Investigation of inclusion complex of metformin into selective cyclic peptides as novel drug delivery system: Structure,electronic properties,AIM, and NBO study via DFT

In this study, the density functional theory computational method is used to investigate the encapsulation process of metformin into three types of the cyclic peptides composed of eight serine (CP1), eight glycine (CP2), and four serine‐glycine (CP3) cyclic peptides as a new model in the process of drug delivery in the gas phase. The obtained results using the B3LYP/6‐31++G (d,p) method indicate that the complexes formed are energetically favored. Furthermore, results reveal that the drug encapsulation process is typically chemisorption. The natural bonding orbital analysis shows that the intermolecular interaction of the C2 complex (metformin/CP2) is stronger than the C1 (Metformin/CP1) and C3 (Metformin/CP3) complexes due to greater total charge transfer energy, and the C1 complex is found to be the most favored complex. The theory of atoms in molecule (AIM) method is used to analyze the nature of interactions in different molecular systems. The results show the investigated cyclic peptides as effective carriers of metformin in the nanomedicine field.     

Some Applications of the Open Mapping Theorem in Locally Convex Cones

Ukrainian Mathematical Journal - We show that a continuous open linear operator preserves the completeness and barreledness in locally convex cones. Specially, we prove some relations between an...     

Regioselective and solvent-free arylation of β-nitrostyrenes with mono- and dialkyl anilines

Research on Chemical Intermediates - A green and solvent-free method were developed for alkylation of N,N-dialkylanilines with substituted β-nitrostyrenes using 10 mol% of choline...     

Thue’s inequalities and the hypergeometric method

We establish upper bounds for the number of primitive integer solutions to inequalities of the shape \(0<|F(x, y)| \le h\), where \(F(x , y) =(\alpha x + \beta y)^r -(\gamma x + \delta y)^r \in \mathbb {Z}[x ,y]\), \(\alpha \), \(\beta \), \(\gamma \) and \(\delta \) are algebraic constants with \(\alpha \delta -\beta \gamma \ne 0\), and \(r \ge 5\) and h are integers. As an important application, we pay special attention to binomial Thue’s inequalities \(|ax^r - by^r| \le c\). The proofs are based on the hypergeometric method of Thue and Siegel and its refinement by Evertse.     

Hydrophobic poly(lauryl methacrylate)‐coated magnetic nano‐composite particles for removal of organic pollutants

This paper described a simple novel technique to prepare magnetic nano‐composite particles coated with highly crosslinked poly(lauryl methacrylate) (PLMA), a hydrophobic polymer because of its long chain alkyl group for application in waste water purification. Nano‐sized magnetite (Fe₃O₄) particles prepared by coprecipitation of Fe²⁺ and Fe³⁺ from their alkali aqueous solution were encapsulated with SiO₂ following treatment with tetraethylorthosilicate (TEOS). Finally precipitation copolymerization of LMA and divinyl benzene (DVB) in the presence of Fe₃O₄/SiO₂ particles was carried out within stable isolated droplets containing hexadecane–toluene mixture (4:1 mixture HD‐T). The produced PLMA‐coated magnetic composite particles named as Fe₃O₄/SiO₂/P(LMA‐DVB) were characterized by Fourier Transform IR (FTIR), transmission electron microscopy (TEM), thermogravimetry (TG) and X‐ray diffractometer (XRD) analyses. The performance of the composite particles was evaluated for the removal of organic pollutants from water. Copyright © 2015 John Wiley & Sons, Ltd.     

Preliminary electrochemical studies of the flavohaemoprotein from Ralstonia eutropha entrapped in a film of methyl cellulose: Activation of the reduction of dioxygen

A flavohaemoprotein (FHP) from Ralstonia eutropha, obtained in a pure and active form, has been entrapped in a film of methyl cellulose on the electrode surface and gives a stable and reproducible electrochemical response at pH 7.00 when subject to cyclic voltammetry using a glassy carbon electrode. To our knowledge, no previous direct electrochemistry had been achieved with a bacterial flavohaemoglobin, which possess both a FAD and a haem. A single couple is observed which is assigned to the haem moiety of the protein, since the same result is obtained with a semi-apo form of the protein deprived of FAD (semi-apo FHP). The data collected were further confirmed by potentiometry with a platinum electrode, and the homogeneous electron transfer rate estimated by double potential step chronocoulometry at a bare glassy carbon electrode in the presence of methyl viologen (MV). The presence of FAD in the holoprotein is easily confirmed by UV-Vis spectrophotometry, but its expected electron relay role remains elusive. The protein activates the reduction of dioxygen by about 400 mV, the reduction current being proportional to the concentration of dioxygen up to 10% in volume in the gas mixture.     

