TONs of copper fun: There is considerable interest in developing catalysts to harness the abundant natural supply of methane for various industrial applications. Two tricopper complexes capable of ...mediating efficient oxidation of methane to methanol under ambient conditions were tested: a biomimetic tricopper complex (see figure) and a tricopper‐peptide species derived from the particulate methane monooxygenase (pMMO) protein.
Methane monooxygenases (MMOs) mediate the facile conversion of methane into methanol in methanotrophic bacteria with high efficiency under ambient conditions. Because the selective oxidation of ...methane is extremely challenging, there is considerable interest in understanding how these enzymes carry out this difficult chemistry. The impetus of these efforts is to learn from the microbes to develop a biomimetic catalyst to accomplish the same chemical transformation. Here, we review the progress made over the past two to three decades toward delineating the structures and functions of the catalytic sites in two MMOs: soluble methane monooxygenase (sMMO) and particulate methane monooxygenase (pMMO). sMMO is a water-soluble three-component protein complex consisting of a hydroxylase with a nonheme diiron catalytic site; pMMO is a membrane-bound metalloenzyme with a unique tricopper cluster as the site of hydroxylation. The metal cluster in each of these MMOs harnesses O2 to functionalize the CH bond using different chemistry. We highlight some of the common basic principles that they share. Finally, the development of functional models of the catalytic sites of MMOs is described. These efforts have culminated in the first successful biomimetic catalyst capable of efficient methane oxidation without overoxidation at room temperature.
Background: Family caregiving is the crucial informal care resource to lessen the burdens associated with dementia. Research in this field has focused on reducing the caregiver's burden, but little ...attention has been given to promoting the positive aspects of caregiving.
Objectives: To conduct a systematic critical review of research on the nature of positive aspects of caregiving, and the factors predicting this phenomenon among family caregivers of dementia patients, with the ultimate purpose of gaining insights to explain how and why it emerges.
Review methods: A systematic search of the literature was undertaken in the databases OvidMedline, CINAHL, PsycINFO, Web of Science and Scopus, using the keywords ‘care* AND Alzheimer OR dementia AND ‘positive aspect' OR ‘positive experience' OR ‘positive perceptions' OR reward OR gain OR ‘satisfaction with care*' OR ‘care* satisfaction' OR benefit OR uplift OR meaning OR enjoyment OR pleasure OR growth OR hope OR gratification. The Critical Appraisal Skills Programme checklists for qualitative and cohort studies were used to evaluate data quality. Narrative data synthesis was undertaken using the five-stage Whittermore and Knafl method.
Results: A total of 3862 articles were identified, of which 41 were included in this review. The key findings are that positive aspects of caregiving among family caregivers of dementia patients form a multi-dimensional construct which covers four key domains: a sense of personal accomplishment and gratification, feelings of mutuality in a dyadic relationship, an increase of family cohesion and functionality, and a sense of personal growth and purpose in life. By integrating the findings about the nature and conditions predicting positive aspects of caregiving, the presence of three conditions was identified as promoting the emergence of such qualities i) personal and social affirmation of role fulfilment, ii) effective cognitive emotional regulation and iii) contexts which favour finding meaning in the caregiving process.
Conclusion: The findings of this review provide insight into catalysing the paradigm shift from ‘reducing stress' to ‘optimising positive experience' in developing caregiving support services for dementia, and may guide future empirical study to explain this unique dimension of caregiving experience.
Individuals with mild cognitive impairment have a heightened risk of developing dementia. Physical exercise, especially moderate-intensity aerobic exercise, is a promising lifestyle intervention to ...improve the cognitive function of this patient group. However, the mechanisms underlying the exercise–cognition relationship are not fully understood. Whether the cognitive benefits of physical exercise can improve the overall well-being of this group remains unknown. This study aims to address these research gaps in the under-researched Chinese population.
This study aimed to evaluate the effects of a moderate-intensity aerobic exercise programme on the cognitive function and health-related quality of life of Chinese elderly with mild cognitive impairment and to explore the mediating roles of depressive mood and sleep quality in the exercise–cognition relationship.
A single-blinded randomised controlled trial.
This study was conducted in two urban community healthcare centres in Hangzhou City, China. Elderly people aged over 60 years screened with mild cognitive impairment were included.
A total of 120 eligible participants were randomly assigned to receive either the group-based moderate-intensity aerobic exercise programme or the health education programme (as attention–placebo control). Montreal Cognitive Assessment, Quality of Life-Alzheimer’s Disease, Geriatric Depression Scale and Pittsburgh Sleep Quality Index were administered at baseline before randomisation and immediately after the completion of the interventions. Analysis followed the intention-to-treat principle. Generalised estimating equation was used to compare the changes in the cognitive function and health-related quality of life over the pre-test and post-test periods between the groups. The mediating roles of depressive mood and sleep quality in the exercise–cognition relationship were examined with the PROCESS macro.
