Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked sheet.With the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is illustrated.The resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity transformations.The transformed differential equations are solved analytically.Impacts of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted graphically.The skin friction and Nusselt number were also evaluated.In addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching one.Further,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O nanofluid.Furthermore,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

Three-dimensional mixed convection stagnation-point fow past a vertical surface with second-order slip velocity

This study is concerned with the three-dimensional(3D)stagnation-point for the mixed convection flow past a vertical surface considering the first-order and secondorder velocity slips.To the authors’knowledge,this is the first study presenting this very interesting analysis.Nonlinear partial differential equations for the flow problem are transformed into nonlinear ordinary differential equations(ODEs)by using appropriate similarity transformation.These ODEs with the corresponding boundary conditions are numerically solved by utilizing the bvp4c solver in MATLAB programming language.The effects of the governing parameters on the non-dimensional velocity profiles,temperature profiles,skin friction coefficients,and the local Nusselt number are presented in detail through a series of graphs and tables.Interestingly,it is reported that the reduced skin friction coefficient decreases for the assisting flow situation and increases for the opposing flow situation.The numerical computations of the present work are compared with those from other research available in specific situations,and an excellent consensus is observed.Another exciting feature for this work is the existence of dual solutions.An important remark is that the dual solutions exist for both assisting and opposing flows.A linear stability analysis is performed showing that one solution is stable and the other solution is not stable.We notice that the mixed convection and velocity slip parameters have strong effects on the flow characteristics.These effects are depicted in graphs and discussed in this paper.The obtained results show that the first-order and second-order slip parameters have a considerable effect on the flow,as well as on the heat transfer characteristics.

Psychosocial determinants of irritable bowel syndrome

From a pure motor disorder of the bowel,in the past few years,irritable bowel syndrome (IBS) has become a multifactorial disease that implies visceral hypersensitivity,alterations at the level of nervous and humoral communications between the enteric nervous system and the central nervous system,alteration of the gut microflora,an increased intestinal permeability and minimum intestinal inflammation.Psychological and social factors can interfere with the communication between the central and enteric nervous systems,and there is proof that they are involved in the onset of IBS and influence the response to treatment and outcome.There is evidence that abuse history and stressful life events are involved in the onset of functional gastrointestinal disorders.In order to explain clustering of IBS in families,genetic factors and social learning mechanisms have been proposed.The psychological features,such as anxiety,depression as well as the comorbid psychiatric disorders,health beliefs and coping of patients with IBS are discussed in relation to the symptoms and outcome.

Learning tasks as a possible treatment for DNA lesions induced by oxidative stress in hippocampal neurons

Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc- tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path- ways to counteract these effects, with base excision repair being responsible for repairing one of the major base lesions （8-oxoG） in all organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer＇s dis- ease-like disease, but given its complexity it is not clear what specific aspect of enriched environ- ment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of base excision repair. Based on the evidence, we propose that learning tasks such as novel object recognition could be tested as possible methods of base excision repair fa- cilitation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effec- tive, it could be the start for designing similar tasks for humans, as a behavioral therapeutic com- plement to the classical drug-based therapy in treating neurodegenerative disorders.

Unsteady MHD flow and heat transfer near stagnation point over a stretching/shrinking sheet in porous medium filled with a nanofluid

In this article, the unsteady magnetohydrodynamic （MHD） stagnation point flow and heat transfer of a nanofluid over a stretching/shrinking sheet is investigated numerically. The similarity solution is used to reduce the governing system of partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using the fourth-order Runge-Kutta method with shooting technique. The ambient fluid velocity, stretching/shrinking velocity of sheet, and the wall temperature are assumed to vary linearly with the distance from the stagnation point. To investigate the influence of various pertinent parameters, graphical results for the local Nusselt number, the skin friction coefficient, velocity profile, and temperature profile are presented for different values of the governing parameters for three types of nanoparticles, namely copper, alumina, and titania in the water-based fluid. It is found that the dual solution exists for the decelerating flow. Numerical results show that the extent of the dual solution domain increases with the increases of velocity ratio, magnetic parameter, and permeability parameter whereas it remains constant as the value of solid volume fraction of nanoparticles changes. Also, it is found that permeability parameter has a greater effect on the flow and heat transfer of a nanofluid than the magnetic parameter.

