Setting Procedure of a Robust Torsional Compensation Scheme Using a Shaft Angle Control Loop

Ricardo Leon,Guillermo Ramirez,Anibal Valenzuela 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In a related paper the authors developed a robust dynamic compensation scheme for high performance servo drives based on a shaft angle control loop. First, this paper establishes the physical relationship between the state feedback of load and motor speed and position differences and the proportional and derivative actions of the proposed control loop. Based on this relationship and a sensitivity analysis on the Bode diagram, a setting procedure for the controller gains is developed. Evaluation is done in a 2-mass servo drive model that includes the delays and quantization due to digital implementation, and a full-order observer of the unavailable signals.

Antifibrotic Effects of (ㅡ)-Epicatechin on High Glucose Stimulated Cardiac Fibroblasts

Alejandra Garate-Carrillo,Israel Ramirez-Sanchez,Justina Nguyen,Julisa Gonzalez,Guillermo Ceballos,Francisco Villarreal 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.11

Cardiac fibrosis is one of the hallmarks of a diabetic cardiomyopathy. When activated, cardiac fibroblasts (CFs) increase the production of extracellular matrix proteins. Transforming growth factor (TGF)-β1 is known to mediate cardiac fibrosis through the SMAD pathway. High glucose (HG = 25 mM) cell culture media can activate CFs using TGF-β1. There is a need to identify effective antifibrotic agents. Studies in animals indicate that treatment with (−)-epicatechin (Epi) appears capable of reducing myocardial fibrosis. Epi binds to G-protein coupled estrogen receptor (GPER) and activates downstream pathways. We evaluated the potential of Epi to mitigate the development of a profibrotic phenotype in HG stimulated CFs. CF primary cultures were isolated from young male rats and were exposed for up to 48 h HG media and treated with vehicle or 1 μM Epi. Relevant profibrotic end points were measured by the use of various biochemical assays. HG exposure of CFs increased TGF-β1 protein levels by ∼15%, fibronectin ∼25%, urea levels ∼60%, proline incorporation ∼70%, and total collagen ∼15%. Epi treatment was able to significantly block HG induced increases in TGF-β1, fibronectin, urea, proline, and total collagen protein levels. GPER levels were reduced by HG and restored in CFs treated with Epi an effect associated with the activation (i.e., phosphorylation) of c-Src. Epi treatment also reverted SMAD levels. Altogether, results demonstrate that CFs cultured in HG acquire a profibrotic phenotype, which is blocked by Epi an effect, likely mediated at least, in part, by GPER effects on the SMAD/TGF-β1 pathway.

Gastrointestinal stromal tumors as an incidental finding in patients with a presumptive diagnosis of ovarian cancer

Mario Muñoz,Pedro T. Ramirez,Carolina Echeverri,Luis Guillermo Álvarez,Maria Alejandra Palomino,Luis René Pareja,정준철 대한부인종양학회 2012 Journal of Gynecologic Oncology Vol.23 No.1

Objective: To report the clinical presentation and oncologic outcomes of a series of patients who presented with an abdominal or pelvic mass and were diagnosed with a gastrointestinal stromal tumor (GIST). Methods: Data were obtained on all patients who presented with an abdominal or pelvic mass between September 2007 and June 2010 and who were ultimately diagnosed with a GIST. The patients’ medical records were reviewed. A literature review was also conducted. Results: Six patients were identified who met the inclusion criteria. All six patients had a tumor in the intestinal tract arising from the small bowel. The mean tumor size was 12 cm (range, 6 to 22 cm). A complete resection was achieved in five of the six patients. There were no intraoperative complications; one patient had a postoperative complication. Two patients were treated with imatinib after surgery. The mean follow-up time was 32 months (range, 0.3 to 40 months). At the last follow-up, five of the six patients were without any evidence of disease. One patient died of an unrelated hepatic encephalopathy. The incidence in our institution is 3%. Conclusion: GISTs are uncommon; however, they should be considered in the differential diagnosis of patients presenting with an abdominal or pelvic mass. Objective: To report the clinical presentation and oncologic outcomes of a series of patients who presented with an abdominal or pelvic mass and were diagnosed with a gastrointestinal stromal tumor (GIST). Methods: Data were obtained on all patients who presented with an abdominal or pelvic mass between September 2007 and June 2010 and who were ultimately diagnosed with a GIST. The patients’ medical records were reviewed. A literature review was also conducted. Results: Six patients were identified who met the inclusion criteria. All six patients had a tumor in the intestinal tract arising from the small bowel. The mean tumor size was 12 cm (range, 6 to 22 cm). A complete resection was achieved in five of the six patients. There were no intraoperative complications; one patient had a postoperative complication. Two patients were treated with imatinib after surgery. The mean follow-up time was 32 months (range, 0.3 to 40 months). At the last follow-up, five of the six patients were without any evidence of disease. One patient died of an unrelated hepatic encephalopathy. The incidence in our institution is 3%. Conclusion: GISTs are uncommon; however, they should be considered in the differential diagnosis of patients presenting with an abdominal or pelvic mass.

