940 resultados para correlation coefficient analysis


Relevância:

90.00% 90.00%

Publicador:

Resumo:

This study aimed to use the plantar pressure insole for estimating the three-dimensional ground reaction force (GRF) as well as the frictional torque (T(F)) during walking. Eleven subjects, six healthy and five patients with ankle disease participated in the study while wearing pressure insoles during several walking trials on a force-plate. The plantar pressure distribution was analyzed and 10 principal components of 24 regional pressure values with the stance time percentage (STP) were considered for GRF and T(F) estimation. Both linear and non-linear approximators were used for estimating the GRF and T(F) based on two learning strategies using intra-subject and inter-subjects data. The RMS error and the correlation coefficient between the approximators and the actual patterns obtained from force-plate were calculated. Our results showed better performance for non-linear approximation especially when the STP was considered as input. The least errors were observed for vertical force (4%) and anterior-posterior force (7.3%), while the medial-lateral force (11.3%) and frictional torque (14.7%) had higher errors. The result obtained for the patients showed higher error; nevertheless, when the data of the same patient were used for learning, the results were improved and in general slight differences with healthy subjects were observed. In conclusion, this study showed that ambulatory pressure insole with data normalization, an optimal choice of inputs and a well-trained nonlinear mapping function can estimate efficiently the three-dimensional ground reaction force and frictional torque in consecutive gait cycle without requiring a force-plate.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted and geographic distribution dependent gene flow.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

BACKGROUND: Controversy exists regarding the usefulness of troponin testing for the risk stratification of patients with acute pulmonary embolism (PE). We conducted an updated systematic review and a metaanalysis of troponin-based risk stratification of normotensive patients with acute symptomatic PE. The sources of our data were publications listed in Medline and Embase from 1980 through April 2008 and a review of cited references in those publications. METHODS: We included all studies that estimated the relation between troponin levels and the incidence of all-cause mortality in normotensive patients with acute symptomatic PE. Two reviewers independently abstracted data and assessed study quality. From the literature search, 596 publications were screened. Nine studies that consisted of 1,366 normotensive patients with acute symptomatic PE were deemed eligible. Pooled results showed that elevated troponin levels were associated with a 4.26-fold increased odds of overall mortality (95% CI, 2.13 to 8.50; heterogeneity chi(2) = 12.64; degrees of freedom = 8; p = 0.125). Summary receiver operating characteristic curve analysis showed a relationship between the sensitivity and specificity of troponin levels to predict overall mortality (Spearman rank correlation coefficient = 0.68; p = 0.046). Pooled likelihood ratios (LRs) were not extreme (negative LR, 0.59 [95% CI, 0.39 to 0.88]; positive LR, 2.26 [95% CI, 1.66 to 3.07]). The Begg rank correlation method did not detect evidence of publication bias. CONCLUSIONS: The results of this metaanalysis indicate that elevated troponin levels do not adequately discern normotensive patients with acute symptomatic PE who are at high risk for death from those who are at low risk for death.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

We tested the performance of transcutaneous oxygen monitoring (TcPO2) and pulse oximetry (tcSaO2) in detecting hypoxia in critically ill neonatal and pediatric patients. In 54 patients (178 data sets) with a mean age of 2.4 years (range 1 to 19 years), arterial saturation (SaO2) ranged from 9.5 to 100%, and arterial oxygen tension (PaO2) from 16.4 to 128 mmHg. Linear correlation analysis of pulse oximetry vs measured SaO2 revealed an r value of 0.95 (p less than 0.001) with an equation of y = 21.1 + 0.749x, while PaO2 vs tcPO2 showed a correlation coefficient of r = 0.95 (p less than 0.001) with an equation of y = -1.04 + 0.876x. The mean difference between measured SaO2 and tcSaO2 was -2.74 +/- 7.69% (range +14 to - 29%) and the mean difference between PaO2 and tcPO2 was +7.43 +/- 8.57 mmHg (range -14 to +49 mmHg). Pulse oximetry was reliable at values above 65%, but was inaccurate and overestimated the arterial SaO2 at lower values. TcPO2 tended to underestimate the arterial value with increasing PaO2. Pulse oximetry had the best sensitivity to specificity ratio for hypoxia between 65 and 90% SaO2; for tcPO2 the best results were obtained between 35 and 55 mmHg PaO2.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

