Analytic Model for Quadruped Locomotion Task-Space Planning

Despite the extensive presence of the legged locomotion in animals, it is extremely challenging to be reproduced with robots. Legged locomotion is an dynamic task which benefits from a planning that takes advantage of the gravitational pull on the system. However, the computational cost of such optimization rapidly increases with the complexity of kinematic structures, rendering impossible real-time deployment in unstructured environments. This paper proposes a simplified method that can generate desired centre of mass and feet trajectory for quadrupeds. The model describes a quadruped as two bipeds connected via their centres of mass, and it is based on the extension of an algebraic bipedal model that uses the topology of the gravitational attractor to describe bipedal locomotion strategies. The results show that the model generates trajectories that agrees with previous studies. The model will be deployed in the future as seed solution for whole-body trajectory optimization in the attempt to reduce the computational cost and obtain real-time planning of complex action in challenging environments.Comment: Accepted to be Published in 2019, 41th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Berlin German

Community-acquired Pneumonia Owing to Multidrug-Resistant Pathogens: A Step toward an Early Identification

N

Nivolumab plus Ipilimumab in Non-Small-Cell Lung Cancer

To the Editor: Although more than 10% of the patients in the CheckMate 227 trial conducted by Hellmann et al. (Nov. 21 issue)(1) had never smoked, the effect of smoking status on survival was not fully discussed. Striking differences in the clinical and molecular characteristics of lung cancers between smokers and those who have never smoked have been identified, suggesting that the cancers are separate entities.(2) In one trial,(3) patients who had never smoked had poorer responses to nivolumab (as compared with docetaxel) than current or former smokers (hazard ratio for overall survival, 1.02 vs. 0.70). In a meta-analysis involving . .

Adding PD-1/PD-L1 inhibitors to chemotherapy for the first-line treatment of extensive stage small cell lung cancer (Sclc): A meta-analysis of randomized trials

Survival outcomes in extensive-stage small cell lung cancer (ES SCLC) are dismal, with median overall survival (OS) less than 12 months. The combination of PD-1/PD-L1 immune checkpoint inhibitors (ICIs) with first-line platinum-etoposide chemotherapy has been recently evaluated in randomized clinical trials. We performed a systematic literature review through PubMed and conference proceedings. Randomized trials evaluating chemotherapy +/− PD-1/PD-L1 ICIs were included in the meta-analysis. Efficacy (OS), activity [progression-free survival (PFS) and objective response rate (ORR)] outcomes and toxicities were analyzed. For selected endpoints, we focused on patients’ subgroups (OS) and on landmark analyses (OS, PFS). Four randomized trials were identified; globally, 1553 patients were randomized to receive chemotherapy +/− PD-1/PD-L1 ICIs. Adding a PD-1/PD-L1 ICI to chemotherapy led to a significant benefit in OS [hazard ratio (HR) 0.76, 95% confidence interval (CI) 0.68–0.85, p < 0.00001), PFS [HR 0.75, 95% CI 0.68–0.84, p < 0.00001] and ORR [odds ratio 1.28, 95% CI 1.04–1.57, p = 0.02]. No unexpected toxicity emerged. At 12, 18, 24 months for OS, and at 12, 18 months for PFS, experimental arms retained significant improvement in event-free rates, with absolute gain of approximately 10% compared with standard treatment. Albeit the magnitude of the benefit is less impacting compared to other settings of immunotherapy, the addition of PD-1/PD-L1 ICIs to chemotherapy in ES SCLC provided significant improvements in survival outcomes with the known toxicity profile. Biomarkers predicting which patients are suitable to derive long-term benefits are eagerly awaited

Motor Control Insights on Walking Planner and its Stability

The application of biomechanic and motor control models in the control of bidedal robots (humanoids, and exoskeletons) has revealed limitations of our understanding of human locomotion. A recently proposed model uses the potential energy for bipedal structures to model the bipedal dynamics, and it allows to predict the system dynamics from its kinematics. This work proposes a task-space planner for human-like straight locomotion that target application of in rehabilitation robotics and computational neuroscience. The proposed architecture is based on the potential energy model and employs locomotor strategies from human data as a reference for human behaviour. The model generates Centre of Mass (CoM) trajectories, foot swing trajectories and the Base of Support (BoS) over time. The data show that the proposed architecture can generate behaviour in line with human walking strategies for both the CoM and the foot swing. Despite the CoM vertical trajectory being not as smooth as a human trajectory, yet the proposed model significantly reduces the error in the estimation of the CoM vertical trajectory compared to the inverted pendulum models. The proposed model is also able to asses the stability based on the body kinematics embedding in currently used in the clinical practice. However, the model also implies a shift in the interpretation of the spatiotemporal parameters of the gait, which are now determined by the conditions for the equilibrium and not \textit{vice versa}. In other words, locomotion is a dynamic reaching where the motor primitives are also determined by gravity

Varicocele in the adolescent population: challenges in management

O manejo da varicocele em adolescentes continua sendo um dos tópicos mais interessantes e debatidos. Embora a crescente conscientização do comprometimento testicular induzido por varicocele tenha motivado diversos estudos, algumas das controvérsias na varicocele em adultos, em relação à fisiopatologia, tratamento e problemas de fertilidade, também podem ser transpostas para a população adolescente. Além disso, os adolescentes representam um grupo heterogêneo com desafios no diagnóstico, parâmetros clínicos e preditores de desfecho limitados. O desenvolvimento físico e puberal reflete-se em dificuldades para condutas padronizadas. O objetivo deste artigo é revisar os dados disponíveis da literatura sobre a apresentação, epidemiologia e patogênese da varicocele em crianças e adolescentes. Também abordamos as principais limitações e desafios da avaliação clínica e fornecemos evidências atuais sobre o dilema do tratamento com varicocele nesse subconjunto específico de pacientes. Opções de intervenção e resultados também são discutidos. A presente revisão baseia-se em uma busca eletrônica utilizando as bases de dados Pubmed / MEDLINE e referências dos artigos identificados realizadas entre março e maio de 2018.Management of varicoceles in adolescents remain one of the most interesting and debatable topics. Although the crescent awareness of varicocele-induced testicular impairment has motivated several studies, some of the controversies in adult varicocele, regarding pathophysiology, treatment and fertility issues can also be transposed the adolescent population. Furthermore, adolescents represent a heterogenic group with challenges in diagnosis, clinical parameters, and limited predictors. Physical and pubertal development reflects in difficulties for standard management. The purpose of this article is to review available data from literature regarding the presentation, epidemiology and pathogenesis of varicocele in children and adolescents. We also address major limitations and challenges of clinical evaluation and provide current evidence regarding the dilemma of varicocele treatment in this particular subset of patients. Interventions options and outcomes are also discussed. The current review is based on an electronic search using Pubmed/MEDLINE databases and references of the identified articles performed between March and May of 2018