967 resultados para SQUARE RESONATORS
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Objective: To evaluate patients with Diabetes Mellitus type 2 and painful peripheral neuropathy in order to investigate oral complaints and facial somatosensory findings. Research design and methods: Case-control study; 29 patients (12 women, mean age 57.86 yo) with Diabetes Mellitus type 2 and 31 age-gender-matched controls were evaluated with a standardized protocol for general characteristics, orofacial pain, research diagnostic criteria for temporomandibular disorders, visual analogue scale and McGill Pain questionnaire, and a systematic protocol of quantitative sensory testing for bilateral facial sensitivity at the areas innervated by the trigeminal branches, which included the thermal detection by ThermoSensi 2, tactile evaluation with vonFrey filaments, and superficial pain thresholds with a superficial algometer (Micromar). Statistical analysis was performed with Wilcoxon, chi-square, confidence intervals and Spearman (p < 0.05). Results: Orofacial pain was reported by 55.2% of patients, and the most common descriptor was fatigue (50%); 17.2% had burning mouth. Myofascial temporomandibular disorders were diagnosed in 9(31%) patients. The study group showed higher sensory thresholds of pain at the right maxillary branch (p = 0.017) but sensorial differences were not associated with pain (p = 0.608). Glycemia and HbA(1c) were positively correlated with the quantitative sensory testing results of pain (p < 0.05) and cold (p = 0.044) perceptions. Higher pain thresholds were correlated with higher glycemia and glycated hemoglobin (p = 0.027 and p = 0.026). Conclusions: There was a high prevalence of orofacial pain and burning mouth was the most common complaint. The association of loss of pain sensation and higher glycemia and glycated hemoglobin can be of clinical use for the follow-up of DM complications. (C) 2010 Elsevier Ltd. All rights reserved.
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Background: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. Methods: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values <= 0.05. Discriminatory performance was evaluated by a binary logistic regression model. Results: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 +/- 2 mu V; 8 +/- 9 mu V; p < 0.001) and peak TWA values (26 +/- 13 mu V; 37 +/- 20 mu V; p = 0,009) as well as on baseline TWA heart rate (79 +/- 10 bpm; 67 +/- 15 bpm; p < 0.001) and peak TWA heart rate (118 +/- 8 bpm; 90 +/- 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. Conclusions: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols. Ann Noninvasive Electrocardiol 2009;14(2):108-118.
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Background and objectives: As well as being a marker of body iron stores, serum ferritin (sFerritin) has also been shown to be a marker of inflammation in hemodialysis (HD) patients. The aim of this study was to analyze whether sFerritin is a reliable marker of the iron stores present in bone marrow of HD patients. Design: Histomorphometric analysis of stored transiliac bone biopsies was used to assess iron stores by determining the number of iron-stained cells per square millimeter of bone marrow. Results: In 96 patients, the laboratory parameters were hemoglobin = 11.3 +/- 1.6 g/dl, hematocrit = 34.3 +/- 5%, sFerritin 609 +/- 305 ng/ml, transferrin saturation = 32.7 +/- 22.5%, and C-reactive protein (CRP) = 0.9 +/- 1.4 mg/dl. sFerritin correlated significantly with CRP, bone marrow iron, and time on HD treatment W = 0.006, 0.001, and 0.048, respectively). The independent determinants of sFerritin were CRP (beta-coef = 0.26; 95% CI = 24.6 to 132.3) and bone marrow iron (beta-coef = 0.32; 95% CI = 0.54 to 2.09). Bone marrow iron was higher in patients with sFerritin >500 ng/ml than in those with sFerritin :5500 ng/ml. In the group of patients with sFerritin :5500 ng/ml, the independent determinant of sFerritin was bone marrow iron (beta-coef = 0.48, 95% CI = 0.48 to 1.78), but in the group of patients with sFerritin >500 ng/ml, no independent determinant of sFerritin was found. Conclusions: sFerritin adequately reflects iron stores in bone marrow of HD patients.
