932 resultados para Titanate, Nanofibre, Ion Exchange, Removal of Radioactive Ions, Adsorbent
Resumo:
Objective: Partial nephrectomy for small kidney tumors has increased in the last decades, and the approach to non-palpable endophytic tumors became a challenge, with larger chances of positive margins or complications. The aim of this study is to describe an alternative nephron-sparing approach for small endophytic kidney tumors through anatrophic nephrotomy. Patients and Methods: A retrospective analysis of patients undergoing partial nephrectomy at our institution was performed and the subjects with endophytic tumors treated with anatrophic nephrotomy were identified. Patient demographics, perioperative outcomes and oncological results were evaluated. Results: Among the partial nephrectomies performed for intraparenchymal tumors between 06/2006 and 06/2010, ten patients were submitted to anatrophic nephrotomy. The mean patient age was 42 yrs, and the mean tumor size was 2.3 cm. Mean warm ischemia time was 22.4 min and the histopathological analysis showed 80% of clear cell carcinomas. At a mean follow-up of 36 months, no significant creatinine changes or local or systemic recurrences were observed. Conclusion: The operative technique described is a safe and effective nephron-sparing option for complete removal of endophytic renal tumors.
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This study evaluated linear alkylbenzene sulfonate removal in an expanded granular sludge bed reactor with hydraulic retention times of 26 h and 32 h. Sludge bed and separator phase biomass were phylogenetically characterized (sequencing 16S rRNA) and quantified (most probable number) to determine the total anaerobic bacteria and methanogenic Archaea. The reactor was fed with a mineral medium supplemented with 14 mg l(-1) LAS, ethanol and methanol. The stage I-32 h consisted of biomass adaptation (without LAS influent) until reactor stability was achieved (COD removal >97%). In stage II-32 h, LAS removal was 74% due to factors such as dilution, degradation and adsorption. Higher HRT values increased the LAS removal (stage III: 26 h - 48% and stage IV: 32 h - 64%), probably due to increased contact time between the biomass and LAS. The clone libraries were different between samples from the sludge bed (Synergitetes and Proteobacteria) and the separator phase (Firmicutes and Proteobacteria) biomass. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
The addition of Cu2+ ions to the classical Fenton reaction (Fe2+ plus H2O2 at pH 3) is found to accelerate the degradation of organic compounds. This synergic effect causes an approximately 15 % additional reduction of the total organic carbon (TOC), representing an overall improvement of the efficiency of the mineralization of phenol. Although Fe2+ exhibits a high initial rate of degradation, the degradation is not complete due to the formation of compounds refractory to the hydroxyl radical. The interference of copper ions on the degradation of phenol by the Fenton reaction was investigated. In the presence of Cu2+, the degradation is slower, but results in a greater reduction of TOC at the end of the reaction (t = 120 min). In the final stages of the reaction, when the Fe3+ in the solution is complexed in the form of ferrioxalate, the copper ions assume the role of the main catalyst of the degradation
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Noninvasive molecular-imaging technologies are playing a keyrole in drug discovery, development and delivery. Positron Emission Tomography (PET) is such a molecular imaging technology and a powerful tool for the observation of various diseases. However, it is limited by the availability of agents with high selectivity to the target and a physical half-life of the used positron emitting nuclide which matches the biological half-life of the observed process. For the long lasting enrichment of antibodies in tumor tissue few suitable isotopes for PET imaging are currently available. The element arsenic provides a range of isotopes, which could be used for diagnosis and also for endoradiotherapy. This work describes the development of radiochemical separation procedures to separate arsenic isotopes in no-carrier-added (nca) purity from reactor or cyclotron irradiated targets, the development and evaluation of a labeling chemistry to attach these separated arsenic isotopes to monoclonal antibodies, the in vitro and in vivo evaluation of antibodies labeled with radioactive arsenic isotopes and the molecular imaging using small animal PET.
