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A Buonocore

Publications and source records attributed to A Buonocore.

8 recordsLinked to original sources
PubMed2005

On Myosin II dynamics in the presence of external loads.

We address the controversial hot question concerning the validity of the loose coupling versus the lever-arm theories in the actomyosin dynamics by re-interpreting and extending the phenomenological washboard potential model proposed by some of us in a previous paper. In this new model a Brownian motion harnessing thermal energy is assumed to co-exist with the deterministic swing of the lever-arm, to yield an excellent fit of the set of data obtained by some of us on the sliding of Myosin II heads on immobilized actin filaments under various load conditions. Our theoretical arguments are complemented by accurate numerical simulations, and the robustness of the model is tested via different choices of parameters and potential profiles.

Actins↗
PubMed2003

Exploiting thermal noise for an efficient actomyosin sliding mechanism.

With reference to the experimental observations by Yanagida and his co-workers concerning actomyosin interaction during muscle contraction processes, we propose a phenomenological model for the sliding of the myosin head on the actin filament, in which the myosin head is viewed as an active Brownian particle in a periodic, elastic-type potential subject to tilting. The sample paths thus obtained are qualitatively alike to those experimentally recorded. Furthermore, our model is proved to be susceptible of a consistent parameters regulation yielding step frequencies, mean step dwell time and dwell time distribution in excellent agreement with the experimental evidence.

Actomyosin↗
PubMed2003

A chemically driven fluctuating ratchet model for actomyosin interaction.

With reference to the experimental observations by Yanagida and his co-workers on actomyosin interaction, a Brownian motor of fluctuating ratchet kind is designed with the aim to describe the interaction between a Myosin II head and a neighboring actin filament. Our motor combines the dynamics of the myosin head with a chemical external system related to the ATP cycle, whose role is to provide the energy supply necessary to bias the motion. Analytical expressions for the duration of the ATP cycle, for the Gibbs free energy and for the net displacement of the myosin head are obtained. Finally, by exploiting a method due to Sekimoto [J. Phys. Soc. Jpn. 66 (1997) 1234], a formula is worked out for the amount of energy consumed during the ATP cycle.

Actins↗
PubMed2002

New microencapsulated sunscreens: technology and comparative evaluation.

The aim of this work is to obtain new technologically improved microencapsulated sunscreens characterised by UV-radiation stability, good substantivity, low toxicity, a better tolerability and easiness to formulation. For this purpose we prepared two different systems using semisynthetic Hyaluronic Acid (HA) benzyl ester and a synthetic polymer (patent pending). We obtained these systems using two different methodologies: emulsification/solvent evaporation and emulsification/solvent extraction. The comparison between the two formulated systems was carried out in terms of their chemical-physical and biological properties.

Capsules↗
PubMed1995

A randomized trial of two preparations of vaginal prostaglandin for pre-induction cervical ripening.

OBJECTIVE: To compare two prostaglandin (PG) E2 preparations for pre-induction cervical ripening in a randomized clinical trial. METHODS: Two milligrams of vaginal PGE2 gel was compared with a vaginal PGE2 3-mg tablet in 200 nulliparous women. Outcomes assessed were induction failure, need for labor augmentation, pain relief requirements, fetal heart rate (FHR) abnormalities, operative delivery rate, induction-to-delivery interval, neonatal condition, and occurrence of uterine hyperstimulation. RESULTS: There was no statistical difference in pre- and post-dose cervical scores. Compared with the tablet group, women in the gel group were more likely to have significant FHR abnormalities in early labor (odds ratio [OR] 4.77, 95% confidence interval [CI] 1.15-19.5) requiring cesarean delivery. Fetal heart rate tracings in the active phase of labor were also more likely to be abnormal in the gel group (chi 2 = 4.31, P < .05). Compared with the gel group, women in the tablet group were significantly more likely to require operative delivery for poor progress in labor (OR 2.83, 95% CI 1.20-7.24). Other clinical outcomes were identical, with no significant differences in the overall rate of failed induction, cesarean delivery, rate of assisted delivery, requirement for oxytocin infusion, induction-to-delivery interval, pain relief requirements, or neonatal condition. CONCLUSIONS: When compared with the PGE2 tablet, the use of PGE2 gel for cervical ripening and labor induction in nulliparous women did not result in significant improvements in labor outcome. Whereas the gel was associated with an increase in significant FHR abnormalities, the tablet was associated with an increase in the rate of operative delivery for poor progress in labor.

Alprostadil↗
PubMed1991

The mitochondrial genome of Schizosaccharomyces pombe. Stimulation of intra-chromosomal recombination in Escherichia coli by the gene product of the first cox1 intron.

The open reading frame of the first intron of the mitochondrial cox1 gene (cox1I1) was expressed in Escherichia coli. The putative intron-encoded protein stimulated the formation of intra-chromosomal lac(+)-recombinants about threefold. No stimulation was found when the reading frame was inserted in the opposite direction, or when it was interrupted by a deletion. The intronic open reading frame did not complement recA- or recB- mutants of E. coli. In S. pombe, elimination of this intron did not abolish homologous recombination in mitochondria. A possible role of the recombinase activity in yeast mitochondria will be discussed.

Amino Acid Sequence↗
PubMedDate not supplied

A neuronal modeling paradigm in the presence of refractoriness.

A mathematical characterization of the membrane potential as an instantaneous return process in the presence of refractoriness is investigated for diffusion models of single neuron's activity, assuming that the firing threshold acts as an elastic barrier. Steady-state probability densities and asymptotic moments of the neuronal membrane potential are explicitly obtained in a form that is suitable for quantitative evaluations. For the Ornstein-Uhlenbeck (OU) and Feller neuronal models, closed form expression are obtained for asymptotic mean and variance of the neuronal membrane potential and an analysis of the different features exhibited by the above mentioned models is performed.

Models, Neurological↗