STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: LXI. PROPERTIES OF THE FRACTIONATED NITRATES OF TWO FRACTIONS OF CORN STARCH

1946 ◽  
Vol 24b (5) ◽  
pp. 246-253 ◽  
Author(s):  
W. R. Ashford ◽  
T. H. Evans ◽  
Harold Hibbert
Keyword(s):  
Relative Stability ◽  
Corn Starch ◽  
Chain Structure ◽  
Linear Type ◽  
Relative Stabilities ◽  
Preferential Adsorption ◽  
Chain Fraction ◽  
Branched Chain ◽  
Nitrogen Contents

Corn starch has been separated into two individual components, arbitrarily designated as amylose (linear fraction) and amylopectin (branched-chain fraction) by means of preferential adsorption on cellulose (Tanret–Pacsu method). These components have been nitrated and their nitrates fractionated by dissolution in ethanol. The relative stabilities and nitrogen contents of the nitrated fractions have been studied.Unfractionated amylose nitrate has greater stability than unfractionated amylopectin nitrate as judged by the Bergmann–Junk test. Dissolution methods of fractionation showed a much higher solubility of the amylopectin nitrate, the greater relative stability of the amylose fractions, and the somewhat greater stabilizing action of ethanol in the case of the latter.The widely different solubilities of amylose and amylopectin nitrates in conjunction with the lower ethanol solubility of whole starch nitrate are in accordance with the theory of a branched-chain structure for amylopectin and the linear type for amylose.

scholarly journals Effect of Surfactant Molecular Structure on Emulsion Stability Investigated by Interfacial Dilatational Rheology

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1127
Author(s):  
Yuejie Jin ◽  
Dingrong Liu ◽  
Jinhua Hu
Keyword(s):  
Emulsion Stability ◽  
Chain Structure ◽  
Interfacial Film ◽  
Future Design ◽  
Rheological Method ◽  
Viscoelastic Modulus ◽  
Hydrophobic Chain ◽  
Branched Chain ◽  
The Stability ◽  
Branched Structure

Polyglycerol polyricinolate (PGPR) and polyglycerol-2 dioleate were selected as model surfactants to construct water-in-oil (W/O) emulsions, and the effect of interfacial rheological properties of surfactant film on the stability of emulsions were investigated based on the interfacial dilatational rheological method. The hydrophobicity chain of PGPR is polyricinic acid condensed from ricinic acid, and that of polyglycerol-2 dioleate is oleic acid. Their dynamic interfacial tensions in 15 cycles of interfacial compression-expansion were determined. The interfacial dilatational viscoelasticity was analyzed by amplitude scanning in the range of 1–28% amplitude and frequency sweep in the range of 5–45 mHz under 2% amplitude. It was found that PGPR could quickly reach adsorption equilibrium and form interfacial film with higher interfacial dilatational viscoelastic modulus to resist the deformation of interfacial film caused by emulsion coalescence, due to its branched chain structure and longer hydrophobic chain, and the emulsion thus presented good stability. However, polyglycerol-2 dioleate with a straight chain structure had lower interfacial tension, and it failed to resist the interfacial disturbance caused by coalescence because of its lower interfacial dilatational viscoelastic modulus, and thus the emulsion was unstable. This study reveals profound understanding of the influence of branched structure of PGPR hydrophobic chain on the interfacial film properties and the emulsion stability, providing experimental reference and theoretical guidance for future design or improvement of surfactant.

In Vitro adsorption Spectrum of Plasma Amino Acids by Coated Charcoal Hemoperfusion

1983 ◽  
Vol 6 (5) ◽  
pp. 267-270 ◽  
Author(s):  
Z.Q. Shi ◽  
T.M.S. Chang
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Hepatic Coma ◽  
Aromatic Amino Acids ◽  
Molar Ratio ◽  
Adsorption Experiment ◽  
Preferential Adsorption ◽  
Branched Chain ◽  
Charcoal Hemoperfusion

In order to clarify wether coated charcoal hemoperfusion is capable of normalizing amino acid disturbances in hepatic coma, in vitro adsorption and in vitro hemoperfusion studies were carried out. We have found that collodion-coated activated charcoal beads preferentially removed much more aromatic acids (AAA) than branched chain amino acids (BCAA). In the in vitro adsorption experiment with 50 μM amino acid standards aqueous solution, 99% of AAAs were removed by charcoal while only 50 to 81% of BCAAs were removed. As the concentration of amino acids in solution was doubled from μM to 100 μM, BCAA removal was halved while about 90% of AAA was still being removed. In vitro hemoperfusion with heparinized blood from hepatic failure rats, the clearance and the removal of AAAs were significantly greater than those of BCAAs. Consequently, the molar ratio of BCAA over AAA was markedly improved from the initial 1.09 to 3.87 after 60 min of hemoperfusion. Thus, we have demonstrated the preferential adsorption of aromatic amino acids by collodion-coated charcoal beads. The correction of BCAA/AAA molar ratio is also demonstrated.

