Creation of a Pediatric Sedation Risk Assessment Scoring System: A Novel Method to Stratify Risk.

This study aimed to create a pediatric sedation scoring system independent of the American Society of Anesthesiology Physical Status (ASA-PS) classification that is predictive of adverse events, facilitates objective stratification, and resource allocation. Multivariable regression and machine learning algorithm analysis of 134,973 sedation encounters logged in to the Pediatric Sedation Research Consortium (PSRC) database between July 2007 and June 2011. Patient and procedure variables were correlated with adverse events with resultant ß -regression coefficients used to assign point values to each variable. Point values were then summed to create a risk assessment score. Validation of the model was performed with the 2011 to 2013 PSRC database followed by calculation of ROC curves and positive predictive values. Factors identified and resultant point values are as follows: 1 point: age ≤ 6 months, cardiac diagnosis, asthma, weight less than 5th percentile or greater than 95 th , and computed tomography (CT) scan; 2 points: magnetic resonance cholangiopancreatography (MRCP) and weight greater than 99th percentile; 4 points: magnetic resonance imaging (MRI); 5 points: trisomy 21 and esophagogastroduodenoscopy (EGD); 7 points: cough at the time of examination; and 18 points: bronchoscopy. Sum of patient and procedural values produced total risk assessment scores. Total risk assessment score of 5 had a sensitivity of 82.69% and a specificity of 26.22%, while risk assessment score of 11 had a sensitivity of 12.70% but a specificity of 95.29%. Inclusion of ASA-PS value did not improve model sensitivity or specificity and was thus excluded. Higher risk assessment scores predicted increased likelihood of adverse events during sedation. The score can be used to triage patients independent of ASA-PS with site-specific cut-off values used to determine appropriate sedation resource allocation.

Patient perspective on remission in rheumatoid arthritis: Validation of patient reported outcome instruments to measure absence of disease activity.

OBJECTIVE: Patients have identified pain, fatigue and independence as the most important domains that need to be improved to define remission in rheumatoid arthritis (RA). This study identified and validated instruments for these domains and evaluated their added value to the ACR/EULAR Boolean remission definition. METHODS: Patients with a 28-joint Disease Activity Score (DAS28) ≤3.2 or in self-perceived remission (declaring their disease activity 'as good as gone') from the Netherlands, Portugal, Australia, and Canada, were assessed at 0, 3 and 6 months for patient-reported outcomes and the WHO-ILAR RA core set. Instrument validity was evaluated cross-sectionally, longitudinally and for the ability to predict future good outcome in terms of physical functioning. Logistic regression quantified the added value to Boolean remission. RESULTS: Of 246 patients, 152 were also assessed at 3, and 142 at 6 months. Most instruments demonstrated construct validity and discriminative capacity. Pain and fatigue were best captured by a simple numerical rating scale (NRS). Measurement of independence proved more complex, but a newly developed independence NRS was preferred. NRS for pain, fatigue and independence, in addition to or instead of patient global assessment did not add enough information to justify modification of the current Boolean definition of remission in RA. CONCLUSION: Key elements of the patient perspective on remission in RA can be captured by NRS pain, fatigue, and independence. Although this study did not find conclusive evidence to improve the current definition of remission in RA, the information from these instruments adds value to the physician's assessment of remission and further bridges the gap between physician and patient.

The prevalence of gout and hyperuricaemia in Australia: An updated systematic review.

