The ratio of acids

In this study, the extraction of chlorogenic acid from Vietnamese green coffee beans was optimized using the response surface methodology. A second-order polynomial model with three important variables (liquid-to-solid ratio, temperature, and extraction time) was used.

11p vibecca 01-10-2024 1 1   Download

In this study, nano Fe2O3 particles were synthesized by the combustion of gel from polyvinyl acohol (PVA) and tartaric acid (TA) for the degradation of methyl blue (MB) from the aqueous solution by the photocatalytic process. Factors affecting on Fe2O3 formation such as the pH of solution, temperature of gel formation, mole ratio of TA/PVA, temperature of calcination were investigated.

5p vikwong 29-09-2024 6 1   Download

In this study, the photocatalytic degradation of rhodamine b (RhB) is investigated over metal-organic framework materials based on bismuth and trimesic acid (Bi-BTC) with different metal-to-ligand molar ratios. All obtained products are characterized by using powder X-ray diffraction, scanning electron microscopy, and UV–vis diffuse reflectance spectroscopy.

6p vikwong 29-09-2024 1 1   Download

Two ionic liquids named triethyl ammonium oleate ([TEA][Oleate] and triethyl ammonium stearate ([TEA][Stearate]) were synthesized from triethyl amine and oleic/stearic acids in water and in ethanol solvents. The synthesized ionic liquids were characterized by FT-IR and NMR spectra to confirm their structure. The influence of some parameters such as structure of ionic liquid anion, solvent, reaction time, reaction temperature, and acid/amine molar ratio on the synthesis processes of triethyl ammonium oleate and triethyl ammonium stearate was investigated.

6p vikwong 29-09-2024 3 1   Download

From the ethanol extract of dried powders of Andrographis paniculata Nees leaves growing in Hung Yen Province, five compounds were isolated and identified: Andrographolide, dodecahexanoic acid, B-sitosterol, a mixture of 14-deoxy-11,12-didehydroandrographolide and 14-deoxyandrographolide (in ratio of 11:5).

7p tamynhan5 10-12-2020 8 2   Download

The present investigation was therefore undertaken to examine the effect of storage conditions (time, temperature and packaging material) of self rising flour containing different leavening agents with acid calcium phosphate on the quality characteristics of cookies, muffins and cakes and microbiological quality of self rising flour during storage.

14p kequaidan7 01-09-2020 24 2   Download

The application of the normal hydrothermal and microwave hydrothermal process to recover the total oxides of the rare earths from monazite in Quang Nam by acids HCl, HNO3, H2SO4 and alkali NaOH have been studied. Research results show that the best conditions to obtain the total rare earth oxide in Quang Nam and with the highest performance microwave hydrothermal metallurgy ore monazite in Quang Nam particle size < 0,076mm in the rate of 12M H2SO4 /ore is 5:1 (ml/g) in 60 minutes in the microwave power 450W.

6p thiendiadaodien_9 04-03-2019 22 0   Download

The results showed that the exchange efficiency was high for both rubidium and cesium. The exchange efficiency ratios depended on the kind of inorganic compound and acid concentration.

9p bautroibinhyen17 13-02-2017 31 3   Download

The basic properties of zeolites were studied by using quantum-chemical calculations. The obtained results have demonstrated that the basicity of zeolites in the forms of alkali cations (Li, Na or K) is increased with increasing cation radius. While the Si/Al ratio in the framework increases, the basicity of zeolites decreases. The application of adsorption method using acidic gases (CO2) for determining basicity may be suitable for solid bases without exhanged ion, but not for zeolites.

6p uocvong04 24-09-2015 66 3   Download

Grafting acrylic acid (AA) onto linear, low density polyethylene (LLDPE) is carried out in melt state in the presence of styren (St). The effects of reaction time and temperature; concentrations of initiator and St; mixing speed of LLDPE and chemicals on the grafting degree of AA onto LLDPE is estimated. St is added to try to decrease the extent of crosslinking reaction and to increase the grafting degree of AA on to LLDPE. The obtained results show that the suitable conditions for the mentioned process above are 2 wt% of AA; 0.3 wt% of DCP; molar ratio of St/AA of 2.

5p uocvong03 24-09-2015 60 4   Download

The epoxy ester was prepared from epoxy resin DER 331 and fatty acid by esterification reaction in inert gas without catalyst. The kinetics of the esterification was investigated and the results shown that the temperature, reaction time and mol ratio of epoxy resin to fatty acid suitable to electro-deposition process are 220o C, 150 minutes and 1/4, respectively. The received epoxy ester was modified with 15% (wt%) maleic anhydride at 175o C for 120 min which was adapt to binder for anodic electro-deposition coating.

