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Techniques are described for the semi-preparative isolation of sulfoquinovosyldiacylglycerol from plant leaf tissue lipid extracts and the resolution and analysis of component molecular species. Sulfoquinovosyldiacylglycerol was resolved from phospholipids in a polar lipid fraction by isocratic normal phase HPLC with detection at 208 nm. The mobile phase was composed of heptane-isopropanol-0.001 M KCl 40:52:8 (v/v/v). Yields from spinach leaf lipid extracts were 1.8 mg.10 g-1 fresh wt leaf tissue. Molecular species components of purified sulfoquinovosyldiacylglycerol were separated by reversed-phase C18 HPLC, and fatty acid positional distribution was defined.

Fossil records from sites overridden by or adjacent to the Laurentide Ice Sheet indicate that the climate of the last interglaciation (Oxygen-Isotope Substage 5e, ca. 130-116 ka) was warmer than today. Following the last interglaciation, the Laurentide Ice Sheet first developed during Stage 5 over Keewatin, Quebec and Baffin Island. Along its northern margin, the ice sheet reached its maximum extent of the last glaciation during Stage 5. The ice sheet advanced across Baffin Island onto the continental shelf early during Stage 5 (5d?), whereas the advance into the western Canadian Arctic occurred late during Stage 5 (5b?). The ice sheet also may have advanced into the St Lawrence Lowland during Substage 5b, although this event may be younger (Stage 4). The Hudson Bay lowland became ice-free during Substage 5a. Retreat of the ice sheet on Baffin Island occurred during late Stage 5, probably Substage 5a. The exact timing of retreat from the western Canadian Arctic is unknown, but it occurred before 48 ka. The southern sector, including the St Lawrence Lowland, was ice-free during late Stage 5. The Hudson Bay lowland may have remained ice free through Stage 4 and much of Stage 3. Because of conflicting chronologies, however, it is more likely that this area was glaciated throughout Stage 3 and perhaps Stage 4. Nevertheless, the data demonstrate that the lowland was ice-free during part of the last glaciation. An independent ice cap developed over the Appalachian Uplands and advanced across Nova Scotia during Stage 4, perhaps as far as the edge of the continental shelf. The ice cap remained active over Nova Scotia as a setellite to the Laurentide Ice Sheet throughout the remainder of the last glaciation. The ice sheet advanced into the St Lawrence Lowland during Stage 4 and subsequently overwhelmed the local ice cap in the Appalachian Uplands, advancing perhaps into northern New England, but not farther south. The Lowland remained covered by the ice sheet until late Stage 2. The ice sheet may also have advanced into the Lake Ontario basin during Stage 4. The position of the northern margin of the Laurentide Ice Sheet during Stage 4 is not known, but it remained an unknown distance behind its maximum position reached during Stage 5. Cores from Baffin Bay indicate a substantial decrease in high-latitude glaciation during Stage 4. Following retreat, the Keewatin sector of the ice sheet may have remained over much of northwestern Canada as a quasi-stable ice mass until it readvanced during Stage 2. Similarly, the Baffin Island sector of the ice sheet may have remained largely intact. The southern margin of the ice sheet may have advanced into the Lake Ontario basin and upper Mississippi Valley during the middle of Stage 3 (ca. 50 ka), reaching its maximum extent of the last glaciation during Stage 2 (ca. 18–21 ka). Advance of the northern margin was younger (ca. 8–13 ka) than that of the southern margin; this advance was less extensive than the penultimate advance (Stage 5). Paleoenvironmental records indicate that the last interglaciation in areas covered by and near the Cordilleran Ice Sheet was as warm as, or warmer than, present. The Cordilleran Ice Sheet appears to have developed during Stage 5 or 4. At that time, it advanced over southern British Columbia and into the northern Puget Lowland. There is no record of this event in northern areas that were later covered by the ice sheet. The ice sheet disappeared before 59 ka, at the beginning of a lengthy nonglacial interval. Paleoenvironmental records indicate that climate was similar to the present during part of this interval. The ice sheet was absent, and glaciers probably were confined to mountain areas, throughout Stage 3. Climatic deterioration marking the end of this nonglacial interval may have begun as early as 29 ka. By 14–15 ka, the ice sheet had achieved its maximum extent of the last glaciation. Because there are few suitable dating methods capable of resolving events beyond the radiocarbon limit and because sites that preserve a record of events from the last glaciation are spatially restricted, we consider this synthesis as tentative and subject to significant revision as dating methods improve. Nevertheless, this perspective of the North American ice sheets through the last glaciation demonstrates their complex and dynamic behavior and attendant rapid fluctuations in ice volume.

