Six-Degree Head-Down Tilt Bed Rest: Forty Years of Development as a Physiological Analog for Weightlessness

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Smith, Jeffrey D.; Cromwell, Ronita L.; Kundrot, Craig E.; Charles, John B.

2011-01-01

Early on, bed rest was recognized as a method for inducing many of the physiological changes experienced by spaceflight. Head-down tilt (HDT) bed rest was first introduced as an analog for spaceflight by a Soviet team led by Genin and Kakurin. Their study was performed in 1970 (at -4 degrees) and lasted for 30 days; results were reported in the Russian Journal of Space Biology (Kosmicheskaya Biol. 1972; 6(4): 26-28 & 45-109). The goal was to test physiological countermeasures for cosmonauts who would soon begin month-long missions to the Salyut space station. HDT was chosen to produce a similar sensation of blood flow to the head reported by Soyuz cosmonauts. Over the next decade, other tilt angles were studied and comparisons with spaceflight were made, showing that HDT greater than 4 degrees was superior to horizontal bed rest for modeling acute physiological changes observed in space; but, at higher angles, subjects experienced greater discomfort without clearly improving the physiological comparison to spaceflight. A joint study performed by US and Soviet investigators, in 1979, set the goal of standardization of baseline conditions and chose 6-degrees HDT. This effectively established 6-degree HDT bed rest as the internationally-preferred analog for weightlessness and, since 1990, nearly all further studies have been conducted at 6-degrees HDT. A thorough literature review (1970-2010) revealed 534 primary scientific journal articles which reported results from using HDT as a physiological analog for spaceflight. These studies have ranged from as little as 10 minutes to the longest duration of 370 days. Long-term studies lasting four weeks or more have resulted in over 170 primary research articles. Today, the 6-degree HDT model provides a consistent, thoroughly-tested, ground-based analog for spaceflight and allows the proper scientific controls for rigorous testing of physiological countermeasures; however, all models have their strengths and limits. The 6

Executive function on the 16-day of bed rest in young healthy men

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Ishizaki, Yuko; Fukuoka, Hideoki; Tanaka, Hidetaka; Ishizaki, Tatsuro; Fujii, Yuri; Hattori-Uchida, Yuko; Nakamura, Minako; Ohkawa, Kaoru; Kobayashi, Hodaka; Taniuchi, Shoichiro; Kaneko, Kazunari

2009-05-01

Microgravity due to prolonged bed rest may cause changes in cerebral circulation, which is related to brain function. We evaluate the effect of simulated microgravity due to a 6° head-down tilt bed rest experiment on executive function among 12 healthy young men. Four kinds of psychoneurological tests—the table tapping test, the trail making test, the pointing test and losing at rock-paper-scissors—were performed on the baseline and on day 16 of the experiment. There was no significant difference in the results between the baseline and day 16 on all tests, which indicated that executive function was not impaired by the 16-day 6° head-down tilting bed rest. However, we cannot conclude that microgravity did not affect executive function because of the possible contribution of the following factors: (1) the timing of tests, (2) the learning effect, or (3) changes in psychophysiology that were too small to affect higher brain function.

Effects of long-term head-down-tilt bed rest and different training regimes on the coagulation system of healthy men.

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Haider, Thomas; Gunga, Hanns-Christian; Matteucci-Gothe, Raffaella; Sottara, Elke; Griesmacher, Andrea; Belavý, Daniel L; Felsenberg, Dieter; Werner, Andreas; Schobersberger, Wolfgang

2013-11-01

Immobility plus preexisting chronic disease or acute trauma can activate the coagulation system, thus increasing the risk for thromboembolic events. The effects of long-term bed-rest immobility and microgravity on the coagulation system of healthy persons (e.g., during crewed Mars missions) have not yet been studied. The main objective of the second Berlin BedRest Study (BBR2-2) "Coagulation Part" was to investigate adaptations of the hemostatic system during long-term bed rest (60 days) under simulated microgravity (6° head-down-tilt [6°HDT]) and after mobilization in three different volunteer groups (randomly assigned to CTR= inactive control group; RE= resistive exercise only group; and RVE= resistive exercise with whole-body vibration group). In 24 males (aged 21-45 years), before, during, and after long-term bed rest, key parameters of coagulation were measured from venous blood samples: D-dimer (DD), thrombin-antithrombin III complex (TAT), and prothrombin fragment F1 + 2 (PT-F1 + 2). Additionally, modified rotational thrombelastometry (ROTEM (®) ) analysis was performed. Times of exploratory analyses were as follows: baseline data collection 2 days before bed rest (BDC-2); eight different days of 6°HDT bed rest (HDT1-HDT60), and two different days after reambulation (R + 3 and R + 6). We found significant changes in DD, TAT, and PT-F1 + 2 over the total time course, but no consistent effect of physical interventions (RE, RVE) on these parameters. Notably, no parameter reached levels indicative of intravascular thrombin formation. All ROTEM® parameters remained within the normal range and no pathological traces were found. Sixty days of 6°HDT bed rest are not associated with pronounced activation of the coagulation system indicative of intravascular thrombus formation in healthy volunteers independent of the training type during the bed rest.

