan, Enrico

2012-03-01

Prenatal events such as intrauterine growth restriction have been shown to be associated with an increased thickness of abdominal aorta in the fetus. Therefore the measurement of abdominal aortic intima-media thickness (aIMT) has been recently considered a sensitive marker of artherosclerosis risk. To date measure of aortic diameter and of aIMT has been performed manually on US fetal images, thus being susceptible to intra- and inter- operator variability. This work introduces an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from videos recorded during routine third trimester ultrasonographic fetal biometry. Firstly, in each frame, the algorithm locates and segments the region corresponding to aorta by means of an active contour driven by two different external forces: a static vector field convolution force and a dynamic pressure force. Then, in each frame, the mean diameter of the vessel is computed, to reconstruct the cardiac cycle: in fact, we expect the diameter to have a sinusoidal trend, according to the heart rate. From the obtained sinusoid, we identify the frames corresponding to the end diastole and to the end systole. Finally, in these frames we assess the aIMT. According to its definition, we consider as aIMT the distance between the leading edge of the blood-intima interface, and the leading edge of the media-adventitia interface on the far wall of the vessel. The correlation between end-diastole and end-systole aIMT automatic and manual measures is 0.90 and 0.84 respectively.

Elastin aging and lipid oxidation products in human aorta.

PubMed

Zarkovic, Kamelija; Larroque-Cardoso, Pauline; Pucelle, Mélanie; Salvayre, Robert; Waeg, Georg; Nègre-Salvayre, Anne; Zarkovic, Neven

2015-01-01

Vascular aging is associated with structural and functional modifications of the arteries, and by an increase in arterial wall thickening in the intima and the media, mainly resulting from structural modifications of the extracellular matrix (ECM) components. Among the factors known to accumulate with aging, advanced lipid peroxidation end products (ALEs) are a hallmark of oxidative stress-associated diseases such as atherosclerosis. Aldehydes generated from the peroxidation of polyunsaturated fatty acids (PUFA), (4-hydroxynonenal, malondialdehyde, acrolein), form adducts on cellular proteins, leading to a progressive protein dysfunction with consequences in the pathophysiology of vascular aging. The contribution of these aldehydes to ECM modification is not known. This study was carried out to investigate whether aldehyde-adducts are detected in the intima and media in human aorta, whether their level is increased in vascular aging, and whether elastin fibers are a target of aldehyde-adduct formation. Immunohistological and confocal immunofluorescence studies indicate that 4-HNE-histidine-adducts accumulate in an age-related manner in the intima, media and adventitia layers of human aortas, and are mainly expressed in smooth muscle cells. In contrast, even if the structure of elastin fiber is strongly altered in the aged vessels, our results show that elastin is not or very poorly modified by 4-HNE. These data indicate a complex role for lipid peroxidation and in particular for 4-HNE in elastin homeostasis, in the vascular wall remodeling during aging and atherosclerosis development. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Elastin aging and lipid oxidation products in human aorta

PubMed Central

Zarkovic, Kamelija; Larroque-Cardoso, Pauline; Pucelle, Mélanie; Salvayre, Robert; Waeg, Georg; Nègre-Salvayre, Anne; Zarkovic, Neven

2014-01-01

Vascular aging is associated with structural and functional modifications of the arteries, and by an increase in arterial wall thickening in the intima and the media, mainly resulting from structural modifications of the extracellular matrix (ECM) components. Among the factors known to accumulate with aging, advanced lipid peroxidation end products (ALEs) are a hallmark of oxidative stress-associated diseases such as atherosclerosis. Aldehydes generated from the peroxidation of polyunsaturated fatty acids (PUFA), (4-hydroxynonenal, malondialdehyde, acrolein), form adducts on cellular proteins, leading to a progressive protein dysfunction with consequences in the pathophysiology of vascular aging. The contribution of these aldehydes to ECM modification is not known. This study was carried out to investigate whether aldehyde-adducts are detected in the intima and media in human aorta, whether their level is increased in vascular aging, and whether elastin fibers are a target of aldehyde-adduct formation. Immunohistological and confocal immunofluorescence studies indicate that 4-HNE-histidine-adducts accumulate in an age-related manner in the intima, media and adventitia layers of human aortas, and are mainly expressed in smooth muscle cells. In contrast, even if the structure of elastin fiber is strongly altered in the aged vessels, our results show that elastin is not or very poorly modified by 4-HNE. These data indicate a complex role for lipid peroxidation and in particular for 4-HNE in elastin homeostasis, in the vascular wall remodeling during aging and atherosclerosis development. PMID:25553420

Long-term effect of losartan administration on blood pressure, heart and structure of coronary artery of young spontaneously hypertensive rats.

PubMed

KOPRDOVA, R; CEBOVA, M; KRISTEK, F

2009-01-01

Alterations in geometry and structure of coronary arteries have marked consequences on blood flow to the respective area. We evaluated long-term effect of losartan on blood pressure (BP), heart weight/body weight (HW/BW), geometry and structure of septal branch of coronary artery (RS) of young SHR and Wistar rats. Four-week-old Wistar rats and SHR were used. Losartan was administered (20 mg/kg/day) in drinking water by gavage for 5 weeks. BP was measured by plethysmographic method. Cardiovascular system was perfused with a fixative (120 mm Hg). RS was processed for electron microscopy. Wall thickness of intima + media (WT), inner diameter (ID), cross-sectional area of intima + media (CSA), volume densities (VD) of endothelial cells (EC), extracellular matrix (ECM) of intima, smooth muscle cells (SMC) and ECM of media were evaluated. BP of 4-week-old SHR did not differ from that of Wistar rats. BP, HW/BW, WT, CSA, WT/ID, CSAs of SMC, ECM of media were increased in 9-week-old SHR, whereas their VD and CSA of EC were decreased. Losartan administration decreased BP and HW/BW in both groups. Geometry of RS was affected only in SHR (reduction of WT, CSA, WT/ID and increased of ID, circumferential tension, VD and CSA of EC). Losartan administration reduced BP and myocardial mass in both groups and beneficially affected geometry and structure of coronary artery in SHR.

Quantification of atherosclerosis with MRI and image processing in spontaneously hyperlipidemic rabbits.

PubMed

Hänni, Mari; Edvardsson, H; Wågberg, M; Pettersson, K; Smedby, O

2004-01-01

The need for a quantitative method to assess atherosclerosis in vivo is well known. This study tested, in a familiar animal model of atherosclerosis, a combination of magnetic resonance imaging (MRI) and image processing. Six spontaneously hyperlipidemic (Watanabe) rabbits were examined with a knee coil in a 1.5-T clinical MRI scanner. Inflow angio (2DI) and proton density weighted (PDW) images were acquired to examine 10 cm of the aorta immediately cranial to the aortic bifurcation. Examination of the thoracic aorta was added in four animals. To identify the inner and outer boundary of the arterial wall, a dynamic contour algorithm (Gradient Vector Flow snakes) was applied to the 2DI and PDW images, respectively, after which the vessel wall area was calculated. The results were compared with histopathological measurements of intima and intima-media cross-sectional area. The correlation coefficient between wall area measurements with MRI snakes and intima-media area was 0.879 when computed individual-wise for abdominal aortas, 0.958 for thoracic aortas, and 0.834 when computed segment-wise. When the algorithm was applied to the PDW images only, somewhat lower correlations were obtained. The MRI yielded significantly higher values than histopathology, which excludes the adventitia. Magnetic resonance imaging, in combination with dynamic contours, may be a suitable technique for quantitative assessment of atherosclerosis in vivo. Using two sequences for the measurement seems to be superior to using a single sequence.

Coffee, decaffeinated coffee, caffeine, and tea consumption in young adulthood and atherosclerosis later in life: the CARDIA study.

PubMed

Reis, Jared P; Loria, Catherine M; Steffen, Lyn M; Zhou, Xia; van Horn, Linda; Siscovick, David S; Jacobs, David R; Carr, J Jeffrey

2010-10-01

To determine the association of coffee, decaffeinated coffee, caffeine, and tea consumption in young adulthood with the presence and progression of coronary artery calcified (CAC) plaque and carotid intima-media thickness later in life. The Coronary Artery Risk Development in Young Adults (CARDIA) Study is a cohort of 5115 white and black adults who were aged 18 to 30 years when they completed a baseline clinic examination from 1985 to 1986. Subsequent examinations were conducted 2, 5, 7, 10, 15, and 20 years later. After multivariable adjustment, no association was observed between average coffee, decaffeinated coffee, or caffeine consumption (years 0 and 7) and presence of CAC (score, >0 Agatston units at year 15 or 20), CAC progression (incident CAC at year 20 or increase in CAC score by ≥20 Agatston units), or high carotid intima-media thickness (>80th percentile, year 20). However, tea consumption displayed a nonsignificant trend for an inverse association with CAC (P=0.08 for trend) and an inverse association with CAC progression (P=0.04 for trend) but no association with high carotid intima-media thickness (P>0.20 for trend). Stratification of the coffee analyses by sex, race, or smoking yielded similar nonsignificant patterns. We observed no substantial association between coffee or caffeine intake and coronary and carotid atherosclerosis. However, our results suggested an inverse association between tea and CAC but not carotid atherosclerosis.

Carotid intima-media thickness in young survivors of childhood cancer.

PubMed

Krawczuk-Rybak, Maryna; Tomczuk-Ostapczuk, Monika; Panasiuk, Anna; Goscik, Elzbieta

2017-02-01

Radiotherapy (RT) and some chemotherapy regimens are known risk factors predisposing to the development of premature arterial disease. Vascular ultrasound measurement of carotid intima-media thickness (IMT) is a non-invasive technique, useful to detect early subclinical symptoms of atherosclerosis that can appear in the paediatric population. We analysed the influence of chemotherapy and moderate doses of head or neck irradiation in childhood cancer survivors on the possibility of premature carotid artery disease. Ultrasound measurements of the intima-media thickness (IMT) in the common carotid artery (CCA), bulb and internal carotid artery (ICA) were performed in 74 young cancer survivors and in 48 age- and sex-matched controls. In the whole study group, we observed higher IMT in all positions as compared with the control, except for comparable thickness in the CCA (bilaterally). We failed to find any differences in IMT between irradiated and non-irradiated females. In irradiated males, all IMT measurements on the right side were higher than in non-irradiated patients. There was no effect of body mass index, blood pressure, serum cholesterol, triglycerides, fibrinogen and thyroid hormones on IMT. In the irradiated group, a positive correlation was observed between IMT in the right bulb and the post-radiation time. Anticancer treatment during childhood, especially including irradiation to the mediastinum, head or neck, affects the IMT, particularly in males. This suggests a possible role of irradiation in the premature development of carotid artery disease. © 2016 The Royal Australian and New Zealand College of Radiologists.

Landslides in everyday life: An interdisciplinary approach to understanding vulnerability in the Himalayas

NASA Astrophysics Data System (ADS)

Sudmeier-Rieux, K.; Breguet, A.; Dubois, J.; Jaboyedoff, M.

2009-04-01

Several thousand landslides were triggered by the Kashmir earthquake, scarring the hillside with cracks. Monsoon rains continue to trigger landslides, which have increased the exposure of populations because of lost agricultural lands, blocked roads and annual fatalities due to landslides. The great majority of these landslides are shallow and relatively small but greatly impacting the population. In this region, landslides were a factor before the earthquake, mainly due to road construction and gravel excavation, but the several thousand landslides triggered by the earthquake have completely overwhelmed the local population and authorities. In Eastern Nepal, the last large earthquake to hit this region occurred in 1988, also triggering numerous landslides and cracks. Here, landslides can be considered a more common phenomenon, yet coping capacities amount to local observations of landslide movement, subsequent abandonment of houses and land as they become too dangerous. We present a comparative case study from Kashmir, Pakistan and Eastern Nepal, highlighting an interdisciplinary approach to understanding the complex interactions between land use, landslides and vulnerability. Our approach sets out to understand underlying causes of the massive landslides triggered by the 2005 earthquake in Kashmir, Pakistan, and also the increasing number of landslides in Nepal. By approaching the issue of landslides from multiple angles (risk perceptions, land use, local coping capacities, geological assessment, risk mapping) and multiple research techniques (remote sensing, GIS, geological assessment, participatory mapping, focus groups) we are better able to create a more complete picture of the "hazardscape". We find that by combining participatory social science research with hazard mapping, we obtain a more complete understanding of underlying causes, coping strategies and possible mitigation options, placing natural hazards in the context of everyday life. This method is relatively simple, low cost and useful to local authorities or development agencies in planning and managing development projects, which include a hazard management aspect. We discuss some of our successes, some obstacles and ideas for future research.

Comparison of the effects of antihypertensive treatment with angiotensin II blockade and beta-blockade on carotid wall structure and haemodynamics: protocol and baseline demographics.

PubMed

Ariff, Ben; Stanton, Alice; Barratt, Dean; Augst, Alex; Glor, Fadi; Poulter, Neil; Sever, Peter; Xu, Yun; Hughes, Alun; Thom, Simon A Mc G

2002-06-01

Several systemic factors have been shown to contribute to the acceleration of large vessel atheroma. Correction of these factors leads to a reduction in the progression of plaque formation and associated arterial wall thickness. Atheroma remains, however, a focal disease, developing at characteristic sites within the arterial tree. These sites are typically at areas of vessel branching or marked curvature, and correspond to regions of high tensile stress and low sheer stress, leading to the hypothesis that local haemodynamic factors and vessel wall mechanics potentiate the focal development of atheroma. Current assessment of vascular haemodynamics suffers from an inability to handle complex flow, and does not allow accurate determination of locally varying flow, and shear stress patterns. The application of computational fluid dynamic (CFD) flow simulation techniques to ultrasound and local pressure data, however, allows a comprehensive, non-invasive appraisal of haemodynamic flow parameters to be performed. The Candesartan cilexetil and Atenolol Carotid Haemodynamic Endpoint Trial (CACHET) study compares the effects of two antihypertensive regimens, one b-blocker-based, the other angiotensin receptor blocker based, on carotid intima-media thickness. The collection of ultrasound and pressure data on each subject provides a unique opportunity to apply these data to the CFD model to study the effects of these antihypertensive regimens on local fluid dynamics. This will lead to a greater understanding of the relationship of these factors to atheroma formation and regression.

Distributed event-triggered consensus tracking of second-order multi-agent systems with a virtual leader

NASA Astrophysics Data System (ADS)

Jie, Cao; Zhi-Hai, Wu; Li, Peng

2016-05-01

This paper investigates the consensus tracking problems of second-order multi-agent systems with a virtual leader via event-triggered control. A novel distributed event-triggered transmission scheme is proposed, which is intermittently examined at constant sampling instants. Only partial neighbor information and local measurements are required for event detection. Then the corresponding event-triggered consensus tracking protocol is presented to guarantee second-order multi-agent systems to achieve consensus tracking. Numerical simulations are given to illustrate the effectiveness of the proposed strategy. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203147, 61374047, and 61403168).

Extending earthquakes' reach through cascading.

PubMed

Marsan, David; Lengliné, Olivier

2008-02-22

Earthquakes, whatever their size, can trigger other earthquakes. Mainshocks cause aftershocks to occur, which in turn activate their own local aftershock sequences, resulting in a cascade of triggering that extends the reach of the initial mainshock. A long-lasting difficulty is to determine which earthquakes are connected, either directly or indirectly. Here we show that this causal structure can be found probabilistically, with no a priori model nor parameterization. Large regional earthquakes are found to have a short direct influence in comparison to the overall aftershock sequence duration. Relative to these large mainshocks, small earthquakes collectively have a greater effect on triggering. Hence, cascade triggering is a key component in earthquake interactions.

Parent Trigger Laws and the Promise of Parental Voice

ERIC Educational Resources Information Center

Smith, William C.; Rowland, Julie

2014-01-01

Parent trigger laws have gained momentum nationally under the premise that they will increase local authority by amplifying parental voice in the decision to turn around "failing" schools. Using Hirschman's exit, voice, and loyalty framework we create two conceptual models of voice and evaluate the promise of voice in California, home of…

Assimilation as Attraction: Computing Distance, Similarity, and Locality in Phonology

ERIC Educational Resources Information Center

Wayment, Adam

2009-01-01

This dissertation explores similarity effects in assimilation, proposing an Attraction Framework to analyze cases of parasitic harmony where a trigger-target pair only results in harmony if the trigger and target agree on other features. Attraction provides a natural model of these effects by relating the pressure for assimilation to the…

The global aftershock zone

USGS Publications Warehouse

Parsons, Thomas E.; Margaret Segou,; Warner Marzocchi,

2014-01-01

The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often superposed onto already seismically active regions, making them difficult to detect and understand. From a hazard perspective we are concerned that this dynamic process might encourage other high magnitude earthquakes, and wonder if a global alarm state is warranted after every large mainshock. From an earthquake process perspective we are curious about the physics of earthquake triggering across the magnitude spectrum. In this review we build upon past studies that examined the combined global response to mainshocks. Such compilations demonstrate significant rate increases during, and immediately after (~ 45 min) M > 7.0 mainshocks in all tectonic settings and ranges. However, it is difficult to find strong evidence for M > 5 rate increases during the passage of surface waves in combined global catalogs. On the other hand, recently published studies of individual large mainshocks associate M > 5 triggering at global range that is delayed by hours to days after surface wave arrivals. The longer the delay between mainshock and global aftershock, the more difficult it is to establish causation. To address these questions, we review the response to 260 M ≥ 7.0 shallow (Z ≤ 50 km) mainshocks in 21 global regions with local seismograph networks. In this way we can examine the detailed temporal and spatial response, or lack thereof, during passing seismic waves, and over the 24 h period after their passing. We see an array of responses that can involve immediate and widespread seismicity outbreaks, delayed and localized earthquake clusters, to no response at all. About 50% of the catalogs that we studied showed possible (localized delayed) remote triggering, and ~ 20% showed probable (instantaneous broadly distributed) remote triggering. However, in any given region, at most only about 2–3% of global mainshocks caused significant local earthquake rate increases. These rate increases are mostly composed of small magnitude events, and we do not find significant evidence of dynamically triggered M > 5 earthquakes. If we assume that the few observed M > 5 events are triggered, we find that they are not directly associated with surface wave passage, with first incidences being 9–10 h later. We note that mainshock magnitude, relative proximity, amplitude spectra, peak ground motion, and mainshock focal mechanisms are not reliable determining factors as to whether a mainshock will cause remote triggering. By elimination, azimuth, and polarization of surface waves with respect to receiver faults may be more important factors.

Effect of lifestyle interventions with or without metformin therapy on serum levels of osteoprotegerin and receptor activator of nuclear factor kappa B ligand in patients with prediabetes.

PubMed

Arslan, Muyesser Sayki; Tutal, Esra; Sahin, Mustafa; Karakose, Melia; Ucan, Bekir; Ozturk, Gulfer; Cakal, Erman; Biyikli Gencturk, Zeynep; Ozbek, Mustafa; Delibasi, Tuncay

2017-02-01

Osteoprotegerin has been shown to be increased in cardiovascular disorders and type 2 diabetes mellitus. Prediabetes represents a high risk condition for diabetes and diabetic complications. Therefore, we aimed to find the relationship between prediabetes and osteoprotegerin with nuclear factor-B ligand, carotid intima media thickness, and metabolic markers. A total of 54 participants with prediabetes including impaired fasting glucose (n = 21), impaired glucose tolerance (n = 8), impaired fasting glucose and impaired glucose tolerance (n = 25), and 60 healthy individuals as a control were admitted to the study. Metabolic and anthropometric parameters, insulin resistance variables, osteoprotegerin, and nuclear factor-B ligand markers, carotid intima media thickness were examined at baseline for all participants. To evaluate the effect of therapy we determined the same parameters after the end of the study. Measurements of waist circumference, body mass index, body fat percentage and levels of fasting blood glucose, fasting insulin, homeostatic model assessment of insulin resistance, triglyceride levels and hsCRP and carotid intima media thickness were significantly higher in patients with prediabetes (p < 0.05). We also found higher osteoprotegerin and lower nuclear factor-B ligand levels in patients than in controls however, the value was non-significant (p > 0.05). Patients with prediabetes were under lifestyle interventions with (group 1, n = 33) or without metformin (group 2, n = 21) therapy. Baseline anthropometric and metabolic characteristics were not found statistically different in group 1 and group 2. Mean follow up period of the patients were 7.9 ± 2.2 month (min-max: 6-12 months). After the follow up period we evaluated the same parameters and found significant differences between waist circumference, body mass index, body fat percentage, fasting insulin, homeostatic model assessment of insulin resistance, and osteoprotegerin levels (p < 0.05). However, carotid intima media thickness, and nuclear factor-B ligand levels significantly different only in the group treated with metformin (p < 0.05). We also compared the variables after the treatment period with the control group and found significantly lower levels in terms of fasting insulin, homeostatic model assessment of insulin resistance, waist circumference, body mass index, body fat percentage, carotid intima media thickness, osteoprotegerin, and nuclear factor-B ligand values (p < 0.05). Correlation analysis revealed a negative relationship between nuclear factor-B ligand and body mass index, and body fat percentage in group 1 (p = 0.05, r = -0.646, p = 0.01, r = -0.585). Therapy of prediabetes was associated with a significant decrease in osteoprotegerin and certain metabolic variables together with an increase in nuclear factor-B ligand levels particularly in patients with under metformin therapy.

Individual progression of carotid intima media thickness as a surrogate for vascular risk (PROG-IMT): Rationale and design of a meta-analysis project

PubMed Central

Lorenz, Matthias W.; Bickel, Horst; Bots, Michiel L.; Breteler, Monique M.B.; Catapano, Alberico L.; Desvarieux, Moise; Hedblad, Bo; Iglseder, Bernhard; Johnsen, Stein Harald; Juraska, Michal; Kiechl, Stefan; Mathiesen, Ellisiv B.; Norata, Giuseppe D.; Grigore, Liliana; Polak, Joseph; Poppert, Holger; Rosvall, Maria; Rundek, Tatjana; Sacco, Ralph L.; Sander, Dirk; Sitzer, Matthias; Steinmetz, Helmuth; Stensland, Eva; Willeit, Johann; Witteman, Jacqueline; Yanez, David; Thompson, Simon G.

2013-01-01

Carotid intima media thickness (IMT) progression is increasingly used as a surrogate for vascular risk. This use is supported by data from a few clinical trials investigating statins, but established criteria of surrogacy are only partially fulfilled. To provide a valid basis for the use of IMT progression as a study end point, we are performing a 3-step meta-analysis project based on individual participant data. Objectives of the 3 successive stages are to investigate (1) whether IMT progression prospectively predicts myocardial infarction, stroke, or death in population-based samples; (2) whether it does so in prevalent disease cohorts; and (3) whether interventions affecting IMT progression predict a therapeutic effect on clinical end points. Recruitment strategies, inclusion criteria, and estimates of the expected numbers of eligible studies are presented along with a detailed analysis plan. PMID:20435179

Psychosocial Factors Associated with Subclinical Atherosclerosis in South Asians: The MASALA Study.

PubMed

Shah, Bijal M; Shah, Shriraj; Kandula, Namratha R; Gadgil, Meghana D; Kanaya, Alka M

2016-12-01

South Asians have the highest rates of premature atherosclerotic cardiovascular disease amongst all ethnic groups in the world; however this risk cannot be fully explained by traditional risk factors. Participants from the Mediators of Atherosclerosis in South Asians Living in America Study were included in this cross-sectional analysis. The purpose of this study was to investigate the association of psychosocial factors (including anger, anxiety, depressive symptoms, current and chronic stress, and everyday hassles) with carotid intima-media thickness (CIMT). Three multivariate models were examined to evaluate the association between the psychosocial factors and CIMT. Findings suggest that the impact of psychosocial factors on subclinical atherosclerosis is differential for South Asian men and women. For men, anxiety and depression were associated; while for women, stress was associated with common carotid intima media thickness, independent of traditional CVD risk factors, diet and physical activity.

Bacteria-Triggered Systemic Immunity in Barley Is Associated with WRKY and ETHYLENE RESPONSIVE FACTORs But Not with Salicylic Acid1[C][W

PubMed Central

Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G.; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F.X.

2014-01-01

Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. PMID:25332505

Cytosolic proteins can exploit membrane localization to trigger functional assembly

PubMed Central

2018-01-01

Cell division, endocytosis, and viral budding would not function without the localization and assembly of protein complexes on membranes. What is poorly appreciated, however, is that by localizing to membranes, proteins search in a reduced space that effectively drives up concentration. Here we derive an accurate and practical analytical theory to quantify the significance of this dimensionality reduction in regulating protein assembly on membranes. We define a simple metric, an effective equilibrium constant, that allows for quantitative comparison of protein-protein interactions with and without membrane present. To test the importance of membrane localization for driving protein assembly, we collected the protein-protein and protein-lipid affinities, protein and lipid concentrations, and volume-to-surface-area ratios for 46 interactions between 37 membrane-targeting proteins in human and yeast cells. We find that many of the protein-protein interactions between pairs of proteins involved in clathrin-mediated endocytosis in human and yeast cells can experience enormous increases in effective protein-protein affinity (10–1000 fold) due to membrane localization. Localization of binding partners thus triggers robust protein complexation, suggesting that it can play an important role in controlling the timing of endocytic protein coat formation. Our analysis shows that several other proteins involved in membrane remodeling at various organelles have similar potential to exploit localization. The theory highlights the master role of phosphoinositide lipid concentration, the volume-to-surface-area ratio, and the ratio of 3D to 2D equilibrium constants in triggering (or preventing) constitutive assembly on membranes. Our simple model provides a novel quantitative framework for interpreting or designing in vitro experiments of protein complexation influenced by membrane binding. PMID:29505559

Right Hemispheric Dominance in Gaze-Triggered Reflexive Shift of Attention in Humans

ERIC Educational Resources Information Center

Okada, Takashi; Sato, Wataru; Toichi, Motomi

2006-01-01

Recent findings suggest a right hemispheric dominance in gaze-triggered shifts of attention. The aim of this study was to clarify the dominant hemisphere in the gaze processing that mediates attentional shift. A target localization task, with preceding non-predicative gaze cues presented to each visual field, was undertaken by 44 healthy subjects,…

Manual B-mode versus automated radio-frequency carotid intima-media thickness measurements.

PubMed

Dogan, Soner; Plantinga, Yvonne; Dijk, Joke M; van der Graaf, Yolanda; Grobbee, Diederick E; Bots, Michiel L

2009-10-01

Carotid intima-media thickness (CIMT) serves as an indicator of atherosclerosis and cardiovascular risk. Manual measurements of B-mode ultrasound images are the most applied method. Automated measurements with radiofrequency (RF) ultrasound have been suggested as an alternative. The aim of this study was to compare these methods in terms of risk-factor relations and associations with future events. Data from participants of the Second Manifestations of Arterial Disease (SMART) study were used. Far wall common CIMT was measured online with manual B-mode and automated RF ultrasound. Measurements were performed by a group of 6 sonographers. Risk-factor information was obtained. All participants were followed for the occurrence of vascular events (mean follow-up, 2.1 years). CIMT was related to risk factors with linear regression models and to future events with Cox proportional-hazards models. Data were available for 2,146 participants. Agreement between the methods was modest (intraclass correlation coefficient = 0.34). Risk-factor relations with age and systolic blood pressure were stronger for B-mode than for RF ultrasound. Association with future events was better for B-mode than for RF ultrasound (vascular death, 1.27 vs 1.00; ischemic stroke, 1.45 vs 1.03). In participants with CIMT < 0.9 mm (without plaque), the intraclass correlation between the measures was 0.50. In addition, in that subgroup, RF ultrasound showed a stronger association with future events than B-mode ultrasound (all events, 1.59 vs 1.09; vascular death, 1.72 vs 0.93; coronary ischemic events, 1.65 vs 1.05). The preference for either B-mode or RF measurements may be driven by the type of study population, the expected presence of local atherosclerotic abnormalities, and the main aim of the study (assessing risk factors or events). However, in this study, as in many others, the B-mode approach was shown to be robust in risk-factor relations and the prediction of events.

New constraints on mechanisms of remotely triggered seismicity at Long Valley Caldera

USGS Publications Warehouse

Brodsky, E.E.; Prejean, S.G.

2005-01-01

Regional-scale triggering of local earthquakes in the crust by seismic waves from distant main shocks has now been robustly documented for over a decade. Some of the most thoroughly recorded examples of repeated triggering of a single site from multiple, large earthquakes are measured in geothermal fields of the western United States like Long Valley Caldera. As one of the few natural cases where the causality of an earthquake sequence is apparent, triggering provides fundamental constraints on the failure processes in earthquakes. We show here that the observed triggering by seismic waves is inconsistent with any mechanism that depends on cumulative shaking as measured by integrated energy density. We also present evidence for a frequency-dependent triggering threshold. On the basis of the seismic records of 12 regional and teleseismic events recorded at Long Valley Caldera, long-period waves (>30 s) are more effective at generating local seismicity than short-period waves of comparable amplitude. If the properties of the system are stationary over time, the failure threshold for long-period waves is ~0.05 cm/s vertical shaking. Assuming a phase velocity of 3.5 km/s and an elastic modulus of 3.5 x 1010Pa, the threshold in terms of stress is 5 kPa. The frequency dependence is due in part to the attenuation of the surface waves with depth. Fluid flow through a porous medium can produce the rest of the observed frequency dependence of the threshold. If the threshold is not stationary with time, pore pressures that are >99.5% of lithostatic and vary over time by a factor of 4 could explain the observations with no frequency dependence of the triggering threshold. Copyright 2005 by the American Geophysical Union.

Carotid artery intima-media thickness and erectile dysfunction in patients with metabolic syndrome.

PubMed

Unal, Mustafa; Aksoy, Duygu Yazgan; Aydın, Yusuf; Tanriover, Mine Durusu; Berker, Dilek; Karakaya, Jale; Guler, Serdar

2014-05-29

Metabolic syndrome (MS) has become a pandemic in Turkey, as is the case globally. Increase in carotid artery intima-media thickness (CIMT) and erectile dysfunction (ED) may be evident before the clinical signs of cardiovascular disease appear. We aimed to investigate the prevalence of increased CIMT and ED as markers of atherosclerotic disease in patients with MS. Thirty-two patients with MS and 29 healthy controls were included. Anthropometric and biochemical parameters, along with total testosterone (TT), high sensitive C-reactive protein (hs-CRP), were recorded. Carotid artery intima-media thickness was measured. Erectile dysfunction was assessed with International Index of Erectile Function. Patients with MS had higher BMI, fasting plasma glucose, post-prandial plasma glucose, insulin, HOMA-IR, total cholesterol, triglycerides, hs-CRP, and CIMT, whereas TT levels were lower (p<0.0001). The prevalence and severity of erectile dysfunction were higher in patients with MS (p<0.0001). Erectile dysfunction scores correlated inversely with CIMT. MS patients with ED were older and had higher CIMT compared to those without ED. Increase in age and HOMA and decrease in TT increased the risk of ED. When KIMT exceeding the 95th percentile of healthy controls was accepted as a risk factor for CVD, presence of ED was the only determinant for this increase. Erectile dysfunction was more prevalent and severe in patients with MS and correlated with subclinical endothelial dysfunction. Total testosterone deficiency was prominent among MS patients. Presence of ED points to an increased risk of cardiovascular disease when MS is present.

A theory for water and macromolecular transport in the pulmonary artery wall with a detailed comparison to the aorta

PubMed Central

Zeng, Zhongqing; Jan, Kung-Ming

2012-01-01

The pulmonary artery (PA) wall, which has much higher hydraulic conductivity and albumin void space and approximately one-sixth the normal transmural pressure of systemic arteries (e.g, aorta, carotid arteries), is rarely atherosclerotic, except under pulmonary hypertension. This study constructs a detailed, two-dimensional, wall-structure-based filtration and macromolecular transport model for the PA to investigate differences in prelesion transport processes between the disease-susceptible aorta and the relatively resistant PA. The PA and aorta models are similar in wall structure, but very different in parameter values, many of which have been measured (and therefore modified) since the original aorta model of Huang et al. (23). Both PA and aortic model simulations fit experimental data on transwall LDL concentration profiles and on the growth of isolated endothelial (horseradish peroxidase) tracer spots with circulation time very well. They reveal that lipid entering the aorta attains a much higher intima than media concentration but distributes better between these regions in the PA than aorta and that tracer in both regions contributes to observed tracer spots. Solutions show why both the overall transmural water flow and spot growth rates are similar in these vessels despite very different material transport parameters. Since early lipid accumulation occurs in the subendothelial intima and since (matrix binding) reaction kinetics depend on reactant concentrations, the lower intima lipid concentrations in the PA vs. aorta likely lead to slower accumulation of bound lipid in the PA. These findings may be relevant to understanding the different atherosusceptibilities of these vessels. PMID:22198178

Reduced arterial stiffness in very fit boys and girls.

PubMed

Weberruß, Heidi; Pirzer, Raphael; Schulz, Thorsten; Böhm, Birgit; Dalla Pozza, Robert; Netz, Heinrich; Oberhoffer, Renate

2017-01-01

Low cardiorespiratory fitness is associated with higher cardiovascular risk, whereas high levels of cardiorespiratory fitness protect the cardiovascular system. Carotid intima-media thickness and arterial distensibility are well-established parameters to identify subclinical cardiovascular disease. Therefore, this study investigated the influence of cardiorespiratory fitness and muscular strength on carotid intima-media thickness and arterial distensibility in 697 children and adolescents (376 girls), aged 7-17 years. Cardiorespiratory fitness and strength were measured with the test battery FITNESSGRAM; carotid intima-media thickness, arterial compliance, elastic modulus, stiffness index β, and pulse wave velocity β were assessed by B- and M-mode ultrasound at the common carotid artery. In bivariate correlation, cardiorespiratory fitness was significantly associated with all cardiovascular parameters and was an independent predictor in multivariate regression analysis. No significant associations were obtained for muscular strength. In a one-way variance analysis, very fit boys and girls (58 boys and 74 girls>80th percentile for cardiorespiratory fitness) had significantly decreased stiffness parameters (expressed in standard deviation scores) compared with low fit subjects (71 boys and 77 girls<20th percentile for cardiorespiratory fitness): elastic modulus -0.16±1.02 versus 0.19±1.17, p=0.009; stiffness index β -0.15±1.08 versus 0.16±1.1, p=0.03; and pulse wave velocity β -0.19±1.02 versus 0.19±1.14, p=0.005. Cardiorespiratory fitness was associated with healthier arteries in children and adolescents. Comparison of very fit with unfit subjects revealed better distensibility parameters in very fit boys and girls.

The Inverse Relationship between Cardiorespiratory Fitness and Intima-Media Thickness with Prehypertensive Middle-Aged Women.

PubMed

Kim, Dokyung; Park, Wonhah

2017-12-01

Individuals with prehypertension have a greater risk of developing hypertension and cardiovascular disease than those with normal blood pressure. Good cardiorespiratory fitness has been associated with a reduced risk for cardiovascular diseases, but whether it is related to slower progression of early atherosclerosis is unclear. We evaluated 442 women, aged 40-60 years, with resting systolic blood pressure 120-139 mmHg and diastolic blood pressure 80-89 mmHg, defined as prehypertension in cross-sectional study. Blood glucose, blood lipids and carotid intima-media thickness (CIMT) were measured at rest. Cardiorespiratory fitness (VO 2 peak) was measured by respiratory gas exchange during a treadmill exercise test. Participants were divided into three cardiorespiratory fitness levels: low, moderate, and high. The prevalence of subclinical carotid atherosclerosis was defined as a mean carotid intima-media thickness greater than the 75 th percentile. After adjustment for various confounders, a high cardiorespiratory fitness level was associated with significantly lower SBP, DBP and CIMT compared with low and moderate fitness (p < 0.05). After adjustment for established risk factors, high and moderate fitness were each associated with significantly lower odds ratios for carotid atherosclerosis 0.74 (95% CI 0.45-0.92) and 0.70 (95% CI 0.46-0.95), respectively, compared with low fitness. Our results indicate that good cardiorespiratory fitness is associated with a slower progression of early atherosclerosis in middle-aged women. These findings are important, because they emphasize that middle-aged women can be evaluated for cardiorespiratory fitness to estimate their future risk for atherosclerotic vascular diseases.

Associations of Cigarette Smoking With Subclinical Inflammation and Atherosclerosis: ELSA-Brasil (The Brazilian Longitudinal Study of Adult Health).

PubMed

Kianoush, Sina; Yakoob, Mohammad Yawar; Al-Rifai, Mahmoud; DeFilippis, Andrew P; Bittencourt, Marcio S; Duncan, Bruce B; Bensenor, Isabela M; Bhatnagar, Aruni; Lotufo, Paulo A; Blaha, Michael J

2017-06-24

There is a need to identify sensitive biomarkers of early tobacco-related cardiovascular disease. We examined the association of smoking status, burden, time since quitting, and intensity, with markers of inflammation and subclinical atherosclerosis. We studied 14 103 participants without clinical cardiovascular disease in ELSA-Brasil (Brazilian Longitudinal Study of Adult Health). We evaluated baseline cross-sectional associations between smoking parameters and inflammation (high-sensitivity C-reactive protein [hsCRP]) and measures of subclinical atherosclerosis (carotid intima-media thickness, ankle-brachial index, and coronary artery calcium [CAC]). The cohort included 1844 current smokers, 4121 former smokers, and 8138 never smokers. Mean age was 51.7±8.9 years; 44.8% were male. After multivariable adjustment, compared with never smokers, current smokers had significantly higher levels of hsCRP (β=0.24, 0.19-0.29 mg/L; P <0.001) and carotid intima-media thickness (β=0.03, 0.02-0.04 mm; P <0.001) and odds of ankle-brachial index ≤1.0 (odds ratio: 2.52; 95% confidence interval, 2.06-3.08; P <0.001) and CAC >0 (odds ratio: 1.83; 95% confidence interval, 1.46-2.30; P <0.001). Among former and current smokers, pack-years of smoking (burden) were significantly associated with hsCRP ( P <0.001 and P =0.006, respectively) and CAC ( P <0.001 and P =0.002, respectively). Among former smokers, hsCRP and carotid intima-media thickness levels and odds of ankle-brachial index ≤1.0 and CAC >0 were lower with increasing time since quitting ( P <0.01). Among current smokers, number of cigarettes per day (intensity) was positively associated with hsCRP ( P <0.001) and CAC >0 ( P =0.03) after adjusting for duration of smoking. Strong associations were observed between smoking status, burden, and intensity with inflammation (hsCRP) and subclinical atherosclerosis (carotid intima-media thickness, ankle-brachial index, CAC). These markers of early cardiovascular disease injury may be used for the further study and regulation of traditional and novel tobacco products. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Genome-wide admixture and association study of subclinical atherosclerosis in the Women’s Interagency HIV Study (WIHS)

PubMed Central

Shendre, Aditi; Wiener, Howard W.; Irvin, Marguerite R.; Aouizerat, Bradley E.; Overton, Edgar T.; Lazar, Jason; Liu, Chenglong; Hodis, Howard N.; Limdi, Nita A.; Weber, Kathleen M.; Zhi, Degui; Floris-Moore, Michelle A.; Ofotokun, Ighovwerha; Qi, Qibin; Hanna, David B.; Kaplan, Robert C.

2017-01-01

Cardiovascular disease (CVD) is a major comorbidity among HIV-infected individuals. Common carotid artery intima-media thickness (cCIMT) is a valid and reliable subclinical measure of atherosclerosis and is known to predict CVD. We performed genome-wide association (GWA) and admixture analysis among 682 HIV-positive and 288 HIV-negative Black, non-Hispanic women from the Women’s Interagency HIV study (WIHS) cohort using a combined and stratified analysis approach. We found some suggestive associations but none of the SNPs reached genome-wide statistical significance in our GWAS analysis. The top GWAS SNPs were rs2280828 in the region intergenic to mediator complex subunit 30 and exostosin glycosyltransferase 1 (MED30 | EXT1) among all women, rs2907092 in the catenin delta 2 (CTNND2) gene among HIV-positive women, and rs7529733 in the region intergenic to family with sequence similarity 5, member C and regulator of G-protein signaling 18 (FAM5C | RGS18) genes among HIV-negative women. The most significant local European ancestry associations were in the region intergenic to the zinc finger and SCAN domain containing 5D gene and NADH: ubiquinone oxidoreductase complex assembly factor 1 (ZSCAN5D | NDUF1) pseudogene on chromosome 19 among all women, in the region intergenic to vomeronasal 1 receptor 6 pseudogene and zinc finger protein 845 (VN1R6P | ZNF845) gene on chromosome 19 among HIV-positive women, and in the region intergenic to the SEC23-interacting protein and phosphatidic acid phosphatase type 2 domain containing 1A (SEC23IP | PPAPDC1A) genes located on chromosome 10 among HIV-negative women. A number of previously identified SNP associations with cCIMT were also observed and included rs2572204 in the ryanodine receptor 3 (RYR3) and an admixture region in the secretion-regulating guanine nucleotide exchange factor (SERGEF) gene. We report several SNPs and gene regions in the GWAS and admixture analysis, some of which are common across HIV-positive and HIV-negative women as demonstrated using meta-analysis, and also across the two analytic approaches (i.e., GWA and admixture). These findings suggest that local European ancestry plays an important role in genetic associations of cCIMT among black women from WIHS along with other environmental factors that are related to CVD and may also be triggered by HIV. These findings warrant confirmation in independent samples. PMID:29206233

Results of a self-triggered prototype system for radio-detection of extensive air showers at the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Abreu, P.; Acounis, S.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti&cbreve; i'c, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenir, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S. G.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Charrier, D.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, J.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fliescher, S.; Fox, B.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garçon, T.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Ionita, F.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Messina, S.; Meurer, C.; Meyhandan, R.; Mi'canovi'c, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Ponce, V. H.; Pontz, M.; Porcelli, A.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rivière, C.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schröder, F.; Schulz, J.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Silva Lopez, H. H.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanic, S.; Stapleton, J.; Stasielak, J.; Stassi, P.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Tcaciuc, R.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tkaczyj, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wommer, M.; Wundheiler, B.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano Garcia, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

2012-11-01

We describe the experimental setup and the results of RAuger, a small radio-antenna array, consisting of three fully autonomous and self-triggered radio-detection stations, installed close to the center of the Surface Detector (SD) of the Pierre Auger Observatory in Argentina. The setup has been designed for the detection of the electric field strength of air showers initiated by ultra-high energy cosmic rays, without using an auxiliary trigger from another detection system. Installed in December 2006, RAuger was terminated in May 2010 after 65 registered coincidences with the SD. The sky map in local angular coordinates (i.e., zenith and azimuth angles) of these events reveals a strong azimuthal asymmetry which is in agreement with a mechanism dominated by a geomagnetic emission process. The correlation between the electric field and the energy of the primary cosmic ray is presented for the first time, in an energy range covering two orders of magnitude between 0.1 EeV and 10 EeV. It is demonstrated that this setup is relatively more sensitive to inclined showers, with respect to the SD. In addition to these results, which underline the potential of the radio-detection technique, important information about the general behavior of self-triggering radio-detection systems has been obtained. In particular, we will discuss radio self-triggering under varying local electric-field conditions.

Managing Pain Caused By Neurological Disease

PubMed Central

Tunks, Eldon

1985-01-01

Stabbing paroxysmal pain due to neurological disease can often be controlled by anticonvulsants, whereas steady burning pain is often responsive to tricyclic antidepressants, and to neuroleptics. Overuse of opiates may actually aggravate the pain, necessitating detoxification. Transcutaneous electrical nerve stimulation is helpful for conditions in which pain is localized, especially if there is a ‘trigger area’ or neuroma, or if paresthesias can be stimulated within the painful area. Local anesthetic injection, possibly with corticosteroid, relieves painful scars and neuromas, neuritis, and tender trigger points. Sympathetic blocks are used for post-herpetic neuralgia and sympathetic dystrophies. Relaxation therapy is a very useful psychological treatment. PMID:21274032

Widespread Triggering of Earthquakes in the Central US by the 2011 M9.0 Tohoku-Oki Earthquake

NASA Astrophysics Data System (ADS)

Rubinstein, J. L.; Savage, H. M.

2011-12-01

The strong shaking of the 2011 M9.0 off-Tohoku earthquake triggered tectonic tremor and earthquakes in many locations around the world. We analyze broadband records from the USARRAY to identify triggered seismicity in more than 10 different locations in the Central United States. We identify triggered events in many states including: Kansas, Nebraska, Arkansas, Minnesota, and Iowa. The locally triggered earthquakes are obscured in broadband records by the Tohoku-Oki mainshock but can be revealed with high-pass filtering. With the exception of one location (central Arkansas), the triggered seismicity occurred in regions that are seismically quiet. The coincidence of this seismicity with the Tohoku-Oki event suggests that these earthquakes were triggered. The triggered seismicity in Arkansas occurred in a region where there has been an active swarm of seismicity since August 2010. There are two lines of evidence to indicate that the seismicity in Arkansas is triggered instead of part of the swarm: (1) we observe two earthquakes that initiate coincident with the arrival of shear wave and Love wave; (2) the seismicity rate increased dramatically following the Tohoku-Oki mainshock. Our observations of widespread earthquake triggering in regions thought to be seismically quiet remind us that earthquakes can occur in most any location. Studying additional teleseismic events has the potential to reveal regions with a propensity for earthquake triggering.

A non-contact approach for PWV detection: application in a clinical setting.

PubMed

Campo, Adriaan; Heuten, Hilde; Goovaerts, Inge; Ennekens, Guy; Vrints, Christiaan; Dirckx, Joris

2016-07-01

A need for screening methods for arteriosclerosis led to the development of several approaches to measure pulse wave velocity (PWV) being indicative of arterial stiffness. Carotid-femoral PWV (cfPWV) can be measured between common carotid artery (CCA) and femoral artery (FA) displaying the physiologically important stiffness of the conduit arteries. However, this measurement approach has several disadvantages, and a local PWV-measurement of CCA-stiffness has been proposed as an alternative in the past. In the presented pilot study, laser Doppler vibrometry (LDV) is used to measure PWV locally in the CCA (PWVLDV) in 48 patients aged between 48 and 70, with known atherosclerotic arterial disease: stabilized coronary artery disease (CAD), cerebro-vascular disease (CVD) or peripheral artery disease (PAD). Additionally, cfPWV, CCA distensibility coefficient (DC), CCA intima-media thickness (IMT), blood pressure (BP) and age were evaluated. LDV is a valid method for local PWV-measurement. The method is potentially easy to use, and causes no discomfort to the patient. PWVLDV correlates with age (R  =  0.432; p  =  0.002) as reported in related studies using other techniques, and measured values lay between 2.5 and 5.8 m s(-1), which is well in line with literature measures of local PWV in the CCA. In conclusion, PWVLDV potentially is a marker for arterial health, but more research in a larger and more homogeneous patient population is mandatory. In future studies, blood velocity measurements should be incorporated, as well as a reference method such as pulse wave imaging (PWI) or magnetic resonance imaging (MRI).

Postural changes may influence popliteal atherosclerosis by modifying local circumferential wall tension.

PubMed

Gemignani, Tiago; Matos-Souza, José R; Coelho, Otávio R; Franchini, Kleber G; Nadruz, Wilson

2008-11-01

Atherosclerosis of peripheral arteries typically affects vessels of the lower limbs, suggesting that local hemodynamic stimuli play a role in this process. Our study evaluated the effects of body postural changes on carotid and popliteal blood pressure, circumferential wall tension (CWT) and arterial strain, and investigated the relationship between such hemodynamic parameters and intima-media thickness (IMT) of these arteries. One hundred seventeen nondiabetic, nonhypertensive, nonsmoker subjects (48 men and 69 women) were enrolled and had their blood pressure measured in the arm and calf in supine and orthostatic positions. Echo-doppler analysis evaluated the common carotid and popliteal arteries after blood pressure measurements, while CWT was calculated according to Laplace's law. The results showed that changing from supine to orthostatic posture increased blood pressure and CWT in popliteal but not in carotid arteries. Partial correlation analysis adjusted for age and body mass index revealed no major relationship between IMT of the studied vessels and local blood pressure or arterial strain. Conversely, supine and orthostatic CWT exhibited comparable correlation coefficients with carotid IMT, while orthostatic CWT displayed a stronger relationship with popliteal IMT than with supine CWT. These results were confirmed by multiple linear regression analysis that included age, sex, body mass index, lipid fractions and glucose as independent variables. Overall, our results indicate that orthostatic CWT is a stronger hemodynamic predictor of popliteal IMT than supine CWT, suggesting that erectile posture may be a potential risk factor for popliteal atherosclerosis because it increases the local hemodynamic burden. (Hypertens Res 2008; 31: 2059-2064).

Analysis of PAMP-Triggered ROS Burst in Plant Immunity.

PubMed

Sang, Yuying; Macho, Alberto P

2017-01-01

The plant perception of pathogen-associated molecular patterns triggers a plethora of cellular immune responses. One of these responses is a rapid and transient burst of reactive oxygen species (ROS) mediated by plasma membrane-localized NADPH oxidases. The ROS burst requires a functional receptor complex and the contribution of several additional regulatory components. In laboratory conditions, the ROS burst can be detected a few minutes after the treatment with an immunogenic microbial elicitor. For these reasons, the elicitor-triggered ROS burst has been often exploited as readout to probe the contribution of plant components to early immune responses. Here, we describe a detailed protocol for the measurement of elicitor-triggered ROS burst in a simple, fast, and easy manner.

Bacteria-triggered systemic immunity in barley is associated with WRKY and ETHYLENE RESPONSIVE FACTORs but not with salicylic acid.

PubMed

Dey, Sanjukta; Wenig, Marion; Langen, Gregor; Sharma, Sapna; Kugler, Karl G; Knappe, Claudia; Hause, Bettina; Bichlmeier, Marlies; Babaeizad, Valiollah; Imani, Jafargholi; Janzik, Ingar; Stempfl, Thomas; Hückelhoven, Ralph; Kogel, Karl-Heinz; Mayer, Klaus F X; Vlot, A Corina

2014-12-01

Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity. © 2014 American Society of Plant Biologists. All Rights Reserved.

Slip triggered on southern California faults by the 1992 Joshua Tree, Landers, and big bear earthquakes

USGS Publications Warehouse

Bodin, Paul; Bilham, Roger; Behr, Jeff; Gomberg, Joan; Hudnut, Kenneth W.

1994-01-01

Five out of six functioning creepmeters on southern California faults recorded slip triggered at the time of some or all of the three largest events of the 1992 Landers earthquake sequence. Digital creep data indicate that dextral slip was triggered within 1 min of each mainshock and that maximum slip velocities occurred 2 to 3 min later. The duration of triggered slip events ranged from a few hours to several weeks. We note that triggered slip occurs commonly on faults that exhibit fault creep. To account for the observation that slip can be triggered repeatedly on a fault, we propose that the amplitude of triggered slip may be proportional to the depth of slip in the creep event and to the available near-surface tectonic strain that would otherwise eventually be released as fault creep. We advance the notion that seismic surface waves, perhaps amplified by sediments, generate transient local conditions that favor the release of tectonic strain to varying depths. Synthetic strain seismograms are presented that suggest increased pore pressure during periods of fault-normal contraction may be responsible for triggered slip, since maximum dextral shear strain transients correspond to times of maximum fault-normal contraction.

Tsunami hazard assessment for the Azores archipelago: a historical review

NASA Astrophysics Data System (ADS)

Cabral, Nuno; Ferreira, Teresa; Queiroz, Maria Gabriela

2010-05-01

The Azores islands due to its complex geographical and geodynamic setting are exposed to tsunamigenic events associated to different triggering mechanisms, local or distant. Since the settlement of the Azores, in the fifteenth century, there are several documents that relate coastal areas flooding episodes with unusually high waves which caused death and destruction. This work had as main objective the characterization of the different events that can be associated with tsunamigenic phenomena, registered in the archipelago. With this aim, it was collected diverse documentation like chronics, manuscripts, newspaper articles and magazines, scientific publications, and international databases available online. From all the studied tsunami events it was identified the occurrence of some teletsunamis, among which the most relevant was triggered by the 1st November 1755 Lisbon earthquake, with an epicenter SW of Portugal, which killed 6 people in Terceira island. It is also noted the teletsunami generated by the 1761 earthquake, located in the same region as the latest, and the one generated in 1929 by an earthquake-triggered submarine landslide in the Grand Banks of Newfoundland. From the local events, originated in the Azores, the most significant were the tsunamis triggered by 1757 and 1980 earthquakes, both associated with the Terceira Rift dynamics. In the first case the waves may also be due to earthquake-triggered. With respect to tsunamis triggered by sea cliffs landslides it is important to mention the 1847 Quebrada Nova and the 1980 Rocha Alta events, both located in the Flores Island. The 1847 event is the deadliest tsunami recorded in Azores since 10 people died in Flores and Corvo islands in result of the propagated wave. The developed studies improve knowledge of the tsunami sources that affected the Azores during its history, also revealing the importance of awareness about this natural phenomenon. The obtained results showed that the tsunami hazard in the Azores is mostly driven from the events triggered by distant earthquakes and local earthquakes and landslides. In this context, were identified 12 tsunami events. In another context, it were identified 6 events associated with coastal areas flooding due to floods and/or extreme weather phenomena, hypothetically identified as meteotsunamis. It should be stressed that, despite the differences associated with their triggering mechanisms, both the tsunamis generated by geological factors and those related to atmospheric phenomena may have similar impact. Although the absence of reports identifying tsunamis associated with volcanic activity, the eruptive history of the Azores active volcanoes shows high magnitude eruptions with considerable tsunamigenic potential.

Localized scleroderma.

PubMed

Kreuter, Alexander

2012-01-01

Localized scleroderma (also called morphea) is a term encompassing a spectrum of sclerotic autoimmune diseases that primarily affect the skin, but also might involve underlying structures such as the fat, fascia, muscle, and bones. Its exact pathogenesis is still unknown, but several trigger factors in genetically predisposed individuals might initially lead to an immunologically triggered release of pro-inflammatory cytokines, resulting in a profound dysregulation of the connective tissue metabolism and ultimately to induction of fibrosis. To date, there are no specific serological markers available for localized scleroderma. Within the last years, several validated clinical scores have been introduced as potential outcome measures for the disease. Given the rarity of localized scleroderma, only few evidence-based therapeutical treatment options exist. So far, the most robust data is available for ultraviolet A1 phototherapy in disease that is restricted to the skin, and methotrexate alone or in combination with systemic corticosteroids in more severe disease that additionally affects extracutaneous structures. This practical review summarizes relevant information on the epidemiology, pathogenesis, clinical subtypes and classifications, differential diagnoses, clinical scores and outcome measures, and current treatment strategies of localized scleroderma. © 2012 Wiley Periodicals, Inc.

Plant immunity: a lesson from pathogenic bacterial effector proteins.

PubMed

Cui, Haitao; Xiang, Tingting; Zhou, Jian-Min

2009-10-01

Phytopathogenic bacteria inject an array of effector proteins into host cells to alter host physiology and assist the infection process. Some of these effectors can also trigger disease resistance as a result of recognition in the plant cell by cytoplasmic immune receptors. In addition to effector-triggered immunity, plants immunity can be triggered upon the detection of Pathogen/Microbe-Associated Molecular Patterns by surface-localized immune receptors. Recent progress indicates that many bacterial effector proteins use a variety of biochemical properties to directly attack key components of PAMP-triggered immunity and effector-triggered immunity, providing new insights into the molecular basis of plant innate immunity. Emerging evidence indicate that the evolution of disease resistance in plants is intimately linked to the mechanism by which bacterial effectors promote parasitism. This review focuses on how these studies have conceptually advanced our understanding of plant-pathogen interactions.

