Lifestyle factors and subjective well­being among older adults in China: A national community-based cohort study.

There has been limited research on the relationship between health habits and subjective well-being (SWB) among Chinese oldest older adults. This study aims to explore lifestyle factors associated with SWB in this population. We analyzed data from three waves (2008-2014) of the CLHLS, including 28,683 older adults. Lifestyle factors analyzed included fruit and vegetable intake, smoking, alcohol consumption, physical exercise, and social participation. Results suggested that high frequency of fruit and vegetable intake, current and past physical exercise, and high levels of social participation were associated with increased SWB. SWB was lower in older adults who never smoked compared to persistent smokers and in those who never drank alcohol or ceased drinking compared to persistent drinkers. We encourage older adults to enhance SWB through increased fruit and vegetable intake, physical exercise, and social participation. However, quitting smoking and drinking may not necessarily improve SWB, particularly in the context of China.

Tuning the Crystallization Mechanism by Composition Vacancy in Phase Change Materials.

Interface-influenced crystallization is crucial to understanding the nucleation- and growth-dominated crystallization mechanisms in phase-change materials (PCMs), but little is known. Here, we find that composition vacancy can reduce the interface energy by decreasing the coordinate number (CN) at the interface. Compared to growth-dominated GeTe, nucleation-dominated Ge2Sb2Te5 (GST) exhibits composition vacancies in the (111) interface to saturate or stabilize the Te-terminated plane. Together, the experimental and computational results provide evidence that GST prefers (111) with reduced CN. Furthermore, the (8 - n) bonding rule, rather than CN6, in the nuclei of both GeTe and GST results in lower interface energy, allowing crystallization to be observed at the simulation time in general PCMs. In comparison to GeTe, the reduced CN in the GST nuclei further decreases the interface energy, promoting faster nucleation. Our findings provide an approach to designing ultrafast phase-change memory through vacancy-stabilized interfaces.

Does unequal economic development contribute to the inequitable distribution of healthcare resources? Evidence from China spanning 2001-2020.

BACKGROUND: There is a dearth of research combining geographical big data on medical resource allocation and growth with various statistical data. Given the recent achievements of China in economic development and healthcare, this study takes China as an example to investigate the dynamic geographical distribution patterns of medical resources, utilizing data on healthcare resources from 290 cities in China, as well as economic and population-related data. The study aims to examine the correlation between economic growth and spatial distribution of medical resources, with the ultimate goal of providing evidence for promoting global health equity. METHODS: The data used in this study was sourced from the China City Statistical Yearbook from 2001 to 2020. Two indicators were employed to measure medical resources: the number of doctors per million population and the number of hospital and clinic beds per million population. We employed dynamic convergence model and fixed-effects model to examine the correlation between economic growth and the spatial distribution of medical resources. Ordinary least squares (OLS) were used to estimate the ß values of the samples. RESULTS: The average GDP for all city samples across all years was 36,019.31 ± 32,029.36, with an average of 2016.31 ± 1104.16 doctors per million people, and an average of 5986.2 ± 6801.67 hospital beds per million people. In the eastern cities, the average GDP for all city samples was 47,672.71 ± 37,850.77, with an average of 2264.58 ± 1288.89 doctors per million people, and an average of 3998.92 ± 1896.49 hospital beds per million people. Cities with initially low medical resources experienced faster growth (all ß < 0, P < 0.001). The long-term convergence rate of the geographic distribution of medical resources in China was higher than the short-term convergence rate (|ßi + 1| > |ßi|, i = 1, 2, 3, …, 9, all ß < 0, P < 0.001), and the convergence speed of doctor density exceeded that of bed density (bed: |ßi| >doc: |ßi|, i = 3, 4, 5, …, 10, P < 0.001). Economic growth significantly affected the convergence speed of medical resources, and this effect was nonlinear (doc: ßi < 0, i = 1, 2, 3, …, 9, P < 0.05; bed: ßi < 0, i = 1, 2, 3, …, 10, P < 0.01). The heterogeneity between provinces had a notable impact on the convergence of medical resources. CONCLUSIONS: The experiences of China have provided significant insights for nations worldwide. Governments and institutions in all countries worldwide, should actively undertake measures to actively reduce health inequalities. This includes enhancing healthcare standards in impoverished regions, addressing issues of unequal distribution, and emphasizing the examination of social determinants of health within the domain of public health research.

Estimating the impact of different types hearing loss on cognitive decline and the joint effect of hearing loss and depression on cognitive decline among older adults in China.

