207 research outputs found

    Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

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    Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 μM of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

    1.19 Calcium Phosphate Ceramics With Inorganic Additives ☆

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    The use of inorganic compounds as synthetic growth factors is a promising approach for improving the biological properties of existing synthetic bone graft substitutes such as calcium phosphates. In this article we have described some of the inorganic additives that may improve the capabilities of calcium phosphates, and help bridge the gap toward autograft?s performance known as gold standard for bone regeneration. This article focuses on the specific roles of bioinorganics in processes related to bone formation and resorption and how these modify the biological properties of calcium phosphates, and finally provides insight into the future of this field

    Half-Seed Analysis for Comparing Linolenic Acid Synthesis Between High and Low Oleic Acid Sunflower Inbred Lines

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    The modification of fatty acid composition of two sunflowers inbred lines, HA89 and R978, low oleic acid (normal) and high oleic acid (mutant) respectively, in seeds and during the first stages of growth (A1-B2) was studied under controlled conditions. Enzymatic mechanisms have great effect on the catabolism of seed stored lipids. Temperature and oxygen regulation influence developing sunflower seeds. For simultaneous study of seed and developing seed, half-seed analysis technique was used. The behavior of the fatty acids during the germination in cotyledon of seed showed the increase of linolenic acid in both lines, demonstrating the activity of linoleic acid desaturase (\uc46-desaturase). But linoleic acid as a substrate for linoleate desaturase increased during all stages of developing only in mutant line that revealed higher activity of oleic acid desaturase (\uc412-desaturase) in transforming oleic acid to linoleic acid in this line, and lower activity of this enzyme in low oleic acid line, the reasons probably being the low availability of substrate of this enzyme in low oleic acid line and the complexity of enzymatic mechanisms. The modification of fatty acids in developing sunflower, depends not only on ambient conditions such as temperature and oxygen regulation as described by many authors, but also on the genotype. \ua9 2004, by Walter de Gruyter Berlin/Boston. All rights reserved

    An investigation of the influencing factors for occupants' operation of windows in apartments equipped with portable air purifiers

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    As operations of windows by occupants can greatly affect building energy consumption and indoor air quality, understanding the driving factors of this adaptive control behaviour is of great importance. The present paper reports on an investigation into the influencing factors for window operation behaviour in eighteen newly-built, low-energy apartments in London, UK. A range of indoor and outdoor environmental variables (including temperature, relative humidity, CO2 and particulate matter) as well as the window status (open/closed) were monitored for 6–11 months. About half of the apartments included monitoring for nearly three months during a national pandemic lockdown. Additionally, each apartment was provided with a portable home air purifier (HAP) to use during most of the study period. The effects of environmental variables and the use of HAPs on occupants' operations of windows in the main bedroom were analysed according to different periods (free-running, heating and lockdown period) and occupancy stages (arrival, departure and intermediate occupied times). Results indicated that analysing the heating period alone could lead to explanations of window operation behaviour that were contradictory to those from analysing other periods, and separating the dataset based on different occupancy stages to develop behaviour models was of little value. The results of statistical significance tests showed that indoor temperature was the leading driving factor for occupants’ window opening and closing behaviour, whereas neither air quality-related variables nor the use of air purifiers had a statistically significant impact on window operation behaviour

    Peganum harmala L.'s anti-growth effect on a breast cancer cell line

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    This research was done to evaluate the induction of apoptosis in MDA-MB-231 breast cancer cell line by Peganum harmala's extract, in which a significant amount of \u3b2-carbolines is included. The apoptosis incidence was assessed through Annexin-V-Flous kit. The expressions of genes through which intrinsic apoptosis pathway are involved, Bax, Bcl-2, Bid, and Puma, over the genes the expressions of which are linked to extrinsic apoptosis pathway, TRAIL, Caspase8, p21, and p53, were examined by RT-PCR and Real-time PCR. The results demonstrate that the extract decreases the growth rate of the cancer cell line through inducing apoptosis mechanism. As long as the expression of anti-apoptosis Bcl-2 gen reduced dramatically, an over-expression in Bax and Puma genes was monitored indicating activation of intrinsic apoptosis pathway. A notable over-expression observed with TRAIL and Caspase8 genes as well as Bid gene. The latter is an intermediate for both intrinsic and extrinsic pathways of apoptosis. \ua9 2015 The Author

    An investigation on resistance of 19 common bean genotypes to two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), in three regions of Iran

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    Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of common bean that causes serious damage to agricultural crops. In this study, nineteen common bean genotypes were evaluated for resistance to the two-spotted spider mite. The trial was carried out at field conditions of Karaj, Brojerd and Khomein. One week after mite infestation, the total number of female and eggs were counted for two times. Also, mite damage feeding was evaluated with a 1-6 scale. Khomein had the fewest infested mean and relative resistance of many genotypes was failed in comparison to susceptible standard genotype (Akhtar) at Khomein. So they should be eliminated in alternative breeding programs. Nevertheless, only Ks41128 that had good relative resistance at other regions had the most relative resistance at Khomein. Subsequently, we propose Ks41128 as the most resistance and also the most stable genotypes
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