Current algorithm for the surgical treatment of facial pain

<p/> <p>Background</p> <p>Facial pain may be divided into several distinct categories, each requiring a specific treatment approach. In some cases, however, such categorization is difficult and treatment is ineffective. We reviewed our extensive clinical experience and designed an algorithmic approach to the treatment of medically intractable facial pain that can be treated through surgical intervention.</p> <p>Methods</p> <p>Our treatment algorithm is based on taking into account underlying pathological processes, the anatomical distribution of pain, pain characteristics, the patient's age and medical condition, associated medical problems, the history of previous surgical interventions, and, in some cases, the results of psychological evaluation. The treatment modalities involved in this algorithm include diagnostic blocks, peripheral denervation procedures, craniotomy for microvascular decompression of cranial nerves, percutaneous rhizotomies using radiofrequency ablation, glycerol injection, balloon compression, peripheral nerve stimulation procedures, stereotactic radiosurgery, percutaneous trigeminal tractotomy, and motor cortex stimulation. We recommend that some patients not receive surgery at all, but rather be referred for other medical or psychological treatment.</p> <p>Results</p> <p>Our algorithmic approach was used in more than 100 consecutive patients with medically intractable facial pain. Clinical evaluations and diagnostic workups were followed in each case by the systematic choice of the appropriate intervention. The algorithm has proved easy to follow, and the recommendations include the identification of the optimal surgery for each patient with other options reserved for failures or recurrences. Our overall success rate in eliminating facial pain presently reaches 96%, which is higher than that observed in most clinical series reported to date</p> <p>Conclusion</p> <p>This treatment algorithm for the intractable facial pain appears to be effective for patients with a wide variety of painful conditions and may be recommended for use in other institutions.</p

Controlled Ecological Life Support Systems (CELSS) physiochemical waste management systems evaluation

Parametric data for six waste management subsystems considered for use on the Space Station are compared, i.e.: (1) dry incineration; (2) wet oxidation; (3) supercritical water oxidation; (4) vapor compression distillation; (5) thermoelectric integrated membrane evaporation system; and (6) vapor phase catalytic ammonia removal. The parameters selected for comparison are on-orbit weight and volume, resupply and return to Earth logistics, power consumption, and heat rejection. Trades studies are performed on subsystem parameters derived from the most recent literature. The Boeing Engineering Trade Study (BETS), an environmental control and life support system (ECLSS) trade study computer program developed by Boeing Aerospace Company, is used to properly size the subsystems under study. The six waste treatment subsystems modeled in this program are sized to process the wastes for a 90-day Space Station mission with an 8-person crew, and an emergency supply period of 28 days. The resulting subsystem parameters are compared not only on an individual subsystem level but also as part of an integrated ECLSS

The Use and Explanation of the Phase Angle in Forced Vibration Testing

Forced vibration testing is a tool used to characterize a structure’s dynamic properties. When subjecting a structure to a forced harmonic load, the results help define the structure’s fundamental frequencies and dominant mode shapes. However, when conducting testing, it is difficult to determine the contributions of each mode to the response at a given location in the structure. The recorded response from a forced vibration test is a combination of unknown modal constituents. Excitation may not result in the pure, single mode response that the experimenter desires, but may instead result in a combination of modal responses that obscure the recorded data or even weaken the overall response. The phase angle is the lag in the response of the structure to the applied harmonic load. Often, engineers focus on the amplitude of the response but overlook the phase angle in their analysis. The investigation conducted herein used a configurable three-story MATLAB model capable of simulating forced vibration tests to determine the role of the phase angle in forced vibration testing. The results produced by the model were also used to analyze modal contributions to the structural response. A data-driven numerical approach and algebraic theoretical approach were both used to characterize the harmonic response. This study describes how the phase angle could indicate when modal contamination occurs, helping engineers filter forced vibration results and understand when a pure mode response is being achieved

Photoionization of Galactic Halo Gas by Old Supernova Remnants

We present new calculations on the contribution from cooling hot gas to the photoionization of warm ionized gas in the Galaxy. We show that hot gas in cooling supernova remnants (SNRs) is an important source of photoionization, particularly for gas in the halo. We find that in many regions at high latitude this source is adequate to account for the observed ionization so there is no need to find ways to transport stellar photons from the disk. The flux from cooling SNRs sets a floor on the ionization along any line of sight. Our model flux is also shown to be consistent with the diffuse soft X-ray background and with soft X-ray observations of external galaxies. We consider the ionization of the clouds observed towards the halo star HD 93521, for which there are no O stars close to the line of sight. We show that the observed ionization can be explained successfully by our model EUV/soft X-ray flux from cooling hot gas. In particular, we can match the H alpha intensity, the S++/S+ ratio, and the C+* column. From observations of the ratios of columns of C+* and either S+ or H0, we are able to estimate the thermal pressure in the clouds. The slow clouds require high (~10^4 cm^-3 K) thermal pressures to match the N(C+*)/N(S+) ratio. Additional heating sources are required for the slow clouds to maintain their ~7000 K temperatures at these pressures, as found by Reynolds, Hausen & Tufte (1999).Comment: AASTeX 5.01; 34 pages, 2 figures; submitted to Astrophysical Journa

