Chemical Selectivity Research Articles

Recent advancement in nanomaterials for the detection and removal of uranium: A review

Uranyl ions U(VI), are the common by-product of nuclear power plants and anthropogenic activities like mining, excess utilization of fertilizers, oil industries, etc. Its intake into the body causes serious health concerns such as liver toxicity, brain damage, DNA damage and reproductive issues. Therefore, there is urgent need to develop the detection and remediation strategies. Nanomaterials (NMs), due to their unique physiochemical properties including very high specific area, tiny sizes, quantum effects, high chemical reactivity and selectivity have become emerging materials for the detection and remediation of these radioactive wastes. Therefore, the current study aims to provide a holistic view and investigation of these new emerging NMs that are effective for the detection and removal of Uranium including metal nanoparticles, carbon-based NMs, nanosized metal oxides, metal sulfides, metal-organic frameworks, cellulose NMs, metal carbides/nitrides, and carbon dots (CDs). Along with this, the production status, and its contamination data in food, water, and soil samples all across the world are also complied in this work.

A key to totipotency: Wuschel-like homeobox 2a unlocks embryogenic culture response in maize (Zea mays L.).

The ability of plant somatic cells to dedifferentiate, form somatic embryos and regenerate whole plants in vitro has been harnessed for both clonal propagation and as a key component of plant genetic engineering systems. Embryogenic culture response is significantly limited, however, by plant genotype in most species. This impedes advancements in both plant transformation-based functional genomics research and crop improvement efforts. We utilized natural variation among maize inbred lines to genetically map somatic embryo generation potential in tissue culture and identify candidate genes underlying totipotency. Using a series of maize lines derived from crosses involving the culturable parent A188 and the non-responsive parent B73, we identified a region on chromosome 3 associated with embryogenic culture response and focused on three candidate genes within the region based on genetic position and expression pattern. Two candidate genes showed no effect when ectopically expressed in B73, but the gene Wox2a was found to induce somatic embryogenesis and embryogenic callus proliferation. Transgenic B73 cells with strong constitutive expression of the B73 and A188 coding sequences of Wox2a were found to produce somatic embryos at similar frequencies, demonstrating that sufficient expression of either allele could rescue the embryogenic culture phenotype. Transgenic B73 plants were regenerated from the somatic embryos without chemical selection and no pleiotropic effects were observed in the Wox2a overexpression lines in the regenerated T0 plants or in the two independent events which produced T1 progeny. In addition to linking natural variation in tissue culture response to Wox2a, our data support the utility of Wox2a in enabling transformation of recalcitrant genotypes.

A Review: Combination of Fungicide, Polymer Coating and Packaging Materials on Improve Germination Rate and Improve Uniformity of Seedling Emergence of Different Seeds during Storage

Seed coating is a method of encasing seeds in adhesive materials to improve germination and performance while lowering cost. Seed coating has been widely used in agriculture as an efficient way to reduce biotic and abiotic stressors, hence boosting crop growth, productivity, and health, in order to satisfy the demands of the development of precision agriculture. Plant-beneficial microorganisms include Trichoderma, rhizobium, arbuscular mycorrhizal fungusfungi and plant growth-promoting bacteria. Fungicide seed treatment is easy, affordable, and efficient. Additionally, it is well known that the selection of chemicals for seed treatment also has a favourable impact on seed viability and vigour during germination storage. Seed coating polymers are utilised in conjunction with active components like fungicides and insecticides. A new era of biocontrol techniques has recently begun. By utilising hostile microbes to fight seed-borne illnesses, new technology is being developed. Beneficial fungus like Trichoderma harzianum and Trichoderma viride are among the bioagents most powerful and efficient fungus- and soil-borne pathogen suppressants such as seedling blight, collar rot, stem rot, root rot, dry root rot, and their use may can effectively manage each of these illnesses, and thus encourage crop growth and yield.

