[Halos and multifocal intraocular lenses: origin and interpretation]. / Halos y lentes intraoculares multifocales: origen e interpretación.

OBJECTIVE: To present the theoretical and experimental characterization of the halo in multifocal intraocular lenses (MIOL). METHOD: The origin of the halo in a MIOL is the overlaying of 2 or more images. Using geometrical optics, it can be demonstrated that the diameter of each halo depends on the addition of the lens (ΔP), the base power (P(d)), and the diameter of the IOL that contributes to the «non-focused¼ focus. In the image plane that corresponds to the distance focus, the halo diameter (δH(d)) is given by: δH(d)=d(pn) ΔP/P(d), where d(pn) is the diameter of the IOL that contributes to the near focus. Analogously, in the near image plane the halo diameter (δH(n)) is: δH(n)=d(pd) ΔP/P(d), where d(pd) is the diameter of the IOL that contributes to the distance focus. Patients perceive halos when they see bright objects over a relatively dark background. In vitro, the halo can be characterized by analyzing the intensity profile of the image of a pinhole that is focused by each of the foci of a MIOL. RESULTS AND CONCLUSIONS: A comparison has been made between the halos induced by different MIOL of the same base power (20D) in an optical bench. As predicted by theory, the larger the addition of the MIOL, the larger the halo diameter. For large pupils and with MIOL with similar aspheric designs and addition (SN6AD3 vs ZMA00), the apodized MIOL has a smaller halo diameter than a non-apodized one in distance vision, while in near vision the size is very similar, but the relative intensity is higher in the apodized MIOL. When comparing lenses with the same diffractive design, but with different spherical-aspheric base design (SN60D3 vs SN6AD3), the halo in distance vision of the spherical MIOL is larger, while in near vision the spherical IOL induces a smaller halo, but with higher intensity due to the spherical aberration of the distance focus in the near image. In the case of a trifocal-diffractive IOL (AT LISA 839MP) the most noticeable characteristic is the double-halo formation due to the 2 non-focused powers.

Albumin nanoparticles improved the stability, nuclear accumulation and anticytomegaloviral activity of a phosphodiester oligonucleotide.

The goal of this study was to evaluate the potential of albumin nanoparticles as a delivery system for antisense oligonucleotides. Nanoparticles were prepared by a coacervation process and cross-linkage with glutaraldehyde. Phosphodiester (PO) and phosphorotioate (PS) oligonucleotides were either adsorbed on the surface of nanoparticles (PO-NPA and PS-NPA) or incorporated in the nanoparticle matrix (PO-NPB and PS-NPB). When PO-loaded nanoparticles were incubated with phosphodiesterase, only NPB was able to keep the oligonucleotide hybridization capability for at least 60 min. The antiviral activity was evaluated in MRC-5 fibroblasts infected with human cytomegalovirus at a MOI of 0.0035. Both PO nanoparticle formulations significantly increased the antiviral activity of free PO (P<0.001) and NPB showed slightly higher efficacies than NPA (P<0.05). On the other hand, PS exhibited significant higher activity than free PO (P<0.001), however, no significant differences were found between PS-nanoparticle and PO-nanoparticle formulations. These findings were well correlated with the intracellular distribution observed for fluorescent oligonucleotide-loaded albumin nanoparticles. Even these carriers delayed and decreased the uptake of PO by MRC-5 cells, they finally induced a diffused cytoplasmic distribution and major nuclear accumulation. In summary, albumin nanoparticles partially protected a PO against enzymatic degradation and improved their presence in the nucleus and thus, increased its efficiency.

Modeling of woven fabric structures based on fourier image analysis.

The periodic woven structures of fabrics can be defined on the basis of the convolution theorem. Here an elementary unit with the minimum number of thread crossings and a nonrectangular two-dimensional comb function for the pattern of repetition is used to define woven structures. The expression derived is more compact than the conventional diagram for weaving, and the parameters that one needs to determine a given fabric can easily be extracted from its Fourier transform. Several results with real samples of the most common structures-plain, twill, and satin-are presented.

