18 research outputs found

    The effect of bacterial cellulose nanocrystals on the shear bond strength of resin modified glass ionomer cement to dentin

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    The present study aimed to investigate the effect of bacterial cellulose nanocrystals (BCNC) on the shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC) to dentin. A total of 48 freshly extracted intact third molars were randomly di

    Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

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    Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

    Global, regional, and national age-sex-specific mortality and life expectancy, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

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    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

    The Comparison of the Effects of Two Fatigue Protocols on Triceps- Surae Musculotendinous Stiffness in Healthy Female Students

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    Background: Previous studies have investigated different effects of muscle fatigue on body systems. However, there are no reports on the effect of fatigue protocol and its level on musculotendinous stiffness (MTS) of the tricep-surae. This study was designed to compare the effects of 2 levels of submaximal fatigue contraction on MTS of triceps-surae. Methods: Twenty female students by simple randomized sampling participated in this study. Triceps-surae musculotendinous stiffness was measured before and after two fatigue protocols. The fatigue protocols were comprised of a continuous isometric voluntary plantar flexion contraction (25% and 70% maximum voluntary contraction) until the contraction could no longer be maintained. The free oscillation technique was used to measure MTS of the triceps-surae. A Kistler force plate was used to measure the force applied. Results: Musculotendinous stiffness decreased immediately after both fatigue protocols (P≀0.05). Data analysis with RM ANOVA showed that there was no significant difference between the two protocols with respect to the decrease in MTS stiffness of the triceps-surae. Moreover, the decrease in stiffness did not change for 15 min after the two fatigue protocols (P>0.05). Conclusion: Musculotendinous stiffness of the triceps-surae decreased significantly after both fatigue protocols, and there was no significant difference between the two protocols with respect to change in triceps-surae musculotendinous stiffness. This result may be due to similar type of contraction in protocols, the learning effect, or the effect of central fatigue

    The comparative evaluation of the effects of quercetin, α‐tocopherol, and chlorhexidine dentin pretreatments on the durability of universal adhesives

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    Abstract Objective The aim of this study was to evaluate and compare the effects of chlorhexidine, quercetin, and α‐tocopherol on the shear bond strength of universal adhesives in the short (24h) and long term (6 months). Material and Methods Ninety‐six extracted sound molars were collected and divided randomly into four groups: control (no treatment), 2% chlorhexidine, 10% α‐tocopherol, and 1% quercetin. The solutions were prepared and applied to the teeth for 60 s, followed by application of All‐Bond universal adhesive and composite build‐up. Half of the specimens in each group (n = 12) were tested for shear bond strength (SBS) after 24 h of storage and the other half were kept in distilled water for 6 months and then tested for shear bond strength. The shear bond strength test was performed and the failure modes were determined using a stereomicroscope. The data were analyzed using two‐way analysis of variance and Tukey's post hoc tests with p ˂ .05 as the significance level. Results The results of the two‐way analysis of variance test showed that there was no significant difference in immediate SBS, and after 6 months, α‐tocopherol had the lowest SBS in comparison to the control and CHX subgroups (p < .05). The t‐test showed that the shear bond strength in the α‐tocopherol and quercetin groups was significantly decreased after 6 months. Conclusion It can be concluded that the solutions used in this study had no adverse effect on immediate SBS. After 6 months, the CHX could preserve SBS in comparison to other groups

    Preparation and Bioavailability Analysis of Ferrous Bis Alanine Chelate as a New Micronutrient for Treatment of Iron Deficiency Anemia

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    Purpose: One of the most nutritional disorders around the world is iron deficiency. A novel iron compound was synthesized by chelating ferrous ions with alanine for prevention and treatment of iron deficiency anemia. Methods: The newly synthesized compound was characterized both qualitatively and quantitatively by Fourier Transform Infrared (FT-IR) spectroscopy. The bioavailability of newly synthesized iron micronutrient was evaluated in four groups of Wistar rats. The group I was a negative control group and the other three groups received three different iron formulations. After 14 days, the blood samples were taken and analyzed accordingly. Results: Calculations showed that more than 91.8% of iron was incorporated in the chelate formulation. In vivo studies showed that serum iron, total iron binding capacity and hemoglobin concentrations were significantly increased in group IV, which received ferrous bis alanine chelate compared with the negative control group (p<0.05) and also group II, which received ferrous sulfate.7H2O (p<0.05). It indicates that the new formulation considerably improves the blood iron status compared with the conventional iron compounds. There were no significant differences (p<0.05) in the serum iron between group IV and group III, which received ferrous bis glycine. Conclusion: The results showed better bioavailability of ferrous bis alanine as a new micronutrient for treatment of iron deficiency anemia in comparison with ferrous sulfate. Ferrous bis alanine could be considered as a suitable supplement for prevention and treatment of iron deficiency anemia

