1,040 research outputs found
DFT and BIST of a multichip module for high-energy physics experiments
Engineers at Politecnico di Torino designed a multichip module for high-energy physics experiments conducted on the Large Hadron Collider. An array of these MCMs handles multichannel data acquisition and signal processing. Testing the MCM from board to die level required a combination of DFT strategie
Medical Countermeasures for Radiation Induced Health Effects: Reports of an Interagency Panel Session Held at the NASA Human Research Program Investigator's Workshop, January 26, 2017
An Interagency Panel Session organized by the NASA Human Research Program Space Radiation Program Element (SRPE) was held during the NASA Human Research Program (HRP) Investigators Workshop (IWS) in Galveston, Texas on January 26, 2017 to identify complementary research areas that will advance the testing and development of medical countermeasures (MCM) in support of radioprotection and radiation mitigation on the ground and in space. There were several areas of common interest identified among the various participating agencies. This report provides a summary of the topics discussed by each agency along with potential areas of intersection for mutual collaboration opportunities. Common goals included repurposing of pharmaceuticals, neutraceuticals for use as radioprotectors and/or mitigators, low-dose/chronic exposure paradigms, late effects post-radiation exposure, mixed-field exposures of gamma-neutron, performance decrements, and methods to determine individual exposure levels
The X-shooter Spectral Library (XSL): I. DR1. Near-ultraviolet through optical spectra from the first year of the survey
We present the first release of XSL, the X-Shooter Spectral Library. This
release contains 237 stars spanning the wavelengths 3000--10200 \AA\ observed
at a resolving power . The spectra
were obtained at ESO's 8-m Very Large Telescope (VLT). The sample contains O --
M, long-period variable (LPV), C and S stars. The spectra are flux-calibrated
and telluric-corrected. We describe a new technique for the telluric
correction. The wavelength coverage, spectral resolution and spectral type of
this library make it well suited to stellar population synthesis of galaxies
and clusters, kinematical investigation of stellar systems and studying the
physics of cool stars.Comment: 41 pages, 38 figures, 5 tables. Accepted for publication in A&A.
Webpage: http://xsl.u-strasbg.fr
Reliability-Oriented Strategies for Multichip Module Based Mission Critical Industry Applications
The availability is defined as the portion of time the system remains operational to serve its purpose. In mission critical applications (MCA), the availability of power converters are determinant to ensure continue productivity and avoid financial losses. Multichip Modules (MCM) are widely adopted in such applications due to the high power density and reduced price; however, the high number of dies inside a compact package results in critical thermal deviations among them. Moreover, uneven power flow, inhomogeneous cooling and accumulated degradation, potentially result in thermal deviation among modules, thereby increasing the temperature differences and resulting in extra temperature in specific subset of devices. High temperatures influences multiple failure mechanisms in power modules, especially in highly dynamic load profiles. Therefore, the higher failure probability of the hottest dies drastically reduces the reliability of mission critical power converters. Therefore, this work investigate reliability-oriented solutions for the design and thermal management of MCM-based power converters applied in mission critical applications. The first contribution, is the integration of a die-level thermal and probabilistic analysis on the design for reliability (DFR) procedure, whereby the temperature and failure probability of each die are taken into account during the reliability modeling. It is demonstrated that the dielevel analysis can obtain more realistic system-level reliability of MCM-based power converters. Thereafter, three novel die-level thermal balancing strategies, based on a modified MCM - with more gate-emitter connections - are proposed and investigated. It is proven that the temperatures inside the MCM can be overcame, and the maximum temperate reduced in up to 8 %
The Backgrounds Data Center
The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible
Mini-chromosome maintenance complexes form a filament to remodel DNA structure and topology.
