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Sample records for extreme decompression rates

  1. Surgical decompression in lower-extremity diabetic peripheral neuropathy.

    PubMed

    Rader, Andrew J

    2005-01-01

    Peripheral neuropathy can be a devastating complication of diabetes mellitus. This article describes surgical decompression as a means of restoring sensation and relieving painful neuropathy symptoms. A prospective study was performed involving patients diagnosed as having type 1 or type 2 diabetes with lower-extremity peripheral neuropathy. The neuropathy diagnosis was confirmed using quantitative sensory testing. Visual analog scales were used for subjective assessment before and after surgery. Treatment consisted of external and as-needed internal neurolysis of the common peroneal, deep peroneal, tibial, medial plantar, lateral plantar, and calcaneal nerves. Subjective pain perception and objective sensibility were significantly improved in most patients who underwent the described decompression. Surgical decompression of multiple peripheral nerves in the lower extremities is a valid and effective method of providing symptomatic relief of neuropathy pain and restoring sensation. PMID:16166461

  2. Effects of State and Decompression Rate on the Decompressive Response of Volatile- and Crystal-Bearing Analogue Magmas.

    NASA Astrophysics Data System (ADS)

    Spina, L.; Cimarelli, C.; Scheu, B.; Dingwell, D. B.

    2014-12-01

    Volcanic eruptive styles are influenced both by the physical properties of the ascending magma as well as the decompression rates involved. Systematic experimental investigations of both state and rate have been performed here on analogue basaltic systems. Controlled decompression experiments were performed in a shock tube system, using a silicon oil basis as the basalt proxy. The samples were saturated with 10 MPa of Ar for 72h, followed by controlled decompression. Four series of experiments were performed: 1) Pure liquids with viscosities ranging from 1 to 1000 Pa s were used to map the liquid response. 2) Micrometric spherical particles were added to the liquid to evaluate the effect of crystal fraction. 3) The role of crystal shape was examined by using particles with different aspect ratios. 4) Finally, the effects of saturation time and of pressure were examined via a series of experiments at 24 h, performed over a range of saturation pressure. The dynamics of foaming and flow of the bubbly fluid during decompression were constrained using image analysis, by measuring the height of the expanding column, as well as analyzing the bubble size distribution. At the onset a delayed nucleation event is observed. When the amount of nucleated bubbles approaches a critical thickness, a foam develops. Finally, the foam reaches equilibrium, and starts oscillating in response to the balance between foam disruption and growth. These observation may have important implications for oscillatory eruptive phenomena observed in active volcanoes (i.e. gas piston activity). Finally, the effect of crystals was investigated. In their presence, heterogeneous nucleation enhances the number of bubble nuclei, even at low crystal fractions. As a consequence, the foam develops earlier, and is able to ascend with major upward speed, in comparison to the pure oil. Experimental decompression of silicon oil has proven to be a unique tool to unravel the hidden dynamics of magma into the

  3. Gas bubbles in rats after heliox saturation and different decompression steps and rates.

    PubMed

    Skogland, Steffen; Segadal, Kåre; Sundland, Harald; Hope, Arvid

    2002-06-01

    Effects of pressure reduction, decompression rate, and repeated exposure on venous gas bubble formation were determined in five groups (GI, GII, GIII, GIV, and GV) of conscious and freely moving rats in a heliox atmosphere. Bubbles were recorded with a Doppler ultrasound probe implanted around the inferior caval vein. Rats were held for 16 h at 0.4 MPa (GI), 0.5 MPa (GII and GIII), 1.7 MPa (GIVa), or 1.9 MPa (GIV and GV), followed by decompression to 0.1 MPa in GI to GIII and to 1.1 MPa in GIV and GV. A greater decompression step, but at the same rate (GII vs. GI and GIVb vs. GIVa), resulted in significantly more bubbles (P < 0.01). A twofold decompression step resulted in equal amount of bubbles when decompressing to 1.1 MPa compared with 0.1 MPa. The faster decompression in GII and GVa (10.0 kPa/s) resulted in significantly more bubbles (P < 0.01) compared with GIII and GVb (2.2 kPa/s). No significant difference was observed in cumulative bubble score when comparing first and second exposure. With the present animal model, different decompression regimes may be evaluated. PMID:12015383

  4. Calculation of Decompression Rates for the Initial Explosive Phase of the 2010 Merapi Eruption

    NASA Astrophysics Data System (ADS)

    Matthews, E.; Genareau, K. D.

    2015-12-01

    The 2010 eruption of Merapi (Java, Indonesia) initiated with an uncharacteristic explosion, followed by rapid lava dome growth and collapse, all of which generated deadly pyroclastic density currents (PDCs). PDC samples from the initial explosion on October 26th were collected from several locations surrounding the edifice. Plagioclase phenocrysts represent the primary component of the dominant ash mode due to the elutriation of the finer ash fraction during PDC transport. Secondary electron images of 45 phenocrysts were taken using the scanning electron microscope (SEM) to examine preserved glass coatings on phenocrysts, which represent the interstitial melt within the magma at the point of fragmentation. Using these images, the bubble number densities (BNDs) were determined, and the decompression rate meter of Toramaru (2006) was used to calculate the decompression rate during the initial explosion of the 2010 Merapi eruption. Calculated decompression rates range from 6.08x10^7 Pa/s to 1.4x10^8 Pa/s. Decompression rates have shown to correlate with eruption column height; therefore Merapi's rates should be similar to those of other Vulcanian explosions, because the eruption column was 8-9 km in height. The decompression rates acquired for Merapi using Toramaru's BND meter are higher than the rates calculated with other methods such as microlite number density and extension cracks in crystals. Sakurajima volcano (Japan) experienced decompression rates from 7.0 × 10^3 to 7.8 × 10^4 Pa/s during the later phase of the fall 2011 Vulcanian explosions. Plinian explosions, such as at the 1991 eruption of Mt. Pinatubo and the 1980 eruption of St. Helens had much higher column heights compared to the initial 2010 Merapi explosion; 35 km, 19 km, and 8-9 km, respectively, but decompression rates in a comparative range (10^8 Pa/s). Higher decompression rates during the 2010 initial explosion at Merapi likely resulted from increased overpressure in the shallow conduit, the

  5. General Purpose Graphics Processing Unit Based High-Rate Rice Decompression and Reed-Solomon Decoding.

    SciTech Connect

    Loughry, Thomas A.

    2015-02-01

    As the volume of data acquired by space-based sensors increases, mission data compression/decompression and forward error correction code processing performance must likewise scale. This competency development effort was explored using the General Purpose Graphics Processing Unit (GPGPU) to accomplish high-rate Rice Decompression and high-rate Reed-Solomon (RS) decoding at the satellite mission ground station. Each algorithm was implemented and benchmarked on a single GPGPU. Distributed processing across one to four GPGPUs was also investigated. The results show that the GPGPU has considerable potential for performing satellite communication Data Signal Processing, with three times or better performance improvements and up to ten times reduction in cost over custom hardware, at least in the case of Rice Decompression and Reed-Solomon Decoding.

  6. Extreme Decompression-induced Crystallization During the 2004-present Eruption of Mount St. Helens Implications for Shallow Deformation Mechanisms

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.; Pallister, J. S.; Thornber, C. R.

    2006-12-01

    Decompression-induced crystallization may control both the ascent rate and eruption style of hydrous magmas. While rapid magma evacuation accompanying plinian eruptions can transfer magma from storage regions to the surface with little modification other than degassing, slow to moderate rates of magma ascent permit efficient degassing and crystallization of both phenocryst (particularly plagioclase) and groundmass phases. In the extreme, very slow magma ascent leads to complete solidification of magma within the conduit, forming either plugs or large spines. Seven such spines extruded from Mount St. Helens from 2004 to present are remarkable for their carapaces of striated fault gouge. Examination of individual outcrops shows transitions from competent flow banded dacite to breccia, cataclasite, to finely comminuted and variably consolidated gouge. Field, hand specimen, and thin section observations of these cataclastic dome facies provide new constraints on interactions between rates of magma ascent, degassing, crystallization, and brittle fragmentation, interactions that control the dynamics of lava extrusion. Within the gouge zone, dome fragments are holocrystalline as the result of complete solidification along conduit margins prior to brittle fragmentation. Sequential breakage along the margin then created zones of breccia, cataclasite, and powdery fault gouge. Continued slip created narrow slickenside planes within the gouge that comprise thin (1 mm) zones of foliated ultracataclasite. The grain size reduction along these slip zones, the entrainment of shattered grains into foliated bands, and the rounding and abrasion of larger clasts outside the slickenside planes, show that the gouge zone developed as the result of large shear strains along the conduit margin. This inference is reasonable given a solidification depth of 400-500 m (estimated from experimental phase relations), above which brittle deformation was concentrated along the conduit margin. Near

  7. Risk of decompression sickness in extreme human breath-hold diving.

    PubMed

    Fitz-Clarke, J R

    2009-01-01

    The risk of decompression sickness (DCS) in human breath-hold diving is expected to increase as dives progress deeper until a depth is reached where total lung collapse stops additional nitrogen gas uptake. We assembled a database of all documented human breath-hold dives to 100 metres or greater, including both practice and record dives. Between 1976 and 2006 there were 192 such dives confirmed by 24 divers (18 male, 6 female). The deepest dive was to 209 metres. There were two drowning fatalities, and two cases ofDCS. Depth-time risk estimates for DCS were derived for single breath-hold dives by modifying probabilistic decompression models calibrated with data from short deep no-stop air dives and submarine escape trials using maximum-likelihood estimation. Arterial nitrogen levels during apnea were adjusted for lung compression and decreased cardiac output. Predicted DCS risk is negligible up to about 100 metres, beyond which risk increases nonlinearly and reaches a plateau around 5 to 7 percent when total lung collapse occurs beyond 230 metres. Results are consistent with data available from deep breath-hold dives. PMID:19462748

  8. [Decompression sickness].

    PubMed

    Sipinen, Seppo

    2010-01-01

    Decompression sickness will develop, when excess concentrations of nitrogen or helium from the respiratory gas have dissolved into the body. The dissolved gases are removed from the body with exhalation. If the level of dissolved gases exceeds their natural rate of removal, bubbles are formed in the circulation and tissues as the pressure surrounding the diver decreases. The bubbles will cause decompression sickness typically manifested as skin symptoms, musculoskeletal pains and disturbances of the central nervous system. The only known and effective treatment is recompression and inhalation of pure oxygen. PMID:20486494

  9. The effects of different rates of ascent on the incidence of altitude decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.

    1989-01-01

    The effect of different rates of ascent on the incidence of altitude decompression sickness (DCS) was analyzed by a retrospective study on 14,123 man-flights involving direct ascent up to 38,000 ft altitude. The data were classified on the basis of altitude attained, denitrogenation at ground level, duration of stay at altitude, rest or exercise while at altitude, frequency of exercise at altitude, and ascent rates. This database was further divided on the basis of ascent rates into different groups from 1000 ft/min up to 53,000 ft/min. The database was analyzed using multiple correlation and regression methods, and the results of the analysis reveal that ascent rates influence the incidence of DCS in combination with the various factors mentioned above. Rate of ascent was not a significant predictor of DCS and showed a low, but significant multiple correlation (R=0.31) with the above factors. Further, the effects of rates below 2500 ft/min are significantly different from that of rates above 2500 ft/min on the incidence of symptoms (P=0.03) and forced descent (P=0.01). At rates above 2500 ft/min and up to 53,000 ft/min, the effects of ascent rates are not significantly different (P greater than 0.05) in the population examined while the effects of rates below 2500 ft/min are not clear.

  10. Illustration of Cost Saving Implications of Lower Extremity Nerve Decompression to Prevent Recurrence of Diabetic Foot Ulceration

    PubMed Central

    Rankin, Timothy M.; Miller, John D.; Gruessner, Angelika C.; Nickerson, D. Scott

    2015-01-01

    The US diabetic foot ulcer (DFU) incidence is 3-4% of 22.3 million diagnosed diabetes cases plus 6.3 million undiagnosed, 858 000 cases total. Risk of recurrence after healing is 30% annually. Lower extremity multiple nerve decompression (ND) surgery reduces neuropathic DFU (nDFU) recurrence risk by >80%. Cost effectiveness of hypothetical ND implementation to minimize nDFU recurrence is compared to the current $6.171 billion annual nDFU expense. A literature review identified best estimates of annual incidence, recurrence risk, medical management expense, and noneconomic costs for DFU. Illustrative cost/benefit calculations were performed assuming widespread application of bilateral ND after wound healing to the nDFU problem, using Center for Medicare Services mean expense data of $1143/case for unilateral lower extremity ND. Calculations use conservative, evidence-based cost figures, which are contemporary (2012) or adjusted for inflation. Widespread adoption of ND after nDFU healing could reduce annual DFU occurrences by at least 21% in the third year and 24% by year 5, representing calculated cost savings of $1.296 billion (year 3) to $1.481 billion (year 5). This scenario proffers significant expense reduction and societal benefit, and represents a minimum 1.9× return on the investment cost for surgical treatment. Further large cost savings would require reductions in initial DFU incidence, which ND might achieve by selective application to advanced diabetic sensorimotor polyneuropathy (DSPN). By minimizing the contribution of recurrences to yearly nDFU incidence, ND has potential to reduce by nearly $1 billion the annual cost of DFU treatment in the United States. PMID:26055081

  11. Illustration of Cost Saving Implications of Lower Extremity Nerve Decompression to Prevent Recurrence of Diabetic Foot Ulceration.

    PubMed

    Rankin, Timothy M; Miller, John D; Gruessner, Angelika C; Nickerson, D Scott

    2015-07-01

    The US diabetic foot ulcer (DFU) incidence is 3-4% of 22.3 million diagnosed diabetes cases plus 6.3 million undiagnosed, 858 000 cases total. Risk of recurrence after healing is 30% annually. Lower extremity multiple nerve decompression (ND) surgery reduces neuropathic DFU (nDFU) recurrence risk by >80%. Cost effectiveness of hypothetical ND implementation to minimize nDFU recurrence is compared to the current $6.171 billion annual nDFU expense. A literature review identified best estimates of annual incidence, recurrence risk, medical management expense, and noneconomic costs for DFU. Illustrative cost/benefit calculations were performed assuming widespread application of bilateral ND after wound healing to the nDFU problem, using Center for Medicare Services mean expense data of $1143/case for unilateral lower extremity ND. Calculations use conservative, evidence-based cost figures, which are contemporary (2012) or adjusted for inflation. Widespread adoption of ND after nDFU healing could reduce annual DFU occurrences by at least 21% in the third year and 24% by year 5, representing calculated cost savings of $1.296 billion (year 3) to $1.481 billion (year 5). This scenario proffers significant expense reduction and societal benefit, and represents a minimum 1.9× return on the investment cost for surgical treatment. Further large cost savings would require reductions in initial DFU incidence, which ND might achieve by selective application to advanced diabetic sensorimotor polyneuropathy (DSPN). By minimizing the contribution of recurrences to yearly nDFU incidence, ND has potential to reduce by nearly $1 billion the annual cost of DFU treatment in the United States. PMID:26055081

  12. Magmatic storage conditions, decompression rate, and incipient caldera collapse of the 1902 eruption of Santa Maria Volcano, Guatemala

    NASA Astrophysics Data System (ADS)

    Andrews, Benjamin J.

    2014-08-01

    Phase equilibria experiments and analysis of natural pumice and phenocryst compositions indicate the 1902 Santa Maria dacite was stored at ~ 140-170 MPa and 840-850 °C prior to eruption. H2O-saturated, cold-seal experiments conducted in vessels with an intrinsic log fO2 of NNO + 1 ± 0.5 show that the natural phase assemblage (melt + plagioclase + amphibole + orthopyroxene + Fe-Ti oxides + apatite) is stable from approximately 115-140 MPa at temperatures below ~ 825 °C, to ~ 840-860 °C at 150 MPa, to > 850 and < 875 °C at 200 MPa. Natural plagioclase phenocrysts have rim compositions that range from An40-An45; this range of compositions defines a ~ 20 °C band that intersects the stable phase assemblage at ~ 150 MPa and 850 °C. Plagioclase hosted melt inclusions were analyzed using FTIR and commonly contain < 5 wt.% H2O, which corresponds to a pressure of ~ 170 MPa at 850 °C, under pure H2O saturated conditions. Amphibole geothermobarometry (Ridolfi et al., 2010) applied to experimental samples suggest two populations of amphiboles, phenocrysts grown during the experiments and inherited xenocrysts, but the pressure-temperature conditions returned by the geothermobarometer are routinely > 50 MPa and > 50 °C greater than experimental run conditions; precise estimates of magmatic conditions based solely upon amphibole composition are likely inaccurate. The experimental results and analysis of natural crystals suggest that although the natural amphiboles likely record a broad range of magmatic conditions, only the lower bounds of that range reflect pre-eruptive storage conditions. Comparison of Santa Maria microlite abundances with decompression experiments examining other silicic systems from the literature suggests that the 1902 dacite decompressed at the rate of ~ 0.005 to 0.01 MPa/s during the eruption. Applying the decompression rate with the previously described eruption rate of approximately 2-3 × 108 kg/s (Williams and Self, 1983; Carey and Sparks, 1986

  13. Decompression illness.

    PubMed

    Vann, Richard D; Butler, Frank K; Mitchell, Simon J; Moon, Richard E

    2011-01-01

    Decompression illness is caused by intravascular or extravascular bubbles that are formed as a result of reduction in environmental pressure (decompression). The term covers both arterial gas embolism, in which alveolar gas or venous gas emboli (via cardiac shunts or via pulmonary vessels) are introduced into the arterial circulation, and decompression sickness, which is caused by in-situ bubble formation from dissolved inert gas. Both syndromes can occur in divers, compressed air workers, aviators, and astronauts, but arterial gas embolism also arises from iatrogenic causes unrelated to decompression. Risk of decompression illness is affected by immersion, exercise, and heat or cold. Manifestations range from itching and minor pain to neurological symptoms, cardiac collapse, and death. First-aid treatment is 100% oxygen and definitive treatment is recompression to increased pressure, breathing 100% oxygen. Adjunctive treatment, including fluid administration and prophylaxis against venous thromboembolism in paralysed patients, is also recommended. Treatment is, in most cases, effective although residual deficits can remain in serious cases, even after several recompressions. PMID:21215883

  14. Failure rates and complications of interspinous process decompression devices: a European multicenter study.

    PubMed

    Gazzeri, Roberto; Galarza, Marcelo; Neroni, Massimiliano; Fiore, Claudio; Faiola, Andrea; Puzzilli, Fabrizio; Callovini, Giorgio; Alfieri, Alex

    2015-10-01

    OBJECT Spacers placed between the lumbar spinous processes represent a promising surgical treatment alternative for a variety of spinal pathologies. They provide an unloading distractive force to the stenotic motion segment, restoring foraminal height, and have the potential to relieve symptoms of degenerative disc disease. The authors performed a retrospective, multicenter nonrandomized study consisting of 1108 patients to evaluate implant survival and failure modes after the implantation of 8 different interspinous process devices (IPDs). METHODS The medical records of patients who had undergone placement of an IPD were retrospectively evaluated, and demographic information, diagnosis, and preoperative pain levels were recorded. Preoperative and postoperative clinical assessments in the patients were based on the visual analog scale. A minimum of 3 years after IPD placement, information on long-term outcomes was obtained from additional follow-up or from patient medical and radiological records. RESULTS One thousand one hundred eight patients affected by symptomatic 1- or 2-level segmental lumbar spine degenerative disease underwent placement of an IPD. The complication rate was 7.8%. There were 27 fractures of the spinous process and 23 dura mater tears with CSF leakage. The ultimate failure rate requiring additional surgery was 9.6%. The reasons for revision, which always involved removal of the original implant, were acute worsening of low-back pain or lack of improvement (45 cases), recurrence of symptoms after an initial good outcome (42 cases), and implant dislocation (20 cases). CONCLUSIONS The IPD is not a substitute for a more invasive 3-column fusion procedure in cases of major instability and spondylolisthesis. Overdistraction, poor bone density, and poor patient selection may all be factors in the development of complications. Preoperatively, careful attention should be paid to bone density, appropriate implant size, and optimal patient selection

  15. Extreme-value dependence: An application to exchange rate markets

    NASA Astrophysics Data System (ADS)

    Fernandez, Viviana

    2007-04-01

    Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations.

  16. Lethality and injuring the effect of compression and decompression rates of high hydrostatic pressure on Escherichia coli O157:H7 in different matrices

    NASA Astrophysics Data System (ADS)

    Syed, Qamar Abbas; Buffa, Martin; Guamis, Buenaventura; Saldo, Jordi

    2013-03-01

    The effect of compression and decompression rates of high hydrostatic pressure (HHP) on Escherichia coli O157:H7 was investigated. Samples of orange juice, skimmed milk and Tris buffer were inoculated with E. coli O157:H7 and subjected to 600 MPa for 3 min at 4°C with fast, medium and slow compression and decompression. Analyses immediately after HHP treatment revealed that E. coli in milk and juice treated with fast compression suffered more than slow compression rates. Slow decompression resulted in higher inactivation of E. coli in all matrices. After overnight storage, highest stress-recovery (1.19 log cfu/mL) was observed in Tris buffer. Healthy cells were<1 log cfu/mL in milk and buffer samples, but no growth was detected in orange juice for any of the treatments immediately after HHP. After 15 days at 4°C, E. coli cells in skimmed milk and Tris buffer recovered significantly, whereas the recovery of sublethally injured cells was inhibited in orange juice.

  17. Recurrent Keratocystic Odontogenic Tumor After Effective Decompression.

    PubMed

    Zhang, Qian; Li, Wei; Han, Fangkai; Huang, Xiaofeng; Yang, Xudong

    2016-07-01

    Keratocystic odontogenic tumor (KCOT) has potential aggressive and infiltrative behavior. Decompression has been widely preferred for large KCOTs due to safety and lower recurrence rates. However, KCOT is still likely to recur even after effective decompression. Here, we present a rare and interesting case of recurrent KCOT after effective decompression with adjunctive enucleation. Redecompression was then performed again, and the effect was still satisfactory on long-term follow-up. PMID:27391520

  18. Cardiopulmonary Changes with Moderate Decompression in Rats

    NASA Technical Reports Server (NTRS)

    Robinson, R.; Little, T.; Doursout, M.-F.; Butler, B. D.; Chelly, J. E.

    1996-01-01

    Sprague-Dawley rats were compressed to 616 kPa for 120 min then decompressed at 38 kPa/min to assess the cardiovascular and pulmonary responses to moderate decompression stress. In one series of experiments the rats were chronically instrumented with Doppler ultrasonic probes for simultaneous measurement of blood pressure, cardiac output, heart rate, left and right ventricular wall thickening fraction, and venous bubble detection. Data were collected at base-line, throughout the compression/decompression protocol, and for 120 min post decompression. In a second series of experiments the pulmonary responses to the decompression protocol were evaluated in non-instrumented rats. Analyses included blood gases, pleural and bronchoalveolar lavage (BAL) protein and hemoglobin concentration, pulmonary edema, BAL and lung tissue phospholipids, lung compliance, and cell counts. Venous bubbles were directly observed in 90% of the rats where immediate post-decompression autopsy was performed and in 37% using implanted Doppler monitors. Cardiac output, stroke volume, and right ventricular wall thickening fractions were significantly decreased post decompression, whereas systemic vascular resistance was increased suggesting a decrease in venous return. BAL Hb and total protein levels were increased 0 and 60 min post decompression, pleural and plasma levels were unchanged. BAL white blood cells and neutrophil percentages were increased 0 and 60 min post decompression and pulmonary edema was detected. Venous bubbles produced with moderate decompression profiles give detectable cardiovascular and pulmonary responses in the rat.

  19. Solidification at the High and Low Rate Extreme

    SciTech Connect

    Halim Meco

    2004-12-19

    The microstructures formed upon solidification are strongly influenced by the imposed growth rates on an alloy system. Depending on the characteristics of the solidification process, a wide range of growth rates is accessible. The prevailing solidification mechanisms, and thus the final microstructure of the alloy, are governed by these imposed growth rates. At the high rate extreme, for instance, one can have access to novel microstructures that are unattainable at low growth rates. While the low growth rates can be utilized for the study of the intrinsic growth behavior of a certain phase growing from the melt. Although the length scales associated with certain processes, such as capillarity, and the diffusion of heat and solute, are different at low and high rate extremes, the phenomena that govern the selection of a certain microstructural length scale or a growth mode are the same. Consequently, one can analyze the solidification phenomena at both high and low rates by using the same governing principles. In this study, we examined the microstructural control at both low and high extremes. For the high rate extreme, the formation of crystalline products and factors that control the microstructure during rapid solidification by free-jet melt spinning are examined in Fe-Si-B system. Particular attention was given to the behavior of the melt pool at different quench-wheel speeds. Since the solidification process takes place within the melt-pool that forms on the rotating quench-wheel, we examined the influence of melt-pool dynamics on nucleation and growth of crystalline solidification products and glass formation. High-speed imaging of the melt-pool, analysis of ribbon microstructure, and measurement of ribbon geometry and surface character all indicate upper and lower limits for melt-spinning rates for which nucleation can be avoided, and fully amorphous ribbons can be achieved. Comparison of the relevant time scales reveals that surface-controlled melt

  20. Improvement of long-term blindness caused by compression from inner-third sphenoid wing meningioma after optic canal decompression: An extremely rare case report

    PubMed Central

    Tamura, Ryota; Takahashi, Satoshi; Horikoshi, Tomo; Yoshida, Kazunari

    2016-01-01

    Background: There has been no previous case report of a patient whose visual acuity improved after long-term blindness caused by tumor invasion into the optic canal. Case Description: A 65-year-old Asian woman presented with a 6-month history of blindness caused by a meningioma located on the inner third of the sphenoid ridge. An operation was performed to prevent further tumor invasion into the cavernous sinus and contralateral optic nerve. During surgery, optic canal decompression was performed using an epidural approach. Subtotal removal of the tumor was achieved. Two days after the surgery, her left visual acuity recovered from blindness. Conclusion: Normally, long-term blindness caused by optic nerve compression by a brain tumor is regarded as irreversible, and even a surgical excision of the optic nerve is performed in some cases. However, because we experienced a case in which the patient recovered from long-term blindness after optic canal decompression, we believe that this surgical procedure should definitely be considered as an option. PMID:27413579

  1. Material dynamics at extreme pressures and strain rates

    SciTech Connect

    Remington, B A; Cavallo, R M; Edwards, M J; Ho, D D; Lasinski, B F; Lorenz, K T; Lorenzana, H E; McNaney, J M; Pollaine, S M; Yaakobi, B

    2004-08-25

    Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. [Re 2004] These extreme solid-state conditions can be accessed with either shock loading or with quasi-isentropic ramped pressure pulses being developed on the Omega laser. [Ed 2004] Velocity interferometer measurements establish the high strain rates. Constitutive models for solid-state strength under these conditions are tested by comparing 2D continuum simulations with experiments measuring perturbation growth due to the Rayleigh-Taylor instability in solid-state samples. Lattice compression, phase, and temperature are deduced from extended x-ray absorption fine structure (EXAFS) measurements, from which the shock-induced a-w phase transition in Ti is inferred to occur on sub-nanosecond time scales. [Ya 2004] Time resolved lattice response and phase can be inferred from dynamic x-ray diffraction measurements, where the elastic-plastic (1D-3D) lattice relaxation in shocked Cu is shown to occur promptly (< 1 ns). [Lo 2003] Subsequent large-scale MD simulations have elucidated the microscopic dynamics that underlie the 3D lattice relaxation. Deformation mechanisms are identified by examining the residual microstructure in recovered samples. [Re 2004] For example, the slip-twinning threshold in single-crystal Cu shocked along the [001] direction is shown to occur at shock strengths of 20-40 GPa, whereas the corresponding transition for Cu shocked along the [134] direction occurs at shock strengths of 40-60 GPa. We present highlights from our group's research in laser-based material science including our newest approach for achieving much higher pressures, P > 1000 GPa, in the solid state on the National Ignition Facility (NIF) laser.

  2. Material dynamics under extreme conditions of pressure and strain rate

    SciTech Connect

    Remington, B A; Allen, P; Bringa, E; Hawreliak, J; Ho, D; Lorenz, K T; Lorenzana, H; Meyers, M A; Pollaine, S W; Rosolankova, K; Sadik, B; Schneider, M S; Swift, D; Wark, J; Yaakobi, B

    2005-09-06

    Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. These extreme solid-state conditions can be accessed with either shock loading or with a quasi-isentropic ramped pressure drive. Velocity interferometer measurements establish the high pressure conditions. Constitutive models for solid-state strength under these conditions are tested by comparing 2D continuum simulations with experiments measuring perturbation growth due to the Rayleigh-Taylor instability in solid-state samples. Lattice compression, phase, and temperature are deduced from extended x-ray absorption fine structure (EXAFS) measurements, from which the shock-induced {alpha}-{omega} phase transition in Ti and the {alpha}-{var_epsilon} phase transition in Fe are inferred to occur on sub-nanosec time scales. Time resolved lattice response and phase can also be measured with dynamic x-ray diffraction measurements, where the elastic-plastic (1D-3D) lattice relaxation in shocked Cu is shown to occur promptly (< 1 ns). Subsequent large-scale molecular dynamics (MD) simulations elucidate the microscopic dynamics that underlie the 3D lattice relaxation. Deformation mechanisms are identified by examining the residual microstructure in recovered samples. The slip-twinning threshold in single-crystal Cu shocked along the [001] direction is shown to occur at shock strengths of {approx}20 GPa, whereas the corresponding transition for Cu shocked along the [134] direction occurs at higher shock strengths. This slip-twinning threshold also depends on the stacking fault energy (SFE), being lower for low SFE materials. Designs have been developed for achieving much higher pressures, P > 1000 GPa, in the solid state on the National Ignition Facility (NIF) laser.

  3. Endothelial dysfunction correlates with decompression bubbles in rats.

    PubMed

    Zhang, Kun; Wang, Dong; Jiang, Zhongxin; Ning, Xiaowei; Buzzacott, Peter; Xu, Weigang

    2016-01-01

    Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1α, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression-induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives. PMID:27615160

  4. A Start Toward Micronucleus-Based Decompression Models; Altitude Decompression

    NASA Technical Reports Server (NTRS)

    Van Liew, H. D.; Conkin, Johnny

    2007-01-01

    Do gaseous micronuclei trigger the formation of bubbles in decompression sickness (DCS)? Most previous instructions for DCS prevention have been oriented toward supersaturated gas in tissue. We are developing a mathematical model that is oriented toward the expected behavior of micronuclei. The issue is simplified in altitude decompressions because the aviator or astronaut is exposed only to decompression, whereas in diving there is a compression before the decompression. The model deals with four variables: duration of breathing of 100% oxygen before going to altitude (O2 prebreathing), altitude of the exposure, exposure duration, and rate of ascent. Assumptions: a) there is a population of micronuclei of various sizes having a range of characteristics, b) micronuclei are stable until they grow to a certain critical nucleation radius, c) it takes time for gas to diffuse in or out of micronuclei, and d) all other variables being equal, growth of micronuclei upon decompression is more rapid at high altitude because of the rarified gas in the micronuclei. To estimate parameters, we use a dataset of 4,756 men in altitude chambers exposed to various combinations of the model s variables. The model predicts occurrence of DCS symptoms quite well. It is notable that both the altitude chamber data and the model show little effect of O2 prebreathing until it lasts more than 60 minutes; this is in contrast to a conventional idea that the benefit of prebreathing is directly due to exponential washout of tissue nitrogen. The delay in response to O2 prebreathing can be interpreted as time required for outward diffusion of nitrogen; when the micronuclei become small enough, they are disabled, either by crushing or because they cannot expand to a critical nucleation size when the subject ascends to altitude.

  5. Extreme-ultraviolet ultrafast ARPES at high repetition rates

    NASA Astrophysics Data System (ADS)

    Buss, Jan; Wang, He; Xu, Yiming; Stoll, Sebastian; Zeng, Lingkun; Ulonska, Stefan; Denlinger, Jonathan; Hussain, Zahid; Jozwiak, Chris; Lanzara, Alessandra; Kaindl, Robert

    Time- and angle-resolved photoemission spectroscopy (trARPES) represents a powerful approach to resolve the electronic structure and quasiparticle dynamics in complex materials, yet is often limited in either momentum space (incident photon energy), probe sensitivity (pulse repetition rate), or energy resolution. We demonstrate a novel table-top trARPES setup that combines a bright 50-kHz source of narrowband, extreme ultraviolet (XUV) pulses at 22.3 eV with UHV photoemission instrumentation to sensitively access dynamics for a large momentum space. The output of a high-power Ti:sapphire amplifier is split to provide the XUV probe and intense photoexcitation (up to mJ/cm2) . A vacuum beamline delivers spectral and flux characterization, differential pumping, as well as XUV beam steering and toroidal refocusing onto the sample with high incident flux of 3x1011 ph/s. Photoemission studies are carried out in a customized UHV chamber equipped with a hemispherical analyzer (R4000), six-axis sample cryostat, and side chambers for sample loading, storage and preparation. An ARPES energy resolution down to 70 meV with the direct XUV output is demonstrated. We will discuss initial applications of this setup including Fermi surface mapping and trARPES of complex materials.

  6. Strain rate dependency of oceanic intraplate earthquake b-values at extremely low strain rates

    NASA Astrophysics Data System (ADS)

    Sasajima, Ryohei; Ito, Takeo

    2016-06-01

    We discovered a clear positive dependence of oceanic intraplate earthquake (OCEQ) b-values on the age of the oceanic lithosphere. OCEQ b-values in the youngest (<10 Ma) oceanic lithosphere are around 1.0, while those in middle to old (>20 Ma) oceanic lithosphere exceed 1.5, which is significantly higher than the average worldwide earthquake b-value (around 1.0). On the other hand, the b-value of intraplate earthquakes in the Ninety East-Sumatra orogen, where oceanic lithosphere has an anomalously higher strain rate compared with normal oceanic lithosphere, is 0.93, which is significantly lower than the OCEQ b-value (about 1.9) with the same age (50-110 Ma). Thus, the variation in b-values relates to the strain rate of the oceanic lithosphere and is not caused by a difference in thermal structure. We revealed a negative strain rate dependency of the b-value at extremely low strain rates (<2 × 10-10/year), which can clearly explain the above b-values. We propose that the OCEQ b-value depends strongly on strain rate (either directly or indirectly) at extremely low strain rates. The high OCEQ b-values (>1.5) in oceanic lithosphere >20 Ma old imply that future improvement in seismic observation will capture many smaller magnitude OCEQs, which will provide valuable information on the evolution of the oceanic lithosphere and the driving mechanism of plate tectonics.

  7. Heart rate regulation and extreme bradycardia in diving emperor penguins.

    PubMed

    Meir, Jessica U; Stockard, Torre K; Williams, Cassondra L; Ponganis, Katherine V; Ponganis, Paul J

    2008-04-01

    To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly extremely low values: f(H) during the last 5 mins of an 18 min dive was 6 beats min(-1). Dive f(H) and minimum instantaneous f(H) during dives declined significantly with increasing dive duration. Dive f(H) was independent of swim stroke frequency. This suggests that progressive bradycardia and peripheral vasoconstriction (including isolation of muscle) are primary determinants of blood oxygen depletion in diving emperor penguins. Maximum instantaneous surface interval f(H) in this study is the highest ever recorded for emperor penguins (256 beats min(-1)), equivalent to f(H) at V(O(2)) max., presumably facilitating oxygen loading and post-dive metabolism. The classic Scholander-Irving dive response in these emperor penguins contrasts with the absence of true bradycardia in diving ducks, cormorants, and other penguin species. PMID:18375841

  8. Endoscopic Intermetatarsal Ligament Decompression.

    PubMed

    Lui, Tun Hing

    2015-12-01

    Morton neuroma is an entrapment of the intermetatarsal nerve by the deep intermetatarsal ligament. It is usually treated conservatively. Surgery is considered if there is recalcitrant pain that is resistant to conservative treatment. The surgical options include resection of the neuroma or decompression of the involved nerve. Decompression of the nerve by release of the intermetatarsal ligament can be performed by either an open or minimally invasive approach. We describe 2-portal endoscopic decompression of the intermetatarsal nerve. The ligament is released by a retrograde knife through the toe-web portal under arthroscopic guidance through the plantar portal. PMID:27284515

  9. Estimating rates of decompression from textures of erupted ash particles produced by 1999-2006 eruptions of Tungurahua volcano, Ecuador

    USGS Publications Warehouse

    Wright, Heather M.N.; Cashman, Katharine V.; Mothes, Patricia A.; Hall, Minard L.; Ruiz, Andrés Gorki; Le Pennec, Jean-Luc

    2012-01-01

    Persistent low- to moderate-level eruptive activity of andesitic volcanoes is difficult to monitor because small changes in magma supply rates may cause abrupt transitions in eruptive style. As direct measurement of magma supply is not possible, robust techniques for indirect measurements must be developed. Here we demonstrate that crystal textures of ash particles from 1999 to 2006 Vulcanian and Strombolian eruptions of Tungurahua volcano, Ecuador, provide quantitative information about the dynamics of magma ascent and eruption that is difficult to obtain from other monitoring approaches. We show that the crystallinity of erupted ash particles is controlled by the magma supply rate (MSR); ash erupted during periods of high magma supply is substantially less crystalline than during periods of low magma supply. This correlation is most easily explained by efficient degassing at very low pressures (<<50 MPa) and degassing-driven crystallization controlled by the time available prior to eruption. Our data also suggest that the observed transition from intermittent Vulcanian explosions at low MSR to more continuous periods of Strombolian eruptions and lava fountains at high MSR can be explained by the rise of bubbles through (Strombolian) or trapping of bubbles beneath (Vulcanian) vent-capping, variably viscous (and crystalline) magma.

  10. Decompressive craniectomy: technical note.

    PubMed

    Quinn, T M; Taylor, J J; Magarik, J A; Vought, E; Kindy, M S; Ellegala, D B

    2011-04-01

    Decompressive craniectomy is a neurosurgical technique in which a portion of the skull is removed to reduce intracranial pressure. The rationale for this procedure is based on the Monro-Kellie Doctrine; expanding the physical space confining edematous brain tissue after traumatic brain injury will reduce intracranial pressure. There is significant debate over the efficacy of decompressive craniectomy despite its sound rationale and historical significance. Considerable variation in the employment of decompressive craniectomy, particularly for secondary brain injury, explains the inconsistent results and mixed opinions of this potentially valuable technique. One way to address these concerns is to establish a consistent methodology for performing decompressive craniectomies. The purpose of this paper is to begin accomplishing this goal and to emphasize the critical points of the hemicraniectomy and bicoronal (Kjellberg type) craniectomy. PMID:20637010

  11. [Decompression of deep divers].

    PubMed

    Gardette, B

    1989-08-01

    For industrial saturation dives over 50 m, Heliox (He-O2) is now used routinely as respiratory gas mix. The decompression after such dives has been investigated thoroughly as well on the animal (minipig, monkeys) as on humans. Results show that for a given ascending speed, the number of bubbles detectable by the Doppler method in the bloodstream rises according to the maximal depth. The incidence of decompression accidents follows the same trend. This finding prompted us to adopt since 1979 slower decompression speeds. Moreover we modified the ascension profile, using henceforth a linear decompression in maintaining a constant speed for a given partial oxygen pressure. For our research program Hydra, we replaced in part Helium by Hydrogen in the respiratory gas mix. We were thus able to do the first hydrogen saturation decompression between 450 and 200 meters, during our Hydra V (1985) experiment. During our following diving research program Hydra VI (1986), 8 divers were decompressed under Hydreliox (H2-He-O2) mix from 500 to 300 m by eliminating hydrogen by chemical means. We used for this purpose a dehydrogenation apparatus developed by our engineering team. These decompressions took place without any difficulty and only a low number of bubbles detected. It is therefore possible to use decompression speeds for hydrogen and helium which are very similar. A confirmatory experiment on mice, where we exposed them to a 2000 m depth dive under Hydreliox (H2-He-O2), gave good results. This gives us the possibility, to perform gas exchange studies on small animals and to extrapolate the results to humans. PMID:2799362

  12. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... rate not greater than 5 pounds per minute. Further reduction in pressure will take place during stage 2... minute. Decompression Table No. 1 indicates in the body of the table the total decompression time in... rate of 5 pounds per minute. Elapsed time stage 1: 16/5 3 Stage 2 (final stage): Reduce pressure at...

  13. Spall Response of Tantalum at Extreme Strain-Rates

    NASA Astrophysics Data System (ADS)

    Hahn, Eric; Germann, Tim; Meyers, Marc

    Strain-rate and microstructure play a significant role in the ultimate mechanical response of materials. Using non-equilibrium molecular dynamics simulations, we characterize the ductile tensile failure of single and nanocrystalline tantalum over multiple orders of magnitude of strain-rate. This comparison is extended to over nine orders of magnitude including experimental results from resent laser shock campaigns. Spall strength primarily follows a power law dependence with strain-rate over this extensive range. In all cases, voids nucleate heterogeneously at pre-existing defects. Predictions based on traditional theory suggest that, as strain-rate increases, tensile strength should increase. Alternatively, as grain size decreases, tensile strength may decrease due to an increased propensity to fail at a growing volume fraction of grain boundaries. Strain-rate and grain size dictate void nucleation sites by changing the type and density of available defects: vacancies, dislocations, twins, and grain boundaries.

  14. Cutaneous decompression sickness.

    PubMed

    Tasios, Konstantinos; Sidiras, Georgios Gr; Kalentzos, Vasileios; Pyrpasopoulou, Athina

    2014-03-01

    A probable case of decompression illness with associated cutis marmorata is presented, which regressed over a few hours with oxygen breathing and after intravenous methylprednisolone and fluid resuscitation without recompression. He was eventually transferred for hyperbaric treatment some 10 hours post dive. Cutaneous decompression illness is not associated with high mortality per se, but prompt and accurate recognition is warranted, as it may represent a prodromal feature of potentially life-threatening complications. However, in this case, as differential diagnosis, an allergic reaction remains possible. PMID:24687485

  15. Materials Science under Extreme Conditions of Pressure and Strain Rate

    SciTech Connect

    Remington, B A; Bazan, G; Bringa, E; Caturla, M; Edwards, M J; Glendinning, S G; Kad, B; Kalantar, D H; Kumar, M; Lasinski, B F; Lorenz, K T; McNaney, J; Meyerhofer, D; Meyers, M A; Pollaine, S M; Reisman, D B; Rowley, D; Schneider, M; Stolken, J; Wark, J; Yaakobi, B

    2003-03-27

    Solid state dynamics experiments at very high pressures (P >> 10 GPa) and strain rates ({var_epsilon} >> 10{sup 5} s{sup -1}) have been demonstrated on high energy laser facilities, albeit over brief intervals of time and small spatial scales. We have developed two methods for driving samples to high pressures (10-100 GPa) at high strain rate (10{sup 6}-10{sup 8} s{sup -1}) in the solid state. One method uses a shockless compression technique, and the other uses multiple staged shocks. These drives are calibrated with VISAR measurements of the resulting compression wave. Deformation mechanisms are inferred under these conditions by characterizing recovered samples. Material strength at high pressures and strain rates is deduced by measuring the reduced growth of material perturbations at a hydrodynamically unstable interface. Microscopic lattice response is determined by time-resolved Bragg diffraction and x-ray absorption spectroscopy (EXAFS). Large-scale simulations, both at the continuum level using constitutive models and at the lattice level using molecular dynamics simulation, are used to interpret these integral experiments. We will review our progress in this new area of laser-based materials science research, then present a vision for carrying these solid-state experiments to much higher pressures, P > 1000 GPa, on the National Ignition Facility (NIF) laser facility.

  16. Paradoxical Herniation following Decompressive Craniectomy in the Subacute Setting

    PubMed Central

    Espinosa, Jose

    2016-01-01

    Decompressive craniectomy is reserved for extreme cases of intracranial hypertension. An uncommon complication known as paradoxical herniation has been documented within weeks to months following surgery. Here we present a unique case within days of surgery. Since standard medical treatment for intracranial hypertension will exacerbate paradoxical herniation, any abrupt neurological changes following decompressive craniectomy should be carefully investigated. Immediate treatment for paradoxical herniation is placement of the patient in the supine position with adequate hydration. Cranioplasty is the ultimate treatment option. PMID:27446619

  17. Paradoxical Herniation following Decompressive Craniectomy in the Subacute Setting.

    PubMed

    Michael, Alex P; Espinosa, Jose

    2016-01-01

    Decompressive craniectomy is reserved for extreme cases of intracranial hypertension. An uncommon complication known as paradoxical herniation has been documented within weeks to months following surgery. Here we present a unique case within days of surgery. Since standard medical treatment for intracranial hypertension will exacerbate paradoxical herniation, any abrupt neurological changes following decompressive craniectomy should be carefully investigated. Immediate treatment for paradoxical herniation is placement of the patient in the supine position with adequate hydration. Cranioplasty is the ultimate treatment option. PMID:27446619

  18. Delayed facial nerve decompression for Bell's palsy.

    PubMed

    Kim, Sang Hoon; Jung, Junyang; Lee, Jong Ha; Byun, Jae Yong; Park, Moon Suh; Yeo, Seung Geun

    2016-07-01

    Incomplete recovery of facial motor function continues to be long-term sequelae in some patients with Bell's palsy. The purpose of this study was to investigate the efficacy of transmastoid facial nerve decompression after steroid and antiviral treatment in patients with late stage Bell's palsy. Twelve patients underwent surgical decompression for Bell's palsy 21-70 days after onset, whereas 22 patients were followed up after steroid and antiviral therapy without decompression. Surgical criteria included greater than 90 % degeneration on electroneuronography and no voluntary electromyography potentials. This study was a retrospective study of electrodiagnostic data and medical chart review between 2006 and 2013. Recovery from facial palsy was assessed using the House-Brackmann grading system. Final recovery rate did not differ significantly in the two groups; however, all patients in the decompression group recovered to at least House-Brackmann grade III at final follow-up. Although postoperative hearing threshold was increased in both groups, there was no significant between group difference in hearing threshold. Transmastoid decompression of the facial nerve in patients with severe late stage Bell's palsy at risk for a poor facial nerve outcome reduced severe complications of facial palsy with minimal morbidity. PMID:26319412

  19. Cardiovascular Pressures with Venous Gas Embolism and Decompression

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Robinson, R.; Sutton, T.; Kemper, G. B.

    1995-01-01

    Venous gas embolism (VGE) is reported with decompression to a decreased ambient pressure. With severe decompression, or in cases where an intracardiac septal defect (patent foramen ovale) exists, the venous bubbles can become arterialized and cause neurological decompression illness. Incidence rates of patent foramen ovale in the general population range from 25-34% and yet aviators, astronauts, and deepsea divers who have decompression-induced venous bubbles do not demonstrate neurological symptoms at these high rates. This apparent disparity may be attributable to the normal pressure gradient across the atria of the heart that must be reversed for there to be flow potency. We evaluated the effects of: venous gas embolism (0.025, 0.05 and 0.15 ml/ kg min for 180 min.) hyperbaric decompression; and hypobaric decompression on the pressure gradient across the left and right atria in anesthetized dogs with intact atrial septa. Left ventricular end-diastolic pressure was used as a measure of left atrial pressure. In a total of 92 experimental evaluations in 22 dogs, there were no reported reversals in the mean pressure gradient across the atria; a total of 3 transient reversals occurred during the peak pressure gradient changes. The reasons that decompression-induced venous bubbles do not consistently cause serious symptoms of decompression illness may be that the amount of venous gas does not always cause sufficient pressure reversal across a patent foramen ovale to cause arterialization of the venous bubbles.

  20. Diving behaviour and decompression sickness among Galapagos underwater harvesters.

    PubMed

    Westin, A A; Asvall, J; Idrovo, G; Denoble, P; Brubakk, A O

    2005-01-01

    Diving conditions, dive profiles, vascular bubbles, and symptoms of decompression sickness (DCS) in a group of Galapagos commercial divers are described. They harvest sea cucumbers from small boats with surface supplied air (hookah). Dive profiles for 12 divers were recorded using dive loggers, and bubble formation was measured in the pulmonary artery. DCS symptoms were assessed by interview. A total of 380 immersions were recorded over a nine day period. The divers did on average 6.3 immersions per day, in a yo-yo pattern. Mean overall depth was 34.5 FSW. Maximum recorded depth was 107 FSW. Average bottom time per day per diver was 175 minutes. 82 % of all ascents exceeded the recommended maximum ascent rate of 30 FSW/ min. High bubble grades were observed on six occasions, but the test was unreliable. Muscle and joint pain was reported on five occasions, in three different divers. Symptoms were typically managed by analgesics, in-water recompression or not at all. The divers were extremely reluctant to seek professional help for DCS symptoms, mostly due to the high costs of treatment. We conclude that the fishermen dive beyond standard no-decompression limits, and that DCS symptoms are common. PMID:16119309

  1. Percutaneous laser disc decompression.

    PubMed

    Choy, D S

    1995-06-01

    Herniated disc disease has an incidence of 1.7% in the U.S. Heretofore, open operative procedures were the rule for this condition when conservative measures were ineffective. Choy and Ascher introduced this new technique in February 1986 using a Nd:YAG laser introduced into the disc through an optical fiber in a needle. Percutaneous laser disc decompression is based on the principle that in an enclosed hydraulic space, such as an intact disc, a small reduction in volume is associated with a disproportionate fall in pressure. In the disc, this partial vacuum causes the herniated portion to move away from the nerve root back toward the center of the disc. This technique has been taught worldwide and is being performed in most of Europe, Japan, the United States, and Korea. In this special issue devoted to percutaneous laser disc decompression (PLDD), we will set forth the basic science of PLDD, patient selection, use of the holmium:YAG, and the Nd:YAG lasers, operative technique, and results. PMID:10150634

  2. Extreme Lightning Flash Rates as an Early Indicator of Severe Storms

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Arnold, James E. (Technical Monitor)

    2002-01-01

    Extreme lightning flash rates are proving to be an early indicator of intensifying storms capable of producing tornadoes, damaging winds and hail. Most of this lightning is in the cloud, where the naked eye can not see it. Recent global observations of thunderstorms from space indicate that giant electrical storms (supercells and convective complexes) with flash rates on the order of 1 flash per second are most common over the land masses of the America sub-tropics and equatorial Congo Basin. Within the United States, the average tornado warning lead time on a national basis is about 11 min. The real-time observation of extreme flash rates and the rapid increase in the in-cloud flash rate, signalling the intensification of the storm updraft, may provide as much as a 50% increase in severe storm warning lead time.

  3. Decompression for management of keratocystic odontogenic tumor in the mandible.

    PubMed

    Morais de Melo, Willian; Pereira-Santos, Darklilson; Sonoda, Celso Koogi; Hochuli-Vieira, Eduardo

    2012-11-01

    Keratocystic odontogenic tumor (KCOT) is a benign intraosseous neoplasm of odontogenic origin with high recurrence rate. To date, various conservative or aggressive management strategies have been suggested as a method of treatment. Decompression is a conservative method that has been used in the treatment of large odontogenic cysts. The present paper reports a case of KCOT located in the mandible and discusses the importance of its management using conservative methods. The authors present a case of a 38-year-old patient with a KCOT located in the right mandibular angle and ascending ramus, which was treated by decompression followed by enucleation and curettage. The lesion did not recur during a follow-up period of 3 years after surgery. Preserving important structures of the bone and soft tissue decompression is a method with low morbidity. In addition, according to the literature, decompression has a success rate at least as high as the one of most aggressive treatments. PMID:23172507

  4. Validation of diving decompression tables.

    PubMed

    Kłos, Ryszard; Nishi, Ron; Olszański, Roman

    2002-01-01

    Research on the validation of decompression tables is one of the common subject areas of the co-operation undertaken between the Defence and Civil Institute of Environmental Medicine, Toronto, Canada, and The Naval Academy of Gdynia, Poland. For several years now, a systematic survey of diving technologies has been conducted among the target projects financed by the Polish State Committee for Scientific Research and the Polish Navy. Among the most important problems discussed have been various aspects of decompression safety. The present paper shows a study to standardise and unify validation procedures for decompression in the Polish Navy. PMID:12608591

  5. Microvascular decompression for intractable singultus.

    PubMed

    Saito, Atsushi; Hatayama, Toru; Kon, Hiroyuki; Nakamura, Taigen; Sasaki, Tatsuya

    2016-10-01

    Intractable singultus due to cerebrovascular disease is very rare. We report a case of intractable singultus that improved after microvascular decompression and present a literature review. The patient was a 58-year-old man with a 30-year history of persistent singultus. Its frequency and duration gradually increased and it was resistant to multiple medical treatments. Microvascular decompression to relieve pressure on the anterolateral surface of the lower medulla oblongata from the vertebral artery resulted in the resolution of singultus. Patients with intractable idiopathic singultus who fail to respond to medical therapy need to be considered for the evaluation of cerebrovascular diseases and microvascular decompression. PMID:27335312

  6. Soccer-Specific Warm-Up and Lower Extremity Injury Rates in Collegiate Male Soccer Players

    PubMed Central

    Grooms, Dustin R.; Palmer, Thomas; Onate, James A.; Myer, Gregory D.; Grindstaff, Terry

    2013-01-01

    Context: A number of comprehensive injury-prevention programs have demonstrated injury risk-reduction effects but have had limited adoption across athletic settings. This may be due to program noncompliance, minimal exercise supervision, lack of exercise progression, and sport specificity. A soccer-specific program described as the F-MARC 11+ was developed by an expert group in association with the Federation Internationale de Football Association (FIFA) Medical Assessment and Research Centre (F-MARC) to require minimal equipment and implementation as part of regular soccer training. The F-MARC 11+ has been shown to reduce injury risk in youth female soccer players but has not been evaluated in an American male collegiate population. Objective: To investigate the effects of a soccer-specific warm-up program (F-MARC 11+) on lower extremity injury incidence in male collegiate soccer players. Design: Cohort study. Setting: One American collegiate soccer team followed for 2 seasons. Patients or Other Participants: Forty-one male collegiate athletes aged 18–25 years. Intervention(s): The F-MARC 11+ program is a comprehensive warm-up program targeting muscular strength, body kinesthetic awareness, and neuromuscular control during static and dynamic movements. Training sessions and program progression were monitored by a certified athletic trainer. Main Outcome Measure(s): Lower extremity injury risk and time lost to lower extremity injury. Results: The injury rate in the referent season was 8.1 injuries per 1000 exposures with 291 days lost and 2.2 injuries per 1000 exposures and 52 days lost in the intervention season. The intervention season had reductions in the relative risk (RR) of lower extremity injury of 72% (RR = 0.28, 95% confidence interval = 0.09, 0.85) and time lost to lower extremity injury (P < .01). Conclusions: This F-MARC 11+ program reduced overall risk and severity of lower extremity injury compared with controls in collegiate-aged male soccer

  7. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... requirements of § 197.330(a) (3), (4), and (5) is used; (i) Have a minimum pressurization rate of 2 ATA per minute to 60 fsw and at least 1 ATA per minute thereafter; (j) Have a decompression rate of 1 ATA per... capability to supply breathing mixtures at the maximum rate required by each occupant doing heavy work;...

  8. Comparison of clinical outcomes in decompression and fusion versus decompression only in patients with ossification of the posterior longitudinal ligament: a meta-analysis.

    PubMed

    Mehdi, Syed K; Alentado, Vincent J; Lee, Bryan S; Mroz, Thomas E; Benzel, Edward C; Steinmetz, Michael P

    2016-06-01

    OBJECTIVE Ossification of the posterior longitudinal ligament (OPLL) is a pathological calcification or ossification of the PLL, predominantly occurring in the cervical spine. Although surgery is often necessary for patients with symptomatic neurological deterioration, there remains controversy with regard to the optimal surgical treatment. In this systematic review and meta-analysis, the authors identified differences in complications and outcomes after anterior or posterior decompression and fusion versus after decompression alone for the treatment of cervical myelopathy due to OPLL. METHODS A MEDLINE, SCOPUS, and Web of Science search was performed for studies reporting complications and outcomes after decompression and fusion or after decompression alone for patients with OPLL. A meta-analysis was performed to calculate effect summary mean values, 95% CIs, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 2630 retrieved articles, 32 met the inclusion criteria. There was no statistically significant difference in the incidence of excellent and good outcomes and of fair and poor outcomes between the decompression and fusion and the decompression-only cohorts. However, the decompression and fusion cohort had a statistically significantly higher recovery rate (63.2% vs 53.9%; p < 0.0001), a higher final Japanese Orthopaedic Association score (14.0 vs 13.5; p < 0.0001), and a lower incidence of OPLL progression (< 1% vs 6.3%; p < 0.0001) compared with the decompression-only cohort. There was no statistically significant difference in the incidence of complications between the 2 cohorts. CONCLUSIONS This study represents the only comprehensive review of outcomes and complications after decompression and fusion or after decompression alone for OPLL across a heterogeneous group of surgeons and patients. Based on these results, decompression and fusion is a superior surgical technique compared with posterior

  9. Degassing of H2O in a phonolitic melt: A closer look at decompression experiments

    NASA Astrophysics Data System (ADS)

    Marxer, Holger; Bellucci, Philipp; Nowak, Marcus

    2015-05-01

    Melt degassing during magma ascent is controlled by the decompression rate and can be simulated in decompression experiments. H2O-bearing phonolitic melts were decompressed at a super-liquidus T of 1323 K in an internally heated argon pressure vessel, applying continuous decompression (CD) as well as to date commonly used step-wise decompression (SD) techniques to investigate the effect of decompression method on melt degassing. The hydrous melts were decompressed from 200 MPa at nominal decompression rates of 0.0028-1.7 MPa·s- 1. At final pressure (Pfinal), the samples were quenched rapidly at isobaric conditions with ~ 150 K·s- 1. The bubbles in the quenched samples are often deformed and dented. Flow textures in the glass indicate melt transport at high viscosity. We suggest that this observation is due to bubble shrinkage during quench. This general problem was mostly overlooked in the interpretation of experimentally degassed samples to date. Bubble shrinkage due to decreasing molar volume (Vm) of the exsolved H2O in the bubbles occurs during isobaric rapid quench until the melt is too viscous too relax. The decrease of Vm(H2O) during cooling at Pfinal of the experiments results in a decrease of the bubble volume by a shrinking factor Bs: At nominal decompression rates > 0.17 MPa·s- 1 and a Pfinal of 75 MPa, the decompression method has only minor influence on melt degassing. SD and CD result in high bubble number densities of 104-105 mm- 3. Fast P drop leads to immediate supersaturation with H2O in the melt. At such high nominal decompression rates, the diffusional transport of H2O is limited and therefore bubble nucleation is the predominant degassing process. The residual H2O contents in the melts decompressed to 75 MPa increase with nominal decompression rate. After homogeneous nucleation is triggered, CD rates ≤ 0.024 MPa·s- 1 facilitate continuous reduction of the supersaturation by H2O diffusion into previously nucleated bubbles. Bubble number

  10. Extreme stress gradient effects on microstructural fatigue crack propagation rates in Ni microbeams

    SciTech Connect

    Sadeghi-Tohidi, F.; Pierron, O. N.

    2015-05-18

    The fatigue crack propagation behavior of microstructurally small cracks growing under extreme stress gradients was investigated in Ni microbeams under fully reversed cyclic loading. A technique to calculate the crack growth rates in microbeams with two different normalized stress gradients (17% and 50% μm{sup −1}) is developed and validated. Decreasing crack propagation rates are observed over the first 2 μm, and the rates are more than 1 order of magnitude slower for the devices with 50% μm{sup −1} stress gradients. This fundamental knowledge is critical to predict the fatigue reliability of advanced metallic microcomponents under bending such as in microelectromechanical systems or flexible/stretchable electronics.

  11. Rule based artificial intelligence expert system for determination of upper extremity impairment rating.

    PubMed

    Lim, I; Walkup, R K; Vannier, M W

    1993-04-01

    Quantitative evaluation of upper extremity impairment, a percentage rating most often determined using a rule based procedure, has been implemented on a personal computer using an artificial intelligence, rule-based expert system (AI system). In this study, the rules given in Chapter 3 of the AMA Guides to the Evaluation of Permanent Impairment (Third Edition) were used to develop such an AI system for the Apple Macintosh. The program applies the rules from the Guides in a consistent and systematic fashion. It is faster and less error-prone than the manual method, and the results have a higher degree of precision, since intermediate values are not truncated. PMID:8334872

  12. Dynamic Heating and Decompression Experiments on Dacite and Rhyolite Magmas

    NASA Astrophysics Data System (ADS)

    Andrews, B. J.; Waters, L.; Grocke, S. B.

    2015-12-01

    Mineral reaction rims, zoned crystals, and myriad growth or dissolution textures provide evidence for changes in magma pressure, temperature, or composition. Quantifying the magnitudes, timescales and length scales of those variations is a fundamental challenge of volcanology and igneous petrology; experiments provide quantitative insights into how magmas react to changes in pressure and temperature that can be used to address that challenge. We use single-step and dynamic experiments conducted in cold seal pressure vessels to study the responses of dacite and rhyolite magmas to heating and decompression events. During single-step decompression (or heating) experiments, conditions are changed nearly instantaneously from the initial to final state in one step, or several smaller steps, whereas "dynamic experiments" have continuous variation in pressure and/or temperature. These two types of experiments yield useful and complementary information describing crystal nucleation, growth, and reaction rates in response to changing (as opposed to steady state) conditions. Here we discuss isothermal decompression experiments that show substantial path-dependence for runs with equivalent time-averaged decompression rates as slow as 0.27 MPa/h for >500 h. Continuous decompression experiments often contain fewer but larger plagioclase crystals than are present in single-step runs, and those new crystals often show complex growth textures. Our results suggest that even slow changes in storage conditions can disrupt melt structure and greatly retard nucleation provided the changes are steady. We hypothesize that if the decompression path remains steady and continuous (absent a stall on and/or rapid decompression), the magma can remain in a growth-dominated regime even though it is far from equilibrium.

  13. Optimization of TRMM 2A25 Extreme Rainfall Rate and Probability

    NASA Astrophysics Data System (ADS)

    Manz, Bastian; Buytaert, Wouter; Onof, Christian

    2014-05-01

    With the launch of the Global Precipitation Measurement (GPM) mission imminent, the Tropical Rainfall Measurement Mission (TRMM) Precipitation Radar (TPR) still represents one of the most accurate satellite-based on-land rainfall measurements. However, as a low-orbital satellite (swath width 247km) with a comparatively low temporal sampling frequency, there is a high likelihood that TPR does not observe individual storm events, most notably localized tropical convective storms. Furthermore, the TPR product 2A25 standard radar reflectivity- rainfall rate (Z-R) relationship is optimized for moderate precipitation rates, given their more frequent occurrence, which affects estimation of high-intensity events. In this study two methods are presented for optimization of extreme rainfall intensity and probability in TRMM 2A25. Firstly, the TPR reflectivity-rainfall relationship (Z-R relationship) was re-calibrated for 143 gauge locations across Peru based on hourly gauge measurements from 2005-2013. Various rainfall thresholds were defined to focus Z-R optimization on extreme precipitation rates. In each case the updated set of parameters were applied to the remaining TPR observations using an interpolation approach to obtain a spatially-continuous improved dataset for Peru. Secondly, the extreme precipitation probability statistics of both the original and updated 2A25 datasets were assessed. For this purpose General Pareto Distributions (GPD) were fitted to Partial Duration Series (Peaks-over-Threshold) of the original and updated 2A25 product at the 143 gauge locations as well as to the gauge records themselves. The 2A25 statistics were perturbed to match the GPD parameters and distributions of the gauges. The correction factors were applied to the entire 2A25 dataset to obtain distributions across the region. Performance of the Z-R re-calibration and extreme precipitation probability optimization was evaluated using a split-sample cross-validation whereby 90% of the

  14. Variation and Trends in Lower Extremity Amputation Rates in Los Angeles County Hospitals 2000-2010.

    PubMed

    Jindeel, Ayad; Gessert, Charles; Johnson, Brian P

    2016-09-01

    Lower extremity amputation (LEA) is a preventable complication of diabetes and peripheral vascular disease. Hospital-related factors associated with higher LEA are low hospital LEA revascularization volume, rural setting, and nonteaching status. In this study, we describe LEA rates in health care systems and hospitals in Los Angeles County from 2000 to 2010. Data on hospital discharges in Los Angeles County from 2000 to 2010 were obtained from the California Office of Statewide Health Planning and Development. LEA rates were adjusted for clinical and demographic variables including age, sex, race, source of health care payment, diabetes, and peripheral vascular disease. Adjusted LEA rates over the study period were analyzed by category of hospital (municipal, nonprofit/non-Kaiser, Kaiser, and private), and for changes in rates in each hospital over the study period. Over the 11-year study period the LEA rates increased for municipal hospitals, while decreasing for the other 3 categories of hospitals. Among the 84 hospitals included in the final analysis, 41 hospitals had higher than average relative risk for LEA in 2007-2010. Among these hospitals 12 had higher than average decline in LEA rate between 2000-2003 and 2007-2010. The other 29 hospitals had not lowered the LEA rate as much as the whole County over the study period. After adjusting for demographic and clinical variables, the relative risk for LEA among hospitals varied by 7.5-fold. Significant variability was found both within each of the 4 types of hospitals, and between the 4 types. Hospitals also varied in the degree that they lowered their LEA rates. This study demonstrated that health care systems and hospitals are associated with significant disparity in LEA rates among socioeconomic groups and geographical regions. PMID:27335119

  15. Multifractal comparison of the extremes of rain rates and integrated vapour content

    NASA Astrophysics Data System (ADS)

    Gires, Auguste; Ni, Vincent; Bosser, Pierre; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2015-04-01

    Rainfall extremes are studied through the analyse of three related fields measured with the help of co-located devices installed in the roof of the Ecole des Ponts ParisTech building: (i) Integrated Water Vapour (IWV); it corresponds the amount of water vapour present in the vertical columns between a GPS ground receiver and corresponding satellites. It is estimated from the time shift between the expected duration the signal needs to reach the receiver (the two positions are known) and the actual one (ii) Rain rate measured by three optical disdrometers of two different types (Campbell Scientific PWS100 and OTT Parsivel2) (iii) Relative humidity measured by a dedicated sensor First the correlations between these quantities during significant events is analysed. It appears that although IWV tends to decrease (vapour condense to form drops that fall) and relative humidity to increase during a rainfall event, it turns out difficult to quantitatively characterize this link. It is possibly due to the fact that the scale gap between a punctual measure for the rain rate and an average over a few km height column for the IWV is too large. Finally the scaling features of these three fields are investigated with the help of the Universal Multifractal framework which has been extensively used to analyse and simulate geophysical fields extremely variable over wide ranges of scales. Only three parameters are used to characterize variability across scales: C1 the mean intermittency, alpha the multifractality index and H the non-conservative exponent. Retrieved features are compared and the notion of maximum observable singularity is used to quantify the extremes of the various fields. Authors acknowledge the financial support of the Interreg IV NEW RainGain project (www.raingain.eu) and the chair "hydrology for resilient cities" sponsored by Véolia, and the Climate-KIC Blue Green Dream project (bgd.org.uk/).

  16. Decompressive craniectomy in neurocritical care.

    PubMed

    Wang, Jia-Wei; Li, Jin-Ping; Song, Ying-Lun; Tan, Ke; Wang, Yu; Li, Tao; Guo, Peng; Li, Xiong; Wang, Yan; Zhao, Qi-Huang

    2016-05-01

    Recently, several randomized controlled trials (RCT) investigating the effectiveness of decompressive craniectomy in the context of neurocritical illnesses have been completed. Thus, a meta-analysis to update the current evidence regarding the effects of decompressive craniectomy is necessary. We searched PUBMED, EMBASE and the Cochrane Central Register of Controlled Trials. Other sources, including internet-based clinical trial registries and grey literature, were also searched. After searching the literature, two investigators independently performed literature screening, assessing the quality of the included trials and extracting the data. The outcome measures included the composite outcome of death or dependence and the risk of death. Ten RCT were included: seven RCT were on malignant middle cerebral artery infarction (MCAI) and three were on severe traumatic brain injury (TBI). Decompressive craniectomy significantly reduced the risk of death for patients suffering malignant MCAI (risk ratio [RR] 0.46, 95% confidence interval [CI]: 0.36-0.59, P<0.00001) in comparison with no reduction in the risk of death for patients with severe TBI (RR: 0.83, 95% CI: 0.48-1.42, P=0.49). However, there was no significant difference in the composite risk of death or dependence at the final follow-up between the decompressive craniectomy group and the conservative treatment group for either malignant MCAI or severe TBI. The present meta-analysis indicates that decompressive craniectomy can significantly reduce the risk of death for patients with malignant MCAI, although no evidence demonstrates that decompressive craniectomy is associated with a reduced risk of death or dependence for TBI patients. PMID:26879572

  17. Weak Line Quasars at High Redshift: Extremely High Accretion Rate Sources?

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad

    2011-10-01

    The Sloan Digital Sky Survey has recently discovered a remarkable group of ~80 quasars at z=2.2-5.9 with extremely weak emission lines in their rest-frame UV spectra. We propose to extend our XMM-Newton observations of such sources and obtain imaging spectroscopy of four quasars of this class with a total exposure time of 165 ks, providing ~1000 photons per source. This will enable an accurate measurement of the hard-X-ray photon index required for a robust determination of the accretion rate in each source. Steep spectral slopes will indicate that high accretion rates may be responsible for the intrinsic weakness of the UV emission lines. The proposed observations will lead to new insights about the accretion process and broad emission line formation in all active galactic nuclei.

  18. Weak Line Quasars at High Redshift: Extremely High Accretion Rate Sources?

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad

    2010-10-01

    The Sloan Digital Sky Survey has recently discovered a remarkable group of ~80 quasars at z=2.2-5.9 with extremely weak emission lines in their rest-frame UV spectra. We propose to extend our XMM-Newton observations of such sources and obtain imaging spectroscopy of four quasars of this class with a total exposure time of 165 ks, providing ~1000 photons per source. This will enable an accurate measurement of the hard-X-ray photon index required for a robust determination of the accretion rate in each source. Steep spectral slopes will indicate that high accretion rates may be responsible for the intrinsic weakness of the UV emission lines. The proposed observations will lead to new insights about the accretion process and broad emission line formation in all active galactic nuclei.

  19. Weak Line Quasars at High Redshift: Extremely High Accretion Rate Sources?

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad

    2013-10-01

    The Sloan Digital Sky Survey has discovered a remarkable group of ~100 quasars with extremely weak emission lines in their rest-frame optical-UV spectra. We propose to extend our XMM-Newton observations of such sources and obtain imaging spectroscopy of six quasars of this class with a total exposure time of 128 ks, providing ~1000 photons per source. This will enable an accurate measurement of the hard-X-ray photon index required for a robust determination of the accretion rate in each source. Steep spectral slopes will indicate that high accretion rates may be responsible for the intrinsic weakness of the optical-UV emission lines. The proposed observations will lead to new insights about the accretion process and broad emission line formation in all active galactic nuclei.

  20. Recognising and managing decompression illness.

    PubMed

    Caton-Richards, Michelle

    2013-11-01

    Seen primarily in scuba divers who have breathed compressed air, decompression illness is a rare but potentially fatal condition. Prompt recognition and treatment of the illness, and urgent referral of patients to hyperbaric chambers, can mean the difference between full recovery and paralysis or death. This article describes decompression illness and how to recognise it, and discusses the treatment that patients require for the best chance of recovery with no adverse effects. It also includes a case study of a patient who developed this condition after a dive. PMID:24219686

  1. Revision Rate and Risk Factors After Lower Extremity Amputation in Diabetic or Dysvascular Patients.

    PubMed

    Wanivenhaus, Florian; Mauler, Flavien; Stelzer, Teresa; Tschopp, Alois; Böni, Thomas; Berli, Martin C

    2016-01-01

    This article reports the revision rate and possible risk factors for lower extremity amputations in patients with diabetes mellitus or peripheral arterial disease (PAD). Data were collected from 421 patients with diabetes mellitus or PAD who underwent amputations of the lower extremity at the authors' institution from 2002 to 2012. There was a 25.2% overall revision rate. Mean time from amputation to revision was 244 days (range, 2-2590 days). Patients with diabetes mellitus had a significantly higher rate of revision to a more proximal level compared with patients without diabetes mellitus (type 1: odds ratio [OR]=3.73; 95% confidence interval [CI], 1.21-11.52; P=.022; and type 2: OR=2.3; 95% CI, 1.07-4.95; P=.033). A significant increase in revision rates was observed from Fontaine stage 0 to IV (stage 0: 17.9%; stage IV, 34.7%; P=.03). Risk factors for revision were diabetic nephropathy (OR=2.26; 95% CI, 1.4-3.63; P=.001) and polyneuropathy (OR=1.68; 95% CI, 1.03-2.73; P=.037). Patients who underwent revision amputation had a significantly younger mean age than patients who did not undergo revision amputation (65.23 years [range, 40-92 years] vs 68.52 years [range, 32-96 years]; P=.013). Anticipated amputation in this patient population requires a multidisciplinary approach with optimization of the patient's health. In the authors' clinical practice, the determination of the appropriate amputation level is performed individually for each patient, considering the risk factors identified in this study and the patient's expected mobilization potential, social background, and acceptance of a more proximal primary amputation level. PMID:26726973

  2. Non-equilibrium and unsteady fluid degassing during slow decompression

    NASA Astrophysics Data System (ADS)

    Hammer, Julia E.; Manga, Michael; Cashman, Katharine V.

    Decompression experiments were performed on corn syrup-water solutions in order to investigate the effect of viscosity on processes of vesiculation and degassing at low to moderate degrees of volatile supersaturation. Repeat experiments demonstrated similar long term vesiculation behavior at moderate decompression rates despite highly variable initial nucleation styles. Results suggest that magmas may not necessarily achieve chemical equilibrium by vapor exsolution and may require viscosity-dependent critical supersaturations in order to vesiculate. Vesiculation also increased the ambient pressure and decreased supersaturations, resulting in unsteady degassing.

  3. Decompression experiments identify kinetic controls on explosive silicic eruptions

    USGS Publications Warehouse

    Mangan, M.T.; Sisson, T.W.; Hankins, W.B.

    2004-01-01

    Eruption intensity is largely controlled by decompression-induced release of water-rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (??Pcritical) triggering gas bubble nucleation. High temperature and pressure decompression experiments using rhyolite and dacite melt reveal compositionally-dependent differences in the ??Pcritical of degassing that may explain why rhyolites have fueled some of the most explosive eruptions on record.

