Multicellular structures in thin free liquid films induced by thermocapillary effect.

HYPOTHESIS: Multicellular convective structures that are induced in a fluid exposed to temperature difference are commonly observed in nature and in daily life. Different types of basic flow patterns are induced in a free liquid film by thermocapillary effect, whereas the formation of such multicellular structures has not been hitherto unravelled. EXPERIMENTS: A thin film of high-Prandtl-number liquid is prepared in a rectangular aperture of the order of 0.1 mm in thickness sustained by its surface tension. A designated temperature difference is imposed between the end surfaces of the aperture to generate a thermocapillary-driven convection in the free liquid film. We monitor the induced thermal flow patterns to evaluate the cell numbers and their wavelength by experimental and numerical approaches. FINDINGS: The multicellular structure is established by the thermocapillary effect in the free liquid films. The cell number increases in a stepwise manner as the liquid-film width increases. When the cell number increases, another pair of the cells always newly emerges. We determine the wavelength in a non-dimensional manner, and present the variation of the wavelength against the aspect ratio corresponding to the liquid-film width. The results are compared to those of convectional Marangoni-Bénard convection.

Enhancement of Meniscus Pump by Multiple Particles.

We numerically investigate the behavior of a droplet spreading on a smooth substrate with multiple obstacles. As experimental works have indicated, the macroscopic contact line or the three-phase boundary line of a droplet exhibits significant deformation resulting in a local acceleration by successive interactions with an array of tiny obstacles settled on the substrate (Mu et al., Langmuir 2019, 35). We focus on the menisci formation and the resultant pressure and velocity fields inside a liquid film in a two-spherical-particle system to realize an optimal design for the effective liquid-transport phenomenon. Special attention is paid to the meniscus formation around the second particle, which influences the liquid supply related to the pressure difference around the first particle as a function of the distance between the two particles. We find that the meniscus around the first particle plays an additional role as the reservoir of the liquid supplied toward the second particle, which is found to enhance the total pumping effect.

Pumping effect of heterogeneous meniscus formed around spherical particle.

HYPOTHESIS: A disturbance such as a microparticle on the pathway of a spreading droplet has shown the tremendous ability to accelerate locally the motion of the macroscopic contact line (Mu et al., 2017). Although this ability has been linked to the particle-liquid interaction, the physical mechanisms behind it are still poorly understood despite its academic interest and the scope of numerous industrial applications in need of fast wetting. EXPERIMENTS: In order to better understand the mechanisms behind the particle-liquid interaction, we numerically investigate the pressure and velocity fields in the liquid film. The results are compared to experiments assessing the temporal shape variation of the liquid-film meniscus from which pressure difference around the particle is evaluated. FINDINGS: The particle-induced acceleration of the film front depends both on the shape of the meniscus that forms around the particle foot and the liquid "reservoir" in the film that can be pumped thanks to the presence of the particle. The study validates the presence of three stages of pressure difference between the upstream and downstream regions of the meniscus around the particle, which leads to the local acceleration/deceleration of the macroscopic contact line. We indicate that asymmetric meniscus around the particle foot produces a net pressure force driving liquid and accelerating the liquid-film front.

Quick Liquid Propagation on a Linear Array of Micropillars.

The wetting process of a high energy surface can be accelerated locally through the capillary interaction of a liquid advancing front with a micro-object introduced to the surface (Mu et al., J. Fluid Mech, 2017, 830, R1). We demonstrate that a linear array of micropillars embedded in a fully wettable substrate can produce quick propagation of liquid along the array. It is observed that multiple interactions of a liquid front with pillars can induce the motion of liquid a hundred times faster than in the absence of pillars.

Flow Patterns Induced by the Thermocapillary Effect and Resultant Structures of Suspended Particles in a Hanging Droplet.

