320 research outputs found

    A Unique Test Bench for Various System-on-a-Chip

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    This paper discusses a standard flow on how an automated test bench environment which is randomized with constraints can verify a SOC efficiently for its functionality and coverage. Today, in the time of multimillion gate ASICs, reusable intellectual property (IP), and system-on-a-chip (SoC) designs, verification consumes about 70Ā % of the design effort. Automation means a machine completes a task autonomously, quicker and with predictable results. Automation requires standard processes with well-defined inputs and outputs. By using this efficient methodology it is possible to provide a general purpose automation solution for verification, given todayā€™s technology. Tools automating various portions of the verification process are being introduced. Here, we have Communication based SOC The content of the paper discusses about the methodology used to verify such a SOC-based environment. Cadence Efficient Verification Methodology libraries are explored for the solution of this problem. We can take this as a state of art approach in verifying SOC environments. The goal of this paper is to emphasize the unique testbench for different SOC using Efficient Verification Constructs implemented in system verilog for SOC verification

    Enhanced Genotoxicity of Silver Nanoparticles in DNA Repair Deficient Mammalian Cells

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    Silver nanoparticles (Ag-np) have been used in medicine and commercially due to their anti-microbial properties. Therapeutic potentials of these nanoparticles are being explored extensively despite the lack of information on their mechanism of action at molecular and cellular level. Here, we have investigated the DNA damage response and repair following Ag-np treatment in mammalian cells. Studies have shown that Ag-np exerts genotoxicity through double-strand breaks (DSBs). DNA-PKcs, the catalytic subunit of DNA dependent protein kinase, is an important caretaker of the genome which is known to be the main player mediating Non-homologous End-Joining (NHEJ) repair pathway. We hypothesize that DNA-PKcs is responsible for the repair of Ag-np induced DNA damage. In vitro studies have been carried out to investigate both cytotoxicity and genotoxicity induced by Ag-np in normal human cells, DNA-PKcs proficient, and deficient mammalian cells. Chemical inhibition of DNA-PKcs activity with NU7026, an ATP-competitive inhibitor of DNA-PKcs, has been performed to further validate the role of DNA-PKcs in this model. Our results suggest that Ag-np induced more prominent dose-dependent decrease in cell viability in DNA-PKcs deficient or inhibited cells. The deficiency or inhibition of DNA-PKcs renders the cells with higher susceptibility to DNA damage and genome instability which in turn contributed to greater cell cycle arrest/cell death. These findings support the fact that DNA-PKcs is involved in the repair of Ag-np induced genotoxicity and NHEJ repair pathway and DNA-PKcs particularly is activated to safeguard the genome upon Ag-np exposure

    Investigating the Toxicity of Iron(III) Oxide Nanoparticles, Zinc(II) Oxide Nanorods and Multi-Walled Carbon Nanotubes on Red Blood Cells

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    Abstract In recent years there has been much research into the use of nanomaterials in biological systems. Hemolysis of erythrocytes is a useful method to examine the effects of particles on the cell membrane. This study investigated the toxic effects of multi walled carbon nanotubes (MWCNT), zinc (II) oxide (ZnO) and iron(III) oxide (Fe 2 O 3 ) nanomaterials on human red blood cells (RBC). Cell morphology was studied before and after exposure to nanomaterials, using optical microscope, and AFM, which revealed distinct morphological aberrations. Ultra high resolution imaging systems were employed for studying the interaction of nanoparticles and RBC that unveiled attachment of nanoparticles to RBC and their cross linking effects. The hemolytic and hemagglutinating activities of these nanomaterials were investigated in detail. Our results showed that ZnO nanorods were able to induce hemolysis and hemagglutination in treated RBC whereas Fe 2 O 3 displayed only hemagglutination, and MWCNT showed only hemolysis. This study evidenced that MWCNT, ZnO and Fe 2 O 3 are toxic to human red blood cells irrespective of the blood group

    Molecular mechanisms of toxicity of silver nanoparticles in zebrafish embryos.

