Search results for: j2 effect

Authors: Junhong Feng, Wenyu Lu, Xinhong Cheng, Li Zheng, Yuehui Yu

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The effects of proton irradiation on the properties of gate oxide were evaluated by monitoring the static parameters (such as threshold voltage and on-resistance) and dynamic parameters (Miller plateau time) of 1700V SiC VDMOS before and after proton irradiation. The incident proton energy was 3MeV, and the doses were 5 × 10¹² P / cm², 1 × 10¹³ P / cm², respectively. The results show that the threshold voltage of MOS exhibits negative drift under proton irradiation, and the near-interface traps in the gate oxide layer are occupied by holes generated by the ionization effect of irradiation, thus forming more positive charges. The basis for selecting TMiller is that the change time of Vgs is the time when Vds just shows an upward trend until it rises to a stable value. The degradation of the turn-off time of the Miller platform verifies that the capacitance Cgd becomes larger, reflecting that the gate oxide layer is introduced into the trap by the displacement effect caused by proton irradiation, and the interface state deteriorates. As a more sensitive area in the irradiation process, the gate oxide layer will be optimized for its parameters (such as thickness, type, etc.) in subsequent studies.

Keywords: SiC VDMOS, proton radiation, Miller time, gate oxide

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Authors: Miroslava Zelinkova, Marcela Ondova

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Fly ash (FA) thanks to the significant presence of SiO2 and Al2O3 as the main components is a potential raw material for geopolymers production. Mechanical activation is a method for improving FA reactivity and also the porosity of final mixture; those parameters can be analysed through sorption properties. They have direct impact on the durability of fly ash based geopolymer mortars. In the paper, effect of FA fineness on sorption properties of geopolymers based on sodium silicate, as well as relationship between fly ash fineness and apparent density, compressive and flexural strength of geopolymers are presented. The best results in the evaluated area reached the sample H1, which contents the highest portion of particle under 20μm (100% of GFA). The interdependence of individual tested properties was confirmed for geopolymer mixtures corresponding to those in the cement based mixtures: higher is portion of fine particles < 20μm, higher is strength, density and lower are sorption properties. The compressive strength as well as sorption parameters of the geopolymer can be reasonably controlled by grinding process and also ensured by the higher share of fine particle (to 20μm) in total mass of the material.

Keywords: alkali activation, geopolymers, fly ash, particle fineness

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Authors: K. Al Ammari, B. G. Clarke

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Soil improvement using vibro stone column techniques consists of two main parts: (1) the installed load bearing columns of well-compacted, coarse-grained material and (2) the improvements to the surrounding soil due to vibro compaction. Extensive research work has been carried out over the last 20 years to understand the improvement in the composite foundation performance due to the second part mentioned above. Nevertheless, few of these studies have tried to quantify some of the key design parameters, namely the changes in the stiffness and stress state of the treated soil, or have consider these parameters in the design and calculation process. Consequently, empirical and conservative design methods are still being used by ground improvement companies with a significant variety of results in engineering practice. Two-dimensional finite element study to develop an axisymmetric model of a single stone column reinforced foundation was performed using PLAXIS 2D AE to quantify the effect of the vibro installation of this column in soft saturated clay. Settlement and bearing performance were studied as an essential part of the design and calculation of the stone column foundation. Particular attention was paid to the large deformation in the soft clay around the installed column caused by the lateral expansion. So updated mesh advanced option was taken in the analysis. In this analysis, different degrees of stone column lateral expansions were simulated and numerically analyzed, and then the changes in the stress state, stiffness, settlement performance and bearing capacity were quantified. It was found that application of radial expansion will produce a horizontal stress in the soft clay mass that gradually decrease as the distance from the stone column axis increases. The excess pore pressure due to the undrained conditions starts to dissipate immediately after finishing the column installation, allowing the horizontal stress to relax. Changes in the coefficient of the lateral earth pressure K ٭, which is very important in representing the stress state, and the new stiffness distribution in the reinforced clay mass, were estimated. More encouraging results showed that increasing the expansion during column installation has a noticeable effect on improving the bearing capacity and reducing the settlement of reinforced ground, So, a design method should include this significant effect of the applied lateral displacement during the stone column instillation in simulation and numerical analysis design.

Keywords: bearing capacity, design, installation, numerical analysis, settlement, stone column

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Authors: A. Kaibi, A. Guittoum, M. Hemmous, D. Martínez-Blanco, P. Gorria, J. A. Blanco, M. Kechouane

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The present work deals with the effect of Si content on the physical properties of nanostructured (Ni75Fe25)100-x Six (x=0, 3.5, 6.5, 9, 12, and 15 at %) powders elaborated by mechanical alloying for a milling time of 96 h. The microstructure, hyperfine, and magnetic properties of the powders were investigated as a function of Si content by means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Mössbauer Spectroscopy, and Vibrating Sample magnetometry (VSM). From XRD spectra, the formation of FCC disordered Ni (Fe,Si) solid solution was evidenced after 96 h. As Si content increases, the lattice parameter and the grain size decrease (from ~28 to 15 nm), while the microstrain level decreases from 0.98% to 0.65%. From SEM micrographs, we showed that powder particles become round in shape and decrease in size with increasing Si content. For all Si content, the adjustment of Mössbauer spectra confirmed the formation of a disordered ferromagnetic NiFeSi phase. From hysteresis curves, we have extracted the values of saturation magnetization and coercive field for all powders. The evolution of Ms and Hc as a function of Si content will be discussed.

