Spin susceptibility of two-dimensional electrons in narrow AlAs quantum wells

We report measurements of the spin susceptibility in dilute two-dimensional electrons confined to a 45$\AA$ wide AlAs quantum well. The electrons in this well occupy an out-of-plane conduction-band valley, rendering a system similar to two-dimensional electrons in Si-MOSFETs but with only one valley occupied. We observe an enhancement of the spin susceptibility over the band value that increases as the density is decreased, following closely the prediction of quantum Monte Carlo calculations and continuing at finite values through the metal-insulator transition.Comment: 4+ pages, 4 figures. Dotted line added to Fig. 4(a) to clarify the QMC calculatio

Another Avenue for Anatomy of Income Comparisons : Evidence from Hypothetical Choice Experiments

September 2010, Revised December 2010, Secondly Revised November 2011, Thirdly Revised May 2012, Fourthly Revised March 2013

D-Penicillamine Metabolism in an In-Vivo Model of Inflamed Synovium

Oxidation to disulphides is the chief metabolic transformation of D-penicillamine (D-pen) in patients with rheumatoid arthritis. Oxidation also occurs in many biological fluids in-vitro. Reduction of oxygen species may accompany the oxidation of D-pen under appropriate conditions and may mediate the anti-rheumatic action of D-pen. The transformation of D-pen therefore was examined in an in-vivo model of inflamed synovium. Subcutaneous air-pouches of groups of rats were treated with saline, 10% serum or 10% zymosan activated serum (ZAS). The transformation of D-pen to low molecular weight (LMW) metabolites and protein conjugates within the pouch was then assessed. The concentrations of total protein were significantly higher in the serum and ZAS-treated groups than in the saline-treated group and the inflammatory cell counts were significantly higher in the ZAS-treated group than in either of the other groups, as expected. D-pen oxidised rapidly to LMW metabolites and smaller amounts of D-pen-protein conjugate (D-pen-protein) in the air pouches of all animals. The rates of oxidation to LMW metabolites were greater in the ZAS-treated animals than the saline-treated group (p less than 0.005). The concentrations of D-pen-protein conjugate were also greater for the serum-treated and ZAS-treated animals than for the saline controls (p less than 0.005 in each case) at all times. Oxidation of D-pen therefore occurs at this site of inflammation and is influenced by local conditions. This may be important to understanding the forms in which D-pen exists in inflamed synovial joints and the way it may exert its antirheumatic activity

Hand osteoarthritis is associated with limitations in paid and unpaid work participation and related societal costs: the HOSTAS cohort

Objectives Data on work participation impairment and related societal costs for patients with hand osteoarthritis (OA) are scarce. Therefore, we aimed to investigate the association of hand OA with work limitations and costs of productivity loss in paid and unpaid work. Methods We used data from the Hand Osteoarthritis in Secondary Care cohort, including patients with hand OA diagnosed by their treating rheumatologist. Using the validated Health and Labour Questionnaire, we assessed experienced unpaid and paid work restrictions, unpaid work replacement by others and inefficiency and absence during paid work related to hand OA over the last 2 weeks. Societal costs (euro) per hour of paid and unpaid work were estimated using Dutch salary data in 2019. Results 381 patients were included (mean age 61 years, 84% women, 26% high education level, 55% having any comorbidity). Replacement of unpaid work by others due to hand OA was necessary for 171 out of 381 patients (45%). Paid work was reported by 181/381 patients (47%), of whom 13/181 (7%) reported absenteeism, 28/181 (15%) unproductive hours at work and 120/181 (66%) paid work restrictions due to hand OA. Total estimated work-related societal costs per patient with hand OA (381 patients) were euro94 (95% CI 59 to 130) per 2 weeks (euro2452, 95% CI 1528 to 3377 per year). Conclusions Hand OA is associated with impairment in paid and unpaid work participation, which translates into substantial societal costs of lost productivity. These results highlight the importance of adequate hand OA treatment.Pathophysiology and treatment of rheumatic disease

Depressive mood and low social support are not associated with arthritis development in patients with seropositive arthralgia, although they predict increased musculoskeletal symptoms

Objective Studies on the role of psychosocial vulnerability in the development of arthritis must be performed early in the disease course to exclude the reverse explanation that arthritis leads to psychological symptoms. Therefore, the objective of this study was to investigate the longitudinal (5-year) association between depressive mood, daily stressors, avoidance coping and social support as predictors, and the development of arthritis and other clinical parameters as outcomes, in persons with seropositive arthralgia at risk of developing rheumatoid arthritis. Methods Five-year follow-up data of 231 patients from the Reade seropositive arthralgia cohort were used. Clinical and psychological data were collected using physical examinations and questionnaires. Mixed models and Cox regression analyses were used to assess the 5-year associations between depressive mood, daily stressors, avoidance coping or social support, and the development of arthritis or clinical parameters (tender joint count, Visual Analogue Scale (VAS) pain, VAS morning stiffness and erythrocyte sedimentation rate (ESR)). Results Higher scores for depressive mood and lower scores for social support were not associated with the development of arthritis nor with ESR. However, they were longitudinally associated with an increase in pain (p<0.001), morning stiffness (p<0.01) and tender joint count (p<0.001). No consistent associations were found between daily stressors, avoidance coping and the development of arthritis or other clinical parameters. Conclusion Although an effect on the development of arthritis could not be demonstrated, a strong longitudinal association was found between high depressive mood, low social support and clinical parameters. In persons with seropositive arthralgia, depressive symptoms and low social support may increase musculoskeletal symptoms