Antioxidant,Antibacterial and Dyeing Potential of Crude Pigment Extract of Gonatophragmium triuniae and Its Chemical Characterization

Filamentous fungi synthesize natural products as an ecological function. In this study, an interesting indigenous fungus producing orange pigment exogenously was investigated in detail as it possesses additional attributes along with colouring properties. An interesting fungus was isolated from a dicot plant, Maytenus rothiana. After a detailed study, the fungal isolate turned out to be a species of Gonatophragmium belonging to the family Acrospermaceae. Based on the morphological, cultural, and sequence-based phylogenetic analysis, the identity of this fungus was confirmed as Gonatophragmium triuniae. Although this fungus grows moderately, it produces good amounts of pigment on an agar medium. The fermented crude extract isolated from G. triuniae has shown antioxidant activity with an IC₅₀ value of 0.99 mg/mL and antibacterial activity against Gram-positive bacteria (with MIC of 3.91 μg/mL against Bacillus subtilis, and 15.6 μg/mL and 31.25 μg/mL for Staphylococcus aureus and Micrococcus luteus, respectively). Dyeing of cotton fabric mordanted with FeSO₄ using crude pigment was found to be satisfactory based on visual observation, suggesting its possible use in the textile industry. The orange pigment was purified from the crude extract by preparative HP-TLC. In addition, UV-Vis, FTIR, HRMS and NMR (¹H NMR, ¹³C NMR), COSY, and DEPT analyses revealed the orange pigment to be “1,2-dimethoxy-3H-phenoxazin-3-one” (C₁₄H₁₁NO₄, m/z 257). To our understanding, the present study is the first comprehensive report on Gonatophragmium triuniae as a potential pigment producer, reporting “1,2-dimethoxy-3H-phenoxazin-3-one” as the main pigment from the crude hexane extract. Moreover, this is the first study reporting antioxidant, antibacterial, and dyeing potential of crude extract of G. triuniae, suggesting possible potential applications of pigments and other bioactive secondary metabolites of the G. triuniae in textile and pharmaceutical industry.     

An optically-pumped multigas Far-IR laser

We report here the operation of an optically-pumped multigas Far-IR laser. In our experiment, three different gases (CH₃OH, CH₃Br, CH₃I) were simultaneously introduced into the Far-IR cavity. By adjusting the partial pressures of the gases and by tuning the appropriate CO₂ laser pump line, we were able to obtain the laser action for each one of them as efficiently as is observed when the gases are present by themselves.     

Polymerization of furil in the solid state by reaction with AsF5 at the solid–gas interface

Solid-state polymerization of furil, induced by reaction with AsF₅ at the solid–gas interface, has been investigated by means of vibrational analysis of the reactant and the product. Infrared spectra are consistent with the mode of Polymerization which involves an α,α′ linkage and subsequent loss of hydrogen atoms. The C/H elemental analysis suggests that the polymer consists of around six or seven monomeric units. The reaction product is found to be unstable at high temperatures; a prolonged annealing at this temperature leads to a different structure, possibly, by the opening of the furan rings. The x-ray powder diffraction study shows that the polymeric furil is crystalline, with a lattice similar to that of the monomer, but contains a considerable amount of disorder.     

Dramatic enhancement of third-harmonic generation in three-dimensional photonic crystals

We have observed a dramatic enhancement of third-harmonic generation in 3D polystyrene-air photonic crystals pumped by a near infrared laser beam. As the pump wavelength is tuned, the peak of the enhancement occurs when the third-harmonic wavelength approaches the short-wavelength edge of the band gap. We show that the origin of the enhancement is phase matching provided by the periodic structure of the photonic crystals.     

Two-photon excited intramolecular energy transfer and light-harvesting effect in novel dendritic systems

Two-photon absorption excited intramolecular energy transfer and light-harvesting effects are demonstrated in three novel dendritic systems. These systems contain both an antenna structure that can effectively absorb two-photon energy at approximately 800 nm and emit fluorescence at approximately 515 nm and a core moiety that can absorb one-photon energy at approximately 520 nm and emit at approximately 590 nm. Covalently combining the core and antenna functionalities intrinsically changes the optical behavior of the component pieces. The two-photon energy absorbed by the antenna structure is resonantly transferred to the core, where the core's emission intensity is enhanced by 8, 20, and 34 times for the three dendritic systems.     

