Spatial Patterns of Microbial Retention on Polymer Surfaces

Microbial adhesion and retention on surfaces are complex phenomena, critical to the formation and development of biofilms. Recently, the focus of research has been more and more on the importance of retention of bacteria under fluctuating high shear forces in biofilm formation. The aim of the present work was to carry out a comparative study of the retention process of different bacterial and yeast species using: (1) a range of surfaces with different surface free energy properties and (2) a number of different bacterial cell physiological states. It was found for the first time that once a threshold cell number is retained on the surface, microbial retention patterns are formed following a power law, i.e., not stochastic. Our results demonstrated that the overall spatial patterns of microbial retention observed for the different substrates are similar for the all investigated cell types and that the drastic modification of the surface free energy does not affect this spatial organization. On the other hand, the microbial retention patterns appear to be significantly affected by the physiological state of the cells. Finally, the experimental retention patterns have been well simulated by a general agent-based model, confirming that the typical fractal distribution of retained cells is the result of a self-organization process.     

水冷壁气化炉熔渣表面形态的几何特性

在小型气流床气化炉中进行了水冷壁结渣实验，研究了不同温度下炉内熔渣的表面形态，并进行了定量分析。本文提出了当量温度T的概念，T等于熔渣温度与灰熔点的比值。利用图像分析软件ImageJ测得熔渣表面粗糙度，当量温度小于1时，粗糙度较高；当量温度大于1时，粗糙度较低。用“小岛法”求得了熔渣表面的分形维数，并得到了当量温度与分维数之间的关系。     

Sound Waves Promote Arabidopsis thaliana Root Growth by Regulating Root Phytohormone Content

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.     

Effect of sound on the fluidization of group B particles

The behaviour of several kinds of group B particles ranging from 100 μm to 600 μm was studied in a sound wave vibrated fluidized bed (SVFB). The fluidized bed consists of a transparent Plexiglas tube that is 54 mm i.d. × 1 m high. A speaker mounted at the top of the bed was supplied by a function generator with square waves and was used to generate the sound as the source of vibration of the fluidized bed. The influence of the particle size, density of particles and sphericity of particles on the minimum fluidization velocity, pressure fluctuations and bubble rise velocity in the SVFB was investigated. The minimum fluidization velocity decreased as the sound energy increased. When the sound energy was strong enough and greater than the critical power, the minimum fluidization velocity would approach the same value regardless of the degree of resonance (DOR) value if the particles were in spherical shape. For non-spherical shape particles the minimum fluidization velocity was the function of the DOR value if the power was greater than the critical power. For the middle particle size range, the standard deviation of pressure fluctuations in an SVFB became lower than the one without the effect of sound in high superficial gas velocity range, but the result was reverse for the low superficial velocity; for the large particle size range, the standard deviation of pressure fluctuations in an SVFB was larger than the one without the effect of sound. The sound could also reduce the bubble rise velocity in an SVFB.     

A study on the potentiostatic current transient and linear sweep voltammogram simulated from fractal intercalation electrode: diffusion coupled with interfacial charge transfer

Potentiostatic current transient and linear sweep voltammogram, theoretically calculated from the well-defined fractal profiles were analysed, with particular emphasis on hydrogen transport under the condition where hydrogen diffusion in the electrode is kinetically coupled with the charge-transfer reaction at the electrode/electrolyte interface. Under such a constraint of mixed control, the simulated current transient from the fractal electrode hardly exhibited the generalised Cottrell behaviour, and, especially, it displayed an inflexion point at the time that corresponds to the temporal outer cut-off of fractality (crossover time required for the fractal to flat transition). In the case of the linear sweep voltammogram computed from the fractal electrode, moreover, the power dependence of the peak current on the scan rate deviated negatively from the generalised Randles-Sev?ik behaviour, above the slow threshold scan rate (crossover scan rate needed for the fractal to flat transition). From the analyses of the current transients and the linear sweep voltammograms calculated with various values of the simulation parameters, it was further recognised that during the potential jump as well as the potential scan, the temporal cut-off ranges of fractality under the constraint of mixed control are crucially determined by the interfacial charge-transfer kinetics, even though the spatial cut-off range and the hydrogen diffusivity in the electrode are maintained constant.     

