1,902 research outputs found
Lab-Scale Circuit Breaker Module for Power System Laboratories
In this project, a circuit breaker that can simulate different types of power system faults is redesigned, constructed, and tested. They will then be implemented in power systems laboratory courses at Cal Poly. The project’s goal is to improve a previous circuit breaker design to help students better visualize how faults affect power systems in the real world. Two main improvements are made to the previous circuit breaker design. The first improvement is to power the breaker with a typical wall outlet adapter instead of the DC source from the Cal Poly power systems laboratory test benches. This lets the circuit breakers be used in settings other than at Cal Poly. This also reduces manufacturing costs for the circuit breaker to allow the Cal Poly EE department to afford more modules for increased student use. The adapter converts the AC wall voltage to a lower DC value than the test bench to allow for lower voltage ratings and thus lower costs of each component. The second improvement is to redesign the faceplate layout to appear more intuitive and linear by rearranging, connecting, or removing certain terminals. These changes allow students to more easily understand how current flows through the circuit breaker and makes wire setup and troubleshooting simpler. After the final circuit breaker was constructed, testing determined correct breaker functionality, and the circuit breaker can be replicated and used at reduced costs in future Cal Poly Electrical Engineering Labs
Nonthermal Bremsstrahlung and Hard X-ray Emission from Clusters of Galaxies
We have calculated nonthermal bremsstrahlung (NTB) models for the hard X-ray
(HXR) tails recently observed by BeppoSAX in clusters of galaxies. In these
models, the HXR emission is due to suprathermal electrons with energies of
about 10-200 keV. Under the assumption that the suprathermal electrons form
part of a continuous spectrum of electrons including highly relativistic
particles, we have calculated the inverse Compton (IC) extreme ultraviolet
(EUV), HXR, and radio synchrotron emission by the extensions of the same
populations. For accelerating electron models with power-law momentum spectra
(N[p] propto p^{- mu}) with mu <~ 2.7, which are those expected from strong
shock acceleration, the IC HXR emission exceeds that due to NTB. Thus, these
models are only of interest if the electron population is cut-off at some upper
energy <~1 GeV. Similarly, flat spectrum accelerating electron models produce
more radio synchrotron emission than is observed from clusters if the ICM
magnetic field is B >~ 1 muG. The cooling electron model produces vastly too
much EUV emission as compared to the observations of clusters. We have compared
these NTB models to the observed HXR tails in Coma and Abell 2199. The NTB
models require a nonthermal electron population which contains about 3% of the
number of electrons in the thermal ICM. If the suprathermal electron population
is cut-off at some energy above 100 keV, then the models can easily fit the
observed HXR fluxes and spectral indices in both clusters. For accelerating
electron models without a cutoff, the electron spectrum must be rather steep >~
2.9.Comment: Accepted for publication in the Astrophysical Journal. 10 pages with
5 embedded Postscript figures in emulateapj.sty. An abbreviated abstract
follow
Postexposure Treatment of Marburg Virus Infection
Rhesus monkeys are protected from disease when a recombinant vesicular stomatitis virus–based vaccine is administered 20–30 min after infection with Marburg virus. We protected 5/6 monkeys when this vaccine was given 24 h after challenge; 2/6 animals were protected when the vaccine was administered 48 h postinfection
Radar-cross-section reduction of wind turbines. part 1.
In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report
Automated eukaryotic gene structure annotation using EVidenceModeler and the Program to Assemble Spliced Alignments
EVidenceModeler (EVM) is an automated annotation tool that predicts protein-coding regions, alternatively spliced transcripts and untranslated regions of eukaryotic genes
Genome-Scale Model Reveals Metabolic Basis of Biomass Partitioning in a Model Diatom
Diatoms are eukaryotic microalgae that contain genes from various sources, including bacteria and the secondary endosymbiotic host. Due to this unique combination of genes, diatoms are taxonomically and functionally distinct from other algae and vascular plants and confer novel metabolic capabilities. Based on the genome annotation, we performed a genome-scale metabolic network reconstruction for the marine diatom Phaeodactylum tricornutum. Due to their endosymbiotic origin, diatoms possess a complex chloroplast structure which complicates the prediction of subcellular protein localization. Based on previous work we implemented a pipeline that exploits a series of bioinformatics tools to predict protein localization. The manually curated reconstructed metabolic network iLB1027_lipid accounts for 1,027 genes associated with 4,456 reactions and 2,172 metabolites distributed across six compartments. To constrain the genome-scale model, we determined the organism specific biomass composition in terms of lipids, carbohydrates, and proteins using Fourier transform infrared spectrometry. Our simulations indicate the presence of a yet unknown glutamine-ornithine shunt that could be used to transfer reducing equivalents generated by photosynthesis to the mitochondria. The model reflects the known biochemical composition of P. tricornutum in defined culture conditions and enables metabolic engineering strategies to improve the use of P. tricornutum for biotechnological applications