BACKGROUND: Gout continues to increase in prevalence in developed countries with Oceanic countries particularly affected. Both gout and hyperuricaemia are associated with the metabolic syndrome and its sequelae. Recently, the Australian Institute for Health and Welfare (AIHW) reported a prevalence rate of 0.8% which appeared incongruous with other published research. Thus, an updated systematic review was undertaken to review the literature on the prevalence of gout and hyperuricaemia in Australia from data published after 2011. METHODS: A comprehensive, systematic search was conducted in MEDLINE, Embase and Web of Science in addition to relevant websites to identify research reporting the prevalence of gout and/or hyperuricaemia in Australia from May 2011 until June 2020. Crude gout and hyperuricaemia prevalence data was obtained and presented alongside case ascertainment, time-period, age range and stratified by gender if available. RESULTS: 118 full text articles were screened. 12 articles were included for analysis of gout prevalence. 4 articles were identified for the hyperuricaemia analysis. Wide variation in prevalence figures exist largely due study design and sample age range. Studies using a case definition of self-reported diagnosis of gout reported prevalence rates between 4.5% and 6.8%. The remaining studies used either electronic coding data from general practitioners or wastewater estimation of allopurinol consumption and documented adult prevalence rates between 1.5% and 2.9%. Prevalence increases with age, male sex and over time in keeping with global data. Hyperuricaemia prevalence ranged between 10.5% and 16.6% in Caucasian or an Australian representative population. AIHW estimates applied a chronic condition status, defined as current and lasted or expected to last more than six months, to cases of gout in the Australian National Health Survey. This likely results in an under-estimation in reported Australian gout prevalence rates. CONCLUSIONS: Gout is highly prevalent in Australia compared to global comparisons and continues to increase over time. Hyperuricaemia prevalence is also high although contemporary data is limited.

Colchicine is not effective for reducing osteoarthritic hand pain compared to placebo: a randomised, placebo-controlled trial (COLAH).

BACKGROUND: Colchicine may offer relief in osteoarthritis. This has never been investigated for hand osteoarthritis. OBJECTIVES: To investigate the effect of 1 mg daily colchicine vs placebo on hand pain and function over 12 weeks in older adults with hand osteoarthritis. METHODS: Community-dwelling adults with diagnosed osteoarthritis of the hand aged 40-80 years were randomised to receive colchicine (0.5 mg twice daily) or matching placebo. Primary outcome measure was VAS hand pain score (0-100 mm). Secondary outcome measures included tender and swollen joint count, grip strength, C-reactive protein, and Michigan Hand Questionnaire total, function and pain scores. In an exploratory assessment, we compared synovial grade and power Doppler. All outcome measures were obtained at baseline and week 12. Stata v16 was used to perform constrained longitudinal data analysis models. RESULTS: 64 adults (54 females, 10 males) aged 48-79 years of age were enrolled. 59 participants completed the study (N = 28 colchicine, N = 31 placebo) (withdrawal rate 8%). Adverse reactions to the study medication occurred in nine patients. VAS score was not significantly different at baseline (61 ± 17 mm in the colchicine, 64 ± 17 mm in the placebo group). Between-group difference for VAS score at week 12 was 7.6 mm (95% CI -3.5-18.7, p-value 0.18). There were no significant differences between groups for any secondary outcomes at baseline or week 12. CONCLUSIONS: 1 mg colchicine daily for 12 weeks was not effective for reducing pain, tender and swollen joint count or increasing grip strength in symptomatic hand osteoarthritis. Our results do not support the use of colchicine in hand osteoarthritis.

Prevalence and associations of gout and hyperuricaemia: results from an Australian population-based study.

BACKGROUND: Despite gout and hyperuricaemia being major comorbid health issues worldwide, there is a knowledge gap regarding their impact in the Australian community. AIMS: To determine the prevalence and associations of self-reported medically diagnosed gout and hyperuricaemia in an Australian population-based cohort. METHODS: The North West Adelaide Health Study is a longitudinal cohort study consisting of three stages of data collection. Each stage comprised a self-complete questionnaire, clinic assessment and computer-assisted telephone interview. In Stage 3 (2008-2010), participants were asked if a doctor had ever diagnosed them with gout. Additional data included demographics, comorbidities, laboratory data and Short Form 36 (SF-36). Participants were defined as having gout if they had self-reported medically diagnosed gout or were taking any gout-specific medication (allopurinol, colchicine, probenecid). Hyperuricaemia was defined as a serum uric acid (SUA) level >0.42 mmol/L in men and >0.34 mmol/L in women. RESULTS: The overall prevalence of gout was 5.2%. Males were significantly more likely to have gout than females (8.5 vs 2.1%, P < 0.001). The overall prevalence of hyperuricaemia was 16.6%, with being male again identified as a significant risk factor (17.8 vs 15.4%, P < 0.01). Both gout and hyperuricaemia were associated with male sex, body mass index and renal disease after multivariable adjustment. There was no significant difference reported in quality of life (mean SF-36) scores in participants with gout compared to unaffected individuals. CONCLUSION: The prevalence of gout and hyperuricaemia is high in the South Australian population. This study emphasises the need for optimal diagnosis and management of gout in Australia.

