Electrochemically triggered upconverted luminescence for light-emitting devices.

Electrochemically triggered upconverted luminescence through triplet-triplet energy transfer (TTET) and subsequent triplet-triplet annihilation upconversion (TTA-UC) is observed for the first time in the electrochemiluminescence properties of a Ru(bpy)32+/DPA-containing electrochemical device.

Effect of sequential C-terminal tryptophans on green fluorescent protein fluorescence.

The effect of the addition of sequential C-terminal tryptophan residues on the fluorescence intensity of GFP was investigated. Tandem repeats of six tryptophan residues markedly decreased fluorescence intensity. This phenomenon is likely to occur because of the inhibition of GFP folding, resulting in insolubility.

A rapid and sensitive chiral LC-MS/MS method for the determination of ketamine and norketamine in mouse plasma, brain and cerebrospinal fluid applicable to the stereoselective pharmacokinetic study of ketamine.

A novel method for the rapid and sensitive chiral determination of ketamine and norketamine in mouse plasma, brain and cerebrospinal fluid (CSF) was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method reduces the required matrix volume, compared with a previously reported chiral assay method for ketamine and norketamine. The method involves the deproteinization of a small amount of biological matrix (corresponding to 5μL of plasma, 10mg of brain, or 2.

Recommendation to Exclude Bile-Duct-Cannulated Rats with Hyperbilirubinemia for Proper Conduct of Biliary Drug Excretion Studies.

Hyperbilirubinemia (HB) is sometimes encountered following bile-duct cannulation in rats. It possibly originates from the reduced functioning of multidrug resistance-associated protein 2 (Mrp2) and subsequent adaptive alterations in the expression of Mrp3 and the organic anion transporting polypeptides (Oatps). Our aim was to clarify the importance of excluding bile-duct-cannulated (BDC) rats with HB for proper conduct of drug excretion studies.

Synthesis of thiiranes by rhodium-catalyzed sulfur addition reaction to reactive alkenes.

A rhodium complex derived from RhH(PPh3)4, dppe, and 4-ethynyltoluene catalyzes the addition reaction of sulfur to norbornenes giving the corresponding thiiranes under acetone reflux conditions. The rhodium complex effectively transfers a sulfur atom to the double bond from sulfur, and exo-adducts are obtained. The reaction is also applicable to (E)-cyclooctene and cyclic allenes.

Rhodium-catalyzed synthesis of diaryl sulfides using aryl fluorides and sulfur/organopolysulfides.

Substituted pentafluorobenzenes react with sulfur to give bis(4-substituted 2,3,5,6-tetrafluorophenyl) sulfides in the presence of RhH(PPh(3))(4), 1,2-bis(diphenylphosphino)benzene (dppBz), and tributylsilane. The reaction proceeds efficiently between room temperature and 80 °C. A comparative study of the reactivities of an organic trisulfide and a tetrasulfide showed notable substrate specificity.

Focal brain cooling terminates the faster frequency components of epileptic discharges induced by penicillin G in anesthetized rats.

Objective: The goal of the study was to investigate the effects of focal brain cooling on epileptic discharges (EDs) and background rhythms in the sensorimotor cortex of anesthetized rats using spectral analysis of electroencephalography (EEG).

Methods: Penicillin G was administered intracortically into superficial layers of the left sensorimotor cortex and EDs were induced. Focal brain cooling was achieved using a cooling device attached to the cortical surface.

Stable isotope-dilution liquid chromatography/tandem mass spectrometry method for determination of thyroxine in saliva.

A liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for the determination of thyroxine (T(4)) in human saliva has been developed and validated. The saliva was deproteinized with methanol, purified using a Strata-X™ cartridge, and subjected to LC/ESI-MS/MS. Quantification was based on selected reaction monitoring, and [(13)C(6)]-T(4) was used as the internal standard.

Simple and practical derivatization procedure for enhanced detection of carboxylic acids in liquid chromatography-electrospray ionization-tandem mass spectrometry.

A simple and practical derivatization procedure for increasing the detection responses of carboxylic acids in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) has been developed. 2-Hydrazinopyridine (HP) and 2-picolylamine (PA) rapidly reacted with biologically and clinically important carboxylic acids [chenodeoxycholic acid, glycochenodeoxycholic acid, prostaglandin E2, 2-(-carboxyethyl)-6-hydroxy-2,7,8-trimethylchroman (gamma-CEHC),alpha-lipoic acid, homovanillic acid (HVA) and 5-hydroxyindole-3-acetic acid] in the presence of 2,2'-dipyridyl disulfide and triphenylphosphine. The resulting HP- and PA-derivatives were highly responsive in ESI-MS operating in the positive-ion mode and gave characteristic product ions during MS/MS, which enabled the sensitive detection using selected reaction monitoring.

Salivary chenodeoxycholic acid and its glycine-conjugate: their determination method using LC-MS/MS and variation of their concentrations with increased saliva flow rate.

Measurement of steroid levels in saliva has been proposed as a new laboratory tool for characterizing steroid metabolism, but it is not known whether the salivary levels of bile acids can be measured with accuracy and if so, whether such measurements provide information that is of clinical value. We developed and validated a sensitive and specific liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-ESI-MS/MS) method for the quantification of chenodeoxycholic acid (CDCA) and glycochenodeoxycholic acid (GCDCA), representative primary non-amidated and glycine-conjugated bile acids, in whole saliva. We also examined whether the salivary bile acid concentrations were dependent on the saliva flow rate, because this is a very important aspect in a discussion of the utility of salivary diagnostics.