Improved Synchronization Criteria for Chaotic Neural Networks with Sampled-data Control Subject to Actuator Saturation

International Journal of Control, Automation and Systems - In this paper, the synchronization problem for chaotic neural networks with sampled-data control and actuator saturation is investigated....     

Synthesis of Kisspeptin-Mimicking Fragments and Investigation of their Skin Anti-Aging Effects

In recent years, a number of active materials have been developed to provide anti-aging benefits for skin and, among them, peptides have been considered the most promising candidate due to their remarkable and long-lasting anti-wrinkle activity. Recent studies have begun to elucidate the relationship between the secretion of emotion-related hormones and skin aging. Kisspeptin, a neuropeptide encoded by the KISS1 gene, has gained attention in reproductive endocrinology since it stimulates the reproductive axis in the hypothalamus; however, the effects of Kisspeptin on skin have not been studied yet. In this study, we synthesized Kisspeptin-10 and Kisspeptin-E, which are biologically active fragments, to mimic the action of Kisspeptin. Next, we demonstrated the anti-aging effects of the Kisspeptin-mimicking fragments using UV-induced skin aging models, such as UV-induced human dermal fibroblasts (Hs68) and human skin explants. Kisspeptin-E suppressed UV-induced 11 beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) stimulation leading to a regulation of skin aging related genes, including type I procollagen, matrix metalloproteinases-1 (MMP-1), interleukin-6 (IL-6), and IL-8, and rescued the skin integrity. Taken together, these results suggest that Kisspeptin-E could be useful to improve UV-induced skin aging by modulating expression of stress related genes, such as 11β-HSD1.     

Significantly Increased Solubility of Carbon Nanotubes in Superacid by Oxidation and Their Assembly into High‐Performance Fibers

This study demonstrates that small amount of oxygen incorporated into carbon nanotubes (CNTs) during the purification process greatly increases their solubility in chlorosulfonic acid (CSA). Using as‐purchased and unpurified CNT powders, the optimal purification process is established to significantly increase the solubility of CNTs in CSA, and spin CNT fibers with high mechanical strength (0.84 N tex^?1) and electrical conductivity (1.4 MS m^?1) from the CNT liquid crystal dope with high concentration of CNTs in CSA. The knowledge obtained here may guide development of a way to dissolve extremely long CNTs at high concentration and thereby to enable production of CNT fibers with ultimate properties.     

Preparation of conducting polyacrylonitrile/polypyrrole composite films by electrochemical synthesis and their electrical properties

Electrically conducting polyacrylonitrile (PAN)/polypyrrole (PPy) composite films were prepared by electrochemical polymerization of pyrrole in an insulating PAN matrix under various polymerization conditions and their electrical properties were studied. The conductivities of PAN/PPy composite films peeled off from the platinum electrode he lie in the range of 10^?2–10^?3 s/cm, depending on the preparation conditions: The conductivity increased with the concentrations of the electrolyte and the monomer, but it decreased with the polymerization temperature of pyrrole and the applied potential.     

Wild and hatchery populations of Korean starry flounder (Platichthys stellatus) compared using microsatellite DNA markers

Starry flounder (Platichthys stellatus) is an important sport and food fish found around the margins of the North Pacific. Aquaculture production of this species in Korea has increased because of its commercial value. Microsatellite DNA markers are a useful DNA-based tool for monitoring the genetic variation of starry flounder populations. In this study, 12 polymorphic microsatellite DNA markers were identified from a partial genomic starry flounder DNA library enriched in CA repeats, and used to compare allelic variation between wild and hatchery starry flounder populations in Korea. All loci were readily amplified and demonstrated high allelic diversity, with the number of alleles ranging from 6 to 18 in the wild population and from 2 to 12 in the farmed population. A total of 136 alleles were detected at the 12 microsatellite loci in the two populations. The mean observed and expected heterozygosities were 0.62 and 0.68, respectively, in the hatchery samples and 0.67 and 0.75, respectively, in the wild samples. These results indicate lower genetic variability in the hatchery population as compared to the wild population. Significant shifts in allelic frequencies were detected at eight loci, which resulted in a small but significant genetic differences between the wild and hatchery populations (F(ST) = 0.043, P < 0.05). Further studies with additional starry flounder sample collections are needed for comprehensive determinations of the genetic varieties between the wild and hatchery populations. These microsatellite loci may be valuable for future population genetic studies, monitoring the genetic variation for successful aquaculture management and the preservation of aquatic biodiversity.     

On-line hollow-fiber flow field-flow fractionation-electrospray ionization/time-of-flight mass spectrometry of intact proteins

Capabilities of mass spectrometry for the analysis of intact proteins can be increased through separation methods. Flow field-flow fractionation (FlFFF) is characterized by the particularly "soft" separation mechanism, which is ideally suited to maintain the native structure of intact proteins. This work describes the original on-line coupling between hollow-fiber FlFFF (HF FlFFF), the microcolumn variant of FlFFF, and electrospray ionization/time-of-flight mass spectrometry (ESI/TOFMS) for the analysis and characterization of intact proteins. The results show that the native (or pseudonative) structure of horse heart myoglobin and horseradish peroxidase is maintained. Sample desalting is also observed for horse heart myoglobin. Correlation between the molar mass values independently measured by HF FlFFF retention and ESI/TOFMS allows us to confirm the protein aggregation features of bovine serum albumin and to indicate possible changes in the quaternary structure of human hemoglobin.     