BACKGROUND: The diagnosis of malignant hematologic diseases has become increasingly complex during the last decade. It is based on the interpretation of results from different laboratory analyses, which range from microscopy to gene expression profiling. Recently, a method for the analysis of RNA phenotypes has been developed, the nCounter technology (Nanostring® Technologies), which allows for simultaneous quantification of hundreds of RNA molecules in biological samples. We evaluated this technique in a Swiss multi-center study on eighty-six samples from acute leukemia patients. METHODS: mRNA and protein profiles were established for normal peripheral blood and bone marrow samples. Signal intensities of the various tested antigens with surface expression were similar to those found in previously performed Affymetrix microarray analyses. Acute leukemia samples were analyzed for a set of twenty-two validated antigens and the Pearson Correlation Coefficient for nCounter and flow cytometry results was calculated. RESULTS: Highly significant values between 0.40 and 0.97 were found for the twenty-two antigens tested. A second correlation analysis performed on a per sample basis resulted in concordant results between flow cytometry and nCounter in 44-100% of the antigens tested (mean = 76%), depending on the number of blasts present in a sample, the homogeneity of the blast population, and the type of leukemia (AML or ALL). CONCLUSIONS: The nCounter technology allows for fast and easy depiction of a mRNA profile from hematologic samples. This technology has the potential to become a valuable tool for the diagnosis of acute leukemias, in addition to multi-color flow cytometry.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

BACKGROUND: Cerebral cholinergic transmission plays a key role in cognitive function, and anticholinergic drugs administered during the perioperative phase are a hypothetical cause of postoperative cognitive dysfunction (POCD). We hypothesized that a perioperative increase in serum anticholinergic activity (SAA) is associated with POCD in elderly patients. METHODS: Seventy-nine patients aged >65 years undergoing elective major surgery under stan- dardized general anesthesia (thiopental, sevoflurane, fentanyl, and atracurium) were investi- gated. Cognitive functions were assessed preoperatively and 7 days postoperatively using the extended version of the CERAD-Neuropsychological Assessment Battery. POCD was defined as a postoperative decline >1 z-score in at least 2 test variables. SAA was measured preop- eratively and 7 days postoperatively at the time of cognitive testing. Hodges-Lehmann median differences and their 95% confidence intervals were calculated for between-group comparisons. RESULTS: Of the patients who completed the study, 46% developed POCD. Patients with POCD were slightly older and less educated than patients without POCD. There were no relevant differences between patients with and without POCD regarding gender, demographically cor- rected baseline cognitive functions, and duration of anesthesia. There were no large differences between patients with and without POCD regarding SAA preoperatively (pmol/mL, median [inter- quartile range]/median difference [95% CI], P; 1.14 [0.72, 2.37] vs 1.13 [0.68, 1.68]/0.12 [−0.31, 0.57], P = 0.56), SAA 7 days postoperatively (1.32 [0.68, 2.59] vs 0.97 [0.65, 1.83]/0.25 [−0.26, 0.81], P = 0.37), or changes in SAA (0.08 [−0.50, 0.70] vs −0.02 [−0.53, 0.41]/0.1 [−0.31, 0.52], P = 0.62). There was no significant relationship between changes in SAA and changes in cognitive function (Spearman rank correlation coefficient preoperatively of 0.03 [95% CI, −0.21, 0.26] and postoperatively of −0.002 [95% CI, −0.24, 0.23]). CONCLUSIONS: In this panel of patients with low baseline SAA and clinically insignificant periopera- tive anticholinergic burden, although a relationship cannot be excluded in some patients, our analysis suggests that POCD is probably not a substantial consequence of anticholinergic medications admin- istered perioperatively but rather due to other mechanisms.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

