We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confin...We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.展开更多
The idea of linear Diophantine fuzzy set(LDFS)theory with its control parameters is a strong model for machine learning and optimization under uncertainty.The activity times in the critical path method(CPM)representat...The idea of linear Diophantine fuzzy set(LDFS)theory with its control parameters is a strong model for machine learning and optimization under uncertainty.The activity times in the critical path method(CPM)representation procedures approach are initially static,but in the Project Evaluation and Review Technique(PERT)approach,they are probabilistic.This study proposes a novel way of project review and assessment methodology for a project network in a linear Diophantine fuzzy(LDF)environment.The LDF expected task time,LDF variance,LDF critical path,and LDF total expected time for determining the project network are all computed using LDF numbers as the time of each activity in the project network.The primary premise of the LDF-PERT approach is to address ambiguities in project network activity timesmore simply than other approaches such as conventional PERT,Fuzzy PERT,and so on.The LDF-PERT is an efficient approach to analyzing symmetries in fuzzy control systems to seek an optimal decision.We also present a new approach for locating LDF-CPM in a project network with uncertain and erroneous activity timings.When the available resources and activity times are imprecise and unpredictable,this strategy can help decision-makers make better judgments in a project.A comparison analysis of the proposed technique with the existing techniques has also been discussed.The suggested techniques are demonstrated with two suitable numerical examples.展开更多
Dear Editor,We read with great interest the recent case report and review by Khalife et al on the occurrence of ovarian hyperstimulation syndrome(OHSS)following GnRH agonist triggering and a freeze-all strategy in a p...Dear Editor,We read with great interest the recent case report and review by Khalife et al on the occurrence of ovarian hyperstimulation syndrome(OHSS)following GnRH agonist triggering and a freeze-all strategy in a patient undergoing assisted reproductive technology(ART)[1].This report provides valuable insights into the management of OHSS,particularly in the context of polycystic ovary syndrome(PCOS),a prevalent condition in reproductive medicine.We would like to relate these findings to our previously published work on the impact of PCOS on embryo quality and intracytoplasmic sperm injection(ICSI)outcomes in Iraqi women[2],highlighting the common significance of the topic and future clinical approaches.展开更多
This study aims to improve knowledge of the structure of southwest Cameroon based on the analysis and interpretation of gravity data derived from the SGG-UGM-2 model. A residual anomaly map was first calculated from t...This study aims to improve knowledge of the structure of southwest Cameroon based on the analysis and interpretation of gravity data derived from the SGG-UGM-2 model. A residual anomaly map was first calculated from the Bouguer anomaly map, which is strongly affected by a regional gradient. The residual anomaly map generated provides information on the variation in subsurface density, but does not provide sufficient information, hence the interest in using filtering with the aim of highlighting the structures affecting the area of south-west Cameroon. Three interpretation methods were used: vertical gradient, horizontal gradient coupled with upward continuation and Euler deconvolution. The application of these treatments enabled us to map a large number of gravimetric lineaments materializing density discontinuities. These lineaments are organized along main preferential directions: NW-SE, NNE-SSW, ENE-WSW and secondary directions: NNW-SSE, NE-SW, NS and E-W. Euler solutions indicate depths of up to 7337 m. Thanks to the results of this research, significant information has been acquired, contributing to a deeper understanding of the structural composition of the study area. The resulting structural map vividly illustrates the major tectonic events that shaped the geological framework of the study area. It also serves as a guide for prospecting subsurface resources (water and hydrocarbons). .展开更多
The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As a...The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As an application, the existence of positive periodic solution for a logarithmic population model is established under some conditions.展开更多
This paper deals with the dyeing of cotton fabrics with microwave irradiation.The compara-tive experiments of the microwave dyeing to the conventional dyeing were carried out and themechanism was also discussed.Being ...This paper deals with the dyeing of cotton fabrics with microwave irradiation.The compara-tive experiments of the microwave dyeing to the conventional dyeing were carried out and themechanism was also discussed.Being subjected to microwave irradiation,the penetration of dyesand chemicals into the fabric can be achieved in a short time with a good color yield.The irradiatedmaterials generate heat via dielectric heating by high frequency electro-magnetic field and as a re-sult,energy saving can be realized.Based on the examination and analysis with X-ray diffraction,IR,SEM,and XPS,the reduction in crystallinity,the formation of active carbonyl groups of freeradicals containing oxygen and the morphological changes in the irradiated cottom fibers werefound.All of these may be believed in favour of the dyeing process.展开更多
