996 resultados para optical-lattice potential
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Purpose. To investigate misalignments (MAs) on retinal nerve fiber layer thickness (RNFLT) measurements obtained with Cirrus(©) SD-OCT. Methods. This was a retrospective, observational, cross-sectional study. Twenty-seven healthy and 29 glaucomatous eyes of 56 individuals with one normal exam and another showing MA were included. MAs were defined as an improper alignment of vertical vessels in the en face image. MAs were classified in complete MA (CMA) and partial MA (PMA), according to their site: 1 (superior, outside the measurement ring (MR)), 2 (superior, within MR), 3 (inferior, within MR), and 4 (inferior, outside MR). We compared RNFLT measurements of aligned versus misaligned exams in all 4 sectors, in the superior area (sectors 1 + 2), inferior area (sectors 3 + 4), and within the measurement ring (sectors 2 + 3). Results. RNFLT measurements at 12 clock-hour of eyes with MAs in the superior area (sectors 1 + 2) were significantly lower than those obtained in the same eyes without MAs (P = 0.043). No significant difference was found in other areas (sectors 1 + 2 + 3 + 4, sectors 3 + 4, and sectors 2 + 3). Conclusion. SD-OCT scans with superior MAs may present lower superior RNFLT measurements compared to aligned exams.
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An HPLC-PAD method using a gold working electrode and a triple-potential waveform was developed for the simultaneous determination of streptomycin and dihydrostreptomycin in veterinary drugs. Glucose was used as the internal standard, and the triple-potential waveform was optimized using a factorial and a central composite design. The optimum potentials were as follows: amperometric detection, E1=-0.15V; cleaning potential, E2=+0.85V; and reactivation of the electrode surface, E3=-0.65V. For the separation of the aminoglycosides and the internal standard of glucose, a CarboPac™ PA1 anion exchange column was used together with a mobile phase consisting of a 0.070 mol L(-1) sodium hydroxide solution in the isocratic elution mode with a flow rate of 0.8 mL min(-1). The method was validated and applied to the determination of streptomycin and dihydrostreptomycin in veterinary formulations (injection, suspension and ointment) without any previous sample pretreatment, except for the ointments, for which a liquid-liquid extraction was required before HPLC-PAD analysis. The method showed adequate selectivity, with an accuracy of 98-107% and a precision of less than 3.9%.
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The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60 mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test. CFTR gene sequencing can identify CFTR mutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-III CFTR mutations (10 patients) (G1), CF patients with classes IV-VI CFTR mutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis, χ(2), and Fisher's exact tests, α = 0.05. No differences were observed between the CF patients and healthy controls for the PDMax, Δamiloride, and Δchloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-III CFTR mutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects.
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Rubus niveus Thunb. plant belongs to Rosaceae family and have been used traditionally to treat wounds, burns, inflammation, dysentery, diarrhea and for curing excessive bleeding during menstrual cycle. The present study was undertaken to investigate the in vivo genotoxicity of Rubus niveus aerial parts extract and its possible chemoprotection on doxorubicin (DXR)-induced DNA damage. In parallel, the main phytochemicals constituents in the extract were determined. The animals were exposed to the extract for 24 and 48h, and the doses selected were 500, 1000 and 2000mg/kg b.w. administered by gavage alone or prior to DXR (30mg/kg b.w.) administered by intraperitoneal injection. The endpoints analyzed were DNA damage in bone marrow and peripheral blood cells assessed by the alkaline alkaline (pH>13) comet assay and bone marrow micronucleus test. The results of chemical analysis of the extract showed the presence of tormentic acid, stigmasterol, quercitinglucoronide (miquelianin) and niga-ichigoside F1 as main compounds. Both cytogenetic endpoints analyzed showed that there were no statistically significant differences (p>0.05) between the negative control and the treated groups with the two higher doses of Rubus niveus extract alone, demonstrating absence of genotoxic and mutagenic effects. Aneugenic/clastogenic effect was observed only at 2000mg/kg dose. On the other hand, in the both assays and all tested doses were observed a significant reduction of DNA damage and chromosomal aberrations in all groups co-treated with DXR and extract compared to those which received only DXR. These results indicate that Rubus niveus aerial parts extract did not revealed any genotoxic effect, but presented some aneugenic/clastogenic effect at higher dose; and suggest that it could be a potential adjuvant against development of second malignant neoplasms caused by the cancer chemotherapic DXR.
