Cloud-Enabled Handheld NIR Spectroscopy: A Transformative Approach for Real-Time Forensic Analysis of Cannabis Specimens

In the past few years, there has been significant interest within the forensic community regarding the deployment of portable solutions that provide real-time results. This article introduces an innovative technology or technology architecture that enables the integration of a handheld device, specifically, Viavi MicroNIR, with a cloud-based system. This cloud system encompasses a server responsible for data processing and a mobile application acting as a user interface. To demonstrate the transformative impact of this technology on field operators, the analysis of cannabis specimens has been utilized. System's capacity to distinguish between CBD-type and THC-type cannabis has been particularly highlighted, along with the remarkable congruence observed between the near-infrared (NIR) spectra and the reference analytical method involving ultra-high-performance liquid chromatography (UHPLC) The article will present the advantages of this application primarily focusing on its potential to alleviate the burden on laboratories by expediting routine illicit drug analysis. Viavi MicroNIR technology provides laboratory personnel with additional time to handle more complex cases, thereby enhancing overall efficiency.     

Fine Pore-Structure Engineering by Ligand Conformational Control of Naphthalene Diimide-Based Semiconducting Porous Coordination Polymers for Efficient Chemiresistive Gas Sensing

Exploring new porous coordination polymers (PCPs) that have tunable structure and conductivity is attractive but remains challenging. Herein, fine pore structure engineering by ligand conformation control of naphthalene diimide (NDI)-based semiconducting PCPs with π stacking-dependent conductivity tunability is achieved. The π stacking distances and ligand conformation in these isoreticular PCPs were modulated by employing metal centers with different coordination geometries. As a result, three conjugated PCPs (Co−pyNDI, Ni−pyNDI, and Zn−pyNDI) with varying pore structure and conductivity were obtained. Their crystal structures were determined by three-dimensional electron diffraction. The through-space charge transfer and tunable pore structure in these PCPs result in modulated selectivity and sensitivity in gas sensing. Zn−pyNDI can serve as a room-temperature operable chemiresistive sensor selective to acetone.     

A simple and rapid route for synthesizing the nanosized g-C3N4 materials with narrow bandgap and their photocatalytic activity

The graphitic carbon nitride (g-C₃N₄) materials with many intriguing properties have attracted much attention in photocatalysis. The photocatalytic activity of g-C₃N₄ is hindered by serious aggregation and limited exposed active sites. Herein is shown that nanosized g-C₃N₄ can be simply obtained by a superfast high-pressure homogenization approach. The high-pressure homogenization treatment can provide strong force to cut and/or to exfoliate the bulk g-C₃N₄ into nanosized g-C₃N₄ with good dispersion. Moreover, choosing different solvents during treatment can cause a different surface structure of as-prepared nanosized g-C₃N₄. In addition, the narrow bandgap properties, the high photogenerated charge carrier separation, and the transport abilities are achieved in as-prepared nanosized g-C₃N₄ because of the retaining conjugated C₃N₄ system. Specifically, the photocatalytic activities of as-prepared nanosized g-C₃N₄ have been significantly enhanced in terms of degradation of organic dye Rhodamine B (RhB) under visible light irradiation (10 times higher than that of bulk g-C₃N₄). These findings can provide a promising and simple approach to the exfoliation, nanonization, and surface functionalization of 2D layered materials.     

Overreact,an in silico lab: Automative quantum chemical microkinetic simulations for complex chemical reactions

Today's demand for precisely predicting chemical reactions from first principles requires research to go beyond Gibbs' free energy diagrams and consider other effects such as concentrations and quantum tunneling. The present work introduces overreact, a novel Python package for propagating chemical reactions over time using data from computational chemistry only. The overreact code infers all differential equations and parameters from a simple input that consists of a set of chemical equations and quantum chemistry package outputs for each chemical species. We evaluate some applications from the literature: gas-phase eclipsed-staggered isomerization of ethane, gas-phase umbrella inversion of ammonia, gas-phase degradation of methane by chlorine radical, and three solvation-phase reactions. Furthermore, we comment on a simple solvation-phase acid–base equilibrium. We show how it is possible to achieve reaction profiles and information matching experiments.     

How deeply are core electrons perturbed when valence electrons are spin polarized? The case study of transition metal compounds

The ferromagnetic and antiferromagnetic wave functions of the KMnF₃ perovskite have been evaluated quantum-mechanically by using an all electron approach and, for comparison, pseudopotentials on the transition metal and the fluorine ions. It is shown that the different number of α and β electrons in the d shell of Mn perturbs the inner shells, with shifts between the α and β eigenvalues that can be as large as 6 eV for the 3s level, and is far from negligible also for the 2s and 2p states. The valence electrons of F are polarized by the majority spin electrons of Mn, and in turn, spin polarize their 1s electrons. When a pseudopotential is used, such a spin polarization of the core functions of Mn and F can obviously not take place. The importance of such a spin polarization can be appreciated by comparing (i) the spin density at the Mn and F nuclear position, and then the Fermi contact constant, a crucial quantity for the hyperfine coupling, and (ii) the ferromagnetic–antiferromagnetic energy difference, when obtained with an all electron or a pseudopotential scheme, and exploring how the latter varies with pressure. This difference is as large as 50% of the all electron datum, and is mainly due to the rigid treatment of the F ion core. The effect of five different functionals on the core spin polarization is documented.     

