- Thermodynamics of the hydrolysis of TRISH+ in (water + 10 or + 20 mass per cent of acetonitrile) from 263.15 to 298.15 K
-
The standard potentials of (AgCl + 1/2H2 = Ag + HCl) in (water + 10 or + 20 mass per cent of acetonitrile) were used to determine the acidity constants of protonated tris(hydroxymethyl)aminomethane (TRISH+).Measurements were made at eight temperatures ranging from 263.15 to 298.15 K at 5 K intervals in cells without liquid junction.The molalities of TRISH+ ranged from 0.1 to 0.005 mol * kg-1.The standard molar Gibbs free energy change ΔrGm0 of the reaction was calculated.From the values obtained in the literature for water and our values for the mixed solvents, the standard molar Gibbs free energy of transfer ΔtGm0 was also estimated.It was found that the hydrolysis of TRISH+ is less favored in the mixtures than in pure water.
- Vega, Carmen A.,Vila, Pablo
-
-
Read Online
- Sanger dideoxy sequencing of DNA
-
While the ease and reduced cost of automated DNA sequencing has largely obviated the need for manual dideoxy sequencing for routine purposes, specific applications require manual DNA sequencing. For instance, in studies of enzymes or proteins that bind or modify DNA, a DNA ladder is often used to map the site at which an enzyme is bound or a modification occurs. In these cases, the Sanger method for dideoxy sequencing provides a rapid and facile method for producing a labeled DNA ladder.
- Walker, Sarah E.,Lorsch, Jon
-
-
Read Online
- Solution Dynamics of Hybrid Anderson-Evans Polyoxometalates
-
Understanding the stability and speciation of metal-oxo clusters in solution is essential for many of their applications in different areas. In particular, hybrid organic-inorganic polyoxometalates (HPOMs) have been attracting increasing attention as they combine the complementary properties of organic ligands and metal-oxygen nanoclusters. Nevertheless, the speciation and solution behavior of HPOMs have been scarcely investigated. Hence, in this work, a series of HPOMs based on the archetypical Anderson-Evans structure, δ-[MnMo6O18{(OCH2)3C-R}2]3-, with different functional groups (R = -NH2, -CH3, -NHCOCH2Cl, -NCH(2-C5H4N) {pyridine; -Pyr}, and -NHCOC9H15N2OS {biotin; -Biot}) and countercations (tetrabutylammonium {TBA}, Li, Na, and K) were synthesized, and their solution behavior was studied in detail. In aqueous solutions, decomposition of HPOMs into the free organic ligand, [MoO4]2-, and free Mn3+ was observed over time and was shown to be highly dependent on the pH, temperature, and nature of the ligand functional group but largely independent of ionic strength or the nature of the countercation. Furthermore, hydrolysis of the amide and imine bonds often present in postfunctionalized HPOMs was also observed. Hence, HPOMs were shown to exhibit highly dynamic behavior in solution, which needs to be carefully considered when designing HPOMs, particularly for biological applications.
- Salazar Marcano, David E.,Lentink, Sarah,Moussawi, Mhamad A.,Parac-Vogt, Tatjana N.
-
supporting information
p. 10215 - 10226
(2021/05/31)
-
- COMPOSITION FOR STERILIZATION AND CLEANING, METHOD FOR PRODUCING SAME, AND STERILIZATION AND CLEANING METHOD EMPLOYING SAME
-
A composition for sterilization and cleaning which comprises 0.001-30 mass % peracetic acid, 0.001-30 mass % hydrogen peroxide, 1-70 mass % acetic acid and/or salt thereof, 0.001-5 mass % polyoxyethylene lauryl ether acetate or salt thereof, and water, the composition having a pH of 4.0-10.0.
- -
-
-
- PROTEIN STERILISATION BY RADIATION AND ADDITION OF A STABILISING COMPOSITION
-
A method of sterilising a protein, comprises exposing to ionising radiation an at least substantially dry composition comprises a protein and a protective compound or combination of protective compounds having both of the following characteristics: (i) a rate of reaction with singlet oxygen greater than 1×10 7 L mol?1 S?1; (ii) being a reducing agent whilst at the same time containing a proton dissociable group with a pKa no more than 3 units from the pH of the composition. The compound having characteristic (i) is selected from histidine, thiamine and tryptophan, the compound having characteristic (ii) is selected from methionine, malate, citrate, lactate and tiron. The radiation is gamma radiation or electron beam, whereby the preferred dose is 15-40 kGy.
- -
-
-
- Topical acne vulgaris composition with a sunscreen
-
Increased compliance in the use of topical sunscreens is obtained by combining a topical sunscreen agent in a formulation containing an antibacterial medication such as azelaic acid or an antibiotic.
