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Aims Episodic memory depends on the maintenance of an intact default mode network (DMN), and is one of the earliest cognitive domains to become impaired in type 2 diabetes mellitus (T2DM). Therefore, exploring the alterations in task-related DMN deactivation and functional connectivity that affect episodic memory in T2DM will help to enhance our understanding of the allocation patterns underlying memory function in T2DM. Methods The current study assessed changes in DMN activation and architecture during the encoding of a functional magnetic resonance imaging task in 39 patients with T2DM and 41 healthy controls which were recruited from local communities in Beijing, China. Results We found that patients with T2DM and intact episodic memory performance exhibited reduced deactivation in the right precuneus and the middle temporal gyrus during the episodic memory task. Furthermore, an anterior-posterior disconnection phenotype and altered topological configuration of the DMN were observed in patients with T2DM using graph-theoretical approaches. Correlation analysis showed that altered deactivation during the episodic memory task was closely related to connectivity dysfunction and topological properties in the DMN. Conclusions Our findings demonstrate that the maintenance of memory in patients with T2DM involves reduced deactivation and impaired anterior-posterior connections in the DMN during encoding. [ABSTRACT FROM AUTHOR]

Adults without diabetes are not completely healthy; they are probably heterogeneous with several potential health problems. The management of hemoglobin A1c (HbA1c) is crucial among patients with diabetes; but whether similar management strategy is needed for adults without diabetes is unclear. Thus, this study aimed to investigate the associations of visit-to-visit HbA1c variability with incident dementia and hippocampal volume among middle-aged and older adults without diabetes, providing potential insights into this question. We conducted a prospective analysis for incident dementia in 10,792 participants (mean age 58.9 years, 47.8 % men) from the UK Biobank. A subgroup of 3793 participants (mean age 57.8 years, 48.6 % men) was included in the analysis for hippocampal volume. We defined HbA1c variability as the difference in HbA1c divided by the mean HbA1c over the 2 sequential visits ([latter − former]/mean). Dementia was identified using hospital inpatient records with ICD-9 codes. T1-structural brain magnetic resonance imaging was conducted to derive hippocampal volume (normalized for head size). The nonlinear and linear associations were examined using restricted cubic spline (RCS) models, Cox regression models, and multiple linear regression models. During a mean follow-up (since the second round) of 8.4 years, 90 (0.8 %) participants developed dementia. The RCS models suggested no significant nonlinear associations of HbA1c variability with incident dementia and hippocampal volume, respectively (All P > 0.05). Above an optimal cutoff of HbA1c variability at 0.08, high HbA1c variability (increment in HbA1c) was associated with an increased risk of dementia (Hazard Ratio, 1.88; 95 % Confidence Interval, 1.13 to 3.14, P = 0.015), and lower hippocampal volume (coefficient, −96.84 mm3, P = 0.037), respectively, in models with adjustment of covariates including age, sex, etc. Similar results were found for a different cut-off of 0. A series of sensitivity analyses verified the robustness of the findings. Among middle-aged and older adults without diabetes, increasing visit-to-visit HbA1c variability was associated with an increased dementia risk and lower hippocampal volume. The findings highlight the importance of monitoring and controlling HbA1c fluctuation in apparently healthy adults without diabetes. • High visit-to-visit HbA1c variability was associated with an increased dementia risk. • High visit-to-visit HbA1c variability was associated with low hippocampal volume. • Monitoring HbA1c fluctuation is of great importance in adults without diabetes. [ABSTRACT FROM AUTHOR]

• A new hybrid strengthening method with core-filling and external unbonded prestressing steel strands was proposed. • A quadratic relationship was shown between damage and enhancement coefficients. • Analytical and finite element models were developed for evaluating the flexural behaviours of hollow core beams strengthened with hybrid strengthening method. Extensive investigations show that the core-filling method can markedly improve the shear behaviour of hollow core beams (HCBs). However, few investigations were carried out to study the flexural behaviours of the HCBs strengthened with this method. In this study, the flexural behaviours were first studied, where the HCBs were strengthened with a hybrid strengthening method of the core-filling and external unbonded prestressing steel strands. Six types of HCB specimens were fabricated and investigated. The initial damage and prestress levels were selected as the main parameters. Before strengthening, the HCB specimens were loaded to 40.6 %, 66.3 % and 100 % of their ultimate load to pre-set some cracks in the concrete beams, which corresponded to the maximum crack widths of 0.2 mm, 0.4 mm and wider than 1.5 mm, respectively. Compared with the control beam, the strengthening with the core-filling improved the flexural load carrying capacity by 3.93 %, whereas the hybrid strengthening method improved by 33.67 %; the cracking loads for the two strengthening methods increased by 10.34 % and 128.28 %, respectively. Moreover, the experimental results showed that the initial flexural stiffness can be markedly improved with the hybrid strengthening method. However, the initial damage level had little influence on the final crack width. In addition, an analytical model was proposed to evaluate the flexural behaviors of the strengthened HCBs. The simulation results of the preload, ultimate load and failure modes agreed well with the experimental ones. [ABSTRACT FROM AUTHOR]

To address the condition that community-based geriatric services for the assessment and promotion of older adults' cognitive ability systemically aimed at delaying or preventing dementia is lacking in China. A community-based model including cognitive assessment and training, geriatric health guidance and long-term support was designed based on a prospective cohort study. Participants (N = 5593) were all from an ongoing cohort study, the Beijing Aging Brain Rejuvenation Initiative (BABRI) study. We conducted receiver operating characteristic, stepwise logistic regression and branch-and-bound algorithm analyses to select the most effective tests from the BABRI neuropsychological test battery. Canonical discriminant analysis was conducted to extract the first canonical variable as a composite index of the tests. In addition, we developed comprehensive surveys and computerized cognitive trainings targeting every cognitive domain. The BABRI brain health system (BABRI-BHS) was designed to include SCREEN, ASSESS, and DIAGNOSE sessions. When distinguishing cognitively impaired older adults from cognitively healthy older adults, the canonical variable extracted from tests in the SCREEN session achieved an area under the curve (AUC) of 0.730 [95% confidence interval (95% CI) 0.671–0.789], with a sensitivity of 0.630 and a specificity of 0.780; in the ASSESS session, the AUC was 0.906 (95% CI 0.894–0.917), the sensitivity was 0.809, and the specificity was 0.854. A stepwise screening pathway is recommended when using the BABRI-BHS in communities to divide older adults into subtypes and to provide targeted interventions and long-term geriatric health guidance. The BABRI-BHS is an effective and efficient geriatric health care solution that is suitable for community-based dementia risk screening, providing stepwise cognitive assessments and helping older adults acquire tailored interventions and guidance conveniently. [ABSTRACT FROM AUTHOR]