Conversion of low-grade waste heat into electricity is an important energy harvesting strategy. However, abundant heat from these low-grade thermal streams cannot be harvested readily because of the ...absence of efficient, inexpensive devices that can convert the waste heat into electricity. Here we fabricate carbon nanotube aerogel-based thermo-electrochemical cells, which are potentially low-cost and relatively high-efficiency materials for this application. When normalized to the cell cross-sectional area, a maximum power output of 6.6 W m(-2) is obtained for a 51 °C inter-electrode temperature difference, with a Carnot-relative efficiency of 3.95%. The importance of electrode purity, engineered porosity and catalytic surfaces in enhancing the thermocell performance is demonstrated.
The basolateral protein Scribble (Scrib), a member of the LAP protein family, is essential for epithelial apicobasal polarity (ABP) in
However, a conserved function for this protein in mammals is ...unclear. Here we show that the crucial role for Scrib in ABP has remained obscure due to the compensatory function of two other LAP proteins, Erbin and Lano. A combined Scrib/Erbin/Lano knockout disorganizes the cell-cell junctions and the cytoskeleton. It also results in mislocalization of several apical (Par6, aPKC, and Pals1) and basolateral (Llgl1 and Llgl2) identity proteins. These defects can be rescued by the conserved "LU" region of these LAP proteins. Structure-function analysis of this region determined that the so-called LAPSDb domain is essential for basolateral targeting of these proteins, while the LAPSDa domain is essential for supporting the membrane basolateral identity and binding to Llgl. In contrast to the key role in
, mislocalization of Llgl proteins does not appear to be critical in the
ABP phenotype.
We show that surface plasmons, excited with femtosecond laser pulses on continuous or discontinuous gold substrates, strongly enhance the generation and emission of ultrashort, broadband terahertz ...pulses from single layer graphene. Without surface plasmon excitation, for graphene on glass, ‘nonresonant laser-pulse-induced photon drag currents’ appear to be responsible for the relatively weak emission of both s- and p-polarized terahertz pulses. For graphene on a discontinuous layer of gold, only the emission of the p-polarized terahertz electric field is enhanced, whereas the s-polarized component remains largely unaffected, suggesting the presence of an additional terahertz generation mechanism. We argue that in the latter case, ‘surface-plasmon-enhanced optical rectification’, made possible by the lack of inversion symmetry at the graphene on gold surface, is responsible for the strongly enhanced emission. The enhancement occurs because the electric field of surface plasmons is localized and enhanced where the graphene is located: at the surface of the metal. We believe that our results point the way to small, thin, and more efficient terahertz photonic devices.
Adherens junctions (AJs) play a fundamental role in tissue integrity; however, the organization and dynamics of the key AJ transmembrane protein, E-cadherin, both inside and outside of AJs, remain ...controversial. Here we have studied the distribution and motility of E-cadherin in punctate AJs (pAJs) of A431 cells. Using single-molecule localization microscopy, we show that pAJs in these cells reach more than 1 μm in length and consist of several cadherin clusters with crystal-like density interspersed within sparser cadherin regions. Notably, extrajunctional cadherin appears to be monomeric, and its density is almost four orders of magnitude less than observed in the pAJ regions. Two alternative strategies of tracking cadherin motion within individual junctions show that pAJs undergo actin-dependent rapid—on the order of seconds—internal reorganizations, during which dense clusters disassemble and their cadherins are immediately reused for new clusters. Our results thus modify the classical view of AJs by depicting them as mosaics of cadherin clusters, the short lifetimes of which enable stable overall morphology combined with rapid internal rearrangements.
Research on the development of a superconducting power cable for commercialization is currently underway across the world. Many demonstrations of superconducting power cables connected to real power ...grids have already been conducted with various designs depending on the voltage levels of the distribution and transmission lines. In Korea, the first commercial project for high temperature superconducting (HTS) power cables, "Shingal Project" which is fully funded by Korea Electric Power Corporation (KEPCO), is underway to connect two substations with a 23 kV HTS cable with a distance of 1 km. In addition, the KEPCO Research Center (KEPRI) initiated the project in 2017 to develop the 23-kV tri-axial HTS power cables, including a cooling system, for a distance of 3 km. In this paper, the recent progress and research activities related to the two 23-kV superconducting power cables projects are discussed. An economic evaluation of the HTS power cables for commercialization in consideration of their construction environments and social issues is also presented.
Oral squamous cell carcinoma (OSCC) is a highly malignant tumor that is frequently associated with lymph node metastasis, resulting in poor prognosis and survival in patients. In the tumor ...microenvironment, hypoxia plays an important role in regulating cellular responses such as progressive and rapid growth and metastasis. In these processes, tumor cells autonomously undergo diverse transitions and acquire functions. However, hypoxia-induced transition of OSCC and the involvement of hypoxia in OSCC metastasis remain unclear. Therefore, in this study, we aimed to elucidate the mechanism of hypoxia-induced OSCC metastasis and particularly, its impact on tight junctions (TJs).
The expression of hypoxia-inducible factor 1-alpha (HIF-1α) was detected in tumor tissues and adjacent normal tissues from 29 patients with OSCC using reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry (IHC). The migration and invasion abilities of OSCC cell lines treated with small interfering (si)RNA targeting HIF-1α or cultured in hypoxic conditions were analyzed using Transwell assays. The effect of HIF-1α expression on in vivo tumor metastasis of OSCC cells was evaluated using lung metastasis model.
HIF-1α was overexpressed in patients with OSCC. OSCC metastasis was correlated with HIF-1α expression in OSCC tissues. Hypoxia increased the migration and invasion abilities of OSCC cell lines by regulating the expression and localization of partitioning-defective protein 3 (Par3) and TJs. Furthermore, HIF-1α silencing effectively decreased the invasion and migration abilities of OSCC cell lines and restored TJ expression and localization via Par3. The expression of HIF-1α was positively regulated the OSCC metastasis in vivo.
