Chemical Perspective Research Articles

Exploring the impact of elevated pH and short maceration on the deterioration of red wines: physical and chemical perspectives

This study explored the impact of high pH and short maceration on red wines' physical and chemical traits and stability. Specifically, wines from Petit verdot, Merlot, Malbec and Tempranillo grapes, harvested in a tropical wine-producing region, were analysed. A consistent maceration period of 96 hours was applied in all vinification trials. After six months of bottling, parameters such as colour, acetaldehyde levels, higher alcohols and phenolic compounds were assessed. The findings highlighted significant impacts of grape pH on chemical stability, influenced by the phenolic profile of each grape variety. The short maceration period reduced phenolic compound extraction in high-pH musts, leading to decreased antioxidant potential and chemical stability. Critical indicators included colorimetric parameters, acetaldehyde and free SO₂ content. Acetaldehyde levels were strongly correlated with free SO₂ consumption and colour variations, signifying oxidative processes. Wines with higher concentrations of (+)-catechin, procyanidins and monomeric anthocyanins exhibited enhanced stability, while the presence of hydroxycinnamic acids was associated with oxidative changes. Caffeic acid emerged as a potential marker of oxidative stress, particularly in grapes from warmer climates. To improve the stability of wines made from high-pH grapes, extended maceration times or increased SO₂ dosages may be required.

Colloidal High Entropy Alloy Nanoparticles: Synthetic Strategies and Electrocatalytic Properties.

High entropy alloy (HEA) nanoparticles (NPs) have attracted much attention recently due to their unprecedented chemical properties. As such, HEA NPs have been used as materials with superior activity toward electrocatalytic applications. Specifically, solid solutions that form randomly mixed single-phased structures have received the most focus in the early stages of HEA NP development for their entropic-driven design and multifunctionality. Advances to non-colloidal and colloidal synthetic methods have allowed for the fabrication of solid solution HEA NPs with varying compositions and complexity to be applied to many practical applications such as fuel cells, energy storage and agriculture. In this review, the current colloidal methods and catalytic mechanisms for solid solution HEA NP synthesis are investigated from the physical chemistry perspective. A comprehensive discussion on the theory, techniques, and electrocatalytic applications of colloidal syntheses for successful solid solution HEA NP formation is presented. Finally, promising perspectives for the continued development of physical insights into structure-property relationships towards improved HEA NP synthesis and application are discussed.

The Role of Chemistry in Achieving Sustainable Development Goals: Green Chemistry Perspective

The Role of Chemistry in Achieving Sustainable Development Goals: Green Chemistry Perspective

A Review of Sources, Hazards, and Removal Methods of Microplastics in the Environment

The prevalence of microplastics in a wide range of environmental media has attracted increasing attention worldwide. This review article provides a comprehensive and systematic review of the nature, sources, hazards, and removal methods of microplastics in the environment. In contrast to previous studies focusing on the sources and risks of microplastics in a single environment, this article comprehensively analyses atmospheric, terrestrial runoff, marine and freshwater sources of microplastics and explores the hazards they pose to the environment and the health of humans and other organisms. Microplastics cause multiple adverse effects on aquatic and terrestrial organisms through accumulation, including growth inhibition, oxidative stress, inflammation, organ damage, and germ cell abnormalities. They may also enter the food chain and affect human health. This article summarizes the latest research progress on microplastic removal technologies from biological, physical, and chemical perspectives, with high efficiency, sustainability, and degradability for biological removal and adsorption and filtration being more effective for physical removal. This provides valuable information for future research related to microplastics. We advocate for a reduction in the use of microplastics and provide references for solving the problem of microplastic pollution.

Investigating the Formation of Trace Metal Contamination in Insulating Oil: From Electrical Erosion and Chemical Corrosion Perspectives

Investigating the Formation of Trace Metal Contamination in Insulating Oil: From Electrical Erosion and Chemical Corrosion Perspectives

Monitoring of milk rennet coagulation: chemical and physical perspective using Raman spectroscopy

Monitoring of milk rennet coagulation: chemical and physical perspective using Raman spectroscopy

A Collection of Novel Antitumor Agents That Regulate Lipid Metabolism in the Tumor Microenvironment.

