Search

The microstructure of ultrathin carbon shells coated on metal nanoparticles is effectively regulated by carbon etching and defect healing effects depending on annealing gas atmospheres.

A carboxymethyl cellulose (CMC)/polyethyleneimine (PEI) hybrid hydrogel was successfully prepared under green processing conditions. The CMC and PEI formed a polyelectrolyte complex, and the three-dimensional (3D) network structure was hardened by chemical crosslinking, resulting in suitable hydrogel properties. In the prepared CMC/PEI polyelectrolyte hydrogel, the surface charge was easily switched according to the pH change, and the resulting swelling and contraction was reversible. The pH sensitivity of the CMC/PEI hydrogel was effective in removing ionic dye contaminants, and as a result, it showed an excellent removal capacity of 319 mg/g for anionic acid orange (AO) and 129 mg/g for cationic methylene blue (MB). In addition, the CMC/PEI polyelectrolyte hydrogel maintained structural stability despite repeated changes in surface charge characteristics and shrinkage-swelling due to repeated pH conversion. As a result, in the reuse process through repeated adsorption and desorption, it showed an excellent reuse efficiency of more than 93% even after 10 reuse cycles.

This study investigated the feature importance of near-infrared spectra from random forest regression models constructed to predict the carbonization characteristics of hydrochars produced by hydrothermal carbonization of kraft lignin. The model achieved high coefficients of determination of 0.989, 0.988, and 0.985 with root mean square errors of 0.254, 0.003, and 0.008 when predicting the carbon content, atomic O/C ratio, and H/C ratio, respectively. The random forest models outperformed the multilayer perceptron models for all predictions. In the feature importance analysis, the spectral regions at 1600–1800 nm, the first overtone of C–H stretching vibrations, and 2000–2300 nm, the combination bands, were highly important for predicting the carbon content and O/C predictions, whereas the region at 1250–1711 nm contributed to predicting H/C. The random forest models trained with the high-importance regions achieved better prediction performances than those trained with the entire spectral range, demonstrating the usefulness of the feature importance yielded by the random forest and the feasibility of selective application of the spectral data.

Aminoacyl-tRNA synthetases (ARSs) have evolved to acquire various additional domains. These domains allow ARSs to communicate with other cellular proteins in order to promote non-translational functions. Vertebrate cytoplasmic isoleucyl-tRNA synthetases (IARS1s) have an uncharacterized unique domain, UNE-I. Here, we present the crystal structure of the chicken IARS1 UNE-I complexed with glutamyl-tRNA synthetase 1 (EARS1). UNE-I consists of tandem ubiquitin regulatory X (UBX) domains that interact with a distinct hairpin loop on EARS1 and protect its neighboring proteins in the multi-synthetase complex from degradation. Phosphomimetic mutation of the two serine residues in the hairpin loop releases IARS1 from the complex. IARS1 interacts with BRCA1 in the nucleus, regulates its stability by inhibiting ubiquitylation via the UBX domains, and controls DNA repair function.

Misinformation about COVID-19 vaccines is widely available in the public communication environment. Exposure to the misinformation may increase perceived risk of and evoke negative emotions toward COVID-19 vaccines that may eventually reduce COVID-19 vaccination intentions. The negative influences of misinformation may vary by aspects of individuals' social networks. Expanding the reasoned action approach, we proposed a comprehensive model to examine the roles of misinformation beliefs, perceived risk, fear, worry, and social networks in explaining COVID-19 vaccination intentions. We tested the model using survey data of South Korean adults, collected when the Korean government launched its nationwide vaccination program in April 2021 (

This paper investigates the moral dimension of English language teaching by analyzing the collaborative reflections of two professional university teachers in Korea. Data were collected from the teacher participants who wrote, shared, and responded to each other’s weekly teaching reflections throughout a 15-week semester. The data were compiled and selectively coded to isolate morality-related content and then analyzed to identify the categories and themes that emerged. Overall, 28.3% of the codes were identified as being associated with the moral dimension of teaching and were divided into three distinct but closely related categories. The category labels are reflective of contradictory discourses in education including (1) Humanization vs. Dehumanization of Students, (2) Alternative vs. Traditional Assessment, and (3) Teacher as Learner vs. Teacher as Knower. The results illustrate that the teachers were frequently conflicted by competing ideologies and draw attention to the need for language teachers to engage in dialogue regarding the value-based decisions which shape their teaching pedagogies.

