scholarly journals Preparation and Characterization of a Novel Vinyl Polysiloxane Getter for Hydrogen Elimination

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1853
Author(s):  
Tao Xing ◽  
Yong Xu ◽  
Juying Wu ◽  
Yu Wang ◽  
Lifeng Yan
Keyword(s):  
Hydrogen Generation ◽  
Silicone Oil ◽  
Radiation Stability ◽  
Confined Space ◽  
Space Applications ◽  
Molecular Weights ◽  
Hydrogen Elimination ◽  
Recorded Performances ◽  
Further Development

Hydrogen generation and accumulation in confined spaces poses safety concerns due to its reactivity with oxygen to form explosions and the ability to embrittle metals. Various organic getters have been developed to eliminate hydrogen and minimize these undesired effects; however, these getters are usually powders with low molecular weights and are difficult to apply in complex structures. Polymer getters exhibit the promising features required for confined space applications, where could be readily processed into various shapes and forms. Unfortunately, polymer getters are relatively unexplored and their recorded performances are far from satisfactory. In this work, we report the preparation and characterization of novel vinyl polysiloxane getters. Starting from a methyl vinyl silicone oil prepared by ring-opening polymerization, polysiloxane getters in versatile forms that are adaptable to various environments are prepared by adding Pd/C and then curing. Combined with the thermal and radiation stability of polysiloxane, not only will these new getters be applicable in future applications in the electronic and nuclear industries as hydrogen scavengers, they also serve as platform for further development of polymer getters with superior properties.

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

Synthesis and Characterization of Some New Esters Containing Heterocyclic and Derived From Azo Dyes

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Zena G. Alrecabi ◽  
Zainab Amer ◽  
Naeemah Al-Lami
Keyword(s):  
Schiff Base ◽  
13C Nmr ◽  
Azo Dyes ◽  
Spectral Methods ◽  
Anthranilic Acid ◽  
Heterocyclic Compounds ◽  
Synthesis And Characterization ◽  
Cooh Group ◽  
Molecular Weights

This study including prepared new colored esters containing heterocyclic with high molecular weights. In the first part of work we synthesized azo dyes [1,2] from the reaction p-toluidine with β-naphthol and o-nitro phenol, thin we synthesized Schiff bases [3,4] by the reaction anthranilic acid with benzaldehyde and dimethyl benzaldehyde. The reaction azo dyes (contain OH group) with Schiff base (contain COOH group) these led to produce the new colored esters [A1-A4]. The second part of work was modification the (C=N-) group in esters to heterocyclic compounds by reacting with phenyl iso cyanide to produce new β-lactam [B1-B4] and with anthranilic acid to get new hydroquinazoline [C1-C4]. All these compounds were characterized by physical properties and spectral methods FTIR, 1H-NMR and 13C-NMR.

scholarly journals Semi-Crystalline Hydrophobic Polyamidoamines: A New Family of Technological Materials?

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1018
Author(s):  
Massimo Marcioni ◽  
Jenny Alongi ◽  
Elisabetta Ranucci ◽  
Mario Malinconico ◽  
Paola Laurienzo ◽  
...  
Keyword(s):  
Maximum Stress ◽  
Water Resistance ◽  
Prolonged Exposure ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Molecular Weights ◽  
New Family ◽  
Methylene Groups ◽  
Methane Flame