Supplementation with omega-3 fish oil has no effect on bone mineral density in adults with knee osteoarthritis: a 2-year randomized controlled trial.

UNLABELLED: This study aimed to determine the effect of fish oil on bone mineral density (BMD). There were no differences in the 2-year BMD measures between high and low dose groups after adjusting for baseline BMD. This randomized controlled trial did not demonstrate any efficacy of omega-3 fatty acids on bone loss in adults. INTRODUCTION: The purpose of this study is to investigate whether supplementation with high dose omega-3 fish oil could have an impact on BMD. METHODS: In a multicentre, double-blind randomized controlled trial (RCT) (ACTRN 12607000415404), 202 Australian participants aged ≥40 with knee osteoarthritis (mean age, 61.0 ± 10.0 years; 49 % female) were randomized to receive either high dose (4.5 g eicosapentaenoic acid and docosahexaenoic acid daily) or low dose (0.45 g/day) omega-3 fish oil for 2 years. BMD was assessed at baseline and 2 years by dual energy X-ray absorptiometry. RESULTS: In subjects with baseline and 2-year assessments, mean standardized BMD at baseline for low or high dose group was 1198 ± 198 and 1157 ± 169 mg/cm(2), respectively, for the lumbar spine and was 1035 ± 165 and 1017 ± 174 mg/cm(2), respectively, for the femoral neck. There were no differences in the 2-year BMD measures between high and low dose groups after adjusting for baseline BMD in the complete case regression analyses (lumbar spine 3.7, 95 % confidence interval (CI) -7.9 to 15.3 mg/cm(2) and femoral neck -5.5, 95 % CI -14.9 to 3.9 mg/cm(2)). The findings did not change with additional adjustments of age, gender, study centre and uses of bone-related drugs during the study period as well as using the intention-to-treat analysis or limiting to older participants (≥55 years at the baseline) (all P ≥ 0.25). Mild adverse events such as headache and gastrointestinal intolerance were common but did not occur more frequently in either group. There were no serious adverse events related to the intervention. CONCLUSION: A 2-year supplementation with high-dose omega-3 fish oil did not alter bone loss among men and women with knee osteoarthritis.

Utility of temporal artery biopsy samples for genome-wide analysis of giant cell arteritis.

Giant Cell Arteritis (GCA) is the most common vasculitis affecting the elderly. Archived formalin-fixed paraffin-embedded (FFPE) temporal artery biopsy (TAB) specimens potentially represent a valuable resource for large-scale genetic analysis of this disease. FFPE TAB samples were obtained from 12 patients with GCA. Extracted TAB DNA was assessed by real time PCR before restoration using the Illumina HD FFPE Restore Kit. Paired FFPE-blood samples were genotyped on the Illumina OmniExpress FFPE microarray. The FFPE samples that passed stringent quality control measures had a mean genotyping success of >97%. When compared with their matching peripheral blood DNA, the mean discordant heterozygote and homozygote single nucleotide polymorphisms calls were 0.0028 and 0.0003, respectively, which is within the accepted tolerance of reproducibility. This work demonstrates that it is possible to successfully obtain high-quality microarray-based genotypes FFPE TAB samples and that this data is similar to that obtained from peripheral blood.

Epidemiology of biopsy-proven giant cell arteritis in South Australia.

BACKGROUND/AIM: To determine the epidemiology and clinical features of biopsy-proven giant cell arteritis (GCA) in South Australia (SA). METHODS: Patients with biopsy-proven GCA were identified from pathology reports of temporal artery biopsies at SA Pathology laboratories, from 1 January 1992, to 31 July 2011. Epidemiological data were collected through patient questionnaires and standardised case note reviews. Incidence was estimated using Australian Bureau of Statistics population data for SA. Seasonality was analysed by Cosinor analysis, and time-to- event analysis was performed for the duration of steroid use. RESULTS: There were 314 cases of biopsy-proven GCA (72% female). The mean age at diagnosis of GCA was 78 years (interquartile range 72-82). The estimated population incidence for people over 50 was 3.2 per 100,000 person years. The female : male incidence ratio was 2.3 (P < 0.001), and incidence increased with each age decade. There was evidence of seasonal variation (P = 0.015), with higher rates observed in the summer months. Clinical data were available for 163 patients (68% female, median age 78 years). The most common presenting clinical features were temporal headache (74%), visual disturbance (68.4%), jaw claudication (59.3%) and symptoms of polymyalgia rheumatica (56%). The median initial steroid dose was 60 mg, with median duration of steroid use 4.5 years. Corticosteroid side-effects were common, affecting 89%, with 34% reporting five or more. CONCLUSIONS: This is the first epidemiological study of Australian biopsy-proven GCA patients. Age at onset and gender associations were similar to other Western populations. There was a high burden of steroid use in these patients.

