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

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

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

Optimization of material removal rate and surface characterization of wire electric discharge machined Ti-6Al-4V alloy by response surface method

Wire electric discharge machining (WEDM) is one of the foremost methods which has been utilized for machining hard-to-cut materials like Titanium alloys. However, there is a need to optimize their important operating parameters to achieve maximum material removal rate (MRR). The present paper investigates the effect of control factors like current, pulse on time (Ton), pulse off time (Toff) on MRR of machining of Ti-6Al-4V alloy. The study showed that, increase in current from 2 A to 6 A results in a significant increase in MRR by 93.27% and increase in Ton from 20 μs to 35 μs improved the MRR by 7.98%, beyond which there was no improvement of MRR. The increase in Toff showed a counterproductive effect. Increase in Toff from 10 μs to 30 μs showed an almost linear decrease in MRR by 52.77%. Morphological study of the machined surface showed that cut surface consists of recast layer on which microcracks were present, and revealed the presence of globules, ridge-structured formations of recast layers and voids. In addition, a regression model was developed to predict the MRR with respect to the control factors, which showed a good prediction with an R2 value of 99.67%

A splice variant of the myosin phosphatase regulatory subunit tunes arterial reactivity and suppresses response to salt loading

© 2016 the American Physiological Society. The cGMP activated kinase cGK1α is targeted to its substrates via leucine zipper (LZ)-mediated heterodimerization and thereby mediates vascular smooth muscle (VSM) relaxation. One target is myosin phosphatase (MP), which when activated by cGK1α results in VSM relaxation even in the presence of activating calcium. Variants of MP regulatory subunit Mypt1 are generated by alternative splicing of the 31 nt exon 24 (E24), which, by changing the reading frame, codes for isoforms that contain or lack the COOH-terminal LZ motif (E24+/LZ−; E24−/LZ+). Expression of these isoforms is vessel specific and developmentally regulated, modulates in disease, and is proposed to confer sensitivity to nitric oxide (NO)/cGMP-mediated vasorelaxation. To test this, mice underwent Tamoxifen-inducible and smooth muscle-specific knockout of E24 (E24 cKO) after weaning. Deletion of a single allele of E24 (shift to Mypt1 LZ+) enhanced vasorelaxation of first-order mesenteric arteries (MA1) to diethylamine-NONOate (DEA/NO) and to cGMP in permeabilized and calcium-clamped arteries and lowered blood pressure. There was no further effect of deletion of both E24 alleles, indicating high sensitivity to shift of Mypt1 isoforms. However, a unique property of MA1s from homozygous E24 cKOs was significantly reduced force generation to α-adrenergic activation. Furthermore 2 wk of high-salt (4% NaCl) diet increased MA1 force generation to phenylephrine in control mice, a response that was markedly suppressed in the E24 cKO homozygotes. Thus Mypt1 E24 splice variants tune arterial reactivity and could be worthy targets for lowering vascular resistance in disease states

Synthesis and crystal structure of tripeptide fragment of elastin

Boc-Gly-Val-Pro-OBzl, a protected tripeptide fragment of repeating sequences of mammalian elastic protein elastin was synthesized and characterized by X-ray diffraction method. The sequence C24 H35 N3 O6 crystallizes in the orthorhombic space group P212121 with the parameters a = 9.4700(11) Å, b = 9.8980(8) Å, c = 26.721(3) Å, V = 2504.7(4) Å3 and Z = 4. The final residual factor is 0.0670. The structure exhibits intra and intermolecular hydrogen bonds

Synthesis and crystal structure of 2-benzoyl-4-methyl phenyl benzoate

The crystal structure of the title compound, C21H16O3, has been determined. The compound crystallizes in triclinic space group PĪ with cell parameters a = 9.2240(9) Å, b = 9.8050(8) Å, c = 10.1610(11) Å, α = 94.749(6)∘, β = 112.544(4)∘, γ = 102.145(6)∘ and Z = 2. The structure exhibits both intra and intermolecular interactions of the type C–H ⋅s O. The intermolecular interaction between the molecules form centrosymmetric dimers

Synthesis and X-ray structure conformation of novel unsymmetrical 1,4-dihydropyridine

Methyl 2,6-dimethyl-5-(2-methylphenylcarbamoyl)-4-(3-nitrophenyl)-1,4-dihydropy ridine-2-carboxylate (3) was prepared by known Hantzch method and its structure was elucidated by X-ray diffraction method