A Novel Topology Optimization Approach for Flow Power Loss Minimization Across Fin Arrays

Fin arrays are widely utilized in many engineering applications, such as heat exchangers and micro-post reactors, for higher level of fluid–solid contacts. However, high fluid pressure loss is reportedly the major drawback of fin arrays and a challenge for pumping supply, particularly at micro-scales. Previous studies also indicate that fin shapes, spacing and alignment play an important role on the overall pressure losses. Therefore, we present a numerical tool to minimize pressure losses, considering the geometrical aspects related to fin arrays. In this regard, a density-based topology optimization approach is developed based on the pseudo-spectral scheme and Brinkman penalization in 2D periodic domains. Discrete sensitives are derived analytically and computed at relatively low cost using a factorization technique. We study different test cases to demonstrate the flexibility, robustness and accuracy of the present tool. In-line and staggered arrays are considered at various Reynolds numbers and fluid–solid volume fractions. The optimal topologies interestingly indicate a pressure loss reduction of nearly compared to circular fins. In passive optimization test examples, the added solid parts reduced pressure loss of a circular fin ( ) by eliminating the flow separation and filling the wake region

Thermodynamics phase transition of Anti de Sitter Schwarzschild scalar-tensor-vector-Black Holes

Instead of scalar tensor gravity models which is applicable for description of cosmic inflation with unknown dark sector of matter/energy, at presentense there are presented different alternative scalar tensor vector gravities where meaningful dynamical vector fields can support cosmic inflation well without to use dark matter/energy concept. One of these gravity models was presented by Moffat which its modified Schwarzschild black hole solution is used to study thermodynamic phase transition in presence of the AdS space pressure in this article. To do so we obtained an equation of state which asymptotically reaches to equation of state of ideal gas for large black holes but for small scale black holes we obtained a critical point at phase space where the black hole can be exhibit with a phase transition at processes of isotherm and isobaric. By looking at diagrams of the Gibbs free energy and the heat capacity at constant pressure which are plotted versus the temperature and the specific volume one can see an inflection point which means that the phase transition is type of second order. In fact there is small to large phase transition for the black hole which is equivalent to the Van der Waals liquid-gas phase transition in ordinary thermodynamic systems. The phase transition is happened below the critical point in phase space when the gravitational charge of the black hole is equal to its mass.Comment: 21 pages, 4 figure

Refractive errors in infants with retinopathy of prematurity treated using laser or anti-vascular endothelial growth factor monotherapy

