Institution
Simón Bolívar University
Education•Caracas, Venezuela•
About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.
Topics: Population, Crystallization, Context (language use), Nucleation, Differential scanning calorimetry
Papers published on a yearly basis
Papers
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TL;DR: The crystallization kinetics and morphology of biodegradable and double crystalline poly(l-lactide)-b-poly(e-caprolactone) diblock copolymers (PLLA-b-PCL) was studied in a wide composition range by differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM).
Abstract: The crystallization kinetics and morphology of biodegradable and double crystalline poly(l-lactide)-b-poly(e-caprolactone) diblock copolymers (PLLA-b-PCL) was studied in a wide composition range by differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). The two blocks were found to be partially miscible according to the variations of their thermal transitions with composition. PLOM results showed that PLLA crystallizes in a wide composition range with a spherulitic superstructural morphology. Only when the PLLA content is as low as 10 wt % are axialites formed. These results were in good agreement with the overall crystallization kinetics obtained by DSC isothermal experiments and analyzed by the Avrami equation. Both overall crystallization rates and spherulitic growth rates of the PLLA block decrease with PCL content because PCL acts as a diluent for the PLLA block in view of their miscibility. Reorganization processes revealed as double melting peaks for the PLLA block (n...
157 citations
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TL;DR: Pre-P2 levels show a significant positive correlation with the P1/P2 ratio, with the presence of other proteins and, at low pre-P3 levels, with TUNEL-positive sperm, suggesting a link between deficient protamine processing and decreased DNA integrity.
Abstract: BACKGROUND: The protamine 1-to-protamine 2 ratio (P1/P2) is altered in the sperm cells of some infertile patients. Also, evidence for increased protamine 2 precursors (pre-P2) in a few patients has been reported. But so far, there have been no studies measuring simultaneously these two variables in a large number of patients. METHODS: We measured the P1/P2 ratio and the presence of pre-P2 using, for the first time, an antibody specific to the precursor pre-P2, together with other sperm parameters in 224 infertile patients. Additionally, the DNA integrity was assessed by terminal transferase dUTP nick-end labelling (TUNEL) in a subset of the samples. RESULTS: Pre-P2 levels show a significant positive correlation with the P1/P2 ratio, with the presence of other proteins and, at low pre-P2 levels, with TUNEL-positive sperm. An inverse correlation with sperm count, normal morphology and motility was detected. CONCLUSIONS: The levels of pre-P2 may provide clues into the pathogenic mechanisms of infertility. The increased proportion of pre-P2 in some patients with increased P1/P2 ratio suggests an involvement of pre-P2 processing. The positive correlation between TUNEL-positive sperm and pre-P2 at low pre-P2/P2 ratios also suggests a link between deficient protamine processing and decreased DNA integrity.
157 citations
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TL;DR: In this article, the perforation of composite sandwich structures subjected to high-velocity impact was analyzed, and the contribution of failure mechanisms to the energy-absorption of the projectile kinetic energy was determined.
157 citations
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TL;DR: In this paper, Bertini theorems for hypersurface sections containing a subscheme are given for the case of hypersurfaces containing a single subspace and a single component.
Abstract: (1979). Bertini theorems for hypersurface sections containing a subscheme. Communications in Algebra: Vol. 7, No. 8, pp. 775-790.
153 citations
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TL;DR: An analytical solution of the time-dependent diffusion current to square, hexagonal and random arrays of microelectrodes has been obtained by consideration of the overlap of circular diffusion zones extending from each micro-electrode in the array.
153 citations
Authors
Showing all 5925 results
Name | H-index | Papers | Citations |
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Franco Nori | 114 | 1117 | 63808 |
Ignacio Rodriguez-Iturbe | 96 | 334 | 32283 |
Ian W. Hamley | 78 | 469 | 25800 |
Francisco Zaera | 73 | 432 | 19907 |
Thomas G. Habetler | 73 | 395 | 20725 |
Douglas L. Jones | 70 | 512 | 21596 |
I. Taboada | 66 | 346 | 13528 |
Enrique Herrero | 64 | 242 | 11653 |
Rudi Studer | 60 | 268 | 19876 |
Alejandro J. Müller | 58 | 420 | 12410 |
David Padua | 58 | 243 | 11155 |
Rudolf Jaffé | 58 | 182 | 10268 |
Luis Balicas | 57 | 328 | 14114 |
Volker Abetz | 55 | 386 | 11583 |
Ananias A. Escalante | 51 | 160 | 8866 |