Search results for: magnetoelastically induced perpendicular magnetic anisotropy

Authors: Rabah Bensaha, Badreddine Toubal

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We investigate the structural, optical and magnetic properties of TiO2, Co-doped TiO2, Ni-doped TiO2 and Co-Ni co-doped TiO2 thin films prepared by the sol-gel dip coating method. Fully anatase phase was obtained by adding metal ions without any detectable impurity phase or oxide formed. AFM and SEM micrographs clearly confirm that the addition of Co-Ni affects the shape of anatase nanoparticles. The crystallite sizes and surface roughness of TiO2 films increase with Co-doping, Ni-doping and Co–Ni co-doping, respectively. The refractive index, thickness and optical band gap values of the films were obtained by means of optical transmittance spectra measurements. The band gap of TiO2 sample was decreased by Co-doping, Ni-doping and Co–Ni co-doping TiO2 films. Both undoped and Co-Ni co-doped films were found to be ferromagnetic at room temperature may due to the presence of oxygen vacancy defect and the probable formation of metal clusters Co-Ni.

Keywords: Co-Ni co-doped, anatase TiO2, ferromagnetic, sol-gel method, thin films

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Authors: Livhuwani Muthelo, R. N. Malema, T. M. Mothiba

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Long term exposure to excessive noise in the mining industry increases the risk of noise induced hearing loss, with consequences for employee’s health, productivity and the overall quality of life. Objective: The objective of this study was to investigate the factors that contribute to Noise Induced Hearing Loss amongst employees at the Platinum mine in the Limpopo Province, South Africa. Study method: A qualitative, phenomenological, exploratory, descriptive, contextual design was applied in order to explore and describe the contributory factors. Purposive non-probability sampling was used to select 10 male employees who were diagnosed with NIHL in the year 2014 in four mine shafts, and 10 managers who were involved in a Hearing Conservation Programme. The data were collected using semi-structured one-on-one interviews. A qualitative data analysis of Tesch’s approach was followed. Results: The following themes emerged: Experiences and challenges faced by employees in the work environment, hearing protective device factors and management and leadership factors. Hearing loss was caused by partial application of guidelines, policies, and procedures from the Department of Minerals and Energy. Conclusion: The study results indicate that although there are guidelines, policies, and procedures available, failure in the implementation of one element will affect the development and maintenance of employees hearing mechanism. It is recommended that the mine management should apply the guidelines, policies, and procedures and promptly repair the broken hearing protective devices.

Keywords: employees, factors, noise induced hearing loss, noise exposure

Procedia PDF Downloads 127

Authors: Swati Kundu, Seemi Farhat Basir, Luqman A. Khan

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Acute and chronic exposure to arsenic and mercury is known to produce vasoconstriction. Pathways involved in this hypercontraction and their relative contribution are not understood. In this study, we measure agonist-induced contraction of isolated rat aorta exposed to arsenic and mercury aorta and delineate pathways mediating this effect. PE-induced hypercontraction of 37% and 32% was obtained with 25 µM As(III) and 6 nM Hg(II), respectively. Isometric contraction measurements in the presence of apocynin, verapamil and sodium nitroprusside indicates that the major cause of increased contraction is reactive oxygen species and depletion of nitric oxide. Calcium influx plays a minor role in both arsenic and mercury caused hypercontraction. In the unexposed aorta, eugenol causes relaxation by inhibiting ROS and elevating NO, linalool by blocking voltage dependent calcium channel (VDCC) and elevating NO, and carvone by blocking calcium influx through VDDC. Since arsenic and mercury caused hypercontraction is mediated by increased ROS and depletion of nitric oxide, we hypothesize that molecules which neutralize ROS or elevate NO will be better ameliorators. In line with this argument, we find eugenol to be the best ameliorator of arsenic and mercury hypercontraction followed by linalool and carvone.

Keywords: carvone, eugenol, linalool, mercury

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Authors: Kun Chun, Jin-Chun Heo, Sang-Han Lee

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Asthma is a chronic airway inflammatory disease characterized by the infiltration of inflammatory cells and tissue remodeling. In this study, we examined the anti-asthmatic activity of a derivative of L-allo threonine by in vitro and in vivo anti-asthmatic assays. Ovalbumin (OVA)-induced C57BL/6 mice were used to analyze lung inflammation and cytokine expressions for exhibiting anti-atopic activity of the derivative. LX519290, a derivative of L-allo threonine, induced an increased IFN-γ and a decreased IL-10 mRNA level. This compound exhibited potent anti-asthmatic activity by decreasing immune cell infiltration in the lung, and IL-4 and IL-13 cytokine levels in the serum of OVA-induced mice. These results indicated that chronic airway injury was decreased by LX519290. We also assessed that LX519290 inhibits infiltration of immune cell, mucus release and cytokine expression in an in vivo model. Our results collectively suggest that the L-allo threonine is effective in alleviating asthmatic symptoms by treating inflammatory factors in the lung.

