146 research outputs found
Does adjunctive oxytocin infusion during balloon cervical ripening improve labor induction?
Q: Does adjunctive oxytocin infusion during balloon cervical ripening improve labor induction? Evidence-based answer: YES. Compared to the use of a transcervical balloon alone, combined cervical ripening with a balloon catheter and oxytocin shortens the time to overall delivery by 3 hours and the time to vaginal delivery by 4 hours, without altering the rate of cesarean section (strength of recommendation [SOR]: A, network meta-analysis). The effect is more pronounced in nulliparous patients (SOR: A, meta-analysis). When combined therapy is used, 6 hours of balloon time may result in faster delivery than 12 hours (SOR: B, single randomized controlled trial [RCT]). Fixed-dose oxytocin and titrated oxytocin appear to have similar effect when combined with a cervical ripening balloon (SOR: C, underpowered RCT).Rachel Dubay, MD; Nicola Rentschler, MD; Dara Jolly, MD; Jon O. Neher, MD (Valley Family Medicine, Renton, WA) Sarah Safranek, MLIS (Librarian Emeritus, University of Washington, Seattle)Includes bibliographical reference
A simple model for the vibrational modes in honeycomb lattices
The classical lattice dynamics of honeycomb lattices is studied in the
harmonic approximation. Interactions between nearest neighbors are represented
by springs connecting them. A short and necessary introduction of the lattice
structure is presented. The dynamical matrix of the vibrational modes is then
derived, and its eigenvalue problem is solved analytically. The solution may
provide deeper insight into the nature of the vibrational modes. Numerical
results for the vibrational frequencies are presented. To show that how
effective our method used for the case of honeycomb lattice is, we also apply
it to triangular and square lattice structures. A few suggested problems are
listed in the concluding section.Comment: 9 pages, 12 figures, submitted to American Journal of Physic
Electron-Phonon Scattering in Metallic Single-Walled Carbon Nanotubes
Electron scattering rates in metallic single-walled carbon nanotubes are
studied using an atomic force microscope as an electrical probe. From the
scaling of the resistance of the same nanotube with length in the low and high
bias regimes, the mean free paths for both regimes are inferred. The observed
scattering rates are consistent with calculations for acoustic phonon
scattering at low biases and zone boundary/optical phonon scattering at high
biases.Comment: 4 pages, 5 figure
Theory of superconductivity of carbon nanotubes and graphene
We present a new mechanism of carbon nanotube superconductivity that
originates from edge states which are specific to graphene. Using on-site and
boundary deformation potentials which do not cause bulk superconductivity, we
obtain an appreciable transition temperature for the edge state. As a
consequence, a metallic zigzag carbon nanotube having open boundaries can be
regarded as a natural superconductor/normal metal/superconductor junction
system, in which superconducting states are developed locally at both ends of
the nanotube and a normal metal exists in the middle. In this case, a signal of
the edge state superconductivity appears as the Josephson current which is
sensitive to the length of a nanotube and the position of the Fermi energy.
Such a dependence distinguishs edge state superconductivity from bulk
superconductivity.Comment: 5 pages, 2 figure
Phonon and plasmon excitation in inelastic electron tunneling spectroscopy of graphite
The inelastic electron tunneling spectrum (IETS)of highly oriented pyrolitic
graphite (HOPG) has been measured with scanning tunneling spectroscopy (STS) at
6K. The observed spectral features are in very good agreement with the
vibrational density of states (vDOS) of graphite calculated from first
principles. We discuss the enhancement of certain phonon modes by
phonon-assisted tunneling in STS based on the restrictions imposed by the
electronic structure of graphite. We also demonstrate for the first time the
local excitation of surface-plasmons in IETS which are detected at an energy of
40 meV.Comment: PRB rapid communication, submitte
Studying the local character of Raman features of single-walled carbon nanotubes along a bundle using TERS
Here, we show that the Raman intensity of the G-mode in tip-enhanced Raman spectroscopy (TERS) is strongly dependent on the height of the bundle. Moreover, using TERS we are able to position different single-walled carbon nanotubes along a bundle, by correlating the observed radial breathing mode (RBM) with the AFM topography at the measuring point. The frequency of the G- mode behaves differently in TERS as compared to far-field Raman. Using the RBM frequency, the diameters of the tubes were calculated and a very good agreement with the G--mode frequency was observed
Prediction of peptide and protein propensity for amyloid formation
Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔGº values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation
Use of the emergency department for less-urgent care among type 2 diabetics under a disease management program
Stented ureterovesical anastomosis in renal transplantation: does it influence the rate of urinary tract infections?
<p>Abstract</p> <p>Objective</p> <p>Our objective was to evaluate the impact of routine use of double-J stents on the incidence of urinary tract infection after renal transplantation.</p> <p>Methods</p> <p>We conducted a retrospective-comparative single-centre study in 310 consecutive adult deceased donor kidney recipients transplanted from 2002 to 2006. Patients were divided in two groups, with or without urinary stent implantation. To evaluate the predictive factors for UTI, donor and recipients pre- and post-transplantation data were analysed. Early urological complications and renal function within 12 months of transplantation were included as well.</p> <p>Results</p> <p>A total of 157 patients were enrolled to a stent (ST) and 153 patients to a no-stent (NST) group. The rate of urinary tract infection at three months was similar between the two groups (43.3% ST vs. 40.1% NST, p = 0.65). Of the identified pathogens Enterococcus and Escherichia coli were the most common species. In multivariate analysis neither age nor immunosuppressive agents, BMI or diabetes seemed to have influence on the rate of UTI. When compared to males, females had a significantly higher risk for UTI (54.0% vs. 33.5%).</p> <p>Conclusion</p> <p>Prophylactic stenting of the ureterovesical anastomosis does not increase the risk of urinary tract infection in the early postoperative period.</p
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