1,202 research outputs found

    Models with commutative orthogonal block structure: a general condition for commutativity

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    This work was partially supported by national founds of FCT-Foundation for Science and Technology under UID/MAT/00297/2019 and UID/MAT/00212/2019.A linear mixed model whose variance-covariance matrix is a linear combination of known pairwise orthogonal projection matrices that add to the identity matrix, is a model with orthogonal block structure (OBS). OBS have estimators with good behavior for estimable vectors and variance components, moreover it may be interesting that the least squares estimators give the best linear unbiased estimators, for estimable vectors. We can achieve it, requiring commutativity between the orthogonal projection matrix, on the space spanned by the mean vector, and the orthogonal projection matrices involved in the expression of the variance-covariance matrix. This commutativity condition defines a more restrict class of OBS, named COBS (model with commutative orthogonal block structure). With this work we aim to present a commutativity condition, resorting to a special class of matrices, named U-matrices.publishersversioninpres

    Taming combinatorial explosion of the formose reaction via recursion within mineral environments

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    One‐pot reactions of simple precursors, such as those found in the formose reaction or formamide condensation, continuously lead to combinatorial explosions in which simple building blocks capable of function exist, but are in insufficient concentration to self‐organize, adapt, and thus generate complexity. We set out to explore the effect of recursion on such complex mixtures by ‘seeding’ the product mixture into a fresh version of the reaction, with the inclusion of different mineral environments, over a number of reaction cycles. Through untargeted UPLC‐HRMS analysis of the mixtures we found that the overall number of products detected reduces as the number of cycles increases, as a result of recursively enhanced mineral environment selectivity, thus limiting the combinatorial explosion. This discovery demonstrates how the involvement of mineral surfaces with simple reactions could lead to the emergence of some building blocks found in RNA, Ribose and Uracil, under much simpler conditions that originally thought

    Tracer diffusion in granular shear flows

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    Tracer diffusion in a granular gas in simple shear flow is analyzed. The analysis is made from a perturbation solution of the Boltzmann kinetic equation through first order in the gradient of the mole fraction of tracer particles. The reference state (zeroth-order approximation) corresponds to a Sonine solution of the Boltzmann equation, which holds for arbitrary values of the restitution coefficients. Due to the anisotropy induced in the system by the shear flow, the mass flux defines a diffusion tensor DijD_{ij} instead of a scalar diffusion coefficient. The elements of this tensor are given in terms of the restitution coefficients and mass and size ratios. The dependence of the diffusion tensor on the parameters of the problem is illustrated in the three-dimensional case. The results show that the influence of dissipation on the elements DijD_{ij} is in general quite important, even for moderate values of the restitution coefficients. In the case of self-diffusion (mechanically equivalent particles), the trends observed in recent molecular dynamics simulations are similar to those obtained here from the Boltzmann kinetic theory.Comment: 5 figure

    Experiências de cataforese com suspensões da fracção argilosa do solo

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    Camperdown Hemoglobin Associated With β° Thalassemia In A Brazilian Child

