Search results for: pulsatile blood flow

Authors: Sourabh Jain, Vikas Jain, Dharmendar Kumar

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The present study investigated the antidiabetic potential of Cedrus deodara heart wood aqueous extract. Aqueous extract of Cedrus deodara was found to reduce blood sugar level in alloxan induced diabetic rats. Reduction in blood sugar could be seen from 5th day after continuous administration of the extract and on 21st day sugar levels were found to be reduced by 40.20%. Oxidative stress produced by alloxan was found to be significantly lowered by the administration of Cedrus deodara aqueous extract (500 mg/kg). This was evident from a significant decrease in lipid per oxidation level in liver induced by alloxan. The level of Glutathione, Catalase, Superoxide dismutase and Glutathione-S-Transferase in liver, kidney and pancreas tissue were found to be increased significantly after drug administration. The results obtained in the present study suggest that the Cedrus deodara aqueous extract effectively and significantly reduced the oxidative stress induced by alloxan and produced a reduction in blood sugar level.

Keywords: Cedrus deodara, heartwood, antioxidant, anti-diabetic, anti-inflammatory

Procedia PDF Downloads 381

Authors: Tuqa Abdulrazzaq, Hussein Togun, M. K. A. Ariffin, S. N. Kazi, A. Badarudin, N. M. Adam, S. Masuri

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Numerical study of heat transfer and fluid flow over vertical double forward facing step were presented. The k-w model with finite volume method was employed to solve continuity, momentum, and energy equations. Different step heights were adopted for range of Reynolds number varied from 10000 to 40000, and range of temperature varied from 310K to 340 K. The straight side of duct is insulated while the side of double forward facing step is heated. The result shows augmentation of heat transfer due to the recirculation region created after and before steps. Effect of step length and Reynolds number observed on increase of local Nusselt number particularly at recirculation regions. Contour of streamline velocity is plotted to show recirculation regions after and before steps. Numerical simulation in this paper done by used ANSYS Fluent 14.

Keywords: turbulent flow, double forward, heat transfer, separation flow

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Authors: Machimontorn Promtong, Sherman C. P. Cheung, Guan H. Yeoh, Sara Vahaji, Jiyuan Tu

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The wide range of industrial applications involved with boiling flows promotes the necessity of establishing fundamental knowledge in boiling flow phenomena. For this purpose, a number of experimental and numerical researches have been performed to elucidate the underlying physics of this flow. In this paper, the improved wall boiling models, implemented on ANSYS CFX 14.5, were introduced to study subcooled boiling flow at elevated pressure. At the heated wall boundary, the Fractal model, Force balance approach and Mechanistic frequency model are given for predicting the nucleation site density, bubble departure diameter, and bubble departure frequency. The presented wall heat flux partitioning closures were modified to consider the influence of bubble sliding along the wall before the lift-off, which usually happens in the flow boiling. The simulation was performed based on the Two-fluid model, where the standard k-ω SST model was selected for turbulence modelling. Existing experimental data at around 5 bars were chosen to evaluate the accuracy of the presented mechanistic approach. The void fraction and Interfacial Area Concentration (IAC) are in good agreement with the experimental data. However, the predicted bubble velocity and Sauter Mean Diameter (SMD) are over-predicted. This over-prediction may be caused by consideration of only dispersed and spherical bubbles in the simulations. In the future work, the important physical mechanisms of bubbles, such as merging and shrinking during sliding on the heated wall will be incorporated into this mechanistic model to enhance its capability for a wider range of flow prediction.

Keywords: subcooled boiling flow, computational fluid dynamics (CFD), mechanistic approach, two-fluid model

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Authors: Yu-Jia Jian, Emily Chia-Yu Su, Hui-Ling Hsu, Jian-Jhih Chen

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Coronary artery is the major supplier of myocardial blood flow. When fat and cholesterol are deposit in the coronary arterial wall, narrowing and stenosis of the artery occurs, which may lead to myocardial ischemia and eventually infarction. According to the World Health Organization (WHO), estimated 740 million people have died of coronary heart disease in 2015. According to Statistics from Ministry of Health and Welfare in Taiwan, heart disease (except for hypertensive diseases) ranked the second among the top 10 causes of death from 2013 to 2016, and it still shows a growing trend. According to American Heart Association (AHA), the risk factors for coronary heart disease including: age (> 65 years), sex (men to women with 2:1 ratio), obesity, diabetes, hypertension, hyperlipidemia, smoking, family history, lack of exercise and more. We have collected a dataset of 421 patients from a hospital located in northern Taiwan who received coronary computed tomography (CT) angiography. There were 300 males (71.26%) and 121 females (28.74%), with age ranging from 24 to 92 years, and a mean age of 56.3 years. Prior to coronary CT angiography, basic data of the patients, including age, gender, obesity index (BMI), diastolic blood pressure, systolic blood pressure, diabetes, hypertension, hyperlipidemia, smoking, family history of coronary heart disease and exercise habits, were collected and used as input variables. The output variable of the prediction module is the degree of coronary artery stenosis. The output variable of the prediction module is the narrow constriction of the coronary artery. In this study, the dataset was randomly divided into 80% as training set and 20% as test set. Four machine learning algorithms, including logistic regression, stepwise regression, neural network and decision tree, were incorporated to generate prediction results. We used area under curve (AUC) / accuracy (Acc.) to compare the four models, the best model is neural network, followed by stepwise logistic regression, decision tree, and logistic regression, with 0.68 / 79 %, 0.68 / 74%, 0.65 / 78%, and 0.65 / 74%, respectively. Sensitivity of neural network was 27.3%, specificity was 90.8%, stepwise Logistic regression sensitivity was 18.2%, specificity was 92.3%, decision tree sensitivity was 13.6%, specificity was 100%, logistic regression sensitivity was 27.3%, specificity 89.2%. From the result of this study, we hope to improve the accuracy by improving the module parameters or other methods in the future and we hope to solve the problem of low sensitivity by adjusting the imbalanced proportion of positive and negative data.

