Prenatal cocaine exposure alters alpha2 receptor expression in adolescent rats

Background  

Prenatal cocaine exposure produces attentional deficits which to persist through early childhood. Given the role of norepinephrine (NE) in attentional processes, we examined the forebrain NE systems from prenatal cocaine exposed rats. Cocaine was administered during pregnancy via the clinically relevant intravenous route of administration. Specifically, we measured α₂-adrenergic receptor (α₂-AR) density in adolescent (35-days-old) rats, using [³H]RX821002 (5 nM).     

A short enantioselective synthesis of N-Boc-(2R,3R)-3-methyl-3-hydroxypipecolic acid from geraniol

The asymmetric synthesis of (2R,3R)-3-methyl-3-hydroxypipecolic acid, a key intermediate in the synthesis of dual MMP-13/aggrecanase inhibitors, is described. The title compound is prepared in seven steps with an overall yield of 41% starting from geraniol. Key steps in the synthesis include Sharpless asymmetric epoxidation, which establishes the chiral centers, and a one-pot oxidative olefin cleavage/reductive amination sequence that closes the piperidine ring.     

OPC Lattices and Congruence Heredity

We prove that if is a finite algebra which satisfies a nontrivial idempotent Mal’cev condition, and if Con contains a copy of an order polynomially complete lattice other than , , or Con, then Con is not hereditary. Received March 7, 2006; accepted in final form December 5, 2006.     

Determination of antioxidants in polyolefins using total dissolution methodology followed by RPLC

Antioxidants are added to polyolefins to improve the stability of the resin from oxidation and degradation during processing of the finished article and to increase product lifetime. Without antioxidants, polyolefins would quickly degrade during and after the extrusion or thermoforming process, which would cause inferior appearance and physical properties. The proper level must be added to protect the polymer and to minimize cost. Antioxidants are usually extracted from the resin and the extract is analyzed by RPLC, GC, or Fourier transform infrared spectroscopy. Unfortunately, many of these procedures require significant manual labor, time, and solvent, rendering them impractical for high-throughput work processes. In addition, they may not provide complete extraction of the additives depending upon the type of resin. A validated analytical method was needed for the determination of three common antioxidants, Irganox(?) 1010, Irganox(?) 1076, and Irgafos(?) 168 in polyolefin resins. This paper shows the determination of these antioxidants using dissolution followed by precipitation with o-xylene and methanol. Direct analysis of the solution is achieved in 8?min using RPLC.     

Size-dependence of the heat capacity and thermodynamic properties of hematite (α-Fe2O3)

The heat capacity of a 13 nm hematite (α-Fe₂O₃) sample was measured from T = (1.5 to 350) K using a combination of semi-adiabatic and adiabatic calorimetry. The heat capacity was higher than that of the bulk which can be attributed to the presence of water on the surface of the nanoparticles. No anomaly was observed in the heat capacity due to the Morin transition and theoretical fits of the heat capacity below T = 15 K show a small T³ dependence (due to lattice contributions) with no T^3/2 dependence. This suggests that there are no magnetic spin-wave contributions to the heat capacity of 13 nm hematite. The use of a large linear term to fit the heat capacity below T = 15 K is most likely due to superparamagnetic contributions. A small anomaly within the temperature range (4 to 8) K was attributed to the presence of uncompensated surface spins.     

"Tying up loose ends" – silicone surfactants as stabilizing agents for flexible polyurethane foam

This paper is a tribute to the work of Dr. Michael J. Owen and colleagues in revealing the mechanism of the silicone surfactant-driven stabilization of flexible polyurethane foam. This work, performed at Midland Silicones (acquired by Dow Corning Corporation in 1967), was the inspiration for a body of experimental and theoretical research performed by the present authors in the mid-1990's. For flexible polyurethane foam, the surfactant is necessary to stabilize the liquid foamy mass before it hardens into an elastomeric sponge. Owen and coworkers demonstrated that in order to stabilize the foam the surfactant must (1) significantly lower the equilibrium surface tension of the liquid, (2) exhibit a dynamic surface tension within a narrow range of values, and (3) have an appreciable but low surface viscosity. The recent work of the authors has both validated these observations and extended their scope. They have modeled the stabilization process and have found that stability is the result of a delicate interplay of surface viscosity and elasticity which are functions of both structure and excess surface concentration of the surfactant. This modeling work was validated experimentally by investigating the drainage of model polyurethane thin liquid films ("soap films") containing silicone surfactants. The seminal nature of the work done by Owen and coworkers was reinforced by the authors' discovery that many of the original conclusions were validated by the recent work.     

Line shapes (absorption coefficients) for satellites and inversion of the data to obtain interaction potentials

Line shapes for cesium broadened by xenon and neopentane have been measured in an absorption cell. The growth of the red satellites. both primary and secondary, were studied on the first five principal series doublets and on the first S - D forbidden doublet. An inversion scheme based on a nearest-neighbor density was employed to invert the measured line shapes and obtain difference potential estimates. It is apparent from the inversion scheme that minor inflections in the difference potential map into strong features in the frequency plane and that contrary to popular assumption, absolute extrema may not be necessary for satellite interpretation. Strength effects observed on the forbidden satellites also demonstrate that the radial dependence of the dipole moment must be accounted for in certain cases.     

Laser excited fluorescence in the cesium-xenon excimer and the cesium dimer

Argon ion laser lines are used to excite fluorescence in a mixture of cesium and xenon. Excimer band fluorescence is observed at higher pressures (about 1 atm) while at lower pressures (several torr) a diffuse fluorescence due to the cesium dimer is observed whose character changes with exciting wavelength. The excimer fluorescence is shown to be directly related to the location of the exciting wavelength within previously measured Cs/Xe line shapes. This fact suggests that the excimer systems may be efficiently pumped through these line shapes. Qualitative energy-level schemes are proposed to explain the observations in both the excimer and dimer systems.