Enzymatic Building-Block Synthesis for Solid-Phase Automated Glycan Assembly

Automated chemical oligosaccharide synthesis is an attractive concept that has been successfully applied to a large number of target structures, but requires excess quantities of suitably protected and activated building blocks. Herein we demonstrate the use of biocatalysis to supply such reagents for automated synthesis. By using the promiscuous NmLgtB-B β1-4 galactosyltransferase from Neisseria meningitidis we demonstrate fast and robust access to the LacNAc motif, common to many cell-surface glycans, starting from either lactose or sucrose as glycosyl donors. The enzymatic product was shown to be successfully incorporated as a complete unit into a tetrasaccharide target by automated assembly.     

A Frequency-Selective pH-Responsive paraCEST Agent

Paramagnetic chemical exchange saturation transfer (paraCEST) agents are well-suited for imaging tissue pH because the basis of CEST, chemical exchange, is inherently sensitive to pH. Several previous pH-sensitive paraCEST agents were based on an exchanging Ln³⁺-bound water molecule as the CEST antenna but this design often added additional line-broadening to the bulk water signal due to T₂ exchange. We report herein a pH-sensitive paraCEST agent that lacks an inner-sphere water molecule but contains one Ln-bound −OH group for CEST activation. The Yb³⁺ complex, Yb( 1 ), displayed a single, highly shifted CEST peak originating from the exchangeable Yb-OH proton, the frequency of which changed over the biologically relevant pH range. CEST images of phantoms ranging in pH from 6 to 8 demonstrate the potential of this agent for imaging pH. Initial rodent imaging studies showed that Gd( 1 ) remains in the vascular system much longer than anticipated but is cleared slowly via renal filtration.     

Effect of microcrystalline and microfibrillated cellulose on the evolution of hydration of cement pastes by thermogravimetry

Journal of Thermal Analysis and Calorimetry - The interest in the use of cellulose fibers of increasingly smaller sizes in cementitious materials has increased in recent years. This paper brings...     

Lead Mixed Oxyhalides Satisfying All Fundamental Requirements for High‐Performance Mid‐Infrared Nonlinear Optical Materials

To design high‐performance mid‐infrared (mid‐IR) nonlinear optical (NLO) materials, we have focused on the combination of a heavy metal lone pair cation, Pb²⁺ and mixed oxyhalides. A systematic investigation in PbO‐PbCl₂‐PbBr₂ system led us to discover the first examples of NLO lead mixed oxyhalides, namely, Pb₁₃O₆Cl₄Br₁₀, Pb₁₃O₆Cl₇Br₇, and Pb₁₃O₆Cl₉Br₅. All the reported materials have remarkably comprehensive properties including broad IR transparency (up to 14.0 μm), qualified second harmonic generation (SHG) responses (0.6–0.9×AgGaS₂), wide band gaps (3.05–3.21 eV), and ease of crystal growth. Interestingly, a centimeter‐sized single crystal (2.9×1.3×0.5 cm³) of Pb₁₃O₆Cl₉Br₅ revealing a wide transparent range (0.384–14.0 μm) and high laser damage threshold (LDT) (14.6×AgGaS₂) has been successfully grown in an open system. The study suggests that all the reported mixed oxyhalides are outstanding candidates for mid‐IR NLO materials.     

A Quasilinear System Related with the Asymptotic Equation of the Nematic Liquid Crystal’s Director Field*

In this paper, the author studies the local existence of strong solutions and their possible blow-up in time for a quasilinear system describing the interaction of a short wave induced by an electron field with a long wave representing an extension of the motion of the director field in a nematic liquid crystal’s asymptotic model introduced in [Saxton, R. A., Dynamic instability of the liquid crystal director. In: Current Progress in Hyperbolic Systems (Lindquist, W. B., ed.), Contemp. Math., Vol.100, Amer. Math.Soc., Providence, RI, 1989, pp.325–330] and [Hunter, J. K. and Saxton, R. A., Dynamics of director fields, SIAM J. Appl. Math., 51, 1991, 1498–1521] and studied in [Hunter, J. K. and Zheng, Y., On a nonlinear hyperbolic variational equation I, Arch. Rat. Mech. Anal.,129, 1995, 305–353], [Hunter, J. K. and Zheng, Y., On a nonlinear hyperbolic variational equation II, Arch. Rat. Mech. Anal., 129, 1995, 355–383] and in [Zhang, P. and Zheng,Y., On oscillation of an asymptotic equation of a nonlinear variational wave equation,Asymptotic Anal., 18, 1998, 307–327] and, more recently, in [Bressan, A., Zhang, P. and Zheng, Y., Asymptotic variational wave equations, Arch. Rat. Mech. Anal., 183, 2007,163–185].     

Basic structure–property behavior of UV curable polyurethane acrylates

Effects of hard segment type, soft segment type, soft segment length, and crystallization at various levels of reactive diluent have been studied in polyurethane acrylates. PTMG–IPDI-based PU acrylates gave better soft segment-hard segment phase separation as compared with PTMG–TDI-based ones. Among PTMG–, PCL–, and PTAd–IPDI-based materials, only PTMG-based one gave clean phase separation, and PTAd-based gave the poorest phase separation. With greater phase separation, higher modulus was obtained. Crystallization of soft segment in PTAd–IPDI-based material gave a significant increase in tensile modulus and elongation at break, with a notable difference in dynamic mechanical properties. © 1996 John Wiley & Sons, Inc.     

Computational analysis of the SARS-CoV-2 and other viruses based on the Kolmogorov’s complexity and Shannon’s information theories

Nonlinear Dynamics - This paper tackles the information of 133 RNA viruses available in public databases under the light of several mathematical and computational tools. First, the formal concepts...     

Relevance of gaseous flows in electrochemically assisted soil thermal remediation

Treatment of polluted soil is one of the priorities in the search of a more sustainable planet. Electrochemically assisted soil remediation has been considered a good option for removing organic contaminants contained in soil, including the removal of volatile organic compounds, associated with gaseous streams produced during the treatment. Also, recently, electrochemical gas treatment technologies have been appointed as promising for the treatment of volatile organic compounds. In this work, we review the current opinion about the most recent studies in both areas. The first section focuses on the production of gaseous compounds during soil remediation by conventional and electrochemical systems. The second section describes the recent progress in the integration of adsorption and absorption with electrochemical processes. Finally, we discuss the holistic application of assisted electrochemical technologies in soil remediation, considering also emerging processes recently published in the literature.     

Boosting Hydrogen Evolution at Visible Light Wavelengths by Using a Photocathode with Modal Strong Coupling between Plasmons and a Fabry-Pérot Nanocavity

Hot-hole injection from plasmonic metal nanoparticles to the valence band of p-type semiconductors and reduction by hot electrons should be improved for efficient and tuneable reduction to obtain beneficial chemical compounds. We employed the concept of modal strong coupling between plasmons and a Fabry-Pérot (FP) nanocavity to enhance the hot-hole injection efficiency. We fabricated a photocathode composed of gold nanoparticles (Au−NPs), p-type nickel oxide (NiO), and a platinum film (Pt film) (ANP). The ANP structure absorbs visible light over a broad wavelength range from 500 nm to 850 nm via hybrid modes based on the modal strong coupling between the plasmons of Au−NPs and the FP nanocavity of NiO on a Pt film. All wavelength regions of the hybrid modes of the modal strong coupling system promoted hot-hole injection from the Au−NPs to NiO and proton/water reduction by hot electrons. The incident photon-to-current efficiency based on H₂ evolution through water/proton reduction by hot electrons reached 0.2 % at 650 nm and 0.04 % at 800 nm.