The effect of tethered polymers on the conformation of a lipid membrane

We consider the effect of tethered macromolecules on the stability of the flat conformation of a lipid bilayer in a dense brush regime when anchored chains are significantly overlapped. On the basis of a scaling approach we have shown that redistribution of polymer chains from inner to outer layers reduces the free energy of the system and stabilizes spherically bent configurations of the membrane.     

Proteomic Signature of Extracellular Vesicles for Lung Cancer Recognition

The proteins of extracellular vesicles (EVs) that originate from tumors reflect the producer cells’ proteomes and can be detected in biological fluids. Thus, EVs provide proteomic signatures that are of great interest for screening and predictive cancer diagnostics. By applying targeted mass spectrometry with stable isotope-labeled peptide standards, we assessed the levels of 28 EV-associated proteins, including the conventional exosome markers CD9, CD63, CD81, CD82, and HSPA8, in vesicles derived from the lung cancer cell lines NCI-H23 and A549. Furthermore, we evaluated the detectability of these proteins and their abundance in plasma samples from 34 lung cancer patients and 23 healthy volunteers. The abundance of TLN1, TUBA4A, HSPA8, ITGB3, TSG101, and PACSIN2 in the plasma of lung cancer patients was measured using targeted mass spectrometry and compared to that in plasma from healthy volunteers. The most diagnostically potent markers were TLN1 (AUC, 0.95), TUBA4A (AUC, 0.91), and HSPA8 (AUC, 0.88). The obtained EV proteomic signature allowed us to distinguish between the lung adenocarcinoma and squamous cell carcinoma histological types. The proteomic cargo of the extracellular vesicles represents a promising source of potential biomarkers.     

3,5‐Bis­[4‐(diethyl­amino)­benzyl­idene]‐1‐methyl‐4‐piperidone and 3,5‐bis[4‐(diethyl­amino)­cinnamyl­idene]‐1‐methyl‐4‐piperidone: prospective biophotonic materials

The structures of 3,5‐bis­[4‐(diethyl­amino)­benzyl­idene]‐1‐methyl‐4‐piperidone, C₂₈H₃₇N₃O, (I), and 3,5‐bis­[4‐(diethyl­amino)­cinnamyl­idene]‐1‐methyl‐4‐piperidone, C₃₂H₄₁N₃O, (II), have been characterized. Because of conjugation between donor and acceptor parts, the central heterocycles (including the carbonyl group) in (I) and (II) are flattened and exhibit a `sofa' conformation, with a deviation of the N atom from the planar fragment. The dihedral angles between the planar part of the heterocycle and the two almost flat fragments that include a phenyl ring and bridging atoms are 23.2 (1) and 11.2 (1)° in (I), and 11.8 (1) and 8.7 (2)° in (II). One‐ and two‐photon absorption of light and the fluorescence of (I) and (II) have also been characterized.     

Di­chloro­bis­(imidazolidin‐2‐one‐κO)­zinc(II) at 150 K

In the title compound, [ZnCl₂(C₃H₆N₂O)₂], the zinc(II) cation is surrounded by a distorted tetrahedral environment consisting of two Cl anions and two imidazolidin‐2‐one mol­ecules, the latter bound to the metal through their carbonyl O atoms. All atoms that are able to participate in hydrogen bonding are involved in such interactions. A hydrogen‐bonding network mediates the formation of mol­ecular columns parallel to the a axis. Neighboring columns are not bound by significant non‐covalent interactions; the result is an extended pattern of supramolecular aggregation that is intermediate in completeness between the situations observed in two related complexes of cobalt that have been studied previously.     

