Sequential drain amylase to guide drain removal following pancreatectomy

BACKGROUND: Although used as criterion for early drain removal, postoperative day (POD) 1 drain fluid amylase (DFA) ≤ 5000 U/L has low negative predictive value for clinically relevant postoperative pancreatic fistula (CR-POPF). It was hypothesized that POD3 DFA ≤ 350 could provide further information to guide early drain removal. METHODS: Data from a pancreas surgery consortium database for pancreatoduodenectomy and distal pancreatectomy patients were analyzed retrospectively. Those patients without drains or POD 1 and 3 DFA data were excluded. Patients with POD1 DFA ≤ 5000 were divided into groups based on POD3 DFA: Group A (≤350) and Group B (>350). Operative characteristics and 60-day outcomes were compared using chi-square test. RESULTS: Among 687 patients in the database, all data were available for 380. Fifty-five (14.5%) had a POD1 DFA > 5000. Among 325 with POD1 DFA ≤ 5000, 254 (78.2%) were in Group A and 71 (21.8%) in Group B. Complications (35 (49.3%) vs 87 (34.4%); p = 0.021) and CR-POPF (13 (18.3%) vs 10 (3.9%); p < 0.001) were more frequent in Group B. CONCLUSIONS: In patients with POD1 DFA ≤ 5000, POD3 DFA ≤ 350 may be a practical test to guide safe early drain removal. Further prospective testing may be useful

Tuning optical modes in slab photonic crystal by atomic layer deposition and laser-assisted oxidation

The authors experimentally investigate the effects of atomic layer deposition (ALD) and laser-assisted oxidation on the optical modes in GaAs L3 photonic crystal air-bridge cavities, using layers of InAs quantum dots as internal light source. Four distinct optical mode peaks are observed in the photonic bandgap and they show different wavelength-redshifts (0–6.5 nm) as the photonic crystal surface is coated with an Al2O3 layer (0–5.4 nm thick). Numerical finite-difference time-domain (FDTD) simulations can well-reproduce the experimental result and give insight into the origin of the shifts of modes with different spatial profiles. By combining the ALD coating with in situ laser-assisted oxidation, we are able to both redshift and blueshift the optical modes and we attribute the blueshift to the formation of a GaAs-oxide at the expense of GaAs at the interface between GaAs and the Al2O3 layer. This result can be quantitatively reproduced by including a GaAs-oxide layer into the FDTD model. Selective etching experiments, confirm that this GaAs-oxide layer is mainly at the interface between GaAs and Al2O3 layers

Precision spectroscopy with two correlated atoms

We discuss techniques that allow for long coherence times in laser spectroscopy experiments with two trapped ions. We show that for this purpose not only entangled ions prepared in decoherence-free subspaces can be used but also a pair of ions that are not entangled but subject to the same kind of phase noise. We apply this technique to a measurement of the electric quadrupole moment of the 3d D5/2 state of 40Ca+ and to a measurement of the linewidth of an ultrastable laser exciting a pair of 40Ca+ ions

The Nucleon Spectral Function at Finite Temperature and the Onset of Superfluidity in Nuclear Matter

Nucleon selfenergies and spectral functions are calculated at the saturation density of symmetric nuclear matter at finite temperatures. In particular, the behaviour of these quantities at temperatures above and close to the critical temperature for the superfluid phase transition in nuclear matter is discussed. It is shown how the singularity in the thermodynamic T-matrix at the critical temperature for superfluidity (Thouless criterion) reflects in the selfenergy and correspondingly in the spectral function. The real part of the on-shell selfenergy (optical potential) shows an anomalous behaviour for momenta near the Fermi momentum and temperatures close to the critical temperature related to the pairing singularity in the imaginary part. For comparison the selfenergy derived from the K-matrix of Brueckner theory is also calculated. It is found, that there is no pairing singularity in the imaginary part of the selfenergy in this case, which is due to the neglect of hole-hole scattering in the K-matrix. From the selfenergy the spectral function and the occupation numbers for finite temperatures are calculated.Comment: LaTex, 23 pages, 21 PostScript figures included (uuencoded), uses prc.sty, aps.sty, revtex.sty, psfig.sty (last included

On the `Stationary Implies Axisymmetric' Theorem for Extremal Black Holes in Higher Dimensions

All known stationary black hole solutions in higher dimensions possess additional rotational symmetries in addition to the stationary Killing field. Also, for all known stationary solutions, the event horizon is a Killing horizon, and the surface gravity is constant. In the case of non-degenerate horizons (non-extremal black holes), a general theorem was previously established [gr-qc/0605106] proving that these statements are in fact generally true under the assumption that the spacetime is analytic, and that the metric satisfies Einstein's equation. Here, we extend the analysis to the case of degenerate (extremal) black holes. It is shown that the theorem still holds true if the vector of angular velocities of the horizon satisfies a certain "diophantine condition," which holds except for a set of measure zero.Comment: 30pp, Latex, no figure

