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Biomedical subjects

José Alonso

Publications and source records attributed to José Alonso.

13 recordsLinked to original sources
PubMed2006

Design of two-dimensional zero reference codes with a genetic algorithm.

In mask-alignment systems a reference signal is needed to align the mask with the silicon wafers. The optical reference signal is the autocorrelation of two two-dimensional (2D) codes with binary transmittance. For a long time, one-dimensional codes have been used in grating-measurement systems to obtain a reference signal. The design of this type of code has needed a great computational effort, which limits the size of the code to about 100 elements. Recently, we have applied genetic algorithms to design codes with arbitrary length. We propose the application of these algorithms to design 2D codes to generate 2D optical signals used in mask-alignment systems.

Journal Article↗
PubMed2005

Optimal design of optical reference signals by use of a genetic algorithm.

A new technique for the generation of optical reference signals with optimal properties is presented. In grating measurement systems a reference signal is needed to achieve an absolute measurement of the position. The optical signal is the autocorrelation of two codes with binary transmittance. For a long time, the design of this type of code has required great computational effort, which limits the size of the code to approximately 30 elements. Recently, the application of the dividing rectangles (DIRECT) algorithm has allowed the automatic design of codes up to 100 elements. Because of the binary nature of the problem and the parallel processing of the genetic algorithms, these algorithms are efficient tools for obtaining codes with particular autocorrelation properties. We design optimum zero reference codes with arbitrary length by means of a genetic algorithm enhanced with a restricted search operator.

Algorithms↗
PubMed2004

Endovascular treatment of congenital portal vein fistulas with the Amplatzer occlusion device.

Two patients with symptomatic congenital portal vein (PV) fistulas (one case of PV-right hepatic vein fistula and one case of PV-inferior vena cava fistula) causing hepatopulmonary syndrome (hepatic dysfunction, lung vascular alteration in the form of arteriovenous shunts, and hypoxemia) were successfully treated with the Amplatzer patent ductus arteriosus (PDA) occlusion device. This device was chosen in light of the anatomic characteristics of the vascular malformations and the specific properties of the prosthesis, especially those related to relocation and retrievability when not properly positioned. Embolization with an Amplatzer PDA occlusion device should be considered as a useful therapeutic alternative in the treatment of congenital portal fistulas that can obviate complex surgeries.

Child↗
PubMed2004

A recombinant antigen recognized by Fasciola hepatica-infected hosts.

This work reports the detection of specific immunoglobulins (Ig) against rFh8, a recombinant Fasciola hepatica adult worm excretion-secretion antigen, in sera from experimentally (rabbit, Wistar rat, cattle, and sheep), or naturally (human) infected hosts. In the case of laboratory experimental models the study revealed significant differences between rabbits, which recognized the recombinant antigen all along the infection, and Wistar rats, which showed high anti-rFh8 Ig levels only for a short period of the infection. Available sera from experimentally infected cattle and sheep, as well as sera from naturally F. hepatica-infected humans, also contained significant levels of Ig against rFh8, suggesting that Fh8 was produced by F. hepatica at a very early stage of infection in all hosts so far analyzed and that the rFh8 antigen could be used as a tool for the diagnosis of F. hepatica infections.

Animals↗
PubMed2003

Zero reference signal for displacement measuring systems by use of speckle.

An optical method for generating a reference signal for an incremental displacement measurement system is proposed. We achieved this zero reference signal by comparing two speckle patterns arriving from two symmetric diffusers, which are used as natural random codes that are identical only when the reading head is located equidistantly between the diffusers. The comparison of the speckles is obtained either by interference, as in a Michelson interferometer, or by intensity correlations.

Journal Article↗
PubMed2003

Treatment of a radial artery pseudoaneurysm with ultrasound-guided percutaneous thrombin injection in a patient with Behçet's syndrome.

A 57-year-old man with Behçet's syndrome and recurrent deep vein thrombosis of the lower limbs presented with a painful, pulsating mass on the volar aspect of the radial edge of his left wrist. One month before this visit, he had had venous blood drawn from the same site. Using color Doppler sonography, we diagnosed an iatrogenic pseudoaneurysm of the left radial artery, which was then treated with an ultrasound-guided percutaneous injection of thrombin. A follow-up examination 6 months after the treatment revealed complete resolution of the pseudoaneurysm. To our knowledge, this is the first case report to demonstrate the use of this technique for thrombosis of a pseudoaneurysm in a patient with Behçet's syndrome. We believe that the safety, efficiency, speed, and minimal invasiveness of this procedure make it feasible for use as a treatment for peripheral pseudoaneurysms in such patients.

Aneurysm, False↗
PubMed2002

Recurrent intergrowths in the topotactic reduction process of LaBaCuCoO5.2.

