96 research outputs found
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
Use of pregabalin for nonconvulsive seizures and nonconvulsive status epilepticus
AbstractPurposeTo determine the efficacy of pregabalin (PGB) in treatment of frequent nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE) in critically ill patients.MethodsIn this retrospective study, 21 patients were identified as having received pregabalin for the treatment of NCS as determined by continuous electroencephalographic monitoring. The patients were considered to be responders if their seizures were terminated within 24h of initiation of PGB without the addition of another antiepileptic agent.ResultsOf the 21 patients who received PGB for treatment of NCS or NCSE, 11 (52%) were responders. PGB was administered via a nasogastric tube or orally and was the 2nd to 4th agent used. The average initial dose and total daily dose of PGB was similar in the responders and non-responders (342mg vs. 360mg, respectively). PGB was more effective in aborting NCS (9 patients, 82%) than NCSE (2 patients, 18%). Of the 9 brain tumor patients, PGB resulted in seizure cessation in 67% (6 patients). In contrast, all patients with hypoxic injury (4) did not respond to PGB. The responders were noted to have better clinical outcome (64% vs. 9% discharged home). Most of the patients tolerated the medication without any significant short term adverse effects, except two patients who were noted to have dizziness and sedation.ConclusionsPregabalin may be safe option for add-on treatment for nonconvulsive seizures in critically ill patients when conventional therapy fails
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
Static Compaction Using Overlapped Restoration and Segment Pruning
: We propose a new technique for static compaction of test sequences. Our method is based on two key ideas: (1) overlapped vector restoration, and (2) identification, pruning, and re-ordering of segments. Overlapped restoration provides a significant computational advantage for large circuits. Segments partition the compaction problem into sub-problems. Segments are identified, dynamically pruned and re-ordered to achieve further compaction and speed up. When compared to the fastest method proposed in [8], our method was 5 to 30 times faster on ISCAS circuits and 20 to 50 times faster on large, industrial designs. The new algorithm was able to successfully process large industrial designs that could not be handled by earlier techniques [8] in 2 CPU days. I. Introduction Reduction in test set size can be achieved using static or dynamic test set compaction algorithms. Dynamic techniques [9, 10, 14, 15, 16] perform compaction concurrently with the test generation process. These techniq..
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