Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic b...Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation,there is increasing evidence that endoplasmic reticulum(ER) stress-associated pathways play a role in the potentiation,initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment.展开更多
This article presents a numerical solution for the flow of a Newtonian fluid over an impermeable stretching sheet embedded in a porous medium with the power law surface velocity and variable thickness in the presence ...This article presents a numerical solution for the flow of a Newtonian fluid over an impermeable stretching sheet embedded in a porous medium with the power law surface velocity and variable thickness in the presence of thermal radiation. The flow is caused by non-linear stretching of a sheet. Thermal conductivity of the fluid is assumed to vary linearly with temperature. The governing partial differential equations （PDEs） are transformed into a system of coupled non-linear ordinary differential equations （ODEs） with appropriate boundary conditions for various physical parameters. The remaining system of ODEs is solved numerically using a differential transformation method （DTM）. The effects of the porous parameter, the wall thickness parameter, the radiation parameter, the thermal conductivity parameter, and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction and the Nusselt numbers are presented. Comparison of the obtained numerical results is made with previously published results in some special cases, with good agreement. The results obtained in this paper confirm the idea that DTM is a powerful mathematical tool and can be applied to a large class of linear and non-linear problems in different fields of science and engineering.展开更多
Direct hot rolled dual phase steel production represents a challenging route, compared with cold rolled and intercritical annealing process, due to complex and sophisticated control of the hot strip mill processing pa...Direct hot rolled dual phase steel production represents a challenging route, compared with cold rolled and intercritical annealing process, due to complex and sophisticated control of the hot strip mill processing parameters. Instead, high technology compact slab production plant offers economic advantages, adequate control and prompt use of the advanced thermomechanical controlled rolling. The current work aims to obtain different structures and tensile properties by physical simulation of direct hot rolled niobium micro alloyed dual phase low carbon steel by varying the metallurgical temperatures of hot strip mill plant. This starts with adaptation of the chemical analysis of a low carbon content to fall far from the undesired peritectic region to avoid slab cracking during casting. Thermodynamic and kinetics calculations by Thermo-Calc 2020 and JMat pro software are used to define the transformation’s temperatures Ae1 and Ae3 as well as processing temperatures;namely of reheating, finishing rolling, step cooling and coiling temperatures. The results show that the increase of finishing rolling temperature from 780<span style="white-space:nowrap;">°</span>C to 840<span style="white-space:nowrap;">°</span>C or decreasing either of step cooling duration at ferrite bay from 7 to 4 seconds, enhances yield and tensile strengths, all due to more martensite volume fraction formation. The yield and tensile strengths also increase with decreasing coiling temperature from 330<span style="white-space:nowrap;">°</span>C to 180<span style="white-space:nowrap;">°</span>C, which is explained due to the increase of dislocation densities resulted from the sudden shape change during martensite formation at the lower coiling temperature in additional to the self-tempering of martensite formed at higher coiling temperatures which soften the dual phase steel.展开更多
Diverse heritage architecture characterizes Port Said in Egypt,reflecting European and Arab influences.Suez Canal heritage villas comprise 25%of the total listed heritage buildings in the city.Thus,it is important to ...Diverse heritage architecture characterizes Port Said in Egypt,reflecting European and Arab influences.Suez Canal heritage villas comprise 25%of the total listed heritage buildings in the city.Thus,it is important to retrofit them,aligning with the Sustainable Development Goals(SDGs).By reviewing the previous literature related to the green retrofitting of heritage buildings,the(3Ts)framework can be considered a holistic framework that covers the latest trends due to its three components:targets,tools,and tasks,which help the success of the process through a holistic vision of supporting building information modeling(BIM)technologies and organizing stakeholders’involvement.This paper aims to apply the(3Ts)framework to Suez Canal heritage villas in Port Said,Egypt.The applied study is based on how stakeholders perceive their input and decision-making,measuring the climate parameters,proposing several green retrofits,and integrating them into green scenarios.Evaluation of scenarios is conducted by utilizing the Design Builder simulation software.Additionally,the Skelion plugin calculates the photovoltaic system’s(PVs)energy generation.The results indicated that the total energy savings could reach approximately 12%e74%and nearly 10%e73%CO₂emissions reduction without affecting heritage values.展开更多
Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechani...Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechanical model of the human body in a sitting posture without backrest for evaluating the vibration transmissibility and dynamic response to vertical vibration direction. In describing the human body motion, a three biomechanical models are discussed (two models are 4-DOF and one model 7-DOF). Optimization software based on stochastic techniques search methods, Genetic Algorithms (GAs), is employed to determine the human model parameters imposing some limit constraints on the model parameters. In addition, an objective function is formulated comprising the sum of errors between the computed and actual values (experimental data). The studied functions are the driving-point mechanical impedance, apparent mass and seat- to-head transmissibility functions. The optimization process increased the average goodness of fit and the results of studied functions became much closer to the target values (Experimental data). From the optimized model, the resonant frequencies of the driver parts computed on the basis of biodynamic response functions are found to be within close bounds to that expected for the human body.展开更多