The development of non−Pt or carbon−based catalysts for anion exchange membrane fuel cells (AEMFCs) requires identification of the active sites of the catalyst. Since not only metals but also carbon materials exhibit oxygen reduction reaction (ORR) activity in alkaline conditions, the contribution of carbon-based materials to ORR performance should also be thoroughly analyzed. However, the conventional CN− poisoning experiments, which are mainly used to explain the main active site of M−N−C catalysts, are limited to only qualitative discussions, having the potential to make fundamental errors. Here, we report a modified electrochemical analysis to quantitatively investigate the contribution of the metal and carbon active sites to ORR currents at a fixed potential by sequentially performing chronoamperometry with two reaction inhibitors, CN− and benzyl trimethylammonium (BTMA+). As a result, we discover how to quantify the individual contributions of two active sites (Pt nanoparticles and carbon support) of carbon−supported Pt (Pt/C) nanoparticles as a model catalyst. This study is expected to provide important clues for the active site analysis of carbon-supported non−Pt catalysts, such as M−N−C catalysts composed of heterogeneous elements.

Because nanocellulose has a large specific surface area and abundant hydroxyl functional groups due to its unique nanomorphology, interest increases as an eco-friendly water treatment material. However, the distinctive properties of nanocellulose, which exists in a dispersion state, strongly hamper its usage in practical water treatment processes. Additionally, nanocellulose shows low performance in removing anionic pollutants because of its anionic characteristics. In an effort to address this challenge, regenerated cellulose (RC) hydrogel was fabricated through cellulose's dissolution and regeneration process using an eco-friendly aqueous solvent system. Subsequently, a crosslinking process was carried out to introduce the cationic functional groups to the RC surface PEI coating (P/RC). As a result, the PEI surface cationization process improved the mechanical rigidity of RC and showed an excellent Cr(VI) removal capacity of 578 mg/g. In addition, the prepared P/RC maintained more than 90% removal efficiency even after seven reuses.

Although nanocellulose is an eco-friendly, high-performance raw material provided by nature, the agglomeration of nanocellulose that occurs during the drying process is the biggest obstacle to its advanced materialization and commercialization. In this study, a facile and simple nanocellulose drying system was designed using lignin, which is self-assembled together with cellulose in natural wood, as an eco-friendly additive. The addition of lignin not only minimized aggregation during the drying and dehydration process of nanocellulose but also ensured excellent redispersion kinetics and stability. In addition, the added lignin could be removed through a simple washing process. Through FTIR, XRD, TGA, tensile and swelling tests, it was confirmed that the addition of lignin enabled the reversible restitution of the nanocellulose physicochemical properties to the level of pristine never-dried nanocellulose in drying, redispersion, and polymer processing processes.

Applications of nanocellulose as a water treatment material are being actively pursued based on its interesting properties, such as renewability, large specific surface area, hydrophilic surface chemistry, and biodegradability. This study used carboxymethyl cellulose nanofibrils (CMCNFs) to prepare a typical bead-type adsorbent with improved structural stability as an actual water treatment restoration material. In addition, a cationized nanocellulose adsorbent was prepared by introducing polyethyleneimine (PEI) on the surface of the CMCNF (P/CMCNF), the removal efficiency of Cr(VI) was evaluated, and its mechanism was elucidated. As a result, the P/CMCNF beads showed an excellent Cr(VI) removal capacity of 1302.3 mg/g, the best result among cellulose-based adsorption materials. Cr(VI) was effectively removed by electrostatic attractions combined with chemical reduction and chelation mechanisms. Furthermore, the macrobead fabrication and PEI surface modification process improved the underwater stability of the P/CMCNF, and it showed excellent reuse efficiency.

A model for the remote sensing of snow water equivalent (SWE) using coherent detection of reflected communication satellite “signals of opportunity” is described in this paper. We modeled the snowpack by a layered medium and compute the phase of specularly reflected signals from the snowpack. Phase change of the reflected signal is predicted to be strongly dependent on SWE for dry snow and on snow depth for wet snow. Phase sensitivity to SWE increases with frequency. Reflected signals with frequencies above S-band, however, will experience rapid phase wrapping (360° change) and become more susceptible to fringe washing due to spatial variability of SWE across the footprint. We also examined the impact of snow grain size, snow density, snow layering, ground surface scattering, and incoherent scattering from ice grains embedded in the snowpack, concluding that these factors do not have a substantial impact on the phase-SWE relationship. However, the snow wetness of more than a few percent can make the reflection from air–snow interface dominant, leading to a correlation between phase change and snow depth. To address the path delay due to the ionosphere, dual-frequency observations would have to be considered. Modeling analysis indicates that the coherent change detection is a promising technique for remote sensing of SWE.