Increased Brain Activation for Foot Movement During 70-Day 6 Deg Head-Down Bed Rest (HDBR): Evidence from Functional Magnetic Resonance Imaging (fMRI)

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Yuan, P.; Koppelmans, V.; Cassady, K.; Cooke, K.; De Dios, Y. E.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S. J.; Reuter-Lorenz, P. A.;

Long Duration Head Down Tilt Bed Rest and Spaceflight Effects on Neurocognitive Performance: Extent, Longevity and Neural Bases

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Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Cassady, K.; Yuan, P.; Kofman, I. S.; De Dios, Y. E.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

2017-01-01

We have recently completed a long duration head down tilt bed rest (HDBR) study in which we performed structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations in a spaceflight analog environment. We are also collecting the same measures in crewmembers prior to and following a six month International Space Station mission. We will present data demonstrating that bed rest resulted in functional mobility and balance deterioration with recovery post-HDBR. We observed numerous changes in brain structure, function, and connectivity relative to a control group which were associated with pre to post bed rest changes in sensorimotor function. For example, gray matter volume (GMv) increased in posterior parietal areas and decreased in frontal regions. GMv increases largely overlapped with fluid decreases and vice versa. Larger increases in precentral gyrus (M1)/ postcentral gyrus (S1+2) GMv and fluid decreases were associated with smaller balance decrements. Vestibular activation in the bilateral insular cortex increased with bed rest and subsequently recovered. Larger increases in vestibular activation in multiple brain regions were associated with greater decrements in balance and mobility. We found connectivity increases between left M1 with right S1+2 and the superior parietal lobule, and right vestibular cortex with the cerebellum. Decreases were observed between right Lobule VIII with right S1+2 and the supramarginal gyrus, right posterior parietal cortex (PPC) with occipital regions, and the right superior posterior fissure with right Crus I and II. Connectivity strength between left M1 and right S1+2/superior parietal lobule increased the most in individuals that exhibited the least balance impairments. In sum, we observed HDBR-related changes in measures of brain structure, function, and network connectivity, which correlated with indices of sensorimotor

The Effects of Long Duration Bed Rest on Brain Functional Connectivity and Sensorimotor Functioning

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Cassady, K.; Koppelmans, V.; De Dios, Y.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S.; Reuter-Lorenz, P.; Castenada, R. Riascos; Kofman, I.;

Bone Resorption Increases as Early as the Second Day in Head- Down Bed Rest

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Heer, M.; Kamps, N.; Mika, C.; Boese, A.; Gerzer, R.

Long-term bed rest and space mission studies have shown that immobilization as well as microgravity induce increased bone resorption while bone formation tends to decrease. In order to analyze the kinetics of short-term changes in bone turnover we studied in a randomized, strictly controlled crossover design the effects of 6 days 6° head-down tilt bed rest (HDT) in 8 male healthy subjects (mean body weight (BW): 70.1 +/- 1.88 kg; mean age: 25.5 +/- 1.04 years) in our metabolic ward. Two days before arriving in the metabolic ward the subjects started with a diet consisting of an energy content of 10 MJ/d, 2000 mg Calcium/d, 400 i.U. Vitamin D, 200 mEq Na+ and 50 ml water/kg BW/d. The diet was continued in the metabolic ward. The metabolic ward period (11days) was divided into 3 parts: 4 ambulatory days, 6 days either HDT or control and 1 recovery day. Continuous urine collection started on the first day in the metabolic ward to analyze calcium excretion and bone resorption markers, namely C-telopeptide (CTX) and N-telopeptide (NTX). On the 2nd ambulatory day in the metabolic ward and on the 5th day in HDT or control blood was drawn to analyze serum calcium, parathyroid hormone, and bone formation markers (bone Alkaline Phosphatase (bAP), Procollagen-I-Propeptide (P-I-CP). Both study phases were identical with respect to environmental conditions, study protocol and diet. Urinary calcium excretion was as early as the first day in immobilization increased (pcontrol. But, already on the 2nd day of immobilization both bone resorption markers significantly increased. NTX-excretion was increased by 28.7 +/- 14.0% (pcontrol. In contrast to the bone resorption markers, the formation marker P-I-CP tended to decrease as early as the fifth day of immobilization (phormone-, as well as bAP concentrations were unchanged. We conclude from these results of a pronounced rise of bone resorption markers that already 24 hours of immobilization induce a significant rise in osteoclast

Orthostatic Intolerance Is Independent of the Degree of Autonomic Cardiovascular Adaptation after 60 Days of Head-Down Bed Rest

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Aubert, André E.

2015-01-01

Spaceflight and head-down bed rest (HDBR) can induce the orthostatic intolerance (OI); the mechanisms remain to be clarified. The aim of this study was to determine whether or not OI after HDBR relates to the degree of autonomic cardiovascular adaptation. Fourteen volunteers were enrolled for 60 days of HDBR. A head-up tilt test (HUTT) was performed before and after HDBR. Our data revealed that, in all nonfainters, there was a progressive increase in heart rate over the course of HDBR, which remained higher until 12 days of recovery. The mean arterial pressure gradually increased until day 56 of HDBR and returned to baseline after 12 days of recovery. Respiratory sinus arrhythmia and baroreflex sensitivity decreased during HDBR and remained suppressed until 12 days of recovery. Low-frequency power of systolic arterial pressure increased during HDBR and remained elevated during recovery. Three subjects fainted during the HUTT after HDBR, in which systemic vascular resistance did not increase and remained lower until syncope. None of the circulatory patterns significantly differed between the fainters and the nonfainters at any time point. In conclusion, our data indicate that the impaired orthostatic tolerance after HDBR could not be distinguished by estimation of normal hemodynamic and/or neurocardiac data. PMID:26425559

Orthostatic Intolerance Is Independent of the Degree of Autonomic Cardiovascular Adaptation after 60 Days of Head-Down Bed Rest

