Search results for "Shock"
showing 10 items of 1248 documents
Mathematical Modeling and Optimization of a Vehicle Crash Test based on a Single-Mass
2014
In this paper mathematical modelling of a vehicle crash test based on a single mass is studied. The models under consideration consist of a single mass, a spring and/or a damper. They are constructed according to the measured vehicle speed before the collision and measured vehicle accelerations in three directions at the centre of gravity. A new model of nonlinear spring-mass-damper is also proposed to describe the crash. Simulation results are provided to show the effectiveness and applicability of the proposed methods.
Detailed characterization of laboratory magnetized super-critical collisionless shock and of the associated proton energization
2021
Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation. In the absence of particle collisions in the system, theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure (as in our case) is able to induce energy dissipation and allow shock formation. Shock formation can alternatively take place when two plasmas interact, through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation. Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers (JLF/Titan…
Capturing Shock Reflections: An Improved Flux Formula
1996
Godunov type schemes, based on exact or approximate solutions to the Riemann problem, have proven to be an excellent tool to compute approximate solutions to hyperbolic systems of conservation laws. However, there are many instances in which a particular scheme produces inappropriate results. In this paper we consider several situations in which Roe's scheme gives incorrect results (or blows up all together) and we propose an alternative flux formula that produces numerical approximations in which the pathological behavior is either eliminated or reduced to computationally acceptable levels.
Power ENO methods: a fifth-order accurate Weighted Power ENO method
2004
In this paper we introduce a new class of ENO reconstruction procedures, the Power ENO methods, to design high-order accurate shock capturing methods for hyperbolic conservation laws, based on an extended class of limiters, improving the behavior near discontinuities with respect to the classical ENO methods. Power ENO methods are defined as a correction of classical ENO methods [J. Comput. Phys. 71 (1987) 231], by applying the new limiters on second-order differences or higher. The new class of limiters includes as a particular case the minmod limiter and the harmonic limiter used for the design of the PHM methods [see SIAM J. Sci. Comput. 15 (1994) 892]. The main features of these new ENO…
2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ER…
2020
Guidelines summarize and evaluate available evidence with the aim of assisting health professionals in proposing the best management strategies for an individual patient with a given condition. Guidelines and their recommendations should facilitate decision making of health professionals in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.
Extracorporeal shock wave therapy as a potential therapeutic tool for breast cancer related lymphedema: a narrative review of in vitro, animal and cl…
2021
Background: The treatment of breast cancer related lymphedema (BCRL) focuses on the alleviation symptoms. One of the innovative, non-invasive therapies used for this condition is extracorporeal shock wave therapy (ESWT). Aim of the study: To review the available literature and evaluate the effectiveness of ESWT in the treatment of secondary lymphedema (in vitro works, animal experiments) and lymphedema associated with the treatment of breast cancer. Material and methods: The scientific literature review was conducted from October to December 2020. The review was carried out by searching scientifically recognized medical databases, including PubMed, MEDLINE and PEDro. Date restrictions were …
Chaperonology: The Third Eye on Brain Gliomas
2018
The European Organization for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial has validated as a current regimen for high-grade gliomas (HGG) a maximal safe surgical resection followed by radiotherapy with concurrent temozolamide. However, it is essential to balance maximal tumor resection with preservation of the patient&rsquo
The Streptomyces coelicolor dnaK operon contains a second promoter driving the expression of the negative regulator hspR at physiological temperature
2006
HspR (heat shock protein regulator) acts as a negative regulator of different genes in many bacteria. In Streptomyces coelicolor hspR gene is part and the transcriptional repressor of the dnaK operon which encodes the DnaK, GrpE, DnaJ chaperone machines and HspR itself. Our experiments led us to the discovery of a second promoter, internal to dnaK operon, located upstream hspR gene. Transcription from this promoter was detected at 30 degrees C indicating that hspR could play a key physiological role.
Characterization of the CtsR stress response regulon in Lactobacillus plantarum.
2010
ABSTRACT Lactobacillus plantarum ctsR was characterized. ctsR was found to be cotranscribed with clpC and induced in response to various abiotic stresses. ctsR deletion conferred a heat-sensitive phenotype with peculiar cell morphological features. The transcriptional pattern of putative CtsR regulon genes was examined in the Δ ctsR mutant. Direct CtsR-dependent regulation was demonstrated by DNA-binding assays using recombinant CtsR and the promoters of the ctsR - clpC operon and hsp1 .
Expression of a mutant HSP110 sensitizes colorectal cancer cells to chemotherapy and improves disease prognosis
2011
Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorou…