Experimental Results to Design Lactic Acid for Carbonate Acidizing

Acidizing deep carbonate formations by Hydrochloric acid (HCl) is a complex task due to high reaction and corrosion rates. Mixing organic acids with HCl is a typical method to reduce the acid's reactivity and corrosivity. Lactic acid has not been investigated completely in the area of carbonate acidizing. Lactic acid has a dissociation constant similar to formic acid, which is approximately 10 times larger than acetic acid. Therefore, the objective of this work is to compare lactic/HCl blends with plain HCl and formic/HCl blends. Corrosion tests were conducted at high temperature on C-95 steel coupons to investigate associated corrosion damage. Coreflood tests were performed on Indiana limestone cores to mimic matrix acidizing treatment and to investigate amount of pore volumes required to breakthrough. All blends were prepared to be equivalent to 15 wt% (4.4 M) HCl for comparison. Lactic and formic acid concentrations were set to be (0.5 or 1 M), and HCl concentration was calculated as appropriate to reach a blend with strength of 4.4 M. In terms of corrosivity evaluation, blends of lactic and HCl acids showed a corrosion rate of up to 1.97 lb/ft2 at 300°F. The formic and HCl blend showed a corrosion rate of 1.68 lb/ft2 at the same temperature. The difference in corrosion rates between the two mixtures is due to molecular weight difference between lactic and formic acids. When both acids were prepared at 1 M, lactic acid blend required more HCl to be equivalent to 15 wt% HCl acid which was associated with an increase in corrosion rate. Coreflood results established acid efficiency curves for lactic/HCl acid blends. The curves highlighted the correlation between acid-core reactivity, injection rate, and dissolution pattern. Lactic/HCl blend was less reactive than formic/HCl mixture as the last required lower injection rate to obtain optimum pore volume to breakthrough at 300°F. Lactic/HCl blend was able to generate an optimum dissolution pattern as a dominant wormhole was shown on tested core plugs inlet face. This study expands the investigation of lactic acid utilization in carbonate acidizing. Major advantages rendered by using lactic acid with HCl include: (1) favorable dissolution pattern due to lactic acid being less reactive than HCl or formic acids, and (2) less corrosion rates comparing to HCl, that can reduce allocated costs for maintenance and replacements.

Changesin Myoglobin of Big Eye Tuna During Chilling Storage

Big eye tuna (Thunnus obesus) is one of the species of tuna which is have some value added such as have potential to improve animal protein sources, have high economic values as well as an export commodity.Mishandling and misapplication of high temparatures on the tuna handling at the tropics and sub tropics climate was significantly decreasing the value of myoglobin and affecting the solubility of protein. Myoglobin is a globular protein that have small molecular weight size and it was an important factor for determining the quality of meat and influencing factors of purchasing power by the consumer. The purpose of this experiments is to determining the changes of myoglobin content and the water soluble proteins content at some parts of big eye tuna in 9 days chilling temperatures. The portion which is analized was the ventral area, dorsal area and tail area. Myoglobin content in all portion above, both light and dark meat was analized. The results shows the decreased value of myoglobin content from first handling (day zero) until day ninth (days 9th) experiment. Each myoglobin contentfrom white meat at at ventral, dorsal and tail meat was decreased from 121.68 mg/100 into 41.35 mg/100, 148.2 mg/100g into 52.01 mg/100g, 105.16 mg/100g into 31.34 gr/100gram, after day ninth. The myoglobin content from dark meat at ventral, dorsal and tail meat, was decreased, too ; from 418.64 mg/100 gr into 121.01 mg/100 g, 446.21 mg/100 g into 58.34 mg/100 r and 145.65 mg/100 gr into 87.98 mg/100g after day ninth.Water soluble protein was derived into protein bands with molecular weight 15,4 kDa and 14 kDa. Its suspected as the myoglobin protein. The molecular weight difference was caused from degradation of protein during the storage.<br />Keywords: Big eye tuna, meat, storage, myoglobin

Genetic polymorphism of platelet glycoprotein Ib

Platelet glycoprotein (GP) Ib from 131 healthy Japanese was analyzed using SDS-polyacrylamide gel electrophoresis and specific staining with peroxidase-coupled wheat germ agglutinin after it was transferred to nitrocellulose membranes. Four slightly different species of GPIb were observed and designated as A, B, C, and D for glycoproteins with molecular weights of 168,000, 162,000, 159,000, and 153,000 daltons, respectively. The respective gene frequencies were calculated to be .073, .011, .561, and .355 for A-, B-, C-, D-type GPIb. Portions from each type of GPIb molecule (alpha-chain and glycocalicin) showed heterogeneity with the same molecular weight difference, indicating that the variance would be derived from the polypeptide portion that is exposed to the outer medium. The different types of GPIb were the same with respect to their accessibility to lactoperoxidase, reactivity to lectins, and affinity to TLCK-thrombin. Although Bolin et al reported patients with a bleeding tendency whose platelets have double GPIb bands, here we found that platelets with different GPIb phenotypes showed no significant differences in aggregating activity and platelet retention. Analysis of GPIb phenotype should be important for structural and physiologic studies on GPIb and glycocalicin.

Genetic polymorphism of platelet glycoprotein Ib

Platelet glycoprotein (GP) Ib from 131 healthy Japanese was analyzed using SDS-polyacrylamide gel electrophoresis and specific staining with peroxidase-coupled wheat germ agglutinin after it was transferred to nitrocellulose membranes. Four slightly different species of GPIb were observed and designated as A, B, C, and D for glycoproteins with molecular weights of 168,000, 162,000, 159,000, and 153,000 daltons, respectively. The respective gene frequencies were calculated to be .073, .011, .561, and .355 for A-, B-, C-, D-type GPIb. Portions from each type of GPIb molecule (alpha-chain and glycocalicin) showed heterogeneity with the same molecular weight difference, indicating that the variance would be derived from the polypeptide portion that is exposed to the outer medium. The different types of GPIb were the same with respect to their accessibility to lactoperoxidase, reactivity to lectins, and affinity to TLCK-thrombin. Although Bolin et al reported patients with a bleeding tendency whose platelets have double GPIb bands, here we found that platelets with different GPIb phenotypes showed no significant differences in aggregating activity and platelet retention. Analysis of GPIb phenotype should be important for structural and physiologic studies on GPIb and glycocalicin.

Biogenesis of membrane-bound and secreted immunoglobulins. I. Two distinct translation products of human mu-chain, with identical N-termini and different C-termini.

Structural differences between the heavy chain of membrane-bound IgM (mu m) and the heavy chain of secreted IgM (mu s) were investigated. The primary translation products of the mu-chain, free of posttranslational modifications, were synthesized in a wheat-germ cell-free system, programmed with messenger RNA derived from human lymphoblastoid cell lines positive for both membrane-bound and secreted IgM. Encoded in this sytem were two mu-chains, which shared N-terminal signal peptides and which differed both in molecular weight and in C-terminal amino acid sequence. In vivo pulse labeling of cells confirmed that, as intermediates in the rough endoplasmic reticulum, these two forms expressed the same idiotype and maintained their difference in molecular weight and in C-terminal sequence. By correlation with pulse-chase kinetics and with immunofluorescence, one form of mu-chain represents mu m, and the other, mu s. Because the molecular weight difference between the two is manifest at the level of their primary translation products, these studies demonstrate that mu m is distinguished from mu s by a difference in primary structure, at least in part at the C-terminus.

The Molecular Weights of Rubber and Related Materials: I. Experimental Methods

The osmotic molecular weight of crepe has been measured in several solvents. It is shown that the use of a poor solvent, or a mixture of solvent and precipitant, gives solutions which approach ideal osmotic behavior. Benzene containing 150 cc. of methanol per liter is the best solvent examined, 1 per cent solutions of crepe being almost ideal. Viscosity data are employed to calculate absolute weight average molecular weights, the Staudinger constant being determined by comparison with ultracentrifuge data. Constants are listed for a number of solvents, and shown to vary only by a small factor. The osmotic and viscosity molecular weights of a number of rubbers are compared; the two values agree for three rubber fractions, while for unfractionated materials the viscosity average is the higher. Non-uniformity coefficients are calculated from the ratio of the two molecular weights. The molecular weight of sol rubber is higher than that of gel, showing that the sol-gel separation does not arise from molecular weight difference. The Staudinger law is shown to hold for rubber solutions at least over the molecular weight range 350,000–60,000, and probably very much further.