87 research outputs found
Effect of 2% Chlorhexidine on Shear Bond Strength of Composite Resins to Dentin
Abstract
Background and Aim: Intracanal medicaments can affect the bond strength of
composite to dentin. The aim of this study was to evaluate the effect of 2% chlorhexidine
(CHX) gel as an intracanal medicament on shear bond strength of three different
composite resins to dentin.
Materials and Methods: In this in-vitro study, 60 intact extracted human premolars
were utilized. Each tooth was sectioned vertically and dentin of the buccal surface was
exposed. Then, specimens were divided into six groups of 10 teeth. In groups 1-3, dentin
was exposed to CHX and in groups 4-6, dentin was exposed to saline. All prepared
surfaces were rinsed with distilled water and dentin bonding agent specific for each
composite was applied on the dentin surfaces. Z100, Z350 and P90 composites were
applied to the treated surfaces and cured. The shear bond strength was recorded in
Newtons and converted to MPa. Data were analyzed using the Kruskal-Wallis and Dunn
tests.
Results: The lowest mean shear bond strength was reported for normal saline and Z100
composite group (18.47 MPa) and the highest for CHX and Z350 group (42.26 MPa). No
statistically significant difference in bond strength values was found between normal
saline and CHX groups (P>0.05). There was a significant difference in bond strength
values of different composite resins in normal saline (P<0.05) and also in CHX groups
(P<0.05).
Conclusion: Application of 2% chlorhexidine gel slightly but not significantly increases
the mean shear bond strength of composite to dentin. The type of composite influences
the shear bond strength to denti
Recognition and identification analysis of the features of the epistemology of the MOOC (Massive and Courses)
Background and Objectives: One of the forms of knowledge acquisition in the current era is the distance education system, which has changed the traditional teaching methods, made it possible for everyone to learn everywhere and at any time, and has established social justice in the distribution of resources and facilities. It has created the necessary conditions for standardized education and in accordance with the needs of individuals and society, as well as the significant help that this system can easily and timely modernize education, save time, money and energy consumption, create opportunities for continuing education for employed people, strengthen specializations and creates calmness and reduces anxiety. And given that in addition to classroom teaching at the university, distance learning is now a valid method worldwide and UNESCO and other educational organizations around the world emphasize the expansion of distance learning, it is necessary to seriously develop it and the foundations of epistemology; and make it known to policymakers, planners and learners.The present study was conducted with the aim of identification and assessing the epistemological characteristics of MOOC (massive and courses). Methods: For this purpose, two methods of exploratory search (qualitative) and a questionnaire (quantitative) method were used. In the qualitative part of the research environment, the relevant electronic sources related to the subject matter of the research including 20 related articles were selected. In the quantitative section from the statistical population of 60 specialists in planning distance education in 2018 in the country a sample of 36 people was selected through voluntary sampling. To analyze the qualitative data, content analysis method and content validity index were used for analyzing quantitative data from mean weight and Friedman test. Findings: The results of content analysis indicated that four episodes of the learner, the content, teaching organization and educational environment can be investigated in MOOC epistemology (massive and courses). A total of 35 criteria were identified and confirmed. Quantitative results show that improving the level of information and digital literacy of professors, and knowledge with previous cognitive structures are the most important criterions of the epistemological characteristics of the courses of MOOC; and the criteria of ease of usedigital content, the recruitment of information technology professionals, for knowledge courses and the provision of Internet-based learning group environment, are the most important criterion for epistemology of massive MOOC. Conclusion: The results showed that in the epistemology of massive courses the dim ===================================================================================== COPYRIGHTS ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers. ====================================================================================
Epinecidin-1, a highly potent marine antimicrobial peptide with anticancer and immunomodulatory activities
Background: Antibiotic-resistant pathogens are an emerging threat in this century. Epinecidin-1 is a multi-functional Antimicrobial Peptide (AMP) produced by Orange-spotted grouper (Epinephelus coioides) has been shown to have extensive potentials as an alternative for current antibiotics. Due to the huge costs for the study and the production of a new drug, if an antimicrobial peptide has other beneficial functions in addition to antimicrobial activities, it would be preferred. Methods: In this study, properties and applications of Epinecidin-1 were investigated and addressed comprehensively. To achieve this, the Google Scholar search engine and three databases of PubMed, Scopus, and Web of Science were used. Results: Epinecidin-1 is a cationic AMP with an alpha-helical structure. Seven functional usages of this peptide have been reported in the literature including antibacterial, antifungal, antiviral, antiprotozoal, anticancer, immunomodulatory, and wound healing properties. Moreover, this peptide has high potential to be used as an active ingredient in cleaning solutions as well as application in vaccine production. Conclusion: Due to significant antimicrobial activities tested on bacteria such as Staphylococcus aureus and Helicobacter pylori and also wound healing properties, Epi-1 has high potential to be considered as an important candidate for the production of new drugs and treatment of various infections including diabetic foot ulcer and peptic ulcer. Moreover, adjuvant-like properties of Epi-1 make it a suitable candidate for the studies related to an adjuvant. Other attractive properties such as anticancer effects have also been reported for this peptide which encourages further studies on this peptide. © 2019 The Author(s)
Non-alcoholic steatohepatitis and influence of age and gender on histopathologic findings