Keywords: nanostructured powders, (Ni75Fe25)100-xSix alloy, microstructure, magnetic properties

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Authors: Mohammad Hemmati, Mohammad Taban, Ali Yasini

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One of the factors that can play an important role in increasing productivity is the optimal use of information technology, which in this area today has a significant role to play in computer systems of office automation in organizations and companies. Therefore, this research has been conducted with the aim of investigating the effect of the relationship between computerized systems of office automation and the productivity of employees in the municipality of Ilam city. The statistical population of this study was 110 people. Using Cochran formula, the minimum sample size is 78 people. The present research is a descriptive-looking research in terms of the type of objective view. A questionnaire was used to collect data. To assess the reliability of variables, Cornbrash’s alpha coefficient was used, which was equal to 0.85; SPSS19 and Pearson test were used to analyze the data and test the hypothesis of the research. In this research, three hypotheses of the relationship between office automation with efficiency, performance, and effectiveness were investigated. The results showed a direct and positive relationship between the office automation system and the increase in the efficiency, effectiveness, and efficiency of employees, and there was no reason to reject these hypotheses.

Keywords: efficiency, performance, effectiveness, automation

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Authors: Jae-Ho Jang, Jung-Soo Kim, Byung-Jun Kim, Dae-Geun Nam, Uoo-Chang Jung, Yoon-Suk Choi

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Low alloy steels are widely used for pressure vessels, spent fuel storage, and steam generators required to withstand the internal pressure and prevent unexpected failure in nuclear power plants, which these may suffer embrittlement by high levels of radiation and heat for a long period. Therefore, it is important to improve mechanical properties of low alloy steels for the integrity of structure materials at an early stage of fabrication. Recently, it showed that a double austenitizing and tempering (DTA) process resulted in a significant improvement of strength and toughness by refinement of prior austenite grains. In this study, it was investigated that the mechanism of improving mechanical properties according to the change of microstructure by the second fully austenitizing temperature of the DAT process for low alloy steel required the structural integrity. Compared to conventional single austenitizing and tempering (SAT) process, the tensile elongation properties have improved about 5%, DBTTs have obtained result in reduction of about -65℃, and grain size has decreased by about 50% in the DAT process conditions. Grain refinement has crack propagation interference effect due to an increase of the grain boundaries and amount of energy absorption at low temperatures. The higher first austenitizing temperature in the DAT process, the more increase the spheroidized carbides and strengthening the effect of fine precipitates in the ferrite grain. The area ratio of the dimple in the transition area has increased by proportion to the effect of spheroidized carbides. This may the primary mechanisms that can improve low-temperature toughness and elongation while maintaining a similar hardness and strength.

Keywords: double austenitizing, Ductile Brittle transition temperature, grain refinement, heat treatment, low alloy steel, low-temperature toughness

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Authors: Ali Asghar Memon

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The simulation modeling of switched reluctance (SR) machine often relies and uses the three data tables identified as static torque characteristics that include flux linkage characteristics, co energy characteristics and static torque characteristics separately. It has been noticed from the literature that the data of static torque used in the simulation model is often calculated so far the literature is concerned. This paper presents the simulation model that include the data of measured and calculated static torque separately to see its effect on instantaneous torque profile of the machine. This is probably for the first time so far the literature review is concerned that static torque from co energy information, and measured static torque directly from experiments are separately used in the model. This research is helpful for accurate modeling of switched reluctance drive.

Keywords: static characteristics, current chopping, flux linkage characteristics, switched reluctance motor

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Authors: Salma A. El-Marasy, Reham M. Abd-Elsalam, Omar A. Ahmed-Farid

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Dementia is characterized by impairments in memory and other cognitive abilities. This study aims to elucidate the possible ameliorative effect of silymarin on scopolamine-induced dementia using the object recognition test (ORT). The study was extended to demonstrate the role of cholinergic activity, oxidative stress, neuroinflammation, brain neurotransmitters and histopathological changes in the anti-amnestic effect of silymarin in demented rats. Wistar rats were pretreated with silymarin (200, 400, 800 mg/kg) or donepezil (10 mg/kg) orally for 14 consecutive days. Dementia was induced after the last drug administration by a single intraperitoneal dose of scopolamine (16 mg/kg). Then behavioral, biochemical, histopathological, and immunohistochemical analyses were then performed. Rats pretreated with silymarin counteracted scopolamine-induced non-spatial working memory impairment in the ORT and decreased acetylcholinesterase (AChE) activity, reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), restored gamma-aminobutyric acid (GABA) and dopamine (DA) contents in the cortical and hippocampal brain homogenates. Silymarin dose-dependently reversed scopolamine-induced histopathological changes. Immunohistochemical analysis showed that silymarin dose-dependently mitigated protein expression of a glial fibrillary acidic protein (GFAP) and nuclear factor kappa-B (NF-κB) in the brain cortex and hippocampus. All these effects of silymarin were similar to that of the standard anti-amnestic drug, donepezil. This study reveals that the ameliorative effect of silymarin on scopolamine-induced dementia in rats using the ORT maybe in part mediated by, enhancement of cholinergic activity, anti-oxidant and anti-inflammatory activities as well as mitigation in brain neurotransmitters and histopathological changes.

Keywords: dementia, donepezil, object recognition test, rats, silymarin, scopolamine

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Authors: Abdelmaguid Ramzy, Mohamed Bahaa

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Introduction: The effects of ovarian endometrioma on fertility outcomes with IVF have been always related to poor outcomes. Objective: To evaluate the effect of unilateral unoperated ovarian endometrioma < 2cm on the number of developing follicles and compare them with the contralateral ovary as a control. Design: Retrospective case control study. Setting: KasrEl-Aini IVF center. Patient(s): We studied 32 women with unilateral endometrioma who underwent their first IVF cycle. Methods: 32 Patients aged between 20-35 years selected for IVF who were diagnosed with one unilateral endometrioma (diameter <2 cm) and who did not undergo previous ovarian surgery were retrospectively identified. The number of follicles > 17 mm during folliculometry on the day of HCG trigger in the ovary that contained endometrioma were compared with those from the contralateral ovary. They were all hyperstimulated using long protocol with (225-300 IU) gonadotrophins. Primary outcome: The number of follicles > 17 mm during folliculometry on the day of HCG trigger. Result(s): The mean ± SD age, Day 3 serum FSH and LH were 27± 3.7 years, 5.8 ± 1.6 IU/ml and 4.5 ± 1.7 IU/ml respectively. There was no significant difference in the number of follicles > 17 mm on the day of HCG trigger in the ovary that contained endometrioma (4.4 ±2.5) and in the opposite ovary (4.5 ± 2.8) (P= 0.48). Conclusion: The presence of ovarian endometrioma in a controlled ovarian hyperstimulation cycle for IVF treatment is not associated with a reduced number of follicles > 17 mm during folliculometry on the day of HCG trigger.