Keywords: decision support, computed tomography, coronary artery, machine learning

Procedia PDF Downloads 224

Authors: Velitchko G. Tzatchkov, Petronilo E. Cortes-Mejia, J. Manuel Rodriguez-Varela, Jesus Figueroa-Vazquez

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Hydraulic headloss, expressed by the values of friction factor f and Manning’s coefficient n, is an important parameter in designing drainage pipes. Their values normally are taken from manufacturer recommendations, many times without sufficient experimental support. To our knowledge, currently there is no standard procedure for hydraulically testing such pipes. As a result of research carried out at the Mexican Institute of Water Technology, a laboratory testing procedure was proposed and applied on 6 and 12 inches diameter polyvinyl chloride (PVC) and high-density dual wall polyethylene pipe (HDPE) drainage pipes. While the PVC pipe is characterized by naturally smooth interior and exterior walls, the dual wall HDPE pipe has corrugated exterior wall and, although considered smooth, a slightly wavy interior wall. The pipes were tested at full and partially full pipe flow conditions. The tests for full pipe flow were carried out on a 31.47 m long pipe at flow velocities between 0.11 and 4.61 m/s. Water was supplied by gravity from a 10 m-high tank in some of the tests, and from a 3.20 m-high tank in the rest of the tests. Pressure was measured independently with piezometer readings and pressure transducers. The flow rate was measured by an ultrasonic meter. For the partially full pipe flow the pipe was placed inside an existing 49.63 m long zero slope (horizontal) channel. The flow depth was measured by piezometers located along the pipe, for flow rates between 2.84 and 35.65 L/s, measured by a rectangular weir. The observed flow profiles were then compared to computer generated theoretical gradually varied flow profiles for different Manning’s n values. It was found that Manning’s n, that normally is assumed constant for a given pipe material, is in fact dependent on flow velocity and pipe diameter for full pipe flow, and on flow depth for partially full pipe flow. Contrary to the expected higher values of n and f for the HDPE pipe, virtually the same values were obtained for the smooth interior wall PVC pipe and the slightly wavy interior wall HDPE pipe. The explanation of this fact was found in Henry Morris’ theory for smooth turbulent conduit flow over isolated roughness elements. Following Morris, three categories of the flow regimes are possible in a rough conduit: isolated roughness (or semi smooth turbulent) flow, wake interference (or hyper turbulent) flow, and skimming (or quasi-smooth) flow. Isolated roughness flow is characterized by friction drag turbulence over the wall between the roughness elements, independent vortex generation, and dissipation around each roughness element. In this regime, the wake and vortex generation zones at each element develop and dissipate before attaining the next element. The longitudinal spacing of the roughness elements and their height are important influencing agents. Given the slightly wavy form of the HDPE pipe interior wall, the flow for this type of pipe belongs to this category. Based on that theory, an equation for the hydraulic friction factor was obtained. The obtained coefficient values are going to be used in the Mexican design standards.

Keywords: drainage plastic pipes, hydraulic headloss, hydraulic friction factor, Manning’s n

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Authors: Chen-Yu Chen, Wei-Mon Yan, Chi-Nan Lai, Jian-Hao Su

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The proton exchange membrane fuel cell (PEMFC) becomes more important as an alternative energy source recently. Maintaining proper water content in the membrane is one of the key requirements for optimizing the PEMFC performance. The planar membrane humidifier has the advantages of simple structure, low cost, low-pressure drop, light weight, reliable performance and good gas separability. Thus, it is a common external humidifier for PEMFCs. In this work, a planar membrane humidifier for kW-scale PEMFCs is developed successfully. The heat and mass transfer of humidifier is discussed, and its performance is analyzed in term of dew point approach temperature (DPAT), water vapor transfer rate (WVTR) and water recovery ratio (WRR). The DPAT of the humidifier with the counter flow approach reaches about 6°C under inlet dry air of 50°C and 60% RH and inlet humid air of 70°C and 100% RH. The rate of pressure loss of the humidifier is 5.0×10² Pa/min at the torque of 7 N-m, which reaches the standard of commercial planar membrane humidifiers. From the tests, it is found that increasing the air flow rate increases the WVTR. However, the DPAT and the WRR are not improved by increasing the WVTR as the air flow rate is higher than the optimal value. In addition, increasing the inlet temperature or the humidity of dry air decreases the WVTR and the WRR. Nevertheless, the DPAT is improved at elevated inlet temperatures or humidities of dry air. Furthermore, the performance of the humidifier with the counter flow approach is better than that with the parallel flow approach. The DPAT difference between the two flow approaches reaches up to 8 °C.

Keywords: heat and mass transfer, humidifier performance, PEM fuel cell, planar membrane humidifier

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Authors: Yan Pang, Xiang Wang, Zhaomiao Liu

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Droplet microfluidics, in which nanoliter to picoliter droplets acted as individual compartments, are common to a diverse array of applications such as analytical chemistry, tissue engineering, microbiology and drug discovery. The droplet generation in a simplified two dimension T-shape microchannel with the main channel width of 50 μm and the side channel width of 25 μm, is simulated to investigate effects of the forced fluctuation of the side wall on the droplet generation and flow. The periodic fluctuations are applied on a length of the side wall in the main channel of the T-junction with the deformation shape of the double-clamped beam acted by the uniform force, which varies with the flow time and fluctuation periods, forms and positions. The fluctuations under most of the conditions expand the distribution range of the droplet size but have a little effect on the average size, while the shape of the fixed side wall changes the average droplet size chiefly. Droplet sizes show a periodic pattern along the relative time when the fluctuation is forced on the side wall near the T-junction. The droplet emerging frequency is not varied by the fluctuation of the side wall under the same flow rate and geometry conditions. When the fluctuation period is similar with the droplet emerging period, the droplet size shows a nice stability as the no fluctuation case.

Keywords: droplet generation, droplet size, flow flied, forced fluctuation

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Authors: Pakawhat Khumkhreung, Yottana Khunatorn

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The flow pattern inside rectangular intake air duct of 300 MW lignite coal-fired power plant is investigated in order to analyze and reduce overall inlet system pressure drop. The system consists of the 45-degree inlet elbow, the flow instrument, the 90-degree mitered elbow and fans, respectively. The energy loss in each section can be determined by Bernoulli’s equation and ASHRAE standard table. Hence, computational fluid dynamics (CFD) is used in this study based on Navier-Stroke equation and the standard k-epsilon turbulence modeling. Input boundary condition is 175 kg/s mass flow rate inside the 11-m² cross sectional duct. According to the inlet air flow rate, the Reynolds number of airstream is 2.7x10⁶ (based on the hydraulic duct diameter), thus the flow behavior is turbulence. The numerical results are validated with the real operation data. It is found that the numerical result agrees well with the operating data, and dominant loss occurs at the flow rate measurement device. Normally, the air flow rate is measured by the airfoil and it gets high pressure drop inside the duct. To overcome this problem, the airfoil is planned to be replaced with the other type measuring instrument, such as the average pitot tube which generates low pressure drop of airstream. The numerical result in case of average pitot tube shows that the pressure drop inside the inlet airstream duct is decreased significantly. It should be noted that the energy consumption of inlet air system is reduced too.