Design, assessment, and in vivo evaluation of a computational model illustrating the role of CAV1 in CD4+ T-lymphocytes
Caveolin-1 (CAV1) is a vital scaffold protein heterogeneously expressed in both healthy and malignant tissue. We focus on the role of CAV1 when overexpressed in T-cell leukemia. Previously, we have shown that CAV1 is involved in cell-to-cell communication, cellular proliferation, and immune synapse formation; however, the molecular mechanisms have not been elucidated. We hypothesize that the role of CAV1 in immune synapse formation contributes to immune regulation during leukemic progression, thereby warranting studies of the role of CAV1 in CD4+ T-cells in relation to antigen-presenting cells. To address this need, we developed a computational model of a CD4+ immune effector T-cell to mimic cellular dynamics and molecular signaling under healthy and immunocompromised conditions (i.e., leukemic conditions). Using the Cell Collective computational modeling software, the CD4+ T-cell model was constructed and simulated under CAV1+/+, CAV1+/−, and CAV1−/− conditions to produce a hypothetical immune response. This model allowed us to predict and examine the heterogeneous effects and mechanisms of CAV1 in silico. Experimental results indicate a signature of molecules involved in cellular proliferation, cell survival, and cytoskeletal rearrangement that were highly affected by CAV1 knock out. With this comprehensive model of a CD4+ T-cell, we then validated in vivo protein expression levels. Based on this study, we modeled a CD4+ T-cell, manipulated gene expression in immunocompromised versus competent settings, validated these manipulations in an in vivo murine model, and corroborated acute T-cell leukemia gene expression profiles in human beings. Moreover, we can model an immunocompetent versus an immunocompromised microenvironment to better understand how signaling is regulated in patients with leukemia
ACTION:a randomized phase 3 study of ONC201 (dordaviprone) in patients with newly diagnosed H3 K27M-mutant diffuse glioma
BACKGROUND: H3 K27M-mutant diffuse glioma primarily affects children and young adults, is associated with a poor prognosis, and no effective systemic therapy is currently available. ONC201 (dordaviprone) has previously demonstrated efficacy in patients with recurrent disease. This phase 3 trial evaluates ONC201 in patients with newly diagnosed H3 K27M-mutant glioma.METHODS: ACTION (NCT05580562) is a randomized, double-blind, placebo-controlled, parallel-group, international phase 3 study of ONC201 in newly diagnosed H3 K27M-mutant diffuse glioma. Patients who have completed standard frontline radiotherapy are randomized 1:1:1 to receive placebo, once-weekly dordaviprone, or twice-weekly dordaviprone on 2 consecutive days. Primary efficacy endpoints are overall survival (OS) and progression-free survival (PFS); PFS is assessed by response assessment in neuro-oncology high-grade glioma criteria (RANO-HGG) by blind independent central review. Secondary objectives include safety, additional efficacy endpoints, clinical benefit, and quality of life. Eligible patients have histologically confirmed H3 K27M-mutant diffuse glioma, a Karnofsky/Lansky performance status ≥70, and completed first-line radiotherapy. Eligibility is not restricted by age; however, patients must be ≥10 kg at time of randomization. Patients with a primary spinal tumor, diffuse intrinsic pontine glioma, leptomeningeal disease, or cerebrospinal fluid dissemination are not eligible. ACTION is currently enrolling in multiple international sites.</p
ACTION:a randomized phase 3 study of ONC201 (dordaviprone) in patients with newly diagnosed H3 K27M-mutant diffuse glioma
BACKGROUND: H3 K27M-mutant diffuse glioma primarily affects children and young adults, is associated with a poor prognosis, and no effective systemic therapy is currently available. ONC201 (dordaviprone) has previously demonstrated efficacy in patients with recurrent disease. This phase 3 trial evaluates ONC201 in patients with newly diagnosed H3 K27M-mutant glioma.METHODS: ACTION (NCT05580562) is a randomized, double-blind, placebo-controlled, parallel-group, international phase 3 study of ONC201 in newly diagnosed H3 K27M-mutant diffuse glioma. Patients who have completed standard frontline radiotherapy are randomized 1:1:1 to receive placebo, once-weekly dordaviprone, or twice-weekly dordaviprone on 2 consecutive days. Primary efficacy endpoints are overall survival (OS) and progression-free survival (PFS); PFS is assessed by response assessment in neuro-oncology high-grade glioma criteria (RANO-HGG) by blind independent central review. Secondary objectives include safety, additional efficacy endpoints, clinical benefit, and quality of life. Eligible patients have histologically confirmed H3 K27M-mutant diffuse glioma, a Karnofsky/Lansky performance status ≥70, and completed first-line radiotherapy. Eligibility is not restricted by age; however, patients must be ≥10 kg at time of randomization. Patients with a primary spinal tumor, diffuse intrinsic pontine glioma, leptomeningeal disease, or cerebrospinal fluid dissemination are not eligible. ACTION is currently enrolling in multiple international sites.</p
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