Optimal elution modes were determined for four typical two-phase solvent systems each with different physical parameters to achieve the best peak resolution and retention of the stationary phase by spiral tube high-speed countercurrent chromatography using a suitable set of test samples. Both retention of the stationary phase and partition efficiency are governed by an interplay between two forces, i.e., Archimedean Screw force and radial centrifugal force gradient of the spiral channel. In the polar solvent system represented by 1-butanol./acetic acid/water (4:1:5, v/v/v) with settling time of over 30 s, the effect by the radial centrifugal gradient force dominates giving the best separation of dipeptides either by pumping the lower phase from the inner terminal or the upper phase from the outer terminal of the spiral channel. In the moderately hydrophobic two-phase solvent system represented by hexane/ethyl acetate/methanol/0.1 M HCl (1:1:1:1) with settling time of 19 s, and two hydrophobic solvent systems of hexane/ethanol/water (5:4:1, v/v/v) and non-aqueous binary system of hexane/acetonitrile both having settling time of 9, the effect of the Archimedean screw force play a major role in hydrodynamic equilibrium, giving the best separations by pumping the lower phase from the head or the upper phase from the tail of the spiral channel.

The original spiral tube support (STS) assembly is improved by changing the shape of the tubing, with 1-cm presses perpendicularly along the length. This modification interrupts the laminar flow of the mobile phase. The tubing in the 4 return grooves to the center of the rotor is flattened by a specially made pressing tool to decrease the dead volume and thus increase the column efficiency. The performance of this spiral tube assembly was tested in separations of dipeptides and proteins with suitable polar two-phase solvent systems. The results revealed that the present system yields high partition efficiency with a satisfactory level of stationary phase retention in a short elution time. The present high-speed counter-current chromatographic system will be efficiently applied to a broad spectrum of two-phase solvent systems including aqueous-aqueous polymer phase systems which are used for separation of biopolymers such as proteins and nucleic acids. . Keywords spiral tube support assembly; high-speed counter-current chromatography; Separation of proteins and peptides; polymer phase system (TPAS)

For many years, high-speed countercurrent chromatography conducted in open tubing coils has been widely used for the separation of natural and synthetic compounds. In this method, the retention of the stationary phase is solely provided by the Archimedean screw effect by rotating the coiled column in the centrifugal force field. However, the system fails to retain enough of the stationary phase for polar solvent systems such as the aqueous-aqueous polymer phase systems. To address this problem, the geometry of the coiled channel was modified to a spiral configuration so that the system could utilize the radially acting centrifugal force. This successfully improved the retention of the stationary phase. Two different types of spiral columns were fabricated: the spiral disk assembly, made by stacking multiple plastic disks with single or four interwoven spiral channels connected in series, and the spiral tube assembly, made by inserting the tetrafluoroethylene tubing into a spiral frame (spiral tube support). The capabilities of these column assemblies were successfully demonstrated by separations of peptides and proteins with polar two-phase solvent systems whose stationary phases had not been well retained in the earlier multilayer coil separation column for high-speed countercurrent chromatography.

A novel counter-current chromatographic system is developed by mounting a vortex column on a type-I coil planet centrifuge. The column is fabricated from a high-density polyethylene disk (16 cm diameter and 5 cm thick) by making multiple holes of various diameters (3-12.5 mm) each arranged in a circle and connected with narrow transfer ducts. The performance of this vortex column is tested with three different two-phase solvent systems with a broad range in hydrophobicity. The results indicated that the smallest diameter column (3 mm diameter, 120 units with 42.8 ml capacity) yielded the best separation with the height equivalent to a theoretical plate of 2 cm compared with 20 cm required by the conventional multilayer coil column of high-speed CCC. By avoiding the use of an Archimedean Screw force, the system shows a low column pressure which would permit safe operation of a large preparative column without a risk of leakage of solvent and column damage.

