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This article presents a modified method for designing finned tube heat exchangers based on calculating the K-loss coefficients on the side tube. Besides, a CFD simulation is set up to analyse pressure drop and flow distribution on the staggered tubes. The performance of finned tube heat exchangers depends on several factors, including the number of staggered tubes, tube length, fin pitch, tube pitch, and fin area. Finned tube heat exchangers improve thermal effectiveness, particularly when dealing with gas and liquid fluids. The staggered tube arrangement complicates the prediction of pressure drop on the tube side. Also, two head pipes configure the inlet and outlet flows. The equations for determining pressure drop assume uniform velocity and constant flow distribution throughout the equipment. These correlations do not include the frictional pressure drop caused by the 180° bends welded on the tubes. In addition, equations fail to include the fluid distribution in each parallel circuit of tubes. Considering heat exchanger components as hydraulic resistances in both series and parallel configurations, an equation was developed to sum the K-loss coefficients for the tube bundle, bends, inlet pipe, and outlet pipe. From the hydraulic design results and considering that all tubes distribute water at 93 °C, the next stage consists of the thermal heat exchanger design based on the NTU method to heat air at 50 – 60 ºC. The heat exchanger design is evaluated by comparing the results with an experimental case study. This includes water flow distribution, heat transfer area, hot and cold outlet fluid temperatures, pressure drop and CFD numerical results. [ABSTRACT FROM AUTHOR]

The electrocardiogram (ECG) is an essential tool in the diagnosis of cardiovascular disease, providing valuable information about heart rhythm and function. Traditionally, physicians relied on manually identified heuristic features to detect ECG abnormalities. However, this methodology had limitations in terms of accuracy and reliability. With the aim of improving accuracy in the identification of cardiac arrhythmias, this research focused on the development of models based on convolutional neural networks. Two data sets were used: the PhysioNet MIT-BIH dataset, widely used in the scientific community, and data acquired by the Bio-Tek BP Pump NIBP arrhythmia simulator. Five models were trained with different architectures, including conventional models such as (VGG16, ResNet-50 and AlexNet), as well as two architectures proposed by the authors. All models were trained with the same number of samples and hyperparameter settings. Performance evaluation was performed using common metrics such as precision, recall, F1-score and accuracy. The results showed that the VGG16 architecture was the most effective in classifying cardiac arrhythmias, achieving an accuracy of 98.8% on the MIT-BIH dataset. Furthermore, when evaluating test data from the Bio-Tek BP Pump NIBP simulator, the customize-2 model demonstrated the best performance with an accuracy of 96.3%. These results are promising, as they demonstrate the potential of convolutional neural networks to improve accuracy in the diagnosis of cardiac arrhythmias. The models developed in this research could be a useful tool for clinicians in the early detection and appropriate treatment of these cardiovascular conditions. [ABSTRACT FROM AUTHOR]

The effect of different carbon structures on the properties of low density polyethylene film and linear low density polyethylene blends (LDPE/LLDPE) subjected to artificial weathering, was studied. The carbon structures used were carbon black (CB), multi wall carbon nanotubes (MWCNT) and Graphene nanoparticles (GNP), at various loadings: 0.05, 0.1, 0.3, 0.5, 1.0, and 2 wt%. The PE‐Carbon structure composite films were characterized by optical microscopy (MOP), Haze, visible light transmission, UV–visible, thermogravimetric analysis (TGA), melt flow determinations (MFI) and tensile properties. Weathering measurements were evaluated in a QUV panel chamber with UV fluorescent lamps. The films degradation was analyzed following the change in carbonyl index of FTIR spectra, mechanical properties, and molecular weight. A noticeable better dispersion of CB and CNT particles in polyethylene matrix was observed compared with GNP. MWCNTs and CB produced high Haze and low visible light transmission. Thermal stability measured by TGA increased with the presence of GNP and CB. The crystallinity, melting, and crystallinity temperature (Tm and Tc) of the polymers increased with MWCNT and GNP. All the films with carbon structures presented an increase in the modulus of elasticity, with CB giving the highest elastic modulus. Artificial weathering of films with carbon structures showed that CB particles and CNT provided the highest UV protection to polyethylene, with a noticeable increase in low molecular weights and a retention in tensile strength and elongation at break which was reflected in maintaining their flexibility. Films with CNT showed the least significant changes in their properties, being more resistant to photo‐degradation. [ABSTRACT FROM AUTHOR]