Overexpression of Mitofusin 2 inhibited oxidized low-density lipoprotein induced vascular smooth muscle cell proliferation and reduced atherosclerotic lesion formation in rabbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo Yanhong; Chen Kuanghueih; Gao Wei

2007-11-16

Our previous studies have implies that Mitofusin 2 (Mfn2), which was progressively reduced in arteries from ApoE{sup -/-} mice during the development of atherosclerosis, may take part in pathogenesis of atherosclerosis. In this study, we found that overexpression of Mfn2 inhibited oxidized low-density lipoprotein or serum induced vascular smooth muscle cell proliferation by down-regulation of Akt and ERK phosphorylation. Then we investigated the in vivo role of Mfn2 on the development of atherosclerosis in rabbits using adenovirus expressing Mitofusin 2 gene (AdMfn2). By morphometric analysis we found overexpression of Mfn2 inhibited atherosclerotic lesion formation and intima/media ratio by 66.7% andmore » 74.6%, respectively, compared with control group. These results suggest that local Mfn2 treatment suppresses the development of atherosclerosis in vivo in part by attenuating the smooth muscle cell proliferation induced by lipid deposition and vascular injury.« less

The hair-trigger effect for a class of nonlocal nonlinear equations

NASA Astrophysics Data System (ADS)

Finkelshtein, Dmitri; Tkachov, Pasha

2018-06-01

We prove the hair-trigger effect for a class of nonlocal nonlinear evolution equations on which have only two constant stationary solutions, 0 and . The effect consists in that the solution with an initial condition non identical to zero converges (when time goes to ) to θ locally uniformly in . We also find sufficient conditions for existence, uniqueness and comparison principle in the considered equations.

GLAST's GBM Burst Trigger

NASA Technical Reports Server (NTRS)

Band, D.; Briggs, M.; Connaughton, V.; Kippen, M.; Preece, R.

2003-01-01

The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

Predictive performance of rainfall thresholds for shallow landslide triggering in Switzerland from daily gridded precipitation data

NASA Astrophysics Data System (ADS)

Leonarduzzi, E.; Molnar, P.; McArdell, B. W.

2017-12-01

In Switzerland floods are responsible for most of the damage caused by rainfall-triggered natural hazards (89%), followed by landslides (6%, almost 600 M USD) as reported in Hilker et al. (2009) for the period 1972-2007. A high-resolution gridded daily precipitation dataset is combined with a landslide inventory containing over 2000 events in the period 1972-2012 to analyze rainfall thresholds that lead to landsliding in Switzerland. First triggering rainfall and landslides are co-located obtaining the distributions of triggering and non-triggering rainfall event properties at the scale of the precipitation data (2*2 km2) and considering 1 day as the interarrival time to separate events. Then rainfall thresholds are obtained by maximizing true positives (accurate predictions) while minimizing false negatives (false alarms), using the True Skill Statistic. The best predictive performance is obtained by the intensity-duration ID threshold curve, followed by peak daily intensity (Imax) and mean event intensity (Imean). Event duration by itself has very low predictive power. In addition to country-wide thresholds, local ones are also defined by regionalization based on surface erodibility and local long-term climate (mean daily precipitation). Different Imax thresholds are determined for each of the regions separately. It is found that wetter local climate and lower erodibility lead to significantly higher rainfall thresholds required to trigger landslides. However, the improvement in model performance due to regionalization is marginal and much lower than what can be achieved by having a high quality landslide database. In order to validate the performance of the Imax rainfall threshold model, reference cases will be presented in which the landslide locations and timing are randomized and the landslide sample size is reduced. Jack-knife and cross-validation experiments demonstrate that the model is robust. The results highlight the potential of using rainfall I-D threshold curves and Imax threshold values for predicting the occurrence of landslides on a country or regional scale even with daily precipitation data, with possible applications in landslide warning systems.

Spatial focalization of pheromone/MAPK signaling triggers commitment to cell–cell fusion

PubMed Central

Merlini, Laura

2016-01-01

Cell fusion is universal in eukaryotes for fertilization and development, but what signals this process is unknown. Here, we show in Schizosaccharomyces pombe that fusion does not require a dedicated signal but is triggered by spatial focalization of the same pheromone–GPCR (G-protein-coupled receptor)–MAPK signaling cascade that drives earlier mating events. Autocrine cells expressing the receptor for their own pheromone trigger fusion attempts independently of cell–cell contact by concentrating pheromone release at the fusion focus, a dynamic actin aster underlying the secretion of cell wall hydrolases. Pheromone receptor and MAPK cascade are similarly enriched at the fusion focus, concomitant with fusion commitment in wild-type mating pairs. This focalization promotes cell fusion by immobilizing the fusion focus, thus driving local cell wall dissolution. We propose that fusion commitment is imposed by a local increase in MAPK concentration at the fusion focus, driven by a positive feedback between fusion focus formation and focalization of pheromone release and perception. PMID:27798845

ATLAS trigger operations: Upgrades to ``Xmon'' rate prediction system

NASA Astrophysics Data System (ADS)

Myers, Ava; Aukerman, Andrew; Hong, Tae Min; Atlas Collaboration

2017-01-01

We present ``Xmon,'' a tool to monitor trigger rates in the Control Room of the ATLAS Experiment. We discuss Xmon's recent (1) updates, (2) upgrades, and (3) operations. (1) Xmon was updated to modify the tool written for the three-level trigger architecture in Run-1 (2009-2012) to adapt to the new two-level system for Run-2 (2015-current). The tool takes as input the beam luminosity to make a rate prediction, which is compared with incoming rates to detect anomalies that occur both globally throughout a run and locally within a run. Global offsets are more commonly caught by the predictions based upon past runs, where offline processing allows for function adjustments and fit quality through outlier rejection. (2) Xmon was upgraded to detect local offsets using on-the-fly predictions, which uses a sliding window of in-run rates to make predictions. (3) Xmon operations examples are given. Future work involves further automation of the steps to provide the predictive functions and for alerting shifters.

Thermosensitive liposomes for localized delivery and triggered release of chemotherapy

PubMed Central

Ta, Terence; Porter, Tyrone M.

2016-01-01

Liposomes are a promising class of nanomedicine with the potential to provide site-specific chemotherapy, thus improving the quality of cancer patient care. First-generation liposomes have emerged as one of the first nanomedicines used clinically for localized delivery of chemotherapy. Second-generation liposomes, i.e. stimuli-responsive liposomes, have the potential to not only provide site-specific chemotherapy, but also triggered drug release and thus greater spatial and temporal control of therapy. Temperature-sensitive liposomes are an especially attractive option, as tumors can be heated in a controlled and predictable manner with external energy sources. Traditional thermosensitive liposomes are composed of lipids that undergo a gel-to-liquid phase transition at several degrees above physiological temperature. More recently, temperature-sensitization of liposomes has been demonstrated with the use of lysolipids and synthetic temperature-sensitive polymers. The design, drug release behavior, and clinical potential of various temperature-sensitive liposomes, as well as the various heating modalities used to trigger release, are discussed in this review. PMID:23583706

Investigation of Potential Triggered Tremor in Latin America and the Caribbean

NASA Astrophysics Data System (ADS)

Gonzalez-Huizar, H.; Velasco, A. A.; Peng, Z.

2012-12-01

Recent observations have shown that seismic waves generate transient stresses capable of triggering earthquakes and tectonic (or non-volcanic) tremor far away from the original earthquake source. However, the mechanisms behind remotely triggered seismicity still remain unclear. Triggered tremor signals can be particularly useful in investigating remote triggering processes, since in many cases, the tremor pulses are very clearly modulated by the passing surface waves. The temporal stress changes (magnitude and orientation) caused by seismic waves at the tremor source region can be calculated and correlated with tremor pulses, which allows for exploring the stresses involved in the triggering process. Some observations suggest that triggered and ambient tremor signals are generated under similar physical conditions; thus, investigating triggered tremor might also provide important clues on how and under what conditions ambient tremor signals generate. In this work we present some of the results and techniques we employ in the research of potential cases of triggered tectonic tremor in Latin America and the Caribbean. This investigation includes: (1) the triggered tremor detection, with the use of specific signal filters; (2) localization of the sources, using uncommon techniques like time reversal signals; (3) and the analysis of the stress conditions under which they are generated, by modeling the triggering waves related dynamic stress. Our results suggest that tremor can be dynamically triggered by both Love and Rayleigh waves and in broad variety of tectonic environments depending strongly on the dynamic stress amplitude and orientation. Investigating remotely triggered seismicity offers the opportunity to improve our knowledge about deformation mechanisms and the physics of rupture.

Effect of non-alcoholic fatty liver disease on carotid artery intima-media thickness as a risk factor for atherosclerosis

PubMed Central

Nahandi, Maryam Zaare; Ramazanzadeh, Elham; Abbaszadeh, Leili; Javadrashid, Reza; Shirazi, Koorosh Masnadi; Gholami, Nasrin

2014-01-01

Aim This study aimed to evaluate the effect of NAFLD on CIMT as a risk factor for atherosclerosis. Background The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide due to rise of obesity and diabetes mellitus (DM) prevalence. Non-invasive assessment of carotid intima-media thickness (CIMT) by high-resolution carotid B-mode ultrasonography is widely used for determining the atherosclerosis. Patients and methods In this case-control setting, 151 subjects were categorized in three groups: group I including 49 patients with NAFLD and DM; group II including 50 non-diabetic NAFLD patients; and the control including 52 normal subjects as group III. The right and left CIMTs and its maximum reading (CIMTmax) were measured by a skilled sonographist blind to the groups. The sonographic grading of the NAFLD was determined in group I and II. Results Median CIMTmax was significantly higher in group I comparing with group II and control group (p<0.001). This difference between group I and group II was not significant after adjusting for age and history of hypertension and hyperlipidemia (p=0.089). After controlling the confounders, there was statistical significant between group I and group II with the control group (p<0.05). There was no significant difference in median maximal thickness of intima-media in the carotid of group I compare to group II in patients with and without elevated liver enzymes (in both groups, 0.6 mm, p= 0.402). Conclusion Based on our findings, there is a significant association between the presence of NAFLD and atherosclerosis. This association was independent to the DM presence. The grade of NAFLD and elevated liver function tests had no effect on severity of atherosclerosis. PMID:25436098

Diminished heart rate reactivity to acute psychological stress is associated with enhanced carotid intima-media thickness through adverse health behaviors.

PubMed

Ginty, Annie T; Williams, Sarah E; Jones, Alexander; Roseboom, Tessa J; Phillips, Anna C; Painter, Rebecca C; Carroll, Douglas; de Rooij, Susanne R

2016-06-01

Recent evidence demonstrates that individuals with low heart rate (HR) reactions to acute psychological stress are more likely to be obese or smokers. Smoking and obesity are established risk factors for increased carotid intima-media thickness (IMT). The aim of this study was to examine the potential pathways linking intima-media thickness, smoking, body mass index (BMI), and HR stress reactivity. A total of 552 participants, 47.6% male, M (SD) age = 58.3 (0.94) years, were exposed to three psychological stress tasks (Stroop, mirror drawing, and speech) preceded by a resting baseline period; HR was recorded throughout. HR reactivity was calculated as the average response across the three tasks minus average baseline HR. Smoking status, BMI, and IMT were determined by trained personnel. Controlling for important covariates (e.g., socioeconomic status), structural equation modeling revealed that BMI and smoking mediated the negative relationship between HR reactivity and IMT. The hypothesized model demonstrated a good overall fit to the data, χ(2) (8) = 0.692, p = .403; CFI = 1.00; TLI = 1.00 SRMR = .01; RMSEA < .001 (90% CI < 0.01-0.11). HR reactivity was negatively related to BMI (β = -.16) and smoking (β = -.18), and these in turn were positively associated with IMT (BMI: β = .10; smoking: β = .17). Diminished HR stress reactivity appears to be a marker for enlarged IMT and appears to be exerting its impact through already established risks. Future research should examine this relationship longitudinally and aim to intervene early. © 2016 Society for Psychophysiological Research.

Light and electron microscopy study of the spermatheca of Eupholidoptera chabrieri bimucronata (Ramme, 1927) and Uromenus brevicollis trinacriae La Greca 1964 (Orthoptera: Tettigoniidae).

PubMed

Viscuso, Renata; Camiolo, Giuseppina; Vitale, Danilo G M

2015-07-01

A study by both optical and electron microscopy has been carried out on the spermatheca of Eupholidoptera chabrieri bimucronata and Uromenus brevicollis trinacriae (Orthoptera: Tettigoniidae). In both the examined species, the spermatheca consists of a sac/kidney-shaped seminal receptacle and a more or less tortuous spermathecal duct that opens into the common oviduct. The wall of both the organs consists of a pseudostratified epithelium surmounted by a cuticular intima; the latter is made up of a thicker endocuticle and an epicuticle. The epithelium shows two different cell types, irregularly arranged and with well differentiated functions: cuticle-forming and gland cells. In both the species, the cuticle-forming cells perform other functions, in addition to producing the cuticular intima. The gland cells never come in contact with the cuticular intima, have inside the reservoir a secretion whose appearance can diversify also in contiguous zones of the seminal receptacle. Based on our findings in both the species, the functions of the seminal receptacle would differ from those of the spermathecal duct. In the latter, some areas of the wall of the connecting tract show an activity of lysis, by contiguous epithelial cells, that could play a role in control and selection of spermatozoa. As for the feather-shaped spermatodesms, similar in both the species, freeze-fracture observations have shown that the acrosome of each spermatozoon regularly covers three-quarters of the extension of the acrosome of the following spermatozoon. Finally, the significance of our findings, compared with what is known in literature, is discussed. © 2015 Wiley Periodicals, Inc.

The Effect of Sitagliptin on the Regression of Carotid Intima-Media Thickening in Patients with Type 2 Diabetes Mellitus: A Post Hoc Analysis of the Sitagliptin Preventive Study of Intima-Media Thickness Evaluation.

PubMed

Mita, Tomoya; Katakami, Naoto; Shiraiwa, Toshihiko; Yoshii, Hidenori; Gosho, Masahiko; Shimomura, Iichiro; Watada, Hirotaka

2017-01-01

Background. The effect of dipeptidyl peptidase-4 (DPP-4) inhibitors on the regression of carotid IMT remains largely unknown. The present study aimed to clarify whether sitagliptin, DPP-4 inhibitor, could regress carotid intima-media thickness (IMT) in insulin-treated patients with type 2 diabetes mellitus (T2DM). Methods . This is an exploratory analysis of a randomized trial in which we investigated the effect of sitagliptin on the progression of carotid IMT in insulin-treated patients with T2DM. Here, we compared the efficacy of sitagliptin treatment on the number of patients who showed regression of carotid IMT of ≥0.10 mm in a post hoc analysis. Results . The percentages of the number of the patients who showed regression of mean-IMT-CCA (28.9% in the sitagliptin group versus 16.4% in the conventional group, P  = 0.022) and left max-IMT-CCA (43.0% in the sitagliptin group versus 26.2% in the conventional group, P  = 0.007), but not right max-IMT-CCA, were higher in the sitagliptin treatment group compared with those in the non-DPP-4 inhibitor treatment group. In multiple logistic regression analysis, sitagliptin treatment significantly achieved higher target attainment of mean-IMT-CCA ≥0.10 mm and right and left max-IMT-CCA ≥0.10 mm compared to conventional treatment. Conclusions . Our data suggested that DPP-4 inhibitors were associated with the regression of carotid atherosclerosis in insulin-treated T2DM patients. This study has been registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000007396).

Erectile dysfunction, metabolic syndrome and arterial disease. Clinical-pathological relation by carotid ultrasonography.

PubMed

Arrabal-Polo, M A; Vera-Arroyo, B; Lahoz-García, C; Valderrama-Illana, P; Cámara-Ortega, M; Arrabal-Martín, M; Zuluaga-Gomez, A; Lopez-Carmona Pintado, F

2014-04-01

Different studies have shown the relationship between erectile dysfunction, metabolic syndrome and cardiovascular disease. The objective of this study was to evaluate the presence of arteriopathy performing carotid ultrasound in patients with and without erectile dysfunction. We conducted a case-control study with 44 patients consulting for erectile dysfunction and 20 controls. All subjects completed the IIEF-5 test and we studied the criteria for metabolic syndrome, and a carotid ultrasound to study the intima-media thickness and the presence of atherosclerotic plaques was performed. Mean intima-media thickness was .71mm±.21 for the right and of .71±.17 for the left carotid in patients with erectile dysfunction. In the control group, the means were .54±0.11 and 0.59±0.15mm respectively, statistically significant differences (P=.02 and P=.05 respectively). No plaque was found in any control, but in 25% of both carotid arteries of patients with erectile dysfunction (P=.01). As metabolic syndrome, according to the American Heart Association, were diagnosed 52.8% of patients with erectile dysfunction, and 16.7% of controls, and according to the International Diabetes Federation, 52.3% of patients with erectile dysfunction and 25% of controls met diagnostic criteria. In both cases there were significant differences (P<.01 and P=.02 respectively). We found a positive linear correlation between waist circumference and the intima-media thickness in both carotid (P<.05). Patients with erectile dysfunction may be at increased risk of cardiovascular disease, as determined by the presence of arterial disease in the carotid arteries, which indicates that we should made a more thorough and comprehensive study of patients with erectile dysfunction. Copyright © 2013 AEU. Published by Elsevier Espana. All rights reserved.

Association Between Macrominerals Intake and Changes in Internal Carotid Artery-Intima Media Thickness in POST Ischemic Stroke Patients

NASA Astrophysics Data System (ADS)

Pudjonarko, Dwi; Tugasworo, Dodik; Silaen, Rumintang

2017-02-01

Carotid Intima Media Thickness (C-IMT) has been widely used as marker for atherosclerosis. Previous studies on minerals intake and its association with C-IMT revealed various. Most of the studies showed inconsistent results. The aim of this study is to determine wether macro minerals intake is related to internal carotid-intima media thickness (IC-IMT). This is a longitudinal study, pre test post test design conducted in Neurology clinic, Kariadi hospital, Semarang from June to December 2014. Subjects were 22 post ischemic stroke patients. Minerals intake and IC-IMT was measured using Food Frequency Questionnaire and Duplex Carotid Ultrasonography. Statistical analysis was performed using Chi-Square, Fisher Exact and Logistic Regression test. Subjects included in this study were 17 male subjects (77.3%) and 5 female subjects (22.7%). Mean of IC-IMT in female subjects was found to be higher than in male. Mean of total IC-IMT was increased after a period of six months (0.96±0.80 to 0.97±0.21 mm). There were significant association between calcium as well as sodium intakes and IC-IMT. In contrast, there were no association between magnesium as well as potassium intake and IC-IMT. Multivariate analysis suggest that sodium intake (OR=26.828) was the most influencing factor for IC-IMT, followed by calcium intake (OR=0.042). Calcium as well as potassium intake were independently associated with IC-IMT. Magnecium as well as sodium intake were not independently associated with IC-IMT changes. Sodium intake was the most influencing variable to IC-IMT changes, followed by calcium intake.

Effect of acarbose to delay progression of carotid intima-media thickness in early diabetes.

PubMed

Patel, Y R; Kirkman, M S; Considine, R V; Hannon, T S; Mather, K J

2013-10-01

The anti-diabetic agent acarbose reduces postprandial glucose excursions. We have evaluated the effect of randomized treatment with acarbose on the progression of carotid intima-media thickness (IMT) in early diabetes. The Early Diabetes Intervention Program was a randomized trial of acarbose versus placebo in 219 participants with early diabetes characterized by glucose values over 11.1 mmol/L 2 h after a 75 g oral glucose load and a mean HbA1c of 6.3%. IMT was measured at baseline and yearly. Follow-up was discontinued if participants progressed to the study glucose endpoints; IMT readings were available for a median of 2 years, with 72 subjects followed for 5 years. Progressive increases in IMT were seen in both treatment groups, but progression was reduced in participants randomized to acarbose (p = 0.047). In age, sex and smoking-adjusted analyses, IMT progression was associated with greater fasting and oral glucose tolerance test-excursion glucose, fasting insulin, cholesterol and glycated low-density lipoprotein concentrations. IMT progression was reduced with study-related changes in weight, insulin and non-esterified fatty acids; these features were more strongly associated with reduced IMT progression than acarbose treatment. Despite strong associations of baseline glycemia with IMT progression, study-related changes in glucose were not important determinants of IMT progression. Acarbose can delay progression of carotid intima-media thickness in early diabetes defined by an oral glucose tolerance test. Glucose, weight, insulin and lipids contributed to risk of progression but reductions in glycemia were not major determinants of reduced rate of IMT progression. Vascular benefits of acarbose may be independent of its glycemic effects. Copyright © 2013 John Wiley & Sons, Ltd.

Effects of Acarbose to Delay Progression of Carotid Intima-Media Thickness in Early Diabetes

PubMed Central

Patel, YR; Kirkman, MS; Considine, RV; Hannon, TS; Mather, KJ

2014-01-01

Background The antidiabetic agent acarbose reduces postprandial glucose excursions. We have evaluated the effect of randomized treatment with acarbose on the progression of carotid intima-media thickness (IMT) in early diabetes. Methods The Early Diabetes Intervention Program (EDIP) was a randomized trial of acarbose versus placebo, in 219 participants with early diabetes characterized by glucose values over 11.1 mmol/L 2 hours after a 75g oral glucose load, and mean HbA1c 6.3%. IMT was measured at baseline and yearly. Follow-up was discontinued if participants progressed to the study glucose endpoints; IMT readings were available for a median of 2 years, with 72 subjects followed for 5 years. Results Progressive increases in IMT were seen in both treatment groups, but this was reduced in participants randomized to acarbose (p=0.047). In age, sex and smoking-adjusted analyses IMT progression was associated with greater fasting and OGTT-excursion glucose, fasting insulin, cholesterol, and glycated LDL concentrations. IMT progression was reduced with study-related changes in weight, insulin, and nonesterified fatty acids; these features were more strongly associated with reduced IMT progression than acarbose treatment. Despite strong associations of baseline glycemia with IMT progression, study-related changes in glucose were not important determinants of IMT progression. Conclusions Acarbose can delay progression of carotid intima-media thickness in early diabetes defined by an oral glucose tolerance test. Glucose, weight, insulin and lipids contributed to risk of progression but reductions in glycemia were not major determinants of reduced rate of IMT progression. Vascular benefits of acarbose may be independent of its glycemic effects. PMID:23908125

Migration of mononuclear cells expressing β-actin through the adventitia into media and intima in coronary arteriogenesis and venogenesis in ischemic myocardium.

PubMed

Uchida, Yasuto; Uchida, Yasumi; Maezawa, Yoshiro; Maezawa, Yuko; Tabata, Tsuyoshi

2012-01-01

It was previously thought that arteriogenesis and venogenesis are induced not only by proliferation of vessel-resident smooth muscle cells (SMCs) and endothelial cells (ECs) but also by migration of their precursors. However, it is not well understood through what route(s) the precursors migrate into the existing vessels.We examined through what route or routes circulating mononuclear cells expressing β-actin (β-MNCs), which we identified in canine coronary vessels, migrate into coronary vessel walls and cause arteriogenesis and venogenesis at 1, 2, 4 and 8 weeks after induction of myocardial infarction.The following changes were observed: (1) The β-MNCs migrated via coronary microvessels to the interstitial space at one week; (2) β-MNCs traversed the adventitia into the media and settled in parallel with pre-existing smooth muscle cells (SMCs) in arterioles and arteries and lost β-actin and acquired α-smooth muscle actin (α-SMA) to become mature SMCs at 2-4 weeks; (3) at the same time, other β-MNCs migrated across the adventitia and media into the intima and settled in parallel with pre-existing endothelial cells (ECs) and lost β-actin, while acquiring CD(31), to become mature ECs, resulting in arteriogenesis; (4) Similarly, β-MNCs migrated into venular and venous walls and became SMCs or ECs, resulting in venogenesis.β-MNCs in the interstitial space expressed CD(34) but not other major vascular cell markers.β-MNCs, possibly a vascular progenitor, migrate not from the lumen but across the adventitia into the media or intima of coronary vessels and transit to SMCs or ECs, and participate in arteriogenesis and venogenesis in ischemic myocardium.

Apoptosis, cell proliferation and modulation of cyclin-dependent kinase inhibitor p21cip1 in vascular remodelling during vein arterialization in the rat

PubMed Central

Borin, Thaiz Ferraz; Miyakawa, Ayumi Aurea; Cardoso, Leandro; de Figueiredo Borges, Luciano; Gonçalves, Giovana Aparecida; Krieger, Jose Eduardo

2009-01-01

Neo-intima development and atherosclerosis limit long-term vein graft use for revascularization of ischaemic tissues. Using a rat model, which is technically less challenging than smaller rodents, we provide evidence that the temporal morphological, cellular, and key molecular events during vein arterialization resemble the human vein graft adaptation. Right jugular vein was surgically connected to carotid artery and observed up to 90 days. Morphometry demonstrated gradual thickening of the medial layer and important formation of neo-intima with deposition of smooth muscle cells (SMC) in the subendothelial layer from day 7 onwards. Transmission electron microscopy showed that SMCs switch from the contractile to synthetic phenotype on day 3 and new elastic lamellae formation occurs from day 7 onwards. Apoptosis markedly increased on day 1, while α-actin immunostaining for SMC almost disappeared by day 3. On day 7, cell proliferation reached the highest level and cellular density gradually increased until day 90. The relative magnitude of cellular changes was higher in the intima vs. the media layer (100 vs. 2 times respectively). Cyclin-dependent kinase inhibitors (CDKIs) p27Kip1 and p16INKA remained unchanged, whereas p21Cip1 was gradually downregulated, reaching the lowest levels by day 7 until day 90. Taken together, these data indicate for the first time that p21Cip1 is the main CDKI protein modulated during the arterialization process the rat model of vein arterialization that may be useful to identify and validate new targets and interventions to improve the long-term patency of vein grafts. PMID:19563615

The sequence of prenatal growth restraint and post-natal catch-up growth leads to a thicker intima-media and more pre-peritoneal and hepatic fat by age 3-6 years.

PubMed

Sebastiani, G; Díaz, M; Bassols, J; Aragonés, G; López-Bermejo, A; de Zegher, F; Ibáñez, L

2016-08-01

Infants born small-for-gestational-age (SGA) who develop post-natal weight catch-up are at risk for insulin resistance, central adiposity and cardiovascular disease in later life, even in the absence of overweight. In young (age 3-6 years) non-obese SGA children, we assessed arterial health (as judged by intima-media thickness [IMT]) and abdominal fat distribution (subcutaneous, visceral, preperitoneal and hepatic components by magnetic resonance imaging [MRI] and/or ultrasound [US]) besides a selection of endocrine markers. Comparisons of measures in SGA (n = 27) vs. appropriate-for-GA (AGA) children (n = 19) of similar height, weight and body mass index. Longitudinal outcomes (age 3-6 years) were carotid IMT (cIMT); fasting glucose, circulating insulin, IGF-I and high-molecular-weight (HMW) adiponectin; abdominal fat partitioning by US. Cross-sectional outcomes (age 6 years) were aortic IMT (aIMT) and abdominal fat partitioning by MRI. At 3 and 6 years, cIMT and IGF-I results were higher and HMW adiponectin lower in SGA than AGA children; at 6 years, SGA subjects had also a thicker aIMT and more pre-peritoneal and hepatic fat, and were less insulin sensitive (all P values between <0.05 and <0.0001). cIMT correlated positively with pre-peritoneal fat, particularly at 6 years. Post-SGA status and weight gain in early childhood (between 3 and 6 years) were independent predictors of cIMT at 6 years, explaining 48 % of its variance. SGA children aged 3-6 years were found to have a thicker intima- media and more pre-peritoneal and hepatic fat than AGA children of comparable size. © 2015 World Obesity.

Cardiovascular Risk Factors in Cluster Headache.

PubMed

Lasaosa, S Santos; Diago, E Bellosta; Calzada, J Navarro; Benito, A Velázquez

2017-06-01

 Patients with cluster headache tend to have a dysregulation of systemic blood pressure such as increased blood pressure variability and decreased nocturnal dipping. This pattern of nocturnal nondipping is associated with end-organ damage and increased risk of cardiovascular disease.  To determine if cluster headache is associated with a higher risk of cardiovascular disease.  Cross-sectional study of 33 cluster headache patients without evidence of cardiovascular disease and 30 age- and gender-matched healthy controls. Ambulatory blood pressure monitoring was performed in all subjects. We evaluate anthropometric, hematologic, and structural parameters (carotid intima-media thickness and ankle-brachial index).  Of the 33 cluster headache patients, 16 (48.5%) were nondippers, a higher percentage than expected. Most of the cluster headache patients (69.7%) also presented a pathological ankle-brachial index. In terms of the carotid intima-media thickness values, 58.3% of the patients were in the 75th percentile, 25% were in the 90th percentile, and 20% were in the 95th percentile. In the control group, only five of the 30 subjects (16.7%) had a nondipper pattern ( P  =   0.004), with 4.54% in the 90th and 95th percentiles ( P  =   0.012 and 0.015).  Compared with healthy controls, patients with cluster headache presented a high incidence (48.5%) of nondipper pattern, pathological ankle-brachial index (69.7%), and intima-media thickness values above the 75th percentile. These findings support the hypothesis that patients with cluster headache present increased risk of cardiovascular disease. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Effect of periodontal therapy on arterial structure and function among aboriginal australians: a randomized, controlled trial.

PubMed

Kapellas, Kostas; Maple-Brown, Louise J; Jamieson, Lisa M; Do, Loc G; O'Dea, Kerin; Brown, Alex; Cai, Tommy Y; Anstey, Nicholas M; Sullivan, David R; Wang, Hao; Celermajer, David S; Slade, Gary D; Skilton, Michael R

2014-10-01

Observational studies and nonrandomized trials support an association between periodontal disease and atherosclerotic vascular disease. Both diseases occur frequently in Aboriginal Australians. We hypothesized that nonsurgical periodontal therapy would improve measures of arterial function and structure that are subclinical indicators of atherosclerotic vascular disease. This parallel-group, randomized, open label clinical trial enrolled 273 Aboriginal Australians aged ≥18 years with periodontitis. Intervention participants received full-mouth periodontal scaling during a single visit, whereas controls received no treatment. Prespecified primary end points measured 12-month change in carotid intima-media thickness, an indicator of arterial structure, and 3- and 12-month change in pulse wave velocity, an indicator of arterial function. ANCOVA used complete case data to evaluate treatment group differences. End points could be calculated for 169 participants with follow-up data at 3 months and 168 participants at 12 months. Intima-media thickness decreased significantly after 12 months in the intervention group (mean reduction=-0.023 [95% confidence interval {CI}, -0.038 to -0.008] mm) but not in the control group (mean increase=0.002 [95% CI, -0.017 to 0.022] mm). The difference in intima-media thickness change between treatment groups was statistically significant (-0.026 [95% CI, -0.048 to -0.003] mm; P=0.03). In contrast, there were no significant differences between treatment groups in pulse wave velocity at 3 months (mean difference, 0.06 [95% CI, -0.17 to 0.29] m/s; P=0.594) or 12 months (mean difference, 0.21 [95% CI, -0.01 to 0.43] m/s; P=0.062). Periodontal therapy reduced subclinical arterial thickness but not function in Aboriginal Australians with periodontal disease, suggesting periodontal disease and atherosclerosis are significantly associated. © 2014 American Heart Association, Inc.

Association between carotid intima-media thickness, buccodental status, and glycemic control in pediatric type 1 diabetes.

PubMed

Gómez-Díaz, Rita A; Ramírez-Soriano, Eleazar; Tanus Hajj, Janet; Bautista Cruz, Elia; Jiménez Galicia, Cesar; Villasis-Keever, Miguel Angel; Aguilar-Salinas, Carlos A; Wacher, Niels H

2012-11-01

To evaluate the association between carotid intima-media thickness, buccodental status, and glycemic control in patients with type 1 diabetes. Cross-sectional study with consecutive cases attended in an outpatient clinic (n = 69). Medical and clinical dental history, HbA1c, lipid profile, treatment period, and daily insulin dosage were recorded. Sociodemographic data and anthropometrical measurements were obtained by standardized questionnaire. Doppler real-time ultrasound was performed by a single experienced vascular radiologist blinded to the study. Assessment of buccodental status was done by the Maxillofacial Unit of the Pediatrics Hospital, and an oral scrape culture was collected. The mean age was 11.7 ± 3.0 years, with diabetes 5.1 ± 3.3 years. Mean HbA1c was 8.5 ± 1.7%. Primary teeth were present in 52.2% and bacterial plaque in 94.2%. Buccodental conditions featured caries (63.8%), gingivitis (84%), and enamel demineralization (26.1%): white spot lesions (18.8%) and cavitated lesions (7.3%). Bacteria associated with caries were found in 44.1%. Patients in the highest HbA1c tertile (>8.5%) had greater frequency of buccodental conditions and were positive for Streptococcus mutans and Candida albicans; also, cIMT increased and vessel compliance decreased compared to those in the lowest tertile (<7.0%) (p < 0.05). More buccodental conditions and carotid intima-media thickness increase appeared in the patients with HbA1c level > 8.5%, suggesting onset of atherosclerosis. The correlation between buccodental status and HbA1c values may indicate the connection between inflammatory states of atherosclerosis and type 1 diabetes. © 2012 John Wiley & Sons A/S.

Fenestral pore size in the internal elastic lamina affects transmural flow distribution in the artery wall.

PubMed

Tada, S; Tarbell, J M

2001-06-01

Interstitial flow through the subendothelial intima and media of an artery wall was simulated numerically to investigate the water flow distribution through fenestral pores which affects the wall shear stress on smooth muscle cells right beneath the internal elastic lamina (IEL). A two-dimensional analysis using the Brinkman model of porous media flow was performed. It was observed that the hydraulic permeability of the intimal layer should be much greater than that of the media in order to predict a reasonable magnitude for the pressure drop across the subendothelial intima and IEL (about 23 mostly at a 70 mm Hg luminal pressure). When Ki was set equal to the value in the media, this pressure drop was unrealistically high. Furthermore, the higher value of Ki produced a nearly uniform distribution of water flow through a simple array of fenestral pores all having the same diameters (1.2 microm), whereas when Ki was set at the value in the media, the flow distribution through fenestral pores was highly nonuniform and nonphysiologic. A deformable intima model predicted a nonuniform flow distribution at high pressure (180 mm Hg). Damage to the IEL was simulated by introducing a large fenestral pore (up to 17.8 microm) into the array. A dramatic increase in flow through the large pore was observed implying an altered fluid mechanical environment on the smooth muscle cells near the large pore which has implications for intimal hyperplasia and atherosclerosis. The model also predicted that the fluid shear stress on the bottom surface of an endothelial cell is on the order of 10 dyne/cm2, a level which can affect cell function.

Long-term Saxagliptin Treatment Improves Endothelial Function but not Pulse Wave Velocity and Intima-Media Thickness in Type 2 Diabetic Patients.

PubMed

Dell'Oro, Raffaella; Maloberti, Alessandro; Nicoli, Francesco; Villa, Paolo; Gamba, Pierluigi; Bombelli, Michele; Mancia, Giuseppe; Grassi, Guido

2017-12-01

Pharmacological inhibition of dipeptidyl-peptidase-4 may represent a promising therapeutic approach for glucose control and vascular protection. No information is available on the effects of saxagliptin (S) on aortic pulse wave velocity, carotid intima-media thickness and flow-mediated dilation (FMD, brachial artery) in diabetes. We investigated the long-term effects of S, as add-on therapy to metformin, on the above mentioned variables. In 16 patients with decompensated diabetes aortic pulse wave velocity, carotid intima-media thickness and FMD, office and 24-h ambulatory blood pressure, anthropometric, biochemical and metabolic parameters were measured at baseline and after 6 and 12 months of treatment. A group of 16 compensated diabetics served as controls. The two groups showed superimposable values of the different parameters, with the exception of glycated hemoglobin, blood glucose significantly (P < 0.05) greater in the S-treated patients. In the S-group glucose metabolism and FMD significantly improved during the follow-up (from 169.3 ± 8 to 157.1 ± 9 mg/dl, P < 0.05, from 7.9 ± 0.1 to 6.9 ± 0.2%, P < 0.001 and from 3.6 ± 0.3 to 7.4 ± 0.8%, respectively P < 0.05). No significant difference was detected in the other parameters, including blood pressure. Thus treatment with S added-on to metformin results in beneficial effects on endothelial function, related at least in part to the concomitant improvement in glucose metabolism. This may represent a first step in the chain of events leading to a reduction in the progression of the vascular atherogenic process.

Contrast-enhanced ultrasonography vs B-mode ultrasound for visualization of intima-media thickness and detection of plaques in human carotid arteries.

PubMed

Shah, Benoy N; Chahal, Navtej S; Kooner, Jaspal S; Senior, Roxy

2017-05-01

Carotid intima-media thickness (IMT) and plaque are recognized markers of increased risk for cerebrovascular events. Accurate visualization of the IMT and plaques is dependent upon image quality. Ultrasound contrast agents improve image quality during echocardiography-this study assessed whether contrast-enhanced ultrasound (CEUS) improves carotid IMT visualization and plaque detection in an asymptomatic population. Individuals free from known cardiovascular disease, enrolled in a community study, underwent B-mode and CEUS carotid imaging. Each carotid artery was divided into 10 segments (far and near walls of the proximal, mid and distal segments of the common carotid artery, the carotid bulb, and internal carotid artery). Visualization of the IMT complex and plaque assessments was made during both B-mode and CEUS imaging for all enrolled subjects, a total of 175 individuals (mean age 65±9 years). Visualization of the IMT was significantly improved during CEUS compared with B-mode imaging, in both near and far walls of the carotid arteries (% IMT visualization during B-mode vs CEUS imaging: 61% vs 94% and 66% vs 95% for right and left carotid arteries, respectively, P<.001 for both). Additionally, a greater number of plaques were detected during CEUS imaging compared with B-mode imaging (367 plaques vs 350 plaques, P=.02). Contrast-enhanced ultrasound improves visualization of the intima-media complex, in both near and far walls, of the common and internal carotid arteries and permits greater detection of carotid plaques. Further studies are required to determine whether there is incremental clinical and prognostic benefit related to superior plaque detection by CEUS. © 2017, Wiley Periodicals, Inc.

Carotid atherosclerosis and right ventricular diastolic dysfunction in a sample of hypertensive Nigerian patients

PubMed Central

Akintunde, Adeseye A.; Adebayo, Philip B.; Aremu, Ademola A.; Opadijo, Oladimeji G.

2013-01-01

Aim To determine the association of carotid atherosclerosis and right ventricular diastolic dysfunction (DD) among treated hypertensive Nigerian patients. Methods This was a single center cross-sectional study performed at the Cardiology Clinic of LAUTECH Teaching Hospital, Ogbomoso, Nigeria between January and December 2012. The study included 122 hypertensive Nigerians (mean age, 57.3 ± 14.7 years, 36.9% women). Patients’ clinical, demographic, and echocardiographic parameters were obtained. Diastolic dysfunction was assessed with the trans-tricuspid Doppler flow. Results Patients with DD were significantly older than those with normal diastolic function. Mean and maximum carotid intima media thickness measurements were significantly higher among patients with right ventricular DD than in those with normal diastolic function. Mean systolic blood pressure (148.3 ± 31.9 vs 128.0 ± 2.8 mm Hg, P = 0.049) and interventricular septal thickness in diastole (12.8 ± 2.3 vs 11.6 ± 2.8mm, P = 0.048) were significantly higher and tricuspid annular pulmonary systolic excursion (33.6 ± 4.9 vs 23.0 ± 4.2 mm, P = 0.035) was significantly lower in patients with right ventricular DD than in those with normal diastolic function. Carotid intima media thickness measurements were correlated with early trans-tricuspid Doppler flow and early transtricuspid diastolic flow/late right atrial transtricupsid diastolic flow ratio. Conclusion Right ventricular DD in hypertensive patients was significantly correlated with increased carotid atherosclerosis. Carotid intima media thickness measurements may therefore be a surrogate marker for DD in hypertensive subjects. PMID:24382850

Ankle-brachial index and its link to automated carotid ultrasound measurement of intima-media thickness variability in 500 Japanese coronary artery disease patients.

PubMed

Ikeda, Nobutaka; Araki, Tadashi; Sugi, Kaoru; Nakamura, Masatako; Deidda, Martino; Molinari, Filippo; Meiburger, Kristen M; Acharya, U Rajendra; Saba, Luca; Bassareo, Pier Paolo; Di Martino, Michele; Nagashima, Yoshinori; Mercuro, Giuseppe; Nakano, Masataka; Nicolaides, Andrew; Suri, Jasjit S

2014-03-01

The purpose of this study was to evaluate whether the carotid intima-media thickness (cIMT) and intima-media thickness variability (IMTV) along the artery are correlated to the ankle-brachial index (ABI) in Japanese coronary artery disease patients. Five hundred consecutive patients (312 males; median age 69 ± 11 years) who underwent carotid ultrasonography and first coronary angiography were prospectively analyzed. By using automated software (AtheroEdge™, AtheroPoint, Roseville, CA, USA), we obtained the cIMT and IMTV. Pearson correlation analysis was performed to calculate the association between ABI, automatically measured cIMT, automatically measured IMTV, and the SYNTAX score. The mean cIMT was 0.881 ± 0.334 mm and the mean IMTV was 0.141 ± 0.112. IMTV was negatively and significantly correlated to ABI (ρ = -0.147; p = 0.001), whereas cIMT was not (ρ = -0.075; p = 0.097). IMTV and cIMT had the same significant correlation with the SYNTAX score. When we considered patients with a higher risk factor (ABI ≤ 0.9), we found higher values of IMTV and the SYNTAX score, but not higher values of cIMT. Logistic regression analysis showed that IMTV was independently associated with the complexity of the coronary artery disease (as assessed by the SYNTAX score). In conclusion, we show that IMTV automatically measured using AtheroEdge™ was correlated with ABI, whereas cIMT was not. IMTV could be integrated with cIMT measurement to improve the assessment of cardiovascular disease.

Dynamic triggering of low magnitude earthquakes in the Middle American Subduction Zone

NASA Astrophysics Data System (ADS)

Escudero, C. R.; Velasco, A. A.

2010-12-01

We analyze global and Middle American Subduction Zone (MASZ) seismicity from 1998 to 2008 to quantify the transient stresses effects at teleseismic distances. We use the Bulletin of the International Seismological Centre Catalog (ISCCD) published by the Incorporated Research Institutions for Seismology (IRIS). To identify MASZ seismicity changes due to distant, large (Mw >7) earthquakes, we first identify local earthquakes that occurred before and after the mainshocks. We then group the local earthquakes within a cluster radius between 75 to 200 km. We obtain statistics based on characteristics of both mainshocks and local earthquakes clusters, such as local cluster-mainshock azimuth, mainshock focal mechanism, and local earthquakes clusters within the MASZ. Due to lateral variations of the dip along the subducted oceanic plate, we divide the Mexican subduction zone in four segments. We then apply the Paired Samples Statistical Test (PSST) to the sorted data to identify increment, decrement or either in the local seismicity associated with distant large earthquakes. We identify dynamic triggering for all MASZ segments produced by large earthquakes emerging from specific azimuths, as well as, a decrease for some cases. We find no depend of seismicity changes due to focal mainshock mechanism.

Rainfall-triggered landslides, anthropogenic hazards, and mitigation strategies

USGS Publications Warehouse

Larsen, M.C.

2008-01-01

Rainfall-triggered landslides are part of a natural process of hillslope erosion that can result in catastrophic loss of life and extensive property damage in mountainous, densely populated areas. As global population expansion on or near steep hillslopes continues, the human and economic costs associated with landslides will increase. Landslide hazard mitigation strategies generally involve hazard assessment mapping, warning systems, control structures, and regional landslide planning and policy development. To be sustainable, hazard mitigation requires that management of natural resources is closely connected to local economic and social interests. A successful strategy is dependent on a combination of multi-disciplinary scientific and engineering approaches, and the political will to take action at the local community to national scale.

"The World in a Drop of Water": The Feminist Vision of Patricia Howell.

ERIC Educational Resources Information Center

Holmlund, Chris

1993-01-01

Discusses two films ("Dos veces mujer" and "Intima raiz") of Patricia Howell. Demonstrates how thoroughly the feminist themes Howell's films weave together around motherhood are inflected by the specific Latin American and Costa Rican contexts in which she works. (RS)

Metabolic and cardiovascular adjustments during psychological stress and carotid artery intima-media thickness in youth

USDA-ARS?s Scientific Manuscript database

Objective: Absolute systolic blood pressure during exercise and a greater increase above baseline, or reactivity, in systolic blood pressure during psychological stress are correlated with an increased risk for cardiovascular disease. Most studies hypothesize that increased cardiovascular responses...

Role of Tissue Transglutaminases in Breast Cancer

DTIC Science & Technology

1999-07-01

TG in re- epithelialization and keratinization, as reported by others (34). Raghunath et al found that TG was expressed at the dermo-epidermal...and vascular prosthesis pseudo-intimas. Am J Pathol. 141 (4):861-80. 34. Raghunath , M., Hopfner, B., Aeschlimann, D., Luthi, U., Meuli, M

The relationship between carotid blood pressure reactivity to mental stress and carotid intima-media thickness.

PubMed

Spartano, Nicole L; Augustine, Jacqueline A; Lefferts, Wesley K; Gump, Brooks B; Heffernan, Kevin S

2014-10-01

Brachial blood pressure (BP) reactivity to stress predicts large artery damage and future cardiovascular (CV) events. Central BP is an emerging risk factor associated with target organ damage (TOD). Currently, little is known about the central BP response to mental stress and its association to TOD. Twenty-five healthy, non-obese adults completed a computerized mental stress test. Brachial and carotid systolic (S)BP reactivity to stress were calculated as SBP during stress minus resting SBP. Resting carotid intima-media thickness (IMT) was also measured. Carotid SBP reactivity to stress was significantly associated with carotid IMT, independent of age, sex, body mass index, non-high density lipoprotein cholesterol and brachial SBP reactivity to stress (r = 0.386, p < 0.05). The relationship between carotid SBP reactivity and carotid IMT suggests that the central BP response to stress may prove to be an early risk marker for potential subclinical TOD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Association between smoking status and the parameters of vascular structure and function in adults: results from the EVIDENT study.

PubMed

Recio-Rodriguez, Jose I; Gomez-Marcos, Manuel A; Patino Alonso, Maria C; Martin-Cantera, Carlos; Ibañez-Jalon, Elisa; Melguizo-Bejar, Amor; Garcia-Ortiz, Luis

2013-12-01

The present study analyses the relation between smoking status and the parameters used to assess vascular structure and function. This cross-sectional, multi-centre study involved a random sample of 1553 participants from the EVIDENT study. The smoking status, peripheral augmentation index and ankle-brachial index were measured in all participants. In a small subset of the main population (265 participants), the carotid intima-media thickness and pulse wave velocity were also measured. After controlling for the effect of age, sex and other risk factors, present smokers have higher values of carotid intima-media thickness (p = 0.011). Along the same lines, current smokers have higher values of pulse wave velocity and lower mean values of ankle-brachial index but without statistical significance in both cases. Among the parameters of vascular structure and function analysed, only the IMT shows association with the smoking status, after adjusting for confounders.

[Ultrastructure of the intima of human pial arteries in arterial hypertension].

PubMed

Chertok, V M; Kotsiuba, A E; Babich, E V

2009-01-01

Ultrastructure of the intima of human pial arteries obtained from 5 male cadavers of practically healthy individuals and from 8 cadavers of the patients with the intravitally diagnosed grade I arterial hypertension (AH) was studied by scanning and transmission electron microscopy. AH was found to be associated with the remodeling of the intimal structural elements in the pial arteries. In most arteries, the changes were detected in the microrelief of the luminal surface and in the permeability of the vascular endothelial lining and of the subendothelial layer. During this remodeling, some endothelial cells were found in the state of structural and functional adaptation to the elevated arterial pressure, while the others were undergoing the dystrophic changes. The latter include the cells containing lipid inclusions, as well as the endothelial cells presumably in the state of apoptosis. The destruction of the intercellular junctions, the disturbances in the endothelium permeability contributed to the development of subendothelial layer edema, resulting in its significant thickening. This layer became looser and contained abundant collagen fibrils.

Association between smoking status and the parameters of vascular structure and function in adults: results from the EVIDENT study

PubMed Central

2013-01-01

Background The present study analyses the relation between smoking status and the parameters used to assess vascular structure and function. Methods This cross-sectional, multi-centre study involved a random sample of 1553 participants from the EVIDENT study. Measurements: The smoking status, peripheral augmentation index and ankle-brachial index were measured in all participants. In a small subset of the main population (265 participants), the carotid intima-media thickness and pulse wave velocity were also measured. Results After controlling for the effect of age, sex and other risk factors, present smokers have higher values of carotid intima-media thickness (p = 0.011). Along the same lines, current smokers have higher values of pulse wave velocity and lower mean values of ankle-brachial index but without statistical significance in both cases. Conclusions Among the parameters of vascular structure and function analysed, only the IMT shows association with the smoking status, after adjusting for confounders. PMID:24289208

Carotid intima-media thickness: ultrasound measurement, prognostic value and role in clinical practice.

PubMed

Nair, Satheesh Balakrishnan; Malik, Rayaz; Khattar, Rajdeep S

2012-12-01

Ultrasound measurement of carotid intima-media thickness (IMT) has become a valuable tool for detecting and monitoring progression of atherosclerosis and recently published recommendations provide guidance for proper standardisation of these measurements. Important determinants of carotid IMT include age, gender, systolic blood pressure, diabetes mellitus and serum cholesterol levels. Many studies have shown carotid IMT to correlate with the severity of coronary atherosclerosis assessed by CT coronary calcification scores, coronary angiography and intravascular ultrasound. Consistent with its correlation with cardiovascular risk factors and coronary artery disease, a meta-analysis of large observational studies has shown carotid IMT to be a strong predictor of future cardiovascular events. Moreover, in patients with established coronary artery disease a reduction in carotid IMT has been shown to translate into a reduction in future cardiovascular events. Consensus statements now also recommend carotid IMT measurements to further refine the prognostic assessment of patients traditionally considered to be at an intermediate risk of cardiovascular disease.

NIR‐Triggered Crystal Phase Transformation of NiTi‐Layered Double Hydroxides Films for Localized Chemothermal Tumor Therapy

PubMed Central

Wang, Donghui; Ge, Naijian; Yang, Tingting; Peng, Feng; Qiao, Yuqin; Li, Qianwen

2018-01-01

Abstract Construction of localized drug‐eluting systems with synergistic chemothermal tumor‐killing abilities is promising for biomedical implants directly contacting with tumor tissues. In this study, an intelligent and biocompatible drug‐loading platform, based on a gold nanorods‐modified butyrate‐inserted NiTi‐layered double hydroxides film (Au@LDH/B), is prepared on the surface of nitinol alloy. The prepared films function as drug‐loading “sponges,” which pump butyrate out under near‐infrared (NIR) irradiation and resorb drugs in water when the NIR laser is shut off. The stimuli‐responsive release of butyrate is verified to be related with the NIR‐triggered crystal phase transformation of Au@LDH/B. In vitro and in vivo studies reveal that the prepared films possess excellent biosafety and high efficiency in synergistic thermochemo tumor therapy, showing a promising application in the construction of localized stimuli‐responsive drug‐delivery systems. PMID:29721424

Distinct regions of the Phytophthora essential effector Avh238 determine its function in cell death activation and plant immunity suppression.

PubMed

Yang, Bo; Wang, Qunqing; Jing, Maofeng; Guo, Baodian; Wu, Jiawei; Wang, Haonan; Wang, Yang; Lin, Long; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Wang, Yuanchao

2017-04-01

Phytophthora pathogens secrete effectors to manipulate host innate immunity, thus facilitating infection. Among the RXLR effectors highly induced during Phytophthora sojae infection, Avh238 not only contributes to pathogen virulence but also triggers plant cell death. However, the detailed molecular basis of Avh238 functions remains largely unknown. We mapped the regions responsible for Avh238 functions in pathogen virulence and plant cell death induction using a strategy that combines investigation of natural variation and large-scale mutagenesis assays. The correlation between cellular localization and Avh238 functions was also evaluated. We found that the 79 th residue (histidine or leucine) of Avh238 determined its cell death-inducing activity, and that the 53 amino acids in its C-terminal region are responsible for promoting Phytophthora infection. Transient expression of Avh238 in Nicotiana benthamiana revealed that nuclear localization is essential for triggering cell death, while Avh238-mediated suppression of INF1-triggered cell death requires cytoplasmic localization. Our results demonstrate that a representative example of an essential Phytophthora RXLR effector can evolve to escape recognition by the host by mutating one nucleotide site, and can also retain plant immunosuppressive activity to enhance pathogen virulence in planta. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Localized Iron Supply Triggers Lateral Root Elongation in Arabidopsis by Altering the AUX1-Mediated Auxin Distribution[C][W][OA

PubMed Central

Giehl, Ricardo F.H.; Lima, Joni E.; von Wirén, Nicolaus

2012-01-01

Root system architecture depends on nutrient availability, which shapes primary and lateral root development in a nutrient-specific manner. To better understand how nutrient signals are integrated into root developmental programs, we investigated the morphological response of Arabidopsis thaliana roots to iron (Fe). Relative to a homogeneous supply, localized Fe supply in horizontally separated agar plates doubled lateral root length without having a differential effect on lateral root number. In the Fe uptake-defective mutant iron-regulated transporter1 (irt1), lateral root development was severely repressed, but a requirement for IRT1 could be circumvented by Fe application to shoots, indicating that symplastic Fe triggered the local elongation of lateral roots. The Fe-stimulated emergence of lateral root primordia and root cell elongation depended on the rootward auxin stream and was accompanied by a higher activity of the auxin reporter DR5-β-glucuronidase in lateral root apices. A crucial role of the auxin transporter AUXIN RESISTANT1 (AUX1) in Fe-triggered lateral root elongation was indicated by Fe-responsive AUX1 promoter activities in lateral root apices and by the failure of the aux1-T mutant to elongate lateral roots into Fe-enriched agar patches. We conclude that a local symplastic Fe gradient in lateral roots upregulates AUX1 to accumulate auxin in lateral root apices as a prerequisite for lateral root elongation. PMID:22234997

Shallow microearthquakes near Chongqing, China triggered by the Rayleigh waves of the 2015 M7.8 Gorkha, Nepal earthquake

NASA Astrophysics Data System (ADS)

Han, Libo; Peng, Zhigang; Johnson, Christopher W.; Pollitz, Fred F.; Li, Lu; Wang, Baoshan; Wu, Jing; Li, Qiang; Wei, Hongmei

2017-12-01

We present a case of remotely triggered seismicity in Southwest China by the 2015/04/25 M7.8 Gorkha, Nepal earthquake. A local magnitude ML3.8 event occurred near the Qijiang district south of Chongqing city approximately 12 min after the Gorkha mainshock. Within 30 km of this ML3.8 event there are 62 earthquakes since 2009 and only 7 ML > 3 events, which corresponds to a likelihood of 0.3% for a ML > 3 on any given day by a random chance. This observation motivates us to investigate the relationship between the ML3.8 event and the Gorkha mainshock. The ML3.8 event was listed in the China Earthquake National Center (CENC) catalog and occurred at shallow depth (∼3 km). By examining high-frequency waveforms, we identify a smaller local event (∼ML 2.5) ∼ 15 s before the ML3.8 event. Both events occurred during the first two cycles of the Rayleigh waves from the Gorkha mainshock. We perform seismic event detection based on envelope function and waveform matching by using the two events as templates. Both analyses found a statistically significant rate change during the mainshock, suggesting that they were indeed dynamically triggered by the Rayleigh waves. Both events occurred during the peak normal and dilatational stress changes (∼10-30 kPa), consistent with observations of dynamic triggering in other geothermal/volcanic regions. Although other recent events (i.e., the 2011 M9.1 Tohoku-Oki earthquake) produced similar peak ground velocities, the 2015 Gorkha mainshock was the only event that produced clear dynamic triggering in this region. The triggering site is close to hydraulic fracturing wells that began production in 2013-2014. Hence we suspect that fluid injections may increase the region's susceptibility to remote dynamic triggering.

