Dynamic systems, defined by their continuous temporal evolution, are central to advancements in chemistry, biology, and materials science. Optical techniques that leverage light absorption, scattering, and emission are essential for characterizing structural and property changes in these systems. However, conventional optical toolssuch as UV-vis spectroscopy, fluorescence, and scattering techniquesprovide fragmented or incomplete insights, making it challenging to comprehensively understand dynamic processes and ensure reliable data interpretation. Herein, we introduce a charge-coupled device (CCD)-based multitrack linearly polarized spectrometer (MLPS) designed for simultaneous kinetic UV-vis, polarization-resolved scattering, and photoluminescence measurements. The MLPS facilitates concurrent quantification of scattering and fluorescence intensities and depolarizations, alongside UV-vis extinction, with subsecond temporal resolution. By integrating high temporal resolution with the ability to capture complementary spectra, the MLPS significantly enhances the functionality of optical spectroscopy, paving the way for broader applications in dynamic system analysis and advancing research across multiple scientific disciplines. Furthermore, the instrument characterization and data preprocessing methodologies presented here provide valuable insights for the future development of multitrack CCD-based spectrometers.

UV-visible (UV-vis) spectrophotometry is a fundamental analytical technique widely used in chemistry, biology, materials science, and medical research. Despite its significance, undergraduate education often presents UV-vis spectroscopy narrowly as an absorbance-based method governed by the Beer-Lambert Law. This traditional framework, while effective for idealized solutions, fails to address the complexities of real-world samples that scatter or emit light, leading to widespread challenges in data interpretation. To bridge this gap, this work introduces an expanded pedagogical approach that incorporates the theoretical foundations of UV-vis spectroscopy for solutions exhibiting diverse optical behaviors. These include pure absorbers, pure scatterers, simultaneous absorbers and scatterers, simultaneous absorbers and emitters, and solutions that encompass absorption, scattering, and emission. We present accessible theoretical models designed to accommodate students with varying levels of mathematical proficiency, parametrizing UV-vis signals within the capabilities of standard spectrophotometers. Additionally, we outline instructional strategies to enhance comprehension across different educational levels, making these advanced concepts more approachable. This framework lays the groundwork for future studies that will feature laboratory modules leveraging commercially available UV-vis and fluorescence spectrophotometers to reinforce hands-on, evidence-based learning. By broadening the scope of UV-vis education and addressing critical gaps in traditional instruction, this work aims to deepen students' conceptual and practical understanding of spectroscopic analysis. Furthermore, it seeks to rectify common misinterpretations in the literature, equipping students with the analytical skills necessary for accurate, rigorous spectral interpretation. Ultimately, this effort aspires to transform UV-vis spectroscopy education by fostering both theoretical and practical mastery, preparing students for the challenges of modern scientific research and industry applications.

The COVID-19 pandemic has underscored the need for effective and affordable antiviral drugs. Anthropogenic activities have increased interactions among humans, animals, and wildlife, contributing to the emergence of new and re-emerging viral diseases. RNA viruses pose significant challenges due to their rapid mutation rates, high transmissibility, and ability to adapt to host immune responses and antiviral treatments. The World Health Organization has identified several diseases (COVID-19, Ebola, Marburg, Zika, and others), all caused by RNA viruses, designated as being of priority concern as potential causes of future pandemics. Despite advances in antiviral treatments, many viruses lack specific therapeutic options, and more importantly, there is a paucity of broad-spectrum antiviral drugs. Additionally, the high costs of current treatments such as Remdesivir and Paxlovid highlight the need for more affordable antiviral drugs. Cyclic peptides from natural sources or designed through molecular modeling have shown promise as antiviral drugs with stability, low toxicity, high target specificity, and low antiviral resistance properties. This review emphasizes the urgent need to develop specific and broad-spectrum antiviral drugs and highlights cyclic peptides as a sustainable solution to combat future pandemics. Further research into these compounds could provide a new weapon to combat RNA viruses and address the gaps in current antiviral drug development.

