Hydroxyl Research Articles

Preparation of nano-silver containing black phosphorus based on quaternized chitosan hydrogel and evaluating its effect on skin wound healing

Hydrogels with favorable biocompatibility and antibacterial properties are essential in postoperative wound hemorrhage care, facilitating rapid wound healing. The present investigation employed electrostatic adsorption of black phosphorus nanosheets (BPNPs) and nano‑silver (AgNPs) to cross-link the protonated amino group NH3+ of quaternized chitosan (QCS) with the hydroxyl group of hyaluronic acid (HA). The electrostatic interaction between the two groups resulted in the formation of a three-dimensional gel network structure. Additionally, the hydrogel containing AgNPs deposited onto BPNPs was assessed for its antibacterial properties and effects on wound healing. Hydrogel demonstrated an outstanding drug-loading capacity and could be employed for wound closure. AgNPs loaded on the BPNPs released silver ions and exhibited potent antibacterial properties when exposed to 808 nm near-infrared (NIR) radiation. The ability of the hydrogel to promote wound healing in an acute wound model was further evaluated. The BPNPs were combined with HA and QCS in the aforementioned hydrogel system to improve adhesion, combine the photothermal and antibacterial properties of the BPNPs, and promote wound healing. Therefore, the reported hydrogels displayed excellent biocompatibility and hold significant potential for application in the field of tissue engineering for skin wound treatment.

CHEMICAL MODIFICATION OF ROAD PETROLEUM BITUMEN WITH MALEIC ANHYDRIDE AND POLYETHYLENE GLYCOLS

A number of problems arise in the production and application of road bitumen. One of them is unsatisfactory operational characteristics, mainly heat resistance, elasticity and adhesion between the binder and aggregate. With an increase in the intensity of traffic, an increase in the volume of heavy goods transportation, the mass of cars, together with the influence of weather and climate factors on the structure, this leads to the destruction of the road surface. The work describes the results of the study of the process of chemical modification of road petroleum bitumen with maleic anhydride and polyethylene glycols (PEG) to obtain bitumen-polymer mixtures, which, in addition to good heat resistance, also have high elasticity. When modifying road bitumen with maleic anhydride, the latter acts as a certain narrowing link, which contains on the one hand a double bond that interacts with bitumen, and on the other hand an anhydride group that can interact with various polymers containing functional groups (hydroxyl, epoxy and other). Further, by adding a polymer to maleinized bitumen (bitumen modified with maleic anhydride), the resulting bitumen-polymer mixtures can be given various properties (heat resistance, elasticity, adhesion, and others). Polyethylene glycol is a cheap polymer capable of interacting with the anhydride group of maleic anhydride in bitumen on the hydroxyl group. It was established that the effect of maleic anhydride and maleic anhydride together with PEG on the heat-resistant characteristics of bitumen is the same regardless of the modification conditions. Compared to the original bitumen, the obtained BPS is characterized by a higher softening temperature, lower penetration and ductility. The temperature of brittleness is not rapid, but it is increasing. The influence of the used modifiers on bitumen elasticity is significant and depends on the modification conditions. It was established that PEG 2000 is the optimal PEG for modifying maleinized bitumen, from the point of view of ensuring good bitumen elasticity.

Antioxidant properties of catechin and its 3′O-α-glucoside: Insights from computational chemistry calculations

Density functional theory (DFT) calculations were used to investigate the conformational landscape of catechin and one of its main glucoside derivative (catechin-3′ O- α −glucopyranoside), and to determine the corresponding antioxidant properties. These investigations were carried out in benzene and water using the SMD universal continuum solvation model. Both properties were found to be significantly affected. The structures are characterized in both solvents by strong intramolecular hydrogen bonds (IMHB). In an apolar environment, Hydrogen Atom Transfer (HAT) is by far favored whereas in water the Sequential Proton Loss Electron Transfer (SPLET) mechanism is strongly preferred. In benzene, the catechin fragment has the best antioxidant character (from 27 kJ/mole) whereas in polar surroundings, the glucoside derivative has a slightly better antiradical activity (from 5 kJ/mole). Our results confirm the key role of the 3′-OH and 4′-OH groups of the catechole ring in these properties.

The Resource Utilization of Poplar Leaves for CO2 Adsorption.

