A fluid dynamics multidimensional model of biofilm growth: stability, influence of environment and sensitivity.

In this article, we study in detail the fluid dynamics system proposed in Clarelli et al. (2013, J. Math. Biol., 66, 1387-1408) to model the formation of cyanobacteria biofilms. After analysing the linear stability of the unique non-trivial equilibrium of the system, we introduce in the model the influence of light and temperature, which are two important factors for the development of a cyanobacteria biofilm. Since the values of the coefficients we use for our simulations are estimated through information found in the literature, some sensitivity and robustness analyses on these parameters are performed. All these elements enable us to control and to validate the model we have already derived and to present some numerical simulations in the 2D and the 3D cases.

A fluid dynamics model of the growth of phototrophic biofilms.

A system of nonlinear hyperbolic partial differential equations is derived using mixture theory to model the formation of biofilms. In contrast with most of the existing models, our equations have a finite speed of propagation, without using artificial free boundary conditions. Adapted numerical scheme will be described in detail and several simulations will be presented in one and more space dimensions in the particular case of cyanobacteria biofilms. Besides, the numerical scheme we present is able to deal in a natural and effective way with regions where one of the phases is vanishing.

Effects of rotational atherectomy with a reduced burr-to-artery ratio on coronary no-reflow.

AIM: The use of rotational atherectomy in addition to standard percutaneous coronary interventional procedures, although it improves coronary blood flow dynamics by improving vessel geometry, is often associated with distal embolization and the no-reflow phenomenon. We sought to evaluate the safety and effectiveness of a burr size/reference artery diameter (RAD) ratio <0.7 in rotational atherectomy in order to reduce the distal embolization and then to analyze the procedural and peri-procedural no-reflow phenomenon. METHODS: Between March 1999 and May 2003, 50 consecutive patients with a chronic stable angina lasting more than 3 months underwent rotablator atherectomy, adjunctive stent im-plantation (primary coronary stenting, PCS) or plain old balloon angioplasty (POBA) in case of de novo lesions or in stent restenosis, respectively. We analyzed the target vessel myocardial blush grade and the troponin I, creatine kinase and CK-MB values at 1.6 and every 8 h during the first day and then daily until discharge. RESULTS: Procedural success was achieved in all 50 patients (mean age 55+/-11 years; 45 males, 5 females). Quantitative angiography revealed, in the group treated with PCS, an increase in minimal lumen diameter (MLD) from 0.88+/-0.39 mm at baseline to 1.4+/-0.63 mm after rotablator (p<0.01) to 2.85+/-0.9 mm after stent implantation (p<0.01). On the other hand, for the group treated with POBA, the MLD changed from 1.8+/-0.32 mm at baseline to 2.2+/-0.54 mm after rotablator (p=0.6) to 3.28+/-0.91 mm after adjunctive balloon angioplasty (p<0.01). No statistically significant changes have been observed between myocardial blush grade and enzymes between baseline and after the procedure. CONCLUSION: Rotablator atherectomy with a reduced burr size/RAD ratio is a safe and effective interventional procedure without any peri-procedural no-reflow phenomenon.

[Systematic study of microbiological and parasitological quality of drinking water: the example of Cassino]. / Uno studio sistematico sulla qualità microbiologica e parassitologica delle acque potabili: l'esempio del cassinate.

In order to evaluate microbial and parasitological quality of water resources located in the area of Cassino, different typologies of water were monitored during the course of 2002. Analytical results showed that neither water sources nor chlorinated water were affected by microbial and parasitological contamination. Surface water can be used as drinking water after suitable treatment processes. The constant occurrence of parasitic protozoa in sewage shows their spreading in the environment; nevertheless their absence in groundwater and tap water suggests a good level of hygienic quality in water management.

[Utilization of permethrin-impregnated curtains by the inhabitants of a rural community in Burkina Faso]. / Utilisation de rideaux impregnés de perméthrine par les habitants d'une communauté rurale du Burkina Faso.

The degree of utilisation of permethrin-impregnated curtains was assessed in a rural community near Ouagadougou, Burkina Faso. Results showed that in the first half of the night, until 11-11.30 p.m., curtains were only partially used by the community. Indeed by this time around 50% of houses had doors well protected by curtains and, over 35% of the community, children and adults, were staying outside. A very marked pattern of this behavior was found, wrong utilisation of curtains being higher in the warm season and lower in the cold season. On the one hand, this situation decreased the potential action of curtains as a barrier to avoid mosquito-man contact and, on the other hand, facilitated the exposure of community to the risk of outdoor infection. These findings may explain the variable level of efficacy showed by curtains in the prevention of malaria morbidity, which seems to be higher in the period between January and February, the winter season in Burkina Faso. The possible application of impregnated curtains as a community-based vector control method is discussed.

[Usefulness of long-term monitoring of neonatal arterial pressure]. / Utilità del monitoraggio, a lungo termine, della pressione arteriosa neonatale.

30 newborns were studied, whose systolic arterial pressure has been controlled every 30 minutes 48 hours long, with oscillometric automatic technique. The resulting average of oscillation was 45.1 +/- 12.8 mmHg for systolic pressure and 36 +/- 11.4 mmHg for diastolic pressure. Wide pressure oscillations, you can find in some newborns, could be related with the development of a future pressure hypertension, and therefore a long term pressure monitoring would turn to a real useful test to single out future hypertensive subjects.

Isolation and molecular cloning of a fast-growing strain of human hepatitis A virus from its double-stranded replicative form.

A fast-growing strain of human hepatitis A virus was selected and characterized. The virus has the unusual property of developing a strong cytopathic effect in tissue culture in 7 to 10 days. Sequences of the viral genome were cloned into recombinant plasmids with the double-stranded replicative form as a template for the reverse transcription of cDNA. Restriction analysis and direct sequencing indicate that this strain is different from that described by Ticehurst et al. (Proc. Natl. Acad. Sci. USA 80:5885-5889, 1983) in the region that presumptively codes for the major capsid protein VP1, but both isolates have conserved large areas of homology in the untranslated 5'-terminal sequences of the genome.