Keywords: asthma, L -allo threonine, LX519290, mice

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Authors: Boonyalitpun P., Pruckpattranon P., Thonghom A., Rotpenpian N.

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Osteoarthritis is a musculoskeletal and neuromuscular abnormality, masticatory muscle, and other tissue that causes pain and breaks down the articular surface of the temporomandibular joint (TMJ). The aim of this study is to investigate the change in the mandibular condyle, in terms of thickness and porosity, and osteoclast marker in the mandibular condyle of TMJ induced osteoarthritis mice (TMJ-OA mice). We investigated the bony changes in the TMJ structure of a complete Freund adjuvant (CFA)-injected TMJ in a mice model over 28 days. On day 28, we observed any change in the TMJ by a micro computed tomography scan (micro-CT scan) in the parameters of trabecular microarchitecture. Then we studied the thickness of the condyles by hematoxylin and eosin staining. Moreover, we calculated the area around the TMJ’s condylar head containing the osteoclast expression by TRAP (Tartrate-resistant acid phosphatase) immunohistochemistry staining. The result found that the parameter of a micro-CT scan was no different from microarchitecture in the TMJ compared with the control group; however, mandibular condyles of the TMJ-OA group was significantly thinner than the control groups, and the osteoclast expression significantly increased in the TMJ-OA group. Therefore, our findings suggest that CFA-induced TMJ-OA represents an expression of osteoclast mandibular condyle of the TMJ, which is the proposed mechanism for a TMJ-OA model.

Keywords: condyle, osteoarthritis, osteoclast, temporomandibular joint

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Authors: Ying Shen, Weihua Zhu

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Medical images are important to help identifying different diseases, for example, Magnetic resonance imaging (MRI) can be used to investigate the brain, spinal cord, bones, joints, breasts, blood vessels, and heart. Image segmentation, in medical image analysis, is usually the first step to find out some characteristics with similar color, intensity or texture so that the diagnosis could be further carried out based on these features. This paper introduces an improved C-means model to segment the MRI images. The model is based on information entropy to evaluate the segmentation results by achieving global optimization. Several contributions are significant. Firstly, Genetic Algorithm (GA) is used for achieving global optimization in this model where fuzzy C-means clustering algorithm (FCMA) is not capable of doing that. Secondly, the information entropy after segmentation is used for measuring the effectiveness of MRI image processing. Experimental results show the outperformance of the proposed model by comparing with traditional approaches.

Keywords: magnetic resonance image (MRI), c-means model, image segmentation, information entropy

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Authors: Rajendra Kumar Dubey

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Einstein’s field equations with variable cosmological term Λ are considered in the presence of viscous fluid for Bianchi type I space time. Exact solutions of Einstein’s field equations are obtained by assuming cosmological term Λ Proportional to (R is a scale factor and m is constant). We observed that the shear viscosity is found to be responsible for faster removal of initial anisotropy in the universe. The physical significance of the cosmological models has also been discussed.

Keywords: bianchi type, I cosmological model, viscous fluid, cosmological constant Λ

Procedia PDF Downloads 528

Authors: Tourab Wafa, Nemamcha Mohamed, Babouri Abdessalem

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This paper consists on an experimental and analytical characterization of the electromagnetic environment in the in the medium surrounding a circuit of two 220 Kv power lines running in parallel. The analysis presented in this paper is divided into two main parts. The first part concerns the experimental study of the behavior of the electric field and magnetic field generated by the selected double-circuit at ground level (0 m). While the second part simulate and calculate the fields profiles generated by the both lines at different levels above the ground, from (0 m) to the level close to the lines conductors (20 m above the ground) using the electrostatic and magneto-static modules of the COMSOL multi-physics software. The implications of the results are discussed and compared with the ICNIRP reference levels for occupational and non occupational exposures.

Keywords: HV power lines, low frequency electromagnetic fields, electromagnetic compatibility, inductive and capacitive coupling, standards

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Authors: Rahul Singha, D. Vakula

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This paper presents a corrugated antipodal vivaldi antenna with improved performance by using negative index metamaterial (NIM) of the Archimedean spiral design. A single layer NIM piece is placed perpendicular middle of the two arm of the proposed antenna. The antenna size is 30×60×0.787 mm3 operating at 8GHz. The simulated results of NIM corrugated antipodal vivaldi antenna show that the gain and directivity has increased up to 1.2dB and 1dB respectively. The HPBW is increased by 90 with the reflection coefficient less than ‒10 dB from 4.7 GHz to 11 GHz for UWB application.

