Search Results (129)

Bupleurum scorzonerifolium Willd. is a perennial herbaceous plant of the genus Bupleurum in the Apiaceae family. Also known as red Bupleurum, it is mainly distributed in Northeast China, North China and other regions and is a commonly used medicinal plant. It is difficult for the wild plant resources of Bupleurum scorzonerifolium Willd. to meet the market demand. In artificial cultivation, there are problems such as a low yield per plant, low quality, weakened stress resistance and variety degradation. The contents of bioactive components and metabolites in traditional Chinese medicinal materials vary significantly across different growth years. The growth duration directly impacts their quality and clinical efficacy. Therefore, determining the optimal growth period is one of the crucial factors in ensuring the quality of traditional Chinese medicinal materials. In this study, Gas Chromatography–Mass Spectrometry (GC-MS) and High-performance liquid chromatography (HPLC) were comprehensively applied to analyze the metabolically differential substances in different parts of Bupleurum scorzonerifolium Willd. By comparing the compositions and content differences of chemical components in different growth years and different parts, the chemical components with significant differences were accurately screened out. In order to further explore the dynamic change characteristics and internal laws of metabolites, a metabolic network was constructed for a visual analysis and, finally, to see the optimal growth years of Bupleurum scorzonerifolium Willd. This result showed that with the accumulation of the growth cycle, the height, root width, fresh mass and saikosaponins content of Bupleurum scorzonerifolium Willd. increased year by year. Except for sodium and calcium elements in the main shoot, the other elements were significantly reduced. In addition, 59 primary metabolites were identified by GC-MS, with the accumulation of the growth cycle, the contents of organic acids, sugars, alcohols and amino acids gradually decreased, while the contents of alkyl, glycosides and other substances gradually increased. There were 53 positive correlations and 18 negative correlations in the triennial Bupleurum scorzonerifolium Willd. grid, all of which were positively correlated with saikosaponins. Therefore, the triennial Bupleurum scorzonerifolium Willd. was considered to be the suitable growth year. It not only provided a new idea and method for the quality evaluation of Bupleurum scorzonerifolium Willd., but also provided a scientific basis for the quality control of Chinese herbs. Full article

The functionalisation of lignin-derived phenolics (guaiacol, 4-propylguaiacol, eugenol, isoeugenol, phenol, m-cresol, catechol, syringol, syringaldehyde, and vanillin) for the synthesis of thermoplastic polyurethanes (PUs) and polyester (PE) resins is herein described. Diols were synthesised from phenolics in a one-step reaction using either glycerol carbonate or ethylene carbonate as a greener, solvent-free synthetic route. Nine of the diols were selected for the synthesis of Pus, and two of the diols were used for the synthesis of PE resins, with their physical and thermal properties characterised. Analysis of the PUs by differential scanning calorimetry (DSC) confirmed their amorphous nature, while thermogravimetric analysis (TGA) suggested improved thermal stability for all PUs with the addition of an alkyl or aldehyde substituent on the benzene ring regardless of the diisocyanate used. However, lower PU thermal stabilities were observed with the use of an aliphatic diisocyanate over an aromatic diisocyanate in the absence of an additional substituent. Analysis of the PEs by DSC also confirmed that the clear resins were all amorphous, and gel permeation chromatography (GPC) revealed significantly higher molecular weights and dispersities when an aliphatic diacid was utilised over an aromatic diacid. Full article