A proof-of-concept experiment was carried out to demonstrate the feasibility of retrieving snow water equivalent (SWE) using P-band signals of opportunity. The fundamental observation is the change in the phase of the reflected waveforms as related to the change in SWE. Through theoretical modeling it was found that the change in SWE was approximately linearly dependent on the change in phase. This was verified by retrieving SWE data collected and processed from a tower-based experiment at Fraser, CO, USA. A linear regression was performed on measured phase and in situ SWE. The correlation was found to be 0.94 and root mean square deviation was found to be 7.5 mm.

Radiation therapy for lung cancer is an effective treatment during monotherapy or combination therapy. Studies have reported that the optimum utilization rate of radiation therapy is estimated at 61% to 74%. Radiation therapy in Korea has been investigated to be low; further studies are needed.This study was intended to assess the appropriateness of the use of radiation and to reveal the use of radiation therapy-related factors by examining radiation therapy in lung cancer patients of Busan and South Gyeongnam Province. This study was aimed at the population diagnosed with lung cancer in Busan and South Gyeongnam Province. To conduct the study, 1036 patients enrolled in two hospitals were collected and 897 appropriate as subjects were selected.We compared the optimum utilization rate and actual rate of radiation therapy, and revealed the adequacy and related factors for use of radiotherapy. Of 897 patients, 503 (56%) were treated with medical therapy and 394 (44%) weregiven radiotherapy.The radiotherapy utilization rate of all lung cancer patients was 42%. The proportion of non-small cell lung cancer by histologic type was 33% and that of small cell lung cancer was 90%. Factors related to radiation therapy used in cancer were age, histological type, clinical stage, doctor refereed to, and clinical examination. Compared to radiation utilization by region (site), curative chest therapy was 42%; palliative treatment was 26%. In the comparison of histologic types, utilization of small-cell lung cancer is lower; the lowest especially in the stage Ⅲ. Utilization of radiation therapy in Busan and South Gyeongnam Province was lower than the reasonable one. Utilization difference could be explained by patient factors, tumor factors, and health service factors. To improve utilization,development ofoutreach service programs and activation of the multidisciplinary team are required.

The National Aeronautics and Space Administration (NASA) in the United States and the Indian Space Research Organisation (ISRO) are developing an Earth-orbiting science and applications mission that will exploit synthetic aperture radar to map Earth's surface every 12 days, persistently on ascending and descending portions of the orbit, over all land and ice-covered surfaces. The mission's primary objectives will be to study Earth land and ice deformation, and ecosystems, in areas of common interest to the US and Indian science communities. This single spacecraft solution with an L-band (24 cm wavelength) and S-band (10 cm wavelength) radar has a swath of over 240 km at fine resolution, using full polarimetry where needed, uses a reflector-feed system whereby the feed aperture elements are individually sampled to allow a scan-on-receive (“SweepSAR”) capability at both L-band and S-band. This design is in contrast to recent concepts towards large constellations of smaller radar satellites, and is driven by the science requirements for complete coverage over the 12-day repeat cycle, using repeat pass interferometry and polarimetry to measure deformation and surface properties. A single spacecraft with enough aperture, power, duty cycle, and downlink capacity was determined to be a more practical and implementable solution that multiple smaller spacecraft. The use of a single large aperture reflector for both the L- and S-band radars enables both to have comparable performance, leading to overall development and operational efficiencies.

Model-based decomposition of polarimetric radar covariance matrices holds the promise that specific scattering mechanisms can be isolated for further quantitative analysis. In this paper, we show that current algorithms suffer from a fatal flaw in that some of the scattering components result in negative powers. We propose a simple modification that ensures that all covariance matrices in the decomposition will have nonnegative eigenvalues. We further combine our nonnegative eigenvalue decomposition with eigenvector decomposition to remove additional assumptions that have to be made before the current algorithms can be used to estimate all the scattering components. Our results are illustrated using Airborne Synthetic Aperture Radar data and show that current algorithms typically overestimate the canopy scattering contribution by 10%-20%.

