Recent Advances in the Development of Mincle-Targeting Vaccine Adjuvants.

The Macrophage-inducible C-type lectin (Mincle) is a pattern-recognition receptor (PRR), which has shown much promise as a molecular target for the development of T1/T17-skewing vaccine adjuvants. In 2009, the first non-proteinaceous Mincle ligands, trehalose dimycolate (TDM) and trehalose dibehenate (TDB), were identified. This prompted a search for other Mincle agonists and the exploration of Mincle agonists as vaccine adjuvants for both preventative and therapeutic (anti-cancer) vaccines.

Four-electron reduction of benzene by a samarium(II)-alkyl without the addition of external reducing agents.

Benzene reduction by molecular complexes remains an important synthetic challenge, requiring harsh reaction conditions involving group I metals. Reductions of benzene, to date, typically result in a loss of aromaticity, although the benzene tetra-anion, a 10π-electron system, has been calculated to be stable and aromatic. Due to the lack of sufficiently potent reductants, four-electron reduction of benzene usually requires the use of group I metals.

Surface-enhanced Raman spectroscopy: a half-century historical perspective.

Surface-enhanced Raman spectroscopy (SERS) has evolved significantly over fifty years into a powerful analytical technique. This review aims to achieve five main goals. (1) Providing a comprehensive history of SERS's discovery, its experimental and theoretical foundations, its connections to advances in nanoscience and plasmonics, and highlighting collective contributions of key pioneers.

Natural and Semisynthetic Immunomodulatory Luakuliide Labdane Diterpenoids.

Spectroscopy-guided isolation of extracts of the Tongan marine sponge cf. (Lamarck, 1814) has resulted in the reisolation of the labdane diterpenoid luakuliide A () and one new congener, luakulialactam A (). In addition to establishing the absolute configuration of , synthetic modifications to the luakuliide framework at key positions has created a set of six derivatives (-) which were used to interrogate a structure-activity relationship relating to the immunomodulatory effects of luakuliide A.

Synthesis of -Glycoside Building Blocks as Mimetics of the Repeating d-GlcN-α-1,4-d-GlcA Heparan Sulfate Disaccharide.

Heparan sulfate (HS), a sulfated linear carbohydrate that decorates the cell surface and extracellular matrix, is a key regulator of biological processes. Owing to the inherent structural complexity of HS, structure-to-function studies with its ligands are required, and materials to improve the understanding of such interactions are therefore of high importance. Herein, the synthesis of novel -linked GlcN-α(1→4)-GlcA disaccharide building blocks is detailed.

Excitonic Dark States in Molecular Monolayer Crystals.

The tightly bound excitons and strong dipole-dipole interactions in two-dimensional molecular crystals enable rich physics. Among them, superradiance (SR), the spontaneous coherent emission from bright excitons, has sparked considerable interest in quantum-information applications. In addition, optically forbidden states (dark exciton states) have potential to both achieve Bose-Einstein condensation and modulate exciton dynamics.

Synthesis, Structural, and Raman Investigation of Lanthanide Nitride Powders ( = La, Ce, Nd, Sm, Gd, Tb, Dy, Er, Lu).

Lanthanide nitride (N) materials have garnered significant interest in recent years due to their promising potential as heterogeneous catalysts for green ammonia synthesis under low temperature and pressure reaction conditions. Here, we report on the synthesis of an extended series of lanthanide () nitride powders ( = lanthanum, cerium, neodymium, samarium, gadolinium, terbium, dysprosium, erbium, lutetium) and their structural and vibrational properties. Polycrystalline powders were fabricated using a ball milling mechanochemical process, and their structural properties were assessed by X-ray diffraction (XRD) and transmission electron microscopy (TEM).

Spin polarisation and non-isotropic effective mass in the conduction band of GdN.

GdN is a ferromagnetic semiconductor which has seen increasing interest in the preceding decades particularly in the areas of spin- and superconducting- based electronics. Here we report a detailed computational and optical spectroscopy study of the electronic structure of stoichiometric and nitrogen vacancy doped GdN. Based on our calculations we provide the effective mass tensor for undoped GdN, and some indicative values for electron doped GdN.