Keywords: endometrioma, folliculometry, hyperstimulation, fertility

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Authors: Sungeun Hyun, Sooin Lee, Gyewan Moon

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Work-Family Conflict has been an active research area for the past decades. Work-Family Conflict harms individuals and organizations, it is ultimately expected to bring the cost of losses to the company in the long run. WFC has mainly focused on effects of organizational effectiveness and job attitude such as Job Satisfaction, Organizational Commitment, and Turnover Intention variables. This study is different from consequence variable with previous research. For this purpose, we selected the positive job attitude 'Work Engagement' as a consequence of WFC. This research has its primary research purpose in identifying the negative effects of the Work-Family Conflict, and started out from the recognition of the problem that the research on the direct relationship on the influence of the WFC on Work Engagement is lacking. Based on the COR(Conservation of resource theory) and JD-R(Job Demand- Resource model), the empirical study model to examine the negative effects of WFC with Emotional Exhaustion as the link between WFC and Work Engagement was suggested and validated. Also, it was analyzed how much Positive Psychological Capital may buffer the negative effects arising from WFC within this relationship, and the Mediated Moderation model controlling the indirect effect influencing the Work Engagement by the Positive Psychological Capital mediated by the WFC and Emotional Exhaustion was verified. Data was collected by using questionnaires distributed to 500 employees engaged manufacturing, services, finance, IT industry, education services, and other sectors, of which 389 were used in the statistical analysis. The data are analyzed by statistical package, SPSS 21.0, SPSS macro and AMOS 21.0. The hierarchical regression analysis, SPSS PROCESS macro and Bootstrapping method for hypothesis testing were conducted. Results showed that all hypotheses are supported. First, WFC showed a negative effect on Work Engagement. Specifically, WIF appeared to be on more negative effects than FIW. Second, Emotional exhaustion found to mediate the relationship between WFC and Work Engagement. Third, Positive Psychological Capital showed to moderate the relationship between WFC and Emotional Exhaustion. Fourth, the effect of mediated moderation through the integration verification, Positive Psychological Capital demonstrated to buffer the relationship among WFC, Emotional Exhastion, and Work Engagement. Also, WIF showed a more negative effects than FIW through verification of all hypotheses. Finally, we discussed the theoretical and practical implications on research and management of the WFC, and proposed limitations and future research directions of research.

Keywords: emotional exhaustion, positive psychological capital, work engagement, work-family conflict

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Authors: S. Nurdiana, A. S. Nor Haziqah, M. K. Nur Ezwa Khairunnisa, S. Nurul Izzati, Y. Siti Amna M. J. Norashirene, I. Nur Hilwani

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Azadirachta excelsa or locally known as sentang are frequently used as a traditional medicine by diabetes patients in Malaysia. However, less attention has been given to their toxicity effect. Thus, the study is an attempt to examine the protective effect of A. excelsa on the pancreas and to determine possible toxicity mediated by the extract. Diabetes was induced experimentally in rats by high-fat-diet for 16 weeks followed by intraperitoneal injection of streptozotocin at dosage of 35 mg/kg of body weight. Declination of the fasting blood glucose level was observed after continuous administration of A. excelsa for 14 days twice daily. This is due to the refining structure of the pancreas. However, surprisingly, the plant extract reduced the leukocytes, erythrocytes, hemoglobin, MCHC and lymphocytes. In addition, the rat treated with the plant extract exhibited increment in AST and eosinocytes level. Overall, the finding shows that A. excelsa possesses antidiabetic activity by improving the structure of pancreatic islet of Langerhans but involved in ameliorating of hematology and biochemical parameters.

Keywords: Azadirachta excelsa, diabetes, pancreas, hemato-biochemical parameters

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Authors: Naureen Naeem, M. S. Aslam

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Chia seeds found to be a rich source of dietary fiber contain oil which is high in omega 6 and omega 3 fatty acids and helpful in the control of cardiovascular diseases. Owing to its spectacular significance, present research had been designed to explore its effect on cholesterol level of the individuals after consumption of chia seed oil supplemented ice cream. The project was designed in such a manner that fat of ice cream was replaced with chia seed oil in different proportions i.e., 25%, 50%, 75%, 100%. After physico-chemical and sensory evaluation of ice cream, best treatment was selected and used for efficacy trials. After baseline line study and thorough inclusion criteria 10 individuals were selected and divided into two groups. One group treated as control and the other was given chia seed oil supplemented l(50%) ice cream. Significant decrease in cholesterol level was observed in the treated group. 18% decrease in cholesterol level was observed at 40th day followed by 8% at 20th day. Similarly 20% decrease in LDL cholesterol with 14% increase in HDL cholesterol. It was recommended that further trials be conducted with sophisticated techniques to completely replace saturated fat in ice cream with unsaturated fats and to study its effect in hyperglycemia and oxidative stress.