Keywords: airfoil, average pitot tube, combustion air, CFD, pressure drop, rectangular duct

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Authors: Tatyana Savchuk, Yelena Grinvald, Mohamed Ali, Ramune Sepetiene, Dinara Sadvakassova, Saniya Saussakova, Kuralay Zhangazieva, Dulat Imashpayev

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Introduction. The problem of viral hepatitis B (HBV) takes a vital place in the global health system. The existing risk of HBV transmission through blood transfusions is associated with transfusion of blood taken from infected individuals during the “serological window” period or from patients with latent HBV infection, the marker of which is anti-HBcore. In the absence of information about other markers of hepatitis B, the presence of anti-HBcore suggests that a person may be actively infected or has suffered hepatitis B in the past and has immunity. Aim. To study the risk factors influencing the positive anti-HBcore indicators among the donor population. Materials and Methods. The study was conducted in 2021 in the Scientific and Production Center of Transfusiology of the Ministry of Healthcare in Kazakhstan. The samples taken from blood donors were tested for anti-HBcore, by CLIA on the Architect i2000SR (ABBOTT). A special questionnaire was developed for the blood donors’ socio-demographic characteristics. Statistical analysis was conducted by the R software (version 4.1.1, USA, 2021). Results.5709 people aged 18 to 66 years were included in the study, the proportion of men and women was 68.17% and 31.83%, respectively. The average age of the participants was 35.7 years. A weighted multivariable mixed effects logistic regression analysis showed that age (p<0.001), ethnicity (p<0.05), and marital status (p<0.05) were statistically associated with anti-HBcore positivity. In particular, analysis adjusting for gender, nationality, education, marital status, family history of hepatitis, blood transfusion, injections, and surgical interventions, with a one-year increase in age (adjOR=1.06, 95%CI:1.05-1.07), showed an 6% growth in odds of having anti-HBcore positive results. Those who were russian ethnicity (adjOR=0.65, 95%CI:0.46-0.93) and representatives of other nationality groups (adjOR=0.56, 95%CI:0.37-0.85) had lower odds of having anti-HBcore when compared to Kazakhs when controlling for other covariant variables. Among singles, the odds of having a positive anti-HBcore were lower by 29% (adjOR = 0.71, 95%CI:0.57-0.89) compared to married participants when adjusting for other variables. Conclusions.Kazakhstan is one of the countries with medium endemicity of HBV prevalence (2%-7%). Results of the study demonstrated the possibility to form a profile of risk factors (age, nationality, marital status). Taking into account the data, it is recommended to increase attention to donor questionnaires by adding leading questions and to improve preventive measures to prevent HBV. Funding. This research was supported by a grant from Abbott Laboratories.

Keywords: anti-HBcore, blood donor, donation, hepatitis B virus, occult hepatitis

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Authors: Sonia Ben Hamza, Sabra Habli, Nejla Mahjoub Saïd, Hervé Bournot, Georges Le Palec

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Free surface flows caused by dam breaks in channels or rivers is an attention-getting subject to the engineering practice, however, the studies are few to be reported. In this paper, a numerical investigation of unsteady free surface flows resulting from a dam-breaking in a rectangular channel is studied. Numerical computations were carried out using ANSYS Fluent which is based on the finite volume approach. The air/water interface was modeled with the volume of fluid method (VOF). Verification for a typical dam-break problem is analyzed by comparing the present results with others and very good agreement is obtained. The present approach is then used to predict the characteristics of free surface flow due to the dam breaking in channel. The characteristics of complex unsteady free surface flow in these examples are clearly explained. The numerical results show that the flow became more disturbed after impacting the vertical wall, then a recirculation zone, as well as turbulence phenomena, were created. At this instant, a cavity of air was included on the flow. The results agree well with the experimental data found in the literature.

Keywords: CFD, dam-break, free surface, turbulent flows, VOF

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Authors: Gehan ElAkabawy

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Background: Diabetes mellitus causes severe deteriorations of almost all the organs and systems of the body, as well as significant damage to the oral cavity. The oral changes are mainly related to salivary glands dysfunction characterized by hyposalivation and xerostomia, which significantly reduce diabetic patients’ quality of life. Human dental pulp stem cells represent a promising source for cell-based therapies, owing to their easy, minimally invasive surgical access, and high proliferative capacity. It was reported that the trophic support mediated by dental pulp stem cells can rescue the functional and structural alterations of damaged salivary glands. However, potential differentiation and paracrine effects of human dental pulp stem cells in diabetic-induced parotid gland damage have not been previously investigated. Our study aimed to investigate the therapeutic effects of intravenous transplantation of human dental pulp stem cells (hDPSCs) on parotid gland injury in a rat model of streptozotocin (STZ)-induced type 1 diabetes. Methods: Thirty Sprague-Dawley male rats were randomly categorised into three groups: control, diabetic (STZ), and transplanted (STZ+hDPSCs). hDPSCs or vehicle was injected into the tail vein 7 days after STZ injection. The fasting blood glucose levels were monitored weekly. A glucose tolerance test was performed, and the parotid gland weight, salivary flow rate, oxidative stress indices, parotid gland histology, and caspase-3, vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA) expression in parotid tissues were assessed 28 days post-transplantation. Results: Transplantation of hDPSCs downregulated blood glucose, improved the salivary flow rate, and reduced oxidative stress. The cells migrated to, survived, and differentiated into acinar, ductal, and myoepithelial cells in the STZ-injured parotid gland. Moreover, they downregulated the expression of caspase-3 and upregulated the expression of VEGF and PCNA, likely exerting pro-angiogenetic and antiapoptotic effects and promoting endogenous regeneration. In addition, the transplanted cells enhanced the parotid nitric oxide (NO) -tetrahydrobiopterin (BH4) pathway. Conclusions: Our results show that hDPSCs can migrate to and survive within the STZ-injured parotid gland, where they prevent its functional and morphological damage by restoring normal glucose levels, differentiating into parotid cell populations, and stimulating paracrine-mediated regeneration. Thus, hDPSCs may have therapeutic potential in the treatment of diabetes-induced parotid gland injury.

