In vitro activity of 9 antibiotics and 3 beta-lactamase inhibitors against 107 clinical isolates of Acinetobacter baumanii

Twenty eight of 227 patients undergoing restorative proctocolectomy for inflammatory bowel disease, familial adenomatous polyposis or functional disease were over the age of 50 years: ages 50 to 60 (n = 13), 60 to 70 (n = 10), and over 70 (n = 5). Major complications occurred in 5 patients over the age of 50 (18%) compared with 43 patients under the age of 50 (23%). Three patients above the age of 50 had their pouch excised (11%) compared with 23 under the age of 50 (12%). Functional outcome was assessed with a 12 point symptom score. This was similar in all age bands: under 50 years (mean = 2.2; sd +/- 2.2; n = 109), 50 to 60 years (mean = 2.5; sd +/- 2.5; n = 12), 60 to 70 years (mean = 2.8; sd +/- 2.3; n = 7) and over 70 years (mean = 4.0; sd +/- 3.7; n = 5): P > 0.05). When analysed for ulcerative colitis alone, no significant differences were seen between the two age groups. Restorative proctocolectomy in the elderly gives results which are comparable to the younger population.     

Measurement of IP3 in p-i-n photodetectors and proposed performancerequirements for RF fiber-optic links

The nonlinearities generated by wide-band, high-current photodetectors are discussed in the context of the performance of an externally modulated analog radio-frequency fiber-optic link. The quantitative impart of the detector's third-order intermodulation product intercept (IP3) on the link's spur-free dynamic range is analyzed. Waveguide p-i-n photodiodes were developed to specifically address these stringent IP3 goals. The IP3 was measured using a four laser heterodyne system resulting in an IP3 of 27 dBm measured at a center frequency of 20 GHz with 20 mA of de photocurrent. The authors believe that this is the highest photodetector IP3 reported to date at these operating conditions     

Compressibility effects on outflows in a two-fluid system. 1. Line source in cylindrical geometry

A two-dimensional line source outflow is considered, in which the evolution of a sharp interface separating an incompressible fluid from a bounding weakly compressible gas is analysed. Linear theory is applied, assuming that anisotropies in the source outflow are small, to develop an approximate solution for the interfacial evolution. The simplest solutions to the governing linearised equations require the presence of a high-order velocity singularity at the location of the line source. A spectral method is also developed to capture the nonlinear behaviour of the flow; after some finite time, curvature singularities are found to develop on the interface. Comparisons are made between the stability of the interface and its analogue which separates two incompressible fluids. It is found that when the bounding fluid is weakly compressible rather than incompressible, the stability of the interface is significantly increased.     

Dual-channel strained-layer in GaAs-GaAs-AlGaAs WDM source withintegrated coupler by selective-area MOCVD

Selective-area metalorganic chemical vapor deposition is used to fabricate a dual-channel strained-layer InGaAs-GaAs-AlGaAs WDM source with integrated coupler. Threshold currents of 11.5 mA were obtained for 1100 μm long uncoated channels operating cw at room temperature. Both channels can be coupled into a single mode fiber without the need for an external coupler     

Application of the MOSFET device structure in characterizing imperfection centers in indium-doped silicon

C.T. Sah has published a review article demonstrating the application of high-frequency small signal capacitance and current transients of a space charge layer. Application of such transients is a powerful technique in characterizing deep level imperfection center concentrations, energy levels, thermal and optical emission rates and thermal capture cross sections. The MOSFET device structure is particularly convenient for low temperature measurements of shallow levels where deionization occurs and the substrate becomes highly resistive, seriously limiting capacitance transient techniques. Examples are given by results on indium-doped silicon, such as employed in extrinsic IR detectors. The emission time constant of holes from the neutral indium center has been found to depend on the indium doping. Measurements on lightly doped samples yield a value for the emission rate, $\text{1}\text{e}{}_{\mathrm{p}}$, of 6.0 msec at 77°K and a thermal activation energy of 0.15 eV. Measurements on heavily doped samples yield values of $\text{1}\text{e}{}_{\mathrm{p}}$ of 20 μsec at 77°K and an activation energy of 0.117 eV. These results are consistent with the Poole-Frenkel effect describing field enhanced thermal emission of holes from the indium center. Measurements of the hole capture coefficient at 77°K yield values for c_p of 3.7 × 10^?7 cm³/sec. These measurements have been made on heavily doped samples. The capture coefficient measured is the zero field or quasi-equilibrium value. The temperature dependence of the hole capture coefficient has been found to be T^?4. Small transients in the thermal emission rate measurements have been observed. These transients have thermal activation energies of around 0.08 eV and are associated with the 0.11 eV level as reported by Hughes Research Labs after accounting for barrier lowering by the Poole-Frenkel effect.     

Macrophage and myofibroblast involvement in ischemic acute renal failure is attenuated by endothelin receptor antagonists

BACKGROUND: Endothelin (ET) may be a mediator of injury following ischemia-induced acute renal failure (ARF). ET receptor (ETR) antagonists have been reported to increase survival rates and lower serum creatinines when administered postrenal ischemia-reperfusion injury in the rat. Renal cellular and extracellular matrix responses to this therapy have not been addressed. METHODS: We investigated the use of ETR antagonists, PD 156707 (ETA) and SB 209670 (ETA and ETB) in the treatment of sublethal postischemic ARF. The right kidney of female Sprague-Dawley rats weighing approximately 200 g was removed. After five days, the left renal pedicle was occluded for 45 minutes. Twenty-four hours after renal ischemia, one of two ETR antagonists, PD 156707 (N = 7) or SB 209670 (N = 8), was administered. Experimental animals were compared with an ischemic group receiving only saline (N = 9). Three nephrectomized groups that did not undergo ischemia but that received infusions of saline (N = 6), PD 156707 (N = 6), and SB 209670 (N = 6), respectively, were also studied. Animals were sacrificed one week postischemia. Quantitation of monocytes and macrophages (Mo/Mphi), alpha-smooth muscle actin-positive myofibroblasts, and collagens type III and IV was performed by immunohistochemical staining. Cell kinetics were examined by staining for apoptosis with terminal deoxyuridine triphosphate (dUTP) nick end labeling and for proliferation with proliferating cell nuclear antigen. RESULTS: All ischemic groups of rats initially developed raised serum creatinine levels; however, no significant difference was observed between the groups (Kruskal-Wallis). Creatinines returned to preischemic values in all groups by the time of sacrifice. No significant difference in kidney weights or body weights was found between groups. Histologically, infiltration of Mo/Mphi was significantly reduced in groups treated with ETR antagonists (P < 0.001). The presence of myofibroblasts was also significantly reduced in the antagonist-treated groups (P < 0. 001). This was also paralleled by reduced quantities of collagen IV in the treated rat groups (P < 0.001). The interstitial area was also significantly greater in the saline group (P < 0.001). The amount of collagen III did not significantly differ between rat groups. Apoptosis was reduced (P < 0.001) by treatment with ETR antagonists, whereas proliferation was enhanced (P < 0.005). All non-ischemic groups showed no variation in any parameter studied at this time point. CONCLUSIONS: Treatment of ischemic ARF in the rat with ETR antagonists PD 156707 and SB 209670 attenuated cellular infiltration and matrix accumulation. An advantage of one antagonist over the other could not be determined in this study. The marked discrepancy between function and pathology (former unchanged, latter markedly improved) may be due to the time frame of this experiment, and longer outcome measures need to be assessed.