The development of photoactive molecules for photothermal energy storage is a focus of research in solar energy utilization technology. Azobenzene photoswitch has emerged as a promising candidate for solar energy conversion and storage due to its unique photoisomerization characteristics. Nonetheless, a majority of azobenzene-based molecular photothermal systems have a significant drawback: they depend on ultraviolet light for E-to-Z isomerization to store photon energy rather than visible light, which seriously hinders the development of azobenzene photoswitch in practical solar energy utilization applications. In this study, an azobenzene photothermal molecule that can effectively store visible-light photon energy was design and synthesized, which includes a tetra-ortho-chlorinated azo structure as the “head” part and an alkyl chain at para-position as the “tail” part. The ultraviolet–visible and ¹H NMR spectrum indicated that the obtained tetra-ortho-chlorinated azobenzene photothermal molecule could effectively absorb and store photon energy under 550 nm irradiation and release the stored energy upon 430 nm light irradiation. The storage energy density of the charged azobenzene photothermal molecule was determined to be 13.50 kJ/mol through differential scanning calorimetry and 28.21 kJ/mol via density functional theory theoretical calculations. This discrepancy was ascribed to the 64% Z-isomer yield harvesting during the charging process. Furthermore, the obtained tetra-ortho-chlorinated azobenzene exhibited long-term energy storage (approximately 11 days of half-life) and cyclic stability (100 cycles). Notably, the E-isomer of tetra-ortho-chlorinated azobenzene exhibited a high degree of supercooling, which may be advantageous for use in extremely low-temperature environments. Full article

Here, we present two series of new electroactive compounds containing electron donors (carbazolyl) and electron acceptor (pyridinyl) fragments as potential host materials. The objective compounds 9-(2-ethylhexyl)-3,6-di [3-(methoxypyridin-3-yl)carbazol-9-yl]carbazoles RB71 and RB74 were synthesized by an Ullmann coupling reaction between the intermediate derivatives: 9-(2-ethylhexyl)-3,6-diiodocarbazole and corresponding 3-(methoxypyridin-3-yl)-9H-carbazole. Other target derivatives, 9-alkyl-3-[N-(9-alkylcarbazol-3-yl)-N-(4-methylpyridin-2-yl)amino]carbazoles RB70 and RB75, were also prepared, according to the Ullmann reaction method, from 2-amino-4-methylpyridine and the corresponding 3-iodo-9-alkylcarbazole. Thermogravimetric analysis confirmed that the new derivatives are highly thermally stable compounds, with 5% weight loss in the temperature range of 349 °C to 488 °C. According to differential scanning calorimetry results, some amorphous materials exhibit very high glass transition temperatures exceeding 150 °C in some cases, which is a significant advantage for compounds with potential applications in organic light-emitting devices. The electroluminescent properties of devices utilizing the new hosts RB71 or RB70 with 5.0, 10.0, 15.0, and 20.0 wt.% concentrations of the dopant tris(2-phenylpyridine)iridium(III), Ir(ppy)₃, were demonstrated. All the PhOLEDs emitted light at approximately 515 nm with CIE coordinates of (0.30, 0.61) due to Ir(ppy)₃ emissions. The most efficient device with RB71 host demonstrated a maximum power efficacy of 8.0 lm/W, maximum current efficiency of 12.7 cd/A, and maximal external quantum efficiency of 5.4% with a relatively low turn-on voltage of 4.3 eV, as well as luminance exceeding 4000 cd/m². Additionally, 15 wt.% Ir(ppy)₃ emitter-based PhOLED with RB70 host outperformed the other devices by displaying a maximum power efficacy of 9.6 lm/W, maximum current efficiency of 16.0 cd/A, and maximal external quantum efficiency of 6.7% with a relatively low turn-on voltage of 3.7 eV, as well as luminance reaching 11,200 cd/m². Some devices seem to exhibit higher efficiencies than those previously reported for OLEDs that utilize a 4,4′-bis(9-carbazolyl)-2,2′-biphenyl (CBP) host. Full article

