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Control of peak floor accelerations of buildings under wind loads using tuned mass damper
Juan Acosta,Edén Bojórquez,Juan Bojórquez,Alfredo Reyes-Salazar,Omar Payán,Manuel Barraza,Juan Serrano 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.1
Due to the frequency and magnitude of some loads produced by gusts of turbulent wind, building floors can develop lateral displacements and significant accelerations which can produce strong inertial forces on structural, non-structural elements and occupants. A device that can help to reduce the floor accelerations is the well-known Tuned Mass Damper (TMD); however, nowadays there is no enough information about its capacity in order to dissipate energy of turbulent wind loads. For this reason, in this paper different buildings with and without TMD are modeled and dynamically analyzed under simulated wind loads in order to study the reduction of peak floor accelerations. The results indicate that peak floor accelerations can be reduced up to 40% when TMD are incorporated in the buildings, which demonstrated that the Tuned Mass Damper is an efficient device to reduce the wind effects on tall buildings.
Review of Acute Traumatic Closed Mallet Finger Injuries in Adults
Santiago Salazar Botero,Juan Jose Hidalgo Diaz,Anissa Benaïda,Sylvie Collon,Sybille Facca,Philippe André Liverneaux 대한성형외과학회 2016 Archives of Plastic Surgery Vol.43 No.2
In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana’s classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning.
Response transformation factors for deterministic-based and reliability-based seismic design
Edén Bojórquez,Juan Bojórquez,Sonia E. Ruiz,Alfredo Reyes-Salazar,Juan Velázquez-Dimas 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.6
One of the main requirements of the seismic design codes must be its easy application by structural engineers. The use of practically-applicable models or simplified models as single-degree-offreedom (SDOF) systems is a good alternative to achieve this condition. In this study, deterministic and probabilistic response transformation factors are obtained to evaluate the response in terms of maximum ductility and maximum interstory drifts of multi-degree-of-freedom (MDOF) systems based on the response of equivalent SDOF systems. For this aim, five steel frames designed with the Mexican City Building Code (MCBC) as well as their corresponding equivalent SDOF systems (which represent the characteristics of the frames) are analyzed. Both structural systems are subjected to ground motions records. For the MDOF and the simplified systems, incremental dynamic analyses IDAs are developed in first place, then, structural demand hazard curves are obtained. The ratio between the IDAs curves corresponding to the MDOF systems and the curves corresponding to the simplified models are used to obtain deterministic response transformation factors. On the other hand, demand hazard curves are used to calculate probabilistic response transformation factors. It was found that both approaches give place to similar results.
Seismic response of 3D steel buildings with hybrid connections: PRC and FRC
Alfredo Reyes-Salazar,Jesús Alberto Cervantes-Lugo,Arturo López-Barraza,Edén Bojórquez,Juan Bojorquez 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.1
The nonlinear seismic responses of steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are estimated, modeling the interior connections first as perfectly pinned (PPC), and then as partially restrained (PRC). Two 3D steel building models, twenty strong motions and three levels of the PRC rigidity, which are represented by the Richard Model and the Beam Line Theory, are considered. The RUAUMOKO Computer Program is used for the required time history nonlinear dynamic analysis. The responses can be significantly reduced when interior connections are considered as PRC, confirming what observed in experimental investigations. The reduction significantly varies with the strong motion, story, model, structural deformation, response parameter, and location of the structural element. The reduction is larger for global than for local response parameters; average reductions larger than 30% are observed for shears and displacements while they are about 20% for bending moments. The reduction is much larger for medium- than for low-rise buildings indicating a considerable influence of the structural complexity. It can be concluded that, the effect of the dissipated energy at PRC should not be neglected. Even for connections with relative small stiffness, which are usually idealized as PPC, the reduction can be significant. Thus, PRC can be used at IGF of steel buildings with PMRF to get more economical construction, to reduce the seismic response and to make steel building more seismic load tolerant. Much more research is needed to consider other aspects of the problem to reach more general conclusions.