Malondialdehyde (MDA), a mutagenic and carcinogenic compound, is widely studied in the meat industry and lipid peroxidation research due to its implications for food quality and safety. Current methods for quantifying MDA in solid tissues are labor-intensive, requiring multiple instruments and approximately two hours to complete. This study presents an ultrafast kinetic fluorogenic method for quantifying MDA in ground beef, utilizing 2-thiobarbituric acid (TBA) as a fluorogenic probe. The total assay time is significantly shortened to 6 min from sample preparation to data acquisition. The assay’s robustness against matrix interference was validated using sample volume variation and standard addition calibration methods. Additionally, the effects of ambient exposure to air, washing, and cooking on MDA content in raw ground beef were quantified. While both ambient exposure to air and cooking increased MDA levels, washing raw ground beef and decanting cooked ground beef broth effectively reduced MDA levels in the ground beef. This simple and rapid assay can be adopted both in food research and industry. Moreover, insights from our study on the relationship between ground beef treatment and MDA concentration will help consumers make informed decisions about ground beef handling and consumption to lower their intake of MDA.

Industrial hemp (Cannabis sativa L.) is an attractive candidate for sustainable pest management due to its abundance of bioactive compounds with potential pesticidal properties. Solvent choice has a significant impact on the extraction efficiency of bioactive compounds. Deep Eutectic Solvents (DESs) are gaining popularity in extraction because they are safe and environmentally friendly, making them viable alternatives to organic solvents (OSs). This research first compared the extraction efficiency of OSs in the extraction of phytochemicals from the infloresences of two hemp varieties, Citrus and Cherry Dwarf. Inflorescences were extracted using three OSs, ethanol, ethyl acetate, and hexane. The highest level of cannabidiol (CBD; 0.69%) was extracted from Cherry Dwarf using ethanol, while the level of delta-9 tetrahydrocannabinol THC (0.19%) was essentially the same in both. Therefore, Cherry Dwarf was selected to compare the extraction efficiency of DESs with OSs. The DESs were choline chloride/ethylene glycol, citric acid/ethylene glycol, menthol/lauric acid, choline chloride/urea, and choline chloride/glycerol. In the targeted analysis, choline chloride/ethylene glycol extracted the highest amount of CBD (0.87%) followed by choline chloride/urea (0.78%). As some DESs outperformed ethanol, the popular solvent for extracting cannabinoids, DESs are viable candidates for replacement of organic solvents.

Pests and diseases have caused significant problems since the domestication of crops, resulting in economic loss and hunger. To overcome these problems, synthetic pesticides were developed to control pests; however, there are significant detrimental side effects of synthetic pesticides on the environment and human health. There is an urgent need to develop safer and more sustainable pesticides. Industrial hemp is a reservoir of compounds that could potentially replace some synthetic bactericides, fungicides, and insecticides. We determined the efficacy of industrial hemp extracts against Pseudomonas syringae pv. tabaci (PSTA), Pseudomonas syringae pv. tomato (PSTO), and Erwinia carotovora (EC). The study revealed a minimum inhibitory concentration (MIC) of 2.05 mg/mL and a non-inhibitory concentration (NIC) of 1.2 mg/mL for PSTA, an MIC of 5.7 mg/mL and NIC of 0.66 mg/mL for PSTO, and an MIC of 12.04 mg/mL and NIC of 5.4 mg/mL for EC. Time-kill assays indicated the regrowth of E. carotovora at 4 × MIC after 15 h and P. syringae pv. tomato at 2 × MIC after 20 h; however, P. syringae pv. tabaci had no regrowth. The susceptibility of test bacteria to hemp extract can be ordered from the most susceptible to the least susceptible, as follows: P. syringae pv. tabaci > P. syringae pv. tomato > E. carotovora. Overall, the data indicate hemp extract is a potential source of sustainable and safe biopesticides against these major plant pathogens.

