Micropatterning Research Articles

The elusive type 2 diabetes individual achieving tight blood pressure target: A phenotypic study

Background To describe the characteristics (therapeutic, physical and behavioural) associated with achievement of tight blood pressure (BP) control and its prevalence in type 2 diabetes (T2DM) patients. Methods Cross-sectional observational cohort study. 673 hypertensive patients with T2DM, treated with one or more antihypertensive drugs. Sociodemographic, clinical and laboratory variables compared between patients achieving BP targets (goal-achievers [GAs]) and non-goal-achievers (non-GAs). Results Only 111 patients (16%) achieved BP goals. Markers-factors connected with failure of BP control in non-GAs were: sub-Saharan African ethno-geographical origin, high alcohol consumption and low educational level. Total cholesterol was significantly lower and glycaemic control significantly better in GAs. In addition, prevalence of micro- or macro-albuminuria was clearly lower in GAs. As regards cardiovascular drugs, statins were used to a greater extent by the GAs. Finally, GAs and non-GAs had the same pattern of micro- and macro-vascular diabetic diseases, as well as similar estimated 10-year absolute cardiovascular risk scores. Conclusions This cross-sectional study characterized variables associated with an unmet need in drug-treatment of hypertension in T2DM. One might surmise that using higher dosage and/or number of antihypertensive agents will be required in most T2DM patients in order to reach targets, including new antihypertensive agents.

Biogeographical patterns of freshwater micro‐ and macroorganisms: a comparison between phytoplankton, zooplankton and fish in the eastern Mediterranean

AbstractAim We investigated the biogeographical patterns of phytoplankton, zooplankton and fish in freshwater ecosystems. We tested whether spatial distance or environmental heterogeneity act as potential factors controlling community composition.Location Northern and central Greece, eastern Mediterranean.Method Data on 310 phytoplankton, 72 zooplankton and 37 fish species were collected from seven freshwater systems. Species occurrence data were used to generate similarity matrices describing community composition. We performed Mantel tests to compare spatial patterns in community composition of phytoplankton, zooplankton and fish. Next, we examined the correlation between geographical distance and the degree of similarity in community composition. The analysis was repeated for different taxonomic, trophic and size‐based groups of the microorganisms studied. We assessed different environmental variables (topographic and limnological) as predictors of community composition.Results Phytoplankton community composition showed a strong positive correlation with environmental heterogeneity but was not correlated with the geographical distance between systems. Zooplankton community composition was unrelated to geographical distance and was only weakly correlated with environmental variables. In contrast, fish community similarity decayed significantly with distance. We found no relationship along all pairwise comparisons of the compositional matrices of the three groups. The pairwise comparisons of the different taxonomic, trophic and size‐based groups of the microorganism communities studied were in accordance with the results for the entire microorganism community.Main conclusions Our results support the proposition that the biogeography of microorganisms does not demonstrate a distance–decay pattern and further suggest that, in reality, the drivers of distribution depend on the specific community examined. In contrast, the biogeography of macroorganisms was affected by geographical distance. These differences reflect the dispersal abilities of the different organisms. The microorganisms exhibit passive dispersal through the air, with local environmental conditions structuring their community composition. On the other hand, for macroorganisms such as fish, the terrestrial environment could pose barriers to their dispersal; with fish structuring distinctive communities over greater distances. Overall, we suggest that the biogeography of freshwater phytoplankton and zooplankton reflects contemporary environmental conditions, while the biogeographical patterns for fish inhabiting the same systems are related to factors affecting their dispersal ability.

Coffee-Ring Effect-Based Three Dimensional Patterning of Micro/Nanoparticle Assembly with a Single Droplet

We develop a novel patterning technique to create 3D patterns of micro and nanoparticle assembly via evaporative self-assembly based on the coffee-ring effect of an evaporating suspension. The principle of the technique is analyzed theoretically by the scaling analysis of main parameters of the process and the scaling effect, the effect of the volume, the concentration of the suspension, and the effect of surface treatment on the patterning are studied. On the basis of the presented technique, we demonstrate that the patterns of 3D assembly of various sizes of microparticles (Silica), metal oxide nanoparticles (TiO(2), ZnO), and metallic nanoparticles (Ag) can be successfully generated by low-concentrated particle suspension (1.25-5 wt %) without additional sintering steps, and we also show the geometries of the patterns can be finely controlled by adjusting the parameters of the process.

