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Pattern II (pattern + ii)

Distribution by Scientific Domains

Life Sciences	25%

Selected Abstracts

Identifying patterns of diversity of the actinopterygian fulcra

ACTA ZOOLOGICA, Issue 2009
Gloria Arratia
Abstract Fin rays, scutes or ridge scales, and fulcra have been traditionally interpreted as modified scales, but their diversity has been almost ignored. Based on results presented here, revised definitions of these elements are provided. At least two patterns of basal fulcra are found in actinopterygians: in Pattern I all or most basal fulcra are paired elements, whereas in Pattern II, a series of unpaired basal fulcra that are bifurcated proximally, and whose forking gradually becomes larger caudad, are followed by a series of paired elements. Basal fulcra are commonly present on unpaired fins of lower actinopterygians, including basal neopterygians. Among living fish they are absent in polypteriforms, Amia and teleosts. Fringing fulcra are always paired. Three patterns of fringing fulcra series are described: the series of fringing fulcra in basal actinopterygians is formed by expanded terminal segments of marginal lepidotrichia (Pattern A). Another series is formed by a combination of slightly expanded or modified terminal segments of rays and independent spiny, small elements (Pattern B). The third series is formed of small, spiny ossified elements positioned along the leading marginal fin ray(s) (Pattern C). Other patterns of basal and fringing fulcra remain to be investigated, along with their phylogenetic implications. [source]

Equal strain consolidation for stone columns reinforced foundation

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 15 2009
Kang-He Xie
Abstract Column consolidation and deformation are considered by assuming that the quantity of water flowing through the disturbed soil zone into the column is not equal to that flowing out from the column and the difference between them is equal to the volume change of the column. In addition, three patterns of distribution of the horizontal permeability of soil in the disturbed zone are also considered to account for the disturbance effect of columns construction on the surrounding soil. These three patterns include the constant distribution pattern (Pattern I), the linear distribution pattern (Pattern II) and the parabolic distribution pattern (Pattern III). By incorporating the aforementioned characteristics into the analyses, the governing equations containing two variables (i.e. the average excess pore-water pressures within the column and within the entire foundation at any depth) for the consolidation of a composite foundation are derived. The solutions of the governing equations are then obtained using a new initial condition derived from the assumption of equal strain and the equilibrium condition. On the basis of the solutions for excess pore-water pressures, the average degree of consolidation of a composite foundation is obtained and discussed. Finally, a comparison is made of some available solutions. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Patterns of the circumflex femoral arteries revisited

CLINICAL ANATOMY, Issue 2 2007
M.T. Vazquez
Abstract Knowledge of variations of the circumflex femoral arteries is important when undertaking clinical procedures within the femoral region and in hip joint replacement. Since the 19th century, many different patterns have been proposed to classify their origins. This work studied a statistically reliable sample, the lower limbs of 221 embalmed human cadavers (equal right,left and approximately equal sex distributions), and reviewed the previous literature to propose a unified and simple classification that will be useful to clinicians. Statistical comparisons were made using the ,2 test. The medial and lateral circumflex femoral arteries have been classified into three different patterns based on the levels of their origin. Distribution related to sex and side was also studied. Pattern I: Both arteries arose from the deep femoral artery (346 cases, 78.8%). This pattern was more frequent in females, P = 0.01. There was no significant difference between sides. Type Ia, medial circumflex femoral artery origin was proximal to the lateral circumflex femoral artery origin (53.2%); Type Ib, lateral circumflex femoral artery origin was proximal to medial circumflex femoral artery origin (23.4%); Type Ic, both arteries arose from a common trunk (23.4%). Pattern II: One of the arteries arose from the femoral artery and the other from the deep femoral artery (90 cases, 20.5%). Type IIa, the medial circumflex femoral artery arose from the femoral artery (77.8%) and Type IIb, the lateral circumflex femoral artery arose from the femoral artery (22.2%). There were no significant differences between sexes or sides. Pattern III: Both arteries arose from the femoral artery (2 cases, 0.5%). In every disposition there was a significantly higher prevalence of unilateral rather than bilateral occurrence. In one dissection the medial circumflex femoral artery was absent. Awareness of these variations could avoid unexpected injuries. Clin. Anat. 20:180,185, 2007. © 2006 Wiley-Liss, Inc. [source]

Effect of freezing-thawing on the expression of mannose-ligand receptors on human spermatozoa: the impact on sperm capacitation and acrosome reaction