Isotopic Scaling of Heavy Projectile Residues from the collisions of 25 MeV/nucleon 86Kr with 124Sn, 112Sn and 64Ni, 58Ni

The scaling of the yields of heavy projectile residues from the reactions of 25 MeV/nucleon 86Kr projectiles with 124Sn,112Sn and 64Ni, 58Nitargets is studied. Isotopically resolved yield distributions of projectile fragments in the range Z=10-36 from these reaction pairs were measured with the MARS recoil separator in the angular range 2.7-5.3 degrees. The velocities of the residues, monotonically decreasing with Z down to Z~26-28, are employed to characterize the excitation energy. The yield ratios R21(N,Z) for each pair of systems are found to exhibit isotopic scaling (isoscaling), namely, an exponential dependence on the fragment atomic number Z and neutron number N. The isoscaling is found to occur in the residue Z range corresponding to the maximum observed excitation energies. The corresponding isoscaling parameters are alpha=0.43 and beta=-0.50 for the Kr+Sn system and alpha=0.27 and beta=-0.34 for the Kr+Ni system. For the Kr+Sn system, for which the experimental angular acceptance range lies inside the grazing angle, isoscaling was found to occur for Z<26 and N<34. For heavier fragments from Kr+Sn, the parameters vary monotonically, alpha decreasing with Z and beta increasing with N. This variation is found to be related to the evolution towards isospin equilibration and, as such, it can serve as a tracer of the N/Z equilibration process. The present heavy-residue data extend the observation of isotopic scaling from the intermediate mass fragment region to the heavy-residue region. Such high-resolution mass spectrometric data can provide important information on the role of isospin in peripheral and mid-peripheral collisions, complementary to that accessible from modern large-acceptance multidetector devices.Comment: 8 pages, 6 figures, submitted to Phys. Rev.

Evidence Vs. Practice in Early Drain Removal Following Pancreatectomy

Background: Early drain removal when postoperative day (POD) 1 drain fluid amylase (DFA) was ≤ 5000 U/L reduced complications in a previous randomized controlled trial. We hypothesized that most surgeons continue to remove drains late and this is associated with inferior outcomes. Methods: We assessed the practice of surgeons in a prospectively maintained pancreas surgery registry to determine the association between timing of drain removal with demographics, co-morbidities, and complications. We selected patients with POD1 DFA ≤ 5000 U/L and excluded those without drains, and subjects without data on POD1 DFA or timing of drain removal. Early drain removal was defined as ≤ POD5. Results: 244 patients met inclusion criteria. Only 90 (37%) had drains removed early. Estimated blood loss was greater in the late removal group (190 mL vs 100 mL, p = 0.005) and pathological findings associated with soft gland texture were more frequent (97(63%) vs 35(39%), p < 0.0001). Patients in the late drain removal group had more complications (84(55%) vs 30(33%), p = 0.001) including pancreatic fistula (55(36%) vs 4(4%), p < 0.0001), delayed gastric emptying (27(18%) vs 3(3%), p = 0.002), and longer length of stay (7 days vs 5 days, p < 0.0001). In subset analysis for procedure type, complications and pancreatic fistula remained significant for both pancreatoduodenectomy and distal pancreatectomy. Conclusion: Despite level 1 data suggesting improved outcomes with early removal when POD1 DFA is ≤ 5000 U/L, experienced pancreas surgeons more frequently removed drains late. This practice was associated with known risk factors (EBL, soft pancreas) and may be associated with inferior outcomes suggesting potential for improvement

Coronal Shock Waves, EUV waves, and Their Relation to CMEs. I. Reconciliation of "EIT waves", Type II Radio Bursts, and Leading Edges of CMEs

We show examples of excitation of coronal waves by flare-related abrupt eruptions of magnetic rope structures. The waves presumably rapidly steepened into shocks and freely propagated afterwards like decelerating blast waves that showed up as Moreton waves and EUV waves. We propose a simple quantitative description for such shock waves to reconcile their observed propagation with drift rates of metric type II bursts and kinematics of leading edges of coronal mass ejections (CMEs). Taking account of different plasma density falloffs for propagation of a wave up and along the solar surface, we demonstrate a close correspondence between drift rates of type II bursts and speeds of EUV waves, Moreton waves, and CMEs observed in a few known events.Comment: 30 pages, 15 figures. Solar Physics, published online. The final publication is available at http://www.springerlink.co