The replication of HIV-1 requires the integration of its cyclic DNA into host DNA by HIV-1 integrase (IN), which includes two important reactions, 3'-processing and strand transfer, both catalyzed by HIV-1 IN. Disr...The replication of HIV-1 requires the integration of its cyclic DNA into host DNA by HIV-1 integrase (IN), which includes two important reactions, 3'-processing and strand transfer, both catalyzed by HIV-1 IN. Disrupting either of the reactions will fulfill the purpose of inhibiting the replication of HIV-1. In this paper, pharmacophore modeling and molecular docking are employed to investigate the inhibition mechanism of the HIV-1 IN strand transfer inhibitors (INSTIs). Based on the results, we suggest that the inhibition mechanism of INSTIs involves the inhibitor chelating the cofactors Mg2+ and its forming hydrogen bonds with some crucial residues adjacent to the DDE active center.展开更多
In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator.This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an ex...In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator.This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force.We applied the multiple scales method to get the solution from first approximation.Graphically and numerically,we studied the system before and after adding time delay feedback at the primary resonance case(ffi!).We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system.展开更多
Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography...Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography(DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of "to-and-fro" waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of "toand-fro" waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and "to-and-fro" flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional "toand-fro" waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the "to-andfro" waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.展开更多
A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electroc...A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.展开更多
In this paper,a discrete Lotka-Volterra predator-prey model is proposed that considers mixed functional responses of Holling types I and III.The equilibrium points of the model are obtained,and their stability is test...In this paper,a discrete Lotka-Volterra predator-prey model is proposed that considers mixed functional responses of Holling types I and III.The equilibrium points of the model are obtained,and their stability is tested.The dynamical behavior of this model is studied according to the change of the control parameters.We find that the complex dynamical behavior extends from a stable state to chaotic attractors.Finally,the analytical results are clarified by some numerical simulations.展开更多
Objective:To extract,quantify,and evaluate the phenolic content in Opuntia ficus-indica skin for their antioxidant capacity with three different methods(ABTS,DPPH,and lipid oxidation)and to optimize the extraction con...Objective:To extract,quantify,and evaluate the phenolic content in Opuntia ficus-indica skin for their antioxidant capacity with three different methods(ABTS,DPPH,and lipid oxidation)and to optimize the extraction conditions[time,temperature and ethanol concentration)in a reflux system.Methods:The extraction process was done using a reflux system.A San CristobalⅡexperimental design with three variables and three levels was used.The variables evaluated were time of extraction(h),concentration of ethanol(%,v/v)and temperature(°C).The extraction process was optimized using a response surface methodology.Results:It was observed that at higher temperature more phenolic compounds were extracted,but the antioxidant capacity was decreased.The optimum conditions for phenolic compounds extraction and antioxidant capacity mixing the three methods were as Follows:45%of ethanol,80℃and 2 hours of extraction.Values obtained in our results are little higher that other previously reported.Conclusions:It can he concluded the by-products of Opuntia ficus-indica represent a good source of natural antioxidants with possible applications in food,cosmetics or drugs industries.展开更多
Peristaltic motion induced by a surface acoustic wave of a viscous, compressible and electrically conducting Maxwell fluid in a confined parallel-plane microchannel through a porous medium is investigated in the prese...Peristaltic motion induced by a surface acoustic wave of a viscous, compressible and electrically conducting Maxwell fluid in a confined parallel-plane microchannel through a porous medium is investigated in the presence of a constant magnetic field. The slip velocity is considered and the problem is discussed only for the free pumping case. A perturbation technique is employed to analyze the problem in terms of a small amplitude ratio. The phenomenon of a “backward flow” is found to exist in the center and at the boundaries of the channel. In the second order approximation, the net axial velocity is calculated for various values of the fluid parameters. Finally, the effects of the parameters of interest on the mean axial velocity, the reversal flow, and the perturbation function are discussed and shown graphically. We find that in the non-Newtonian regime, there is a possibility of a fluid flow in the direction opposite to the propagation of the traveling wave. This work is the most general model of peristalsis created to date with wide-ranging applications in biological, geophysical and industrial fluid dynamics.展开更多
