Feasibility Exploration of Laser‐based Techniques for Characterization of a Flashing Jet

Two‐phase flows hold an interest in many areas of science and engineering. In the safety field, one such topic is the accidental release of flammable and toxic pressure‐liquefied gases. In case of such a release, a flashing vapor explosion takes place resulting in a very dense two‐phase cloud. If the released substance is flammable, this cloud can be combustible and can lead to deflagration or detonation. For understanding the source processes of flashing and risk assessment, data related to cloud characteristics (i.e. droplet size, velocity etc.) is needed especially in the near region of the release. Due to the non‐equilibrium nature of the near field regions accurate data measurement is not possible with intrusive techniques. Therefore, laser‐based optical techniques (like Particle Image Velocimetry (PIV), Particle Tracking Velocimetry and Sizing (PTVS), Phase Doppler Anemometry (PDA) etc.) present the only possibility to obtain information for particle diameter and velocity evolution in this harsh environment.     

Determination of fumonisins B1 and B2 in corn by liquid chromatography/mass spectrometry with immunoaffinity column cleanup: single-laboratory method validation

A single-laboratory method validation was conducted to establish the effectiveness of an immunoaffinity column cleanup procedure followed by liquid chromatography/mass spectrometry (LCIMS) for the determination of fumonisins B1 and B2 (FBI + FB2) in corn. The test portion is extracted with acetonitrile-methanol-water (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an immunoaffinity column. FB1 + FB2 are removed with methanol and directly determined by reversed-phase LC with MS detection using selected-ion monitoring of 2 characteristic ions in each case. Test portions of blank corn samples were spiked with a mixture of FB1 + FB2 to give total levels of 200 and 500 ng/g, respectively. Recoveries of both FB1 and FB2 from spiked samples averaged 90.4-101%. Based on results for spiked raw corn (triplicates at 2 levels), the relative standard deviation for repeatability ranged from 2.8 to 7.1%. The accuracy of the method was demonstrated by analysis of Food Analysis Performance Assessment Scheme (FAPAS) test material. The method was also applied to a small survey of processed corn products such as corn chips, cornflakes, and popcorn.     

Freezing and Melting of Water Confined in Silica Nanopores

In nanosized pores, liquid water can be thermodynamically stable down to temperatures well below the limit of homogeneous nucleation of bulk water (～235 K). Studies of water in such pores therefore offer an opportunity to reveal the anomalous behavior of deeply supercooled water. Herein we focus on recent studies of the limits of freezing and melting of water in the cylindrical pores of ordered mesoporous silicas with pore diameters in the range of 2–10 nm, based on vapor sorption measurements, calorimetric studies, NMR spectroscopy and cryoporometry, and neutron diffraction studies.     

(Liquid + liquid) equilibria of (water + propionic acid + methyl isoamyl ketone or diisobutyl ketone or ethyl isoamyl keton) at T = 298.2 K

(Liquid + liquid) equilibrium (LLE) data for (water + propionic acid + solvent) were measured at T = 298.2 K and atmospheric pressure. The solvents were methyl isoamyl ketone (5-methyl-2-hexanone), ethyl isoamyl ketone (5-methyl-3-heptanone) and diisobutyl ketone. The tie-line data were correlated by means of the NRTL and UNIQUAC equation, and compared with results predicted by the UNIFAC method. A comparison of the extracting capabilities of the solvents was made with respect to distribution coefficients, separation factors, and solvent free selectivity bases.     

Incorporation of an allene unit into 1,4-dihydronaphthalene: generation of 1,2-benzo-1,4,5-cycloheptatriene and its dimerization

1-Bromo-1-fluoro-[1a,2,7,7a]-tetrahydro-1H-cyclopropa[b]naphthalene (19) has been prepared by the addition of bromofluorocarbene to 1,4-dihydronaphthalene (18). Treatment of a solution of 19 in dry ether with MeLi afforded the tricyclic hydrocarbon 17, resulting from the intramolecular C-H insertion of carbene 16, and two dimerization products, the head-to-head 20 and head-to-tail 21 allene dimers, confirming the formation of title cycloallene 15 as a reactive intermediate. B3LYP/6-31G(d) calculation predicts the activation barriers for insertion product 17 and allene product 15 as 3.70 and 9.52 kcal/mol, respectively. This prediction was in good agreement with our experimental results.     