    Comparative evaluation of the postbleaching application of sodium ascorbate, alpha‐tocopherol, and quercetin on shear bond strength of composite resin to enamel

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    Abstract Objective This study aimed to evaluate and compare the impacts of the postbleaching application of sodium ascorbate, alpha‐tocopherol, and quercetin on the shear bond strength (SBS) of composite resin. Material and Methods 60 extracted intact maxillary first premolars were collected and were randomly divided into five experimental groups as follows (n=12): Group A (negative control): no bleaching, Group B (positive control): bleaching with 40% hydrogen peroxide (HP), Group C: HP±10% sodium ascorbate for 10min, Group D: HP±10% alpha‐tocopherol for 10min, and Group E: HP±1% quercetin for 10min. Composite bonding was done immediately after bleaching for Groups B‐E and without any treatment for Group A. After being stored in distilled water at room temperature for 24h, all specimens were tested for SBS in the universal testing machine. One‐way analysis of variance and Tukey's post‐hoc test were used to analyze the SBS values of all groups. Results The results showed that the bonding of composite to the unbleached group exhibited the highest mean value of SBS (22.68±2.91MPa). Among the antioxidant‐treated groups, the highest SBS value was detected in quercetin‐treated specimens (15.45±1.58MPa), which was significantly different from the positive control group (p<.05). Conclusion It could be concluded that 10% quercetin applied for 10min increased the bond strength to bleached enamel, but it was not able to reverse it completely

    Development of a microfluidic method to study enhanced oil recovery by low salinity water flooding

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    Microfluidics is an appealing method to study processes at rock pore scale such as oil recovery due to the similar size range. It also offers several advantages over the conventional core flooding methodology, for example, easy cleaning and re-use of the same porous network chips or the option to visually track the process. In this study, the effect of injection rate, flood volume, micromodel structure, initial brine saturation, aging, oil type, brine concentration, and composition are systematically investigated. The recovery process is evaluated based on a series of images taken during the experiment. The remaining crude oil saturation reaches a steady state after injection of a few pore-volumes of the brine flood. The higher the injection rate, the higher the emulsification and agitation, leading to unstable displacement. Low salinity brine recovered more of the oil than the high salinity brine. Aging, initial brine saturation, and presence of divalent ions in the flood showed to decrease the oil recovery. Most of the tests in this study showed viscous fingering. The analysis of the experimental parameters allowed to develop a reliable and repeatable procedure for microfluidic water flooding. With the method in place, the enhanced oil recovery test developed based on different variables showed an increase of up to 2% of the original oil in place at the tertiary stage

    Lignosulfonates in Crude Oil Processing: Interactions with Asphaltenes at the Oil/Water Interface and Screening of Potential Applications

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    The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, the interfacial tension between brine and xylene and interfacial dilational rheology properties of LS samples were measured. It was found that the most surface-active LS sample has the lowest molecular weight in agreement with the results from the literature. In the presence of asphaltenes, all three LS samples were able to compete with asphaltenes, the most polar crude oil component, at the interface and form mixed LS−asphaltene interfaces. However, only the most surface-active LS sample among the three tested could fully desorb asphaltenes at the highest tested LS concentration (500 ppm). Second, three possible applications were screened. LSs were tested to prevent the formation of w/o crude oil emulsions or to break these. However, the opposite effect was observed, that is, stabilization of water-in-crude oil emulsions. The potential application of LS in produced water (PW) clarification was furthermore considered. The kinetics of PW clarification was found unaffected by the presence of LS, even at very high concentrations (1000 ppm). Finally, the potential of LS for enhanced oil recovery was assessed. The LS flood changed the surface wettability toward water wetness for one of the samples, yet LS injection did not recover additional oil beyond brine recovery. It was concluded that LS has interesting properties, such as the potential to compete with crude oil indigenous components at the oil/water interface. The stabilization action of LS was dominant over any destabilization effect, which led to the conclusion that LSs are more efficient for stabilizing emulsions rather than destabilizing
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