(−)-Epicatechin Ameliorates Cardiac Fibrosis in a Female Rat Model of Pre-Heart Failure with Preserved Ejection Fraction

Moises Bustamante-Pozo,Israel Ramirez-Sanchez,Alejandra Garate-Carrillo,Bruce Ito,Viridiana Navarrete,Moises Haro,Ricardo Garcia,Nancy Carson,Guillermo Ceballos,Francisco Villarreal 한국식품영양과학회 2022 Journal of medicinal food Vol.25 No.8

One of the most abundant flavonoids present in cacao is (−)-epicatechin (Epi) and this flavanol has been linked to the cardiovascular health promoting actions of cocoa products. We previously demonstrated that Epi reduces infarct size in rodent models of ischemia/reperfusion and permanent coronary occlusion. Reduced infarct size was associated with decreased left ventricular (LV) oxidative stress (OS) and indicators of inflammation factors, which foster myocardial fibrosis. In this study, we examine the antifibrotic actions of Epi in an aging female rat model of pre-heart failure with preserved ejection fraction (pre-HFpEF) as well as its potential to mitigate plasma levels of OS, proinflammatory/profibrotic cytokines, and improve passive and active LV function. Epi treatment [1 mg/(kg·d)] was provided daily by gavage from 21 to 22 months of age, whereas controls received water. A Millar catheter was used to assess hemodynamic function. Subsequently, hearts were arrested in diastole, a balloon inserted into the LV and passive pressure–volume curves generated. Fixed LV sections were processed for collagen area fraction quantification using Sirius Red staining. Treatment with Epi did not lead to detectable changes in LV contractile function. However, passive LV pressure volume curves were significantly right shifted with Epi. Collagen area fraction values indicated that Epi treatment significantly reduces LV fibrosis. Epi also significantly reduced plasma OS markers and levels of profibrotic and proinflammatory cytokines. In conclusion, Epi reduces cardiac fibrosis in an aged, female rat model of pre-HFpEF, which correlates with significant reductions in OS and cytokine levels in the absence of changes in LV contractile function.

Impact of Agroforestry Plantings for Bioenergy Production on Soil Organic Carbon

Thomas Sauer,Yury Chendev,Guillermo Hernandez Ramirez,Alexsandr Petin,Richard Hall,Larisa Novyikh,Eugeniy Zazdravnyikh 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Effect of a Time Dependent Concrete Modulus of Elasticity on Prestress Losses in Bridge Girders

Brahama P. Singh,Nur Yazdani,Guillermo Ramirez 한국콘크리트학회 2013 International Journal of Concrete Structures and M Vol.7 No.3

Prestress losses assumed for bridge girder design and deflection analyses are dependent on the concrete modulus of elasticity (MOE). Most design specifications, such as the American Association of State Highways and Transportation Officials (AASHTO) bridge specifications, contain a constant value for the MOE based on the unit weight of concrete and the concrete compressive strength at 28 days. It has been shown in the past that that the concrete MOE varies with the age of concrete. The purpose of this study was to evaluate the effect of a time-dependent and variable MOE on the prestress losses assumed for bridge girder design. For this purpose, three different variable MOE models from the literature were investigated: Dischinger (Der Bauingenieur 47/48(20):563?572, 1939a; Der Bauingenieur 5/6(20):53?63, 1939b; Der Bauingenieur, 21/22(20):286?437, 1939c), American Concrete Institute (ACI) 209 (Tech. Rep. ACI 209R-92, 1992) and CEB-FIP (CEB-FIP Model Code, 2010). A typical bridge layout for the Dallas, Texas, USA, area was assumed herein. A prestressed concrete beam design and analysis program from the Texas Department of Transportation (TxDOT) was utilized to determine the prestress losses. The values of the time dependent MOE and also specific prestress losses from each model were compared. The MOE predictions based on the ACI and the CEB-FIP models were close to each other; in long-term, they approach the constant AASHTO value. Dischinger’s model provides for higher MOE values. The elastic shortening and the long term losses from the variable MOE models are lower than that using a constant MOE up to deck casting time. In long term, the variable MOE-based losses approach that from the constant MOE predictions. The Dischinger model would result in more conservative girder design while the ACI and the CEB-FIP models would result in designs more consistent with the AASHTO approach.

Anti-inflammatory and utero-relaxant effect of α-bisabolol on the pregnant human uterus

Munoz-Perez, Victor Manuel,Ortiz, Mario I.,Ponce-Monter, Hector A.,Monter-Perez, Vicente,Barragan-Ramirez, Guillermo The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.4

The aim of this study was to evaluate the in vitro anti-inflammatory and utero-relaxant effect of ${\alpha}$-bisabolol on the pregnant human myometrium. Samples from the pregnant human myometrium were used in functional tests to evaluate the inhibitory effect of ${\alpha}$-bisabolol (560, 860, 1,200 and $1,860{\mu}M$) on spontaneous myometrial contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to ${\alpha}$-bisabolol in human myometrial homogenates were measured by ELISA. The anti-inflammatory effect of ${\alpha}$-bisabolol was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-${\alpha}$ ($TNF{\alpha}$) and interleukin $(IL)-1{\beta}$, and the anti-inflammatory cytokine IL-10, in pregnant human myometrial explants stimulated with lipopolysaccharide (LPS). Forskolin was used as a positive control to evaluate the cAMP and cytokine levels. ${\alpha}$-Bisabolol was found to induce a significant inhibition of spontaneous myometrial contractions at the highest concentration level (p<0.05). ${\alpha}$-Bisabolol caused a concentration-dependent decrease in myometrial cAMP levels (p<0.05) and a concentration-dependent decrease in LPS-induced $TNF{\alpha}$ and $IL-1{\beta}$ production, while IL-10 production did not increase significantly (p>0.05). The anti-inflammatory and utero-relaxant effects induced by ${\alpha}$-bisabolol were not associated with an increase in cAMP levels in pregnant human myometrial samples. These properties place ${\alpha}$-bisabolol as a potentially safe and effective adjuvant agent in cases of preterm birth, an area of pharmacological treatment that requires urgent improvement.