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Phosphatases have long been regarded as tumor suppressors, however there is emerging evidence for a tumor initiating role for some phosphatases in several forms of cancer. Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP; acid phosphatase 1 [ACP1]) is an 18 kDa enzyme that influences the phosphorylation of signaling pathway mediators involved in cancer and is thus postulated to be a tumor-promoting enzyme, but neither unequivocal clinical evidence nor convincing mechanistic actions for a role of LMWPTP have been identified. In the present study, we show that LMWPTP expression is not only significantly increased in colorectal cancer (CRC), but also follows a step-wise increase in different levels of dysplasia. Chemical inhibition of LMWPTP significantly reduces CRC growth. Furthermore, downregulation of LMWPTP in CRC leads to a reduced migration ability in both 2D- and 3D-migration assays, and sensitizes tumor cells to the chemotherapeutic agent 5-FU. In conclusion, this study shows that LMWPTP is not only overexpressed in colorectal cancer, but it is correlated with the malignant potential of this cancer, suggesting that this phosphatase may act as a predictive biomaker of CRC stage and represents a rational novel target in the treatment of this disease.
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To evaluate p16(INK) (4a) immunoexpression in CIN1 lesions looking for differences between cases that progress to CIN2/3 maintain CIN1 diagnosis, or spontaneously regress. Seventy-four CIN1 biopsies were studied. In the follow-up, a second biopsy was performed and 28.7% showed no lesion (regression), 37.9% maintained CIN1, and 33.4% progressed to CIN2/3. Immunostaining for p16(INK) (4a) was performed in the first biopsy and it was considered positive when there was strong and diffuse staining of the basal and parabasal layers. Pearson's chi-square was used to compare the groups (p ≤ 0.05). The age of the patients was similar. There was no significant difference in p16(INK) (4a) immunoexpression in the groups, however, statistical analyses showed a significant association when only the progression and regression groups were compared (p = 0.042). Considering p16(INK) (4a) positivity and the progression to CIN2/3, the sensitivity, specificity, positive, and negative predictive values in our cohort were 45%, 75%, 47%, and 94%, respectively. We emphasize that CIN1 with p16(INK) (4a) staining was associated with lesion progression, but the sensitivity was not high. However, the negative predictive value was more reliable (94%) and p16(INK) (4a) may represent a useful biomarker that can identify CIN1 lesions that need particular attention, complementing morphology.
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MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.
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This work investigated the cytotoxic and genotoxic potential of water from the River Paraíba do Sul (Brazil) using Allium cepa roots. An anatomo-morphological parameter (root length), mitotic indices, and frequency of micronuclei were analysed. Eight bulbs were chosen at random for treatment for 24 to 120 hours with the River water collected in the years of 2005 and 2006 from sites in the cities of Tremembé and Aparecida (São Paulo state, Brazil). Daily measurements of the length of the roots grown from each bulb were carried out throughout the experiment. Mitotic index (MI) and frequency of micronuclei (MN) were determined for 2000 cells per root, using 3-5 root tips from other bulbs (7-10). Only in the roots treated with samples of the River water collected in 2005 in Tremembé city was there a decrease in the root length growth compared to the respective control. However, a reduction in MI values was verified for both sites analysed for that year. Considering the data involving root length growth and especially MI values, a cytotoxic potential is suggested for the water of the River Paraíba do Sul at Tremembé and Aparecida, in the year of 2005. On the other hand, since in this year the MN frequency was not affected with the river water treatments, genotoxicity is not assumed for the river water sampled at the aforementioned places.
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PURPOSE: To verify perceptions and conduct of students with visual impairment regarding devices and equipment utilized in schooling process. METHODS: A transversal descriptive study on a population of 12-year-old or older students in schooling process, affected by congenital or acquired visual impairment, inserted in the government teaching system of Campinas during the year 2000. An interview quiz, created based on an exploratory study was applied. RESULTS: A group of 26 students, 46% of them with low vision and 53.8% affected by blindness was obtained. Most of the students were from fundamental teaching courses (65.4%), studying in schools with classrooms provided with devices (73.1%). Among the resources used in reading and writing activities, 94.1% of the students reported they used the Braille system and 81.8% reported that the reading subject was dictated by a colleague. Most of the students with low vision wore glasses (91.7%), and 33.3% utilized a magnifying glass as optical devices. Among the non-optical devices, the most common were the environmental ones, getting closer to the blackboard (75.0%) and to the window (66.7%) for better lighting. CONCLUSIONS: It became evident that students with low vision eye-sight made use of devices meant for bearers of blindness, such as applying the Braille system. A reduced number of low vision students making use of optical and non-optical devices applicable to their problems were observed, indicating a probable unawareness of their visual potential and the appropriate devices to improve efficiency.
