Macrocyclic Liquid Crystals Blake, Alexander J.; Bruce, Duncan W.; Fallis, Ian A. ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
02/1996, Volume:
354, Issue:
1706
Journal Article
Peer reviewed
The synthesis of macrocycle-containing liquid crystals is reviewed with particular emphasis on derivatives of synthetic aza crowns. The synthesis of the C-functionalized thioether crowns (HO)214aneS4 ...and (HO)216aneS4 is described, and their derivatization to give oligobenzoate esters discussed. The formation of mesogens and metallomesogens in these systems has been achieved, and structural studies have been utilized to probe ionophore and tail-group conformation(s). Structural studies of functionalized thioether crowns suggests a relationship between potential mesogen formation and the conformational flexibility of the incorporated crown thioether.
The role of perfusion pressure and flow during cardiopulmonary bypass with moderate hypothermia and hemodilution in the development of new postoperative renal or clinically apparent cerebral ...dysfunction was examined in 504 adults. Cardiopulmonary bypass flow was targeted at greater than 40 mL.kg-1.min-1 and pressure at greater than 50 mm Hg. Flows and pressures less than target occurred in 21.6% and 97.1% of patients, respectively. Fifteen patients (3.0%) suffered new renal and 13 (2.6%) new central nervous system dysfunction. Low pressure or flow during cardiopulmonary bypass, expressed in absolute values or in intensity-duration units, were not predictors of either adverse outcome. Multivariate analysis identified use of postoperative intraaortic balloon counterpulsation (p less than 10(-6, excessive blood loss in the ICU (p less than 10(-4, need for vasopressors before cardiopulmonary bypass (p less than 10(-4, postoperative myocardial infarction (p less than 10(-3, emergency reoperation (p less than 0.002), excessive postoperative transfusion (p less than 0.02), and chronic renal disease (p less than 0.03) as independent predictors of postoperative renal dysfunction. Independent predictors of postoperative central nervous system dysfunction were cardiopulmonary resuscitation in the intensive care unit (p less than 10(-6, intracardiac thrombus or valve calcification (p less than 0.02), and chronic renal disease (p less than 0.03). Age greater than 65 years (40.7% of patients) did not predict either outcome. We conclude that failure of the native circulation during periods other than cardiopulmonary bypass rather than the flows and pressures considered here is the major cause of renal and clinically apparent central nervous system dysfunction after cardiac operations.
Objective
To determine whether social network experience and perceptions of benefit of arthritis treatments influence the decision to seek diagnosis and treatment.
Methods
A population‐based ...telephone survey of 515 black and 455 white Medicare beneficiaries was conducted. Validated questionnaires adapted for use in a telephone interview were used to identify people with self‐reported symptoms of hip or knee pain. Treatment history for arthritis‐related pain and perceptions of benefit of treatment were also assessed.
Results
Forty‐two percent of blacks and 31% of whites reported hip or knee pain. Forty‐two percent of blacks and 65% of whites reported knowing someone who had surgery for hip or knee pain (P < 0.0001). Blacks were less likely than whites to report that surgery had helped someone they knew with hip or knee pain (not significant).
Conclusion
Blacks know fewer people who have had surgical treatment of hip and knee pain than whites and appear to be less likely to perceive that such treatment is beneficial.
The SNO+ Collaboration reports the first evidence of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240~km away in Ontario, Canada. This analysis uses events ...with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods are used to distinguish reactor antineutrinos from background events in 190 days of data and yield consistent evidence for antineutrinos with a combined significance of 3.5\(\sigma\).
Air fluorescence detectors traditionally determine the dominant chemical composition of the ultrahigh energy cosmic ray flux by comparing the averaged slant depth of the shower maximum,
X
max, as a ...function of energy to the slant depths expected for various hypothesized primaries. In this paper, we present a method to make a direct measurement of the expected mean number of protons and iron by comparing the shapes of the expected
X
max distributions to the distribution for data. The advantages of this method includes the use of information of the full distribution and its ability to calculate a flux for various cosmic ray compositions. The same method can be expanded to marginalize uncertainties due to choice of spectra, hadronic models and atmospheric parameters. We demonstrate the technique with independent simulated data samples from a parent sample of protons and iron. We accurately predict the number of protons and iron in the parent sample and show that the uncertainties are meaningful.
Oligodeoxyribonucleoside methylphosphonates contain nonionic 3'-5' linked methylphosphonate internucleotide bonds in place of the normal charged phosphodiester linkage of natural nucleic acids. These ...oligomers are resistant to nuclease hydrolysis, can pass through the membranes of mammalian cells in culture and can form stable hydrogen-bonded complexes with complementary nucleotide sequences of cellular RNAs such as mRNA. The oligomers are readily synthesized on insoluble polymer supports. Their chainlength and nucleotide sequence can be determined by chemical sequencing procedures. Oligonucleoside methylphosphonates which are complementary to the 5'-end, initiation codon region, or coding region of rabbit globin mRNA inhibit translation of the mRNA in rabbit reticulocyte lysates and globin synthesis in rabbit reticulocytes. This inhibition is due to the interaction of the oligomers with mRNA and the extent of inhibition is influenced by the secondary structure of the mRNA and the location of oligomer binding site on the mRNA. Oligomers complementary to the initiation codon regions of N, NS and G protein mRNAs of Vesicular stomatitis virus (VSV) inhibit virus protein synthesis in VSV-infected Mouse L-cells. These oligomers do not affect L-cell protein synthesis or growth. Virus protein synthesis and growth can also be selectively inhibited by oligonucleoside methylphosphonates which are complementary to the donor or acceptor splice junctions of virus pre mRNA. An oligomer complementary to the donor splice junction of SV40 large T antigen mRNA inhibits T-antigen synthesis in SV40-infected African green monkey kidney cells but does not inhibit overall cellular protein synthesis.
Combining different observational probes, such as galaxy clustering and weak lensing, is a promising technique for unveiling the physics of the Universe with upcoming dark energy experiments. The ...galaxy redshift sample from the Dark Energy Spectroscopic Instrument (DESI) will have a significant overlap with major ongoing imaging surveys specifically designed for weak lensing measurements: the Kilo-Degree Survey (KiDS), the Dark Energy Survey (DES) and the Hyper Suprime-Cam (HSC) survey. In this work we analyse simulated redshift and lensing catalogues to establish a new strategy for combining high-quality cosmological imaging and spectroscopic data, in view of the first-year data assembly analysis of DESI. In a test case fitting for a reduced parameter set, we employ an optimal data compression scheme able to identify those aspects of the data that are most sensitive to the cosmological information, and amplify them with respect to other aspects of the data. We find this optimal compression approach is able to preserve all the information related to the growth of structure; we also extend this scheme to derive weights to be applied to individual galaxies, and show that these produce near-optimal results.
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