In this work, we studied the reaction mechanisms for CO2 reduction reaction (CRR) on the iron-doped graphene and its coordinating sulfur (S) and nitrogen (N) variants, FeNnS4-n (n=1-4), using density functional theory calculations. Our results revealed that the electronic property and catalytic reactivity of the surfaces can be tuned by varying the N and S atoms ratio. The CRR activities of the mixed surfaces, FeN3S1, FeN2S2, and FeN1S3, were better than FeN4 and FeS4, where the absolute value of the limiting potential of the mixed surface decreased by 0.3 V. Considering the stability, we suggest FeN3S surface to be favorable for CRR. For the bare surfaces, we found a positive linear correlation between the magnetic moment and the charge of Fe metal. For these surfaces, the reduction of CO (*CO + (H++e−)→ *CHO) was important in deciding the limiting potential. We found that the adsorption energy of CO displayed a volcano relationship with the magnetic moment of the Fe atom. The study showed that the change of local coordinating structure around the Fe atom could modify the electronic and magnetic properties of the active Fe center and improve the CRR activity performance.
Towards Precision Ecotoxicology: Leveraging Evolutionary Conservation of Pharmaceutical and Personal Care Product Targets to Understand Adverse Outcomes Across Species and Life Stages
Abstract
Environmental science aims to protect biodiversity and ecosystem services, and our future ability to do that relies on a developing a precision ecotoxicology approach where we leverage the genetics and informatics of species to better understand and manage the risks of global pollution. A little over a decade ago, a workshop focusing on the risks of pharmaceuticals and personal care products (PPCPs) in the environment identified a priority research question, “What can be learned about the evolutionary conservation of PPCP targets across species and life stages in the context of potential adverse outcomes and effects?” Here we review the activities in this area over the past decade, consider prospects of more recent developments, and identify future research needs to develop next generation approaches for PPCPs and other global chemicals and waste challenges.
Microsecond dynamics of H10N7 influenza neuraminidase reveals the plasticity of loop regions and drug resistance due to the R292K mutation
The R292K mutation in N7 contributes to drug resistance by inducing structural destabilization, resulting in disrupted ligand-protein interactions, perturbed hydrogen bonds, and an increased SASA around K292.
Abstract
At the beginning of the last century, multiple pandemics caused by influenza (flu) viruses severely impacted public health. Despite the development of vaccinations and antiviral medications to prevent and control impending flu outbreaks, unforeseen novel strains and continuously evolving old strains continue to represent a serious threat to human life. Therefore, the recently identified H10N7, for which not much data is available for rational structure-based drug design, needs to be further explored. Here, we investigated the structural dynamics of neuraminidase N7 upon binding of inhibitors, and the drug resistance mechanisms against the oseltamivir (OTV) and laninamivir (LNV) antivirals due to the crucial R292K mutation on the N7 using the computational microscope, molecular dynamics (MD) simulations. In this study, each system underwent long 2 × 1 μs MD simulations to answer the conformational changes and drug resistance mechanisms. These long time-scale dynamics simulations and free energy landscapes demonstrated that the mutant systems showed a high degree of conformational variation compared to their wildtype (WT) counterparts, and the LNV-bound mutant exhibited an extended 150-loop conformation. Further, the molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) calculation and MM/GBSA free energy decomposition were used to characterize the binding of OTV and LNV with WT, and R292K mutated N7, revealing the R292K mutation as drug-resistant, facilitated by a decline in binding interaction and a reduction in the dehydration penalty. Due to the broader binding pocket cavity of the smaller K292 mutant residue relative to the wildtype, the drug carboxylate to K292 hydrogen bonding was lost, and the area surrounding the K292 residue was more accessible to water molecules. This implies that drug resistance could be reduced by strengthening the hydrogen bond contacts between N7 inhibitors and altered N7, creating inhibitors that can form a hydrogen bond to the mutant K292, or preserving the closed cavity conformations.
Coherent manipulation of intensity interrogation of sensitivity of the surface plasmon polariton waves at the dielectric and silver metal interface
The light passes through the prism at a fixed angle, then couple evanescently though dielectric medium and interact with the silver metal. Surface plasmons are excited at interface of metal and dielectric and decay exponentially along the distance from the interface. Part of the reflected light is absorbed due to coupling of incident light beam with SPPs. The dielectric medium is used to control the sensitivity of SPPs to our chance of demand.
Abstract
In this manuscript, Intensity interrogation of sensitivity of the surface plasmon polariton waves (SPPs) is coherently manipulated, at the interface of four-level dielectric medium and silver metal using prism geometry. Sensitivity of SPPs with respect to refractive index is written as dI/dnd$$ dI/d{n}_d $$. A useful control in sensitivity is reported with probe and control fields detuning, Rabi frequency and decay rate. Sensitivity is a function of probe field detuning and control field Rabi frequency. The maximum sensitivity is reported to 400 Wm−2/RIU$$ 400\;{\mathrm{Wm}}^{-2}/\mathrm{RIU} $$ with probe field detuning and control field Rabi frequency, while minimum sensitivity is investigated to 34 Wm−2/RIU$$ 34\;{\mathrm{Wm}}^{-2}/\mathrm{RIU} $$ with control field phase and control field Rabi frequency. The sensitivity in this manuscript shows useful application in biosensor and photovoltaic devices.