Previous model-based decomposition techniques are applicable to a limited range of vegetation types because of their specific assumptions about the volume scattering component. Furthermore, most of these techniques use the same model, or just a few models, to characterize the volume scattering component in the decomposition for all pixels in an image. In this paper, we extend the model-based decomposition idea by creating an adaptive model-based decomposition technique, allowing us to estimate both the mean orientation angle and a degree of randomness for the canopy scattering for each pixel in an image. No scattering reflection symmetry assumption is required to determine the volume contribution. We examined the usefulness of the proposed decomposition technique by decomposing the covariance matrix using the National Aeronautics and Space Administration/Jet Propulsion Laboratory Airborne Synthetic Aperture Radar data at the C-, L-, and P-bands. The randomness and mean orientation angle maps generated using our adaptive decomposition significantly improve the physical interpretation of the scattering observed at the three different frequencies.

Current polarimetric model-based decomposition techniques are limited to specific types of vegetation because of their assumptions about the volume scattering component. In this paper, we propose a generalized probability density function based on the nth power of a cosine-squared function. This distribution is completely characterized by two parameters; a mean orientation angle and the power of the cosine-squared function. We show that the underlying randomness of the distribution is only a function of the power of the cosine-squared function. We then derive the average covariance matrix for various different elementary scatterers showing that the result has a very simple analytical form suitable for use in model-based decomposition schemes.

Electromagnetic scattering from a rough surface is a function of both surface roughness and dielectric constant of the scattering surface. Therefore, in order to estimate soil moisture of a bare surface accurately from radar measurements, the effects of surface roughness must be compensated for properly. Several algorithms have been developed to estimate soil moisture from a polarimetric radar image, all with limited ranges of applicability. No theoretical algorithm has been reported to retrieve volumetric soil moisture of a vegetated surface. In this paper, we examine a different approach to estimate soil moisture that exploits the fact that the backscattering cross section from a natural object changes over short timescales mainly due to variations in soil moisture. We develop a model function that expresses copolarized backscattering cross sections (sigmahh and sigmavv) in terms of volumetric soil moisture using L-band experimental data for both bare and vegetated surfaces. In order to estimate soil moisture, two unknowns in the model function must be determined. We propose a viable approach to determine these two unknowns using combined radiometer and radar data. This time-series approach also provides a framework to utilize a priori knowledge on soil moisture to improve the retrieval accuracy of volumetric soil moisture. We demonstrate that this time-series algorithm is a simple and robust way to estimate soil moisture for both bare and vegetated surfaces.

The polarimetric backscattering coefficients (vv-, hh-, hv-, and vh-polarizations) of a flooded rice field are measured using L- and C-band ground-based polarimetric scatterometers. These measurements were made during the rice growth cycle, i.e., from the transplanting period to the harvest period (May to October 2006), to understand the feasibility of modeling and estimating rice growth. We also collected ground truth data that include fresh and dry biomasses, plant height, leaf area index, and leaf size. To study the incidence angle effect, the scatterometer data were collected at four different incidence angles, i.e., 30deg , 40deg, 50deg, and 60deg. In this paper, we show that the backscattering coefficients of a rice field can accurately be modeled using the radiative transfer theory. We also demonstrate that a polarimetric scatterometer is an effective tool for estimating rice growth. The hh-polarized backscattering coefficient is more sensitive to rice growth than its vv-polarization counterpart. The polarimetric ratio can be used to estimate rice growth accurately.

Glycans released from ovalbumin by PNGase F were analyzed by matrix-assisted laser desorption/ionization time-of- flight (MALDI-TOF) mass spectrometry using three different dihydroxybenzoic acid (DHB) matrix systems: 2,5-DHB, 2,6- DHB, and a 2,5-DHB/2,6-DHB binary matrix. Relative to the results obtained with the single-component matrices (2,5-DHB or 2,6-DHB), the 2,5-DHB/2,6-DHB binary matrix boasted lower background noise and higher sensitivity. A total of 16 glycan peaks were observed using the 2,5-DHB/2,6-DHB binary matrix, while only 10 and 9 glycan peaks were observed using the 2,5- DHB and 2,6-DHB matrices, respectively. The current study investigated the effectiveness of a new binary matrix composed of 2,5-DHB and 2,6-DHB in analyses of glycans released from ovalbumin by enzymatic cleavage with PNGase F. The mass spectrum acquired with the binary matrix was compared with those obtained using the single matrix materials (2,5-DHB or 2,6-DHB). Experimental All chemicals were obtained from Sigma-Aldrich (St. Louis, MO, USA) unless otherwise specified. To perform deglyc- osylation, 2 mg of ovalbumin (catalog number: A5503) was mixed with 1 unit of PNGase F (catalog number: P7367) in 200 µL of 50 mM ammonium bicarbonate buffer solution for 2 h at 37 o C with gentle mixing. To prepare the 2,5-DHB/2,6-DHB

