20 research outputs found
Combined effect of Fe2+ ions and the meta-isomer of dihydric phenol on duckweed
The toxic effects of Fe2+ ions and resorcinol on Lemna minor in their joint presence in the aquatic environment were studied. The test response in the bioassay of solutions of Fe2+, resorcinol, and their mixtures was a violation of the permeability of duckweed membranes. This parameter was estimated from the change in the electrical conductivity of the aquatic medium in which the plant was placed, exposed to the toxicant in the acute experiment (30 min). It was found that the addition of both an equinormal concentration of Fe(II) (0.1n) and a five-fold deficiency (0.02n) to a 0.1n solution of resorcinol reduced the toxicity of resorcinol. Most likely, the effect obtained can be achieved by the formation of a new, less toxic compound (probably of a complex nature). The test used in the work, based on the assessment of the permeability of cell membranes under the action of toxicants, once again proved to be a promising tool for analyzing the combined toxicity of phenolic compounds and metal ions in relation to plant organisms
Combined effect of Fe
The toxic effects of Fe2+ ions and resorcinol on Lemna minor in their joint presence in the aquatic environment were studied. The test response in the bioassay of solutions of Fe2+, resorcinol, and their mixtures was a violation of the permeability of duckweed membranes. This parameter was estimated from the change in the electrical conductivity of the aquatic medium in which the plant was placed, exposed to the toxicant in the acute experiment (30 min). It was found that the addition of both an equinormal concentration of Fe(II) (0.1n) and a five-fold deficiency (0.02n) to a 0.1n solution of resorcinol reduced the toxicity of resorcinol. Most likely, the effect obtained can be achieved by the formation of a new, less toxic compound (probably of a complex nature). The test used in the work, based on the assessment of the permeability of cell membranes under the action of toxicants, once again proved to be a promising tool for analyzing the combined toxicity of phenolic compounds and metal ions in relation to plant organisms
A tectonogeodynamic model for the junction zone between the Fennoscandian and Sarmatian segments of the East European Platform
Bifurcate Hydrogen Bonds. Interaction of Intramolecularly H-Bonded Systems with Lewis Bases
Preoperative AI-Driven Fluorescence Diagnosis of Non-Melanoma Skin Cancer
The diagnosis and treatment of non-melanoma skin cancer remain urgent problems. Histological examination of biopsy material—the gold standard of diagnosis—is an invasive procedure that requires a certain amount of time to perform. The ability to detect abnormal cells using fluorescence spectroscopy (FS) has been shown in many studies. This technique is rapidly expanding due to its safety, relative cost-effectiveness, and efficiency. However, skin lesion FS-based diagnosis is challenging due to a number of single overlapping spectra emitted by fluorescent molecules, making it difficult to distinguish changes in the overall spectrum and the molecular basis for it. We applied deep learning (DL) algorithms to quantitatively assess the ability of FS to differentiate between pathologies and normal skin. A total of 137 patients with various forms of primary and recurrent basal cell carcinoma (BCC) were observed by a multispectral laser-based device with a built-in neural network (NN) “DSL-1”. We measured the fluorescence spectra of suspected non-melanoma skin cancers and compared them with “normal” skin spectra. These spectra were input into DL algorithms to determine whether the skin is normal, pigmented normal, benign, or BCC. The preoperative differential AI-driven fluorescence diagnosis method correctly predicted the BCC lesions. We obtained an average sensitivity of 62% and average specificity of 83% in our experiments. Thus, the presented “DSL-1” diagnostic device can be a viable tool for the real-time diagnosis and guidance of non-melanoma skin cancer resection
Apicophilicity versus Hydrogen Bonding. Intramolecular Coordination and Hydrogen Bonds in <i>N</i>‑[(Hydroxydimethylsilyl)methyl]-<i><i>N,N</i></i>′‑propyleneurea and Its Hydrochloride. DFT and FT-IR Study and QTAIM and NBO Analysis
Conformers
of <i>N</i>-[(hydroxydimethylsilyl)methyl]-<i><i>N,N</i></i>′-propyleneurea (<b>1</b>) and
their hydrochlorides (<b>2</b>) with HCl coordinated
to different basic sites have been studied experimentally by FT-IR
and theoretically using the density functional theory (DFT) method
at the B3LYP/6-311+G(d,p) and M06/6-311+G(d,p) levels of theory. The
structures of silanols <b>1</b> and <b>2</b> are determined
by the balance of two competing effects: namely, intramolecular CO→Si
coordination and intramolecular CO···H–O
or intermolecular X···H–Cl hydrogen bonding.