Synthesis of nickel oxide nanoparticles from Enicostemma littorale plant extract and investigation of their photocatalytic and antimicrobial properties
Nickel oxide nanoparticle (NiOxi-NP) synthesized from Enicostemma littorale (ESL) plant extract has a spherical shape (33–46 nm) with face centre cubic lattice showing two intense peaks at 2θ = 36.42° (111) and 42.87° (200). It shows better anticancer activity on the (MCF-7) breast tumour cancer cell line (MCF-7) with the IC50 value of 12.87 μg/mL. It shows better antibacterial activity on harmful bacteria and photodegradation of the dye rhodamine B (RBD) in 16 min at 0.025 mg/L
Nickel oxide nanoparticles (NiOxi-NPs) with a spherical shape have been developed using a green aqueous extract of the Enicostemma littorale plant, and their efficacy on various photochemical and biological applications like antibacterial and anticancer has been studied. The intense vibrational bands in the Fourier transformer infrared spectroscopy (FT-IR) spectrum correspond to Ni-O, C=O, and O-H, confirming the formation of NiOxi-NP. Also, two intense peaks at 2θ = 36.42° (111) and 42.87° (200) in the X-ray diffraction (XRD) spectrum confirm the NiOxi-NP crystal lattice as face center cubic (FCC). To determine the light-absorbing behavior and shape of the newly produced NiOxi-NP, UV-visible, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) investigations were performed. NiOxi-NP has a maximal distinctive UV-visible absorption wavelength in the 306-nm region. The nickel oxide nanoparticles are formed in spherical form and dispersed in the 33- to 46-nm size range, according to the SEM and TEM investigations. According to the 3-(4,5-dimethyl thiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, the Michigan Cancer Foundation-7 (MCF-7) breast tumor cancer cell line is extremely responsive to the green NiOxi-NPs' exceptional lethal effectiveness. The IC50 value for MCF-7 cell lines is 12.87 μg/mL. When tested against bacteria such as Bacillus subtilis, Staphylococcus, and Escherichia coli stains, the aforementioned particles demonstrate greater activity on the three bacteria. The photocatalytic activity of the greenery NiOxi-NP over the dye rhodamine B (RBD) was finished in 16 min when the solution concentration was 0.025 mg/L. The green synthesis of NiOxi-NP nanoparticles can behave as a better UV-visible screener between 290 and 450 nm, a better antimicrobial agent, a better RBD degradation agent, and a better low-dose anticancer agent.
Bio‐Inspired Far‐From‐Equilibrium Hydrogels: Design Principles and Applications
Inspired from dynamic living systems that operate under out-of-equilibrium conditions in biology, developing supramolecular hydrogels with self-regulating and autonomously dynamic properties to further advance adaptive hydrogels with life-like behavior is important. This review presents recent progress of bio-inspired supramolecular hydrogels out-of-equilibrium. The principle of out-of-equilibrium self-assembly for creating bio-inspired hydrogels is discussed. Various design strategies have been identified, such as chemical-driven reaction cycles with feedback control and physically oscillatory systems. These strategies can be coupled with hydrogels to achieve temporal and spatial control over structural and mechanical properties as well as programmable lifetime. These studies open up huge opportunities for potential applications, such as fluidic guidance, information storage, drug delivery, actuators and more. Finally, we address the challenges ahead of us in the coming years, and future possibilities and prospects are identified.
Nickel‐Catalyzed Stereoselective Migratory Carboboration of 1,4‐Cyclohexadiene
Comprehensive Summary
Multi-substituted cyclohexanes play a crucial role as scaffolds in bioactive compounds. While significant progress has been made in synthesising substituted cyclohexanes, methods for the stereoselective assembly of 1,3-disubstituted cyclohexanes remain scarce. This study presents a novel approach involving nickel catalysis to achieve stereoselective carboboration of 1,4-cyclohexadiene. This innovative process allows for the simultaneous introduction of a boron group and an aryl or an alkyl fragment into the 1,4-cyclohexadiene framework under mild conditions, with exclusive regioselectivity and excellent cis configuration. The resulting products feature a double carbon bond and the incorporation of the boron group, offering significant potential for subsequent transformations and downstream applications.
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[ASAP] Cavity Control of Molecular Spectroscopy and Photophysics
Accounts of Chemical Research
DOI: 10.1021/acs.accounts.3c00280
[ASAP] Mapping the Direction of Nucleocytoplasmic Transport of Glucocorticoid Receptor (GR) in Live Cells Using Two-Foci Cross-Correlation in Massively Parallel Fluorescence Correlation Spectroscopy (mpFCS)
Analytical Chemistry
DOI: 10.1021/acs.analchem.3c01427
One‐Pot Conversion of Benzyl Alcohols to N‐Protected Anilines and Alkyl Alcohols to Carbamoyl Azides
One-pot, scalable procedures converting benzylic or aliphatic alcohols to various N-functionalized amines are reported in 38-83% overall yields. These multi-step conversions are relatively economic and involve the oxidative formation of acid chloride intermediates and the Curtius rearrangement of acyl azides. Notable aspects of economy include: (1) the use of a relatively green solvent (chlorobenzene) that tolerates both ionic and radical reactions, without the need for rigorously dry or O2-free conditions; (2) the use of minimal amounts of trichloroisocyanuric acid (TCCA) as a cheap and green chlorinating agent to oxidize the alcohol starting materials and then transform the aldehyde intermediates to acid chlorides under photoirradiation for azide addition; (3) the efficient capture of isocyanate intermediates by alcohol or azide nucleophiles providing N-protected anilines or N-protected alkylamines, respectively, the latter of which was employed in the synthesis of an anti-dementia drug, memantine hydrochloride, over two purification steps.