3,059 research outputs found

    Δπ=0 reverse osmosis enriches a high osmotic pressure solution from a low-titre fermentation broth to a saturated solution or salt form using RO and NF membranes

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    Diverse biotechnology products are produced by microbial or eukaryotic cell fermentations in aqueous solutions. Removal of water is inevitable to enrich the product into a concentrated solution or into solid forms (such as crystals). The theoretical minimum energy required to remove 1 m3 of water is 716 kWh for thermal methods and 1 kWh for reverse osmosis (RO). In practice, the thermal methods equipped with heat energy recycling needs about 25 kWh to remove 1 m3 of water, and the RO methods needs about 4 kWh since extra energy (3 kWh) is required to operate pumps and other facilities in a plant. In general, membrane processes need less energy than thermal processes since there is no phase change in the separation processes and do not damage heat-sensitive biotechnology products. While both RO and NF membranes are permeable to water, RO membrane retains NaCl molecules and NF membrane is permeable to NaCl molecules, which is useful to remove inorganic salts from the products. Unlike thermal processes, the application of the membrane processes is limited by high osmotic pressure as the product solution is enriched by removing water. Chang et al. (2013) proposed a concept of osmotic pressure-free reverse osmosis (Δπ=0 RO) that overcomes this limitation and allows concentration of any solution with high osmotic pressure to its saturation point and further to crystal form. Δπ=0 RO, a two-component system, is distinct from 3-component forward osmosis and does not require the third component (draw component or extraction solvent) that must be separated from the aqueous solution at the end. This presentation will compare (1) ways of Δπ=0 RO technologies in desalination, and, furthermore (2) dewatering and desalination of high osmotic solutions of NaCl (343 bar), volatile fatty acids (400 – 600 bar), and fuel ethanol (6000 bar) with thermal separation methods in terms of energy consumption and potential of Δπ=0 RO technology. Chang et al. (2017), US patent 14,764,975(2015, 07,30), registration in progres

    Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations

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    Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M+-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35450−37800 cm^(−1). The lowest-energy band was tentatively assigned to be the origin of the S_0-S_1 transition, and the second band to a vibronic transition arising from the “benzene breathing” mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6. The red shifts of the origin bands were observed in the spectra as the size of the metal cation in M^+-DB18C6 increased from Li^+ to Cs^+. We suggested that these red shifts arose mainly from the decrease in the binding energies of larger-sized metal cations to DB18C6 at the electronic ground state. These size effects of the metal cations on the geometric and electronic structures, and the binding properties of the complexes at the S_0 and S_1 states were further elucidated by theoretical calculations using density functional and time-dependent density functional theories

    BIOFUEL PRODUCTION FROM BIOMASS-DERIVED VOLATILE FATTY ACID PLATFORM

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    The typical biorefinery platforms are sugar, thermochemical (syngas), carbon-rich chains, and biogas platform. The sugar platform uses hexose and pentose sugars extracted or converted from plant body. The thermochemical (syngas) platform is chemical or biological conversion process using pyrolysis or gasification of plant to produce biofuels. The carbon-rich chains platform is used to produce biodiesel from long-chain fatty acids or glycerides. Those platforms have unique advantages and disadvantages. Our group has concentrated on the biogas platform producing methane gas from municipal solid wastes through anaerobic digestion (AD) processs, which is composed of rapid acidogenesis and slow methanogenesis. This acidogenic and methanogenic process is widely used for biogas production form the treatment of wetted waste materials (foodwastes, sludge, and manure) in the worldwide. The volatile fatty acids (VFAs) are short-chain fatty acids composed of mainly acetate and butyrate, and easily produced from non-woody biomass with low lignin content in acidogenesis step by the natural consortia of mixed anaerobic bacteria. And then it is slowly converted to biogas (methane, CO2) by methanogenic bacteria naturally. Now, we would like to suggest a new platform using VFAs for biofuel and biochemicals production, because the VFAs can be produced form a cost-effective way using AD process that does not need sterilization, additional hydrolysis enzymes (cellulase and xylanase) and high cost pretreatment step in case of low-lignin content biomass. Considering that raw material alone constitutes 60-80% of biofuel production costs, biofuels made from the VFAs derived from the waste organic biomass can have a potential of economical advantage. A problem is how to convert VFAs to biofuels and biochemicals. In the presentation, we will give possible solutions in order to produce bioethanol, biobutanol, biodiesel, and biohydrogen as well as biogas through biological or chemical processes. And we will introduce our ongoing researches related with the VFA platfor

    Neutrino propagation in the neutron star with uncertainties from nuclear, hadron, and particle physics