Small RNA expression and strain specificity in the rat.

BackgroundDigital gene expression (DGE) profiling has become an established tool to study RNA expression. Here, we provide an in-depth analysis of small RNA DGE profiles from two different rat strains (BN-Lx and SHR) from six different rat tissues (spleen, liver, brain, testis, heart, kidney). We describe the expression patterns of known and novel micro (mi)RNAs and piwi-interacting (pi)RNAs.ResultsWe confirmed the expression of 588 known miRNAs (54 in antisense orientation) and identified 56 miRNAs homologous to known human or mouse miRNAs, as well as 45 new rat miRNAs. Furthermore, we confirmed specific A to I editing in brain for mir-376a/b/c and identified mir-377 as a novel editing target. In accordance with earlier findings, we observed a highly tissue-specific expression pattern for all tissues analyzed. The brain was found to express the highest number of tissue-specific miRNAs, followed by testis. Notably, our experiments also revealed robust strain-specific differential miRNA expression in the liver that is caused by genetic variation between the strains. Finally, we identified two types of germline-specific piRNAs in testis, mapping either to transposons or in strand-specific clusters.ConclusionsTaken together, the small RNA compendium described here advances the annotation of small RNAs in the rat genome. Strain and tissue-specific expression patterns furthermore provide a strong basis for studying the role of small RNAs in regulatory networks as well as biological process like physiology and neurobiology that are extensively studied in this model system.

Spatial Patterns of Plastic Debris along Estuarine Shorelines

The human population generates vast quantities of waste material. Macro (>1 mm) and microscopic (<1 mm) fragments of plastic debris represent a substantial contamination problem. Here, we test hypotheses about the influence of wind and depositional regime on spatial patterns of micro- and macro-plastic debris within the Tamar Estuary, UK. Debris was identified to the type of polymer using Fourier-transform infrared spectroscopy (FT-IR) and categorized according to density. In terms of abundance, microplastic accounted for 65% of debris recorded and mainly comprised polyvinylchloride, polyester, and polyamide. Generally, there were greater quantities of plastic at downwind sites. For macroplastic, there were clear patterns of distribution for less dense items, while for microplastic debris, clear patterns were for denser material. Small particles of sediment and plastic are both likely to settle slowly from the water-column and are likely to be transported by the flow of water and be deposited in areas where the movements of water are slower. There was, however, no relationship between the abundance of microplastic and the proportion of clay in sediments from the strandline. These results illustrate how FT-IR spectroscopy can be used to identify the different types of plastic and in this case was used to indicate spatial patterns, demonstrating habitats that are downwind acting as potential sinks for the accumulation of debris.

Electron beam lithography using plasma polymerized hexane as resist

We present electron beam lithography using thin layers of plasma polymerized hexane as resist, as an alternative for conventional spincoated resists. Hexane is chosen due to the possible bioapplications, as well as the relatively simple polymerization chemistry. Successful patterning of micro- and nanopatterns are achieved with doses of 5000–25000 μC cm −2. Resist polarity is negative and features with a linewidth down to 150 nm are obtained. The patterns have also been used as a mask for a subsequent etch of silicon, with a selectivity comparable to PMMA, and as the base for a lift-off process.

