Hasil untuk "Organic chemistry"

Jian Li, Yunlong Zhou, Guochao Zhao et al.

Alkali metals in fuel seriously affect the normal operation of generator sets. Using agricultural waste (AW) from a corn field as raw material, the dynamic change of alkali metal K migration and transformation and the effect of competition between chlorine and sulfur on the behavior of AW were studied systematically. The results showed that transformation between different forms of K, especially water-soluble K, occurred. At low temperatures, K remained in the ash in the form of inorganic salt, and high temperature precipitated K and formed insoluble alkali metal compounds. Via FactSage thermodynamic equilibrium calculations, it was confirmed that KCl reacted with SiO₂ to form a K₂O·nSiO₂ molten mixture in combustion. K initially existed in the form of KCl (s) and K₂SO₄ (s), high temperature promoted its transformation and decomposition, and it was eventually released as KCl (g). During combustion, Cl was more volatile than K, while S reduced the release of K and Cl through sulfation reaction to reduce the sediment viscosity.

Thomas Sorrell, Yujun Liu, Fenyong Liu

Nucleic acid-based gene-interfering molecules, such as antisense oligonucleotides, ribozymes, and small interfering RNA (siRNA), represent exciting gene-targeting agents for therapeutic applications. RNase P ribozymes derived from M1 RNA, the catalytic RNA subunit of RNase P in <i>Escherichia coli</i>, have shown great promise as a novel nucleic acid-based gene interference approach to modulate gene expression. When M1 RNA is covalently linked to a guide sequence (GS), it can be engineered into a sequence-specific endonuclease M1GS ribozyme, which can hydrolyze any mRNA that base-pairs with the guide sequence. M1GS activity enhancement has been achieved through an in vitro selection process that introduced mutations into M1 RNA. This selection process generated ribozyme variants with improved cleavage efficiency and substrate affinity. Hepatitis B virus (HBV) chronically infects more than 250 million people worldwide and is the leading cause of cirrhosis and liver cancer globally. Current FDA-approved drugs cannot completely eliminate HBV chronic infections. RNase P ribozymes have recently been demonstrated to effectively inhibit HBV gene expression and replication in human cells. This review summarizes the recent progress in using RNase P ribozymes to inhibit HBV infection and discusses prospects for developing engineered RNase P ribozymes for therapeutic applications against HBV infection and associated diseases.

Ting-Rong Hsu, Pei-Hao Chen, Wei-Sheng Lin

Epilepsy is one of the most common neurological disorders in both children and adults, characterized by significant clinical heterogeneity and dynamic natural course. The pathophysiological roles of astrocytes in epilepsy have been increasingly recognized. Fluid biomarkers derived from astrocytes are actively studied in epileptic disorders, although their use remains limited in clinical practice. This review aims to compile and analyze clinical and experimental findings concerning astrocytic biomarkers in epilepsy and related conditions, with a focus on glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B). Herein we examine their roles in assessing seizure burden and temporal dynamics, explore their potential in distinguishing epileptic from psychogenic non-epileptic seizures, and discuss their therapeutic, prognostic, and mechanistic implications in the context of epileptic disorders.

Rubin Gulaboski

Understanding energetics and electron behavior has been pivotal in elucidating numerous fundamental phenomena, including electricity, corrosion, respiration, energy generation in biological systems, intermolecular interactions within living organisms, organic synthesis, drug development, enzyme functions, and the design of biosensors, among others. As 2024 records the centennial anniversary of the completion of the first polarograph by Nobel laureate Jaroslav Heyrovský (awarded the Nobel Prize in Chemistry in 1959), it presents an opportune moment to pay tribute to several eminent electrochemists who have made significant contributions to the field of voltammetric techniques. Following our recent acknowledgment of the outstanding women who have made substantial contributions to voltammetry in a prior publication, this article aims to briefly highlight the major achievements of several distinguished male figures in the field (Jaroslav Heyrovský, Allen J. Bard, Christian Amatore, Richard Compton, Jean-Michel Savéant, Fraser Armstrong, Fritz Scholz, Joseph Wang, Milivoj Lovrić, Valentin Mirčeski, Alan M. Bond). Given that many of these remarkable personalities have contributed both as authors and referees for the Macedonian Journal of Chemistry and Chemical Engineering, this tribute serves as a fitting acknowledgment of their remarkable accomplishments on the occasion of the journal's 50th anniversary.