Keywords: Negative Index Metamaterial (NIM), Ultra Wide Band (UWB), Half Power Beam Width (HPBW), vivaldi antenna

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Authors: Wen-Yu Lin, Yi-Ching Chung, Tzyy-Rong Jinn

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It is well known that enterovirus 71 (EV71) causes recurring outbreaks of hand, foot and mouth disease (HFMD) and encephalitis leading to complications or death in young children. And, several HFMD of EV71 with high mortalities occurred in Asia countries, such as Malaysia (1997), Taiwan (1998) and China (2008). Thus, more effective antiviral drugs are needed to prevent or reduce EV71-related complications. As reported, interferon-α protects mice from lethal EV71 challenge by the modulation of innate immunity and then degrade enterovirus protease 3Cᵖʳᵒ. On the other side, pleconaril by targeting enterovirus VP1 protein and then block virus entry and attachment. Thus, the aim of this study was to evaluate the synergistic antiviral activity of interferon-α and pleconaril against enterovirus 71 infection. In a preliminary study showed that pleconaril at concentrations of 50, 100 and 300 µg/mL reduced EV71-induced CPE to 52.0 ± 2.5%, 40.2 ± 3.5% and 26.5 ± 1.5%, respectively, of that of the EV71-infected RD control cells (taken as 100%). Notably, 1000 IU/mL of interferon-α in combination with pleconaril at concentrations of 50, 100 and 300µg/mL suppressed EV71-induced CPE by 30.2 ± 3.8%, 16.5 ± 1.3% and 2.8 ± 2.0%, respectively, of that of the pleconaril alone treated with the infected RD cells. These results indicated that interferon-α 1000 IU/mL combination with pleconaril (50, 100 and 300µg/mL) inhibited EV71-induced CPE more effectively than treated with pleconaril alone in the infected RD cells.

Keywords: enterovirus 71, interferon-α, pleconaril, RD cells

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Authors: Kheireddine El-Boubbou

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Drug delivery to target human acute myeloid leukemia (AML) using a nanoparticulate chemotherapeutic formulation that can deliver drugs selectively to AML cancer is hugely needed. In this work, we report the development of a nanoformulation made of polymeric-stabilized multifunctional magnetic iron oxide nanoparticles (PMNP) loaded with the anticancer drug Doxorubicin (Dox) as a promising drug carrier to treat AML. Dox@PMNP conjugates simultaneously exhibited high drug content, maximized fluorescence, and excellent release properties. Nanoparticulate uptake and cell death following addition of Dox@PMNPs were then evaluated in different types of human AML target cells, as well as on normal human cells. While the unloaded MNPs were not toxic to any of the cells, Dox@PMNPs were found to be highly toxic to the different AML cell lines, albeit at different inhibitory concentrations (IC₅₀ values), but showed very little toxicity towards the normal cells. In comparison, free Dox showed significant potency concurrently to all the cell lines, suggesting huge potentials for the use of Dox@PMNPs as selective AML anticancer cargos. Live confocal imaging, fluorescence and electron microscopy confirmed that Dox is indeed delivered to the nucleus in relatively short periods of time, causing apoptotic cell death. Importantly, this targeted payload may potentially enhance the effectiveness of the drug in AML patients and may further allow physicians to image leukemic cells exposed to Dox@PMNPs using MRI.

Keywords: magnetic nanoparticles, drug delivery, acute myeloid leukemia, iron oxide, cancer nanotherapy

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Authors: Md. S. Ansari, S. S. Motsa

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In this paper, an analysis has been made on the flow of non-Newtonian viscoelastic nanofluid over a linearly stretching sheet under the influence of uniform magnetic field. Heat transfer characteristics is analyzed taking into the effect of nonlinear radiation and non-uniform heat source/sink. Transport equations contain the simultaneous effects of Brownian motion and thermophoretic diffusion of nanoparticles. The relevant partial differential equations are non-dimensionalized and transformed into ordinary differential equations by using appropriate similarity transformations. The transformed, highly nonlinear, ordinary differential equations are solved by spectral local linearisation method. The numerical convergence, error and stability analysis of iteration schemes are presented. The effects of different controlling parameters, namely, radiation, space and temperature-dependent heat source/sink, Brownian motion, thermophoresis, viscoelastic, Lewis number and the magnetic force parameter on the flow field, heat transfer characteristics and nanoparticles concentration are examined. The present investigation has many industrial and engineering applications in the fields of coatings and suspensions, cooling of metallic plates, oils and grease, paper production, coal water or coal–oil slurries, heat exchangers’ technology, and materials’ processing and exploiting.