Quantitative relationship between maximum growth rates and the intracellular pattern of α-esterase and β-esterase activity of leguminous infecting bacteria

Sixteen strains belonging to three families of the Rhizobiales order (Bradyrhizobiaceae, Phyllobacteriaceae and Rhizobiaceae) were evaluated according their specific growth rates (micro) and the activity of intracellular alpha-esterase and beta-esterase isoenzymes. The average esterase activity of 48 isoenzymes assayed belonging to five strains with low (micro(max) = 0.08-0.12 h(-1)), four medium (micro(max) = 0.13-0.22 h(-1)) and seven high (micro(max) = 0.24-0.28 h(-1)) growth rate values were 22.1 +/- 4.3; 8.7 +/- 2.2 and 3.9 +/-1.7 U g(-1) respectively. An inversely proportional relationship between the activity of the whole pattern of esterases and micro(max) was found. Our results illustrate a feature of intracellular esterases, ascribable in a variety of cellular functions, which might be related to characteristics micro(max) of legume infecting bacteria.

M4-6 マイクロ電極を用いた電界駆動型マイクロポンプ(M4 ポンプ,液滴・気泡駆動)

M4-6 マイクロ電極を用いた電界駆動型マイクロポンプ(M4 ポンプ,液滴・気泡駆動)

Thermal patterning of amorphous fluoropolymer layers

We study thermal patterning of micro- and nanoscale thin films of low-surface energy amorphous fluoropolymers, which circumvents some of the limitations of conventional photolithography techniques. Controlled heating of a spin-coated Teflon AF ® layer leads to reduction in the residual solvent concentration and the dissociation rate. When immersed in a suitable solvent, unheated areas form thick gel-like regions, which can be efficiently removed through mechanical agitation. The kinetics of the solvent evaporation and dissociation processes is studied. Micro-heaters are used as localized heat sources to demonstrate thermal patterning of microscale structures.

Control of Human Embryonic Stem Cell Colony and Aggregate Size Heterogeneity Influences Differentiation Trajectories

To better understand endogenous parameters that influence pluripotent cell differentiation we used human embryonic stem cells (hESCs) as a model system. We demonstrate that differentiation trajectories in aggregate (embryoid body [EB])-induced differentiation, a common approach to mimic some of the spatial and temporal aspects of in vivo development, are affected by three factors: input hESC composition, input hESC colony size, and EB size. Using a microcontact printing approach, size-specified hESC colonies were formed by plating single-cell suspensions onto micropatterned (MP) extracellular matrix islands. Subsequently, size-controlled EBs were formed by transferring entire colonies into suspension culture enabling the independent investigation of colony and aggregate size effects on differentiation induction. Gene and protein expression analysis of MP-hESC populations revealed that the ratio of Gata6 (endoderm-associated marker) to Pax6 (neural-associated marker) expression increased with decreasing colony size. Moreover, upon forming EBs from these MP-hESCs, we observed that differentiation trajectories were affected by both colony and EB size-influenced parameters. In MP-EBs generated from endoderm-biased (high Gata6/Pax6) input hESCs, higher mesoderm and cardiac induction was observed at larger EB sizes. Conversely, neural-biased (low Gata6/Pax6) input hESCs generated MP-EBs that exhibited higher cardiac induction in smaller EBs. Our analysis demonstrates that heterogeneity in hESC colony and aggregate size, typical in most differentiation strategies, produces subsets of appropriate conditions for differentiation into specific cell types. Moreover, our findings suggest that the local microenvironment modulates endogenous parameters that can be used to influence pluripotent cell differentiation trajectories.

Endothelial cell cytoskeletal alignment independent of fluid shear stress on micropatterned surfaces

Endothelial cells (ECs) in athero-protective regions are elongated with actin and microtubule fibers aligned parallel to the direction of blood flow. Fluid shear stress (FSS) affects EC shape and functions, but little is known about shape-dependent EC properties that are independent of FSS. To evaluate these properties, ECs were elongated on micropatterned (MP) 25 μm wide collagen-coated lanes (MPECs) and characterized by cell shape index, actin and microtubule alignment, and polarization of the microtubule-organizing center (MTOC). ECs on non-patterned surfaces were also exposed to FSS. MPEC elongation was microtubule-dependent (and actin-independent); shape indices and cytoskeletal alignment were comparable to FSS-elongated ECs. Cytoskeletal alignment was lost when MPECs were exposed to perpendicular FSS, but not parallel FSS. MTOC polarization was FSS-dependent. Thus, by isolating EC elongation and cytoskeletal alignment from FSS, micropatterning creates a platform for studying EC shape-related cellular functions that are independent of FSS.

