71 research outputs found

    MULTI-OBJECTIVE DESIGN AUTOMATION FOR RECONFIGURABLE MULTI-PROCESSOR SYSTEMS

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    Ph.DDOCTOR OF PHILOSOPH

    Effect of Element Addition and Heat Treatment Process on the Properties of High Manganese Steel

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    The changing of properties of HMnS by alloy elements addition and heat treatment was presented. Studying about the hardness of HMnS were increased when the Mn contents increased. On the other hand, the Cr content has effective on the hardness and microstructure of this steel also, but with the Cr content was increased from 2% to 2,5%, the hardness of high Manganese steel was not much changed. With the research about HMnS, it was added the Cr and applied the advanced heat treatment process, the microstructure of this steel was formed the chrome carbide particles with grain fine which dispersed in the matrix with the formation of these dispersed carbide particles will contribute to increasing the alloy's abrasion resistance. With the difference in heat treatment processes, the microstructure and hardness were also changed. When the sample was heat-treated according to the model heat treating; the particle size of the sample is also significantly reduced. This explains why the hardness value of the sample increases significantly. Also, under the impact load, on the surface layer of this steel, the microstructure does not appear the martensite structure form but only see the twinning on the surface. These are new findings on the mechanism transformation of high manganese austenite steel when working under the impact of the impact force. The mechanism of transformation is quite different from the previous view of phase transformation under the impact force of high manganese austenitic steel

    Multifunctional nanocarriers of Fe3O4@PLA-PEG/curcumin for MRI, magnetic hyperthermia and drug delivery

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    Background: Despite medicinal advances, cancer is still a big problem requiring better diagnostic and treatment tools. Magnetic nanoparticle (MNP)-based nanosystems for multiple-purpose applications were developed for these unmet needs. Methods: This study fabricated novel trifunctional MNPs of Fe3O4@PLA-PEG for drug release, MRI and magnetic fluid hyperthermia. Result: The MNPs provided a significant loading of curcumin (∼11%) with controllable release ability, a high specific absorption rate of 82.2 W/g and significantly increased transverse relaxivity (r2 = 364.75 mM-1 s-1). The in vivo study confirmed that the MNPs enhanced MRI contrast in tumor observation and low-field magnetic fluid hyperthermia could effectively reduce the tumor size in mice bearing sarcoma 180. Conclusion: The nanocarrier has potential for drug release, cancer treatment monitoring and therapy.The authors are grateful for the financial support by AOARD under award FA2386-17-1-4042. The Spanish government is acknowledged for the “Nanotechnology in translational hyperthermia (HIPERNANO)” research network (RED2018102626-T) and for funding under the project number MAT2017-83631-C3. NTK Thanh thanks EPSRC (EP/M015157/1). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed

    The effect of different media and temperature conditions for Salmonella bacteriophage preservation

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    This research aimed to determine the optimal media and temperature conditions for the long-term storage of bacteriophages. In this study, the viability of Salmonella phages in 50% glycerol, 10% sodium chloride-magnesium sulfate (SM) buffer, and 5% dimethyl sulfoxide (DMSO) media at room temperature, 4oC, -20oC, and -80oC for 12 months was determined. In 50% glycerol, at the end of the experiment, no significant difference was found between four temperature conditions on phage density, ranging from 6.20-6.23 log10 PFU/mL (P>0.05). Under 10% SM medium, phage preservation at room temperature provided the optimum density at 6.31 log10 PFU/mL. In addition, phages preserved in a 5% DMSO medium were of similar density values across all temperature treatments. Still, their availability after 12 month-storage (88.0-88.5%) was significantly lower (P<0.05) than that of 50% glycerol and 10% SM. Moreover, for phage lysis capacity, low temperatures (4oC, -20oC, and -80oC) were superior to room temperature used for preservation. Considering the density, lysis capacity, and practical convenience, storing phages at 4°C in a 50% Glycerol medium is recommended

    Perceptions of the seriousness of major public health problems during the COVID-19 pandemic in seven middle-income countries

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    INTRODUCTION: Public perception of the seriousness of the COVID-19 pandemic compared to six other major public health problems (alcoholism and drug use, HIV/AIDS, malaria, tuberculosis, lung cancer and respiratory diseases caused by air pollution and smoking, and water-borne diseases like diarrhea) is unclear. We designed a survey to examine this issue using YouGov's internet panels in seven middle-income countries in Africa, Asia, and Latin America in early 2022. METHODS: Respondents rank ordered the seriousness of the seven health problems using a repeated best-worst question format. Rank-ordered logit models allow comparisons within and across countries and assessment of covariates. RESULTS: In six of the seven countries, respondents perceived other respiratory illnesses to be a more serious problem than COVID-19. Only in Vietnam was COVID-19 ranked above other respiratory illnesses. Alcoholism and drug use was ranked the second most serious problem in the African countries. HIV/AIDS ranked relatively high in all countries. Covariates, particularly a COVID-19 knowledge scale, explained differences within countries; statistics about the pandemic were highly correlated with differences in COVID-19's perceived seriousness. CONCLUSIONS: People in the seven middle-income countries perceived COVID-19 to be serious (on par with HIV/AIDS) but not as serious as other respiratory illnesses. In the African countries, respondents perceived alcoholism and drug use as more serious than COVID-19. Our survey-based approach can be used to quickly understand how the threat of a newly emergent disease, like COVID-19, fits into the larger context of public perceptions of the seriousness of health problems
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