Every late autumn, fluttering poplar leaves scatter throughout the campus and city streets. In this work, poplar leaves were used as the raw material, while H3PO4 and KOH were used as activators and urea was used as the nitrogen source to prepare biomass based-activated carbons (ACs) to capture CO2. The pore structures, functional groups and morphology, and desorption performance of the prepared ACs were characterized; the CO2 adsorption, regeneration, and kinetics were also evaluated. The results showed that H3PO4 and urea obviously promoted the development of pore structures and pyrrole nitrogen (N-5), while KOH and urea were more conductive to the formation of hydroxyl (-OH) and ether (C-O) functional groups. At optimal operating conditions, the CO2 adsorption capacity of H3PO4- and KOH-activated poplar leaves after urea treatment reached 4.07 and 3.85 mmol/g, respectively, at room temperature; both showed stable regenerative behaviour after ten adsorption-desorption cycles.

Chemically functionalized AlN quantum dots for effective sensing and removal of methanol, ethanol, and formaldehyde: A first principle study

In this study, we delve into the structural and electronic intricacies of 2D aluminum nitride quantum dots (AlN-QDs) and their derivatives. Through detailed analysis, we uncover notable variations in bond lengths upon passivation with elements such as fluorine (F) and hydroxyl (OH) groups, with the latter exhibiting a particularly intriguing stability profile with a binding energy of 5.171 eV. Our investigation reveals a substantial energy gap of ∼5 eV in AlN-QDs, indicating enhanced electron confinement and optimal conditions for semiconductor applications. Furthermore, we elucidate the electron donation properties of nitrogen atoms and electron acceptance tendencies of aluminum atoms within AlN-QDs, shedding light on their unique electronic structure. Quantum stability assessments unveil charge distribution asymmetries and variations in electronegativity, contributing to a deeper understanding of AlN-QDs' robustness. We also demonstrate a significant enhancement in electrical conductivity, notably with AlN-QDs-surf-2CO exhibiting remarkable performance. Additionally, our study showcases AlN-QDs-OH's exceptional adsorption capabilities, evidenced by significantly higher adsorption energies for small organic compounds, highlighting their potential as highly effective sensors. Optical investigations further reinforce these findings, revealing distinct shifts in absorption spectra upon adsorption, which underscore the substantial impact of adsorbates on AlN-QDs' optical properties

Combination Mechanism of Soil Dissolved Organic Matter and Cu2+ in Vegetable Fields, Forests and Dry Farmland in Lujiang County

Dissolved organic matter (DOM) serves as a critical link in the migration and transformation of heavy metals at the soil–solid interface, influencing the migration behaviour and transformation processes of Cu2+ in soil. There have been studies on the combination mechanisms between DOM and Cu2+ in paddy soils. However, the adsorption/complexation and redox processes between DOM and Cu2+ in other agricultural soil types (such as dry farmland and vegetable fields) are unclear. In order to reveal the combination process of DOM with Cu in different agricultural soil types and the dynamic changes in chemical behaviour that occur, this study analysed the variability of DOM components and structure in three soils using three-dimensional fluorescence spectroscopy and X-ray photoelectron spectroscopy. In addition, the priority order of different DOM compounds in combination with Cu and the change process in relation to the Cu valence state in the soil of Lujiang County, Anhui Province, was revealed based on laboratory experiments. The results showed that the composition of soil DOM was mainly composed of humic-like and fulvic-like substances with a clear terrestrial origin and that the organic matter showed a high degree of decomposition characteristics. The results indicated that the composition of soil DOM is mainly composed of humic and fulvic acid-like substances, and they have obvious characteristics of terrestrial origin. In addition, the soil organic matter showed high decomposition characteristics. The complex stability constants (lgKM) of humic acid-like substances with Cu2+ follow the order of forest land (lgKM = 5.21), vegetable land (lgKM = 4.90), and dry farmland (lgKM = 4.88). The lgKM of fulvic acid-like substances with Cu2+ is in the order of dry farmland (lgKM = 4.51) and vegetable land (lgKM = 4.39). Humic acid-like substances in soil DOM combine preferentially with Cu2+, showing a stronger chelating affinity than fulvic acid-like substances. Cu2+ complexes mainly include hydroxyl, phenolic hydroxyl and amino functional groups are included in soil DOM, accompanied by redox reactions. In comparison to dry farmland, the soil DOM in forest and vegetable fields undergoes more intense redox reactions simultaneously with the chelation of Cu2+. Therefore, the application of organic fertilisers to vegetable and forest soils may lead to uncertainties concerning the fate of heavy metals with variable chemical valence. These results contribute to a deeper understanding of the interaction mechanisms between DOM and Cu2+ in agricultural soils.