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With the increase in life expectancy, biomaterials have become an increasingly important focus of research because they are used to replace parts and functions of the human body, thus contributing to improved quality of life. In the development of new biomaterials, the Ti-15Mo alloy is particularly significant. In this study, the Ti-15Mo alloy was produced using an arc-melting furnace and then characterized by density, X-ray diffraction, optical microscopy, hardness and dynamic elasticity modulus measurements, and cytotoxicity tests. The microstructure was obtained with β predominance. Microhardness, elasticity modulus, and cytotoxicity testing results showed that this material has great potential for use as biomaterial, mainly in orthopedic applications.
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Contents of proteins, carbohydrates and oil of seeds of 57 individuals of Vochysiaceae, involving one species of Callisthene, six of Qualea, one of Salvertia and eight of Vochysia were determined. The main nutritional reserves of Vochysiaceae seeds are proteins (20% in average) and oils (21. 6%). Mean of carbohydrate contents was 5. 8%. Callisthene showed the lowest protein content (16. 9%), while Q. cordata was the species with the highest content (30% in average). The contents of ethanol soluble carbohydrates were much higher than those of water soluble carbohydrates. Oil contents lay above 20% for most species (30. 4% in V. pygmaea and V. pyramidalis seeds). The predominant fatty acids are lauric (Q. grandiflora), oleic (Qualea and Salvertia) or acids with longer carbon chains (Salvertia and a group of Vochysia species). The distribution of Vochysiaceae fatty acids suggests for seeds of some species an exploitation as food sources (predominance of oleic acid), for other species an alternative to cocoa butter (high contents or predominance of stearic acid) or the production of lubricants, surfactants, detergents, cosmetics and plastic (predominance of acids with C20 or C22 chains) or biodiesel (predominance of monounsaturated acids). The possibility of exploitation of Vochysiaceae products in a cultivation regimen and in extractive reserves is discussed.
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The aim of this study was to look for evidence of allelochemicals in B. decumbens, in parts of the plant from where they could easily be released to the environment. The germination inhibition of Phalaris canariensis, Lactuca sativa (standard species) and Melinis minutiflora, another invasive African grass, was tested using B. decumbens germinating seeds and aqueous leachates of the roots, green and senescent leaves, at 5, 10 and 20% w/v. Both the germinating seeds and the aqueous leachates of B. decumbens reduced the germination of the species tested; the effectiveness of the aqueous leachates increased according to concentration. Apparently, the competitive advantage of B. decumbens in the cerrados could be amplified via allelopathy.
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We have considered a Bose gas in an anisotropic potential. Applying the the Gross-Pitaevskii Equation (GPE) for a confined dilute atomic gas, we have used the methods of optimized perturbation theory and self-similar root approximants, to obtain an analytical formula for the critical number of particles as a function of the anisotropy parameter for the potential. The spectrum of the GPE is also discussed.
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PURPOSE: To evaluate an experimental animal model to study the abdominal tissue activity considering its interaction with a polypropylene mesh, through the use of one of the optical phenomena of light Laser, the biospeckle. METHODS: Fifty Wistar male rats were divided into four groups: Group 1: ten animals not submitted to surgery; Group 2: ten animals submitted to surgery without polypropylene mesh; Group 3: 20 animals submitted to surgery followed by the mesh placement; Group 4: (sham) with ten animals. None of the animals presented post surgical complications being submitted to the optical tests at the 20th postoperative day. RESULTS: The analysis from the biospeckle tests, comparing the medians and standard deviations with T Student test, indicated that no significative difference was observed on the abdominal wall tissue activity in the four groups considered, with and without polypropylene mesh prosthesis implantation. CONCLUSION: The animal model is viable and the biospeckle open ways for a great number of experiments to be developed in evaluating tissue activity.