The colorful Helly theorem and general hypergraphs

AbstractThe definition of the Helly property for hypergraphs was motivated by the Helly theorem for convex sets. Similarly, we define the colorful Helly property for a family of hypergraphs, motivated by the colorful Helly theorem for collections of convex sets, by Lovász. We describe some general facts about the colorful Helly property and prove complexity results. In particular, we show that it is Co-NP-complete to decide if a family of p hypergraphs is colorful Helly, even if p=2. However, for any fixed p, we describe a polynomial time algorithm to decide if such family is colorful Helly, provided at least p−1 of the hypergraphs are p-Helly

Preparation of hybrid organic-inorganic materials based on a di-ureasil matrix doped with lithium bis(trifluoromethanesulfonyl)imide

In this presentation we describe the preparation of solvent-free solid polymer electrolytes (SPEs) by the sol-gel route with the incorporation of controlled quantities of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) into the host matrix. The host framework of these xerogels, designated as di-ureasils and represented by d-U(900), contains oxyethylene oligomers with about 15 repeat units bonded at each end to a siliceous backbone through urea bridging links. Electrolytes were characterized by ionic conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis. The results obtained reveal that these hybrid materials are completely amorphous and exhibit appropriate electrochemical characteristics for a variety of applications.Fundação para a Ciência e a Tecnologia - POCI/QUI/59856/2004; POCTI/3/686; SFRH/BD/22707/2005

Repeated nitrogen starvation doesn't affect lipid productivity of Chlorococcum littorale

Paid Open Acces

Cell diameter doesn't affect lipid productivity of Chlorococcum littorale

Paid Open Acces

Sorting cells of the microalga Chlorococcum littorale with increased triacylglycerol productivity

Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological variability of species to select variations based on desired characteristics. We focused on triacylglycerol (TAG), which have applications ranging from biodiesel to high-value omega-3 fatty-acids. Hence, we demonstrated a strategy to sort microalgae cells with increased TAG productivity

Gene trio signatures as molecular markers to predict response to doxorubicin cyclophosphamide neoadjuvant chemotherapy in breast cancerpatients

In breast cancer patients submitted to neoadjuvant chemotherapy (4 cycles of doxorubicin and cyclophosphamide, AC), expression of groups of three genes (gene trio signatures) could distinguish responsive from non-responsive tumors, as demonstrated by cDNA microarray profiling in a previous study by our group. In the current study, we determined if the expression of the same genes would retain the predictive strength, when analyzed by a more accessible technique (real-time RT-PCR). We evaluated 28 samples already analyzed by cDNA microarray, as a technical validation procedure, and 14 tumors, as an independent biological validation set. All patients received neoadjuvant chemotherapy (4 AC). Among five trio combinations previously identified, defined by nine genes individually investigated (BZRP, CLPTM1,MTSS1, NOTCH1, NUP210, PRSS11, RPL37A, SMYD2, and XLHSRF-1), the most accurate were established by RPL37A, XLHSRF-1based trios, with NOTCH1 or NUP210. Both trios correctly separated 86% of tumors (87% sensitivity and 80% specificity for predicting response), according to their response to chemotherapy (82% in a leave-one-out cross-validation method). Using the pre-established features obtained by linear discriminant analysis, 71% samples from the biological validation set were also correctly classified by both trios (72% sensitivity; 66% specificity). Furthermore, we explored other gene combinations to achieve a higher accuracy in the technical validation group (as a training set). A new trio, MTSS1, RPL37 and SMYD2, correctly classified 93% of samples from the technical validation group (95% sensitivity and 80% specificity; 86% accuracy by the cross-validation method) and 79% from the biological validation group (72% sensitivity and 100% specificity). Therefore, the combined expression of MTSS1, RPL37 and SMYD2, as evaluated by real-time RT-PCR, is a potential candidate to predict response to neoadjuvant doxorubicin and cyclophosphamide in breast cancer patients

Desigualdades regionais na mortalidade por câncer de colo de útero no Brasil: tendências e projeções até o ano 2030

O objetivo deste artigo é analisar a tendência temporal da mortalidade por câncer de colo de útero no Brasil e calcular uma projeção até o ano de 2030. Foram analisados os óbitos ocorridos no Brasil de 1996 a 2010 (Sistema de Informações sobre Mortalidade). Foram realizadas análises das tendências da mortalidade por meio da regressão Joinpoint, e para o cálculo das projeções foi utilizado o Nordpred. Para o Brasil, a tendência é de redução (APC = 1, 7% IC95%-2, 2; -1, 1 p < 0, 05), sendo significativa nas regiões centro oeste (APC = -1, 3% ao ano), sudeste (APC =-3, 3%) e sul (APC = -3, 9%). As regiões norte e nordeste apresntam tendência de estabilidade. Os estados do Acre (APC = -6, 5%) e Rio Grande do Sul (APC = -4, 1%) apresentaram as maiores tendências de redução. Na análise das projeções de mortalidade, haverá uma redução das taxas no Brasil a partir do primeiro período projetado, sendo mais marcante para a região sul. As taxas de mortalidade até o ano 2030 serão explicadas, em maior medida, pela redução dos risco para a doença. A mortalidade por câncer de colo de útero apresenta tendência de redução, todavia está desigualmente distribuída no Brasil, com as regiões norte e nordeste apresentando as maiores taxas. The scope of this article is to analyze the temporal trends of cervical cancer mortality in Brazil and calculate the projection of mortality through to the year 2030. Deaths that occurred within the 1996-2010 period were analyzed (Mortality Information System). Mortality trend analysis utilized the Joinpoint regression, while Nordpred was utilized for the calculation of projections. For Brazil, decreasing trends were identified (APC = 1.7% CI95%-2.2; -1.1 p < 0.05). The Midwest region presented a significant reduction trend (APC = -1.3% per year), along with the Southeast (APC = -3.3%) and South (APC = -3.9%) regions. The North and Northeast regions presented stable trends. The states of Acre (APC = -6.5%) and Rio Grande do Sul (APC = -4.1%) presented the most pronounced reduction trends. Analysis of the mortality projections revealed a reduction in mortality rates, starting from the first projected period, with a considerable reduction for the South region. Mortality rates through to the year 2030 are explained, principally, by reductions in the riskof the disease. Cervical cancer mortality presents reducing trends, however these are unequally distributed throughout the country, where the North and Northeast regions present the highest mortality rates