The peristaltic flow of a non-Newtonian nanofluid with swimming oxytactic microorganisms through a space between two infinite coaxial conduits is investigated. A variable magnetic field is applied on the flow. The bio...The peristaltic flow of a non-Newtonian nanofluid with swimming oxytactic microorganisms through a space between two infinite coaxial conduits is investigated. A variable magnetic field is applied on the flow. The bioconvection flow and heat transfer in the porous annulus are formulated, and appropriate transformations are used, leading to the non-dimensionalized ruling partial differential equation model. The model is then solved by using the homotopy perturbation scheme. The effects of the germane parameters on the velocity profile, temperature distribution, concentration distribution, motile microorganism profile, oxytactic profile, pressure rise, and outer and inner tube friction forces for the blood clot and endoscopic effects are analyzed and presented graphically.It is noticed that the pressure rise and friction forces attain smaller values for the endoscopic model than for the blood clot model. The present analysis is believed to aid applications constituting hemodynamic structures playing indispensable roles inside the human body since some blood clotting disorders, e.g., haemophilia, occur when some blood constituents on the artery wall get confined away from the wall joining the circulation system.展开更多
This paper deals with the problem of the postbuckling response of a thin cantilever beam ofnon-linear material, subjected to subtangential follower forces. Based on the well-knownBernoulli-Euler bending moment-curvatu...This paper deals with the problem of the postbuckling response of a thin cantilever beam ofnon-linear material, subjected to subtangential follower forces. Based on the well-knownBernoulli-Euler bending moment-curvature relation, the proposed problem is reduced to a specialeigenvalue problem of non-linear differential equation. An approximate solution is achieved byusing a simple and very effective technique, which leads to reliable results even in the case of verylarge deflections. The initial postbuckling path depending on the subtangential follower forces inequilibrium is then obtained. Moreover, the individual and coupling effect of the subtangential fol-lower force, the material non-linearity and the beam slenderness ratio on the initial postbucklingpath are also discussed in detail.展开更多
Parasitic angiosperm Alectra vogelii Benth is a growing problem in Malawi, particularly with current emphasis on legumes. Therefore, two studies were set in order to understand the possible mechanisms of resistance in...Parasitic angiosperm Alectra vogelii Benth is a growing problem in Malawi, particularly with current emphasis on legumes. Therefore, two studies were set in order to understand the possible mechanisms of resistance in cowpea genotypes on their reaction to the parasitic weed. In the first experiment, Mkanakaufiti, IT99K-7-21-2-2XIT82E-16, Sudan 1 and IT82E-16 were grown in Alectra infested and non-infested pots. The experiment (2*4 factorial treatment combination) was arranged in an RCBD and replicated eight times. The second experiment, involved Petri-dish techniques where 4 genotype roots were assessed on their ability to stimulate the germination of A. vogelii as a proxy for germination stimulant production. The experiment was arranged in an RCBD and replicated five times. In the first experiment, data was collected on;the number of days to first Alectra emergence, Alectra shoot counts at 6, 8, 10, and 12 weeks after planting (WAP), Alectra attachment at 5 and 12 WAP, Alectra biomass at 12 WAP, cowpea biomass parameters at 5 and 12 WAP, yield and yield components per pot. While in the second experiment, number of germinated Alectra seeds per Petri dishes was recorded. The results indicated that IT82E-16 (33.25 days) and Sudan 1 (34.25 days) were earlier infested whilst late on IT99K-7-21-2-2XIT82E-16 (38 days) which correlated to the number of Alectra attachments. There were significant differences (p = 0.05) in weekly Alectra counts between cowpea varieties from 6 up to 10 WAP. Mkanakaufiti and IT99K-7-21-2-2XIT82E-16 were observed with no and few Alectra shoots infestation respectively which was an indicator of resistance mechanism in the study. Number of pods, grain weight (g) and harvest index per pot were significantly affected by inoculation protocol with lower yield on infested cowpea genotypes. The same trend was observed on cowpea varieties where Mkanakaufiti (21.9 g/pot) shown higher yield followed by IT82E-16 (12.5 g/pot) which is susceptible but with tolerance ability to the parasitic weed. The study has shown that resistance mechanisms can be categorized as no or few Alectra shoots, death of Alectra shoots and late infestation. In the Petri dishes, only 3 WAP grown Mkanakaufiti root media failed to induce the germination of Alectra seeds while the opposite occurred on IT82E-16, Sudan 1 and IT99K-7-21-2-2XIT82E-16. On the contrary, 4 WAP grown root media of the four genotypes stimulated Alectra germination which shed more light on the seed behaviour in the soil. This is worth exploring as more could be known to what causes termination of Alectra shoots on Mkanakaufiti. Still, intensifying resistant genotypes should be a goal in order to reduce Alectra seed banks in the soil, thereby, increasing cowpea yield.展开更多