AbstractIn time series analysis, the decision of modeling the trend term as a stochastic or a deterministic component is a primordial step. For decades, authors have been focused on developing statistical tests to guide the analysts in such a decision. Surprisingly, less attention has been given to evaluate the robustness of the methods. This paper compares the robustness of four of the prominent tests. For this, various scenarios were used considering (i) the actual distribution of the noise term, (ii) the sample size, and (iii) the actual time series structure among auto-regressive moving average, linear structural space state, and the exponential generalize auto-regressive conditional heteroskedasticity models. An example of application on the Brazilian Gross Domestic Product is used to discuss the behavior of the methods vis-à-vis to their inferred robustness. [ABSTRACT FROM AUTHOR]

Pneumonia is a disease that has caused many deaths worldwide. Pneumonia detection methods: blood tests, sputum test, CT scan, and chest X-rays, generally require a specialist doctor for analysis. The objective of this research was to generate a model, based on semantic instances and deep learning (Mask-RCNN), that allows for support in the diagnosis of pulmonary opacities and pneumonia, using 12 024 images of chest X-ray radiographs. 3 experiments were carried out, where the conditions of the dataset images were varied (exp1: patients with pneumonia, exp2: healthy, and, also, pneumonia patients, exp3: healthy, and, also, pneumonia patients, plus data augmentation). For all 3 experiments, a histogram equalization pre-processing technique was performed. In order to evaluate the performance of the models, the parameters Intersection on the Union, Precision, Recall, F1 score, and Accuracy were used. In the identification of pulmonary opacities in the images, and for the classification of patients with pneumonia from healthy ones, Recall was found to be the best performing metric for experiment 1, for both opacity and pneumonia detection. [ABSTRACT FROM AUTHOR]

The benefits of place-based policies are still under debate. In this study, we analyze what is probably one of the boldest interventions in the recent history of Mexico and the rest of the world: the Northern Border Free Zone (NBFZ). Launched in January 2019, this program doubles the minimum wage and substantially lowers taxes in 43 municipalities along the border with the United States, aiming to improve living standards for low-wage workers and foster economic activity within the region. Given the unique features of the NBFZ, we estimate its short-run effects on labor outcomes: employment, wages, and formality. Our primary identification strategy follows a synthetic control method employing monthly administrative data at the municipality level for the period 2015–2019. Using administrative data for formal employment, we find that the policy substantially increased labor income in the NBFZ by approximately 9% over the control municipalities. The results for employment are less clear. Formal employment showed 1.6% less growth in the NBFZ than in the control municipalities, but the estimate is imprecise and we cannot reject a null impact of the program on employment. These results are robust to alternative control groups, including metropolitan areas in the United States. We also use the labor force survey to estimate the effects on formality at the individual level and find results closer to a null effect. These two results suggest that the NBFZ did not substantially affect employment, and the intersection of confidence intervals for the two estimates implies a maximum loss of employment of approximately 24,000 jobs. [ABSTRACT FROM AUTHOR]

This paper presents the solution for a fractional Bergman's minimal blood glucose-insulin model expressed by Atangana-Baleanu-Caputo fractional order derivative and fractional conformable derivative in Liouville-Caputo sense. Applying homotopy analysis method and Laplace transform with homotopy polynomial we obtain analytical approximate solutions for both derivatives. Finally, some numerical simulations are carried out for illustrating the results obtained. In addition, the calculations involved in the modified homotopy analysis transform method are simple and straightforward. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we obtain approximate‐analytical solutions of a cancer chemotherapy effect model involving fractional derivatives with exponential kernel and with general Mittag‐Leffler function. Laplace homotopy perturbation method and the modified homotopy analysis transform method were applied. The first method is based on a combination of the Laplace transform and homotopy methods, while the second method is an analytical technique based on homotopy polynomial. The cancer chemotherapy effect equations are solved numerically and analytically using the aforesaid methods. Illustrative examples are included to demonstrate the validity and applicability of the presented technique with new fractional‐order derivatives with exponential decay law and with general Mittag‐Leffler law. [ABSTRACT FROM AUTHOR]

