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 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.

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.

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.

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.

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.

Dr Brian Gibberd (1931–2006): a pioneering clinician in Refsum's disease

2007 ◽  
Vol 35 (5) ◽  
pp. 862-864
Author(s):  
A.S. Wierzbicki ◽  
M.D. Lloyd
Keyword(s):  
Phytanic Acid ◽  
Clinical Medicine ◽  
Neurological Diseases ◽  
Collaborative Study ◽  
Chain Structure ◽  
Peroxisomal Disorders ◽  
Human Diet ◽  
Branched Chain Fatty Acids ◽  
Branched Chain ◽  
Work Done

Branched-chain fatty acids are common components of the human diet (phytanic acid) or are produced endogenously (bile acids), and are also used as medicines (ibuprofen). Owing to their branched-chain structure, they are metabolized in peroxisomes. In the case of phytanic acid, the presence of a 3-methyl group prevents β-oxidation, and instead it undergoes one round of α-oxidation to allow further metabolism. Defects in this process give rise to neurological diseases and cancer. Dr Brian F. Gibberd was one of the first U.K. physicians to recognize the importance of these peroxisomal metabolic pathways in clinical medicine, and pioneered their study. This obituary recognizes his many achievements in neurology and especially in the treatment of peroxisomal disorders. The following four papers from this mini-symposium entitled ‘Advances in peroxisomal α-, β- and ω-oxidation’ describe work done in this area as part of a collaborative study in which Dr Gibberd played a key role. This work was presented as part of the Cardiovascular Bioscience focused topic at the Life Sciences 2007 conference, and this mini-symposium was dedicated to Dr Gibberd and his important contributions to this field.

UNIVERSAL SCALING BEHAVIOR OF THE TACKINESS OF POLYMER MELTS

2019 ◽  
Vol 92 (4) ◽  
pp. 625-638
Author(s):  
You Wang ◽  
Aiping Zhou ◽  
Xiaorong Wang
Keyword(s):  
Surface Preparation ◽  
Polymer Melt ◽  
Chain Structure ◽  
Time Profile ◽  
Scaling Behavior ◽  
Universal Scaling ◽  
Molecular Weights ◽  
Scaling Relationships ◽  
Branched Chain ◽  
Force Time

ABSTRACT Tack properties of nine linear polyisoprenes (PIPs) with molecular weights ranging from 84 to 476 kg/mol and two star-branched PIPs with molecular weights ranging from 609 to 1130 kg/mol were investigated on various surfaces, such as stainless steel, aluminum, copper, quartz, and plastics. In the investigation, a finger-sized cylindrical rod having a flat end face was brought into contact with a PIP polymer. After equilibrium was reached, the cylindrical rod was removed from the substrate at a constant pull-off velocity, Vs. We found that when the pulling speed (Vs) is greater than a critical speed (Vc), the maximum tack force (Fmax) can be generally described by the following scaling relationships: Fmax ∼ Vs1/3 and Fmax ∼ tmax−1/2, where tmax is the time when the maximum force is reached in the force–time profile. Remarkably, this scaling behavior of the tackiness appears to be universal, as it is independent of the adhered surface preparation, the molecular weight distribution, and the linear or branched chain structure of a polymer melt.

Direct Observation of Monolayer Zones in Al-wt 4% Cu

1990 ◽  
Vol 48 (1) ◽  
pp. 14-15
Author(s):  
B. Jouffrey ◽  
D. Dorignac ◽  
A. Bourret
Keyword(s):  
Solid Solution ◽  
Synchrotron Radiation ◽  
Direct Observation ◽  
Supersaturated Solid Solution ◽  
Original Model ◽  
X Ray ◽  
Image Position

Since the early works on GP zones and the model independently proposed by Preston and Guinier on the first steps of precipitation in supersaturated solid solution of aluminium containing a few percent of copper, many works have been performed to understand the structure of different stages in the sequence of precipitation.The scheme which is generally admitted can be drawn from a work by Phillips.In their original model Guinier and Preston analysed a GP zone as composed of a single (100) copperrich plane surrounded by aluminum atomic planes with a slightly shorter distance from the original plane than in the solid solution.From X-ray measurements it has also been shown that GP1 zones were not only copper monolayer zones. They could be up to a few atomic planes thick. Different models were proposed by Guinier, Gerold, Toman. Using synchrotron radiation, proposals have been recently made.

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