Latest Articles

Open AccessArticle
Seasonal Changes in the Tetrodotoxin Content of the Flatworm Planocera multitentaculata
Mar. Drugs 2017, 15(3), 56; doi:10.3390/md15030056 (registering DOI) -
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin that acts specifically on voltage-gated sodium channels on excitable membranes of muscle and nerve tissues. The biosynthetic process for TTX is unclear, although marine bacteria are generally thought to be the primary producers. The marine flatworm Planocera
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Tetrodotoxin (TTX) is a potent neurotoxin that acts specifically on voltage-gated sodium channels on excitable membranes of muscle and nerve tissues. The biosynthetic process for TTX is unclear, although marine bacteria are generally thought to be the primary producers. The marine flatworm Planocera multitentaculata is a known TTX-bearing organism, and is suspected to be a TTX supplier to pufferfish. In this study, flatworm specimens were collected from an intertidal zone in Hayama, Kanagawa, Japan, the TTX content of the flatworm was measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS), and seasonal changes in TTX content were investigated. No significant difference in TTX concentration of the flatworm body was found between the spawning period and other periods. However, the TTX content in individual flatworms was significantly higher in the spawning period than at other times. The TTX content rose in association with an increase in the body weight of the flatworm. Full article
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Open AccessArticle
Study of the Spatiotemporal Characteristics of Meltwater Contribution to the Total Runoff in the Upper Changjiang River Basin
Water 2017, 9(3), 165; doi:10.3390/w9030165 (registering DOI) -
Abstract
Melt runoff (MR) contributes significantly to the total runoff in many river basins. Knowledge of the meltwater contribution (MCR, defined as the ratio of MR to the total runoff) to the total runoff benefits water resource management and flood control. A process-based land
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Melt runoff (MR) contributes significantly to the total runoff in many river basins. Knowledge of the meltwater contribution (MCR, defined as the ratio of MR to the total runoff) to the total runoff benefits water resource management and flood control. A process-based land surface model, Noah-MP, was used to investigate the spatiotemporal characteristics of MR and MCR in the Upper Changjiang River (as known as Yangtze River) Basin (UCRB) located in southwestern China. The model was first calibrated and validated using snow cover fraction (SCF), runoff, and evapotranspiration (ET) data. The calibrated model was then used to perform two numerical experiments from 1981 to 2010: control experiment that considers MR and an alternative experiment that MR is removed. The difference between two experiments was used to quantify MR and MCR. The results show that in the entire UCRB, MCR was approximately 2.0% during the study period; however, MCR exhibited notable spatiotemporal variability. Four sub-regions over the Qinghai-Tibet Plateau (QTP) showed significant annual MCR ranging from 3.9% to 6.0%, while two sub-regions in the low plain regions showed negligible annual MCR. The spatial distribution of MCR was generally consistent with the distribution of glaciers and elevation distribution. Mann-Kendall (M-K) tests of the long-term annual MCR indicated that the four sub-regions in QTP exhibited increasing trends ranging from 0.01%/year to 0.21%/year during the study period but only one displayed statistically significant trend. No trends were found for the peak time (PT) of MR and MCR, in contrast, advancing trend were observed for the center time (CT) of MR, ranging from 0.01 months/year to 0.02 months/year. These trends are related to the changes of air temperature and precipitation in the study area. Full article
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Open AccessArticle
Tuberatolide B Suppresses Cancer Progression by Promoting ROS-Mediated Inhibition of STAT3 Signaling
Mar. Drugs 2017, 15(3), 55; doi:10.3390/md15030055 (registering DOI) -
Abstract
Tuberatolide B (TTB, C27H34O4) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast,
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Tuberatolide B (TTB, C27H34O4) is a diastereomeric meroterpenoid isolated from the Korean marine algae Sargassum macrocarpum. However, the anticancer effects of TTB remain unknown. In this study, we demonstrate that TTB inhibits tumor growth in breast, lung, colon, prostate, and cervical cancer cells. To examine the mechanism by which TTB suppresses cell growth, we determined the effect of TTB on apoptosis, ROS generation, DNA damage, and signal transduction. TTB induced ROS production in MDA-MB-231, A549, and HCT116 cells. Moreover, TTB enhanced DNA damage by inducing γH2AX foci formation and the phosphorylation of DNA damage-related proteins such as Chk2 and H2AX. Furthermore, TTB selectively inhibited STAT3 activation, which resulted in a reduction in cyclin D1, MMP-9, survivin, VEGF, and IL-6. In addition, TTB-induced ROS generation caused STAT3 inhibition, DNA damage, and apoptotic cell death. Therefore, TTB suppresses cancer progression by promoting ROS-mediated inhibition of STAT3 signaling, suggesting that TTB is useful for the treatment of cancer. Full article
