carlos manuel villaba rivas - Academia.edu (original) (raw)

Papers by carlos manuel villaba rivas

2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces, 2007

At the contractor level once a product is required to be soldered with lead-free solders all the ... more At the contractor level once a product is required to be soldered with lead-free solders all the processes must be assessed as to insure the same quality a customer has been accustomed to with a Sn63Pb37 process is achieved. The reflow, wave soldering and hand assembly processes must all be optimized carefully to insure good joint formation as per the appropriate class of electronics with new solder alloys and often new fluxes. The selection of soldering materials and fluxes are important as to insure high quality solder joints with lead-free solders which tend to wet slower than leaded solders but also the process equipment must be lead-free process compatible. Components must be lead-free and able to meet the thermal requirements of the process but also the MSL (moisture sensitivity limits) must be observed. Board finish must be lead-free and the PCB must be able to sustain higher process temperature cycles with no physical damage but also good solderability to enable subsequent soldering at the wave or hand assembly.

Volume 12: Mechanics of Solids, Structures and Fluids, 2008

Soft tissue pathologies are often associated with changes in mechanical properties. For example, ... more Soft tissue pathologies are often associated with changes in mechanical properties. For example, breast and other tumors usually present as stiff lumps. Imaging the spatial distribution of the mechanical properties of tissues thus reveals information of diagnostic value. Doing so, however, typically requires the solution of an inverse elasticity problem. In this work we consider the inverse elasticity problem for an incompressible material in plane stress, formulated and solved as a constrained optimization problem. We formulate this inverse problem enforcing high order continuity for our variables. Driven by the requirements for the strong and weak solutions to this problem, we assume that our data field (i.e. the measured displacement) is in H2 and our parameter distribution (i.e. the sought shear modulus distribution) is in H1. This high order regularity requirement for the data is incompatible with standard FEM. We solve this problem using a FEM formulation that is novel in two ...

American Journal of Hypertension, 2002

To assess the importance of plasma semicarbazide-sensitive amine oxidase (SSAO) as a diagnostic t... more To assess the importance of plasma semicarbazide-sensitive amine oxidase (SSAO) as a diagnostic tool in chronic heart failure (CHF) with left ventricular systolic dysfunction. Design and Methods: Plasma SSAO was measured by an established functional assay in a non diabetic controlled hypertensive population of 50 patients with dilated cardiomyopathy in NYHA class III-IV and EF Յ 40%, measured by echocardiography biplane disc summation method (Simpson's rule) [mean ageϮSD) 67.4Ϯ11.1 years; female (F): 12 (24%); male (M): 38 (76%)] and 20 normal controls [mean age 54.5Ϯ13.7 years; F: 11 (55%); M: 9 (45%)]. Atrial natriuretic peptide (ANP) was measured with commercial IRMA kits. Endothelin-1 (ET-1) was measured by radioimmunoassay (RIA). To determine the relation between these variables a statistical analysis was done by Mann-Whitney-Wilcoxon test and Pearson's correlation. Results: In the patient population, the mean EF was 33Ϯ6.4% and in the controls was 61Ϯ3.4% (pϭ0.000). A statistically significant difference was found between patients and healthy controls. The mean SSAO (mU/l) was 608.4 Ϯ 271 in patients and 440.3Ϯ171in the healthy controls (pϭ0.003). The difference was also statistically significant. The mean ANP (pmol/l) in the patients was 32.4Ϯ20.9 and in the controls was 10.6Ϯ8.0(pϭ0.000). The mean ET-1 (pg/ml) in the patients was 4.6Ϯ2.6 and in the controls was 2.3Ϯ1.4 (pϭ 0.000). Plasma SSAO was correlated with ANP (rϭ0.27; pϭ0.05) and with ET-1 (rϭ0.48; pϭ0.000). Conclusions: Plasma SSAO was increased in a population of CHF with a mean EF of 33%, in NYHA class III and IV. A statistically significant difference was found between patients and healthy controls. A positive correlation was found between SSAO and ANP and ET-1. This amine oxidase is a useful tool for the diagnosis of CHF with LV systolic dysfunction.