Changing human-environment interactions in medium mountains:the Apuseni Mts(Romania)as a case study

The study of human-environment relationships in mountain areas is important for both theoretical and practical reasons, as many mountain areas suffer similar problems, such as depopulation, unemployment and natural hazards. Medium mountains constitute a special case within mountains, because they are more populated but less attractive as tourist destinations than high mountains. In this context, the Apuseni Mts(Romania) are considered as a case study. In this paper, we apply GIS-based, quantitative methods to characterize the strength and dynamics of human-environment interactions, taking into consideration some environmental factors(elevation, relative height, slope, river distance, lithology, land cover, natural attractions) as well as historical population and recent tourism data. We found that population density has strong(r2>0.8) relationships with all relief factors(elevation, relative height, slope, river distance), and that best-fit functions are nonlinear. We outlined the varying demographic scenarios by elevation zones and interpreted the historically switching sign of population change versus elevation relationship. We demonstrated that lithology also has an impact on the spatial distribution of population, although it is notindependent from the relief effect. The land cover of the mainly cultural landscape is very strongly correlated with relief parameters(especially slope), which suggests good adaptation. We pointed out the dominance of karst objects in the natural tourism potential of the Apuseni Mts and also explored further components of real tourism(spas, heritage, towns). Finally, we concluded that the environmental settings investigated do in fact constrain the spatial framework of society, but socio-economic changes in history can be explained from the side of society, which conforms to the theory of cultural possibilism.

Mixed convection in gravity-driven nano-liquid film containing both nanoparticles and gyrotactic microorganisms

Analysis of a gravity-induced film flow of a fluid containing both nanoparticles and gyrotactic microorganisms along a convectively heated vertical surface is presented.The Buongiorno model is applied. Two kinds of boundary conditions, the passive and the active boundary conditions, are considered to investigate this film flow phenomenon.Through a set of similarity variables, the ordinary differential equations that describe the conservation of the momentum, the thermal energy, the nanoparticles, and the microorganisms are derived and then solved numerically by an efficient finite difference technique.The effects of various physical parameters on the profiles of momentum, thermal energy,nanoparticles, microorganisms, local skin friction, local Nusselt number, local wall mass flux, and local wall motile microorganisms flux are investigated. It is expected that the passively controlled nanofluid model can be much more easily achieved and applied in real circumstances than the actively controlled model.

Natural convection of an alumina-water nanofluid inside an inclined wavy-walled cavity with a non-uniform heating using Tiwari and Das' nanofluid model

The present study is devoted to numerical analysis of natural convective heat transfer and fluid flow of alumina-water nanofluid in an inclined wavy-walled cavity under the effect of non-uniform heating. A single-phase nanofluid model with experimental correlations for the nanofluid viscosity and thermal conductivity has been included in the mathematical model. The considered governing equations formulated in dimensionless stream function, vorticity, and temperature have been solved by the finite difference method. The cavity inclination angle and irregular walls(wavy and undulation numbers)are very good control parameters for the heat transfer and fluid flow. Nowadays, optimal parameters are necessary for the heat transfer enhancement in different practical applications. The effects of the involved parameters on the streamlines and isotherms as well as on the average Nusselt number and nanofluid flow rate have been analyzed. It has been found that the heat transfer rate and fluid flow rate are non-monotonic functions of the cavity inclination angle and undulation number.

Mixed convection boundary layer flow past vertical flat plate in nanofluid: case of prescribed wall heat flux

An analysis is carried out to investigate the steady mixed convection bound- ary layer flow of a water based nanofluid past a vertical semi-infinite flat plate. Using an appropriate similarity transformation, the governing partial differential equations are transformed into the coupled, nonlinear ordinary （similar） differential equations, which are then solved numerically for the Prandtl number Pr = 6.2. The skin friction coeffi- cient, the local Nusselt number, and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction φ and the mixed convection parameter λ on the fluid flow and heat transfer characteristics are thoroughly examined. Different from an assisting flow, it is found that the solutions for an opposing flow are non-unique. In order to establish which solution branch is stable and physically realizable in practice, a stability analysis is performed.

