Energy harvesting from train vibrations

In this paper, linear mechanical oscillators are designed to harvest energy from train-induced vibrations. The harvested energy could be used, for example, to charge sensors mounted on the rail track for structural health monitoring. The dominant frequencies due to a passing train are determined for a specific train and speed from a recorded acceleration time-history. Using a simple model of an oscillator, the total energy harvested for the passage of one train is calculated. The stiffness, and hence the tuning frequency of the device, is varied in simulations to determine the optimum frequency at which to tune the device for a constant value of mass and damping in the device. Further simulations are conducted to investigate the power that could be harvested from multiple oscillators tuned at several dominant frequencies, and their performances are analysed and compared. The constraint for maximum relative displacement is considered in the design of each harvester, and this is adopted to assure that the amplitude of the oscillation is finite and does not exceed the physical size of the device. The robustness of the harvester is also analysed for different train speeds

Learning Inverse Kinodynamics for Autonomous Vehicle Drifting

In this work, we explore a data-driven learning-based approach to learning the kinodynamic model of a small autonomous vehicle, and observe the effect it has on motion planning, specifically autonomous drifting. When executing a motion plan in the real world, there are numerous causes for error, and what is planned is often not what is executed on the actual car. Learning a kinodynamic planner based off of inertial measurements and executed commands can help us learn the world state. In our case, we look towards the realm of drifting; it is a complex maneuver that requires a smooth enough surface, high enough speed, and a drastic change in velocity. We attempt to learn the kinodynamic model for these drifting maneuvers, and attempt to tighten the slip of the car. Our approach is able to learn a kinodynamic model for high-speed circular navigation, and is able to avoid obstacles on an autonomous drift at high speed by correcting an executed curvature for loose drifts. We seek to adjust our kinodynamic model for success in tighter drifts in future work

Normal crossings degenerations of symplectic manifolds

We use local Hamiltonian torus actions to degenerate a symplectic manifold to a normal crossings symplectic variety in a smooth one-parameter family. This construction, motivated in part by the Gross-Siebert and B. Parker's programs, contains a multifold version of the usual (two-fold) symplectic cut construction and in particular splits a symplectic manifold into several symplectic manifolds containing normal crossings symplectic divisors with shared irreducible components in one step

Increased expression of two alternative spliced variants of CD1d molecule in human gastric cancer

Background: CD1d presents glycolipid antigens to invariant natural killer T (iNKT) cells. The role of CD1d in the development of peptic ulcer and gastric cancer has not been revealed, yet. Objective: To clarify the expression of alternatively spliced variants of CD1d in peptic ulcer and gastric cancer. Methods: Patients with dyspepsia were selected and divided into three groups of non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), and gastric cancer (GC), according to their endoscopic and histopathological examinations. H. pylori infection was diagnosed by rapid urease test and histopathology. The expression levels of V2, V4, and V5 spliced variants of CD1d molecule were determined by quantitative Reverse Transcriptase PCR. Results: Relative gene expression levels of V4 were higher in GC patients (n=37) than those in NUD (n=49) and PUD (n=51) groups (p<0.05 and p<0.01, respectively). Moreover, GC patients showed higher expression levels of V5 compared to NUD and PUD groups (p<0.001 and p<0.001, respectively). Positive correlation coefficients were attained between V4 and V5 expression in patients with PUD (r=0.734, p<0.0001) and GC (r=0.423, p<0.01), but not in patients with NUD. Among NUD patients, the expression levels of V4, but not V5, were higher in H. pylori-positive patients than in H. pylori-negative ones (p<0.01). Conclusion: Collectively, both membrane-bound (V4) and soluble (V5) isoforms of CD1d were over-expressed in gastric tumor tissues, suggesting that they are involved in anti-tumor immune responses. © 2015, Shiraz University of Medical Sciences. All rights reserved

Expression levels of vascular endothelial growth factors A and C in patients with peptic ulcers and gastric cancer

Purpose: Vascular endothelial growth factor (VEGF) is one of the most important growth factors for metastatic tumors. To clarify the role of VEGF-A and C in patients with peptic ulcer disease (PUD) or gastric cancer (GC), we evaluated the expression levels of these two molecules. We also analyzed the effect of Helicobacter pylori infection on VEGF-A and C expression levels

Unsuspected Tracheal Web with Asthma-Like Symptom in a Young Female: Case Report

Background: Although most patients with asthma are easily controlled with appropriate medication, a small proportion of patients (approximately 5% of asthmatics) are difficult to control despite maximal inhaled therapy.Case Report: A 20-year-old girl admitted to the emergency ward (EW) of loghman hakim hospital in tehran with severe dyspnea. She was born with asphyxia for which oxygen therapy prescribed for two days.  Conclusion: Congenital abnormality of the trachea can rarely present as asthma symptoms in adulthood. It is important to know, when encounter too difficult to treat asthma as the condition can be curable surgically