Mechanical Characterization of APA Microcapsules by Parallel-Plate Compression

We produced microcapsules of alginate-poly(L)lysine-alginate (APA)with diameters on the order of 10 µm. To characterize their mechanical properties, we conducted an experiment on the parallel-plate compression of a microcapsule and modeled its deformation. In the modeling task, the microcapsule was assumed to be a spherical liquid-filled elastic membrane with negligible bending stiffness and permeability. The membrane thickness was estimated by applying Reissner's linear elastic theory to the experimental force-displacement relationship during loading in the small displacement region. The initial stretch of the membrane was taken into account; it was mainly caused by the osmotic pressure difference across the membrane. The initial stretch of the microcapsule was determined by fitting the calculated and experimental force-displacement relationships during loading at small to medium displacements. At large displacements, the calculated force was smaller than the experimentally measured force because of fluid permeation across the APA membrane. The calculated and experimentally imaged shapes of the deformed microcapsule were compared. The effects of varying the membrane thickness on the force-displacement and transmural pressure-displacement curves were shown, and the limitations of applying the present deformation model were examined

NKX2-1/TTF-1: An Enigmatic Oncogene that Functions as a Double-Edged Sword for Cancer Cell Survival and Progression

Emerging evidence indicates that NKX2-1, a homeobox-containing transcription factor also known as TTF-1, plays a role as a “lineage-survival” oncogene in lung adenocarcinomas. In T cell acute lymphoblastic leukemia, gene rearrangements lead to aberrant expression of NKX2-1/TTF-1. Despite accumulating evidence supporting its oncogenic role, it has become apparent that NKX2-1/TTF-1 expression also has biological and clinical functions in the opposite direction that act against tumor progression. Herein, we review recent findings showing these enigmatic double-edged characteristics, with special attention given to the roles of NKX2-1/TTF-1 in lung development and carcinogenesis

Film Rupture And Partial Wetting Over Flat Surfaces

Various technical applications require conditions which prevent thin liquid films from breaking into a series of rivulets, leaving the solid surface partly uncovered and lowering the extension of the liquid free interface. What is needed is both a criterion for the stability of the film to identify the minimum flow rate able to ensure the complete wetting of the surface and, after the film rupture, a method to estimate the wet (active) part of the same surface. At low Reynolds and high Weber numbers, the assumptions of a film with uniform thickness and complete wetting of the transfer surface cannot be considered, even approximately, rigorous, hence, leading to unacceptable inaccuracy of simulation results of the transfer performance in that operative region. Accordingly, the inadequacy of previous theoretical models of devices that use falling films as transfer mediums can be ascribed to a major issue, namely the assumption of complete wetting. As they provide a simple variational method to solve complex, multi-variable problems and directly reach a rational explanation of physical phenomena, extremum principles have led to critical results in the theoretical and technical fields. Hamilton’s principle (or principle of least action), Gauss’ principle of least constraint, as well as Oasager’s extremum principle or Prigogine’s principle of minimum entropy production remain central in modern physics and engineering. In this context and with regard to the previously stated technical aim, the principle of minimising the energy of a given stream-wise section of the film is applied in order to model and investigate the film stability. Specifically, a criterion for defining the film stability is established for a rivulet cross-section shape suitable for predicting the transient evolution of the wetting ability under an imposed fluid distribution width. The evolution from uniform film to the stable rivulet configuration is estimated considering the energy of the system under a Lagrangian approach. The Lagrange equation is written with reference to a single generalized wetting coordinate and its time derivative, under the effect of Rayleigh\u27s dissipation function and a generalized force associated to a scalar potential defined as the energy excess with respect to the local energy minimum. This methodology is extended to include the hysteresis behaviour of the contact angle (considering advancing and receding contact angles) and wettability hysteresis when increasing or decreasing mass flow rates are delivered. Finally, a first qualitative and quantitative validation of the results is presented with reference to the visual data captured on a dedicated experimental test section

THE IMPROVEMENT OF SKILL BY SNOWBOADING CLASS OF THE UNIVERSITY GENERAL EDUCATION ATHLETICS

本研究はスノーボード集中授業により初心者の滑走スキルがどの程度向上したかを検討したものである｡実技試験を実施した結果､以下の如くの結果が得られた｡即ち､転倒者の割合は女子班では55.6%､男子班では50.0%と約半数が転倒する状態であった｡男子班は全員､連続ターンが出来ていたが女子班 では出来ないかほとんど出来ない者が約4割であった｡平均ターン回数は男子班が9.8回,女子班が2.9回で女子班の値が小さかった(P<0.1)｡その理由については､男女の体力差や指導方法の違いなどが考えられる｡試技の平均所要時間は男子班が33.0秒で女子班が41.0秒であった｡経験者班を基準にする と男子班は12.6%,女子班は40.0%余分に時間を要している状態であった｡事前のスケートボード練習の有効性は確認できなかった｡理由としては､練習の回数と時間が少な過ぎたことと参加者数が少なかったことによると推察される｡This study is a report on the run skill of beginners of snowboarding intensive class. The skill test brought the following results.A ratio of the students who fell down at this test was 55.6% in the female group, and was 50.0% in the male group. All of the male group could do turns of the right and left alternation. However, about 40% of the female group could not do such turn at all or could not do without great difficulty. The average of the turn of the group of male was 9.8 times, and it of the group of female was 2.9 times. The numerical value of the female group was small (p<0.1). As a reason, it seems that the difference of physical resources between male and female. And next, it seems that the reason is in a variety of teaching methods of each coach. The group of the male needed time of 33.0 seconds on average for run and it of the group of female was 41.0 seconds. In comparison with the group of the experienced students, the male group spent time more 12.6%, and the surplus time of female group is 40.0%. The effectiveness of the skateboarding exercise before the class was not confirmed. As reasons it seemed that too few times of practice and too few students who belong to group of training were guessed

Influence of the Fluid Distribution Width on the Wettability of Rivulet Flow over Vertical Flat Surfaces

The performance of heat transfer in the processes of evaporation, absorption, distillation and even condensation is affected from the wetting behavior of the liquid film flow on the surface. The complete wetting of the surface is usually required while breaking of thin liquid film is to be avoided. Various experimental settings have been designed by several researchers to investigate the main parameters influencing the stability of the film. However, in order to generalize and properly scale the results, the appropriate dimension of the test section and its influences on the wetting behavior are still unresolved questions that need to be addressed. Three different fluid distribution widths, including 200, 100 and 33 mm, when the geometry of distribution hole, the distance between holes and vertical flat surface are fixed, are carried out. Pure water at ambient temperature is used as working fluid. The measurement is focused on the wettability hysteresis and the shape transition from film to rivulet when the water flow rate are increased or decreased for wetting and dewetting experiments. Visual data captured on the test section under various fluid distribution widths are collected and analyzed using image binarization method to quantify the wetted area. The relation between the wetted area with respect to film Reynolds number and Weber number respectively are presented. The results show that the fluid distribution width can influence the wetting ability. The amount of wetted area, which is used to identify the wetting ability, is quite stable for decreasing flow rates, thus delineating the hysteresis characteristics of the wetting behavior of this solid-liquid pair. In general, a longer distributor width seems to be associated to a lower wetting ability and a lower wetting hysteresis. However, the same observation could not be applied to the results extracted with a 33mm width