Resumo:
The proton-nucleus elastic scattering at intermediate energies is a well-established method for the investigation of the nuclear matter distribution in stable nuclei and was recently applied also for the investigation of radioactive nuclei using the method of inverse kinematics. In the current experiment, the differential cross sections for proton elastic scattering on the isotopes $^{7,9,10,11,12,14}$Be and $^8$B were measured. The experiment was performed using the fragment separator at GSI, Darmstadt to produce the radioactive beams. The main part of the experimental setup was the time projection ionization chamber IKAR which was simultaneously used as hydrogen target and a detector for the recoil protons. Auxiliary detectors for projectile tracking and isotope identification were also installed. As results from the experiment, the absolute differential cross sections d$sigma$/d$t$ as a function of the four momentum transfer $t$ were obtained. In this work the differential cross sections for elastic p-$^{12}$Be, p-$^{14}$Be and p-$^{8}$B scattering at low $t$ ($t leq$~0.05~(GeV/c)$^2$) are presented. The measured cross sections were analyzed within the Glauber multiple-scattering theory using different density parameterizations, and the nuclear matter density distributions and radii of the investigated isotopes were determined. The analysis of the differential cross section for the isotope $^{14}$Be shows that a good description of the experimental data is obtained when density distributions consisting of separate core and halo components are used. The determined {it rms} matter radius is $3.11 pm 0.04 pm 0.13$~fm. In the case of the $^{12}$Be nucleus the results showed an extended matter distribution as well. For this nucleus a matter radius of $2.82 pm 0.03 pm 0.12$~fm was determined. An interesting result is that the free $^{12}$Be nucleus behaves differently from the core of $^{14}$Be and is much more extended than it. The data were also compared with theoretical densities calculated within the FMD and the few-body models. In the case of $^{14}$Be, the calculated cross sections describe the experimental data well while, in the case of $^{12}$Be there are discrepancies in the region of high momentum transfer. Preliminary experimental results for the isotope $^8$B are also presented. An extended matter distribution was obtained (though much more compact as compared to the neutron halos). A proton halo structure was observed for the first time with the proton elastic scattering method. The deduced matter radius is $2.60pm 0.02pm 0.26$~fm. The data were compared with microscopic calculations in the frame of the FMD model and reasonable agreement was observed. The results obtained in the present analysis are in most cases consistent with the previous experimental studies of the same isotopes with different experimental methods (total interaction and reaction cross section measurements, momentum distribution measurements). For future investigation of the structure of exotic nuclei a universal detector system EXL is being developed. It will be installed at the NESR at the future FAIR facility where higher intensity beams of radioactive ions are expected. The usage of storage ring techniques provides high luminosity and low background experimental conditions. Results from the feasibility studies of the EXL detector setup, performed at the present ESR storage ring, are presented.
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This study compared the efficiency of air abrasion on enamel caries with selective enamel powder (SEP) or with alumina powder and a negative and positive control group. Ninety-three extracted molars with non-cavitated incipient enamel lesions were selected. After embedding the roots in resin, each lesion was sectioned perpendicular to the surface and photographed. Each lesion was classified microscopically as having or not having dentin involvement. The lesions were distributed into four groups with an equal number of enamel caries with or without dentin involvement. Each group was treated differently: Group 1 had SEP abrasion, Group 2 had alumina abrasion, Group 3 had sodium bicarbonate abrasion (negative control) and Group 4 had bur treatment (positive control). The surface was rephotographed after treatment. Superimposition of the photographs identified areas of "correct-excavation," "under-excavation" and "over-excavation." There were no statistical differences between lesions treated with or without dentin involvement for Groups 2 through 4. However, in the SEP group, all measured areas were significantly influenced by dentin involvement. In pairwise comparisons, no statistical differences were found between the alumina and bur groups. The SEP group, however, showed statistically significant differences for each area compared to the alumina group in enamel caries without dentin involvement. SEP performed as well as alumina and bur in lesions with dentin involvement. SEP is different in its ablative properties toward caries with dentin involvement or no dentin involvement. In terms of dental treatment, SEP seems to have a diagnostic potential for enamel lesions before operative intervention in patients with high caries risk.
