Chiral Se Nanobrooms with Wavelength and Polarization Sensitive Scattering

High-index dielectric nanostructures offer strong magnetic and electric resonances in the visible range and low optical losses, stimulating research interest in their use for light manipulation technologies. Lithographic fabrication of dielectric nanostructures, while providing precise control over the pattern dimensions, limits the scalability of this approach for practical applications due to an inefficient fabrication process and limited production quantity. Here, the colloidal synthesis of high-index chiral dielectric nanostructures with a broom-like geometry made from trigonal Se is demonstrated. The anisotropic morphology and crystal structure of Se nanobrooms enable both linearly and circularly polarized scattering, as well as spectrum variation along the particle axis, which is, to the authors’ knowledge, the first observation of such behavior from dielectric colloidal nanostructures. To show the versatility of the highly scattering Se NB suspensions, 2D and 3D printing of Se NB inks are demonstrated as a proof of concept. This approach provides a way to manipulate light using aqueous dispersions of high-index dielectric nanostructures, unlocking their potential to fit in various morphologies and dimensions in 2D and 3D for broad applications.     

Using mass spectrometry to study copper-protein binding under native and non-native conditions: beta-2-microglobulin

A method based on metal-catalyzed oxidation (MCO) reactions and mass spectrometry (MS) has been used to determine the Cu(II) binding sites in both native and unfolded conformations of beta-2-microglobulin (beta2m). Recent studies have shown that beta2m is destabilized and can form amyloid fibers in the presence of Cu(II). An increased affinity for Cu in unfolded states compared to that of the native state is suspected to facilitate overall protein destabilization. Cu-binding site information for native beta2m is difficult to obtain using traditional techniques because of its propensity to form amyloid fibers at relatively high protein concentrations in the presence of Cu and because of the nonspecific paramagnetic peak broadening observed in NMR analyses. In addition, Cu-binding information of unfolded beta2m is complicated by the high concentrations of denaturants (e.g., 8 M urea) needed to ensure protein unfolding. The MCO/MS approach has been successfully employed in this work to overcome these difficulties. The sensitivity of MS allowed the Cu-binding site of the native protein to be determined at the low concentrations of beta2m necessary to avoid amyloid fiber formation. Results indicate that the N-terminus of the protein and His31 are responsible for Cu(II) coordination in the native state. The MCO/MS method was also successful at determining the Cu-binding site in the presence of 8 M urea with the N-terminus, His31, His51, and His81 found to be Cu-bound in the unfolded state. This result supports the existence of a well-defined but different coordination structure in the unfolded state, which leads to the greater affinity for Cu(II) observed in the unfolded state of the protein. In general, it appears that the MCO/MS method is capable of providing Cu-binding site information for proteins that are difficult to study by traditional means.     

Analysis of NHEJ-Based DNA Repair after CRISPR-Mediated DNA Cleavage

Genome editing using CRISPR-Cas9 nucleases is based on the repair of the DNA double-strand break (DSB). In eukaryotic cells, DSBs are rejoined through homology-directed repair (HDR), non-homologous end joining (NHEJ) or microhomology-mediated end joining (MMEJ) pathways. Among these, it is thought that the NHEJ pathway is dominant and occurs throughout a cell cycle. NHEJ-based DSB repair is known to be error-prone; however, there are few studies that delve into it deeply in endogenous genes. Here, we quantify the degree of NHEJ-based DSB repair accuracy (termed NHEJ accuracy) in human-originated cells by incorporating exogenous DNA oligonucleotides. Through an analysis of joined sequences between the exogenous DNA and the endogenous target after DSBs occur, we determined that the average value of NHEJ accuracy is approximately 75% in maximum in HEK 293T cells. In a deep analysis, we found that NHEJ accuracy is sequence-dependent and the value at the DSB end proximal to a protospacer adjacent motif (PAM) is relatively lower than that at the DSB end distal to the PAM. In addition, we observed a negative correlation between the insertion mutation ratio and the degree of NHEJ accuracy. Our findings would broaden the understanding of Cas9-mediated genome editing.     

Nanorod-assembled spinel Li1.05Mn1.95O4 rods with a central tunnel along the rod-axis for high rate capability of rechargeable lithium-ion batteries

Nanorod-assembled spinel Li_1.05Mn_1.95O₄ rods with a central tunnel along the rod-axis were synthesized using highly crystalline β-MnO₂ rods as self-templates. The synthesized spinel Li_1.05Mn_1.95O₄ is an assembly of several single crystal-like nanorods with an average diameter and length of 100 and 400 nm, respectively, which was determined by microstructural Rietveld refinement using the synchrotron powder XRD data. Galvanostatic battery testing showed that central-tunneled and nanorod-assembled Li_1.05Mn_1.95O₄ rods have a high charge storage capacity at high current densities in comparison with those of the spinel rods without a tunnel structure and commercial powders. Moreover, a capacity retention value of ∼81% was observed at the end of 100 cycles at a current of 250 mAh g⁻¹.     

Novel preparation and high electrical performance effect of Mn-doped ultra-high surface area activated carbon (USAC) as an additive for Ni hybrid capacitors

This paper reports the synthesis of various molar concentrations of manganese (Mn)-doped Ultra-High Surface area Activated Carbon (USAC) additives and their efficient use as cathode materials for supercapacitors. We synthesized the nanoparticles via a novel and facile dip-coating process and characterized them in detail by various analytical techniques. The SEM, EDAX, and XPS results showed that the Mn ions were successfully substituted on the USAC additives’ layered structure without any structural changes. The long cyclic stability of the as-prepared Mn-doped USAC additives was tested as a cathode material for supercapacitors at different current densities. The detailed experimental results showed that the Mn dopant content crucially determines the electrochemical performances of the USAC additives. Electrochemical measurements showed that the MnCEP-S600HTT with 0.10 mol% molar concentration of Mn dopant gives the best cycling performances. It delivers a discharge capacity of 262.9 mAh g^?1 after 100 cycles. Further increasing the current density to 1000 mA g^?1 allowed it to still maintain 253.6 mAh g^?1 after 200 cycles. We confirmed that the structure of Mn-doped USAC additives is an important pole to improve the structural stability and electrochemical properties.     