Decline in hand bone mineral density indicates increased risk of erosive change in early rheumatoid arthritis.

OBJECTIVE: Despite better disease suppression with combination disease-modifying antirheumatic drugs (DMARDs), some patients with rheumatoid arthritis (RA) have progressive erosive disease. The objective of this study was to determine whether hand bone mineral density (BMD) loss in the first 6 months of treatment indicates increased risk of erosions at 12 months. METHODS: Patients with DMARD-naive early RA receiving treat-to-target therapy were studied (n = 106). Hand BMD was measured at baseline and 6 months by dual x-ray absorptiometry. Hand and feet radiographs were performed at baseline and 12 months and scored using the van der Heijde modification of the Sharp method. A K-means clustering algorithm was used to divide patients into 2 groups: the BMD loss group or the no loss group, according to their absolute change in BMD from baseline to 6 months. Multiple regression analysis (hurdle model) was performed to determine the risk factors for both erosive disease and erosion scores. RESULTS: Hand BMD loss at 6 months was associated with erosion scores at 12 months (P = 0.021). In a multiple regression analysis, hand BMD loss (P = 0.046) and older age at onset (≥50 years; P = 0.014) were associated with erosive disease, whereas baseline erosion scores (P = 0.001) and anti-cyclic citrullinated peptide (P = 0.024) were correlated with erosion severity/progression. CONCLUSION: In RA patients receiving treat-to-target therapy, early hand BMD loss could identify patients who are at risk of developing erosive disease at 12 months, potentially allowing intensification of treatment to prevent erosive damage.

Shoulder pain in the community: an examination of associative factors using a longitudinal cohort study.

OBJECTIVE: To determine factors that are predictive of incident, recurrent, or resolved shoulder pain in a community-based sample from the general population. METHODS: This study used data from the North West Adelaide Health Study, a cohort study located in the northwestern suburbs of Adelaide, South Australia. Data were obtained between 2004 and 2006 and between 2008 and 2010, with time between measurements ranging from 2-6 years (median 4 years), using a computer-assisted telephone interview, a clinical assessment, and a self-completed questionnaire. Multivariate logistic regression was used to examine the factors associated with shoulder pain. RESULTS: Overall, 14.6% (95% confidence interval [95% CI] 12.7-16.7) of 2,337 eligible participants reported that they had developed (or had incident) shoulder pain between 2 time points of the cohort study, 8.8% (95% CI 7.5-10.3) reported recurrent shoulder pain, and 8.7% (95% CI 7.0-10.6) had resolved shoulder pain. Incident shoulder pain was significantly associated with physically heavier occupational activities and pain in other joints after adjustment for age, sex, and body mass index. Recurrent shoulder pain was also associated with pain in other joints, but also with depressive symptoms, smoking, and decreased shoulder range of movement. Resolved shoulder pain was associated with being female, other areas of pain, and decreased shoulder range of movement, but higher grip strength. CONCLUSION: Different factors were associated with incident, recurrent, or resolved shoulder pain in a longitudinal cohort study. Consideration of all of these factors may assist in the prevention and management of shoulder pain and the possible identification of those at risk of long-term shoulder problems.

Untreated hypertension: prevalence and patient factors and beliefs associated with under-treatment in a population sample.

