A correlation for drop size and slip velocity in reciprocating plate column

Drop size distributions, mean drop diameter and slip velocity are experimentally studied in a reciprocating plate column. The correlations for the above are presented in terms of plate geometry, flow rates of phases and physical properties of the system covering a wide range in experimental conditions.     

Gas holdup-slip velocity relationship in multistage bubble column

Gas holdup data in multistage bubble column is analyzed through slip velocity incorporating pseudo hydrostatic effect, momentum transfer effect, particle-to-particle and particle-to-wall effects and coalescence effects. The bubble size, required for the estimation of single bubble rise velocity, is satisfactorily predicted using the model due to Molerus [9], and the influence of gas throughput, the perforation diameter and the free area of the horizontal plate, as well as the plate spacing on bubble size are examined.     

Hydrodynamic and Thermal Slip Effect on Double-Diffusive Free Convective Boundary Layer Flow of a Nanofluid Past a Flat Vertical Plate in the Moving Free Stream

The effects of hydrodynamic and thermal slip boundary conditions on the double-diffusive free convective flow of a nanofluid along a semi-infinite flat solid vertical plate are investigated numerically. It is assumed that free stream is moving. The governing boundary layer equations are non-dimensionalized and transformed into a system of nonlinear, coupled similarity equations. The effects of the controlling parameters on the dimensionless velocity, temperature, solute and nanofluid concentration as well as on the reduced Nusselt number, reduced Sherwood number and the reduced nanoparticle Sherwood number are investigated and presented graphically. To the best of our knowledge, the effects of hydrodynamic and thermal slip boundary conditions have not been investigated yet. It is found that the reduced local Nusselt, local solute and the local nanofluid Sherwood numbers increase with hydrodynamic slip and decrease with thermal slip parameters.     

Heat Transfer Analysis for Stationary Boundary Layer Slip Flow of a Power-Law Fluid in a Darcy Porous Medium with Plate Suction/Injection

In this paper, we investigate the slip effects on the boundary layer flow and heat transfer characteristics of a power-law fluid past a porous flat plate embedded in the Darcy type porous medium. The nonlinear coupled system of partial differential equations governing the flow and heat transfer of a power-law fluid is transformed into a system of nonlinear coupled ordinary differential equations by applying a suitable similarity transformation. The resulting system of ordinary differential equations is solved numerically using Matlab bvp4c solver. Numerical results are presented in the form of graphs and the effects of the power-law index, velocity and thermal slip parameters, permeability parameter, suction/injection parameter on the velocity and temperature profiles are examined.     

Effect of nanostructure on heat transfer between fluid and copper plate: a molecular dynamics simulation study

A molecular simulation is developed to study the effect of surface nanostructures on nanoscale flows. Based on this method, particles equation of motion is solved through the Verlet algorithm. Meanwhile, a physically sound method is applied to control the momentum and temperature of the simulation box. By adding an external force on the top copper plate according to the velocity difference between on-the-fly and desired velocities, simulations on convection of argon flows between two solid walls are performed. The top wall, which holds a higher temperature, moves at a constant velocity relative to bottom one along with the streamwise direction. These simulation results show that the nanostructures particularly affect fluid density oscillations adjacent to solid wall and nanostructures. In addition, these nanostructures also have significant effects on temperature and velocity distributions in simulation system.     

High lipid order of Arabidopsis cell‐plate membranes mediated by sterol and DYNAMIN‐RELATED PROTEIN1A function

Membranes of eukaryotic cells contain high lipid‐order sterol‐rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher‐plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell‐plate formation in Arabidopsis relies on sterol‐ and DYNAMIN‐RELATED PROTEIN1A (DRP1A)‐dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order‐sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid‐order membrane domain. The cell‐plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co‐localize with DRP1A at the cell plate, and DRP1A accumulates in detergent‐resistant membrane fractions. Modifications of sterol concentration or composition reduce cell‐plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid‐order domain, and pave the way to explore potential feedback between lipid order and function of dynamin‐related proteins during cytokinesis.     

