Oxygen sensitive paper

Paper is impregnated with mixture of methylene blue and ethylenediaminetetraacetic acid. Methylene blue is photo-reduced to leuco-form. Paper is kept isolated from oxygen until ready for use. Paper can be reused by photo-reduction after oxygen exposure

The preparation of ketene dithioacetals and thiophenes from chloropyridines containing an active methylene group

The base catalysed reaction of carbon disulphide with the active methylene groups of chloropyridines 4 and 7, followed by alkylation with reagents which also contain active methylene groups, lead to ketene dithioacetals. Further reaction with base afforded highly substituted thiophenes

Perbandingan Jumlah Koloni Bakteri Klebsiella Pneumoniae Pada Media Eosin Methylene Blue (Emb) Dan Media Endo Agar Plate (Eap)

Background: Klebsiella pneumoniae is a normal flora bacteria which commonly found on tractus digestivus. The laboratory measurement can be conducted by calculating the number of germ or bacteria which is inoculated on Eosin Methylene Blue and Endo Agar Plate culture medium. The present study aims to compare the number of bacterial colonies of Klebsiella pneumoniae which is regrown on Eosin Methylene Blue Agar and Endo Agar Plate culture medium. Method: This present study is true experiment research which uses Klebsiella pneumoniae as the main sample. The study began by regrowing Klebsiella pneumoniae on Eosin Methylene Blue and Endo Agar Plate. All the deposited- Klebsiella pneumoniae is incubated at the temperature of 37oC for 48 hours and calculated. Furthermore, the experiment is repeated for 16 times to prove all the obtained data repeatable. All the obtained data is statistically analyzed using paired T-test with a confidence level of 95%. Result: The result shows that the average number of Klebsiella pneumoniae bacteria colonies grown on Eosin Methylene Blueand Endo Agar Plate are 67 colonies forming unit (CFU)/ml and 64 colonies forming unit (CFU)/ml, respectively. Furthermore, statistical analysis using paired T-test confirmed that there is no significant difference of Klebsiella pneumoniae colonies number grown on Eosin Methylene Blue and Endo Agar Plate culture mediums. It is based on the significance value (p-value) showing 0,664 which is higher than the significant level (α = 0,05) (p-value > 0,05). Conclusion: There is no significant difference of Klebsiella pneumoniae colonies number grown on Eosin Methylene Blue and Endo Agar Plate culture medium

Exploratory study on the effects of novel diamine curing agents and isocyanate precursors on the properties on new epoxy and urethane adhesives

Aromatic diamines based on diphenyl sulfone and benzophenone were studied as epoxy adhesive curing agents. Previously found differences in adhesive strengths for meta vs para orientation were not found in these series. The use of aluminum and alumina as fillers in a m,m prime-methylene dianiline-cured epoxy adhesive was not found to be beneficial to adhesive strength. Alumina filled adhesives had much lower strength than unfilled adhesives. The unfilled m,m prime-methylene dianiline-based epoxy adhesive had excellent resistance to moisture relative to a p,p prime-methylene dianiline-based adhesive and maintained good strengths up to 250 F. A glass fiber composite based on a m,m prime-methylene dianiline-cured epoxy appeared to be equivalent to the p,p prime-methylene dianiline-cured epoxy as judged by short beam shear tests

Far-infrared spectroelectrochemistry: a study of linear molybdenum/iron/sulfur clusters

The far-infrared spectroelectrochemistry of linear M/Fe/S (M=Mo, W) complexes was investigated in methylene chloride and dichloroethane. With CsI as spectral windows, bands above 200 cm−1 can be observed in methylene chloride, except for a weak methylene chloride band at 450 cm−1. Substitution of dichloroethane for methylene chloride, solvents of nearly identical electrochemical properties, allows one to observe solute bands in the 450-cm−1 region. The far-infrared spectroelectrochemistry of [MoFe2S4Cl4]2− and its tungsten analogue was investigated. The disappearance of the oxidation bands and the appearance of bands due to the reduced product could be clearly observed. The origin of the vibrational bands could be clearly identified using 34S-substituted complexes. In addition to the far-infrared bands, the resonance Raman spectroelectrochemistry of the oxidized and reduced complex, along with the 34S-substituted complexes was obtained. Far-infrared and resonance Raman spectroelectrochemistry can be combined to understand the electrochemical mechanism of transition metal complexes. The far-infrared spectroelectrochemistry of [MoFe2S4Cl4]2− and its tungsten analogue was investigated. The disappearance of the initial bands and the appearance of bands due to the reduced product could be clearly observed. Resonance Raman spectroscopy and the use of 34S-substituted complexes were used for characterization of the reactant and products

Functional interplay between NTP leaving group and base pair recognition during RNA polymerase II nucleotide incorporation revealed by methylene substitution.

RNA polymerase II (pol II) utilizes a complex interaction network to select and incorporate correct nucleoside triphosphate (NTP) substrates with high efficiency and fidelity. Our previous 'synthetic nucleic acid substitution' strategy has been successfully applied in dissecting the function of nucleic acid moieties in pol II transcription. However, how the triphosphate moiety of substrate influences the rate of P-O bond cleavage and formation during nucleotide incorporation is still unclear. Here, by employing β,γ-bridging atom-'substituted' NTPs, we elucidate how the methylene substitution in the pyrophosphate leaving group affects cognate and non-cognate nucleotide incorporation. Intriguingly, the effect of the β,γ-methylene substitution on the non-cognate UTP/dT scaffold (∼3-fold decrease in kpol) is significantly different from that of the cognate ATP/dT scaffold (∼130-fold decrease in kpol). Removal of the wobble hydrogen bonds in U:dT recovers a strong response to methylene substitution of UTP. Our kinetic and modeling studies are consistent with a unique altered transition state for bond formation and cleavage for UTP/dT incorporation compared with ATP/dT incorporation. Collectively, our data reveals the functional interplay between NTP triphosphate moiety and base pair hydrogen bonding recognition during nucleotide incorporation

Investigation of polyviologens as oxygen indicators in food packaging

A triggered oxygen indicator, formulated from a combination of electrochrome, titanium dioxide and EDTA, was evaluated for use in modified atmosphere packaging. Methylene blue was not an ideal electrochrome due to its slow reduction to the leuco form and fast subsequent oxidation by oxygen present at low concentrations, >0.1%. Polyviologen electrochromes showed much faster reduction after exposure to UV light. Thionine and 2,2?-dicyano-1,1?-dimethylviologen dimesylate, which have more anodic reduction potentials compared to methylene blue, can be used to produce oxygen indicators with decreased sensitivity to oxygen. These indicators can be used to detect oxygen even when levels increase up to 4.0%

Biosynthesis of the protoberberine alkaloid jatrorrhizine

Feeding experiments with distant single or doubly labelled precursors show that the methylene dioxy group of berberine is opened in the formation of jatrorrhizine