Unsymmetrical Trifluoromethyl Methoxyphenyl β-Diketones: Effect of the Position of Methoxy Group and Coordination at Cu(II) on Biological Activity

Copper(II) complexes with 1,1,1-trifluoro-4-(4-methoxyphenyl)butan-2,4-dione (HL1) were synthesized and characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The biological properties of HL1 and cis-[Cu(L1)₂(DMSO)] (3) were examined against Gram-positive and Gram-negative bacteria and opportunistic unicellular fungi. The cytotoxicity was estimated towards the HeLa and Vero cell lines. Complex 3 demonstrated antibacterial activity towards S. aureus comparable to that of streptomycin, lower antifungal activity than the ligand HL1 and moderate cytotoxicity. The bioactivity was compared with the activity of compounds of similar structures. The effect of changing the position of the methoxy group at the aromatic ring in the ligand moiety of the complexes on their antimicrobial and cytotoxic activity was explored. We propose that complex 3 has lower bioavailability and reduced bioactivity than expected due to strong intermolecular contacts. In addition, molecular docking studies provided theoretical information on the interactions of tested compounds with ribonucleotide reductase subunit R2, as well as the chaperones Hsp70 and Hsp90, which are important biomolecular targets for antitumor and antimicrobial drug search and design. The obtained results revealed that the complexes displayed enhanced affinity over organic ligands. Taken together, the copper(II) complexes with the trifluoromethyl methoxyphenyl-substituted β-diketones could be considered as promising anticancer agents with antibacterial properties.     

Substituted 1,3,2,4‐benzodithiadiazines: Novel derivatives,by‐products,and intermediates*

The synthesis of the title compounds 1 by 1 : 1 condensation of Ar NSNSiMe₃ 2 with SCl₂ followed by intramolecular ortho‐cyclization of each [Ar NSN S Cl] intermediate is complicated by further reaction of 1 with SCl₂ to give Herz salts 3 . With the 2 :SCl₂ ratio of 2:1, the formation of by‐products 3 is reduced and novel compounds 1 are accessible. With ortho‐I containing starting material 2j , the parent compound 1s is obtained as the result of an unexpected I, not H, substitution. The rate of the 1 + SCl₂ reaction depends upon a substituent's position, and the minor 8‐R isomers 1l,p (R = Br, I) are isolated for the first time from mixtures with the major 6‐R isomers due to reduced reactivity toward SCl₂. The synthesized compounds 1–3 are characterized by multinuclear (including nitrogen) NMR and X‐ray crystallography. According to the X‐ray diffraction data, 1j (6‐Br) and 1k (7‐Br) derivatives are planar, whereas 1i (5‐Br) and 1l (8‐Br) are bent along the S1···N4 line by ∼5° and ∼4°, respectively, and the 1r (7‐OCH₃) derivative is planar in contrast to the known 5‐OCH₃ isomer, which possesses a significantly folded heterocycle. The distortion of the planar geometry of some compounds 1 is interpreted in terms of a pseudo‐Jahn‐Teller effect as the result of π‐highest occupied molecular orbital (HOMO)  σ*‐(LUMO) lowest unoccupied molecular orbital + 1 mixing in a planar conformation. The 2p compound is the first structurally defined Ar–N = S = N–SiMe₃ azathiene. The compound Ar–N = S = N–S–NH‐Ar 6 modeling the aforementioned intermediate has been isolated and structurally characterized. We describe the attempts to synthesize compounds 1 from 2‐aminobenzenethiols and (SN)₄ and from salts 3 and Me₃SiN₃, and we discuss the reaction pathways. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:563–576, 2001     

1,3-Phosphorotropic rearrangement of pyridyl phosphates to hydroxypyridyl phosphonates

The lithium diisopropylamide (LDA) induced regioselective 1,3-rearrangement of 3- and 2- pyridyl phosphates into the corresponding 3-hydroxy-4-pyridyl-and 2-hydroxy-3-pyridylphosphonates has been observed and investigated. The rearrangement is proposed as a useful method for a directed introduction of a phosphoryl group into a hydroxypyridine nucleus.     

Optimal control of a two-body limbless crawler along a rough horizontal straight line

Nonlinear Dynamics - An optimal control problem is solved for a two-body limbless locomotor crawling along a straight line on a horizontal rough plane. Coulomb’s dry friction acts between the...