Weakly-Bound Three-Body Systems with No Bound Subsystems

We investigate the domain of coupling constants which achieve binding for a 3-body system, while none of the 2-body subsystems is bound. We derive some general properties of the shape of the domain, and rigorous upper bounds on its size, using a Hall--Post decomposition of the Hamiltonian. Numerical illustrations are provided in the case of a Yukawa potential, using a simple variational method.Comment: gzipped ps with 11 figures included. To appear in Phys. Rev.

Circulating B-vitamin biomarkers and B-vitamin supplement use in relation to quality of life in patients with colorectal cancer: results from the FOCUS consortium

Background: B vitamins have been associated with the risk and progression of colorectal cancer (CRC), given their central roles in nucleotide synthesis and methylation, yet their association with quality of life in established CRC is unclear.Objectives: To investigate whether quality of life 6 months postdiagnosis is associated with: 1) circulating concentrations of B vitamins and related biomarkers 6 months postdiagnosis; 2) changes in these concentrations between diagnosis and 6 months postdiagnosis; 3) B-vitamin supplement use 6 months postdiagnosis; and 4) changes in B-vitamin supplement use between diagnosis and 6 months postdiagnosis.Methods: We included 1676 newly diagnosed stage I-III CRC patients from 3 prospective European cohorts. Circulating concentrations of 9 biomarkers related to the B vitamins folate, riboflavin, vitamin B6, and cobalamin were measured at diagnosis and 6 months postdiagnosis. Information on dietary supplement use was collected at both time points. Health-related quality of life (global quality of life, functioning scales, and fatigue) was assessed by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire 6 months postdiagnosis. Confounder-adjusted linear regression analyses were performed, adjusted for multiple testing.Results: Higher pyridoxal 5'-phosphate (PLP) was cross-sectionally associated with better physical, role, and social functioning, as well as reduced fatigue, 6 months postdiagnosis. Associations were observed for a doubling in the hydroxykynurenine ratio [3-hydroxykynurenine: (kynurenic acid + xanthurenic acid + 3-hydroxyanthranilic acid + anthranilic acid); an inverse marker of vitamin B6] and both reduced global quality of life (beta = -3.62; 95% CI: -5.88, -1.36) and worse physical functioning (beta = -5.01; 95% CI: -7.09, -2.94). Dose-response relations were observed for PLP and quality of life. No associations were observed for changes in biomarker concentrations between diagnosis and 6 months. Participants who stopped using B-vitamin supplements after diagnosis reported higher fatigue than nonusers.Conclusions: Higher vitamin B6 status was associated with better quality of life, yet limited associations were observed for the use of B-vitamin supplements. Vitamin B6 needs further study to clarify its role in relation to quality of life

Stroke and apolipoprotein E (4 are independent risk factors for cognitive decline: a population-based study.

Background and Purpose —Stroke and apolipoprotein E ε4 (ApoE ε4) are individually important risk factors for cognitive decline, including Alzheimer disease. It has been suggested that ApoE ε4 multiplies the risk for cognitive decline following stroke. In a population-based sample, using well-defined sensitive cognitive measures, this study investigates whether cognitive decline following stroke is worse for patients who carry the ApoE ε4 allele. Methods —Subjects were participants in the Longitudinal Aging Study Amsterdam (LASA). The sample consisted of 1224 subjects, aged 62 to 85 years, who participated in the 3-year follow-up examination and for whom ApoE and stroke data were complete. We assessed cognitive decline using the Mini-Mental State Examination, the Auditory Verbal Learning Test (memory: immediate and delayed recall), and the Coding Task (information processing speed). The effects of stroke and ApoE ε4 on cognitive decline were evaluated with ANOVA and multiple logistic regression analysis, adjusted for age, sex, education, and baseline cognition. Results —A synergistic effect modification for stroke and ApoE ε4 on cognitive decline was not observed. Unexpectedly, instead, stroke patients carrying the ε4 allele demonstrated a nonsignificantly lowered risk for Mini-Mental State Examination decline (OR=0.3; 95% CI 0.1 to 1.1). ApoE ε4 was associated with declines in information processing speed (OR=1.5; 95% CI 1.1 to 2.1) and small declines for immediate and delayed recall. Conclusions —Stroke and ApoE ε4 may impair cognition through distinct nonsynergistic mechanisms. The slowing of information processing speed for ApoE ε4 carriers was more evident than impairment in memory. </jats:p