Humic acid-based polyphenol-functionalized collagen fiber for efficient recognition capture of iodine vapor

Effective capture of radioactive iodine vapor is a crucial part of the spent fuel reprocessing process. In this study, humic acid (HA), which has excellent recognition capture of iodine vapor, is introduced as the active site construction center, functionalizing and modifying alkali-activated collagen fiber (ACF), to prepare the biomass composite functional materials (HA@ACF). The results demonstrate that HA@ACF exhibits exceptional recognition ability and a strong affinity for iodine vapor, with an adsorption capacity of 2811.8 mg/g (ACF is only 1068.6 mg/g). Simultaneously, under relative humidity of 27 % and strong acid conditions, the iodine vapor capture capacity of HA@ACF only decreased by 17.2 %, indicating that the material exhibits excellent iodine capture performance under complex conditions. The excellent adsorption performance is attributed to the synergistic effect of abundant −NHR, C = O, and phenolic hydroxyl active sites in HA@ACF, which recognize and induce iodine vapor, resulting in the capture of iodine molecules as I3-. Meanwhile, DFT calculations reveal the excellent adsorption energy (−0.51 eV) of iodine vapor on the phenolic hydroxyl groups on HA. Therefore, the HA@ACF biomass composite functional material can be an ideal candidate adsorbent for the efficient recognition capture of radioactive iodine vapor in airborne effluent.

Combining Siloxane-Based polybenzoxazine with Poly(ethylene-co-vinyl acetate/hydroxyl) for tougher, more Stable, and Self-Healable materials

Cross-linked EVOH containing dynamic silyl ether bonds with improved toughness and processability have been prepared by taking advantage of both ethylene vinyl alcohol (EVOH) and benzoxazine chemistry. For that, the cross-linked EVOH was synthesized through a trans etherification reaction between siloxane mono-functional benzoxazine and pendant hydroxyl groups on ethylene vinyl alcohol (EVOH) copolymer. The precursor EVOH copolymer was obtained by hydrolysis of the commercially available and inexpensive ethylene–vinyl acetate copolymer (EVA). The chemical structures of polymers were analyzed by proton nuclear magnetic resonance (1H NMR) spectra and Fourier transform infrared (FTIR) spectroscopy. The curing and thermal stability were researched by using differential scanning calorimetry (DSC) and a thermogravimetric analyzer (TGA), respectively. The mechanical properties via the stress–strain analysis were examined to identify the effect of the benzoxazines with the silyl ether group on the toughness and self-healing ability of the modified EVOH.

Effects of cellulose diameter on the formation and rheological properties of edible walnut oleogels structured by cellulose nanofiber

Oleogel of edible vegetable oils structured by cellulose nanofiber (CNF) via emulsion-templated method has attracted many interests due to its potential substitute of saturated or trans-fats in food industry. The gelation mechanism of liquid oil is dominated by different intermolecular non-covalent interactions, while the type and strength of these interactions are greatly influenced by the structure and properties of the gelator factors. Here, the effect of different CNF diameter ranges (5–10 nm, 10–20 nm and 20–60 nm) was investigated for CNF-based walnut oil oleogels, under the same fiber length and surface carboxyl content of CNFs. The results showed that CNFs with diameters of <20 nm exhibited better emulsification properties, and effectively restrained droplet size increasing and aggregation, compared to CNF with diameter of 20–60 nm. The resultant oleogels with smaller CNF diameter exhibited higher oil-binding capacity (OBC, ∼85%) and better thermal stability of the resultant oleogels. More compact structure and stronger mechanical strength of oleogels were achieved with CNF diameters of <20 nm, which was verified by stronger textural hardness of the oleogels (0.46 N), as well as higher storage modulus (up to 1.1 × 105 Pa) and apparent viscosity in rheological measurement. The enhanced OBC and structure strength of oleogels with smaller CNF diameter could be attributed to the enhanced hydrogen bonding interactions between CNF molecules and CNFs with oil molecules during oleogelation, as the rigorously fibrillation exposed more surface hydroxyl groups as accessible hydrogen bonding sites during CNF preparation. This study improved the understanding about gelling properties of CNFs with different fiber diameters and provided an empirical basis for the construction of CNF-based oleogels with tunable hydrogen bonding interactions.