Dodecahedron- and Bowl-Shaped Structures C20

1992 ◽  
Vol 270 ◽  
Author(s):  
Zdenék Slanina ◽  
Ludwik Adamowicz
Keyword(s):  
High Temperature ◽  
Temperature Region ◽  
Relative Stability ◽  
Three Dimensional ◽  
Two Dimensional ◽  
High Temperature Region ◽  
Relative Stabilities ◽  
One Dimensional ◽  
Very High ◽  
Quantumchemical Method

ABSTRACTPurely carbonaceous aggregates C20 have been studied by the AM1 quantumchemical method. In addition to one dodecahedron-shaped structure possessing C1 symmetry another three-dimensional species is revealed, viz. a bowl-shaped structureof C5v symmetry (and also one two-dimensional and two one-dimensional species). Temperature dependence of the relative stabilities of both three-dimensional structures is evaluated, showing that in the relevant temperature region the fullerenic species is prevailing. However, in a very high temperature region a relative-stability interchange has been predicted.

Chemiluminescence parameters of peroxynitrous acid in the presence of short-chain alcohols and Ru(bpy)32+

2011 ◽  
Vol 65 (6) ◽  
Author(s):  
Lijun Wei ◽  
Huifen Xia ◽  
Zhaopin Wang ◽  
Ping Yuan ◽  
Tong Zhou ◽  
...  
Keyword(s):  
Excited State ◽  
Carbon Chain ◽  
Chain Structure ◽  
Short Chain ◽  
Peroxynitrous Acid ◽  
Optimum Conditions ◽  
Chemiluminescence Intensity ◽  
Branched Chain

AbstractThe chemiluminescence behaviour and mechanism of peroxynitrous acid and Ru(bpy)32+ were studied in the presence of short-chain alcohols (methanol, ethanol, propan-1-ol, propan-2-ol, butanol, 2-methylpropan-1-ol, pentanol). It was found that the chemiluminescence intensity of peroxynitrous acid and Ru(bpy)32+ system could be significantly enhanced by these seven short-chain alcohols. The maximum chemiluminescence wavelength of 608 nm of [Ru(bpy)32+]* in the excited state was attributed to the reaction between Ru(bpy)32+ and dihydroxyalkyl radicals which were generated during the redox course of peroxynitrous acid and alcohols. In addition, the chemiluminescence signals of the system presented depended largely on the solubility and branched-chain structure as well as the length of carbon chain. The analytical characteristics and parameters of the peroxynitrous acid/Ru(bpy)32+/alcohols chemiluminescence system were investigated under optimum conditions.

Relative stability of benziporphyrin and naphthiporphyrin tautomers and the emergence of macrocyclic diatropicity

2014 ◽  
Vol 12 (43) ◽  
pp. 8719-8736 ◽  
Author(s):  
Deyaa I. AbuSalim ◽  
Timothy D. Lash
Keyword(s):  
Relative Stability ◽  
Relative Stabilities ◽  
Good Agreement

The conformations and relative stabilities of a series of benziporphyrin and naphthiporphyrin tautomers were calculated and the diatropic properties of each of these species were assessed. The results were in good agreement with experimental observations and allow favorable delocalization pathways to be identified.

STRUCTURE OF A HEMICELLULOSE FROM MAPLE WOOD PREVIOUSLY EXTRACTED BY LIQUID AMMONIA

1957 ◽  
Vol 35 (4) ◽  
pp. 388-396 ◽  
Author(s):  
L. G. Neubauer ◽  
C. B. Purves
Keyword(s):  
Liquid Ammonia ◽  
Chain Structure ◽  
Hot Water ◽  
Wood Meal ◽  
Branched Chain ◽  
Conventional Study ◽  
Pectic Material

The extraction of maple wood meal with anhydrous liquid ammonia under pressure near 20° altered the wood in such a way that an additional small amount of lignin could be extracted with ethanol, and 1.9% of crude hemicelluloses with hot water. An additional 0.25% of nitrogen was retained, apparently as insoluble amides, by the residual wood. After elimination of pectic material by acetylation, the three subtractions of the hemicellulose acetate had identical specific rotations of −61 ± 1° in chloroform; all three corresponded in composition to a combination of one methylglucuronic anhydride to six anhydroxylose units. A conventional study by the methylation method suggested that the hemicellulose was a branched-chain structure averaging four anhydroxylose units linked 1—4, with one also substituted in the second position, and another linked 1—3.