Deregulation of mini-chromosome maintenance (MCM) proteins is associated with genomic instability and cancer. MCM complexes are recruited to replication origins for genome duplication. Paradoxically, MCM proteins are in excess than the number of origins and are associated with chromatin regions away from the origins during G1 and S phases. Here, we report an unusually wide left-handed filament structure for an archaeal MCM, as determined by X-ray and electron microscopy. The crystal structure reveals that an α-helix bundle formed between two neighboring subunits plays a critical role in filament formation. The filament has a remarkably strong electro-positive surface spiraling along the inner filament channel for DNA binding. We show that this MCM filament binding to DNA causes dramatic DNA topology change. This newly identified function of MCM to change DNA topology may imply a wider functional role for MCM in DNA metabolisms beyond helicase function. Finally, using yeast genetics, we show that the inter-subunit interactions, important for MCM filament formation, play a role for cell growth and survival
Rational Design and Development of Purely Peptidic Amphiphiles for Gene Delivery
Gene therapy depends on viral and non-viral delivery systems to ferry nucleic acids into target cells 1,2. In recent years, gene insertion and interference therapies have made a ground breaking impact in the treatment of rare inherited diseases, neurological disorders, cardiac diseases, and cancer 3. Several disadvantages associated with viral vectors, such as high toxicity and immunogenicity, limitation in size of transgenic DNA, and high manufacturing cost have triggered the rapid expansion of non-viral delivery systems including peptide-based vectors 4. The advantages of peptides are not only their biocompatibility and biodegradability, but sheer limitless possible combinations and modifications of amino acid residues that are able to promote the assembly of modular, multiplexed delivery systems 5. With the advantages of peptides in mind, we looked into the potential of peptide-based nanoassemblies in developing a non-viral gene delivery system. The thesis is structured to successively address (i) the design and development of purely amphiphilic peptides self-assembling into multicompartment micelles (MCMs), (ii) the efficient DNA cargo entrapment up to 100 nucleotides in length into self-assembled peptide MCMs and the delivery thereof, and (iii) targeting of oligonucleotides to the nucleus via a nuclear localization signal (NLS) integrated in the peptide-based carrier. The challenge was to rationally design the peptides and identify the proper conditions in which the DNA entrapment does not interfere with multicompartment micellar self-assembly. In addition, to fulfil the prerequisites of a successful gene delivery system that overcomes cellular barriers, we incorporated biologically active amino acids in our peptide sequences. A systematic characterization of the physicochemical features of the peptidic nanostructures was carried out to gain insight into the mechanism underlying self-assembly and to shed light on ways to tune these features for prospective biomedical applications. Taking into account our findings on how the size/type of genetic payload together with the peptide amphiphile’s charge and length impact the self-assembly process, we successfully established a non-toxic, purely peptidic delivery system that serves as a cornerstone for developing oligonucleotide therapy platforms
Use data mining to improve student retention in HE - a case study
Data mining combines machine learning, statistics and visualization techniques to discover and extract knowledge. One of the biggest challenges that higher education faces is to improve student retention (National Audition Office, 2007). Student retention has become an indication of academic performance and enrolment management. Our project uses data mining and natural language processing technologies to monitor student, analyze student academic behaviour and provide a basis for efficient intervention strategies. Our aim is to identify potential problems as early as possible and to follow up with intervention options to enhance student retention. In this paper we discuss how data mining can help spot students ‘at risk’, evaluate the course or module suitability, and tailor the interventions to increase student retention
Using data mining to improve student retention in HE: a case study.
Data mining combines machine learning, statistics and visualization techniques to discover and extract knowledge. One of the biggest challenges that higher education faces is to improve student retention
(National Audition Office, 2007).
Student retention has become an indication of academic performance and enrolment management. Our project uses data mining and natural language processing technologies to monitor student, analyze student academic behaviour and provide a basis for efficient intervention strategies. Our aim is to identify potential problems as early as possible and to follow up with intervention options to enhance student retention. In this paper we discuss how data mining can help spot students ‘at risk’, evaluate the course or module suitability, and tailor the interventions to increase student retention
An investigation into minichromosomal maintenance proteins (MCMs) for the diagnosis of prostate cancer, as a possible alternative to prostate specific antigen (PSA)
The current strategy for the diagnosis of prostate cancer includes serum prostate specific antigen (PSA) measurement. There is however debate into its specificity and
sensitivity, so new diagnostic markers are under investigation. Minichromosomal
maintenance proteins (MCMs) are potential markers for the diagnosis of neoplasia, as
they are involved in cellular replication. The aim of this study is to assess MCM2, 5 and 7 as new diagnostic markers for prostate cancer, to compare the clinical usefulness of
PSA and to develop a less invasive technique for diagnosis.
PSA specificity was investigated in several human cellular lines, and a clinical study
was performed to assess expression in prostatic tissue and blood serum. MCM2, 5 and 7 was investigated by translational and transcriptional means in two prostate cell lines PNT1A and PC-3. In addition, a clinical study was performed to assess the expression of MCM2, 5 and 7 in prostate tissue, urine and blood
The results suggest that PSA is not prostate specific, as it is synthesised and secreted by several non-prostatic cell lines. In addition PSA testing does not conclusively indicate neoplastic tissue and serum testing only has 63% sensitivity and 60% specificity in accurately identifying prostate cancer. The in vitro results suggest that the PC-3 cells express less MCM2, 5 and 7 on both the protein and mRNA level compared to the
PNT1A cells, suggesting that MCM2, 5 and 7 maybe performing a bigger role than just
replication of DNA. The tissue results indicate that there is an increase in MCM2, 5
and 7 epithelial nuclei staining for neoplastic condition compared to BPH. While the clinical study on urine sediment indicates increased MCM2, 5 and 7 staining in prostatic neoplasia compared to BPH and the transcriptional study on MCM5 can identify neoplastic tissue from BPH as 11/12 cancerous patients expressed MCM5 compared to
only 3/23 BPH patients. Finally the transcriptional study on the blood samples is
inconclusive and need to be repeated
These results suggest that serum PSA testing is not ideal for the diagnosis of prostate
cancer, that MCM2, 5 and 7 appear to have potential as new diagnostic markers and
may aid the histopathologist to allocate Gleason score. Also the MCMs may have
potential in the development of a less invasive technique through the use of urine
sediment
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