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Sample records for extreme decompression rates

  1. 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

  2. Use of heart rate monitoring for an individualized and time-variant decompression model.

    PubMed

    Gutvik, Christian R; Wisløff, Ulrik; Brubakk, Alf O

    2010-11-01

    Individual differences, physiological pre-conditions and in-dive conditions like workload and body temperature have been known to influence bubble formation and risk of decompression sickness in diving. Despite this fact, such effects are currently omitted from the decompression algorithms and tables that are aiding the divers. There is an apparent need to expand the modeling beyond depth and time to increase safety and efficiency of diving. The present paper outlines a mathematical model for how heart rate monitoring in combination with individual parameters can be used to obtain a customized and time-variant decompression model. We suggest that this can cover some of the individual differences and dive conditions that are affecting bubble formation. The model is demonstrated in combination with the previously published Copernicus decompression model, and is suitable for implementation in dive computers and post dive simulation software for more accurate risk analysis. PMID:20577757

  3. Magma decompression rates during explosive eruptions of Kīlauea volcano, Hawaii, recorded by melt embayments

    NASA Astrophysics Data System (ADS)

    Ferguson, David J.; Gonnermann, Helge M.; Ruprecht, Philipp; Plank, Terry; Hauri, Erik H.; Houghton, Bruce F.; Swanson, Donald A.

    2016-10-01

    The decompression rate of magma as it ascends during volcanic eruptions is an important but poorly constrained parameter that controls many of the processes that influence eruptive behavior. In this study, we quantify decompression rates for basaltic magmas using volatile diffusion in olivine-hosted melt tubes (embayments) for three contrasting eruptions of Kīlauea volcano, Hawaii. Incomplete exsolution of H2O, CO2, and S from the embayment melts during eruptive ascent creates diffusion profiles that can be measured using microanalytical techniques, and then modeled to infer the average decompression rate. We obtain average rates of ~0.05-0.45 MPa s-1 for eruptions ranging from Hawaiian style fountains to basaltic subplinian, with the more intense eruptions having higher rates. The ascent timescales for these magmas vary from around ~5 to ~36 min from depths of ~2 to ~4 km, respectively. Decompression-exsolution models based on the embayment data also allow for an estimate of the mass fraction of pre-existing exsolved volatiles within the magma body. In the eruptions studied, this varies from 0.1 to 3.2 wt% but does not appear to be the key control on eruptive intensity. Our results do not support a direct link between the concentration of pre-eruptive volatiles and eruptive intensity; rather, they suggest that for these eruptions, decompression rates are proportional to independent estimates of mass discharge rate. Although the intensity of eruptions is defined by the discharge rate, based on the currently available dataset of embayment analyses, it does not appear to scale linearly with average decompression rate. This study demonstrates the utility of the embayment method for providing quantitative constraints on magma ascent during explosive basaltic eruptions.

  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. The rate of gas-bubble growth in tissue under decompression. Mathematical modelling.

    PubMed

    Kislyakov YuYa; Kopyltsov, A V

    1988-03-01

    A mathematical model simulating the formation of gas bubbles in biological tissues under decompression is presented. It is written as a system of partial differential equations solved on a computer. For the nitrogen-oxygen gas mixture, used for respiration in deep-water immersions, the effects of the physico-chemical properties of the gases, the magnitude of pressure differentials and the density of bubble-formation centres on the bubble size and rate of growth were studied. It is shown that in the case of drastic pressure differentials the formation of bubbles capable of producing microcirculatory disturbances is accomplished within a few seconds.

  7. 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.

  8. Per-capita claims rates for decompression sickness among insured Divers Alert Network members.

    PubMed

    Denoble, Petar J; Ranapurwala, Shabbar I; Vaithiyanathan, Panchabi; Clarke, Richard E; Vann, Richard D

    2012-01-01

    Decompression sickness (DCS) in recreational diving is a rare and usually self-limiting injury, but permanent disability can occur. Incidence rate estimates are difficult to establish because the number of divers at risk is usually unknown in population samples with well-documented DCS. We estimated the annual per-capita DCS incidence rates for 2000-2007 based on insurance claims submitted by members of the Divers Alert Network (DAN), Durham, N.C., with dive accident insurance. The overall per-capita DCS claims rate (DCR) was 20.5 per 10,000 member-years. Based on the age-adjusted DCR, males submitted 28% more claims than females. Male-to-female difference was greatest between 35 and 40 years of age and disappeared by the mid-50s. Highest rates were observed in the 30- to 39-year age category, after which DCR declined with increasing age. Highest yearly DCR was estimated in 2002. Insurance dropout rate was greater among those who had DCS in the first year of their insurance compared to those who did not have DCS in their first year.

  9. 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.

  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. 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

  12. 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.

  13. 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.

  14. 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.

  15. Extreme variations of air dose rates in east Fukushima.

    PubMed

    Akimoto, Kazuhiro

    2015-11-01

    This report analyses the data of air (ambient) dose rates measured at 164 points in eastern Fukushima during a period of half a year after 10 June 2011. It is found that at some locations the values decreased or increased extraordinarily although on average the overall dose rates decreased significantly faster than the theoretically predicted rate. Among them the nine most extreme points are selected and analysed. It is found that behind these extraordinary behaviours of air dose rates there exists the combination of wind/rain and artificial structures such as sloped pavements.

  16. Solidification at the High and Low Rate Extreme

    SciTech Connect

    Meco, Halim

    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

  17. 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

  18. Endothelial dysfunction correlates with decompression bubbles in rats.

    PubMed

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

    2016-09-12

    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.

  19. 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

  20. Regional intensity of vascular care and lower extremity amputation rates

    PubMed Central

    Goodney, Philip P.; Holman, Kerianne; Henke, Peter K.; Travis, Lori L.; Dimick, Justin B.; Stukel, Therese A.; Fisher, Elliott. S.; Birkmeyer, John D.

    2013-01-01

    Objective To examine the relationship between the intensity of vascular care and population-based rate of major lower extremity amputation (above-or below-knee) from vascular disease. Background Because patient-level differences do not fully explain the variation in amputation rate across the United States, we hypothesized that variation in intensity of vascular care may also affect regional rates of amputation. Methods Intensity of vascular care was defined as the proportion of Medicare patients who underwent any vascular procedure in the year prior to amputation, calculated at the regional level (2003–2006), using the 306 hospital referral regions in the Dartmouth Atlas of Healthcare. We examined relationship between intensity of vascular care and major amputation rate, at the regional level, between 2007–2009. Results Amputation rates varied widely by region, from 1 to 27 per 10,000 Medicare patients. Compared to regions in the lowest quintile of amputation rate, patients in the highest quintile were commonly African American (50% versus 13%) and diabetic (38% versus 31%). Intensity of vascular care also varied across regions: fewer than 35% of patients underwent revascularization in the lowest quintile of intensity, while nearly 60% of patients underwent revascularization in the highest quintile. Overall, there was an inverse correlation between intensity of vascular care and amputation rate ranging from R= −0.36 for outpatient diagnostic and therapeutic procedures, to R= −0.87 for inpatient surgical revascularizations. In analyses adjusting for patient characteristics and socioeconomic status, patients in high vascular care regions were significantly less likely to undergo amputation without an antecedent attempt at revascularization (OR 0.37, 95% CI 0.34–0.37, p<0.001). Conclusions The intensity of vascular care provided to patients at risk for amputation varies, and regions with the most intensive vascular care have the lowest amputation rate

  1. MRI in decompression illness.

    PubMed

    Hierholzer, J; Tempka, A; Stroszczynski, C; Amodio, F; Hosten, N; Haas, J; Felix, R

    2000-05-01

    We report a case of decompression illness in which the patient developed paraparesis during scuba diving after rapid ascent. MRI of the spine revealed a focal intramedullary lesion consistent with the symptoms. The pathophysiological and radiological aspects of spinal decompression illness are discussed.

  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. 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.

  4. 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.

  5. Endothelial dysfunction correlates with decompression bubbles in rats

    PubMed Central

    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

  6. 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.

  7. 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

  8. 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

  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. Metabolism and decompression tolerance of scavenging lysianassoid deep-sea amphipods

    NASA Astrophysics Data System (ADS)

    Treude, Tina; Janßen, Felix; Queisser, Wolfgang; Witte, Ursula

    2002-07-01

    Respiration, ammonia excretion and decompression tolerance were studied in several species of lysianassoid amphipods captured at four stations in the deep Arabian Sea with an isolated trap maintaining them at in situ temperature. The amphipods were decompressed from their ambient to atmospheric pressure during recovery. Six amphipods, belonging to the species Eurythenes gryllus, Paralicella caperesca and Abyssorchomene abyssorum, survived decompression from depths between 1920 and 4420 m. The physiological condition of these specimens was good inferred by the fact that their swimming and resting behaviour appeared normal, they reacted to disturbance by light and vibration, and were able to ingest food to maintain full guts. Most of the amphipods (421 individuals), however, were recovered dead, which allows information about their decompression tolerance and their vertical migration ability to be deduced. Weight-specific respiration rates of the deep-sea amphipods that were fed prior to the experiments were not lower than in shallow-water amphipods living at similar temperatures. Differences in respiration rates between the specimens are discussed with regard to body size, species specificity and food supply. Weight-specific ammonia excretion rates were extremely high when compared with shallow-water relatives, indicating a capability for rapid digestion. This may be an adaptation to the unpredictable food supply in the deep sea as it enables the amphipod to empty its digestive tract quickly, thus making it available for additional food. Rapid digestion also enables the animals to regain mobility soon after feeding, permitting them to move to new food sources.

  11. Inner ear decompression sickness.

    PubMed

    Farmer, J C; Thomas, W G; Youngblood, D G; Bennett, P B

    1976-09-01

    With recent increases in commercial, military, and sport diving to deeper depths, inner ear injuries during such exposures have been encountered more frequently and noted during several phases of diving: during compression, at stable deep depths, with excessive noise exposure in diving, and during decompression. The pathophysiology of these injuries differs, depending upon the phase of diving in which the injuries occur. In this report, 23 cases of hearing loss, tinnitus, and/or vertigo occurring during or shortly after decompression are presented. Thirteen of these cases occurred in helium-oxygen dives involving a change to air during the latter stages of decompression. A significant correlation is present between prompt recompression treatment, relief of symptoms, and lack of residual deficits. Current knowledge indicates that the management of otologic decompression sickness should include: 1. prompt recompression to at least 99 feet deeper than the symptom onset depth; 2. recompression using the previous helium-oxygen mixture when the injuries occur during or shortly after a switch from helium-oxygen to air during the latter stages of decompression; 3. the use of parenteral diazepam for symptom relief and cyclic inhalations of oxygen enriched treatment gases; and 4. the avoidance of further diving by divers who exhibit permanent inner ear injuries after the acute symptoms have subsided.

  12. 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.

  13. Orbital decompression for Graves' orbitopathy in England

    PubMed Central

    Perros, P; Chandler, T; Dayan, C M; Dickinson, A J; Foley, P; Hickey, J; MacEwen, C J; Lazarus, J H; McLaren, J; Rose, G E; Uddin, J M; Vaidya, B

    2012-01-01

    Aims The purpose of this study was to obtain data on orbital decompression procedures performed in England, classed by hospital and locality, to evaluate regional variation in care. Methods Data on orbital decompression taking place in England over a 2-year period between 2007 and 2009 were derived from CHKS Ltd and analysed by the hospital and primary care trust. Results and conclusions In all, 44% of these operations took place in hospitals with an annual workload of 10 or fewer procedures. Analysis of the same data by primary care trust suggests an almost 30-fold variance in the rates of decompression performed per unit population. Expertise available to patients with Graves' orbitopathy and rates of referral for specialist care in England appears to vary significantly by geographic location. These data, along with other outcome measures, will provide a baseline by which progress can be judged. PMID:22157920

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Decompressive laparotomy for abdominal compartment syndrome

    PubMed Central

    Kimball, E.; Malbrain, M.; Nesbitt, I.; Cohen, J.; Kaloiani, V.; Ivatury, R.; Mone, M.; Debergh, D.; Björck, M.

    2016-01-01

    Background The effect of decompressive laparotomy on outcomes in patients with abdominal compartment syndrome has been poorly investigated. The aim of this prospective cohort study was to describe the effect of decompressive laparotomy for abdominal compartment syndrome on organ function and outcomes. Methods This was a prospective cohort study in adult patients who underwent decompressive laparotomy for abdominal compartment syndrome. The primary endpoints were 28‐day and 1‐year all‐cause mortality. Changes in intra‐abdominal pressure (IAP) and organ function, and laparotomy‐related morbidity were secondary endpoints. Results Thirty‐three patients were included in the study (20 men). Twenty‐seven patients were surgical admissions treated for abdominal conditions. The median (i.q.r.) Acute Physiology And Chronic Health Evaluation (APACHE) II score was 26 (20–32). Median IAP was 23 (21–27) mmHg before decompressive laparotomy, decreasing to 12 (9–15), 13 (8–17), 12 (9–15) and 12 (9–14) mmHg after 2, 6, 24 and 72 h. Decompressive laparotomy significantly improved oxygenation and urinary output. Survivors showed improvement in organ function scores, but non‐survivors did not. Fourteen complications related to the procedure developed in eight of the 33 patients. The abdomen could be closed primarily in 18 patients. The overall 28‐day mortality rate was 36 per cent (12 of 33), which increased to 55 per cent (18 patients) at 1 year. Non‐survivors were no different from survivors, except that they tended to be older and on mechanical ventilation. Conclusion Decompressive laparotomy reduced IAP and had an immediate effect on organ function. It should be considered in patients with abdominal compartment syndrome. PMID:26891380

  19. Horizon instability of extremal Kerr black holes: Nonaxisymmetric modes and enhanced growth rate

    NASA Astrophysics Data System (ADS)

    Casals, Marc; Gralla, Samuel E.; Zimmerman, Peter

    2016-09-01

    We show that the horizon instability of the extremal Kerr black hole is associated with a singular branch point in the Green function at the superradiant bound frequency. We study generic initial data supported away from the horizon and find an enhanced growth rate due to nonaxisymmetric modes. The growth is controlled by the conformal weight h of each mode. We speculate on connections to near-extremal black holes and holographic duality.

  20. Characterization and outcomes of repeat orbital decompression for thyroid-associated orbitopathy.

    PubMed

    Zhang-Nunes, Sandy X; Dang, Sabin; Garneau, Helene Chokron; Hwang, Catherine; Isaacs, David; Chang, Shu-Hong; Goldberg, Robert

    2015-04-01

    Orbital decompression for thyroid-associated orbitopathy (TAO) is commonly performed for disfiguring proptosis, congestion, and optic neuropathy. Although one decompression typically achieves goals, a small percentage requires repeat decompression. We performed a 10-year retrospective chart review of all orbital decompressions for TAO at a single tertiary referral institution. Four-hundred and ninety-five orbits (330 patients) were decompressed for TAO, with 45 orbits (37 patients) requiring repeat decompression. We reviewed the repeat cases for indications, clinical activity scores, approach, walls decompressed, and outcomes. Nine percent of orbits required repeat decompression for proptosis (70%), optic neuropathy (25%) or congestion (45%). Sixty-four percent were for recurrence of disease, 36% were for suboptimal decompression. Three incisional approaches were used: lateral upper eyelid crease, inferior transconjunctival, and transcaruncular, with inferior transconjunctival being most common. Of the three walls removed, deep lateral, inferior, and medial, the deep lateral wall was most common (51%). A repeat lateral decompression was the most frequent pattern. Of 37 patients requiring repeat decompression, 40% had diplopia prior to repeat, and an additional 24% developed diplopia after the repeat. Whereas previous studies published by our group cited only 2.6% of deep lateral wall orbital decompressions leading to new-onset primary gaze diplopia, repeat orbital decompressions have a much higher rate of post-operative diplopia. The new onset primary gaze diplopia after repeat decompression group had a higher average preoperative CAS (3.3 vs. 2.4, p < 0.01), higher mean blood loss (56 vs. 19 mL, p = 0.04), more frequent medial wall decompressions (47% vs. 29%, p = 0.33), and greater proptosis reduction (2.4 vs. 1.7 mm, p = 0.24).

  1. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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-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-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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Early Decompression (< 8 h) after Traumatic Cervical Spinal Cord Injury Improves Functional Outcome as Assessed by Spinal Cord Independence Measure after One Year.

    PubMed

    Grassner, Lukas; Wutte, Christof; Klein, Barbara; Mach, Orpheus; Riesner, Silvie; Panzer, Stephanie; Vogel, Matthias; Bühren, Volker; Strowitzki, Martin; Vastmans, Jan; Maier, Doris

    2016-09-15

    There is an ongoing controversy about the optimal timing for surgical decompression after acute traumatic cervical spinal cord injury (SCI). For this reason, we performed a retrospective study of patients who were operated on after traumatic cervical SCI at the Trauma Center Murnau, Germany, and who met inclusion as well as exclusion criteria (n = 70 patients). Follow-up data were collected prospectively according to the European Multicenter Study about Spinal Cord Injury (EMSCI) protocol over a period of 1 year. Early decompression was defined as within the first 8 h after the insult (n = 35 patients). Primary outcome was the difference in the SCIM (Spinal Cord Independence Measure) 1 year after the trauma. After the follow-up period, patients who were decompressed earlier had a significantly higher SCIM difference (45.8 vs. 27.1, p < 0.005). A regression analysis showed that timing of decompression, age, as well as basal AIS (American Spinal Injury Association Impairment Scale) and basal SCIM scores were independent predictors for a better functional outcome (SCIM). Further, patients from the early decompression group had better AIS grades (p < 0.006) and a higher AIS conversion rate (p < 0.029). Additionally, this cohort also had a better total motor performance as well as upper extremity motor function after 1 year (p < 0.025 and p < 0.002). The motor and neurological levels of patients who were operated on within 8 h were significantly more caudal (p < 0.003 and p < 0.014) after 1 year. The present study suggests that early decompression after traumatic cervical SCI might have a positive impact on the functional and neurological outcome of affected individuals.

  12. 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.

  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. 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/).

  15. 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.

  16. 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.

  17. [Determination of divers' resistance to decompression gas formation].

    PubMed

    Miasnikov, A An; Shitov, A Iu; Chernov, V I; Zhil'tsova, I I; Iur'ev, A Iu; Miasnikov, A Al

    2013-02-01

    The aim of the study was to determine the correlation between the state of the individual functions of the organism and the intensity of decompression venous gas embolism after high air pressure exposure. The analysis of the guidelines defining the procedure of divers' medical examination was made and 320 divers were surveyed. Indices of the divers' central nervous and cardiovascular systems were measured before and after their immersion into a hyperbaric chamber. The study found that the conduct divers' on-resistance to unfavorable scuba dive should be provided by the military-medical commission, so the position of diving doctor should be put to it staff. It was revealed that the rate of simple visual-motor reaction, measured before the diving can serve as an indicator of human resistance to decompression gassing. The formula for determining the stability of decompression gassing of men aged 20-30 years in terms of state of organism functions was proposed.

  18. 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.

  19. 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.

  20. Bubble coalescence in rhyolitic melts during decompression from high pressure

    NASA Astrophysics Data System (ADS)

    Gardner, James E.

    2007-10-01

    When bubbly magma becomes permeable, its eruptive behavior is altered and gases are released that may be detected for monitoring. Permeability is produced by bubbles interacting and coalescing, but can be changed if the magmatic foam deforms. This study investigates how decompression rate and viscosity influence bubble coalescence through a series of hydrothermal experiments, in which bubble-bearing rhyolite is decompressed at temperatures ranging from 725° to 875 °C, producing viscosities of ˜ 10 5-10 7 Pa s. Most decompressions are at steady rates of 0.0064 to 0.025 MPa s - 1 , but a few are at rates that increase as pressure decreases; all are slow enough to maintain equilibrium as pressure drops. Bubble interaction and coalescence is recorded by variations in bubble sizes and bubble number density ( NB), and is found to be influenced strongly by melt viscosity, with more time needed for bubbles to coalesce as viscosity increases, yet the extent of coalescence appears limited by the distance between bubbles. The extent of coalescence is also influenced by decompression rate, with bubble interactions in lower viscosity melts being suppressed at decompression rates comparable to those expected for Plinian eruptions. In contrast, rates equivalent to lava dome extrusions are too slow to hinder bubble interactions from extensively altering the bubble population in lower viscosity melts. Deformation of coalescing permeable foam was observed when NB is on order of ˜ 10 5 cm - 3 , but not when it was on order of ˜ 10 7 cm - 3 , suggesting that magma degassing could be influenced by how many bubbles nucleate in the first place.

  1. 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.

  2. [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.

  3. 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.

  4. 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

  5. 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

  6. Mechanism of lung damage in explosive decompression.

    PubMed

    Topliff, E D

    1976-05-01

    It is known that pressure equalization via the trachea may diminish or prevent lung damage in explosive decompression. In this report, evidence is presented which demonstrates that closure of the trachea does not affect lethality in mice exposed to maximally rapid decompression. This observation suggests that in maximally rapid decompression the lungs and thorax may be treated as a closed system to which Boyle's Law might be applicable. PMID:1275842

  7. 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

  8. [Orbital decompression for Graves' ophthalmopathy].

    PubMed

    Boulétreau, P; Breton, P; Freidel, M

    2005-04-01

    Graves' ophthalmopathy is a complex orbital condition with a controversial pathogenesis. It is the clinical expression of a discordance between the inextensible orbit and hypertrophic muscular and fatty elements within the orbit responding to immunological stimulation. The relationship between the orbital and its content can be improved by surgical expansion which increases the useful volume of the orbit. This procedure can be combined with lipectomy to decrease the volume of the orbital contents. We briefly recall the history of surgical decompression techniques and present our experience with Graves' ophthalmopathy patients.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. '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.

  14. '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

  15. Bubble dynamics in perfused tissue undergoing decompression.

    PubMed

    Meisel, S; Nir, A; Kerem, D

    1981-02-01

    A mathematical model describing bubble dynamics in a perfused tissue undergoing decompression is presented, taking into account physical expansion and inward diffusion from surrounding supersaturated tissue as growth promoting factors and tissue gas elimination by perfusion, tissue elasticity, surface tension and inherent unsaturation as resolving driving forces. The expected behavior after a step reduction of pressure of a bubble initially existing in the tissue, displaying both growth and resolution has been demonstrated. A strong perfusion-dependence of bubble resolution time at low perfusion rates is apparent. The model can account for various exposure pressures and saturation fractions of any inert gas-tissue combination for which a set of physical and physiological parameters is available.

  16. 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

  17. 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.

  18. [Decompression sickness after diving and following flying].

    PubMed

    Laursen, S B; Grønfeldt, W; Jacobsen, E

    1999-07-26

    A case of delayed symptoms of decompression sickness (DCS) after diving and flying is reported. The diver presented with classical signs of type 2 DCS, probably caused by air travel 16 hours after SCUBA diving. Treatment with hyperbaric oxygen (HBO) in a decompression chamber was successful. Guidelines to prevent DCS for recreational divers who plan to fly after diving are presented.

  19. 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

  20. 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

  1. 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.…

  2. 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.

  3. Biomechanical evaluation of an interfacet joint decompression and stabilization system.

    PubMed

    Leasure, Jeremi M; Buckley, Jenni

    2014-07-01

    A majority of the middle-aged population exhibit cervical spondylosis that may require decompression and fusion of the affected level. Minimally invasive cervical fusion is an attractive option for decreasing operative time, morbidity, and mortality rates. A novel interfacet joint spacer (DTRAX facet screw system, Providence Medical) promises minimally invasive deployment resulting in decompression of the neuroforamen and interfacet fusion. The present study investigates the effectiveness of the device in minimizing intervertebral motion to promote fusion, decompression of the nerve root during bending activity, and performance of the implant to adhere to anatomy during repeated bending loads. We observed flexion, extension, lateral bending, and axial rotation resonant overshoot mode (ROM) in cadaver models of c-spine treated with the interfacet joint spacer (FJ spacer) as stand-alone and supplementing anterior plating. The FJ spacer was deployed bilaterally at single levels. Specimens were placed at the limit of ROM in flexion, extension, axial bending, and lateral bending. 3D images of the foramen were taken and postprocessed to quantify changes in foraminal area. Stand-alone spacer specimens were subjected to 30,000 cycles at 2 Hz of nonsimultaneous flexion-extension and lateral bending under compressive load and X-ray imaged at regular cycle intervals for quantitative measurements of device loosening. The stand-alone FJ spacer increased specimen stiffness in all directions except extension. 86% of all deployments resulted in some level of foraminal distraction. The rate of effective distraction was maintained in flexed, extended, and axially rotated postures. Two specimens demonstrated no detectable implant loosening (<0.25 mm). Three showed unilateral subclinical loosening (0.4 mm maximum), and one had subclinical loosening bilaterally (0.5 mm maximum). Results of our study are comparable to previous investigations into the stiffness of other stand

  4. 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

  5. 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 ...

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

    PubMed

    Bányai, László; Patthy, László

    2016-08-01

    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.

  7. 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

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

    PubMed

    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

  9. 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.

  10. 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

  11. 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).

  12. Crystal Nucleation and Growth in Mount Unzen Dacite Decompression Experiments

    NASA Astrophysics Data System (ADS)

    Almberg, L. D.; Larsen, J. F.; Eichelberger, J. C.

    2005-12-01

    Central to understanding eruption dynamics is the interplay of decompression and degassing, which triggers crystal nucleation and growth. Microlite and microphenocryst textures are an often-used tool to decipher the rates of magma ascent for specific eruptions. It is critical to determine the depth and time scale at which these processes take place to fully understand the system behavior. Conduit material retrieved from 1500 m depth from the USDP-4 at Mount Unzen, Japan provides a snap shot of a viscous magma en route to the surface and is a perfect counterpoint to compare with laboratory experiments under controlled P, T, and XH2O conditions. The core samples were identified as representing material from the 1991-1995 eruption based upon their elemental and isotopic composition and coincidence with a temperature maximum and alteration minimum (Nakada et al, ICDP Symposium, Potsdam, 2005). Three plagioclase crystal populations coexist in the spine emplaced at the conclusion of the eruption sequence in 1995, microlites (<20 μm), microphenocrysts (20-100 μm) and phenocrysts (>100 μm). Only phenocrysts and microlites are present in the samples extracted from 1500 m during drilling of the USDP-4 core. These textural differences are the focus of decompression experiments, with the purpose of replicating shallow level crystallization that may have occurred between 1500 m depth and the surface. It is possible that the microphenocrysts present in the dome lavas and absent in the conduit core could have formed at very shallow levels during magmatic ascent. Our experimental work delineates the role of decompression in controlling crystal size distributions in Unzen dacite, for comparison with the natural dome lavas and USDP-4 core samples. We conducted isothermal (870 ± 3°C) single and multi-step decompression experiments, equilibrated at 40 ± 3 MPa under water saturation and NNO conditions, and decompressed to 7.5 ± 0.5 MPa or 318 m depth. We ran such experiments for

  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. 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.

  15. 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.

  16. The Effects of Resonant Relaxation and Relativistic Precession on the Rate of Extreme Mass Ratio Inspirals

    NASA Astrophysics Data System (ADS)

    Gill, Michael; Miller, M.; Richardson, D.; Trenti, M.

    2010-01-01

    Extreme Mass Ratio Inspirals (EMRIs), during which a stellar-mass compact object in close orbit around a supermassive black hole gradually loses energy and angular momentum through the emission of gravitational radiation, are likely to be key sources of long-wavelength gravitational waves. Because the expected wavelengths fall in the band to which the Laser Interferometer Space Antenna will be most sensitive, these events should be detectable and thus provide a probe of the strong-field limit of gravity. Despite many years of study of EMRIs, there exist key uncertainties in relevant processes such as resonant relaxation. We present preliminary simulations of the center of a typical galaxy using a tree N-body code, and discuss the implications of our results for resonant relaxation in relativistic gravity. This work was funded in part by NASA grant NNX08AH29G.

  17. Interspinous process spacers versus traditional decompression for lumbar spinal stenosis: systematic review and meta-analysis

    PubMed Central

    Rao, Prashanth J.; Ball, Jonathon R.; Mobbs, Ralph J.

    2016-01-01

    Background Interspinous spacers are used in selected patients for the treatment of lumbar spinal stenosis. The uses of interspinous devices are still debated, with reports of significantly higher reoperation rates and unfavourable cost-effectiveness compared to traditional decompression techniques. Methods Six electronic databases were searched from their date of inception to December 2015. Relevant studies were identified using specific eligibility criteria and data was extracted and analyzed based on predefined primary and secondary endpoints. Results Eleven comparative studies were obtained for qualitative and quantitative assessment, data extraction and analysis. There was no significant difference in VAS back pain, leg pain or ODI scores for standalone interspinous process device (IPD) vs. bony decompression. However, standalone IPD was associated with lower surgical complications (4% vs. 8.7%, P=0.03) but higher long-term reoperation rates (23.7% vs. 8.5%, P<0.00001). IPD as an adjunct to decompression had comparable patient-reported scores, complications and reoperation rates to decompression alone. Conclusions Current evidence indicates no superiority for mid- to long-term patient-reported outcomes for IPD compared with traditional bony decompression, with lesser surgical complications but at the risk of significantly higher reoperation rates and costs.

  18. Interspinous process spacers versus traditional decompression for lumbar spinal stenosis: systematic review and meta-analysis

    PubMed Central

    Rao, Prashanth J.; Ball, Jonathon R.; Mobbs, Ralph J.

    2016-01-01

    Background Interspinous spacers are used in selected patients for the treatment of lumbar spinal stenosis. The uses of interspinous devices are still debated, with reports of significantly higher reoperation rates and unfavourable cost-effectiveness compared to traditional decompression techniques. Methods Six electronic databases were searched from their date of inception to December 2015. Relevant studies were identified using specific eligibility criteria and data was extracted and analyzed based on predefined primary and secondary endpoints. Results Eleven comparative studies were obtained for qualitative and quantitative assessment, data extraction and analysis. There was no significant difference in VAS back pain, leg pain or ODI scores for standalone interspinous process device (IPD) vs. bony decompression. However, standalone IPD was associated with lower surgical complications (4% vs. 8.7%, P=0.03) but higher long-term reoperation rates (23.7% vs. 8.5%, P<0.00001). IPD as an adjunct to decompression had comparable patient-reported scores, complications and reoperation rates to decompression alone. Conclusions Current evidence indicates no superiority for mid- to long-term patient-reported outcomes for IPD compared with traditional bony decompression, with lesser surgical complications but at the risk of significantly higher reoperation rates and costs. PMID:27683693

  19. 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

  20. 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.

  1. 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

  2. Decompression-Induced Crystallization of Hydrous Basalt

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Brooker, R. A.

    2014-12-01

    Decompression-induced crystallization of hydrous basalt during magma ascent from 1.5 kb (150 MPa) is quantified using isothermal decompression TZM experiments. The starting composition is a synthetic glass based on the 1921 Kilauea basalt, with 1% H2O added. In all cases, the liquidus phase is aluminous spinel, followed by clinopyroxene, then plagioclase. The plagioclase liquidus temperatures for isobaric (equilibrium) experiments range from 1175°C (at 1.5 kb) to 1217°C (at 200b), which are 35-75°C hotter than predicted by MELTS (Ghiorso & Sack 1995). Experiments were decompressed at 1kb/hr and quenched at 800, 400, 200, or 100b for three temperatures (1160°, 1150°, and 1140°C). Plagioclase crystals formed during decompression have long axes that range from less than 1 micron to 20 microns. Increasing decompression yields larger plagioclase crystal sizes and aspect ratios for experiments at equal temperatures. However, the number of crystals does not vary systematically, indicating that crystallization is dominated by growth rather than nucleation during decompression. Plagioclase compositions for experiments were measured with University of Bristol's Electron Microprobe and the Hyperprobe with Field Emission Gun. Plagioclase compositions from equilibrium experiments (An60-An80) span the range of those from decompression experiments (An60-An73). Equilibrium experiments generated higher An compositions at lower pressures (500b) than at higher pressure (1.5kb) but do not systematically vary with temperature. Variations in plagioclase compositions are minimal above H2O saturation (100-200°C, based on Papale et al., 2006). Below H2O saturation, An content decreases slightly, by approximately 4% An. One application of this work is better characterization of groundmass crystallization in hydrous basalt as it traverses the conduit during eruption. This work also provides a means of distinguishing groundmass plagioclase related to decompression from crystals

  3. Decompression Sickness in Sport Scuba Diving.

    PubMed

    Davis, J C; Bracker, M D

    1988-02-01

    In brief: Sport scuba diving in inland bodies of water has gained in popularity, and travelers to remote areas can fly home soon after a diving trip. Thus it is not unusual to see a case of decompression sickness in an emergency care facility, regardless of its location. Symptoms of decompression sickness may occur minutes or hours after diving with compressed gas. They include marked fatigue, pruritic mottled skin lesions, pain (joints, back, abdomen), weakness or paralysis of isolated or regional muscle groups, paresthesia, urinary retention, loss of anal sphincter control, dyspnea, coughing, vertigo, and substernal pain. Most patients respond quickly to prompt treatment in hyperbaric chambers, and the symptoms resolve completely.

