Small compounds based on 2,7-silafluorene and 4,7-di (2′-thienyl) for heterojunction organic solar cells: DFT study

To understand the effect of the substitution by several strong electron-withdrawing groups ([1,2,5]thiadiazolo[3,4-g]quinoxaline; benzo[c][1,2,5]thiadiazole and quinoxaline) and end-capped donor groups (thiophene and phenyl) on the structural and optoelectronic properties of six conjugated compounds C1–C6 based on 2,7-silafluorene and 4,7-di (2′-thienyl) used for organic solar cells application such as bulk heterojunction (BHJ) solar cell. We have done a theoretical study to calculate and predict these properties. The electronic structures and optical absorption spectra of donors were calculated using density functional theory, and the Zerner’s intermediate neglect of differential overlap functional theory level is employed to investigate the excited singlet states, respectively, and to shed light on how the substitution and the pi-conjugation order influence the performance of these compounds in the BHJ cell. Moreover, the theoretical results including optoelectronic and photovoltaic properties of the compound C1 are in good agreement with the available experimental data extracted from bibliography. The calculated results of these molecules reveal that the compounds C3 and C6, with the [1,2,5]thiadiazolo[3,4-g]quinoxaline as electron acceptor seem to be good candidates materials for photovoltaic applications due to their best optoelectronic and photovoltaic properties.     

Studies on the Zymogram Method for the Detection of Pectinolytic Activities Using CTAB

Zymogram analysis is a useful tool for the identification of several enzymes. The present study was undertaken to investigate the efficiency gains from the characterization of pectic enzymes on zymograms by staining of pectin-agarose overlays using cetyl trimethyl ammonium bromide also known as cetrimide or CTAB. The method is based on the fact that the enzymatic hydrolysis of the pectic substrates included in the agarose matrix gel inhibited their precipitation by CTAB, leading to the appearance of cleared zones in front of the pectin hydrolases and lyases. Conversely, esterases led to the increase of pectin precipitation. Fungal pectinolytic enzymes were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to the zymogram detection technique, using two pectin substances, namely citrus pectin and polygalacturonic acid. Overall, the findings presented in the current study indicate that several elements (ions, salts, pH, temperature, chelators, and reducing agents) may significantly affect the results of zymogram analysis and can, therefore, be employed to enhance the discriminatory and operational potential of the analysis in terms of accurate discrimination between several pectinolytic activities involved and effective implementation of the purification procedures required in the process.     

Competition between covalent and noncovalent bond cleavages in dissociation of phosphopeptide-amine complexes

Interactions between quaternary amino or guanidino groups with anions are ubiquitous in nature and have been extensively studied phenomenologically. However, little is known about the binding energies in non-covalent complexes containing these functional groups. Here, we present a first study focused on quantifying such interactions using complexes of phosphorylated A(3)pXA(3)-NH(2) (X = S, T, Y) peptides with decamethonium (DCM) or diaguanidinodecane (DGD) ligands as model systems. Time- and collision energy-resolved surface-induced dissociation (SID) of the singly charged complexes was examined using a specially configured Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS). Dissociation thresholds and activation energies were obtained from RRKM modeling of the experimental data that has been described and carefully characterized in our previous studies. For systems examined in this study, covalent bond cleavages resulting in phosphate abstraction by the cationic ligand are characterized by low dissociation thresholds and relatively tight transition states. In contrast, high dissociation barriers and large positive activation entropies were obtained for cleavages of non-covalent bonds. Dissociation parameters obtained from the modeling of the experimental data are in excellent agreement with the results of density functional theory (DFT) calculations. Comparison between the experimental data and theoretical calculations indicate that phosphate abstraction by the ligand is rather localized and mainly affected by the identity of the phosphorylated side chain. The hydrogen bonding in the peptide and ligand properties play a minor role in determining the energetics and dynamics of the phosphate abstraction channel.     

