Seven liquid solvent systems--dichloromethane, dichloromethane-pentane (1:1), freon 113, diethyl ether-pentane (1:1 and 1:9), ethyl acetate-pentane (with and without an additional salting-out effect) (1:3 and 1:20), and seven solid-phase extraction (SPE) systems (Amberlite XAD-2, 4, 7, and 16; Porapak Q; C8; and C18)--are comparatively studied. The distribution coefficients between the extracti...

A large number and variety of compounds are formed in the process of chlorinating drinking water. The classes of compounds formed include trihalomethanes, haloacetic acids, haloacetonitriles, halophenols, and halopropanones. Many of the compounds have been shown to be toxic and are currently being further evaluated by the U.S. Environmental Protection Agency (EPA). One group of the halopropanon...

The eye lens crystallins represent an ideal target for studying the effects of aging on protein structure. Herein we examine separately the water-soluble (WS) and water-insoluble (WI) crystallin fractions and identify sites of isomerization and epimerization. Both collision-induced dissociation and radical-directed dissociation are needed for detection of these non-mass-shifting post-translatio...

Femtosecond time-resolved absorption measurements were performed to investigate the influence of the pH, imidazole concentration, and point mutations on the isomerization process of Channelrhodopsin-2. Apart from the typical spectral characteristics of retinal isomerization, an additional absorption feature rises for the wild-type (wt) on a timescale from tens of ps to 1 ns within the spectral ...

BACKGROUND Volatile breath biomarkers provide a non-invasive window to observe physiological and pathological processes in the body. This study was intended to assess the impact of heart surgery with extracorporeal circulation (ECC) onto breath biomarker profiles. Special attention was attributed to oxidative or metabolic stress during surgery and extracorporeal circulation, which can cause org...

Biodiesel extracted from Scenedesmus obliquus algae through transesterification was used in the current study. Due to disadvantages of using pure biodiesel engines, it as B50 (a blend 50% diesel and biodiesel). To enhance engine performance, n-pentane different extents 5, 10, 15 ml per liter an enhancer additive. Through performance tests, found that best addition caused increase brake thermal ...

Abstract The structurally related cobalt β‐diketonate complexes Co(acac) 2 , ⋅ TMEDA, Co(tfac) and Co(hfac) TMEDA (acac=2,4‐pentanedionate, tfac=1,1,1‐trifluoro‐2,4‐pentane‐dionate, hfac=1,1,1,5,5,5‐hexafluoro‐2,4‐pentane‐dionate, TMEDA= N ′, ′‐tetramethylethylenediamine) were thermochemically (thermogravimetric analysis, differential scanning calorimetry) spectroscopically (infrared, UV‐VIS el...

The degradation of proteins by asparagine deamidation and aspartate isomerization is one of several chemical degradation pathways for recombinant antibodies. In this study, we have identified two solvent accessible degradation sites (light chain aspartate-56 and heavy chain aspartate-99/101) in the complementary-determining regions of a recombinant IgG1 antibody susceptible to isomerization und...

The planar isomerization routes of the vinylidene/acetylene cation in the lowest electronic states are accurately examined for the first time, by using large scale MRCI and CCSDT calculations in a complementary way. They are compared with the similar calculations performed for the neutral ground state isomerization. An accurate value of the adiabatic ionization potential of vinylidene (11.26 eV...

in the 1970 s, regulations in some counries forced usersof heavy residue to limit pollutant emissions at industrial sites, also forced producers to up grade their heavy products for export and domestic use. for this reason iran as a producer, exporter and consumer has to develop mew upgrading processes.the most common processes for upgrading heavy oil are catalytic processes, but existence of h...