PHYSICAL AND CHEMICAL PROPERTIES OF GLUTEN I. ESTIMATION OF MOLECULAR PROPERTIES USING ELECTROPHORETIC AND DIFFUSION DATA

1949 ◽  
Vol 27c (3) ◽  
pp. 103-124 ◽  
Author(s):  
J. R. Colvin ◽  
A. G. McCalla
Keyword(s):  
Isoelectric Point ◽  
Sodium Salicylate ◽  
Selective Adsorption ◽  
High Surface ◽  
Chemical Properties ◽  
Protein Molecule ◽  
Molecular Characteristics ◽  
Mean Values ◽  
Degree Of Hydration ◽  
Dispersing Agent

The molecular characteristics of gluten in sodium salicylate solutions have been studied by means of diffusion and electrophoretic techniques. The results of the observations indicate that gluten in sodium salicylate is electrostatically homogeneous with a high mean negative valence of 34 and therefore a high surface charge density. The isoelectric point of gluten in this dispersing agent is below pH 4.0. This low value of the isoelectric point and the high valence of the protein molecule is probably due to selective adsorption of salicylate ions on gluten. The particles in the fraction of gluten molecularly dispersed in 0 5 μ sodium salicylate are prolate ellipsoids of revolution of the order of 25 Å in diameter and 400 to 450 Å long. These are mean values as the molecularly dispersed particles are not uniform in mass. When they are aggregated it is side by side association rather than end to end. The density of dehydrated gluten is 1.291 gm. per cc. Qualitative evidence is given for the view that the degree of hydration of gluten particles is probably not great.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

scholarly journals Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1026 ◽  
Author(s):  
Laís G. Fregolente ◽  
João Vitor dos Santos ◽  
Giovanni Vinci ◽  
Alessandro Piccolo ◽  
Altair B. Moreira ◽  
...  
Keyword(s):  
Plant Growth ◽  
Phosphoric Acid ◽  
13C Nmr ◽  
Chemical Properties ◽  
Water Soluble ◽  
Molecular Characteristics ◽  
Initial Growth ◽  
Growth Promoters ◽  
Molecular Features ◽  
Potential Use

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.

ULTRACENTRIFUGE AND DIFFUSION STUDIES ON GLUTEN

1942 ◽  
Vol 20c (3) ◽  
pp. 130-159 ◽  
Author(s):  
A. G. McCalla ◽  
Nils Gralén
Keyword(s):  
Sodium Salicylate ◽  
Minimum Weight ◽  
Average Molecular Weight ◽  
Sedimentation Equilibrium ◽  
Velocity Sedimentation ◽  
Molecular Characteristics ◽  
Weight Average Molecular Weight ◽  
Diffusion Constants ◽  
Diffusion Studies ◽  
And Diffusion

The molecular characteristics of gluten in sodium salicylate solutions were studied by means of sedimentation velocity, sedimentation equilibrium, and diffusion measurements. The proportion of total gluten protein molecularly dispersed increased with increase in concentration of sodium salicylate up to 12%, but the dispersed portions had essentially the same sedimentation constant (2.5 ± 0.15) regardless of the concentration of the dispersing medium.The most soluble 25 per cent of the gluten was all molecularly dispersed, but was definitely inhomogeneous. The weight-average molecular weight of this fraction was 44,000, but there is reason to believe the minimum weight may be about 35,000. None of the other fractions was entirely molecularly dispersed, the proportion decreasing with decreasing solubility of the fractions. Aggregates of many sizes existed in all of these fractions, but only the most insoluble contained aggregates large enough to cause opacity. Sedimentation constants of the molecularly dispersed portions increased slightly with decreasing solubility, while diffusion constants decreased markedly. None of the fractions yielded normal curves (diffusion diagrams) but the more soluble the fraction, the more nearly normal the curve. The inhomogeneity responsible for the varying rates of diffusion was due partly to differences in proportion and properties of the molecularly dispersed gluten and partly to aggregates.All properties showed progressive changes both within and between the arbitrarily produced fractions. These results, therefore, support the hypothesis that gluten is a protein system showing progressive and regular changes in properties with change in solubility.

Recent trends in carbon nanotubes based prostate cancer therapy: A biomedical hybrid for diagnosis and treatment

2021 ◽  
Vol 18 ◽  
Author(s):  
Raja Murugesan ◽  
Sureshkumar Raman
Keyword(s):  
Prostate Cancer ◽  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Drug Loading ◽  
High Surface ◽  
High Surface Area ◽  
High Capacity ◽  
Chemical Properties ◽  
Diagnosis And Treatment ◽  
High Level

: At present treatment methods for cancer are limited, partially due to the solubility, poor cellular distribution of drug molecules and, the incapability of drugs to annoy the cellular barriers. Carbon nanotubes (CNTs) generally have excellent physio-chemical properties, which include high-level penetration into the cell membrane, high surface area and high capacity of drug loading by in circulating modification with bio-molecules, project them as an appropriate candidate to diagnose and deliver drugs to prostate cancer (PCa). Additionally, the chemically modified CNTs which have excellent 'Biosensing' properties therefore makes it easy for detecting PCa without fluorescent agent and thus targets the particular site of PCa and also, Drug delivery can accomplish a high efficacy, enhanced permeability with less toxic effects. While CNTs have been mainly engaged in cancer treatment, a few studies are focussed on the diagnosis and treatment of PCa. Here, we detailly reviewed the current progress of the CNTs based diagnosis and targeted drug delivery system for managing and curing PCa.

