• Food Science and Preservation
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• v.16 no.6
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• pp.817-823
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• 2009

We investigated the effects of storage temperature and packaging treatment on the freshness of high-quality 'Fuji' apples to improve consumer confidence in the maintenance of high fruit quality during distribution. A 0.35 mm-deep PET tray form-sealed with a 0.05 mm LDPE film lid was developed and tested with the aim of optimizing gas composition within the package headspace to utilize potential modified atmosphere (MA) storage to maintain the freshness of apples. Weight loss, color difference, firmness, respiration rate, gas concentrations in packages, acidity, solid soluble content, and fruit decay rate were measured during storage at $5^{\circ}C$ and $25^{\circ}C$. The results showed that respiration rate, weight loss, color difference, and firmness were lower and overall quality better during storage at $5^{\circ}C$ compared with $25^{\circ}C$. Also, the fruits packed in the functional tray form showed a low level of quality changes compared with the control (no packaging). The accumulated gasconcentrations in the headspace of the packages decreased from 21% to 12% $O_2$ and increased from 0% to 5% $CO_2$ (v/v) on day 7, and after remained at those levels thereafter. Soluble solid contents and total acidities of the packaged fruits were in the range of $11\;-\;14^{\circ}Brix$ and 0.2 0.3% during storage. Decay rates in the control and packaged fruits were more than 20% and less than 10% at 3 weeks, respectively. Based on the standard acceptable level (less than 10%) of total weight loss, it could be estimated that the shelf life of top-quality fruits packed in functional trays was 3 weeks at $5^{\circ}C$ and 16 weeks at $25^{\circ}C$, whereas the shelf life of the control fruit was 1 week and 12 weeks, respectively. For the top-quality fruit "Fuji" apples, the best results were obtained with a functional tray form for packaging treatment and a storage temperature of $5^{\circ}C$.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.187-193
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• 2006

Background : Normal cell proliferation and viability is strongly depends on the availability of metabolic energy and the maintenance of the appropriate adenylate-nucleotide pools. Hypothetically, changes in adenylate kinase (AK) expression could therefore be associated with adaptation to altered growth characteristics or inversely altered growth characteristics of proliferating cells could drive the changes in the metabolic profile. This study investigated whether the expression of either AK1 or a Mycobacterium tuberculosis adenylate kinase mutant which has the same catalytic activity of AK1 could affect the growth rate of slow-growing BCG. Method : Recombinant BCGs, which were cloned the human muscle-type adenylate kinase synthetic gene (AK1) and adenylate kinase mutation gene (AKmtDM) of Mycobacterium tuberculosis into the Mycobacterium/E.coli expression vectors, were constructed. Recombinant BCGs and wild-type BCG were cultured in 7H9 media and the optical density at 600nm was measured at intervals of 2-3 days. Result : There wasn't the growth rate change induced by AK1 or AKmtDM expression in recombinant BCGs. Conclusion : The expression of AK1 or Mycobacterium tuberculosis adenylate kinase mutant in BCG does not affect the growth rate of BCG.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.