Physio-Metabolic Mechanisms Behind Postharvest Quality Deterioration in Broccoli ( var. Italica) and Swiss Chard ( L. var. Cicla): A Review.

Leafy vegetables are among the potential foods that can combat food insecurity in developing countries. Their major drawback is a short shelf life, which limits their supply chain and is commonly associated with their high metabolic activities. Leafy vegetables have a high water content, which determines their freshness.

Synthesis of Nucleoside Analogs Containing Sulfur or Selenium Replacements of the Ribose Ring Oxygen or Carbon.

Nucleoside analogs have proven highly successful in many pharmaceutical intervention strategies, and continued exploration of next generation structural motifs is required. Herein we discuss recent advances toward the chemical synthesis of heteroatom-modified nucleosides, where this is constituted by the chalcogens sulfur or selenium. Paying specific focus to the organic chemistry to incorporate these heteroatoms, we consider developments toward ribose ring oxygen and ring carbon replacements alongside chalcogen-modified heterobases.

Frustrated Lewis Pairs from Al-E Bonds (E=Ge, Sn, Pb).

The potassium aluminyl K[Al(NON)] ([NON]=[O(SiMeNDipp)], Dipp=2,6-iPrCH) reacts with group 14 chloroamidinates E(Am)Cl (E=Ge, Sn, Pb. [Am]=[tBuC(NDipp)]) to form (NON)Al-E(Am) Lewis pairs with unsupported Al-E bonds, including the first structurally authenticated Al-Pb bond. Analysis using spectroscopic (NMR, UV-vis and Mössbauer for E=Sn), X-ray diffraction and computational (DFT, QTAIM, TD-DFT) methods conclude an Al-E σ-bond derived from a Lewis basic Al and a Lewis acidic tetrylene, with back-donation from the E s-orbital lone pair donor NBO to acceptor NBOs on Al that are derived from s/p-orbitals.

Shallow defects and optical properties of CsPbBrthin films through noble gas ion beam defect engineering.

Ion implantation is widely utilised for the modification of inorganic semiconductors; however, the technique has not been extensively applied to lead halide perovskites. In this report, we demonstrate the modification of the optical properties of caesium lead bromide (CsPbBr) thin films via noble gas ion implantation. We observed that the photoluminescence (PL) lifetimes of CsPbBrthin films can be doubled by low fluences (<1 × 10at·cm) of ion implantation with an acceleration voltage of 20 keV.

Single-Entity Electrochemistry of N-Doped Graphene Oxide Nanostructures for Improved Kinetics of Vanadyl Oxidation.

N-doped graphene oxides (GO) are nanomaterials of interest as building blocks for 3D electrode architectures for vanadium redox flow battery applications. N- and O-functionalities have been reported to increase charge transfer rates for vanadium redox couples. However, GO synthesis typically yields heterogeneous nanomaterials, making it challenging to understand whether the electrochemical activity of conventional GO electrodes results from a sub-population of GO entities or sub-domains.

Delivery of carbon dioxide to an electrode surface using a nanopipette.

We have developed a new scanning probe approach for the delivery of a gas-phase reactant to the surface of an electrocatalyst through a self-replenishing bubble located at the end of a scanning probe. This approach enables local electrocatalytic rates to be detected under very-high mass transport rates due to the small distance between the gas-phase reactant in the bubble and the electrocatalyst surface. Here we report experiments for the delivery of carbon dioxide to a gold ultramicroelectrode surface using a micron-scale nanopipette.

Histidine-bridged cyclic peptide natural products: isolation, biosynthesis and synthetic studies.

The histidine bridge is a rare and often overlooked structural motif in macrocyclic peptide natural products, yet there are several examples in nature of cyclic peptides bearing this moiety that exhibit potent biological activity. These interesting compounds have been the focus of several studies reporting their isolation, biosynthesis and chemical synthesis over the last four decades. This review summarises the findings on the structure, biological activity and, where possible, proposed biosynthesis and progress towards the synthesis of histidine-bridged cyclic peptides.