scholarly journals Atomically Dispersed M-N-C Catalysts in Proton Exchange Membrane Fuel Cells: Recent Progress and Perspectives

2021 ◽  
Vol 308 ◽  
pp. 01019
Author(s):  
Haoran Kong ◽  
Jiarong Liu ◽  
Yu Yue
Keyword(s):  
Fuel Cells ◽  
Cost Effectiveness ◽  
Proton Exchange Membrane ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Proton Exchange ◽  
Synthesis Methods ◽  
Zeolitic Imidazolate Framework ◽  
Exchange Membrane

The selection of oxygen reduction reaction (ORR) catalysts plays a key role in enhancing the performance of proton exchange membrane fuel cells (PEMFCs). To optimize the energy conversion technology in PEMFCs and improve the cost-effectiveness of ORR catalysts, atomically dispersed metal-nitrogen-carbon (M-N-C) catalyst is regarded as one of the most promising materials to replace Pt-based catalysts. In this review, we summarize the advantages of atomically dispersed M-N-C catalysts in both physical and chemical properties, including controllable dimensions, ease of accessibility, high surface area and excellent conductivity. Additionally, the unique merits of their cost-effectiveness are also described by a concise comparison with other ORR catalysts. Subsequently, some of its main synthesis methods are based on the most commonly used zeolitic imidazolate framework (ZIF) precursor. Several other precursors involve carbon, nitrogen, and one or more active transition metals (mainly iron or cobalt) are introduced briefly. Although there are a variety of synthesis methods, all these methods are in line with pyrolysis technology. Then, the recent advancements of atomically dispersed M-N-C catalysts related to their development and application of Fe-N-C, Mn-N-C, and Co-N-C catalysts are comprehensively described. Finally, based on some common M-N-C catalysts, many improvement ideas are also proposed. The focus is on how to control the negative reaction in Fe-N-C catalysts, improve the activity of Co-N-C catalysts and Mn-N-C catalysts, and find more suitable transition metal materials to prepare M-N-C catalysts.

Changes in Soil Chemical Properties Under Different Land-Use Systems and Soil Depth Layers: A Case Study from the Central Highlands of Ethiopia

2020 ◽  
Author(s):  
Yadesa Bato ◽  
Tamrat Bekele ◽  
Sebsebe Demissew
Keyword(s):  
Land Use ◽  
Soil Ph ◽  
Eucalyptus Globulus ◽  
Soil Depth ◽  
Chemical Properties ◽  
Natural Forest ◽  
Soil Chemical Properties ◽  
Plantation Forest ◽  
Mean Values ◽  
Land Use Systems

Abstract Background: Soil chemical properties have changed under different land-use systems and soil depth layers either by increasing or decreasing. Hence, scientifically information on the soil chemical properties dynamics under different land-use systems and soil depths are crucial for best land management practices, and to avoiding ecological negative impacts of it for sustainable development. The study aimed to evaluate the soil chemical properties dynamics under different land-use systems and soil depths in the central highlands of Ethiopia. The land-use systems included natural forest, four exotic tree plantation species (Eucalyptus globules, Cupressus lusitanica, Grevillea robusta, and Pinus patula), grassland, grazing land, and cropland. Results: The analysis of variance (ANOVA) for the majority of soil chemical properties of OC, TN, Avial. P, soil pH, EC, CEC, and exchangeable bases (Ca, Mg, K, Na) were showed that significant variations among land-use systems (P<0.0001). The highest mean values of OC (3.49 % DM ), TN ( 0.31 % DM) , Avail.P (31.52 mg/kg of soil ), CEC ( 33.63 meq/100gm soil), Exch. Ca (17.13 cmol(+)/kg soil), Exch. Mg (5.37 cmol(+)/kg soil), and Exch. K ( 3.60 cmol(+)/kg soil) were observed under natural forest than others of land-use systems. The results also showed that the lowest mean values of OC (1.47 % DM), TN (0.13 %DM), soil pH (5.38), CEC (18.98 meq/100gm soil), Exch. Ca (9.93 cmol(+)/kg soil), Exch. K (1.20 cmol(+)/kg soil), and Exch. Na (0.22 cmol(+)/kg soil) were recorded under cropland than other land-use systems. The highest mean values of EC (3.47ds/m), and Exch. Na (0.60 cmol(+)/kg soil) were observed under Eucalyptus globulus plantation forest. The overall mean values of OC, TN, Avail.P, CEC, Exch. Mg, Exch. Ca, Exch. K, and Exch. Na accumulation at the topsoil layer was higher than that of the subsoil layer except for soil pH and EC. Conclusion: In general, the majority of soil chemical properties under cropland and Eucalyptus globulus plantation forest were poorer than the soils subjected to other land-use systems which indicated that changes in land use systems were significantly affected soil chemical properties.