Diversifying the functions of heme proteins with non-porphyrin cofactors

Heme proteins perform diverse biochemical functions using a single iron porphyrin cofactor. This versatility makes them attractive platforms for the development of new functional proteins. While directed evolution and metal substitution have expanded the properties, reactivity, and applications of heme proteins, the incorporation of porphyrin analogs remains an underexplored approach. This review discusses the replacement of heme with non-porphyrin cofactors, such as porphycene, corrole, tetradehydrocorrin, phthalocyanine, and salophen, and the attendant properties of these conjugates. While structurally similar, each ligand exhibits distinct optical and redox properties, as well as unique chemical reactivity. These hybrids serve as model systems to elucidate the effects of the protein environment on the electronic structure, redox potentials, optical properties, or other features of the porphyrin analog. Protein encapsulation can confer distinct chemical reactivity or selectivity of artificial metalloenzymes that cannot be achieved with the small molecule catalyst alone. Additionally, these conjugates can interfere with heme acquisition and uptake in pathogenic bacteria, providing an inroad to innovative antibiotic strategies. Together, these examples illustrate the diverse functionality that can be achieved by cofactor substitution. The further expansion of this approach will access unexplored chemical space, enabling the development of superior catalysts and the creation of heme proteins with emergent properties.

Metasurface-Enhanced Mid-Infrared Spectrochemical Imaging of Tissues.

Label-free and nondestructive mid-infrared vibrational hyperspectral imaging is an essential tissue analysis tool, providing spatially resolved biochemical information critical to understanding physiological and pathological processes. However, the chemically complex and spatially heterogeneous composition of tissue specimens and the inherently weak interaction of infrared light with biomolecules limit the analytical performance of infrared absorption spectroscopy. Here, an advanced mid-infrared spectrochemical tissue imaging modality is introduced using metasurfaces that support strong surface-localized electromagnetic fields to capture quantitative molecular maps of large-area murine brain tissue sections. The approach leverages polarization-multiplexed multi-resonance plasmonic metasurfaces to simultaneously detect various functional biomolecules. The surface-enhanced mid-infrared spectral imaging method eliminates the non-specific effects of bulk tissue morphology on quantitative spectral analysis and improves chemical selectivity. This study shows that metasurface enhancement increases the retrieval of amide I and II bands associated with protein secondary structures. Moreover, it is demonstrated that plasmonic metasurfaces enhance the chemical contrast in infrared images and enable detection of ultrathin tissue regions that are not otherwise visible to conventional mid-infrared spectral imaging. While this work uses murine brain tissue sections, thechemical imaging method is well-suited for other tissue types, which broadens its potential impact for translational research and clinical histopathology.

Plasmonics: A Versatile Toolbox for Heterogeneous Photocatalysis

Plasmonic photocatalysis is a dynamic field of research devoted to the activation of chemical transformations thanks to the unique optoelectronic features of plasmonic nanomaterials such as their high electromagnetic field enhancements or their ability to generate nonthermalized charge carriers and localized temperature gradients. Importantly, the use of these objects as photocatalysts can lead to new reactivities when compared with classical heterogeneous photocatalysts, including an unprecedented control over efficiency and chemical selectivity within a broader range of the solar spectrum. In the present study, the most important aspects that need to be taken into consideration when designing a plasmonic photocatalytic system are summarized. Representative examples from the literature toward the rational design of the plasmonic photocatalyst are provided, together with a comprehensive list of organic and inorganic transformations that have been successfully modulated by plasmons. The importance of single nanoparticle measurements as a new means to characterize these systems is also discussed, allowing a better insight into single object heterogeneities or structure–function relationships that are usually lost in ensemble characterization techniques. Finally, the major role played by reaction intermediates when performing photoredox processes in solution is highlighted, particularly important when driving photochemical reactions in biological environments.

Experimental (FT‐Raman, FT‐IR and NMR) and theoretical (DFT) calculations, thermodynamic parameters, molecular docking and NLO (non-linear optical) properties of N‐(2,6‐dimethylphenyl)‐1‐piperazineacetamide

Abstract Theoretical and experimental studies are performed on the new organic–inorganic hybrid molecule N‐(2,6‐dimethylphenyl)‐1‐piperazineacetamide. The vibrational spectra of the molecule are characterized using FT‐IR and FT‐Raman in the range 4000–600 cm−1 and 4000–100 cm−1, respectively. Density functional theory with B3LYP/3‐21G and B3LYP/cc‐pVDZ basis sets is used to calculate energy, geometrical structure, and vibrational modes of stretching, bending, and torsion. The VEDA software Autodock Vina revealed a good binding is employed to calculate the detailed vibrational assignments. The theoretical and experimental vibrational data are compared to support the present study. Density functional theory is used to calculate thermodynamic parameters (heat capacity, entropy, and enthalpy) and nonlinear optical properties. The software Gaussian09W and Gaussview 6.0 are used for theoretical calculations. Molecular docking studies are carried out to investigate the effect of the titled molecule against various proteins such as SARS‐CoV‐2 that affect the immune system in humans. Chemical shifts are identified using carbon and proton NMR. Non‐covalent interactions are studied using a reduced density gradient. The chemical reactivity and selectivity for a local reactivity site are analyzed with the help of Fukui functions.