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Two new macropolycyclic hexaamines L(2) and L(4) as their copper(II) complexes have been isolated as products from the condensation of the diamino-substituted macrocyclic complex trans-(6,13-dimethyl-1,4,8,11-tetraazacyclo-tetradecane-6,13-diamine)copper(II) [CuL(1)](2+) with aqueous formaldehyde. Both of the complexes exhibit methylene bridges between the pendant amine and the adjacent co-ordinated macrocyclic N-donors. Their crystal structures have been determined: [CuL(2)(NCS)][SCN], triclinic, space group P (1) over bar, a = 7.133(2), b = 9.813(2), c = 16.745(3) Angstrom, alpha = 101.05(2), beta = 99.36(2), gamma = 99.77(2)degrees, Z = 2; [CuL(4)Cl][ClO4]. H2O, triclinic, space group P (1) over bar, a = 9.3327(8), b = 10.8989(6), c = 12.672(1) Angstrom, alpha = 68.591(6), beta = 78.899(6), gamma = 87.384(6)degrees, Z = 2. The complexes exhibit square-pyramidal geometries, and significantly lower-energy electronic maxima relative to their parent complex [CuL(1)](2+). Electrochemistry of [CuL(2)](2+) revealed a reversible Cu-II-Cu-I redox couple, by contrast to those of macromonocyclic analogues.
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Aortic valve calcium (AVC) can be quantified on the same computed tomographic scan as coronary artery calcium (CAC). Although CAC is an established predictor of cardiovascular events, limited evidence is available for an independent predictive value for AVC. We studied a cohort of 8,401 asymptomatic subjects (mean age 53 10 years, 69% men), who were free of known coronary heart disease and were undergoing electron beam computed tomography for assessment of subclinical atherosclerosis. The patients were followed for a median of 5 years (range 1 to 7) for the occurrence of mortality from any cause. Multivariate Cox regression models were developed to predict all-cause mortality according to the presence of AVC. A total of 517 patients (6%) had AVC on electron beam computed tomography. During follow-up, 124 patients died (1.5%), for an overall survival rate of 96.1% and 98.7% for those with and without AVC, respectively (hazard ratio 3.39, 95% confidence interval 2.09 to 5.49). After adjustment for age, gender, hypertension, dyslipidemia, diabetes mellitus, smoking, and a family history of premature coronary heart disease, AVC remained a significant predictor of mortality (hazard ratio 1.82, 95% confidence interval 1.11 to 2.98). Likelihood ratio chi-square statistics demonstrated that the addition of AVC contributed significantly to the prediction of mortality in a model adjusted for traditional risk factors (chi-square = 5.03, p = 0.03) as well as traditional risk factors plus the presence of CAC (chi-square = 3.58, p = 0.05). In conclusion, AVC was associated with increased all-cause mortality, independent of the traditional risk factors and the presence of CAC. (C) 2010 Published by Elsevier Inc. (Am J Cardiol 2010;106:1787-1791)
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To date very Few families of critical sets for latin squares are known. The only previously known method for constructing critical sets involves taking a critical set which is known to satisfy certain strong initial conditions and using a doubling construction. This construction can be applied to the known critical sets in back circulant latin squares of even order. However, the doubling construction cannot be applied to critical sets in back circulant latin squares of odd order. In this paper a family of critical sets is identified for latin squares which are the product of the latin square of order 2 with a back circulant latin square of odd order. The proof that each element of the critical set is an essential part of the reconstruction process relies on the proof of the existence of a large number of latin interchanges.
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Viability and functional results of a segment replantation depend on the prevention of deleterious effects of ischemia. Prolonged ischemia leads to alterations in the microcirculation: thrombosis, edema, production of oxygen free radicals, and platelet aggregation. The effect of IIb-IIIa glycoprotein inhibitors was tested in a partial limb amputation model submitted to warm ischemia. The male Wistar rats were divided into four groups: G1 with 0 hours of ischemia and saline (n = 20), G2 with 6 hours of ischemia and saline (n = 24), G3 with 6 hours of ischemia and abciximab (n = 23), and G4 with 6 hours of ischemia and tirofiban (n = 29). The limbs were observed for 7 days and classified as viable or nonviable. Viability, and mortality rates were obtained and analyzed by Q-square and Fisher exact tests (p < 0.05). The viability rates were 100% (G1), 30% (G2), 77.78% (G3), and 80.95% (G4). G2 was statistically different from G1, G3, and G4. G1, G3, and G4 were not statistically different. Transoperative and postoperative mortalities were not statistically different. The administration of abciximab and tirofiban improved limb salvage after ischemia and reperfusion and did not modify mortality rates significantly.