Towards the synthesis of a 2-deoxy-2-fluoro-d-mannose building block and characterisation of an unusual 2-S-phenyl anomeric pyridinium triflate salt via 1 → 2 S-migration.

Regio- and stereo-selective synthetic routes to 2-deoxy-2-fluoro-d-mannose building blocks are often experimentally challenging when using Selectfluor with the corresponding glycal. We targeted a late-stage method to introduce fluorine in a stereospecific manner using inversion via a triflate. Accordingly, synthesis of a conventionally protected 2-deoxy-2-fluoro-d-mannose β-thioglycoside donor, directly applicable to oligosaccharide synthesis, was attempted using C2-triflate inversion of the corresponding d-glucoside with TBAF.

Sugar-Coated: Can Multivalent Glycoconjugates Improve upon Nature's Design?

Multivalent interactions between receptors and glycans play an important role in many different biological processes, including pathogen infection, self-recognition, and the immune response. The growth in the number of tools and techniques toward the assembly of multivalent glycoconjugates means it is possible to create synthetic systems that more and more closely resemble the diversity and complexity we observe in nature. In this Perspective we present the background to the recognition and binding enabled by multivalent interactions in nature, and discuss the strategies used to construct synthetic glycoconjugate equivalents.

CO Loss into Solution: An Experimental Investigation of CO Electrolysis with a Membrane Electrode Assembly Cell.

In pursuit of commercial viability for carbon dioxide (CO) electrolysis, this study investigates the operational challenges associated with membrane electrode assembly (MEA)-type CO electrolyzers, with a focus on CO loss into the solution phase through bicarbonate (HCO ) and carbonate (CO ) ion formation. Utilizing a silver electrode known for selectively facilitating CO to CO conversion, the molar production of CO, CO, and H is measured across a range of current densities from 0 to 600 mA/cm, while maintaining a constant CO inlet flow rate of 58 mL/min. The dynamics of CO loss are monitored through measurements of pH changes in the electrolyte and carbon elemental balance analysis.

Separation and concentration of CO from air using a humidity-driven molten-carbonate membrane.

Separation processes are substantially more difficult when the species to be separated is highly dilute. To perform any dilute separation, thermodynamic and kinetic limitations must be overcome. Here we report a molten-carbonate membrane that can 'pump' CO from a 400 ppm input stream (representative of air) to an output stream with a higher concentration of CO, by exploiting ambient energy in the form of a humidity difference.

Detection of nitro-aromatics using CN as an electrochemical sensor: a DFT approach.

Nitroaromatics impose severe health problems and threats to the environment. Therefore, the detection of such hazardous substances is essential to save the whole ecosystem. Herein, the CN sheet is used as an electrochemical sensor for the detection of 1,3-dinitrobenzene (1,3-DNB), trinitrotoluene (TNT), and picric acid (PA) using the PBE0/def2SVP level of theory as implemented in Gaussian 16.

Stimulated Emission and Lasing from Bulk CdSe Nanocrystals.

Nanocrystals with a size in the regime of vanishing quantum confinement, or bulk nanocrystals (BNCs), have emerged recently as viable solution processable optical gain materials in the green part of the spectrum. Here, we show that these properties can be extended to the crucial red region using CdSe BNCs. Through quantitative time-resolved spectroscopy, we can model these nanocrystals as bulk semiconductors, thereby revealing that the gain originates from an unbound electron-hole plasma state.

Benzoylation of Tetrols: A Comparison of Regioselectivity Patterns for and Glycosides of d-Galactose.

Efficient protecting group strategies are important for glycan synthesis and represent a unique synthetic challenge in differentiating sugar ring hydroxyl groups. Direct methods to enable regioselective protecting group installation are thus desirable. Herein, we explore a one-step regioselective benzoylation to deliver 2,3,6-protected d-galactose building blocks from tetrols across a variety of α- and β-, - and -glycoside substrates.