BACKGROUND: Current research lacks examination of the relationship between different subtypes of hearing loss (HL) and cognitive decline (CD). Additionally, the co-effects of HL and depression on CD remain unexplored. This study aims to investigate the relationship between HL, various types of HL, and CD, as well as the combined impact of HL and depression on CD. METHODS: Data from a total of 5218 older adults who participated in the most recent three waves of Chinese Longitudinal Healthy Longevity Survey (CLHLS) (2011-2012, 2014, and 2018) were included. HL was assessed through self-report and objective measures. CD was defined as a decrease in MMSE score of≥3 between any two survey periods for older adults. Cox proportional hazards model was applied to analyzed. RESULTS: Among Chinese older adults, bilateral HL (HR = 1.202, 95%CI = 1.093-1.322, P < 0.001), onset of HL after the age of 40 (HR = 1.155, 95%CI = 1.056-1.264, P = 0.002), and chronic HL (HR = 1.143, 95%CI = 1.040-1.255, P = 0.005) posed a greater risk. HL (HR = 1.146, 95%CI = 1.048-1.254, P = 0.003) and depression (HR = 1.162, 95%CI = 1.038-1.301, P = 0.009) were independently or jointly associated with CD. Participants who were simultaneously exposed to both HL and depression experienced the highest risk of CD (HR = 1.314, 95%CI = 1.117-1.545, P = 0.001). LIMITATIONS: Given the observational design, unidentified confounding variables may still be present, such as whether to wear a hearing aid. CONCLUSION: This study emphasizes the high risk of specific types of HL for CD and the importance of implementing health interventions that address both physiological and psychological aspects to enhance cognitive function and prevent CD in older adults.

A Complicated Route from Disorder to Order in Antimony-Tellurium Binary Phase Change Materials.

The disorder-to-order (crystallization) process in phase-change materials determines the speed and storage polymorphism of phase-change memory devices. Only by clarifying the fine-structure variation can the devices be insightfully designed, and encode and store information. As essential phase-change parent materials, the crystallized Sb-Te binary system is generally considered to have the cationic/anionic site occupied by Sb/Te atoms. Here, direct atomic identification and simulation demonstrate that the ultrafast crystallization speed of Sb-Te materials is due to the random nature of lattice site occupation by different classes of atoms with the resulting octahedral motifs having high similarity to the amorphous state. It is further proved that after atomic ordering with disordered chemical occupation, chemical ordering takes place, which results in different storage states with different resistance values. These new insights into the complicated route from disorder to order will play an essential role in designing neuromorphic devices with varying polymorphisms.

Association and mediators between the impact of oral health-related quality of life and depression.

OBJECTIVES: Our research intended to explore the association and mediators (perceived social support and sleep quality) between the impact of oral health-related quality of life (OHRQoL) and depression among Chinese older adults. METHODS: A stratified, multi-stage random sampling approach was used in our study. A total of 3896 older individuals aged 60 years and older were included. Process macro 3.5 for SPSS was utilized for testing mediation hypotheses. RESULTS: The mean score of the OHRQoL of the elderly was 3.26 ± 7.15. The correlation coefficient between OHRQoL and depression was 0.25 (p < 0.001). Perceived social support (ß = 0.009, 95% CI = 0.006, 0.012) and sleep quality (ß = 0.073, 95% CI = 0.074, 0.093) mediated the relationship between OHRQoL and depression, respectively. The association between OHRQoL and depression was mediated sequentially by perceived social support and sleep quality (ß = 0.004, 95% CI = 0.002, 0.006). CONCLUSIONS: The participants reported relatively good OHRQoL. OHRQoL and depression showed a significant positive correlation. The relationship between OHRQoL and depression among Chinese seniors was mediated by perceived social support and sleep quality. Both directly and indirectly, OHRQoL can affect depression.

The Relationship between Electron Transport and Microstructure in Ge2Sb2Te5 Alloy.

Phase-change random-access memory (PCRAM) holds great promise for next-generation information storage applications. As a mature phase change material, Ge2Sb2Te5 alloy (GST) relies on the distinct electrical properties of different states to achieve information storage, but there are relatively few studies on the relationship between electron transport and microstructure. In this work, we found that the first resistance dropping in GST film is related to the increase of carrier concentration, in which the atomic bonding environment changes substantially during the crystallization process. The second resistance dropping is related to the increase of carrier mobility. Besides, during the cubic to the hexagonal phase transition, the nanograins grow significantly from ~50 nm to ~300 nm, which reduces the carrier scattering effect. Our study lays the foundation for precisely controlling the storage states of GST-based PCRAM devices.

Economic Evaluation of Cognitive Behavioral Therapy for Depression: A Systematic Review.

