Results 1 - 10 of 7194
Results 1 - 10 of 7194. Search took: 0.063 seconds
|Sort by: date | relevance|
[en] It is reasonable to assume that gains in detective quantum efficiency (DQE) are far better criteria for assessing the performance of hypersensitizing techniques than gains in speed. It is shown here that gains in speed can be misleading, for some methods of hypersensitization give plates of increased speed but reduced detective quantum efficiency. (author)
[en] Separate treatments of high temperature had considerable effect on Cl.perfrigens spores suspended in saline solution especially at 90 and 1000C, while 70 and 800C had only slight effect on the spores viabilty. The decimal reduction times (DT) were 33.7, 26, 4, 10.7 and 2.8 at 70, 80, 90 and 1000C for NCTC 8798 strain and were 45.1, 27.1, 10.2 and 4.0 for the Egyptian strain at the same degrees of temperature respectively. Heat treatment pre-irradiation at 70 and 800C for 30 and 60 min decreased the viable spore numbers by about 0.5 to 3.0 log cycles, but the treatment had no effect on increasing the sensitivity of the rest spores to radiation. The decimal reduction dose (D10-value) for the spores was almost the same as the control but there was a tendency to reduce the shoulder part in the radiation response curve especially when the spores were subjected to 800C for 60 min. On the other hand, irradiation pre-heat treatment with doses from 1-10 KGY was sufficient to decrease the spore numbers from 0.2 to 5.0 log cycles and had a sensitizing effect on subsequently heated spores especially those exposed to 90 and 1000C. Meanwhile the rate of inactivation for spores exposed to 70 and 800C after irradiation increased only during the first ten minutes. Thereafter, the rate of inactivation was almost the same for the non-irradiated spores. The D10-values for the spores irradiated with 10 KGY were 0.77 and 0.84 minutes for NCTC 8798 strain and Egyptian strain at 1000C respectively and the spores were completely destroyed before 5 minutes
[en] The unique action of paclitaxel to stabilise microtubules and block cells at the radiosensitive G2/M phase of the cell cycle, suggests it may sensitise tumours to radiotherapy. Since the use of paclitaxel may be compromised in drug resistant tumours due to drug efflux by P-glycoprotein, the ability of paclitaxel to sensitise multidrug resistant cells to radiation was examined in HL60 cells and a multidrug resistant subline, H/E8, developed by intermittent treatment with epirubicin. Poster 201. (author)
[en] Objective: To investigate radiosensitization effect of valproic acid (VPA) on human hepatocellular cell line SMMC-7221 and its mechanism. Methods: MTT was used to detect the proliferation and IC50, of SMMC-7221 cell. FCM was adopted to analyze the changes in cell cycle and apoptosis level. Results: After co-cultured with VPA, the IC50 of SMMC-7221 cell was 41.26, 9.04, 2.87 mmol/L. VPA + IR could significantly inhibit the cell proliferation, increase apoptosis level, cause G0/G1, phase arrest and decrease the decreased the percentages of S phrase. Conclusion: VPA could enhance the cell-killing effect of SMMC-7221 cell as a radio-sensitizer, which was associated with apoptosis and cell cycle arrest. (authors)
[en] In this study, a naphtho-p-quinodimethane (QDM) exhibiting Baird’s 4n - π antiaromaticity was used as green photonsharvesting chromophore to sensitize perylene (Per) leading to upconverted blue photoluminescence. The solution phase QDM → Per triplet energy transfer (TET) could not be unraveled via the Stern-Volmer method, but transient absorption measurements revealed that the kinetics of T1 → Tn for QDM (τ = 1.4 μs) was 1 order of magnitude reduced (τ= 0.17 μs) as a result of 3(Per)* formation. Lastly, we demonstrated that incident light with power densities in the microwatt regime is sufficient to perform photon upconversion using the present set of molecular systems.