Keywords: magnetic field, nonlinear radiation, non-uniform heat source/sink, similar solution, spectral local linearisation method, Rosseland diffusion approximation

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Authors: Yusha'u Shu'aibu Baraya, Kah Keng Wong, Nik Soriani Yaacob

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Strobilanthes crispus (S. crispus), is a Malaysian herb locally known as ‘Pecah kaca’ or ‘Jin batu’ which have demonstrated potent anticancer effects in both in vitro and in vivo models. In particular, S. crispus subfraction (SCS) significantly reduced tumor growth in N-methyl-N-Nitrosourea-induced breast cancer rat model. However, there is paucity of information on the effects of SCS in breast cancer metastasis. Thus, in this study, the antimetastatic effects of SCS (100 mg/kg) was investigated following 30 days of treatment in 4T1-induced mammary tumor (n = 5) model. The response to treatment was assessed based on the outcome of the tumour growth, body weight and hematological parameters. The results demonstrated that tumor bearing mice treated with SCS (TM-S) had significant (p<0.05) reduction in the mean tumor number and tumor volume as well as tumor weight compared to the tumor bearing mice (TM), i.e. tumor untreated group. Also, there was no secondary tumor formation or tumor-associated lesions in the major organs of TM-S compared to the TM group. Similarly, comparable body weights were observed among the TM-S, normal (uninduced) mice treated with SCS and normal (untreated/control) mice (NM) groups compared to the TM group (p<0.05). Furthermore, SCS administration does not cause significant changes in the hematological parameters as compared to the NM group, which indicates no sign of anemia and toxicity related effects. In conclusion, SCS significantly inhibited the overall tumor growth and metastasis in 4T1-induced breast cancer mouse model suggesting its promising potentials as therapeutic agent for breast cancer treatment.

Keywords: 4T1-cells, breast cancer, metastasis, Strobilanthes crispus

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Authors: Alouaoui Redha, Ferhat Samira, Bouaziz Mohamed Najib

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In this work, we examine the thermal radiation effect on heat and mass transfer in steady laminar boundary layer flow of an incompressible viscous micropolar fluid over a vertical plate, with the presence of a magnetic field. Rosseland approximation is applied to describe the radiative heat flux in the energy equation. The resulting similarity equations are solved numerically. Many results are obtained and representative set is displayed graphically to illustrate the influence of the various parameters on different profiles. The conclusion is drawn that the flow field, temperature, concentration and microrotation as well as the skin friction coefficient and the both local Nusselt and local Sherwood numbers are significantly influenced by Magnetic parameter, material parameter and thermal radiation parameter.

Keywords: MHD, micropolar fluid, thermal radiation, heat and mass transfer, boundary layer

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Authors: Sara El-Hanboushy, Hayam Lotfy, Yasmin Fayez, Engy Shokry, Mohammed Abdelkawy

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Simple, specific, accurate and precise spectrophotometric methods are developed and validated for simultaneous determination of pseudoephedrine sulphate (PSE) and loratadine (LOR) in combined dosage form based on spectral analysis technique. Pseudoephedrine (PSE) in binary mixture could be analyzed either by using its resolved zero order absorption spectrum at its λ max 256.8 nm after subtraction of LOR spectrum or in presence of LOR spectrum by absorption correction method at 256.8 nm, dual wavelength (DWL) method at 254nm and 273nm, induced dual wavelength (IDWL) method at 256nm and 272nm and ratio difference (RD) method at 256nm and 262 nm. Loratadine (LOR) in the mixture could be analyzed directly at 280nm without any interference of PSE spectrum or at 250 nm using its recovered zero order absorption spectrum using constant multiplication(CM).In addition, simultaneous determination for PSE and LOR in their mixture could be applied by induced amplitude modulation method (IAM) coupled with amplitude multiplication (PM).

Keywords: dual wavelength (DW), induced amplitude modulation method (IAM) coupled with amplitude multiplication (PM), loratadine, pseudoephedrine sulphate, ratio difference (RD)

Procedia PDF Downloads 321

Authors: Xiao Zhou, Jianlin Cheng

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A single amino acid mutation can have a significant impact on the stability of protein structure. Thus, the prediction of protein stability change induced by single site mutations is critical and useful for studying protein function and structure. Here, we presented a deep learning network with the dropout technique for predicting protein stability changes upon single amino acid substitution. While using only protein sequence as input, the overall prediction accuracy of the method on a standard benchmark is >85%, which is higher than existing sequence-based methods and is comparable to the methods that use not only protein sequence but also tertiary structure, pH value and temperature. The results demonstrate that deep learning is a promising technique for protein stability prediction. The good performance of this sequence-based method makes it a valuable tool for predicting the impact of mutations on most proteins whose experimental structures are not available. Both the downloadable software package and the user-friendly web server (DNpro) that implement the method for predicting protein stability changes induced by amino acid mutations are freely available for the community to use.

Keywords: bioinformatics, deep learning, protein stability prediction, biological data mining

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Authors: Jixiao Tao, Xiaoqiao He

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The present study deals with the finite element (FE) analysis of thermally-induced bistable plate using various plate elements. The quadrilateral plate elements include the 4-node conforming plate element based on the classical laminate plate theory (CLPT), the 4-node and 9-node Mindlin plate element based on the first-order shear deformation laminated plate theory (FSDT), and a displacement-based 4-node quadrilateral element (RDKQ-NL20). Using the von-Karman’s large deflection theory and the total Lagrangian (TL) approach, the nonlinear FE governing equations for plate under thermal load are derived. Convergence analysis for four elements is first conducted. These elements are then used to predict the stable shapes of thermally-induced bistable plate. Numerical test shows that the plate element based on FSDT, namely the 4-node and 9-node Mindlin, and the RDKQ-NL20 plate element can predict two stable cylindrical shapes while the 4-node conforming plate predicts a saddles shape. Comparing the simulation results with ABAQUS, the RDKQ-NL20 element shows the best accuracy among all the elements.

