Comparison of three copromicroscopic methods to assess albendazole efficacy against soil-transmitted helminth infections in school-aged children on Pemba Island

Background The diagnostic accuracy of three faecal egg count techniques (Kato-Katz, McMaster and FLOTAC) to assess albendazole efficacy against soil-transmitted helminth (STH) infections was compared. Methods The study is registered with Current Controlled Trials [identifier: ISRCTN90088840]. During September-November 2009, 304 school-aged children on Pemba Island, Tanzania, were screened and those infected with Ascaris lumbricoides, hookworm or Trichuris trichiura were treated with a single dose of albendazole (400 mg). Twenty-one days post-treatment, children provided a single stool sample which was examined using the same diagnostic methods. All stool samples were divided into two aliquots and one was fixed in 5% formalin and examined using FLOTAC and McMaster approximately 6 months after collection. Results Using fresh stool samples, comparable prevalences were demonstrated for the three methods at baseline (90-92.2% for T. trichiura, 41.1-52.8% for hookworm, 32.9-37.2% for A. lumbricoides); FLOTAC was the most sensitive method at baseline and follow-up. Albendazole showed high cure rate (CR) against A.lumbricoides (90-97%), moderate CR against hookworm (63-72%) and very low CR against T.trichiura (6-9%), regardless of the technique used. Egg counts (eggs per gram) at baseline were similar for A. lumbricoides and for hookworm among the three methods, and higher using McMaster and Kato-Katz compared with FLOTAC for T. trichiura. All methods were similar for hookworm and A. lumbricoides egg reduction rate (ERR) estimation, but Kato-Katz indicated a significantly higher ERR than McMaster and FLOTAC for T. trichiura. Preserved stool samples revealed consistently lower FECs at baseline and follow-up for all STHs. Conclusion Further development and validation of standard protocols for anthelminthic drug efficacy evaluation must be pursue

Charge collection and capacitance–voltage analysis in irradiated n-type magnetic Czochralski silicon detectors

Abstract The depletion depth of irradiated n-type silicon microstrip detectors can be inferred from both the reciprocal capacitance and from the amount of collected charge. Capacitance voltage ( C – V ) measurements at different frequencies and temperatures are being compared with the bias voltage dependence of the charge collection on an irradiated n-type magnetic Czochralski silicon detector. Good agreement between the reciprocal capacitance and the median collected charge is found when the frequency of the C – V measurement is selected such that it scales with the temperature dependence of the leakage current. Measuring C – V characteristics at prescribed combinations of temperature and frequency allows then a realistic estimate of the depletion characteristics of irradiated silicon strip detectors based on C – V data alone

Development of 3D detectors at FBK-irst

We report on the development of 3D detectors at Fondazione Bruno Kessler - irst in the framework of the CERN RD-50 Collaboration. Technological and design aspects dealing with the 3D Single Type Column detectors are reviewed, and selected results from the electrical and functional characterization of prototypes are reported and discussed. A new detector concept, namely 3D Double-side Double Type Column detectors, allowing for significant performance enhancement while maintaining a reasonable process complexity, is final ly addressed

Localized energy levels generated in Magnetic Czochralski silicon by proton irradiation and their influence on the sign of space charge density

The microscopic damage produced in diodes made of n-type Magnetic Czochralski (MCz) silicon by 24 GeV and 26MeV protons, up to the fluence of 1.3x1015 cm-2 1MeV equivalent neutrons, has been investigated and results are compared to the damage produced in devices made of standard Floating Zone (STFZ) silicon. It is found by means of Thermally Stimulated Currents (TSC) that the production of a radiation induced charged defect is enhanced in MCz, and might be in part responsible for the differences observed in the two materials at room temperature. The influence of defects on the sign of the space charge density has been studied by current transients at constant temperature i(T,t) and by Transient Current Technique (TCT). Type inversion is not revealed up to the highest investigated fluence. Full depletion voltage Vdep measurements versus fluence exhibits a minimum close to 2x1014 cm-2 1MeV equivalent neutrons; at the same fluence, Vdep measured as a function of annealing time changes its initial slope from positive to negative. It is shown by numerical simulations that these features can be accounted by the formation of a double junction, even in absence of type inversion

Immigrants living in an urban milieu with sanitation in Southern Italy: persistence and transmission of intestinal parasites

In the current era of globalization, the massive movement of populations to developed countries causes a greater attention to neglected tropical diseases in places where such diseases are considered unusual. The present study was planned to assess the persistence of intestinal parasitosis in immigrants stably living in the urban central area of Naples (Southern Italy) and the spread of infection within households with a lifestyle similar to that of the country of origin. A total of 2150 stool samples were analysed with the FLOTAC dual technique, and 415 subjects (19.3 %) tested positive for pathogenic intestinal parasites. One hundred ninety-six subjects were randomly selected and monitored again after 1 year in order to evaluate the persistence of intestinal parasites in immigrants having access to proper sanitation. No pathogenic parasites were found in these 196 samples. A total of 482 cohabitants of 151 positive subjects were recruited to evaluate the interfamilial spread of the identified parasites. Only in 18 households were there subjects infected with the same parasite. Monitoring of parasites in stool samples of immigrants showed a decrease of almost all pathogenic species over the years. From the analysis of households, it is not possible to assert that there is a familial transmission. Our study provides evidence that the prevalence of parasitic infections in immigrants is likely related to the poor sanitary habits of the country of origin and that acquisition of new sanitary regulations, together with the administration of pharmacological treatment, limits the transmission in the households and in the local population of their destination