Xiao-Nan Du, Yu He, You-Wen Chen et al.

Despite advancements in analytical technologies, the complex nature of cosmetic matrices, coupled with the presence of diverse and trace unauthorized additives, hinders the application of these technologies in cosmetics analysis. This not only impedes effective regulation of cosmetics but also leads to the continual infiltration of illegal products into the market, posing serious health risks to consumers. The establishment of cosmetic regulations is often based on extensive scientific experiments, resulting in a certain degree of latency. Therefore, timely advancement in laboratory research is crucial to ensure the timely update and adaptability of regulations. A comprehensive understanding of the composition of cosmetic matrices and their pretreatment technologies is vital for enhancing the efficiency and accuracy of cosmetic detection. Drawing upon the China National Medical Products Administration’s 2021 Cosmetic Classification Rules and Classification Catalogue, we streamline the wide array of cosmetics into four principal categories based on the following compositions: emulsified, liquid, powdered, and wax-based cosmetics. In this review, the characteristics, compositional elements, and physicochemical properties inherent to each category, as well as an extensive overview of the evolution of pretreatment methods for different categories, will be explored. Our objective is to provide a clear and comprehensive guide, equipping researchers with profound insights into the core compositions and pretreatment methods of cosmetics, which will in turn advance cosmetic analysis and improve detection and regulatory approaches in the industry.

Mahaboobbatcha Aleem, Yilu Zhou, Swati Deswal et al.

This study explores the surface chemistry and electrical responses of ultra-high-sensitivity SnO₂ MEMS arrays to enable a novel sequential detection methodology for detecting nitrogen dioxide (NO₂) and ethanol (C₂H₅OH) as a route to achieve selective gas sensing in electronic nose (E-nose) applications. Utilizing tin oxide (SnO₂) thin films deposited via atomic layer deposition (ALD), the array achieves the lowest reported detection limits of 8 parts per billion (ppb) for NO₂. The research delves into the detection mechanisms of NO₂ and C₂H₅OH, both individually and in subsequent exposures, assessing the sensor’s dynamic response across various operating temperatures. It demonstrates rapid response and recovery times, with averages of 48 s and 277 s for NO₂ and 40 and 48 for C₂H₅OH. Understanding the role of individual gases on the SnO₂ surface chemistry is paramount in discerning subsequent gas exposure behavior. The oxidizing behavior of C₂H₅OH following NO₂ exposure is attributed to interactions between NO₂ and oxygen vacancies on the SnO₂ surface, which leads to the formation of nitrate or nitrite species. These species subsequently influence interactions with C₂H₅OH, inducing oxidizing properties, and need to be carefully considered. Principal component analysis (PCA) was used to further improve the sensor’s capability to precisely identify and quantify gas mixtures, improving its applicability for real-time monitoring in complex scenarios.