Background: Infants treated for retinopathy of prematurity (ROP) could develop visually significant refractive errors. In this study, we report pre-treatment refractive errors in premature infants with treatment-requiring ROP treated using laser or anti-VEGF monotherapy and compare the components of post-treatment refractive error values between the two treatment groups at different follow-up timepoints. Methods: In this retrospective cohort study, we analyzed 360 eyes of 181 premature infants with treatment-requiring ROP who were referred to Farabi Eye Hospital, Tehran, Iran between March 2020 and April 2021. Of the 360 eyes, 195 received laser monotherapy (laser treatment group) and 165 received an intravitreal anti-VEGF injection (anti-VEGF therapy group). All included eyes underwent pre- and post-treatment cycloplegic refraction. Cycloplegia was induced for each infant by instilling a mixed eye drop containing 1% tropicamide, 2.5% phenylephrine, and 0.5% tetracaine (in equal volumes) in each eye three times at five-minute intervals. Cycloplegic refraction was performed 30 minutes after the third instillation. Results: The mean (standard deviation [SD]) gestational age (GA) and birth weight (BW) of the infants were 29.0 (2.0) weeks and 1241.0 (403.0) g, respectively. The male-to-female ratio in the entire study cohort was 107 (59.1%) / 74 (40.9%), whereas the ratios in the anti-VEGF therapy group and laser treatment group were 47 (56.6%) / 36 (43.4%) and 60 (61.2%) / 38 (38.8%), respectively. The pre-treatment assessment revealed that 218 (60.6%) eyes were hyperopic, 112 (31.1%) were myopic, and 30 (8.3%) were emmetropic. In the anti-VEGF therapy group, 87 (52.7%) eyes were hyperopic, 63 (38.2%) were myopic, and 15 (9.1%) were emmetropic. In the laser treatment group, 131 (67.2%) eyes were hyperopic, 49 (25.1%) were myopic, and 15 (7.7%) were emmetropic. The mean (SD) spherical refractive error and spherical equivalent of refractive error (SEQ) at the 1-week, 1-month, and > 6-month post-treatment follow-up timepoints; the mean cylindrical refractive error at the 3-month post-treatment timepoint; and the mean SEQ at the time of ROP regression were significantly different between the treatment groups (all P < 0.05). The rate of anisometropia increased significantly from 3.4% at baseline to 9.2% at the 6-month post-treatment follow-up timepoint (P < 0.05). Conclusions: In this study, the most common pre-treatment refractive status of all included eyes with treatment-requiring ROP and eyes in each treatment group was hyperopia, followed by myopia and emmetropia. At the more than 6-month post-treatment follow-up, cycloplegic refraction revealed that the laser-treated eyes were significantly more hyperopic than the anti-VEGF-treated eyes, a finding similar to the pre-treatment refraction results. Further studies of same cohort with a longer follow-up period and a control group are needed to determine the real-world effect of each treatment modality on the refractive statuses of children treated for ROP

Serum Level of Vitamin D and Febrile Seizure? A Clinical Study

Objective:To evaluate the serum level of vitamin D in children aged six to 60 months with febrile seizure and febrile children without the seizureMaterials & MethodsFebrile children aged six to 60 months with or without seizure were studied. Demographic characteristics, serum level of vitamin D, and other laboratory findings were recorded.ResultsAmong the 104 children, 51 patients had fever without a seizure and 53 patients had a febrile seizure. The mean subjects’ age was significantly more in the febrile seizure group compared to the without seizure group (16.26 ± 11.87 versus 26.36 ± 14.11 months, p = 0.001). The mean serum level of vitamin D in the with and withouts eizure groups was 41.92 ± 22.42 and 48.41 ± 15.25 microgram perd eciliter, respectively (p = 0.08). There was no significant correlation between serum level of vitamin D and seizure occurrence (p = 0.07).The mean serum sodium and potassium levels, and platelet count were significantly lower in the febrile seizure group compared to the without seizure group (p < 0.05). There were no significant differences between the two groups regarding hemoglobin, blood sugar, creatinine, blood urea nitrogen, calcium, alkaline phosphatase levels, and white blood cell count (p > 0.05).ConclusionThe serum level of vitamin D in febrile children with or without seizure was normal. The serum level of vitamin D was lower inp atients with the seizure but not statistically significant. More clinical studies are needed to evaluate the relationship between febrile seizurea nd the serum level of vitamin D

Spontaneous Adrenal Hematoma in a Pregnant Woman; a Case Report

Spontaneous adrenal hematoma is a very rare condition and its prevalence has been reported to be about 1% in previous studies. Although various causes have been proposed to explain its incidence in existing case reports, the etiology and pathology of this condition is still not known. The present study presents a case of spontaneous adrenal hematoma in a pregnant 31 year old woman without history of trauma or other probable risk factors of hemorrhage, presenting to the emergency department with chief complaint of pain in the right flank. Diagnostic measures, imaging and laparotomy, confirmed the diagnosis of spontaneous adrenal hematoma for her