  4. Significant Scoliosis Regression following Syringomyelia Decompression

    PubMed Central

    Mollano, Anthony V; Weinstein, Stuart L; Menezes, Arnold H

    2005-01-01

    We present the case of a 5-year-old boy presenting with a 54-degree scoliosis secondary to a Chiari I malformation with a holocord syringomyelia extending from C1 to T10. Neurosurgical treatment involved posterior fossa craniectomy with decompression, and partial C1 laminectomy. At follow-up 7 years later, at age 12, radiographs revealed only a 4-degree scoliosis, and follow-up MRI revealed a deflated syrinx. We report this case to reveal the most significant scoliosis regression seen in our experience that may occur in younger patients after neurosurgical syringomyelia decompression for Chiari I hindbrain herniation. PMID:16089074

  5. 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

  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. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Abdominal decompression chamber. 884.5225 Section... Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device used to reduce pressure on the pregnant patient's abdomen for the relief...

  8. 46 CFR 197.332 - PVHO-Decompression chambers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false PVHO-Decompression chambers. 197.332 Section 197.332... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.332 PVHO—Decompression chambers. Each decompression chamber must— (a) Meet the requirements of § 197.328; (b) Have internal...

  9. 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.

  10. 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

  11. 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

  12. [Ethmoidal mucocele after transpalpebral bony orbital decompression].

    PubMed

    Gire, J; Facon, F; Guigou, S; Fauquier, S; Malet, T

    2012-10-01

    We report a case of a late ethmoidal mucocele occurring after transpalpebral bony orbital decompression. A 39-year-old man presented with a recurrence of a right-sided proptosis without signs of orbital inflammation. The patient had undergone bilateral transpalpebral bony orbital decompression for dysthyroid orbitopathy 2 years prior. Orbital CT scan showed a large mucocele in the supero-lateral right ethmoidal sinus with lateral extension to the medial rectus. The patient was therefore referred to an ear, nose and throat (ENT) surgeon, who performed an anterior ethmoidectomy with marsupialization and drainage of the mucocele via an endoscopic approach. A complete postoperative resolution of proptosis was observed without recurrence of the mucocele to date, approximately 6 months postoperative. Sinus complications occurring after orbital decompression may include sinusitis, hematoma, imploding antrum syndrome and mucoceles. Recurrent proptosis secondary to an ethmoidal mucocele is a rare event after bony orbital decompression surgery, with only two cases reported in the international literature. Management requires ophthalmologic diagnosis and collaboration between the ophthalmologist and otorhinolaryngologist.

  13. Spontaneous extracranial decompression of epidural hematoma.

    PubMed

    Neely, John C; Jones, Blaise V; Crone, Kerry R

    2008-03-01

    Epidural hematoma (EDH) is a common sequela of head trauma in children. An increasing number are managed nonsurgically, with close clinical and imaging observation. We report the case of a traumatic EDH that spontaneously decompressed into the subgaleal space, demonstrated on serial CT scans that showed resolution of the EDH and concurrent enlargement of the subgaleal hematoma.

  14. Rapid decompression in the EA-6B.

    PubMed

    Hudson, S J; Todd, J S

    1998-08-01

    A Grumman EA-6B aircraft experienced a rapid pressurization failure at 27,000 feet. All four crew members had removed their oxygen masks and were breathing cabin air pressurized to 8,000 feet before the incident. Although none of the crew members developed signs or symptoms of decompression sickness, the potential for adversity was realized by all. Altitude decompression sickness (DCS) and pulmonary overinflation syndrome (POIS) represent potentially fatal complications of rapid decompression or uncontrolled ascent in aircraft. The signs and symptoms of DCS range from mild joint pain to eventual cardiopulmonary collapse and death. The symptoms of POIS are usually more abrupt and lethal. The medical management of DCS and POIS includes (1) maintenance of airway and cardiopulmonary resuscitation if necessary: (2) administration of 100% oxygen; (3) descent as per Naval Aviation Training and Operating Procedures Standardization guidelines; (4) horizontal body position; (5) maintenance of fluid intake; and (6) early medical evaluation by a flight surgeon or other physician qualified in the management of DCS. Symptoms of DCS may appear up to 24 hours after decompression, and continued monitoring or grounding of exposed individuals during this time is essential. Many controllable factors may predispose to DCS/POIS, and preventive measures should be taken to ensure maximum reduction of risk.

  15. Evaluation and management of decompression illness--an intensivist's perspective.

    PubMed

    Tetzlaff, Kay; Shank, Erik S; Muth, Claus M

    2003-12-01

    Decompression illness (DCI) is becoming more prevalent as more people engage in activities involving extreme pressure environments such as recreational scuba-diving. Rapid diagnosis and treatment offer these patients the best chance of survival with minimal sequelae. It is thus important that critical care physicians are able to evaluate and diagnose the signs and symptoms of DCI. The cornerstones of current treatment include the administration of hyperbaric oxygen and adjunctive therapies such as hydration and medications. However, managing patients in a hyperbaric environment does present additional challenges with respect to the particular demands of critical care medicine in an altered pressure environment. This article reviews the underlying pathophysiology, clinical presentation and therapeutic options available to treat DCI, from the intensivist's perspective.

  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. [Analysis of decompression safety during extravehicular activity of astronauts in the light of probability theory].

    PubMed

    Nikolaev, V P; Katuntsev, V P

    1998-01-01

    Objectives of the study were comparative assessment of the risk of decompression sickness (DCS) in human subjects during shirt-sleeve simulation of extravehicular activity (EVA) following Russian and U.S. protocols, and analysis of causes of the difference between real and simulated EVA decompression safety. To this end, DCS risk during exposure to a sing-step decompression was estimated with an original method. According to the method, DCS incidence is determined by distribution of nucleation efficacy index (z) in the worst body tissues and its critical values (zm) as a function of initial nitrogen tension in these tissues and final ambient pressure post decompression. Gaussian distribution of z values was calculated basing on results of the DCS risk evaluation on the U.S. EVA protocol in an unsuited chamber test with various pre-breath procedures (Conkin et al., 1987). Half-time of nitrogen washout from the worst tissues was presumed to be 480 min. Calculated DCS risk during short-sleeve EVA simulation by the Russian and U.S. protocols with identical physical loading made up 19.2% and 23.4%, respectively. Effects of the working spacesuit pressure, spacesuit rigidity, metabolic rates during operations in EVA space suit, transcutaneous nitrogen exchange in the oxygen atmosphere of space suit, microgravity, analgesics, short compression due to spacesuit leak tests on the eye of EVA are discussed. Data of the study illustrate and advocate for high decompression safety of current Russian and U.S. EVA protocols.

  19. 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

  20. 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

  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. 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

  3. Inadequate Surgical Decompression in Patients with Cervical Myelopathy: A Retrospective Review

    PubMed Central

    Bhalla, Amandeep; Rolfe, Kevin W.

    2015-01-01

    Study Design  Retrospective study. Objective  We reviewed cases of surgically treated cervical spondylotic myelopathy (CSM) or chronic, degenerative myelopathy of the subaxial cervical spine to study the incidence of inadequate surgical decompression. Methods  We included all persons treated at our institution after a first surgical decompression for CSM over a 3-year period. Inadequate original surgical decompression was defined as neurologic decline within 12 months postoperatively and ongoing impingement of the spinal cord with <1-mm change in anteroposterior canal dimension from pre- to postoperative magnetic resonance imaging (MRI) leading to revision decompressive surgery. Revisions for other reasons were not counted as inadequate. Results  Of 50 patients, 5 (10%) required revision decompression for neurologic decline and inadequate change in space available for the cord on postoperative imaging; 4 patients declined within the first 6 months and 1 patient at 8 months postoperatively. None of the 5 declined further after posterior revision, but none recovered from the interval loss. All 5 had undergone anterior approaches, for an anterior inadequacy rate of 23% (5 of 22). None of the 28 patients having posterior or combined approach declined at 2 years or had <1-mm change on postoperative MRI. The difference between anterior and posterior approaches was statistically significant (p = 0.018). Conclusions  The rate of inadequate surgical decompression for CSM was greater than expected in this series and directly associated with an anterior approach. No cases of inadequacy occurred for posterior or combined approaches. Postoperative neuroradiographic imaging such as MRI should be entertained routinely for this entity or at least for anterior-only approaches. PMID:27555995

  4. 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

    2015-12-03

    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.

  5. Decompression from a deep nitrogen/oxygen saturation dive--a case report.

    PubMed

    Barry, P D; Vann, R D; Youngblood, D A; Peterson, R E; Bennett, P B

    1984-12-01

    Ten divers participated in a 4.5 d nitrogen/oxygen saturation dive to 165 fsw. There were daily 2 h excursions to 61 msw (200 fsw). The divers breathed air during the excursions and 0.51 bar (0.5 atm) oxygen in nitrogen at 50.3 msw (165 fsw). The final decompression began 6 h after the last excursion. The oxygen partial pressure was 0.51 bar (0.5 atm) from 50.3 to 13.7 msw (165 to 45 fsw), and air was used from 13.7 msw (45 fsw) to the surface. By 6.1 msw (20 fsw), four divers had developed decompression sickness. A fifth diver developed decompression sickness during a commercial air flight 68 h after surfacing. Comparison of ascent rates for this dive and for air or nitrogen/oxygen saturation dives reported in the literature suggests that deeper dives require slower rates of ascent. Dives shallower than 30.5 msw (100 fsw) had a mean ascent rate of 1 msw/h (3.2 fsw/h) and 14 decompression incidents in 107 man-exposures. Dives deeper than 30.5 msw (100 fsw) had a mean rate of 0.76 msw/h (2.5 fsw/h) and 14 incidents in 45 man-exposures.

  6. 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

  7. 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.

  8. Extremely slow rate of evolution in the HOX cluster revealed by comparison between Tanzanian and Indonesian coelacanths.

    PubMed

    Higasa, Koichiro; Nikaido, Masato; Saito, Taro L; Yoshimura, Jun; Suzuki, Yutaka; Suzuki, Hikoyu; Nishihara, Hidenori; Aibara, Mitsuto; Ngatunga, Benjamin P; Kalombo, Hassan W J; Sugano, Sumio; Morishita, Shinichi; Okada, Norihiro

    2012-09-01

    Coelacanths are known as "living fossils" because their morphology has changed very little from that in the fossil record. To elucidate why coelacanths have evolved so slowly is thus of primary importance in evolutionary biology. In the present study, we determined the entire sequence of the HOX cluster of the Tanzanian coelacanth (Latimeria chalumnae) and compared it with that of the Indonesian coelacanth (L. menadoensis), which was available in the literature. The most intriguing result was the extremely small genetic divergence between the two coelacanths. The synonymous divergence of the HOX coding region between the two coelacanths was estimated to be 0.07%, which is ~11-fold smaller than that of human-chimp. When we applied the estimated divergence time of the two coelacanths of 6 million years ago (MYA) and 30 MYA, which were proposed in independent mitochondrial DNA analyses, the synonymous substitution rate of the coelacanth HOX cluster was estimated to be ~11-fold and 56-fold smaller than that of human-chimp, respectively. Thus, the present study implies that the reduction of the nucleotide substitution rate in coelacanth HOX genes may account for the conservation of coelacanth morphology during evolution.

  9. Treatment of hemimasticatory spasm with microvascular decompression.

    PubMed

    Wang, Yong-Nan; Dou, Ning-Ning; Zhou, Qiu-Meng; Jiao, Wei; Zhu, Jin; Zhong, Jun; Li, Shi-Ting

    2013-01-01

    Hemimasticatory spasm is a rare disorder characterized by paroxysmal involuntary contraction of the jaw-closing muscles. As the ideology and pathogenesis of the disease are still unclear, there has been no treatment that could give rise to a good outcome so far. Herein, we tried to use surgical management to cure the disease. Six patients with the disease were included in this study. These patients underwent microvascular decompression of the motor fibers of the trigeminal root. After the operation, all faces of the patients felt relaxed at varied degrees, except for 1 patient. Our study showed that microvascular decompression of the trigeminal nerve could lead to a better outcome. However, a control study with a large sample is needed before this technique is widely used.

  10. 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.

  11. Percutaneous endoscopic decompression for lumbar spinal stenosis.

    PubMed

    Ahn, Yong

    2014-11-01

    Percutaneous endoscopic lumbar discectomy has become a representative minimally invasive spine surgery for lumbar disc herniation. Due to the remarkable evolution in the techniques available, the paradigm of spinal endoscopy is shifting from treatments of soft disc herniation to those of lumbar spinal stenosis. Lumbar spinal stenosis can be classified into three categories according to pathological zone as follows: central stenosis, lateral recess stenosis and foraminal stenosis. Moreover, percutaneous endoscopic decompression (PED) techniques may vary according to the type of lumbar stenosis, including interlaminar PED, transforaminal PED and endoscopic lumbar foraminotomy. However, these techniques are continuously evolving. In the near future, PED for lumbar stenosis may be an efficient alternative to conventional open lumbar decompression surgery.

  12. 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

  13. 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.

  14. Cortical blindness following posterior lumbar decompression and fusion.

    PubMed

    Agarwal, Nitin; Hansberry, David R; Goldstein, Ira M

    2014-01-01

    Perioperative vision loss following non-ocular surgery is a well-documented phenomenon. In particular, perioperative vision loss has been frequently cited following spinal surgery. Although the rate of vision compromise in spinal surgery is relatively low, the consequences can be quite severe and devastating for the patient. We report a 60-year-old woman who initially presented with back and left leg pain as well as paraparesis. Imaging studies of the lumbar spine showed bony erosion consistent with tumor infiltration of the L3 and L4 spinal segments. Laminectomy at the L2-L4 levels for decompression of the intraspinal tumor was performed. Pathology of the resected bone was consistent with metastatic adenocarincoma. Postoperatively, the patient suffered severe anemia and bilateral infarctions of the posterior cerebral arteries and occipital lobes resulting in vision compromise. Although a definitive pathogenesis remains unknown, preoperative cardiovascular issues and intraoperative hemodynamic instabilities have typically been implicated as high risk factors. High risk factors for this novel clinical presentation of visual compromise following posterior lumbar laminectomy with decompression for an intraspinal tumor are reported. PMID:23791834

  15. [Surgical decompression for massive cerebellar infarction].

    PubMed

    Ogasawara, K; Koshu, K; Nagamine, Y; Fujiwara, S; Mizoi, K; Yoshimoto, T

    1995-01-01

    The authors report 10 patients with progressive neurological deterioration due to massive cerebellar infarctions. Computerized tomography scans confirmed obstructive hydrocephalus and brain stem compression. All 10 patients (seven men, three women; mean age, 59 years) were treated by external ventricular drainage and decompressive suboccipital craniectomy. After discharge from the hospital, they were followed up (23-101 months) and their functional independence was evaluated by the Barthel Index. The condition of three patients with brain-stem infarction had deteriorated despite decompressive surgery. Two of these died during the acute stage and one because severely disabled. The remaining seven patients showed neurological improvement during the postoperative period. Four patients with preoperative Japan Coma Scale of 100 returned to their previous jobs within the follow-up period and three patients with preoperative Japan Coma Scale of 200 required some assistance in daily activities. It is suggested that decompressive surgery may be beneficial for massive cerebellar infarction. The postoperative prognosis depends mainly on the presence or absence of coexisting brain-stem infarction. It is possible that, without brain-stem infarction, patients who remained in a "dependent" state may have recovered better if they had been operated on earlier.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. Decompression versus decompression and fusion for degenerative lumbar stenosis: analysis of the factors influencing the outcome of back pain and disability

    PubMed Central

    Tarantino, Roberto; Nigro, Lorenzo; Rullo, Marika; Messina, Domenico; Diacinti, Daniele; Delfini, Roberto

    2016-01-01

    Background The objective of this study is to evaluate the factors influencing the outcome of back pain and disability in patients operated for lumbar stenosis without instability and deformity using two classical surgical techniques: decompression alone and decompression plus fusion. Methods This is a retrospective cohort study of patients who underwent lumbar surgery with standard posterior decompression or standard posterior decompression plus pedicle screw fixation for degenerative lumbar stenosis without deformity, spondylolisthesis or instability at our department from June 2010 to January 2014. They were divided into two groups: decompression group (D) and decompression-fusion group (F). We analyzed the following factors: age, gender, levels of stenosis, pre-surgical “micro-instability”, and post-surgical “micro-instability”. Results A total of 174 patients were enrolled in the study. Both Graphic Rating Scale (GRS) and Oswestry Disability Index (ODI) scores were significantly decreased after surgery (P<0.001). Female patients appeared to have lesser improvements from surgery, for both D and F groups. An analysis of variance using the decrease of pain (GRS pre-post) as dependent variable and type of surgery, age, gender and their interaction as factors showed that the main effects of type of surgery and gender were significant. The analysis of variance for the decrease of pain (GRS) and disability (ODI) according to the levels of stenosis showed a significant interaction for GRS scores. Female patients that underwent fixation surgery reported the least improvement in disability. A significant interaction was found on the one-way analysis of variance for the D group without pre-surgical micro-instability using post-surgical micro-instability as factor. Conclusions Our study supports posterior decompression alone as the gold standard option as treatment for lumbar stenosis without instability and deformity. Additional fusion should be considered only to

  1. Decompression versus decompression and fusion for degenerative lumbar stenosis: analysis of the factors influencing the outcome of back pain and disability

    PubMed Central

    Tarantino, Roberto; Nigro, Lorenzo; Rullo, Marika; Messina, Domenico; Diacinti, Daniele; Delfini, Roberto

    2016-01-01

    Background The objective of this study is to evaluate the factors influencing the outcome of back pain and disability in patients operated for lumbar stenosis without instability and deformity using two classical surgical techniques: decompression alone and decompression plus fusion. Methods This is a retrospective cohort study of patients who underwent lumbar surgery with standard posterior decompression or standard posterior decompression plus pedicle screw fixation for degenerative lumbar stenosis without deformity, spondylolisthesis or instability at our department from June 2010 to January 2014. They were divided into two groups: decompression group (D) and decompression-fusion group (F). We analyzed the following factors: age, gender, levels of stenosis, pre-surgical “micro-instability”, and post-surgical “micro-instability”. Results A total of 174 patients were enrolled in the study. Both Graphic Rating Scale (GRS) and Oswestry Disability Index (ODI) scores were significantly decreased after surgery (P<0.001). Female patients appeared to have lesser improvements from surgery, for both D and F groups. An analysis of variance using the decrease of pain (GRS pre-post) as dependent variable and type of surgery, age, gender and their interaction as factors showed that the main effects of type of surgery and gender were significant. The analysis of variance for the decrease of pain (GRS) and disability (ODI) according to the levels of stenosis showed a significant interaction for GRS scores. Female patients that underwent fixation surgery reported the least improvement in disability. A significant interaction was found on the one-way analysis of variance for the D group without pre-surgical micro-instability using post-surgical micro-instability as factor. Conclusions Our study supports posterior decompression alone as the gold standard option as treatment for lumbar stenosis without instability and deformity. Additional fusion should be considered only to

  2. Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension.

    PubMed

    Hutchinson, Peter J; Kolias, Angelos G; Timofeev, Ivan S; Corteen, Elizabeth A; Czosnyka, Marek; Timothy, Jake; Anderson, Ian; Bulters, Diederik O; Belli, Antonio; Eynon, C Andrew; Wadley, John; Mendelow, A David; Mitchell, Patrick M; Wilson, Mark H; Critchley, Giles; Sahuquillo, Juan; Unterberg, Andreas; Servadei, Franco; Teasdale, Graham M; Pickard, John D; Menon, David K; Murray, Gordon D; Kirkpatrick, Peter J

    2016-09-22

    Background The effect of decompressive craniectomy on clinical outcomes in patients with refractory traumatic intracranial hypertension remains unclear. Methods From 2004 through 2014, we randomly assigned 408 patients, 10 to 65 years of age, with traumatic brain injury and refractory elevated intracranial pressure (>25 mm Hg) to undergo decompressive craniectomy or receive ongoing medical care. The primary outcome was the rating on the Extended Glasgow Outcome Scale (GOS-E) (an 8-point scale, ranging from death to "upper good recovery" [no injury-related problems]) at 6 months. The primary-outcome measure was analyzed with an ordinal method based on the proportional-odds model. If the model was rejected, that would indicate a significant difference in the GOS-E distribution, and results would be reported descriptively. Results The GOS-E distribution differed between the two groups (P<0.001). The proportional-odds assumption was rejected, and therefore results are reported descriptively. At 6 months, the GOS-E distributions were as follows: death, 26.9% among 201 patients in the surgical group versus 48.9% among 188 patients in the medical group; vegetative state, 8.5% versus 2.1%; lower severe disability (dependent on others for care), 21.9% versus 14.4%; upper severe disability (independent at home), 15.4% versus 8.0%; moderate disability, 23.4% versus 19.7%; and good recovery, 4.0% versus 6.9%. At 12 months, the GOS-E distributions were as follows: death, 30.4% among 194 surgical patients versus 52.0% among 179 medical patients; vegetative state, 6.2% versus 1.7%; lower severe disability, 18.0% versus 14.0%; upper severe disability, 13.4% versus 3.9%; moderate disability, 22.2% versus 20.1%; and good recovery, 9.8% versus 8.4%. Surgical patients had fewer hours than medical patients with intracranial pressure above 25 mm Hg after randomization (median, 5.0 vs. 17.0 hours; P<0.001) but had a higher rate of adverse events (16.3% vs. 9.2%, P=0.03). Conclusions At 6

  3. Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension.

    PubMed

    Hutchinson, Peter J; Kolias, Angelos G; Timofeev, Ivan S; Corteen, Elizabeth A; Czosnyka, Marek; Timothy, Jake; Anderson, Ian; Bulters, Diederik O; Belli, Antonio; Eynon, C Andrew; Wadley, John; Mendelow, A David; Mitchell, Patrick M; Wilson, Mark H; Critchley, Giles; Sahuquillo, Juan; Unterberg, Andreas; Servadei, Franco; Teasdale, Graham M; Pickard, John D; Menon, David K; Murray, Gordon D; Kirkpatrick, Peter J

    2016-09-22

    Background The effect of decompressive craniectomy on clinical outcomes in patients with refractory traumatic intracranial hypertension remains unclear. Methods From 2004 through 2014, we randomly assigned 408 patients, 10 to 65 years of age, with traumatic brain injury and refractory elevated intracranial pressure (>25 mm Hg) to undergo decompressive craniectomy or receive ongoing medical care. The primary outcome was the rating on the Extended Glasgow Outcome Scale (GOS-E) (an 8-point scale, ranging from death to "upper good recovery" [no injury-related problems]) at 6 months. The primary-outcome measure was analyzed with an ordinal method based on the proportional-odds model. If the model was rejected, that would indicate a significant difference in the GOS-E distribution, and results would be reported descriptively. Results The GOS-E distribution differed between the two groups (P<0.001). The proportional-odds assumption was rejected, and therefore results are reported descriptively. At 6 months, the GOS-E distributions were as follows: death, 26.9% among 201 patients in the surgical group versus 48.9% among 188 patients in the medical group; vegetative state, 8.5% versus 2.1%; lower severe disability (dependent on others for care), 21.9% versus 14.4%; upper severe disability (independent at home), 15.4% versus 8.0%; moderate disability, 23.4% versus 19.7%; and good recovery, 4.0% versus 6.9%. At 12 months, the GOS-E distributions were as follows: death, 30.4% among 194 surgical patients versus 52.0% among 179 medical patients; vegetative state, 6.2% versus 1.7%; lower severe disability, 18.0% versus 14.0%; upper severe disability, 13.4% versus 3.9%; moderate disability, 22.2% versus 20.1%; and good recovery, 9.8% versus 8.4%. Surgical patients had fewer hours than medical patients with intracranial pressure above 25 mm Hg after randomization (median, 5.0 vs. 17.0 hours; P<0.001) but had a higher rate of adverse events (16.3% vs. 9.2%, P=0.03). Conclusions At 6

  4. 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.

  5. 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.

  6. [Reappraise the value of orbital decompression for thyroid associated ophthalmopathy].

    PubMed

    Xiao, Li-hua

    2012-08-01

    Compressive optic neuropathy and exposure keratopathy is classical indications of orbital decompression surgery for thyroid associated ophthalmopathy. Recently, its therapeutic value should extend to cosmetic requirement, the entity of congestive orbitopathy, ocular hypertension and hormonal resistance. In order to improve the safe and efficacy of orbital decompressions, we need the graded decompression plans and the modified areas of bone removal. The preferred area of bone removal is deep lateral wall. In serious patients, a combined medial, inferior and deep lateral wall decompression is recommended. There have also been technical advances in the cosmetic incisions such as transconjunctival, eyelid crease or endoscopic access. Removing periorbital fat is a supplement skill for bony decompression. The removed amount and indications should be regulated strictly. Individual operative project is the tendency of development of orbital decompressions.

  7. Clinical outcomes of microendoscopic decompression surgery for cervical myelopathy

    PubMed Central

    Yoshida, Munehito; Yamada, Hiroshi; Nakagawa, Yukihiro; Maio, Kazuhiro; Kawai, Masaki; Iwasaki, Hiroshi

    2009-01-01

    Retrospective study on the results of microendoscopic decompression surgery for the treatment of cervical myelopathy. The purpose of this study was to describe the microendoscopic laminoplasty (MEL) technique as the surgical method in the treatment of cervical myelopathy, and to document the clinical outcomes for MEL surgery. Endoscopic surgery poses several challenges for the aspiring endoscopic surgeons, the most critical of which is mastering hand–eye coordination. With training in live animal and cadaver surgery, the technical progress has reduced the problem of morbidity following surgery. The authors have performed microendoscopic decompression surgery on more than 2,000 patients for lumbar spinal canal stenosis. Fifty-one patients underwent the posterior decompression surgery using microendoscopy for cervical myelopathy at authors’ institute. The average age was 62.9 years. The criteria for exclusion were cervical myelopathy with tumor, trauma, severe ossification of posterior longitudinal ligament, rheumatoid arthritis, pyogenic spondylitises, destructive spondylo-arthropathies, and other combined spinal lesions. The items evaluated were neurological evaluation, recovery rates; these were calculated following examination using the Hirabayashi’s method with the criteria proposed by the Japanese Orthopaedic Association scoring system (JOA score). The mean follow-up period was 20.3 months. The average of JOA score was 10.1 points at the initial examination and 13.6 points at the final follow-up. The average recovery rate was 52.5%. The recovery rate according to surgical levels was, respectively, 56.5% in one level, 46.3% in two levels and 54.1% in more than three levels. The complications were as follows: one patient sustained a pin-hole-like dura mater injury inflicted by a high-speed air-drill during surgery, one patient developed an epidural hematoma 3 days after surgery, and two patients had the C5 nerve root palsy after surgery. The epidural

  8. [Neurologic accident of decompression: a new indication of transesophageal echocardiography].

    PubMed

    Boussuges, A; Blanc, P; Habib, G

    1995-05-20

    Decompression sickness in a 33-year-old SCUBA diver led to neurological lesions with brain damage. The existence of a patent foramen ovale detected with a transoesophageal contrast echocardiography suggested paradoxal gas embolism. This observation emphasizes the intest of transoesophageal contrast echocardiography in decompression sickness as discussed in the literature. Its widely utilization would permit a better understanding of the pathophysiology of decompression sickness. It also may help the physician in deciding whether or not to authorize further diving.

  9. 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

  10. Arthroscopic Scapulothoracic Decompression for Snapping Scapula Syndrome

    PubMed Central

    Saper, Michael; Kasik, Connor; Dietzel, Douglas

    2015-01-01

    Snapping scapula syndrome at the superomedial corner of the scapula can lead to significant shoulder dysfunction. Bursectomy with or without partial scapulectomy is currently the most beneficial primary method of treatment in patients in whom nonoperative therapy fails. Arthroscopic access to the scapulothoracic space is simple and reproducible with the technique described in this report. The bursal tissue can be cleared, optimizing visualization of the scapulothoracic space and the anatomic structures. Arthroscopic decompression of the scapulothoracic bursa and resection of the superomedial corner of the scapula are highlighted in a video example. PMID:26870637

  11. Arthroscopic Scapulothoracic Decompression for Snapping Scapula Syndrome.

    PubMed

    Saper, Michael; Kasik, Connor; Dietzel, Douglas

    2015-12-01

    Snapping scapula syndrome at the superomedial corner of the scapula can lead to significant shoulder dysfunction. Bursectomy with or without partial scapulectomy is currently the most beneficial primary method of treatment in patients in whom nonoperative therapy fails. Arthroscopic access to the scapulothoracic space is simple and reproducible with the technique described in this report. The bursal tissue can be cleared, optimizing visualization of the scapulothoracic space and the anatomic structures. Arthroscopic decompression of the scapulothoracic bursa and resection of the superomedial corner of the scapula are highlighted in a video example. PMID:26870637

  12. 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

  13. 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.

  14. Cross-adaptive effects of cold, hypoxia, or physical training on decompression sickness in mice.

    PubMed

    Rattner, B A; Gruenau, S P; Altland, P D

    1979-08-01

    The effects of adaptation to cold, hypoxia, or exercise on hyperbaric decompression tolerance were investigated in two factorial experiments. For either 14 or 28 days, groups of mice were handled (control); exposed discontinuously for 4 h to cold (4 degrees C) or hypoxia (P approximately 379 or 320 Torr); or exercised by swimming (15 min at 31 degrees C) or treadmill excursion (8.1 m/min for 1 or 1.5 h). The animals were divided into subgroups, exposed to one of three hydrostatic pressures (7.6--11.1 ATA) for 30 min, decompressed, and observed to determine survival rate or bends incidence (type II decompression sickness). Decompression sickness was significantly reduced (P less than 0.05) in the treadmill-trained animals, was unchanged in cold-exposed and swim-exercised mice, and tended to increase in animals adapted to hypoxia. Enhanced tolerance by treadmill training is presumably due to lean body conformation, which could reduce nitrogen saturation of tissues, and greater muscle capillarization and cardiovascular fitness, which may improve nitrogen elimination. Reduced tolerance with adaptation to hypoxia may be attributed to rheological changes associated with polycythemia, which facilitate bubble production.

  15. Optic Nerve Decompression through a Supraorbital Approach

    PubMed Central

    Rigante, Luigi; Evins, Alexander I.; Berra, Luigi V.; Beer-Furlan, André; Stieg, Philip E.; Bernardo, Antonio

    2015-01-01

    Objective We propose a stepwise decompression of the optic nerve (ON) through a supraorbital minicraniotomy and describe the surgical anatomy of the ON as seen through this approach. We also discuss the clinical applications of this approach. Methods Supraorbital approaches were performed on 10 preserved cadaveric heads (20 sides). First, 3.5-cm skin incisions were made along the supraciliary arch from the medial third of the orbit and extended laterally. A 2 × 3-cm bone flap was fashioned and extradural dissections were completed. A 180-degree unroofing of the ON was achieved, and the length and width of the proximal and distal portions of the optic canal (OC) were measured. Results The supraorbital minicraniotomy allowed for identification of the anterior clinoid process and other surgical landmarks and adequate drilling of the roof of the OC with a comfortable working angle. A 25-degree contralateral head rotation facilitated visualization of the ON. Conclusion The supraorbital approach is a minimally invasive and cosmetically favorable alternative to more extended approaches with longer operative times used for the management of ON decompression in posttraumatic or compressive optic neuropathy from skull base pathologies extending into the OC. The relative ease of this approach provides a relatively short learning curve for developing neurosurgeons. PMID:26225308

  16. 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

  17. 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.