Summary: This paper presents the analytical solutions of fractional linear electrical systems by using the Caputo‐Fabrizio fractional‐order operator in Liouville‐Caputo sense. This novel operator involves an exponential kernel without singularities. The fractional equations were solved analytically by using the properties of Laplace transform operator, as well as the convolution theorem. To validate the analytical solutions, numerical simulations were carried out. This paper presents the analytical solutions of fractional linear electrical systems by using the Caputo‐Fabrizio fractional‐order operator in Liouville‐Caputo sense. This novel operator involves an exponential kernel without singularities. The fractional equations were solved analytically by using the properties of Laplace transform operator, as well as the convolution theorem. To validate the analytical solutions, numerical simulations were carried out. [ABSTRACT FROM AUTHOR]

Graphene nanoparticles (GnPs) were modified by ethylene plasma in order to improve their compatibility with high-density polyethylene (HDPE). The role of the plasma-based surface modification on the mechanical and electrical properties of GnP/HDPE was also investigated. The surface modification of GnPs was conducted using an in-house constructed rotary plasma reactor excited by a high-voltage power source. Morphology of the GnPs before and after plasma treatment was observed by scanning electron microscopy and transmission electron microscopy. In general, GnP/HDPE composites made with GnPs treated by ethylene plasma exhibit the highest mechanical and electrical improvements. Polyethylene decreases its electrical resistivity up 6 orders of magnitude and increases its elastic modulus by ~40% with the addition of 8 wt% of GnPs treated with ethylene plasma. [ABSTRACT FROM AUTHOR]

Little information is apparently available regarding the nephrotoxic effects induced by pesticides. The aim of this study was to examine the influence of low doses of methyl parathion (MP) on the structure and function of the kidney of male Wistar rats. A corn oil (vehicle) was administered to control rats, whereas treated rats received MP at 0.56 mg/kg orally (1/25 of LD50), every third day, for 8 weeks. At the end of each week following MP exposure, creatinine and glucose levels were measured in plasma, while glucose, inorganic phosphate, total proteins, albumin, and activity of γ-glutamyltranspeptidase (GGT) were determined in urine. Kidney histological study was also performed. Compared with control rats, MP significantly increased plasma glucose and creatinine levels accompanied by decreased urinary flow rate and elevated urinary excretion rates of glucose, phosphate, and albumin. Further, the activity of GGT in urine was increased significantly. The proximal cells exhibited cytoplasmic vacuolization, positive periodic acid Schiff inclusions, and brush border edge loss after 2 or 4 weeks following MP treatment. Finally, renal cortex samples were obtained at 2, 4, 6, and 8 weeks of MP treatment, and the concentrations of reduced glutathione (GSH) and glutathione peroxidase (GPx) activity were measured. The mRNA expression levels of BAX and tumor necrosis factor-α (TNF-α) were also determined (RT-PCR). MP significantly decreased renal GSH levels, increased GPx activity, as well as downregulated the mRNA expression of TNF-α and BAX. Densitometry analysis showed a significant reduction in TNF-α and BAX mRNA expression levels at 2 and 4 weeks following MP treatment. Low doses of MP produced structural and functional damage to the proximal tubules of male rat kidney. [ABSTRACT FROM PUBLISHER]

Myxomas are the most common benign cardiac tumors, which are considered emergency surgery. The resection should not be delayed because 8-9% of affected patients may die due to intracardiac blood flow obstruction. We presente a clinical case of a 47 year old female, history of dyslipidemia. Disease starts with retrosternal oppression feeling, dyspnea on moderate exercise, dizziness, pain in joints hands. Arrhytmic heart sounds, diastolic mitral murmur II/IV, breth sounds present, no lymph. Laboratory: hemoglobin 11.0, leucocyte 9000, glucose 96 mg/dL, chest RX medium arch prominence cardiac silhouette. ECO transthoracic LVEF 60%, with left atrial intracardiac tumor 13×11 cm, pedicle fixed the interatrial septum, the mitral valve bulges, with mild mitral valve. Half sternotomy is performed intracardiac tumor resection, pericardial placement interatrial with extracorporeal circulation support 65', aortic clamping time of 40'. Intracardiac tumor surgical findings interatrial septum fixed to left side, pedicle, rounded, yellow, multiloculated, soft, 13x10 cm in diameter. Histopathological diagnosis cardiac myxoma. We conclude that the tumor resection was carried in a timely manner with satisfactory evoluction. [ABSTRACT FROM AUTHOR]