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Jiexin Liu

2015-01-01

Full Text Available Spaceflight and head-down bed rest (HDBR can induce the orthostatic intolerance (OI; the mechanisms remain to be clarified. The aim of this study was to determine whether or not OI after HDBR relates to the degree of autonomic cardiovascular adaptation. Fourteen volunteers were enrolled for 60 days of HDBR. A head-up tilt test (HUTT was performed before and after HDBR. Our data revealed that, in all nonfainters, there was a progressive increase in heart rate over the course of HDBR, which remained higher until 12 days of recovery. The mean arterial pressure gradually increased until day 56 of HDBR and returned to baseline after 12 days of recovery. Respiratory sinus arrhythmia and baroreflex sensitivity decreased during HDBR and remained suppressed until 12 days of recovery. Low-frequency power of systolic arterial pressure increased during HDBR and remained elevated during recovery. Three subjects fainted during the HUTT after HDBR, in which systemic vascular resistance did not increase and remained lower until syncope. None of the circulatory patterns significantly differed between the fainters and the nonfainters at any time point. In conclusion, our data indicate that the impaired orthostatic tolerance after HDBR could not be distinguished by estimation of normal hemodynamic and/or neurocardiac data.

Evaluation of T-wave alternans activity under stress conditions after 5 d and 21 d of sedentary head-down bed rest

International Nuclear Information System (INIS)

Martín-Yebra, A; Caiani, E G; Pellegrini, A; Monasterio, V; Laguna, P; Martínez, J P

2015-01-01

It is well known that prolonged microgravity leads to cardiovascular deconditioning, inducing significant changes in autonomic control of the cardiovascular system. This may adversely influence cardiac repolarization, and provoke cardiac rhythm disturbances. T-wave alternans (TWA), reflecting temporal and spatial repolarization heterogeneity, could be affected. The aim of this work was to test the hypothesis that 5 d and 21 d head-down (−6°) bed rest (HDBR) increases TWA, thus suggesting a higher underlying electrical instability and related arrhythmogenic risk.Forty-four healthy male volunteers were enrolled in the experiments as part of the European Space Agency’s HDBR studies. High-fidelity ECG was recorded during orthostatic tolerance (OT) and aerobic power (AP) tests, before (PRE) and after HDBR (POST). A multilead scheme for TWA amplitude estimation was used, where non-normalized and T-wave amplitude normalized TWA indices were computed. In addition, spectral analysis of heart rate variability during OT was assessed.Both 5 d and 21 d HDBR induced a reduction in orthostatic tolerance time (OTT), as well as a decrease in maximal oxygen uptake and reserve capacity, thus suggesting cardiovascular deconditioning. However, TWA indices were found not to increase. Interestingly, subjects with lower OTT after 5 d HDBR also showed higher TWA during recovery after OT testing, associated with unbalanced sympathovagal response, even before the HDBR. In contrast with previous observations, augmented ventricular heterogeneity related to 5 d and 21 d HDBR was not sufficient to increase TWA under stress conditions. (paper)

Effects of strict prolonged bed rest on cardiorespiratory fitness

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Ried-Larsen, Mathias; Aarts, Hugo M; Joyner, Michael J

2017-01-01

The aim of this systematic review and meta-analysis [International Prospective Register of Systematic Reviews (PROSPERO) CRD42017055619] was to assess the effects of strict prolonged bed rest (without countermeasures) on maximal oxygen uptake (V̇o2max) and to explore sources of variation therein....

Effect of 21-day head down bed rest on urine proteins related to endothelium: Correlations with changes in carbohydrate metabolism

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Kashirina, D.; Pastushkova, L.; Custaud, M. A.; Dobrokhotov, I.; Brzhozovsky, A.; Navasiolava, N.; Nosovsky, A.; Kononikhin, A.; Nikolaev, E.; Larina, I.

2017-08-01

We performed liquid chromatography-mass spectrometric study of the urine proteome in 8 healthy volunteers aged between 20 and 44 y.o. who have completed 21-day head-down bed rest. ANDSystem software which builds associative networks was used to identify the urinary proteins functionally related to the endothelium. We identified 7 endothelium-related biological processes, directly linked to 13 urine proteins. We performed manual annotation of the proteins which were the most important in terms of endothelial functions. Analysis of the correlations with biochemical variables revealed a positive correlation between fasting blood glucose and the following urine proteins: albumin, CD44 antigen, endothelial protein C receptor, mucin-1, osteopontin, receptor tyrosine kinase. As well, we found a positive correlation between HOMA-insulin resistance index and the following urine proteins: endothelial protein C receptor and syndecan-4. These results might suggest the involvement of above-mentioned proteins in glucose metabolism and their participation in the response to changes in blood glucose level.

Changes in the levels of mannan-binding lectin and ficolins during head-down tilted bed rest.

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Kelsen, Jens; Sandahl, Thomas D; Storm, Line; Frings-Meuthen, Petra; Dahlerup, Jens F; Thiel, Steffen

2014-08-01

Spaceflight studies and ground-based analogues of microgravity indicate a weakening of human immunity. Mannan-binding lectin (MBL) and H-, L-, and M-ficolin together constitute the lectin pathway and mediate the clearance of pathogens through complement activation. We hypothesized that simulated microgravity may weaken human innate immune functions and studied the impact of 6° head-down tilted bed rest (HDT) for 21 d on MBL and ficolin levels. Within a 6-mo period, seven men underwent two periods of HDT. Blood samples were analyzed for MBL, H-, L-, and M-ficolin, mannose-binding lectin-associated protein of 44 kDa (MAp44), and collectin liver 1 (CL-L1) by time-resolved immunofluorometric assays (TRIFMA). We observed well-defined individual preintervention levels of MBL and ficolins. Remarkably similar intraindividual changes occurred for MBL and MBL levels decreased (mean 282 ng · ml⁻¹) in the recovery phase. Conversely, CL-L1, a protein with MBL-like properties, increased (mean 102 ng · ml⁻¹) during the recovery phase. M-ficolin increased (mean 79 ng · ml⁻¹) within the first 2 d of HDT, followed by a decrease (mean 112 ng · ml⁻¹) during the recovery phase. L-ficolin increased (mean 304 ng · ml⁻¹) during HDT, while H-ficolin was essentially unaffected. MAp44, a down-regulator of the lectin pathway, decreased initially (mean 78 ng · ml⁻¹) in the recovery phase followed by an increase (mean 131 ng · ml⁻¹). Alterations in MBL and ficolin levels were modest and with our current knowledge do not lead to overt immunodeficiency. Pronounced changes occurred when the subjects resumed the upright position. In selected individuals, these changes appear to be a conserved response to HDT.

