Prediction of leak flow rate in plastic water distribution pipes using vibro-acoustic measurements

Leakage from water distribution systems is a worldwide issue with consequences including loss of revenue, health and environmental concerns. Leaks have typically been found through leak noise correlation by placing sensors either side of the leak and recording and analysing its vibro-acoustic emission. While this method is widely used to identify the location of the leak, the sensors also record data that could be related to the leak’s flow rate, yet no reliable method exists to predict leak flow rate in water distribution pipes using vibro-acoustic emission. The aim of this research is to predict leak flow rate in medium-density polyethylene pipe using vibro-acoustic emission signals. A novel experimental methodology is presented whereby circular holes of four sizes are tested at several leak flow rates. Following the derivation of a number of features, least squares support vector machines are used in order to predict leak flow rate. The results show a strong correlation highlighting the potential of this technique as a rapid and practical tool for water companies to assess and prioritise leak repair

Viruses: incredible nanomachines. New advances with filamentous phages

During recent decades, bacteriophages have been at the cutting edge of new developments in molecular biology, biophysics, and, more recently, bionanotechnology. In particular filamentous viruses, for example bacteriophage M13, have a virion architecture that enables precision building of ordered and defect-free two and three-dimensional structures on a nanometre scale. This could not have been possible without detailed knowledge of coat protein structure and dynamics during the virus reproduction cycle. The results of the spectroscopic studies conducted in our group compellingly demonstrate a critical role of membrane embedment of the protein both during infectious entry of the virus into the host cell and during assembly of the new virion in the host membrane. The protein is effectively embedded in the membrane by a strong C-terminal interfacial anchor, which together with a simple tilt mechanism and a subtle structural adjustment of the extreme end of its N terminus provides favourable thermodynamical association of the protein in the lipid bilayer. This basic physicochemical rule cannot be violated and any new bionanotechnology that will emerge from bacteriophage M13 should take this into account

NMR structure of PW2 bound to SDS micelles - A tryptophan-rich anticoccidial peptide selected from phage display libraries

PW2 (HPLKQYWWRPSI) was selected from phage display libraries through an alternative panning method using living sporozoites of Eimeria acervulina as target. Synthetic PW2 shows anticoccidial activity against E. acervulina and Eimeria tenella with very low hemolytic activity. It also displays antifungal activity but no activity against bacteria. We present the solution structure of the PW2 bound to SDS micelles. In the absence of an interface, PW2 is in random coil conformation. In micelles, structural calculation shows that Trp-7 forms the hydrophobic core that is important for the peptide folding. Lys-4, Tyr-6, Trp-8, and Arg-9 are in the same surface, possibly facing the micelle interface. This possibility was supported by the fact that chemical shift differences for these residues were more pronounced when compared with PW2 in water and in SDS. PW2 gains structure upon binding to SDS micelles. Lys-4, Tyr-6, Trp-8, and Arg-9 were found to bind to the micelle. Trp-7, Trp-8, and Arg-9 composed the WW+ consensus found in the sequence of the peptides selected with the phage display technique against E. acervulina sporozoites. This suggested that Trp-7, Trp-8, and Arg-9 are probably key residues not only for the peptide interaction with SDS micelles but also for the interaction with E. acervulina sporozoites surface.27739363513635

The bZIP region of the plant transcription factor opaque-2 forms stable homodimers in solution and retains its helical structure upon subunit dissociation

Opaque-2 (O2) is a plant bZIP transcription factor that regulates the expression of alpha and beta prolamines, the main storage proteins in seeds of cereals such as maize and Coix. One of the main processes modulating O2 activity is the heterodimerization with other bZIP transcription factors, but the primary mechanism underlying the partner choice is still unknown. In this paper, we have characterized the bZIP domain of O2 by nuclear magnetic resonance (NMR), circular dichroism (CD), and size-exclusion chromatography. Results obtained from CD measurements suggested that the native O2bZIP has about 40 of its 49 leucine-zipper residues in helical structure, while the DNA-binding domain is completely unstructured. Diffusion-ordered NMR spectroscopy and size-exclusion chromatography showed that O2 forms homodimers in solution. Thermal denaturation experiments indicate that O2 reversibly undergoes dissociation and unfolding in a process that is fully dependent on the protein concentration. Subunit dissociation of O2bZIP dimers, upon dilution of the protein, led to partially folded monomers that retained similar to80% of the native CD ellipticity at 222 net. We believe that the existence of partially folded monomers could decrease the entropic penalty for helix formation involved in the DNA binding and in the subunit association of O2bZIP. Stabilization of partially folded monomers may also play a significant role in the dimerization of O2 with other bZIP transcription factors and, consequently, can be important for the regulation of the biological functions of O2 in plants.43164862486