Background: Conventional hemodialysis (HD) used in treating end stage renal disease (ESRD) can result in multiorgan insult including the eye-owing to the resultant reperfusion after the ischemic event. Optimization of...Background: Conventional hemodialysis (HD) used in treating end stage renal disease (ESRD) can result in multiorgan insult including the eye-owing to the resultant reperfusion after the ischemic event. Optimization of HD can be done using a process called remote ischemia which includes applying cycles of brief, nonlethal ischemia followed by reperfusion to one limb. This method sends signal to the end organs to prepare themselves for the upcoming ischemia thus preventing their injury. Aim: To evaluate the effect of remote ischemia preconditioning in HD on ophthalmological variables. Patients and Methods: A pre-post interventional analytical study conducted on patients receiving hemodialysis. Remote ischemia preconditioning was done before each HD session incorporating 3 cycles of alternating ischemia and reperfusion (5 minutes each) performed in the upper limb using sphygmomanometer cuff. Ophthalmic examination was done at baseline and 3 months after HD optimization. Assessment was done half to one hour pre- and post-session for visual acuity, corneal, conjunctival deposits, tear break up time (TBUT), anterior chamber depth and central macular thickness. Results: The study included 50 eyes of 25 patients with almost equal gender distribution and mean age of 37.52 ± 9.824 years. They were maintained on hemodialysis for median 10 years (range 3-25 years). The commonest cause of ESRD was hypertension. The studied ocular parameters showed insignificant change after pre-conditioned HD except for TBUT that was statistically longer (p = 0.018). Conclusion: Optimization of hemodialysis using remote ischemia does not seem to have significant ocular effect apart from prolonged TBUT. .展开更多
Background:The impact of chronic hepatitis C (CHC) on bone mineral density (BMD) has been well studied in adults with a relative paucity of data in children,especially concerning effect of treatment with pegylated int...Background:The impact of chronic hepatitis C (CHC) on bone mineral density (BMD) has been well studied in adults with a relative paucity of data in children,especially concerning effect of treatment with pegylated interferon (PEG-IFN) plus ribavirin (RV).In the current work,we assessed prospectively changes in BMD in children with CHC before,during,and after treatment.Methods:Forty-six consecutive children with noncirrhotic genotype 4 CHC were subjected to dual-energy X-ray absorptiometry at baseline,24 weeks,48 weeks of therapy and 24 weeks after treatment.BMD,bone mineral content (BMC),and Z score of lumbar spine (L2-L4) were reported.Tanner pubertal stage,viral load,liver function tests,serum calcium,phosphorus,alkaline phosphatase,parathyroid hormone,and liver histopathology were assessed in all included children.Results:Thirty (65.2%) patients had normal BMD,10 (21.7%) were at risk for low BMD,and 6 (13.1%) had low BMD for chronological age.Patients with low BMD were significantly older (P=0.001),with higher frequency of delayed puberty than other groups (P=0.002).Baseline densitometric parameters (BMD & BMC) were significantly positively correlated with patients' age,weight,height,body mass index and hemoglobin level;while they were insignificantly correlated with basal viral load,histopathology activity index and fibrosis score.Densitometric parameters improved significantly on PEG-IFN plus RV treatment,this improvement was found to be sustainable 24 weeks after therapy.Conclusions:Low BMD is detectable in a proportion of CHC children.Antiviral therapy leads to a sustainable increase in BMD.展开更多
FeNiCrCoSi_(x) and FeNiCrCoTi_(x)(x=0,0.3,0.6,and 0.9 wt.%)high entropy alloys(HEAs)were prepared via the powder metallurgy technique.A homogenous distribution of the elements in all alloys due to the formation of a s...FeNiCrCoSi_(x) and FeNiCrCoTi_(x)(x=0,0.3,0.6,and 0.9 wt.%)high entropy alloys(HEAs)were prepared via the powder metallurgy technique.A homogenous distribution of the elements in all alloys due to the formation of a solid solution phase is observed.The density and hardness of the prepared HEAs are improved by Si and Ti additions,compared to FeNiCrCo HEA.The wear rate of the prepared alloys was studied at different loads and the results indicate that the alloys that contain 0.3 wt.%Si and 0.9 wt.%Ti have the lowest wear rates.X-ray diffraction,SEM,and EDX were used to understand the phases,grain sizes,and microstructures in different investigated HEAs.The effects of Si and Ti content on the corrosion behavior and surface morphologies of sintered FeNiCrCoSi_(x) and FeNiCrCoTi_(x) HEAs were studied by immersion in H_(2)SO_(4),HNO_(3),and HCl solutions.Uniform corrosion and localized pitting are observed in different sizes in the corrosive media used.Because of the smaller pit size and the reduced pit density,the FeNiCrCoSi_(0.3) HEA has an excellent microstructure.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)accounts for 8.2%of all cancer-related deaths worldwide.Being a vascular tumor,vascular endothelial growth factor(VEGF)plays a vital role in HCC pathogenesis,growth,and spread.A...BACKGROUND Hepatocellular carcinoma(HCC)accounts for 8.2%of all cancer-related deaths worldwide.Being a vascular tumor,vascular endothelial growth factor(VEGF)plays a vital role in HCC pathogenesis,growth,and spread.AIM To determine the accuracy of serum VEGF and VEGF/platelet(PLT)as tumor markers in the early detection of HCC cases in patients with hepatitis C virus(HCV)-related liver cirrhosis.METHODS We conducted a case-control study with HCV patients from the outpatient and inpatient hepatology clinics.Patients were classified into three groups:(1)HCC group;(2)Cirrhosis group;and(3)HCV without cirrhosis(control group).Patients were clinically evaluated,and blood samples were drawn for the analysis;serum VEGF levels were measured by a specific VEGF human recombinant enzyme-linked immunosorbent assay kit.Data from the three study groups were compared by the one-way analysis of variance or Kruskal-Wallis test.Receivers operating characteristic curves were constructed to determine the optimal cut-off values of alpha fetoprotein(AFP),VEGF,and VEGF/PLT that provided the best diagnostic accuracy.The sensitivity and specificity at the optimal cut-off value of each biomarker were then calculated.RESULTS This study included one hundred patients(HCC,cirrhosis,and control groups:n=40,30,30,respectively).HCC patients had significantly higher serum VEGF and VEGF/PLT levels than the non-HCC groups(P=0.001).Serum VEGF and VEGF/PLT showed significant positive correlations with and HCC tumor size,stage,vascular invasion,and Child-Pugh classification.Moreover,a VEGF cut-off the value of 250 pg/mL provided 80%sensitivity and 81.7%specificity for discriminating HCC patient from non-HCC patients.Similarly,the ratio of VEGF/PLT provided sensitivity and specificity of 77.5%and 80%,respectively which is higher than the accuracy provided by AFP.The combination of AFP,VEGF,and VEGF/PLT increases the accuracy of diagnosing HCC to>95%.CONCLUSION In HCV patients,serum VEGF and VEGF/PLT separately or in combination with AFP are reliable bi展开更多
