scholarly journals Molecular Parameters and Intrinsic Viscosity of Nettle Seed (Urtica Pilulifera) Gum as a Function of Temperature

2021 ◽  
Author(s):  
Zahra Zamani ◽  
Seyed Mohammad Ali Razavi
Keyword(s):  
Activation Energy ◽  
Intrinsic Viscosity ◽  
Shape Factor ◽  
Master Curve ◽  
Molecular Conformation ◽  
Random Coil ◽  
Chain Flexibility ◽  
B Values ◽  
Ellipsoidal Shape ◽  
Seed Gum

Abstract This research focused to determine some molecular properties of Nettle seed gum (NSG), as one of novel and natural source of hydrocolloids, at various temperatures (10, 25, 40, 55, and 70°C) in the dilute region. The results displayed that among the models studied, the Higiro 2 model with highest R2 and lowest RMSE values was the most proper model for determining the intrinsic viscosity of the NSG. According to this model, the intrinsic viscosity value of NSG was obtained in the range of 0.15–0.21 dl/g. It was also revealed that, as the temperature raised, the intrinsic viscosity of NSG declined. The shape factor of NSG at 40°C was spherical, however, with increasing the temperature from 40°C to 70°C, it was changed to an ellipsoidal shape. Berry number and master curve slope revealed that NSG solution at all temperatures was within the dilute regime and that no molecular entanglements were present. The parameter b values acquired for NSG at the intended temperatures showed that the molecular conformation of NSG was random coil. The activation energy and chain flexibility parameter calculated for NSG at the studied temperatures were 0.488×107 J/kgmol and 587.2, respectively.

scholarly journals Intrinsic Viscosity and Molecular Parameters of Wheat Starch-Cess Seed Gum-Sucrose Mixture

2021 ◽  
Vol 11 (4) ◽  
pp. 12068-12081
Keyword(s):  
Ternary System ◽  
Intrinsic Viscosity ◽  
Shape Factor ◽  
Molecular Conformation ◽  
Critical Concentration ◽  
Wheat Starch ◽  
Random Coil ◽  
Solution Properties ◽  
Cress Seed ◽  
Seed Gum

This study aimed to determine the effect of different substitution levels of cress seed gum (CSG, 0-15%) and sucrose (SUC, 0-10%) on the dilute solution properties of native wheat starch (NWS) in terms of intrinsic viscosity, Huggins constant, power-law model slope, berry number, master curve slope, critical concentration, shape factor, and swollen specific volume. In the presence of CSG, the intrinsic viscosity of NWS increased from 0.686 to 0.760 dl/g, the molecular conformation changed from random coil to rod-like, the specific swollen volume enhanced from 0.27 to 0.32 dl/g and the shape factor altered from spherical to prolate. In contrast, sucrose reduced the intrinsic viscosity of NWS to 0.379 dl/g and the specific swollen volume to 0.15 dl/g, altered the conformation to a more random coil and the shape factor to a more compact sphere. In the ternary system, the parameters were close to those of the starch-gum mixture. It can be concluded that CSG overcame the weakening effect of SUC on the NWS solution properties in the ternary system.

Pasting, rheology, antioxidant and texture profile of gluten free cookies with added seed gum hydrocolloids

2020 ◽  
pp. 108201322098059
Author(s):  
Afshan Mumtaz Hamdani ◽  
Idrees Ahmed Wani ◽  
Naseer Ahmad Bhat
Keyword(s):  
Locust Bean Gum ◽  
Composite Flour ◽  
Gluten Free ◽  
B Values ◽  
Texture Profile ◽  
Spread Ratio ◽  
Antioxidant Profile ◽  
Locust Bean ◽  
Seed Gum ◽  
The Impact

The study was carried out with the aim of developing gluten free cookies using rice-chickpea composite flour. Guar and locust bean gum were added to formulations at two test concentrations (0.5 and 1.0%). To study the impact of these hydrocolloids, pasting and rheometry of dough formulations was carried out. The cookies produced were subjected to colour, spread ratio, hardness and antioxidant analysis. Protein (7.56 g/100g), fat (1.78 g/100g), ash (1.25 g/100g) and carbohydrate (80.41 g/100g) content of composite flour varied significantly (p ≤ 0.05) from both rice and chickpea. Higher viscosity, viscoelasticity and antioxidant profile was shown by dough formulations with added gums. Control cookies prepared without gums showed the L*, a* and b* values of 54.62, 3.81 and 35.97, respectively. With the addition of guar and locust bean gum, colour of the cookies became lighter. Spread ratio and hardness of cookies with added gums was higher.

scholarly journals Cholic Acid-Conjugated Methylcellulose-Polyethylenimine Nano-Aggregates for Drug Delivery Systems