Characterization and in vitro release kinetics of chitosan based biocomposites from Scotch Bonnets

The main aim of this study is to formulate the combination of the bioactive composite containing chitosan/β -tricalcium phosphate (CH/β-TCP) as potential drug delivery platforms for the sustained release of antibiotics. Herein the mode of amoxicillin (AMX) maintained in the β-TCP/chitosan composite was characterized using XRD, FT-IR to confirm the phase purity and functional groups. SEM was used to examine the size and shape of particles. The SEM images of the biocomposites after drug release confirmed that they are biodegradable. In vitro drug release experiments in PBS (pH 7.4) revealed a sustained release profile in a neutral medium. Drug release profiles were evaluated according to five different kinetic models including Zero Order, First Order, Higuchi, Hixon Crowel, and Korsmeyer-Peppas. The release profile was best expressed by the Korsmeyer Peppas model because the results showed high linearity. Overall, the positive effect of chitosan coating on the drug elution profile of β-TCP as carriers for the controlled delivery of antibiotics was regarded as biocompatible for the controlled drug delivery system.     

Synthesis, characterization and aggregation behaviour of novel peripherally tetra-substituted octacationic water soluble metal-free and metallophthalocyanines

In this study, a new phthalonitrile derivative 3 bearing 1,3-bis[3(dimethylamino)phenoxy]propan-2-ol 1, metal-free phthalocyanine (Pc) 4, metallophthalocyanines (MPcs) 5–7 and their quaternized derivatives 4a–7a were synthesized. Metal-free Pc 4 was prepared by cyclotetramerization of phthalonitrile derivate 3 and MPcs 5–7 were synthesized by heating 3 with NiCl₂, CoCl₂ and CuCl₂ in n-pentanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, respectively. Quaternization of the dimethylamino functionality produced quaternized octacationic water soluble metal-free, Ni, Co and Cu Pcs which were soluble in water, DMF, DMSO. The aggregation behaviour of these compounds were investigated in different concentrations of chloroform for metal-free, Ni, Co and Cu Pcs. The effect of solvents on absorption spectra were studied in various organic solvents. The novel compounds were characterized using IR, ¹H-, ¹³C NMR, UV–vis and MS spectral data.     

The effect of UV-A (352 nm) stress on chlorophyll fluorescence,chlorophyll a content,thickness of upper cortex and determinate DNA damage in Physcia semipinnata

In the present study, Physcia semipinnata samples were exposed to UV-A (352 nm) in 20 J m^?2 for 24 h, 48 h and 72 h to seek the alterations in the PSII photosynthetic quantum yield, thallus anatomy and DNA mutation rate in response to radiation. The Fv/Fm ratio decreased in P. semipinnata following exposure to UV-A for 24 h, 48 h and 72 h. The data of the present study reported that Chla degradation occurred by exposition of UV-A for 24 h, 48 h and 72 h. Photobiont size and thickness of upper cortex layer also showed a gradually decrease in P. semipinnata thallus sections during 24 h, 48 h and 72 h. The thickness of the upper cortex layer, exposed to UV-A for 72 h, of P. semipinnata thallus reduced 64%, compared with control. The random amplified polymorphic DNA (RAPD) technique was used to detect DNA damage. The main changes observed in the RAPD profiles resulted in both appearance and disappearance of different bands and variation of their intensity. According to RAPD assay, the genetic distance between the control group and 24 h, 48 h and 72 h UV-A exposed, groups was found 56%, 78% and 84%, respectively.