Xylanase mass transfer studies in aqueous two-phase systems using spray and sieve plate columns

Aqueous two-phase systems (ATPSs) have long been used for biomolecule partitioning; these systems offer the possibility of using continuous or semicontinuous extraction processes. They require relatively simple equipment like spray or sieve plate columns that can be adapted for use in ATPSs. The aim of this work was to study the semicontinuous extraction of a model enzyme, xylanase, in spray and sieve plate columns, since, unlike centrifugal contactors, the cost of construction and maintenance of this equipment is low and it is easy to operate. For the spray column, the dispersed phase hold-up and overall mass transfer coefficients K(D) a were evaluated for different column heights and for different superficial velocities of the dispersed phase (light phase). Results indicated that an increase in superficial velocity in the range of 0-0.18 mm/s of the dispersed phase had a positive effect on K(D) a and on hold-up in all column heights studied, 75, 161 and 246 mm. For the same superficial velocity of the dispersed phase, the larger the hold-up was, the shorter the column. For the sieve plate column, the effects of the superficial velocity of the dispersed phase and the number of plates were also studied. Results showed that the K(D) a and hold-up increased with an increase in both parameters. The selectivity of separation of xylanase and BSA (model contaminant) was very high, since 60% of the enzyme was extracted in the light phase, whereas no significant amount of BSA was extracted. The possibility of using the sieve plate column in continuous operation for enzyme extraction was studied because previous work had only addressed the semicontinuous extraction of enzyme. The residence time distribution of the PEG phase using different superficial velocities of the salt phase was studied in continuous operation. The time required to reach the steady state was 40 min, and 70% of the xylanase was recovered. It was found that the Modified Power Spline software was well adjusted to the experimental results.     

Autoradiography of Water-Soluble Materials in Plant Tissues

Samples of tissue with water-soluble substances are lyophilized and doubly-infiltrated with parlodion and paraffin. Sections are mounted on an adhesive-coated cover slip with chloroform. The reverse side of the cover slip is coated successively with a thin layer of Harleco resin and a thick layer of Kodak “Opaque”. A corner of the cover slip is broken off as a marker. The cover slip is assembled with a covering glass slide on a nuclear track plate (Kodak NTB-2) with protective coating, the section being in contact with the emulsion, and held in place during radioactive exposure. Before development, the cover slip and plate are exposed briefly to light and then disassembled. Following development of the plate and removal of the layer of resin and opaque from the cover slip, staining of the section is optional. Lining up of the section with its autoradiograph can be accurate within 1-5μ.     

Double Diffusive Magnetohydrodynamic (MHD) Mixed Convective Slip Flow along a Radiating Moving Vertical Flat Plate with Convective Boundary Condition

In this study combined heat and mass transfer by mixed convective flow along a moving vertical flat plate with hydrodynamic slip and thermal convective boundary condition is investigated. Using similarity variables, the governing nonlinear partial differential equations are converted into a system of coupled nonlinear ordinary differential equations. The transformed equations are then solved using a semi-numerical/analytical method called the differential transform method and results are compared with numerical results. Close agreement is found between the present method and the numerical method. Effects of the controlling parameters, including convective heat transfer, magnetic field, buoyancy ratio, hydrodynamic slip, mixed convective, Prandtl number and Schmidt number are investigated on the dimensionless velocity, temperature and concentration profiles. In addition effects of different parameters on the skin friction factor, , local Nusselt number, , and local Sherwood number are shown and explained through tables.     

Interfacial Friction and Collective Diffusion in Nanopores

A simple Brownian model for the collective dynamics of a fluid confined by rigid walls is described for which the collective velocity autocorrelation function (CVACF) decays exponentially. Using this approach, a new method of calculating the Maxwell velocity slip coefficients from the collective diffusion coefficient, obtained from equilibrium molecular dynamics, is proposed. A comparison of the slip coefficients for a range of fluid densities with the results obtained from the tangential velocity loss of the colliding particles in non-equilibrium simulations show excellent agreement.     