A new synthesis of N-fused tetracyclic indole derivatives and their related polycyclic analogues has been developed based on ruthenium-(II)-catalyzed C-H activation and intramolecular hydroarylation. A series of polycyclic indoles with a 3-formyl group have been prepared in good to high yields. Various aliphatic and aromatic amines have been studied to form a transient directing group with the aldehyde for the catalytic process. A significant impact of the structures of the aromatic amines was identified, and 1-naphthylamine was shown to enable the catalytic process. DFT computations were performed to gain further insight into the role of the transient directing groups.

The popular textbook and literature model I(λx,λm) = K(λx,λm)(1-10-Ax) or its variants for correlating the sample absorption and fluorescence often fails even for the simplest samples where the fluorophore is the only light absorber. Reported is a first-principle model I(λx,λm) = K(λx,λm)Ax,f10-(Ax,sdx+Am,sdm) for correlating the sample fluorescence measured with a conventional spectrofluorometer and its UV-vis absorbance quantified with a conventional UV-vis spectrophotometer. This model can be simplified or expanded for a variety of fluorescence analyses. First, it enables curve-fitting fluorescence intensity as a function of the fluorophore or sample absorbance over a sample concentration range impossible with existing models. Second, it provides the theoretical foundation for an inner-filter-effect (IFE)-correction method developed earlier and explains mathematically the linearity between the IFE-corrected fluorescence and the fluorophore concentration or absorbance. Third, this model can be expanded for quantitative mechanistic studies of fluorescence intensity variations triggered by stimuli treatments. One demonstrated example is to quantify temperature effects on the emission-wavelength-specific and total fluorescence quantum yield of anthracene. We expect that this first-principle model will be broadly adopted for both student education that promotes evidence-based learning and a variety of fluorescence applications where disentangling sample absorption and emission are critical for reliable data analysis.

Plant-parasitic nematodes (PPNs) are incredibly damaging pests, which cause significant losses in crop yields worldwide. One of the most prevalent PPNs is the root-knot nematode (Meloidogyne spp.) ranks number one on the most economically devastating list of pests and thus scientifically important PPNs. Recently, the use of chemical nematicides for root-knot nematode management has decreased due to governmental restrictions; which necessitates the development and identification of alternative pest management procedures.

Metabolite extraction is one of the critical steps in microbial metabolome analysis. It affects both the observed metabolite content and biological interpretation of the data. Several methods exist for metabolite extraction of microbes, but the literature is not consistent regarding the sample model, adequacy, and performance of each method. In this study, an optimal extraction protocol for Yersinia intracellular metabolites was investigated. The effect of five extraction protocols consisting of different extraction solvent systems (60% methanol, 100% methanol, acetonitrile/methanol/water (2:2:1), chloroform/methanol/water (2:1:1), and 60% ethanol) on Yersinia metabolic profiles were compared. The number of detected peaks, sample-to-sample variation, and metabolite yield were used as criteria. Extracted metabolites were analyzed by 1H-NMR and principal component analysis (PCA), as well as partial least squares discriminant analysis (PLS-DA) multivariate statistics. The extraction protocol using 100% methanol as the extraction solvent provided the highest number of detected peaks for both Yersinia species analyzed, yielding more spectral information. Together with the reproducibility and spectrum quality, 100% methanol extraction was suitable for intracellular metabolite extraction from both species. However, depending on the metabolites of interest, other solvents might be more suitable for future studies, as distinct profiles were observed amongst the extraction methods.