AIM: To characterize the histopathologic specifications of non-alcoholic steatohepatitis (NASH) according to age and gender. METHODS: An analytical cross-sectional study was conducted in two private gastroenterology clinics on biopsy proven patients suffering from NASH. Biopsy histopathologic findings as well as demographic and laboratory data of the patients at the time of biopsy were gathered retrospectively from clinical records. The grading and staging of histopathologic findings were performed according to the Brunt method after reevaluation of the slides by a pathologist. Patients were divided into two groups according to age (below and above 55 years). Mean quantitative grade of all pathologic findings were also calculated according to Brunt scoring values. RESULTS: A total number of 77 NASH patients, consisting of 58 males (75.3) and 19 (24.7) females with a mean age of 41.99 ± 11.80 years (range, 18-70 years), were enrolled. The mean age (48.72 ± 13.99 years vs 39.74 ± 10.16 years, P = 0.004) and aspartate aminotransferase level (75.11 ± 29.68 U/L vs 52.78 ± 25.00 U/L, P = 0.002) was significantly higher in female patients. Mean quantitative grade of hepatosteatosis was significantly higher in females (2.00 ± 0.82 vs 1.59 ± 0.68, P = 0.031) compared to males. Fifty four percent (34/65) of young patients had mild hepatosteatosis (Grade I) while only one patient (11.2) in the older group had grade I hepatosteatosis. Patients aged � 55 had significantly more severe hepatosteatosis (Grade III) (44.4 vs 9.5, P = 0.007) and the mean quantitative grade of hepatosteatosis was significantly higher among them (2.33 ± 0.71 vs 1.56 ± 0.67, P = 0.002). Multivariate analysis after omitting the confounding role of age revealed a higher grade of hepatosteatosis in female patients (P = 0.010). CONCLUSION: These findings point toward the possible influence of age in the severity of steatohepatitis, portal and lobar inflammation in patients suffering from NASH while gender independently might contribute to the level of steatohepatitis. © 2010 Baishideng
EFSA's OpenFoodTox: An open source toxicological database on chemicals in food and feed and its future developments
Since its creation in 2002, the European Food Safety Authority (EFSA) has produced risk assessments for over 5000 substances in >2000 Scientific Opinions, Statements and Conclusions through the work of its Scientific Panels, Units and Scientific Committee. OpenFoodTox is an open source toxicological database, available both for download and data visualisation which provides data for all substances evaluated by EFSA including substance characterisation, links to EFSA's outputs, applicable legislations regulations, and a summary of hazard identification and hazard characterisation data for human health, animal health and ecological assessments. The database has been structured using OECD harmonised templates for reporting chemical test summaries (OHTs) to facilitate data sharing with stakeholders with an interest in chemical risk assessment, such as sister agencies, international scientific advisory bodies, and others. This manuscript provides a description of OpenFoodTox including data model, content and tools to download and search the database. Examples of applications of OpenFoodTox in chemical risk assessment are discussed including new quantitative structure–activity relationship (QSAR) models, integration into tools (OECD QSAR Toolbox and AMBIT-2.0), assessment of environmental footprints and testing of threshold of toxicological concern (TTC) values for food related compounds. Finally, future developments for OpenFoodTox 2.0 include the integration of new properties, such as physico-chemical properties, exposure data, toxicokinetic information; and the future integration within in silico modelling platforms such as QSAR models and physiologically-based kinetic models. Such structured in vivo, in vitro and in silico hazard data provide different lines of evidence which can be assembled, weighed and integrated using harmonised Weight of Evidence approaches to support the use of New Approach Methodologies (NAMs) in chemical risk assessment and the reduction of animal testing
Epidermal neural crest stem cell transplantation as a promising therapeutic strategy for ischemic stroke
Introduction: Cell-based therapy is considered as promising strategy to cure stroke. However, employing appropriate type of stem cell to fulfill many therapeutic needs of cerebral ischemia is still challenging. In this regard, the current study was designed to elucidate therapeutic potential of epidermal neural crest stem cells (EPI-NCSCs) compared to bone marrow mesenchymal stem cells (BM-MSCs) in rat model of ischemic stroke. Methods: Ischemic stroke was induced by middle cerebral artery occlusion (MCAO) for 45 minutes. Immediately after reperfusion, EPI-NCSCs or BM-MSCs were transplanted via intra-arterial or intravenous route. A test for neurological function was performed before ischemia and 1, 3, and 7 days after MCAO. Also, infarct volume ratio and relative expression of 15 selected target genes were evaluated 7 days after transplantation. Results: EPI-NCSCs transplantation (both intra-arterial and intravenous) and BM-MSCs transplantation (only intra-arterial) tended to result in a better functional outcome, compared to the MCAO group; however, this difference was not statistically significant. The infarct volume ratio significantly decreased in NCSC-intra-arterial, NCSC-intravenous and MSC-intra-arterial groups compared to the control. EPI-NCSCs interventions led to higher expression levels of Bdnf, nestin, Sox10, doublecortin, β-III tubulin, Gfap, and interleukin-6, whereas neurotrophin-3 and interleukin-10 were decreased. On the other hand, BM-MSCs therapy resulted in upregulation of Gdnf, β-III tubulin, and Gfap and down-regulation of neurotrophin-3, interleukin-1, and interleukin-10. Conclusion: These findings highlight the therapeutic effects of EPI-NCSCs transplantation, probably through simultaneous induction of neuronal and glial formation, as well as Bdnf over-expression in a rat model of ischemic strok
New insights into the genetic etiology of Alzheimer's disease and related dementias.
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019
BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden
Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
BACKGROUND:
Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally.
METHODS:
The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950.
FINDINGS:
Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development.
INTERPRETATION:
This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing
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