Influence of recycled aggregate quality and proportioning criteria on recycled concrete properties.

This paper presents the results of experimental research using concrete produced by substituting part of the natural coarse aggregates with recycled aggregates from concrete demolition. The influence of the quality of the recycled aggregate (amount of declassified and source of aggregate), the percentage of replacement on the targeted quality of the concrete to be produced (strength and workability) has been evaluated. The granular structure of concrete and replacement criteria were analyzed in this study, factors which have not been analyzed in other studies. The following properties of recycled concretes were analyzed: density, absorption, compressive strength, elastic modulus, amount of occluded air, penetration of water under pressure and splitting tensile strength. A simplified test program was designed to control the costs of the testing while still producing sufficient data to develop reliable conclusions in order to make the number of tests viable whilst guaranteeing the reliability of the conclusions. Several factors were analyzed including the type of aggregate, the percentage of replacement, the type of sieve curve, the declassified content, the strength of concrete and workability of concrete and the replacement criteria. The type of aggregate and the percentage of replacement were the only factors that showed a clear influence on most of the properties. Compressive strength is clearly affected by the quality of recycled aggregates. If the water-cement ratio is kept constant and the loss of workability due to the effect of using recycled aggregate is compensated for with additives, the percentage of replacement of the recycled aggregate will not affect the compressive strength. The elastic modulus is affected by the percentage of replacement. If the percentage of replacement does not exceed 50%, the elastic modulus will only change slightly.

Detección de Mycoplasma genitalium y correlación con manifestaciones clínicas en una población del estado Zulia, Venezuela / Mycoplasma genitalium detection and correlation with clinical manifestations in population of the Zulia State, Venezuela

Diverse studies demonstrate an association between Mycoplasma genitalium and urogenital pathologies. The aim of this study was to investigate the prevalence of M. genitalium in patients attending gynecological evaluation in private clinics (n = 172). DNA amplification assays of the genes 16S rRNA and MgPa were utilized. The prevalence of M. genitalium in the study population was 7.5 percent. M. genitalium was detected in 12.1 percent and 4.1 percent of the symptomatic and asymptomatic patients, respectively (p = 0.047). The infection was diagnosed in patients with cervicitis (17.2 percent) and mucopurulent secretion (16.6 percent) and the highest prevalence of infections was registered in the 31-40 years age group. No significant association between the presence of M.genitalium and individual clinical manifestations or the patients age was showed (p > 0.05). The high prevalence of M. genitalium infections, mostly in patients with clinical manifestations showed in this study, warrants the application of diagnostic strategies in the population to investigate the clinical meaning of these microorganisms and to reevaluate therapeutic schemes against non-gonococcal and non-chlamydial infections.

Diversos estudios demuestran una asociación entre Mycoplasma genitalium y patologías urogenitales. El objetivo de este trabajo fue investigar la prevalencia de infecciones por M. genitalium en pacientes atendidas en clínicas privadas (n = 172). Se utilizaron ensayos de amplificación de genes 16S rARN y MgPa. La prevalencia de M. genitalium en esta población fue 7,5 por ciento. Mycoplasma genitalium fue detectado en 12,1 y 4,1 por ciento) de las pacientes sintomáticas y asintomáticas, respectivamente (p = 0,047). La infección se diagnosticó en pacientes con cervicitis (17,2 por ciento) y con secreción mucopurulenta (16,6 por ciento) y la mayor prevalencia de infecciones se registró en el grupo etario de 31 a 40 años. No se encontró asociación significativa entre la presencia de M. genitalium y manifestaciones clínicas individuales o edad de las pacientes (p > 0,05). La alta prevalencia de infecciones por M. genitalium, principalmente en pacientes con manifestaciones clínicas demostrada en este estudio, demanda la aplicación de estrategias diagnósticas en la población para investigar el significado clínico de estos microorganismos y reevaluar esquemas terapéuticos contra infecciones no gonocóccicas y no clamidiales.

Tissue factor around dermal vessels has bound factor VII in the absence of injury.

BACKGROUND: 'Idling' or ongoing low-level activity of the tissue factor (TF) pathway is a postulated mechanism by which the coagulation process can become active without a lag period at sites of injury. OBJECTIVE: To determine whether TF around cutaneous vessels has bound factor VIIa in the absence of injury, and thus could participate in the idling process. METHODS: Immunostaining of mouse skin with antibodies against a 15-residue peptide from the sequence of mouse TF, and against the whole extracellular portion of TF. RESULTS: The whole TF antibody recognized TF in squamous epithelium and around vessels in the dermis. By contrast, the monospecific antibody only recognized TF in the squamous epithelium, but not around vessels. We also found that biotinylated, active site-inhibited FVIIa (FVIIai) bound to tissue sections in the same areas in which TF was recognized by the monospecific antibody (squamous epithelium), but did not bind around vessels. Molecular modeling revealed that FVIIa and FX binding to TF masked a significant part of the surface of the target peptide. CONCLUSIONS: In the aggregate, these data are most consistent with the interpretation that TF in perivascular sites has bound FVIIa, even in the absence of any injury. The presence of endogenously bound FVIIa prevents the subsequent binding of the monospecific antibody or exogenous FVIIai to perivascular TF.

Evaluation of the presence of a thapsigargin-sensitive calcium store in trypanosomatids using Trypanosoma evansi as a model.

Ca2+ plays an important role in the regulation of several important activities in different trypanosomatids. These parasites possess a Ca2+ transport system in the endoplasmic reticulum (ER) involved in Ca2+ homeostasis, which has been reported to be insensitive to thapsigargin, a classical inhibitor of the sarcoplasmic-ER Ca2+ adenosine triphosphatase (ATPase) (SERCA) in most eukaryotic cells. However, currently there is a controversy regarding the existence of a thapsigargin-sensitive ER Ca2+ store in these parasites. Therefore, we decided to explore the effect of this inhibitor using different methodological approaches. First, we selected Trypanosoma evansi as a parasite model to warrant the homogeneity of the population because this parasite has only a single life cycle, i.e., bloodstream-form trypomastigotes. Second, we compared the thapsigargin effect on Ca2+ homeostasis by spectrophotometrical Ca2+ measurements using 3 different approaches: whole-cell populations, cells that have been permeabilized by treatment with digitonin, and intact single cells. Our results demonstrate that a low concentration of thapsigargin induces Ca2+ release from intracellular Ca2+ stores in this parasite, which can be observed independently of the method used. Furthermore, the addition of thapsigargin before or after nigericin did not abolish its effect, showing that thapsigargin acts specifically on the ER. In conclusion, our results indicate the presence of a nonmitochondrial thapsigargin-sensitive Ca2+ store in T. evansi.

Numerical proposal for a semiological classification of clinical findings.

The principal goal of this paper is to present a numerical classification of the characteristics of symptoms and signs. This classification begins with the ICD9 code and takes into account the semiological aspects of the already mentioned symptoms an signs, in such a way, that a digit represents, in cases of abdominal pain, site, another: radiating to, and the followings: aggravating, relieving factors, progress, duration and type. This way of representing data, with only a digit for each characteristic facilitates registration and elaboration of data bases, as well as, electronic data interchange.