Morphology and dynamics of craterlike structures created by recoiling elongated particles.

We study the morphology and dynamics of craterlike structures formed when free-falling, randomly oriented, elongated particles bounce off a flat surface in a single particle scattering mode. The origin of a sharply defined rim with its associated structure, the factors determining the rim diameter, and the scaling of the diameter with impact velocity are examined. The probability distribution of rebounding particle ranges is calculated for a particular example and shown to provide a precursor description of structure formation.

Dialectical multispectral classification of diffusion-weighted magnetic resonance images as an alternative to apparent diffusion coefficients maps to perform anatomical analysis.

Multispectral image analysis is a relatively promising field of research with applications in several areas, such as medical imaging and satellite monitoring. A considerable number of current methods of analysis are based on parametric statistics. Alternatively, some methods in computational intelligence are inspired by biology and other sciences. Here we claim that philosophy can be also considered as a source of inspiration. This work proposes the objective dialectical method (ODM): a method for classification based on the philosophy of praxis. ODM is instrumental in assembling evolvable mathematical tools to analyze multispectral images. In the case study described in this paper, multispectral images are composed of diffusion-weighted (DW) magnetic resonance (MR) images. The results are compared to ground-truth images produced by polynomial networks using a morphological similarity index. The classification results are used to improve the usual analysis of the apparent diffusion coefficient map. Such results proved that gray and white matter can be distinguished in DW-MR multispectral analysis and, consequently, DW-MR images can also be used to furnish anatomical information.

Evaluation of Alzheimer's disease by analysis of MR images using multilayer perceptrons and committee machines.

Alzheimer's disease is the most common cause of dementia, yet hard to diagnose precisely without invasive techniques, particularly at the onset of the disease. This work approaches image analysis and classification of synthetic multispectral images composed by diffusion-weighted magnetic resonance (MR) cerebral images for the evaluation of cerebrospinal fluid area and its correlation with the advance of Alzheimer's disease. The MR images were acquired from a unique volunteer with Alzheimer's, using an image system based on a clinical 1.5T tomographer. The classification methods are based on multilayer perceptrons and committee machines and the classification results are used to correlate clinical and imaging findings. The classification results are used to improve the usual analysis of the ADC map.

Anisotropic water diffusion in nematic self-assemblies of clay nanoplatelets suspended in water.

Diffusion-weighted magnetic resonance imaging provides a vivid description of the little understood role played by interfacial interactions with macroscopic bodies in the cooperative self-assembly of clay nanoplatelets suspended in water. The interfacial interaction between hydrophilic glass walls and clay platelets in a Na-fluorhectorite gel can produce, for dilute gels, a face-to-wall anchoring of the platelets that leads to a uniaxial nematic order with platelet faces parallel to the walls but with randomly distributed normals of the faces. The application of a magnetic field perpendicular to the walls transforms this uniaxial order to an extended biaxial nematic order with orthogonal alignment between normals and the field. Moreover, for apolar walls, this face-to-wall anchoring is considerably hindered, and the uniaxial nematic order can be substantially disrupted.

Water ingress in Y-type zeolite: anomalous moisture-dependent transport diffusivity.

Nuclear magnetic resonance imaging measurements of liquid water ingress in a large number of nonactivated Y-type (Na) zeolite samples prepared under different conditions are reported on. Using an experimental arrangement that permits the application of Boltzmann's transformation of the 1D (one-dimensional) diffusion equation, the spatiotemporal scaling variables required for a collapse of the measured profiles into universal curves revealed subdiffusive behavior in all cases. It is shown that the one-dimensional fractal time diffusion equation constitutes a powerful tool to analyze the data and provides a connection between the moisture dependence of the effective transport diffusivities and the shapes of the universal curves. Thus, even for anomalous diffusion, the relationship between the universal curves and structural characteristics of the system; such as porosity, tortuosity of the pore space and, in some cases, the interplay between mesopores and nanopores can be addressed.

Scaling properties in the packing of crumpled wires.

Statistical properties of configurations of a metallic wire injected into a transparent planar two-dimensional cavity for three different injection geometries are investigated with the aid of high-resolution digital imaging techniques. The observed patterns of folds are studied as a function of the packing fraction of the wire within the cavity. In particular, we have examined the dependence of the mass of wire within a circle of radius R, as well as the dependence of the number of contacts wire-wire with the packing fraction. The distribution function n(s) of connected loops with internal area s formed as a consequence of the folded structure of the wire, and the average coordination number for these loops are also examined. Several scaling laws connecting variables of physical interest are obtained and discussed and a relation of this problem with disordered two-dimensional foam and random packing of disks is examined.

Crumpled wires in two dimensions.

Geometric and statistical properties of wires injected into a two-dimensional cavity with three different injection geometries are investigated. Complex patterns of folds are observed and studied as a function of the length of the wire. The mass-size relation and the distribution function n(s) of loops with internal area s formed as a consequence of the folded structure of the wire are examined. Several scaling laws are found and a hierarchical model is introduced to explain the experimental behavior observed in this two-dimensional crumpling process.

A rare case of dual obstruction of the colon.

The commonest cause of large bowel obstruction is colorectal malignancy. Volvulus of the colon is a rare cause and caecal volvulus accounts for less than 1% of all cases of intestinal obstruction. Reports of concurrent occurrence of obstructing lesions of the right and left colon are rare and anecdotal. We report a case of Caecal volvulus and carcinoma of the rectosigmoid in a 70-year-old lady.

Ruptured liver abscess with fulminant amoebic colitis: case report with review.

Amoebic liver abscess is the commonest extra intestinal manifestation of amoebiasis. Intraperitoneal rupture of liver abscess and fulminant necrotizing amoebic colitis are rare occurrences which complicate a severe form of invasive disease caused by Entamoeba histolytica. These complications are associated with a high morbidity and mortality. Synchronous pathological lesions in colon and liver are rare. Still rare is the occurrence of complicated colonic and hepatic invasive amoebiasis presenting as an acute abdomen. One such presentation of ruptured liver abscess and necrotizing amoebic colitis in a 70 year old male which was successfully managed is being reported.

Cutaneous histiocytic lesions: a clinical dilemma.

The diagnosis of malignant histiocytosis requires a high index of clinical suspicion, awareness of its atypical features and availability of various tissue samples for morphological and special studies. The case reported here highlights the diagnostic difficulties encountered in a patient diagnosed as malignant histiocytosis who presented with cutaneous lesions in multiple foci, which included the face, groin and forearm. Only after repeated biopsies and special stains, a diagnosis of malignant histiocytosis was arrived at. Chemotherapy with CHOP regimen (cyclophosphamide, doxorubicin, vincristine and prednisone) was initiated. The response to chemotherapy was good and the patient is doing well eleven months after initial diagnosis.

Mobility and free radical concentration effects in proton-electron double-resonance imaging.

The dependence of the enhancement of proton-electron double-resonance images upon the mobility of the proton bearing molecules, of the concentration of free radicals, and of the pulsed saturating RF power is studied in a magnetic field of 16 mT. The data exhibit a behavior which, in the potentially interesting region of small free radical concentration, may differ substantially from the high-concentration regime depending upon experimental conditions. The results permit a clearer understanding of the factors determining enhancement and contrast in images obtained by dynamic nuclear polarization.