Hasil untuk "Physical and theoretical chemistry"

J. Pople, M. Gordon

Jan Leja

Ge Feng

Ahmad Ghanbari

Andrea Gutiérrez-García, Francisco Javier Olivas-Aguirre, Miguel Olivas-Aguirre

Adipocyte cell models are essential for investigating adipogenesis, yet methodological inconsistencies pose challenges to obtaining reproducible and physiologically relevant results. Murine cell lines, such as 3T3-L1 and OP9, are commonly utilized due to their established adipogenic capabilities. However, differences in its metabolic, genetic regulation, and receptor signaling raise concerns about their applicability to human adipose biology. Human-derived models, including mesenchymal stem cells (hMSCs) and preadipocyte cell lines, offer a closer approximation to in vivo adipogenesis but display significant variability in differentiation efficiency. This variability is often compounded by heterogeneous differentiation protocols, variations in cell confluence, and unstandardized pharmacological induction strategies. A pivotal factor influencing adipogenic potential is the receptor toolkit, which dictates cellular responses to differentiation stimuli. This study systematically evaluates key receptors—PPARγ, glucocorticoid receptors (GR), insulin receptor (IR), thyroid hormone receptors (TR), estrogen receptors (ER), and adenosine receptors (AR)—across commonly used adipocyte models to assess their roles in adipogenic regulation. Additionally, we examine the impact of pharmacological agents capable of inducing adipogenesis (adipogens) and the methodological inconsistencies that contribute to variations in adipocyte differentiation. By addressing these factors, we aim to elucidate the extent to which receptor variability influences experimental outcomes and propose a more structured approach to interpreting adipogenesis research. This critical assessment underscores the need for greater methodological transparency and receptor profiling to enhance the reliability of adipocyte models in metabolic research. Standardizing differentiation methodologies while accounting for receptor diversity will be essential for refining in vitro models and improving their translational potential in the study of obesity, diabetes, and other metabolic disorders.

Dhilipkumar Thulasidhas, Sadeq Abdellatif M., Shankar Karthik V. et al.

Victor Kostjukov

ABSTRACTMN15/6‐31++G(d,p)/IEFPCM theory level gave a good agreement between the calculated vibronic and experimental absorption spectra of the dianion, in both the maximum position and the shape. Vibronic transitions of the dianion activate only two motions in the S1 state, namely, torsional vibrations of two aromatic rings (A and B) and the SO3 group attached to the third ring. Significant photoinduced distortions of the spatial structure of the anion (A and B rings, being almost parallel to each other in the ground state, become mutually perpendicular in the excited state) led to a failure of the Franck‐Condon computational procedure for calculating its vibronic spectrum. Photo‐induced shifts of the electron density are analyzed. The ring with the SO3 group attached is not involved in these charge redistributions for both the dianion and the anion. The negative solvatochromism of the dianion and the positive one of the anion observed experimentally were explained both from the point of view of non‐specific dipole–dipole interactions with the solvent (changes in the dipole moments of the solutes upon excitation) and specific ones (strengthening/weakening of strong hydrogen bonds of the dianion and anion with water molecules).

Akari Nishi, Azumi Hirata, Atsushi Mukaiyama et al.

A special type of <i>Streptococcus mutans</i> expressing collagen-binding proteins (CBPs), Cnm, and Cbm, on the cell surface has been shown to be highly pathogenic. It is believed that <i>S. mutans</i> with CBPs that has entered the blood vessel attaches to collagen molecules exposed from the damaged blood vessel, inhibiting aggregation by platelets and increasing bleeding. Therefore, it is crucial to understand the molecular characteristic features of CBPs to protect against and cure <i>S. mutans</i>-related diseases. In this work, we highlighted the Cbm/collagen-binding domain (CBD) and examined its binding ability and thermal stability using its domain/region exchange variants in more detail. The CBD comprises the N1-domain, a linker, N2-domain, and a latch (N1–N2~), where the latch interacts with the N1-domain to form a β-sheet. The collagen-binding activity of the Cbm/CBD domain/region exchange variants was investigated using ELISA. Binding assays demonstrated that the N-domain_linker_N-domain composition is necessary for collagen binding as previously reported, newly that the latch is involved in binding through the β-sheet with the N1-domain when the N1-domain is present at the N-terminal position, and that the N2-domain is particularly important for collagen binding at both the N- and C-terminal positions. Thermal denaturation experiments newly revealed that the linker and latch bound to the N-domain contribute to N-domain stabilization but have no effect on the N-domain_linker_N-domain molecule, which contains two N-domains. It has also been shown that the N-terminal N2-domain destabilizes the N-domain_linker_N-domain structure. The results of this study will contribute to the rapid detection of CBP, development of CBP-targeted therapies, and application of CBPs to protein engineering using their collagen-binding ability.