A. V. Alieva, A. A. Djalilov, F. A. Khaydarova et al.

BACKGROUND: Since the very first outbreak, scientists have been trying to determine the most critical pathogenetic mechanisms for the development of COVID-19 and related complications, analyze individual subpopulations of patients with chronic diseases and develop optimal tactics to combat not only the infection itself but also its acute and chronic complications.AIM: to assess the COVID-19 course among patients with Type 1 and Type 2 DM.MATERIALS AND METHODS: A retrospective cohort study of Tashkent inhabitants, who had COVID-19 from April to D ecember 2020, was performed. The data were obtained from the single electronic database of registered cases of COVID-19. All data were analyzed using a logistic regression in STATA 17.0 software. Further, the matched case-control study was performed for patients with type 2 DM and no DM based on age, gender, and BMI.RESULTS: Of the 5023 analyzed subjects, 72.63% had no diabetes mellitus (DM), 4.24% had type 1 DM, 15.19% had type 2 DM, and 7.94% was diagnosed with DM during the COVID-19 infection. DM, overweight, and obesity were associated with severe COVID-19; the most significant risk of a severe course was found in persons with type 2 DM. The risk of a lethal outcome and the need for prescription of glucocorticoids did not show a significant association with diabetes in Tashkent. The clinical features of COVID-19 were more common in patients with type 2 DM, especially for shortness of breath, chest pain, and arrhythmia. The persons receiving SU have complained of dyspnea significantly more often than matched patients without DM. Metformin and DPP4i were the groups of drugs that were not associated with significantly increased risk of hospitalization of patients because of COVID-19. The matched case-control study did not reveal statistically significant differences in the disease course severity, need for hospitalization and glucocorticoids, and death depending on the glucose-lowering therapy preceding the onset of COVID-19.CONCLUSION: Diabetes, age and overweight/obesity were associated with severe course of COVID-19 in Tashkent. There was no statistical difference in COVID-19 severity depending on initial glucose-lowering therapy.

Maged S. Al-Fakeh, Maha A. Alsikhan, Jawza Sh Alnawmasi

A new class of biologically active mineral complexes was synthesized by reacting the following metal salts: MnCl₂·4H₂O, CoCl₂·6H₂O, CuCl₂·2H₂O, CrCl₃·6H₂O, and PdCl₂ respectively with 2-amino-4,6-dimethyl pyrimidine (ADMPY) and Schiff’s base resulting from the condensation reaction between benzaldehyde with <i>p</i>-phenylenediamine and 2-hydroxy-1-naphthaldehyde as ligands have been synthesized and characterized on the basis of their CHN, thermal analysis, XRD, SEM and magnetic measurements along with their FT-IR and UV-vis spectra. The scanning electron microscope SEM measurements and the calculations on the powder XRD data indicate the nano-sized nature of the prepared complexes (average size 32–88 nm). The spectral data confirmed the coordinated ligand (HL) via a nitrogen atom of an azomethine group (-C=N-) and phenolic -OH group and NH₂-ADMPY ligand with the metal ions. An octahedral geometry for all complexes has been proposed based on magnetic and electronic spectral data except Pd(II) complex, which has a tetrahedral geometry. Molecular modeling was performed for Cu(II) complex using the density functional method DFT/B3LYP to study the structures and the frontier molecular orbitals (HOMO and LUMO). The antioxidant of the complexes was studied using the 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical-scavenging assays. The metal complexes were tested in vitro for anticancer activities against two cancer lines A-549 and MRC-5 cells. Cu(II) and Pd(II) complexes showed the highest cytotoxicity effect, comparable to that of other cis-platinum-based drugs. The complexes showed significant activity against fungi and bacteria.

Shasha Yin, Yu’e Guo, Xinyue Wen et al.

