39 research outputs found
A rare presentation of the Klinefelter's syndrome
A 16 years old boy with Chronic Renal Failure (CRF) was not suspected of having Klinefelter's syndrome until he complained of painful gynecomastia. He was under haemodialysis for 2 years. At first, he was in an approximately full pubertal development (P5, G5), but he had a small and a firm testis (length 2.2cm) and some degree of facial male pattern hair. He also had a decreased upper to lower body segment ratio and despite having chronic renal failure, he was taller than his parents and siblings. His laboratory tests showed high levels of FSH and normal levels of LH and testosterone. With regards to all these findings, we suspected that there might be an occult Klinefelter's syndrome. So, we made his karyotype that showed a 47XXY pattern. Because there are only a few number of cases that have occult Klinefelter's syndrome in the basis of chronic renal failure, we decided to report this case
Particle dynamics in sheared granular matter
The particle dynamics and shear forces of granular matter in a Couette
geometry are determined experimentally. The normalized tangential velocity
declines strongly with distance from the moving wall, independent of
the shear rate and of the shear dynamics. Local RMS velocity fluctuations
scale with the local velocity gradient to the power . These results agree with a locally Newtonian, continuum model, where the
granular medium is assumed to behave as a liquid with a local temperature
and density dependent viscosity
Self-similar shear-thickening behavior in CTAB/NaSal surfactant solutions
The effect of salt concentration Cs on the critical shear rate required for
the onset of shear thickening and apparent relaxation time of the
shear-thickened phase, has been investigated systematically for dilute
CTAB/NaSal solutions. Experimental data suggest a self-similar behavior of the
critical shear rate and relaxation time as functions of Cs. Specifically, the
former ~ Cs^(-6) whereas the latter ~ Cs^(6) such that an effective Weissenberg
number for the onset of the shear thickened phase is only weakly dependent on
Cs. A procedure has been developed to collapse the apparent shear viscosity
versus shear rate data obtained for various values of Cs into a single master
curve. The effect of Cs on the elastic modulus and mesh size of the
shear-induced gel phase for different surfactant concentrations is discussed.
Experiments performed using different flow cells (Couette and cone-and-plate)
show that the critical shear rate, relaxation time and the maximum viscosity
attained are geometry-independent. The elastic modulus of the gel phase
inferred indirectly by employing simplified hydrodynamic instability analysis
of a sheared gel-fluid interface is in qualitative agreement with that
predicted for an entangled phase of living polymers. A qualitative mechanism
that combines the effect of Cs on average micelle length and Debye parameter
with shear-induced configurational changes of rod-like micelles is proposed to
rationalize the self-similarity of SIS formation.Comment: 27 pages, 17 figure
Random Sequential Adsorption: From Continuum to Lattice and Pre-Patterned Substrates
The random sequential adsorption (RSA) model has served as a paradigm for
diverse phenomena in physical chemistry, as well as in other areas such as
biology, ecology, and sociology. In the present work, we survey aspects of the
RSA model with emphasis on the approach to and properties of jammed states
obtained for large times in continuum deposition versus that on lattice
substrates, and on pre-patterned surfaces. The latter model has been of recent
interest in the context of efforts to use pre-patterning as a tool to improve
selfassembly in micro- and nanoscale surface structure engineering
The history of degenerate (bipartite) extremal graph problems
This paper is a survey on Extremal Graph Theory, primarily focusing on the
case when one of the excluded graphs is bipartite. On one hand we give an
introduction to this field and also describe many important results, methods,
problems, and constructions.Comment: 97 pages, 11 figures, many problems. This is the preliminary version
of our survey presented in Erdos 100. In this version 2 only a citation was
complete
Existence of a Precipitation Threshold in the Electrostatic Precipitation of Oppositely Charged Nanoparticles
Fast Approximation Algorithms for Multicommodity Flow Problems
Fast Approximation Algorithms for Multicommodity Flow Problem