Transient ischemic attacks in Chilean patients and their relationship with the country''s pattern of cerebrovascular disease

For the globular proteins with known three-dimensional structures, an ellipsoid model of each protein was constructed with least volume and its dimensions were derived. The spatial arrangements were made for the C alpha and side chain atoms of that protein within that ellipsoid. This new spatial representation shows the residue position from the centroid, as well as the depth from the surface. The average spatial parameters were then calculated. The correlations between these new spatial parameters and the existing parameters of the amino acid residues were then derived.     

Cytotoxic T cell responses to DNA vaccination: dependence on antigen presentation via class II MHC

This study was designed to test whether cytotoxic T cell (CTL) responses to DNA vaccination are dependent upon MHC class II-restricted priming of CD4+ T cells. Because DNA vaccination may directly transfect dendritic cells, and dendritic cells may be capable of directly stimulating CD8+ T cell responses, such priming might be unnecessary. To test this hypothesis, C57BL/6 mice were immunized intramuscularly or intradermally with DNA encoding either whole OVA, a class I (Kb)-restricted peptide epitope of OVA (amino acids 257-264, SIINFEKL), or this class I-restricted epitope plus the adjacent class II (I-Ab)-restricted epitope of OVA (amino acids 265-280, TEWTSSNVMEERKIKV). Very low to negligible CTL responses were observed in mice vaccinated with the SIINFEKL construct, whereas mice vaccinated with the SIINFEKLTEWTSSNVMEERKIKV or with the complete OVA construct made equally robust CTL responses. These responses were sensitive to blocking by anti-CD8 mAb and were shown to be SIINFEKL-specific by using SIINFEKL peptide-pulsed EL-4 cells as targets. To ensure that the generation of these CTL responses was indeed dependent upon CD4+ T cell help, mice were depleted of either CD4+ or CD8+ cells before immunization. Depletion of CD4+ cells completely abrogated the CTL response to OVA DNA, as did depletion of CD8+ cells. Thus, we conclude that the CTL response to both intramuscular and intradermal DNA vaccination is highly dependent upon the generation of CD4+ T cell help via a class II MHC-dependent pathway. These results will be relevant for the construction of minimal-epitope vaccines for DNA immunization.     

Optical mode cleaner with suspended mirrors

We report on the development of a new type of mode cleaner that reduces any geometric noise of the laser beam in an interferometric gravitational-wave detector. The mode cleaner is a Fabry-Perot cavity that comprises independently suspended mirrors and works as a frequency-stabilization reference as well as a mode selector; the length of the cavity is 1 m. Stand-alone tests have shown at least a 30-dB reduction in the geometric fluctuation of the beam and a 60-dB reduction of the frequency noise of the laser. We have also succeeded in operating a 20-m Fabry-Perot prototype detector (at the National Astronomical Observatory, Tokyo, Japan) by using this mode cleaner.     

Impact of chemical oxidation on biological treatment of a primary municipal wastewater. 2. Effects of ozonation on kinetics of biological oxidation

Activated sludge biological oxidation of municipal wastewaters has been applied under different experimental conditions to observe the effect of preozonation on COD and process kinetics. In all cases, previous application of ozone allows significant improvement of COD level reduction during subsequent biological oxidation. Biomass concentration also exerts a positive influence on COD level reduction. Thus, 54 and 82% COD level reductions are achieved after biological oxidation without and with 30 minutes of preozonation. During the ozonation period, increase of pH from 2 to 9 leads to 15 to 24% COD level reductions, but biological oxidation should be followed at neutral pH since extreme conditions (pH 2 and 9) reduce considerably the biomass concentration and hence the yield of biodegradation. At the conditions investigated herein, there is an optimum ozone dose, 150 mg per liter of wastewater treated, that leads to the maximum COD level reduction in the combined process (chemical plus biological oxidation). Both single biological oxidation and combined with preozonation follows a Monod kinetic model assuming COD as the substrate of biomass. From kinetic results it is confirmed that a combination of chemical and biological oxidation leads to the highest maximum specific rates of COD consumption.     

