Electric dipole (hyper)polarizabilities of spatially confined LiH molecule

In this study we report on the electronic contributions to the linear and nonlinear static electronic electric dipole properties, namely the dipole moment (μ), the polarizability (α), and the first-hyperpolarizability (β), of spatially confined LiH molecule in its ground X (1)Σ(+) state. The finite-field technique is applied to estimate the corresponding energy and dipole moment derivatives with respect to external electric field. Various forms of confining potential, of either spherical or cylindrical symmetry, are included in the Hamiltonian in the form of one-electron operator. The computations are performed at several levels of approximation including the coupled-cluster methods as well as multi-configurational (full configuration interaction) and explicitly correlated Gaussian wavefunctions. The performance of Kohn-Sham density functional theory for the selected exchange-correlation functionals is also discussed. In general, the orbital compression effects lead to a substantial reduction in all the studied properties regardless of the symmetry of confining potential, however, the rate of this reduction varies depending on the type of applied potential. Only in the case of dipole moment under a cylindrical confinement a gradual increase of its magnitude is observed.     

Adsorption of modified dextrins on molybdenite: AFM imaging, contact angle, and flotation studies

The adsorption of three dextrins (a regular wheat dextrin, Dextrin TY, carboxymethyl (CM) Dextrin, and hydroxypropyl (HP) Dextrin) on molybdenite has been investigated using adsorption isotherms, tapping mode atomic force microscopy (TMAFM), contact angle measurements, and dynamic bubble-surface collisions. In addition, the effect of the polymers on the flotation recovery of molybdenite has been determined. The isotherms revealed the importance of molecular weight in determining the adsorbed amounts of the polymers on molybdenite at plateau coverage. TMAFM revealed the morphology of the three polymers, which consisted of randomly dispersed domains with a higher area fraction of surface coverage for the substituted dextrins. The contact angle of polymer-treated molybdenite indicated that polymer layer coverage and hydration influenced the mineral surface hydrophobicity. Bubble-surface collisions indicated that the polymers affected thin film rupture and dewetting rate differently, correlating with differences in the adsorbed layer morphology. Direct correlations were found between the surface coverage of the adsorbed layers, their impact on thin film rupture time, and their impact on flotation recovery, highlighting the paramount role of the polymer morphology in the bubble/particle attachment process and subsequent flotation.     

Enhanced adsorption of paracetamol on closed carbon nanotubes by formation of nanoaggregates: carbon nanotubes as potential materials in hot-melt drug deposition-experiment and simulation

We present the new results of systematic studies of paracetamol adsorption on closed, commercially available, unmodified carbon nanotubes. The results of thermal analysis, static adsorption measurements and the comparison with phenol adsorption data lead to suggestion that the formation of paracetamol nanoaggregates in the interstitial spaces between nanotubes occurs. This effect is also confirmed by the results of (performed in two ways) independent dynamic measurements and by molecular dynamics simulation technique. Next, we show that the behavior of adsorbed paracetamol during heating leads to the creation of a new drug delivery system. The properties of this system depend on the type of applied nanotubes and the parameters of the process called hot-melt drug deposition. Thus, we conclude that confined nanoaggregate formation, as well as hot-melt deposition should be promising effects in the preparation of highly effective, new drug delivery systems.     

Precursor-Boosted Production of Metabolites in Nasturtium officinale Microshoots Grown in Plantform Bioreactors,and Antioxidant and Antimicrobial Activities of Biomass Extracts

The study demonstrated the effects of precursor feeding on the production of glucosinolates (GSLs), flavonoids, polyphenols, saccharides, and photosynthetic pigments in Nasturtium officinale microshoot cultures grown in Plantform bioreactors. It also evaluated the antioxidant and antimicrobial activities of extracts. L-phenylalanine (Phe) and L-tryptophan (Trp) as precursors were tested at 0.05, 0.1, 0.5, 1.0, and 3.0 mM. They were added at the beginning (day 0) or on day 10 of the culture. Microshoots were harvested after 20 days. Microshoots treated with 3.0 mM Phe (day 0) had the highest total GSL content (269.20 mg/100 g DW). The qualitative and quantitative profiles of the GSLs (UHPLC-DAD-MS/MS) were influenced by precursor feeding. Phe at 3.0 mM stimulated the best production of 4-methoxyglucobrassicin (149.99 mg/100 g DW) and gluconasturtiin (36.17 mg/100 g DW). Total flavonoids increased to a maximum of 1364.38 mg/100 g DW with 3.0 mM Phe (day 0), and polyphenols to a maximum of 1062.76 mg/100 g DW with 3.0 mM Trp (day 0). The precursors also increased the amounts of p-coumaric and ferulic acids, and rutoside, and generally increased the production of active photosynthetic pigments. Antioxidant potential increased the most with 0.1 mM Phe (day 0) (CUPRAC, FRAP), and with 0.5 mM Trp (day 10) (DPPH). The extracts of microshoots treated with 3.0 mM Phe (day 0) showed the most promising bacteriostatic activity against microaerobic Gram-positive acne strains (MIC 250–500 µg/mL, 20–21 mm inhibition zones). No extract was cytotoxic to normal human fibroblasts over the tested concentration range (up to 250 μg/mL).     

