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Reconfigurable intelligent surface (RIS) can be employed in a cell-free system to create favorable propagation conditions from base stations (BSs) to users via configurable elements. However, prior works on RIS-aided cell-free system designs mainly rely on the instantaneous channel state information (CSI), which may incur substantial overhead due to extremely high dimensions of estimated channels. To mitigate this issue, a low-complexity algorithm via the two-timescale transmission protocol is proposed in this paper, where the joint beamforming at BSs and RISs is facilitated via alternating optimization framework to maximize the average weighted sum-rate. Specifically, the passive beamformers at RISs are optimized through the statistical CSI, and the transmit beamformers at BSs are based on the instantaneous CSI of effective channels. In this manner, a closed-form expression for the achievable weighted sum-rate is derived, which enables the evaluation of the impact of key parameters on system performance. To gain more insights, a special case without line-of-sight (LoS) components is further investigated, where a power gain on the order of $\mathcal {O}(M)$ is achieved, with $M$ being the BS antennas number. Numerical results validate the tightness of our derived analytical expression and show the fast convergence of the proposed algorithm. Findings illustrate that the performance of the proposed algorithm with two-timescale CSI is comparable to that with instantaneous CSI in low or moderate SNR regime. The impact of key system parameters such as the number of RIS elements, CSI settings and Rician factor is also evaluated. Moreover, the remarkable advantages from the adoption of the cell-free paradigm and the deployment of RISs are demonstrated intuitively. [ABSTRACT FROM AUTHOR]

Pt rare-earth (RE) compounds such as Pt 5 Y have shown great promise as cathode catalysts and can act as strengthening phases in Pt-based alloys as well. The Pt 5 Y was reported to have three different structures but only the Cu 5 Ca-type structure has been elucidated in detail. Here, the atomic structure of another type Pt 5 Y phase in a Pt-Ir-Hf-Y alloy was characterized by transmission electron microscopy (TEM) techniques. Based on the electron diffraction, atomic-scale resolution Z-contrast imaging and elemental mapping results, we proposed a structural model of the Pt 5 Y phase. The ideal structure can be composed of alternating Cu 5 Ca-type sandwich layers and close-packed Pt layers, resulting in a trigonal structure, a = b =5.26 Å, c =26.32 Å, α = β =90° and γ =120° with R32 space group. The finding of the new phase can help us to understand the microstructures of Pt-RE compounds and develop their potential application. [Display omitted] [ABSTRACT FROM AUTHOR]

Reconfigurable intelligent surface (RIS) is a promising solution to build a programmable wireless environment with reconfigurable passive elements, which can achieve high spectral and energy efficiency. In this paper, we investigate the ergodic capacity of RIS-assisted multi-user multiple-input single-output (MISO) wireless systems in both uplink and downlink scenarios. Unlike most of prior works, where instantaneous channel state information (CSI) is assumed, we consider the realistic scenario with only statistical CSI. For both scenarios, we first present an analytical expressions for the ergodic sum capacity of the system. Based on which, the joint power control (or transmit beamforming) and phase shift design problem maximizing the ergodic sum capacity is formulated. Capitalizing on the alternating direction method of multipliers (ADMM), fractional programming (FP) and alternating optimization (AO) methods, efficient suboptimal solutions are obtained for the non-convex design problems. Simulation results are presented to validate the accuracy of the analytical ergodic sum capacity expressions and evaluate the impact of key system parameters such as CSI, Rician $K$ factor, number of RIS elements, and RIS location on the ergodic capacity performance. The findings suggest that the proposed statistical CSI design achieves decent performance compared with the instantaneous CSI based design. Moreover, a signal hot spot can be created when placing the RIS close to the users. [ABSTRACT FROM AUTHOR]