ANDROLOGIA, Issue 5 2001
H. Yavetz
Summary The aim of this study was to evaluate the change in the expression of mannose-ligand receptors following a freezing-thawing procedure, in order to assess its impact on sperm capacitation and acrosome reaction. Twenty semen samples were obtained from fertile donors. Sperm samples were divided into two equal volumes. One aliquot was cryopreserved and the other aliquot was incubated at 32°C. After 2 h the frozen sample was thawed and both samples were further incubated at 32°C to allow capacitation. Mannose receptors were examined following 4 and 22 h of incubation using a mannosylated-BSA-FITC probe. The expression of mannose-ligand receptors on the sperm plasma membrane was determined according to the fluorescence pattern: pattern I represents pre-capacitation, pattern II represents capacitated spermatozoa and pattern III represents acrosome-reacted spermatozoa. After 4 h incubation in capacitating medium, the percentages of patterns I, II and III were 90, 7 and 3% for fresh spermatozoa and 89, 8 and 3% for frozen-thawed spermatozoa, respectively (P>0.05). Following 22 h of incubation, the percentages of patterns I, II and III were 84, 11 and 5 for fresh spermatozoa and 83, 11 and 6% for frozen-thawed spermatozoa, respectively (not significant at P>0.05). The percentages of patterns II and III in fresh and frozen-thawed spermatozoa were increased by the same magnitude with longer incubation in the capacitating conditions. It was concluded that the freezing-thawing procedure for human spermatozoa does not affect the expression of mannose-ligand receptors and the dynamics of sperm pre-fertilization processes. [source]

Effect of freezing,thawing on the expression of mannose-ligand receptors on human spermatozoa: the impact on sperm capacitation and acrosome reaction

ANDROLOGIA, Issue 5 2001
H. Yavetz
Summary., The aim of this study was to evaluate the change in the expression of mannose-ligand receptors following a freezing,thawing procedure, in order to assess its impact on sperm capacitation and acrosome reaction. Twenty semen samples were obtained from fertile donors. Sperm samples were divided into two equal volumes. One aliquot was cryopreserved and the other aliquot was incubated at 32 °C. After 2 h the frozen sample was thawed and both samples were further incubated at 32 °C to allow capacitation. Mannose receptors were examined following 4 and 22 h of incubation using a mannosylated-BSA-FITC probe. The expression of mannose-ligand receptors on the sperm plasma membrane was determined according to the fluorescence pattern: pattern I represents pre-capacitation, pattern II represents capacitated spermatozoa and pattern III represents acrosome-reacted spermatozoa. After 4 h incubation in capacitating medium, the percentages of patterns I, II and III were 90, 7 and 3% for fresh spermatozoa and 89, 8 and 3% for frozen,thawed spermatozoa, respectively (P > 0.05). Following 22 h of incubation, the percentages of patterns I, II and III were 84, 11 and 5 for fresh spermatozoa and 83, 11 and 6% for frozen,thawed spermatozoa, respectively (not significant at P > 0.05). The percentages of patterns II and III in fresh and frozen,thawed spermatozoa were increased by the same magnitude with longer incubation in the capacitating conditions. It was concluded that the freezing,thawing procedure for human spermatozoa does not affect the expression of mannose-ligand receptors and the dynamics of sperm pre-fertilization processes. [source]

Intrapopulational polymorphism of nucleolus organizer regions in Serrapinnus notomelas (Characidae, Cheirodontinae) from the Paraná River

JOURNAL OF FISH BIOLOGY, Issue 5 2008
A. P. Santi-Rampazzo
Analysis of the nucleolus organizer regions by silver nitrate (AgNOR), fluorescent in situ hybridization (FISH) and C-banding of Serrapinnus notomelas from the Paraná River, PR, Brazil revealed intrapopulational polymorphisms that could be classified into six patterns (I,VI). Pattern I consisted of a single nucleolus organizer region (NOR) on chromosome pair 26 with at least one active homologue, indicating that it was a preferential NO. This NOR was also present in all the other patterns. In addition, seven other variable pairs appeared in patterns II,VI. These polymorphisms may indicate transpositions of rDNA genes, located on pair 26, to various sites in the genome. These transpositions may be due to transpose mechanisms or reinsertion into sites that have sequences homologous with the inserts. C-band analysis also reflected this variability and confirmed the various patterns described here. [source]