Miscibility of Two Components in a Binary Mixture of 9-Phenyl Anthracene Mixed with Stearic Acid or Polymethyl Methacrylate at Air-Water Interface

We report the miscibility characteristics of two components in a binary mixture of 9-phenyl anthracene （PA） mixed with stearic acid （SA） or polymethyl methacrylate （PMMA）. The behaviour of surface pressure versus area per molecule isotherms reveal that the area per molecule decreases systematically with increasing molefractions of PA. The characteristics of areas per molecule versus molefractions and collapse pressure vs molefraction indicate that various interactions involved among the sample and matrix molecules. The interaction scheme is found to change with the change in surface pressure and molefraction of mixing. Scanning electron microscopic study confirms the aggregation of PA molecules in the mixed films.     

Novasomes as Nano-Vesicular Carriers to Enhance Topical Delivery of Fluconazole: A New Approach to Treat Fungal Infections

The occurrence of fungal infections has increased over the past two decades. It is observed that superficial fungal infections are treated by conventional dosage forms, which are incapable of treating deep infections due to the barrier activity possessed by the stratum corneum of the skin. This is why the need for a topical preparation with advanced penetration techniques has arisen. This research aimed to encapsulate fluconazole (FLZ) in a novasome in order to improve the topical delivery. The novasomes were prepared using the ethanol injection technique and characterized for percent entrapment efficiency (EE), particle size (PS), zeta potential (ZP), drug release, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and antifungal activity. The FN7 formulation with 94.45% EE, 110 nm PS and −24 ZP proved to be the best formulation. The FN7 formulation showed a 96% release of FLZ in 8 h. FTIR showed the compatibility of FLZ with excipients and DSC studies confirmed the thermal stability of FLZ in the developed formulation. The FN7 formulation showed superior inhibition of the growth of Candida albicans compared to the FLZ suspension using a resazurin reduction assay, suggesting high efficacy in inhibiting fungal growth.     

Numerical study on optical and electrical properties of strained GaInSb/GaInAlSb mid-infrared quantum well laser

The optical and electrical properties of compressively strained GaInSb/GaInAlSb mid-infrared quantum well lasers are numerically studied solving one-dimensional Schrödinger equation using finite difference method. The simulation results demonstrate that band-mixing effects and effective mass of hole are reduced when the well is compressively strained. The strain-dependent optical and differential gains are evaluated for 0.6, 0.9, 1.21, and 1.52% compressively strained quantum well and found maximum when well is strained by 1.52%. The emission wavelength for the proposed laser can be tuned from 2.40 to 2.26 μm due to change in compressive strain from 0.60 to 1.52% at temperature 300 K. For the range of strain, the shift in wavelength is found from 2.38 to 2.24 μm at temperature 275 K. The results obtained from PSPICE simulation indicate that, the optical output power and threshold current are strongly depend on the number of wells and found to be almost constant for the number of wells three and above.     

New superconducting RbFe2As2: A first-principles investigation

RbFe₂As₂ has recently been reported to be a bulk superconductor with T_c = 2.6 K in the undoped state, in contrast to undoped BaFe₂As₂ with a magnetic ground state. We present here the results of the first-principles calculations of the structural, elastic and electronic properties for this newest superconductor and discuss its behaviour in relation to other related systems.     

Two Photon Spectroscopy Can Serve as a Marker of Protein Denaturation Pathway

Rhodamine group of molecules are widely used dyes for imaging of biological molecules. Application of these dyes however includes a limitation that these molecules absorb in the visible range of the spectrum, which does not fall in the ‘biologically transparent window’ (BTW). Two photon absorption (TPA) process could come up with an alternate solution to this as these dyes could be excited in the near infrared (NIR) window to extract similar information. To validate this we have investigated TPA cross section (TPACS, σ₂) of two rhodamine dyes, namely Rhodamine 6G (R6G), Rhodamine B (RhB), site selectively bound with a model protein, bovine serum albumin (BSA), by exciting at 800 nm. Two photon spectroscopy and imaging confirms the binding of the dye to the protein. The decreases in TPACS with increasing temperature at a fixed BSA concentration excellently follows the temperature induced structural transition of BSA as the protein transforms from a molten globule to unfolded conformation beyond 60 °C, which has previously been established through circular dichroism (CD) measurements. The thus established resemblance in TPACS and CD measurement trends thus strongly affirms the suitability of TPA process in protein imaging and as an alternative marker to tracking its conformational transformations using NIR radiation.     

Banchromene and other secondary metabolites from the endophytic fungus Fusarium sp. obtained from Piper guineense inhibit the motility of phytopathogenic Plasmopara viticola zoospores

A new chromene, (S)-banchromene (1), together with seven known compounds, ergosterol, beauvericin (2), fusaproliferin (3), radicinin (4), poly(3-hydroxybutyric acid) (PHB, 5), N-methylpyrrolidone and an inseparable mixture of isochromene derivatives 6a, 6b, were isolated from a culture of Fusarium sp. strain CAMKT24b1, an endophytic fungus from the leaves and twigs of Piper guineense (Piperaceae). The structures of these metabolites were elucidated on the basis of their spectroscopic data; the absolute configuration of 1 was determined by ab initio-calculation of the optical rotation. In tests with the zoospores of the grapevine downy mildew pathogen Plasmopara viticola, compounds 1–4 showed moderate to high levels of motility-impairing activity at concentrations as low as 2.5 μg/mL. Compound 2 was the most active, exhibiting both motility-halting and lytic activities. Furthermore, compounds 2 and 3 displayed significant cytotoxic activity against brine shrimp larvae (Artemia salina) at 10 μg/mL. This is the first report on motility inhibitory and lytic activities of metabolites from an endophytic Fusarium species against the zoospores of the downy mildew pathogen P. viticola.     