The preferred conformation of silanol <b>1</b> is that with
an equatorial hydroxyl group, in apparent contradiction with the apicophilicity
rule. In the crystal, silanol <b>1</b> exists as a conformer
with a bifurcated bond composed of a weak CO→Si coordinated
bond and a substantially more strong CO···H–O
hydrogen bond. From the NBO analysis, the energies of the n<sub>O</sub> → σ*<sub>Si–X</sub> and n<sub>O</sub> →
σ*<sub>H–O</sub> orbital interactions responsible for
the formation of the coordination and hydrogen bonds, as well as the
lengths of these bonds, change in opposite directions. In solution
the equilibrium is shifted toward the conformer having only the hydrogen
bond and no coordination bond. Its hydrochloride <b>2</b> exists
in the crystal as a conformer with the axial OH group coordinated
to HCl, whereas in solution it appears to be in equilibrium with a
conformer having the equatorial OH group, in which a four-centered
bifurcated bond is formed by two intramolecular components CO→Si
and CO···HO and one intermolecular component
CO···HCl. The QTAIM analysis showed the O→Si
coordination bonds in the studied compounds to fall in the range from
partially covalent and weak donor–acceptor to mainly electrostatic
in nature and the hydrogen bonds to vary from weak to medium in energy
Apicophilicity versus Hydrogen Bonding. Intramolecular Coordination and Hydrogen Bonds in <i>N</i>‑[(Hydroxydimethylsilyl)methyl]-<i><i>N,N</i></i>′‑propyleneurea and Its Hydrochloride. DFT and FT-IR Study and QTAIM and NBO Analysis
Conformers
of <i>N</i>-[(hydroxydimethylsilyl)methyl]-<i><i>N,N</i></i>′-propyleneurea (<b>1</b>) and
their hydrochlorides (<b>2</b>) with HCl coordinated
to different basic sites have been studied experimentally by FT-IR
and theoretically using the density functional theory (DFT) method
at the B3LYP/6-311+G(d,p) and M06/6-311+G(d,p) levels of theory. The
structures of silanols <b>1</b> and <b>2</b> are determined
by the balance of two competing effects: namely, intramolecular CO→Si
coordination and intramolecular CO···H–O
or intermolecular X···H–Cl hydrogen bonding.
The preferred conformation of silanol <b>1</b> is that with
an equatorial hydroxyl group, in apparent contradiction with the apicophilicity
rule. In the crystal, silanol <b>1</b> exists as a conformer
with a bifurcated bond composed of a weak CO→Si coordinated
bond and a substantially more strong CO···H–O
hydrogen bond. From the NBO analysis, the energies of the n<sub>O</sub> → σ*<sub>Si–X</sub> and n<sub>O</sub> →
σ*<sub>H–O</sub> orbital interactions responsible for
the formation of the coordination and hydrogen bonds, as well as the
lengths of these bonds, change in opposite directions. In solution
the equilibrium is shifted toward the conformer having only the hydrogen
bond and no coordination bond. Its hydrochloride <b>2</b> exists
in the crystal as a conformer with the axial OH group coordinated
to HCl, whereas in solution it appears to be in equilibrium with a
conformer having the equatorial OH group, in which a four-centered
bifurcated bond is formed by two intramolecular components CO→Si
and CO···HO and one intermolecular component
CO···HCl. The QTAIM analysis showed the O→Si
coordination bonds in the studied compounds to fall in the range from
partially covalent and weak donor–acceptor to mainly electrostatic
in nature and the hydrogen bonds to vary from weak to medium in energy