Electrical Breakdown of Anodized Structures in a Low Earth Orbital Environmental

A comprehensive set of investigations involving arcing on a negatively biased anodized aluminum plate immersed in a low density argon plasma at low pressures (P(sub O), 7.5 x 10(exp -5) Torr) have been performed. These arcing experiments were designed to simulate electrical breakdown of anodized coatings in a Low Earth Orbital (LEO) environment. When electrical breakdown of an anodized layer occurs, an arc strikes, and there is a sudden flux of electrons accelerated into the ambient plasma. This event is directly followed by ejection of a quasi-neutral plasma cloud consisting of ejected material blown out of the anodized layer. Statistical analysis of plasma cloud expansion velocities have yielded a mean propagation velocity, v = (19.4 +/- 3.5) km/s. As the plasma cloud expands into the ambient plasma, energy in the form of electrical noise is generated. The radiated electromagnetic noise is detected by means of an insulated antenna immersed in the ambient plasma. The purpose of the investigations is (1) to observe and record the electromagnetic radiation spectrum resulting from the arcing process. (2) Make estimates of the travel time of the quasi-neutral plasma cloud based on fluctuations to several Langmuir probes mounted in the ambient plasma. (3) To study induced arcing between two anodized aluminum structures in close proximity

Nasal PMN response to repeated challenge with endotoxin in healthy volunteers

We have employed nasal challenge with lipopolysaccharide (LPS) followed by nasal lavage (NL) to experimentally induce and examine upper airway inflammation in human volunteers. It is unclear however whether adaptation within individuals occurs following repeated nasal challenge. This was a pilot study to determine if repeated nasal LPS challenge yields attenuation of markers of inflammation (primarily neutrophil response) in the NL fluid of healthy humans

N,N'Bis(2-chloro-phen-yl)-4-(4-chloro-phen-yl)-2,6-dimeth-yl-1,4-dihydro-pyridine-3,5-dicarboxamide

In the title compound, Csb 27Hsb 22Clsb 3Nsb 3Osb 2, the dihydro-pyridine ring has a boat conformation. The mol-ecules are linked by N-H⋅sO, N-H⋅sCl, C-H⋅sN and C-H⋅sO hydrogen bonds

GSTM1 modulation of IL-8 expression in human bronchial epithelial cells exposed to ozone

Exposure to the major air pollutant ozone can aggravate asthma and other lung diseases. Our recent study in human volunteers has shown that the glutathione S-transferase mu 1 (GSTM1) null genotype is associated with increased airway neutrophilic inflammation induced by inhaled ozone. The aim of this study was to examine the effect of GSTM1 modulation on interleukin 8 (IL-8) production in ozone-exposed human bronchial epithelial cells (BEAS-2B) and the underlying mechanisms. Exposure of BEAS-2B cells to 0.4 ppm ozone for 4 h significantly increased IL-8 release with a modest reduction in intracellular reduced glutathione (GSH). Ozone exposure induced reactive oxygen species (ROS) production and NFκB activation. Pharmacological inhibition of NFκB activation or mutation of IL-8 promoter at κB-binding site significantly blocked ozone-induced IL-8 production or IL-8 transcriptional activity, respectively. Knockdown of GSTM1 in BEAS-2B cells enhanced ozone-induced NFκB activation and IL-8 production. Consistently, ozone-induced overt increase in IL-8 production was detected in GSTM1-null primary human bronchial epithelial cells. In addition, supplementation with reduced GSH inhibited ozone-induced ROS production, NFκB activation and IL-8 production. Taken together, GSTM1 deficiency enhances ozone-induced IL-8 production, which is mediated by generated ROS and subsequent NFκB activation in human bronchial epithelial cells

Children’s residential exposure to selected allergens and microbial indicators: endotoxins and (1→3)-β-D-glucans

Objectives: The study was aimed at assessment of exposure to endotoxins, (1→3)-β-D-glucans and mite, cockroach, cat, dog allergens present in settled dust in premises of children as agents which may be significantly correlated with the occurrence of allergic symptoms and diseases in children. Materials and Methods: The study covered 50 homes of one- or two-year-old children in Poland. Samples of settled dust were taken from the floor and the child's bed. The levels of (1→3)-β-D-glucans (floor), endotoxins (floor) and allergens of mite, cat, dog and cockroach (floor and bed) were analyzed. Results: Average geometric concentrations (geometric standard deviation) of endotoxins, (1→3)-β-D-glucans, Der p1, Fel d1, Can f1 and Bla g1 in children homes were on the floor 42 166.0 EU/g (3.2), 20 478.4 ng/g (2.38), 93.9 ng/g (6.58), 119.8 ng/g (13.0), 288.9 ng/g (3.4), 0.72 U/g (4.4) and in their beds (only allergens) 597.8 ng/g (14.2), 54.1 ng/g (4.4), 158.6 ng/g (3.1) 0.6 U/g (2.9), respectively. When the floor was covered with the carpet, higher concentrations of endotoxins, (1→3)-β-D-glucans and allergens (each type) were found in the settled dust (p < 0.05). The trend was opposite in case of allergens (except dog) analyzed from bed dust and significantly higher concentrations were found in the rooms with smooth floor (p < 0.05). Conclusions: Among the analyzed factors only the type of floor significantly modified both the level of biological indicators and allergens. The results of this study could be the base for verifying a hypothesis that carpeting may have a protective role against high levels of cockroach, dog and cat allergens

Structural, Quantum Chemical and Spectroscopic Investigations on Photophysical Properties of Fluorescent Saccharide Sensor: Theoretical and Experimental Studies

Structure, Hirshfeld surface, spectra and photophysical properties of boronic acid-based carbohydrate sensor (5-fluoro-2-methoxyphenyl) boronic acid (BA8) has been reported by experimental methods (XRD/FT-IR/UV/steady state fluorescence) and theoretically by Density functional theory (DFT) model with most accurate functionals (B3LYP/CAM-B3LYP/ M06-2X). The comparison of theoretical and experimental data exhibited good agreement. Natural bond orbital (NBO) and frontier molecular orbitals (FMOs) have been analysed. The sensing ability of the compound with carbohydrates (D-glucose and D-fructose) were studied by UV/fluorescence spectra. The variation of absorbance and fluorescence on pH was rationale with the estimated acid-base dissociation constants (pKa). Quantum yield (phi) and fluorescence lifetimes (tau) for the compound and its esters with sugars were calculated. The results of absorbance, fluorescence measurements and calculated photophysical properties indicated fairly selectivity of BA8 with fructose more than the glucose, which is ascertained from both experimental and theoretical results

2-(4-Methylphenyl)-2-oxoethyl 3,4-dimethoxybenzoate

In the title compound, C18H18O5, the dihedral angle between the mean planes of the two aromatic rings is 66.55 (8)°. The crystal packing features by intermolecular C—H...O contacts

Methyl 2-(benzoyloxy)benzoate

In the title compound, C15H12O4, the dihedral angle between the two aryl rings is 68.19 (9)°. In the crystal, molecules are linked by C—H...π interactions forming chains along the b-axis direction. The chains are linked by offset π–π interactions [intercentroid distance = 3.6806 (14) Å], forming sheets lying parallel to (10-1)