We focus on the flow patterns and resultant structures of suspended solid particles in a hanging droplet caused by the thermocapillary effect. A droplet is hung on a heated cylindrical rod facing downward, and another cooled rod is placed just beneath the droplet to create the temperature difference between both ends of the droplet. As the temperature difference increases, the induced flow exhibits transitions from an axisymmetric time-independent steady state to three-dimensional time-dependent oscillatory states. These flow states are judged through detecting spatiotemporal correlations between the behaviors of the particles and the variation of the temperature over the droplet surface. We find that the particle accumulation structures are realized in this geometry and that their structures vary as a function of the intensity of the thermocapillary effect.

Flow Cytometric Evaluation of Surface CD56 Expression on Activated Natural Killer Cells as Functional Marker.

Surface CD56 is the most important cell marker for defining NK cells. However, the relationship between the expression of surface CD56 and NK cell activity has not yet been elucidated in detail. Thirteen healthy volunteers were enrolled in the present study. Peripheral blood mononuclear cells (PBMCs) were stimulated with rIL-2 or rIL-12 (1, 10, 100 U/mL) for 18 h at 37°C. After incubation, surface CD56 expression on NK cells was evaluated using a flow cytometric analysis. A colorimetric-based lactate dehydrogenase (LDH) assay was used for experiments on cytotoxicity. IFN-γ mRNA gene expression was quantified by real-time PCR. The expression level of surface CD56 on NK cells, cytotoxicity, and IFN-γ mRNA gene expression were significantly increased by the rIL-2 and rIL-12 stimulations. In addition, a positive correlation was found between surface CD56 expression and cytotoxic activity or IFN-γ mRNA gene expression. We revealed that the quantification of surface CD56 expression was applicable to the evaluation of cytotoxicity and IFN-γ production in activated NK cells. These results suggest that the measurement of surface CD56 expression represent an easy and rapidly reproducible technique to evaluate the activated state of NK cells and monitor NK cell activity in immunotherapy. J. Med. Invest. 63: 199-203, August, 2016.

Experimental study on dynamics of coherent structures formed by inertial solid particles in three-dimensional periodic flows.

We present experimental results obtained under normal gravity on the dynamics of solid particles in periodic oscillatory thermocapillary-driven flows in a non-isothermal liquid bridge made of decane. Inertial particles of different densities and in the size range approximately 0.75-75 µm are able to form stable coherent structures (particle accumulation structures, or PASs). Two image processing techniques were developed and successfully applied to compute time required for an ensemble of particles to form a structure. It is shown that the formation time grows with the decrease of the Stokes number. The observations indicate the probable irrelevance of the memory term for these experiments. Two types of PAS were observed-single (SL-I) and double-loop (SL-II)-which sometimes co-existed. Only large or very dense particles may form an SL-II type structure. A number of novel features of the system were perceived. In some cases, intermittently stable structures emerged (their dynamics is characterized by alternating time intervals during which a structure exists and is destroyed). Whereas in most experiments we observed a conventional symmetric and centered PAS, there were cases when a long-term stable asymmetric structure appeared. Experiments wherein two different types of PAS-forming particles were used simultaneously revealed the destructive role of collisions between the particles on formation of structures.

SNPs rs4656317 and rs12071048 located within an enhancer in FCGR3A are in strong linkage disequilibrium with rs396991 and influence NK cell-mediated ADCC by transcriptional regulation.

CD16 receptors are mainly expresses on the surface of NK cells and mediate antibody-dependent cellular cytotoxicity (ADCC). The authors previously reported that NK cell-mediated ADCC is influenced by the single nucleotide polymorphism (SNP) rs396991 (T>G; F158V), and the structure and expression levels of CD16 differed among these genotypes. The authors examined haplotype frequency distributions among rs396991 and other SNPs, rs10917571 (G>T), rs4656317 (C>G), and rs12071048 (G>A), located in an enhancer of the FCGR3A gene. A total of 101 healthy Japanese were genotyped for the presence of these SNPs. The authors also measured ADCC activity, FCGR3A transcript levels, and surface CD16 expression on NK cells. We found that the regulatory SNPs (rSNPs) rs4656317 and rs12071048 were in strong linkage disequilibrium with rs396991. These two SNPs with major alleles had higher ADCC activity than those with minor alleles. In addition, FCGR3A transcript levels and surface CD16 expression levels were regulated by these SNPs. These findings suggest that NK cell-mediated ADCC could be influenced by transcriptional regulation of these rSNPs. These findings help to clarify our understanding of the linkage disequilibrium among functional SNPs in the FCGR3A gene, and provide a resource for investigating the roles of functional SNPs in NK cell-mediated ADCC.