The effects of TiO2 on sintering and nonlinear electrical properties of(98.5-x)ZnO–0.5MnO2–0.5Co2O3-0.5Bi2O3–xTiO2(x = 0.3,0.5,0.7,0.9 mol%) ceramic varistors prepared by the ceramic technique are investigated ...The effects of TiO2 on sintering and nonlinear electrical properties of(98.5-x)ZnO–0.5MnO2–0.5Co2O3-0.5Bi2O3–xTiO2(x = 0.3,0.5,0.7,0.9 mol%) ceramic varistors prepared by the ceramic technique are investigated in this work.The optimum sintering temperature of the prepared samples is deduced by determining the firing shrinkage and water absorption percentages.The optimum sintering temperature is found to be 1200℃,at which each of the samples shows a maximum firing shrinkage and minimum water absorption.Also minimum water absorption appears in a sample of x = 0.9 mol%.Higher sintering temperature and longer sintering time give rise to a reduction in bulk density due to the increased amount of porosity between the large grains of ZnO resulting from the rapid grain growth induced by the liquid phase sintering.The crystal size of ZnO decreases with increasing TiO2 doping.The addition of TiO2 improves the nonlinear coefficient and attains its maximum value at x = 0.7 mol% of TiO2,further addition negatively affects it.A decrease in capacitance consequently in the dielectric constant is recorded with increasing the frequency in a range of 30 kHz–200 kHz.The temperature and composition dependences of the dielectric constant and AC conductivity are also studied.The increase of temperature raises the dielectric constant because it increases ionic response to the field at any particular frequency.展开更多
Heat transfer in an Eyring-Powell fluid that conducts electricity and flows past an exponentially growing sheet is considered.As the sheet is stretched in the x direction,the flow develops in the region with y>0.Th...Heat transfer in an Eyring-Powell fluid that conducts electricity and flows past an exponentially growing sheet is considered.As the sheet is stretched in the x direction,the flow develops in the region with y>0.The problem is tackled through a set of partial differential equations accounting for Magnetohydrodynamics(MHD),radiation and Joule heating effects,which are converted into a set of equivalent ordinary differential equations through a similarity transformation.The converted problem is solved in MATLAB in the framework a fourth order accurate integration scheme.It is found that the thermal relaxation period is inversely proportional to the thickness of the thermal boundary layer,whereas the Eckert-number displays the opposite trend.As this characteristic number grows,the temperature within the channel increases.展开更多
基金financially supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.12174143 and U2032215)the Natural Science Foundation Project of Liaoning Province(Grant No.2022-MS-377)。
文摘We propose a feasible strategy of intercepting the layered polymeric nitrogen(LP-N)and hexagonal layered polymeric nitrogen(HLP-N)at ambient conditions by using the confinement templates.The stable mechanism of confined LP-N and HLP-N at ambient conditions is revealed.
基金supported by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia[Grant No.GRANT3862].
文摘The idea of linear Diophantine fuzzy set(LDFS)theory with its control parameters is a strong model for machine learning and optimization under uncertainty.The activity times in the critical path method(CPM)representation procedures approach are initially static,but in the Project Evaluation and Review Technique(PERT)approach,they are probabilistic.This study proposes a novel way of project review and assessment methodology for a project network in a linear Diophantine fuzzy(LDF)environment.The LDF expected task time,LDF variance,LDF critical path,and LDF total expected time for determining the project network are all computed using LDF numbers as the time of each activity in the project network.The primary premise of the LDF-PERT approach is to address ambiguities in project network activity timesmore simply than other approaches such as conventional PERT,Fuzzy PERT,and so on.The LDF-PERT is an efficient approach to analyzing symmetries in fuzzy control systems to seek an optimal decision.We also present a new approach for locating LDF-CPM in a project network with uncertain and erroneous activity timings.When the available resources and activity times are imprecise and unpredictable,this strategy can help decision-makers make better judgments in a project.A comparison analysis of the proposed technique with the existing techniques has also been discussed.The suggested techniques are demonstrated with two suitable numerical examples.