高分子溶液的水声衰减性能

本文研究了高分子溶液的水声衰减性能 ,发现水声在溶液中的衰减效果随溶液浓度的增加而有规律地增加 ;水声在传播过程中 ,溶液特性可用 Maxwell模型加以描述 ;水声衰减因子α与溶液浓度 c呈线性关系 ,该直线的斜率大于零且与水声的频率有关     

Enhanced sound insulation properties of microporous PMMA foams by constructing novel multilayered and directional cell structure (MDCS)

The main purpose of this study is to improve the performance of soundproofing materials through structure design without any functional phases. The sound insulation properties of PMMA microporous foams with multilayered and directional cell structure (MDCS) were investigated. The influence of the MDCS on sound transmission loss was discussed in detail. In addition, the mechanism for improving the sound transmission loss of the multilayered foams was discussed. The results show that the sound transmission loss value of the multilayered foams is up to 29.70 dB, which is 29.5% higher than that of the single-layer foams. It is due to the MDCS, which reduces the cell size of the foams, leading to increase the reflection and scattering of sound waves in pores. Meanwhile, the MDCS accompanied by multilayer interfaces increases the multiple reflection of sound waves at the interfaces. Besides, the smaller cell size and higher cell density strengthen the stiffness of the foams, which promotes the sound insulation properties. This study presents a novel and convenient method to design modern sound insulation materials.     

基于连续和脉冲超声波对SiC颗粒粒度表征的对比

为了研究连续和脉冲超声波2种不同激励方式对颗粒粒度表征的影响,设计了2套分别基于连续和脉冲超声波对颗粒粒度表征的实验系统,在相同实验条件下,利用一对水浸式探头构成一发一收的模式,采用变声程法,对4种不同浓度的SiC悬浊液声衰减谱进行测量. 结果表明,2套系统所测的声衰减谱趋势相同,连续波激励下的声衰减谱数值偏大10%左右. 结合反演算法得出了SiC微粉颗粒的粒度分布,发现不同激励方式下的颗粒粒度分布吻合程度较好,偏差均在5%以内,说明不同激励方式对颗粒粒度表征最终结果影响不大.     

A study on lithium transport through fractal Li1−δCoO2 film electrode by analysis of current transient based upon fractal theory

Lithium transport through fractal Li_1−δCoO₂ film electrode was investigated in a 1 M lithium perchlorate (LiClO₄)-propylene carbonate (PC) solution by analysis of current transient based upon fractal theory. For this purpose, two kinds of Li_1−δCoO₂ films were deposited by rf magnetron sputtering method on the substrates with different roughnesses. From the analysis of AFM image by the triangulation method, it was found that two Li_1−δCoO₂ film electrodes have the self-similar scaling properties with different spatial outer cut-off ranges. From the analysis of the potentiostatic current transient, it was recognised that the cell-impedance-controlled constraint at the electrode surface is changed to the real potentiostatic boundary condition (diffusion-controlled constraint) when the applied potential step exceeds a critical value and simultaneously the internal cell resistance is below a certain value in the region of single-β-phase. In addition, from the comparison between the cathodic current transients obtained from two fractal Li_1−δCoO₂ film electrodes, it was experimentally confirmed that the current transient shows the generalised Cottrell behaviour before the temporal outer cut-off of fractality, followed by a linear relationship with the slope of −0.5 after the temporal outer cut-off of fractality, when the real potentiostatic boundary condition is maintained at the electrode surface.     