Henu Sharma, Aqsa Nazir, Arvind Kasbe et al.

Since the discovery of batteries in the 1800s, their fascinating physical and chemical pro­perties have led to much research on their synthesis and manufacturing. Though lithium-ion batteries have been crucial for civilization, they can still not meet all the growing demands for energy storage because of the geographical distribution of lithium resources and the intrinsic limitations in the cell energy density, performance, and reliability issues. As a result, non-Li-ion batteries are becoming increasingly popular alternatives. Designing novel materials with desired properties is crucial for a quicker transition to the green energy ecosystem. Na, K, Mg, Zn, Al ion, etc. batteries are considered the most alluring and promising. This article covers all these Li, non-Li, and metal-air cell chemistries. Recently, com­putational screening has proven to be an effective tool to accelerate the discovery of active materials for all these cell types. First-principles methods such as density functional theory, molecular dynamics, and Monte Carlo simulations have become established techni­ques for the preliminary, theoretical analysis of battery systems. These computational methods generate a wealth of data that might be immensely useful in the training and vali­dating of artificial intelligence and machine learning techniques to reduce the time and capital expenditure needed for discovering advanced materials and final product develop­ment. This review aims to summarize the application of these techniques and the recent deve­lopments in computational methods to discover and develop advanced battery chemistries.

Adsorption Science and Technology

S.Yu. Menshikov, A.N. Malyshev, V.S. Kurmacheva et al.

The catalytic properties of FeSO4, nanocluster ferro-molybdenum polyoxometalate {Mo72Fe30} and nanocluster molybdenum polyoxometalate {Mo132} have been studied during the oxidation of phenol in ethanol-isobutanol solution with persulfate. To determine the oxidation products, phenol, ethanol and isobutanol of an acidic nature, sulfonic cation exchanger KU-2 (the grade of ion exchange resin established by the state standard of the Russian Federation GOST 20298-74) was added to the reaction mixture in each experiment to catalyze the esterification reaction of acid oxidation products with the initial alcohols. Acid esterification products were identified by the vapor-phase chromatography method with a mass spectroscopic detector. According to the conversion of phenol, ethanol and isobutanol, the catalytic properties of a homogeneous FeSO4 catalyst (similar to Fenton's reagent) with heterogeneous catalysts (polyoxometalates) were compared. These data suggest the possibility of further searching for heterogeneous catalysts containing Fe and Mo in their composition during the destruction of phenol by peroxide compounds.

Hui Fang, Jianing Zhao, Ki Jun Yu et al.

Ting Luo, Jian-Guo Jiang

Black tea is one of the most popular beverages in the world, and numerous epidemiological studies have shown that drinking black tea is good for health. As a natural tea pigment formed during the fermentation of black tea, the content of theaflavins accounts for only 2-6% of the dry weight of black tea, but they have a great impact on the color and taste of black tea soup. Recently, a large number of studies have shown that theaflavins have a significant anticancer effect. In this Perspective, we first state the physical and chemical properties, separation and purification methods, and biological formation pathways of theaflavins and analyze their safety and oral bioavailability and the structure-activity relationship of their antioxidant and anticancer activities; then, we describe in detail their anticancer effect in vitro and in vivo and highlight their various molecular targets involved in cancer inhibition. The anticancer molecular targets of theaflavins are mainly cell-cycle regulatory proteins, apoptosis-related proteins, cell-migration-related proteins, and growth transcription factors. Finally, the possibility of developing new health-care food based on theaflavins is discussed. This Perspective is expected to provide a theoretical basis for the anticancer application of theaflavins in the future.

F. Najafi, Guorui Wang, S. Mukherjee et al.

Abstract Previous experiments on the mechanics of graphene-based polymer nanocomposites report their mechanical properties far below theoretical predictions. A critical factor in this regard is the nature and strength of nanofiller/matrix interfacial bonding. Herein, beneficial effects of chemical functionalization on the interfacial mechanical properties of graphene-based polymer nanocomposites are investigated using complementary experiments and molecular dynamics (MD) simulations. We report that by tuning the extent and chemistry of the functionalized species, (approximately 10%), graphene-PMMA nanocomposites can achieve superior mechanical properties by improving the interfacial load transfer. Compared to pure PMMA, an increase of 46% in Young's modulus and 119% in energy absorbed per unit volume during fracture, respectively, were achieved for 10% functionalized nanocomposites. Such an increase in energy absorbed was caused by a transition in crack propagation mechanism from interfacial slippage to crack arresting behavior, owing to the enhanced interfacial bonding. MD simulations revealed that such a change in mechanism is caused by the formation of both hydrogen bond networks and physical entanglements at the interface. While the methodology can be applied for different nanocomposite systems, the present results may provide an avenue for more efficient design of graphene-based nanocomposite structures.