Keywords: hypercholesterolemia, chia seed oil, HDL, triglycerides

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Authors: Mohamed Gomaa Mohamed

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Type of study: Observational cross section study. Background and purpose: Forward head posture (FHP) is a common sagittal faulty posture with anterior head translation relative to vertical posture line. FHP related to temporomandibular joint dysfunctions, neck pain and headache. Sports persons usually overuse one side of the body in training and playing leading to postural imbalance, yet the effect of playing football or bodybuilding on measurements of FHP has never been studied. Participants: Thirty six subjects divided into 3 groups of 12 football players, 12 body builders and 12 students. Method: FHP severity was assessed by measuring the craniovertebral (CVA) and gaze angles, using the photogrammetric method. Photos were taken from right side of subjects while assuming standing position. Analysis of variance was used to assess angles difference between the three groups. Results: No significant differences were found in CVA and gaze angles between the three groups (P > 0.05). Conclusion: Playing football or body building doesn't impose significant FHP.

Keywords: craniovertebral angle, gaze angle, football, body building

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Authors: Umair Rashid

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Normally softmax loss is used as the supervision signal in face recognition (FR) system, and it boosts the separability of features. In the last two years, a number of techniques have been proposed by reformulating the original softmax loss to enhance the discriminating power of Deep Convolutional Neural Networks (DCNNs) for FR system. To learn angularly discriminative features Cosine-Margin based softmax has been adjusted as monotonically decreasing angular function, that is the main challenge for angular based softmax. On that issue, we propose monotonically decreasing element for Cosine-Margin based softmax and also, we discussed the effect of different monotonically decreasing parameters on angular Margin softmax for FR system. We train the model on publicly available dataset CASIA- WebFace via our proposed monotonically decreasing parameters for cosine function and the tests on YouTube Faces (YTF, Labeled Face in the Wild (LFW), VGGFace1 and VGGFace2 attain the state-of-the-art performance.

Keywords: deep convolutional neural networks, cosine margin face recognition, softmax loss, monotonically decreasing parameter

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Authors: Ekaterina Zubkova, Irina Beloglazova, Iurii Stafeev, Konsyantin Dergilev, Yelena Parfyonova, Mikhail Menshikov

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Mesenchymal stromal cells from adipose tissue (MSC) currently are widely used in regenerative medicine to restore the function of damaged tissues, but that is significantly hampered by their heterogeneity. One of the modern approaches to overcoming this obstacle is the polarization of cell subpopulations into a specific phenotype under the influence of cytokines and other factors that activate receptors and signal transmission to cells. We polarized MSC with factors affecting the inflammatory signaling and functional properties of cells, followed by verification of their expression profile and ability to affect the polarization of macrophages. RT-PCR evaluation showed that cells treated with LPS, interleukin-17, tumor necrosis factor α (TNF α), primarily express pro-inflammatory factors and cytokines, and after treatment with polyninosin polycytidic acid and interleukin-4 (IL4) anti-inflammatory factors and some proinflammatory factors. MSC polarized with pro-inflammatory cytokines showed a more robust pro-angiogenic effect in fibrin gel bead 3D angiogenesis assay. Further, we evaluated the possibility of paracrine effects of MSCs on the polarization of intact macrophages. Polarization efficiency was assesed by expression of M1/M2 phenotype markers CD80 and CD206. We showed that conditioned media from MSC preincubated in the presence of IL-4 cause an increase in CD206 expression similar to that observed in M2 macrophages. Conditioned media from MSC polarized in the presence of LPS or TNF-α increased the expression of CD80 antigen in macrophages, similar to that observed in M1 macrophages. In other cases, a pronounced paracrine effect of MSC on the polarization of macrophages was not detected. Thus, our study showed that the polarization of MSC along the pro-inflammatory or anti-inflammatory pathway allows us to obtain cell subpopulations that have a multidirectional modulating effect on the polarization of macrophages. (RFBR grants 20-015-00405 and 18-015-00398.)

Keywords: angiogenesis, cytokines, mesenchymal, polarization, inflammation

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Authors: Farid Habibi Tanha, Hawati Janor, Mojtaba Jahanbazi

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The purpose of this study is to examine the effect of asymmetric information on the composition of capital inflows. This study uses the stock market microstructure to capture the asymmetric information. Such an approach allows one to capture the level and extent of the asymmetric information from a firm’s perspective. This study focuses on the two-dimensional measure of the market microstructure in capturing asymmetric information. The composition of capital inflows is measured by running six models simultaneously. By employing the panel data technique, the main finding of this research shows an increase in the asymmetric information of the stock market, in any of the two dimensions of width and depth. This leads to the reduction of foreign investments in both forms of foreign portfolio investment (FPI) and foreign direct investment (FDI), while the reduction in FPI is higher than that of the FDI. The significant effect of asymmetric information on capital inflows implicitly suggests for policymakers to control the changes of foreign capital inflows through transparency in the level of the market.

Keywords: capital flows composition, asymmetric information, stock market microstructure, foreign portfolio investment, foreign direct investment

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Authors: Arash Dalili, Hamed Tahmouressi, Mina Hoorfar