  4. Spatial domain entertainment audio decompression/compression

    NASA Astrophysics Data System (ADS)

    Chan, Y. K.; Tam, Ka Him K.

    2014-02-01

    The ARM7 NEON processor with 128bit SIMD hardware accelerator requires a peak performance of 13.99 Mega Cycles per Second for MP3 stereo entertainment quality decoding. For similar compression bit rate, OGG and AAC is preferred over MP3. The Patent Cooperation Treaty Application dated 28/August/2012 describes an audio decompression scheme producing a sequence of interleaving "min to Max" and "Max to min" rising and falling segments. The number of interior audio samples bound by "min to Max" or "Max to min" can be {0|1|…|N} audio samples. The magnitudes of samples, including the bounding min and Max, are distributed as normalized constants within the 0 and 1 of the bounding magnitudes. The decompressed audio is then a "sequence of static segments" on a frame by frame basis. Some of these frames needed to be post processed to elevate high frequency. The post processing is compression efficiency neutral and the additional decoding complexity is only a small fraction of the overall decoding complexity without the need of extra hardware. Compression efficiency can be speculated as very high as source audio had been decimated and converted to a set of data with only "segment length and corresponding segment magnitude" attributes. The PCT describes how these two attributes are efficiently coded by the PCT innovative coding scheme. The PCT decoding efficiency is obviously very high and decoding latency is basically zero. Both hardware requirement and run time is at least an order of magnitude better than MP3 variants. The side benefit is ultra low power consumption on mobile device. The acid test on how such a simplistic waveform representation can indeed reproduce authentic decompressed quality is benchmarked versus OGG(aoTuv Beta 6.03) by three pair of stereo audio frames and one broadcast like voice audio frame with each frame consisting 2,028 samples at 44,100KHz sampling frequency.

  5. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... minimum pressure capability of— (1) 6 ATA, when used for diving to 300 fsw; or (2) The maximum depth of the dive, when used for diving operations deeper than 300 fsw, unless a closed bell meeting the... minute to 60 fsw and at least 1 ATA per minute thereafter; (j) Have a decompression rate of 1 ATA...

  6. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... minimum pressure capability of— (1) 6 ATA, when used for diving to 300 fsw; or (2) The maximum depth of the dive, when used for diving operations deeper than 300 fsw, unless a closed bell meeting the... minute to 60 fsw and at least 1 ATA per minute thereafter; (j) Have a decompression rate of 1 ATA...

  7. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... minimum pressure capability of— (1) 6 ATA, when used for diving to 300 fsw; or (2) The maximum depth of the dive, when used for diving operations deeper than 300 fsw, unless a closed bell meeting the... minute to 60 fsw and at least 1 ATA per minute thereafter; (j) Have a decompression rate of 1 ATA...

  8. Potential Fifty Percent Reduction in Saturation Diving Decompression Time Using a Combination of Intermittent Recompression and Exercise

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael I.; Abercromby, Andrew; Conklin, Johnny

    2007-01-01

    Conventional saturation decompression protocols use linear decompression rates that become progressively slower at shallower depths, consistent with free gas phase control vs. dissolved gas elimination kinetics. If decompression is limited by control of free gas phase, linear decompression is an inefficient strategy. The NASA prebreathe reduction program demonstrated that exercise during O2 prebreathe resulted in a 50% reduction (2 h vs. 4 h) in the saturation decompression time from 14.7 to 4.3 psi and a significant reduction in decompression sickness (DCS: 0 vs. 23.7%). Combining exercise with intermittent recompression, which controls gas phase growth and eliminates supersaturation before exercising, may enable more efficient saturation decompression schedules. A tissue bubble dynamics model (TBDM) was used in conjunction with a NASA exercise prebreathe model (NEPM) that relates tissue inert gas exchange rate constants to exercise (ml O2/kg-min), to develop a schedule for decompression from helium saturation at 400 fsw. The models provide significant prediction (p < 0.001) and goodness of fit with 430 cases of DCS in 6437 laboratory dives for TBDM (p = 0.77) and with 22 cases of DCS in 159 altitude exposures for NEPM (p = 0.70). The models have also been used operationally in over 25,000 dives (TBDM) and 40 spacewalks (NEPM). The standard U.S. Navy (USN) linear saturation decompression schedule from saturation at 400 fsw required 114.5 h with a maximum Bubble Growth Index (BGI(sub max)) of 17.5. Decompression using intermittent recompression combined with two 10 min exercise periods (75% VO2 (sub peak)) per day required 54.25 h (BGI(sub max): 14.7). Combined intermittent recompression and exercise resulted in a theoretical 53% (2.5 day) reduction in decompression time and theoretically lower DCS risk compared to the standard USN decompression schedule. These results warrant future decompression trials to evaluate the efficacy of this approach.

  9. Spaceflight Decompression Sickness Contingency Plan

    NASA Technical Reports Server (NTRS)

    Dervay, Joseph P.

    2007-01-01

    A viewgraph presentation on the Decompression Sickness (DCS) Contingency Plan for manned spaceflight is shown. The topics include: 1) Approach; 2) DCS Contingency Plan Overview; 3) Extravehicular Activity (EVA) Cuff Classifications; 4) On-orbit Treatment Philosophy; 5) Long Form Malfunction Procedure (MAL); 6) Medical Checklist; 7) Flight Rules; 8) Crew Training; 9) Flight Surgeon / Biomedical Engineer (BME) Training; and 10) DCS Emergency Landing Site.

  10. Eruptive dynamics during magma decompression: a laboratory approach

    NASA Astrophysics Data System (ADS)

    Spina, L.; Cimarelli, C.; Scheu, B.; Wadsworth, F.; Dingwell, D. B.

    2013-12-01

    A variety of eruptive styles characterizes the activity of a given volcano. Indeed, eruptive styles can range from effusive phenomena to explosive eruptions, with related implications for hazard management. Rapid changes in eruptive style can occur during an ongoing eruption. These changes are, amongst other, related to variations in the magma ascent rate, a key parameter affecting the eruptive style. Ascent rate is in turn dependent on several factors such as the pressure in the magma chamber, the physical properties of the magma and the rate at which these properties change. According to the high number of involved parameters, laboratory decompression experiments are the best way to achieve quantitative information on the interplay of each of those factors and the related impact on the eruption style, i.e. by analyzing the flow and deformation behavior of the transparent volatile-bearing analogue fluid. We carried out decompression experiments following different decompression paths and using silicone oil as an analogue for the melt, with which we can simulate a range of melt viscosity values. For a set of experiments we added rigid particles to simulate the presence of crystals in the magma. The pure liquid or suspension was mounted into a transparent autoclave and pressurized to different final pressures. Then the sample was saturated with argon for a fixed amount of time. The decompression path consists of a slow decompression from the initial pressure to the atmospheric condition. Alternatively, samples were decompressed almost instantaneously, after established steps of slow decompression. The decompression path was monitored with pressure transducers and a high-speed video camera. Image analysis of the videos gives quantitative information on the bubble distribution with respect to depth in the liquid, pressure and time of nucleation and on their characteristics and behavior during the ongoing magma ascent. Furthermore, we also monitored the evolution of

  11. [Severe decompression sickness in divers].

    PubMed

    Beuster, W; van Laak, U

    1999-01-01

    The term "decompression illness (DCI)" is a disorder which arises from the presence of ectopic gas bubbles following decompression. Scuba diving poses the risk of two typically clinical syndromes: decompression sickness (DCS) and arterial gas embolism (AGE). DCS results from the formation of gas bubbles in the tissues of the body and in the blood due to rapid reduction of the environmental pressure. AGE is caused by pulmonary overinflation if the breathing gas cannot be exhaled adequately during the ascent. Although the pathophysiological mechanisms of these two disorders are quite different, both of them lead to the same result: inert gas bubbles that may cause impairment of vital functions due to hypoxia. Recognizing the signs and symptoms of DCI is the first step of the therapy. The emergency treatment contains: basic life support, advanced life support--if necessary, horizontal positioning of the victim, administration of 100% normobaric oxygen via face mask or endotracheal tube, rehydration, rapid transportation to the nearest emergency department/hyperbaric facility for definitive treatment in order to prevent serious neurological sequelae. PMID:11315407

  12. [First therapy of decompression injuries].

    PubMed

    Castan, Jan; Wirtz, Sebastian; Moecke, Heinzpeter; Schmidbauer, Willi; Ahlers, Olaf; Kerner, Thoralf

    2010-02-01

    The diving accident is a rare incident for an emergency physician which requires special physical and patho-physiological knowledge. With increasing recreational activities and the fascination of diving also for older persons diving accidents are expected to occur more often. There can be several reasons for diving accidents such as the ignorance of the physics of diving, a trauma under water as well as internistical illnesses like heart attach, stroke or hypoglycaemia. The therapy of the underlying illness should not be left aside while dealing with the patient. The careful rescue and the immobilisation are most important for the initial therapy. The patient should receive oxygen, if possible via a demand valve, until a hyperbaric chamber is reached. There is no specific medical therapy for decompression illness. It is very important that a pre-information is sent to the closest hyperbaric chamber as soon as possible since often the chamber needs some time to be properly prepared for usage. In order to receive information regarding the depth where the diving incident occured, the duration of the diving trip and the decompression stops, it is important to secure the diving computer of the victim for the hyperbaric chamber. Also outside diving, decompression illness can occur, for example working in a tunnel under hyperbaric conditions. These accidents have to be treated according to the same guidelines. PMID:20155636

  13. Crystallization kinetics in magmas during decompression

    NASA Astrophysics Data System (ADS)

    Arzilli, Fabio; Burton, Mike; Carroll, Michael R.

    2016-04-01

    Many variables play a role during magma crystallization at depth or in a volcanic conduit, and through experimentally derived constraints we can better understand pre- and syn-eruptive magma crystallization behavior. The thermodynamic properties of magmas have been extensively investigated as a function of T, P, fO2 and magma composition [1], and this allows estimation of the stability of equilibrium phases and physical parameters (e.g., density, viscosity). However, many natural igneous rocks contain geochemical, mineralogical and textural evidence of disequilibrium, suggesting that magmas frequently follow non-equilibrium, time-dependent pathways that are recorded in the geochemical and petrographic characteristics of the rocks. There are currently no suitable theoretical models capable of calculating nucleation and growth rates in disequilibrium conditions without experimental constraints. The aim of this contribution is provide quantitative data on growth and nucleation rates of feldspar crystals in silicate melts obtained through decompression experiments, in order to determine the magma evolution in pre- and sin-eruptive conditions. Decompression is one of the main processes that induce the crystallization of feldspar during the magma ascent in the volcanic conduit. Decompression experiments have been carried out on trachytic and basaltic melts to investigate crystallization kinetics of feldspar as a function of the effect of the degassing, undercooling and time on nucleation and crystal growth process [2; 3]. Furthermore, feldspar is the main crystals phase present in magmas, and its abundance can strongly vary with small changes in pressure, temperature and water content in the melt, implying appreciable variations in the textures and in the crystallization kinetics. Crystallization kinetics of trachytic melts show that long experiment durations involve more nucleation events of alkali feldspar than short experiment durations [2]. This is an important

  14. Extremely high rate deposition of polymer multilayer optical thin film materials

    SciTech Connect

    Affinito, J.D.

    1993-03-01

    This paper highlights a new technique for extremely high rate deposition of optical dielectric films (vacuum deposition of polymer multilayer thin films). This is a way to produce multilayer optical filters comprised of thousands of layers of either linear or nonlinear optical materials. The technique involves the flash evaporation of an acrylic monomer onto a moving substrate; the monomer is then cured. Acrylic polymers deposited to date are very clear for wavelengths between 0.35 and 2.5 {mu}m; they have extinction coefficients of k{approx}10{sup {minus}7}. Application of electric field during cross linking can polarize (``pole``) the film to greatly enhance the nonlinear optical properties. ``Poling`` films with the polymer multilayer technique offers advantages over conventional approaches, in that the polarization should not decay over time. Battelle`s Pacific Northwest Laboratory is well suited for bringing linear and nonlinear polymer multilayer optical filter technology to manufacturing production status for batch and wide area web applications. 10 figs.

  15. Extremely high rate deposition of polymer multilayer optical thin film materials

    SciTech Connect

    Affinito, J.D.

    1993-01-01

    This paper highlights a new technique for extremely high rate deposition of optical dielectric films (vacuum deposition of polymer multilayer thin films). This is a way to produce multilayer optical filters comprised of thousands of layers of either linear or nonlinear optical materials. The technique involves the flash evaporation of an acrylic monomer onto a moving substrate; the monomer is then cured. Acrylic polymers deposited to date are very clear for wavelengths between 0.35 and 2.5 [mu]m; they have extinction coefficients of k[approx]10[sup [minus]7]. Application of electric field during cross linking can polarize (''pole'') the film to greatly enhance the nonlinear optical properties. ''Poling'' films with the polymer multilayer technique offers advantages over conventional approaches, in that the polarization should not decay over time. Battelle's Pacific Northwest Laboratory is well suited for bringing linear and nonlinear polymer multilayer optical filter technology to manufacturing production status for batch and wide area web applications. 10 figs.

  16. Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-line Regions?

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, W. N.; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Lira, Paulina; Netzer, Hagai; Plotkin, Richard M.; Richards, Gordon T.; Schneider, Donald P.; Strauss, Michael A.

    2010-10-01

    We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad Hβ line and place tight upper limits on the strengths of their [O III] lines. Virial, Hβ-based black hole mass determinations indicate normalized accretion rates of L/L Edd=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of Γ = 1.91+0.24 -0.22, which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

  17. 'Melt welt' mechanism of extreme weakening of gabbro at seismic slip rates.

    PubMed

    Brown, Kevin M; Fialko, Yuri

    2012-08-30

    Laboratory studies of frictional properties of rocks at slip velocities approaching the seismic range (∼0.1-1 m s(-1)), and at moderate normal stresses (1-10 MPa), have revealed a complex evolution of the dynamic shear strength, with at least two phases of weakening separated by strengthening at the onset of wholesale melting. The second post-melting weakening phase is governed by viscous properties of the melt layer and is reasonably well understood. The initial phase of extreme weakening, however, remains a subject of much debate. Here we show that the initial weakening of gabbro is associated with the formation of hotspots and macroscopic streaks of melt ('melt welts'), which partially unload the rest of the slip interface. Melt welts begin to form when the average rate of frictional heating exceeds 0.1-0.4 MW m(-2), while the average temperature of the shear zone is well below the solidus (250-450 °C). Similar heterogeneities in stress and temperature are likely to occur on natural fault surfaces during rapid slip, and to be important for earthquake rupture dynamics. PMID:22932388

  18. WEAK LINE QUASARS AT HIGH REDSHIFT: EXTREMELY HIGH ACCRETION RATES OR ANEMIC BROAD-LINE REGIONS?

    SciTech Connect

    Shemmer, Ohad; Trakhtenbrot, Benny; Netzer, Hagai; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Lira, Paulina; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A.

    2010-10-20

    We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad H{beta} line and place tight upper limits on the strengths of their [O III] lines. Virial, H{beta}-based black hole mass determinations indicate normalized accretion rates of L/L {sub Edd}=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of {Gamma} = 1.91{sup +0.24} {sub -0.22}, which supports the virial L/L {sub Edd} determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

  19. Decompression surgery for spinal metastases: a systematic review.

    PubMed

    Bakar, Dara; Tanenbaum, Joseph E; Phan, Kevin; Alentado, Vincent J; Steinmetz, Michael P; Benzel, Edward C; Mroz, Thomas E

    2016-08-01

    the type of treatment was not significantly associated with the rate of local control. The most commonly reported primary tumor types included lung cancer, prostate cancer, breast cancer, renal cancer, and gastrointestinal cancer. CONCLUSIONS This study reports a systematic review of the literature on decompression surgery for spinal metastases. The results of this study can help educate surgeons on the previously published predictors of outcomes following decompression surgery for metastatic spinal disease. However, the authors also identify significant gaps in the literature and the need for future studies investigating the optimal practice with regard to decompression surgery for spinal metastases. PMID:27476844

  20. Vascular hyperpermeability in pulmonary decompression illness: 'the chokes'.

    PubMed

    Kondo, Yutaka; Shiohira, Shinya; Kamizato, Kota; Teruya, Koji; Fuchigami, Tatsuya; Kakinohana, Manabu; Kukita, Ichiro

    2012-08-01

    Decompression illness (DCI) develops during or after diving. Pulmonary decompression illness ('Chokes') is rarely seen because the affected individual usually dies in the water. We encountered a rare and interesting case. A 60-year-old man complained of leg pain after diving. Despite rapid transfer to a nearby hospital, advanced respiratory failure and shock had set in. He was then transferred to our hospital for hyperbaric oxygen therapy (HBOT). On account of his poor general condition, we initially treated him in the intensive care unit without HBOT, where he showed extreme hyperpermeability and a high level of serum procalcitonin (PCT; 20.24 ng/mL). Despite large-volume fluid therapy, severe intravascular dehydration and shock status remained. We assume that the injured endothelial cells induced vascular hyperpermeability and increased levels of inflammatory cytokines leading to the high serum PCT level. PCT might be a useful stress marker of endothelial damage and severity in DCI, including Chokes. PMID:22862767

  1. On diver thermal status and susceptibility to decompression sickness.

    PubMed

    Gerth, Wayne A

    2015-09-01

    In a recent Letter to the Editor, Clarke, et al, indicated that divers who deliberately chill themselves on a dive to reduce risk of decompression sickness (DCS) may be misinterpreting our 2007 Navy Experimental Diving Unit (NEDU) report. Indeed, we did not advocate that divers should risk hypothermia on bottom to reduce risk of DCS, nor do we dispute the authors' overall admonition to avoid diving cold unnecessarily. However, Clarke, et al, imply more generally that results of our study are not applicable to recreational or technical divers because the dives we tested were atypical of dives undertaken by such divers. We wish to clarify that our study does have implications for recreational and technical divers, implications that should not be ignored. The dives we tested were not intended to be typical of dives undertaken in any actual operational context. Instead, we chose to expose divers to temperatures at the extremes of their thermal tolerance in order to ensure that effects of diver thermal status on DCS susceptibility would be found if such effects existed. Our initial test dive profile provided appreciable time both on bottom and during decompression to allow any differential thermal effects during these two dive phases to manifest, while affording a baseline risk of DCS that could be altered by thermal effects without exposing subjects to inordinately high risks of DCS. Our results strongly indicate that the optimal diver thermal conditions for mitigation of DCS risk or minimization of decompression time entail remaining cool during gas uptake phases of a dive and warm during off-gassing phases. While the dose-response characteristics of our observed thermal effects are almost certainly non-linear in both exposure temperature and duration, it is only reasonable to presume that the effects vary monotonically with these factors. We have no reason to presume that such responses and effects under less extreme conditions would be in directions opposite to

  2. [Percutaneous laser disk decompression. Experience since 1989].

    PubMed

    Siebert, W E; Berendsen, B T; Tollgaard, J

    1996-02-01

    Since 1987/1988 percutaneous laser disc decompression (PLDD) has been used clinically for treatment of intervertebral disc prolapses. Credible prospective investigations that have been conducted since 1989 with large patient collectives are now available for analysis of their medium-term results and comparison with other minimally invasive procedures. Our follow-up examination of the first 180 patients treated with PLDD from 1989 to 1993 shows a success rate of 72.8%, similar to that with other percutaneous techniques (automated percutaneous lumbar discectomy, percutaneous lumbar discectomy, chemonucleolysis). To guarantee success, the spinal surgeon must have command of the correct technique and also use the appropriate instruments. Good results with the PLDD procedure can be procured when contraindications and indications for patient selection are strictly observed. Overall, our 5 year results seem encouraging. PMID:8622845

  3. Paradoxical Herniation After Unilateral Decompressive Craniectomy Predicts Better Patient Survival

    PubMed Central

    Chen, Weiqiang; Guo, Jingfang; Wu, Jin; Peng, Guoyi; Huang, Mindong; Cai, Chuwei; Yang, Yingming; Wang, Shousen

    2016-01-01

    Abstract Paradoxical herniation (PH) is a life-threatening emergency after decompressive craniectomy. In the current study, we examined patient survival in patients who developed PH after decompressive craniectomy versus those who did not. Risk factors for, and management of, PH were also analyzed. This retrospective analysis included 429 consecutive patients receiving decompressive craniectomy during a period from January 2007 to December 2012. Mortality rate and Glasgow Outcome Scale (GOS) were compared between those who developed PH (n = 13) versus those who did not (n = 416). A stepwise multivariate logistic regression analysis was carried out to examine the risk factors for PH. The overall mortality in the entire sample was 22.8%, with a median follow-up of 6 months. Oddly enough, all 13 patients who developed PH survived beyond 6 months. Glasgow Coma Scale did not differ between the 2 groups upon admission, but GOS was significantly higher in subjects who developed PH. Both the disease type and coma degree were comparable between the 13 PH patients and the remaining 416 patients. In all PH episodes, patients responded to emergency treatments that included intravenous hydration, cerebral spinal fluid drainage discontinuation, and Trendelenburg position. A regression analysis indicated the following independent risk factors for PH: external ventriculostomy, lumbar puncture, and continuous external lumbar drainage. The rate of PH is approximately 3% after decompressive craniectomy. The most intriguing findings of the current study were the 0% mortality in those who developed PH versus 23.6% mortality in those who did not develop PH and significant difference of GOS score at 6-month follow-up between the 2 groups, suggesting that PH after decompressive craniectomy should be managed aggressively. The risk factors for PH include external ventriculostomy, ventriculoperitoneal shunt, lumbar puncture, and continuous external lumbar drainage. PMID:26945365

  4. Endoscopic and Microscopic Microvascular Decompression.

    PubMed

    Piazza, Matthew; Lee, John Y K

    2016-07-01

    The introduction of the endoscope into the neurosurgeon's armamentarium has revolutionized ventral and anterior skull-base surgery and, more recently, has been used in the surgical treatment of cerebellopontine angle (CPA) pathology. The utilization of the endoscope in microvascular decompression (MVD) for trigeminal neuralgia and other associated cranial nerve hyperactivity syndromes allows for unparalleled panoramic views and illumination of the neurovascular structures within the CPA and identification of vessel-nerve contact traditionally unseen using the microscope. In this article, the technical advantages and challenges of using the endoscope for MVD, operative technique, and patient outcomes of endoscopic MVD are discussed. PMID:27324997

  5. Evaluation of satellite-retrieved extreme precipitation rates across the central United States

    NASA Astrophysics Data System (ADS)

    Aghakouchak, A.; Behrangi, A.; Sorooshian, S.; Hsu, K.; Amitai, E.

    2011-01-01

    Water resources management, forecasting, and decision making require reliable estimates of precipitation. Extreme precipitation events are of particular importance because of their severe impact on the economy, the environment, and the society. In recent years, the emergence of various satellite-retrieved precipitation products with high spatial resolutions and global coverage have resulted in new sources of uninterrupted precipitation estimates. However, satellite-based estimates are not well integrated into operational and decision-making applications because of a lack of information regarding the associated uncertainties and reliability of these products. In this study, four satellite-derived precipitation products (CMORPH, PERSIANN, TMPA-RT, and TMPA-V6) are evaluated with respect to their performance in capturing precipitation extremes. The Stage IV (radar-based, gauge-adjusted) precipitation estimates are used as reference data. The results show that with respect to the probability of detecting extremes and the volume of correctly identified precipitation, CMORPH and PERSIANN data sets lead to better estimates. However, their false alarm ratio and volume are higher than those of TMPA-RT and TMPA-V6. Overall, no single precipitation product can be considered ideal for detecting extreme events. In fact, all precipitation products tend to miss a significant volume of rainfall. With respect to verification metrics used in this study, the performance of all satellite products tended to worsen as the choice of extreme precipitation threshold increased. The analyses suggest that extensive efforts are necessary to develop algorithms that can capture extremes more reliably.

  6. Response Styles in Rating Scales: Simultaneous Modeling of Content-Related Effects and the Tendency to Middle or Extreme Categories

    ERIC Educational Resources Information Center

    Tutz, Gerhard; Berger, Moritz

    2016-01-01

    Heterogeneity in response styles can affect the conclusions drawn from rating scale data. In particular, biased estimates can be expected if one ignores a tendency to middle categories or to extreme categories. An adjacent categories model is proposed that simultaneously models the content-related effects and the heterogeneity in response styles.…

  7. Lu Hf and Ar Ar chronometry supports extreme rate of subduction zone metamorphism deduced from geospeedometry

    NASA Astrophysics Data System (ADS)

    Philippot, Pascal; Blichert-Toft, Janne; Perchuk, Alexei; Costa, Sylvie; Gerasimov, Vladimir

    2001-12-01

    temperatures are equivalent to or in the upper range of peak metamorphic temperatures. With respect to Ar, calculated closure temperatures of 570 °C for the Yukon eclogites and 560-600 °C for the Great Caucasus eclogites are within error of the temperatures of the early stage of cooling and/or exhumation. These results indicate that the eclogitic rocks experienced a minimum cooling and exhumation of about 150 °C and 25 km in a time interval smaller than the errors on the ages. The fact that garnet and phengite yield indistinguishable Lu-Hf and Ar-Ar ages is in good agreement with the observation deduced from geospeedometry that the time elapsed at eclogitic conditions should be extremely short (of the order of 1 Ma). Considering the exceptional precision of the age information obtained on eclogitic garnet using the Lu-Hf technique and that Lu-Hf, Ar-Ar and geospeedometry approaches were carried out the same samples, these results suggest that the time-scale resolution required for unraveling rates of high-pressure metamorphism remains out of reach of current thermochronological methods.

  8. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox

    PubMed Central

    Kot, Jacek; Sicko, Zdzislaw

    2015-01-01

    Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window—also called inherent unsaturation or partial pressure vacancy—but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of

  9. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox.

    PubMed

    Kot, Jacek; Sicko, Zdzislaw; Doboszynski, Tadeusz

    2015-01-01

    Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window--also called inherent unsaturation or partial pressure vacancy--but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of

  10. Graphics processing unit-assisted lossless decompression

    DOEpatents

    Loughry, Thomas A.

    2016-04-12

    Systems and methods for decompressing compressed data that has been compressed by way of a lossless compression algorithm are described herein. In a general embodiment, a graphics processing unit (GPU) is programmed to receive compressed data packets and decompress such packets in parallel. The compressed data packets are compressed representations of an image, and the lossless compression algorithm is a Rice compression algorithm.

  11. Cervical Cord Decompression Using Extended Anterior Cervical Foraminotomy Technique

    PubMed Central

    Kim, Sung-Duk; Lee, Cheol-Young; Kim, Hyun-Woo; Jung, Chul-Ku; Kim, Jong Hyun

    2014-01-01

    Objective At present, gold-standard technique of cervical cord decompression is surgical decompression and fusion. But, many complications related cervical fusion have been reported. We adopted an extended anterior cervical foraminotomy (EACF) technique to decompress the anterolateral portion of cervical cord and report clinical results and effectiveness of this procedure. Methods Fifty-three patients were operated consecutively using EACF from 2008 to 2013. All of them were operated by a single surgeon via the unilateral approach. Twenty-two patients who exhibited radicular and/or myelopathic symptoms were enrolled in this study. All of them showed cervical cord compression in their preoperative magnetic resonance scan images. Results In surgical outcomes, 14 patients (64%) were classified as excellent and six (27%), as good. The mean difference of cervical cord anterior-posterior diameter after surgery was 0.92 mm (p<0.01) and transverse area was 9.77 mm2 (p<0.01). The dynamic radiological study showed that the average post-operative translation (retrolisthesis) was 0.36 mm and the disc height loss at the operated level was 0.81 mm. The change in the Cobb angle decreased to 3.46, and showed slight kyphosis. The average vertebral body resection rate was 11.47%. No procedure-related complications occurred. Only one patient who had two-level decompression needed anterior fusion at one level as a secondary surgery due to postoperative instability. Conclusions Cervical cord decompression was successfully performed using EACF technique. This procedure will be an alternative surgical option for treating cord compressing lesions. Long-term follow-up and a further study in larger series will be needed. PMID:25328648

  12. Xenon Blocks Neuronal Injury Associated with Decompression.

    PubMed

    Blatteau, Jean-Eric; David, Hélène N; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H

    2015-01-01

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS. PMID:26469983

  13. Xenon Blocks Neuronal Injury Associated with Decompression

    PubMed Central

    Blatteau, Jean-Eric; David, Hélène N.; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H.

    2015-01-01

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS. PMID:26469983

  14. Orthostatic mesodiencephalic dysfunction after decompressive craniectomy.

    PubMed

    Bijlenga, Philippe; Zumofen, Daniel; Yilmaz, Hasan; Creisson, Eric; de Tribolet, Nicolas

    2007-04-01

    An extreme syndrome of the trephined after decompressive craniectomy is reported here. The most extensive clinical syndrome observed was established over 4 weeks and consisted of bradypsychia, dysartria, and limb rigidity with equine varus feet predominating on the right. The syndrome was aggravated when the patient was sitting with the sequential appearance over minutes of a typical parkinsonian levodopa-resistant tremor starting on the right side, extending to all four limbs, followed by diplopia resulting from a left abducens nerve palsy followed by a left-sided mydriasis. All signs recovered within 1-2 h after horizontalisation. It was correlated with an orthostatic progressive sinking of the skin flap, MRI and CT scan mesodiencephalic distortion without evidence of parenchymal lesion. Brain stem auditory evoked potential wave III latency increases were observed on the right side on verticalisation of the patient. EEG exploration excluded any epileptic activity. Symptoms were fully recovered within 2 days after cranioplasty was performed. The cranioplasty had to be removed twice due to infection. Bradypsychia, speech fluency, limb rigidity and tremor reappeared within a week after removal of the prosthesis. While waiting for sterilisation of the operative site, the symptoms were successfully prevented by a custom-made transparent suction-cup helmet before completion of cranioplasty. PMID:17119005

  15. Drop-box Weir for Measuring Flow Rates Under Extreme Flow Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment and large rocks often are transported in runoff during extreme events. The sediment can deposit in a runoff-measuring structure and give erroneous readings. The drop-box weir (DBW) is one of only a few flow-measuring devices capable of measuring sediment-laden flows. Recent studies have ...

  16. Putative extremely high rate of proteome innovation in lancelets might be explained by high rate of gene prediction errors

    PubMed Central

    Bányai, László; Patthy, László

    2016-01-01

    A recent analysis of the genomes of Chinese and Florida lancelets has concluded that the rate of creation of novel protein domain combinations is orders of magnitude greater in lancelets than in other metazoa and it was suggested that continuous activity of transposable elements in lancelets is responsible for this increased rate of protein innovation. Since morphologically Chinese and Florida lancelets are highly conserved, this finding would contradict the observation that high rates of protein innovation are usually associated with major evolutionary innovations. Here we show that the conclusion that the rate of proteome innovation is exceptionally high in lancelets may be unjustified: the differences observed in domain architectures of orthologous proteins of different amphioxus species probably reflect high rates of gene prediction errors rather than true innovation. PMID:27476717

  17. Symptomatic posterior fossa and supratentorial subdural hygromas as a rare complication following foramen magnum decompression for Chiari malformation Type I.

    PubMed

    Bahuleyan, Biji; Menon, Girish; Hariharan, Easwer; Sharma, Mridul; Nair, Suresh

    2011-02-01

    Symptomatic subdural hygroma due to foramen magnum decompression for Chiari malformation Type I is extremely rare. The authors present their experience with 2 patients harboring such lesions and discuss treatment issues. They conclude that the possibility of subdural hygromas should be considered in all patients presenting with increased intracranial tension following foramen magnum decompression for Chiari malformation Type I. Immediate neuroimaging and appropriate surgical intervention provides a good outcome. PMID:20849216

  18. Architecture for hardware compression/decompression of large images

    NASA Astrophysics Data System (ADS)

    Akil, Mohamed; Perroton, Laurent; Gailhard, Stephane; Denoulet, Julien; Bartier, Frederic

    2001-04-01

    In this article, we present a popular loseless compression/decompression algorithm, GZIP, and the study to implement it on a FPGA based architecture. The algorithm is loseless, and applied to 'bi-level' images of large size. It insures a minimum compression rate for the images we are considering. The proposed architecture for the compressor is based ona hash table and the decompressor is based on a parallel decoder of the Huffman codes.

  19. Bright high-repetition-rate source of narrowband extreme-ultraviolet harmonics beyond 22 eV

    SciTech Connect

    Wang, He; Xu, Yiming; Ulonska, Stefan; Robinson, Joseph S.; Ranitovic, Predrag; Kaindl, Robert A.

    2015-06-11

    Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials or correlated solids, and enable advanced applications in imaging or metrology. Extending high-harmonic generation to high repetition rates portends great experimental benefits, yet efficient extreme-ultraviolet conversion of correspondingly weak driving pulses is challenging. In this article, we demonstrate a highly-efficient source of femtosecond extreme-ultraviolet pulses at 50-kHz repetition rate, utilizing the ultraviolet second-harmonic focused tightly into Kr gas. In this cascaded scheme, a photon flux beyond ≈3 × 1013 s-1 is generated at 22.3 eV, with 5 × 10-5 conversion efficiency that surpasses similar harmonics directly driven by the fundamental by two orders-of-magnitude. The enhancement arises from both wavelength scaling of the atomic dipole and improved spatio-temporal phase matching, confirmed by simulations. Finally, spectral isolation of a single 72-meV-wide harmonic renders this bright, 50-kHz extreme-ultraviolet source a powerful tool for ultrafast photoemission, nanoscale imaging and other applications.

  20. Bright high-repetition-rate source of narrowband extreme-ultraviolet harmonics beyond 22 eV

    PubMed Central

    Wang, He; Xu, Yiming; Ulonska, Stefan; Robinson, Joseph S.; Ranitovic, Predrag; Kaindl, Robert A.

    2015-01-01

    Novel table-top sources of extreme-ultraviolet light based on high-harmonic generation yield unique insight into the fundamental properties of molecules, nanomaterials or correlated solids, and enable advanced applications in imaging or metrology. Extending high-harmonic generation to high repetition rates portends great experimental benefits, yet efficient extreme-ultraviolet conversion of correspondingly weak driving pulses is challenging. Here, we demonstrate a highly-efficient source of femtosecond extreme-ultraviolet pulses at 50-kHz repetition rate, utilizing the ultraviolet second-harmonic focused tightly into Kr gas. In this cascaded scheme, a photon flux beyond ≈3 × 1013 s−1 is generated at 22.3 eV, with 5 × 10−5 conversion efficiency that surpasses similar harmonics directly driven by the fundamental by two orders-of-magnitude. The enhancement arises from both wavelength scaling of the atomic dipole and improved spatio-temporal phase matching, confirmed by simulations. Spectral isolation of a single 72-meV-wide harmonic renders this bright, 50-kHz extreme-ultraviolet source a powerful tool for ultrafast photoemission, nanoscale imaging and other applications. PMID:26067922

  1. libpolycomp: Compression/decompression library

    NASA Astrophysics Data System (ADS)

    Tomasi, Maurizio

    2016-04-01

    Libpolycomp compresses and decompresses one-dimensional streams of numbers by means of several algorithms. It is well-suited for time-ordered data acquired by astronomical instruments or simulations. One of the algorithms, called "polynomial compression", combines two widely-used ideas (namely, polynomial approximation and filtering of Fourier series) to achieve substantial compression ratios for datasets characterized by smoothness and lack of noise. Notable examples are the ephemerides of astronomical objects and the pointing information of astronomical telescopes. Other algorithms implemented in this C library are well known and already widely used, e.g., RLE, quantization, deflate (via libz) and Burrows-Wheeler transform (via libbzip2). Libpolycomp can compress the timelines acquired by the Planck/LFI instrument with an overall compression ratio of ~9, while other widely known programs (gzip, bzip2) reach compression ratios less than 1.5.

  2. The Effect of Biliary Decompression on Bacterial Translocation in Jaundiced Rats

    PubMed Central

    Ding, Jin Wen; Soltesz, Vasile; Willén, Roger; Loft, Steffen; Poulsen, Henrik E.; Pärsson, Håkan; Olsson, Kjell; Bengmark, Stig

    1993-01-01

    Patients with obstructive jaundice are prone to septic complications after biliary tract operations. Restoring bile flow to the intestine may help to decrease the complication rate. The present study is aimed at evaluating the effect of biliary decompression on bacterial translocation in jaundiced rats. Sixty-six male Sprague-Dawley rats were randomly allocated to six groups subjected to common bile duct ligation (CBDL) and transection (groups 2–6) or sham operation (group 1). In groups and 2 the incidence of enteric bacterial translocation was determined 2 weeks after sham operation or CBDL. In groups 3–6, biliary decompression was achieved by performing a choledochoduodenostomy after 2 weeks of biliary decompression. Bacterial translocation was then studied 1,2,3 and 5 weeks following biliary decompression. The rate of bacterial translocation to mesenteric lymph nodes in obstructive jaundice was significantly higher as compared with controls, and decreased with time to nil three weeks following biliary decompression. The incidence of bacterial translocation was closely correlated (r = 0.844; p = 0.034) with serum alkaline phosphatase activity and seemed to fit with the morphological changes noted in the small intestine. The decrease in bacterial translocation, however, lags behind the recovery of liver function as measured by routine liver function tests and antipyrine clearance. Obstructive jaundice thus promotes bacterial translocation in the rat. Biliary decompression gradually decreases the rate of bacterial translocation. PMID:8268113

  3. Investigating degassing dynamics into the shallow conduit through decompression experiments

    NASA Astrophysics Data System (ADS)

    Spina, Laura; Scheu, Bettina; Cimarelli, Corrado; Dingwell, Donald

    2014-05-01

    The history of bubbles' growth and interaction, as well as their spatial distribution in the shallow conduit, is deeply interconnected with the style of the eruptions. According to the fundamental role played by volatiles in the eruptive process, more effort is required in determining how the key factors of volcanic systems (i.e., magma properties, decompression rate) influence the dynamics of degassing. Therefore, our aim is to provide, through the analysis of decompression experiments on analogue materials, insights on such relations. We performed several decompression experiments with a shock-tube apparatus, and using silicon oil as laboratory-analogue for the magmatic melt. The sample was placed in a transparent autoclave, saturated with Argon for an established amount of time under a fixed pressure (up to a maximum of 10 MPa). Successively it was decompressed to atmospheric conditions, by releasing gas through a control valve. The dynamics of gas exsolution processes were recorded by using pressure sensors and a high speed camera. A range of viscosity values (1, 10, 100, 1000 Pa s) was investigated, for the same decompression path. Furthermore, some experiments were carried out with the addition of glass beads, as analogue to crystals, to the pure liquid. The height of the expanding column was monitored, in conjunction with images recorded during the experiments, and the growth rate of bubbles was measured at different times and depth. Finally, bubble size distribution has been evaluated at various stages for some experiments, in order to achieve a spatial map of the ongoing degassing phenomena. Results allowed us to define different regimes occurring during the decompression, whose features and characteristics are strongly affected by fluid viscosity. Indeed, several degassing phases were observed, from bubbly fluid to the eventual buildup of a more or less "foamy" phase, which ultimately experiences periodical oscillations around an average equilibrium level

  4. Decompression Sickness during Construction of the Dartford Tunnel

    PubMed Central

    Golding, F. Campbell; Griffiths, P.; Hempleman, H. V.; Paton, W. D. M.; Walder, D. N.

    1960-01-01

    A clinical, radiological and statistical survey has been made of decompression sickness during the construction of the Dartford Tunnel. Over a period of two years, 1,200 men were employed on eight-hour shifts at pressures up to 28 pounds per square inch (p.s.i.). There were 689 cases of decompression sickness out of 122,000 compressions, an incidence of 0·56%. The majority of cases (94·9%) were simple “bends”. The remainder (5·1%) exhibited signs and symptoms other than pain and were more serious. All cases were successfully treated and no fatality or permanent disability occurred. In two serious cases, cysts in the lungs were discovered. It is suggested that these gave rise to air embolism when the subjects were decompressed, and pulmonary changes may contribute more than hitherto believed to the pathogenesis of bends. Some other clinical features are described, including “skin-mottling” and an association between bends and the site of an injury. The bends rate is higher for the back shift (3 p.m. to 11 p.m.) and the night shift (11 p.m. to 7 a.m.) than for the day shift. In the treatment of decompression sickness it appears to be more satisfactory to use the minimum pressure required for relief of symptoms followed by slow decompression with occasional “soaks”, than to attempt to drive the causative bubbles into solution with high pressures. During the contract the decompression tables recently prescribed by the Ministry of Labour were used. Evidence was obtained that they could be made safer, and that the two main assumptions on which they are based (that sickness will not occur at pressures below 18 p.s.i., and that a man saturates in four hours) may be incorrect. It is desirable to test tables based on 15 p.s.i. and eight-hour saturation. The existence of acclimatization to pressure was confirmed; it is such that the bends rate may fall in two to three weeks to 0·1% of the incidence on the first day of exposure. Acclimatization is lost again

  5. Is carpal tunnel decompression warranted for HNPP?

    PubMed

    Earle, Nicholas; Zochodne, Douglas W

    2013-12-01

    The role of carpal tunnel decompression surgery for patients that have hereditary neuropathy with liability to pressure palsy (HNPP) is currently unknown. Since recovery from carpal tunnel compression is often associated with remyelination or nodal reconstruction rather than axonal regeneration, it is uncertain whether the PMP22 deletion associated with HNPP interrupts myelin or nodal reconstitution. We describe two patients with genetically confirmed HNPP and symptomatic carpal tunnel syndrome that had clinical and electrophysiological improvement after surgical decompression. The findings indicate a capacity for conduction repair in HNPP. They also suggest a need for further investigation and discussion around whether to offer carpal tunnel decompression to symptomatic HNPP patients. PMID:24171697

  6. Client side decompression technique provides faster DNA sequence data delivery.

    PubMed

    Sufi, Fahim; Fang, Qiang; Cosic, Irena; Ferguson, Roy

    2005-01-01

    DNA sequences are generally very long chains of sequentially linked nucleotides. There are four different nucleotides and combinations of these build the nucleotide information of sequence files contained in data sources. When a user searches for any sequence for an organism, a compressed sequence file can be sent from the data source to the user. The compressed file then can be decompressed at the client end resulting in reduced transmission time over the Internet. A compression algorithm that provides a moderately high compression rate with minimal decompression time is proposed in this paper. We also compare a number of different compression techniques for achieving efficient delivery methods from an intelligent genomic search agent over the Internet. PMID:17282828

  7. Swimming movements initiate bubble formation in fish decompressed from elevated gas pressures.

    PubMed

    McDonough, P M; Hemmingsen, E A

    1985-01-01

    Young specimens of trout, catfish, sculpin and salamanders were equilibrated with elevated gas pressures, then rapidly decompressed to ambient pressure. The newly hatched forms tolerated extremely high gas supersaturations; equilibration pressures of 80-120 atm argon or 150-250 atm helium were required for in vivo bubble formation. During subsequent larval development, the equilibration pressures required decreased to just 5-10 atm and bubbles originated in the fins. Anesthetising older fish before decompression prevented bubble formation in the fins; this suggests that swimming movements mechanically initiate bubbles, possibly by a tribonucleation mechanism. PMID:2859954

  8. Evidence Report: Risk of Decompression Sickness (DCS)

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Norcross, Jason R.; Wessel, James H., III; Klein, Jill S.; Dervay, Joseph P.; Gernhardt, Michael L.

    2016-01-01

    Given that tissue inert gas partial pressure is often greater than ambient pressure during phases of a mission, primarily during extravehicular activity (EVA), there is a possibility of decompression sickness (DCS).

  9. Revision surgery for Chiari malformation decompression.

    PubMed

    Mazzola, Catherine A; Fried, Arno H

    2003-09-15

    Chiari malformations comprise four different hindbrain anomalies originally described by Hans Chiari, a professor of pathology at the German University in Prague. There are four basic Chiari malformations. The reasons for revision of Chiari malformation decompression may be for conservative or inadequate initial decompression or the development of postoperative complications. Another reason involves cases of both hindbrain herniation and syringomyelia in patients who have undergone adequate posterior fossa decompression without resolution of symptoms, signs, or radiological appearance of their syrinx cavity. Additionally, symptom recurrence has been reported in association with various types of dural grafts. Reoperation or revision surgery for patients with Chiari malformations is common and may not be due to technical error or inadequate decompression. The types of revision surgeries, their indications, and initial presentations will be reviewed. PMID:15347221

  10. Orbital decompression in thyroid eye disease.

    PubMed

    Fichter, N; Guthoff, R F; Schittkowski, M P

    2012-01-01

    Though enlargement of the bony orbit by orbital decompression surgery has been known for about a century, surgical techniques vary all around the world mostly depending on the patient's clinical presentation but also on the institutional habits or the surgeon's skills. Ideally every surgical intervention should be tailored to the patient's specific needs. Therefore the aim of this paper is to review outcomes, hints, trends, and perspectives in orbital decompression surgery in thyroid eye disease regarding different surgical techniques. PMID:24558591

  11. Orbital Decompression in Thyroid Eye Disease

    PubMed Central

    Fichter, N.; Guthoff, R. F.; Schittkowski, M. P.

    2012-01-01

    Though enlargement of the bony orbit by orbital decompression surgery has been known for about a century, surgical techniques vary all around the world mostly depending on the patient's clinical presentation but also on the institutional habits or the surgeon's skills. Ideally every surgical intervention should be tailored to the patient's specific needs. Therefore the aim of this paper is to review outcomes, hints, trends, and perspectives in orbital decompression surgery in thyroid eye disease regarding different surgical techniques. PMID:24558591

  12. Extreme multi-millennial slip rate variations on the Garlock fault, California: geomorphology and geochronology of slip rate constraints

    NASA Astrophysics Data System (ADS)

    Rhodes, Edward; Dolan, James; McGill, Sally; McAuliffe, Lee; Zinke, Robert

    2016-04-01

    Combining existing paleoseismology with new geomorphic constraints for the same part of the Central Garlock fault in California, USA, allows us to demonstrate pronounced variations in slip rate during the Holocene for this left-lateral strike-slip system. Our results have basic implications for understanding how faults store and release strain energy in large earthquakes, and for Probabilistic Seismic Hazard Assessment (PSHA). A series of well-preserved fluvial terraces within alluvial fans provide offset markers, and newly developed single grain K-feldspar IRSL dating allows us to constrain depositional ages and subsequent erosion of terrace risers with good precision, using multiple samples from several different locations. This new dating approach has wide applicability for paleoseismology and slip rate studies, besides understanding environmental response to climatic events; agreement with independent age control provided by C-14 and Be-10 profiles comes from sites in the USA, Mexico, Tibet and Mongolia. Sediments dominated by a range of grain sizes from silt to boulders can be dated, and the technique is often applicable in locations where quartz OSL does not work well. We examine the interplay and coupling between climate and tectonics at millennial timescales, along with sedimentary and geomorphic responses, and consider how our understanding of fault dynamics can be improved with the benefit of these new approaches.

  13. On-the-Fly Decompression and Rendering of Multiresolution Terrain

    SciTech Connect

    Lindstrom, P; Cohen, J D

    2009-04-02

    We present a streaming geometry compression codec for multiresolution, uniformly-gridded, triangular terrain patches that supports very fast decompression. Our method is based on linear prediction and residual coding for lossless compression of the full-resolution data. As simplified patches on coarser levels in the hierarchy already incur some data loss, we optionally allow further quantization for more lossy compression. The quantization levels are adaptive on a per-patch basis, while still permitting seamless, adaptive tessellations of the terrain. Our geometry compression on such a hierarchy achieves compression ratios of 3:1 to 12:1. Our scheme is not only suitable for fast decompression on the CPU, but also for parallel decoding on the GPU with peak throughput over 2 billion triangles per second. Each terrain patch is independently decompressed on the fly from a variable-rate bitstream by a GPU geometry program with no branches or conditionals. Thus we can store the geometry compressed on the GPU, reducing storage and bandwidth requirements throughout the system. In our rendering approach, only compressed bitstreams and the decoded height values in the view-dependent 'cut' are explicitly stored on the GPU. Normal vectors are computed in a streaming fashion, and remaining geometry and texture coordinates, as well as mesh connectivity, are shared and re-used for all patches. We demonstrate and evaluate our algorithms on a small prototype system in which all compressed geometry fits in the GPU memory and decompression occurs on the fly every rendering frame without any cache maintenance.

  14. Effective Decompression of JPEG Document Images.

    PubMed

    Pham, The-Anh; Delalandre, Mathieu

    2016-08-01

    This paper concentrates on developing an effective approach for decompressing JPEG document images. Our main goal is targeted to time-critical applications, especially to those situated on mobile network infrastructures. To this aim, the proposed approach is designed to work either in the transform domain or image spatial plane. Specifically, the image blocks are first classified into smooth blocks (e.g., background and uniform regions) and non-smooth blocks (e.g., text, graphics, and line-drawings). Next, the smooth blocks are fully decoded in the transform domain by minimizing the total block boundary variation, which is very efficient to compute. For decoding non-smooth blocks, a novel text model is presented that accounts for the specifics of document content. In addition, an efficient optimization algorithm is introduced to reconstruct the non-smooth blocks. The proposed approach has been validated by extensive experiments, demonstrating a significant improvement of visual quality, assuming that document images have been encoded at low bit rates and thus are subject to severe distortion. PMID:27295665

  15. Use of ultrasound in altitude decompression modeling

    NASA Technical Reports Server (NTRS)

    Olson, Robert M.; Pilmanis, Andrew A.

    1993-01-01

    A model that predicts the probability of developing decompression sickness (DCS) with various denitrogenation schedules is being developed by the Armstrong Laboratory, using human data from previous exposures. It was noted that refinements are needed to improve the accuracy and scope of the model. A commercially developed ultrasonic echo imaging system is being used in this model development. Using this technique, bubbles images from a subject at altitude can be seen in the gall bladder, hepatic veins, vena cava, and chambers of the heart. As judged by their motion and appearance in the vena cava, venous bubbles near the heart range in size from 30 to 300 M. The larger bubbles skim along the top, whereas the smaller ones appear as faint images near the bottom of the vessel. Images from growing bubbles in a model altitude chamber indicate that they grow rapidly, going from 20 to 100 M in 3 sec near 30,000 ft altitude. Information such as this is valuable in verifying those aspects of the DCS model dealing with bubble size, their growth rate, and their site of origin.

  16. Extremely High Magma Emplacement Rates Recorded in the Golden Horn Batholith, WA

    NASA Astrophysics Data System (ADS)

    Eddy, M. P.; Bowring, S. A.; Tepper, J. H.; Miller, R. B.

    2015-12-01

    High SiO2 rhyolites emplaced during 'super-eruptions' demonstrate that large volumes of eruptible magma can exist in the upper crust. However, the timescale over which the magma reservoirs that source these eruptions are built remains controversial. Thermal models suggest that magma emplacement rates need to be > 0.005-0.01 km3/yr in order to accumulate enough eruptible magma to source a 'super-eruption'. Yet, these rates are higher than the time-averaged rates (< 0.001 km3/yr) for nearly all well-studied granitoid plutonic complexes. This disparity contradicts geologic evidence suggesting that the high SiO2 rhyolites emplaced during 'super-eruptions' are extracted from crystal rich magma chambers that should be preserved in the geologic record as granodioritic and granitic plutons. We quantify time-averaged magma emplacement rates for the upper crustal Golden Horn batholith, WA based on new geologic mapping and U-Pb zircon CA-IDTIMS geochronology. The batholith is exposed over 310 km3 and can be separated in the field into five intrusive units. High topography allows the 3D geometry of each phase to be constrained and their volumes range from < 100 km3 to > 400 km3. U-Pb zircon geochronology reveals that four of the five phases were assembled incrementally and distinct zircon populations from samples within these phases suggest that individual magmatic pulses had fully crystallized before the next arrived. However, six nearly identical U-Pb zircon dates from a > 400 km3 rapakivi granite show that this phase was built in ca. 50 kyr and that large portions may have been emplaced nearly simultaneously. The implied emplacement rate for this phase (≥ 0.008 km3/yr) is in agreement with those predicted for assembly of the upper crustal magma chambers that source 'super-eruptions', and it may provide a rare and unprecedented opportunity to study the processes that occur in such chambers.

  17. Use of psychological decompression in military operational environments.

    PubMed

    Hughes, Jamie G H Hacker; Earnshaw, N Mark; Greenberg, Neil; Eldridge, Rod; Fear, Nicola T; French, Claire; Deahl, Martin P; Wessely, Simon

    2008-06-01

    This article reviews the use of psychological decompression as applied to troops returning from active service in operational theaters. Definitions of the term are considered and a brief history is given. Current policies and practices are described and the question of mandatory decompression is considered. Finally, the evidence base for the efficacy of decompression is examined and some conclusions are drawn. This article highlights variations in the definition and practice of decompression and its use. Although there is, as yet, no evidence that decompression works, there is also no evidence to the contrary. Given the lack of knowledge as to the balance of risks and benefits of decompression and the absence of any definitive evidence that decompression is associated with improved mental health outcomes or that lack of decompression is associated with the reverse, it is argued that the use of decompression should remain a matter for discretion. PMID:18595415

  18. Dynamic Phase Relations in Ascending Silicic Magmas: Insights from Experimental Decompression of Mount St. Helens Rhyodacite

    NASA Astrophysics Data System (ADS)

    Riker, J. M.; Blundy, J. D.; Rust, A.

    2011-12-01

    Ascent-driven degassing and crystallization play a major role in modulating the chemical and physical properties of erupting magmas. Previous experimental studies of ascent-driven crystallization have focused on instantaneous or stepped decompression, measuring a response to discrete imposed undercoolings. More recently, technical advances have enabled the study of magmas undergoing slow decompression at controlled rates. In these instances, undercooling is a variable, not a constant. Time-dependent changes in effective undercooling may generate complex textural or compositional variations as the relevant liquidus shifts and kinetically-favored phases compete for components. The challenge is to extract meaningful information from rocks that have experienced a time-integrated history of crystallization and vesiculation. To address this problem, we have performed a series of dynamic decompression experiments on a hydrous Mount St. Helens rhyodacite. Each sample was first equilibrated at conditions inferred for the shallow 1980 magma chamber (200 MPa and 880-900 °C), then isothermally decompressed at a constant rate (1-1000 MPa/hr). Charges quenched at different pressures yield syn-eruptive 'snapshots' of the decompressing system. We use these snapshots to assess how kinetics governs the stabilities of multiple phases (plagioclase, amphibole, orthopyroxene, and Fe-Ti oxides) as a function of depth and decompression rate. Our results can be qualitatively summarized by 'dynamic phase diagrams' that define the crystallizing phases in quench pressure-decompression rate space. Such diagrams are useful for two reasons: (1) they provide a means of relating observed rock textures to quench pressures and decompression rates for the simple case of continuous ascent, and (2) they identify the dominant crystallizing phases across a range of conditions. Our initial results show that, as in other silicic systems, plagioclase is often the principal crystallizing phase; however

  19. A new biophysical decompression model for estimating the risk of articular bends during and after decompression.

    PubMed

    Hugon, J; Rostain, J-C; Gardette, B

    2011-08-21

    The biophysical models that intend to predict the risk of decompression sickness after a change of pressure are not numerous. Few approaches focus in particular on joints as target tissues, with the aim to describe properly the mechanisms inducing pain. Nevertheless, for this type of decompression incidents, called articular bends, no model proved to fit the empirical results for a broad range of exposures and decompression procedures. We present here an original biophysical decompression model for describing the occurrence of articular bends. A target joint is broken down into two parts that exchange inert gases with the blood by perfusion and with each other by diffusion over distances of a few millimetres. This diffusion pathway allows the slow amplification of microbubbles growing during and after decompression, consistent with the possible delayed occurrence of bends. The diffusion coefficients introduced into this model are larger than those introduced into most modern decompression models. Their value remains physical (#10(-9)m(2)/s). Inert gas exchanges and the formation, amplification and resorption of microbubbles during and after decompression were simulated. We used a critical gas volume criterion for predicting the occurrence of bends. A risk database extracted from COMEX experience and other published studies were used for the correlation of model parameters not known a priori. We considered a large range of exposure, and the commonly used inert gases nitrogen and helium. This correlation phase identified the worst biophysical conformations most likely to lead to the formation, in tissues such as tendons, of a large number of microbubbles recruited from pre-existing gas nuclei during decompression. The risk of bends occurrence was found to be linked to the total separated gas volume generated during and after decompression. A clamping phenomenon occurs soon after the start of decompression, greatly slowing the gas exchanges controlled especially by

  20. Variability of raindrop size distributions and radar reflectivity-rain rate relations in extreme Mediterranean precipitation

    NASA Astrophysics Data System (ADS)

    Uijlenhoet, R.; Hazenberg, P.; Yu, N.; Boudevillain, B.; Delrieu, G.

    2010-12-01

    In radar hydrology the relationship between the reflectivity factor (Z) and the rainfall intensity (R) is generally assumed to follow a power law of which the parameters change both in space and time and depend on the drop size distribution (DSD). Based on disdrometer data, this study tries to improve our understanding of the temporal variability of the power-law relationship between Z and R using the scaling law formalism for the raindrop size distribution. In particular, this study focuses on the inter-event variability of Z-R coefficients and associated DSD-parameters and their relationship to the type of precipitation. This is crucial for developing improved quantitative precipitation estimation algorithms for extreme, flash-flood triggering rainfall. Within the DSD scaling-law framework a new normalized parameter estimation method is presented, which calculates significantly faster than the original method and leads to bulk event estimates of the DSD-parameters and associated Z-R coefficients. Based on a 2.5-year disdrometer dataset collected in the Cevennes-Vivarais region in the South of France, comprising a total of 70 events, it is shown that the quality of the resulting Z-R relationships obtained by the new method compares well to two standard least-squares fitting techniques. A major benefit of the new implementation, as compared to such purely statistical methods, is that it also provides information concerning the intrinsic properties of the DSD. For each of the 70 events this study also estimates the convective activity based on a threshold technique. Results show that convective events generally tend to have smaller Z-R exponents, which is expected to result from an increased amount of drop interaction. For stratiform events, a much larger range in exponents is obtained, which is expected to depend on differences in meteorological origin (snow vs. ice). For the types of precipitation events observed in the Cevennes region, for a given value of the

  1. Revealing rate-limiting steps in complex disease biology: The crucial importance of studying rare, extreme-phenotype families.

    PubMed

    Chakravarti, Aravinda; Turner, Tychele N

    2016-06-01

    The major challenge in complex disease genetics is to understand the fundamental features of this complexity and why functional alterations at multiple independent genes conspire to lead to an abnormal phenotype. We hypothesize that the various genes involved are all functionally united through gene regulatory networks (GRN), and that mutant phenotypes arise from the consequent perturbation of one or more rate-limiting steps that affect the function of the entire GRN. Understanding a complex phenotype thus entails unraveling the details of each GRN, namely, the transcription factors that bind to cis regulatory elements affected by sequence variants altering transcription of specific genes, and their mutual feedback relationships. These GRNs can be identified through their rate-limiting steps and are best uncovered by genomic analyses of rare, extreme phenotype families, thus providing a coherent molecular basis to complex traits and disorders. PMID:27062178

  2. Very high speed optoelectronic functions for extremely high data rate communications between satellites

    NASA Astrophysics Data System (ADS)

    Folcke, Georges; Defrancq, Jean-Marc; Geffroy, Dominique; Roy, Bernard

    1998-05-01

    High data rate communications between satellites request to develop very specific electronic circuits. Very high speed, high current (more than 500 mA peak to peak) and low power consumption laser driver was realized and integrated into a specific low volume and low mass hybrid design. This paper reports also the realization of a complete receiver based on the integration of an Avalanche Photodiode (APD) into a very low noise preamplifier followed by an other hybrid module including a limiter amplifier, a clock recovery and decision circuit. The high voltage DC/DC convertor for the APD is also presented as a third hybrid circuit. Full bit rate is in the range of 622 Mbps. For the receiver, the sensitivity obtained is very closed to the theoretical possibilities. The opto- electronic modules under realization (or realized) are fiber pigtailed, with a single mode fiber on the transmitter side and a multimode fiber on the receiver side which allow their integration into the communication boxes. The present paper gives an overview of the modules development, including the main results, and situates these activities in a more complete realization of optical communication boxes.

  3. [Emergency treatment in decompression accidents in shipyards].

    PubMed

    Comet, M

    1989-08-01

    The Comex company has underwater workplaces scattered over the whole world, which are therefore very often far away from a medical center equipped for the treatment of decompression sickness. However, the subsequent evolution of such an event depends mainly on how fast the first aid is given to the patient. Therefore, the scientific and medical departments of our company developed a medical handbook to be used by chiefs of working platforms. The text which has to be easily understandable, mentions: a cursory description of the clinical signs of the different decompression accidents the measures which have to be taken in each case, depending on: the moment of the emergency: after or during decompression, the presence of an insufficient decompression, or a "blow-up". The handbook contains several recompression tables, first aid treatment recommendations and drugs. It has to be stressed that these procedures are only emergency steps. They should be performed before the patient can be transferred to a medical center with expertise in the treatment of decompression accidents. PMID:2799360

  4. [Decompression illness: minor symptoms, major consequences].

    PubMed

    Gho, J M I H Ing Han; Kramer, Irene Fleur; van Hulst, Rob A; Kramer, William L M

    2012-01-01

    Nowadays, diving is being performed ever more frequently; it is thus important to take diving injuries into consideration in patients presenting with even minor complaints after diving. Every dive is risky and could result in decompression illness, barotrauma and/or death. We report on two cases of decompression illness: a 30-year old man, an occupational diver, and a 46-year old man, an experienced diver, who were both clinically suspected of having decompression illness and were treated with hyperbaric oxygen in a recompression chamber. Both were eventually symptom-free after several treatments. Decompression illness is caused by a reduction in ambient pressure, which results in intra- or extravascular bubbles. Symptoms vary and are dependent on the site affected: from minor pain to neurological symptoms and death. If patients are suspected of having diving injuries, we recommend contacting a centre specialised in diving and hyperbaric medicine. Recompression in a hyperbaric chamber is the definitive treatment for decompression illness and should be performed as soon as possible. PMID:22951132

  5. Effect of gender and stroke rate on joint power characteristics of the upper extremity during simulated rowing.

    PubMed

    Attenborough, Alison S; Smith, Richard M; Sinclair, Peter J

    2012-01-01

    Males typically have greater upper body strength than do females, which is likely to impact on the rowing techniques adopted by each sex. The aim of this study was to quantify energy contributions and compare the joint power production of upper extremity joints between the sexes. Seven males and eight females performed 60 s trials at five different stroke rates. External forces were measured at the handle and stretcher, while kinematics were recorded by motion analysis. Joint moments were derived by inverse dynamic calculations, followed by the calculation of joint powers and gross mechanical energy expenditure. Male rowers expended more total external energy per stroke and made a larger percentage contribution of angular shoulder energy to their total external energy expenditure. As stroke rate increased, the contribution from elbow and angular shoulder energy contributions decreased for both males and females. Female rowers decreased their angular shoulder contribution at a slower rate than did males as stroke rate increased. The overall percentage of work done on the stretcher was higher for male rowers, and this difference further increased at higher stroke rates. The results of this study suggest that specific upper body conditioning may be particularly important for female rowers. PMID:22296106

  6. The distribution of Extremely High Accretion Rates and Metallicities of QSO's as a Function of Redshift over Cosmic Evolution

    NASA Astrophysics Data System (ADS)

    Abu Seif, Nasser; Kazanas, Demosthenes

    2016-07-01

    The investigation of how QSOs' extremity of accretion rates vary with redshift has remained a major focus of our study in the last five years. How does the evolution of QSOs trace the accretion history of early SMBH? What does accretion at super-Eddington rates look like? Does the correlation between SMBHs and metallicity of QSOs emission line evolve differently at high redshift? Is it a surprise that metallicity is high at high redshift, or is this expected? Here, we establish a new database for the width of an emission line (e.g., Hβ, Mg II and C IV) to obtain a large statistical sample of QSOs at different redshifts. We calculated L/LEdd that determined mass from previous studies (Sloan Digital Sky Survey (SDSS)). We investigated the significant evolution of L/ LEdd for any value of MBH as a function of redshift. Also, we investigated the evolution and distribution of the accretion rate (L/LEdd) over cosmic time with a concentration on the extremely high accretion rate sources at high redshift. The current study investigated the accretion rate (L/LEdd) correlation to other QSO properties and investigated how the accretion of Black Holes L/LEdd and MBH occurs within heavily obscured environments. Our research found that some QSOs are radiating near the Eddington limit with L/ Ledd ~ 1 and those QSOs have extreme accretion. We also found that the lowest M BH has the highest accretion rate, a result that was already noted by McClure & Dunlop (2004). The distribution of Eddington ratio displayed by QSOs clearly shows that all luminous QSOs accreted at their Eddington limit have a poor approximation. This result is important because it is often assumed that optically luminous QSOs are accreting at their Eddington limit within the models of QSOs evolution. We determined the peak of the L/LEdd versus redshift and we found the largest of those peaks to be at the interval of redshift (1< Z < 2). We noted that the highest peak of the distribution of L/LEdd at all

  7. Heart rate variability and arterial oxygen saturation response during extreme normobaric hypoxia.

    PubMed

    Botek, Michal; Krejčí, Jakub; De Smet, Stefan; Gába, Aleš; McKune, Andrew J

    2015-07-01

    The primary purpose of this study was to assess the response of autonomic cardiac activity and changes in the arterial oxygen saturation (SpO2) during normobaric hypoxia and subsequent recovery. Heart rate variability (HRV) and SpO2 were monitored in a supine position during hypoxia (FiO2=9.6%) for 10min, and normoxic recovery in 29 subjects. Spectral analysis of HRV quantified the autonomic cardiac activity by means of low frequency (LF) (0.05-0.15Hz) and high frequency (HF) (0.15-0.50Hz) power transformed by natural logarithm (Ln). Based on the SpO2 response to hypoxia, the subjects were divided into Resistant (RG, SpO2=80.8±7.0%) or Sensitive (SG, SpO2=67.2±2.9%) group. The SpO2 and vagal activity (LnHF) significantly decreased during hypoxia in both groups. A withdrawal in vagal activity was significantly greater in SG compared to RG. Moreover, only in SG, a relative increase in sympathetic modulation (Ln LF/HF) during hypoxia occurred. Correlations (r=-0.461, and r=0.595, both P<0.05) between ΔSpO2 (delta) and ΔLn LF/HF, and ΔLnHF were found. Based on results, it seems that SpO2 level could be an important factor that influences the autonomic cardiac response in hypoxia. PMID:25907329

  8. Extremely low long-term erosion rates around the Gamburtsev Mountains in interior East Antarctica

    NASA Astrophysics Data System (ADS)

    Cox, S. E.; Thomson, S. N.; Reiners, P. W.; Hemming, S. R.; van de Flierdt, T.

    2010-11-01

    The high elevation and rugged relief (>3 km) of the Gamburtsev Subglacial Mountains (GSM) have long been considered enigmatic. Orogenesis normally occurs near plate boundaries, not cratonic interiors, and large-scale tectonic activity last occurred in East Antarctica during the Pan-African (480-600 Ma). We sampled detrital apatite from Eocene sands in Prydz Bay at the terminus of the Lambert Graben, which drained a large pre-glacial basin including the northern Gamburtsev Mountains. Apatite fission-track and (U-Th)/He cooling ages constrain bedrock erosion rates throughout the catchment. We double-dated apatites to resolve individual cooling histories. Erosion was very slow, averaging 0.01-0.02 km/Myr for >250 Myr, supporting the preservation of high elevation in interior East Antarctica since at least the cessation of Permian rifting. Long-term topographic preservation lends credence to postulated high-elevation mountain ice caps in East Antarctica since at least the Cretaceous and to the idea that cold-based glaciation can preserve tectonically inactive topography.

  9. Threading polyintercalators with extremely slow dissociation rates and extended DNA binding sites

    PubMed Central

    Smith, Amy Rhoden; Iverson, Brent L.

    2013-01-01

    The development of small molecules that bind DNA sequence specifically has the potential to modulate gene expression in a general way. One mode of DNA binding is intercalation, or the insertion of molecules between DNA base pairs. We have developed a modular polyintercalation system in which intercalating naphthalene diimide (NDI) units are connected by flexible linkers that alternate between the minor and major grooves of DNA when bound. We recently reported a threading tetraintercalator with a dissociation half-life of 16 days, the longest reported to date, from its preferred 14 bp binding site. Herein, three new tetraintercalator derivatives were synthesized with one, two, and three additional methylene units in the central major groove-binding linker. These molecules displayed dissociation half-lives of 57, 27, and 18 days, respectively, from the 14 bp site. The optimal major groove-binding linker was used in the design of an NDI hexaintercalator that was analyzed by gel-shift assays, DNase I footprinting, and UV-visible spectroscopy. The hexaintercalator bound its entire 22 bp binding site, the longest reported specific binding site for a synthetic, non-nucleic acid based DNA binding molecule, but with a significantly faster dissociation rate compared to the tetraintercalators. PMID:23919778

  10. Threading polyintercalators with extremely slow dissociation rates and extended DNA binding sites.

    PubMed

    Rhoden Smith, Amy; Iverson, Brent L

    2013-08-28

    The development of small molecules that bind DNA sequence specifically has the potential to modulate gene expression in a general way. One mode of DNA binding is intercalation, or the insertion of molecules between DNA base pairs. We have developed a modular polyintercalation system in which intercalating naphthalene diimide (NDI) units are connected by flexible linkers that alternate between the minor and major grooves of DNA when bound. We recently reported a threading tetraintercalator with a dissociation half-life of 16 days, the longest reported to date, from its preferred 14 bp binding site. Herein, three new tetraintercalator derivatives were synthesized with one, two, and three additional methylene units in the central major groove-binding linker. These molecules displayed dissociation half-lives of 57, 27, and 18 days, respectively, from the 14 bp site. The optimal major groove-binding linker was used in the design of an NDI hexaintercalator that was analyzed by gel-shift assays, DNase I footprinting, and UV-vis spectroscopy. The hexaintercalator bound its entire 22 bp binding site, the longest reported specific binding site for a synthetic, non-nucleic acid-based DNA binding molecule, but with a significantly faster dissociation rate compared to the tetraintercalators. PMID:23919778

  11. Extremely Low Bit-Rate Nearest Neighbor Search Using a Set Compression Tree.

    PubMed

    Arandjelović, Relja; Zisserman, Andrew

    2014-12-01

    The goal of this work is a data structure to support approximate nearest neighbor search on very large scale sets of vector descriptors. The criteria we wish to optimize are: (i) that the memory footprint of the representation should be very small (so that it fits into main memory); and (ii) that the approximation of the original vectors should be accurate. We introduce a novel encoding method, named a Set Compression Tree (SCT), that satisfies these criteria. It is able to accurately compress 1 million descriptors using only a few bits per descriptor. The large compression rate is achieved by not compressing on a per-descriptor basis, but instead by compressing the set of descriptors jointly. We describe the encoding, decoding and use for nearest neighbor search, all of which are quite straightforward to implement. The method, tested on standard benchmarks (SIFT1M and 80 Million Tiny Images), achieves superior performance to a number of state-of-the-art approaches, including Product Quantization, Locality Sensitive Hashing, Spectral Hashing, and Iterative Quantization. For example, SCT has a lower error using 5 bits than any of the other approaches, even when they use 16 or more bits per descriptor. We also include a comparison of all the above methods on the standard benchmarks. PMID:26353147

  12. Acute kidney injury due to decompression illness.

    PubMed

    Viecelli, Andrea; Jamboti, Jagadish; Waring, Andrew; Banham, Neil; Ferrari, Paolo

    2014-08-01

    Decompression illness is a rare but serious complication of diving caused by intravascular or extravascular gas bubble formation. We report the first case of acute kidney injury in a 27-year-old diver following three rapid ascents. He presented with transient neurological symptoms and abdominal pain followed by rapidly progressive acute kidney injury (creatinine peak 1210 µmol/L) due to arterial air emboli. He received supportive care and 100% oxygen followed by hyperbaric therapy and recovered fully. Arterial air emboli caused by rapid decompression can affect multiple organs including the kidneys. Early transfer to a hyperbaric unit is important as complications may present delayed. PMID:25852912

  13. Hypobaric decompression prebreathe requirements and breathing environment

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Pilmanis, Andrew A.

    1993-01-01

    To reduce incidence of decompression sickness (DCS), prebreathing 100 percent oxygen to denitrogenate is required prior to hypobaric decompressions from a sea level pressure breathing environment to pressures lower than 350 mm Hg (20,000 ft; 6.8 psia). The tissue ratio (TR) of such exposures equals or exceeds 1.7; TR being the tissue nitrogen pressure prior to decompression divided by the total pressure after decompression (((0.781)(14.697))/6.758). Designing pressure suits capable of greater pressure differentials, lower TR's, and procedures which limit the potential for DCS occurrence would enhance operational efficiency. The current 10.2 psia stage decompression prior to extravehicular activity (EVA) from the Shuttle in the 100 percent oxygen, 4.3 psia suit, results in a TR of 1.65 and has proven to be relatively free of DCS. Our recent study of zero-prebreathe decompressions to 6.8 psia breathing 100 percent oxygen (TR = 1.66) also resulted in no DCS (N = 10). The level of severe, Spencer Grades 3 or 4, venous gas emboli (VGE) increased from 0 percent at 9.5 psia to 40 percent at 6.8 psia yielding a Probit curve of VGE risk for the 51 male subjects who participated in these recent studies. Earlier, analogous decompressions using a 50 percent oxygen, 50 percent nitrogen breathing mixture resulted in one case of DCS and significantly higher levels of severe VGE, e.g., at 7.8 psia, the mixed gas breathing environment resulted in a 56 percent incidence of severe VGE versus 10 percent with use of 100 percent oxygen. The report of this study recommended use of 100 percent oxygen during zero-prebreathe exposure to 6.8 psia if such a suit could be developed. For future, long-term missions, we suggest study of the effects of decompression over several days to a breathing environment of 150 mmHg O2 and approximately 52 mmHg He as a means of eliminating DCS and VGE hazards during subsequent excursions. Once physiologically adapted to a 4 psia vehicle, base, or space

  14. Acute kidney injury due to decompression illness

    PubMed Central

    Viecelli, Andrea; Jamboti, Jagadish; Waring, Andrew; Banham, Neil; Ferrari, Paolo

    2014-01-01

    Decompression illness is a rare but serious complication of diving caused by intravascular or extravascular gas bubble formation. We report the first case of acute kidney injury in a 27-year-old diver following three rapid ascents. He presented with transient neurological symptoms and abdominal pain followed by rapidly progressive acute kidney injury (creatinine peak 1210 µmol/L) due to arterial air emboli. He received supportive care and 100% oxygen followed by hyperbaric therapy and recovered fully. Arterial air emboli caused by rapid decompression can affect multiple organs including the kidneys. Early transfer to a hyperbaric unit is important as complications may present delayed. PMID:25852912

  15. Evidence Report: Risk of Decompression Sickness (DCS)

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Norcross, Jason R.; Wessel, James H. III; Abercromby, Andrew F. J.; Klein, Jill S.; Dervay, Joseph P.; Gernhardt, Michael L.