American Journal of Hypertension, 2001

MAP curve. Thus, L-induced regional increases in SNA respond nonuniformly to baroreflex activatio... more MAP curve. Thus, L-induced regional increases in SNA respond nonuniformly to baroreflex activation. The increase in RSNA can be suppressed by baroreflex activation suggesting that the L-induced increase in RSNA subserves circulatory functions. In contrast, the increase in IBAT-SNA with L is not prevented by baroreflex activation suggesting the recruitment of sympathetic fibers that serve thermogenic or metabolic and not circulatory functions.

Heart, Lung and Circulation, 2015

At six months after treatment initiation, intravenous iron was associated with reduced severity o... more At six months after treatment initiation, intravenous iron was associated with reduced severity of the symptoms of chronic heart failure and improved renal function (both p<0.001 versus control). Also, ferritin and transferrin saturation levels were increased, as were haemoglobin levels, whereas inflammatory markers were reduced (all p<0.001 versus control). Left ventricular systolic and diastolic diameters were increased and improved left ventricular function correlated with iron status in patients receiving intravenous iron but not patients in the control group. Conclusions Intravenous iron treatment was associated with improved myocardial functional parameters and cardiac dimensions in patients with anaemia and chronic kidney disease.

Chemotherapy Research and Practice, 2014

Since anthracycline-induced cardiotoxicity (AIC), a complication of anthracycline-based chemother... more Since anthracycline-induced cardiotoxicity (AIC), a complication of anthracycline-based chemotherapies, is thought to involve iron, concerns exist about using iron for anaemia treatment in anthracycline-receiving cancer patients. This study evaluated how intravenous ferric carboxymaltose (FCM) modulates the influence of iron deficiency anaemia (IDA) and doxorubicin (3–5 mg per kg body weight [BW]) on oxidative/nitrosative stress, inflammation, and cardiorenal function in spontaneously hypertensive stroke-prone (SHR-SP) rats. FCM was given as repeated small or single total dose (15 mg iron per kg BW), either concurrent with or three days after doxorubicin. IDA (after dietary iron restriction) induced cardiac and renal oxidative stress (markers included malondialdehyde, catalase, Cu,Zn-superoxide dismutase, and glutathione peroxidase), nitrosative stress (inducible nitric oxide synthase and nitrotyrosine), inflammation (tumour necrosis factor-alpha and interleukin-6), and functional/m...

Toxic Substance Mechanisms, 1997

Abstract: Recent research on elucidation of mechanisms of the phototoxic activities of various ph... more Abstract: Recent research on elucidation of mechanisms of the phototoxic activities of various pharmaceutical products currently being investigated in this laboratory is reviewed. Due to the importance of antibacterial quinolones of com mon use in present m edical ...

Ultrasound in Medicine & Biology, 2010

Advanced radiation techniques such as intensity-modulated radiotherapy (IMRT) for complex geometr... more Advanced radiation techniques such as intensity-modulated radiotherapy (IMRT) for complex geometries in which targets are close to organs at risk have been introduced in radiation therapy, creating a need for procedures that allow easy three-dimensional (3-D) measurement of dose for verification purposes. Polymer gels that change their material properties when irradiated have been suggested for such use. For example, the change in their magnetic properties has been thoroughly investigated with magnetic resonance imaging (MRI). Also, we have previously shown that the mechanical stiffness, i.e., Young's modulus, of these gels changes with dose. This finding prompted us to assess whether we can image a radiation-induced stiffness distribution with quantitative ultrasound elastography and whether the stiffness distribution is correlated with the dose distribution. A methacrylic-acid-based gel was loaded with scatterers to create an ultrasound echoic signal. It was irradiated to create a rod-like region of increased stiffness with a 10 3 10 mm 2 cross-section. The gel block was compressed in a frame that restricted the movement of the gel to planes orthogonal to the long axis of the irradiated region and ultrasonic echo data were acquired in the central plane during compression. This simplified irradiation pattern and experimental setup were designed to approximate plane-strain conditions and was chosen for proof of concept. The movement of the gel was tracked from ultrasound images of a different compressional state using cross-correlation, enabling a displacement map to be created. The shear modulus was reconstructed using an inverse algorithm. The role of the magnitude of the regularization parameter in the inverse problem and the boundary conditions in influencing the spatial distribution of stiffness and, thus, final dose contrast was investigated through parametric studies. These parameters were adjusted using prior knowledge about the stiffness in parts of the material, e.g., the background was not irradiated and therefore its stiffness was homogeneous. It was observed that a suitable choice for these reconstruction parameters was essential for a quantitative application of stiffness measurement such as dosimetry. The dose contrast and distribution found with the optimal parameters were close to those obtained with MRI. Initial results reported in this article are encouraging and indicate that with ongoing refinement of ultrasound elastography techniques and accompanying inverse algorithms, this approach could play an important role in gel dosimetry.

