A wide star-black-hole binary system from radial-velocity measurements.

All stellar-mass black holes have hitherto been identified by X-rays emitted from gas that is accreting onto the black hole from a companion star. These systems are all binaries with a black-hole mass that is less than 30 times that of the Sun1-4. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star-black-hole binaries5,6. When the black hole is not accreting gas, it can be found through radial-velocity measurements of the motion of the companion star. Here we report radial-velocity measurements taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Hα emission line require the presence of a dark companion with a mass of [Formula: see text] solar masses, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. Gravitational-wave experiments have detected black holes of similar mass, but the formation of such massive ones in a high-metallicity environment would be extremely challenging within current stellar evolution theories.

Melatonin is a potential novel analgesic agent for osteoarthritis: Evidence from cohort studies in humans and preclinical research in rats.

Melatonin exhibits potential for pain relief and long-term safety profile. We examined the analgesic effects of oral melatonin on osteoarthritis (OA) and investigated the underlying mechanism. Using data from a UK primary care database, we conducted a cohort study in individuals with OA to compare the number of oral analgesic prescriptions and the risk of knee/hip replacement between melatonin initiators and hypnotic benzodiazepines (i.e., active comparator) initiators using quantile regression models and Cox-proportional hazard models, respectively. To elucidate causation, we examined the effects of melatonin on pain behaviors and explored several metabolites that may serve as potential regulatory agents of melatonin in the monoiodoacetate rat model of OA. Using data from another community-based cohort study, that is, the Xiangya OA Study, we verified the association between the key serum metabolite and incident symptomatic knee OA. Compared with the hypnotic benzodiazepines cohort (n = 8135), the melatonin cohort (n = 813) had significantly fewer subsequent prescriptions of oral analgesics (50th percentile: 5 vs. 7, 75th percentile: 19 vs. 29, and 99th percentile: 140 vs. 162) and experienced a lower risk of knee/hip replacement (hazard ratio = 0.47, 95% Cl: 0.30-0.73) during the follow-up period. In rats, oral melatonin alleviated pain behaviors and increased serum levels of glycine. There was an inverse association between baseline serum glycine levels and the risk of incident symptomatic knee OA in humans (n = 760). In conclusion, our findings indicate that oral melatonin shows significant potential to be a novel treatment for OA pain. The potential role of glycine in its analgesic mechanism warrants further investigation.

Molecular insight into the potential functional role of pseudoenzyme GFOD1 via interaction with NKIRAS2.

The glucose-fructose oxidoreductase/inositol dehydrogenase/rhizopine catabolism protein (Gfo/Idh/MocA) family includes a variety of oxidoreductases with a wide range of substrates that utilize NAD or NADP as redox cofactor. Human contains two members of this family, namely glucose-fructose oxidoreductase domain-containing protein 1 and 2 (GFOD1 and GFOD2). While GFOD1 exhibits low tissue specificity, it is notably expressed in the brain, potentially linked to psychiatric disorders and severe diseases. Nevertheless, the specific function, cofactor preference, and enzymatic activity of GFOD1 remain largely unknown. In this work, we find that GFOD1 does not bind to either NAD or NADP. Crystal structure analysis unveils that GFOD1 exists as a typical homodimer resembling other family members, but lacks essential residues required for cofactor binding, suggesting that it may function as a pseudoenzyme. Exploration of GFOD1-interacting partners in proteomic database identifies NK-κB inhibitor-interacting Ras-like 2 (NKIRAS2) as one potential candidate. Co-immunoprecipitation (co-IP) analysis indicates that GFOD1 interacts with both GTP- and GDP-bound forms of NKIRAS2. The predicted structural model of the GFOD1-NKIRAS2 complex is validated in cells using point mutants and shows that GFOD1 selectively recognizes the interswitch region of NKIRAS2. These findings reveal the distinct structural properties of GFOD1 and shed light on its potential functional role in cellular processes.

Research Progress on Ti3C2Tx-Based Composite Materials in Antibacterial Field.

