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High-cycle fatigue tests of Pt–Al bond coated and bare single crystal superalloys were conducted at 700 °C and 800 °C, aiming at investigating the effect of bond coat on the high-cycle fatigue properties of a single crystal superalloy. The impact of bond coat was studied merely on the tensile and creep properties of this superalloy, but was not found on the high-cycle fatigue behavior of this alloy. The experimental results showed that the bond coat was found to be beneficial at 800 °C or under low stresses at 700 °C owing to the fact that cracks were retarded by the fine grains in the IDZ, the P-type rafted γ′ phases in the substrate or the coat/substrate interface, respectively. However, the bond coat was detrimental under high stresses at 700 °C owing to the rapid propagation of the early cracking and the brittle nature of bond coat. Moreover, EBSD results showed the all bond coat cracks mainly initiated at the surface of the coated specimens and started from grains with {123} slip system within bond coat. Fatigue tested samples at 800 °C showed a comparatively higher Schmid factor value than that at 700 °C. Following the fatigue test, TEM tests indicated that in the superalloy close to the bond coat, the dislocation networks formed due to the activity of various slip systems at 700 °C; under 450 MPa at 800 °C in this region, a special a0 superdislocation with two segments of compact core was observed in the rafted γ′ phases.

Topic Visual impairment (VI) and cognitive impairment (CIM) are prevalent age-related conditions that impose substantial burden on the society. Findings on the hypothesized bidirectional association of VI and CIM remains equivocal. Hence, we conducted a systematic review and meta-analysis to examine this bidirectional relationship. Clinical Relevance Sixty percent risk of CIM has not been well elucidated in the literature. A bidirectional relationship between VI and CIM may support the development of strategies for early detection and management of risk factors for both conditions in older people. Methods PubMed, Embase, and Cochrane Central registers were searched systematically for observational studies, published from inception until April 6, 2020, in adults 40 years of age or older reporting objectively measured VI and CIM assessment using clinically validated cognitive screening tests or diagnostic evaluation. Meta-analyses on cross-sectional and longitudinal associations between VI and CIM outcomes (any CIM assessed using screening tests and clinically diagnosed dementia) were examined. Random effect models were used to generate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We also examined study quality, publication bias, and heterogeneity. Results Forty studies were included (n = 47 913 570). Meta-analyses confirmed that persons with VI were more likely to have CIM, with significantly higher odds of: (1) any CIM (cross-sectional: OR, 2.38 [95% CI, 1.84–3.07]; longitudinal: OR, 1.66 [95% CI, 1.46–1.89]) and (2) clinically diagnosed dementia (cross-sectional: OR, 2.43 [95% CI, 1.48–4.01]; longitudinal: OR, 2.09 [95% CI, 1.37–3.21]) compared with persons without VI. Significant heterogeneity was explained partially by differences in age, sex, and follow-up duration. Also, some evidence suggested that individuals with CIM, relative to cognitively intact persons, were more likely to have VI, with most articles (8/9 [89%]) reporting significantly positive associations; however, meta-analyses on this association could not be conducted because of insufficient data. Discussion Overall, our work suggests that VI is a risk factor of CIM, although further work is needed to confirm the association of CIM as a risk factor for VI. Strategies for early detection and management of both conditions in older people may minimize individual clinical and public health consequences.

SnS2 is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS2_en have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS2 after intercalation revealed defects and stacking mismatches among the SnS2 layers caused by the intercalation. UV–Vis absorption studies showed a red shift in the band edge of the SnS2 material after intercalation. The band edge was 2.2 eV for pristine SnS2; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively.