Modification of the NRTL and Wilson models for the representation of phase equilibrium behavior of aqueous amino acid – electrolyte solutions

2008 ◽  
Vol 86 (12) ◽  
pp. 1126-1137 ◽  
Author(s):  
Rahmat Sadeghi
Keyword(s):  
Amino Acids ◽  
Phase Equilibrium ◽  
Amino Acid ◽  
Electrolyte Solutions ◽  
Acid Electrolyte ◽  
Amino Acid Molecule ◽  
Local Composition ◽  
Equilibrium Behavior ◽  
Amino Acid Solutions ◽  
Solid Liquid

The extended NRTL and Wilson local composition models for amino acid solutions have been modified for the representation of the phase equilibrium behavior of aqueous amino acid – electrolyte solutions by considering cells with random composition for the reference Gibbs energies or enthalpies of local composition cells with a central amino acid molecule and also with a central ion. These new local composition models, which have a molecular thermodynamic framework, have been used to model the vapor–liquid and solid–liquid equilibrium behavior of amino acids and small peptides in aqueous solutions as functions of temperature, ionic strength, and amino acid compositions. The utility of the models is demonstrated with a successful representation of the activity coefficients and the solubility of several amino acids in different aqueous solutions.Key words: amino acid, NRTL, Wilson, activity coefficient, solubility, aqueous solution.

scholarly journals An aquatic vertebrate can use amino acids from environmental water

2016 ◽  
Vol 283 (1839) ◽  
pp. 20160996 ◽  
Author(s):  
Noboru Katayama ◽  
Kobayashi Makoto ◽  
Osamu Kishida
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Dissolved Organic Matter ◽  
Larval Growth ◽  
Environmental Water ◽  
Acid Solutions ◽  
Aquatic Vertebrates ◽  
Amino Acid Solutions ◽  
Salamander Larvae

Conventional food-web theory assumes that nutrients from dissolved organic matter are transferred to aquatic vertebrates via long nutrient pathways involving multiple eukaryotic species as intermediary nutrient transporters. Here, using larvae of the salamander Hynobius retardatus as a model system, we provide experimental evidence of a shortcut nutrient pathway by showing that H. retardatus larvae can use dissolved amino acids for their growth without eukaryotic mediation. First, to explore which amino acids can promote larval growth, we kept individual salamander larvae in one of eight different high-concentration amino acid solutions, or in control water from which all other eukaryotic organisms had been removed. We thus identified five amino acids (lysine, threonine, serine, phenylalanine, and tyrosine) as having the potential to promote larval growth. Next, using 15 N-labelled amino acid solutions, we demonstrated that nitrogen from dissolved amino acids was found in larval tissues. These results suggest that salamander larvae can take up dissolved amino acids from environmental water to use as an energy source or a growth-promoting factor. Thus, aquatic vertebrates as well as aquatic invertebrates may be able to use dissolved organic matter as a nutrient source.

Opiate nerves mediate feline pyloric response to intraduodenal amino acids

1985 ◽  
Vol 248 (3) ◽  
pp. G307-G312 ◽  
Author(s):  
J. C. Reynolds ◽  
A. Ouyang ◽  
S. Cohen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Spike Activity ◽  
Saline Control ◽  
Myoelectric Activity ◽  
Neural Pathways ◽  
Acid Solutions ◽  
Cervical Vagotomy ◽  
Amino Acid Solutions ◽  
Dose Dependent

Intraluminal pressures and myoelectric activity were recorded from the feline antrum, pylorus, and duodenum in response to intraduodenal amino acid solutions. Mixed amino acids (0.02 mg/ml, 3.0 ml) increased the amplitude of pyloric contractions (59.7 +/- 7.9 mmHg) and pyloric spike activity (73.7 +/- 6.8% of slow waves with spike activity) compared with a saline control (P less than 0.001). The selectivity of these responses was determined with specific amino acids. L-Tryptophan (10 or 40 mM) produced a response similar to the mixed amino acid response, while L-phenylalanine or L-glycine (10 or 40 mM) had no effect. Intra-arterial tetrodotoxin, intraluminal ethyl aminobenzoate, or intravenous naloxone (1.0 mg/kg) abolished the pyloric responses to amino acids (P less than 0.02). Bilateral cervical vagotomy had no effect. Cholecystokinin octapeptide (CCK-OP) produced dose-dependent increases in the amplitude of pyloric contractions and in pyloric spike activity. The ED50 dose of CCK-OP (1.0 microgram/kg iv) gave an increase in pyloric pressure of 155.6 +/- 49.9 mmHg and in spike activity of 77.7 +/- 9.4%, similar to mixed amino acids or tryptophan. These effects of CCK-OP were not antagonized, however, by a dose of naloxone (1.0 mg/kg) that blocked the maximal pyloric response to leucine-enkephalin. We concluded intraduodenal mixed amino acids or tryptophan increase phasic, spike-dependent pyloric contractions in the cat via nonvagal, naloxone-sensitive neural pathways, phenylalanine, a structurally similar essential amino acid, had no effect on the feline gastroduodenal junction, and the pyloric responses to exogenous CCK-OP are mediated by pathways distinct from the responses to tryptophan or mixed amino acids.

Consumption of Amino Acid Solutions by Anastrepha suspensa Loew (Diptera: Tephritidae)

2007 ◽  
Vol 42 (3) ◽  
pp. 368-374
Author(s):  
Herbert N. Nigg ◽  
Rhonda A. Schumann ◽  
Jing J. Yang ◽  
Suzanne Fraser
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fruit Fly ◽  
Acid Solutions ◽  
Anastrepha Suspensa ◽  
Caribbean Fruit Fly ◽  
Choice Tests ◽  
Amino Acid Solutions ◽  
Males And Females

The consumption of amino acids by Anastrepha suspensa Loew (Caribbean fruit fly) was quantified by measuring individual fly consumption. For no-choice tests, there were no differences in consumption between 0.2 M sucrose and 0.2 M sucrose plus L-alanine, L-glycine, L-histidine, L-phenylalanine, or L-serine solutions. There was increased consumption of 0.05 M L-lysine by 6-d males and of 0.03 M L-valine solutions by 6-d females compared to sucrose alone. Choice tests showed higher consumption of 0.2 M sucrose plus L-lysine, L-valine, and L-glycine, particularly by 6-d-old flies. There was a 3–8X increase in consumption of 0.05 M L-valine in 0.2 M sucrose for 6-d males and females. Commercial L-lysine, L-methionine, and L-taurine were not different from controls in no-choice tests; L-cysteine was about 95% inhibitory for consumption. Based on these data, better consumed A. suspensa baits might be formulated by eliminating L-cysteine and including 0.05 M L-valine.

Solubility of xenon in amino‐acid solutions. II. Nine less‐soluble amino acids

1988 ◽  
Vol 88 (10) ◽  
pp. 6529-6533 ◽  
Author(s):  
Richard P. Kennan ◽  
Jeffrey F. Himm ◽  
Gerald L. Pollack
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Solutions ◽  
Amino Acid Solutions

Stability of Famotidine in Minibags Refrigerated and/or Frozen in Total Parenteral Nutrition Solutions

DICP ◽  
1989 ◽  
Vol 23 (10_suppl) ◽  
pp. S44-S46
Author(s):  
Linda S. Bullock
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Parenteral Nutrition ◽  
Gastrointestinal Bleeding ◽  
Total Parenteral Nutrition ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Room Temperature ◽  
Acid Solutions ◽  
Amino Acid Solutions

The use of histamine2-receptor antagonists could be beneficial in critically ill patients for protection against stress-induced gastrointestinal bleeding. Famotidine, similar to cimetidine and ranitidine, is stable when mixed in dextrose 5% injection and NaCl 0.9% injection at a concentration of 200 μg/mL and stored in polyvinyl chloride bags at 4 °C for 14 days or when frozen for 28 days and subsequently refrigerated for 14 days. Furthermore, famotidine, also like cimetidine and ranitidine, is stable when added to most common total parenteral nutrition (TPN) solutions. Famotidine in concentrations of 20 mg/L and 40 mg/L is stable in crystalline amino acid solutions (20 g/L and 42.5 g/L) when refrigerated for 24 hours, then held at room temperature for 24 hours, at room temperature for 48 hours, or refrigerated for seven days. The concentration of amino acids in the TPN solutions containing 42.5 g/L also is not affected by the addition of famotidine 40 mg/L when stored under conditions similar to those stated above for 48 hours. TPN solutions remain clear and free of turbidity.

scholarly journals Interactive Auditory Navigation in the Molecular Structures of Amino Acids: A Case Study Using Multiple Concurrent Sound Sources Representing Nearby Atoms

2019 ◽  
Author(s):  
Danyi Liu ◽  
Edwin van der Heide
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Research And Development ◽  
Three Dimensional ◽  
Molecular Structures ◽  
Acid Molecule ◽  
Auditory Masking ◽  
Amino Acid Molecule ◽  
Sound Sources

We are interested in sonifying the molecular structures of amino acids. This paper describes the context and the first design choices for our approach. So far, we believe an amino acid molecule is too complex to be perceived at once. Therefore, we have designed an interactive form of sonification in which the listener navigates through the molecule over the network of carbon atoms. We describe our different approaches and discuss the topic of immediacy: the time it takes to recognize the structure surrounding the listener’s position while navigating. Furthermore, we touch upon the question how many atoms we can sonify simultaneously and the role auditory masking plays in this context. To overcome auditory masking, we propose to use irregular but easy to recognize sounds. We conclude with an interest in a three-dimensional navigation environment using general molecular structures for further research and development.

Plasma Amino Acids in Patients with Acute Nonlymphocytic Leukemia Receiving Parenteral Nutrition

1993 ◽  
Vol 27 (2) ◽  
pp. 146-150
Author(s):  
Michael L. Christensen ◽  
Julienne Burgess ◽  
Richard A. Helms ◽  
Joseph Mirro ◽  
David K. Kalwinsky ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Parenteral Nutrition ◽  
Acid Solution ◽  
Plasma Amino Acid ◽  
Acid Solutions ◽  
Acute Nonlymphocytic Leukemia ◽  
Amino Acid Solution ◽  
Amino Acid Solutions ◽  
Amino Acid Concentrations

Objective To assess the effect of parenteral amino acid solutions on plasma amino acid concentrations in patients with acute nonlymphocytic leukemia (ANLL) receiving parenteral nutrition (PN). Design Ten patients were studied at diagnosis, on the morning PN was started, and three times during PN therapy coinciding with the sequential administration of three different amino acid solutions (Aminosyn, FreAmine HBC, and TrophAmine). The order of amino acid solution administration in each patient was by a randomized, block design. Results The patients were undergoing identical intensive induction therapy. There was no significant difference in the number of days they received PN or the amount of protein or calories received during the three PN study periods. At diagnosis, phenylalanine and glutamic acid concentrations were elevated compared with previously published normal values and remained elevated at all observation times. During PN, asparagine, aspartic acid, and tyrosine concentrations were significantly lower with all three amino acid solutions compared with their concentrations at diagnosis. Glycine and threonine concentrations were also significantly lower with FreAmine HBC and TrophAmine administration and cysteine concentrations were significantly lower with FreAmine HBC administration than at the time of diagnosis. Aminosyn was associated with plasma amino acid concentrations most similar to those measured at diagnosis. Conclusions These results indicate that most amino acid concentrations fall within the normal range at diagnosis in the ANLL patients studied. Plasma concentrations for certain amino acids can be influenced by the amino acid solution used in PN. Further understanding of the derangements in amino acid metabolism and the influence of parenterally administered amino acid solutions on plasma amino acid concentrations may lead to improvements in the nutritional support of cancer patients.

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