Lipid metabolism disorder is the cause of one of the most significant metabolic changes in tumors. In the process of tumor occurrence and development, tumor cells choose a continuous metabolic adaptation to accommodate the changing environment to the maximum extent possible. In a variety of tumors, the uptake, production, and storage of lipids are generally upregulated. Tumor cells take advantage of lipid metabolism to access basic energy, biofilm components, and signal molecules of the tumor microenvironment required for proliferation, survival, invasion, and metastasis. This Perspective briefly uncovers the main metabolic processes and key factors involved in lipid metabolism reprogramming, mainly related to lipid uptake, de novo synthesis and storage of fatty acids, oxidation of fatty acids, cholesterol synthesis, and related regulatory factors. From a medicinal chemistry perspective, agents against related key targets are reviewed, expecting to pave the way for promising antitumor drugs with prospects for application through lipid metabolism reprogramming.

An Interdisciplinary Approach in Integrated Science Studies: Using Webbed Models to Understand Biotechnology Content

This article discusses the application of an interdisciplinary approach in the study of biotechnology through webbed models. By integrating concepts from different disciplines such as biology, chemistry, and physics, this model allows for a more holistic understanding of complex interactions in biotechnology processes. This research highlights the content of biotechnology that can be discussed integratively, including aspects of metabolism and microorganisms in fermentation processes from a biological perspective, Maillard reactions and acid-base salts from a chemical perspective, and heat transfer and diffusion from a physics perspective. In addition to the challenges of interdisciplinary communication, this article also identifies opportunities that can be leveraged through information and communication technology to support collaboration. It is hoped that this approach can improve students' skills and prepare them to face the complexities of the ever-evolving world of biotechnology.

Unraveling the mechanism: How does β-phosphoglucomutase from the haloacid dehalogenase superfamily catalyze the interconversion of β-d-glucose 1-phosphate and β-d-glucose 6-phosphate? A chemical perspective

The catalytic mechanisms of enzymes can be phylogenetically mapped corresponding to their catalytic structures. This mapping effectively elucidates the diversity of enzyme catalytic mechanisms and the emergence of new enzymatic activities within enzyme superfamilies. The haloacid dehalogenase (HAD) superfamily serves as an exemplary model system for comprehending the co-evolution of catalytic structures and mechanisms. This study delves into the mechanism underlying the functional divergence of β-phosphoglucomutase (β-PGM) from the phosphatase branch of the HAD superfamily, employing a chemical perspective. Through the construction and calculation of three models of varying scales using the Density Functional Theory method with B3LYP function, we aim to investigate the chemical mechanism driving this functional divergence of β-PGM from the HAD family. The computational results indicate that residues His20 and Lys76 in the second shell stabilize substrates and enhance the acid-base catalytic ability of Asp10. Additionally, residues Arg49, Ser116 and Asn118 facilitate substrate binding by engaging in close hydrogen bonding interactions with the substrates. Through cooperative action, these residues enable β-PGM to function as an efficient phosphoglucomutase. Through computational modeling and a chemical perspective, we unravel the mechanisms enabling β-PGM to convert β-d-glucose 1-phosphate to β-d-glucose 6-phosphate. Finally, based on the analysis of the evolutionary tree, we discussed and summarized the evolutionary relationships among different forms of metal cores of hydrolases.

Hydroxylase-oriented mining and functional characterization of camptothecin 10-hydroxylase from Camptotheca acuminata Decne

The regiospecific C-10 hydroxylation of camptothecin (CPT) is challenging from a chemical perspective. This step bridges the natural-sourced CPT to an important industrial material, 10-hydroxycamptothecin (10HCPT). 10HCPT is naturally generated in a medicinal plant, Camptotheca acuminata Decne. Functionally active hydroxylase responsible for regiospecific C-10 hydroxylation of CPT is undoubtedly existed in this plant. Therefore, the multi-omics database of C. acuminata was utilized to perform hydroxylase-oriented mining and screening. Three CYP81 genes were identified and two of them, including CYP81BQ18 and CYP81B256 catalyzed hydroxylation of CPT at the C-10 position. CYP81B256 and CYP81BN24 displayed quercetin C-5’ hydroxylase activity. CYP81B256 exhibited better catalytic performance for CPT than CYP81BQ18 and CPT10H in vitro. Furthermore, CYP81BQ18 and CYP81B256 displayed CPT 10-hydroxylase activity in tobacco. Functional verification in planta suggested that the newly observed CYP81BQ18 and CYP81B256 were involved in 10HCPT biosynthesis in C. acuminata. Subcellular localization analysis revealed that these CYP81 genes were located on the endoplasmic reticulum. Evolutionary analysis indicated that CYP81B256 and CYP81BN24 probably evolved from a same ancestral gene via gene duplication, while CYP81BQ18 evolved independently and acted as a specie-specific hydroxylase. CYP81B256 acted as an evolutionary intermediate gene bridging the alkaloid and flavonoid metabolism in C. acuminata. This research provides valuable insights into the function and evolutionary origin of CYP81s in the regiospecific hydroxylation step for 10HCPT biosynthesis.