Fracture to fifth metatarsal's base is one the most common injury experienced at the foot. Studies have for long debated the use of operative and non-operative interventions for the management of the fracture, especially owing to its peculiar vasculature. However, to date, no attempt has been made to synthesize the evidence comparing the efficacy of operative and non-operative interventions for managing the fifth metatarsal's base fracture. To meta-statistically compare the effects of operative and non-operative management of fifth metatarsal base fracture. A systematic identification of literature was performed according to PRISMA guidelines on four academic databases: MEDLINE, Scopus, EMBASE, and CENTRAL. A meta-analysis evaluated the influence of operative and non-operative interventions on rate of non-union, mean duration of union, duration of return to activity, duration of return to sport, visual analog scale, and the American orthopedic foot & ankle scale. Out of 1,170 records, 11 articles including 404 participants (mean age: 29.8 ± 7.4 years) were included in this review. This systematic review presents a 1b level of evidence supporting the use of operative interventions for enhancing fracture union as compared to non-operative interventions. The meta-analysis reveals beneficial effects for operative interventions by demonstrating medium to large effect reduction of rate of non-union (Hedge's g: -0.66), duration of union (-1.7), duration of return to activity (-2.07), visual analog scale (-0.86), and enhancement of the American orthopedic foot & ankle scale score (0.73) as compared to non-operative intervention. The current systematic review and meta-analysis recommend the use of operative interventions for managing the fifth metatarsal's base fracture. The review reports beneficial effects of operative interventions as compared to non-operative interventions for reducing the rate of non-union, duration of union, duration of return to activity, duration of return to sport, visual analog scale, and increasing the American orthopedic foot & ankle scale score. [ABSTRACT FROM AUTHOR]

Molybdenum-dependent nitrogenases catalyze the transformation of dinitrogen into ammonia under ambient conditions. The active site (FeMo cofactor) is the structurally and electronically complex weak-field metal cluster [MoFe7S9C] built of Fe4S3 and MoFe3S3C portions connected by three sulfur bridges and containing an interstitial carbon atom centered in an Fe6 trigonal prism. Chemical synthesis of this cluster is a major challenge in biomimetic inorganic chemistry. One synthetic approach of core ligand metathesis has been developed based on the design and synthesis of unprecedented incomplete ([(Tp*)WFe2S3Q3]-) and complete ([(Tp*)WFe3S3Q4]2-) cubane-type clusters containing bridging halide (Q = halide). These clusters are achieved by template-assisted assembly in the presence of sodium benzophenone ketyl reductant; products are controlled by reaction stoichiometry. Incomplete cubane clusters are subject to a variety of metathesis reactions resulting in substitution of a μ2-bridging ligand with other bridges such as N3-, MeO-, and EtS-. Reactions of complete cubanes with Me3SiN3 and S8 undergo a redox metathesis process and lead to core ligand displacement and formation of [(Tp*)WFe3S3(μ3-Q)Cl3]- (Q = Me3SiN2-, S2-). This work affords entry to a wide variety of heteroleptic clusters derivable from incomplete and complete cubanes; examples are provided. Among these is the cluster [(Tp*)WFe3S3(μ3-NSiMe3)Cl3]-, one of the very few instances of a synthetic Fe-S cluster containing a light atom (C, N, O) in the core, which constitutes a close mimic of the [MoFe3S3C] fragment in FeMo cofactor. Superposition of them and comparison of metric information disclose a clear structural relationship [Tp* = tris(3,5-dimethyl-1-pyrazolyl)hydroborate(1-)]. [ABSTRACT FROM AUTHOR]

Abstract: To improve the ability of detecting anomaly intrusions, a combined algorithm is proposed based on Partial Least Square (PLS) feature extraction and Core Vector Machine (CVM) algorithms. Principal elements are firstly extracted from the data set using the feature extraction of PLS algorithm to construct the feature set, and then the anomaly intrusion detection model for the feature set is established by virtue of the speediness superiority of CVM algorithm in processing large-scale sample data. Finally, anomaly intrusion actions are checked and judged using this model. Experiments based on KDD99 data set verify the feasibility and validity of the combined algorithm. [Copyright &y& Elsevier]