Organic semiconductor materials are interesting due to their application in various organic electronics devices. [1]benzothieno[3,2-b][1]benzothiophene (BTBT) is a widely used building block for the creation of such materials. In this work, three novel solution-processable regioisomeric derivatives of BTBT—2,7-bis(3-octylthiophene-2-yl)BTBT (1), 2,7-bis(4-octylthiophene-2-yl)BTBT (2), and 2,7-bis(5-octylthiophene-2-yl)BTBT (3)—were synthesized and investigated. Their optoelectronic properties were characterized experimentally by ultraviolet–visible and fluorescence spectroscopy, time-resolved fluorimetry, and cyclic voltammetry and studied theoretically by Time-Dependent Density Functional Theory calculations. Their thermal properties were investigated by a thermogravimetric analysis, differential scanning calorimetry, polarizing optical microscopy, and in situ small-/wide-angle X-ray scattering measurements. It was shown that the introduction of alkyl substituents at different positions (3, 4, or 5) of thiophene moieties attached to a BTBT fragment significantly influences the optoelectronic properties, thermal stability, and phase behavior of the materials. Thin films of each compound were obtained by drop-casting, spin-coating and doctor blade techniques and used as active layers for organic field-effect transistors. All the OFETs exhibited p-channel characteristics under ambient conditions, while compound 3 showed the best electrical performance with a charge carrier mobility up to 1.1 cm²·V⁻¹s⁻¹ and current on/off ratio above 10⁷. Full article

Glioblastoma (GBM) is the most common and lethal intracranial tumor in adults. Despite advances in the understanding of the molecular events responsible for disease development and progression, survival rates and mortality statistics for GBM patients have been virtually unchanged for decades and chemotherapeutic drugs used to treat GBM are limited. Arsenic derivatives, known as highly effective anticancer agents for leukemia therapy, has been demonstrated to exhibit cytocidal effects toward GBM cells by inducing cell death, cell cycle arrest, inhibition of migration/invasion, and angiogenesis. Differentiation induction of glioma stem-like cells (GSCs) and inhibition of neurosphere formation have also been attributed to the cytotoxicity of arsenic derivatives. Intriguingly, similar cytotoxic effects against GBM cells and GSCs have also been observed in natural agents such as anthocyanidins, tetrandrine, and bufadienolides. In the current review, we highlight the available data on the molecular mechanisms underlying the multifaceted anticancer activity of arsenic compounds and natural agents against cancer cells, especially focusing on GBM cells and GCSs. We also outline possible strategies for developing anticancer therapy by combining natural agents and arsenic compounds, as well as temozolomide, an alkylating agent used to treat GBM, in terms of improvement of chemotherapy sensitivity and minimization of side effects. Full article

Phenothiazine-based photosensitizers bear the intrinsic potential to substitute various expensive organometallic dyes owing to the strong electron-donating nature of the former. If coupled with a strong acceptor unit and the length of N-alkyl chain is appropriately chosen, they can easily produce high efficiency levels in dye-sensitized solar cells. Here, three novel D-A dyes containing 1H-tetrazole-5-acrylic acid as an acceptor were synthesized by varying the N-alkyl chain length at its phenothiazine core and were exploited in dye-sensitized solar cells. Differential scanning calorimetry showed that the synthesized phenothiazine derivatives exhibited behavior characteristic of molecular glasses, with glass transition and melting temperatures in the range of 42–91 and 165–198 °C, respectively. Based on cyclic and differential pulse voltammetry measurements, it was evident that their lowest unoccupied molecular orbital (LUMO) (−3.01–−3.14 eV) and highest occupied molecular orbital (HOMO) (−5.28–−5.33 eV) values were fitted to the TiO₂ conduction band and the redox energy of I⁻/I₃⁻ in electrolyte, respectively. The experimental results were supported by density functional theory, which was also utilized for estimation of the adsorption energy of the dyes on the TiO₂ and its size. Finally, the compounds were tested in dye-sensitized solar cells, which were characterized based on current–voltage measurements. Additionally, for the compound giving the best photovoltaic response, the efficiency of the DSSCs was optimized by a photoanode modification involving the use of cosensitization and coadsorption approaches and the introduction of a blocking layer. Subsequently, two types of tandem dye-sensitized solar cells were constructed, which resulted in an increase in photovoltaic efficiency to 6.37%, as compared to DSSCs before modifications, with a power conversion value of 2.50%. Full article