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    We report the coexistence of Hb Camperdown [β 104 (G6) Arg → Ser] and β°-thalassemia [β39 (Gln → stop codon)] in a nine-month-old Brazilian boy. He had a relatively more severe hypochromic and microcytic anemia in comparison to his mother's β-thalassemia trait. His Hb Camperdown heterozygous father was clinically and hematologically normal. To our knowledge, this is the first description of an association of β°-thalassemia with Hb Camperdown. Copyright by the Brazilian Society of Genetics.283394396Araújo, A.S., Silva, W.A., Leao, S.A., Bandeira, F.C., Petrou, M., Modell, B., Zago, M.A., A different molecular pattern of β-thalassemia mutations in Northeast of Brazil (2003) Hemoglobin, 27, pp. 211-217Amone, A., X-ray diffraction study of binding of 2,3-diphosphoglycerate to human deoxyhemoglobin (1972) Nature, 237, pp. 146-149Bertuzzo, C.S., Sonati, M.F., Costa, F.F., Hematological phenotype and the type of β thalassemia mutation in Brazil (1997) Braz J Genet, 20, pp. 319-321Bianco, I., Graziani, B., Carboni, C., Genetic patterns in thalassemia intermedia (constitutional microcytic anemia). Familial hematological and biosynthetic studies (1977) Hum Hered, 27, pp. 257-272Blouquit, Y., Lacombe, C., Arous, N., Le Qurrec, A., Branconnier, F., Bonhomme, J., Soummer, A.M., Galacteros, F., Seven new cases of hemoglobin Camperdown alpha 2 beta 2 104 (G6) ARG → SER found in Malta, Sicily and Tunisia (1984) Hemoglobin, 8, pp. 613-619Chang, J.C., Kan, Y.W., β°-thalassemia, a nonsense mutation in man (1979) Proc Natl Acad Sci USA, 76, pp. 2886-2889Clarke, G.M., Higgins, T.N., Laboratory investigation of hemoglobinopathies and thalassemias: Review and update (2000) Clin Chem, 46, pp. 1284-1290Fonseca, S.F., Kerbauy, J., Escrivçao, C., Figueiredo, M.S., Cançado, R., Arruda, V.R., Saad, S.T.O., Costa, F.F., Genetic analysis of beta-thalassemia major and beta-thalassemia intermedia in Brazil (1998) Hemoglobin, 22, pp. 197-207Grignoli, C.R.E., Carvalho, M.H., Kimura, E.M., Sonati, M.F., Arruda, V.R., Saad, S.T.O., Costa, F.F., β°-thalassemia resulting from a novel mutation: β66/u → stop codon (2000) Eur J Haematol, 64, pp. 137-138Kimura, E.M., Grignoli, C.R.E., Pinheiro, V.R.P., Costa, F.F., Sonati, M.F., Thalassemia intermedia as a result of heterozygosis for β°-thallassemia and αααanti3.7/αα genotype in a Brazilian patient (2003) Braz J Med Biol Res, 36, pp. 699-701Kister, J., Barbadjian, J., Blouquit, Y., Bohn, B., Galacteros, F., Poyart, C., Inhibition of oxygen-linked anion binding in Hb Camperdown [α2β2 104 (G6) ARG → SER] (1989) Hemoglobin, 13, pp. 567-578Miranda, S.R.P., Kimura, E.M., Teixeira, R.C., Bertuzzo, C.S., Ramalho, A.A., Saad, S.T.O., Costa, F.F., Hb Camperdown [α2β2 104 (G6) ARG → SER] identified by DNA analysis in a Brazilian family (1996) Hemoglobin, 20, pp. 147-153Old, J.M., Screening arid genetic diagnosis of haemoglobin disorders (2003) Blood Rev, 17, pp. 43-53Olivieri, N.F., The β-thalassemias (1999) N Engl J Med, 341, pp. 99-109Thein, S.L., Genetic insights into the clinical diversity of beta thalassaemia (2004) Br J Haematol, 124, pp. 264-274Weatherall, D.J., Clegg, J.B., Inherited haemoglobin disorders: An increasing global health problem (2001) Bull World Health Organ, 79, pp. 704-712Wilkinson, T., Chua, C.G., Carrell, R.W., Robin, H., Exner, T., Lee, K.M., Kronenberg, H., Haemoglobin Camperdown β 104(G6) Arginine leads to serine (1975) Biochim Biophys Acta, 393, pp. 195-200Zago, M.A., Costa, F.F., Hereditary hemoglobin disorders in Brazil (1985) Trans R Soc Trop Med Hyg, 79, pp. 385-38

    Efficient adeno-associated virus serotype 5 capture with affinity functionalized nanofiber adsorbents

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    Funding Information: The authors acknowledge the funding of Fundação para a Ciência e Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES, Portugal) through national funds to iNOVA4Health (UIDB/04462/2020 and UIDP/04462/2020), projects PTDC/EQU-EQU/0142/2020 and EXPL/EQU-EQU/1567/2021; SN is the recipient of an FCT fellowship from the project PTDC/EQU-EQU/0142/2020. Publisher Copyright: Copyright © 2023 Neto, Mendes, Santos, Solbrand, Carrondo, Peixoto and Silva.Adeno-associated viruses (AAVs) are one of the most promising tools for gene therapy applications. These vectors are purified using affinity and ion exchange chromatography, typically using packed beds of resin adsorbents. This leads to diffusion and pressure drop limitations that affect process productivity. Due to their high surface area and porosity, electrospun nanofiber adsorbents offer mass transfer and flow rate advantages over conventional chromatographic media. The present work investigated the use of affinity cellulose-based nanofiber adsorbents for adeno-associated virus serotype 5 (AAV5) capture, evaluating dynamic binding capacity, pressure drop, and AAV5 recovery at residence times (RT) less than 5 s. The dynamic binding capacity was found to be residence time-dependent, but nevertheless higher than 1.0 × 1014 TP mL−1 (RT = 1.6 s), with a pressure drop variation of 0.14 MPa obtained after loading more than 2,000 column volumes of clarified AAV5 feedstock. The single affinity chromatography purification step using these new affinity adsorbents resulted in 80% virus recovery, with the removal of impurities comparable to that of bead-based affinity adsorbents. The high binding capacity, virus recovery and reduced pressure drop observed at residence times in the sub-minute range can potentially eliminate the need for prior concentration steps, thereby reducing the overall number of unit operations, process time and costs.publishersversionpublishe