BACKGROUND: Knowledge about determinants of quality of life (QoL) in eosinophilic oesophagitis (EoO) patients helps to identify patients at risk of experiencing poor QoL and to tailor therapeutic interventions accordingly. AIM: To evaluate the impact of symptom severity, endoscopic and histological activity on EoE-specific QoL in adult EoE patients. METHODS: Ninety-eight adult EoE patients were prospectively included (64% male, median age 39 years). Patients completed two validated instruments to assess EoE-specific QoL (EoO-QoL-A) and symptom severity (adult EoE activity index patient-reported outcome) and then underwent esophagogastroduodenoscopy with biopsy sampling. Physicians reported standardised information on EoE-associated endoscopic and histological alterations. The Spearman's rank correlation coefficient was calculated to determine the relationship between QoL and symptom severity. Linear regression and analysis of variance was used to quantify the extent to which variations in severity of EoE symptoms, endoscopic and histological findings explain variations in QoL. RESULTS: Quality of life strongly correlated with symptom severity (r = 0.610, P < 0.001). While the variation in severity of symptoms, endoscopic and histological findings alone explained 38%, 35% and 22% of the variability in EoE-related QoL, respectively, these together explained 60% of variation. Symptom severity explained 18-35% of the variation in each of the five QoL subscale scores. CONCLUSIONS: Eosinophilic oesophagitis symptom severity and biological disease activity determine QoL in adult patients with eosinophilic oesophagitis. Therefore, reduction in both eosinophilic oesophagitis symptoms as well as biological disease activity is essential for improvement of QoL in adult patients. Clinicaltrials.gov number, NCT00939263.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The aim of this thesis was to clarify willingness and suitability for entrepreneurship among students of Lappeenranta University of Technology (LUT). In addition factors that would explain academic achievement and if there were relationship between academic achievement and willingness or suitability for entrepreneurship were examined. Questionnaires were sent via e-mail to 800 students of LUT in summer 2007. Response percent was 29,6 %. Based on the collected answers factors of entrepreneurial motivation and academic achievement were analyzed using mainly Pearson’s correlation coefficient and factor analysis. In the light of these factors willingness and suitability for entrepreneurship and academic achievement were examined. The results indicated that 36,7 % of the respondents were willing and 11,4 % were suitable for entrepreneurship. The largest share of the willing ones was focused on Department of Mechanical Engineering, whereas the smallest share on Department of Environmental Technology. The largest shares of the suitable ones were on Departments of Mechanical and Electrical Engineering, and the smallest shares on Departments of Environmental, Chemical and Energy Technology. Academic achievement was affected by, among others, exercising and success in high school. Academic achievement and willingness or suitability for entrepreneurship didn’t correlate. Yet, from factors of entrepreneurial motivation internal locus of control correlated positively with academic achievement.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Ensuring the accuracy of dietary assessment instruments is paramount for interpreting diet-disease relationships. The present study assessed the relative and construct validity of the 14-point Mediterranean Diet Adherence Screener (MEDAS) used in the Prevencio´n con Dieta Mediterra´nea (PREDIMED) study, a primary prevention nutrition-intervention trial. A validated FFQ and the MEDAS were administered to 7146 participants of the PREDIMED study. The MEDASderived PREDIMED score correlated significantly with the corresponding FFQ PREDIMED score (r = 0.52; intraclass correlation coefficient = 0.51) and in the anticipated directions with the dietary intakes reported on the FFQ. Using Bland Altman"s analysis, the average MEDAS Mediterranean diet score estimate was 105% of the FFQ PREDIMED score estimate. Limits of agreement ranged between 57 and 153%. Multiple linear regression analyses revealed that a higher PREDIMED score related directly (P , 0.001) to HDL-cholesterol (HDL-C) and inversely (P , 0.038) to BMI, waist circumference, TG, the TG:HDL-C ratio, fasting glucose, and the cholesterol:HDL-C ratio. The 10-y estimated coronary artery disease risk decreased as the PREDIMED score increased (P , 0.001). The MEDAS is a valid instrument for rapid estimation of adherence to the Mediterranean diet and may be useful in clinical practice.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Ensuring the accuracy of dietary assessment instruments is paramount for interpreting diet-disease relationships. The present study assessed the relative and construct validity of the 14-point Mediterranean Diet Adherence Screener (MEDAS) used in the Prevencio´n con Dieta Mediterra´nea (PREDIMED) study, a primary prevention nutrition-intervention trial. A validated FFQ and the MEDAS were administered to 7146 participants of the PREDIMED study. The MEDASderived PREDIMED score correlated significantly with the corresponding FFQ PREDIMED score (r = 0.52; intraclass correlation coefficient = 0.51) and in the anticipated directions with the dietary intakes reported on the FFQ. Using Bland Altman"s analysis, the average MEDAS Mediterranean diet score estimate was 105% of the FFQ PREDIMED score estimate. Limits of agreement ranged between 57 and 153%. Multiple linear regression analyses revealed that a higher PREDIMED score related directly (P , 0.001) to HDL-cholesterol (HDL-C) and inversely (P , 0.038) to BMI, waist circumference, TG, the TG:HDL-C ratio, fasting glucose, and the cholesterol:HDL-C ratio. The 10-y estimated coronary artery disease risk decreased as the PREDIMED score increased (P , 0.001). The MEDAS is a valid instrument for rapid estimation of adherence to the Mediterranean diet and may be useful in clinical practice.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Large differences in reduced glutathione (GSH) levels have been found in different investigations, also in healthy people. GSH oxidation in vitro has been associated with sample acidification in the presence of oxihemoglobin. In this work, the influence of different acids on GSH determination utilizing HPLC with UV detection was evaluated. The results showed that metaphosphoric acid and sulfosalicylic acid were inadequate for analysis, because metaphosphoric acid showed to be inefficient for deproteinization and with sulfosalicylic acid loss of GSH was observed. Trichloroacetic acid did not effect GSH quantification, since the deproteinized form was immediately derivatized with 5, 5´-dithio-bis (2-nitrobenzoic) acid. Methods with TCA deproteinization presented linear results from 0.5 to 3.0 mM. The correlation coefficient between aqueous curves and GSH spiked RBC exceeded 0.99. Precision calculations showed CV lower than 10% and bias within ± 10% for concentrations of 0.5; 1.5 and 3.0 mM GSH. The recovery was higher than 94%. Moreover, GSH blood concentrations were independent of hemoglobin concentrations.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