Directional shear flow and Rho activation prevent the endothelial cell apoptosis induced by micropatterned anisotropic geometry

To study the roles of anisotropic cell morphology and directionality of mechanical force in apoptosis, the spreading of human umbilical vein endothelial cells (HUVECs) was constrained by growing on micropatterned (MP) strips of fibronectin (FN, 20 microg/cm2) with widths of 15, 30, and 60 microm on silicone membrane. Cells on 30- and 60-microm strips, like cells on a nonpatterned (NP) surface coated with FN, showed clear actin stress fibers with anchoring spots of phosphorylated focal adhesion kinase (p-FAK) and no significant apoptosis. On 15-microm strips, cells had few stress fibers, no p-FAK, and significant apoptosis. After seeding for 12 h, the cells were subjected to pulsatile shear stress (12+/-4 dyn/cm2) parallel or perpendicular to MP strips, or kept under static condition. Parallel flow caused cell elongation with enhanced stress fibers and p-FAK, and a reduction in apoptosis, but perpendicular flow did not. The Rho inhibitory C3 exoenzyme abolished the effects of parallel flow. RhoV14, the constitutively active Rho, enhanced stress fibers and p-FAK, and prevented apoptosis of HUVECs on 15-microm strips under static condition. RhoV14 also reduced cell apoptosis under both parallel and perpendicular flows. Our results indicate that cell apoptosis can be modulated by changes in ECM micropatterning, anisotropic cell morphology, and mechanical forces. These extracellular microenvironment factors affect cell survival through alterations in Rho GTPase activity, stress fiber organization, and FAK phosphorylation.

Tissue engineering of bone on micropatterned biodegradable polyester films

In this study, the effect of cell alignment on proliferation and phenotype expression of rat bone marrow derived osteoblasts on micropatterned (MP) PHBV and P( l/ d, l)LA films with 27 μm wide parallel microgrooves was investigated. Immobilization of fibrinogen (Fb) on film surface by adsorption increased hydrophilicity, while covalent immobilization decreased it. Amount of Fb immobilized was significantly higher upon covalent bonding (153.1±42.4 μg Fb/cm 2) than when adsorbed (10.0±3.3 μg Fb/cm 2). It was observed that the presence of MP did not influence cell proliferation in the long run. Osteoblasts on MP films with adsorbed (MP Fb a) and covalently immobilized Fb (MP Fb i) aligned parallel to the groove axis with mean deviation angles of 10.59±23.47 and 29.02±33.03°, respectively, while on tissue culture polystyrene (TCP), on unpatterned films (UNP) and on UNP with adsorbed Fb (UNP Fb a) alignment with an arbitrary axis was much higher: 46.66±24.98, 48.72±31.19, 47.74±27.29 degrees, respectively. Fb-free MP films were not effective in cell alignment, and clumps were formed. Cell alignment achieved on MP Fb a films did not influence cell proliferation, but increased differentiation, as shown by ALP activity per cell and the evenness and the amount of calcium phosphate deposition. It was concluded that orientation of cells was influential on their differentiation and also, MP cell carriers with chemical cues on their surfaces are important in improving tissue repair.

WHEN LESS IS MORE: EXPERIMENTAL EVIDENCE FOR TENACITY ENHANCEMENT BY DIVISION OF CONTACT AREA

Most recent data on hairy systems demonstrated their excellent adhesion and high reliability of contact. In contrast to smooth systems, some hairy systems seem to operate with dry adhesion and do not require supplementary fluids in the contact area. Contacting surfaces in such devices are subdivided into patterns of micro- or nanostructures with a high aspect ratio (setae, hairs, pins). The size of single points gets smaller and their density gets higher as the body mass increases. Previous authors explained this general trend by applying the JKR theory, according to which splitting up the contact into finer subcontacts increases adhesion. Fundamental importance of contact splitting for adhesion on smooth and rough substrata has been previously explained by a very small effective elastic modulus of the fibre array. This article provides the first experimental evidence of adhesion enhancement by division of contact area. A patterned surface made out of polyvinylsiloxane (PVS) has significantly higher adhesion on a glass surface than a smooth sample made out of the same material. This effect is even more pronounced on curved substrata. An additional advantage of patterned surfaces is the reliability of contact on various surface profiles and the increased tolerance to defects of individual contacts.