- -
-
-
- The multiple Maillard reactions of ribose and deoxyribose sugars and sugar phosphates
-
Ribose 5-phosphate (R5P) undergoes the Maillard reaction with amines at significantly higher rates than most other sugars and sugar phosphates. The presence of an intramolecular phosphate group, which catalyzes the early stages of the Maillard reaction, provides the opportunity for the R5P molecule to undergo novel reaction paths creating unique Maillard products. The initial set of reactions leading to an Amadori product (phosphorylated) and to an α-dicarbonyl phosphate compound follows a typical Maillard reaction sequence, but an observed phosphate hydrolysis accompanying the reaction adds to the complexity of the products formed. The reaction rate for the loss of R5P is partially dependent on the pKa of the amine but also is correlated to the protonation of an early intermediate of the reaction sequence. In the presence of oxygen, a carboxymethyl group conjugated to the amine is a major product of the reaction of R5P with N-acetyllysine while little of this product is generated in the absence of oxygen. Despite lacking a critical hydroxyl group necessary for the Maillard reaction, 2-deoxyribose 5-phosphate (dR5P) still generates an Amadori-like product (with a carbonyl on the C-3 carbon) and undergoes phosphate cleavage. Two highly UV-absorbing products of dR5P were amine derivatives of 5-methylene-2-pyrrolone and 2-formylpyrrole. The reaction of dR5P with certain amines generates a set of products that exhibit an interesting absorbance at 340 nm and a high fluorescence.
- Munanairi, Admire,O'Banion, Steven K.,Gamble, Ryan,Breuer, Elizabeth,Harris, Andrew W.,Sandwick, Roger K.
-
p. 2575 - 2592
(2008/03/27)
-
- Topical acne vulgairs medication with a sunscreen
-
Increased compliance in the use of topical sunscreens is obtained by combining a topical sunscreen agent in a formulation containing an antibacterial medication such as azelaic acid or an antibiotic.
- -
-
-
- Structure-stability correlations for imine formation in aqueous solution
-
Imine formation between 25 aldehydes and 13 amines in aqueous solution in the pH range 7-11 was studied by 1H NMR spectroscopy. A three-parameter linear equation correlating logarithms of imine formation constants with pKa and HOMO energies of amines and LUMO energies of aldehydes is proposed. In view of the widespread occurrence of imine-forming processes in both chemistry and biology, the data presented are of significance for physical organic chemistry and of particular interest for dynamic combinatorial chemistry. Copyright
- Godoy-Alcantar,Yatsimirsky, Anatoly K.,Lehn
-
p. 979 - 985
(2007/10/03)
-
- Phase equilibria in the system silicofluoric acid-tris-(oxymethyl) aminomethane-water at 25°C
-
The interaction in the silicofluoric acid-tris(oxymethyl)aminomethane (TRIS)-H2O system has been studied at 25°C by the isothermal solubility method. A new compound 2TRIS·H2SiF6 has been found and characterized by elemental analysis, IR and mass spectroscopy, and thermogravimetry. The compound solubility along the crystallization curve varies within 22.28-47.94 wt %.
- Gel'mbol'dt,Gavrilova,Sokhranenko,Ennan
-
p. 1431 - 1433
(2008/10/08)
-
- Ophthalmic aqueous pharmaceutical preparation
-
The present invention provides an ophthalmic aqueous pharmaceutical preparation, which is excellent in anti-inflammatory effect, which is less stimulative and which has high safety and excellent storage stability. The ophthalmic aqueous pharmaceutical preparation comprises meloxicam and trometamol.
- -
-
-
- Compositions of matter having bioactive properties
-
Particles of coordinated complex comprising a basic, hydrous polymer and a capacitance adding compound, as well as methods for their production, are described. These complexes exhibit a high degree of bioactivity making them suitable for a broad range of applications through their incorporation into conventional vehicles benefiting from antimicrobial and similar properties.
- -
-
-
- Composition of matter having bioactive properties
-
Particles of coordinated complex comprising a basic, hydrous polymer and a capacitance adding compound, as well as methods for their production, are described. These complexes exhibit a high degree of bioactivity making them suitable for a broad range of applications through their incorporation into conventional vehicles benefiting from antimicrobial and similar properties.
- -
-
-
- Hydroxy-group containing acylated nitrogen compositions useful as additives for lubricating oil and fuel compositions
-
Compositions comprising hydroxyl group containing acylated nitrogen compounds, a process for reacting certain carboxylic reactants with olefinic compounds then reacting the product prepared thereby with ammonia, a hydrazine or an amine, products prepared thereby and lubricating oil and fuel compositions.
- -
-
-
- Antifungal cyclohexapeptides
-
The present invention is directed to novel carba cyclohexapeptide compounds of the formula STR1 where all substituents are defined herein, which are useful as antifungal agents and for the treatment of Pneumocystis carinii infections. Compositions containing the compounds of the invention are also disclosed.
- -
-
-
- Linear oligomeric polychelant compounds
-
Linear oligomer polychelant compounds and chelates formed therewith have alternating chelant and linker moieties bound together by amide or ester moieties. The compounds have between 3 and 100 chelant moieties, at least one of which complexes a paramagnetic metal ion. The polychelants and especially their paramagnetic metal polychelates are particularly suitable for diagnostic imaging.