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    In the present work, we investigate the neutral-current neutrino-nucleon scattering in the nuclear medium using various energy-density functional (EDF) models such as the KIDS (Korea-IBS-Daegu-SKKU) and SLy4, together with the quark-meson coupling (QMC) model for the nucleon form factors at finite density. The differential cross section (DCS) and neutrino mean free path (NMFP) are computed numerically, considering the density-dependent nucleon form factors (DDFF) and neutrino structural properties such as the neutrino magnetic moment (NMM) and its electric charge radius (NCR). It turns out that the DDFF decreases the scattering cross-section, while the NCR increases it considerably. The effect of the NMM turns out to be almost negligible. We also observe that the value of the neutron effective mass is of importance in the neutron-star cooling process, indicating that for the neutron effective mass larger than the mass in free space, the neutrino can interact with matter at densities ρ1.5ρ0\rho \gtrsim 1.5 \rho_0 in the neutron star with radius 13 km.Comment: 16 pages, 2 tables, 12 figure

    Effects of Symmetry Energy on the Equation of State for Hybrid Neutron Stars

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    In this paper, the implications of the symmetry energy on the hadron and quark phase transitions in the compact star, including the properties of the possible configurations of the quark-hadron hybrid stars, are investigated in the frameworks of the energy-density functional (EDF) models and the flavor SU(2) Nambu--Jona-Lasinio (NJL) model with the help of the Schwinger's covariant proper-time regularization (PTR) scheme. In this {theoretical setup}, the equations of states (EoSs) of hadronic matter for various values of symmetry energies obtained from the EDF models are employed to describe the hadronic matter, and the {flavor} SU(2) NJL model with various repulsive-vector interaction strengths are used to describe the quark matter. We then observe the obtained EoS in the mass-radius properties of the hybrid star configurations for various vector interactions and nuclear symmetry energies by solving the Tolman-Oppenheimer-Volkoff equation. We obtain that the critical density at which the phase transition occurs varies over the density (3.6--6.7)ρ0\rho_0 depending on the symmetry energy and the strength of the vector coupling GvG_v. The maximum mass of the neutron star (NS) is susceptible to GvG_v. When there is no repulsive force, the NS maximum mass is only about 1.5M1.5M_\odot, but it becomes larger than 2.0M2.0M_\odot when the vector coupling constant is about half of the {attractive} scalar coupling constant. Surprisingly, the presence of the quark matter does not affect the canonical mass of NS (1.4M1.4M_\odot), so observing the canonical mass of NSs can provide unique constraints to the EoS of hadronic matter at high densities.Comment: 20 pages, 5 figures, 1 tabl

    Role of nucleon effective mass and symmetry energy on the neutrino mean free path in neutron star

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    The Korea-IBS-Daegu-SKKU energy density functional (KIDS-EDF) models, derived from the universal Skyrme functional, have been successfully and widely applied in describing the properties of finite nuclei and infinite nuclear matter. In the present work, we extend the applications of the KIDS-EDF models to investigate the implications of the nucleon effective mass and nuclear symmetry energy obtained from the KIDS-EDF models on the properties of neutron star (NS) and neutrino interaction with the NS constituents matter in the linear response approximation (LRA). We then analyze the total differential cross-section of neutrino, neutrino mean free path (NMFP), and the NS mass-radius (M-R) relations. We find that the NS M-R relations predictions for all KIDS-EDF models are in excellent agreement with the recent observations as well as the NICER result. Remarkable prediction results on the NMFPs are given by the KIDS0-m*77 and KIDS0-m*99 models with Mn/M1M_n^* /M \lesssim 1 which are quite higher in comparison with those obtained for the KIDS0, KIDS-A, and KIDS-B models with Mn/M1M_n^*/M \gtrsim 1. For the KIDS0, KIDS-A, and KIDS-B models, we obtain the λRNS\lambda \lesssim R_{\textrm{NS}}, indicating that these models support the slow NS cooling and neutrino trapping in NS. On the contrary, both KIDS0-m*77 and KIDS0-m*99 models support faster NS cooling and a small possibility of neutrino trapping within NS, predicting λRNS\lambda \gtrsim R_{\textrm{NS}}. More interestingly the NMFP decreases as the density and neutrino energy increase, which is consistent with those obtained in the Brussels-Montreal Skyrme (BSk17 and BSk18) models at saturation density.Comment: 24 pages, 2 tables, 22 figure

    Neuroprotective and anti-oxidant effects of caffeic acid isolated from Erigeron annuus leaf

