sodium-acetate--anhydrous and potassium-phosphate

This study investigated the performance and feasibility for application of different buffer agent combinations, including K2HPO4/MgSO4, KH2PO4/MgSO4 and NaAc, in composting of food waste. The variations of temperature, pH, O2 consumption, organic mass and ammonia release were monitored. The results showed that addition of all these three types of agents could prolong the thermophilic stage during composting. The amendments of KH2PO4/MgSO4 and NaAc could increase and decrease the final pH levels, respectively. Application of K2HPO4/MgSO4 and NaAc would lead to a peak daily oxygen uptake rate of 10.0 and 12.4 mg/(g·h) respectively, which were all higher than that with KH2PO4/MgSO4 amendment. Similarly, the reactors with K2HPO4/MgSO4 and NaAc were also associated with a higher cumulative oxygen uptake and total organic degradation rate. The amendment of NaAc resulted in a higher ammonia loss than the other two agents. More inorganic nitrogen contents were observed in the series with K2HPO4/MgSO4 and NaAc. It can be concluded that K2HPO4/MgSO4 additive showed the most favorable influence on composting performance. The results of this study will have important implications for developing appropriate treatment approach for food waste composting.

Topics: Ammonia; Analysis of Variance; Buffers; Food; Hydrogen-Ion Concentration; Oxygen Consumption; Phosphates; Potassium Compounds; Sodium Acetate; Soil; Soil Microbiology; Temperature; Waste Products

The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel.. In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis.. The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations.. The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration.. A consistently higher level of fluoride in saliva should be a goal in caries prevention.

Topics: Acetic Acid; Amines; Calcium; Calcium Chloride; Cariostatic Agents; Cellulose; Dental Enamel; Electron Probe Microanalysis; Fluorides; Humans; Hydrogen-Ion Concentration; Materials Testing; Microscopy, Electron, Scanning; Microscopy, Polarization; Phosphates; Phosphorus; Potassium Chloride; Potassium Compounds; Saliva, Artificial; Sodium Acetate; Spectrometry, X-Ray Emission; Temperature; Tooth Demineralization; Tooth Remineralization

Statistics-based experimental designs were used to develop a cost-effective medium for enhanced production of viable cells and bacteriocin by probiotic Enterococcus faecium MC13. Carbon, nitrogen, and mineral sources were first screened by one-variable-at-a-time (OVAT) methods. In order to increase yield production, the selected variables were further statistically optimized using response-surface methodology (RSM) with central composite design (CCD). The maximum and minimum levels of the selected variables were determined and a set of 34 experimental runs was performed. The optimum concentrations of the tested variables for production of viable cells (12.24 log CFU mL(-1)) and bacteriocin activity (25,600 AU mL(-1)) were tryptone (10.0 g/L), peptone (6.0 g/L), maltose (3.0 g/L), glucose (9.0 g/L), NaCl (15.0 g/L), sodium citrate (2.5 g/L), sodium acetate (1.0 g/L), and dipotassium PO(4) (0.1 g/L). Threefold increased yield of bacteriocin was achieved in optimized medium compared to the unoptimized counterpart, and this was two times less cost than commercial MRS medium.

Topics: Bacteriocins; Citrates; Culture Media; Enterococcus faecium; Food Microbiology; Glucose; Industrial Microbiology; Maltose; Models, Statistical; Peptones; Phosphates; Potassium Compounds; Probiotics; Sodium Acetate; Sodium Chloride; Sodium Citrate

The polymers containing ribose rings: poly(5'-acrylamido-5'-deoxy-1',2'-O-isopropylidene-alpha-D-ribose) (11), poly(5'-acrylamido-5'-deoxy-alpha-D-ribose) (12) and poly(5'-acrylamido-5'-deoxy-1'-O-methyl-D-ribose) (13) were prepared as enzyme mimics. Polymers 12 and 13 with free vic-cis-diol groups catalyzed the hydrolysis of phosphodiester (ethyl p-nitrophenyl phosphate and N-methylpyridinium 4-tert-butylcatechol cyclic phosphate) and phosphomonoester substrates with a rate acceleration of 10 approximately equal to 10(3) compared with the uncatalyzed reaction. They also catalyzed the reverse reactions, i.e., the esterification of phosphomonoester to phosphodiester and the phosphorylation of alcohols with phosphate ions. The catalytic activity was attributable to the vic-cis-diols of riboses on polymer chains, which formed hydrogen bonds with two phosphoryl oxygen atoms of phosphates so as to activate the phosphorus atoms to be attacked by nucleophiles. The catalytic activity was negligible for polymer 11 where vic-cis-diol groups were blocked with isopropylidene groups. The catalytic activity was attributable to the vic-cis-diols of riboses on polymer chains, which formed hydrogen bonds with two phosphoryl oxygen atoms of phosphates so as to activate the phosphorus atoms to be attacked by nucleophiles.

Topics: Catalysis; Enzyme Inhibitors; Hydrolysis; Kinetics; Magnetic Resonance Spectroscopy; Models, Chemical; Molecular Structure; Organophosphates; Organophosphorus Compounds; Phosphates; Phosphorylation; Polymers; Potassium Compounds; Ribose; Sodium Acetate; Substrate Specificity; Time Factors

This study investigates the thermodynamics of the interaction of the TATA box binding protein (TBP) from Pyrococcus woesei (Pw) with an oligonucleotide containing a specific binding site. Pw is a hyperthermophilic archeal organism which exists under conditions of high salt and high temperature. A measurable protein-DNA interaction only occurs at high salt concentrations. Isothermal titration calorimetric binding studies were performed under a range of salts (potassium chloride, potassium phosphate, potassium acetate and sodium acetate) at varying concentrations (0.8 to 1.6 M). At the high salt concentrations used the observed equilibrium binding constant increases with increasing salt concentration. This is very different to the effect reported for all other protein-DNA interactions which have been studied at lower salt concentrations. Thermodynamic data suggest that the protein-DNA interaction at high salt concentration is accompanied by the removal of large numbers of water molecules from the buried hydrophobic surface area. In addition, the involvement of ions appears to influence the binding which can be explained by binding of cations in the interface between the electrostatically negative lateral lobes on the protein and the negatively charged DNA.

Topics: Amino Acid Sequence; Archaeal Proteins; DNA-Binding Proteins; Gene Expression Regulation, Archaeal; Genes, Archaeal; Molecular Sequence Data; Oligonucleotides; Osmolar Concentration; Phosphates; Potassium Acetate; Potassium Chloride; Potassium Compounds; Pyrococcus; Salts; Sequence Alignment; Sequence Homology, Amino Acid; Sodium Acetate; TATA-Box Binding Protein; Temperature; Transcription Factors