文摘Dear Editor,We read with great interest the recent case report and review by Khalife et al on the occurrence of ovarian hyperstimulation syndrome(OHSS)following GnRH agonist triggering and a freeze-all strategy in a patient undergoing assisted reproductive technology(ART)[1].This report provides valuable insights into the management of OHSS,particularly in the context of polycystic ovary syndrome(PCOS),a prevalent condition in reproductive medicine.We would like to relate these findings to our previously published work on the impact of PCOS on embryo quality and intracytoplasmic sperm injection(ICSI)outcomes in Iraqi women[2],highlighting the common significance of the topic and future clinical approaches.
文摘This study aims to improve knowledge of the structure of southwest Cameroon based on the analysis and interpretation of gravity data derived from the SGG-UGM-2 model. A residual anomaly map was first calculated from the Bouguer anomaly map, which is strongly affected by a regional gradient. The residual anomaly map generated provides information on the variation in subsurface density, but does not provide sufficient information, hence the interest in using filtering with the aim of highlighting the structures affecting the area of south-west Cameroon. Three interpretation methods were used: vertical gradient, horizontal gradient coupled with upward continuation and Euler deconvolution. The application of these treatments enabled us to map a large number of gravimetric lineaments materializing density discontinuities. These lineaments are organized along main preferential directions: NW-SE, NNE-SSW, ENE-WSW and secondary directions: NNW-SSE, NE-SW, NS and E-W. Euler solutions indicate depths of up to 7337 m. Thanks to the results of this research, significant information has been acquired, contributing to a deeper understanding of the structural composition of the study area. The resulting structural map vividly illustrates the major tectonic events that shaped the geological framework of the study area. It also serves as a guide for prospecting subsurface resources (water and hydrocarbons). .
文摘The existence of T_periodic solutions of the nonlinear system with multiple delays is studied. By using the topological degree method, sufficient conditions are obtained for the existence of T_periodic solutions. As an application, the existence of positive periodic solution for a logarithmic population model is established under some conditions.
文摘This paper deals with the dyeing of cotton fabrics with microwave irradiation.The compara-tive experiments of the microwave dyeing to the conventional dyeing were carried out and themechanism was also discussed.Being subjected to microwave irradiation,the penetration of dyesand chemicals into the fabric can be achieved in a short time with a good color yield.The irradiatedmaterials generate heat via dielectric heating by high frequency electro-magnetic field and as a re-sult,energy saving can be realized.Based on the examination and analysis with X-ray diffraction,IR,SEM,and XPS,the reduction in crystallinity,the formation of active carbonyl groups of freeradicals containing oxygen and the morphological changes in the irradiated cottom fibers werefound.All of these may be believed in favour of the dyeing process.
基金supported by the National Natural Science Foundation of China (No. 30472166)the Tianjin Commission of Science and Technology (06YFGZSH07000)
文摘The replication of HIV-1 requires the integration of its cyclic DNA into host DNA by HIV-1 integrase (IN), which includes two important reactions, 3'-processing and strand transfer, both catalyzed by HIV-1 IN. Disrupting either of the reactions will fulfill the purpose of inhibiting the replication of HIV-1. In this paper, pharmacophore modeling and molecular docking are employed to investigate the inhibition mechanism of the HIV-1 IN strand transfer inhibitors (INSTIs). Based on the results, we suggest that the inhibition mechanism of INSTIs involves the inhibitor chelating the cofactors Mg2+ and its forming hydrogen bonds with some crucial residues adjacent to the DDE active center.
文摘In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator.This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force.We applied the multiple scales method to get the solution from first approximation.Graphically and numerically,we studied the system before and after adding time delay feedback at the primary resonance case(ffi!).We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system.
基金Supported by College of Applied Medical Sciences Research Center and the Deanship of Scientific Research at King Saud University,Riyadh,Saudi Arabia
文摘Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography(DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of "to-and-fro" waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of "toand-fro" waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and "to-and-fro" flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional "toand-fro" waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the "to-andfro" waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.
基金National Natural Science Foundation of China(No. 20071014)
文摘A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, ^1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.
基金the Deanship of Scientific Research at King Khalid University for funding this work through the Big Research Group Project under grant number(R.G.P2/16/40).