    2013-01-01

    The Risk of Decompression Sickness (DCS) is identified by the NASA Human Research Program (HRP) as a recognized risk to human health and performance in space, as defined in the HRP Program Requirements Document (PRD). This Evidence Report provides a summary of the evidence that has been used to identify and characterize this risk. Given that tissue inert gas partial pressure is often greater than ambient pressure during phases of a mission, primarily during extravehicular activity (EVA), there is a possibility that decompression sickness may occur.

  16. Extreme soil erosion rates in citrus slope plantations and control strategies. A literature review

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Ángel González Peñaloza, Félix; Pereira, Paulo; Reyes Ruiz Gallardo, José; García Orenes, Fuensanta; Burguet, María

    2013-04-01

    Soil Erosion is a natural process that shapes the Earth. Due to the impact of agriculture, soil erosion rates increase, landforms show gullies and rills, and soils are depleted. In the Mediterranean, wheat, olive and vineyards were the main agriculture products, but new plantations are being found in sloping terrain due to the drip-irrigation. This new strategy results in the removal of the traditional terraces in order to make suitable for mechanization the agriculture plantation. Citrus is a clear example of the impact of the new chemical agriculture with a high investment in herbicides, pesticides, mechanisation, land levelling and drip computer controlled irrigation systems. The new plantation of citrus orchards is found in the Mediterranean, but also in California, Florida, China and Brazil. Chile, Argentina, and South Africa are other producers that are moving to an industrial production of citrus. This paper shows how the citrus plantations are found as one of the most aggressive plantation due to the increase in soil erosion, and how we can apply successful control strategies. The research into the high erosion rates of citrus orchard built on the slopes are mainly found in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012) and in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) Most of the research done devoted to the measurements of the soil losses but also some research is done related to the soil properties (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012) and the impact of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel in order to reduce the soil losses. There are 116 million tonnes of citrus produced yearly, and this affects a large surface of the best land. The citrus orchards are moving from flood irrigated to drip

  17. Extreme soil erosion rates in citrus slope plantations and control strategies. A literature review

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Ángel González Peñaloza, Félix; Pereira, Paulo; Reyes Ruiz Gallardo, José; García Orenes, Fuensanta; Burguet, María

    2013-04-01

    Soil Erosion is a natural process that shapes the Earth. Due to the impact of agriculture, soil erosion rates increase, landforms show gullies and rills, and soils are depleted. In the Mediterranean, wheat, olive and vineyards were the main agriculture products, but new plantations are being found in sloping terrain due to the drip-irrigation. This new strategy results in the removal of the traditional terraces in order to make suitable for mechanization the agriculture plantation. Citrus is a clear example of the impact of the new chemical agriculture with a high investment in herbicides, pesticides, mechanisation, land levelling and drip computer controlled irrigation systems. The new plantation of citrus orchards is found in the Mediterranean, but also in California, Florida, China and Brazil. Chile, Argentina, and South Africa are other producers that are moving to an industrial production of citrus. This paper shows how the citrus plantations are found as one of the most aggressive plantation due to the increase in soil erosion, and how we can apply successful control strategies. The research into the high erosion rates of citrus orchard built on the slopes are mainly found in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012) and in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) Most of the research done devoted to the measurements of the soil losses but also some research is done related to the soil properties (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012) and the impact of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel in order to reduce the soil losses. There are 116 million tonnes of citrus produced yearly, and this affects a large surface of the best land. The citrus orchards are moving from flood irrigated to drip

  18. Decompression sickness following breath-hold diving.

    PubMed

    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  19. Effect of syneruptive decompression path on shifting intensity in basaltic sub-Plinian eruption: Implication of microlites in Yufune-2 scoria from Fuji volcano, Japan

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuki; Fujii, Toshitsugu

    2010-12-01

    To constrain the timing and conditions of syneruptive magma ascent that are responsible for shifting eruption intensity, we have investigated a basaltic sub-Plinian eruption that produced Yufune-2 scoria in Fuji volcano 2200 years ago. We deduced magmatic decompression conditions from groundmass microlite textures, including decompression path (i.e. evolution in decompression rate) and approximate decompression rate, in order to relate them to eruption intensity. The microlites revealed decompression conditions after water saturation at 700-1100 m depth. The temporal change in scoria size indicates that the magma discharge rate and resultant eruption intensity increased from unit a to unit b, and then declined toward ending units d and e. The overall decompression rate in each eruptive unit has a positive correlation with eruption intensity. The variation in decompression rate was enlarged in the final units, where the maximum remained the same as the peak through the eruption (0.13-0.22 MPa/s for units b and c), while the minimum was 0.025 MPa/s. The large variation here is due to 1) variation in flow velocity across conduit and 2) part of the erupted magma in unit d experienced remarkably slow decompression (0.002-0.003 MPa/s) resulting from decreased overpressure in the reservoir following the major eruption of unit b. Furthermore, crystal size distribution (CSD) of microlites implied that the earliest erupted magma (unit a) had once been decompressed slowly (0.005-0.012 MPa/s), having been arrested by material in the conduit-vent system, which was followed by an increase in decompression rate due to removal of the material at the initiation of the eruption. In addition, the magma that had been ascending slowly before the unit-d eruption may record the increase in decompression rate. This increased rate resulted from being pushed up by the successive magma at the start of that eruption. Two factors had a major impact on eruption intensity. First, magma

  20. Severe neurological decompression sickness in a U-2 pilot.

    PubMed

    Jersey, Sean L; Baril, Robert T; McCarty, Richmond D; Millhouse, Christina M

    2010-01-01

    Severe neurological decompression sickness (DCS) has been a rare entity in the U.S. Air Force, including the U-2 community. In over 50 yr of operation, few U-2 pilots reported severe neurological DCS in flight despite the extreme altitudes at which they operate. This article describes a near-fatal case of neurological DCS that occurred during a combat mission. The injury left the pilot with permanent cognitive deficits that correlated with focal lesions present on magnetic resonance imaging of his brain. To our knowledge, the images presented herein are the first to show radiological evidence of brain injury induced by altitude DCS. Though only a single case, the objective and clinical findings in the case pilot are similar to results documented in divers suffering DCS with central nervous system injury and victims of traumatic brain injury. DCS will remain a potentially serious threat to current and future air and space operations. PMID:20058739

  1. The biophysical and physiological basis for mitigated elevations in heart rate with electric fan use in extreme heat and humidity

    NASA Astrophysics Data System (ADS)

    Ravanelli, Nicholas M.; Gagnon, Daniel; Hodder, Simon G.; Havenith, George; Jay, Ollie

    2016-07-01

    Electric fan use in extreme heat wave conditions has been thought to be disadvantageous because it might accelerate heat gain to the body via convection. However, it has been recently shown that fan use delays increases in heart rate even at high temperatures (42 °C) in young adults. We here assess the biophysical and physiological mechanisms underlying the apparently beneficial effects of fan use. Eight males (24 ± 3 y; 80.7 ± 11.7 kg; 2.0 ± 0.1 m2) rested at either 36 °C or 42 °C, with (F) or without (NF) electric fan use (4.2 m/s) for 120 min while humidity increased every 7.5 min by 0.3 kPa from a baseline value of 1.6 kPa. Heart rate (HR), local sweat rate (LSR), cutaneous vascular conductance (CVC), core and mean skin temperatures, and the combined convective/radiative heat loss (C+R), evaporative heat balance requirements (Ereq) and maximum evaporative potential (Emax) were assessed. C+R was greater with fan use at 36 °C (F 8 ± 6, NF 2 ± 2 W/m2; P = 0.04) and more negative (greater dry heat gain) with fan use at 42 °C (F -78 ± 4, NF -27 ± 2 W/m2; P < 0.01). Consequently, Ereq was lower at 36 °C (F 38 ± 16, NF 45 ± 3 W/m2; P = 0.04) and greater at 42 °C (F 125 ± 1, NF 74 ± 3 W/m2; P < 0.01) with fan use. However, fan use resulted in a greater Emax at baseline humidity at both 36 °C (F 343 ± 10, NF 153 ± 5 W/m2; P < 0.01) and 42 °C (F 376 ± 13, NF 161 ± 4 W/m2; P < 0.01) and throughout the incremental increases in humidity. Within the humidity range that a rise in HR was prevented by fan use but not without a fan, LSR was higher in NF at both 36 °C (P = 0.04) and 42 °C (P = 0.05), and skin temperature was higher in NF at 42 °C (P = 0.05), but no differences in CVC or core temperatures were observed (all P > 0.05). These results suggest that the delayed increase in heart rate with fan use during extreme heat and humidity is associated with improved evaporative efficiency.

  2. Microsurgical endonasal decompression in dysthyroid orbitopathy.

    PubMed

    May, A; Fries, U; Reimold, I; Weber, A

    1999-01-01

    Diagnosis of thyroid eye disease can be established by its history, signs, symptoms, clinical and laboratory findings of an autoimmune thyroid disease. Therapy for this disease is limited to a few options, which should be administered depending on its stage and inflammatory activity. When medication and radiation therapy fail indications for decompression are: loss of visual acuity or visual field defects, increasing strabism and severe keratopathy due to eyelid retraction. Numerous surgical decompression techniques have been described in endocrine orbitopathy. We have adopted endonasal microsurgery, because this technique gives the freedom to work bimanually, ensures a stereomicoscopic view of the intranasal landmarks of orbital walls and allows simultaneous decompression of the medial and inferior orbital wall as well as a good relief of pressure at the orbital apex. Decompressions were performed on 27 orbits in 17 patients, via the endonasal microsurgical, 3 via external approach. The microscopic approach was entirely comparable with regard to reduction of proptosis with a mean improvement of 4.1 mm against a mean of 4.7 mm by external approach and a mean 0.2 of better visual acuity in both procedures. The microsurgical technique is considered superior to an external approach avoiding external scars, neural pains and reportedly less diplopia. Also, trauma to the nalolacrimal and nasofrontal ducts are avoided. The healing phase and the hospitalization time is shorter. PMID:10687942

  3. Long arm decompression osteotomy for hallux limitus.

    PubMed

    Robinson, Stephen C; Frank, Ryan P

    2005-04-01

    This article presents a new osteotomy for stage I or II hallux limitus. The long arm decompression osteotomy can be used to shorten and plantarflex the first metatarsal. The indications, surgical technique, advantages, and disadvantages are described in detail. PMID:15833423

  4. The Effect of Extremely Low Frequency Pulsed Electromagnetic Field on In Vitro Fertilization Success Rate in N MRI Mice

    PubMed Central

    Hafizi, Leili; Sazgarnia, Ameneh; Mousavifar, Nezhat; Karimi, Mohammad; Ghorbani, Saleh; Kazemi, Mohammad Reza; Emami Meibodi, Neda; Hosseini, Golkoo; Mostafavi Toroghi, Hesam

    2014-01-01

    Objective: The effects of exposure to electromagnetic fields (EMF) on reproduction systems have been widely debated. In this study, we aimed to investigate whether low frequency EMF could ameliorate the in vitro fertilization success rate in Naval medical research institute (NMRI) Mice. Materials and Methods: In this randomized comparative animal study, ten NMRI mice were randomly divided into 2 equal groups (control and experimental). 10 IU of human chorionic gonadotropin (hCG) was injected intraperitoneally to both groups in order to stimulate ovulating, and ovums were then aspirated and kept in KSOM (modified version of sequential simplex optimization medium with a higher K+ concentration) culture medium. Metaphase II ovums were separated, and sperms obtained by "swim out" method were added to metaphase II ovums in the culture medium. The experimental group was exposed to 1.3 millitesla pulsed electromagnetic field at 4 kilohertz frequency for 5 hours. To assess the efficacy, we considered the identification of two-pronuclear zygote (2PN) under microscope as fertilizing criterion. Results: Total number of collected ovums in the control and experimental groups was 191 and 173, respectively, from which 58 (30.05%) and 52 (30.36%) ovums were collected from metaphase II, respectively. In vitro fertilization (IVF) success rate was 77% in extremely low frequency- pulsed electromagnetic field (ELFPEMF) for exposed group (experimental), whereas the rate was 68% for control group. Conclusion: Despite increased percentile of IVF success rate in exposed group, there was no statistically significant difference between 2 groups, but this hypothesis has still been stated as a question. Further studies with larger sample sizes and different EMF designs are suggested. PMID:24381855

  5. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    SciTech Connect

    Hufnagel, Todd C.

    2014-06-09

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  6. Pictorial essay: Role of ultrasound in failed carpal tunnel decompression

    PubMed Central

    Botchu, Rajesh; Khan, Aman; Jeyapalan, Kanagaratnam

    2012-01-01

    USG has been used for the diagnosis of carpal tunnel syndrome. Scarring and incomplete decompression are the main causes for persistence or recurrence of symptoms. We performed a retrospective study to assess the role of ultrasound in failed carpal tunnel decompression. Of 422 USG studies of the wrist performed at our center over the last 5 years, 14 were for failed carpal tunnel decompression. Scarring was noted in three patients, incomplete decompression in two patients, synovitis in one patient, and an anomalous muscle belly in one patient. No abnormality was detected in seven patients. We present a pictorial review of USG findings in failed carpal tunnel decompression. PMID:22623813

  7. Where are We Now with Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction?

    PubMed Central

    Hwang, Jeong-Hyun

    2013-01-01

    In spite of the best medical treatment, large hemispheric infarction, resulting from acute occlusion of either the internal carotid or the proximal middle cerebral artery with insufficient collateral blood flow is associated with a high case fatality rate of approximately 60%. Thus, a decompressive hemicraniectomy is considered a life-saving procedure for this devastating disease. Findings of three recent randomized, controlled clinical trials and their meta-analysis showed that early surgical decompression not only reduced the number of case fatalities but also increased the incidence of favorable outcomes. The authors review the pathophysiology, historical background in previous studies, operative timing, surgical technique and clinical outcomes of surgical decompression for malignant hemispheric infarction. PMID:23844349

  8. Diving decompression models and bubble metrics: modern computer syntheses.

    PubMed

    Wienke, B R

    2009-04-01

    A quantitative summary of computer models in diving applications is presented, underscoring dual phase dynamics and quantifying metrics in tissue and blood. Algorithms covered include the multitissue, diffusion, split phase gradient, linear-exponential, asymmetric tissue, thermodynamic, varying permeability, reduced gradient bubble, tissue bubble diffusion, and linear-exponential phase models. Defining relationships are listed, and diver staging regimens are underscored. Implementations, diving sectors, and correlations are indicated for models with a history of widespread acceptance, utilization, and safe application across recreational, scientific, military, research, and technical communities. Presently, all models are incomplete, but many (included above) are useful, having resulted in diving tables, underwater meters, and dive planning software. Those herein employ varying degrees of calibration and data tuning. We discuss bubble metrics in tissue and blood as a backdrop against computer models. The past 15 years, or so, have witnessed changes and additions to diving protocols and table procedures, such as shorter nonstop time limits, slower ascent rates, shallow safety stops, ascending repetitive profiles, deep decompression stops, helium based breathing mixtures, permissible reverse profiles, multilevel techniques, both faster and slower controlling repetitive tissue halftimes, smaller critical tensions, longer flying-after-diving surface intervals, and others. Stimulated by Doppler and imaging technology, table and decompression meter development, theory, statistics, chamber and animal testing, or safer diving consensus, these modifications affect a gamut of activity, spanning bounce to decompression, single to multiday, and air to mixed gas diving. As it turns out, there is growing support for many protocols on operational, experimental, and theoretical grounds, with bubble models addressing many concerns on plausible bases, but with further testing or

  9. Decompression without Fusion for Low-Grade Degenerative Spondylolisthesis

    PubMed Central

    Cheung, Jason Pui Yin; Cheung, Prudence Wing Hang; Cheung, Kenneth Man Chee

    2016-01-01

    Study Design Retrospective series. Purpose Assess results of decompression-only surgery for low-grade degenerative spondylolisthesis with consideration of instability. Overview of Literature There is no consensus on whether fusion or decompression-only surgery leads to better outcomes for patients with low-grade degenerative spondylolisthesis. Current trends support fusion but many studies are flawed due to over-generalization without consideration of radiological instability and their variable presentations and natural history. Methods Patients with surgically treated degenerative spondylolisthesis from 1990–2013 were included. Clinical and radiological instability measures were included. Any residual or recurrence of symptoms, revision surgery performed and functional outcome scores including the numerical global rate of change scale, visual analogue scale, and modified Barthel index were measured. Follow-up periods for patients were divided into short-term (<5 years), mid-term (5–10 years) and long-term (>10 years). Results A total of 64 patients were recruited. Mechanical low back pain was noted in 48 patients and most (85.4%) had relief of back pain postoperatively. Radiological instability was noted in 4 subjects by flexion-extension radiographs and 12 subjects with prone traction radiographs by increased disc height and reduction of olisthesis and slip angle. From the results of the short-term, mid-term and long-term follow-up, reoperation only occurred within the first 5-year follow-up period. All functional scores improved from preoperative to postoperative 1-year follow-up. Conclusions Decompression-only for low-grade degenerative spondylolisthesis has good long-term results despite instability. Further higher-level studies should be performed on this patient group with radiological instability to suggest the superior surgical option. PMID:26949462

  10. THE LONG-TERM DECAY IN PRODUCTION RATES FOLLOWING THE EXTREME OUTBURST OF COMET 17P/HOLMES

    SciTech Connect

    Schleicher, David G.

    2009-10-15

    Numerous sets of narrowband filter photometry were obtained of Comet 17P/Holmes from Lowell Observatory during the interval of 2007 November 1 to 2008 March 5. Observations began 8 days following its extreme outburst, at which time the derived water production rate, based on OH measurements, was 5 x 10{sup 29} molecule s{sup -1} and the derived proxy of dust production, A({theta})f{rho}, was about 5 x 10{sup 5} cm. Relative production rates for the other gas species, CN, C{sub 2}, C{sub 3}, and NH, are consistent with 'typical' composition (based on our update to the classifications by A'Hearn et al.). An exponential decay in the logarithm of measured production rates as a function of time was observed for all species, with each species dropping by factors of about 200-500 after 125 days. All gas species exhibited clear trends with aperture size, and these trends are consistent with larger apertures having a greater proportion of older material that was released when production rates were higher. Much larger aperture trends were measured for the dust, most likely because the dust grains have smaller outflow velocities and longer lifetimes than the gas species; therefore, a greater proportion of older, i.e., higher production dust is contained within a given aperture. By extrapolating to a sufficiently small aperture size, we derive near-instantaneous water and dust production rates throughout the interval of observation, and also estimate values immediately following the outburst. The finite lifetime of the gas species requires that much higher ice vaporization rates were taking place throughout the observation interval than occurred prior to the outburst, likely due to the continued release of icy grains from the nucleus. The relatively small aperture trends for the gas species also imply that the bulk of fresh, excess volatiles are confined to the nucleus and near-nucleus regime, rather than being associated with the outburst ejecta cloud. A minimum of about 0

  11. Telemetry pill versus rectal and esophageal temperature during extreme rates of exercise-induced core temperature change.

    PubMed

    Teunissen, L P J; de Haan, A; de Koning, J J; Daanen, H A M

    2012-06-01

    Core temperature measurement with an ingestible telemetry pill has been scarcely investigated during extreme rates of temperature change, induced by short high-intensity exercise in the heat. Therefore, nine participants performed a protocol of rest, (sub)maximal cycling and recovery at 30 °C. The pill temperature (T(pill)) was compared with the rectal temperature (T(re)) and esophageal temperature (T(es)). T(pill) corresponded well to T(re) during the entire trial, but deviated considerably from T(es) during the exercise and recovery periods. During maximal exercise, the average ΔT(pill)-T(re) and ΔT(pill)-T(es) were 0.13 ± 0.26 and -0.57 ± 0.53 °C, respectively. The response time from the start of exercise, the rate of change during exercise and the peak temperature were similar for T(pill) and T(re.) T(es) responded 5 min earlier, increased more than twice as fast and its peak value was 0.42 ± 0.46 °C higher than T(pill). In conclusion, also during considerable temperature changes at a very high rate, T(pill) is still a representative of T(re). The extent of the deviation in the pattern and peak values between T(pill) and T(es) (up to >1 °C) strengthens the assumption that T(pill) is unsuited to evaluate central blood temperature when body temperatures change rapidly. PMID:22551669

  12. Ambulation Increases Decompression Sickness in Altitude Exposure

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Pollock, N. W.; Natoli, M. J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    INTRODUCTION - Exercise accelerates inert gas elimination during oxygen breathing prior to decompression (prebreathe), but may also promote bubble formation and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of exercise are likely critical to the net effect. The NASA Prebreathe Reduction Program (PRP) combined oxygen prebreathe and exercise preceding a 4.3 psi exposure in non-ambulatory subjects (a microgravity analog) to produce two protocols now used by astronauts preparing for extravehicular activity (CEVIS and ISLE). Additional work is required to investigate whether exercise normal to 1 G environments increases the risk of DCS over microgravity simulation. METHODS - The CEVIS protocol was replicated with one exception. Our subjects completed controlled ambulation (walking in place with fixed cadence and step height) during both preflight and at 4.3 psi instead of remaining non-ambulatory throughout. Decompression stress was graded with aural Doppler (Spencer 0-IV scale). Two-dimensional echocardiographic imaging was used to look for left heart gas emboli (the presence of which prompted test termination). Venous blood was collected at three points to correlate Doppler measures of decompression stress with microparticle (cell fragment) accumulation. Fisher Exact Tests compared test and control groups. Trial suspension would occur when DCS risk >15% or grade IV venous gas emboli (VGE) risk >20% (at 70% confidence). RESULTS - Eleven person-trials were completed (9 male, 2 female) when DCS prompted suspension. DCS was greater than in CEVIS trials (3/11 [27%] vs. 0/45 [0%], respectively, p=0.03). Statistical significance was not reached for peak grade IV VGE (2/11 [18%] vs. 3/45 [7%], p=0.149) or cumulative grade IV VGE observations per subject-trial (8/128 [6%] vs. 26/630 [4%], p=0.151). Microparticle data were collected for 5/11 trials (3 with DCS outcomes), with widely varying patterns that could not be resolved statistically

  13. Weak-Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-Line Regions?

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad; Trakhtenbrot, B.; Anderson, S. F.; Brandt, W. N.; Diamond-Stanic, A. M.; Fan, X.; Lira, P.; Netzer, H.; Plotkin, R. M.; Richards, G. T.; Schneider, D. P.; Strauss, M. A.

    2011-01-01

    We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z=3.55 and SDSS J123743.08+630144.9 at z=3.49. In both sources we detect an unusually weak broad Hβ line and we place tight upper limits on the strengths of their [O III] lines. Virial, Hβ-based black-hole mass determinations indicate normalized accretion rates of L/LEdd=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of Γ=1.91+0.24-0.22which supports the virial L/LEdd determination in this source. Our results suggest that the weakness of the broad-emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad-emission line region properties.

  14. Pathology: whales, sonar and decompression sickness.

    PubMed

    Piantadosi, Claude A; Thalmann, Edward D

    2004-04-15

    We do not yet know why whales occasionally strand after sonar has been deployed nearby, but such information is important for both naval undersea activities and the protection of marine mammals. Jepson et al. suggest that a peculiar gas-forming disease afflicting some stranded cetaceans could be a type of decompression sickness (DCS) resulting from exposure to mid-range sonar. However, neither decompression theory nor observation support the existence of a naturally occurring DCS in whales that is characterized by encapsulated, gas-filled cavities in the liver. Although gas-bubble formation may be aggravated by acoustic energy, more rigorous investigation is needed before sonar can be firmly linked to bubble formation in whales. PMID:15085881

  15. Gender not a factor for altitude decompression sickness risk

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Kannan, Nandini; Pilmanis, Andrew A.

    2003-01-01

    INTRODUCTION: Early, retrospective reports of the incidence of altitude decompression sickness (DCS) during altitude chamber training exposures indicated that women were more susceptible than men. We hypothesized that a controlled, prospective study would show no significant difference. METHODS: We conducted 25 altitude chamber decompression exposure profiles. A total of 291 human subjects, 197 men and 94 women, underwent 961 exposures to simulated altitude for up to 8 h, using zero to 4 h of preoxygenation. Throughout the exposures, subjects breathed 100% oxygen, rested or performed mild or strenuous exercise, and were monitored for precordial venous gas emboli (VGE) and DCS symptoms. RESULTS: No significant differences in DCS incidence were observed between men (49.5%) and women (45.3%). However, VGE occurred at significantly higher rates among men than women under the same exposure conditions, 69.3% and 55.0% respectively. Women using hormonal contraception showed significantly greater susceptibility to DCS than those not using hormonal contraception during the latter two weeks of the menstrual cycle. Significantly higher DCS incidence was observed in the heaviest men, in women with the highest body fat, and in subjects with the highest body mass indices and lowest levels of fitness. CONCLUSION: No differences in altitude DCS incidence were observed between the sexes under our test conditions, although men developed VGE more often than women. Age and height showed no significant influence on DCS incidence, but persons of either sex with higher body mass index and lower physical fitness developed DCS more frequently.

  16. Space Flight Decompression Sickness Contingency Plan

    NASA Technical Reports Server (NTRS)

    Dervay, Joseph; Gernhardt, Michael L.; Ross, Charles E.; Hamilton, Douglas; Homick, Jerry L. (Technical Monitor)

    2000-01-01

    The purpose was to develop an enhanced plan to diagnose, treat, and manage decompression sickness (DCS) during extravehicular activity (EVA). This plan is merited by the high frequency of upcoming EVAs necessary to construct and maintain the International Space Station (ISS). The upcoming ISS era will demand a significant increase in EVA. The DCS Risk and Contingency Plan provided a new and improved approach to DCS reporting, treatment, management, and training.

  17. Cerebrospinal Fluid Leakage after Thoracic Decompression

    PubMed Central

    Hu, Pan-Pan; Liu, Xiao-Guang; Yu, Miao

    2016-01-01

    Objective: The objective of this study is to review cerebrospinal fluid leakage (CSFL) after thoracic decompression and describe its regular and special features. Data Sources: Literature cited in this review was retrieved from PubMed and Medline and was primarily published during the last 10 years. “Cerebrospinal fluid”, “leakage”, “dural tears”, and “thoracic decompression” were the indexed terms. Relevant citations in the retrieved articles were also screened to include more data. Study Selection: All retrieved literature was scrutinized, and four categories were recorded: incidence and risk factors, complications, treatment modalities, and prognosis. Results: CSFL is much more frequent after thoracic decompression than after cervical and lumbar spinal surgeries. Its occurrence is related to many clinical factors, especially the presence of ossified ligaments and the adhesion of the dural sac. While its impact on the late neurological recovery is currently controversial, CSFL increases the risk of other perioperative complications, such as low intracranial pressure symptoms, infection, and vascular events. The combined use of primary repairs during the operation and conservative treatment postoperatively is generally effective for most CSFL cases, whereas lumbar drains and reoperations should be implemented as rescue options for refractory cases only. Conclusions: CSFL after thoracic decompression has not been specifically investigated, so the present study provides a systematic and comprehensive review of the issue. CSFL is a multi-factor-related complication, and pathological factors play a decisive role. The importance of CSFL is in its impact on the increased risk of other complications during the postoperative period. Methods to prevent these complications are in need. In addition, though the required treatment resources are not special for CSFL after thoracic decompression, most CSFL cases are conservatively curable, and surgeons should be

  18. Clinical outcomes following sublaminar decompression and instrumented fusion for lumbar degenerative spinal pathology.

    PubMed

    Peddada, Kranti; Elder, Benjamin D; Ishida, Wataru; Lo, Sheng-Fu L; Goodwin, C Rory; Boah, Akwasi O; Witham, Timothy F

    2016-08-01

    Traditional treatment for lumbar stenosis with instability is laminectomy and posterolateral arthrodesis, with or without interbody fusion. However, laminectomies remove the posterior elements and decrease the available surface area for fusion. Therefore, a sublaminar decompression may be a preferred approach for adequate decompression while preserving bone surface area for fusion. A retrospective review of 71 patients who underwent sublaminar decompression in conjunction with instrumented fusion for degenerative spinal disorders at a single institution was performed. Data collected included demographics, preoperative symptoms, operative data, and radiographical measurements of the central canal, lateral recesses, and neural foramina, and fusion outcomes. Paired t-tests were used to test significance of the outcomes. Thirty-one males and 40 females with a median age 60years underwent sublaminar decompression and fusion. A median of two levels were fused. The mean Visual Analog Scale pain score improved from 6.7 preoperatively to 2.9 at last follow-up. The fusion rate was 88%, and the median time to fusion was 11months. Preoperative and postoperative mean thecal sac cross-sectional area, right lateral recess height, left lateral recess height, right foraminal diameter, and left foraminal diameter were 153 and 209mm(2) (p<0.001), 5.9 and 5.9mm (p=0.43), 5.8 and 6.3mm (p=0.027), 4.6 and 5.2mm (p=0.008), and 4.2 and 5.2mm (p<0.001), respectively. Sublaminar decompression provided adequate decompression, with significant increases in thecal sac cross-sectional area and bilateral foraminal diameter. It may be an effective alternative to laminectomy in treating central and foraminal stenosis in conjunction with instrumented fusion. PMID:27056673

  19. Plants survive rapid decompression: Implications for bioregenerative life support

    NASA Astrophysics Data System (ADS)

    Wheeler, R. M.; Wehkamp, C. A.; Stasiak, M. A.; Dixon, M. A.; Rygalov, V. Y.

    2011-05-01

    Radish (Raphanus sativus), lettuce (Latuca sativa), and wheat (Triticum aestivum) plants were grown at either 98 kPa (ambient) or 33 kPa atmospheric pressure with constant 21 kPa oxygen and 0.12 kPa carbon dioxide in atmospherically closed pressure chambers. All plants were grown rockwool using recirculating hydroponics with a complete nutrient solution. At 20 days after planting, chamber pressures were pumped down as rapidly as possible, reaching 5 kPa after about 5 min and ˜1.5 kPa after about 10 min. The plants were held at 1.5 kPa for 30 min and then pressures were restored to their original settings. Temperature (22 °C) and humidity (65% RH) controls were engaged throughout the depressurization, although temperatures dropped to near 16 °C for a brief period. CO2 and O2 were not detectable at the low pressure, suggesting that most of the 1.5 kPa atmosphere consisted of water vapor. Following re-pressurization, plants were grown for another 7 days at the original pressures and then harvested. The lettuce, radish, and wheat plants showed no visible effects from the rapid decompression, and there were no differences in fresh or dry mass when compared to control plants maintained continuously at 33 or 98 kPa. But radish storage root fresh mass and lettuce head fresh and dry masses were less at 33 kPa compared to 98 kPa for both the controls and decompression treatment. The results suggest that plants are extremely resilient to rapid decompression, provided they do not freeze (from evaporative cooling) or desiccate. The water of the hydroponic system was below the boiling pressure during these tests and this may have protected the plants by preventing pressures from dropping below 1.5 kPa and maintaining humidity near 1.5 kPa. Further testing is needed to determine how long plants can withstand such low pressure, but the results suggest there are at least 30 min to respond to catastrophic pressure losses in a plant production chamber that might be used for life

  20. Magma chamber paradox: decompression upon replenishment

    NASA Astrophysics Data System (ADS)

    Papale, Paolo; Longo, Antonella; Montagna, Chiara Paola

    2013-04-01

    The invasion of active magma chambers by fresh magma of deeper provenance is invariably assumed to cause chamber pressurization. Pressure increase thus stands as an intuitive consequence of magma chamber replenishment. However, new numerical simulations demonstrate that pressure evolution is highly non-linear, and that decompression dominates when large density contrasts exist between injected and resident magmas. This apparent paradox originates from the compressible nature of volatile-rich magma and the dynamics of convection associated with injections of buoyant magma. While decompression can dominate in a shallow chamber, pressure increase develops in the connected deep regions of magma provenance. These results contradict classical views adopted to interpret observations at active as well as fossil magma chambers, and demonstrate that a simple reliance on intuition is insufficient: what may be perceived as a paradox - magma chamber decompression upon replenishment - is instead likely, and rooted in the complex physics that governs the multiphase, multi-component dynamics of magma transport in geometrically composite, spatially extended magmatic systems.

  1. Recreational technical diving part 2: decompression from deep technical dives.

    PubMed

    Doolette, David J; Mitchell, Simon J

    2013-06-01

    Technical divers perform deep, mixed-gas 'bounce' dives, which are inherently inefficient because even a short duration at the target depth results in lengthy decompression. Technical divers use decompression schedules generated from modified versions of decompression algorithms originally developed for other types of diving. Many modifications ostensibly produce shorter and/or safer decompression, but have generally been driven by anecdote. Scientific evidence relevant to many of these modifications exists, but is often difficult to locate. This review assembles and examines scientific evidence relevant to technical diving decompression practice. There is a widespread belief that bubble algorithms, which redistribute decompression in favour of deeper decompression stops, are more efficient than traditional, shallow-stop, gas-content algorithms, but recent laboratory data support the opposite view. It seems unlikely that switches from helium- to nitrogen-based breathing gases during ascent will accelerate decompression from typical technical bounce dives. However, there is evidence for a higher prevalence of neurological decompression sickness (DCS) after dives conducted breathing only helium-oxygen than those with nitrogen-oxygen. There is also weak evidence suggesting less neurological DCS occurs if helium-oxygen breathing gas is switched to air during decompression than if no switch is made. On the other hand, helium-to-nitrogen breathing gas switches are implicated in the development of inner-ear DCS arising during decompression. Inner-ear DCS is difficult to predict, but strategies to minimize the risk include adequate initial decompression, delaying helium-to-nitrogen switches until relatively shallow, and the use of the maximum safe fraction of inspired oxygen during decompression. PMID:23813463

  2. Global and Local Distortion Inference During Embedded Zerotree Wavelet Decompression

    NASA Technical Reports Server (NTRS)

    Huber, A. Kris; Budge, Scott E.

    1996-01-01

    This paper presents algorithms for inferring global and spatially local estimates of the squared-error distortion measures for the Embedded Zerotree Wavelet (EZW) image compression algorithm. All distortion estimates are obtained at the decoder without significantly compromising EZW's rate-distortion performance. Two methods are given for propagating distortion estimates from the wavelet domain to the spatial domain, thus giving individual estimates of distortion for each pixel of the decompressed image. These local distortion estimates seem to provide only slight improvement in the statistical characterization of EZW compression error relative to the global measure, unless actual squared errors are propagated. However, they provide qualitative information about the asymptotic nature of the error that may be helpful in wavelet filter selection for low bit rate applications.

  3. Differential Effects of Temperature Extremes on Hospital Admission Rates for Respiratory Disease between Indigenous and Non-Indigenous Australians in the Northern Territory.

    PubMed

    Green, Donna; Bambrick, Hilary; Tait, Peter; Goldie, James; Schultz, Rosalie; Webb, Leanne; Alexander, Lisa; Pitman, Andrew

    2015-12-01

    The health gap between Indigenous and non-Indigenous Australians may be exacerbated by climate change if temperature extremes have disproportionate adverse effects on Indigenous people. To explore this issue, we analysed the effect of temperature extremes on hospital admissions for respiratory diseases, stratified by age, Indigenous status and sex, for people living in two different climates zones in the Northern Territory during the period 1993-2011. We examined admissions for both acute and chronic respiratory diagnoses, controlling for day of the week and seasonality variables. Our analysis showed that: (1) overall, Indigenous hospital admission rates far exceeded non-Indigenous admission rates for acute and chronic diagnoses, and Top End climate zone admission rates exceeded Central Australia climate zone admission rates; (2) extreme cold and hot temperatures were associated with inconsistent changes in admission rates for acute respiratory disease in Indigenous and non-Indigenous children and older adults; and (3) no response to cold or hot temperature extremes was found for chronic respiratory diagnoses. These findings support our two hypotheses, that extreme hot and cold temperatures have a different effect on hospitalisations for respiratory disease between Indigenous and non-Indigenous people, and that these health risks vary between the different climate zones. We did not, however, find that there were differing responses to temperature extremes in the two populations, suggesting that any increased vulnerability to climate change in the Indigenous population of the Northern Territory arises from an increased underlying risk to respiratory disease and an already greater existing health burden. PMID:26633456

  4. Differential Effects of Temperature Extremes on Hospital Admission Rates for Respiratory Disease between Indigenous and Non-Indigenous Australians in the Northern Territory

    PubMed Central

    Green, Donna; Bambrick, Hilary; Tait, Peter; Goldie, James; Schultz, Rosalie; Webb, Leanne; Alexander, Lisa; Pitman, Andrew

    2015-01-01

    The health gap between Indigenous and non-Indigenous Australians may be exacerbated by climate change if temperature extremes have disproportionate adverse effects on Indigenous people. To explore this issue, we analysed the effect of temperature extremes on hospital admissions for respiratory diseases, stratified by age, Indigenous status and sex, for people living in two different climates zones in the Northern Territory during the period 1993–2011. We examined admissions for both acute and chronic respiratory diagnoses, controlling for day of the week and seasonality variables. Our analysis showed that: (1) overall, Indigenous hospital admission rates far exceeded non-Indigenous admission rates for acute and chronic diagnoses, and Top End climate zone admission rates exceeded Central Australia climate zone admission rates; (2) extreme cold and hot temperatures were associated with inconsistent changes in admission rates for acute respiratory disease in Indigenous and non-Indigenous children and older adults; and (3) no response to cold or hot temperature extremes was found for chronic respiratory diagnoses. These findings support our two hypotheses, that extreme hot and cold temperatures have a different effect on hospitalisations for respiratory disease between Indigenous and non-Indigenous people, and that these health risks vary between the different climate zones. We did not, however, find that there were differing responses to temperature extremes in the two populations, suggesting that any increased vulnerability to climate change in the Indigenous population of the Northern Territory arises from an increased underlying risk to respiratory disease and an already greater existing health burden. PMID:26633456

  5. Effect of plasma density on diffusion rates due to wave particle interactions with chorus and plasmaspheric hiss: extreme event analysis

    NASA Astrophysics Data System (ADS)

    Sicard-Piet, A.; Boscher, D.; Horne, R. B.; Meredith, N. P.; Maget, V.

    2014-08-01

    Wave particle interactions play an important role in controlling the dynamics of the radiation belts. The purpose of this study is to estimate how variations in the plasma density can affect diffusion rates resulting from interactions between chorus waves and plasmaspheric hiss with energetic particles and the resulting evolution of the energetic electron population. We perform a statistical analysis of the electron density derived from the plasma wave experiment on the CRRES satellite for two magnetic local time sectors corresponding to near midnight and near noon. We present the cumulative probability distribution of the electron plasma density for three levels of magnetic activity as measured by Kp. The largest densities are seen near L* = 2.5 while the smallest occur near L* = 6. The broadest distribution, corresponding to the greatest variability, occurs near L* = 4. We calculate diffusion coefficients for plasmaspheric hiss and whistler mode chorus for extreme values of the electron density and estimate the effects on the radiation belts using the Salammbô model. At L* = 4 and L* = 6, in the low density case, using the density from the 5th percentile of the cumulative distribution function, electron energy diffusion by chorus waves is strongest at 2 MeV and increases the flux by up to 3 orders of magnitude over a period of 24 h. In contrast, in the high density case, using the density from the 95th percentile, there is little acceleration at energies above 800 keV at L* = 6, and virtually no acceleration at L* = 4. In this case the strongest energy diffusion occurs at lower energies around 400 keV where the flux at L* = 6 increases 3 orders of magnitude.

  6. Paradoxical Herniation After Unilateral Decompressive Craniectomy Predicts Better Patient Survival: A Retrospective Analysis of 429 Cases.

    PubMed

    Chen, Weiqiang; Guo, Jingfang; Wu, Jin; Peng, Guoyi; Huang, Mindong; Cai, Chuwei; Yang, Yingming; Wang, Shousen

    2016-03-01

    Paradoxical herniation (PH) is a life-threatening emergency after decompressive craniectomy. In the current study, we examined patient survival in patients who developed PH after decompressive craniectomy versus those who did not. Risk factors for, and management of, PH were also analyzed. This retrospective analysis included 429 consecutive patients receiving decompressive craniectomy during a period from January 2007 to December 2012. Mortality rate and Glasgow Outcome Scale (GOS) were compared between those who developed PH (n = 13) versus those who did not (n = 416). A stepwise multivariate logistic regression analysis was carried out to examine the risk factors for PH. The overall mortality in the entire sample was 22.8%, with a median follow-up of 6 months. Oddly enough, all 13 patients who developed PH survived beyond 6 months. Glasgow Coma Scale did not differ between the 2 groups upon admission, but GOS was significantly higher in subjects who developed PH. Both the disease type and coma degree were comparable between the 13 PH patients and the remaining 416 patients. In all PH episodes, patients responded to emergency treatments that included intravenous hydration, cerebral spinal fluid drainage discontinuation, and Trendelenburg position. A regression analysis indicated the following independent risk factors for PH: external ventriculostomy, lumbar puncture, and continuous external lumbar drainage. The rate of PH is approximately 3% after decompressive craniectomy. The most intriguing findings of the current study were the 0% mortality in those who developed PH versus 23.6% mortality in those who did not develop PH and significant difference of GOS score at 6-month follow-up between the 2 groups, suggesting that PH after decompressive craniectomy should be managed aggressively. The risk factors for PH include external ventriculostomy, ventriculoperitoneal shunt, lumbar puncture, and continuous external lumbar drainage. PMID:26945365

  7. Analytic gain in probabilistic decompression sickness models.

    PubMed

    Howle, Laurens E

    2013-11-01

    Decompression sickness (DCS) is a disease known to be related to inert gas bubble formation originating from gases dissolved in body tissues. Probabilistic DCS models, which employ survival and hazard functions, are optimized by fitting model parameters to experimental dive data. In the work reported here, I develop methods to find the survival function gain parameter analytically, thus removing it from the fitting process. I show that the number of iterations required for model optimization is significantly reduced. The analytic gain method substantially improves the condition number of the Hessian matrix which reduces the model confidence intervals by more than an order of magnitude. PMID:24209920

  8. Radiological considerations: percutaneous laser disc decompression.

    PubMed

    Botsford, J A

    1993-10-01

    Diagnostic radiology is an integral part of percutaneous laser disc decompression (PLDD). All physicians involved in PLDD patient selection and treatment must be familiar with the imaging techniques unique to this procedure to ensure a successful outcome. The following review is based on the cumulative experience gained in performing over 150 PLDD procedures. It discusses the function of diagnostic radiology in all facets of PLDD including patient selection, intraoperative imaging, postoperative evaluation, and analysis of complications. Fundamental radiologic concepts that apply to PLDD are explained and protocols suggested to optimize results and avoid complications. PMID:10146513

  9. Colonic Fermentation Promotes Decompression sickness in Rats.

    PubMed

    de Maistre, Sébastien; Vallée, Nicolas; Gempp, Emmanuel; Lambrechts, Kate; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body's H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production. PMID:26853722

  10. Microsurgical Decompression for Peroneal Nerve Entrapment Neuropathy

    PubMed Central

    MORIMOTO, Daijiro; ISU, Toyohiko; KIM, Kyongsong; SUGAWARA, Atsushi; YAMAZAKI, Kazuyoshi; CHIBA, Yasuhiro; IWAMOTO, Naotaka; ISOBE, Masanori; MORITA, Akio

    2015-01-01

    Peroneal nerve entrapment neuropathy (PNEN) is one cause of numbness and pain in the lateral lower thigh and instep, and of motor weakness of the extensors of the toes and ankle. We report a less invasive surgical procedure performed under local anesthesia to treat PNEN and our preliminary outcomes. We treated 22 patients (33 legs), 7 men and 15 women, whose average age was 66 years. The mean postoperative follow-up period was 40 months. All patients complained of pain or paresthesia of the lateral aspect of affected lower thigh and instep; all manifested a Tinel-like sign at the entrapment point. As all had undergone unsuccessful conservative treatment, we performed microsurgical decompression under local anesthesia. Of 19 patients who had undergone lumbar spinal surgery (LSS), 9 suffered residual symptoms attributable to PNEN. While complete symptom abatement was obtained in the other 10 they later developed PNEN-induced new symptoms. Motor weakness of the extensors of the toes and ankle [manual muscle testing (MMT) 4/5] was observed preoperatively in 8 patients; it was relieved by microsurgical decompression. Based on self-assessments, all 22 patients were satisfied with the results of surgery. PNEN should be considered as a possible differential diagnosis in patients with L5 neuropathy due to lumbar degenerative disease, and as a causative factor of residual symptoms after LSS. PNEN can be successfully addressed by less-invasive surgery performed under local anesthesia. PMID:26227056

  11. Microsurgical Decompression for Peroneal Nerve Entrapment Neuropathy.

    PubMed

    Morimoto, Daijiro; Isu, Toyohiko; Kim, Kyongsong; Sugawara, Atsushi; Yamazaki, Kazuyoshi; Chiba, Yasuhiro; Iwamoto, Naotaka; Isobe, Masanori; Morita, Akio

    2015-01-01

    Peroneal nerve entrapment neuropathy (PNEN) is one cause of numbness and pain in the lateral lower thigh and instep, and of motor weakness of the extensors of the toes and ankle. We report a less invasive surgical procedure performed under local anesthesia to treat PNEN and our preliminary outcomes. We treated 22 patients (33 legs), 7 men and 15 women, whose average age was 66 years. The mean postoperative follow-up period was 40 months. All patients complained of pain or paresthesia of the lateral aspect of affected lower thigh and instep; all manifested a Tinel-like sign at the entrapment point. As all had undergone unsuccessful conservative treatment, we performed microsurgical decompression under local anesthesia. Of 19 patients who had undergone lumbar spinal surgery (LSS), 9 suffered residual symptoms attributable to PNEN. While complete symptom abatement was obtained in the other 10 they later developed PNEN-induced new symptoms. Motor weakness of the extensors of the toes and ankle [manual muscle testing (MMT) 4/5] was observed preoperatively in 8 patients; it was relieved by microsurgical decompression. Based on self-assessments, all 22 patients were satisfied with the results of surgery. PNEN should be considered as a possible differential diagnosis in patients with L5 neuropathy due to lumbar degenerative disease, and as a causative factor of residual symptoms after LSS. PNEN can be successfully addressed by less-invasive surgery performed under local anesthesia. PMID:26227056

  12. Submarine tower escape decompression sickness risk estimation.

    PubMed

    Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

    2014-01-01

    Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models. PMID:25109085

  13. Hyperbaric oxygen treatment for decompression sickness.

    PubMed

    Moon, R E

    2014-01-01

    Decompression sickness (DCS) is a clinical syndrome occurring usually within 24 hours of a reduction in ambient pressure. DCS occurs most commonly in divers ascending from a minimum depth of 20 feet (6 meters) of sea water, but can also occur during rapid decompression from sea level to altitude (typically > 17,000 feet / 5,200 meters). Manifestations are one or more of the following: most commonly, joint pain, hypesthesia, generalized fatigue or rash; less common but more serious, motor weakness, ataxia, pulmonary edema, shock and death. The cause of DCS is in situ bubble formation in tissues, causing mechanical disruption of tissue, occlusion of blood flow, platelet activation, endothelial dysfunction and capillary leakage. High inspired concentration of oxygen (O2) is recommended as first aid for all cases and can be definitive treatment for most altitude DCS. For most other cases, hyperbaric oxygen is recommended,most commonly 100% O2 breathing at 2.82 atmospheres absolute (U.S.Navy Treatment Table 6 or equivalent). Additional treatments (generally no more than one to two) are used for residual manifestations until clinical stability; some severe cases may require more treatments. Isotonic, glucose-free fluids are recommended for prevention and treatment of hypovolemia. An evidence-based review of adjunctive therapies is presented. PMID:24851553

  14. Colonic Fermentation Promotes Decompression sickness in Rats

    PubMed Central

    de Maistre, Sébastien; Vallée, Nicolas; Gempp, Emmanuel; Lambrechts, Kate; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body’s H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production. PMID:26853722

  15. A New Measure of Decompression Sickness in the Rat

    PubMed Central

    Wang, Qiong; Lambrechts, Kate; Mansourati, Jacques

    2014-01-01

    In this study we assessed the reliability of a tilting-board grip score as a measure of decompression sickness in rats. In experiments using a hyperbaric compression/decompression protocol, rats were observed for signs of decompression sickness and their grip strength measured on a tilting particle board hinged to a metal frame. Angles at which rats lost grip were converted to gravitational vectors. Decreased mean grip scores following decompression were fitted to a logistic regression model with strain, age, and weight. Decrease in grip score was significantly associated with observed decompression sickness (P = 0.0036). The log odds ratio for decompression sickness = 1.40 (decrease in grip score). In rats with no decrease in mean grip score there was a 50% probability of decompression sickness (pDCS). This increased steadily with decreases in mean grip score. A decrease of 0.3 had a 60% pDCS, a decrease of 0.6 had a 70% pDCS, and a decrease of 2.1 had a 95% pDCS. The tilting board grip score is a reliable measure of the probability of decompression sickness. PMID:24963469

  16. Clopidogrel reduces the inflammatory response of lung in a rat model of decompression sickness.

    PubMed

    Bao, Xiao-Chen; Chen, Hong; Fang, Yi-Qun; Yuan, Heng-Rong; You, Pu; Ma, Jun; Wang, Fang-Fang

    2015-06-01

    Inflammation and platelet activation are critical phenomena in the setting of decompression sickness. Clopidogrel (Clo) inhibits platelet activation and may also reduce inflammation. The goal of this study was to investigate if Clo had a protective role in decompression sickness (DCS) through anti-inflammation way. Male Sprague-Dawley rats (n=111) were assigned to three groups: control+vehicle group, DCS+vehicle, DCS+Clo group. The experimental group received 50 mg/kg of Clo or vehicle for 3 days, then compressed to 1,600 kPa (150 msw) in 28 s, maintained at 150 msw for 242 s and decompressed to surface at 3m/s. In a control experiment, rats were also treated with vehicle for 3 days and maintained at atmospheric pressure for an equivalent period of time. Clinical assessment took place over a period of 30 min after surfacing. At the end, blood samples were collected for blood cells counts and cytokine detection. The pathology and the wet/dry ratio of lung tissues, immunohistochemical detection of lung tissue CD41 expression, the numbers of P-selectin positive platelets and platelet-leukocyte conjugates in blood were tested. We found that Clo significantly reduced the DCS mortality risk (mortality rate: 11/45 with Clo vs. 28/46 in the untreated group, P<0.01). Clo reduced the lung injury, the wet/dry ratio of lung, the accumulation of platelet and leukocyte in lung, the fall in platelet count, the WBC count, the numbers of activated platelets and platelet-leukocyte complexes in peripheral blood. It was concluded that Clo can play a protective role in decompression sickness through reducing post-decompression platelet activation and inflammatory process. PMID:25784626

  17. Management of Pelvic Chondroblastic Osteosarcoma after Urgent Spinal Decompression - A Report of 2 Cases

    PubMed Central

    Scudday, Travis Spencer; Danisa, Olumide Ayodele; Zuckerman, Lee Michael

    2016-01-01

    Introduction: Pelvic sarcoma presenting with neurologic symptoms is rare. Workup of neurological deficits, whether elective or emergent should address the possibility of a space occupying lesion including pelvic sarcoma. Poor biopsy technique and incomplete workup of musculoskeletal tumors results in misdiagnosis or major errors in 18% of biopsies. The sequelae of a suboptimal biopsy include local recurrence, a more extensive resection, or extremity amputation. Pelvic chondroblastic osteosarcoma presenting with neurological deficits has not been previously reported. We report two cases of chondroblastic osteosarcoma that were treated with urgent decompression of the lumbar spine due to neurologic symptoms. Case presentations: Our two cases, a 25 year old Hispanic female and 22 year old Hispanic male, both presented with neurologic changes due to a space occupying tumor in the lumbar spine and pelvis. Both underwent spinal decompression following incomplete workup. A repeat biopsy was required in both cases due to a questionable initial diagnosis. Once the diagnosis was confirmed, they underwent definitive resection and treatment that was more morbid due to the primary decompressions. Conclusion: We stress the importance of proper biopsy techniques as well as the need to complete a full preoperative staging workup prior to any surgical procedures involving musculoskeletal tumors. We review the current literature on lumbar chondroblastic osteosarcomas and review the issues surrounding biopsy of musculoskeletal tumors. Our cases underline the need for complete workup and correct biopsy techniques to ensure patients have the best chance at tumor free survival with minimal morbidity. PMID:27299134

  18. Surgical techniques of anterior decompression and fusion for spinal cord injuries.

    PubMed

    Bohlman, H H; Eismont, F J

    1981-01-01

    Many patients who have static or only slowly improving neurologic deficits and significant compression of the spinal cord and nerve roots can benefit from anterior decompression. The improvement ranges from partial root recovery to very dramatic improvement in upper as well as lower extremities in the patient with quadriparesis. Intrinsic damage or contusion of the spinal cord cannot be reversed by decompression. Patients with motor sparing preoperatively attain a better functional improvement than those patients who have only slight distal sensory function initially. The same can be said of patients with spinal cord injuries treated with surgery, but we believe the ultimate degree of functional recovery of incomplete cord injuries is greater following anterior than posterior decompression when the operation is indicated. An early accurate diagnosis must be made concerning whether a patient has a complete or an incomplete spinal cord injury. The mechanical compressive lesion must be well documented by myelography, laminography, or CAT scan. The patient should not be neurologically harmed by a posterior laminectomy approach to anterior pathology which additionally removes all posterior stability. An anterior compressive block is best removed through an anterior approach. PMID:7471590

  19. Ambulation Increases Decompression Sickness in Spacewalk Simulations

    NASA Technical Reports Server (NTRS)

    Pollock, N. W.; Natoli, M. J.; Conkin, J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    Musculoskeletal activity has the potential to both improve and compromise decompression safety. Exercise enhances inert gas elimination during oxygen breathing prior to decompression (prebreathe), but it may also promote bubble nuclei formation (nucleation), which can lead to gas phase separation and bubble growth and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity and the level of tissue supersaturation may be critical to the net effect. Understanding the relationships is important to evaluate exercise prebreathe protocols and quantify decompression risk in gravity and microgravity environments. Data gathered during NASA's Prebreathe Reduction Program (PRP) studies combined oxygen prebreathe and exercise followed by low pressure (4.3 psi; altitude equivalent of 30,300 ft [9,235 m]) microgravity simulation to produce two protocols used by astronauts preparing for extravehicular activity. Both the Phase II/CEVIS (cycle ergometer vibration isolation system) and ISLE (in-suit light exercise) trials eliminated ambulation to more closely simulate the microgravity environment. The CEVIS results (35 male, 10 female) serve as control data for this NASA/Duke study to investigate the influence of ambulation exercise on bubble formation and the subsequent risk of DCS. METHODS Four experiments will replicate the CEVIS exercise-enhanced oxygen prebreathe protocol, each with a different exception. The first of these is currently underway. Experiment 1 - Subjects complete controlled ambulation (walking in place with fixed cadence and step height) during both preflight and at 4.3 psi instead of remaining nonambulatory throughout. Experiment 2 - Subjects remain non-ambulatory during the preflight period and ambulatory at 4.3 psi. Experiment 3 - Subjects ambulate during the preflight period and remain non-ambulatory at 4.3 psi. Experiment 4 - The order of heavy and light exercise employed in the CEVIS protocol is

  20. Developments in time-resolved high pressure x-ray diffraction using rapid compression and decompression

    SciTech Connect

    Smith, Jesse S.; Sinogeikin, Stanislav V.; Lin, Chuanlong; Rod, Eric; Bai, Ligang; Shen, Guoyin

    2015-07-15

    Complementary advances in high pressure research apparatus and techniques make it possible to carry out time-resolved high pressure research using what would customarily be considered static high pressure apparatus. This work specifically explores time-resolved high pressure x-ray diffraction with rapid compression and/or decompression of a sample in a diamond anvil cell. Key aspects of the synchrotron beamline and ancillary equipment are presented, including source considerations, rapid (de)compression apparatus, high frequency imaging detectors, and software suitable for processing large volumes of data. A number of examples are presented, including fast equation of state measurements, compression rate dependent synthesis of metastable states in silicon and germanium, and ultrahigh compression rates using a piezoelectric driven diamond anvil cell.

  1. A novel sling technique for microvascular decompression of a rare anomalous vertebral artery causing cervical radiculopathy.

    PubMed

    Tandon, Adesh; Chandela, Sid; Langer, David; Sen, Chandranath

    2013-09-01

    Cervical radiculopathy secondary to compression from congenital anomalous vertebral arteries (VAs) is a known entity. Patients present with a variety of symptoms ranging from upper-extremity numbness to true occipital neuralgia. Treatment options for extracranial tortuous VAs include conservative management or some form of surgical microvascular decompression (MVD). The authors report on a patient with a congenital anomalous VA loop causing cervical nerve root compression. Successful MVD was conducted with relief of the patient's symptoms. A novel sling technique was used for mobilization of the VA. To the authors' knowledge, this is the first MVD described utilizing this technique. PMID:23991815

  2. Percutaneous laser disc decompression: a 17-year experience.

    PubMed

    Choy, Daniel S J

    2004-10-01

    In this review, we analyze our effort to demonstrate the effectiveness of a new approach to the treatment of herniated disc disease using Nd:YAG laser energy introduced into a herniated disc under fluoroscopic control and local anesthesia. 2400 PLDD procedures (combined number of decompressions in cervical, thoracic, and lumbar discs were performed in the past 18(1/2) years in 1275 patients. The overall success rate according to the MacNab criteria was 89%. The complication rate (only infectious disciitis) was 0.4%; all 10 patients with complications were cured with appropriate antibiotics. The recurrence rate was 5%, and usually due to reinjury. There were no deaths, and no cases of nerve or cord damage. PLDD is a safe and effective outpatient procedure for the treatment of herniated disc disease with the advantages of relative non-invasiveness, usually immediate relief of back and sciatic pain, early return to work (generally 5-6 days), and a low complication and recurrence rate. It can also be repeated if necessary as many as five times. PMID:15671713

  3. Analysis and trends of precipitation lapse rate and extreme indices over north Sikkim eastern Himalayas under CMIP5ESM-2M RCPs experiments

    NASA Astrophysics Data System (ADS)

    Singh, Vishal; Goyal, Manish Kumar

    2016-01-01

    This paper draws attention to highlight the spatial and temporal variability in precipitation lapse rate (PLR) and precipitation extreme indices (PEIs) through the mesoscale characterization of Teesta river catchment, which corresponds to north Sikkim eastern Himalayas. A PLR rate is an important variable for the snowmelt runoff models. In a mountainous region, the PLR could be varied from lower elevation parts to high elevation parts. In this study, a PLR was computed by accounting elevation differences, which varies from around 1500 m to 7000 m. A precipitation variability and extremity were analysed using multiple mathematical functions viz. quantile regression, spatial mean, spatial standard deviation, Mann-Kendall test and Sen's estimation. For this reason, a daily precipitation, in the historical (years 1980-2005) as measured/observed gridded points and projected experiments for the 21st century (years 2006-2100) simulated by CMIP5 ESM-2 M model (Coupled Model Intercomparison Project Phase 5 Earth System Model 2) employing three different radiative forcing scenarios (Representative Concentration Pathways), utilized for the research work. The outcomes of this study suggest that a PLR is significantly varied from lower elevation to high elevation parts. The PEI based analysis showed that the extreme high intensity events have been increased significantly, especially after 2040s. The PEI based observations also showed that the numbers of wet days are increased for all the RCPs. The quantile regression plots showed significant increments in the upper and lower quantiles of the various extreme indices. The Mann-Kendall test and Sen's estimation tests clearly indicated significant changing patterns in the frequency and intensity of the precipitation indices across all the sub-basins and RCP scenario in an intra-decadal time series domain. The RCP8.5 showed extremity of the projected outcomes.

  4. Early Decompression of Acute Subdural Hematoma for Postoperative Neurological Improvement: A Single Center Retrospective Review of 10 Years

    PubMed Central

    Oh, Chang Hyun; Shim, Yu Shik; Hyun, Dongkeun; Park, Hyeonseon; Kim, Eunyoung

    2016-01-01

    Objective This study was conducted to investigate survival related factors, as well as to evaluate the effects of early decompression on acute subdural hematoma (ASDH). Methods We retrospectively reviewed cases of decompressive craniectomy (DC) for decade. In total, 198 cases of DC involved ASDH were available for review, and 65 cases were excluded due to missing data on onset time and a delayed operation after closed observation with medical care. Finally, 133 cases of DC with ASDH were included in this study, and various factors including the time interval between trauma onset and operation were evaluated. Results In the present study, survival rate after DC in patients with ASDH was shown to be related to patient age (50 years old, p=0.012), brain compression ratio (p=0.042) and brain stem compression (p=0.020). Sex, preoperative mental status, and time interval between trauma onset and operation were not related with survival rate. Among those that survived (n=78), improvements in Glasgow Coma Scale (GCS) score of more than three points, compared to preoperative measurement, were more frequently observed among the early (less than 3 hours between trauma onset and operation) decompressed cases (p=0.013). However, improvements of more than 4 or 5 points on the GCS were not affected by early decompression. Conclusion Early decompression of ASDH was not correlated with survival rate, but was related with neurological improvement (more than three points on the GCS). Accordingly, early decompression in ASDH, if indicated, may be of particular benefit. PMID:27182496

  5. Arterial gas emboli in altitude-induced decompression sickness

    NASA Technical Reports Server (NTRS)

    Pilmanis, Andrew A.; Olson, Robert M.

    1993-01-01

    Exposure to high altitudes can result in the evolved-gas condition referred to as decompression sickness (DCS). Ultrasonic monitoring techniques have clearly demonstrated the presence of venous gas emboli (VGE) during decompression. Although important to DCS research and our understanding of the physiological mechanisms of this condition, Venus gas emboli have not been considered clinically hazardous, unless in extreme numbers. Arterial gas emboli (AGE), on the other hand, are generally viewed with great concern. Arterial gas emboli can enter the cerebral arterial circulation and arrest blood flow resulting in potentially serious injury. Left ventricular gas emboli were observed with echo imaging in five volunteer subjects during exposure to simulated altitude. These serendipitous findings occurred during altitude exposure under 3 separate research protocols involving 79 subject exposures. The voluntary, fully informed consent of the subjects used in this research was obtained as required by AFR 169-3. A Hewlett-Packard SONOS 1000 Echo Imaging System was used to monitor for precordial gas emboli. The improved resolution of the SONOS 1000 appears to account for these new findings. Four subjects had high incidence DCS and VGE during previous research flights. One subject only had one flight. The altitudes and AGE onset times for the five cases were: (1) 25,500 ft/2:23, (2) 29,000 ft/0:27, (3) 19,500 ft/3:49, (4) 29,500 ft/3:15, and (5) 29,500 ft/1:31. In all five cases, at the time of AGE onset, the VGE scores were high from all monitored locations. Four of the cases were symptomatic at the time of AGE onset (pain and skin mottling). No cerebral manifestations were observed. All subjects were immediately recompressed to ground level and successfully treated with 2 hours of post-breathing or with hyperbaric oxygen therapy. In conclusion, previously undetected AGE were demonstrated--with and without DCS symptoms--during exposure to altitude. It appears that this gas

  6. Threshold altitude resulting in decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.; Calkins, Dick S.

    1990-01-01

    A review of case reports, hypobaric chamber training data, and experimental evidence indicated that the threshold for incidence of altitude decompression sickness (DCS) was influenced by various factors such as prior denitrogenation, exercise or rest, and period of exposure, in addition to individual susceptibility. Fitting these data with appropriate statistical models makes it possible to examine the influence of various factors on the threshold for DCS. This approach was illustrated by logistic regression analysis on the incidence of DCS below 9144 m. Estimations using these regressions showed that, under a noprebreathe, 6-h exposure, simulated EVA profile, the threshold for symptoms occurred at approximately 3353 m; while under a noprebreathe, 2-h exposure profile with knee-bends exercise, the threshold occurred at 7925 m.

  7. Transcranial Doppler ultrasound and the etiology of neurologic decompression sickness during altitude decompression

    NASA Technical Reports Server (NTRS)

    Norfleet, W. T.; Powell, M. R.; Kumar, K. Vasantha; Waligora, J.

    1993-01-01

    The presence of gas bubbles in the arterial circulation can occur from iatrogenic mishaps, cardiopulmonary bypass devices, or following decompression, e.g., in deep-sea or SCUBA diving or in astronauts during extravehicular activities (EVA). We have examined the pathophysiology of neurological decompression sickness in human subjects who developed a large number of small gas bubbles in the right side of the heart as a result of hypobaric exposures. In one case, gas bubbles were detected in the middle cerebral artery (MCA) and the subject developed neurological symptoms; a 'resting' patent foramen ovalae (PFO) was found upon saline contrast echocardiography. A PFO was also detected in another individual who developed Spencer Grade 4 precordial Doppler ultrasound bubbles, but no evidence was seen of arterialization of bubbles upon insonation of either the MCA or common carotid artery. The reason for this difference in the behavior of intracardiac bubbles in these two individuals is not known. To date, we have not found evidence of right-to-left shunting of bubbles through pulmonary vasculature. The volume of gas bubbles present following decompression is examined and compared with the number arising from saline contrast injection. The estimates are comparable.

  8. How extreme are extremes?

    NASA Astrophysics Data System (ADS)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2016-04-01

    High temperatures have an impact on the energy balance of any living organism and on the operational capabilities of critical infrastructures. Heat-wave indicators have been mainly developed with the aim of capturing the potential impacts on specific sectors (agriculture, health, wildfires, transport, power generation and distribution). However, the ability to capture the occurrence of extreme temperature events is an essential property of a multi-hazard extreme climate indicator. Aim of this study is to develop a standardized heat-wave indicator, that can be combined with other indices in order to describe multiple hazards in a single indicator. The proposed approach can be used in order to have a quantified indicator of the strenght of a certain extreme. As a matter of fact, extremes are usually distributed in exponential or exponential-exponential functions and it is difficult to quickly asses how strong was an extreme events considering only its magnitude. The proposed approach simplify the quantitative and qualitative communication of extreme magnitude

  9. Posterior decompression with instrumented fusion for thoracic myelopathy caused by ossification of the posterior longitudinal ligament.

    PubMed

    Yamazaki, Masashi; Okawa, Akihiko; Fujiyoshi, Takayuki; Furuya, Takeo; Koda, Masao

    2010-05-01

    We evaluated the clinical results of posterior decompression with instrumented fusion (PDF) for thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL). A total of 24 patients underwent PDF, and their surgical outcomes were evaluated by the Japanese Orthopaedic Association (JOA) scores (0-11 points) and by recovery rates calculated at 3, 6, 9 and 12 months after surgery and at a mean final follow-up of 4 years and 5 months. The mean JOA score before surgery was 3.7 points. Although transient paralysis occurred immediately after surgery in one patient (3.8%), all patients showed neurological recovery at the final follow-up with a mean JOA score of 8.0 points and a mean recovery rate of 58.1%. The mean recovery rate at 3, 6, 9 and 12 months after surgery was 36.7, 48.8, 54.0 and 56.8%, respectively. The median time point that the JOA score reached its peak value was 9 months after surgery. No patient chose additional anterior decompression surgery via thoracotomy. The present findings demonstrate that despite persistent anterior impingement of the spinal cord by residual OPLL, PDF can result in considerable neurological recovery with a low risk of postoperative paralysis. Since neurological recovery progresses slowly after PDF, we suggest that additional anterior decompression surgery is not desirable during the early stage of recovery. PMID:20049486

  10. Elective decompression of the left ventricle in pediatric patients may reduce the duration of venoarterial extracorporeal membrane oxygenation.

    PubMed

    Hacking, Douglas F; Best, Derek; d'Udekem, Yves; Brizard, Christian P; Konstantinov, Igor E; Millar, Johnny; Butt, Warwick

    2015-04-01

    We aimed to determine the effect of elective left heart decompression at the time of initiation of central venoarterial extracorporeal membrane oxygenation (VA ECMO) on VA ECMO duration and clinical outcomes in children in a single tertiary ECMO referral center with a large pediatric population from a national referral center for pediatric cardiac surgery. We studied 51 episodes of VA ECMO in a historical cohort of 49 pediatric patients treated between the years 1990 and 2013 in the Paediatric Intensive Care Unit (PICU) of the Royal Children's Hospital, Melbourne. The cases had a variety of diagnoses including congenital cardiac abnormalities, sepsis, myocarditis, and cardiomyopathy. Left heart decompression as an elective treatment or an emergency intervention for left heart distension was effectively achieved by a number of methods, including left atrial venting, blade atrial septostomy, and left ventricular cannulation. Elective left heart decompression was associated with a reduction in time on ECMO (128 h) when compared with emergency decompression (236 h) (P = 0.013). Subgroup analysis showed that ECMO duration was greatest in noncardiac patients (elective 138 h, emergency 295 h; P = 0.02) and in patients who died despite both emergency decompression and ECMO (elective 133 h, emergency 354 h; P = 0.002). As the emergency cases had a lower pH, a higher PaCO2 , and a lower oxygenation index and were treated with a higher mean airway pressure, positive end-expiratory pressure, and respiratory rate prior to receiving VA ECMO, we undertook multivariate linear regression modeling to show that only PaCO2 and the timing of left heart decompression were associated with ECMO duration. However, elective left heart decompression was not associated with a reduction in length of PICU stay, duration of mechanical ventilation, or duration of oxygen therapy. Elective left heart decompression was not associated with improved ECMO survival or survival to PICU discharge

  11. A flexible cure rate model for spatially correlated survival data based on generalized extreme value distribution and Gaussian process priors.

    PubMed

    Li, Dan; Wang, Xia; Dey, Dipak K

    2016-09-01

    Our present work proposes a new survival model in a Bayesian context to analyze right-censored survival data for populations with a surviving fraction, assuming that the log failure time follows a generalized extreme value distribution. Many applications require a more flexible modeling of covariate information than a simple linear or parametric form for all covariate effects. It is also necessary to include the spatial variation in the model, since it is sometimes unexplained by the covariates considered in the analysis. Therefore, the nonlinear covariate effects and the spatial effects are incorporated into the systematic component of our model. Gaussian processes (GPs) provide a natural framework for modeling potentially nonlinear relationship and have recently become extremely powerful in nonlinear regression. Our proposed model adopts a semiparametric Bayesian approach by imposing a GP prior on the nonlinear structure of continuous covariate. With the consideration of data availability and computational complexity, the conditionally autoregressive distribution is placed on the region-specific frailties to handle spatial correlation. The flexibility and gains of our proposed model are illustrated through analyses of simulated data examples as well as a dataset involving a colon cancer clinical trial from the state of Iowa. PMID:27225466

  12. Ocular bubble formation as a method of assessing decompression stress.

    PubMed

    Mekjavić, I B; Campbell, D G; Jaki, P; Dovsak, P A

    1998-01-01

    Tear film bubble formation and ultrasound reflectivity of the lens-vitreous humor compartments were monitored following simulated dives in a hyperbaric chamber. the sensitivity of these methods in determining decompression stress was compared with the results of precordial Doppler ultrasound. In addition, the utility of these diagnostic techniques in testing decompression dive profiles was evaluated. Eleven divers completed two series of chamber dives according to the decompression schedule of the Professional Association of Diving Instructors. The first dive series comprised dives to 70 feet of seawater (fsw) for 15, 29, and 40 min. The second series comprised maximum duration no-stop decompression dives to 40 fsw for 140 min, 70 fsw for 40 min, 90 fsw for 25 min, and 120 fsw for 13 min. Before and immediately after each dive, the following measurements were obtained from each subject: eye surface tear film bubble counts with a slit-lamp microscope, lens and vitreous humor reflectivity using A- and B-mode ophthalmic ultrasonic scan, and precordial Doppler ultrasonic detection of venous gas bubbles. Tear film bubble assessment and ocular scanning ultrasound were observed to be more sensitive in detecting decompression stress than the conventional Doppler ultrasonic surveillance of the precordial region. In contrast to precordial Doppler ultrasonic surveillance, which failed to detect any significant changes in circulating bubbles, tear film bubble formation displayed a dose-response relationship with increasing duration of the 70-fsw dives. Reflectivity changes of the lens-vitreous humor interface were not significant until the no-stop decompression limit was reached. In addition, for each of the no-stop decompression limit dives, increases in the average tear film bubble formation and lens-vitreous humor interface reflectivity were similar. Ocular bubble observations may provide a practical and objective ocular bubble index for analyzing existing decompression

  13. Testing of hypotheses about altitude decompression sickness by statistical analyses

    NASA Technical Reports Server (NTRS)

    Van Liew, H. D.; Burkard, M. E.; Conkin, J.; Powell, M. R. (Principal Investigator)

    1996-01-01

    This communication extends a statistical analysis of forced-descent decompression sickness at altitude in exercising subjects (J Appl Physiol 1994; 76:2726-2734) with a data subset having an additional explanatory variable, rate of ascent. The original explanatory variables for risk-function analysis were environmental pressure of the altitude, duration of exposure, and duration of pure-O2 breathing before exposure; the best fit was consistent with the idea that instantaneous risk increases linearly as altitude exposure continues. Use of the new explanatory variable improved the fit of the smaller data subset, as indicated by log likelihood. Also, with ascent rate accounted for, replacement of the term for linear accrual of instantaneous risk by a term for rise and then decay made a highly significant improvement upon the original model (log likelihood increased by 37 log units). The authors conclude that a more representative data set and removal of the variability attributable to ascent rate allowed the rise-and-decay mechanism, which is expected from theory and observations, to become manifest.

  14. Bubbles Quantified In vivo by Ultrasound Relates to Amount of Gas Detected Post-mortem in Rabbits Decompressed from High Pressure.