The hitherto known polyamidoamines (PAAs) are not suitable as structural materials because they are usually water-soluble or swellable in water. This paper deals with the synthesis and characterization of semi-crystalline hydrophobic PAAs (H-PAAs) by combining different bis-sec-amines with bis-acrylamides obtained from C6–C12 bis-prim-amines. H-PAAs were initially obtained in a solution of benzyl alcohol, a solvent suitable for both monomers and polymers. Their number average molecular weights, M¯n, which were determined with 1H-NMR by evaluating the percentage of their terminal units, varied from 6000 to >10,000. The solubility, thermal properties, ignitability and water resistance of H-PAAs were determined. They were soluble in organic solvents, semi-crystalline and thermally stable. The most promising ones were also prepared using a bulk process, which has never been previously reported for PAA synthesis. In the form of films, these H-PAAs were apparently unaffected by water. The films underwent tensile and wettability tests. They showed similar Young moduli (260–263 MPa), whereas the maximum stress and the stress at break depended on the number of methylene groups of the starting bis-acrylamides. Their wettability was somewhat higher than that of common Nylons. Interestingly, none of the H-PAAs considered, either as films or powders, ignited after prolonged exposure to a methane flame.

scholarly journals Purification and characterization of fat body lipase from the greater wax moth, Galleria mellonella (Lepidoptera: Pyralidae)

2019 ◽  
Vol 81 (1) ◽  
Author(s):  
Rahma R. Z. Mahdy ◽  
Shaimaa A. Mo’men ◽  
Marah M. Abd El-Bar ◽  
Emad M. S. Barakat
Keyword(s):  
Metal Ions ◽  
Kinetic Parameters ◽  
Biochemical Characterization ◽  
Galleria Mellonella ◽  
Fat Body ◽  
Specific Activity ◽  
Larval Instar ◽  
Gel Filtration ◽  
Molecular Weights

Abstract Background Insect lipid mobilization and transport are currently under research, especially lipases and lipophorin because of their roles in the production of energy and lipid transport at a flying activity. The present study has been conducted to purify intracellular fat body lipase for the first time, from the last larval instar of Galleria mellonella. Results Purification methods by combination of ammonium sulfate [(NH4)2SO4] precipitation and gel filtration using Sephadex G-100 demonstrated that the amount of protein and the specific activity of fat body lipase were 0.008633 ± 0.000551 mg/ml and 1.5754 ± 0.1042 μmol/min/mg protein, respectively, with a 98.9 fold purity and recovery of 50.81%. Hence, the sephadex G-100 step was more effective in the purification process. SDS-PAGE and zymogram revealed that fat body lipase showed two monomers with molecular weights of 178.8 and 62.6 kDa. Furthermore, biochemical characterization of fat body lipase was carried out through testing its activities against several factors, such as different temperatures, pH ranges, metal ions, and inhibitors ending by determination of their kinetic parameters with the use of p-nitrophenyl butyrate (PNPB) as a substrate. The highest activities of enzyme were determined at the temperature ranges of 35–37 °C and 37–40 °C and pH ranges of 7–9 and 7–10. The partially purified enzyme showed significant stimulation by Ca2+, K+, and Na+ metal ions indicating that fat body lipase is metalloproteinase. Lipase activity was strongly inhibited by some inhibitors; phenylmethylsulfonyl fluoride (PMSF), ethylene-diaminetetractic acid (EDTA), and ethylene glycoltetraacetic acid (EGTA) providing evidence of the presence of serine residue and activation of enzymes by metal ions. Kinetic parameters were 0.316 Umg− 1 Vmax and 301.95 mM Km. Conclusion Considering the purification of fat body lipase from larvae and the usage of some inhibitors especially ion chelating agents, it is suggested to develop a successful control of Galleria mellonella in near future by using lipase inhibitors.

scholarly journals Purification and characterization of bacteriocins-like inhibitory substances from food isolated Enterococcus faecalis OS13 with activity against nosocomial enterococci

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmed O. El-Gendy ◽  
Dag A. Brede ◽  
Tamer M. Essam ◽  
Magdy A. Amin ◽  
Shaban H. Ahmed ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Antimicrobial Agents ◽  
Food Samples ◽  
Proteinase K ◽  
Clinical Samples ◽  
Bile Salt Hydrolase ◽  
Antibiotic Resistant ◽  
Molecular Weights ◽  
Global Threat