  18. Multimodal evaluation of CSF dynamics following extradural decompression for Chiari malformation Type I.

    PubMed

    Quon, Jennifer L; Grant, Ryan A; DiLuna, Michael L

    2015-06-01

    OBJECT Extradural decompression is a minimally invasive technique for treating Chiari malformation Type I (CM-I) that avoids the complications of dural opening. While there is no agreement on which surgical method is optimal, mounting evidence demonstrates that extradural decompression effectively treats clinical symptoms, with a minimal reoperation rate. Neurological symptoms such as headache may be related to obstructed flow of CSF, and one aspect of successful extradural decompression is improved CSF dynamics. In this series, the authors report on their use of phase-contrast cine flow MRI to assess CSF flow as well as satisfactory decompression. METHODS The authors describe their first surgical series of 18 patients with CM-I undergoing extradural decompression and correlate clinical improvement with radiological changes. Patients were categorized as having complete, partial, or no resolution of their symptoms. Posterior fossa area, cisterna magna area, and tonsillar herniation were assessed on T2-weighted MRI, whereas improvement of CSF flow was evaluated with phase-contrast cine flow MRI. All patients received standard pre- and postoperative MRI studies; 8 (44.4%) patients had pre- and postoperative phase-contrast cine, while the rest underwent cine studies only postoperatively. RESULTS All 18 patients presented with symptomatic CM-I, with imaging studies demonstrating tonsillar herniation ≥ 5 mm, and 2 patients had associated syringomelia. All patients underwent suboccipital decompression and C-1 laminectomy with splitting of the dura. Patients with complete resolution of their symptoms had a greater relative increase in cisterna magna area compared with those with only partial improvement (p = 0.022). In addition, in those with complete improvement the preoperative cisterna magna area was smaller than in those who had either partial (0.020) or no (0.025) improvement. Ten (91%) of the 11 patients with improved flow also had improvement in their symptoms

  19. [Results of decompressive-stabilizing procedures via unilateral approach in lumbar spinal stenosis].

    PubMed

    Krut'ko, A V

    2012-01-01

    Aim of this study was to investigate the capabilities, advantages and limitations of bilateral decompression via unilateral approach in decompressive-stabilizing procedures in patients with degenerative lumbar spine disease, and to develop the technology and its technical performance. The controlled study included 372 patients (age range was 27-74 years). All of them were operated due to clinical manifestation of lumbar spinal stenosis. The main group consisted of 44 patients who underwent bilateral decompression via unilateral approach with stabilization of involved segments. The control group included 328 patients who were operated using standard bilateral technique with stabilization. A total of 52 segments were treated in the first group and 351 in the second one. In all patients with neurogenic intermittent claudication symptoms relieved after decompressive-stabilizing surgery. Analysis of duration of surgery (considering 1 segment) demonstrated that less invasive technique requires as much time as conventional. However mean intraoperative blood loss in the first group was twice as low as the second. Neither patient from the first group required hemotransfusion while in the second group in 57 (17.4%) cases hemotransfusion was performed due to blood loss. In the early postoperative period in both groups intensity of pain (according to VAS) gradually decreased. Mean hospital stay was 9.9 +/- 3.1 day in the main group and 14.7 +/- 4.7 days in the control group. Bilateral spinal canal decompression via unilateral approach decreases surgical trauma, blood loss, complication rate and hospital stay. Postoperative results are comparable with conventional technique.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  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. 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.

  7. Decompression sickness ('the bends') in sea turtles.

    PubMed

    García-Párraga, D; Crespo-Picazo, J L; de Quirós, Y Bernaldo; Cervera, V; Martí-Bonmati, L; Díaz-Delgado, J; Arbelo, M; Moore, M J; Jepson, P D; Fernández, Antonio

    2014-10-16

    Decompression sickness (DCS), as clinically diagnosed by reversal of symptoms with recompression, has never been reported in aquatic breath-hold diving vertebrates despite the occurrence of tissue gas tensions sufficient for bubble formation and injury in terrestrial animals. Similarly to diving mammals, sea turtles manage gas exchange and decompression through anatomical, physiological, and behavioral adaptations. In the former group, DCS-like lesions have been observed on necropsies following behavioral disturbance such as high-powered acoustic sources (e.g. active sonar) and in bycaught animals. In sea turtles, in spite of abundant literature on diving physiology and bycatch interference, this is the first report of DCS-like symptoms and lesions. We diagnosed a clinico-pathological condition consistent with DCS in 29 gas-embolized loggerhead sea turtles Caretta caretta from a sample of 67. Fifty-nine were recovered alive and 8 had recently died following bycatch in trawls and gillnets of local fisheries from the east coast of Spain. Gas embolization and distribution in vital organs were evaluated through conventional radiography, computed tomography, and ultrasound. Additionally, positive response following repressurization was clinically observed in 2 live affected turtles. Gas embolism was also observed postmortem in carcasses and tissues as described in cetaceans and human divers. Compositional gas analysis of intravascular bubbles was consistent with DCS. Definitive diagnosis of DCS in sea turtles opens a new era for research in sea turtle diving physiology, conservation, and bycatch impact mitigation, as well as for comparative studies in other air-breathing marine vertebrates and human divers.

  8. [Evaluation of heart impact in the 100 m extreme intensity sport using near-infrared non-invasive muscle oxygen detecting device and sports heart rate detection technology].

    PubMed

    Wang, Pei-Yong; Long, Fei-Xiao; Fu, Lan-Ying; Li, Yue; Ding, Hai-Shu; Qu, An-Lian; Zhou, Xiao-Ping

    2010-02-01

    Using continuous two wavelength near-infrared technology to detect the variation in the consistency of oxygen hemoglobin in the muscle and the sports heart rate wireless real time collection technology, we devised the real time muscle tissue oxygenation and instantaneous heart rate experiment scheme and implemented it for the process of the 100 m run with two parameters given simultaneously. The experiment shows that the concentration of the oxygen hemoglobin in the muscle tissue continues decreasing after the end of the 100 m run, and the time interval between the moment when the concentration of the oxygen hemoglobin attains the minimum value and the moment when the athletes finish the 100 m run is (6.65 +/- 1.10) sec; while the heart rate continues increasing after the end of the 100 m run, and the time interval between the moment when the heart rate attains the maximum value and the moment when the athletes finish the 100 m run is (8.00 +/- 1.57) sec. The results show that the two wavelength near-infrared tissue oxygenation detection technology and the sports heart rate real time collection equipment can accurately measure the sports tissue oxygenation and the heart rate in the extreme intensity sport, and reveal the process of muscle oxygen transportation and consumption and its dynamic character with the heart rate in the extreme intensity sport.

  9. 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

  10. Decompressive hemicraniectomy for treatment of space occupying ischemic stroke after repair of type-A aortic dissection.

    PubMed

    Biancari, Fausto; Lahtinen, Maija; Erkinaro, Tiina; Liisanantti, Janne; Anttila, Vesa; D'Andrea, Vito

    2015-01-01

    Postoperative stroke after cardiac surgery is often a lethal complication. Herein, we report on a patient who suffered space-occupying ischemic stroke after surgical treatment of type A aortic dissection. He underwent decompressive hemicraniectomy and, despite residual hemianopsia and left side flaccid hemiplegia, survived surgery and was discharged for rehabilitation. This observation suggests that early consultation with a neurosurgeon, intracranial pressure monitoring and, when indicated, decompressive hemicraniectomy should be considered in order to reduce the high mortality rate associated with ischemic stroke after cardiac surgery.

  11. 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

  12. 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

  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. Gene-environment mismatch in decompression sickness and air embolism.

    PubMed

    Alcock, Joe; Brainard, Andrew H

    2010-08-01

    Decompression sickness causes injury and death in SCUBA divers when air bubbles obstruct the flow of blood. Platelets aggregate in response to gas and promote inflammation. Inflammation in decompression sickness may have its origin in the innate immune system's response to pathogens. Bubbles are often found in tissues during gas-forming infections and in infection-prone states. In these diseases, intravascular gas offers a signal of infection to immune cells. Platelet activation by gas may often accompany a beneficial immune response to pathogens. Pathologic bubble-platelet interaction in decompression illness may be an example of gene-environment mismatch.

  15. Incidence of decompression illness in amateur scuba divers.

    PubMed

    Wilmshurst, P; Allen, C; Parish, T

    This paper reports changes in the incidence and manifestations of decompression illness in amateur scuba divers in the United Kingdom (UK) between 1981 and 1993, a period during which the popularity of the sport increased. Since 1981, there has been a trend to increased annual incidence of decompression illness, but the large yearly fluctuations reflect a considerable annual variation in the numbers of dives. The need for recompression facilities to treat decompression illness in amateur scuba divers in the UK should take account of this greater public participation in the sport, and should also allow for large annual fluctuations related to meteorological and financial factors.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. Extreme strain rate and temperature dependence of the mechanical properties of nano silicon nitride thin layers in a basal plane under tension: a molecular dynamics study.

    PubMed

    Lu, Xuefeng; Wang, Hongjie; Wei, Yin; Wen, Jiangbo; Niu, Min; Jia, Shuhai

    2014-08-01

    Molecular dynamics simulations are performed to clarify the extreme strain rate and temperature dependence of the mechanical behaviors of nano silicon nitride thin layers in a basal plane under tension. It is found that fracture stresses show almost no change with increasing strain rate. However, fracture strains decrease gradually due to the appearance of additional N(2c)-Si bond breaking defects in the deformation process. With increasing loading temperature, there is a noticeable drop in fracture stress and fracture strain. In the low temperature range, roughness phases can be observed owing to a combination of factors such as configuration evolution and energy change.

  3. 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

  4. 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.

  5. Decompression sickness and arterial gas embolism in sports scuba divers.

    PubMed

    Gorman, D F

    1989-07-01

    Diving underwater with breathing apparatus is an increasingly popular sport. Consequently, the number of diving-related accidents, including both decompression sickness and arterial gas embolism, have increased. Though both involve bubbles, decompression sickness is a disease which involves gas bubbles forming in tissues and venous blood, while arterial gas embolism results from the introduction of gas bubbles directly into the arterial circulation. Although the pathologies and natural histories of decompression sickness and arterial gas embolism are different, the treatment of these conditions is essentially the same. Compression in a recompression chamber is the definitive treatment of both decompression sickness and arterial gas embolism, and any delay before treatment must be minimised if a good outcome is desired.

  6. Bubble growth and mechanical properties of tissue in decompression.

    PubMed

    Vann, R D; Clark, H G

    1975-09-01

    A survey of decompression literature leads to the conclusion that when tissue is subjected to gaseous supersaturation, pre-existing gas micronuclei grow into the gas bubbles which are routinely observed in decompression studies. These micronuclei may originate from mechanically induced tribonucleation or cavitation within joints. A new tissue model for decompression sickness based upon failure theory in rubber is proposed. The model shows theoretically that pre-existing sea-level nuclei can be stabilized at depth by elastic forces in tissue. These same elastic forces restrain the growth of nuclei when supersaturation occurs. Mechanical stress will lower the gaseous supersaturation required for growth of nuclei. Gaseous supersaturation, mechanical stress, and the elastic properties of various tissues interact to produce unbounded bubble growth leading to tissue lesions when combined gaseous and mechanical supersaturation exceeds a threshold value. The recommendation is made that the high levels of supersaturation generally used for the decompression of men be reduced.

  7. Analysis of gas composition of intravascular bubbles produced by decompression.

    PubMed

    Ishiyama, A

    1983-06-01

    The gas composition of intravascular bubbles produced by decompression was investigated in rabbits using gas chromatography. The animals were exposed to 8 ATA for 30 min. All samples of bubbles were taken from the animals under 0.2 ATA pressure gradient so that no air could enter the sampling system from the outside. The percentage of carbon dioxide in the bubbles tended to decrease at first and then increased with post-decompression time. On the other hand, the percentage of oxygen tended to change in the opposite manner. Actual analysis of bubbles in the living decompressed animals indicates that carbon dioxide may be an outstanding factor in the initiation and early growth of bubbles. In view of this, Haldane's classical maximum supersaturation limit for avoiding decompression sickness should be examined and possibly modified for gases other than nitrogen.

  8. 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

  9. 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.

  10. 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

  11. Cases from the aerospace medicine residents' teaching file. Decompression sickness.

    PubMed

    Taylor, G N

    2000-12-01

    Decompression sickness is an uncommon but serious risk associated with flying and SCUBA diving with potential for significant morbidity and mortality. It can occur in both novice and experienced individuals. This case illustrates an atypical presentation of decompression sickness in an experienced amateur SCUBA diver. Clinical suspicion must be high, since the presenting symptoms can be nonspecific as in this case. Early recognition and treatment are important for maximum recovery.

  12. Heliox treatment for spinal decompression sickness following air dives.

    PubMed

    Douglas, J D; Robinson, C

    1988-07-01

    Enforced delay in treatment of spinal decompression sickness following scuba diving can result in paraplegia. Poor response from initial recompression to 18 m presents the clinician with a difficult management problem. Theoretical objections have been raised to the use of He-O2 as treatment regimen. We report 3 cases that show He-O2 to be an excellent method of treatment in spinal decompression sickness after air diving.

  13. [Scuba diving: barotrauma, decompression sickness, pulmonary contra-indications].

    PubMed

    Héritier, F; Russi, E

    1993-02-01

    The practice of scuba diving is associated with two specific medical problems: barotrauma directly related to changes in ambient pressure, and decompression sickness related to the uptake and the release of inert gases by the body. Neurological symptoms are frequent in severe diving accidents. They may arise following either barotrauma or decompression sickness, and often require urgent treatment in a hyperbaric chamber. Asthma, chronic obstructive pulmonary disease, and spontaneous pneumothorax increase the risk of lung barotrauma and represent contraindications to diving.

  14. 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

  15. Neurovascular Bundle Decompression without Excessive Dissection for Tarsal Tunnel Syndrome

    PubMed Central

    KIM, Kyongsong; ISU, Toyohiko; MORIMOTO, Daijiro; SASAMORI, Toru; SUGAWARA, Atsushi; CHIBA, Yasuhiro; ISOBE, Masahiro; KOBAYASHI, Shiro; MORITA, Akio

    2014-01-01

    Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve and its branches in the tarsal tunnel. We present our less invasive surgical treatment of TTS in 69 patients (116 feet) and their clinical outcomes. The mean follow-up period was 64.6 months. With the patient under local anesthesia we use a microscope to perform sharp dissection of the flexor retinaculum and remove the connective tissues surrounding the posterior tibial nerve and vessels. To prevent postoperative adhesion and delayed neuropathy, decompression is performed to achieve symptom improvement without excessive dissection. Decompression is considered complete when the patient reports intraoperative symptom abatement and arterial pulsation is sufficient. The sensation of numbness and/or pain and of foreign substance adhesion was reduced in 92% and 95% of our patients, respectively. In self-assessments, 47 patients (68%) reported the treatment outcome as satisfactory, 15 (22%) as acceptable, and 7 (10%) were dissatisfied. Of 116 feet, 4 (3%) required re-operation, initial decompression was insufficient in 2 feet and further decompression was performed; in the other 2 feet improvement was achieved by decompression of the distal tarsal tunnel. Our surgical method involves neurovascular bundle decompression to obtain sufficient arterial pulsation. As we use local anesthesia, we can confirm symptom improvement intraoperatively, thereby avoiding unnecessary excessive dissection. Our method is simple, safe, and without detailed nerve dissection and it prevents postoperative adhesion. PMID:25367582

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

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

    PubMed Central

    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

  5. 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.

  6. Therapeutic effects of segmental resection and decompression combined with joint prosthesis on continuous knee osteoarthritis

    PubMed Central

    Xue, Junlai; Wang, Changhong; Liu, Peng; Xie, Xiangchun; Qi, Shan

    2014-01-01

    Objective: To observe the therapeutic effects of segmental resection and decompression combined with joint prosthesis on continuous knee osteoarthritis (OA). Methods: A total of 130 patients with knee OA were selected and randomly divided into an observation group and a control group (n=65). The control group was treated by segmental resection in combination with joint prosthesis, and the observation group was treated by segmental resection and decompression combined with joint prosthesis. They were followed-up for three months. Results: All patients underwent successful surgeries during which no severe complications occurred. During the follow-up period, the overall effective rates of the observation group and the control group were 93.8% and 78.5% respectively, which were not statistically significantly different (p < 0.05). The observation group was significantly less prone to patellar instability, infection and deep vein thrombosis compared with the control group (P < 0.05). On the same day after surgery, the knee joint scores and functional scores of the two groups were similar, which evidently increased three months later, with significant intra-group and inter-group differences (p < 0.05). Conclusion: Combining segmental resection and decompression with joint prosthesis gave rise to satisfactory short-term prognosis by effectively improving the flexion and extension of injured knee and by decreasing complications, thus being worthy of promotion in clinical practice. PMID:25674115

  7. 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

  8. Extremely high fracture rate of a modular acetabular component with a sandwich polyethylene ceramic insertion for THA: a preliminary report.

    PubMed

    Kircher, Jörn; Bader, Rainer; Schroeder, Bettina; Mittelmeier, Wolfram

    2009-09-01

    Improvements of ceramic components and design changes have reduced failure rates over the past 30 years in total hip arthroplasty. We present a series of n = 11 cases with ceramic failure out of n = 113 implantations, from which n = 66 were ceramic-on-ceramic (n = 50 with ceramic insert with sandwich in polyethylene and n = 16 with directly fixed ceramic inlay) and n = 47 ceramic on polyethylene bearings, between 1999 and 2001 after introduction of a new implantation system to the market. The overall fracture rate of ceramic for the whole series (n = 113) was 9.7%. For the combination ceramic head with UHMW-PE (n = 47) the fracture rate was 2.1%. For the combination ceramic with ceramic (n = 66) the fracture rate was 15.2%. For the combination ceramic with ceramic sandwich in PE (n = 50) the failure rate was 18%. Only three patients experienced a trauma. Demography of patients (age, gender, body weight and BMI) was not statistically different between patients with failed ceramics and the rest of the patients making patient-specific risk factors unlikely to be an explanation for the failures. Retrospective X-ray analysis of the cup positioning did not show significant difference between failed and non-failed implants in terms of mean cup inclination and version making also operation-specific factors unlikely to be the only reason of this high failure rate. Therefore, manufacturer-specific factors such as design features may have contributed to this high failure rate. Further analysis of the whole series with biomechanical testing of the retrieved material needs to be performed. PMID:18568354

  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. Age-related differences in valence and arousal ratings of pictures from the International Affective Picture System (IAPS): do ratings become more extreme with age?

    PubMed

    Grühn, Daniel; Scheibe, Susanne

    2008-05-01

    The International Affective Picture System (IAPS) has been widely used in aging-oriented research on emotion. However, no ratings for older adults are available. The aim of the present study was to close this gap by providing ratings of valence and arousal for 504 IAPS pictures by 53 young and 53 older adults. Both age groups rated positive pictures as less arousing, resulting in a stronger linear association between valence and arousal, than has been found in previous studies. This association was even stronger in older than in young adults. Older adults perceived negative pictures as more negative and more arousing and positive pictures as more positive and less arousing than young adults did. This might indicate a dedifferentiation of emotional processing in old age. On the basis of a picture recognition task, we also report memorability scores for individual pictures and how they relate to valence and arousal ratings. Data for all the pictures are archived at www.psychonomic.org/archive/.

  11. An Investigation into the Factors Influencing Extreme-Response Style: Improving Meaning of Translated and Culturally Adapted Rating Scales

    ERIC Educational Resources Information Center

    Arce-Ferrer, Alvaro J.

    2006-01-01

    Translation and cultural adaptation of rating scales are two critical components in testing culturally and/or linguistically heterogeneous populations. Despite the proper use of these scales, challenges typically arise from respondents' language, culture, ratiocination, and characteristics of measurement processes. This study investigated factors…

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. The Impact of Mass Segregation and Star Formation on the Rates of Gravitational-wave Sources from Extreme Mass Ratio Inspirals

    NASA Astrophysics Data System (ADS)

    Aharon, Danor; Perets, Hagai B.

    2016-10-01

    Compact stellar objects inspiraling into massive black holes (MBHs) in galactic nuclei are some of the most promising gravitational-wave (GWs) sources for next-generation GW detectors. The rates of such extreme mass ratio inspirals (EMRIs) depend on the dynamics and distribution of compact objects (COs) around the MBH. Here, we study the impact of mass-segregation processes on EMRI rates. In particular, we provide the expected mass function (MF) of EMRIs, given an initial MF of stellar black holes (SBHs), and relate it to the mass-dependent detection rate of EMRIs. We then consider the role of star formation (SF) on the distribution of COs and its implication on EMRI rates. We find that the existence of a wide spectrum of SBH masses leads to the overall increase of EMRI rates and to high rates of the EMRIs from the most massive SBHs. However, it also leads to a relative quenching of EMRI rates from lower-mass SBHs, and together produces a steep dependence of the EMRI MF on the highest-mass SBHs. SF history plays a relatively small role in determining the EMRI rates of SBHs, since most of them migrate close to the MBH through mass segregation rather than forming in situ. However, the EMRI rate of neutron stars (NSs) can be significantly increased when they form in situ close to the MBH, as they can inspiral before relaxation processes significantly segregate them outward. A reverse but weaker effect of decreasing the EMRI rates from NSs and white dwarfs occurs when SF proceeds far from the MBH.

  1. 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

    2016-09-01

    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.

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

    DOE PAGES

    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

  3. Mesoporous CNT@TiO2-C Nanocable with Extremely Durable High Rate Capability for Lithium-Ion Battery Anodes

    PubMed Central

    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

  4. 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.

  5. Perceived Gender Ratings for High and Low Scorers on the Autism-Spectrum Quotient Consistent with the Extreme Male Brain Account of Autism.

    PubMed

    Tan, Diana Weiting; Russell-Smith, Suzanna N; Simons, Jessica M; Maybery, Murray T; Leung, Doris; Ng, Honey L H; Whitehouse, Andrew J O

    2015-01-01

    The Extreme Male Brain (EMB) theory posits that autistic traits are linked to excessive exposure to testosterone in utero. While findings from a number of studies are consistent with this theory, other studies have produced contradictory results. For example, some findings suggest that rather than being linked to hypermasculinization for males, or defeminization for females, elevated levels of autistic traits are instead linked to more androgynous physical features. The current study provided further evidence relevant to the EMB and androgony positions by comparing groups of males selected for high or low scores on the Autism-spectrum Quotient (AQ) as to the rated masculinity of their faces and voices, and comparable groups of females as to the rated femininity of their faces and voices. The voices of High-AQ males were rated as more masculine than those of Low-AQ males, while the faces of High-AQ females were rated as less feminine than those of Low-AQ females. There was no effect of AQ group on femininity ratings for female voices or on masculinity ratings for male faces. The results thus provide partial support for a link between high levels of autistic-like traits and hypermasculinization for males and defeminization for females, consistent with the EMB theory.

  6. Survival rate and neurodevelopmental outcome of extremely premature babies: an 8-year experience of an Italian single neonatal tertiary care center.

    PubMed

    Uccella, Sara; De Carli, Agnese; Sirgiovanni, Ida; Schiavolin, Paola; Damiano, Giuseppe; Ghirardi, Beatrice; Maglioli Carpano, Francesca; Bassi, Laura; Gangi, Silvana; Picciolini, Odoardo; Fumagalli, Monica; Mosca, Fabio

    2015-01-01

    Extremely preterm babies are at major risk for adverse neurodevelopmental outcome, being the gestational age (GA) the main determinant for a good-quality survival. Aim of this retrospective study was to investigate the neurodevelopmental outcome in a population of extremely preterm babies admitted to a single neonatal tertiary care unit over an 8-year period. All babies born between 23+0 and 25+6 weeks of GA from January 2003 until December 2010 were retrospectively enrolled. Perinatal and neonatal variables were recorded. Motor and cognitive development was assessed using the neurofunctional scale (NFS) and the Griffith's scales at 2 years. Fifty-five out of 122 infants survived to discharge. Survival rates doubled for each additional gestational week from 23 to 25: 16%, 38% and 74% at 23, 24 and 25 weeks GA respectively. Forty-six infants were evaluated at 2 years. A poor cognitive and motor outcome was observed in all babies born at 23 weeks. Griffith's general quotient (GQ) was ≥76 in 62% and ≥88 in 33% of babies born between 24 and 25 weeks. No severe motor disabilities were found in 81% of babies born between 24 and 25 weeks. Preterm premature rupture of membranes, absence of prenatal steroids, intrauterine growth restriction, male, lower GA and major brain abnormalities at magnetic resonance imaging (MRI) were significantly associated with worse NFS and lower mean GQ at 2 years of age. GA, gender and abnormal MRI findings remained significantly associated with impaired NFS at the multivariate analysis. Survival rates and neurodevelopmental outcome improved with each week of GA. These results are relevant for clinicians counselling families facing an unavoidable extremely preterm birth. PMID:26714779

  7. 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.

  8. Observed Rates of Lower Extremity Stress Fractures After Implementation of the Army Physical Readiness Training Program at JBSA Fort Sam Houston.

    PubMed

    Chalupa, Robyn L; Aberle, Curtis; Johnson, Anthony E

    2016-01-01

    Millions of dollars are lost each year to the US military in medical discharges from injuries sustained in the initial training of recruits. Most medical discharges in recruits are related to musculoskeletal overuse injuries, including stress fractures. Any strategies that can reduce injury rates are also likely to reduce rates of medical discharge. This study evaluated the Army Physical Readiness Training (PRT) program which was established to provide a method of physical fitness training that would reduce the number of preventable injuries. We conducted a retrospective study to evaluate the number of lower extremity stress fractures that were diagnosed in the 6 months prior to and 6 months following the implementation of the PRT program. Electronic medical records were queried for specific diagnoses of stress fractures to the pelvis, femoral neck, femoral shaft, tibia, fibula, tarsals and metatarsals. The observed number of diagnoses in each time period were compared using the χ² method. Decrease was shown not only in the overall occurrence of stress fractures, but specifically in the occurrence of stress fractures of the femoral neck, femoral shaft, and tarsals. Our study was able to show a correlation between the PRT program and a decrease in the observed occurrence of lower extremity stress fractures.

  9. 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.

  10. Simple and Fast Continuous Estimation Method of Respiratory Frequency During Sleep using the Number of Extreme Points of Heart Rate Time Series

    NASA Astrophysics Data System (ADS)

    Yoshida, Yutaka; Yokoyama, Kiyoko; Ishii, Naohiro

    It is reported that frequency component of approximately 0.25Hz of heart rate time series (RSA) is corresponding to the respiratory frequency. In this paper, we proposed that continuous estimation method of respiratory fequency during sleep using the number of extreme points of heart rate time series in real time. Equation for calculation of the method is very simple and the method can continuously calculate frequency by window width of about 18 beats. To evaluate accuracy of proposal method, RSA frequency was calculated using proposal method from the heart rate time series during supine rest. Result, minimum error rate was observed when RSA had time lag for about 11s and error rate was about 13.8%. Result of estimating RSA frequency time series during sleep, it varied regularly during non-REM and varied irregularly during REM. This result is similar as report of previous study about respiratory variability during sleep. Therefore, it is considered that proposal method possible to apply respiratory monitoring system during sleep.

  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.

  12. 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

  13. 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

  14. Mechanisms underlying spinal cord damage in decompression sickness.

    PubMed

    Hallenbeck, J M; Bove, A A; Elliott, D H

    1975-04-01

    Decompression sickness, which damaged the spinal cord, was produced in anesthetized dogs using a compression chamber. Cerebrospinal fluid pressure and several intravascular and intracardiac pressures were monitored during the course of the simulated dives. Manometric responses to forcible lung inflation and abdominal compression were measured both predive and postdive after signs of spinal cord damage were evident. Cinevenography of the epidural vertebral venous system was performed both predive and postdive. Histopathologic studies of the brains and cords of both predive and postdive. Histopathologic studies of the brains and cords of paretic animals were carried out. The results indicate that the epidural vertebral venous system becomes obstructed during spinal cord damaging decompression sickness and strongly suggests that spinal cord infarction in decompression sickness is caused by obstruction of cord venous drainage at the level of the epidural vertebral venous system. PMID:1168317

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

    PubMed

    Allan, G Michael; Kenny, David

    2003-10-14

    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.

  16. [Inner ear decompression sickness following a scuba dive].

    PubMed

    Satoh, M; Kitahara, S; Inouye, T; Ikeda, T

    1992-04-01

    Inner ear decompression sickness (IEDCS) is one form of Type II decompression sickness. Most cases of IEDCS have been associated with saturation dives, so there are very few reports of occurrence following shallow scuba dives. We present here the case of a diver who suffered from IEDCS following a shallow scuba dive (30m), and was successfully treated by the protocol outlined in U.S. Navy treatment table 6. This case suggests that there is the possibility of occurrence of IEDCS, even following a shallow scuba dive, if proper decompression procedures are not adhered to. In addition, detailed analysis of diving profiles should be used to distinguish the inner ear dysfunction seen in some divers from inner ear barotrauma which may be attributable to IEDCS.

  17. Arthroscopic suprascapular nerve decompression: transarticular and subacromial approach.

    PubMed

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

    2012-12-01

    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.

  18. 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.

  19. Operation Everest II: an indication of deterministic chaos in human heart rate variability at simulated extreme altitude.

    PubMed

    Yamamoto, Y; Hughson, R L; Sutton, J R; Houston, C S; Cymerman, A; Fallen, E L; Kamath, M V

    1993-01-01

    It has been shown that fluctuation of human heartbeat intervals (heart rate variability, HRV) reflects variations in autonomic nervous system activity. We studied HRV at simulated altitudes of over 6000 m from Holter electrocardiograms recorded during the Operation Everest II study (Houston et al. 1987). Stationary, approximately 30-min segments of HRV data from six subjects at sea level and over 6000 m were supplied to (1) spectral analysis to evaluate sympathetic and parasympathetic nervous system (SNS, PNS) activity, (2) the analysis of Poincaré section of the phase space trajectory reconstructed on a delayed coordinate system to evaluate whether there was fluctuation with deterministic dynamics, (3) the estimation of the correlation dimension to evaluate a static property of putative attractors, and (4) the analysis of nonlinear predictability of HRV time series which could reflect a dynamic property of the attractor. Unlike HRV at sea level, the recordings at over 6000 m showed a strong periodicity (period of about 20 s) with small cycle-to-cycle perturbation. When this perturbation was expressed on a Poincaré section, it seemed to be likely that the perturbation itself obeyed a deterministic law. The correlation dimensions of these recordings showed low dimensional values (3.5 +/- 0.4, mean +/- SD), whereas those of the isospectral surrogates showed significantly (P < 0.05) higher values (5.3 +/- 0.5) with embedding dimensions of 5.6 +/- 0.9.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Magnetic resonance findings in scuba diving-related spinal cord decompression sickness.

    PubMed

    Sparacia, G; Banco, A; Sparacia, B; Midiri, M; Brancatelli, G; Accardi, M; Lagalla, R

    1997-06-01

    Scuba diving is associated with risk of severe decompression sickness (DCS type II), which results from rapid reduction of the environmental pressure sufficient to cause the formation into tissue or blood of inert gas bubbles previously loaded within tissues as a soluble phase. DCS type II constitutes a unique subset of ischemic insults to the central nervous system (CNS) with primarily involvement of the spinal cord. Ten patients with diving-related barotrauma underwent neurologic examination. Two of them presented progressive sensory and motor loss in the extremities at admission and were presumed affected by spinal cord DCS. Magnetic resonance imaging (MRI) demonstrated abnormalities in the white-matter tracts of the spinal cord in these patients, in each case corresponding to an area of the cord believed to be clinically involved. After a course of therapeutic recompressions, one patient was able to stand and walk a short distance, and MRI revealed a decreased extension of areas of spinal cord abnormalities. MRI has proved to be reliable in the detection of pathologic changes of spinal cord decompression sickness that were previously undetectable by other neuroimaging methods and also has proved to be useful in the follow-up during therapeutic hyperbaric recompressions.