    PubMed

    Bernaldo de Quirós, Yara; Møllerløkken, Andreas; Havnes, Marianne B; Brubakk, Alf O; González-Díaz, Oscar; Fernández, Antonio

    2016-01-01

    The pathophysiological mechanism of decompression sickness is not fully understood but there is evidence that it can be caused by intravascular and autochthonous bubbles. Doppler ultrasound at a given circulatory location is used to detect and quantify the presence of intravascular gas bubbles as an indicator of decompression stress. In this manuscript we studied the relationship between presence and quantity of gas bubbles by echosonography of the pulmonary artery of anesthetized, air-breathing New Zealand White rabbits that were compressed and decompressed. Mortality rate, presence, quantity, and distribution of gas bubbles elsewhere in the body was examined postmortem. We found a strong positive relationship between high ultrasound bubble grades in the pulmonary artery, sudden death, and high amount of intra and extra vascular gas bubbles widespread throughout the entire organism. In contrast, animals with lower bubble grades survived for 1 h after decompression until sacrificed, and showed no gas bubbles during dissection. PMID:27493634

  15. Bubbles Quantified In vivo by Ultrasound Relates to Amount of Gas Detected Post-mortem in Rabbits Decompressed from High Pressure

    PubMed Central

    Bernaldo de Quirós, Yara; Møllerløkken, Andreas; Havnes, Marianne B.; Brubakk, Alf O.; González-Díaz, Oscar; Fernández, Antonio

    2016-01-01

    The pathophysiological mechanism of decompression sickness is not fully understood but there is evidence that it can be caused by intravascular and autochthonous bubbles. Doppler ultrasound at a given circulatory location is used to detect and quantify the presence of intravascular gas bubbles as an indicator of decompression stress. In this manuscript we studied the relationship between presence and quantity of gas bubbles by echosonography of the pulmonary artery of anesthetized, air-breathing New Zealand White rabbits that were compressed and decompressed. Mortality rate, presence, quantity, and distribution of gas bubbles elsewhere in the body was examined postmortem. We found a strong positive relationship between high ultrasound bubble grades in the pulmonary artery, sudden death, and high amount of intra and extra vascular gas bubbles widespread throughout the entire organism. In contrast, animals with lower bubble grades survived for 1 h after decompression until sacrificed, and showed no gas bubbles during dissection. PMID:27493634

  16. Improved chest recoil using an adhesive glove device for active compression–decompression CPR in a pediatric manikin model☆

    PubMed Central

    Udassi, Jai P.; Udassi, Sharda; Lamb, Melissa A.; Lamb, Kenneth E.; Theriaque, Douglas W.; Shuster, Jonathan J.; Zaritsky, Arno L.; Haque, Ikram U.

    2013-01-01

    Objective We developed an adhesive glove device (AGD) to perform ACD-CPR in pediatric manikins, hypothesizing that AGD-ACD-CPR provides better chest decompression compared to standard (S)-CPR. Design Split-plot design randomizing 16 subjects to test four manikin-technique models in a crossover fashion to AGD-ACD-CPR vs. S-CPR. Healthcare providers performed 5 min of CPR with 30:2 compression:ventilation ratio in the four manikin models: (1) adolescent; (2) child two-hand; (3) child one-hand; and (4) infant two-thumb. Methods Modified manikins recorded compression pressure (CP), compression depth (CD) and decompression depth (DD). The AGD consisted of a modified oven mitt with an adjustable strap; a Velcro patch was sewn to the palmer aspect. The counter Velcro patch was bonded to the anterior chest wall. For infant CPR, the thumbs of two oven mitts were stitched together with Velcro. Subjects were asked to actively pull up during decompression. Subjects’ heart rate (HR), respiratory rate (RR) and recovery time (RT) for HR/RR to return to baseline were recorded. Subjects were blinded to data recordings. Data (mean ± SEM) were analyzed using a two-tailed paired t-test. Significance was defined qualitatively as P ≤ 0.05. Results Mean decompression depth difference was significantly greater with AGD-ACD-CPR compared to S-CPR; 38–75% of subjects achieved chest decompression to or beyond baseline. AGD-ACD-CPR provided 6–12% fewer chest compressions/minute than S-CPR group. There was no significant difference in CD, CP, HR, RR and RT within each group comparing both techniques. Conclusion A simple, inexpensive glove device for ACD-CPR improved chest decompression with emphasis on active pull in manikins without excessive rescuer fatigue. The clinical implication of fewer compressions/minute in the AGD group needs to be evaluated. PMID:19683849

  17. Magma degassing triggered by static decompression at Kīlauea Volcano, Hawai‘i

    USGS Publications Warehouse

    Poland, Michael P.; Jeff, Sutton A.; Gerlach, Terrence M.

    2009-01-01

    During mid-June 2007, the summit of Kīlauea Volcano, Hawai‘i, deflated rapidly as magma drained from the subsurface to feed an east rift zone intrusion and eruption. Coincident with the deflation, summit SO2 emission rates rose by a factor of four before decaying to background levels over several weeks. We propose that SO2 release was triggered by static decompression caused by magma withdrawal from Kīlauea's shallow summit reservoir. Models of the deflation suggest a pressure drop of 0.5–3 MPa, which is sufficient to trigger exsolution of the observed excess SO2 from a relatively small volume of magma at the modeled source depth beneath Kīlauea's summit. Static decompression may also explain other episodes of deflation accompanied by heightened gas emission, including the precursory phases of Kīlauea's 2008 summit eruption. Hazards associated with unexpected volcanic gas emission argue for increased awareness of magma reservoir pressure fluctuations.

  18. Decompression sickness cases treated with recompression therapy between 1963 and 1998 in Turkey: review of 179 cases.

    PubMed

    Toklu, Akin Savas; Cimsit, Maide; Yildiz, Senol; Uzun, Gunalp; Korpinar, Sefika; Sezer, Hakan; Aktas, Samil

    2014-01-01

    The purpose of this study was to review the cases diagnosed as decompression sickness (DCS) with recompression therapy treament between 1963 and 1998 in Turkey. The records of 179 cases were analyzed for age, gender, type of DCS, presenting signs and symptoms, time to onset of symptoms, time to recompression therapy, recompression table used, total number of treatments and outcomes. The diving depth on the day of injury ranged between 60 and 215 fsw (18 and 65 msw). The symptoms developed during ascent or within 10 minutes after surfacing in 47% of divers and within the first hour in 87% of the divers. The most frequent symptom was sensory loss in the extremities. The dive before the symptoms was a repetitive dive in 50% of the cases and the diagnosis was Type II DCS in 79% of these divers. Most of the divers (84%) received recompression therapy after a delay of more than 12 hours. Healing rate was 68% with the air recompression tables and 86% with the oxygen tables. Repetitive dives were associated with a higher incidence of Type II DCS than single dives (79% and 66%, respectively). The results using recompression tables with oxygen were more successful than the treatment with air tables. PMID:24984316

  19. Spinous Process splitting Laminectomy: Clinical outcome and Radiological analysis of extent of decompression

    PubMed Central

    Srikantha, Umesh

    2015-01-01

    Introduction Spinous process splitting laminectomy (SPSL) is a useful technique in achieving adequate decompression for lumbar canal stenosis, has the advantage of simultaneously decompressing multiple levels and minimising injury to the paraspinal muscles. Some concern has been expressed over the efficacy of this technique in decompressing lateral recesses. This study was undertaken to assess the clinical outcome of SPSL technique and radiologically assess the extent of decompression. Patients and Methods Thirty-nine consecutive patients treated by SPSL for degenerative lumbar spinal stenosis were methodically assessed for demographic data, clinical findings, Pre- and post-op VAS, JOA scores and spinal canal dimensions on imaging. Surgical technique for SPSL is described. Results The mean age of the patients was 66.9 yrs. The mean follow-up was 7.3 months. The mean pre- and post-operative VAS scores were 7.8 and 3.7, respectively. The mean pre- and post-operative JOA scores were 6.3 and 11.2, respectively. The mean JOA recovery rate was 57.3%. 77% of the patients were in the ‘good’ or ‘excellent’ McNab's grades at follow-up. Radiologic results were assessed separately at the 118 levels decompressed by the SPSL technique. The ratio increase for the spinal canal dimensions on post-operative images were as follows – Interfacet distance–116.6%; Effective AP distance–67.6%; Right lateral recess depth–165.1%; Right lateral recess angle–145.5%; Left lateral recess depth–149.3%; Left lateral recess angle–133.6%; Cross-sectional spinal canal area–163.8%. There was no worsening of pre-existing degenerative listhesis or scoliosis in any case. Conclusion SPSL achieves effective central and lateral recess decompression, at the same time minimising injury to the paraspinal muscles thus reducing post-operative pain and aiding in quicker mobilisation and recovery. It is an effective tool to treat multiple level spinal stenosis, especially in elderly

  20. Could some aviation deep vein thrombosis be a form of decompression sickness?

    PubMed

    Buzzacott, Peter; Mollerlokken, Andreas

    2016-10-01

    Aviation deep vein thrombosis is a challenge poorly understood in modern aviation. The aim of the present project was to determine if cabin decompression might favor formation of vascular bubbles in commercial air travelers. Thirty commercial flights were taken. Cabin pressure was noted at take-off and at every minute following, until the pressure stabilized. These time-pressure profiles were imported into the statistics program R and analyzed using the package SCUBA. Greatest pressure differentials between tissues and cabin pressures were estimated for 20, 40, 60, 80 and 120 min half-time compartments. Time to decompress ranged from 11 to 47 min. The greatest drop in cabin pressure was from 1022 to 776 mBar, equivalent to a saturated diver ascending from 2.46 msw depth. Mean pressure drop in flights >2 h duration was 193 mBar, while mean pressure drop in flights <2 h was 165 mBar. The greatest drop in pressure over 1 min was 28 mBar. Over 30 commercial flights it was found that the drop in cabin pressure was commensurate with that found to cause bubbles in man. Both the US Navy and the Royal Navy mandate far slower decompression from states of saturation, being 1.7 and 1.9 mBar/min respectively. The median overall rate of decompression found in this study was 8.5 mBar/min, five times the rate prescribed for USN saturation divers. The tissues associated with hypobaric bubble formation are likely slower than those associated with bounce diving, with 60 min a potentially useful index. PMID:27106903

  1. Microvascular decompression for elderly patients with trigeminal neuralgia.

    PubMed

    Phan, Kevin; Rao, Prashanth J; Dexter, Mark

    2016-07-01

    Microvascular decompression (MVD) has been demonstrated to be an excellent surgical treatment approach in younger patients with trigeminal neuralgia (TN). However, it is not clear whether there are additional morbidity and mortality risks for MVD in the elderly population. We performed a systematic literature review using six electronic databases for studies that compared outcomes for MVD for TN in elderly (cut-off ⩾60, 65, 70years) versus younger populations. Outcomes examined included success rate, deaths, strokes, thromboembolism, meningitis, cranial nerve deficits and cerebrospinal fluid leaks. There were 1524 patients in the elderly cohort and 3488 patients in the younger cohort. There was no significant difference in success rates in elderly versus younger patients (87.5% versus 84.8%; P=0.47). However, recurrence rates were lower in the elderly (11.9% versus 15.6%; P=0.03). The number of deaths in the elderly cohort was higher (0.9% versus 0.1%; P=0.003). Rates of stroke (2.5% versus 1%) and thromboembolism (1.1% versus 0%) were also higher for elderly TN patients. No differences were found for rates of meningitis, cranial nerve deficits or cerebrospinal fluid leak. MVD remains an effective and reasonable strategy in the elderly population. There is evidence to suggest that rates of complications such as death, stroke, and thromboembolism may be significantly higher in the elderly population. The presented results may be useful in the decision-making process for MVD in elderly patients with TN. PMID:26944213

  2. Pseudoaneurysm after arthroscopic subacromial decompression and distal clavicle excision.

    PubMed

    Webb, Brian G; Elliott, Michael P

    2014-06-01

    Arthroscopic shoulder surgery is considered a safe and effective method of treating a variety of shoulder pathologies and is associated with a low complication rate. The type and rate of complications can vary, depending on the procedure, positioning, surgical time, and anesthesia. Fortunately, neurovascular injuries occur infrequently. Numerous studies have described the proximity of neurovascular structures to portals placed in shoulder arthroscopy, in both the beach chair and the lateral decubitus positions. Accurate portal placement is important to avoid damage to adjacent neurovascular structures. Inaccurate placement of portals can lead to inadvertent damage to these structures and create more difficulty with visualization and angle of instrumentation, possibly compromising the success of the procedure. This article describes a 50-year-old man who underwent arthroscopic subacromial decompression and distal clavicle excision for persistent subacromial impingement and acromioclavicular arthritis. During postoperative follow-up, the patient had a small, bulging area located near the anterior portal site. Examination showed a well-healed anterior portal site with a small (approximately 2×2 cm), nontender, immobile mass located within the deep soft tissues just below the anterior portal incision. Ultrasound evaluation showed a pseudoaneurysm of a branch off the axillary artery. The patient underwent successful embolization of the pseudoaneurysm, with complete resolution of symptoms. PMID:24972444

  3. Minimally invasive lumbar decompression-the surgical learning curve.

    PubMed

    Kim, Choll W

    2016-08-01

    Commentary On: Ahn J, Iqbal A, Manning BT, Leblang S, Bohl DD, Mayo BC, et al. Minimally invasive lumbar decompression-the surgical learning curve. Spine J 2016:16:909-16. (in this issue). PMID:27545398

  4. [Theoretical analysis of recompression-based therapies of decompression illness].

    PubMed

    Nikolaev, V P; Sokolov, G M; Komarevtsev, V N

    2011-01-01

    Theoretical analysis is concerned with the benefits of oxygen, air and nitrogen-helium-oxygen recompression schedules used to treat decompression illness in divers. Mathematical modeling of tissue bubbles dynamics during diving shows that one-hour oxygen recompression to 200 kPa does not diminish essentially the size of bubble enclosed in a layer that reduces tenfold the intensity of gas diffusion from bubbles. However, these bubbles dissolve fully in all the body tissues equally after 2-hr. air compression to 800 kPa and ensuing 2-d decompression by the Russian navy tables, and 1.5-hr. N-He-O2 compression to this pressure followed by 5-day decompression. The overriding advantage of the gas mixture recompression is that it obviates the narcotic action of nitrogen at the peak of chamber pressure and does not create dangerous tissue supersaturation and conditions for emergence of large bubbles at the end of decompression. PMID:21970044

  5. Patterns and Variations in Microvascular Decompression for Trigeminal Neuralgia

    PubMed Central

    TODA, Hiroki; GOTO, Masanori; IWASAKI, Koichi

    2015-01-01

    Microvascular decompression (MVD) is a highly effective surgical treatment for trigeminal neuralgia (TN). Although there is little prospective clinical evidence, accumulated observational studies have demonstrated the benefits of MVD for refractory TN. In the current surgical practice of MVD for TN, there have been recognized patterns and variations in surgical anatomy and various decompression techniques. Here we provide a stepwise description of surgical procedures and relevant anatomical characteristics, as well as procedural options. PMID:25925756

  6. Treatment of Peripheral Neuropathy in Leprosy: The Case for Nerve Decompression

    PubMed Central

    Wan, Eric L.; Rivadeneira, Andres F.; Jouvin, Renato Martinez

    2016-01-01

    Summary: Plastic surgery has a tradition of caring for patients with facial deformity and hand deformity related to leprosy. The approach, however, to the progressive deformity and disability related to chronic nerve compression is underappreciated in the world today. A cohort of patients with leprous neuropathy from an indigenous area of leprosy in Ecuador was evaluated for the presence of chronic peripheral nerve compression, and 12 patients were chosen for simultaneous upper and lower extremity, unilateral, nerve decompression at multiple levels along the course of each nerve. The results at 1 year of follow-up show that 6 patients improved into the excellent category and 4 patients improved into the good category for improved function. Based on the early results in this small cohort of patients with leprous neuropathy, an approach to peripheral nerve decompression, encompassing the concept of multiple crush at multiple levels of each nerve, seems to offer optimism to improve upper and lower extremity limb function. Long-term studies with quality-of-life outcomes would be welcome. PMID:27257567

  7. Treatment of Peripheral Neuropathy in Leprosy: The Case for Nerve Decompression.

    PubMed

    Wan, Eric L; Rivadeneira, Andres F; Jouvin, Renato Martinez; Dellon, A Lee

    2016-03-01

    Plastic surgery has a tradition of caring for patients with facial deformity and hand deformity related to leprosy. The approach, however, to the progressive deformity and disability related to chronic nerve compression is underappreciated in the world today. A cohort of patients with leprous neuropathy from an indigenous area of leprosy in Ecuador was evaluated for the presence of chronic peripheral nerve compression, and 12 patients were chosen for simultaneous upper and lower extremity, unilateral, nerve decompression at multiple levels along the course of each nerve. The results at 1 year of follow-up show that 6 patients improved into the excellent category and 4 patients improved into the good category for improved function. Based on the early results in this small cohort of patients with leprous neuropathy, an approach to peripheral nerve decompression, encompassing the concept of multiple crush at multiple levels of each nerve, seems to offer optimism to improve upper and lower extremity limb function. Long-term studies with quality-of-life outcomes would be welcome. PMID:27257567

  8. Temperature acclimation rate of aerobic scope and feeding metabolism in fishes: implications in a thermally extreme future.

    PubMed

    Sandblom, Erik; Gräns, Albin; Axelsson, Michael; Seth, Henrik

    2014-11-01

    Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin (Myoxocephalus scorpius) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations. PMID:25232133

  9. Decompression sickness in breath-hold divers: a review.

    PubMed

    Lemaitre, Frederic; Fahlman, Andreas; Gardette, Bernard; Kohshi, Kiyotaka

    2009-12-01

    Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension. Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to 30-40 m or a single dive to more than 200 m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness. Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms. Modelling attempts have suggested that marine mammals may live permanently with elevated nitrogen concentrations and may be at risk when altering their dive behaviour. In humans, non-pathogenic bubbles have been recorded and symptoms of decompression sickness have been reported after repeated dives to modest depths. The mechanisms implicated in these accidents indicate that repeated breath-hold dives with short surface intervals are factors that predispose to decompression sickness. During deep diving, the effect of pulmonary shunts and/or lung collapse may play a major role in reducing the incidence of decompression sickness in humans and marine mammals. PMID:19967580

  10. Demographic effects of extreme weather events: snow storms, breeding success, and population growth rate in a long-lived Antarctic seabird.

    PubMed

    Descamps, Sébastien; Tarroux, Arnaud; Varpe, Øystein; Yoccoz, Nigel G; Tveraa, Torkild; Lorentsen, Svein-Håkon

    2015-01-01

    Weather extremes are one important element of ongoing climate change, but their impacts are poorly understood because they are, by definition, rare events. If the frequency and severity of extreme weather events increase, there is an urgent need to understand and predict the ecological consequences of such events. In this study, we aimed to quantify the effects of snow storms on nest survival in Antarctic petrels and assess whether snow storms are an important driver of annual breeding success and population growth rate. We used detailed data on daily individual nest survival in a year with frequent and heavy snow storms, and long term data on petrel productivity (i.e., number of chicks produced) at the colony level. Our results indicated that snow storms are an important determinant of nest survival and overall productivity. Snow storm events explained 30% of the daily nest survival within the 2011/2012 season and nearly 30% of the interannual variation in colony productivity in period 1985-2014. Snow storms are a key driver of Antarctic petrel breeding success, and potentially population dynamics. We also found state-dependent effects of snow storms and chicks in poor condition were more likely to die during a snow storm than chicks in good condition. This stresses the importance of considering interactions between individual heterogeneity and extreme weather events to understand both individual and population responses to climate change. PMID:25691959

  11. Demographic effects of extreme weather events: snow storms, breeding success, and population growth rate in a long-lived Antarctic seabird

    PubMed Central

    Descamps, Sébastien; Tarroux, Arnaud; Varpe, Øystein; Yoccoz, Nigel G; Tveraa, Torkild; Lorentsen, Svein-Håkon

    2015-01-01

    Weather extremes are one important element of ongoing climate change, but their impacts are poorly understood because they are, by definition, rare events. If the frequency and severity of extreme weather events increase, there is an urgent need to understand and predict the ecological consequences of such events. In this study, we aimed to quantify the effects of snow storms on nest survival in Antarctic petrels and assess whether snow storms are an important driver of annual breeding success and population growth rate. We used detailed data on daily individual nest survival in a year with frequent and heavy snow storms, and long term data on petrel productivity (i.e., number of chicks produced) at the colony level. Our results indicated that snow storms are an important determinant of nest survival and overall productivity. Snow storm events explained 30% of the daily nest survival within the 2011/2012 season and nearly 30% of the interannual variation in colony productivity in period 1985–2014. Snow storms are a key driver of Antarctic petrel breeding success, and potentially population dynamics. We also found state-dependent effects of snow storms and chicks in poor condition were more likely to die during a snow storm than chicks in good condition. This stresses the importance of considering interactions between individual heterogeneity and extreme weather events to understand both individual and population responses to climate change. PMID:25691959

  12. Surgical options in ICH including decompressive craniectomy.

    PubMed

    Mitchell, Patrick; Gregson, Barbara A; Vindlacheruvu, Raghu R; Mendelow, A David

    2007-10-15

    Intracerebral haemorrhage (ICH) accounts for 15 to 20% of strokes. The condition carries a higher morbidity and mortality than occlusive stroke. Despite considerable research effort, no therapeutic modality either medical or surgical has emerged with clear evidence of benefit other than in rare aneurysmal cases. Intracerebral haemorrhages can be divided into those that arise from pre-existing macroscopic vascular lesions - so called "ictohaemorrhagic lesions", and those that do not; the latter being the commoner. Most of the research that has been done on the benefits of surgery has been in this latter group. Trial data available to date precludes a major benefit from surgical evacuation in a large proportion of cases however there are hypotheses of benefit still under investigation, specifically superficial lobar ICH treated by open surgical evacuation, deeper ICH treated with minimally invasive surgical techniques, and decompressive craniectomy. When an ICH arises from an ictohaemorrhagic lesion, therapy has two goals: to treat the effects of the acute haemorrhage and to prevent a recurrence. Three modalities are available for treating lesions to prevent recurrence: stereotactic radiosurgery, endovascular embolisation, and open surgical resection. As with ICH without an underlying lesion there is no evidence to support surgical removal of the haemorrhage in most cases. An important exception is ICHs arising from intracranial aneurysms where there is good evidence to support evacuation of the haematoma as well as repair of the aneurysm. PMID:17543995

  13. Arthroscopic Decompression for a Giant Meniscal Cyst.

    PubMed

    Ohishi, Tsuyoshi; Suzuki, Daisuke; Matsuyama, Yukihiro

    2016-01-01

    The authors report the case of a giant medial meniscal cyst in an osteoarthritic knee of an 82-year-old woman that was successfully treated with only arthroscopic cyst decompression. The patient noticed a painful mass on the medial side of the right knee that had been gradually growing for 5 years. Magnetic resonance imaging showed an encapsulated large medial cystic mass measuring 80×65×40 mm that was adjacent to the medial meniscus. An accompanying horizontal tear was also detected in the middle and posterior segments of the meniscus. The medial meniscus was resected up to the capsular attachment to create bidirectional flow between the joint and the cyst with arthroscopic surgery. Magnetic resonance imaging performed 14 months postoperatively showed that the cyst had completely disappeared, and no recurrence was observed during a 2-year follow-up period. An excellent result could be obtained by performing limited meniscectomy to create a channel leading to the meniscal cyst, even though the cyst was large. Among previously reported cases of meniscal cysts, this case is the largest to be treated arthroscopically without open excision. PMID:26726987

  14. Bubble nucleation in H2O-CO2 bearing basaltic melts: results of high temperature decompression experiments

    NASA Astrophysics Data System (ADS)

    Le Gall, N.; Pichavant, M.; Burgisser, A.

    2012-12-01

    Previous experiments have shown that mechanisms of basalt degassing are strongly contrasted when gas bubbles are present or when they are absent. Thus, experimental information on the kinetics of bubble nucleation in basaltic melts is needed, and high temperature decompression experiments have been investigated. All experiments used PST-9 basaltic pumice from Stromboli as starting material. The sample was fused in air at 1400°C for 3h and then cylinders (l up to 10mm, d 2.5 and 5mm) were cored. Synthesis experiments were performed to produce the volatile-bearing melts to be used in the decompression experiments. Glass cores, distilled H2O and Ag2C2O4 were loaded in AuPd capsules. Three different H2O/CO2 were introduced, corresponding to XH2Oin=1 (#1: only H2O dissolved in glass), 0.55 (#2: high dissolved H2O/CO2), 0 (#3: low dissolved H2O/CO2). The synthesis experiments were ran at 1200°C during about 40h in an internally heated vessel pressurized with Ar-H2. The synthesized crystal- and bubble-free glasses were cut in 2 parts: one for the decompression experiments and the other for the analysis. Decompression experiments were conducted at a fast rate of 39kPa/s, exceptionally of 77.8kPa/s, at 1200°C from an initial pressure (Pin) of 200MPa and to final pressures (Pf) of 200, 150, 100 and 50MPa. Experiments to 25MPa are in progress. Each run included 3 capsules, corresponding to the 3 XH2Oin conditions of glass synthesis, allowing results for the 3 H2O/CO2 to be directly compared. Charges were rapid-quenched immediately after attainment of Pf. Textures were analyzed by X-ray microtomography, and volatile concentrations and spatial distributions in pre- and post-decompression glasses were determined by FTIR. Pre-decompression glasses have homogeneous volatile contents and distributions. They divide into 3 compositional groups consistent with their XH2Oin conditions of synthesis: group #1 (average H2O content=4.82wt%, average CO2 content=0ppm), group #2 (2.15wt

  15. Submarine rescue decompression procedure from hyperbaric exposures up to 6 bar of absolute pressure in man: effects on bubble formation and pulmonary function.

    PubMed

    Blatteau, Jean-Eric; Hugon, Julien; Castagna, Olivier; Meckler, Cédric; Vallée, Nicolas; Jammes, Yves; Hugon, Michel; Risberg, Jan; Pény, Christophe

    2013-01-01

    Recent advances in submarine rescue systems have allowed a transfer under pressure of crew members being rescued from a disabled submarine. The choice of a safe decompression procedure for pressurised rescuees has been previously discussed, but no schedule has been validated when the internal submarine pressure is significantly increased i.e. exceeding 2.8 bar absolute pressure. This study tested a saturation decompression procedure from hyperbaric exposures up to 6 bar, the maximum operating pressure of the NATO submarine rescue system. The objective was to investigate the incidence of decompression sickness (DCS) and clinical and spirometric indices of pulmonary oxygen toxicity. Two groups were exposed to a Nitrogen-Oxygen atmosphere (pO2 = 0.5 bar) at either 5 bar (N = 14) or 6 bar (N = 12) for 12 h followed by 56 h 40 min resp. 60 h of decompression. When chamber pressure reached 2.5 bar, the subjects breathed oxygen intermittently, otherwise compressed air. Repeated clinical examinations, ultrasound monitoring of venous gas embolism and spirometry were performed during decompression. During exposures to 5 bar, 3 subjects had minor subjective symptoms i.e. sensation of joint discomfort, regressing spontaneously, and after surfacing 2 subjects also experienced joint discomfort disappearing without treatment. Only 3 subjects had detectable intravascular bubbles during decompression (low grades). No bubbles were detected after surfacing. About 40% of subjects felt chest tightness when inspiring deeply during the initial phase of decompression. Precordial burning sensations were reported during oxygen periods. During decompression, vital capacity decreased by about 8% and forced expiratory flow rates decreased significantly. After surfacing, changes in the peripheral airways were still noticed; Lung Diffusion for carbon monoxide was slightly reduced by 1% while vital capacity was normalized. The procedure did not result in serious symptoms of DCS or

  16. Submarine Rescue Decompression Procedure from Hyperbaric Exposures up to 6 Bar of Absolute Pressure in Man: Effects on Bubble Formation and Pulmonary Function

    PubMed Central

    Blatteau, Jean-Eric; Hugon, Julien; Castagna, Olivier; Meckler, Cédric; Vallée, Nicolas; Jammes, Yves; Hugon, Michel; Risberg, Jan; Pény, Christophe

    2013-01-01

    Recent advances in submarine rescue systems have allowed a transfer under pressure of crew members being rescued from a disabled submarine. The choice of a safe decompression procedure for pressurised rescuees has been previously discussed, but no schedule has been validated when the internal submarine pressure is significantly increased i.e. exceeding 2.8 bar absolute pressure. This study tested a saturation decompression procedure from hyperbaric exposures up to 6 bar, the maximum operating pressure of the NATO submarine rescue system. The objective was to investigate the incidence of decompression sickness (DCS) and clinical and spirometric indices of pulmonary oxygen toxicity. Two groups were exposed to a Nitrogen-Oxygen atmosphere (pO2 = 0.5 bar) at either 5 bar (N = 14) or 6 bar (N = 12) for 12 h followed by 56 h 40 min resp. 60 h of decompression. When chamber pressure reached 2.5 bar, the subjects breathed oxygen intermittently, otherwise compressed air. Repeated clinical examinations, ultrasound monitoring of venous gas embolism and spirometry were performed during decompression. During exposures to 5 bar, 3 subjects had minor subjective symptoms i.e. sensation of joint discomfort, regressing spontaneously, and after surfacing 2 subjects also experienced joint discomfort disappearing without treatment. Only 3 subjects had detectable intravascular bubbles during decompression (low grades). No bubbles were detected after surfacing. About 40% of subjects felt chest tightness when inspiring deeply during the initial phase of decompression. Precordial burning sensations were reported during oxygen periods. During decompression, vital capacity decreased by about 8% and forced expiratory flow rates decreased significantly. After surfacing, changes in the peripheral airways were still noticed; Lung Diffusion for carbon monoxide was slightly reduced by 1% while vital capacity was normalized. The procedure did not result in serious symptoms of DCS or

  17. Neurologic decompression sickness following cabin pressure fluctuations at high altitude.

    PubMed

    Auten, Jonathan D; Kuhne, Michael A; Walker, Harlan M; Porter, Henry O

    2010-04-01

    Decompression sickness (DCS) occurs in diving, altitude chamber exposures, and unpressurized or depressurized high-altitude flights. Because DCS takes many forms, in-flight cases may be misinterpreted as hypoxia, hyperventilation, or viral illness, with resulting failure to respond appropriately. In this case, a 28-yr-old male pilot of a single-seat, tactical aircraft experienced 12 rapid pressure fluctuations while flying at 43,000 ft above sea level. He had no symptoms and decided to complete the flight, which required an additional 2 h in the air. Approximately 1 h later he began to experience fatigue, lightheadedness, and confusion, which he interpreted as onset of a viral illness. However, symptoms progressed to visual, cognitive, motor, and sensory degradations and it was with some difficulty that he landed safely at his destination. Neurologic DCS was suspected on initial evaluation by flight line medical personnel because of the delayed onset and symptom progression. He was transferred to a local Emergency Department and noted to have altered mental status, asymmetric motor deficits, and non-dermatomal paresthesias of the upper and lower extremities. Approximately 3.5 h after the incident and 2.5 h after the onset of symptoms he began hyperbaric oxygen therapy. He received partial relief at 30 min of the Navy DiveTable 6 and full resolution at 90 min; there were no recurrent symptoms at a 1-yr follow-up. This case highlights the importance of early recognition of in-flight DCS symptoms and landing as soon as possible rather than as soon as practical in all likely scenarios. PMID:20377149

  18. Extremely high-rate, uniform dissolution of alloy C-22 in anhydrous organic solutions at room temperature

    DOE PAGESBeta

    Schindelholz, Eric J.; Christie, Michael A.; Allwein, Shawn P.; Kelly, Robert G.

    2016-06-21

    During routine pharmaceutical development and scale-up work, severe corrosion of a Hastelloy Alloy C-22 filter dryer was observed after single, short (several hours) contact with the product slurry at room temperature. Initial investigations showed that the presence of both 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and HCl was sufficient in an acetonitrile solution to cause rapid corrosion of C-22. More detailed mass loss studies showed initial corrosion rates exceeding25 mm/year that then decreased over several hours to steady state rates of 3-5 mm/year. The corrosion was highly uniform. Electrochemical measurements demonstrated that although C-22 is spontaneously passive in acetonitrile solution, the presence of HClmore » leads to the development of a transpassive region. Furthermore, DDQ is a sufficiently strong oxidizer, particularly in acidic solutions, to polarize the C-22 well into the transpassive region, leading to the observed high corrosion rates.« less

  19. Mesoporous CNT@TiO2-C nanocable with extremely durable high rate capability for lithium-ion battery anodes.

    PubMed

    Wang, Bin; Xin, Huolin; Li, Xiaodong; Cheng, Jianli; Yang, Guangcheng; Nie, Fude

    2014-01-01

    A well-designed nanostructure CNT@TiO2-C with fine anatase TiO2 particle (< 8 nm), good electronic conducting network (inner CNT core and outer carbon layer), and mesoporous structure was prepared by a simple and green one-pot hydrothermal reaction. The utilization of glucose in the hydrothermal process not only solves the interfacial incompatibility between CNTs and titanate sol and controls the nucleation and growth of TiO2 particles, but also introduces a uniform, glucose-derived, carbon-layer on the TiO2 particles. The nanosized TiO2 particle, high conducting network, and interconnected nanopores of the CNT@TiO2-C nanocable greatly improve its electrochemical performances, especially rate capability. The CNT@TiO2-C nanocables show remarkable rate capability with reversible charge capacity of 297, 240, 210,178 and 127 mAh g(-1) at 1C, 5C, 10C, 20C and 50C, respectively, as well as excellent high rate cycling stability with capacity retention of 87% after 2000 cycles at 50C. PMID:24429419

  20. A Novel Martensitic Creep-Resistant Steel Strengthened by MX Carbonitrides with Extremely Low Coarsening Rates: Design and Characterization

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Ma, Wenjie; Yan, Wei; Yang, Ke; Toda, Yoshiaki; van der Zwaag, Sybrand; Xu, Wei

    2016-07-01

    A general computational alloy design approach, based on thermodynamics and thermokinetics and coupled with a genetic algorithm optimization routine, was applied to the design of novel creep martensitic resistant steels. The optimal alloy suggested by the model has a high density of barely coarsening MX carbonitride precipitates. The model yielded precise values for the concentrations of the 10 alloying elements considered. The model alloy was produced on a 10 kg lab scale. Samples of the new alloy of one of the best commercial martensitic steels on the market P92 were subjected to a high aging temperature of 923 K (650 °C) for times up to 1000 hours. The microstructure of the new alloy in the as-produced state as well as after 1000 hours exposure has all the intended features as predicted by the model. The coarsening rate of the MX rate carbonitrides was substantially lower than that of the precipitates in the P92 steel. The very low coarsening rate explains the superior hardness at very long exposure times.

  1. Effects of Decompression Treatment for Controlling the Powderpost Beetle, Lyctus africanus Lesne, (Coleoptera: Lyctinae).

    PubMed

    Nakai, Kazushi; Hiraku, Tatsuya; Fujimoto, Izumi; Yoshimura, Tsuyoshi

    2016-01-01

    The efficacy of decompression treatment as a non-destructive method to control larvae of the powderpost beetle, Lyctus africanus Lesne, was evaluated in the laboratory using various combinations of two pressure levels, 1.1 kPa and 40 kPa, and three temperature levels, 20, 25, and 40 °C. Larval mortality generally depended on weight reduction while decreases in the oxygen level had relatively little effect. The lower pressure, 1.1 kPa, significantly affected mortality, and no larvae survived after 12 h of this pressure treatment, at 25 °C. The average body weight was reduced with treatment time and temperature, and the reduction rate at 25 °C was higher than that at the lower temperature, 20 °C. Effects on larvae of the higher pressure treatment, 40 kPa, with a CO₂ gas purge, were tested to determine the feasibility of decompression treatment in the manufacturing process. Although higher pressure resulted in low mortality, the body weight was dramatically decreased using the CO₂ purge. These results present important information on the possibility of using decompression treatment for wood products. PMID:27429007

  2. Evidence for the initiation of decompression sickness by exposure to intense underwater sound.

    PubMed

    Tal, Dror; Shachar-Bener, Hofit; Hershkovitz, Dov; Arieli, Yehuda; Shupak, Avi

    2015-09-01

    Mass stranding of cetaceans (whales and dolphins), in close association with the activity of naval sonar systems, has been reported on numerous occasions. Necropsy showed bubble-associated lesions similar to those described in human decompression sickness (DCS). We examined the hypothesis that exposure to underwater sound may potentiate DCS. Rats were subjected to immersion and simulated dives with and without simultaneous acoustic transmissions at pressure levels and frequencies of 204 dB/8 kHz and 183.3 dB/15 kHz. DCS severity was assessed using the rotating wheel method. Recording of somatosensory evoked potentials (SSEPs) was employed under general anesthesia as an electrophysiological measure of neurologic insult. A significantly higher rate of decompression sickness was found among animals exposed to the 204-dB/8-kHz sound field. Significantly higher pathological SSEPs scores were noted for both underwater sound protocols. Pathological SSEPs scores in animals immersed during the acoustic transmissions, but without changes in ambient pressure, were comparable to those observed in animals exposed to the dive profile. The results demonstrate induction of neurological damage by intense underwater sound during immersion, with a further deleterious effect when this was combined with decompression stress. The study outcome has potential implications for human diving safety and may provide an explanation for the mass stranding of cetaceans purportedly associated with sonar activity. PMID:26133802

  3. Analysis of the Risk Factors Affecting the Surgical Site Infection after Cranioplasty Following Decompressive Craniectomy

    PubMed Central

    Kim, Jin Seong; Kim, Sung Kwon; Park, Hyun; Kang, Dong-Ho; Lee, Chul-Hee; Hwang, Soo-Hyun; Jung, Jin-Myung; Han, Jong-Woo

    2015-01-01

    Objective The risk factors for surgical site infections (SSIs) after cranioplasty following decompressive craniectomy remain unclear. The goal of this study was to analyze the risk factors related to developing SSIs after cranioplasty and to suggest valuable predictors. Methods A retrospective review was conducted of patients who underwent cranioplasty following decompressive craniectomy at our institution from January 2011 to December 2014, a total of 78 patients who underwent 78 cranioplasties. Univariate and multivariate logistic regression analyses were carried out to determine possible risk factors related to developing SSIs. We analyzed both patient-specific and surgery-specific factors. Results The overall rate of SSIs was 9.0% (7/78). SSIs after cranioplasty were significantly related to being female, having the primary etiology of traumatic brain injury (TBI) and having had a bilateral cranioplasty in the univariate analysis. Multivariate logistic regression analysis showed that being female [odds ratio (OR) 5.98, p=0.000] and having had a bilateral cranioplasty (OR 4.00, p=0.001) significantly increased the risk of SSIs. Conclusion Based on our data, cranioplasty following decompressive craniectomy is associated with a high incidence of SSI. Being female, having a primary etiology of TBI and having had a bilateral cranioplasty may be risk factors for surgical site infections after cranioplasty. PMID:27169073

  4. Evidence for the initiation of decompression sickness by exposure to intense underwater sound

    PubMed Central

    Tal, Dror; Shachar-Bener, Hofit; Hershkovitz, Dov; Arieli, Yehuda

    2015-01-01

    Mass stranding of cetaceans (whales and dolphins), in close association with the activity of naval sonar systems, has been reported on numerous occasions. Necropsy showed bubble-associated lesions similar to those described in human decompression sickness (DCS). We examined the hypothesis that exposure to underwater sound may potentiate DCS. Rats were subjected to immersion and simulated dives with and without simultaneous acoustic transmissions at pressure levels and frequencies of 204 dB/8 kHz and 183.3 dB/15 kHz. DCS severity was assessed using the rotating wheel method. Recording of somatosensory evoked potentials (SSEPs) was employed under general anesthesia as an electrophysiological measure of neurologic insult. A significantly higher rate of decompression sickness was found among animals exposed to the 204-dB/8-kHz sound field. Significantly higher pathological SSEPs scores were noted for both underwater sound protocols. Pathological SSEPs scores in animals immersed during the acoustic transmissions, but without changes in ambient pressure, were comparable to those observed in animals exposed to the dive profile. The results demonstrate induction of neurological damage by intense underwater sound during immersion, with a further deleterious effect when this was combined with decompression stress. The study outcome has potential implications for human diving safety and may provide an explanation for the mass stranding of cetaceans purportedly associated with sonar activity. PMID:26133802

  5. Clinical therapeutic effects of anterior decompression on spinal osteoporotic fracture and inflammatory cytokines

    PubMed Central

    Liao, Qi; Liu, Shi-Qing; Ming, Jiang-Hua; Chen, Qing; Zhao, Qi; Yang, Yue

    2014-01-01

    Objective: To evaluate the clinical therapeutic effects of anterior decompression on spinal osteoporotic fracture and inflammatory cytokines. Methods: A total of 140 patients with spinal osteoporotic fracture were selected and randomly divided into a treatment group and a control group (n=70). The control group was treated by central corpectomy, and the control group was treated by anterior decompression. Results: The rate of excellent and good outcomes in the treatment group was 94.3%, and that of the control group was 78.6%, which differed significantly (P<0.05). Cobb angle and cord occupancy in the spinal canal of both groups significantly decreased (P<0.05), while height ratio of the injured vertebral body significantly increased (P<0.05). Meanwhile, there were statistically significant inter-group differences (P<0.05). During the three-month follow-up period, the treatment group was significantly less prone to complications such as superficial infection, spinal instability and screw breakage compared with the control group (P<0.05). The postoperative serum MMP-3 and IL-6 levels of both groups significantly decreased compared with those before surgeries (P<0.05), with statistically significant inter-group differences (P<0.05). Conclusion: Compared with central corpectomy, anterior decompression exerted better effects on spinal osteoporotic fracture by improving the prognosis and stabilizing the spine safely, which may be associated with the effectively reduced serum MMP-3 and IL-6 levels. PMID:25225501

  6. The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis.

    PubMed

    Bai, Yan; Selvaraj, Nandakumar; Petersen, Kyle; Mahon, Richard; Cronin, William A; White, Joseph; Brink, Peter R; Chon, Ki H

    2013-10-01

    Methods to predict onset of cardiopulmonary (CP) decompression sickness (DCS) would be of great benefit to clinicians caring for stricken divers. Principal dynamic mode (PDM) analysis of the electrocardiogram has been shown to provide accurate separation of the sympathetic and parasympathetic tone dynamics. Nine swine (Sus scrofa) underwent a 15-h saturation dive at 184 kPa (60 ft. of saltwater) in a hyperbaric chamber followed by dropout decompression, whereas six swine, used as a control, underwent a 15-h saturation dive at 15 kPa (5 ft. of saltwater). Noninvasive electrocardiograms were recorded throughout the experiment and autonomic nervous system dynamics were evaluated by heart rate series analysis using power spectral density (PSD) and PDM methods. We observed a significant increase in the sympathetic and parasympathetic tones using the PDM method on average 20 min before DCS onset following a sudden induction of decompression. Parasympathetic activities remained elevated, but the sympathetic modulation was significantly reduced at onset of cutis and CP DCS signs, as reported by a trained observer. Similar nonsignificant observations occurred during PSD analysis. PDM observations contrast with previous work showing that neurological DCS resulted in a >50% reduction in both sympathetic and parasympathetic tone. Therefore, tracking dynamics of the parasympathetic tones via the PDM method may allow discrimination between CP DCS and neurological DCS, and this significant increase in parasympathetic tone has potential use as a marker for early diagnosis of CP DCS. PMID:23883677

  7. Pediatric and adult vision restoration after optic nerve sheath decompression for idiopathic intracranial hypertension.

    PubMed

    Bersani, Thomas A; Meeker, Austin R; Sismanis, Dimitrios N; Carruth, Bryant P

    2016-06-01

    To compare presentations of idiopathic intracranial hypertension and efficacy of optic nerve sheath decompression between adult and pediatric patients, a retrospective cohort study was completed All idiopathic intracranial hypertension patients undergoing optic nerve sheath decompression by one surgeon between 1991 and 2012 were included. Pre-operative and post-operative visual fields, visual acuity, color vision, and optic nerve appearance were compared between adult and pediatric (<18 years) populations. Outcome measures included percentage of patients with complications or requiring subsequent interventions. Thirty-one adults (46 eyes) and eleven pediatric patients (18 eyes) underwent optic nerve sheath decompression for vision loss from idiopathic intracranial hypertension. Mean deviation on visual field, visual acuity, color vision, and optic nerve appearance significantly improved across all subjects. Pre-operative mean deviation was significantly worse in children compared to adults (p=0.043); there was no difference in mean deviation post-operatively (p=0.838). Significantly more pediatric eyes (6) presented with light perception only or no light perception than adult eyes (0) (p=0.001). Pre-operative color vision performance in children (19%) was significantly worse than in adults (46%) (p=0.026). Percentage of patients with complications or requiring subsequent interventions did not differ between groups. The consistent improvement after surgery and low rate of complications suggest optic nerve sheath decompression is safe and effective in managing vision loss due to adult and pediatric idiopathic intracranial hypertension. Given the advanced pre-operative visual deficits seen in children, one might consider a higher index of suspicion in diagnosing, and earlier surgical intervention in treating pediatric idiopathic intracranial hypertension. PMID:27163674

  8. Lower extremity soft tissue reconstruction and amputation rates in patients with open tibial fractures in Sweden during 1998–2010

    PubMed Central

    2014-01-01

    Background The rates of soft tissue reconstruction and amputation after open tibial fractures have not been studied on a national perspective. We aimed to determine the frequency of soft tissue coverage after open tibial fracture as well as primary and secondary amputation rates. Methods Data on all patients (> = 15 years) admitted to hospital with open tibial fractures were extracted from the Swedish National Patient Register (1998–2010). All surgical procedures, re-admissions, and mechanisms of injury were analysed accordingly. The risk of amputation was calculated using logistic regression (adjusted for age, sex, mechanism of injury, reconstructive surgery and fixation method). The mean follow-up time was 6 (SD 3.8) years. Results Of 3,777 patients, 342 patients underwent soft tissue reconstructive surgery. In total, there were 125 amputations. Among patients with no reconstructive surgery, 2% (n = 68 patients) underwent amputation. In an adjusted analysis, patients older than 70 years (OR = 2.7, 95%, CI = 1.1-6) and those who underwent reconstructive surgery (OR = 3.1, 95% CI = 1.6-5.8) showed higher risk for amputation. Fixations other than intramedullary nailing (plate, external fixation, closed reduction and combination) as the only method were associated with a significant higher risk for amputation (OR 5.1-14.4). Reconstruction within 72 hours (3 days) showed better results than reconstruction between 4–90 days (p = 0.04). Conclusions The rate of amputations after open tibial fractures is low (3.6%). There is a higher risk for amputations with age above 70 (in contrast: male sex and tissue reconstruction are rather indicators for more severe soft tissue injuries). Only a small proportion of open tibial fractures need soft tissue reconstructive surgery. Reconstruction with free or pedicled flap should be performed within 72 hours whenever possible. PMID:25323662

  9. Improved image decompression for reduced transform coding artifacts

    NASA Technical Reports Server (NTRS)

    Orourke, Thomas P.; Stevenson, Robert L.

    1994-01-01

    The perceived quality of images reconstructed from low bit rate compression is severely degraded by the appearance of transform coding artifacts. This paper proposes a method for producing higher quality reconstructed images based on a stochastic model for the image data. Quantization (scalar or vector) partitions the transform coefficient space and maps all points in a partition cell to a representative reconstruction point, usually taken as the centroid of the cell. The proposed image estimation technique selects the reconstruction point within the quantization partition cell which results in a reconstructed image which best fits a non-Gaussian Markov random field (MRF) image model. This approach results in a convex constrained optimization problem which can be solved iteratively. At each iteration, the gradient projection method is used to update the estimate based on the image model. In the transform domain, the resulting coefficient reconstruction points are projected to the particular quantization partition cells defined by the compressed image. Experimental results will be shown for images compressed using scalar quantization of block DCT and using vector quantization of subband wavelet transform. The proposed image decompression provides a reconstructed image with reduced visibility of transform coding artifacts and superior perceived quality.

  10. Efficacy of percutaneous laser disc decompression on lumbar spinal stenosis.

    PubMed

    Ren, Longxi; Han, Zhengfeng; Zhang, Jianhua; Zhang, Tongtong; Yin, Jian; Liang, Xibin; Guo, Han; Zeng, Yanjun

    2014-05-01

    The objective of this study is to observe the effect of percutaneous laser disc decompression (PLDD) on lumbar spinal stenosis (LSS). Thirty-two LSS patients were treated using pulsed Nd: YAG laser, of which 21 cases (11 males and 10 females with an average age of 64 years old) were followed up for 2 years. All of the 21 patients had intermittent claudication with negative straight leg raising test results. Fifteen patients suffered from anterior central disc herniation which often compressed the cauda equina but seldom compressed the posterior part; six patients suffered from posterior ligamentum flavum hypertrophy which often compressed the cauda equina but seldom compressed the anterior part. The efficacy was evaluated 1, 3, 6, 12 and 24 months after surgery on 21 patients using the performance evaluation criteria of the lumbago treatment by the Japanese Orthopaedic Association (JOA 29 scores). The fineness (i.e. excellent and good treatment outcome) rate 1, 3, 6, 12 and 24 months after the operation were 46.7%, 66.7%, 66.7%, 66.7% and 66.7%, respectively, in patients with severe anterior compression and 16.7%, 33.3%, 33.3%, 33.3% and 33.3%, respectively, in patients with severe posterior compression. PLDD had certain positive efficacy on the treatment of lumbar spinal stenosis, which was more significant on LSS dominated by the anterior compression than that by the posterior compression. PMID:23996073

  11. Population structure and growth rates at biogeographic extremes: a case study of the common cockle, Cerastoderma edule (L.) in the Barents Sea.

    PubMed

    Genelt-Yanovskiy, Evgeny; Poloskin, Alexey; Granovitch, Andrei; Nazarova, Sophia; Strelkov, Petr

    2010-01-01

    A descriptive study of population structure, growth rates and shell morphometry was conducted on nine intertidal populations of the infaunal bivalve Cerastoderma edule in the Murmansk coast of the Barents Sea. Year-to-year population dynamics was analyzed during 2002-2006 on a tidal flat Dalniy Plaj (eastern Murmansk coast). The region constitutes the northern extremes of C. edule range where populations occupied the middle to low intertidal zone and were characterized by low densities. The distribution of age groups and unstable age structure across years in the cockle populations suggest irregular recruitment. Growth rates and shell morphometry showed little variation across the populations studied, and there were no gradient changes from the west to the east parts of Murmansk coast. PMID:20347100

  12. Aerobic stabilization of biological sludge characterized by an extremely low decay rate: modeling, identifiability analysis and parameter estimation.

    PubMed

    Martínez-García, C G; Olguín, M T; Fall, C

    2014-08-01

    Aerobic digestion batch tests were run on a sludge model that contained only two fractions, the heterotrophic biomass (XH) and its endogenous residue (XP). The objective was to describe the stabilization of the sludge and estimate the endogenous decay parameters. Modeling was performed with Aquasim, based on long-term data of volatile suspended solids and chemical oxygen demand (VSS, COD). Sensitivity analyses were carried out to determine the conditions for unique identifiability of the parameters. Importantly, it was found that the COD/VSS ratio of the endogenous residues (1.06) was significantly lower than for the active biomass fraction (1.48). The decay rate constant of the studied sludge (low bH, 0.025 d(-1)) was one-tenth that usually observed (0.2d(-1)), which has two main practical significances. Digestion time required is much more long; also the oxygen uptake rate might be <1.5 mg O₂/gTSSh (biosolids standards), without there being significant decline in the biomass. PMID:24907570

  13. Monotherapeutic High-Dose-Rate Brachytherapy for Prostate Cancer: Five-Year Results of an Extreme Hypofractionation Regimen With 54 Gy in Nine Fractions

    SciTech Connect

    Yoshioka, Yasuo; Konishi, Koji; Sumida, Iori; Takahashi, Yutaka; Isohashi, Fumiaki; Ogata, Toshiyuki; Koizumi, Masahiko; Yamazaki, Hideya; Nonomura, Norio; Okuyama, Akihiko; Inoue, Takehiro

    2011-06-01

    Purpose: To evaluate an extreme hypofractionation regimen with 54 Gy in nine fractions provided by high-dose-rate (HDR) brachytherapy as monotherapy for prostate cancer by reporting 5-year clinical results. Methods and Materials: Between 1996 and 2005, 112 patients with localized prostate cancer were treated with HDR brachytherapy without external beam radiotherapy. Of the 112 patients, 15 were considered low risk, 29 intermediate risk, and 68 as high risk. The prescribed dose was uniformly 54 Gy in nine fractions within 5 days. Of the 112 patients, 94 also received hormonal therapy. The median follow-up time was 5.4 years. Results: All the patients safely completed the treatment regimen. The 5-year prostate-specific antigen (PSA) failure-free, local control, disease-free survival, and overall survival rate was 83%, 97%, 87%, and 96%, respectively. The 5-year PSA failure-free rate for low-, intermediate-, and high-risk patients was 85% (95% confidence interval, 66-100%), 93% (95% confidence interval, 83-100%), and 79% (95% confidence interval, 69-89%), respectively. The significant prognostic factors for PSA failure were the initial PSA level (p = .029) and younger age (p = .019). The maximal toxicities observed were Grade 3 using the Common Terminology Criteria for Adverse Events, version 3.0, for both acute and late toxicity (6 and 3 patients had acute and late Grade 3 toxicity, respectively). Late Grade 2 toxicity was observed in 13 patients. Conclusion: Monotherapeutic HDR brachytherapy with an extreme hypofractionation regimen of 54 Gy in nine fractions associated with hormonal therapy was feasible, and its toxicity was acceptable. The interim tumor control rate at a median 5.4 years was promising, even for patients with locally advanced disease. This dose-fractionation scheme might be referred to by other terms, such as stereotactic body radiotherapy. Studies with longer follow-up periods and from multiple institutions are needed to confirm the efficacy of

  14. Treatment of lumbar disc herniation by percutaneous laser disc decompression (PLDD) and modified PLDD

    NASA Astrophysics Data System (ADS)

    Chi, Xiao fei; Li, Hong zhi; Wu, Ru zhou; Sui, Yun xian

    2005-07-01

    Objective: To study the micro-invasive operative method and to compare the effect of treatment of PLDD and modified PLDD for Lumbar Disc Herniation. Method: Vaporized part of the nucleus pulposus in single or multiple point after acupuncture into lumbar disc, to reach the purpose of the decompression of the lumbar disc. Result: Among the 19 cases of the regular PLDD group, the excellent and good rate was 63.2%, and among the 40 cases of the modified PLDD group, the excellent and good rate was 82.5%. Conclusion: The modified PLDD has good effect on the treatment for lumbar disc herniation.

  15. Decompression induced bubble dynamics on ex vivo fat and muscle tissue surfaces with a new experimental set up.

    PubMed

    Papadopoulou, Virginie; Evgenidis, Sotiris; Eckersley, Robert J; Mesimeris, Thodoris; Balestra, Costantino; Kostoglou, Margaritis; Tang, Meng-Xing; Karapantsios, Thodoris D

    2015-05-01

    Vascular gas bubbles are routinely observed after scuba dives using ultrasound imaging, however the precise formation mechanism and site of these bubbles are still debated and growth from decompression in vivo has not been extensively studied, due in part to imaging difficulties. An experimental set-up was developed for optical recording of bubble growth and density on tissue surface area during hyperbaric decompression. Muscle and fat tissues (rabbits, ex vivo) were covered with nitrogen saturated distilled water and decompression experiments performed, from 3 to 0bar, at a rate of 1bar/min. Pictures were automatically acquired every 5s from the start of the decompression for 1h with a resolution of 1.75μm. A custom MatLab analysis code implementing a circular Hough transform was written and shown to be able to track bubble growth sequences including bubble center, radius, contact line and contact angles over time. Bubble density, nucleation threshold and detachment size, as well as coalescence behavior, were shown significantly different for muscle and fat tissues surfaces, whereas growth rates after a critical size were governed by diffusion as expected. Heterogeneous nucleation was observed from preferential sites on the tissue substrate, where the bubbles grow, detach and new bubbles form in turn. No new nucleation sites were observed after the first 10min post decompression start so bubble density did not vary after this point in the experiment. In addition, a competition for dissolved gas between adjacent multiple bubbles was demonstrated in increased delay times as well as slower growth rates for non-isolated bubbles. PMID:25835147

  16. Joint pain and Doppler-detectable bubbles in altitude (Hypobaric) decompression

    NASA Technical Reports Server (NTRS)

    Powell, Michael R.

    1993-01-01

    The observation that altitude decompression sickness (DCS) is associated with pain in the lower extremities is not new, although it is not a consistent finding. DCS in divers is generally in the upper body, an effect often attributed to non-loading of the body while immersed. In caisson workers, DCS is reported more in the lower extremities. Surprisingly, many researchers do not mention the location of DCS joint pain, apparently considering it to be random. This is not the case for the tissue ratios encountered in studying decompression associated with simulated EVA. In NASA/JSC tests, altitude DCS generally presented first in either the ankle, knee, or hip (83 percent = 73/88). There was a definite statistical relation between the maximum Spencer precordial Doppler Grade and the incidence of DCS in the extremity, although this is not meant to imply a casual relation between circulating gas bubbles and joint pain. The risk of DCS with Grade 4 was considerably higher than that of Grades 0 to 3. The DCS risk was independent of the 'tissue ratio.' There was a predominance of lower extremity DCS even when exercise was performed with the upper body. The reason for these locations we hypothesize to be attributed to the formation of tissue gas micronuclei from kinetic and tensile forces (stress-assisted nucleation) and are the result of the individuals ambulating in a 1g environment. Additionally, since these showers of Doppler bubbles can persist for hours, it is difficult to imagine that they are emanating solely from tendons and ligaments, the supposed site of joint pain. This follows from Henry's law linking the volume of joint tissue (the solvent) and the solubility coefficient of inert gas; there is volumetrically insufficient connective tissue to produce the prolonged release of gas bubbles. If gas bubbles are spawned and released from connective tissue, their volume is increased by those from muscle tissue. Therefore, the nexus between Doppler-detectable gas

  17. Decompression alone versus decompression with limited fusion for treatment of degenerative lumbar scoliosis in the elderly patient

    PubMed Central

    Daubs, Michael D.; Lenke, Lawrence G.; Bridwell, Keith H.; Cheh, Gene; Kim, Yongjung J.; Stobbs, Georgia

    2012-01-01

    Study design: Retrospective cohort study. Objective: To analyze the surgical results of a group of patients older than 65 years treated for mild degenerative lumbar scoliosis (<30°) with stenosis, treated with decompression alone or decompression and limited fusion. Methods: We evaluated 55 patients, all older than 65 years from our prospectively collected database with mild degenerative scoliosis (<30°) and stenosis who underwent surgery. Laminectomy alone was performed in 16 patients, and laminectomy and limited fusion in 39 patients. Mean follow-up was 4.6 years in the decompression group and 5.0 years in the fusion group. Clinical results were graded by patients' self-reported satisfaction and length of symptom-free period to recurrence. Results: In the decompression alone group, 6 (37%) of 16 patients developed recurrent stenosis at the previously decompressed level and five developed recurrence within 6 months postoperatively versus the decompression and fusion group where 3 (8%) of 39 (P = .0476) developed symptomatic stenosis supra adjacent to the fusion. Of 16 patients in the decompression alone group, 12 (75%) had recurrence of symptoms by the 5-year follow-up period versus only 14 (36%) patients in the decompression and fusion group (P = .016). Adjacent segment degenerative changes were common in the fusion group, but only 7% developed symptomatic stenosis. Conclusions: Decompression with limited fusion prevents early return of stenotic symptoms compared with decompression alone in the setting of mild degenerative scoliosis (<30°) and symptomatic stenosis in patients 65 years and older. Final class of evidence–prognosis Study design  RCT  Cohort •  Case control  Case series Methods  Concealed allocation (RCT)  Intention to treat (RCT)  Blinded/independent evaluation of primary outcome  F/U ≥ 85% •  Adequate sample size  Control for confounding Overall class of evidence III The definiton of the different classes of

  18. Delayed Recompression for Decompression Sickness: Retrospective Analysis

    PubMed Central

    Hadanny, Amir; Fishlev, Gregori; Bechor, Yair; Bergan, Jacob; Friedman, Mony; Maliar, Amit; Efrati, Shai

    2015-01-01

    Introduction Most cases of decompression sickness (DCS) occur soon after surfacing, with 98% within 24 hours. Recompression using hyperbaric chamber should be administrated as soon as feasible in order to decrease bubble size and avoid further tissue injury. Unfortunately, there may be a significant time delay from surfacing to recompression. The time beyond which hyperbaric treatment is non effective is unclear. The aims of the study were first to evaluate the effect of delayed hyperbaric treatment, initiated more than 48h after surfacing for DCS and second, to evaluate the different treatment protocols. Methods From January 2000 to February 2014, 76 divers had delayed hyperbaric treatment (≥48h) for DCS in the Sagol center for Hyperbaric medicine and Research, Assaf-Harofeh Medical Center, Israel. Data were collected from their medical records and compared to data of 128 patients treated earlier than 48h after surfacing at the same hyperbaric institute. Results There was no significant difference, as to any of the baseline characteristics, between the delayed and early treatment groups. With respect to treatment results, at the delayed treatment divers, complete recovery was achieved in 76% of the divers, partial recovery in 17.1% and no improvement in 6.6%. Similar results were achieved when treatment started early, where 78% of the divers had complete recovery, 15.6% partial recovery and 6.2% no recovery. Delayed hyperbaric treatment using US Navy Table 6 protocol trended toward a better clinical outcome yet not statistically significant (OR=2.786, CI95%[0.896-8.66], p=0.07) compared to standard hyperbaric oxygen therapy of 90 minutes at 2 ATA, irrespective of the symptoms severity at presentation. Conclusions Late recompression for DCS, 48 hours or more after surfacing, has clinical value and when applied can achieve complete recovery in 76% of the divers. It seems that the preferred hyperbaric treatment protocol should be based on US Navy Table 6. PMID

  19. Influence of decompression sickness on vasomotion of isolated rat vessels.

    PubMed

    Mazur, A; Lambrechts, K; Buzzacott, P; Wang, Q; Belhomme, M; Theron, M; Mansourati, J; Guerrero, F

    2014-06-01

    Several studies have demonstrated that endothelial function is impaired following a dive even without decompression sickness. During this study we determined the effect of decompression sickness on endothelium-dependent and independent vasoreactivity. For this purpose twenty-seven male Sprague-Dawley rats were submitted to a simulated dive up to 1,000 kPa absolute pressure and divided into 3 groups: safe diving without decompression sickness or dives provoking mild or severe sickness. A fourth control group remained at atmospheric pressure. Endothelium-dependent and independent vasomotion was assessed ex vivo by measuring isometric tension in rings of abdominal aorta and mesenteric arteries. Dose-response curves were obtained with phenylephrine, acetylcholine and sodium nitroprusside. Acetylcholine-induced relaxation was measured in the presence of L-NAME, indometacin or both of them at once.Contraction was significantly decreased after each protocol compared with the control rats. Additionally, the response in animals from the severe group was significantly different from that of the safe and mild groups. Dose response curves for acetylcholine alone and in the presence of inhibitors remained unchanged. We did not observe differences in endothelium-dependent vasodilation after diving or in the presence of decompression sickness. Contractile response to phenylephrine was progressively impaired with increased decompression stress. These results may indicate smooth muscle injury. PMID:24258471

  20. Decompression sickness during construction of the Great Belt Tunnel, Denmark.

    PubMed

    Andersen, H L

    2002-01-01

    Thirteen cases of decompression sickness (DCS) occurred during the construction of the 8-km long railway tunnel under the Great Belt in Denmark between January 1992 and February 1996. 320 compressed air workers were subjected to 9018 pressure exposures in four tunnel boring machines. Overall DCS incidence was 0.14%. Working pressures ranged between 0.25 bar (1.25 atm abs or 126.3 kPa) and 2.95 bar (3.91 atm abs or 396.3 kPa) and working times ranged between 2 minutes and 339 minutes. During the first 1798 pressure exposures 7 DCS cases occurred using French air decompression tables from 1974. The following 7220 exposures were then decompressed in accordance with the newly issued French air decompression tables of 1992. After changing schedules 6 DCS cases occurred and DCS incidence was reduced to 0.08%. Two of the first seven DCS cases had permanent residual symptoms after recompression treatment. All DCS cases, except one, occurred among the 30% of exposures that imposed the greatest decompression stress. DCS incidence among these exposures was 0.42%. PMID:12670120

  1. Effect of decompression on cystic lesions of the mandible: 3-dimensional volumetric analysis.

    PubMed

    Song, I S; Park, H S; Seo, B M; Lee, J H; Kim, M J

    2015-11-01

    Decompression is effective in reducing both the size of cystic lesions on jaws and the associated morbidity of resection. However, quantitative measurement of reduced volume after decompression among different cystic diseases has not been fully investigated. We have retrospectively investigated the difference in reduction in volume among keratocystic odontogenic tumours (n=17), unicystic ameloblastomas (n=10), and dentigerous cysts (n=10) of the posterior mandible using 3-dimensional computed tomography (CT). Various other influential factors such as age, sex, the presence of impacted teeth, and the number of drains were also recorded. There was no significant difference in the speed of shrinkage among the 3 groups, but there was a significant correlation (p<0.01) between the initial detected volume of the lesion and the absolute speed of shrinkage in each type of cyst. Initial volume was also significantly associated (p<0.01) with reduction of total volume in each type of cyst. Age may correlate negatively with the rate of reduction in dentigerous cysts, which means that the older the patient is, the less the reduction. Treatment seemed to last longer as the speed of shrinkage lessened in the keratocystic tumours and dentigerous cysts (p<0.05) as multiple regression has shown. The relative speed of shrinkage of unicystic ameloblastomas seemed to be slower when an impacted tooth was involved in the lesion (p=0.019). However, the sample size was too small to make any definite statistical statement. These results suggest that the rate of reduction of volume was related to the original size of the lesion. Despite the need for a second operation and longer duration of treatment compared with excision alone, decompression is a valuable way of reducing the size of large cystic lesions, with low morbidity and recurrence rate. There was no difference in the rate of reduction according to the underlying histopathological picture. PMID:26212420

  2. Intravascular bubble composition in guinea pigs: a possible explanation for differences in decompression risk among different gases.

    PubMed

    Lillo, R S; Maccallum, M E; Caldwell, J M

    1992-09-01

    Differences in risk of decompression sickness (DCS) that have been observed among inert gases may reflect differences in gas solubility or diffusivity or both. A higher risk gas might generate a larger volume of evolved gas during decompression, thereby increasing the probability of DCS. If this hypothesis is correct, the composition of bubbles that develop during decompression should reflect such gas differences. Unanesthetized guinea pigs were compressed to depths ranging from 250 to 350 fsw with air, He-O2 (21% O2) or one of a number of N2-He-O2 or N2-Ar-O2 mixtures (21% O2). Animals were held at depth from 15 to 60 min, then decompressed slowly (60 fsw/min) or rapidly (less than 15 s) to 5 fsw. If severe DCS developed, as judged by changes in physiologic variables, death usually occurred quickly. Gas/blood samples were then immediately withdrawn from the right atrium or the inferior vena cava, and the gas phase analyzed for He, N2, Ar, O2, and CO2 via gas chromatography. Bubbles from all dives contained 5-9% CO2, 1-4% O2, with the balance inert gas. Bubbles after N2-He-O2 dives contained substantially more N2 than He (up to 1.9 times more) compared to the dive mixture; bubbles after N2-Ar-O2 dives contained more Ar than N2 (up to 1.8 times more). For N2-He-O2 dives, the actual inert gas makeup of bubbles was dependent on the time-at-depth and the decompression profile. Results may reflect differences among He, N2, and Ar in tissue solubility/diffusivity and gas exchange rates, and support the rank order of increasing DCS risk (He less than N2 less than Ar) and rate of gas exchange (N2 less than He) observed previously during rat dives. PMID:1355314

  3. Pharmacological intervention against bubble-induced platelet aggregation in a rat model of decompression sickness

    PubMed Central

    Vallée, Nicolas; Ignatescu, Mihaela; Bourdon, Lionel

    2011-01-01

    Decompression sickness (DCS) with alterations in coagulation system and formation of platelet thrombi occurs when a subject is subjected to a reduction in environmental pressure. Blood platelet consumption after decompression is clearly linked to bubble formation in humans and offers an index for evaluating DCS severity in animal models. Previous studies highlighted a predominant involvement of platelet activation and thrombin generation in bubble-induced platelet aggregation (BIPA). To study the mechanism of the BIPA in DCS, we examined the effect of acetylsalicylic acid (ASA), heparin (Hep), and clopidogrel (Clo), with anti-thrombotic dose pretreatment in a rat model of DCS. Male Sprague-Dawley rats (n = 208) were randomly assigned to one experimental group treated before the hyperbaric exposure and decompression protocol either with ASA (3×100 mg·kg−1·day−1, n = 30), Clo (50 mg·kg−1·day−1, n = 60), Hep (500 IU/kg, n = 30), or to untreated group (n = 49). Rats were first compressed to 1,000 kPa (90 msw) for 45 min and then decompressed to surface in 38 min. In a control experiment, rats were treated with ASA (n = 13), Clo (n = 13), or Hep (n = 13) and maintained at atmospheric pressure for an equivalent period of time. Onset of DCS symptoms and death were recorded during a 60-min observation period after surfacing. DCS evaluation included pulmonary and neurological signs. Blood samples for platelet count (PC) were taken 30 min before hyperbaric exposure and 30 min after surfacing. Clo reduces the DCS mortality risk (mortality rate: 3/60 with Clo, 15/30 with ASA, 21/30 with Hep, and 35/49 in the untreated group) and DCS severity (neurological DCS incidence: 9/60 with Clo, 6/30 with ASA, 5/30 with Hep, and 12/49 in the untreated group). Clo reduced fall in platelet count and BIPA (−4,5% with Clo, −19.5% with ASA, −19,9% with Hep, and −29,6% in the untreated group). ASA, which inhibits the thromboxane A2 pathway, and Hep, which inhibits thrombin

  4. Pharmacological intervention against bubble-induced platelet aggregation in a rat model of decompression sickness.

    PubMed

    Pontier, Jean-Michel; Vallée, Nicolas; Ignatescu, Mihaela; Bourdon, Lionel

    2011-03-01

    Decompression sickness (DCS) with alterations in coagulation system and formation of platelet thrombi occurs when a subject is subjected to a reduction in environmental pressure. Blood platelet consumption after decompression is clearly linked to bubble formation in humans and offers an index for evaluating DCS severity in animal models. Previous studies highlighted a predominant involvement of platelet activation and thrombin generation in bubble-induced platelet aggregation (BIPA). To study the mechanism of the BIPA in DCS, we examined the effect of acetylsalicylic acid (ASA), heparin (Hep), and clopidogrel (Clo), with anti-thrombotic dose pretreatment in a rat model of DCS. Male Sprague-Dawley rats (n = 208) were randomly assigned to one experimental group treated before the hyperbaric exposure and decompression protocol either with ASA (3×100 mg·kg(-1)·day(-1), n = 30), Clo (50 mg·kg(-1)·day(-1), n = 60), Hep (500 IU/kg, n = 30), or to untreated group (n = 49). Rats were first compressed to 1,000 kPa (90 msw) for 45 min and then decompressed to surface in 38 min. In a control experiment, rats were treated with ASA (n = 13), Clo (n = 13), or Hep (n = 13) and maintained at atmospheric pressure for an equivalent period of time. Onset of DCS symptoms and death were recorded during a 60-min observation period after surfacing. DCS evaluation included pulmonary and neurological signs. Blood samples for platelet count (PC) were taken 30 min before hyperbaric exposure and 30 min after surfacing. Clo reduces the DCS mortality risk (mortality rate: 3/60 with Clo, 15/30 with ASA, 21/30 with Hep, and 35/49 in the untreated group) and DCS severity (neurological DCS incidence: 9/60 with Clo, 6/30 with ASA, 5/30 with Hep, and 12/49 in the untreated group). Clo reduced fall in platelet count and BIPA (-4,5% with Clo, -19.5% with ASA, -19,9% with Hep, and -29,6% in the untreated group). ASA, which inhibits the thromboxane A2 pathway, and Hep, which inhibits thrombin

  5. High-altitude decompression illness: case report and discussion

    PubMed Central

    Allan, G. Michael; Kenny, David

    2003-01-01

    DECOMPRESSION ILLNESS (DCI) CAN OCCUR in a variety of contexts, including scuba diving and flight in nonpressurized aircraft. It is characterized by joint pain, neurologic injury, and respiratory or constitutional symptoms. To prepare flight crews for accidental decompression events, the Canadian Armed Forces regularly conducts controlled and supervised depressurization exercises in specialized chambers. We present the cases of 3 Canadian Armed Forces personnel who successfully completed such decompression exercises but experienced DCI after they took a 3-hour commercial flight 6 hours after the completion of training. All 3 patients were treated in a hyperbaric oxygen chamber. The pathophysiology, diagnosis and management of DCI and the travel implications for military personnel who have undergone such training exercises are discussed. Although DCI is relatively uncommon, physicians may see it and should be aware of its presentation and treatment. PMID:14557320

  6. The Risks of Scuba Diving: A Focus on Decompression Illness

    PubMed Central

    2014-01-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or “off-gassed,” resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  7. Decompression sickness in simulated Apollo-Soyuz space missions

    NASA Technical Reports Server (NTRS)

    Cooke, J. P.; Robertson, W. G.

    1974-01-01

    Apollo-Soyuz docking module atmospheres were evaluated for incidence of decompression sickness in men simulating passage from the Russian spacecraft atmosphere, to the U.S. spacecraft atmosphere, and then to the American space suit pressure. Following 8 hr of 'shirtsleeve' exposure to 31:69::O2:N2 gas breathing mixture, at 10 psia, subjects were 'denitrogenated' for either 30 or 60 min with 100% O2 prior to decompression directly to 3.7 psia suit equivalent while performing exercise at fixed intervals. Five of 21 subjects experienced symptoms of decompression sickness after 60 min of denitrogenation compared to 6 among 20 subjects after 30 min of denitrogenation. A condition of Grade I bends was reported after 60 min of denitrogenation, and 3 of these 5 subjects noted the disappearance of all symptoms of bends at 3.7 psia. After 30 min of denitrogenation, 2 out of 6 subjects developed Grade II bends at 3.7 psia.

