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F de los Santos

Publications and source records attributed to F de los Santos.

5 recordsLinked to original sources
PubMed2004

Diffusion-limited deposition of dipolar particles.

Deposits of dipolar particles are investigated by means of extensive Monte Carlo simulations. We found that the effect of the interactions is described by an initial, nonuniversal, scaling regime characterized by orientationally ordered deposits. In the dipolar regime, the order and geometry of the clusters depend on the strength of the interactions and the magnetic properties are tunable by controlling the growth conditions. At later stages, the growth is dominated by thermal effects and the diffusion-limited universal regime obtains, at finite temperatures. At low temperatures the crossover size increases exponentially as T decreases and at T=0 only the dipolar regime is observed.

Journal Article↗
PubMed2003

Nonequilibrium wetting transitions with short range forces.

We analyze within mean-field theory as well as numerically a Kardar-Parisi-Zhang equation that describes nonequilibrium wetting. Both complete and critical wettitng transitions were found and characterized in detail. For one-dimensional substrates the critical weting temperature is depressed by fluctuations. In addition, we have investigated a region in the space of parameters (temperature and chemical potential) where the wet and nonwet phases coexist. Finite-size scaling analysis of the interfacial detaching times indicates that the finite coexistence region survives in the thermodynamic limit. Within this region we have observed (stable or very long lived) structures related to spatiotemporal intermittency in other systems. In the interfacial representation these structures exhibit perfect triangular (pyramidal) patterns in one dimension (two dimensions), which are characterized by their slope and size distribution.

Journal Article↗
PubMed1996

Estrogen and progesterone receptors, c-erbB-2, p53, and Bcl-2 in thirty-three invasive micropapillary breast carcinomas.

Tests for estrogen (ER) and progesterone (PR) receptors, c-erbB-2, p53 and Bcl-2 were made on paraffin sections of thirty-three cases of invasive micropapillary carcinoma (MPCa) of the breast. The relations between these proteins and general parameters and the patients' evolution, were analyzed and their statistical significance determined by Fisher's exact test. Follow up was available on twenty one patients of whom thirteen were alive after a mean of sixty months. Tumor size, metastatic nodes, c-erbB-2 and Bcl-2 all showed higher values in the dead patient group, but only nuclear grade and extensive lymphatic vessel invasion (LVI) were statistically significant prognostic factors. Hormone receptors and oncogenes were positive in quite similar figures to those of common breast cancers (NOSCa) and offered supplementary information about differentiation and cell atypia of individual cancers. Accordingly, ER (72.7%), PR (45.4%) and Bcl-2 (69.6%) were directly interrelated and inversely related with nuclear grade, mitotic grade, c-erbB-2 (36.3%) and p53 (12.1%). In conclusion, MPCa is a lymphotropic cancer phenotype whose prognosis can be influenced by known prognostic factors, including molecular. The lack of discriminative power between MPCa and NOSCa of ER, PR, c-erbB-2, p53, and Bcl-2 reinforces the importance of recognizing this particular type of cancer.

Adult↗
PubMedDate not supplied

Radial bone mineral content in healthy Mexican women.

Fifty healthy Mexican women from 21 to 70 years of age volunteered to undergo radial bone densitometry. The bone density in ten women per decade was assessed at two sites in the radius of the nondominant forearm; one site was the distal radius at 5 mm of separation from the ulna and the other at one-third of the distal radius. Calcium, inorganic phosphates and alkaline phosphatase were measured in serum samples and the calcium/creatinine ratio in fasting urine samples. Bone density at the distal radius was 360.6 +/- 36.2 mg/cm2, 369.8 +/- 47.9 mg/cm2 and 364.7 +/- 53.7 mg/cm2 in the 21-50 age group. There was no significant difference between these groups; the pooled value of all these samples was 365 +/- 46 mg/cm2. There was significant difference in the 51-60 age group, 290 +/- 48. mg/cm2 (p less than 0.01) and in the 61-70 age group. 277.9 +/- 49.9 mg/cm2 (p less than 0.01). Bone density at the one-third distal radius in the 21-20 age group was 696.3 +/- 60.9 mg/cm2; 31-40, 683.6 +/- 68.4 mg/cm2 and 41-50, 697.9 +/- 53.9 mg/cm2. There was no significant difference among these group; the pool of all these samples showed 692.6 +/- 59.6 mg/cm2. In the 51-60 age group it was 628.0 +/- 63.3 mg/cm2, a non significant difference. On the other hand, the density in the 61-70 group was 573.7 +/- 83.5 mg/cm2, significant (p less than 0.01) when compared to the 21-50 age group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