Abstract In this paper, a new multiband fractal frequency selective surface (MF-FSS) is proposed. The work presents a new fractal design methodology for FSSs with Swastika fractal patch elements. The proposed MF-FSS includes periodic arrays of metallic patches, printed on a single layer substrate. The structure parametric analysis is carried out in terms of fractal iterations, geometry elements, and unit-cell size. The simple controllable feature of the proposed structure lets us tune the given parameters of FSS geometry to achieve adjustable bandstop filter. The fractal geometry allows us to design compact structures (CP = 54%) that behave like dual-polarized bandstop filters. The designed structure is validated by means of an excellent agreement between the simulation and measurement results. Also, results show the proposed structure presents the most desirable features like fractal compactness, multiband response, dual polarization, excellent angular stability, and controllability. This work presents a fundamental structure that can be applied into the more complex and sophisticated designs in future.

Anatase nanocrystals were successfully synthesized and deposited onto polyacrylonitrile fibers with photocatalytic self-cleaning activity using the sol-gel process at low temperature. The original and treated samples have been characterized by several techniques such as scanning electron microscopy, fourier transform infrared spectroscopy, x-ray diffraction, diffuse reflectance spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The TiO2 nanoparticles, have been found to form a homogeneous thin film on the fiber surface. The photocatalytic activity, tested by measuring the degradation of adsorbed Eosin Yellowish dye. The photoactivity of the titanium dioxide coated fibres is much higher than that observed in case of untreated fibers. The photocatalytic self-cleaning properties of the treated fibers was fully maintained performing several cycles of photodegradation. This preparation technique can be also applied to new fabrics to create self-cleaning properties in them. The thermogravimetric study of PAN/TiO2 composite showed a slight increase of weight loss in the second step, which implied that, the dehydrogenation and oxygen uptake reactions would be promoted by the TiO2 to some extent.

OBJECTIVE: To evaluate the mass treatment of ascariasis in rural areas of Hamadan Province, Islamic Republic of Iran. METHODS: A control programme in rural areas of Hamadan Province, which began in November 1997, involved giving all persons a single dose of 400 mg albendazole at intervals of three months. The efficacy of the treatment was evaluated by the formalin-ether concentration technique for stool examination and by the Stoll quantitative method. FINDINGS: The average rate of infection with Ascaris before treatment was 53.3%, ranging from 40% in Hamadan district to 75% in Toysercan. Two areas, Malayer and Nahavand, were excluded from the programme because the infection rates were only 13% and 4%, respectively. After two years of mass treatment the infection rate had decreased to 6%. The proportion of positive cases excreting only unfertilized eggs increased to 32%. No side-effects of mass treatment were observed. CONCLUSION: Systematic mass treatment giving high coverage proved to be very effective in the control of ascariasis, notwithstanding a lack of other preventive measures.

OBJETIVO: Evaluar el tratamiento masivo de la ascariasis en zonas rurales de la provincia de Hamadan, en la República Islámica del Irán. MÉTODOS: En noviembre de 1997 dio comienzo en zonas rurales de la mencionada provincia un programa de lucha en virtud del cual se administró a todas las personas una dosis única de 400 mg de albendazol a intervalos de tres meses. La eficacia del tratamiento se evaluó empleando la técnica de concentración con formalina-éter para examinar las heces y mediante el método cuantitativo de Stoll. RESULTADOS: La tasa media de infección por Ascaris antes del tratamiento fue del 53,3%, entre el 40% del distrito de Hamadan y el 75% de Toysercan. Dos zonas - Malayer y Nahavand - quedaron excluidas del programa debido a que sus tasas de infección fueron sólo del 13% y el 4%, respectivamente. Al cabo de dos años de tratamiento masivo la tasa de infección había disminuido al 6%. La proporción de casos positivos que excretaban sólo huevos no fecundados aumentó al 32%. No se observaron efectos secundarios asociados al tratamiento masivo. CONCLUSIÓN: El tratamiento masivo sistemático con alta cobertura fue una alternativa muy eficaz para combatir la ascariasis, pese a la falta de otras medidas preventivas.

OBJECTIF: Evaluer le traitement de masse de l'ascaridiase dans les zones rurales de la province de Hamadan (République islamique d'Iran). MÉTHODES: Un programme de lutte, commencé en novembre 1997 dans les zones rurales de la province de Hamadan, consistait à administrer à chaque habitant une dose unique de 400 mg d'albendazole tous les 3 mois. L'efficacité du traitement a été évaluée par examen des selles après concentration (méthode formol-éther) et par la méthode quantitative de Stoll. RÉSULTANTS: Le taux moyen d'infection par Ascaris était de 53,3 % avant traitement, avec des valeurs allant de 40 % dans le district de Hamadan à 75 % à Toysercan. Deux zones, Malayer et Nahavand, ont été exclues du programme en raison de leur faible taux d'infection (13 % et 4 % respectivement). Après deux années de traitement de masse, le taux d'infection est tombé à 6 % et la proportion de cas positifs n'excrétant que des œufs non fécondés est passée à 32 %. Aucun effet secondaire n'a été observé. CONCLUSION: Un traitement de masse systématique avec un fort taux de couverture s'est révélé très efficace pour lutter contre l'ascaridiase, malgré l'absence d'autres mesures préventives.