Nanoporosity development in the thermal-shock KOH activation of brown coal

Thermal-shock KOH activation of brown coal (800 °C, KOH/coal ratio 1 g/g) was shown to produce nanoporous activated carbon with more developed surface area than thermally-programmed heating (S_BET up to 1700 vs 1000 m²/g). Increasing the KOH/coal ratio (up to 1 g/g) in the activated mixture increases the total pore volume (0.14–1.0 cm³/g), the micropore volume (0.03–0.71 cm³/g), and also the volume of subnanometer pores (0.01–0.40 cm³/g). Thermal shock produces nanoporosity at lower KOH/coal ratios (0.5-1.0 g/g) than respective low-rate heating KOH activation.     

Derivatization of Mirror-Image l-Nucleic Acids with 2′-OMe Modification for Thermal and Structural Stabilization

To further expand the functionality and enhance the stability of mirror-image nucleic acids as advanced agents for basic research and therapeutic design, we have synthesized 2′-deoxy-2′-methoxy-l -uridine phosphoramidite and incorporated it into l -DNA and l -RNA by solid-phase synthesis quantitatively. We found that the thermostability of l -nucleic acids is dramatically improved after introducing the modifications. Moreover, we successfully crystallized both l -DNA and l -RNA duplexes containing the 2′-OMe modifications and sharing identical sequences. Crystal structure determination and analysis revealed the overall structures of the mirror-image nucleic acids, and for the first time it was possible to interpret the structural deviations caused by 2′-OMe and 2′-OH groups in the oligonucleotides, which are very similar. This novel chemical nucleic acid modification has the potential to be used to design nucleic acid-based therapeutics and materials in the future.     

Ethylbenzene formation and its conversion towards coke in the side-chain methylation of toluene on a basic X zeolite

Journal of Porous Materials - Side-chain alkylation of toluene with methanol was realized on a strongly basic X-type zeolite which does not contain Brønsted acid sites under short contact time...     

Numerical investigation on a laser based localised joining with a glass frit intermediate layer

Localised laser bonding using a glass frit intermediate layer is an ideal technology to hermetically package miniature devices without heating the function components. In this paper, we investigated from a device level packaging perspective, the influence of the laser ring diameter and width, copper boss (heat sink) diameter and misalignment of laser ring in a laser based localised bonding with glass frit intermediate layer. The conclusions are: (1) laser ring diameter and width have slight influence on the bonding process however a system with smaller laser ring diameters achieves better performance compared to that with larger ring diameters. (2) The copper boss (heat sink) diameter has significant influence on the laser power level required to achieve a particular glass frit curing temperature within the glass frit ring. Selection of an appropriate copper boss diameter is determined by the maximum allowable temperature for the temperature-sensitive devices under protection. (3) Misalignment of the laser ring has significant influence on the localised laser bonding and the recommended misalignment deviation for the laser ring should be less than 100 μm.     

Differentiation of CO isotopic variants by frequency tuning a terahertz source

The transmission spectra of two CO isotopic variants, i.e., (12)CO and (13)CO, are measured with a recently developed widely tunable THz source. The pure rotational transition lines of J=6 --> 7, 10 --> 11, 11 --> 12, 12 --> 13, and 13 --> 14 have been identified in the spectra. The transition frequencies and the rotational constant of each CO isotopic variant are also presented. Experimental results indicate that the difference of the rotational constants between the two isotopic variants can be used to reliably differentiate (12)CO and (13)CO. Compared with the measurements made by using a Fourier transform infrared spectrometer, our tunable THz source has produced approximately the same accuracies for measuring transition frequencies or determining rotational constants.     

LSSmScarlet,dCyRFP2s,dCyOFP2s and CRISPRed2s,Genetically Encoded Red Fluorescent Proteins with a Large Stokes Shift

