This study demonstrated a significant reduction in common femoral venous flow during laparoscopic cholecystectomy coincident with pneumoperitoneum and reverse Trendelenburg's position. Intermittent sequential pneumatic compression reversed that effect, returning peak systolic velocity to normal.

The free inferior gluteal flap is a major secondary choice of autologous tissue for breast reconstruction if the TRAM flap is not an option. Loss of posterior thigh and popliteal sensibility is a frequent sequela of harvesting the free inferior gluteal musculocutaneous flap and the inferior gluteal artery perforator (I-GAP) flap. The posterior femoral cutaneous nerve of the thigh lies directly on the deep surface of the gluteus maximus muscle, having a very close anatomic relationship with the inferior gluteal artery. The purpose of this study was to gain a better understanding of the anatomy of the posterior femoral cutaneous nerve (PFCN), its branches, and their relationship with the inferior gluteal artery (IGA). Eighteen fresh human pelvic halves were dissected for examination during harvesting of the inferior gluteal myocutaneous free flap, to determine if a nerve-sparing approach was possible and how this information might impact on I-GAP flap harvest. Seventeen of 18 pelvic halves had at least some of the PFCN branches intact after isolation of the IGA pedicle and flap elevation. Three of 18 of the pelvic halves had the entire PFCN and its branches intact after flap elevation. One of 18 pelvic halves required complete transection of the PFCN and its branches in order to isolate the IGA pedicle. In 94.5 percent of the pelvic halve dissections, it was possible to maintain at least a portion of the PFCN intact after isolation of the inferior gluteal artery pedicle while harvesting the free inferior gluteal myocutaneous flap. These findings support a nerve-sparing approach to inferior gluteal myocutaneous flap elevation to minimize the sequela of posterior thigh anesthesia. These data also emphasize the intimate relationship of the PFCN and the gluteal artery and the real possibility of injury to the PFCN during I-GAP harvest.

Time-resolved laser-induced breakdown spectrometry has been combined with the long spark technique and applied to the rapid determination of beryllium in beryllium-copper alloys. A calibration curve was developed which related the beryllium concentration in a solid copper matrix to the Be(I) 234.9-nm to Cu(II) 235.7-nm intensity ratio. The beryllium concentrations ranged from 0.001 to 0.22%. For the lowest concentration the relative standard deviation of replicate samples was 7%, implying a detection limit of 0.0002% (2 ppm) at a signal-to-noise ratio of 3. The excitation temperature was determined from Boltzmann plots on Cu(I) and Cu(II), assuming local thermodynamic equilibrium. The values from the two spectra agreed well, and averaged to 13,850 K at 1 μS into the plasma lifetime.

When lidar pulses travel through a short path that includes a relatively high concentration of aerosols, scattering phenomena can alter the power and temporal properties of the pulses significantly, causing undesirable effects in the received pulse. In many applications the design of the lidar transmitter and receiver must consider adverse environmental aerosol conditions to ensure the desired performance. We present an analytical model of lidar system operation when the optical path includes aerosols for use in support of instrument design, simulations, and system evaluation. The model considers an optical path terminated with a solid object, although it can also be applied, with minor modifications, to cases where the expected backscatter occurs from nonsolid objects. The optical path aerosols are characterized by their attenuation and backscatter coefficients derived by the Mie theory from the concentration and particle size distribution of the aerosol. Other inputs include the lidar system parameters and instrument response function, and the model output is the time-resolved received pulse. The model is demonstrated and experimentally validated with military fog oil smoke for short ranges (several meters). The results are obtained with a lidar system operating at a wavelength of 0.905 microm within and outside the aerosol. The model goodness of fit is evaluated using the statistical coefficient of determination whose value ranged from 0.88 to 0.99 in this study.

Time -resolved laser-induced breakdown spectrometry has been combined with the long spark technique and applied to the rapid determination of beryllium in beryllium-copper alloys. Excitation temperatures within the spark were determined from Boltzmann plots on Cu (I) and Cu (II) lines. The method can be extended to other elements in other matrices, even nonconductors.