Clathrin, the major structural protein associated with both coated pits and coated vesicles, has been implicated in the dynamics of various endocytotic processes. In an attempt to define the mechanisms involved in the transition from uncoated membranes to clathrin-coated pits and then to coated vesicles, we investigated by infrared spectroscopy the lipid perturbations arising from the interactions of the clathrin coat with the bilayers of intact membrane assemblies. A comparison of the lipid acyl chain symmetric methylene stretching modes at approximately 2850 cm-1 for isolated clathrin-coated vesicles, uncoated vesicles, and synaptic membranes at 21, 38, and 50 degrees C indicated that clathrin significantly increases the number of gauche chain conformers in the bilayer matrix of the coated vesicle system. The increase in lipid disorder at 21 degrees C, accompanying the observed 0.44-cm-1 frequency increase for coated vesicles compared to uncoated vesicles, is approximately equivalent to the intrachain disorder incurred in heating liquid crystalline dimyristoylphosphatidylcholine multilayers by approximately 10 degrees C. The implications of these results on coated vesicle formation are discussed.

At the present time, eolian processes are active in many localities on Banks Island. Sediments of alluvial and outwash plains, as well as previously stabilized areas of eolian sands and areas where sandy Mesozoic and Tertiary deposits crop out, are subject to deflation. Locally ventifacts have been faceted.The vegetation cover of surfaces subject to eolian activity is described, as well as the main species observed on these surfaces.The eolian deposits of lower Thomsen River are described in detail. The study of a section has shown that ice-wedge polygons developed during periods of sand accumulation. The formation of segregation ice at the top of the permafrost, when it is raised because of the accumulation of eolian sands on the surface, is outlined.Two radiocarbon age determinations from two different sites along Thomsen River show that the deposition of eolian sands began 3790 ± 90 years BP (GSC-2119) and 3460 ± 80 years BP (GSC 2124). Ages of 5800 ± 180 years BP (GSC-2242) and 8430 ± 120 years BP (GSC-2419) were obtained respectively for the start of eolian sedimentation along Bernard River and on the outwash surface situated southeast of Sachs Harbour. The hypothesis that the initiation of eolian activity around 4000 years ago may have been the result of a drier and cooler climate on Banks Island is put forward.

A simple approach is presented whereby omega halogenated fatty acids can be obtained from macrocyclic musk lactones which are industrially available. While providing a secure source of 16-iodo-hexadecanoic acid and 17-iodo-heptadecanoic acid, the scheme allows ready access to a large number of untried fatty acid analogs. Examples presented are 16-iodo-hexadecanoic acid. 16-iodo-7-hexadecenoic acid. 16-iodo-12-oxa-hexadecanoic acid, 15-iodo-pentadecanoic acid, and 15-iodo-12-keto-pentadecanoic acid.

It would appear that the best method of the three investigated for preparing a labelled fatty acid to be used in nuclear cardiology is to autoclave an omega-brominated fatty acid in the presence of radioiodine, resuspend the labelled preparation in Tween 80∶D5W: propylene glycol (10∶80∶10) and sonicate it for 30 minutes. Care must be taken when injecting Tween although no adverse effects were noted during the present study.

The Duck Hawk Bluffs, of southwestern Banks Island in the Canadian Arctic Archipelago, record a succession of late Tertiary – Quaternary events. Organic-bearing sediments of eolian, fluvial, and lacustrine origin that overlie the Late Cretaceous Kanguk Formation and the Miocene Beaufort Formation record preglacial events of Pliocene and (or) early Quaternary age and are assigned to the Worth Point Formation. These are covered by glacial sediments of the Duck Hawk Bluffs Formation associated with the Banks Glaciation, the oldest of the three recognized glaciations to reach the island. Associated with the glacial deposits are marine or glaciomarine sediments deposited in the glacio-isostatically depressed area as the ice both advanced and retreated. These sediments are in turn covered by interglacial sediments (Morgan Bluffs Formation), by marine deposits (Big Sea sediments associated with the Thomsen Glaciation), and by younger interglacial sediments (Cape Collinson Formation). Events associated with the early Wisconsinan M'Clure Stade of the last or Amundsen Glaciation are recorded in a coastal section east of the Duck Hawk Bluffs. There, marine deposits (pre-Amundsen Sea sediments) are covered by glacial deposits (Sachs Till) of the M'Clure Stade, D/L ratios of aspartic acid in fossil wood from the Morgan Bluffs and Cape Collinson interglacial sites, respectively, vary between 0.22 and 0.31 and 0.12 and 0.13, while Holocene wood is 0.08. A composite section is proposed for these bluffs that record some of the oldest events in the Canadian Quaternary and the various units are correlated with the previously published Quaternary framework for Banks Island.

An attempt has been made at dating Middle and Late Pleistocene deposits from Banks and Victoria islands using the Th–U disequilibrium method. Geological correlations are difficult to establish because of the discontinuous nature of the terrestrial units and the relative absence of datable fossil wood and shells. The Th–U geochemical system likely remained closed for extended periods because of the presence of permafrost, which implies very limited or absent water circulation. The Th–U age determinations obtained confirmed the previously established stratigraphic framework and provide chronological information in that samples of Sangamonian age are differentiated from those that are younger (Wisconsinan and Holocene) or older (Middle Pleistocene). The Th–U disequilibrium method carefully used in areas where water circulation is limited can thus provide chronological control for sediments older than those that can be dated by the radiocarbon method.

