Physical activity and the osteoarthritis of the knee: A Mendelian randomization study.

Previous studies have reported an association between physical activity and the occurrence and progression of knee osteoarthritis (KOA). However, the existing evidence remains limited and of low-quality. This study aimed to examine the causal relationship between different levels of physical activity and KOA. Instrumental variables, represented by single nucleotide polymorphisms (SNPs), were utilized to capture sedentary behavior, appropriate physical exercise, and excessive physical activity. Aggregated statistics from the UK Biobank genome-wide association study dataset were used to assess the impact of these SNPs on KOA. Causality was estimated using inverse variance weighting (IVW), MR Egger, simple model, weighted median, and weighted model approaches. The stability of the results was assessed through heterogeneity and sensitivity analyses. Mendelian randomization (MR) analysis revealed a strong association between sedentary behavior and KOA, with an odds ratio (OR) of 2.096 (95% CI: 1.506-2.917) and a P value of 1.14 × 10-5. Appropriate physical exercise behavior exhibited a strong negative association with KOA, with an OR of 0.147 (95% CI: 0.037-0.582) and a P value of 0.006. Conversely, excessive physical activity behavior showed a significant positive association with KOA, with an OR of 2.162 (95% CI: 1.327-3.521) and a P value of .002. Our findings indicate that sedentary behavior and excessive physical activity are identified as risk factors for KOA, whereas engaging in appropriate physical exercise emerges as a protective factor against the development of KOA.

Clinical phenotypes of comorbidities in end-stage knee osteoarthritis: a cluster analysis.

OBJECTIVES: Comorbidities, as components of these heterogeneous features, often coexist with knee osteoarthritis, and are particularly prevalent in end-stage knee osteoarthritis. Here, we attempted to identify the different clinical phenotypes of comorbidities in patients with end-stage knee osteoarthritis by cluster analysis. METHODS: A total of 421 inpatients diagnosed with end-stage knee osteoarthritis who underwent inpatient surgery were included in this cross-sectional study. 23 demographic, comorbidity, inflammatory immune and evaluation scale variables were collected. Systematic clustering after factor analysis and separate two-step cluster analysis were performed for individual comorbidity variables and all variables, respectively, to objectively identify the different clinical phenotypes of the study patients. RESULTS: Four clusters were finally identified. Cluster 1 had the largest proportion of obese patients (93.8%) and hypertension was common (71.2%). Almost all patients in cluster 2 were depressed (95.8%) and anxiety disorders (94.7%). Cluster 3 combined patients with isolated end-stage knee osteoarthritis and a few comorbidities. Cluster 4 had the highest proportion of patients with rheumatoid arthritis (58.8%). CONCLUSIONS: Patients with end-stage knee osteoarthritis may be classified into four different clinical phenotypes: "isolated end-stage knee osteoarthritis"; "obesity + hypertension"; "depression + anxiety"; and "rheumatoid arthritis", which may help guide individualized patient care and treatment strategies.

Fabrication of Hierarchical Layer-by-Layer Assembled Diamond-based Core-Shell Nanocomposites as Highly Efficient Dye Absorbents for Wastewater Treatment.

The effective chemical modification and self-assembly of diamond-based hierarchical composite materials are of key importance for a broad range of diamond applications. Herein, we report the preparation of novel core-shell diamond-based nanocomposites for dye adsorption toward wastewater treatment through a layer-by-layer (LbL) assembled strategy. The synthesis of the reported composites began with the carboxyl functionalization of microdiamond by the chemical modification of diamond@graphene oxide composite through the oxidation of diamond@graphite. The carboxyl-terminated microdiamond was then alternatively immersed in the aqueous solution of amine-containing polyethylenimine and carboxyl-containing poly acrylic acid, which led to the formation of adsorption layer on diamond surface. Alternating (self-limiting) immersions in the solutions of the amine-containing and carboxyl-containing polymers were continued until the desired number of shell layers were formed around the microdiamond. The obtained core-shell nanocomposites were successfully synthesized and characterized by morphological and spectral techniques, demonstrating higher surface areas and mesoporous structures for good dye adsorption capacities than nonporous solid diamond particles. The LbL-assembled core-shell nanocomposites thus obtained demonstrated great adsorption capacity by using two model dyes as pollutants for wastewater treatment. Therefore, the present work on LbL-assembled diamond-based composites provides new alternatives for developing diamond hybrids as well as nanomaterials towards wastewater treatment applications.

Study of the competitive mechanisms of cyclohexane dehydrogenation by gas-phase Ni2(+) cationic dimer: one-face dehydrogenation versus flip dehydrogenation.

The mechanism of cyclohexane dehydrogenation catalyzed by the cationic dimer Ni2 (+) has been investigated at the B3LYP level of density functional theory. The first dehydrogenation occurs readily (it is exothermic by 30 kcal/mol), whereas the second and third dehydrogenations show weaker exothermicity than the first (23 and 21 kcal/mol, respectively). These three hydrogenations corresponding to the total dehydrogenation of one face of cyclohexane mainly proceed in the doublet state due to the presence of significant minimum-energy crossing points (MECPs). In addition, because the elimination of non-negligible amounts of [H2,2D2] and [2H2,D2] in this reaction was also observed in a previous experiment, we calculated a flip mechanism which would yield results that agree with those experimental results. This flip process includes two MECPs, meaning that the reaction mainly proceeds along the doublet potential energy surface but finishes in the quartet state. The rate-limiting step ((2)IM9 → (2)TS9/10 → (2)IM10) of the flip process is endothermic by 3 kcal/mol and the barrier to this step is 33 kcal/mol. Our calculations indicate that one-face dehydrogenation is a more favorable channel than the flip one. We excluded the possibility that eliminations of [H2,2D2] or [D2,2H2] could proceed through a mechanism involving Ni2 (+) dissociation, or that [H-D] scrambling could occur through (2)TS11/13 ((4)TS12/15), due to the large amounts of energy required. In the dissociation of (2)IM19, (2)[(H2)Ni2(C6H6)](+), a molecule of hydrogen first dissociates, leaving a final product of (2)[Ni2(C6H6)](+). Neither C6H6 nor (H2)Ni2 (+) can easily dissociate from (2)IM19 due to π backdonation.