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Open AccessCommunication
Antioxidant Activity of SOD and Catalase Conjugated with Nanocrystalline Ceria
Bioengineering 2017, 4(1), 18; doi:10.3390/bioengineering4010018 (registering DOI) -
Abstract
Interactions of nanoparticles with biological matter—both somatically and in nature—draw scientists’ attention. Nanoparticulate systems are believed to be our saviors, acting as versatile drug delivery vehicles. However, they can also cause life-threatening bodily damage. One of the most important properties of nanocrystalline cerium
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Interactions of nanoparticles with biological matter—both somatically and in nature—draw scientists’ attention. Nanoparticulate systems are believed to be our saviors, acting as versatile drug delivery vehicles. However, they can also cause life-threatening bodily damage. One of the most important properties of nanocrystalline cerium dioxide is its antioxidant activity, which decreases the abundance of reactive oxygen species during inflammation. In this paper, we report on synergistic effects of inorganic cerium oxide (IV) nanoparticles conjugated with the antioxidative enzymes superoxide dismutase and catalase on scavenging oxygen and nitrogen radicals. Full article
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Open AccessArticle
Dense Descriptors for Optical Flow Estimation: A Comparative Study
J. Imaging 2017, 3(1), 12; doi:10.3390/jimaging3010012 (registering DOI) -
Abstract
Estimating the displacements of intensity patterns between sequential frames is a very well-studied problem, which is usually referred to as optical flow estimation. The first assumption among many of the methods in the field is the brightness constancy during movements of pixels between
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Estimating the displacements of intensity patterns between sequential frames is a very well-studied problem, which is usually referred to as optical flow estimation. The first assumption among many of the methods in the field is the brightness constancy during movements of pixels between frames. This assumption is proven to be not true in general, and therefore, the use of photometric invariant constraints has been studied in the past. One other solution can be sought by use of structural descriptors rather than pixels for estimating the optical flow. Unlike sparse feature detection/description techniques and since the problem of optical flow estimation tries to find a dense flow field, a dense structural representation of individual pixels and their neighbors is computed and then used for matching and optical flow estimation. Here, a comparative study is carried out by extending the framework of SIFT-flow to include more dense descriptors, and comprehensive comparisons are given. Overall, the work can be considered as a baseline for stimulating more interest in the use of dense descriptors for optical flow estimation. Full article
Open AccessArticle
Towards a Landmark-Based Pedestrian Navigation Service Using OSM Data
ISPRS Int. J. Geo-Inf. 2017, 6(3), 64; doi:10.3390/ijgi6030064 (registering DOI) -
Abstract
With the advent of location-aware smartphones, the desire for pedestrian-based navigation services has increased. Unlike car-based services where instructions generally are comprised of distance and road names, pedestrian instructions should instead focus on the delivery of landmarks to aid in navigation. OpenStreetMap (OSM)
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With the advent of location-aware smartphones, the desire for pedestrian-based navigation services has increased. Unlike car-based services where instructions generally are comprised of distance and road names, pedestrian instructions should instead focus on the delivery of landmarks to aid in navigation. OpenStreetMap (OSM) contains a vast amount of geospatial information that can be tapped into for identifying these landmark features. This paper presents a prototype navigation service that extracts landmarks suitable for navigation instructions from the OSM dataset based on several metrics. This is coupled with a short comparison of landmark availability within OSM, differences in routes between locations with different levels of OSM completeness and a short evaluation of the suitability of the landmarks provided by the prototype. Landmark extraction is performed on a server-side service, with the instructions being delivered to a pedestrian navigation application running on an Android mobile device. Full article
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Open AccessArticle
Mechanical, Swelling, and Structural Properties of Mechanically Tough Clay-Sodium Polyacrylate Blend Hydrogels
Gels 2017, 3(1), 10; doi:10.3390/gels3010010 (registering DOI) -
Abstract
We investigated the mechanical, swelling, and structural properties of mechanically tough clay/sodium polyacrylate (PAAS) hydrogels prepared by simple mixing. The gels had large swelling ratios, reflecting the characteristics of the constituent polymer. The swelling ratios initially increased with the increase of the swelling