Shallow microearthquakes near Chongqing, China triggered by the Rayleigh waves of the 2015 M7.8 Gorkha, Nepal earthquake

USGS Publications Warehouse

Han, Libo; Peng, Zhigang; Johnson, Christopher W.; Pollitz, Fred; Li, Lu; Wang, Baoshan; Wu, Jing; Li, Qiang; Wei, Hongmei

2017-01-01

We present a case of remotely triggered seismicity in Southwest China by the 2015/04/25 M7.8 Gorkha, Nepal earthquake. A local magnitude ML3.8 event occurred near the Qijiang district south of Chongqing city approximately 12 min after the Gorkha mainshock. Within 30km of this ML3.8 event there are 62 earthquakes since 2009 and only 7 ML>3events, which corresponds to a likelihood of 0.3% for a ML>3on any given day by a random chance. This observation motivates us to investigate the relationship between the ML3.8 event and the Gorkha mainshock. The ML3.8 event is listed in the China Earthquake National Center (CENC) catalog and occurred at shallow depth (∼3km). By examining high-frequency waveforms, we identify a smaller local event (∼ML2.5) ∼15s before the ML3.8 event. Both events occurred during the first two cycles of the Rayleigh waves from the Gorkha mainshock. We perform seismic event detection based on envelope function and waveform matching by using the two events as templates. Both analyses found a statistically significant rate change during the mainshock, suggesting that they were indeed dynamically triggered by the Rayleigh waves. Both events occurred during the peak normal and dilatational stress changes (∼10–30 kPa), consistent with observations of dynamic triggering in other geothermal/volcanic regions. Although other recent events (i.e., the 2011 M9.1 Tohoku-Oki earthquake) produced similar peak ground velocities, the 2015 Gorkha mainshock was the only event that produced clear dynamic triggering in this region. The triggering site is close to hydraulic fracturing wells that began production in 2013–2014. Hence we suspect that fluid injections may increase the region’s susceptibility to remote dynamic triggering.

Nuclear accumulation of the Arabidopsis immune receptor RPS4 is necessary for triggering EDS1-dependent defense.

PubMed

Wirthmueller, Lennart; Zhang, Yan; Jones, Jonathan D G; Parker, Jane E

2007-12-04

Recognition of specific pathogen molecules inside the cell by nucleotide-binding domain and leucine-rich repeat (NB-LRR) receptors constitutes an important layer of innate immunity in plants. Receptor activation triggers host cellular reprogramming involving transcriptional potentiation of basal defenses and localized programmed cell death. The sites and modes of action of NB-LRR receptors are, however, poorly understood. Arabidopsis Toll/Interleukin-1 (TIR) type NB-LRR receptor RPS4 recognizes the bacterial type III effector AvrRps4. We show that epitope-tagged RPS4 expressed under its native regulatory sequences distributes between endomembranes and nuclei in healthy and AvrRps4-triggered tissues. RPS4 accumulation in the nucleus, mediated by a bipartite nuclear localization sequence (NLS) at its C terminus, is necessary for triggering immunity through authentic activation by AvrRps4 in Arabidopsis or as an effector-independent "deregulated" receptor in tobacco. A strikingly conserved feature of TIR-NB-LRR receptors is their recruitment of the nucleocytoplasmic basal-defense regulator EDS1 in resistance to diverse pathogens. We find that EDS1 is an indispensable component of RPS4 signaling and that it functions downstream of RPS4 activation but upstream of RPS4-mediated transcriptional reprogramming in the nucleus.

Sediment gravity flows triggered by remotely generated earthquake waves

NASA Astrophysics Data System (ADS)

Johnson, H. Paul; Gomberg, Joan S.; Hautala, Susan L.; Salmi, Marie S.

2017-06-01

Recent great earthquakes and tsunamis around the world have heightened awareness of the inevitability of similar events occurring within the Cascadia Subduction Zone of the Pacific Northwest. We analyzed seafloor temperature, pressure, and seismic signals, and video stills of sediment-enveloped instruments recorded during the 2011-2015 Cascadia Initiative experiment, and seafloor morphology. Our results led us to suggest that thick accretionary prism sediments amplified and extended seismic wave durations from the 11 April 2012 Mw8.6 Indian Ocean earthquake, located more than 13,500 km away. These waves triggered a sequence of small slope failures on the Cascadia margin that led to sediment gravity flows culminating in turbidity currents. Previous studies have related the triggering of sediment-laden gravity flows and turbidite deposition to local earthquakes, but this is the first study in which the originating seismic event is extremely distant (> 10,000 km). The possibility of remotely triggered slope failures that generate sediment-laden gravity flows should be considered in inferences of recurrence intervals of past great Cascadia earthquakes from turbidite sequences. Future similar studies may provide new understanding of submarine slope failures and turbidity currents and the hazards they pose to seafloor infrastructure and tsunami generation in regions both with and without local earthquakes.

Sediment gravity flows triggered by remotely generated earthquake waves

USGS Publications Warehouse

Johnson, H. Paul; Gomberg, Joan S.; Hautala, Susan; Salmi, Marie

2017-01-01

Recent great earthquakes and tsunamis around the world have heightened awareness of the inevitability of similar events occurring within the Cascadia Subduction Zone of the Pacific Northwest. We analyzed seafloor temperature, pressure, and seismic signals, and video stills of sediment-enveloped instruments recorded during the 2011–2015 Cascadia Initiative experiment, and seafloor morphology. Our results led us to suggest that thick accretionary prism sediments amplified and extended seismic wave durations from the 11 April 2012 Mw8.6 Indian Ocean earthquake, located more than 13,500 km away. These waves triggered a sequence of small slope failures on the Cascadia margin that led to sediment gravity flows culminating in turbidity currents. Previous studies have related the triggering of sediment-laden gravity flows and turbidite deposition to local earthquakes, but this is the first study in which the originating seismic event is extremely distant (> 10,000 km). The possibility of remotely triggered slope failures that generate sediment-laden gravity flows should be considered in inferences of recurrence intervals of past great Cascadia earthquakes from turbidite sequences. Future similar studies may provide new understanding of submarine slope failures and turbidity currents and the hazards they pose to seafloor infrastructure and tsunami generation in regions both with and without local earthquakes.

Where do we stand after twenty years of dynamic triggering studies? (Invited)

NASA Astrophysics Data System (ADS)

Prejean, S. G.; Hill, D. P.

2013-12-01

In the past two decades, remote dynamic triggering of earthquakes by other earthquakes has been explored in a variety of physical environments with a wide array of observation and modeling techniques. These studies have significantly refined our understanding of the state of the crust and the physical conditions controlling earthquake nucleation. Despite an ever growing database of dynamic triggering observations, significant uncertainties remain and vigorous debate in almost all aspects of the science continues. For example, although dynamic earthquake triggering can occur with peak dynamic stresses as small as 1 kPa, triggering thresholds and their dependence on local stress state, hydrological environment, and frictional properties of faults are not well understood. Some studies find a simple threshold based on the peak amplitude of shaking while others find dependencies on frequency, recharge time, and other parameters. Considerable debate remains over the range of physical processes responsible for dynamic triggering, and the wide variation in dynamic triggering responses and time scales suggests triggering by multiple physical processes. Although Coulomb shear failure with various friction laws can often explain dynamic triggering, particularly instantaneous triggering, delayed dynamic triggering may be dependent on fluid transport and other slowly evolving aseismic processes. Although our understanding of the global distribution of dynamic triggering has improved, it is far from complete due to spatially uneven monitoring. A major challenge involves establishing statistical significance of potentially triggered earthquakes, particularly if they are isolated events or time-delayed with respect to triggering stresses. Here we highlight these challenges and opportunities with existing data. We focus on environmental dependence of dynamic triggering by large remote earthquakes particularly in volcanic and geothermal systems, as these systems often have high rates of background seismicity. In many volcanic and geothermal systems, such as the Geysers in Northern California, dynamic triggering of micro-earthquakes is frequent and predictable. In contrast, most active and even erupting volcanoes in Alaska (with the exception of the Katmai Volcanic Cluster) do not experience dynamic triggering. We explore why.

Energy Deposition in the Body from External Sources to Chemically Trigger Cellular Responses in Desired Localized Regions

NASA Astrophysics Data System (ADS)

Ibsen, Stuart Duncan

One of the major challenges of modern chemotherapy is to deliver a therapeutic dose of active drug to the tumor tissue without causing systemic exposure. The realization of this goal could considerably reduce the negative side effects experienced by patients. The work conducted in this thesis looks at two different approaches to trigger drug activation with the use of external energy sources. This avoids the challenges of relying solely on biochemical and environmental differences as triggers. The two triggers used were low intensity focused ultrasound and 365 nm light delivered with a custom designed needle UV LED fiber optic system. Both can be localized within the body to spatially highlight just the tumor tissue creating a stark differentiation between it and the healthy tissue. The 365nm light based delivery scheme developed here was the first demonstration of a photoactivatable doxorubicin (DOX) prodrug called DOX-PCB. DOX-PCB was shown to be 200 times less toxic than DOX and could be activated to a fully therapeutic form upon exposure to 365nm light. The pharmacokinetics showed a circulation half life comparable to that of DOX and stability against in vivo metabolic degradation. The 365 nm light was shown to adequately irradiate a centimeter of tumor tissue and cause localized activation. In vivo tumors exposed to the light had significantly higher doses of DOX than unexposed control tumors in the same individual. The second delivery scheme made use of focused ultrasound to activate echogenic drug delivery vehicles. These vehicles were the first demonstration of encapsulating microbubbles within liposomes. Specially designed optical equipment documented that the microbubble was ultrasound responsive. The microbubble was shown to violently cavitate and rupture the outer liposome membrane releasing the payload contents. The three dimensional localization of activation was demonstrated in tissue phantoms. The strengths of these two delivery schemes could complement each other when used together. The delivery vehicle could achieve high doses of DOX-PCB within the tumor while the low toxicity prevents harm to the liver and spleen. The 365 nm light could then activate just the DOX-PCB found within the tumor itself causing localized cell death.

Photon-triggered nanowire transistors

NASA Astrophysics Data System (ADS)

Kim, Jungkil; Lee, Hoo-Cheol; Kim, Kyoung-Ho; Hwang, Min-Soo; Park, Jin-Sung; Lee, Jung Min; So, Jae-Pil; Choi, Jae-Hyuck; Kwon, Soon-Hong; Barrelet, Carl J.; Park, Hong-Gyu

2017-10-01

Photon-triggered electronic circuits have been a long-standing goal of photonics. Recent demonstrations include either all-optical transistors in which photons control other photons or phototransistors with the gate response tuned or enhanced by photons. However, only a few studies report on devices in which electronic currents are optically switched and amplified without an electrical gate. Here we show photon-triggered nanowire (NW) transistors, photon-triggered NW logic gates and a single NW photodetection system. NWs are synthesized with long crystalline silicon (CSi) segments connected by short porous silicon (PSi) segments. In a fabricated device, the electrical contacts on both ends of the NW are connected to a single PSi segment in the middle. Exposing the PSi segment to light triggers a current in the NW with a high on/off ratio of >8 × 106. A device that contains two PSi segments along the NW can be triggered using two independent optical input signals. Using localized pump lasers, we demonstrate photon-triggered logic gates including AND, OR and NAND gates. A photon-triggered NW transistor of diameter 25 nm with a single 100 nm PSi segment requires less than 300 pW of power. Furthermore, we take advantage of the high photosensitivity and fabricate a submicrometre-resolution photodetection system. Photon-triggered transistors offer a new venue towards multifunctional device applications such as programmable logic elements and ultrasensitive photodetectors.

Photon-triggered nanowire transistors.

PubMed

Kim, Jungkil; Lee, Hoo-Cheol; Kim, Kyoung-Ho; Hwang, Min-Soo; Park, Jin-Sung; Lee, Jung Min; So, Jae-Pil; Choi, Jae-Hyuck; Kwon, Soon-Hong; Barrelet, Carl J; Park, Hong-Gyu

2017-10-01

Photon-triggered electronic circuits have been a long-standing goal of photonics. Recent demonstrations include either all-optical transistors in which photons control other photons or phototransistors with the gate response tuned or enhanced by photons. However, only a few studies report on devices in which electronic currents are optically switched and amplified without an electrical gate. Here we show photon-triggered nanowire (NW) transistors, photon-triggered NW logic gates and a single NW photodetection system. NWs are synthesized with long crystalline silicon (CSi) segments connected by short porous silicon (PSi) segments. In a fabricated device, the electrical contacts on both ends of the NW are connected to a single PSi segment in the middle. Exposing the PSi segment to light triggers a current in the NW with a high on/off ratio of >8 × 10 6 . A device that contains two PSi segments along the NW can be triggered using two independent optical input signals. Using localized pump lasers, we demonstrate photon-triggered logic gates including AND, OR and NAND gates. A photon-triggered NW transistor of diameter 25 nm with a single 100 nm PSi segment requires less than 300 pW of power. Furthermore, we take advantage of the high photosensitivity and fabricate a submicrometre-resolution photodetection system. Photon-triggered transistors offer a new venue towards multifunctional device applications such as programmable logic elements and ultrasensitive photodetectors.

Observation of the L-H confinement bifurcation triggered by a turbulence-driven shear flow in a tokamak plasma.

PubMed

Yan, Z; McKee, G R; Fonck, R; Gohil, P; Groebner, R J; Osborne, T H

2014-03-28

Comprehensive 2D turbulence and eddy flow velocity measurements on DIII-D demonstrate a rapidly increasing turbulence-driven shear flow that develops ∼100  μs prior to the low-confinement (L mode) to high-confinement (H mode) transition and appears to trigger it. These changes are localized to a narrow layer 1-2 cm inside the magnetic boundary. Increasing heating power increases the Reynolds stress, the energy transfer from turbulence to the poloidal flow, and the edge flow shearing rate that then exceeds the decorrelation rate, suppressing turbulence and triggering the transition.

Seismic link at plate boundary

NASA Astrophysics Data System (ADS)

Ramdani, Faical; Kettani, Omar; Tadili, Benaissa

2015-06-01

Seismic triggering at plate boundaries has a very complex nature that includes seismic events at varying distances. The spatial orientation of triggering cannot be reduced to sequences from the main shocks. Seismic waves propagate at all times in all directions, particularly in highly active zones. No direct evidence can be obtained regarding which earthquakes trigger the shocks. The first approach is to determine the potential linked zones where triggering may occur. The second step is to determine the causality between the events and their triggered shocks. The spatial orientation of the links between events is established from pre-ordered networks and the adapted dependence of the spatio-temporal occurrence of earthquakes. Based on a coefficient of synchronous seismic activity to grid couples, we derive a network link by each threshold. The links of high thresholds are tested using the coherence of time series to determine the causality and related orientation. The resulting link orientations at the plate boundary conditions indicate that causal triggering seems to be localized along a major fault, as a stress transfer between two major faults, and parallel to the geothermal area extension.

Systolic blood pressure reactivity during submaximal exercise and acute psychological stress in youth

USDA-ARS?s Scientific Manuscript database

Background: Studies in youth show an association between systolic blood-pressure (SBP) reactivity to acute psychological stress and carotid artery intima-media thickness (CIMT). However, it has not yet been determined whether SBP reactivity during submaximal exercise is also associated with CIMT i...

Cardiovascular risk factors and carotid intima media thickness in young adults born small for gestational age after cessation of growth hormone treatment: a 5-year longitudinal study.

PubMed

van der Steen, Manouk; Kerkhof, Gerthe F; Smeets, Carolina C J; Hokken-Koelega, Anita C S

2017-12-01

Growth hormone treatment reduces blood pressure and lipid concentrations. We assessed long-term changes in blood pressure, lipid concentrations, and carotid intima media thickness over a 5-year period after cessation of growth hormone treatment in adults born small for gestational age. We did a longitudinal observational study at a medical centre in the Netherlands between April 1, 2004, and April 1, 2016. We included adults born small for gestational age who were treated with growth hormone (1 mg/m 2 per day); treatment started during childhood until adult height. Participants were evaluated at cessation of treatment, and 6 months, 2 years, and 5 years later. We compared cardiovascular risk factors with untreated controls from the PROGRAM study. We included 199 participants born small for gestational age and treated with growth hormone along with 285 controls: 51 untreated short adults born small for gestational age, 92 untreated adults born small for gestational age with spontaneous catch-up growth, and 142 adults born appropriate for gestational age. In the 6 months after treatment cessation, systolic blood pressure increased temporarily from 113·00 mm Hg (95% CI 111·18-114·82) to 116·92 mm Hg (115·07 to 118·77; p<0·001) and diastolic blood pressure increased temporarily from 62·19 mm Hg (60·99-63·38) to 66·51 mm Hg (65·14-67·89; p<0·001). At 5 years after treatment cessation, mean systolic blood pressure was 109·2 mm Hg (105·5-113·0) and mean diastolic blood pressure was 63·4 mm Hg (60·9-65·9), similar to the values at cessation. Lipid concentrations were non-significantly higher 5 years after treatment cessation (p values 0·09-0·21) than at treatment cessation. Cessation of growth hormone had no effect on carotid intima media thickness. At 5 years after cessation, total cholesterol was lower in adults treated with growth hormone (mean 4·21 mmol/L, 95% CI 4·04-4·38) than in untreated short adults born small for gestational age (4·66 mmol/L, 4·42-4·92; p=0·0030), as was mean LDL cholesterol (2·28 mmol/L, 2·14-2·43 vs 2·85 mmol/L, 2·62-3·10; p<0·0001); blood pressure and carotid intima media thickness did not differ between these two groups (p values >0·12). At 5 years after cessation, systolic blood pressure, diastolic blood pressure, lipid concentrations, and carotid intima media thickness of adults treated with growth hormone were not different to those in adults born small for gestational age who had spontaneous catch-up growth or adults born appropriate for gestational age. Long-term growth hormone treatment in children born small for gestational age has no unfavourable effects on cardiovascular health in early adulthood and improves lipid profiles. Novo Nordisk (Netherlands). Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and validation of the Overlap Muon Track Finder for the CMS experiment

NASA Astrophysics Data System (ADS)

Dobosz, J.; Mietki, P.; Zawistowski, K.; Żarnecki, G.

2016-09-01

Present article is a description of the authors contribution in upgrade and analysis of performance of the Level-1 Muon Trigger of the CMS experiment. The authors are students of University of Warsaw and Gdansk University of Technology. They are collaborating with the CMS Warsaw Group. This article summarises students' work presented during the Students session during the Workshop XXXVIII-th IEEE-SPIE Joint Symposium Wilga 2016. In the first section the CMS experiment is briefly described and the importance of the trigger system is explained. There is also shown basic difference between old muon trigger strategy and the upgraded one. The second section is devoted to Overlap Muon Track Finder (OMTF). This is one of the crucial components of the Level-1 Muon Trigger. The algorithm of OMTF is described. In the third section there is discussed one of the event selection aspects - cut on the muon transverse momentum pT . Sometimes physical muon with pT bigger than a certain threshold is unnecessarily cut and physical muon with lower pT survives. To improve pT selection modified algorithm was proposed and its performance was studied. One of the features of the OMTF is that one physical muon often results in several muon candidates. The Ghost-Buster algorithm is designed to eliminate surplus candidates. In the fourth section this algorithm and its performance on different data samples are discussed. In the fifth section Local Data Acquisition System (Local DAQ) is briefly described. It supports initial system commissioning. The test done with OMTF Local DAQ are described. In the sixth section there is described development of web application used for the control and monitoring of CMS electronics. The application provides access to graphical user interface for manual control and the connection to the CMS hierarchical Run Control.

Cytoplasmic and nuclear localizations are important for the hypersensitive response conferred by maize autoactive Rp1-D21 protein

USDA-ARS?s Scientific Manuscript database

Disease resistance (R-) genes have been isolated from many plant species. Most encode nucleotide binding leucine-rich-repeat (NLR) proteins that trigger a rapid localized programmed cell death termed the hypersensitive response (HR) upon pathogen recognition. Despite their structural similarities, d...

Unique concurrent observations of whistler mode hiss, chorus, and triggered emissions

NASA Astrophysics Data System (ADS)

Hosseini, Poorya; Gołkowski, Mark; Turner, Drew L.

2017-06-01

We present a unique 2 h ground-based observation of concurrent magnetospheric hiss, chorus, VLF triggered emissions as well as ELF/VLF signals generated locally by the High Frequency Active Auroral Research Program (HAARP) facility. Eccentricity of observed wave polarization is used as a criteria to identify magnetospheric emissions and estimate their ionospheric exit points. The observations of hiss and chorus in the unique background of coherent HAARP ELF/VLF waves and triggered emissions allow for more accurate characterization of hiss and chorus properties than in typical ground-based observations. Eccentricity and azimuth results suggest a moving ionospheric exit point associated with a single ducted path at L 5. The emissions exhibit dynamics in time suggesting an evolution of a magnetospheric source from hiss generation to chorus generation or a moving plasmapause location. We introduce a frequency band-limited autocorrelation method to quantify the relative coherency of the emissions. A range of coherency was observed from high order of coherency in local HAARP transmissions and their echoes to lower coherency in natural chorus and hiss emissions.

Reducing Environmental Allergic Triggers: Policy Issues.

PubMed

Abramson, Stuart L

The implementation of policies to reduce environmental allergic triggers can be an important adjunct to optimal patient care for allergic rhinitis and allergic asthma. Policies at the local level in schools and other public as well as private buildings can make an impact on disease morbidity. Occupational exposures for allergens have not yet been met with the same rigorous policy standards applied for exposures to toxicants by Occupational Safety and Health Administration. Further benefit may be obtained through policies by local, county, state, and national governments, and possibly through international cooperative agreements. The reduction of allergenic exposures can and should be affected by policies with strong scientific, evidence-based derivation. However, a judicious application of the precautionary principle may be needed in circumstances where the health effect of inaction could lead to more serious threats to vulnerable populations with allergic disease. This commentary covers the scientific basis, current implementation, knowledge gaps, and pro/con views on policy issues in reducing environmental allergic triggers. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Sudden cardiac death: the pro-arrhythmic interaction of an acute loading with an underlying substrate.

PubMed

Sutherland, George R

2017-10-21

Sudden cardiac death (SCD) is a complex phenomenon, occurring either in apparently normal individuals or in those where there is a recognized underlying cardiac abnormality. In both groups, the lethal arrhythmia has frequently been related to the physiologic trigger of either exercise or stress. Prior research into SCD has focused mainly on a combination of identifying either vulnerable myocardial substrates; pharmacological approaches to altering electrical activation/repolarisation in substrates; or the suppression of induced lethal arrhythmias with implantable defibrillators. However, it has been suggested that in a significant number of cases, the interaction of a transient induced trigger with a pre-existing electrical or mechanical substrate is the basis for the induction of the sustained lethal arrhythmia. In this manuscript we will discuss the precise mechanisms whereby one of such potential physiologic trigger: an acute change in systolic blood pressure, can induce a sequence of alterations in global and local cardiac mechanics which in turn result in regional left ventricular post-systolic deformation which, mediated (through stretch-induced changes in local mechano-electrical coupling) provokes local electrical after-depolarisations which can spill over into complex runs of premature ventricular beats. These local acute pressure/stretch induced runs of ventricular ectopy originate in either basal or apical normal myocardium and, in combination with a co-existing distal pro-arrhymic substrate, can interact to induce a lethal arrhythmia. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

Near-infrared remotely triggered drug-release strategies for cancer treatment

NASA Astrophysics Data System (ADS)

Goodman, Amanda M.; Neumann, Oara; Nørregaard, Kamilla; Henderson, Luke; Choi, Mi-Ran; Clare, Susan E.; Halas, Naomi J.

2017-11-01

Remotely controlled, localized drug delivery is highly desirable for potentially minimizing the systemic toxicity induced by the administration of typically hydrophobic chemotherapy drugs by conventional means. Nanoparticle-based drug delivery systems provide a highly promising approach for localized drug delivery, and are an emerging field of interest in cancer treatment. Here, we demonstrate near-IR light-triggered release of two drug molecules from both DNA-based and protein-based hosts that have been conjugated to near-infrared-absorbing Au nanoshells (SiO2 core, Au shell), each forming a light-responsive drug delivery complex. We show that, depending upon the drug molecule, the type of host molecule, and the laser illumination method (continuous wave or pulsed laser), in vitro light-triggered release can be achieved with both types of nanoparticle-based complexes. Two breast cancer drugs, docetaxel and HER2-targeted lapatinib, were delivered to MDA-MB-231 and SKBR3 (overexpressing HER2) breast cancer cells and compared with release in noncancerous RAW 264.7 macrophage cells. Continuous wave laser-induced release of docetaxel from a nanoshell-based DNA host complex showed increased cell death, which also coincided with nonspecific cell death from photothermal heating. Using a femtosecond pulsed laser, lapatinib release from a nanoshell-based human serum albumin protein host complex resulted in increased cancerous cell death while noncancerous control cells were unaffected. Both methods provide spatially and temporally localized drug-release strategies that can facilitate high local concentrations of chemotherapy drugs deliverable at a specific treatment site over a specific time window, with the potential for greatly minimized side effects.

Triggering of frequent turbidity currents in Monterey Canyon and the role of antecedent conditioning

NASA Astrophysics Data System (ADS)

Clare, M. A.; Rosenberger, K. J.; Talling, P.; Barry, J.; Maier, K. L.; Parsons, D. R.; Simmons, S.; Gales, J. A.; Gwiazda, R.; McGann, M.; Paull, C. K.

2017-12-01

Turbidity currents pose a hazard to seafloor infrastructure, deliver organic carbon and nutrients to deep-sea communities, and form economically important deposits. Thus, determining the tempo of turbidity current activity and whether different triggers result in different flow modes is important. Identification of specific triggers is challenging, however, because most studies of turbidity currents are based on their deposits. New direct monitoring of flows and environmental conditions provides the necessary temporal constraints to identify triggering mechanisms. The Coordinated Canyon Experiment (CCE) in Monterey Canyon, offshore California is the most ambitious attempt yet to measure turbidity flows and their triggers. The CCE provides precise constraint on flow timing, initiation, and potential triggers based on measurements at 7 different instrumented moorings and 2 metocean buoys. Fifteen turbidity flows were measured in 18 months; with recorded velocities >8 m/s and run-outs of up to 50 km. Presence of live estuarine foraminifera within moored sediment traps suggests that that flows originated in water depths of <10 m, but it is unclear specifically how these flows were triggered. Turbidity currents are thought to be triggered by processes including earthquakes, river floods and storm waves. Here we analyse seismicity, local river discharge, internal tides, wave height, direction and period data. We identify no clear control of any of these individual variables on flow timing. None of the recorded earthquakes (

[Myofascial pain syndrome--frequent occurrence and often misdiagnosed].

PubMed

Pongratz, D E; Späth, M

1998-09-30

Myofascial pain syndrome (MPS) is a very common localized--sometimes also polytopic--painful musculoskeletal condition associated with trigger points, for which, however, diagnostic criteria established in well-designed studies are still lacking. These two facts form the basis for differentiating between MPS and the fibromyalgia syndrome. The difference between trigger points (MPS) and tender points (fibromyalgia) is of central importance--not merely in a linguistic sense. A knowledge of the signs and symptoms typically associated with a trigger point often obviates the need for time-consuming and expensive technical diagnostic measures. The assumption that many cases of unspecific complaints affecting the musculoskeletal system may be ascribed to MPS makes clear the scope for the saving of costs.

Identification of a nuclear-localized nuclease from wheat cells undergoing programmed cell death that is able to trigger DNA fragmentation and apoptotic morphology on nuclei from human cells

PubMed Central

Domínguez, Fernando; Cejudo, Francisco J.

2006-01-01

PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently or from a common ancestor in plants and animals. In the present study we describe a cell-free system, using wheat grain nucellar cells undergoing PCD, to analyse nucleus dismantling, the final stage of PCD. We have identified a Ca2+/Mg2+ nuclease and a serine protease localized to the nucleus of dying nucellar cells. Nuclear extracts from nucellar cells undergoing PCD triggered DNA fragmentation and other apoptotic morphology in nuclei from different plant tissues. Inhibition of the serine protease did not affect DNA laddering. Furthermore, we show that the nuclear extracts from plant cells triggered DNA fragmentation and apoptotic morphology in nuclei from human cells. The inhibition of the nucleolytic activity with Zn2+ or EDTA blocked the morphological changes of the nucleus. Moreover, nuclear extracts from apoptotic human cells triggered DNA fragmentation and apoptotic morphology in nuclei from plant cells. These results show that degradation of the nucleus is morphologically and biochemically similar in plant and animal cells. The implication of this finding on the origin of PCD in plants and animals is discussed. PMID:16613587

The outdoor air quality flag program in central California: a school-based educational intervention to potentially help reduce children's exposure to environmental asthma triggers.

PubMed

Shendell, Derek G; Rawling, Mary-Michal; Foster, Christine; Bohlke, Alicia; Edwards, Bobbie; Rico, Susie A; Felix, Justina; Eaton, Sandra; Moen, Stephanie; Roberts, Eric M; Love, Mary Beth

2007-10-01

This paper describes a novel school-based, visual environmental public health educational intervention intended to help reduce the exposure of children-and adults-to outdoor air pollution, including known environmental asthma triggers like ozone and particles. The overarching goal was to enhance the learning, recreational, and work environments of students and staff. The specific purpose of the Asthma-Friendly Outdoor (Ambient) Air Quality Flag Program was to establish an education and communication tool for Central California communities that would accomplish two things: (1) Establish permanent local policy change to existing operating procedures in school districts and schools to help reduce the exposure of students, teachers, staff, and nearby communities to outdoor environmental asthma triggers and (2) provide education on air quality and potential health effects of exposure to air pollutants. Data on the program from its initial years are presented. To date, the following important lessons have been learned: (1) Science-based, simple, visual, low-cost school-based educational interventions to help reduce human exposure to outdoor environmental asthma triggers (i.e., ozone, particles, and pollens) can work in socioeconomically and ethnically diverse urban and rural or agricultural communities, and (2) local health and environmental justice groups such as asthma coalitions can successfully lead school-based environmental interventions to help improve children's quality of life.

How to Choose? Using the Delphi Method to Develop Consensus Triggers and Indicators for Disaster Response.

PubMed

Lis, Rebecca; Sakata, Vicki; Lien, Onora

2017-08-01

To identify key decisions along the continuum of care (conventional, contingency, and crisis) and the critical triggers and data elements used to inform those decisions concerning public health and health care response during an emergency. A classic Delphi method, a consensus-building survey technique, was used with clinicians around Washington State to identify regional triggers and indicators. Additionally, using a modified Delphi method, we combined a workshop and single-round survey with panelists from public health (state and local) and health care coalitions to identify consensus state-level triggers and indicators. In the clinical survey, 122 of 223 proposed triggers or indicators (43.7%) reached consensus and were deemed important in regional decision-making during a disaster. In the state-level survey, 110 of 140 proposed triggers or indicators (78.6%) reached consensus and were deemed important in state-level decision-making during a disaster. The identification of consensus triggers and indicators for health care emergency response is crucial in supporting a comprehensive health care situational awareness process. This can inform the creation of standardized questions to ask health care, public health, and other partners to support decision-making during a response. (Disaster Med Public Health Preparedness. 2017;11:467-472).

The trigger system of the JEM-EUSO Project

NASA Astrophysics Data System (ADS)

Bertaina, M.; Ebisuzaki, T.; Hamada, T.; Ikeda, H.; Kawasai, Y.; Sawabe, T.; Takahashi, Y.; JEM-EUSO Collaboration

The trigger system of JEM-EUSO should face different major challenging points: a) cope with the limited down-link transmission rate from the ISS to Earth, by operating a severe on-board and on-time data reduction; b) use very fast, low power consuming and radiation hard electronics; c) have a high signal-over-noise performance and flexibility in order to lower as much as possible the energy threshold of the detector, adjust the system to a variable nightglow background, and trigger on different categories of events (images insisting on the same pixels or crossing huge portions of the entire focal surface). Based on the above stringent requirements, the main ingredients for the trigger logic are: the Gate Time Unit (GTU); the minimum number Nthresh of photo-electrons piling up in a GTU in a pixel to be fired; the persistency level Npers, in which fired pixels are over threshold; the localization and correlation in space and time of the fired pixels, that distinguish a real EAS from an accidental background enhancement. The core of the trigger logic is the Track Trigger Algorithm that has been specifically developed for this purpose. Its characteristics, preliminary performance and its possible implementation on FPGA or DSP will be discussed together with a general overview of the architecture of the triggering system of JEM-EUSO.

Local auxin production underlies a spatially restricted neighbor-detection response in Arabidopsis

PubMed Central

Michaud, Olivier

2017-01-01

Competition for light triggers numerous developmental adaptations known as the “shade-avoidance syndrome” (SAS). Important molecular events underlying specific SAS responses have been identified. However, in natural environments light is often heterogeneous, and it is currently unknown how shading affecting part of a plant leads to local responses. To study this question, we analyzed upwards leaf movement (hyponasty), a rapid adaptation to neighbor proximity, in Arabidopsis. We show that manipulation of the light environment at the leaf tip triggers a hyponastic response that is restricted to the treated leaf. This response is mediated by auxin synthesized in the blade and transported to the petiole. Our results suggest that a strong auxin response in the vasculature of the treated leaf and auxin signaling in the epidermis mediate leaf elevation. Moreover, the analysis of an auxin-signaling mutant reveals signaling bifurcation in the control of petiole elongation versus hyponasty. Our work identifies a mechanism for a local shade response that may pertain to other plant adaptations to heterogeneous environments. PMID:28652343

In vivo covalent cross-linking of photon-converted rare-earth nanostructures for tumour localization and theranostics

NASA Astrophysics Data System (ADS)

Ai, Xiangzhao; Ho, Chris Jun Hui; Aw, Junxin; Attia, Amalina Binte Ebrahim; Mu, Jing; Wang, Yu; Wang, Xiaoyong; Wang, Yong; Liu, Xiaogang; Chen, Huabing; Gao, Mingyuan; Chen, Xiaoyuan; Yeow, Edwin K. L.; Liu, Gang; Olivo, Malini; Xing, Bengang

2016-01-01

The development of precision nanomedicines to direct nanostructure-based reagents into tumour-targeted areas remains a critical challenge in clinics. Chemical reaction-mediated localization in response to tumour environmental perturbations offers promising opportunities for rational design of effective nano-theranostics. Here, we present a unique microenvironment-sensitive strategy for localization of peptide-premodified upconversion nanocrystals (UCNs) within tumour areas. Upon tumour-specific cathepsin protease reactions, the cleavage of peptides induces covalent cross-linking between the exposed cysteine and 2-cyanobenzothiazole on neighbouring particles, thus triggering the accumulation of UCNs into tumour site. Such enzyme-triggered cross-linking of UCNs leads to enhanced upconversion emission upon 808 nm laser irradiation, and in turn amplifies the singlet oxygen generation from the photosensitizers attached on UCNs. Importantly, this design enables remarkable tumour inhibition through either intratumoral UCNs injection or intravenous injection of nanoparticles modified with the targeting ligand. Our strategy may provide a multimodality solution for effective molecular sensing and site-specific tumour treatment.

Resilient filtering for time-varying stochastic coupling networks under the event-triggering scheduling

NASA Astrophysics Data System (ADS)

Wang, Fan; Liang, Jinling; Dobaie, Abdullah M.

2018-07-01

The resilient filtering problem is considered for a class of time-varying networks with stochastic coupling strengths. An event-triggered strategy is adopted to save the network resources by scheduling the signal transmission from the sensors to the filters based on certain prescribed rules. Moreover, the filter parameters to be designed are subject to gain perturbations. The primary aim of the addressed problem is to determine a resilient filter that ensures an acceptable filtering performance for the considered network with event-triggering scheduling. To handle such an issue, an upper bound on the estimation error variance is established for each node according to the stochastic analysis. Subsequently, the resilient filter is designed by locally minimizing the derived upper bound at each iteration. Moreover, rigorous analysis shows the monotonicity of the minimal upper bound regarding the triggering threshold. Finally, a simulation example is presented to show effectiveness of the established filter scheme.

Microearthquake streaks and seismicity triggered by slow earthquakes on the mobile south flank of Kilauea Volcano, Hawai'i

USGS Publications Warehouse

Wolfe, C.J.; Brooks, B.A.; Foster, J.H.; Okubo, P.G.

2007-01-01

We perform waveform cross correlation and high precision relocation of both background seismicity and seismicity triggered by periodic slow earthquakes at Kilauea Volcano's mobile south flank. We demonstrate that the triggered seismicity dominantly occurs on several preexisting fault zones at the Hilina region. Regardless of the velocity model employed, the relocated earthquake epicenters and triggered seismicity localize onto distinct fault zones that form streaks aligned with the slow earthquake surface displacements determined from GPS. Due to the unknown effects of velocity heterogeneity and nonideal station coverage, our relocation analyses cannot distinguish whether some of these fault zones occur within the volcanic crust at shallow depths or whether all occur on the decollement between the volcano and preexisting oceanic crust at depths of ???8 km. Nonetheless, these Hilina fault zones consistently respond to stress perturbations from nearby slow earthquakes. Copyright 2007 by the American Geophysical Union.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguiar, Ana C.; Chao, Kevin; Beroza, Gregory C.

In this paper, we compare low-frequency earthquakes (LFEs) from triggered and ambient tremor under the southern Central Range, Taiwan. We apply the PageRank algorithm used by Aguiar and Beroza (2014) that exploits the repetitive nature of the LFEs to find repeating LFEs in both ambient and triggered tremor. We use these repeaters to create LFE templates and find that the templates created from both tremor types are very similar. To test their similarity, we use both interchangeably and find that most of both the ambient and triggered tremor match the LFE templates created from either data set, suggesting that LFEsmore » for both events have a common origin. Finally, we locate the LFEs by using local earthquake P wave and S wave information and find that LFEs from triggered and ambient tremor locate to between 20 and 35 km on what we interpret as the deep extension of the Chaochou-Lishan Fault.« less

Pastoral community organization, livelihoods and biodiversity conservation in Mongolia's Southern Gobi Region

Treesearch

Sabine M. Schmidt

2006-01-01

In this paper I describe processes and impacts of collective action by mobile pastoralist communities, and of external support strategies to strengthen local institutions and cooperation in Mongolia’s southern Gobi. The need for pastoral mobility triggered the processes leading to community organization, and the emergence, or re-emergence, of local informal...

The LUX experiment - trigger and data acquisition systems

NASA Astrophysics Data System (ADS)

Druszkiewicz, Eryk

2013-04-01

The Large Underground Xenon (LUX) detector is a two-phase xenon time projection chamber designed to detect interactions of dark matter particles with the xenon nuclei. Signals from the detector PMTs are processed by custom-built analog electronics which provide properly shaped signals for the trigger and data acquisition (DAQ) systems. During calibrations, both systems must be able to handle high rates and have large dynamic ranges; during dark matter searches, maximum sensitivity requires low thresholds. The trigger system uses eight-channel 64-MHz digitizers (DDC-8) connected to a Trigger Builder (TB). The FPGA cores on the digitizers perform real-time pulse identification (discriminating between S1 and S2-like signals) and event localization. The TB uses hit patterns, hit maps, and maximum response detection to make trigger decisions, which are reached within few microseconds after the occurrence of an event of interest. The DAQ system is comprised of commercial digitizers with customized firmware. Its real-time baseline suppression allows for a maximum event acquisition rate in excess of 1.5 kHz, which results in virtually no deadtime. The performance of the trigger and DAQ systems during the commissioning runs of LUX will be discussed.

Influence of obesity and metabolic disease on carotid atherosclerosis in patients with coronary artery disease (CordioPrev study)

USDA-ARS?s Scientific Manuscript database

Background: Recent data suggest that the presence of associated metabolic abnormalities may be important modifiers of the association of obesity with a poorer prognosis in coronary heart disease. We determined the influence of isolated overweight and obesity on carotid intima media thickness (IMT-CC...

Insulin resistance and carotid intima-media thickness mediate the association between resting-state heart rate variability and executive function: A path modelling study.

PubMed

Kemp, Andrew H; López, Santiago Rodríguez; Passos, Valeria M A; Bittencourt, Marcio S; Dantas, Eduardo M; Mill, José G; Ribeiro, Antonio L P; Thayer, Julian F; Bensenor, Isabela M; Lotufo, Paulo A

2016-05-01

Research has linked high-frequency heart rate variability (HF-HRV) to cognitive function. The present study adopts a modern path modelling approach to understand potential causal pathways that may underpin this relationship. Here we examine the association between resting-state HF-HRV and executive function in a large sample of civil servants from Brazil (N=8114) recruited for the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). HF-HRV was calculated from 10-min resting-state electrocardiograms. Executive function was assessed using the trail-making test (version B). Insulin resistance (a marker of type 2 diabetes mellitus) and carotid intima-media thickness (subclinical atherosclerosis) mediated the relationship between HRV and executive function in seriatim. A limitation of the present study is its cross-sectional design; therefore, conclusions must be confirmed in longitudinal study. Nevertheless, findings support that possibility that HRV provides a 'spark' that initiates a cascade of adverse downstream effects that subsequently leads to cognitive impairment. Copyright © 2016 Elsevier B.V. All rights reserved.

Association between diabetic retinopathy and subclinical atherosclerosis in China: Results from a community-based study.

PubMed

Liu, Yu; Teng, Xiangyu; Zhang, Wei; Zhang, Ruifeng; Liu, Wei

2015-09-01

To evaluate the association of diabetic retinopathy with subclinical atherosclerosis in middle-aged and elderly Chinese with type 2 diabetes. A cross-sectional community-based study was performed among 1607 patients aged 40 years or older in Shanghai. Non-mydriatic digital fundus photography examination was used in diabetic retinopathy detection. Presence of elevated carotid intima-media thickness or carotid plaque was defined as subclinical atherosclerosis. The prevalence of diabetic retinopathy was 15.1% in total patients. Patients with diabetic retinopathy were more likely to have elevated carotid intima-media thickness, carotid plaque and subclinical atherosclerosis than those without diabetic retinopathy (37.9% vs 30.7%, 57.6% vs 49.6% and 64.6% vs 57.1%, respectively). The presence of diabetic retinopathy was significantly associated with increased odds of subclinical atherosclerosis (odds ratio = 1.93, 95% confidence interval = 1.03-3.60) after full adjustments. The presence of diabetic retinopathy was significantly associated with subclinical atherosclerosis in middle-aged and elderly patients with type 2 diabetics in China. © The Author(s) 2015.

Effect of Acarbose on Long-Term Prognosis in Acute Coronary Syndromes Patients with Newly Diagnosed Impaired Glucose Tolerance.

PubMed

Yun, Peng; Du, Ai-ming; Chen, Xue-jun; Liu, Jing-cheng; Xiao, Hu

2016-01-01

To investigate the effect of acarbose therapy on the long-term prognosis of patients with acute coronary syndromes (ACS) complicating newly diagnosed impaired glucose tolerance (IGT). 135 patients hospitalized for ACS who had been newly diagnosed with IGT were randomly assigned to acarbose group (150 mg/day, n = 67) or control group (no acarbose, n = 68). All cases in each group were given the same elementary treatment. Mean follow-up was 2.3 years. The incidence of major adverse cardiovascular event (MACE) and carotid intima-middle thickness (CIMT) were statistically analyzed. During the mean follow-up of 2.3 years, the risk of recurrent MACE in acarbose group was decreased significantly compared with that in control group (26.67% versus 46.88%, P < 0.05); at the same time, thickening of the CIMT was significantly slower than the control group ((1.28 ± 0.42) mm versus (1.51 ± 0.64) mm, P < 0.05). Acarbose can effectively reduce the risk of MACE in ACS patients with newly diagnosed IGT, simultaneously retarding the progression of carotid intima-media thickness.

Histology of Tissue Adherent to OptEase Inferior Vena Cava Filters Regarding Indwelling Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rimon, Uri, E-mail: rimonu@sheba.health.gov.il; Volkov, Alexander; Garniek, Alexander

The purpose of this paper is to report on the histology of tissues found on retrieved filters with regard to indwelling time. Between February 2006 and January 2007, 28 Optease inferior vena cava filters (Cordis Europa, Roden, The Netherlands) were retrieved from 27 patients. Twenty-two filters were inserted prophylactically for trauma patients and six for patients with venous thromboembolism. Cavography was performed both before and after filter removal to evaluate the presence of thrombi or wall damage. Filters were retrieved with the snare and sheath method. All material adherents to the filters were examined histologically.The mean indwelling time of themore » filters was 24.9 days (range, 6-69 days). Red tissue fragments were seen on all the filters, consistent microscopically with clots and fibrin. On five filters (18%; mean indwelling time, 45.4 days) white tissue consistent with vascular intima was found. All postprocedure cavographies were normal. We conclude that most material adherent to the retrieved filters is thrombi, while vascular intima can be found in the minority of filters with a longer indwelling time.« less

Among overweight middle-aged men, first-borns have lower insulin sensitivity than second-borns

PubMed Central

Albert, Benjamin B.; de Bock, Martin; Derraik, José G. B.; Brennan, Christine M.; Biggs, Janene B.; Hofman, Paul L.; Cutfield, Wayne S.

2014-01-01

We aimed to assess whether birth order affects metabolism and body composition in overweight middle-aged men. We studied 50 men aged 45.6 ± 5.5 years, who were overweight (BMI 27.5 ± 1.7 kg/m2) but otherwise healthy in Auckland, New Zealand. These included 26 first-borns and 24 second-borns. Insulin sensitivity was assessed by the Matsuda method from an oral glucose tolerance test. Other assessments included DXA-derived body composition, lipid profiles, 24-hour ambulatory blood pressure, and carotid intima-media thickness. First-born men were 6.9 kg heavier (p = 0.013) and had greater BMI (29.1 vs 27.5 kg/m2; p = 0.004) than second-borns. Insulin sensitivity in first-born men was 33% lower than in second-borns (4.38 vs 6.51; p = 0.014), despite adjustment for fat mass. There were no significant differences in ambulatory blood pressure, lipid profile or carotid intima-media thickness between first- and second-borns. Thus, first-born adults may be at a greater risk of metabolic and cardiovascular diseases. PMID:24503677

Overview of the SVOM Gamma-Ray Burst mission under development with a focus on its Trigger system

NASA Astrophysics Data System (ADS)

Schanne, Stephane

2017-08-01

The SVOM mission (Space-based Variable Objects Monitor) is a Chinese-French satellite mission under development, devoted to collecting a complete sample of Gamma-Ray Bursts (GRBs) observed at multi-wavelengths with a high fraction of redshift determinations. In January 2017 the mission entered Phase C, starting officially construction, and the launch is foreseen in 2021. The SVOM satellite is equipped with 4 instruments, 2 of which cover the prompt GRB phase. The ECLAIRs coded-mask imager surveys a 2-sr large portion of the sky in the 4-150 keV energy range, well suited for the detection of X-ray rich and highly redshifted GRBs. The ECLAIRs trigger system continuously searches for GRBs using two algorithms, a count-rate trigger for short time scales and an image trigger for long time scales. In case of a localized new GRB candidate or a bright outburst of a known source, it promptly requests a satellite slew and sends an alert to ground. The onboard GRM (Gamma-Ray Monitor) extends the prompt energy coverage up to 5 MeV. After slew, 2 more onboard instruments study the GRB afterglow and refine the GRB localization: the MXT (Multi-pore optics X-ray Telescope) and the VT (Visible Telescope). Two types of ground telescopes are dedicated to SVOM. The GFTs (Ground Follow-up Telescopes) repoint autonomously to GRB alerts, refine their localization and provide photometric redshift. The SVOM observing strategy with roughly antisolar pointing combined with Galactic plane avoidance, ensures that most GRBs are quickly visible by the GFTs and large spectroscopic telescopes. The GWAC (Ground Wide Angle Camera) will observe the sky simultaneously with ECLAIRs to detect prompt optical GRB emissions. Today part of the GWAC is already operational. The SVOM GRB program is complemented by pre-planned target observations and ground-commanded targets of opportunity, e.g. to search for electromagnetic counterparts of gravity-wave events. On behalf of the SVOM and ECLAIRs teams, this paper presents an overview of SVOM with a focus on its GRB trigger system.

Seismicity Increase in North China After the 2008 Mw7.9 Wenchuan Earthquake.

NASA Astrophysics Data System (ADS)

Goldhagen, G.; Li, C.; Peng, Z.; Wu, J.; Zhao, L.

2016-12-01

A large mainshock is capable of setting off an increase in seismicity in areas thousands of kilometers away. This phenomenon, known as remote triggering, is more likely to occur along active fault lines, aftershock zones, or regions with anthropogenic activities (e.g., mining, reservoirs, and fluid injections). By studying these susceptible areas, we can gain a better understanding of subsurface stress conditions, and long-range earthquake interactions. In this study we conduct a systematic search for remotely triggered seismicity in North China along two linear dense arrays (net code 1A and Z8) deployed by Chinese Academy of Sciences (CAS) following the 2008 Mw7.9 Wenchuan earthquake. A 5 Hz high pass filter is applied to the broadband seismogram recorded at the 1A array, which is more than 2,000 km away from the mainshock, in order to manually pick local events with double peaks. These local events have higher frequencies than earthquakes in the aftershock zone of the Wenchuan earthquake. An STA/LTA method is then employed as a way to automatically detect microseismicity in a section of the array that showed preliminary evidence of remote triggering. We find a clear increase of small earthquakes, right after the surface waves of the Wenchuan mainshock. These events, were recorded at stations close to the north section of the Tanlu fault and aftershock zones of the 1975, Ms7.3 Haicheng earthquake. This result suggests that remote triggering is more likely near active fault zones or other specific regions, as previous studies have proposed. Future work includes applying a waveform matching method to both arrays and automatically detecting micro-earthquakes missed on the catalog, and using them to better confirm the existence (or lack of) remote triggering following the Wenchuan mainshock. Our finding helps to better classify conditions that lead to the occurrence of remotely triggered earthquakes at intraplate regions.

Reduction of ELM Intensity on DIII-D by On-demand Triggering With High Frequency Pellet Injection and Implications for ITER

NASA Astrophysics Data System (ADS)

Baylor, L. R.

2012-10-01

Deuterium pellet injection was used on the DIII-D tokamak to successfully demonstrate for the first time the on-demand triggering of ELMs at a 10x higher rate, and with much smaller intensity, than natural edge localized modes (ELMs). The triggering of small ELMs by high frequency pellet injection has been proposed as a method to prevent large ELMs that can erode the ITER plasma facing components [1]. The demonstration was made by injecting slow (<200 m/s) 1.3 mm diameter deuterium pellets at 60 Hz from the low field side in an ITER similar plasma with 5 Hz natural ELM frequency. The input power was only slightly above the H-mode threshold. Similar non-pellet discharges had ELM energy losses up to 55 kJ (˜8% of total stored energy), while the case with pellets demonstrated ELMs with an average energy loss less than 3 kJ (<1% of the total). Total divertor ELM heat flux was reduced by more than a factor of 10. Central accumulation of Ni was significantly reduced in the pellet triggered ELM case. No significant increase in density or decrease in energy confinement was observed. Stability analysis of these discharges shows that the pedestal parameters are approaching the peeling unstable region just before a natural ELM crash. In the rapid pellet small ELM case, the pedestal conditions are well within the stable region with a narrower pedestal width observed. This narrower width is consistent with a picture in which the pellets are triggering the ELMs before the width expands to the critical ELM width. Nonlinear MHD simulations of the pellet ELM triggering show destabilization of ballooning modes by a local pressure perturbation. The implications of these results for pellet ELM pacing in ITER will be discussed. 6pt [1] P.T. Lang et al., Nucl. Fusion 44, 665 (2004).

Source mechanism inversion and ground motion modeling of induced earthquakes in Kuwait - A Bayesian approach

NASA Astrophysics Data System (ADS)

Gu, C.; Toksoz, M. N.; Marzouk, Y.; Al-Enezi, A.; Al-Jeri, F.; Buyukozturk, O.

2016-12-01

The increasing seismic activity in the regions of oil/gas fields due to fluid injection/extraction and hydraulic fracturing has drawn new attention in both academia and industry. Source mechanism and triggering stress of these induced earthquakes are of great importance for understanding the physics of the seismic processes in reservoirs, and predicting ground motion in the vicinity of oil/gas fields. The induced seismicity data in our study are from Kuwait National Seismic Network (KNSN). Historically, Kuwait has low local seismicity; however, in recent years the KNSN has monitored more and more local earthquakes. Since 1997, the KNSN has recorded more than 1000 earthquakes (Mw < 5). In 2015, two local earthquakes - Mw4.5 in 03/21/2015 and Mw4.1 in 08/18/2015 - have been recorded by both the Incorporated Research Institutions for Seismology (IRIS) and KNSN, and widely felt by people in Kuwait. These earthquakes happen repeatedly in the same locations close to the oil/gas fields in Kuwait (see the uploaded image). The earthquakes are generally small (Mw < 5) and are shallow with focal depths of about 2 to 4 km. Such events are very common in oil/gas reservoirs all over the world, including North America, Europe, and the Middle East. We determined the location and source mechanism of these local earthquakes, with the uncertainties, using a Bayesian inversion method. The triggering stress of these earthquakes was calculated based on the source mechanisms results. In addition, we modeled the ground motion in Kuwait due to these local earthquakes. Our results show that most likely these local earthquakes occurred on pre-existing faults and were triggered by oil field activities. These events are generally smaller than Mw 5; however, these events, occurring in the reservoirs, are very shallow with focal depths less than about 4 km. As a result, in Kuwait, where oil fields are close to populated areas, these induced earthquakes could produce ground accelerations high enough to cause damage to local structures without using seismic design criteria.

Common Carotid Artery Diameter and Risk of Cardiovascular Events and Mortality: Pooled Analyses of Four Cohort Studies.