The integration of two-dimensional Ti3C2Tx nanosheets and other materials offers broader application options in the antibacterial field. Ti3C2Tx-based composites demonstrate synergistic physical, chemical, and photodynamic antibacterial activity. In this review, we aim to explore the potential of Ti3C2Tx-based composites in the fabrication of an antibiotic-free antibacterial agent with a focus on their systematic classification, manufacturing technology, and application potential. We investigate various components of Ti3C2Tx-based composites, such as metals, metal oxides, metal sulfides, organic frameworks, photosensitizers, etc. We also summarize the fabrication techniques used for preparing Ti3C2Tx-based composites, including solution mixing, chemical synthesis, layer-by-layer self-assembly, electrostatic assembly, and three-dimensional (3D) printing. The most recent developments in antibacterial application are also thoroughly discussed, with special attention to the medical, water treatment, food preservation, flexible textile, and industrial sectors. Ultimately, the future directions and opportunities are delineated, underscoring the focus of further research, such as elucidating microscopic mechanisms, achieving a balance between biocompatibility and antibacterial efficiency, and investigating effective, eco-friendly synthesis techniques combined with intelligent technology. A survey of the literature provides a comprehensive overview of the state-of-the-art developments in Ti3C2Tx-based composites and their potential applications in various fields. This comprehensive review covers the variety, preparation methods, and applications of Ti3C2Tx-based composites, drawing upon a total of 171 English-language references. Notably, 155 of these references are from the past five years, indicating significant recent progress and interest in this research area.

The role of B-cell ferroptosis in the pathogenesis of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the dysregulation of B cell subpopulation and function. Recent studies have suggested a potential role of ferroptosis, an iron-dependent form of regulated cell death, in the pathogenesis of SLE. Here, we demonstrate that B-cell ferroptosis occurs both in lupus patients and MRL/lpr mice. Treatment with liproxstatin-1, a potent ferroptosis inhibitor, could reduce autoantibody production, improve renal damage, and alleviate lupus symptoms in vivo. Furthermore, our results suggest that ferroptosis may regulate B cell differentiation and plasma cell formation, indicating a potential mechanism for its involvement in SLE. Taken together, targeting ferroptosis in B cells may be a promising therapeutic strategy for SLE.

Effective method for low-light image enhancement based on the JND and OCTM models.

Low-light images always suffer from dim overall brightness, low contrast, and low dynamic ranges, thus result in image degradation. In this paper, we propose an effective method for low-light image enhancement based on the just-noticeable-difference (JND) and the optimal contrast-tone mapping (OCTM) models. First, the guided filter decomposes the original images into base and detail images. After this filtering, detail images are processed based on the visual masking model to enhance details effectively. At the same time, the brightness of base images is adjusted based on the JND and OCTM models. Finally, we propose a new method to generate a sequence of artificial images to adjust the brightness of the output, which has a better performance in image detail preservation compared with other single-input algorithms. Experiments have demonstrated that the proposed method not only achieves low-light image enhancement, but also outperforms state-of-the-art methods qualitatively and quantitatively.

Effective enhancement method of low-light-level images based on the guided filter and multi-scale fusion.

Aiming to solve the problem of low-light-level (LLL) images with dim overall brightness, uneven gray distribution, and low contrast, in this paper, we propose an effective LLL image enhancement method based on the guided filter and multi-scale fusion for contrast enhancement and detail preservation. First, a base image and detail image(s) are obtained by using the guided filter. After this procedure, the base image is processed by a maximum entropy-based Gamma correction to stretch the gray level distribution. Unlike the existing methods, we enhance the detail image(s) based on the guided filter kernel, which reflects the image area information. Finally, a new method is proposed to generate a sequence of artificial images to adjust the brightness of the output, which has a better performance in image detail preservation compared with other single-input algorithms. Experiments show that the proposed method can provide a more significant performance in enhancing contrast, preserving details, and maintaining the natural feeling of the image than the state of the art.

Anteromedial Portal Technique, but Not Outside-in Technique, Is Superior to Standard Transtibial Technique in Knee Stability and Functional Recovery After Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis.