Structural characteristics and connection mechanism of gold-catalyzed bridging silicon nanowires

Lateral, single-crystalline silicon nanowires were synthesized using chemical vapor deposition catalyzed by gold nanoparticles deposited on one of the vertical {1 1 1} sidewalls of trenches etched in Si(0 1 1) substrates. Upon encountering the opposing sidewalls of the trenches, the lateral nanowires formed a mechanically strong connection. The bridging connection at the opposing sidewall was observed using high-resolution transmission electron microscopy (TEM) to be epitaxial and unstrained silicon-to-silicon. Using energy-dispersive X-ray spectroscopy in TEM, gold could not be detected at the interface region where the nanowires formed a connection with the opposing sidewall silicon deposit but was detected on the surface adjacent to the impingement region. We postulate that a silicon-to-silicon connection is formed as the gold–silicon liquid eutectic is forced out of the region between the growing nanowire and the opposing sidewall.     

Hollow Reticular Shaped Highly Ordered Rice Husk Carbon for the Simultaneous Determination of Dopamine and Uric Acid

We have prepared activated porous carbon material through simple pyrolysis method from rice husks (rhAC) for sensitive detection of dopamine (DA) and uric acid (UA). The prepared rhAC material was thoroughly characterized using various spectroscopic, microscopic, and electroanalytical techniques. Analysis of the voltammetric data showed that the analytes followed a first order reaction kinetics while following a 2e^?/2H⁺ transfer process. We have discussed the possible oxidation mechanism for the analytes based on the results from our experimental analysis. The rhAC_GCE sensor was tested for interference, reproducibility, and stability. The sensor was also tested to evaluate its applicability in real life.     

Effects of Temperature on The UV-B Sensitivity of Toxic Cyanobacteria Microcystis aeruginosa CS558 and Anabaena circinalis CS537

Rising global temperatures have been suggested to favor cyanobacteria over eukaryotic algae, but UV-B fluxes are also predicted to remain high and may interact with temperature to affect algal growth. To understand the interactive effects of temperature and UV-B radiation, cultures of Microcystis aeruginosa and Anabaena circinalis were grown at either 25 or 30°C and then exposed to an acute irradiance of UV-B (1.4 W m⁻²). Both species showed differences in growth rates at both temperature regimes. The growth rates of M. aeruginosa (0.41 ± 0.02 day⁻¹) and A. circinalis (0.38 ± 0.01 day⁻¹) were higher at 25 and 30°C, respectively. Rates of damage (k) and repair (r) were calculated from the kinetics of change in effective quantum yield, F_v'/F_m'. Analysis of the estimates of r and k shows that M. aeruginosa exhibited relatively high values for both parameters, compared to A. circinalis, at both growth temperatures. In both species, repair rates were higher at 30°C than at 25°C but in A. circinalis damage was also greater at the higher temperature. In contrast, M. aeruginosa showed a lower damage rate at the higher temperature. For both species, the ratio of r:k was higher at the higher temperature. However, the percent inhibition of effective quantum yield by UV-B was greater in A. circinalis than in M. aeruginosa as the r:k was lower A. circinalis. Therefore, it could be concluded that temperature may influence growth and bloom formation of cyanobacteria and that different species may respond differently to UV-B and temperature interactions.     

Effects of branching characteristics and copolymer composition distribution on non-isothermal crystallization kinetics of metallocene LLDPEs

The effects of branch content (BC) and copolymer composition distribution (CCD) on the non-isothermal crystallization kinetics of metallocene m-LLDPEs were studied using modified Avrami analysis, modulated differential scanning calorimetry (MDSC), and Crystaf. Several m-LLDPEs and an m-HDPE - all having comparable M_w and PDI - were experimented. In addition, a ZN-LLDPE was used for comparison purposes. The branch content, unlike the used cooling rates (2-6 °C/min), significantly affected the crystallization behavior. Crystallization peak temperature, , decreased linearly with increasing BC. All the m-LLDPEs showed primary and secondary crystallizations. The secondary crystallization showed to be more pronounced at high BC. The primary crystallization Avrami parameter n for m-HDPE ranged between 3.72 and 4.50, indicating spherulitic crystal growth whereas that for the m-LLDPEs, varied from 2.02 to 5.70. The ZN-LLDPE (having broader composition distribution) offered higher values of and than the m-LLDPEs with similar BC, M_w, and PDI. It, unlike the m-LLDPEs and m-HDPE, fairly agreed with the crystallization kinetic model proposed by Liu et al. The lamella thickness of the m-LLDPEs, L, calculated as per Gibbs-Thomson equation, showed to be in the range 2-16 nm, depending on BC and it decreased approximately following the relationship: L (nm) = 15.0 e^{(−0.0498BC)}.