Synthesis and crystal structure of (NH4)[Ni3(HAsO4)(AsO4)(OH)2

The title compound, ammonium trinickel(II) hydrogen arsenate arsenate di-hydroxide, was synthesized under hydro-thermal conditions. Its crystal structure is isotypic with that of K[Cu3(HAsO4)(AsO4)(OH)2] and is characterized by pseudo-hexa-gonal (001) 2 ∞[Ni3As2O18/3(OH)6/3O1/1(OH)1/1]- layers formed from vertex- and edge-sharing [NiO4(OH)2] octa-hedra and [AsO3.5(OH)0.5] tetra-hedra as the building units. The hydrogen atom of the OH group shows occupational disorder and was refined with a site occupation factor of 1/2, indicating the equal presence of [HAsO4]2- and [AsO4]3- groups. Strong asymmetric hydrogen bonds between symmetry-related (O,OH) groups of the arsenate units [O⋯O = 2.588 (18) Å] as well as hydrogen bonds accepted by these (O,OH) groups from OH groups bonded to the NiII atoms [O⋯O = 2.848 (12) Å] link adjacent layers. Additional consolidation of the packing is achieved through N-H⋯O hydrogen bonds from the ammonium ion, which is sandwiched between adjacent layers [N⋯O = 2.930 (7) Å] although the H atoms could not be located in the present study. The presence of the pseudo-hexa-gonal 2 ∞[Ni3As2O18/3(OH)6/3O1/1(OH)1/1]- layers may be the reason for the systematic threefold twinning of (NH4)[Ni3(HAsO4)(AsO4)(OH)2] crystals. Significant overlaps of the reflections of the respective twin domains complicated the structure solution and refinement.

One-Step Synthesis of Alkali Metal-Hydroxyl Double Modified Graphite Phase Carbon Nitride and Photocatalytic Degradation of Phenolic Compounds

In this work, potassium ion-hydroxyl double modified graphite phase carbon nitride (KCN–OH) was synthesized in one step by alkali hydrothermal (AH) method. The as-prepared catalysts were characterized by XRD, FT-IR, UV–Vis, N2 adsorption, SEM, XPS, PL, ESR, TPD and EIS. The introduction of potassium ion causes the reduced crystal size, increased specific surface area and promoted electron–hole separation efficiency of as-prepared catalyst. The hydroxyl group not only further improves the electron–hole separation efficiency but, as the electron donor group, can also make stronger interaction between catalyst and acidic phenolic compounds. The photocatalytic degradation of phenol was investigated under visible light. The results show that the phenol degradation rate constant of KCN–OH is 0.22 h[Formula: see text] under visible light, which is over 3.7 and 2.0 times higher than that of neat g-C3N4 and single hydroxyl-modified g-C3N4. KCN–OH also displays outstanding catalytic and structural stability. The possible reaction mechanism is discussed in this paper.

Technological quality improvement of gluten‐free eggless cakes by the incorporation of untreated and modified hydrocolloids

SummaryThe study examined the impact of untreated β‐glucan (UtβG) and ozonated β‐glucan (OzβG) on the characteristics of batter and gluten‐free eggless cake prepared using finger millet and flaxseed flour by encompassing a comprehensive analysis of physical, rheological, textural, morphological, sensory and nutritional properties. As the β‐glucan level increased, batter density and viscosity demonstrated an upward trend. The frequency sweep test revealed that β‐glucan altered the rheological parameters of batter, with the storage modulus (G′) surpassing the loss modulus (G″), indicating more elastic properties. The inclusion of OzβG resulted in improved physical characteristics and decreased the cake hardness, attributed to the formation of carboxyl and hydroxyl groups. Cakes incorporated with 1.5% OzβG had the highest overall acceptability score. Hence, this study sheds light on the utilisation of untreated and modified oat β‐glucan in the development of gluten‐free eggless cake, potentially aiding the bakery industry in meeting the rising demands for such products.

