137 research outputs found

    Alloy Steel: Properties and Use First-Principles Quantum Mechanical Approach to Stainless Steel Alloys

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    Accurate description of materials requires the most advanced atomic-scale techniques from both experimental and theoretical areas. In spite of the vast number of available techniques, however, the experimental study of the atomic-scale properties and phenomena even in simple solids is rather difficult. In steels the challenges become more complex due to the interplay between the structural, chemical and magnetic effects. On the other hand, advanced computational methods based on density functional theory ensure a proper platform for studying the fundamental properties of steel materials from first-principles. In 1980’s the first-principles description of the thermodynamic properties of elemental iron was still on the borderline of atomistic simulations. Today the numerous application- oriented activities at the industrial and academic sectors are paired by a rapidly increasing scientific interest. This is reflected by the number of publications on ab initio steel research, which has increased from null to about one thousand within the last two decades. Our research group has a well established position in developing and applying computational codes for steel related applications. Using our ab initio tools, we have presented an insight to the electronic and magnetic structure, and micromechanical properties of austenite and ferrite stainless steel alloys. In the present contribution, we review the most important developments within the ab initio quantum mechanics aided steel design with special emphasis on the role of magnetism on the fundamental properties of alloy steels

    Assessment of Maximum Bite Force in Oral Submucous Fibrosis Patients: A Preliminary Study

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    Objective: To determine the maximum bite force (MBF) in oral submucous fibrosis (OSMF) patients and to compare them with that of healthy subjects. Material and Methods: Twenty patients who were clinically confirmed, as OSMF and 20 healthy controls matched for age, gender, and number of intact functional teeth were included in this study. For each subject, age, gender, weight, height and body mass index (BMI) were recorded. The MBF registration was carried out by the two evaluators, who were previously calibrated. Bite force was measured in the first molar region using a force transducer occlusal force meter for each subject seated at the upright position, with Frankfort's plane nearly parallel to the floor, and no head support. The Student’s independent t-test was used to determine the statistical significance in relation to mean height, weight, BMI and the presence of number of intact teeth and MBF between the healthy subjects and OSMF individuals. A comparison of grades of OSMF with all variables was carried out by one-way ANOVA test. Results: No significant difference was found in mean age, mean height, weight, BMI and the presence of the number of intact teeth between healthy individuals and OSMF patients. The mean MBF in healthy subjects was 628.23 ± 24.39 N and 635.47 ± 31.22 N in OSMF patients. Even though the healthy subjects reported a higher MBF than OSMF patients did, the difference was statistically non-significant. With regards to sides, no significant difference was observed in mean MBF in healthy subjects and OSMF patients on the right (p=0.7818) and left side (p=0.6154). Conclusion: The healthy subjects reported higher MBF values than OSMF patients did and the difference was statistically non-significant

    Stainless Steel Alloys from First-principles Theory

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    Gaining an accurate description of materials obviously requires the most advanced atomic-scale techniques fromboth experimental and theoretical areas. In spite of the vast number of available techniques, however, theexperimental study of the atomic-scale properties and phenomena even in simple solids is rather difficult. Insteels the challenges become more complex due to the interplay between the structural, chemical and magneticeffects. On the other hand, advanced computational methods based on density functional theory ensure a properplatform for studying the fundamental properties of steel materials from first-principles. Our group at the RoyalInstitute of Technology in Stockholm has an international position in developing and applying computationalcodes for such applications. Using our ab initio tools, we have presented an insight to the electronic andmagnetic structure, and micromechanical properties of austenitic stainless steel alloys. In the presentcontribution, we review the most important developments within the ab initio quantum-mechanics-aided steeldesign with special emphasis on the role of magnetism on the fundamental properties of alloy steels

    Quantitative analysis of powder mixtures by raman spectrometry : the influence of particle size and its correction