Keywords: Bistable, finite element method, geometrical nonlinearity, quadrilateral plate elements

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Authors: Mohaya Farzin, Shahin Hassanpour, Morteza Zendehdel, Bita Vazir, Ahmad Asghari

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Aim: There are several differences between birds and mammals in terms of food intake regulation. Therefore, this study aimed to investigate the effects of the intracerebroventricular (ICV) injection of spexin and its interaction with nitric oxide, serotonin, and corticotropin receptors on central food intake regulation in broiler chickens. Materials and Methods: In experiment 1, chickens received ICV injection of saline, PCPA (p-chlorophenyl alanine,1.25 µg), spexin, and PCPA+spexin. In experiments 2-7, 8-OH-DPAT (5-HT1A agonist, 15.25 nmol), SB-242084 (5-HT2C receptor antagonist, 1.5µg), L-arginine (Precursor of nitric oxide, 200 nmol), L-NAME (nitric oxide synthetase inhibitor, 100 nmol), Astressin-B (CRF1/CRF2 receptor antagonist, 30 µg) and Astressin2-B (CRF2 receptor antagonist, 30 µg) were injected to chickens instead of the PCPA. Then, food intake was measured until 120 minutes after the injection. Results: Spexin significantly decreased food consumption (P<0.05). Concomitant injection of SB-242084+spexin attenuated spexin-induced hypophagia (P<0.05). Co-injection of L-arginine+spexin enhanced spexin-induced hypophagia, and this effect was reversed by L-NAME (P<0.05). Also, concomitant injection of Astressin-B + spexin or Astressin2-B + spexin enhanced spexin-induced hypophagia (P<0.05). Conclusions: Based on these observations, spexin-induced hypophagia may be mediated by nitric oxide and 5-HT2C, CRF1, and CRF2 receptors in neonatal broiler chickens.

Keywords: spexin, serotonin, corticotropin, nitric oxide, food intake, chicken

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Authors: Krzysztof Malczewski

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Magnetic Resonance Imaging (MRI) reconstruction algorithm using compressed sensing is presented in this paper. It is exhibited that the offered approach improves MR images spatial resolution in circumstances when highly undersampled k-space trajectories are applied. Compressed Sensing (CS) aims at signal and images reconstructing from significantly fewer measurements than were conventionally assumed necessary. Magnetic Resonance Imaging (MRI) is a fundamental medical imaging method struggles with an inherently slow data acquisition process. The use of CS to MRI has the potential for significant scan time reductions, with visible benefits for patients and health care economics. In this study the objective is to combine super-resolution image enhancement algorithm with CS framework benefits to achieve high resolution MR output image. Both methods emphasize on maximizing image sparsity on known sparse transform domain and minimizing fidelity. The presented algorithm considers the cardiac and respiratory movements.

Keywords: super-resolution, MRI, compressed sensing, sparse-sense, image enhancement

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Authors: Moon Ho Do, Sin-Hee Park, Jae Hyuk Lee, Kyo Hee Cho, Jae Kyung Chae, Sun Yeou Kim

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Long-term hyperglycemic conditions associated with diabetes lead to the formation of advanced glycation end-products (AGEs). Highly reactive glucose metabolites, methylglyoxal (MGO) and glyoxal (GO), induced carbonyl stress and it may induce cellular damage, cross-linking of proteins, and glycation, playing an important role in the impairment of kidney function. Small molecules that have the ability to inhibit AGE formation, and even break preformed AGEs have a beneficial impact on metabolic syndrome, diabetes, and cancer. We quantified contents of polyphenols in nuts and investigated the protective effect of nuts and polyphenols on MGO-induced cytotoxicity in porcine kidney epithelial cells (LLC-PK1). Moreover, we evaluated the inhibitory effect of AGEs formation in the presence of MGO or GO and possess the ability to break preformed AGEs. In this study, we confirmed twenty polyphenols in diverse nuts using LC-MS/MS system. Nuts and polyphenols play a protective role in LLC-PK1 cells by reducing MGO-induced cytotoxicity. They could also prevent the formation of MGO or GO-mediated AGEs and Break AGEs crosslink. It can be surmised that increased consumption of nuts would be an effective means of preventing diabetic diseases.