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 459 ◽  
Author(s):  
Taewan Kim ◽  
Jaehong Park ◽  
Tae-il Kim
Keyword(s):  
Drug Delivery ◽  
Cholic Acid ◽  
Drug Delivery Systems ◽  
Molecular Conformation ◽  
Drug Loading ◽  
Cellular Membrane ◽  
Delivery Systems ◽  
Critical Aggregation Concentration ◽  
Random Coil ◽  
Helical Conformation

Cholic acid-conjugated methylcellulose-polyethylenimines (MCPEI-CAs) were synthesized and characterized for drug delivery systems. Their synthesis was confirmed by 1H NMR and FT-IR analysis. Induced circular dichroism result with Congo red showed that methylcellulose (MC) and polyethylenimine-grafted cationic derivative (MC-PEI) would have helical conformation and random coil structure, respectively. It was found that MCPEI-CAs could form positively charged (>30 mV Zeta-potential) and spherical nano-aggregates (~250 nm Z-average size) by hydrophobic interaction of CA moieties. Critical aggregation concentration of MCPEI-CA10 was measured as 7.2 × 10−3 mg/mL. MCPEI-CA10 could encapsulate the anticancer drug doxorubicin (Dox) with 58.0% of drug loading content and 23.2% of drug loading efficiency and its release was facilitated in acidic condition. Cytotoxicity of MCPEI-CAs was increased with the increase of cholic acid (CA) graft degrees, probably due to the cellular membrane disruption by interaction with specific molecular structure of amphiphilic MCPEI-CA nano-aggregates. MCPEI-CA10/Dox nano-aggregates showed concentration-dependent anticancer activity, which could overcome the multidrug resistance of cancer cells. In this work, molecular conformation change of MC derivatives by chemical modification and a potential of MCPEI-CA10/Dox nano-aggregates for drug delivery systems were revealed.

LIGHT-SCATTERING STUDIES ON ALUMINUM DISTEARATE

1958 ◽  
Vol 36 (11) ◽  
pp. 1584-1595 ◽  
Author(s):  
A. E. Leger ◽  
J. C. Hyde ◽  
H. Sheffer
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Intrinsic Viscosity ◽  
Benzene Solution ◽  
Unit Length ◽  
Random Coil ◽  
Linear Molecule ◽  
Radius Of Gyration ◽  
Average Unit ◽  
Scattering Study

A light-scattering study of aluminum distearate in dilute benzene solution suggests that it is a linear molecule of random coil shape. This is further substantiated by intrinsic viscosity – molecular weight data, the constancy of the ratio of the molecular weight to the square of the radius of gyration (Rg), the value of Φ in Flory's intrinsic viscosity – molecular weight relationship, and the close agreement between the theoretical and experimental results found for the unit length of the polymer chain. This average unit length has been calculated to be 4.46 Å.

Study on Thermal Decomposition Kinetics of Nano-Cr(OH)3 Powder

2014 ◽  
Vol 692 ◽  
pp. 377-380 ◽  
Author(s):  
Feng Pan ◽  
Zai Yuan Li ◽  
Chun Ji Li
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Shape Factor ◽  
Decomposition Analysis ◽  
Decomposition Kinetics ◽  
Peak Shape ◽  
Exponential Factor ◽  
Mechanism Function ◽  
Kinetics Of ◽  
Tga Analysis

Abstract. This paper studies on the thermal decomposition analysis kinetics of nanometer powders. The DTA-TG-DTG curves obtain by SDT 2960 Simultaneous DSC-TGA analysis apparatus. Under the condition of N2atmosphere operation and rise temperature velocity was 10°C·min-1. The mechanism function dα/dt=κ(1-α)nis used to calculate the kinetics factors. Reaction progressionnwas obtained by calculation of the kissinger peak shape factor method. The results showed that the apparent activation energy of nano-Ni(OH)2was 254.027 KJ·mol-1, the pre-exponential factor was 3.062×1036, the reaction progression was obtained as 1.560, the kinetic equation is dα/dt=3.062×1036exp(-30554.166/T)(1-α)1.560

Study on Kinetics of Nano-Ni(OH)2 Powder Ethanol Desorption Process

2014 ◽  
Vol 1015 ◽  
pp. 509-512
Author(s):  
Feng Pan ◽  
Zai Yuan Li ◽  
Chun Ji Li
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Shape Factor ◽  
Peak Shape ◽  
Desorption Process ◽  
Exponential Factor ◽  
Mechanism Function ◽  
Thermal Analysis Kinetics ◽  
Kinetics Of ◽  
Tga Analysis

