Effect of metal deposition on the photocatalytic activity of titania-silica for the removal of 2-propanol diluted in water

The influence of transition metals, such as Ag, Cr, and Co, on the photocatalytic properties of titania-silica (TiO₂-SiO₂) prepared via both impregnation (imp) and photo-assisted deposition (PAD) methods has been investigated. The decomposition of 2-propanol under UV-light irradiation was used to probe the effect of transition metals deposition on the activity of titania-silica. PAD-Ag/TiO₂-SiO₂ prepared by the PAD method was highly active compared to the original TiO₂-SiO₂, while imp-Cr/TiO₂-SiO₂ prepared by conventional impregnation method showed a weak tendency toward the decomposition of 2-propanol.     

Hybrid Nanoparticle Film Material

A new hybrid material consisting of a nanoparticle film on a flexible, porous substrate is formed. The hybrid nanoparticle films are non-redispersable in solvents, yet remain porous and flexible. Visually, the hybrid films are highly reflective and metallic gold in appearance. However, the electronic properties of the films are characteristic for materials made from separate, non-sintered nanoparticles. Films of large area (several tens of cm²) and several microns in thickness can be formed. The method of formation is based on cross-linking gold nanoparticles using alkane-dithiols followed by filtration onto nanoporous supports. The films were characterized by transmission electron microscopy, atomic force microscopy and resistance measurements. The effect of the ratio of alkane-dithiol cross-linker to gold nanoparticles on the resistance of the nanoparticle films was also studied.     

Leveraging autocatalytic reactions for chemical domain image classification

Autocatalysis is fundamental to many biological processes, and kinetic models of autocatalytic reactions have mathematical forms similar to activation functions used in artificial neural networks. Inspired by these similarities, we use an autocatalytic reaction, the copper-catalyzed azide–alkyne cycloaddition, to perform digital image recognition tasks. Images are encoded in the concentration of a catalyst across an array of liquid samples, and the classification is performed with a sequence of automated fluid transfers. The outputs of the operations are monitored using UV-vis spectroscopy. The growing interest in molecular information storage suggests that methods for computing in chemistry will become increasingly important for querying and manipulating molecular memory.

Kinetic models of autocatalytic reactions have mathematical forms similar to activation functions used in artificial neural networks. Inspired by these similarities, we use a copper-catalyzed reaction to perform digital image recognition tasks.     

Holospiniferoside: A New Antitumor Cerebroside from The Red Sea Cucumber Holothuria spinifera: In Vitro and In Silico Studies

Chemical investigation of the methanolic extract of the Red Sea cucumber Holothuria spinifera led to the isolation of a new cerebroside, holospiniferoside (1), together with thymidine (2), methyl-α-d-glucopyranoside (3), a new triacylglycerol (4), and cholesterol (5). Their chemical structures were established by NMR and mass spectrometric analysis, including gas chromatography–mass spectrometry (GC–MS) and high-resolution mass spectrometry (HRMS). All the isolated compounds are reported in this species for the first time. Moreover, compound 1 exhibited promising in vitro antiproliferative effect on the human breast cancer cell line (MCF-7) with IC₅₀ of 20.6 µM compared to the IC₅₀ of 15.3 µM for the drug cisplatin. To predict the possible mechanism underlying the cytotoxicity of compound 1, a docking study was performed to elucidate its binding interactions with the active site of the protein Mdm2–p53. Compound 1 displayed an apoptotic activity via strong interaction with the active site of the target protein. This study highlights the importance of marine natural products in the design of new anticancer agents.     

Non-particulate (continuous bed or monolithic) restricted-access reversed-phase media for sample clean-up and separation by capillary-format liquid chromatography

Restricted-access reversed-phase non-particulate (continuous bed or monolithic) stationary phases of different hydrophobicity synthesized in 100 m i.d. fused silica capillaries have been evaluated. A specific property of restricted-access media (RAM) is that they interact with small analytes and exclude big molecules, e.g. proteins, from access to the active sites and adsorption on the surface. This dual property facilitates direct injection of biological fluids for drug or drug-metabolite analysis. Different RAM and RAM-precursor capillary columns were tested to assess the influence of chromatographic bed morphology on loadability. Inverse size-exclusion chromatography was used for investigation of pore structural properties of the capillary-format continuous beds. The data obtained were used to discuss the mechanism of separation of the biological samples using capillary columns and to propose a model for the topochemical architecture of the RAM investigated. Different morphology of the non-particulate reversed-phase precursors resulted in two types of RAM material shielded with hydrophilic polymer, classified as homogeneous or heterogeneous topochemistry stationary phases. Capillary columns were applied for chromatography of biological fluids. High resolution was obtained, without the need for column switching, when capillary columns operated in gradient conditions. Extensive evaluation of the chromatographic properties (hydrophobicity, efficiency, separation impedance, and loadability) of the non-particulate reversed-phase materials was performed before and after shielding with hydrophilic polymer to generate restricted-access properties. Minor changes of hydrophobicity, efficiency, or separation impedance were observed after the shielding.     