Isolation and characterization of Stenotrophomonas pavanii GXUN74707 with efficient flocculation performance and application in wastewater treatment.

The identification of microorganisms with excellent flocculants-producing capability and optimization of the fermentation process are necessary for the wide-scale application of bioflocculants. Therefore, we isolated and identified a highly efficient flocculation performance strain of Stenotrophomonas pavanii GXUN74707 from the sludge. The optimal fermentation and flocculation conditions of strain S. pavanii GXUN74707 was in fermentation medium with glucose and urea as the carbon and nitrogen sources, respectively, at pH 7.0 for 36 h, which treatment of kaolin suspension with 0.5 mL of the fermentation broth resulted in a flocculation rate of 99.0%. The bioflocculant synthesized by strain S. pavanii GXUN74707 was found mainly in the supernatant of the fermentation broth. Chemical analysis revealed that the pure bioflocculant consisted of 79.70% carbohydrates and 14.38% proteins. The monosaccharide components of MBF-GXUN74707 are mainly mannose (5.96 μg/mg), galactose (1.86 μg/mg), and glucose (1.73 μg/mg). Infrared spectrometric analysis showed the presence of carboxyl (COO-), hydroxyl (-OH) groups. The SEM images showed clumps of rod-shaped bacteria with adhesion of extracellular products. Furthermore, the strain decolored dye wastewater containing direct black, direct blue, and Congo red by 89.2%, 95.1%, 94.1%, respectively. The chemical oxygen demand (COD) and biological oxygen demand (BOD) removal rates after treatment of aquaculture wastewater with the fermentation broth were 68% and 23%, respectively. This study is the first to report the performance and application of strain Stenotrophomonas pavanii in wastewater flocculation. The results indicate that strain S. pavanii is a good candidate for the production novel bioflocculants and demonstrates its potential industrial practicality in biotechnology processes.

Mechanisms of carbon dioxide extracting oil at the boundary layer on shale nanopore surface: insights from molecular dynamics

Boundary layer formed by crude oil on the shale nanopores surface hinders fluidity of crude oil and leads to a decline in oil recovery. CO2 injection has been considered as an effective method to enhance shale oil recovery. However, the impact of CO2 on the disruption of boundary layers within shale nanopores and the extraction mechanisms of crude oil during the recovery process remains unclear. In this work, molecular dynamics simulation was employed to investigate the process of using scCO2 to extract crude oil from shale nanopore surface. During the process of scCO2 extraction, polar molecules have the capability to reduce the diffusion coefficient, prolong the residence time, and decrease flowability of decane, ultimately resulting in a deterioration of its kinetic properties. Phenol, with its hydrophilic hydroxyl group, closely adheres to the shale surface, while the oleophylic benzene ring covers the shale surface, causing a transition in the wettability of this segment from hydrophilic to oleophylic. As a result, a substantial adsorption of decane occurs on phenol. The research findings contribute to the comprehension of the scCO2 extraction mechanism and the advancement of unconventional oil and gas resources.

Unique Binding Sites of Uricosuric Agent Dotinurad for Selective Inhibition of Renal Uric Acid Reabsorptive Transporter URAT1.