PURPOSE: To compare the postoperative outcomes of 4 different femoral drilling techniques in anterior cruciate ligament reconstruction. METHODS: Three databases were searched for randomized controlled trials comparing any 2 or more of the following femoral drilling techniques in anterior cruciate ligament reconstruction: standard transtibial (sTT), anteromedial portal (AMP), outside-in (OI), or modified transtibial (mTT) technique. A Bayesian network meta-analysis was performed to assess postoperative stability and functional recovery in terms of the side-to-side difference (measured by arthrometry), Lachman test, pivot-shift test, International Knee Documentation Committee subjective and objective scores, Lysholm score, and Tegner score. The Fisher exact probability test and χ2 test were used to compare the incidences of infection and graft rupture, respectively. RESULTS: We included 20 randomized controlled trials involving 1,515 patients. The AMP technique showed a lower side-to-side difference (standardized mean difference, -0.33; 95% credible interval [CrI], -0.53 to -0.12), higher negative rate on the pivot-shift test (odds ratio, 2.19; 95% CrI, 1.38 to 3.44), and higher International Knee Documentation Committee objective score (odds ratio, 3.13; 95% CrI, 1.42 to 7.82) than the sTT technique. However, knee stability and functional outcomes did not differ significantly between the OI and sTT techniques. Safety outcomes of the mTT technique were unavailable. The incidence of graft rupture was 5.20% for the OI technique, 2.27% for the AMP technique, and 1.51% for the sTT technique. The OI technique had a significantly higher incidence of graft rupture than the sTT technique (χ2 = 4.421, P = .035). No significant difference in the incidence of infection was found between the sTT, AMP, and OI techniques (P = .281). CONCLUSIONS: The AMP technique, but not the OI technique, was superior to the sTT technique in knee stability and functional recovery. The OI technique had a higher incidence of graft rupture than the sTT technique. There was no significant difference between the AMP and OI techniques or between the mTT technique and any other femoral drilling technique. LEVEL OF EVIDENCE: Level II, meta-analysis of Level I and II studies.

Prevalence and distribution of ultrasound-detected hand synovial abnormalities in a middle-aged and older population.

OBJECTIVE: Synovial abnormalities are modifiable targets for hand pain and osteoarthritis. We examined the prevalence and distribution of ultrasound-detected hand synovial abnormalities in a community-derived sample of older people in China. METHODS: Within the Xiangya Osteoarthritis Study, a community-based study, we assessed synovial hypertrophy (SH), joint effusion, and Power Doppler signal (PDS) on all fingers and thumbs of both hands using standardized ultrasound examinations (score: 0-3). We assessed distribution patterns of SH and effusion using χ2-test and interrelationships of SH and effusion in different joints and hands by generalized estimating equations. RESULTS: Among 3,623 participants (mean age: 64.4 years; women: 58.1%), prevalence of SH, effusion and PDS were 85.5%, 87.3% and 1.5%, respectively. Prevalence of SH, effusion and PDS increased with age, was higher in the right hand than in the left hand and was more common in proximal than in distal hand joints. SH and effusion often occurred in multiple joints (P < 0.001). SH in one joint was strongly associated with presence of SH in the same joint of the opposite hand (odds ratio [OR]= 6.60, 95% confidence interval [CI]: 6.19-7.03) followed by SH in other joints in the same row, (OR=5.70, 95%CI: 5.32-6.11), and then other joints in the same ray of the same hand (OR=1.49, 95%CI: 1.39-1.60). Similar patterns were observed for effusion. CONCLUSION: Hand synovial abnormalities are common among older people, often affect multiple hand joints and present a unique pattern. These findings suggest both systemic and mechanical factors play roles in their occurrence.

Intra-Articular Magnesium Plus Bupivacaine Is the Most Effective and Safe Postoperative Analgesic Option Following Knee Arthroscopy: A Network Meta-analysis.

