Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion

Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat

Daytime radiative cooling using near-black infrared emitters

Recent works have demonstrated that daytime radiative cooling under direct sunlight can be achieved using multilayer thin films designed to emit in the infrared atmospheric transparency window while reflecting visible light. Here, we demonstrate that a polymer-coated fused silica mirror, as a near-ideal blackbody in the mid-infrared and near-ideal reflector in the solar spectrum, achieves radiative cooling below ambient air temperature under direct sunlight (8.2 °C) and at night (8.4 °C). Its performance exceeds that of a multilayer thin film stack fabricated using vacuum deposition methods by nearly 3 °C. Furthermore, we estimate the cooler has an average net cooling power of about 127 Wm^(-2) during daytime at ambient temperature even considering the significant influence of external conduction and convection, more than twice that reported previously. Our work demonstrates that abundant materials and straight-forward fabrication can be used to achieve daytime radiative cooling, advancing applications such as dry cooling of thermal power plants

MApping the Most Massive Overdensities (MAMMOTH) II -- Discovery of an Extremely Massive Overdensity BOSS1441 at z=2.32z=2.32

Cosmological simulations suggest a strong correlation between high optical-depth Ly$\alpha$ absorbers, which arise from the intergalactic medium (IGM), and 3-D mass overdensities on scales of $10-30$ $h^{-1}$ comoving Mpc. By examining the absorption spectra of $\sim$ 80,000 QSO sight-lines over a volume of 0.1 Gpc$^3$ in the Sloan Digital Sky Survey III (SDSS-III), we have identified an extreme overdensity, BOSS1441, which contains a rare group of strong Ly$\alpha$ absorbers at $z=2.32\pm 0.02$. This absorber group is associated with six QSOs at the same redshift on a 30 comoving Mpc scale. Using Mayall/MOSAIC narrowband and broadband imaging, we detect Ly$\alpha$ emitters (LAEs) down to $0.7\times L_{\rm{Ly\alpha}}^*$, and reveal a large-scale structure of Ly$\alpha$ emitters (LAEs) in this field. Our follow-up Large Binocular Telescope (LBT) observations have spectroscopically confirmed 19 galaxies in the density peak. We show that BOSS1441 has an LAE overdensity of $10.8\pm 2.6$ on a 15 comoving Mpc scale which could collapse to a massive cluster with $M\gtrsim10^{15}$ M$_\odot$ at $z\sim0$. This overdensity is among the most massive large-scale structures at $z\sim2$ discovered to date.Comment: 12 pages, 8 figures. submitted to ApJ, Comments are welcom

Changes in the Expression of miR-381 and miR-495 Are Inversely Associated with the Expression of the MDR1 Gene and Development of Multi-Drug Resistance

Multidrug resistance (MDR) frequently develops in cancer patients exposed to chemotherapeutic agents and is usually brought about by over-expression of P-glycoprotein (P-gp) which acts as a drug efflux pump to reduce the intracellular concentration of the drug(s). Thus, inhibiting P-gp expression might assist in overcoming MDR in cancer chemotherapy. MiRNAome profiling using next-generation sequencing identified differentially expressed microRNAs (miRs) between parental K562 cells and MDR K562 cells (K562/ADM) induced by adriamycin treatment. Two miRs, miR-381 and miR-495, that were strongly down-regulated in K562/ADM cells, are validated to target the 3'-UTR of the MDR1 gene. These miRs are located within a miR cluster located at chromosome region 14q32.31, and all miRs in this cluster appear to be down-regulated in K562/ADM cells. Functional analysis indicated that restoring expression of miR-381 or miR-495 in K562/ADM cells was correlated with reduced expression of the MDR1 gene and its protein product, P-gp, and increased drug uptake by the cells. Thus, we have demonstrated that changing the levels of certain miR species modulates the MDR phenotype in leukemia cells, and propose further exploration of the use of miR-based therapies to overcome MDR.The authors would like to declare that we received funding from a commercial source, i.e. Bioplatforms Australia. This does not alter the authors' adherence to all PLOS ONE policies on sharing data and materials

