10 research outputs found
Biomolecular electronic devices based on self-organized deoxyguanosine nanocrystals.
We report on a new class of hybrid electronic devices based on a DNA nucleoside (deoxyguanosine lipophilic derivative) whose assembled polymeric ribbons interconnect a submicron metallic gate. The device exhibits large conductivity at room temperature, rectifying behavior and strong current-voltage hysteresis. The transport mechanism through the molecules is investigated by comparing films with different self-assembling morphology. We found that the main transport mechanism is connected to pi-pi interactions between guanosine molecules and to the formation of a strong dipole along ribbons, consistently with the results of our first-principles calculations
BeppoSAX Observations of 1 Jy BL Lacertae Objects. I
We present new BeppoSAX observations of seven BL Lacertae objects selected
from the 1 Jy sample plus one additional source. The collected data cover the
energy range 0.1 - 10 keV (observer's frame), reaching ~ 50 keV for one source
(BL Lac). All sources characterized by a peak in their multifrequency spectra
at infrared/optical energies (i.e., of the LBL type) display a relatively flat
(alpha_x ~ 0.9) X-ray spectrum, which we interpret as inverse Compton emission.
Four objects (2/3 of the LBL) show some evidence for a low-energy steepening
which is likely due to the synchrotron tail merging into the inverse Compton
component around ~ 1 - 3 keV. If this were generally the case with LBL, it
would explain why the 0.1 - 2.4 keV ROSAT spectra of our sources are
systematically steeper than the BeppoSAX ones (by ~ 0.5 in alpha_x). The
broad-band spectral energy distributions fully confirm this picture and a
synchrotron inverse Compton model allows us to derive the physical parameters
(intrinsic power, magnetic field, etc.) of our sources. Combining our results
with those obtained by BeppoSAX on BL Lacs covering a wide range of synchrotron
peak frequencies, we confirm and clarify the dependence of the X-ray spectral
index on synchrotron peak frequency originally found in ROSAT data.Comment: 14 pages, 7 figures. Accepted for publication in MNRAS. Postscript
file also available at
http://icarus.stsci.edu/~padovani/xrayspectra_papers.htm
Lunar Gravitational-Wave Antenna
Monitoring of vibrational eigenmodes of an elastic body excited by
gravitational waves was one of the first concepts proposed for the detection of
gravitational waves. At laboratory scale, these experiments became known as
resonant-bar detectors first developed by Joseph Weber in the 1960s. Due to the
dimensions of these bars, the targeted signal frequencies were in the kHz
range. Weber also pointed out that monitoring of vibrations of Earth or Moon
could reveal gravitational waves in the mHz band. His Lunar Surface Gravimeter
experiment deployed on the Moon by the Apollo 17 crew had a technical failure
rendering the data useless. In this article, we revisit the idea and propose a
Lunar Gravitational-Wave Antenna (LGWA). We find that LGWA could become an
important partner observatory for joint observations with the space-borne,
laser-interferometric detector LISA, and at the same time contribute an
independent science case due to LGWA's unique features. Technical challenges
need to be overcome for the deployment of the experiment, and development of
inertial vibration sensor technology lays out a future path for this exciting
detector concept.Comment: 29 pages, 17 figure
Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)
This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands
Performance measures for endoscopic retrograde cholangiopancreatography and endoscopic ultrasound: A European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative
The European Society of Gastrointestinal Endoscopy (ESGE) and United European Gastroenterology present a short list of key performance measures for endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP). We recommend that endoscopy services across Europe adopt the following seven key and one minor performance measures for EUS and ERCP, for measurement and evaluation in daily practice at centre and endoscopist level: 1 Adequate antibiotic prophylaxis before ERCP (key performance measure, at least 90%); 2 antibiotic prophylaxis before EUS-guided puncture of cystic lesions (key performance measure, at least 95%); 3 bile duct cannulation rate (key performance measure, at least 90%); 4 tissue sampling during EUS (key performance measure, at least 85%); 5 appropriate stent placement in patients with biliary obstruction below the hilum (key performance measure, at least 95%); 6 bile duct stone extraction (key performance measure, at least 90%); 7 post-ERCP pancreatitis (key performance measure, less than 10%); and 8 adequate documentation of EUS landmarks (minor performance measure, at least 90%). This present list of quality performance measures for ERCP and EUS recommended by the ESGE should not be considered to be exhaustive; it might be extended in future to address further clinical and scientific issues.status: publishe
A predictive model identifies patients most likely to have inadequate bowel preparation for colonoscopy
An inadequate level of bowel preparation can affect the efficacy and safety of colonoscopy. Although some factors have been associated with outcome, there is no strategy to identify patients at high risk for inadequate preparation. We searched for factors associated with an inadequate level of preparation and tested the validity of a predictive clinical rule based on these factors
Performance measures for ERCP and endoscopic ultrasound: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative
The European Society of Gastrointestinal Endoscopy and United European Gastroenterology present a short list of key performance measures for endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP). We recommend that endoscopy services across Europe adopt the following seven key and one minor performance measures for EUS and ERCP, for measurement and evaluation in daily practice at center and endoscopist level: 1: Adequate antibiotic prophylaxis before ERCP (key performance measure, at least 90\u200a%); 2: Antibiotic prophylaxis before EUS-guided puncture of cystic lesions (key performance measure, at least 95\u200a%); 3: Bile duct cannulation rate (key performance measure, at least 90\u200a%); 4: Tissue sampling during EUS (key performance measure, at least 85\u200a%); 5: Appropriate stent placement in patients with biliary obstruction below the hilum (key performance measure, at least 95\u200a%); 6: Bile duct stone extraction (key performance measure, at least 90\u200a%); 7: Post-ERCP pancreatitis (key performance measure, less than 10\u200a%). 8: Adequate documentation of EUS landmarks (minor performance measure, at least 90\u200a%).This present list of quality performance measures for ERCP and EUS recommended by ESGE should not be considered to be exhaustive: it might be extended in future to address further clinical and scientific issues
Endoscopy units and the COVID-19 Outbreak: A Multi-Center Experience from Italy
experience of endoscopic unit during covid outbrea