Direction dependent free energy singularity of the asymmetric six-vertex model

The transition from the ordered commensurate phase to the incommensurate gaussian phase of the antiferroelectric asymmetric six-vertex model is investigated by keeping the temperature constant below the roughening point and varying the external fields $(h,v)$. In the $(h,v)$ plane, the phase boundary is approached along straight lines $\delta v=k \delta h$, where $(\delta h,\delta v)$ measures the displacement from the phase boundary. It is found that the free energy singularity displays the exponent 3/2 typical of the Pokrovski-Talapov transition $\delta f \sim const (\delta h)^{3/2}$ for any direction other than the tangential one. In the latter case $\delta f$ shows a discontinuity in the third derivative.Comment: 18 pages, Latex, 1 figure, minor corrections and two references change

Fateev-Zamolodchikov spin chain: excitation spectrum, completeness and thermodynamics

The sector of zero $Z_{N}$-charge is studied for the ferromagnetic (FM) and antiferromagnetic (AFM) version of the $Z_{N}\times Z_{2}$ invariant Fateev-Zamolodchikov quantum spin chain. We conjecture that the relevant Bethe ansatz equations should admit, beside the usual string-like solutions, exceptional multiplets, and a number of non-physical solutions. Once the physical ones are identified, we show how to get completeness and the gapless excitation spectrum. The central charge is computed from the specific heat and found to be $c=2\frac{N-1}{N+2}$ (FM) and $c=1$ (AFM).Comment: 30 pages, Late

Impact of body mass index on retention rates of anti-TNF-alfa drugs in daily practice for psoriasis

Psoriasis is a chronic inflammatory skin disease which often requires life-long treatment.Our objective was to assess the role of the body mass index (BMI) on the retention rates of anti-TNF-alfa therapies in patients with moderate to severe plaque psoriasis.Retrospective observational study of psoriasis patients included in local databases of three public Italian hospitals. All patients, who received anti-TNF-alfa treatment in referral centers, were included. Only patients with at least 1-year follow-up were considered eligible. The outcome was the conservation of the treatment at 1 and 2 years of follow-up.194 patients were enrolled. 307 treatment courses with a minimum follow-up of 12 months and 263 with a follow-up of 24 months were analyzed. The proportion of patients receiving the same treatment at months 12 and 24 was 67.43% and 42.21%, respectively. The proportion steadily decreased with increased values of BMI.The overall efficacy of TNF-alfa inhibitors diminishes with time. The BMI affects the long-term survival rate of anti-TNF-alfa in psoriatic patients. A high BMI can be considered a potential predictor of drug discontinuation

Mechanical ventilation and volutrauma: study in vivo of a healthy pig model

Mechanical ventilation is essential in intensive care units. However, it may itself induce lung injury. Current studies are based on rodents, using exceptionally large tidal volumes for very short periods, often after a "priming" pulmonary insult. Our study deepens a clinically relevant large animal model, closely resembling human physiology and the ventilator setting used in clinic settings. Our aim was to evaluate the pathophysiological mechanisms involved in alveolo/capillary barrier damage due to mechanical stress in healthy subjects. We randomly divided 18 pigs (sedated with medetomidine/tiletamine-zolazepam and anesthetised with thiopental sodium) into three groups (n=6): two were mechanically ventilated (tidal volume of 8 or 20 ml/kg), the third breathed spontaneously for 4 hours, then animals were sacrifi ced (thiopental overdose). We analyzed every 30' hemogasanalysis and the main circulatory and respiratory parameters. Matrix gelatinase expression was evaluated on bronchoalveolar lavage fl uid after surgery and before euthanasia. On autoptic samples we performed zymographic analysis of lung, kidney and liver tissues and histological examination of lung. Results evidenced that high V T evoked profound alterations of lung mechanics and structure, although low V T strategy was not devoid of side effects, too. Unexpectedly, also animals that were spontaneously breathing showed a worsening of the respiratory functions

Patient referral is influenced by dialysis centre structure in the Diamant Alpin Dialysis cohort study

Background. Late referral (LR) to the nephrologist of patients with progressing chronic kidney disease (CKD) has numerous deleterious effects and is observed in many countries. The contributing factors associated with LR are controversial and poorly defined. We hypothesized that these factors might be better identified by analysing patients starting dialysis in three distinct European countries within the same area. Method. The referral and progression of kidney failure patterns were analysed with demographic, clinical and biological data in 279 non-selected consecutive patients starting dialysis in eight centres of three adjacent regions in France, Italy and Switzerland. Results. Early referral (>6 months before the start of dialysis) was seen in 200 patients (71.6%), intermediate referral (1-6 months) in 42 (15.1%) and LR (<1 month) in 37 (13.3%). However inter-centre variations were between 2 and 19% for LR and 6-50% for combined late and intermediate referral. There were no differences at the national levels, but LR was more frequent in the large city centres than in the private or regional structures, with 31 out of 169 (18.3%), two out of 55 (5.4%) and four out of 55 (7.3%), respectively, of their patients (P<0.01). By multivariate analysis, it appears that, besides the presence of an active cancer and the CKD progression rate, the centre structure and the referring physician (primary care physicians and nephrologists are less responsible for LR than other medical specialists) play a significant role in the practice of LR. Conclusions. Within a dialysis cohort spread over adjacent regions of three countries, LR has the same global distribution pattern, indicating that different health and social security systems do not play a major role in inducing or preventing this practice. The contributing factors for LR that were identified are the type of the referring physician and the structure of the dialysis unit. Both factors are potential targets for an educational and collaborative approac