The linear seat suspension is considered due to the low cost consideration therefore, the optimal linear seat suspension design method can be used for this purpose. In this paper, the design of a passive vehicle seat ...The linear seat suspension is considered due to the low cost consideration therefore, the optimal linear seat suspension design method can be used for this purpose. In this paper, the design of a passive vehicle seat suspension system was handled in the framework of linear optimization. The variance of the dynamic load resulting from the vibrating vehicle operating at a constant speed was used as the performance measure of a suspension system. Using 4-DOF human body model developed by Abbas et al., with linear seat suspension and coupled with half car model. A genetic algorithm is applied to solve the linear optimization problem. The optimal design parameters of the seat suspension systems obtained are kse = 3 012.5 N/m and cse = 1 210.4 N.s/m, respectively.展开更多
Objective: The aim of the present study is to discriminate functions for sex determination in a subjected sample of the Egyptian population using the morphology of metacarpals and phalanges for gender comparison. Furt...Objective: The aim of the present study is to discriminate functions for sex determination in a subjected sample of the Egyptian population using the morphology of metacarpals and phalanges for gender comparison. Furthermore, the measurements discussed in this study will aid in predicting the differentiation independently and guaranteeing sex determination in the subjected population individually. Methods: Forty measurements were taken from the right metacarpals and phalangeal bones of 100 subjects, whose ages ranged from 19 to 60. Moreover, the measurements of nine metacarpals and four phalangeal bones were used for sex discrimination in each sample population. Results: Males had significantly greater mean values (P < 0.05) for the lengths of the metacarpals and the proximal phalangeal bones of all right-hand fingers than females. The cut-off value and the accuracy percentage for precise sex classification of males and females using individual and grouped bones showed that a value higher than the marking point classified an individual as male and that a lower value suggested female. Besides, the multiple stepwise discriminant functional analysis of the most predictable internal variables of the metacarpals revealed a cross-validated sex classification accuracy of 100%. In contrast, the most predictable internal variables of the phalanges showed a cross-validated sex classification accuracy of 93%. Conclusion: The results revealed a new forensic suggestion for the determination of sex based on the measurements of the metacarpals and the phalanges. Moreover, various discriminant equations were applied for the declaration of this conceivable recommendation.展开更多
The Lie group method is applied to present an analysis of the magneto hydro-dynamics（MHD） steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of ther...The Lie group method is applied to present an analysis of the magneto hydro-dynamics（MHD） steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of thermal radiation.By using the Lie group method,we have presented the transformation groups for the problem apart from the scaling group.The application of this method reduces the partial differential equations（PDEs） with their boundary conditions governing the flow and heat transfer to a system of nonlinear ordinary differential equations（ODEs） with appropriate boundary conditions.The resulting nonlinear system of ODEs is solved numerically using the implicit finite difference method（FDM）.The local skin-friction coefficients and the local Nusselt numbers for different physical parameters are presented in a table.展开更多
In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus (HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders incl...In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus (HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders including those with pruritus as a symptom. Pruritus is frequently associated with the development of chronic liver diseases such as cholestasis and chronic viral infection, and the accumulation of bile acids in patients’ sera and tissues as a consequence of liver damage is considered the main cause of pruritus. In addition to their role in dietary lipid absorption, bile acids can trigger the activation of specific receptors, such as the G protein-coupled bile acid receptor (GPBA/ TGR5). These types of receptors are known to play a crucial role in the modulation of the systemic actions of bile acids. TGR5 expression in primary sensory neurons triggers the activation of the transient receptor potential vanilloid 1 (TRPV1) leading to the induction of pruritus by an unknown mechanism. Although the pathologic phenomenon of pruritus is common, there is no uniformly effective therapy available. Understanding the mechanisms regulating the occurrence of pruritus together with the conduction of large-scale clinical and evidence-based studies, may help to create a standard treatment protocol. This review focuses on the etiopathogenesis and treatment strategies of pruritus associated with chronic HCV infection.展开更多
The effects of variable fluid properties and variable heat flux on the flow and heat transfer of a non-Newtonian Maxwell fluid over an unsteady stretching sheet in the presence of slip velocity have been studied. The ...The effects of variable fluid properties and variable heat flux on the flow and heat transfer of a non-Newtonian Maxwell fluid over an unsteady stretching sheet in the presence of slip velocity have been studied. The governing differential equations are transformed into a set of coupled non-linear ordinary differential equations and then solved with a numerical technique using appropriate boundary conditions for various physical parameters. The numerical solution for the governing non-linear boundary value problem is based on applying the fourth-order Runge-Kutta method coupled with the shooting technique over the entire range of physical parameters. The effects of various parameters like the viscosity parameter, thermal conductivity parameter, unsteadiness parameter, slip velocity parameter, the Deborah number, and the Prandtl number on the flow and temperature profiles as well as on the local skin-friction coefficient and the local Nusselt number are presented and discussed. Comparison of numerical results is made with the earlier published results under limiting cases.展开更多