CHANGES IN MENTAL HEALTH AND SATISFACTION WITH LIFE DURING PHYSICAL INACTIVITY INDUCED BY BED REST EXPERIMENT

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Tjaša Dimec Časar

2016-01-01

Full Text Available Simulated weightlessness by bed rest model represents an important method to study the consequences of physical inactivity and sedentarism on the human body. The purpose of the study was to examine the effects of prolonged physical inactivity on psychological distress, depressive symptoms and satisfaction with life of healthy male adults. Participants were ten volunteers, aged between 21 and 28 years who were subjected to a 35-day head-down bed rest. Psychological state of the participants was measured with the General Health Questionnaire (GHQ-12, the Center for Epidemiological Studies Depression Scale (CES-D, and the Satisfaction with Life Scale (SWLS. Participants completed psychological inventories before, during and after the experiment. The results revealed no significant differences in mental health and satisfaction with life of participants following the head-down bed rest, however there was a tendency towards an increase in neurotic and depressive symptoms at the end of the experiment. The obtained results are interpreted in the light of stimulative living conditions in which the experiment was carried out, as well as the amount and quality of social interactions during the period of extended physical inactivity.

Focal Gray Matter Plasticity as a Function of Long Duration Head Down Tilted Bed Rest: Preliminary Results

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Koppelmans, V.; Erdeniz, B.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Seidler, R. D.

2014-01-01

Long duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes are solely related to peripheral changes from reduced vestibular stimulation, body unloading, body fluid shifts or that they may be related to structural and functional brain changes is yet unknown. However, a recent study reported associations between microgravity and flattening of the posterior eye globe and protrusion of the optic nerve [1] possibly as the result of increased intracranial pressure due to microgravity induced bodily fluid shifts [3]. Moreover, elevated intracranial pressure has been related to white matter microstructural damage [2]. Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning. Long duration head down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system [4]. Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on brain structure [5]. Here we present results of the first six subjects. Six subjects were assessed at 12 and 7 days before-, at 7, 30, and 70 days in-, and at 8 and 12 days post 70 days of bed rest at the NASA bed rest facility in UTMB, Galveston, TX, USA. At each time point structural MRI scans (i.e., high resolution T1-weighted imaging and Diffusion Tensor Imaging (DTI)) were obtained using a 3T Siemens scanner. Focal changes over time in gray matter density were assessed using the voxel based morphometry 8 (VBM8) toolbox under SPM

Analysis of Arterial Mechanics During Head-Down-Tilt Bed Rest

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Elliott, Morgan B.; Martin, David S.; Westby, Christian M.; Stenger, Michael B.; Platts, Steven H.

2014-01-01

Carotid, brachial, and tibial arteries reacted differently to HDTBR. Previous studies have not analyzed the mechanical properties of the human brachial or anterior tibial arteries. After slight variations during bed-rest, arterial mechanical properties and IMT returned to pre-bed rest values, with the exception of tibial stiffness and PSE, which continued to be reduced post-bed rest while the DC remained elevated. The tibial artery remodeling was probably due to decreased pressure and volume. Resulting implications for longer duration spaceflight are unclear. Arterial health may be affected by microgravity, as shown by increased thoracic aorta stiffness in other ground based simulations (Aubert).

Association Between Cardiovascular and Intraocular Pressure Changes in a 14-Day 6 deg Head Down Tilt (HDT) Bed Rest Study: Possible Implications in Retinal Anatomy

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Cromwell, Ronita; Zanello, Susana; Yarbough, Patrice; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco

2013-01-01

Visual symptoms and intracranial pressure increase reported in astronauts returning from long duration missions in low Earth-orbit are thought to be related to fluid shifts within the body due to microgravity exposure. Because of this possible relation to fluid shifts, studies conducted in head-down tilt (HDT) bed rest are being monitored for potential changes in ocular health. These measures will also serve to determine whether HDT is a suitable ground-based analog to model subclinical cardiovascular and ocular changes that could shed light on the etiology of the VIIP syndrome observed in spaceflight. Sixteen healthy normotensive (12M, 4F, age range 29-54 years), non-smoker and normal weight subjects, volunteered to participate in a 14 day 6 deg head HDT study conducted at the NASA Flight Analogs Research Unit (FARU). This facility provides standard bed rest conditions (diet, wake/sleep time, time allowed in sunlight) during the time that the subjects stay at the FARU. Cardiovascular parameters were obtained in supine posture at BR-5, BR+0, and BR+3 and ocular monitoring was performed weekly. Intraocular pressure (IOP) increased from pre-bed rest BR-3) to the third day into bed rest (BR+3). Values reached a plateau towards the end of the bed rest phase (BR10) and decreased within the first three days of recovery (BR+2) returning to levels comparable to baseline at BR-3. As expected, most cardiovascular parameters were affected by 14 days of HDT bed rest. Plasma volume decreased as a result of bed rest but recovered to baseline levels by BR+3. Indications of cardiovascular deconditioning included increase in both systolic and diastolic blood pressure and heart rate, and a decrease in stroke volume and cardiac output between BR-5 and BR+3. Due to the experimental design of this study, we were not able to test the hypothesis that fluid shifts might be involved in the IOP increase during the bed rest phase, since cardiovascular measures were not available for those

Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity.