OBJECTIVES: This study aimed to conduct a systematic review of cost-utility studies of internet-based and face-to-face cognitive behavioral therapy (CBT) for depression from childhood to adulthood and to examine their reporting and methodological quality. METHODS: A structured search for cost-utility studies concerning CBT for depression was performed in 7 comprehensive databases from their inception to July 2020. Two reviewers independently screened the literature, abstracted data, and assessed quality using the Consolidated Health Economic Evaluation Reporting Standards and Quality of Health Economic Studies checklists. The primary outcome was the incremental cost-effectiveness ratio (ICER) across all studies. To make a relevant comparison of the ICERs across the identified studies, cost data were inflated to the year 2020 and converted into US dollars. RESULTS: Thirty-eight studies were included in this review, of which 26 studies (68%) were deemed of high methodological quality and 12 studies (32%) of fair quality. Despite differences in study designs and settings, the conclusions of most included studies for adult depression were general agreement; they showed that face-to-face CBT monotherapy or combination therapy compared with antidepressants and usual care for adult depression were cost-effective from the societal, health system, or payer perspective (ICER -$241 212.4/quality-adjusted life-year [QALY] to $33 032.47/QALY, time horizon 12-60 months). Internet-based CBT regardless of guided or unguided also has a significant cost-effectiveness advantage (ICER -$37 717.52/QALY to $73 841.34/QALY, time horizon 3-36 months). In addition, CBT was cost-effective in preventing depression (ICER -$23 932.07/QALY to $26 092.02/QALY, time horizon 9-60 months). Nevertheless, the evidence for the cost-effectiveness of CBT for children and adolescents was still ambiguous. CONCLUSIONS: Fair or high-quality evidence showed that CBT monotherapy or combination therapy for adult depression was cost-effective; whether CBT-related therapy was cost-effective for children and adolescents depression remains inconclusive.

Optimization of the In Situ Biasing FIB Sample Preparation for Hafnia-Based Ferroelectric Capacitor.

Hafnia-based ferroelectric (FE) thin films have received extensive attention in both academia and industry, benefitting from their outstanding scalability and excellent CMOS compatibility. Hafnia-based FE capacitors in particular have the potential to be used in dynamic random-access memory (DRAM) applications. Obtaining fine structure characterization at ultra-high spatial resolution is helpful for device performance optimization. Hence, sample preparation by the focused ion beam (FIB) system is an essential step, especially for in situ biasing experiments in a transmission electron microscope (TEM). In this work, we put forward three tips to improve the success rate of in situ biasing experiments: depositing a carbon protective layer to position the interface, welding the sample on the top of the Cu column of the TEM grid, and cutting the sample into a comb-like shape. By these means, in situ biasing of the FE capacitor was realized in TEM, and electric-field-induced tetragonal (t-) to monoclinic (m-) structure transitions in Hf0.5Zr0.5O2 FE film were observed. The improvement of FIB sample preparation technology can greatly enhance the quality of in situ biasing TEM samples, improve the success rate, and extend from capacitor sample preparation to other types.

Rules of hierarchical melt and coordinate bond to design crystallization in doped phase change materials.

While alloy design has practically shown an efficient strategy to mediate two seemingly conflicted performances of writing speed and data retention in phase-change memory, the detailed kinetic pathway of alloy-tuned crystallization is still unclear. Here, we propose hierarchical melt and coordinate bond strategies to solve them, where the former stabilizes a medium-range crystal-like region and the latter provides a rule to stabilize amorphous. The Er0.52Sb2Te3 compound we designed achieves writing speed of 3.2 ns and ten-year data retention of 161 °C. We provide a direct atomic-level evidence that two neighbor Er atoms stabilize a medium-range crystal-like region, acting as a precursor to accelerate crystallization; meanwhile, the stabilized amorphous originates from the formation of coordinate bonds by sharing lone-pair electrons of chalcogenide atoms with the empty 5d orbitals of Er atoms. The two rules pave the way for the development of storage-class memory with comprehensive performance to achieve next technological node.

12-state multi-level cell storage implemented in a 128 Mb phase change memory chip.

128 Mb Phase Change Memory (PCM) chips show potential for many applications in artificial intelligence. A PCM cell often has a sandwich structure that consists of a TiN bottom electrode, a phase change material, and a top metal. TiN films prepared by atomic layer deposition have high thermal stability, and a WN coating layer on the TiN electrode can prevent oxidation in the electric and thermal field, achieving high endurance of the TiN electrode over 1011 cycles. In the phase change material of carbon-doped Ge2Te2Te5 (CGST), C-C chains and C clusters precipitate at the Ge2Te2Te5 (GST) grain boundaries, which effectively refines the grain size of GST. The C confinement enhances the Ge/Sb atomic migration barrier and suppresses the composition segregation in the Reset/Set operation process and the atomic relaxation of the CGST material. As a result, the endurance and conductivity-drift of the PCM chip were enhanced. Finally, stability over 5 × 108 cycles and 12 multi-level stable states were achieved in the 128 Mb PCM chip. This work presents a step towards the realization of large-scale and energy-efficient neuromorphic computing systems.