Chemical perspective on radionuclide emissions as atmospheric contaminants from nuclear reactors

This study investigates the radionuclide emissions from nuclear power plants (NPPs), focusing on the gas-aerosol emissions from reactors such as VVER-440. The radionuclide composition of these emissions is analysed to determine the biological hazards they pose, particularly focusing on isotopes such as tritium and radiocarbon. The research highlights the patterns of radionuclide accumulation in fuel assemblies using "rank-size" coordinates, which provide a more visual and informative method compared to traditional atomic weight dependency analyses. The study introduces the Zipf-Mandelbrot type rank distributions and proposes that the emissions can be effectively monitored by measuring only a few key radionuclides, thereby simplifying the process. This method is validated across different reactor types, indicating its broad applicability. The research underscores the potential of using these patterns for more efficient regulation and control of radionuclide emissions from NPPs.

Evaluation of 1064 nm Raman for meat and bone meal species discrimination: From raw form to chemical and physical components

The 1064 nm Raman spectroscopy technique was employed to characterize raw, bone fragments (BF), meat fragments (MF), lipid, and residue of meat and bone meal (MBM) samples. Employing three chemometric algorithms, species discrimination models were optimized for the aforementioned sample types, indicating that the presence of BF favored discriminant analysis for poultry samples, yielding a classification error of 0.000. The species discrimination model constructed using Raman spectra combined with PLS-DA algorithm for residue samples was found to be overall optimal, with classification error for four species samples all below 0.061. A detailed analysis of the BF related spectral variables contributing significantly to PLS-DA discriminant analysis was conducted. Finally, this study established the complementarity of Raman spectroscopy in species discrimination analysis from both a physical and chemical components perspective, laying the theoretical groundwork for the development of a high-precision 1064 nm Raman spectroscopic analysis method for MBM species discrimination.

Load Cycling Durability Protocols for Predictive MEA Lifetime Modeling for Long-Life PEMFC Applications