Nephrology, 2008

Anaemia is prevalent in chronic kidney disease (CKD) and induces significant changes in heart and... more Anaemia is prevalent in chronic kidney disease (CKD) and induces significant changes in heart and kidney. In this study, we evaluated the relationship between iron metabolism, hepcidin and inflammation focusing on left ventricular (LV) function, in a remnant kidney rat model. Rats with 5/6 subtotal nephrectomy (STNx) and sham operation. Haemoglobin (Hb), serum iron (SI), fractional shortening (FS%) by echocardiograms were evaluated. Six months after STNx, the heart and kidney were processed by immunohistochemistry with antibodies against hypoxia-inducible factors (HIF)-1alpha, erythropoietin (EPO), pro-hepcidin, caspase-3, tumour necrosis factor (TNF)-alpha and interleukin (IL)-6. Hb (g/dL) STNx: 10.8 +/- 0.8, sham: 14.7 +/- 0.6 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01); SI (microg/dL) STNx: 154.5 +/- 24.5, sham: 287.5 +/- 32.1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01); heart weight (g) STNx: 2.21 +/- 0.15, sham: 1.12 +/- 0.12 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01); FS% STNx: 28.4 +/- 2.5, sham: 45.1 +/- 4.1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). There was a correlation between Hb and FS% (r = 0.95; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and between SI and FS% (r = 0.86; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) in the STNx group. Tissue ferritin was reduced in heart and in kidney in the STNx group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). HIF-1alpha was expressed in cardiomyocytes (positive cells/area) STNx:…

Revista Médica del …, 2007

Resumen Introducción: la bacteriología del líquido pleural (LP) para el diagnóstico de la tubercu... more Resumen Introducción: la bacteriología del líquido pleural (LP) para el diagnóstico de la tuberculosis pleural (TBP) es lenta y poco sensible; la biopsia de mejor rendimiento es cruenta y costosa. A pesar de que la dosificación de la adenosin deaminasa (ADA) en el ...

The Journal of the Acoustical Society of America, 2009

“Elastography” refers to the procedure of using ultrasound to image tissue deformation. Images sh... more “Elastography” refers to the procedure of using ultrasound to image tissue deformation. Images showing tissue deformation are sensitive to distributions of tissue mechanical properties. The mechanical properties themselves may be quantified by solving an inverse elasticity problem. An iterative approach to solving the inverse problem can be formulated by repeated solutions of the forward problem. That is, the shear modulus distribution sought is that which predicts a displacement field most consistent with the measured displacement field. Here we show that given plane displacement measurements for plane stress elasticity, the continuous elastic equilibrium equation uniquely determines the modulus distribution. On the other hand, we shall also demonstrate that the discrete elasticity equations from standard FEM discretization does not, even at the limit of infinite mesh refinement. We diagnose the problem as an underenforcement of the elasticity equations. With this knowledge, we have been able to design n...

Journal of Physics: Conference Series, 2009

Page 1. Imaging of dose distributions using polymer gels based on radiation induced changes in st... more Page 1. Imaging of dose distributions using polymer gels based on radiation induced changes in stiffness This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2009 J. Phys.: Conf. Ser. 164 012039 ...