Using microdata from the Chinese General Social Survey (CGSS 2010), this paper investigates whether there are green returns to education in China, where educational attainment promotes pro-environmental attitudes and behaviors. We establish causality by exploiting the exogenous variation induced by the implementation of the Compulsory Schooling Law (CSL) in China. We find evidence that educational attainment is associated with higher levels of pro-environmental attitudes and behaviors, and these estimates are robust to various robustness checks. Further analysis reveals that the acquisition of environmental knowledge is the channel that drives the effect of education on pro-environmental attitudes and behaviors. Finally, the effects of education are heterogeneous across individuals. [ABSTRACT FROM AUTHOR]

Background: The causes of gestational diabetes mellitus (GDM) are still unclear. Recent studies have found that the imbalance of the gut microbiome could lead to disorders of human metabolism and immune system, resulting in GDM. This study aims to reveal the different gut compositions between GDM and normoglycemic pregnant women and find the relationship between gut microbiota and GDM.Methods: Fecal microbiota profiles from women with GDM (n = 21) and normoglycemic women (n = 32) were assessed by 16S rRNA gene sequencing. Fasting metabolic hormone concentrations were measured using multiplex ELISA.Results: Metabolic hormone levels, microbiome profiles, and inferred functional characteristics differed between women with GDM and healthy women. Additionally, four phyla and seven genera levels have different correlations with plasma glucose and insulin levels. Corynebacteriales (order), Nocardiaceae (family), Desulfovibrionaceae (family), Rhodococcus (genus), and Bacteroidetes (phylum) may be the taxonomic biomarkers of GDM. Microbial gene functions related to amino sugar and nucleotide sugar metabolism were found to be enriched in patients with GDM.Conclusion: Our study indicated that dysbiosis of the gut microbiome exists in patients with GDM in the second trimester of pregnancy, and gut microbiota might be a potential diagnostic biomarker for the diagnosis, prevention, and treatment of GDM. [ABSTRACT FROM AUTHOR]

Background: The prevalence of dementia in China, particularly in rural areas, is consistently increasing; however, research on population-attributable fractions (PAFs) of risk factors for dementia is scarce. Methods: We conducted a cross-sectional survey, namely, the China Multicentre Dementia Survey (CMDS) in selected rural and urban areas from 2018 to 2020. We performed face-to-face interviews and neuropsychological and clinical assessments to reach a consensus on dementia diagnosis. Prevalence and weighted PAFs of eight modifiable risk factors (six classical: less childhood education, hearing impairment, depression, physical inactivity, diabetes, and social isolation, and two novels: olfactory decline and being unmarried) for all-cause dementia were estimated. Results: Overall, CMDS included 17,589 respondents aged ≥ 65 years, 55.6% of whom were rural residents. The age- and sex-adjusted prevalence for all-cause dementia was 9.11% (95% CI 8.96–9.26), 5.19% (5.07–5.31), and 11.98% (11.8–12.15) in the whole, urban, and rural areas of China, respectively. Further, the overall weighted PAFs of the eight potentially modifiable risk factors were 53.72% (95% CI 52.73–54.71), 50.64% (49.4–51.89), and 56.54% (55.62–57.46) in the whole, urban, and rural areas of China, respectively. The eight risk factors' prevalence differed between rural and urban areas. Lower childhood education (PAF: 13.92%) and physical inactivity (16.99%) were primary risk factors in rural and urban areas, respectively. Conclusions: The substantial urban–rural disparities in the prevalence of dementia and its risk factors exist, suggesting the requirement of resident-specific dementia-prevention strategies. [ABSTRACT FROM AUTHOR]