- -
-
-
- Injectable mesna solutions
-
Injectable mesna solutions having a pH value higher than 7.5. The solutions have increased storage stability.
- -
-
-
- Synthesis and Hydrolytic Lability of α-Phenoxyacetamides Containing Hydroxy Groups in the N-alkyl Residue
-
Secondary and tertiary amides of 3,5-biscarbonyl>phenoxyacetic acid bearing hydroxy groups in positions β (β-OH) and γ (γ-OH) relative to the acetamide nitrogen atom have been synthesized.Such amides easily undergo cleavage of the acetamide bond in water at neutral pH.Hydrolysis rate constant for a series of such amides and protonation constants for the corresponding leaving amines were determined.No simple correlation between the two parameters could be found.A study of the dependence of these parameters on the structural features of the substrates, such as the presence of an N-methyl group and number of β-OH and γ-OH groups, was carried out.All these features lead to enhancement of the amide hydrolysis rate and a synergistic effect is operative when both N-methyl and β-OH groups are contained in the substrate.Presence of a methyl group increases the basicity of amines whereas β-OH and γ-OH groups have the opposite effect.Mechanistic speculations seem to indicate that the abnormal lability of the acetamide bond is due to protic-like catalysis by an intramolecular OH...N hydrogen bond.
- Anelli, Pier Lucio,Brocchetta, Marino,Canipari, Sonia,Losi, Pietro,Manfredi, Giuseppe,et al.
-
p. 135 - 142
(2007/10/03)
-
- A systematic entropy relationship for the general-base catalysis of the deprotonation of a carbon acid. A quantitative probe of transition-state solvation
-
The general-base-catalyzed deprotonation of a carbon acid, the l-methyl-4-(phenylacetyl)pyridinium cation (pKa = 9.02 at 25 °C), has been investigated for 32 general-base catalysts (25 amines and seven phenoxide ions) in aqueous solution. Amines give a generally scattered Bronsted plot; ring-substituted benzylamines have ?= 0.52, and ring-substituted phenoxides have ?= 0.60, with the phenoxides being more reactive than amines of similar basicity. The temperature dependences of the general-base-catalyzed deprotonation of this carbon acid have been measured over the range 15-45 °C for 12 base catalysts (eight primary, secondary, and tertiary amines; 4-(dimethylamino)pyridine; two phenoxide ions; hydroxide ion). The entropies of activation for these deprotonations show a clean curvilinear dependence upon the entropies of protonation of these base species, with the hydroxide ion being the only significant deviant from this relationship. This observation quantitatively establishes the importance of solvation effects as the major source of deviations that are commonly observed in Bronsted relationships for general-base-catalyzed processes.
- Bunting, John W.,Stefanidis, Dimitrios
-
p. 779 - 786
(2007/10/02)
-
- Renin inhibiting peptides with polar end groups
-
The present invention provides novel renin-inhibiting peptides having a noncleavable transition state insert corresponding to the 10,11- position of the renin substrate (angiotensinogen) and a polyhydroxy-substituted alkyl moiety bonded directly through carbon or nitrogen to the N-terminus. Such inhibitors are useful for the diagnosis and control of renin-dependent hypertension and other related diseases.
- -
-
-
- Maleimido substituted aromatic cyclotriphosphazenes
-
4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g. hexakis amino or trisaminophenoxy-trisphenoxy-cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.
- -
-
-
- Solubilized platinum (II) complexes
-
There are described platinum-polyhydroxylated amine compounds which exhibit anti-tumor activity in mammalian species. The products are highly soluble in aqueous solutions and they may be administered either orally or in parenteral form.
- -
-
-
- 9-Thiaprostaglandins
-
7-[3α-(3-hydroxy-3-hydrocarbylpropyl, or -1-propenyl, or 1-propynyl)-4-hydroxy-tetrahydro-2β-thienyl]-heptanoic or 5-heptenoic acids, sulfoxides, sulfones, esters or salts thereof are stable, prostaglandin-like acting and antiasthmatic agents.
- -
-
-
- 9-Thiaprostaglandins
-
7-[3α-(3-hydroxy-3-hydrocarbylpropyl, or -1-propenyl, or 1-propynyl)-4-hydroxy-tetrahydro-2β-thienyl]-heptanoic or 5-heptenoic acids, sulfoxides, sulfones, esters or salts thereof are stable, prostaglandin-like acting and antiasthmatic agents.
- -
-
-
- 9-Thiaprostaglandins
-
7-[3α-(3-hydroxy-3-hydrocarbylpropyl,-1-propenyl or -propynyl)-4-hydroxy-tetrahydro-2β-thienyl -heptanoic or 5-heptenoic acids, sulfoxides, sulfones, esters or salts thereof are stable, prostaglandin-like acting and antiasthmatic agents.
- -
-
-