This paper studies on the thermal analysis kinetics of nanometer powders ethanol desorption process.The DTA-TG-DTG curves obtain by SDT 2960 Simultaneous DSC-TGA analysis apparatus. Under the condition of N2atmosphere operation and rise temperature velocity was 10°C·min-1. The mechanism functionis used to calculate the kinetics factors. Reaction progressionnwas obtained by calculation of the kissinger peak shape factor method. The results showed that the apparent activation energy of nano-Ni(OH)2was 73.210 kJ·mol-1, the pre-exponential factor was 2.349×1012, the reaction progression was obtained as 1.2767, the kinetic equation is

scholarly journals The macromolecular properties of blood-group substances. Sedimentation-velocity and viscosity measurements

1967 ◽  
Vol 105 (3) ◽  
pp. 1135-1145 ◽  
Author(s):  
J. M. Creeth ◽  
C. G. Knight
Keyword(s):  
Secondary Structure ◽  
Blood Group ◽  
Sodium Dodecyl Sulphate ◽  
Molecular Conformation ◽  
Sodium Dodecyl ◽  
Sedimentation Coefficient ◽  
Sedimentation Velocity ◽  
Random Coil ◽  
Partial Specific Volume ◽  
Blood Group Substances

1. Sedimentation-velocity, intrinsic-viscosity and partial-specific-volume measurements on a typical blood-group-specific glycoprotein are reported for a range of environmental conditions. 2. The sedimentation coefficients, S, are strongly concentration-dependent, and follow the reciprocal law; the limiting values at 2°, 25° and 45°, after correction to 25°, show slight dependence on temperature. 3. The intrinsic viscosities, [η], at 25° and 45° show more marked temperature-dependence, and correspond to a very asymmetric or very expanded molecular conformation. 4. From the value of the ratio K/[η], where K=S0.d(1/S)/dc, it is concluded that the molecular conformation is roughly spherical; application of the Einstein viscosity equation then suggests an expansion factor of about 60, compatible with a flexible configuration approaching that of a random coil. 5. The sedimentation coefficient is not affected by variation of ionic strength in the range 0·01–0·50, nor by pH in the range 3–10. 6. Sodium dodecyl sulphate at 1·5% produces a small decrease in S; the effect is greater than would be expected from the observed extent of binding, but is too small to correspond to a significant change in secondary structure; the serological activity is unaffected by sodium dodecyl sulphate. 7. All the properties observed indicate the absence of any secondary structure in blood-group substances.

Kinetics of Inverse Emulsion Copolymerization of Dimethyl Diallyl Ammonium Chloride and Acrylamide

2014 ◽  
Vol 989-994 ◽  
pp. 348-351 ◽  
Author(s):  
Xiao Na Wang ◽  
Ren Zhi Zhang ◽  
Ni Sha Jin
Keyword(s):  
Activation Energy ◽  
Intrinsic Viscosity ◽  
Initial Temperature ◽  
Tween 80 ◽  
Polymerization Rate ◽  
Emulsion Copolymerization ◽  
Inverse Emulsion ◽  
Rate Of Polymerization ◽  
Span 80 ◽  
Kinetics Of

Inverse emulsion copolymerization of DMDAAC with AM has been investigated by the dilatometer technique using the mixture of Span-80 and Tween-80 as the composite emulsifier and 2,2’-azobis (2-methylpropionconidine) dihydro chloride as the initiator. In inverse emulsion copolymerization, the influences of the concentrations of monomers, emulsifier and initiator and initial temperature on polymerization rate and the intrinsic viscosity of polymer have been examined. Its kinetics can be expressed as,. The overall activation energy for the rate of polymerization was determined with a dilatometer as 20.33 kJ/mol over the temperature range 35-55°C.

Application of the Master Sintering Curve Theory to Non-Isothermal Sintering of BaTiO3 Ceramics

2005 ◽  
Vol 494 ◽  
pp. 417-422 ◽  
Author(s):  
Maria V. Nikolić ◽  
Vera P. Pavlović ◽  
Vladimir B. Pavlović ◽  
Nebojsa Labus ◽  
B.D. Stojanović
Keyword(s):  
Activation Energy ◽  
Barium Titanate ◽  
Heating Rate ◽  
High Purity ◽  
Master Curve ◽  
Sintering Behavior ◽  
Densification Behavior ◽  
Sintering Process ◽  
Heating Rates ◽  
Temperature Time

In this paper a practical approach to the analysis of sintering of BaTiO3 using the Master Sintering Curve concept has been presented. Non-isothermal sintering of high-purity non-doped BaTiO3 ceramics was monitored using a sensitive dilatometer at three different heating rates (10, 20 and 30 oC/min) up to 1380oC. Densification of BaTiO3 during sintering was analyzed using the Master Curve Sintering Theory. A MSC was defined characterizing the sintering behavior of barium-titanate regardless of the heating rate. Construction of the MSC enabled estimation of the process activation energy. Using defined MSC, densification behavior of BaTiO3 ceramics during sintering can be predicted for arbitrary temperature-time excursions and these predictions can be used in controlling and planning the sintering process of this material.

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