RAFT mediated polysaccharide copolymers

Graft copolymers were prepared using the RAFT process via a Z-group approach, where xanthate esters were formed directly on a cellulosic substrate. Grafting of vinyl acetate onto the modified cellulosic materials was then carried out via the reversible addition fragmentation chain transfer (RAFT) process. The xanthate RAFT agents on the backbone of the cellulosic materials were identified by Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-vis). The number average molar masses of the graft copolymers were determined using size exclusion chromatography (SEC) and further characterization was conducted via liquid adsorption chromatography (LAC). The chromatographic results showed that the modified cellulosic materials were successfully grafted with polyvinyl acetate in a controlled manner. Grafted polyvinyl acetate (on the surface) and nongrafted polyvinyl acetate (in the solution) have almost the same molar mass and polydispersity index.     

Synthetic Routes to Coumarin(Benzopyrone)-Fused Five-Membered Aromatic Heterocycles Built on the α-Pyrone Moiety. Part II: Five-Membered Aromatic Rings with Multi Heteroatoms

Coumarins are natural heterocycles that widely contribute to the design of various biologically active compounds. Fusing different aromatic heterocycles with coumarin at its 3,4-position is one of the interesting approaches to generating novel molecules with various biological activities. During our continuing interest in assembling information about fused five-membered aromatic heterocycles, and after having presented mono-hetero-atomic five-membered aromatic heterocycles in Part I. The current review Part II is intended to present an overview of the different synthetic routes to coumarin (benzopyrone)-fused five-membered aromatic heterocycles with multi-heteroatoms built on the pyrone ring, covering the literature from 1945 to 2021.     

Application of the Second Born Approximation to Excitation of Hydrogen Atoms by Protons and Antiprotons Impact

We present and compare total cross sections for excitation in collisions of protons and antiprotons with hydrogen atoms in the 2s state. Calculations axe performed in the framework of the second Born approximation, in the energy range of 5-1000 keV. We apply the usual approach of the second Born approximation, which approximates the summation raised by retaining few terms, as well as another approach approximates all energies corresponding to the intermediate states to that corresponding to the initial state. The annihilation effect in the case of the antiproton collision is investigated. We compare the results with the previous theoretical calculations.     

A novel biosensor for early diagnosis of liver cancer cases using smart nano‐magnetic metal–organic framework

For the first time, alpha‐fetoprotein (AFP) quantification as an early test for liver cancer diagnosis competing with other interfering analytes and factors based on a novel nano‐magnetic metal–organic framework (MOF) was investigated. The novel nano‐magnetic MOF was synthesized via a simple preparation method, and characterized using various techniques. The X‐ray photoelectron spectrum of the nano‐magnetic MOF shows Cu 2p, O 1s, N 1s and C 1s peaks that evidence the presence of these elements in the sample without any impurities. Scanning and transmission electron microscopy images show the nano‐magnetic MOF with average size between 22 and 43 nm. The results of a photoluminescence study show that the nano‐magnetic MOF exhibits strong emission at 418 nm after excitation at 354 nm. Moreover, a Stern–Völmer graph shows a linear calibration curve over an AFP concentration range 1.0–520 ng ml^?1 with a correlation coefficient of 0.997, detection limit of 1.18 ng ml^?1 and quantitation limit of 3.58 ng ml^?1. According to the marked quenching of the photoluminescence intensity of the nano‐magnetic MOF using various concentrations of AFP, it was successfully used as a biosensor for AFP in serum samples collected from hepatitis patients in addition to healthy males and females. The quenching mechanism was well studied, and found to be a dynamic type. The present work offers a simple, low‐cost, room‐temperature and rapid technique, being non‐time‐consuming, highly accurate, selective and highly sensitive compared with most published methods.