5p uocvong03 24-09-2015 51 5   Download

The technological conditions of obtaining the polylactic acid-Vietnamese cassava starch blend on the mix-brabender were investigated. The optimal conditions were: temperature 160o C, reaction time 6 minutes, screw speed 45 r/min., initial material ratio in weight percentage PLA80- PEG10-TB20. Polyethyleneglycol (PEG) as a plasticizer, PN-47 as a distribution agent was used. It showed that the optimal starch content was 20 wt%. Increase in starch content lead to increase in water absorbability and weight loss of the materials.

7p uocvong01 24-09-2015 76 9   Download

As an adaptation process to the growth retardation provoked by the presence of nonlethal concentrations of ergosterol biosynthesis inhibitors, Ustilago maydis alters the ratio of linoleic to oleic acid bound to plasma membrane ´ complex lipids [Hernandez, A., Cooke, D.T., Lewis, M. & Clarkson, D.T. (1997) Microbiology 143, 3165–3174]. This alteration increases plasma membrane H+-ATPase hydrolytic activity.

6p research12 01-06-2013 38 4   Download

The structure of post-translational modifications of human heparin cofactor II isolated from human serum and from recombinant Chinese hamster ovary cells and their effects on heparin binding have been characterized. Oligosaccharide chains were found attached to all three potential N-glycosylation sites in both protein preparations. The carbohydrate structures of heparin cofactor II circulating in blood are complex-type diantennary and triantennary chains in a ratio of 6 : 1 with the galactose being 90% sialylated with a2 fi 6 linked N-acetylneuraminic acid....

12p research12 01-06-2013 44 3   Download

d-Aminolevulinic acid (ALA), which is an intermediate in the biosynthesis of chlorophyll a, can be biosynthesized via theC5pathway and the Sheminpathway inEuglena gracilis. Analysis of the 13 C-NMR spectrum of 13 C-labeled methyl pheophorbidea, derived from 13 C-labeled chlorophylla biosynthesized fromD-[1-13 C]glucose byE. gracilis,provid-ed evidence suggesting that ALA incorporated in the 13 C-labeled chlorophyllawas synthesized via both the C5 pathway and the Shemin pathway in a ratio of between 1.5 and 1.7 to one....

7p research12 29-04-2013 29 3   Download

The exopolysaccharide produced byStreptococcus thermo-philus8S in reconstituted skimmed milk is a heteropolysac-charide containing D-galactose, D-glucose, D-ribose, and N-acetyl-D-galactosamine in a molar ratio of 2:1:1:1. Furthermore, the polysaccharide contains one equivalent of a novel open chain nononic acid constituent, 3,9-dideoxy-D-threo-D-altro-nononic acid, ether-linked viaC-2 toC-6 of an additionalD-glucose per repeating unit.

9p tumor12 22-04-2013 32 2   Download

Anumber of cellular systems cooperate in redox regulation, providing metabolic responses according to changes in the oxidation (or reduction)of the redox active components of a cell. Key systems of central metabolism, such as the 2-oxo acid dehydrogenase complexes, are important participants in redox regulation, because their function is controlled by the NADH/NAD + ratio and the complex-bound dihydro-lipoate/lipoate ratio.

7p tumor12 20-04-2013 37 4   Download

The O-specific polysaccharide ofCitrobacter braakiiPCM 1531 (serogroupO6) was isolated bymild acid hydrolysis of the lipopolysaccharide (LPS) and found to containD-fucose, L-rhamnose, 4-deoxy-D-arabino-hexose andO-acetyl groups in molar ratios 2 : 1 : 1 : 1. On the basis of methylation analysis and 1 Hand13 C NMR spectroscopy data, the structure of the branched tetrasaccharide repeating unit of theO-specific polysaccharidewas established.

7p fptmusic 16-04-2013 51 4   Download

The core structure of the lipopolysaccharide (LPS) isolated from a rough strain of the phytopathogenic bacterium Pseudomonas syringaepv.phaseolicola, GSPB 711, was investigated by sugar and methylation analyses, Fourier transform ion-cyclotron resonance ESI MS, and one- and two-dimensional 1 H-, 13 C- and 31 P-NMR spectroscopy. Strong alkaline deacylation of the LPS resulted in two core-lipid A backbone undecasaccharide pentakisphos-phates in the ratio
2.

0p awards 05-04-2013 38 2   Download

The properties of theD6 desaturase/acetylenase from the mossCeratodon purpureusand theD12 acetylenase from the dicotCrepis alpinawere studied by expressing the encoding genes inArabidopsis thalianaandSaccharomyces cerevisiae. The acetylenase fromC. alpinaD12 desaturated both oleate and linoleate with about equal efficiency. The desaturation of oleate gave rise to 9(Z),12(E)- and 9(Z),12(Z)-octadeca-dienoates in a ratio of approximately 3 : 1.

0p awards 05-04-2013 41 3   Download