Background: The expression levels of the programmed cell death ligand 1 (PD-L1), known as an immune-inhibitory molecule, are closely associated with cancer stem cell (CSCs) immune escape. Recently, PD-L1 has also been reported to be able to regulate the self-renewal of cancer stem cells. However, The expression and intrinsic role of PD-L1 in endometrial cancer stem-like cell (ECSC) maintenance and its underlying mechanism of action remain unclear. Methods: Using flow cytometry and western blot assays, we have demonstrated that PD-L1 expression is higher in ECSCs derived from endometrial cancer than in nonstem-like cancer cells. Using mouse xenograft assays for ECSC tumorigenicity. Using gene reporter assay for uncovering the regulation mechanism of PD-L1 in the hypoxia. Results: We revealed the high expression levels of PD-L1 in ECSCs and its correlation with self-renewal. We further found that PD-L1 knockdown reduced expression of several pluripotency-related genes (aldehyde dehydrogenase 1 (ALDH1), CD133, OCT4, SOX2, NANOG), impaired ECSC proliferation and undifferentiated colonies and decreased the number of CD133 positive ECSCs and the number of stem-like spheres. Furthermore, we found that PD-L1 knockdown inhibited ECSC tumorigenicity and the PD-L1 induced self-renewal capability of ECSCs was dependent upon hypoxia HIF-1α and HIF-2α activation. Conclusions: These data link ECSC maintenance to PD-L1 expression through hypoxia and suggest a promising target for PD1/PD-L1 immunotherapy.

Li Tao, Xiaomeng Ren, Wenhui Zhai et al.

Non-canonical nuclear factor kappa B (NF-κB) signaling pathway regulates many physiological and pathological processes, including liver homeostasis and diseases. Recent studies demonstrate that non-canonical NF-κB signaling pathway plays an essential role in hyperglycemia, non-alcoholic fatty liver disease, alcoholic liver disease, liver regeneration, liver injury, autoimmune liver disease, viral hepatitis, and hepatocellular carcinoma. Small-molecule inhibitors targeting to non-canonical NF-κB signaling pathway have been developed and shown promising results in the treatment of liver injuries. Here, the recent advances and future prospects in understanding the roles of the non-canonical NF-κB signaling pathways in the regulation of liver diseases are discussed.

Peipei Yang, Mengya Lu, Jing Zhao et al.

By applying the hydrophilic ionic liquid, 1-butyl-3-methylimidazolium chloride ([C₄mim]Cl), and inorganic salts (K₃PO₄), an ionic liquid aqueous two-phase system (ILATPS) was established for the separation of <i>Dendrobium huoshanense</i> polysaccharides (DhPs) and proteins. The effects of inorganic salt concentration, IL quantity, crude DhPs concentration, pH value and temperature were studied to achieve the optimal condition. With the best combination of ILATPS (1.75 g K₃PO₄, 1.25 g [C₄mim]Cl, 10 mg crude DhPs and 5.0 mL ddH₂O at pH 7.0 under 25 °C), the extraction efficiency rates for DhPs and proteins were 93.4% and 90.2%, respectively. The processed DhPs retrieved from the lower salt-rich phase comprised mannose, glucose, galactose, arabinose, and galacturonic acid with a molar ratio of 185:71:1.5:1:1 and the molecular weight was 2.14 × 10⁵ Da. This approach is fast, simple and environmentally friendly. It provides a new insight into purifying functional polysaccharides of plant origin.

Nikita Frolov, Elena Detusheva, Nadezhda Fursova et al.

This work is devoted to the investigation of biocidal properties of quaternary ammonium compounds (QACs) based on pyridine structures with aromatic spacers, and their widely known analogs, against clinically significant microorganisms. This study is focused on investigating their antimicrobial activity (minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs)), antibiofilm properties (minimum biofilm inhibitory concentrations (MBICs) and minimum biofilm eradication concentrations (MBECs)), synergetic effect with different alcohols in antiseptic formulations, and bacterial resistance development. It was shown that all combined analogue preparations had a higher level of antibacterial activity against the tested bacterial strains, with a 16- to 32-fold reduction in MICs and MBCs compared to previously used antiseptic preparations. Moreover, hit-QACs demonstrated a stable effect against Gram-negative <i>E. coli</i>, <i>K. pneumoniae,</i> and <i>A. baumannii</i> within a month of incubation. Overall results indicated a high level of antibacterial activity of pyridine-based QACs.

Iwona Piątkowska-Chmiel, Monika Gawrońska-Grzywacz, Łukasz Popiołek et al.