scholarly journals Effective sericin-fibroin separation from Bombyx mori silkworms fibers and low-cost salt removal from fibroin solution

2019 ◽  
pp. 97-101
Author(s):  
Estefanía Echeverri-Correa ◽  
David Orlando Grajales-Lopera ◽  
Santiago Gutiérrez-Restrepo ◽  
Claudia Patricia Ossa-Orozco
Keyword(s):  
Bombyx Mori ◽  
Sodium Carbonate ◽  
Textile Industry ◽  
Sodium Carbonate Solution ◽  
Low Cost ◽  
High Surface ◽  
Chemical Properties ◽  
Surface Reactivity ◽  
Carbonate Solution ◽  
Cellulose Membrane

Silk from Bombyx mori has two main proteins: fibroin and sericin. Fibroin is a protein that exhibits good biocompatibility and high surface reactivity, desirable properties for many biomedical applications. Sericin is related with adverse immune response in some medical uses. Therefore, its removal (degumming) is desirable in almost all fields, including the textile industry and biological applications. In this study, three degumming methods (distilled water, liquid neutral detergent and sodium carbonate solution) were evaluated using Raman spectroscopy. Degummed silk treated with sodium carbonate solution exhibits a pattern consistent with previous studies for sericin-free fibroin, and significant differences with the untreated silk pattern. Also, degummed fibroin fibers were dissolved in a calcium chloride solution, in pursuit of a more versatile material. Additionally, different porous membranes of dialysis tubes were tested to remove residual salts, and were compared by conductivity measurements and EDS analysis, identifying good performance for an affordable food cellulose membrane. The results showed that it is possible to obtain fibroin with adequate chemical properties, using low-cost process and membrane of dialysis tubes. 

scholarly journals Nano metal fluorides: small particles with great properties

ChemTexts ◽  
2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Erhard Kemnitz ◽  
Stefan Mahn ◽  
Thoralf Krahl
Keyword(s):  
Surface Area ◽  
State Of The Art ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Chemical Properties ◽  
Lewis Acidity ◽  
Small Particles ◽  
Specific Chemical ◽  
Metal Fluorides

Abstract The recently developed fluorolytic sol–gel route to metal fluorides opens a very broad range of both scientific and technical applications of the accessible high surface area metal fluorides, many of which have already been applied or tested. Specific chemical properties such as high Lewis acidity and physical properties such as high surface area, mesoporosity and nanosize as well as the possibility to apply metal fluorides on surfaces via a non-aqueous sol make the fluorolytic synthesis route a very versatile one. The scope of its scientific and technical use and the state of the art are presented.

scholarly journals Fast coalescence of metallic glass nanoparticles

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuan Tian ◽  
Wei Jiao ◽  
Pan Liu ◽  
Shuangxi Song ◽  
Zhen Lu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Ostwald Ripening ◽  
Kinetic Monte Carlo ◽  
High Surface ◽  
Chemical Properties ◽  
Supercooled Liquid ◽  
Atomic Scale ◽  
Surface Mobility ◽  
Coarsening Kinetics ◽  
Amorphous Nanoparticles

AbstractThe coarsening of crystalline nanoparticles, driven by reduction of surface energy, is the main factor behind the degeneration of their physical and chemical properties. The kinetic phenomenon has been well described by various models, such as Ostwald ripening and coalescence. However, the coarsening mechanisms of metallic glass nanoparticles (MGNs) remains largely unknown. Here we report atomic-scale observations on the coarsening kinetics of MGNs at high temperatures by in situ heating high-resolution transmission electron microscopy. The coarsening of the amorphous nanoparticles takes place by fast coalescence which is dominated by facet-free surface diffusion at a lower onset temperature. Atomic-scale observations and kinetic Monte Carlo simulations suggest that the high surface mobility and the structural isotropy of MGNs, originating from the disordered structure and unique supercooled liquid state, promote the fast coalescence of the amorphous nanoparticles at relatively lower temperatures.

Effects of AgNO3 Concentration on the Preparation of Nano-Silver

2011 ◽  
Vol 412 ◽  
pp. 239-242
Author(s):  
Feng Rui Zhai ◽  
Zhong Zhou Yi ◽  
Hong Wei Zhang
Keyword(s):  
Raw Materials ◽  
Chemical Reduction ◽  
High Surface ◽  
Protective Agent ◽  
Test Results ◽  
Reaction Conditions ◽  
Dispersing Agent ◽  
Crystal Properties ◽  
High Surface Activity ◽  
Wide Usage

nanosilver powder has high surface activity, catalysis property and wide usage, so it is important to study its preparation method. In this paper, nanosilver powder was prepared with industrial AgNO3 as raw materials, hydrazine hydrate as the reducing agent, polyvinylpyrrolidone (PVP) as the polymeric protective agent, polyethylene glycol as the dispersing agent by solution chemical reduction method. The effects of AgNO3 concentration on the preparation of nanosilver were studied, and the final product was examined with TEM testing. The test results show that it can be obtained flake nanosilver with good performance by controlling the reaction conditions, such as dispersion, stability and crystal properties.

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