Keywords: dental pulp stem cells, diabetes, streptozotocin, parotid gland

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Authors: C. F. Alegretti, F. R. Cunha, R. G. Gontijo

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This work investigates the effects of an applied magnetic field on the geometry-driven boundary layer detachment flow of a ferrofluid over a sudden expansion. Both constitutive equation and global magnetization equation for a ferrofluid are considered. Therefore, the proposed formulation consists in a coupled magnetic-hydrodynamic problem. Computational simulations are carried out in order to explore, not only the viability to control flow instabilities, but also to evaluate the consistency of theoretical aspects. The unidirectional sudden expansion in a ferrofluid flow is investigated numerically under the perspective of Ferrohydrodynamics in a two-dimensional domain using a Finite Differences Method. The boundary layer detachment induced by the sudden expansion results in a recirculating zone, which has been extensively studied in non-magnetic hydrodynamic problems for a wide range of Reynolds numbers. Similar investigations can be found in literature regarding the sudden expansion under the magnetohydrodynamics framework, but none considering a colloidal suspension of magnetic particles out of the superparamagnetic regime. The vorticity-stream function formulation is implemented and results in a clear coupling between the flow vorticity and its magnetization field. Our simulations indicate a systematic decay on the length of the recirculation zone as increasing physical parameters of the flow, such as the intensity of the applied field and the volume fraction of particles. The results all are discussed from a physical point of view in terms of the dynamical non-dimensional parameters. We argue that the decrease/reduction in the recirculation region of the flow is a direct consequence of the magnetic torque balancing the action of the torque produced by viscous and inertial forces of the flow. For the limit of small Reynolds and magnetic Reynolds parameters, the diffusion of vorticity balances the diffusion of the magnetic torque on the flow. These mechanics control the growth of the recirculation region.

Keywords: boundary layer detachment, ferrofluid, ferrohydrodynamics, magnetization, sudden expansion

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Authors: Ahmad K. Samaila, Basant K. Jha

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This paper presents the effects of suction/injection of transient/steady natural convection flow of reactive viscous fluid in a vertical porous pipe. The mathematical model capturing the time dependent flow of viscous reactive fluid is solved using implicit finite difference method while the corresponding steady state model is solved using regular perturbation technique. Results of analytical and numerical solutions are reported for various parametric conditions to illustrate special features of the solutions. The coefficient of skin friction and rate of heat transfer are obtained and illustrated graphically. The numerical solution is shown to be in excellent agreement with the closed form analytical solution. It is interesting to note that time required to reach steady state is higher in case of injection in comparison to suction.

Keywords: porous pipe, reactive viscous fluid, transient natural-convective flow, analytical solution

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Authors: Shashikant Iyengar, Jasmeet Kaur, Anup Singh, Arun Kumar, Ira Sahay

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Insulin resistance (IR) is a condition that occurs when cells in the body become less responsive to insulin, leading to higher levels of both insulin and glucose in the blood. This condition is linked to metabolic syndromes, including diabetes. It is crucial to address IR promptly after diagnosis to prevent long-term complications associated with high insulin and high blood glucose. This four-month case study highlights the importance of treating the underlying condition to manage diabetes effectively. Insulin is essential for regulating blood sugar levels by facilitating the uptake of glucose into cells for energy or storage. In IR individuals, cells are less efficient at taking up glucose from the blood resulting in elevated blood glucose levels. As a result of IR, beta cells produce more insulin to make up for the body's inability to use insulin effectively. This leads to high insulin levels, a condition known as hyperinsulinemia, which further impairs glucose metabolism and can contribute to various chronic diseases. In addition to regulating blood glucose, insulin has anti-catabolic effects, preventing the breakdown of molecules in the body, such as inhibiting glycogen breakdown in the liver, inhibiting gluconeogenesis, and inhibiting lipolysis. If a person is insulin-sensitive or metabolically healthy, an optimal level of insulin prevents fat cells from releasing fat and promotes the storage of glucose and fat in the body. Thus optimal insulin levels are crucial for maintaining energy balance and plays a key role in metabolic processes. During the four-month study, researchers looked at the impact of a low-carb dietary (LCD) intervention on two male individuals (A & B) who had Type-2 diabetes. Althoughvneither of these individuals were obese, they were both slightly overweight and had abdominal fat deposits. Before the trial began, important markers such as fasting blood glucose (FBG), triglycerides (TG), high-density lipoprotein (HDL) cholesterol, and Hba1c were measured. These markers are essential in defining metabolic health, their individual values and variability are integral in deciphering metabolic health. The ratio of TG to HDL is used as a surrogate marker for IR. This ratio has a high correlation with the prevalence of metabolic syndrome and with IR itself. It is a convenient measure because it can be calculated from a standard lipid profile and does not require more complex tests. In this four-month trial, an improvement in insulin sensitivity was observed through the ratio of TG/HDL, which, in turn, improves fasting blood glucose levels and HbA1c. For subject A, HbA1c dropped from 13 to 6.28, and for subject B, it dropped from 9.4 to 5.7. During the trial, neither of the subjects were taking any diabetic medications. The significant improvements in their health markers, such as better glucose control, along with an increase in energy levels, demonstrate that incorporating LCD interventions can effectively manage diabetes.