Amidoxime-Based Polymer Microspheres with High Selectivity for Uranium from Saline Lake Brine

Uranium is the most basic ingredient for nuclear energy production, and its sources are mainly concentrated in mineral, as well as seawater and saline lake brine. Amidoxime-based functional adsorbents play an indispensable role in the efficient recovery of uranium from varied sources. However, it is empirically considered that for amidoxime adsorbents, balancing adsorption capacity and selectivity is challenging in the presence of complex interfering ions, especially for vanadium. Herein, a kind of amidoxime-modified mesoporous polymer microsphere with an optimized distance among functional groups was synthesized, which has remarkable chemical stability and ion selectivity. It is impressive that the adsorption capacity of the above-mentioned amidoxime microspheres for uranium in natural saline lake brine reached 15.9 mg/g, which was two orders of magnitude higher than that of vanadium. Combined with enhanced adsorption capacity, excellent selectivity, and ultra-high stability, amidoxime-functionalized mesoporous polymer microspheres emerge as a promising adsorbent for uranium extraction from natural saline lake brine.

Electric‐Field‐Induced Organic Transformations

AbstractExperiments showed that the existence of electric fields in non‐redox processes may alter the catalytic activity, rate enhancement, and selection of organic reactions. It is expected that the interaction between electric fields and chemical reactions will create new avenues for producing materials with desired properties in several chemical disciplines, including synthetic organic chemistry, catalysis, nanotechnology, membrane technology, and enzyme catalysis. Specifically, in this review, we discuss the elegant experimental investigations carried out using the scanning tunneling microscope, the interfacial electric field, and designed local electric fields. The results of these studies are remarkable, leading to new information on the function of electric fields in controlling chemical reactivity and selectivity in different reactions and offering a glimpse of the great potential of electrostatic fields. This article not only presents the core concepts of field‐induced chemical transformations but also illustrates the potential use of electric field catalysis in chemistry and other fields.

Adaptive Encapsulation of 1,ω‐Amino‐Acids within the “Pyrene Box”

AbstractPyrene boxes, self‐assembled from 1,3,5,8‐pyrene‐tetrasulfonate anions, PTS4− and Guanidinium G+, amino‐guanidinium AG+ and hydrated alkali counter cations have been used for the encapsulation of 1,ω‐amino‐acids of variable lengths. The NMR spectroscopy illustrates that these systems are stable in aqueous solution and encapsulation process involves dynamic or fixed guest molecules within Pyrene box, depending of the nature of the counter‐cations. The amide bond coupling between the amino‐guanidinium AG+ and encapsulated 1,ω‐amino‐acid guests occur in water in the absence of coupling catalysts. The variable co‐encapsulation of the guests via multivalent stabilizing interactions shed light that chemical selection can be obtained from mixtures of 1,ω‐amino‐acids. Our study involving a comprehensive screening of 18 co‐crystal structures help to understand the in‐situ fixation of 1,ω‐amino‐acid guests and their accurate determination of unconventional structures under confinement.

In situ biomonitoring using caged lumpfish (Cyclopterus lumpus) eggs reveal plastic and rubber associated chemicals in a harbour area in Central Norway

ABSTRACT Plastics- and rubber-derived chemicals are given increasing focus due to their migration into the environment and potential for causing detrimental effects. The current study demonstrates the use of a novel biomonitoring platform using caged fertilized eggs of lumpfish (Cyclopterus lumpus) in combination with gas chromatography tandem mass spectrometry analysis of a selection of target chemicals extracted from the lumpfish eggs after deployment. A monitoring campaign in the Trondheim harbor and off the coast of Trøndelag in Norway was executed using the described system. Here we found accumulation of UV stabilizers (benzophenone and benzothiazoles), plasticizers (n-butylbenzenesulfonamide), reagents, and polymer synthesis precursors (bisphenol A, acetophenone, phthalide, and phthalimide) in deployed eggs. Several of the compounds were detected in concentrations above previously quantified legacy contaminants in the same study areas.

