728 research outputs found
Equivalent layered models for functionally graded plates
Functionally graded plates whose material properties vary continuously through the thickness are modelled as exactly equivalent plates composed of up to four isotropic layers. Separate models are derived for analysis using classical plate theory, first-order and higher-order shear deformation theory. For cases where Poisson’s ratio varies through the thickness, the integrations required to obtain the membrane, coupling and out-of-plane stiffness matrices are performed accurately using a series solution. The model is verified by comparison with well converged solutions from approximate models in which the plate is divided into many isotropic layers. Critical buckling loads and undamped natural frequencies are found for a range of illustrative examples
The impact of resources on decision making
Decision making is a significant activity within industry and although much attention has been paid to the manner in which goals impact on how decision making is executed, there has been less focus on the impact decision making resources can have. This article describes an experiment that sought to provide greater insight into the impact that resources can have on how decision making is executed. Investigated variables included the experience levels of decision makers and the quality and availability of information resources. The experiment provided insights into the variety of impacts that resources can have upon decision making, manifested through the evolution of the approaches, methods, and processes used within it. The findings illustrated that there could be an impact on the decision-making process but not on the method or approach, the method and process but not the approach, or the approach, method, and process. In addition, resources were observed to have multiple impacts, which can emerge in different timescales. Given these findings, research is suggested into the development of resource-impact models that would describe the relationships existing between the decision-making activity and resources, together with the development of techniques for reasoning using these models. This would enhance the development of systems that could offer improved levels of decision support through managing the impact of resources on decision making
Three-dimensional power Doppler angiography in endometrial cancer: correlation with tumor characteristics
To assess the correlation between intratumoral vascularization using three-dimensional power Doppler angiography (3D-PDA) and several histological tumor characteristics in a series of patients with endometrial carcinoma.
METHODS:
Ninety-nine women (mean age, 61.7 (range, 31-84) years) diagnosed as having endometrial cancer were assessed by transvaginal 3D-PDA before surgical staging. Endometrial volume (EV) and 3D-PDA vascular indices (vascularization index (VI), flow index (FI) and vascularization flow index (VFI)) were calculated using the Virtual Organ Computer-aided AnaLysis (VOCAL) method. All patients were surgically staged. Individual tumor features such as histological type, tumor grade, myometrial infiltration depth, lymph-vascular space involvement, cervical involvement, lymph node metastases and tumor stage were considered for analysis. Multivariate logistic regression (MLR) analysis was used to determine which 3D-PDA parameters were independently associated with each histological characteristic.
RESULTS:
MLR analysis showed that only EV and VI were independently associated with myometrial infiltration (EV: odds ratio (OR), 1.119 (95% CI, 1.025-1.221), P = 0.012; VI: OR, 1.127 (95% CI, 1.063-1.195), P = 0.001) and tumor stage (EV: OR, 1.103 (95% CI, 1.012-1.202), P = 0.025; VI: OR, 1.120 (95% CI, 1.057-1.187), P = 0.001), only VI was independently associated with tumor grade (OR, 1.056 (95% CI, 1.023-1.091), P = 0.001) and only EV was independently associated with lymph node metastases (OR, 1.086 (95% CI, 1.017-1.161), P = 0.001).