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Gold(III)-directed condensation of ethane-1,2-diamine with nitroethane and formaldehyde yielded the gold-coloured macrocyclic complex (cis-6,13-dimethyl-6,13-dinitro-1,4,8,11-tetraazacyclotetradecan-1-ido)gold(III) and the orange acyclic complex (1,9-diamino-5-methyl-5-nitro-3,7-diazanoran-3-ido)gold(III) in good yields. Dissolution in strongly acidic solution gave the colourless fully protonated complexes. The pendant nitro groups are disposed on the same side of the macrocycle in a cis geometry, as confirmed by crystal structure analysis. In both complexes the gold ion lies in a square-planar environment of four nitrogen donors, and the co-ordinate bond to the deprotonated amine is shorter than the remaining Au-N distances.
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Obesity is associated with increased sympathetic activity and higher mortality. Treatment of this condition is often frustrating. Roux-en-Y gastric bypass is the most effective technique nowadays for treatment of obesity. The aim of the present study is to assess the effects of this surgery on the cardiac autonomic activity, including the influence of gender and age, through heart rate variability (HRV) analysis. The study group consisted of 71 obese patients undergoing gastric bypass. Time domain measures of HRV, obtained from 24-h Holter recordings, were evaluated before and 6 months after surgery, and the results were compared. Percentage of interval differences of successive normal sinus beats greater than 50 ms (pNN50) and square root of the mean squared differences of successive normal sinus beat intervals (rMSSD) was used to estimate the short-term components of HRV, related to the parasympathetic activity. Standard deviation of intervals between all normal sinus beats (SDNN) was related to overall HRV. SDNN, pNN50, and rMSSD showed significant increase 6 months after surgery (p < 0.001, p = 0.001 and p = 0.002, respectively). Men presented a greater increase of SDNN than women (p = 0.006) during the follow-up. There was a difference in rMSSD evolution for age groups (p = 0.002). Only younger patients presented significant increase of rMSSD. Overall HRV increased 6 months after surgery; this increase was more evident in men. Cardiac parasympathetic activity increased also, but in younger patients only.
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Fluid mixing in steady and unsteady Bow through a channel containing periodic square obstructions has been studied using a finite-difference simulation to determine fluid velocities, followed by the use of passive marker particle advection to look at fluid transport out of the cavities formed between each of the obstructions. The geometry and Bow conditions were chosen from the work by Perkins (1989, M.S. Thesis, Lehigh University; 1992, Ph.D. Thesis, Lehigh University); who investigated heat transfer enhancement due to unsteady flow through such an obstructed channel. Particle advection shows that Bow regimes which are predicted to give good mixing based on snapshots of instantaneous streamline contour plots were not necessarily able to efficiently mix fluid which started in the cavity regions throughout the channel. The use of Poincare sections shows regular regions existing under these conditions which inhibit efficient fluid transport. These regular regions are found to disappear when the unsteady Bow velocity is increased. (C) 1997 Elsevier Science Ltd.
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Conducting dielectric samples are often used in high-resolution experiments at high held. It is shown that significant amplitude and phase distortions of the RF magnetic field may result from perturbations caused by such samples. Theoretical analyses demonstrate the spatial variation of the RF field amplitude and phase across the sample, and comparisons of the effect are made for a variety of sample properties and operating field strengths. Although the effect is highly nonlinear, it tends to increase with increasing field strength, permittivity, conductivity, and sample size. There are cases, however, in which increasing the conductivity of the sample improves the homogeneity of the amplitude of the RF field across the sample at the expense of distorted RF phase. It is important that the perturbation effects be calculated for the experimental conditions used, as they have the potential to reduce the signal-to-noise ratio of NMR experiments and may increase the generation of spurious coherences. The effect of RF-coil geometry on the coherences is also modeled, with the use of homogeneous resonators such as the birdcage design being preferred, Recommendations are made concerning methods of reducing sample-induced perturbations. Experimental high-field imaging and high-resolution studies demonstrate the effect. (C) 1997 Academic Press.
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Background: This pilot study evaluates the association of severe periodontitis with pulse wave velocity (PWV), carotid artery intima-medial thickness (IMT), and clinical, metabolic, and atherogenic inflammatory markers in 79 subjects with heterozygous familial hypercholesterolemia (hFH). All subjects were free of previous vascular disease manifestations. Methods: The body mass index (in kilograms per square meter), plasma lipids, glucose, C-reactive protein, and white blood cell counts were evaluated. After full-mouth periodontal examinations, patients were categorized into the severe periodontitis group (SPG) or non-severe periodontitis group (NSPG). Results: The SPG showed significantly higher values of cholesterol-year scores, triglycerides, glucose, PWV, IMT, and diastolic blood pressure (DBP) (P <= 0.05) than the NSPG. After adjustment for traditional risk factors for atherosclerosis, only the association between severe periodontitis and DBP (odds ratio: 3.1; 95% CI: 1.1 to 8.5; P = 0.03) was confirmed. Conclusion: In individuals with hFH, severe periodontitis was associated with a higher DBP, which suggests that severe periodontitis, itself, may contribute to the increased cardiovascular risk profile in this population. J Periodontol 2011;82:683-688.