Combined effect of the horizontal components of earthquakes for moment resisting steel frames
Alfredo Reyes-Salazar,José A. Juárez-Duarte,Arturo López-Barraza,Juan I. Velázquez-Dimas 국제구조공학회 2004 Steel and Composite Structures, An International J Vol.4 No.3
The commonly used seismic design procedures to evaluate the maximum effect of both horizontal components of earthquakes, namely, the Square Root of the Sum of the Squares (SRSS) and the 30- percent (30%) combination rules, are re-evaluated. The maximum seismic responses of four threedimensional moment resisting steel frames, in terms of the total base shear and the axial loads at interior, lateral and corner columns, are estimated as realistically as possible by simultaneously applying both horizontal components. Then, the abovementioned combination rules and others are evaluated. The numerical study indicates that both, the SRSS rule and the 30% combination method, may underestimate the combined effect. It is observed that the underestimation is more for the SRSS than for the 30% rule. In addition, the underestimation is more for inelastic analysis than for elastic analysis. The underestimation cannot be correlated with the height of the frames or the predominant period of the earthquakes. A basic probabilistic study is performed in order to estimate the accuracy of the 30% rule in the evaluation of the combined effect. Based on the results obtained in this study, it is concluded that the design requirements for the combined effect of the horizontal components, as outlined in some code-specified seismic design procedures, need to be modified. New combination ways are suggested.
Review of Acute Traumatic Closed Mallet Finger Injuries in Adults
Botero, Santiago Salazar,Diaz, Juan Jose Hidalgo,Benaida, Anissa,Collon, Sylvie,Facca, Sybille,Liverneaux, Philippe Andre Korean Society of Plastic and Reconstructive Surge 2016 Archives of Plastic Surgery Vol.43 No.2
In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana's classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning.
Nydia Ávila-Vanzzini,Juan Francisco Fritche-Salazar,Nelva Marina Vázquez-Castro,Pedro Rivera-Lara,Oscar Pérez-Méndez,Humberto Martínez-Herrera,Mario Gómez-Sánchez,Alberto Aranda-Frausto,Héctor Herrera 한국심초음파학회 2016 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.24 No.4
Background: Severe aortic stenosis (AS), leads to pathological left ventricular remodeling that may worsen with concomitantoverweight and obesity (OW/O). Methods: We aimed to prospectively analyze the impact of OW/O on ventricular remodeling in severe AS, by evaluating thepercentage of intraendomyocardial fibrosis (PIEF) and the percentage of infiltrating intraendocardial lipid vacuoles (PIELV) andits relationship to global longitudinal strain (GLS) in patients with OW/O. Results: 44 patients with severe AS were included, 13 non-obese (29%) and 31 OW/O (71%), all of them with left ventricularejection fraction ≥ 55%. GLS was evaluated with 2D speckle tracking. During valve replacement, an endocardial biopsy wasobtained, where PIEF and PIELV were analyzed. Patients with higher PIEF and PIELV had greater body mass index (p < 0.0001)and worse GLS (p < 0.0053). A GLS cut-off point < -14% had a sensitivity of 75%, and a specificity of 92.8% to detect importantPIEF (AUC: 0.928, 95% confidence interval: 0.798–1.00). On multivariate analysis, OW/O and PIELV were independentlyassociated to the PIEF, and OW/O and PIEF were independently associated to GLS. A high correlation between the amount ofPIELV and PIEF were found. Conclusion: Patients with severe AS and OW/O have greater PIEF and PIELV, suggesting more pathological remodeling. GLS is useful to detect subclinical myocardial injury and is potentially useful for endomyocardial fibrosis detection. The presenceof higher PIELF may be a trigger factor for the development of intraendomyocardial fibrosis.
