7 resultados para C-12(6 ) heavy ion

em University of Queensland eSpace - Australia


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To study the dynamics of protein recruitment to DNA lesions, ion beams can be used to generate extremely localized DNA damage within restricted regions of the nuclei. This inhomogeneous spatial distribution of lesions can be visualized indirectly and rapidly in the form of radiation-induced foci using immunocytochemical detection or GFP-tagged DNA repair proteins. To analyze faster protein translocations and a possible contribution of radiation-induced chromatin movement in DNA damage recognition in live cells, we developed a remote-controlled system to obtain high-resolution fluorescence images of living cells during ion irradiation with a frame rate of the order of seconds. Using scratch replication labeling, only minor chromatin movement at sites of ion traversal was observed within the first few minutes of impact. Furthermore, time-lapse images of the GFP-coupled DNA repair protein aprataxin revealed accumulations within seconds at sites of ion hits, indicating a very fast recruitment to damaged sites. Repositioning of the irradiated cells after fixation allowed the comparison of live cell observation with immunocytochemical staining and retrospective etching of ion tracks. These results demonstrate that heavy-ion radiation-induced changes in sub-nuclear structures can be used to determine the kinetics of early protein recruitment in living cells and that the changes are not dependent on large-scale chromatin movement at short times postirradiation. © 2005 by Radiation Research Society.

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The temperature dependence of the structure of the mixed-anion Tutton salt K-2[Cu(H2O)(6)](SO4)(2x)(SeO4)(2-2x) has been determined for crystals with 0, 17, 25, 68, 78, and 100% sulfate over the temperature range of 85-320 K. In every case, the [Cu(H2O)(6)](2+) ion adopts a tetragonally elongated coordination geometry with an orthorhombic distortion. However, for the compounds with 0, 17, and 25% sulfate, the long and intermediate bonds occur on a different pair of water molecules from those with 68, 78, and 100% sulfate. A thermal equilibrium between the two forms is observed for each crystal, with this developing more readily as the proportions of the two counterions become more similar. Attempts to prepare a crystal with approximately equal amounts of sulfate and selenate were unsuccessful. The temperature dependence of the bond lengths has been analyzed using a model in which the Jahn-Teller potential surface of the [Cu(H2O)(6)](2+) ion is perturbed by a lattice-strain interaction. The magnitude and sign of the orthorhombic component of this strain interaction depends on the proportion of sulfate to selenate. Significant deviations from Boltzmann statistics are observed for those crystals exhibiting a large temperature dependence of the average bond lengths, and this may be explained by cooperative interactions between neighboring complexes.

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Verrallina funerea (Theobald) is a brackish water mosquito that is recognised as an important pest and vector in southeast Queensland, Australia. Immature development time and survival of Ve. funerea was defined in the laboratory in response to a range of temperatures (17-34 degrees C) and salinities (0-35 parts per thousand (p.p.t)). The expression of autogeny in this species was also assessed. Salinity only had a slight effect on mean development time from hatching to adult emergence (7.0-7.4 d at salinities of 0, 17.5 and 31.5 p.p.t) and survival was uniformly high (97.5-99.0%). Mean development times were shorter at 26, 29 and 32 degrees C (7.0, 6.8 and 6.8 d, respectively) and longest at 17 degrees C (12.2 d). The threshold temperature (t) was 5.8 degrees C and the thermal constant (K) was 142.9 degree-days above t. Survival to adulthood decreased from > 95% (at 17-29 degrees C) to 78% (at 32 degrees C) and 0% (at 34 degrees C). No expression of autogeny was observed. Immature development times of Ve. funerea, Ochlerotatus vigilax (Skuse) and Oc. procax (Skuse) were then determined under field conditions at Maroochy Shire. Following tide and rain inundation, cohorts of newly hatched larvae were monitored daily by dipping, and time until pupation was noted. Tidal inundation triggered hatching of Ve. funerea and Oc. vigilax larvae whereas Oc. procax larvae were found only after rain inundation. Estimates of Ve. funerea and Oc. vigilax field development times were similar (8-9 d) while Oc. procax development time was slightly longer (9-10 d). Based on these survey results, control activities targeting Ve. funerea must be initiated 4 d (if using Bacillus thuringiensis var. israelensis de Barjac) or 5 d (if using s-methoprene) after inundation. However, Casuarina glauca Sieber canopy and branchlets covering breeding habitats may present a problem for the penetration of such treatments.

