Stochastic and deterministic models for nucleation and growth in non-isothermal and/or non-isobaric powder transformations

The calculation of fractional conversion can be very difficult in certain cases of nucleation and growth transformations (Mampel assumptions): it has only been developed for a few shapes of grains (spheres, cylinders) and only in isobaric and isothermal conditions. Here, a stochastic model which is intrinsically independent on geometry and which stands for non-isobaric and/or non-isothermal reactions is presented. The numerical evaluation of this model can be carried out in two different ways. First a slow Monte Carlo approach which is valid for all kinds of shapes and external conditions is presented, then, a faster, more classical approach is given which allows changing external conditions but only for well-known shapes.     

Urokinase-type plasminogen activator receptor in gastric cancer: tissue expression and prognostic role

The urokinase-type plasminogen activator (UPA) and its inhibitor PAI-1 are thought to play an important part in gastric cancer (GC) invasion and metastasis. Little is known about the behavior and prognostic impact of the receptor for UPA (UPAR). The aims of the present study were: (1) to measure UPAR, UPA and PAI-1 levels in GC and in non-malignant tissue distant from the tumor (NORM); (2) to evaluate their relationship with histomorphological parameters; and (3) to determine their prognostic value. UPAR, UPA and PAI-1 levels were determined by ELISA in GC and NORM samples from 20 patients with GC undergoing surgery. The GC was also examined in terms of the presence (n = 10) or absence (n = 10) of metastasis, differentiation (five differentiated, 15 undifferentiated) and histotype. Survival was analysed using life table analysis. UPAR, UPA and PAI-1 were significantly higher in GC vs NORM, in the presence of metastasis (UPAR, UPA) and in undifferentiated GC (UPAR, PAI-1). UPAR significantly correlated with UPA and PAI-1. Low levels of UPAR (P = 0.04), UPA (P = 0.007) and PAI-1 (P = 0.02) were associated with a better survival. Our results demonstrate a sharp increase in UPAR in GC and suggest a prognostic role for it. The concomitant activation of UPAR, UPA and PAI-1 in GC confirm the important role of the plasminogen activator system in the process of invasion and metastasis.     

Activity-rest stimulation of latissimus dorsi for cardiomyoplasty: 1-year results in sheep

BACKGROUND: In dynamic cardiomyoplasty electro-stimulation achieves full transformation of the latissimus dorsi (LD); therefore, its slowness limits the systolic support. Daily activity-rest could maintain partial transformation of the LD. METHODS: Sheep LD were burst-stimulated either 10 or 24 hours/day. Before and 2, 4, 6, and 12 months after stimulation, LD power output, fatigue resistance, and tetanic fusion frequency were assessed. Latissimus dorsi were biopsied at 6 months, and sheep sacrificed at 12 months. RESULTS: After 1 year of 10 hours/day stimulation LD was substantially conserved and contained large amounts of fast type myosin. From 2 months to 1 year of stimulation the power per muscle of the daily rested LD was greater than that of the left ventricle, being three to four times higher than in the 24-hour/day stimulation. CONCLUSIONS: If extended to humans, these results could be the rationale for the need of a cardiomyostimulator, whose discontinuous activity could offer to patients the long-standing advantage of a faster and powerful muscle contraction.     

Enhanced Hydrogen Production by Photoreforming of Renewable Oxygenates Through Nanostructured Fe2O3 Polymorphs

Sunlight‐driven hydrogen production via photoreforming of aqueous solutions containing renewable compounds is an attractive option for sustainable energy generation with reduced carbon footprint. Nevertheless, the absence of photocatalysts combining high efficiency and stability upon solar light activation has up to date strongly hindered the development of this technology. Herein, two scarcely investigated iron(III) oxide polymorphs, β‐ and ε‐Fe₂O₃, possessing a remarkable activity in sunlight‐activated H₂ generation from aqueous solutions of renewable oxygenates (i.e., ethanol, glycerol, glucose) are reported. For β‐Fe₂O₃ and ε‐Fe₂O₃, H₂ production rates up to 225 and 125 mmol h^?1 m^?2 are obtained, with significantly superior performances with respect to the commonly investigated α‐Fe₂O₃.     

Lithiasic, congenital, choledochal dilatation: problems of diagnosis and therapy

We report a case of a 30-year old female with congenital lithiasic choledochal dilatation which was not diagnosed at the ultrasonographic examination. Congenital biliary dilatation abnormalities are rare and may clinically present with episodic biliary colics or more rarely with recurrent pancreatis. Ultrasound, CT-scanning and ERCP usually make these anatomic alterations evident but in some cases there may be some doubt despite the vast range of radiological techniques available (PTC, Tc99m-Isida scinti-scan). The best results from a diagnostic point of view are obtained from the ERCP that may in fact visualize an anomalous pancreatico-biliary junction, rule out carcinoma, accurately define the cyst dimensions or show the intrahepatic ductal radicals. Furthermore, the extraction of intracystic stones or the treatment of choledochocele through a papillostomy may be performed. However the ERCP may cause traumatic pancreatitis, above all in youngster as was verified in our patient. During surgical exploration, the definitive diagnosis can be achieved via intraoperative cholangiography. We emphasize that in patients with congenital choledochal dilatation, the dilated choledochus should be excised even in young children to avoid the risk of malignancy which may occur also following cyso-duodeno- or cystojejunostomy treatment. In our patient an hepatiocojejunostomy on a Roux-en-Y limb was performed. This single case has been oresented along with a review of the literature to recall such anomalies in differential diagnosis of biliary colics and to stress that the choice treatment is surgical resection.     

Stability of helium and hydrogen films

We use the variational theorem to evaluate the domain of parameter space such thatsome film exists on a given surface. This is accomplished by determining the binding energy variationally for a monolayer film at T=0. The He results are for the most part consistent with those of Cheng, et al., for the domain of wetting films. New results for H₂ are compared with calculated parameters of noble gas adsorption potentials.