PubMed

Sedaghat, Sanaz; van Sloten, Thomas T; Laurent, Stéphane; London, Gérard M; Pannier, Bruno; Kavousi, Maryam; Mattace-Raso, Francesco; Franco, Oscar H; Boutouyrie, Pierre; Ikram, M Arfan; Stehouwer, Coen D A

2018-05-21

Carotid arterial diameter enlargement is a manifestation of arterial remodeling and may be a risk factor for cardiovascular disease (CVD). We evaluated the association between carotid artery diameter and risk of stroke, coronary heart disease, CVD, and all-cause mortality and explored whether the associations could be explained by processes involved in arterial remodeling, that is, blood pressure-related media thickening, arterial stiffness, arterial wall stress, and atherosclerosis. We included 4887 participants (mean age 67±9 years; 54% women) from 4 cohort studies: Rotterdam Study, NEPHROTEST, Hoorn Study, and a study by Blacher et al. Common carotid artery properties were measured using echotracking. Incident cases were recorded based on medical records. We used Cox proportional hazard models adjusting for cardiovascular risk factors and estimates of processes underlying arterial remodeling. During follow-up (mean, 11 years), 379 (8%) individuals had a stroke, 516 had a (11%) coronary heart disease, 807 had a (17%) CVD, and 1486 (30%) had died. After adjustment for cardiovascular risk factors, individuals in the highest tertile of carotid diameter (diameter >8 mm) compared with those in the lowest tertile (diameter <7 mm) had a higher incidence of stroke (hazard ratio, 1.5; 95% confidence interval, 1.1-2.0). From all estimates of processes underlying arterial remodeling, adjustment for carotid intima-media thickness attenuated this association (hazard ratio after adjustment for intima-media thickness, 1.2; 95% confidence interval, 0.9-1.6). Larger carotid diameter was associated with risk of CVD and mortality but not clearly with coronary heart disease risk. We showed that a larger carotid diameter is associated with incident stroke, CVD, and mortality. Carotid intima-media thickness, a measure of blood pressure-related media thickening, partially explained the association with stroke incidence. © 2018 American Heart Association, Inc.

ASSESSMENT OF DIASTOLIC DYSFUNCTION, ARTERIAL STIFFNESS, AND CAROTID INTIMA-MEDIA THICKNESS IN PATIENTS WITH ACROMEGALY.

PubMed

Cansu, Güven Barış; Yılmaz, Nusret; Yanıkoğlu, Atakan; Özdem, Sebahat; Yıldırım, Aytül Belgi; Süleymanlar, Gültekin; Altunbaş, Hasan Ali

2017-05-01

Early diagnosis and treatment of cardiovascular diseases, the most frequent cause of morbidity and mortality in acromegaly, may be an efficient approach to extending the lifespan of affected patients. Therefore, it is crucial to determine any cardiovascular diseases in the subclinical period. The study objectives were to determine markers of subclinical atherosclerosis and asses heart structure and function. This was a cross-sectional, single-center study of 53 patients with acromegaly and 22 age- and sex-matched healthy individuals. Carotid intima-media thickness (CIMT), pulse-wave velocity (PWV), and echocardiographic data were compared between these groups. CIMT and PWV were higher in the acromegaly group than in the healthy group (P = .008 and P = .002, respectively). Echocardiography showed that left ventricular diastolic dysfunction was present in 11.3% of patients. Left ventricular mass index and left atrial volume index were higher in the patients (P = .016 and P<.001, respectively). No differences in the CIMT, PWV, or echocardiographic measurements were identified between the patients with biochemically controlled and uncontrolled acromegaly and the control group. Our results showed that subclinical atherosclerosis (i.e., CIMT and PWV markers) and heart structure and function were worse in patients with acromegaly than in healthy individuals. Because there were no differences in these parameters between patients with controlled and uncontrolled acromegaly, our results suggest that the structural and functional changes do not reverse with biochemical control. AA = active acromegaly BSA = body surface area CA = biochemically controlled acromegaly CH = concentric hypertrophy CIMT = carotid intima-media thickness DBP = diastolic blood pressure DM = diabetes mellitus ECHO = echocardiography EDV = enddiastolic volume EF = ejection fraction ESV = endsystolic volume GH = growth hormone HC = healthy control HL = hyperlipidemia HT = hypertension IGF-1 = insulin-like growth factor 1 LA = left atrial LAV = left atrial volume LAVI = left atrial volume index LV = left ventricular LVDD = left ventricular diastolic dysfunction LVEF = left ventricular ejection fraction LVH = left ventricular hypertrophy LVMI = left ventricular mass index PWV = pulse-wave velocity RWT = relative wall thickness.

Study of the intima-media thickening in carotid arteries of healthy elderly with high blood pressure and elderly with high blood pressure and dyslipidemia

PubMed Central

de Freitas, Elizabete Viana; Brandão, Andréa Araújo; Pozzan, Roberto; Magalhães, Maria Eliane; Castier, Márcia; Brandão, Airton Pires

2008-01-01

Objective The objective of this study was to assess the mean intima-media thickening of carotid arteries of elderly subjects, and its relationship with age, anthropometric measurements, high systolic blood pressure and dyslipidemia. Methods In this investigation, 129 subjects were enrolled between 1995 and 1998, age ranging from 29 to 94 years. They were assigned to one of 4 groups, including 2 control groups (group I, of healthy younger subjects; group II of healthy elderly subjects). Groups III and IV included those who presented with isolated systolic hypertension (ISH), and ISH and dyslipidemia, respectively. All subjects were submitted to a medical interview, lab tests with measurement of cholesterol levels, electrocardiogram, and carotid ultrasound. The ultrasound included measurement of the intima-media thickening (IMT) of the carotid arteries, the right carotid artery (RCA) and left carotid artery (LCA), and assessment of the presence of plaques. Blood fat and glucose were measured by a standard method. The results were compared among the groups through statistical tests. The tests employed were: Chi-Square, Pearson’s and Likelihood Ratio, Student’s t, Mann-Whitney; ANOVA followed by Tukey’s test, Kruskal-Wallis nonparametric test, and test for multiple comparisons and Odds Ratio determination (OR). Results In this investigation, a positive association was observed between aging and IMT. In relation to systolic hypertension, a significant association was observed with IMT (IMT-RCA p = 0.0034; IMT-LCA p = 0.0196; IMT-RLCA p = 0.0299), and with the presence of plaques (PlaqueR p = 0.0110; PlaqueL p = 0.0294; PlaqueRL p = 0.0040). Conclusion This investigation evidenced the important role of aging in IMT, and of systolic hypertension in the IMT and presence of plaque. However, further studies are needed for a better understanding of the actual role of risk factors in aging. PMID:18982922

Femoral Artery Atherosclerosis Is Associated With Physical Function Across the Spectrum of the Ankle-Brachial Index: The San Diego Population Study.

PubMed

Wassel, Christina L; Ellis, Alicia M; Suder, Natalie C; Barinas-Mitchell, Emma; Rifkin, Dena E; Forbang, Nketi I; Denenberg, Julie O; Marasco, Antoinette M; McQuaide, Belinda J; Jenny, Nancy S; Allison, Matthew A; Ix, Joachim H; Criqui, Michael H

2017-07-20

The ankle-brachial index (ABI) is inadequate to detect early-stage atherosclerotic disease, when interventions to prevent functional decline may be the most effective. We determined associations of femoral artery atherosclerosis with physical functioning, across the spectrum of the ABI, and within the normal ABI range. In 2007-2011, 1103 multiethnic men and women participated in the San Diego Population Study, and completed all components of the summary performance score. Using Doppler ultrasound, superficial and common femoral intima media thickness and plaques were ascertained. Logistic regression was used to assess associations of femoral atherosclerosis with the summary performance score and its individual components. Models were adjusted for demographics, lifestyle factors, comorbidities, lipids, and kidney function. In adjusted models, among participants with a normal-range ABI (1.00-1.30), the highest tertile of superficial intima media thickness was associated with lower odds of a perfect summary performance score of 12 (odds ratio=0.56 [0.36, 0.87], P =0.009), and lower odds of a 4-m walk score of 4 (0.34 [0.16, 0.73], P =0.006) and chair rise score of 4 (0.56 [0.34, 0.94], P =0.03). Plaque presence (0.53 [0.29, 0.99], P =0.04) and greater total plaque burden (0.61 [0.43, 0.87], P =0.006) were associated with worse 4-m walk performance in the normal-range ABI group. Higher superficial intima media thickness was associated with lower summary performance score in all individuals ( P =0.02). Findings suggest that use of femoral artery atherosclerosis measures may be effective in individuals with a normal-range ABI, especially, for example, those with diabetes mellitus or a family history of peripheral artery disease, when detection can lead to earlier intervention to prevent functional declines and improve quality of life. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Associations between homocysteine metabolism related SNPs and carotid intima-media thickness: a Chinese sib pair study.

PubMed

Sun, Kexin; Song, Jing; Liu, Kuo; Fang, Kai; Wang, Ling; Wang, Xueyin; Li, Jing; Tang, Xun; Wu, Yiqun; Qin, Xueying; Wu, Tao; Gao, Pei; Chen, Dafang; Hu, Yonghua

2017-04-01

Carotid intima-media thickness (CIMT) is a good surrogate for atherosclerosis. Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. We aim to investigate the relationships between homocysteine (Hcy) related biochemical indexes and CIMT, the associations between Hcy related SNPs and CIMT, as well as the potential gene-gene interactions. The present study recruited full siblings (186 eligible families with 424 individuals) with no history of cardiovascular events from a rural area of Beijing. We examined CIMT, intima-media thickness for common carotid artery (CCA-IMT) and carotid bifurcation, tested plasma levels for Hcy, vitamin B6 (VB6), vitamin B12 (VB12) and folic acid (FA), and genotyped 9 SNPs on MTHFR, MTR, MTRR, BHMT, SHMT1, CBS genes. Associations between SNPs and biochemical indexes and CIMT indexes were analyzed using family-based association test analysis. We used multi-level mixed-effects regression model to verify SNP-CIMT associations and to explore the potential gene-gene interactions. VB6, VB12 and FA were negatively correlated with CIMT indexes (p < 0.05). rs2851391 T allele was associated with decreased plasma VB12 levels (p = 0.036). In FABT, CBS rs2851391 was significantly associated with CCA-IMT (p = 0.021) and CIMT (p = 0.019). In multi-level mixed-effects regression model, CBS rs2851391 was positively significantly associated with CCA-IMT (Coef = 0.032, se = 0.009, raw p < 0.001) after Bonferoni correction (corrected α = 0.0056). Gene-gene interactions were found between CBS rs2851391 and BHMT rs10037045 for CCA-IMT (p = 0.011), as well as between CBS rs2851391 and MTR rs1805087 for CCA-IMT (p = 0.007) and CIMT (p = 0.022). Significant associations are found between Hcy metabolism related genetic polymorphisms, biochemical indexes and CIMT indexes. There are complex interactions between genetic polymorphisms for CCA-IMT and CIMT.

Physical exercise, fitness and dietary pattern and their relationship with circadian blood pressure pattern, augmentation index and endothelial dysfunction biological markers: EVIDENT study protocol

PubMed Central

2010-01-01

Background Healthy lifestyles may help to delay arterial aging. The purpose of this study is to analyze the relationship of physical activity and dietary pattern to the circadian pattern of blood pressure, central and peripheral blood pressure, pulse wave velocity, carotid intima-media thickness and biological markers of endothelial dysfunction in active and sedentary individuals without arteriosclerotic disease. Methods/Design Design: A cross-sectional multicenter study with six research groups. Subjects: From subjects of the PEPAF project cohort, in which 1,163 who were sedentary became active, 1,942 were sedentary and 2,346 were active. By stratified random sampling, 1,500 subjects will be included, 250 in each group. Primary measurements: We will evaluate height, weight, abdominal circumference, clinical and ambulatory blood pressure with the Radial Pulse Wave Acquisition Device (BPro), central blood pressure and augmentation index with Pulse Wave Application Software (A-Pulse) and SphymgoCor System Px (Pulse Wave Analysis), pulse wave velocity (PWV) with SphymgoCor System Px (Pulse Wave Velocity), nutritional pattern with a food intake frequency questionnaire, physical activity with the 7-day PAR questionnaire and accelerometer (Actigraph GT3X), physical fitness with the cycle ergometer (PWC-170), carotid intima-media thickness by ultrasound (Micromax), and endothelial dysfunction biological markers (endoglin and osteoprotegerin). Discussion Determining that sustained physical activity and the change from sedentary to active as well as a healthy diet improve circadian pattern, arterial elasticity and carotid intima-media thickness may help to propose lifestyle intervention programs. These interventions could improve the cardiovascular risk profile in some parameters not routinely assessed with traditional risk scales. From the results of this study, interventional approaches could be obtained to delay vascular aging that combine physical exercise and diet. Trial Registration Clinical Trials.gov Identifier: NCT01083082 PMID:20459634

Comparison of Carotid-Femoral and Brachial-Ankle Pulse-Wave Velocity in Association With Target Organ Damage in the Community-Dwelling Elderly Chinese: The Northern Shanghai Study.

PubMed

Lu, Yuyan; Zhu, Mengyun; Bai, Bin; Chi, Chen; Yu, Shikai; Teliewubai, Jiadela; Xu, Henry; Wang, Kai; Xiong, Jing; Zhou, Yiwu; Ji, Hongwei; Fan, Ximin; Yu, Xuejing; Li, Jue; Blacher, Jacques; Zhang, Yi; Xu, Yawei

2017-02-20

Carotid-femoral pulse-wave velocity (cf-PWV) and brachial-ankle PWV (ba-PWV) are the 2 most frequently applied PWV measurements. However, little is known about the comparison of hypertensive target organ damage (TOD) with cf-PWV and ba-PWV. A total of 1599 community-dwelling elderly subjects (age >65 years) in northern Shanghai were recruited from June 2014 to August 2015. Both cf-PWV and ba-PWV were measured using SphygmoCor and VP1000 systems, respectively. Within the framework of comprehensive cardiovascular examinations, risk factors were assessed, and asymptomatic TOD, including left ventricular mass index, peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity (E/Ea), carotid intima-media thickness, arterial plaque, creatinine clearance rate, and urinary albumin-creatinine ratio were all evaluated. Both PWVs were significantly associated with male sex, age, waist/hip circumference, fasting plasma glucose, and systolic blood pressure, and ba-PWV was also significantly related to body mass index. Both PWVs were significantly correlated with most TOD. When cf-PWV and ba-PWV were both or separately put into the stepwise linear regression model together with cardiovascular risk factors and treatment, only cf-PWV, but not ba-PWV, was significantly associated with carotid intima-media thickness and creatinine clearance rate ( P <0.05). When cf-PWV and ba-PWV were both or separately put into the same full-mode model after adjustment for confounders, only cf-PWV, but not ba-PWV, showed significant association with carotid intima-media thickness and creatinine clearance rate ( P <0.05). Similar results were observed in logistic regression analysis. Taken together, in the community-dwelling elderly Chinese, cf-PWV seems to be more closely associated with hypertensive TOD, especially vascular and renal TOD, as compared with ba-PWV. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02368938. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

The relation of blood pressure and carotid intima-media thickness with the glutathione cycle in a young bi-ethnic population: the African-PREDICT study.

PubMed

Myburgh, Caitlynd; Huisman, Hugo W; Mels, Catharina M C

2018-04-01

Oxidative stress has been implicated in the development of hypertension, arterial stiffness and atherosclerosis. Optimal functioning of the enzymatic antioxidant system is central to prevent increased oxidative stress and its consequences. We aimed to investigate the relationships of ambulatory blood pressure and carotid intima-media thickness with enzyme activities of the glutathione cycle in 396 young, black and white South Africans of the African-PREDICT study. Ambulatory blood pressure and carotid intima-media thickness were measured and glutathione peroxidase and glutathione reductase activities were analyzed. Black participants had higher reactive oxygen species (men: p = 0.019; women: borderline p = 0.064) and total glutathione (both p < 0.001), but lower glutathione peroxidase activity and total antioxidant status (all p < 0.001). In black men, ambulatory pulse pressure was negatively associated with glutathione peroxidase activity (R 2  = 0.19; β = -0.25; p = 0.06). Black and white women displayed positive associations of ambulatory systolic blood pressure (black: R 2  = 0.25; β = 0.21; p = 0.048; white: R 2  = 0.44; β = 0.18; p = 0.016) with glutathione reductase activity, whereas white men displayed a positive association of ambulatory pulse pressure with glutathione reductase activity (R 2  = 0.25; β = 0.29; p = 0.01). The lower glutathione peroxidase activity and total antioxidant status, the higher reactive oxygen species, as well as the negative association between ambulatory pulse pressure and glutathione peroxidase activity in the black men suggest that oxidative stress may be associated with early vascular changes in this group. In the other three groups, the positive associations of blood pressure with glutathione reductase activity suggest a possible role for adequate glutathione reductase activity in preventing or delaying the development of hypertension.

Oral contraception vs insulin sensitization for 18 months in nonobese adolescents with androgen excess: posttreatment differences in C-reactive protein, intima-media thickness, visceral adiposity, insulin sensitivity, and menstrual regularity.

PubMed

Ibáñez, Lourdes; Díaz, Marta; Sebastiani, Giorgia; Marcos, María Victoria; López-Bermejo, Abel; de Zegher, Francis

2013-05-01

An oral estro-progestagen is the standard medication given to adolescent girls with androgen excess, even when those girls are not at risk of pregnancy. The aim of this study was to compare on-treatment and post-treatment effects of intervention with an oral contraceptive vs an insulin-sensitizing treatment for androgen excess in nonobese adolescents. This was a randomized, open-label trial. Subjects were nonobese adolescent girls with hyperinsulinemic androgen excess and without risk of pregnancy (mean age, 16 years; body mass index, 23 kg/m²; n = 34). The effects of treatment with ethinylestradiol-cyproteroneacetate (EE-CA) vs a low-dose combination of pioglitazone (7.5 mg/d), flutamide (62.5 mg/d), and metformin (850 mg/d) (PioFluMet) for 18 months were studied. Posttreatment follow-up was for 6 months. Androgen excess (hirsutism and acne scores and serum testosterone), glucose-stimulated insulinemia, circulating C-reactive protein, carotid intima media thickness, body composition (absorptiometry), abdominal fat partitioning (magnetic resonance imaging), and menstrual regularity were measured. EE-CA and PioFluMet attenuated androgen excess similarly but had divergent, and even opposing, effects on other outcomes. Six months posttreatment, the PioFluMet-treated girls had a lower glucose-induced insulinemia, a lower C-reactive protein level, and a thinner intima media than the EE-CA-treated girls, and they were viscerally less adipose, had a higher lean mass, and were more likely to have regular cycles. The on-treatment and post-treatment effects of PioFluMet compared favorably with those of oral contraception in nonobese adolescents with androgen excess. The intervention whereby androgen excess is reduced in adolescence influences the post-treatment phenotype. PioFluMet-like interventions in adolescence may thus hold the potential to prevent part of the androgen-excess phenotype in adulthood, including adiposity and subfertility.

Microvascular function predicts cardiovascular events in primary prevention: long-term results from the Firefighters and Their Endothelium (FATE) study.

PubMed

Anderson, Todd J; Charbonneau, Francois; Title, Lawrence M; Buithieu, Jean; Rose, M Sarah; Conradson, Heather; Hildebrand, Kathy; Fung, Marinda; Verma, Subodh; Lonn, Eva M

2011-01-18

Biomarkers of atherosclerosis may refine clinical decision making in individuals at risk of cardiovascular disease. The purpose of the study was to determine the prognostic significance of endothelial function and other vascular markers in apparently healthy men. The cohort consisted of 1574 men (age, 49.4 years) free of vascular disease. Measurements included flow-mediated dilation and its microvascular stimulus, hyperemic velocity, carotid intima-media thickness, and C-reactive protein. Cox proportional hazard models evaluated the relationship between vascular markers, Framingham risk score, and time to a first composite cardiovascular end point of vascular death, revascularization, myocardial infarction, angina, and stroke. Subjects had low median Framingham risk score (7.9%). Cardiovascular events occurred in 71 subjects (111 events) over a mean follow-up of 7.2±1.7 years. Flow-mediated dilation was not associated with subsequent cardiovascular events (hazard ratio, 0.92; P=0.54). Both hyperemic velocity (hazard ratio, 0.70; 95% confidence interval, 0.54 to 0.90; P=0.006) and carotid intima-media thickness (hazard ratio, 1.45; confidence interval, 1.15 to 1.83; P=0.002) but not C-reactive protein (P=0.35) were related to events in a multivariable analysis that included Framingham risk score (per unit SD). Furthermore, the addition of hyperemic velocity to Framingham risk score resulted in a net clinical reclassification improvement of 28.7% (P<0.001) after 5 years of follow-up in the intermediate-risk group. Overall net reclassification improvement for hyperemic velocity was 6.9% (P=0.24). In men, hyperemic velocity, the stimulus for flow-mediated dilation, but not flow-mediated dilation itself was a significant risk marker for adverse cardiovascular outcomes. The prognostic value was additive to traditional risk factors and carotid intima-media thickness. Hyperemic velocity, a newly described marker of microvascular function, is a novel tool that may improve risk stratification of lower-risk healthy men.

GLYCINE-RICH RNA-BINDING PROTEIN1 interacts with RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 and suppresses cell death and defense responses in pepper (Capsicum annuum).

PubMed

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

Plants use a variety of innate immune regulators to trigger cell death and defense responses against pathogen attack. We identified pepper (Capsicum annuum) GLYCINE-RICH RNA-BINDING PROTEIN1 (CaGRP1) as a RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 (CaPIK1)-interacting partner, based on bimolecular fluorescence complementation and coimmunoprecipitation analyses as well as gene silencing and transient expression analysis. CaGRP1 contains an N-terminal RNA recognition motif and a glycine-rich region at the C-terminus. The CaGRP1 protein had DNA- and RNA-binding activity in vitro. CaGRP1 interacted with CaPIK1 in planta. CaGRP1 and CaGRP1-CaPIK1 complexes were localized to the nucleus in plant cells. CaPIK1 phosphorylated CaGRP1 in vitro and in planta. Transient coexpression of CaGRP1 with CaPIK1 suppressed the CaPIK1-triggered cell death response, accompanied by a reduced CaPIK1-triggered reactive oxygen species (ROS) burst. The RNA recognition motif region of CaGRP1 was responsible for the nuclear localization of CaGRP1 as well as the suppression of the CaPIK1-triggered cell death response. CaGRP1 silencing in pepper conferred enhanced resistance to Xanthomonas campestris pv vesicatoria (Xcv) infection; however, CaPIK1-silenced plants were more susceptible to Xcv. CaGRP1 interacts with CaPIK1 and negatively regulates CaPIK1-triggered cell death and defense responses by suppressing ROS accumulation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Calcareous nannoplankton and foraminiferal response to global Oligocene and Miocene climatic oscillations: a case study from the Western Carpathian segment of the Central Paratethys

NASA Astrophysics Data System (ADS)

Holcová, Katarína

2017-06-01

The reactions of foraminiferal and calcareous nannoplankton assemblages to global warming and cooling events in the time intervals of ca. 27 to 19 Ma and 13.5 to 15 Ma (Oligocene and Miocene) were studied in subtropical epicontinental seas influenced by local tectonic and palaeogeographic events (the Central Paratethys). Regardless of these local events, global climatic processes significantly influenced the palaeoenvironment within the marine basin. Warm intervals are characterized by a stable, humid climate and a high-nutrient regime, due primarily to increased continental input of phytodetritus and also locally due to seasonal upwelling. Coarse clastics deposited in a hyposaline environment characterize the marginal part of the basin. Aridification events causing decreased riverine input and consequent nutrient decreases, characterized cold intervals. Apparent seasonality, as well as catastrophic climatic events, induced stress conditions and the expansion of opportunistic taxa. Carbonate production and hypersaline facies characterize the marginal part of the basins. Hypersaline surface water triggered downwelling circulation and mixing of water masses. Decreased abundance or extinction of K-specialists during each cold interval accelerated their speciation in the subsequent warm interval. Local tectonic events led to discordances between local and global sea-level changes (tectonically triggered uplift or subsidence) or to local salt formation (in the rain shadows of newly-created mountains).

MyShake - A smartphone app to detect earthquake

NASA Astrophysics Data System (ADS)

Kong, Q.; Allen, R. M.; Schreier, L.; Kwon, Y. W.

2015-12-01

We designed an android app that harnesses the accelerometers in personal smartphones to record earthquake-shaking data for research, hazard information and warnings. The app has the function to distinguish earthquake shakings from daily human activities based on the different patterns behind the movements. It also can be triggered by the traditional earthquake early warning (EEW) system to record for a certain amount of time to collect earthquake data. When the app is triggered by the earthquake-like movements, it sends the trigger information back to our server which contains time and location of the trigger, at the same time, it stores the waveform data on local phone first, and upload to our server later. Trigger information from multiple phones will be processed in real time on the server to find the coherent signal to confirm the earthquakes. Therefore, the app provides the basis to form a smartphone seismic network that can detect earthquake and even provide warnings. A planned public roll-out of MyShake could collect millions of seismic recordings for large earthquakes in many regions around the world.

Triggered earthquakes and the 1811-1812 New Madrid, central United States, earthquake sequence

USGS Publications Warehouse

Hough, S.E.

2001-01-01

The 1811-1812 New Madrid, central United States, earthquake sequence included at least three events with magnitudes estimated at well above M 7.0. I discuss evidence that the sequence also produced at least three substantial triggered events well outside the New Madrid Seismic Zone, most likely in the vicinity of Cincinnati, Ohio. The largest of these events is estimated to have a magnitude in the low to mid M 5 range. Events of this size are large enough to cause damage, especially in regions with low levels of preparedness. Remotely triggered earthquakes have been observed in tectonically active regions in recent years, but not previously in stable continental regions. The results of this study suggest, however, that potentially damaging triggered earthquakes may be common following large mainshocks in stable continental regions. Thus, in areas of low seismic activity such as central/ eastern North America, the hazard associated with localized source zones might be more far reaching than previously recognized. The results also provide additional evidence that intraplate crust is critically stressed, such that small stress changes are especially effective at triggering earthquakes.

The development of high-voltage repetitive low-jitter corona stabilized triggered switch

NASA Astrophysics Data System (ADS)

Geng, Jiuyuan; Yang, Jianhua; Cheng, Xinbing; Yang, Xiao; Chen, Rong

2018-04-01

The high-power switch plays an important part in a pulse power system. With the trend of pulse power technology toward modularization, miniaturization, and accuracy control, higher requirements on electrical trigger and jitter of the switch have been put forward. A high-power low-jitter corona-stabilized triggered switch (CSTS) is designed in this paper. This kind of CSTS is based on corona stabilized mechanism, and it can be used as a main switch of an intense electron-beam accelerator (IEBA). Its main feature was the use of an annular trigger electrode instead of a traditional needle-like trigger electrode, taking main and side trigger rings to fix the discharging channels and using SF6/N2 gas mixture as its operation gas. In this paper, the strength of the local field enhancement was changed by a trigger electrode protrusion length Dp. The differences of self-breakdown voltage and its stability, delay time jitter, trigger requirements, and operation range of the switch were compared. Then the effect of different SF6/N2 mixture ratio on switch performance was explored. The experimental results show that when the SF6 is 15% with the pressure of 0.2 MPa, the hold-off voltage of the switch is 551 kV, the operating range is 46.4%-93.5% of the self-breakdown voltage, the jitter is 0.57 ns, and the minimum trigger voltage requirement is 55.8% of the peak. At present, the CSTS has been successfully applied to an IEBA for long time operation.

The development of high-voltage repetitive low-jitter corona stabilized triggered switch.

PubMed

Geng, Jiuyuan; Yang, Jianhua; Cheng, Xinbing; Yang, Xiao; Chen, Rong

2018-04-01

The high-power switch plays an important part in a pulse power system. With the trend of pulse power technology toward modularization, miniaturization, and accuracy control, higher requirements on electrical trigger and jitter of the switch have been put forward. A high-power low-jitter corona-stabilized triggered switch (CSTS) is designed in this paper. This kind of CSTS is based on corona stabilized mechanism, and it can be used as a main switch of an intense electron-beam accelerator (IEBA). Its main feature was the use of an annular trigger electrode instead of a traditional needle-like trigger electrode, taking main and side trigger rings to fix the discharging channels and using SF 6 /N 2 gas mixture as its operation gas. In this paper, the strength of the local field enhancement was changed by a trigger electrode protrusion length Dp. The differences of self-breakdown voltage and its stability, delay time jitter, trigger requirements, and operation range of the switch were compared. Then the effect of different SF 6 /N 2 mixture ratio on switch performance was explored. The experimental results show that when the SF 6 is 15% with the pressure of 0.2 MPa, the hold-off voltage of the switch is 551 kV, the operating range is 46.4%-93.5% of the self-breakdown voltage, the jitter is 0.57 ns, and the minimum trigger voltage requirement is 55.8% of the peak. At present, the CSTS has been successfully applied to an IEBA for long time operation.

Remotely Triggered Earthquakes Recorded by EarthScope's Transportable Array and Regional Seismic Networks: A Case Study Of Four Large Earthquakes

NASA Astrophysics Data System (ADS)

Velasco, A. A.; Cerda, I.; Linville, L.; Kilb, D. L.; Pankow, K. L.

2013-05-01

Changes in field stress required to trigger earthquakes have been classified in two basic ways: static and dynamic triggering. Static triggering occurs when an earthquake that releases accumulated strain along a fault stress loads a nearby fault. Dynamic triggering occurs when an earthquake is induced by the passing of seismic waves from a large mainshock located at least two or more fault lengths from the epicenter of the main shock. We investigate details of dynamic triggering using data collected from EarthScope's USArray and regional seismic networks located in the United States. Triggered events are identified using an optimized automated detector based on the ratio of short term to long term average (Antelope software). Following the automated processing, the flagged waveforms are individually analyzed, in both the time and frequency domains, to determine if the increased detection rates correspond to local earthquakes (i.e., potentially remotely triggered aftershocks). Here, we show results using this automated schema applied to data from four large, but characteristically different, earthquakes -- Chile (Mw 8.8 2010), Tokoku-Oki (Mw 9.0 2011), Baja California (Mw 7.2 2010) and Wells Nevada (Mw 6.0 2008). For each of our four mainshocks, the number of detections within the 10 hour time windows span a large range (1 to over 200) and statistically >20% of the waveforms show evidence of anomalous signals following the mainshock. The results will help provide for a better understanding of the physical mechanisms involved in dynamic earthquake triggering and will help identify zones in the continental U.S. that may be more susceptible to dynamic earthquake triggering.

Reliability of physical examination for diagnosis of myofascial trigger points: a systematic review of the literature.

PubMed

Lucas, Nicholas; Macaskill, Petra; Irwig, Les; Moran, Robert; Bogduk, Nikolai

2009-01-01

Trigger points are promoted as an important cause of musculoskeletal pain. There is no accepted reference standard for the diagnosis of trigger points, and data on the reliability of physical examination for trigger points are conflicting. To systematically review the literature on the reliability of physical examination for the diagnosis of trigger points. MEDLINE, EMBASE, and other sources were searched for articles reporting the reliability of physical examination for trigger points. Included studies were evaluated for their quality and applicability, and reliability estimates were extracted and reported. Nine studies were eligible for inclusion. None satisfied all quality and applicability criteria. No study specifically reported reliability for the identification of the location of active trigger points in the muscles of symptomatic participants. Reliability estimates varied widely for each diagnostic sign, for each muscle, and across each study. Reliability estimates were generally higher for subjective signs such as tenderness (kappa range, 0.22-1.0) and pain reproduction (kappa range, 0.57-1.00), and lower for objective signs such as the taut band (kappa range, -0.08-0.75) and local twitch response (kappa range, -0.05-0.57). No study to date has reported the reliability of trigger point diagnosis according to the currently proposed criteria. On the basis of the limited number of studies available, and significant problems with their design, reporting, statistical integrity, and clinical applicability, physical examination cannot currently be recommended as a reliable test for the diagnosis of trigger points. The reliability of trigger point diagnosis needs to be further investigated with studies of high quality that use current diagnostic criteria in clinically relevant patients.

Dynamic stresses, coulomb failure, and remote triggering: corrected

USGS Publications Warehouse

Hill, David P.

2012-01-01

Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes <1  MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid‐onset triggered seismicity that develop during the surface‐wave peak dynamic stressing. Evaluation of the triggering potential of surface‐wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love‐wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid‐onset dynamic triggering may not reside solely with a simple static‐threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20‐s Rayleigh‐wave stresses than thrust faults in the shallow seismogenic crust (<10  km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde‐to‐prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh‐wave dynamic stresses than compressional or transpressional regimes.

Right hemispheric dominance in gaze-triggered reflexive shift of attention in humans.

PubMed

Okada, Takashi; Sato, Wataru; Toichi, Motomi

2006-11-01

Recent findings suggest a right hemispheric dominance in gaze-triggered shifts of attention. The aim of this study was to clarify the dominant hemisphere in the gaze processing that mediates attentional shift. A target localization task, with preceding non-predicative gaze cues presented to each visual field, was undertaken by 44 healthy subjects, measuring reaction time (RT). A face identification task was also given to determine hemispheric dominance in face processing for each subject. RT differences between valid and invalid cues were larger when presented in the left rather than the right visual field. This held true regardless of individual hemispheric dominance in face processing. Together, these results indicate right hemispheric dominance in gaze-triggered reflexive shifts of attention in normal healthy subjects.

Methods for roof-top mini-arrays

NASA Astrophysics Data System (ADS)

Hazen, W. E.; Hazen, E. S.

1985-08-01

To test the idea of the Linsley effect mini array for the study of giant air showers, it is desirable to have a trigger that exploits the effect itself. In addition to the trigger, it is necessary to have a method for measuring the relative arrival times of the particle swarm selected by the trigger. Since the idea of mini arrays is likely to appeal to small research groups, it is desirable to try to design relatively simple and inexpensive methods, and methods that utilize existing detectors. Clusters of small detectors have been designed for operation in the local particle density realm where the probability of or = 2 particles per detector is small. Consequently, this method can discriminate pulses from each detector and thenceforth deal mainly with logic pulses.

Synthetic Rhamnolipid Bolaforms trigger an innate immune response in Arabidopsis thaliana.

PubMed

Luzuriaga-Loaiza, W Patricio; Schellenberger, Romain; De Gaetano, Yannick; Obounou Akong, Firmin; Villaume, Sandra; Crouzet, Jérôme; Haudrechy, Arnaud; Baillieul, Fabienne; Clément, Christophe; Lins, Laurence; Allais, Florent; Ongena, Marc; Bouquillon, Sandrine; Deleu, Magali; Dorey, Stephan

2018-06-04

Stimulation of plant innate immunity by natural and synthetic elicitors is a promising alternative to conventional pesticides for a more sustainable agriculture. Sugar-based bolaamphiphiles are known for their biocompatibility, biodegradability and low toxicity. In this work, we show that Synthetic Rhamnolipid Bolaforms (SRBs) that have been synthesized by green chemistry trigger Arabidopsis innate immunity. Using structure-function analysis, we demonstrate that SRBs, depending on the acyl chain length, differentially activate early and late immunity-related plant defense responses and provide local increase in resistance to plant pathogenic bacteria. Our biophysical data suggest that SRBs can interact with plant biomimetic plasma membrane and open the possibility of a lipid driven process for plant-triggered immunity by SRBs.

First Results of ELM Triggering With a Multichamber Lithium Granule Injector Into EAST Discharges

DOE PAGES

Sun, Z.; Lunsford, R.; Maingi, R.; ...

2017-12-12

A critical challenge facing the basic long-pulse H-mode for ITER is to control edge-localized modes (ELMs). A new method using a multichamber lithium (Li) granule injector (LGI) for ELM triggering experiments has been developed in Experimental Advanced Superconducting Tokamak (EAST). First experimental results of the control of ELMs are obtained in EAST with a tungsten divertor. It is found that the injector has good capacities, i.e., allowing good flexibilities in granule size selection, injection rate, and injection velocity. In conclusion, LGI has successfully triggered ELMs during the H-mode. These results indicate the LGI would be a promising method to controlmore » ELMs in long-pulse steady-state tokamaks.« less

First Results of ELM Triggering With a Multichamber Lithium Granule Injector Into EAST Discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Z.; Lunsford, R.; Maingi, R.

A critical challenge facing the basic long-pulse H-mode for ITER is to control edge-localized modes (ELMs). A new method using a multichamber lithium (Li) granule injector (LGI) for ELM triggering experiments has been developed in Experimental Advanced Superconducting Tokamak (EAST). First experimental results of the control of ELMs are obtained in EAST with a tungsten divertor. It is found that the injector has good capacities, i.e., allowing good flexibilities in granule size selection, injection rate, and injection velocity. In conclusion, LGI has successfully triggered ELMs during the H-mode. These results indicate the LGI would be a promising method to controlmore » ELMs in long-pulse steady-state tokamaks.« less

Targeting myofascial taut bands by ultrasound.

PubMed

Thomas, Kisha; Shankar, Hariharan

2013-07-01

Myofascial pain syndrome (MPS) is a frequent diagnosis in chronic pain and is characterized by tender, taut bands known as trigger points. The trigger points are painful areas in skeletal muscle that are associated with a palpable nodule within a taut band of muscle fibers. Despite the prevalence of myofascial pain syndrome, diagnosis is based on clinical criteria alone. A growing body of evidence that suggests that taut bands are readily visualized under ultrasound-guided exam, especially when results are correlated with elastography, multidimensional imaging, and physical exam findings such as local twitch response. The actual image characteristic in B mode appears to be controversial. Ultrasonography provides an objective modality to assist with diagnosis and treatment of trigger points in the future.

FPGA-based trigger system for the LUX dark matter experiment

NASA Astrophysics Data System (ADS)

Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A. G.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O`Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Skulski, W.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yin, J.; Young, S. K.; Zhang, C.

2016-05-01

LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be > 99 % efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since its full underground deployment in early 2013. This document is an overview of the systems capabilities, its inner workings, and its performance.

Remote Triggering of Microseismicity in Antarctica

NASA Astrophysics Data System (ADS)

Ji, M.; Li, C.; Peng, Z.; Walter, J. I.

2017-12-01

It is well known that large distant earthquakes can trigger microearthquakes/tectonic tremors during or immediately following their surface waves. Globally, triggered seismicity is mostly found in active plate boundary regions. Recent studies have shown that icequakes in Antartica can also be triggered by teleseismic events. However, it is still not clear how widespread this phenomenon is and whether there are any connections between large earthquakes and subsequent glacial movements. In this study, we conduct a systematic search for remotely triggered activity in Antarctica following recent large earthquakes, including the 2004 Mw9.1 Sumatra, 2011 Mw9.1 Tohoku, 2012 Mw8.6 Indian Ocean and 2014-2015 Chile earthquakes. We download seismic data recorded at the POLENET (YT) and the Argentina Antarctica Network (AI) from the Incorporated Research Institutions for Seismology (IRIS) Data Management Center (DMC). We apply a 2-8 Hz band-pass-filter to the continuous waveforms and visually identify local events during and immediately after the large amplitude surface waves. Spectrograms are computed as additional tools to identify triggered seismicity and are further confirmed by comparing the signals before and after the distant mainshocks. So far we have identified possible triggered seismicity in both networks' area following the 2010 Chile and 2011 Tohoku earthquakes. Our next step is to apply a waveform matching method to automatically detect possible triggered seismicity and check through all the available networks in Antarctica for the last decades, which should help to better understand the potential interaction between large earthquakes and icequakes in this region.

Logarithmic entanglement lightcone in many-body localized systems

NASA Astrophysics Data System (ADS)

Deng, Dong-Ling; Li, Xiaopeng; Pixley, J. H.; Wu, Yang-Le; Das Sarma, S.

2017-01-01

We theoretically study the response of a many-body localized system to a local quench from a quantum information perspective. We find that the local quench triggers entanglement growth throughout the whole system, giving rise to a logarithmic lightcone. This saturates the modified Lieb-Robinson bound for quantum information propagation in many-body localized systems previously conjectured based on the existence of local integrals of motion. In addition, near the localization-delocalization transition, we find that the final states after the local quench exhibit volume-law entanglement. We also show that the local quench induces a deterministic orthogonality catastrophe for highly excited eigenstates, where the typical wave-function overlap between the pre- and postquench eigenstates decays exponentially with the system size.

Alumni Giving: A Case Study of the Factors That Influence Philanthropic Behavior of Alumni Donors of Historically Black Colleges and Universities

ERIC Educational Resources Information Center

Roy-Rasheed, Lupita D.

2012-01-01

This research project was a study of the philanthropic behavior of local alumni donors at two historically Black colleges and universities (HBCUs) in the South Central Region. Specifically, the research explored HBCUs' local alumni donors' experiences, perceptions, triggers, and motivations and how these factors influence alumni giving. This…

Dynamic triggering potential of large earthquakes recorded by the EarthScope U.S. Transportable Array using a frequency domain detection method

NASA Astrophysics Data System (ADS)

Linville, L. M.; Pankow, K. L.; Kilb, D. L.; Velasco, A. A.; Hayward, C.

2013-12-01

Because of the abundance of data from the Earthscope U.S. Transportable Array (TA), data paucity and station sampling bias in the US are no longer significant obstacles to understanding some of the physical parameters driving dynamic triggering. Initial efforts to determine locations of dynamic triggering in the US following large earthquakes (M ≥ 8.0) during TA relied on a time domain detection algorithm which used an optimized short-term average to long-term average (STA/LTA) filter and resulted in an unmanageably large number of false positive detections. Specific site sensitivities and characteristic noise when coupled with changes in detection rates often resulted in misleading output. To navigate this problem, we develop a frequency domain detection algorithm that first pre-whitens each seismogram and then computes a broadband frequency stack of the data using a three hour time window beginning at the origin time of the mainshock. This method is successful because of the broadband nature of earthquake signals compared with the more band-limited high frequency picks that clutter results from time domain picking algorithms. Preferential band filtering of the frequency stack for individual events can further increase the accuracy and drive the detection threshold to below magnitude one, but at general cost to detection levels across large scale data sets. Of the 15 mainshocks studied, 12 show evidence of discrete spatial clusters of local earthquake activity occurring within the array during the mainshock coda. Most of this activity is in the Western US with notable sequences in Northwest Wyoming, Western Texas, Southern New Mexico and Western Montana. Repeat stations (associated with 2 or more mainshocks) are generally rare, but when occur do so exclusively in California and Nevada. Notably, two of the most prolific regions of seismicity following a single mainshock occur following the 2009 magnitude 8.1 Samoa (Sep 29, 2009, 17:48:10) event, in areas with few or no known Quaternary faults and sparse historic seismicity. To gain a better understanding of the potential interaction between local events during the mainshock coda and the local stress changes induced by the passing surface waves, we juxtapose the local earthquake locations on maps of peak stress changes (e.g., radial, tangential and horizontal). Preliminary results reveal that triggering in the US is perhaps not as common as previously thought, and that dynamic triggering is most likely a more complicated interplay between physical parameters (e.g., amplitude threshold, wave orientation, tectonic environment, etc) than can be explained by a single dominant driver.

Technical Note: MR-visualization of interventional devices using transient field alterations and balanced steady-state free precession imaging.

PubMed

Eibofner, Frank; Martirosian, Petros; Würslin, Christian; Graf, Hansjörg; Syha, Roland; Clasen, Stephan

2015-11-01

In interventional magnetic resonance imaging, instruments can be equipped with conducting wires for visualization by current application. The potential of sequence triggered application of transient direct currents in balanced steady-state free precession (bSSFP) imaging is demonstrated. A conductor and a modified catheter were examined in water phantoms and in an ex vivo porcine liver. The current was switched by a trigger pulse in the bSSFP sequence in an interval between radiofrequency pulse and signal acquisition. Magnitude and phase images were recorded. Regions with transient field alterations were evaluated by a postprocessing algorithm. A phase mask was computed and overlaid with the magnitude image. Transient field alterations caused continuous phase shifts, which were separated by the postprocessing algorithm from phase jumps due to persistent field alterations. The overlaid images revealed the position of the conductor. The modified catheter generated visible phase offset in all orientations toward the static magnetic field and could be unambiguously localized in the ex vivo porcine liver. The application of a sequence triggered, direct current in combination with phase imaging allows conspicuous localization of interventional devices with a bSSFP sequence.

A dysregulation of glucose metabolism control is associated with carotid atherosclerosis in patients with coronary heart disease (CORDIOPREV-DIAB study)

USDA-ARS?s Scientific Manuscript database

Background and aims: Patients with coexisting coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM) are at high risk of cardiovascular recurrence, however, it is not well established whether they exhibit an increased intima-media thickness of both common carotid arteries (IMT-CC). Further...

Aortic valve replacement for aortic stenosis caused by alkaptonuria.

PubMed

Hiroyoshi, Junko; Saito, Aya; Panthee, Nirmal; Imai, Yasushi; Kawashima, Dai; Motomura, Noboru; Ono, Minoru

2013-03-01

We report a case of aortic stenosis associated with ochronosis in a 70-year-old man who underwent biologic aortic valve replacement. Intraoperative findings included ochronosis of a severely calcified pigmented aortic valve along with pigmentation of the intima of the aorta. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Pepper pathogenesis-related protein 4c is a plasma membrane-localized cysteine protease inhibitor that is required for plant cell death and defense signaling.

PubMed

Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

Xanthomonas campestris pv. vesicatoria (Xcv) type III effector AvrBsT triggers programmed cell death (PCD) and activates the hypersensitive response (HR) in plants. Here, we isolated and identified the plasma membrane localized pathogenesis-related (PR) protein 4c gene (CaPR4c) from pepper (Capsicum annuum) leaves undergoing AvrBsT-triggered HR cell death. CaPR4c encodes a protein with a signal peptide and a Barwin domain. Recombinant CaPR4c protein expressed in Escherichia coli exhibited cysteine protease-inhibitor activity and ribonuclease (RNase) activity. Subcellular localization analyses revealed that CaPR4c localized to the plasma membrane in plant cells. CaPR4c expression was rapidly and specifically induced by avirulent Xcv (avrBsT) infection. Transient expression of CaPR4c caused HR cell death in pepper leaves, which was accompanied by enhanced accumulation of H2 O2 and significant induction of some defense-response genes. Deletion of the signal peptide from CaPR4c abolished the induction of HR cell death, indicating a requirement for plasma membrane localization of CaPR4c for HR cell death. CaPR4c silencing in pepper disrupted both basal and AvrBsT-triggered resistance responses, and enabled Xcv proliferation in infected leaves. H2 O2 accumulation, cell-death induction, and defense-response gene expression were distinctly reduced in CaPR4c-silenced pepper. CaPR4c overexpression in transgenic Arabidopsis plants conferred greater resistance against infection by Pseudomonas syringae pv. tomato and Hyaloperonospora arabidopsidis. These results collectively suggest that CaPR4c plays an important role in plant cell death and defense signaling. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

A Distributed Synchronization and Timing System on the EAST Tokamak

NASA Astrophysics Data System (ADS)

Luo, Jiarong; Wu, Yichun; Shu, Yantai

2008-08-01

A key requirement for the EAST distributed control system (EASTDCS) is time synchronization to an accuracy of <1 mus. In 2006 a Distributed Synchronization and Timing System (DSTS) was set up, which is based on the ATmega128 AVR microcontroller and the Nut/OS embedded Real Time Operating System (RTOS). The DSTS provides the control and the data acquisition systems with reference clocks (0.01 Hz 10 MHz) and delayed trigger times ( 1 mus 4294 s). These are produced by a Core Module Unit (CMU) connected by optical fibres to many Local Synchronized Node Units (LSNU). The fibres provide immunity from electrical noise and are of equal length to match clock and trigger delays between systems. This paper describes the architecture of the DSTS on the EAST tokamak and provides an overview of the characteristics of the main and local units.

UBAT of UFFO/ Lomonosov: The X-Ray Space Telescope to Observe Early Photons from Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Jeong, S.; Panasyuk, M. I.; Reglero, V.; Connell, P.; Kim, M. B.; Lee, J.; Rodrigo, J. M.; Ripa, J.; Eyles, C.; Lim, H.; Gaikov, G.; Jeong, H.; Leonov, V.; Chen, P.; Castro-Tirado, A. J.; Nam, J. W.; Svertilov, S.; Yashin, I.; Garipov, G.; Huang, M.-H. A.; Huang, J.-J.; Kim, J. E.; Liu, T.-C.; Petrov, V.; Bogomolov, V.; Budtz-Jørgensen, C.; Brandt, S.; Park, I. H.

2018-02-01

The Ultra-Fast Flash Observatory (UFFO) Burst Alert and Trigger Telescope (UBAT) has been designed and built for the localization of transient X-ray sources such as Gamma Ray Bursts (GRBs). As one of main instruments in the UFFO payload onboard the Lomonosov satellite (hereafter UFFO/ Lomonosov), the UBAT's roles are to monitor the X-ray sky, to rapidly locate and track transient sources, and to trigger the slewing of a UV/optical telescope, namely Slewing Mirror Telescope (SMT). The SMT, a pioneering application of rapid slewing mirror technology has a line of sight parallel to the UBAT, allowing us to measure the early UV/optical GRB counterpart and study the extremely early moments of GRB evolution. To detect X-rays, the UBAT utilizes a 191.1 cm2 scintillation detector composed of Yttrium Oxyorthosilicate (YSO) crystals, Multi-Anode Photomultiplier Tubes (MAPMTs), and associated electronics. To estimate a direction vector of a GRB source in its field of view, it employs the well-known coded aperture mask technique. All functions are written for implementation on a field programmable gate array to enable fast triggering and to run the device's imaging algorithms. The UFFO/ Lomonosov satellite was launched on April 28, 2016, and is now collecting GRB observation data. In this study, we describe the UBAT's design, fabrication, integration, and performance as a GRB X-ray trigger and localization telescope, both on the ground and in space.

Observations of EMIC Triggered Emissions off the Magnetic Equatorial Plane

NASA Astrophysics Data System (ADS)

Grison, B.; Breuillard, H.; Santolik, O.; Cornilleau-Wehrlin, N.

2016-12-01

On 19/08/2005 Cluster spacecraft had their perigee close to the dayside of the Earth magnetic equatorial plane, at about 14 hours Magnetic Local Time. The spacecraft crossed the equator from the southern hemisphere toward the northern hemisphere. In the Southern hemisphere, at about -23° magnetic latitude (MLAT) and at distance of 5.25 Earth Radii from Earth, Cluster 3 observes an EMIC triggered emission between the He+ and the proton local gyrofrequencies. The magnetic waveform (STAFF instrument data) is transformed into the Fourier space for a study based on single value decomposition (SVD) analysis. The emission lasts about 30s. The emission frequency rises from 1Hz up to 1.9Hz. The emission polarization is left-hand, its coherence value is high and the propagation angle is field aligned (lower than 30º). The Poynting flux orientation could not be established. Based on previous study results, these properties are indicative of an observation in vicinity of the source region of the triggered emission. From our knowledge this is the first time that EMIC triggered emission are observed off the magnetic equator. In order to identify the source region we study two possibilities: a source region at higher latitudes than the observations (and particles orbiting in "Shabansky" orbits) and a source region close to the magnetic equatorial plane, as reported in previous studies. We propose to identify the source region from ray tracing analysis and to compare the observed propagation angle in several frequency ranges to the ray tracing results.

Effects of hydromechanical loading history and antecedent soil mechanical damage on shallow landslide triggering

NASA Astrophysics Data System (ADS)

Fan, Linfeng; Lehmann, Peter; Or, Dani

2015-10-01

Evidence suggests that the sudden triggering of rainfall-induced shallow landslides is preceded by accumulation of local internal failures in the soil mantle before their abrupt coalescence into a landslide failure plane. The mechanical status of a hillslope at any given time reflects competition between local damage accumulated during antecedent rainfall events and rates of mechanical healing (e.g., rebonding of microcracks and root regrowth). This dynamic interplay between damage accumulation and healing rates determines the initial mechanical state for landslide modeling. We evaluated the roles of these dynamic processes on landslide characteristics and patterns using a hydromechanical landslide-triggering model for a sequence of rainfall scenarios. The progressive nature of soil failure was represented by the fiber bundle model formalism that considers threshold strength of mechanical bonds linking adjacent soil columns and bedrock. The antecedent damage induced by prior rainfall events was expressed by the fraction of broken fibers that gradually regain strength or mechanically heal at rates specific to soil and roots. Results indicate that antecedent damage accelerates landslide initiation relative to pristine (undamaged) hillslopes. The volumes of first triggered landslides increase with increasing antecedent damage; however, for heavily damaged hillslopes, landslide volumes tend to decrease. Elapsed time between rainfall events allows mechanical healing that reduces the effects of antecedent damage. This study proposed a quantitative framework for systematically incorporating hydromechanical loading history and information on precursor events (e.g., such as recorded by acoustic emissions) into shallow landslide hazard assessment.

Triggered surface slips in the Salton Trough associated with the 1999 Hector Mine, California, earthquake

USGS Publications Warehouse

Rymer, M.J.; Boatwright, J.; Seekins, L.C.; Yule, J.D.; Liu, J.

2002-01-01

Surface fracturing occurred along the southern San Andreas, Superstition Hills, and Imperial faults in association with the 16 October 1999 (Mw 7.1) Hector Mine earthquake, making this at least the eighth time in the past 31 years that a regional earthquake has triggered slip along faults in the Salton Trough. Fractures associated with the event formed discontinuous breaks over a 39-km-long stretch of the San Andreas fault, from the Mecca Hills southeastward to Salt Creek and Durmid Hill, a distance from the epicenter of 107 to 139 km. Sense of slip was right lateral; only locally was there a minor (~1 mm) vertical component of slip. Dextral slip ranged from 1 to 13 mm. Maximum slip values in 1999 and earlier triggered slips are most common in the central Mecca Hills. Field evidence indicates a transient opening as the Hector Mine seismic waves passed the southern San Andreas fault. Comparison of nearby strong-motion records indicates several periods of relative opening with passage of the Hector Mine seismic wave-a similar process may have contributed to the field evidence of a transient opening. Slip on the Superstition Hills fault extended at least 9 km, at a distance from the Hector Mine epicenter of about 188 to 196 km. This length of slip is a minimum value, because we saw fresh surface breakage extending farther northwest than our measurement sites. Sense of slip was right lateral; locally there was a minor (~1 mm) vertical component of slip. Dextral slip ranged from 1 to 18 mm, with the largest amounts found distributed (or skewed) away from the Hector Mine earthquake source. Slip triggered on the Superstition Hills fault commonly is skewed away from the earthquake source, most notably in 1968, 1979, and 1999. Surface slip on the Imperial fault and within the Imperial Valley extended about 22 km, representing a distance from the Hector Mine epicenter of about 204 to 226 km. Sense of slip dominantly was right lateral; the right-lateral component of slip ranged from 1 to 19 mm. Locally there was a minor (~1-2 mm) vertical component of slip; larger proportions of vertical slip (up to 10 mm) occurred in Mesquite basin, where scarps indicate long-term oblique-slip motion for this part of the Imperial fault. Slip triggered on the Imperial fault appears randomly distributed relative to location along the fault and source direction. Multiple surface slips, both primary and triggered slip, indicate that slip repeatedly is small at locations of structural complexity.

Quantification of Urban Environment's Role in Slope Stability for Landslide Events.

NASA Astrophysics Data System (ADS)

Bozzolan, E.; Holcombe, E.; Wagener, T.; Pianosi, F.