  1. 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

  2. Spinal Cord Decompression Sickness in a Sport Scuba Diver.

    PubMed

    Zwingelberg, K M

    1981-10-01

    In brief: A 26-year-old diver suffered spinal cord decompression sickness even though he did not exceed the time and depth limits set in standard US Navy diving tables. This case shows that when dives are strenuous and almost reach time and depth limits they may exceed the parameters of the tables. The case also illustrates the importance of rapid diagnosis and hyperbaric oxygen treatment of pressure-related diving casualties. The author says optimum treatment of decompression sickness depends on a high level of suspicion, an accurate diving history, and prompt treatment with hyperbaric oxygen.

  3. Inner ear decompression sickness following a shallow scuba dive.

    PubMed

    Reissman, P; Shupak, A; Nachum, Z; Melamed, Y

    1990-06-01

    Inner Ear Decompression Sickness (IEDCS)--manifested by tinnitus, vertigo, nausea, vomiting, and hearing loss--is usually associated with deep air or mixed gas dives, and accompanied by other CNS symptoms of decompression sickness (DCS). Early recompression treatment is required in order to avoid permanent inner ear damage. We present an unusual case of a scuba diver suffering from IEDCS as the only manifestation of DCS following a short shallow scuba dive, successfully treated by U.S. Navy treatment table 6 and tranquilizers. This case suggests that diving medical personnel should be more aware of the possible occurrence of IEDCS among the wide population of sport scuba divers.

  4. Pathophysiology and treatment of decompression sickness and gas embolism.

    PubMed

    Loewenherz, J W

    1992-09-01

    Decompression sickness and cerebral gas embolism can present as dramatic and profound sudden onset injuries in patients engaged in tunnel work and compressed gas diving, including scuba. The history and management of these illnesses span centuries. The pathophysiology relates to occurrence of gas bubbles in extrapulmonic sites. Decompression sickness is due to supersaturation of the tissue with dissolved gas and subsequent evolution of gas bubbles. Gas embolism results from the direct transit of molecular gas from a pulmonary or intravascular origin into the arterial circulation causing occlusion of a distal locus. Treatment relates to increasing hydrostatic pressure, thus maximizing the gradient for gas reabsorption and dissolution and subsequently gas excretion via the lungs.

  5. 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.

  6. Oxygen uptake, heart rate, perceived exertion, and integrated electromyogram of the lower and upper extremities during level and Nordic walking on a treadmill

    PubMed Central

    2013-01-01

    The purpose of this study was to characterize responses in oxygen uptake ( V·O2), heart rate (HR), perceived exertion (OMNI scale) and integrated electromyogram (iEMG) readings during incremental Nordic walking (NW) and level walking (LW) on a treadmill. Ten healthy adults (four men, six women), who regularly engaged in physical activity in their daily lives, were enrolled in the study. All subjects were familiar with NW. Each subject began walking at 60 m/min for 3 minutes, with incremental increases of 10 m/min every 2 minutes up to 120 m/min V·O2 , V·E and HR were measured every 30 seconds, and the OMNI scale was used during the final 15 seconds of each exercise. EMG readings were recorded from the triceps brachii, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior muscles. V·O2 was significantly higher during NW than during LW, with the exception of the speed of 70 m/min (P < 0.01). V·E and HR were higher during NW than LW at all walking speeds (P < 0.05 to 0.001). OMNI scale of the upper extremities was significantly higher during NW than during LW at all speeds (P < 0.05). Furthermore, the iEMG reading for the VL was lower during NW than during LW at all walking speeds, while the iEMG reading for the BF and GA muscles were significantly lower during NW than LW at some speeds. These data suggest that the use of poles in NW attenuates muscle activity in the lower extremities during the stance and push-off phases, and decreases that of the lower extremities and increase energy expenditure of the upper body and respiratory system at certain walking speeds. PMID:23406834

  7. No changes in lung function after a saturation dive to 2.5 MPa with intermittent reduction in Po2 during decompression.

    PubMed

    Thorsen, E; Segadal, K; Stuhr, L E B; Troland, K; Grønning, M; Marstein, S; Hope, A

    2006-10-01

    Decompression stress and exposure to hyperoxia may cause a reduction in transfer factor of the lung for carbon monoxide and in maximal aerobic capacity after deep saturation dives. In this study lung function and exercise capacity were assessed before and after a helium-oxygen saturation dive to a pressure of 2.5 MPa where the decompression rate was reduced compared with previous deep dives, and the hyperoxic exposure was reduced by administering oxygen intermittently at pressures of 50 and 30 kPa during decompression. Eight experienced divers of median age 41 years (range 29-48) participated in the dive. The incidence of venous gas microemboli was low compared with previous deep dives. Except for one subject having treatment for decompression sickness, no changes in lung function or angiotensin converting enzyme, a marker of pulmonary endothelial cell damage, were demonstrated. The modified diving procedures with respect to decompression rate and hyperoxic exposure may have contributed to the lack of changes in lung function in this dive compared with previous deep saturation dives.

  8. 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.

  9. 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...

  10. 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...

  11. 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 following table gives the depth versus bottom time limits for single, no-decompression, air dives...

  12. Effects of heterogeneous structure and diffusion permeability of body tissues on decompression gas bubble dynamics.

    PubMed

    Nikolaev, V P

    2000-07-01

    To gain insight into the special nature of gas bubbles that may form in astronauts, aviators and divers, we developed a mathematical model which describes the following: 1) the dynamics of extravascular bubbles formed in intercellular cavities of a hypothetical tissue undergoing decompression; and 2) the dynamics of nitrogen tension in a thin layer of intercellular fluid and in a thick layer of cells surrounding the bubbles. This model is based on the assumption that, due to limited cellular membrane permeability for gas, a value of effective nitrogen diffusivity in the massive layer of cells in the radial direction is essentially lower compared to conventionally accepted values of nitrogen diffusivity in water and body tissues. Due to rather high nitrogen diffusivity in intercellular fluid, a bubble formed just at completion of fast one-stage reduction of ambient pressure almost instantly grows to the size determined by the initial volume of the intercellular cavity, surface tension of the fluid, the initial nitrogen tension in the tissue, and the level of final pressure. The rate of further bubble growth and maximum bubble size depend on comparatively low effective nitrogen diffusivity in the cell layer, the tissue perfusion rate, the initial nitrogen tension in the tissue, and the final ambient pressure. The tissue deformation pressure performs its conservative action on bubble dynamics only in a limited volume of tissue (at a high density of formed bubbles). Our model is completely consistent with the available data concerning the random latency times to the onset of decompression sickness (DCS) symptoms associated with hypobaric decompressions simulating extravehicular activity. We believe that this model could be used as a theoretical basis for development of more adequate methods for the DCS risk prediction.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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

  18. Air embolism and decompression sickness in scuba divers.

    PubMed

    Whitcraft, D D; Karas, S

    1976-05-01

    The recognition and prompt treatment of air embolism and decompression sickness by the emergency physician can do much to reverse the unfavorable outcome of these two medical emergencies. Recognition depends on the physician maintaining a high index of suspicion. While the primary treatment for these disorders is recompression, other forms of therapy are outlined which must be instituted promptly.

  19. Does arthroscopic subacromial decompression improve quality of life

    PubMed Central

    Whiteman, A; Wilson, J; Paul, E; Roy, B

    2015-01-01

    Introduction There has been a significant rise in the volume of subacromial decompression surgery performed in the UK. This study aimed to determine whether arthroscopic subacromial decompression improves health related quality of life in a cost effective manner. Methods Patients undergoing arthroscopic subacromial decompression surgery for impingement were enrolled between 2012 and 2014. The Oxford shoulder score and the EQ-5D™ instruments were completed prior to and following surgery. A cost–utility analysis was performed. Results Eighty-three patients were eligible for the study with a mean follow-up duration of 15 months (range: 4–27 months). The mean Oxford shoulder score improved by 13 points (95% confidence interval [CI]: 11–15 points). The mean health utility gain extrapolated from the EQ-5D™ questionnaire improved by 0.23 (95% CI: 0.16–0.30), translating to a minimum cost per QALY of £5,683. Conclusions Subacromial decompression leads to significant improvement in function and quality of life in a cost effective manner. This provides justification for its ongoing practice by appropriately trained shoulder surgeons in correctly selected patients. PMID:26263808

  20. 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

  1. Probabilistic modelling for estimating gas kinetics and decompression sickness risk in pigs during H2 biochemical decompression.

    PubMed

    Fahlman, Andreas; Kayar, Susan R

    2003-07-01

    We modelled the kinetics of H2 flux during gas uptake and elimination in conscious pigs exposed to hyperbaric H2. The model used a physiological description of gas flux fitted to the observed decompression sickness (DCS) incidence in two groups of pigs: untreated controls, and animals that had received intestinal injections of H2-metabolizing microbes that biochemically eliminated some of the H2 stored in the pigs' tissues. To analyse H2 flux during gas uptake, animals were compressed in a dry chamber to 24 atm (ca 88% H2, 9% He, 2% O2, 1% N2) for 30-1440 min and decompressed at 0.9 atm min(-1) (n = 70). To analyse H2 flux during gas elimination, animals were compressed to 24 atm for 3 h and decompressed at 0.45-1.8 atm min(-1) (n = 58). Animals were closely monitored for 1 h post-decompression for signs of DCS. Probabilistic modelling was used to estimate that the exponential time constant during H2 uptake (tau(in)) and H2 elimination (tau(out)) were 79 +/- 25 min and 0.76 +/- 0.14 min, respectively. Thus, the gas kinetics affecting DCS risk appeared to be substantially faster for elimination than uptake, which is contrary to customary assumptions of gas uptake and elimination kinetic symmetry. We discuss the possible reasons for this asymmetry, and why absolute values of H2 kinetics cannot be obtained with this approach.

  2. [Effects of nitrogen fertilization rate and planting density on cotton boll biomass and nitrogen accumulation in extremely early maturing cotton region of Northeast China].

    PubMed

    Wang, Zi-Sheng; Wu, Xiao-Dong; Gao, Xiang-Bin; Xu, Min; Shen, Dan; Jin, Lu-Lu; Zhou, Zhi-Guo

    2012-02-01

    Taking cotton cultivars Liaomian 19 and NuCoTN 33B as test materials, a field experiment was conducted to study the effects of nitrogen fertilization rate (0, 240 and 480 kg x hm(-2)) and planting density (75000, 97500 and 120000 plants x hm(-2)) on the boll biomass and nitrogen accumulation in the extremely early maturing cotton region of Northeast China. With the growth and development of cotton, the biomass and nitrogen accumulation of cotton boll, cotton seed, and cotton fiber varied in 'S' shape. Both nitrogen fertilization rate and planting density had significant effects on the dynamic characteristics of boll biomass and nitrogen accumulation, and on the fiber yield and quality. In treatment 240 kg x hm(-2) and 97500 plants x hm(-2), the biomass of single boll, cotton seed and cotton fiber was the maximum, the starting time and ending time of the rapid accumulation period of the biomass and nitrogen were earlier but the duration of the accumulation was shorter, the rapid accumulation speed of the biomass was the maximum, and the distribution indices of the biomass and nitrogen were the lowest in boll shell but the highest in cotton seed and cotton fiber.

  3. 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.

  4. 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

  5. Trigemino-cardiac reflex during microvascular trigeminal decompression in cases of trigeminal neuralgia.

    PubMed

    Schaller, Bernhard

    2005-01-01

    The trigemino-cardiac reflex (TCR) is a well-recognized phenomenon consisting of bradycardia, arterial hypotension, apnea, and gastric hypermotility during ocular surgery or other manipulations in and around the orbit. Thus far, it could bee shown that central stimulation of the trigeminal nerve during transsphenoidal surgery and surgery for tumors in the cerebellopontine angle can lead to TCR. In cases of microvascular trigeminal decompression for trigeminal neuralgia, no data of the possible occurrence of TCR are available. TCR was defined as a drop in mean arterial blood pressure (MABP) and the heart rate (HR) of more than 20% to the baseline values before the stimulus and coinciding with the manipulation of the trigeminal nerve. Electronic anesthetic recorded perioperative HR and MABP values were reviewed retrospectively in 28 patients who received microvascular trigeminal decompression in cases of trigeminal neuralgia and were divided into two subgroups on the basis of occurrence of TCR during surgery. Of the 28 patients, 5 (18%) showed evidence of TCR during manipulation at the trigeminal radix by separation from microvascular structures. Their HR fell 46% and their MABP 57% during operative procedures near the trigeminal nerve as compared with levels immediately before the stimulus. After cessation of manipulation, HR and MABP returned (spontaneously) to levels before the stimulus. Risk factors of TCR were compared with results from the literature. In conclusion, the present results give evidence of TCR during manipulation of the central part of the trigeminal nerve during microvascular trigeminal decompression in cases of trigeminal neuralgia under a standardized anesthetic protocol.

  6. 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

  7. 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

  8. Scuba decompression illness and diving fatalities in an overseas military community.

    PubMed

    Arness, M K

    1997-04-01

    A retrospective study of scuba decompression illness (DCI) and fatalities in the U.S. military community on Okinawa Island, Japan, was performed for 1989-95. Some 94 cases of diving DCI, including 10 cases of cerebral air-gas embolism (CAGE), and 9 diving fatalities were reported, for an annual incidence of 13.4 DCI events and 1.3 fatalities per 100,000 dives. The overall estimated incidence of scuba DCI was estimated to be 1/7400 dives, with an annual incidence of undeserved DCI of 1/37,300, and a fatality rate of 1/76,900. A review of treatment dives revealed a 10% overdiagnosis rate in cases treated for presumed DCI. A bimodal distribution of DCI accidents was observed for depths deeper or shallower than 24.6m/80FSW (feet of sea water). Increased risk of DCI in diving deeper than 24.6m/80FSW was associated with violations of no-decompression limits (NDL), while other risk factors were associated with diving to less than 24.6m/80FSW. NDL violations accounted for only 24/94 (26%) of all DCI accidents. Treatment of divers with hyperbaric oxygen (HBOT) led to complete recovery in 91% of cases, but of those divers requiring retreatment with HBOT, 67% had chronic residua of DCI. Selected illustrative and interesting cases are discussed.

  9. Nitrogen partial pressures in man after decompression from simulated scuba dives at rest and during exercise.

    PubMed

    Radermacher, P; Santak, B; Muth, C M; Wenzel, J; Hampe, P; Vogt, L; Hahn, M; Falke, K J

    1990-11-01

    In 5 subjects arterial and central venous nitrogen partial pressures (PN2) were measured after decompression from a chamber dive following a decompression schedule for scuba diving. The simulated dives consisted of exposure to air at 6 bar for 30 min corresponding to a depth of 50 m. Afterward the subjects were decompressed with decompression stops at 2.5, 2.2, 1.9, 1.6, and 1.3 bar with a total decompression time of 67 min. In 3 of the subjects the measurements were repeated after they had exercised (workload 75 W) during bottom time. Immediately after decompression and every 40 min until Minute 240 arterial and central venous blood samples were analyzed for PN2 using a manometric Van Slyke apparatus. Venous PN2 remained elevated until 160 min after decompression, indicating still incomplete nitrogen washout for at least 2 h after decompression had been accomplished. We did not find any difference in PN2 values after decompression from dives at rest and after exercise. Applying a computer program based on a wide range of theoretical tissue half-times nitrogen elimination proved to be consistent with Haldanian theories when using our decompression profile. Our data confirm that nitrogen elimination is prolonged after decompression from simulated dives at rest and after exercise.

  10. A deep stop during decompression from 82 fsw (25 m) significantly reduces bubbles and fast tissue gas tensions.

    PubMed

    Marroni, A; Bennett, P B; Cronje, F J; Cali-Corleo, R; Germonpre, P; Pieri, M; Bonuccelli, C; Balestra, C

    2004-01-01

    In spite of many modifications to decompression algorithms, the incidence of decompression sickness (DCS) in scuba divers has changed very little. The success of stage, compared to linear ascents, is well described yet theoretical changes in decompression ratios have diminished the importance of fast tissue gas tensions as critical for bubble generation. The most serious signs and symptoms of DCS involve the spinal cord, with a tissue half time of only 12.5 minutes. It is proposed that present decompression schedules do not permit sufficient gas elimination from such fast tissues, resulting in bubble formation. Further, it is hypothesized that introduction of a deep stop will significantly reduce fast tissue bubble formation and neurological DCS risk. A total of 181 dives were made to 82 fsw (25 m) by 22 volunteers. Two dives of 25 min and 20 min were made, with a 3 hr 30 min surface interval and according to 8 different ascent protocols. Ascent rates of 10, 33 or 60 fsw/min (3, 10, 18 m/min) were combined with no stops or a shallow stop at 20 fsw (6 m) or a deep stop at 50 fsw (15 m) and a shallow at 20 fsw (6 m). The highest bubbles scores (8.78/9.97), using the Spencer Scale (SS) and Extended Spencer Scale (ESS) respectively, were with the slowest ascent rate. This also showed the highest 5 min and 10 min tissue loads of 48% and 75%. The lowest bubble scores (1.79/2.50) were with an ascent rate of 33 fsw (10 m/min) and stops for 5 min at 50 fsw (15 m) and 20 fsw (6 m). This also showed the lowest 5 and 10 min tissue loads at 25% and 52% respectively. Thus, introduction of a deep stop significantly reduced Doppler detected bubbles together with tissue gas tensions in the 5 and 10 min tissues, which has implications for reducing the incidence of neurological DCS in divers.

  11. Mortality rates at 10 years are higher in diabetic than in non-diabetic patients with chronic lower extremity peripheral arterial disease

    PubMed Central

    Mueller, Thomas; Hinterreiter, Franz; Poelz, Werner; Haltmayer, Meinhard; Dieplinger, Benjamin

    2016-01-01

    Patients with lower extremity peripheral artery disease (PAD) have a substantially increased risk for mortality as compared to healthy individuals. We aimed to evaluate the risk for all-cause mortality in PAD patients and in healthy controls during a 10-year follow-up period. Our hypothesis was that the mortality rates at 10 years would differ in diabetic and non-diabetic PAD patients. Our study group consisted of 331 consecutive patients with symptomatic PAD <75 years of age admitted to a tertiary care hospital, including 216 patients without diabetes and 115 with diabetes. Control subjects without atherosclerotic disease were matched to the patients in a 1:1 design by sex, age, and diabetes mellitus status. The outcome measure was all-cause mortality at 10 years. Mortality rates at 10 years were 29% in non-diabetic PAD patients versus 14% in age- and sex-matched non-diabetic controls (risk ratio (RR), 2.31; 95% confidence interval (CI), 1.54–3.47; p<0.001), and 58% in diabetic PAD patients versus 19% in age- and sex-matched diabetic controls (RR, 4.06; 95% CI, 2.67–6.18; p<0.001). Further, PAD patients with diabetes had a significantly increased risk for death within 10 years than did the non-diabetic PAD patients (RR, 2.51; 95% CI, 1.72–3.66; p<0.001). Diabetes was independently associated with outcome, and was the strongest predictor of death in multivariate Cox proportional hazards regression. We conclude that mortality rates at 10 years differ in PAD patients <75 years old with and without diabetes. Our findings suggest that future studies should apply distinct risk assessment strategies in the two PAD subgroups. PMID:27067137

  12. Dynamics of upper mantle rocks decompression melting above hot spots under continental plates

    NASA Astrophysics Data System (ADS)

    Perepechko, Yury; Sorokin, Konstantin; Sharapov, Victor

    2014-05-01

    Numeric 2D simulation of the decompression melting above the hot spots (HS) was accomplished under the following conditions: initial temperature within crust mantle section was postulated; thickness of the metasomatized lithospheric mantle is determined by the mantle rheology and position of upper asthenosphere boundary; upper and lower boundaries were postulated to be not permeable and the condition for adhesion and the distribution of temperature (1400-2050°C); lateral boundaries imitated infinity of layer. Sizes and distribution of lateral points, their symmetry, and maximum temperature varied between the thermodynamic condition for existences of perovskite - majorite transition and its excess above transition temperature. Problem was solved numerically a cell-vertex finite volume method for thermo hydrodynamic problems. For increasing convergence of iterative process the method of lower relaxation with different value of relaxation parameter for each equation was used. The method of through calculation was used for the increase in the computing rate for the two-layered upper mantle - lithosphere system. Calculated region was selected as 700 x (2100-4900) km. The time step for the study of the asthenosphere dynamics composed 0.15-0.65 Ma. The following factors controlling the sizes and melting degree of the convective upper mantle, are shown: a) the initial temperature distribution along the section of upper mantleb) sizes and the symmetry of HS, c) temperature excess within the HS above the temperature on the upper and lower mantle border TB=1500-2000oC with 5-15% deviation but not exceed 2350oC. It is found, that appearance of decompression melting with HS presence initiate primitive mantle melting at TB > of 1600oC. Initial upper mantle heating influence on asthenolens dimensions with a constant HS size is controlled mainly by decompression melting degree. Thus, with lateral sizes of HS = 400 km the decompression melting appears at TB > 1600oC and HS

  13. 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.

  14. 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%.

  15. 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

  16. 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.

  17. Doppler bubble detection and decompression sickness: a prospective clinical trial.

    PubMed

    Bayne, C G; Hunt, W S; Johanson, D C; Flynn, E T; Weathersby, P K

    1985-09-01

    Decompression sickness in human beings exposed to high ambient pressure is thought to follow from gas bubble formation and growth in the body during return to low pressure. Detection of Doppler-shifted ultrasonic reflections in major blood vessels has been promoted as a noninvasive and sensitive indicator of the imminence of decompression sickness. We have conducted a double-blind, prospective clinical trial of Doppler ultrasonic bubble detection in simulated diving using 83 men, of whom 8 were stricken and treated for the clinical disease. Diagnosis based only on the Doppler signals had no correlation with clinical diagnosis. Bubble scores were only slightly higher in the stricken group. The Doppler technique does not appear to be of diagnostic value in the absence of other clinical information.

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

    PubMed

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

    1975-07-01

    This study has shown that repetitive exchanges between the American Apollo space vehicle atmosphere of 100% oxygen at 5 psia (258 torr) and the Russian Soyuz spacecraft atmosphere of 30% oxygen-70% nitrogen at 10 psia (523 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.

  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. 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.

  1. 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.

  2. Microbubbles are detected prior to larger bubbles following decompression.

    PubMed

    Swan, J G; Wilbur, J C; Moodie, K L; Kane, S A; Knaus, D A; Phillips, S D; Beach, T L; Fellows, A M; Magari, P J; Buckey, J C

    2014-04-01

    Using dual-frequency ultrasound (DFU), microbubbles (<10 μm diameter) have been detected in tissue following decompression. It is not known if these microbubbles are the precursors for B-mode ultrasound-detectable venous gas emboli (bmdVGE). The purpose of this study was to determine if microbubbles could be detected intravascularly postdecompression and to investigate the temporal relationship between microbubbles and larger bmdVGE. Anesthetized swine (n = 15) were exposed to 4.0-4.5 ATA for 2 h, followed by decompression to 0.98 ATA. Microbubble presence and VGE grade were measured using DFU and B-mode ultrasound, respectively, before and for 1 h postdecompression, approximately every 4-5 min. Microbubbles appeared in the bloodstream postdecompression, both in the presence and absence of bmdVGE. In swine without bmdVGE, microbubbles remained elevated for the entire 60-min postdecompression period. In swine with bmdVGE, microbubble signals were detected initially but then returned to baseline. Microbubbles were not detected with the sham dive. Mean bmdVGE grade increased over the length of the postdecompression data collection period. Comparison of the two response curves revealed significant differences at 5 and 10 min postdecompression, indicating that microbubbles preceded bmdVGE. These findings indicate that decompression-induced microbubbles can 1) be detected intravascularly at multiple sites, 2) appear in the presence and absence of bmdVGE, and 3) occur before bmdVGE. This supports the hypothesis that microbubbles precede larger VGE bubbles. Microbubble presence may be an early marker of decompression stress. Since DFU is a low-power ultrasonic method, it may be useful for operational diving applications.

  3. 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..., 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...

  4. Hemimasticatory spasm treated with microvascular decompression of the trigeminal nerve.

    PubMed

    Chon, Kyu-Hyon; Lee, Jong-Myong; Koh, Eun-Jeong; Choi, Ha-Young

    2012-09-01

    Hemimasticatory spasm is a very rare disorder of the trigeminal nerve characterized by paroxysmal involuntary contraction of the jaw-closing muscles. The mechanisms leading to hemimasticatory spasm are still unclear. Recently, injection of botulinum toxin has become the treatment of choice due to its excellent results. We report a case of a successful treatment of hemimasticatory spasm via microvascular decompression of the motor branch of the trigeminal nerve.

  5. 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...

  6. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 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...

  7. Early decompressive hemicraniectomy in fulminant herpes simplex encephalitis.

    PubMed

    Maraite, N; Mataigne, F; Pieri, V; Dang, T; Diederich, N J

    2010-01-01

    Herpes encephalitis can be a life-threatening condition, despite early instauration of acyclovir treatment. In particular patients may succumb to rapidly progressive cerebral oedema. We report a 66-year patient with a Glasgow Coma Score (GCS) of 6 and incipient uncus herniation of the right temporal lobe on the third day. Decompressive hemicraniectomy was immediately performed. The long-term outcome was satisfactory with unassisted gait and a Barthel Index score of 70 after 9 months.

  8. Early decompressive hemicraniectomy in fulminant herpes simplex encephalitis.

    PubMed

    Maraite, N; Mataigne, F; Pieri, V; Dang, T; Diederich, N J

    2009-01-01

    Herpes encephalitis can be a life-threatening condition, despite early instauration of acyclovir treatment. In particular patients may succumb to rapidly progressive cerebral oedema. We report a 66-year patient with a Glasgow Coma Score (GCS) of 6 and incipient uncus herniation of the right temporal lobe on the third day. Decompressive hemicraniectomy was immediately performed. The long-term outcome was satisfactory with unassisted gait and a Barthel Index score of 70 after 9 months.

  9. 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.

  10. 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.

  11. The Effect of Microvascular Decompression for Hemifacial Spasm Caused by Vertebrobasilar Dolichoectasia

    PubMed Central

    Kang, Jeong-Han; Kang, Dong-Wan; Chung, Sang Sup

    2012-01-01

    Objective Hemifacial spasm (HFS) caused by vertebrobasilar dolichoectasia (VBD) is very rare, and in theses cases, it is difficult to decompress the nerve from its vascular compression. The objective of this study was to investigate the outcome of microvascular decompression (MVD) for HFS caused by VBD. Methods There were 10 patients of HFS caused by VBD at our hospital between September 1978 and September 2008. We evaluated magnetic resonance angiography (MRA) and time of flight magnetic resonance imaginge (TOF MRI) findings using the criteria for VBD. We compared the clinical outcomes of MVD for the 10 patients with VBD with the overall outcomes of the total 2058 MVDs performed for HFS. Results The results of MVD for HFS caused by VBD were successful in 90.9% of cases. The postoperative complication rate in VBD was 45.5%. Offending vessels in patients with VBD were identified visually during surgery. Adverse effects after MVD were found in 4 patients. We found that the diameter of VBD was significantly greater in patients with complications than in those with no complications (p=0.028). Conclusion Our data shows that MVD may be a good treatment modality for HFS caused by VBD but care must be taken to avoid adverse effects from the procedure. It is important to detach the dolichoectatic artery from its surrounding structures sufficiently to allow it to be easily movable. In addition, attempts should be made to lessen the retraction of the cerebellum during release of the dolichoectatic artery. PMID:23091664

  12. A new class of biophysical models for predicting the probability of decompression sickness in scuba diving.

    PubMed

    Goldman, Saul

    2007-08-01

    Interconnected compartmental models have been used for decades in physiology and medicine to account for the observed multi-exponential washout kinetics of a variety of solutes (including inert gases) both from single tissues and from the body as a whole. They are used here as the basis for a new class of biophysical probabilistic decompression models. These models are characterized by a relatively well-perfused, risk-bearing, central compartment and one or two non-risk-bearing, relatively poorly perfused, peripheral compartment(s). The peripheral compartments affect risk indirectly by diffusive exchange of dissolved inert gas with the central compartment. On the basis of the accuracy of their respective predictions beyond the calibration regime, the three-compartment interconnected models were found to be significantly better than the two-compartment interconnected models. The former, on the basis of a number of criteria, was also better than a two-compartment parallel model used for comparative purposes. In these latter comparisons, the models all had the same number of fitted parameters (four), were based on linear kinetics, had the same risk function, and were calibrated against the same dataset. The interconnected models predict that inert gas washout during decompression is relatively fast, initially, but slows rapidly with time compared with the more uniform washout rate predicted by an independent parallel compartment model. If empirically verified, this may have important implications for diving practice.

  13. Intramedullary decompression with condylectomy for intractable plantar keratoma.

    PubMed

    Roven, M D

    1985-07-01

    A previously unreported method to relieve excessive plantargrade pressure which may create an intractable plantar keratoma associated with metatarsal head pain is presented. This method is referred to as an intramedullary metatarsal decompression with condylectomy and is performed through a dorsal minimum incision. The rotary action of the bur is demonstrated. This method has proved less traumatic than previous procedures, permitting immediate ambulation with little postoperative pain or edema. In a series of cases, I have compared this method with control studies on the same patient in which intramedullary metatarsal decompression was performed on one foot and a neck osteotomy on the opposite foot. Results with intramedullary metatarsal decompression have been comparable but have fewer postoperative sequelae. Exuberant bone callus formation dorsally and at the osteotomy site, lateral displacement of bone segments, frequency of transfer lesions, delayed healing or nonunion of the osteotomy site, and the possibility of synostosis when two adjacent bones were osteotomized are all decreased. A short review of the rationale, selection of cases, and criteria for orthotics is presented. The concept and simplified method of treatment applied in a series of cases is described. PMID:4028490

  14. Decompressive surgery in the treatment of traumatic brain injury.

    PubMed

    Piek, Jürgen

    2002-04-01

    According to European Brain Injury Consortium (EBIC) and American Brain Injury Consortium (ABIC) guidelines for severe head injuries, decompressive craniectomy is one therapeutic option for brain edema that does not respond to conventional therapeutic measures. As a result of the failure of all recently developed drugs to improve outcome in this patient group, decompressive craniectomy has experienced a revival during the last decade. Although class I studies of this subject are still lacking, there is strong evidence from prospective, uncontrolled trials that such an operation improves outcome in general and also has beneficial effects on various physiologic parameters that are known to be independent predictors for poor outcome. Whether this operation should be performed in a protocol-driven or in a prophylactic manner remains unclear. Decompressive craniectomy may, however, be the only method available in developing countries with limited ICU and monitoring resources. Prospectively controlled and randomized studies to definitively evaluate the effect of this old neurosurgical method on outcome in patients with traumatic brain injury (TBI) are forthcoming.

  15. Interspinous Process Decompression: Expanding Treatment Options for Lumbar Spinal Stenosis

    PubMed Central

    Nunley, Pierce D.; Shamie, A. Nick; Blumenthal, Scott L.; Orndorff, Douglas; Geisler, Fred H.

    2016-01-01

    Interspinous process decompression is a minimally invasive implantation procedure employing a stand-alone interspinous spacer that functions as an extension blocker to prevent compression of neural elements without direct surgical removal of tissue adjacent to the nerves. The Superion® spacer is the only FDA approved stand-alone device available in the US. It is also the only spacer approved by the CMS to be implanted in an ambulatory surgery center. We computed the within-group effect sizes from the Superion IDE trial and compared them to results extrapolated from two randomized trials of decompressive laminectomy. For the ODI, effect sizes were all very large (>1.0) for Superion and laminectomy at 2, 3, and 4 years. For ZCQ, the 2-year Superion symptom severity (1.26) and physical function (1.29) domains were very large; laminectomy effect sizes were very large (1.07) for symptom severity and large for physical function (0.80). Current projections indicate a marked increase in the number of patients with spinal stenosis. Consequently, there remains a keen interest in minimally invasive treatment options that delay or obviate the need for invasive surgical procedures, such as decompressive laminectomy or fusion. Stand-alone interspinous spacers may fill a currently unmet treatment gap in the continuum of care and help to reduce the burden of this chronic degenerative condition on the health care system.