Fourier-domain-based angular correlation for quasiperiodic pattern recognition. Applications to web inspection.

A Fourier-domain-based recognition technique is proposed for periodic and quasiperiodic pattern recognition. It is based on the angular correlation of the moduli of the sample and the reference Fourier spectra centered at the maximum central point. As in other correlation techniques, recognition is achieved when a high correlation peak is obtained, and this result occurs when the two spectra coincide. The angular correlation is a one-dimensional function of the rotation angle. The position of the correlation peak indicates the rotation angle between two similar patterns in the original images. Some optimizations for the discrete calculation of the Fourier-domain-based angular correlation are also proposed. Some applications of this technique to web inspection tasks, such as pattern recognition and classification, damaged web evaluation, and detection of defects, are presented and discussed.

Different strategies in optical recognition of polychromatic images.

We treat two different problems in the recognition of polychromatic images: (1) recognition of an object with a given shape and color combination; (2) recognition of an object regardless of its color combination. To solve each problem we propose different strategies. The number of filters and the objects to which the filters are matched vary with the strategy. Phase-only filters have been used to achieve recognition of both problems. Computer results are given for different targets and scenes to show the behavior of the proposed strategies.

Villous damage induced by suction biopsy and by acute ethanol intake in normal human small intestine.

Previous studies by us indicated that ethanol in concentrations of 2.0-4.8% produced subepithelial blebs in the jejunum of the hamster. In the rat, due to rupture of the blebs, there was denudation of the villus tip epithelium. There are nos similar data on humans. Ethanol, in quantities equivalent to 4.8-6.4 ounces of 80 proof whiskey (diluted to 20% w/v), was infused into stomachs of 20 normal human volunteers. Subjects were divided into groups (Gr) according to the amount or type of alcohol given, and site of biopsies (SB). Gr 1:60 g ethanol, SB = jejunum. Gr 2:45 g ethanol, SB = jejunum. Gr 3:45 g ethanol, SB = duodenum. Gr 4:45 g ethanol as 4.8 oz 80 proof whiskey, SB = duodenum. To compare the morphology in the absence and presence of ethanol, biopsies were obtained from each volunteer before ethanol administration (control period), immediately after peak ethanol concentration in the duodenum or jejunum (ethanol period), and when intraluminal ethanol concentration fell towards zero (recovery period). The mean peak intraluminal ethanol concentrations in the four groups varied between 5.69% and 9.37% (w/v). Ethanol-induced damage was evaluated using strict preset criteria. Coded slides were evaluated by two observers. Suction biopsy damaged 18% of the villi even in biopsies obtained during the control period. Ethanol produced a statistically significant increase in the number of damaged villi (mean of all groups 45%, range: 32% in Gr 2 to 62% in Gr 3). During the recovery period the number of damaged villi fell to that seen in control period biopsies. Ethanol, in quantities equivalent to those ingested during moderate drinking, may produce transient damage to the upper small intestine of man. Conversely, ethanol may simply increase the susceptibility of the mucosa to the unavoidable trauma of suction biopsy. However, the histological and ultrastructural changes were similar to those induced by ethanol in small laboratory animals.

Transition from diffuse esophageal spasm to achalasia.

A 19-year-old man first presented with clinical, radiological, and manometric features of diffuse spasm. Within a year his motility disorder progressed to "vigorous" and, finally, classic achalasia. After pneumatic dilatation and subsequent long myotomy, the features of classic achalasia disappeared and he again exhibited radiological and manometric evidence of "vigorous" achalasia. The evolution of this patient's disease provides evidence that diffuse spasm and achalasia are different stages of the same disease and lie at opposite ends of a spectrum of related esophageal motility disorders.

Improvement in esophageal abnormalities in a patient with scleroderma and features of polymyositis.

A patient with clinical features of both scleroderma and polymyositis, including esophageal dysfunction typical of scleroderma is described. Regression of her illness occurred along with manometric improvement in the esophageal dysfunction. Improvement in esophageal abnormalities in scleroderma has not been previously reported.