scholarly journals The densities of protein crystals and the hydration of proteins

1936 ◽  
Vol 120 (819) ◽  
pp. 422-446 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Mother Liquor ◽  
Aqueous Media ◽  
High Density ◽  
Protein Crystals ◽  
Organic Liquids ◽  
Present Communication ◽  
Denatured Proteins ◽  
Small Crystals ◽  
The Media

The apparent densities of proteins in aqueous solutions have been studied by a number of investigators, including Chick and Martin (1913), and, more recently, by Svedberg and his colleagues, but comparatively few observations of the densities of protein crystals have been published. Eyer (1932) gave the value 1·315 for insulin, Crowfoot (1935) 1·306; Adair and Adair (1934) found 1·296 for haemoglobin; Bernal and Crowfoot (1934) gave 1·28 for pepsin. The media used for the measurements on pepsin and insulin were not recorded. A method for measuring the densities of small crystals by means of observing their flotation in media of different densities was described by Retgers (1889). The present communication records a modification of his method adapted for the investigation of the density of crystalline and of denatured proteins. The first problem studied was the choice of suitable media. The mixtures of organic liquids which are generally used for density determinations of inorganic crystals are open to objections on the grounds that protein crystals cannot be freed from films of their mother liquor without grave risks of irreversible changes. In working with aqueous media this difficulty need not arise, but the media chosen must fulfil the somewhat exacting requirements of a high density with freedom from the capacity to denature or to dissolve the protein.

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

scholarly journals Nitration of Jharia basin coals, India: a study of structural modifications by XRD and FTIR techniques

2021 ◽  
Author(s):  
Prabal Boral ◽  
Atul K. Varma ◽  
Sudip Maity
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Linear Relationship ◽  
Glacial Acetic Acid ◽  
Vitrinite Reflectance ◽  
Aqueous Media ◽  
Interlayer Spacing ◽  
Acetic Acid Medium ◽  
X Ray ◽  
The Media

AbstractFour coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium. FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550–1490 and 1355–1315 cm−1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

2016 ◽  
Vol 75 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Lucas Meili ◽  
Társila Santos da Silva ◽  
Daniely Carlos Henrique ◽  
João Inácio Soletti ◽  
Sandra Helena Vieira de Carvalho ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Experimental Design ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Fiber Diameter ◽  
Aqueous Media ◽  
Process Efficiency ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.

scholarly journals Recyclable glucose-derived palladium(0) nanoparticles as in situ-formed catalysts for cross-coupling reactions in aqueous media

RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16115-16121 ◽  
Author(s):  
Jason E. Camp ◽  
Jay J. Dunsford ◽  
Oliver S. G. Dacosta ◽  
Rebecca K. Blundell ◽  
James Adams ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Media ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions

Renewable sugar-derived palladium(0) nanoparticles (PdNPs) are effective as in situ formed catalysts for cross-coupling reactions in aqueous solutions.

Degradation of polycyclic aromatic hydrocarbons (PAHs) by a mixed culture and its component pure cultures, obtained from PAH-contaminated soil

1995 ◽  
Vol 41 (6) ◽  
pp. 470-476 ◽  
Author(s):  
D. Trzesicka-Mlynarz ◽  
O. P. Ward
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Mixed Culture ◽  
Aromatic Hydrocarbons ◽  
Aqueous Media ◽  
Water Soluble ◽  
Nitrogen Levels ◽  
Glucose Levels ◽  
Polycyclic Aromatic ◽  
Pure Cultures ◽  
The Media