  16. Influence of repeated daily diving on decompression stress.

    PubMed

    Zanchi, J; Ljubkovic, M; Denoble, P J; Dujic, Z; Ranapurwala, S; Pollock, N W

    2014-06-01

    Acclimatization (an adaptive change in response to repeated environmental exposure) to diving could reduce decompression stress. A decrease in post-dive circulating venous gas emboli (VGE or bubbles) would represent positive acclimatization. The purpose of this study was to determine whether four days of daily diving alter post-dive bubble grades. 16 male divers performed identical no-decompression air dives on 4 consecutive days to 18 meters of sea water for 47 min bottom times. VGE monitoring was performed with transthoracic echocardiography every 20 min for 120 min post-dive. Completion of identical daily dives resulted in progressively decreasing odds (or logit risk) of having relatively higher grade bubbles on consecutive days. The odds on Day 4 were half that of Day 1 (OR 0.50, 95% CI: 0.34, 0.73). The odds ratio for a >III bubble grade on Day 4 was 0.37 (95% CI: 0.20, 0.70) when compared to Day 1. The current study indicates that repetitive daily diving may reduce bubble formation, representing a positive (protective) acclimatization to diving. Further work is required to evaluate the impact of additional days of diving and multiple dive days and to determine if the effect is sufficient to alter the absolute risk of decompression sickness.

  17. 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.

  18. Adjacent level spondylodiscitis after anterior cervical decompression and fusion.

    PubMed

    Basu, Saumyajit; Sreeramalingam, Rathinavelu

    2012-05-01

    Postoperative spondylodiscitis after anterior cervical decompression and fusion (ACDF) is rare, but the same occurring at adjacent levels without disturbing the operated level is very rare. We report a case, with 5 year followup, who underwent ACDF from C5 to C7 for cervical spondylotic myelopathy. He showed neurological improvement after surgery but developed discharging sinus after 2 weeks, which healed with antibiotics. He improved on his preoperative symptoms well for the first 2 months. He started developing progressive neck pain and myelopathy after 3 months and investigations revealed spondylodiscitis at C3 and C4 with erosion, collapse, and kyphosis, without any evidence of implant failure or graft rejection at the operated level. He underwent reexploration and implant removal at the operated level (there was good fusion from C5 to C7) followed by debridement/decompression at C3, C4 along with iliac crest bone grafting and stabilization with plate and screws after maximum correction of kyphosis. The biopsy specimen grew Pseudomonas aeruginosa and appropriate sensitive antibiotics (gentamycin and ciprofloxacin) were given for 6 weeks. He was under regular followup for 5 years his myelopathy resolved completely and he is back to work. Complete decompression of the cord and fusion from C2 to C7 was demonstrable on postoperative imaging studies without any evidence of implant loosening or C1/C2 instability at the last followup. PMID:22719127

  19. 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}.

  20. Estimating Serious Decompression Sickness after Loss of Spacecraft Atmosphere

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael; Abercromby, Andrew F. J.

    2016-01-01

    INTRODUCTION: Pressure suits are worn inside spacecraft to protect crewmembers in the event of contamination or depressurization of the spacecraft cabin. Protection against serious (Type II) decompression sickness (DCS) in the event of an unplanned rapid cabin depressurization depends on providing adequate suit pressure to crewmembers because there is no opportunity for oxygen prebreathe. METHODS: A model was developed using literature reports from 41 altitude chamber tests totaling 3,256 decompressions (1,445 including exercise at altitude) with 282 cases of serious DCS. All data involved prebreathe durations < 30 min followed by = 120 min exposures at 13.8 to 34.5 kPa (2 to 5 psia) in young men. A time-dependent index of decompression stress was calculated for the historical decompressions using an existing Tissue Bubble Dynamics Model. This index, in combination with physical activity level at altitude (resting vs. active), provided significant prediction of serious DCS in the dataset when used in a logistic regression model, which was then used to estimate serious DCS risk for a range of hypothetical suit pressures and decompression scenarios. RESULTS: The probability of one or more cases of serious DCS in a four person crew was estimated as 0.73 assuming initial saturation at 1 atmosphere, no prebreathe, ascent to 24.1 kPa (3.5 psia) in 30 sec, and 120 min of activity at 3.5 psia. The estimated probability reduced to 0.36 and 0.16 for equivalent exposures at 31.0 and 40.0 kPa (4.5 and 5.8 psia), respectively. Extrapolation to exposures longer than 120 min suggest further increases in serous DCS risk. DISCUSSION: The need to operate critical spacecraft functions coupled with delayed access to hyperbaric treatment further increases the risk to crewmember safety if serious DCS symptoms are experienced following cabin depressurization. A suit pressure of 5.8 psia provides significantly greater protection to crewmembers than lower pressure alternatives. Lower

  1. 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

  2. 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

  3. 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

  4. 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

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

    NASA Astrophysics Data System (ADS)

    Nikolaev, V. P.

    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.

  6. Nitrogen partial pressures in man after decompression from simulated scuba dives.

    PubMed

    Radermacher, P; Santak, B; Muth, C M; Wenzel, J; Vogt, L; Hahn, M; Falke, K J

    1990-01-01

    In five subjects arterial and central venous nitrogen partial pressures (PN2) were measured after decompression from a chamber dive following a decompression schedule for scuba diving. The simulated dives consisted of exposure at rest to air at 6 bar for 30 min. corresponding to a depth of 50 m. Afterwards the subjects were decompressed with decompression stops at 2.5, 2.2, 1.9, 1.6 and 1.3 bar with a total decompression time of 73 min. Immediately after decompression and every 40 min. until the 240th min. arterial and central venous blood samples were analyzed for PN2 using a manometric Van Slyke apparatus. Venous PN2 remained elevated until 160 min. after decompression indicating still incomplete nitrogen wash-out at least two hours after decompression had been accomplished. Bubble formation is discussed as a cause for prolonged nitrogen elimination. Our data confirm that nitrogen elimination is prolonged after decompression from simulated dives at rest.

  7. 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.

  8. 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

  9. 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.

  10. [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

  11. [Disability evaluation in decompression sickness treated with hyperbaric therapy].

    PubMed

    Zannini, D; Chiozza, G; Formai, C; Oltracqua, S

    1981-12-30

    The Authors report 41 cases of decompression sickness following air scuba diving observed during the last three years at the Istituto di Medicina del Lavoro of the University of Genoa and discuss about consequent injuries and damages (period of hospitalization, temporary and permanent disability). The Authors say that in 12 cases remain permanent disability with limitation more or less serious of the working capacity. They, at last, emphasize that neurological symptoms are getting better during several months so to be necessary to wait for two years at least before estimating definitively advise.

  12. 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

  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. 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

  15. Decompression Induced Crystallization of Basaltic Andesite Magma: Constraints on the Eruption of Arenal Volcano, Costa Rica.

    NASA Astrophysics Data System (ADS)

    Szramek, L. A.; Gardner, J. E.; Larsen, J. F.

    2004-12-01

    Arenal Volcano is a small stratovolcano located 90 km NW of San Jose, Costa Rica. In 1968 current activity began with a Plinian phase, and has continued to erupt lava flows and pyroclastic flows intermittently since. Samples from the Plinian, pyroclastic flow, strombolian, and effusive phases have been studied texturally. Little variation in crystallinity occurs amongst the different phases. Number density of crystals, both 2D and 3D are 50-70 mm-2 and 30,000-50,000 mm-3 in the Plinian sample, compared to the lesser values in other eruptive types. Characteristic crystal size also increases as explosivity decreases. Two samples, both lava flows collected while warm, overlap with the Plinian sample. This suggests that the variations seen may be a result of cooling history. Plagioclase differs between the Plinian sample, in which they are only tabular in shape, and the other eruptive types, which contain both tabular and equant crystals. To link decompression paths of the Arenal magma to possible pre-eruptive conditions, we have carried out hydrothermal experiments. The experiments were preformed in TZM pressure vessels buffered at a fugacity of Ni-NiO and water saturation. Phase equilibria results in conjunction with mineral compositions and temperature estimates by previous workers from active lava flows and two-pyroxene geothermometry, constrain the likely pre-eruptive conditions for the Arenal magma to 950-1040° C with a water pressure of 50-80 MPa. Samples that started from conditions that bracket our estimated pre-eruptive conditions were decompressed in steps of 5-30 MPa and held for various times at each step until 20 MPa was reached, approximating average decompression rates of 0.25, 0.025, 0.0013 MPa/s. Comparison of textures found in the natural samples to the experimentally produced textures suggest that the Plinian eruption likely was fed by magma ascending at 0.05-1 m/s, whereas the less explosive phases were fed by magma ascending at 0.05 m/s or less.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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...

  3. Neuroimaging of diving-related decompression illness: current knowledge and perspectives.

    PubMed

    Kamtchum Tatuene, J; Pignel, R; Pollak, P; Lovblad, K O; Kleinschmidt, A; Vargas, M I

    2014-01-01

    Diving-related decompression illness is classified into 2 main categories: arterial gas embolism and decompression sickness. The latter is further divided into types 1 and 2, depending on the clinical presentation. MR imaging is currently the most accurate neuroimaging technique available for the detection of brain and spinal cord lesions in neurologic type 2 decompression sickness. Rapid bubble formation in tissues and the bloodstream during ascent is the basic pathophysiologic mechanism in decompression illness. These bubbles can damage the central nervous system through different mechanisms, namely arterial occlusion, venous obstruction, or in situ toxicity. Neuroimaging studies of decompression sickness have reported findings associated with each of these mechanisms: some typical results are summarized and illustrated in this article. We also review the limitations of previous work and make practical methodologic suggestions for future neuroimaging studies.

  4. [Theoretical evaluation of the risk of decompression illness during simulated extravehicular activity].

    PubMed

    Nikolaev, V P

    2008-01-01

    Theoretical analysis of the risk of decompression illness (DI) during extravehicular activity following the Russian and NASA decompression protocols (D-R and D-US, respectively) was performed. In contrast to the tradition approach to decompression stress evaluation by the factor of tissue supersaturation with nitrogen, our probabilistic theory of decompression safety provides a completely reasoned evaluation and comparison of the levels of hazard of these decompression protocols. According to this theory, the function of cumulative DI risk is equal to the sum of functions of cumulative risk of lesion of all body tissues by gas bubbles and their supersaturation by solute gases. Based on modeling of dynamics of these functions, growth of the DI cumulative risk in the course of D-R and D-US follows essentially similar trajectories within the time-frame of up to 330 minutes. However, further extension of D-US but not D-R raises the risk of DI drastically.

  5. [Theoretical evaluation of the risk of decompression illness during simulated extravehicular activity].

    PubMed

    Nikolaev, V P

    2008-01-01

    Theoretical analysis of the risk of decompression illness (DI) during extravehicular activity following the Russian and NASA decompression protocols (D-R and D-US, respectively) was performed. In contrast to the tradition approach to decompression stress evaluation by the factor of tissue supersaturation with nitrogen, our probabilistic theory of decompression safety provides a completely reasoned evaluation and comparison of the levels of hazard of these decompression protocols. According to this theory, the function of cumulative DI risk is equal to the sum of functions of cumulative risk of lesion of all body tissues by gas bubbles and their supersaturation by solute gases. Based on modeling of dynamics of these functions, growth of the DI cumulative risk in the course of D-R and D-US follows essentially similar trajectories within the time-frame of up to 330 minutes. However, further extension of D-US but not D-R raises the risk of DI drastically. PMID:19055008

  6. 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

  7. 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

  8. Evaluation of Degenerative Lumbar Scoliosis After Short Segment Decompression and Fusion

    PubMed Central

    Wang, Naiguo; Wang, Dachuan; Wang, Feng; Tan, Bingyi; Yuan, Zenong

    2015-01-01

    Abstract The objective of this study was to investigate short segment decompression of degenerative lumbar scoliosis (DLS) and the efficiency of fusion treatment. After DLS surgery, the patients were retrospectively reviewed using the VAS (visual analog scale) and ODI (Oswestry Disability Index) to assess clinical outcomes. All patients underwent posterior lumbar decompressive laminectomy, pedicle screw internal fixation, and posterolateral bone graft fusion surgery. Radiographic measurements included the scoliotic Cobb angle, the fused Cobb angle, the anterior intervertebral angle (AIA), the sagittal intervertebral angle (SIA), and lumbar lordosis angle. The relationships between these parameters were examined by bivariate Pearson analysis and linear regression analysis. Preoperatively, the Cobb angle at the scoliotic segment was 15.4°, which decreased to 10.2° immediately following surgery (P < 0.05). The AIA significantly increased by the last follow-up (4.4 ± 3.4) compared with pre- and postoperative values (2.5 ± 2.8 and 2.2 ± 2.4, respectively; P < 0.05). However, the scoliotic Cobb angle and the AIA did not correlate with the VAS or ODI scores. At the final follow-up, no patients had pseudoarthrosis or internal instrumentation-related complications. Short fusion surgical treatment results in limited DLS correction, with correction loss over time. The AIA between the upper adjacent segment and proximal fused vertebra continues to increase postoperatively, which does not exacerbate clinical symptoms, as reflected by the low reoperation rates for repairing degeneration at adjacent levels. PMID:26632679

  9. 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.

  10. Effect of oxygen breathing and perfluorocarbon emulsion treatment on air bubbles in adipose tissue during decompression sickness.

    PubMed

    Randsoe, T; Hyldegaard, O

    2009-12-01

    Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect has been explained by the increased transport capacity of oxygen and inert gases in blood. However, previous reports have shown that extravascular bubbles in lipid tissue of rats suffering from DCS will initially grow during oxygen breathing at normobaric conditions. We hypothesize that the combined effect of normobaric oxygen breathing and intravascular PFC infusion could lead to either enhanced extravascular bubble growth on decompression due to the increased oxygen supply, or that PFC infusion could lead to faster bubble elimination due to the increased solubility and transport capacity in blood for nitrogen causing faster nitrogen tissue desaturation. In anesthetized rats decompressed from a 60-min hyperbaric exposure breathing air at 385 kPa, we visually followed the resolution of micro-air bubbles injected into abdominal adipose tissue while the rats breathed either air, oxygen, or oxygen breathing combined with PFC infusion. All bubble observations were done at 101.3 kPa pressure. During oxygen breathing with or without combined PFC infusion, bubbles disappeared faster compared with air breathing. Combined oxygen breathing and PFC infusion caused faster bubble disappearance compared with oxygen breathing. The combined effect of oxygen breathing and PFC infusion neither prevented nor increased transient bubble growth time, rate, or growth ratio compared with oxygen breathing alone. We conclude that oxygen breathing in combination with PFC infusion causes faster bubble disappearance and does not exacerbate transient bubble growth. PFC infusion may be a valuable adjunct therapy during the first-aid treatment of DCS at normobaric conditions.

  11. 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

  12. 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

  13. Initial table treatment of decompression sickness and arterial gas embolism.

    PubMed

    Bond, J G; Moon, R E; Morris, D L

    1990-08-01

    This descriptive, nonrandomized, multicenter-based study compares the treatment outcomes of two major categories of recompression treatment tables for recreational sport SCUBA divers suffering from decompression sickness and/or arterial gas embolism. Stratified and logistic regression analyses were used to compare the enhanced tables, which use pressures of 165 fsw (feet of salt water) or 60 fsw with extended recompression time, to the regular tables, which use pressures of 60 fsw or less without extended recompression time. A total of 113 cases were treated with enhanced tables, 54 being successes. A total of 214 cases were treated with regular tables, 135 being successes. The final logistic statistical model after adjusting for confounding factors found a significant improvement in successful treatment outcomes for divers treated with tables that use pressures of 60 fsw or less without extended recompression time (OR = 0.47, 95% CI = 0.28-0.78).

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Decompression-induced bubble formation in salmonids: comparison to gas bubble disease.

    PubMed

    Beyer, D L; D'Aoust, B G; Smith, L S

    1976-12-01

    The relationship of gas bubble disease (GBD) in fish to decompression-induced bubble formation was investigated with salmonids. Acute bioassays were used to determine equilibration times for critical effects in fish decompressed from depths to 200 fsw. It was found that equilibration of critical tissues was complete in 60-90 min. Salmonids and air-breathers are sensitive to decompressions at similar levels of supersaturation if elimination of excess gas following decompression is unrestricted. However, if elimination is restricted, bubble formation and growth increase accordingly. Tests with mixtures of He-O2, Ar-O2, N2-O2 (80% inert gas: 20% O2) and pure oxygen demonstrated that gas solubility as well as supersaturation (delta P), pressure ratio (initial pressure: final pressure), and absolute pressure must be considered in setting tolerance limits for any decompression. Gases with higher solubility are more likely to produce bubbles upon decompression. Oxygen, however, does not follow this relationship until higher pressures are reached, probably owing to its function in metabolism and in binding with hemoglobin. Tissue responses observed in both GBD and decompressed fish involved similar pathological effects at acute exposures. The circulatory system was consistently affected by bubbles that occluded vessels and blocked flow through the heart.

  3. Dynamics of gas micronuclei formed on a flat hydrophobic surface, the predecessors of decompression bubbles.

    PubMed

    Arieli, R; Marmur, A

    2013-02-01

    It is a long-standing hypothesis that the bubbles which evolve as a result of decompression have their origin in stable gas micronuclei. In a previous study (Arieli and Marmur, 2011), we used hydrophilic and monolayer-covered hydrophobic smooth silicon wafers to show that nanobubbles formed on a flat hydrophobic surface may be the gas micronuclei responsible for the bubbles that evolve to cause decompression sickness. On decompression, bubbles appeared only on the hydrophobic wafers. The purpose of the present study was to examine the dynamics of bubble evolution. The numbers of bubbles after decompression were greater with increasing hydrophobicity. Bubbles appeared after decompression from 150 kPa, and their density increased with elevation of the exposure pressure (and supersaturation), up to 400 kPa. The normal force of attraction between the hydrophobic surface and the bubble, as determined from the volume of bubbles leaving the surface of the wafer, was 38×10(-5) N and the tangential force was 20×10(-5) N. We discuss the correlation of these results with previous reports of experimental decompression and bubble formation, and suggest to consider appropriate modification of decompression models.

  4. 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.

  5. 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

  6. 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.

  7. [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.

  8. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    PubMed

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at < 30 lux, 18 degrees C, and < 50 dBA. In the experimental sessions, either light (1500 lux), magnetic field (16.7 Hz, 0.2 mT), or infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  9. Traumatic canal stenosis should not be an indication for surgical decompression in thoracolumbar burst fracture.

    PubMed

    Zhao, Xing; Fang, Xiang-Qian; Zhao, Feng-Dong; Fan, Shun-Wu

    2010-12-01

    Thoracolumbar burst fracture (TLBF) is a common type of spinal injuries and frequently causes spinal cord injury. The frequency of neurological deficits in all TLBF can reach up to 50-60%. The typical TLBF images seen on axial computerized tomography are the bone fragment projected into the spinal canal, which always persuade surgeons that the narrowed canal must compress the neural content and therefore is responsible for neurological deficits, with the corollary that surgical decompression of spinal canal is an essential therapeutic strategy for functional recovery. We hypothesize that in TLBF, traumatic canal stenosis is a predictive factor for neurological dysfunction and the surgical decompression is vital to the recovery of neurological function. After a review of the available evidences, we conclude that spinal canal stenosis is poorly correlated with neurological dysfunction in TLBF, and surgical decompression is not vital to the neurological recovery. Therefore, traumatic canal stenosis should not be an isolated indication for surgical decompression in TLBF.

  10. Recurrent inner ear decompression sickness associated with a patent foramen ovale.

    PubMed

    Klingmann, Christoph; Knauth, Michael; Ries, Stefan; Kern, Rolf; Tasman, Abel-Jan

    2002-05-01

    Isolated inner ear injuries occurring during shallow scuba dives are an uncommon manifestation of decompression sickness in recreational divers. We describe a patient who presented with the typical symptoms of inner ear involvement after 2 independent dives within the decompression limits. The diver reported symptoms of unilateral (right-sided) hearing loss, tinnitus, and vertigo after dives to 35 and 50 m. After treatment with hyperbaric oxygen, his symptoms completely resolved. To confirm the hypothesis of inner ear decompression sickness (IEDCS), we examined the patient for a right-to-left shunt by cranial Doppler ultrasound and found a patent foramen ovale. The existence of a patent foramen ovale is suspected to be a risk factor for developing neurological symptoms of decompression sickness. There was no evidence of any other risk factors, so we suggest that the relevant right-to-left shunt in our patient may have been the predisposing factor that caused the inner ear symptoms during his scuba dive.

  11. Multiple sclerosis presenting as neurological decompression sickness in a U.S. navy diver.

    PubMed

    Jan, Moore H; Jankosky, Christopher J

    2003-02-01

    A case of clinically definite multiple sclerosis presenting as neurological decompression sickness is presented. A 23-yr-old U.S. Navy diver experienced onset of hypesthesia of the left upper trunk approximately 19 h after making two SCUBA dives. She did not seek medical attention until 3 wk later, at which time she was diagnosed with possible neurological decompression sickness. She was treated with hyperbaric oxygen, but demonstrated no improvement. Further evaluation led to the diagnosis of multiple sclerosis. This case underscores the potential similarity in neurological presentation between multiple sclerosis and decompression sickness. The differential diagnosis of neurological decompression sickness, particularly in atypical cases, should include multiple sclerosis. The appropriateness of medically clearing multiple sclerosis patients for diving is discussed.

  12. Self-reported long-term effects of diving and decompression illness in recreational scuba divers.

    PubMed

    McQueen, D; Kent, G; Murrison, A

    1994-06-01

    The aim of this study was to examine the long-term effects of neurological decompression illness (NDCI) on recreational divers. Thirty-seven divers who had been treated for neurological decompression illness at least 2 years previously, and a control group of 50 divers with no history of decompression illness, responded to a postal questionnaire. Divers in the accident group reported more symptoms of neurological damage, were more likely to believe that diving had a deleterious effect on their health and were more likely to indicate symptoms of psychiatric morbidity. The quantity of diving in the year preceding the survey was associated with reports of neurological damage in both groups and with symptoms of psychiatric morbidity in the accident group. Although requiring confirmation from a longitudinal study, these results suggest that recreational diving can have negative long-term consequences for health, particularly after decompression illness.

  13. Prevention of decompression sickness during extravehicular activity in space: a review.

    PubMed

    Tokumaru, O

    1997-12-01

    Extended and more frequent extravehicular activity (EVA) is planned in NASA's future space programs. The more EVAs are conducted, the higher the incidence of decompression sickness (DCS) that is anticipated. Since Japan is also promoting the Space Station Freedom project with NASA, DCS during EVA will be an inevitable complication. The author reviewed the pathophysiology of DCS and detailed four possible ways of preventing decompression sickness during EVA in space: (1) higher pressure suit technology; (2) preoxygenation/prebreathing; (3) staged decompression; and (4) habitat or vehicle pressurization. Among these measures, development of zero-prebreathe higher pressure suit technology seems most ideal, but because of economic and technical reasons and in cases of emergency, other methods must also be improved. Unsolved problems like repeated decompression or oxygen toxicity were also listed.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. Identification of professional scuba divers with patent foramen ovale at risk for decompression illness.

    PubMed

    Cartoni, Domenico; De Castro, Stefano; Valente, Giuliana; Costanzo, Corrado; Pelliccia, Antonio; Beni, Sergio; Di Angelantonio, Emanuele; Papetti, Federica; Vitali Serdoz, Laura; Fedele, Francesco

    2004-07-15

    Functional and anatomic characteristics of patent foramen ovale (PFO) were investigated in 66 professional scuba divers (41 with and 25 without decompression illness) using transthoracic and transesophageal echocardiography. PFO with right-to-left shunting at rest is associated with decompression illness, particularly the neurologic type. A wider patency diameter together with a higher membrane mobility are associated with the risk of developing the disease in divers with PFO.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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…

  7. 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

  8. Habitat Options to Protect Against Decompression Sickness on Mars

    NASA Astrophysics Data System (ADS)

    Conkin, J.

    2000-07-01

    Men and women are alive today, although perhaps still in diapers, who will explore the surface of Mars. Two achievable goals to enable this exploration are to use Martian resources, and to provide a safe means for unrestricted access to the surface. A cost-effective approach for Mars exploration is to use the available resources, such as water and atmospheric gases. Nitrogen (N2) and Argon (Ar) in a concentration ratio of 1.68/1.0 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 absolute (psia). The habitat and space suit must be designed as an integrated, complementary, 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. However the risk of decompression sickness (DCS) during the extravehicular activity (EVA) in a 3.75 psia suit after exposure to either of the three habitat conditions may limit unrestricted exploration.

  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. 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.

  12. 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.

  13. Addition of zygomatic arch resection in decompressive craniectomy.

    PubMed

    Martin, Arvind G; Abdullah, Johari Yap; Jaafar, Azlan; Ghani, Abdul Rahman Izaini; Rajion, Zainul A; Abdullah, Jafri Malin

    2015-04-01

    Decompressive craniectomy (DC) is a surgical option in managing uncontrolled raised intracranial pressure refractory to medical therapy. The authors evaluate the addition of zygomatic arch (ZA) resection with standard DC and analyze the resulting increase in brain volume using three-dimensional volumetric CT scans. Measurements of brain expansion dimension morphometrics from CT images were also analyzed. Eighteen patients were selected and underwent DC with ZA resection. The pre- and post-operative CT images were analyzed for volume and dimensional changes. CT images of 29 patients previously operated on at the same center were retrieved from the picture archiving and communication system (PACS) and were similarly studied. The findings obtained from the two groups were compared and analyzed. Analysis from three-dimensional CT volumetric techniques revealed an significant increase of 27.97ml (95% confidence interval [CI]: 39.98-180.36; p=0.048) when compared with standard DC. Brain expansion analysis of maximum hemicraniectomy diameter revealed a mean difference of 0.82cm (95% CI: 0.25-1.38; p=0.006). Analysis of the ratio of maximum hemicraniectomy diameter to maximum anteroposterior diameter gave a mean difference of 0.04 (95% CI: 0.05-0.07; p=0.026). The addition of ZA resection to standard DC may prove valuable in terms of absolute brain volume gain. This technique is comparable to other maneuvers used to provide maximum brain expansion in the immediate post-operative period. PMID:25564264

  14. 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

  15. 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

  16. Renin, aldosterone, electrolyte, and cortisol responses to hypoxic decompression.

    PubMed

    Sutton, J R; Viol, G W; Gray, G W; McFadden, M; Keane, P M

    1977-09-01

    Responses of plasma renin activity, plasma aldosterone, plasma cortisol, and plasma electrolyte concentration and urinary electrolyte and aldosterone excretion were studied in four men during hypoxic decompression to a stimulated altitude of 4,760 m in a pressure chamber. Three of the four subjects developed significant acute mountain sickness. Plasma sodium and potassium concentrations were unchanged. No significant change in plasma renin activity was observed, but values tended to fall. Plasma aldosterone concentration was depressed while plasma cortisol was elevated and diurnal variation lost. Urinary sodium excretion was unchanged, but urinary potassium and aldosterone excretion were decreased. The decrease in plasma and urinary aldosterone and urinary potassium in the absence of change in plasma renin activity or plasma potassium is of uncertain origin. It is unlikely to be due to a decrease in adrenocorticotropin secretion since plasma cortisol rose during the same time. None of the changes could be causally implicated in the development of acute mountain sickness although the increase in plasma cortisol was greatest in the most ill. PMID:914712

  17. [Pre-surgical simulation of microvascular decompression for hemifacial spasm using 3D-models].

    PubMed

    Mashiko, Toshihiro; Yang, Qiang; Kaneko, Naoki; Konno, Takehiko; Yamaguchi, Takashi; Watanabe, Eiju

    2015-01-01

    We have been performing pre-surgical simulations using custom-built patient-specific 3D-models. Here we report the advantageous use of 3D-models for simulating microvascular decompression(MVD)for hemifacial spasms. Seven cases of MVD surgery were performed. Two types of 3D-printers were used to fabricate the 3D-models:one using plaster as the modeling material(Z Printer®450, 3D systems, Rock Hill, SC, USA)and the other using acrylonitrile butadiene styrene(ABS)(UP! Plus 3D printer®, Beijing Tiertime Technology, Beijing). We tested three types of models. Type 1 was a plaster model of the brainstem, cerebellum, facial nerve, and the artery compressing the root exit zone of the facial nerve. Part of the cerebellum was digitally trimmed off to observe "the compressing point" from the same angle as that used during actual surgery. Type 2 was a modified Type 1 in which part of the skull was opened digitally to mimic a craniectomy. Type 3 was a combined model in which the cerebellum and the artery of the Type 2 model were replaced by a soft retractable cerebellum and an elastic artery. The cerebellum was made from polyurethane and cast from a plaster prototype. To fabricate elastic arteries, liquid silicone was painted onto the surface of an ABS artery and the inner ABS model was dissolved away using solvent. In all cases, the 3D-models were very useful. Although each type has advantages, the Type-3 model was judged extremely useful for training junior surgeons in microsurgical approaches.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. Significance of Intracranial Pressure Monitoring after Early Decompressive Craniectomy in Patients with Severe Traumatic Brain Injury

    PubMed Central

    Kim, Deok-ryeong; Yang, Seung-Ho; Sung, Jae-hoon; Lee, Sang-won

    2014-01-01

    Objective Early decompressive craniectomy (DC) has been used as the first stage treatment to prevent secondary injuries in cases of severe traumatic brain injury (TBI). Postoperative management is the major factor that influences outcome. The aim of this study is to investigate the effect of postoperative management, using intracranial pressure (ICP) monitoring and including consecutive DC on the other side, on the two-week mortality in severe TBI patients treated with early DC. Methods Seventy-eight patients with severe TBI [Glasgow Coma Scale (GCS) score <9] underwent early DC were retrospectively investigated. Among 78 patients with early DC, 53 patients were managed by conventional medical treatments and the other, 25 patients were treated under the guidance of ICP monitoring, placed during early DC. In the ICP monitoring group, consecutive DC on the other side were performed on 11 patients due to a high ICP of greater than 30 mm Hg and failure to respond to any other medical treatments. Results The two-week mortality rate was significantly different between two groups [50.9% (27 patients) and 24% (6 patients), respectively, p=0.025]. After adjusting for confounding factors, including sex, low GCS score, and pupillary abnormalities, ICP monitoring was associated with a 78% lower likelihood of 2-week mortality (p=0.021). Conclusion ICP monitoring in conjunction with postoperative treatment, after early DC, is associated with a significantly reduced risk of death. PMID:24570814

  3. Out-of-core Compression and Decompression of Large n-dimensional Scalar Fields

    SciTech Connect

    Ibarria, L; Lindstrom, P; Rossignac, J; Szymczak, A

    2003-02-03

    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.

  4. 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.

  5. 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

  6. Online remote control systems for static and dynamic compression and decompression using diamond anvil cells.

    PubMed

    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.

  7. 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.

  8. 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.

  9. 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.

  10. Arthroscopic subacromial decompression: two- to seven-year follow-up.

    PubMed

    Roye, R P; Grana, W A; Yates, C K

    1995-06-01

    Arthroscopic subacromial decompression (ASD) was performed in 88 patients (90 shoulders) with stage II or early III impingement syndrome of the shoulder unresponsive to nonoperative treatment. The purpose of this retrospective study was to evaluate the follow-up an average of 41 months (range 24 to 82 months) after surgery. We wished to compare results in (1) patients with and without rotator cuff tears, (2) in athletes and nonathletes, and (3) in throwers and nonthrowers. Patients were evaluated by (1) Neer's Criteria for Satisfactory Result, (2) the UCLA Shoulder RAting Scale, (3) the Shoulder and Elbow Surgeons Rating Scale, (4) a detailed questionnaire, and (5) patient satisfaction. In the follow-up group (n = 90), 80% met Neer's criteria for satisfactory result; 94% had satisfactory results by the UCLA Shoulder Scale; 95% had a satisfactory result by the Shoulder and Elbow Society Scale; and 93% of shoulder patients expressed satisfaction at follow-up. There were no statistically significant differences in function between the group without rotator cuff tear (n = 47) and the group with rotator cuff tear (n = 43). Satisfactory results were obtained in 68% of throwing athletes and in 90% of nonthrowing athletes (P < .05) by the Neer Rating, whereas only 50% of competitive baseball and softball pitchers had satisfactory results. Out impression is that ASD is an acceptable alternative to open anterior acromioplasty with comparable results for the treatment of the impingement lesion. There were no differences in result in patients who had a partial rotator cuff tear and those who had no tear.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. 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

  12. [Surgical management of trigeminal neuralgia, hemifacial spasm, paroxysmal tinnitus and nystagmus by neurovascular decompression].

