932 resultados para Titanate, Nanofibre, Ion Exchange, Removal of Radioactive Ions, Adsorbent
Resumo:
The degradation of black dye commercial product (BDCP) composed of C.I. Disperse Blue 373, C.I. Disperse Orange 37, C.I. Disperse Violet 93 dyes was investigated by photoelectrocatalysis process. The dyes have shown high mutagenic activity with Salmonella strain YG1041 and TA98 with and without S9. Samples of BCPD dye submitted to conventional chlorination and photoelectrocatalytic oxidation were compared monitoring its products by HPLC using a diode array detector, spectrophotometry UV-vis, TOC removal, and mutagenicity potency. The photoelectrocatalytic method operating with Ti/TiO(2) as anode at +1.0 V and UV illumination presented fast oxidation of test solutions containing 10 mg L(-1) of dye in 0.1 mol L(-1) NaCl pH 4.0 leading to 100% of discoloration, 67% of mineralization, and negative response to all tested Salmonella strains. The formation of Cl(aEuro cent), CL(2) (aEuro cent) on photoelectrocatalytic medium improved the efficiency of the method in relation to conventional chlorination method that promoted 100% of discoloration, but only 8% of TOC removal and more mutagenic product.
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P-representation techniques, which have been very successful in quantum optics and in other fields, are also useful for general bosonic quantum-dynamical many-body calculations such as Bose-Einstein condensation. We introduce a representation called the gauge P representation, which greatly widens the range of tractable problems. Our treatment results in an infinite set of possible time evolution equations, depending on arbitrary gauge functions that can be optimized for a given quantum system. In some cases, previous methods can give erroneous results, due to the usual assumption of vanishing boundary conditions being invalid for those particular systems. Solutions are given to this boundary-term problem for all the cases where it is known to occur: two-photon absorption and the single-mode laser. We also provide some brief guidelines on how to apply the stochastic gauge method to other systems in general, quantify the freedom of choice in the resulting equations, and make a comparison to related recent developments.
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The electron transfer protein rubredoxin from Clostridium pasteurianum contains an Fe(S-Cys)(4) active site. Mutant proteins C9G, C9A, C42G and C42A, in which cysteine ligands are replaced by non-ligating Gly or Ala residues, have been expressed in Escherichia coli. The C42A protein expresses with a (Fe2S2)-S-III cluster in place. In contrast, the other proteins are isolated in colourless forms, although a (Fe2S2)-S-III cluster may be assembled in the C42G protein via incubation with Fe-III and sulfide. The four mutant proteins were isolated as stable mononuclear Hg-II forms which were converted to unstable mononuclear Fe-III preparations that contain both holo and apo protein. The Fe-III systems were characterized by metal analysis and mass spectrometry and by electronic, electron paramagnetic resonance, X-ray absorption and resonance Raman spectroscopies. The dominant Fe-III form in the C9A preparation is a Fe(S-Cys)(3)(OH) centre, similar to that observed previously in the C6S mutant protein. Related centres are present in the proteins NifU and IscU responsible for assembly and repair of iron-sulfur clusters in both prokaryotic and eukaryotic cells. In addition to Fe(S-Cys)(3)(OH) centres, the C9G, C42G and C42A preparations contain a second four-coordinate Fe-III form in which a ligand appears to be supplied by the protein chain. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00775-0020355-1.
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Background: One of the complications of laparoscopic adjustable gastric banding is intragastric erosion, leading to a revisional procedure to remove the band. Our aim was to present the procedure and results of endoscopic band removal in a 5-year multicenter experience from the Gastro Obeso Center and Universidade de Sao Paulo, Sao Paulo, and Universidade Federal de Pernambuco, Recite, Brazil. Methods: From 2003 to 2008, 82 patients were diagnosed with band erosion. The clinical data concerning the endoscopic procedure were prospectively recorded and retrospectively reviewed. Results: The average preoperative body mass index was 43.2 kg/m(2) (range 34-50). At the diagnosis of intragastric erosion, the body mass index was 24-41 kg/m(2) (average 31.8). The erosion occurred an average of 16.3 months (range 6-36) postoperatively. The symptoms included pain in 25 (31%), port infection in 21 patients (27%), and weight regain in 20 (25%), and 12 patients (15%) were asymptomatic. Endoscopic removal was possible for 78 patients (95%). In 85% of patients, the band was removed in the first session, with an average duration of 55 minutes (range 25-150). Five cases of pneumoperitoneum occurred after the procedure. Of these, 3 were treated conservatively, 1 was treated by laparoscopy, and I was treated by abdominal puncture using the Veress needle. Conclusion: Endoscopic removal of eroded laparoscopic adjustable gastric banding is safe and effective. It can be used as a first choice procedure in clinical practice. (Surg Obes Relat Dis 2010; 6:423-428.) (C) 2010 American Society for Metabolic and Bariatric Surgery. All rights reserved.
