Size,Shape, and Wavelength Effect on Photothermal Heat Elevation of Gold Nanoparticles: Absorption Coefficient Experimental Measurement

Complex-shaped nanoparticles as gold nanourchins (GNU) and nanorods (GNR) are very suitable agents in the case of photothermal therapy due to their photon-heat conversion ability in the red and near-infrared region (NIR). The quantification in heat generation of complex shaped nanostructures is an important key to predict the therapeutic effect of these nanoparticles. For that, the determination of the nanoparticles absorption cross section (σ_Abs) responsible for the heat generation is one of the important steps before any application. Although it is obvious to determine σ_Abs for spheres via Mie's theory, in the case of complex structures like GNU or GNR, this parameter is difficult to model. In this work, a new methodology is used to determine experimentally σ_Abs for both GNU and GNR. Experimental measurements of the photothermal properties of 100 nm size GNU and two different sizes of GNRs are studied regarding different parameters such as concentration, laser excitation wavelength, and exposure time. By using the heat transfer theory, the temperature elevation in the nanoparticles solutions is converted to temperature elevation at the nanoparticles surface and σ_Abs values are then calculated for both GNU and GNR in the NIR spectral region.     

Synthesis of 1,6-didecylnaphtho[1,2-b:5,6-b']difuran-based copolymers by direct heteroarylation polymerization

The use of direct C H arylation cross-coupling polymerization was evaluated for the synthesis of donor–acceptor conjugated co-polymers using the novel donor 1,6-didecylnaphtho[1,2-b:5,6-b']difuran and either thieno[3,4-c]pyrrole-4,6-dione (TPD) or 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) as the acceptor. Thiophene and furan moieties were used to flank the DPP group and the impact of these heterocycles on the polymers' properties was evaluated. The alkyl chains on the diketopyrrolopyrrole monomers were varied to engineer the solubility and morphology of the materials. All of the polymers have similar optoelectronic properties with narrow optical band gaps around 1.3 eV, which is ideal for solar energy harvesting. Unfortunately, these polymers also had high-lying highest occupied molecular orbital levels of −4.8 to −5.1, and as a result bulk-heterojunction photovoltaic cells fabricated using the soluble fullerene derivative PC₇₁BM as the electron-acceptor and these polymers as donor materials exhibited poor performance due to limited V_oc values. An examination of the films from these blends indicates that film-thickness and morphology were also a major hindrance to performance and a potential point of improvement for future materials.     

In silico drug design and molecular docking of novel amidophosphonates and sulfamidophosphonates as inhibitors of urokinase-type plasminogen activator

Cancer is one of the most serious health problems worldwide, affecting individuals from different sexes, ages, and races. However, the most frequent cancer types in the world are lung, prostate, stomach, colorectal, and esophagus in men; and breast, lung, stomach, colorectal and cervical in women. Currently, the search for new active substances used in oral targeted therapies are legitimate and opens up the possibility of an "ambulatory shift" in cancer treatment. In order to design anti-tumor drug candidates endowed with oral bioavailability, we studied trough an in silico approach the oral bioavailability of newly synthesized biomolecules; α-sulfamidophosphonates and α-amidophosphonates as well as their mechanism of action on the new target urokinase-type plasminogen activator (uPA). The studied compounds have been found to meet the five criteria of. Lipinski's rule. The Osiris, Molinspiration and SWISS/ADME calculations related to the compounds (1d, 2a) have shown that these compounds could be good candidates for interacting with the different targets, they have convincing characteristics in relation to the standard drug used. It can be concluded that these compounds are biologically important and possessing molecular properties desirable for being a drug candidate for oral use.The molecular docking results of the studied compounds revealed a good ligand-target interactions, the compounds (1d, 2a) presented a possibility of interacting as an inhibitor of the anticancer target: urokinase-type plasminogen activator (uPA).     

Clay‐Na as a sorbent for the extraction of anti‐inflammatory compounds in water samples

In this work, clay‐Na particles are used as the adsorbent for the solid‐phase extraction of acidic compounds. The novel sorbent under study is based on high‐specific surface area, cation‐exchange capacity designed specifically to offer ion‐exchange properties with the goal being to selectively extract a group of acidic compounds. The effects of the extraction parameters including extraction elution solvent, sample volume and pH. In optimum conditions, the repeatability for one fiber (n = 3), expressed as % relative standard deviation, was between 0.3 and 4.3% for the acid compounds. The detection limits for the studied acidic compounds were between 0.1–0.6 μg/L. The developed method offers the advantages of being simple to use and having a low cost of equipment.     

A ring-closing metathesis approach to secosteroidal macrocycles

An efficient synthesis of secosteroidal macrocycles has been achieved via an oxidative ring-expansion/ring-opening sequence and a ring-closing metathesis reaction as the key steps.     

