The Number of Accumulated Photons and the Quality of Stimulated Emission Depletion Lifetime Images

Time binning is used to increase the number of photon counts in the peak channel of stimulated emission depletion fluorescence lifetime decay curves to determine how it affects the resulting lifetime image. The fluorescence lifetime of the fluorophore, Alexa Fluor 594 phalloidin, bound to F‐actin is probed in cultured S2 cells at a spatial resolution of ~40 nm. This corresponds to a 10‐fold smaller probe volume compared to confocal imaging, and a reduced number of photons contributing to the signal. Pixel‐by‐pixel fluorescence lifetime measurements and error analysis show that an average of 40 ± 30 photon counts in the peak channel with a signal‐to‐noise ratio of 20 is enough to calculate a reliable fluorescence lifetime from a single exponential fluorescence decay. No heterogeneity in the actin cytoskeleton in different regions of the cultured cells was measured in the 40–400 nm spatial regime.     

Expeditious,Nano-BF3 · SiO2-Catalyzed Michaelis–Arbuzov Reaction in an Ionic Liquid: Synthesis of Privileged Aryl/Heterocyclic Phosphonates

An expeditious, simple, and green method was developed for the synthesis of privileged aryl/heterocyclicphosphonates, 8(a–c) to 13(a–c) through Michaelis–Arbuzov reaction of aryl/heterocyclic halides (Br), 1–6, and trialkylphosphites, 7(a–c), in room-temperature ionic liquid [bbim]Br using heterogeneous Lewis catalyst, nano-silica-supported boron trifluoride (BF₃-SiO₂). The advantages of this protocol are simplicity, good yield of the products, less reaction time (20–38 min), mild reaction conditions, easy workup, and reusability of the catalyst and ionic liquid. It is demonstrated that nano-BF₃-SiO₂ is a recoverable and easy accessible catalyst for the formation of C(sp²)-P bond in an ionic liquid.     

Synthesis of techentium-99m labeled clinafloxacin (99mTc�CCNN) complex and biological evaluation as a potential Staphylococcus aureus infection imaging agent

In the present study synthesis of the ^99mTc?CCNN complex and its efficacy as a prospective Staphylococcus aureus (S. aureus) infection imaging agent was assessed. The ^99mTc?CCNN complex was characterized in terms of stability in saline, serum, in vitro binding with S. aureus and in vivo percent absorption in male Wister rats (MWR) infected with live and heat killed S. aureus. Radiochemically the ^99mTc?CCNN complex showed stable behavior in saline and serum at different intervals. At 30 min after reconstitution the complex showed maximum radiochemical purity (RCP) yield of 97.55 ± 0.22%. The RCP yield decreased to 90.50 ± 0.18% within 240 min. In serum, 18.15% unwanted side product was appeared within 16 h of the incubation. In vitro saturated binding with S. aureus was observed at different intervals with a 62.00% maximum at 90 min. Normal percent in vivo uptake was observed in MWR artificially infected with live S. aureus with a five times higher in the infected muscle as compared to the inflamed and normal muscles. No difference in the percent uptake of the complex in MWR infected with heat killed S. aureus in the infected, inflamed and normal muscles were observed. Based on the promising in vitro and in vivo radiochemical and biological characteristics, we recommend the ^99mTc?CCNN complex for in vivo localization of the S. aureus infectious foci.     

Radiolabeling of gemifloxacin with technetium-99m and biological evaluation in artificially <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> infected rats

In the current investigation complexation of the gemifloxacin (GIN) with technetium-99 m (^99mTc) and its biological evaluation in artificially Streptococcus pneumoniae (S. pneumoniae) infected rats was assessed as potential S. pneumoniae infection radiotracer. Radiochemically the ^99mTc-GIN complex was further analyzed in terms of stability in saline, in vitro stability in serum at 37 °C, in vitro binding with S. pneumoniae and biodistribution in artificially S. pneumoniae (living and heat killed) infected rats. The complex was found 97.25 ± 0.25% radiochemically stable in saline at 30 min after reconstitution. The stability of the ^99mTc-GIN complex was decreased to 90.50 ± 0.20% within 240 min after reconstitution. In serum the ^99mTc-GIN complex showed stable profile with the appearance of 18.85% free tracer within 16 h of incubation. The ^99mTc-GIN complex showed saturated in vitro binding with S. pneumoniae after different intervals. Almost five fold uptake was observed in living S. pneumoniae infected muscle of the rats as compared to the inflamed and normal muscle. No significant difference in the uptake of heat killed S. pneumoniae infected, inflamed and normal muscles of the rats. The high RCP yield in saline, in vitro permanence in serum, in vitro binding with living S. pneumoniae and biodistribution in artificially S. pneumoniae infected rats we recommend the ^99mTc-GIN as potential S. pneumoniae infection radiotracer.     