Aluminum （Al）-based aluminum oxide （Al2O3） and silicon carbide （SIC） particles hybrid metal matrix com- posites were processed by powder metallurgy technique, followed by sintering at 500 ℃ and then hot extrusi...Aluminum （Al）-based aluminum oxide （Al2O3） and silicon carbide （SIC） particles hybrid metal matrix com- posites were processed by powder metallurgy technique, followed by sintering at 500 ℃ and then hot extrusion. The tribological properties of these composites with different weight fractions of Al2O3 and SiC were investigated; extrusion process significantly reduces the extent of porosity after cold compaction and sintering processes. Hybridization of the two reinforcements improved hardness and wear resistance of the composites. With an increase in SiC content, hardness was increased and consequently the wear resistance was enhanced also. Scanning electron microscopy observations show a better interfacial bond between matrix and reinforcements and a better distribution of the reinforcements.展开更多
This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid...This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid properties, slip velocity, and internal heat generation/absorption. The flow in boundary layer is considered to be generated solely by the stretching of the sheet adjacent to porous medium with boundary wall slip condition. Highly nonlinear momentum and thermal boundary layer equations governing the flow and heat transfer are reduced to set of nonlinear ordinary differential equations by appropriate transformation. The resulting ODEs are successfully solved numerically with the help of shooting method. Graphical results are shown for non-dimensional velocities and temperature. The effects of heat generation/absorption parameter, the porous parameter, the viscoelastic parameter, velocity slip parameter, variable thermal conductivity and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction coefficient and Nusselt number are presented. Comparison of numerical results is made with the earlier published results under limiting cases.展开更多
Joints of copper and stainless steels are used in a er ospace applications. Production of these joints by fusion welding faces many dif ficulties. This may be due to the differences in their physical, metallurgical a ...Joints of copper and stainless steels are used in a er ospace applications. Production of these joints by fusion welding faces many dif ficulties. This may be due to the differences in their physical, metallurgical a nd mechanical properties. Electron Beam Welding (EBW) process has been found to be especially well suited in this area. Selection of the appropriate welding par ameters needs thorough investigations. These parameters include: preheat tempera ture (℃), welding current (I w), focusing current (I F), welding spee d (V), height between the gun and workpiece surface (H), scan width (S w) and shift distance (S). The present work aims firstly, setting the pr oper welding conditions to get sound joint between commercially pure copper (C10 200) and AISI 316 stainless steel plates 8 mm thickness. Secondly, investigate t he effect of Electron Beam (EB) shift, single-sided and double-sided welds on the mechanical, metallurgical and chemical properties of the weld bead. Due to t he high difference in thermal conductivity between copper and stainless steel, E lectron Beam (EB) was shifted towards copper with different values. These values were ranged from 0.3 to 0.9 mm in welding without preheating of copper plate an d from 0.1 to 0.4 mm with preheating. Number of joints were welded using variabl e EBW parameters in view to obtain the sound weld bead. These parameters are as follows: gradual reduction I w=51 to 49 mA, I F=845 mA, V=8 mm/sec , H=130 mm, S w=500 μm and S=0.4 mm. The investigation has shown t hat, the copper (C10200) plate must be preheated to get sound welded joint with AISI 316 stainless steel using the EBW process. The tensile fracture in all wel ded samples occurred in copper plate away from the weld bead. This reflects that the weld bead tensile strength is greater than the copper strength. The EB shif t has slight effect on hardness distribution through weld bead. The hardness val ue (H v) reduces in gradual manner from stainless steel hardness to copper one. The EB shift distance has no sig展开更多
Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examinatio...Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examination to detect G.lamblia infection,and to exclude other intestinal pathogens.On the basis of their microscopic findings,a group of 80 children were chosen as giardiasis cases,another 80 children were confirmed as Giardia free control group by immunochromatographic test,and the remaining children were excluded.Both giardiasis and control groups were then subjected to blood examination to identify their genetic type of HLA-DRB1 alleles.Results:HLA class-ⅡDRB1*03:01 and DRB1*13:01 alleles were significantly associated with G.lamblia infection(P<0.001 for each variable).On the other hand,HLA class-ⅡDRB1*04:02,DRB1*10:01,DRB1*14:01 and DRB1*15:01 alleles were significantly demonstrated in Giardia free children.However,other HLA-DRB1 alleles did not show any significant association with giardiasis.Conclusions:HLA class-ⅡDRB1*03,DRB1*13,DRB1*04,DRB1*10,DRB1*14 and DRB1*15 alleles may be involved in the establishment of host immune response to G.lamblia infection.展开更多
文摘Melanoma is the most aggressive form of skin cancer.Disrupted intracellular signaling pathways are responsible for melanoma's extraordinary resistance to current chemotherapeutic modalities. The pathophysiologic basis for resistance to both chemo- and radiation therapy is rooted in altered genetic and epigenetic mechanisms that, in turn, result in the impairing of cell death machinery and/or excessive activation of cell growth and survival-dependent pathways. Although most current melanoma therapies target mitochondrial dysregulation,there is increasing evidence that endoplasmic reticulum(ER) stress-associated pathways play a role in the potentiation,initiation and maintenance of cell death machinery and autophagy. This review focuses on the reliability of ER-associated pathways as therapeutic targets for melanoma treatment.