  8. A computerized databank of decompression sickness incidence in altitude chambers

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Bedahl, Sharon R.; Van Liew, Hugh D.

    1992-01-01

    This report describes a hypobaric decompression sickness databank (HDSD) for use with personal computers. The databank consolidates some of the decompression sickness (DCS) information that has accumulated from altitude chamber tests from 1942 to the present. The information was transcribed to a data collection form, screened for accuracy and duplication, and then added to the databank through a computer keyboard. The databank consists of two files; 63 fields contain details of the test conditions in the altitude chamber, the outcome of the test in terms of DCS and venous gas emboli, the physical characteristics of the group of subjects who underwent the test, and the denitrogenation procedures prior to decompression. The HDSD currently contains 378 records that represent 130,012 altitude exposures from 80 sources: scientific journal articles, government and contractor reports, and chapters from books.

  9. Arthroscopic Suprascapular Nerve Decompression: Transarticular and Subacromial Approach

    PubMed Central

    Bhatia, Sanjeev; Chalmers, Peter N.; Yanke, Adam B.; Romeo, Anthony A.; Verma, Nikhil N.

    2012-01-01

    Entrapment of the suprascapular nerve (SSN) is an increasingly recognized entity that can occur due to traction or compression-related etiology. Traction injuries of the SSN are unlikely to respond to surgical management and frequently improve with rest and avoidance of overhead activity. Compression injuries, on the other hand, frequently require surgical decompression for pain relief. SSN entrapment caused by compression at the suprascapular notch by the transverse scapular ligament gives rise to pain and atrophy of both the supraspinatus and infraspinatus muscles. However, compression at the spinoglenoid notch is more insidious because pain fibers may not be involved, causing isolated external rotation weakness. We present our preferred surgical technique for safe decompression of the SSN at the suprascapular and spinoglenoid notch using a subacromial and intra-articular approach, respectively. The key to ensuring efficient and uncomplicated decompression of the SSN relies on an intimate knowledge of the neurovascular anatomy and related landmarks. PMID:23766994

  10. Bubble formation in crabs induced by limb motions after decompression.

    PubMed

    McDonough, P M; Hemmingsen, E A

    1984-07-01

    In vivo bubble formation was studied in the megalopal stage of the crab Pachygrapsus crassipes. The animals were equilibrated with elevated argon, nitrogen, or helium pressures then rapidly decompressed to atmospheric pressure. Voluntary motions induced bubble nucleation in leg joints after exposures to as low as 2 atm nitrogen (gauge pressure). Delays of several minutes sometimes passed between decompression and bubble formation. Mechanically stimulating the animals to move their legs increased this bubble formation, whereas immobilizing the legs before gas equilibration prevented it, even in animals decompressed from 150 atm nitrogen. We conclude that preformed nuclei are not responsible for bubbles developing in the legs of this animal. Instead, tribonucleation of bubbles apparently occurs as a result of limb motions at relatively low gas supersaturations. PMID:6469773

  11. The risks of scuba diving: a focus on Decompression Illness.

    PubMed

    Hall, Jennifer

    2014-11-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or "off-gassed," resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  12. A critical review of physiological bubble formation in hyperbaric decompression.

    PubMed

    Papadopoulou, Virginie; Eckersley, Robert J; Balestra, Costantino; Karapantsios, Thodoris D; Tang, Meng-Xing

    2013-05-01

    Bubbles are known to form in the body after scuba dives, even those done well within the decompression model limits. These can sometimes trigger decompression sickness and the dive protocols should therefore aim to limit bubble formation and growth from hyperbaric decompression. Understanding these processes physiologically has been a challenge for decades and there are a number of questions still unanswered. The physics and historical background of this field of study is presented and the latest studies and current developments reviewed. Heterogeneous nucleation is shown to remain the prime candidate for bubble formation in this context. The two main theories to account for micronuclei stability are then to consider hydrophobicity of surfaces or tissue elasticity, both of which could also explain some physiological observations. Finally the modeling relevance of the bubble formation process is discussed, together with that of bubble growth as well as multiple bubble behavior. PMID:23523006

  13. Spinal Epidural Hematoma after Thoracolumbar Posterior Fusion Surgery without Decompression for Thoracic Vertebral Fracture

    PubMed Central

    Minato, Tsuyoki; Miyagi, Masayuki; Saito, Wataru; Shoji, Shintaro; Nakazawa, Toshiyuki; Inoue, Gen; Imura, Takayuki; Minehara, Hiroaki; Matsuura, Terumasa; Kawamura, Tadashi; Namba, Takanori; Takahira, Naonobu; Takaso, Masashi

    2016-01-01

    We present a rare case of spinal epidural hematoma (SEH) after thoracolumbar posterior fusion without decompression surgery for a thoracic vertebral fracture. A 42-year-old man was hospitalized for a thoracic vertebral fracture caused by being sandwiched against his back on broken concrete block. Computed tomography revealed a T12 dislocation fracture of AO type B2, multiple bilateral rib fractures, and a right hemopneumothorax. Four days after the injury, in order to promote early orthostasis and to improve respiratory status, we performed thoracolumbar posterior fusion surgery without decompression; the patient had back pain but no neurological deficits. Three hours after surgery, he complained of acute pain and severe weakness of his bilateral lower extremities; with allodynia below the level of his umbilicus, postoperative SEH was diagnosed. We performed immediate revision surgery. After removal of the hematoma, his symptoms improved gradually, and he was discharged ambulatory one month after revision surgery. Through experience of this case, we should strongly consider the possibility of preexisting SEH before surgery, even in patients with no neurological deficits. We should also consider perioperative coagulopathy in patients with multiple trauma, as in this case. PMID:26989542

  14. Microvascular decompression of the posterior inferior cerebellar artery for intermediate nerve neuralgia

    PubMed Central

    Schroeder, Humberto Kluge; Neville, Iuri Santana; de Andrade, Daniel Ciampi; Lepski, Guilherme Alves; Teixeira, Manoel Jacobsen; Duarte, Kleber Paiva

    2015-01-01

    Background: Intermediate nerve neuralgia (INN) is an extremely rare craniofacial pain disorder mainly caused by neurovascular compression. Case Description: We present the case of a 48-year-old female with a 20-month history of intractable paroxysmal INN on the right side. The patient described feeling paroxysmal pain in her auditory canal, pinna, deep in the jaw, and adjacent retromastoid area on the right side. She described the pain as being like a burning sensation. Magnetic resonance imaging showed the right posterior cerebellar artery crossing the cerebellopontine cistern in close contact with the right VII and VIII nerves. Surgical exploration via retromastoid craniotomy revealed vascular compression of the intermediate nerve by the posterior cerebellar artery. We therefore performed microvascular nerve decompression to relieve pain, and the patient remained pain-free at the 6-month follow-up visit. Conclusion: INN should be considered as a differential diagnosis in cases with atypical facial neuralgia, and microvascular decompression is an effective treatment option that can provide optimal pain relief. PMID:25883844

  15. The extreme solar cosmic ray particle event on 20 January 2005 and its influence on the radiation dose rate at aircraft altitude.

    PubMed

    Bütikofer, R; Flückiger, E O; Desorgher, L; Moser, M R

    2008-03-01

    In January 2005 toward the end of solar activity cycle 23 the Sun was very active. Between 15 and 20 January 2005, the solar active region NOAA AR 10720 produced five powerful solar flares. In association with this major solar activity several pronounced variations in the ground-level cosmic ray intensity were observed. The fifth of these flares (X7.1) produced energetic solar cosmic rays that caused a giant increase in the count rates of the ground-based cosmic ray detectors (neutron monitors). At southern polar neutron monitor stations the increase of the count rate reached several thousand percent. From the recordings of the worldwide network of neutron monitors, we determined the characteristics of the solar particle flux near Earth. In the initial phase of the event, the solar cosmic ray flux near Earth was extremely anisotropic. The energy spectrum of the solar cosmic rays was fairly soft during the main and the decay phase. We investigated also the flux of different secondary particle species in the atmosphere and the radiation dosage at flight altitude. Our analysis shows a maximum increment of the effective dose rate due to solar cosmic rays in the south polar region around 70 degrees S and 130 degrees E at flight altitude of almost three orders of magnitude. PMID:18031791

  16. Expansion of bubbles under a pulsatile flow regime in decompressed ovine blood vessels.

    PubMed

    Arieli, Ran; Marmur, Abraham

    2016-02-01

    After decompression of ovine large blood vessels, bubbles nucleate and expand at active hydrophobic spots on their luminal aspect. These bubbles will be in the path of the blood flow within the vessel, which might replenish the supply of gas-supersaturated plasma in their vicinity and thus, in contrast with our previous estimations, enhance their growth. We used the data from our previous study on the effect of pulsatile flow in ovine blood vessels stretched on microscope slides and photographed after decompression from hyperbaric exposure. We measured the diameter of 46 bubbles in 4 samples taken from 3 blood vessels (pulmonary artery, pulmonary vein, and aorta) in which both a "multi-bubble active spot" (MBAS)--which produces several bubbles at a time, and at least one "single-bubble active spot" (SBAS)--which produces a single bubble at a time, were seen together. The linear expansion rate for diameter in SBAS ranged from 0.077 to 0.498 mm/min and in MBAS from 0.001 to 0.332 mm/min. There was a trend toward a reduced expansion rate for bubbles in MBAS compared with SBAS. The expansion rate for bubbles in an MBAS when it was surrounded by others was very low. Bubble growth is related to gas tension, and under a flow regime, bubbles expand from a diameter of 0.1 to 1mm in 2-24 min at a gas supersaturation of 620 kPa and lower. There are two phases of bubble development. The slow and disperse initiation of active spots (from nanobubbles to gas micronuclei) continues for more than 1h, whereas the fast increase in size (2-24 min) is governed by diffusion. Bubble-based decompression models should not artificially reduce diffusion constants, but rather take both phases of bubble development into consideration. PMID:26592146

  17. Decompression to altitude: assumptions, experimental evidence, and future directions.

    PubMed

    Foster, Philip P; Butler, Bruce D

    2009-02-01

    Although differences exist, hypobaric and hyperbaric exposures share common physiological, biochemical, and clinical features, and their comparison may provide further insight into the mechanisms of decompression stress. Although altitude decompression illness (DCI) has been experienced by high-altitude Air Force pilots and is common in ground-based experiments simulating decompression profiles of extravehicular activities (EVAs) or astronauts' space walks, no case has been reported during actual EVAs in the non-weight-bearing microgravity environment of orbital space missions. We are uncertain whether gravity influences decompression outcomes via nitrogen tissue washout or via alterations related to skeletal muscle activity. However, robust experimental evidence demonstrated the role of skeletal muscle exercise, activities, and/or movement in bubble formation and DCI occurrence. Dualism of effects of exercise, positive or negative, on bubble formation and DCI is a striking feature in hypobaric exposure. Therefore, the discussion and the structure of this review are centered on those highlighted unresolved topics about the relationship between muscle activity, decompression, and microgravity. This article also provides, in the context of altitude decompression, an overview of the role of denitrogenation, metabolic gases, gas micronuclei, stabilization of bubbles, biochemical pathways activated by bubbles, nitric oxide, oxygen, anthropometric or physiological variables, Doppler-detectable bubbles, and potential arterialization of bubbles. These findings and uncertainties will produce further physiological challenges to solve in order to line up for the programmed human return to the Moon, the preparation for human exploration of Mars, and the EVAs implementation in a non-zero gravity environment. PMID:19074573

  18. The 1990 Hypobaric Decompression Sickness Workshop: Summary and conclusions

    NASA Technical Reports Server (NTRS)

    Pilmanis, Andrew A.; Stegmann, Barbara J.; Scoggins, Terrell E.

    1992-01-01

    Decompression sickness resulting from exposure to the hypobaric environment was reviewed and discussed at a three day workshop in Oct. 1990. This milestone meeting, attended by over 50 participants representing the Dept. of Defense, NASA, ESA, and academia, updated the current understanding of altitude decompression sickness (DCS). Both research and operational aspects of this illness were addressed through presentations on the pathophysiology and clinical manifestations of DCS, its incidence in aviation and space operations, and existing and proposed measures for DCS prevention. Specific areas requiring further research were also identified. A summary is presented for the material given at the workshop.

  19. A randomised controlled trial of post-operative rehabilitation after surgical decompression of the lumbar spine

    PubMed Central

    Denzler, Raymond; Dvorak, Jiri; Müntener, Markus; Grob, Dieter

    2007-01-01

    Spinal decompression is the most common type of spinal surgery carried out in the older patient, and is being performed with increasing frequency. Physiotherapy (rehabilitation) is often prescribed after surgery, although its benefits compared with no formal rehabilitation have yet to be demonstrated in randomised control trials. The aim of this randomised controlled trial was to examine the effects on outcome up to 2 years after spinal decompression surgery of two types of postoperative physiotherapy compared with no postoperative therapy (self-management). Hundred and fifty-nine patients (100 men, 59 women; 65 ± 11 years) undergoing decompression surgery for spinal stenosis/herniated disc were randomised to one of the following programmes beginning 2 months post-op: recommended to “keep active” (CONTROL; n = 54); physiotherapy, spine stabilisation exercises (PT-StabEx; n = 56); physiotherapy, mixed techniques (PT-Mixed; n = 49). Both PT programmes involved 2 × 30 min sessions/week for up to 12 weeks, with home exercises. Pain intensity (0–10 graphic rating scale, for back and leg pain separately) and self-rated disability (Roland Morris) were assessed before surgery, before and after the rehabilitation phase (approx. 2 and 5 months post-op), and at 12 and 24 months after the operation. ‘Intention to treat’ analyses were used. At 24 months, 151 patients returned questionnaires (effective return rate, excluding 4 deaths, 97%). Significant reductions in leg and back pain and self-rated disability were recorded after surgery (P < 0.05). Pain showed no further changes in any group up to 24 months later, whereas disability declined further during the “rehabilitation” phase (P < 0.05) then stabilised, but with no significant group differences. 12 weeks of post-operative physiotherapy did not influence the course of change in pain or disability up to 24 months after decompression surgery. Advising patients to keep active by

  20. The effectiveness of percutaneous laser disc decompression for the prolapsed lumbar intervertebral disc

    NASA Astrophysics Data System (ADS)

    Mu, Ming Wei; Liu, Wei; Feng, Wei; Ma, Nan

    2009-07-01

    Objective: to investigate the role of associated factors in the effectiveness of laser treatment for prolapsed lumber intervertebral disc. Method: 302 prolapsed lumber intervertebral discs in 212 patients were treated with percutaneous laser disc decompression (PLDD). Patients were followed up by 12month, the associated factors which affecting the effectiveness of treatment, ie age, duration of illness were analyzed. Results: Punctual Success rate was 100%. After 12 month's follow up, 86% successful outcomes were obtained, in which 93% successful outcomes were obtained in patients less than 50 years old, 92% successful outcomes was obtained in the patients whose duration of illness less than 1 year.

  1. Clinical outcomes after decompressive laminectomy for symptomatic ossification of ligamentum flavum at the thoracic spine.

    PubMed

    Zhong, Zhao-Ming; Wu, Qian; Meng, Ting-Ting; Zhu, Yong-Jian; Qu, Dong-Bin; Wang, Ji-Xing; Jiang, Jian-Ming; Lu, Kai-Wu; Zheng, Shuai; Zhu, Si-Yuan; Chen, Jian-Ting

    2016-06-01

    Ossification of the ligamentum flavum (OLF) is a rare disease that causes acquired thoracic spinal canal stenosis and thoracic myelopathy. The aim of this study was to investigate clinical outcomes of symptomatic thoracic OLF treated using posterior decompressive laminectomy. We retrospectively analyzed the medical records of 22 patients who underwent posterior decompressive laminectomy for symptomatic thoracic OLF. The surgical results were evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system and Hirabayashi recovery rate. The intensity of pain was evaluated using a visual analog scale (VAS). The mean duration of follow-up was 35.6months. The mean JOA score was significantly improved at final follow-up (9.18±standard deviation of 1.53 points [range, 6-11 points]) compared with before surgery (5.64±2.04 points [range, 3-9 points]) (P<0.001). The mean Hirabayashi recovery rate was 65.49% (range, 20-100%). Recovery outcomes were excellent in nine patients, good in eight patients, fair in four patients and unchanged in one patient. No patient was classified as deteriorated. The VAS scores were 2.82±3.08 before surgery and 0.59±1.05 at final follow-up (P=0.001). Surgical complications, which resolved after appropriate and prompt treatment, included dural tear in five patients, cerebrospinal fluid leakage in one patient, immediate postoperative neurologic deterioration in one patient, epidural hematoma in one patient, and wound infection in one patient. Our findings suggest that posterior decompressive laminectomy is an effective treatment for symptomatic thoracic OLF and provides satisfactory clinical improvement, but surgery for thoracic OLF is associated with a relatively high incidence of complications. PMID:26898582

  2. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives...

  3. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives...

  4. Hyperbaric oxygen pre-breathe modifies the outcome of decompression sickness.

    PubMed

    Butler, B D; Little, T; Cogan, V; Powell, M

    2006-01-01

    Deep sea divers, aviators and astronauts are at risk of decompression sickness when the ambient pressure reductions exceed a critical threshold. Venous bubbles associated with decompression sickness have the potential to react with the vascular membrane and adjacent blood products, eliciting an inflammatory cascade. Preventive measures usually involve careful decompression procedures to avoid or reduce bubble formation. De-nitrogenation with 100% oxygen pre-breathing as a preventive measure has been well established at least in altitude decompression exposures. The objective of this study was to determine the physiological and biochemical effects of Hyperbaric Oxygen Pre-breathe (HBOP) upon decompression from a hyperbaric exposure. Male Sprague-Dawley rats were randomly assigned to one of eight groups. Two experimental groups received HBOP at 1 and 18 hours prior to decompression, as compared with ground level oxygen or non-treated groups that still experienced decompression stress, and the associated non-decompressed controls. The results showed decreased extravascular lung water (pulmonary edema), bronchoalveolar lavage and pleural protein and arterial, broncho-alveolar lavage, and urine leukotriene E4 (LKE4) levels in both the 1Hr and 18Hr HBOP decompressed rats compared to non-oxygenated decompressed rats, as well as a decreased overall expression of signs of decompression sickness. This study indicates that HBOP-treated rats exhibit fewer signs and complications of decompression sickness compared with non-treated or ground level oxygen treated rats. PMID:17274310

  5. Synthesis and extreme rate capability of Si-Al-C-N functionalized carbon nanotube spray-on coatings as Li-ion battery electrode.

    PubMed

    David, Lamuel; Asok, Deepu; Singh, Gurpreet

    2014-09-24

    Silicon-based precursor derived glass-ceramics or PDCs have proven to be an attractive alternative anode material for Li ion batteries. Main challenges associated with PDC anodes are their low electrical conductivity, first cycle loss, and meager C-rate performance. Here, we show that thermal conversion of single source aluminum-modified polysilazane on the surfaces of carbon nanotubes (CNTs) results in a robust Si-Al-C-N/CNT shell/core composite that offers extreme C-rate capability as battery electrode. Addition of Al to the molecular network of Si-C-N improved electrical conductivity of Si-C-N by 4 orders of magnitude, while interfacing with CNTs showed 7-fold enhancement. Further, we present a convenient spray-coating technique for PDC composite electrode preparation that eliminates polymeric binder and conductive agent there-by reducing processing steps and eradicating foreign material in the electrode. The Si-Al-C-N/CNT electrode showed stable charge capacity of 577 mAh g(-1) at 100 mA g(-1) and a remarkable 400 mAh g(-1) at 10,000 mA g(-1), which is the highest reported value for a silazane derived glass-ceramic or nanocomposite electrode. Under symmetric cycling conditions, a high charge capacity of ∼350 mA g(-1) at 1600 mA g(-1) was continuously observed for over 1000 cycles. PMID:25178109

  6. Limited Unilateral Decompression and Pedicle Screw Fixation with Fusion for Lumbar Spinal Stenosis with Unilateral Radiculopathy: A Retrospective Analysis of 25 Cases

    PubMed Central

    Zhang, Li; Miao, Hai-xiong; Wang, Yong; Chen, An-fu; Zhang, Tao

    2015-01-01

    Objective Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images. Results Twenty-five patients were included. The mean preoperative VAS score was 6.6±1.6 and 4.6±3.1 for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, 1.32±1.2) and the back (VAS score, 1.75±1.73) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively (6.60±6.5; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01). Conclusion Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine. PMID:26279816

  7. A Log Logistic Survival Model Applied to Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny

    2001-01-01

    Decompression sickness (DCS) is a complex, multivariable problem. A mathematical description or model of the likelihood of DCS requires a large amount of quality research data, ideas on how to define a decompression dose using physical and physiological variables, and an appropriate analytical approach. It also requires a high-performance computer with specialized software. I have used published DCS data to develop my decompression doses, which are variants of equilibrium expressions for evolved gas plus other explanatory variables. My analytical approach is survival analysis, where the time of DCS occurrence is modeled. My conclusions can be applied to simple hypobaric decompressions - ascents lasting from 5 to 30 minutes - and, after minutes to hours, to denitrogenation (prebreathing). They are also applicable to long or short exposures, and can be used whether the sufferer of DCS is at rest or exercising at altitude. Ultimately I would like my models to be applied to astronauts to reduce the risk of DCS during spacewalks, as well as to future spaceflight crews on the Moon and Mars.

  8. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.332 PVHO—Decompression chambers... minimum pressure capability of— (1) 6 ATA, when used for diving to 300 fsw; or (2) The maximum depth of the dive, when used for diving operations deeper than 300 fsw, unless a closed bell meeting...

  9. Does temperature increase or decrease in adiabatic decompression of magma?

    NASA Astrophysics Data System (ADS)

    Kilinc, A. I.; Ghiorso, M. S.; Khan, T.

    2011-12-01

    We have modeled adiabatic decompression of an andesitic and a basaltic magma as an isentropic process using the Melts algorithm. Our modeling shows that during adiabatic decompression temperature of andesitic magma increases but temperature of basaltic magma decreases. In an isentropic process entropy is constant so change of temperature with pressure can be written as dT/dP=T (dV/dT)/Cp where T (dV/dT)/Cp is generally positive. If delta P is negative so is delta T. In general, in the absence of phase change, we expect the temperature to decrease with adiabatic decompression. The effect of crystallization is to turn a more entropic phase (liquid) into a less entropic phase (solid), which must be compensated by raising the temperature. If during adiabatic decompression there is small amount or no crystallization, T (dV/dT)/Cp effect which lowers the temperature overwhelms the small amount of crystallization, which raises the temperature, and overall system temperature decreases.

  10. Pediatric traumatic brain injuries treated with decompressive craniectomy

    PubMed Central

    Patel, Neil; West, Michael; Wurster, Joanie; Tillman, Cassie

    2013-01-01

    Background: Traumatic brain injury (TBI) occurs in an estimated 80% of all pediatric trauma patients and is the leading cause of death and disability in the pediatric population. Decompressive craniectomy is a procedure used to decrease intracranial pressure by allowing the brain room to swell and therefore increase cerebral perfusion to the brain. Methods: This is a retrospective study done at St. Mary's Medical Center/Palm Beach Children's Hospital encompassing a 3 year 7 month period. All the pediatric patients who sustained a TBI and who were treated with a decompressive craniectomy were included. The patients’ outcomes were monitored and scored according to the Rancho Los Amigos Score at the time of discharge from the hospital and 6 months postdischarge. Results: A total of 379 pediatric patients with a diagnosis of TBI were admitted during this time. All these patients were treated according to the severity of their injury. A total of 49 pediatric patients required neurosurgical intervention and 7 of these patients met the criteria for a decompressive craniectomy. All seven patients returned home with favorable outcomes. Conclusion: This study supports the current literature that decompressive craniectomy is no longer an intervention used as a last resort but an effective first line treatment to be considered. PMID:24232244

  11. Ventral Decompression in Chiari Malformation, Basilar Invagination, and Related Disorders.

    PubMed

    Ridder, Thomas; Anderson, Richard C E; Hankinson, Todd C

    2015-10-01

    Ventral brainstem compression is an uncommon clinical diagnosis seen by pediatric neurosurgeons and associated with Chiari malformation, type I. Presenting clinical symptoms often include headaches, lower cranial neuropathies, myelopathy, central sleep apnea, ataxia, and nystagmus. When ventral decompression is required, both open and endoscopic transoral/transnasal approaches are highly effective. PMID:26408067

  12. Decompressive Craniectomy and Traumatic Brain Injury: A Review

    PubMed Central

    Alvis-Miranda, Hernando; Castellar-Leones, Sandra Milena; Moscote-Salazar, Luis Rafael

    2013-01-01

    Intracranial hypertension is the largest cause of death in young patients with severe traumatic brain injury. Decompressive craniectomy is part of the second level measures for the management of increased intracranial pressure refractory to medical management as moderate hypothermia and barbiturate coma. The literature lack of concepts is their indications. We present a review on the state of the art. PMID:27162826

  13. Percutaneous laser disc decompression with the holmium: YAG laser.

    PubMed

    Casper, G D; Hartman, V L; Mullins, L L

    1995-06-01

    This article discusses the evolution of the percutaneous laser disc decompression (PLDD) method using a holmium:YAG laser. Advantages of using this wavelength and several techniques for its use in PLDD are reviewed. The article also discusses the current devices and delivery systems available for this application. PMID:10150646

  14. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Decompression Tables A Appendix A to Subpart S of Part 1926 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Underground Construction, Caissons, Cofferdams and Compressed Air Pt....

  15. Application of real-time B-mode ultrasound in posterior decompression and reduction for thoracolumbar burst fracture.

    PubMed

    Yang, Wu-Peng; Wang, Zhe; Feng, Nai-Qi; Wang, Chun-Mei; DU, Shao-Long

    2013-10-01

    This study aimed to investigate the role of real-time B-mode ultrasound in posterior decompression and reduction and to observe the signal changes in spinal cord blood flow in a thoracolumbar burst fracture (TBF). Between February 2004 and December 2008, 138 patients with TBF were divided into group A (108 cases) and group B (30 cases). In group A, under the assistance of real-time B-mode ultrasound, posterior decompression and fracture piece reduction were performed, and we observed the signal changes in spinal cord blood flow. In group B, posterior fenestration was combined with pushing the fracture piece into the fractured vertebral body using an L-shaped operative tool. Presurgical and postsurgical recovery of neurological function was evaluated according to American Spinal Injury Association (ASIA) standards, and the range of spinal decompression was determined by measuring the proportion of encroached fracture piece in the spinal canal (spinal stenosis rate) on the computed tomography (CT) image. In group A, 12 patients had a grade A spinal injury according to the Frankel grading system, and there were six cases without neurological recovery. In the other patients, neurological function increased by 1-3 grades. There were no aggravated spinal cord injuries or other serious complications. In group B, three patients were categorized as grade A and there were two cases without neurological recovery. In the other patients, neurological function increased by 1-3 grades. In groups A and B, the postsurgical spinal stenosis rate was significantly lower than the presurgical stenosis rate (P<0.05). The postsurgical spinal stenosis rate in group B was significantly higher compared with group A (P<0.05). There was no significant difference in neurological function recovery between the groups (P>0.05). Real-time B-mode ultrasound is an effective method for posterior decompression and reduction and to observe signal changes in spinal cord blood flow in TBF. PMID:24137306

  16. Laminoplasty and Laminectomy Hybrid Decompression for the Treatment of Cervical Spondylotic Myelopathy with Hypertrophic Ligamentum Flavum: A Retrospective Study

    PubMed Central

    Ding, Huairong; Xue, Yuan; Tang, Yanming; He, Dong; Li, Zhiyang; Zhao, Ying; Zong, Yaqi; Wang, Yi; Wang, Pei

    2014-01-01

    Objective To report the outcomes of a posterior hybrid decompression protocol for the treatment of cervical spondylotic myelopathy (CSM) associated with hypertrophic ligamentum flavum (HLF). Background Laminoplasty is widely used in patients with CSM; however, for CSM patients with HLF, traditional laminoplasty does not include resection of a pathological ligamentum flavum. Methods This study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale. Results No hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3±15.5%. Mean cervical lordotic angle had decreased 4.9 degrees by 1 year after surgery (P<0.05). Preservation of cervical range of motion was satisfactory postoperatively. Bone healing rates 6 months after surgery were 100% on the hinge side and 92.2% on the open side. Satisfactory decompression was demonstrated by a significantly increased sagittal canal diameter and cross-sectional area of the dural sac together with a significant drift-back distance of the spinal cord. The dural sac was also adequately expanded at the time of the final follow-up visit. Conclusion Hybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF. PMID:24740151

  17. Application of real-time B-mode ultrasound in posterior decompression and reduction for thoracolumbar burst fracture

    PubMed Central

    YANG, WU-PENG; WANG, ZHE; FENG, NAI-QI; WANG, CHUN-MEI; DU, SHAO-LONG

    2013-01-01

    This study aimed to investigate the role of real-time B-mode ultrasound in posterior decompression and reduction and to observe the signal changes in spinal cord blood flow in a thoracolumbar burst fracture (TBF). Between February 2004 and December 2008, 138 patients with TBF were divided into group A (108 cases) and group B (30 cases). In group A, under the assistance of real-time B-mode ultrasound, posterior decompression and fracture piece reduction were performed, and we observed the signal changes in spinal cord blood flow. In group B, posterior fenestration was combined with pushing the fracture piece into the fractured vertebral body using an L-shaped operative tool. Presurgical and postsurgical recovery of neurological function was evaluated according to American Spinal Injury Association (ASIA) standards, and the range of spinal decompression was determined by measuring the proportion of encroached fracture piece in the spinal canal (spinal stenosis rate) on the computed tomography (CT) image. In group A, 12 patients had a grade A spinal injury according to the Frankel grading system, and there were six cases without neurological recovery. In the other patients, neurological function increased by 1–3 grades. There were no aggravated spinal cord injuries or other serious complications. In group B, three patients were categorized as grade A and there were two cases without neurological recovery. In the other patients, neurological function increased by 1–3 grades. In groups A and B, the postsurgical spinal stenosis rate was significantly lower than the presurgical stenosis rate (P<0.05). The postsurgical spinal stenosis rate in group B was significantly higher compared with group A (P<0.05). There was no significant difference in neurological function recovery between the groups (P>0.05). Real-time B-mode ultrasound is an effective method for posterior decompression and reduction and to observe signal changes in spinal cord blood flow in TBF. PMID

  18. Role of Inflammatory Reponse in Experimental Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Little, T.

    1999-01-01

    Decompression to altitude can result in gas bubble formation both in tissues and in the systemic veins. The venous gas emboli (VGE) are often monitored during decompression exposures to assess risk for decompression sickness (DCS). Astronauts are at risk for DCS during extravehicular activities (EVA), where decompression occurs from the Space Shuttle or Space Station atmospheric pressure of 14.7 pounds per square inch (PSI) to that of the space suit pressure of 4.3 PSI. DCS symptoms include diffuse pain, especially around joints, inflammation and edema. Pathophysiological effects include interstitial inflammatory responses and recurring injury to the vascular endothelium. Such responses can result in vasoconstriction and associated hemodynamic changes.The granulocyte cell activation and chemotaxin release results in the formation of vasoactive and microvascular permeability altering mediators, especially from the lungs which are the principal target organ for the venous bubbles, and from activated cells (neutrophils, platelets, macrophages). Such mediators include free arachidonic acid and the byproducts of its metabolism via the cyclooxygenase and lipoxygenase pathways (see figure). The cyclooxygenase pathway results in formation of prostacyclin and other prostaglandins and thromboxanes that cause vasoconstriction, bronchoconstriction and platelet aggregation. Leukotrienes produced by the alternate pathway cause pulmonary and bronchial smooth muscle contraction and edema. Substances directly affecting vascular tone such as nitric oxide may also play a role in the respose to DCS. We are studying the role and consequent effects of the release inflammatory bioactive mediators as a result of DCS and VGE. More recent efforts are focused on identifying the effects of the body's circadian rhythm on these physiological consequences to decompression stress. al

  19. Application of bioabsorbable screw fixation for anterior cervical decompression and bone grafting

    PubMed Central

    Zhao, Bo; Qiu, Xiaowen; Wang, Dong; Li, Haopeng; He, Xijing

    2016-01-01

    OBJECTIVES: To examine the application of bioabsorbable screws for anterior cervical decompression and bone grafting fixation and to study their clinical effects in the treatment of cervical spondylosis. METHODS: From March 2007 to September 2012, 56 patients, 36 males and 20 females (38-79 years old, average 58.3±9.47 years), underwent a novel operation. Grafts were fixed by bioabsorbable screws (PLLA, 2.7 mm in diameter) after anterior decompression. The bioabsorbable screws were inserted from the midline of the graft bone to the bone surface of the upper and lower vertebrae at 45 degree angles. Patients were evaluated post-operatively to observe the improvement of symptoms and evaluate the fusion of the bone. The Japanese Orthopaedic Association (JOA) score was used to evaluate the recovery of neurological functions. RESULTS: All screws were successfully inserted, with no broken screws. The rate of symptom improvement was 87.5%. All of the grafts fused well with no extrusion. The average time for graft fusion was 3.8±0.55 months (range 3-5 months). Three-dimensional reconstruction of CT scans demonstrated that the grafts fused with adjacent vertebrae well and that the screws were absorbed as predicted. The MRI findings showed that the cerebrospinal fluid was unobstructed. No obvious complications appeared in any of the follow-up evaluations. CONCLUSIONS: Cervical spondylosis with one- or two-level involvement can be effectively treated by anterior decompression and bone grafting with bioabsorbable screw fixation. This operative method is safe and can avoid the complications induced by metal implants. PMID:27438565

  20. Long-Term Incidence and Predicting Factors of Cranioplasty Infection after Decompressive Craniectomy

    PubMed Central

    Im, Sang-Hyuk; Han, Young-Min; Kim, Jong-Tae; Chung, Dong Sup; Park, Young Sup

    2012-01-01

    Objective The predictors of cranioplasty infection after decompressive craniectomy have not yet been fully characterized. The objective of the current study was to compare the long-term incidences of surgical site infection according to the graft material and cranioplasty timing after craniectomy, and to determine the associated factors of cranioplasty infection. Methods A retrospective cohort study was conducted to assess graft infection in patients who underwent cranioplasty after decompressive craniectomy between 2001 and 2011 at a single-center. From a total of 197 eligible patients, 131 patients undergoing 134 cranioplasties were assessed for event-free survival according to graft material and cranioplasty timing after craniectomy. Kaplan-Meier survival analysis and Cox regression methods were employed, with cranioplasty infection identified as the primary outcome. Secondary outcomes were also evaluated, including autogenous bone resorption, epidural hematoma, subdural hematoma and brain contusion. Results The median follow-up duration was 454 days (range 10 to 3900 days), during which 14 (10.7%) patients suffered cranioplasty infection. There was no significant difference between the two groups for event-free survival rate for cranioplasty infection with either a cryopreserved or artificial bone graft (p=0.074). Intergroup differences according to cranioplasty time after craniectomy were also not observed (p=0.083). Poor neurologic outcome at cranioplasty significantly affected the development of cranioplasty infection (hazard ratio 5.203, 95% CI 1.075 to 25.193, p=0.04). Conclusion Neurologic status may influence cranioplasty infection after decompressive craniectomy. A further prospective study about predictors of cranioplasty infection including graft material and cranioplasty timing is necessary. PMID:23133731

  1. A minimally invasive technique for decompression of Chiari malformation type I (DECMI study): study protocol for a randomised controlled trial

    PubMed Central

    Hu, Yu; Liu, Jiagang; Chen, Haifeng; Jiang, Shu; Li, Qiang; Fang, Yuan; Gong, Shuhui; Wang, Yuelong; Huang, Siqing

    2015-01-01

    Introduction Chiari malformation type I (CM-I) is a congenital hindbrain anomaly that requires surgical decompression in symptomatic patients. Posterior fossa decompression with duraplasty (PFDD) has been widely practiced in Chiari decompression, but dural opening carries a high risk of surgical complications. A minimally invasive technique, dural splitting decompression (DSD), preserves the inner layer of the dura without dural opening and duraplasty, potentially reducing surgical complications, length of operative time and hospital stay, and cost. If DSD is non-inferior to PFDD in terms of clinical improvement, DSD could be an alternative treatment modality for CM-I. So far, no randomised study of surgical treatment of CM-I has been reported. This study aims to evaluate if DSD is an effective, safe and cost-saving treatment modality for adult CM-I patients, and may provide evidence for using the minimally invasive procedure extensively. Methods and analysis DECMI is a randomised controlled, single-masked, non-inferiority, single centre clinical trial. Participants meeting the criteria will be randomised to the DSD group and the PFDD group in a 1:1 ratio. The primary outcome is the rate of clinical improvement, which is defined as the complete resolution or partial improvement of the presenting symptoms/signs. The secondary outcomes consist of the incidence of syrinx reduction, postoperative morbidity rates, reoperation rate, quality of life (QoL) and healthcare resource utilisation. A total of 160 patients will be included and followed up at 3 and 12 months postoperatively. Ethics and dissemination The study protocol was approved by the Biological and Medical Ethics Committee of West China Hospital. The findings of this trial will be published in a peer-reviewed scientific journal and presented at scientific conferences. Trial registration number ChiCTR-TRC-14004099. PMID:25926152

  2. Multifactorial inheritance, rates of maturation and psychiatry's taxonomic dilemma: on Saugstad's "radical proposition" for two extremes of brain function and structure.

    PubMed

    deVries, Marten W

    2008-06-01

    This paper reviews aspects of Letten F. Saugstad's Maturation Theory in relation to the Kraepelinian dichotomy and psychiatric classification. The maturation theory is based on existing neuroscience, cross-national and mental health case register data and offers an innovative alternative to current etiological formulations. The maturational theory holds (1) that manic depressive illness relates to early maturation and (2) the schizophrenic syndrome relates to late maturation. The foundation of these processes lies in cerebral pruning of excitatory synapses particularly at puberty but also at a number of earlier crucial periods in development. The process of synaptic pruning has by puberty eliminated some 40% of the synapses, leading to the disappearance of glutematergic excitatory synapses without apparently appreciably influencing inhibitory GABAergic neurons. As a consequence, early maturation is related to the manic-depressive syndrome and characterized by increased neural excitability. Conversely, late maturation is related to schizophrenia characterized by diminished neural activity. Saugstad demonstrates using cross-national and neuroscience studies the multifactoral and environmental influences on rates of maturation and thereby mental illness. Using these data Saugstad reasons her agreement with the Kraepelinian dichotomy based on the existence of two extremes in brain structure and function developed through interactions between the person and the environment. PMID:18516513

  3. Valuation of Indonesian catastrophic earthquake bonds with generalized extreme value (GEV) distribution and Cox-Ingersoll-Ross (CIR) interest rate model

    NASA Astrophysics Data System (ADS)

    Gunardi, Setiawan, Ezra Putranda

    2015-12-01

    Indonesia is a country with high risk of earthquake, because of its position in the border of earth's tectonic plate. An earthquake could raise very high amount of damage, loss, and other economic impacts. So, Indonesia needs a mechanism for transferring the risk of earthquake from the government or the (reinsurance) company, as it could collect enough money for implementing the rehabilitation and reconstruction program. One of the mechanisms is by issuing catastrophe bond, `act-of-God bond', or simply CAT bond. A catastrophe bond issued by a special-purpose-vehicle (SPV) company, and then sold to the investor. The revenue from this transaction is joined with the money (premium) from the sponsor company and then invested in other product. If a catastrophe happened before the time-of-maturity, cash flow from the SPV to the investor will discounted or stopped, and the cash flow is paid to the sponsor company to compensate their loss because of this catastrophe event. When we consider the earthquake only, the amount of discounted cash flow could determine based on the earthquake's magnitude. A case study with Indonesian earthquake magnitude data show that the probability of maximum magnitude can model by generalized extreme value (GEV) distribution. In pricing this catastrophe bond, we assumed stochastic interest rate that following the Cox-Ingersoll-Ross (CIR) interest rate model. We develop formulas for pricing three types of catastrophe bond, namely zero coupon bonds, `coupon only at risk' bond, and `principal and coupon at risk' bond. Relationship between price of the catastrophe bond and CIR model's parameter, GEV's parameter, percentage of coupon, and discounted cash flow rule then explained via Monte Carlo simulation.

  4. Valuation of Indonesian catastrophic earthquake bonds with generalized extreme value (GEV) distribution and Cox-Ingersoll-Ross (CIR) interest rate model

    SciTech Connect

    Gunardi,; Setiawan, Ezra Putranda

    2015-12-22

    Indonesia is a country with high risk of earthquake, because of its position in the border of earth’s tectonic plate. An earthquake could raise very high amount of damage, loss, and other economic impacts. So, Indonesia needs a mechanism for transferring the risk of earthquake from the government or the (reinsurance) company, as it could collect enough money for implementing the rehabilitation and reconstruction program. One of the mechanisms is by issuing catastrophe bond, ‘act-of-God bond’, or simply CAT bond. A catastrophe bond issued by a special-purpose-vehicle (SPV) company, and then sold to the investor. The revenue from this transaction is joined with the money (premium) from the sponsor company and then invested in other product. If a catastrophe happened before the time-of-maturity, cash flow from the SPV to the investor will discounted or stopped, and the cash flow is paid to the sponsor company to compensate their loss because of this catastrophe event. When we consider the earthquake only, the amount of discounted cash flow could determine based on the earthquake’s magnitude. A case study with Indonesian earthquake magnitude data show that the probability of maximum magnitude can model by generalized extreme value (GEV) distribution. In pricing this catastrophe bond, we assumed stochastic interest rate that following the Cox-Ingersoll-Ross (CIR) interest rate model. We develop formulas for pricing three types of catastrophe bond, namely zero coupon bonds, ‘coupon only at risk’ bond, and ‘principal and coupon at risk’ bond. Relationship between price of the catastrophe bond and CIR model’s parameter, GEV’s parameter, percentage of coupon, and discounted cash flow rule then explained via Monte Carlo simulation.

  5. The effect of rapid and sustained decompression on barotrauma in juvenile brook lamprey and Pacific lamprey: implications for passage at hydroelectric facilities

    SciTech Connect

    Colotelo, Alison HA; Pflugrath, Brett D.; Brown, Richard S.; Brauner, Colin J.; Mueller, Robert P.; Carlson, Thomas J.; Deng, Zhiqun; Ahmann, Martin L.; Trumbo, Bradly A.

    2012-10-01

    Fish passing downstream through hydroelectric facilities may pass through hydroturbines where they experience a rapid decrease in barometric pressure as they pass by turbine blades, which can lead to barotraumas including swim bladder rupture, exopthalmia, emboli, and hemorrhaging. In juvenile Chinook salmon, the main mechanism for injury is thought to be expansion of existing gases (particularly those present in the swim bladder) and the rupture of the swim bladder ultimately leading to exopthalmia, emboli and hemorrhaging. In fish that lack a swim bladder, such as lamprey, the rate and severity of barotraumas due to rapid decompression may be reduced however; this has yet to be extensively studied. Another mechanism for barotrauma can be gases coming out of solution and the rate of this occurrence may vary among species. In this study, juvenile brook and Pacific lamprey acclimated to 146.2 kPa (equivalent to a depth of 4.6 m) were subjected to rapid (<1 sec; brook lamprey only) or sustained decompression (17 minutes) to a very low pressure (13.8 kPa) using a protocol previously applied to juvenile Chinook salmon. No mortality or evidence of barotraumas, as indicated by the presence of hemorrhages, emboli or exopthalmia, were observed during rapid or sustained decompression, nor following recovery for up to 120 h following sustained decompression. In contrast, mortality or injury would be expected for 97.5% of juvenile Chinook salmon exposed to a similar rapid decompression to these very low pressures. Additionally, juvenile Chinook salmon experiencing sustained decompression died within 7 minutes, accompanied by emboli in the fins and gills and hemorrhaging in the tissues. Thus, juvenile lamprey may not be susceptible to barotraumas associated with hydroturbine passage to the same degree as juvenile salmonids, and management of these species should be tailored to their specific morphological and physiological characteristics.

  6. Percutaneous Laser Disc Decompression (PLDD): Experience and Results From Multiple Centers and 19,880 Procedures

    NASA Astrophysics Data System (ADS)

    Paolo Tassi, Gian; Choy, Daniel S. J.; Hellinger, Johannes; Hellinger, Stefan; Lee, Sang-Ho

    2010-05-01

    In mid-February 1986, Peter Ascher and Daniel Choy performed the first Percutaneous Laser Disc Decompression (PLDD) at the Neurosurgical Department, University of Graz, Graz, Austria. It was planned to deliver 1000 joules with a Nd:YAG laser to a herniated L4-5 disc causing sciatica. At 600 joules the procedure was terminated because the pain was gone. Since then, PLDD has spread all over the world, with procedures being performed in the entire spine except for T1-T4 because these discs do not permit percutaneous access with a needle. The success rate has ranged from 70 to 89%, and the complication rate, chiefly discitis, from 0.3 to 1.0%. When successful, return to normal work averages one week. Long term follow-up to 23 years yields a recurrence rate of 4-5%.

  7. Risk of decompression sickness in the presence of circulating microbubbles

    NASA Technical Reports Server (NTRS)

    Kumar, K. Vasantha; Powell, Michael R.

    1993-01-01

    In this study, we examined the association between microbubbles formed in the circulation from a free gas phase and symptoms of altitude decompression sickness (DCS). In a subgroup of 59 males of mean (S.D) age 31.2 (5.8) years who developed microbubbles during exposure to 26.59 kPa (4.3 psi) under simulated extravehicular activities (EVA), symptoms of DCS occurred in 24 (41 percent) individuals. Spencer grade 1 microbubbles occurred in 4 (7 percent), grade 2 in 9 (15 percent), grade 3 in 15 (25 percent), and grade 4 in 31 (53 percent) of subjects. Survival analysis using Cox proportional hazards regression showed that individuals with less than grade 3 CMB showed 2.46 times (95 percent confidence interval = 1.26 to 5.34) higher risk of symptoms. This information is crucial for defining the risk of DCS for inflight Doppler monitoring under space EVA. Altitude decompression sickness (DCS) occurs when there is acute reduction in ambient pressure. The symptoms of DCS are due to the formation of a free gas phase (in the form of gas microbubbles) in tissues during decompression. Musculo-skeletal pain of bends is the commonest form of DCS in altitude exposures. In the space flight environment, there is a risk of DCS when astronauts decompress from the normobaric shuttle pressure into the hypobaric space suit pressure (currently about 29.65 kPa (4.3 psi) for extra-vehicular activities (EVA). This risk is counterbalanced by a judicious combination of prior denitrogenation and staged decompression. Studies of DCS are limited by the duration of the test at reduced pressure. Since only a proportion of subjects tested develop symptoms, the information on DCS is generally incomplete or 'censored'. Many studies employ Doppler ultrasound monitoring of the precordial area for detecting circulating microbubbles (CMB). Although the association between CMB and bends pain is not causal, CMB are frequently monitored during decompression. In this paper, we examine the association

  8. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

    PubMed Central

    Valdivia-Anistro, Jorge A.; Eguiarte-Fruns, Luis E.; Delgado-Sapién, Gabriela; Márquez-Zacarías, Pedro; Gasca-Pineda, Jaime; Learned, Jennifer; Elser, James J.; Olmedo-Alvarez, Gabriela; Souza, Valeria

    2016-01-01

    The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the

  9. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem.

    PubMed

    Valdivia-Anistro, Jorge A; Eguiarte-Fruns, Luis E; Delgado-Sapién, Gabriela; Márquez-Zacarías, Pedro; Gasca-Pineda, Jaime; Learned, Jennifer; Elser, James J; Olmedo-Alvarez, Gabriela; Souza, Valeria

    2015-01-01

    The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6-15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the

  10. The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth

    NASA Astrophysics Data System (ADS)

    Amaro-Seoane, Pau; Preto, Miguel

    2011-05-01

    One of the most interesting sources of gravitational waves (GWs) for LISA is the inspiral of compact objects on to a massive black hole (MBH), commonly referred to as an 'extreme-mass ratio inspiral' (EMRI). The small object, typically a stellar black hole, emits significant amounts of GW along each orbit in the detector bandwidth. The slowly, adiabatic inspiral of these sources will allow us to map spacetime around MBHs in detail, as well as to test our current conception of gravitation in the strong regime. The event rate of this kind of source has been addressed many times in the literature and the numbers reported fluctuate by orders of magnitude. On the other hand, recent observations of the Galactic centre revealed a dearth of giant stars inside the inner parsec relative to the numbers theoretically expected for a fully relaxed stellar cusp. The possibility of unrelaxed nuclei (or, equivalently, with no or only a very shallow cusp, or core) adds substantial uncertainty to the estimates. Having this timely question in mind, we run a significant number of direct-summation N-body simulations with up to half a million particles to calibrate a much faster orbit-averaged Fokker-Planck code. We show that, under quite generic initial conditions, the time required for the growth of a relaxed, mass segregated stellar cusp is shorter than a Hubble time for MBHs with M• <~ 5 × 106 Modot (i.e. nuclei in the range of LISA). We then investigate the regime of strong mass segregation (SMS) for models with two different stellar mass components. Given the most recent stellar mass normalization for the inner parsec of the Galactic centre, SMS has the significant impact of boosting the EMRI rates by a factor of ~10 in comparison to what would result from a 7/4-Bahcall and Wolf cusp resulting in ~250 events per Gyr per Milky Way type galaxy. Such an intrinsic rate should translate roughly into ~102-7 × 102 sbh's (EMRIs detected by LISA over a mission lifetime of 2 or 5 years

  11. Carbon tetrachloride under extreme conditions.

    PubMed

    Pravica, Michael; Sneed, Daniel; Wang, Yonggang; Smith, Quinlan; Subrahmanyam, Garimella

    2014-05-21

    We report on three experiments on carbon tetrachloride subjected to extreme conditions. In the first experiment, Raman spectra of CCl4 were acquired up to 28 GPa. Evidence was observed for at least two new phases of CCl4 above 14 GPa (phase VI) and above 22 GPa (phase VII). Decompression of the sample showed no evidence of pressure-induced decomposition. In the second experiment, a synchrotron x-ray diffraction study was performed up to 30 GPa verifying phase V and potential phases above 14 (VI) and 22 GPa (VII), respectively. In the third study, we examined irradiated CCl4 using synchrotron infrared spectroscopy to reduce fluorescent contamination. Some sort of carbon allotrope appears as a byproduct suggesting the following reaction with hard x-rays: CCl4+ hν → C + 2Cl2. PMID:24852546

  12. Carbon tetrachloride under extreme conditions

    SciTech Connect

    Pravica, Michael Sneed, Daniel; Wang, Yonggang; Smith, Quinlan; Subrahmanyam, Garimella

    2014-05-21

    We report on three experiments on carbon tetrachloride subjected to extreme conditions. In the first experiment, Raman spectra of CCl{sub 4} were acquired up to 28 GPa. Evidence was observed for at least two new phases of CCl{sub 4} above 14 GPa (phase VI) and above 22 GPa (phase VII). Decompression of the sample showed no evidence of pressure-induced decomposition. In the second experiment, a synchrotron x-ray diffraction study was performed up to 30 GPa verifying phase V and potential phases above 14 (VI) and 22 GPa (VII), respectively. In the third study, we examined irradiated CCl{sub 4} using synchrotron infrared spectroscopy to reduce fluorescent contamination. Some sort of carbon allotrope appears as a byproduct suggesting the following reaction with hard x-rays: CCl{sub 4}+ hν → C + 2Cl{sub 2}.

  13. Who are the Best Candidates for Decompressive Surgery and Spine Stabilization in Patients With Metastatic Spinal Cord Compression?

    PubMed Central

    Lei, Mingxing; Li, Jianjie; Liu, Yaosheng; Jiang, Weigang; Liu, Shubin; Zhou, Shiguo

    2016-01-01

    Study Design. A retrospective study. Objective. This study aims to develop a new scoring system that can guild surgeons to select the best candidates for decompressive surgery in patients with metastatic spinal cord compression (MSCC). Summary of Background Data. Predicting survival and functional outcome is essential when selecting the individual treatment for patients with MSCC. The criteria for identifying MSCC patients who are most likely to benefit from decompressive surgery remain unclear. Methods. We retrospectively analyzed 12 preoperative characteristics for postoperative survival in a series of 206 patients with MSCC who were operated with decompressive surgery and spine stabilization. Characteristics significantly associated with survival in the multivariate analysis were included in the scoring system. Postoperative function outcome was also analyzed on the basis of the scoring system. Results. According to the multivariate analysis, primary site (P < 0.01), preoperative ambulatory status (P < 0.01), visceral metastases (P < 0.01), preoperative chemotherapy (P = 0.02), and bone metastasis at cancer diagnosis (P = 0.03) had a significant impact on postoperative survival and were included in the scoring system. According to the prognostic scores, which ranged from 0 to 10 points, three risk groups were designed: 0 to 2, 3 to 5, and 6 to 10 points. The corresponding 6 months survival rates were 8.2%, 56.5%, and 91.5%, respectively (P < 0.01), and postoperative ambulatory rates were 35.7%, 73.3%, and 95.9%, respectively (P < 0.01). Conclusion. We present a new scoring system for predicting survival and function outcome of MSCC patients after surgical decompression and spine stabilization. This new scoring system can help surgeons select the best candidates for surgical treatment. Level of Evidence: 4 PMID:26937605

  14. Fluoxetine Protection in Decompression Sickness in Mice is Enhanced by Blocking TREK-1 Potassium Channel with the "spadin" Antidepressant.

    PubMed

    Vallée, Nicolas; Lambrechts, Kate; De Maistre, Sébastien; Royal, Perrine; Mazella, Jean; Borsotto, Marc; Heurteaux, Catherine; Abraini, Jacques; Risso, Jean-Jacques; Blatteau, Jean-Eric

    2016-01-01

    In mice, disseminated coagulation, inflammation, and ischemia induce neurological damage that can lead to death. These symptoms result from circulating bubbles generated by a pathogenic decompression. Acute fluoxetine treatment or the presence of the TREK-1 potassium channel increases the survival rate when mice are subjected to an experimental dive/decompression protocol. This is a paradox because fluoxetine is a blocker of TREK-1 channels. First, we studied the effects of an acute dose of fluoxetine (50 mg/kg) in wild-type (WT) and TREK-1 deficient mice (knockout homozygous KO and heterozygous HET). Then, we combined the same fluoxetine treatment with a 5-day treatment protocol with spadin, in order to specifically block TREK-1 activity (KO-like mice). KO and KO-like mice were regarded as antidepressed models. In total, 167 mice (45 WTcont 46 WTflux 30 HETflux and 46 KOflux) constituting the flux-pool and 113 supplementary mice (27 KO-like 24 WTflux2 24 KO-likeflux 21 WTcont2 17 WTno dive) constituting the spad-pool were included in this study. Only 7% of KO-TREK-1 treated with fluoxetine (KOflux) and 4% of mice treated with both spadin and fluoxetine (KO-likeflux) died from decompression sickness (DCS) symptoms. These values are much lower than those of WT control (62%) or KO-like mice (41%). After the decompression protocol, mice showed significant consumption of their circulating platelets and leukocytes. Spadin antidepressed mice were more likely to exhibit DCS. Nevertheless, mice which had both blocked TREK-1 channels and fluoxetine treatment were better protected against DCS. We conclude that the protective effect of such an acute dose of fluoxetine is enhanced when TREK-1 is inhibited. We confirmed that antidepressed models may have worse DCS outcomes, but concomitant fluoxetine treatment not only decreased DCS severity but increased the survival rate. PMID:26909044

  15. Isentropic decompression of fluids from crustal and mantle pressures

    NASA Technical Reports Server (NTRS)

    Kieffer, S. W.; Delany, J. M.

    1979-01-01

    Criteria are derived according to which the flow of single-phase magmatic fluids and the rarefaction expansion of low-viscosity liquids and gases may be considered approximately isentropic. Graphs of entropy vs. density with contours of constant pressure and mass fraction are used to examine the possible thermodynamic histories of H2O and CO2 decompressing isentropically from crustal and upper mantle pressures; these graphs offer a simple visual representation of a number of thermodynamic variables involved in isentropic processes. It is shown how the graphs can be used to examine the behavior of volatiles that (1) ascend in volcanic systems originating at different depths within the earth, and (2) decompress from a shock Hugoniot state. Entropy-density graphs are presented separately for H2O and CO2.

  16. Prevention of decompression sickness during a simulated space docking mission

    NASA Technical Reports Server (NTRS)

    Cooke, J. P.; Bollinger, R. R.; Richardson, B.

    1975-01-01

    This study has shown that repetitive exchanges between the Apollo space vehicle atmosphere of 100% oxygen at 5 psia (258 torr) and the Soyuz spacecraft atmosphere of 30% oxygen-70% nitrogen at 10 psia (533 torr), as simulated in altitude chambers, will not likely result in any form of decompression sickness. This conclusion is based upon the absence of any form of bends in seven crewmen who participated in 11 tests distributed over three 24-h periods. During each period, three transfers from the 5 to the 10 psia environments were performed by simulating passage through a docking module which served as an airlock where astronauts and cosmonauts first adapted to each other's cabin gases and pressures before transfer. Biochemical tests, subjective fatigue scores, and the complete absence of any form of pain were also indicative that decompression sickness should not be expected if this spacecraft transfer schedule is followed.

  17. Denitrogenation interruptions with air. [resulting in decompression sickness

    NASA Technical Reports Server (NTRS)

    Cooke, J. P.

    1976-01-01

    A 3-h denitrogenation period at ground-level pressure with 95% O2-5% N2, with an air interruption of 5 min or more and matched with additional denitrogenation time equal to the interruption, will later result occasionally in altitude decompression sickness ('bends') during a 2-h decompression exposure at 3.8 psia (10,058 m equivalent) with 92% O2- 8% N2. Thus the equal time or 'mirror-image' make-up time for loss of denitrogenation did not prevent bends 7 times in 17 subjects during 71 exposures with air interruptions; on the other hand, no case of bends was reported after uninterrupted denitrogenation periods. Nitrogen-loading during the interruptive period is believed to resupply the bends sites with additional nitrogen, which re-establishes conditions favoring a return to a high incidence of bends.

  18. Acute obstructive hydrocephalus complicating decompression surgery of the craniovertebral junction.

    PubMed

    Ohya, Junichi; Chikuda, Hirotaka; Nakatomi, Hirofumi; Sakamoto, Ryuji; Saito, Nobuhito; Tanaka, Sakae

    2016-01-01

    Obstructive hydrocephalus has been described as a rare complication following foramen magnum decompression for Chiari malformation. However, there are few reports of obstructive hydrocephalus after spinal surgery for other pathologies of the craniovertebral junction (CVJ). The authors herein report a 52-year-old female with achondroplasia presenting with an 8-month history of myelopathy due to spinal cord compression at CVJ. She underwent resection of the C1 posterior arch and part of the edge of the occipital bone. A computed tomography (CT) scan obtained 1-week after the surgery revealed bilateral infratentorial fluid collection. The patient was first managed conservatively; however, on the 17(th) day, her consciousness level showed sudden deterioration. Emergency CT demonstrated marked hydrocephalus due to obstruction of the cerebral aqueduct. Acute obstructive hydrocephalus can occur late after decompression surgery at the CVJ, and thus should be included in the differential diagnosis of a deteriorating mental status. PMID:27366268

  19. Acute obstructive hydrocephalus complicating decompression surgery of the craniovertebral junction

    PubMed Central

    Ohya, Junichi; Chikuda, Hirotaka; Nakatomi, Hirofumi; Sakamoto, Ryuji; Saito, Nobuhito; Tanaka, Sakae

    2016-01-01

    Obstructive hydrocephalus has been described as a rare complication following foramen magnum decompression for Chiari malformation. However, there are few reports of obstructive hydrocephalus after spinal surgery for other pathologies of the craniovertebral junction (CVJ). The authors herein report a 52-year-old female with achondroplasia presenting with an 8-month history of myelopathy due to spinal cord compression at CVJ. She underwent resection of the C1 posterior arch and part of the edge of the occipital bone. A computed tomography (CT) scan obtained 1-week after the surgery revealed bilateral infratentorial fluid collection. The patient was first managed conservatively; however, on the 17th day, her consciousness level showed sudden deterioration. Emergency CT demonstrated marked hydrocephalus due to obstruction of the cerebral aqueduct. Acute obstructive hydrocephalus can occur late after decompression surgery at the CVJ, and thus should be included in the differential diagnosis of a deteriorating mental status. PMID:27366268

  20. Urgent Intracranial Carotid Artery Decompression after Penetrating Head Injury

    PubMed Central

    Kim, Seong Joon

    2013-01-01

    We describe a case of intracranial carotid artery occlusion due to penetrating craniofacial injury by high velocity foreign body that was relieved by decompressive surgery. A 46-year-old man presented with a penetrating wound to his face. A piece of an electric angular grinder disc became lodged in the anterior skull base. Computed tomography revealed that the disc had penetrated the unilateral paraclinoid and suprasellar areas without flow of the intracranial carotid artery on the lesion side. The cavernous sinus was also compromised. Removal of the anterior clinoid process reopened the carotid blood flow, and the injection of glue into the cavernous sinus restored complete hemostasis during extraction of the fragment from the face. Digital subtraction angiography revealed complete recanalization of the carotid artery without any evidence of dissection. Accurate diagnosis regarding the extent of the compromised structures and urgent decompressive surgery with adequate hemostasis minimized the severity of penetrating damage in our patient. PMID:23634269

  1. Report on computation of repetitive hyperbaric-hypobaric decompression tables

    NASA Technical Reports Server (NTRS)

    Edel, P. O.

    1975-01-01

    The tables were constructed specifically for NASA's simulated weightlessness training program; they provide for 8 depth ranges covering depths from 7 to 47 FSW, with exposure times of 15 to 360 minutes. These tables were based up on an 8 compartment model using tissue half-time values of 5 to 360 minutes and Workmanline M-values for control of the decompression obligation resulting from hyperbaric exposures. Supersaturation ratios of 1.55:1 to 2:1 were used for control of ascents to altitude following such repetitive dives. Adequacy of the method and the resultant tables were determined in light of past experience with decompression involving hyperbaric-hypobaric interfaces in human exposures. Using these criteria, the method showed conformity with empirically determined values. In areas where a discrepancy existed, the tables would err in the direction of safety.

  2. Predictive modeling of altitude decompression sickness in humans

    NASA Technical Reports Server (NTRS)

    Kenyon, D. J.; Hamilton, R. W., Jr.; Colley, I. A.; Schreiner, H. R.

    1972-01-01

    The coding of data on 2,565 individual human altitude chamber tests is reported as part of a selection procedure designed to eliminate individuals who are highly susceptible to decompression sickness, individual aircrew members were exposed to the pressure equivalent of 37,000 feet and observed for one hour. Many entries refer to subjects who have been tested two or three times. This data contains a substantial body of statistical information important to the understanding of the mechanisms of altitude decompression sickness and for the computation of improved high altitude operating procedures. Appropriate computer formats and encoding procedures were developed and all 2,565 entries have been converted to these formats and stored on magnetic tape. A gas loading file was produced.

  3. Towards Probablistic Assessment of Hypobaric Decompression Sickness Treatment

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Abercromby, A. F.; Feiveson, A. H.; Gernhardt, M. L.; Norcross, J. R.; Ploutz-Snyder, R.; Wessel, J. H., III

    2013-01-01

    INTRODUCTION: Pressure, oxygen (O2), and time are the pillars to effective treatment of decompression sickness (DCS). The NASA DCS Treatment Model links a decrease in computed bubble volume to the resolution of a symptom. The decrease in volume is realized in two stages: a) during the Boyle's Law compression and b) during subsequent dissolution of the gas phase by the O2 window. METHODS: The cumulative distribution of 154 symptoms that resolved during repressurization was described with a log-logistic density function of pressure difference (deltaP as psid) associated with symptom resolution and two other explanatory variables. The 154 symptoms originated from 119 cases of DCS during 969 exposures in 47 different altitude tests. RESULTS: The probability of symptom resolution [P(symptom resolution)] = 1 / (1+exp(- (ln(deltaP) - 1.682 + 1.089×AMB - 0.00395×SYMPTOM TIME) / 0.633)), where AMB is 1 when the subject ambulated as part of the altitude exposure or else 0 and SYMPTOM TIME is the elapsed time in min from start of the altitude exposure to recognition of a DCS symptom. The P(symptom resolution) was estimated from computed deltaP from the Tissue Bubble Dynamics Model based on the "effective" Boyle's Law change: P2 - P1 (deltaP, psid) = P1×V1/V2 - P1, where V1 is the computed volume of a spherical bubble in a unit volume of tissue at low pressure P1 and V2 is computed volume after a change to a higher pressure P2. V2 continues to decrease through time at P2, at a faster rate if 100% ground level O2 was breathed. The computed deltaP is the effective treatment pressure at any point in time as if the entire ?deltaP was just from Boyle's Law compression. DISCUSSION: Given the low probability of DCS during extravehicular activity and the prompt treatment of a symptom with options through the model it is likely that the symptom and gas phase will resolve with minimum resources and minimal impact on astronaut health, safety, and productivity.

  4. Visualization and void fraction measurement of decompressed boiling flow in a capillary tube

    NASA Astrophysics Data System (ADS)

    Asano, H.; Murakawa, H.; Takenaka, N.; Takiguchi, K.; Okamoto, M.; Tsuchiya, T.; Kitaide, Y.; Maruyama, N.

    2011-09-01

    A capillary tube is often used as a throttle for a refrigerating cycle. Subcooled refrigerant usually flows from a condenser into the capillary tube. Then, the refrigerant is decompressed along the capillary tube. When the static pressure falls below the saturation pressure for the liquid temperature, spontaneous boiling occurs. A vapor-liquid two-phase mixture is discharged from the tube. In designing a capillary tube, it is necessary to calculate the flow rate for given boundary conditions on pressure and temperature at the inlet and exit. Since total pressure loss is dominated by frictional and acceleration losses during two-phase flow, it is first necessary to specify the boiling inception point. However, there will be a delay in boiling inception during decompressed flow. This study aimed to clarify the boiling inception point and two-phase flow characteristics of refrigerant in a capillary tube. Refrigerant flows in a coiled copper capillary tube were visualized by neutron radiography. The one-dimensional distribution of volumetric average void fraction was measured from radiographs through image processing. From the void fraction distribution, the boiling inception point was determined. Moreover, a simplified CT method was successfully applied to a radiograph for cross-sectional measurements. The experimental results show the flow pattern transition from intermittent flow to annular flow that occurred at a void fraction of about 0.45.

  5. Dependency of continental crustal rupture, decompression melt initiation and OCT architecture on lithosphere deformation modes during continental breakup: Numerical experiments

    NASA Astrophysics Data System (ADS)

    Jeanniot, L.; Kusznir, N. J.; Manatschal, G.

    2012-12-01

    During the continental breakup process, the initiation of sea-floor spreading requires both the rupture of the continental crust and the initiation of decompression melting. Using numerical experiments, we investigate how the deformation mode of continental lithosphere thinning and stretching controls the rupture of continental crust and lithospheric mantle, the onset of decompression melting and their relative timing. We use a two dimensional finite element viscous flow model to describe lithosphere and asthenosphere deformation. This flow field is used to advect lithosphere and asthenosphere material and temperature. Decompression melting is predicted using the parameterization scheme of Katz et al. (2003). Consistent with the observations of deformation processes occurring at slow spreading ocean ridges (Cannat, 1996), we assume that the topmost continental and oceanic lithosphere, corresponding to the cooler brittle seismogenic layer, deforms by extensional faulting (which we approximate to pure-shear deformation) and magmatic intrusion. Beneath this topmost lithosphere layer approximately 15-20 km thick, we assume that deformation occurs in response to passive upwelling and thermal and melt buoyancy driven small-scale convection. The relative contribution of these deformation components is parameterised by the ratio Vz/Vx, where Vx is the half spreading rate applied to the topmost lithosphere deformation and Vz is the upwelling velocity associated with the small scale convection. We use a series of numerical experiments to investigate the dependency of continental crust and lithosphere rupture, decompression melt initiation, rifted margin ocean-continent transition architecture and subsidence history on the half-spreading rate Vx, buoyancy driven upwelling rate Vz, the ratio Vz/Vx and upper lithosphere pure-shear width W. Based on the numerical experiment results we explore a polyphase evolution of deformation modes leading to continental breakup, sea

  6. Sidenafil Pre-Treatment Promotes Decompression Sickness in Rats

    PubMed Central

    Blatteau, Jean-Eric; Brubakk, Alf O.; Gempp, Emmanuel; Castagna, Olivier; Risso, Jean-Jacques; Vallée, Nicolas

    2013-01-01

    Vascular bubble formation after decompression contributes to endothelial injuries which form the basis for the development of decompression sickness (DCS). Nitric oxide (NO) is a powerful vasodilator that contributes to vessel homeostasis. It has been shown that NO-releasing agent may reduce bubble formation and prevent serious decompression sickness. The use of sildenafil, a well-known, phosphodiesterase-5 blocker, which act by potentiating the vasodilatory effect on smooth muscle relaxation, has never been studied in DCS. The purpose of the present study was to evaluate the clinical effects of sildenafil pre-treatment on DCS in a rat model. 67 rats were subjected to a simulated dive at 90 msw for 45 min before staged decompression. The experimental group received 10 mg/kg of sildenafil one hour before exposure (n = 35) while controls were not treated (n = 32). Clinical assessment took place over a period of 30 min after surfacing. At the end, blood samples were collected for blood cells counts and the level of circulating bubbles in the right cavities was quantified. There were significantly more manifestations of DCS in the sildenafil group than in the controls (34.3% vs 6.25%, respectively, p = 0.012). Platelet count was more reduced in treated rats than in controls (−21.7% vs −7%, respectively, p = 0.029), whereas bubble grades did not differ between groups. We concluded that pre-treatment with sildenafil promotes the onset and severity of neurological DCS. When considering the use of phosphodiesterase-5 blockers in the context of diving, careful discussion with physician should be recommended. PMID:23580342

  7. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Decompression Tables A Appendix A to Subpart S of Part 1926..., Caissons, Cofferdams and Compressed Air Pt. 1926, Subpt. S, App. A Appendix A to Subpart S of Part 1926... pressure p.s.i.g. Working period hours 1/2 1 11/2 2 3 4 5 6 7 8 Over 8 9 to 12 3 3 3 3 3 3 3 3 3 3 3 14 6...

  8. [Arthroscopic sub-acromial decompression. Comments on indications and surgical technique].

    PubMed

    Hartig, A; Rojczyk, M

    1993-02-01

    Between January 1989 and December 1991 614 arthroscopic subacromial decompressions were performed for impingement syndromes. The first 100 cases represented our learning curve. The first 74 of the remaining 514 cases were available for evaluation and form the basis of the results presented here. Twenty (27.02%) patients were rated stage II in Neer's classification and 54 (72.98%) were rated stage III, 33 (44.59%) of them with a small full-thickness tear (less than 1 cm) and 21 (28.37%) with larger defects. Patients were evaluated pre- and postoperatively utilizing the ULCA shoulder score. The average follow-up was 7.9 months. The overall results were satisfactory in 67 cases (90.5%) and unsatisfactory in 7 cases (9.5%). Within the satisfactory group, 28 results (37.8%) were rated excellent and 39 (52.7%) were rated good. In the unsatisfactory group four results (5.4%) were rated fair and three (4.1%) poor. The results in advanced stage III (n = 21), with an average follow-up of 8.4 months, were satisfactory in 20 cases (excellent in 8 and good in 12) and unsatisfactory in one case. It is concluded that arthroscopic subacromial decompression is an effective treatment for both stage II and III impingement syndromes, producing acceptable results that are comparable to those of open procedures. Technically, it seems necessary to perform synovectomy of the ventral synovia in the glenohumeral joint, to resect the coracoacromial ligament completely and also to remove calcifications completely. Depending on the findings of a preoperative sonographic examination of the shoulder joint, the extent of the acromioplasty may be minimized. PMID:8451648

  9. Process for decompression control in internal combustion engine and apparatus therefor

    SciTech Connect

    Matsuki, I.; Kamiya, N.; Ikeda, T.; Takagi, Y.; Iizuka, Y.; Yamaguchi, Y.; Funai, H.; Terasawa; Tasaka, S.

    1986-05-27

    A process is described for use in controlled decompression in internal combustion engine operation used for driving compressors, electric generator, and the like, comprising the steps of starting the engine with the decompression control engaged and the engine operating decompressed, increasing the speed of the engine with the decompression control engaged and the engine operating decompressed until the engine reaches a first predetermined speed, while increasing the engine speed above the first predetermined speed disengaging the decompression control to a first stage of disengagement to operate the engine compressed, while the engine is operating compressed, increasing the engine speed to an operating speed above the first predetermined speed and disengaging the decompression control to a second stage of disengagement while continuing to operate the engine compressed and, after the engine has completed the compressed operation with the decompression control disengaged, reducing the engine speed to a second predetermined speed above the first predetermined speed but below the operating speed, reengaging the decompression control and, with the engine operating decompressed further reducing the speed of the engine until the engine stops.

  10. Musculoskeletal-induced Nucleation in Altitude Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Pollock, N. W.; Natoli, M. J.; Conkin, J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    Musculoskeletal activity has the potential to both improve and compromise decompression safety. Exercise enhances inert gas elimination during oxygen breathing prior to decompression (prebreathe), but it may also promote bubble nuclei formation (nucleation), which can lead to gas phase separation and bubble growth and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity and the level of tissue supersaturation may be critical to the net effect. There are limited data available to evaluate cost-benefit relationships. Understanding the relationship is important to improve our understanding of the underlying mechanisms of nucleation in exercise prebreathe protocols and to quantify risk in gravity and microgravity environments. Data gathered during NASA's Prebreathe Reduction Program (PRP) studies combined oxygen prebreathe and exercise followed by low pressure (4.3 psi; altitude equivalent of 30,300 ft [9,235 m]) microgravity simulation to produce two protocols used by astronauts preparing for extravehicular activity. Both the Phase II/CEVIS (cycle ergometer vibration isolation system) and ISLE (in-suit light exercise) trials eliminated ambulation to more closely simulate the microgravity environment. The CEVIS results (35 male, 10 female) serve as control data for this NASA/Duke study to investigate the influence of ambulation exercise on bubble formation and the subsequent risk of DCS.