Hypoxia promotes OSCC metastasis by regulating the expression and localization of Par3 and TJ proteins. HIF-1α positively correlates to OSCC metastasis. Lastly, HIF-1α expression could regulate the expression of Par3 and TJs in OSCC. This finding may aid in elucidating the molecular mechanisms of OSCC metastasis and progression and developing new diagnostic and therapeutic approaches for OSCC metastasis.
Various types of actuation methods for microrobots have been proposed. Among the actuation methods, electromagnetic based actuation (EMA) has been considered a promising actuation mechanism. In this ...paper, a new EMA system for three-dimensional (3D) locomotion and drilling of the microrobot is proposed. The proposed system consists of four fixed coil pairs and one rotating coil pair. In detail, the coil system has three pairs of stationary Helmholtz coil, a pair of stationary Maxwell coil and a pair of rotating Maxwell coil. The Helmholtz coil pairs can magnetize and align the microrobot to the desired direction and the two pairs of Maxwell coil can generate the propulsion force of the microrobot. In addition, the Helmholtz coil pairs can rotate the microrobot about a desired axis. The rotation of the microrobot is a drilling action through an occlusion in a vessel. Through various experiments, the 3D locomotion and drilling of the microrobot by using the proposed EMA system are demonstrated. Compared with other EMA systems, the proposed system can provide the advantages of consecutive locomotion and drilling of the microrobot.
Abstract
Background
Rapid metastasis of oral squamous cell carcinoma (OSCC) is associated with a poor prognosis and a high mortality rate. However, the molecular mechanisms underlying OSCC metastasis ...have not been fully elucidated. Although deregulated expression of microRNA (miRNA) has a crucial role in malignant cancer progression, the biological function of miRNA in OSCC progression remains unclear. This study aimed to investigate the function of miRNA-18a in OSCC metastatic regulation via hypoxia-inducible factor 1α (HIF-1α).
Methods
miRNA-18a-5p (miRNA-18a) expressions in patients with OSCC (n = 39) and in OSCC cell lines (e.g., YD-10B and HSC-2 cells) were analyzed using quantitative real-time polymerase chain reaction. HIF-1α protein expressions in OSCC cells treated with miRNA-18a mimics or combined with cobalt chloride were analyzed using western blotting. The miRNA-18a expression-dependent proliferation and invasion abilities of OSCC cells were analyzed using MTT assay, EdU assay, and a Transwell® insert system.
Results
miRNA-18a expression was significantly lower in OSCC tissue than in the adjacent normal tissue. In OSCC cell lines, HIF-1α expression was significantly decreased by miRNA-18a mimic treatment. Furthermore, the migration and invasion abilities of OSCC cells were significantly decreased by miRNA-18a mimics and significantly increased by the overexpression of HIF-1α under hypoxic conditions relative to those abilities in cells treated only with miRNA-18a mimics.
Conclusions
miRNA-18a negatively affects HIF-1α expression and inhibits the metastasis of OSCC, thereby suggesting its potential as a therapeutic target for antimetastatic strategies in OSCC.
Although astaxanthin has promising physiological functions, its practical applications are limited by poor stability. Herein, astaxanthin was encapsulated in β-cyclodextrin (βCD) using CO2 as a ...supercritical antisolvent (SAS). The effects of process conditions, including temperature (313–333 K), pressure (12–18 MPa), solution concentration (3–5 wt%), solution flow rate (0.8–1.2 mL min−1), and astaxanthin-to-βCD mole ratio (1:50, 1:25, or 1:10), on the encapsulation efficiency, particle morphology, and residual solvent content were investigated. Astaxanthin–βCD complex spheres with an average diameter of 0.44 ± 0.08 µm were produced at 313 K and 15 MPa with a solution concentration and flow rate of 5 wt%, and 1.0 mL min−1, respectively. Under these optimal conditions, almost complete encapsulation (99.6% encapsulation efficiency) and residual organic solvent removal (0.22 ppm in the complex) were achieved. Density functional theory analysis of the configuration of the astaxanthin–βCD complex indicate that the hydroxyl hydrogen atoms on an ionone ring of astaxanthin interact with the oxygen atoms of βCD, but the ionone ring does not fit deeply within the βCD cavity. Notably, the astaxanthin–βCD complex exhibits higher thermal stability and antioxidant activity than free astaxanthin. The findings suggest that βCD encapsulation via the SAS process can produce astaxanthin microparticles with potential utility for food and pharmaceutical applications.
•Astaxanthin encapsulation in β-cyclodextrin was achieved using scCO2 as antisolvent.•Supercritical antisolvent (SAS) process produced amorphous microparticles.•Encapsulation efficiency of 99.6% with very low residual DMSO content was achieved.•Encapsulated particles exhibited enhanced thermal stability and antioxidant activity.•Inclusion complex was validated in the molecular level.
Supercoil Company Ltd. has commercialized a 300-k W-high-Tc-based superconducting induction heater (SIH). Supercoil has many patents related to the SIH as well as technologies to maintain thermal ...stability and reliability in the operation of a high-Tc superconducting magnet against uneven quench through the metal insulation winding method. Here, two high-temperature superconducting (HTS) magnets were installed with the two iron cores. The configuration of the 300-kW SIH was introduced. The heating simulation results of the various metal billets were shown through the temperature distribution of the billet. Operating results of the HTS magnets, such as the terminal voltages, excitation current, magnetic flux density, and magnet temperature, are presented and shown. Through these results, metal industries gain access to SIH reference information.
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