PURPOSE: To evaluate the comparative efficacy and safety of single-dose intra-articular injection of commonly used analgesics after knee arthroscopy. METHODS: A systematic literature review was done to search for randomized controlled trials (RCTs) published from database inception to October 1, 2020, that compared analgesics (i.e., morphine, bupivacaine, ropivacaine, and magnesium alone or in combination) with placebo or each other after knee arthroscopy. The primary outcomes were postoperative pain intensity at 2 hours and 24 hours. Secondary outcomes included the time to first analgesic request, number of patients requiring supplementary analgesics and side effects. We estimated summary standardized mean differences (SMDs) or odds ratios with 95% credible intervals (95% CrIs) using Bayesian network meta-analysis with random effects. RESULTS: In total, 78 randomized controlled trials comprising 4,425 participants were included. Compared with placebo, magnesium plus bupivacaine was most likely to be effective in relieving pain at both 2-hour (SMD = -3.81, 95% CrI -5.28 to -2.35) and 24-hour after surgery (SMD = -2.81, 95% CrI: -4.29 to -1.30). Following was morphine plus bupivacaine (2-hour: SMD = -2.19, 95% CrI -3.05 to -1.31; 24-hour: SMD = -1.44, 95% CrI -2.14 to -0.73) and bupivacaine alone (2-hour: SMD = -1.66, 95% CrI -2.33 to -0.98; 24-hour: SMD = -0.67, 95% CrI -1.22 to -0.07); ropivacaine alone and magnesium alone were not effective on pain relief. The interval time to first analgesic request was significantly extended compared with placebo except for ropivacaine alone and magnesium alone. The number of patients requiring supplementary analgesics was reduced in all groups except ropivacaine alone. No statistically significant difference was found between any studied analgesics or placebo with regard to side effects. CONCLUSIONS: Of 6 common postoperative intra-articular analgesics, magnesium plus bupivacaine provides the most effective pain relief without increasing short-term side effects after knee arthroscopy. LEVEL OF EVIDENCE: Level II, meta-analysis of Level I and II studies.

Immunomodulatory Effects of Sinensetin on Macrophage and Cyclophosphamide-induced Immunosuppression in Mice.

In this study, we investigated the immunomodulatory effects of sinensetin (SI) on RAW 264.7 macrophages and cyclophosphamide (CY)-induced immunosuppressed mice. The results showed that SI enhanced macrophage activity and promoted the secretion of NO, IL-1ß, and TNF-α in vitro. Compared with the CY-induced immunosuppressed mice, in mice treated with SI, the body weights, organ indices, and total lymphocytes increased. Furthermore, SI promoted the secretion and mRNA expression of IFN-γ, IL-2, and IL-6 and reduced the damage caused by CY to the organs of the immune system. Moreover, it increased the activities of GSH-Px, CAT, SOD, and T-AOC and decreased the level of MDA. This study suggests that SI has the potential to be used as an immunity enhancer in the functional food and healthcare industries.

High-power Si-Ge photodiode assisted by doping regulation.

High-power silicon-based photodiodes are key components in many silicon photonics systems, such as microwave photonics systems, an optical interconnection system with multi-level modulation formats, etc. Usually, the saturation power of the silicon-germanium (Si-Ge) photodiode is limited by the space-charge screening (SCS) effect and the feasibility of the fabrication process. Here, we propose a high saturation power Si-Ge photodiode assisted by doping regulation. Through alleviating the SCS effect of the photodiode, we successfully demonstrate an 85.7% improvement on the saturation power and a 57% improvement on the -1 dB compression photocurrent. The proposed high-power Si-Ge photodiode requires no specific fabrication process and will promote the low-cost integrated silicon photonics systems for more applications.

Optical spatiotemporal differentiator using a bilayer plasmonic grating.