Background: Despite the improved access to health services in China, inadequate diagnosis and management of dementia are common issues, especially in rural regions.Objective: The Hubei Memory & Aging Cohort Study was designed as a prospective study in Central China to determine the prevalence, incidence, and risk factors for dementia and mild cognitive impairment (MCI) among urban and rural older adults.Methods: From 2018-2020, participants aged ≥65 years were screened, and data regarding their life behaviors, families, socio-economic status, physical and mental health, social and psychological factors, and cognition were collected. Diagnoses of MCI and dementia were made via consensus diagnosis using the Diagnostic and Statistical Manual of Mental Disorders fourth edition criteria.Results: Of 8,221 individuals who completed their baseline clinical evaluation, 4,449 (54.1%) were women and 3,164 (38.4%) were from remote rural areas (average age: 71.96 years; mean education period: 7.58 years). At baseline, 25.98%(95%confidence interval [CI]: 24.99-26.96) and 7.24%(95%CI: 6.68-7.80) of the participants were diagnosed with MCI and dementia, respectively. Prevalence showed a strong relationship with age. The substantial disparities between rural and urban regions in MCI and dementia prevalence and multiple dementia-related risk factors were revealed. Especially for dementia, the prevalence rate in rural areas was 2.65 times higher than that in urban regions.Conclusion: Our results suggested that public health interventions are urgently needed to achieve equitable diagnosis and management for people living with dementia in the communities across urban and rural areas. [ABSTRACT FROM AUTHOR]

A method is described for the calibration of vertical piezoelectric transducer (PZT) stages using a large range metrological atomic force microscope (LRM-AFM). A vertical PZT stage is mounted onto the system and an optical-flat sample is attached on the top of the PZT stage. The AFM probe is operated in contact mode and used as a null indicator to measure the movement of the optical-flat as it is driven by the PZT stage. As the PZT stage is scanned vertically, the AFM probe is in contact with the test surface without lateral scanning. The displacement of the vertical stage of the LRM-AFM is measured by the integrated laser interferometer, and the corresponding laser interferometer readings and the nominal position of the PZT stage are recorded. This body of data is then used to establish the relationship between the laser interferometer reading and the nominal displacement of the PZT stage. Our results show that this method can be used to calibrate PZT stages up to a range of µ250 m with an expanded uncertainty of less than 5 nm. [ABSTRACT FROM AUTHOR]

Background: Some studies have demonstrated an association between low and high body mass index (BMI) and an increased risk of dementia. However, only a few of these studies were performed in rural areas.Objective: This cross-sectional study investigated the associations between BMI and cognitive impairment among community-dwelling older adults from rural and urban areas.Methods: 8,221 older persons enrolled in the Hubei Memory & Ageing Cohort Study (HMACS) were recruited. Sociodemographic and lifestyle data, comorbidities, physical measurements, and clinical diagnoses of cognitive impairment were analyzed. Logistic regression was performed to assess the associations of BMI categories with cognitive impairment. A series of sensitivity analyses were conducted to test whether reverse causality could influence our results.Results: Being underweight in the rural-dwelling participants increased the risk of cognitive impairment. Being overweight was a protective factor in rural-dwelling participants aged 65-69 years and 75-79 years, whereas being underweight was significantly associated with cognitive impairment (OR, 1.37; 95% CI: 1.03-1.83; p < 0.05). Sensitivity analyses support that underweight had an additive effect on the odds of cognitive impairment and was related to risk of dementia. Interaction test revealed that the differences between urban/rural in the relationship between BMI and cognitive impairment are statistically significant.Conclusion: Associations between BMI and cognitive impairment differ among urban/rural groups. Older people with low BMI living in rural China are at a higher risk for dementia than those living in urban areas. [ABSTRACT FROM AUTHOR]