Keywords: advanced glycation end products, LLC-PK1, methylglyoxal, nut, polyphenol

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Authors: Nootchanat Mairuae, Walaiporn Tongjaroenbuangam, Chalisa Louicharoen Cheepsunthorn, Poonlarp Cheepsunthorn

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The aim of this study was to investigate the anti-oxidative effect, the anti-inflammatory effects, and the molecular mechanisms of okra (Abelmoschus esculentus Linn.) on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. The BV2 cells were treated with LPS in the presence or absence of okra. Reactive oxygen species (ROS) and nitric oxide (NO) production were measured using the ROS detection reagent DCF-DA and the Griess reaction, respectively. The phosphorylation levels of nuclear factor-kappa B (NF-kB) p65 was detected by Western blot assay. Treatment of BV2 microglia cells with okra was found to significantly suppress the LPS-induced inflammatory mediator NO as well as ROS compared to untreated cells. The levels of LPS-induced NF-kB p65 phosphorylation were significantly decreased following okra treatment too. These results show that okra exerts anti-oxidative and anti-inflammatory effects in LPS-stimulated BV2 microglial cells by suppressing the NF-κB pathway. This suggests okra might be a valuable agent for treatment of anti-neuroinflammatory diseases mediated by microglial cells.

Keywords: Abelmoschus esculentus Linn, microglia, neuroinflammation, reactive oxygen spicy

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Authors: R. A. Shahmiri, O. Standard, J. Hart, C. C. Sorrell

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Yttrium stabilized tetragonal zirconium polycrystalline (Y-TZP) has been used as a dental biomaterial. The strength and toughness of zirconia can be accounted for by its toughening mechanisms, such as crack deflection, zone shielding, contact shielding, and crack bridging. Prevention of crack propagation is of critical importance in high-fatigue situations, such as those encountered in mastication and para-function. However, the poor translucency of Y-TZP means that it may not meet the aesthetic requirements due to its white/grey appearance in polycrystalline form. To improve optical property of the Zirconia, precise evaluation of its refractive index is of significance. Zirconia`s optical properties need to be studied more in depth. Number of studies assumed, scattered light is isotropically distributed over all angles from biological media when defining optical parameters. Nevertheless, optical behaviour of real biological material depends on angular scattering of light by anisotropy material. Therefore, the average cosine of the scattering angle (which represent recovery phase function in the scattering angular distribution) usually characterized by anisotropy material. It has been identified that yttrium anti-sites present in the space charge layer have no significant role in the absorption of light in the visible range. Addition of cation dopant to polycrystalline zirconia results in segregate to grain boundaries and grain growth. Intrinsic and extrinsic properties of ZrO2 and their effect on optical properties need to be investigated. Intrinsic properties such as chemical composition, defect structure (oxygen vacancy), phase configuration (porosity, second phase) and distribution of phase need to be studied to comprehend their effect on refraction index, absorption/reflection and scattering. Extrinsic properties such as surface structure, thickness, underlying tooth structure, cement layer (type, thickness), and light source (natural, curing, artificial) of ZrO2 need to be studied to understand their effect on colour and translucency of material. This research reviewed effect of stabilization of tetragonal zirconia on optical property of zirconia for dental application.

Keywords: optical properties, zirconia dental biomaterial, chemical composition, phase composition

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Authors: Subodh Kumar, Sanjeev Kumar Sharma, Gaurav Kaushik, Pramod Avti, Phulen Sarma, Bikash Medhi, Krishan Lal Khanduja

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Background: It is well known that cigarette smoke is one of the causative factors in various lung diseases especially cancer. Carcinogens and oxidant molecules present in cigarette smoke not only damage the cellular constituents (lipids, proteins, DNA) but may also regulate the molecular pathways involved in inflammation and cancer. Continuous oxidative stress caused by the constituents of cigarette smoke leads to higher PhospholipaseA₂ (PLA₂) activity, resulting in elevated levels of secondary metabolites whose role is well defined in cancer. To reduce the burden of chronic inflammation as well as oxidative stress, and higher levels of secondary metabolites, we checked the curative potential of PLA₂ inhibitor Bromoenol Lactone (BEL) during continuous exposure of cigarette smoke condensate (CSC). Aim: To check the therapeutic potential of Bromoenol Lactone (BEL), an inhibitor of PhospholipaseA₂s, in pathways of CSC-induced changes in type I and type II alveolar epithelial cells. Methods: Effect of BEL on CSC-induced PLA2 activity were checked using colorimetric assay, cellular toxicity using cell viability assay, membrane integrity using fluorescein di-acetate (FDA) uptake assay, reactive oxygen species (ROS) levels and apoptosis markers through flow cytometry, and cellular regulation using MAPKinases levels, in lung epithelium. Results: BEL significantly mimicked CSC-induced PLA₂ activity, ROS levels, apoptosis, and kinases level whereas improved cellular viability and membrane integrity. Conclusions: Current observations revealed that BEL may be a potential therapeutic agent during Cigarette smoke-induced anomalies in lung epithelium.