A precise position measurement system of roll-to-roll printing using burst alignment patterns

Microsystem Technologies - Printed electronics involve a process of creating electrical devices by printing with conductive ink on flexible substrates. This process is environmentally-friendly and...     

Random permutation Maxout transform for cancellable facial template protection

In this paper, we propose a salting based two-factor cancelable biometrics construct, dubbed Random Permutation Maxout (RPM) transform for facial template protection. The RPM transform is inspired from a member of rank-based Locality Sensitive Hashing (LSH), namely Winner Takes All hashing, which was devised for data retrieval. With externally generated user-specific parameters, RPM converts a continuous facial feature vector into a max ranked indices vector as cancellable template. Since the features magnitude of facial features have been transformed to the discrete index form, the resulting template is robust against noises and it is strongly concealed from the adversary learning on the original facial features. This lays a strong promise on non-invertibility requirement The LSH theory compliance RPM is shown minimal performance deterioration after transform. The experimental results render reasonable accuracy performance on benchmark AR and FERET datasets. We also perform several rigorous security, privacy, revocability and unlinkability analyses, which are required for cancellable biometrics techniques.     

Synthesis and characterization of integrated layered nanocomposites for lithium ion batteries

The series of Li[Ni _x M _x Li_1/3-x Mn_2/3-x ]O₂ cathodes, where M is cobalt or chromium with a wide compositional range x from 0 to 0.33, were prepared by hydroxide coprecipitation method with subsequent quenching. The sample structures were investigated using X-ray diffraction results which were indexed completely on the basis of a trigonal structure of space group with monoclinic C2/m phase as expected. The morphologies and electrochemical properties of the samples obtained were compared as the value of x and substituted transition metal. The particle sizes of cobalt-substituted Li[Ni _x Co _x Li_1/3-x Mn_2/3-x ]O₂ samples are much smaller than those of the Li[Ni _x Cr _x Li_1/3-x Mn_2/3-x ]O₂ system. The electrode containing Li[Ni _x Co _x Li_1/3-x Mn_2/3-x ]O₂ with x = 0.10 delivered a discharge capacity of above 200 mAh/g after 10 cycles due to the activation of Li₂MnO₃.     

Identification and Characterization of PSEUDO-RESPONSE REGULATOR (PRR) 1a and 1b Genes by CRISPR/Cas9-Targeted Mutagenesis in Chinese Cabbage (Brassica rapa L.)

The CRISPR/Cas9 site-directed gene-editing system offers great advantages for identifying gene function and crop improvement. The circadian clock measures and conveys day length information to control rhythmic hypocotyl growth in photoperiodic conditions, to achieve optimal fitness, but operates through largely unknown mechanisms. Here, we generated core circadian clock evening components, Brassica rapa PSEUDO-RESPONSE REGULATOR (BrPRR) 1a, 1b, and 1ab (both 1a and 1b double knockout) mutants, using CRISPR/Cas9 genome editing in Chinese cabbage, where 9–16 genetic edited lines of each mutant were obtained. The targeted deep sequencing showed that each mutant had 2–4 different mutation types at the target sites in the BrPRR1a and BrPRR1b genes. To identify the functions of BrPRR1a and 1b genes, hypocotyl length, and mRNA and protein levels of core circadian clock morning components, BrCCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) and BrLHY (LATE ELONGATED HYPOCOTYL) a and b were examined under light/dark cycles and continuous light conditions. The BrPRR1a and 1ab double mutants showed longer hypocotyls, lower core circadian clock morning component mRNA and protein levels, and a shorter circadian rhythm than wildtype (WT). On the other hand, the BrPRR1b mutant was not significantly different from WT. These results suggested that two paralogous genes may not be associated with the same regulatory function in Chinese cabbage. Taken together, our results demonstrated that CRISPR/Cas9 is an efficient tool for achieving targeted genome modifications and elucidating the biological functions of circadian clock genes in B. rapa, for both breeding and improvement.     

A model to predict long-term performance of vapor-phase bioreactors: a cellular automaton approach

A novel numerical model was constructed to predict performance of vapor-phase bioreactors (VPBs) operated over extended periods. This model incorporates two unique features to simulate changes in pollutant removal efficiency and biomass accumulation: (1) total biomass is divided into two microbial components, active and inactive biomass, and (2) biomass growth and biofilm thickness changes are simulated by means of a cellular automaton (CA) approach. The CA approach, a differential-discrete algorithm, numerically allows the excess quantity of biomass in each numerical element to move toward the biofilm surface as biomass accumulates. One set of experimental bioreactor data was used to estimate unknown model parameters. A 90-day simulation using the estimated parameters agreed with pollutant removal and biomass accumulation profiles determined experimentally. Four additional model simulations using the same estimated model parameters were generally consistent with experimental data collected from a series of toluene-degrading VPBs operated over a range of conditions. Model predictions imply that the decline in bioreactor performance observed over extended operation was caused by a decline in the active biomass fraction and a decrease in the biofilm specific surface area. This CA model provides insight into biomass accumulation during complex bioreactor operation and improves our capability to predict long-term VPB performance.