As the large-scale commercialization of proton exchange membrane fuel cells (PEMFC) for numerous heavy-duty applications draws nearer, there is an increasing emphasis on the delivery of highly robust membrane electrode assemblies (MEAs) capable of achieving upwards of 25,000 hours of on-road durability (1). A particular area of MEA durability focus is that of the proton conducting perfluorosulfonic acid (PFSA) membrane which is subjected to varying degrees of oxidative stress during fuel cell operation. The development of highly durable membranes necessitates the implementation of accelerated testing protocols that can be used to determine the sensitivity of membrane lifetime to a number of operational parameters such as cell temperature and membrane humidification. The objective of sensitivity studies is to develop robust and predictive degradation models using state-of-the-art (SOA) MEAs under the accelerated operational space that can be subsequently applied to the milder operational space of a long-lifetime application. Traditionally, open circuit voltage (OCV) degradation studies have been employed to assess membrane durability. While OCV degradation experiments can be highly accelerating from a chemical degradation perspective, producing high fluoride release and membrane thinning rates, the operating conditions do not sufficiently emulate the dynamic chemical stresses generated under load nor do they provide RH cycling and concomitant mechanical stresses that accompanies load cycling (2). At the other end of the cell load continuum, constant current durability tests have consistently failed to produce high degradation rates, even in the presence of Fe accelerants.In response to the recognized shortcomings of OCV and related accelerated durability tests, we have developed a suite of flexible, single-cell, load-cycling durability tests that more closely emulate stresses experienced in variety of real-world, on-load applications. Test protocols enable the variation numerous operational parameters including temperature, inlet RH, high and low cycling current densities and the ratio of time spent at the high and low current densities. In-situ degradation rates are assessed by monitoring emitted fluoride concentrations at regular intervals. Cerium-mitigated (3), SOA PFSA membranes fabricated with PtCo/HSC cathode electrodes are quite robust even under the harshest load cycling conditions (110 °C/ 30% RH), producing fluoride release rate (FRR) values less than 1x10-8 gF/cm-2h-1. The creation of predictive chemical degradation models requires significant and quantifiable chemical degradation signals to occur across accelerated the reaction space continuum. Therefore, given the high stability of SOA membranes, the degradation rates are further accelerated by the addition of Fe2+ Fenton’s catalysts. The Figure below shows the FRR profiles obtained from a series of four MEAs, differing only in the amount of added Fe2+ prior to the durability test conducted at 95 °C/30% RH with load cycling between 0.02-1.5 A/cm². In addition to Fe sensitivity findings, we will present data regarding sensitivities of degradation rates with respect to temperature, inlet RH, high current density values and time ratios at high and low current densities.(1) D. A. Cullen, K. C. Neyerlin, R. K. Ahluwalia, R. Mukundan, K. L. More, R. L. Borup, A. Z. Weber, D. J. Myers, A. Kusoglu, Nature Energy, 6, 462–474 (2021)(2) C. S. Gittleman, F. D. Coms, Y.-H. Lai, In Polymer Electrolyte Fuel Cell Degradation, M. Matthew, K. E. Caglan, T. N. Veziroglu, Editors, p. 15, Academic Press, Boston (2012)(3) F. D. Coms, H. Liu, and J. E. Owejan, ECS Transactions, 16, 1735 (2008) Figure 1

Thermal Stability and Performance of Li-Ion Batteries at Elevated Temperatures: Separator Effects

The performance and safety of lithium-ion batteries (LIBs) are significantly influenced by the stability and integrity of their components that have been optimized for a limited temperature range (ca. 0 to 40°C). At elevated temperatures, conventional LIBs exhibit issues such as rapid capacity fade, compromised electrolyte stability, and an increase in internal resistances. With the push towards net-zero emissions, it is imperative that suitable materials and cell designs be identified to allow rechargeable battery integration into operations with temperatures as high as 100°C for applications such as space exploration, drilling equipment, and automotive technologies.In our presentation, we will report that a design of experiment (DOE) study examining several independent variables and interactions of variables in the cell design revealed that the standard polyolefin separator is associated with both decreased Coulombic efficiency and increased variability in cycling performance at elevated temperatures relative to non-polyolefin (e.g. polyimide) separators. In a separate study, electrochemical data were obtained by cycling coin cells at 100oC, varying only the separator (Fig. 1). After the first 20 cycles, the polyimide cells maintained a higher specific capacity relative to the polyolefin cells. Figure 1. Specific capacity vs. cycle number for NMC111/graphite coin cells with Polyimide and Polyolefin separatorsThe nature of the separator alterations from a chemical and electrochemical perspective will be presented, which will provide valuable insight into the critical role of separators in battery design while simultaneously offering alternative materials for operations as high as 100°C. Figure 1

Data Quality in the Fitting of Approximate Models: A Computational Chemistry Perspective.

Empirical parametrization underpins many scientific methodologies including certain quantum-chemistry protocols [e.g., density functional theory (DFT), machine-learning (ML) models]. In some cases, the fitting requires a large amount of data, necessitating the use of data obtained using low-cost, and thus low-quality, means. Here we examine the effect of using low-quality data on the resulting method in the context of DFT methods. We use multiple G2/97 data sets of different qualities to fit the DFT-type methods. Encouragingly, this fitting can tolerate a relatively large proportion of low-quality fitting data, which may be attributed to the physical foundations of the DFT models and the use of a modest number of parameters. Further examination using "ML-quality" data shows that adding a large amount of low-quality data to a small number of high-quality ones may not offer tangible benefits. On the other hand, when the high-quality data is limited in scope, diversification by a modest amount of low-quality data improves the performance. Quantitatively, for parametrizing DFT (and perhaps also quantum-chemistry ML models), caution should be taken when more than 50% of the fitting set contains questionable data, and that the average error of the full set is more than 20 kJ mol-1. One may also follow the recently proposed transferability principles to ensure diversity in the fitting set.