Keywords: cigarette smoke condensate, phospholipase A₂, oxidative stress, alveolar epithelium, bromoenol lactone

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Authors: P. Pistelok

Abstract:

The article presents the concept of an electromagnetic circuit generator with permanent magnets mounted on the surface rotor core designed for single phase work. Computation field-circuit model was shown. The spectrum of time course of voltages in the idle work was presented. The cross section with graphically presentation of magnetic induction in particular parts of electromagnetic circuits was presented. Distribution of magnetic induction at the rated load point for each phase were shown. The time course of voltages and currents for each phases for rated power were displayed. An analysis of laboratory results and measurement of load characteristics of the generator was discussed. The work deals with three electromagnetic circuits of generators with permanent magnet where output voltage characteristics versus rated power were expressed.

Keywords: permanent magnet generator, permanent magnets, vibration, course of torque, single phase work, asymmetrical three phase work

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Authors: Bang-Fuh Chen, Chih-Chun Chu

Abstract:

The flow induced cylinder vibration or earthquake-induced cylinder motion are moving in an arbitrary direction with time. The phenomenon of flow across cylinder is highly nonlinear and a linear-superposition of flow pattern across separated oscillating direction of cylinder motion is not valid to obtain the flow pattern across a cylinder oscillating in multiple directions. A novel finite difference scheme is developed to simulate the viscous flow across an arbitrary moving circular cylinder and we call this a complete 2D (two-dimensional) flow-cylinder interaction. That is, the cylinder is simultaneously oscillating in x- and y- directions. The time-dependent domain and meshes associated with the moving cylinder are mapped to a fixed computational domain and meshes, which are time independent. The numerical results are validated by several bench mark studies. Several examples are introduced including flow across steam-wise, transverse oscillating cylinder and flow across rotating cylinder and flow across arbitrary moving cylinder. The Morison’s formula can not describe the complex interaction phenomenon between cross flow and oscillating circular cylinder. And the completed 2D computational fluid dynamic analysis should be made to obtain the correct hydrodynamic force acting on the cylinder.

Keywords: 2D cylinder, finite-difference method, flow-cylinder interaction, flow induced vibration

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Authors: Junkyeong Kim, Jooyoung Park, Aoqi Zhang, Seunghee Park

Abstract:

The tensile force of Pre-Stressed Concrete (PSC) girder is the most important factor for evaluating the performance of PSC girder bridges. To measure the tensile force of PSC girder, several NDT methods were studied. However, conventional NDT method cannot be applied to the real-size PSC girder because the PS tendons could not be approached. To measure the tensile force of real-size PSC girder, this study proposed embedded EM sensor based tensile force estimation method. The embedded EM sensor could be installed inside of PSC girder as a sheath joint before the concrete casting. After curing process, the PS tendons were installed, and the tensile force was induced step by step using hydraulic jacking machine. The B-H loop was measured using embedded EM sensor at each tensile force steps and to compare with actual tensile force, the load cell was installed at each end of girder. The magnetization energy loss, that is the closed area of B-H loop, was decreased according to the increase of tensile force with regular pattern. Thus, the tensile force could be estimated by the tracking the change of magnetization energy loss of PS tendons. Through the experimental result, the proposed method can be used to estimate the tensile force of the in-situ real-size PSC girder bridge.

Keywords: tensile force estimation, embedded EM sensor, magnetization energy loss, PSC girder

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Authors: Asma Mosbah, Hanane Khither, Kamelia Mosbah, Noreddine Kacem Chaouche, Mustapha Benboubetra

Abstract:

In the present investigation, total oil (TO) and its neutral lipid fraction (NLF) extracted from the seed of the well know studied medicinal plant Nigella sativa were tested for their therapeutically effect on alcohol-induced liver injury in rat model. Male Albino rats were divided into five groups of eight animals each and fed a Lieber–DeCarli liquid diet containing 5% ethanol for experimental groups and dextran for control group, for a period of six weeks. Afterwards, rats received, orally, treatments with Nigella sativa extracts (TO, NLF) and N- acetylcysteine (NAC) as a positive control for four weeks. Activities of antioxidant enzymes; superoxide dismutase (SOD) and catalase (CAT), as well as malondialdehyde (MDA) and reduced glutathione (GSH). Biochemical parameters for kidney and liver functions, in treated and non treated rats, were evaluated throughout the time course of an experiment. Liver histological changes were taken into account. Enzymatic activities of both SOD and CAT increased significantly in rats treated with NLF and TO. While MDA level decreased in TO and NLF treated rats, GSH level increased significantly in TO and NLF treated rats. We noted equally a decrease in liver enzymes AST, ALT, and ALP. Microscopic observation of slides from the liver of ethanol treated rats showed a severe hepatotoxicity with lesions. Treatment with fractions leads to an improvement in liver lesions and a marked reduction in necrosis and infiltration. As a conclusion, both extracts of Nigella sativa seeds, TO and NLF, possess an important therapeutic protective potential against ethanol-induced hepatotoxicity in rats.