文摘This article presents a numerical solution for the flow of a Newtonian fluid over an impermeable stretching sheet embedded in a porous medium with the power law surface velocity and variable thickness in the presence of thermal radiation. The flow is caused by non-linear stretching of a sheet. Thermal conductivity of the fluid is assumed to vary linearly with temperature. The governing partial differential equations （PDEs） are transformed into a system of coupled non-linear ordinary differential equations （ODEs） with appropriate boundary conditions for various physical parameters. The remaining system of ODEs is solved numerically using a differential transformation method （DTM）. The effects of the porous parameter, the wall thickness parameter, the radiation parameter, the thermal conductivity parameter, and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction and the Nusselt numbers are presented. Comparison of the obtained numerical results is made with previously published results in some special cases, with good agreement. The results obtained in this paper confirm the idea that DTM is a powerful mathematical tool and can be applied to a large class of linear and non-linear problems in different fields of science and engineering.
文摘Direct hot rolled dual phase steel production represents a challenging route, compared with cold rolled and intercritical annealing process, due to complex and sophisticated control of the hot strip mill processing parameters. Instead, high technology compact slab production plant offers economic advantages, adequate control and prompt use of the advanced thermomechanical controlled rolling. The current work aims to obtain different structures and tensile properties by physical simulation of direct hot rolled niobium micro alloyed dual phase low carbon steel by varying the metallurgical temperatures of hot strip mill plant. This starts with adaptation of the chemical analysis of a low carbon content to fall far from the undesired peritectic region to avoid slab cracking during casting. Thermodynamic and kinetics calculations by Thermo-Calc 2020 and JMat pro software are used to define the transformation’s temperatures Ae1 and Ae3 as well as processing temperatures;namely of reheating, finishing rolling, step cooling and coiling temperatures. The results show that the increase of finishing rolling temperature from 780<span style="white-space:nowrap;">°</span>C to 840<span style="white-space:nowrap;">°</span>C or decreasing either of step cooling duration at ferrite bay from 7 to 4 seconds, enhances yield and tensile strengths, all due to more martensite volume fraction formation. The yield and tensile strengths also increase with decreasing coiling temperature from 330<span style="white-space:nowrap;">°</span>C to 180<span style="white-space:nowrap;">°</span>C, which is explained due to the increase of dislocation densities resulted from the sudden shape change during martensite formation at the lower coiling temperature in additional to the self-tempering of martensite formed at higher coiling temperatures which soften the dual phase steel.
文摘Diverse heritage architecture characterizes Port Said in Egypt,reflecting European and Arab influences.Suez Canal heritage villas comprise 25%of the total listed heritage buildings in the city.Thus,it is important to retrofit them,aligning with the Sustainable Development Goals(SDGs).By reviewing the previous literature related to the green retrofitting of heritage buildings,the(3Ts)framework can be considered a holistic framework that covers the latest trends due to its three components:targets,tools,and tasks,which help the success of the process through a holistic vision of supporting building information modeling(BIM)technologies and organizing stakeholders’involvement.This paper aims to apply the(3Ts)framework to Suez Canal heritage villas in Port Said,Egypt.The applied study is based on how stakeholders perceive their input and decision-making,measuring the climate parameters,proposing several green retrofits,and integrating them into green scenarios.Evaluation of scenarios is conducted by utilizing the Design Builder simulation software.Additionally,the Skelion plugin calculates the photovoltaic system’s(PVs)energy generation.The results indicated that the total energy savings could reach approximately 12%e74%and nearly 10%e73%CO₂emissions reduction without affecting heritage values.