The Hydrosphere State Mission (Hydros) is a pathfinder mission in the National Aeronautics and Space Administration (NASA) Earth System Science Pathfinder Program (ESSP). The objective of the mission is to provide exploratory global measurements of the earth's soil moisture at 10-km resolution with two- to three-days revisit and land-surface freeze/thaw conditions at 3-km resolution with one- to two-days revisit. The mission builds on the heritage of ground-based and airborne passive and active low-frequency microwave measurements that have demonstrated and validated the effectiveness of the measurements and associated algorithms for estimating the amount and phase (frozen or thawed) of surface soil moisture. The mission data will enable advances in weather and climate prediction and in mapping processes that link the water, energy, and carbon cycles. The Hydros instrument is a combined radar and radiometer system operating at 1.26 GHz (with VV, HH, and HV polarizations) and 1.41 GHz (with H, V, and U polarizations), respectively. The radar and the radiometer share the aperture of a 6-m antenna with a look-angle of 39/spl deg/ with respect to nadir. The lightweight deployable mesh antenna is rotated at 14.6 rpm to provide a constant look-angle scan across a swath width of 1000 km. The wide swath provides global coverage that meet the revisit requirements. The radiometer measurements allow retrieval of soil moisture in diverse (nonforested) landscapes with a resolution of 40 km. The radar measurements allow the retrieval of soil moisture at relatively high resolution (3 km). The mission includes combined radar/radiometer data products that will use the synergy of the two sensors to deliver enhanced-quality 10-km resolution soil moisture estimates. In this paper, the science requirements and their traceability to the instrument design are outlined. A review of the underlying measurement physics and key instrument performance parameters are also presented.

Recently, there has been increasing interest in the use of spaceborne synthetic aperture radar (SAR) for measuring forest biomass. However, it is noted that conventional SAR using C-band or higher frequencies cannot penetrate into foliage, and therefore the biomass measurements require longer wavelengths, typically P-band (500 MHz). It is also known that the ionosphere is highly dispersive, causing group delay and broadening of pulses. The variance of the refractive index fluctuations due to turbulence is approximately proportional toƒ−4. In addition, the Faraday rotation due to the geomagnetic field in the ionosphere becomes significant. This paper presents an analysis with numerical examples of the following effects in the frequency range from 100 MHz to 2 GHz in order to show the frequency dependence and the effects of total electron content (TEC) of the ionosphere. First, the ionospheric turbulence can reduce the coherent length below the equivalent aperture size, and the azimuthal resolution becomes greater than D/2 where D is the antenna aperture size. Second, the ionospheric dispersion causes a shift of the imagery due to the group velocity. Third, the dispersion also creates broadening of the pulse. In addition, multiple scattering due to ionospheric turbulence gives rise to pulse broadening. Fourth, we consider the Faraday rotation effect and show that the ellipticity change is negligible, but the orientation angle changes significantly at P-band. Numerical examples are shown using typical ionospheric parameters, turbulence spectrum, and TEC values.

Polarimetric SAR decomposition has been used extensively because of its capability to identify the strength of each scattering mechanism from polarimetric SAR data. To achieve higher accuracy, one should take into account not only variation of vegetated terrain but also topography under vegetation. In this paper, we firstly isolate vegetation orientation angle from generalized volume scattering component, and then modify a conventional adaptive model-based decomposition by carefully introducing a concept of topographic polarization orientation compensation (TPOC). Finally, experimental validation is conducted by using P-band AIRSAR image of Black Forest in Germany.

A time-series approach is used to estimate the moisture content based on polarimetric SAR data. It is found that under the assumption of constant soil moisture, empirically observed relationships between radar backscatter and moisture are only half as sensitive to moisture as compared to actual radar data. A numerical finite element method is used to calculate the radar backscatter for rough soils with arbitrarily varying soil moisture as a function of depth. Several instance of drying and wetting moisture profiles are considered and the radar backscatter is calculated in each case. Radar backscatter is found to crucially depend on the soil moisture variation in the top half wavelength of soil.