The influence of NK cell-mediated ADCC: Structure and expression of the CD16 molecule differ among FcγRIIIa-V158F genotypes in healthy Japanese subjects.

NK cells express the CD16 (FcγRIIIa) receptor, which mediates antibody-dependent cellular cytotoxicity (ADCC), on their cell surface. Therefore, ADCC activity may be influenced by qualitative or quantitative changes in the CD16 molecule on NK cells. Responses to NK cell-mediated ADCC have been shown to depend on single nucleotide polymorphisms (SNPs) at FcγRIIIa amino acid position 158. However, a consensus has not yet been reached regarding differences in the structure and expression levels of the CD16 molecule among FcγRIIIa-V158F genotypes, which have not yet been adequately investigated in healthy Japanese individuals. We herein examined the influence of the FcγRIIIa polymorphism on ADCC, binding affinity of CD16 to the Fc region, FCGR3A gene expression, and cell-surface CD16 expression in healthy Japanese subjects. FcγRIIIa-V158F genotyping was performed for 101 subjects. The results obtained showed that all parameters analyzed increased in the order of V/V>V/F>F/F and were significantly higher in V/V subjects than in F/F subjects. Moreover, a positive correlation was observed between ADCC activity and binding affinity, FCGR3A transcript levels, and surface CD16 expression levels. These results suggest that the structure and expression of the CD16 molecule differs among FcγRIIIa-V158F genotypes, and the FcγRIIIa-V158F polymorphism may be represent a haplotype with other SNPs in regulatory regions in Japanese subjects.

Elevation of the temperature of liquid films caused by rapid rupturing.

Although there have been several experimental and numerical works on rapidly rupturing films, measurement of the spatial-temporal temperature during rupturing processes is lacking. Using molecular dynamics simulations, we show that a rupturing film with nanometer thickness generates a non-negligible temperature increase. We demonstrate a correlation between the rupture velocity, the temperature increase, and the initial film thickness. Our findings show that the temperature increase causes changes to the physical properties, which affect the film-rupturing behavior.

Effect of suspended particles on the drying process of a carrier-fluid droplet sitting on a solid surface.

We focus on an evaporation process of a volatile droplet on a temperature-controlled solid substrate. The process is strongly affected by suspending tiny particles inside the droplet, resulting in a well-known phenomenon called the "coffee stain problem." The target systems in this study are (1) the water-hydrophilic particle and (2) the water-ethanol mixture-hydrophilic particle. Spatio-temporal particle motion in the induced flow in the evaporation process is visualized by applying three-dimensional particle tracking velocimetry. The correlation between the particle behavior in the evaporation process and the morphological pattern of the droplet after dryout is also discussed.

Dynamic particle accumulation structure due to thermocapillary effect in noncylindrical half-zone liquid bridge.

We focus on the dynamic particle accumulation structure (PAS) due to the thermocapillary effect in a half-zone liquid bridge. In this study, by tracking particles in the liquid bridge and by measuring temperature on the free surface, we discuss the effects of a liquid bridge shape described by its volume ratio upon the shape of the PAS itself and motion of particle on the PAS. The variation of the liquid bridge volume ratio leads to a significant variation of the temperature gradient on the free surface, which results in difference of the shape of the PAS, especially width of the PAS blade. By considering the simply modeled particle motion, we explain that the width of the PAS blade is determined by several parameters, and we find that its variation is explained mainly by a drastic change of the axial velocity of the particle on the surface.