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Treatment of large petroclival meningiomas causing brain stem compression is surgical removal followed by radiotherapy or radiosurgery if the lesion was partially resected. The management of small petroclival meningiomas is, however, controversial. Clinical observation, radiosurgery and surgical removal are the options of treatment. The natural history of these tumours is not well known. Published series of patients treated with radiosurgery are not comparable with surgical series because the latter also includes large size tumours. In this paper we present a series of 18 patients with small petroclival meningiomas (diameter <= 2.8cm) treated with radical surgical removal. Total resection (Simpson`s Grade 1) [43] was possible with minimal morbidity and no mortality. Background. We present a series of small petroclival meningiomas (SPM) treated by radical surgical removal and compare the outcome with other management modalities proposed for these lesions. Methods. Eighteen patients with SPM were surgically treated at our department of neurological surgery. The tumours were classified as small when they had a diameter < 3.0cm. Headaches (n = 12), diplopia (n = 8), facial hypoaesthesia (n = 3) and tinnitus (n = 6) were the most frequent symptoms at presentation. The approaches used were retrosigmoid (n = 14), fronto-orbito-zygomatic (n = 3) and presigmoid (n = 1). The post-operative follow-up ranged from 1 to 110 months (mean 41.8 months). Findings. Radical tumour resection (Simpson`s Grades 1 and 2) was achieved in all patients. There was no major morbidity or mortality related to the surgical procedure. Transient abducent nerve palsy was the only post-operative complication. The pre-operative cranial nerves deficits improved after surgery. Only one patient had persistent diplopia postoperatively. Conclusion. Radical surgical removal of SPM is possible with minimal morbidity and may cure the patient. The effectiveness and outcome of surgery for small petroclival meningiomas should be compared with series treated by radiosurgery.
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Background: The use of synthetic mesh for abdominal wall closure after removal of the rectus abdominis is established but not standardised. This study compares two forms of mesh fixation: a simple suture, which fixes the mesh to the edges of the defect on the anterior rectus abdominis fascia; and total fixation, which incorporates the fasciae of the internal oblique, external oblique and transverse muscles in the suture, anchoring the mesh in the position of the removed muscle. Method: A total of 16 fresh cadavers were dissected. Two sutures were compared: simple and total. Three different sites were analysed: 5 cm above, 5 cm below and at the level of the umbilicus. The two sutures compared were tested in each region using a standardised technique. All sutures were performed with nylon 0, perpendicular to the linea alba. Each suture was secured to a dynamometer, which was pulled perpendicularly towards the midline until the rupture of the aponeurosis. `Rupture resistance` was measured in kilogram force. The mean among the groups was compared using the paired Student`s t-test to a significance level of 1% (p < 0.01). Results: The mean rupture resistance of the total suture was 160% higher than that of the simple suture. Conclusion: The total suture includes the external oblique, internal oblique and transverse fasciae, which are multi-directional, and creates a much higher resistance when compared with the simple suture. Total suture may reduce the incidence of bulging and hernias of the abdominal wall after harvesting the rectus abdominis muscle, but comparative clinical studies are necessary. (C) 2010 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Resumo:
The gene encoding the large conductance mechanosensitive ion channel (MscL) of Escherichia coli and several deletion mutants of mscL were cloned under the control of the T7 RNA polymerase promoter. Transformation of these constructs into an E. coli strain carrying an inducible T7 RNA polymerase gene allowed the specific production and labelling of MscL with [S-35]methionine. Preparation of membrane fractions of E. coli cells by sucrose gradient centrifugation indicated that the radiolabelled MscL was present in the inner cytoplasmic membrane in agreement with results of several studies. However, treatment of the labelled cells and cell membrane vesicles with various cross-linkers resulted in the majority of labelled protein migrating as a monomer with a small proportion of molecules (approximate to 25%) migrating as dimers and higher order multimers. This result is in contrast with a finding of a study suggesting that the channel exclusively forms hexamers in the cell membrane off. coli (1) and therefore may have profound implication for the activation and/or ''multimerization'' of the channel by mechanical stress exerted to the membrane. In addition, from the specific activity of the radiolabelled protein and the amount of protein in the cytoplasmic membrane fraction we estimated the number of MscL ion channels expressed under these conditions to be approximately 50 channels per single bacterium. (C) 1997 Academic Press.