Abstract Diabetes is a chronic disease leading to memory difficulties and deterioration of learning abilities. The previous studies showed that modulation of inflammatory pathways in the diabetic brain may reduce dysfunction or cell death in brain areas which are important for control of cognitive function. In the present study, we investigated the neuroprotective actions of newly synthesized adamantane derivatives on diabetes-induced cognitive impairment in mice. Our study relied on the fact that both vildagliptin and saxagliptin belong to DPP4 inhibitors and, contain adamantanyl group. Efficacy of tested compounds at reversing diabetes-induced different types of memory impairment was evaluated with the use of selected behavioural tests. The following neuroinflammatory indicators were also analyzed: neuroinflammatory indicators and the expression of genes involved in the inflammatory response of brain (Cav1, Bdnf). Our study demonstrated that new adamantane derivatives, similarly to DPP4 inhibitors, can restrict diabetes-induced cognitive deficits. We demonstrated that the overexpression of GLP-1-glucagon-like peptide as well as Bdnf, Cav1 genes translate into central blockade of pro-inflammatory synthesis of cytokines and significantly improvement on memory performance in diabetes mice. Newly synthesized adamantane derivatives might have important roles in prevention and treatment of cognitive impairment by inflammatory events in patients with diabetes or related diseases.

Saul Vislei Simões da Silva, Orlando Maia Barboza, Jéssica Teles Souza et al.

Quercetin (Q) is a bioflavonoid with biological potential; however, poor solubility in water, extensive enzymatic metabolism and a reduced bioavailability limit its biopharmacological use. The aim of this study was to perform structural modification in Q by acetylation, thus, obtaining the quercetin pentaacetate (Q5) analogue, in order to investigate the biological potentials (antioxidant, antileishmania, anti-inflammatory and cytotoxicity activities) in cell cultures. Q5 was characterized by FTIR, ¹H and ¹³C NMR spectra. The antioxidant potential was evaluated against the radical ABTS^•+. The anti-inflammatory potential was evaluated by measuring the pro-inflammatory cytokine tumor necrosis factor (TNF) and the production of nitric oxide (NO) in peritoneal macrophages from BALB/c mice. Cytotoxicity tests were performed using the AlamarBlue method in cancer cells HepG2 (human hepatocarcinoma), HL-60 (promyelocytic leukemia) and MCR-5 (healthy human lung fibroblasts) as well as the MTT method for C6 cell cultures (rat glioma). Q and Q5 showed antioxidant activity of 29% and 18%, respectively, which is justified by the replacement of hydroxyls by acetyl groups. Q and Q5 showed concentration-dependent reductions in NO and TNF production (<i>p</i> < 0.05); Q and Q5 showed higher activity at concentrations > 40µM when compared to dexamethasone (20 µM). For the HL-60 lineage, Q5 demonstrated selectivity, inducing death in cancer cells, when compared to the healthy cell line MRC-5 (IC₅₀ > 80 µM). Finally, the cytotoxic superiority of Q5 was verified (IC₅₀ = 11 µM), which, at 50 µM for 24 h, induced changes in the morphology of C6 glioma cells characterized by a round body shape (not yet reported in the literature). The analogue Q5 had potential biological effects and may be promising for further investigations against other cell cultures, particularly neural ones.

Manel Khiat, Fatima-Zohra Zradni, Souad Kasmi-Mir et al.

An electrochemical study using the cyclic voltammetry method was carried out on some previously prepared merocyanines salts, namely thiazolideniumsulfonate salts 5a-b, and thiazolidenium chloride salts 6a-b, and merocarbocyanines salts, namely alkylidenthiazolidenium sulfonate salt 5c, and alkylidenthiazolidenium chloride salt 6c. These salts are transformed by dimerization in situ in a voltammetric cell into tetrathiatetraazafulvalenes (TTTAFs) 7a-b, 7’a-b, 8c, and 8'c supposed to be π-electron donor molecules due to the existing conjugation in their structure. The structure of all new chemically synthesized molecules was confirmed by IR, 1H-NMR, 13C-NMR, and MS. The transformation of salts into TTTAF was confirmed by a reversible voltammogram curve and the variation of observed potentials.