文摘Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechanical model of the human body in a sitting posture without backrest for evaluating the vibration transmissibility and dynamic response to vertical vibration direction. In describing the human body motion, a three biomechanical models are discussed (two models are 4-DOF and one model 7-DOF). Optimization software based on stochastic techniques search methods, Genetic Algorithms (GAs), is employed to determine the human model parameters imposing some limit constraints on the model parameters. In addition, an objective function is formulated comprising the sum of errors between the computed and actual values (experimental data). The studied functions are the driving-point mechanical impedance, apparent mass and seat- to-head transmissibility functions. The optimization process increased the average goodness of fit and the results of studied functions became much closer to the target values (Experimental data). From the optimized model, the resonant frequencies of the driver parts computed on the basis of biodynamic response functions are found to be within close bounds to that expected for the human body.
文摘Background: Conventional hemodialysis (HD) used in treating end stage renal disease (ESRD) can result in multiorgan insult including the eye-owing to the resultant reperfusion after the ischemic event. Optimization of HD can be done using a process called remote ischemia which includes applying cycles of brief, nonlethal ischemia followed by reperfusion to one limb. This method sends signal to the end organs to prepare themselves for the upcoming ischemia thus preventing their injury. Aim: To evaluate the effect of remote ischemia preconditioning in HD on ophthalmological variables. Patients and Methods: A pre-post interventional analytical study conducted on patients receiving hemodialysis. Remote ischemia preconditioning was done before each HD session incorporating 3 cycles of alternating ischemia and reperfusion (5 minutes each) performed in the upper limb using sphygmomanometer cuff. Ophthalmic examination was done at baseline and 3 months after HD optimization. Assessment was done half to one hour pre- and post-session for visual acuity, corneal, conjunctival deposits, tear break up time (TBUT), anterior chamber depth and central macular thickness. Results: The study included 50 eyes of 25 patients with almost equal gender distribution and mean age of 37.52 ± 9.824 years. They were maintained on hemodialysis for median 10 years (range 3-25 years). The commonest cause of ESRD was hypertension. The studied ocular parameters showed insignificant change after pre-conditioned HD except for TBUT that was statistically longer (p = 0.018). Conclusion: Optimization of hemodialysis using remote ischemia does not seem to have significant ocular effect apart from prolonged TBUT. .
文摘Background:The impact of chronic hepatitis C (CHC) on bone mineral density (BMD) has been well studied in adults with a relative paucity of data in children,especially concerning effect of treatment with pegylated interferon (PEG-IFN) plus ribavirin (RV).In the current work,we assessed prospectively changes in BMD in children with CHC before,during,and after treatment.Methods:Forty-six consecutive children with noncirrhotic genotype 4 CHC were subjected to dual-energy X-ray absorptiometry at baseline,24 weeks,48 weeks of therapy and 24 weeks after treatment.BMD,bone mineral content (BMC),and Z score of lumbar spine (L2-L4) were reported.Tanner pubertal stage,viral load,liver function tests,serum calcium,phosphorus,alkaline phosphatase,parathyroid hormone,and liver histopathology were assessed in all included children.Results:Thirty (65.2%) patients had normal BMD,10 (21.7%) were at risk for low BMD,and 6 (13.1%) had low BMD for chronological age.Patients with low BMD were significantly older (P=0.001),with higher frequency of delayed puberty than other groups (P=0.002).Baseline densitometric parameters (BMD & BMC) were significantly positively correlated with patients' age,weight,height,body mass index and hemoglobin level;while they were insignificantly correlated with basal viral load,histopathology activity index and fibrosis score.Densitometric parameters improved significantly on PEG-IFN plus RV treatment,this improvement was found to be sustainable 24 weeks after therapy.Conclusions:Low BMD is detectable in a proportion of CHC children.Antiviral therapy leads to a sustainable increase in BMD.
文摘FeNiCrCoSi_(x) and FeNiCrCoTi_(x)(x=0,0.3,0.6,and 0.9 wt.%)high entropy alloys(HEAs)were prepared via the powder metallurgy technique.A homogenous distribution of the elements in all alloys due to the formation of a solid solution phase is observed.The density and hardness of the prepared HEAs are improved by Si and Ti additions,compared to FeNiCrCo HEA.The wear rate of the prepared alloys was studied at different loads and the results indicate that the alloys that contain 0.3 wt.%Si and 0.9 wt.%Ti have the lowest wear rates.X-ray diffraction,SEM,and EDX were used to understand the phases,grain sizes,and microstructures in different investigated HEAs.The effects of Si and Ti content on the corrosion behavior and surface morphologies of sintered FeNiCrCoSi_(x) and FeNiCrCoTi_(x) HEAs were studied by immersion in H_(2)SO_(4),HNO_(3),and HCl solutions.Uniform corrosion and localized pitting are observed in different sizes in the corrosive media used.Because of the smaller pit size and the reduced pit density,the FeNiCrCoSi_(0.3) HEA has an excellent microstructure.
基金The study was reviewed and approved by(Egypt Center for research and regenerative medicine,and Al Azhar University)Institutional Review Board,No.IRB 00012517.