Relative stabilities of M/NHC complexes (M = Ni, Pd, Pt) against R–NHC, X–NHC and X–X couplings in M(0)/M(ii) and M(ii)/M(iv) catalytic cycles: a theoretical study

2019 ◽  
Vol 48 (45) ◽  
pp. 17052-17062 ◽  
Author(s):  
Alexander V. Astakhov ◽  
Safarmurod B. Soliev ◽  
Evgeniy G. Gordeev ◽  
Victor M. Chernyshev ◽  
Valentine P. Ananikov
Keyword(s):  
Dft Calculations ◽  
Relative Stability ◽  
Theoretical Study ◽  
Reductive Elimination ◽  
Catalyst Stability ◽  
Relative Stabilities ◽  
Elimination Reactions ◽  
Catalytic Cycles

DFT calculations reveal relative stability of MII/NHC and MIV/NHC complexes of nickel, palladium and platinum against the R–NHC coupling and various reductive elimination reactions that influence catalyst stability/decomposition.

scholarly journals The Long‐Periodic Loop‐Branched Chain Structure of the Oxonitridophosphate La 21 P 40 O 46 N 57 , Elucidated by a Combination of TEM and Microfocused Synchrotron Radiation

2019 ◽  
Vol 25 (63) ◽  
pp. 14382-14387 ◽  
Author(s):  
Markus Nentwig ◽  
Simon D. Kloß ◽  
Lukas Neudert ◽  
Lucien Eisenburger ◽  
Wolfgang Schnick ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Chain Structure ◽  
Branched Chain

scholarly journals Structure revision of disaccharidic conjugates of bilirubin-IX α in human bile and identification of phenylazo derivatives B4, B5, and B6 as 2-, 3- and 4-O-acylglucuronides

1978 ◽  
Vol 175 (3) ◽  
pp. 1095-1101 ◽  
Author(s):  
F Compernolle
Keyword(s):  
Mass Spectrometry ◽  
Glucuronic Acid ◽  
Chain Structure ◽  
Positional Isomers ◽  
Human Bile ◽  
Hexuronic Acid ◽  
Structure Revision ◽  
Branched Chain ◽  
Trimethylsilyl Derivatives

Aniline azopigments B4, B5 and B6, derived from conjugates of bilirubin-IX alpha in human bile, and previously characterized as disaccharidic esters [Kuenzle (1970) Biochem. J. 119, 387-394 and 411-435], were analysed by using t.l.c. and mass spectrometry. The compounds were identified as partially separated mixtures of 2-, 3- and 4-O-acylglucuronide positional isomers. The 1-O-acylglucuronide was not detected in the mixtures and was the only compound hydrolysed with beta-glucuronidase. Further scrutiny of structural assignments made by Kuenzle [(1970) Biochem. J. 119, 411-435] led to identification of the lactone and hexuronic acid derivatives that were obtained from azopigment B5 along with glucuronolactone and glucuronic acid. A branched-chain structure, i.e. 3-C-hydroxy-methyl-D-riburonic acid, was assigned previously, but the derivatives have now been identified as various incompletely silylated forms of glucuronolactone and glucuronic acid. Several trimethylsilyl derivatives glucuronolactone were isolated and characterized by n.m.r. and mass spectrometry.

scholarly journals Recycling of Polypropylene/Polyethylene Blends: Effect of Chain Structure on the Crystallization Behaviors

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1456 ◽  
Author(s):  
Chuanchom Aumnate ◽  
Natalie Rudolph ◽  
Majid Sarmadi
Keyword(s):  
Mechanical Performance ◽  
Crystallization Rate ◽  
Chain Structure ◽  
Polymer Waste ◽  
Polyethylene Blends ◽  
Negative Effect ◽  
Unique Approach ◽  
Sorting Process ◽  
Branched Chain ◽  
Similar Density

The combination of high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP) is frequently found in polymer waste streams. Because of their similar density, they cannot be easily separated from each other in the recycling stream. Blending of PP/ polyethylenes (PEs) in different ratios possibly eliminate the sorting process used in the regular recycling process. PP has fascinating properties such as excellent processability and chemical resistance. However, insufficient flexibility limits its use for specific applications. Blending of PP with relative flexible PEs might improve its flexibility. This is a unique approach for recycling or upcycling, which aims to maintain or improve the properties of recycled materials. The effects of the branched-chain structures of PEs on the crystallization behavior and the related mechanical properties of such blends were investigated. The overall kinetics of crystallization of PP was significantly influenced by the presence of PEs with different branched-chain structures. The presence of LDPE was found to decrease the overall crystallization rate while the addition of HDPE accelerated the crystallization process of the blends. No negative effect on the mechanical performance and the related crystallinity was observed within the studied parameter range.

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