The World Health Organization and the National Institute of Mental Health (United States of America) states that neurodegenerative diseases leads to significant loss of regular activity of the patients, their family and the caretakers leading to a huge economic loss. Current treatments provide modest and temporary symptomatic relief, without altering the underlying mechanisms associated with the onset and the progression of the neurodegenerative diseases. Strong scientific evidence points to the involvement of oxidative stress in the pathogenesis of neurodegenerative diseases. Thus, the current therapeutic efforts have been directed to find beneficial agents that could reduce the oxidative damage and promote a functional recovery of neurons in degenerative disorders. Hydrogen peroxide is an endogenous neurotoxin which can initiate and propagate (promote) neurodegeneration. Hibiscus sabdariffa (roselle) exhibits multiple pharmacological activities. Hence in this study, the authors evaluated the neuroprotective effects and the possible mechanisms of action of Hibiscus sabdariffa (roselle) against the hydrogen peroxide-induced neurotoxicity. Hibiscus sabdariffa exhibited antioxidant and antiapoptotic effects and significantly attenuated the neurotoxicity of hydrogen peroxide. Hibiscus sabdariffa exhibits neuroprotective effects and can be an effective and novel alternative approach to reduce the risk of various neurodegenerative disorders.

Introduction: Neurogenic hypertension is characterized by increased blood pressure, neuroinflammation, and neuronal oxidative stress. Thus, its pathophysiology dictates a unique therapeutic strategy. It is established that Hibiscus sabdariffa (HS) plays a beneficial role in decreasing blood pressure, yet the role of HS as an anti-oxidant defense system in neurogenic hypertension has not been investigated. Our objective was to generate an in vitro model of neuronal oxidative stress to test the hypothesis that HS creates a neuroprotective antioxidant defense system. Methods: To create a model of oxidative stress, SY5Y, neuroblastoma cells, were treated with 32uM hydrogen peroxide. To determine the effect of methanol-extracted HSE (50 and 100ug n ≥ 8) in this model of oxidative stress, SY5Y cells were treated with vehicle-PBS, HSE (24hrs), pretreated with HSE (24hrs) and then treated with H2O2 (8hrs). Using molecular techniques markers of oxidative stress were measured and percentages were out of 100. Data was normalized to the control and analyzed by one way ANOVA (p value < .05 was considered significant). Results: HSE significantly increases cell viability (50 or 100ug > 99%) compared to H2O2 alone (43%). HSE significantly decreases ROS generation (113%-50ug versus 89%-100ug) compared to H2O2 (120%). HSE significantly decreases lipid peroxidation (11.3%-50ug versus 10.2%-100ug) compared to H2O2 (135%). HSE significantly increases GSH content (72%-50ug versus 91%-100ug) compared to H2O2 (58%). HSE significantly increases catalase activity (31%-50ug versus 51%,-100ug) compared to H2O2 (23%). HSE significantly increases mitochondrial complex 1 activity (125%-50ug versus 229%-100ug) compared to H2O2 (26.2%). There was no significant change in superoxide dismutase activity amongst groups. Conclusion: These observations suggest that HSE creates an antioxidant defense system that provides cytoprotection against H2O2-induced neuronal oxidative stress. Thus, HS, a known anti-hypertensive should be revisited to investigate its in vivo role in neurogenic hypertension.

The nucleus independent chemical shift (NICS) criterion of aromaticity is used to evaluate the aromaticity of a series of poly-2,7-[N]calicenes. The geometry and NICS values of all poly-2,7-[N]calicenes and reference molecules (calicene, bicalicene, benzene, cyclopentadienyl anion and cyclopropenyl cation) are evaluated at the B3LYP/6-31G(d,p) level of computational theory. The NICS data indicate that all poly-2,7-[N]calicenes studied are aromatic, and aromaticity increases as the number of calicene units (N) increases.

Studies of protein and organothiol interactions with silver nanoparticles (AgNPs) are important for understanding AgNP nanotoxicity, antimicrobial activity, and material fabrications. Reported herein is a systematic investigation of the effects of both reduced and oxidized protein cysteine residues on protein interactions with AgNPs. The model proteins included wild-type and mutated protein GB3 variants that contain 0, 1, or 2 reduced cysteine residues, respectively. Bovine serum albumin (BSA) that contains a total of 34 oxidized (disulfide-linked) cysteine residues and one reduced cysteine residue was also included. Protein cysteine content has no detectable effect on the kinetics of protein/AgNP binding. However, only proteins that contain reduced cysteine residues induce significant AgNP dissolution. Proteins can slow down, but do not prevent the AgNP dissolution induced by subsequently added organothiols. The insights provided in this work are important to the mechanistic understanding of AgNP stability in biofluids that are rich in proteins and amino acid thiols.