文摘BACKGROUND Hepatocellular carcinoma(HCC)accounts for 8.2%of all cancer-related deaths worldwide.Being a vascular tumor,vascular endothelial growth factor(VEGF)plays a vital role in HCC pathogenesis,growth,and spread.AIM To determine the accuracy of serum VEGF and VEGF/platelet(PLT)as tumor markers in the early detection of HCC cases in patients with hepatitis C virus(HCV)-related liver cirrhosis.METHODS We conducted a case-control study with HCV patients from the outpatient and inpatient hepatology clinics.Patients were classified into three groups:(1)HCC group;(2)Cirrhosis group;and(3)HCV without cirrhosis(control group).Patients were clinically evaluated,and blood samples were drawn for the analysis;serum VEGF levels were measured by a specific VEGF human recombinant enzyme-linked immunosorbent assay kit.Data from the three study groups were compared by the one-way analysis of variance or Kruskal-Wallis test.Receivers operating characteristic curves were constructed to determine the optimal cut-off values of alpha fetoprotein(AFP),VEGF,and VEGF/PLT that provided the best diagnostic accuracy.The sensitivity and specificity at the optimal cut-off value of each biomarker were then calculated.RESULTS This study included one hundred patients(HCC,cirrhosis,and control groups:n=40,30,30,respectively).HCC patients had significantly higher serum VEGF and VEGF/PLT levels than the non-HCC groups(P=0.001).Serum VEGF and VEGF/PLT showed significant positive correlations with and HCC tumor size,stage,vascular invasion,and Child-Pugh classification.Moreover,a VEGF cut-off the value of 250 pg/mL provided 80%sensitivity and 81.7%specificity for discriminating HCC patient from non-HCC patients.Similarly,the ratio of VEGF/PLT provided sensitivity and specificity of 77.5%and 80%,respectively which is higher than the accuracy provided by AFP.The combination of AFP,VEGF,and VEGF/PLT increases the accuracy of diagnosing HCC to>95%.CONCLUSION In HCV patients,serum VEGF and VEGF/PLT separately or in combination with AFP are reliable bi
文摘The linear seat suspension is considered due to the low cost consideration therefore, the optimal linear seat suspension design method can be used for this purpose. In this paper, the design of a passive vehicle seat suspension system was handled in the framework of linear optimization. The variance of the dynamic load resulting from the vibrating vehicle operating at a constant speed was used as the performance measure of a suspension system. Using 4-DOF human body model developed by Abbas et al., with linear seat suspension and coupled with half car model. A genetic algorithm is applied to solve the linear optimization problem. The optimal design parameters of the seat suspension systems obtained are kse = 3 012.5 N/m and cse = 1 210.4 N.s/m, respectively.
文摘Objective: The aim of the present study is to discriminate functions for sex determination in a subjected sample of the Egyptian population using the morphology of metacarpals and phalanges for gender comparison. Furthermore, the measurements discussed in this study will aid in predicting the differentiation independently and guaranteeing sex determination in the subjected population individually. Methods: Forty measurements were taken from the right metacarpals and phalangeal bones of 100 subjects, whose ages ranged from 19 to 60. Moreover, the measurements of nine metacarpals and four phalangeal bones were used for sex discrimination in each sample population. Results: Males had significantly greater mean values (P < 0.05) for the lengths of the metacarpals and the proximal phalangeal bones of all right-hand fingers than females. The cut-off value and the accuracy percentage for precise sex classification of males and females using individual and grouped bones showed that a value higher than the marking point classified an individual as male and that a lower value suggested female. Besides, the multiple stepwise discriminant functional analysis of the most predictable internal variables of the metacarpals revealed a cross-validated sex classification accuracy of 100%. In contrast, the most predictable internal variables of the phalanges showed a cross-validated sex classification accuracy of 93%. Conclusion: The results revealed a new forensic suggestion for the determination of sex based on the measurements of the metacarpals and the phalanges. Moreover, various discriminant equations were applied for the declaration of this conceivable recommendation.
文摘The Lie group method is applied to present an analysis of the magneto hydro-dynamics（MHD） steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of thermal radiation.By using the Lie group method,we have presented the transformation groups for the problem apart from the scaling group.The application of this method reduces the partial differential equations（PDEs） with their boundary conditions governing the flow and heat transfer to a system of nonlinear ordinary differential equations（ODEs） with appropriate boundary conditions.The resulting nonlinear system of ODEs is solved numerically using the implicit finite difference method（FDM）.The local skin-friction coefficients and the local Nusselt numbers for different physical parameters are presented in a table.
文摘In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus (HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders including those with pruritus as a symptom. Pruritus is frequently associated with the development of chronic liver diseases such as cholestasis and chronic viral infection, and the accumulation of bile acids in patients’ sera and tissues as a consequence of liver damage is considered the main cause of pruritus. In addition to their role in dietary lipid absorption, bile acids can trigger the activation of specific receptors, such as the G protein-coupled bile acid receptor (GPBA/ TGR5). These types of receptors are known to play a crucial role in the modulation of the systemic actions of bile acids. TGR5 expression in primary sensory neurons triggers the activation of the transient receptor potential vanilloid 1 (TRPV1) leading to the induction of pruritus by an unknown mechanism. Although the pathologic phenomenon of pruritus is common, there is no uniformly effective therapy available. Understanding the mechanisms regulating the occurrence of pruritus together with the conduction of large-scale clinical and evidence-based studies, may help to create a standard treatment protocol. This review focuses on the etiopathogenesis and treatment strategies of pruritus associated with chronic HCV infection.