Significant interest exists in strategies for improving forelimb function following spinal cord injury. We investigated the effect of enriched housing combined with skilled training on the recovery of skilled and automatic forelimb function after a cervical spinal cord injury in adult rats. All animals were pretrained in skilled reaching, gridwalk crossing, and overground locomotion. Some received a cervical over-hemisection lesion at C4-5, interrupting the right side of the spinal cord and dorsal columns bilaterally, and were housed in standard housing alone or enriched environments with daily training. A subset of animals received rolipram to promote neuronal plasticity. Animals were tested weekly for 4 weeks to measure reaching, errors on the gridwalk, locomotion, and vertical exploration. Biotinylated dextran amine was injected into the cortex to label the corticospinal tract. Enriched environments/daily training significantly increased the number and success of left reaches compared to standard housing. Animals also made fewer errors on the gridwalk, a measure of coordinated forelimb function. However, there were no significant improvements in forelimb use during vertical exploration or locomotion. Likewise, rolipram did not improve any of the behaviors tested. Both enriched housing and rolipram increased plasticity of the corticospinal tract rostral to the lesion. These studies indicate that skilled training after a cervical spinal cord injury improves recovery of skilled forelimb use (reaching) and coordinated limb function (gridwalk) but does not improve automatic forelimb function (locomotion and vertical exploration). These studies suggest that rehabilitating forelimb function after spinal cord injury will require separate strategies for descending and segmental pathways.

A volumetric approach was used to estimate in-place gas in the Upper Cretaceous through lower Tertiary age basin-centered, low-permeability gas accumulation in the Wind River Basin of central Wyoming. The accumulation was subdivided into a total of 22 plays. Eight different stratigraphic units were considered. These units were then subdivided into as many as three plays based on variations in thermal maturity, presentday formation temperatures, and in the case of the lower member of the Paleocene Fort Union Formation, the presence or absence of an overlying shale seal. Highly overpressured plays occur where present-day formation temperatures exceed 300° F. Pressure gradients in these plays average about 0.73 pound per square inch per foot of depth (psi per ft). Moderately overpressured plays (0.52 psi/ft average pressure gradient) occur where present-day thermal maturity using vitrinite reflectance is 1.1% or greater. Transition plays occur where present-day vitrinite reflectance values are between 1.1% and 0.73%. These plays include a combination of tight gas reservoirs, gas reservoirs with conventional permeabilities, and water-bearing reservoirs,The lower member of the Paleocene Fort Union Formation, the stratigraphically youngest unit included in the basin-centered gas accumulation, is unique in that gas occurs where thermal maturates are as low as a vitrinite reflectance of 0.5 to 0.6%. The overlying lacustrine Waltman Shale Member of the Fort Union Formation appears to be acting as a seal inhibiting the vertical migration of gas out of the basin-centered accumulation. The lower member was divided into two plays, the first where the overlying Waltman Shale is present, and the second where the lacustrine shale has been replaced marginward by deltaic and fluvial deposits. The seal is assumed to be absent in the second play.A combination of overburden maps and isopach maps of total sandstone in beds 10 ft thick or greater is used to subdivide each play into as many as 120 subplay areas, each with a unique sandstone thickness and average depth. Point estimates were made of each attribute for each subplay using the maps, and a point estimate or mean estimate of in-place gas for each subplay was then calculated. The gas in-place in each of the subplays in a play was summed to derive a mean estimate of total gas in-place for a play. Estimates were then made of the ranges for each play attribute at the 95th and 5th percentile levels. The attributes were treated as independent continuous random variables, and ranges of gas in-place for each subplay were then calculated using probability theory. The subplays were aggregated assuming perfect positive correlation to calculate the range of gas in-place for each play. Finally, all of the plays were aggregated assuming perfect positive correlation to assess the total in-place gas in all of the plays in the Wind River Basin.Estimates of mean gas in-place for the twenty two plays are: 1) Upper Cretaceous Frontier Formation highly overpressured-118. trillion cubic feet (tcf);...

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Using a geology-based assessment methodology, the U.S. Geological Survey assessed undiscovered, technically recoverable continuous mean resources of 46.3 billion barrels of oil and 281 trillion cubic feet of gas in the Wolfcamp shale and Bone Spring Formation of the Delaware Basin in the Permian Basin Province, southeast New Mexico and west Texas.