In this study, we synthesized a series of 3-hydroxy-4-pyridinone (3,4-HPO) chelators with varying lipophilicity by modifying the length of their alkyl chains. To investigate their interaction with lipid membranes, we employed differential scanning calorimetry (DSC) and electron paramagnetic resonance (EPR) spectroscopy using dimyristoylphosphatidylcholine (DMPC) and palmitoyloleoylphosphatidylcholine (POPC) liposomes as membrane model systems. DSC experiments on DMPC liposomes revealed that hexyl-substituted chelators significantly altered the thermotropic phase behavior of the lipid bilayer, indicating their potential as membrane property modulators. EPR studies on DMPC and POPC liposomes provided detailed insights into the depth-dependent effects of chelators on membrane fluidity. Our findings highlight the crucial role of alkyl chain length in determining the interaction of 3,4-HPO chelators with lipid membranes and offer valuable insights for the design of lipid-interacting therapeutic agents based on this scaffold. Full article

The present study demonstrated an improvement in both 1-heptene conversion and mono-heptyltoluene selectivity. It simultaneously depicted the isomerization reactions of 1-heptene and toluene alkylation over Y zeolite catalysts having a Si/Al of 3.5 and a surface area of 817 m²/g. The physical properties of the fresh zeolite catalyst were characterized using XRD, FTIR, XRF, TPD, and N₂ adsorption–desorption spectroscopy. The experimental part was carried out in a 100 mL glass flask connected to a reflux condenser at different reaction temperatures ranging from 70 to 90 °C, toluene:1-heptene ratios of 3–8, and catalyst weights of 0.25–0.4 g. The highest conversion of ~96% was obtained at the highest toluene:1-heptene ratio (i.e., 8:1), 0.25 g of zeolite Y, at 180 min of reaction time and under a reaction temperature of 90 °C. However, the selectivity of 2-heptyltoluene reached its highest value of ~25% under these conditions. Likewise, the kinetic modeling developed in this study helped describe the proposed reaction mechanism by linking the experimental results with the predicted results. The kinetic parameters were determined by nonlinear regression analysis using the MATLAB^® package genetic algorithm. The ordinary differential equations were integrated with respect to time using the fourth-order Runge–Kutta method, and the resulting mole fractions were fitted against the experimental data. The mean relative error (MRE) values were calculated from the experimental and predicted results, which showed a reasonable agreement with the average MRE being ~11.7%. The calculated activation energies showed that the reaction rate follows the following order: coking (55.9–362.7 kJ/mol) > alkylation (73.1–332.1 kJ/mol) > isomerization (69.3–120.2 kJ/mol), indicating that isomerization reactions are the fastest compared to other reactions. A residual activity deactivation model was developed to measure the deactivation kinetic parameters, and the deactivation energy value obtained was about 48.2 kJ/mol. Full article

Glioblastoma (GBL) is one of the more malignant primary brain tumors; it is currently treated by a multimodality strategy including surgery, and radio- and chemotherapy, mainly consisting of temozolomide (TMZ)-based chemotherapy. Tumor relapse often occurs due to the establishment of TMZ resistance, with a patient median survival time of <2 years. The identification of natural molecules with strong anti-tumor activity led to the combination of these compounds with conventional chemotherapeutic agents, developing protocols for integrated anticancer therapies. Curcumin (CUR), resveratrol (RES), and its glucoside polydatin (PLD) are widely employed in the pharmaceutical and nutraceutical fields, and several studies have demonstrated that the combination of these natural products was more cytotoxic than the individual compounds alone against different cancers. Some of us recently demonstrated the synergistic efficacy of the sublingual administration of a new nutraceutical formulation of CUR+PLD in reducing tumor size and improving GBL patient survival. To provide some experimental evidence to reinforce these clinical results, we investigated if pretreatment with a combination of CUR+PLD can improve TMZ cytotoxicity on GBL cells by analyzing the effects on cell cycle, viability, morphology, expression of proteins related to cell proliferation, differentiation, apoptosis or autophagy, and the actin network. Cell viability was assessed using the MTT assay or a CytoSmart cell counter. CalcuSyn software was used to study the CUR+PLD synergism. The morphology was evaluated by optical and scanning electron microscopy, and protein expression was analyzed by Western blot. Flow cytometry was used for the cell cycle, autophagic flux, and apoptosis analyses. The results provide evidence that CUR and PLD, acting in synergy with each other, strongly improve the efficacy of alkylating anti-tumor agents such as TMZ on drug-resistant GBL cells through their ability to affect survival, differentiation, and tumor invasiveness. Full article