文摘The effects of variable fluid properties and variable heat flux on the flow and heat transfer of a non-Newtonian Maxwell fluid over an unsteady stretching sheet in the presence of slip velocity have been studied. The governing differential equations are transformed into a set of coupled non-linear ordinary differential equations and then solved with a numerical technique using appropriate boundary conditions for various physical parameters. The numerical solution for the governing non-linear boundary value problem is based on applying the fourth-order Runge-Kutta method coupled with the shooting technique over the entire range of physical parameters. The effects of various parameters like the viscosity parameter, thermal conductivity parameter, unsteadiness parameter, slip velocity parameter, the Deborah number, and the Prandtl number on the flow and temperature profiles as well as on the local skin-friction coefficient and the local Nusselt number are presented and discussed. Comparison of numerical results is made with the earlier published results under limiting cases.
文摘Aluminum （Al）-based aluminum oxide （Al2O3） and silicon carbide （SIC） particles hybrid metal matrix com- posites were processed by powder metallurgy technique, followed by sintering at 500 ℃ and then hot extrusion. The tribological properties of these composites with different weight fractions of Al2O3 and SiC were investigated; extrusion process significantly reduces the extent of porosity after cold compaction and sintering processes. Hybridization of the two reinforcements improved hardness and wear resistance of the composites. With an increase in SiC content, hardness was increased and consequently the wear resistance was enhanced also. Scanning electron microscopy observations show a better interfacial bond between matrix and reinforcements and a better distribution of the reinforcements.
文摘This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid properties, slip velocity, and internal heat generation/absorption. The flow in boundary layer is considered to be generated solely by the stretching of the sheet adjacent to porous medium with boundary wall slip condition. Highly nonlinear momentum and thermal boundary layer equations governing the flow and heat transfer are reduced to set of nonlinear ordinary differential equations by appropriate transformation. The resulting ODEs are successfully solved numerically with the help of shooting method. Graphical results are shown for non-dimensional velocities and temperature. The effects of heat generation/absorption parameter, the porous parameter, the viscoelastic parameter, velocity slip parameter, variable thermal conductivity and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction coefficient and Nusselt number are presented. Comparison of numerical results is made with the earlier published results under limiting cases.
文摘Joints of copper and stainless steels are used in a er ospace applications. Production of these joints by fusion welding faces many dif ficulties. This may be due to the differences in their physical, metallurgical a nd mechanical properties. Electron Beam Welding (EBW) process has been found to be especially well suited in this area. Selection of the appropriate welding par ameters needs thorough investigations. These parameters include: preheat tempera ture (℃), welding current (I w), focusing current (I F), welding spee d (V), height between the gun and workpiece surface (H), scan width (S w) and shift distance (S). The present work aims firstly, setting the pr oper welding conditions to get sound joint between commercially pure copper (C10 200) and AISI 316 stainless steel plates 8 mm thickness. Secondly, investigate t he effect of Electron Beam (EB) shift, single-sided and double-sided welds on the mechanical, metallurgical and chemical properties of the weld bead. Due to t he high difference in thermal conductivity between copper and stainless steel, E lectron Beam (EB) was shifted towards copper with different values. These values were ranged from 0.3 to 0.9 mm in welding without preheating of copper plate an d from 0.1 to 0.4 mm with preheating. Number of joints were welded using variabl e EBW parameters in view to obtain the sound weld bead. These parameters are as follows: gradual reduction I w=51 to 49 mA, I F=845 mA, V=8 mm/sec , H=130 mm, S w=500 μm and S=0.4 mm. The investigation has shown t hat, the copper (C10200) plate must be preheated to get sound welded joint with AISI 316 stainless steel using the EBW process. The tensile fracture in all wel ded samples occurred in copper plate away from the weld bead. This reflects that the weld bead tensile strength is greater than the copper strength. The EB shif t has slight effect on hardness distribution through weld bead. The hardness val ue (H v) reduces in gradual manner from stainless steel hardness to copper one. The EB shift distance has no sig
文摘Objective:To compare the genotype frequencies of HLA class-ⅡDRB1 alleles in Giardia(G.)lamblia-infected children.Methods:A total of 490 Egyptian children aged 2-16 years were subjected to microscopic stool examination to detect G.lamblia infection,and to exclude other intestinal pathogens.On the basis of their microscopic findings,a group of 80 children were chosen as giardiasis cases,another 80 children were confirmed as Giardia free control group by immunochromatographic test,and the remaining children were excluded.Both giardiasis and control groups were then subjected to blood examination to identify their genetic type of HLA-DRB1 alleles.Results:HLA class-ⅡDRB1*03:01 and DRB1*13:01 alleles were significantly associated with G.lamblia infection(P<0.001 for each variable).On the other hand,HLA class-ⅡDRB1*04:02,DRB1*10:01,DRB1*14:01 and DRB1*15:01 alleles were significantly demonstrated in Giardia free children.However,other HLA-DRB1 alleles did not show any significant association with giardiasis.Conclusions:HLA class-ⅡDRB1*03,DRB1*13,DRB1*04,DRB1*10,DRB1*14 and DRB1*15 alleles may be involved in the establishment of host immune response to G.lamblia infection.