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We investigated the mechanical, swelling, and structural properties of mechanically tough clay/sodium polyacrylate (PAAS) hydrogels prepared by simple mixing. The gels had large swelling ratios, reflecting the characteristics of the constituent polymer. The swelling ratios initially increased with the increase of the swelling time, and then attained maximum values. Afterwards, they decreased with an increase of the swelling time and finally became constant. An increase in the clay concentration lead to a decrease in the swelling ratios, whereas an increase in the PAAS concentration lead to an increase in the swelling ratios. Tensile measurements indicated that the toughness for clay/PAAS (Mw = 3.50 × 106) gels was several hundred times larger than that of clay/PAAS (Mw = 5.07 × 105) gels, i.e., the use of ultra-high molecular weight PAAS is essential for fabricating mechanically tough clay/PAAS blend hydrogels. Synchrotron small-angle X-ray scattering (SAXS) results showed that the SAXS intensity measured at small scattering angles decreased with an increase in the clay concentration, indicating that the interparticle interactions were more repulsive at higher concentrations. The decrease of the scattering intensity at high clay concentrations was larger for the clay/PAAS (Mw = 5.07 × 105) gel system than for the clay/PAAS (Mw = 3.50 × 106) gel system. Full article
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Open AccessReview
MYC in Regulating Immunity: Metabolism and Beyond
Genes 2017, 8(3), 88; doi:10.3390/genes8030088 (registering DOI) -
Abstract
Myelocytomatosis oncogene (MYC) family members, including cellular MYC (c-Myc), neuroblastoma derived MYC (MYCN), and lung carcinoma derived MYC (MYCL), have all been implicated as key oncogenic drivers in a broad range of human cancers. Beyond cancer, MYC plays an important role in other
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Myelocytomatosis oncogene (MYC) family members, including cellular MYC (c-Myc), neuroblastoma derived MYC (MYCN), and lung carcinoma derived MYC (MYCL), have all been implicated as key oncogenic drivers in a broad range of human cancers. Beyond cancer, MYC plays an important role in other physiological and pathological processes, namely immunity and immunological diseases. MYC largely functions as a transcription factor that promotes the expression of numerous target genes to coordinate death, proliferation, and metabolism at the cellular, tissue, and organismal levels. It has been shown that the expression of MYC family members is tightly regulated in immune cells during development or upon immune stimulations. Emerging evidence suggests that MYC family members play essential roles in regulating the development, differentiation and activation of immune cells. Through driving the expression of a broad range of metabolic genes in immune cells, MYC family members coordinate metabolic programs to support immune functions. Here, we discuss our understanding of MYC biology in immune system and how modulation of MYC impacts immune metabolism and responses. Full article
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Open AccessArticle
In-Built Customised Mechanical Failure of 316L Components Fabricated Using Selective Laser Melting
Technologies 2017, 5(1), 9; doi:10.3390/technologies5010009 (registering DOI) -
Abstract
The layer-by-layer building methodology used within the powder bed process of Selective Laser Melting facilitates control over the degree of melting achieved at every layer. This control can be used to manipulate levels of porosity within each layer, effecting resultant mechanical properties. If
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The layer-by-layer building methodology used within the powder bed process of Selective Laser Melting facilitates control over the degree of melting achieved at every layer. This control can be used to manipulate levels of porosity within each layer, effecting resultant mechanical properties. If specifically controlled, it has the potential to enable customisation of mechanical properties or design of in-built locations of mechanical fracture through strategic void placement across a component, enabling accurate location specific predictions of mechanical failure for fail-safe applications. This investigation examined the process parameter effects on porosity formation and mechanical properties of 316L samples whilst maintaining a constant laser energy density without manipulation of sample geometry. In order to understand the effects of customisation on mechanical properties, samples were manufactured with in-built porosity of up to 3% spanning across ~1.7% of a samples’ cross-section using a specially developed set of “hybrid” processing parameters. Through strategic placement of porous sections within samples, exact fracture location could be predicted. When mechanically loaded, these customised samples exhibited only ~2% reduction in yield strength compared to samples processed using single set parameters. As expected, microscopic analysis revealed that mechanical performance was closely tied to porosity variations in samples, with little or no variation in microstructure observed through parameter variation. The results indicate that there is potential to use SLM for customising mechanical performance over the cross-section of a component. Full article

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