Mechanical Properties Of Stored Red Blood Cells Using Optical Tweezers

We have developed a method for measuring the red blood cell (RBC) membrane overall elasticity μ by measuring the deformation of the cells when dragged at a constant velocity through a plasma fluid by an optical tweezers. The deformability of erythrocytes is a critical determinant of blood flow in the microcirculation. We tested our method and hydrodynamic models, which included the presence of two walls, by measuring the RBC deformation as a function of drag velocity and of the distance to the walls. The capability and sensitivity of this method can be evaluated by its application to a variety of studies, such as, the measurement of RBC elasticity of sickle cell anemia patients comparing homozygous (HbSS), including patients taking hydroxyrea (HU) and heterozygous (HbAS) with normal donors and the RBC elasticity measurement of gamma irradiated stored blood for transfusion to immunosupressed patients as a function of time and dose. These studies show that the technique has the sensitivity to discriminate heterozygous and homozygous sickle cell anemia patients from normal donors and even follow the course of HU treatment of Homozygous patients. The gamma irradiation studies show that there is no significant change in RBC elasticity over time for up to 14 days of storage, regardless of whether the unit was irradiated or not, but there was a huge change in the measured elasticity for the RBC units stored for more than 21 days after irradiation. These finds are important for the assessment of stored irradiated RBC viability for transfusion purposes because the present protocol consider 28 storage days after irradiation as the limit for the RBC usage.593016Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Barjas-Castro, M.L., Brandão, M.M., Fontes, A., Costa, F.F., Cesar, C.L., Saad, S.T.O., Elastic properties of irradiated red blood cell units measured by optical tweezer (2002) Transfusion, 42, pp. 1196-1199Brandão, M.M., Fontes, A., Barjas-Castro, M.L., Barbosa, L.C., Costa, F.F., Cesar, C.L., Saad, S.T.O., Optical tweezers for measuring red blood cell elasticity: Application to the study of drug response in sickle cell disease (2003) European Journal of Haematology, 70, pp. 207-211Williamson, L.M., Warwick, R.M., Transfusion-associated graft-versus-host disease and its prevention (1995) Blood Rev., 9, pp. 251-261Button, L.N., Dewolf, W.C., Newburger, P.E., The effecr of irradiation on blood components (1981) Transfusion, 21, pp. 419-426Platt, O.S., The sickle syndrome (1995) Blood: Principles and Practice of Hematology, , R. I Hadlin, S. E. Lux, T. P. Stossel, J. B. Lippincott, PhiladelphiaBallas, S.K., Dover, G.J., Charache, S., Effect of hydroxyurea on the rheological properties of sickle erythrocytes in vivo (1989) Am. J. Hematol, 32, pp. 104-111Groner, W., Mohandas, N., Bessis, M., New optical technique for measuring erythrocyte deformability with the ektacytometer (1980) Clin. Chem., 26, pp. 1435-1442De Franceschi, L., Bachir, D., Galacteros, F., Tchernia, G., Cynober, T., Alper, S., Platt, O., Brugnara, C., Oral magnesium supplements reduce erythrocyte dehydration in patients with sickle cell disease (1997) J Clin Invest, 100, pp. 1847-1852Hochmuth, R.M., Worthy, P.R., Evans, E.A., Red cell extensional recovery and the determination of membrane viscosity (1979) Biophys. J., 26, pp. 101-114Evans, E.A., La Celle, P.L., Intrinsic material properties of the erythrocyte membrane indicated by mechanical analysis of deformation (1975) Blood, 45, pp. 29-43Itoh, T., Chien, S., Usami, S., Effects of hemoglobin concentration on deformability of individual sickle cells after deoxygenation (1995) Blood, 85, pp. 2245-2253Evans, E.A., Mohandas, N., Membrane-associated sickle hemoglobin: A major determinant of sickle erythrocyte rigidity (1987) Blood, 70, pp. 1443-1449Dong, C., Chadwick, R.S., Schechter, A.N., Influence of sickle hemoglobin polymerization and membrane properties on deformability of sickle erythrocytes in the microcirculation (1992) Biophys. J., 63, pp. 774-783Suzuki, Y., Tateishi, N., Cicha, I., Decreased deformability of the X-ray irradiated red blood cells stored in manitol-adenine-phosphate medium (2000) Clin. Hemorheol. Micro-cire., 22, pp. 131-14