Cellular growth of uterus, placenta and fetus during chronic maternal caloric restriction in rats

Wistar strain female rats were maintained with restricted amounts of 25% casein diet before and during pregnancy. Uteri, placentas and fetuses were removed from the rats beginning the 14th day of conception and continuing it up to the 20th day. Tissues were analyzed in regard to weight, nucleic acids and protein content. A 25% food restriction decreased dramatically the uterine, placental and fetal size as well as DNA content. RNA and protein content were also found diminished, but it must be emphasized that these findings were less important than the DNA content reduction observed. This is the reason why RNA/DNA and protein/DNA ratios were markedly elevated in regard to control values. Cellular changes observed in the reproductive organs and their relationships with fetal growth failure, induced by maternal dietary modification, are discussed.     

Modeling a mixed-integer-binary small-population evolutionary particle swarm algorithm for solving the optimal power flow problem in electric power systems

This research discusses the application of a mixed-integer-binary small-population-based evolutionary particle swarm optimization to the problem of optimal power flow, where the optimization problem has been formulated taking into account four decision variables simultaneously: active power (continuous), voltage generator (continuous), tap position on transformers (integer) and shunt devices (binary). The constraint handling technique used in the algorithm is based on a strategy to generate and keep the decision variables in feasible space through the heuristic operators. The heuristic operators are applied in the active power stage and the reactive power stage sequentially. Firstly, the heuristic operator for the power balance is computed in order to maintain the power balance constraint through a re-dispatch of the thermal units. Secondly, the heuristic operators for the limit of active power flows and the bus voltage constraint at each generator bus are executed through the sensitivity factors. The advantage of our approach is that the algorithm focuses the search of the decision variables on the feasible solution space, obtaining a better cost in the objective function. Such operators not only improve the quality of the final solutions but also significantly improve the convergence of the search process. The methodology is verified in several electric power systems.     

Humectants improve myosin extractability and water activity of raw, cured intermediate moisture meats

Glycerol, propylene glycol and sorbitol were incorporated into salt-based intermediate moisture meats manufactured from porcine M. longissimus thoracis and bovine M. biceps femoris by dry curing and air drying at 4°C. Moisture content and water activity (a(w)) in cured pork were reduced by the addition of propylene glycol and sorbitol. Propylene glycol was more effective than sorbitol in lowering a(w). The extractability of myosin heavy chain, used as an index of alteration of myofibrillar protein, decreased in intermediate moisture porcine meats with the addition of salt and was unaffected by sorbitol. However, use of glycerol and propylene glycol in cured and air-dried pork increased the extractability of myosin heavy chain. Whereas intact myofibrils could not be extracted from salt-cured, air-dried beef, myofibrils could be made from air-dried beef cured in the presence of 10% glycol, 5% propylene glycol and 4% sorbitol. Such myofibrils contracted immediately on addition of Mg(2+)-ATP. In addition, even after storafe for 5 months, including 30 days at 25°C, myosin heavy chain could be extracted from meat cured with this combination of humectants. In comparison with salt curing alone, curing meat with the above three humectants together, plus salt, results in intermediate moisture meats more like fresh meat.     

Effect of Ni addition and cryogenic hardening on the mechanical and tribological properties of self-lubricating steels produced by MIM

ABSTRACT

This paper addresses the relation between mechanical properties and tribological behaviour of self-lubricating steels produced by in-situ dissociation of SiC. Literature shows that an increase in the mechanical strength of these materials lowers their friction coefficient and wear rates. These works have studied steels with mechanical strength up to 800?MPa, but it is unclear if this trend continues with further increments of mechanical strengths. To tackle this question, self-lubricating steels with Ni and Mo were sintered, half of the samples with 8 wt-% Ni were treated cryogenically hardened. Results show that this trend does not escalate with mechanical strength, furthermore, when ductility is low, graphite reservoirs are not easily accessed, and lubrication is incomplete. Also, plastic deformation allows to better distribute the load of the counter body at the surface, which reduces the wear rates of the specimens and the counter bodies.     

How to reduce the number of rating scale items without predictability loss?

Rating scales are used to elicit data about qualitative entities (e.g., research collaboration). This study presents an innovative method for reducing the number of rating scale items without the predictability loss. The “area under the receiver operator curve method” (AUC ROC) is used. The presented method has reduced the number of rating scale items (variables) to 28.57% (from 21 to 6) making over 70% of collected data unnecessary. Results have been verified by two methods of analysis: Graded Response Model (GRM) and Confirmatory Factor Analysis (CFA). GRM revealed that the new method differentiates observations of high and middle scores. CFA proved that the reliability of the rating scale has not deteriorated by the scale item reduction. Both statistical analysis evidenced usefulness of the AUC ROC reduction method.