Clarification of plasma from whole human blood using ultrasound

There has been interest for a number of years in the possibility of separating blood into cells and plasma by methods other than centrifugation, so that the plasma can be analysed on-line. Cells in whole blood normally occupy about 45% of the suspension volume. It has been shown with a number of different cell types, such as yeast and bacteria, that for concentrations of this order the cells are not as efficiently harvested by ultrasound as those for lower concentrations. In this study, removal of cells from 3-4 ml whole blood volumes has been examined in ultrasonic standing wave fields from tubular transducers driven at a frequency of 1.6 MHz. Samples of whole human blood (n = 11) from two volunteers have been processed by three tubular transducers where high levels of cell removal, 99.7% on average, have been demonstrated with high reproducibility between samples as well as for different transducers.     

Reduction of anxiety during MR imaging: a controlled trial

An anxiety reduction protocol was developed and evaluated for routine use with neurology and neuropsychiatry patients undergoing brain or spinal scans. Thirty five patients underwent standard procedures, with limited information given in advance. Twenty nine experimental patients received a booklet giving information about the scanning procedure and advice on cognitive strategies for anxiety reduction, a tape-recorded demonstration of scanner noise, a visit to the control room before entering the scanner, a device to signal for adjustment of music volume, precise timings of each scan, and a clock visible during scanning. Anxiety was measured before, during, and after scanning, using subjective ratings and a retrospective version of the Spielberger State Anxiety Scale. There was no difference in anxiety between groups immediately prior to the scan and immediately after entering the scanner. Patients in the experimental group were significantly less anxious during the scan than control patients, as measured by mean anxiety ratings made during the imaging procedure and by retrospective State Anxiety scores completed immediately after leaving the scanner. The results show that scan-related anxiety can be reduced by introducing these simple changes to MR imaging procedures, with minimal cost, no special training of staff, and no disruption of the running of the MR Unit.     

Green chemical functionalization of single-walled carbon nanotubes in ionic liquids

Single walled carbon nanotubes (SWNTs) are exfoliated and functionalized predominantly as individuals by grinding them for minutes at room temperature with aryldiazonium salts in the presence of ionic liquids (ILs) and K(2)CO(3). This constitutes an extremely rapid and mild green chemical functionalization process for obtaining the individualized nanotube structures. A number of ILs and various reaction conditions were surveyed. Raman, XPS, UV/vis/NIR spectroscopies, thermogravimetric analysis, and atomic force and transmission electron microscopies were used to characterize the products.     

Isotactic sequence lengths by ozonation of poly(propylene oxide)

Ozonation followed by lithium aluminum hydride reduction cleaved high molecular weight isotactic poly(propylene oxide) to crystalline polyglycols. From the melting point and molecular weight of the latter, the molar freezing point depression produced by end groups is found to be ca. 18°C./mole, as compared to that estimated for poly(ethylene glycols), K_f = 12°C./mole, from earlier data. By assuming syndiotactic placements (or other irregularities) would produce the same molar depression, the melting point of isotactic poly(propylene oxides) produced by various catalysts has been used to estimate the isotactic sequence lengths.     

Structure‐Property Optimizations in Donor Polymers via Electronics,Substituents, and Side Chains Toward High Efficiency Solar Cells

Many advances in organic photovoltaic efficiency are not yet fully understood and new insight into structure‐property relationships is required to push this technology into broad commercial use. The aim of this article is not to comprehensively review recent work, but to provide commentary on recent successes and forecast where researchers should look to enhance the efficiency of photovoltaics. By lowering the LUMO level, utilizing electron‐withdrawing substituents advantageously, and employing appropriate side chains on donor polymers, researchers can elucidate further aspects of polymer‐PCBM interactions while ultimately developing materials that will push past 10% efficiency.     

Validity of the rotational sudden approximation for vibrational relaxation in He + CO

Calculations of cross sections and rate constants are reported for the vibrational relaxation of CO in collision with ³He and ⁴He. Results computed using a semiclassical technique and a vibrational close-coupling, rotational infinite-order sudden method are compared.     

Conformational studies of 1,2,3-trichloro- and 1,2,3-tribromopropane by nuclear magnetic resonance spectroscopy: attractive parallel (1:3) halogen-hydr

Analysis of the NMR spectra of 1,2,3-trichloropropane and 1,2,3-tribromopropane in various media shows the most stable conformer to be AG_-. The populations of several conformera have been estimated by using pure trans and gauche coupling constants obtained from closely similar molecules. The calculated populations found in non-polar solvents agree well with those obtained by electron diffraction studies in the gas phase. It is suggested that the AG_- form is stabilised relative to AG₊ by the former having two parallel (1:3) halogen-hydrogen attractions against one in the AG₊ form. Comparison is made to related molecules where the most stable conformers also have the greatest number of parallel (1:3) halogen-hydrogen interactions.