Albuminuria may precede decreases in the glomerular filtration rate (GFR) and both tests are insensitive predictors of early stages of kidney disease. Our aim was to characterise the urinary proteome in black African individuals with albuminuria and well-preserved GFR from South Africa. This case-controlled study compared the urinary proteomes of 52 normoalbuminuric (urine albumin: creatinine ratio (uACR) < 3 mg/mmol) and 56 albuminuric (uACR ≥ 3 mg/mmol) adults of black African ethnicity. Urine proteins were precipitated, reduced, alkylated, digested, and analysed using an Evosep One LC (Evosep Biosystems, Odense, Denmark) coupled to a Sciex 5600 Triple-TOF (Sciex, Framingham, MA, USA) in data-independent acquisition mode. The data were searched on Spectronaut^TM 15. Differentially abundant proteins (DAPs) were filtered to include those with a ≥2.25-fold change and a false discovery rate ≤ 1%. Receiver–operating characteristic curves were used to assess the discriminating abilities of proteins of interest. Pathway analysis was performed using Enrichr software. As expected, the albuminuric group had higher uACR (7.9 vs. 0.55 mg/mmol, p < 0.001). The median eGFR (mL/min/1.73 m²) showed no difference between the groups (111 vs. 114, p = 0.707). We identified 80 DAPs in the albuminuria group compared to the normoalbuminuria group, of which 59 proteins were increased while 21 proteins were decreased in abundance. We found 12 urinary proteins with an AUC > 0.8 and a p < 0.001 in the multivariate analysis. Furthermore, an 80-protein model was developed that showed a high AUC ˃ 0.907 and a predictive accuracy of 91.3% between the two groups. Pathway analysis found that the DAPs were involved in insulin growth factor (IGF) functions, innate immunity, platelet degranulation, and extracellular matrix organization. In albuminuric individuals with a well-preserved eGFR, pathways involved in preventing the release and uptake of IGF by insulin growth factor binding protein were significantly enriched. These proteins are indicative of a homeostatic imbalance in a variety of cellular processes underlying renal dysfunction and are implicated in chronic kidney disease. Full article

The presented studies aimed to evaluate the peripheral coordinating properties of a novel porphyrinoid family representative preceded by its synthesis for potential sensing purposes. Two synthetic pathways were employed to a obtain maleonitrile derivative, further used as a starting material in the cyclotetramerization reaction. In the first one, DAMN was used in sequential double-reductive alkylation with 2-thiophene-carboxyaldehyde and sodium borohydride. In the second, DAMN was used in a one-pot reaction with 2-thiophene-carboxyaldehyde in the presence of a 5-ethyl-2-methylpyridine borane complex in methanol and acetic acid. Following the Linstead approach, the cyclization reaction led to a novel symmetrical magnesium(II) octaaminoporphyrazine with methyl(2-thiophenylmethylene) substituents. The macrocycle’s electrochemical properties were assessed by cyclic and differential pulse voltammetries revealing one reduction and two oxidation peak potentials. The additional spectroelectrochemical measurements showed formation of a cationic form of the macrocycle at an applied potential of 0.6 V. The coordinating properties due to the palladium ion of novel porphyrazines were measured with the use of titration combined with UV–vis spectrometry. The titration of Pd²⁺ revealed the good sensing activity of porphyrazine in the range of 0.1 to 5 palladium molar equivalents. In addition, Pd²⁺ ions coordination was also assessed by electrochemical studies, indicating the peak potential shift of 0.1 V in the presence of metal cations. DFT calculations showed the good agreement between theoretical and experimental data in the UV–vis and ¹H NMR studies. Full article

