The present work investigates hydrate equilibrium conditions for tetra-n-butyl ammonium bromide (TBAB) + methane + water mixtures. The experiments are carried out in the TBAB mass fraction range of (0.05 to 0.45) and in the pressure range of (0.5 to 7.0) MPa. The experimental results show that the presence of TBAB decreases the formation pressure of methane hydrate. Moreover, pressure reduction is dependent on the TBAB concentration.

Plasma is recognized as a promising source of disease-related biomarkers, and proteomic approaches for identifying novel plasma biomarkers are in great demand. However, the complexity and dynamic protein concentration range of plasma remain the main obstacles for current research in this field. In this study, plasma proteins were prefractioned by immunodepletion and Protein Equalizer Technology to remove high abundant proteins, then labeled with an 8-plex isobaric tags for relative and absolute quantitation (iTRAQ) to improve the peptide ionization, and analyzed by strong-cation-exchange(SCX) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our results showed that both prefraction methods were complementary, with regard to the number of identified proteins. Good chromatographic technique is important to further fractionate the iTRAQ labeling peptides, which allowed 320 and 248 different proteins to be characterized from two prefraction methods, respectively, encompassing a wide array of biological functions and a broad dynamic range of 10(7). Furthermore, the accuracy of iTRAQ relative quantitation for differentially expressed proteins is associated with the number of peptides hits per protein.

Cross-linked enzyme aggregates (CLEAs) have been recently proposed as an alternative to conventional immobilization methods on solid carriers. However, the low cross-linking efficiency causes the major activity loss and instability in the conventional protocol for CLEA preparation. Herein, the effects of bovine serum albumin and starch addition on the cross-linking efficiency of CLEAs of phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis were evaluated. A co-aggregation strategy was developed to improve cross-linking efficiency by adding starch and bovine serum albumin (BSA). CLEAs of PAL prepared in the presence of BSA and starch (PSB-CLEAs) retained 36 % activity, whereas CLEAs prepared without BSA and starch (PAL-CLEAs) retained only 8 % activity of the starting enzyme preparation. Compared with PAL-CLEAs, the thermal stability of PSB-CLEAs has improved considerably, maintaining 30 % residual activity after 4 h of incubation at 70 °C, whereas the PAL-CLEAs have only 13 % residual activity. PSB-CLEAs also exhibited the expected increased stability of PAL against hydrophilic organic solvents, superior operability, and higher storage stability. The proposed technique of preparing CLEAs using co-aggregation with starch and BSA would rank among the potential strategies for efficiently preparing robust and highly stable enzyme aggregates.

The prediction of the solubilities of carbon dioxide and methane in aqueous solutions of inorganic salts is important for geological carbon storage, enhanced oil recovery, gas hydrate formation and seawater desalination. Few electrolyte equations of state can be used for accurate gas solubility calculations over wide ranges of temperature, pressure and salt molality. This work presents a thermodynamic modeling study on the solubilities of carbon dioxide and methane in aqueous solutions of several inorganic salts with the electrolyte Cubic-Plus-Association equation of state. The binary interaction parameters between ion and gas are obtained by fitting the experimental data of gas solubility in single-salt solutions. It is shown that the equation of state can satisfactorily correlate the gas solubility over a wide range of conditions, with deviation less than the reported experimental uncertainties (7%) for most systems. The equation of state is then used to predict the gas solubility in multi-salt solutions, and a satisfactory performance is achieved. The saltingout effects resulting from ion size, charge density, and salt concentration are also extensively discussed.

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