2017-12-01

The combination of a rapid and unplanned urban development with a likely future climate change could significantly affect landslide occurrences in the humid tropics, where rainfall events of high intensity and duration are the dominant trigger for landslide risk. The attention of current landslide hazard studies is largely focussed on natural slope processes based on combinations of environmental factors, excluding the role of urbanisation on slope stability. This project aims to understand the relative influence of urbanisation features on local slope stability and to translate the findings to a wider region. Individual slopes are firstly analysed with the software CHASM, a physically based model which combines soil hydrology and slope stability assessment. Instead of relying on existing records, generally lacking for landslides, ranges of plausible preparatory (such as slope, cohesion, friction angles), triggering (rainfall) and aggravating factors (deforestation, house density and water network) are defined and possible combinations of these factors are created by sampling from those ranges. The influence of urban features on site hydrology and stability mechanisms are evaluated and then implemented in denser urban contexts, characteristic of unplanned settlements. The results of CHASMS can be transferred to regional maps in order to identify the areas belonging to the triggering combinations of factors previously found. In this way, areas susceptible to landslides can be detected not only in terms of natural factors but also in relation to the degree of urbanisation. Realistic scenarios can be extrapolated from the areas considered and then analysed again with CHASM. This permits to adapt (and improve) the initial variability ranges of the factors, creating a general-specific cycle able to identify the landslide susceptibility regions and outline a hazard map. Once the triggers are understood, possible consequences can be assessed and mitigation strategies can be evaluated. The ability to define local urban rainfall threshold for landslide slope stability helps the decision-making process to prioritize the areas of interest and locally define the main causes of instability.

A fundamental discussion of what triggers localized deformation in geological materials

NASA Astrophysics Data System (ADS)

Peters, Max; Paesold, Martin; Poulet, Thomas; Herwegh, Marco; Regenauer-Lieb, Klaus; Veveakis, Manolis

2015-04-01

Discontinuous or localized structures are often marked by the transition from a homogeneously deforming into a highly localized mode. This transition has extensively been described in ductile shear zones, folding and pinch-and-swell boudinage, in natural examples, rock deformation experiments and numerical simulations, at various scales. It is conventionally assumed that ductile instabilities, which act as triggers for localized deformation, exclusively arise from structural heterogeneities, i.e. geometric interactions or material imperfections. However, Hansen et al. (2012) concluded from recent laboratory experiments that localized deformation might arise out of steady-state conditions, where the size of initial perturbations was either insufficiently large to trigger localization, or these heterogeneities were simply negligible at the scale of observation. We therefore propose the existence of a principal localization phenomenon, which is based on the material-specific rate-dependency of deformation at elevated temperatures. The concept of strain localization out of a mechanical steady state in a homogeneous material at a critical material parameter and/or deformation rate has previously been discussed for engineering materials (Gruntfest, 1963) and frictional faults (Veveakis et al., 2010). We expand this theory to visco-plastic carbonate rocks, considering deformation conditions and mechanisms encountered in naturally deformed rocks. In the numerical simulation, we implement a grain-size evolution based on the Paleowattmeter scaling relationship of Austin & Evans (2007), which takes both grain size sensitive (diffusion) and insensitive (dislocation) creep combined with grain growth into account (Herwegh et al., 2014). Based on constant strain rate simulations carried out under isothermal boundary conditions, we explore the parameter space in order to obtain the criteria for localization. We determine the criteria for the onset of localization, i.e. the critical amount of dissipative work translated into heat over the diffusive capacity of the system by an instability study designed for such materials (Gruntfest, 1963). With respect to our numerical experiments, this critical parameter determines the timing when the entire amount of deformation energy translated into heat cannot be diffusively transported out of the system anymore. The resulting local temperature rise then induces strain localization. In contrast to classical shear heating scenarios with (catastrophic) thermal runaways, temperature variations of less than 1 K are sufficient for this localization mode to occur due to the balance between heat producing (e.g. dislocation creep) and consuming (grain growth) processes in the present setup. We demonstrate that this rise in latent heat is sufficient to provoke grain growth, operating as an endothermic reaction, stabilizing the simulated localized structure in turn. Various localized ductile structures, such as folded or boudinaged layers, can therefore be placed at the same material failure mode due to fundamental energy bifurcations triggered by dissipative work out of homogeneous state. Finally, we will discuss situations, in which structural heterogeneities are considered negligible and where the energy theory described here plays an underlying role by means of a comparison between numerical experiments and natural examples. REFERENCES Austin, N. and Evans, B. (2007). Paleowattmeters: A scaling relation for dynamically recrystallized grain size. Geology, 35. Gruntfest, I.J. (1963). Thermal feedback in liquid flow, plane shear at constant stress. Transactions of the Society of Rheology, 7. Hansen, L.N. and Zimmermann, M.E. and Dillman, A.M. and Kohlstedt, D.L (2012). Strain localization in olivine aggregates at high temperature: a laboratory comparison of constant-strain-rate and constant-stress boundary conditions. Earth and Planetary Science Letters, 333-334. Herwegh, M., Poulet, T., Karrech, A. and Regenauer-Lieb, K. (2014). From transient to steady state deformation and grain size: A thermodynamic approach using elasto-visco-plastic numerical modeling. Journal of Geophysical Research, 119. Veveakis, E., Alevizos, S. and Vardoulakis, I. (2010). Chemical reaction capping of thermal instability during shear of frictional faults. Journal of Mechanics and Physics of Solids, 58.

Threshold Switchable Particles (TSPs) To Control Internal Hemorrhage

DTIC Science & Technology

2016-09-01

hemorrhage at local sites. Four collaborating laboratories worked together under this contract to define threshold levels of activators of blood clotting...such that the candidate clotting activators will circulate in the blood at a concentration below the threshold necessary to trigger clotting, but...accumulation of the activators at sites of internal injury/bleeding will cause the local concentration of clotting activators to exceed the clotting

Tremor, remote triggering and earthquake cycle

NASA Astrophysics Data System (ADS)

Peng, Z.

2012-12-01

Deep tectonic tremor and episodic slow-slip events have been observed at major plate-boundary faults around the Pacific Rim. These events have much longer source durations than regular earthquakes, and are generally located near or below the seismogenic zone where regular earthquakes occur. Tremor and slow-slip events appear to be extremely stress sensitive, and could be instantaneously triggered by distant earthquakes and solid earth tides. However, many important questions remain open. For example, it is still not clear what are the necessary conditions for tremor generation, and how remote triggering could affect large earthquake cycle. Here I report a global search of tremor triggered by recent large teleseismic earthquakes. We mainly focus on major subduction zones around the Pacific Rim. These include the southwest and northeast Japan subduction zones, the Hikurangi subduction zone in New Zealand, the Cascadia subduction zone, and the major subduction zones in Central and South America. In addition, we examine major strike-slip faults around the Caribbean plate, the Queen Charlotte fault in northern Pacific Northwest Coast, and the San Andreas fault system in California. In each place, we first identify triggered tremor as a high-frequency non-impulsive signal that is in phase with the large-amplitude teleseismic waves. We also calculate the dynamic stress and check the triggering relationship with the Love and Rayleigh waves. Finally, we calculate the triggering potential with the local fault orientation and surface-wave incident angles. Our results suggest that tremor exists at many plate-boundary faults in different tectonic environments, and could be triggered by dynamic stress as low as a few kPas. In addition, we summarize recent observations of slow-slip events and earthquake swarms triggered by large distant earthquakes. Finally, we propose several mechanisms that could explain apparent clustering of large earthquakes around the world.

Therapeutic-Ultrasound-Triggered Shape Memory of a Melamine-Enhanced Poly(vinyl alcohol) Physical Hydrogel.

PubMed

Li, Guo; Yan, Qiang; Xia, Hesheng; Zhao, Yue

2015-06-10

Therapeutic-ultrasound-triggered shape memory was demonstrated for the first time with a melamine-enhanced poly(vinyl alcohol) (PVA) physical hydrogel. The addition of a small amount of melamine (up to 1.5 wt %) in PVA results in a strong hydrogel due to the multiple H-bonding between the two constituents. A temporary shape of the hydrogel can be obtained by deformation of the hydrogel (∼65 wt % water) at room temperature, followed by fixation of the deformation by freezing/thawing the hydrogel under strain, which induces crystallization of PVA. We show that the ultrasound delivered by a commercially available device designed for the patient's pain relief could trigger the shape recovery process as a result of ultrasound-induced local heating in the hydrogel that melts the crystallized PVA cross-linking. This hydrogel is thus interesting for potential applications because it combines many desirable properties, being mechanically strong, biocompatible, and self-healable and displaying the shape memory capability triggered by a physiological stimulus.

Tectonic tremor and LFEs on a reverse fault in Taiwan

DOE PAGES

Aguiar, Ana C.; Chao, Kevin; Beroza, Gregory C.

2017-06-16

In this paper, we compare low-frequency earthquakes (LFEs) from triggered and ambient tremor under the southern Central Range, Taiwan. We apply the PageRank algorithm used by Aguiar and Beroza (2014) that exploits the repetitive nature of the LFEs to find repeating LFEs in both ambient and triggered tremor. We use these repeaters to create LFE templates and find that the templates created from both tremor types are very similar. To test their similarity, we use both interchangeably and find that most of both the ambient and triggered tremor match the LFE templates created from either data set, suggesting that LFEsmore » for both events have a common origin. Finally, we locate the LFEs by using local earthquake P wave and S wave information and find that LFEs from triggered and ambient tremor locate to between 20 and 35 km on what we interpret as the deep extension of the Chaochou-Lishan Fault.« less

Lightning initiation mechanism based on the development of relativistic runaway electron avalanches triggered by background cosmic radiation: Numerical simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babich, L. P., E-mail: babich@elph.vniief.ru; Bochkov, E. I.; Kutsyk, I. M.

2011-05-15

The mechanism of lightning initiation due to electric field enhancement by the polarization of a conducting channel produced by relativistic runaway electron avalanches triggered by background cosmic radiation has been simulated numerically. It is shown that the fields at which the start of a lightning leader is possible even in the absence of precipitations are locally realized for realistic thundercloud configurations and charges. The computational results agree with the in-situ observations of penetrating radiation enhancement in thunderclouds.

How do you approach seizures in the high altitude traveler?

PubMed

Maa, Edward H

2011-01-01

Counseling patients who suffer first-time or break- through seizures can be difficult, particularly when controllable external factors may be contributing to the lowering of their seizure threshold. High altitude as a potential trigger for seizures is a common question in our epilepsy clinics in Colorado, and this article reviews the existing anecdotal literature, presents our local experience with high altitude seizures (HAS), offers possible mechanisms to explain how high altitude may trigger seizures, and suggests an initial work-up and prophylactic strategies for future high altitude exposures.

Enhancement of AGN Activity in Distant Galaxy Clusters

NASA Astrophysics Data System (ADS)

Krishnan, Charutha; Hatch, Nina; Almaini, Omar

2017-07-01

I present our recent study of the prevalence of X-ray AGN in the high-redshift protocluster Cl 0218.3-0510 at z=1.62, and review the implications for our understanding of galaxy evolution. There has long been a consensus that X-ray AGN avoid clusters in the local universe, particularly their cores. The high-redshift universe appears to not follow these trends, as there is a reversal in the local anti-correlation between galaxy density and AGN activity. In this z=1.62 protocluster, we find a large overdensity of AGN by a factor of 23, and an enhancement in the AGN fraction among massive galaxies relative to the field by a factor of 2. I will discuss the comparison of the properties of AGN in the protocluster to the field, and explain how our results point towards similar triggering mechanisms in the two environments. I will also describe how our study of the morphologies of these galaxies provide tentative evidence towards galaxy mergers and interactions being responsible for triggering AGN, and explain the reversal of the local anti-correlation between galaxy density and AGN activity.

FPGA-based trigger system for the LUX dark matter experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akerib, D. S.; Araújo, H. M.; Bai, X.

LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be >99% efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since its full underground deployment inmore » early 2013. This document is an overview of the systems capabilities, its inner workings, and its performance.« less

FPGA-based trigger system for the LUX dark matter experiment

DOE PAGES

Akerib, D. S.; Araújo, H. M.; Bai, X.; ...

2016-02-17

We present that LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be > 99% efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since itsmore » full underground deployment in early 2013. Finally, this document is an overview of the systems capabilities, its inner workings, and its performance.« less

FPGA-based trigger system for the LUX dark matter experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akerib, D. S.; Araújo, H. M.; Bai, X.

We present that LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be > 99% efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since itsmore » full underground deployment in early 2013. Finally, this document is an overview of the systems capabilities, its inner workings, and its performance.« less

Remotely triggered seismicity on the United States west coast following the Mw 7.9 Denali fault earthquake

USGS Publications Warehouse

Prejean, S.G.; Hill, D.P.; Brodsky, E.E.; Hough, S.E.; Johnston, M.J.S.; Malone, S.D.; Oppenheimer, D.H.; Pitt, A.M.; Richards-Dinger, K. B.

2004-01-01

The Mw 7.9 Denali fault earthquake in central Alaska of 3 November 2002 triggered earthquakes across western North America at epicentral distances of up to at least 3660 km. We describe the spatial and temporal development of triggered activity in California and the Pacific Northwest, focusing on Mount Rainier, the Geysers geothermal field, the Long Valley caldera, and the Coso geothermal field.The onset of triggered seismicity at each of these areas began during the Love and Raleigh waves of the Mw 7.9 wave train, which had dominant periods of 15 to 40 sec, indicating that earthquakes were triggered locally by dynamic stress changes due to low-frequency surface wave arrivals. Swarms during the wave train continued for ∼4 min (Mount Rainier) to ∼40 min (the Geysers) after the surface wave arrivals and were characterized by spasmodic bursts of small (M ≤ 2.5) earthquakes. Dynamic stresses within the surface wave train at the time of the first triggered earthquakes ranged from 0.01 MPa (Coso) to 0.09 MPa (Mount Rainier). In addition to the swarms that began during the surface wave arrivals, Long Valley caldera and Mount Rainier experienced unusually large seismic swarms hours to days after the Denali fault earthquake. These swarms seem to represent a delayed response to the Denali fault earthquake. The occurrence of spatially and temporally distinct swarms of triggered seismicity at the same site suggests that earthquakes may be triggered by more than one physical process.

Aftershocks and triggering processes in rock fracture

NASA Astrophysics Data System (ADS)

Davidsen, J.; Kwiatek, G.; Goebel, T.; Stanchits, S. A.; Dresen, G.

2017-12-01

One of the hallmarks of our understanding of seismicity in nature is the importance of triggering processes, which makes the forecasting of seismic activity feasible. These triggering processes by which one earthquake induces (dynamic or static) stress changes leading to potentially multiple other earthquakes are at the core relaxation processes. A specic example of triggering are aftershocks following a large earthquake, which have been observed to follow certain empirical relationships such as the Omori-Utsu relation. Such an empirical relation should arise from the underlying microscopic dynamics of the involved physical processes but the exact connection remains to be established. Simple explanations have been proposed but their general applicability is unclear. Many explanations involve the picture of an earthquake as a purely frictional sliding event. Here, we present experimental evidence that these empirical relationships are not limited to frictional processes but also arise in fracture zone formation and are mostly related to compaction-type events. Our analysis is based on tri-axial compression experiments under constant displacement rate on sandstone and granite samples using spatially located acoustic emission events and their focal mechanisms. More importantly, we show that event-event triggering plays an important role in the presence of large-scale or macrocopic imperfections while such triggering is basically absent if no signicant imperfections are present. We also show that spatial localization and an increase in activity rates close to failure do not necessarily imply triggering behavior associated with aftershocks. Only if a macroscopic crack is formed and its propagation remains subcritical do we observe significant triggering.

Numerical simulations (2D) on the influence of pre-existing local structures and seismic source characteristics in earthquake-volcano interactions

NASA Astrophysics Data System (ADS)

Farías, Cristian; Galván, Boris; Miller, Stephen A.

2017-09-01

Earthquake triggering of hydrothermal and volcanic systems is ubiquitous, but the underlying processes driving these systems are not well-understood. We numerically investigate the influence of seismic wave interaction with volcanic systems simulated as a trapped, high-pressure fluid reservoir connected to a fluid-filled fault system in a 2-D poroelastic medium. Different orientations and earthquake magnitudes are studied to quantify dynamic and static stress, and pore pressure changes induced by a seismic event. Results show that although the response of the system is mainly dominated by characteristics of the radiated seismic waves, local structures can also play an important role on the system dynamics. The fluid reservoir affects the seismic wave front, distorts the static overpressure pattern induced by the earthquake, and concentrates the kinetic energy of the incoming wave on its boundaries. The static volumetric stress pattern inside the fault system is also affected by the local structures. Our results show that local faults play an important role in earthquake-volcanic systems dynamics by concentrating kinetic energy inside and acting as wave-guides that have a breakwater-like behavior. This generates sudden changes in pore pressure, volumetric expansion, and stress gradients. Local structures also influence the regional Coulomb yield function. Our results show that local structures affect the dynamics of volcanic and hydrothermal systems, and should be taken into account when investigating triggering of these systems from nearby or distant earthquakes.

Integrated 3D view of postmating responses by the Drosophila melanogaster female reproductive tract, obtained by micro-computed tomography scanning

PubMed Central

Mattei, Alexandra L.; Riccio, Mark L.; Avila, Frank W.; Wolfner, Mariana F.

2015-01-01

Physiological changes in females during and after mating are triggered by seminal fluid components in conjunction with female-derived molecules. In insects, these changes include increased egg production, storage of sperm, and changes in muscle contraction within the reproductive tract (RT). Such postmating changes have been studied in dissected RT tissues, but understanding their coordination in vivo requires a holistic view of the tissues and their interrelationships. Here, we used high-resolution, multiscale micro-computed tomography (CT) scans to visualize and measure postmating changes in situ in the Drosophila female RT before, during, and after mating. These studies reveal previously unidentified dynamic changes in the conformation of the female RT that occur after mating. Our results also reveal how the reproductive organs temporally shift in concert within the confines of the abdomen. For example, we observed chiral loops in the uterus and in the upper common oviduct that relax and constrict throughout sperm storage and egg movement. We found that specific seminal fluid proteins or female secretions mediate some of the postmating changes in morphology. The morphological movements, in turn, can cause further changes due to the connections among organs. In addition, we observed apparent copulatory damage to the female intima, suggesting a mechanism for entry of seminal proteins, or other exogenous components, into the female’s circulatory system. The 3D reconstructions provided by high-resolution micro-CT scans reveal how male and female molecules and anatomy interface to carry out and coordinate mating-dependent changes in the female’s reproductive physiology. PMID:26041806

Effect of Acarbose on Long-Term Prognosis in Acute Coronary Syndromes Patients with Newly Diagnosed Impaired Glucose Tolerance

PubMed Central

Yun, Peng; Du, Ai-ming; Chen, Xue-jun; Liu, Jing-cheng; Xiao, Hu

2016-01-01

Objective. To investigate the effect of acarbose therapy on the long-term prognosis of patients with acute coronary syndromes (ACS) complicating newly diagnosed impaired glucose tolerance (IGT). Methodology. 135 patients hospitalized for ACS who had been newly diagnosed with IGT were randomly assigned to acarbose group (150 mg/day, n = 67) or control group (no acarbose, n = 68). All cases in each group were given the same elementary treatment. Mean follow-up was 2.3 years. The incidence of major adverse cardiovascular event (MACE) and carotid intima-middle thickness (CIMT) were statistically analyzed. Results. During the mean follow-up of 2.3 years, the risk of recurrent MACE in acarbose group was decreased significantly compared with that in control group (26.67% versus 46.88%, P < 0.05); at the same time, thickening of the CIMT was significantly slower than the control group ((1.28 ± 0.42) mm versus (1.51 ± 0.64) mm, P < 0.05). Conclusions. Acarbose can effectively reduce the risk of MACE in ACS patients with newly diagnosed IGT, simultaneously retarding the progression of carotid intima-media thickness. PMID:26770983

Model-Based Analysis of Flow-Mediated Dilation and Intima-Media Thickness

PubMed Central

Bartoli, G.; Menegaz, G.; Lisi, M.; Di Stolfo, G.; Dragoni, S.; Gori, T.

2008-01-01

We present an end-to-end system for the automatic measurement of flow-mediated dilation (FMD) and intima-media thickness (IMT) for the assessment of the arterial function. The video sequences are acquired from a B-mode echographic scanner. A spline model (deformable template) is fitted to the data to detect the artery boundaries and track them all along the video sequence. The a priori knowledge about the image features and its content is exploited. Preprocessing is performed to improve both the visual quality of video frames for visual inspection and the performance of the segmentation algorithm without affecting the accuracy of the measurements. The system allows real-time processing as well as a high level of interactivity with the user. This is obtained by a graphical user interface (GUI) enabling the cardiologist to supervise the whole process and to eventually reset the contour extraction at any point in time. The system was validated and the accuracy, reproducibility, and repeatability of the measurements were assessed with extensive in vivo experiments. Jointly with the user friendliness, low cost, and robustness, this makes the system suitable for both research and daily clinical use. PMID:19360110

[CHANGES OF CAROTID AND VERTEBRAL ARTERIES IN PATENTS WITH ARTERIAL HYPERTENSION AND HEPATOBILIARY PATHOLOGY].

PubMed

Polyakov, V Ya; Nikolaev, Yu A; Pegova, S V; Matsievskaya, T R; Obukhov, I V

2016-01-01

The study included 1172 patients (410 men and 762 women) at the mean age of 60.3 ± 10.4 years with grade I-II (stage I-II) arterial hypertension (AH) admitted to the clinic of Institute of Experimental Medicine. The patients were divided into 2 groups based on the results of clinical and laboratory diagnostics. Group 1 (n = 525) included patients with AH and hepatobiliary system (HBS) diseases, group 2 (n = 647) patients with AH without HBS diseases. The patients group 1 had a thicker intima-media complex of carotid arteries, higher peak systolic bloodflow rate in the internal and vertebral carotid arteries, more pronounced coiling of internal carotid arteries than patients of group 2. Patients with AH and HBS diseases exhibited correlation between bloodflow rate in external carotid arteries and atherogenicity coefficient. Duplex scanning of neck vessels of in patients with AH without HBS diseases revealed peculiar changes of the intima-media thickness and hemodynamically significant changes of the blood flow in the internal carotid arteries that may be of prognostic value in this nosological syntropy and require the personified approach to diagnostics, treatment, and prevention of these conditions.

Periodontal Diseases and Carotid Intima-Media Thickness in Bangladesh

PubMed Central

Wu, Fen; Chen, Yu; Demmer, Ryan T.; Parvez, Faruque; Paul, Rina Rani; Shaheen, Ishrat; Sarwar, Golam; Ahmed, Alauddin; Eunus, Mahbub; Ahsan, Nafiz; Habibullah, Nur Mohammad; Islam, Tariqul; Rundek, Tatjana; Ahsan, Habibul; Desvarieux, Moise

2016-01-01

Aim To evaluate the relationship between periodontal diseases and subclinical atherosclerosis in a younger and lean South Asian population. Methods We conducted a cross-sectional study in 917 subjects (mean age 46 years and mean body mass index 21.1 kg/m2) from the Health Effects of Arsenic Longitudinal Study in Bangladesh. Multivariate linear regression models were used to assess the associations between multiple clinical measures of periodontal diseases and carotid intima-media thickness (IMT). Results Mean attachment loss (AL) and percentage of sites with AL ≥ 4 mm (% AL ≥ 4) were associated with increased IMT. The IMT was 20.0-μm (95% CI: 2.2, 37.8) and 26.5-μm (95% CI: 8.9, 44.1) higher in those in the top quartile of mean AL (> 3.72 mm) and % AL ≥ 4 (> 58.4%), respectively, compared to those in the bottom quartile. In a subset of 366 subjects, mean AL was positively associated with plasma levels of matrix metalloproteinase-9 (P < 0.05) and soluble intercellular adhesion molecule-1 (P < 0.01). Conclusions Attachment loss was associated with subclinical atherosclerosis in this young and lean Bangladeshi population. Future prospective studies are needed to confirm this association. PMID:27394059

Regression of the carotid intima media thickness by propylthiouracil therapy in Graves' hyperthyroidism.

PubMed

Bilir, Cemil; Gökosmanoglu, Feyzi; Caliskan, Mustafa; Cinemre, Hakan; Akdemir, Ramazan

2012-04-01

One of the cardiovascular effects of hyperthyroidism is increased carotid intima media thickness (CIMT). The aim of this study is to investigate the CIMT in patients with Graves' hyperthyroidism and the effect of propylthiouracil (PTU) therapy on CIMT. Twenty-six patients with Graves' hyperthyroidism and 33 healthy controls were included in the study. CIMT was measured at the right and left external carotid arteries in every patient in both groups. CIMT was measured before and after the PTU therapy in patients with Graves' hyperthyroidism. There was a significant difference in CIMT between the group of Graves' hyperthyroid patients and the control group (0.72 versus 0.55 mm, P < 0.0001) at baseline. Twenty-five of 26 patients with Graves' disease were followed up for 18 months prospectively. Euthyroidism has been achieved in 21 patients. After 18 months of treatment, CIMT decreased significantly compared with the baseline values [0.84 (0.54-1.3) to 0.72 (0.50-1.2), change 0.12 mm, P < 0.001]. Graves' hyperthyroidism is associated with atherosclerosis as assessed by CIMT. Treatment of Graves' hyperthyroidism with PTU decreases the CIMT.

Medicolegal diagnostic value and clinical significance of traumatic incomplete tears of the basilar artery.

PubMed

Djokic, Vesna; Savic, Slobodan; Atanasijevic, Tatjana

2003-06-01

Ruptures of arteries of the vertebrobasilary system are relatively frequent in medicolegal practice, and their origin may be both natural and violent. Tears that affects the whole thickness of the basilar artery cause subarachnoid hemorrhage (SAH), with an often rapid fatal outcome. 1-3 However, in some situations, arterial tears may be incomplete, involving the intima or both the intima and the media, but with preserved adventitia. 1, 4 Although such incomplete tears are not the source of immediate subarachnoid bleeding, their presence may be important from both a medicolegal and a clinical point of view. The aim of this article is to point out the significance of incomplete tears of basilar artery as a possible diagnostic sign of traumatic origin of SAH as well as a certain mechanism of injury, which involves forcible hyperextension and rotational movements of the head. The authors also describe their method of performing longitudinal section of the basilar artery, both at autopsy and for histologic examination, which is convenient for identifying multiple transversal incomplete tears of this blood vessel. The article is based on the analysis of three cases from the autopsy material of the Institute of Forensic Medicine in Belgrade.

Admixture Mapping of Subclinical Atherosclerosis and Subsequent Clinical Events Among African Americans in Two Large Cohort Studies

PubMed Central

Shendre, Aditi; Wiener, Howard; Irvin, Marguerite R.; Zhi, Degui; Limdi, Nita A.; Overton, Edgar T.; Wassel, Christina L.; Divers, Jasmin; Rotter, Jerome I.; Post, Wendy S.; Shrestha, Sadeep

2017-01-01

Background Local ancestry may contribute to the disproportionate burden of subclinical and clinical cardiovascular disease (CVD) among admixed African Americans (AAs) compared to other populations, suggesting a rationale for admixture mapping. Methods and Results We estimated local European ancestry (LEA) using Local Ancestry Inference in adMixed Populations using Linkage Disequilibrium (LAMP-LD) and evaluated the association with common carotid artery intima-media thickness (cCIMT) using multivariable linear regression analysis among 1,554 AAs from the Multi-Ethnic Study of Atherosclerosis (MESA). We conducted secondary analysis to examine the significant cCIMT-LEA associations with clinical CVD events. We observed genome-wide significance in relation to cCIMT association with the secretion regulating guanine nucleotide exchange factor (SERGEF) gene (β=0.0137, P=2.98×10−4), also associated with higher odds of stroke (odds ratio (OR)=1.71, P=0.02). Several regions, in particular Ca2+-dependent secretion activator 1 (CADPS) gene region identified in MESA were also replicated in the Atherosclerosis Risk in Communities (ARIC) cohort. We observed other cCIMT-LEA regions associated with other clinical events, most notably the regions harboring creatine kinase, mitochondrial 2 (CKMT2) and Ras protein specific guanine nucleotide releasing factor 2 (RASGRF2) genes with all clinical events except stroke, the leucine rich repeat containing 3B (LRRC3B) gene with myocardial infarction, the protein arginine methyltransferase 3 (PRMT3) gene with stroke, and the lipoma high mobility group protein I-C (HMGIC) fusion partner-like 2 (LHFPL2) gene with hard and all coronary heart disease. Conclusions We identified several novel LEA regions, in addition to previously identified genomic regions, associated with cCIMT and CVD events among African Americans. PMID:28408707

Assessment of local carotid stiffness in seronegative and seropositive rheumatoid arthritis.

PubMed

Aslan, Abdullah Nabi; Şirin Özcan, Ayşe Nur; Erten, Şükran; Alsancak, Yakup; Durmaz, Tahir

2017-10-01

Rheumatoid arthritis (RA) is a chronic, inflammatory disease associated with increased risk of cardiovascular (CV) disease. Arterial stiffness (AS) is an independent predictor of CV events. This study aimed to analyse local carotid AS parameters in seronegative and seropositive RA patients. Of 347 consecutive RA patients, we selected specifically those who were free of established CV diseases and risk factors. As a result, 140 patients (126 women, 52.2 ± 10 years) and 140 healthy controls (122 women, 52.7 ± 8.0 years) were enrolled into this study. The common carotid AS was evaluated using radio frequency echo-tracking system to determine the local carotid pulse wave velocity (cPWV) and carotid intima-media thickness (cIMT). Based on rheumatoid factor (RF) and/or anti-citrullinated protein antibody (ACPA) positivity, RA patients were categorized into seronegative and seropositive subgroups. Carotid PWV was determined to be significantly higher in all patients and subgroups than controls (p < .001 for all). Although cIMT was similar between the patients, controls and seropositive subgroup, seronegative patients had significantly higher cIMT compared to controls (p = .035) and seropositive group (p = .010). Moreover, a significant positive correlation was found between cPWV and age (r: 0.603, p < .001), ESR (r: 0.297, p = .004), ACPA (r: 0.346, p = .001) and cIMT (r: 0.290, p = .005) in seropositive patients. RA per se is sufficient to cause arteriosclerosis in the absence of classical CV risk factors. However, arterial hypertrophy is only increased in seronegative patients but not in seropositive group.

Isoform-specific PKA dynamics revealed by dye-triggered aggregation and DAKAP1alpha-mediated localization in living cells.

PubMed

Martin, Brent R; Deerinck, Thomas J; Ellisman, Mark H; Taylor, Susan S; Tsien, Roger Y

2007-09-01

The tetracysteine sequence YRECCPGCCMWR fused to the N terminus of green fluorescent protein (GFP) self-aggregates upon biarsenical labeling in living cells or in vitro. Such dye-triggered aggregates form temperature-dependent morphologies and are dispersed by photobleaching. Fusion of the biarsenical aggregating GFP to the regulatory (R) or catalytic (C) subunit of PKA traps intact holoenzyme in compact fluorescent puncta upon biarsenical labeling. Contrary to the classical model of PKA activation, elevated cAMP does not allow RIalpha and Calpha to diffuse far apart unless the pseudosubstrate inhibitor PKI or locally concentrated substrate is coexpressed. However, RIIalpha releases Calpha upon elevated cAMP alone, dependent on autophosphorylation of the RIIalpha inhibitory domain. DAKAP1alpha overexpression induced R and C outer mitochondrial colocalization and showed similar regulation. Overall, effective separation of type I PKA is substrate dependent, whereas type II PKA dissociation relies on autophosphorylation.

Quantum computer games: quantum minesweeper

NASA Astrophysics Data System (ADS)

Gordon, Michal; Gordon, Goren

2010-07-01

The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical minesweeper the goal of the game is to discover all the mines laid out on a board without triggering them, in the quantum version there are several classical boards in superposition. The goal is to know the exact quantum state, i.e. the precise layout of all the mines in all the superposed classical boards. The player can perform three types of measurement: a classical measurement that probabilistically collapses the superposition; a quantum interaction-free measurement that can detect a mine without triggering it; and an entanglement measurement that provides non-local information. The application of the concepts taught by quantum minesweeper to one-way quantum computing are also presented.

Multi-mode clustering model for hierarchical wireless sensor networks

NASA Astrophysics Data System (ADS)

Hu, Xiangdong; Li, Yongfu; Xu, Huifen

2017-03-01

The topology management, i.e., clusters maintenance, of wireless sensor networks (WSNs) is still a challenge due to its numerous nodes, diverse application scenarios and limited resources as well as complex dynamics. To address this issue, a multi-mode clustering model (M2 CM) is proposed to maintain the clusters for hierarchical WSNs in this study. In particular, unlike the traditional time-trigger model based on the whole-network and periodic style, the M2 CM is proposed based on the local and event-trigger operations. In addition, an adaptive local maintenance algorithm is designed for the broken clusters in the WSNs using the spatial-temporal demand changes accordingly. Numerical experiments are performed using the NS2 network simulation platform. Results validate the effectiveness of the proposed model with respect to the network maintenance costs, node energy consumption and transmitted data as well as the network lifetime.

Acoustic localization of triggered lightning

NASA Astrophysics Data System (ADS)

Arechiga, Rene O.; Johnson, Jeffrey B.; Edens, Harald E.; Thomas, Ronald J.; Rison, William

2011-05-01

We use acoustic (3.3-500 Hz) arrays to locate local (<20 km) thunder produced by triggered lightning in the Magdalena Mountains of central New Mexico. The locations of the thunder sources are determined by the array back azimuth and the elapsed time since discharge of the lightning flash. We compare the acoustic source locations with those obtained by the Lightning Mapping Array (LMA) from Langmuir Laboratory, which is capable of accurately locating the lightning channels. To estimate the location accuracy of the acoustic array we performed Monte Carlo simulations and measured the distance (nearest neighbors) between acoustic and LMA sources. For close sources (<5 km) the mean nearest-neighbors distance was 185 m compared to 100 m predicted by the Monte Carlo analysis. For far distances (>6 km) the error increases to 800 m for the nearest neighbors and 650 m for the Monte Carlo analysis. This work shows that thunder sources can be accurately located using acoustic signals.

Radio Follow-Up of Gravitational-Wave Triggers during Advanced LIGO 01

DOE PAGES

Palliyaguru, N. T.; Corsi, Alessandra; Kasliwal, M. M.; ...

2016-09-28

We present radio follow-up observations carried out with the Karl G. Jansky Very Large Array during the first observing run (O1) of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). A total of three gravitational-wave triggers were followed-up during the ≈4 months of O1, from 2015 September to 2016 January. Two of these triggers, GW150914 and GW151226, are binary black hole (BH) merger events of high significance. A third trigger, G194575, was subsequently declared as an event of no interest (i.e., a false alarm). Our observations targeted selected optical transients identified by the intermediate Palomar Transient Factory in the Advanced LIGOmore » error regions of the three triggers, and a limited region of the gravitational-wave localization area of G194575 not accessible to optical telescopes due to Sun constraints, where a possible high-energy transient was identified. No plausible radio counterparts to GW150914 and GW151226 were found, in agreement with expectations for binary BH mergers. We show that combining optical and radio observations is key to identifying contaminating radio sources that may be found in the follow-up of gravitational-wave triggers, such as emission associated with star formation and active galactic nuclei. We discuss our results in the context of the theoretical predictions for radio counterparts to gravitational-wave transients, and describe our future plans for the radio follow-up of Advanced LIGO (and Virgo) triggers.« less

Lateral extrusion of a thermally weakened pluton overburden (Campiglia Marittima, Tuscany)

NASA Astrophysics Data System (ADS)

Vezzoni, Simone; Rocchi, Sergio; Dini, Andrea

2017-10-01

The ascent and emplacement of magmas in the upper crust modify the local pre-existing thermal and rheological settings. Such changes have important effects in producing anomalous structures, mass extrusion, rock fracturing, and in some conditions, hydrothermal mineralizations. In the Campiglia Marittima area, detailed field mapping led to the reconstruction of a local deformation history that overlaps, chronologically and spatially, with regional extension. This local deformation was triggered at the Miocene-Pliocene boundary by the intrusion of a monzogranitic pluton beneath a carbonate sedimentary sequence. The emplacement of the pluton produced a perturbation in the rheological behaviour of the carbonate host rocks, producing transient ductile conditions in the very shallow crust. The carbonate rocks were thermally weakened and flowed laterally, accumulating downslope of the pluton roof, mainly toward the east. As the thermal anomaly was decaying, the brittle-ductile boundary moved progressively back towards the pluton, and large tension gash-shaped volumes of fractured marble were generated. These fractured volumes were exploited by rising hydrothermal fluids generating sigmoidal skarn bodies and ore shoots. This work presents the Campiglia Marittima case study as a prime example of structural interference between regional extensional structures and local, lateral mass extrusion in a transient ductile rheological regime triggered by pluton emplacement.

Adaptive self-organization of Bali's ancient rice terraces.

PubMed

Lansing, J Stephen; Thurner, Stefan; Chung, Ning Ning; Coudurier-Curveur, Aurélie; Karakaş, Çağil; Fesenmyer, Kurt A; Chew, Lock Yue

2017-06-20

Spatial patterning often occurs in ecosystems as a result of a self-organizing process caused by feedback between organisms and the physical environment. Here, we show that the spatial patterns observable in centuries-old Balinese rice terraces are also created by feedback between farmers' decisions and the ecology of the paddies, which triggers a transition from local to global-scale control of water shortages and rice pests. We propose an evolutionary game, based on local farmers' decisions that predicts specific power laws in spatial patterning that are also seen in a multispectral image analysis of Balinese rice terraces. The model shows how feedbacks between human decisions and ecosystem processes can evolve toward an optimal state in which total harvests are maximized and the system approaches Pareto optimality. It helps explain how multiscale cooperation from the community to the watershed scale could persist for centuries, and why the disruption of this self-organizing system by the Green Revolution caused chaos in irrigation and devastating losses from pests. The model shows that adaptation in a coupled human-natural system can trigger self-organized criticality (SOC). In previous exogenously driven SOC models, adaptation plays no role, and no optimization occurs. In contrast, adaptive SOC is a self-organizing process where local adaptations drive the system toward local and global optima.

Lateral extrusion of a thermally weakened pluton overburden (Campiglia Marittima, Tuscany)

NASA Astrophysics Data System (ADS)

Vezzoni, Simone; Rocchi, Sergio; Dini, Andrea

2018-06-01

The ascent and emplacement of magmas in the upper crust modify the local pre-existing thermal and rheological settings. Such changes have important effects in producing anomalous structures, mass extrusion, rock fracturing, and in some conditions, hydrothermal mineralizations. In the Campiglia Marittima area, detailed field mapping led to the reconstruction of a local deformation history that overlaps, chronologically and spatially, with regional extension. This local deformation was triggered at the Miocene-Pliocene boundary by the intrusion of a monzogranitic pluton beneath a carbonate sedimentary sequence. The emplacement of the pluton produced a perturbation in the rheological behaviour of the carbonate host rocks, producing transient ductile conditions in the very shallow crust. The carbonate rocks were thermally weakened and flowed laterally, accumulating downslope of the pluton roof, mainly toward the east. As the thermal anomaly was decaying, the brittle-ductile boundary moved progressively back towards the pluton, and large tension gash-shaped volumes of fractured marble were generated. These fractured volumes were exploited by rising hydrothermal fluids generating sigmoidal skarn bodies and ore shoots. This work presents the Campiglia Marittima case study as a prime example of structural interference between regional extensional structures and local, lateral mass extrusion in a transient ductile rheological regime triggered by pluton emplacement.

Spatiotemporal dynamics of optogenetically induced and spontaneous seizure transitions in primary generalized epilepsy

PubMed Central

Truccolo, Wilson; Wang, Jing; Nurmikko, Arto V.

2014-01-01

Transitions into primary generalized epileptic seizures occur abruptly and synchronously across the brain. Their potential triggers remain unknown. We used optogenetics to causally test the hypothesis that rhythmic population bursting of excitatory neurons in a local neocortical region can rapidly trigger absence seizures. Most previous studies have been purely correlational, and it remains unclear whether epileptiform events induced by rhythmic stimulation (e.g., sensory/electrical) mimic actual spontaneous seizures, especially regarding their spatiotemporal dynamics. In this study, we used a novel combination of intracortical optogenetic stimulation and microelectrode array recordings in freely moving WAG/Rij rats, a model of absence epilepsy with a cortical focus in the somatosensory cortex (SI). We report three main findings: 1) Brief rhythmic bursting, evoked by optical stimulation of neocortical excitatory neurons at frequencies around 10 Hz, induced seizures consisting of self-sustained spike-wave discharges (SWDs) for about 10% of stimulation trials. The probability of inducing seizures was frequency-dependent, reaching a maximum at 10 Hz. 2) Local field potential power before stimulation and response amplitudes during stimulation both predicted seizure induction, demonstrating a modulatory effect of brain states and neural excitation levels. 3) Evoked responses during stimulation propagated as cortical waves, likely reaching the cortical focus, which in turn generated self-sustained SWDs after stimulation was terminated. Importantly, SWDs during induced and spontaneous seizures propagated with the same spatiotemporal dynamics. Our findings demonstrate that local rhythmic bursting of excitatory neurons in neocortex at particular frequencies, under susceptible ongoing brain states, is sufficient to trigger primary generalized seizures with stereotypical spatiotemporal dynamics. PMID:25552645

Red ear syndrome precipitated by a dietary trigger: a case report

PubMed Central

2014-01-01

Introduction Red ear syndrome is a rare condition characterized by episodic attacks of erythema of the ear accompanied by burning ear pain. Symptoms are brought on by touch, exertion, heat or cold, stress, neck movements and washing or brushing of hair. Diagnosis and treatment of this condition are challenging. The case we report here involves a woman whose symptoms were brought on by a dietary trigger: orange juice as well as stress, causing significant physical and psychological morbidity. Avoidance of triggers resulted in symptomatic improvement. Case presentation A 22-year-old Caucasian woman who was a student presented twice to our department with evolving symptoms, the first time with hyperacusis (abnormal sound sensitivity arising from within the auditory system to sounds of moderate volume), intermittent right tinnitus and subjective hearing difficulties. She presented five years later with highly distressing episodes of erythematous ears, which were associated with burning pain around the ear and temporal areas, and intolerance to noise. After keeping a symptom diary, she identified orange juice and stress as triggers of her symptoms. No local head and neck pathology was present. Investigations and imaging were negative. Avoidance of triggers led to great symptomatic improvement. To the best of our knowledge, dietary triggers have not previously been reported as a trigger for this syndrome. This case shows a direct temporal link to a dietary trigger and supports a primary pathogenesis. Recognition and management of primary headache disorder and simple dietary and lifestyle changes brought about symptomatic relief. Conclusion Red ear syndrome is a little-known clinical syndrome of unknown etiology and management. To the best of our knowledge, our present case report is the first to describe primary red ear syndrome triggered by orange juice. Clinical benefit derived from avoidance of this trigger, which is already known to precipitate migraines, gives some insight into the pathogenesis of red ear syndrome. PMID:25303997

RPC based 5D tracking concept for high multiplicity tracking trigger

NASA Astrophysics Data System (ADS)

Aielli, G.; Camarri, P.; Cardarelli, R.; Di Ciaccio, A.; Distante, L.; Liberti, B.; Paolozzi, L.; Pastori, E.; Santonico, R.

2017-01-01

The recently approved High Luminosity LHC project (HL-LHC) and the future colliders proposals present a challenging experimental scenario, dominated by high pileup, radiation background and a bunch crossing time possibly shorter than 5 ns. This holds as well for muon systems, where RPCs can play a fundamental role in the design of the future experiments. The RPCs, thanks to their high space-time granularity, allows a sparse representation of the particle hits, in a very large parametric space containing, in addition to 3D spatial localization, also the pulse time and width associated to the avalanche charge. This 5D representation of the hits can be exploited to improve the performance of complex detectors such as muon systems and increase the discovery potential of a future experiment, by allowing a better track pileup rejection and sharper momentum resolution, an effective measurement of the particle velocity, to tag and trigger the non-ultrarelativistic particles, and the detection local multiple track events in close proximity without ambiguities. Moreover, due to the fast response, typically for RPCs of the order of a few ns, this information can be provided promptly to the lowest level trigger. We will discus theoretically and experimentally the principles and performance of this original method.

Blood pressure control with selective vagal nerve stimulation and minimal side effects

NASA Astrophysics Data System (ADS)

Plachta, Dennis T. T.; Gierthmuehlen, Mortimer; Cota, Oscar; Espinosa, Nayeli; Boeser, Fabian; Herrera, Taliana C.; Stieglitz, Thomas; Zentner, Joseph

2014-06-01

Objective. Hypertension is the largest threat to patient health and a burden to health care systems. Despite various options, 30% of patients do not respond sufficiently to medical treatment. Mechanoreceptors in the aortic arch relay blood pressure (BP) levels through vagal nerve (VN) fibers to the brainstem and trigger the baroreflex, lowering the BP. Selective electrical stimulation of these nerve fibers reduced BP in rats. However, there is no technique described to localize and stimulate these fibers inside the VN without inadvertent stimulation of non-baroreceptive fibers causing side effects like bradycardia and bradypnea. Approach. We present a novel method for selective VN stimulation to reduce BP without the aforementioned side effects. Baroreceptor compound activity of rat VN (n = 5) was localized using a multichannel cuff electrode, true tripolar recording and a coherent averaging algorithm triggered by BP or electrocardiogram. Main results. Tripolar stimulation over electrodes near the barofibers reduced the BP without triggering significant bradycardia and bradypnea. The BP drop was adjusted to 60% of the initial value by varying the stimulation pulse width and duration, and lasted up to five times longer than the stimulation. Significance. The presented method is robust to impedance changes, independent of the electrode's relative position, does not compromise the nerve and can run on implantable, ultra-low power signal processors.

Overview of Emic Triggered Chorus Emissions in Cluster Data

NASA Astrophysics Data System (ADS)

Grison, B.; Pickett, J. S.; Omura, Y.; Santolik, O.; Engebretson, M. J.; Dandouras, I. S.; Masson, A.; Decreau, P. M.; Adrian, M. L.; Cornilleau Wehrlin, N.

2010-12-01

Electromagnetic ion cyclotron (EMIC) triggered emissions have been recently observed onboard the Cluster spacecraft close to the plasmapause in the equatorial region of the magnetosphere (Pickett et al., 2010). The nonlinear mechanism of the wave amplification is the same as for the well known whistler-mode chorus emissions (Omura et al., 2010). The EMIC triggered emissions appear as risers: electromagnetic structures that have a positive frequency drift with time. They can thus be considered as the EMIC analogue of rising frequency whistler-mode chorus emissions. In addition, they propagate away from the magnetic equator. These EMIC risers are not common in Cluster data. We present an overview of the properties of all the identified cases. Risers can be sorted out in two groups: in the first one the starting frequency of EMIC emissions is close to one half of the local proton gyrofrequency and the risers have a clear left-hand polarization. In the second group the risers have an opposite polarization with a starting frequency close to one half of the He+ gyrofrequency. Most of the cases have been detected close to 22 MLT (magnetic local time). This dependence will be investigated to determine if it is linked to the orbit effects or if there is a physical cause.

Earthquake triggering by seismic waves following the landers and hector mine earthquakes

USGS Publications Warehouse

Gomberg, J.; Reasenberg, P.A.; Bodin, P.; Harris, R.A.

2001-01-01

The proximity and similarity of the 1992, magnitude 7.3 Landers and 1999, magnitude 7.1 Hector Mine earthquakes in California permit testing of earthquake triggering hypotheses not previously possible. The Hector Mine earthquake confirmed inferences that transient, oscillatory 'dynamic' deformations radiated as seismic waves can trigger seismicity rate increases, as proposed for the Landers earthquake1-6. Here we quantify the spatial and temporal patterns of the seismicity rate changes7. The seismicity rate increase was to the north for the Landers earthquake and primarily to the south for the Hector Mine earthquake. We suggest that rupture directivity results in elevated dynamic deformations north and south of the Landers and Hector Mine faults, respectively, as evident in the asymmetry of the recorded seismic velocity fields. Both dynamic and static stress changes seem important for triggering in the near field with dynamic stress changes dominating at greater distances. Peak seismic velocities recorded for each earthquake suggest the existence of, and place bounds on, dynamic triggering thresholds. These thresholds vary from a few tenths to a few MPa in most places, depend on local conditions, and exceed inferred static thresholds by more than an order of magnitude. At some sites, the onset of triggering was delayed until after the dynamic deformations subsided. Physical mechanisms consistent with all these observations may be similar to those that give rise to liquefaction or cyclic fatigue.

A Parameterization for the Triggering of Landscape Generated Moist Convection

NASA Technical Reports Server (NTRS)

Lynn, Barry H.; Tao, Wei-Kuo; Abramopoulos, Frank

1998-01-01

A set of relatively high resolution three-dimensional (3D) simulations were produced to investigate the triggering of moist convection by landscape generated mesoscale circulations. The local accumulated rainfall varied monotonically (linearly) with the size of individual landscape patches, demonstrating the need to develop a trigger function that is sensitive to the size of individual patches. A new triggering function that includes the effect of landscapes generated mesoscale circulations over patches of different sizes consists of a parcel's perturbation in vertical velocity (nu(sub 0)), temperature (theta(sub 0)), and moisture (q(sub 0)). Each variable in the triggering function was also sensitive to soil moisture gradients, atmospheric initial conditions, and moist processes. The parcel's vertical velocity, temperature, and moisture perturbation were partitioned into mesoscale and turbulent components. Budget equations were derived for theta(sub 0) and q(sub 0). Of the many terms in this set of budget equations, the turbulent, vertical flux of the mesoscale temperature and moisture contributed most to the triggering of moist convection through the impact of these fluxes on the parcel's temperature and moisture profile. These fluxes needed to be parameterized to obtain theta(sub 0) and q(sub 0). The mesoscale vertical velocity also affected the profile of nu(sub 0). We used similarity theory to parameterize these fluxes as well as the parcel's mesoscale vertical velocity.

Rate of Change in Lake Level and its Impact on Reservoir-triggered Seismicity

NASA Astrophysics Data System (ADS)

Simpson, D. W.

2017-12-01

With recent interest in increased seismicity related to fluid injection, it is useful to review cases of reservoir-triggered earthquakes to explore common characteristics and seek ways to mitigate the influence of anthropogenic impacts. Three reservoirs - Koyna, India; Nurek, Tajikistan; and Aswan, Egypt - are well-documented cases of triggered earthquakes with recorded time series of seismicity and water levels that extend for more than 30 years. The geological setting, regional tectonics and modes of reservoir utilization, along with the characteristics of the reservoir-seismicity interaction, are distinctly different in each of these three cases. Similarities and differences between these three cases point to regional and local geological and hydrological structures and the rate of changes in reservoir water level as important factors controlling the presence and timing of triggered seismicity. In a manner similar to the way in which the rate of fluid injection influences injection-related seismicity, the rate of change in reservoir water level is a significant factor in determining whether or not reservoir-triggered seismicity occurs. The high rate of annual water level rise may be important in sustaining the exceptionally long sequence of earthquakes at Koyna. In addition to the rate of filling being a determining factor in whether or not earthquakes are triggered, changes in the rate of filling may influence the time of occurrence of individual earthquakes.

Seismology with Mermaids: Statistics from the Galapagos Experiment

NASA Astrophysics Data System (ADS)

Hello, Y.; Nolet, G.; Bonnieux, S.; Pazmino, A.; van der Lee, S.; Simons, F.; Chen, J.

2017-12-01

The operation of a small network of Mermaids for more than two years near the Galapagos Islands has provided with us the first experience of launching and following a mobile network of floating seismographs that transmit triggered signals by satellite (Rudics-Iridium).In mid 2014 we launched ten Mermaids of the first generation. The float that hosts the seismic instrumentation is an APEX float, the same as used by oceanographers in the Argo project.We lost contact with one of the floats after only one surfacing, in which it transmitted a time-depth history indicating a change of weight (leakage or fouling is suspected). The other nine surfaced on average 126 times before running out of power. They had an average lifespan of 616 days, with the longest lifespan 901 days. Earlier tests showed that power consumption is roughly divided equally between pump, CPU and transmission, and the large variety of lifespans indicate that unknown causes other than depletion of the battery may be at work, certainly in case of the one Mermaid that surfaced only 40 times.In total the nine Mermaids transmitted 1329 signals, of which 719 were associated with the arrival of an earthquake signal using our automatized data management software. Inspection by eye identified additional signals in the remaining records that are likely local earthquakes of small magnitude for which information in the catalogues is lacking, but most of them constitute false triggers.The success of a trigger depends very much on noise conditions that may be very local. The high frequency content of deep quakes makes them somewhat easier to identify than shallow ones. Teleseismic events with magnitudes higher than 5.5 can trigger successfully under quiet conditions, but even strong earthquakes can be missed during a storm. The experience with this first generation Mermaid has led us to develop the current version which has a larger battery capacity (expected lifespan 5 years) and the ability to recover missed triggers by commands via the satellite.

Site-specific to local-scale shallow landslides triggering zones assessment using TRIGRS

NASA Astrophysics Data System (ADS)

Bordoni, M.; Meisina, C.; Valentino, R.; Bittelli, M.; Chersich, S.

2015-05-01

Rainfall-induced shallow landslides are common phenomena in many parts of the world, affecting cultivation and infrastructure and sometimes causing human losses. Assessing the triggering zones of shallow landslides is fundamental for land planning at different scales. This work defines a reliable methodology to extend a slope stability analysis from the site-specific to local scale by using a well-established physically based model (TRIGRS-unsaturated). The model is initially applied to a sample slope and then to the surrounding 13.4 km2 area in Oltrepo Pavese (northern Italy). To obtain more reliable input data for the model, long-term hydro-meteorological monitoring has been carried out at the sample slope, which has been assumed to be representative of the study area. Field measurements identified the triggering mechanism of shallow failures and were used to verify the reliability of the model to obtain pore water pressure trends consistent with those measured during the monitoring activity. In this way, more reliable trends have been modelled for past landslide events, such as the April 2009 event that was assumed as a benchmark. The assessment of shallow landslide triggering zones obtained using TRIGRS-unsaturated for the benchmark event appears good for both the monitored slope and the whole study area, with better results when a pedological instead of geological zoning is considered at the regional scale. The sensitivity analyses of the influence of the soil input data show that the mean values of the soil properties give the best results in terms of the ratio between the true positive and false positive rates. The scheme followed in this work allows us to obtain better results in the assessment of shallow landslide triggering areas in terms of the reduction in the overestimation of unstable zones with respect to other distributed models applied in the past.

Ray tracing study of rising tone EMIC-triggered emissions

NASA Astrophysics Data System (ADS)

Hanzelka, Miroslav; Santolík, Ondřej; Grison, Benjamin; Cornilleau-Wehrlin, Nicole

2017-04-01

ElectroMagnetic Ion Cyclotron (EMIC) triggered emissions have been subject of extensive theoretical and experimental research in last years. These emissions are characterized by high coherence values and a frequency range of 0.5 - 2.0 Hz, close to local helium gyrofrequency. We perform ray tracing case studies of rising tone EMIC-triggered emissions observed by the Cluster spacecraft in both nightside and dayside regions off the equatorial plane. By comparison of simulated and measured wave properties, namely wave vector orientation, group velocity, dispersion and ellipticity of polarization, we determine possible source locations. Diffusive equilibrium density model and other, semi-empirical models are used with ion composition inferred from cross-over frequencies. Ray tracing simulations are done in cold plasma approximation with inclusion of Landau and cyclotron damping. Various widths, locations and profiles of plasmapause are tested.