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Advances in lab-on-a-chip (LOC) devices have led to significant advances in the manipulation, separation, and isolation of particles and cells. Among the different active and passive particle manipulation methods, dielectrophoresis (DEP) has been proven to be a versatile mechanism as it is label-free, cost-effective, simple to operate, and has high manipulation efficiency. DEP has been applied for a wide range of biological and environmental applications. A popular form of DEP devices is the continuous manipulation of particles by using co-planar slanted electrodes, which utilizes a sheath flow to focus the particles into one side of the microchannel. When particles enter the DEP manipulation zone, the negative DEP (nDEP) force generated by the slanted electrodes deflects the particles laterally towards the opposite side of the microchannel. The lateral displacement of the particles is dependent on multiple parameters including the geometry of the electrodes, the width, length and height of the microchannel, the size of the particles and the throughput. In this study, COMSOL Multiphysics® modeling along with experimental studies are used to investigate the effect of the aforementioned parameters. The electric field between the electrodes and the induced DEP force on the particles are modelled by COMSOL Multiphysics®. The simulation model is used to show the effect of the DEP force on the particles, and how the geometry of the electrodes (width of the electrodes and the gap between them) plays a role in the manipulation of polystyrene microparticles. The simulation results show that increasing the electrode width to a certain limit, which depends on the height of the channel, increases the induced DEP force. Also, decreasing the gap between the electrodes leads to a stronger DEP force. Based on these results, criteria for the fabrication of the electrodes were found, and soft lithography was used to fabricate interdigitated slanted electrodes and microchannels. Experimental studies were run to find the effect of the flow rate, geometrical parameters of the microchannel such as length, width, and height as well as the electrodes’ angle on the displacement of 5 um, 10 um and 15 um polystyrene particles. An empirical equation is developed to predict the displacement of the particles under different conditions. It is shown that the displacement of the particles is more for longer and lower height channels, lower flow rates, and bigger particles. On the other hand, the effect of the angle of the electrodes on the displacement of the particles was negligible. Based on the results, we have developed an optimum design (in terms of efficiency and throughput) for three size separation of particles.

Keywords: COMSOL Multiphysics, Dielectrophoresis, Microfluidics, Particle separation

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Authors: Suvidha Gupta, R. A. Pandey, Sanjay Pawar

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The effluents from various food processing industries are found with high BOD, COD, suspended solids, nitrate, and phosphate. Mixotrophic growth of microalgae using food processing industrial wastewater as an organic carbon source has emerged as more effective and energy intensive means for the nutrient removal and COD reduction. The present study details the treatment of non-sterilized unfiltered food processing industrial wastewater by microalgae for nutrient removal as well as to determine the tolerance to COD by taking different dilutions of wastewater. In addition, the effect of different inoculum percentages of microalgae on removal efficiency of the nutrients for given dilution has been studied. To see the effect of dilution and COD tolerance, the wastewater having initial COD 5000 mg/L (±5), nitrate 28 mg/L (±10), and phosphate 24 mg/L (±10) was diluted to get COD of 3000 mg/L and 1000 mg/L. The experiments were carried out in 1L conical flask by intermittent aeration with different inoculum percentage i.e. 10%, 20%, and 30% of Chlorella sp. isolated from nearby area of NEERI, Nagpur. The experiments were conducted for 6 days by providing 12:12 light- dark period and determined various parameters such as COD, TOC, NO3-- N, PO4-- P, and total solids on daily basis. Results revealed that, for 10% and 20% inoculum, over 90% COD and TOC reduction was obtained with wastewater containing COD of 3000 mg/L whereas over 80% COD and TOC reduction was obtained with wastewater containing COD of 1000 mg/L. Moreover, microalgae was found to tolerate wastewater containing COD 5000 mg/L and obtained over 60% and 80% reduction in COD and TOC respectively. The obtained results were found similar with 10% and 20% inoculum in all COD dilutions whereas for 30% inoculum over 60% COD and 70% TOC reduction was obtained. In case of nutrient removal, over 70% nitrate removal and 45% phosphate removal was obtained with 20% inoculum in all dilutions. The obtained results indicated that Microalgae assisted nutrient removal gives maximum COD and TOC reduction with 3000 mg/L COD and 20% inoculum. Hence, microalgae assisted wastewater treatment is not only effective for removal of nutrients but also can tolerate high COD up to 5000 mg/L and solid content.

Keywords: Chlorella sp., chemical oxygen demand, food processing industrial wastewater, mixotrophic growth

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Authors: Mariam Kutateladze

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In the twenty-first century, in the customer service settings for hospitality institution’s employee management and their well-being have become a core issue since it is linked to the customers' increased demand for high-quality service. Employees' positive attitude to customers plays an essential role in the serving process; for this reason, in the hospitality institutions service with a smile is a job requirement. This research is devoted to the issues of employee management systems improvement and its effect of the genuine smile as a positive attitude expressed by the employees to the customer. Different researchers work about the effect of the genuine smile, which is analyzed in the present paper. Based on it, the link between satisfied employees from service climate and their genuine smile is determined. An investigation in local resort hotels which are located in the regions of Georgia is conducted. In the methodology of the paper, we have used linkage research, which stated that employee satisfaction in a working place depends on the existing service climate in an organization. We have prepared questioners according to eight dimensions of good service climate by linkage research, and extra questions about the effect of the smile on customers were added. Questionnaires were distributed among employees, and the results have shown that dissatisfaction from organizations’ service climate led to employees' false smile toward customers. Demanding positive emotions from frustrated employees was the mistake of the hotel management. The false smile was easily recognized by the customers, and the frustrated employee with a false smile could not provide high-quality service. The findings of the paper will help managers to realize the importance of forming the positive service climate within the institutions since it is linked to employees' well-being who are the creators of high-quality service. The conclusion drawn from this study indicates there are core issues those managers need to take into account when planning their organizations’ profit. Managers should know their employees very well, their feelings and attitudes toward work before asking them expressing a smile since forced smile does not have a good result and quite often has bad outcomes; therefore, first of all, managers should investigate service climate in the organization. Managers should take into consideration employees’ opinions about the service climate in the organization, motivate their employees, and respect their ideas. Also, they should satisfy employees' basic needs and stress more value on extrinsic goals such as competence, relatedness, and autonomy. Managers should create a positive working environment, positive service climate, which will lead to employee satisfaction and genuine feelings, as well as improve the working environment since negative working climate will cause customers disappointment because of low-quality service provided by the unsatisfied employees.