Oxidative stress, and iron and antioxidant status in elderly men: differences between the Mediterranean south (Crete) and northern Europe (Zutphen)

BACKGROUND: Oxidative stress may accelerate ageing and increase the risk of chronic diseases, such as coronary heart disease (CHD). We assessed differences in oxidative stress, and iron and antioxidant status between elderly men living in Mediterranean southern Europe (Crete, Greece) and northern Europe (Zutphen, The Netherlands). DESIGN: A cross-sectional study using data from two cohorts of the Seven Countries Study. METHODS: Non-fasting blood samples were drawn in 2000 from 105 men from Crete and 139 men from Zutphen, all aged 79 years or over. All assays were performed in the same laboratory. RESULTS: After multiple adjustments, serum levels of the markers of oxidative stress were lower in Cretan men than in men from Zutphen, as indicated by lower mean levels of hydroperoxides (33.2 versus 57.3 micromol/l; P=0.005) and gamma-glutamyltransferase (20.3 versus 26.1 U/l; P=0.003). The most pronounced difference in iron status was a twofold lower mean serum ferritin level in Cretan men (69.8 microg/l) compared with men from Zutphen (134.2 microg/l; P<0.0001). Men from Crete had consistently higher plasma levels of major plasma antioxidants than the Zutphen men, including a nearly fourfold higher mean level of lycopene (15.3 versus 4.1 microg/100 ml; P<0.0001). CONCLUSION: Elderly men from Crete had consistently lower levels of the indicators of oxidative stress and iron status and higher concentrations of major antioxidants than men from Zutphen. These differences may contribute to the lower rate of CHD and total mortality that has been observed in this cohort of Cretan men

Analysis of oxidative DNA damage after human dietary supplementation with linoleic acid

Analysis of oxidative DNA damage after human dietary supplementation with linoleic acid. de Kok TM, Zwingman I, Moonen EJ, Schilderman PA, Rhijnsburger E, Haenen GR, Kleinjans JC. Department of Health Risk Analysis and Toxicology, University Maastricht, PO Box 616, 6200 MD Maastricht, The Netherlands. [email protected] It has been hypothesized that oxygen radicals generated by peroxidation of dietary linoleic acid may induce genetic damage and thereby increase cancer risk. We examined the effect of dietary supplementation with linoleic acid on the levels of oxidative DNA damage in peripheral lymphocytes and on the blood plasma antioxidant potential. Thirty volunteers received during 6 weeks either a high dose of linoleic acid (15 g/day), an intermediate dose of linoleic acid (7.5 g/day) or an isocaloric supplement without linoleic acid (15 g palmitic acid/day). After the intervention, no significant increase in oxidative DNA damage, measured as relative amounts of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG) in DNA from peripheral lymphocytes, was observed in both high and intermediate linoleic acid-supplemented groups (increase of respectively 13 and 21%; P>0.05). Also, the differences between levels of oxidative DNA damage in the high or intermediate linoleic acid-supplemented group and the control group receiving palmitic acid (23% decrease) were not significant. Furthermore, no statistically significant differences were found between the total antioxidant capacities of blood plasma from the different experimental groups. Plasma levels of malondialdehyde, an important end-product of lipid peroxidation, were not increased after supplementation, nor were effects found on the plasma concentrations of retinol, alpha-tocopherol and beta-carotene. Despite the experimental design that excludes several forms of bias introduced in studies based on modulation of dietary composition, our results provide no indication of increased oxidative stress or genetic damage as a result of increased dietary intake of linoleic acid. Therefore, we see no scientific basis to reconsider the public health policy to stimulate the intake of polyunsaturated fatty acids aimed at the reduction of coronary heart diseases