Quantitative evaluation of interaction force of fibrinogen at well-defined surfaces with various structures

<div><p>The effects of functional groups and structures at the surface of biomaterials on protein adsorption were examined using direct interaction force measurements. Three kinds of surface structures were evaluated: polymer brushes, self-assembled monolayers with low molecular weight compounds, and surfaces with conventional polymer coatings. These surfaces had various functional groups including phosphorylcholine (PC) group. The surface characterization demonstrated that surface wettability and flexibility depended on both the structure of the surface and the functional groups at the surface. The interactions of protein with these surfaces were evaluated by a force vs. distance curve using an atomic force microscope (AFM). We used fibrinogen as the protein, and the fibrinogen was immobilized on the surface of the AFM cantilever by a conventional technique. It was observed that the interaction force of fibrinogen was strongly related to surface hydrophobic nature and flexibility. That is, the interaction force increased with the increasing hydrophobic nature of the surface. The relationship between the amount of fibrinogen adsorbed on the surface and the interaction force showed good correlation in the range of fibrinogen adsorption from 0 to 250 ng/cm², that is, in a monolayered adsorption region. The interaction force decreased with increasing surface viscoelasticity. The most effective surface for preventing fibrinogen adsorption was the polymer brush surface with phosphorylcholine (PC) groups, that is, poly(2-methacryloyloxyethyl phosphorylcholine) brush. The interaction force of this sample was less than 0.1 nN and the amount of fibrinogen adsorbed on the surface was minimal. It was found that the evaluation of protein adsorption based on the interaction force measurement is useful for low-protein adsorption surfaces. It was demonstrated that an extremely hydrophilic and flexible surface could weaken the protein interactions at the surface, resulting in greater resistance to protein adsorption.</p></div

Constructing Magnetic Ion Accelerator at Na_2/3Ni_1/3Mn_2/3O₂ Surface for Sodium Ion Batteries

Surface ion transportation and structural stability are generally the key factors determining the electrochemical performance of a specific electrode for secondary batteries. Therefore, building an effective and stable interface layer becomes the bottleneck for long-life and high-performance batteries. This study is the first to design and construct a magnetic Fe3O4 interfacial layer on the Na2/3Ni1/3Mn2/3O2 surface. Preliminary analysis and calculations indicated that the the Fe3O4 magnetic layer played a role as a surface ion accelerator, which effectively ameliorated the interfacial kinetic behavior through dispersing the aggregated ions at a tangential orientation under the Lorentz force. Electrochemical tests substantiated that the decorated cathode delivered a high capacity of 87 mA h g–1 and a capacity retention of 76% after 500 cycles under a rate of 5 C. This finding in the surface magnetic ion accelerator provides insight into efficient electrode design and applications of surface physical fields to enhance ion transportation and structural stability for advanced secondary batteries

Evaluation of New Reference Genes in Papaya for Accurate Transcript Normalization under Different Experimental Conditions

<div><p>Real-time reverse transcription PCR (RT-qPCR) is a preferred method for rapid and accurate quantification of gene expression studies. Appropriate application of RT-qPCR requires accurate normalization though the use of reference genes. As no single reference gene is universally suitable for all experiments, thus reference gene(s) validation under different experimental conditions is crucial for RT-qPCR analysis. To date, only a few studies on reference genes have been done in other plants but none in papaya. In the present work, we selected 21 candidate reference genes, and evaluated their expression stability in 246 papaya fruit samples using three algorithms, geNorm, NormFinder and RefFinder. The samples consisted of 13 sets collected under different experimental conditions, including various tissues, different storage temperatures, different cultivars, developmental stages, postharvest ripening, modified atmosphere packaging, 1-methylcyclopropene (1-MCP) treatment, hot water treatment, biotic stress and hormone treatment. Our results demonstrated that expression stability varied greatly between reference genes and that different suitable reference gene(s) or combination of reference genes for normalization should be validated according to the experimental conditions. In general, the internal reference genes <em>EIF</em> (Eukaryotic initiation factor 4A), <em>TBP1</em> (TATA binding protein 1) and <em>TBP2</em> (TATA binding protein 2) genes had a good performance under most experimental conditions, whereas the most widely present used reference genes, <em>ACTIN</em> (Actin 2), <em>18S rRNA</em> (18S ribosomal RNA) and <em>GAPDH</em> (Glyceraldehyde-3-phosphate dehydrogenase) were not suitable in many experimental conditions. In addition, two commonly used programs, geNorm and Normfinder, were proved sufficient for the validation. This work provides the first systematic analysis for the selection of superior reference genes for accurate transcript normalization in papaya under different experimental conditions.</p> </div

