R. B. SCIURANO, M.S. MERANI, JIMENA BUSTOS, A.J. SOLARI

BIOCELL, Vol.30, No.1, pp. 57-66, 2006, DOI:10.32604/biocell.2006.30.057

Abstract Spermatocytes from the two armadillo species, C. villosus and D. hybridus were studied in microspreads for synaptonemal complexes (SCs) and in thin sections for electron microscopy (EM). The complete SC karyotype generally agrees with previous reports on mitotic chromosomes, except for the sex chromosomes. The X chromosome is submetacentric in both species and the Y is the shortest one in C. villosus and the second shortest in D. hybridus, and an extremely acrocentric one. A SC is formed along the total length of the Y chromosome, and this SC persists along all the pachytene substages. A single recombination nodule… More >

ZONG-YUN LI^1,2*, MEI-LI FU¹, FANG-FANG HU¹, SHU-FENG HUANG¹, YUN-CHUN SONG²

BIOCELL, Vol.30, No.1, pp. 27-32, 2006, DOI:10.32604/biocell.2006.30.027

Abstract The ribosomal DNA (45S rDNA) behaviors during the cell cycle were analyzed on interphase nuclei, prophases, metaphases, pachytene chromosomes and extended DNA fibers in rice (Oryza,sativa ssp.indica cv.Guangluai No.4) by using high-resolution fluorescent in situ hybridization (FISH). The results show that 45S rDNA is located at the ends of short arms of chromosomes 9 and 10. But the signals are much more intense on chromosome 9 than on chromosome 10 in metaphase. Pachytene chromosome has rDNA signal arrays on chromosome 9. Different phases are described and discussed. These results indicate that the activity of rDNA at individual More >

F. X. Hart¹

Molecular & Cellular Biomechanics, Vol.3, No.4, pp. 235-235, 2006, DOI:10.32604/mcb.2006.003.235

Abstract This article has no abstract. More >

H. Nakagawa¹, T. Shiina², M. Kotani³, H. Kotani¹, S. Ueno¹

Molecular & Cellular Biomechanics, Vol.3, No.4, pp. 163-163, 2006, DOI:10.32604/mcb.2006.003.163

Abstract This article has no abstract. More >

S. Marguet¹, P. Rozycki¹, L. Gornet¹

CMC-Computers, Materials & Continua, Vol.4, No.3, pp. 119-136, 2006, DOI:10.3970/cmc.2006.004.119

Abstract This paper deals with the modelling until rupture of composite structures made of glass-fibre / epoxy-resin woven fabrics submitted to dynamic loadings. The model is built at the mesoscale of the elementary ply. It takes into account the slightly nonlinear brittle behaviour of the fibres under tensile sollicitations, their nonlinear behaviour in compression as well as the strongly non linear and irreversible behaviour of the ply in shear. Strain rate effects are also introduced and special attention is paid to the objectivity of the model in the context of finite element calculation. Therefore the choice… More >

KARINA SAYURI UTSUNOMIYA*, MARIA SUELY PAGLIARINI*, CACILDA BORGES DO VALLE**

BIOCELL, Vol.29, No.3, pp. 295-301, 2005, DOI:10.32604/biocell.2005.29.295

Abstract The genus Brachiaria (Trin.) Griseb. has achieved considerable importance to cattle production systems, as a result of the good production and adaptation of a few cultivars to poor and acid soils of the Brazilian savannas. Many of its species and accessions are polyploid and apomictic, which limits direct hybridization. To assist the breeding program, cytogenetic characterization has been undertaken on the accessions of Brachiaria collection at the Embrapa Beef Cattle Research Center. In this study, chromosome number and meiotic behavior are reported for the Brachiaria nigropedata (Ficalho & Hiern) Stapf collection. The 20 available accessions are tetraploid… More >

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 >