CONCLUSION:
3D-PDA analysis of tumor vascularization in endometrial cancer correlates with some prognostic histological characteristics
Estudios térmicos sobre minerales de interés metalúrgico. V. Cinética de la descomposición térmica de crisocola y brocantita, y estudio mineralógico
The thermal decomposition process of chrysocoUa mineral and a copper hidroxysulfate is studied in this work by TGA, DTA and powder X-ray diffraction. Several data on reaction orders and activation energies valúes, as well as X-ray data are reported.Se ha estudiado el proceso de descomposición térmica de dos oxisales de cobre, una natural, crisocola, y otra sintética, brocantita, mediante termogravimetría, análisis térmico diferencial y difracción de rayos X. Se ofrecen datos sobre los valores de orden de reacción y energía de activación correspondiente a los procesos de deshidratación, así como de difractometría de polvo
Assessing myometrial infiltration by endometrial cancer: uterine virtual navigation with three-dimensional US
To describe and analyze the diagnostic performance of uterine virtual
navigation with three-dimensional (3D) ultrasonography (US) for the assessment of
the depth of myometrial infiltration by endometrial cancer. MATERIALS AND
METHODS: Institutional review board approval was obtained; patients gave oral
informed consent. Women with endometrial cancer were evaluated by using 3D US
prior to surgical staging. A 3D volume of the whole uterus was obtained and
analyzed by using software. Virtual navigation through three orthogonal planes
was performed to identify the shortest myometrial tumor-free distance to serosa
(TDS) by analyzing the lateral, anterior, posterior, and fundal portions of the
myometrium. Myometrial infiltration was also assessed by subjective impression of
an examiner. Histologic findings of myometrial infiltration and TDS measured by a
pathologist were used as the reference standard. A receiver operating
characteristic curve was plotted to identify the best cutoff for TDS for
identifying myometrial infiltration of 50% or more. RESULTS: Ninety-six women
(mean age, 61.8 years; range, 31-86 years) with endometrial cancer were included
in the study. At histologic analysis, myometrial invasion was found to be less
than 50% in 69 (72%) cases and 50% or more in 27 (28%) cases. TDS measured with
US was positively correlated with histologically measured TDS (r = 0.649; 95%
confidence interval: 0.52, 0.76). The best cutoff for US-measured TDS was 9.0 mm
(sensitivity, 100%; specificity, 61%; negative predictive value, 100%; positive
predictive value, 50%). Subjective impression had a sensitivity of 92.6%, a
specificity of 82.3%, a negative predictive value of 96.6%, and a positive
predictive value of 67.7%. CONCLUSION: Uterine virtual navigation with 3D US is a
reliable method for the assessment of myometrial infiltration in patients with
endometrial cancer
Triage for surgical management of ovarian tumors in asymptomatic women: assessment of an ultrasound-based scoring system.
OBJECTIVES:
To prospectively evaluate an ultrasound-based scoring system as a method for triaging asymptomatic women presenting with an adnexal mass for surgical treatment.
METHODS:
Two hundred and four adnexal masses in 189 asymptomatic women undergoing elective surgical treatment at our institution were included in this prospective study. Patients were evaluated by transvaginal power Doppler ultrasound imaging before surgery. Patients were classified as low risk or high risk for malignancy according to an ultrasound-based scoring system. Women with a low risk for malignancy were scheduled for laparoscopy and patients with a high risk for malignancy were scheduled for laparotomy. However, patients classified as low risk by the ultrasound scoring system, but with a tumor size >or= 10 cm or clinical suspicion of pelvic adhesions, were instead considered to be at intermediate risk and were scheduled for laparotomy. Some patients classified as high risk were scheduled for an operative laparoscopy by an expert in gynecological oncology.
RESULTS:
One hundred and thirty-four (65.7%) masses were considered to be low risk and were treated by a laparoscopically guided procedure. All these tumors were benign. Forty-seven (23%) masses were classified as high risk, of which 39 tumors were malignant and eight benign. Twenty-three (11.3%) tumors were considered to be intermediate risk and were scheduled for primary laparotomy. In this group, 21 (91.3%) tumors proved to be benign and two (8.7%) were malignant.