Keywords: metabolic disorder, insulin resistance, type-2 diabetes, low-carb nutrition

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Authors: R. P. Hewawasam, M. H. A. D. de Silva, M. A. G. Iresha

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Obesity is associated with an increased risk of developing insulin resistance. Insulin resistance often progresses to type-2 diabetes mellitus and is linked to a wide variety of other pathophysiological features including hypertension, hyperlipidemia, atherosclerosis (metabolic syndrome) and polycystic ovarian syndrome. Macrosomia is common in infants born to not only women with gestational diabetes mellitus but also non-diabetic obese women. During the past two decades, obesity in children and adolescents has risen significantly in Asian populations including Sri Lanka. There is increasing evidence to believe that infants who are born large for gestational age (LGA) are more likely to be obese in childhood. It is also established from previous studies that Asian populations have higher percentage body fat at a lower body mass index compared to Caucasians. High leptin levels in cord blood have been reported to correlate with fetal adiposity at birth. Previous studies have also shown that cord blood C-peptide and insulin levels are significantly and positively correlated with birth weight. Therefore, the objective of this preliminary study was to determine the relationship between parameters of fetal insulin resistance such as leptin, C-peptide and insulin and the birth weight of the newborn in a study population in Southern Sri Lanka. Umbilical cord blood was collected from 90 newborns and the concentration of insulin, leptin, and C-peptide were measured by ELISA technique. Birth weight, length, occipital frontal, chest, hip and calf circumferences of newborns were measured and characteristics of the mother such as age, height, weight before pregnancy and weight gain were collected. The relationship between insulin, leptin, C-peptide, and anthropometrics were assessed by Pearson’s correlation while the Mann-Whitney U test was used to assess the differences in cord blood leptin, C-peptide, and insulin levels between groups. A significant difference (p < 0.001) was observed between the insulin levels of infants born LGA (18.73 ± 0.64 µlU/ml) and AGA (13.08 ± 0.43 µlU/ml). Consistently, A significant increase in concentration (p < 0.001) was observed in C-peptide levels of infants born LGA (9.32 ± 0.77 ng/ml) compared to AGA (5.44 ± 0.19 ng/ml). Cord blood leptin concentration of LGA infants (12.67 ng/mL ± 1.62) was significantly higher (p < 0.001) compared to the AGA infants (7.10 ng/mL ± 0.97). Significant positive correlations (p < 0.05) were observed among cord leptin levels and the birth weight, pre-pregnancy maternal weight and BMI between the infants of AGA and LGA. Consistently, a significant positive correlation (p < 0.05) was observed between the birth weight and the C peptide concentration. Significantly high concentrations of leptin, C-peptide and insulin levels in the cord blood of LGA infants suggest that they may be involved in regulating fetal growth. Although previous studies suggest comparatively high levels of body fat in the Asian population, values obtained in this study are not significantly different from values previously reported from Caucasian populations. According to this preliminary study, maternal pre-pregnancy BMI and weight may contribute as significant indicators of cord blood parameters of insulin resistance and possibly the birth weight of the newborn.

Keywords: large for gestational age, leptin, C-peptide, insulin

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Authors: A. L. Qureshi, A. A. Mahessar, A. Baloch

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Flood wave propagation in river channel flow can be enunciated by nonlinear equations of motion for unsteady flow. However, it is difficult to find analytical solution of these complex non-linear equations. Hence, verification of the numerical model should be carried out against field data and numerical predictions. This paper presents the verification of developed finite element model applying for unsteady flow in the open channels. The results of a proposed model indicate a good matching with both Preissmann scheme and HEC-RAS model for a river reach of 29 km at both sites (15 km from upstream and at downstream end) for discharge hydrographs. It also has an agreeable comparison with the Preissemann scheme for the flow depth (stage) hydrographs. The proposed model has also been applying to forecast daily discharges at 400 km downstream from Sukkur barrage, which demonstrates accurate model predictions with observed daily discharges. Hence, this model may be utilized for predicting and issuing flood warnings about flood hazardous in advance.

Keywords: finite element method, Preissmann scheme, HEC-RAS, flood forecasting, Indus river

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Authors: Khalil Khanafer

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This study emphasizes on analyzing the effect of flow conditions and the geometric variation of the microcantilever’s bluff body on the microcantilever detection capabilities within a fluidic device using a finite element fluid-structure interaction model. Such parameters include inlet velocity, flow direction, and height of the microcantilever’s supporting system within the fluidic cell. The transport equations are solved using a finite element formulation based on the Galerkin method of weighted residuals. For a flexible microcantilever, a fully coupled fluid-structure interaction (FSI) analysis is utilized and the fluid domain is described by an Arbitrary-Lagrangian–Eulerian (ALE) formulation that is fully coupled to the structure domain. The results of this study showed a profound effect on the magnitude and direction of the inlet velocity and the height of the bluff body on the deflection of the microcantilever. The vibration characteristics were also investigated in this study. This work paves the road for researchers to design efficient microcantilevers that display least errors in the measurements.

Keywords: fluidic cell, FSI, microcantilever, flow direction

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Authors: Ashmita Mukherjee, Yogesh Harishchandra Kabutare, Suritra Bandyopadhyay, Paulomi Ghosh

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Uncontrolled bleeding in the battlefield and the operation rooms can lead to serious injuries, trauma and even be lethal. Keratin was reported to be a haemostatic material which rapidly activates thrombin followed by activation of fibrinogen leading to the formation of insoluble fibrin. Also platelets, the main initiator of haemostasis are reported to adhere to keratin. However, the major limitation of pure keratin as a biomaterial is its poor physical property and corresponding low mechanical strength. To overcome this problem, keratin was cross-linked with alginate to increase its mechanical stability. In our study, Keratin extracted from feather waste showed yield of 80.5% and protein content of 8.05 ± 0.43 mg/mL (n=3). FTIR and CD spectroscopy confirmed the presence of the essential functional groups and preservation of the secondary structures of keratin. The keratin was then cross-linked with alginate to make a dope. The dope was used to draw fibers of desired diameters in a suitable coagulation bath using a customized wet spinning setup. The resultant morphology of keratin fibers was observed under a brightfield microscope. The FT-IR analysis implied that there was a presence of both keratin and alginate peaks in the fibers. The cross-linking was confirmed in the keratin alginate fibers by a shift of the amide A and amide B peaks towards the right and disappearance of the peak for N-H stretching (1534.68 cm-1). Blood was drawn in citrate vacutainers for whole blood clotting test and blood clotting kinetics, which showed that the keratin fibers could accelerate blood coagulation compared to that of alginate fibers and tissue culture plate. Additionally, cross-linked keratin-alginate fiber was found to have lower haemolytic potential compared to alginate fiber. Thus, keratin cross-linked fibers can have potential applications to combat unrestrained bleeding.