Keywords: alcohol-induced hepatotoxicity, antioxidant enzymes, Nigella sativa seeds, oil fractions

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Authors: Hossein Panahi, Firouz Fallahi, Sima Nasibparast

Abstract:

Background & Aim: Unnecessary growth in health expenditures of developing countries in recent decades, and also the importance of physicians’ behavior in health market, have made the theory of physician-induced demand (PID) as one of the most important issues in health economics. Therefore, the main objective of this study is to investigate the hypothesis of induced demand among mental patients who receive services from either psychologists or psychiatrists in East Azerbaijan province. Methods: Using data from questionnaires in 2020 and employing the theoretical model of Jaegher and Jegers (2000) and hierarchical linear modeling (HLM), this study examines the PID hypothesis of selected psychologists and psychiatrists. The sample size of the study, after removing the questionnaires with missing data, is 45 psychologists and 203 people of their patients, as well as 30 psychiatrists and 160 people of their patients. Results: The results show that, although psychiatrists are ‘profit-oriented physicians’, there is no evidence of inducing unnecessary demand by them (PID), and the difference between the behavior of employers and employee doctors is due to differences in practice style. However, with regard to psychologists, the results indicate that they are ‘profit-oriented’, and there is a PID effect in this sector. Conclusion: According to the results, it is suggested that in order to reduce competition and eliminate the PID effect, the admission of students in the field of psychology should be reduced, patient information on mental illness should be increased, and government monitoring and control over the national health system must be increased.

Keywords: physician-induced demand, national health system, hierarchical linear modeling methods, multilevel modela

Procedia PDF Downloads 136

Authors: Patience Muchini, Electdom Matandiroya, Emmanuel Mashonjowa

Abstract:

A ground-end manifestation of space weather phenomena is known as geomagnetically induced currents (GICs). GICs flow along the electric power transmission cables connecting the transformers and between the grounding points of power transformers during significant geomagnetic storms. Geomagnetically induced currents have been studied in other regions and have been noted to affect the power grid network. In Zimbabwe, grid failures have been experienced, but it is yet to be proven if these failures have been due to GICs. The purpose of this paper is to characterize geomagnetically induced currents with a power grid network. This paper analyses data collected, which is geomagnetic data, which includes the Kp index, DST index, and the G-Scale from geomagnetic storms and also analyses power grid data, which includes reactive power, relay tripping, and alarms from high voltage substations and then correlates the data. This research analysis was first theoretically analyzed by studying geomagnetic parameters and then experimented upon. To correlate, MATLAB was used as the basic software to analyze the data. Latitudes of the substations were also brought into scrutiny to note if they were an impact due to the location as low latitudes areas like most parts of Zimbabwe, there are less severe geomagnetic variations. Based on theoretical and graphical analysis, it has been proven that there is a slight relationship between power system failures and GICs. Further analyses can be done by implementing measuring instruments to measure any currents in the grounding of high-voltage transformers when geomagnetic storms occur. Mitigation measures can then be developed to minimize the susceptibility of the power network to GICs.

Keywords: adverse space weather, DST index, geomagnetically induced currents, KP index, reactive power

Procedia PDF Downloads 114

Authors: Abdul Soofi, Katherine Wolf, Egon Ranghini, Gregory Dressler

Abstract:

Obesity and its associated complications, such as insulin resistance and non-alcoholic fatty liver disease, are reaching epidemic proportions. In mice, the TGF-β superfamily is implicated in the regulation of white and brown adipose tissues differentiation. The Kielin/Chordin-like Protein (KCP) is a secreted regulator of the TGF-β superfamily pathways that can inhibit both TGF-β and Activin signals while enhancing the Bone Morphogenetic protein (BMP) signaling. However, the effects of KCP on metabolism and obesity have not been studied in animal models. Thus, we examined the effects of KCP loss or gain of function in mice that were maintained on either a regular or a high fat diet. Loss of KCP sensitized mice to obesity and associated complications such as hepatic steatosis and glucose intolerance. In contrast, transgenic mice that expressed KCP in the kidney, liver and adipose tissues were resistant to developing high fat diet induced obesity and had significantly reduced white adipose tissue. KCP over-expression was able to shift the pattern of Smad signaling in vivo, to increase the levels of P-Smad1 and decrease P-Smad3, resulting in resistance to high fat diet induced hepatic steatosis and glucose intolerance. In aging mice, loss of KCP promoted liver pathology even when mice were fed a normal diet. The data demonstrate that shifting the TGF-β superfamily signaling with a secreted inhibitor or enhancer can alter the physiology of adipose tissue to reduce obesity and can inhibit the initiation and progression of hepatic steatosis to significantly reduce the effects of high fat diet induced metabolic disease.

Keywords: adipose tissue, KCP, obesity, TGF-β, BMP, hepatic steatosis, metabolic syndrome

Procedia PDF Downloads 353