Dotinurad was developed as a uricosuric agent, inhibiting urate (UA) reabsorption through the UA transporter URAT1 in the kidneys. Due to its high selectivity for URAT1 among renal UA transporters, we investigated the mechanism underlying this selectivity by identifying dotinurad binding sites specific to URAT1. Dotinurad was docked to URAT1 using AutoDock4, utilizing the AlphaFold2-predicted structure. The inhibitory effects of dotinurad on wild-type and mutated URAT1 at the predicted binding sites were assessed through URAT1-mediated [14C]UA uptake in Xenopus oocytes. Nine amino acid residues in URAT1 were identified as dotinurad-binding sites. Sequence alignment with UA-transporting organic anion transporters (OATs) revealed that H142 and R487 were unique to URAT1 among renal UA-transporting OATs. For H142, IC50 values of dotinurad increased to 62, 55, and 76 nM for mutated URAT1 (H142A, H142E, and H142R, respectively), compared to 19 nM for the wild-type, indicating that H142 contributes to URAT1-selective interaction with dotinurad. H142 was predicted to interact with the phenyl-hydroxyl group of dotinurad. The IC50 of the hydroxyl group methylated dotinurad (F13141) was 165 μM, 8,420-fold higher than dotinurad, suggesting the interaction of H142 and the phenyl-hydroxyl group by forming a hydrogen bond. Regarding R487, URAT1-R487A exhibited a loss of activity. Interestingly, the URAT1-H142A/R487A double mutant restored UA transport activity, with the IC50 value of dotinurad for the mutant (388 nM) significantly higher than that for H142A (73.5 nM). These results demonstrate that H142 and R487 of URAT1 determine its selectivity for dotinurad, a uniqueness observed only in URAT1 among UA-transporting OATs. Significance Statement Dotinurad selectively inhibits the urate reabsorption transporter URAT1 in renal urate-transporting OATs. This study demonstrates that dotinurad interacts with H142 and R487 of URAT1, located in the extracellular domain and unique among OATs when aligning amino acid sequences. Mutations in these residues reduce affinity of dotinurad for URAT1, confirming their role in conferring selective inhibition. Additionally, the interaction between dotinurad and URAT1 involving H142 was found to mediate hydrogen bonding.

Recognition of a Single β-D-Xylopyranose Molecule by Xylanase GH11 from Thermoanaerobacterium saccharolyticum

The endo-β-1,4-xylanase glycosyl hydrolase (GH11) decomposes the backbone of xylan into xylooligosaccharides or xylose. These enzymes are important for industrial applications in the production of biofuel, feed, food, and value-added materials. β-D-xylopyranose (XYP, also known as β-D-xylose) is the fundamental unit of the substrate xylan, and understanding its recognition is fundamental for the initial steps of GH11’s molecular mechanism. However, little is known about the recognition of a single XYP molecule by GH11. In this study, the crystal structures of GH11 from Thermoanaerobacterium saccharolyticum (TsaGH11) complexed with an XYP molecule were determined at a resolution of 1.7–1.9 Å. The XYP molecule binds to subsite −2 of the substrate-binding cleft. The XYP molecule is mainly stabilized by a π–π interaction with the conserved Trp36 residue. The O2 and O3 atoms of XYP are stabilized by hydrogen bond interactions with the hydroxyl groups of Tyr96 and Tyr192. The conformation of the thumb domain of TsaGH11 does not play a critical role in XYP binding, and XYP binding induces a shift in the thumb domain of TsaGH11 toward the XYP molecule. A structural comparison of TsaGH11 with other GH11 xylanases revealed that the XYP molecule forms π–π stacking with the center between the phenyl and indoline ring of Trp36, whereas the XYP molecule unit from xylobiose or xylotetraose forms π–π stacking with the indoline of Trp36, which indicates that the binding modes of the substrate and XYP differ. These structural results provide a greater understanding of the recognition of XYP by the GH11 family.

Discovery of potential anti- Staphylococcus aureus natural products and their mechanistic studies using machine learning and molecular dynamic simulations

The structure-activity analysis (SAR) and machine learning were used to investigate potential anti-S. aureus agents in a faster method. In this study, 24 oxygenated benzene ring components with S. aureus inhibition capacity were confirmed by literature exploring and in-house experiments, and the SAR analysis suggested that the hydroxyl group position may affect the anti-S. aureus activity. The 2D-MLR-QSAR model with 9 descriptors was further evaluated as the best model among the 21 models. After that, hesperetic acid and 2-HTPA were further explored and evaluated as the potential anti-S. aureus agents screening in the natural product clustering library through the best QSAR model calculation. The antibacterial capacities of hesperetic acid and 2-HTPA had been investigated and proved the similar predictive pMIC value resulting from the QSAR model. Besides, the two novel components were able to inhibit the growth of S. aureus by disrupting the cell membrane through the molecular dynamics simulation (MD), which further evidenced by scanning electron microscopy (SEM) test and PI dye results. Overall, these results are highly suggested that QSAR can be used to predict the antibacterial agents targeting S. aureus, which provides a new paradigm to research the molecular structure-antibacterial capacity relationship.

Preparation of a Novel Oat β-Glucan-Chromium(III) Complex and Its Hypoglycemic Effect and Mechanism.