Highly selective PtCo bimetallic nanoparticles on silica for continuous production of hydrogen from aqueous phase reforming of xylose

Hydrogen (H2) is a promising energy vector for mitigating greenhouse gas emissions. Lignocellulosic biomass waste has been introduced as one of the abundant and carbon-neutral H2 sources. Among those, xylose with its short carbon chain has emerged attractive, where H2 can be catalytically released in an aqueous reactor. In this study, a composite catalyst system consisting of silica (SiO2)-supported platinum (Pt)-cobalt (Co) bimetallic nanoparticles was developed for aqueous phase reforming of xylose conducted at 225 °C and 29.3 bar. The PtCo/SiO2 catalyst showed a significantly higher H2 production rate and selectivity than that of Pt/SiO2, whereas Co/SiO2 shows no activity in H2 production. The highest selectivity for useful liquid byproducts was obtained with PtCo/SiO2. Moreover, CO2 emissions throughout the reaction were reduced compared to those of monometallic Pt/SiO2. The PtCo bimetallic nanocatalyst offers an inexpensive, sustainable, and durable solution with high chemical selectivity for scalable reforming of hard-to-ferment pentose sugars.

Development of a reference and proficiency chemical list for human steatosis endpoints in vitro.

The most prevalent liver disease in humans is non-alcoholic fatty liver disease, characterised by excessive hepatic fat accumulation, or steatosis. The western diet and a sedentary lifestyle are considered to be major influences, but chemical exposure may also play a role. Suspected environmental chemicals of concern include pesticides, plasticizers, metals, and perfluorinated compounds. Here we present a detailed literature analysis of chemicals that may (or may not) be implicated in lipid accumulation in the liver, to provide a basis for developing and optimizing human steatosis-relevant in vitro test methods. Independently collated and reviewed reference and proficiency chemicals are needed to assist in the test method development where an assay is intended to ultimately be taken forward for OECD Test Guideline development purposes. The selection criteria and considerations required for acceptance of proficiency chemical selection for OECD Test Guideline development. (i.e., structural diversity, range of activity including negatives, relevant chemical sectors, global restrictions, etc.) is described herein. Of 160 chemicals initially screened for inclusion, 36 were prioritized for detailed review. Based on the selection criteria and a weight-of-evidence basis, 18 chemicals (9 steatosis inducers, 9 negatives), including some environmental chemicals of concern, were ranked as high priority chemicals to assist in vitro human steatosis test method optimisation and proficiency testing, and inform potential subsequent test method (pre-)validation.

Robust Electrostatically Interactive Hydrogel Coatings for Macroscopic Supramolecular Assembly via Rapid Wet Adhesion

A macroscopic supramolecular assembly (MSA) refers to non-covalent interactions between building blocks over a micrometer scale, which provides insights into bio-/wet adhesion, self-healing, and so on and new fabrication strategies to heterogeneous structures and bio-scaffolds. The key to realize the MSA of rigid materials is pre-modifying a compliant coating known as a "flexible spacing coating" beneath the interactive moieties. However, available coatings are limited to polyelectrolyte multilayers with shortcomings of tedious fabrication, weak adhesion to substrates, susceptibility to external reagents, and so on. Here, we develop a facile method to induce a new "flexible spacing coating" of a poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel with electrostatic interactions to achieve MSA of diverse rigid materials (quartz, metal, rubber, and plastics). Selective self-assembly of positive-negative charged surfaces is observed by the naked eye under 3 min of shaking in water, providing strategies to rapid wet adhesion. The interfacial binding force between positive-negative interacted surfaces is 1018.1 ± 299.2 N/m2, which is over two magnitudes larger than that of control groups, that is, positive-positive (24.4 ± 10.0 N/m2) and negative-negative (67.5 ± 16.7 N/m2) interacted surfaces. In situ force measurements and control experiments of identically charged building blocks have strongly supported the improved binding strength and chemical selectivity between interactive building blocks. The coating is advantageous with a simple fabrication, strong adhesion to materials, robust solvent tolerance to assembly solutions, and feasibility of photo-patterning. We envision that the above strategy would broaden the material choices of flexible spacing coatings for efficient MSA and new methods for rapid interfacial adhesion.