    PubMed

    Isu, T; Abe, H; Nakagawa, Y; Aida, T; Tsuru, M; Ito, T; Murai, H

    1983-11-01

    Trigeminal neuralgia, facial spasm, tinnitus, vertigo, and glossopharyngeal neuralgia are believed to be the symptoms complex of hyperactive dysfunction of the cranial nerve caused by vascular cross compression at the root entry (exit) zone of the appropriate nerve. Posterior cranial fossa approach for the neurovascular decompression was enhanced by Jannetta et al (1975). From their experiences of surgery, they emphasized that these symptoms were relieved by surgery. In this report, we will discuss the etiology of the disease, the neurotological examination, the angiographic findings, the operative findings and results in a series of 10 patients who have undergone neurovascular decompression. The series consisted of 4 cases with trigeminal neuralgia, 5 cases with facial spasm, and 1 case with paroxysmal tinnitus accompanied by facial spasm. The postoperative progress in these all patients was excellent and relieved of the symptoms. There was neither mortality nor any significant complication. We stress that the neurovascular decompression surgery is now well justified as the definite treatment for the trigeminal neuralgia and facial spasm, because the surgery can be performed easily and safely by the neurosurgeons. The indication of the neurovascular decompression for the acoustic nerve and glossopharyngeal nerve is still controversial. In our own case, tinnitus was paroxysmal and complicated with facial spasm, not synchronous with facial spasm, but with nystagmus. This selective synchronism between tinnitus and nystagmus is a particular feature of our clinical instance. This particular clinical experience may provide some highly significant suggestions in considering the applicability of neurovascular decompression to the acoustic nerve. PMID:6671636

  13. 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.

  14. 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

  15. Extreme events in computational turbulence.

    PubMed

    Yeung, P K; Zhai, X M; Sreenivasan, Katepalli R

    2015-10-13

    We have performed direct numerical simulations of homogeneous and isotropic turbulence in a periodic box with 8,192(3) 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

  16. 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

  17. 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

  18. 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

  19. [Surgical treatment of trigeminal neuralgia--neurovascular decompression established by Jannetta].

    PubMed

    Isu, T; Abe, H; Nakagawa, Y; Mitsumori, K; Nakagawa, T; Sakuragi, M; Tsuru, M; Ito, T

    1985-01-01

    The etiology of trigeminal neuralgia has been unknown. However, recently, trigeminal neuralgia is believed to be caused by vascular cross compression at the root entry zone of the trigeminal nerve. Posterior cranial fossa approach for the neurovascular decompression was enhanced by Jannetta et al. They emphasized that the pain was relieved by surgery. In this report, we will discuss the operative findings and results in a series of 8 patients who have undergone neurovascular decompression. The postoperative progress in all of these patients was excellent and relieved of the pain. There was neither mortality nor any significant complication. We stress that the neurovascular decompression surgery is now well justified as the definite treatment for the trigeminal neuralgia. PMID:3988235

  20. Suturing-Free Artificial Dura with Dacron Heart Patch in Decompressive Craniectomy and Cranioplasty.

    PubMed

    Wang, Fei; Xue, Yan; Zhao, Si-Shun; Yang, Ting-Jian; Song, Hao-Qing; Liu, Hong

    2015-12-01

    Dacron heart patch has been used in decompressive craniectomy, performing the function of septa, mainly to prevent extra adhesion of temporal muscle and decompressive meningeal adhesion in the second-stage cranioplasty, so as to make the operation easier. Then, we made the following modification technology: (1) We used artificial suturing-free dura participate directly in the duraplasty. (2) Dacron patch is not in need of trimming the side holes and can directly cover the decompression window. From March 2012 to October 2013, we applied the technology of artificial dura with Dacron heart patch in 23 patients; after operation, we found that the initial depressive craniectomy cost less time, due to the tension-reduced suture which was not needed, and in the second-stage cranioplasty, the temporal was easy to remove and had no adhesion with the Dacron patch, so as to reach temporal muscle anatomy preservation, and with no obvious postoperative complication. PMID:27011500

  1. 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.

  2. Weber's syndrome and sixth nerve palsy secondary to decompression illness: a case report.

    PubMed

    Padilla, W; Newton, H B; Barbosa, S

    2005-01-01

    We describe the first case of Weber's Syndrome to present as a manifestation of decompression illness in a recreational scuba diver. Weber's Syndrome is characterized by the presence of an oculomotor nerve palsy and contralateral hemiparesis. The patient was a 55 year-old male with a past medical history of a pulmonary cyst, in whom symptoms developed after a multilevel drift dive to a depth of 89 feet for 53 minutes, exceeding no-decompression limits. Symptom onset was within 30 minutes of surfacing and included the Weber's Syndrome, a sixth nerve palsy, dizziness, nausea, sensory loss, and ataxia. The patient received four U.S. Navy Treatment Tables with complete resolution of all neurological signs and symptoms. The mechanism of injury remains unclear, but may involve aspects of both air gas embolism and decompression sickness. Individuals with pre-existing pulmonary cysts may be at increased risk for dive-related complications.

  3. Endoscopic Sciatic Nerve Decompression in the Prone Position-An Ischial-Based Approach.

    PubMed

    Jackson, Timothy J

    2016-06-01

    Deep gluteal syndrome is described as sciatic nerve entrapment in the region deep to the gluteus maximus muscle. The entrapment can occur from the piriformis muscle, fibrous bands, blood vessels, and hamstrings. Good clinical outcomes have been shown in patients treated by open and endoscopic means. Sciatic nerve decompression with or without piriformis release provides a surgical solution to a difficult diagnostic and therapeutic problem. Previous techniques have used open methods that can now performed endoscopically. The technique of an endoscopic approach to sciatic nerve decompression in the prone position is described as well as its advantages and common findings. Through this ischial-based approach, a familiar anatomy is seen and areas of sciatic nerve entrapment can be readily identified and safely decompressed. PMID:27656390

  4. Aseptic necrosis in compressed air tunnel workers using current OSHA decompression schedules.

    PubMed

    Kindwall, E P; Nellen, J R; Spiegelhoff, D R

    1982-10-01

    Aseptic necrosis (dysbaric osteonecrosis) was discovered in two compressed air tunnel workers who had used the present Occupational Health and Safety Administration (OSHA) decompression tables for compressed air tunneling at pressures greater than 36 pounds per square inch gauge (psig). A roentgenographic study was made of 21 men who had worked at pressures up to 43 psig using the OSHA schedules. Bone scanning was also included. Seven of the men (33%) were found to have aseptic necrosis involving the shoulders, hips or distal femoral shafts and proximal tibia. It became evident that the present OSHA schedules caused not only an unacceptable incidence of decompression sickness but also aseptic necrosis at pressures over 36 psig. New interim tables that are more conservative and that use either air or oxygen as a breathing gas during decompression are undergoing laboratory and worksite evaluation.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Infection with bacteroides thetaiotaomicron during posterior decompression and dynamic stabilization of the lumbar spine: a case report and review of the literature.

    PubMed

    Agarwal, Nitin; Hansberry, David R; Goldstein, Ira M

    2014-08-01

    Patient and surgical risk factors have often been implicated for postoperative posterior spinal wound infection. A 56-year-old male with widely disseminated multiple myeloma presented with severe back pain and lower extremity weakness as a result of fracture and collapse of the L4 vertebral body. Posterior decompression involving bilateral pedicle resection and partial L4 corpectomy was performed. Stabilization was performed by Dynesys instrumentation of L3-5, screw supplementation with polymethylmethacrylate, and posterolateral fusion was performed. Postoperatively, the patient suffered from multiple infections, including Bacteroides thetaiotaomicron, which were eventually resolved with antibiotic as well as incision and debridement treatment regimens. In cases with numerous perioperative risk factors for infections, the best therapeutic approach may be a preventative one. An understanding of the relevant risk factors may enable the physician to facilitate a perioperative condition best suited for optimal treatment. A case report of infection with Bacteroides thetaiotaomicron during lumbar decompression and dynamic stabilization as well as a review of the literature regarding infection risk factors are presented.

  10. 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.

  11. 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.

  12. 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.

  13. [Penetrating brain injury due to a large asbestos fragment treated by decompressive craniectomy: case report].

    PubMed

    Andrade, Gustavo Cardoso de; Silveira, Roberto Leal; Arantes, Aluízio Augusto; Fonseca Filho, Gilberto Almeida; Pinheiro, Nilson

    2004-12-01

    We report the case of a 22-year-old man victim of penetrating brain injury due to a 15 x 12 asbestos fragment and a successfully treatment via decompressive craniectomy. Unlike gunshot wounds to the head, penetrating brain injury from low energy objects are unusual. Most cases reported involve cranio-orbitary injuries as well as self inflicted lesions in mentally ill patients. The reported case is noteworthy due to the large dimensions of the foreign body, the treatment via decompressive craniectomy and the good patient functional outcome.

  14. Nephroureteral Obstructions: The Use of Stents and Ureteral Bypass Systems for Renal Decompression.

    PubMed

    Palm, Carrie A; Culp, William T N

    2016-11-01

    Canine and feline nephroureteral obstruction is a complex disease process that can be challenging to treat. Although the availability of various imaging modalities allows for a straightforward diagnosis to be made in most cases, the decision-making process for when a case should be taken to surgery and the optimal treatment modality that should be used for renal decompression remains controversial. In the following discussion, an overview of the perioperative management of cases with nephroureterolithiasis and nephroureteral obstruction is reviewed, with particular focus on the use of renal decompressive procedures, such as ureteral stenting and subcutaneous ureteral bypass system placement. PMID:27497503

  15. Neurologic presentation of decompression sickness and air embolism in sport divers.

    PubMed

    Dick, A P; Massey, E W

    1985-05-01

    In a retrospective study of scuba divers with neurologic injuries, we found that mild symptoms were common. Seventy divers had decompression sickness, most often with paresthesias or numbness, rarely with paresis. Thirty-nine divers had air embolism that often caused unconsciousness or mild symptoms of cerebral injury. Many divers with neurologic decompression sickness gave histories of dives that were within conventional limits, and many with air embolism gave no history of breath-holding during ascent. Mild symptoms sometimes regressed spontaneously. Recompression delays were responsible for poor responses to therapy.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. [Lower extremity amputation rates in diabetic patients].

    PubMed

    Cisneros-González, Nelly; Ascencio-Montiel, Iván Jesús; Libreros-Bango, Vita Norma; Rodríguez-Vázquez, Héctor; Campos-Hernández, Ángel; Dávila-Torres, Javier; Kumate-Rodríguez, Jesús; Borja-Aburto, Víctor Hugo

    2016-01-01

    Introducción: las amputaciones de extremidades inferiores disminuyen la calidad de vida de los pacientes con diabetes mellitus (DM). El objetivo de este estudio fue describir el índice de amputaciones de extremidades inferiores (mayores y menores) en sujetos con DM adscritos al Instituto Mexicano del Seguro Social (IMSS), comparando los años 2004 y 2013. Métodos: estudio observacional transversal comparativo. Se evaluaron los registros hospitalarios de amputaciones obtenidos del Sistema de Estadísticas Médicas (DataMart) y del Censo de pacientes con DM obtenido del Sistema de Atención Integral a la Salud. Se calcularon los índices de amputaciones mayores y menores x 100,000 sujetos con DM adscritos a Medicina Familiar. Resultados: durante 2004 y 2013 se observaron 2 334 340 y 3 416 643 pacientes con DM adscritos a Medicina Familiar respectivamente. Los promedios de edad al momento de la amputación fueron similares en el año 2004 y 2013 (61.7 años para las amputaciones menores y 65.6 años para las amputaciones mayores). Los índices de amputaciones mayores fueron de 100.9 y de 111.1 x 100 000 sujetos con DM en 2004 y 2013; mientras que el índice de amputaciones menores de extremidades inferiores fue de 168.8 y de 162.5 x 100 000 sujetos con DM en el durante 2004 y 2013 respectivamente. Conclusiones: el índice de amputaciones de extremidades inferiores en el IMSS es muy alto comparado con lo reportado en países desarrollados. El índice de amputaciones mayores se incrementó para el año 2013, comparado con 2004.

  1. 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

  2. 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

  3. Pharmacological versus microvascular decompression approaches for the treatment of trigeminal neuralgia: clinical outcomes and direct costs

    PubMed Central

    Lemos, Laurinda; Alegria, Carlos; Oliveira, Joana; Machado, Ana; Oliveira, Pedro; Almeida, Armando

    2011-01-01

    In idiopathic trigeminal neuralgia (TN) the neuroimaging evaluation is usually normal, but in some cases a vascular compression of trigeminal nerve root is present. Although the latter condition may be referred to surgery, drug therapy is usually the first approach to control pain. This study compared the clinical outcome and direct costs of (1) a traditional treatment (carbamazepine [CBZ] in monotherapy [CBZ protocol]), (2) the association of gabapentin (GBP) and analgesic block of trigger-points with ropivacaine (ROP) (GBP+ROP protocol), and (3) a common TN surgery, microvascular decompression of the trigeminal nerve (MVD protocol). Sixty-two TN patients were randomly treated during 4 weeks (CBZ [n = 23] and GBP+ROP [n = 17] protocols) from cases of idiopathic TN, or selected for MVD surgery (n = 22) due to intractable pain. Direct medical cost estimates were determined by the price of drugs in 2008 and the hospital costs. Pain was evaluated using the Numerical Rating Scale (NRS) and number of pain crises; the Hospital Anxiety and Depression Scale, Sickness Impact Profile, and satisfaction with treatment and hospital team were evaluated. Assessments were performed at day 0 and 6 months after the beginning of treatment. All protocols showed a clinical improvement of pain control at month 6. The GBP+ROP protocol was the least expensive treatment, whereas surgery was the most expensive. With time, however, GBP+ROP tended to be the most and MVD the least expensive. No sequelae resulted in any patient after drug therapies, while after MDV surgery several patients showed important side effects. Data reinforce that, (1) TN patients should be carefully evaluated before choosing therapy for pain control, (2) different pharmacological approaches are available to initiate pain control at low costs, and (3) criteria for surgical interventions should be clearly defined due to important side effects, with the initial higher costs being strongly reduced with time. PMID:21941455

  4. 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.

  5. 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.

  6. Comparison of Functional Outcomes following Surgical Decompression and Posterolateral Instrumented Fusion in Single Level Low Grade Lumbar Degenerative versus Isthmic Spondylolisthesis

    PubMed Central

    Hasankhani, Ebrahim Ghayem; Rahimi, Mohammad Dawood; Khanzadeh, Reza

    2014-01-01

    Background The two most common types of surgically treated lumbar spondylolisthesis in adults include the degenerative and isthmic types. The aim of this study was to compare the functional outcomes of surgical decompression and posterolateral instrumented fusion in patients with lumbar degenerative and isthmic spondylolisthesis. Methods In this retrospective study, we reviewed the clinical outcomes in surgically treated patients with single level, low grade lumbar degenerative, and isthmic spondylolisthesis (groups A and B, respectively) from August 2007 to April 2011. We tried to compare paired settings with similar initial conditions. Group A included 52 patients with a mean age of 49.2 ± 6.1 years, and group B included 52 patients with a mean age of 47.3 ± 7.4 years. Minimum follow-up was 24 months. The surgical procedure comprised neural decompression and posterolateral instrumented fusion. Pain and disability were assessed by a visual analog scale (VAS) and the Oswestry Disability Index (ODI), respectively. The Wilcoxon and Mann-Whitney U-tests were used to compare indices. Results The most common sites for degenerative and isthmic spondylolisthesis were at the L4-L5 (88.5%) and L5-S1 (84.6%) levels, respectively. Surgery in both groups significantly improved VAS and ODI scores. The efficacy of surgery based on subjective satisfaction rate and pain and disability improvement was similar in the degenerative and isthmic groups. Notable complications were also comparable in both groups. Conclusions Neural decompression and posterolateral instrumented fusion significantly improved pain and disability in patients with degenerative and isthmic spondylolisthesis. The efficacy of surgery for overall subjective satisfaction rate and pain and disability improvement was similar in both groups. PMID:24900900

  7. Outcome of carpal tunnel decompression: the influence of age, gender, and occupation

    PubMed Central

    Majid, I.; Clarke, M.; Kershaw, C. J.

    2008-01-01

    The aim of this study was to investigate the effect of age, gender, and occupation on the outcome of carpal tunnel decompression. A total of 479 patients (342 females, 137 males) with a mean age of 56 years undergoing 608 carpal tunnel decompressions were prospectively studied. Outcome was assessed using the Brigham Hospital carpal tunnel questionnaire at two weeks pre-operatively and six months post-operatively. Cases were divided into four age categories (less than 40 years of age, 40–59, 60–79, and over 80 years of age) and two occupation (repetitive and non-repetitive) groups. The mean differences for both the symptom-severity and functional-status scores amongst the four age categories were similar and no significant difference was found. The mean differences for both the symptom-severity and functional-status scores between females and males and the two occupation groups were similar and no significant differences were found. The majority of the patient’s symptoms improved following carpal tunnel decompression. However, we found no influence of age, gender, or occupation on the outcome of carpal tunnel decompression in our series of patients. PMID:18923831

  8. Application of COMPONT Medical Adhesive Glue for Tension-Reduced Duraplasty in Decompressive Craniotomy

    PubMed Central

    Zhou, Yujia; Wang, Gesheng; Liu, Jialin; Du, Yong; Wang, Lei; Wang, Xiaoyong

    2016-01-01

    Background The aim of this study was to evaluate the application of medical adhesive glue for tension-reduced duraplasty in decompressive craniotomy. Material/Methods A total of 56 cases were enrolled for this study from Jan 2013 to May 2015. All patients underwent decompressive craniotomy and the dura was repaired in all of them with tension-reduced duraplasty using the COMPONT medical adhesive to glue artificial dura together. The postoperative complications and the healing of dura mater were observed and recorded. Results No wound infection, epidural or subdural hematoma, cerebrospinal fluid leakage, or other complications associated with the procedure occurred, and there were no allergic reactions to the COMPONT medical adhesive glue. The second-phase surgery of cranioplasty was performed at 3 to 6 months after the decompressive craniotomy in 32 out of the 56 cases. During the cranioplasty we observed no adherence of the artificial dura mater patch to the skin flap, no residual COMPONT glue, or hydropic or contracture change of tissue at the surgical sites. Additionally, no defect or weakening of the adherence between the artificial dura mater patch and the self dura matter occurred. Conclusions COMPONT medical adhesive glue is a safe and reliable tool for tension-reduced duraplasty in decompressive craniotomy. PMID:27752035

  9. Emergent Decompressive Craniectomy in Patients with Fixed DilatedPupils; A Single Center Experience

    PubMed Central

    Moscote-Salazar, Luis Rafael; Alvis-Miranda, Hernando Raphael; Palencia, Camilo; M. Rubiano, Andres

    2013-01-01

    This is a case series which report the clinical results of decompressive craniectomy in 4 patients with dilated pupils secondary to traumatic brain injury and postoperative edema. Between 2011 and 2012, four patients, 3 males and 1 female, aged between 35 and 64 with mean age of 50.1±8.9 years, underwent decompressive craniectomy due to brain traumatic edema. The follow up period ranged between 1 to 6 months. All patients had Glasgow coma score (GCS) of 3-4 at admission, and the duration of pupils being mydriatic was less than 20 minutes before the operation. All patients had moderate disability with GCS of 4 after the operation. Decompressive craniectomy can be a life-saving procedure which provides a better outcome in patients with dilated pupils secondary to brain trauma injury and postoperative edema with timing of less than 20 minutes. However, the small number of the patients in this study is the main limitation to the accuracy of the results, and more studies with larger number of patients are warranted to evaluate the efficiency of decompressive craniectomy in patients with dilated pupils. PMID:27162852

  10. The kangaroo rat as a model for type I decompression sickness.

    PubMed

    Hills, B A; Butler, B D

    1978-12-01

    This study involved 720 exposures of 70 kangaroo rats trapped in West Texas and showed that decompression-induced tail biting in this animal provides a good animal model for marginal limb bends in man. That this phenomenon can be reversed by recompression and pathological examination of the tail both indicated that a similar mechanism is probably involved in kangaroo rats and humans. Quantitatively, the most susceptible 20% of kangaroo rats can reproduce the no-stop decompression limits for man for exposure times ranging from 5 min to 8 h, for both air and helium-oxygen. Even the average minimum no-tail-biting depth of 46.2 fsw (2.40 ATA) for this species is much closer to the minimum bends depth of man than to the equivalent depth for other animals of its size, and is as good as the goats'. Its size and habits make the kangaroo rat much more convenient than other animals to use as a model for marginal decompression sickness, and particularly attractive economically for testing long helium-oxygen schedules and other means of decompression sickness prevention.

  11. Multimodal intraoperative monitoring (MIOM) during surgical decompression of thoracic spinal stenosis in 36 patients

    PubMed Central

    Sutter, Martin A.; Grob, Dieter; Porchet, F.; Jeszenszky, Dezsö; Dvorak, Jiri

    2007-01-01

    A prospective study of 36 patients who received multimodal intraoperative monitoring (MIOM) during decompression of thoracic spinal stenosis between March 2000 and December 2005 was chosen as the study design. The objective was to determine the sensitivity and specificity of MIOM techniques used for monitoring spinal cord during surgical thoracic decompression. The background data revealed that the surgical decompression for thoracic spinal stenosis is less frequent than in other regions of the spine. However, due to the relative narrow spinal canal, neurological complications could be severe. The combination of monitoring ascending and descending pathways may provide an early alert to the surgeon in order to alter the surgical procedure, and avoid neurological complications. The methods involved evaluation of intraoperative somatosensory spinal and cerebral evoked potentials and motor evoked potentials of the spinal cord and muscles that were compared with post operative clinical neurological changes. 36 consecutive patients with thoracic spinal stenosis of different aetiologies were monitored by the means of MIOM during the surgical procedure. 31 patients had true negative while one patient had false positive findings. Three patients had true positive and one patient had false negative findings. This indicates a sensitivity of 75% and a specificity of 97%. The one case of false negative findings recovered completely within 3 months. In conclusion, the MIOM is an effective method of monitoring the spinal cord during surgical decompression of the thoracic spine. PMID:17610089

  12. Real-time Monitoring of the Lateral Spread Response Resulting from Serial Decompression for Hemifacial Spasm Caused by a Fusiform Aneurysm.

    PubMed

    Lee, Sung Ho; Choi, Seok Keun; Kim, Johnho

    2015-07-01

    Fusiform aneurysm as a cause of hemifacial spasm (HFS) is an extremely rare condition. A 69-year-old man developed paroxysmal spasm of his left side facial muscles over a period of 5 years. Radiologic images demonstrated a left vertebral artery (VA) fusiform aneurysm compressing the root entry zone of the left facial nerve. The patient underwent serial surgical procedures for the treatment of HFS under intraoperative electromyography monitoring. Lateral spread response (LSR) did not disappear despite 5 minutes of extracranial left VA ligation and remained after cerebrospinal fluid drainage after dura opening. After interposition of the VA through Teflon felt insertion, the LSR finally disappeared. The patient became symptom free immediately after the surgery and continued as such throughout a follow-up period of 1 year. This is the first report involving real-time monitoring of the LSR changes resulting from serial procedures of decompression in an HFS caused by a fusiform aneurysm of the VA.

  13. 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

  14. 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

  15. Volcanic lightning in the lab: observations from rapid decompression experiments with natural volcanic samples

    NASA Astrophysics Data System (ADS)

    Alatorre-Ibarguengoitia, M. A.; Cimarelli, C.; Scheu, B.; Kueppers, U.; Dingwell, D. B.

    2012-12-01

    Explosive volcanic eruptions often produce spectacular volcanic lightning. Recent years have seen volcanic lightning detection used as part of a portfolio of developing techniques to monitor volcanic eruptions. Yet volcanic lightning continues to be poorly understood, because there are still few direct scientific observations of the phenomena. Lightning strikes produced during volcanic eruptions have been associated with two phases with completely different dynamics: 1) In the explosive phase, volcanic particles and gas are violently ejected producing lightning near the vent; 2) in the second phase, lightning discharges occur within the eruption plume produced by the rise of the gas-ash-mixture. Almost all the research on volcanic charging has been carried out on the second phase because the plume covers a wide area and measurements can be made at several km from the vent. Given its explosive nature, direct electric measurements on the first phase are severely restricted. We generate lightning in rapid decompression experiments with natural volcanic particles. These experiments were performed in a shock-tube apparatus that mimics the explosive phase of volcanic eruptions under controlled conditions. Upon decompression (from 5-15 MPa Argon pressure to 0,1 MPa),loose volcanic ash is ejected into a voluminous tank at atmospheric conditions. The ejection of the particles is monitored using a high-speed camera at frame rates of up to 65,000 frames per second. We performed experiments with samples from different volcanoes and with different grain-sizes. In some experiments we observe more than 120 lightning strikes of up to 5 cm in length within less than10 ms. Most of the lightning strikes are observed in only one frame, suggesting that they last less than 20 microseconds. Our observations indicate that particle charging and lightning are strongly controlled by the ejection dynamics and the sample characteristics. A fundamental advantage of the laboratory experiments is

  16. 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

  17. 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

  18. Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation.

    PubMed

    Bond, Aaron E; Jane, John A; Liu, Kenneth C; Oldfield, Edward H

    2015-05-01

    OBJECT The authors completed a prospective, institutional review board-approved study using intraoperative MRI (iMRI) in patients undergoing posterior fossa decompression (PFD) for Chiari I malformation. The purpose of the study was to examine the utility of iMRI in determining when an adequate decompression had been performed. METHODS Patients with symptomatic Chiari I malformations with imaging findings of obstruction of the CSF space at the foramen magnum, with or without syringomyelia, were considered candidates for surgery. All patients underwent complete T1, T2, and cine MRI studies in the supine position preoperatively as a baseline. After the patient was placed prone with the neck flexed in position for surgery, iMRI was performed. The patient then underwent a bone decompression of the foramen magnum and arch of C-1, and the MRI was repeated. If obstruction was still present, then in a stepwise fashion the patient underwent dural splitting, duraplasty, and coagulation of the tonsils, with an iMRI study performed after each step guiding the decision to proceed further. RESULTS Eighteen patients underwent PFD for Chiari I malformations between November 2011 and February 2013; 15 prone preincision iMRIs were performed. Fourteen of these patients (93%) demonstrated significant improvement of CSF flow through the foramen magnum dorsal to the tonsils with positioning only. This improvement was so notable that changes in CSF flow as a result of the bone decompression were difficult to discern. CONCLUSIONS The authors observed significant CSF flow changes when simply positioning the patient for surgery. These results put into question intraoperative flow assessments that suggest adequate decompression by PFD, whether by iMRI or intraoperative ultrasound. The use of intraoperative imaging during PFD for Chiari I malformation, whether by ultrasound or iMRI, is limited by CSF flow dynamics across the foramen magnum that change significantly when the patient is

  19. Australian scuba diving fatalities and decompression sickness: erratum and further analysis.

    PubMed

    Lippmann, John

    2009-03-01

    Dear Editor, I am writing to clarify some points made in my recent article on Australian scuba diving fatalities and decompression sickness in Diving and Hyperbaric Medicine.¹ First, I wish to point out a publishing error in Table 4. The rate for DAN America Members was 11-18 deaths per 100,000 Members and not per 100,000 dives as shown in Table 4. A corrected version of these data is shown in Table 1. When assessing the risk of death of divers in Australia, I used the combined results of two different survey modes, one for Australian residents and the other for overseas visitors, to yield a total number of dives for Australia. Although this was the only way I could see of trying to roughly estimate a general rate for Australia, I am aware, and should have stated in the Discussion, that this method can sometimes provide unreliable results due to the different methods of data collection. A more reliable result, albeit not a general rate, can be achieved by calculating the incident rate separately for residents and visitors rather than combining them. This would have given estimates of 0.7 deaths per 100,000 dives for residents (95% CI 0.3, 1.5) and 0.4 per 100,000 dives for visitors (95% CI 0.1, 1.2), rather than the combined 0.57 per 100,000 dives reported. As pointed out to me by some colleagues at DAN America, given that some of the visitors may have dived elsewhere during the period and died in a dive accident outside Australia, it would have been more appropriate, when reporting a per person rate, not to combine visitors with Australian divers and to use deaths per visitor rather than deaths per diver for the international data. The same observation applies to the data previously reported from Stoney Cove, where the authors reported a rate per diver rather than a rate per visitor.² In this case, the estimates would better have been reported as 8.5 per 100,000 resident divers (95% CI 4.2, 17.5) and 1.5 per 100,000 visitors (95% CI 0.5, 4.3). Where I separately

  20. 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.

  1. Minimally invasive surgery in adult degenerative scoliosis: a systematic review and meta-analysis of decompression, anterior/lateral and posterior lumbar approaches

    PubMed Central

    Huo, Ya Ruth; Hogan, Jarred A.; Xu, Joshua; Dunn, Alexander; Cho, Samuel K.; Mobbs, Ralph J.; McKenna, Patrick; Rajagopal, Trichy; Altaf, Farhaan

    2016-01-01

    Background Minimally invasive approaches for the treatment of adult degenerative scoliosis have been increasingly implemented. However, little data exists regarding the safety and complication profiles of minimally invasive lumbar interbody fusion (LIF) for adult degenerative scoliosis. This study aimed to greater understand different minimally invasive surgical approaches for adult degenerative scoliosis with respect to clinical outcomes, changes in radiographic measurements, and complication profiles via meta-analytical techniques. Methods A systematic search of six databases from inception to September 2015 was performed by two independent reviewers. Relevant studies were those that described the safety and/or effectiveness of minimally invasive anterior or lateral LIF (LLIF), transforaminal LIF (TLIF), and decompression only. Meta-analytical techniques and meta-regression were used to pool overall rates, and compare the different techniques. There was no financial funding or conflict of interest. Results A total of 29 studies (1,228 patients) were included in this meta-analysis. Total pooled fusion rate was 95.9% (95% CI: 92.7–98.2%) for the anterior/lateral approach. The pooled construct or hardware-related complications was 4.3%, and was similar among anterior/lateral (4.4%) and posterior (5.2%) techniques. The total pooled pseudoarthrosis rate was 4.3% for the lateral approach. The overall pooled rate of motor deficit was 2.7% (95% CI: 1.7–4.0%). Subgroup meta-regression demonstrated that the anterior/lateral approach had the highest rate of motor deficits (3.6% LLIF vs. 0.7% TLIF vs. 0.5% decompression, P=0.004). The overall pooled rate of sensory deficit was 2.4%, highest for the anterior/lateral technique (3.3%) compared to TLIF (0.7%) and decompression (0.5%). The infection rate, dural tears/CSF leak, cardiac and pulmonary events were similar among the techniques, with a pooled value of 2.6%, 3.9%, 1.7%, and 1.4%, respectively. Similarly satisfactory

  2. Minimally invasive surgery in adult degenerative scoliosis: a systematic review and meta-analysis of decompression, anterior/lateral and posterior lumbar approaches

    PubMed Central

    Huo, Ya Ruth; Hogan, Jarred A.; Xu, Joshua; Dunn, Alexander; Cho, Samuel K.; Mobbs, Ralph J.; McKenna, Patrick; Rajagopal, Trichy; Altaf, Farhaan

    2016-01-01

    Background Minimally invasive approaches for the treatment of adult degenerative scoliosis have been increasingly implemented. However, little data exists regarding the safety and complication profiles of minimally invasive lumbar interbody fusion (LIF) for adult degenerative scoliosis. This study aimed to greater understand different minimally invasive surgical approaches for adult degenerative scoliosis with respect to clinical outcomes, changes in radiographic measurements, and complication profiles via meta-analytical techniques. Methods A systematic search of six databases from inception to September 2015 was performed by two independent reviewers. Relevant studies were those that described the safety and/or effectiveness of minimally invasive anterior or lateral LIF (LLIF), transforaminal LIF (TLIF), and decompression only. Meta-analytical techniques and meta-regression were used to pool overall rates, and compare the different techniques. There was no financial funding or conflict of interest. Results A total of 29 studies (1,228 patients) were included in this meta-analysis. Total pooled fusion rate was 95.9% (95% CI: 92.7–98.2%) for the anterior/lateral approach. The pooled construct or hardware-related complications was 4.3%, and was similar among anterior/lateral (4.4%) and posterior (5.2%) techniques. The total pooled pseudoarthrosis rate was 4.3% for the lateral approach. The overall pooled rate of motor deficit was 2.7% (95% CI: 1.7–4.0%). Subgroup meta-regression demonstrated that the anterior/lateral approach had the highest rate of motor deficits (3.6% LLIF vs. 0.7% TLIF vs. 0.5% decompression, P=0.004). The overall pooled rate of sensory deficit was 2.4%, highest for the anterior/lateral technique (3.3%) compared to TLIF (0.7%) and decompression (0.5%). The infection rate, dural tears/CSF leak, cardiac and pulmonary events were similar among the techniques, with a pooled value of 2.6%, 3.9%, 1.7%, and 1.4%, respectively. Similarly satisfactory

  3. The clinical study of percutaneous disc decompression of treating herniation of cervical disc with Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Zhang, Dianxue; Cheng, Hefu; Wang, Jindong

    2005-07-01

    Objective: The possibility of PLDD (percutaneous laser disc decompression) and an ideal non-operative method which is long everlasting effect for PLDD was investigated. Methods: 159 patients of Cervical Disc Herniation with PLDD were studied. All the herniated discs were irradiated with 10­15J/S Nd:YAG laser quantum through optical-fiber under the supervision of C-arm X-ray. Results: All the patients were followed and reexamined CT or MRI after one to six months of PLDD. The result of cured (67.92%), excellent (24.53%), moderation (5.66%), non-effect (1.88%) was got. The excellent rate was 88.24%. The effective rate was 97.65%. Non-effective rate was 2.35%. Conclusion: When irradiated with Nd:YAG laser, the nucleus pulposus was vapouring, charring and coagulating. The volume and inner-pressure of the disc decreased. So the symptoms and signs improved. The main value of this methods were micro-damage, non-operation, no bleeding, no bone injury, good therapy effect, quick recovery, lesser pain, safety and excellent long everlasting effect. It is an ideal non-operative method of treating PLDD.