Participants in the intervention group had a significantly greater improvement in terms of cognitive function (β = 1.895; 95% confidential interval CI = 1.421, 2.368; p < 0.001) and health-related quality of life (β= 0.605; 95% CI= 0.295, 0.914; p < 0.001) compared with the control group over the pre-test and post-test periods. The exercise–cognition relationship was significantly mediated by reduced depressive symptoms (indirect effect: β= −0.705; 95% CI: −1.028, −0.382) and improved sleep quality (indirect effect: β=−0.205; 95% CI: −0.122, 0.831).
This study revealed the benefits and outlined the underlying mediating mechanism of an aerobic exercise programme to the cognitive function and health-related quality of life of Chinese elderly people with mild cognitive impairment. The findings provided insights into the development of public health initiatives to promote brain health amongst the elderly with mild cognitive impairment.
There is considerable evidence for relationship between gut microbiota and osteoarthritis (OA), but no studies have investigated their causal relationship.
This study utilized large-scale genome-wide ...association studies (GWAS) summary statistics to evaluate the causal association between gut microbiota and OA risk. Specifically, two-sample Mendelian randomization (MR) approach was used to identify the causal microbial taxa for OA. Comprehensively sensitive analyses were performed to validate the robustness of results and novel multivariable MR analyses were further conducted to ensure the independence of causal association. Reverse-direction MR analyses were performed to rule out the possibility of reverse associations. Finally, enrichment analyses were used to investigate the biofunction.
After correction, three microbial taxa were identified to be causally associated with diverse joint OA (PFDR < 0.100), namely Methanobacteriaceae family for knee OA (PFDR = 0.043) and any OA (PFDR = 0.028), Desulfovibrionales order for knee OA (PFDR = 0.045) and Ruminiclostridium5 genus for knee OA (PFDR = 0.063). In addition, we also identified five suggestive microbial taxa that were significant with three different methods under the nominal significance (P < 0.05). Sensitive analysis excluded the influence of heterogeneity and horizontal pleiotropy and multivariable MR analysis ruled out the possibility of horizontal pleiotropy of BMI. GO enrichment analysis illustrates the protective mechanism of the identified taxa against OA.
This study found that several microbial taxa were causally associated with diverse joint OA. The results enhanced our understanding of gut microbiota in the pathology of OA.
A study of the oxygen reduction reaction (ORR) on a screen printed carbon electrode surface mediated by the tricopper cluster complex Cu3(7‐N‐Etppz(CH2OH)) dispersed on electrochemically reduced ...carbon black, where 7‐N‐Etppz(CH2OH) is the ligand 3,3′‐(6‐(hydroxymethyl)‐1,4‐diazepane‐1,4‐diyl)bis(1‐(4‐ethyl piperazin‐1‐yl)propan‐2‐ol), is described. Onset oxygen reduction potentials of about 0.92 V and about 0.77 V are observed at pH 13 and pH 7 vs. the reversible hydrogen electrode, which are comparable to the best values reported for any synthetic copper complex. Based on half‐wave potentials (E1/2), the corresponding overpotentials are about 0.42 V and about 0.68 V, respectively. Kinetic studies indicate that the trinuclear copper catalyst can accomplish the 4 e− reduction of O2 efficiently and the ORR is accompanied by the production of only small amounts of H2O2. The involvement of the copper triad in the O2 activation process is also verified.
Involvement of a synthetic copper triad in binding and reduction of O2 is demonstrated. The presence of the third Cu ion is crucial to supplying the third reducing equivalent for O−O bond cleavage and reduces the overpotential.
Phytochemicals have been used as potential chemopreventive or chemotherapeutic agents. However, there are data suggesting a mutagenic effect of some phytochemicals. We hypothesized that safrole would ...have anticancer effects on human oral squamous cell carcinoma HSC-3 cells. Safrole decreased the percentage of viable HSC-3 cells via induction of apoptosis by an increased level of cytosolic Ca2+ and a reduction in the mitochondrial membrane potential (ΔΨ
m
). Changes in the membrane potential were associated with changes in the Bax, release of cytochrome c from mitochondria, and activation of downstream caspases-9 and -3, resulting in apoptotic cell death. In vivo studies also showed that safrole reduced the size and volume of an HSC-3 solid tumor on a xenograft athymic nu/nu mouse model. Western blotting and flow cytometric analysis studies confirmed that safrole-mediated apoptotic cell death of HSC-3 cells is regulated by cytosolic Ca2+ and by mitochondria- and Fas-dependent pathways.