Using propanethiol (PrT), 2-mercaptoethanol (ME), glutathione (GSH), and cysteine (Cys) as model thiols, we demonstrated herein that organothiols can induce both silver nanoparticle (AgNP) disintegration and formation under ambient conditions by simply mixing organothiols with AgNPs and AgNO3, respectively. Mechanistically, organothiols induce AgNP disintegration by chelating silver ions produced by ambient oxygen oxidizing the AgNPs, while AgNP formation in AgNO3/organothiol mixtures is the result of organothiols serving as the reducing agent. Furthermore, surface-plasmon- and fluorescent-active AgNPs can be interconverted by adding excess Ag+ or ME into the AgNP-containing solutions. Organothiols can also reduce gold ion in HAuCl4/organothiol solutions into fluorescence- and surface-plasmon-active gold nanoparticles (AuNPs), but no AuNP disintegration occurs in the AuNP/organothiol solutions. This work highlights the extraordinary complexity of organothiol interactions with gold and silver nanoparticles. The insights from this work will be important for AgNP and AuNP synthesis and applications.

Previous researchers proposed that thiolated poly(ethylene glycol) (PEG-SH) adopts a "mushroom-like" conformation on gold nanoparticles (AuNPs) in water. However, information regarding the size and permeability of the PEG-SH mushroom caps and surface area passivated by the PEG-SH mushroom stems are unavailable. Reported herein is our finding that AuNPs that are covered by saturation packed PEG-SHs all have large fractions of AuNP surface area available for ligand adsorption and exchange. The model ligands adenine and 2-mercaptobenzimidazole (2-MBI) can rapidly penetrate the PEG-SH overlayer and adsorb onto the AuNP surface. Most of the ligand adsorption and exchange occurs within the first minutes of the ligand addition. The fraction of AuNP surface area passivated by saturation packed model PEG-SHs are similar to 25%, similar to 20%, and similar to 9% for PEG-SHs with molecular weights of 2000, 5000, and 30 000 g/mol, respectively. Localized surface plasmonic resonance and dynamic light scattering show that the PEG-SH overlayer is drastically more loosely packed than the protein bovine serum albumin on AuNPs. Studies investigating the effect of aging the AuNP/PEG-SH mixtures on subsequent adenine adsorption onto the pegylated AuNPs revealed that PEG-SHs reach approximately a steady-state binding on AuNPs within 3 h of sample incubation. This work sheds new insights into the kinetics, structures, and conformations of PEG-SHs on AuNPs and demonstrates that pegylated AuNPs can be used as an important platform for studying ligand interaction with AuNPs. In addition, it also opens a new avenue for fabrication of multicomponent functionalized nanoparticles.

Dispersion stability, ligand structure and conformation, and SERS activities of 1-alkanethiol (CnH2n+1SH, n = 214) functionalized gold and silver nanoparticles (AuNPs and AgNPs) were studied as a function of alkanethiol carbon chain length and nanoparticle (NP) type and size. The dispersion stability of alkanethiol functionalized NPs in water increases with increasing alkanethiol chain length and NP size, and the stabilities of the alkanethiol-containing AuNPs are higher than their AgNP counterparts. C3H7SH and longer alkanethiols are highly ordered on AgNPs but disordered on AuNPs. The SERS intensity of the CS stretch band for the model alkanethiols on AgNPs and AuNPs decays exponentially (I = I-0 exp(-N-c/N-0)) with increasing number of carbon atoms (N-c). The empirical decay length N0, in terms of the number of the carbon atoms, is 1.29, 0.53, and 0.10 for AgNPs with diameters of 50, 30, and 10 nm, respectively. This decay length is less than 1 for AuNPs of difference sizes. These results show that changing the NP gap size by a distance equivalent to a single chemical bond can have a significant impact on the NP integrated SERS activities.