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van Oosterhout, W P J; Terwindt, G M; Vein, A A; Ferrari, M D

2015-04-01

Headache is a common symptom during space travel, both isolated and as part of space motion syndrome. Head-down-tilted bed rest (HDTBR) studies are used to simulate outer space microgravity on Earth, and allow countermeasure interventions such as artificial gravity and training protocols, aimed at restoring microgravity-induced physiological changes. The objectives of this article are to assess headache incidence and characteristics during HDTBR, and to evaluate the effects of countermeasures. In a randomized cross-over design by the European Space Agency (ESA), 22 healthy male subjects, without primary headache history, underwent three periods of -6-degree HDTBR. In two of these episodes countermeasure protocols were added, with either centrifugation or aerobic exercise training protocols. Headache occurrence and characteristics were daily assessed using a specially designed questionnaire. In total 14/22 (63.6%) subjects reported a headache during ≥1 of the three HDTBR periods, in 12/14 (85.7%) non-specific, and two of 14 (14.4%) migraine. The occurrence of headache did not differ between HDTBR with and without countermeasures: 12/22 (54.5%) subjects vs. eight of 22 (36.4%) subjects; p = 0.20; 13/109 (11.9%) headache days vs. 36/213 (16.9%) headache days; p = 0.24). During countermeasures headaches were, however, more often mild (p = 0.03) and had fewer associated symptoms (p = 0.008). Simulated microgravity during HDTBR induces headache episodes, mostly on the first day. Countermeasures are useful in reducing headache severity and associated symptoms. Reversible, microgravity-induced cephalic fluid shift may cause headache, also on Earth. HDTBR can be used to study space headache on Earth. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Petechiae: reproducible pattern of distribution and increased appearance after bed rest.

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Ganse, Bergita; Limper, Ulrich; Bühlmeier, Judith; Rittweger, Jörn

2013-08-01

Exposure to acceleration can cause petechial hemorrhages, called G measles. Petechiae usually start to develop between 5 and 9 G with a high interindividual variance. Centrifuge training delays the onset to higher G levels. One might expect onset at lower G levels after bed rest; however, there is no evidence in the literature. A case of petechiae formation after bed rest is presented here. Orthostatic tolerance was tested using a tilt table and lower body negative pressure before and after bed rest in both campaigns of a 2 x 21-d bed rest study with 6 degrees head-down tilt. A 42-yr-old male Caucasian without any history of thrombosis, venous disease, hemorrhage, or petechiae, and with a negative thrombophilia screening, took part in the bed rest study as 1 out of 10 subjects. He was the only one to develop petechiae during the orthostatic tests after, but not before, bed rest in both campaigns. Petechiae were distributed throughout the lower legs and most pronounced at the shin in a stocking-like fashion, surprisingly reoccurring in an identical pattern of distribution. Petechiae appeared slowly over minutes during hyperemia. This case indicates that prolonged bed rest decreases the threshold for petechiae formation. A reproducible distribution pattern suggests that factors predisposing to petechiae formation keep their local distribution over time (possibly due to local vessel structures). Mechanisms of adaptation and interindividual variance are unclear. Findings are of clinical relevance as such cases might occur after prolonged bed rest in patients without need of expensive testing.

Calf tissue liquid stowage and muscular and deep vein distension in orthostatic tests after a 90-day head down bed rest

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Arbeille, P.A.; Kerbeci, P.; Audebert, P.; Capri, A.; Pascaud, L.

2005-08-01

The objectives were to assess the contribution of (1) the calf veins distension and(2) the tissue liquid stowage during standtest, to orthostatic intolerance "OI" after a head down bed rest (HDBR) of 90days. Method: The population consisted of a control group (Co-gr, n=9) and an exercise Fly wheel counter-measure group (CM-gr, n=9). Calf vein cross sectional area (CSA) and surrounding tissue liquid content (tissue image darkness) were assessed by echography during pre and post HDBR stand-tests. Results: From supine to standing (post HDBR), the Tibial and muscular vein CSA increased significantly in non tolerant subjects whereas in tolerant subjects the vein CSA did not change. Post HDBR the tissue image darkness (proportional to tissue liquid content) increased more from supine to standing in non tolerant than in tolerant subjects. No significant difference were found between Co and exercise CM groups. Conclusion: High calf vein CSA and tissue liquid content increase at post-HDBR stand-test were significantly correlated with occurrence of OI but not with CM.

Body Unloading Associated with Space Flight and Bed-rest Impacts Functional Performance

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Bloomberg, J. J.; Ballard, K. L.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Peters, B. T.;

Ultrasound measurement of transcranial distance during head-down tilt

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Torikoshi, S.; Wilson, M. H.; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Yost, W. T.; Cantrell, J. H.; Chang, D. S.; Hargens, A. R.

