Thrust control, stabilization and energetics of a quadruped running robot

In order to achieve powered autonomous running robots it is essential to develop efficient actuator systems, especially for generating the radial thrust in the legs. In addition, the control of the radial thrust of the legs can be a simple, effective method for stabilizing the body pitch in a running gait. This paper presents the mechanical systems, models and control strategies employed to generate and control leg thrust in the KOLT quadruped running robot. An analytical model of the electro-pneumatic leg thrusting system is presented and analyzed to evaluate its performance and to facilitate the design of control strategies. Several experiments have been conducted to estimate the energy losses and determine their origins as well as to compute the energetic efficiency of the actuation system. Two thrust control methods are also proposed and tested experimentally. The closed loop method regulates thrust through the control of the hip liftoff speed, a conceptually simple control strategy that stabilizes the body pitch in pronk and trot gaits without the need for central feedback, even on irregular terrain. The open-loop control method regulates the energy added in each hop based on the model of the actuator system. The efficacy of these models and techniques is tested in several planar trot and pronk experiments, and the results are analyzed focusing on the body stabilization, the power consumption and the energetic efficiency. © SAGE Publications 2008 Los Angeles

Ciencia sobre ruedas en Granada. Una experiencia de actualización científica y tecnológica en el aula

Describimos una experiencia de colaboración entre el Parque de las Ciencias de Granada y el centro educativo Ciencias sobre Ruedas de Puerto Rico para llevar a siete centros educativos de Andalucía la tecnología de experimentación asistida por ordenador, EXAO, conectándola con temas de investigación real en el área de química. El proceso comenzó con la formación del profesorado en el uso de esta tecnología dentro de un enfoque de enseñanza orientado hacia la investigación en el aula. La actividad ha estado a cargo de profesores universitarios de Puerto Rico que desarrollan actualmente sus investigaciones de doctorado. Se ofrece la experiencia como un modelo de actualización y formación del profesorado no universitario de ciencias

The volume of ERCP per endoscopist is associated with a higher technical success and a lower post-ERCP pancreatitis rate. A prospective analysis

Introduction: conflicting results have been reported regarding the influence of the annual volume of endoscopic retrograde cholangiopancreatography (ERCP) on outcome. Objective: to evaluate the influence of case volume on ERCP outcomes. Patients and methods: an analysis of a prospective database was performed, comparing the outcomes of ERCP in three consecutive periods defined by the number of endoscopists performing ERCP: five endoscopists in period I (P1), four in period II (P2) and three in period III (P3). Only patients with biliary ERCP in accessible and naïve papilla were included. Primary variables were cannulation rates and adverse effects (AE). The American Society of Gastrointestinal Endoscopy (ASGE) complexity grades III and IV were considered as highly complex procedures. Results: a total of 2,561 patients were included: 727 (P1), 972 (P2) and 862 (P3). There were no differences in age and sex between groups (p > 0.05). The cannulation rate was significantly higher in P2 and P3: 92.4 % vs 93.3 % vs 93 % (p = 0.037). The AE rate was 13.8 %, 12.6 % and 10.3 % (p > 0.05), respectively. The rate of post-ERCP pancreatitis was significantly lower in P3: 8.5 %, 7.3 % and 5 % (p = 0.01). The rate of complex procedures was 12 %, 14.8 % and 27 % (p < 0.0001), respectively. Two endoscopists participated in all periods and only one had significantly improved outcomes. Cannulation and post-ERCP pancreatitis rates remained significantly better in P3 after adjusting for sex, complexity and endoscopist. Conclusion: a higher annual volume of ERCP per endoscopist was associated with a higher rate of cannulation and a lower rate of post-ERCP pancreatitis, despite the greater complexity of the procedures. These beneficial effects seem to differ between endoscopists

Aging of ECG characteristics over a five year period

The aim of this work was to find evidence of aging of ECG indicators in a population of young adults (52 subjects of age 19 ± 0.6 in 2002). For this purpose, an application which analyzes ECG signals was designed and implemented. The data consist in four different series for each subject of the studied population. Two ECG signals of 5 minute duration (one at rest and one after a mild effort) were taken in 2002 and the exact same procedure was repeated for each subject five years later in 2007. All these electrocardiographic signals were examined by computational techniques in order to extract the RR and QT intervals and the energy content of the T-wave. Next, we have compared all the data using first return maps and measured the data dispersion by evaluating the covariance ellipses. Relations between each of the four data series were studied. The analysis also included the gender and the categorical aspect “practicing sport”

Methylated BSA Mimics Amyloid-Related Proteins and Triggers Inflammation

The mechanistic study of inflammatory or autoimmune diseases requires the generation of mouse models that reproduce the alterations in immune responses observed in patients. Methylated bovine serum albumin (mBSA) has been widely used to induce antigen-specific inflammation in targeted organs or in combination with single stranded DNA (ssDNA) to generate anti-nucleic acids antibodies in vivo. However, the mechanism by which this modified protein triggers inflammation is poorly understood. By analyzing the biochemical properties of mBSA, we found that mBSA exhibits features of an intermediate of protein misfolding pathway. mBSA readily interact with a list of dyes that have binding specificity towards amyloid fibrils. Intriguingly, mBSA displayed cytotoxic activity and its binding to ssDNA further enhanced formation of beta-sheet rich amyloid fibrils. Moreover, mBSA is recognized by the serum amyloid P, a protein unanimously associated with amyloid plaques in vivo. In macrophages, we observed that mBSA disrupted the lysosomal compartment, signaled along the NLRP3 inflammasome pathway, and activated caspase 1, which led to the production of IL-1β. In vivo, mBSA triggered rapid and prominent immune cell infiltration that is dependent on IL-1β induction. Taken together, these data demonstrate that by mimicking amyloidogenic proteins mBSA exhibits strong innate immune functions and serves as a potent adjuvant. These findings advance our understanding on the underlying mechanism of how aberrant immune responses lead to autoimmune reactions