Response transformation factors for deterministic-based and reliability-based seismic design
Bojorquez, Eden,Bojorquez, Juan,Ruiz, Sonia E.,Reyes-Salazar, Alfredo,Velazquez-Dimas, Juan Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.6
One of the main requirements of the seismic design codes must be its easy application by structural engineers. The use of practically-applicable models or simplified models as single-degree-of-freedom (SDOF) systems is a good alternative to achieve this condition. In this study, deterministic and probabilistic response transformation factors are obtained to evaluate the response in terms of maximum ductility and maximum interstory drifts of multi-degree-of-freedom (MDOF) systems based on the response of equivalent SDOF systems. For this aim, five steel frames designed with the Mexican City Building Code (MCBC) as well as their corresponding equivalent SDOF systems (which represent the characteristics of the frames) are analyzed. Both structural systems are subjected to ground motions records. For the MDOF and the simplified systems, incremental dynamic analyses IDAs are developed in first place, then, structural demand hazard curves are obtained. The ratio between the IDAs curves corresponding to the MDOF systems and the curves corresponding to the simplified models are used to obtain deterministic response transformation factors. On the other hand, demand hazard curves are used to calculate probabilistic response transformation factors. It was found that both approaches give place to similar results.
Luis D´Marco,Juan Salazar,Marie Cortez,María Salazar,Marjorie Wettel,Marcos Lima-Martínez,Edward Rojas,Willy Roque,Valmore Bermúdez 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.3
Background: Adipose tissue accumulation in specific body compartments has been associated with diabetes, hypertension and dyslipidemia. Perirenal fat (PRF) may lead to have direct lipotoxic effects on renal function and intrarenal hydrostatic pressure. This study was undertaken to explore the association of PRF with cardiovascular risk factors and different stages of chronic kidney disease (CKD). Methods: We studied 103 patients with CKD of different stages (1 to 5). PRF was measured by B-mode renal ultrasonography in the distal third between the cortex and the hepatic border and/or spleen. Results: The PRF thickness was greater in CKD patients with impaired fasting glucose than in those with normal glucose levels (1.10 ± 0.40 cm vs. 0.85 ± 0.39 cm, P < 0.01). Patients in CKD stages 4 and 5 (glomerular filtration rate [GFR] < 30 mL/min/1.73 m2) had the highest PRF thickness. Serum triglyceride levels correlated positively with the PRF thickness; the PRF thickness was greater in patients with triglyceride levels ≥ 150 mg/dL (1.09 ± 0.40 cm vs. 0.86 ± 0.36 cm, P < 0.01). In patients with a GFR < 60 mL/min/1.73 m2, uric acid levels correlated positively with the PRF thickness (P < 0.05). Conclusion: In CKD patients, the PRF thickness correlated significantly with metabolic risk factors that could affect kidney function.
Javier E. Jiménez-Salazar,Rene M. Rivera-Escobar,Rebeca Damián-Ferrara,Juan Maldonado-Cubas,Catalina Rincón-Pérez,Rosario Tarragó-Castellanos,Pablo Damián-Matsumura 한국유방암학회 2023 Journal of breast cancer Vol.26 No.5
Purpose: The epithelial-to-mesenchymal transition (EMT) is the main event that favors cell migration and metastasis in breast cancer. Previously, we demonstrated that 1 nM estradiol (E2) promotes EMT, induced by c-Src kinase, causing changes in the localization of proteins that compose the tight junction (TJ) and adherens junction (AJ). Methods: The present work highlights the central role of c-Src in the initiation of metastasis, induced by E2, through increasing the ability of MCF-7 and T47-D cells, which express estrogen receptor alpha (ERα), to migrate and invade before they become metastatic. Results: Treatment with E2 can activate two signaling pathways, the first one by the phosphorylated c-Src (p-Src) which forms the p-Src/E-cadherin complex. This phenomenon was completely prevented by incubation with a selective inhibitor of c-Src (5 μM PP2). p-Src then promotes the downregulation of E-cadherin and occludin, which are epithelial phenotype marker proteins of the AJ and TJ, respectively. In the second pathway, E2 binds to ERα, creating a complex that translocates to the nucleus, inducing the synthesis of SNAIL1 and N-cadherin proteins, markers of the mesenchymal phenotype. Both processes increased the migratory and invasive capacities of both cell lines. Conclusion: The present study demonstrate that E2 enhance EMT and migration, through c-Src activation, in human breast cancer cells that express ERα and become potential therapeutic targets.