Synthesis and Crystal Structure of CeIII and BiIII Complexes and Solution Studies of ZnII,CdII, PbII,CeIII, and BiIII Complexes Obtained from Proton Transfer Compounds Containing 2,6‐Pyridinedicarboxylate Ion

The two complexes (pydaH)₂[Ce(pydc)₂(H₂O)₂]₂ · 2H₂O (1) and (phenH)₂[Bi(pydc)₂(H₂O)]₂ · 5H₂O (2) were prepared from the proton transfer compounds containing the 2,6‐pyridinedicarboxylate ion. 1 was synthesized from the reaction of Ce(NO)₃ · 6H₂O with the proton transfer compound, (pydaH₂)(pydc), (pyda=2,6‐diaminopyridine, pydcH₂=2,6‐pyridinedicarboxylic acid). 2 was synthesized from the reaction of proton transfer compound, (phenH)₂(pydc), (phen=1,10‐phenanthroline), with Bi(NO₃)₃ · 5H₂O. The characterization was carried out using IR, ¹H and ¹³C NMR spectroscopy, elemental analysis and single crystal X‐ray diffraction. The complex 1 crystallizes in the space group of the triclinic system, and contains two molecules per unit cell. The structure has been refined to a final value for the crystallographic R factor of 0.0342 based on 8851 reflections. The unit cell parameters are: a = 9.753(2) Å, b = 10.503(2) Å, c = 10.774(2) Å, α = 83.905(4)°, β = 88.089(4)°, and γ = 82.636(3)°. The crystal structure illustrates that cerium atoms are connected together through the four‐membered ring Ce₂O₂. 2,6‐Pyridinedicarboxylate fragment acts as a tridentate ligand. The molecular structure contains four (pydc)^2? ligands, two of which are bridge ligands linking the two central atoms. The complex 2 crystallizes in the space group of the triclinic system and contains two molecules per unit cell. The unit cell dimensions are: a = 8.8860(4) Å, b = 12.0132(6) Å, c = 13.0766(6) Å, α = 100.967(1)°, β = 96.681(1)° and γ = 94.191(1)°. The structure has been refined to a final value for the crystallographic R factor of 0.0471 based on 9576 reflections. In this complex, 2,6‐pyridinedicarboxylate moiety has acted as a tridentate ligand and the lattice is composed of binuclear unit, [Bi(pydc)₂(H₂O)]₂^2?, (phenH)⁺ counter ions and five lattice waters. In both complexes hydrogen bonds, π‐π stacking and ion‐pairing play important roles in stabilizing the corresponding lattice. The stoichiometry and stability of the Zn^II, Cd^II, Pb^II, and Ce^III complexes with (pydaH₂)(pydc) in aqueous solution were investigated by potentiometric pH titration. The solution studies revealed that the stoichiometry of the crystalline complexes of the proton transfer system (pydaH₂)(pydc) with Ce^III, obtained in this study, and those with Zn^II, Cd^II and Pb^II, reported in our previous studies, are in close agreements. The complexation reactions of phen, pydc, and 2phen+pydc with Bi^III in aqueous solution were investigated by potentiometric pH titrations, and the equilibrium constants for all major complexes formed are described.     

Representations of the general linear group over symmetry classes of polynomials

Let V be the complex vector space of homogeneous linear polynomials in the variables x₁,..., x _m . Suppose G is a subgroup of S _m , and χ is an irreducible character of G. Let H _d (G, χ) be the symmetry class of polynomials of degree d with respect to G and χ.

For any linear operator T acting on V, there is a (unique) induced operator K _χ (T) ∈ End(H _d (G, χ)) acting on symmetrized decomposable polynomials by

$${K_\chi }\left( T \right)\left( {{f_1} * {f_2} * \cdots * {f_d}} \right) = T{f_1} * T{f_2} * \cdots * T{f_d}.$$

In this paper, we show that the representation T ? K _χ (T) of the general linear group GL(V) is equivalent to the direct sum of χ(1) copies of a representation (not necessarily irreducible) T ? B _χ ^G (T).

     

Time-gated luminescence microscopy with responsive nonmetal probes for mapping activity of protein kinases in living cells

A photoluminescence probe ARC-1185, possessing both high affinity towards basophilic protein kinases (PKs) and microsecond-scale luminescence lifetime when associated with a kinase, was used for the mapping of ARC-1185-PK complexes in living cells with time-gated luminescence microscopy.     

Qualitative and quantitative assessment of extracted oil from Camelina sativa seed treated by dielectric-barrier discharge cold plasma

This study aimed to investigate the effects of dielectric-barrier discharge (DBD) cold plasma (CP) pretreatment on Camelina sativa “Soheil cultivar” seed. A DBD plasma reactor system was employed for this purpose. The experiments were performed by taking into account variables including voltages of 15, 18, and 21 kV and times of 2, 4, 8, and 16 min. The measured properties were oil yield extraction (%), oil colour parameters (CIEL*a*b*), protein content (meal) (%), surface analysis using Scanning Electron Microscopy (SEM), and fatty acids profile of Camelina sativa. The results revealed that the CP treatment had a significant improvement in different properties of the extracted oil. It was observed that the extracted oil was increased, with the increasing time of CP exposure. The treatments of CP enhanced the oil yield from 24.3 to 31.5%, and the optimal conditions were identified as 21 kV and 16 min. Also, the maximum protein amount was observed for the samples treated by CP (39.5%). The SEM analysis showed that the cell structures of pre-treated Camelina samples were damaged, thereby improved the oil extraction efficiency. The variations in the values of L*, a*, and b* (max-min) were calculated to be 3.9, −2.5, and 9.7, respectively, which indicated minor changes of CP treatment on the oil colour parameters. The treated samples showed considerable changes of enhancement in linolenic and linoleic acids among poly-unsaturated fatty acids; and a reduction in palmitic acid content, among saturated fatty acids.