Spin Stiffness of Mesoscopic Quantum Antiferromagnets

We study the spin stiffness of a one-dimensional quantum antiferromagnet in the whole range of system sizes $L$ and temperatures $T$. We show that for integer and half-odd integer spin case the stiffness differs fundamentally in its $L$ and $T$ dependence, and that in the latter case the stiffness exhibits a striking dependence on the parity of the number of sites. Integer spin chains are treated in terms of the non-linear sigma model, while half-odd integer spin chains are discussed in a renormalization group approach leading to a Luttinger liquid with Aharonov-Bohm type boundary conditions.Comment: 12 pages, LaTe

Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed $Q^2$-dependence is smooth. The measured ratio of H$(e,e'p)\gamma$ to H$(e,e'p)\pi^0$ cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest $W$ (1.8-1.9 GeV) show a striking $Q^2$- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.

Genotoxic effect induced by hydrogen peroxide in human hepatoma cells using comet assay

Background: Hydrogen peroxide is a common reactive oxygen intermediate generated by variousforms of oxidative stress. Aims: The aim of this study was to investigate the DNA damage capacity ofH2O2 in HepG2 cells. Methods: Cells were treated with H2O2 at concentrations of 25 μM or 50 μM for5 min, 30 min, 40 min, 1 h or 24 h in parallel. The extent of DNA damage was assessed by the cometassay. Results: Compared to the control, DNA damage by 25 μM and 50 μM H2O2 increasedsignificantly with increasing incubation time up to 1 h, but it was not increased at 24 h. Conclusions:Our Findings confirm that H2O2 is a typical DNA damage inducing agent and thus is a good modelsystem to study the effects of oxidative stress. DNA damage in HepG2 cells increased significantlywith H2O2 concentration and time of incubation but later decreased likely due to DNA repairmechanisms and antioxidant enzyme

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200

Continuous glucose monitoring reduces both hypoglycaemia and HbA1c in hypoglycaemia-prone type 1 diabetic patients treated with a portable pump.

AIM: This study aimed to assess the effectiveness of continuous glucose monitoring (CGM) for glucose control in type 1 diabetic patients treated by continuous subcutaneous insulin infusion (CSII) and presenting with frequent hypoglycaemic episodes. METHODS: Thirteen patients with type 1 diabetes (diabetes duration: 25+/-15 years; CSII duration: 5.5+/-7.0 years), with more than six recorded capillary blood glucose (CBG) values <60 mg/dL, according to their metres for the past 14 days, were offered the permanent use of a CGM device (Guardian RT((R)), Medtronic) plus ongoing self-monitoring of blood glucose (SMBG) for 12 weeks, followed by a 12-week crossover period of SMBG only, or vice versa. Glucose control, determined by recorded 14-day CBG values <60 mg/dL and HbA(1c) levels, and quality of life according to the Diabetes Quality of Life (DQOL) questionnaire, were assessed at baseline, and after 12- and 24-week follow-ups. RESULTS: Four patients withdrew from the study during the first period (of whom three were using CGM). In the nine study completers, the number of low CBG values decreased significantly from 13.9+/-9.2 to 7.6+/-6.8 (P=0.011) when patients used CGM, in either the initial or final trial period, while a decrease in HbA(1c) from 8.3+/-0.7 to 7.7+/-0.6% (P=0.049) was also observed, in contrast to the absence of any significant differences during the SMBG-only period. DQOL scores were also essentially unaffected. CONCLUSION: This pilot observational study supports the hypothesis that CGM use can significantly improve overall glucose control while reducing hypoglycaemic episodes in hypoglycaemia-prone type 1 diabetic patients treated by CSII.L’apport d’une mesure continue du glucose réduit le taux d’HbA1c et la fréquence des hypoglycémies chez des patients diabétiques de type 1 traités par pompe portable à insuline et à risque hypoglycémique. Objectif. – Étudier l’efficacité d’un système de mesure continue du glucose sur le contrôle glycémique de patients diabétiques de type 1 traités par pompe portable à insuline et présentant des hypoglycémies fréquentes. Méthodes. – Treize patients diabétiques de type 1 (durée du diabète : 25±15 années ; durée du traitement par pompe : 5,5±7,0 années), présentant plus de six glycémies capillaires inférieures à 60 mg/dl enregistrées dans leur lecteur à mémoire durant les 14 derniers jours, ont participé à une étude observationnelle. Cette dernière comprenait deux périodes de 12 semaines en ordre croisé, avec soit le recours complémentaire à un système de monitoring du glucose (GuardianRT®, Medtronic), soit seulement la poursuite de l’autosurveillance glycémique habituelle. Le contrôle glycémique, évalué sur la base du nombre de glycémies capillaires inférieures à 60 mg/dl au cours des 14 derniers jours et du taux d’HbA1c, et la qualité de vie ont été analysés à l’inclusion, après 12 semaines et après 24 semaines. Résultats. – Quatre patients se sont retirés de l’essai durant la première période (dont trois alors qu’ils étaient sous Guardian RT®). Chez les neuf patients ayant achevé l’étude, le nombre de valeurs glycémiques basses a diminué de 13,9±9,2 à 7,6±6,8 (p = 0,011) lorsque les patients utilisaient le Guardian RT®, que ce soit en période 1 ou en période 2, tout en obtenant une réduction du taux d’HbA1c de 8,3±0,7 à 7,7±0,6% (p = 0,049), alors qu’il n’y avait pas de différences significatives durant la période sous simple autosurveillance glycémique habituelle. La qualité de vie n’a pas paru affectée

FRUITGRADING: Development of a fruit sorting technology based on internal quality parameters

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