Effect of pore structure on anomalous behaviour of the lithium intercalation into porous V2O5 film electrode using fractal geometry concept

The effect of pore structure on anomalous behaviour of the lithium intercalation into porous V₂O₅ film electrode has been investigated in terms of fractal geometry by employing ac-impedance spectroscopy combined with N₂ gas adsorption method and atomic force microscopy (AFM). For this purpose, porous V₂O₅ film electrodes with different pore structures were prepared by the polymer surfactant templating method. From the analysis of N₂ gas adsorption isotherms and the triangulation analysis of AFM images, it was found that porous V₂O₅ surfaces exhibited self-similar scaling properties with different fractal dimensions depending upon amount of the polymer surfactant in solution and the spatial cut-off ranges. All the ac-impedance spectra measured on porous V₂O₅ film electrodes showed the non-ideal behaviour of the charge-transfer reaction and the diffusion reaction, which resulted from the interfacial capacitance dispersion and the frequency dispersion of the diffusion impedance, respectively. From the comparison between the surface fractal dimensions by using N₂ gas adsorption method and AFM, and the analysis of ac-impedance spectra by employing a constant phase element (CPE), it is experimentally confirmed that the lithium intercalation into porous V₂O₅ film electrode is crucially influenced by the pore surface irregularity and the film surface irregularity.     

超声波化学沉积Co-Ni-B-Ce合金薄膜工艺的研究

研究了超声波条件下工艺参数对Co—Ni—B—Ce合金化学沉积速度的影响，讨论了温度、声强、超声波频率、镀液组成等对沉积速度的影响。研究发现：温度、超声波频率、镀液组成对沉积速度有较大的影响。超声波使Co—Ni—B—Ce化学沉积速度提高30％，在超声条件下，镀液的稳定性降低。随着声强的增加，镀液容易发生自分解，沉积速度迅速减小。通过对工艺的分析，得出了Co—Ni—B—Ce合金超声波化学沉积的最佳工艺参数。     

Lipidomic Analyses of Female Mice Lacking Hepatic Lipase and Endothelial Lipase Indicate Selective Modulation of Plasma Lipid Species

Hepatic lipase (HL) and endothelial lipase (EL) share overlapping and complementary roles in lipoprotein metabolism. The deletion of HL and EL alleles in mice raises plasma total cholesterol and phospholipid concentrations. However, the influence of HL and EL in vivo on individual molecular species from each class of lipid is not known. We hypothesized that the loss of HL, EL, or both in vivo may affect select molecular species from each class of lipids. To test this hypothesis, we performed lipidomic analyses on plasma and livers from fasted female wild-type, HL-knockout, EL-knockout, and HL/EL-double knockout mice. Overall, the loss of HL, EL, or both resulted in minimal changes to hepatic lipids; however, select species of CE were surprisingly reduced in the livers of mice only lacking EL. The loss of HL, EL, or both reduced the plasma concentrations for select molecular species of triacylglycerol, diacylglycerol, and free fatty acid. On the other hand, the loss of HL, EL, or both raised the plasma concentrations for select molecular species of phosphatidylcholine, cholesteryl ester, diacylglycerol, sphingomyelin, ceramide, plasmanylcholine, and plasmenylcholine. The increased plasma concentration of select ether phospholipids was evident in the absence of EL, thus suggesting that EL might exhibit a phospholipase A₂ activity. Using recombinant EL, we showed that it could hydrolyse the artificial phospholipase A₂ substrate 4-nitro-3-(octanoyloxy)benzoic acid. In summary, our study shows for the first time the influence of HL and EL on individual molecular species of several classes of lipids in vivo using lipidomic methods.     

Wellenausbreitung in verfahrenstechnischen Prozessen

Wave propagation phenomena in chemical engineering processes. A phenomenological analysis of the dynamics of a number of different distributed parameter systems in chemical engineering reveals a surprisingly simple dynamic behaviour despite the complexity of the underlying nonlinear process models. Spatial structures or waves are propagating along a spatial coordinate during transients. The dynamics of most of the processes under consideration can be described with sufficient accuracy by three different model structures. These models serve as a basis for a theoretical system analysis. The investigation of characteristic properties of the propagating waves and the mechanisms responsible for wave formation are of central significance. Finally, it is shown how the extended knowledge about the processes may be applied for the solution of problems of technical interest.     