Summary of the experimental conditions and samples used in present study.

<p>#indicated that the sample dates including two types: two treatments were 6 and one was 7.</p

Constructing Magnetic Ion Accelerator at Na_2/3Ni_1/3Mn_2/3O₂ Surface for Sodium Ion Batteries

Surface ion transportation and structural stability are generally the key factors determining the electrochemical performance of a specific electrode for secondary batteries. Therefore, building an effective and stable interface layer becomes the bottleneck for long-life and high-performance batteries. This study is the first to design and construct a magnetic Fe3O4 interfacial layer on the Na2/3Ni1/3Mn2/3O2 surface. Preliminary analysis and calculations indicated that the the Fe3O4 magnetic layer played a role as a surface ion accelerator, which effectively ameliorated the interfacial kinetic behavior through dispersing the aggregated ions at a tangential orientation under the Lorentz force. Electrochemical tests substantiated that the decorated cathode delivered a high capacity of 87 mA h g–1 and a capacity retention of 76% after 500 cycles under a rate of 5 C. This finding in the surface magnetic ion accelerator provides insight into efficient electrode design and applications of surface physical fields to enhance ion transportation and structural stability for advanced secondary batteries

Constructing Magnetic Ion Accelerator at Na_2/3Ni_1/3Mn_2/3O₂ Surface for Sodium Ion Batteries

Surface ion transportation and structural stability are generally the key factors determining the electrochemical performance of a specific electrode for secondary batteries. Therefore, building an effective and stable interface layer becomes the bottleneck for long-life and high-performance batteries. This study is the first to design and construct a magnetic Fe3O4 interfacial layer on the Na2/3Ni1/3Mn2/3O2 surface. Preliminary analysis and calculations indicated that the the Fe3O4 magnetic layer played a role as a surface ion accelerator, which effectively ameliorated the interfacial kinetic behavior through dispersing the aggregated ions at a tangential orientation under the Lorentz force. Electrochemical tests substantiated that the decorated cathode delivered a high capacity of 87 mA h g–1 and a capacity retention of 76% after 500 cycles under a rate of 5 C. This finding in the surface magnetic ion accelerator provides insight into efficient electrode design and applications of surface physical fields to enhance ion transportation and structural stability for advanced secondary batteries

Consensus of stability ranking of the reference gene estimated by geNorm and NormFinder.

<p>Consensus of stability ranking of the reference gene estimated by geNorm and NormFinder.</p

Specificity of primer pairs for RT-qPCR amplification.

<p>Equal amounts of cDNAs from all tested samples were mixed as the template. 2.5% non-denaturing agarose gel electrophoresis showed amplification of a specific product of the expected size for each reference gene. M represented DNA size marker.</p

Determination of the optimal number of reference genes.

<p>Pair-wise variation (V) calculated by geNorm to determine the minimum number of reference genes for accurate normalization in different experiment conditions. Arrow indicates the optimal number of genes for normalization in each sample sets.</p

RT-qPCR CT values for the candidate reference genes.

<p>Expression data displayed as CT values for each reference gene in all papaya samples. A line across the box is depicted as the median. The box indicates the 25th and 75th percentiles. Whiskers represent the maximum and minimum values.</p