CONCLUSIONS:
Ultrasound-based triage of asymptomatic women diagnosed with a persistent adnexal mass is effective for selecting the surgical approach
Valorization of olive oil industry subproducts: ash and olive pomace fast pyrolysis
Environmental problems have encouraged investigation of renewable energies. The organic waste treating through fast pyrolysis seems to be a highly promising option for decreasing pollutants. Olive pomace, a major source of waste in countries with high production of olive oil (mainly Spain, Italy, and Greece), is a clear target for valorisation. Dried olive pomace together with the ashes obtained during the drying process was blended to study the influence of the inorganic metals inherently present in the ashes (K, Na, Ca and Mg) for fast pyrolysis product distribution. The results determined that these metals increased yields of phenolic compounds until a maximum was reached, whereas carboxylic acid yield fell due to the action of metals. In addition, aromatic hydrocarbons and polyphenols were obtained for those samples with a large amount of ash. Moreover, the formation of organic acids, such as acetic acid, requires a smaller proportion of ash in the blend. Finally, it has been found that the ashes could be used as a catalyst for producing better quality bio-oil, thereby avoiding extra costs and thus valorizing the industrial treatment olive pomace.Los problemas medioambientales han fomentado la investigaciĂłn de las energĂas renovables. El tratamiento de residuos orgánicos mediante pirĂłlisis rápida parece ser una opciĂłn muy prometedora para la disminuciĂłn de contaminantes. El orujo de aceituna, una fuente importante de residuos en paĂses con alta producciĂłn de aceite de oliva (principalmente España, Italia y Grecia), es un claro objetivo de valorizaciĂłn. El orujo de oliva seco junto con las cenizas obtenidas durante el proceso de secado se mezclaron para estudiar la influencia de los metales inorgánicos inherentemente presentes en las cenizas (K, Na, Ca y Mg) para una distribuciĂłn rápida del producto de pirĂłlisis. Los resultados determinaron que estos metales incrementaron los rendimientos de compuestos fenĂłlicos hasta alcanzar un máximo, mientras que el rendimiento de ácidos carboxĂlicos disminuyĂł por la acciĂłn de los metales. Además, se obtuvieron hidrocarburos aromáticos y polifenoles para aquellas muestras con gran cantidad de ceniza. Además, la formaciĂłn de ácidos orgánicos, como el ácido acĂ©tico, requiere una menor proporciĂłn de cenizas en la mezcla. Finalmente, se ha comprobado que las cenizas podrĂan utilizarse como catalizador para producir bioaceite de mejor calidad, evitando asĂ costes extras y valorizando asĂ el tratamiento industrial del orujo de oliva
"Fat but powerful'' paradox: association of muscle power and adiposity markers with all-cause mortality in older adults from the EXERNET multicentre study
Objectives: To assess the influence of muscle power and adiposity on all-cause mortality risk and to evaluate the fat but powerful'' (F+P) (or fat but fit'') paradox in older adults. Methods: A total of 2563 older adults (65 €''91 years old) from the EXERNET multicentre study were included. Adiposity (body mass index (BMI), waist circumference, body fat percentage (BF%) and fat index), allometric and relative power (sit-to-stand muscle power test) and various covariates (age, sex, hypertension, smoking status and walking and sitting times per day) were registered at baseline. All-cause mortality was recorded during a median follow-up of 8.9 years. Participants were classified into four groups: lean and powerful (L+P), F+P, lean but weak and fat and weak (F+W). Cox proportional hazard regression models and adjusted HRs were calculated. Results: According to BMI and waist circumference, all-cause mortality risk was reduced in the F+P (HR=0.55 and 0.63, p=0.044 and 0.049, respectively) and L+P (HR=0.57 and 0.58, p=0.043 and 0.025, respectively) groups. According to BF%, all-cause mortality decreased in the L+P group (HR=0.53; p=0.021), and a trend for a reduction was reported in the F+P group (HR=0.57; p=0.060). According to fat index, a survival benefit was only noted in the L+P group (HR=0.50; p=0.049). Higher levels of relative power reduced all-cause mortality risk among older people (HR=0.63 and 0.53, p=0.006 and 0.011, respectively). Conclusion: Powerful older people exhibited a reduced 9-year all-cause mortality regardless of BMI, waist circumference and BF%. Obesity according to fat index blunted the survival benefits of being powerful
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