Universidade de Pernambuco

About: Universidade de Pernambuco is a education organization based out in Recife, Brazil. It is known for research contribution in the topics: Population & Medicine. The organization has 6147 authors who have published 6948 publications receiving 73648 citations.

Variable-Structure Generalized Delayed Signal Cancellation PLL to Improve Convergence Time

Abstract: This paper shows a scheme for improving the detection performance of the fundamental-frequency positive-sequence (FFPS) space vector through the generalized delayed signal cancellation phase-locked loop (GDSC-PLL) We implemented a variable-structure scheme in order to reduce the convergence time by changing the traditional datapath whenever even harmonics are not present in the input signal If this condition is not true, the performances of the variable-structure GDSC-PLL and the traditional GDSC-PLL for detecting the FFPS space vector will be similar Therefore, the variable-structure GDSC-PLL does not require a previous knowledge about the harmonic components of the three-phase signal Furthermore, we improved the frequency-adaptive scheme The performances of the original and proposed schemes were compared through transient test cases based on IEC 61000 and typical electrical events The new approach led to a reduction of up to 62% in the convergence time

Physical exercise and blood pressure control

Abstract: Physical exercise causes a series of physiological responses resulting from autonomic and hemodynamic adaptation that affect the cardiovascular system. Many studies have demonstrated its beneficial effect on blood pressure. Bearing in mind that hypertension is a very prevalent condition causing high morbidity and mortality rate, the physical exercise plays an important role as a nondrug measure for its control or as an adjuvant to drug treatment.

Meningococcal conjugate vaccines: efficacy and new combinations

Abstract: Meningococcal disease continues to be a serious public health concern being associated with high morbidity and mortality rates worldwide particularly in Brazil. In addition to discussing recent changes in the global epidemiology of meningococcal disease we also analyze the development and impact of new conjugate vaccines on the prevention of meningococcal disease with emphasis on the different immunization strategies implemented with these vaccines. MEDLINE databases were searched from 1996 to 2006 with emphasis on review articles clinical trials and epidemiological studies. Information was also sought on the Centers for Disease Control and Prevention Brazilian Ministry of Health and Sao Paulo state Epidemiological Surveillance Center websites. Five serogroups (A B C W135 and Y) are responsible for virtually all cases of the disease worldwide with marked regional and temporal differences. The new meningococcal serogroup C conjugate vaccines (MCC) offer unmistakable advantages over polysaccharide vaccines. MCC vaccines generate a more efficient and long-lasting antibody response inducing immunologic memory and reduction of nasopharyngeal carriage. The immediate results of introducing these vaccines into immunization programs have been encouraging with a dramatic reduction in the incidence of serogroup C disease not only in vaccinated but also in unvaccinated individuals (herd immunity). However concerns have arisen regarding the long term effectiveness of these vaccines especially for infants vaccinated in the routine schedule. The reported waning of efficacy more than 1 year after routine infant immunization supports alternative schedules incorporating a booster dose of MCC vaccine given at 12-18 months of age in order to maintain long-term protection. The recent licensure of the tetravalent meningococcal conjugate vaccine represents at last a real possibility of a broader protection against meningococcal disease although the need to develop an effective vaccine against serogroup B remains. (authors)

Gold electrode modified by self-assembled monolayers of thiols to determine DNA sequences hybridization

Abstract: The process of immobilization of biological molecules is one of the most important steps in the construction of a biosensor. In the case of DNA, the way it exposes its bases can result in electrochemical signals to acceptable levels. The use of self-assembled monolayer that allows a connection to the gold thiol group and DNA binding to an aldehydic ligand resulted in the possibility of determining DNA hybridization. Immobilized single strand of DNA (ssDNA) from calf thymus pre-formed from alkanethiol film was formed by incubating a solution of 2-aminoethanothiol (Cys) followed by glutaraldehyde (Glu). Cyclic voltammetry (CV) was used to characterize the self-assembled monolayer on the gold electrode and, also, to study the immobilization of ssDNA probe and hybridization with the complementary sequence (target ssDNA). The ssDNA probe presents a well-defined oxidation peak at +0.158 V. When the hybridization occurs, this peak disappears which confirms the efficacy of the annealing and the DNA double helix performing without the presence of electroactive indicators. The use of SAM resulted in a stable immobilization of the ssDNA probe, enabling the hybridization detection without labels. This study represents a promising approach for molecular biosensor with sensible and reproducible results.