  4. Early pressure dressing for the prevention of subdural effusion secondary to decompressive craniectomy in patients with severe traumatic brain injury.

    PubMed

    Xu, Gang-Zhu; Li, Wen; Liu, Kai-Ge; Wu, Wei; Lu, Wen-Chao; Zhang, Jun-Feng; Wang, Mao-De

    2014-09-01

    This study was performed to investigate the effect of early pressure dressing on the prevention of postoperative subdural effusion secondary to decompressive craniectomy (DC) in patients with severe traumatic brain injury (STBI). Patients with STBI who had undergone DC for refractory increased intracranial pressure between January 2008 and December 2011 (n = 169) were randomly divided into early pressure dressing (n = 82) and control (n = 87) groups. Early pressure dressing with an elastic bandage or general wrapping (control treatment) was applied 7 to 10 days after DC. Patients' age, sex, preoperative Glasgow Coma Scale score, incidence rate of subdural effusion, hospitalization time, and postoperative Glasgow Outcome Scale score were compared between groups. Intracranial pressure was measured immediately before and on the day after pressure dressing. No significant difference in age, sex, preoperative Glasgow Coma Scale score, or postoperative Glasgow Outcome Scale score was observed between groups (P > 0.05). Subdural effusion incidence rates were significantly lower in the early pressure dressing group than those in the control group (χ² = 5.449, P = 0.021), and a larger proportion of patients in the early pressure dressing group was hospitalized for 30 days or less (χ² = 5.245, P = 0.027). Early pressure dressing 7 to 10 days after DC, which is a noninvasive, simple procedure, reduced the incidence rate of subdural effusion and shortened hospitalization time after DC for STBI.

  5. Ex vivo human platelet aggregation induced by decompression during reduced barometric pressure, hydrostatic, and hydrodynamic (Bernoulli) effect.

    PubMed

    Murayama, M

    1984-03-01

    Decompression of human platelet-rich plasma (PRP) in siliconized glass or plastic to 380 mm Hg for 3 hours at 38 degrees C produced platelet aggregation independent of pO2. Aggregation also took place when PRP was compressed to 8,000 PSI and then decompressed slowly to one atmosphere (14.7 PSI) without gas bubble formation. Platelets also aggregated when plasma was decompressed hydrodynamically (Bernoulli effect) at room temperature. It was also found that the drugs piracetam (2-oxypyrolidine acetamide) and pentoxifylline (1-(5-oxohexyl)-theobromine) at 0.5 and 1.0 mM prevent thrombocyte aggregation. Implications for mountain sickness are discussed.

  6. Temperature effects in supercritical fluid chromatography: a trade-off between viscous heating and decompression cooling.

    PubMed

    De Pauw, Ruben; Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2014-10-24

    The study of radial and axial temperature profiles always has been an area interest both in liquid chromatography (LC) and supercritical fluid chromatography (SFC). Whereas in LC always an increase in temperature is observed due to the dominance of viscous heating, in SFC, especially for low modifier content, a decrease in temperature is found due to the much larger decompression cooling. However, for higher modifier content and higher operating pressure, the temperature effects become a trade-off between viscous heating and decompression cooling, since in SFC the latter is a strong function of operating pressure and mobile phase composition. At a temperature of 40°C and for neat CO2, the effect of decompression cooling and viscous heating cancel each other out at a pressure 450bar. This pressure decreases almost linearly with volume fraction of methanol to 150bar at 25vol%. As a result, both cooling and heating effects can be observed when operating at high back pressure, large column pressure drops or high modifier content. For example at a back pressure of 150bar and a column pressure drop of 270bar decompression cooling is observed throughout the column. However at 300bar back pressure and the same pressure drop, the mobile phase heats up in the first part of the column due to viscous heating and then cools in the second part due to decompression cooling. When coupling columns (2.1mm×150mm, 1.8μm fully porous particles) at very high operating pressure (e.g. 750bar for 8vol%), the situation is even more complex. E.g. at a back pressure of 150bar and using 8vol% methanol, viscous heating is only observed in the first column whereas only decompression cooling in the second. Further increasing the inlet pressure up to 1050bar resulted in no excessive temperature differences along the column. This implies that the inlet pressure of SFC instrumentation could be expanded above 600bar without additional band broadening caused by excessive radial temperature

  7. The effect of breathing hyperoxic gas during simulated submarine escape on venous gas emboli and decompression illness.

    PubMed

    Blogg, S L; Gennser, M; Loveman, G A M; Seddon, F M; Thacker, J C; White, M G

    2003-01-01

    Raised internal pressure in a distressed submarine rapidly increases the risk of decompression sickness (DCS) following submarine escape. The hypothesis that breathing a hyperoxic gas during escape may reduce the risk of DCS was tested using goats. Shallow air saturation and simulated submarine escape dives were carried out either singularly or in combination (saturation, escape, or saturation followed by escape) using air or 60% / 40% oxygen (O2) / nitrogen (N2) mixture as breathing gas during the escapes. Post-surfacing, animals were observed for signs of DCI and O2 toxicity. Precordial Doppler ultrasound was used to score venous gas emboli (VGE) using the Kisman Masurel (KM) scale. Following escape from 2.5 MPa, the rate at which VGE disappeared in the hyperoxic group (n = 8) was significantly faster(p < 0.05) than the air group (n = 7). One case of pulmonary barotrauma with arterial gas embolism occurred in the air group, but no cases of DCS were observed. After saturation at 0.18 MPa followed by escape from 2.5 MPa, DCS occurred in four of 15 animals in the air group and in two of 16 animals in the hyperoxic group. The rate of disappearance of VGE was significantly faster (p < 0.01) in the hyperoxic group. O2 toxicity was not discernible in any of the animals. PMID:14620096

  8. Decompression Sickness During Simulated Low Pressure Exposure is Increased with Mild Ambulation Exercise

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Musculoskeletal activity accelerates inert gas elimination during oxygen breathing prior to decompression (prebreathe), but may also promote bubble formation (nucleation) and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity are likely critical to the net effect. The NASA Prebreathe Reduction Program (PRP) combined oxygen prebreathe and exercise preceding a 4.3 psia exposure in non-ambulatory subjects (a microgravity analog) to produce two protocols now used by astronauts preparing for extravehicular activity - one employing cycling and non-cycling exercise (CEVIS: 'cycle ergometer vibration isolation system') and one relying on non-cycling exercise only (ISLE: 'in-suit light exercise'). Current efforts investigate whether light exercise normal to 1 G environments increases the risk of DCS over microgravity simulation.

  9. Delayed hepatobiliary injury in a decompression sickness patient after scuba diving: case report.

    PubMed

    Kim, Hee Duck; Lee, Sang Hwan; Eom, Huisu; Kang, Young Joong

    2016-01-01

    We report here the first case of liver injury in a 51-year-old man following a dive to a depth of 40 meters. He presented with typical neurological symptoms affecting the lower limbs. Five days later, he experienced delayed abdominal pain, followed by rapidly progressive liver and adjacent organ injury due to air emboli in the intrahepatic portal vein. He received supportive care and hyperbaric therapy with a U.S. Navy Treatment Table 6 and recovered. Decompression sickness is a disease of protean manifestations. More information about venous gas emboli may be useful for better assessing decompression sickness. In this case, radiologic evaluation of the abdomen and the presentation of air bubbles in the portal vein in computed tomography played an essential role in diagnosing induced venous gas emboli in the liver and adjacent organs.

  10. Geodynamically unusual settings of sedimentary rock and ore formation due to tectonic-decompression effects

    SciTech Connect

    Goryainov, P.M.

    1984-05-01

    The traditional views of terrigenous rocks as products of classical sedimentary cycle, ''mobilization-transport-deposition,'' are not universal. Detrital rocks are sometimes formed due to flaking and fracturation of rocks of rising blocks. The process is produced by tectonic-decompression mechanisms - the origination of a gradient of excessive stress and its discharge. It is incorrect to classify rocks created by this phenomenon with weathering crusts. The origins of certain terrigenous rocks, as well as products of low-temperature chemical processing, are connected with deep-volume decompression (brecciation, stockwork formation, formation of pipes and columns of igneous rocks, and chamber pegmatite and karst formation). The ore concentrations associated with such entities and appearing as stratiform deposits are most likely not exogenous, but they complete the endogenous history of the block concerned. The means and methods tested on typical endogenous deposits may therefore prove valuable in predicting certain varieties of stratiform deposits.

  11. Minimally invasive endoscopic decompression of the intermatatarsal nerve for Morton's neuroma

    PubMed Central

    Kubota, Mitsuaki; Ohno, Ryuichi; Ishijima, Muneaki; Hanyu, Ryo; Sakai, Kensuke; Sugawara, Yu; Ochi, Hironori; Mukasa, Humihiro; Kaneko, Kazuo

    2015-01-01

    Background We presented case reports of endoscopic decompression for a Morton intermetatarsal neuroma. Methods Three patients underwent surgery using an instrument designed to release the transverse carpal ligament for carpal tunnel syndrome. Each patient was 61, 56 and 24 years old. The mean follow up period was 1.5 years. Results All patients experienced reduced pain postoperatively. The postoperative scar was very small (only 1 cm). There is no loss of sensation, no hematoma and no infection. Conclusion This procedure is simple, and the postoperative morbidity for the patient is minimal. There is rapid recovery with minimal risk of complications that are associated with open techniques. Therefore endoscopic decompression for Morton neuroma offers many advantages and should be studied in a larger number of patients. PMID:26719604

  12. Fully Endoscopic Vascular Decompression of the Facial Nerve for Hemifacial Spasm

    PubMed Central

    Eby, Joseph B.; Cha, Sung Tae; Shahinian, Hrayr K.

    2001-01-01

    Hemifacial spasm is an uncommon disorder manifesting as a unilateral, involuntary, sporadic contraction of the musculature innervated by the seventh cranial nerve. Although debated, the etiology of hemifacial spasm is generally accepted as compression of the facial nerve by vessels of the posterior circulation. Early surgical techniques were ineffective and fraught with morbidity. Over the past 25 years microvascular decompression surgery has allowed the safe and effective treatment of hemifacial spasm. Recent reports combining microsurgical and endoscopic techniques have documented the advantages of the endoscope in exposing the anatomy of this region. Enhanced visualization allows a less traumatic dissection and increases the surgeon's ability to locate nerve-vessel conflicts often difficult to identify through the limited view of the microscope. This article reviews the history of hemifacial spasm and describes the first three cases of fully endoscopic vascular decompression for hemifacial spasm, emphasizing the advantages of this novel surgical approach. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:17167620

  13. Delayed hepatobiliary injury in a decompression sickness patient after scuba diving: case report.

    PubMed

    Kim, Hee Duck; Lee, Sang Hwan; Eom, Huisu; Kang, Young Joong

    2016-01-01

    We report here the first case of liver injury in a 51-year-old man following a dive to a depth of 40 meters. He presented with typical neurological symptoms affecting the lower limbs. Five days later, he experienced delayed abdominal pain, followed by rapidly progressive liver and adjacent organ injury due to air emboli in the intrahepatic portal vein. He received supportive care and hyperbaric therapy with a U.S. Navy Treatment Table 6 and recovered. Decompression sickness is a disease of protean manifestations. More information about venous gas emboli may be useful for better assessing decompression sickness. In this case, radiologic evaluation of the abdomen and the presentation of air bubbles in the portal vein in computed tomography played an essential role in diagnosing induced venous gas emboli in the liver and adjacent organs. PMID:27416694

  14. Subchondral Insufficiency Fracture of the Femoral Head treated with Core Decompression and Bone Void Filler Support

    PubMed Central

    Patel, Hiren; Kamath, Atul F.

    2016-01-01

    Subchondral insufficiency fracture of the femoral head (SIFFH) is characterized by acute onset hip pain without overt trauma. It appears as a low intensity band with bone marrow edema on T1-weighted MRI. The most common course of treatment is protected weight bearing for a period of several weeks. Total hip arthroplasty (THA) has been commonly used if the patient does not respond to the initial protected weight bearing treatment. We present a case of a 48-year-old male with SIFFH who was treated with core hip decompression and bone void filler as a hip-preserving alternative to THA. The patient has an excellent clinical and radiographic result at final follow up. Core hip decompression with bone void filler is a less invasive alternative to THA, and may be a preferred initial treatment strategy for SIFFH in the young and active patient who has failed conservative measures. PMID:27517074

  15. A new technique in reference based DNA sequence compression algorithm: Enabling partial decompression

    NASA Astrophysics Data System (ADS)

    Banerjee, Kakoli; Prasad, R. A.

    2014-10-01

    The whole gamut of Genetic data is ever increasing exponentially. The human genome in its base format occupies almost thirty terabyte of data and doubling its size every two and a half year. It is well-know that computational resources are limited. The most important resource which genetic data requires in its collection, storage and retrieval is its storage space. Storage is limited. Computational performance is also dependent on storage and execution time. Transmission capabilities are also directly dependent on the size of the data. Hence Data compression techniques become an issue of utmost importance when we confront with the task of handling such giganticdatabases like GenBank. Decompression is also an issue when such huge databases are being handled. This paper is intended not only to provide genetic data compression but also partially decompress the genetic sequences.

  16. Spontaneous Resolution of a Large Chronic Subdural Hematoma Which Required Surgical Decompression.

    PubMed

    Lee, Gun Seok; Park, Young Seok; Min, Kyung Soo; Lee, Mou Seop

    2015-09-01

    We report on a case of an 87-year-old woman who showed spontaneous resolution of a large chronic subdural hematoma which required surgical decompression. She had suffered from confused mentality and right side weakness of motor grade II for 10 days. The initial brain CT scan showed a 22 mm thick low density lesion located in the left fronto-temporo-parietal region with midline shift (12 mm) which required emergency decompression. However, because she and her family did not want surgery, she was followed up in the outpatient clinic. Five months later, follow up brain CT showed that the CSDH had disappeared and the patient became neurologically normal. The reasons for spontaneous resolution of CSDH remain unclear. We discuss the possible relation between mechanisms of physio-pathogenesis and spontaneous resolution of a large chronic subdural hematoma (CSH) in an elderly patient. PMID:26539279

  17. Inhibitors of ex vivo aggregation of human platelets induced by decompression, during reduced barometric pressure.

    PubMed

    Murayama, M; Kumaroo, K K

    1986-05-15

    It has been shown experimentally ex vivo that human platelet aggregation is induced by decompression (reduced pressure) produced by various means, i.e., reduced barometric pressure, reduced hydrostatic pressure, and reduced hydrodynamic pressure due to Bernoulli's principle. We report here that the spontaneous platelet aggregation induced by reduced barometric pressure (253 torr for three hours) is inhibited by 1:10(7) diluted Japanese herbal plant oil (JHP) and also by two of its major constituents, menthone and menthol with the median inhibitory concentration (IC50) in the millimolar range. These drugs gave essentially similar results when collagen and ADP were used as aggregating agents. Inhibitor concentrations were determined by microscopic examination of platelets in wet preparations when the aggregating stimulus was reduced pressure and by optical aggregometry when collagen and ADP were the aggregating agents. Potential usefulness of these compounds in the prevention of decompression syndrome (DCS) and acute mountain sickness (AMS) are discussed.

  18. Case report on a diver with type II decompression sickness and viral meningitis.

    PubMed

    Beckman, T J; Mullins, M E; Matthews, M D

    1996-12-01

    A 33-yr-old man came to the emergency department with the chief complaint of a severe headache and decreased sensation in his right hand following a deep dive on scuba. Physical examination before recompression treatment was remarkable only for hypesthesia on the right hand. We diagnosed type II decompression sickness and the patient underwent standard recompression therapy. The patient experienced near-complete resolution of his symptoms, his only residual complaint being that of neck pain with head movement. To investigate other causes of headache, a computed tomography of the head was performed which was normal, and a lumbar puncture was performed which was consistent with viral meningitis. This is the first reported case of recompression treatment on a patient with viral meningitis and decompression sickness. PMID:8989855

  19. Blood biochemical and cellular changes during decompression and simulated extravehicular activity

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.; Waligora, J. M.; Johnson, P. C. Jr

    1990-01-01

    Blood biochemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 6 h of oxygen prebreathing. The exposure was designed to simulate extravehicular activity for 6 h (subjects performed exercise while exposed to 29.6 kPa). There were no significant differences between blood samples from subjects who were susceptible (n = 11) versus those who were resistant (n = 27) to formation of venous gas emboli. Although several statistically significant (P less than 0.05) changes in blood parameters were observed following the exposure (increases in white blood cell count, prothrombin time, and total bilirubin, and decreases in triglycerides, very-low-density lipoprotein cholesterol, and blood urea nitrogen), the changes were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression schedule used in this study is not likely to result in blood changes that would pose a threat to astronauts during extravehicular activity.

  20. [Medical aspects of diving in otorhinolaryngology. I. Barotrauma and decompression sickness].

    PubMed

    Dieler, R; Shehata-Dieler, W E

    2000-12-01

    Recreational scuba diving has become immensely popular in recent years and is no longer restricted to individualists or adventurers. During a dive, the human body with its gas-filled cavities is exposed to an increased ambient pressure. In the present review article, aspects of diving and hyperbaric medicine related to the otolaryngology field are presented. The basics of physics, physiology and pathophysiology that are essential to understand the effects of an increased and varying ambient pressure are reviewed. Barotrauma of the outer, middle and inner ear, the paranasal sinuses, face, teeth and larynx are explained and classified in those during the compression and decompression phase. This is followed by a discussion of inner ear decompression sickness. The present article will provide a background and foundation for both, an adequate treatment of these diseases and a critical and responsible health education of the diver.

  1. Diving into the rat plasma proteome to get to the bottom of decompression sickness.

    PubMed

    Eftedal, Ingrid

    2016-07-01

    Decompression sickness (DCS) is the collective term for an array of signs and symptoms triggered by ambient pressure reduction. It is of particular concern to divers as they decompress on ascend from depth to sea surface, but despite a long history of studies the determinants of DCS risk are incompletely understood and there are no validated biomarkers. In this issue of Proteomics Clinical Applications, Lautridou et al. [8] report on their search for DCS biomarkers in rats exposed to simulated diving. By comparing the plasma proteomes from animals showing neurological symptoms to those emerging from dives unaffected, they identified several high-abundance proteins not previously associated with DCS. The most significant finding was a near depletion of thyroxine- and vitamin A transporter transthyretin in symptomatic rats. In addition to their potential role as diagnostic biomarkers, the proteins identified in Lautridou's study may offer new pieces in the yet incomplete puzzle of DCS etiology. PMID:27196271

  2. Microsurgical decompression of tumor of a rare posterior third ventricular pathology.

    PubMed

    Nanda, Anil; Konar, Subhas; Kalakoti, Piyush; Maiti, Tanmoy

    2016-01-01

    Of the posterior third ventricular tumors, a papillary tumor of the pineal gland is a rare entity that originates from specialized ependymoma of the subcommissural organ. In this video narration, we present a case of a 33-year-old male with headaches and recent cognitive decline due to a posterior third ventricular lesion. The patient underwent a posterior interhemispheric approach, and a gross-total decompression was achieved with no signs of recurrence in a 2-year follow-up period. With this case we highlight the microsurgical technique employed for decompressing tumors of the posterior third ventricular region with preservation of eloquent structures and draining veins. The video can be found here: https://youtu.be/o0WbyOqmtX0 . PMID:26722689

  3. Survival following decompressive hemicraniectomy for hemiconvulsion-hemiplegia-epilepsy syndrome: case report.

    PubMed

    Beier, Alexandra D; Jannotta, Gemi E; Sandler, E Dayan; Abram, Harry S; Sheth, Raj D; Aldana, Philipp R

    2016-09-01

    Hemiconvulsion-hemiplegia-epilepsy (HHE) is an uncommon epileptic syndrome that affects young children. Typical management includes early initiation of benzodiazepines to abate the initial seizure activity quickly. Patients in whom epilepsy develops require prolonged use of antiepileptic agents. Herniation due to diffuse cerebral edema from HHE is rare; however, decompressive craniectomy has been described as a lifesaving measure. The authors present the case of a patient in whom a decompressive craniectomy was performed. They advocate a proactive approach in the detection and management of cerebral edema in HHE causing intracranial hypertension. In HHE cases that exhibit radiographic evidence of malignant cerebral edema (although not previously described in this disease, but similar to the setting of stroke and trauma), the authors advocate early neurosurgical consultation and evaluation for insertion of an intracranial pressure monitor for those patients who do not have a reliable neurological examination (i.e., Glasgow Coma Scale score ≤ 8). PMID:27176609

  4. Enhancement of KTP/532 laser disc decompression and arthroscopic microdiscectomy with a vital dye

    NASA Astrophysics Data System (ADS)

    Yeung, Anthony T.

    1993-07-01

    Currently, the clinical indications and results of arthroscopic microdiscectomy and laser disc decompression come close to, but do not exceed, the results of classic discectomy or microdiscectomy for the whole spectrum of surgical disc herniations. However, as minimally invasive techniques continue to evolve, results can be expected to equal or be potentially superior to conventional surgery. This exhibit demonstrates how the use of a vital dye can enhance standard arthroscopic microdiscectomy techniques and, when used in conjunction with KTP/532 laser disc decompression, allows for better arthroscopic visualization, documentation, and extraction of nucleus pulposus, ultimately expanding the current limiting criteria for minimally invasive techniques. When proper patient selection is combined with good clinical indications, the surgical results are rather dramatic, often achieving immediate relief of sciatica in the operating room.

  5. Extreme Scale Visual Analytics

    SciTech Connect

    Wong, Pak C.; Shen, Han-Wei; Pascucci, Valerio

    2012-05-08

    Extreme-scale visual analytics (VA) is about applying VA to extreme-scale data. The articles in this special issue examine advances related to extreme-scale VA problems, their analytical and computational challenges, and their real-world applications.

  6. Timescales of bubble coalescence, outgassing, and foam collapse in decompressed rhyolitic melts

    NASA Astrophysics Data System (ADS)

    Martel, Caroline; Iacono-Marziano, Giada

    2016-04-01

    The timescale of degassing and outgassing in hydrous rhyolitic melts is investigated in a wide range of conditions by means of decompression experiments. The evolution of vesicularity, bubble diameter, and number density is characterized as a function of time either of decompression or spent at final pressure, in order to determine the effect of final pressure, temperature, syn- versus post-decompression degassing, melt composition, and microlites, on the timescale of bubble growth, coalescence, and outgassing. The result suggest that different bubble evolution and degassing-outgassing timescale corresponding to explosive and effusive eruption regimes can be cast in bulk viscosity (melt + bubbles; nbulk) versus decompression time (rather than path) space. The nbulk-time relationships defines three domains of (i) bubble nucleation and growth, restricted to short durations and high nbulk (< ˜0.03 h for nbulk ˜105‑6Pa.s), (ii) equilibrium degassing with coalescence increasing from negligible (permeability > 10‑13 m2) to extensive (permeability ˜10‑11‑12 m2), and (iii) outgassing, restricted to long durations and low nbulk(> ˜10 h for nbulk < 106 Pa.s; permeability >10‑10 m2) that eventually leads to foam collapse. These findings are applied to the case studies of Mt Pelée and Mt Pinatubo to infer the transition from pumice to dense pyroclasts in volcanic eruptions and the possibility of evolving from an explosive Plinian eruption to an effusive dome-growth event by giving the vesicular magma enough time to outgas and collapse (i.e. hundreds to tens of hours for nbulk ˜105 to 104 Pa.s, respectively). We also show the drastic effect of microlites on re-arranging preexistent bubbles and potentially triggering a late nucleation event.

  7. Analysis of the individual risk of altitude decompression sickness under repeated exposures

    NASA Technical Reports Server (NTRS)

    Kumar, K. Vasantha; Horrigan, David J.; Waligora, James M.; Gilbert, John H.

    1991-01-01

    In a case-control study, researchers examined the risk of decompression sickness (DCS) in individual subjects with higher number of exposures. Of the 126 subjects, 42 showed one or more episodes of DCS. Examination of the exposure-DCS relationship by odds ratio showed a linear relationship. Stratification analysis showed that sex, tissue ratio, and the presence of Doppler microbubbles were cofounders of this risk. A higher number of exposures increased the risk of DCS in this analysis.

  8. Integrating Laboratory and Numerical Decompression Experiments to Investigate Fluid Dynamics into the Conduit

    NASA Astrophysics Data System (ADS)

    Spina, Laura; Colucci, Simone; De'Michieli Vitturi, Mattia; Scheu, Bettina; Dingwell, Donald Bruce

    2015-04-01

    The study of the fluid dynamics of magmatic melts into the conduit, where direct observations are unattainable, was proven to be strongly enhanced by multiparametric approaches. Among them, the coupling of numerical modeling with laboratory experiments represents a fundamental tool of investigation. Indeed, the experimental approach provide invaluable data to validate complex multiphase codes. We performed decompression experiments in a shock tube system, using pure silicon oil as a proxy for the basaltic melt. A range of viscosity comprised between 1 and 1000 Pa s was investigated. The samples were saturated with Argon for 72h at 10MPa, before being slowly decompressed to atmospheric pressure. The evolution of the analogue magmatic system was monitored through a high speed camera and pressure sensors, located into the analogue conduit. The experimental decompressions have then been reproduced numerically using a multiphase solver based on OpenFOAM framework. The original compressible multiphase Openfoam solver twoPhaseEulerFoam was extended to take into account the multicomponent nature of the fluid mixtures (liquid and gas) and the phase transition. According to the experimental conditions, the simulations were run with values of fluid viscosity ranging from 1 to 1000 Pa s. The sensitivity of the model has been tested for different values of the parameters t and D, representing respectively the relaxation time for gas exsolution and the average bubble diameter, required by the Gidaspow drag model. Valuable range of values for both parameters are provided from experimental observations, i.e. bubble nucleation time and bubble size distribution at a given pressure. The comparison of video images with the outcomes of the numerical models was performed by tracking the evolution of the gas volume fraction through time. Therefore, we were able to calibrate the parameter of the model by laboratory results, and to track the fluid dynamics of experimental decompression.

  9. [Hypobaric atmosphere and decompression safety of outer space explorations on the first days of flight].

    PubMed

    Chadov, V I; Iseev, L R; Tsivilashvili, A S

    1993-01-01

    54 subjects aged 21-47 participated in 8 series of experiments (298 altitude investigations) aimed at selecting decompression-safe protocols for transition from hypobaric normoxic environment to reduced pressure. Experimental data is discussed and some protocols for safe transition to reduced pressure are recommended. The experiments allowed to display in diagram form the ratio of permissible magnitudes of residual pressure (the working pressure in the extravehicular suit) to the duration of a preliminary exposure in normoxic hypobaric conditions.

  10. Evaluation of Outcome of Posterior Decompression and Instrumented Fusion in Lumbar and Lumbosacral Tuberculosis

    PubMed Central

    Jain, Ravikant; Kiyawat, Vivek

    2016-01-01

    Background For surgical treatment of lumbar and lumbosacral tuberculosis, the anterior approach has been the most popular approach because it allows direct access to the infected tissue, thereby providing good decompression. However, anterior fixation is not strong, and graft failure and loss of correction are frequent complications. The posterior approach allows circumferential decompression of neural elements along with three-column fixation attained via pedicle screws by the same approach. The purpose of this study was to evaluate the outcome (functional, neurological, and radiological) in patients with lumbar and lumbosacral tuberculosis operated through the posterior approach. Methods Twenty-eight patients were diagnosed with tuberculosis of the lumbar and lumbosacral region from August 2012 to August 2013. Of these, 13 patients had progressive neurological deterioration or increasing back pain despite conservative measures and underwent posterior decompression and pedicle screw fixation with posterolateral fusion. Antitubercular therapy was given till signs of radiological healing were evident (9 to 16 months). Functional outcome (visual analogue scale [VAS] score for back pain), neurological recovery (Frankel grading), and radiological improvement were evaluated preoperatively, immediately postoperatively and 3 months, 6 months, and 1 year postoperatively. Results The mean VAS score for back pain improved from 7.89 (range, 9 to 7) preoperatively to 2.2 (range, 3 to 1) at 1-year follow-up. Frankel grading was grade B in 3, grade C in 7, and grade D in 3 patients preoperatively, which improved to grade D in 7 and grade E in 6 patients at the last follow-up. Radiological healing was evident in the form of reappearance of trabeculae formation, resolution of pus, fatty marrow replacement, and bony fusion in all patients. The mean correction of segmental kyphosis was 9.85° postoperatively. The mean loss of correction at final follow-up was 3.15°. Conclusions

  11. [Current management of diving-related spinal cord decompression sickness in 2010].

    PubMed

    Louge, Pierre; Gempp, Emmanuel; Constantin, Pascal; Hugon, Michel

    2010-01-01

    The outcome of spinal cord decompression sickness after scuba diving is unpredictable during the 24 first hours with a high risk of incomplete recovery. The treatment is defined on first aid normobaric oxygen when neurological symptoms occur, rehydration and prompt recompression in hyperbaric chamber. The presence of initial motor impairment, the aggravation of symptoms during the transfer to the hyperbaric facility and the emergence of sphincter dysfunction are predictive of poor prognosis whatever the treatment undertaken.

  12. Timescales of bubble coalescence, outgassing, and foam collapse in decompressed rhyolitic melts

    NASA Astrophysics Data System (ADS)

    Martel, Caroline; Iacono-Marziano, Giada

    2016-04-01

    The timescale of degassing and outgassing in hydrous rhyolitic melts is investigated in a wide range of conditions by means of decompression experiments. The evolution of vesicularity, bubble diameter, and number density is characterized as a function of time either of decompression or spent at final pressure, in order to determine the effect of final pressure, temperature, syn- versus post-decompression degassing, melt composition, and microlites, on the timescale of bubble growth, coalescence, and outgassing. The result suggest that different bubble evolution and degassing-outgassing timescale corresponding to explosive and effusive eruption regimes can be cast in bulk viscosity (melt + bubbles; nbulk) versus decompression time (rather than path) space. The nbulk-time relationships defines three domains of (i) bubble nucleation and growth, restricted to short durations and high nbulk (< ˜0.03 h for nbulk ˜105-6Pa.s), (ii) equilibrium degassing with coalescence increasing from negligible (permeability > 10-13 m2) to extensive (permeability ˜10-11-12 m2), and (iii) outgassing, restricted to long durations and low nbulk(> ˜10 h for nbulk < 106 Pa.s; permeability >10-10 m2) that eventually leads to foam collapse. These findings are applied to the case studies of Mt Pelée and Mt Pinatubo to infer the transition from pumice to dense pyroclasts in volcanic eruptions and the possibility of evolving from an explosive Plinian eruption to an effusive dome-growth event by giving the vesicular magma enough time to outgas and collapse (i.e. hundreds to tens of hours for nbulk ˜105 to 104 Pa.s, respectively). We also show the drastic effect of microlites on re-arranging preexistent bubbles and potentially triggering a late nucleation event.

