1,630 research outputs found
Assessment of Cell Viability Using the Chronoamperometric Method Based on Screen-Printed Electrodes
No full text[[abstract]]This study investigates suitable electrochemical mediators and optimal mediator concentration for breast cancer cells, MDA-MB-231. The optimized mediators were 1mM ferricyanide and 10 mu M menadione. The specifications for the chronoamperometric detection of ferrocyanide were a linear range of 0.020.36mM. The detection limit was 5.0 mu M and the spiked recovery was 95%99%. The oxidation currents increased linearly with cultured cell density. Cell viabilities determined using electrochemical methods confirmed those determined by MTT assay. The running time can be reduced to less than 30min. The chronoamperometric method can be used as an alternative method for rapidly assessing the viability of breast cancer cells.[[note]]SC
Effect of flaw state on the strength of brittle coatings on soft substrates
No full textA study is made of the role of flaw state on the strength properties of brittle ceramic coating layers bonded to soft polycarbonate substrates. We introduce Vickers radial cracks at prescribed loads into the coating undersurfaces prior to bonding to control the sizes and locations of the starting flaws. A spherical indenter is then loaded on the top bilayer surfaces, directly above the Vickers indentation sites, subjecting the radial cracks to flexural tensile stress. Radial crack responses are monitored in situ, using a camera located below the transparent substrate. Critical loads to cause radial crack instability, and ensuing growth of the arrested cracks, are recorded. Conventional biaxial flexure tests on corresponding monolith coating materials provide a baseline for data comparison. Relative to the monolith flexure specimens, the bilayers show higher strengths, the more so the larger the flaw, indicating enhanced flaw tolerance. A simple fracture mechanics analysis of the radial crack evolution in the concentrated-load field, with due account for distribution of flexural tensile stresses at the coating undersurface, is unable to account completely for the enhanced bilayer strengths for the larger Vickers flaws. It is hypothesized that the epoxy used to bond the bilayer components enters the cracks, causing crack-wall adherence and providing an increased resistance to radial crack instability. The fracture mechanics are nevertheless able to account for the arrest and subsequent stable extension of the radial cracks beyond the critical loads once this extraneous adherence has been overcome.The authors thank Herzl Chai for discussion
Gluon fusion and bb¯ corrections to HW+W−/HZZ production in the POWHEG-BOX
No full textAbstractThe study of the Higgs boson properties is one of the most important tasks to be accomplished in the next years, at the Large Hadron Collider (LHC) and at future colliders such as the Future Circular Collider in hadron–hadron mode (FCC-hh), the potential 100 TeV follow-up of the LHC machine. In this view the precise study of the Higgs couplings to weak gauge bosons is crucial and requires as much information as possible. After the recent calculation of the next-to-leading order QCD corrections to the production cross sections and differential distributions of a Standard Model Higgs boson in association with a pair of weak bosons, matched with parton shower in the POWHEG-BOX framework, we present the gluon fusion correction gg→HW+W−(HZZ) to the process pp→HW+W−(HZZ). This correction can be sizeable and amounts to +3% (+10%) in the HW+W− process and +5% (+18%) in the HZZ process at the LHC (FCC-hh). We also present the first study of the impact of the bottom-quark initiated channels bb¯→HW+W−/HZZ and find that they induce a significant +18% correction in the HW+W− channel at the FCC-hh. We present results on total cross sections and distributions at the LHC and at the FCC-hh
Inference of haplotypic phase and missing genotypes in polyploid organisms and variable copy number genomic regions
No full textBackground: The power of haplotype-based methods for association studies, identification of regions under selection, and ancestral inference, is well-established for diploid organisms. For polyploids, however, the difficulty of determining phase has limited such approaches. Polyploidy is common in plants and is also observed in animals. Partial polyploidy is sometimes observed in humans (e. g. trisomy 21; Down's syndrome), and it arises more frequently in some human tissues. Local changes in ploidy, known as copy number variations (CNV), arise throughout the genome. Here we present a method, implemented in the software polyHap, for the inference of haplotype phase and missing observations from polyploid genotypes. PolyHap allows each individual to have a different ploidy, but ploidy cannot vary over the genomic region analysed. It employs a hidden Markov model (HMM) and a sampling algorithm to infer haplotypes jointly in multiple individuals and to obtain a measure of uncertainty in its inferences.Results: In the simulation study, we combine real haplotype data to create artificial diploid, triploid, and tetraploid genotypes, and use these to demonstrate that polyHap performs well, in terms of both switch error rate in recovering phase and imputation error rate for missing genotypes. To our knowledge, there is no comparable software for phasing a large, densely genotyped region of chromosome from triploids and tetraploids, while for diploids we found polyHap to be more accurate than fastPhase. We also compare the results of polyHap to SATlotyper on an experimentally haplotyped tetraploid dataset of 12 SNPs, and show that polyHap is more accurate.Conclusion: With the availability of large SNP data in polyploids and CNV regions, we believe that polyHap, our proposed method for inferring haplotypic phase from genotype data, will be useful in enabling researchers analysing such data to exploit the power of haplotype-based analyses
Prevalence of CKD in 1534 subjects based on HW phenotype.