Brain delivery of transferrin coupled indinavir submicron lipid emulsions--pharmacokinetics and tissue distribution

Indinavir, an antiretroviral protease inhibitor used in treatment of HIV infection has limited penetration into brain due to efflux of P-glycoprotein. The aim of this work was to develop transferrin coupled submicron lipid emulsions (SLEs) containing indinavir for delivery to brain. Stearylamine containing SLEs were prepared, characterized, tested for stability and optimized formulation (SLE-4) was developed. Transferrin was coupled to get SLE-6 by water soluble EDC method and purified by gel filtration. The coupled transferrin was quantified by modified Bradford dye assay method. The fluorescent dye (DiD oil) incorporated SLEs were used to check the brain specific delivery of SLEs. The in vivo pharmacokinetic and tissue distribution were conducted in mice. During pharmacokinetic studies, there was no significant difference in the serum levels of indinavir from SLE-1, SLE-4 and SLE-6 formulations at all time points. In tissue distribution studies the therapeutic availability (TA) of indinavir in brain from SLE-6 was 4.69, 3.1 and 1.7 times higher than drug solution, SLE-1 and SLE-4 respectively whereas, the TA of indinavir from SLE-4 was 2.76 and 1.82 times the drug solution and SLE-1. The brain to serum ratios with SLE-6 were above one indicates the brain specific delivery. The brain delivery of indinavir was improved with transferrin ligand attachment to SLEs by receptor mediated transcytosis.     

Production of ROS by photosensitized anthracene under sunlight and UV-R at ambient environmental intensities

The aim of this study was to analyze the photostability and phototoxicity mechanism of anthracene (ANT) in a human skin epidermal cell line (HaCaT) at ambient environmental intensities of sunlight/UV‐R (UV‐A and UV‐B). Photomodification of ANT under sunlight/UV‐R exposure produced two photoproducts, anthrone and 9,10 anthracenedione. Generation of ¹O₂, O₂^?? and ^?OH was measured under UV‐R/sunlight exposure. Involvement of reactive oxygen species (ROS) was further substantiated by their quenching with free radical quenchers. Photodegradation of 2‐deoxyguanosine and linoleic acid peroxidation showed that ROS were mainly responsible for ANT phototoxicity. ANT generates significant amount of intracellular ROS in cell line. Maximum cell viability (85%) was reduced under sunlight exposure (30 min). Results of MTT assay accord NRU assay. ANT (0.01 μg mL^?1) induced cell‐cycle arrest at G1 phase. RT‐PCR demonstrated constitutive inducible mRNA expression of CYP 1A1 and 1B1 genes. Photosensitive ANT upregulates CYP 1A1 (2.2‐folds) and 1B1 (4.1‐folds) genes. Thus, the study suggests that ROS and DNA damage were mainly responsible for ANT phototoxicity. ANT exposure may be deleterious to human health at ambient environmental intensities reaching the earth’s surface through sunlight.     

Investigation of Nutrient Feeding Strategies in a Countercurrent Mixed-Acid Multi-Staged Fermentation: Experimental Data

Nutrients are essential for microbial growth and metabolism in mixed-culture acid fermentations. Understanding the influence of nutrient feeding strategies on fermentation performance is necessary for optimization. For a four-bottle fermentation train, five nutrient contacting patterns (single-point nutrient addition to fermentors F1, F2, F3, and F4 and multi-point parallel addition) were investigated. Compared to the traditional nutrient contacting method (all nutrients fed to F1), the near-optimal feeding strategies improved exit yield, culture yield, process yield, exit acetate-equivalent yield, conversion, and total acid productivity by approximately 31%, 39%, 46%, 31%, 100%, and 19%, respectively. There was no statistical improvement in total acid concentration. The traditional nutrient feeding strategy had the highest selectivity and acetate-equivalent selectivity. Total acid productivity depends on carbon–nitrogen ratio.     

Application of Liquid-Liquid Microextraction-High-Performance Thin-Layer Chromatography for Preconcentration and Determination of Phenolic Compounds in Aqueous Samples

JPC – Journal of Planar Chromatography – Modern TLC - A novel liquid-phase microextraction method coupled with high-performance thin-layer chromatography (HPTLC) for preconcentration,...     

Enhanced Electron Transfer Rates by AC Voltammetry for Ferrocenes Attached to the End of Embedded Carbon Nanofiber Nanoelectrode Arrays

The effect of the interior structure of carbon nanomaterials on their electrochemical properties is not well understood. We report here the electron transfer rate (ETR) of ferrocene (Fc) molecules covalently attached to the exposed end of carbon nanofibers (CNFs) in an embedded nanoelectrode array. The ETR in normal DC voltammetry was found to be limited by the conical graphitic stacking structure interior of CNFs. AC voltammetry, however, can cope with this intrinsic materials property and provide over 100 times higher ETR, likely by a new capacitive pathway. This provides a new method for high‐performance electroanalysis using CNF nanoelectrodes.