As a key element in wave-based analog computation, optical differentiators have been implemented to directly perform information processing, such as edge detection and pulse shaping, in both spatial and temporal domains. Here, we propose an optical spatiotemporal differentiator, which simultaneously performs first-order spatial and temporal differentiation in transmission by breaking the mirror symmetry of a subwavelength bilayer metal grating. The spatial and temporal performance of the plasmonic differentiator is evaluated numerically using the output field profiles of an optical beam and pulse envelope, showing resolutions of ∼2µm and ∼50fs, respectively. Moreover, the function of spatiotemporal differentiation is demonstrated with input flat-top pulse fields. The proposed optical differentiator has potential applications in ultra-compact real-time optical multifunctional computing systems and parallel signal processing.

Bioinformatic analysis of key biomarkers and immune filtration of skin biopsy in discoid lupus erythematosus.

OBJECTIVE: Discoid lupus erythematosus (DLE) is the most common category of chronic cutaneous lupus erythematosus, where the pathological process is proved to be closely associated with immunity. This bioinformatic analysis sought to identify key biomarkers and to perform immune infiltration analysis in the skin biopsy samples of DLE. METHODS: GSE120809, GSE100093, GSE72535, GSE81071 were used as the data source of gene expression profiles, altogether containing 79 DLE samples and 47 normal controls (NC). Limma package was applied to identify differentially expressed genes (DEGs) and additional Gene Ontology (GO) together with The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were done. Protein-protein interaction network (PPI) was constructed using STRING and Cytoscape. Hub genes were selected by CytoHubba. Finally, immune filtration analysis was finished by the CIBERSORT algorithm, and comparisons between the two groups were accomplished. RESULTS: A total of 391 DEGs were identified, which were composed of 57 up-regulated genes and 334 down-regulated genes. GO and KEGG enrichment analyses revealed that DEGs were closely related with different steps in the immune response. Top 10 hub genes included GBP2, HLA-F, IFIT2, RSAD2, ISG15, IFIT1, IFIT3, MX1, XAF1 and IFI6. Immune filtration analysis from CIBERSORT had found that compared with NC, DLE samples had higher percentages of CD8+ T cells, T cells CD4 memory activated, T cells gamma delta, macrophages M1 and lower percentages of T cells regulatory, macrophages M2, dendritic cells resting, mast cells resting, mast cells activated. CONCLUSION: This bioinformatic study selected key biomarkers from the contrast between DLE and NC skin samples and is the first research to analyze immune cell filtration in DLE.

CPF impedes cell cycle re-entry of quiescent lung cancer cells through transcriptional suppression of FACT and c-MYC.

Blockade of cell cycle re-entry in quiescent cancer cells is a strategy to prevent cancer progression and recurrence. We investigated the action and mode of action of CPF mixture (Coptis chinensis, Pinellia ternata and Fructus trichosanthis) in impeding a proliferative switch in quiescent lung cancer cells. The results indicated that CPF impeded cell cycle re-entry in quiescent lung cancer cells by reduction of FACT and c-MYC mRNA and protein levels, with concomitant decrease in H3K4 tri-methylation and RNA polymerase II occupancy at FACT and c-MYC promoter regions. Animals implanted with quiescent cancer cells that had been exposed to CPF had reduced tumour volume/weight. Thus, CPF suppresses proliferative switching through transcriptional suppression of FACT and the c-MYC, providing a new insight into therapeutic target and intervention method in impeding cancer recurrence.

Statin use and risk of joint replacement due to osteoarthritis and rheumatoid arthritis: a propensity-score matched longitudinal cohort study.

OBJECTIVE: Statins are reported to have a potential benefit on progression of OA and on disease activity in RA, but existing evidence is conflicting. Our objective was to examine whether statins associate with reduction in the risk for joint replacement due to OA and RA. METHODS: This was a propensity score-matched cohort study. Electronic health records from the UK Clinical Practice Research Datalink were used. We selected people prescribed statins and people never prescribed statins. Each statin user was matched to a non-user by age, gender, practice and propensity score for statin prescription. The main outcome measures were knee or hip joint replacement overall, and specifically because of OA or RA. The association between statins and risk of joint replacement was assessed using Cox proportional hazard regression. Statin exposure was categorized according to the potency of reducing low-density lipoprotein as low (21-28%), medium (32-38%) or high (42-55%) intensity. RESULTS: A total of 178 467 statin users were matched with 178 467 non-users by age, gender, practice and propensity score. Overall, statin was not associated with reduced risk of knee or hip replacement (hazard ratio 0.99, 95% CI: 0.97, 1.03), unless prescribed at high strength (0.86, 0.75-0.98). The reduced risk was only observed for joint replacement due to RA (0.77, 0.63-0.94) but not OA (0.97, 0.94-1.01). CONCLUSION: Statins at high intensity may reduce the risk of hip or knee replacement. This effect may be RA specific. Further studies to investigate mechanisms of risk reduction and the impact in people with RA are warranted.