Keywords: biomaterial, biowaste, fiber, keratin

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Authors: Mustafa M. Donma, Orkide Donma

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Obesity is defined as a severe chronic disease characterized by a low-grade inflammatory state. Therefore, inflammatory markers gained utmost importance during the evaluation of obesity and metabolic syndrome (MetS), a disease characterized by central obesity, elevated blood pressure, increased fasting blood glucose and elevated triglycerides or reduced high density lipoprotein cholesterol (HDL-C) values. Some inflammatory markers based upon complete blood cell count (CBC) are available. In this study, it was questioned which inflammatory marker was the best to evaluate the differences between various obesity groups. 514 pediatric individuals were recruited. 132 children with MetS, 155 morbid obese (MO), 90 obese (OB), 38 overweight (OW) and 99 children with normal BMI (N-BMI) were included into the scope of this study. Obesity groups were constituted using age- and sex-dependent body mass index (BMI) percentiles tabulated by World Health Organization. MetS components were determined to be able to specify children with MetS. CBC were determined using automated hematology analyzer. HDL-C analysis was performed. Using CBC parameters and HDL-C values, ratio markers of inflammation, which cover neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), monocyte-to-HDL-C ratio (MHR) were calculated. Statistical analyses were performed. The statistical significance degree was considered as p < 0.05. There was no statistically significant difference among the groups in terms of platelet count, neutrophil count, lymphocyte count, monocyte count, and NLR. PLR differed significantly between OW and N-BMI as well as MetS. Monocyte-to HDL-C value exhibited statistical significance between MetS and N-BMI, OB, and MO groups. HDL-C value differed between MetS and N-BMI, OW, OB, MO groups. MHR was the ratio, which exhibits the best performance among the other CBC-based inflammatory markers. On the other hand, when MHR was compared to HDL-C only, it was suggested that HDL-C has given much more valuable information. Therefore, this parameter still keeps its value from the diagnostic point of view. Our results suggest that MHR can be an inflammatory marker during the evaluation of pediatric MetS, but the predictive value of this parameter was not superior to HDL-C during the evaluation of obesity.

Keywords: children, complete blood cell count, high density lipoprotein cholesterol, metabolic syndrome, obesity

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Authors: Jafar Mortadha, Imran Qureshi

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This research explains and compares the modern techniques used for measuring the flow angles of a flowing fluid with the traditional technique of using multi-hole pressure probes. In particular, the focus of the study is on four-hole probes, which offer great reliability and benefits in several applications where the use of modern measurement techniques is either inconvenient or impractical. Due to modern advancements in manufacturing, small multi-hole pressure probes can be made with high precision, which eliminates the need for calibrating every manufactured probe. This study aims to improve the range of calibration maps for a four-hole probe to allow high flow angles to be measured accurately. The research methodology comprises a literature review of the successful calibration definitions that have been implemented on five-hole probes. These definitions are then adapted and applied on a four-hole probe using a set of raw pressures data. A comparison of the different definitions will be carried out in Matlab and the results will be analyzed to determine the best calibration definition. Taking simplicity of implementation into account as well as the reliability of flow angles estimation, an adapted technique from a research paper written in 2002 offered the most promising outcome. Consequently, the method is seen as a good enhancement for four-hole probes and it can substitute for the existing calibration definitions that offer less accuracy.

Keywords: calibration definitions, calibration maps, flow measurement techniques, four-hole probes, multi-hole pressure probes

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Authors: Sumera, Sanila Amber, Fatima Javed Mirza, Amjad Ali, Saadia Zahid

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Glioblastoma multiforme (GBM) is a widely spread and fatal primary brain tumor with an increased risk of relapse in spite of aggressive treatment. The current procedures for GBM diagnosis include invasive procedures i.e. resection or biopsy, to acquire tumor mass. Implementation of negligibly invasive tests as a potential diagnostic technique and biofluid-based monitoring of GBM stresses on discovering biomarkers in CSF and blood. Therefore, we performed a comprehensive in silico analysis to identify potential circulating biomarkers for GBM. Initially, six gene and protein databases were utilized to mine brain-specific proteins. The resulting proteins were filtered using a channel of five tools to predict the secretory proteins. Subsequently, the expression profile of the secreted proteins was verified in the brain and blood using two databases. Additional verification of the resulting proteins was done using Plasma Proteome Database (PPD) to confirm their presence in blood. The final set of proteins was searched in literature for their relationship with GBM, keeping a special emphasis on secretome proteome. 2145 proteins were firstly mined as brain-specific, out of which 69 proteins were identified as secretory in nature. Verification of expression profile in brain and blood eliminated 58 proteins from the 69 proteins, providing a final list of 11 proteins. Further verification of these 11 proteins further eliminated 2 proteins, giving a final set of nine secretory proteins i.e. OPCML, NPTX1, LGI1, CNTN2, LY6H, SLIT1, CREG2, GDF1 and SERPINI1. Out of these 9 proteins, 7 were found to be linked to GBM, whereas 2 proteins are not investigated in GBM so far. We propose that these secretory proteins can serve as potential circulating biomarker signatures of GBM and will facilitate the development of minimally invasive diagnostic methods and novel therapeutic interventions for GBM.

Keywords: glioblastoma multiforme, secretory proteins, brain secretome, biomarkers

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Authors: Adesola O. Orimoloye, Mohammed N. Kajama, Edward Gobina

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Gas permeation of Oxygen [O2] and Nitrogen [N2] were investigated at room temperature using 15 and 6000nm pore diameter tubular commercial alumina ceramic membranes with pressure values ranging 1.00 to 2.50 bar. The flow rates of up to 2.59 and 2.77 l/min were achieved for O2 and N2 respectively. The ratio of O2/N2 flow rates were used to compute the O2/N2 selectivity. The experimental O2/N2 selectivity obtained for 15 nm was 1.05 while the 6000 nm indicated 0.95.