Interaction of Liposomal Formulations of Meta-tetra(hydroxyphenyl)chlorin (Temoporfin) with Serum Proteins: Protein Binding and Liposome Destruction

mTHPC is a non polar photosensitizer used in photodynamic therapy. To improve its solubility and pharmacokinetic properties, liposomes were proposed as drug carriers. Binding of liposomal mTHPC to serum proteins and stability of drug carriers in serum are of major importance for PDT efficacy; however, neither was reported before. We studied drug binding to human serum proteins using size‐exclusion chromatography. Liposomes destruction in human serum was measured by nanoparticle tracking analysis (NTA). Inclusion of mTHPC into conventional (Foslip^®) and PEGylated (Fospeg^®) liposomes does not affect equilibrium serum protein binding compared with solvent‐based mTHPC. At short incubation times the redistribution of mTHPC from Foslip^® and Fospeg^® proceeds by both drug release and liposomes destruction. At longer incubation times, the drug redistributes only by release. The release of mTHPC from PEGylated vesicles is delayed compared with conventional liposomes, alongside with greatly decreased liposomes destruction. Thus, for long‐circulation times the pharmacokinetic behavior of Fospeg^® could be influenced by a combination of protein‐ and liposome‐bound drug. The study highlights the modes of interaction of photosensitizer‐loaded nanovesicles in serum to predict optimal drug delivery and behavior in vivo in preclinical models, as well as the novel application of NTA to assess the destruction of liposomes.     

A cross-metathesis approach to the synthesis of new etretinate type retinoids, ethyl retinoate and its 9Z-isomer

Two aromatic retinoids were synthesized from styrene derivatives using a novel strategy with a cross-metathesis reaction as a key step. The biological activity of the new etretinate analogues was tested. Cross-metathesis reactions were also employed for the preparation of ethyl retinoate and its 9Z-isomer via the C₁₅ + C₅ route.     

α-Amidoalkylating agents from N-acyl-α-amino acids: 1-(N-acylamino)alkyltriphenylphosphonium salts

N-Acyl-α-amino acids were efficiently transformed in a two-step procedure into 1-N-(acylamino)alkyltriphenylphosphonium salts, new powerful α-amidoalkylating agents. The effect of the α-amino acid structure, the base used [MeONa or a silica gel-supported piperidine (SiO(2)-Pip)], and the main electrolysis parameters (current density, charge consumption) on the yield and selectivity of the electrochemical decarboxylative α-methoxylation of N-acyl-α-amino acids (Hofer-Moest reaction) was investigated. For most proteinogenic and all studied unproteinogenic α-amino acids, very good results were obtained using a substoichiometric amount of SiO(2)-Pip as the base. Only in the cases of N-acylated cysteine, methionine, and tryptophan, attempts to carry out the Hofer-Moest reaction in the applied conditions failed, probably because of the susceptibility of these α-amino acids to an electrochemical oxidation on the side chain. The methoxy group of N-(1-methoxyalkyl)amides was effectively displaced with the triphenylphosphonium group by dissolving an equimolar amount of N-(1-methoxyalkyl)amide and triphenylphosphonium tetrafluoroborate in CH(2)Cl(2) at room temperature for 30 min, followed by the precipitation of 1-N-(acylamino)alkyltriphenylphosphonium salt with Et(2)O.     

Amphiphilic meso(sulfonate ester fluoroaryl)porphyrins: refining the substituents of porphyrin derivatives for phototherapy and diagnostics

A set of amphiphilic fluorinated porphyrins appended with sulfonate ester groups were synthesized and fully characterized. The reaction proceeds efficiently, with high yields, with an improved methodology. Their potential use as imaging and phototherapeutic agents was assessed measuring relevant photophysical properties. It is shown that these porphyrins have good photostability, long triplet lifetimes (between 47 μs and 102 μs), high singlet oxygen quantum yields (0.74≤FD≤1.00), low fluorescence quantum yields (<0.04) and sharp 19F NMR peaks. The data on the new meso(sulfonate ester fluoroaryl)porphyrins illustrate the potential of perfluorinated sulfonate esters to improve physical properties relevant for cancer imaging and photodynamic therapy.     

Solid electrolyte interphase formation on metallic lithium

Solutions of three salts (LiBF₄, LiNTf₂, LiPF₆) in N-methyl-2-pyrrolidone (NMP), selected arbitrarily as a reference solvent, were investigated by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy techniques. The lithium surface in contact with LiPF₆ in NMP electrolyte was covered with a protective layer (SEI) which morphology comprise small particles (of ca. 0.2 μm in radius). This salt was selected for further studies. The impedance of the Li|(LiPF₆ in NMP?+?additive)|Li system was measured immediately after cell assembly and after galvanostatic charging/discharging. Fifteen different additives (10 wt.%) were used. The efficiency of individual additives was evaluated in terms of the Li|electrolyte system resistance (ΔR) or total cell impedance reduction, both deduced from EIS. Some of the additives were able to form the SEI layer and to reduce resistance/impedance of the Li|electrolyte interphase. In such cases, the lithium surface was covered with relatively uniform conglomerates, or regions separated by cracks, of ca. 1–2 μm in dimension.     

Hydrogenolysis goes bio: from carbohydrates and sugar alcohols to platform chemicals

In view of the diminishing oil resources and the ongoing climate change, the use of efficient and environmentally benign technologies for the utilization of renewable resources has become indispensible. Therein, hydrogenolysis reactions offer a promising possibility for future biorefinery concepts. These reactions result in the cleavage of C-C and C-O bonds by hydrogen and allow direct access to valuable platform chemicals already integrated in today's value chains. Thus, hydrogenolysis bears the potential to bridge currently available technologies and future biomass-based refinery concepts. This Review highlights past and present developments in this field, with special emphasis on the direct utilization of cellulosic feedstocks.