Association Between Dietary Selenium Intake and the Prevalence of Nonalcoholic Fatty Liver Disease: A Cross-Sectional Study.

Objective: The aim was to examine the association between dietary selenium intake and nonalcoholic fatty liver disease (NAFLD) in a large group of middle-aged and elderly Chinese persons.Method: The data included in this analysis were from a population-based study, the Xiangya Hospital Health Management Center Study. NAFLD was diagnosed by (1) imaging or histological evidence of hepatic steatosis; (2) absence of specific etiologies of NAFLD; and (3) no heavy consumption of alcohol. Dietary selenium intake was assessed using a validated semi-quantitative food frequency questionnaire. The association between dietary selenium intake and the prevalence of NAFLD was evaluated using logistic and spline regression in a cross-sectional study of 5436 subjects.Results: The prevalence of NAFLD was 36.8%. Compared with the lowest quintile, the energy-adjusted odds ratios for NAFLD were 1.27 (95% confidence interval [CI], 1.07-1.52), 1.30 (95% CI, 1.09-1.55), and 1.58 (95% CI, 1.33-1.89) for the third, fourth, and fifth quintiles of selenium intake, respectively, and there was a positive dose-response relationship (r = 0.88, p for trend = 0.008). Similar results were observed for men and women separately. The findings were not materially altered by adjustment for potential confounders (i.e., age, gender, body mass index, smoking status, diabetes, hypertension, activity level, nutritional supplements, energy intake, fat intake, fiber intake, cholesterol and saturated fatty acid intake).Conclusions: In this middle-aged and elderly population, subjects with higher dietary selenium intake, even below the recommended nutrient intake in China, had higher prevalence of NAFLD in a dose-response relationship manner.

Using deep learning and Google Street View to estimate the demographic makeup of neighborhoods across the United States.

The United States spends more than $250 million each year on the American Community Survey (ACS), a labor-intensive door-to-door study that measures statistics relating to race, gender, education, occupation, unemployment, and other demographic factors. Although a comprehensive source of data, the lag between demographic changes and their appearance in the ACS can exceed several years. As digital imagery becomes ubiquitous and machine vision techniques improve, automated data analysis may become an increasingly practical supplement to the ACS. Here, we present a method that estimates socioeconomic characteristics of regions spanning 200 US cities by using 50 million images of street scenes gathered with Google Street View cars. Using deep learning-based computer vision techniques, we determined the make, model, and year of all motor vehicles encountered in particular neighborhoods. Data from this census of motor vehicles, which enumerated 22 million automobiles in total (8% of all automobiles in the United States), were used to accurately estimate income, race, education, and voting patterns at the zip code and precinct level. (The average US precinct contains ∼1,000 people.) The resulting associations are surprisingly simple and powerful. For instance, if the number of sedans encountered during a drive through a city is higher than the number of pickup trucks, the city is likely to vote for a Democrat during the next presidential election (88% chance); otherwise, it is likely to vote Republican (82%). Our results suggest that automated systems for monitoring demographics may effectively complement labor-intensive approaches, with the potential to measure demographics with fine spatial resolution, in close to real time.

Association between serum zinc and copper concentrations and copper/zinc ratio with the prevalence of knee chondrocalcinosis: a cross-sectional study.

