Hasil untuk "Organic chemistry"

R. Berger, G. Resnati, P. Metrangolo et al.

V. Zhdankin, P. Stang

N. Berova, L. di Bari, G. Pescitelli

D. Fox

O. Yaghi, Hailian Li, Charles E. Davis et al.

Kevin C. Jones, P. Voogt

H. Katz, and Zhenan Bao, Sylvain L. Gilat

T. Hasegawa, E. Herbst, C. Leung

Faezeh Firuzpour, Maryam Barancheshmeh, Fariba Fallah Ziarani et al.

Background: Breast cancer (BC) remains a global health emergency, particularly HER2-positive subtypes, which are aggressive and resistant to conventional therapies. Despite advancements, therapeutic resistance and limited immune memory underline the need for novel treatment approaches such as multi-epitope vaccines. Objective: This study investigates the design and effectiveness of a novel in silico multi-epitope vaccine that is capable of targeting HER2 in breast cancer using immunoinformatics, structural modeling, and immune simulation approaches. Methods: UniProt was used to retrieve the HER2 protein sequences. Cytotoxic Tlymphocyte (CTL) and helper T lymphocyte (HTL) epitopes were predicted using IEDB and CTLPred, and filtered for antigenicity, IFN-γ production, and population coverage. The vaccine construct was designed by linking selected epitopes to PADRE, TAT peptide, and adjuvants using appropriate linker sequences. An evaluation of physicochemical, allergenic, and toxicological properties was carried out on the 322-amino-acid vaccine construct. Secondary and tertiary structures were predicted using PSIPRED and Robetta, refined with GalaxyRefine, and validated through Ramachandran plots, ERRAT, and ProSA-web. Molecular docking with TLR4 was conducted using HDOCK. Molecular dynamics simulations (MD) were performed with GROMACS for 100 ns and analyzed using RMSD, RMSF, PCA, DCCM, and MM-PBSA. Immune simulations were performed using C-ImmSim. Results: The final vaccine construct was found to be non-allergenic, antigenic (VaxiJen score: 0.59) and stable (instability index: 23.18). Tertiary structure validation yielded a favorable Ramachandran distribution (83 %), an ERRAT score of 90.12, and a Z-score of −8.35. Docking showed strong binding to TLR4 (score:296.23, with 6 ion bridges and 7 hydrogen bonds). Stable conformation of the vaccine construct with low fluctuations and high interaction correlation was derived through MD simulations. MM-PBSA calculated a binding free energy of −112.71 kJ/mol. Immune simulations predicted robust humoral and cellular immune responses with increased IFN-γ, IL-2, CTLs, and memory B-cells. Conclusion: The proposed HER2-targeted multi-epitope vaccine confirmed promising immunogenicity, structural stability, and potential global population coverage. It represents a novel, rationally designed immunotherapy candidate against HER2-positive breast cancer. However, further in vitro and in vivo validations are required to confirm its clinical application.

Maciej Combrzyński, Jakub Soja, Michał Staniak et al.

Functional foods represent a new and thriving area of research. A significant direction of these studies is based on new products containing edible house cricket-derived additives. The aim of the presented studies was to determine the effect of using cricket powder (at 10% and 30% content) on the extrusion cooking parameters and the nutritional value, antioxidant activity, and selected physical properties of extruded potato-based snack pellets. The results suggest that house cricket powder is a promising functional ingredient. The processing efficiency and the physical and functional properties of the extrudates, including SME, WAI, WSI, bulk density, and mechanical durability, were affected by the addition of cricket powder, screw speed, and moisture content. Generally, higher levels of cricket powder reduced processing efficiency and altered structural properties due to changes in composition, particularly the balance between protein, fiber, and starch. The addition of cricket powder significantly improved antioxidant activity (>94% of DPPH scavenging for 30% content of additive) and increased the total polyphenol content in the assessed samples in comparison to potato bases (212.3 and 21.7 μg GAE/g dry weight, respectively). These innovative snack pellets containing cricket powder could be an appealing option due to their potential health benefits.

Khurram Shahzad Munawar, Afshan Rizwan, Syed Mustansar Abbas et al.