With the aim of gathering temporal trends on bacterial epidemiology and resistance from multiple laboratories in China, the CHINET surveillance system was organized in 2005. Antimicrobial ...susceptibility testing was carried out according to a unified protocol using the Kirby-Bauer method or automated systems. Results were analyzed according to Clinical and Laboratory Standards Institute (CLSI) 2014 definitions. Between 2005 and 2014, the number of bacterial isolates ranged between 22 774 and 84 572 annually. Rates of extended-spectrum β-lactamase production among Escherichia coli isolates were stable, between 51.7 and 55.8%. Resistance of E. coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, piperacillin/tazobactam and cefoperazone/sulbactam decreased with time. Carbapenem resistance among K. pneumoniae isolates increased from 2.4 to 13.4%. Resistance of Pseudomonas aeruginosa strains against all of antimicrobial agents tested including imipenem and meropenem decreased with time. On the contrary, resistance of Acinetobacter baumannii strains to carbapenems increased from 31 to 66.7%. A marked decrease of methicillin resistance from 69% in 2005 to 44.6% in 2014 was observed for Staphylococcus aureus. Carbapenem resistance rates in K. pneumoniae and A. baumannii in China are high. Our results indicate the importance of bacterial surveillance studies.
Summary
Background Nationwide data on the epidemiology of dermatomyositis (DM) and polymyositis (PM) were limited.
Objectives This study was to estimate the incidence, occurrence of cancer and ...mortality of DM and PM in Taiwan.
Methods Both the register of critical illness of the Taiwan National Health Insurance Research Dataset and the National Death Registry of Taiwan were used to calculate estimates of the incidence, cancer association, and mortality of DM and PM between 2003 and 2007.
Results A total of 803 DM and 500 PM cases were identified between 2003 and 2007. Mean age at diagnosis was 44·0 ± 18·3 years for DM and 49·2 ± 15·9 years for PM. The overall annual incidences of DM and PM were 7·1 (95% CI 6·6–7·6) and 4·4 (95% CI 4·0–4·8) cases per million population. The incidence of both DM and PM increased with age and reached a peak at age 50–59 years. One hundred and eleven (13·8%) patients with DM and 31 (6·2%) patients with PM had cancers. The diagnosis of most cancers was made after the diagnoses of DM (n = 71; 64·0%) and PM (n = 21; 67·7%). Overall, the standardized incidence ratios (SIR) for cancer were 5·36 (4·12–6·87) and 1·80 (1·10–2·79) among patients with DM and PM; however, during the first year, SIRs for cancer were 24·55 (95% CI 18·62–31·79) and 9·17 (95% CI 14·82–15·93) in patients with DM and PM, respectively. The most common types of cancer were nasopharyngeal cancer for men and breast cancer for women. Patients with DM and PM had standardized mortality ratios of 7·68 (6·41–9·01) and 5·29 (4·28–6·48).
Conclusion This study reports robust estimates of important aspects of the epidemiology of both DM and PM in Taiwan. This highlights the rarity of these diseases, and their associated cancer risks and increased mortality.
Individuals with mild cognitive impairment (MCI) are at high risk for developing dementia. Physical exercise is a promising intervention for cognitive decline. Systematic reviews regarding the ...effects of physical exercise on cognitive and psychological outcomes among MCI patients are limited, and a systematic review exploring the effects of exercise modalities on the results has not been conducted. This study evaluated the effects of physical exercise on cognitive and psychological outcomes for MCI patients and attempted to identify which specific modality of exercise is more effective.
Systematic review and meta-analysis.
A systematic search of Medline, CINAHL, EMBASE, PsycINFO, SPORTDiscus, and the China National Knowledge Infrastructure was performed.
Two reviewers independently assessed the study quality using the Effective Public Health Practice Project Quality Assessment Tool. Meta-analysis was conducted when data were available, with further subgroup analyses for exercise types. A series of sensitivity analyses were conducted to explore the influence of study quality and control types on the primary outcome. A narrative analysis was performed when statistical synthesis was inappropriate.
Eleven studies met the inclusion criteria. The exercise interventions can be classified into three types: (a) aerobic exercise, (b) resistance exercise, and (c) multi-modal exercise. Results showed that physical exercise had beneficial effects for global cognition standard mean difference (SMD) = 0.30, 95% confidence interval (CI): 0.10–0.49, p = 0.002. Further subgroup analysis demonstrated that aerobic exercise programmes are consistently associated with medium effect size (SMD: 0.54–0.58). However, the effects of physical exercise on domain-specific cognitive function and psychological outcomes in MCI patients remain inconclusive. Results of sensitivity analysis indicated that types of control exert influence on the outcomes.
Physical exercise, aerobic exercise in particular, benefits global cognition in MCI patients. The evidence of physical exercise on domain-specific cognitive function and psychological outcomes remains unclear, more trials with rigorous study design are necessary to provide the evidence.
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