Daytime radiative cooling using near-black infrared emitters

Recent works have demonstrated that daytime radiative cooling under direct sunlight can be achieved using multilayer thin films designed to emit in the infrared atmospheric transparency window while reflecting visible light. Here, we demonstrate that a polymer-coated fused silica mirror, as a near-ideal blackbody in the mid-infrared and near-ideal reflector in the solar spectrum, achieves radiative cooling below ambient air temperature under direct sunlight (8.2 °C) and at night (8.4 °C). Its performance exceeds that of a multilayer thin film stack fabricated using vacuum deposition methods by nearly 3 °C. Furthermore, we estimate the cooler has an average net cooling power of about 127 Wm^(-2) during daytime at ambient temperature even considering the significant influence of external conduction and convection, more than twice that reported previously. Our work demonstrates that abundant materials and straight-forward fabrication can be used to achieve daytime radiative cooling, advancing applications such as dry cooling of thermal power plants

Pt(111)单晶电极上乙二醇解离吸附反应动力学

The dissociative adsorption of ethylene glycol (EG) on Pt (111) electrode has been investigated with electrochemical cyclic voltammetry and programmed potential step technique. The quantitative results demonstrated that the average rate of dissociative adsorption of ethylene glycol on Pt(111) electrode depends on electrode potentials, yielding a distribution of volcanic shape on adsorption potentials between - 0. 20 and 0. 35 V with the maximum value of 3.90 x 10(-12) mol . cm (-2) . s (-1) located near 0. 10 V ( vs SCE). From the variation of the quanti-ty of dissociative adsorbates determined through the oxidation charge with adsorption time ( t(ad)), the initial rate ( nu(i)) of this surface reaction has been evaluated quantitatively. The maximum of nu(i) was ascertained to be 4.35 x 10 (-12) mol . cm (-2) - s (-1) at 0. 10 V for a solution containing 2 x 10 (-3) mol . L (-1) EG

The Late Stage of COPI Vesicle Fission Requires Shorter Forms of Phosphatidic Acid and Diacylglycerol

Studies on vesicle formation by the Coat Protein I (COPI) complex have contributed to a basic understanding of how vesicular transport is initiated. Phosphatidic acid (PA) and diacylglycerol (DAG) have been found previously to be required for the fission stage of COPI vesicle formation. Here, we find that PA with varying lipid geometry can all promote early fission, but only PA with shortened acyl chains promotes late fission. Moreover, diacylglycerol (DAG) acts after PA in late fission, with this role of DAG also requiring shorter acyl chains. Further highlighting the importance of the short-chain lipid geometry for late fission, we find that shorter forms of PA and DAG promote the vesiculation ability of COPI fission factors. These findings advance a general understanding of how lipid geometry contributes to membrane deformation for vesicle fission, and also how proteins and lipids coordinate their actions in driving this process

The late stage of COPI vesicle fission requires shorter forms of phosphatidic acid and diacylglycerol

Studies on vesicle formation by the Coat Protein I (COPI) complex have contributed to a basic understanding of how vesicular transport is initiated. Phosphatidic acid (PA) and diacylglycerol (DAG) have been found previously to be required for the fission stage of COPI vesicle formation. Here, we find that PA with varying lipid geometry can all promote early fission, but only PA with shortened acyl chains promotes late fission. Moreover, diacylglycerol (DAG) acts after PA in late fission, with this role of DAG also requiring shorter acyl chains. Further highlighting the importance of the short-chain lipid geometry for late fission, we find that shorter forms of PA and DAG promote the vesiculation ability of COPI fission factors. These findings advance a general understanding of how lipid geometry contributes to membrane deformation for vesicle fission, and also how proteins and lipids coordinate their actions in driving this process