    Gallium-67 Imaging In A Patient With Paracoccidioidomycosis: A Case Report

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    A 26 year-old female was admitted with abdominal pain, fever and weight loss. The clinical and laboratory investigations led to the diagnosis of paracoccidioidomycosis. Gallium-67 whole body images correlated well with the clinical course of the disease and with the patient's prognosis.423167170Barbosa, W., Paracoccidioidomicose (Blastomicose sul-americana) (1989), pp. 653-662. , AMATO NETO, V. & BALDY, J.L.S., ed. Doenças transmissíveis. 3. ed. São Paulo, SarvierBarbosa, W., Daher, R.R., Blastomicose sul-americana (Paracoccidioidomicose) (1995), pp. 634-646. , VERONESI, R.FOCACCIA, R. & DIETZE, R., ed. Doenças infecciosas e parasitárias. 8. ed. São Paulo, Guanabara-KooganBecker, W., The contribution of nuclear medicine to the patient with infection (1995) Europ. J. Nucl. Med., 22, pp. 1195-1211Bethlem, N.M., Lemle, A., Bethlem, E., Wanke, B., Paracoccidioidomycosis (1991) Semin. Resp. Med., 12, pp. 81-97Braga, F.J.H.N., Abreu, P.R., Rivitti, M.C.M., La paracoccidioidomycose chéloide étudiée avec le gallium (1992) Bull. Soc. Path. Exot., 85, pp. 118-119Braga, F.J.H.N., Camargo, E.E., Segurado, A.A.C., La paracoccidioidomycose évaluée par quatre études isotopiques (1992) Bull. Soc. Path. Exot., 85, pp. 115-117Dayaniki, B.F., Weissman, A.F., Wahl, R.L., Successful gallium-67 imaging of North American pulmonary blastomycosis (1993) J. Nucl. Med., 34, pp. 958-960Del Negro, G.M.B., Garcia, N.M., Rodrigues, E.G., The sensitivity, specificity and efficiency values of some serological tests used in the diagnosis of paracoccidioidomycosis (1991) Rev. Inst. Med. Trop. S. Paulo, 33, pp. 277-280Giorgi, M.C.P., Camargo, E.E., Pinto, W.P., Del Negro, G., Gallium-67 imaging in the diagnosis of blastomycosis (1987) Europ. J. Nucl. Med., 13, pp. 300-304Negroni, R., Paracoccidioidomycosis (1993) Int. J. Derm., 32, pp. 847-859Palestro, C.J., The current role of gallium imaging in infection (1994) Semin. Nucl. Med., 24, pp. 128-141Peters, A.M., The use of nuclear medicine in infections (1998) Brit. J. Radiol., 71, pp. 252-26

    Amplification of evanescent waves in a lossy left-handed material slab

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    We carry out finite-difference time-domain (FDTD) simulations, with a specially-designed boundary condition, on pure evanescent waves interacting with a lossy left-handed material (LHM) slab. Our results provide the first full-wave numerical evidence for the amplification of evanescent waves inside a LHM slab of finite absorption. The amplification is due to the interactions between the evanescent waves and the coupled surface polaritons at the two surfaces of the LHM slab and the physical process can be described by a simple model.Comment: 4 pages, 2 figure

    A continuous source of translationally cold dipolar molecules

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    The Stark interaction of polar molecules with an inhomogeneous electric field is exploited to select slow molecules from a room-temperature reservoir and guide them into an ultrahigh vacuum chamber. A linear electrostatic quadrupole with a curved section selects molecules with small transverse and longitudinal velocities. The source is tested with formaldehyde (H2CO) and deuterated ammonia (ND3). With H2CO a continuous flux is measured of approximately 10^9/s and a longitudinal temperature of a few K. The data are compared with the result of a Monte Carlo simulation.Comment: 4 pages, 4 figures v2: small changes in the abstract, text and references. Figures 1 & 2 regenerated to prevent errors in the pd
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