Aflatoxin M1 contamination levels in cheeses sold in Isfahan Province, Iran

Objectives: Aflatoxin M1 (AFM1)-contaminated dairy products pose serious human health risks, causing liver and renal failure if consumed. They are also related to decreased milk and egg production in infected animals. This study investigated the AFM1 contamination levels in cheeses sold in Isfahan province, Iran, by enzyme-linked immunosorbent assay (ELISA). Methods: A total of 100 white cheese samples were randomly collected from supermarkets in Isfahan province and after extraction using dichloromethane were prepared for the ELISA. Results: Of the 100 samples, 52 (52%) were contaminated by AFM1, at levels ranging from 50.2 to 424.4 ng/kg. The remaining 48% of the samples had undetectable AFM1 levels (< 50 ng/ kg). Based on the standard limit set by the European Commission and Iran, 8% (8/100) of the AFM1-positive samples (with concentrations between 250.2 and 424.4 ng/kg) had levels higher than the permissible value of 250 ng/kg. Conclusion: Although the percentage of cheese samples in Isfahan province with AFM1 levels exceeding the national permissible limit was low, the examination of cheeses and the milk used for their production is nevertheless important for ensuring public health. Furthermore, optimum storage conditions of animal feed should be ensured, and livestock nutrition must be monitored for the presence of AFM1 and other aflatoxins

Encapsulation of orange peel oil in biopolymeric nanocomposites to control its release under different conditions

Orange peel oil (OPO) is one of the most common flavorings used in the food industry, but it is volatile under environmental conditions (the presence of light, oxygen, humidity, and high temperatures). Encapsulation by biopolymer nanocomposites is a suitable and novel strategy to improve the bioavailability and stability of OPO and its controlled release. In this study, we investigated the release profile of OPO from freeze-dried optimized nanocomposite powders as a function of pH (3, 7, 11) and temperature (30, 60, and 90 °C), and within a simulated salivary system. Finally, its release kinetics modelling was performed using experimental models. The encapsulation efficiency of OPO within the powders, along with the morphology and size of the particles, were also evaluated by an atomic force microscopy (AFM) analysis. The results showed that the encapsulation efficiency was in the range of 70–88%, and the nanoscale size of the particles was confirmed by AFM. The release profile showed that the lowest and the highest release rates were observed at the temperatures of 30 and 90 °C and in the pH values of 3 and 11, respectively, for all three samples. The Higuchi model provided the best model fitting of the experimental data for the OPO release of all the samples. In general, the OPO encapsulates prepared in this study showed promising characteristics for food flavoring applications. These results suggest that the encapsulation of OPO may be useful for controlling its flavor release under different conditions and during cooking

The bioinformatics study of the interactions between microRNAs and genes involved in relapse of breast cancer treated with tamoxifen

Background and Objective: Tamoxifen is the most commonly used treatment for the patients with breast cancer called ER +, which prevents the expression of genes that are effective in the growth and proliferation of cancer cells by estrogen. Resistant to Tamoxifen is a major clinical problem in breast cancer treatment. In recent studies, the role of microRNAs in tamoxifen resistance has been raised through the influence of regulation of cell cycle control genes. Throughout this study, the interactions of microRNAs with genes involved in tamoxifen resistance were investigated. Materials and Methods: By comparing the gene expression data in samples of patients sensitive and resistant to Tamoxifen from the GEO database and searching in the database of articles, genes and microRNAs with significant expression variations were determined. Then, by examining the correlation between the expression of genes and microRNAs and bioinformatics by mirwalk software, the interconnection network between the genes and microRNAs was drawn. Results: The results showed that 21 genes and 62 microRNAs altered in Tamoxifen resistant specimens. With miR342-3P/5P targeting the HOXB13, PRM2, and KLK3 genes, and MiR-520h and miR-582-5p microRNAs, targeting 5 reduced expression genes, can lead to recurrence of breast cancer. Conclusion: The regulatory network mapped out between a set of genes and microRNAs that are potentially involved in the recurrence of breast cancer treated with Tamoxifen could clarify the role of the microRNAs in the recurrence of breast cancer. © 2018, Zanjan University of Medical Sciences and Health Services. All rights reserved