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A waveguide geometry of some interest consists of a symmetrical pair of ridges in a rectangular waveguide. The paper gives the even and odd mode cut-off spaces of such a structure in addition to its corresponding standing wave patterns. The classic power-voltage, power-current and voltage-current definitions of impedance of the two solutions are also evaluated. The calculations are based on a mode matching procedure and are verified separately using a finite element solver. A knowledge of these parameters is sufficient for the design of a proximity, reverse, directional coupler. [ABSTRACT FROM AUTHOR]

The characteristics of optical bistability in a vertical-cavity semiconductor optical amplifier (VCSOA) operated in reflection are reported. The dependences of the optical bistability in VCSOAs on the initial phase detuning and on the applied bias current are analyzed. The optical bistability is also studied for different numbers of superimposed periods in the top distributed bragg reflector (DBR) that conform the internal cavity ot the device. The appearance of the X-bistable and the clockwise bistable loops is predicted theoretically in a VCSOA operated in reflection for the first time, to the best of our knowledge. Moreover, it is also predicted that the control of the VCSOA's top reflectivity by the addition of new superimposed periods in its top DBR reduces by on order of magnitude the input power needed for the assessment of the X- and the clockwise bistable loop, compared to that required in in-plane semiconductor optical amplifiers. These results, added to the ease of fabricating two-dimensional arrays of this kind of device could be useful for the development of new optical logic or optical signal regeneration devices. [ABSTRACT FROM AUTHOR]

The discontinuity effect at a step between any two waveguides is an important aspect in the design of impedance steps and filter structures. The purpose of this paper is to characterise the effect between a regular rectangular waveguide and a triple ridge waveguide propagating its dominant mode. One method of achieving this is to employ a 180° UE in conjunction with a calculation of the characteristic impedance and wavelength of the ridge waveguide. Another method is to have recourse to its odd-mode eigen-network. Both procedures are employed in order to obtain data on such a discontinuity. Results are in accord with separate calculations using a commercial finite element (FE) solver. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the efficacy and tolerability of flutrimazole 1% powder vs. bifonazole 1% powder in treating tinea pedis. A multicentre, double blind, randomized, parallel and comparative study was conducted. Two hundred and twenty-two patients with clinically and mycologically confirmed tinea pedis were randomized to flutrimazole (n = 136) or bifonazole (n = 138) 1% powder applied twice daily for 4 weeks. The corresponding clinical cure rates were assessed at 2 and 4 weeks of treatment, and the global (clinical and mycological) cure rates were determined at the fourth week. Clinical cure rates were 83.5 and 82.4% for flutrimazole and bifonazole, respectively (95% CI: -0.0806 to 0.1009). Global cure rates were observed in 65.3 and 70.1% of patients treated with flutrimazole and bifonazole, respectively (95% CI: -0.0828 to 0.1779). Three non serious adverse events at the application site - itching (one patient per group) and dishydrotic eczema (one patient treated with flutrimazole) -- were recorded during the study. These results support that flutrimazol 1% powder applied twice daily for a duration of 4 weeks is highly effective in the treatment of tinea pedis, showing a similar therapeutic profile with that of bifonazole 1% powder. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the heterogeneity of cumulus cells that occurs in human cumuli associated with oviductal oocytes and fertilized eggs. Transmission electron microscopy was used to study the cumulus masses surrounding both unfertilized oocytes and fertilized eggs (a pronuclear and a 4-cell stage) recovered at different intervals after ovulation. The specimens were obtained by flushing the oviducts of normal cycling women who underwent surgical sterilization. The cumuli were expanded due to large and irregular intercellular spaces; small linear gap junctions were seen at cell contacts, whereas annular gap junctions were found only in the cytoplasm of some cells. Both types of junction were less abundant in fertilized specimens. Cells surrounding fertilized eggs projected numerous long, thin microvilli into the intercellular spaces. As a rule, the inner layer of the cumulus mass (corona cells) was composed of cells whose surface was relatively smooth. Cumulus cells showed oval nuclei with one or more nucleoli. The cytoplasm of most cells possessed abundant organelles typical of steroidosynthesis: (i) mitochondria with tubular or villiform cristae; (ii) a well-developed smooth endoplasmic reticulum; and (iii) electron dense lipid droplets often surrounded by a few concentric membranes of smooth endoplasmic reticulum and/or in close contact with microtubules and microfilaments. Microperoxisome-like structures were also present. After fertilization, an enhancement of the steroidosynthetic characteristics occurred in the outer layers of the cumulus mass, but not in the corona cells, which still appeared capable of protidosynthesis. Together, these morphological features support the hypothesis that the cumulus of oviductal oocytes and particularly of fertilized eggs, luteinizes like parietal granulosa cells, generating a steroid hormonal micro-environment in the oviduct which may affect fertilization and zygote segmentation. Cumulus cells showing spermiophagic activity, as well as activated macrophages, leukocytes and red blood cells, were also found in the cumulus mass. The macrophages may play a local role both by phagocytic activity and by modulating the steroid secretion of the neighbouring cumulus cells which occurs in the ovarian follicle and corpus luteum. In conclusion, the cumulus mass surrounding tubal oocytes and fertilized eggs appears to be a heterogeneous and dynamic system, in which the micro-environment for fertilization and early embryo development is provided by diverse cell populations in addition to the oviductal cells. [ABSTRACT FROM AUTHOR]