Keywords: gas separation, nitrogen, oxygen, selectivity

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Authors: Vahab Behmanesh

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Metabolic syndrome is defined as having at least three of the five metabolic risk factors, including abdominal obesity, high blood pressure, high triglycerides, low HDL, and insulin resistance. Lifestyle changes towards reducing physical activity, unhealthy eating habits Especially the high-fat and high-carbohydrate diet is directly related to metabolic syndrome, and due to the epidemic of overweight and sedentary life, metabolic syndrome is a serious problem worldwide. On the other hand, vitamin D deficiency is considered as one of the most common problems in the world, which is related to the dysfunction of beta cells and insulin resistance, and therefore, vitamin D deficiency is considered as a factor in the occurrence of metabolic syndrome. 40 subjects (age: 16.12 ± 4.4 years and body mass index 25.61 ± 4.4 kg/m2) were randomly assigned to groups of aerobic exercise and placebo, aerobic exercise and vitamin D and placebo (no exercise) were divided. Vitamin D was taken at a dose of 50,000 units per week in a double-blind format for eight weeks, and the daily aerobic exercise program was performed for 50 to 60 minutes, three doses per week, with an intensity of 50-60% of the maximum heart rate. From one-way analysis of variance, Factorial variance analysis (2x2) repeated measurement and correlated t-test were used for data analysis. Aerobic exercise and vitamin D intake reduced all metabolic risk indicators and blood insulin (P < 0.05). However, the subjective feeling of hunger did not change significantly (P < 0.05). Regarding waist circumference and blood glucose, the effect of exercise combined with vitamin D consumption was greater than the corresponding effect in the vitamin D group (P < 0.05). Aerobic exercises and vitamin D intake are safe and effective for improving cardiometabolic health, Imam adds vitamin D to the exercise program has more benefits for weight and blood sugar control, which suggests prescribing it for patients with metabolic syndrome.

Keywords: vitamin D, aerobic exercise, metabolic control, adolescents

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Authors: R. S. Dinesh Madhavan, M. Logaraj

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Background: Recent studies have documented an increase in the risk of cardiovascular diseases (CVD) and a high rate of progression to hypertension in persons with pre hypertension. The risk factors for the growing burden of cardiovascular diseases especially hypertension, diabetes, overweight or obesity and waist hip ratio are increasing. Much study has not been done on cardiovascular risk factors associated with blood pressure (BP) among college students in Indian population. Objectives: The objective of our study was to estimate the prevalence of prehypertension among male students and to assess the association between prehypertension and risk factors for cardiovascular diseases. Material and Methods: A cross-sectional study was conducted among students of a university situated in the suburban area of Chennai. A total of 403 students was studied which included 200 medical and 203 engineering students. The information on selected socio-demographic variables were collected with the help of pre tested structured questionnaire. Measurements of height, weight, blood pressure and postprandial blood glucose were carried out as per standard procedure. Results: The mean age of the participants was 19.56 ± 1.67years. The mean systolic and diastolic blood pressure were 125.80±10.03 mm of Hg and 78.96 ±11.75mm of Hg. The average intake of fruits and vegetable per week were 4.34 ±3.47days and 6.55±4.39 days respectively. Use of smoke and smokeless tobacco were 27.3% and 3% respectively. About 30.3% of the students consume alcohol. Nearly 45.9 % of them did not practice regular exercise. About 29 % were overweight and 5.7% were obese, 24.8% were with waist circumference above 90 centimeters. The prevalence of pre hypertension and hypertension was 49.6% and 19.1% among male students. The prevalence of pre hypertension was higher in medical students (51.5%) compared to engineering students (47.8%). Higher risk of being pre hypertensive were noted above the age of 20 years (OR=4.32), fruit intake less than 3 days a week (OR= 1.03), smokers (OR= 1.13), alcohol intake (OR=1.56), lack of physical exercise (OR=1.90), BMI of more than 25 kg/m2 (OR=1.99). But statistically significant difference was noted between pre hypertensive and normotensive for age (p<0.0001), lack of physical exercise (p=0.004) and BMI (p=0.015). Conclusion: In conclusion nearly half of the students were pre hypertensive. Higher prevalence of smoking, alcohol intake, lack of physical exercise, overweight and increased waist circumference and postprandial blood sugar more than 140 mg/dl was noted among pre-hypertensive compared to normotensive.

Keywords: cardiovascular diseases, prehypertension, risk factors, undergraduate Students

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Authors: Kassahun Birhanu Tadesse, Megersa Olumana Dinka

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Reliable future river flow information is basic for planning and management of any river systems. For data scarce river system having only a river flow records like the Waterval River, a univariate time series models are appropriate for river flow forecasting. In this study, a univariate Seasonal Autoregressive Integrated Moving Average (SARIMA) model was applied for forecasting Waterval River flow using GRETL statistical software. Mean monthly river flows from 1960 to 2016 were used for modeling. Different unit root tests and Mann-Kendall trend analysis were performed to test the stationarity of the observed flow time series. The time series was differenced to remove the seasonality. Using the correlogram of seasonally differenced time series, different SARIMA models were identified, their parameters were estimated, and diagnostic check-up of model forecasts was performed using white noise and heteroscedasticity tests. Finally, based on minimum Akaike Information (AIc) and Hannan-Quinn (HQc) criteria, SARIMA (3, 0, 2) x (3, 1, 3)12 was selected as the best model for Waterval River flow forecasting. Therefore, this model can be used to generate future river information for water resources development and management in Waterval River system. SARIMA model can also be used for forecasting other similar univariate time series with seasonality characteristics.

Keywords: heteroscedasticity, stationarity test, trend analysis, validation, white noise

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Authors: M. Abbasi

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A spillway structure is used to pass excess water and floods from upstream or upstream to downstream or tributary. The spillway is considered one of the most key members of the dam, and the failure of many dams is attributed to the inefficiency of their spillway. Weirs should be selected as strong, reliable and high-performance structures, and weirs should be ready for use in all conditions and able to drain the flood so that we do not witness many casualties and financial losses when a flood occurs. The purpose of this study is to simulate the flow pattern passing over the peak spillway in order to optimize and adjust the height of the spillway walls. In this research, the effect of the shape of the side wings on the flow pattern over the peak spillways of the Gotvand reservoir dam was simulated and modelled using Flow3D software. In this research, side wings with rounded walls with six different approach angles were used. In addition, the different value of H/Hd was used to check the effect of the tank head. The results showed that with the constant H/Hd ratio and the increase of the approach angle of the side wing, the flow depth first decreases and then increases. These changes were the opposite regarding the depth average speed of the flow and the depth average concentration of the air entering the flow. At the same time, with the constant angle of approach of the side wing and with the increase of H/Hd ratio, the flow depth increases. In general, a correct understanding of the operation of overflows and a correct design can significantly reduce construction costs and solve flooding problems.