Autoradiography of Water-Soluble Materials in Plant Tissues

Samples of tissue with water-soluble substances are lyophilized and doubly-infiltrated with parlodion and paraffin. Sections are mounted on an adhesive-coated cover slip with chloroform. The reverse side of the cover slip is coated successively with a thin layer of Harleco resin and a thick layer of Kodak “Opaque”. A corner of the cover slip is broken off as a marker. The cover slip is assembled with a covering glass slide on a nuclear track plate (Kodak NTB-2) with protective coating, the section being in contact with the emulsion, and held in place during radioactive exposure. Before development, the cover slip and plate are exposed briefly to light and then disassembled. Following development of the plate and removal of the layer of resin and opaque from the cover slip, staining of the section is optional. Lining up of the section with its autoradiograph can be accurate within 1-5μ.     

Interactions between heterotrophic plate count bacteria and coliform organisms

Studies were initiated to investigate the interactions between heterotrophic plate count bacteria and coliform organisms. We used spiked samples to show that heterotrophic plate count bacteria could reduce coliform densities by more than 3 logs within 8 days. Some heterotrophic plate count bacteria were able to cause injury to the coliform population. A significant correlation (r = 0.66; P less than 0.05) was observed between the initial level of heterotrophic plate count bacteria and the rate of coliform decline. Competition for limiting organic carbon was hypothesized to be responsible for the observed effects.     

Interactions between heterotrophic plate count bacteria and coliform organisms.

Studies were initiated to investigate the interactions between heterotrophic plate count bacteria and coliform organisms. We used spiked samples to show that heterotrophic plate count bacteria could reduce coliform densities by more than 3 logs within 8 days. Some heterotrophic plate count bacteria were able to cause injury to the coliform population. A significant correlation (r = 0.66; P less than 0.05) was observed between the initial level of heterotrophic plate count bacteria and the rate of coliform decline. Competition for limiting organic carbon was hypothesized to be responsible for the observed effects.     

锁定钢板与解剖钢板内固定在pilon骨折治疗中的应用比较

目的探讨锁定钢板与解剖钢板内固定在pilon骨折治疗中的应用效果。方法选取我院收治的pilon骨折患者91例为研究对象,根据治疗方式不同分为对照组45例和观察组46例。对照组予以解剖钢板内固定治疗,观察组患者采用锁定钢板内固定治疗,并对两组患者的治疗效果进行比较分析。结果观察组患者的手术时间、骨折愈合时间、住院时间、下地负重时间均明显短于对照组,差异具有显著统计学意义(P0.05)。观察组的优良率为91.1%,对照组的优良率为64.4%,两组比较差异有统计学意义(P0.05)。两组患者治疗前各项生活质量评分无明显差异(P0.05);治疗后,观察组的生理功能、身体疼痛、总体健康、活力、情感职能、心理健康评分均明显优于对照组(P0.05)。结论锁定钢板内固定在pilon骨折治疗中的应用效果优于解剖钢板内固定,值得临床推广应用。     

The effects of slip velocity at a membrane surface on blood flow in the microcirculation

Closed-form solutions are presented for blood flow in the microcirculation by taking into account the influence of slip velocity at the membrane surface. In this study, the convective inertia force is neglected in comparison with that of blood viscosity on the basis of the smallness of the Reynolds number of the flow in microcirculation. The permeability property of the blood vessel is based on the well known Starling's hypothesis [11]. The effects of slip coefficient on the velocity and pressure fields are clearly depicted.     

Cartilage formation in growth plate and arteries: from physiology to pathology

Vascular calcifications are the consequence of several pathological conditions such as atherosclerosis, diabetes, hypercholesterolemia and chronic renal insufficiency. They are associated with risks of amputation, ischemic heart disease, stroke and increased mortality. A growing body of evidence indicates that vascular smooth muscle cells (VSMCs) undergo chondrogenic commitment eventually leading to vascular calcification, by mechanisms similar to those governing ossification in the cartilage growth plate. Our knowledge of the formation of cartilage growth plate can therefore help us to understand why and how arteries calcify and, consequently, develop new therapeutic strategies. Reciprocally, thorough consideration of the events leading to ectopic chondrocyte differentiation appears crucial to further increase our understanding of growth plate formation. In this context, we will review the effects of known or suspected factors that promote chondrogenic differentiation in growth plate and arteries.     

