Estudi d'impacte ac��stic de les obres d'un intercanviador de metro

En el territori del Barcelon��s les obres han estat a l���ordre del dia. Abans de l���inici de la crisi es van encetar i programar nombroses obres tan d���immobles com de grans infraestructures com la que aqu�� es presenta: un intercanviador de metro. L���alta densitat demogr��fica d���aquesta regi�� ha fet que aquests treballs realitzats a les obres siguin poc compatibles amb el benestar i la salut de la poblaci��. Un dels principals factors causants del malestar als ve��ns ��s el soroll. Mitjan��ant estudis de modelitzaci�� ac��stica, com el realitzat en aquest projecte, es pret��n preveure i evitar que l���afecci�� ac��stica derivada de les obres sigui perjudicial per la persona per tal de compatibilitzar al m��xim possible les feines de l���obra amb el benestar general. Mitjan��ant el programa de monitoritzaci�� ac��stica Cadna���A i nombroses mesures ac��stiques in situ s���ha pogut preveure la futura afecci�� sonora de 6 fases d���obra considerades com les m��s sorolloses i s���han proposat un seguit de mesures preventives i/o correctores per tal d���assolir uns nivells ac��stics assequibles amb la legislaci�� vigent.

A system-level, molecular evolutionary analysis of mammalian phototransduction

Visual perception is initiated in the photoreceptor cells of the retina via the phototransduction system.This system has shown marked evolution during mammalian divergence in such complex attributes as activation time and recovery time. We have performed a molecular evolutionary analysis of proteins involved in mammalianphototransduction in order to unravel how the action of natural selection has been distributed throughout thesystem to evolve such traits. We found selective pressures to be non-randomly distributed according to both a simple protein classification scheme and a protein-interaction network representation of the signaling pathway. Proteins which are topologically central in the signaling pathway, such as the G proteins, as well as retinoid cycle chaperones and proteins involved in photoreceptor cell-type determination, were found to be more constrained in their evolution. Proteins peripheral to the pathway, such as ion channels and exchangers, as well as the retinoid cycle enzymes, have experienced a relaxation of selective pressures. Furthermore, signals of positive selection were detected in two genes: the short-wave (blue) opsin (OPN1SW) in hominids and the rod-specific Na+/Ca2+,K+ ion exchanger (SLC24A1) in rodents. The functions of the proteins involved in phototransduction and the topology of the interactions between them have imposed non-random constraints on their evolution. Thus, in shaping or conserving system-level phototransduction traits, natural selection has targeted the underlying proteins in a concerted manner.

TRPM5-mediated calcium uptake regulates mucin secretion from human colon goblet cells

Mucin 5AC (MUC5AC) is secreted by goblet cells of the respiratory tract and, surprisingly, also expressed de novo in mucus secreting cancer lines. siRNA-mediated knockdown of 7343 human gene products in a human colonic cancer goblet cell line (HT29-18N2) revealed new proteins, including a Ca(2+)-activated channel TRPM5, for MUC5AC secretion. TRPM5 was required for PMA and ATP-induced secretion of MUC5AC from the post-Golgi secretory granules. Stable knockdown of TRPM5 reduced a TRPM5-like current and ATP-mediated Ca(2+) signal. ATP-induced MUC5AC secretion depended strongly on Ca(2+) influx, which was markedly reduced in TRPM5 knockdown cells. The difference in ATP-induced Ca(2+) entry between control and TRPM5 knockdown cells was abrogated in the absence of extracellular Ca(2+) and by inhibition of the Na(+)/Ca(2+) exchanger (NCX). Accordingly, MUC5AC secretion was reduced by inhibition of NCX. Thus TRPM5 activation by ATP couples TRPM5-mediated Na(+) entry to promote Ca(2+) uptake via an NCX to trigger MUC5AC secretion