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    addresses: Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK. [email protected]: Journal Article; Research Support, Non-U.S. Gov'tThis is an open access article that is freely available in ORE or from the publisher's web site. http://pubs.acs.org/doi/abs/10.1021/es401758d. Please cite the published versionĀ© 2013 American Chemical SocietySupporting Information: Further details on the methodology and results for the characterization of the silver particles used for the exposures, mortality curves, sequencing analysis, and a number of supporting figures and tables. This material is available free of charge via the Internet at http://pubs.acs.org.Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms.Natural Environment Research Council (NERC)NERC Biomolecular Analysis FacilityUK Environment AgencySystems Biology Seed fund, University of Exete

    Exploring views and experiences of the general publicā€™s adoption of digital technologies for healthy lifestyle in Singapore: a qualitative study

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    ObjectiveLittle is known about the general adult populationā€™s adoption of digital technology to support healthy lifestyle, especially when they are expected to take greater personal responsibility for managing their health and well-being today. The current qualitative study intended to gain an in-depth understanding of determinants of digital technology adoption for healthy lifestyle among community-dwelling adults in Singapore.DesignA qualitative study design, with thematic framework analysis was applied to develop themes from the data.SettingSemi-structured individual interviews were conducted with participants either face-to-face or online through a videoconferencing platform.Participants14 women and 16 men from the general population who were between the ages of 22 and 71ā€‰years.ResultsThree major themes were developed: (1) digitally disempowered (2) safety and perceived risks and harm; (3) cultural values and drives. Adoption of technology among the general population is needs-driven, and contingent on individual, technological and other cross-cultural contextual factors.ConclusionOur findings highlight there is no one solution which fits all individuals, emphasizing the challenges of catering to diverse groups to reduce barriers to adoption of digital technologies for healthy lifestyle. Digital guidance and training, as well as social influences, can motivate technological adoption in the population. However, technical problems as well as data security and privacy concerns should first be adequately addressed. This study provides rich cross-cultural insights and informs policy-making due to its alignment with government public health initiatives to promote healthy lifestyle

    Study of Charge-Dependent Transport and Toxicity of Peptide-Functionalized Silver Nanoparticles Using Zebrafish Embryos and Single Nanoparticle Plasmonic Spectroscopy

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    Nanomaterials possess unusually high surface area-to-volume ratios and surface-determined physicochemical properties. It is essential to understand their surface-dependent toxicity in order to rationally design biocompatible nanomaterials for a wide variety of applications. In this study, we have functionalized the surfaces of silver nanoparticles (Ag NPs, 11.7 Ā±+2.7 nm in diameter) with three biocompatible peptides (CALNNK, CALNNS, CALNNE) to prepare positively (Ag-CALNNK NPs+Ī¶), negatively (Ag-CALNNS NPsāˆ’2Ī¶), and more negatively charged NPs (Ag-CALNNE NPsāˆ’4Ī¶), respectively. Each peptide differs in a single amino acid at its C-terminus, which minimizes the effects of peptide sequences and serves as a model molecule to create positive, neutral, and negative charges on the surface of the NPs at pH 4-10. We have studied their charge-dependent transport into early developing (cleavage-stage) zebrafish embryos and their effects on embryonic development using dark-field optical microscopy and spectroscopy (DFOMS). We found that all three Ag-peptide NPs passively diffused into the embryos via their chorionic pore canals, and stayed inside the embryos throughout their entire development (120 h), showing charge-independent diffusion modes and charge-dependent diffusion coefficients. Notably, the NPs create chargedependent toxic effects on embryonic development, showing that the Ag-CALNNK NPs+Ī¶ (positively charged) are the most biocompatible while the Ag-CALNNE NPsāˆ’4Ī¶ (more negatively charged) are the most toxic. By comparing with our previous studies of the same sized citrated Ag and Au NPs, the Ag-peptide NPs are much more biocompatible than the citrated Ag NPs, and nearly as biocompatible as the Au NPs, showing the dependence of nanotoxicity upon the surface charges, surface functional groups, and chemical compositions of the NPs. This study also demonstrates powerful applications of single NP plasmonic spectroscopy for quantitative analysis of single NPs in vivo and in tissues, and reveals the possibility of rational design of biocompatible NPs