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Question Do different sitting postures require different levels of pelvic floor and abdominal muscle activity in healthy women? Design Observational study. Participants Eight parous women with no pelvic floor dysfunction. Outcome measures Bilateral activity of pelvic floor muscles (assessed vaginally) and two abdominal muscles, obliquus internus abdominis and obliquus externus abdominis, during three sitting postures. Results There was a significant increase in pelvic floor muscle activity from slump supported sitting (mean 7.2% maximal voluntary contraction, SD 4.8) to both upright unsupported sifting (mean 12.6% maximal voluntary contraction, SD 7.8) (p = 0.01) and very tall unsupported sitting (mean 24.3% maximal voluntary contraction, SD 14.2) (p = 0.004). Activity in both abdominal muscles also increased but did not reach statistical significance. Conclusion Both unsupported sitting postures require greater pelvic floor muscle activity than the supported sitting posture.

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The feasibility of sequential carboplatin followed by docetaxel-based therapy for untreated ovarian cancer was determined. Patients received four q3w cycles of carboplatin AUC 7, then four q3w cycles of either docetaxel 100 mg m(-2) (day 1) (arm A); docetaxel 75 mg m(-2) (day 8) and gemcitabine 1250 mg m(-2) (days 1,8) (arm B) or docetaxel 25 mg m(-2) and gemcitabine 800 mg m(-2) (both given weekly (days 1,8,15)) (arm C). A total of 44 patients were randomised to each treatment arm. None of the arms demonstrated an eight cycle completion rate (70.5/72.7/45.5% in arms A/B/C, respectively), which was statistically greater than 60% (P = 0.102, P = 0.056, P = 0.982) which was our formal feasibility criteria, although only the completion rate in arm C was clearly worse than this level. The overall response rate (ORR) after carboplatin was 65.7% in 70 evaluable patients. In evaluable patients, ORRs after docetaxel-based cycles were: arm A 84.0% (21 out of 25); arm B 77.3% (17 out of 22); arm C 69.6% (16 out of 23). At follow-up (median 30 months), median progression-free survival times were: arm A 15.5 months (95% Cl: 10.5 - 20.6); arm B 18.1 months (95% Cl: 15.9 - 20.3); arm C, 13.7 months (95% Cl: 12.8 - 14.6). Neutropenia was the predominant grade 3 - 4 haematological toxicity: 77.8/85.7/54.4% in arms A/B/C, respectively. Dyspnoea was markedly increased in both gemcitabine-containing arms (P = 0.001) but was worse in arm C. Although just failing to rule out eight cycle completion rates less than 60%, within the statistical limitations of these small cohorts, the overall results for arms A and B are encouraging. Larger phase III studies are required to test these combinations.

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Background. Previous studies have identified no strong correlation between patients' height and tracheal length in anaesthetized patients. We have attempted to compare vocal cords-carina distance (VCD) in Chinese patients with the dimensions of five commonly used tracheal tubes. In addition, we attempted to find a surface anatomy measurement that would identify patients with 'short tracheas'. Methods. We measured VCD in 130 anaesthetized Chinese patients with a fibreoptic bronchoscope. Also measurements were obtained of the distal ends of five commonly used tracheal tubes. We undertook various surface anatomy measurements on the patients' chest and neck region to predict those patients with short tracheas. Results. VCD averaged 12.6 ((SD) 1.4) cm. In seven patients (5%) this distance was particularly short (between 8.8 and 10.4 cm). Many of the commonly used tracheal tubes would be placed close to or beyond the carina when the black intubation guide mark(s) is (are) at the level of the vocal cords. The VCD of