1995-01-01

Exposure to microgravity elevates blood pressure and flow in the head, which may increase intracranial volume (ICV) and intracranial pressure (ICP). Rhesus monkeys exposed to simulated microgravity in the form of 6 degree head-down tilt (HDT) experience elevated ICP. With humans, twenty-four hours of 6 degree HDT bed rest increases cerebral blood flow velocity relative to pre-HDT upright posture. Humans exposed to acute 6 degree HDT experiments increased ICP, measured with the tympanic membrane displacement (TMD) technique. Other studies suggest that increased ICP in humans and cats causes measurable cranial bone movement across the sagittal suture. Due to the slightly compliant nature of the cranium, elevation of the ICP will increase ICV and transcranial distance. Currently, several non-invasive approaches to monitor ICP are being investigated. Such techniques include TMD and modal analysis of the skull. TMD may not be reliable over a large range of ICP and neither method is capable of measuring the small changes in pressure. Ultrasound, however, may reliably measure small distance changes that accompany ICP fluctuations. The purpose of our study was to develop and evaluate an ultrasound technique to measure transcranial distance changes during HDT.

The Effects of Long Duration Bed Rest on Functional Mobility and Balance: Relationship to Resting State Motor Cortex Connectivity

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Erdeniz, B.; Koppelmans, V.; Bloomberg, J. J.; Kofman, I. S.; DeDios, Y. E.; Riascos-Castaneda, R. F.; Wood, S. J.; Mulavara, A. P.; Seidler, R. D.

2014-01-01

NASA offers researchers from a variety of backgrounds the opportunity to study bed rest as an experimental analog for space flight. Extended exposure to a head-down tilt position during long duration bed rest can resemble many of the effects of a low-gravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The aim of our study is to a) identify changes in brain function that occur with prolonged bed rest and characterize their recovery time course; b) assess whether and how these changes impact behavioral and neurocognitive performance. Thus far, we completed data collection from six participants that include task based and resting state fMRI. The data have been acquired through the bed rest facility located at the University of Texas Medical Branch (Galveston, TX). Subjects remained in bed with their heads tilted down 6 degrees below their feet for 70 consecutive days. Behavioral measures and neuroimaging assessments were obtained at seven time points: a) 7 and 12 days before bed rest; b) 7, 30, and 65 days during bed rest; and c) 7 and 12 days after bed rest. Functional connectivity magnetic resonance imaging (FcMRI) analysis was performed to assess the connectivity of motor cortex in and out of bed rest. We found a decrease in motor cortex connectivity with vestibular cortex and the cerebellum from pre bed rest to in bed rest. We also used a battery of behavioral measures including the functional mobility test and computerized dynamic posturography collected before and after bed rest. We will report the preliminary results of analyses relating brain and behavior changes. Furthermore, we will also report the preliminary results of a spatial working memory task and vestibular stimulation during in and out of bed rest.

Intensive Exercise Training During Bed Rest Attenuates Deconditioning

Science.gov (United States)

Greenleaf, John E.

1997-01-01

Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Effects of Resistive Vibration Exercise Combined with Whey Protein and KHCO3 on Bone Tturnover Markers in Head-down Tilt Bed Rest (MTBR-MNX Study)

Science.gov (United States)

Graf, Sonja; Baecker, Natalie; Buehlmeier, Judith; Fischer, Annelie; Smith, Scott M.; Heer, Martina

2014-01-01

High protein intake further increases bone resorption markers in head-down tilt bed rest (HDBR), most likely induced by low-grade metabolic acidosis. Adding an alkaline salt to a diet with high protein content prevents this additional rise of bone resorption markers in HDBR. In addition, high protein intake, specifically whey protein, increases muscle protein synthesis and improves glucose tolerance, which both are affected by HDBR. Resistive vibration exercise (RVE) training counteracts the inactivity-induced bone resorption during HDBR. To test the hypothesis that WP plus alkaline salt (KHCO3) together with RVE during HDBR will improve bone turnover markers, we conducted a randomized, three-campaign crossover design study with 12 healthy, moderately fit male subjects (age 34+/-8 y, body mass [BM] 70 +/- 8 kg). All study campaigns consisted of a 7-d ambulatory period, 21days of -6 deg. head-down tilt bed rest (HDBR), and a 6-d recovery period. Diet was standardized and identical across phases. In the control (CON) campaign, subjects received no supplement or RVE. In the intervention campaigns, subjects received either RVE alone or combined with WP and KHCO3 (NEX). WP was applied in 3 doses per day of 0.6 g WP/kg BM together with 6 doses of 15 mmol KHCO3 per day. Eleven subjects completed the RVE and CON campaign, 8 subjects completed all three campaigns. On day 21 of HDBR excretion of the bone resorption marker C-telopeptide (CTX) was 80+/-28% (p<0.001) higher than baseline, serum calcium concentrations increased by 12 +/- 29% (p<0.001) and serum osteocalcin concentrations decreased by 6+/-12% (p=0.001). Urinary CTX excretion was 11+/- 25% (p=0.02) lower on day 21 of HDBR in the RVE- and tended to decrease by 3+/- 22% (p=0.06) in the NEX campaign compared to CON. Urinary calcium excretion was higher on day 21 in HDBR in the RVE and NEX (24+/- 43% p=0.01; 25+/- 37% p=0.03) compared to the CON campaign. We conclude that combination of RVE with WP/KHCO3 was not

Head-up and head-down displays integration in automobiles

Science.gov (United States)

Betancur, J. Alejandro; Osorio-Gómez, Gilberto; Agudelo, J. David

2014-06-01

In automotive industry, the dashboard has been ergonomically developed in order to keep the driver focused on the horizon while driving, but the possibility to access external electronic devices constraints the driver to turn away his face, generating dangerous situations in spite of the short periods of time. Therefore, this work explores the integration of Head-Up Displays and Head-Down Displays in automobiles, proposing configurations that give to drivers the facility to driving focused. In this way, some of the main ergonomic comments about those configurations are proposed; and also, some technical comments regarding the implemented arrangements are given.