    Engineered nanomaterials: toward effective safety management in research laboratories

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    It is still unknown which types of nanomaterials and associated doses represent an actual danger to humans and environment. Meanwhile, there is consensus on applying the precautionary principle to these novel materials until more information is available. To deal with the rapid evolution of research, including the fast turnover of collaborators, a user-friendly and easy-to-apply risk assessment tool offering adequate preventive and protective measures has to be provided.Results: Based on new information concerning the hazards of engineered nanomaterials, we improved a previously developed risk assessment tool by following a simple scheme to gain in efficiency. In the first step, using a logical decision tree, one of the three hazard levels, from H1 to H3, is assigned to the nanomaterial. Using a combination of decision trees and matrices, the second step links the hazard with the emission and exposure potential to assign one of the three nanorisk levels (Nano 3 highest risk; Nano 1 lowest risk) to the activity. These operations are repeated at each process step, leading to the laboratory classification. The third step provides detailed preventive and protective measures for the determined level of nanorisk.Conclusions: We developed an adapted simple and intuitive method for nanomaterial risk management in research laboratories. It allows classifying the nanoactivities into three levels, additionally proposing concrete preventive and protective measures and associated actions. This method is a valuable tool for all the participants in nanomaterial safety. The users experience an essential learning opportunity and increase their safety awareness. Laboratory managers have a reliable tool to obtain an overview of the operations involving nanomaterials in their laboratories; this is essential, as they are responsible for the employee safety, but are sometimes unaware of the works performed. Bringing this risk to a three-band scale (like other types of risks such as biological, radiation, chemical, etc.) facilitates the management for occupational health and safety specialists. Institutes and school managers can obtain the necessary information to implement an adequate safety management system. Having an easy-to-use tool enables a dialog between all these partners, whose semantic and priorities in terms of safety are often different

    In Vivo Quantitative Study of Sized-Dependent Transport and Toxicity of Single Silver Nanoparticles Using Zebrafish Embryos

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    Nanomaterials possess distinctive physicochemical properties (e.g., small sizes and high surface area-to-volume ratios) and promise a wide variety of applications, ranging from the design of high quality consumer products to effective disease diagnosis and therapy. These properties can lead to toxic effects, potentially hindering advances in nanotechnology. In this study, we have synthesized and characterized purified and stable (nonaggregation) silver nanoparticles (Ag NPs, 41.6 Ā± 9.1 nm in average diameter) and utilized early developing (cleavage-stage) zebrafish embryos (critical aquatic and eco- species) as in vivo model organisms to probe the diffusion and toxicity of Ag NPs. We found that single Ag NPs (30-72 nm diameters) passively diffused into the embryos through chorionic pores via random Brownian motion and stayed inside the embryos throughout their entire development (120 hours-post-fertilization, hpf). Dose-and size-dependent toxic effects of the NPs on embryonic development were observed, showing the possibility of tuning biocompatibility and toxicity of the NPs. At lower concentrations of the NPs (ā‰¤0.02 nM), 75-91% of embryos developed into normal zebrafish. At the higher concentrations of NPs (ā‰„0.20 nM), 100% of embryos became dead. At the concentrations in between (0.02-0.2 nM), embryos developed into various deformed zebrafish. Number and sizes of individual Ag NPs embedded in tissues of normal and deformed zebrafish at 120 hpf were quantitatively analyzed, showing deformed zebrafish with higher number of larger NPs than normal zebrafish and size-dependent nanotoxicity. By comparing with our previous studies of smaller Ag NPs (11.6 Ā± 3.5 nm), we found striking size-dependent nanotoxicity that, at the same molar concentration, the larger Ag NPs (41.6 Ā± 9.1 nm) are more toxic than the smaller Ag NPs (11.6 Ā± 3.5 nm)
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