Influence of flow variation on fixed-time signal control

The purpose of this thesis is to analyze the effects of fluctuation in traffic flows on the operation of fixed-time control systems. In the development of fixed time plans for area traffic control, traffic volumes reflecting average conditions for the movements at all intersections are normally required. Calculations made on basis of these values commonly overestimate the benefits of the implementation of fixed-time signal control plans because the variability of flows is not taken into account. The day-to-day, or between-days variation of traffic, is not normally considered in fixed-time plans and the daily systematic fluctuation, or within-day variation of traffic, is handled by the adoption of one of several possible procedures. In practice, single observations of flow are commonly used in place of the mean, and flows in different parts of the same network are sometimes observed on different days. The consequences of this practice are analyzed in view of the variability of traffic flows. In this thesis an analysis of the techniques currently available to handle traffic fluctuation by fixed-time control systems is made. Ways are investigated in which some measure of variability of traffic flows can be respected in the calculation of fixed-time signal plans. A method that incorporates the variability of the traffic flows in the calculation of a single fixed-time plan is developed. This was based on theoretical values and validated with real flows, collected in a purpose-specific field survey. The technique developed in this research has been found to improve the efficiency of the fixed-time systems in handling both of these kinds of variation. Using explicit conditions of a variety of traffic flows on each link, this technique is suitable to be used as a standard feature for calculation of fixed-time signal plans which will be used under a range of traffic conditions. The problem of the cycle time selection is analyzed and comparisons are made between the performance of the network, using cycle times suggested by the approximate method incorporated in TRANSYT, and those selected on the basis of full day by day optimisation by this program

Minimally processed fruit salad enriched with Lactobacillus acidophilus: Viability of anti-browning compounds in the preservation of color

Minimal processing promotes browning of some vegetal tissues due to cell membrane disruption, which results in the release of oxidative enzymes. This study evaluated the efficiency of citric acid, ascorbic acid, sodium metabisulfite and L-cysteine hydrochloride to retard enzymatic browning of minimally processed fruit salad and enriched this product with Lactobacillus acidophilus LA-5. Control treatment was fruit salad immersed in water. Polyphenol oxidase (PPO) and color (L*, a*, b*, index color - CI, browning index - BI, c*, and h°) were analyzed. The viability of L. acidophilus was also evaluated using Rogosa agar in fruit salads containing anti-browning compounds in higher concentrations. PPO presented a significant difference among control and fruit salad treated with ascorbic acid and L-cysteine hydrochloride, indicating the highest anti-browning activity of these compounds. The fruit color was affected by processing and storage time, with a reduction in the values of L* over time. Values of a*, c*, h° angle and CI indicated a predominance of red color in the fruit salad. Salads containing anti-browning compounds in higher concentrations presented viability of L. acidophilus above 7.43 log CFU/g up to the fifth day of storage, indicating that the product can be promised as probiotic. Thus, the fruit salad treated with anti-browning compounds has potential use as a probiotic carrier.Keywords: Fresh-cut fruits, color, ascorbic acid, vegetable matrix, probiotic culture

Development of a quartz tuning-fork-based force sensor for measurements in the tens of nanoNewton force range during nanomanipulation experiments

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Understanding the mechanical properties of nanoscale systems requires new experimental and theoretical tools. In particular, force sensors compatible with nanomechanical testing experiments and with sensitivity in the nN range are required. Here, we report the development and testing of a tuning-fork-based force sensor for in situ nanomanipulation experiments inside a scanning electron microscope. The sensor uses a very simple design for the electronics and it allows the direct and quantitative force measurement in the 1-100 nN force range. The sensor response is initially calibrated against a nN range force standard, as, for example, a calibrated Atomic Force Microscopy cantilever; subsequently, applied force values can be directly derived using only the electric signals generated by the tuning fork. Using a homemade nanomanipulator, the quantitative force sensor has been used to analyze the mechanical deformation of multi-walled carbon nanotube bundles, where we analyzed forces in the 5-40 nN range, measured with an error bar of a few nN. (C) 2014 AIP Publishing LLC.853Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2010/51028-4]CNPq [476458/2011-0

Dynamic Allostery in PLC gamma 1 and Its Modulation by a Cancer Mutation Revealed by MD Simulation and NMR