Room temperature solid-state quantum emitters in the telecom range.

PubMed

Zhou, Yu; Wang, Ziyu; Rasmita, Abdullah; Kim, Sejeong; Berhane, Amanuel; Bodrog, Zoltán; Adamo, Giorgio; Gali, Adam; Aharonovich, Igor; Gao, Wei-Bo

2018-03-01

On-demand, single-photon emitters (SPEs) play a key role across a broad range of quantum technologies. In quantum networks and quantum key distribution protocols, where photons are used as flying qubits, telecom wavelength operation is preferred because of the reduced fiber loss. However, despite the tremendous efforts to develop various triggered SPE platforms, a robust source of triggered SPEs operating at room temperature and the telecom wavelength is still missing. We report a triggered, optically stable, room temperature solid-state SPE operating at telecom wavelengths. The emitters exhibit high photon purity (~5% multiphoton events) and a record-high brightness of ~1.5 MHz. The emission is attributed to localized defects in a gallium nitride (GaN) crystal. The high-performance SPEs embedded in a technologically mature semiconductor are promising for on-chip quantum simulators and practical quantum communication technologies.

Plant immunity triggered by microbial molecular signatures.

PubMed

Zhang, Jie; Zhou, Jian-Min

2010-09-01

Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) are recognized by host cell surface-localized pattern-recognition receptors (PRRs) to activate plant immunity. PAMP-triggered immunity (PTI) constitutes the first layer of plant immunity that restricts pathogen proliferation. PTI signaling components often are targeted by various Pseudomonas syringae virulence effector proteins, resulting in diminished plant defenses and increased bacterial virulence. Some of the proteins targeted by pathogen effectors have evolved to sense the effector activity by associating with cytoplasmic immune receptors classically known as resistance proteins. This allows plants to activate a second layer of immunity termed effector-triggered immunity (ETI). Recent studies on PTI regulation and P. syringae effector targets have uncovered new components in PTI signaling. Although MAP kinase (MAPK) cascades have been considered crucial for PTI, emerging evidence indicates that a MAPK-independent pathway also plays an important role in PTI signaling.

Defining the Relationship Between Biomarkers of Oxidative and Inflammatory Stress and the Risk for Atherosclerosis in Astronauts During and After Long-Duration Spaceflight

NASA Technical Reports Server (NTRS)

Lee, Stuart M. C.; Westby, Christian M.; Stenger, Michael B.; Ploutz-Snyder, Robert J.; Smith, Scott M.; Platts, Steven H.

2011-01-01

Future human space travel will primarily consist of long-duration missions aboard the International Space Station (ISS) or exploration class missions to Mars, its moons, or nearby asteroids. These missions will expose astronauts to increased risk of oxidative and inflammatory damage primarily from radiation, but also from psychological stress, reduced physical activity, diminished nutritional status, and, in the case of extravehicular activity, hyperoxic exposure. There is evidence that increased oxidative damage and inflammation can accelerate the development of atherosclerosis. PURPOSE The purpose of this proposal is to identify biomarkers of oxidative and inflammatory stress and to correlate them to indices of atherosclerosis risk before, during, and after long-duration spaceflight. METHODS To meet the objectives of the study, we will study astronauts before, during, and up to 5 years after long-duration missions aboard ISS. Biomarkers of oxidative and inflammatory stress, some of which we have previously shown to be elevated with spaceflight, will be measured before, during, and after spaceflight. Arterial structure will be monitored using ultrasound to measure carotid intima-medial thickness before, during, and after weightlessness. Carotid intima-medial thickness has been shown to be a better indicator than Framingham Risk scores for prediction of atherosclerosis. Arterial function will be monitored using brachial flow-mediated dilation before flight and after landing. Brachial flow-mediated dilation is a good index of endothelium-dependent vasodilation, which is a sensitive predictor of atherosclerotic risk. This is the first study to propose assessing atherosclerotic risk using biochemical, structural, and functional measures before, during, and immediately after spaceflight and structural functional measures for up to 5 years after landing. EXPECTED RESULTS We hypothesize that these biomarkers of oxidative and inflammatory stress will be increased with spaceflight and will correlate with increased carotid intima-medial thickness in- and postflight and with decreased flow-mediated dilation after the mission. Furthermore, we hypothesize that measures of oxidative stress will return to baseline after flight, but that biomarkers of inflammatory stress and vascular indices of atherosclerosis risk will remain elevated.

Identification of the BCAR1-CFDP1-TMEM170A locus as a determinant of carotid intima-media thickness and coronary artery disease risk.

PubMed

Gertow, Karl; Sennblad, Bengt; Strawbridge, Rona J; Ohrvik, John; Zabaneh, Delilah; Shah, Sonia; Veglia, Fabrizio; Fava, Cristiano; Kavousi, Maryam; McLachlan, Stela; Kivimäki, Mika; Bolton, Jennifer L; Folkersen, Lasse; Gigante, Bruna; Leander, Karin; Vikström, Max; Larsson, Malin; Silveira, Angela; Deanfield, John; Voight, Benjamin F; Fontanillas, Pierre; Sabater-Lleal, Maria; Colombo, Gualtiero I; Kumari, Meena; Langenberg, Claudia; Wareham, Nick J; Uitterlinden, André G; Gabrielsen, Anders; Hedin, Ulf; Franco-Cereceda, Anders; Nyyssönen, Kristiina; Rauramaa, Rainer; Tuomainen, Tomi-Pekka; Savonen, Kai; Smit, Andries J; Giral, Philippe; Mannarino, Elmo; Robertson, Christine M; Talmud, Philippa J; Hedblad, Bo; Hofman, Albert; Erdmann, Jeanette; Reilly, Muredach P; O'Donnell, Christopher J; Farrall, Martin; Clarke, Robert; Franzosi, Maria Grazia; Seedorf, Udo; Syvänen, Ann-Christine; Hansson, Göran K; Eriksson, Per; Samani, Nilesh J; Watkins, Hugh; Price, Jacqueline F; Hingorani, Aroon D; Melander, Olle; Witteman, Jacqueline C M; Baldassarre, Damiano; Tremoli, Elena; de Faire, Ulf; Humphries, Steve E; Hamsten, Anders

2012-12-01

Carotid intima-media thickness (cIMT) is a widely accepted marker of subclinical atherosclerosis. To date, large-scale investigations of genetic determinants of cIMT are sparse. To identify cIMT-associated genes and genetic variants, a discovery analysis using the Illumina 200K CardioMetabochip was conducted in 3430 subjects with detailed ultrasonographic determinations of cIMT from the IMPROVE (Carotid Intima Media Thickness [IMT] and IMT-Progression as Predictors of Vascular Events in a High Risk European Population) study. Segment-specific IMT measurements of common carotid, bifurcation, and internal carotid arteries, and composite IMT variables considering the whole carotid tree (IMT(mean), IMT(max), and IMT(mean-max)), were analyzed. A replication stage investigating 42 single-nucleotide polymorphisms for association with common carotid IMT was undertaken in 5 independent European cohorts (total n=11,590). A locus on chromosome 16 (lead single-nucleotide polymorphism rs4888378, intronic in CFDP1) was associated with cIMT at significance levels passing multiple testing correction at both stages (array-wide significant discovery P=6.75 × 10(-7) for IMT(max); replication P=7.24×10(-6) for common cIMT; adjustments for sex, age, and population substructure where applicable; minor allele frequency 0.43 and 0.41, respectively). The protective minor allele was associated with lower carotid plaque score in a replication cohort (P=0.04, n=2120) and lower coronary artery disease risk in 2 case-control studies of subjects with European ancestry (odds ratio [95% confidence interval] 0.83 [0.77-0.90], P=6.53 × 10(-6), n=13 591; and 0.95 [0.92-0.98], P=1.83 × 10(-4), n=82 297, respectively). Queries of human biobank data sets revealed associations of rs4888378 with nearby gene expression in vascular tissues (n=126-138). This study identified rs4888378 in the BCAR1-CFDP1-TMEM170A locus as a novel genetic determinant of cIMT and coronary artery disease risk in individuals of European descent.

Running multiple marathons is not a risk factor for premature subclinical vascular impairment.

PubMed

Pressler, Axel; Suchy, Christiane; Friedrichs, Tasja; Dallinger, Sophia; Grabs, Viola; Haller, Bernhard; Halle, Martin; Scherr, Johannes

2017-08-01

Background In contrast to the well-accepted benefits of moderate exercise, recent research has suggested potential deleterious effects of repeated marathon running on the cardiovascular system. We thus performed a comprehensive analysis of markers of subclinical vascular damage in a cohort of runners having finished multiple marathon races successfully. Design This was a prospective, observational study. Methods A total of 97 healthy male Munich marathon participants (mean age 44 ± 10 years) underwent detailed training history, cardiopulmonary exercise testing for assessment of peak oxygen uptake, ultrasound for assessment of intima-media-thickness as well as non-invasive assessments of ankle-brachial index, augmentation index, pulse wave velocity and reactive hyperaemia index. Results Runners had previously completed a median of eight (range 1-500) half marathons, six (1-100) full marathons and three (1-40) ultramarathons; mean weekly and annual training volumes were 59 ± 23 and 1639 ± 979 km. Mean peak oxygen uptake was 50 ± 8 ml/min/kg, and the Munich marathon was finished in 3:45 ± 0:32 h. Runners showed normal mean values for intima-media-thickness (0.60 ± 0.14 mm), ankle-brachial index (1.2 ± 0.1), augmentation index (17 ± 13%), pulse wave velocity (8.7 ± 1.4 cm/s) and reactive hyperaemia index (1.96 ± 0.50). Age was significantly and independently associated with intima-media-thickness ( r = 0.531; p < 0.001), augmentation index ( r = 0.593; p < 0.001) and pulse wave velocity ( r = 0.357; p < 0.001). However, no independent associations of peak oxygen uptake, marathon finishing time, number of completed races or weekly and annual training km with any of the vascular parameters were observed. Conclusions In this cohort of healthy male runners, running multiple marathon races did not pose an additional risk factor for premature subclinical vascular impairment beyond age.

Endothelial dysfunction assessment by flow-mediated dilation in a high-altitude population.

PubMed

Calderón-Gerstein, Walter S; López-Peña, Antonio; Macha-Ramírez, Raúl; Bruno-Huamán, Astrid; Espejo-Ramos, Roxana; Vílchez-Bravo, Stephany; Ramírez-Breña, María; Damián-Mucha, Milagros; Matos-Mucha, Adriana

2017-01-01

Endothelial function at high altitude has been measured only in populations that are genetically adapted to chronic hypoxia. The objective of this study was to evaluate endothelial dysfunction (ED) in a nongenetically adapted high-altitude population of the Andes mountains, in Huancayo, Peru (3,250 meters above sea level). Participants included 61 patients: 28 cases and 33 controls. The cases were subjects with hypertension, diabetes mellitus, obesity, or a history of stroke or coronary artery disease. Flow-mediated vasodilation (FMD) of the brachial artery was measured in the supine position, at noon, after 5 minutes of resting. The brachial artery was identified above the elbow. Its basal diameter was measured during diastole, and FMD was tested after 5 minutes of forearm ischemia. Intima-media complex in the right carotid artery was also determined. An increase in the artery's baseline diameter <10% indicated a positive test. Endothelium-independent vasodilation was evaluated with sublingual nitrate administration. The intima-media complex in the right carotid artery was also measured. 100% of diabetics had ED; ED was also found in 68.8% of obese individuals, 55% of hypertensive patients, and 46.5% of controls. Age, height, body mass index, and waist diameter were higher in the cases as compared with the controls. A total of 57.9% (n=11) of the cases and 45.2% (n=19) of the controls presented ED. Patients without ED had a mean increase in brachial artery diameter of 23.16%, while in those with ED it was only 3.84%. Individuals with diabetes or hypertension had a greater thickness of the carotid artery intima media layer (1.092 versus 0.664 cm) ( p =0.037). A positive test for ED was associated with a greater basal diameter of the brachial artery (4.66±0.62 versus 4.23±0.59 cm) ( p =0.02). A total of 7 patients presented paradoxical response, developing posthyperemia vasoconstriction. The proportion of ED was high among controls and among patients with risk factors. Controls showed better FMD profiles than subjects studied in Tibet and the Himalayas.

JTAG-based remote configuration of FPGAs over optical fibers

DOE PAGES

Deng, B.; Xu, H.; Liu, C.; ...

2015-01-28

In this study, a remote FPGA-configuration method based on JTAG extension over optical fibers is presented. The method takes advantage of commercial components and ready-to-use software such as iMPACT and does not require any hardware or software development. The method combines the advantages of the slow remote JTAG configuration and the fast local flash memory configuration. The method has been verified successfully and used in the Demonstrator of Liquid-Argon Trigger Digitization Board (LTDB) for the ATLAS liquid argon calorimeter Phase-I trigger upgrade. All components on the FPGA side are verified to meet the radiation tolerance requirements.

Iron Alkynyl Helicenes: Redox-Triggered Chiroptical Tuning in the IR and Near-IR Spectral Regions and Suitable for Telecommunications Applications.

PubMed

Shen, Chengshuo; Loas, Goulc'hen; Srebro-Hooper, Monika; Vanthuyne, Nicolas; Toupet, Loïc; Cador, Olivier; Paul, Frédéric; López Navarrete, Juan T; Ramírez, Francisco J; Nieto-Ortega, Belén; Casado, Juan; Autschbach, Jochen; Vallet, Marc; Crassous, Jeanne

2016-07-04

The combination of a bis-alkynyl-helicene moiety with two iron centers leads to novel electroactive species displaying unprecedented redox-triggered chiroptical switching. Upon oxidation, strong changes of vibrational modes (either local or extended coupled modes) are detected by vibrational circular dichroism and Raman optical activity. Remarkably, the sign of the optical rotation at 1.54 µm (that is, at wavelengths typically used for telecommunications) changes upon oxidation while the topology and stereochemistry of the helicene remain unchanged. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

78 FR 25236 - Approval and Promulgation of Implementation Plans; New York; Infrastructure SIP for the 1997 8...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-30

... enable the Commissioner to designate air pollution episodes which trigger the action plans. Pursuant to..., posts warnings on the above-referenced Web site and issues press releases to local media outlets if...

Corals diseases are a major cause of coral death

EPA Science Inventory

Corals, like humans, are susceptible to diseases. Some coral diseases are associated with pathogenic bacteria; however, the causes of most remain unknown. Some diseases trigger rapid and extensive mortality, while others slowly cause localized color changes or injure coral tiss...

Characterization of long-range functional connectivity in epileptic networks by neuronal spike-triggered local field potentials

NASA Astrophysics Data System (ADS)

Lopour, Beth A.; Staba, Richard J.; Stern, John M.; Fried, Itzhak; Ringach, Dario L.

2016-04-01

Objective. Quantifying the relationship between microelectrode-recorded multi-unit activity (MUA) and local field potentials (LFPs) in distinct brain regions can provide detailed information on the extent of functional connectivity in spatially widespread networks. These methods are common in studies of cognition using non-human animal models, but are rare in humans. Here we applied a neuronal spike-triggered impulse response to electrophysiological recordings from the human epileptic brain for the first time, and we evaluate functional connectivity in relation to brain areas supporting the generation of seizures. Approach. Broadband interictal electrophysiological data were recorded from microwires adapted to clinical depth electrodes that were implanted bilaterally using stereotactic techniques in six presurgical patients with medically refractory epilepsy. MUA and LFPs were isolated in each microwire, and we calculated the impulse response between the MUA on one microwire and the LFPs on a second microwire for all possible MUA/LFP pairs. Results were compared to clinical seizure localization, including sites of seizure onset and interictal epileptiform discharges. Main results. We detected significant interictal long-range functional connections in each subject, in some cases across hemispheres. Results were consistent between two independent datasets, and the timing and location of significant impulse responses reflected anatomical connectivity. However, within individual subjects, the spatial distribution of impulse responses was unique. In two subjects with clear seizure localization and successful surgery, the epileptogenic zone was associated with significant impulse responses. Significance. The results suggest that the spike-triggered impulse response can provide valuable information about the neuronal networks that contribute to seizures using only interictal data. This technique will enable testing of specific hypotheses regarding functional connectivity in epilepsy and the relationship between functional properties and imaging findings. Beyond epilepsy, we expect that the impulse response could be more broadly applied as a measure of long-range functional connectivity in studies of cognition.

Characterization of long-range functional connectivity in epileptic networks by neuronal spike-triggered local field potentials

PubMed Central

Lopour, Beth A; Staba, Richard J; Stern, John M; Fried, Itzhak; Ringach, Dario L

2017-01-01

Objective Quantifying the relationship between microelectrode-recorded multi-unit activity (MUA) and local field potentials (LFPs) in distinct brain regions can provide detailed information on the extent of functional connectivity in spatially widespread networks. These methods are common in studies of cognition using non-human animal models, but are rare in humans. Here we applied a neuronal spike-triggered impulse response to electrophysiological recordings from the human epileptic brain for the first time, and we evaluate functional connectivity in relation to brain areas supporting the generation of seizures. Approach Broadband interictal electrophysiological data were recorded from microwires adapted to clinical depth electrodes that were implanted bilaterally using stereotactic techniques in six presurgical patients with medically refractory epilepsy. MUA and LFPs were isolated in each microwire, and we calculated the impulse response between the MUA on one microwire and the LFPs on a second microwire for all possible MUA/LFP pairs. Results were compared to clinical seizure localization, including sites of seizure onset and interictal epileptiform discharges. Main results We detected significant interictal long-range functional connections in each subject, in some cases across hemispheres. Results were consistent between two independent datasets, and the timing and location of significant impulse responses reflected anatomical connectivity. However, within individual subjects, the spatial distribution of impulse responses was unique. In two subjects with clear seizure localization and successful surgery, the epileptogenic zone was associated with significant impulse responses. Significance The results suggest that the spike-triggered impulse response can provide valuable information about the neuronal networks that contribute to seizures using only interictal data. This technique will enable testing of specific hypotheses regarding functional connectivity in epilepsy and the relationship between functional properties and imaging findings. Beyond epilepsy, we expect that the impulse response could be more broadly applied as a measure of long-range functional connectivity in studies of cognition. PMID:26975603

Ambient Tremor, But No Triggered Tremor at the Northern Costa Rica Subduction Zone

NASA Astrophysics Data System (ADS)

Swiecki, Z.; Schwartz, S. Y.

2010-12-01

Non-volcanic tremor (NVT) has been found to be triggered during the passage of surface waves from various teleseismic events in locations around the world including Cascadia, Southwest Japan, Taiwan, and California. In this study we examine the northern Costa Rica subduction zone for evidence of triggered tremor. The Nicoya Peninsula segment of the northern Costa Rica margin experiences both slow-slip and tremor and is thus a prime candidate for triggered tremor observations. Eleven teleseismic events with magnitudes (Mw) greater than 8 occurring between 2006 and 2010 were examined using data from both broadband and short period sensors deployed on the Nicoya Peninsula, Costa Rica. Waveforms from several large regional events were also considered. The largest teleseismic and regional events (27 February 2010 Chile, Mw 8.8 and 28 May 2009 Honduras, Mw 7.3) induced peak ground velocities (PGV) at the NIcoya stations of ~2 and 6 mm/s, respectively; larger than PGVs in other locations that have triggered tremor. Many of the earthquakes examined occurred during small episodes of background ambient tremor. In spite of this, no triggered tremor was observed during the passage of seismic waves from any event. This is significant because other studies have demonstrated that NVT is not triggered everywhere by all events above some threshold magnitude, indicating that unique conditions are required for its occurrence. The lack of triggered tremor at the Costa Rica margin can help to better quantify the requisite conditions and triggering mechanisms. An inherent difference between the Costa Rica margin and the other subduction zones where triggered tremor exists is its erosional rather than accretionary nature. Its relatively low sediment supply likely results in a drier, lower pore fluid pressure, stronger and less compliant thrust interface that is less receptive to triggering tremor from external stresses generated by teleseismic or strong local earthquakes. Another important factor is Costa Rica’s relatively cool subduction zone structure where temperatures required for the fluid generating basalt/ecloginte reaction are not reached until far below tremor producing depths.

Progressive attenuation of the longitudinal kinetics in the common carotid artery: preliminary in vivo assessment.

PubMed

Zahnd, Guillaume; Balocco, Simone; Sérusclat, André; Moulin, Philippe; Orkisz, Maciej; Vray, Didier

2015-01-01

Longitudinal kinetics (LOKI) of the arterial wall consists of the shearing motion of the intima-media complex over the adventitia layer in the direction parallel to the blood flow during the cardiac cycle. The aim of this study was to investigate the local variability of LOKI amplitude along the length of the vessel. By use of a previously validated motion-estimation framework, 35 in vivo longitudinal B-mode ultrasound cine loops of healthy common carotid arteries were analyzed. Results indicated that LOKI amplitude is progressively attenuated along the length of the artery, as it is larger in regions located on the proximal side of the image (i.e., toward the heart) and smaller in regions located on the distal side of the image (i.e., toward the head), with an average attenuation coefficient of -2.5 ± 2.0%/mm. Reported for the first time in this study, this phenomenon is likely to be of great importance in improving understanding of atherosclerosis mechanisms, and has the potential to be a novel index of arterial stiffness. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Auxin acts as a local morphogenetic trigger to specify lateral root founder cells

PubMed Central

Dubrovsky, Joseph G.; Sauer, Michael; Napsucialy-Mendivil, Selene; Ivanchenko, Maria G.; Friml, Jiří; Shishkova, Svetlana; Celenza, John; Benková, Eva

2008-01-01

Plants exhibit an exceptional adaptability to different environmental conditions. To a large extent, this adaptability depends on their ability to initiate and form new organs throughout their entire postembryonic life. Plant shoot and root systems unceasingly branch and form axillary shoots or lateral roots, respectively. The first event in the formation of a new organ is specification of founder cells. Several plant hormones, prominent among them auxin, have been implicated in the acquisition of founder cell identity by differentiated cells, but the mechanisms underlying this process are largely elusive. Here, we show that auxin and its local accumulation in root pericycle cells is a necessary and sufficient signal to respecify these cells into lateral root founder cells. Analysis of the alf4–1 mutant suggests that specification of founder cells and the subsequent activation of cell division leading to primordium formation represent two genetically separable events. Time-lapse experiments show that the activation of an auxin response is the earliest detectable event in founder cell specification. Accordingly, local activation of auxin response correlates absolutely with the acquisition of founder cell identity and precedes the actual formation of a lateral root primordium through patterned cell division. Local production and subsequent accumulation of auxin in single pericycle cells induced by Cre-Lox-based activation of auxin synthesis converts them into founder cells. Thus, auxin is the local instructive signal that is sufficient for acquisition of founder cell identity and can be considered a morphogenetic trigger in postembryonic plant organogenesis. PMID:18559858

Lithium granule ablation and penetration during ELM pacing experiments at DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunsford, R.; Bortolon, A.; Roquemore, A. L.

At DIII-D, lithium granules were radially injected into the plasma at the outer midplane to trigger and pace edge localized modes (ELMs). Granules ranging in size from 300 to 1000 microns were horizontally launched into H-mode discharges with velocities near 100 m/s, and granule to granule injection frequencies less than 500 Hz. While the smaller granules were only successful in triggering ELMs approximately 20% of the time, the larger granules regularly demonstrated ELM triggering efficiencies of greater than 80%. A fast visible camera looking along the axis of injection observed the ablation of the lithium granules. We used the durationmore » of ablation as a benchmark for a neutral gas shielding calculation, and approximated the ablation rate and mass deposition location for the various size granules, using measured edge plasma profiles as inputs. In conclusion, this calculation suggests that the low triggering efficiency of the smaller granules is due to the inability of these granules to traverse the steep edge pressure gradient region and reach the top of the pedestal prior to full ablation.« less

The novel asymmetric entry intermediate of a picornavirus captured with nanodiscs

PubMed Central

Lee, Hyunwook; Shingler, Kristin L.; Organtini, Lindsey J.; Ashley, Robert E.; Makhov, Alexander M.; Conway, James F.; Hafenstein, Susan

2016-01-01

Many nonenveloped viruses engage host receptors that initiate capsid conformational changes necessary for genome release. Structural studies on the mechanisms of picornavirus entry have relied on in vitro approaches of virus incubated at high temperatures or with excess receptor molecules to trigger the entry intermediate or A-particle. We have induced the coxsackievirus B3 entry intermediate by triggering the virus with full-length receptors embedded in lipid bilayer nanodiscs. These asymmetrically formed A-particles were reconstructed using cryo-electron microscopy and a direct electron detector. These first high-resolution structures of a picornavirus entry intermediate captured at a membrane with and without imposing icosahedral symmetry (3.9 and 7.8 Å, respectively) revealed a novel A-particle that is markedly different from the classical A-particles. The asymmetric receptor binding triggers minimal global capsid expansion but marked local conformational changes at the site of receptor interaction. In addition, viral proteins extrude from the capsid only at the site of extensive protein remodeling adjacent to the nanodisc. Thus, the binding of the receptor triggers formation of a unique site in preparation for genome release. PMID:27574701

Lithium granule ablation and penetration during ELM pacing experiments at DIII-D

DOE PAGES

Lunsford, R.; Bortolon, A.; Roquemore, A. L.; ...

2016-05-25

At DIII-D, lithium granules were radially injected into the plasma at the outer midplane to trigger and pace edge localized modes (ELMs). Granules ranging in size from 300 to 1000 microns were horizontally launched into H-mode discharges with velocities near 100 m/s, and granule to granule injection frequencies less than 500 Hz. While the smaller granules were only successful in triggering ELMs approximately 20% of the time, the larger granules regularly demonstrated ELM triggering efficiencies of greater than 80%. A fast visible camera looking along the axis of injection observed the ablation of the lithium granules. We used the durationmore » of ablation as a benchmark for a neutral gas shielding calculation, and approximated the ablation rate and mass deposition location for the various size granules, using measured edge plasma profiles as inputs. In conclusion, this calculation suggests that the low triggering efficiency of the smaller granules is due to the inability of these granules to traverse the steep edge pressure gradient region and reach the top of the pedestal prior to full ablation.« less

Remotely triggered nonvolcanic tremor in Sumbawa, Indonesia

NASA Astrophysics Data System (ADS)

Fuchs, Florian; Lupi, Matteo; Miller, Stephen

2015-04-01

Nonvolcanic (or tectonic) tremor is a seismic phenomenom which can provide important information about dynamics of plate boundaries but the underlying mechanisms are not well understood. Tectonic tremor is often associated with slow-slip (termed episodic tremor and slip) and understanding the mechanisms driving tremor presents an important challenge because it is likely a dominant aspect of the evolutionary processes leading to tsunamigenic, megathrust subduction zone earthquakes. Tectonic tremor is observed worldwide, mainly along major subduction zones and plate boundaries such as in Alaska/Aleutians, Cascadia, the San Andreas Fault, Japan or Taiwan. We present, for the first time, evidence for triggered tremor beneath the island of Sumbawa, Indonesia. The island of Sumbawa, Indonesia, is part of the Lesser Sunda Group about 250 km north of the Australian/Eurasian plate collision at the Java Trench with a convergence rate of approximately 70 mm/yr. We show surface wave triggered tremor beneath Sumbawa in response to three teleseismic earthquakes: the Mw9.0 2011 Tohoku earthquake and two oceanic strike-slip earthquakes (Mw 8.6 and Mw8.2) offshore of Sumatra in 2012. Tremor amplitudes scale with ground motion and peak at 180 nm/s ground velocity on the horizontal components. A comparison of ground motion of the three triggering events and a similar (nontriggering) Mw7.6 2012 Philippines event constrains an apparent triggering threshold of approximately 1 mm/s ground velocity or 8 kPa dynamic stress. Surface wave periods of 45-65 s appear optimal for triggering tremor at Sumbawa which predominantly correlates with Rayleigh waves, even though the 2012 oceanic events have stronger Love wave amplitudes and triggering potential. Rayleigh wave triggering, low-triggering amplitudes, and the tectonic setting all favor a model of tremor generated by localized fluid transport. We could not locate the tremor because of minimal station coverage, but data indicate several potential source volumes including the Flores Thrust, the Java subduction zone, or Tambora volcano.

The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses

PubMed Central

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1–CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. PMID:25694549

The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses.

PubMed

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-04-01

The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1-CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Remote modulation of neural activities via near-infrared triggered release of biomolecules.

PubMed

Li, Wei; Luo, Rongcong; Lin, Xudong; Jadhav, Amol D; Zhang, Zicong; Yan, Li; Chan, Chung-Yuan; Chen, Xianfeng; He, Jufang; Chen, Chia-Hung; Shi, Peng

2015-10-01

The capability to remotely control the release of biomolecules provides an unique opportunity to monitor and regulate neural signaling, which spans extraordinary spatial and temporal scales. While various strategies, including local perfusion, molecular "uncaging", or photosensitive polymeric materials, have been applied to achieve controlled releasing of neuro-active substances, it is still challenging to adopt these technologies in many experimental contexts that require a straightforward but versatile loading-releasing mechanism. Here, we develop a synthetic strategy for remotely controllable releasing of neuro-modulating molecules. This platform is based on microscale composite hydrogels that incorporate polypyrrole (PPy) nanoparticles as photo-thermal transducers and is triggered by near-infrared-light (NIR) irradiation. Specifically, we first demonstrate the utility of our technology by recapitulating the "turning assay" and "collapse assay", which involve localized treatment of chemotactic factors (e.g. Netrin or Semaphorin 3A) to subcellular neural elements and have been extensively used in studying axonal pathfinding. On a network scale, the photo-sensitive microgels are also validated for light-controlled releasing of neurotransmitters (e.g. glutamate). A single NIR-triggered release is sufficient to change the dynamics of a cultured hippocampal neuron network. Taking the advantage of NIR's capability to penetrate deep into live tissue, this technology is further shown to work similarly well in vivo, which is evidenced by synchronized spiking activity in response to NIR-triggered delivery of glutamate in rat auditory cortex, demonstrating remote control of brain activity without any genetic modifications. Notably, our nano-composite microgels are capable of delivering various molecules, ranging from small chemicals to large proteins, without involving any crosslinking chemistry. Such great versatility and ease-of-use will likely make our optically-controlled delivery technology a general and important tool in cell biology research. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carotid Intima-Media Thickness Is Increased In Patients With Treated Mucopolysaccharidoses Types I and II, And Correlates With Arterial Stiffness

PubMed Central

Wang, Raymond Y.; Braunlin, Elizabeth A.; Rudser, Kyle D.; Dengel, Donald R.; Metzig, Andrea M.; Covault, Kelly K.; Polgreen, Lynda E.; Shapiro, Elsa; Steinberger, Julia; Kelly, Aaron S.

2013-01-01

Background Treatments for mucopolysaccharidoses (MPS) have increased longevity, but coronary artery disease (CAD) and cardiovascular complications cause mortality in a high percentage of patients. Non-invasive measures of sub-clinical atherosclerosis, such as carotid intima-media thickness (cIMT) and arterial stiffness, may be useful for prediction of CAD outcomes in MPS patients. Objectives To determine if cIMT and arterial stiffness are abnormal in MPS I and II patients compared to healthy controls. Methods MPS patients underwent carotid artery ultrasonography, and electronic wall-tracking software was used to measure cIMT, carotid artery compliance (cCSC), distensibility (cCSD), and incremental elastic modulus (cIEM). Control data from healthy subjects were obtained from a different study that utilized identical testing within the same laboratory. Results A total of 406 healthy controls and 25 MPS patients (16 MPS I, 9 MPS II) were studied. All MPS patients had or were receiving treatment: 15 patients (6 MPS I, 9 MPS II) were receiving enzyme replacement therapy (ERT), 9 patients (all MPS I) had received hematopoietic stem cell transplant (HSCT), and 1 patient with MPS I had received HSCT and was receiving enzyme replacement therapy (ERT). MPS patients had significantly higher mean (±SD) cIMT (0.56 ± 0.05 mm) compared to controls (0.44 ± 0.04 mm; adjusted p < 0.001). MPS patients also had increased stiffness compared to controls, showing significantly lower cCSC (0.14 ± 0.09 mm2/mmHg versus 0.16 ± 0.05 mm2/mmHg; adjusted p = 0.019), and higher cIEM (1362 ± 877 mmHg versus 942 ± 396 mmHg; adjusted p < 0.001). cCSD in MPS patients was lower than control (29.7 ± 16.4% versus 32.0 ± 8.2%) but was not statistically; p = 0.12. Among MPS patients, cCSD showed a significant association with cIMT (p = 0.047), while the association between cIEM and cIMT approached significance (p = 0.077). No significant differences were observed in cIMT, cCSD, cCSC, and cIEM between MPS I and MPS II patients. Conclusions Despite treatment, MPS patients had higher cIMT compared to healthy controls, indicating this marker of sub-clinical atherosclerosis may be a useful predictor of CAD outcomes. The association of arterial stiffness measures with cIMT suggests that mechanical and structural changes may occur in concert among MPS patients. Although yet to be confirmed, increased cIMT and arterial stiffness in MPS I and II patients may be a consequence of inflammatory signaling pathways triggered by heparan or dermatan sulfate-derived oligosaccharides. Prospective, longitudinal studies will need to be performed in order to evaluate the usefulness of these carotid measurements as predictors of adverse CAD outcomes in MPS patients. PMID:24268528

Reduction-Triggered Transformation of Crosslinking Modules of Disulfide-Containing Micelles with Chemically Tunable Rates.

PubMed

Deng, Zhengyu; Yuan, Shuai; Xu, Ronald X; Liang, Haojun; Liu, Shiyong

2018-05-16

A dilemma exists between the circulation stability and cargo release/mass diffusion at desired sites for designing delivery nanocarriers and in vivo nanoreactors. We herein report disulfide-crosslinked (DCL) micelles exhibiting reduction-triggered switching of crosslinking modules and synchronized hydrophobic-to-hydrophilic transition. Tumor cell-targeted DCL micelles undergo cytoplasmic milieu-triggered disulfide cleavage and cascade self-immolative decaging reactions at chemically adjustable rates, generating primary amine moieties. Extensive amidation reactions with neighboring ester moieties then occur due to high local concentrations and suppression of apparent amine pKa within hydrophobic cores, leading to the transformation of crosslinking modules and formation of tracelessly crosslinked (TCL) micelles with hydrophilic cores inside live cells. We further integrate this design principle with theranostic nanocarriers for selective intracellular drug transport guided by enhanced magnetic resonance (MR) imaging performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-IR-induced dissociation of thermally-sensitive star polymers.

PubMed

Dai, Yuqiong; Sun, Hao; Pal, Sunirmal; Zhang, Yunlu; Park, Sangwoo; Kabb, Christopher P; Wei, Wei David; Sumerlin, Brent S

2017-03-01

Responsive systems sensitive to near-infrared (NIR) light are promising for triggered release due to efficient deep tissue penetration of NIR irradiation relative to higher energy sources ( e.g. , UV), allowing for spatiotemporal control over triggering events with minimal potential for tissue damage. Herein, we report star polymers containing thermally-labile azo linkages that dissociate during conventional heating or during localized heating via the photothermal effect upon NIR irradiation. Controlled release during conventional heating was investigated for the star polymers loaded with a model dye, with negligible release being observed at 25 °C and >80% release at 90 °C. Star polymers co-loaded with NIR-responsive indocyanine green showed rapid dye release upon NIR irradiation ( λ ≥ 715 nm) due to the photothermally-induced degradation of azo linkages within the cores of the star polymers. This approach provides access to a new class of delivery and release systems that can be triggered by noninvasive external stimulation.

Estimation of sonodynamic treatment region with sonochemiluminescence in gel phantom

NASA Astrophysics Data System (ADS)

Mashiko, Daisaku; Nishitaka, Shinya; Iwasaki, Ryosuke; Lafond, Maxime; Yoshizawa, Shin; Umemura, Shin-ichiro

2018-07-01

Sonodynamic treatment is a non-invasive cancer treatment using ultrasound through the generation of reactive oxygen species (ROS) by acoustic cavitation. High-intensity focused ultrasound (HIFU) can generate cavitation bubbles using highly negative pressure in its focal region. When cavitation bubbles are forced to collapse, they generate ROS, which can attack cancer cells, typically assisted by a sonodynamically active antitumor agent. For sonodynamic treatment, both localization and efficiency of generating ROS are important. To improve them, the region of ROS generation was quantitatively estimated in this study using a polyacrylamide gel containing luminol as the target exposed to “Trigger HIFU”, consisting of a highly intense short “trigger pulse” to generate a cavitation cloud followed by a moderate-intensity long “sustaining burst” to keep the cavitation bubbles oscillating. It was found to be important for efficient ROS generation that the focal region of the trigger pulse should be immediately exposed to the sustaining burst.

Acoustic Response of Microbubbles Derived from Phase-Change Nanodroplet

NASA Astrophysics Data System (ADS)

Kawabata, Ken-ichi; Asami, Rei; Azuma, Takashi; Umemura, Shin-ichiro

2010-07-01

An in vitro feasibility test for a novel ultrasound therapy using a type of superheated perfluorocarbon droplet, phase-change nanodroplet (PCND), was performed in gel phantoms with the goal of high selectivity and low invasiveness. Measurements of broadband signal emission revealed that a triggering ultrasound pulse (peak negative pressure of 2.4 MPa) reduces the pressure threshold for cavitation induced by a subsequent ultrasound exposure at an order of magnitude from 2.4 to 0.2 MPa. The maximum allowed interval between the two ultrasound exposures for inducing cavitation with 100- and 1,000-cycle triggering ultrasound was about 100 and 500 ms, respectively. The echo signal increases induced by the triggering ultrasound with 100- and 1000-cycles were enhanced and suppressed by the subsequent ultrasound exposure, respectively. This different behavior seemed to be due to the presence of enlarged free bubbles, which should be avoided for the localization of therapeutic effects.

Room temperature solid-state quantum emitters in the telecom range

PubMed Central

Bodrog, Zoltán; Adamo, Giorgio; Gali, Adam

2018-01-01

On-demand, single-photon emitters (SPEs) play a key role across a broad range of quantum technologies. In quantum networks and quantum key distribution protocols, where photons are used as flying qubits, telecom wavelength operation is preferred because of the reduced fiber loss. However, despite the tremendous efforts to develop various triggered SPE platforms, a robust source of triggered SPEs operating at room temperature and the telecom wavelength is still missing. We report a triggered, optically stable, room temperature solid-state SPE operating at telecom wavelengths. The emitters exhibit high photon purity (~5% multiphoton events) and a record-high brightness of ~1.5 MHz. The emission is attributed to localized defects in a gallium nitride (GaN) crystal. The high-performance SPEs embedded in a technologically mature semiconductor are promising for on-chip quantum simulators and practical quantum communication technologies. PMID:29670945

Automatic Between-Pulse Analysis of DIII-D Experimental Data Performed Remotely on a Supercomputer at Argonne Leadership Computing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostuk, M.; Uram, T. D.; Evans, T.

For the first time, an automatically triggered, between-pulse fusion science analysis code was run on-demand at a remotely located supercomputer at Argonne Leadership Computing Facility (ALCF, Lemont, IL) in support of in-process experiments being performed at DIII-D (San Diego, CA). This represents a new paradigm for combining geographically distant experimental and high performance computing (HPC) facilities to provide enhanced data analysis that is quickly available to researchers. Enhanced analysis improves the understanding of the current pulse, translating into a more efficient use of experimental resources, and to the quality of the resultant science. The analysis code used here, called SURFMN,more » calculates the magnetic structure of the plasma using Fourier transform. Increasing the number of Fourier components provides a more accurate determination of the stochastic boundary layer near the plasma edge by better resolving magnetic islands, but requires 26 minutes to complete using local DIII-D resources, putting it well outside the useful time range for between pulse analysis. These islands relate to confinement and edge localized mode (ELM) suppression, and may be controlled by adjusting coil currents for the next pulse. Argonne has ensured on-demand execution of SURFMN by providing a reserved queue, a specialized service that launches the code after receiving an automatic trigger, and with network access from the worker nodes for data transfer. Runs are executed on 252 cores of ALCF’s Cooley cluster and the data is available locally at DIII-D within three minutes of triggering. The original SURFMN design limits additional improvements with more cores, however our work shows a path forward where codes that benefit from thousands of processors can run between pulses.« less

Automatic Between-Pulse Analysis of DIII-D Experimental Data Performed Remotely on a Supercomputer at Argonne Leadership Computing Facility

DOE PAGES

Kostuk, M.; Uram, T. D.; Evans, T.; ...

2018-02-01

For the first time, an automatically triggered, between-pulse fusion science analysis code was run on-demand at a remotely located supercomputer at Argonne Leadership Computing Facility (ALCF, Lemont, IL) in support of in-process experiments being performed at DIII-D (San Diego, CA). This represents a new paradigm for combining geographically distant experimental and high performance computing (HPC) facilities to provide enhanced data analysis that is quickly available to researchers. Enhanced analysis improves the understanding of the current pulse, translating into a more efficient use of experimental resources, and to the quality of the resultant science. The analysis code used here, called SURFMN,more » calculates the magnetic structure of the plasma using Fourier transform. Increasing the number of Fourier components provides a more accurate determination of the stochastic boundary layer near the plasma edge by better resolving magnetic islands, but requires 26 minutes to complete using local DIII-D resources, putting it well outside the useful time range for between pulse analysis. These islands relate to confinement and edge localized mode (ELM) suppression, and may be controlled by adjusting coil currents for the next pulse. Argonne has ensured on-demand execution of SURFMN by providing a reserved queue, a specialized service that launches the code after receiving an automatic trigger, and with network access from the worker nodes for data transfer. Runs are executed on 252 cores of ALCF’s Cooley cluster and the data is available locally at DIII-D within three minutes of triggering. The original SURFMN design limits additional improvements with more cores, however our work shows a path forward where codes that benefit from thousands of processors can run between pulses.« less

Earthquake-triggered landslides along the Hyblean-Malta Escarpment (off Augusta, eastern Sicily, Italy) - assessment of the related tsunamigenic potential

NASA Astrophysics Data System (ADS)

Ausilia Paparo, Maria; Armigliato, Alberto; Pagnoni, Gianluca; Zaniboni, Filippo; Tinti, Stefano

2017-02-01

Eastern Sicily is affected by earthquakes and tsunamis of local and remote origin, which is known through numerous historical chronicles. Recent studies have put emphasis on the role of submarine landslides as the direct cause of the main local tsunamis, envisaging that earthquakes (in 1693 and 1908) did produce a tsunami, but also that they triggered mass failures that were able to generate an even larger tsunami. The debate is still open, and though no general consensus has been found among scientists so far, this research had the merit to attract attention on possible generation of tsunamis by landslides off Sicily. In this paper we investigate the tsunami potential of mass failures along one sector of the Hyblean-Malta Escarpment (HME). facing Augusta. The HME is the main offshore geological structure of the region running almost parallel to the coast, off eastern Sicily. Here, bottom morphology and slope steepness favour soil failures. In our work we study slope stability under seismic load along a number of HME transects by using the Minimun Lithostatic Deviation (MLD) method, which is based on the limit-equilibrium theory. The main goal is to identify sectors of the HME that could be unstable under the effect of realistic earthquakes. We estimate the possible landslide volume and use it as input for numerical codes to simulate the landslide motion and the consequent tsunami. This is an important step for the assessment of the tsunami hazard in eastern Sicily and for local tsunami mitigation policies. It is also important in view of tsunami warning system since it can help to identify the minimum earthquake magnitude capable of triggering destructive tsunamis induced by landslides, and therefore to set up appropriate knowledge-based criteria to launch alert to the population.

Application of CO laser for laser balloon angioplasty

NASA Astrophysics Data System (ADS)

Miyamoto, Akira; Sakurada, Masami; Mizuno, Kyoichi; Kurita, Akira; Nakamura, Haruo; Suda, Akira; Arai, Tsunenori; Kikuchi, Makoto

1990-07-01

CO laser may be efficient for thermal fusion of intima of arterial wall without adventitial tissue damage because of high tissue absorption. To investigate the efficacy of CO laser as a laser bam for laser balloon angioplasty (LBA). CO laser was irradiated to aortic tissue through 3Oim polyethylene membrane and tissue temperature was measured by a thermistor. At 2Owatt/cm2 200joules/cm2 continuous laser exposure (CE), tissue temperature was above 100°C within a depth of 1mm and rapidly decreased to 60 °C or below between 2 and 3mm in depth. Moreover, adventitial temperature could be decreased by changing duty ratio (exposure duration/interval) of intermittent laser exposure (IE) despite of the same laser energy. Light microscopy showed high degree of medial coagulation necrosis in CE, however thermal coagulation was observed only at the surface of intima of aortic tissue in IE at duty ratio 1 / 2. These findings suggested CO laser could coagulate intimal layer with less deep thermal damage compared to Nd- YAG laser and that IE was better for superficial welding than CE at the same energy. We concluded that CO laser might be more efficient as a laser beam for LBA than Nd-YAG laser.

Triactome: Neuro–Immune–Adipose Interactions. Implication in Vascular Biology

PubMed Central

Chaldakov, George Nikov; Fiore, Marco; Ghenev, Peter I.; Beltowski, Jerzy; Ranćić, Gorana; Tunçel, Neşe; Aloe, Luigi

2014-01-01

Understanding how the precise interactions of nerves, immune cells, and adipose tissue account for cardiovascular and metabolic biology is a central aim of biomedical research at present. A long standing paradigm holds that the vascular wall is composed of three concentric tissue coats (tunicae): intima, media, and adventitia. However, large- and medium-sized arteries, where usually atherosclerotic lesions develop, are consistently surrounded by periadventitial adipose tissue (PAAT), we recently designated tunica adiposa (in brief, adiposa like intima, media, and adventitia). Today, atherosclerosis is considered an immune-mediated inflammatory disease featured by endothelial dysfunction/intimal thickening, medial atrophy, and adventitial lesions associated with adipose dysfunction, whereas hypertension is characterized by hyperinnervation-associated medial thickening due to smooth muscle cell hypertrophy/hyperplasia. PAAT expansion is associated with increased infiltration of immune cells, both adipocytes and immunocytes secreting pro-inflammatory and anti-inflammatory (metabotrophic) signaling proteins collectively dubbed adipokines. However, the role of vascular nerves and their interactions with immune cells and paracrine adipose tissue is not yet evaluated in such an integrated way. The present review attempts to briefly highlight the findings in basic and translational sciences in this area focusing on neuro–immune–adipose interactions, herein referred to as triactome. Triactome-targeted pharmacology may provide a novel therapeutic approach in cardiovascular disease. PMID:24782857

Androgen excess is associated with the increased carotid intima-media thickness observed in young women with polycystic ovary syndrome.

PubMed

Luque-Ramírez, Manuel; Mendieta-Azcona, Covadonga; Alvarez-Blasco, Francisco; Escobar-Morreale, Héctor F

2007-12-01

We evaluated carotid intima-media thickness (CIMT) as an early marker of atherosclerosis, as well as its main determinants among androgen excess, obesity and insulin resistance, in patients with polycystic ovary syndrome (PCOS). We selected 40 PCOS patients and 20 non-hyperandrogenic women who were similar in terms of age and grade of obesity. Complete clinical, metabolic and hormonal profiles and left common CIMT measurements were obtained. Patients with PCOS presented with increased mean CIMT values when compared with controls (F = 8.575; P = 0.005), and this was independent of obesity. Five PCOS patients but no controls had increased CIMT values. CIMT correlated directly with serum total and free testosterone, androstenedione and dehydroepiandrosterone-sulfate levels and mean 24-h heart rate (HR), and inversely with the insulin sensitivity index (ISI), but no correlation was observed with the body mass index (BMI). Multiple stepwise linear regression models showed that in PCOS patients, the main determinants of CIMT were serum total testosterone or androstenedione concentrations, with no influence of ISI or the mean 24-h HR. Compared with control women, PCOS patients present with an increased CIMT, independent of obesity and related directly to androgen excess; this suggests that hyperandrogenism is associated with atherosclerosis and cardiovascular risk in these women.

White blood cell subsets are associated with carotid intima-media thickness and pulse wave velocity in an older Chinese population: the Guangzhou Biobank Cohort Study.

PubMed

Phillips, A C; Jiang, C Q; Thomas, G N; Lin, J M; Yue, X J; Cheng, K K; Jin, Y L; Zhang, W S; Lam, T H

2012-08-01

Cross-sectional associations between white blood cell (WBC) count, lymphocyte and granulocyte numbers, and carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (PWV) were examined in a novel older Chinese community sample. A total of 817 men and 760 women from a sub-study of the Guangzhou Biobank Cohort Study had a full blood count measured by an automated hematology analyzer, carotid IMT by B-mode ultrasonography and brachial-ankle PWV by a non-invasive automatic waveform analyzer. Following adjustment for confounders, WBC count (β=0.07, P<0.001) and granulocyte (β=0.07, P<0.001) number were significantly positively related to PWV, but not lymphocyte number. Similarly, WBC count (β=0.08, P=0.03), lymphocyte (β=0.08, P=0.002) and granulocyte (β=0.03, P=0.04) number were significantly positively associated with carotid IMT, but only the association with lymphocyte count survived correction for other cardiovascular risk factors. In conclusion, higher WBC, particularly lymphocyte and granulocyte, count could be used, respectively, as markers of cardiovascular disease risk, measured through indicators of atherosclerosis and arterial stiffness. The associations for WBC count previously observed by others were likely driven by higher granulocytes; an index of systemic inflammation.

[ASSOCIATION BETWEEN DIETARY GLYCEMIC INDEX AND GLYCEMIC LOAD AND INTIMA MEDIA THICKNESS IN A POPULATION AT HIGH CARDIOVASCULAR RISK: A SUBGROUP ANALYSIS IN THE PREDIMED TRIAL].

PubMed

Goñi Ruiz, Nuria; Martínez González, Miguel Ángel; Salas Salvadó, Jordi; Buil Cosiales, Pilar; Diez Espino, Javier; Martinez Vila, Eduardo; Irimia Sierra, Pablo; Ros Rahola, Emilio; Toledo Atucha, Estefania

2015-11-01

increased carotid íntima-media thickness (IMT) is a marker of atherosclerosis and a predictor of future cardiovascular events. Although a beneficial effect of Mediterranean diets, in particular, enhanced with virgin olive oil and nuts, on longitudinal changes in IMT has been reported, the association between carbohydrates and the development of atherosclerosis is still unclear. to assess the association between glycemic index (IG) and glycemic load (CG) of the diet and intima media thickness (GIMC) in a population at high cardiovascular risk with no clinical symptoms. one hundred eighty seven participants of the PREDIMED-NAVARRA center (PREDIMED means in Spanish "PREvención con DIeta MEDiterránea") were randomly selected to undergo baseline and 1-year measurement of GIMC. Dietary information was collected at baseline and yearly using a validated 137-item food frequency questionnaire. Participants were categorized into four groups of energy-adjusted IG and CG intake. Multivariate analysis models (ANCOVA) were used to study the association between dietary IG and CG and GIMC and its changes. in our study we found no significant association between IG or CG and GIMC at baseline or after one year. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Copeptin, a surrogate marker for arginine vasopressin, is associated with cardiovascular risk in patients with polycystic ovary syndrome.

PubMed

Karbek, Basak; Ozbek, Mustafa; Karakose, Melia; Topaloglu, Oya; Bozkurt, Nujen Colak; Cakır, Evrim; Aslan, Muyesser Sayki; Delibasi, Tuncay

2014-03-14

Women with polycystic ovary syndrome (PCOS) have higher risk for cardiovascular disease (CVD). Copeptin has been found to be predictive for myocardial ischemia. We tested whether copeptin is the predictor for CVD in PCOS patients, who have an increased risk of cardiovascular disease. This was a cross sectional controlled study conducted in a training and research hospital. The study population consisted of 40 reproductive-age PCOS women and 43 control subjects. We evaluated anthropometric and metabolic parameters, carotid intima media thickness and copeptin levels in both PCOS patients and control group. Mean fasting insulin, homeostasis model assessment insulin resistance index (HOMA-IR), triglyceride, total cholesterol, low density lipoprotein cholesterol (LDL-C), free testosterone, 17-OH progesterone, Dehydroepiandrosterone sulfate (DHEAS), carotid intima media thickness (CIMT) levels were significantly higher in PCOS patients. Mean copeptin level was in 12.61 ± 3.05 pmol/L in PCOS patients while mean copeptin level was 9.60 ± 2.80 pmol/L in healthy control women (p < 0.001). After adjustment for age and BMI, copeptin level was positive correlated with fasting insulin, free testosterone levels, CIMT, and HOM A-IR. Copeptin appeared to have an important role in metabolic response and subsequent development of atherosclerosis in insulin resistant, hyperandrogenemic PCOS patients.

Residential Exposure to Urban Traffic Is Associated with Increased Carotid Intima-Media Thickness in Children

PubMed Central

Armijos, Rodrigo X.; Weigel, M. Margaret; Myers, Orrin B.; Li, Wen-Whai; Racines, Marcia; Berwick, Marianne

2015-01-01

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure. The multivariable analyses revealed that children residing <100 meters from the nearest heavily trafficked road had cIMT mean and maximum measurements that were increased by 15% and 11% compared to those living ≥ 200 meters away (P = 0.0001). Similar increases in cIMT were identified for children in the highest versus lowest DWTD tertile. Children who resided 100–199 meters from traffic or in the middle DWTD tertile also exhibited increased cIMT but these differences were not statistically significant. No statistically significant differences were identified between residential distance to traffic or DWTD and systemic inflammation indicators (CRP, IL-6). The study results suggest that exposure to urban traffic promotes arterial remodeling in children. This finding is important since even small increases in cIMT over time can potentially lead to earlier progression to atherosclerosis. It is also important because traffic-related pollution is potentially modifiable. PMID:25685160

Heart type fatty acid binding protein response and subsequent development of atherosclerosis in insulin resistant polycystic ovary syndrome patients.

PubMed

Cakir, Evrim; Ozbek, Mustafa; Sahin, Mustafa; Cakal, Erman; Gungunes, Askin; Ginis, Zeynep; Demirci, Taner; Delibasi, Tuncay

2012-12-18

Women with polycystic ovary syndrome (PCOS) have higher risk for cardiovascular disease (CVD). Heart type fatty acid binding protein (HFABP) has been found to be predictive for myocardial ischemia.Wet ested whether HFABP is the predictor for CVD in PCOS patients, who have an increased risk of cardiovascular disease. This was a prospective, cross sectional controlled study conducted in a training and research hospital.The study population consisted of 46 reproductive-age PCOS women and 28 control subjects. We evaluated anthropometric and metabolic parameters, carotid intima media thickness and HFABP levels in both PCOS patients and control group. Mean fasting insulin, homeostasis model assessment insulin resistance index (HOMA-IR), triglyceride, total cholesterol, low density lipoprotein cholesterol, free testosterone, total testosterone, carotid intima media thickness (CIMT) levels were significantly higher in PCOS patients. Although HFABP levels were higher in PCOS patients, the difference did not reach statistically significant in early age groups. After adjustment for age and body mass index, HFABP level was positive correlated with hsCRP, free testosterone levels, CIMT and HOMA-IR. Heart type free fatty acid binding protein appeared to have an important role in metabolic response and subsequent development of atherosclerosis in insulin resistant, hyperandrogenemic PCOS patients.