Flow and heat transfer of nanofluid past stretching/shrinking sheet with partial slip boundary conditions

The boundary layer flow of a nanofluid past a stretching/shrinking sheet with hydrodynamic and thermal slip boundary conditions is studied. Numerical solutions to the governing equations are obtained using a shooting method. The results are found for the skin friction coefficient, the local Nusselt number, and the local Sherwood number as well as the velocity, temperature, and concentration profiles for some values of the velocity slip parameter, thermal slip parameter, stretching/shrinking parameter, thermophoresis parameter, and Brownian motion parameter. The results show that the local Nusselt number, which represents the heat transfer rate, is lower for higher values of thermal slip parameter, thermophoresis parameter, and Brownian motion parameter.

Direct and Simultaneous Determination of Several Impurity Elements in Manganese Tetroxide using ICP-AES

A rapid method for the determination of impurity elements, such as Zn, Ni, Co, Cr, Cu, Cd and Pb in manganese tetroxide was developed, using inductively coupled plasma atomic emission spectrometry （ICP-AES）. The critical instrumental parameters such as sample flow rate and radio frequency incident were thoroughly optimized. The effect of matrix was also examined. The sensitivity was investigated using calibration curves obtained in presence of the matrix. The obtained recoveries for Ni, Co, Cr, Cu, and Cd at the μg· g^ -1 level were satisfactory and practically independent of the matrix used for the calibration standards. The recoveries of Pb and Zn were less suffwient. The method can be applied for routine analysis and quality control purposes at μg· g^-1 level of concentration.

Observation of Hydration-Drying Effect on Clotrimazole-Carbopol System

可能性将当为 clotrimazole 的聚合矩阵被分析，使用 polyacrylic 酸(carbopol ) 。聚合矩阵上的弄干水和的效果被拉曼光谱学观察。类似的观察在在聚合矩阵包括的 clotrimazole 上被获得。clotrimazole 并且聚合矩阵的性质的修正都没在水的重复行动下面被观察。

Deactivation of Streptococcus mutans Biofilms on a Tooth Surface Using He Dielectric Barrier Discharge at Atmospheric Pressure

This paper presents a study of the effect of the low temperature atmospheric helium dielectric barrier discharge（DBD） on the Streptococcus mutans biofilms formed on tooth surface. Pig jaws were also treated by plasma to detect if there is any harmful effect on the gingiva.The plasma was characterized by using optical emission spectroscopy.Experimental data indicated that the discharge is very effective in deactivating Streptococcus mutans biofilms.It can destroy them with an average decimal reduction time（D-time） of 19 s and about 98%of thein were killed after a treatment time of 30 s.According to the survival curve kinetic an overall 32 s treatment time would be necessary to perform a complete sterilization.The experimental results presented in this study indicated that the helium dielectric barrier discharge,in plan-parallel electrode configuration,could be a very effective tool for deactivation of oral bacteria and might be a promising technique in various dental clinical applications.

Rheological Behavior of Some Aqueous Gels of Carbopol with Pharmaceutical Applications

The concentration and temperature dependence of the viscosity is observed for some aqueous dispersions of Carbopol. The experimental data are analyzed with the power model, and reveal non-Newtonian behavior （shear thinning） of the samples.

Mixed convection stagnation-point flow on vertical stretching sheet with external magnetic field

The problem of steady laminar magnetohydrodynamic （MHD） mixed con- vection stagnation-point flow of an incompressible viscous fluid over a vertical stretch- ing sheet is studied. The effect of an externally magnetic field is taken into account. The transformed boundary layer equations are solved numerically by using an implicit finite-difference scheme. Numerical results are obtained for various values of the mixed convection parameter, Hartmann number, and Prandtl number. The effects of an exter- nally magnetic field on the skin friction coefficient, local Nusselt number, velocity, and temperature profiles for both A 〉 1 and A ~ 1, where A is the velocity ratio parameter, are presented graphically and discussed in detail. Both assisting and opposing flows are considered, and it is found that dual solutions exist for the opposing flow.

