Polymeric Encapsulation of Novel Homoleptic Bis(dipyrrinato) Zinc(II) Complexes with Long Lifetimes for Applications as Photodynamic Therapy Photosensitisers

The use of photodynamic therapy (PDT) to treat cancer has received increasing attention over the last years. However, the clinically used photosensitisers (PSs) have some limitations that include poor aqueous solubility, hepatotoxicity, photobleaching, aggregation, and slow clearance from the body, so the design of new classes of PSs is of great interest. We present the use of bis(dipyrrinato)zinc(II) complexes with exceptionally long lifetimes as efficient PDT PSs. Based on the heavy‐atom effect, intersystem crossing of these complexes changes the excited state from singlet to a triplet state, thereby enabling singlet oxygen generation. To overcome the limitation of quenching effects in water and improve water solubility, the lead compound 3 was encapsulated in a polymer matrix. It showed impressive phototoxicity upon irradiation at 500 nm in various monolayer cancer cells as well as 3D multicellular tumour spheroids, without observed dark toxicity.     

Surface analysis of thermally annealed porous silicon

Quasi-monocrystalline porous silicon (QMPS) has high potential for photovoltaic application for its enhanced optical absorption compared to bulk silicon in the visible range of solar spectrum. In this study, QMPS was formed from low porosity (∼20-30%) porous silicon (PS) produced by electrochemical anodization, and thermal annealing in the temperature range 1050-1100 °C under pure hydrogen ambient for a duration of 30 min. We analyzed the material surface by grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and dynamic secondary ion mass spectroscopy (SIMS) study. The crystallinity was confirmed by GIXRD while FESEM studies revealed that the surface layer is pore free with voids embedded inside the body. AFM studies indicated relatively smooth and uniform surface and the dynamic SIMS study showed the depth profiles of impurities present in the material.     

The dynamical mixing of light and pseudoscalar fields

We solve the general problem of mixing of electromagnetic and scalar or pseudoscalar fields coupled by axion-type interactions L _int = g _ϕ ϕε _μναβ F ^μν F ^αβ . The problem depends on several dimensionful scales, including the magnitude and direction of background magnetic field, the pseudoscalar mass, plasma frequency, propagation frequency, wave number, and finally the pseudoscalar coupling. We apply the results to the first consistent calculations of the mixing of light propagating in a background magnetic field of varying directions, which show a great variety of fascinating resonant and polarization effects.      

On atomic analogue of Landau quantization

We have studied the physics of atoms with permanent electric dipole moment and nonvanishing magnetic moment interacting with an electric field and inhomogeneous magnetic field. This system can be demonstrated as the atomic analogue of Landau quantization of charged particles in a uniform magnetic field. This Landau-like atomic problem is also studied with space-space noncommutative coordinates.     

Development of a new catalytic and sustainable methodology for the synthesis of benzodiazepine triazole scaffold using magnetically separable CuFe2O4@MIL-101(Cr) nano-catalyst in aqueous medium

Magnetically retrieval CuFe₂O₄@MIL-101(Cr) metal–organic framework was successfully prepared from easily available starting materials and characterized using various spectroscopic and analytical techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray, transmission electron microscopy, elemental mapping, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller, vibrating sample magnetometer, and inductively coupled plasma optical emission spectroscopy. The catalyst was then used in the synthesis of benzodiazepines containing a triazole moiety in water. The advantages of this protocol include high yields, reusability of the catalyst, and gram-scale synthesis.     

Formulation and characterization of a biocompatible microemulsion composed of mixed surfactants: lecithin and Triton X-100

We report on the formation and characterization of a biocompatible microemulsion (ME) system composed of lecithin (L), Triton X-100 (T) as the surfactant(s), butyl lactate (BL) as the cosurfactant, and isopropyl myristate (IPM) as the oil phase and water. Detailed phase construction reveals that mixing of surfactants (L and T) produces larger single-phase ME region compared to L. In the mixed surfactant systems, a three-phase body appears which is otherwise not obtained in the single surfactant counterparts signifying the synergistic solubilization behaviour upon mixing. The maximum solubilization capacity decreases as the content of T increases in the mixture. Viscosity, conductance and adiabatic compressibility measurements of the single-phase ME systems at a constant amphiphile concentration (80 % w/w) show a linear trend with increasing water content revealing a droplet-type structure of all the studied formulations. FTIR studies in the water-in-oil (w/o) region identify the presence of three distinct types of water molecules in these systems and their relative content changes with the interfacial composition as well as the total water content in the system. Our study offers a biocompatible mixed ME system in which the physical properties do not differ much from those of the lecithin-based systems with the additional advantage of having higher solubilization capacity, low pH dependency and low viscosity, which renders its potential to be used for specific pharmaceutical applications.     

Reduced graphene oxide supported copper oxide nanocomposites: An efficient heterogeneous and reusable catalyst for the synthesis of ynones, 1,3-diynes and 1,5-benzodiazepines in one-pot under sustainable reaction conditions

A greener and efficient method for the synthesis of ynones and 1,3-diynes using copper oxide nanoparticles (CuONPs) doped reduced graphene oxide (CuO@rGO) catalyst under palladium, ligand and solvent free conditions have been developed. The catalyst was subsequently utilized for the synthesis of biologically active 1,5-benzodiazepines in one pot via sequential addition of acyl chlorides, terminal alkynes and o-phenylenediamines. The methodology initially involves in situ formation of ynones which react with o-phenylenediamines in presence of ethanol to afford a wide variety of benzodiazepines. Mild reaction conditions, good to an excellent yield of the products, cheap and recyclable catalyst make this methodology environmentally benign and sustainable.     

Graphene oxide (GO) catalyzed transamidation of aliphatic amides: An efficient metal-free procedure

Transamidation involves direct interconversion of an amide with amine, and represents an alternative to the common method of amide formation from the reaction of carboxylic acid with an amine. While the carboxamides have huge potential in biological systems and polymer industries, their formation from carboxylic acids requires activation by a suitable catalyst. A metal-free transamidation of aliphatic amide with aromatic amine catalyzed by graphene oxide (GO) has been developed and established as a general, synthetically useful and selective procedure. Graphene oxide bearing several carboxylic acids on the edges and having large surface area acts as an efficient and recyclable catalyst for transamidation.     

On the Number of Topological Types Occurring in a Parameterized Family of Arrangements

Let be an o-minimal structure over ℝ, a closed definable set, and

Temperature-dependent solvation dynamics of water in sodium bis(2-ethylhexyl)sulfosuccinate/isooctane reverse micelles

In this paper, for the first time, we report a detailed study of the temperature-dependent solvation dynamics of a probe fluorophore, coumarin-500, in AOT/isooctane reverse micelles (RMs) with varying degrees of hydration (w0) of 5, 10, and 20 at four different temperatures, 293, 313, 328, and 343 K. The average solvation time constant becomes faster with the increase in w0 values at a particular temperature. The solvation dynamics of a RM with a fixed w0 value also becomes faster with the increase in temperature. The observed temperature-induced faster solvation dynamics is associated with a transition of bound- to free-type water molecules, and the corresponding activation energy value for the w0 = 5 system has been found to be 3.4 kcal mol-1, whereas for the latter two systems, it is approximately 5 kcal mol-1. Dynamic light scattering measurements indicate an insignificant change in size with temperature for RMs with w0 = 5 and 10, whereas for a w0 = 20 system, the hydrodynamic diameter increases with temperature. Time-resolved fluorescence anisotropy studies reveal a decrease in the rotational restriction on the probe with increasing temperature for all systems. Wobbling-in-cone analysis of the anisotropy data also supports this finding.