Illuminating the Chemical Space of Untargeted Proteins

According to the Illuminating the Druggable Genome (IDG) initiative, 90% of the proteins encoded by the human genome still lack an identified active ligand, that is, a small molecule with biologically relevant binding potency or functional activity in an in vitro assay. Under this scenario, there is an urgent need for new approaches to chemically address these yet untargeted proteins. It is widely recognized that the best starting point for generating novel small molecules for proteins is to exploit the expected polypharmacology of known active ligands across phylogenetically related proteins following the paradigm that similar proteins are likely to interact with similar ligands. Here, we introduce a computational strategy to identify privileged structures that, when chemically expanded, are highly probable to contain active small molecules for untargeted proteins. The protocol was first tested on a set of 576 currently targeted proteins having at least one protein family sibling the year before their first active ligand was reported. A privileged structure contained in active ligands that were identified in the following years was correctly anticipated for 214 (37%) of those targeted proteins, a lower-bound recall estimate when considering data completeness issues. When applied to a set of 1184 untargeted potential druggable genes in cancer, the identification of privileged structures from known bioactive ligands of protein family siblings allowed for extracting a priority list of diverse commercially available small molecules for 960 of them. Assuming a minimum success rate of 37%, the chemical library selections should be able to deliver active ligands for at least 355 currently untargeted proteins associated with cancer.

Consequence analysis in industrial organizations containing H2S gas through accident scenarios based on chemical source selection

AbstractH2S gas emissions occur in various processes, especially in the purification of polluted waters, mining, and petroleum refining processes and this extremely dangerous chemical has serious toxic emission, explosion, and fire effects. These physical effects vary considerably depending on the source strength. Therefore, consequence analyzes based on source strength models are critical components in the process of assessing hazards. In this study, a consequence analysis was performed with accident scenarios related to different sources of H2S gas. ALOHA 5.4.7 and EFFECTS 8.0.1 Software were used for physical effects modeling. Modeling studies were conducted on direct source (continuous release:100 m3/s, 5 m3/s), puddle source (100 m3, 5 m3), tank source (vertical‐horizontal cylindrical, spherical, 1.57 m3), and gas pipeline source with ALOHA Software. Possible Gas LOC (Levels of Concern) scenario Leak (G3) and Gas LOC scenario release in 10 min (G2) scenarios were studied with EFFECTS Software. When the results of both software were compared with each other, it was seen that the effects of thermal radiation and explosion were of similar order and value, and the toxic effect values were very different from each other. Both software allow for a release above ground level for gases that behave as neutrally buoyant. The main difference between the dispersion models used in the software is that the gas is assumed to behave as non‐interacting ideal gas in ALOHA, but in EFFECTS deviations from ideal gas are considered. And, ALOHA dispersion models use surface roughness lengths in a limited fashion and only include 60‐min AEGLs. ALOHA does not account for topographic steering or winds that vary with time in EFFECTS. It can be said that the results of the ALOHA Software are more conservative than the EFFECTS Software.

Improving molecular representation learning with metric learning-enhanced optimal transport

Training data are usually limited or heterogeneous in many chemical and biological applications. Existing machine learning models for chemistry and materials science fail to consider generalizing beyond training domains. In this article, we develop a novel optimal transport-based algorithm termed MROT to enhance their generalization capability for molecular regression problems. MROT learns a continuous label of the data by measuring a new metric of domain distances and a posterior variance regularization over the transport plan to bridge the chemical domain gap. Among downstream tasks, we consider basic chemical regression tasks in unsupervised and semi-supervised settings, including chemical property prediction and materials adsorption selection. Extensive experiments show that MROT significantly outperforms state-of-the-art models, showing promising potential in accelerating the discovery of new substances with desired properties.

