Natural Ventilation by Air Captors and Extractors Sheds in Hospitals in Brazil： Wind Tunnel Measurements

Natural ventilation is an efficient design strategy for the passive cooling of buildings, especially in tropical countries such as Brazil. Among the ventilation strategies, sheds can be highlighted. These structures consist of roof openings that work as air captors or extractors depending on their location in relation to the prevailing wind directions. The hospitals of the Sarah Network, designed by the Brazilian architect Joao Filgueiras Lima, Lele, are worldwide known for using these elements to improve natural ventilation. This paper analyses the natural ventilation performance of sheds for air collecting and extracting in two Sarah hospitals located in the cities of Salvador and Rio de Janeiro. In each building, the sheds were analyzed for air extracting and collecting. The analyses were carried out by reduced physical models in an atmospheric boundary layer wind tunnel. The wind velocity was measured at external and internal points of the buildings, using hot-wire anemometers. The results show that the wards in Rio de Janeiro hospital are 17% more ventilated than the ones in the Salvador hospital. However, this difference occurs not only because of the collecting sheds but also because of set of openings and the configuration of the covering in hospitals in Rio de Janeiro.     

A Chimeric UDP-Glucose Pyrophosphorylase Produced by Protein Engineering Exhibits Sensitivity to Allosteric Regulators

In bacteria, glycogen or oligosaccharide accumulation involves glucose-1-phosphate partitioning into either ADP-glucose (ADP-Glc) or UDP-Glc. Their respective synthesis is catalyzed by allosterically regulated ADP-Glc pyrophosphorylase (EC 2.7.7.27, ADP-Glc PPase) or unregulated UDP-Glc PPase (EC 2.7.7.9). In this work, we characterized the UDP-Glc PPase from Streptococcus mutans. In addition, we constructed a chimeric protein by cutting the C-terminal domain of the ADP-Glc PPase from Escherichia coli and pasting it to the entire S. mutans UDP-Glc PPase. Both proteins were fully active as UDP-Glc PPases and their kinetic parameters were measured. The chimeric enzyme had a slightly higher affinity for substrates than the native S. mutans UDP-Glc PPase, but the maximal activity was four times lower. Interestingly, the chimeric protein was sensitive to regulation by pyruvate, 3-phosphoglyceric acid and fructose-1,6-bis-phosphate, which are known to be effectors of ADP-Glc PPases from different sources. The three compounds activated the chimeric enzyme up to three-fold, and increased the affinity for substrates. This chimeric protein is the first reported UDP-Glc PPase with allosteric regulatory properties. In addition, this is a pioneer work dealing with a chimeric enzyme constructed as a hybrid of two pyrophosphorylases with different specificity toward nucleoside-diphospho-glucose and our results turn to be relevant for a deeper understanding of the evolution of allosterism in this family of enzymes.     

Identification of residues responsible for the selective binding of peptide antagonists and agonists in the V2 vasopressin receptor

To improve our understanding of the functional architecture of G protein-coupled receptors, we have taken advantage of differences among mammalian species in ligand binding to search for the rat versus human selectivity determinants of the V2 vasopressin receptor and of its peptide ligands. Our data indicate that residue 2 of species-selective peptide antagonists such as d(CH2)5-[D-Ile2,Ile4, Tyr-NH29]arginine vasopressin controls their rat versus human selectivity. For species-selective agonists such as desmopressin, residues 1 and 8 modulate the binding selectivity. Among residues different between rat and human V2 receptors, those localized in the upper part of the human V2 receptor have been substituted with their rat V2 homologs. Pharmacological analysis of mutant receptors revealed that residues 202 and 304 fully control the species selectivity of the discriminating antagonists in an independent and additive manner. A third residue (position 100) is necessary to observe an equivalent phenomenon for the discriminating agonists. The substitution of these three residues does not modify the affinity of the nonselective agonists and antagonists. In conclusion, extracellular loops and the top of the transmembrane domains of V2 vasopressin receptors may provide the molecular basis for peptide ligand-binding species selectivity. Very few residues in these regions may control the binding mode of both agonists and antagonists.     