Keywords: employee management, hotel, quality of service, service climate

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Authors: Imen Harabi, Hanae Toura, Safa Jemai, Bernabe Mari Soucase

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A promising alternative to traditional Quantum Dots QD materials, which contain toxic heavy elements such as lead and cadmium, sheds light on indium phosphide quantum dots (InP QDs) Owing to improve the quantum yields of photoluminescence and other properties. InP, InP/ZnS core/shell and InP/ZnS/ZnS core/shell/shell Quantum Dots (QDs) were synthetized by the hot injection method. The optical and structural properties of the core InP QDs, InP/ZnS QDs, and InP/ZnS/ZnS QDs have being considered by several techniques such as X-ray diffraction, transmission electron microscopy, optical spectroscopy, and photoluminescence. The average diameter of InP, InP/ZnS, and InP/ZnS/ZnS Quantum Dots (QDs) was varying between 10 nm, 5.4 nm, and 4.10 nm. This experience revealed that the surface morphology of the Quantum Dots has a more regular spherical form with color variation of the QDs in solution. The emission peak of colloidal InP Quantum Dots was around 530 nm, while in InP/ZnS, the emission peak is displayed and located at 598 nm. whilst for InP/ZnS/ZnS is placed at 610 nm. Furthermore, an enhanced PL emission due to a passivation effect in the ZnS-covered InP QDs was obtained. Add the XRD information FWHM of the principal peak of InP QDs was 63 nm, while for InP/ZnS was 41 nm and InP/ZnS/ZnS was 33 nm. The effect of the Zinc stearate precursor concentration on the optical, structural, surface chemical of InP and InP/ZnS and InP/ZnS/ZnS QDs will be discussed.

Keywords: indium phosphide, quantum dot, nanoparticle, core-shell, multishell, luminescence

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Authors: Pham Ngoc Thang, Le Thai Hung, Nguyen Quang Bau

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The influence of confined acoustic phonons on the Shubnikov – de Haas magnetoresistance oscillations in a doped semiconductor superlattice (DSSL), subjected in a magnetic field, DC electric field, and a laser radiation, has been theoretically studied based on quantum kinetic equation method. The analytical expression for the magnetoresistance in a DSSL has been obtained as a function of external fields, DSSL parameters, and especially the quantum number m characterizing the effect of confined acoustic phonons. When m goes to zero, the results for bulk phonons in a DSSL could be achieved. Numerical calculations are also achieved for the GaAs:Si/GaAs:Be DSSL and compared with other studies. Results show that the Shubnikov – de Haas magnetoresistance oscillations amplitude decrease as the increasing of phonon confinement effect.

Keywords: Shubnikov–de Haas magnetoresistance oscillations, quantum kinetic equation, confined acoustic phonons, laser radiation, doped semiconductor superlattices

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Authors: C. Panebianco, K. Adamberg, S. Adamberg, C. Saracino, M. Jaagura, K. Kolk, A. Di Chio, P. Graziano, R. Vilu, V. Pazienza

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Background/Aims: Despite recent advances in treatment options, a modest impact on the outcome of the pancreatic cancer (PC) is observed so far. Short-term fasting cycles have the potential to improve the efficacy of chemotherapy against PC. However, diseased people may refuse to follow the fasting regimen and fasting may worsen the weight loss often occurring in cancer patients. Therefore, alternative approaches are needed. The aim of this study was to assess the effect of Engineered Low glycemic food ELGIF mimicking diet on growth of cancer cell lines in vitro and in an in vivo pancreatic cancer mouse xenograft model. Materials and Methods: BxPC-3, MiaPaca-2 and Panc-1 cells were cultured in control and ELGIF mimicking diet culturing condition to evaluate the tumor growth and proliferation pathways. Pancreatic cancer xenograft mice were subjected to ELGIF to assess the tumor volume and weight as compared to mice fed with control diet. Results: Pancreatic cancer cells cultured in ELGIF mimicking medium showed decreased levels of proliferation as compared to those cultured in the standard medium. Consistently, xenograft pancreatic cancer mice subjected to ELGIF diet displayed a significant decrease in tumor growth. Conclusion: A positive effect of ELGIF diet on proliferation in vitro is associated with the decrease of tumor progression in the in vivo PC xenograft mouse model. These results suggest that engineered dietary interventions could be supportive as synergistic approach to enhance the efficacy of existing cancer treatments in pancreatic cancer patients.

Keywords: functional food, microbiota, mouse model, pancreatic cancer

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Authors: Khaled R. Khater

Abstract:

The weight of the SPT hammer is standard (0.623kN). The locally manufacturer drilling rigs use hammers, sometimes deviating off the standard weight. This affects the field measured blow counts (Nf) consequentially, affecting most of correlations previously obtained, as they were obtained based on standard hammer weight. The literature presents energy corrections factor (η2) to be applied to the SPT total input energy. This research investigates the effect of the hammer weight variation, as a single parameter, on the field measured blow counts (Nf). The outcome is a correction factor (ηk), equation, and correction chart. They are recommended to adjust back the measured misleading (Nf) to the standard one as if the standard hammer is used. This correction is very important to be done in such cases where a non-standard hammer is being used because the bore logs in any geotechnical report should contain true and representative values (Nf), let alone the long records of correlations, already in hand. The study here-in is achieved by using laboratory physical model to simulate the SPT dripping hammer mechanism. It is designed to allow different hammer weights to be used. Also, it is manufactured to avoid and eliminate the energy loss sources. This produces a transmitted efficiency up to 100%.