Phosphatidylinositol phospholipase Cγ (PLCγ) is an intracellular membrane-associated second-messenger signaling protein activated by tyrosine kinases such as fibroblast growth factor receptor 1. PLCγ contains the regulatory γ-specific array (γSA) comprising a tandem Src homology 2 (SH2) pair, an SH3 domain, and a split pleckstrin homology domain. Binding of an activated growth factor receptor to γSA leads to Tyr783 phosphorylation and consequent PLCγ activation. Several disease-relevant mutations in γSA have been identified; all lead to elevated phospholipase activity. In this work, we describe an allosteric mechanism that connects the Tyr783 phosphorylation site to the nSH2-cSH2 junction and involves dynamic interactions between the cSH2-SH3 linker and cSH2. Molecular dynamics simulations of the tandem SH2 protein suggest that Tyr783 phosphorylation is communicated to the nSH2-cSH2 junction by modulating cSH2 binding to sections of the cSH2-SH3 linker. NMR chemical shift perturbation analyses for designed tandem SH2 constructs reveal combined fast and slow dynamic processes that can be attributed to allosteric communication involving these regions of the protein, establishing an example in which complex N-site exchange can be directly inferred from 1H,15N-HSQC spectra. Furthermore, in tandem SH2 and γSA constructs, molecular dynamics and NMR results show that the Arg687Trp mutant in PLCγ1 (equivalent to the cancer mutation Arg665Trp in PLCγ2) perturbs the dynamic allosteric pathway. This combined experimental and computational study reveals a rare example of multistate kinetics involved in a dynamic allosteric process that is modulated in the context of a disease-relevant mutation. The allosteric influences and the weakened binding of the cSH2-SH3 linker to cSH2 should be taken into account in any more holistic investigation of PLCγ regulation

Piperacillin-Tazobactam Anaphylaxis: a Rare Cause of Occupational Disease

Piperacillin is a beta-lactam antibiotic of penicillin family. Some penicillins were report-ed as occupational diseases cause, but piperacillin anaphylaxis with occupational sensi-tization is rare. We describe the case of a female nurse with recurrent anaphylaxis in last few months without apparent cause, only in work environment. Latex allergy was excluded after negative latex glove provocation. Later during diagnostic workup, the patient reported a similar reaction minutes after piperacillin preparation. She denied any previous antibiotic therapeutic exposure. Skin prick tests (SPT) to beta-lactams were positive to piperacillin, penicillin G and major and minor determinants. SPT to cefuroxime was negative but intradermic test was positive. The patient has indication for beta-lactams eviction and for adrenaline auto-injector kit. No further reactions occurred after patient's transfer to another department with minimum possible exposure. Allergic risk prevention is essential and must be rapidly implemented to avoid incapacitating occupational diseases development.info:eu-repo/semantics/publishedVersio

Chiral Polymerization in Open Systems From Chiral-Selective Reaction Rates

We investigate the possibility that prebiotic homochirality can be achieved exclusively through chiral-selective reaction rate parameters without any other explicit mechanism for chiral bias. Specifically, we examine an open network of polymerization reactions, where the reaction rates can have chiral-selective values. The reactions are neither autocatalytic nor do they contain explicit enantiomeric cross-inhibition terms. We are thus investigating how rare a set of chiral-selective reaction rates needs to be in order to generate a reasonable amount of chiral bias. We quantify our results adopting a statistical approach: varying both the mean value and the rms dispersion of the relevant reaction rates, we show that moderate to high levels of chiral excess can be achieved with fairly small chiral bias, below 10%. Considering the various unknowns related to prebiotic chemical networks in early Earth and the dependence of reaction rates to environmental properties such as temperature and pressure variations, we argue that homochirality could have been achieved from moderate amounts of chiral selectivity in the reaction rates.Comment: 15 pages, 6 figures, accepted for publication in Origins of Life and Evolution of Biosphere

Histomorphometric and immunohistochemical analysis of infectious agents, T-cell subpopulations and inflammatory adhesion molecules in placentas from HIV-seropositive pregnant women

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to compare histomorphometric changes and the results of immunohistochemical tests for VCAM, ICAM-1, CD4 and CD8 in normal placentas from HIV-seropositive pregnant women.</p> <p>Methods</p> <p>Samples of normal placentas were divided into 2 groups: healthy HIV-seronegative pregnant women (control group = C = 60) and HIV-seropositive women (experimental group = E = 57). Conventional histological sections were submitted to morphometric analysis and evaluated in terms of the immunohistochemical expression of ICAM-1, VCAM, CD4 and CD8.</p> <p>Results</p> <p>The villi in group E were smaller than those in group C. The median for the CD8+ T cell count was higher in group E than in group C (p = 0.03). Immunohistochemical expression of ICAM-1 was observed in 57% of the cases in group E, compared with 21% of those in group C (p = 0.001). There was no difference in VCAM expression or CD4+ cell counts between groups and no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data.</p> <p>Conclusions</p> <p>The morphometric data showed that placentas of HIV-seropositive pregnant women tend to have smaller villi than those of seronegative women. In addition, immunohistochemical testing for infectious agents helped to identify cases that were positive for microorganisms (6/112) that routine pathological examination had failed to detect. The anti-p24 antibody had a limited ability to detect HIV viral protein in this study (2/57). Correlation of immunohistochemical expression of CD8+ T cells and ICAM-1 with the presence of HIV in the placenta revealed that those expressions can act as biomarkers of inflammatory changes. There was no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data.</p