文摘In this paper,a discrete Lotka-Volterra predator-prey model is proposed that considers mixed functional responses of Holling types I and III.The equilibrium points of the model are obtained,and their stability is tested.The dynamical behavior of this model is studied according to the change of the control parameters.We find that the complex dynamical behavior extends from a stable state to chaotic attractors.Finally,the analytical results are clarified by some numerical simulations.
基金Supported by the Universidad Autonoma de Coahuila and the Consejo Nacional de Ciencia y Tecnologia(CONACYT).Grant number:COAH-2010C13-147563
文摘Objective:To extract,quantify,and evaluate the phenolic content in Opuntia ficus-indica skin for their antioxidant capacity with three different methods(ABTS,DPPH,and lipid oxidation)and to optimize the extraction conditions[time,temperature and ethanol concentration)in a reflux system.Methods:The extraction process was done using a reflux system.A San CristobalⅡexperimental design with three variables and three levels was used.The variables evaluated were time of extraction(h),concentration of ethanol(%,v/v)and temperature(°C).The extraction process was optimized using a response surface methodology.Results:It was observed that at higher temperature more phenolic compounds were extracted,but the antioxidant capacity was decreased.The optimum conditions for phenolic compounds extraction and antioxidant capacity mixing the three methods were as Follows:45%of ethanol,80℃and 2 hours of extraction.Values obtained in our results are little higher that other previously reported.Conclusions:It can he concluded the by-products of Opuntia ficus-indica represent a good source of natural antioxidants with possible applications in food,cosmetics or drugs industries.
文摘Peristaltic motion induced by a surface acoustic wave of a viscous, compressible and electrically conducting Maxwell fluid in a confined parallel-plane microchannel through a porous medium is investigated in the presence of a constant magnetic field. The slip velocity is considered and the problem is discussed only for the free pumping case. A perturbation technique is employed to analyze the problem in terms of a small amplitude ratio. The phenomenon of a “backward flow” is found to exist in the center and at the boundaries of the channel. In the second order approximation, the net axial velocity is calculated for various values of the fluid parameters. Finally, the effects of the parameters of interest on the mean axial velocity, the reversal flow, and the perturbation function are discussed and shown graphically. We find that in the non-Newtonian regime, there is a possibility of a fluid flow in the direction opposite to the propagation of the traveling wave. This work is the most general model of peristalsis created to date with wide-ranging applications in biological, geophysical and industrial fluid dynamics.
基金TWAS-Italy for the financial support of her visit to UNAM under the TWAS-UNESCO Associateshipthe FORDECYTCONACYT for the financial support under the aforementioned agreement。
文摘The peristaltic flow of a non-Newtonian nanofluid with swimming oxytactic microorganisms through a space between two infinite coaxial conduits is investigated. A variable magnetic field is applied on the flow. The bioconvection flow and heat transfer in the porous annulus are formulated, and appropriate transformations are used, leading to the non-dimensionalized ruling partial differential equation model. The model is then solved by using the homotopy perturbation scheme. The effects of the germane parameters on the velocity profile, temperature distribution, concentration distribution, motile microorganism profile, oxytactic profile, pressure rise, and outer and inner tube friction forces for the blood clot and endoscopic effects are analyzed and presented graphically.It is noticed that the pressure rise and friction forces attain smaller values for the endoscopic model than for the blood clot model. The present analysis is believed to aid applications constituting hemodynamic structures playing indispensable roles inside the human body since some blood clotting disorders, e.g., haemophilia, occur when some blood constituents on the artery wall get confined away from the wall joining the circulation system.
文摘This paper deals with the problem of the postbuckling response of a thin cantilever beam ofnon-linear material, subjected to subtangential follower forces. Based on the well-knownBernoulli-Euler bending moment-curvature relation, the proposed problem is reduced to a specialeigenvalue problem of non-linear differential equation. An approximate solution is achieved byusing a simple and very effective technique, which leads to reliable results even in the case of verylarge deflections. The initial postbuckling path depending on the subtangential follower forces inequilibrium is then obtained. Moreover, the individual and coupling effect of the subtangential fol-lower force, the material non-linearity and the beam slenderness ratio on the initial postbucklingpath are also discussed in detail.