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    Particle size distribution and compactness have significant confounding effects on Raman signals of powder mixtures, which cannot be effectively modeled or corrected by traditional multivariate linear calibration methods such as partial least-squares (PLS), and therefore greatly deteriorate the predictive abilities of Raman calibration models for powder mixtures. The ability to obtain directly quantitative information from Raman signals of powder mixtures with varying particle size distribution and compactness is, therefore, of considerable interest In this study, an advanced quantitative Raman calibration model was developed to explicitly account for the confounding effects of particle size distribution and compactness on Raman signals of powder mixtures. Under the theoretical guidance of the proposed Raman calibration model, an advanced dual calibration strategy was adopted to separate the Raman contributions caused by the changes in mass fractions of the constituents in powder mixtures from those induced by the variations in the physical properties of samples, and hence achieve accurate quantitative determination for powder mixture samples. The proposed Raman calibration model was applied to the quantitative analysis of backscatter Raman measurements of a proof-of-concept model system of powder mixtures consisting of barium nitrate and potassium chromate. The average relative prediction error of prediction obtained by the proposed Raman calibration model was less than one-third of the corresponding value of the best performing PLS model for mass fractions of barium nitrate in powder mixtures with variations in particle size distribution, as well as compactness

    Albumin Nano-Encapsulation of Piceatannol Enhances Its Anticancer Potential in Colon Cancer Via Downregulation of Nuclear p65 and HIF-1 alpha

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    Piceatannol (PIC) is known to have anticancer activity, which has been attributed to its ability to block the proliferation of cancer cells via suppression of the NF-kB signaling pathway. However, its effect on hypoxia-inducible factor (HIF) is not well known in cancer. In this study, PIC was loaded into bovine serum albumin (BSA) by desolvation method as PIC-BSA nanoparticles (NPs). These PIC-BSA nanoparticles were assessed for in vitro cytotoxicity, migration, invasion, and colony formation studies and levels of p65 and HIF-1α. Our results indicate that PIC-BSA NPs were more effective in downregulating the expression of nuclear p65 and HIF-1α in colon cancer cells as compared to free PIC. We also observed a significant reduction in inflammation induced by chemical colitis in mice by PIC-BSA NPs. Furthermore, a significant reduction in tumor size and number of colon tumors was also observed in the murine model of colitis-associated colorectal cancer, when treated with PIC-BSA NPs as compared to free PIC. The overall results indicate that PIC, when formulated as PIC-BSA NPs, enhances its therpautice potential. Our work could prompt further research in using natural anticancer agents as nanoparticels with possiable human clinical trails. This could lead to the development of a new line of safe and effective therapeutics for cancer patients

    Adapting a clinical practice guideline for management of patients with knee and hip osteoarthritis by Hong Kong physiotherapists

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    Abstract Knee and hip osteoarthritis are common disabling conditions globally. Although numerous international clinical practice guidelines exist to guide physiotherapy management, not all recommendations issued from these guidelines can be translated to other contexts without considering the cultural acceptability and clinical implementability of targeted countries. Because the ADAPTE framework provides a robust methodology to adapt guidelines to the local context, this study used its methodology to adapt high-quality guideline recommendations to promote optimal physiotherapy care for knee and hip osteoarthritis in Hong Kong. The ADAPTE framework was used and modified to complete the adaptation process. International clinical practice guidelines were identified from eight guideline clearinghouses and six electronic databases. Two independent reviewers critically appraised the eligible guidelines using the AGREE II tool. We extracted and tabulated recommendations from high-quality guidelines. A voting-based consensus among interdisciplinary experts was conducted to decide on suitable recommendations for the Hong Kong context and whether there was a need to modify them. Pertinent recommendations were then translated into the traditional Chinese language. Our team members suggested modifying four tools and adding one to explore the patient’s feedback on the recommendations, to the ADAPTE framework. The adaptation was performed on three high-quality guidelines. We adapted 28 and 20 recommendations for treating knee and hip osteoarthritis, respectively. We recommend a multimodal treatment for managing knee and hip osteoarthritis. Land- and aquatic-based exercises, patient education, and self-management were strongly recommended for patients with knee osteoarthritis. Land- and aquatic-based exercises were strongly recommended for patients with hip osteoarthritis. This is the first adaptation study in Hong Kong. It provides guidance to local physiotherapists on managing patients with knee and hip osteoarthritis. Future studies should test the effectiveness of implementing this adapted guideline to improve local physiotherapy care in Hong Kong
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