Identifying barriers to hypertension management may facilitate cardiovascular risk reduction. Therefore, our objective, was to determine the prevalence of hypertension not managed with medication ('untreated') in a representative adult sample and identify patient factors/beliefs, and aspects of the patient-general practitioner (GP) relationship associated with untreated hypertension. The North West Adelaide Health Study, a biomedical cohort study over three stages from 2000-2009, assesses hypertension (systolic > or =140 mm Hg and/or > or =90 mm Hg or current treatment with anti-hypertensive medication), chronic disease and associated risk factors and health-care experiences, including risk perception, decision-making preferences, GP/primary care provider affiliation and satisfaction with care (n=2425). The prevalence of hypertension was 32.1% (n=781) comprised of treated (19.0%, n=462) and untreated (13.1%, n=319) hypertension. Thus, 40.8% of hypertension was untreated. Among hypertensive subjects, non-treatment was significantly associated with male sex, age <45 years, workforce participation, infrequent GP visits, dissatisfaction with recent medical care, high total cholesterol, moderate-level physical activity and lower body weights. Compared with participants without hypertension (and no treatment), untreated subjects demonstrated significant (15%) 10-year Framingham general cardiovascular risk (odds ratio=6.44, 95% confidence interval=4.52-9.17). Novel screening strategies and public health messages to address beliefs and perceptions of both patients and the health system are required to identify untreated, at-risk hypertensive individuals.

Osteoporosis in the community: Sensitivity of self-reported estimates and medication use of those diagnosed with the condition.

OBJECTIVES: To assess the sensitivity and specificity of self-reported osteoporosis compared with dual energy X-ray absorptiometry (DXA) defined osteoporosis, and to describe medication use among participants with the condition. METHODS: Data were obtained from a population-based longitudinal study and assessed for the prevalence of osteoporosis, falls, fractures and medication use. DXA scans were also undertaken. RESULTS: Overall 3.8% (95% confidence interval (CI) 3.2 to 4.5) of respondents and 8.8% (95% CI 7.5 to 10.3) of those aged ≥ 50 years reported that they had been diagnosed with osteoporosis by a doctor. The sensitivity (those self-reporting osteoporosis and having low bone mineral density (BMD) on DXA) was low (22.7%), although the specificity was high (94.4%). Only 16.1% of those aged ≥ 50 years and with DXA-defined osteoporosis were taking bisphosphonates. CONCLUSIONS: The sensitivity of self-reporting to identify osteoporosis is low. Anti-osteoporotic medications are an important part of osteoporosis treatment but opportunities to use appropriate medications were missed and inappropriate medications were used.

Prevalence and associations of hand pain in the community: results from a population-based study.

OBJECTIVES: To assess the prevalence and associations of hand symptoms in a community setting. METHODS: The North West Adelaide Health Study (NWAHS) is a longitudinal cohort study of people aged ≥ 18 years. Analysis was performed in participants who completed a telephone interview, a quality of life questionnaire [the 36-item short-form health survey, (SF-36)], and the Australian/Canadian (AUSCAN) Osteoarthritis (OA) Hand Index, and underwent grip strength measurement. RESULTS: Overall, 477 (13.7%) reported hand pain, aching, or stiffness. Of these, 169 (35.8%) had been diagnosed with hand arthritis. Women were more likely to have hand symptoms than men, as were those aged ≥ 50 years (p < 0.001). Hand symptoms were associated with lower quality of life scores (p < 0.05). Participants with hand arthritis had more severe pain, stiffness, and poorer physical functioning as reflected by higher AUSCAN scores. Grip strength was reduced in those with hand symptoms and hand arthritis (p < 0.05) and inversely associated with mean AUSCAN subscores and SF-36 physical functioning scores (p < 0.001). CONCLUSIONS: Hand symptoms were present in 14% of the population and were more common in women and those aged ≥ 50 years. Hand symptoms were associated with reduced grip strength and reduced quality of life. Hand arthritis was associated with higher AUSCAN scores. Hand symptoms and hand arthritis have a significant impact on physical functioning and quality of life.

Does leisure time physical activity protect against shoulder pain at work?