Possible Detection of OVI from the LMC Superbubble N70

We present FUSE observations toward four stars in the LMC superbubble N70 and compare these spectra to those of four comparison targets located in nearby field and diffuse regions. The N70 sight lines show OVI 1032 absorption that is consistently stronger than the comparison sight lines by ~60%. We attribute the excess column density (logN_OVI=14.03 cm^-2) to hot gas within N70, potentially the first detection of OVI associated with a superbubble. In a survey of 12 LMC sight lines, Howk et al. (2002a) concluded that there was no correlation between ISM morphology and N_OVI. We present a reanalysis of their measurements combined with our own and find a clear difference between the superbubble and field samples. The five superbubbles probed to date with FUSE show a consistently higher mean N_OVI than the 12 non-superbubble sight lines, though both samples show equivalent scatter from halo variability. Possible ionization mechanisms for N70 are discussed, and we conclude that the observed OVI could be the product of thermal conduction at the interface between the hot, X-ray emitting gas inside the superbubble and the cooler, photoionized material making up the shell seen prominently in Halpha. We calculate the total hydrogen density n_H implied by our OVI measurements and find a value consistent with expectations. Finally, we discuss emission-line observations of OVI from N70.Comment: 9 pages in emulateapj style. Accepted to Ap

A Comparison Of Five Mechanical Work Algorithms For Different Footstrike Patterns And Speeds During Distance Running

The mechanical work done by a runner during an average stride cyde has been calculated with a variety of algorithms that generate values that may vary by an order of magnitude. The application of different algorithms to the same data set is uncommon, and does not seem to have been used at all to compare different foot strike patterns (FSP) during distance running. Average stride cycle values from five work algorithms for forefoot strike (ffs) and heel strike (hs) running at three different running speeds are presented. In general order from most to least restrictive: Wn allows no transfer between segments; Ww, within-segment transfer only; WwbAS, transfer within and between adjacent segments only; WwbLT, within and between segments of the same limb and the trunk; and, Wwb, within- and between-segment transfer with no restrictions. The primary difference in these algorithms is the amount of energy transfer they permit between and among body segments. Twelve highly skilled, male distance runners each ran with both FSP at three speeds ranging from 3.58 to 4.58 m-s-l. High-speed video (200 Hz) was used to track eight segment endpoint markers in the left sagittal plane. An ll-segment model was used with symmetry assumed to generate right side values. Among the algorithms, the no-transfer method (Wn) produced the highest work estimates. An absolute difference of -300 joules-stride-1 (-15-20%) existed across speeds between the no-transfer and within-transfer algorithms. There was then a relatively large decrease to the span of values generated from the other three algorithms. WwbAS was slightly higher than the remaining two algorithms, moreso in relative terms as speed increased. WwbLT increased slightly over speed (-40% slow->fast), while Wwb, the least restrictive, demonstrated almost no change across speeds (-1 % slow->fast). On average, these differences converged absolutely (75->20 joules-stride-1) and relatively (9.8%->2.5%) with increased speed; i.e., differences between the two .FSP decreased as speed increased. At all speeds for each algorithm, hs was lower than ffs. Collapsed across speeds, hs as percentage of ffs was 96.7 (Wn), 96.5 (ww)- 96.7 (WwbAS), 95.8 (WwbLT) and 89.4% (Wwb). Wwb across speeds consistently showed the largest relative differences between FSP, due perhaps in part to low absolute values. However, FSP differences still decreased with increased speed. This algorithm, therefore, appears to preserve the ordinal relationship and the trend in relative change between FSP across speeds reflected in the other four algorithms. Overall, the consistency across all algorithms of absolute and relative decrease between FSP with increased speed suggests variations in actual kinematics, not algorithms, are responsible for observed differences

Solar wind-magnetosphere coupling and the distant magnetotail: ISEE-3 observations

ISEE-3 Geotail observations are used to investigate the relationship between the interplanetary magnetic field, substorm activity, and the distant magnetotail. Magnetic field and plasma observations are used to present evidence for the existence of a quasi-permanent, curved reconnection neutral line in the distant tail. The distance to the neutral line varies from absolute value of X = 120 to 140 R/sub e near the center of the tail to beyond absolute value of X = 200 R/sub e at the flanks. Downstream of the neutral line the plasma sheet magnetic field is shown to be negative and directly proportional to negative B/sub z in the solar wind as observed by IMP-8. V/sub x in the distant plasma sheet is also found to be proportional to IMF B/sub z with southward IMF producing the highest anti-solar flow velocities. A global dayside reconnection efficiency of 20 +- 5% is derived from the ISEE-3/IMP-8 magnetic field comparisons. Substorm activity, as measured by the AL index, produces enhanced negative B/sub z and tailward V/sub x in the distant plasma sheet in agreement with the basic predictions of the reconnection-based models of substorms. The rate of magnetic flux transfer out of the tail as a function of AL is found to be consistent with previous near-Earth studies. Similarly, the mass and energy fluxes carried by plasma sheet flow down the tail are consistent with theoretical mass and energy budgets for an open magnetosphere. In summary, the ISEE-3 Geotail observations appear to provide good support for reconnection models of solar wind-magnetosphere coupling and substorm energy rates

Stochastic theory of spin-transfer oscillator linewidths

We present a stochastic theory of linewidths for magnetization oscillations in spin-valve structures driven by spin-polarized currents. Starting from a nonlinear oscillator model derived from spin-wave theory, we derive Langevin equations for amplitude and phase fluctuations due to the presence of thermal noise. We find that the spectral linewidths are inversely proportional to the spin-wave intensities with a lower bound that is determined purely by modulations in the oscillation frequencies. Reasonable quantitative agreement with recent experimental results from spin-valve nanopillars is demonstrated.Comment: Submitted to Physical Review