Keywords: effect of the shape, gotvand reservoir dam, narrowing coefficients, supports of the gates

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Authors: Ashkan Javadzadegan, Aitak Javadzadegan, Babak Fakhim

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One of possible ways to retard movement of fluid is through applying an external magnetic field. In this regard, this study is focused on the effect of a uniform transverse magnetic field on fluid flow behavior inside a channel with a local symmetric constriction. Also, Ellis Non-Newtonian model is implemented to address the effects of shear-dependent viscosity. According to the results, the flow separation downstream of the constriction can be controlled by applying an external magnetic field and/or manipulating the shear-thinning degree of fluid. It is also demonstrated that pressure drop increases by an increase in the strength of the magnetic field.

Keywords: magnetic field, non-Newtonian, separation, shear thinning

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Authors: Kennedy Zinn, Chris Anderson

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Chronic Covid syndrome (CCS) is a condition in which individuals who test positive for Covid-19 experience persistent symptoms after recovering from the virus. CCS affects every organ system, including the central nervous system. Neurological “long-haul” symptoms last from a few weeks to several months and include brain fog, chronic fatigue, dyspnea, mood dysregulation, and headaches. Data suggest that 10-30% of individuals testing positive for Covid-19 develop CCS. Current literature indicates a decreased quality of life in persistent symptoms. CCS is a pervasive and pernicious COVID-19 sequelae. More research is needed to understand risk factors, impact, and possible interventions. Research frequently cites cytokine storming as noteworthy etiology in CCS. Cytokine storming is a malfunctional immune response and facilitates multidimensional interconnected physiological responses. The most prominent responses include abnormal blood flow, hypoxia/hypoxemia, inflammation, and endothelial damage. Neurological impairments and pathogenesis in CCS parallel that of traumatic brain injury (TBI). Both exhibit impairments in memory, cognition, mood, sustained attention, and chronic fatigue. Evidence suggests abnormal blood flow, inflammation, and hypoxemia as shared causal factors. Cytokine storming is also typical in mTBI. The shared characteristics in symptoms and etiology suggest potential parallel routes of investigation that allow for better understanding of CCS. Research on the effect of altitude in mTBI varies. Literature finds decreased rates of concussions at higher altitudes. Other studies suggest that at a higher altitude, pre-existing mTBI symptoms are exacerbated. This may mean that in CCS, the geographical location where individuals live and the location where individuals experienced acute Covid-19 symptoms may influence the severity and risk of developing CCS. It also suggests that clinics which treat mTBI patients could also provide benefits for those with CCS. This study aims to examine the relationships between altitude and CCS as a risk factor and investigate the longevity and severity of symptoms in different altitudes. Existing patient data from a concussion clinic using fMRI scans and self-reported symptoms will be used for approximately 30 individuals with CCS symptoms. The association between acclimated altitude and CCS severity will be analyzed. Patients will be classified into low, medium, and high altitude groups and compared for differences on fMRI severity scores and self-reported measures. It is anticipated that individuals living in lower altitudes are at higher risk of developing more severe neuropsychological symptoms in CCS. It is also anticipated that a treatment approach for mTBI will also be beneficial to those with CCS.

Keywords: altitude, chronic covid syndrome, concussion, covid brain, EPIC treatment, fMRI, traumatic brain injury

Procedia PDF Downloads 129

Authors: He Li Wen, Meng Qing Xiang, Li De Yong, Zhang Ya Wei, Ren Li Ping

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Stress always exerts some extent adverse effects on the animal production, food safety and quality concerns. Stress is commonly-seen in livestock industry, but there is rare literature focusing on the effects of nutrition stress. What’s more, the research always concentrates on the effect of single stress additionally, there is scarce information about the stress effect on waterfowl like goose as they are commonly thought to be tolerant to stress. To our knowledge, it is not always true. The object of this study was to evaluate the response of growing Greylag geese offered different fiber sources to the comprehensive stress, primarily involving the procedures of fasting, transport, capture, etc. The birds were randomly selected to rear with the diets differing in fiber source, being corn straw silage (CSS), steam-exploded corn straw (SECS), steam-exploded wheat straw (SEWS), and steam-exploded rice straw (SERS), respectively. Blood samples designated for the determination of stress status were collected before (pre-stress ) and after (post-stress ) the stressors carried out. No difference (P>0.05) was found on the pre-stress blood parameters of growing Greylags fed alternative fiber sources. Irrespective of the dietary differences, the comprehensive stress decreased (P<0.01) the concentration of SOD and increased (P<0.01) that of CK. Between the dietary treatments, the birds fed CSS had a higher (P<0.05)post-stress concentration of MDA than those offered SECS, along with a similarity to those fed the other two fiber sources. There was no difference (P>0.05) found on the stress response of the birds fed different fiber sources. In conclusion, SOD and CK concentration in blood may be more sensitive in indicating stress status and dietary fiber source exerted no effect on the stress response of growing Greylags. There is little chance to improve the stress status by ingesting different fiber sources.

Keywords: blood parameter, fiber source, Greylag goose, stress

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Authors: Xiangji Guo, Bo Zhang

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In this paper, the phenomenon of vortex breakdown in a vortex tube was analyzed within the scope of unsteady character in swirl flows. A 3-D Unsteady Reynolds-averaged Navier–Stokes (URANS) closed by the Reynolds Stress Model (RSM) was adopted to simulate the large-scale vortex structure in vortex tube, and the numerical model was verified by the steady results. The swirl number was calculated for the vortex tube and the flow field was classed as strong swirl flow. According to the results, a time-dependent spiral flow field gyrates around a central recirculation zone which is precessing around the axis of the tube, and manifests the flow structure is the spiral type (S-type) vortex breakdown. The vortex breakdown is crucial for the formation of the central recirculation zone (CRZ), a further discussion was about the affection on CRZ with the different external conditions of vortex tube, the study on the unsteady characters was expected to hope to design of vortex tube and analyze the energy separation effect.

Keywords: vortex tube, vortex breakdown, central recirculation zone, unsteady, energy separation

Procedia PDF Downloads 309