Ligand, its sodium salt and four new metals (Zn (II), Cu (II), VO(IV) and Cd (II)) carboxylate complexes have been prepared and characterized by FT-IR, conductometry, and UV-visible spectroscopy. The prepared compounds are pure and obtained in the solid state. They have sharp melting points and have good yield. FT-IR spectroscopy proved that carbonyl and amine groups are not involved in metal-ligand coordination. The ligand was coordinated through the carboxylic group upon complex formation. The molar conductance data reveals that the compounds exhibit non-electrolytic properties, primarily attributable to their notably low conductance values. A broad band in the FT-IR spectrum of copper complex represents the presence of water molecules. UV-visible spectral data proved that the synthesized compounds have shown π-π* and n-π* transitions, which indicated that all the compounds are aromatic. Various concentrations of the synthesized compounds were employed to investigate their inhibitory effect on the alkaline phosphatase (ALP) enzyme, conclusively demonstrating their ability to inhibit its activity.

Aicha Khemili, Djamel Bensizerara, Haroun Chenchouni et al.

Infectious diseases, including vector-borne and antibiotic-resistant infections, present significant global health challenges, necessitating the exploration of natural alternatives for disease control. In this study, we investigated the essential oil (EO) profile as well as larvicidal and antibacterial properties of two wild Apiaceae species used in Algeria: <i>Daucus carota</i> L. (DCEO) and <i>Foeniculum vulgare</i> Mill. (FVEO). EO was extracted from the aerial parts by steam distillation and analyzed using Gas Chromatography Mass Spectrometry (GC/MS). Major constituents identified in DCEO were geranyl acetate (50.07%) and elemicin (10.77%), while FVEO contained estragole (24.93%), fenchone (20.20%), and α-phellandrene (17.96%). Both EOs were highly effective towards <i>Culex pipiens</i> larvae, with low LC₅₀ values of 30.6 ± 1.06 ppm for DCEO and 34.7 ± 1.06 ppm for FVEO, indicating their potential as bioinsecticides due to their bioactivity and bioavailability. Additionally, the two Eos demonstrated moderate antibacterial efficacy against gram-positive bacteria, <i>Staphylococcus aureus</i> ATCC 25923 and <i>Staphylococcus aureus</i> MRSA ATCC 43300, respectively, with DCEO showing MIC values of 10 and 20 mg/mL, respectively, and FVEO exhibiting MIC values > 20 mg/mL. However, both EOs showed limited effectiveness against gram-negative bacteria, <i>Escherichia coli</i> ATCC 25922 and <i>Klebsiella pneumonia</i> ATCC 700603. These results highlight the potential applications of DCEO and FVEO as natural bioinsecticides and antibacterial agents, offering promising avenues for further research and development in pest control and food preservation.

S. Patai, Z. Rappoport

A. Grimsdale, K. Müllen

Jia Li, Shanliang Zheng

Currently, international nuclear fission reactors producing medical isotopes face the problem of shutdown and maintenance, decommissioning, or dismantling, while the production capacity of domestic research reactors for medical radioisotopes is inadequate, and the supply capacity for medical radioisotopes faces major challenges in the future. Fusion reactors are characterized by high neutron energy, high flux density, and the absence of highly radioactive fission fragments. Additionally, compared to fission reactors, the reactivity of the fusion reactor core is not significantly affected by the target material. By building a preliminary model of the China Fusion Engineering Test Reactor (CFETR), a Monte Carlo simulation was performed for particle transport between different target materials at a fusion power of 2 GW. The yields (specific activity) of six medical radioisotopes (¹⁴C, ⁸⁹Sr, ³²P, ⁶⁴Cu, ⁶⁷Cu, and ⁹⁹Mo) with various irradiation positions, different target materials, and different irradiation times were studied, and compared with those of other high-flux engineering test reactors (HFETR) and the China Experimental Fast Reactor (CEFR). The results show that this approach not only provides competitive medical isotope yield, but also contributes to the performance of the fusion reactor itself, e.g., tritium self-sustainability and shielding performance.

Paweł Sroka, Tomasz Tarko, Aleksandra Duda

Furfural is a naturally occurring compound in bee honey, classified as a fermentation inhibitor. The aim of this study was to ascertain the concentration of furfural in mead worts, prepared at room temperature (unsaturated) and heated to boiling for 10 to 70 min (saturated), with an extract of 25 to 45°Brix. Moreover, the impact of the furfural on the fermentation course of mead wort was assessed. For this purpose, fermentation tests were conducted using mead wort (30°Brix) to which furfural was added at concentrations ranging from 1 to 100 mg/L. HS-SPME-GC-TOF-MS analysis revealed that the furfural concentration in mead worts varied between 2.3 and 5.3 mg/L. In saturated worts, the concentration increased by 2.8 to 4.5 times. Acidification of mead wort prior to boiling led to further increase in furfural concentration. The greatest changes occurred in the least concentrated worts, having the lowest buffer capacity. The addition of furfural to the mead wort did not inhibit fermentation, and an increase in attenuation was observed in the samples containing 2 mg/L of furfural compared to the control. Throughout the fermentation most of the furfural was reduced to furfuryl alcohol.

