Enantioselectivity of 6-O-alkyldimethylsilyl-2,3-di-O-methyl-β-cyclodextrins as chiral stationary phases in capillary GC

Summary Clenbuterol has been determined in urine by solidphase extraction on a C₁₈ cartridge, diazotization of the eluate with nitrite, coupling of the diazonium ion with 1-(naphthyl)ethylenediamine, and separation of the azo dye formed by HPLC with a C₁₈ column and a micellar mobile phase containing 0.1 M sodium dodecyl sulphate, 12%n-butanol and 0.05 M citrate buffer, pH 3. Recoveries higher than 90% were obtained by mixing the samples with a 20% 0.2 M NaOH before extraction. Limits of detection of 51 and 6.7 ng L⁻¹ were obtained with spectrophotometric and thermal lens spectrometric detection, respectively; respective repeatabilities were 3.1% (5 μg mL⁻¹) and 5.6% (0.16 μg mL⁻¹).     

Functionalization of the 4(5)methyl group of imidazoles: A novel synthesis of substituted imidazoles

Acyl vinyl phosphonium salts react with amidines to form imidazolyl phosphonium salts. These imidazolyl salts can be readily converted to multifunctional imidazoles with quantitative recovery of triphenyl phosphine.     

Chlorpromazine hydrochloride as an analytical reagent : A new indicator for titrations with very dilute ceric sulphate solutions

Chlorpromazine hydrochloride is proposed as an indicator for the microtitration of iron(II), arsenic(III), ascorbic acid and hydroquinone with 0.0005–0.001 N ceric sulphate; the indicator blanks are small. The colorimetric déterminations of μg quantities of cerium(lV) and arsenic(III) using the same reagent are also described.     

The direct conversion of carbamates to ureas using aluminum amides

The conversion of carbamates into ureas using aluminum amide complexes is reported. This reaction is a convenient method to prepare bi-, tri- and tetra-substituted ureas from carbamate-protected primary or secondary amines by reaction with primary or secondary amines in the presence of stoichometric quantities of trimethylaluminum. A reactivity trend of the various carbamates was observed and methyl and benzyl carbamates were reacted selectively in the presence of t-butyl carbamates.     

The use of a chelating resin column for preconcentration of trace elements from sea-water in their determination by neutron-activation analysis

A Chelex-100 resin column has been employed for the preliminary concentration of trace elements in water samples before their determination by neutron-activation analysis. The column, filled with a 1:1 mixture of the resin (50-100 mesh) and Pyrex glass powder of the same mesh-size, is shown to maintain a constant flow-rate and give reproducible results. By a combination of preconcentration and neutron-activation analysis it is possible to determine Ba, Ca, Cd, Ce, Co, Cr, Cu, Fe, La, Mg, Mn, Sc, U, V and Zn in sea-water and/or fresh water simultaneously at the parts per milliard level.     

The preparation,isomerization, and characterization of some phosphagerma- and arsagermacarboranes

Treatment of the disodium salts of 7,8- and 7,9-B₉H₉CHE^2? with germanium diiodide in refluxing benzene results in the formation of 1,2,3- and 1,2,7-GeB₉H₉CHE (E = P or As), icosahedral boranes containing three different heteroatoms in the cage. Heating 1,2,7-GeB₉H₉CHP at 512° for 8 hours in an evacuated sealed tube yields a mixture of three new isomers one of which has been isolated and characterized.     

Direct electrochemical assay of glucose using boron-doped diamond electrodes

We report linear sweep and square wave voltammetric studies on glucose oxidation at boron-doped diamond (BDD) electrodes in an alkaline medium in efforts to evaluate the techniques for electrochemically assaying glucose. The bare BDD electrode showed good linear responses to glucose oxidation for a concentration range from 0.5 to 10 mM glucose, which well encompasses the physiological range of 3-8 mM. The BDD electrodes did not experience interferences from ascorbic acid or uric acid during glucose detection. This method, when applied to real blood samples, gave results similar to those obtained by a commercial glucose monitor.     

Kinesin superfamily protein member 4 (KIF4) is localized to midzone and midbody in dividing cells

In association with microtubules, a variety of kinesins play important roles in cellular functions such as intracellular transport of organelles or vesicles, signal transduction, and cell division. In a previous study we revealed that human kinesin superfamily protein member 4 (KIF4) is a chromokinesin that binds to chromosomes. Since localization of several kinds of kinesin at midzone called central spindle, or midbody that connects two daughter cells, or both, suggests their implication in cell division, we investigated KIF4 localization of during mitosis and cytokinesis in Hela cells. In addition to association with segregating chromosomes through entire mitosis, it also localized to the midzone and to midbody at ana/telophase through cytokinesis. Especially in cells at cytokinesis, KIF4 appeared as a doublet facing each other at the apical ends of two daughter cells. Three- dimensional analysis of architectural relationship between microtubule bundles and KIF4 indicated that KIF4 forms a ring structure wrapping around the microtubule bundles. These results suggest that KIF4 is involved in cytokinesis, although direct evidence was not provided in this study.     

Spectroscopy with sound on superfluid 3He B

Collective modes of superfluid ³He B have been studied by means of sound attenuation and sound velocity studies. A new sound attenuation peak has been observed in superfluid ³He B at ?ω ≈ Δ(T). This peak has been identified with the real squashing mode. Pulse time of flight methods has been used in these studies. At high sound amplitudes, interesting transient effects have been observed which have been tentatively identified with solitonlike behavior.     

On the constancy of the velocity of light

We point out that the acceptance of the relativity principle together with the homogeneity and isotropy of space and the homogeneity of time inevitably leads to the Lorentz spacetime transformation with a universal limiting speed . Speculations on possible new four-dimensional symmetries involving a variable speed of light such as that proposed by Hsu must therefore be dismissed on such a basis alone. In this paper we draw attention to some logical inconsistencies in Hsu's attempt at establishing a new space-light transformation law, and follow with a discussion on why such an attempt must necessarily fail.