  13. The Decompression Sickness and Venous Gas Emboli Consequences of Air Breaks During 100% Oxygen Prebreathe

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Gernhardt, Michael L.; Powell, Michael R.

    2005-01-01

    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.

  14. An abscess causing a delayed optic neuropathy after decompression for thyroid eye disease.

    PubMed

    Patel, Rakesh M; Aakalu, Vinay K; Joe, Stephanie; Setabutr, Pete

    2014-02-01

    A 63-year-old female with Graves' disease and chronic sinusitis presented with acute left orbital pain and proptosis five years after bilateral orbital decompression and sinus surgery. Imaging revealed bilateral frontal sinus opacification, frontoethmoidal mucoceles and left subperiosteal mass. Presence of an optic neuropathy drove emergent management with intravenous antibiotics and orbitotomy with exploration. Intra-operatively, a left orbital abscess and left frontal sinus purulence were drained. The patient regained her vision with relief of proptosis and pain. PMID:24144317

  15. Decompressive craniectomy in malignant middle cerebral artery infarct: An institutional experience

    PubMed Central

    Bansal, Hanish; Chaudhary, Ashwani; Singh, Apinderpreet; Paul, Birinder; Garg, Rajveer

    2015-01-01

    Introduction: Decompressive craniectomy as a surgical treatment for brain edema has been performed for many years and for several different pathophysiologies, including malignant middle cerebral artery (MCA) infarct. The purpose of this article was to share author's experience with decompressive craniectomy in malignant MCA infarct with special emphasis on patients older than 60 years and those operated outside 48 h after onset of stroke. Materials and Methods: Totally, 53 patients who underwent decompressive craniectomy after malignant MCA infarction between January 2012 and May 2014 at tertiary care hospital were analyzed for preoperative clinical condition, timing of surgery, cause of infarction, and location and extension of infarction. The outcome was assessed in terms of mortality and scores like modified Rankin scale (mRS). Results: Totally, 53 patients aged between 22 and 80 years (mean age was 54.92 ± 11.8 years) were analyzed in this study. Approximately, 60% patients were older than 60 years. Approximately, 74% patients operated within 48 h (25 patients) had mRS 0–3 at discharge while 56% patients operated after 48 h had mRS 0–3 at discharge which is not significant statistically. 78% patients aged below 60 years had mRS 0–3 at discharge while only 38% patients aged above 60 years had mRS 0–3 at discharge which was statistically significant (P < 0.008). Conclusion: Decompressive craniectomy has reduced morbidity and mortality especially in people aged below 60 years and those operated within 48 h of malignant MCA stroke though those operated outside 48 h of stroke also fare well neurologically, there is no reason these patients should be denied surgery. PMID:26396607

  16. Benign paroxysmal positional vertigo after decompression sickness: a first case report and review of the literature.

    PubMed

    Dan-Goor, Eric; Eden, Julian C P; Wilson, Simon J; Dangoor, Joseph; Wilson, Benjamin R

    2010-01-01

    Benign paroxysmal positional vertigo is a common cause of vertigo. We describe a previously unreported case of this clinical entity in a young, fit recreational water diver, having experienced decompression illness. Full recovery occurred after hyperbaric recompression therapy, and he remained symptom free on 6-week follow-up. We review the literature and discuss the pathogenesis of benign paroxysmal positional vertigo, proposing that semicircular canal nitrogen bubble formation could have been the primary etiological event leading to this condition.

  17. Plagioclase nucleation and growth kinetics in a hydrous basaltic melt by decompression experiments

    NASA Astrophysics Data System (ADS)

    Arzilli, Fabio; Agostini, C.; Landi, P.; Fortunati, A.; Mancini, L.; Carroll, M. R.

    2015-12-01

    Isothermal single-step decompression experiments (at temperature of 1075 °C and pressure between 5 and 50 MPa) were used to study the crystallization kinetics of plagioclase in hydrous high-K basaltic melts as a function of pressure, effective undercooling (Δ T eff) and time. Single-step decompression causes water exsolution and a consequent increase in the plagioclase liquidus, thus imposing an effective undercooling (∆ T eff), accompanied by increased melt viscosity. Here, we show that the decompression process acts directly on viscosity and thermodynamic energy barriers (such as interfacial-free energy), controlling the nucleation process and favoring the formation of homogeneous nuclei also at high pressure (low effective undercoolings). In fact, this study shows that similar crystal number densities ( N a) can be obtained both at low and high pressure (between 5 and 50 MPa), whereas crystal growth processes are favored at low pressures (5-10 MPa). The main evidence of this study is that the crystallization of plagioclase in decompressed high-K basalts is more rapid than that in rhyolitic melts on similar timescales. The onset of the crystallization process during experiments was characterized by an initial nucleation event within the first hour of the experiment, which produced the largest amount of plagioclase. This nucleation event, at short experimental duration, can produce a dramatic change in crystal number density ( N a) and crystal fraction ( ϕ), triggering a significant textural evolution in only 1 h. In natural systems, this may affect the magma rheology and eruptive dynamics on very short time scales.

  18. Modeling dissolved and free phase gas dynamics under decompression.

    PubMed

    Wienke, B R

    1990-04-01

    Dissolved and free gases do not behave the same way in tissue under pressure, and their interaction is complex. Differences are highlighted, particularly with respect to time scales, gradients and transport. Impacts of free phases on diving are described, contrasting increased off-gassing pressures, slower ascent rates, safety stops and reduced repetitive exposures as consistent practical measures within Haldane models (limited supersaturation) which can be played off against buildup of dissolved gas. Simple computations illustrate the points.

  19. Nonaffine deformation under compression and decompression of a flow-stabilized solid

    NASA Astrophysics Data System (ADS)

    Ortiz, Carlos P.; Riehn, Robert; Daniels, Karen E.

    2016-08-01

    Understanding the particle-scale transition from elastic deformation to plastic flow is central to making predictions about the bulk material properties and response of disordered materials. To address this issue, we perform experiments on flow-stabilized solids composed of micron-scale spheres within a microfluidic channel, in a regime where particle inertia is negligible. Each solid heap exists within a stress field imposed by the flow, and we track the positions of particles in response to single impulses of fluid-driven compression or decompression. We find that the resulting deformation field is well-decomposed into an affine field, with a constant strain profile throughout the solid, and a non-affine field. The magnitude of this non-affine response decays with the distance from the free surface in the long-time limit, suggesting that the distance from jamming plays a significant role in controlling the length scale of plastic flow. Finally, we observe that compressive pulses create more rearrangements than decompressive pulses, an effect that we quantify using the D\\text{min}2 statistic for non-affine motion. Unexpectedly, the time scale for the compression response is shorter than for decompression at the same strain (but unequal pressure), providing insight into the coupling between deformation and cage-breaking.

  20. Decompression of the Sciatic Nerve Entrapment Caused by Post-Inflammatory Scarring

    PubMed Central

    Kim, Deog-ryeong; Jeun, Sin Soo; Lee, Sang-won

    2015-01-01

    A rare case of chronic pain of entrapment neuropathy of the sciatic nerve successfully relieved by surgical decompression is presented. A 71-year-old male suffered a chronic right buttock pain of duration of 7 years which radiating to the right distal leg and foot. His pain developed gradually over one year after underwenting drainage for the gluteal abscess seven years ago. A cramping buttock and intermittently radiating pain to his right foot on sitting, walking, and voiding did not respond to conventional treatment. An MRI suggested a post-inflammatory adhesion encroaching the proximal course of the sciatic nerve beneath the piriformis as it emerges from the sciatic notch. Upon exploration of the sciatic nerve, a fibrotic tendinous scar beneath the piriformis was found and released proximally to the sciatic notch. His chronic intractable pain was completely relieved within days after the decompression. However, thigh weakness and hypesthesia of the foot did not improve. This case suggest a need for of more prompt investigation and decompression of the chronic sciatic entrapment neuropathy which does not improve clinically or electrically over several months. PMID:25733994

  1. Network model to study physiological processes of hypobaric decompression sickness: New numerical results

    NASA Astrophysics Data System (ADS)

    Zueco, Joaquín; López-González, Luis María

    2016-04-01

    We have studied decompression processes when pressure changes that take place, in blood and tissues using a technical numerical based in electrical analogy of the parameters that involved in the problem. The particular problem analyzed is the behavior dynamics of the extravascular bubbles formed in the intercellular cavities of a hypothetical tissue undergoing decompression. Numerical solutions are given for a system of equations to simulate gas exchanges of bubbles after decompression, with particular attention paid to the effect of bubble size, nitrogen tension, nitrogen diffusivity in the intercellular fluid and in the tissue cell layer in a radial direction, nitrogen solubility, ambient pressure and specific blood flow through the tissue over the different molar diffusion fluxes of nitrogen per time unit (through the bubble surface, between the intercellular fluid layer and blood and between the intercellular fluid layer and the tissue cell layer). The system of nonlinear equations is solved using the Network Simulation Method, where the electric analogy is applied to convert these equations into a network-electrical model, and a computer code (electric circuit simulator, Pspice). In this paper, numerical results new (together to a network model improved with interdisciplinary electrical analogies) are provided.

  2. Compositional Discrimination of Decompression and Decomposition Gas Bubbles in Bycaught Seals and Dolphins

    PubMed Central

    Bernaldo de Quirós, Yara; Seewald, Jeffrey S.; Sylva, Sean P.; Greer, Bill; Niemeyer, Misty; Bogomolni, Andrea L.; Moore, Michael J.

    2013-01-01

    Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis. PMID:24367623

  3. Influence of Rectal Decompression on Abdominal Symptoms and Anorectal Physiology following Colonoscopy in Healthy Adults

    PubMed Central

    Yi, Chih-Hsun; Liu, Tso-Tsai; Lei, Wei-Yi; Hung, Jui-Sheng

    2016-01-01

    Background. Postcolonoscopy abdominal discomfort and bloating are common. The aim of this study was to evaluate whether rectal decompression improved distension-induced abdominal symptoms and influenced anorectal physiology. Methods. In 15 healthy subjects, rectal distension was achieved by direct air inflation into the rectum by colonoscopy. Placement of rectal and sham tube was then performed in each subject on a separate occasion. The anorectal parameters and distension-induced abdominal symptoms were recorded. Results. Anorectal parameters were similar between placements of rectal tube and sham tube except for greater rectal compliance with rectal tube than with sham tube (P < 0.05). Abdominal pain and bloating were significantly reduced by rectal tube and sham tube at 1 minute (both P < 0.05) and 3 minutes (both P < 0.05). After placement of rectal tube, abdominal pain at 3 minutes correlated positively with first sensation (r = 0.53, P = 0.04), and bloating at 3 minutes also correlated positively with urge sensation (r = 0.55, P = 0.03). Conclusions. Rectal decompression with either rectal or sham tube improved distension-induced abdominal symptoms. Our study indicates that the mechanisms that improved abdominal symptoms by rectal decompression might be mediated by a central pathway instead of a peripheral mechanism.

  4. Compositional discrimination of decompression and decomposition gas bubbles in bycaught seals and dolphins.

    PubMed

    Bernaldo de Quirós, Yara; Seewald, Jeffrey S; Sylva, Sean P; Greer, Bill; Niemeyer, Misty; Bogomolni, Andrea L; Moore, Michael J

    2013-01-01

    Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis. PMID:24367623

  5. Bilateral decompression of multilevel lumbar spinal stenosis through a unilateral approach.

    PubMed

    Haba, Katsuhiko; Ikeda, Masato; Soma, Mariko; Yamashima, Tetsumori

    2005-02-01

    Lumbar canal stenosis due to hypertrophy and calcification of the facet joints and/or ligamentum flavum is a common condition in the elderly. Although a large number of individuals are symptom-free, the degenerative process, usually encroaching on both central and lateral pathways, may lead to symptoms of itself or decompensate a preexisting narrow canal. Even at an advanced age, decompression surgery is effective for symptomatic stenosis. Less invasive procedures preserving maximal bony and ligamentous structures have recently been recommended to reduce associated morbidity. This paper introduces a unilateral surgical approach for bilateral decompression by ligamentectomy, partial facetectomy and foraminal unroofing. Using a specially designed, one-side retractor, after the ipsilateral nerve root decompression the contralateral dural sac and nerve roots were approached through an 8 x 15 mm window in the interspinous ligament. The contralateral ligamentum flavum, facet joints and foraminal roof were resected, preserving the supraspinous ligament complex and much of the contralateral musculature. This technique, preserving anatomy and biomechanical function of the lumbar spine, is useful for surgery on multilevel lumbar canal stenoses.

  6. Dominant time scale for brittle fragmentation of vesicular magma by decompression

    NASA Astrophysics Data System (ADS)

    Kameda, Masaharu; Kuribara, Hideaki; Ichihara, Mie

    2008-07-01

    Brittle fragmentation was examined in a vesicular material analogous to magma, in this case, maltose syrup with bubbles. All the key time scales for magma fragmentation are controlled in the experiment using a rapid decompression facility. It was found that the onset of fragmentation can be well characterized using the Maxwell relaxation time τ r and the decompression time Δt dec, in the case where sufficiently large stress is generated in the material. As the ratio Δt dec/τ r increases from less than unity to over fifty, the response of the specimen changes from brittle fragmentation to ductile expansion without fragmentation. During the transition, the specimen exhibits small ductile deformation before the onset of fragmentation. The transition occurs even though the stress at the bubble wall is the same. The results suggest that Δt dec/τ r is the controlling parameter not only for the onset of, but also for the variation of magma fragmentation by decompression.

  7. Decompressive Hemicraniectomy in a South American Population – Morbidity and Outcomes Analysis

    PubMed Central

    Vital, Roberto Bezerra; Hamamoto Filho, Pedro Tadao; Luvizutto, Gustavo Jose; Ducati, Luis Gustavo; Braga, Gabriel Pereira; Nunes, Helio Rubens de Carvalho; Romero, Flavio Ramalho; Ganem, Eliana Marisa; Zanini, Marco Antonio; Bazan, Rodrigo

    2016-01-01

    Background Malignant cerebral artery strokes have a poor prognosis, with nearly 80% of mortality in some series despite intensive care. After a large randomized trial, decompressive hemicraniectomy has been performed more often in stroke patients. Here, we describe patients in a tertiary teaching hospital in Brazil, emphasizing the impact of age on outcomes. Methods A retrospective cohort of patients, with malignant strokes which received a decompressive hemicraniectomy, from paper and electronic medical records, from January 2010 to December 2013 was divided into two groups according to age. Results The final analysis included 60 patients. The overall mortality was higher among patients older than 60 yrs (67% vs. 41%; p = 0.039), whose group also had a worse outcome (76% with mRS 5 or 6) at 90 days (OR 3.91 CI95% 1.30–11.74), whereas only 24% had mRS of 0–4 (p = 0.015). All patients who presented with sepsis died (p = 0.003). The incidence of pulmonary infection was very high in the elderly group (76%) with significant intergroup differences (p = 0.027, OR 8.32 CI95% 0.70–98.48). Conclusions Older patients present more commonly with infections, more disabilities and a higher mortality, highlighting very poor results in elderly population. These results should be proved with a South American trial, and if confirmed, it can impact on future decisions regarding decompressive craniectomy for acute ischemic stroke in our region. PMID:26764485

  8. The influence of prior exercise at anaerobic threshold on decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.; Gilbert, John H., III

    1992-01-01

    This study was conducted to examine the effects of exercise prior to decompression on the incidence of altitude decompression sickness (DCS). In a balanced, two-period, crossover trial, 39 healthy individuals were each exposed twice, without denitrogenation, to an altitude of 6400 m in a hypobaric chamber. Under the experimental condition, subjects exercised at their predetermined anaerobic threshold levels for 30 min each day for 3 d prior to altitude exposure; the other condition was a non-exercise control. Under both conditions, subjects performed exercise simulating space extravehicular activities at altitude for a period of 3 h, while breathing 100 percent oxygen. There were nine preferences (untied responses) for DCS, four under control and five under experimental conditions; all were Type I, pain-only bends. No carry-over effects between exposures was detected, and the test for treatment differences showed p = 0.56 for symptoms. No significant difference in DCS preferences was found after subjects exercised up to their anaerobic threshold levels during the days prior to decompression.

  9. Risk factors for diskospondylitis in dogs after spinal decompression surgery for intervertebral disk herniation.

    PubMed

    Canal, Sara; Contiero, Barbara; Balducci, Federica; Calò, Pietro; Bernardini, Marco

    2016-06-15

    OBJECTIVE To determine the incidence of and risk factors for development of postoperative diskospondylitis (POD) in dogs that underwent spinal decompression surgery for intervertebral disk herniation (IVDH). DESIGN Retrospective single cohort study. ANIMALS 372 dogs that underwent spinal decompression surgery for IVDH between January 2007 and January 2011. PROCEDURES Medical records of dogs were retrospectively reviewed. Data regarding signalment, type and anatomic site of IVDH, severity of neurologic signs, type of surgery, duration of anesthesia, esophageal temperature during surgery, and use of corticosteroid drugs were analyzed for associations with POD. RESULTS POD developed in 8 of 372 (2.2%) dogs. Univariate analysis revealed that German Shepherd Dogs had 9.8 times the odds of POD, compared with the odds for other breeds. In addition, dogs > 8.8 years of age, weighing > 20 kg (44 lb), or having disk protrusions were at higher risk of developing POD than were other dogs. The only factor that retained a significant association with POD after controlling for other factors in multivariate analysis was body weight > 20 kg. CONCLUSIONS AND CLINICAL RELEVANCE Factors identified in this study may be useful for prediction of POD, an apparently uncommon outcome, in dogs undergoing spinal decompression surgery for IVDH. Dogs at higher risk than others, particularly those weighing > 20 kg, should be monitored carefully in the immediate postoperative period, and signs of worsening neurologic condition after initial improvement should be promptly investigated.

  10. Efficacy of Transcutaneous Transseptal Orbital Decompression in Treating Acute Retrobulbar Hemorrhage and a Literature Review

    PubMed Central

    Zimmerer, Rüdiger; Schattmann, Katrin; Essig, Harald; Jehn, Philipp; Metzger, Marc; Kokemüller, Horst; Gellrich, Nils-Claudius; Tavassol, Frank

    2013-01-01

    Decreasing visual acuity secondary to orbital trauma may be caused by sudden space-occupying or expanding intraorbital lesions, including retrobulbar hemorrhage (RBH), herniation, or swelling. RBH must be diagnosed and treated immediately. This article addresses the efficacy of transcutaneous transseptal orbital decompression in a combination with a systematic review of the literature for a comparison of this method with existing treatment options. For this study the department's database was retrospectively screened for patients with acute RBH who were treated between 2009 and 2011 using the authors' approach. Patients presenting with RBH were classified into RBH classes I to III according to three different clinical and radiological manifestations of acute RBH. The efficacy of transcutaneous transseptal orbital decompression was assessed by postoperative visual acuities. The literature review was performed by using the MEDLINE database. The time period for the study was between 2009 and 2011 during which 10 patients were diagnosed with suspected RBH and 9 were treated with the authors' technique. Visual acuities were reconstituted or maintained in almost 86% of patients who were diagnosed and treated according to the authors approach and who survived initial trauma. It was concluded that transcutaneous transseptal orbital decompression provides an efficient and rapid approach for treating patients with acute RBH. By distinguishing three different manifestations of acute RBH, the authors present a diagnostic tool that may facilitate classification of RBH and determination of treatment options. PMID:24624253

  11. DSP accelerator for the wavelet compression/decompression of high- resolution images

    SciTech Connect

    Hunt, M.A.; Gleason, S.S.; Jatko, W.B.

    1993-07-23

    A Texas Instruments (TI) TMS320C30-based S-Bus digital signal processing (DSP) module was used to accelerate a wavelet-based compression and decompression algorithm applied to high-resolution fingerprint images. The law enforcement community, together with the National Institute of Standards and Technology (NISI), is adopting a standard based on the wavelet transform for the compression, transmission, and decompression of scanned fingerprint images. A two-dimensional wavelet transform of the input image is computed. Then spatial/frequency regions are automatically analyzed for information content and quantized for subsequent Huffman encoding. Compression ratios range from 10:1 to 30:1 while maintaining the level of image quality necessary for identification. Several prototype systems were developed using SUN SPARCstation 2 with a 1280 {times} 1024 8-bit display, 64-Mbyte random access memory (RAM), Tiber distributed data interface (FDDI), and Spirit-30 S-Bus DSP-accelerators from Sonitech. The final implementation of the DSP-accelerated algorithm performed the compression or decompression operation in 3.5 s per print. Further increases in system throughput were obtained by adding several DSP accelerators operating in parallel.

  12. Influence of Rectal Decompression on Abdominal Symptoms and Anorectal Physiology following Colonoscopy in Healthy Adults

    PubMed Central

    Yi, Chih-Hsun; Liu, Tso-Tsai; Lei, Wei-Yi; Hung, Jui-Sheng

    2016-01-01

    Background. Postcolonoscopy abdominal discomfort and bloating are common. The aim of this study was to evaluate whether rectal decompression improved distension-induced abdominal symptoms and influenced anorectal physiology. Methods. In 15 healthy subjects, rectal distension was achieved by direct air inflation into the rectum by colonoscopy. Placement of rectal and sham tube was then performed in each subject on a separate occasion. The anorectal parameters and distension-induced abdominal symptoms were recorded. Results. Anorectal parameters were similar between placements of rectal tube and sham tube except for greater rectal compliance with rectal tube than with sham tube (P < 0.05). Abdominal pain and bloating were significantly reduced by rectal tube and sham tube at 1 minute (both P < 0.05) and 3 minutes (both P < 0.05). After placement of rectal tube, abdominal pain at 3 minutes correlated positively with first sensation (r = 0.53, P = 0.04), and bloating at 3 minutes also correlated positively with urge sensation (r = 0.55, P = 0.03). Conclusions. Rectal decompression with either rectal or sham tube improved distension-induced abdominal symptoms. Our study indicates that the mechanisms that improved abdominal symptoms by rectal decompression might be mediated by a central pathway instead of a peripheral mechanism. PMID:27651788

  13. Minimally invasive posterior cervical decompression using tubular retractor: The technical note and early clinical outcome

    PubMed Central

    Hur, Jung-Woo; Kim, Jin-Sung; Shin, Myeong-Hoon; Ryu, Kyeong-Sik

    2014-01-01

    Background: The aim of this work is to present a novel decompression technique that approaches cervical spine posteriorly, but through minimal invasive method using tubular retractor avoiding detachment of posterior musculature. Methods: Six patients underwent minimally invasive posterior cervical decompression using the tubular retractor system and surgical microscope. Minimally invasive access to the posterior cervical spine was performed with exposure through a paramedian muscle-splitting approach. With the assistance of a specialized tubular retraction system and deep soft tissue expansion mechanism, multilevel posterior cervical decompression could be accomplished. This approach also allows safe docking of the retractor system on the lateral mass, thus avoiding the cervical spinal canal during exposure. A standard operating microscope was used with ×10 magnification and 400 mm focal length. The hospital charts, magnetic resonance imaging studies, and follow-up records of all the patients were reviewed. Outcome was assessed by neurological status and visual analog scale (VAS) for neck and arm pain. Results: There was no significant complication related to operation. The follow-up time was 4-12 months (mean, 9 months). Muscle weakness improved in all patients; sensory deficits resolved in four patients and improved in two patients. Analysis of the mean VAS for radicular pain and VAS for neck pain showed significant improvement. Conclusions: The preliminary experiences with good clinical outcome seem to promise that this minimally invasive technique is a valid alternative option for the treatment of cervical spondylotic myelopathy. PMID:24778922

  14. Decompressive craniectomy in severe traumatic brain injury: prognostic factors and complications

    PubMed Central

    Grille, Pedro; Tommasino, Nicolas

    2015-01-01

    Objective To analyze the clinical characteristics, complications and factors associated with the prognosis of severe traumatic brain injury among patients who undergo a decompressive craniectomy. Methods Retrospective study of patients seen in an intensive care unit with severe traumatic brain injury in whom a decompressive craniectomy was performed between the years 2003 and 2012. Patients were followed until their discharge from the intensive care unit. Their clinical-tomographic characteristics, complications, and factors associated with prognosis (univariate and multivariate analysis) were analyzed. Results A total of 64 patients were studied. Primary and lateral decompressive craniectomies were performed for the majority of patients. A high incidence of complications was found (78% neurological and 52% nonneurological). A total of 42 patients (66%) presented poor outcomes, and 22 (34%) had good neurological outcomes. Of the patients who survived, 61% had good neurological outcomes. In the univariate analysis, the factors significantly associated with poor neurological outcome were postdecompressive craniectomy intracranial hypertension, greater severity and worse neurological state at admission. In the multivariate analysis, only postcraniectomy intracranial hypertension was significantly associated with a poor outcome. Conclusion This study involved a very severe and difficult to manage group of patients with high morbimortality. Intracranial hypertension was a main factor of poor outcome in this population. PMID:26340150

  15. Ambulation During Periods of Supersaturation Increase Decompression Stress in Spacewalk Simulations

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Musculoskeletal activity accelerates inert gas elimination during oxygen breathing prior to decompression (prebreathe), but may also promote bubble formation (nucleation) and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity and the level of tissue supersaturation are likely critical to the net effect. Understanding the relationships is important to evaluate exercise prebreathe protocols and quantify decompression risk in gravity and microgravity environments. The NASA Prebreathe Reduction Program (PRP) combined oxygen prebreathe and exercise preceding a low pressure (4.3 psia; altitude equivalent of 30,300 ft [9,235 m]) simulation exposure of non-ambulatory subjects (a microgravity analog) to produce two protocols now used by astronauts preparing for extravehicular activity. One protocol included both upright cycling and non-cycling exercise (CEVIS: 'cycle ergometer vibration isolation system') and one protocol relied on non-cycling exercise only (ISLE: 'in-suit light exercise'). CEVIS trial data serve as control data for the current study to investigate the influence of ambulation exercise in 1G environments on bubble formation and the subsequent risk of DCS.

  16. “Slalom”: Microsurgical Cross-Over Decompression for Multilevel Degenerative Lumbar Stenosis

    PubMed Central

    2016-01-01

    Objective. Selective, bilateral multisegmental microsurgical decompression of lumbar spinal canal stenosis through separate, alternating cross-over approaches. Indications. Two-segmental and multisegmental degenerative central and lateral lumbar spinal stenosis. Contraindications. None. Surgical Technique. Minimally invasive, muscle, and facet joint-sparing bilateral decompression of the lumbar spinal canal through 2 or more alternating microsurgical cross-over approaches from one side. Results. From December 2010 until December 2015 we operated on 202 patients with 2 or multisegmental stenosis (115 f; 87 m; average age 69.3 yrs, range 51–91 yrs). All patients were suffering from symptoms typical of a degenerative lumbar spinal stenosis. All patients complained about back pain; however the leg symptoms were dominant in all cases. Per decompressed segment, the average OR time was 36 min and the blood loss 45.7 cc. Patients were mobilized 6 hrs postop and hospitalization averaged 5.9 days. A total of 116/202 patients did not need submuscular drainage. 27/202 patients suffered from a complication (13.4%). Dural tears occurred in 3.5%, an epidural hematoma in 5.5%, a deep wound infection in 1.98%, and a temporary radiculopathy postop in 1.5%. Postop follow-up ranged from 12 to 24 months. There was a significant improvement of EQ 5 D, Oswestry Disability Index (ODI), VAS for Back and Leg Pain, and preoperative standing times and walking distances. PMID:27504456

  17. Generalized IRT Models for Extreme Response Style

    ERIC Educational Resources Information Center

    Jin, Kuan-Yu; Wang, Wen-Chung

    2014-01-01

    Extreme response style (ERS) is a systematic tendency for a person to endorse extreme options (e.g., strongly disagree, strongly agree) on Likert-type or rating-scale items. In this study, we develop a new class of item response theory (IRT) models to account for ERS so that the target latent trait is free from the response style and the tendency…

  18. [Extreme results in electrolyte determination].

    PubMed

    Vogt, W; Oesterle, B

    1992-01-01

    Besides statistical quality control, quality control based on patient specimens is an important tool for quality enhancement and thus for an increased diagnostic certainty in laboratory medicine. One of three possibilities of plausibility judgement is the control of extreme results, that is alert and absurd value check. The aim of our study was to look for extremely high or low findings of the most frequently examined clinical-chemical parameters, to scrutinize their validity according to clearly defined criteria and to find out the underlying actual clinical situations and diseases. In this publication only the results for the electrolytes are discussed. Retrospectively the most extreme values of all results for serum sodium, potassium and chloride concentrations of a 21-month interval were extracted in a large university hospital. The clinical situation was then evaluated by reading the medical reports of these patients. The validity of the findings was judged by previously defined criteria and rated as confirmed, questionable and not confirmed. In all cases the survival time was determined. The most extreme confirmed results were for sodium 191 and 100 mmol/l, for potassium 9.0 and 1.3 mmol/l and for chloride 138 and 65 mmol/l. All these findings were compatible with life, at least for several hours. Even if it is probably impossible to give generally valid extreme ranges. Nevertheless our results should certainly have practical importance in absurd and alert value check. PMID:1502820

  19. Gas evolution in eruptive conduits: Combining insights from high temperature and pressure decompression experiments with steady-state flow modeling

    USGS Publications Warehouse

    Mangan, M.; Mastin, L.; Sisson, T.

    2004-01-01

    In this paper we examine the consequences of bubble nucleation mechanism on eruptive degassing of rhyolite magma. We use the results of published high temperature and pressure decompression experiments as input to a modified version of CONFLOW, the numerical model of Mastin and Ghiorso [(2000) U.S.G.S. Open-File Rep. 00-209, 53 pp.] and Mastin [(2002) Geochem. Geophys. Geosyst. 3, 10.1029/2001GC000192] for steady, two-phase flow in vertical conduits. Synthesis of the available experimental data shows that heterogeneous nucleation is triggered at ??P 120-150 MPa, and leads to disequilibrium degassing at extreme H2O supersaturation. In this latter case, nucleation is an ongoing process controlled by changing supersaturation conditions. Exponential bubble size distributions are often produced with number densities of 106-109 bubbles/cm3. Our numerical analysis adopts an end-member approach that specifically compares equilibrium degassing with delayed, disequilibrium degassing characteristic of homogeneously-nucleating systems. The disequilibrium simulations show that delaying nucleation until ??P =150 MPa restricts degassing to within ???1500 m of the surface. Fragmentation occurs at similar porosity in both the disequilibrium and equilibrium modes (???80 vol%), but at the distinct depths of ???500 m and ???2300 m, respectively. The vesiculation delay leads to higher pressures at equivalent depths in the conduit, and the mass flux and exit pressure are each higher by a factor of ???2.0. Residual water contents in the melt reaching the vent are between 0.5 and 1.0 wt%, roughly twice that of the equilibrium model. ?? 2003 Elsevier B.V. All rights reserved.

  20. Surgical decompression in endocrine orbitopathy. Visual evoked potential evaluation and effect on the optic nerve.

    PubMed

    Clauser, Luigi C; Tieghi, Riccardo; Galie', Manlio; Franco, Filippo; Carinci, Francesco

    2012-10-01

    Endocrine orbitopathy (EO) represents the most frequent and important extrathyroidal stigma of Graves disease. This chronic autoimmune condition involves the orbital contents, including extraocular muscles, periorbital connective-fatty tissue and lacrimal gland. The increase of fat tissue and the enlargement of extraocular muscles within the bony confines of the orbit leads to proptosis, and in the most severe cases optic neuropathy, caused by compression and stretching of the optic nerve. The congestion and the pressure of the enlarged muscles, constrict the nerve and can lead to reduced sight or loss of vision with the so called "orbital apex syndrome". Generally surgical treatmen