BACKGROUND: Patients with chondrocalcinosis may suffer from a series of symptoms resembling acute gouty arthritis or septic arthritis, but the aetiology and pathogenesis of chondrocalcinosis have not been fully elucidated yet. This study was aimed to assess serum zinc and copper concentrations, as well as the ratio of serum copper to zinc concentrations (Cu/Zn ratio), in relation to the prevalence of knee chondrocalcinosis. METHODS: Data included in this analysis were retrieved from a large population-based cross-sectional study. A bilateral knee anteroposterior radiograph was obtained from each subject. Radiographic knee chondrocalcinosis was diagnosed if definite linear cartilage calcification was detected. Serum zinc and copper concentrations were measured using the spectrophotometric flow injection methods by Roche modular P800. The relations of serum zinc and copper concentrations and Cu/Zn ratio to the prevalence of knee chondrocalcinosis were examined using generalized estimating equations, respectively. RESULTS: The prevalence of knee chondrocalcinosis was 1.2% in the sample of this study (n = 12,362). In comparison with the lowest tertile, the odds ratios (ORs) of knee chondrocalcinosis adjusted by age, sex and body mass index were 0.74 (95% CI 0.50-1.09) in the second and 0.56 (95% CI 0.36-0.86) in the third tertiles of serum zinc concentrations (P for trend = 0.009), were 1.26 (95% CI 0.77-2.05) in the second and 2.01 (95% CI 1.25-3.24) in the third tertile of serum copper concentrations (P for trend = 0.003), and were 1.02 (95% CI 0.61-1.69) in the second and 2.23 (95% CI 1.38-3.59) in the third tertile of Cu/Zn ratio (P for trend < 0.001) respectively. These findings were not materially altered by adjustment for potential confounders. CONCLUSIONS: The present study observed that higher serum zinc concentrations, lower serum copper concentrations or lower Cu/Zn ratio are associated with a lower prevalence of knee chondrocalcinosis in a dose-response relationship manner.

Physical Distancing Measures and Walking Activity in Middle-aged and Older Residents in Changsha, China, During the COVID-19 Epidemic Period: Longitudinal Observational Study.

BACKGROUND: Physical distancing measures taken to contain COVID-19 transmission may substantially reduce physical activity levels and cause individuals to adopt a more sedentary lifestyle. OBJECTIVE: The objective of this study is to determine if there was any change in daily steps, an important component of daily physical activity, and examine risk factors for frequent low daily steps during the COVID-19 epidemic. METHODS: We used data collected from the Step Study, a population-based longitudinal study of walking activity among residents aged ≥40 years in Changsha, China. Daily steps were collected via a smartphone linked to WeChat, a social networking platform. We plotted mean daily steps and the prevalence of low daily steps (≤1500 steps/day) 30 days before (reference period) and 30 days after (epidemic period) January 21, 2020 (date of the first COVID-19 case diagnosed in Changsha), and compared it with the same corresponding period from 2019. We examined the association of risk factors with the prevalence of frequent low daily steps (≤1500 steps/day for ≥14 days) using logistic regression. RESULTS: Among 3544 participants (mean age 51.6 years; n=1226 females, 34.6%), mean daily steps dropped from 8097 to 5440 and the prevalence of low daily steps increased from 3% (2287/76,136 person-day) to 18.5% (12,951/70,183 person-day) during the reference and epidemic periods, respectively. No such phenomenon was observed during the corresponding period in 2019. Older age (P for interaction=.001) and female sex (P for interaction<.001) were both associated with a higher prevalence of frequent low daily steps and were more pronounced during the epidemic period. More education was associated with a lower prevalence of frequent low daily steps during the reference period but not the epidemic period (P for interaction=.34). Body mass index or comorbidity were not associated with frequent low daily steps during either period. CONCLUSIONS: Daily steps of Changsha residents aged ≥40 years dropped significantly during the COVID-19 period, especially among older adults and females. Although successful physical distancing, measured by the rapid downward trend in daily step counts of residents, played a critical role in the containment of the COVID-19 epidemic, our findings of an increase in the prevalence of frequent low daily steps raise concerns about unintended effects on physical activity.