Study of the elastic scattering of 600-MeV protons from light nuclei. Differential cross sections have been obtained for the scattering of protons from hydrogen, deuterium, helium-3, and helium-4. Polarization was measured for deuterium and He-4 nuclei. The p-p cross-section data are in excellent agreement with the predictions from the Livermore phase shifts. Small-angle p-D, p-He-3 elastic scattering data are compared with calculations based on the multiple-scattering theories of Watson and Glauber.

The differential cross section for elastic scattering of 42 MeV α-particles from 3 He has been measured between 20° and 160° c.m. A phenomenological description of the elastic scattering data is given by an optical-model calculation. To reproduce the shape of the differential cross section it was found that the absorptive potential was required to extend radially beyond the real potential. Including a small spin-orbit potential in the calculation improves the agreement with the experiment and predicts a polarization which is consistent with one measurement at a nearby energy. The reaction cross section given by the optical-model calculation is close to a lower limit estimated from integration of inelastic events observed. The two-body reactions 3 He(α, p) 6 Li ground and first excited state, were measured between 20° and 160° c.m. Optical potentials determined from elastic scattering data were used in a distorted wave Born approximation prediction for these cross sections. Qualitative agreement was obtained assuming only the 3 He stripping mode.

Proton-deuteron elastic large angle scattering cross sections, noting backward peak consistent with baryon exchange mechanism with resonance transfer

The differential cross section for elastic scattering of 600-MeV protons from $^{4}\mathrm{He}$ has been measured for laboratory angles between 4\ifmmode^\circ\else\textdegree\fi{} and 44\ifmmode^\circ\else\textdegree\fi{}. The data are analyzed in terms of the diffraction approximation of Glauber.

Cross sections measured for symmetric /p, 2p/ reactions on deuterium and He, discussing nonsymmetric /p, 2p/ events in He

Thirteen angular distributions have been measured from 8\ifmmode^\circ\else\textdegree\fi{} to 70\ifmmode^\circ\else\textdegree\fi{} for the ${\mathrm{Sc}}^{45}(\ensuremath{\alpha},t){\mathrm{Ti}}^{46}$ reaction at 41 MeV. Very selective population of the states of ${\mathrm{Ti}}^{46}$ was observed, and the populated states correlate well with states of the ${\mathrm{Sc}}^{45}({\mathrm{He}}^{3},d){\mathrm{Ti}}^{46}$ reaction which have large ${l}_{p}=3$ spectroscopic strengths. The angular distributions have little structure and exhibit the same basic shape. The distorted-wave Born-approximation (DWBA) noncutoff calculations for the stripping of an ${l}_{p}=3$ proton provides an adequate description of the angular distributions. The relative spectroscopic strengths extracted from the DWBA analysis agree favorably with those deduced from a similar study of the ${\mathrm{Sc}}^{45}({\mathrm{He}}^{3},d){\mathrm{Ti}}^{46}$ reaction. Theoretical spectroscopic strengths calculated from the McCullen-Bayman-Zamick single-particle wave functions for the ground state of ${\mathrm{Sc}}^{45}$ and five low-lying states of ${\mathrm{Ti}}^{46}$ are in reasonable agreement with experiment.

Asymmetry of polarized protons scattered from He 4 at 540 Mev for laboratory angles between 4 and 42 degrees

High energy proton-He 3 elastic scattering cross section measurement, comparing result with Glauber model calculation

An external beam-bunch selector has been built to modulate the beam of the NASA 60-inch cyclotron for neutron time-of-flight studies. Electrostatic deflection at one-fourth the cyclotron frequency is used to lengthen the beam burst period, so that longer flight times can be used. The design and performance of this apparatus are described. With this equipment, flight times up to 400 nanoseconds are available, without distortion of the cyclotron beam burst width. Energy resolutions of the order of 2 percent are thus possible.

The differential cross sections for inelastic alpha particle scattering to large angles from 3+ states in 24Mg and 26Mg at 42 MeV show a clear diffraction type of pattern and pronounced enhancement compared with forward angles.

A liquid cesium target has been developed which allows the production and separate identification of the neutron deficient isotopes of xenon. The present report describes irradiations utilizing 34--41 MeV protons to produce millicurie quantities of 127Xe and 129Xem. At higher energies, however, the target could be used without modification to produce xenon isotopes as light as 119.

The cyclotron is routinely operated with three simultaneously extracted beams and more are planned. A double beam has been sent down one line with sufficient separation for magnetic splitting. The extracted beam intensity can now be continuously varied from 103 to 1015 protons/s (170 ?A). The highest intensities were obtained by the addition of a second harmonic buncher in the injection beam line. Direct measurements of the electromagnetic H- stripping losses agree with those expected. Beam-defining slits have been used to reduce the energy spread (?E/E) of the extracted beam to 10-3 at all energies between 200 and 500 MeV. Under certain circumstances the medium resolution spectrometer has measured a resolution a factor of two better. Depolarizing resonances have been located and one of them corrected. A number of new experimental facilities have been commissioned recently. These include a low intensity polarized proton line operating to a polarized target, a high luminosity, low energy ?-? channel, and a clean cloud or surface muon channel using a velocity separator. The influence of the beam size and target shape on the characteristics of secondary particles has been examined.