  11. White matter changes linked to visual recovery after nerve decompression

    PubMed Central

    Paul, David A.; Gaffin-Cahn, Elon; Hintz, Eric B.; Adeclat, Giscard J.; Zhu, Tong; Williams, Zoë R.; Vates, G. Edward; Mahon, Bradford Z.

    2015-01-01

    The relationship between the integrity of white matter tracts and cortical function in the human brain remains poorly understood. Here we use a model of reversible white matter injury, compression of the optic chiasm by tumors of the pituitary gland, to study the structural and functional changes that attend spontaneous recovery of cortical function and visual abilities after surgical tumor removal and subsequent decompression of the nerves. We show that compression of the optic chiasm leads to demyelination of the optic tracts, which reverses as quickly as 4 weeks after nerve decompression. Furthermore, variability across patients in the severity of demyelination in the optic tracts predicts visual ability and functional activity in early cortical visual areas, and pre-operative measurements of myelination in the optic tracts predicts the magnitude of visual recovery after surgery. These data indicate that rapid regeneration of myelin in the human brain is a significant component of the normalization of cortical activity, and ultimately the recovery of sensory and cognitive function, after nerve decompression. More generally, our findings demonstrate the utility of diffusion tensor imaging as an in vivo measure of myelination in the human brain. PMID:25504884

  12. Decryption-decompression of AES protected ZIP files on GPUs

    NASA Astrophysics Data System (ADS)

    Duong, Tan Nhat; Pham, Phong Hong; Nguyen, Duc Huu; Nguyen, Thuy Thanh; Le, Hung Duc

    2011-10-01

    AES is a strong encryption system, so decryption-decompression of AES encrypted ZIP files requires very large computing power and techniques of reducing the password space. This makes implementations of techniques on common computing system not practical. In [1], we reduced the original very large password search space to a much smaller one which surely containing the correct password. Based on reduced set of passwords, in this paper, we parallel decryption, decompression and plain text recognition for encrypted ZIP files by using CUDA computing technology on graphics cards GeForce GTX295 of NVIDIA, to find out the correct password. The experimental results have shown that the speed of decrypting, decompressing, recognizing plain text and finding out the original password increases about from 45 to 180 times (depends on the number of GPUs) compared to sequential execution on the Intel Core 2 Quad Q8400 2.66 GHz. These results have demonstrated the potential applicability of GPUs in this cryptanalysis field.

  13. Protective Effects of Fluoxetine on Decompression Sickness in Mice

    PubMed Central

    Blatteau, Jean-Eric; Barre, Sandrine; Pascual, Aurelie; Castagna, Olivier; Abraini, Jacques H.; Risso, Jean-Jacques; Vallee, Nicolas

    2012-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS) that can result in central nervous system disorders or even death. Bubbles alter the vascular endothelium and activate blood cells and inflammatory pathways, leading to a systemic pathophysiological process that promotes ischemic damage. Fluoxetine, a well-known antidepressant, is recognized as having anti-inflammatory properties at the systemic level, as well as in the setting of cerebral ischemia. We report a beneficial clinical effect associated with fluoxetine in experimental DCS. 91 mice were subjected to a simulated dive at 90 msw for 45 min before rapid decompression. The experimental group received 50 mg/kg of fluoxetine 18 hours before hyperbaric exposure (n = 46) while controls were not treated (n = 45). Clinical assessment took place over a period of 30 min after surfacing. At the end, blood samples were collected for blood cells counts and cytokine IL-6 detection. There were significantly fewer manifestations of DCS in the fluoxetine group than in the controls (43.5% versus 75.5%, respectively; p = 0.004). Survivors showed a better and significant neurological recovery with fluoxetine. Platelets and red cells were significantly decreased after decompression in controls but not in the treated mice. Fluoxetine reduced circulating IL-6, a relevant marker of systemic inflammation in DCS. We concluded that fluoxetine decreased the incidence of DCS and improved motor recovery, by limiting inflammation processes. PMID:23145072

  14. Foramen Magnum Decompression and Duraplasty is Superior to Only Foramen Magnum Decompression in Chiari Malformation Type 1 Associated with Syringomyelia in Adults

    PubMed Central

    Berkman, Mehmet Zafer; Ünal, Emre; Akpınar, Elif; Gök, Şevki; Orakdöğen, Metin; Aydın, Salih

    2015-01-01

    Study Design Retrospective cohort study. Purpose To compare surgical results of foramen magnum decompression with and without duraplasty in Chiari malformation type 1 (CM-1) associated syringomyelia (SM). Overview of Literature The optimal surgical treatment of CM-1 associated with SM is unclear. Methods Twenty-five cases of CM-1 with SM were included. There were 12 patients (48%) in the non-duraplasty group and 13 patients (52%) in the duraplasty group. The rate of improvement, state of postoperative SM size, amount of tonsillar herniation, preoperative symptom duration, complications and reoperation rates were analysed. Results The rate of clinical improvement was significantly higher with duraplasty (84.6%) than without (33.3%, p <0.05). The rate of postoperative syrinx regression was significantly higher in the duraplasty group (84.6%) than in the non-duraplasty group (33.3%, p <0.05). One case in the duraplasty group needed a reoperation compared with five cases in the non-duraplasty group (p =0.059). Conclusions Duraplasty is superior to non-duraplasty in CM-1 associated with SM despite a slightly higher complication rate. PMID:26435790

  15. A mechanism for the reduction in risk of decompression sickness in microgravity environment

    NASA Technical Reports Server (NTRS)

    Powell, Michael R.

    1993-01-01

    There is an apparent reduction in the incidence of decompression sickness reported by astronauts (from both the USA and the USSR) during extravehicular activity (EVA). The expected incidence, based on studies conducted under unit gravity conditions in Earth-based laboratories, is greater than that encountered during EVA. A biophysical explanation has been proposed for this difference based upon the mechanism of stress-assisted nucleation. Since the partial pressure ratio at which this gas phase forms is considerably smaller in living systems that in quiescent in vitro models, it was proposed that mechanical forces are involved. In that the lower extremities of astronautics are not gravitationally loaded in microgravity, it is possible that tissue gas micronuclei are but minimally regenerated. Most likely, gas micronuclei formed on Earth (by ambulation under 1 g conditions) would be eventually depleted. In a crossover study, 20 individuals were decompressed--from 1 ATA to 0.43 ATA for 3 hours--following either being fully ambulatory at unit gravity or following being hypokinetic and adynamic (simulated microgravity of 3-day bed rest). The subjects were monitored for gas phase formation by means of precordial Doppler monitoring. The results indicate a reduction in whole body gas phase formation in individuals who were bed rested as compared with themselves when fully ambulatory (p = 0.02). In hypokinetic individuals, the protection conferred was equivalent to an extra 175 minutes of oxygen prebreathe. These results are compatible with a hypothesis relating stress-assisted nucleation to the continual formation of tissue gas micronuclei and their gradual depletion with hypokinesia.

  16. Outcome of microvascular decompression for trigeminal neuralgia treated with the stitched sling retraction technique.

    PubMed

    Masuoka, Jun; Matsushima, Toshio; Inoue, Kouhei; Nakahara, Yukiko; Takase, Yukinori; Kawashima, Masatou

    2015-04-01

    The purpose of this retrospective study was to describe and evaluate the long-term outcome of microvascular decompression (MVD) with the stitched sling retraction technique for treating trigeminal neuralgia (TN). Between January 2007 and December 2012, 50 patients with idiopathic TN underwent MVD using the stitched sling retraction technique at our institution. The median follow-up period was 5.2 years (range, 1.8-6.8 years). Using Kaplan-Meier analysis, the rates of complete pain relief without medications were 88% at 1 year and 83% at 5 years. Recurrence was noted in two patients, and one patient was re-treated using a complementary procedure for pain relief. Although transient complications were observed in seven patients, no permanent neurological deficit was observed. We conclude that the stitched sling retraction technique is a safe and effective treatment for TN and maintains substantial pain relief and low recurrence rates over a long period of time. PMID:25663308

  17. Extreme rates of riverbank erosion of the high bluff formed by the ice-rich syngenetic permafrost (yedoma), Itkillik River, Northern Alaska

    NASA Astrophysics Data System (ADS)

    Kanevskiy, M. Z.; Shur, Y.; Fortier, D.; Jorgenson, T.; Stephani, E.; Strauss, J.

    2013-12-01

    the wedge ice was exposed. This block-fall affected the area of approximately 800 m2, and the volume of frozen soil and ice involved in the block-fall was about 15,000 m3. The riverbank retreat due to thermal erosion and/or thermal denudation, measured from August 2007 to August 2011, varied from less than 10 to almost 100 m. An estimated retreat rate average for the whole 680 m long bluff was 11.4 m/year, but for the most actively eroded central part of the bluff (150 m long) it was 20.3 m/year, ranging from 16 to 24 m/year. During these 4 years, about 650,000 m3 of ice and organic-rich frozen soil were transported to the river from the retreating bank (more than 160,000 m3/year). Analysis of aerial photographs (1948-1979) and satellite images (1974-2013) showed that the riverbank was relatively stable till July 1995, when the Itkillik River changed its course and triggered extremely active thermal erosion. The total retreat of the riverbank in 1995-2010 varied from 180 to 280 m, which means that the average retreat rate for the most actively eroded part of the riverbank reached almost 19 m/year. Such a high rate of riverbank erosion over a long time period has not been reported before for any permafrost regions of Eurasia and North America.

  18. Twisting Tourniquet© Technique: introducing Schnogh, a novel device and its effectiveness in treating primary and secondary lymphedema of extremities

    PubMed Central

    Chanwimalueang, Narumon; Ekataksin, Wichai; Piyaman, Parkpoom; Pattanapen, Gedsuda; Hanboon, Borimas K

    2015-01-01

    Twisting Tourniquet© or in Thai “Schnogh” is a new invention for compression therapy of lymphedema. Twisting Tourniquet© Technique (TTT) is totally noninvasive for lymphedema management. After the amazing successful evidence in the first series of 28 patients, we have conducted preliminary studies in lymphedema clinics. It was found that the combination of gradually increasing constriction force by Schnogh until desired pressure was reached and maintained for 15 min, followed by a 5-min release, doing repeatedly this compression-decompression for at least 10 sessions a day, can generate acceptable results. The aim of the study was to evaluate the scientific effectiveness and establish a treatment protocol of TTT proposed as a therapeutic approach for clinical management of lymphedema. During 2006–2013, from over 3500 patients, 647 with primary/secondary lymphedema passed inclusion criteria, 307 for upper, and 340 for lower extremity. In the 5-day course of TTT, each day patients underwent 10 sessions of a 15-min compression followed by a 5-min decompression. Vegan diet was encouraged as an adjuvant therapy. Among lymphedema patients whose spectrum of edema severity ranged from mild to gigantic, TTT yielded an average volume reduction rate (VR) at 50.2% and 55.6%, making the average edema reduction volume attained at 463 and 1856 mL for upper and lower limb, respectively. The uniformed practice by Schnogh which supports a continual compression–decompression maneuver over 3.5 h daily for five consecutive days could induce an average VR at above half of the swelling in extremities of 647 patients. Schnogh is therefore effective in clinical management of lymphedema under TTT treatment of fibroblastic interstitium. PMID:26247407

  19. Twisting Tourniquet(©) Technique: introducing Schnogh, a novel device and its effectiveness in treating primary and secondary lymphedema of extremities.

    PubMed

    Chanwimalueang, Narumon; Ekataksin, Wichai; Piyaman, Parkpoom; Pattanapen, Gedsuda; Hanboon, Borimas K

    2015-10-01

    Twisting Tourniquet(©) or in Thai "Schnogh" is a new invention for compression therapy of lymphedema. Twisting Tourniquet(©) Technique (TTT) is totally noninvasive for lymphedema management. After the amazing successful evidence in the first series of 28 patients, we have conducted preliminary studies in lymphedema clinics. It was found that the combination of gradually increasing constriction force by Schnogh until desired pressure was reached and maintained for 15 min, followed by a 5-min release, doing repeatedly this compression-decompression for at least 10 sessions a day, can generate acceptable results. The aim of the study was to evaluate the scientific effectiveness and establish a treatment protocol of TTT proposed as a therapeutic approach for clinical management of lymphedema. During 2006-2013, from over 3500 patients, 647 with primary/secondary lymphedema passed inclusion criteria, 307 for upper, and 340 for lower extremity. In the 5-day course of TTT, each day patients underwent 10 sessions of a 15-min compression followed by a 5-min decompression. Vegan diet was encouraged as an adjuvant therapy. Among lymphedema patients whose spectrum of edema severity ranged from mild to gigantic, TTT yielded an average volume reduction rate (VR) at 50.2% and 55.6%, making the average edema reduction volume attained at 463 and 1856 mL for upper and lower limb, respectively. The uniformed practice by Schnogh which supports a continual compression-decompression maneuver over 3.5 h daily for five consecutive days could induce an average VR at above half of the swelling in extremities of 647 patients. Schnogh is therefore effective in clinical management of lymphedema under TTT treatment of fibroblastic interstitium. PMID:26247407

  20. [Ogilvie's syndrome. Benefits of repeat colonoscopic decompression on its developmental course].

    PubMed

    Estrada Saiz, R V; Loscos Valerio, J M; Gines Herraiz, M A; Estrada Perez, V

    1995-11-01

    Seven cases of Ogilvie's syndrome are described. In six of ther good recovery was related to repeated endoscopic colonic decompressions. This is the safest and most precise procedure in the diagnosis and treatment of the disease. We emphasize the usefulness of repeated decompressions in the outcome of Ogilvie's syndrome. One of patients in which decompression was not attempted died of a colonic rupture. PMID:8804167

  1. Evaluation of safety of hypobaric decompressions and EVA from positions of probabilistic theory.

    PubMed

    Nikolaev, V P

    1998-01-01

    Formation and subsequent evolution of gas bubbles in blood and tissues of subjects exposed to decompression are casual processes in their nature. Such character of bubbling processes in a body predetermines probabilistic character of decompression sickness (DCS) incidence in divers, aviators and astronauts. Our original probabilistic theory of decompression safety is based on stochastic models of these processes and on the concept of critical volume of a free gas phase in body tissues. From positions of this theory, the probability of DCS incidence during single-stage decompressions and during hypobaric decompressions under EVA in particular, is defined by the distribution of possible values of nucleation efficiency in "pain" tissues and by its critical significance depended on the parameters of a concrete decompression. In the present study the following is shown: 1) the dimensionless index of critical nucleation efficiency for "pain" body tissues is a more adequate index of decompression stress in comparison with Tissue Ratio, TR; 2) a priory the decompression under EVA performed according to the Russian protocol is more safe than decompression under EVA performed in accordance with the U.S. protocol; 3) the Russian space suit operated at a higher pressure and having a higher "rigidity" induces a stronger inhibition of mechanisms of cavitation and gas bubbles formation in tissues of a subject located in it, and by that provides a more considerable reduction of the DCS risk during real EVA performance. PMID:11541599

  2. Use of decompression tubes in the management of excessively large odontogenic keratocyst.

    PubMed

    Garde, Janardan B; Kulkarni, Adwait Uday; Dadhe, Dattaprasad P; Deshmukh, Vikramsinh B

    2012-01-01

    Odontogenic keratocyst (OKC) is a unique cyst because of its locally aggressive behaviour, high recurrence rate and characteristic histological appearance. A radical surgical approach is commonly advocated with morbid and disfiguring results. This approach also presents several reconstructive obstacles especially in anterior mandible. In this case report the authors present a 25-year-old male patient with a large OKC and treatment with decompression followed by enucleation, and chemical cauterisation. This approach though demanding prolonged treatment time and postoperative follow-up decreases the morbidity to a great extent in a young individual. At the same time, it allows an opportunity for the maxillofacial surgeon to preserve the natural dentition, maintain function and safeguard cosmesis. In our case, the authors effectively achieved all the aforementioned objectives. At the same time a radical option of treatment is still left in the armoury if required at a later date. PMID:22605822

  3. [Decompressive craniotomy in the complex intensive treatment of malignant forms of massive ischemic stroke].

    PubMed

    Krylov, V V; Nikitin, A S; Burov, S A; Petrikov, S S; Asratian, S A; Averin, A Iu; Kol'iak, E V

    2013-01-01

    A group of patients with benign course of massive ischemic stroke (MII) without development of the dislocation syndrome and a group of patients with malignant course with development of the hemispheric brain edema with the following transtentorial herniation were singled out. Risk factors for the development of malignant form of MII and its fatal outcomes were specified as lateral dislocation (>7 mm), more than 70% of ischemia size in frontal and parietal lobes and more than 80% - in temporal lobes, the disturbance of wakefulness up to moderate coma or more. Based on these results, it was selected patients for decompressive craniotomy in the affected hemisphere that allowed to reduce the fatality rate by more than twice compared to patients treated without surgery. PMID:23528487

  4. Gender and Decompression Sickness: A Critical Review and Analysis

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The author addressed the following questions: are women at greater risk of decompression sickness and venous gas emboli at certain times in their reproductive cycle, is risk modified by the use of birth control pills (BCP), and is there a difference in overall risk between men and women under the same decompression dose? The summary considers information from the few abstracts and reports that were available. Except for the observation of more Type II DCS in women, particularly in women who fly after diving, there was no compelling evidence of a difference in DCS risk between men and women SCUBA divers. Many women that presented with DCS symptoms seemed to be in or near menses, with statistically fewer cases reported as time increased from menses. There was no compelling evidence that the use of BCP in SCUBA divers increases the risk of DCS. There were insufficient data about VGE from SCUBA diving to make any conclusion about the incidence of VGE and gender. In contrast, there were ample data about VGE from research in altitude chambers. Women produced less VGE and less Grade IV VGE compared to men under the same decompression dose, certainly when resting oxygen prebreathe (PB) was performed prior to ascent to altitude. Dual-cycle ergometry exercise during PB tends to reduce the differences in VGE between men and women. There was no compelling evidence that the risk of altitude DCS was different between men and women. However, a large number of DCS cases were associated with menses, and the use of BCP did seem to put women at a slightly greater risk than those that did not use BCP. There were substantial observations that women comprised a larger number of difficult cases that required complicated medical management.

  5. SLAP repair with arthroscopic decompression of spinoglenoid cyst

    PubMed Central

    Hashiguchi, Hiroshi; Iwashita, Satoshi; Ohkubo, Atsushi; Takai, Shinro

    2016-01-01

    Introduction: A spinoglenoid cyst with suprascapular nerve disorders is highly associated with superior labrum anterior posterior (SLAP) lesion. Conservative or surgical treatment is applied to relieve pain and neurological symptoms. The purpose of this study was to evaluate clinical outcomes of patients treated by arthroscopic surgery for SLAP lesion with a spinoglenoid cyst. Methods: The subjects of this study were six patients with SLAP lesion with a spinoglenoid cyst who underwent arthroscopic surgery. There was one female and five males with a mean age of 48.5 years. SLAP lesion was found in all the patients at arthroscopy. A small tear of the rotator cuff was found in the two patients. The SLAP lesion was repaired using suture anchors, and the rotator cuff tears were repaired by suture-bridge fixation. The spinoglenoid cyst was decompressed through the torn labrum in three patients, and through the released superior to posterior portion of the capsule in the other three patients. Results: All patients showed excellent improvement in pain and muscle strength at the final follow-up examination. The mean Constant score was improved from 60.5 points preoperatively to 97.2 points postoperatively. The mean visual analog scale (VAS) score decreased from 4.5 on the day of the surgery to 2.5 within one week postoperatively. Postoperative MRI showed disappearance or reduction of the spinoglenoid cyst in four and two patients, respectively. There were no complications from the surgical intervention and in the postoperative period. Discussion: The patients treated by decompression through the released capsule obtained pain relief at an early period after the surgery. Arthroscopic treatment for a spinoglenoid cyst can provide a satisfactory clinical outcome. Arthroscopic decompression of a spinoglenoid cyst through the released capsule is recommended for a safe and reliable procedure for patients with suprascapular nerve disorders. PMID:27163090

  6. [Aseptic bone flap osteonecrosis following cranioplasty after decompressive cranietomy].

    PubMed

    Smoll, Nicolas R; Stienen, Martin N; Schaller, Karl; Gautschi, Oliver P

    2013-06-19

    This case report discusses a case of aseptic osteonecrosis in a cranioplasty bone flap after decompressive craniectomy, which is a known, but rare complication after autologous cranioplasty. We suggest that the pathophysiology of cranial bone flap necrosis may have a similar pathophysiology to free flap necrosis/failure. The key suggested problem causing the osteonecrosis is vessel thrombosis within the smaller vessels of the bone flap due to the prothrombotic effects of the factors released during drilling of the bone flap. Suspicious local findings like wound dehiscence or fluid leakage should lead to a head computed tomography in order to discuss a prophylactic artificial second cranioplasty if necessary. PMID:23773942

  7. Ischiofemoral Space Decompression Through Posterolateral Approach: Cutting Block Technique

    PubMed Central

    Howse, Elizabeth A.; Mannava, Sandeep; Tamam, Cüneyt; Martin, Hal D.; Bredella, Miriam A.; Stubbs, Allston J.

    2014-01-01

    Ischiofemoral space impingement has become an increasingly recognized extracapsular cause of atypical hip, deep gluteal, and groin pain that can be treated endoscopically. We present a minimally invasive posterolateral technique that preserves the attachment of the iliopsoas tendon and quadratus femoris insertion while decompressing the ischiofemoral space by resecting the lesser trochanter. Furthermore, we present tips to perform this technique in a manner that minimizes the potential for damage to the sciatic nerve. This technique also allows the surgeon to treat concurrent hip pathology arthroscopically. PMID:25685670

  8. Surgical decompression for notalgia paresthetica: a case report.

    PubMed

    Williams, Eric H; Rosson, Gedge D; Elsamanoudi, Ibrahim; Dellon, A Lee

    2010-01-01

    Notalgia paresthetica is a rare nerve compression. From the Greek word noton, meaning "back," and algia, meaning "pain," "notalgia paresthetica" implies that symptoms of burning pain, itching, and/or numbness in the localized region between the spinous processes of T2 through T6 and the medial border of the scapula constitute a nerve compression syndrome. The compressed nerve is the dorsal branch of the spinal nerve. It is compressed by the paraspinous muscles and fascia against the transverse process of these spinal segments. This is the first report of symptomatic relief by decompression of this nerve. PMID:19790177

  9. Outcome Measures of an Intracanal, Endoscopic Transforaminal Decompression Technique: Initial Findings from the MIS Prospective Registry

    PubMed Central

    Sclafani, Joseph A.; Raiszadeh, Kamshad; Laich, Dan; Shen, Jian; Bennett, Matthew; Blok, Robert; Liang, Kevin

    2015-01-01

    Background Minimally invasive transforaminal endoscopic procedures can achieve spinal decompression through either direct or indirect techniques. Subtle variations in trajectory of the surgical corridor can dictate access to the pathologic tissue. Two general strategies exist: the intradiscal “inside-out” technique and the extradiscal, intracanal (IC) technique. The IC technique utilizes a more lateral transforaminal approach than the intradiscal technique, which allows for a more direct decompression of the spinal canal. Objective This study is an assessment of IC patient outcome data obtained through analysis of a previously validated MIS Prospective Registry. Methods Post-hoc analysis was performed on the MIS Prospective Registry database containing 1032 patients. A subgroup of patients treated with the endoscopic IC technique was identified. Patient outcome measures after treatment of symptomatic disk herniation and neuroforaminal stenosis were evaluated. Results A total of 86 IC patients were analyzed. Overall, there was significant improvement in employment and walking tolerance as soon as 6 weeks post-op as well as significant one year VAS and ODI score improvement. Subanalysis of IC patients with two distinct primary diagnoses was performed. Group IC-1 (disc herniation) showed improvement in ODI and VAS back and leg outcomes at 1 year post-op. Group IC-2 (foraminal stenosis) showed VAS back and leg score improvement at one year post-op but did not demonstrate significant improvement in overall ODI outcome at any time point. The one year re-operation rate was 2% (1/40) for group IC-1 and 28% (5/18) for group IC-2. Conclusions The initial results of the MIS Registry IC subgroup show a significant clinical improvement when the technique is employed to treat patients with lumbar disc herniation. The treatment of foraminal stenosis can lead to improved short-term clinical outcome but is associated with a high re-operation rate at 1 year post-op. PMID

  10. Cranioplasty Results after Application of Anti-adhesive Films (OrthoWrap™) in Traumatic Decompressive Craniectomy

    PubMed Central

    Khalili, Hosseinali; Omidvar, Aydin; Ghaffarpasand, Fariborz; Yadollahikhales, Golnaz

    2016-01-01

    Objective: To determine the effects of application of anti-adhesive films (OrthoWrap™) in traumatic decompressive craniectomy on prevention of adhesion formation and facilitation of subsequent cranioplasty. Methods: This was a retrospective cohort study being performed in ShahidRajaei hospital (Shiraz Level I trauma center) during a 12-month period (from March 2012 to April 2013) including 93 patients undergoing traumatic decompressivecraniectomy.Patients who received OrthoWrap™ during the initial craniectomy (n=44) were compared to those who did not (n=49). Two study groups were matched regarding the baseline characteristics. The perioperative indices including the surgical time, amount of bleeding, transfusion and 6-month Glasgow Outcome Scale (GOS) were compared between two study groups. Results: There was no significant difference between two study groups regarding the baseline characteristics. We found that the cranioplasty duration (113.3±33.2 vs. 146.9±34.9 minutes; p<0.001) and amount of intraoperative bleeding (182.1±98.3 vs. 270.6±77.6 mL; p=0.043) was significantly lower in those who had OrthoWrap™ compared to control group. The final GCS (p=0.052) as well as GOSE (p=0.653) was comparable between groups. The infection rate was comparable between two study groups (p=0.263). Conclusion: Application of OrthoWrap™ during decompressive craniectomy in those with severe traumatic brain injury is associated with shorter duration of operation and less intraoperative bleeding in subsequent cranioplasty. Infection rate and neurologic outcome was comparable between study groups. PMID:27162923

  11. Relationship between right-to-left shunts and cutaneous decompression illness.

    PubMed

    Wilmshurst, P T; Pearson, M J; Walsh, K P; Morrison, W L; Bryson, P

    2001-05-01

    The presence of a large right-to-left shunt is associated with neurological decompression illness after non-provocative dives, as a result of paradoxical gas embolism. A small number of observations suggest that cutaneous decompression illness is also associated with a right-to-left shunt, although an embolic aetiology of a diffuse rash is more difficult to explain. We performed a retrospective case--control comparison of the prevalence and sizes of right-to-left shunts determined by contrast echocardiography performed blind to history in 60 divers and one caisson worker with a history of cutaneous decompression illness, and 123 historical control divers. We found that 47 (77.0%) of the 61 cases with cutaneous decompression illness had a shunt, compared with 34 (27.6%) of 123 control divers (P<0.001). The size of the shunts in the divers with cutaneous decompression illness was significantly greater than in the controls. Thus 30 (49.2%) of the 61 cases with cutaneous decompression illness had a large shunt at rest, compared with six (4.9%) of the 123 controls (P<0.001). During closure procedures in 17 divers who had cutaneous decompression illness, the mean diameter of the foramen ovale was 10.9 mm. Cutaneous decompression illness occurred after dives that were provocative or deep in subjects without shunts, but after shallower and non-provocative dives in those with shunts. The latter individuals are at increased risk of neurological decompression illness. We conclude that cutaneous decompression illness has two pathophysiological mechanisms. It is usually associated with a large right-to-left shunt, when the mechanism is likely to be paradoxical gas embolism with peripheral amplification when bubble emboli invade tissues supersaturated with nitrogen. Cutaneous decompression illness can also occur in individuals without a shunt. In these subjects, the mechanism might be bubble emboli passing through an 'overloaded' lung filter or autochthonous bubble formation

  12. Improving extreme value statistics.

    PubMed

    Shekhawat, Ashivni

    2014-11-01

    The rate of convergence in extreme value statistics is nonuniversal and can be arbitrarily slow. Further, the relative error can be unbounded in the tail of the approximation, leading to difficulty in extrapolating the extreme value fit beyond the available data. We introduce the T method, and show that by using simple nonlinear transformations the extreme value approximation can be rendered rapidly convergent in the bulk, and asymptotic in the tail, thus fixing both issues. The transformations are often parametrized by just one parameter, which can be estimated numerically. The classical extreme value method is shown to be a special case of the proposed method. We demonstrate that vastly improved results can be obtained with almost no extra cost. PMID:25493780

  13. Probabilistic Assessment of Hypobaric Decompression Sickness Treatment Success

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Abercromby, Andrew F. J.; Dervay, Joseph P.; Feiveson, Alan H.; Gernhardt, Michael L.; Norcross, Jason R.; Ploutz-Snyder, Robert; Wessel, James H., III

    2014-01-01

    The Hypobaric Decompression Sickness (DCS) Treatment Model links a decrease in computed bubble volume from increased pressure (DeltaP), increased oxygen (O2) partial pressure, and passage of time during treatment to the probability of symptom resolution [P(symptom resolution)]. The decrease in offending volume is realized in 2 stages: a) during compression via Boyle's Law and b) during subsequent dissolution of the gas phase via the O2 window. We established an empirical model for the P(symptom resolution) while accounting for multiple symptoms within subjects. The data consisted of 154 cases of hypobaric DCS symptoms along with ancillary information from tests on 56 men and 18 women. Our best estimated model is P(symptom resolution) = 1 / (1+exp(-(ln(Delta P) - 1.510 + 0.795×AMB - 0.00308×Ts) / 0.478)), where (DeltaP) is pressure difference (psid), AMB = 1 if ambulation took place during part of the altitude exposure, otherwise AMB = 0; and where Ts is the elapsed time in mins from start of the altitude exposure to recognition of a DCS symptom. To apply this model in future scenarios, values of DeltaP as inputs to the model would be calculated from the Tissue Bubble Dynamics Model based on the effective treatment pressure: (DeltaP) = P2 - P1 | = P1×V1/V2 - P1, where V1 is the computed volume of a spherical bubble in a unit volume of tissue at low pressure P1 and V2 is computed volume after a change to a higher pressure P2. If 100% ground level O2 (GLO) was breathed in place of air, then V2 continues to decrease through time at P2 at a faster rate. This calculated value of (DeltaP then represents the effective treatment pressure at any point in time. Simulation of a "pain-only" symptom at 203 min into an ambulatory extravehicular activity (EVA) at 4.3 psia on Mars resulted in a P(symptom resolution) of 0.49 (0.36 to 0.62 95% confidence intervals) on immediate return to 8.2 psia in the Multi-Mission Space Exploration Vehicle. The P(symptom resolution) increased

  14. Extreme Physics

    NASA Astrophysics Data System (ADS)

    Colvin, Jeff; Larsen, Jon

    2013-11-01

    Acknowledgements; 1. Extreme environments: what, where, how; 2. Properties of dense and classical plasmas; 3. Laser energy absorption in matter; 4. Hydrodynamic motion; 5. Shocks; 6. Equation of state; 7. Ionization; 8. Thermal energy transport; 9. Radiation energy transport; 10. Magnetohydrodynamics; 11. Considerations for constructing radiation-hydrodynamics computer codes; 12. Numerical simulations; Appendix: units and constants, glossary of symbols; References; Bibliography; Index.

  15. Two Cases of Klippel-Feil Syndrome with Cervical Myelopathy Successfully Treated by Simple Decompression without Fixation.

    PubMed

    Kim, Jin Bum; Park, Seung Won; Lee, Young Seok; Nam, Taek Kyun; Park, Yong Sook; Kim, Young Baeg

    2015-09-01

    Klippel-Feil syndrome (KFS) is a congenital developmental disorder of cervical spine, showing short neck with restricted neck motion, low hairline, and high thoracic cage due to multilevel cervical fusion. Radiculopathy or myelopathy can be accompanied. There were 2 patients who were diagnosed as KFS with exhibited radiological and physical characteristics. Both patients had stenosis and cord compression at C1 level due to anterior displacement of C1 posterior arch secondary to kyphotic deformity of upper cervical spine, which has been usually indicative to craniocervical fixation. One patient was referred due to quadriparesis detected after surgery for aortic arch aneurysmal dilatation. The other patient was referred to us due to paraparesis and radiating pain in all extremities developed during gynecological examinations. Decompressive C1 laminectomy was done for one patient and additional suboccipital craniectomy for the other. No craniocervical fixation was done because there was no spinal instability. Motor power improved immediately after the operation in both patients. Motor functions and spinal stability were well preserved in both patients for 2 years. In KFS patients with myelopathy at the C1 level without C1-2 instability, a favorable outcome could be achieved by a simple decompression without spinal fixation. PMID:26512291

  16. Two Cases of Klippel-Feil Syndrome with Cervical Myelopathy Successfully Treated by Simple Decompression without Fixation

    PubMed Central

    Kim, Jin Bum; Lee, Young Seok; Nam, Taek Kyun; Park, Yong Sook; Kim, Young Baeg

    2015-01-01

    Klippel-Feil syndrome (KFS) is a congenital developmental disorder of cervical spine, showing short neck with restricted neck motion, low hairline, and high thoracic cage due to multilevel cervical fusion. Radiculopathy or myelopathy can be accompanied. There were 2 patients who were diagnosed as KFS with exhibited radiological and physical characteristics. Both patients had stenosis and cord compression at C1 level due to anterior displacement of C1 posterior arch secondary to kyphotic deformity of upper cervical spine, which has been usually indicative to craniocervical fixation. One patient was referred due to quadriparesis detected after surgery for aortic arch aneurysmal dilatation. The other patient was referred to us due to paraparesis and radiating pain in all extremities developed during gynecological examinations. Decompressive C1 laminectomy was done for one patient and additional suboccipital craniectomy for the other. No craniocervical fixation was done because there was no spinal instability. Motor power improved immediately after the operation in both patients. Motor functions and spinal stability were well preserved in both patients for 2 years. In KFS patients with myelopathy at the C1 level without C1-2 instability, a favorable outcome could be achieved by a simple decompression without spinal fixation. PMID:26512291

  17. Evidence and clinical outcomes of adult soft tissue sarcomas of the extremities treated with adjuvant high-dose-rate brachytherapy – a literature review

    PubMed Central

    2014-01-01

    The treatment strategies for adult soft tissue sarcomas of the extremities place an emphasis on local control, maintenance of limb function, and quality of life. Surgery is the mainstay of treatment for soft tissue sarcomas. Radiotherapy and chemotherapy are also both important treatments used in these patients to optimize the outcomes of limb sparing surgery. Compared to external beam radiation therapy, brachytherapy has the advantage of delivering a concentrated dose to the tumor, whilst sparing the normal tissues. Consequently, early and late complications such as bone fractures and subcutaneous fibrosis are potentially avoided by using brachytherapy. The evidence and clinical outcomes of HDR brachytherapy in soft tissue sarcomas of the extremities are described in this paper by means of a literature review. PMID:25337137

  18. Correlation between decompression sickness and circulating bubbles in 232 divers.

    PubMed

    Gardette, B

    1979-03-01

    Doppler monitoring examinations were carried out during 67 simulated helium-oxygen dives in the pressure chambers of the Centre d'Etudes Hyperbares (CEH) COMEX Marseille, and involved a total of 232 COMEX professional divers. Three to five detections were done in each 24-h period, each consisting of an observation at rest and an observation after deep knee bends. Recordings of the Doppler signals were subsequently analyzed by experienced listeners and graded according to the system described by Spencer and Johanson (1974). The two vestibular decompression accidents in this series were associated with bubble scores of grade 3 at rest; one occurred during the rapid initial phase of a bounce dive decompression and the other after return to the storage depth after an excursion dive. Twenty-five cases of muscular or joint pains were observed. A higher incidence of this type of problem was found with higher bubble grades in general, although it was not possible to predict pain. PMID:462655

  19. A very high speed lossless compression/decompression chip set

    NASA Technical Reports Server (NTRS)

    Venbrux, Jack; Liu, Norley; Liu, Kathy; Vincent, Peter; Merrell, Randy

    1991-01-01

    A chip is described that will perform lossless compression and decompression using the Rice Algorithm. The chip set is designed to compress and decompress source data in real time for many applications. The encoder is designed to code at 20 M samples/second at MIL specifications. That corresponds to 280 Mbits/second at maximum quantization or approximately 500 Mbits/second under nominal conditions. The decoder is designed to decode at 10 M samples/second at industrial specifications. A wide range of quantization levels is allowed (4...14 bits) and both nearest neighbor prediction and external prediction are supported. When the pre and post processors are bypassed, the chip set performs high speed entropy coding and decoding. This frees the chip set from being tied to one modeling technique or specific application. Both the encoder and decoder are being fabricated in a 1.0 micron CMOS process that has been tested to survive 1 megarad of total radiation dosage. The CMOS chips are small, only 5 mm on a side, and both are estimated to consume less than 1/4 of a Watt of power while operating at maximum frequency.

  20. Decompression syndrome (Caisson disease) in an Indian diver

    PubMed Central

    Phatak, Uday A.; David, Eric J.; Kulkarni, Pravin M.

    2010-01-01

    Acute decompression syndrome (Caisson’s disease) is an acute neurological emergency in divers. It is caused due to release of nitrogen gas bubbles that impinge the blood vessels of the spinal cord and brain and result in severe neurodeficit. There are very few case reports in Indian literature. There are multiple factors in the pathogenesis of Acute decompression syndrome (Caisson’s disease) such as health problems in divers (respiratory problems or congenital heart diseases like atrial septal defect, patent ductus arteriosus etc), speed of ascent from the depth and habits like smoking that render divers susceptible for such neurological emergency. Usually, immediate diagnosis of such a condition with MRI is not possible in hospitals in the Coastal border. Even though, MRI is performed, it has very low specificity and sensitivity. Facilities like hyperbaric oxygen treatment are virtually non-existent in these hospitals. Therefore, proper education of the divers and appropriate preventive measures in professional or recreational divers is recommended. PMID:21085532

  1. [Central nervous system involvement in patients with decompression illness].

    PubMed

    Kohshi, Kiyotaka; Katoh, Takahiko; Abe, Haruhiko; Wong, Robert M

    2003-05-01

    Dysbarism or decompression illness (DCI), a general term applied to all pathological changes secondary to altered environmental pressure, has two forms decompression sickness (DCS) and arterial gas embolism (AGE) after pulmonary barotrauma. Cerebral and spinal disorders have been symptomatically categorized as AGE and DCS, respectively. Magnetic resonance images (MRIs) of divers with DCI showed multiple cerebral infarction in the terminal and border zones of the brain arteries. In addition, there were no differences between MRI findings for compressed air and breath-hold divers. Although the pathogenesis of the brain is not well understood, we propose that arterialized bubbles passing through the lungs and heart involved the brain. From the mechanisms of bubble formation, however, this disorder has been classified as DCS. We propose that there is a difference between clinical and mechanical diagnoses in the criteria of brain DCI. In contrast to brain injury, the spinal cord is involved only in compressed air divers, and is caused by disturbed venous circulation due to bubbles in the epidural space. The best approach to prevent diving accidents is to make known the problems for professional and amateur divers. PMID:12833851

  2. Neuroprotective role of the TREK-1 channel in decompression sickness.

    PubMed

    Vallee, Nicolas; Meckler, Cédric; Risso, Jean-Jacques; Blatteau, Jean-Eric

    2012-04-01

    Nitrogen supersaturation and bubble formation can occur in the vascular system after diving, leading to death and nervous disorders from decompression sickness (DCS). Bubbles alter the vascular endothelium, activate platelets, and lead to focal ischemia with neurological damage mediated by the mechanosensitive TREK-1 neuronal potassium ion channel that sets pre- and postsynaptic resting membrane potentials. We report a neuroprotective effect associated with TREK-1. C57Bl6 mice were subjected to decompression from a simulated 90 msw dive. Of 143 mice that were wild type (WT) for TREK-1, 51.7% showed no DCS, 27.3% failed a grip test, and 21.0% died. Of 88 TREK-1 knockouts (KO), 26.1% showed no DCS, 42.0% failed a grip test, and 31.8% died. Mice that did not express TREK-1 had lower DCS resistance and were more likely to develop neurological symptoms. We conclude that the TREK-1 potassium channel was neuroprotective for DCS. PMID:22323654

  3. 2014 Decompression Sickness/Extravehicular Activity Risks Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan

    2015-01-01

    The 2014 Decompression Sickness (DCS)/Extravehicular Activity (EVA) Risks Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on November 4 - 5, 2014. The SRP reviewed the updated Evidence Reports for The Risk of Decompression Sickness (from here on referred to as the 2014 DCS Evidence Report) and the Risk of Injury and Compromised Performance due to EVA Operations (from here on referred to as the 2014 EVA Evidence Report), as well as the Research Plans for these Risks. The SRP appreciated the time and effort that the DCS and EVA disciplines put into their review documents and presentations. The SRP felt that the 2014 DCS Evidence Report and the 2014 EVA Evidence Reports were very thorough and addressed the majority of the known DCS and EVA issues. The researchers at NASA Johnson Space Center (JSC) have the knowledge base to deal with the DCS and EVA issues. Overall, the SRP thinks the DCS and EVA research teams have compiled excellent reports which address the majority of the literature and background information.

  4. Bubble formation in crustaceans following decompression from hyperbaric gas exposures.

    PubMed

    McDonough, P M; Hemmingsen, E A

    1984-02-01

    In vivo bubble formation was studied in various crustaceans equilibrated with high gas pressures and rapidly decompressed to atmospheric pressure. The species varied widely in susceptibility to bubble formation, and adults were generally more susceptible than larval stages. Bubbles did not form in early brine shrimp larvae unless equilibration pressures of at least 175 atm argon or 350 atm helium were used; for adult brine shrimp, copepods, and the larvae of crabs and shrimps, 100-125 atm argon or 175-225 atm helium were required. In contrast, bubbles formed in the leg joints of megalopa and adult crabs following decompression from only 3-10 atm argon; stimulation of limb movements increased this bubble formation, whereas inhibition of movements decreased it. High hydrostatic compressions applied before gas equilibration or slow compressions did not affect bubble formation. We concluded that circulatory systems, musculature, and storage lipids do not necessarily render organisms susceptible to bubble formation and that bubbles do not generally originate as preformed nuclei. In some cases, tribonucleation appears to be the cause of the bubbles. PMID:6706762

  5. Simvastatin decreases incidence of decompression sickness in rats.

    PubMed

    Zhang, Kun; Wang, Dong; Xu, Jiajun; Li, Runping; Cai, Zhiyu; Liu, Kan; Zheng, Juan; Denoble, Petar J; Fang, Yiqun; Xu, Weigang

    2015-01-01

    Decompression sickness (DCS) is a specific diving injury which sometimes may be life-threatening. Previous studies suggested that simvastatin (SIM) can protect against pathological inflammation and tissue damage. This study aimed to investigate whether SIM pretreatment could exert its beneficial effects on DCS. SIM was administered orally to adult male Sprague-Dawley rats for two weeks (2 mg/kg/day), then rats were subjected to a simulated dive at 700 kPa air pressure for 100 minutes before rapid decompression. After 30 minutes of symptom observation, lung tissue and blood samples were collected for further analysis. Compared to the vehicle-control, SIM pretreatment significantly decreased the incidence of DCS and ameliorated all parameters of pulmonary injuries, including lung dry/wet weight ratio, bronchoalveolar lavage fluid protein concentration, lung tissue malondialdehyde level and morphology. Moreover, SIM pretreatment abolished increases in systemic and pulmonary inflammation by reducing tumor necrosis factor-α levels in blood plasma and lung tissue. The results indicate that SIM may offer a novel pharmacological protection against injuries in DCS rats by inhibiting inflammatory responses. Further study is needed to understand the exact mechanisms. PMID:26094286

  6. Case Descriptions and Observations About Cutis Marmorata From Hypobaric Decompressions

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Pilmanis, Andrew A.; Webb, James T.

    2002-01-01

    There is disagreement about the pathophysiology, classification, and treatment of cutis marmorata (CM), so there is disagreement about the disposition and medical status of a person that had CM. CM is rare, associated with stressful decompressions, and may be associated with serious signs and symptoms of decompression sickness (DCS). CM presents as purple or bluish-red skin mottling, often in the pectoral region, shoulders, chest, or upper abdomen. It is unethical to induce CM in humans so all information comes from retrospective analysis of case reports, or from animal models. A literature search, seven recent case reports from the Johnson Space Center and Brooks Air Force Base Hypobaric DCS Databases, interviews with DCS treatment experts, and responses to surveys provided the factual information used to arrive at our conclusions and recommendations. The "weight of evidence" indicates that CM is a local, not centrally mediated or systemic response to bubbles. It is unclear whether obstruction of arterial or venous blood flow is the primary insult since the lesion is reported under either condition. Any neurological or cardiovascular involvements are coincidental, developing along the same time course. The skin could be the source of the bubbles due to its mass, the associated layer of fat, and the variable nature of skin blood flow. CM should not be categorized as Type II DCS, should be included with other skin manifestations in a category called cutaneous DCS, and hyperbaric treatment is only needed if ground level oxygen is ineffective in the case of altitude-induced CM.

  7. Transesophageal Echocardiographic Study of Decompression-Induced Venous Gas Emboli

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Morris, W. P.

    1995-01-01

    Transesophageal echo-cardiography was used to evaluate venous bubbles produced in nine anesthetized dogs following decompression from 2.84 bar after 120 min at pressure. In five dogs a pulsed Doppler cuff probe was placed around the inferior vena cava for bubble grade determination. The transesophageal echo images demonstrated several novel or less defined events. In each case where the pulmonary artery was clearly visualized, the venous bubbles were seen to oscillate back and forth several times, bringing into question the effect of coincidental counting in routine bubble grade analysis using precordial Doppler. A second finding was that in all cases, extensive bubbling occurred in the portal veins with complete extraction by the liver sinusoids, with one exception where a portal-to-hepatic venous anastomosis was observed. Compression of the bowel released copious numbers of bubbles into the portal veins, sometimes more than were released into the inferior vena cava. Finally, large masses of foam were routinely observed in the non-dependent regions of the inferior vena cava that not only delayed the appearance of bubbles in the pulmonary artery but also allowed additional opportunity for further reaction with blood products and for coalescence to occur before reaching the pulmonary microcirculation. These novel observations are discussed in relation to the decompression process.

  8. Recurrent subdural hygromas after foramen magnum decompression for Chiari Type I malformation.

    PubMed

    Pereira, Erlick A C; Steele, Louise F; Magdum, Shailendra A

    2014-06-01

    A paediatric case of foramen magnum decompression for Chiari Type I malformation complicated by recurrent subdural hygromas (SH) and raised intracranial pressure without ventriculomegaly is described. SH pathogenesis is discussed, with consideration given to arachnoid fenestration. We summarise possibilities for treatment and avoidance of this unusual consequence of foramen magnum decompression. PMID:23952134

  9. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The... within any 12-hour period. The limit is the maximum bottom time in minutes that a diver can spend at...

  10. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The... within any 12-hour period. The limit is the maximum bottom time in minutes that a diver can spend at...

  11. Investigating Disequilibrium Degassing of H2O and CO2 in Rhyolitic Melts: New Insights from Cold-Seal Decompression Experiments

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.; Wallace, P. J.

    2012-12-01

    Magmatic degassing, or the diffusion of volatiles once dissolved in the melt into a vapor phase, is a critical process that influences eruption explosivity and is in turn affected by magma ascent rate. Experimental research has demonstrated that rapid magma decompression rates can result in delayed, disequilibrium degassing of H2O when diffusion of H2O to bubbles is slow compared to the decompression rate (e.g., Mangan and Sisson, 2000). Although disequilibrium degassing has been documented through previous experimental work, much of the previous work has focused on single volatile (H2O-only) systems, with an emphasis on the effect of rapid ascent on bubble nucleation. Our research investigates disequilibrium degassing of multiple volatile components (CO2 and H2O) and the effects on water speciation (molecular H2O and hydroxyl) during decompression using cold-seal decompression experiments. Our experiments are on rhyolitic melts, though the results have implications for other magma types. The starting material is a powdered sample of Bishop Tuff high-silica rhyolite, to which 6 wt% H2O has been added along with varying amounts of CO2. Samples are held at high pressure and temperature (200 MPa and ~780 C) for at least 24 hours to ensure homogenization above the liquidus. Some samples are quenched after this time period (solubility experiments), and will serve as comparison for the decompression runs. In other experiments, after homogenization the pressure will be decreased at a range of decompression rates that correspond to rates expected for effusive, dome-forming eruptions to highly explosive eruptions, where disequilibrium degassing is most likely to occur. The quenched end-products of the experiments will be analyzed using Fourier Transform Infrared (FTIR) spectroscopy, allowing us to constrain not only the total H2O and CO2 contents, but also H2O speciation (H2O and OH-). In decompression experiments, glasses will be analyzed in transects with distance from

  12. The effect of extended O2 prebreathing on altitude decompression sickness and venous gas bubbles

    NASA Technical Reports Server (NTRS)

    Waligora, James M.; Horrigan, David J.; Conkin, Johnny

    1987-01-01

    The purpose of this study was to determine the effect of extended O2 prebreathing on symptom and bubble incidence during decompressions simulating extravehicular activity. The 38 subjects breathed O2 for a 6-hr period prior to decompression to 4.3 psi. The subjects performed upper body exercises for 6 hr. Eight subjects were exposed to the same protocol after an 8-hr prebreathe. Venous bubbles were detected in 18 of 38 subjects decompressed after the 6-hr prebreathe. Four of these subjects reported symptoms of altitude decompression sickness. No symptoms or bubbles were detected in the eight subjects who had prebreathed 8 hr. The incidence of symptoms and bubbles, when combined with prior data on 3.5- and 4.0-hr prebreathes, showed an inverse correlation to prebreathing time. The incidence of symptoms was higher than has been reported for subjects exposed to decompression of shorter duration with less activity.

  13. Predictors of outcome after decompressive lumbar surgery and instrumented posterolateral fusion.

    PubMed

    Cobo Soriano, Javier; Sendino Revuelta, Marcos; Fabregate Fuente, Martín; Cimarra Díaz, Ignacio; Martínez Ureña, Paloma; Deglané Meneses, Roberto

    2010-11-01

    There has been no agreement among different authors on guidelines to specify the situations in which arthrodesis is justified in terms of results, risks and complications. The aim of this study was to identify preoperative predictors of outcome after decompressive lumbar surgery and instrumented posterolateral fusion. A prospective observational study design was performed on 203 consecutive patients. Potential preoperative predictors of outcome included sociodemographic factors as well as variables pertaining to the preoperative clinical situation, diagnosis, expectations and surgery. Separate multiple linear regression models were used to assess the association between selected predictors and outcome variables, defined as the improvement after 1 year on the visual analog scale (VAS) for back pain, VAS for leg pain, physical component scores (PCS) of SF-36 and Oswestry disability index (ODI). Follow-up was available for 184 patients (90.6%). Patients with higher educational level and optimistic preoperative expectations had a more favourable postoperative leg pain (VAS) and ODI. Smokers had less leg pain relief. Patients with better mental component score (emotional health) had greater ODI improvement. Less preoperative walking capacity predicted more leg pain relief. Patients with disc herniation had greater relief from back pain and more PCS and ODI improvement. More severe lumbar pain was predictive of less improvement on ODI and PCS. Age, sex, body mass index, analgesic use, surgeon, self-rated health, the number of decompressed levels and the length of fusion had no association with outcome. This study concludes that a higher educational level, optimistic expectations for improvement, the diagnosis of "disc herniation", less walking capacity and good emotional health may significantly improve clinical outcome. Smoking and more severe lumbar pain are predictors of worse results. PMID:20135333

  14. Predictors of outcome after decompressive lumbar surgery and instrumented posterolateral fusion

    PubMed Central

    Sendino Revuelta, Marcos; Cimarra Díaz, Ignacio; Martínez Ureña, Paloma; Deglané Meneses, Roberto

    2010-01-01

    There has been no agreement among different authors on guidelines to specify the situations in which arthrodesis is justified in terms of results, risks and complications. The aim of this study was to identify preoperative predictors of outcome after decompressive lumbar surgery and instrumented posterolateral fusion. A prospective observational study design was performed on 203 consecutive patients. Potential preoperative predictors of outcome included sociodemographic factors as well as variables pertaining to the preoperative clinical situation, diagnosis, expectations and surgery. Separate multiple linear regression models were used to assess the association between selected predictors and outcome variables, defined as the improvement after 1 year on the visual analog scale (VAS) for back pain, VAS for leg pain, physical component scores (PCS) of SF-36 and Oswestry disability index (ODI). Follow-up was available for 184 patients (90.6%). Patients with higher educational level and optimistic preoperative expectations had a more favourable postoperative leg pain (VAS) and ODI. Smokers had less leg pain relief. Patients with better mental component score (emotional health) had greater ODI improvement. Less preoperative walking capacity predicted more leg pain relief. Patients with disc herniation had greater relief from back pain and more PCS and ODI improvement. More severe lumbar pain was predictive of less improvement on ODI and PCS. Age, sex, body mass index, analgesic use, surgeon, self-rated health, the number of decompressed levels and the length of fusion had no association with outcome. This study concludes that a higher educational level, optimistic expectations for improvement, the diagnosis of “disc herniation”, less walking capacity and good emotional health may significantly improve clinical outcome. Smoking and more severe lumbar pain are predictors of worse results. PMID:20135333

  15. Clinical and Radiological Results of Microsurgical Posterior Lumbar Interbody Fusion and Decompression without Posterior Instrumentation for Lateral Recess Stenosis

    PubMed Central

    Şişman, Lokman; Türkmen, Faik; Efe, Duran; Pekince, Oğuzhan; Göncü, Recep Gani; Sever, Cem

    2015-01-01

    Study Design A single-center, retrospective patient review of clinical and radiological outcomes of microsurgical posterior lumbar interbody fusion and decompression, without posterior instrumentation, for the treatment of lateral recess stenosis. Purpose This study documented the clinical and radiological results of microsurgical posterior lumbar interbody fusion and decompression of the lateral recess using interbody cages without posterior instrumentation for the treatment of lateral recess stenosis. Overview of Literature Although microsurgery has some advantages, various complications have been reported following microsurgical decompression, including cage migration, pseudoarthrosis, neurologic deficits, and persistent pain. Methods A total of 34 patients (13 men, 21 women), with a mean age of 56.65±9.1 years (range, 40-77 years) confirmed spinal stability, and preoperative radiological findings of lateral recess stenosis, were included in the study. Interbody polyetheretherketone cages and auto grafts were used in all patients. Posterior instrumentation was not used because of limited resection of the posterior lumbar structures. Preoperative and postoperative radiographs, computed tomography scans, and magnetic resonance imaging were assessed and compared to images taken at the final follow-up. Functional recovery was also evaluated according to the Macnab criteria at the final follow-up. Results The average follow-up time was 35.05±8.65 months (range, 24-46 months). The clinical results, operative time, intraoperative blood loss, and duration of hospital stay were similar to previously published results; the fusion rate (85.2%) was decreased and the migration rate (5.8%) was increased, compared with prior reports. Conclusions Although microsurgery has some advantages, migration and pseudoarthrosis remain challenges to achieving adequate lumbar interbody fusion. PMID:26435789

  16. Mid- to long-term outcomes of posterior decompression with instrumented fusion for thoracic ossification of the posterior longitudinal ligament.

    PubMed

    Koda, Masao; Furuya, Takeo; Okawa, Akihiko; Inada, Taigo; Kamiya, Koshiro; Ota, Mitsutoshi; Maki, Satoshi; Takahashi, Kazuhisa; Yamazaki, Masashi; Aramomi, Masaaki; Ikeda, Osamu; Mannoji, Chikato

    2016-05-01

    Posterior decompression with instrumented fusion (PDF) surgery has been previously reported as a relatively safe surgical procedure for any type of thoracic ossification of the longitudinal ligament (OPLL). However, mid- to long-term outcomes are still unclear. The aim of the present study was to elucidate the mid- to long-term clinical outcome of PDF surgery for thoracic OPLL patients. The present study included 20 patients who had undergone PDF for thoracic OPLL and were followed for at least 5years. Increment change and recovery rate of the Japanese Orthopaedic Association (JOA) score were assessed. Revision surgery during the follow-up period was also recorded. Average JOA scores were 3.5 preoperatively and 7.1 at final follow-up. The average improvement in JOA score was 3.8 points and the average recovery rate was 47.0%. The JOA score showed gradual increase after surgery, and took 9months to reach peak recovery. As for neurological complications, two patients suffered postoperative paralysis, but both recovered without intervention. Six revision surgeries in four patients were related to OPLL. Additional anterior thoracic decompression for remaining ossification at the same level of PDF surgery was performed in one patient. Decompression surgery for deterioration of symptoms of pre-existing cervical OPLL was performed in three patients. One patient had undergone lumbar and cervical PDF surgery for de novo ossification foci of the lumbar and cervical spine. PDF surgery for thoracic OPLL is thus considered a relatively safe and stable surgical procedure considering the mid- to long-term outcomes. PMID:26794690

  17. Delayed, disequilibrium degassing in rhyolite magma: Decompression experiments and implications for explosive volcanism

    USGS Publications Warehouse

    Mangan, M.; Sisson, T.

    2000-01-01

    Recent numerical models and analog shock tube experiments show that disequilibrium degassing during magma ascent may lead to violent vesiculation very near the surface. In this study a series of decompression experiments using crystal-free, rhyolite melt were conducted to examine the development of large supersaturations due to delayed, homogenous (spontaneous) bubble nucleation. Melts were saturated at 900??C and 200 MPa with either 5.2 wt% dissolved H2O, or with 4.2 wt% H2O and 640 ppm CO2, and isothermally decompressed at linear rates of either 0.003, 0.025, or 8.5 MPa/s to final pressures between 25 and 175 MPa. Additional isobaric saturation experiments (900??C, 200-25 MPa) using pure H2O or mixed H2O-CO2 fluids establish reference equilibrium solubility curves/values. Homogenous nucleation is triggered in both H2O-only and H2O-CO2 experiments once the supersaturation pressure (??Pss) reaches ?? 120-150 MPa and the melt contains ?? two times its equilibrium water contents. Bubble number density and nucleation rate depend on the supersaturation pressure, with values on the order of 102/cm3 and < 1/cm3/s for ??Pss~120 MPa; 106/cm3 and 103-105/cm3/s for ??Pss??~130-150 MPa; and 107/cm3 and 106/cm3/s for ??Pss??160-175 MPa. Nucleation rates are consistent with classical nucleation theory, and infer an activation energy for nucleation of 1.5 x 10-18 J/nucleus, a critical bubble radius of 2 x 10-9 m, and an effective surface tension for rhyolite at 5.2 wt% H2O and 900??C of 0.10-0.11 N/m. The long nucleation delay limits the time available for subsequent diffusion such that disequilibrium dissolved H2O and CO2 contents persist to the end of our runs. The disequilibrium degassing paths inferred from our experiments contrast markedly with the equilibrium or quasi-equilibrium paths found in other studies where bubble nucleation occurs heterogenously on crystals or other discontinuities in the melt at low ??Pss. Homogenous and heterogenous nucleation rates are

  18. Evidence-Based Approach to the Analysis of Serious Decompression Sickness with Application to EVA Astronauts

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny

    2001-01-01

    It is important to understand the risk of serious hypobaric decompression sickness (DCS) in order to develop procedures and treatment responses to mitigate the risk. Since it is not ethical to conduct prospective tests about serious DCS with humans, the necessary information was gathered from 73 published reports. We hypothesize that a 4-hr 100% oxygen (O2) prebreathe results in a very low risk of serious DCS, and test this through analysis. We evaluated 258 tests containing information from 79,366 exposures in attitude chambers. Serious DCS was documented in 918 men during the tests. Serious DCS are signs and symptoms broadly classified as Type II DCS. A risk function analysis with maximum likelihood optimization was performed to identify significant explanatory variables, and to create a predictive model for the probability of serious DCS [P(serious DCS)]. Useful variables were Tissue Ratio, the planned time spent at altitude (T(sub alt)), and whether or not repetitive exercise was performed at altitude. Tissue Ratio is P1N2/P2, where P1N2 is calculated nitrogen (N2) pressure in a compartment with a 180-min half-time for N2 pressure just before ascent, and P2 is ambient pressure after ascent. A prebreathe and decompression profile Shuttle astronauts use for extravehicular activity (EVA) includes a 4-hr prebreathe with 100% O2, an ascent to P2 = 4.3 lb per sq. in. absolute, and a T(sub alt) = 6 hr. The P(serious DCS) is: 0.0014 (0.00096 - 0.00196, 95% confidence interval) with exercise and 0.00025 (0.00016 - 0.00035) without exercise. Given 100 Shuttle EVAs to date and no report of serious DCS, the true risk is less than 0.03 with 95% confidence (Binomial Theorem). It is problematic to estimate the risk of serious DCS since it appears infrequently, even if the estimate is based on thousands of altitude chamber exposures. The true risk to astronauts may lie between the extremes of the confidence intervals (0.00016 - 0.00196) since the contribution of other factors

  19. The Survey of the Patient Received the Epiduroscopic Laser Neural Decompression

    PubMed Central

    Jo, Dae Hyun

    2013-01-01

    Background Neuroplasty using a Racz catheter or epiduroscope and percutaneous endoscopic laser discectomy are performed as treatment for chronic refractory low back and/or lower extremity pain, but they are limited in that they cannot completely remove the causing pathology. Lately, epiduroscopic laser neural decompression (ELND) has been receiving attention as an alternative treatment, but there are insufficient reports of results. Hence we aimed to investigate and report the data in our hospital. Methods Seventy-seven patients were selected who had received ELND via the anterior and posterior epidural approach through the pain clinic in our hospital from March 2011 to July 2012. Their medical records including age, diagnosis, epiduroscopic findings and degree of symptom relief were investigated. The degree of symptom relief following the procedure was categorized into 5 stages of very good (5), good (4), no change (3), bad (2), and very bad (1) at 2 weeks and 1 month after the procedure. Results The subjects were 30 males and 47 females. Mean age was 54.6 for males and 59.6 for females, so the overall mean age was 58.1 years old, with the youngest being 23 and the oldest 88 years old. In epiduroscopic images of all patients, more than one situation of herniated disc, fibrous tissue and adhesion, or inflammation was observed. Sixty-seven patients (87.0%) showed symptom relief 2 weeks after the procedure and 63 patients (81.8%) showed relief after 1 month. Conclusions ELND is considered to be an effective treatment alternative for chronic refractory low back and/or lower extremity pain, including lumbar disc herniation, lumbar spinal stenosis, and failed back surgery syndrome which cannot be alleviated with existing non-invasive conservative treatment. PMID:23342204

  20. Failed needle decompression of bilateral spontaneous tension pneumothorax.

    PubMed

    Bach, P T; Sølling, C

    2015-07-01

    This case report presents a young male admitted with primary bilateral spontaneous tension pneumothorax and severe respiratory distress. This is an extremely rare condition. The patient was on the verge of hypoxic cardiac arrest and the attempted needle thoracocentesis was unsuccessful. Needle thoracocentesis in the midclavicular line of the second intercostal space is widely used and recommended as first-line treatment of tension pneumothorax. Reviewing the literature, the procedure is not based on solid evidence. It has high failure rates and potentially serious complications. Alternatives to this approach are perhaps more appropriate. Correctly done, needle thoracocentesis has its place in the presence of a diagnosed or suspected tension pneumothorax when no other options are available. If needle thoracocentesis is chosen, then insertion in the mid-anterior axillary line of the 3rd-5th intercostal space is an appropriate alternative site. Otherwise, lateral thoracostomy, with or without chest tube insertion, is a safe procedure with a high success rate. It should be considered as the first-line treatment of tension pneumothorax, particularly in the unstable patient. PMID:25900313

  1. Decompression of Neglected Compartment Syndrome of the Arm

    PubMed Central

    Fletcher, Matt DA

    2015-01-01

    Introduction: Compartment syndrome of the arm is rare, and delay in diagnosis or treatment can be devastating. A case is reported of compartment syndrome of the whole arm occurring in a remote location and arrival at hospital 15 hours after injury with good results despite delayed treatment. Case Report: A 26 year old male presented with a combined crush injury and compartment syndrome of the arm, with delay in presentation due to remote injury and delay in rescue. Late (>16 hours)fasciotomy was performed with retention of the upper arm, elbow and proximal forearm with good residual function. Conclusion: Despite significant delay in treatment of compartment syndrome of the arm, useful function and tissue can be preserved with adequate decompression. PMID:27299052

  2. Intravenous Fluid Therapy in Traumatic Brain Injury and Decompressive Craniectomy

    PubMed Central

    Alvis-Miranda, Hernando Raphael; Castellar-Leones, Sandra Milena; Moscote-Salazar, Luis Rafael

    2014-01-01

    The patient with head trauma is a challenge for the emergency physician and for the neurosurgeon. Currently traumatic brain injury constitutes a public health problem. Knowledge of the various supportive therapeutic strategies in the pre-hospital and pre-operative stages is essential for optimal care. The immediate rapid infusion of large volumes of crystalloids to restore blood volume and blood pressure is now the standard treatment of patients with combined traumatic brain injury (TBI) and hemorrhagic shock (HS). The fluid in patients with brain trauma and especially in patients with brain injur y is a critical issue. In this context we present a review of the literature about the history, physiology of current fluid preparations, and a discussion regarding the use of fluid therapy in traumatic brain injury and decompressive craniectomy. PMID:27162857

  3. Decompression of Odontogenic Cystic Lesions: Past, Present, and Future.

    PubMed

    Castro-Núñez, Jaime

    2016-01-01

    Tumors and cystic lesions of the jawbones have been described since the late 1600s and it took another 200 years for classification systems to appear in the medical, surgical, and dental literatures. In the late 1800s, Carl Partsch introduced cystostomy, a method by which the cyst is converted into a pouch by suturing its lining to the mucosa of the oral cavity. The purpose of this article is to analyze the history, present, and future of cystic conditions of the jaws and decompression, a modality of treatment that during the past few years has regained the attention of oral and maxillofacial surgeons and pathologists owing to its relative simplicity and effectiveness compared with other conservative options. PMID:26428611

  4. Management of a patient with pericardial decompression syndrome and HOCM.

    PubMed

    Fozing, Thierry; Zouri, Nayef; Adam, Oliver; Oezbek, Cem

    2016-01-01

    A 44-year-old man, with a history of arterial hypertension, was referred with increasing shortness of breath due to a large pericardial effusion and imminent tamponade. Emergency ultrasound-guided pericardiocentesis resulted in the rapid withdrawal of 2760 cc of serous fluid. 3 hours later, the patient developed acute pulmonary oedema, which was successfully treated. Hypertrophic obstructive cardiomyopathy was later diagnosed and malignancy was excluded as a cause of the effusion. Clinicians performing pericardiocentesis need to be aware of pericardial decompression syndrome (PDS), a rare but serious complication. Although the underlying mechanisms causing PDS are not fully understood, patients with high left ventricular (LV) filling pressures are at particular risk. In other words: diastolic dysfunction of the LV is a risk factor for the occurrence of PDS. PMID:27251601

  5. Bubble dissolution physics and the treatment of decompression sickness

    SciTech Connect

    Kunkle, T.D.; Beckman, E.L.

    1983-03-01

    The treatment of decompression sickness often involves both recompressing the victim and administering hyperbaric oxygen in the hope of more rapidly dissolving the bubbles which cause this malady. Although many hundreds of such treatments are conducted each year in the United States alone, the underlying physical principles governing the dissolution of such bubbles are not well understood and only empirically tested. In this paper, we present a mathematical theory of bubble dissolution that is verified by comparison with laboratory experiments. This theory suggests that the commonly employed treatment techniques would be only marginally effective, and that in many situations the bubbles that cause the disease cannot be adequately dissolved using existing techniques and facilities.

  6. The role of radiology in percutaneous laser disc decompression.

    PubMed

    Botsford, J A

    1995-06-01

    Diagnostic imaging has always played a key role in the evaluation of patients with suspected lumbar disc herniation. With the development of percutaneous laser disc decompression (PLDD), radiology is now equally important in its treatment. All physicians involved with the PLDD candidate must be familiar with the imaging techniques unique to this procedure to ensure a successful outcome. The following review is based on the cumulative experience gained in performing over 200 PLDD procedures. It discusses the function of diagnostic radiology in all facets of PLDD including patient selection, intraoperative imaging, postoperative evaluation, and analysis of complications. Fundamental radiologic concepts that apply to PLDD are explained and protocols suggested to optimize results and avoid complications. PMID:10150644

  7. Percutaneous laser disc decompression: an update--Spring 1992.

    PubMed

    Choy, D S; Michelsen, J; Getrajdman, G; Diwan, S

    1992-06-01

    Percutaneous laser disc decompression (PLDD) is being performed in multiple centers in the United States, Germany, Austria, France, and Switzerland with the Nd:YAG having the longest follow up at more than 75 months. The experience with this procedure, in both humans and animals, carried out over the past decade is presented along with a detailed discussion of the surgical procedure. Conditions that favor such surgery and contraindications to the procedure are also presented. There are a number of important advantages to PLDD that make it a procedure that merits continued investigation. Because PLDD is relatively noninvasive, it can be repeated. Because there is no cutting, there is no perispinal scar formation, with possible future pain secondary to entrapment of nerves by scar. Because of its effectiveness for treatment, the laser, in this application, should prove to be an important addition to the spinal surgeon's armamentarium. PMID:10147861

  8. Extreme Events

    NASA Astrophysics Data System (ADS)

    Nott, Jonathan

    2006-04-01

    The assessment of risks posed by natural hazards such as floods, droughts, earthquakes, tsunamis or cyclones, is often based on short-term historical records that may not reflect the full range or magnitude of events possible. As human populations grow, especially in hazard-prone areas, methods for accurately assessing natural hazard risks are becoming increasingly important. In Extreme Events Jonathan Nott describes the many methods used to reconstruct such hazards from natural long-term records. He demonstrates how long-term (multi-century to millennial) records are essential in gaining a realistic understanding of the variability of natural hazards, and how short-term historical records can often misrepresent the likely risks associated with natural hazards. This book will form a useful resource for students taking courses covering natural hazards and risk assessment. It will also be valuable for urban planners, policy makers and non-specialists as a guide to understanding and reconstructing long-term records of natural hazards. Explains mechanisms that cause extreme events and discusses their prehistoric records Describes how to reconstruct long-term records of natural hazards in order to make accurate risk assessments Demonstrates that natural hazards can follow cycles over time and do not occur randomly

  9. Effect of metabolic gases and water vapor, perfluorocarbon emulsions, and nitric oxide on tissue bubbles during decompression sickness.

    PubMed

    Randsøe, Thomas

    2016-05-01

    In aviation and diving, fast decrease in ambient pressure, such as during accidental loss of cabin pressure or when a diver decompresses too fast to sea level, may cause nitrogen (N2) bubble formation in blood and tissue resulting in decompression sickness (DCS). Conventional treatment of DCS is oxygen (O2) breathing combined with recompression.  However, bubble kinetic models suggest, that metabolic gases, i.e. O2 and carbon dioxide (CO2), and water vapor contribute significantly to DCS bubble volume and growth at hypobaric altitude exposures. Further, perfluorocarbon emulsions (PFC) and nitric oxide (NO) donors have, on an experimental basis, demonstrated therapeutic properties both as treatment and prophylactic intervention against DCS. The effect was ascribed to solubility of respiratory gases in PFC, plausible NO elicited nuclei demise and/or N2 washout through enhanced blood flow rate. Accordingly, by means of monitoring injected bubbles in exposed adipose tissue or measurements of spinal evoked potentials (SEPs) in anaesthetized rats, the aim of this study was to: 1) evaluate the contribution of metabolic gases and water vapor to bubble volume at different barometrical altitude exposures, 2) clarify the O2 contribution and N2 solubility from bubbles during administration of PFC at normo- and hypobaric conditions and, 3) test the effect of different NO donors on SEPs during DCS upon a hyperbaric air dive and, to study the influence of  NO on tissue bubbles at high altitude exposures. The results support the bubble kinetic models and indicate that metabolic gases and water vapor contribute significantly to bubble volume at 25 kPa (~10,376 m above sea level) and constitute a threshold for bubble stabilization or decay at the interval of 47-36 kPa (~6,036 and ~7,920 m above sea level). The effect of the metabolic gases and water vapor seemed to compromise the therapeutic properties of both PFC and NO at altitude, while PFC significantly increased bubble

  10. 2014 Decompression Sickness/Extravehicular Activity Risks Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan; Mahon, Richard; Klaus, David; Neuman, Tom; Pilmanis, Andrew; Regis, David

    2014-01-01

    The 2014 Decompression Sickness (DCS)/Extravehicular Activity (EVA) Risks Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on November 4 - 5, 2014. The SRP reviewed the Research Plans for The Risk of Decompression Sickness and the Risk of Injury and Compromised Performance due to EVA Operations, as well as the Evidence Reports for both of these Risks. The SRP found that the NASA DCS/EVA team did an excellent job of presenting their research plans. The SRP considers it critical that NASA proceeds with the high priority tasks identified in this report (DCS1, DCS3, DCS5). The highest priority is to determine the acceptable DCS and hypoxia risk associated with the planned human exploration beyond low Earth orbit. The risk of DCS is highly dependent upon the pressure within the exploration vehicle. If slightly more hypoxia is permitted then (even with the same percentage of oxygen) the pressure within the exploration vehicle can be lowered thus further mitigating the risk of DCS. The second highest priority is to test and validate the recommended 8.2psi/34% O2 atmosphere. Development of procedures and equipment for human exploration missions are very limited until the results of this testing are completed. The SRP also suggests that DCS7 be separated into two Gaps. Gap DCS7 should deal with DCS treatment while a new Gap should be created to deal with the long-term effects of DCS. The SRP also encourages NASA to increase collaboration with other organizations and pool resources where possible. The current NASA DCS/EVA team has the extensive expertise and a wealth of knowledge in this area. The SRP suggests that increased manpower for this team would be highly productive.