M. Brook

CHEN Xi1,2, LI Tong-zhou1, ZHU Zheng-jiang1

Metabolomics aims to systematically profile various small molecules (i.e., metabolites and lipids) in biological samples. Compared with genomics, transcriptomics and proteomics, metabolomics locates in the downstream of omics technologies, which links genotype with phenotype. Metabolomics is an important part of system biology. It has been widely applied to discover diagnostic biomarkers and understand disease pathogenesis. Due to the high structure diversity and numerous isomers of metabolites and lipids, high-accuracy and high-coverage analysis of complex biological samples remain the bottleneck for comprehensive metabolomics analysis. Recently, ion mobility-mass spectrometry (IM-MS) has emerged as a promising technology for metabolomics. Ion mobility is a separation technology for gas phase. The multiple collisions between ions and neutral buffer gas under the influence of an electric field in mobility cell were utilized to rapidly separate ions with different sizes, shapes and charges. Compared with traditional separation method (i.e., gas phase separation and liquid chromatography separation), this method can increase the peak capacity, reduce noisy signals, improve sensitivity and selectivity. More importantly, the collision cross section (CCS) value derived from IM-MS is a new physio-chemical property to aid the annotation of chemical structures of known and unknown metabolites. CCS value is high reproducibility among different labs and instruments, which is suitable to be standardized for database establishment and wide application on metabolomics analysis. Therefore, it is important to ensure the accurate CCS measurement and develop high coverage CCS database for metabolomics. There are three major types of commercially available ion mobility-mass spectrometers, including time-dispersive, spatial-dispersive, and confinement and selective release. Due to different instrument design, the CCS value calculation and calibration methods are different. It is necessary to use the appropriate calibration solutions and methods for CCS measurement. Recently, CCS databases for small molecules have been established, which can be classified as two types of experimental measurement and in silico curation. Metabolite standard was usually used to acquire the accurate experimental CCS values. However, the number of available metabolite standards limits the coverage of CCS database. Instead, with the progress of theoretical calculation and machine learning, CCS values significantly expand the coverage of CCS database in silico curation, which are also accurate enough for metabolites identification. In this review, the basic principles of commercial IM-MS instruments that commonly used for metabolomics were introduced. Then, the experimental measurement and calibration of CCS values for different IM-MS instruments were summarized. The available CCS databases used for metabolomics were demonstrated. Finally, the applications of CCS values to support metabolomics were discussed.

Nina K. Plugotarenko, Tatiana N. Myasoedova, Sergey P. Novikov et al.

Signals from resistive gas sensors based on zirconium dioxide and silicon–carbon films have been extensively investigated to estimate gas concentration. In this study, the change in the normalized resistance of the sensor’s response under NO₂ exposure is shown and the analysis of the first and second derivatives of the response curves were carried out. A signal-processing scheme, reducing the effect of noise and signal drift, is proposed. The extreme of the second derivative of the sensor response, the initial reaction rate, and the slope of the curve of the approximating line in the coordinates of the Elovich equation are proposed as calibration dependencies. The calibration curves built from the values of the maximum second derivative turned out to be the most stable, with the lowest relative error in estimating gas concentration compared to the traditional fixed-time point method.

Maria Michela Salvatore, Ilaria Di Lelio, Marina DellaGreca et al.

An undescribed 5,6-dihydropyran-2-one, namely diplopyrone C, was isolated and characterized from the cultures of an isolate of the fungus <i>Diplodia corticola</i> recovered from <i>Quercus suber</i> in Algeria. The structure and relative stereostructure of (5<i>S</i>,6S,7<i>Z</i>,9<i>S</i>,10<i>S</i>)-5-hydroxy-6-(2-(3-methyloxiran-2-yl)vinyl)-5,6-dihydro-2H-pyran-2-one were assigned essentially based on NMR and MS data. Furthermore, ten known compounds were isolated and identified in the same cultures. The most abundant product, the tetracyclic pimarane diterpene sphaeropsidin A, was tested for insecticidal effects against the model sucking aphid, <i>Acyrthosiphon pisum</i>. Results showed a toxic dose-dependent oral activity of sphaeropsidin A, with an LC₅₀ of 9.64 mM.