Volumetric properties at high pressure of waste oil methyl ester compared with diesel oil

In this paper, the isothermal compressibility coefficient, the cubic expansion coefficient and the propagation speed of pressure waves of waste oil methyl ester (WOME) and diesel oil (DO) are presented. These properties can be derived mathematically from the specific volume, the only property measured in this work (from 288.15 to 328.15 K and from atmospheric pressure to 350 MPa). The modified Tait–Tammann Equation has been adjusted to the experimental data with a high correlation coefficient and confidence level. Because of their different physical properties, the use of WOME instead of DO can affect the behaviour of some diesel equipments and, for instance, the economic efficiency and the behaviour of heat engines.     

Structural correspondence between music and color

The article outlines the features that are typical of the attempts to bridge between music and color on the artistic and scientific levels. It emphasizes the importance of clarifying the factors common to color and sound both for the purpose of understanding the communication codes of arts as well as for the development of syntax for expression in colors. The article adopts Gombreich's approach to investigate the connection between music and color through comparison of the relationships between the elements and not through comparison of the elements themselves. The article presents an experiment that examines how the organization of the sounds in a musical piece is expressed in color design: (1) How the overall impression of a piece of music is expressed in the choice of colors and in their reciprocal relationships; (2) What are the characteristics of color scales that were shaped according to a musical scale; and (3) What is the visual effect of a color scheme that was built according to the formation of notes of the musical piece.     

Oscillatory behaviour of the reduction of NO by H2 over Rh

The NO reduction by H₂ on Rh has been studied by field emission microscopy (FEM). It has been observed that this reduction shows oscillatory behaviour at 460 K andP _NO = –1.5 ×10^–1 Torr andP _H2 =1×10^-6 Torr, Unique features of FEM are the very high spatial resolution and the presence of, in principle, an indefinite number of different crystal planes. The oscillatory behaviour is reflected by periodic changes in the emission current and in the images observed. The communication between different surfaces present on the field emitter is shown on a fluorescent screen. Diffusion and gas phase coupling seem to play a role. Many of the features reported earlier for the oscillatory behaviour of the NO-H₂ and NO-NH₃ reactions over Pt(100) are observed on Rh as well, including the surface explosion. The vacancy model proposed earlier for the oscillations over Pt(100), can be applied to the reactions described in this paper as well.     

Amberlite XAD‐2 Impregnated with Cyanex302 for Separation of Traces of Thorium(IV)

Abstract

Amberlite XAD‐2 resin impregnated with Cyanex302 has been used to separate and preconcentrate thorium(IV) from associated elements prior to its spectrophotometric determination. The impregnated resin (HL‐XAD‐2) was characterized by IR spectra. A column packed with HL‐XAD‐2 was used to understand sorption and desorption behaviour of thorium(IV). The effect of various parameters such as acidity of aqueous phase, nature and concentration of eluting agents, eluent volume and its flow rate were evaluated to optimize conditions for isolation of thorium(IV). Adsorption characteristics of thorium(IV) on HL‐XAD‐2 in batch studies indicated that the data fit well in Langmuir and Freundlich adsorption isotherm models. The maximum sorption capacity of the modified resin for thorium(IV) was 8.48 mmol g^?1 while the limit of detection (3σ_B) was 0.75 µg dm^?3. A preconcentration factor greater than 100 was achieved. The influence of diverse ions on extraction of thorium(IV) was examined and the method developed was applied for the separation of thorium(IV) from synthetic mixtures and monazite sand. The method is reproducible with a relative standard deviation (R.S.D.) of 0.6%.