Fully transitive -groups with finite first Ulm subgroup

An abelian -group is called (fully) transitive if for all with ( ) there exists an automorphism (endomorphism) of which maps onto . It is a long-standing problem of A. L. S. Corner whether there exist non-transitive but fully transitive -groups with finite first Ulm subgroup. In this paper we restrict ourselves to -groups of type , this is to say -groups satisfying . We show that the answer to Corner's question is no if is finite and is of type .

     

Preparation,spectral and structural characterization of (2-benzoylpyridine N(4)-methyl-N(4)-phenylthiosemicarbazonato) chloropalladium(II)

The synthesis, as well as spectral and structural characterization, of (2-benzoylpyridine-N(4)-methyl-N(4)-phenylthiosemicarbazonato)chloropalladium(II), [Pd(Bz4MePh)Cl], is described. The unit cell contains two crystallographically independent molecules [Pd(1)(Bz4MePh)Cl], (1), and [Pd(2)(Bz4MePh)Cl], (2), stabilized by intra- and intermolecular hydrogen bonding. The distance between the Pd(1) and Pd(2) centres is 3.5038(11) Å. The spectroscopic techniques used in this study are the following: u.v.-visible, i.r. and ¹H n.m.r. The protonation constants, determined spectrophotometrically, of the uncoordinated HBz4MePh are pK_a1 = 10.82 ± 0.03 and pK_a2 = 4.09 ± 0.02.     

Influence of non-reactive solvent on optical performance, photopolymerization kinetics and morphology of nanoporous polymer gratings

A study of nanoporous polymer gratings, with controllable nanostructured porosity, as a function of grating performance, photopolymerization kinetics and morphology is presented. Modifying the standard holographic polymer dispersed liquid crystal (H-PDLC) system, by including a non-reactive solvent, results in a layered, nanoporous morphology and produces reflective optical elements with excellent optical performance of broadband reflection. The addition of the non-reactive solvent in the pre-polymer mixture results in a morphology typified by void/polymer layer-by-layer structures if sufficient optical energy is used during the holographic writing process. The duration and intensity of optical exposure necessary to form well-aligned nanoporous structures can only be obtained in the modified system by (a) illumination under longer time of holographic interference patterning (30 min) or (b) illumination under very short time of holographic interference patterning (30 s) and followed by post-curing using homogeneous optical exposure for 60 min. Comparatively, a typical H-PDLC is formed in less than 1 min. To further understand the differences in the formation of these two analogous materials, the temporal dynamics of the photoinitiation and polymerization (propagation) kinetics were examined. It is shown herein that the writing exposure gives a cross-linked polymer network that is denser in the bright regions. With 60% (or even 45%) acrylate conversion, almost no free monomer would be left after the writing. Continued exposure serves primarily to add cross-links. This has the tendency to collapse the network, especially the less dense portions, which in effect get glued down to the more dense parts. To the extent that the solvent increases the mobility of the polymer network, this process will be aided. Equally important, the size of the periodic nanopores can be varied from 10 to 50 nm by controlling either the LC concentration in the pre-polymer mixture or by controlling the time of the homogeneous post-cure.     

Superior optical limiting, stabilization, and spatio-temporal reshaping of ultrashort laser pulses in an opto-stable intrinsic polymer film

A chemically modified poly(fluorene-alt-benzothiadiazole) (PFBT) polymer film is reported to exhibit high two-photon absorbing capability and chemical/physical stability upon the action of high-power laser pulses of ~780 nm wavelength and ~160 fs duration. A nonlinear transmission measurement is conducted by varying the input intensity from ~20 to ~600 GW/cm2, the corresponding nonlinear transmission of a ~70 μm thick film is reduced from ~0.8 to 0.18, indicating a superior optical limiting behavior. In the meantime, intensity fluctuation of laser pulses can be significantly reduced after passing through the same film sample. Based on the intensity-dependent nonlinear attenuation mechanism, a straightforward optical reshaping effect on spatio-temporal profiles of the laser pulses has also been demonstrated.