Genetically encoded red fluorescent proteins with a large Stokes shift (LSSRFPs) can be efficiently co-excited with common green FPs both under single- and two-photon microscopy, thus enabling dual-color imaging using a single laser. Recent progress in protein development resulted in a great variety of novel LSSRFPs; however, the selection of the right LSSRFP for a given application is hampered by the lack of a side-by-side comparison of the LSSRFPs’ performance. In this study, we employed rational design and random mutagenesis to convert conventional bright RFP mScarlet into LSSRFP, called LSSmScarlet, characterized by excitation/emission maxima at 470/598 nm. In addition, we utilized the previously reported LSSRFPs mCyRFP1, CyOFP1, and mCRISPRed as templates for directed molecular evolution to develop their optimized versions, called dCyRFP2s, dCyOFP2s and CRISPRed2s. We performed a quantitative assessment of the developed LSSRFPs and their precursors in vitro on purified proteins and compared their brightness at 488 nm excitation in the mammalian cells. The monomeric LSSmScarlet protein was successfully utilized for the confocal imaging of the structural proteins in live mammalian cells and multicolor confocal imaging in conjugation with other FPs. LSSmScarlet was successfully applied for dual-color two-photon imaging in live mammalian cells. We also solved the X-ray structure of the LSSmScarlet protein at the resolution of 1.4 Å that revealed a hydrogen bond network supporting excited-state proton transfer (ESPT). Quantum mechanics/molecular mechanics molecular dynamic simulations confirmed the ESPT mechanism of a large Stokes shift. Structure-guided mutagenesis revealed the role of R198 residue in ESPT that allowed us to generate a variant with improved pH stability. Finally, we showed that LSSmScarlet protein is not appropriate for STED microscopy as a consequence of LSSRed-to-Red photoconversion with high-power 775 nm depletion light.     

A boundary integral method for a dynamic, transient mode I crack problem with viscoelastic cohesive zone

We consider the problem of the dynamic, transient propagation of a semi-infinite, mode I crack in an infinite elastic body with a nonlinear, viscoelastic cohesize zone. Our problem formulation includes boundary conditions that preclude crack face interpenetration, in contrast to the usual mode I boundary conditions that assume all unloaded crack faces are stress-free. The nonlinear viscoelastic cohesive zone behavior is motivated by dynamic fracture in brittle polymers in which crack propagation is preceeded by significant crazing in a thin region surrounding the crack tip. We present a combined analytical/numerical solution method that involves reducing the problem to a Dirichlet-to-Neumann map along the crack face plane, resulting in a differo-integral equation relating the displacement and stress along the crack faces and within the cohesive zone.     

Comparative Genomics of Seasonal Senescence in Forest Trees

In the course of evolution, both flowering plants and some gymnosperms have developed such an adaptation to winter and unfavorable living conditions as deciduousness. Of particular interest is Siberian larch (Larix sibirica Ledeb.), which is the only species in the pine family (Pinaceae) with a seasonal deciduousness. New generation sequencing technologies make it possible to study this phenomenon at the genomic level and to reveal the genetic mechanisms of leaf and needle aging in angiosperms and gymnosperms. Using a comparative analysis of the genomes of evergreen and deciduous trees, it was found that the genes that control EXORDIUM LIKE 2 (EXL2) and DORMANCY-ASSOCIATED PROTEIN 1 (DRM1) proteins are most represented in Siberian larch, while an excess of genes that control proteins acting as immune receptors were found in evergreens. Orthologs from the family of genes that control leucine-rich repeat receptor-like kinases (LRR-RLK) contributed mostly to the distinction between evergreens and deciduous plants.     

The Search for Associations of Serum Proteins with the Presence of Unstable Atherosclerotic Plaque in Coronary Atherosclerosis

To study the associations of blood proteins with the presence of unstable atherosclerotic plaques in the arteries of patients with coronary atherosclerosis using quantitative proteomics. The studies involved two groups of men with coronary atherosclerosis (group 1 (St) had only stable atherosclerotic plaques; group 2 (Ns) had only unstable atherosclerotic plaques, according to histological analysis of tissue samples); the average age of patients was 57.95 ± 7.22. Protein concentrations in serum samples were determined using the PeptiQuant Plus Proteomics Kit. The identification of protein fractions was carried out by monitoring multiple reactions on a Q-TRAP 6500 mass spectrometer combined with a liquid chromatograph. Mass spectrometric identification revealed in serum samples from patients with unstable atherosclerotic plaques a reduced concentration of proteins in the blood: α-1-acid glycoprotein, α-1-antichymotrypsin, α-1-antitrypsin, ceruloplasmin, hemopexin, haptoglobin, apolipoprotein B-100, apolipoprotein L1, afamin and complement component (C3, C7, C9). Moreover, at the same time a high concentration complements factor H and attractin. The differences were considered significant at p < 0.05. It was found that the instability of atherosclerotic plaques is associated with the concentration of proteins: afamin, attractin, components of the complement system, hemopexin and haptoglobin. The data of our study showed the association of some blood proteins with the instability of atherosclerotic plaques in coronary atherosclerosis. Their potential role in the development of this disease and the possibility of using the studied proteins as biomarkers requires further research.