Correlations on Phenolic Screening Related to In Vitro and In Ovo Assessment of Ocimum basilicum L. Hydro-Alcoholic Extracts Used as Skin Active Ingredient

The current study was aimed to evaluate the phenolic composition parameters of two hydro-alcoholic extracts of Ocimum basilicum L. (OB) obtained from the aerial part (without leaves) and leaves, in order to determine their contribution to the antioxidant activity (AOA). Both hydro-alcoholic extracts have proven to be rich in polyphenolic compounds, flavonoids, flavonols and tannins. Therefore, the leaves’ extracts reveal an inhibition percentage of 89%, almost comparable with the standard reference (95%). To complete the toxicological profile, the study also assessed the potential cytotoxicity of basil hydro-alcoholic extracts on immortalized human keratinocytes (HaCaT), skin human fibroblasts (1BR3), mice epidermis (JB6Cl41-5a) and primary human melanocytes (HEMa) cells, correlated to A375 antitumor in vitro activity. The extracts did not induce significant cytotoxic effect on any of the selected normal cell lines but showed relevant activity on A375 cells. Considering the low values obtained regarding the irritative effects in the chorionallantoic membrane of the egg on blood vessels, we can emphasize that both extracts can be considered as biocompatible ingredients. Regarding the potential activity of hydro-alcoholic extracts on human skin, the decrease of erythema values after the application of extracts was a relevant observation which indicates the anti-inflammatory potential of Ocimum basilicum L.     

N-Octyl Quaternized P4VP Interaction With Orange Telon

The removal of orange Telon from aqueous solutions by poly(N-octyl-4-vinylpyridiniumbromide) copolymer was investigated. Batch adsorption experiments were carried out to study the effect of experimental parameters on the orange Telon adsorption equilibrium. The adsorption characteristics of copolymer to ward orange Telon in dilute aqueous solution were followed using UV-Vis spectrophotometry. Adsorption equilibrium was reached within 60 min for 0.03 g of poly(4-vinylpyridine quaternized at 58%. The kinetic of adsorption is best described by a pseudo-second-order model. Results also showed that the equilibrium modeling of orange Telon removal process was described by Langmuir isotherms. The maximum adsorption capacity determined from the Langmuir isotherm was 76.4 mg g^{? 1}. The study of the thermodynamic parameters showed that the adsorption of orange Telon on copolymer is an exothermic process and the randomness decreases at the solid-solution interface during the adsorption of dye on the copolymer.     

Sol-Gel Synthesized High Entropy Metal Oxides as High-Performance Catalysts for Electrochemical Water Oxidation

Hexanary high-entropy oxides (HEOs) were synthesized through the mechanochemical sol-gel method for electrocatalytic water oxidation reaction (WOR). As-synthesized catalysts were subjected to characterization, including X-ray diffraction (XRD), Fourier transforms infrared (FTIR) analysis, and scanning electron microscopy (SEM). All the oxide systems exhibited sharp diffraction peaks in XRD patterns indicating the defined crystal structure. Strong absorption between 400–700 cm⁻¹ in FTIR indicated the formation of metal-oxide bonds in all HEO systems. WOR was investigated via cyclic voltammetry using HEOs as electrode platforms, 1M KOH as the basic medium, and 1M methanol (CH₃OH) as the facilitator. Voltammetric profiles for both equiatomic (EHEOs) and non-equiatomic (NEHEOs) were investigated, and NEHEOs exhibited the maximum current output for WOR. Moreover, methanol addition improved the current profiles, thus leading to the electrode utility in direct methanol fuel cells as a sequential increase in methanol concentration from 1M to 2M enhanced the OER current density from 61.4 to 94.3 mA cm⁻² using NEHEO. The NEHEOs comprising a greater percentage of Al, ([Al_0.35(Mg, Fe, Cu, Ni, Co)_0.65]₃O₄) displayed high WOR catalytic performance with the maximum diffusion coefficient, D° (10.90 cm² s⁻¹) and heterogeneous rate constant, k° (7.98 cm s⁻¹) values. These primary findings from the EC processes for WOR provide the foundation for their applications in high-energy devices. Conclusively, HEOs are proven as novel and efficient catalytic platforms for electrochemical water oxidation.     

Improved Method for Preparation of 3-(1H-Indol-3-yl)benzofuran-2(3H)-ones

3-(1H-Indol-3-yl)benzofuran-2(3H)-ones were efficiently accessed via polyphosphoric acid-mediated condensation of 3-(2-nitrovinyl)-1H-indoles with phenols.     

Surface modification of resorcinarene based self-assembled solid lipid nanoparticles for drug targeting

Prolyl-bearing amphiphilic resorcinarenes, e.g. tetrakis(N-methylprolyl)tetraundecylcalix[4]resorcinarene, self-assemble as stable solid lipid nanoparticles; these fully characterized systems could be further functionalized at their surface with proteins, and interact with specific antibodies bound on a sensor surface.