1,721,149 research outputs found

    Il fenomeno migratorio

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    I flussi migratori non sono omogenei. Non tutto il territorio nazionale è interessato in egual misura. Lo studio cerca di porre in risalto le peculiarità del territorio Massese con rferimento alle provenienze dal continente african

    mechanism of human sperm activation by extracellular atp

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    We have identified the mechanism whereby extracellular ATP (ATPe) triggers the acrosome reaction in human spermatozoa. This nucleotide opens a ligand-gated ion channel expressed on the sperm plasma membrane. ATPe threshold and 50% effective concentration calculated on the total added ATPe are 0.1 and 2 mM, respectively, corresponding to a free ATP concentration (ATP4-) of 3 and 200 microM, respectively. The ATPe-gated channel is selective for monovalent cations (Na+, choline, and methylglucamine), whereas on the contrary, permeability to Ca2+ is negligible. Isosmolar replacement of extracellular Na+ with sucrose fully blocked ATPe-dependent sperm activation, thus suggesting a mandatory role for Na+ influx. These results show that human sperm express an ATPe-gated Na+ channel that might have an important role in sperm activation before egg fertilization

    Postural evaluation in young skaters: effect of two proprioceptive training

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    The roller skating involves developing of motor and artistic skills from an early age. The aim was to evaluate the effects that an ocular a podalic proprioceptive training cause to postural control and stability in a sample of young skaters. A total of 25 skaters aged between 9 and 15 (12±2.14) divided into two groups: the eyes group (EG) aimed at exercising visual proprioception, the feet group (FG) aimed at exercising podalic proprioception. The participants were subject to through electronic stabilometry in static mode, open (OE) and closed (CE) eyes, in a time T0 (pre-training) and T1 (post-training), without and with skates. The results through the two paired t-test showed that both variables Wz (TotHz) to CE within the EG (p<.05) and Wx (TotHz) to CE within the FG (p<.05) were statistical significance. The unpaired t-test showed that the FG obtained a greater statistical significance than the EG for the VarVit and Wx (TotHz) variables in CE (p<.05) and Wz (TotHz) in both CE and OE (p<.05). The two-way ANOVA found statistical significance (p<.05) on the Wx (TotHz) variable in open/closed eyes of the FG (T0/T1). We concluded that in roller skating it could be useful to integrate athletic training with a visual proprioceptive training.

    COVID-19 and smoking habits: A smoky situation!

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    Dear Editor, the issues recently raised by Carratù et al. on the role of smoking/former smoking in patients hospitalized for COVID-19 all around the world as widely reported in many different published papers, are important for different reasons..
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