In this work we obtain analytical solutions for the electrical RLC circuit model defined with Liouville-Caputo, Caputo-Fabrizio and the new fractional derivative based in the Mittag-Leffler function. Numerical simulations of alternative models are presented for evaluating the effectiveness of these representations. Different source terms are considered in the fractional differential equations. The classical behaviors are recovered when the fractional order α is equal to 1. [ABSTRACT FROM AUTHOR]

Our objective was to obtain images of a predictable level of quality using an intraoral X-ray system with digital imaging, avoiding patient overexposure. A polymethylmethacrylate (PMMA) physical test phantom was imaged at different exposure times and at various PMMA thicknesses using a dental imaging coupled charge device. Two identical regions of interest (ROIs) were chosen in every image file, and quality was numerically evaluated by measuring high-contrast spatial resolutions, low-contrast thresholds and signal-to-noise ratios. In addition, three practitioners proposed personal quality scores by image inspection. Numerical contents in the ROIs, related to the image quality, were plotted against exposure time. From here, a simple expression linking the exposure time with the thickness to obtain images of comparable quality was deduced. As a result, the optimum exposure time for imaging with a predictable level of quality can be inferred. The potential effect could imply savings above 1000 man Sv, roughly 20 % of the collective dose due to dental imaging, over a population of 1540 millions. [ABSTRACT FROM AUTHOR]

Angiogenesis, the growth OF new capillaries from preexisting blood vessels, is a complex process involving endothelial cell (EC) activation, disruption of vascular basement membranes, and migration and proliferation of ECs. Glycan-mediated recognition has been proposed to play an instrumental role in mediating cell-cell and cell-matrix interactions. Galectins (Gal), a family of glycan-binding proteins with affinity for (ß-galactosides and a conserved sequence motif, can decipher glycan- containing information and mediate cell-cell communication. Galectin-8 (Gal-8), a member of this family, is a bivalent "tandem-repeat"-type galectin, which possesses 2 CRDs connected by a linker peptide. Here, we show that Gal-8 is endowed with proangiogeneic properties. Functional assays revealed a critical role for this lectin in the regulation of capillary-tube formation and EC migration. Moreover, Matrigel, either supplemented with Gal-8 or vascular endothelial growth factor (VEGF), injected in mice resulted in induction of in vivo angiogenesis. Remarkably, Gal-8 was expressed both in the cytoplasm and nucleus in ECs of normal and tumor vessels. Furthermore, CD 166 [activated leukocyte cell adhesion molecule (ALCAM)] was identified as a specific Gal-8-bind-ing partner in normal vascular ECs. Collectively, these data provide the first evidence demonstrating an essential role for Gal-8 in the regulation of angiogenesis with critical implications in tumor biology. [ABSTRACT FROM AUTHOR]

Copyright of Anales de Otorrinolaringología Mexicana is the property of Sociedad Mexicana de Otorrinolaringologia y Cirugia de Cabeza y Cuello and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Galectins, a family of glycan-binding proteins, influence tumor progression by modulating interactions between tumor, endothelial, stromal, and immune cells. Despite considerable progress in identifying the roles of individual galectins in tumor biology, an integrated portrait of the galectin network in different tumor microenvironments is still missing. We undertook this study to analyze the "galectin signature" of the human prostate cancer microenvironment with the overarching goal of selecting novel-molecular targets for prognostic and therapeutic purposes. In examining androgen-responsive and castration-resistant prostate cancer cells and primary tumors representing different stages of the disease, we found that galectin-1 (Gal-1) was the most abundantly expressed galectin in prostate cancer tissue and was markedly upregulated during disease progression. In contrast, all other galectins were expressed at lower levels: Gal-3, -4, -9, and -12 were downregulated during disease evolution, whereas expression of Gal-8 was unchanged. Given the prominent regulation of Gal-1 during prostate cancer progression and its predominant localization at the tumor-vascular interface, we analyzed the potential role of this endogenous lectin in prostate cancer angiogenesis. In human prostate cancer tissue arrays, Gal-1 expression correlated with the presence of blood vessels, particularly in advanced stages of the disease. Silencing Gal-1 in prostate cancer cells reduced tumor vascularization without altering expression of other angiogenesis-related genes. Collectively, our findings identify a dynamically regulated "galectin-specific signature" that accompanies disease evolution in prostate cancer, and they highlight a major role for Gal-1 as a tractable target for antiangiogenic therapy in advanced stages of the disease. [ABSTRACT FROM AUTHOR]