979 resultados para Photochemical fixation
Resumo:
Basilar invagination (BI) is a congenital craniocervical junction (CCJ) anomaly represented by a prolapsed spine into the skull-base that can result in severe neurological impairment. In this paper, we retrospective evaluate the surgical treatment of 26 patients surgically treated for symptomatic BI. BI was classified according to instability and neural abnormalities findings. Clinical outcome was evaluated using the Nürick grade system. A total of 26 patients were included in this paper. Their age ranged from 15 to 67 years old (mean 38). Of which, 10 patients were male (38%) and 16 (62%) were female. All patients had some degree of tonsillar herniation, with 25 patients treated with foramen magnum decompression. Nine patients required a craniocervical fixation. Six patients had undergone prior surgery and required a new surgical procedure for progression of neurological symptoms associated with new compression or instability. Most of patients with neurological symptoms secondary to brainstem compression had some improvement during the follow-up. There was mortality in this series, 1 month after surgery, associated with a late removal of the tracheal cannula. Management of BI requires can provide improvements in neurological outcomes, but requires analysis of the neural and bony anatomy of the CCJ, as well as occult instability. The complexity and heterogeneous presentation requires attention to occult instability on examination and attention to airway problems secondary to concomitant facial malformations.
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This work assessed the environmental impacts of the production and use of 1 MJ of hydrous ethanol (E100) in Brazil in prospective scenarios (2020-2030), considering the deployment of technologies currently under development and better agricultural practices. The life cycle assessment technique was employed using the CML method for the life cycle impact assessment and the Monte Carlo method for the uncertainty analysis. Abiotic depletion, global warming, human toxicity, ecotoxicity, photochemical oxidation, acidification, and eutrophication were the environmental impacts categories analyzed. Results indicate that the proposed improvements (especially no-til farming-scenarios s2 and s4) would lead to environmental benefits in prospective scenarios compared to the current ethanol production (scenario s0). Combined first and second generation ethanol production (scenarios s3 and s4) would require less agricultural land but would not perform better than the projected first generation ethanol, although the uncertainties are relatively high. The best use of 1 ha of sugar cane was also assessed, considering the displacement of the conventional products by ethanol and electricity. No-til practices combined with the production of first generation ethanol and electricity (scenario s2) would lead to the largest mitigation effects for global warming and abiotic depletion. For the remaining categories, emissions would not be mitigated with the utilization of the sugar cane products. However, this conclusion is sensitive to the displaced electricity sources.
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Paper has become increasingly recognized as a very interesting substrate for the construction of microfluidic devices, with potential application in a variety of areas, including health diagnosis, environmental monitoring, immunoassays and food safety. The aim of this review is to present a short history of analytical systems constructed from paper, summarize the main advantages and disadvantages of fabrication techniques, exploit alternative methods of detection such as colorimetric, electrochemical, photoelectrochemical, chemiluminescence and electrochemiluminescence, as well as to take a closer look at the novel achievements in the field of bioanalysis published during the last 2 years. Finally, the future trends for production of such devices are discussed.
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The aim of this study was to evaluate the differential sensitivity of sugarcane genotypes to H2O2 in root medium. As a hypothesis, the drought tolerant genotype would be able to minimize the oxidative damage and maintain the water transport from roots to shoots, reducing the negative effects on photosynthesis. The sugarcane genotypes IACSP94-2094 (drought tolerant) and IACSP94-2101 (drought sensitive) were grown in a growth chamber and exposed to three levels of H2O2 in nutrient solution: control; 3mmolL(-1) and 80mmolL(-1). Leaf gas exchange, photochemical activity, root hydraulic conductance (Lr) and antioxidant metabolism in both roots and leaves were evaluated after 15min of treatment with H2O2. Although, root hydraulic conductance, stomatal aperture, apparent electron transport rate and instantaneous carboxylation efficiency have been reduced by H2O2 in both genotypes, IACSP94-2094 presented higher values of those variables as compared to IACSP94-2101. There was a significant genotypic variation in relation to the physiological responses of sugarcane to increasing H2O2 in root tissues, being root changes associated with modifications in plant shoots. IACSP94-2094 presented a root antioxidant system more effective against H2O2 in root medium, regardless H2O2 concentration. Under low H2O2 concentration, water transport and leaf gas exchange of IACSP94-2094 were less affected as compared to IACSP94-2101. Under high H2O2 concentration, the lower sensitivity of IACSP94-2094 was associated with increases in superoxide dismutase activity in roots and leaves and increases in catalase activity in roots. In conclusion, we propose a general model of sugarcane reaction to H2O2, linking root and shoot physiological responses.