Electrocatalysis Cα–Cβ and Cβ–O bond cleavage of lignin model compound using Ni-Co/C as catalyst electrode in deep eutectic solventx

In this study, Cα–Cβ and Cβ–O bond cleavage of β-O-4 model compound (2-phenoxy-1-phenylethanol) were accomplished by electrocatalysis depolymerization process in deep eutectic solvents (DES) systems. We have investigated the application of Ni-Co/C catalysts on working electrode, which were synthesized with impregnation method. The Ni-Co/C with porous structure and abundant active sites, was shown an excellent electrocatalysis activity. Specific structure of Ni-Co/C could provide greatly efficient adsorption and desorption capacity to promote Cα–Cβ and Cβ–O bond cleavage. Therefore, in this electrocatalysis depolymerization process, the highest depolymerization rate exceeded 90%. And the yields (and conversion rates) of products (including benzaldehyde, acetophenone, benzoic acid, phenol) can reach to 124.08 mg/g (25.05%), 23.29 mg/g (4.15%), 44.64 mg/g (7.83%), 30.3 mg/g (6.9%). Furthermore, the electrocatalysis mechanism of Cα–Cβ and Cβ–O bond was investigated. The cleavage of Cα–Cβ and Cβ–O bond was initiated by in situ generated free radicals through Ni-Co/C. Then, the cleavage of Cα–Cβ and Cβ–O bond were occurred by ·OH and ·O2−. The results were showed that the Cα–Cβ bond cleavage was more in line with the β-C elimination and free radical pathways, and Cβ–O bond cleavage was consistent with direct oxidative addition. The enhanced electrocatalytic efficiency of the low-cost Ni-Co/C electrocatalyst combined with its good chemical stability and selectivity, which offer a promising route for developing an efficient lignin depolymerization technology.

Electrochemical Reduction of Quaternary Phosphonium Derivatives: A Systematic Optimization Approach

Triphenylphosphine (TPP) is one of the crucial reagents in Wittig olefination reactions. As part of the reaction, TPP will be sacrificed to yield the desired olefin (E/Z) as well as triphenylphosphine oxide (TPPO) containing a strong oxygen–phosphorus double bond (P═O). TPPO is considered thermodynamically stable but economically undesired. Conventional chemical recycling methods to reduce PV to PΙΙΙ utilize sacrificial reduction agents (silanes, boranes, and allanes). In recent years, many studies have focused on less toxic and sacrificial-agent-free alternative pathways. This study focuses on the optimization of an indirect electrochemical reduction of TPPO toward TPP, which becomes possible after the activation of TPPO with methyl triflate. Under optimized conditions, the P═O bond of TPPO is weakened to allow a current efficiency of up to 50% and a chemical selectivity of 99%.

Progress towards Stable and High-Performance Polyelectrolyte Multilayer Nanofiltration Membranes for Future Wastewater Treatment Applications

The increasing demand for nanofiltration processes in drinking water treatment, industrial separation and wastewater treatment processes has highlighted several shortcomings of current state-of-the-art thin film composite (TFC NF) membranes, including limitations in chemical resistance, fouling resistance and selectivity. Polyelectrolyte multilayer (PEM) membranes provide a viable, industrially applicable alternative, providing significant improvements in these limitations. Laboratory experiments using artificial feedwaters have demonstrated selectivity an order of magnitude higher than polyamide NF, significantly higher fouling resistance and excellent chemical resistance (e.g., 200,000 ppmh chlorine resistance and stability over the 0-14 pH range). This review provides a brief overview of the various parameters that can be modified during the layer-by-layer procedure to determine and fine-tune the properties of the resulting NF membrane. The different parameters that can be adjusted during the layer-by-layer process are presented, which are used to optimize the properties of the resulting nanofiltration membrane. Substantial progress in PEM membrane development is presented, particularly selectivity improvements, of which the most promising route seems to be asymmetric PEM NF membranes, offering a breakthrough in active layer thickness and organic/salt selectivity: an average of 98% micropollutant rejection coupled with a NaCl rejection below 15%. Advantages for wastewater treatment are highlighted, including high selectivity, fouling resistance, chemical stability and a wide range of cleaning methods. Additionally, disadvantages of the current PEM NF membranes are also outlined; while these may impede their use in some industrial wastewater applications, they are largely not restrictive. The effect of realistic feeds (wastewaters and challenging surface waters) on PEM NF membrane performance is also presented: pilot studies conducted for up to 12 months show stable rejection values and no significant irreversible fouling. We close our review by identifying research areas where further studies are needed to facilitate the adoption of this notable technology.