With the continuous advancement of industrial technology, higher demands have been placed on the properties of gear oils, such as oxidation stability and shear resistance. Herein, the oxidation stability of high-viscosity metallocene poly-$\alpha$-olefins (mPAOs) was improved by chemical modification via aromatic amine alkylation. The modified mPAO base oils were synthesized separately with diphenylamine (mPAO-DPA) and N-phenyl-$\alpha$-naphthylamine (mPAO-NPA), and their applicability in industrial gear oil formulations was evaluated. The composition and physicochemical properties of the obtained samples were assessed using ¹H NMR spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, and the American Society for Testing and Materials standards (ASTM D445, ASTM D2270, ASTM D92, etc.) confirming the successful completion of the alkylation reaction. The oxidation stability of the samples was also evaluated using pressurized differential scanning calorimetry. The initial oxidation temperature of mPAO-NPA (230 °C) was 53 °C higher than that of mPAO, and the oxidation induction period of mPAO-DPA was nearly twice that of mPAO-NPA. Thermogravimetric analysis in air revealed the increased thermal decomposition temperature and improved thermal stability of modified mPAO. ISO VG 320 industrial gear oils were formulated using mPAO alkylated with N-phenyl-$\alpha$-naphthylamine(Lub-2) and commercially purchased PAO100 (Lub-1) as base oil components. The antioxidant performance of two industrial gear oils was evaluated through oven oxidation and rotating oxygen bomb tests. The oxidation induction period of Lub-2 was 30% higher than that of Lub-1, with the latter having a lower acid number and a smaller increase in viscosity at 40 °C. Finally, the friction performance of the samples was assessed on a four-ball friction tester, revealing the synergistic effect of the mPAO-NPA base oil with the HiTEC 3339 additive, forming a more stable oil film with a smaller wear scar diameter. Full article

Mass spectrometry has become the most prominent yet evolving technology in quantitative proteomics. Today, a number of label-free and label-based approaches are available for the relative and absolute quantification of proteins and peptides. However, the label-based methods rely solely on the employment of stable isotopes, which are expensive and often limited in availability. Here we propose a label-based quantification strategy, where the mass difference is identified by the differential alkylation of cysteines using iodoacetamide and acrylamide. The alkylation reactions were performed under identical experimental conditions; therefore, the method can be easily integrated into standard proteomic workflows. Using high-resolution mass spectrometry, the feasibility of this approach was assessed with a set of tryptic peptides of human serum albumin. Several critical questions, such as the efficiency of labeling and the effect of the differential alkylation on the peptide retention and fragmentation, were addressed. The concentration of the quality control samples calculated against the calibration curves were within the ±20% acceptance range. It was also demonstrated that heavy labeled peptides exhibit a similar extraction recovery and matrix effect to light ones. Consequently, the approach presented here may be a viable and cost-effective alternative of stable isotope labeling strategies for the quantification of cysteine-containing proteins. Full article

Dysregulated A>I(G) RNA editing, which is mainly catalyzed by ADAR1 and is a type of post-transcriptional modification, has been linked to cancer. A low response to therapy in breast cancer (BC) is a significant contributor to mortality. However, it remains unclear if there is an association between A>I(G) RNA-edited sites and sensitivity to genotoxic drugs. To address this issue, we employed a stringent bioinformatics approach to identify differentially RNA-edited sites (DESs) associated with low or high sensitivity (FDR 0.1, log2 fold change 2.5) according to the IC₅₀ of PARP inhibitors, anthracyclines, and alkylating agents using WGS/RNA-seq data in BC cell lines. We then validated these findings in patients with basal subtype BC. These DESs are mainly located in non-coding regions, but a lesser proportion in coding regions showed predicted deleterious consequences. Notably, some of these DESs are previously reported as oncogenic variants, and in genes related to DNA damage repair, drug metabolism, gene regulation, the cell cycle, and immune response. In patients with BC, we uncovered DESs predominantly in immune response genes, and a subset with a significant association (log-rank test p < 0.05) between RNA editing level in LSR, SMPDL3B, HTRA4, and LL22NC03-80A10.6 genes, and progression-free survival. Our findings provide a landscape of RNA-edited sites that may be involved in drug response mechanisms, highlighting the value of A>I(G) RNA editing in clinical outcomes for BC. Full article