Cardiovascular Stress Reactivity and Carotid Intima-Media Thickness: The Buffering Role of Slow-Wave Sleep.

PubMed

Brindle, Ryan C; Duggan, Katherine A; Cribbet, Matthew R; Kline, Christopher E; Krafty, Robert T; Thayer, Julian F; Mulukutla, Suresh R; Hall, Martica H

2018-04-01

Exaggerated cardiovascular reactivity to acute psychological stress has been associated with increased carotid intima-media thickness (IMT). However, interstudy variability in this relationship suggests the presence of moderating factors. The current study aimed to test the hypothesis that poor nocturnal sleep, defined as short total sleep time or low slow-wave sleep, would moderate the relationship between cardiovascular reactivity and IMT. Participants (N = 99, 65.7% female, age = 59.3 ± 9.3 years) completed a two-night laboratory sleep study and cardiovascular examination where sleep and IMT were measured. The multisource interference task was used to induce acute psychological stress, while systolic and diastolic blood pressure and heart rate were monitored. Moderation was tested using the PROCESS framework in SPSS. Slow-wave sleep significantly moderated the relationship between all cardiovascular stress reactivity variables and IMT (all pinteraction ≤ .048, all ΔRinteraction ≥ .027). Greater stress reactivity was associated with higher IMT values in the low slow-wave sleep group and lower IMT values in the high slow-wave sleep group. No moderating effects of total sleep time were observed. The results provide evidence that nocturnal slow-wave sleep moderates the relationship between cardiovascular stress reactivity and IMT and may buffer the effect of daytime stress-related disease processes.

Residential exposure to urban traffic is associated with increased carotid intima-media thickness in children.

PubMed

Armijos, Rodrigo X; Weigel, M Margaret; Myers, Orrin B; Li, Wen-Whai; Racines, Marcia; Berwick, Marianne

2015-01-01

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure. The multivariable analyses revealed that children residing <100 meters from the nearest heavily trafficked road had cIMT mean and maximum measurements that were increased by 15% and 11% compared to those living ≥ 200 meters away (P = 0.0001). Similar increases in cIMT were identified for children in the highest versus lowest DWTD tertile. Children who resided 100-199 meters from traffic or in the middle DWTD tertile also exhibited increased cIMT but these differences were not statistically significant. No statistically significant differences were identified between residential distance to traffic or DWTD and systemic inflammation indicators (CRP, IL-6). The study results suggest that exposure to urban traffic promotes arterial remodeling in children. This finding is important since even small increases in cIMT over time can potentially lead to earlier progression to atherosclerosis. It is also important because traffic-related pollution is potentially modifiable.

Increased risk of QT prolongation associated with atherosclerotic diseases in arseniasis-endemic area in southwestern coast of Taiwan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, C.-H.; Chen, C.-L.; Hsiao, C.K.

2009-09-15

Chronic arsenic exposure has been documented to be associated with various cardiovascular diseases. We aimed to investigate 1) the increased risk of QT prolongation in chronic arsenic exposure, and 2) the relationships of cardiac repolarization (QT interval duration) with ischemic heart disease and carotid atherosclerosis. We studied 280 men and 355 women living in the endemic area of arseniasis in southwestern Taiwan. QT intervals in electrocardiogram and carotid intima-media thickness (IMT) by ultrasonography were measured. Ischemic heart disease was diagnosed by history or abnormal electrocardiogram. Significant associations of the corrected QT interval (QTc) duration with ischemic heart disease and carotidmore » intima-medium thickness and plaque were observed after adjustment for various risk factors in the multiple linear regression analysis (all p values < 0.05). Three indices of chronic arsenic exposure were all significantly associated with the risk of QTc prolongation showing dose-response relationships (p < 0.001). Chronic arsenic exposure was dose-dependently associated with the risk of QTc prolongation. Ischemic heart disease and carotid atherosclerosis were significantly associated with QTc intervals in chronic arsenic exposure. QTc prolongation might be suggested as an early biomarker for ischemic heart disease or carotid atherosclerosis in population with previous exposure to arsenic.« less

Triactome: neuro-immune-adipose interactions. Implication in vascular biology.

PubMed

Chaldakov, George Nikov; Fiore, Marco; Ghenev, Peter I; Beltowski, Jerzy; Ranćić, Gorana; Tunçel, Neşe; Aloe, Luigi

2014-01-01

Understanding how the precise interactions of nerves, immune cells, and adipose tissue account for cardiovascular and metabolic biology is a central aim of biomedical research at present. A long standing paradigm holds that the vascular wall is composed of three concentric tissue coats (tunicae): intima, media, and adventitia. However, large- and medium-sized arteries, where usually atherosclerotic lesions develop, are consistently surrounded by periadventitial adipose tissue (PAAT), we recently designated tunica adiposa (in brief, adiposa like intima, media, and adventitia). Today, atherosclerosis is considered an immune-mediated inflammatory disease featured by endothelial dysfunction/intimal thickening, medial atrophy, and adventitial lesions associated with adipose dysfunction, whereas hypertension is characterized by hyperinnervation-associated medial thickening due to smooth muscle cell hypertrophy/hyperplasia. PAAT expansion is associated with increased infiltration of immune cells, both adipocytes and immunocytes secreting pro-inflammatory and anti-inflammatory (metabotrophic) signaling proteins collectively dubbed adipokines. However, the role of vascular nerves and their interactions with immune cells and paracrine adipose tissue is not yet evaluated in such an integrated way. The present review attempts to briefly highlight the findings in basic and translational sciences in this area focusing on neuro-immune-adipose interactions, herein referred to as triactome. Triactome-targeted pharmacology may provide a novel therapeutic approach in cardiovascular disease.

Psychosocial factors at home and at work and four-year progression in intima media thickness.

PubMed

Eller, Nanna Hurwitz; Netterstrøm, Bo

2007-01-01

This study analyzed the relationship between psychosocial factors and progression in intima media thickness (IMT). In 1998 and 2002, 95 healthy participants underwent a clinical examination, including ultrasound of the arteria carotis communis (ACC). IMT progression in women was 0.033 mm/year (SD=0.033) and in men 0.048 mm/year (SD=0.033). For cohabiting women as opposed to single women, the means for total IMT progression over the 4 years were, respectively, 0.137 (SE=0.019) and 0.016 (SE=0.048) mm. For women with above average as opposed to below average mean scores of effort, IMT progression were 0.149 (SE=0.026) and 0.098 (SE=0.024) mm, respectively. For men without children as opposed to men with children, mean scores for IMT progression were 0.231 (SE=0.029) and 0.137 (SE=0.028) mm, respectively. For men above average as opposed to those below average, scores of effort-reward imbalance IMT progression were 0.216 (SE=0.030) and 0.155 (SE=0.027) mm, respectively. Adjustment for confounders did not change the results significantly. We found that psychosocial factors were independent significant predictors of IMT progression. The associations were different between the genders.

Sedentary behaviour patterns and carotid intima-media thickness in Spanish healthy adult population.

PubMed

García-Hermoso, Antonio; Martínez-Vizcaíno, Vicente; Recio-Rodríguez, José Ignacio; Sánchez-López, Mairena; Gómez-Marcos, Manuel Ángel; García-Ortiz, Luis

2015-04-01

The aim of this study was to analyze the association between sedentary behaviour, as assessed by an accelerometer, and mean carotid intima-media thickness (IMT). The study included 263 healthy subjects belonging to the EVIDENT study (59.3% women). Carotid IMT was measured by carotid ultrasonography. Sedentary behaviour was measured objectively over 7 days using ActiGraph accelerometers. Thresholds of 10 consecutive minutes were used to establish sedentary bouts, and assess the number (n/day), and length ≥10 min (min/day). Total sedentary time and sedentary time in bouts ≥10 min was higher in participants with a larger mean carotid IMT (>P75). Otherwise, this sedentary time in bouts ≥10 min parameter was weakly associated with augmented carotid IMT injury in the logistic regression model. Total sedentary time and sedentary time in bouts ≥10 min, as assessed by accelerometer, was positively but weakly associated with carotid IMT. Equally, this sedentary time in bouts ≥10 min was associated with carotid injury, but disappears after adjusting for potential confounders. These findings support that reducing sedentary time and increasing breaks in bouts of sedentary time might represent a useful additional strategy in the cardiovascular disease prevention. Clinical Trials.gov Identifier: NCT01083082. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Atheroprotective Properties of Serum IGF-1 in the Carotid and Coronary Territories and Beneficial Role on the Physical Fitness of the Oldest Old.

PubMed

Córdova, Claudio; Boullosa, Daniel A; Custódio, Misael R M; Quaglia, Luiz A; Santos, Simone N; Freitas, Wladimir M; Sposito, Andrei C; Nóbrega, Otávio T

2016-10-01

Our aim was to investigate whether physiological levels of soluble insulin-like growth factor-1 (IGF-1) associate with coronary and carotid atherosclerotic burden and physical fitness in the oldest old by means of a cross-sectional study including 100 community-dwelling individuals with no previous cardiovascular events. Linear correlation was found between IGF-1 and intima-media thickness, number of carotid plaques, and walking speed. Individuals in the upper IGF-1 tertile had smaller right and left intima-media thickness compared with the intermediate and lower tertiles, along with reduced atherosclerotic plaques. Also, walking speed was greater in the upper IGF-1 tertile. On the other hand, a nonlinear correlation was observed between IGF-1 and coronary calcification scores, with the intermediate IGF-1 tertile associated to the lowest scores of calcification and participants with lower circulating levels of IGF-1 showing higher frequency of high-risk morphology plaques. All in all, our report supports a territory-dependent, atherorefractory phenotype in the oldest old carrying middle and/or higher serum levels of IGF-1. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chimera Analysis Supports a Predominant Role of PDGFRβ in Promoting Smooth-Muscle Cell Chemotaxis after Arterial Injury

PubMed Central

Buetow, Bernard S.; Tappan, Kristen A.; Crosby, Jeffrey R.; Seifert, Ronald A.; Bowen-Pope, Daniel F.

2003-01-01

The carotid artery shows a common response to many forms of injury, including a rapid activation of smooth muscle cell (SMC) proliferation in the media and migration of SMCs into the intima to form a neointima. Platelet-derived growth factor (PDGF) is believed to play a role in this response to injury, but it has proven difficult to distinguish whether it is stimulating cell migration or cell proliferation, and whether the action is direct or indirect. To determine this, we created chimeric mice composed of both wild-type (WT) and marked PDGF receptor β (PDGFRβ)-deficient cells, and determined the consequences of PDGFRβ expression for SMC participation in response to ligation of the left common carotid artery. The proportion of PDGFRβ−/− SMCs increased 4.5-fold in the media and decreased 1.8-fold during formation of the neointima, consistent with migration of WT SMCs out of the media and into the intima, leaving the PDGFRβ−/− cells behind. The fibrotic reaction in the adventitia, which does not involve cell migration, did not result in any change in relative abundance of WT and PDGFRβ-deficient fibroblasts. We conclude that the most significant direct role of PDGFRβ is to mediate responses that involve cell migration rather than proliferation. PMID:12937138

Treatment of androgen excess in adolescent girls: ethinylestradiol-cyproteroneacetate versus low-dose pioglitazone-flutamide-metformin.

PubMed

Ibáñez, Lourdes; Diaz, Marta; Sebastiani, Giorgia; Sánchez-Infantes, David; Salvador, Cristina; Lopez-Bermejo, Abel; de Zegher, Francis

2011-11-01

The aim was to perform a first comparison between the effects of a classic therapy and those of a novel treatment for androgen excess in adolescent girls. We conducted a randomized, open-labeled trial at a university hospital. Thirty-four adolescents with hyperinsulinemic androgen excess and without risk of pregnancy participated in the study. Ethinyl estradiol-cyproterone acetate (EE-CA) vs. a low-dose combination of pioglitazone, flutamide, and metformin (PioFluMet) was administered for 6 months. We assessed hirsutism and acne scores; androgen excess; fasting insulin, lipid profile, C-reactive protein, high molecular-weight adiponectin, leptin, follistatin; carotid intima-media thickness; body composition (absorptiometry); and abdominal fat partitioning (magnetic resonance imaging). EE-CA and PioFluMet attenuated the androgen excess comparably but had divergent effects on fasting insulinemia; on circulating cholesterol, triglycerides, C-reactive protein, high molecular-weight adiponectin, leptin, and follistatin; on carotid intima-media thickness; on lean mass; and on abdominal, visceral, and hepatic fat, with all these divergences pointing to a healthier condition on low-dose PioFluMet. Low-dose PioFluMet compared favorably to EE-CA in adolescents with androgen excess and without pregnancy risk. The efficacy and safety of low-dose PioFluMet remain to be studied over a longer term and in larger cohorts.

Effects of valproate on the carotid artery intima-media thickness in epileptics.

PubMed

Luo, Xinming; Zhang, Ming; Deng, Liying; Zhao, Jing

2015-01-01

The objective was to explore the effects of valproate (VPA) on the carotid artery intima-media thickness (CA-IMT) in epileptics. A total of 30 epileptic patients treated with VPA was included as disease group, while 33 healthy people who matched general basic demographic details were the control group. The IMTs of the left and right carotids of the both groups were measured, and the average CA-IMT was calculated. The IMT-related risk factors were acquired for the univariate and multivariate analysis. The bilateral carotid and average CA-IMTs of the disease group were significantly higher than the control group (P < 0.001). The multivariant gradual regressive analysis screened out two CA-IMT-related factors, namely the disease duration and the drug administration duration were positively correlated with the average CA-IMT. The epileptic patients with disease course of more than 3 years had much higher average CA-IMT than that of the epileptics with ≤3 years disease (P < 0.001). The average CA-IMT of the patients with VPA-administration duration >1 year was also higher than that of the patients with VPA-administration duration <1 year, while the difference was not statistically significant (P = 0.196). The average CA-IMT of the epileptic patients treated with VPA was higher than that of healthy people.

A Trigger Mechanism for Volcanic Low-Frequency Seismic Events on Montserrat

NASA Astrophysics Data System (ADS)

Neuberg, J. W.; Tuffen, H.; Jolly, A.; Green, D.

2003-12-01

Seismic observations of low-frequency earthquake swarms on Montserrat point to a non-destructive, repeatable source mechanism in a confined area inside or near the conduit. While the seismic wave propagation pattern of the subsequent resonance in and around the conduit is well studied, the trigger mechanism has remained elusive. In this contribution we suggest a trigger mechanism based on new field evidence for fracture and healing of magma in volcanic conduits, together with seismic observations from Montserrat and finite element modelling of magma deformation during conduit flow. As a seismic trigger we suggest a stick-slip motion of highly-viscous magma in the glass transition, that periodically generates networks of seismogenic shear fractures a few metres in length. These fractures are rapidly filled by fine-grained material [cataclasite] that is generated by friction processes on the fracture surfaces, such as corner abrasion, and is locally redeposited by gas flowing within the fracture system. Filled fractures are then swiftly healed as reloading leads to annealing and a return to cohesive viscous deformation. Such a fast healing process, probably on the order of tens of seconds, leads to a repeatable trigger mechanism. Due to a strong lateral viscosity gradient in the conduit, highly-viscous magma near the conduit walls, which can exhibit brittle behaviour, co-exists with low-viscosity, fluid magma in the conduit centre; such that brittle failure provides the seismic trigger mechanism while the fluid part can still act as a seismic resonator.

Defining adipose tissue-derived stem cells in tissue and in culture.

PubMed

Lin, Ching-Shwun; Xin, Zhong-Cheng; Deng, Chun-Hua; Ning, Hongxiu; Lin, Guiting; Lue, Tom F

2010-06-01

Adipose tissue-derived stem cells (ADSC) are routinely isolated from the stromal vascular fraction (SVF) of homogenized adipose tissue. Similar to other types of mesenchymal stem cells (MSC), ADSC remain difficult to define due to the lack of definitive cellular markers. Still, many types of MSC, including ADSC, have been shown to reside in a perivascular location, and increasing evidence shows that both MSC and ADSC may in fact be vascular stem cells (VSC). Locally, these cells differentiate into smooth muscle and endothelial cells that are assembled into newly formed blood vessels during angiogenesis and neovasculogenesis. Additionally, MSC or ADSC can also differentiate into tissue cells such as adipocytes in the adipose tissue. Systematically, MSC or ADSC are recruited to injury sites where they participate in the repair/regeneration of the injured tissue. Due to the vasculature's dynamic capacity for growth and multipotential nature for diversification, VSC in tissue are individually at various stages and on different paths of differentiation. Therefore, when isolated and put in culture, these cells are expected to be heterogeneous in marker expression, renewal capacity, and differentiation potential. Although this heterogeneity of VSC does impose difficulties and cause confusions in basic science studies, its impact on the development of VSC as a therapeutic cell source has not been as apparent, as many preclinical and clinical trials have reported favorable outcomes. With this understanding, ADSC are generally defined as CD34+CD31- although loss of CD34 expression in culture is well documented. In adipose tissue, CD34 is localized to the intima and adventitia of blood vessels but not the media where cells expressing alpha-smooth muscle actin (SMA) exist. By excluding the intima, which contains the CD34+CD31+ endothelial cells, and the media, which contains the CD34-CD31- smooth muscle cells, it leaves the adventitia as the only possible location for the CD34+ ADSC. In the capillary, CD34 and CD140b (a pericyte marker) are mutually exclusively expressed, thus suggesting that pericytes are not the CD34+ ADSC. Many other cellular markers for vascular cells, stem cells, and stem cell niche have also been investigated as possible ADSC markers. Particularly the best-known MSC marker STRO-1 has been found either expressed or not expressed in cultured ADSC. In the adipose tissue, STRO-1 appears to be expressed exclusively in the endothelium of certain but not all blood vessels, and thus not associated with the CD34+ ADSC. In conclusion, we believe that ADSC exist as CD34+CD31-CD104b-SMA- cells in the capillary and in the adventitia of larger vessels. In the capillary these cells coexist with pericytes and endothelial cells, both of which are possibly progenies of ADSC (or more precisely VSC). In the larger vessels, these ADSC or VSC exist as specialized fibroblasts (having stem cell properties) in the adventitia.

Headward growth of chasmata by volatile outbursts, collapse, and drainage: Evidence from ganges chaos, Mars

USGS Publications Warehouse

Rodriguez, J.A.P.; Kargel, J.; Crown, D.A.; Bleamaster, L. F.; Tanaka, K.L.; Baker, V.; Miyamoto, H.; Dohm, J.M.; Sasaki, S.; Komatsu, G.

2006-01-01

The nature and significance of collapse processes in Capri, Eos, and Ganges Chasmata remain poorly understood. Using Ganges Chasma as a type locality, these chasmata are interpreted to be the result of clustering and assimilation of multiple chaotic terrains, which primarily formed by localized depressurization-induced or thermally-triggered dissociation of buried gas clathrate hydrates and explosive eruption of gas-saturated ground water. Such crustal destabilization could have been triggered by (1) deep fracture propagation from the Martian surface, (2) magmatic intrusions and associated heating and inflation-induced terrain fracturing, and/or (3) climatic thaw and thinning/weakening of the permafrost over the clathrate and gas-rich groundwater zones. Volume increases associated with release of gases contributed to the xpulsion of groundwater and fluidized sediments at the surface, thereby carving the higher outflow channels peripheral to the chasmata and the lower outflow channel floors of the chasmata and outflow channels. Copyright 2006 by the American Geophysical Union.

S100-alarmins: potential therapeutic targets for arthritis.

PubMed

Austermann, Judith; Zenker, Stefanie; Roth, Johannes

2017-07-01

In arthritis, inflammatory processes are triggered by numerous factors that are released from joint tissues, promoting joint destruction and pathological progression. During inflammation, a novel family of pro-inflammatory molecules called alarmins is released, amplifying inflammation and joint damage. Areas covered: With regard to the role of the alarmins S100A8 and S100A9 in the pathogenesis of arthritis, recent advances and the future prospects in terms of therapeutic implications are considered. Expert opinion: There is still an urgent need for novel treatment strategies addressing the local mechanisms of joint inflammation and tissue destruction, offering promising therapeutic alternatives. S100A8 and S100A9, which are the most up-regulated alarmins during arthritis, are endogenous triggers of inflammation, defining these proteins as promising targets for local suppression of arthritis. In murine models, the blockade of S100A8/S100A9 ameliorates inflammatory processes, including arthritis, and there are several lines of evidence that S100-alarmins may already be targeted in therapeutic approaches in man.

Tank binding kinase 1 is a centrosome-associated kinase necessary for microtubule dynamics and mitosis

PubMed Central

Pillai, Smitha; Nguyen, Jonathan; Johnson, Joseph; Haura, Eric; Coppola, Domenico; Chellappan, Srikumar

2015-01-01

TANK Binding Kinase 1 (TBK1) is a non-canonical IκB kinase that contributes to KRAS-driven lung cancer. Here we report that TBK1 plays essential roles in mammalian cell division. Specifically, levels of active phospho-TBK1 increase during mitosis and localize to centrosomes, mitotic spindles and midbody, and selective inhibition or silencing of TBK1 triggers defects in spindle assembly and prevents mitotic progression. TBK1 binds to the centrosomal protein CEP170 and to the mitotic apparatus protein NuMA, and both CEP170 and NuMA are TBK1 substrates. Further, TBK1 is necessary for CEP170 centrosomal localization and binding to the microtubule depolymerase Kif2b, and for NuMA binding to dynein. Finally, selective disruption of the TBK1–CEP170 complex augments microtubule stability and triggers defects in mitosis, suggesting that TBK1 functions as a mitotic kinase necessary for microtubule dynamics and mitosis. PMID:26656453

Dendritic Na+ spikes enable cortical input to drive action potential output from hippocampal CA2 pyramidal neurons

PubMed Central

Sun, Qian; Srinivas, Kalyan V; Sotayo, Alaba; Siegelbaum, Steven A

2014-01-01

Synaptic inputs from different brain areas are often targeted to distinct regions of neuronal dendritic arbors. Inputs to proximal dendrites usually produce large somatic EPSPs that efficiently trigger action potential (AP) output, whereas inputs to distal dendrites are greatly attenuated and may largely modulate AP output. In contrast to most other cortical and hippocampal neurons, hippocampal CA2 pyramidal neurons show unusually strong excitation by their distal dendritic inputs from entorhinal cortex (EC). In this study, we demonstrate that the ability of these EC inputs to drive CA2 AP output requires the firing of local dendritic Na+ spikes. Furthermore, we find that CA2 dendritic geometry contributes to the efficient coupling of dendritic Na+ spikes to AP output. These results provide a striking example of how dendritic spikes enable direct cortical inputs to overcome unfavorable distal synaptic locale to trigger axonal AP output and thereby enable efficient cortico-hippocampal information flow. DOI: http://dx.doi.org/10.7554/eLife.04551.001 PMID:25390033

Evaluating the influence of gully erosion on landslide hazard analysis triggered by heavy rainfall

NASA Astrophysics Data System (ADS)

Ruljigaljig, Tjuku; Tsai, Ching-Jun; Peng, Wen-Fei; Yu, Teng-To

2017-04-01

During the rainstorm period such as typhoon or heavy rain, the development of gully will induce a large-scale landslide. The purpose of this study is to assess and quantify the existence and development of gully for the purpose of triggering landslides by analyzing the landslides hazard. Firstly, based on multi-scale DEM data, this study uses wavelet transform to construct an automatic algorithm. The 1-meter DEM is used to evaluate the location and type of gully, and to establish an evaluation model for predicting erosion development.In this study, routes in the Chai-Yi were studied to clarify the damage potential of roadways from local gully. The local of gully is regarded as a parameter to reduce the strength parameter. The distribution of factor of safe (F.S.) is compared with the landslide inventory map. The result of this research could be used to increase the prediction accuracy of landslide hazard analysis due to heavy rainfalls.

Thermo-responsive magnetic liposomes for hyperthermia-triggered local drug delivery.

PubMed

Dai, Min; Wu, Cong; Fang, Hong-Ming; Li, Li; Yan, Jia-Bao; Zeng, Dan-Lin; Zou, Tao

2017-06-01

We prepared and characterised thermo-responsive magnetic liposomes, which were designed to combine features of magnetic targeting and thermo-responsive control release for hyperthermia-triggered local drug delivery. The particle size and zeta-potential of the thermo-responsive magnetic ammonium bicarbonate (MagABC) liposomes were about 210 nm and -14 mV, respectively. The MagABC liposomes showed encapsulation efficiencies of about 15% and 82% for magnetic nanoparticles (mean crystallite size 12 nm) and doxorubicin (DOX), respectively. The morphology of the MagABC liposomes was visualised using transmission electron microscope (TEM). The MagABC liposomes showed desired thermo-responsive release. The MagABC liposomes, when physically targeted to tumour cells in culture by a permanent magnetic field yielded a substantial increase in intracellular accumulation of DOX as compared to non-magnetic ammonium bicarbonate (ABC) liposomes. This resulted in a parallel increase in cytotoxicity for DOX loaded MagABC liposomes over DOX loaded ABC liposomes in tumour cells.

Subduction zone earthquake probably triggered submarine hydrocarbon seepage offshore Pakistan

NASA Astrophysics Data System (ADS)

Fischer, David; José M., Mogollón; Michael, Strasser; Thomas, Pape; Gerhard, Bohrmann; Noemi, Fekete; Volkhard, Spiess; Sabine, Kasten

2014-05-01

Seepage of methane-dominated hydrocarbons is heterogeneous in space and time, and trigger mechanisms of episodic seep events are not well constrained. It is generally found that free hydrocarbon gas entering the local gas hydrate stability field in marine sediments is sequestered in gas hydrates. In this manner, gas hydrates can act as a buffer for carbon transport from the sediment into the ocean. However, the efficiency of gas hydrate-bearing sediments for retaining hydrocarbons may be corrupted: Hypothesized mechanisms include critical gas/fluid pressures beneath gas hydrate-bearing sediments, implying that these are susceptible to mechanical failure and subsequent gas release. Although gas hydrates often occur in seismically active regions, e.g., subduction zones, the role of earthquakes as potential triggers of hydrocarbon transport through gas hydrate-bearing sediments has hardly been explored. Based on a recent publication (Fischer et al., 2013), we present geochemical and transport/reaction-modelling data suggesting a substantial increase in upward gas flux and hydrocarbon emission into the water column following a major earthquake that occurred near the study sites in 1945. Calculating the formation time of authigenic barite enrichments identified in two sediment cores obtained from an anticlinal structure called "Nascent Ridge", we find they formed 38-91 years before sampling, which corresponds well to the time elapsed since the earthquake (62 years). Furthermore, applying a numerical model, we show that the local sulfate/methane transition zone shifted upward by several meters due to the increased methane flux and simulated sulfate profiles very closely match measured ones in a comparable time frame of 50-70 years. We thus propose a causal relation between the earthquake and the amplified gas flux and present reflection seismic data supporting our hypothesis that co-seismic ground shaking induced mechanical fracturing of gas hydrate-bearing sediments creating pathways for free gas to migrate from a shallow reservoir within the gas hydrate stability zone into the water column. Our results imply that free hydrocarbon gas trapped beneath a local gas hydrate seal was mobilized through earthquake-induced mechanical failure and in that way circumvented carbon sequestration within the sediment. These findings lead to conclude that hydrocarbon seepage triggered by earthquakes can play a role for carbon budgets at other seismically active continental margins. The newly identified process presented in our study is conceivable to help interpret data from similar sites. Reference: Fischer, D., Mogollon, J.M., Strasser, M., Pape, T., Bohrmann, G., Fekete, N., Spieß, V. and Kasten, S., 2013. Subduction zone earthquake as potential trigger of submarine hydrocarbon seepage. Nature Geoscience 6: 647-651.

Syn-eruptive, soft-sediment deformation of dilute pyroclastic density current deposits: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves

NASA Astrophysics Data System (ADS)

Douillet, G. A.; Taisne, B.; Tsang-Hin-Sun, È.; Müller, S. K.; Kueppers, U.; Dingwell, D. B.

2014-12-01

Soft-sediment deformation produces intriguing sedimentary structures and can occur in diverse environments and from a variety of triggers. From the observation of such structures and their interpretation in terms of trigger mechanisms, valuable information can be extracted about former conditions. Here we document examples of syn-eruptive deformation in dilute pyroclastic density current deposits. Outcrops from 6 different volcanoes have been compiled in order to provide a broad perspective on the variety of structures: Ubehebe craters (USA), Tungurahua (Ecuador), Soufrière Hills (Montserrat), Laacher See (Germany), Tower Hill and Purrumbete lake (both Australia). Isolated slumps as well as sinking pseudonodules are driven by their excess weight and occur after deposition but penecontemporaneous to the eruption. Isolated, cm-scale, overturned beds with vortex forms have been interpreted to be the signature of shear instabilities occurring at the boundary of two granular media. They may represent the frozen record of granular, pseudo Kelvin-Helmholtz instabilities. Their recognition can be a diagnostic for flows with a granular basal boundary layer. The occurrence of degassing pipes together with basal intrusive dikes suggest fluidization during flow stages, and can facilitate the development of Kelvin-Helmholtz structures. The occurrence at the base of flow units of injection dikes in some outcrops compared with suction-driven local uplifts in others indicates the role of dynamic pore pressure. Variations of the latter are possibly related to local changes between depletive and accumulative dynamics of flows. Ballistic impacts can trigger unconventional sags producing local displacement or liquefaction. Based on the deformation depth, these can yield precise insights into depositional unit boundaries. Such impact structures may also be at the origin of some of the steep truncation planes visible at the base of the so-called "chute and pool" structures. Finally, the passage of shock waves emanating from the vent may be preserved in the form of trains of isolated, fine-grained overturned beds which may disturb the surface bedding without occurrence of a sedimentation phase in the vicinity of a vent. Dilute pyroclastic density currents occur contemporaneously with seismogenic volcanic explosions. They are often deposited on steep slopes and can incorporate large amounts of water and gas in the sediment. They can experience extremely high sedimentation rates and may flow at the border between traction, granular and fluid-escape boundary zones. These are just some of the many possible triggers acting in a single environment, and reveal the potential for insights into the eruptive mechanisms of dilute pyroclastic density currents.

Airborne signals from Trichoderma fungi stimulate iron uptake responses in roots resulting in priming of jasmonic acid-dependent defences in shoots of Arabidopsis thaliana and Solanum lycopersicum.

PubMed

Martínez-Medina, Ainhoa; Van Wees, Saskia C M; Pieterse, Corné M J

2017-11-01

Root colonization by Trichoderma fungi can trigger induced systemic resistance (ISR). In Arabidopsis, Trichoderma-ISR relies on the transcription factor MYB72, which plays a dual role in the onset of ISR and the activation of Fe uptake responses. Volatile compounds (VCs) from rhizobacteria are important elicitors of MYB72 in Arabidopsis roots. Here, we investigated the mode of action of VCs from Trichoderma fungi in the onset of ISR and Fe uptake responses. VCs from Trichoderma asperellum and Trichoderma harzianum were applied in an in vitro split-plate system with Arabidopsis or tomato seedlings. Locally, Trichoderma-VCs triggered MYB72 expression and molecular, physiological and morphological Fe uptake mechanisms in Arabidopsis roots. In leaves, Trichoderma-VCs primed jasmonic acid-dependent defences, leading to an enhanced resistance against Botrytis cinerea. By using Arabidopsis micrografts of VCs-exposed rootstocks and non-exposed scions, we demonstrated that perception of Trichoderma-VCs by the roots leads to a systemic signal that primes shoots for enhanced defences. Trichoderma-VCs also elicited Fe deficiency responses and shoot immunity in tomato, suggesting that this phenomenon is expressed in different plant species. Our results indicate that Trichoderma-VCs trigger locally a readjustment of Fe homeostasis in roots, which links to systemic elicitation of ISR by priming of jasmonic acid-dependent defences. © 2017 John Wiley & Sons Ltd.

Effects of Spatial Variability of Soil Properties on the Triggering of Rainfall-Induced Shallow Landslides

NASA Astrophysics Data System (ADS)

Fan, Linfeng; Lehmann, Peter; Or, Dani

2015-04-01

Naturally-occurring spatial variations in soil properties (e.g., soil depth, moisture, and texture) affect key hydrological processes and potentially the mechanical response of soil to hydromechanical loading (relative to the commonly-assumed uniform soil mantle). We quantified the effects of soil spatial variability on the triggering of rainfall-induced shallow landslides at the hillslope- and catchment-scales, using a physically-based landslide triggering model that considers interacting soil columns with mechanical strength thresholds (represented by the Fiber Bundle Model). The spatial variations in soil properties are represented as Gaussian random distributions and the level of variation is characterized by the coefficient of variation and correlation lengths of soil properties (i.e., soil depth, soil texture and initial water content in this study). The impacts of these spatial variations on landslide triggering characteristics were measured by comparing the times to triggering and landslide volumes for heterogeneous soil properties and homogeneous cases. Results at hillslope scale indicate that for spatial variations of an individual property (without cross correlation), the increasing of coefficient of variation introduces weak spots where mechanical damage is accelerated and leads to earlier onset of landslide triggering and smaller volumes. Increasing spatial correlation length of soil texture and initial water content also induces early landslide triggering and small released volumes due to the transition of failure mode from brittle to ductile failure. In contrast, increasing spatial correlation length of soil depth "reduces" local steepness and postpones landslide triggering. Cross-correlated soil properties generally promote landslide initiation, but depending on the internal structure of spatial distribution of each soil property, landslide triggering may be reduced. The effects of cross-correlation between initial water content and soil texture were investigated in detail at the catchment scale by incorporating correlations of both variables with topography. Results indicate that the internal structure of the spatial distribution of each soil property together with their interplays determine the overall performance of the coupled spatial variability. This study emphasizes the importance of both the randomness and spatial structure of soil properties on landslide triggering and characteristics.

Endothelial dysfunction, vascular disease and stroke: the ARTICO study.

PubMed

Roquer, J; Segura, T; Serena, J; Castillo, J

2009-01-01

Endothelial dysfunction is a fundamental step in the atherosclerotic disease process. Its presence is a risk factor for the development of clinical events, and may represent a marker of atherothrombotic burden. Also, endothelial dysfunction contributes to enhanced plaque vulnerability, may trigger plaque rupture, and favors thrombus formation. The assessment of endothelial vasomotion is a useful marker of atherosclerotic vascular disease. There are different methods to assess endothelial function: endothelium-dependent vasodilatation brachial flow-mediated dilation, cerebrovascular reactivity to L-arginine, and the determination of some biomarkers such as microalbuminuria, platelet function, and C-reactive protein. Endothelial dysfunction has been observed in stroke patients and has been related to stroke physiopathology, stroke subtypes, clinical severity and outcome. Resting ankle-brachial index (ABI) is also considered an indicator of generalized atherosclerosis, and a low ABI is associated with an increase in stroke incidence in the elderly. Despite all these data, there are no studies analyzing the predictive value of ABI for new cardiovascular events in patients after suffering an acute ischemic stroke. ARTICO is an ongoing prospective, observational, multicenter study being performed in 50 Spanish hospitals. The aim of the ARTICO study is to evaluate the prognostic value of a pathological ABI (

Poly(ADP-ribose) polymerase inhibition combined with irradiation: A dual treatment concept to prevent neointimal hyperplasia after endarterectomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beller, Carsten J.; Kosse, Jens; Radovits, Tamas

2006-11-01

Purpose: In a rat model of endarterectomy we investigated the potential role of the peroxynitrite-poly(ADP-ribose) polymerase (PARP) pathway in neointima formation and the effects of irradiation, pharmacologic inhibition of PARP, or combined pharmacologic inhibition of PARP and irradiation on vascular remodeling. Methods and Materials: Carotid endarterectomy was performed by incision of the left carotid artery with removal of intima in Sprague-Dawley rats. Six groups were studied: sham-operated rats (n = 10), control endarterectomized rats (n = 10), or endarterectomized rats irradiated with 15 Gy (n = 10), or treated with PARP inhibitor, INO-1001 (5 mg/kg/day) (n = 10), or withmore » combined treatment with INO-1001 and irradiation with 5 Gy (n = 10) or with 15 Gy (n = 10). After 21 days, neointima formation and vascular remodeling were assessed. Results: Neointima formation after endarterectomy was inhibited by postoperative irradiation with 15 Gy and was attenuated by PARP inhibition. However, in parallel to inhibition of neointimal hyperplasia, activation of the peroxynitrite-PARP pathway in the outer vessel wall layers was triggered by postoperative irradiation. Combined pharmacologic PARP inhibition and irradiation with 15 Gy significantly reduced both neointimal hyperplasia and activation of the peroxynitrite-PARP pathway in the outer vessel wall layers. Combination of PARP inhibition and irradiation with 5 Gy was less effective than both PARP inhibition or irradiation with 15 Gy alone. Conclusions: We conclude, that combined PARP inhibition and irradiation with 15 Gy may be a new dual strategy for prevention of restenosis after surgical vessel reconstruction: combining the strong antiproliferative effect of irradiation and ameliorating irradiation-induced side effects caused by excessive PARP activation.« less

Using a national archive of patient experience narratives to promote local patient-centered quality improvement: an ethnographic process evaluation of 'accelerated' experience-based co-design.

PubMed

Locock, Louise; Robert, Glenn; Boaz, Annette; Vougioukalou, Sonia; Shuldham, Caroline; Fielden, Jonathan; Ziebland, Sue; Gager, Melanie; Tollyfield, Ruth; Pearcey, John

2014-10-01

To evaluate an accelerated form of experience-based co-design (EBCD), a type of participatory action research in which patients and staff work together to improve quality; to observe how acceleration affected the process and outcomes of the intervention. An ethnographic process evaluation of an adapted form of EBCD was conducted, including observations, interviews, questionnaires and documentary analysis. Whilst retaining all components of EBCD, the adapted approach replaced local patient interviews with secondary analysis of a national archive of patient experience narratives to create national trigger films; shortened the timeframe; and employed local improvement facilitators. It was tested in intensive care and lung cancer in two English National Health Service (NHS) hospitals. A total of 96 clinical staff (primarily nursing and medical), and 63 patients and family members participated in co-design activities. The accelerated approach proved acceptable to staff and patients; using films of national rather than local narratives did not adversely affect local NHS staff engagement, and may have made the process less threatening or challenging. Local patients felt the national films generally reflected important themes although a minority felt they were more negative than their own experience. However, they served their purpose of 'triggering' discussion between patients and staff, and the resulting 48 co-design (improvement) activities across the four pathways were similar to those in EBCD, but achieved more quickly and at lower cost. Accelerated EBCD offers a rigorous and relatively cost-effective patient-centered quality improvement approach. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Detection of artery interfaces: a real-time system and its clinical applications

NASA Astrophysics Data System (ADS)

Faita, Francesco; Gemignani, Vincenzo; Bianchini, Elisabetta; Giannarelli, Chiara; Ghiadoni, Lorenzo; Demi, Marcello

2008-03-01

Analyzing the artery mechanics is a crucial issue because of its close relationship with several cardiovascular risk factors, such as hypertension and diabetes. Moreover, most of the work can be carried out by analyzing image sequences obtained with ultrasounds, that is with a non-invasive technique which allows a real-time visualization of the observed structures. For this reason, therefore, an accurate temporal localization of the main vessel interfaces becomes a central task for which the manual approach should be avoided since such a method is rather unreliable and time consuming. Real-time automatic systems are advantageously used to automatically locate the arterial interfaces. The automatic measurement reduces the inter/intra-observer variability with respect to the manual measurement which unavoidably depends on the experience of the operator. The real-time visual feedback, moreover, guides physicians when looking for the best position of the ultrasound probe, thus increasing the global robustness of the system. The automatic system which we developed is a stand-alone video processing system which acquires the analog video signal from the ultrasound equipment, performs all the measurements and shows the results in real-time. The localization algorithm of the artery tunics is based on a new mathematical operator (the first order absolute moment) and on a pattern recognition approach. Various clinical applications have been developed on board and validated through a comparison with gold-standard techniques: the assessment of intima-media thickness, the arterial distension, the flow-mediated dilation and the pulse wave velocity. With this paper, the results obtained on clinical trials are presented.

Modeling plaque fissuring and dissection during balloon angioplasty intervention.

PubMed

Gasser, T Christian; Holzapfel, Gerhard A

2007-05-01

Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

Mucin-mediated nanocarrier disassembly for triggered uptake of oligonucleotides as a delivery strategy for the potential treatment of mucosal tumours

NASA Astrophysics Data System (ADS)

Martirosyan, A.; Olesen, M. J.; Fenton, R. A.; Kjems, J.; Howard, K. A.

2016-06-01

This work demonstrates gastric mucin-triggered nanocarrier disassembly for release of antisense oligonucleotides and consequent unassisted cellular entry as a novel oral delivery strategy. A fluorescence activation-based reporter system was used to investigate the interaction and mucin-mediated disassembly of chitosan-based nanocarriers containing a 13-mer DNA oligonucleotide with a flanked locked RNA nucleic acid gapmer design. Gastric mucins were shown to trigger gapmer release from nanocarriers that was dependent on the interaction time, mucin concentration and N : P ratio with a maximal release at N : P 10. In contrast to siRNA, naked gapmers exhibited uptake into mucus producing HT-MTX mono-cultures and HT-MTX co-cultured with the carcinoma epithelial cell line Caco-2. Importantly, in vivo gapmer uptake was observed in epithelial tissue 30 min post-injection in murine intestinal loops. The findings present a mucosal design-based system tailored for local delivery of oligonucleotides that may maximize the effectiveness of gene silencing therapeutics within tumours at mucosal sites.This work demonstrates gastric mucin-triggered nanocarrier disassembly for release of antisense oligonucleotides and consequent unassisted cellular entry as a novel oral delivery strategy. A fluorescence activation-based reporter system was used to investigate the interaction and mucin-mediated disassembly of chitosan-based nanocarriers containing a 13-mer DNA oligonucleotide with a flanked locked RNA nucleic acid gapmer design. Gastric mucins were shown to trigger gapmer release from nanocarriers that was dependent on the interaction time, mucin concentration and N : P ratio with a maximal release at N : P 10. In contrast to siRNA, naked gapmers exhibited uptake into mucus producing HT-MTX mono-cultures and HT-MTX co-cultured with the carcinoma epithelial cell line Caco-2. Importantly, in vivo gapmer uptake was observed in epithelial tissue 30 min post-injection in murine intestinal loops. The findings present a mucosal design-based system tailored for local delivery of oligonucleotides that may maximize the effectiveness of gene silencing therapeutics within tumours at mucosal sites. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07206a

Evidences of landslide earthquake triggering due to self-excitation process

NASA Astrophysics Data System (ADS)

Bozzano, F.; Lenti, L.; Martino, Salvatore; Paciello, A.; Scarascia Mugnozza, G.

2011-06-01

The basin-like setting of stiff bedrock combined with pre-existing landslide masses can contribute to seismic amplifications in a wide frequency range (0-10 Hz) and induce a self-excitation process responsible for earthquake-triggered landsliding. Here, the self-excitation process is proposed to justify the far-field seismic trigger of the Cerda landslide (Sicily, Italy) which was reactivated by the 6th September 2002 Palermo earthquake ( M s = 5.4), about 50 km far from the epicentre. The landslide caused damage to farm houses, roads and aqueducts, close to the village of Cerda, and involved about 40 × 106 m3 of clay shales; the first ground cracks due to the landslide movement formed about 30 min after the main shock. A stress-strain dynamic numerical modelling, performed by FDM code FLAC 5.0, supports the notion that the combination of local geological setting and earthquake frequency content played a fundamental role in the landslide reactivation. Since accelerometric records of the triggering event are not available, dynamic equivalent inputs have been used for the numerical modelling. These inputs can be regarded as representative for the local ground shaking, having a PGA value up to 0.2 m/s2, which is the maximum expected in 475 years, according to the Italian seismic hazard maps. A 2D numerical modelling of the seismic wave propagation in the Cerda landslide area was also performed; it pointed out amplification effects due to both the structural setting of the stiff bedrock (at about 1 Hz) and the pre-existing landslide mass (in the range 3-6 Hz). The frequency peaks of the resulting amplification functions ( A( f)) fit well the H/ V spectral ratios from ambient noise and the H/ H spectral ratios to a reference station from earthquake records, obtained by in situ velocimetric measurements. Moreover, the Fourier spectra of earthquake accelerometric records, whose source and magnitude are consistent with the triggering event, show a main peak at about 1 Hz. This frequency value well fits the one amplified by the geological setting of the bedrock in correspondence with the landslide area, which is constituted of marly limestones and characterised by a basin-like geometry.

Incentives for Reporting Infectious Disease Outbreaks

ERIC Educational Resources Information Center

Malani, Anup; Laxminarayan, Ramanan

2011-01-01

The global spread of diseases such as swine flu and SARS highlights the difficult decision governments face when presented with evidence of a local outbreak. Reporting the outbreak may bring medical assistance but is also likely to trigger trade sanctions by countries hoping to contain the disease. Suppressing the information may avoid trade…

Changes in blood flow and cellular metabolism at a myofascial trigger point with trigger point release (ischemic compression): a proof-of-principle pilot study

PubMed Central

Moraska, Albert F.; Hickner, Robert C.; Kohrt, Wendy M.; Brewer, Alan

2012-01-01

Objective To demonstrate proof-of-principle measurement for physiological change within an active myofascial trigger point (MTrP) undergoing trigger point release (ischemic compression). Design Interstitial fluid was sampled continuously at a trigger point before and after intervention. Setting A biomedical research clinic at a university hospital. Participants Two subjects from a pain clinic presenting with chronic headache pain. Interventions A single microdialysis catheter was inserted into an active MTrP of the upper trapezius to allow for continuous sampling of interstitial fluid before and after application of trigger point therapy by a massage therapist. Main Outcome Measures Procedural success, pain tolerance, feasibility of intervention during sample collection, determination of physiologically relevant values for local blood flow, as well as glucose and lactate concentrations. Results Both patients tolerated the microdialysis probe insertion into the MTrP and treatment intervention without complication. Glucose and lactate concentrations were measured in the physiological range. Following intervention, a sustained increase in lactate was noted for both subjects. Conclusions Identifying physiological constituents of MTrP’s following intervention is an important step toward understanding pathophysiology and resolution of myofascial pain. The present study forwards that aim by showing proof-of-concept for collection of interstitial fluid from an MTrP before and after intervention can be accomplished using microdialysis, thus providing methodological insight toward treatment mechanism and pain resolution. Of the biomarkers measured in this study, lactate may be the most relevant for detection and treatment of abnormalities in the MTrP. PMID:22975226

Probing the Cosmic Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

NASA Technical Reports Server (NTRS)

Lien, Amy; Sakamoto, Takanori; Gehrels, Neil; Palmer, David M.; Barthelmy, Scott D.; Graziani, Carlo; Cannizzo, John K.

2013-01-01

The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously own GRB instruments, Swift has over 500 trigger criteria based on photon count rate and additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we develop a program that is capable of simulating all the rate trigger criteria and mimicking the image threshold. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection rate of dim bursts. As a result, our simulations suggest bursts need to be dimmer than previously expected to avoid over-producing the number of detections and to match with Swift observations. Moreover, our results indicate that these dim bursts are more likely to be high redshift events than low-luminosity GRBs. This would imply an even higher cosmic GRB rate at large redshifts than previous expectations based on star-formation rate measurements, unless other factors, such as the luminosity evolution, are taken into account. The GRB rate from our best result gives a total number of 4568 +825 -1429 GRBs per year that are beamed toward us in the whole universe.

On near-source earthquake triggering

USGS Publications Warehouse

Parsons, T.; Velasco, A.A.

2009-01-01

When one earthquake triggers others nearby, what connects them? Two processes are observed: static stress change from fault offset and dynamic stress changes from passing seismic waves. In the near-source region (r ??? 50 km for M ??? 5 sources) both processes may be operating, and since both mechanisms are expected to raise earthquake rates, it is difficult to isolate them. We thus compare explosions with earthquakes because only earthquakes cause significant static stress changes. We find that large explosions at the Nevada Test Site do not trigger earthquakes at rates comparable to similar magnitude earthquakes. Surface waves are associated with regional and long-range dynamic triggering, but we note that surface waves with low enough frequency to penetrate to depths where most aftershocks of the 1992 M = 5.7 Little Skull Mountain main shock occurred (???12 km) would not have developed significant amplitude within a 50-km radius. We therefore focus on the best candidate phases to cause local dynamic triggering, direct waves that pass through observed near-source aftershock clusters. We examine these phases, which arrived at the nearest (200-270 km) broadband station before the surface wave train and could thus be isolated for study. Direct comparison of spectral amplitudes of presurface wave arrivals shows that M ??? 5 explosions and earthquakes deliver the same peak dynamic stresses into the near-source crust. We conclude that a static stress change model can readily explain observed aftershock patterns, whereas it is difficult to attribute near-source triggering to a dynamic process because of the dearth of aftershocks near large explosions.

High-Energy Particle Showers Observed at Ground Level in Coincidence with Downward Lightning Leaders at the Telescope Array Observatory

NASA Astrophysics Data System (ADS)

Belz, John; Abbasi, Rasha; Le Von, Ryan; Krehbiel, Paul; Remington, Jackson; Rison, William

Terrestrial Gamma Ray Flashes (TGFs) detected by satellite observations have been shown to be generated by upward propagating negative leaders at altitudes of about 10 to 12 km above Mean Sea Level (MSL), and have durations ranging between a few hundred microseconds and a few milliseconds. The Telescope Array Cosmic Ray observatory, designed to observe air showers induced by ultra high energy cosmic rays, includes a surface scintillator detector (SD) covering approximately 700 square kilometers on a 1.2 km grid. Following the observation of anomalous SD triggers correlated with local lightning activity, a Lightning Mapping Array (LMA) and slow electric field antenna were installed at the TA site in order to characterize the lightning associated with these anomalous triggers. In this talk, we present evidence that the anomalous triggers are produced during the initial breakdown phase of fast, downward propagating, negative leaders above the detectors which produced the triggers. The durations of the high energy radiation are a few hundred microseconds, similar to satellite observations of TGFs. The triggers were produced within a few hundred microseconds of the initiation of the leaders, when the leaders were at an altitude of about 3 to 4 km MSL. The TA scintillation detectors are not optimized for gamma ray detection, however we present the results of simulations demonstrating that the fluxes observed are consistent with this picture. We conclude that the anomalous triggers observed by TA are clearly due to high energy radiation produced by the fast downward propagating negative leaders, and are probably downward-directed TGFs.

Involvement of the Electrophilic Isothiocyanate Sulforaphane in Arabidopsis Local Defense Responses1

PubMed Central

Andersson, Mats X.; Nilsson, Anders K.; Johansson, Oskar N.; Boztaş, Gülin; Adolfsson, Lisa E.; Pinosa, Francesco; Petit, Christel Garcia; Aronsson, Henrik; Mackey, David; Tör, Mahmut; Hamberg, Mats; Ellerström, Mats

2015-01-01

Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue. PMID:25371552

Activation of signaling pathways following localized delivery of systemically administered neurotrophic factors across the blood-brain barrier using focused ultrasound and microbubbles

NASA Astrophysics Data System (ADS)

Baseri, Babak; Choi, James J.; Deffieux, Thomas; Samiotaki, Gesthimani; Tung, Yao-Sheng; Olumolade, Oluyemi; Small, Scott A.; Morrison, Barclay, III; Konofagou, Elisa E.

2012-04-01

The brain-derived neurotrophic factor (BDNF) has been shown to have broad neuroprotective effects in addition to its therapeutic role in neurodegenerative disease. In this study, the efficacy of delivering exogenous BDNF to the left hippocampus is demonstrated in wild-type mice (n = 7) through the noninvasively disrupted blood-brain barrier (BBB) using focused ultrasound (FUS). The BDNF bioactivity was found to be preserved following delivery as assessed quantitatively by immunohistochemical detection of the pTrkB receptor and activated pAkt, pMAPK, and pCREB in the hippocampal neurons. It was therefore shown for the first time that systemically administered neurotrophic factors can cross the noninvasively disrupted BBB and trigger neuronal downstream signaling effects in a highly localized region in the brain. This is the first time that the administered molecule is tracked through the BBB and localized in the neuron triggering molecular effects. Additional preliminary findings are shown in wild-type mice with two additional neurotrophic factors such as the glia-derived neurotrophic factor (n = 12) and neurturin (n = 2). This further demonstrates the impact of FUS for the early treatment of CNS diseases at the cellular and molecular level and strengthens its premise for FUS-assisted drug delivery and efficacy.

A Genetically Engineered Thermally Responsive Sustained Release Curcumin Depot to Treat Neuroinflammation

PubMed Central

Sinclair, S. Michael; Bhattacharyya, Jayanta; McDaniel, Jonathan R.; Gooden, David M.; Gopalaswamy, Ramesh; Chilkoti, Ashutosh; Setton, Lori A.

2014-01-01

Radiculopathy, a painful neuroinflammation that can accompany intervertebral disc herniation, is associated with locally increased levels of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). Systemic administration of TNF antagonists for radiculopathy in the clinic has shown mixed results, and there is growing interest in the local delivery of anti-inflammatory drugs to treat this pathology as well as similar inflammatory events of peripheral nerve injury. Curcumin, a known antagonist of TNFα in multiple cell types and tissues, was chemically modified and conjugated to a thermally responsive elastin-like polypeptide (ELP) to create an injectable depot for sustained, local delivery of curcumin to treat neuroinflammation. ELPs are biopolymers capable of thermally-triggered in situ depot formation that have been successfully employed as drug carriers and biomaterials in several applications. ELP-curcumin conjugates were shown to display high drug loading, rapidly release curcumin in vitro via degradable carbamate bonds, and retain in vitro bioactivity against TNFα-induced cytotoxicity and monocyte activation with IC50 only two-fold higher than curcumin. When injected proximal to the sciatic nerve in mice via intramuscular (i.m.) injection, ELP-curcumin conjugates underwent a thermally triggered soluble-insoluble phase transition, leading to in situ formation of a depot that released curcumin over 4 days post-injection and decreased plasma AUC 7-fold. PMID:23830979

Carotid Intima-Media Thickness and Plasma Asymmetric Dimethylarginine in Mexican Children Exposed to Inorganic Arsenic

PubMed Central

Osorio-Yáñez, Citlalli; Ayllon-Vergara, Julio C.; Aguilar-Madrid, Guadalupe; Arreola-Mendoza, Laura; Hernández-Castellanos, Erika; Barrera-Hernández, Angel; De Vizcaya-Ruiz, Andrea

2013-01-01

Background: Arsenic exposure is a risk factor for atherosclerosis in adults, but there is little information on arsenic and early risk biomarkers for atherosclerosis in children. Carotid intima-media thickness (cIMT) is an indicator of subclinical atherosclerotic burden that has been associated with plasma asymmetric dimethylarginine (ADMA), a predictor of cardiovascular disease risk. Objectives: The aim of this study was to investigate associations of arsenic exposure with cIMT, ADMA, and endothelial adhesion molecules [soluble intercellular cell adhesion molecule-1 (sICAM-1); soluble vascular cell adhesion molecule-1 (sVCAM-1)] in children who had been exposed to environmental inorganic arsenic (iAs). Methods: We conducted a cross-sectional study in 199 children 3–14 years of age who were residents of Zimapan, México. We evaluated cIMT using ultrasonography, and plasma lipid profiles by standard methods. We analyzed ADMA, sICAM-1, and sVCAM-1 by ELISA, and measured the concentrations of total speciated arsenic (tAs) in urine using hydride generation cryotrapping atomic absorption spectrometry. Results: In the multiple linear regression model for cIMT, tAs categories were positively associated with cIMT increase. The estimated cIMT diameter was greater in 35- to 70-ng/mL and > 70-ng/mL groups (0.035 mm and 0.058 mm per 1-ng/mL increase in urinary tAs, respectively), compared with the < 35-ng/mL group. In addition to tAs level, plasma ADMA was a significant predictor of cIMT. In the adjusted regression model, cIMT, percent iAs, and plasma sVCAM-1 were significant predictors of ADMA levels (e.g., 0.419-μmol/L increase in ADMA per 1-mm increase in cIMT). Conclusions: Arsenic exposure and plasma ADMA levels were positively associated with cIMT in a population of Mexican children with environmental arsenic exposure through drinking water. Citation: Osorio-Yáñez C, Ayllon-Vergara JC, Aguilar-Madrid G, Arreola-Mendoza L, Hernández-Castellanos E, Barrera-Hernández A, De Vizcaya-Ruíz A, Del Razo LM. 2013. Carotid intima-media thickness and plasma asymmetric dimethylarginine in Mexican children exposed to inorganic arsenic. Environ Health Perspect 121:1090–1096; http://dx.doi.org/10.1289/ehp.1205994 PMID:23757599

Effect of olive and sunflower oils on low density lipoprotein level, composition, size, oxidation and interaction with arterial proteoglycans.