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    <p>Abstract</p> <p>Background</p> <p>Since oxidative stress has been implicated in a neurodegenerative disease such as Alzheimer's disease (AD), natural antioxidants are promising candidates of chemopreventive agents. This study examines antioxidant and neuronal cell protective effects of various fractions of the methanolic extract of <it>Erigeron annuus </it>leaf and identifies active compounds of the extract.</p> <p>Methods</p> <p>Antioxidant activities of the fractions from <it>Erigeron annuus </it>leaf were examined with [2,2-azino-bis(3-ethylbenz thiazoline-6-sulfonic acid diammonium salt)] (ABTS) and ferric reducing antioxidant power (FRAP) assays. Neuroprotective effect of caffeic acid under oxidative stress induced by H<sub>2</sub>O<sub>2 </sub>was investigated with [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) and lactate dehydrogenase (LDH) assays.</p> <p>Results</p> <p>This study demonstrated that butanol fraction had the highest antioxidant activity among all solvent fractions from methanolic extract <it>E. annuus </it>leaf. Butanol fraction had the highest total phenolic contents (396.49 mg of GAE/g). Caffeic acid, an isolated active compound from butanol fraction, showed dose-dependent <it>in vitro </it>antioxidant activity. Moreover, neuronal cell protection against oxidative stress induced cytotoxicity was also demonstrated.</p> <p>Conclusion</p> <p><it>Erigeron annuus </it>leaf extracts containing caffeic acid as an active compound have antioxidative and neuroprotective effects on neuronal cells.</p

    Serially Connected Micro Amorphous Silicon Solar Cells for Compact High-Voltage Sources

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    We demonstrate a compact amorphous silicon (a-Si) solar module to be used as high-voltage power supply. In comparison with the organic solar module, the main advantages of the a-Si solar module are its compatibility with photolithography techniques and relatively high power conversion efficiency. The open circuit voltage of a-Si solar cells can be easily controlled by serially interconnecting a-Si solar cells. Moreover, the a-Si solar module can be easily patterned by photolithography in any desired shapes with high areal densities. Using the photolithographic technique, we fabricate a compact a-Si solar module with noticeable photovoltaic characteristics as compared with the reported values for high-voltage power supplies

    Hypochoeris radicata attenuates LPS-induced inflammation by suppressing P38, ERK, and JNK phosphorylation in Raw 264.7 macrophages

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    Hypochoeris radicata, an invasive plant species, is a large and growing threat to ecosystem integrity on Jeju Island, a UNESCO World Heritage site. Therefore, research into the utilization of H. radicata is important and urgently required in order to solve this invasive plant problem in Jeju Island. The broader aim of our research is to elucidate the biological activities of H. radicata, which would facilitate the conversion of this invasive species into high value added products. The present study was undertaken to identify the pharmacological effects of H. radicata flower on the production of inflammatory mediators in macrophages. The results indicate that the ethyl acetate fraction of H. radicata extract (HRF-EA) inhibited the production of pro-inflammatory molecules such as NO, iNOS, PGE2, and COX-2, and cytokines such as TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 cells. Furthermore, the phosphorylation of MAPKs such as p38, ERK, and JNK was suppressed by HRF-EA in a concentration-dependent manner. In addition, through HPLC and UPLC fingerprinting, luteolins were also identified and quantified as extract constituents. On the basis of these results, we suggest that H. radicata may be considered possible anti-inflammatory candidates for pharmaceutical and/or cosmetic applications

    The Influence of Tibial Positioning on the Diagnostic Accuracy of Combined Posterior Cruciate Ligament and Posterolateral Rotatory Instability of the Knee

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    Background: To determine if tibial positioning affects the external rotation of the tibia in a dial test for posterolateral rotatory instability combined with posterior cruciate ligament (PCL) injuries. Methods: Between April 2007 and October 2007, 16 patients with a PCL tear and posterolateral rotatory instability were diagnosed using a dial test. The thigh-foot angle was measured at both 30 ° and 90 ° of knee fl exion with an external rotation stress applied to the tibia in 2 different positions (reduction and posterior subluxation). The measurements were performed twice by 2 orthopedic surgeons. Results: In posterior subluxation, the mean side-to-side difference in the thigh-foot angle was 11.56 ± 3.01 ° at 30 ° of knee fl exion and 11.88 ± 4.03 ° at 90 ° of knee flexion. In the sequential dial test performed with the tibia reduced, the mean side-to-side difference was 15.94 ± 4.17 ° (p &lt; 0.05) at 30 ° of knee fl exion and 16.88 ± 4.42 ° (p = 0.001) at 90 ° of knee fl exion. The mean tibial external rotation was 5.31 ± 2.86 ° and 6.87 ± 3.59 ° higher in the reduced position than in the posterior subluxation at both 30° and 90 ° of knee fl exion. Conclusions: In the dial test, reducing the tibia with an anterior force increases the ability of an examiner to detect posterolateral rotary instability of the knee combined with PCL injuries
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