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Objectives: To describe clinical, radiological findings, and outcome in a multiethnic population of stroke survivors with basilar artery occlusive disease (BAOC). Methods: Forty patients with infarcts in the basilar artery (BA) territory, alive 30 days after the ictus, participated in the study. BA stenosis (>50%) or occlusion was shown by magnetic resonance or digital subtraction angiography in all patients. Demographical, clinical and radiological characteristics were described. Modified Rankin Scale (MRS) scores at 30 days and 6 months after the ischemic event were evaluated. Association between demographical, clinical, radiological features and outcome were analyzed with Chi-square and Fisher`s exact tests. MRS scores at 30 days and 6 months were compared with the Wilcoxon test. Results: Sixty percent of the patients were men, and 33% were Afro-Brazilian. Mean age was 55.8 +/- 12.9 years. Most (90%) had multiple vascular risk factors. Stroke was preceded by TIA in 48% of the patients, and 80% had a history of arterial hypertension. The most common neurological symptom was vertigo/dizziness (60%) and the sign, hemiparesis (60%). Most of the infarcts were located in the pons (85%) and the BA middle third was the most frequently affected segment (33%). BA occlusion occurred in 58% of the patients. More severe vascular occlusive lesions were present in Whites (p = 0.002) and in patients with involvement of the middle third of the BA (p = 0.021). Large-artery atherosclerosis was the most common stroke etiology (88%) and was more frequent in older patients (p < 0.001). Most patients were treated with anticoagulation. MRS scores improved significantly at 6 months (p < 0.001): at this time, 78% of the patients had MRS scores between 0 and 2. Conclusions: We observed different results compared with other series: greater proportion of Afro-descendents, higher frequency of atherosclerosis and BA occlusion. Rates of preceding TIAs and good outcome at 6 months were similar to previously published data. These results represent a step forward towards understanding BAOC in a multiethnic context. (C) 2009 Elsevier B.V. All rights reserved.
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Background. The am of this study was to determine the predictive value for malignancy of microcalcifications determined by ultrasonography in thyroid nodules. Methods. One hundred seventy-seven nodules were prospectively studied by ultrasonography and compared with their fine-needle aspirative biopsy. The association between the presence and type of calcification and cytologic findings was verified through the chi-square test or likelihood ratio. Results. Thirty nodules showed calcification, of which 17 had fine calcifications, 3 had fine and gross calcifications, and 10 had only coarse calcification. Seven (41.18%) of 17 fine calcified nodules were malignant on cytology, 8 (47.06%) were benign, 1 (5,88%) was indeterminate, and 1 was suspect for malignancy. We found statistical significance between the presence of fine calcifications and malignancy (p =.001) and, in the 13 malignant nodule group, 8 (61.50%) had fine calcifications. Conclusion. This study suggests that microcalcifications were highly specific for malignancy and were present in 61% of the malignant nodules. (c) 2008 Wiley Periodicals, Inc.
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The reaction of the bis(1,2-diamine) copper(II) complexes of racemic propane-1,2-diamine (pn) and 2-methylpropane-1,2-diamine (dmen) with formaldehyde and nitroethane in methanol under basic conditions yields minor macrocyclic condensation products in addition to the major acyclic products. Where C-pendant methyl groups on the pair of coordinated diamines are in cis dispositions, the first -NH-CH2-C(CH3)(NO2)-CH2-NH- ring formation occurs at amine pairs distant from these C-methyl substituents, and further reaction to yield a macrocycle is not observed. However, where the C-methyl substituents are in trans dispositions, the chemistry proceeds to yield the macrocycle. Commencing with pn, trans-(6,13-diammonio-2,6,9,13-tetramethyl-1,4,7,10-tetraazacyclotetradecane)copper(II) perchlorate formed and crystallized in the space group P2(1)/n, with a 9.782(2), b 9.2794(6), c 17.017(4) Angstrom, beta 103.24(1)degrees. The copper ion is found in a square-planar environment, with the two methyl groups of the pn residues and the pairs of introduced pendant groups all in trans arrangements.