23 research outputs found
A hierarchy of defects in biaxial nematics
We study the topological properties of the manifolds which describe uniaxial and biaxial nematics in order to compare and classify all types of bulk and surface defects that can arise in a nematic liquid crystal. We explain how topological charges can be assigned both to isotropic defects in uniaxial nematics and to uniaxial defects in biaxial nematics; we further see how it is possible to distinguish between isolated surface defects and surface defects which extend in the bulk, and between surface defects which can relax in the bulk and defects forced to stay on the surface
The topological microstructure of defects in liquid crystals
We study the core of line and point defects in nematic liquid crystals. The topological theory of defects allows us to prove that a uniaxial nematic has two ways to avoid a topologically stable defect: either it melts, by becoming isotropic on the putative defect, or a complex biaxial structure arises, that we describe in the paper
Controlled study of oxatomide vs disodium chromoglycate for treating adverse reactions to food
A controlled, cross-over trial was carried out to compare the efficacy and safety of oxatomide vs disodium chromoglycate (DSCG) for treating food allergy and intolerance. Twenty patients (15F, 5M; mean age 36.6 years), with chronic urticaria (twelve patients) or eczema (eight patients) caused by food allergy (ten cases) or food intolerance (ten cases), were treated with oxatomide (60 mg/day in a single evening administration) and with DSCG (2000 mg/day) for six weeks. The two treatments were separated by a 3-week wash-out period. All the patients completed the trial. During the treatment, both drugs succeeded in controlling the symptoms. With oxatomide, the wheals totally disappeared from 75% of the patients (p = 0.00135), the eczematous lesions disappeared from 64% (p = 0.056), and the itching from 70% (p = 0.00012); the figures for DSCG were 33%, 50% (p = 0.038) and 50%, respectively. Both drugs were well tolerated and there was no need to discontinue the treatment of any of the patients
Formation and distribution of point defects on a disclination line near a free nematic interface
Point defects of opposite signs can alternately nucleate on the -1/2 disclination line that forms near the free surface of a confined nematic liquid crystal. We show the existence of metastable configurations consisting of periodic repetitions of such defects. These configurations are characterized by a minimal interdefect spacing that is seen to depend on sample thickness and on an applied electric field. The time evolution of the defect distribution suggests that the defects attract at small distances and repel at large distances
Valutazione della frequenza di allergia o intolleranza alimentare in pazienti affetti da allergia respiratoria
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A Statistical Study for Evolving Arrays of Nematic Point Defects
none3PAOLO BISCARI; GIOVANNA GUIDONE PEROLI; EPIFANIO G. VIRGABiscari, Paolo; GIOVANNA GUIDONE, Peroli; EPIFANIO G., Virg
[Comparison of RAST with an immunoenzyme method in simultaneous determination of IgE specific for numerous air allergens]
Recently, a new immunoenzymatic test (Allergy Screen Profile, ASP) has been proposed for the simultaneous determination of IgE specific for five inhaled allergens (Dermatophagoides, animal dander, trees, grass pollen and Parietaria). For evaluation of this test we compared the results obtained in twenty-seven patients suffering from respiratory allergy with RAST with those obtained using the new test. In 84.3% of cases there was positive concordance between the two tests. The specificity of ASP ranged from 71.4% to 100% and the sensitivity from 76.9% to 95.2% for the different allergens examined. A good correlation between ASP and RAST was particularly evident for Dermatophagoides, animal dander and trees. Therefore, ASP appears to be a suitable test for the simultaneous determination of IgE specific for different allergens
[Treatment of Behcet's syndrome with colchicine]
The aim of the present study was to investigate the usefulness of colchicine in the treatment of Behcet's syndrome. Ten patients suffering from Behcet's syndrome were selected for this purpose. The patients were treated with 1 mg/day of colchicine associated with 1 mg of betametasone during the initial florid phase of the disease. After the acute phase, betametasone was withdrawn. The patients were observed for a period ranging from 5 to 23 months. Biochemical and immunological parameters were measured at time 0 and every month in order to monitor the disease and the possible side effects of colchicine. All patients had a satisfactory control of the disease without showing any toxic effect
Is the Melkersson-Rosenthal syndrome related to the exposure to food additives? A case report
We present a case of Melkersson-Rosenthal syndrome that occurred in an adult patient who experienced intolerance to the food additives sodium benzoate and tartrazine. The main symptoms were the facial swelling, hypertrophy of the gums, and a typical infiltration of lymphocytes and plasma cells around the small vessels observed in the biopsy of the gums. No involvement of facial nerves was present, and other disorders of granulomatosis have been excluded. All clinical manifestations went into remission once the food additives were excluded from the usual diet