Guogang Xue, Jianjun Tian, Jun Bao et al.

Polymerizable ionic liquid (PIL) of hydrolyzed vinyl imidazolium nitrate ([HVim]NO3) was used to prepare the non-precious metal catalyst (NPMC) of Fe-N/C. The material was characterized for catalytic performance toward oxygen reduction reaction (ORR). The onset and half wave potential for ORR is 0.90 and 0.64 VRHE, respectively. The electrochemical tests show that the Fe-N/C material is a potential NPMC for ORR. Therefore, the PIL is a promising precursor for ORR catalyst free of noble metal.

Bouramtane, Soukaina, Bretin, Ludovic, Godard, Jérémy et al.

Most photosensitizers (PS) suffer from a lack of water solubility and from a low selectivity toward tumor cells. Delivery systems using nanoparticles make it possible to improve PS water solubility, and also tumor targeting via the enhanced permeability and retention (EPR) effect. Among the organelles, mitochondria are attractive target sites for drug-delivery strategies since they perform a variety of key cellular processes. Our study was aimed at synthesizing nanoparticles consisting of xylan-carrying porphyrins attached to a triphenylphosphonium moiety, in order to enhance the PDT effect through mitochondrial targeting. Hybrid nanoparticles were designed that consisted of a silica core coated with xylan substituted with porphyrin derivatives carrying a triphenylphosphonium moiety. These hybrid nanoparticles have been constructed, along with their counterparts devoid of silica core, taking into consideration the controversy surrounding the use of silica nanoparticles. Phototoxicity experiments, conducted against the HCT-116 and HT-29 colorectal cancer cell lines, showed that nanoparticles with porphyrins bearing a triphenylphosphonium moiety exhibited an enhanced photocytotoxic effect in comparison with free porphyrin or nanoparticles with porphyrins without the triphenylphosphonium moiety.

A.A. Kachina

Shouguang Yao, Qiankun Jin, Zeyi Sun et al.

To obtain the variation law of OH- ion concentration and its influencing factors in the porous electrode of a zinc-nickel single-flow battery during battery charging, the lattice Boltzmann method is used in this study to simulate the transient mass transfer and electrochemical reaction via the (voxel)REV scale. The output is compared with pore scale. Results prove that the REV and the pore scale are consistent in the concentration distribution of the entire OH- field.The general law of the electrochemical reaction mechanism inside the porous electrode can be obtained by increasing current density,thus reducing charging time. However, the effect of reducing the charging time gradually decreases as the current density increases, and excessive current density causes considerable concentration polarization.When the electrode thickness is too large, the diffusion resistance of OH--ions increases. When the thickness of the electrode is too large,and the porosity of the porous electrode is too small, the diffusion resistance of OH--ions increases. This occurrence is not conducive to the diffusion of OH--ions. Both cause large concentration polarization in the electrode.

Wenping Zhao, Yemin Guo, Qingxue Zhao et al.

A novel impedance immunosensor was developed based on antibodies fixed on interdigitated array microelectrodes (IDAMs) to detect chlorpyrifos residues. Before use, IDAMs were cleaned using the best method among three methods. Anti-chlorpyrifos monoclonal antibodies were oriented on IDAM surfaces by staphylococcal protein A (SPA). SPA was immobilized on the microelectrode surfaces to provide a better interface for biocompatibility and to increase a fixed amount of antibodies. The immobilized antibodies captured target chlorpyrifos and changed the impedance of the IDAM surface. Electrochemical impedance spectroscopy (EIS) was then used to characterize the change. According to the test results, the best volumes and concentrations of SPA, anti-chlorpyrifos antibodies and BSA drops on IDAMs, as well as the volume and pH of the working buffer used in the experiments were determined. Under the optimal conditions, the correlation between impedance signals and the chlorpyrifos concentration of the incubated electrochemical biosensor was studied. To deal with measured data using normalized impedance and analyze the correlation of two concentrations (1 μg/mL and 10 μg/mL) of chlorpyrifos with impedance signals at seven specific frequencies (1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz and 1 MHz), the optimal frequency (100 Hz) was selected. The standard curve was drawn after extracting the impedance values under different concentrations of pesticides at the frequency of 100 Hz. To determine the normalized impedance change (NIC) at 100 Hz against the logarithm from 1 ng/mL to 100 μg/mL of the chlorpyrifos concentration (LgC), the used regression equation was y = 132.62x + 733.1, with a linear correlation coefficient of 0.9946. The lowest limit of detection (LOD) for this biosensor was 1 ng/mL. The immunosensor showed good specificity and sensitivity for chlorpyrifos detection.