Hee-Sung Chae, Sun Young Kim, Pisey Pel et al.

Cough and phlegm frequently occur in respiratory diseases like upper respiratory tract infections, acute bronchitis, and chronic obstructive pulmonary diseases. To relieve these symptoms and diseases, various ingredients are being used despite the debates on their clinical efficacy. We aimed to investigate the effects of the extract CKD-497, composed of Atractylodis Rhizoma Alba and Fructus Schisandrae, in relieving cough and facilitating expectoration of phlegm. CKD-497 was found to inhibit inflammatory mediators such as interleukin-8 (IL-8) and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-treated mouse macrophages and transient receptor potential cation channel 1 (TRPV-1)-overexpressed human bronchial epithelial cells stimulated by capsaicin. CKD-497 decreased the viscosity of the mucin solution. During in vivo experiments, CKD-497 reduced coughing numbers and increased expectoration of phlegm via mucociliary clearance enhancement. Collectively, these data suggest that CKD-497 possesses potential for cough and phlegm expectoration treatment.

Wei Ding, Tingyan Liu, Xiao Bi et al.

Background/Aims: Growing evidence suggests mitochondrial dysfunction (MtD) and the Nlrp3 inflammasome play critical roles in chronic kidney disease (CKD) progression. We previously reported that Aldosterone (Aldo)-induced renal injury in vitro is directly caused by mitochondrial reactive oxygen species (mtROS)-mediated activation of the Nlrp3 inflammasome. Here we aimed to determine whether a mitochondria-targeted antioxidant (Mito-Tempo) could prevent Aldo-induced kidney damage in vivo. Methods: C57BL/6J mice were treated with Aldo and/or Mito-Tempo (or ethanol as a control) for 4 weeks. Renal injury was evaluated by Periodic Acid-Schiff reagent or Masson’s trichrome staining and electron microscopy. ROS were measured by DCFDA fluorescence and ELISA. MtD was determined by real-time PCR and electron microscopy. Activation of the Nlrp3 inflammasome and endoplasmic reticulum stress (ERS) was detected via western blot. Results: Compared with control mice, Aldo-infused mice showed impaired renal function, increased mtROS production and MtD, Nlrp3 inflammasome activation, and elevated ERS. We showed administration of Mito-Tempo significantly improved renal function and MtD, and reduced Nlrp3 inflammasome activation and ERS in vivo. Conclusion: Mitochondria-targeted antioxidants may attenuate Aldo-infused renal injury by inhibiting MtD, the Nlrp3 inflammasome, and ERS in vivo. Therefore, targeting mtROS might be an effective strategy for preventing CKD.

Najoua Msilini, Ines Guesmi, Mohamed Chebbi et al.

The effects of NO3- nutrition on iron deficiency responses were investigated in Arabidopsis thaliana. Plants were grown with or without 5 µM Fe, and with NO3- alone or a mixture of NO3- and NH4+. The results indicated that, NO3- nutrition induced higher dry matter production, regardless the Fe concentration. Fe deficiency reduced growth activity, photosynthetic pigment concentration and Fe content of plants, whatever the N forms. This decrease was more pronounced in plants grown with mixed N source; those plants presented the highest EL and MDA and anthocyanin contents compared to plants grown under Fe sufficient conditions. In iron free-solutions, with NO3- as the sole nitrogen source, enhanced FC-R activity in the roots was observed. However, in the presence of NH4+, plants displayed some decrease in in FC-R and PEPC activities. The presence of NH4+ modified typical Fe stress responses in Arabidopsis thaliana plants.

Amuri Kilonda, Babady-Bila, Osomba Lohohola et al.