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The aim of this study was to evaluate the microscopic structure and chemical composition of titanium bone plates and screws retrieved from patients with a clinical indication and to relate the results to the clinical conditions associated with the removal of these devices. Osteosynthesis plates and screws retrieved from 30 patients between January 2010 and September 2013 were studied by metallographic, gas, and energy dispersive X-ray (EDX) analyses and the medical records of these patients were reviewed. Forty-eight plates and 238 screws were retrieved. The time elapsed between plate and screw insertion and removal ranged between 11 days and 10 years. Metallographic analysis revealed that all the plates were manufactured from commercially pure titanium (CP-Ti). The screw samples analyzed consisted of Ti-6Al-4V alloy, except four samples, which consisted of CP-Ti. Titanium plates studied by EDX analysis presented greater than 99.7% titanium by mass. On gas analysis of Ti-6Al-4V screws, three samples were outside the standard values. One CP-Ti screw sample and one plate sample also presented an oxygen analysis value above the standard. The results indicated that the physical properties and chemical compositions of the plates and screws did not correspond with the need to remove these devices or the time of retention.
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Ofloxacin is an antimicrobial agent frequently found in significant concentrations in wastewater and surface water. Its continuous introduction into the environment is a potential risk to non-target organisms or to human health. In this study, ofloxacin degradation by UV/TiO2 and UV/TiO2/H2O2, antimicrobial activity (E. coli) of samples subjected to these processes, and by-products formed were evaluated. For UV/TiO2, the degradation efficiency was 89.3% in 60 min of reaction when 128 mg L(-1) TiO2 were used. The addition of 1.68 mmol L(-1) hydrogen peroxide increased degradation to 97.8%. For UV/TiO2, increasing the catalyst concentration from 4 to 128 mg L(-1) led to an increase in degradation efficiency. For both processes, the antimicrobial activity was considerably reduced throughout the reaction time. The structures of two by-products are presented: m/z 291 (9-fluoro-3-methyl-10-(methyleneamino)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid) and m/z 157 ((Z)-2-formyl-3-((2-oxoethyl)imino)propanoic acid).
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The purpose of this study is to introduce a method to evaluate visual functions in infants in the first three months of life. An adaptation of the Guide for the Assessment of Visual Ability in Infants (Gagliardo, 1997) was used. The instrument was a ring with string. It was implemented a pilot study with 33 infants, selected according to the following criteria: neonates well enough to go home within two days of birth; 1 to 3 months of chronological age; monthly evaluation with no absence; subjects living in Campinas/SP metropolitan area. In the first month we observed: visual fixation (93,9%); eye contact (90,9%); horizontal tracking (72,7%); inspects surroundings (97,0%). In the third month, we observed: inspects own hands (42,4%) and increased movements of arms (36,4%). This method allowed the evaluation of visual functions in infants, according to the chronological age. Alterations in this function will facilitate immediate referral to medical services for diagnoses.
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Carotenoids are widely distributed in nature, providing yellow, orange or red color in a great number of vegetables, microorganisms and in some animals. Carotenoids act as biological antioxidants and seem to play an important role in human health by protecting cells and tissues from the damaging effects of free radicals and singlet oxygen. Several authors describe the oxidative cleavage of carotenoids in flavor compounds as occuring through chemical or photochemical degradations or through biotechnological processes. Biotransformation of carotenoids seems to be a reasonable alternative to produce flavor compounds since these compounds are considered 'natural' ingredients. In this work we describe the properties of some carotenoids, as well as biotechnological approaches to obtain its oxyfunctionalized derivatives.
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The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction
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Purpose: To study the effects of pupillary constriction on frequency doubling perimetry in a group of normal subjects. Methods: Eighteen healthy volunteers participated in the study. Only one eye per patient (right eye) underwent frequency doubling perimetry (Full Threshold C-20 strategy). For the second session, one drop of 2% pilocarpine was administered to the volunteers' right eye and the examination was repeated after 60 minutes. Results: Sixty minutes after administration of 2% pilocarpine, there was a significant reduction of the pupillary diameter from 4.22 ± 0.17 mm to 1.55 ± 0.51 mm (p<0.05). There was a significant reduction of the mean retinal sensibility after pupillary constriction. The threshold sensitivity of the central 5º worsened by 5.67 ± 2.49 dB; the area between 2.5º and 10º worsened by 4.49 ± 2.73 dB; and the area between 10º and 20º worsened by 5.10 ± 3.55 dB (p<0.01). A reduction of 4.06 ± 2.67 dB was observed in the mean deviation, as well as an increase of 0.64 ± 0.94 dB in the pattern standard deviation (p<0.01). No differences were observed regarding the number of fixation losses, false-positive and false-negatives responses, and duration of the examination. Conclusion: Changes in pupillary diameter may produce significant declines in threshold sensitivities of the 20º visual field tested by frequency doubling perimetry. These results suggest that is important to maintain a constant pupillary diameter in seriate examinations.
