On Vassiliev knot invariants induced from finite type 3-manifold invariants

We prove that the knot invariant induced by a -homology 3-sphere invariant of order in Ohtsuki's sense, where , is of order . The method developed in our computation shows that there is no -homology 3-sphere invariant of order 5.

     

Palladium-Catalyzed Carbo-Oxygenation of Propargylic Amines using in Situ Tether Formation

1,2-Amino alcohols and α-aminocarbonyls are frequently found in natural products, drugs, chiral auxiliaries, and catalysts. This work reports a new method for the palladium-catalyzed oxyalkynylation and oxyarylation of propargylic amines. The reaction is perfectly regioselective based on the in situ introduction of a hemiacetal tether derived from trifluoroacetaldehyde. cis-Selective carbo-oxygenation was achieved for terminal alkynes, whereas internal alkynes gave trans-carbo-oxygenation products. The obtained enol ethers could be easily transformed into 1,2-amino alcohols or α-amino ketones using hydrogenation or hydrolysis, respectively.     

Half-life and gamma abundance ratio measurements of 153Sm

The measurement of the decay of ¹⁵³Sm was observed by gamma spectrometry, liquid scintillation counting and gas proportional counting in an attempt to confirm the half life and gamma abundance ratios for this isotope. Recent changes in the published nuclear decay data indicate that historical literature values may be biased. The ¹⁵³Sm was made by the neutron activation of ultra-pure isotopically enriched ¹⁵²Sm to create ¹⁵³Sm. The decay measurements were made over a three week period and no other isotopes were detected during this time. The gamma abundance ratio for the 103 keV gamma was measured to be (27.9%) which is 4% lower than the published data. In addition, the half life was 1.9308 days, which is 0.34% lower than the published data.     

Potential applications of passive sampling for monitoring non-polar industrial pollutants in the aqueous environment in support of REACH

Possible roles of passive sampling within the context of the European REACH legislation are discussed. Passive samplers can provide information on environmental concentrations, fate and behaviour of substances of concern. They can potentially replace biota in the assessment of bioavailability, having advantages including lower cost and variability, and greater repeatability and acceptability on ethical grounds. Where remedial actions (e.g., product withdrawal, replacement or redesign) may be required, wrong decisions are potentially very costly. Against this background it may be possible to develop strategies based on passive sampling that will protect the environment from potential damage whilst minimising operational costs.     

The transition-metal assisted synthesis of the anti-octadecaborate Anion [B18H21] from the Nido-dodecahydrononaborate anion [B9H12]

When heated under reflux in CH₂Cl₂ solution with [Os(CO)₃Cl₂]₂, two nido-[B₉H₁₂]⁻ units edge-fuse to form anti-[B₁₈H₂₁]⁻.     

Construction of a shallow underground low-background detector for a CTBT radionuclide laboratory

The International Monitoring System is a verification component of the Comprehensive Nuclear-Test-Ban Treaty, and in addition to a series of radionuclide monitoring stations, contains 16 radionuclide laboratories capable of verification of radionuclide station measurements. This paper presents an overview of a new commercially obtained low-background detector system for radionuclide aerosol measurements recently installed in a shallow (>30 meters water equivalent) underground clean-room facility at Pacific Northwest National Laboratory. Specifics such as low-background shielding materials and active shielding methods will be covered.     

Quantum: Einstein,Bohr and the Great Debate About the Nature of Reality,by Manjit Kumar

The history of absolute measurements of gravity is mentioned and the reasons for making absolute measurements are indicated. The principles and main advantages and difficulties of the main method—reversible pendulum, free fall, symmetrical free motion—are discussed and examples of each method are described. Problems of comparison of different determinations and of estimating systematic errors are considered.     

Surface Roughness and Contact: An Apology

The Greenwood and Williamson theory of contact has been widely accepted, and perhaps does contain the essential feature needed: that asperities should have a height distribution which approximates to a simple exponential in the relevant range of heights. The Gaussian height distribution often found experimentally does indeed approximate to an exponential as required. It appears that Greenwood and Williamson's second assumption, that asperities may be treated as having spherical caps and as being identical except for their heights, is also useful: little is gained by treating the asperities as ellipsoids, or by introducing a distribution of asperity sizes. But a third, tacit, assumption, that 'peaks' on a surface profile – points higher than their immediate neighbours at the sampling interval used – correspond to asperities is quite wrong, and gives a false idea of both the number and the radius of curvature of the asperities. Instead we need to return to the earlier Archard concept that roughness consists of 'protuberances on protuberances on protuberances', and perhaps also to another Archard idea, the paradox that contact may be plastic at light loads but become elastic at heavier loads!     

The direct gas chromatographic analysis of barbiturates as their sodium salts.

The addition of formic acid to the carrier gas will permit the on-column liberation of the free acids following the direct injection of barbiturates as their sodium salts. These free acids may then be resolved upon an Apiezon L column: the presence of formic acid also minimizes the adsorption effects which may be associated with the gas chromatographic analysis of these relatively polar drugs.