Hollow fiber flow field-flow fractionation of proteins using a microbore channel

Protein separation through hollow fiber flow field-flow fractionation (HF FlFFF) at microflow rate regime was successfully achieved by employing a microbore hollow fiber. In most of the flow field-flow fractionation (FlFFF) techniques applied to the separation of proteins, including hollow fiber FlFFF (HF FlFFF), an outflow rate leading to a detector has typically been a few tenths of a milliliter per minute. In this study, it is demonstrated for the first time that 10 microL/min outflow rate in HF FlFFF can be employed for a successful separation of proteins by utilizing a small inner diameter (450 microm) hollow fiber. Initial evaluations of microbore HF FlFFF separation were made to improve separation efficiency by evaluating plate heights, sample recovery, and the limit of detection using protein standards. Microbore HF FlFFF was applied for the separation of low-abundance blood proteins depleted of high-abundance proteins from raw serum using immunoaffinity chromatography.     

Pinched inlet split flow thin fractionation for continuous particle fractionation: application to marine sediments for size-dependent analysis of PCDD/Fs and metals

It is demonstrated that split-flow thin (SPLITT) fractionation, a continuous separation technique for sorting particles or macromolecules, can be utilized for the fractionation of environmental particles to study a size-dependent analysis of pollutants. In this study, focuses are made on the use of a pinched inlet gravitational SPLITT fractionation, a modified form of SPLITT channel formed by reducing the sample inlet thickness of the channel to improve separation efficiency, to separate marine sediments into five different sizes (<1.0, approximately 1.0 to 2.5, approximately 2.5 to 5.0, approximately 5.0 to 10, and approximately 10 to 53 microm). The resulting size fractions are examined with high resolution gas chromatography/high resolution mass spectrometry to determine the size-dependent distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans along with a statistical data treatment and are analyzed with inductively coupled plasma-atomic emission spectrometry and graphite furnace atomic absorption spectrometry to ascertain its major and trace metals. It is shown that the combined analytical methods detailed in this study can be powerfully utilized in such a way as to analyze pollutant distribution and its concentration with regard to particle sizes for an environmental assessment.     

Design of Magnetic‐Plasmonic Nanoparticle Assemblies via Interface Engineering of Plasmonic Shells for Targeted Cancer Cell Imaging and Separation

Magnetic‐plasmonic nanoparticles have received considerable attention for widespread applications. These nanoparticles (NPs) exhibiting surface‐enhanced Raman scattering (SERS) activities are developed due to their potential in bio‐sensing applicable in non‐destructive and sensitive analysis with target‐specific separation. However, it is challenging to synthesize these NPs that simultaneously exhibit low remanence, maximized magnetic content, plasmonic coverage with abundant hotspots, and structural uniformity. Here, a method that involves the conjugation of a magnetic template with gold seeds via chemical binding and seed‐mediated growth is proposed, with the objective of obtaining plasmonic nanostructures with abundant hotspots on a magnetic template. To obtain a clean surface for directly functionalizing ligands and enhancing the Raman intensity, an additional growth step of gold (Au) and/or silver (Ag) atoms is proposed after modifying the Raman molecules on the as‐prepared magnetic‐plasmonic nanoparticles. Importantly, one‐sided silver growth occurred in an environment where gold facets are blocked by Raman molecules; otherwise, the gold growth is layer‐by‐layer. Moreover, simultaneous reduction by gold and silver ions allowed for the formation of a uniform bimetallic layer. The enhancement factor of the nanoparticles with a bimetallic layer is approximately 10⁷. The SERS probes functionalized cyclic peptides are employed for targeted cancer‐cell imaging and separation.     

Chiral Surface and Geometry of Metal Nanocrystals

Chirality is a basic property of nature and has great importance in photonics, biochemistry, medicine, and catalysis. This importance has led to the emergence of the chiral inorganic nanostructure field in the last two decades, providing opportunities to control the chirality of light and biochemical reactions. While the facile production of 3D nanostructures has remained a major challenge, recent advances in nanocrystal synthesis have provided a new pathway for efficient control of chirality at the nanoscale by transferring molecular chirality to the geometry of nanocrystals. Interestingly, this discovery stems from a purely crystallographic outcome: chirality can be generated on high-Miller-index surfaces, even for highly symmetric metal crystals. This is the starting point herein, with an overview of the scientific history and a summary of the crystallographic definition. With the advance of nanomaterial synthesis technology, high-Miller-index planes can be selectively exposed on metallic nanoparticles. The enantioselective interaction of chiral molecules and high-Miller-index facets can break the mirror symmetry of the metal nanocrystals. Herein, the fundamental principle of chirality evolution is emphasized and it is shown how chiral surfaces can be directly correlated with chiral morphologies, thus serving as a guide for researchers in chiral catalysts, chiral plasmonics, chiral metamaterials, and photonic devices.