Au 27.9 Ag 20.3 Cu 51.8 noble metal medium-entropy alloy (MEA) is commercially applied in the electrical contact field due to the unique advantages, such as excellent chemical stability, outstanding electrical property and good processability. However, the low strength brings the poor deformation resistance and wear resistance in service. Herein, the cold deformation and aging treatment were applied to strengthen Au 27.9 Ag 20.3 Cu 51.8 noble metal MEA, and the related evolutions of the microstructure, tensile property, and electrical resistivity were experimentally investigated. The phase formation and strengthening mechanisms were theoretically discussed. The results show that Au 27.9 Ag 20.3 Cu 51.8 MEA is composed of the single-phase face-centered cubic (FCC) solid solution at the initial solution treatment of 750 °C. After the aging at 400 °C for 0.5 h, lamellar discontinuous precipitation (DP), consisting of Cu-rich and Ag-rich phases, forms at the grain boundaries (GBs), and L1 2 -type chemical short-range order (CSRO) precipitates in both the matrix and the Cu-rich phase of DP. After 20% cold deformation, the L1 2 -type CSRO similarly emerges in the matrix. After 20% cold deformation prior to aging at 400 °C for 0.5 h, DP at the GBs and L1 2 -type CSRO in the matrix and the Cu-rich lamellae of DP are observed. The growth kinetics of DP and L1 2 -type CSRO are both slightly promoted by prior cold deformation. Au 27.9 Ag 20.3 Cu 51.8 MEA wire with single-phase FCC sold solution achieves the yield strength of ∼422 MPa. And, 20% cold deformation prior to aging at 400 °C for 0.5 h raises the yield strength of Au 27.9 Ag 20.3 Cu 51.8 MEA wire to a peak value of ∼696 MPa. The solid solution strengthening mechanism invariably offers the largest strength contribution during the cold deformation and aging, the strain and precipitation strengthening mechanisms almost equivalently contribute to the strength improvement. The electrical resistivity maintains stable with a small variation during the cold deformation and aging. The findings in this study can provide insights for strengthening the noble metal HEAs or MEAs via traditional strengthening methods, and theoretically support for tailoring the microstructure and properties of the high-performance noble metal HEAs or MEAs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Pt-15Ir-3Hf-0.5Y alloy with good high-temperature strength and ductility is prepared. • No Pt-Hf precipitates but three types of nanoclusters, clusters containing stacking fault, clusters at 1/2 〈0 1 1〉 dislocation core and clusters with short-range order are observed in the alloy matrix. • The alloy has a strong ageing strengthening effect through more and larger clusters formation. A novel ultra-high temperature Pt-15Ir-3Hf-0.5Y (wt.%) alloy was developed for the first time by high vacuum arc-melting, hot rolling and ageing treatment. The microstructures of the as-cast and hot-rolled and then post-aged samples were investigated. The alloy consists of the (Pt,Ir) 5 Y phase and matrix. Through transmission electron microscopy atomic resolution imaging, three types of nanoclusters, clusters containing stacking fault, clusters at 1/2 〈0 1 1〉 dislocation core and clusters with short-range order were observed in the matrix. The hardness at the ambient temperature of the alloy after hot rolling and ageing treatment was up to 443 HV and the tensile strength at 1500 °C was up to 47.8 MPa. Compared with the solid solution strengthened Pt-Ir binary alloys, the addition of Hf and Y can effectively improve the mechanical properties, which were achieved by introducing the combined effects of nanocluster strengthening and grain boundary strengthening of (Pt,Ir) 5 Y phase. Our findings provided new insights into designing the Pt-based superalloy with high strength and ductility. [ABSTRACT FROM AUTHOR]

A direct phase coherent determination of the absolute frequency of the a15 component in the R(12) 26.0 and b10 component in the R(106) 28.0 transitions in 127I2 at 543 nm has been made at the International Bureau of Weights and Measures. Lasers from the Czech Metrology Institute (Czech Republic), the National Institute of Metrology (China), the Centro Nacional de Metrologia (Mexico), the Standards, Productivity and Innovation Board (Singapore), the Centre for Metrology and Accreditation (Finland), the Danish Institute of Fundamental Metrology (Denmark), the National Physical Laboratory (U.K.), and the International Bureau of Weights and Measures took part. The mean frequency values found are ƒ(a15) = 551 579 856 480.4 kHz, uc =4.8 kHz and ƒ(b10) = 551 580 162 397.1 kHz, uc = 4.6 kHz for the current group of lasers, where uc is the combined standard uncertainty. This constitutes a 30-fold improvement in accuracy for this radiation, which is recommended for the realization of the definition of the meter. If only lasers equipped with an iodine cell temperature control are considered, the group of lasers shows a dispersion of 7 kHz. This value is indicative of the level of reproducibility that can be expected at present for this type of standard. [ABSTRACT FROM AUTHOR]