A mixed culture, isolated from soil contaminated with polycyclic aromatic hydrocarbons (PAHs), grew on and degraded fluoranthene in aqueous media supplemented with glucose, yeast extract, and peptone. Increased complex nitrogen levels in the medium promoted bacterial growth and a greater extent of fluoranthene degradation. Amendment of the media with high glucose levels also diminished specific fluoranthene degradation. The mixed culture was capable of degrading a range of other PAHs, including benzo[a]pyrene, anthracene, phenanthrene, acenaphthene, and fluorene. The mixed culture contained four predominant isolates, all of which were Gram-negative rods, three of which were identified as Pseudomonas putida, Flavobacterium sp., and Pseudomonas aeruginosa. Better degradation of a defined PAH mixture was observed with the mixed culture than with individual isolates. A reconstituted culture, prepared by combining the four individual isolates, manifested a similar PAH biodegradation performance to the original mixed culture. When compared with the mixed culture, individual isolates exhibited a relatively good capacity to remove more water-soluble PAHs (acenaphthene, fluorene, phenanthrene, fluoranthene). In contrast, removal of less water-soluble PAHs (anthracene and pyrene) was low or negligible with isolated cultures compared with the mixed culture.Key words: polycyclic aromatic hydrocarbons, mixed culture, fluoranthene, Pseudomonas, Flavobacterium.

Kinetic and spectroscopic studies on the chiral self-aggregation of amphiphilic zinc and copper (l)-prolinate-tetraarylporphyrin derivatives in different aqueous media

2019 ◽  
Vol 17 (5) ◽  
pp. 1113-1120 ◽  
Author(s):  
Fabrizio Caroleo ◽  
Manuela Stefanelli ◽  
Gabriele Magna ◽  
Mariano Venanzi ◽  
Roberto Paolesse ◽  
...  
Keyword(s):  
Metal Ion ◽  
Aqueous Media ◽  
Spectroscopic Studies ◽  
Porphyrin Derivatives ◽  
The Media ◽  
Self Aggregation

The chiral self-aggregation of (l)-proline porphyrin derivatives depends on both the nature of the media and the coordinated metal ion.

Effects of Freezing on Nitrite Stability in Aqueous Solutions

1987 ◽  
Vol 70 (1) ◽  
pp. 22-23
Author(s):  
Paul Muneta ◽  
Richard Jasman ◽  
Luanne M Reid
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Media ◽  
Frozen Storage ◽  
Freezing Process ◽  
Liquid Media ◽  
Nitrite Concentration ◽  
Microbial Cultures ◽  
Nitrate Losses

Abstract The effects of freezing on nitrite stability in microbial cultures and in other liquid media were examined. Nitrite (12-13 mg (NO2)N/ 100 mL, pH 5.7) in culture and aqueous media was very unstable during frozen storage. Freezing resulted in the degradation of nitrite to other products including nitrate. Losses of 38-57% of the nitrite occurred after 15 days of frozen storage. Neither addition of chloroform nor a 5 min boiling treatment before freezing prevented nitrite destruction. However, nitrite concentration in the unfrozen portion of aqueous media increased during the freezing process. Nitrite can be stabilized during frozen storage by increasing the pH to near 11.0. For aqueous solutions, nitrite can be preserved by the use of chloroform or by increasing the pH to 11.0 and storing at 5°C.

scholarly journals pH and Redox Induced Color Changes in Protein Crystals Suffused with Dyes

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 126 ◽  
Author(s):  
Alexander McPherson
Keyword(s):  
Ascorbic Acid ◽  
Redox Potential ◽  
Mother Liquor ◽  
Ph Sensitive ◽  
Protein Crystals ◽  
Ph Changes ◽  
Color Changes ◽  
Chemical Factors ◽  
Diffusion Rates ◽  
Over Time

Protein crystals, otherwise usually colorless, can be stained a variety of hues by saturating them with dyes, by diffusion from the mother liquor or co-crystallization. The colors assumed by dyes are a function of chemical factors, particularly pH and redox potential. Protein crystals saturated with a pH sensitive dye, initially at one pH, can be exposed to the mother liquor at a second pH and the crystal will change color over time as H3O+ ions diffuse through the crystal. This allows diffusion rates of H3O+ through the crystal to be measured. Diffusion fronts are often clearly delineated. Similar experiments can be carried out with redox sensitive dyes by adding reductants, such as ascorbic acid or dithionite, or oxidants such as H2O2, to the crystal’s mother liquor. Presented here are a number of experiments using pH or redox sensitive dye-saturated protein crystals, and some experiments using double dye, sequential redox–pH changes.

Sign in / Sign up

Export Citation Format

Share Document