The Effects of Long Duration Head Down Tilt Bed Rest on Neurocognitive Performance: The Effects of Exercise Interventions

Science.gov (United States)

Seidler, R. D.; Mulavara, A. P.; Koppelmans, V.; Erdeniz. B.; Kofman, I. S.; DeDios, Y. E.; Szecsy, D. L.; Riascos-Castaneda, R. F.; Wood, S. J.; Bloomberg, J. J.

2014-01-01

We are conducting ongoing experiments in which we are performing structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations following a six month International Space Station mission and following 70 days exposure to a spaceflight analog, head down tilt bedrest. Our central hypothesis is that measures of brain structure, function, and network integrity will change from pre to post intervention (spaceflight, bedrest). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a neuroanatomically selective fashion. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad ranging battery of sensory, motor, and cognitive assessments that will be conducted pre flight, during flight, and post flight to investigate potential neuroplastic and maladaptive brain changes in crewmembers following long-duration spaceflight. Success in this endeavor would 1) result in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior, and 2) identify whether a return to normative behavioral function following re-adaptation to Earth's gravitational environment is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes. Our ongoing bed rest participants are also engaging in exercise studies directed by Dr. Lori Ploutz Snyder. In this presentation, I will briefly highlight the existing literature linking exercise and fitness to brain and behavioral functions. I will also overview the metrics from my study that could be investigated in relation to the exercise and control subgroups.

21 Days head-down bed rest induces weakening of cell-mediated immunity - Some spaceflight findings confirmed in a ground-based analog.

Science.gov (United States)

Kelsen, Jens; Bartels, Lars Erik; Dige, Anders; Hvas, Christian Lodberg; Frings-Meuthen, Petra; Boehme, Gisela; Thomsen, Marianne Kragh; Fenger-Grøn, Morten; Dahlerup, Jens Frederik

2012-08-01

Several studies indicate a weakening of cell-mediated immunity (CMI) and reactivation of latent herpes viruses during spaceflight. We tested the hypothesis that head-down bed rest (HDBR), a ground-based analog of spaceflight, mimics the impact of microgravity on human immunity. Seven healthy young males underwent two periods of 3 weeks HDBR in the test facility of the German Aerospace Center. As a nutritional countermeasure aimed against bone demineralisation, 90 mmol potassium bicarbonate (KHCO(3)) was administered daily in a crossover design. Blood samples were drawn on five occasions. Whole blood was stimulated with antigen i.e. Candida albicans, purified protein derivative (PPD) tuberculin, tetanus toxoid and Cytomegalovirus (CMV) (CMV-QuantiFERON). Flow cytometric analysis included CD4(+)CD25(+)CD127(-)FOXP3(+) regulatory T cells (Tregs), γδ T cells, B cells, NK cells and dendritic cells. In one of the two bed rest periods, we observed a significant decrease in production of interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following phytohemagglutinin (PHA) stimulation, with a rapid normalization being observed after HDBR. The cytokine levels showed a V-shaped pattern that led to a relativeTh2-shift in cytokine balance. Only three individuals responded to the specific T cell antigens without showing signs of an altered response during HDBR, nor did we observe reactivation of CMV or Epstein-Barr virus (EBV). Of unknown significance, dietary supplementation with KHCO(3) counteracted the decrease in IL-2 levels during HDBR, while there was no impact on other immunological parameters. We conclude that discrete alterations in CMI may be induced by HDBR in selected individuals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vestibular and Somatosensory Covergence in Postural Equilibrium Control: Insights from Spaceflight and Bed Rest Studies

Science.gov (United States)

Mulavara, A. P.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Peters, B. T.; Phillips, T.; Platts, S. H.;

Countermeasures and Functional Testing in Head-Down Tilt Bed Rest (CFT 70)

Science.gov (United States)

Cromwell, Ronita L.

2013-01-01

This 70-day bed rest campaign was comprised of 6 integrated studies and conducted at the NASA Flight Analogs Research Unit (FARU). The FARU is located at the University of Texas Medical Branch, Galveston, Texas and is a satellite unit of the Institute for Translational Sciences - Clinical Research Center. This presentation will describe the FARU, discuss the utility of the bed rest platform for use in these studies, and introduce the studies that participated in the CFT 70 bed rest campaign. Information in this presentation will serve as the background for subsequent talks from each individual study. Individual study presentations will discuss preliminary results from completed subjects. Studies included in CFT70 were: ? Physiological Factors Contributing to Post Flight Changes in Functional Performance. J. Bloomberg, NASA ? Integrated Resistance and Aerobic Training Study. L. Ploutz-Snyder, USRA ? Testosterone Supplementation as a Countermeasure Against Musculoskeletal losses during Space Exploration. R. Urban, University of Texas Medical Branch ? Effects of Retronasal Smelling, Variety and Choice on Appetite & Satiety. J. Hunter, Cornell University ? AD ASTRA: Automated Detection of Attitudes and States through Transaction Recordings Analysis. C. Miller, Smart Information Flow Technologies, LLC ? Bed Rest as a Spaceflight Analog to Study Neuro-cognitive Changes: Extent, Longevity, and Neural Bases. R. Seidler, University of Michigan

Reducing the risk of ventilator-acquired pneumonia through head of bed elevation.

Science.gov (United States)

Keeley, Libby

2007-01-01

It has been suggested that placing critically ill ventilated patients in a semirecumbent position minimizes the likelihood of nosocomial pneumonia. This pilot study explores whether the incidence of ventilator-acquired pneumonia (VAP) can be reduced by elevating the head of the bed to 45 degrees. The design is quantitative in nature, using a randomized controlled trial. The method involves adult ventilated patients being randomly assigned to one of two positions, i.e. 45 degrees raised head of bed (treatment group) or 25 degrees raised head of bed (control group). Data collection relied upon the diagnosis of clinically suspected and microbiologically confirmed pneumonia defined by the Consensus Conference on VAP. Thirty patients were included in the study--17 in the treatment group and 13 in the control group. Results showed that 29% (five) in the treatment group and 54% (seven) in the control group contracted VAP (P VAP in the patients nursed at 45 degrees. However, because of the sample size this difference did not reach statistical significance.