Journal of Physics: Conference Series, 2008

Many inverse problems are formulated and solved as optimization problems. In this approach, the d... more Many inverse problems are formulated and solved as optimization problems. In this approach, the data mismatch between a predicted field and a measured field is minimized, subject to a constraint. The constraint represents the "forward" model of the system under consideration. In this paper, the model considered is plane stress incompressible elasticity. This pde is discretized using several standard Galerkin finite element methods. These are known to yield stable and convergent discrete solutions that converge with mesh refinement to the exact solution of the forward problem. It is usually taken for granted that if the constraint equation is discretized by a stable, convergent numerical method, then the inverse problem will also converge to the exact solution with mesh refinement. We show examples in this paper, however, where this is not the case. These are based on inverse problems with interior data, which have provably unique solutions. Even so, the use of classical discretization techniques for the forward constraint within the optimization formulation leads to ill-posed discrete problems. We analyze the discrete systems of equations and show the source of the instability. We discuss variational properties of the continuous inverse optimization problem, and describe a novel B-spline FEM to solve it. We present computational evidence that suggests the B-spline FEM inverse problem solution converges to the exact inverse problem solution with mesh refinement.

Journal of Medical Microbiology, 2008

The aim of this study was to determine the prevalence of Ser315Thr substitution in isoniazid (INH... more The aim of this study was to determine the prevalence of Ser315Thr substitution in isoniazid (INH)-resistant strains of Mycobacterium tuberculosis in Uruguay. The katG gene of 62 INH-resistant strains was analysed by an RFLP-PCR assay. PCR products were digested with MspI to detect Ser315Thr and Arg463Leu substitutions. A total of 16 of the 62 (26 %) INH-resistant strains analysed had a Ser315Thr substitution. Only one INH-resistant strain had an Arg463Leu substitution and two strains had a deletion in katG. Of the 16 strains with Ser315Thr, 15 showed different profiles using a double-repetitive-element PCR assay, demonstrating that there was no local dissemination of any particular strain. These findings are in agreement with published data from regions where the prevalence of tuberculosis (TB) is intermediate and may be due in part to the success of the local TB control programme.

Journal of Hypertension, 2003

Objective Obesity, non-insulin-dependent diabetes mellitus (NIDDM) and hypertension are leading c... more Objective Obesity, non-insulin-dependent diabetes mellitus (NIDDM) and hypertension are leading causes associated with increased cardiovascular morbidity and mortality. In modern times, the combined first line antihypertensive therapy with at least two drugs with a different mechanism of action to achieve a better blood pressure control, is increasing in acceptance worldwide. The aim of the present study was to determine possible beneficial effects of the low-dose combination (LDC) of an angiotensin-converting enzyme (ACE) inhibitor, perindopril (PER), and the diuretic indapamide (IND), regarding myocardial and vessels protection in an animal model of hypertension, obesity and NIDDM, such as the obese Zucker rat (OZR), and control lean Zucker rats (LZR). Design Ten-week-old male OZR (fa/fa) and LZR (Fa/fa) were used in this study. OZR group (G1, n 8), OZR with LDC group (G2, n 8); LZR group (G3, n 8) and LZR with LDC group (G4, n 8). During 6 months, G2 and G4 received a daily dose of 1 mg/kg combination of 0.76 mg/ kg PER + 0.24 mg/kg IND, (ratio of doses 0.32), by gavage, and G1 and G3 received an equal volume of vehicle throughout the experiment. In order to evaluate cardiac dimensions and left ventricular mass (LVM) transthoracic echocardiograms were performed, at baseline and at the end of the experiment. Urine and blood samples for biochemical determination were obtained. After 6 months of treatment all rats were sacrificed, hearts were harvested for light microscopy (LM), high-resolution light microscopy (HRLM), immunohistochemistry including monoclonal antibodies against transforming growth factor â (TGFâ 1) and anti-collagen type I (COL I) and type III (COL III) and electron microscopy (EM) studies. Results At the end of the study OZR treated with LDC presented: (1) lower blood pressure (128.9 6 4 versus 150.3 6 3.6 mmHg, P < 0.05); (2) smaller cardiac dimensions (P < 0.01); (3) lower LVM/100 g body weight (0.17 6 0.02 versus 0.30 6 0.05, P < 0.01); (4) higher fractional shortening (34.5 6 3.2 versus 23.3 6 5.9%, P < 0.01) than OZR untreated. Moreover, OZR that received LDC showed higher: (1) myocyte density (48 6 1.5 versus 20 6 2.5 myocytes/area, P < 0.01); (2) capillary density (30.5 6 3.1 versus 9.5 6 1.6 capillaries/area, P < 0.01); (3) myofilament thickness (12.05 6 0.27 versus 9.83 6 0.39 nm, P < 0.01); and lower amounts of: (1) TGFâ 1 in myocytes (P < 0.01), interstitium (P < 0.01) and vessel wall (P < 0.05); (2) COL I and COL III (P < 0.01), and COL I / COL III ratio (P < 0.01), compared with untreated OZR. Finally, OZR-treated with LDC showed not only unsubstantial modification in carbohydrate and lipid metabolism when compared with untreated OZR, but also an improvement in insulin/glucose ratio (P < 0.05). Conclusion These results suggest that LDC of PER + IND can control cardiovascular damage in OZR providing an additional help in the metabolic scenario likewise.