文摘Parasitic angiosperm Alectra vogelii Benth is a growing problem in Malawi, particularly with current emphasis on legumes. Therefore, two studies were set in order to understand the possible mechanisms of resistance in cowpea genotypes on their reaction to the parasitic weed. In the first experiment, Mkanakaufiti, IT99K-7-21-2-2XIT82E-16, Sudan 1 and IT82E-16 were grown in Alectra infested and non-infested pots. The experiment (2*4 factorial treatment combination) was arranged in an RCBD and replicated eight times. The second experiment, involved Petri-dish techniques where 4 genotype roots were assessed on their ability to stimulate the germination of A. vogelii as a proxy for germination stimulant production. The experiment was arranged in an RCBD and replicated five times. In the first experiment, data was collected on;the number of days to first Alectra emergence, Alectra shoot counts at 6, 8, 10, and 12 weeks after planting (WAP), Alectra attachment at 5 and 12 WAP, Alectra biomass at 12 WAP, cowpea biomass parameters at 5 and 12 WAP, yield and yield components per pot. While in the second experiment, number of germinated Alectra seeds per Petri dishes was recorded. The results indicated that IT82E-16 (33.25 days) and Sudan 1 (34.25 days) were earlier infested whilst late on IT99K-7-21-2-2XIT82E-16 (38 days) which correlated to the number of Alectra attachments. There were significant differences (p = 0.05) in weekly Alectra counts between cowpea varieties from 6 up to 10 WAP. Mkanakaufiti and IT99K-7-21-2-2XIT82E-16 were observed with no and few Alectra shoots infestation respectively which was an indicator of resistance mechanism in the study. Number of pods, grain weight (g) and harvest index per pot were significantly affected by inoculation protocol with lower yield on infested cowpea genotypes. The same trend was observed on cowpea varieties where Mkanakaufiti (21.9 g/pot) shown higher yield followed by IT82E-16 (12.5 g/pot) which is susceptible but with tolerance ability to the parasitic weed. The study has shown that resistance mechanisms can be categorized as no or few Alectra shoots, death of Alectra shoots and late infestation. In the Petri dishes, only 3 WAP grown Mkanakaufiti root media failed to induce the germination of Alectra seeds while the opposite occurred on IT82E-16, Sudan 1 and IT99K-7-21-2-2XIT82E-16. On the contrary, 4 WAP grown root media of the four genotypes stimulated Alectra germination which shed more light on the seed behaviour in the soil. This is worth exploring as more could be known to what causes termination of Alectra shoots on Mkanakaufiti. Still, intensifying resistant genotypes should be a goal in order to reduce Alectra seed banks in the soil, thereby, increasing cowpea yield.
文摘The effects of TiO2 on sintering and nonlinear electrical properties of(98.5-x)ZnO–0.5MnO2–0.5Co2O3-0.5Bi2O3–xTiO2(x = 0.3,0.5,0.7,0.9 mol%) ceramic varistors prepared by the ceramic technique are investigated in this work.The optimum sintering temperature of the prepared samples is deduced by determining the firing shrinkage and water absorption percentages.The optimum sintering temperature is found to be 1200℃,at which each of the samples shows a maximum firing shrinkage and minimum water absorption.Also minimum water absorption appears in a sample of x = 0.9 mol%.Higher sintering temperature and longer sintering time give rise to a reduction in bulk density due to the increased amount of porosity between the large grains of ZnO resulting from the rapid grain growth induced by the liquid phase sintering.The crystal size of ZnO decreases with increasing TiO2 doping.The addition of TiO2 improves the nonlinear coefficient and attains its maximum value at x = 0.7 mol% of TiO2,further addition negatively affects it.A decrease in capacitance consequently in the dielectric constant is recorded with increasing the frequency in a range of 30 kHz–200 kHz.The temperature and composition dependences of the dielectric constant and AC conductivity are also studied.The increase of temperature raises the dielectric constant because it increases ionic response to the field at any particular frequency.
文摘Heat transfer in an Eyring-Powell fluid that conducts electricity and flows past an exponentially growing sheet is considered.As the sheet is stretched in the x direction,the flow develops in the region with y>0.The problem is tackled through a set of partial differential equations accounting for Magnetohydrodynamics(MHD),radiation and Joule heating effects,which are converted into a set of equivalent ordinary differential equations through a similarity transformation.The converted problem is solved in MATLAB in the framework a fourth order accurate integration scheme.It is found that the thermal relaxation period is inversely proportional to the thickness of the thermal boundary layer,whereas the Eckert-number displays the opposite trend.As this characteristic number grows,the temperature within the channel increases.