Detection of advancing edge and length of precursor film ahead of macroscopic contact line of droplet spreading on solid substrate.

The authors carried out an experimental study with a special interest on the dynamics of the fluid near the boundary line of three phases: solid-liquid-gas interface. A spreading droplet on a solid substrate is accompanied by the movement of a visible boundary line called the macroscopic contact line. Previous studies by various research groups have indicated the existence of a thin liquid film known as a precursor film ahead of the macroscopic contact line of the droplet. The present authors focused on the early stage of spreading and dedicated their special effort to detect the advancing edge of the precursor film by applying an interferometer with a high-speed camera and by noise cancellation of using time-frequency analysis of brightness variation. The authors estimated the precursor film length for comparison with theoretical predictions and investigated the effect of changing viscosity on the formation of the precursor film by using the method of detection described herein.

Characterization of factor XII Tenri, a rare CRM-negative factor XII deficiency.

Factor XII Tenri (Y34C), a rare cross-reacting material (CRM)-negative factor XII deficiency, was identified in a 71-yr-old Japanese woman with angina pectoris. In the patient's plasma, factor XII activity and antigen levels were only 1.6% and 5.0%, respectively, of those seen in a normal subject. Immunoblot analysis showed that the secreted factor XII Tenri existed not only as a monomer (76 kDa), but also in complexes with apparent molecular weights of approximately 115, 140, 190, 215, and 225 kDa. After reduction with 2-mercaptoethanol, the factor XII Tenri contained in the complexes was completely converted to monomeric form on immunoblot patterns. It appeared that some of the secreted factor XII Tenri formed several types of disulfide-linked complexes, including a factor XII-alpha1-microglobulin complex, through a newly generated Cys residue. The monomeric form of factor XII Tenri, like normal factor XII, was degraded into 2 major fragments with molecular weights of approximately 45 kDa and 30 kDa following mixing with activated partial-thromboplastin-time measuring reagent (cephalin and ellagic acid), whereas the factor XII Tenri that formed the complexes was not. This indicates that the factor XII Tenri present in disulfide-linked complexes with other proteins (and itself) is not converted to active forms, suggesting that attached proteins obstruct or delay the activation of factor XII via an inhibition of its binding to a negatively charged surface in vitro.

Helicobacter pylori infection up-regulates gland mucous cell-type mucins in gastric pyloric mucosa.

BACKGROUND: Two types of mucous cell are present in gastric mucosa: surface mucous cells (SMCs) and gland mucous cells (GMCs), which consist of cardiac gland cells, mucous neck cells, and pyloric gland cells. We have previously reported that the patterns of glycosylation of SMC mucins are reversibly altered by Helicobacter pylori infection. In this study, we evaluated the effects of H. pylori infection on the expression of GMC mucins in pyloric gland cells. METHODS: Gastric biopsy specimens from the antrums of 30 H. pylori-infected patients before and after eradication of H. pylori and 10 normal uninfected volunteers were examined by immunostaining for MUC6 (a core protein of GMC mucins), alpha1,4-N-acetyl-glucosaminyl transferase (alpha4GnT) (the glycosyltransferase which forms GlcNAcalpha1-4Galbeta-R), and GlcNAcalpha1-4Galbeta-R (a GMC mucin-specific glycan). RESULTS: MUC6, alpha4GnT, and HIK1083-reactive glycan were expressed in the cytoplasm, supranuclear region, and secretory granules in pyloric gland cells, respectively. The immunoreactivity of MUC6 and alpha4GnT, but not of GlcNAcalpha1-4Galbeta-R, in the pyloric gland increased in H. pylori-associated gastritis, and after the eradication of H. pylori, the increased expression of MUC6 and alpha4GnT in the gastric mucosa of H. pylori-infected patients decreased to almost normal levels. This up-regulation was correlated with the degree of inflammation. CONCLUSIONS: In addition to the synthesis of GMC mucins increasing reversibly, their metabolism or release may also increase reversibly in H. pylori-associated gastritis. The up-regulation of the expression of gastric GMC mucins may be involved in defense against H. pylori infection in the gastric surface mucous gel layer and on the gastric mucosa.