BACKGROUND: Shoulder pain is a common problem that can impact on work. Leisure time physical activity (LTPA) has the potential to reduce the impact of shoulder pain through its physiological, psychological and social benefits. AIMS: To determine whether LTPA reduces the prevalence of shoulder pain in a working population. METHODS: Participants were selected from a longitudinal population-based cohort study, the North West Adelaide Health Study. Information was gathered by questionnaire on LTPA, smoking, depression and socio-economic factors. Body mass index was measured in a clinic setting. Occupational physical activity (OPA) estimated by job title and shoulder pain was measured using the Shoulder Pain and Disability Index. Workers with and without shoulder pain were compared using logistic regression analysis. RESULTS: Of the 1502 working participants, 16% reported having current shoulder pain. Shoulder pain was associated with older age (OR 1.98, 95% CI: 1.31-2.99) (age >50 years), smoking (OR 1.44, CI: 1.02-2.04), secondary-level educational attainment (OR 1.68, 95% CI: 1.07-2.65), high body mass index (BMI) (OR 1.54, 95% CI: 1.14-2.08) and depression (OR 2.42, 95% CI: 1.60-3.64). There was no effect of LTPA on shoulder pain. CONCLUSIONS: In this community-based cohort, there was no statistically significant association seen between LTPA, OPA and shoulder pain. There was, however, an association between smoking, BMI, secondary-level education, depression and shoulder pain. These modifiable factors may be better targets for preventive efforts than LTPA to reduce the risk of shoulder pain.

Dystocia in a Rothschild giraffe leading to a caesarean section.

A 9-year-old female Rothschild giraffe (Giraffa camelopardalis rothschildi), weighing approximately 900 kg, at Longleat Safari Park, Wiltshire, UK was presented with dystocia in September 2005. This paper details the surgical and anaesthetic procedures carried out performing a caesarean section to remove a dead male calf and the successful recovery of the giraffe.

Risk of cancer in patients with scleroderma: a population based cohort study.

BACKGROUND: Previous studies have suggested an increased risk of cancer among patients with scleroderma. OBJECTIVE: To study a population based cohort of patients with scleroderma in South Australia. METHODS: Subjects with scleroderma were identified from the South Australian Scleroderma Registry established in 1993. All subjects on the scleroderma registry were linked to the South Australian Cancer Registry to identify all cases of cancer until 31 December 2000. Standardised incidence ratios (SIRs) for cancer for subjects with scleroderma were determined using the age- and sex-specific rates for South Australia. RESULTS: In 441 patients with scleroderma, 90 cases of cancer were identified, 47 of which developed after inclusion on the scleroderma registry. The SIRs for all cancers among these patients were significantly increased (SIR=1.99; 95% confidence interval (95% CI) 1.46 to 2.65) compared with the cancer incidence rates for South Australia. The SIRs for lung cancer (SIR=5.9; 95% CI 3.05 to 10.31) were also significantly increased. The SIRs for all cancers among the subgroups with diffuse scleroderma (SIR=2.73; 95% CI 1.31 to 5.02) and limited scleroderma (SIR=1.85; 95% CI 1.23 to 2.68) were significantly increased. CONCLUSIONS: This population based cohort study provides evidence that scleroderma is associated with cancer, and in particular, lung cancer. In addition, both diffuse and limited forms of scleroderma are associated with a similarly increased risk of cancer.

Formation, isomerization, and derivatization of Keggin tungstoaluminates.

Trends in the stability of alpha- and beta-Keggin heteropolytungstates of the second-row main-group heteroatoms Al(III), Si(IV), and P(V) are elaborated by data that establish the roles of kinetic and thermodynamic control in the formation and isomerization of Keggin tungstoaluminates. Slow, room-temperature co-condensation of Al(III) and W(VI) (2:11 molar ratio) in water gives a pH 7 solution containing beta(1) and beta(2) isomers of [Al(AlOH(2))W(11)O(39)](6)(-) (beta(1)- and beta(2)-1). Partial equilibration of this kinetic product mixture by gentle heating (2 h at 100 degrees C) or, alternatively, co-condensation of Al(III) and W(VI) for 2.5 h at 100 degrees C both give mixtures of beta(2)-, beta(3)-, and alpha-1. Full equilibration, by prolonged heating (25 days at 100 degrees C), gives an isomerically pure solution of alpha-1, thus demonstrating that isomerization occurs in the direction beta(1) --> beta(2) --> beta(3) --> alpha. Furthermore, kinetically controlled conversions of 1 to H(5)[AlW(12)O(40)] (2)-achieved by heating pH 0-0.2 solutions of 1 for 5 days at 100 degrees C-occur with retention of isomeric integrity, such that alpha-1 is converted to alpha-2 (92%; 8% beta), while mixtures of beta(2)- and beta(3)-1 are converted to beta-2 (87%; 13% alpha). These data, when combined with previously reported observations (equilibria between alpha- and beta-2, kinetically controlled hydrolyses of alpha-2 to alpha-[AlW(11)O(39)](9)(-) (alpha-3) and of beta-2 to beta(2)-3, and equilibria between beta(3)- and alpha-3), provide a comprehensive picture regarding the roles of kinetic and thermodynamic control. Finally, a general method for preparation of the isomerically pure derivatives alpha-K(9)(-)(n)()[AlM(n)()(+)W(11)O(39)] (4), M(n)()(+) = Al(III), [V(IV)O](2+), [V(V)O](3+), Mn(II), Mn(III), Mn(IV), Co(II), and Co(III), is provided. The presence of Mn(IV) is confirmed by cyclic voltammetry, pK(a) values of the aquo ligands on 4 are determined by pH titration, and the isomeric structure of these derivatives is established by (27)Al, (51)V, and (183)W NMR and IR spectroscopies and X-ray crystallography.