BACKGROUND: There is a need for short, specific instruments that assess quality of life (QOL) adequately in the older adult population. The aims of the present study were to obtain evidence on the validity of the inferences that could be drawn from an instrument to measure QOL in the aging population (people 50+ years old), and to test its psychometric properties. METHODS: The instrument, WHOQOL-AGE, comprised 13 positive items, assessed on a five-point rating scale, and was administered to nationally representative samples (n = 9987) from Finland, Poland, and Spain. Cronbach's alpha was employed to assess internal consistency reliability, whereas the validity of the questionnaire was assessed by means of factor analysis, graded response model, Pearson's correlation coefficient and unpaired t-test. Normative values were calculated across countries and for different age groups. RESULTS: The satisfactory goodness-of-fit indices confirmed that the factorial structure of WHOQOL-AGE comprises two first-order factors. Cronbach's alpha was 0.88 for factor 1, and 0.84 for factor 2. Evidence supporting a global score was found with a second-order factor model, according to the goodness-of-fit indices: CFI = 0.93, TLI = 0.91, RMSEA = 0.073. Convergent validity was estimated at r = 0.75 and adequate discriminant validity was also found. Significant differences were found between healthy individuals (74.19 ± 13.21) and individuals with at least one chronic condition (64.29 ± 16.29), supporting adequate known-groups validity. CONCLUSIONS: WHOQOL-AGE has shown good psychometric properties in Finland, Poland, and Spain. Therefore, considerable support is provided to using the WHOQOL-AGE to measure QOL in older adults in these countries, and to compare the QOL of older and younger adults.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This work reports the validation of an analytical UV spectrophotometric method to assay dexamethasone in tablets (assay and dissolution studies). The method was linear in the range between 1 and 30 µg mL-1 presenting a good correlation coefficient (r = 0.9998, n = 7). Precision and accuracy analysis showed low relative standard deviation (< 2.00%) and good percentual recoveries (95-105%). The procedure was linear, accurate, precise, and robust. The method is simple, and it has low cost. It does not use polluting reagents and can be applied in dissolution studies, being an adequate alternative to assay dexamethasone in tablets.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This work reports the validation of an analytical UV spectrophotometric method to assay acyclovir in hydrophilic matrices (assay and dissolution studies). The method was linear in the range between 2.5-20 µg mL-1, presenting a good correlation coefficient ( r = 0,9999). Precision and accuracy analysis showed low relative standart deviation (< 2.0 %) and a good recoveries percentual (98.9-100 %). The procedure was linear, accurate, and robust. The method is simple and cheap. It does not use polluting reagents and can be applied in dissolution studies, being an adequate alternative to assay acyclovir in hydrophilic matrices tablets.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Adapalene is a retinoid drug often used for disorders of the skin, mainly acne. In this work, an analytical method for the quantification of adapaleno in suspensions of nanocapsules by HPLC was developed and validated. The method was linear in the range of 10-30 µg mL-1, with a good correlation coefficient (r = 0.994). Precision and accuracy analysis showed low relative standard deviation (< 4.6%) and a good recovery percentual (98.2-106.9%). The procedure was specific, linear, precise, exact and robust so that the method can be applied in quantification of adapalene in suspensions of nanocapsules.