A new perovskite-related oxide with the LaBaCuCoO5.2 composition has been stabilised. Its structure can be described as formed by the recurrent intergrowth of two alternating blocks of YBaCuFeO5 (2ac, i.e., two-fold perovskite superlattice) and YBa2Fe3O8 (3ac) structural types. From the starting material LaBaCuCoO5.2-delta (delta = 0), the rigorous control of the oxygen content has allowed the stabilisation of three new five fold perovskite-related superstructures with the compositions delta = 0.4, 0.8 and 1.1, which can also be described as recurrent intergrowths of two blocks showing 2ac and 3ac periodicity. The reduction process takes place through the 3ac periodic blocks, when 0 < delta < 0.8. Further oxygen decrease seems to involve the 2ac periodic blocks made up of pyramidal layers, giving rise to infinite layer units. The stability limit for these fivefold superstructures is delta = 1.1. In agreement with this the as-synthesised materials constitute an example of topotactic reaction, since their basic structure is kept through the reduction process.

Journal Article↗
PubMed2002

Trp-dependent auxin biosynthesis in Arabidopsis: involvement of cytochrome P450s CYP79B2 and CYP79B3.

The plant hormone auxin regulates many aspects of plant growth and development. Although several auxin biosynthetic pathways have been proposed, none of these pathways has been precisely defined at the molecular level. Here we provide in planta evidence that the two Arabidopsis cytochrome P450s, CYP79B2 and CYP79B3, which convert tryptophan (Trp) to indole-3-acetaldoxime (IAOx) in vitro, are critical enzymes in auxin biosynthesis in vivo. IAOx is thus implicated as an important intermediate in auxin biosynthesis. Plants overexpressing CYP79B2 contain elevated levels of free auxin and display auxin overproduction phenotypes. Conversely, cyp79B2 cyp79B3 double mutants have reduced levels of IAA and show growth defects consistent with partial auxin deficiency. Together with previous work on YUCCA, a flavin monooxygenase also implicated in IAOx production, and nitrilases that convert indole-3-acetonitrile to auxin, this work provides a framework for further dissecting auxin biosynthetic pathways and their regulation.

Arabidopsis↗
PubMed2002

Ultrasound-guided percutaneous thrombin injection for treatment of extrarenal pseudoaneurysm after renal transplantation.

A patient who received two kidney transplants was placed on hemodialysis after failure of both grafts. He had complained of abdominal pain during the preceding month and was found to have a pulsating mass in his right pelvic region. Computed tomography and color Doppler studies showed a large pseudoaneurysm of the common iliac artery. We describe the treatment of this lesion by the use of ultrasound-guided thrombin injection. To the best of our knowledge, this is the first report regarding the use of ultrasound-guided percutaneous thrombin injection for treatment of such a pseudoaneurysm.

Administration, Cutaneous↗
PubMed2002

Experimental measurements of generalized grating images.

The term generalized grating imaging is used to describe the process of image formation of a grating using only another grating as imaging system. The moiré and the Lau effects could be regarded as particular cases of such a process. Here we deal with the less-studied case of images formed at finite distances from the gratings, using an extended monochromatic light source. Some experimental results are shown for the images obtained in this last case, and they are compared with theoretical predictions.

Journal Article↗
PubMed2002

Production of human monoclonal antibodies against Galalpha(1-3)Gal.

The hyperacute rejection observed in models of pig-to-human xenotransplantation is mainly because of the presence of natural antibodies in human blood with specificity for the Galalpha(1-3)Gal (Gal) carbohydrate moiety present on the surface of porcine endothelial cells. Human monoclonal anti-Gal antibodies could be of use both in the study of the basic mechanisms of hyperacute rejection as well as in its clinical prevention. In the present study we prepared 42 heterohybridomas (human-mouse) secreting antibodies with specificity for the Gal epitope. All of the antibodies produced were of the IgM isotype, according to a dot-blot assay. Twenty-seven antibodies were further characterized, and shown to be specific for Gal by different methods, including an enzyme-linked immunosorbent assay, in which the plates were sensitized with mouse laminin as a source of Gal. Specificity was also confirmed using purified Gal carbohydrate in a hemagglutination inhibition assay. The antibodies were shown to mediate lysis of Gal-expressing rabbit erythrocytes in the presence of complement. However, the heterohybridomas themselves were shown to express Gal, a result of the mouse P3x63Ag8.653 hybridoma cells used during hybridoma generation. The presence of this epitope on the surface of anti-Gal-producing cells, and on the antibody itself, represents a limitation to the production of high affinity anti-Gal antibodies.

Animals↗
PubMed2002

Three redundant brassinosteroid early response genes encode putative bHLH transcription factors required for normal growth.

Brassinosteroids (BRs) are a class of polyhydroxylated steroids that are important regulators of plant growth and development. We have identified three closely related basic helix-loop-helix (bHLH) transcription factors, BEE1, BEE2, and BEE3, as products of early response genes required for full BR response. Comparison of the phenotypes of plants that overexpress BEE1 with bee1 bee2 bee3 triple-knockout mutant plants suggests that BEE1, BEE2, and BEE3 are functionally redundant positive regulators of BR signaling. Expression of BEE1, BEE2, and BEE3 is also regulated by other hormones, notably abscisic acid (ABA), a known antagonist of BR signaling. Reduced ABA response in plants overexpressing BEE1 suggests that BEE proteins may function as signaling intermediates in multiple pathways.

Abscisic Acid↗