Analysis of the effect of malaria on lipid composition of rhesus plasma

The phospholipid distribution and the ratio of cholesterol-to-cholesterol ester have been determined for plasmas isolated from normal, fasted and P. knowlesi-infected rhesus monkeys. Compared to normal plasmas, the infected plasmas show phospholipid patterns with slight increases in phosphatidylcholine and larger decreases in lysophosphatidylcholine. The cholesterol-to-cholesterol ester ratio is always less than one in normal plasmas and greater than one for infected plasmas. There are no differences between samples isolated from fasting and non-fasting animals for any of the constituents examined.     

Part II. Chromatography using ultra-stable metal oxide-based stationary phases for HPLC

In this part of the review authors discuss methods used for modification of metal oxide surfaces. On the basis of literature data it is shown, that silanization of the surfaces do not form stable supports for chromatography. On the other hand, the success of polymer modified surfaces such as polybutadiene (PBD) and polystyrene (PS) is emphasized. Permanent modification of metal oxide surfaces with Lewis bases is also widely discussed. Chromatographic properties of polymer modified surfaces of zirconia are discussed in details. The perspectives of carbon-coated metal oxide surfaces in HPLC and high temperature separations are described.     

Crystallization of silver stearate from sodium stearate dispersions

Silver carboxylates, the common silver source used for photothermographic imaging materials, are normally obtained from the reaction between sodium soap (e.g., sodium stearate) and silver nitrate. They form platelet-like crystals with a lamellar structure in water at room temperature. Light microscopy investigations reveal that the formation of silver stearate (AgSt) crystals follows a diffusion-controlled mechanism. The reaction between the sodium soap and silver nitrate preferentially occurs in solution rather than on the soap fiber solid interface. Cryogenic transmission electron microscopy, together with an on-the-grid reaction technique, provides a useful tool to directly image silver stearate microstructures at the initial stages of AgSt precipitation. The AgSt reaction product first forms particles about 5 nm in size, which is similar to the d-spacing of final AgSt crystals. Those particles aggregate to produce larger and loosely packed embryonic crystals, the precursors to the ultimate silver stearate crystals.     

Characterization and synthesis of a new calcium antagonist from the venom of a fishing spider

A new calcium antagonist, CNS 2103, is isolated from the venom of a fishing spider, Dolomedes okefinokensis. The structure of this compound is derived from spectroscopic data, including tandem mass spectrometry. A flexible, convergent synthesis of CNS 2103 is described.     

Experimental characterization of a two-photon memory

We demonstrate the recording of 100 planes of digital images in a page-oriented two-photon memory and characterize the images in terms of signal-to-noise ratio and bit error rate. Possible error sources in the recording are discussed, and methods for compensating for some of these effects are presented. Looking at the distributions of the normalized bit intensities, we are able to estimate the minimum achievable bit error rate for this system.     

Water-soluble copolymers. XIII. Copolymers of acrylamide with sodium-3-acrylamido-3-methylbutanoate: Solution properties

Dilute solution properties of copolymers of acrylamide (AM) with sodium-3-acrylamido-3-methylbutanoate (NaAMB) of known molecular weight have been studied as a function of composition, temperature, time, pH, and added electrolytes. Phase separation and potentiometric studies have also been performed. The AM–NaAMB copolymers exhibit high solution viscosities, good salt tolerance, and moderate viscosity-temperature coefficients. In addition, these copolymers exhibit no phase separation in the presence of divalent cations as is common with many such carboxylated polyelectrolytes. These properties are due to favorable conformations in solution resulting from microstructure and hydrogen bonding effects.     

Exploratory organometal-sulfur chemistry; syntheses and unusual properties of rhenium CH2SR,CHSRR′, and CHSR]+ complexes

The methylidene complex [(η-C₅H₅)Re(NO)(PPh₃)(CH₂)]⁺PF₆^?(I) yields kinetically labile sulfonium salts when treated with CH₃SCH₃, CH₃SCH₂C₆H₅, and (η-C₅H₅)Re(NO)(PPh₃)(CH₂SCH₃) (V);the binuclear adduct formed in the latter case, [(η-C₅H₅)Re(NO)(PPh₃)CH₂]₂S⁺CH₃ (VI), is substantially more stable than the others and undergoes hydride transfer disproportionation to [(η-C₅H₅)Re(NO)(PPh₃)(CHSCH₃)]⁺PF₆^?(VII) and (η-C₅H₅)Re(NO)(PPh₃)(CH₃) (VIII) when heated.     

An iterative procedure for the solution of constrained nonlinear equations with application to optimization problems

LetH ₁ andH ₂ denote Hilbert spaces and suppose thatD is a subset ofH ₁. This paper establishes the local and linear convergence of a general iterative technique for finding the zeros ofG:DH ₂ subject to the general constraintP(x)=x, whereP:DD. The results are then applied to several classes of problems, including those of least squares, generalized eigenvalues, and constrained optimization. Numerical results are obtained as the procedure is applied to finding the zeros of polynomials in several variables.This work was supported by NSF grant G J 34737.