Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets.

Efficient and safe production of molybdenum-99 (99Mo) radiopharmaceutical at Tehran Research Reactor (TRR) via fission of LEU targets is studied. Neutronic calculations are performed to evaluate produced 99Mo activity, core neutronic safety parameters and also the power deposition values in target plates during a 7 days irradiation interval. Thermal-hydraulic analysis has been also carried out to obtain thermal behavior of these plates. Using Thermal-hydraulic analysis, it can be concluded that the safety parameters are satisfied in the current study. Consequently, the present neutronic and thermal-hydraulic calculations show efficient 99Mo production is accessible at significant activity values in TRR current core configuration.

Computational investigation of 99Mo production yield via proton irradiation of natU and ²³²Th targets.

Accelerators have some advantages such as safety and cheaper operating and decommissioning costs for (99)Mo production. Yield theoretical calculation using computational codes can powerfully estimate usefulness of a proposed nuclear reaction for a routine manufacturing. In this work, Monte Carlo-based code was used to compute (99)Mo yield in (232)Th and (nat)U proton-irradiated targets, as well as maximum applicable beam current. Results showed that the code well agrees with published experimental data. The targets can bear maximum beam current of 30 µA. Targets from (232)Th provides higher (99)Mo yield.

Cloning of Vibrio cholerae outer membrane protein W in Pichia pastoris.

BACKGROUND AND OBJECTIVE: The outer membrane protein W (ompW) of Vibrio cholerae is involved in stimulating the immune response via induction of protective immunity. It also plays an important role in bacterial pathogenesis by increasing the adaptability of pathogenic strains. In this study we aimed to clone V. cholerae ompW gene in the strain X-33 of Pichia pastoris. MATERIALS AND METHODS: A gene encoding ompW was cloned into the Ppicza vector downstream of alcohol oxidase promoter. Then recombinant vector was transformed into the genome of the strain X-33 of P. pastoris. After growth of zeocin-resistant transformants, clones were selected and subsequently confirmed for cloning by PCR enzymatic digestion and sequencing. RESULTS: PCR, enzymatic digestion and sequencing showed that the ompW gene was correctly cloned into P. pastoris genome. CONCLUSION: Results of our study showed that the methylotrophic yeast P. pastoris can be considered as an appropriate host instead of mammalian and prokaryotic systems for cloning of ompW. As far as data show, this is the first time that ompW of V. cholera is cloned into the methylotrophic P. pastoris.

A cholera outbreak associated with drinking contaminated well water.

BACKGROUND: Cholera has been a significant public health challenge in many communities. An outbreak of acute diarrheal illness occurred among participants in a wedding ceremony in a village in Qazvin, Iran, in 2008. We conducted an epidemiological, environmental and microbiological investigation to determine the causative agent, source and extent of this outbreak. METHODS: Clinical and environmental samples were collected and analyzed for the presence of diarrhea-causing bacterial organisms, which included Vibrio cholera. The relationship between the strains was determined using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). RESULTS: The attack rate was 21.8%. Clinical and environmental samples were positive for V. cholerae serotype Inaba. All tested isolates had a similar ERIC-PCR pattern, which indicated that a single clone of V. cholerae was responsible for this outbreak. CONCLUSION: Our findings demonstrated that well water was the source of this outbreak.