This study synthesized a novel oat β-glucan (OBG)-Cr(III) complex (OBG-Cr(III)) and explored its structure, inhibitory effects on α-amylase and α-glucosidase, and hypoglycemic activities and mechanism in vitro using an insulin-resistant HepG2 (IR-HepG2) cell model. The Cr(III) content in the complex was found to be 10.87%. The molecular weight of OBG-Cr(III) was determined to be 7.736 × 104 Da with chromium ions binding to the hydroxyl groups of OBG. This binding resulted in the increased asymmetry and altered spatial conformation of the complex along with significant changes in morphology and crystallinity. Our findings demonstrated that OBG-Cr(III) exhibited inhibitory effects on α-amylase and α-glucosidase. Furthermore, OBG-Cr(III) enhanced the insulin sensitivity of IR-HepG2 cells, promoting glucose uptake and metabolism more efficiently than OBG alone. The underlying mechanism of its hypoglycemic effect involved the modulation of the c-Cbl/PI3K/AKT/GLUT4 signaling pathway, as revealed by Western blot analysis. This research not only broadened the applications of OBG but also positioned OBG-Cr(III) as a promising Cr(III) supplement with enhanced hypoglycemic benefits.

An Efficient, Amine-Specific, and Cost-Effective Method for TMT 6/11-plex Labeling Improves the Proteome Coverage, Quantitative Accuracy and Precision.

Tandem mass tags (TMT) are widely used in proteomics to simultaneously quantify multiple samples in a single experiment. The tags can be easily added to the primary amines of peptides/proteins through chemical reactions. In addition to amines, TMT reagents also partially react with the hydroxyl groups of serine, threonine, and tyrosine residues under alkaline conditions, which significantly compromises the analytical sensitivity and precision. Under alkaline conditions, reducing the TMT molar excess can partially mitigate overlabeling of histidine-free peptides, but has a limited effect on peptides containing histidine and hydroxyl groups. Here, we present a method under acidic conditions to suppress overlabeling while efficiently labeling amines, using only one-fifth of the TMT amount recommended by the manufacturer. In a deep-scale analysis of a yeast/human two-proteome sample, we systematically evaluated our method against the manufacturer's method and a previously reported TMT-reduced method. Our method reduced overlabeled peptides by 9-fold and 6-fold, respectively, resulting in the substantial enhancement in peptide/protein identification rates. More importantly, the quantitative accuracy and precision were improved as overlabeling was reduced, endowing our method with greater statistical power to detect 42% and 12% more statistically significant yeast proteins compared to the standard and TMT-reduced methods, respectively. Mass spectrometric data have been deposited in the ProteomeXchange Consortium via the iProX partner repository with the data set identifier PXD047052.

Conformation Analysis and Stereodynamics of Symmetrically ortho-Disubstituted Carvacrol Derivatives.

The design and synthesis of analogs of natural products can be a valuable source of medicinal preparations for the pharmaceutical industry. In the present study, the structural elucidation of eleven derivatives of 2,4-dihalogeno substituted synthetic analogues of the natural compound carvacrol was carried out by means of NMR experiments, and of another thirteen by DFT calculations. By selective NOE experiments and the irradiation of CH signals of the isopropyl group, individual conformers were assigned as syn and anti. By comparing GIAO/B3LYP/6-311++G(d,p)-calculated and experimentally measured vicinal 3JCH spin-spin constants, this assignment was confirmed. An unusual relationship is reported for proton-carbon vicinal couplings: 3JCH (180°) < 3JCH (0°). The conformational mobility of carvacrols was studied by 2D EXSY spectra. The application of homonuclear decoupling technique (HOBS) to these spectra simplifies the spectra, improves resolution without reducing the sensitivity, and allows a systematic examination of the rotational barrier of all compounds via their CH signals of the isopropyl group in a wider temperature interval. The rate constants of the isopropyl rotation between syn and anti conformers were determined and the corresponding energy barriers (14-17 kcal/mol) were calculated. DFT calculations of the energy barriers in carvacrol derivatives allowed the determination of the steric origin of the restricted isopropyl rotation. The barrier height depends on the size of the 2- and 4-position substituents, and is independent of the derivatization of the OH group.