Block type symmetry of bigraded Toda Hierarchy

In this paper, we define Orlov-Schulman's operators $M_L$, $M_R$, and then use them to construct the additional symmetries of the bigraded Toda hierarchy (BTH). We further show that these additional symmetries form an interesting infinite dimensional Lie algebra known as a Block type Lie algebra, whose structure theory and representation theory have recently received much attention in literature. By acting on two different spaces under the weak W-constraints we find in particular two representations of this Block type Lie algebra.Comment: 30 pages, accepted by Journal of Mathematical Physic

N-Cadherin Expression Level Distinguishes Reserved versus Primed States of Hematopoietic Stem Cells

SummaryOsteoblasts expressing the homophilic adhesion molecule N-cadherin form a hematopoietic stem cell (HSC) niche. Therefore, we examined how N-cadherin expression in HSCs relates to their function. We found that bone marrow (BM) cells highly expressing N-cadherin (N-cadherinhi) are not stem cells, being largely devoid of a Lineage−Sca1+cKit+ population and unable to reconstitute hematopoietic lineages in irradiated recipient mice. Instead, long-term HSCs form distinct populations expressing N-cadherin at intermediate (N-cadherinint) or low (N-cadherinlo) levels. The minority N-cadherinlo population can robustly reconstitute the hematopoietic system, express genes that may prime them to mobilize, and predominate among HSCs mobilized from BM to spleen. The larger N-cadherinint population performs poorly in reconstitution assays when freshly isolated but improves in response to overnight in vitro culture. Their expression profile and lower cell-cycle entry rate suggest N-cadherinint cells are being held in reserve. Thus, differential N-cadherin expression reflects functional distinctions between two HSC subpopulations

Long-Term Protection from SARS-CoV-2 Variants in Mice by a Phase II Clinically Evaluated Original mRNA Vaccine Booster

The global coronavirus disease 2019 (COVID-19) pandemic was caused by SARS-CoV-2. The authors developed an mRNA vaccine (LVRNA009) that encoded the S protein of the Wuhan-Hu-1 strain and evaluated the long-term protection potential against SARS-CoV-2 variants. Mice were initially vaccinated with 2 doses of LVRNA009, then boosted 8 months later. The virus neutralization titers against SARS-CoV-2 variants and antigen-specific T cell responses of the mice were determined. These animals were also tested using viral challenge experiments. Moreover, a phase II clinical study was carried out in 420 healthy adults. LVRNA009 vaccination induced neutralization antibodies and protected mice from SARS-CoV-2 original and Omicron BA.1.1 challenge 8 months post-boosting. A second booster dose of LVRNA009 further enhanced VNTs against Omicron variants. Clinical studies showed that LVRNA009 has good safety and immunogenicity profiles in humans. LVRNA009 could provide long-term protection against SARS-CoV-2 variants and confer better protection with a booster dose. These findings indicate that LVRNA009, a vaccine designed based on the original virus, might be effective in management of the COVID-19 pandemic

Efficient Synthesis of Biobased Furoic Acid from Corncob via Chemoenzymatic Approach

Valorization of lignocellulosic materials into value-added biobased chemicals is attracting increasing attention in the sustainable chemical industry. As an important building block, furoic acid has been commonly utilized to manufacture polymers, flavors, perfumes, bactericides, fungicides, etc. It is generally produced through the selective oxidation of furfural. In this study, we provide the results of the conversion of biomass-based xylose to furoic acid in a chemoenzymatic cascade reaction with the use of a heterogeneous chemocatalyst and a dehydrogenase biocatalyst. For this purpose, NaOH-treated waste shrimp shell was used as a biobased carrier to prepare high activity and thermostability of biobased solid acid catalysts (Sn-DAT-SS) for the dehydration of corncob-valorized xylose into furfural at 170 °C in 30 min. Subsequently, xylose-derived furfural and its derivative furfuryl alcohol were wholly oxidized into furoic acid with whole cells of E. coli HMFOMUT at 30 °C and pH 7.0. The productivity of furoic acid was 0.35 g furoic acid/(g xylan in corncob). This established chemoenzymatic process could be utilized to efficiently valorize biomass into value-added furoic acid

A PE-MUSIC Algorithm for Sparse Array in MIMO Radar

Larger array aperture is provided by sparse arrays than uniform ones, which can improve the angle estimation resolution and reduce the cost of system evidently. However, manifold ambiguity is introduced due to the array sparsity. In this paper, a Power Estimation Multiple-Signal Classification (PE-MUSIC) algorithm is proposed to solve the manifold ambiguity of arbitrary sparse arrays for uncorrelated sources in Multiple-Input Multiple-Output (MIMO) radar. First, the paired direction of departure (DOD) and direction of arrival (DOA) are obtained for all targets by MUSIC algorithm, including the true and spurious ones; then, the well-known Davidon–Fletcher–Powell (DFP) algorithm is applied to estimate all targets’ power values, among which the value of a spurious target trends to zero. Therefore, the ambiguity of sparse array in MIMO radar can be cleared. Simulation results verify the effectiveness and feasibility of the method

Antibacterial Effect of Polyvinyl Alcohol/Biochar–Nano Silver/Sodium Alginate Gel Beads

To date, biochar bacteriostatic material has attracted much attention from researchers. The compact porous structure of fish-scale biochar provides good application prospects. In this study, silver-carrying biochar–polyvinyl alcohol–alginate gel beads (C/PVA/SA) were designed for suppressing bacteria. The biochar was loaded with nano silver particles as the filler, alginate as the substrate, and polyvinyl alcohol (PVA) as the additive to enhance the mechanical properties. The composite gel beads were characterized using Fourier-transform infrared spectrometry (FT-IR). The results indicated that adjusting the PVA concentration could retain the bacteriostatic performance of the gel beads in different pH value solutions. It was found that C/PVA/SA gel beads had a strong inhibitory effect on Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. After ten consecutive antibacterial tests, the antibacterial rate remained high (above 99%) for 15 days. The adhesive effect of SA and PVA resulted in a tight spatial structure of the gel beads. The C/PVA/SA gel composition could effectively prevent water loss and enhance the shrinkage ability of the gel beads. The good degradation performance of C/PVA/SA was also in line with the concept of environmental protection. In general, the C/PVA/SA gel beads showed high potential for application in the treatment of microbial contamination and environmental protection

Sustainable Chemoenzymatic Cascade Transformation of Corncob to Furfuryl Alcohol with Rice Husk-Based Heterogeneous Catalyst UST-Sn-RH

Valorization of the abundant renewable lignocellulose through an efficient chemoenzymatic strategy to produce the furan-based platform compounds has raised great interest in recent years. In this work, a newly prepared sulfonated tin-loaded rice husk-based heterogeneous chemocatalyst UST-Sn-RH was utilized to transform corncob (75.0 g/L) into furfural (72.1 mM) at 170 °C for 30 min in an aqueous system. To upgrade furfural into furfuryl alcohol, whole cells of recombinant E. coli KPADH harboring alcohol dehydrogenase were employed to transform corncob-derived furfural into furfuryl alcohol at 30 °C and pH 7.5. In the established chemoenzymatic cascade process, corncob was efficiently transformed to furfuryl alcohol with a productivity of 0.304 g furfuryl alcohol/(g xylan in corncob). In general, biomass could be efficiently valorized into valuable furan-based chemicals in this tandem reaction with the chemocatalyst (bio-based UST-Sn-RH) and the biocatalyst (KPADH cell) in an aqueous system, which has potential application