  11. The Mars Project: Avoiding Decompression Sickness on a Distant Planet

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny

    2000-01-01

    A cost-effective approach for Mars exploration is to use available resources, such as water and atmospheric gases. Nitrogen (N2) and argon (Ar) are available and could form the inert gas component of a habitat atmosphere at 8.0, 9.0, or 10.0 pounds per square inch (psia). The habitat and space suit are designed as an integrated system: a comfortable living environment about 85% of the time and a safe working environment about 15% of the time. A goal is to provide a system that permits unrestricted exploration of Mars, but the risk of decompression sickness (DCS) during the extravehicular activity in a 3.75-psia suit, after exposure to any of the three habitat conditions, may limit unrestricted exploration. I evaluate here the risk of DCS since a significant proportion of a trinary breathing gas in the habitat might contain Ar. I draw on past experience and published information to extrapolate into untested, multivariable conditions to evaluate risk. A rigorous assessment of risk as a probability of DCS for each habitat condition is not yet possible. Based on many assumptions about Ar in hypobaric decompressions, I conclude that the presence of Ar significantly increases the risk of DCS. The risk is significant even with the best habitat option: 2.56 psia oxygen, 3.41 psia N2, and 2.20 psia Ar. Several hours of prebreathing 100% 02, a higher suit pressure, or a combination of other important variables such as limited exposure time on the surface or exercise during prebreathe would be necessary to reduce the risk of DCS to an acceptable level. The acceptable level for DCS risk on Mars has not yet been determined. Mars is a great distance from Earth and therefore from primary medical care. The acceptable risk would necessarily be defined by the capability to treat DCS in the Rover vehicle, in the habitat, or both.

  12. The Mars Project: Avoiding Decompression Sickness on a Distant Planet

    NASA Astrophysics Data System (ADS)

    Conkin, Johnny

    2000-05-01

    A cost-effective approach for Mars exploration is to use available resources, such as water and atmospheric gases. Nitrogen (N2) and argon (Ar) are available and could form the inert gas component of a habitat atmosphere at 8.0, 9.0, or 10.0 pounds per square inch (psia). The habitat and space suit are designed as an integrated system: a comfortable living environment about 85% of the time and a safe working environment about 15% of the time. A goal is to provide a system that permits unrestricted exploration of Mars, but the risk of decompression sickness (DCS) during the extravehicular activity in a 3.75-psia suit, after exposure to any of the three habitat conditions, may limit unrestricted exploration. I evaluate here the risk of DCS since a significant proportion of a trinary breathing gas in the habitat might contain Ar. I draw on past experience and published information to extrapolate into untested, multivariable conditions to evaluate risk. A rigorous assessment of risk as a probability of DCS for each habitat condition is not yet possible. Based on many assumptions about Ar in hypobaric decompressions, I conclude that the presence of Ar significantly increases the risk of DCS. The risk is significant even with the best habitat option: 2.56 psia oxygen, 3.41 psia N2, and 2.20 psia Ar. Several hours of prebreathing 100% 02, a higher suit pressure, or a combination of other important variables such as limited exposure time on the surface or exercise during prebreathe would be necessary to reduce the risk of DCS to an acceptable level. The acceptable level for DCS risk on Mars has not yet been determined. Mars is a great distance from Earth and therefore from primary medical care. The acceptable risk would necessarily be defined by the capability to treat DCS in the Rover vehicle, in the habitat, or both.

  13. Influence of decompression sickness on vasocontraction of isolated rat vessels.

    PubMed

    Mazur, Aleksandra; Lambrechts, Kate; Wang, Qiong; Belhomme, Marc; Theron, Michael; Buzzacott, Peter; Guerrero, François

    2016-04-01

    Studies conducted in divers indicate that endothelium function is impaired following a dive even without decompression sickness (DCS). Our previous experiment conducted on rat isolated vessels showed no differences in endothelium-dependent vasodilation after a simulated dive even in the presence of DCS, while contractile response to phenylephrine was progressively impaired with increased decompression stress. This study aimed to further investigate the effect of DCS on vascular smooth muscle. Thirty-two male Sprague-Dawley rats were submitted to the same hyperbaric protocol and classified according to the severity of DCS: no-DCS (without clinical symptoms), mild-DCS, or severe-DCS (dead within 1 h). A control group remained at atmospheric pressure. Isometric tension was measured in rings of abdominal aorta and mesenteric arteries. Single dose contraction was assessed with KCl solution. Dose-response curves were obtained with phenylephrine and endothelin-1. Phenylephrine-induced contraction was observed in the presence of antioxidant tempol. Additionally, plasma concentrations of angiotensin II, angiotensin-converting enzyme, and thiobarbituric acid reactive substances (TBARS) were assessed. Response to phenylephrine was impaired only among mild-DCS in both vessels. Dose-response curves to endothelin-1 were impaired after mild-DCS in mesenteric and severe-DCS in aorta. KCl-induced contraction was affected after hyperbaric exposure regardless of DCS status in aorta only. These results confirm postdive vascular dysfunction is dependent on the type of vessel. It further evidenced that vascular dysfunction is triggered by DCS rather than by diving itself and suggest the influence of circulating factor/s. Diving-induced impairment of the L-type voltage-dependent Ca(2+) channels and/or influence of renin-angiotensin system is proposed. PMID:26769950

  14. Two Portal Percutaneous Endoscopic Decompression for Lumbar Spinal Stenosis: Preliminary Study

    PubMed Central

    Dilokhuttakarn, Thitinut

    2016-01-01

    Study Design Retrospective. Purpose To report the outcomes of patients with lumbar spinal stenosis treated with percutaneous endoscopic decompression, focusing on the results of clinical evaluations. Overview of Literature There are no studies about two portal percutaneous endoscopic decompression in the treatment of lumbar spinal stenosis. Methods Medical and surgical complications were examined and clinical results were analyzed for 30 patients who consecutively underwent two portal percutaneous endoscopic decompression for lumbar spinal stenosis were reviewed. The operations were performed by unilateral laminotomy for bilateral decompression. Results All patients displayed clinical improvement when were evaluated with visual analog scale (VAS) score of pain, Oswestry disability index (ODI) and Macnab criteria. The improvement of VAS and ODI was 8.3±0.7 to 2.3±2.6 and 65.2±13.7 to 24.0±15.5, respectively (both p<0.05). Complications were the same as for open decompression. The most common complication was transient nerve root paresthesia. Conclusions Surgical decompression with two portal percutaneous endoscopic decompression has initial benefits, but long-term studies should pay more attention to the risks of postoperative instability and restenosis as well as the need for re-operation. Further investigations with long-term results are thus required. PMID:27114776

  15. Evaluation of Decompression and Interlaminar Stabilization Compared with Decompression and Fusion for the Treatment of Lumbar Spinal Stenosis: 5-year Follow-up of a Prospective, Randomized, Controlled Trial

    PubMed Central

    Lauryssen, Carl; Davis, Reginald J.; Bae, Hyun W.; Peloza, John H.; Guyer, Richard D.; Zigler, Jack E.; Ohnmeiss, Donna D.; Leary, Scott

    2016-01-01

    Introduction If nonoperative treatment for lumbar stenosis fails, surgery may be considered. This traditionally includes decompression often combined with fusion. Desire for less extensive surgery led to developing new techniques and implants, including an interlaminar device designed with the goal of providing segmental stability without fusion, following decompression. The purpose of this study was to investigate 5-year outcomes associated with an interlaminar device. Methods This prospective, randomized, controlled trial was conducted at 21 centers. Patients with moderate to severe lumbar stenosis at one or two contiguous levels and up to Grade I spondylolisthesis were randomized (2:1 ratio) to decompression and interlaminar stabilization (D+ILS; n=215) using the coflex® Interlaminar Stabilization® device (Paradigm Spine, LLC) or decompression and fusion with pedicle screws (D+PS; n=107). Clinical evaluations were made preoperatively and at 6 weeks and 3, 6, 12, 18, 24, 36, 48, and 60 months postoperatively. Overall Food and Drug Administration success criteria required that a patient meet 4 criteria: 1) >15 point improvement in Oswestry Disability Index (ODI) score; 2) no reoperation, revision, removal, or supplemental fixation; 3) no major device-related complication; and 4) no epidural steroid injection after surgery. Results At 5 years, 50.3% of D+ILS vs. 44% of D+PS patients (p>0.35) met the composite success criteria. Reoperation/revision rates were similar in the two groups (16.3% vs. 17.8%; p >0.90). Both groups had statistically significant improvement through 60 months in ODI scores with 80.6% of D+ILS patients and 73.2% of D+PS patients demonstrating >15 point improvement (p>0.30). VAS, SF-12, and ZCQ scores followed a similar pattern of maintained significant improvement throughout follow-up. On the SF-12 and ZCQ, D+ILS group scores were statistically significantly better during early follow-up compared to D+PS. In the D+ILS group, foraminal height

  16. The effect of exercise on venous gas emboli and decompression sickness in human subjects at 4.3 psia

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Waligora, James M.; Horrigan, David J., Jr.; Hadley, Arthur T., III

    1987-01-01

    The contribution of upper body exercise to altitude decompression sickness while at 4.3 psia after 3.5 or 4.0 hours of 100% oxygen prebreathing at 14.7 psia was determined by comparing the incidence and patterns of venous gas emboli (VGE), and the incidence of Type 1 decompression sickness (DCS) in 43 exercising male subjects and 9 less active male Doppler Technicians (DT's). Each subject exercised for 4 minutes at each of 3 exercise stations while at 4.3 psia. An additional 4 minutes were spent monitoring for VGE by the DT while the subject was supine on an examination cot. In the combined 3.5 and 4.0 hour oxygen prebreathe data, 13 subjects complained of Type 1 DCS compared to 9 complaints from DT's. VGE were detected in 28 subjects compared to 14 detections from DT's. A chi-square analysis of proportions showed no statistically significantly difference in the incidence of Type 1 DCS or VGE between the two groups; however, the average time to detect VGE and to report Tyep 1 DCS symptoms were statistically different. It was concluded that 4 to 6 hours of upper body exercise at metabolic rates simulating EVA metabolic rates hastens the initial detection of VGE and the time to report Type 1 DCS symptoms as compared to DT's.

  17. Surgical variation of microvascular decompression for trigeminal neuralgia: A technical note and anatomical study

    PubMed Central

    da Silva, Otávio T.; de Almeida, César C.; Iglesio, Ricardo F.; de Navarro, Jessie M.; Teixeira, Manoel J.; Duarte, Kleber P.

    2016-01-01

    Background: In this article, the authors described their experience in microvascular decompression for trigeminal neuralgia. Methods: The microvascular decompression technique used in the authors’ institution is described in a step by step manner with some illustrative cases as well as a cadaver dissection to highlight the differences with other previously described techniques. Results: Since 2013, 107 patients were operated in the Neurosurgery Division of the University of São Paulo using the described technique, with a shorter operative time and avoiding cerebellar retractor compared with classic techniques. Conclusion: Our modified microvascular decompression technique for trigeminal neuralgia can be used with safety and efficiency for treating trigeminal neuralgia. PMID:27625893

  18. Bilateral massive pulmonary embolism secondary to decompression sickness: a case report.

    PubMed

    Gaye, Ulubay; Sevinc, Sarinc Ulasli; Ozgur, Karacan; Tuna, Gumus; Fusun, Eyuboglu Oner

    2007-01-01

    This case report describes massive pulmonary embolism in a patient as a complication of decompression illness. Twenty-four hours after a scuba dive, a 50-year-old man developed acute pulmonary hypertension and decompression sickness that produced bilateral embolism in the lung at day 6 of hospitalization. He had no risk factor for pulmonary embolism earlier except smoking. Decompression sickness that RESULTS in formation of bubbles of inert gas is a risk for both aviators and divers. The present case strongly suggests that micro-bubbles may cause life-threatening massive pulmonary embolism. PMID:18005806

  19. A current review of core decompression in the treatment of osteonecrosis of the femoral head.

    PubMed

    Pierce, Todd P; Jauregui, Julio J; Elmallah, Randa K; Lavernia, Carlos J; Mont, Michael A; Nace, James

    2015-09-01

    The review describes the following: (1) how traditional core decompression is performed, (2) adjunctive treatments, (3) multiple percutaneous drilling technique, and (4) the overall outcomes of these procedures. Core decompression has optimal outcomes when used in the earliest, precollapse disease stages. More recent studies have reported excellent outcomes with percutaneous drilling. Furthermore, adjunct treatment methods combining core decompression with growth factors, bone morphogenic proteins, stem cells, and bone grafting have demonstrated positive results; however, larger randomized trial is needed to evaluate their overall efficacy. PMID:26045085

  20. Rationale, Science, and Economics of Surgical Nerve Decompression for Diabetic Neuropathy Foot Complications.

    PubMed

    Nickerson, David Scott

    2016-04-01

    Nerve decompression is effective and safe for dealing with the pain and numbness symptoms of the frequent nerve compression entrapments in diabetic symmetric peripheral neuropathy (DSPN). Evidence has accumulated of balance and stability improvements and protection against diabetic foot ulceration, recurrence and its complication cascade. Nerve decompression proffers significant benefit versus the large socioeconomic costs of DSPN complications. Advancing understanding of the mechanism of nerve compression and altered axonal activity in diabetes clarifies the basis of clinical benefit. Clinicians should seek out and recognize nerve entrapments and consider advising nerve decompression for relief of DSPN symptoms and prevention of complications. PMID:27013417

  1. Therapeutic sustainability and durability of coflex interlaminar stabilization after decompression for lumbar spinal stenosis: a four year assessment

    PubMed Central

    Bae, Hyun W.; Lauryssen, Carl; Maislin, Greg; Leary, Scott

    2015-01-01

    Background Approved treatment modalities for the surgical management of lumbar spinal stenosis encompass a variety of direct and indirect methods of decompression, though all have varying degrees of limitations and morbidity which potentially limit the efficacy and durability of the treatment. The coflex® interlaminar stabilization implant (Paradigm Spine, New York, NY), examined under a United States Food and Drug Administration (US FDA) Investigational Device Exemption (IDE) clinical trial, is shown to have durable outcomes when compared to posterolateral fusion in the setting of post-decompression stabilization for stenotic patients. Other clinical and radiographic parameters, more indicative of durability, were also evaluated. The data collected from these parameters were used to expand the FDA composite clinical success (CCS) endpoint; thus, creating a more stringent Therapeutic Sustainability Endpoint (TSE). The TSE allows more precise calculation of the durability of interlaminar stabilization (ILS) when compared to the fusion control group. Methods A retrospective analysis of data generated from a prospective, randomized, level-1 trial that was conducted at 21 US sites was carried out. Three hundred forty-four per-protocol subjects were enrolled and randomized to ILS or fusion after decompression for lumbar stenosis with up to grade 1 degenerative spondylolisthesis. Clinical, safety, and radiographic data were collected and analyzed in both groups. Four-year outcomes were assessed, and the TSE was calculated for both cohorts. The clinical and radiographic factors thought to be associated with therapeutic sustainability were added to the CCS endpoints which were used for premarket approval (PMA). Results Success rate, comprised of no second intervention and an ODI improvement of ≥ 15 points, was 57.6% of ILS and 46.7% of fusion patients (p = 0.095). Adding lack of fusion in the ILS cohort and successful fusion in the fusion cohort showed a CCS of 42

  2. The Relationship between Behavior Ratings and Concurrent and Subsequent Mental and Motor Performance in Toddlers Born at Extremely Low Birth Weight

    ERIC Educational Resources Information Center

    Messinger, Daniel; Lambert, Brittany; Bauer, Charles R.; Bann, Carla M.; Hamlin-Smith, Kasey; Das, Abhik

    2010-01-01

    When predicting child developmental outcomes, reliance on children's scores on measures of developmental functioning alone might mask more subtle behavioral difficulties, especially in children with developmental risk factors. The current study examined predictors and stability of examiner behavior ratings and their association with concurrent and…

  3. Fluoxetine Protection in Decompression Sickness in Mice is Enhanced by Blocking TREK-1 Potassium Channel with the “spadin” Antidepressant

    PubMed Central

    Vallée, Nicolas; Lambrechts, Kate; De Maistre, Sébastien; Royal, Perrine; Mazella, Jean; Borsotto, Marc; Heurteaux, Catherine; Abraini, Jacques; Risso, Jean-Jacques; Blatteau, Jean-Eric

    2016-01-01

    In mice, disseminated coagulation, inflammation, and ischemia induce neurological damage that can lead to death. These symptoms result from circulating bubbles generated by a pathogenic decompression. Acute fluoxetine treatment or the presence of the TREK-1 potassium channel increases the survival rate when mice are subjected to an experimental dive/decompression protocol. This is a paradox because fluoxetine is a blocker of TREK-1 channels. First, we studied the effects of an acute dose of fluoxetine (50 mg/kg) in wild-type (WT) and TREK-1 deficient mice (knockout homozygous KO and heterozygous HET). Then, we combined the same fluoxetine treatment with a 5-day treatment protocol with spadin, in order to specifically block TREK-1 activity (KO-like mice). KO and KO-like mice were regarded as antidepressed models. In total, 167 mice (45 WTcont 46 WTflux 30 HETflux and 46 KOflux) constituting the flux-pool and 113 supplementary mice (27 KO-like 24 WTflux2 24 KO-likeflux 21 WTcont2 17 WTno dive) constituting the spad-pool were included in this study. Only 7% of KO-TREK-1 treated with fluoxetine (KOflux) and 4% of mice treated with both spadin and fluoxetine (KO-likeflux) died from decompression sickness (DCS) symptoms. These values are much lower than those of WT control (62%) or KO-like mice (41%). After the decompression protocol, mice showed significant consumption of their circulating platelets and leukocytes. Spadin antidepressed mice were more likely to exhibit DCS. Nevertheless, mice which had both blocked TREK-1 channels and fluoxetine treatment were better protected against DCS. We conclude that the protective effect of such an acute dose of fluoxetine is enhanced when TREK-1 is inhibited. We confirmed that antidepressed models may have worse DCS outcomes, but concomitant fluoxetine treatment not only decreased DCS severity but increased the survival rate. PMID:26909044

  4. Decompression Illness: Clinical Aspects of 5278 Consecutive Cases Treated in a Single Hyperbaric Unit

    PubMed Central

    Xu, Wenbing; Liu, Wenwu; Huang, Guoyang; Zou, ZiJiao; Cai, Zhiyu; Xu, Weigang

    2012-01-01

    Background Decompression illness (DCI) is a major concern in pressure-related activities. Due to its specific prerequisite conditions, DCI is rare in comparison with other illnesses and most physicians are inexperienced in treatment. In a fishery area in northern China, during the past decade, tens of thousands of divers engaged in seafood harvesting and thousands suffered from DCI. We established a hyperbaric facility there and treated the majority of the cases. Methods and Results A total of 5,278 DCI cases were admitted in our facility from February 2000 through December 2010 and treated using our recompression schedules. Cutaneous abnormalities, joint and muscular pain and neurological manifestations were three most common symptoms. The initial symptom occurred within 6 h after surfacing in 98.9% of cases, with an overall median latency of 62 min. The shorter the latent time, the more serious the symptoms would be (P<0.0001). Nine cases died before recompression and 5,269 were treated using four recompression schedules, with an overall effectiveness rate of 99.3%. The full recovery rate decreased with the increase of the delay from the onset of symptoms to the treatment (P<0.0001). Conclusions DCI presents specific occurrence rules. Recompression should be administered as soon as possible and should never be abandoned irrespective of the delay. The recompression schedules used were effective and flexible for variety conditions of DCI. PMID:23185538

  5. Emergency decompression of tension retrobulbar emphysema secondary to orbital floor fracture.

    PubMed

    Tomasetti, Patrick; Jacbosen, Christine; Gander, Thomas; Zemann, Wolfgang

    2013-01-01

    Orbital floor fractures are generally the result of blowout orbital and may be associated with orbital emphysema leading to proptosis and even to loss of vision. A 49-year-old woman fractured the orbital floor in a fall. After blowing her nose, she developed exophthalmos and severe reduction in vision. She consulted our department and underwent emergency surgical management with orbital drainage. Decompression led to immediate resolution of the exophthalmos and postoperative improvement in visual acuity. Urgent decompression is indicated by the presence of proptosis, elevated intraocular pressure, and progressive loss of vision in cases of orbital trauma with additional emphysema. Surgical treatment of tension emphysema includes lateral canthotomy or cantholysis, needle aspiration, transconjunctival, or lateral blepharoplasty approach, and bone decompression depending on the severity of the case. Sneezing or blowing the nose can lead to proptosis and decreased visual acuity secondary to trauma to the orbit. Under such circumstances, emergency decompression is essential. PMID:24964422

  6. Decompression, enucleation, and implant placement in the management of a large dentigerous cyst.

    PubMed

    Cakarer, Sirmahan; Selvi, Firat; Isler, Sabri Cemil; Keskin, Cengizhan

    2011-05-01

    The dentigerous cyst is a developmental odontogenic cyst, accounting for 10% of all cysts of the jaws. The treatment options are decompression, marsupialization, or enucleation regarding the features of the lesions. In this article, a case of a 17-year-old adolescent girl having a large mandibular dentigerous cyst associated with an unerupted third molar is presented. The treatment is composed of decompression for 6 months and enucleation. Decompression and enucleation are a predictable choice in the treatment of large cysts. Radiologic evaluation is mandatory to decide for the appropriate time for the removal of the decompression stents, the enucleation time, and also for the evaluation of the adequate new bone formation for implant placement. The present case emphasizes the success of a conservative approach in the management of a large dentigerous cyst in a young patient and also the maintenance of the new bone formation without using any graft materials for the placement of dental implants. PMID:21558915

  7. The microendoscopic decompression of lumbar stenosis: a review of the current literature and clinical results.

    PubMed

    Wong, Albert P; Smith, Zachary A; Lall, Rohan R; Bresnahan, Lacey E; Fessler, Richard G

    2012-01-01

    Lumbar stenosis is a well-defined pathologic condition with excellent surgical outcomes. Empiric evidence as well as randomized, prospective trials has demonstrated the superior efficacy of surgery compared to medical management for lumbar stenosis. Traditionally, lumbar stenosis is decompressed with open laminectomies. This involves removal of the spinous process, lamina, and the posterior musculoligamentous complex (posterior tension band). This approach provides excellent improvement in symptoms, but is also associated with potential postoperative spinal instability. This may result in subsequent need for spinal fusion. Advances in technology have enabled the application of minimally invasive spine surgery (MISS) as an acceptable alternative to open lumbar decompression. Recent studies have shown similar to improved perioperative outcomes when comparing MISS to open decompression for lumbar stenosis. A literature review of MISS for decompression of lumbar stenosis with tubular retractors was performed to evaluate the outcomes of this modern surgical technique. In addition, a discussion of the advantages and limitations of this technique is provided. PMID:22900163

  8. The Microendoscopic Decompression of Lumbar Stenosis: A Review of the Current Literature and Clinical Results

    PubMed Central

    Wong, Albert P.; Smith, Zachary A.; Lall, Rohan R.; Bresnahan, Lacey E.; Fessler, Richard G.

    2012-01-01

    Lumbar stenosis is a well-defined pathologic condition with excellent surgical outcomes. Empiric evidence as well as randomized, prospective trials has demonstrated the superior efficacy of surgery compared to medical management for lumbar stenosis. Traditionally, lumbar stenosis is decompressed with open laminectomies. This involves removal of the spinous process, lamina, and the posterior musculoligamentous complex (posterior tension band). This approach provides excellent improvement in symptoms, but is also associated with potential postoperative spinal instability. This may result in subsequent need for spinal fusion. Advances in technology have enabled the application of minimally invasive spine surgery (MISS) as an acceptable alternative to open lumbar decompression. Recent studies have shown similar to improved perioperative outcomes when comparing MISS to open decompression for lumbar stenosis. A literature review of MISS for decompression of lumbar stenosis with tubular retractors was performed to evaluate the outcomes of this modern surgical technique. In addition, a discussion of the advantages and limitations of this technique is provided. PMID:22900163

  9. Cervicogenic vertigo treated by c1 transverse foramen decompression : a case report.

    PubMed

    Park, Junhee; Lee, Chulkyu; You, Namkyu; Kim, Sanghyun; Cho, Kihong

    2014-09-01

    Cervicogenic vertigo was known as Bow hunter's syndrome. Occlusion of vertebral artery causes vertebrobasilar insufficiency and we reported cervicogenic vertigo case which was treated by simple decompression of transverse foramen of C1. The patient was 48 years old female who had left side dominant vertebral artery and vertigo was provoked when she rotated her head to right side. Angiography showed complete obliteration of blood flow of left vertebral artery when her head was rotated to right side. The operation was decompression of left vertebral artery at C1 level. Posterior wall of transverse foramen was resected and vertebral artery was exposed and decompressed. After surgery, vertigo of the patient was disappeared, and angiography showed patent left vertebral artery when her head was rotated to right side. Vertigo caused by compression of cervical vertebral artery could be treated by decompression without fusion or instrumentation, especially in C1 transverse foramen. PMID:25346772

  10. The dynamic of nasogastric decompression after esophagectomy and its predictive value of postoperative complications

    PubMed Central

    Zhao, Yan; Guo, Jie; You, Bin; Hou, Shengcai; Hu, Bin

    2016-01-01

    Background To investigate the regularity and the influence factors of nasogastric decompression volume after esophagectomy, and explore whether the volume of nasogastric decompression can be employed as a predictor for postoperative complications of esophageal carcinoma. Methods Consecutive 247 patients with esophageal cancer who underwent esophagectomy were retrospectively evaluated. The volume of postoperative nasogastric decompression was recorded and the regularity based on it was described. The single and multiple factors regression analysis were used to find out relative factors of the nasogastric decompression volume among the patients without postoperative complication. Gender, age, height, weight, tobacco or alcohol exposure, location of the tumor, histological type, pathological staging, operation time, surgical procedures, anastomotic position and gastric conduit reconstruction were considered as the independent variable. Then, verify the former regression models using the data of patients with postoperative complications. Results In trend analysis, the curve estimation revealed a quadratic trend in the relationship between nasogastric decompression volume and postoperative days (R2 =0.890, P=0.004). The volume of postoperative nasogastric decompression was described by daily drainage (mL) =82.215 + 69.620 × days − 6.604 × days2. The results of multiple linear stepwise regression analysis showed that gastric conduit reconstruction (β=0.410, P=0.000), smoking (β=−0.231, P=0.000), age (β=−0.193, P=0.001) and histological type of the tumor (β=−0.169, P=0.006) were significantly related to the volume of nasogastric decompression. The average drainage in 5 days after surgery =262.287 + 132.873 × X1 − 72.160 × X2 − 27.904 × X3 − 36.368 × X4 (X1, gastric conduit reconstruction; X2, smoking; X3, histological type; X4, age). The nasogastric decompression of the patients with delayed gastric emptying, and lung infection statistically differ

  11. Exploiting Aerobic Fitness To Reduce Risk Of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Gernhardt, Michael L.; Wessel, James H., III

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). METHODS: Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 +/- 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 +/- 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. RESULTS: An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). CONCLUSIONS: A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  12. Exploiting Aerobic Fitness to Reduce Risk of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Gernhardt, M. L.; Wessel, J. H.

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 plus or minus 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 plus or minus 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  13. Decompressive craniectomy in traumatic brain injury: the randomized multicenter RESCUEicp study (www.RESCUEicp.com).

    PubMed

    Hutchinson, P J; Corteen, E; Czosnyka, M; Mendelow, A D; Menon, D K; Mitchell, P; Murray, G; Pickard, J D; Rickels, E; Sahuquillo, J; Servadei, F; Teasdale, G M; Timofeev, I; Unterberg, A; Kirkpatrick, P J

    2006-01-01

    The RESCUEicp (Randomized Evaluation of Surgery with Craniectomy for Uncontrollable Elevation of intracranial pressure) study has been established to determine whether decompressive craniectomy has a role in the management of patients with traumatic brain injury and raised intracranial pressure that does not respond to initial treatment measures. We describe the concept of decompressive craniectomy in traumatic brain injury and the rationale and protocol of the RESCUEicp study. PMID:16671415

  14. A meta-analysis of selective versus routine nasogastric decompression after elective laparotomy.

    PubMed Central

    Cheatham, M L; Chapman, W C; Key, S P; Sawyers, J L

    1995-01-01

    OBJECTIVE: A meta-analysis of all published clinical trials comparing selective versus routine nasogastric decompression was performed in an attempt to evaluate the need for nasogastric decompression after elective laparotomy. BACKGROUND: Many studies have suggested that routine nasogastric decompression is unnecessary after elective laparotomy and may be associated with an increased incidence of complications. Despite these reports, many surgeons continue to practice routine nasogastric decompression, believing that its use significantly decreases the risk of postoperative nausea, vomiting, aspiration, wound dehiscence, and anastomotic leak. METHODS: A comprehensive search of the English language medical literature was performed to identify all published clinical trials evaluating nasogastric decompression. Twenty-six trials (3964 patients) met inclusion criteria. The outcome data extracted from each trial were subsequently "pooled" and analyzed for significant differences using the Mantel-Haenszel estimation of combined relative risk. RESULTS: Fever, atelectasis, and pneumonia were significantly less common and days to first oral intake were significantly fewer in patients managed without nasogastric tubes. Meta-analysis based on study quality revealed significantly fewer pulmonary complications, but significantly greater abdominal distension and vomiting in patients managed without nasogastric tubes. Routine nasogastric decompression did not decrease the incidence of any other complication. CONCLUSIONS: Although patients may develop abdominal distension or vomiting without a nasogastric tube, this is not associated with an increase in complications or length of stay. For every patient requiring insertion of a nasogastric tube in the postoperative period, at least 20 patients will not require nasogastric decompression. Routine nasogastric decompression is not supported by meta-analysis of the literature. PMID:7748028

  15. Left Atrial Decompression by Percutaneous Left Atrial Venting Cannula Insertion during Venoarterial Extracorporeal Membrane Oxygenation Support

    PubMed Central

    Kim, Ha Eun; Jung, Jo Won; Shin, Yu Rim; Park, Han Ki; Park, Young Hwan; Shin, Hong Ju

    2016-01-01

    Patients with venoarterial extracorporeal membrane oxygenation (ECMO) frequently suffer from pulmonary edema due to left ventricular dysfunction that accompanies left heart dilatation, which is caused by left atrial hypertension. The problem can be resolved by left atrium (LA) decompression. We performed a successful percutaneous LA decompression with an atrial septostomy and placement of an LA venting cannula in a 38-month-old child treated with venoarterial ECMO for acute myocarditis. PMID:27298800

  16. Relationship between the clinical features of neurological decompression illness and its causes.

    PubMed

    Wilmshurst, P; Bryson, P

    2000-07-01

    There is dispute as to whether paradoxical gas embolism is an important aetiological factor in neurological decompression illness, particularly when the spinal cord is affected. We performed a blind case-controlled study to determine the relationship between manifestations of neurological decompression illness and causes in 100 consecutive divers with neurological decompression illness and 123 unaffected historical control divers. The clinical effects of neurological decompression illness (including the sites of lesions and latency of onset) were correlated with the presence of right-to-left shunts, lung disease and a provocative dive profile. The prevalence and size of shunts determined by contrast echocardiography were compared in affected divers and controls. Right-to-left shunts, particularly those which were large and present without a Valsalva manoeuvre, were significantly more common in divers who had neurological decompression illness than in controls (P<0.001). Shunts graded as large or medium in size were present in 52% of affected divers and 12.2% of controls (P<0.001). Spinal decompression illness occurred in 26 out of 52 divers with large or medium shunts and in 12 out of 48 without (P<0.02). The distribution of latencies of symptoms differed markedly in the 52 divers with a large or medium shunt and in the 30 divers who had lung disease or a provocative dive profile. In most cases of neurological decompression illness the cause can be determined by taking a history of the dive profile and latency of onset, and by performing investigations to detect a right-to-left shunt and lung disease. Using this information it is possible to advise divers on the risk of returning to diving and on ways of reducing the risk if diving is resumed. Most cases of spinal decompression illness are associated with a right-to-left shunt. PMID:10887059

  17. The role of computed tomography in the assessment of neurologic sequelae of decompression sickness.

    PubMed

    Hodgson, M; Beran, R G; Shirtley, G

    1988-09-01

    Computed tomographic (CT) scans were performed on 47 patients who had received recompression treatment for decompression sickness. A retrospective review of the case notes disclosed that 24 of the 47 patients had symptoms that suggested cerebral involvement. None of the reported CT abnormalities could be correlated with the clinical manifestations at presentation. It was concluded that the CT scan is not a cost-effective investigative tool for the posttreatment evaluation of decompression sickness. PMID:3415521

  18. Effect of Decompressive Craniectomy on Perihematomal Edema in Patients with Intracerebral Hemorrhage

    PubMed Central

    Klinger-Gratz, Pascal P.; Fiechter, Michael; Z’Graggen, Werner J.; Gautschi, Oliver P.; El-Koussy, Marwan; Gralla, Jan; Schaller, Karl; Zbinden, Martin; Arnold, Marcel; Fischer, Urs; Mattle, Heinrich P.; Raabe, Andreas; Beck, Jürgen

    2016-01-01

    Background Perihematomal edema contributes to secondary brain injury in the course of intracerebral hemorrhage. The effect of decompressive surgery on perihematomal edema after intracerebral hemorrhage is unknown. This study analyzed the course of PHE in patients who were or were not treated with decompressive craniectomy. Methods More than 100 computed tomography images from our published cohort of 25 patients were evaluated retrospectively at two university hospitals in Switzerland. Computed tomography scans covered the time from admission until day 100. Eleven patients were treated by decompressive craniectomy and 14 were treated conservatively. Absolute edema and hematoma volumes were assessed using 3-dimensional volumetric measurements. Relative edema volumes were calculated based on maximal hematoma volume. Results Absolute perihematomal edema increased from 42.9 ml to 125.6 ml (192.8%) after 21 days in the decompressive craniectomy group, versus 50.4 ml to 67.2 ml (33.3%) in the control group (Δ at day 21 = 58.4 ml, p = 0.031). Peak edema developed on days 25 and 35 in patients with decompressive craniectomy and controls respectively, and it took about 60 days for the edema to decline to baseline in both groups. Eight patients (73%) in the decompressive craniectomy group and 6 patients (43%) in the control group had a good outcome (modified Rankin Scale score 0 to 4) at 6 months (P = 0.23). Conclusions Decompressive craniectomy is associated with a significant increase in perihematomal edema compared to patients who have been treated conservatively. Perihematomal edema itself lasts about 60 days if it is not treated, but decompressive craniectomy ameliorates the mass effect exerted by the intracerebral hemorrhage plus the perihematomal edema, as reflected by the reduced midline shift. PMID:26872068

  19. Alternative technique in atypical spinal decompression: the use of the ultrasonic scalpel in paediatric achondroplasia.

    PubMed

    Woodacre, Timothy; Sewell, Matthew; Clarke, Andrew J; Hutton, Mike

    2016-01-01

    Spinal stenosis can be a very disabling condition. Surgical decompression carries a risk of dural tear and neural injury, which is increased in patients with severe stenosis or an atypical anatomy. We present an unusual case of symptomatic stenosis secondary to achondroplasia presenting in a paediatric patient, and highlight a new surgical technique used to minimise the risk of dural and neural injury during decompression. PMID:27288205

  20. Decompressive surgery for malignant supratentorial infarction remains underutilized after guideline publication.

    PubMed

    Bar, Michal; Mikulik, Robert; Skoloudik, David; Czerny, Daniel; Lipina, Radim; Sames, Martin; Choc, Milan; Novak, Zdenek; Stary, Marian; Benes, Vladimir; Smrcka, Martin; Filip, Michal; Vondrackova, Denisa; Chlouba, Vladimir; Suchomel, Petr; Haninec, Pavel; Brzezny, Richard; Juran, Vilem

    2011-09-01

    Decompressive surgery <48 h from stroke onset reduces the prevalence of mortality and morbidity from malignant supratentorial infarction. We investigated if utilization of decompressive surgery changed in the Czech Republic (CZ) after the release of new guidelines regarding treatment of malignant brain infarction. The volume of decompressive surgery in 2009 in all centers in the CZ was assessed using the same methodology as in 2006. All neurosurgery departments in the CZ were asked to complete a questionnaire and asked to identify all cases of decompressive surgery for malignant brain infarction through a combination of discharge codes for "brain infarction" and "decompressive surgery" from electronic hospital charts. Data for 56 patients were obtained from 15 of the 16 neurosurgery departments in the CZ. The average age was 53 ± 13; number of males 20; median time to surgery was 48 h (range 24-62); median NIHSS score was 25 (IQR, 20-30); median infarct volume was 300 cm(3) [interquartile (IQR, 250-350)]; mean shift on CT was 10.6 ± 3.6 mm and size of hemicraniectomy was 125 cm(2) (IQR, 110-154). A favorable outcome was achieved in 45% of the patients. The number of procedures increased from 39 in 2,006 to 2,056 in 2009. Based on data from one stroke center, 10% suffered from malignant supratentorial infarction and 2.3% met the criteria for decompressive surgery. In 2009, as compared to 2006, the volume of decompressive surgery carried out moderately increased. However, procedures remained underutilized because only ~10% of those who needed decompressive surgery underwent surgery. PMID:21431893

  1. Perioperative and long-term operative outcomes after surgery for trigeminal neuralgia: microvascular decompression vs percutaneous balloon ablation

    PubMed Central

    Jellish, W Scott; Benedict, William; Owen, Kevin; Anderson, Douglas; Fluder, Elaine; Shea, John F

    2008-01-01

    Objectives Numerous medical and surgical therapies have been utilized to treat the symptoms of trigeminal neuralgia (TN). This retrospective study compares patients undergoing either microvascular decompression or balloon ablation of the trigeminal ganglion and determines which produces the best long-term outcomes. Methods A 10-year retrospective chart review was performed on patients who underwent microvascular decompression (MVD) or percutaneous balloon ablation (BA) surgery for TN. Demographic data, intraoperative variables, length of hospitalization and symptom improvement were assessed along with complications and recurrences of symptoms after surgery. Appropriate statistical comparisons were utilized to assess differences between the two surgical techniques. Results MVD patients were younger but were otherwise similar to BA patients. Intraoperatively, twice as many BA patients developed bradycardia compared to MVD patients. 75% of BA patients with bradycardia had an improvement of symptoms. Hospital stay was shorter in BA patients but overall improvement of symptoms was better with MVD. Postoperative complication rates were similar (21% vs 26%) between the BA and MVD groups. Discussion MVD produced better overall outcomes compared to BA and may be the procedure of choice for surgery to treat TN. PMID:18597696

  2. Verification of an altitude decompression sickness prevention protocol for Shuttle operations utilizing a 10.s psi pressure stage

    NASA Technical Reports Server (NTRS)

    Waligora, J. M.; Horrigan, D. J., Jr.; Conkin, J.; Hadley, A. T., III

    1984-01-01

    Three test series involving 173-man tess were conducted to define and verify a pre-extravehicular activity (EVA) denitrogenation procedure that would provide acceptable protection against altitude decompression sickness while minimizing the required duration of oxygen (O2) prebreathe in the suit prior to EVA. The tests also addressed the safety, in terms of incidence of decompression sickness, of conducting EVA's on consecutive days rather than on alternate days. The tests were conducted in an altitude chamber, subjects were selected as representative of the astronaut population, and EVA periods were simulated by reducing the chamber pressure to suit pressure while the subjects breathed O2 with masks and worked at EVA representative work rates. A higher than anticipated incidence of both venous bubbles (55%) and symptoms (26%) was measured following all denitrogenation protocols in this test. For the most part, symptoms were very minor and stabilized, diminished, or disappeared in the six-hour tests. Instances of clear, possible, or potential systemic symptoms were encountered only after use of the unmodified 10.2 psi protocol and not after the modified 10.2 psi protocol, the 3.5-hour O2 prebreathed protocol, or the 4.0-hour O2 prebreathe protocol. The high incidence of symptoms is ascribed to the type and duration of exercise and the sensitivity of the reporting technique to minor symptoms. Repeated EVA exposures after only 17 hours did not increase symptom or bubble incidence.

  3. Kinetic and dynamic models of diving gases in decompression sickness prevention.

    PubMed

    Ball, Robert; Schwartz, Sorell L

    2002-01-01

    Decompression sickness is a complex phenomenon involving gas exchange, bubble dynamics and tissue response. Relatively simple deterministic compartmental models using empirically derived parameters have been the mainstay of the practice for preventing decompression sickness since the early 1900s. Decades of research have improved our understanding of decompression physiology, and the insights incorporated in decompression models have allowed people to dive deeper into the ocean. However, these efforts have not yet, and are unlikely in the near future, to result in a 'universal' deterministic model that can predict when decompression sickness will occur. Divers using current recreational dive computers need to be aware of their limitations. Probabilistic models based on the estimation of parameters using modern statistical methods from large databases of dives offer a new approach and can provide a means of standardisation of deterministic models. Future improvements in decompression practice will depend on continued improvement in understanding the kinetics and dynamics of gas exchange, bubble evolution and tissue response, and the incorporation of this knowledge in risk models whose parameters can be estimated from large databases of human and animal data. PMID:12074688

  4. Differential expression of inducible nitric oxide synthase in keratocystic odontogenic tumors prior and subsequent to decompression

    PubMed Central

    XU, WEI; SONG, XIAOMENG; ZHANG, XIAOMIN; WANG, ZHAO; DING, XU; YUAN, YE; WU, YUNONG; WU, HEMING

    2016-01-01

    The aim of the present study was to investigate the expression of inducible nitric oxide synthase (iNOS) in keratocystic odontogenic tumors (KCOTs) prior and subsequent to decompression and to explore the association between iNOS expression and changes in clinical features. Sixteen pairs of specimens obtained at the time of decompression and subsequent curettages were collected and immunohistochemically examined using an antibody against iNOS. The intensity of iNOS staining was evaluated semi-quantitatively for statistical analysis. Prior to decompression, 87.5% of KCOT samples showed no immunohistochemical reactivity for iNOS. Only 12.5% of samples exhibited slight staining for iNOS in the cytoplasm of cells in the epithelial layer. Subsequent to decompression, all the samples exhibited moderate to intense staining for iNOS in the cytoplasm and membrane of cells in the epithelial and fibrous layers. This increased expression of iNOS following decompression was statistically significant (P<0.01). The results demonstrated distinct expression of iNOS in KCOT samples prior and subsequent to decompression, indicating that iNOS may have a role in mediating changes in clinical features. PMID:27073658

  5. A preliminary study on surgical navigation for epiduroscopic laser neural decompression.

    PubMed

    Jeon, Sangseo; Lee, Gun Woo; Jeon, Young Dae; Park, Il-Hyung; Hong, Jaesung; Kim, Jae-Do

    2015-10-01

    Epiduroscopic laser neural decompression is an emerging therapeutic modality to treat lumbar spine pathologies including chronic low back pain, spinal stenosis, and disk herniation via catheter insertion followed by laser ablation of the lesion. Despite the efficacy of epiduroscopic laser neural decompression, excessive radiation doses due to fluoroscopy during epiduroscopic laser neural decompression have limited its widespread application. To address the issue, we propose a surgical navigation system to assist in epiduroscopic laser neural decompression procedures using radiation-free image guidance. An electromagnetic tracking system was used as the basic modality to track the internal location of the surgical instrument with respect to the patient body. Patient-to-image registration was carried out using the point-based registration method to determine the transformation between the coordinate system of the patient and that of the medical images. We applied the proposed system in epiduroscopic laser neural decompression procedures to assess its effectiveness, and the outcomes confirmed its clinical feasibility. To the best of our knowledge, this is a report on the first surgical navigation applied for epiduroscopic laser neural decompression procedure. PMID:26297136

  6. Empirical models for use in designing decompression procedures for space operations

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Edwards, Benjamin F.; Waligora, James M.; Horrigan, David J., Jr.

    1987-01-01

    Empirical models for predicting the incidence of Type 1 altitude decompression sickness (DCS) and venous gas emboli (VGE) during space extravehicular activity (EVA), and for use in designing safe denitrogenation decompression procedures are developed. The models are parameterized using DCS and VGE incidence data from NASA and USAF manned altitude chamber decompression tests using 607 male and female subject tests. These models, and procedures for their use, consist of: (1) an exponential relaxation model and procedure for computing tissue nitrogen partial pressure resulting from a specified prebreathing and stepped decompression sequence; (2) a formula for calculating Tissue Ratio (TR), a tissue decompression stress index; (3) linear and Hill equation models for predicting the total incidence of VGE and DCS attendant with a particular TR; (4) graphs of cumulative DCS and VGE incidence (risk) versus EVA exposure time at any specified TR; and (5) two equations for calculating the average delay period for the initial detection of VGE or indication of Type 1 DCS in a group after a specific denitrogenation decompression procedure. Several examples of realistic EVA preparations are provided.

  7. Anterior decompression and fusion versus posterior laminoplasty for multilevel cervical compressive myelopathy.

    PubMed

    Liu, Xuzhou; Wang, Hehui; Zhou, Zhilai; Jin, Anmin

    2014-02-01

    The optimal surgical strategy for anterior or posterior approaches remains controversial for multilevel cervical compressive myelopathy caused by multisegment cervical spondylotic myelopathy (MCSM) or ossification of the posterior longitudinal ligament (OPLL). A systematic review and meta-analysis was conducted evaluating the clinical results of anterior decompression and fusion (ADF) compared with posterior laminoplasty for patients with multilevel cervical compressive myelopathy. PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials and nonrandomized cohort studies conducted from 1990 to May 2013 comparing ADF with posterior laminoplasty for the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL. The following outcome measures were extracted: Japanese Orthopedic Association (JOA) score, recovery rate, complication rate, reoperation rate, blood loss, and operative time. Subgroup analysis was conducted according to the mean number of surgical segments. Eleven studies were included in the review, all of which were prospective or retrospective cohort studies with relatively low quality indicated by GRADE Working Group assessment. A definitive conclusion could not be reached regarding which surgical approach is more effective for the treatment of multilevel cervical compressive myelopathy. Although ADF was associated with better postoperative neural function than posterior laminoplasty in the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL, there was no apparent difference in the neural function recovery rate between the 2 approaches. Higher rates of surgery-related complication and reoperation should be taken into consideration when ADF is used for patients with multilevel cervical compressive myelopathy. The surgical trauma associated with corpectomy was significantly higher than that associated with posterior laminoplasty. PMID:24679196

  8. Development of a finite element model of decompressive craniectomy.

    PubMed

    Fletcher, Tim L; Kolias, Angelos G; Hutchinson, Peter J A; Sutcliffe, Michael P F

    2014-01-01

    Decompressive craniectomy (DC), an operation whereby part of the skull is removed, is used in the management of patients with brain swelling. While the aim of DC is to reduce intracranial pressure, there is the risk that brain deformation and mechanical strain associated with the operation could damage the brain tissue. The nature and extent of the resulting strain regime is poorly understood at present. Finite element (FE) models of DC can provide insight into this applied strain and hence assist in deciding on the best surgical procedures. However there is uncertainty about how well these models match experimental data, which are difficult to obtain clinically. Hence there is a need to validate any modelling approach outside the clinical setting. This paper develops an axisymmetric FE model of an idealised DC to assess the key features of such an FE model which are needed for an accurate simulation of DC. The FE models are compared with an experimental model using gelatin hydrogel, which has similar poro-viscoelastic material property characteristics to brain tissue. Strain on a central plane of the FE model and the front face of the experimental model, deformation and load relaxation curves are compared between experiment and FE. Results show good agreement between the FE and experimental models, providing confidence in applying the proposed FE modelling approach to DC. Such a model should use material properties appropriate for brain tissue and include a more realistic whole head geometry. PMID:25025666

  9. Development of a Finite Element Model of Decompressive Craniectomy

    PubMed Central

    Fletcher, Tim L.; Kolias, Angelos G.; Hutchinson, Peter J. A.; Sutcliffe, Michael P. F.

    2014-01-01

    Decompressive craniectomy (DC), an operation whereby part of the skull is removed, is used in the management of patients with brain swelling. While the aim of DC is to reduce intracranial pressure, there is the risk that brain deformation and mechanical strain associated with the operation could damage the brain tissue. The nature and extent of the resulting strain regime is poorly understood at present. Finite element (FE) models of DC can provide insight into this applied strain and hence assist in deciding on the best surgical procedures. However there is uncertainty about how well these models match experimental data, which are difficult to obtain clinically. Hence there is a need to validate any modelling approach outside the clinical setting. This paper develops an axisymmetric FE model of an idealised DC to assess the key features of such an FE model which are needed for an accurate simulation of DC. The FE models are compared with an experimental model using gelatin hydrogel, which has similar poro-viscoelastic material property characteristics to brain tissue. Strain on a central plane of the FE model and the front face of the experimental model, deformation and load relaxation curves are compared between experiment and FE. Results show good agreement between the FE and experimental models, providing confidence in applying the proposed FE modelling approach to DC. Such a model should use material properties appropriate for brain tissue and include a more realistic whole head geometry. PMID:25025666

  10. Ocular Decompression Retinopathy Following Canaloplasty for Primary Open Angle Glaucoma

    PubMed Central

    Li, Gai-yun; Alantaree, Samer; Wang, Jun-ming; Zhang, Hong

    2016-01-01

    Abstract Ocular decompression retinopathy (ODR), a rare postoperative complication following glaucoma surgery, is characterized by the transient appearance of scattered retinal hemorrhages. Here, we present a unique case of ODR in a patient with primary open angle glaucoma who underwent canaloplasty. A 31-year-old male patient presented with an intraocular pressure (IOP) of 60 mm Hg in the right eye. The IOP remained over 40 mm Hg, even when treated with maximum tolerated antiglaucoma medication. Canaloplasty drastically lowered IOP in the right eye from 40 to 7 mm Hg. However, fundus examination revealed ODR after surgery. The patient was treated with tobramycin and dexamethasone. Three months after canaloplasty, IOP remained in control at 16 mm Hg and all retinal hemorrhages had completely resolved. This case demonstrates that ODR can occur following canaloplasty and physicians should be aware of this potential complication in patients with severely elevated IOP. Sufficiently lowering IOP before surgery and gradually decreasing IOP during surgery may prevent ODR from occurring. PMID:26945386

  11. Decompressive craniectomy for arteriovenous malformation-related intracerebral hemorrhage.

    PubMed

    Takeuchi, Satoru; Takasato, Yoshio; Masaoka, Hiroyuki; Nagatani, Kimihiro; Otani, Naoki; Wada, Kojiro; Mori, Kentaro

    2015-03-01

    Arteriovenous malformation (AVM)-related intracerebral hemorrhage (ICH) is the cause of approximately 2-3% of ICH and is an important factor in the significant morbidity and mortality in patients with AVM. Decompressive craniectomy (DC) is a surgical procedure to relieve malignant elevation of intracranial pressure. The use of DC to treat patients with AVM-ICH has been much less common. The present study describes our experience with DC for AVM-ICH and discusses the safety of this procedure. The present retrospective analysis compared 12 consecutive patients treated with DC for AVM-ICH with 23 patients treated with DC for hypertensive ICH. Nine patients were male and three were female, aged from 11 to 53 years (mean, 31.7 years). Hematoma volumes ranged from 50 to 106 ml (mean, 75.8 ml). The outcomes were good recovery in one patient, moderate disability in three, severe disability in seven, and vegetative state in one. Complications after DC included subdural hygroma in four patients, hydrocephalus in one, intracranial infection in two, and intracranial hemorrhage in one. No significant difference was found in the incidence of complications between DC for large AVM-ICH and DC for hypertensive ICH. In conclusion, the present study found no significant difference in the incidence of complications between DC for large AVM-ICH and DC for hypertensive ICH. Further investigations including a prospective randomized trial are needed to confirm the safety and efficacy of DC for the treatment of large AVM-ICH. PMID:25564272

  12. Gastric Decompression Decreases Postoperative Nausea and Vomiting in ENT Surgery

    PubMed Central

    Erkalp, Kerem; Kalekoglu Erkalp, Nuran; Sevdi, M. Salih; Korkut, A. Yasemin; Yeter, Hacer; Ege, Sertuğ Sinan; Alagol, Aysin

    2014-01-01

    There is a passive blood flow to the stomach during oral and nasal surgery. It may cause postoperative nausea and vomiting (PONV). We researched the relationship between gastric decompression (GD) and severity of PONV in ear, nose, and throat (ENT) surgery. 137 patients who have been into ENT surgery were included in the study. In Group I (n = 70), patients received GD after surgery before extubation; patients in Group II (n = 67) did not receive GD. In postoperative 2nd, 4th, 8th, and 12th hours, the number and ratio of patients demonstrating PONV were detected to be significantly more in Group II as compared to Group I. PONV was also significantly more severe in Group II as compared to Group I. In Group I, the PONV ratio in the 2nd hour was significantly more for those whose amounts of stomach content aspired were more than 10 mL as compared to those whose stomach content aspired was less than 10 mL. In the 4th, 8th, and 24th hours, there is no statistically significant difference between the stomach content aspired and PONV ratio. GD reduces the incidence and severity of PONV in ENT surgery. PMID:24803935

  13. Decompressive craniectomy following traumatic brain injury: developing the evidence base.

    PubMed

    Kolias, Angelos G; Adams, Hadie; Timofeev, Ivan; Czosnyka, Marek; Corteen, Elizabeth A; Pickard, John D; Turner, Carole; Gregson, Barbara A; Kirkpatrick, Peter J; Murray, Gordon D; Menon, David K; Hutchinson, Peter J

    2016-04-01

    In the context of traumatic brain injury (TBI), decompressive craniectomy (DC) is used as part of tiered therapeutic protocols for patients with intracranial hypertension (secondary or protocol-driven DC). In addition, the bone flap can be left out when evacuating a mass lesion, usually an acute subdural haematoma (ASDH), in the acute phase (primary DC). Even though, the principle of "opening the skull" in order to control brain oedema and raised intracranial pressure has been practised since the beginning of the 20th century, the last 20 years have been marked by efforts to develop the evidence base with the conduct of randomised trials. This article discusses the merits and challenges of this approach and provides an overview of randomised trials of DC following TBI. An update on the RESCUEicp study, a randomised trial of DC versus advanced medical management (including barbiturates) for severe and refractory post-traumatic intracranial hypertension is provided. In addition, the rationale for the RESCUE-ASDH study, the first randomised trial of primary DC versus craniotomy for adult head-injured patients with an ASDH, is presented. PMID:26972805

  14. Complications Associated with Decompressive Craniectomy: A Systematic Review

    PubMed Central

    Kurland, David B.; Khaladj-Ghom, Ariana; Stokum, Jesse A.; Carusillo, Brianna; Karimy, Jason K.; Gerzanich, Volodymyr; Sahuquillo, Juan

    2015-01-01

    Decompressive craniectomy (DC) has been used for many years in the management of patients with elevated intracranial pressure and cerebral edema. Ongoing clinical trials are investigating the clinical and cost effectiveness of DC in trauma and stroke. While DC has demonstrable efficacy in saving life, it is accompanied by a myriad of non-trivial complications that have been inadequately highlighted in prospective clinical trials. Missing from our current understanding is a comprehensive analysis of all potential complications associated with DC. Here, we review the available literature, we tabulate all reported complications, and we calculate their frequency for specific indications. Of over 1500 records initially identified, a final total of 142 eligible records were included in our comprehensive analysis. We identified numerous complications related to DC that have not been systematically reviewed. Complications were of three major types: (1) Hemorrhagic (2) Infectious/Inflammatory, and (3) Disturbances of the CSF compartment. Complications associated with cranioplasty fell under similar major types, with additional complications relating to the boneflap. Overall, one of every ten patients undergoing DC may suffer a complication necessitating additional medical and/or neurosurgical intervention. While DC has received increased attention as a potential therapeutic option in a variety of situations, like any surgical procedure, DC is not without risk. Neurologists and neurosurgeons must be aware of all the potential complications of DC in order to properly advise their patients. PMID:26032808

  15. Early decompressive craniectomy for neurotrauma: an institutional experience

    PubMed Central

    Rubiano, Andrès Mariano; Villarreal, Wilson; Hakim, Enrique Jimenez; Aristizabal, Jorge; Hakim, Fernando; Dìez, Juan Carlos; Peña, Germàn; Puyana, Juan Carlos

    2010-01-01

    Background Neurotrauma centers have developed management protocols on the basis of evidence obtained from literature analysis and institutional experience. This article reviews our institutional experience in the management of severe traumatic brain injury (TBI) at Simòn Bolivar Hospital, the district trauma center for Bogotá's north zone. Methods This is a case control study comparing a group of patients (n: 16) operated for severe TBI between January 2002 and July 2004 according to an institutional management protocol characterized by an early decompressive craniectomy (DC) approach versus a historical control group (n: 20) managed before the implementation of such protocol. Mortality and Glasgow Outcome Score (GOS) at 6 months were used as the main outcome variables. Results An early DC protocol implemented within 12 hours from injury in 16 patients with severe isolated TBI and a Marshall score between III or IV was associated with a lesser mortality than the conventional approach with ventriculostomy and Intensive Care Unit (ICU) management alone. The GOS was significantly better in the DC group (p=0.0002) than in the control group. Conclusion The use of an early DC protocol for severe TBI patients (Glasgow Coma Scale <9) had a significantly improved outcome compared with the conventional approach with ventriculostomy and ICU management in Simòn Bolivar Hospital in Bogotá, Colombia. PMID:19130336

  16. Image compression and decompression based on gazing area

    NASA Astrophysics Data System (ADS)

    Tsumura, Norimichi; Endo, Chizuko; Haneishi, Hideaki; Miyake, Yoichi

    1996-04-01

    In this paper, we introduce a new method of data compression and decompression technique to search the aimed image based on the gazing area of the image. Many methods of data compression have been proposed. Particularly, JPEG compression technique has been widely used as a standard method. However, this method is not always effective to search the aimed images from the image filing system. In a previous paper, by the eye movement analysis, we found that images have a particular gazing area. It is considered that the gazing area is the most important region of the image, then we considered introducing the information to compress and transmit the image. A method named fixation based progressive image transmission is introduced to transmit the image effectively. In this method, after the gazing area is estimated, the area is first transmitted and then the other regions are transmitted. If we are not interested in the first transmitted image, then we can search other images. Therefore, the aimed image can be searched from the filing system, effectively. We compare the searching time of the proposed method with the conventional method. The result shows that the proposed method is faster than the conventional one to search the aimed image.

  17. Window decompression in laser-heated MagLIF targets

    NASA Astrophysics Data System (ADS)

    Woodbury, Daniel; Peterson, Kyle; Sefkow, Adam

    2015-11-01

    The Magnetized Liner Inertial Fusion (MagLIF) concept requires pre-magnetized fuel to be pre-heated with a laser before undergoing compression by a thick solid liner. Recent experiments and simulations suggest that yield has been limited to date by poor laser preheat and laser-induced mix in the fuel region. In order to assess laser energy transmission through the pressure-holding window, as well as resultant mix, we modeled window disassembly under different conditions using 1D and 2D simulations in both Helios and HYDRA. We present results tracking energy absorption, time needed for decompression, risk of laser-plasma interaction (LPI) that may scatter laser light, and potential for mix from various window thicknesses, laser spot sizes and gas fill densities. These results indicate that using thinner windows (0.5-1 μm windows) and relatively large laser spot radii (600 μm and above) can avoid deleterious effects and improve coupling with the fuel. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under DE-AC04- 94AL85000.

  18. MR guidance of laser disc decompression: preliminary in vivo experience.

    PubMed

    Steiner, P; Zweifel, K; Botnar, R; Schoenenberger, A W; Debatin, J F; von Schulthess, G K; Hodler, J

    1998-01-01

    The purpose of this study was to perform percutaneous laser disc decompression (PLDD) under MR guidance in an open configuration 0. 5-T MR system. Following failed conservative treatment for 6 months, eight patients with contained disc herniations were enrolled in the study. Following MR guided introduction of the laser fiber into the targeted disc space, the laser-induced temperature distribution was visualized using a color-coded subtraction technique based on a T1-weighted GRE sequence. In seven patients PLDD could be performed. In all cases laser effects were depicted by MR. In this regard the color-coded technique was found to be superior to conventional magnitude images. Whereas no apparent decrease in the extent of herniation was discovered immediately following PLDD, T2-weighted FSE images showed signal intensity alterations in two of the seven patients. Clinical evaluation, obtained 3-4 months after PLDD, revealed a fair (n = 2) or good (n = 4) response to the treatment. One patient showed no change in symptoms. MR guidance and monitoring of PLDD is feasible within an open 0.5-T system and seems to render PLDD more safe and controllable. PMID:9569329

  19. Radiological considerations: patient selection for percutaneous laser disc decompression.

    PubMed

    Botsford, J A

    1994-10-01

    Percutaneous laser disc decompression (PLDD) is an effective method of treating the lumbar herniated nucleus pulposis (HNP) that is both contained by the annular/posterior longitudinal ligament (PLL) complex and connected to the parent disc of origin. Not all radiological studies have the same ability to diagnose this specific type of herniation and therefore are not equally useful in the preoperative evaluation of the PLDD candidate. Ninety PLDD treated patients were retrospectively reviewed to determine which of the four most commonly performed lumbar imaging exams, when abnormal, correlated with a successful outcome. Overall MacNab criteria improvement occurred in 73.3% of PLDD-treated patients. An abnormal CT discogram correlated with PLDD success in all patients treated (100%). An abnormal MRI, CT, or myelogram correlated with success in 75% or less of patients treated. The theoretical reasons for the superiority of CT discography are discussed and the diagnostic potential of all major lumbar imaging modalities is reviewed. A diagnostic decision scheme for the evaluation of the prospective PLDD patient is presented. PMID:10150671

  20. Decompressive craniectomy following traumatic brain injury: developing the evidence base

    PubMed Central

    Kolias, Angelos G.; Adams, Hadie; Timofeev, Ivan; Czosnyka, Marek; Corteen, Elizabeth A.; Pickard, John D.; Turner, Carole; Gregson, Barbara A.; Kirkpatrick, Peter J.; Murray, Gordon D.; Menon, David K.; Hutchinson, Peter J.

    2016-01-01

    Abstract In the context of traumatic brain injury (TBI), decompressive craniectomy (DC) is used as part of tiered therapeutic protocols for patients with intracranial hypertension (secondary or protocol-driven DC). In addition, the bone flap can be left out when evacuating a mass lesion, usually an acute subdural haematoma (ASDH), in the acute phase (primary DC). Even though, the principle of “opening the skull” in order to control brain oedema and raised intracranial pressure has been practised since the beginning of the 20th century, the last 20 years have been marked by efforts to develop the evidence base with the conduct of randomised trials. This article discusses the merits and challenges of this approach and provides an overview of randomised trials of DC following TBI. An update on the RESCUEicp study, a randomised trial of DC versus advanced medical management (including barbiturates) for severe and refractory post-traumatic intracranial hypertension is provided. In addition, the rationale for the RESCUE-ASDH study, the first randomised trial of primary DC versus craniotomy for adult head-injured patients with an ASDH, is presented. PMID:26972805

  1. Survivorship models for estimating the risk of decompression sickness.

    PubMed

    Kumar, K V; Powell, M R

    1994-07-01

    Several approaches have been used for modeling the incidence of decompression sickness (DCS) such as Hill's dose-response and logistic regression. Most of these methods do not include the time-to-onset information in the model. Survival analysis (failure time analysis) is appropriate when the time to onset of an event is of interest. The applicability of survival analysis for modeling the risk of DCS is illustrated by using data obtained from hypobaric chamber exposures simulating extravehicular activities (n = 426). Univariate analysis of incidence-free survival proportions were obtained for Doppler-detectable circulating microbubbles (CMB), symptoms of DCS and test aborts. A log-linear failure time regression model with 360-min half-time tissue ratio (TR) as covariate was constructed, and estimated probabilities for various TR values were calculated. Further regression analysis by including CMB status in this model showed significant improvement (p < 0.05) in the estimation of DCS over the previous model. Since DCS is dependent on the exposure pressure as well as the duration of exposure, we recommend the use of survival analysis for modeling the risk of DCS. PMID:7945136

  2. Factors prognosticating the outcome of decompressive craniectomy in severe traumatic brain injury: A Malaysian experience

    PubMed Central

    Sharda, Priya; Haspani, Saffari; Idris, Zamzuri

    2014-01-01

    Objective: The objective of this prospective cohort study was to analyse the characteristics of severe Traumatic Brain Injury (TBI) in a regional trauma centre Hospital Kuala Lumpur (HKL) along with its impact of various prognostic factors post Decompressive Craniectomy (DC). Materials and Methods: Duration of the study was of 13 months in HKL. 110 consecutive patients undergoing DC and remained in our centre were recruited. They were then analysed categorically with standard analytical software. Results: Age group have highest range between 12-30 category with male preponderance. Common mechanism of injury was motor vehicle accident involving motorcyclist. Univariate analysis showed statistically significant in referral area (P = 0.006). In clinical evaluation statistically significant was the motor score (P = 0.040), pupillary state (P = 0.010), blood pressure stability (P = 0.013) and evidence of Diabetes Insipidus (P < 0.001). In biochemical status the significant statistics included evidence of coagulopathy (P < 0.001), evidence of acidosis (P = 0.003) and evidence of hypoxia (P = 0.030). In Radiological sector, significant univariate analysis proved in location of the subdural clot (P < 0.010), location of the contusion (P = 0.045), site of existence of both type of clots (P = 0.031) and the evidence of edema (P = 0.041). The timing of injury was noted to be significant as well (P = 0.061). In the post operative care was, there were significance in the overall stability in intensive care (P < 0.001), the stability of blood pressure, cerebral perfusion pressure, pulse rates and oxygen saturation (all P < 0.001)seen individually, post operative ICP monitoring in the immediate (P = 0.002), within 24 hours (P < 0.001) and within 24-48 hours (P < 0.001) period, along with post operative pupillary size (P < 0.001) and motor score (P < 0.001). Post operatively, radiologically significant statistics included evidence of midline shift post operatively in the CT scan

  3. Decompression sickness and aseptic necrosis of bone: Investigations carried out during and after the construction of the Tyne Road Tunnel (1962-66)

    PubMed Central

    1971-01-01

    Report of Decompression Sickness Panel, Medical Research Council (1971). Brit. J. industr. Med., 28, 1-21. Decompression sickness and aseptic necrosis of bone: Investigations carried out during and after the construction of the Tyne Road Tunnel (1962-66). This paper describes investigations into the health of compressed air workers during and after the construction of a road tunnel under the River Tyne. Altogether 641 men were exposed to the compressed air environment over a period of approximately 31 months. The maximum working pressure was 42 psig (289·6 kN/m2), and the overall decompression sickness rate for work at pressures of 18 psig (124·1 kN/m2) and above was 2%. Radiological examination of the chest was carried out on 183 men to detect lung cysts but only one was found. Thus lung cysts were not shown to be a common factor in the causation of decompression sickness but the possibility of small sub-radiological collections of trapped air being involved was not excluded. Radiological examinations of the shoulders, hips and knee joints were carried out on 171 men. There was evidence of aseptic necrosis in one or more bones of 44 men (26%). Fifteen of the men with definite lesions of aseptic necrosis of bone and 7 of the men with suspected lesions had never worked in compressed air before this contract. The remaining 14 men with definite lesions and the 8 with suspected lesions had worked elsewhere in compressed air prior to this contract, but a definite lesion in one of these men and a suspected lesion in another can almost certainly be attributed to their work in compressed air on this contract. Images PMID:5543625

  4. The r-process nucleosynthesis during the decompression of neutron star crust material

    NASA Astrophysics Data System (ADS)

    Goriely, S.; Bauswein, A.; Janka, H.-T.; Sida, J.-L.; Lemaître, J.-F.; Panebianco, S.; Dubray, N.; Hilaire, S.

    2014-05-01

    About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

  5. The r-process nucleosynthesis during the decompression of neutron star crust material

    NASA Astrophysics Data System (ADS)

    Goriely, S.; Bauswein, A.; Janka, H.-T.; Panebianco, S.; Sida, J.-L.; Lemaître, J.-F.; Hilaire, S.; Dubray, N.

    2016-01-01

    About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

  6. Online remote control systems for static and dynamic compression and decompression using diamond anvil cells

    SciTech Connect

    Sinogeikin, Stanislav V. Smith, Jesse S.; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

    2015-07-15

    The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research.

  7. Out-of-Core Compression and Decompression of Large n-Dimensional Scalar Fields

    SciTech Connect

    Ibarria, L; Lindstrom, P; Rossignac, J; Szymczak, A

    2003-05-07

    We present a simple method for compressing very large and regularly sampled scalar fields. Our method is particularly attractive when the entire data set does not fit in memory and when the sampling rate is high relative to the feature size of the scalar field in all dimensions. Although we report results for R{sup 3} and R{sup 4} data sets, the proposed approach may be applied to higher dimensions. The method is based on the new Lorenzo predictor, introduced here, which estimates the value of the scalar field at each sample from the values at processed neighbors. The predicted values are exact when the n-dimensional scalar field is an implicit polynomial of degree n-1. Surprisingly, when the residuals (differences between the actual and predicted values) are encoded using arithmetic coding, the proposed method often outperforms wavelet compression in an L{infinity} sense. The proposed approach may be used both for lossy and lossless compression and is well suited for out-of-core compression and decompression, because a trivial implementation, which sweeps through the data set reading it once, requires maintaining only a small buffer in core memory, whose size barely exceeds a single n-1 dimensional slice of the data.

  8. The r-process nucleosynthesis during the decompression of neutron star crust material

    SciTech Connect

    Goriely, S.; Bauswein, A.; Janka, H.-T.; Sida, J.-L.; Lemaître, J.-F.; Panebianco, S.

    2014-05-02

    About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

  9. Current neurosurgical management of glossopharyngeal neuralgia and technical nuances for microvascular decompression surgery.

    PubMed

    Rey-Dios, Roberto; Cohen-Gadol, Aaron A

    2013-03-01

    Glossopharyngeal neuralgia (GPN) is an uncommon facial pain syndrome often misdiagnosed as trigeminal neuralgia. The rarity of this condition and its overlap with other cranial nerve hyperactivity syndromes often leads to a significant delay in diagnosis. The surgical procedures with the highest rates of pain relief for GPN are rhizotomy and microvascular decompression (MVD) of cranial nerves IX and X. Neurovascular conflict at the level of the root exit zone of these cranial nerves is believed to be the cause of this pain syndrome in most cases. Vagus nerve rhizotomy is usually reserved for cases in which vascular conflict is not evident. A review of the literature reveals that although the addition of cranial nerve X rhizotomy may improve the chances of long-term pain control, this maneuver also increases the risk of permanent dysphagia and vocal cord paralysis. The risks of this procedure have to be carefully weighed against its benefits. Based on the authors' experience, careful patient selection with a thorough exploratory operation most often leads to identification of the site of vascular conflict, obviating the need for cranial nerve X rhizotomy. PMID:23451790

  10. The comparison of the efficacy of radiofrequency nucleoplasty and targeted disc decompression in lumbar radiculopathy

    PubMed Central

    Adakli, Barıs; Turhan, K. Sanem Cakar; Asik, Ibrahim

    2015-01-01

    Chronic low back pain is a common clinical condition causing medical, socioeconomic, and treatment difficulties. In our study, we aimed to compare early and long-term efficacy of lumbar radiofrequency thermocoagulation (RFTC) nucleoplasty and targeted disc decompression (TDD) in patients with lumbar radiculopathy in whom previous conventional therapy had failed. The medical records of 37 patients undergoing TDD and 36 patients undergoing lumbar RFTC nucleoplasty were retrospectively examined and assigned to the Group D and Group N, respectively. In all patients Visual Analogue Scale (VAS) and Functional Rating Index (FRI) were recorded before treatment and after one, six and twelve months after the procedure. The North American Spine Society Satisfaction Scale (NASSSS) was also recoreded twelve months after the therapeutic procedure. Statistically significant postprocedural improvement in VAS and FRI was evident in both groups. VAS scores after one, six, and twelve month were slightly higher in Group N, compared to Group D. The overall procedure-related patient satisfaction ratio was 67.5% in the Group D, compared to 75% in the Group N. Regardless of the different mechanism of action, both methods are effective therapies for lumbar radiculopathy, with TDD showing long-term lower pain scores. PMID:26042514

  11. Online remote control systems for static and dynamic compression and decompression using diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Sinogeikin, Stanislav V.; Smith, Jesse S.; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

    2015-07-01

    The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research.