Endocrine regulation of the growth plate

Longitudinal bone growth occurs at the growth plate by endochondral ossification. Within the growth plate, chondrocyte proliferation, hypertrophy, and cartilage matrix secretion result in chondrogenesis. The newly formed cartilage is invaded by blood vessels and bone cells that remodel the newly formed cartilage into bone tissue. This process of longitudinal bone growth is governed by a complex network of endocrine signals, including growth hormone, insulin-like growth factor I, glucocorticoid, thyroid hormone, estrogen, androgen, vitamin D, and leptin. Many of these signals regulate growth plate function, both by acting locally on growth plate chondrocytes and also indirectly by modulating other endocrine signals in the network. Some of the local effects of hormones are mediated by changes in paracrine factors that control chondrocyte proliferation and differentiation. Many human skeletal growth disorders are caused by abnormalities in the endocrine regulation of the growth plate. This review provides an overview of the endocrine signals that regulate longitudinal bone growth, their interactions, and the mechanisms by which they affect growth plate chondrogenesis.     

Hormonal regulation of growth plate cartilage

Longitudinal bone growth occurs in the growth plate through a process called endochondral bone formation, a process where resting zone chondrocytes are recruited to start active proliferation and then undergo differentiation, followed by apoptosis and later mineralization. The balance between proliferation and differentiation is a crucial regulatory step controlled by various growth factors/hormones acting in both endocrine and paracrine/autocrine ways. From studies of individuals with aromatase deficiency and a boy with defective oestrogen receptor (ER)-alpha it has become clear that oestrogen action is indispensable for normal pubertal growth and growth plate fusion. Both oestrogen receptors, ER-alpha and ER-beta, are expressed in the growth plate in boys and girls throughout pubertal development. Any functional role of ER-beta has not yet been defined in the human growth plate. Increased understanding about the effects of oestrogen and the interactions between oestrogens and other endocrine factors within the growth plate is important for the development of new treatment strategies in different disorders affecting longitudinal bone growth. As new specific modulators of oestrogen receptors are developed, these could offer more specific ways to modulate longitudinal growth and growth plate fusion.     

Water Flow Through Vessel Perforation Plates--The Effects of Plate Angle and Thickness for Liriodendron tulipifera

The effects of scalariform perforation plate thickness and anglewithin vessel elements of Liriodendron tulipifera were studiedwith a computational fluid dynamical model. The pressure gradientand hence resistance to flow through the plate increased asthe perforation plate increased in thickness. Increasing theangle of the plate relative to the axis of the vessel (samenumber of pores) also increased the pressure gradient alongthe modelled cell. For the model matching the actual vesselelement, the plate contributed 8% to the flow resistance ofthe vessel element. This contribution increased only to 11%for doubled plate thickness, and to 14% for a plate at an angleof 60° to the vessel axis. The perforation plate alteredthe velocity profile across the vessel element, but to a differentextent depending on the angle of the plate. A plate at an acuteangle to the vessel axis has little effect on the paraboloidprofile as found upstream from the plate, while obtuse angleplates change the flow profile such that fluid through poresnear the wall is accelerated to a greater velocity than foundin the centre of the cell. Key words: Conductance, perforation plate, vessel, water flow     

The micropylar plate of the eggs of Phasmida, with a survey of the range of plate form within the order

Eggs of Phasmida are characterized by the presence of a micropylar plate system. The nature of this plate is discussed and the relevance of differences in plate structure to the taxonomy of the order is considered. A survey is made of the range of plate structure throughout the order, covering the external plate structure of 384 species and the internal plate structure of 179 species in forty of the forty-four subgroups of the order.