Keywords: correction factors, hammer weight, physical model, standard penetration test

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Authors: Mahadzirah Mohamad, Nur Izzati Ab Ghani

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Worldwide, tourism sustained growth and remained to be one of the fast-growing sectors. Malaysia tourism industry experienced an unstable and declining pattern of international tourist arrival’s growth rate. The situation suggested that the industry was competitive and denoted the need to study factors that influence tourist loyalty. The primary purpose of this study was to develop a model that examined how destination image, perceived value, service quality and tourist satisfaction affect destination loyalty. The study was conducted at the Kuala Lumpur International Airport and Kota Kinabalu International Airport. The respondents were international tourists from United Kingdom and Australia and they were selected using simple random sampling method. A total of 337 respondents were subjected to data analysis using structural equation modelling. The study uncovered that perceived value and destination image was highly correlated and the model suggested that these constructs should be treated as one construct. The construct was labelled as overall destination image. Overall image had significant direct effect on service quality, satisfaction and loyalty. Service quality had a significant indirect effect on loyalty through satisfaction as a moderating variable. However, satisfaction had no mediating effect on the relationship between overall destination image and loyalty. The study suggested that more efforts should be focused on portraying the image of experiencing joy with many interesting natural scenic places to see whilst on a holiday to Malaysia. In addition, the destination management office should promote tourist visiting to Malaysia would enjoy quality service related to accommodation, information facilities, health, and shopping. Tourist satisfaction empirically proved to be an important construct that influenced destination loyalty. This study contributed to the extended knowledge that postulated overall image of a destination was measured by perceived value and destination image.

Keywords: destination image, destination loyalty, structural equation modelling, tourist satisfaction

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Authors: M. K. Kim, C. H. Shin, W. G. Park

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Recently, natural gas resources are issued due to alternative and eco-friendly energy policies, and development of even unconventional gas resources including tight gas, coal bed methane and shale gas is being rapidly expanded from North America all over the world. For developing these gas reservoirs, it is necessary to investigate reservoir characteristics by using reservoir simulation. In reservoir simulation, calculation of permeability of fractured zone is very important to predict the gas production. However, it is difficult to accurately calculate the permeability by using conventional methods which use analytic solution for laminar flow. The flow in gas reservoirs exhibits complex flow behavior such as slip around the wall roughness effect and turbulence because the size of the apertures of fractures is ranged over various scales from nano-scale to centi-scale. Therefore, it is required to apply new reservoir flow analysis methods which can accurately consider complex gas flow owing to the geometric characteristics and distributions of various pores and flow paths within gas reservoirs. Hence, in this study, the flow characteristics and the relation between each characteristic variable was investigated and multi-effect was quantified when the fractures are compounded for devising a new calculation model of permeability of fractured zone in gas reservoirs by using CFD.

Keywords: fractured zone, gas reservoir, permeability, CFD

Procedia PDF Downloads 249

Authors: Vipin Kumar Verma, Neeta Sehgal, Om Prakash

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Cyprinus carpio has a wide spread occurrence in the lakes and rivers of Europe and Asia. Heavy losses in natural environment due to anthropogenic activities, including pollution as well as pathogenic diseases have landed this fish in IUCN red list of vulnerable species. The significance of a suitable diet in preserving the health status of fish is widely recognized. In present study, artificial feed supplemented with leaves of two weed plants, Eichhornia crassipes and Ricinus communis were evaluated for their role on the fish immune system. To achieve this objective fish were acclimatized to laboratory conditions (25 ± 1 °C; 12 L: 12D) for 10 days prior to start of experiment and divided into 4 groups: non-challenged (negative control= A), challenged [positive control (B) and experimental (C & D)]. Group A, B were fed with non-supplemented feed while group C & D were fed with feed supplemented with 5% Eichhornia crassipes and 5% Ricinus communis respectively. Supplemented feeds were evaluated for their effect on growth, health, immune system and disease resistance in fish when challenged with Vibrio harveyi. Fingerlings of C. carpio (weight, 2.0±0.5 g) were exposed with fresh overnight culture of V. harveyi through bath immunization (concentration 2 Χ 105) for 2 hours on 10 days interval for 40 days. The growth was monitored through increase in their relative weight. The rate of mortality due to bacterial infection as well as due to effect of feed was recorded accordingly. Immune response of fish was analyzed through differential leucocyte count, percentage phagocytosis and phagocytic index. The effect of V. harveyi on fish organs were examined through histo-pathological examination of internal organs like spleen, liver and kidney. The change in the immune response was also observed through gene expression analysis. The antioxidant potential of plant extracts was measured through DPPH and FRAP assay and amount of total phenols and flavonoids were calculates through biochemical analysis. The chemical composition of plant’s methanol extracts was determined by GC-MS analysis, which showed presence of various secondary metabolites and other compounds. Investigation revealed immuno-modulatory effect of plants, when supplemented with the artificial feed of fish.

Keywords: immuno-modulation, gc-ms, Cyprinus carpio, Eichhornia crassipes, Ricinus communis

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Authors: Shelly Sharma, Pooja Chadha

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Humans are exposed to pesticides and insecticides either directly or indirectly. Exposure to these pesticides may lead to acute toxicity to mammals and non-target organisms. Chlorpyrifos (CPF) is a broad spectrum organophosphate pesticide widely used in various countries of the world. The aim of the present study was to assess the toxicity associated with chlorpyrifos exposure and possible mitigating effect of cow urine against genotoxic and toxic effects in rat brain induced by chlorpyrifos. For this purpose LD50 was determined and rats were orally administered with 1/8th of LD50 (19mg/kg b.wt). Brain samples were taken after 24hrs, 48hrs and 72hrs of treatment. A significant increase in the % tail DNA was observed along with the increase in MDA levels of brain tissues in chlorpyrifos treated groups as compared to control. Cow urine treated groups show decrease in DNA damage and MDA levels as compared to CPF treated group. The study indicates that cow urine has ameliorative potential against neurotoxicity and genotoxicity induced by CPF. Cow urine is considered rich in vitamin A, E and volatile fatty acids which provide antioxidant potential to it. Thus, it can be used as a genoprotective agent.

