Ion-Pairing Liquid Chromatography Coupled with Mass Spectrometry for the Simultaneous Determination of Nucleosides and Nucleotides

Adenosine and its corresponding nucleotides adenosine 5'-monophosphate (AMP), adenosine 5'-diphosphate ( ADP ) and adenosine 5'-triphos-phate (ATP) are important biomolecules that provide energy and substrates for various cellular bio-chemical processes. There have been strong     

How do women decide? Accepting or declining BRCA1/2 testing in a nationwide clinical sample in the United States

OBJECTIVE: To examine the role of the practitioner, informed consent, and genetic counseling in genetic testing decisions and to assess their relative influence on women's decision to have clinical BRCA1/2 testing. METHODS: Qualitative study using in-depth open-ended interviews with 68 women who had considered clinical BRCA1/2 testing. RESULTS: Slightly less than half of the women who had considered BRCA1/2 testing were found to have had a clear and preexisting desire to test or not to test, irrespective of practitioner attitude or advice. CONCLUSION: The decision to accept or decline genetic testing is the result of a complex process that goes beyond interactions between health care providers and patients, indicating a caution against exclusive reliance on informed consent or counseling encounters.     

Resonant Raman scattering characterization of carbon nanotubes grown with different catalysts

Single-walled carbon nanotube samples produced in the presence of different combinations of metal catalysts have been studied by resonant Raman spectroscopy. The diameter distribution of different samples has been determined by analysis of the laser excitation energy dependence of the tangential modes associated with metallic nanotubes. These modes are resonantly enhanced over a narrow range of the exciting energies, which shifts for different samples. The Raman cross-section expression has been used to fit the experimental Raman excitation profiles. This procedure was used to determine the mean value and the width of the distribution of diameters within each sample.     

The preparation of carbon aerogels based upon the gelation of resorcinol-furfural in isopropanol with organic base catalyst

Carbon aerogels with high BET surface area were developed by sol-gel polycondensation of resorcinol and furfural in isopropanol using hexamethylenetetramine (HMTA) as a catalyst, and then directly drying the organic gels under isopropanol supercritical conditions, followed by carbonization under a nitrogen atmosphere. The preparation conditions of carbon aerogels were explored by changing the mole ratio of resorcinol to basic catalyst HMTA (R/C), the ratio of resorcinol to isopropanol (R/I), and the mole ratio of resorcinol to furfural (R/F). The effect of these preparation conditions on the porous structure of the carbon aerogels obtained was studied by nitrogen adsorption isotherms. According to the characterizations of TEM, SEM and nitrogen adsorption, the carbon aerogels obtained have a three-dimensional network that consists of carbon nano-particles with size from 20 to 30 nm, which define numerous micropores, mesopores and macropores. HMTA reacts not only as a catalyst but also as a reagent in the gelation polymerization. XRD characterization indicates that carbon aerogels have disordered nanocrystalline structures similar to activated carbon.     

Structure and electrochemical properties of carbon aerogels polymerized in the presence of Cu

Copper-loaded organic aerogels were prepared by sol–gel polymerization of resorcinol and formaldehyde in a solution of Cu(NO₃)₂. Carbon aerogels derived from the heat-treatment of the organic precursor kept their particulate structure, according to TEM observations. The particle size in Cu-loaded carbon aerogel samples becomes larger with a higher concentration of Cu incorporated into their texture, due to the presence of Cu²⁺ rather than the pH conditions in the sol–gel process. The nitrogen adsorption measurement of Cu-loaded samples showed their characteristic pore structure, i.e., a combination of microporosity and mesoporosity both developed in their texture. Especially, their advanced microporosity, which was still found after carbonization at 1273 K, was very unique, considering that micropores in organic aerogels often decreased in size during heat-treatment around this temperature range. This microporosity could be related to their stacking structure of aromatic layers revealed by STAC–XRD analysis, indicating a looser packing of aromatic layers in their structure. Application of Cu-loaded samples to electric double-layer capacitor is also discussed from the viewpoint of the amount of Cu as well as the pore structure of the samples.