Enantiomeric analysis of drugs in water samples by using liquid–liquid microextraction and nano-liquid chromatography

The nano-LC technique is increasingly used for both fast studies on enantiomeric analysis and test beds of novel stationary phases due to the small volumes involved and the short conditioning and analysis times. In this study, the enantioseparation of 10 drugs from different families was carried out by nano-LC, utilizing silica with immobilized amylose tris(3-chloro-5-methylphenylcarbamate) column. The effect on chiral separation caused by the addition of different salts to the mobile phase was evaluated. To simultaneously separate as many enantiomers as possible, the effect of buffer concentration in the mobile phase was studied, and, to increase the sensitivity, a liquid–liquid microextraction based on the use of isoamyl acetate as sustainable extraction solvent was applied to pre-concentrate four chiral drugs from tap and environmental waters, achieving satisfactory recoveries (>70%).     

环境响应性微胶囊及其在农业领域中应用的研究进展

在传统农业中,如何高效率地使用农药,提高其利用率,一直是一大难题。环境响应性微胶囊是一类在外界环境的刺激下,可以相适应地改变其表面结构的物质。这一类微胶囊具有智能、可控、精准、高效等特点。目前,这一项技术已经被广泛地应用于农业生产中。本文主要综述了环境中pH、温度、光以及磁场四大因素对响应性微胶囊的影响,并且简要介绍了该类微胶囊的制备技术、形成机理、主要材料以及在农业领域的应用。     

Increasing Reduction Potentials of Type 1 Copper Center and Catalytic Efficiency of Small Laccase from Streptomyces coelicolor through Secondary Coordination Sphere Mutations

The key to type 1 copper (T1Cu) function lies in the fine tuning of the Cu^II/I reduction potential (E°′_T1Cu) to match those of its redox partners, enabling efficient electron transfer in a wide range of biological systems. While the secondary coordination sphere (SCS) effects have been used to tune E°′_T1Cu in azurin over a wide range, these principles are yet to be generalized to other T1Cu-containing proteins to tune catalytic properties. To this end, we have examined the effects of Y229F, V290N and S292F mutations around the T1Cu of small laccase (SLAC) from Streptomyces coelicolor to match the high E°′_T1Cu of fungal laccases. Using ultraviolet-visible absorption and electron paramagnetic resonance spectroscopies, together with X-ray crystallography and redox titrations, we have probed the influence of SCS mutations on the T1Cu and corresponding E°′_T1Cu. While minimal and small E°′_T1Cu increases are observed in Y229F- and S292F-SLAC, the V290N mutant exhibits a major E°′_T1Cu increase. Moreover, the influence of these mutations on E°′_T1Cu is additive, culminating in a triple mutant Y229F/V290N/S292F-SLAC with the highest E°′_T1Cu of 556 mV vs. SHE reported to date. Further activity assays indicate that all mutants retain oxygen reduction reaction activity, and display improved catalytic efficiencies (k_cat/K_M) relative to WT-SLAC.     

The Universal Super Cation-Conductivity in Multiple-cation Mixed Chloride Solid-State Electrolytes

As exciting candidates for next-generation energy storage, all-solid-state lithium batteries (ASSLBs) are highly dependent on advanced solid-state electrolytes (SSEs). Here, using cost-effective LaCl₃ and CeCl₃ lattice (UCl₃-type structure) as the host and further combined with a multiple-cation mixed strategy, we report a series of UCl₃-type SSEs with high room-temperature ionic conductivities over 10⁻³ S cm⁻¹ and good compatibility with high-voltage oxide cathodes. The intrinsic large-size hexagonal one-dimensional channels and highly disordered amorphous phase induced by multi-metal cation species are believed to trigger fast multiple ionic conductions of Li⁺, Na⁺, K⁺, Cu⁺, and Ag⁺. The UCl₃-type SSEs enable a stable prototype ASSLB capable of over 3000 cycles and high reversibility at −30 °C. Further exploration of the brand-new multiple-cation mixed chlorides is likely to lead to the development of advanced halide SSEs suitable for ASSLBs with high energy density.     

Palladium-Catalyzed Skeletal Rearrangement of Substituted 2-Silylaryl Triflates via 1,5-C−Pd/C−Si Bond Exchange

A palladium-catalyzed skeletal rearrangement of 2-(2-allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5-C−Pd/C−Si bond exchange. The reaction pathways can be switched toward 4-membered ring-forming C(sp²)−H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C−Pd/C−Si bond exchange.