Tooth loss and the risk of cognitive decline and dementia: A meta-analysis of cohort studies

IntroductionEpidemiological studies have shown that tooth loss may be associated with an increased risk of cognitive decline and dementia. However, some results do not show a significant association. Therefore, we performed a meta-analysis to evaluate this association.MethodsRelevant cohort studies were searched in PubMed, Embase, Web of Science (up to May 2022), and the reference lists of retrieved articles. The pooled relative risk (RR) and 95% confidence intervals were computed using a random-effects model (CI). Heterogeneity was evaluated using the I2 statistic. Publication bias was evaluated using the Begg's and Egger's tests.ResultsEighteen cohort studies met the inclusion criteria. Original studies with 356,297 participants with an average follow-up of 8.6 years (ranging from 2 to 20 years) were included in this study. The pooled RRs of tooth loss on dementia and cognitive decline were 1.15 (95% CI: 1.10–1.20; P < 0.01, I2 = 67.4%) and 1.20 (95% CI: 1.14–1.26; P = 0.04, I2 = 42.3%), respectively. The results of the subgroup analysis showed an increased association between tooth loss and Alzheimer's disease (AD) (RR = 1.12, 95% CI: 1.02–1.23) and vascular dementia (VaD) (RR = 1.25, 95% CI: 1.06–1.47). The results of the subgroup analysis also showed that pooled RRs varied by geographic location, sex, use of dentures, number of teeth or edentulous status, dental assessment, and follow-up duration. None of the Begg's and Egger's tests or funnel plots showed evidence of publication bias.DiscussionTooth loss is associated with a significantly increased risk of cognitive decline and dementia, suggesting that adequate natural teeth are important for cognitive function in older adults. The likely mechanisms mostly suggested include nutrition, inflammation, and neural feedback, especially deficiency of several nutrients like vitamin D

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Effect of higher heating rate during continuous annealing on microstructure and mechanical properties of cold-rolled 590 MPa dual-phase steel

In this presentation, the effect of higher heating rate in continuous annealing on microstructure and mechanical properties of a cold-rolled 590 MPa ferrite-martensite dual-phase steel were investigated by using microstructural observation and mechanical property measurement. The results show that compared with the conventional continuous annealed steels heated at a rate of 5 ∘C/s (CA), the average ferrite grain sizes heated at a higher rate (300 ∘C/s, HRA) was obviously refined from 15.6 μm to 5.3 μm. The morphology of martensite is observed to shift from network along ferrite grain boundaries to uniformly dispersed in the final DP590 microstructure. Twinned substructure of martensite can be found when heated at a higher heating rate in continuous annealing. EBSD orientation maps show that the fraction of low angle grain boundary is increased in HRA sample compared to CA sample. The HRA sample has excellent mechanical properties when compared to the CA sample. The variations of strength, elongation, strain hardening behavior and fracture mechanism of the this DP590 steel with different heating routine were further discussed in relation to microstructural features

Effect of higher heating rate during continuous annealing on microstructure and mechanical properties of cold-rolled 590 MPa dual-phase steel

In this presentation, the effect of higher heating rate in continuous annealing on microstructure and mechanical properties of a cold-rolled 590 MPa ferrite-martensite dual-phase steel were investigated by using microstructural observation and mechanical property measurement. The results show that compared with the conventional continuous annealed steels heated at a rate of 5 ∘C/s (CA), the average ferrite grain sizes heated at a higher rate (300 ∘C/s, HRA) was obviously refined from 15.6 μm to 5.3 μm. The morphology of martensite is observed to shift from network along ferrite grain boundaries to uniformly dispersed in the final DP590 microstructure. Twinned substructure of martensite can be found when heated at a higher heating rate in continuous annealing. EBSD orientation maps show that the fraction of low angle grain boundary is increased in HRA sample compared to CA sample. The HRA sample has excellent mechanical properties when compared to the CA sample. The variations of strength, elongation, strain hardening behavior and fracture mechanism of the this DP590 steel with different heating routine were further discussed in relation to microstructural features

Dependence of Grain Size on Mechanical Properties and Microstructures of High Manganese Austenitic Steel

AbstractA high manganese austenitic steel Fe-25Mn-3Cr-3Al-0.3C-0.01N (in wt. pct) with grain sizes 2.2∼28.7μm was obtained by annealing the cold rolled sheet at temperature ranging from 700°C to 1000°C. Dependence of grain size on the mechanical properties and microstructures of this high manganese steel were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and room temperature tensile test. The results show that, with the increase of grain size from 2.2μm to 28.7μm, the yield and ultimate tensile strengths of this steel were decreased from 410.0MPa to 232.5MPa and 725.0MPa to 517.0MPa, respectively. And the elongation of this steel was accordingly increased from 15.4% to 54.2%. Additionally, deformation twins are easy to form during tensile deformation when the initial grain size is increased

Genetic and Haplotype Diversity of Manila Clam <i>Ruditapes philippinarum</i> in Different Regions of China Based on Three Molecular Markers

China has the largest production yield of Manila clam Ruditapes philippinarum in the world. Most of the clam seeds for aquaculture are mainly derived from artificial breeding in southern China, likely resulting in the loss of genetic variation and inbreeding depression. To understand the genetic and haplotype diversity of R. philippinarum, 14 clam populations sampled from different regions of China were analyzed by three molecular markers, including COI, 16SrRNA and ITS. Based on the results of the COI and ITS genes, the 14 populations showed a moderate to high level of genetic diversity, with an average haplotype diversity of 0.9242 and nucleotide diversity of 0.05248. AMOVA showed that there was significant genetic differentiation among all populations (mean FST of the total population was 0.4534). Pairwise FST analysis showed that genetic differentiation reached significant levels between Laizhou and other populations. Two Laizhou populations showed great divergence from other populations, forming an independent branch in the phylogenetic tree. The shared haplotypes Hap_2 and Hap_4 of COI appeared most frequently in most clam populations. In contrast, 16SrRNA analysis of the clam populations revealed the dominated haplotype Hap_2, accounting for 70% of the total number of individuals. The haplotype diversity of the Laizhou population (Laizhou shell-wide (KK) and Laizhou dock (LZMT)) was relatively higher than other populations, showing multiple unique haplotypes (e.g., Hap_40, Hap_41 and Hap_42). These findings of genetic and haplotype diversity of clam populations provide guiding information for genetic resource conservation and genetic improvement of the commercially important R. philippinarum