Equilibrating metal-oxide cluster ensembles for oxidation reactions using oxygen in water.

Although many enzymes can readily and selectively use oxygen in water-the most familiar and attractive of all oxidants and solvents, respectively-the design of synthetic catalysts for selective water-based oxidation processes utilizing molecular oxygen remains a daunting task. Particularly problematic is the fact that oxidation of substrates by O2 involves radical chemistry, which is intrinsically non-selective and difficult to control. In addition, metallo-organic catalysts are inherently susceptible to degradation by oxygen-based radicals, while their transition-metal-ion active sites often react with water to give insoluble, and thus inactive, oxides or hydroxides. Furthermore, pH control is often required to avoid acid or base degradation of organic substrates or products. Unlike metallo-organic catalysts, polyoxometalate anions are oxidatively stable and are reversible oxidants for use with O2 (refs 8,9,10). Here we show how thermodynamically controlled self-assembly of an equilibrated ensemble of polyoxometalates, with the heteropolytungstate anion [AIVVW11O40]6- as its main component, imparts both stability in water and internal pH-management. Designed to operate at near-neutral pH, this system facilitates a two-step O2-based process for the selective delignification of wood (lignocellulose) fibres. By directly monitoring the central Al atom, we show that equilibration reactions typical of polyoxometalate anions keep the pH of the system near 7 during both process steps.

Asymmetric sandwich-type polyoxoanions. Synthesis, characterization, and x-ray crystal structures of diferric complexes [TM(II)Fe(III)(2)(P(2)W(15)O(56))(P(2)TM(II)(2)W(13)O(52))](16-), TM = Cu or Co.

Reaction of the diferric sandwich-type polyoxometalate (NaOH(2))(2)Fe(III)(2)(P(2)W(15)O(56))(2)(16-)(1) with excess aqueous Cu(II) or Co(II) yields a new type of d-electron-metal substituted polyoxometalate, [TM(II)Fe(III)(2)(P(2)W(15)O(56)) (P(2)TM(II)(2)W(13)O(52))](16-), TM = Cu (2), Co (3), respectively. The structure of the sodium salt of 2 (Na2), determined by single-crystal X-ray diffraction analysis (a = 13.4413(9) A, b = 21.2590(15) A, c = 25.5207(18) A, alpha = 80.475(2) degrees, beta = 85.555(2) degrees, gamma = 89.563(2) degrees, triclinic, P(-)1, R1 = 5.42%, based on 43097 independent reflections), consists of a defect Fe(2)Cu central unit sandwiched between two different trivacant Wells-Dawson-type units, P(2)W(15) and P(2)Cu(2)W(13), where the latter unit has two octahedral Cu(II) ions substituted for two adjacent belt W(VI) atoms. The CuO(5)OH(2) octahedron in the central unit shows pronounced Jahn-Teller distortion. A low-resolution X-ray structure of Na3 is included in the Supporting Information. UV-visible, infrared, (31)P NMR, cyclic voltammetric, and elemental analysis data are all consistent with the structure determined from the X-ray analysis. Cyclic voltammograms of 2 and 3 exhibit multiple electron-transfer processes under ambient conditions, and copper or cobalt incorporation into the framework of 1 results in a substantial pertubation of the electrochemical properties of the polyoxotungstate framework. The tetra-n-butylammonium salts of 2 and 3 (readily prepared by metathesis) are stable and effective catalysts for the oxidation of some alkenes with high yields based on H(2)O(2).