  12. The use of straw mulch as a strategy to prevent extreme soil erosion rates in citrus orchard. A Rainfall simulation approach

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Giménez-Morera, Antonio; Jordán, Antonio; Pereira, Paulo; Novara, Agata; García-Orenes, Fuensanta

    2014-05-01

    Not only the Sahel (Haregeweyn et al., 2013), the deforested land (Borelli et al., 2013) the chinese Plateau are affected by intense soil erosion rates (Zhao et al., 2013). Soil erosion affect agriculture land (Cerdà et al., 2009), and citrus orchards are being seeing as one of the crops with the highest erosion rates due to the managements that avoid the catch crops, weeds or litter. Example of the research carried out on citrus orchards is found in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) and in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012), and they confirm the non sustainable soil losses measured. The land management in citrus plantations results in soil degradation too (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012). The use of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel has been found successful. There is a need to find new plants or residues to protect the soils on citrus orchards. Agriculture produces a high amount of residues. The pruning can contribute with a valuable source of nutrients and a good soil protection. The leaves of the trees, and some parts of the plants, once harvest can contribute to reduce the soil losses. Due to the mechanization of the agriculture, and the reduction of the draft animals (mainly horses, mules, donkeys and oxen) the straw is being a residue instead of a resource. The Valencia region is the largest producer of citrus in Europe, and the largest exporter in the world. This citrus production region is located in the eastern cost of Spain where we can find the rice production area of the l'Albufera Lagoon paddy fields, the third largest production region in Spain. This means, a rice production region surrounded by the huge citrus production region. There, the rice straw is not used

  13. Decompression Device Using a Stainless Steel Tube and Wire for Treatment of Odontogenic Cystic Lesions: A Technical Report

    PubMed Central

    Jung, Eun-Joo; Baek, Jin-A; Leem, Dae-Ho

    2014-01-01

    Decompression is considered an effective treatment for odontogenic cystic lesions in the jaw. A variety of decompression devices are successfully used for the treatment of keratocystic odontogenic tumors, radicular cysts, dentigerous cysts, and ameloblastoma. The purpose of these devices is to keep an opening between the cystic lesion and the oral environment during treatment. The aim of this report is to describe an effective decompression tube using a stainless steel tube and wire for treatment of jaw cystic lesions. PMID:27489852

  14. Role of Coflex as an Adjunct to Decompression for Symptomatic Lumbar Spinal Stenosis

    PubMed Central

    Shah, Siddarth M; Ng, Yau Hong; Pannierselvam, Vinodh Kumar; DasDe, Sudeep; Shen, Liang

    2014-01-01

    Study Design Prospective cohort study. Purpose To assess whether additional implantation of Coflex following spinal decompression provided better clinical outcomes compared to decompression alone for symptomatic lumbar spinal stenosis (LSS) and to determine whether improvement in clinical outcomes correlated with changes in the radiological indices studied. Overview of Literature Literature on benefits of additional Coflex implantation compared to decompression alone for symptomatic LSS is limited. Methods Patients with symptomatic LSS who met the study criteria were offered spinal decompression with Coflex implantation. Those patients who accepted Coflex implantation were placed in the Coflex group (n=22); while those opting for decompression alone, were placed in the comparison group (n=24). Clinical outcomes were assessed preoperatively, six-months, one-year and two-years postoperatively, using the Oswestry disability index, 100 mm visual analogue scale (VAS)-back pain and VAS-leg pain, and short form-36 (SF-36). Radiological indices (disc height, foraminal height and sagittal angle) were assessed preoperatively, six months, one year, and two years postoperatively. Results Both groups showed statistically significant (p<0.001) improvement in all the clinical outcome indicators at all points in time as compared to the preoperative status. However, improvement in the Coflex group was significantly greater (p<0.001) than the comparison group. Changes in the radiological indices did not correlate significantly with the improvement in clinical outcome indicators. Conclusions Additional Coflex implantation after spinal decompression in symptomatic LSS offers better clinical outcomes than decompression alone in the short-term. Changes in radiological indices do not correlate with the improvements in clinical outcomes after surgery for symptomatic LSS. PMID:24761198

  15. MRI Evaluation of Post Core Decompression Changes in Avascular Necrosis of Hip

    PubMed Central

    Marupaka, Sravan Kumar; Alluri, Swathi; MD, Naseeruddin; Irfan, Kazi Amir; Jampala, Venkateshwarlu; Apsingi, Sunil; Eachempati, Krishna Kiran

    2015-01-01

    Introduction Avascular necrosis of hip typically presents in young patients. Core decompression in precollapse stage provides pain relief and preservation of femoral head. The results of core decompression vary considerably despite early diagnosis. The role of MRI in monitoring patients post surgically has not been clearly defined. Aim To study pre and post core decompression MRI changes in avascular necrosis of hip. Materials and Methods This is a contiguous observational cohort of 40 hips treated by core decompression for precollapse avascular necrosis of femoral head, who had a baseline MRI performed before surgery. Core decompression of the femoral head was performed within 4 weeks. Follow up radiograph and MRI scans were done at six months. Harris hip score preoperatively, 1 month and 6 months after the surgery was noted. Success in this study was defined as postoperative increase in Harris hip score (HHS) by 20 points and no additional femoral collapse. End point of clinical adverse outcome as defined by fall in Harris hip score was conversion or intention to convert to total hip replacement (THR). MRI parameters in the follow up scan were compared to the preoperative MRI. Effect of core decompression on bone marrow oedema and femoral head collapse was noted. Results were analysed using SPSS software version. Results Harris hip score improved from 57 to 80 in all patients initially. Six hips had a fall in Harris hip score to mean value of 34.1 during follow up (9 to 12 months) and underwent total hip replacement. MRI predictors of positive outcome are lesions with grade A extent, Grade A & B location. Bone marrow oedema with lesions less than 50% involvement, medial and central location. Conclusion Careful selection of patients by MR criteria for core decompression provides satisfactory outcome in precollapse stage of avascular necrosis of hip. PMID:26816966

  16. Parameter estimation of the copernicus decompression model with venous gas emboli in human divers.

    PubMed

    Gutvik, Christian R; Dunford, Richard G; Dujic, Zeljko; Brubakk, Alf O

    2010-07-01

    Decompression Sickness (DCS) may occur when divers decompress from a hyperbaric environment. To prevent this, decompression procedures are used to get safely back to the surface. The models whose procedures are calculated from, are traditionally validated using clinical symptoms as an endpoint. However, DCS is an uncommon phenomenon and the wide variation in individual response to decompression stress is poorly understood. And generally, using clinical examination alone for validation is disadvantageous from a modeling perspective. Currently, the only objective and quantitative measure of decompression stress is Venous Gas Emboli (VGE), measured by either ultrasonic imaging or Doppler. VGE has been shown to be statistically correlated with DCS, and is now widely used in science to evaluate decompression stress from a dive. Until recently no mathematical model has existed to predict VGE from a dive, which motivated the development of the Copernicus model. The present article compiles a selection experimental dives and field data containing computer recorded depth profiles associated with ultrasound measurements of VGE. It describes a parameter estimation problem to fit the model with these data. A total of 185 square bounce dives from DCIEM, Canada, 188 recreational dives with a mix of single, repetitive and multi-day exposures from DAN USA and 84 experimentally designed decompression dives from Split Croatia were used, giving a total of 457 dives. Five selected parameters in the Copernicus bubble model were assigned for estimation and a non-linear optimization problem was formalized with a weighted least square cost function. A bias factor to the DCIEM chamber dives was also included. A Quasi-Newton algorithm (BFGS) from the TOMLAB numerical package solved the problem which was proved to be convex. With the parameter set presented in this article, Copernicus can be implemented in any programming language to estimate VGE from an air dive. PMID:20414813

  17. The use of straw mulch as a strategy to prevent extreme soil erosion rates in citrus orchard. A Rainfall simulation approach

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Giménez-Morera, Antonio; Jordán, Antonio; Pereira, Paulo; Novara, Agata; García-Orenes, Fuensanta

    2014-05-01

    Not only the Sahel (Haregeweyn et al., 2013), the deforested land (Borelli et al., 2013) the chinese Plateau are affected by intense soil erosion rates (Zhao et al., 2013). Soil erosion affect agriculture land (Cerdà et al., 2009), and citrus orchards are being seeing as one of the crops with the highest erosion rates due to the managements that avoid the catch crops, weeds or litter. Example of the research carried out on citrus orchards is found in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) and in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012), and they confirm the non sustainable soil losses measured. The land management in citrus plantations results in soil degradation too (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012). The use of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel has been found successful. There is a need to find new plants or residues to protect the soils on citrus orchards. Agriculture produces a high amount of residues. The pruning can contribute with a valuable source of nutrients and a good soil protection. The leaves of the trees, and some parts of the plants, once harvest can contribute to reduce the soil losses. Due to the mechanization of the agriculture, and the reduction of the draft animals (mainly horses, mules, donkeys and oxen) the straw is being a residue instead of a resource. The Valencia region is the largest producer of citrus in Europe, and the largest exporter in the world. This citrus production region is located in the eastern cost of Spain where we can find the rice production area of the l'Albufera Lagoon paddy fields, the third largest production region in Spain. This means, a rice production region surrounded by the huge citrus production region. There, the rice straw is not used

  18. Direct Observations Of Microbial Activity At Extreme Pressures

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Scott, J. H.; Cody, G. D.; Fogel, M.; Hazen, R. M.; Hemley, R. J.; Huntress, W. T.

    2002-12-01

    Microbial communities adapt to a wide range of pressures, temperatures, salinities, pH, and oxidation states. Although, significant attention has been focused on the effects of high and low temperature on physiology, there is some evidence that elevated pressure may also manifest interesting effects on cellular physiology, such as enzyme inactivation, cell-membrane breach, and suppression of protein interactions with various substrates. However, exactly how these factors affect intact cells is not well understood. In this study, we have adapted diamond anvil cells to explore the effects of high pressure on microbial life. We used the rate of microbial formate oxidation as a probe of metabolic viability. The utilization of formate by microorganisms is a fundamental metabolic process in anaerobic environments. We monitored in-situ microbial formate oxidation via molecular spectroscopy for Shewanella oneidensis strain MR1 and Escherichia coli strain MG1655 at high pressures (68 to 1060 MPa). At pressures of 1200 to 1600 MPa, living bacteria resided in fluid inclusions in ice-VI crystals and continued to be viable upon subsequent release to ambient pressures (0.1 MPa). Furthermore, direct microscopic observations indicate that these cells maintain their ability for cellular division upon decompression from such high pressures. Evidence of microbial viability and activity at these extreme pressures expands by an order of magnitude the range of conditions representing the habitable zone in the solar system. These results imply that pressure may not be a significant impediment to life. The maximum pressure explored in this work is equivalent to a depth of ~ 50 km below Earth's crust, or ~ 160 km in a hypothetical ocean. The pressures encountered at the depths of thick ice caps and deep crustal subsurface may not be a limiting factor for the existence of life. This suggests that deep (water/ice) layers of Europa, Callisto, or Ganymede, subduction zones on Earth, and the

  19. The effect of simulated weightlessness on hypobaric decompression sickness

    NASA Technical Reports Server (NTRS)

    Balldin, Ulf I.; Pilmanis, Andrew A.; Webb, James T.

    2002-01-01

    BACKGROUND: A discrepancy exists between the incidence of ground-based decompression sickness (DCS) during simulated extravehicular activity (EVA) at hypobaric space suit pressure (20-40%) and crewmember reports during actual EVA (zero reports). This could be due to the effect of gravity during ground-based DCS studies. HYPOTHESIS: At EVA suit pressures of 29.6 kPa (4.3 psia), there is no difference in the incidence of hypobaric DCS between a control group and group exposed to simulated weightlessness (supine body position). METHODS: Male subjects were exposed to a hypobaric pressure of 29.6 kPa (4.3 psi) for up to 4 h. The control group (n = 26) pre-oxygenated for 60 min (first 10 min exercising) before hypobaric exposure and walking around in the altitude chamber. The test group (n = 39) remained supine for a 3 h prior to and during the 60-min pre-oxygenation (also including exercise) and at hypobaric pressure. DCS symptoms and venous gas emboli (VGE) at hypobaric pressure were registered. RESULTS: DCS occurred in 42% in the control and in 44% in simulated weightlessness group (n.s.). The mean time for DCS to develop was 112 min (SD +/- 61) and 123 min (+/- 67), respectively. VGE occurred in 81% of the control group subjects and in 51% of the simulated weightlessness subjects (p = 0.02), while severe VGE occurred in 58% and 33%, respectively (p = 0.08). VGE started after 113 min (+/- 43) in the control and after 76 min (+/- 64) in the simulated weightlessness group. CONCLUSIONS: No difference in incidence of DCS was shown between control and simulated weightlessness conditions. VGE occurred more frequently during the control condition with bubble-releasing arm and leg movements.

  20. Association of microparticles and neutrophil activation with decompression sickness.

    PubMed

    Thom, Stephen R; Bennett, Michael; Banham, Neil D; Chin, Walter; Blake, Denise F; Rosen, Anders; Pollock, Neal W; Madden, Dennis; Barak, Otto; Marroni, Alessandro; Balestra, Costantino; Germonpre, Peter; Pieri, Massimo; Cialoni, Danilo; Le, Phi-Nga Jeannie; Logue, Christopher; Lambert, David; Hardy, Kevin R; Sward, Douglas; Yang, Ming; Bhopale, Veena B; Dujic, Zeljko

    2015-09-01

    Decompression sickness (DCS) is a systemic disorder, assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles (MPs)--vesicular structures with diameters of 0.1-1.0 μm--have been implicated, but data in human divers have been lacking. We hypothesized that the number of blood-borne, Annexin V-positive MPs and neutrophil activation, assessed as surface MPO staining, would differ between self-contained underwater breathing-apparatus divers suffering from DCS vs. asymptomatic divers. Blood was analyzed from 280 divers who had been exposed to maximum depths from 7 to 105 meters; 185 were control/asymptomatic divers, and 90 were diagnosed with DCS. Elevations of MPs and neutrophil activation occurred in all divers but normalized within 24 h in those who were asymptomatic. MPs, bearing the following proteins: CD66b, CD41, CD31, CD142, CD235, and von Willebrand factor, were between 2.4- and 11.7-fold higher in blood from divers with DCS vs. asymptomatic divers, matched for time of sample acquisition, maximum diving depth, and breathing gas. Multiple logistic regression analysis documented significant associations (P < 0.001) between DCS and MPs and for neutrophil MPO staining. Effect estimates were not altered by gender, body mass index, use of nonsteroidal anti-inflammatory agents, or emergency oxygen treatment and were modestly influenced by divers' age, choice of breathing gas during diving, maximum diving depth, and whether repetitive diving had been performed. There were no significant associations between DCS and number of MPs without surface proteins listed above. We conclude that MP production and neutrophil activation exhibit strong associations with DCS. PMID:26139218

  1. Cranioplasty after decompressive craniectomy: the effect of timing on postoperative complications.

    PubMed

    Schuss, Patrick; Vatter, Hartmut; Marquardt, Gerhard; Imöhl, Lioba; Ulrich, Christian T; Seifert, Volker; Güresir, Erdem

    2012-04-10

    Decompressive craniectomy (DC) due to intractably elevated intracranial pressure mandates later cranioplasty (CP). However, the optimal timing of CP remains controversial. We therefore analyzed our prospectively conducted database concerning the timing of CP and associated post-operative complications. From October 1999 to August 2011, 280 cranioplasty procedures were performed at the authors' institution. Patients were stratified into two groups according to the time from DC to cranioplasty (early, ≤2 months, and late, >2 months). Patient characteristics, timing of CP, and CP-related complications were analyzed. Overall CP was performed early in 19% and late in 81%. The overall complication rate was 16.4%. Complications after CP included epidural or subdural hematoma (6%), wound healing disturbance (5.7%), abscess (1.4%), hygroma (1.1%), cerebrospinal fluid fistula (1.1%), and other (1.1%). Patients who underwent early CP suffered significantly more often from complications compared to patients who underwent late CP (25.9% versus 14.2%; p=0.04). Patients with ventriculoperitoneal (VP) shunt had a significantly higher rate of complications after CP compared to patients without VP shunt (p=0.007). On multivariate analysis, early CP, the presence of a VP shunt, and intracerebral hemorrhage as underlying pathology for DC, were significant predictors of post-operative complications after CP. We provide detailed data on surgical timing and complications for cranioplasty after DC. The present data suggest that patients who undergo late CP might benefit from a lower complication rate. This might influence future surgical decision making regarding optimal timing of cranioplasty. PMID:22201297

  2. Effect of posterior decompression extent on biomechanical parameters of the spinal cord in cervical ossification of the posterior longitudinal ligament.

    PubMed

    Khuyagbaatar, Batbayar; Kim, Kyungsoo; Park, Won Man; Kim, Yoon Hyuk

    2016-06-01

    Ossification of the posterior longitudinal ligament is a common cause of the cervical myelopathy due to compression of the spinal cord. Patients with ossification of the posterior longitudinal ligament usually require the decompression surgery, and there is a need to better understand the optimal surgical extent with which sufficient decompression without excessive posterior shifting can be achieved. However, few quantitative studies have clarified this optimal extent for decompression of cervical ossification of the posterior longitudinal ligament. We used finite element modeling of the cervical spine and spinal cord to investigate the effect of posterior decompression extent for continuous-type cervical ossification of the posterior longitudinal ligament on changes in stress, strain, and posterior shifting that occur with three different surgical methods (laminectomy, laminoplasty, and hemilaminectomy). As posterior decompression extended, stress and strain in the spinal cord decreased and posterior shifting of the cord increased. The location of the decompression extent also influenced shifting. Laminectomy and laminoplasty were very similar in terms of decompression results, and both were superior to hemilaminectomy in all parameters tested. Decompression to the extents of C3-C6 and C3-C7 of laminectomy and laminoplasty could be considered sufficient with respect to decompression itself. Our findings provide fundamental information regarding the treatment of cervical ossification of the posterior longitudinal ligament and can be applied to patient-specific surgical planning. PMID:26951839

  3. Extremely fast increase in the organic loading rate during the co-digestion of rapeseed oil and sewage sludge in a CSTR--characterization of granules formed due to CaO addition to maintain process stability.

    PubMed

    Kasina, M; Kleyböcker, A; Michalik, M; Würdemann, H

    2015-01-01

    In a co-digestion system running with rapeseed oil and sewage sludge, an extremely fast increase in the organic loading rate was studied to develop a procedure to allow for flexible and demand-driven energy production. The over-acidification of the digestate was successfully prevented by calcium oxide dosage, which resulted in granule formation. Mineralogical analyses revealed that the granules were composed of insoluble salts of long chain fatty acids and calcium and had a porous structure. Long chain fatty acids and calcium formed the outer cover of granules and offered interfaces on the inside thereby enhancing the growth of biofilms. With granule size and age, the pore size increased and indicated degradation of granular interfaces. A stable biogas production up to the organic loading rate of 10.4 kg volatile solids m(-3) d(-1) was achieved although the hydrogen concentration was not favorable for propionic acid degradation. However, at higher organic loading rates, unbalanced granule formation and degradation were observed. Obviously, the adaption time for biofilm growth was too short to maintain the balance, thereby resulting in a low methane yield. PMID:26524448

  4. Derivation of Mortal Injury Metric for Studies of Rapid Decompression of Depth-Acclimated Physostomous Fish

    SciTech Connect

    McKinstry, Craig A.; Carlson, Thomas J.; Brown, Richard S.

    2007-11-05

    In 2005 the U.S. Army Corps of Engineers (USACE) began a study to investigate the response of hatchery and run-of-the-river (ROR) juvenile Chinook salmon to the effects of rapid decompression during passage through mainstem Federal Columbia River Power System (FCRPS) Kaplan turbines. In laboratory studies conducted by Pacific Northwest National Laboratory (PNNL) for USACE since 2005, juvenile fish have been exposed to rapid decompression in a barometric pressure chamber. An initial study considered the response of juvenile Chinook salmon bearing radio transmitters to rapid decompression resulting from exposure to a pressure time history simulating the worst case condition that might be experienced during passage through an operating turbine. The study in 2005 found that acclimation depth was a very important treatment factor that greatly influenced the significantly higher incidence of injury and mortality of rapidly decompressed Chinook salmon bearing radio telemetry devices. In 2006 we initiated a statistical investigation using data in hand into derivation of a new end-point measure for assessment of the physiological response of juvenile Chinook salmon to rapid decompression. Our goal was a measure that would more fully utilize both mortality and injury data while providing a better assessment of the most likely survival outcome for juvenile physostomous fish exposed to rapid decompression. The conclusion of the analysis process was to classify fish as mortally injured when any of the 8 injuries are present, regardless of whether the fish was last observed alive or not. The mortally injured classification has replaced mortality as the end point metric for our rapid decompression studies. The process described in this report is an example of how a data set may be analyzed to identify decision criterion for objective classification of test fish to a specific end-point. The resulting list of 8 mortal injuries is applicable to assess injuries from rapid

  5. Exercise with prebreathe appears to increase protection from decompression sickness: Preliminary findings

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Fischer, Michele D.; Heaps, Cristine L.; Pilmanis, Andrew A.

    1994-01-01

    Extravehicular activity (EVA) from the Space Shuttle involves one hour of prebreath with 100% oxygen, decompression of the entire Shuttle to 10.2 psia for at least 12 hours, and another prebreath for 40 minutes before decompression to the 4.3 psia suit pressure. We are investigating the use of a one-hour prebreathe with 100% oxygen beginning with a ten-minute strenuous exercise period as an alternative for the staged decompression schedule described above. The 10-minute exercise consists of dual-cycle ergometry performed at 75% of the subject's peak oxygen uptake to increase denitrogenation efficiency by increasing ventilation and perfusion. The control exposures were preceded by a one-hour prebreathe with 100% oxygen while resting in a supine position. The twenty-two male subjects were exposed to 4.3 psia for 4 hours while performing light to moderate exercise. Preliminary results from 22 of the planned 26 subjects indicate 76% DCS following supine, resting prebreathe and 38% following prebreathe with exercise. The staged decompression schedule has been shown to result in 23% DCS which is not significantly different from the exercise-enhanced prebreathe results. Prebreathe including exercise appears to be comparable to the protection afforded by the more lengthy staged decompression schedule. Completion of the study later this year will enable planned statistical analysis of the results.

  6. Decompression sickness bubbles: are gas micronuclei formed on a flat hydrophobic surface?

    PubMed

    Arieli, R; Marmur, A

    2011-06-30

    It is a long-standing hypothesis that the bubbles which evolve as a result of decompression have their origin in stable gas micronuclei lodged in hydrophobic crevices, micelles of surface-active molecules, or tribonucleation. Recent findings supported by atomic force microscopy have indicated that tiny, flat nanobubbles form spontaneously on smooth, hydrophobic surfaces submerged in water. We propose that these nanobubbles may be the gas micronuclei responsible for the bubbles that evolve to cause decompression sickness. To support our hypothesis, we used hydrophilic and monolayer-covered hydrophobic smooth silicon wafers. The experiment was conducted in three main stages. Double distilled water was degassed at the low pressure of 5.60 kPa; hydrophobic and hydrophilic silicon wafers were placed in a bowl of degassed water and left overnight at normobaric pressure. The bowl was then placed in the hyperbaric chamber for 15 h at a pressure of 1013 kPa (=90 m sea water). After decompression, bubbles were observed and photographed. The results showed that bubbles only evolved on the hydrophobic surfaces following decompression. There are numerous hydrophobic surfaces within the living body (e.g., in the large blood vessels), which may thus be the sites where nanobubbles that serve as gas micronuclei for bubble evolution following decompression are formed. PMID:21376842

  7. Step activity monitoring in lumbar stenosis patients undergoing decompressive surgery

    PubMed Central

    Schubert, Tim; Winter, Corinna; Brandes, Mirko; Hackenberg, Lars; Wassmann, Hansdetlef; Liem, Dennis; Rosenbaum, Dieter; Bullmann, Viola

    2010-01-01

    Symptomatic degenerative central lumbar spinal stenosis (LSS) is a frequent indication for decompressive spinal surgery, to reduce spinal claudication. No data are as yet available on the effect of surgery on the level of activity measured with objective long-term monitoring. The aim of this prospective, controlled study was to objectively quantify the level of activity in central LSS patients before and after surgery, using a continuous measurement device. The objective data were correlated with subjective clinical results and the radiographic degree of stenosis. Forty-seven patients with central LSS and typical spinal claudication scheduled for surgery were included. The level of activity (number of gait cycles) was quantified for 7 consecutive days using the StepWatch Activity Monitor (SAM). Visual analogue scales (VAS) for back and leg pain, Oswestry disability index and Roland–Morris score were used to assess the patients’ clinical status. The patients were investigated before surgery and 3 and 12 months after surgery. In addition, the radiographic extent of central LSS was measured digitally on preoperative magnetic resonance imaging or computed tomography. The following results were found preoperatively: 3,578 gait cycles/day, VAS for back pain 5.7 and for leg pain 6.5. Three months after surgery, the patients showed improvement: 4,145 gait cycles/day, VAS for back pain 4.0 and for leg pain 3.0. Twelve months after surgery, the improvement continued: 4,335 gait cycles/day, VAS for back pain 4.1 and for leg pain 3.3. The clinical results and SAM results showed significant improvement when preoperative data were compared with data 3 and 12 months after surgery. The results 12 months after surgery did not differ significantly from those 3 months after surgery. The level of activity correlated significantly with the degree of leg pain. The mean cross-sectional area of the spinal canal at the central LSS was 94 mm2. The radiographic results did not

  8. [Dynamics of intracranial pressure in patients with massive ischemic stroke after decompressive craniotomy].

    PubMed

    Nikitin, A S; Burov, S A; Petrikov, S S; Asratian, S A; Gorshkov, K M; Krylov, V V

    2013-01-01

    The goal of the study was assessment of the value of ICP monitoring in patients with massive ischemic stroke after decompressive craniotomy. 12 patients with massive ischemic stroke were performed ICP monitoring after decompressive craniotomy. We identified 3 types of ICP dynamics: a) normal ICP, which no need to treat; b) ICP elevation to 20 mm Hg and more in postoperative period, which can be treated by nonsurgical therapy; c) refractory to therapy ICP elevation to 20 mm Hg and more with development of intracranial hypertension. We consider that ICP monitoring in patients with massive ischemic stroke after decompressive craniotomy can be useful for optimization of the therapy and correction of intracranial hypertension. PMID:24341041

  9. Laboratory evidence of fragmentation during slow decompression of a magma analogue containing volatiles and solid particles.

    NASA Astrophysics Data System (ADS)

    Rivalta, Eleonora; Pascal, Karen; Phillips, Jeremy; Bonaccorso, Alessandro

    2010-05-01

    With the motivation of studying switches in the eruption regime at Stromboli volcano, we performed a series of shock-tube experiments decompressing Gum Rosin dissolved in acetone (GRA mixture) as a volatile-bearing analog of magma, obtaining for the first time evidence of fragmentation of a natural system containing solved volatiles and solid particles during slow decompression. We exposed the magma analog to sudden decompression and to slow decompressions of the order of about 100-400 Pa s-1 from atmospheric pressure patm down to different pressures pL. We used five different concentrations of acetone in the mixture: 15%, 23%, 30%, 35%, 40%. This corresponds to about 2 - 6% H2O in magma. We use our sudden decompression experiments to draw a phase diagram of our mixture. During fast decompression, we first observe bubble nucleation for pL ≈ 25 kPa. For 13 kPa < pL < 18 kPa we observe progressively more intense boiling of acetone in the mixture. If the mixture is decompressed down to pL = 5 - 12 kPa, we observe slow expansion of foam (velocity of the order of a few mm-cm per second). If pL < 5 kPa, we observe fragmentation (velocity of expansion is tens of meters per second). Mixtures of different concentrations show somewhat different values of the maximum pressure at which fragmentation is observed. During slow decompression, in general we observe a similar behavior, albeit with slightly different threshold values of pL, except that in general fragmentation does not occur at all. However, in some cases we surprisingly do not observe any bubble nucleating around the boiling point of acetone. In those cases, fragmentation occurs when pressure reaches about pL = 8 - 10 kPa. The mixture apparently becomes supersaturated even if small rosin particles, which should ease nucleation, populate the mixture, as we could ascertain observing the samples at the microscope. Fragmentation events during slow decompression occurred only - but not always -when decompressing the

  10. Indication and technique of transnasal microscopic orbital decompression for endocrine ophthalmopathy.

    PubMed

    May, A; Fries, U; von Ilberg, C; Weber, A

    2000-01-01

    If endocrine ophthalmopathy progresses despite conservative treatment then indications for surgical decompression are: loss of visual acuity, increasing strabism, and severe keratopathy. Endonasal microsurgery ensures a binocular view onto the intranasal landmarks of the orbital walls and allows simultaneous decompression of the medial and inferior wall as well as a good relief of pressure at the orbital apex. Surgical decompressions were performed on 29 orbits in 19 patients, 16 by using the endonasal microsurgical, 3 via external approach. The microscopic approach was entirely comparable with regard to the reduction of proptosis with a mean improvement of 4.2 mm against a mean of 4.7 mm by external approach and a mean 0.2 of better visual acuity in both procedures. The microsurgical technique is considered superior to an external approach avoiding external scars, neural pain, and reportedly less diplopia. The healing phase and the hospitalization time are shorter. PMID:10810256

  11. Decompression sickness and venous gas emboli at 8.3 psia

    NASA Technical Reports Server (NTRS)

    Smead, Kenneth W.; Dixon, Gene A.; Webb, James T.; Krutz, Robert W., Jr.

    1987-01-01

    This study sought to determine the bends risk on decompression from sea level to 8.3 psia. On the basis of several prior studies by NASA and the Air Force, this differential was expected to result in a minimal (about 5 percent) incidence of mild decompression sickness, and may be the pressure of choice for the next-generation NASA extravehicular activity (EVA) pressure suit. Thirty-one volunteer subjects, performing light work characteristic of EVA, were exposed to 8.3 psia pressure altitude for six hours. Limb bends incidence was 3.2 percent, and 25.8 percent of the subjects demonstrated significant intravascular bubbling. Those who bubbled were significantly older than the bubble-free group, but differed in no other aspect. An 8.3 psia advanced pressure suit design was considered insufficient to totally preclude the risk of decompression sickness.

  12. Preconditioning methods and mechanisms for preventing the risk of decompression sickness in scuba divers: a review.

    PubMed

    Gempp, Emmanuel; Blatteau, Jean-Eric

    2010-07-01

    Scuba divers are at risk of decompression sickness due to the excessive formation of gas bubbles in blood and tissues following ascent, with potentially subsequent neurological injuries. Since nonprovocative dive profiles are no guarantor of protection against this disease, novel means are required for its prevention including predive procedures that could induce more resistance to decompression stress. In this article, we review the recent studies describing the promising preconditioning methods that might operate on the attenuation of bubble formation believed to reduce the occurrence of decompression sickness. The main practical applications are simple and feasible predive measures such as endurance exercise in a warm environment, oral hydration, and normobaric oxygen breathing. Rheological changes affecting tissue perfusion, endothelial adaptation with nitric oxide pathway, up-regulation of cytoprotective proteins, and reduction of preexisting gas nuclei from which bubbles grow could be involved in this protective effect. PMID:20623437

  13. [Neurological decompression illness in a Japanese breath-held diver: a case report].

    PubMed

    Matsuo, Ryu; Arakawa, Shuji; Furuta, Yoshihiko; Kanazawa, Yuka; Kamouchi, Masahiro; Kitazono, Takanari

    2012-01-01

    We report a Japanese breath-hold diver (Ama) who presented neurological disorders after diving. He repeated diving into 25-30 meters depth in the sea for 6 hours. After diving, he felt dizziness and unsteady gait. Neurological examination showed left quadrant hemianopia, bilateral limb ataxia and ataxic gait. Head CT revealed gas bubbles in the left parietal lobe. In CT scan on 3 days after onset, gas bubbles disappeared and low density areas were observed in the bilateral parietal lobes. Brain imaging (DWI, T(2)WI and FLAIR) demonstrated high intensity in the parieto-occipital lobes. Neither pulmonary barotrauma nor intracardiac shunt was detected. He was diagnosed as having neurological decompression illness and therefore underwent hyperbaric oxygen therapy. The pathogenesis of this case was considered to be microbubbles induced by decompression. The present case suggests that repetitive rapid surfacing from the deep sea causes neurological decompression illness even in the breath-hold diver. PMID:23064626

  14. Role of Decompression in Late Presentation of Cervical Spinal Cord Disorders

    PubMed Central

    Sakale, Harshal; Dulani, Rajesh; Singh, Pradeep K; Sanrakhia, Manoj

    2014-01-01

    Study Design Prospective study conducted at Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences, Wardha, India. Purpose To show the efficacy of decompression in the late presentation of cervical spinal cord disorders. Overview of Literature Studies by various authors have shown that early spinal decompression results in better neurological outcomes. Methods From January 2003 to January 2005, 11 of the 41 patients with cervical spinal cord compression, meeting the inclusion criteria, underwent anterior decompression; interbody graft placement and stabilization by anterior cervical locking plate. The neurologic and functional outcomes were recorded. Results Five patients had spinal cord injury and 6 patients had compressive cervical myelopathy. Complications included 1 death and 1 plate loosening. No patient lost their preoperative neurological status. One patient had no improvement, 2 patients showed full recovery. The mean follow-up is 28.3 month. At the of rehabilitation, 6 were able to walk without support), 2 could walk with support, and 1 needed a wheelchair. The average American Spinal Injury Association motor score on admission to the hospital, 32.8 (standard deviation [SD], 30.5); admission to rehabilitation, 38.6 (SD, 32.4); discharge from rehabilitation, 46.2 (SD, 33.7). The most recent follow-up was 64.0 (SD, 35.3). Conclusions The anterior approach for cervical decompression allows for adequate decompression. This decompression is the best chance offered in even late reported cases, including posttraumatic cases where there is no evidence of cord transactions. The use of anterior cervical plates reduces the chances of graft loosening, extruding, or collapsing. PMID:24761201

  15. Dibutyryl cAMP effects on thromboxane and leukotriene production in decompression-induced lung injury

    NASA Technical Reports Server (NTRS)

    Little, T. M.; Butler, B. D.

    1997-01-01

    Decompression-induced venous bubble formation has been linked to increased neutrophil counts, endothelial cell injury, release of vasoactive eicosanoids, and increased vascular membrane permeability. These actions may account for inflammatory responses and edema formation. Increasing the intracellular cAMP has been shown to decrease eicosanoid production and edema formation in various models of lung injury. Reduction of decompression-induced inflammatory responses was evaluated in decompressed rats pretreated with saline (controls) or dibutyryl cAMP (DBcAMP, an analog of cAMP). After pretreatment, rats were exposed to either 616 kPa for 120 min or 683 kPa for 60 min. The observed increases in extravascular lung water ratios (pulmonary edema), bronchoalveolar lavage, and pleural protein in the saline control group (683 kPa) were not evident with DBcAMP treatment. DBcAMP pretreatment effects were also seen with the white blood cell counts and the percent of neutrophils in the bronchoalveolar lavage. Urinary levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were significantly increased with the 683 kPa saline control decompression exposure. DBcAMP reduced the decompression-induced leukotriene E4 production in the urine. Plasma levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were increased with the 683-kPa exposure groups. DBcAMP treatment did not affect these changes. The 11-dehydrothromboxane B2 and leukotriene E4 levels in the bronchoalveolar lavage were increased with the 683 kPa exposure and were reduced with the DBcAMP treatment. Our results indicate that DBcAMP has the capability to reduce eicosanoid production and limit membrane permeability and subsequent edema formation in rats experiencing decompression sickness.

  16. Delayed brittle-like fragmentation of vesicular magma analogue by decompression

    NASA Astrophysics Data System (ADS)

    Kameda, Masaharu; Ichihara, Mie; Shimanuki, Susumu; Okabe, Wataru; Shida, Tsukasa

    2013-05-01

    A rapid decompression experiment using syrup containing gas bubbles was conducted in order to clarify the fragmentation of vesicular magma, which is a key phenomenon in volcanic eruptions. We focus on brittle-like fragmentation, which occurs with a longer time scale than brittle fragmentation. The response of the bubbly syrup to the decompression for various viscosities and porosities was tested under various initial pressures, pressure differences, and decompression times. The response observed by high-speed photography was classified using the Deborah number DeDT, which is defined as the ratio of the viscoelastic relaxation time of the syrup to the decompression time, the maximum differential stress at the bubble surface Δσmax, and a measure of instantaneous brittleness at the bubble surface βc at the time when the differential stress at the surface reaches the critical fracture stress Δσc. In a number of the experimental runs in which both DeDT and βc indicated ductile response of the material, brittle-like fragmentation occurred when Δσmax substantially exceeded Δσc. For all of the runs in which brittle-like fragmentation was observed, the onset of fragmentation was delayed substantially from the relaxation time, whereas the onset occurred within the characteristic time for viscous expansion of the bubbles. In many cases of brittle-like fragmentation, fragmentation continued after the onset triggered by a single decompression event. Detailed analysis indicates that brittle-like fragmentation started with a sudden release of the gas in the bubbly syrup through a surface crack, which might lead to an increase in local brittleness. Magma fragmentation may be viewed as sequential brittle-like fragmentation. This view may provide an explanation for the observed time delay for the onset of an explosive eruption after a triggering decompression event.

  17. Decompression sickness in a vegetarian diver: are vegetarian divers at risk? A case report.

    PubMed

    van Hulst, Robert A; van der Kamp, Wim

    2010-01-01

    We present a case of a diver who suffered decompression sickness (DCS), but who also was a strict vegetarian for more than 10 years. He presented with symptoms of tingling of both feet and left hand, weakness in both legs and sensory deficits for vibration and propriocepsis after two deep dives with decompression. The initial clinical features of this case were most consistent with DCS, possibly because of a vulnerable spinal cord due to cobalamin deficiency neuropathy. This case illustrates the similarities between DCS and a clinically defined vitamin B12 deficiency. The pathophysiology of vitamin B12 deficiency and common pathology and symptoms of DCS are reviewed. PMID:20568548

  18. Statistical comparison of pooled nitrogen washout data of various altitude decompression response groups

    NASA Technical Reports Server (NTRS)

    Edwards, B. F.; Waligora, J. M.; Horrigan, D. J., Jr.

    1985-01-01

    This analysis was done to determine whether various decompression response groups could be characterized by the pooled nitrogen (N2) washout profiles of the group members, pooling individual washout profiles provided a smooth time dependent function of means representative of the decompression response group. No statistically significant differences were detected. The statistical comparisons of the profiles were performed by means of univariate weighted t-test at each 5 minute profile point, and with levels of significance of 5 and 10 percent. The estimated powers of the tests (i.e., probabilities) to detect the observed differences in the pooled profiles were of the order of 8 to 30 percent.

  19. Doppler detection of decompression bubbles with computer assisted digitization of ultrasonic signals

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Robinson, R.; Fife, C.; Sutton, T.

    1991-01-01

    The use of an inexpensive, commercially available audio digitizer in conjunction with a PC to digitize Doppler bubble signals for visual and electronic evaluation is reported. This device can be operated simultaneously with Doppler audio monitoring. Precordial and arterial Doppler recordings of gas bubbles were obtained from anesthetized dogs after intravascular infusion or following decompression. Additional evaluations were conducted on Doppler bubble recordings obtained from human decompression studies. The device can be used in real-time or for later signal analysis. Accompanying menu-driven software provides for numerous signal modification options and visual displays. This device can provide a simultaneous visual display of Doppler signals normally available only for audio evaluation.

  20. Blood biochemical and cellular changes during a decompression procedure involving eight hours of oxygen prebreathing

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.

    1989-01-01

    Chemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 8 h of oxygen prebreathing. The exposure was designed to simulate space-flight extravehicular activity (EVA) for 6 h. Several statistically significant changes in blood parameters were observed following the exposure: increases in calcium, magnesium, osmolality, low-density lipoprotein cholesterol, monocytes, and prothrombin time, and decreases in chloride, creatine phosphokinase and eosinophils. The changes, however, were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression profile used in this study is not likely to result in blood changes that would pose a threat to astronauts during EVA.

  1. Airplane transport isolators may loose leak tightness after rapid cabin decompression.

    PubMed

    Albrecht, Roland; Kunz, Andres; Voelckel, Wolfgang G

    2015-01-01

    Air medical transport of patients suffering of highly infectious diseases is typically performed employing portable isolation chambers. Although the likelihood of decompression flight emergencies is low, sustainability of the devices used is crucial. When a standard isolation unit was subjected to an explosive cabin decompression of 493 hPa, simulating a 32808 ft flight level accident, leak tightness of the unit was lost due to rupture of the bag caused by over expansion. When the pressure chamber experiment was repeated with a modified unit, distension was minimized by an additional compensation air bag, thus ensuring leak tightness. PMID:25887737

  2. Image compression/decompression based on mathematical transform, reduction/expansion, and image sharpening

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1997-01-01

    An image represented in a first image array of pixels is first decimated in two dimensions before being compressed by a predefined compression algorithm such as JPEG. Another possible predefined compression algorithm can involve a wavelet technique. The compressed, reduced image is then transmitted over the limited bandwidth transmission medium, and the transmitted image is decompressed using an algorithm which is an inverse of the predefined compression algorithm (such as reverse JPEG). The decompressed, reduced image is then interpolated back to its original array size. Edges (contours) in the image are then sharpened to enhance the perceptual quality of the reconstructed image. Specific sharpening techniques are described.

  3. Image compression/decompression based on mathematical transform, reduction/expansion, and image sharpening

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1997-12-30

    An image represented in a first image array of pixels is first decimated in two dimensions before being compressed by a predefined compression algorithm such as JPEG. Another possible predefined compression algorithm can involve a wavelet technique. The compressed, reduced image is then transmitted over the limited bandwidth transmission medium, and the transmitted image is decompressed using an algorithm which is an inverse of the predefined compression algorithm (such as reverse JPEG). The decompressed, reduced image is then interpolated back to its original array size. Edges (contours) in the image are then sharpened to enhance the perceptual quality of the reconstructed image. Specific sharpening techniques are described. 22 figs.

  4. Extreme events in computational turbulence

    PubMed Central

    Yeung, P. K.; Zhai, X. M.; Sreenivasan, Katepalli R.

    2015-01-01

    We have performed direct numerical simulations of homogeneous and isotropic turbulence in a periodic box with 8,1923 grid points. These are the largest simulations performed, to date, aimed at improving our understanding of turbulence small-scale structure. We present some basic statistical results and focus on “extreme” events (whose magnitudes are several tens of thousands the mean value). The structure of these extreme events is quite different from that of moderately large events (of the order of 10 times the mean value). In particular, intense vorticity occurs primarily in the form of tubes for moderately large events whereas it is much more “chunky” for extreme events (though probably overlaid on the traditional vortex tubes). We track the temporal evolution of extreme events and find that they are generally short-lived. Extreme magnitudes of energy dissipation rate and enstrophy occur simultaneously in space and remain nearly colocated during their evolution. PMID:26424452

  5. Hazards of high altitude decompression sickness during falls in barometric pressure from 1 atm to a fraction thereof

    NASA Technical Reports Server (NTRS)

    Genin, A. M.

    1980-01-01

    Various tests related to studies concerning the effects of decompression sicknesses at varying pressure levels and physical activity are described. The tests indicate that there are no guarantees of freedom from decompression sicknesses when man transitions from a normally oxygenated normobaric nitrogen-oxygen atmosphere into an environment having a 0.4 atm or lower pressure and he is performing physical work.

  6. The Evolution of Crystal Textures along Varied Degassing Paths: Insights from Experimental Decompression of Rhyodacite Melt Saturated with H2O and H2O-CO2 Fluids

    NASA Astrophysics Data System (ADS)

    Riker, J.; Blundy, J.; Rust, A.; Cashman, K. V.

    2013-12-01

    Magma ascent is intimately linked to the style of volcanic eruptions. The reasons for this are largely kinetic: timescales of decompression-driven vesiculation and crystallization strongly influence the ease of gas escape from viscous melts. The interplay between gas loss and crystallization is therefore relevant to a wide spectrum of eruptive behaviour, from explosive to effusive, and to the transitions between endmember eruptive styles. Experiments simulating magmatic decompression provide a means of calibrating the textures and compositions of erupted products against known ascent conditions. A key theme arising from the growing cache of experimental data is that decompression path - not simply decompression rate - dramatically affects the time evolution of crystal abundances and textures. Here we present the results of high-temperature, high-pressure decompression experiments designed to assess the effect of degassing path on progressive crystallisation of Mount St. Helens rhyodacite. Three families of experiments were employed to simulate varied PH2O-t trajectories: single-step, water-saturated ascent; continuous, water-saturated ascent; and continuous, H2O-CO2 saturated ascent. Experimental decompression rates range from 1 to >1000 MPa hr-1. Quantitative textural data (abundance, number density, and size) have been used to calculate time-averaged plagioclase nucleation (10-2-101 mm-3 s-1) and growth (10-8-10-6 mm s-1) rates in run products. As anticipated, instantaneous decompressions yield higher nucleation rates than slower decompressions; however, the presence of CO2 also increases nucleation rates relative to the pure water case. These early-formed textural distinctions persist even at the lowest pressures examined, suggesting that deep H2O-CO2 fluids leave a lasting textural 'fingerprint' on magmas that ascend to shallower portions of the magmatic plumbing system. Growth on pre-existing crystals contributes significantly to added crystallization at a

  7. Determinants of Toxicity, Patterns of Failure, and Outcome Among Adult Patients With Soft Tissue Sarcomas of the Extremity and Superficial Trunk Treated With Greater Than Conventional Doses of Perioperative High-Dose-Rate Brachytherapy and External Beam Radiotherapy

    SciTech Connect

    San Miguel, Inigo; San Julian, Mikel; Cambeiro, Mauricio; Sanmamed, Miguel Fernandez; Vazquez-Garcia, Blanca; Pagola, Maria; Gaztanaga, Miren; Martin-Algarra, Salvador; Martinez-Monge, Rafael

    2011-11-15

    Purpose: The present study was undertaken to determine factors predictive of toxicity, patterns of failure, and survival in 60 adult patients with soft tissue sarcomas of the extremity and superficial trunk treated with combined perioperative high-dose-rate brachytherapy and external beam radiotherapy. Methods and Materials: The patients were treated with surgical resection and perioperative high-dose-rate brachytherapy (16 or 24 Gy) for negative and close/microscopically positive resection margins, respectively. External beam radiotherapy (45 Gy) was added postoperatively to reach a 2-Gy equivalent dose of 62.9 and 72.3 Gy, respectively. Adjuvant chemotherapy with ifosfamide and doxorubicin was given to patients with advanced high-grade tumors. Results: Grade 3 toxic events were observed in 18 patients (30%) and Grade 4 events in 6 patients (10%). No Grade 5 events were observed. A location in the lower limb was significant for Grade 3 or greater toxic events on multivariate analysis (p = .013), and the tissue volume encompassed by the 150% isodose line showed a trend toward statistical significance (p = .086). The local control, locoregional control, and distant control rate at 9 years was 77.4%, 69.5%, and 63.8%, respectively. On multivariate analysis, microscopically involved margins correlated with local control (p = .036) and locoregional control (p = .007) and tumor size correlated with distant metastases (p = .004). The 9-year disease-free survival and overall survival rate was 47.0% and 61.5%, respectively. Multivariate analysis showed poorer disease-free survival rates for patients with tumors >6 cm (p = .005) and microscopically involved margins (p = .043), and overall survival rates decreased with increasing tumor size (p = .011). Conclusions: Grade 3 or greater wound complications can probably be decreased using meticulous treatment planning to decrease the tissue volume encompassed by the 150% isodose line, especially in lower limb locations

  8. Use of liposomal bupivacaine in the postoperative management of posterior spinal decompression.

    PubMed

    Grieff, Anthony N; Ghobrial, George M; Jallo, Jack

    2016-07-01

    OBJECTIVE The aim in this paper was to evaluate the efficacy of long-acting liposomal bupivacaine in comparison with bupivacaine hydrochloride for lowering postoperative analgesic usage in the management of posterior cervical and lumbar decompression and fusion. METHODS A retrospective cohort-matched chart review of 531 consecutive cases over 17 months (October 2013 to February 2015) for posterior cervical and lumbar spinal surgery procedures performed by a single surgeon (J.J.) was performed. Inclusion criteria for the analysis were limited to those patients who received posterior approach decompression and fusion for cervical or lumbar spondylolisthesis and/or stenosis. Patients from October 1, 2013, through December 31, 2013, received periincisional injections of bupivacaine hydrochloride, whereas after January 1, 2014, liposomal bupivacaine was solely administered to all patients undergoing posterior approach cervical and lumbar spinal surgery through the duration of treatment. Patients were separated into 2 groups for further analysis: posterior cervical and posterior lumbar spinal surgery. RESULTS One hundred sixteen patients were identified: 52 in the cervical cohort and 64 in the lumbar cohort. For both cervical and lumbar cases, patients who received bupivacaine hydrochloride required approximately twice the adjusted morphine milligram equivalent (MME) per day in comparison with the liposomal bupivacaine groups (5.7 vs 2.7 MME, p = 0.27 [cervical] and 17.3 vs 7.1 MME, p = 0.30 [lumbar]). The amounts of intravenous rescue analgesic requirements were greater for bupivacaine hydrochloride in comparison with liposomal bupivacaine in both the cervical (1.0 vs 0.39 MME, p = 0.31) and lumbar (1.0 vs 0.37 MME, p = 0.08) cohorts as well. None of these differences was found to be statistically significant. There were also no significant differences in lengths of stay, complication rates, or infection rates. A subgroup analysis of both cohorts of opiate-naive versus

  9. Volumetric analysis of syringomyelia following hindbrain decompression for Chiari malformation Type I: syringomyelia resolution follows exponential kinetics

    PubMed Central

    Coumans, Jean-Valery; Walcott, Brian P.; Butler, William E.; Nahed, Brian V.; Kahle, Kristopher T.

    2013-01-01

    Object Resolution of syringomyelia is common following hindbrain decompression for Chiari malformation, yet little is known about the kinetics governing this process. The authors sought to establish the volumetric rate of syringomyelia resolution. Methods A retrospective cohort of patients undergoing hindbrain decompression for a Chiari malformation Type I with preoperative cervical or thoracic syringomyelia was identified. Patients were included in the study if they had at least 3 neuroimaging studies that detailed the entirety of their preoperative syringomyelia over a minimum of 6 months postoperatively. The authors reconstructed the MR images in 3 dimensions and calculated the volume of the syringomyelia. They plotted the syringomyelia volume over time and constructed regression models using the method of least squares. The Akaike information criterion and Bayesian information criterion were used to calculate the relative goodness of fit. The coefficients of determination R2 (unadjusted and adjusted) were calculated to describe the proportion of variability in each individual data set accounted for by the statistical model. Results Two patients were identified as meeting inclusion criteria. Plots of the least-squares best fit were identified as 4.01459e−0.0180804x and 13.2556e−0.00615859x. Decay of the syringomyelia followed an exponential model in both patients (R2 = 0.989582 and 0.948864). Conclusions Three-dimensional analysis of syringomyelia resolution over time enables the kinetics to be estimated. This technique is yet to be validated in a large cohort. Because syringomyelia is the final common pathway for a number of different pathological processes, it is possible that this exponential only applies to syringomyelia related to treatment of Chiari malformation Type I. PMID:21882909

  10. Treatment of upper-extremity outflow thrombosis.

    PubMed

    van den Houten, Marijn Ml; van Grinsven, Regine; Pouwels, Sjaak; Yo, Lonneke Sf; van Sambeek, Marc Rhm; Teijink, Joep Aw

    2016-03-01

    Approximately 10% of all cases of deep vein thrombosis (DVT) occur in the upper extremities. The most common secondary cause of upper-extremity DVT (UEDVT) is the presence of a venous catheter. Primary UEDVT is far less common and usually occurs in patients with anatomic abnormalities of the costoclavicular space causing compression of the subclavian vein, called venous thoracic outlet syndrome (VTOS). Subsequently, movement of the arm results in repetitive microtrauma to the vein and its surrounding structures causing apparent 'spontaneous' thrombosis, or Paget-Schrötter syndrome. Treatment of UEDVT aims at elimination of the thrombus, thereby relieving acute symptoms, and preventing recurrence. Initial management for all UEDVT patients consists of anticoagulant therapy. In patients with Paget-Schrötter syndrome the underlying VTOS necessitates a more aggressive management strategy. Several therapeutic options exist, including catheter-directed thrombolysis, surgical decompression through first rib resection, and percutaneous transluminal angioplasty of the vein. However, several controversies exist regarding their indication and timing. PMID:26916766

  11. The Decompression Sickness and Venous Gas Emboli Consequences of Air Breaks During 100% Oxygen Prebreathe

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Gernhardt, M. L.; Powell, M. R.

    2004-01-01

    Not enough is known about the increased risk of hypobaric decompression sickness (DCS) and production of venous (VGE) and arterial (AGE) gas emboli following an air break in an otherwise normal 100% resting oxygen (O2) prebreathe (PB), and certainly a break in PB when exercise is used to accelerate nitrogen (N2) elimination from the tissues. Current Aeromedical Flight Rules at the Johnson Space Center about additional PB payback times are untested, possibly too conservative, and therefore not optimized for operational use. A 10 min air break at 90 min into a 120 min PB that includes initial dual-cycle ergometry for 10 min will show a measurable increase in the risk of DCS and VGE after ascent to 4.3 psia compared to a 10 min break at 15 min into the PB, or when there is no break in PB. Data collection with humans begins in 2005, but here we first evaluate the hypothesis using three models of tissue N2 kinetics: Model I is a simple single half-time compartment exponential model, Model II is a three compartment half-time exponential model, and Model III is a variable half-time compartment model where the percentage of maximum O2 consumption for the subject during dual-cycle ergometry exercise defines the half-time compartment. Model I with large rate constants to simulate an exercise effect always showed a late break in PB had the greatest consequence. Model II showed an early break had the greatest consequence. Model III showed there was no difference between early or late break in exercise PB. Only one of these outcomes will be observed when humans are tested. Our results will favor one of these models, and so advance our understanding of tissue N2 kinetics, and of altitude DCS after an air break in PB.

  12. Effectiveness of Intraluminal Air Decompression on Postcolonoscopic Pain According to Reinsertion Site

    PubMed Central

    Sur, Young-Jin; Jung, Seung-Jin; Lee, Dong-Won; Cho, Sang-Hyun; Kim, Ryang-Pyo; Kim, Tae-Wan; Shin, Hyeon-Guk; Hong, A-Ram; Kwon, Hyun-Woo

    2016-01-01

    Background Colonoscopy is a very effective and essential examination to diagnose colorectal cancer; however, many patients experience discomfort due to post-examination abdominal pain, which reduces colonoscopy compliance. This study was conducted to determine methods for reducing post-colonoscopic abdominal pain. Methods We conducted a randomized controlled study of 405 male and female adults who visited Hana General Hospital in Cheongju. We surveyed general characteristics, history of colonoscopy, and other related factors, then categorized examinees into 5 groups (0–5) according to the site of scope reinsertion. Pain was measured using a numeric rating scale (NRS). Results The mean age of examinees in this study was 47.8 years, and 210 participants had prior experience of colonoscopy. No significant difference was observed between variables, with the exception of reinsertion duration (P=0.005). Pain scores were different between performing physicians (P=0.006), and were higher when the subjective level of procedure difficulty was low (P=0.026) in univariate analysis. Pain scores decreased as the reinsertion site became closer to the proximal colon (P<0.001), but there was no significant difference between groups 3 and 4. The results of multiple logistic regression analysis, including univariate analysis, showed that group 1 had 0.48 times, group 2 had 0.38 times, group 3 had 0.09 times, and group 4 had 0.03 times odds ratio (moderate-to-severe pain, NRS ≥4) than control group 0. Conclusion Air decompression by scope reinsertion is an effective way to reduce abdominal pain after colonoscopy. Removing air when the reinserted scope approaches the hepatic flexure seems to be the most effective method to reduce post-colonoscopic pain. PMID:27274386

  13. Outcomes after suboccipital decompression without dural opening in children with Chiari malformation Type I

    PubMed Central

    Kennedy, Benjamin C.; Kelly, Kathleen M.; Phan, Michelle Q.; Bruce, Samuel S.; McDowell, Michael M.; Anderson, Richard C. E.; Feldstein, Neil A.

    2015-01-01

    Object Symptomatic pediatric Chiari malformation Type I (CM-I) is most often treated with posterior fossa decompression (PFD), but controversy exists over whether the dura needs to be opened during PFD. While dural opening as a part of PFD has been suggested to result in a higher rate of resolution of CM symptoms, it has also been shown to lead to more frequent complications. In this paper, the authors present the largest reported series of outcomes after PFD without dural opening surgery, as well as identify risk factors for recurrence. Methods The authors performed a retrospective review of 156 consecutive pediatric patients in whom the senior authors performed PFD without dural opening from 2003 to 2013. Patient demographics, clinical symptoms and signs, radiographic findings, intraoperative ultrasound results, and neuromonitoring findings were reviewed. Univariate and multivariate regression analyses were performed to determine risk factors for recurrence of symptoms and the need for reoperation. Results Over 90% of patients had a good clinical outcome, with improvement or resolution of their symptoms at last follow-up (mean 32 months). There were no major complications. The mean length of hospital stay was 2.0 days. In a multivariate regression model, partial C-2 laminectomy was an independent risk factor associated with reoperation (p = 0.037). Motor weakness on presentation was also associated with reoperation but only with trend-level significance (p = 0.075). No patient with < 8 mm of tonsillar herniation required reoperation. Conclusions The vast majority (> 90%) of children with symptomatic CM-I will have improvement or resolution of symptoms after a PFD without dural opening. A non–dural opening approach avoids major complications. While no patient with tonsillar herniation < 8 mm required reoperation, children with tonsillar herniation at or below C-2 have a higher risk for failure when this approach is used. PMID:25932779

  14. Decompression Sickness After Air Break in Prebreathe Described with a Survival Model

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Pilmanis, A. A.

    2010-01-01

    Data from Brooks City-Base show the decompression sickness (DCS) and venous gas emboli (VGE) consequences of air breaks in a resting 100% O2 prebreathe (PB) prior to a hypobaric exposure. METHODS: DCS and VGE survival times from 95 controls for a 60 min PB prior to 2-hr or 4-hr exposures to 4.37 psia are statistically compared to 3 break in PB conditions: a 10 min (n=40), 20 min (n=40), or 60 min break (n=32) 30 min into the PB followed by 30 min of PB. Ascent rate was 1,524 meters / min and all exposures included light exercise and 4 min of VGE monitoring of heart chambers at 16 min intervals. DCS survival time for combined control and air breaks were described with an accelerated log logistic model where exponential N2 washin during air break was described with a 10 min half-time and washout during PB with a 60 min half-time. RESULTS: There was no difference in VGE or DCS survival times among 3 different air breaks, or when air breaks were compared to control VGE times. However, 10, 20, and 60 min air breaks had significantly earlier survival times compared to control DCS times, certainly early in the exposures. CONCLUSION: Air breaks of 10, 20, and 60 min after 30 min of a 60 min PB reduced DCS survival time. The survival model combined discrete comparisons into a global description mechanistically linked to asymmetrical N2 washin and washout kinetics based on inspired pN2. Our unvalidated regression is used to compute additional PB time needed to compensate for an air break in PB within the range of tested conditions.

  15. Analysis of patients with decompression illness transported via physician-staffed emergency helicopters

    PubMed Central

    Oode, Yasumasa; Yanagawa, Youichi; Omori, Kazuhiko; Osaka, Hiromichi; Ishikawa, Kouhei; Tanaka, Hiroshi

    2015-01-01

    Context: There have been few reports investigating the effects of air transportation on patients with decompression illness (DCI). Aims: To investigate the influence of air transportation on patients with DCI transported via physician-staffed emergency helicopters (HEMS: Emergency medical system of physician-staffed emergency helicopters). Settings and Design: A retrospective medical chart review in a single hospital. Materials and Methods: A medical chart review was retrospectively performed in all patients with DCI transported via HEMS between July 2009 and June 2013. The exclusion criteria included cardiopulmonary arrest on surfacing. Statistical analysis used: The paired Student's t-test. Results: A total of 28 patients were treated as subjects. Male and middle-aged subjects were predominant. The number of patients who suddenly surfaced was 15/28. All patients underwent oxygen therapy during flight, and all but one patient received the administration of lactate Ringer fluid. The subjective symptoms of eight of 28 subjects improved after the flight. The range of all flights under 300 m above sea level. There were no significant differences between the values obtained before and after the flight for Glasgow coma scale, blood pressure, and heart rate. Concerning the SpO2, statistically significant improvements were noted after the flight (96.2 ± 0.9% versus 97.3 ± 0.7%). There were no relationships between an improvement in subjective symptoms and the SpO2. Conclusion: Improvements in the subjective symptoms and/or SpO2 of patients with DCI may be observed when the patient is transported via HEMS under flights less than 300 m in height with the administration of oxygen and fluids. PMID:25709249

  16. Ascent and decompression of viscous vesicular magma in a volcanic conduit

    NASA Astrophysics Data System (ADS)

    Massol, HéLèNe; Jaupart, Claude; Pepper, Darrell W.

    2001-01-01

    During eruption, lava domes and flows may become unstable and generate dangerous explosions. Fossil lava-filled eruption conduits and ancient lava flows are often characterized by complex internal variations of gas content. These observations indicate a need for accurate predictions of the distribution of gas content and bubble pressure in an eruption conduit. Bubbly magma behaves as a compressible viscous liquid involving three different pressures: those of the gas and magma phases, and that of the exterior. To solve for these three different pressures, one must account for expansion in all directions and hence for both horizontal and vertical velocity components. We present a new two-dimensional finite element numerical code to solve for the flow of bubbly magma. Even with small dissolved water concentrations, gas overpressures may reach values larger than 1 MPa at a volcanic vent. For constant viscosity the magnitude of gas overpressure does not depend on magma viscosity and increases with the conduit radius and magma chamber pressure. In the conduit and at the vent, there are large horizontal variations of gas pressure and hence of exsolved water content. Such variations depend on decompression rate and are sensitive to the "exit" boundary conditions for the flow. For zero horizontal shear stress at the vent, relevant to lava flows spreading horizontally at the surface, the largest gas overpressures, and hence the smallest exsolved gas contents, are achieved at the conduit walls. For zero horizontal velocity at the vent, corresponding to a plug-like eruption through a preexisting lava dome or to spine growth, gas overpressures are largest at the center of the vent. The magnitude of gas overpressure is sensitive to changes of magma viscosity induced by degassing and to shallow expansion conditions in conduits with depth-dependent radii.

  17. Early Decompression following Cervical Spinal Cord Injury: Examining the Process of Care from Accident Scene to Surgery.

    PubMed

    Battistuzzo, Camila R; Armstrong, Alex; Clark, Jillian; Worley, Laura; Sharwood, Lisa; Lin, Peny; Rooke, Gareth; Skeers, Peta; Nolan, Sherilyn; Geraghty, Timothy; Nunn, Andrew; Brown, Doug J; Hill, Steven; Alexander, Janette; Millard, Melinda; Cox, Susan F; Rao, Sudhakar; Watts, Ann; Goods, Louise; Allison, Garry T; Agostinello, Jacqui; Cameron, Peter A; Mosley, Ian; Liew, Susan M; Geddes, Tom; Middleton, James; Buchanan, John; Rosenfeld, Jeffrey V; Bernard, Stephen; Atresh, Sridhar; Patel, Alpesh; Schouten, Rowan; Freeman, Brian J C; Dunlop, Sarah A; Batchelor, Peter E

    2016-06-15

    Early decompression may improve neurological outcome after spinal cord injury (SCI), but is often difficult to achieve because of logistical issues. The aims of this study were to 1) determine the time to decompression in cases of isolated cervical SCI in Australia and New Zealand and 2) determine where substantial delays occur as patients move from the accident scene to surgery. Data were extracted from medical records of patients aged 15-70 years with C3-T1 traumatic SCI between 2010 and 2013. A total of 192 patients were included. The median time from accident scene to decompression was 21 h, with the fastest times associated with closed reduction (6 h). A significant decrease in the time to decompression occurred from 2010 (31 h) to 2013 (19 h, p = 0.008). Patients undergoing direct surgical hospital admission had a significantly lower time to decompression, compared with patients undergoing pre-surgical hospital admission (12 h vs. 26 h, p < 0.0001). Medical stabilization and radiological investigation appeared not to influence the timing of surgery. The time taken to organize the operating theater following surgical hospital admission was a further factor delaying decompression (12.5 h). There was a relationship between the timing of decompression and the proportion of patients demonstrating substantial recovery (2-3 American Spinal Injury Association Impairment Scale grades). In conclusion, the time of cervical spine decompression markedly improved over the study period. Neurological recovery appeared to be promoted by rapid decompression. Direct surgical hospital admission, rapid organization of theater, and where possible, use of closed reduction, are likely to be effective strategies to reduce the time to decompression. PMID:26650510

  18. THE EXTREME HOSTS OF EXTREME SUPERNOVAE

    SciTech Connect

    Neill, James D.; Quimby, Robert; Ofek, Eran; Wyder, Ted K.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Sullivan, Mark; Gal-Yam, Avishay; Howell, D. Andrew; Nugent, Peter; Seibert, Mark; Overzier, Roderik; Neff, Susan G.; Schiminovich, David; Bianchi, Luciana; Donas, Jose; Heckman, Timothy M.

    2011-01-20

    We use GALEX ultraviolet (UV) and optical integrated photometry of the hosts of 17 luminous supernovae (LSNe, having peak M{sub V} < -21) and compare them to a sample of 26, 000 galaxies from a cross-match between the SDSS DR4 spectral catalog and GALEX interim release 1.1. We place the LSN hosts on the galaxy NUV - r versus M{sub r} color-magnitude diagram (CMD) with the larger sample to illustrate how extreme they are. The LSN hosts appear to favor low-density regions of the galaxy CMD falling on the blue edge of the blue cloud toward the low-luminosity end. From the UV-optical photometry, we estimate the star formation history of the LSN hosts. The hosts have moderately low star formation rates (SFRs) and low stellar masses (M{sub *}) resulting in high specific star formation rates (sSFR). Compared with the larger sample, the LSN hosts occupy low-density regions of a diagram plotting sSFR versus M{sub *} in the area having higher sSFR and lower M{sub *}. This preference for low M{sub *}, high sSFR hosts implies that the LSNe are produced by an effect having to do with their local environment. The correlation of mass with metallicity suggests that perhaps wind-driven mass loss is the factor that prevents LSNe from arising in higher-mass, higher-metallicity hosts. The massive progenitors of the LSNe (>100 M{sub sun}), by appearing in low-SFR hosts, are potential tests for theories of the initial mass function that limit the maximum mass of a star based on the SFR.

  19. Effects of a patent foramen ovale on arterial saturation during exercise and on cardiovascular responses to deep breathing, Valsalva manoeuvre, and passive tilt: relation to history of decompression illness in divers.

    PubMed Central

    Wilmshurst, P. T.; Treacher, D. F.; Crowther, A.; Smith, S. E.

    1994-01-01

    OBJECTIVE--To determine whether the presence of a patent foramen ovale could result in significant arterial desaturation and affect the responses of heart rate and blood pressure to physiological manoeuvres and to determine whether responses differed between those with and those without prior clinical events associated with a patent foramen ovale. DESIGN--Blind controlled study. SETTING--Teaching hospital. PATIENTS--Divers with a large patent foramen ovale shown by contrast echocardiography and divided into those who had neurological decompression illness that started within 30 minutes of surfacing (group 1), those who had no history of decompression illness (group 2), and age and sex matched control divers who had no evidence of intracardiac shunts (group 3). MAIN OUTCOME MEASURES--The change in percentage haemoglobin oxygen saturation during treadmill exercise and the response of heart rate and blood pressure to physiological manoeuvres. RESULTS--There were no significant differences between the three groups but two divers in group 1 showed clinically important desaturation during exercise and unusual blood pressure and heart rate responses to passive tilt. These divers were notable for having the greatest number of episodes and the most severe single episode of spinal cord decompression illness. CONCLUSION--A large patent foramen ovale may be associated with clinically significant arterial desaturation and unusual responses of heart rate and blood pressure in some healthy subjects. PMID:8142190

  20. Case Report: Acute obstructive hydrocephalus associated with infratentorial extra-axial fluid collection following foramen magnum decompression and durotomy for Chiari malformation type I

    PubMed Central

    Munakomi, Sunil; Bhattarai, Binod; Chaudhary, Pramod

    2016-01-01

    Acute obstructive hydrocephalus due to infratentorial extra-axial fluid collection (EAFC) is an extremely rare complication of foramen magnum decompression (FMD) and durotomy for Chiari malformation type I. Presence of infratentorial  EAFC invariably causes obstruction at the level of the fourth ventricle or aqueduct of Silvius, thereby indicating its definitive role in hydrocephalus. Pathogenesis of EAFC is said to be a local arachnoid tear as a result of durotomy, as this complication is not described in FMD without durotomy. Controversy exists in management. Usually EAFC is said to resolve with conservative management; so hydrocephalus doesn’t require treatment. However, in this case EAFC was progressive and ventriculo-peritoneal shunting (VPS) was needed for managing progressive and symptomatic hydrocephalus. PMID:27303624

  1. Posterior auricular approach for decompression and drainage of superficial temporal space infections of odontogenic origin.

    PubMed

    Thakur, Gagan; Bhargava, Darpan; Thomas, Shaji; Arora, Punitpal Singh

    2015-03-01

    Involvement of superficial temporal space secondary to odontogenic infections of the maxillary and mandibular teeth is not uncommon. Usually, infections of the temporal space are drained via temporal approach. Authors propose a new approach for decompression and drainage of superficial temporal space which offers an advantage of dependent drainage and hidden scar. PMID:25729236

  2. Efficacy of Surgical Decompression in the Setting of Complete Thoracic Spinal Cord Injury

    PubMed Central

    Rahimi-Movaghar, Vafa

    2005-01-01

    Background/Objective: An assessment of neurological improvement after surgical intervention in the setting of traumatic thoracic spinal cord injury (SCI). Methods: A retrospective evaluation of a nonconsecutive cohort of patients with a thoracic SCI from T2 to T11. The analysis included a total of 12 eligible patients. The neurologic and functional outcomes were recorded from the acute hospital admission to the most recent follow-up. Data included patient age, level of injury, neurologic examination according to the Frankel grading system, the performance of surgery, and the mechanism of the time-related SCI decompression. Results: All patients had a complete thoracic SCI. The median interval from injury to surgery was 11 days (range, 1–36 days). Decompression, bone fusion, and instrumentation were the most common surgical procedures performed. The median length of follow-up was 18 months after surgery (range, 9–132 months). Motor functional improvement was seen in 1 patient (Frankel A to C). Conclusion: Surgical decompression and fusion imparts no apparent benefit in terms of neurologic improvement (spinal cord) in the setting of a complete traumatic thoracic SCI. To better define the role of surgical decompression and stabilization in the setting of a complete SCI, randomized, controlled, prospective studies are necessary. PMID:16869088

  3. In vitro and in vivo fall of intradiscal pressure with laser disc decompression.

    PubMed

    Choy, D S; Diwan, S

    1992-12-01

    In vitro and in vivo measurements of intradiscal pressure under load and without load, respectively, before and after laser ablation of small volumes of nucleus pulposus revealed significant falls of intradiscal pressure. This is the basic principle underlying percutaneous laser disc decompression (PLDD). PMID:10148211

  4. Obtuse-angled Laminotomy as a Modification of Multilevel Laminectomy for Spinal Cord Decompression.

    PubMed

    Jhas, Sumit; Pirouzmand, Farhad

    2016-03-01

    The purpose of this note is to describe an obtuse-angled laminotomy of C7 during cervical decompression that aims to preserve cervicothoracic junction stability and potentially reduce pain. Cervical spondylotic myelopathy can result from degenerative cervical spinal disease including, herniated disk material, osteophytes, redundant ligamentum flavum, or ossification of the posterior longitudinal ligament. Surgical intervention for multilevel myelopathy aims to decompress the spinal cord and maintain stability of the cervical spine. Multilevel laminectomy is traditionally used when degenerative changes affect 3 or more levels and when there is primarily dorsal compressive disease. Traditional laminectomy can result in instability and kyphosis. The C7 lamina can be particularly vulnerable given the location at cervicothoracic junction. We describe an obtuse-angled laminotomy for the most caudal lamina in a planned decompression. This lamina is left attached to ligamentum nuchea, adjacent fascia, and paravertebral muscles. Only the base of spinous process and ventral portion of lamina's cortical and cancellous bone are removed in an obtuse angle through the opening. This variation is aimed to preserve as much of the cervical stability while still achieving the goal of decompression. PMID:26889986

  5. Complications of non-endoscopic percutaneous laser disc decompression and nucleotomy with the neodymium: YAG laser 1064 nm.

    PubMed

    Hellinger, J

    2004-10-01

    In this review, we discuss how nonendoscopic percutaneous laser disc decompression (PLDD) and nucleotomy, using the YAG laser 1064, now has reinforced itself as a minimally invasive procedure in discogenic, vertebral pain syndromes, created by bulging, protrusions, and contained and uncontained extrusions in all areas of the spine. The rate of complication is an important criterion of the application of this new method. 3377 patients were treated with this method in the period of November 11, 1989 to April 30, 2002. While 356 patients' cervical spine was operated on, a further 38 patients had their thoracic spine operated on. Six weeks later, a prospective, consecutive control followed with an uninterrupted recording. Subsequently, all complications that occurred in this time frame were recorded. A comparison was carried out between the complication rate as covered by the literature of other intradiscal percutaneous methods and open disc surgery. Using the Nd-YAG laser 1064 nm, PLDD is generally evaluated with a complication rate of 0.5%. In the cervical spine area, the complication rate was 1.0%. No significant complications followed the thoracic intervention. In comparison to figures suggested by the relevant literature regarding possible complications with other procedures, this particular procedure is relative risk-free. In conjunction with the satisfying results regarding pain and paralysis removal, the extraordinarily low complication density of Nd-YAG PLDD culminates in the recommendation that the procedure should be applied to patients who are between unsuccessful conservative therapy and other operative methods. PMID:15671715

  6. Exercise before and after SCUBA diving and the role of cellular microparticles in decompression stress.

    PubMed

    Madden, Dennis; Thom, Stephen R; Dujic, Zeljko

    2016-01-01

    Risk in SCUBA diving is often associated with the presence of gas bubbles in the venous circulation formed during decompression. Although it has been demonstrated time-after-time that, while venous gas emboli (VGE) often accompany decompression sickness (DCS), they are also frequently observed in high quantities in asymptomatic divers following even mild recreational dive profiles. Despite this VGE are commonly utilized as a quantifiable marker of the potential for an individual to develop DCS. Certain interventions such as exercise, antioxidant supplements, vibration, and hydration appear to impact VGE production and the decompression process. However promising these procedures may seem, the data are not yet conclusive enough to warrant changes in decompression procedure, possibly suggesting a component of individual response. We hypothesize that the impact of exercise varies widely in individuals and once tested, recommendations can be made that will reduce individual decompression stress and possibly the incidence of DCS. The understanding of physiological adaptations to diving stress can be applied in different diseases that include endothelial dysfunction and microparticle (MP) production. Exercise before diving is viewed by some as a protective form of preconditioning because some studies have shown that it reduces VGE quantity. We propose that MP production and clearance might be a part of this mechanism. Exercise after diving appears to impact the risk of adverse events as well. Research suggests that the arterialization of VGE presents a greater risk for DCS than when emboli are eliminated by the pulmonary circuit before they have a chance to crossover. Laboratory studies have demonstrated that exercise increases the incidence of crossover likely through extra-cardiac mechanisms such as intrapulmonary arterial-venous anastomoses (IPAVAs). This effect of exercise has been repeated in the field with divers demonstrating a direct relationship between exercise

  7. Predictions from a mathematical model of decompression compared to Doppler scores.

    PubMed

    Flook, Valerie

    2011-01-01

    This paper describes an attempt to calibrate a mathematical model that predicts the extent of bubble formation in both the tissue and blood of subjects experiencing decompression from a hyperbaric exposure. The model combines an inert gas dynamics model for uptake and elimination of inert anesthetic gases with a simple model of bubble dynamics in perfused tissues. The calibration has been carried out using the model prediction for volume of free gas (bubbles) as microl/ml in central venous blood and relating this to Doppler scores recorded at the end of hyperbaric exposures. More than 1,000 Doppler scores have been compared with the model predictions. Discriminant analysis has been used to determine the cut-points between scores below a certain level and all scores at or above that level. This allows each prediction from the model to be equated to a particular pattern of bubble scores. The predictions from the model are thus given a context against the more familiar Doppler scores as a means of evaluating decompression stress. It is thus possible to use the mathematical model to evaluate decompression stress of a hyperbaric exposure in terms of the predicted volume of gas that will form into bubb