PubMed

Carmena, R; Ascaso, J F; Camejo, G; Varela, G; Hurt-Camejo, E; Ordovas, J M; Martinez-Valls, J; Bergstöm, M; Wallin, B

1996-09-06

The atherogenicity of low density lipoproteins (LDL) may be modulated by its serum levels, structure and affinity for components of the intima, all properties that can be altered by diet. Linoleic acid-rich diets (n-G, 18:2) reduce the levels of LDL whereas those rich in oleic (n-9,18:1) are considered 'neutral'. However, LDL enriched in linoleic acid have been reported to be more vulnerable to free radical-mediated oxidation than those enriched in oleic, a potentially atherogenic property. The effect of dietary fats on other properties of LDL that may also modulate atherogenesis, such as size and capacity to interact with intima components, are not well established. We explored here how a change from an olive oil-rich diet (OO) to a sunflower oil-rich one (SFO) affects these parameters in a community with a traditional Mediterranean diet. Eighteen free-living volunteers were placed for 3 weeks on a diet with 31% of caloric intake as sunflower oil and then shifted for an additional 3 weeks to a diet in which OO provided 30.5% of the calories. The LDL after SFO had a fatty acids ratio of (18:2 + 18:3 + 20:4) to (16:0 + 16:1 + 18:0 + 18:1) of 1.06 +/- 0.11 compared to 0.73 +/- 0.06 after the OO period. Serum LDL was significantly lower after SFO than after OO. Unexpectedly, copper-catalyzed oxidation of LDL from the SFO period was significantly less than that of the particles from the OO period. The resistance to oxidation of LDL of the SFO and OO period related to alterations in content of the antioxidants alpha-tocopherol, beta-carotene and retinol, in addition to changes in size and fatty acids composition. In vitro binding of LDL to human arterial proteoglycans was also significantly lower for the SFO-LDL than the OO-LDL, a result that can also be attributed to the larger size of the SFO-LDL. Therefore, three properties of LDL: circulating levels, oxidizability, and affinity with intima proteoglycans, that may modulate its atherogenicity, were shifted in a favorable direction by diets rich in linoleic acid and natural antioxidants.

Deep learning strategy for accurate carotid intima-media thickness measurement: An ultrasound study on Japanese diabetic cohort.

PubMed

Biswas, Mainak; Kuppili, Venkatanareshbabu; Araki, Tadashi; Edla, Damodar Reddy; Godia, Elisa Cuadrado; Saba, Luca; Suri, Harman S; Omerzu, Tomaž; Laird, John R; Khanna, Narendra N; Nicolaides, Andrew; Suri, Jasjit S

2018-07-01

The carotid intima-media thickness (cIMT) is an important biomarker for cardiovascular diseases and stroke monitoring. This study presents an intelligence-based, novel, robust, and clinically-strong strategy that uses a combination of deep-learning (DL) and machine-learning (ML) paradigms. A two-stage DL-based system (a class of AtheroEdge™ systems) was proposed for cIMT measurements. Stage I consisted of a convolution layer-based encoder for feature extraction and a fully convolutional network-based decoder for image segmentation. This stage generated the raw inner lumen borders and raw outer interadventitial borders. To smooth these borders, the DL system used a cascaded stage II that consisted of ML-based regression. The final outputs were the far wall lumen-intima (LI) and media-adventitia (MA) borders which were used for cIMT measurements. There were two sets of gold standards during the DL design, therefore two sets of DL systems (DL1 and DL2) were derived. A total of 396 B-mode ultrasound images of the right and left common carotid artery were used from 203 patients (Institutional Review Board approved, Toho University, Japan). For the test set, the cIMT error for the DL1 and DL2 systems with respect to the gold standard was 0.126 ± 0.134 and 0.124 ± 0.100 mm, respectively. The corresponding LI error for the DL1 and DL2 systems was 0.077 ± 0.057 and 0.077 ± 0.049 mm, respectively, while the corresponding MA error for DL1 and DL2 was 0.113 ± 0.105 and 0.109 ± 0.088 mm, respectively. The results showed up to 20% improvement in cIMT readings for the DL system compared to the sonographer's readings. Four statistical tests were conducted to evaluate reliability, stability, and statistical significance. The results showed that the performance of the DL-based approach was superior to the nonintelligence-based conventional methods that use spatial intensities alone. The DL system can be used for stroke risk assessment during routine or clinical trial modes. Copyright © 2018 Elsevier Ltd. All rights reserved.

The key role of exudative lesions and their encapsulation: lessons learned from the pathology of human pulmonary tuberculosis.

PubMed

Cardona, Pere-Joan

2015-01-01

A review of the pathology of human pulmonary TB cases at different stages of evolution in the pre-antibiotic era suggests that neutrophils play an instrumental role in the progression toward active TB. This progression is determined by the type of lesion generated. Thus, exudative lesions, in which neutrophils are the major cell type, are both triggered by and induce local high bacillary load, and tend to enlarge and progress toward liquefaction and cavitation. In contrast, proliferative lesions are triggered by low bacillary loads, mainly comprise epithelioid cells and fibroblasts and tend to fibrose, encapsulate and calcify, thus controlling the infection. Infection of the upper lobes is key to the progression toward active TB for two main reasons, namely poor breathing amplitude, which allows local bacillary accumulation, and the high mechanical stress to which the interlobular septae (which enclose secondary lobes) are submitted, which hampers their ability to encapsulate lesions. Overall, progressing factors can be defined as internal (exudative lesion, local bronchogenous dissemination, coalescence of lesions), with lympho-hematological dissemination playing a very limited role, or external (exogenous reinfection). Abrogating factors include control of the bacillary load and the local encapsulation process, as directed by interlobular septae. The age and extent of disease depend on the quality and speed with which lesions liquefy and disseminate bronchially, the volume of the slough, and the amount and distribution of the sloughing debris dispersed.

The key role of exudative lesions and their encapsulation: lessons learned from the pathology of human pulmonary tuberculosis

PubMed Central

Cardona, Pere-Joan

2015-01-01

A review of the pathology of human pulmonary TB cases at different stages of evolution in the pre-antibiotic era suggests that neutrophils play an instrumental role in the progression toward active TB. This progression is determined by the type of lesion generated. Thus, exudative lesions, in which neutrophils are the major cell type, are both triggered by and induce local high bacillary load, and tend to enlarge and progress toward liquefaction and cavitation. In contrast, proliferative lesions are triggered by low bacillary loads, mainly comprise epithelioid cells and fibroblasts and tend to fibrose, encapsulate and calcify, thus controlling the infection. Infection of the upper lobes is key to the progression toward active TB for two main reasons, namely poor breathing amplitude, which allows local bacillary accumulation, and the high mechanical stress to which the interlobular septae (which enclose secondary lobes) are submitted, which hampers their ability to encapsulate lesions. Overall, progressing factors can be defined as internal (exudative lesion, local bronchogenous dissemination, coalescence of lesions), with lympho-hematological dissemination playing a very limited role, or external (exogenous reinfection). Abrogating factors include control of the bacillary load and the local encapsulation process, as directed by interlobular septae. The age and extent of disease depend on the quality and speed with which lesions liquefy and disseminate bronchially, the volume of the slough, and the amount and distribution of the sloughing debris dispersed. PMID:26136741

'They don't just come for Machu Picchu': locals' views of tourist-local sexual relationships in Cuzco, Peru.

PubMed

Bauer, Irmgard

2008-08-01

Sexual and romantic relationships between local people and tourists have long taken place. Such encounters are not a modern phenomenon, but the potential of sexually transmitted infections (STIs), including HIV/AIDS, warrants greater research into the issue. This paper analyses local people's views of local-tourist relationships in Cuzco/Peru. Data were obtained through in-depth interviews, participant and non-participant observation and informal discussions. Attraction based on physical difference was reportedly the main trigger for such relationships. Emerging themes discussed include issues of self-esteem, strategies of approach, tourists' motives, emotional involvement and expectations from such encounters. Levels of unprotected sexual behaviour and lack of STI awareness are of sufficient concern to recommend urgent action. Suggestions for sexual health education are made with particular emphasis on targeting local people involved in the tourism and hospitality industries.

Enzyme-Controlled Nanodevice for Acetylcholine-Triggered Cargo Delivery Based on Janus Au-Mesoporous Silica Nanoparticles.

PubMed

Llopis-Lorente, Antoni; Díez, Paula; de la Torre, Cristina; Sánchez, Alfredo; Sancenón, Félix; Aznar, Elena; Marcos, María D; Martínez-Ruíz, Paloma; Martínez-Máñez, Ramón; Villalonga, Reynaldo

2017-03-28

This work reports a new gated nanodevice for acetylcholine-triggered cargo delivery. We prepared and characterized Janus Au-mesoporous silica nanoparticles functionalized with acetylcholinesterase on the Au face and with supramolecular β-cyclodextrin:benzimidazole inclusion complexes as caps on the mesoporous silica face. The nanodevice is able to selectively deliver the cargo in the presence of acetylcholine via enzyme-mediated acetylcholine hydrolysis, locally lowering the pH and opening the supramolecular gate. Given the key role played by ACh and its relation with Parkinson's disease and other nervous system diseases, we believe that these findings could help design new therapeutic strategies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of small earthquakes with dense array data: example from the San Jacinto fault zone, southern California

NASA Astrophysics Data System (ADS)

Meng, Haoran; Ben-Zion, Yehuda

2018-01-01

We present a technique to detect small earthquakes not included in standard catalogues using data from a dense seismic array. The technique is illustrated with continuous waveforms recorded in a test day by 1108 vertical geophones in a tight array on the San Jacinto fault zone. Waveforms are first stacked without time-shift in nine non-overlapping subarrays to increase the signal-to-noise ratio. The nine envelope functions of the stacked records are then multiplied with each other to suppress signals associated with sources affecting only some of the nine subarrays. Running a short-term moving average/long-term moving average (STA/LTA) detection algorithm on the product leads to 723 triggers in the test day. Using a local P-wave velocity model derived for the surface layer from Betsy gunshot data, 5 s long waveforms of all sensors around each STA/LTA trigger are beamformed for various incident directions. Of the 723 triggers, 220 are found to have localized energy sources and 103 of these are confirmed as earthquakes by verifying their observation at 4 or more stations of the regional seismic network. This demonstrates the general validity of the method and allows processing further the validated events using standard techniques. The number of validated events in the test day is >5 times larger than that in the standard catalogue. Using these events as templates can lead to additional detections of many more earthquakes.

Response of upper ocean cooling off northeastern Taiwan to typhoon passages

NASA Astrophysics Data System (ADS)

Zheng, Zhe-Wen; Zheng, Quanan; Gopalakrishnan, Ganesh; Kuo, Yi-Chun; Yeh, Ting-Kuang

2017-07-01

A comprehensive investigation of the typhoon induced upper ocean processes and responses off northeastern Taiwan was conducted. Using the Regional Ocean Modeling System, the upper ocean responses of all typhoons striking Taiwan between 2005 and 2013 were simulated. In addition to Kuroshio intrusion, the present study demonstrates another important mechanism of typhoon induced near-inertial currents over the continental shelf of East China Sea, which can also trigger a distinct cooling (through entrainment mixing) within this region. Results indicate that the processes of typhoon inducing distinct cooling off northeastern Taiwan are conditional phenomena (only ∼12% of typhoons passing Taiwan triggered extreme cooling there). Subsequently, by executing a series of sensitivity experiments and systematic analyses on the behaviors and background conditions of all those typhoon cases, key criteria determining the occurrences of cooling through both mechanisms were elucidated. Occurrences of cooling through the Kuroshio intrusion mechanism are determined mainly by the strength of the local wind over northeastern Taiwan. A distinct cooling triggered by enhanced near-inertial currents is shown to be associated with the process of wind-current resonance. Both processes of Kuroshio intrusion and enhanced near-inertial currents are dominated by wind forcing rather than upper oceanic conditions. Based on the recent findings on the possible dynamic linkage between sea surface temperature near northeast Taiwan and local weather systems, the results elucidated in this study lay the foundation for further improvement in the regional weather prediction surrounding northeast Taiwan.

Predictive performance of rainfall thresholds for shallow landslides in Switzerland from gridded daily data

NASA Astrophysics Data System (ADS)

Leonarduzzi, Elena; Molnar, Peter; McArdell, Brian W.

2017-08-01

A high-resolution gridded daily precipitation data set was combined with a landslide inventory containing over 2000 events in the period 1972-2012 to analyze rainfall thresholds which lead to landsliding in Switzerland. We colocated triggering rainfall to landslides, developed distributions of triggering and nontriggering rainfall event properties, and determined rainfall thresholds and intensity-duration ID curves and validated their performance. The best predictive performance was obtained by the intensity-duration ID threshold curve, followed by peak daily intensity Imax and mean event intensity Imean. Event duration by itself had very low predictive power. A single country-wide threshold of Imax = 28 mm/d was extended into space by regionalization based on surface erodibility and local climate (mean daily precipitation). It was found that wetter local climate and lower erodibility led to significantly higher rainfall thresholds required to trigger landslides. However, we showed that the improvement in model performance due to regionalization was marginal and much lower than what can be achieved by having a high-quality landslide database. Reference cases in which the landslide locations and timing were randomized and the landslide sample size was reduced showed the sensitivity of the Imax rainfall threshold model. Jack-knife and cross-validation experiments demonstrated that the model was robust. The results reported here highlight the potential of using rainfall ID threshold curves and rainfall threshold values for predicting the occurrence of landslides on a country or regional scale with possible applications in landslide warning systems, even with daily data.

Subclinical Carotid Atherosclerosis in Asymptomatic Subjects With Type 2 Diabetes Mellitus.

PubMed

Rubinat, Esther; Marsal, Josep Ramon; Vidal, Teresa; Cebrian, Cristina; Falguera, Mireia; Vilanova, Ma Belen; Betriu, Àngels; Fernández, Elvira; Franch, Josep; Mauricio, Dídac

2016-01-01

Subjects with type 2 diabetes mellitus are considered to be at high risk for cardiovascular disease. The identification of carotid atherosclerosis is a validated surrogate marker of cardiovascular disease. Nurses are key professionals in the improvement and intensification of cardiovascular preventive strategies. The aim is to study the presence of carotid atherosclerosis in a group of asymptomatic subjects with type 2 diabetes mellitus and no previous clinical cardiovascular disease. A total of 187 patients with type 2 diabetes mellitus and 187 age- and sex-matched subjects without type 2 diabetes mellitus were studied in this cross-sectional, observational, cohort study. Standard operational procedures were applied by the nursing team regarding physical examination and carotid ultrasound assessment. Common, bulb, and internal carotid arteries were explored by measuring intima-media thickness and identifying atherosclerotic plaques. Carotid intima-media thickness (c-IMT) and carotid plaque prevalence were significantly greater in diabetic subjects than in the control group. Carotid plaques and c-IMT were more frequent in men than in women and increased with increasing age. In the multivariate analysis, age, gender, waist circumference, systolic blood pressure, and hypercholesterolemia were positively associated with c-IMT, whereas age, gender, and weight were positively associated with carotid plaque. The current nurse-led study shows that subjects with type 2 diabetes mellitus have a high prevalence of subclinical atherosclerosis that is associated with cardiovascular risk factors.

[Lower is better: ENHANCE affair].

PubMed

Scardi, Sabino; Umari, Paolo; D'Agata, Bianca Maria

2008-06-01

Ezetimibe lowers the intestinal absorption of cholesterol, being complementary to the effects of statin. To check its efficacy in lowering the carotid intima-media thickness, in 2002 a multicenter international trial called ENHANCE was started, in order to assess by ultrasound the regression of atherosclerotic plaques. The protocol tested the use of simvastatin 80 mg + placebo versus simvastatin 80 mg + ezetimibe 10 mg in 720 randomized patients. Both drugs were well tolerated. Combination therapy was associated with a larger reduction in LDL cholesterol, but there were no differences in the intima-media thickness measured at three sites in the carotid arteries, nor differences in cardiovascular events between the two groups in the trial. These results provoked disappointment of sponsors (Merck, Schering Plough) who, although the results of the trial were available since march 2007, delayed official communication of about 18 months. This led to speculations and rumors among media, American Government, cardiologic scientific associations, and consequences in the Ezetimibe market and at Wall Street. In particular, the American College of Cardiology didn't accept the communication of ENHANCE results to the Late Breaking Trial Session of the Chicago congress, diverting it to another secondary forum. In conclusion, the experience of the ENHANCE trial suggests to pharmaceutical companies, researchers, clinicians, scientific companies and media a deep meditation in order to avoid in the future similar problems in the management of results of medical research.

Obesity and overweight associated with increased carotid diameter and decreased arterial function in young otherwise healthy men.

PubMed

Kappus, Rebecca M; Fahs, Christopher A; Smith, Denise; Horn, Gavin P; Agiovlasitis, Stomatis; Rossow, Lindy; Jae, Sae Y; Heffernan, Kevin S; Fernhall, Bo

2014-04-01

Obesity is linked to cardiovascular disease, stroke, increased mortality and vascular remodeling. Although increased arterial diameter is associated with multiple cardiovascular risk factors and obesity, it is unknown whether lumen enlargement is accompanied by unfavorable vascular changes in young and otherwise healthy obese individuals. The purpose of this study was to compare carotid and brachial artery diameter, blood pressure, arterial stiffness, and endothelial function in young, apparently healthy, normal-weight, overweight, and obese male subjects. One hundred sixty-five male subjects (27.39±0.59 years) were divided into 3 groups (normal weight, overweight, and obese) according to body mass index. Subjects underwent cardiovascular measurements to determine arterial diameter, function, and stiffness. After adjusting for age, the obese group had significantly greater brachial, carotid, and aortic pressures, brachial pulse wave velocity, carotid intima media thickness, and carotid arterial diameter compared with both the overweight and normal-weight groups. Obesity is associated with a much worse arterial profile, as an increased carotid lumen size was accompanied by higher blood pressure, greater arterial stiffness, and greater carotid intima media thickness in obese compared with overweight or normal-weight individuals. These data suggest that although obesity may be a factor in arterial remodeling, such remodeling is also accompanied by other hemodynamic and arterial changes consistent with reduced arterial function and increased cardiovascular risk.

Obesity and Overweight Associated With Increased Carotid Diameter and Decreased Arterial Function in Young Otherwise Healthy Men

PubMed Central

2014-01-01

BACKGROUND Obesity is linked to cardiovascular disease, stroke, increased mortality and vascular remodeling. Although increased arterial diameter is associated with multiple cardiovascular risk factors and obesity, it is unknown whether lumen enlargement is accompanied by unfavorable vascular changes in young and otherwise healthy obese individuals. The purpose of this study was to compare carotid and brachial artery diameter, blood pressure, arterial stiffness, and endothelial function in young, apparently healthy, normal-weight, overweight, and obese male subjects. METHODS One hundred sixty-five male subjects (27.39±0.59 years) were divided into 3 groups (normal weight, overweight, and obese) according to body mass index. Subjects underwent cardiovascular measurements to determine arterial diameter, function, and stiffness. RESULTS After adjusting for age, the obese group had significantly greater brachial, carotid, and aortic pressures, brachial pulse wave velocity, carotid intima media thickness, and carotid arterial diameter compared with both the overweight and normal-weight groups. CONCLUSIONS Obesity is associated with a much worse arterial profile, as an increased carotid lumen size was accompanied by higher blood pressure, greater arterial stiffness, and greater carotid intima media thickness in obese compared with overweight or normal-weight individuals. These data suggest that although obesity may be a factor in arterial remodeling, such remodeling is also accompanied by other hemodynamic and arterial changes consistent with reduced arterial function and increased cardiovascular risk. PMID:24048148

The Influence of Abdominal and Ectopic Fat Accumulation on Carotid Intima-Media Thickness: A Chongqing Study.

PubMed

Yi, Xu; Liu, Yu-Hui; Zhou, Xin-Fu; Wang, Yan-Jiang; Deng, Juan; Liu, Juan; He, Hong-Bo; Xu, Zhi-Qiang

2018-04-16

To investigate the effects of abdominal obesity (AO) and nonalcoholic fatty liver disease (NAFLD) with or without AO on carotid arteries by determining carotid intima-media thickness (CIMT). A total of 2745 Chinese Han adults (aged between 40 and 50 years old) were recruited and divided into 4 groups: (1) NW-no NAFL group: the normal body weight without NAFLD (n = 1888); (2) AO-no NAFL group: AO without NAFLD (n = 259); (3) NW-with NAFL group: NAFLD without AO (n = 93); and (4) AO-with NAFL group: AO with NAFLD (n = 505). The CIMT rate of each group was compared among 4 groups and the regression analysis was further used to correct confounders. We found that the NW-with NAFL group had a significantly higher CIMT rate than the AO-no NAFL group ([.87 ± .31] versus [.72 ± .29] P < .01) and the AO-with NAFL group ([.87 ± .31] versus [.79 ± .26], P < .01). The ectopic liver fat accumulation may increase the risk of atherosclerosis. Therefore, screening NAFLD in the population with normal weight may be beneficial for the prevention of atherosclerosis at an early stage. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

LOX-1 ligands containing apolipoprotein B and carotid intima-media thickness in middle-aged community-dwelling US Caucasian and Japanese men

PubMed Central

Okamura, Tomonori; Sekikawa, Akira; Sawamura, Tatsuya; Kadowaki, Takashi; Barinas-Mitchell, Emma; Mackey, Rachel H.; Kadota, Aya; Evans, Rhobert W.; Edmundowicz, Daniel; Higashiyama, Aya; Nakamura, Yasuyuki; Abbott, Robert D.; Miura, Katsuyuki; Fujiyoshi, Akira; Fujita, Yoshiko; Murakami, Yoshitaka; Miyamatsu, Naomi; Kakino, Akemi; Maegawa, Hiroshi; Murata, Kiyoshi; Horie, Minoru; Mitsunami, Kenichi; Kashiwagi, Atsunori; Kuller, Lewis H.; Ueshima, Hirotsugu

2013-01-01

Objective The serum level of LOX-1 ligand containing ApoB (LAB) may reflect atherogenicity better than LDL cholesterol (LDLC), total LDL particles and usual measurement of oxidized LDL. The association between LAB and intima-media thickness (IMT) of carotid artery was investigated by ultrasound in US and Japan men. Methods Participants were 297 US Caucasian and 310 Japanese men, aged 40 to 49 years without past history of cardiovascular disease. Serum LAB levels were measured by ELISAs with recombinant LOX-1 and monoclonal anti–apolipoprotein B antibody. Results Serum LAB levels [median (interquartile range), μg/L] were 1,321 (936, 1730) in US Caucasians and 940 (688, 1259) in Japanese. For Caucasian men, average IMT was higher in higher LAB quartile, which was 0.653, 0.667, 0.688, and 0.702 mm, respectively (p for trend= 0.02). Linear regression analysis showed serum LAB was significantly associated with IMT after adjustment for LDLC or total LDL particles in addition to other traditional or novel risk factors for atherosclerosis such as C-reactive protein. However, there was no significant relationship between LAB and IMT in Japanese men. Conclusion Serum LAB, a new candidate biomarker for residual risk, was associated with an increased carotid IMT in US Caucasian men independently of various risk factors; however, ethnic difference should be clarified in the future. PMID:23683938

Risk factors correlated with plantar pressure in Chinese patients with type 2 diabetes.

PubMed

Qiu, Xuan; Tian, De-Hu; Han, Chang-Ling; Chen, Wei; Wang, Zhan-Jian; Mu, Zhen-Yun; Li, Xu; Liu, Kuan-Zhi

2013-12-01

Plantar pressure is a key factor for predicting ulceration in the foot of a diabetes patient. We recruited a group of 100 Chinese patients with type 2 diabetes and an age-, sex-, weight-, and height-matched group of 100 Chinese subjects without diabetes. We obtained plantar pressure data using a Footscan(®) gait system (RsScan International, Olen, Belgium) when the subjects with and without diabetes walked barefoot across a sensor platform. We recorded the maximum force, maximum pressure, impulse, pressure-time integral, and loading rate from 10 regions of the foot. We collected the data of 11 history-based variables, 10 anthropometric variables, and three metabolic variables regarding the clinical characteristics of the diabetes patients. Weight was identified as a determining factor for high plantar pressure. Height, the Neuropathy Symptom Score (NSS), and ankle-brachial index (ABI) were correlated positively with plantar pressure measurements, respectively. The sex, history of ulcer and callus, intima-media membrane of the lower limb blood vessels, and fasting blood glucose (FBG) could also explain a portion of the variability of the plantar pressure measurements. However, the correlations were low or weak. High plantar pressure in diabetes patients could be predicted, in part, based on weight, height, NSS, ABI, sex, history of ulcer and callus, intima-media membrane of the lower limb blood vessels, and FBG. Therefore, interventions should be taken specifically before high plantar pressure emerges.

Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men.

PubMed

Yang, Shu-Yu; Li, Xue-Jun; Zhang, Wei; Liu, Chang-Qin; Zhang, Hui-Jie; Lin, Jin-Rong; Yan, Bing; Yu, Ya-Xin; Shi, Xiu-Lin; Li, Can-Dong; Li, Wei-Hua

2012-06-01

To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD). One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated. Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old. In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.

Free Triiodothyronine Concentrations are Inversely Associated with Elevated Carotid Intima-Media Thickness in Middle-Aged and Elderly Chinese Population.

PubMed

Zhou, Yulin; Zhao, Liebin; Wang, Tiange; Hong, Jie; Zhang, Jie; Xu, Baihui; Huang, Xiaolin; Xu, Min; Bi, Yufang

2016-01-01

Increased carotid artery intima media thickness (C-IMT) is an early feature of atherosclerosis. It has been reported to be altered in patients with thyroid dysfunction, and the evidence is still controversial. The present study aimed to explore the relationship between C-IMT and possible variations in thyroid function in Chinese adults aged 40 years and above. A community-based cross-sectional study was conducted among 2276 non-diabetic participants. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were determined by chemiluminescent microparticle immunoassay. The prevalence of elevated C-IMT decreased according to FT3 quartiles (29.8%, 24.3%, 24.2%, and 22.2%, P for trend=0.005). In both univariate and multivariate linear regression analyses, FT3 levels were inversely associated with C-IMT (both P values ≤ 0.002). Multivariate-adjusted logistic regression analysis showed that high FT3 levels were associated with low prevalent elevated C-IMT. The adjusted odds ratio for elevated C-IMT was 0.71 (95% confidence interval, 0.52-0.99, P=0.04) when comparing the highest with the lowest quartile of FT3. Serum FT3 levels were inversely associated with elevated C-IMT in middle-aged and elderly Chinese adults without diabetes, independent of traditional risk factors for atherosclerosis.

Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study.

PubMed

Chooi, K Y; Comerford, A; Sherwin, S J; Weinberg, P D

2016-06-01

The hydraulic resistances of the intima and media determine water flux and the advection of macromolecules into and across the arterial wall. Despite several experimental and computational studies, these transport processes and their dependence on transmural pressure remain incompletely understood. Here, we use a combination of experimental and computational methods to ascertain how the hydraulic permeability of the rat abdominal aorta depends on these two layers and how it is affected by structural rearrangement of the media under pressure. Ex vivo experiments determined the conductance of the whole wall, the thickness of the media and the geometry of medial smooth muscle cells (SMCs) and extracellular matrix (ECM). Numerical methods were used to compute water flux through the media. Intimal values were obtained by subtraction. A mechanism was identified that modulates pressure-induced changes in medial transport properties: compaction of the ECM leading to spatial reorganization of SMCs. This is summarized in an empirical constitutive law for permeability and volumetric strain. It led to the physiologically interesting observation that, as a consequence of the changes in medial microstructure, the relative contributions of the intima and media to the hydraulic resistance of the wall depend on the applied pressure; medial resistance dominated at pressures above approximately 93 mmHg in this vessel. © 2016 The Authors.

Childhood hyperactivity as a predictor of carotid artery intima media thickness over a period of 21 years: the cardiovascular risk in young Finns study.

PubMed

Keltikangas-Järvinen, Liisa; Pulkki-Råback, Laura; Puttonen, Sampsa; Viikari, Jorma; Raitakari, Olli T

2006-01-01

We investigated whether childhood temperament was able to predict carotid artery intima media thickness (IMT) and/or its risk factors in adulthood 21 years later. The subjects were the three youngest age cohorts of the population-based sample of the Cardiovascular Risk in Young Finns study, i.e., those who were aged 3 to 9 years (n = 708) at the baseline. IMT was assessed by ultrasound, and temperament in terms of negative emotionality, hyperactivity, and sociability (following Buss and Plomin). In addition, the levels of traditional risk factors for atherosclerosis were measured in both childhood and adulthood. Childhood temperament was found to predict adulthood risk factors such as smoking in both genders and body mass index (BMI), systolic blood pressure (SBP), and educational level in women. In women, childhood hyperactivity predicted adulthood IMT after adjustment for childhood and adulthood risk factors for atherosclerosis. These findings suggest that temperament may contribute to the development of IMT in two ways: indirectly through risk factors in both genders and in women directly through a mechanism that is not considered in the present study. There were no significant gender-related differences in temperament, but it seemed to play different roles in different genders. Hyperactivity was a greater risk for girls than for boys.

Effects of Methotrexate on Carotid Intima-media Thickness in Patients with Rheumatoid Arthritis

PubMed Central

Kim, Hyun-Je; Kim, Min-Jung; Lee, Choong-Ki

2015-01-01

The purpose of this study was to evaluate the effects of rheumatoid arthritis (RA) and antirheumatic drugs on atherosclerosis by comparing carotid intima-media thickness (CIMT) as an indicator for cardiovascular diseases (CVD). This study included 44 female RA patients who met the 2010 ACR/EULAR criteria and age-matched 22 healthy females. CIMT was measured on both carotid arteries using a B-mode ultrasound scan. The mean value of both sides was taken as the CIMT of the subject. The CIMT was evaluated according to the use of drugs, disease activity and CVD risk factors in RA patients as a case-control study. Higher CIMT was observed in RA patients as compared with healthy subjects (0.705 ± 0.198 mm, 0.611 ± 0.093 mm, respectively, P < 0.05). With adjustment for the CVD risk factors, disease activity and the use of anti-rheumatic drugs, methotrexate (MTX) only showed a favorable effect on CIMT in RA. A significantly lower CIMT was observed in RA with MTX as compared with RA without MTX (0.644 ± 0.136 mm, 0.767 ± 0.233 mm, respectively, P < 0.05). The effects were correlated with MTX dosage (β = -0.029, P < 0.01). The use of MTX should be considered in high priority not only to control arthritis but also to reduce the RA-related CVD risk to mortality. PMID:26539002

Heritability of carotid intima-media thickness: a twin study.

PubMed

Zhao, Jinying; Cheema, Faiz A; Bremner, J Douglas; Goldberg, Jack; Su, Shaoyong; Snieder, Harold; Maisano, Carisa; Jones, Linda; Javed, Farhan; Murrah, Nancy; Le, Ngoc-Anh; Vaccarino, Viola

2008-04-01

To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors. We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75+/-0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62-0.69) than in DZ twins (0.37; 95% CI, 0.29-0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54-0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39-0.73). Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors.

Hypercholesterolemia increases plasma saturated and n-6 fatty acids altering prostaglandin homeostasis and promotes endothelial dysfunction in rabbits.

PubMed

Medina, M; Alberto, M R; Sierra, L; Van Nieuwenhove, C; Saad, S; Isla, M I; Jerez, S

2014-07-01

The present study evaluated the plasma fatty acid levels and the vascular prostaglandin (PG) release in a rabbit model of early hypercholesterolemia with endothelial dysfunction. Rabbits were fed either a control diet (CD) or a diet containing 1 % cholesterol (HD) for 5-6 weeks. The level of fatty acids was measured in plasma. The levels of PG and nitric oxide (NO) released from the aorta were also determined. Vascular morphology of the aorta was characterized by intima and media thickness measurements. The rabbits fed with HD had higher levels of arachidonic acid (ARA) and lower levels of oleic acid. The linoleic acid level was unchanged. PGI(2) and NO were diminished and PGF(2α) levels, the PGI(2)/TXA(2) ratio and the intima/media ratio were increased in rabbits fed with HD. In conclusion, feeding HD for a short period increased ARA plasma levels and unbalanced release of vasodilator/vasoconstrictor PG redirected the pathway to vasoconstrictor metabolite release. These lipid metabolism alterations in addition to the reduced NO levels and the moderate changes in the vascular morphology contributed to the endothelial dysfunction in this animal model. Therefore, the present findings support the importance of early correction or prevention of high cholesterol levels to disrupt the endothelial dysfunction process that leads to cardiovascular disease.

Association between Micronutrients Intake/Status and Carotid Intima Media Thickness: A Systematic Review.

PubMed

Hosseini, Banafshe; Saedisomeolia, Ahmad; Skilton, Michael R

2017-01-01

Carotid intima media thickness (IMT) is a noninvasive marker of the extent and severity of subclinical atherosclerosis. Micronutrient intake may affect atherosclerosis and play a major role in the development of cardiovascular diseases (CVDs). The primary aim of this review was to synthesize the evidence regarding the association between carotid IMT and selected micronutrients. The authors searched PubMed, Cochrane, and EMBASE databases from inception to June 2016 for selected micronutrients, CVD, carotid IMT, and antioxidants. Thirty-five original studies met the inclusion criteria and were reviewed following preferred reporting items for systematic review and meta-analysis guidelines. Although not all studies found consistent results, the weight of the evidence suggests that high intakes and/or circulatory levels of magnesium, as well as vitamin D and the vitamin B group, may be associated with lower carotid IMT or reduced progression of carotid IMT. The majority of studies did not find any significant association between vitamin E and C and carotid IMT. Less evidence was available for associations of retinol, zinc, and iron with carotid IMT. In general, the current evidence concerning micronutrient intake and carotid IMT is largely inconclusive. Pragmatic clinical trials are required to determine whether dietary or supplemental intake of specific micronutrients alters carotid IMT, which is a surrogate measure of cardiovascular risk. Copyright © 2017 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

[Analysis of 24-hour blood pressure profile, heart rate variability and carotid atherosclerosis in hypertensive patients among native and nonnative population living in Yamalo-Nenets autonomous district].

PubMed

Gapon, L I; Sereda, T V; Leont'eva, A V

2014-01-01

To study special characteristics of the course of arterial hypertension (AH) among native and nonnative population of Yamalo-Nenets autonomous district. We examined 100 residents of Far North with AH (men and women aged 21-55, mean age 44.08 ± 1.15 years). All patients were divided into 2 equal groups by 50 subjects: group I consisted of representatives of native and group II--nonnative population. Examination was carried out in outpatient clinic in Salekhard and included 24-hour ambulatory blood pressure monitoring (ABPM), registration of heart rate variability, duplex scanning of brachiocephalic arteries, and assessment of blood lipid profile. The groups were matched by age, gender and disease duration. Analysis of heart rate variability detected significant degree of strain of regulatory systems in most patients of both groups. According to results of ABPM "non-dipper" patients prevailed in group I compared to group II (p = 0.01). Common carotid artery intima-media complex was significantly greater compared to normal value in all patients; it was thicker in group I (p < 0.03), but number of carotid artery stenoses was similar in both groups. No dyslipoproteinemia was detected. Compared with group of representatives of nonnative (adopted) population group of native subjects with AH was characterized by greater carotid intima media thickness and prevalence of "non-dipper" patients.

The Relationship between Lichen Planus and Carotid Intima Media Thickness.

PubMed

C, Koseoglu; M, Erdogan; G, Koseoglu; O, Kurmus; Ag, Ertem; Th, Efe; Gi, Kurmus; T, Durmaz; T, Keles; E, Bozkurt

2016-11-01

Lichen planus (LP) is a chronic inflammatory disease. Although the association between chronic inflammation and subclinical atherosclerosis has been reported in the literature, the relationship between LP and carotid intima media thickness (CIMT) has not been previously investigated. The aim of this study was to investigate the relationship between LP and CIMT. One hundred eleven LP patients and 105 controls were enrolled in the study. Then, CIMT examination was performed with an ultrasonography device. Cross-sectional associations of LP with CIMT were analyzed using linear regression models adjusted for related confounders. No statistical difference was found between LP and the controls except for the female gender, white blood cell, LDL cholesterol and triglycerides (p = 0.046, p = 0.019, p = 0.011 and p = 0.013, respectively). Significant difference was found between the groups in terms of CIMT (0.90 ± 0.2 mm vs. 0.61 ± 0.3 mm, p = 0.001). CIMT was correlated with longevity of the LP, but we did not find LP to be an independent predictor of increased CIMT in logistic regression analysis (r = 0.449, p < 0.001, β = -0.117, p = 0.092; respectively). The results of our study suggested that LP was associated with increased mean CIMT, and furthermore that CIMT was correlated with longevity of LP. However, LP was not an independent predictor of increased CIMT.

The Relationship between Lichen Planus and Carotid Intima Media Thickness

PubMed Central

C, Koseoglu; M, Erdogan; G, Koseoglu; O, Kurmus; AG, Ertem; TH, Efe; GI, Kurmus; T, Durmaz; T, Keles; E, Bozkurt

2016-01-01

Background Lichen planus (LP) is a chronic inflammatory disease. Although the association between chronic inflammation and subclinical atherosclerosis has been reported in the literature, the relationship between LP and carotid intima media thickness (CIMT) has not been previously investigated. The aim of this study was to investigate the relationship between LP and CIMT. Methods One hundred eleven LP patients and 105 controls were enrolled in the study. Then, CIMT examination was performed with an ultrasonography device. Cross-sectional associations of LP with CIMT were analyzed using linear regression models adjusted for related confounders. Results No statistical difference was found between LP and the controls except for the female gender, white blood cell, LDL cholesterol and triglycerides (p = 0.046, p = 0.019, p = 0.011 and p = 0.013, respectively). Significant difference was found between the groups in terms of CIMT (0.90 ± 0.2 mm vs. 0.61 ± 0.3 mm, p = 0.001). CIMT was correlated with longevity of the LP, but we did not find LP to be an independent predictor of increased CIMT in logistic regression analysis (r = 0.449, p < 0.001, β = -0.117, p = 0.092; respectively). Conclusions The results of our study suggested that LP was associated with increased mean CIMT, and furthermore that CIMT was correlated with longevity of LP. However, LP was not an independent predictor of increased CIMT. PMID:27899862

Effect of Aerobic versus Resistance Exercise on Pulse Wave Velocity, Intima Media Thickness and Left Ventricular Mass in Obese Adolescents.

PubMed

Horner, Katy; Kuk, Jennifer L; Barinas-Mitchell, Emma; Drant, Stacey; DeGroff, Curt; Lee, SoJung

2015-11-01

A cardiovascular comorbidity in obese adolescents is increased aortic pulse wave velocity (aPWV), carotid intima-media thickness (cIMT) and left ventricular mass (LVM). We investigated in obese adolescents 1) the risk factors associated with aPWV, cIMT and LVM, and 2) the effects of aerobic (AE) versus resistance (RE) exercise alone (without calorie restriction) on aPWV, cIMT, LVM index (LVMI) and cardiometabolic risk factors. Eighty-one obese adolescents (12-18 yrs, BMI ≥95th percentile) were randomized to 3 months of AE (n = 30), RE (n = 27) or a control group (n = 24). Outcome measures included aPWV, cIMT, LVMI, body composition, cardiorespiratory fitness (CRF), blood pressure (BP) and lipids. At baseline, the strongest correlates of aPWV were body weight (r = .31) and diastolic BP (r = .28); of cIMT were body weight (r=0.26) and CRF (r=-0.25); and of LVMI was CRF (r=0.32) after adjusting for sex and race (p < .05 for all). Despite significant reductions in total fat and improvements in CRF in the AE and RE groups, aPWV, cIMT, LVMI, BP, lipids and body weight did not change as compared with controls (p > .05 for all). Interventions of longer duration or together with weight loss may be required to improve these early biomarkers of CVD in obese adolescents.

Adding temporally localized noise can enhance the contribution of target knowledge on contrast detection.

PubMed

Silvestre, Daphné; Cavanagh, Patrick; Arleo, Angelo; Allard, Rémy

2017-02-01

External noise paradigms are widely used to characterize sensitivity by comparing the effect of a variable on contrast threshold when it is limited by internal versus external noise. A basic assumption of external noise paradigms is that the processing properties are the same in low and high noise. However, recent studies (e.g., Allard & Cavanagh, 2011; Allard & Faubert, 2014b) suggest that this assumption could be violated when using spatiotemporally localized noise (i.e., appearing simultaneously and at the same location as the target) but not when using spatiotemporally extended noise (i.e., continuously displayed, full-screen, dynamic noise). These previous findings may have been specific to the crowding and 0D noise paradigms that were used, so the purpose of the current study is to test if this violation of noise-invariant processing also occurs in a standard contrast detection task in white noise. The rationale of the current study is that local external noise triggers the use of recognition rather than detection and that a recognition process should be more affected by uncertainty about the shape of the target than one involving detection. To investigate the contribution of target knowledge on contrast detection, the effect of orientation uncertainty was evaluated for a contrast detection task in the absence of noise and in the presence of spatiotemporally localized or extended noise. A larger orientation uncertainty effect was observed with temporally localized noise than with temporally extended noise or with no external noise, indicating a change in the nature of the processing for temporally localized noise. We conclude that the use of temporally localized noise in external noise paradigms risks triggering a shift in process, invalidating the noise-invariant processing required for the paradigm. If, instead, temporally extended external noise is used to match the properties of internal noise, no such processing change occurs.

The build-up of energetic electrons triggering electron cyclotron emission bursts due to a magnetohydrodynamic mode at the edge of tokamaks

DOE PAGES

Li, Erzhong; Austin, Max E.; White, R. B.; ...

2017-08-21

Intense bursts of electron cyclotron emission (ECE) triggered by magnetohydrodynamic (MHD) instabilities such as edge localized modes (ELMs) have been observed on many tokamaks. On the DIII-D tokamak, it is found that an MHD mode is observed to trigger the ECE bursts in the low collisionality regime at the plasma edge. ORBIT-code simulations have shown that energetic electrons build up due to an interaction between barely trapped electrons with an MHD mode (f = 50 kHz for current case). The energetic tail of the electron distribution function develops a bump within several microseconds for this collisionless case. This behavior dependsmore » on the competition between the perturbing MHD mode and slowing down and pitch angle scattering due to collisions. As a result, for typical DIII-D parameters, the calculated ECE radiation transport predicted by ORBIT is in excellent agreement with ECE measurements, clarifying the electron dynamics of the ECE bursts for the first time.« less

Imaging enzyme-triggered self-assembly of small molecules inside live cells

PubMed Central

Gao, Yuan; Shi, Junfeng; Yuan, Dan; Xu, Bing

2012-01-01

Self-assembly of small molecules in water to form nanofibers, besides generating sophisticated biomaterials, promises a simple system inside cells for regulating cellular processes. But lack of a convenient approach for studying the self-assembly of small molecules inside cells hinders the development of such systems. Here we report a method to image enzyme-triggered self-assembly of small molecules inside live cells. After linking a fluorophore to a self-assembly motif to make a precursor, we confirmed by 31P NMR and rheology that enzyme-triggered conversion of the precursor to a hydrogelator results in the formation of a hydrogel via self-assembly. The imaging contrast conferred by the nanofibers of the hydrogelators allowed the evaluation of intracellular self-assembly; the dynamics, and the localization of the nanofibers of the hydrogelators in live cells. This approach explores supramolecular chemistry inside cells and may lead to new insights, processes, or materials at the interface of chemistry and biology. PMID:22929790

Boosted object hardware trigger development and testing for the Phase I upgrade of the ATLAS Experiment

NASA Astrophysics Data System (ADS)

Stark, Giordon; Atlas Collaboration

2015-04-01

The Global Feature Extraction (gFEX) module is a Level 1 jet trigger system planned for installation in ATLAS during the Phase 1 upgrade in 2018. The gFEX selects large-radius jets for capturing Lorentz-boosted objects by means of wide-area jet algorithms refined by subjet information. The architecture of the gFEX permits event-by-event local pile-up suppression for these jets using the same subtraction techniques developed for offline analyses. The gFEX architecture is also suitable for other global event algorithms such as missing transverse energy (MET), centrality for heavy ion collisions, and ``jets without jets.'' The gFEX will use 4 processor FPGAs to perform calculations on the incoming data and a Hybrid APU-FPGA for slow control of the module. The gFEX is unique in both design and implementation and substantially enhance the selectivity of the L1 trigger and increases sensitivity to key physics channels.

Decentralized event-triggered synchronization of uncertain Markovian jumping neutral-type neural networks with mixed delays.

PubMed

Senan, Sibel; Syed Ali, M; Vadivel, R; Arik, Sabri

2017-02-01

In this study, we present an approach for the decentralized event-triggered synchronization of Markovian jumping neutral-type neural networks with mixed delays. We present a method for designing decentralized event-triggered synchronization, which only utilizes locally available information, in order to determine the time instants for transmission from sensors to a central controller. By applying a novel Lyapunov-Krasovskii functional, as well as using the reciprocal convex combination method and some inequality techniques such as Jensen's inequality, we obtain several sufficient conditions in terms of a set of linear matrix inequalities (LMIs) under which the delayed neural networks are stochastically stable in terms of the error systems. Finally, we conclude that the drive systems synchronize stochastically with the response systems. We show that the proposed stability criteria can be verified easily using the numerically efficient Matlab LMI toolbox. The effectiveness and feasibility of the results obtained are verified by numerical examples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chronic pain in a patient with Ehlers-Danlos syndrome (hypermobility type): The role of myofascial trigger point injections.

PubMed

Tewari, Saipriya; Madabushi, Rajashree; Agarwal, Anil; Gautam, Sujeet K; Khuba, Sandeep

2017-01-01

Chronic widespread musculoskeletal pain is a cardinal symptom in hypermobility type of Ehler Danlos Syndrome (EDS type III). The management of pain in EDS, however, has not been studied in depth. A 30 year old female, known case of EDS, presented to the pain clinic with complaints of severe upper back pain for 6 months. Physical examination of the back revealed two myofascial trigger points over the left rhomboids and the left erector spinae. Local anaesthetic trigger point injections were given at these points, followed by stretching exercises under analgesic cover for the first week. After 1 week the patient reported 60-80% pain relief. This case highlights that we must keep a high index of suspicion for the more treatable causes of pain like myofascial pain syndrome in patients suffering from EDS, and should address it promptly and appropriately in order to maximise patient comfort. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decentralized event-triggered consensus control strategy for leader-follower networked systems

NASA Astrophysics Data System (ADS)

Zhang, Shouxu; Xie, Duosi; Yan, Weisheng

2017-08-01

In this paper, the consensus problem of leader-follower networked systems is addressed. At first, a centralized and a decentralized event-triggered control strategy are proposed, which make the control actuators of followers update at aperiodic invent interval. In particular, the latter one makes each follower requires the local information only. After that, an improved triggering function that only uses the follower's own information and the neighbors' states at their latest event instants is developed to relax the requirement of the continuous state of the neighbors. In addition, the strategy does not require the information of the topology, nor the eigenvalues of the Laplacian matrix. And if the follower does not have direct connection to the leader, the leader's information is not required either. It is analytically shown that by using the proposed strategy the leader-follower networked system is able to reach consensus without continuous communication among followers. Simulation examples are given to show effectiveness of the proposed control strategy.

Combining stress transfer and source directivity: the case of the 2012 Emilia seismic sequence

PubMed Central

Convertito, Vincenzo; Catalli, Flaminia; Emolo, Antonio

2013-01-01

The Emilia seismic sequence (Northern Italy) started on May 2012 and caused 17 casualties, severe damage to dwellings and forced the closure of several factories. The total number of events recorded in one month was about 2100, with local magnitude ranging between 1.0 and 5.9. We investigate potential mechanisms (static and dynamic triggering) that may describe the evolution of the sequence. We consider rupture directivity in the dynamic strain field and observe that, for each main earthquake, its aftershocks and the subsequent large event occurred in an area characterized by higher dynamic strains and corresponding to the dominant rupture direction. We find that static stress redistribution alone is not capable of explaining the locations of subsequent events. We conclude that dynamic triggering played a significant role in driving the sequence. This triggering was also associated with a variation in permeability and a pore pressure increase in an area characterized by a massive presence of fluids. PMID:24177982

Laser-driven localization of collective CO vibrations in metal-carbonyl complexes

NASA Astrophysics Data System (ADS)

Lisaj, Mateusz; Kühn, Oliver

2014-11-01

Using the example of a cobalt dicarbonyl complex it is shown that two perpendicular linearly polarized IR laser pulses can be used to trigger an excitation of the delocalized CO stretching modes, which corresponds to an alternating localization of the vibration within one CO bond. The switching time for localization in either of the two bonds is determined by the energy gap between the symmetric and asymmetric fundamental transition frequencies. The phase of the oscillation between the two local bond excitations can be tuned by the relative phase of the two pulses. The extend of control of bond localization is limited by the anharmonicity of the potential energy surfaces leading to wave packet dispersion. This prevents such a simple pulse scheme from being used for laser-driven bond breaking in the considered example.

Local Turbulence Suppression and Shear Flow Dynamics During qmin-Triggered Internal Transport Barriers on DIII-D

NASA Astrophysics Data System (ADS)

Shafer, M. W.; McKee, G. R.; Schlossberg, D. J.; Austin, M. E.; Burrell, K. H.

2008-11-01

Long-wavelength turbulence (kρi< 1) is locally suppressed simultaneously with a rapid but transient increase in local poloidal flow shear at the appearance of low-order rational qmin surfaces in negative central shear discharges. At these events, reductions in energy transport are observed and Internal Transport Barriers (ITBs) may form. Application of off-axis ECH slows the q-profile evolution and increases ρqmin, both of which enhance turbulence measurements using a new high-sensitivity large-area (8x,8) 2D BES array. The measured transient turbulence suppression is localized to the low-order rational surface (qmin= 2, 5/2, 3, etc.). Measured poloidal flow shear transiently exceeds the turbulence decorrelation rate, which is consistent with shear suppression. The localized suppression zone propagates radially outward, nearly coincident with the low-order surface.

Pedunculated Pulmonary Artery Sarcoma Suggested by Transthoracic Echocardiography.

PubMed

Wang, Xiaobing; Ren, Weidong; Yang, Jun

2016-04-01

Pulmonary artery sarcoma (PAS) is an extremely rare malignancy. It is usually found after it grows large enough to occupy almost the entire lumen of the pulmonary artery and causes serious clinical symptoms. Thus, it is usually difficult to distinguish PAS from pulmonary thromboembolism based on imaging examinations. Few case reports had shown the attachment of PAS to pulmonary artery, a key characteristic for diagnosis, and differential diagnosis of PAS. In this case, we found a PAS, which did not cause local obstruction and some tumor emboli, which obstructed the branches of the pulmonary arteries and caused pulmonary hypertension and clinical symptoms. Transthoracic echocardiography (TTE) revealed a part of the tumor attached to the intima of the main pulmonary artery with a peduncle and had obvious mobility, which was suggestive of PAS and differentiated it from the pulmonary thromboembolism. To our knowledge, this is the first case report of a pedunculated PAS suggested by TTE. Combined with pulmonary artery computed tomography angiography, the diagnosis of PAS is strongly suggested before the operation. This case indicates that TTE could reveal the attachment and mobility of PAS in the main pulmonary and may provide useful information for the diagnosis and differential diagnosis of PAS, especially a pedunculated PAS. © 2015, Wiley Periodicals, Inc.

Strongylus vulgaris (Looss, 1900) in horses in Italy: is it still a problem?

PubMed

Pilo, C; Altea, A; Pirino, S; Nicolussi, P; Varcasia, A; Genchi, M; Scala, A

2012-03-23

A post-mortem survey was carried out on 46 Sardinian horses to evaluate the presence of Strongylus vulgaris and associated pathology. Horses were from local farms and had been treated with broad-spectrum anthelmintics at least 3 times a year. Examination of the cranial mesenteric arterial system (CMAS) showed parasite-induced lesions in all horses. S. vulgaris larvae were found in 39% of examined arteries, while their detection rate in coprocultures was 4%. Histology, carried out on 26 horses, showed mainly chronic and chronic-active lesions. Histometry showed a significant increase in thickness of the arterial wall, in particular of the intima tunic and adventitia tunic of the ileocolic artery and its colic branch. MCV, MCHC and alpha2, beta and gamma globulins were increased in horses with S. vulgaris larvae in the arteries, while the albumin/globulin ratio was decreased. Horses that were positive on faecal examination showed decreased values for RBC, PCV and the albumin/globulin ratio. Although several studies have shown a dramatic decrease of S. vulgaris infection worldwide, our data show that this parasite continues to exert its pathogenic role, even when its detection rate is quite low within the strongyle population infecting horses. Copyright © 2011 Elsevier B.V. All rights reserved.

Early Detection of Heterotopic Ossification for Effective Prevention and Treatment

DTIC Science & Technology

2014-04-01

selectively induced in rat model of myocardial infarction . Inflammation. 2001;25(5):293-300. 20. Tögel F, Isaac J, Hu Z, Weiss K, Westenfelder C. Renal SDF...the development of HO, subtle muscle injuries could trigger SDF-1 build-up locally and MSC recruitment. This project is based on a hypothesis that

Folds on Europa: implications for crustal cycling and accommodation of extension.

PubMed

Prockter, L M; Pappalardo, R T

2000-08-11

Regional-scale undulations with associated small-scale secondary structures are inferred to be folds on Jupiter's moon Europa. Formation is consistent with stresses from tidal deformation, potentially triggering compressional instability of a region of locally high thermal gradient. Folds may compensate for extension elsewhere on Europa and then relax away over time.