The reactions of general practitioners, nurses and midwives in Flanders concerning breast cancer risks in a high-risk situation

OBJECTIVE: To investigate the reactions of general practitioners (GPs), nurses and midwives concerning the cancer risks in a high-risk family. METHODS: Questionnaires were sent to 356 GPs, 881 nurses and 119 midwives. RESULTS: The response rate was 60% for GPs, 58% for midwives and 33% for nurses. The breast cancer risk of an unaffected patient from a high-risk family as well as the risk of her daughter were mostly (>80%) correctly evaluated as increased. The percentage answering 'increased risk' dropped to 40% for the daughters of the patient's brother. Half of the GPs and nurses/midwives explicitly mentioned that a predictive DNA test was available. Less than one third would recommend such a test for a young child. Reluctance was also observed regarding prophylactic mastectomy. CONCLUSION: These results should be taken into account in genetic education initiatives for GPs, nurses and midwives.     

Stochastic amperometric fluctuations as a probe for dynamic adsorption in nanofluidic electrochemical systems

Adsorption of analyte molecules is ubiquitous in nanofluidic channels due to their large surface-to-volume ratios. It is also difficult to quantify due to the nanometric scale of these channels. We propose a simple method to probe dynamic adsorption at electrodes that are embedded in nanofluidic channels or which enclose nanoscopic volumes. The amperometric method relies on measuring the amplitude of the fluctuations of the redox cycling current that arise when the channel is diffusively coupled to a bulk reservoir. We demonstrate the versatility of this new method by quantifying adsorption for several redox couples, investigating the dependence of adsorption on the electrode potential and studying the effect of functionalizing the electrodes with self-assembled monolayers of organothiol molecules bearing polar end groups. These self-assembled monolayer coatings are shown to significantly reduce the adsorption of the molecules on to the electrodes. The detection method is not limited to electrodes in nanochannels and can be easily extended to redox cycling systems that enclose very small volumes, in particular scanning electrochemical microscopy with nanoelectrodes. It thus opens the way for imaging spatial heterogeneity with respect to adsorption, as well as rational design of interfaces for redox cycling based sensors.     

Biological soft X‐ray tomography on beamline 2.1 at the Advanced Light Source

Beamline 2.1 (XM‐2) is a transmission soft X‐ray microscope in sector 2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. XM‐2 was designed, built and is now operated by the National Center for X‐ray Tomography as a National Institutes of Health Biomedical Technology Research Resource. XM‐2 is equipped with a cryogenic rotation stage to enable tomographic data collection from cryo‐preserved cells, including large mammalian cells. During data collection the specimen is illuminated with `water window' X‐rays (284–543 eV). Illuminating photons are attenuated an order of magnitude more strongly by biomolecules than by water. Consequently, differences in molecular composition generate quantitative contrast in images of the specimen. Soft X‐ray tomography is an information‐rich three‐dimensional imaging method that can be applied either as a standalone technique or as a component modality in correlative imaging studies.     

Microwave Spectrum, Structure, and Hyperfine Constants of Kr-AgCl: Formation of a Weak Kr-Ag Covalent Bond

The pure rotational spectrum of the complex Kr-AgCl has been measured between 8-15 GHz using a cavity pulsed-jet Fourier transform microwave spectrometer. The complex was found to be linear and relatively rigid, with a Kr-Ag bond length of approximately 2.641 ?. The Kr-Ag stretching frequency was estimated to be 117 cm(-1). Ab initio calculations performed at the MP2 level of theory gave the geometry, vibration frequencies, Kr-Ag bond dissociation energy, and orbital populations. The Kr-Ag bond dissociation energy was estimated to be approximately 28 kJ mol(-1). The Kr-Ag force constant and dissociation energy are greater than those of Ar-Ag in Ar-AgCl. The chlorine nuclear quadrupole coupling constants show slight changes on complex formation. Ab initio orbital population analysis shows a small shift in sigma-electron density from Kr to Ag on complex formation. The combined experimental and ab initio results are consistent with the presence of a weak Kr-Ag covalent bond. Copyright 2001 Academic Press.     

Matryoshka locally resonant sonic crystal

The results of numerical modeling of sonic crystals with resonant array elements are reported. The investigated resonant elements include plain slotted cylinders as well as their various combinations, in particular, Russian doll or Matryoshka configurations. The acoustic band structure and transmission characteristics of such systems have been computed with the use of finite element methods. The general concept of a locally resonant sonic crystal is proposed that utilizes acoustic resonances to form additional band gaps that are decoupled from Bragg gaps. An existence of a separate attenuation mechanism associated with the resonant elements that increases performance in the lower frequency regime has been identified. The results show a formation of broad band gaps positioned significantly below the first Bragg frequency. For low frequency broadband attenuation, a most optimal configuration is the Matryoshka sonic crystal, where each scattering unit is composed of multiple concentric slotted cylinders. This system forms numerous gaps in the lower frequency regime, below Bragg bands, while maintaining a reduced crystal size viable for noise barrier technology. The finding opens alternative perspectives for the construction of sound barriers in the low frequency range usually inaccessible by traditional means including conventional sonic crystals.