Specific autoantibodies to platelet glycoproteins in Epstein-Barr virus-associated immune thrombocytopenia.

In this study, we detected autoantibodies to platelet glycoproteins GPIIb/IIIa and GPIb/IX on platelets and in plasma in a patient with immune thrombocytopenia associated with Epstein-Barr virus-related infectious mononucleosis. In addition, we present our findings on the effectiveness of intravenous immunoglobulin therapy for immune thrombocytopenia associated with Epstein-Barr virus.

Internalization of beta-amyloid causes downregulation of apolipoprotein E mRNA expression in neuroblastoma cells.

Apolipoprotein (apo) E, like beta-amyloid (Abeta), is a key component of the senile plaques that characterize Alzheimer's disease (AD). Understanding how apoE participates in the formation of senile plaques is necessary to clarify the pathogenesis of AD; however, the mechanism remains unknown. In this study, we investigated the changes of cellular apoE and its mRNA level induced by addition of extracellular Abeta to neuroblastoma cells. The presence of > or = 1.0 micromol/L of Abeta induced a decrease of apoE mRNA expression and an increase in the immunofluorescence reactivity for intracellular apoE. Both Abeta and apoE were observed by electron-microscopy to be localized within lysosomes. The levels of intracellular apoE and its mRNA returned to the steady state time-dependently. These changes were attenuated by treatments with heparinase I or receptor-associated protein. These findings suggest that the internalized Abeta, along with cellular apoE, induces downregulation of apoE mRNA via a pathway possibly mediated by apoE receptors and heparin sulfate proteoglycans. A disorder of this physiological response could be linked to the development of AD.

Novel beta-thalassemia trait (IVS I-1 G-->C) in a Japanese family.

A rare beta-thalassemia mutation at the splicing junction [namely, G-->C in intervening sequence (IVS) I-1] was found in a Japanese family. The proband and his mother were heterozygous for the mutation. Analysis of mRNA extracted from the reticulocyte-rich fraction obtained from the proband's mother revealed that the mutant beta-globin gene did not produce any detectable, stable mRNA including exon 1 and exon 2, since the polymorphism in exon 1 on her mutant gene was not detected in the RT-PCR products.

Quantitative RT-PCR analysis demonstrates that synthesis of the recombinant fibrinogen is dependent on the transcription and synthesis of gamma-chain.

BACKGROUND: The purpose of this study was to examine the relationship between the production of secreted fibrinogen and the synthesis of gamma-chain mRNA. METHODS: We transfected a gamma-chain expression vector into Chinese hamster ovary cells already expressing both Aalpha- and Bbeta-chains of fibrinogen and measured fibrinogen output concentrations by ELISA. We quantified both gamma-chain and Bbeta-chain mRNA concentrations using the recently developed TaqMan fluorogenic detection system. RESULTS: The concentration of secreted fibrinogen into the media positively correlated with the amount of fibrinogen contained in the cell lysates. Additionally, quantitative mRNA assays revealed that the fibrinogen concentration in the cell lysates correlated well with the concentration of gamma-chain mRNA (r=0.7077, p<0.01) but not with the concentration of Bbeta-chain mRNA (r=0.0224, NS). CONCLUSIONS: These results demonstrate that the amount of recombinant fibrinogen produced in cells transfected with the gamma-chain vector, also expressing normal Aalpha- and Bbeta-chains, is dependent on the transcription of gamma-chain mRNA. Namely, in this recombinant expression system using a two-step transfection procedure, gamma-chain synthesis is the rate-limiting factor for fibrinogen production. This quantitative method to measure mRNA may prove very useful for further in vivo analysis of fibrinogen gene transcription.