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The cerebral cysticercosis can produce intracranial hypertension by inflammatory obstruction of the basal cysterns or by expansive lesion in the cerebral parenchima or ventricular cavities. In the latter and in tumor cases the clinical picture is very similar and only after surgery can the etiology be determined. We present 11 operated cases of intracranial cysticercosis which presented the clinical picture of an expansive lesion. There were 7 females and 4 males with ages between 4 and 65 years. Nine patients were admitted because of headache, vomiting and visual disturbances suggestive of intracranial hypertension. One patient was admited with lymphocytic meningitis and another with focal seizures following hemiparesis. Five patients presented focal signs and six edema of the papilla. Epileptic manifestations were present in 45.5% of the cases. A plain X-ray films of the skull failed to reveal calcificatons, however signs of chronic hypertension were present in three cases. The electroencephalogram showed slow focal waves in 8 patients The spinal fluid examination revealed lymphocytosis in 4 cases, increased protein content in another 4 and complement fixation for cysticercosis was positive in 2 cases. The expansive lesions were localized by angiograph and ventriculography. In these the location was temporal in 4, frontal in 3, parietal in 2, in the third ventricle in one and in the fourth ventricle in another. At surgery we removed a large cyst from the cerebral parenchyma in six cases. Around the cyst a thick glial reaction was present. In the other cases the cyst was small but fixed to the ventricular trigone and produced dilatation of the inferior horn of the lateral ventricle. In two cases we removed a solitary intraventricular cyst from the third and fourth ventricles. In the two children operated upon there were several small hard cysts involving the cerebral parenchyma which displayed intense gliosis. There were no postoperative complications.
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A case of brain abscess and meningitis due to pigmented fungi is reported. The patient was a 59-year-old white male, who had enjoyed excellent health until October 1977, when he developed headache, later accompanied by paresthesias and weakness in the left-sided extremities. These symptoms worsened progressively and in November of that year he had to quit his job. From February 1978 on he became inactive and anorexic. Intense continuous headache was associated with frequent episodes of vomiting. He gradually became tor-porous, and according to his relatives, suffered from visual and possibly auditory deficiency. On examination, he was malnourished and dehydrated, with decubitus ulcers. Temperature was 38,5°C. A left-sided spastic hemiplegia and prominent meningorradicular signs were noted. The CSF was examined six times between May 17th and June 1st and showed variable hypercytosis (143 to 4,437 leucocytes/ cu mm) with predominance of neutrophils (up tp 95%), low glucose and high protein concentrations. No microorganisms were identified. Electroencephalographic study disclosed a low background activity especially in left temporal areas. Despite supportive care and antibiotic therapy he lapsed into coma. Carotid angiography was normal on June 1st. He remained in deep coma until his death on June 6th, 1978. Necropsy was limited to the brain, which weighed 1,550 g after fixation and showed diffuse intense edema and hyperemia. On coronal sectioning an encapsulated abscess was found in the right basal ganglia, which also involved the internal capsule, and measured 1.5 cm in diameter. Microscopical examination disclosed large numbers of brownish fungi, appearing both as oval yeasts and as septate hyphae in the thick fibrous capsule and in the necrotic content of the abscess. The same organisms were demonstrated in moderate numbers in the leptomeninges of the medulla oblongata and , less frequently, of the hippo-campal region and cerebellum.
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The biological fixation between the dental implant surfaces and jaw bones should be considered a prerequisite for the long-term success of implant-supported prostheses. In this context, the implant surface modifications gained an important and decisive place in implant research over the last years. As the most investigated topic in, it aided the development of enhanced dental treatment modalities and the expansion of dental implant use. Nowadays, a large number of implant types with a great variety of surface properties and other features are commercially available and have to be treated with caution. Although surface modifications have been shown to enhance osseointegration at early implantation times, for example, the clinician should look for research evidence before selecting a dental implant for a specific use. This paper reviews the literature on dental implant surfaces by assessing in vitro and in vivo studies to show the current perspective of implant development. The review comprises quantitative and qualitative results on the analysis of bone-implant interface using micro and nano implant surface topographies. Furthermore, the perspective of incorporating biomimetic molecules (e.g.: peptides and bone morphogenetic proteins) to the implant surface and their effects on bone formation and remodeling around implants are discussed.
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Edible films are thin materials based on biopolymers and food additives. The aim of this work is a review on the application of dynamic mechanical analysis in edible film technology. After a brief review of the linear visco-elasticity theory, a description of some practical aspects related to dynamic mechanical analysis, such as sample fixation and sample dehydration during analysis and types and modes of tests are presented. Thus, the use of temperature scanning analysis for glass transition and for plasticizer-biopolymer compatibility studies and frequency scanning tests, less common in edible film technology, are critically reviewed.
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This paper examines the role of parent rock, pedogenetic processes and airborne pollution in heavy metal accumulation in soils from a remote oceanic island, Fernando de Noronha, Brazil. We studied five soil profiles developed from different volcanic rocks. Mineralogical composition and total concentrations of major and trace elements were determined in 43 samples. The obtained concentrations range for heavy metals were: Co: 26-261 ppm; Cu: 35-97 ppm; Cr: 350-1446 ppm; Ni: 114-691 ppm; Zn: 101-374 ppm; Hg: 2-150 ppb. The composition of soils is strongly affected by the geochemical character of the parent rock. Pedogenesis appears to be responsible for the accumulation of Zn, Co, and, to a lesser extent, of Ni and Cu, in the upper, Mn- and organic carbon-enriched horizons of the soil profiles. Pedogenic influence may also explain the relationship observed between Cr and the Fe. Hg is likely to have been added to the soil profile by long-range atmospheric transport. Its accumulation in the topsoil was further favoured by the formation of stable complexes with organic matter. Clay minerals do not appear to play an important role in the fixation of heavy metals.