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Catheter migration or catheter fracture and consequent migration of a fragment is a rare complication that occurs in 1% of the patients. Despite the low incidence, embolization may cause severe and potentially fatal complications, with the mortality rates varying between 24 and 60%. The gold standard treatment for this condition is the extraction of the fragmented catheter by the intravascular percutaneous route, through the common femoral vein. If it is not available, the extraction procedure must be performed through an alternative access. This article describes a fully successful removal of a fragmented catheter by percutaneous intravascular access obtained through the right subclavian vein.
Resumo:
Introduction: The aim of this study was to evaluate the effectiveness of different irrigant agitation techniques on smear layer removal in curved root canals. Methods: Mesiobuccal canals of 62 extracted lower molars with a curvature of 33 degrees were used and instrumented up to Pro Taper F2. The samples were divided into 3 experimental groups according to the final irrigation: conventional irrigation, ultrasonic irrigation, and sonic irrigation by using the Endo Activator system. The control group was composed of 2 specimens without any final irrigation. In all of the experimental groups, 5 mL of 17% ethylenediaminetetraacetic acid was used for 1 minute, and 5 mL of 2.5% NaOCl was used for 30 seconds. The analysis of the apical region was performed via scanning electron microscopy by 3 examiners. The data were submitted to the Kruskal-Wallis and Dunn tests (P<.05). Results: The activation systems removed significantly more smear layer than did conventional irrigation. Conclusions: Sonic and ultrasonic irrigation resulted in better removal of the smear layer in the apical third of curved root canals than did conventional irrigation. (J Endod 2011;37:1268-1271)
Resumo:
Swallowed prostheses have been described in the literature, and in some cases, the diagnosis can be challenging, especially if the partial or complete denture is metal-free. This article presents a case of a swallowed partial denture and points to the importance of early diagnosis. A man was admitted to the emergency room complaining of progressive breathing difficulty while presenting with an extra volume in his neck. After inconclusive image examinations, endoscopy under sedation was used to identify and retrieve the foreign object, which was a metal-free acrylic partial denture. Early diagnosis and the correct treatment can avoid serious sequelae, such as edematous reactions, mucosal infection, and necrosis. Patients should be scheduled for regular recall visits for evaluation of prosthesis fit and retention, condition of the abutments, and nocturnal wear. Int J Prosthodont 2010;23:339-341.
Resumo:
Introduction: This ex vivo study evaluated the heat release, time required, and cleaning efficacy of MTwo (VDW, Munich, Germany) and ProTaper Universal Retreatment systems (Dentsply/Maillefer, Ballaigues, Switzerland) and hand instrumentation in the removal of filling material. Methods: Sixty single-rooted human teeth with a single straight canal were obturated with gutta-percha and zinc oxide and eugenol-based cement and randomly allocated to 3 groups (n = 20). After 30-day storage at 37 degrees C and 100% humidity, the root fillings were removed using ProTaper UR, MTwo R, or hand files. Heat release, time required, and cleaning efficacy data were analyzed statistically (analysis of variance and the Tukey test, alpha = 0.05). Results: None of the techniques removed the root fillings completely. Filling material removal with ProTaper UR was faster but caused more heat release. Mtwo R produced less heat release than the other techniques but was the least efficient in removing gutta-percha/sealer. Conclusions: ProTaper UR and MTwo R caused the greatest and lowest temperature increase on root surface, respectively; regardless of the type of instrument, more heat was released in the cervical third. Pro Taper UR needed less time to remove fillings than MTwo R. All techniques left filling debris in the root canals. (I Endod 2010;36:1870-1873)