Opportunities and Challenges of Arginase Inhibitors in Cancer: A Medicinal Chemistry Perspective.

The overexpression of two arginase (ARG) isoforms, ARG1 and ARG2, contributes to the onset of numerous disorders, including cardiovascular and immune-mediated diseases, as well as tumors. To elucidate the specific roles of ARG1 and ARG2 without interfering with their physiological functions, it is crucial to develop effective ARG inhibitors that target only one isoform, while maintaining low toxicity and an adequate pharmacokinetic profile. In this context, we present a comprehensive overview of the different generations of ARG inhibitors. Given the general lack of selectivity in most existing inhibitors, we analyzed the structural features and plasticity of the ARG1 and ARG2 binding sites to explore the potential for designing inhibitors with novel binding patterns. We also review ongoing preclinical and clinical studies on selected inhibitors, highlighting both progress and challenges in developing potent, selective ARG inhibitors. Furthermore, we discuss medicinal chemistry strategies that may accelerate the discovery of selective ARG inhibitors.

Pyroelectrically Driven Charge Transfer and its Advantages on SERS and Self‐Cleaning Property

AbstractThe fabrication of reusable SERS substrates with sensitivity at the single‐molecule level remains challenging but promising. Herein, a composite surface‐enhanced Raman scattering (SERS) substrate is proposed that includes Ag nanoparticle (Ag NPs) /Graphene/BaTiO3 (Ag/G/BTO) from a chemical enhancement perspective. The pyroelectric field generated by BaTiO3 drives the charge transfer between the SERS substrate and molecules, achieving a significant improvement in the SERS performance and self‐cleaning properties. The SERS signals of rhodamine 6G (R6G) molecules are further amplified up to 70‐fold. Thus, the detection limit is reduced by three orders of magnitude in this study, reaching 10−14 m after applying a pyroelectric field. In addition, the substrate exhibits a higher degradation efficiency than previous self‐cleaning SERS substrates because of the outstanding catalytic properties of BaTiO3. Target molecules are degraded effectively after several temperature cycles. A detailed mechanism analysis of pyroelectric SERS is conducted based on theoretical simulations and experimental results. This study is considered to deepen the understanding of SERS mechanisms and boost the application of SERS technology.

The Death of the Strategy of Classical Chiral Switches Is an Exaggeration.

The strategy of classical chiral switches of drugs is still alive, contrary to a 2024 Journal of Medicinal Chemistry Perspective on approved chiral drugs claiming its death. Surveys of approved chiral-switch and racemic drugs should be based on reports of global regulatory authorities, not just FDA and EMA, which revealed overlooked chiral switches and racemates. The approved antihypertensive racemate nebivolol indicates the synergy between its enantiomers, highlighting the advocacy of developing racemic drugs.

Mechanism and optimization of sintered ultra-lightweight aggregates with sand washing slurry and red mud

Sand washing slurry, red mud, and waste sawdust are major solid wastes produced by the construction, mining, and wood processing industries, respectively. Their accumulation poses significant environmental hazards and results in substantial wastage of resources. This study utilized a novel rapid roasting method to prepare ultra-lightweight ceramsite aggregates (ULC) using sand washing slurry, red mud, and sawdust as raw materials. A new process for preparing ultra-lightweight clay aggregates (ULCA) utilizing waste sand washing sludge is proposed, achieving a utilization rate of the wash sand sludge exceeding 60%. Ultra-lightweight clay aggregates with a loose bulk density of 264.3 kg/m3 were produced. The influence of material formulation on the performance of ultra-lightweight clay aggregates was studied. The phase changes and expansion mechanism of the clay aggregates were revealed from microscopic and chemical perspectives. The synergistic effect of red mud and sawdust significantly enhanced the foaming effect of the ceramsite (i.e., porosity), reducing its loose bulk density while slowing the rate of strength reduction. Additionally, increasing the content of red mud and sawdust promoted ceramsite expansion. When the mass ratio of sand washing slurry, red mud, and sawdust was 29: 12: 1, with Fe2O3 content at 13% and sawdust content at 3%, preheating at 500°C for 5 minutes followed by roasting at 1150°C for 5 minutes produced ultra-lightweight ceramsite with a compressive strength of 1.7 MPa. This study provides a promising method for producing ULC from industrial solid wastes.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.