Correction: 12-state multi-level cell storage implemented in a 128 Mb phase change memory chip.

Correction for '12-state multi-level cell storage implemented in a 128 Mb phase change memory chip' by Zhitang Song et al., Nanoscale, 2021, DOI: 10.1039/d1nr00100k.

Microscopic Mechanism of Carbon-Dopant Manipulating Device Performance in CGeSbTe-Based Phase Change Random Access Memory.

Carbon (C)-doped Ge2Sb2Te5 material is a potential candidate in phase change random access memory (PCRAM) because of its superb thermal stability and ultrahigh cycle endurance. Unfortunately, the role and distribution evolution of C-dopant is still not fully understood, especially in practical industrial devices. In this report, with the aid of advanced spherical aberration corrected transmission electron microscopy, the mechanism of microstructure evolution manipulated by C-dopant is clearly defined. The grain-inner C atoms distinctly increase cationic migration energy barriers, which is the fundamental reason for promoting the thermal stability of metastable face-centered-cubic phase and postponing its transition to the hexagonal structure. By current pulses stimulation, the stochastic grain-outer C clusters tend to aggregate in the active area by breaking C-Ge bonding; thus, grain growth and elemental segregation are effectively suppressed to improve device reliability, for example, lower SET resistance, shorter SET time, and enlarged RESET/SET ratio. In short, the visual distribution variations of C-dopant can manipulate the performance of the PCRAM device, having much broader implications for optimizing its microstructure transition and understanding C-doped material system.

Crystal-Like Glassy Structure in Sc-Doped BiSbTe Ensuring Excellent Speed and Power Efficiency in Phase Change Memory.

Phase change memory (PCM) is regarded as a promising technology for storage-class memory and neuromorphic computing, owing to the excellent performances in operation speed, data retention, endurance, and controllable crystallization dynamics, whereas the high power consumption of PCM remains to be a short-board characteristic that limits its extensive applications. Here, Sc-doped Bi0.5Sb1.5Te3 has been proposed for high-speed and low-power PCM applications. An operation speed of 6 ns and a threshold current of 0.7 mA have been achieved in 190 nm Sc0.23Bi0.5Sb1.5Te3 PCM, which consumes lower power than GeSbTe and ScSbTe PCM. A good endurance of 5 × 105 has been achieved, which is attributed to the small volume change of 4% during phase change and a good homogeneity phase in the crystalline state. The structure of amorphous Sc0.23Bi0.5Sb1.5Te3 has been characterized by experimental and theoretical methods, showing the existence of a large amount of crystal-like structural factions, which can efficiently minimize the atomic movements required for crystallization and subsequently improve the operation speed and power efficiency. The low diffusivity of Sc and Bi at room temperature and the rapidly increased diffusivity of Bi at elevated temperatures are fundamental for the high data retention of 94 °C and the fast crystallization in Sc0.23Bi0.5Sb1.5Te3. The combination of high atomic mobility and minimized atomic movements during crystallization ensures the high speed and low power consumption of Sc0.23Bi0.5Sb1.5Te3 PCM, which can promote its application to energy-efficient systems, that is, AI chips and wearable electronics.

Surface Energy Driven Liquid-Drop-Like Pseudoelastic Behaviors and In Situ Atomistic Mechanisms of Small-Sized Face-Centered-Cubic Metals.

The elastic strain of conventional metals is usually below ∼1%. As the metals' sizes decrease to approximate a few nanometers, their elastic strains can approach ∼8%, and they usually exhibit pseudoelastic strain that can be as large as ∼35%. Previous studies suggested that the pseudoelastic behaviors of nanocrystals were attributed to distinctive mechanisms, including the release of stored elastic energies, the temperature-enhanced surface diffusion, etc. However, the atomistic mechanisms remain elusive. In this study, through large numbers of in situ atomic-scale tensile-fracture experiments, we report liquid-drop-like pseudoelastic behaviors of face-centered-cubic fractured single-crystalline nanowires with diameters varying from 0.5 to 2.2 nm. The ultralarge liquid-drop-like pseudoelastic strain ranged from 31.4% to 81.0% after the nanowire fracture was observed. The in situ atomic-scale investigations revealed that the atomistic mechanisms resulted from surface energy driven plastic deformation including surface diffusion mixed with shear plastic deformation as well as the release of true elastic energy. As the nanowires' diameters decrease below a critical value, the surface pressure can approach the ideal strength of metals. This ultralarge surface pressure drives atoms to diffuse mixed with dislocation nucleation/propagation, which ultimately leads to the fractured nanowires exhibiting liquid-drop-like pseudoelastic phenomena.