Governança no MERCOSUL: uma análise em temas contemporâneos

This article provides a brief analysis is of governance within MERCOSUL, addressing two issues relevant to contemporary international agenda: the use of the Guarani Aquifer, within the environmental issues, and Internet governance, in security and technology fields. Wanted highlight the agreements made so far and the main actors involved in the recent regional efforts for such discussions.Este artigo traz uma breve análise sobre governança dentro do MERCOSUL, abordando dois temas pertinentes à agenda internacional contemporânea: o uso do Aquífero Guarani, dentro das temáticas ambientais, e a governança da Internet, nos campos de segurança e tecnologia. Procura-se destacar os acordos feitos até agora e os principais atores envolvidos nos recentes esforços regionais para tais discussões

Governança no MERCOSUL: uma análise em temas contemporâneos

This article provides a brief analysis is of governance within MERCOSUL, addressing two issues relevant to contemporary international agenda: the use of the Guarani Aquifer, within the environmental issues, and Internet governance, in security and technology fields. Wanted highlight the agreements made so far and the main actors involved in the recent regional efforts for such discussions.Este artigo traz uma breve análise sobre governança dentro do MERCOSUL, abordando dois temas pertinentes à agenda internacional contemporânea: o uso do Aquífero Guarani, dentro das temáticas ambientais, e a governança da Internet, nos campos de segurança e tecnologia. Procura-se destacar os acordos feitos até agora e os principais atores envolvidos nos recentes esforços regionais para tais discussões

Thermodynamic and Structural Characterization of Zwitterionic Micelles of the Membrane Protein Solubilizing Amidosulfobetaine Surfactants ASB-14 and ASB-16

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Surface tension and isothermal titration calorimetry (ITC) were used to determine the critical micelle concentration (cmc) of the zwitterionic amidosulfobetaine surfactants ASB-14 and ASB-16 (linear-allcylamidopropyldi-methylammoniopropanosulfonates) at 25 degrees C. The cmc and the heat of micellizabon were determined from 15 to 75 degrees C by ITC for both surfactants. The increase in temperature caused significant changes in the enthalpy and in the entropy of micellization, with small changes in the standard Gibbs energy (Delta G(mic)), which is consistent to an enthalpy-entropy compensation with a compensatory temperature of 311 K (ASB-14) and 314 K (ASB-16). In the studied temperature range, the heat capacity of micellization (Delta C(p)(mic)) was essentially constant. The experimental Delta C(p)(mic) was lower than that expected if only hydrophobic interactions were considered, suggesting that polar interactions at the head groups are of significant importance in the thermodynamics of micelle formation by these surfactants. Indeed, a NMR NOESY spectrum showed NOES that are improbable to occur within the same monomer, resulting from interactions at the polar head groups involving more than one monomer. The ITC and NMR results indicate a tilt in the polar headgroup favoring the polar interactions. We have also observed COSY correlations typical of dipolar interactions that could be recovered with the partial alignment of the molecule in solution, which results in an anisotropic tumbling. The anisotropy suggested an ellipsoidal shape of the micelles, which results in a positive magnetic susceptibility, and ultimately in orientation induced by the magnetic field. Such an ellipsoidal shape was confirmed from results obtained by SAXS experiments that revealed aggregation numbers of 108 and 168 for ASB-14 and ASB-16 micelles, respectively. This study characterizes an interesting micelle system that can be used in the study of membrane proteins by solution NMR. spectroscopy.271382488256Financiadora de Estudos e Projetos (FINEP/CT-Infra)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES