Controlling Marangoni induced instabilities in spin-cast polymer films: how to prepare uniform films

In both research and industrial settings spin coating is extensively used to prepare highly uniform thin polymer films. However, under certain conditions, spin coating results in films with non-uniform surface morphologies. Although the spin coating process has been extensively studied, the origin of these morphologies is not fully understood and the formation of non-uniform spincast films remains a practical problem. Here we report on experiments demonstrating that the formation of surface instabilities during spin coating is dependent on temperature. Our results suggest that non-uniform spincast films form as a result of the Marangoni effect, which describes flow due to surface tension gradients. We find that both the wavelength and amplitude of the pattern increase with temperature. Finally, and most important from a practical viewpoint, the non-uniformities in the film thickness can be entirely avoided simply by lowering the spin coating temperature.Comment: 8 pages, 6 figures. electronic supplementary material: 3 pages, 4 figure

Diffusion tensor magnetic resonance imaging-derived myocardial fiber disarray in hypertensive left ventricular hypertrophy: visualization, quantification and the effect on mechanical function

Left ventricular hypertrophy induced by systemic hypertension is generally regarded a morphological precursor of unfortunate cardiovascular events. Myocardial fiber disarray has been long recognized as a prevalent hallmark of this pathology. In this chapter, ex vivo diffusion tensor magnetic resonance imaging is employed to delineate the regional loss of myocardial organization that is present in the excised heart of a spontaneously hypertensive rat, as opposed to a control. Fiber tracking results are provided that illustrate in great detail the alterations in the integrity of cardiac muscle microstructure due to the disease. A quantitative analysis is also performed. Another contribution of this chapter is the model-based assessment of the role of the myofiber disarray in modulating the mechanical properties of the myocardium. The results of this study improve our understanding of the structural remodeling mechanisms that are associated with hypetensive left ventricular hypertrophy and their role

A Comparison of the Genetic Shaft Types of Some Karst Areas Based on Their Specific Shaft Lengths

Shaft development can be documented on the basis of comparative studiesof specific shaft lengths and shaft patterns. We calculated the specific lengthof shafts and the average specific shaft length of the shafts in some karstareas and we investigated the relation between the altitude of shaft floorsand the specific shaft length. Taking the registered specific shaft lengthsand the shaft patterns into consideration, it can be stated that some partsof the shafts developed paragenetically in the studied karst areas. In theBakony Region, this was caused by surface water influx, rise of karst waterlevel, and their simultaneous effect. As a result, shaft systems, bifurcatingshafts and storeyed shafts developed. On glaciokarst areas, shafts mayconstitute a system with phreatic passages: either because a phreatic environment developed in the vadose zone due to the permanent impoundmentof karst water or because a phreatic passage got into the vadose zone sincethe karst became elevated. On the studied karst areas, the following shaftdevelopment types are distinguished: glacial-high mountain surface flooddevelopment type (1), glacial-high mountain karst water and surface flooddevelopment type (2), glacial karst water and surface flood later phreaticdevelopment type (3), shaft with a passage that got into the vadose zone (4)

Sub-Glass-Transition Temperature Interface Formation Between an Immiscible Glass Rubber Pair

ABSTRACT: We used neutron reflectivity to measure the interfacial width in the immiscible system polystyrene/poly(n-butyl methacrylate) (PS/PnBMA). Measurements were made on the same samples at temperatures ranging from below the glasstransition temperature (T g ) of PS to slightly above. We observed significant broadening of the interface at temperatures below the T g of PS, indicating chain mobility below the bulk T g value. The interfacial width exhibited a plateau at a value of 20 Å in the temperature range of 365 K Ͻ T Ͻ 377 K. A control experiment involving hydrogenated and deuterated PS films (hPS/dPS) showed no such broadening over the same temperature region. The results are consistent with a reduction of the T g of PS in the interfacial region of ϳ20 K

Calcium Handling Defects and Cardiac Arrhythmia Syndromes

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Development of microsatellite markers for Rhodiola rosea

Rhodiola rosea L. is an important adaptogen medicinal plant. In this study two new microsatellite markers were developed. The assessment of the genetic diversity of R. rosea has recently started with molecular markers, but only a few species-specific microsatellite markers have been published so far. However the small number of markers allows only a limited insight into the genetic variability of the species therefore the aim of our work was to develop new microsatellite markers for R. rosea with a microsatellite enrichment library technique. Genomic DNA was cleaved with an endonuclease enzyme followed by adaptor ligation and PCR amplification. DNA fragments that contained microsatellites were first isolated using a biotin-streptavidin linkage based magnetic selection and then cloned into plasmids. Out of forty-three sequenced clones three contained  microsatellites, in these cases primers were designed for the amplification of the microsatellite repeats. The newly developed primer pairs were tested on individuals from distant R. rosea populations and the variability of the amplified fragments was estimated by fragment-length analysis. The locus RhpB14a was found to be monomorphic while RhpB14b and RhpB13 were polymorphic. As a result of the present study, two novel variable microsatellite loci were identified in the genome of R. rosea

Development of microsatellite markers for Rhodiola rosea

Rhodiola rosea L. is an important adaptogen medicinal plant. In this study two new microsatellite markers were developed. The assessment of the genetic diversity of R. rosea has recently started with molecular markers, but only a few species-specific microsatellite markers have been published so far. However the small number of markers allows only a limited insight into the genetic variability of the species therefore the aim of our work was to develop new microsatellite markers for R. rosea with a microsatellite enrichment library technique. Genomic DNA was cleaved with an endonuclease enzyme followed by adaptor ligation and PCR amplification. DNA fragments that contained microsatellites were first isolated using a biotin-streptavidin linkage based magnetic selection and then cloned into plasmids. Out of forty-three sequenced clones three contained  microsatellites, in these cases primers were designed for the amplification of the microsatellite repeats. The newly developed primer pairs were tested on individuals from distant R. rosea populations and the variability of the amplified fragments was estimated by fragment-length analysis. The locus RhpB14a was found to be monomorphic while RhpB14b and RhpB13 were polymorphic. As a result of the present study, two novel variable microsatellite loci were identified in the genome of R. rosea