Resumo:
The documented data regarding the three-dimensional structure of the air capillaries (ACs), the ultimate sites of gas exchange in the avian lung is contradictory. Further, the mode of gas exchange, described as cross-current has not been clearly elucidated. We studied the temporal and spatial arrangement of the terminal air conduits of the chicken lung and their relationship with the blood capillaries (BCs) in embryos as well as the definitive architecture in adults. Several visualization techniques that included corrosion casting, light microscopy as well as scanning and transmission electron microscopy were used. Two to six infundibulae extend from each atrium and give rise to numerous ACs that spread centrifugally. Majority of the ACs are tubular structures that give off branches, which anastomose with their neighboring cognates. Some ACs have globular shapes and a few are blind-ending tapering tubes. During inauguration, the luminal aspects of the ACs are characterized by numerous microvillus-like microplicae, which are formed during the complex processes of cell attenuation and canalization of the ACs. The parabronchial exchange BCs, initially inaugurated as disorganized meshworks, are reoriented via pillar formation to lie predominantly orthogonal to the long axes of the ACs. The remodeling of the retiform meshworks by intussusceptive angiogenesis essentially accomplishes a cross-current system at the gas exchange interface in the adults, where BCs form ring-like patterns around the ACs, thus establishing a cross-current system. Our findings clarify the mode of gas exchange in the parabronchial mantle and illuminate the basis for the functional efficiency of the avian lung.
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Time-of-flight techniques have been used to measure fast neutral CO2 products from double electron transfer reactions of CO22+ ions with 4.0–7.0 keV impact energies. Double electron transfer cross sections have been determined to be in the range of (1.1–12.5) × 10−16 cm2 for reactions of CO22+ ions with CO2, CO, N2, Ar and O2.
Differential effects of long and short carbon nanotubes on the gas-exchange region of the mouse lung
Resumo:
Abstract We hypothesise that inflammatory response and morphological characteristics of lung parenchyma differ after exposure to short or long multi-walled carbon nanotubes (MWCNT). Mice were subjected to a single dose of vehicle, short or long MWCNT by pharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) obtained at 24 h was analysed for inflammatory reaction and lung tissue was analysed for morphological alterations using stereology. Short MWCNT had stronger potential to induce polymorphonuclear cells whereas long MWCNT increased interleukin-6 levels in BALF. Alveolar septal fibrosis was only observed with short MWCNT. Type II pneumocyte hypertrophy was only detected with long MWCNT. There was no reduction in total alveolar surface area and no sign of type II cell hyperplasia. We observed mild inflammatory and pathological responses to short and long MWCNT in the lung parenchyma depending on the size of the applied MWCNT.
Resumo:
Systemic concentrations of interleukin-6 (IL-6) are elevated in patients with liver cirrhosis, and impaired hepatic uptake of IL-6 was suggested to contribute to higher levels in these patients. To test this hypothesis IL-6 was measured in portal venous serum (PVS), hepatic venous serum (HVS) and systemic venous serum (SVS) of 41 patients with liver cirrhosis and four patients with normal liver function. IL-6 was higher in PVS than HVS of all blood donors and about 43% of portal vein derived IL-6 was extracted by the healthy liver, and 6.3% by the cirrhotic liver demonstrating markedly impaired removal of IL-6 by the latter. Whereas in patients with CHILD-PUGH stage A IL-6 in HVS was almost 25% lower than in PVS, in patients with CHILD-PUGH stage C IL-6 was similarly abundant in the two blood compartments. Ascites is a common complication in cirrhotic patients and was associated with higher IL-6 levels in all blood compartments without significant differences in hepatic excretion. Hepatic venous pressure gradient did not correlate with the degree of hepatic IL-6 removal excluding hepatic shunting as the principal cause of impaired IL-6 uptake. Furthermore, patients with alcoholic liver cirrhosis had higher IL-6 in all blood compartments than patients with cryptogenic liver cirrhosis. Aetiology of liver cirrhosis did not affect hepatic removal rate indicating higher IL-6 synthesis in patients with alcoholic liver cirrhosis. In summary, the current data provide evidence that impaired hepatic removal of IL-6 is explained by hepatic shunting and liver dysfunction in patients with liver cirrhosis partly explaining higher systemic levels.