AbstractNosocomial infections caused by enterococci are an ongoing global threat. Thus, finding therapeutic agents for the treatment of such infections are crucial. Some Enterococcus faecalis strains are able to produce antimicrobial peptides called bacteriocins. We analyzed 65 E. faecalis isolates from 43 food samples and 22 clinical samples in Egypt for 17 common bacteriocin-encoding genes of Enterococcus spp. These genes were absent in 11 isolates that showed antimicrobial activity putatively due to bacteriocins (three from food, including isolate OS13, and eight from clinical isolates). The food-isolated E. faecalis OS13 produced bacteriocin-like inhibitory substances (BLIS) named enterocin OS13, which comprised two peptides (enterocin OS13α OS13β) that inhibited the growth of antibiotic-resistant nosocomial E. faecalis and E. faecium isolates. The molecular weights of enterocin OS13α and OS13β were determined as 8079 Da and 7859 Da, respectively, and both were heat-labile. Enterocin OS13α was sensitive to proteinase K, while enterocin OS13β was resistant. Characterization of E. faecalis OS13 isolate revealed that it belonged to sequence type 116. It was non-hemolytic, bile salt hydrolase-negative, gelatinase-positive, and sensitive to ampicillin, penicillin, vancomycin, erythromycin, kanamycin, and gentamicin. In conclusion, BLIS as enterocin OS13α and OS13β represent antimicrobial agents with activities against antibiotic-resistant enterococcal isolates.

Characterization of satellite components assembly for responsive space applications

2011 ◽  
Author(s):  
David Mascarenas ◽  
David Macknelly ◽  
Josh Mullins ◽  
Heather Wiest ◽  
Gyuhae Park ◽  
...  
Keyword(s):  
Space Applications

Radiation stability of mixed tin–lead halide perovskites: Implications for space applications

2021 ◽  
Vol 230 ◽  
pp. 111232
Author(s):  
Brandon K. Durant ◽  
Hadi Afshari ◽  
Shashi Sourabh ◽  
Vishal Yeddu ◽  
Matthew T. Bamidele ◽  
...  
Keyword(s):  
Radiation Stability ◽  
Space Applications ◽  
Halide Perovskites ◽  
Lead Halide

scholarly journals Development and characterization of silicon dioxide clad silicon carbide optics for terrestrial and space applications

2021 ◽  
Author(s):  
Tayaramma D.P.V. Jalluri ◽  
Girish M. Gouda ◽  
Arjun Dey ◽  
B. Rudraswamy ◽  
K.V. Sriram
Keyword(s):  
Silicon Carbide ◽  
Silicon Dioxide ◽  
Space Applications

scholarly journals An Experimental Characterization of TORVEastro, Cable-Driven Astronaut Robot

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 21
Author(s):  
Francesco Samani ◽  
Marco Ceccarelli
Keyword(s):  
Mechanical Design ◽  
Vision System ◽  
Service Robot ◽  
Test Results ◽  
Operation Performance ◽  
Space Applications ◽  
Outdoor Space ◽  
Motion Characteristics ◽  
Three Degree Of Freedom

TORVEastro robot design is presented with a built prototype in LARM2 (Laboratory of Robot Mechatronics) for testing and characterizing its functionality for service in space stations. Several robot astronauts are designed with bulky human-like structures that cannot be convenient for outdoor space service in monitoring and maintenance of the external structures of orbital stations. The design features of TORVEastro robot are discussed with its peculiar mechanical design with 3 arm-legs as agile service robot astronaut. A lab prototype is used to test the operation performance and the feasibility of its peculiar design. The robot weighs 1 kg, and consists of a central torso, three identical three-degree of freedom (DoF) arm–legs and one vision system. Test results are reported to discuss the operation efficiency in terms of motion characteristics and power consumption during lab experiments that nevertheless show the feasibility of the robot for outdoor space applications.

Sign in / Sign up

Export Citation Format

Share Document