Keywords: comet assay, brain, cow urine, genotoxicity, toxicity

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Authors: Paula Buldres, Jorge Toledo

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Objectives: This study aimed to characterize potential probiotic strains isolated from canine breast milk for use in dogs with enteropathies. Methodology: Six canine breast milk strains, one canine colostrum strain, and one control porcine breast milk strain were characterized. According to its functional properties of resistance to acids, different concentrations of bile salts, and pancreatin, its presumptive properties of safety and inhibitory effect on pathogens, non-cytotoxic characteristics, and adhesion to the intestine. The immunomodulatory effect of formulations with better probiotic characterization in vitro and in vivo was also analyzed. Results: Two strains characterized as potential probiotics were obtained, which corresponded to the canine strains (TUCO-16 and TUCO-17), presenting resistance to acidic pH, bile salts, and pancreatin, as well as an inhibitory effect on pathogenic Escherichia coli, Salmonella sp., and Clostridium perfringens. Strains TUCO-16 and TUCO-17 induced a significant increase in the expression of TNF-α and IL-8 in canine macrophages, respectively. Expression analyses of pattern recognition receptors in DH82 cells suggest that TUCO-16 and TUCO-17 might increase the TLR2 expression marker, and porcine strain (TUCO-4) increases the NOD2 expression marker. Based on the count obtained and the encapsulation yield, the best formulations correspond to FOS-Inulin for the TUCO-17 and TUCO-4 strains; Maltodextrin-Inulin for TUCO-16. All the strains are non-cytotoxic. The strain that showed the highest adhesion to intestinal epithelial cells was TUCO-17 with the FOS-Inulin formulation. On the other hand, the probiotics decreased the expression of pro-inflammatory markers in vivo, both in the intestine and in the spleen of mice. Conclusion: The combination of these three strains under study (TUCO-16, TUCO-17, and TUCO-4) would cover the probiotic properties in formulation and immunomodulation of all the markers under study.

Keywords: probiotics, gastrointestinal infec, dog, probiotic formulation, immunomodulatory probiotics

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Authors: Samira Bensoltane, Smina Ait Hamlet, Samti Meriem, Semmasel Asma

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Living organisms in the soil are subject to regular fluctuations of abiotic parameters, as well as a chemical contamination of the environment due to human activities. They are subject to multiple stressors they face. The aim of our work was to study the effects of insecticide: thiamethoxam (neonicotinoid), and the potential reversibility of the effects by an antioxidant: ginger on a bioindicator species in ecotoxicology, the land snail Helix aspersa. The effects were studied by a targeted cell approach of evaluating the effect of these molecules on tissue and cellular aspect of hepatopancreas through histological study. Treatment with thiamethoxam concentrations 10, 20, and 40 mg/l shows signs of inflammation even at low concentrations and from the 5th day of treatment. Histological examination of the hepatopancreas of snails treated with thiamethoxam showed significant changes from the lowest concentrations tested , note intertubular connective tissue enlargement, necrosis deferent types of cells (cells with calcium , digestive, excretory) , also damage acini, alteration of the apical membrane and lysis of the basement membrane in a dose- dependent manner. After 10 days of treatment and with 40 mg/l, the same changes were observed with a very advanced degeneration of the wall of the member that could be confused with the cell debris. For cons, the histological study of the hepatopancreas in Helix aspersa treated with ginger for a period of 15 days after stopping treatment with thiamethoxam has shown a partial regeneration of hepatopancreatic tissue snails treated with all concentrations of thiamethoxam and especially in the intertubular connective tissue of the wall and hepatopancreatic digestive tubules. Finally, we can conclude that monitoring the effect of the insecticide thiamethoxam showed significant alterations, however, treatment with ginger shows regeneration of damaged cells themselves much sharper at low concentration (10 mg/L).

Keywords: Helix aspersa, insecticides, thiamethoxam, ginger, hepatopancreas

Procedia PDF Downloads 215

Authors: Saeedeh Eshkil, Seyedeh Farnaz Mousavi, Hamid Reza Kianifar, Seyed Java Sayyedi, Mehdi Sohrabi, Elham Bakhtiari, Morteza Mashoughi, Ezzat Khodashenas

Abstract:

Background: The effect of the SPARK physical education program on lung function in cystic fibrosis patients is not yet determined.).SPARK is Sports, play and active recreation for kids, including moving skills, aerobic games, jogging or walking, aerobic dance and jump rope. Regarding the high prevalence of cystic fibrosis and its destructive effects on the lungs, the aim of this study is to evaluate lung function and quality of life before and after undergoing the SPARK physical education program in children with cystic fibrosis. Method: In this quasi-experimental study, all patients with cystic fibrosis aged 6-18 years referred to the cystic fibrosis clinic of Dr. Sheikh Hospital were enrolled. The patients went under 12 weeks of SPARK training program (3 sessions per week, each session 45 minutes). The quality of life questionnaire ( Cystic Fibrosis Questionnaire includes self-examination, parental ) for patients with cystic fibrosis and spirometry indices (FEV1, FVC, FEV1/FVC, FEF25-75) was filled out before and after intervention for all patients. Results The mean and standard deviation of patients' age were 9.85±2.67 years, and 65% of patients were female. The FEV1 was significantly different before and after the SPARK physical education program (P=0.03), and the respiratory component of quality of life significantly increased after intervention (P=0.002). The overall score of quality of life from parents’ point of view was 2.87 ± 0.38, which increased to 2.99 ± 0.38 after the intervention. Conclusion: The SPARK training program may improve the spirometric parameters in children with cystic fibrosis. It also had a significant effect on improving the quality of life of patients, especially in the respiratory component.

Keywords: cystic fibrosis, pediatrics, SPARK motor program, spirometry

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