Journal of Hypertension, 2010

Background Although effective in reducing blood pressure, therapy with a first-generation b-block... more Background Although effective in reducing blood pressure, therapy with a first-generation b-blocker is currently controversial in metabolic syndrome due to its negative impact on carbohydrate and lipid metabolism. Objective and design We evaluated the effects of nebivolol, a third-generation highly selective b-blocker with additional vasodilating activity, versus the traditional b-blocker atenolol in controlling functional and morphological cardiovascular damage in a rat model of metabolic syndrome. Methods During 6 months, Zucker diabetic fatty (ZDF) rats and control lean Zucker rats (LZR) were studied. The experimental groups were: untreated ZDF, ZDF along with nebivolol, ZDF along with atenolol and LZR. Blood pressure, plasma insulin, triglycerides, cholesterol, glucose and platelet aggregation were evaluated. Malondialdehyde, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, CuZn superoxide dismutase, catalase and glutathione peroxidase were determined in heart homogenates and transforming growth factor b 1 and plasminogen activator inhibitor-1 (PAI-1) expression, by immunohistochemistry (IHC). Vascular reactivity, vascular cell adhesion molecule-1, platelet endothelial cell adhesion molecule-1, PAI-1, enhanced nitric oxide synthase and collagen expression were evaluated in aorta. Results Nebivolol and atenolol presented a similar reduction in blood pressure. However, nebivolol showed a better lipid profile, preserved left ventricular function, a significant control in left ventricular geometry and moderated left ventricular hypertrophy versus atenolol. Significant reduction in platelet aggregation and a substantial endothelium-dependent and endothelium-independent relaxation in vessels were also shown in the nebivolol group versus atenolol group. Antioxidant defenses were preserved by nebivolol with a reduction in oxidative stress parameters. Vascular cell adhesion molecule-1, platelet endothelial cell adhesion molecule-1, PAI-1 and eNOS were favorably modulated with nebivolol in vessel wall. TGFb 1 , PAI-1 and accumulation of collagen-III and collagen-I were also diminished in heart with nebivolol. Conclusion The present study provides substantial information supporting an actual protective role of nebivolol in comparison with atenolol in experimental metabolic syndrome.

Journal of Earthquake Engineering, 2007

The seismic vulnerability of housing stock in El Salvador was demonstrated during the recent 2001... more The seismic vulnerability of housing stock in El Salvador was demonstrated during the recent 2001 earthquakes. Relative to other types of common residential construction, confined masonry dwellings performed well. A coordinated pilot study was conducted with the objective of improving the seismic resistance of this form of construction while reducing associated costs and greenhouse gas emissions. Laboratory tests examined brick

Journal of Coordination Chemistry, 2003

International Journal for Numerical Methods in Engineering, 2009

We describe a novel variational formulation of inverse elasticity problems given interior data. T... more We describe a novel variational formulation of inverse elasticity problems given interior data. The class of problems considered is rather general and includes, as special cases, plane deformations, compressibility and incompressiblity in isotropic materials, 3D deformations, and anisotropy. The strong form of this problem is governed by equations of pure advective transport. The variational formulation is based on a generalization of the adjoint-weighted variational equation (AWE) formulation, originally developed for flow of a passive scalar. We describe how to apply AWE to various cases, and prove several properties. We prove that the Galerkin discretization of the AWE formulation leads to a stable, convergent numerical method, and prove optimal rates of convergence. The numerical examples demonstrate optimal convergence of the method with mesh refinement for multiple unknown material parameters, graceful performance in the presence of noise, and robust behavior of the method when the target solution is