Smad7 dependent expression signature highlights BMP2 and HK2 signaling in HSC transdifferentiation

AIM: To analyse the influence of Smad7, antagonist of transforming growth factor (TGF)-β canonical signaling pathways on hepatic stellate cell (HSC) transdifferentia-tion in detail. METHODS: We systematically analysed genes regulated by TGF-β/Smad7 in activated HSCs by microarray analy-sis and validated the results using real time polymerase chain reaction and Western blotting analysis. RESULTS: We identif ied 100 known and unknown tar-gets underlying the regulation of Smad7 expression and delineated 8 gene ontology groups. Hk2, involved in glycolysis, was one of the most downregulated proteins, while BMP2, activator of the Smad1/5/8 pathway, was extremely upregulated by Smad7. However, BMP2 de-pendent Smad1 activation could be inhibited in vitro by Smad7 overexpression in HSCs. CONCLUSION: We conclude (1) the existence of a tight crosstalk of TGF-β and BMP2 pathways in HSCs and (2) a Smad7 dependently decreased sugar metabolism ameliorates HSC activation probably by energy with-drawal.

Mixed convection heat transfer in horizontal channel filled with nanofluids

The laminar fully developed nanofluid flow and heat transfer in a horizonal channel are investigated. Highly accurate solutions for the temperature and nanopavticle concentration distributions are obtained. The effects of the Brownian motion parameter Nb, the thermophoresis parameter Nt, and the Lewis number Le on the temperature and nanoparticle concentration distributions are discussed. The current analysis shows that the nanoparticles can improve the heat transfer characteristics significantly for this flow problem.

Peri-Gondwanan terranes in the Romanian Carpathians:A review of their spatial distribution,origin,provenance,and evolution

The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri- Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas. The Danubian domain of the South Carpathians comprises the Dragsan and Lainici-Paiius peri-Amazonian terranes. The Dragsan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at -800 Ma. It does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane, The Lainici-Pfiius terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism, It is attached to the Moesia platform. The TisoviD terrane is an ophiolite that marks the boundary between Drfagsan and Lainici-Paius terranes. The other basement terranes of the Romanian Carpathians originated close to the Ordovician North- African orogen, as a result of the eastern Rheic Ocean opening and closure. Except for the Sebes-Lotru terrane that includes a lower metamorphic unit of Cadomian age, all the other terranes （Bretila, Tulghes, Negrisoara and Rebra in the East Carpathians, Somes, Biharia and Baia de Aries in the Apuseni mountains, Fagaras, Leaota, Carat and Pades in the South Carpathians） represent late Cambrian-Ordovician rock assemblages. Their provenance, is probably within paleo-nortbeast Africa, close to the Arabian-Nubian shield. The late Cambrian-Ordovician terranes are defined here as Carpathian-type terranes. According to their lithostratigraphy and origin, some are of continental margin magmatic arc setting, whereas others formed in rift and back-arc environment and closed to passive continental margin settings. In a paleo- geographic reconstruction, the continental margin magmatic arc terranes were first that drifted out, followed by the passive continental margin terranes with the back-arc terranes in their front. They accreted to Laurussia during the Variscan orogeny. Some of them （Sebes-Lotru in South Carpathians and Baia de Aries in Apuseni mountains） underwent eclogite-grade metamorphism. The Danubian terranes, the Bretila terrane and the Somes terrane were intruded by Variscan granitoids.

Analysis of Rheological Behavior of Some Aqueous PEO Gels under Thermal Treatment

一些的粘性的进化水(乙烯氧化物) poly，胶化为受到热吃惊的样品作为聚合集中和温度的功能被观察。试验性的数据被分析跟随一个适当算法，并且揭示短暂效果从对牛顿非牛顿现在作为聚合集中的功能。