No full text<p>Prevalence of CKD in 1534 subjects based on HW phenotype.</p
Bacterial meningitis: the role of transforming growth factor-Beta in innate immunity and secondary brain damage
No full textProject 6 of the NCCR 'Neural Plasticity and Repair' focuses on mechanisms of immunity and tissue damage in autoimmune and infectious diseases of the central nervous system (CNS). In one of the subprojects, the influence of transforming growth factor-beta (TGF-beta) on the immune reactivity of the CNS was investigated. In mice with Streptococcus pneumoniae-induced meningitis, a deletion of TGF-beta receptor II on leukocytes is found to enhance recruitment of neutrophils to the site of infection and to promote bacterial clearance. The improved host defense against S. pneumoniae was associated with an almost complete prevention of meningitis-induced vasculitis, a major intracranial complication leading to brain damage. The data show that endogenous TGF-beta suppresses host defense against bacterial infection in the CNS. This contrasts with findings from other body compartments that suggested that TGF-beta is a powerful chemotactic cytokine and increases microbial clearance
KrakenOnMem: A Memristor-Augmented HW/SW Framework for Taxonomic Profiling
No full textState-of-the-art taxonomic profilers that comprise the first step in larger-context metagenomic studies have proven to be computationally intensive, i.e., while accurate, they come at the cost of high latency and energy consumption. Table Lookup operation is a primary bottleneck of today's profilers. In this paper, we first propose TL-PIM, a hardware accelerator based on the processing-in-memory (PIM) paradigm to accelerate Table Lookup. TL-PIM leverages the in-memory compute capability of emerging memory technologies along with intelligent data mapping. Then, we integrate TL-PIM into Kraken2, a state-of-the-art metagenomic profiler, and build an HW/SW co-designed profiler, called KrakenOnMem. Results from a silicon-based prototype of our emerging memory validate the design and required operations on a smaller scale. Our large-scale calibrated simulations show that KrakenOnMem can provide an average of 61.3% speedup compared to original Kraken2 for end-to-end profiling. Additionally, our design improves the energy consumption by orders of magnitude compared to the original Kraken2 while incurring a negligible area overhead. Computer EngineeringElectrical Engineering, Mathematics and Computer ScienceQuantum & Computer Engineerin
The Insulator Protein SU(HW) Fine-Tunes Nuclear Lamina Interactions of the Drosophila Genome
No full textSpecific interactions of the genome with the nuclear lamina (NL) are thought to assist chromosome folding inside the nucleus and to contribute to the regulation of gene expression. High-resolution mapping has recently identified hundreds of large, sharply defined lamina-associated domains (LADs) in the human genome, and suggested that the insulator protein CTCF may help to demarcate these domains. Here, we report the detailed structure of LADs in Drosophila cells, and investigate the putative roles of five insulator proteins in LAD organization. We found that the Drosophila genome is also organized in discrete LADs, which are about five times smaller than human LADs but contain on average a similar number of genes. Systematic comparison to new and published insulator binding maps shows that only SU(HW) binds preferentially at LAD borders and at specific positions inside LADs, while GAF, CTCF, BEAF-32 and DWG are mostly absent from these regions. By knockdown and overexpression studies we demonstrate that SU(HW) weakens genome – NL interactions through a local antagonistic effect, but we did not obtain evidence that it is essential for border formation. Our results provide insights into the evolution of LAD organization and identify SU(HW) as a fine-tuner of genome – NL interactions.BiotechnologyApplied Science
Understanding a time reversal process in Lamb wave propagation
No full textThis study investigates the time reversal process (TRP) of Lamb wave signals which are transmitted and received by piezoelectric transducers bonded on plate-like structures. A number of previous studies have paid attention to spatial and temporal refocusing capability of an original excitation through the TRP in highly dispersive and complex media. However, when the TRP is applied to Lamb waves in a homogeneous regular waveguide, the refocusing capability is limited due to permanent residual side bands even if the duration of the time reversed signal increases. Based on the reciprocity of elastodynamics and linear piezoelectricity, theoretical interpretation is conducted for the main and residual side bands of the reconstructed signal in the time domain. In particular, the interpretation includes the temporal effect of velocity and amplitude dispersions, the existence of multi-modes, and the reflections from boundaries during the TRP. Then, numerical and experimental tests are conducted to validate the theoretical findings of this paper. Practical issues for the successful implementation of the TRP of Lamb waves are briefly addressed as well. (C) 2009 Elsevier B.V. All rights reserved.This work was supported by Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research
Promotion Fund) (KRF-2008-331-D00590), in which main calculations were performed by using the supercomputing
resource of the Korea Institute of Science and Technology Information (KISTI), and the Radiation Technology Program under
Korea Science and Engineering Foundation (KOSEF) and the Ministry of Science and Technology (M20703000015-07N0300-
01510). The second author would like to acknowledge the graduate fellowship program from Samsung Scholarship in Seoul,
Korea
Wave-front Behaviour of the Pulsed EM Field – Complexity and Implications
No full textThe pulsed electromagnetic (EM) field radiated by a gap-fed, long slot in a perfectly conducting thin sheet located in between dielectric and free-space subdomains is examined. A phenomenological interpretation of the so-called head wave (HW) constituent is proposed, this fostering the understanding of the complex EM behaviour at, and immediately behind, the HW wave-front. The EM field is also examined numerically for identifying features that may lead the way towards inferring a causal counterpart of the leaky-wave propagation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz SensingElectrical Engineering Educatio
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