Release of [14C]adenosine derivatives from superfused synaptosome preparations. Effects of depolarizing agents and metabolic inhibitors

Adenine 5'-mononucleotides of synaptosome beds from guinea pig neocortex were labelled by incubation with [8-(14)C]adenosine, and excess adenosine was then removed with precursor-free medium. During continuous superfusion, labelled adenosine derivatives were released at a rate of about 0.5% of the synaptosome 14C/min and this rate was increased 2.5-fold by depolarization with 33 mM K+. Some depolarizing agents and metabolic inhibitors were examined for action on the release of [14C)-adenosine derivatives from the synaptosome preparations, and also on the rate of lactate production by these preparations, both before and during K + depolarization. The synaptosome content of adenine 5'-mononucleotides following exposure of the synaptosome beds to these compounds was also estimated. Ouabain, 0.1 mM, brought about an increase in 14C-labelled compounds output, but it caused little alteration in lactate output and some decrease in the adenylate energy charge of the synaptosomes. Veratridine, 80 microM, increased markedly both the output of radioactivity and the lactate production. Tetrodotoxin, 1 microM, when added together with veratridine, completely abolished the effect of veratridine on the efflux of [14C]adenosine derivatives, but this was not associated with a complete blockade of the output of lactate. Sodium cyanide, 2.5 mM, FCCP, 6 muM together with iodoacetate, 2.5 mM, caused an increase in the output of 14C-labelled compounds, and a decrease in the adenylate energy charge. The production of lactate was also increased by sodium cyanide and FCCP, but it was completely inhibited by iodoactate. Oligomycin, 4.65 microM, and amytal, 1 mM, added in the incubation medium before labelling the synaptosome beds with [8-(14)C]adenosine, did not affect very much the output of [14C]adenosine derivatives, while the output of lactate increased independently of the depolarization with 33 mM K+. The release of adenosine derivatives from superfused synaptosome beds induced by depolarizing agents or metabolic inhibitors did not seem to be due either to an effect of membrane permeability changes that follow a decrease of ATP supply, or to an increased metabolic rate occurring during nerve ending stimulation. It is concluded that this release of adenosine derivatives appeared to be a process triggered primarily by the influx of Na+ and the increased intrasynaptosomal calcium, and closely related to the process of neurotransmission.     

Implementation of Lean and Green practices: a supplier-oriented assessment method

Organizations are being pressured to increase productivity, while reducing costs and improving quality. In this matter, lean manufacturing (LM) has been widely adopted by firms to reduce waste and achieve such improvements. However, the shortage of natural resources and the high levels of pollution have forced these organizations to meet several regulations for the control of environmental impacts. In addition, organizations’ environmental initiatives have become a critical factor for market differentiation. The integration of both LM and environmental management (EM) results in an innovative approach, called Lean and Green. Much has been studied about synergies and divergences among LM and EM practices. However, there is still a gap regarding the assessment of the level of integration between both approaches. This research aims at proposing a method for assessing the implementation level of LM and EM practices specifically related to suppliers’ relationship. The proposed method allows the identification of critical practices that corroborate for a synergic implementation of lean and Green approach. Further, these practices are ranked enabling managers to prioritize their improvement initiatives. Our results indicate that for a few practices some trade-offs might emerge according to the type of product, entailing a certain level of adaptation to attend to environmental demands.     

Detecting inappropriate access to electronic health records using collaborative filtering

Many healthcare facilities enforce security on their electronic health records (EHRs) through a corrective mechanism: some staff nominally have almost unrestricted access to the records, but there is a strict ex post facto audit process for inappropriate accesses, i.e., accesses that violate the facility’s security and privacy policies. This process is inefficient, as each suspicious access has to be reviewed by a security expert, and is purely retrospective, as it occurs after damage may have been incurred. This motivates automated approaches based on machine learning using historical data. Previous attempts at such a system have successfully applied supervised learning models to this end, such as SVMs and logistic regression. While providing benefits over manual auditing, these approaches ignore the identity of the users and patients involved in a record access. Therefore, they cannot exploit the fact that a patient whose record was previously involved in a violation has an increased risk of being involved in a future violation. Motivated by this, in this paper, we propose a collaborative filtering inspired approach to predicting inappropriate accesses. Our solution integrates both explicit and latent features for staff and patients, the latter acting as a personalized “fingerprint” based on historical access patterns. The proposed method, when applied to real EHR access data from two tertiary hospitals and a file-access dataset from Amazon, shows not only significantly improved performance compared to existing methods, but also provides insights as to what indicates an inappropriate access.     

Left endoatrial myxoma. Notes on a case

A case of left endoatrial mixoma, ecocardiographically discovered and successfully operated, is reported. The usefulness of ecocardiography, especially to discover intracardiac masses, is considered.