Micro- and nano-patterning of polymers

Micro- and nano-patterning of polymers is essential in nanoscience and nanotechnology. Single macromolecule is a particle with nano-scale dimension; polymers have multi-structure, various configurations, and ability of forming blends with varying polymers or copolymers with different monomers, which will result in plenty of patterns of micro- and nano-scale. Besides, special physical and mechanical properties of polymers will not only be used to make patterns in many existing microfabrication technologies, but also develop new patterning techniques. The topic of micro and nano-patterning of polymers has been granted as a key project by the National Natural Science Foundation of China.

High-throughput techniques for analyzing complex bacterial communities.

A more complete understanding of microbial diversity and the environmental processes they control will require much more than a biotic inventory. It will require a deeper understanding of the basic features of systems organization and inter-population interactions. Communities, not total biomass, control net process rates driving the biogeochemical cycles sustaining the biosphere. Although the general patterns of macroorganismal diversity are relatively well known, spatial and temporal patterns of microorganismal diversity are essentially unknown. Having tools capable of resolving these patterns is a prerequisite to developing an understanding of the relationship between community structure and function. This talk discusses conceptual and technical developments that now provide the framework for systematically resolving temporal and spatial patterns of microorganisms and relating those patterns to processes at local and system levels. Of particular emphasis will be ongoing studies using highly parallel analyses with DNA microarrays for intensive monitoring of microbial populations in environmental systems. Although microarray technology is reasonably well established for studies of model organisms in well-defined laboratory settings, the application of this technology to environmental systems of uncharacterized diversity imposes additional demands on implementation; in particular, the requirement for optimized discrimination between target and non-target nucleic acids in complex, and undefined, mixtures. To increase the resolving power (information content) of our DNA microarray format, we are investigating the use of thermal dissociation of hybrids immobilized on individual array elements to resolve target and non-target sequences that differ by a single nucleotide. These studies, combined with specialized algorithms for optimizing the readout of the microarray should serve for informed environmental application. Initial studies have validated the general approach for analyses of sediment systems.

Electrochemically Directed Micropatterning of a Conducting Polymer Covalently Bound to Silicon

Electrochemically Directed Micropatterning of a Conducting Polymer Covalently Bound to Silicon

1002 繊毛型多リンク微小水中推進機構の動作生成

1002 繊毛型多リンク微小水中推進機構の動作生成

A problem‐based phenomenological growth model for small manufacturing firms

The development of small firms tends to follow certain growth patterns usually referred to as business growth models. This paper reports on the conceptualisation of a “problem‐based phenomenological life cycle model”, which delineates the growth pattern of micro and small manufacturing firms in Cyprus. The empirically validated model offers guidance to small business managers, financiers and advisers as to the challenges and growth complexities accompanying the transitions taking place in small businesses as they develop along their organisational life cycle. Enhanced understanding of the barriers to the development of small business contributes to the better design of policy initiatives that seek to foster the survival, sustainable growth and prosperity of small enterprises.

A repetitive DNA sequence common to the different B chromosomes of the genus Brachycome

Dot-like micro B chromosomes of Brachycome dichromosomatica were analysed for their sequence composition. Southern hybridization patterns of a total micro B probe to genomic DNA from plants with and without micro Bs demonstrated that the micro Bs shared sequences with the A chromosomes. In addition to telomere, rDNA and common A and B chromosome sequences, a new B-specific, highly methylated tandem repeat (Bdm29) was detected. After in situ hybridization with Bdm29 the entire micro B chromosome was labelled and clustering of the condensed micro Bs could be observed at interphase. A high number of Bdm29-like sequences were also found in the larger B chromosomes of B. dichromosomatica and in other Bs within the genus Brachycome.