M.I. PIGOZZI, R.B. SCIURANO, A.J. SOLARI

BIOCELL, Vol.29, No.2, pp. 195-203, 2005, DOI:10.32604/biocell.2005.29.195

Abstract A testicular biopsy from an infertile man carrying a heterozygous chromosome translocation t(11;14) was studied with synaptonemal complex analysis and immunolocalization of the protein MLH1 for crossover detection. A full blockage of spermatogenesis at the spermatocyte stage was related to the presence of the translocation quadrivalents at pachytene. Only 2% of the quadrivalents showed full synapsis. Most of the spermatocytes showed asynaptic free ends that frequently mingled with the XY pair. The average number of crossovers per cell was diminished from a mean of 52.7 in controls to a mean of 48 in the patient. More >

NILTON CESAR PIRES BIONE¹, MARIA SUELY PAGLIARINI², LEONES ALVES DE ALMEIDA³

BIOCELL, Vol.29, No.2, pp. 177-181, 2005, DOI:10.32604/biocell.2005.29.177

Abstract A spontaneous male-sterile, female-fertile mutation affecting bivalent arrangement at the metaphase plate and cytokinesis was detected in line BR98-197 of the soybean breeding program developed by Embrapa – National Soybean Research Centre. Untill diakinesis, meiosis was normal with chromosome pairing as bivalents. From this phase, in several meiocytes, bivalents were not able to organize a single metaphase plate and remained scattered in the cytoplasm in a few or several groups. In these meiocytes, chromosomes segregated in both divisions giving rise to several micronuclei. However, the main cause of male sterility was the absence of cytokinesis More >

Gustav Amberg¹, Junichiro Shiomi²

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.1, pp. 81-96, 2005, DOI:10.3970/fdmp.2005.001.081

Abstract A few issues in materials science are reviewed with regard to the importance of fluid flows. The effect of convection on generic solidification problems is discussed. One relevant class of flows in melts is those driven by surface tension gradients. In welding this thermo- or solutocapillary flow will determine the penetration depth, and will depend very sensitively on the composition of the material, through the dependence of surface tension on temperature, presence of surfactants, etc. In crystal growth the convective motion in the melt may cause instabilities that are often undesired in practical processes. The More >

M. I. ROSATTI, M. T. BECONI, M. CÓRDOBA

BIOCELL, Vol.28, No.3, pp. 311-316, 2004, DOI:10.32604/biocell.2004.28.311

Abstract Acrosin activity is associated with normal fertility in human and bovine spermatozoa. The aim of the study was to determine the variation of the enzyme activity in the proacrosin-acrosin system in capacitated and acrosome reacted cryopreserved bovine sperm. Enzyme activity was assessed spectrophotometrically using N-α-benzoyl-DL-arginine p-nitroanilide (BAPNA) as specific substrate for acrosin at pH 8. Capacitation with heparin and quercitin failed to induce conversion of proacrosin to acrosin. An increase in acrosin activity produced by the presence of progesterone, in a dose-dependent manner, was related with the induction of true acrosome reaction. The total level More >

MARÍA ESTHER DIUPOTEX-CHONG¹, NÉSTOR J. CAZZANIGA², ALEJANDRA HERNÁNDEZ-SANTOYO³, JOSÉ MIGUEL BETANCOURT-RULE⁴

BIOCELL, Vol.28, No.3, pp. 279-285, 2004, DOI:10.32604/biocell.2004.28.279

Abstract Mitotic chromosomes of the freshwater snail Pomacea patula catemacensis (Baker 1922) were analyzed on gill tissue of specimens from the type locality (Lake Catemaco, Mexico). The diploid number of chromosomes is 2n = 26, including nine metacentric and four submetacentric pairs; therefore, the fundamental number is FN = 52. No sex chromosomes could be identified. The same chromosome number and morphology were already reported for P. flagellata, i.e., the other species of the genus living in Mexico. The basic haploid number for family Ampullariidae was reported to be n° =°14 in the literature; so, its reduction to More >

B. Amaziane¹, A. Naji², D. Ouazar³

CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 117-128, 2004, DOI:10.3970/cmc.2004.001.117

Abstract In this paper, a meshless method based on Radial Basis Functions (RBF) is coupled with genetic algorithms for parameter identification to some selected groundwater flow applications. The treated examples are generated by the diffusion equation with some specific boundary conditions describing the groundwater fluctuation in a leaky confined aquifer system near open tidal water. To select the best radial function interpolation and show the powerful of the method in comparison to domain based discretization methods, Multiquadric (MQ), Thin-Plate Spline (TPS) and Conical type functions are investigated and compared to finite difference results or analytical one. More >

Yiorgos-Sokratis Smyrlis¹, Andreas Karageorghis¹

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 535-550, 2003, DOI:10.3970/cmes.2003.004.535

Abstract In this study, we investigate the application of the Method of Fundamental Solutions for the solution of biharmonic Dirichlet problems on a disk. Modifications of the method for overcoming sources of inaccuracy are suggested. We also propose an efficient algorithm for the solution of the resulting systems which exploits the symmetries of the matrices involved. The techniques described in the paper are applied to standard test problems. More >

CHARLES GÉMINARD, AUDE DE GASSART, MICHEL VIDAL

BIOCELL, Vol.26, No.2, pp. 205-215, 2002, DOI:10.32604/biocell.2002.26.205

Abstract During the differentiation of erythroid cells, a vast program of maturation takes place, leading to decay or elimination of organelles, including the nucleus, mitochondria, ribosomes, lysosomes, endoplasmic reticulum and Golgi apparatus. During the last step of red cell maturation, remaining organelles, primarily mitochondria and ribosomes but also vestiges of others are finally cleared from the cell. This cleaning session also affects specific proteins that are partially or entirely removed from the cell surface. The interplay of the various events and their causal relationships are approached here. More >