Considération sur l'ordre des acidités successives du diacide 7-para carboxy anilino 4-nitrobenzofurazane

On the dissociation constants of successive acidities of the diacid 7-para carboxy anilino-4-nitrobenzofurazane. The first dissociation constant of the 7-para carboxy anilino-4-nitrobenzofurazane noted 4H,COOH, in dimethylsulfoxyde was estimated using an NMR method. Diacid 4H,COOH was prepared by simple reaction of aromatic nucleophilic substitution (S_NAr) and monopotassium salt and was precipitated by chloroform addition to a solution of 4H,COOH in Me₂SO, after neutralisation of an acid function by one equivalent of solid potassium bicarbonate. Initially, a titration NMR ¹H of two acidities of 4H,COOH was carried out in Me₂SO-d₆ by the strong base potassium tert-butoxide. After, we showed that ionization NH/N⁻ is carried out completely before that of function COOH. We could estimate the first dissociation constant (7.5) of 4H,COOH in dimethylsulfoxyde by using the 9-cyano fluorene as a reference compound.     

Luminescent properties of Yb-doped monoclinic yttrium polyphosphates

Yb³⁺-doped monoclinic yttrium polyphosphate Y(PO₃)₃ powder compounds were synthesized and were characterized by X-ray diffraction, IR absorption spectroscopy and Raman scattering spectroscopy.An attempt to use Yb³⁺ ion as structural probe is carried out to investigate the site occupation. Yb³⁺ emission and fluorescence decay studies were carried out both at low and room temperatures. The interpretation of electronic energy level positions has been done by using the comparison of emission spectra with those of vibronic sideband energy positions from Raman scattering spectroscopy.The spectroscopic results are discussed and correlated with the data of the already known monoclinic structure of Y(PO₃)₃ where four slightly different octahedral sites are available for the trivalent rare earth ion.     

Optical and Calorimetrical Studies of Liquid Crystalline Materials Doped with Nanoparticles

Summary: Electro-optical properties of Polymer Dispersed Liquid Crystal (PDLC) films doped with different nanoparticles (NPs), as well as optical and morphological properties of liquid crystal/NP mixtures have been investigated. PDLC films were prepared by UV irradiation of thiol-ene monomers and liquid crystal E7 in the presence of a small amount (0.5 and 1 wt.%) of nanoparticles. The presence of NP strongly influence the properties of liquid crystal/NP mixtures. In particular, adding nanoparticles results in a decrease of the glass and nematic-isotropic transition temperatures of the LC, suggesting that strong interactions occur between LC and nanoparticles.     

ACr(C2O4)2(H2O)4 (A = Li or Na): two new coordination polymers of low dimensionality with different hydrogen‐bond networks

Single crystals of two new bimetallic oxalate compounds with the formula [ACr(C₂O₄)₂(H₂O)₄]_n (A = Li or Na), namely catena‐poly[[diaqualithium(I)]‐μ‐oxalato‐κ⁴O¹,O²:O^1′,O^2′‐[diaquachromium(III)]‐μ‐oxalato‐κ⁴O¹,O²:O^1′,O^2′], ( I ), and catena‐poly[[diaquasodium(I)]‐μ‐oxalato‐κ⁴O¹,O²:O^1′,O^2′‐[di‐aquachromium(III)]‐μ‐oxalato‐κ⁴O¹,O²:O^1′,O^2′], ( II ), have been synthesized, characterized and their crystal structures elucidated by X‐ray diffraction analysis and compared. The compounds crystallize in the monoclinic space group C2/m for ( I ) and in the triclinic space group P for ( II ); however, they have somewhat similar features. In the asymmetric unit of ( I ), the Li and Cr atoms both have space‐group‐imposed 2/m site symmetry, while only half of the oxalate ligand is present and two independent water molecules lie on the mirror plane. The water O atoms around the Li atom are disordered over two equivalent positions separated by 0.54 (4) Å. In the asymmetric unit of ( II ), the atoms of one C₂O₄^2? ligand and two independent water molecules are in general positions, and the Na and Cr atoms lie on an inversion centre. Taking into account the symmetry sites of both metallic elements, the unit cells may be described as pseudo‐face‐centred monoclinic for ( I ) and as pseudo‐centred triclinic for ( II ). Both crystal structures are comprised of one‐dimensional chains of alternating trans‐Cr(CO)₄(H₂O)₂ and trans‐A(CO)₄(H₂O)₂ units μ₂‐bridged by bis‐chelating oxalate ligands. The resulting linear chains are parallel to the [101] direction for ( I ) and to the [11] direction for ( II ). Within the two coordination polymers, strong hydrogen bonds result in tetrameric R₄⁴(12) synthons which link the metal chains, thus leading to two‐dimensaional supramolecular architectures. The two structures differ from each other with respect to the symmetry relations inside the ligand, the role of electrostatic forces in the crystal structure and the molecular interactions of the hydrogen‐bonded networks. Moreover, they exhibit the same UV–Vis pattern typical of a Cr^III centrosymmetric geometry, while the IR absorption shows some differences due to the oxalate‐ligand conformation. Polymers ( I ) and ( II ) are also distinguished by a different behaviours during the decomposition process, the precursor ( I ) leading to the oxide LiCrO₂, while the residues of ( II ) consist of a mixture of sodium carbonate and Cr^III oxide.