Gradient Compression Stockings may Prevent Recovery after Bed Rest Deconditioning

Science.gov (United States)

Stenger, Michael B.; Lee, Stuart M.; Westby, Christian M.; Willig, Michael C.; Platts, Steven H.

2011-01-01

Introduction: Astronauts continue to wear a compression garment during and immediately after landing to prevent orthostatic intolerance (OI). We recently developed a custom-fitted, 3-piece garment that consists of thigh-high stockings with biker-style shorts that provides continuous, gradient compression: 55 mmHg at the ankle that decreases to approximately 20 mmHg at the top of the leg and 15 mmHg over the abdomen. This garment has been shown to be effective in preventing symptoms of OI during a short stand test after Space Shuttle missions, but symptoms may persist for several days after a long-duration mission in some astronauts. The purpose of this study was to confirm the effectiveness of wearing these elastic, gradient compression garments during orthostatic testing after 2 weeks of 6 degree head-down tilt bed rest as a model of spaceflight and to determine whether they would impact recovery after bed rest. Methods: Eight (5 treatment, 3 control) of 16 subjects have completed this study to-date. All subjects wore the 3-piece garment from waking until tilt testing (3 h) as a simulation of the timeline for astronauts on landing day (BR+0). Control subjects removed the garment after the tilt test. Treatment subjects wore the garment for the remainder of the day and wore lower compression thigh-high only garments on the day after bed rest (BR+1). Blood pressure, heart rate, and stroke volume responses to a 15-min 80 degree head-up tilt test were determined before 2 weeks of 6 degree head-down tilt, and on BR+0 and BR+1. Plasma volume (PV) was measured before each of these test sessions. Data are mean SE. Results: Compression garments prevented signs of OI on BR+0; all subjects in both groups completed the full 15-min test. Heart rate responses to tilt were lower on BR+0 than all other test days. Control subjects demonstrated a marginal PV decrease after bed rest, but showed typical recovery the day after bed rest (BR+0: 2.32 plus or minus 0.15 L to BR+1: 2

Weightlessness and Cardiac Rhythm Disorders: Current Knowledge from Space Flight and Bed-Rest Studies

International Nuclear Information System (INIS)

Caiani, Enrico G.; Martin-Yebra, Alba; Landreani, Federica; Bolea, Juan; Laguna, Pablo; Vaïda, Pierre

2016-01-01

Isolated episodes of heart rhythm disorders have been reported during 40 years of space flight, triggering research to evaluate the risk of developing life-threatening arrhythmias induced by prolonged exposure to weightlessness. In fact, these events could compromise astronaut performance during exploratory missions, as well as pose at risk the astronaut health, due to limited options of care on board the International Space Station. Starting from original observations, this mini review will explore the latest research in this field, considering results obtained both during space flight and on Earth, the latter by simulating long-term exposure to microgravity by head-down bed rest maneuver in order to elicit cardiovascular deconditioning on normal volunteers.

Weightlessness and Cardiac Rhythm Disorders: Current Knowledge from Space Flight and Bed-Rest Studies

Energy Technology Data Exchange (ETDEWEB)

Caiani, Enrico G. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan (Italy); Martin-Yebra, Alba [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan (Italy); Instituto de Investigación en Ingeniería de Aragón (I3A), Universidad de Zaragoza, Zaragoza (Spain); Landreani, Federica [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan (Italy); Bolea, Juan; Laguna, Pablo [Instituto de Investigación en Ingeniería de Aragón (I3A), Universidad de Zaragoza, Zaragoza (Spain); Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Zaragoza (Spain); Vaïda, Pierre, E-mail: enrico.caiani@polimi.it [École Nationale Supérieure de Cognitique, Institut Polytechnique de Bordeaux, Université de Bordeaux, Bordeaux (France)

2016-08-23

Isolated episodes of heart rhythm disorders have been reported during 40 years of space flight, triggering research to evaluate the risk of developing life-threatening arrhythmias induced by prolonged exposure to weightlessness. In fact, these events could compromise astronaut performance during exploratory missions, as well as pose at risk the astronaut health, due to limited options of care on board the International Space Station. Starting from original observations, this mini review will explore the latest research in this field, considering results obtained both during space flight and on Earth, the latter by simulating long-term exposure to microgravity by head-down bed rest maneuver in order to elicit cardiovascular deconditioning on normal volunteers.

Acute effects of head-down tilt and hypoxia on modulators of fluid homeostasis

Science.gov (United States)

Whitson, P. A.; Cintron, N. M.; Pietrzyk, R. A.; Scotto, P.; Loeppky, J. A.

1994-01-01

In an effort to understand the interaction between acute postural fluid shifts and hypoxia on hormonal regulation of fluid homeostasis, the authors measured the responses to head-down tilt with and without acute exposure to normobaric hypoxia. Plasma atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP), cyclic adenosine monophosphate (cAMP), plasma aldosterone (ALD), and plasma renin activity (PRA) were measured in six healthy male volunteers who were exposed to a head-down tilt protocol during normoxia and hypoxia. The tilt protocol consisted of a 17 degrees head-up phase (30 minutes), a 28 degrees head-down phase (1 hour), and a 17 degrees head-up recovery period (2 hours, with the last hour normoxic in both experiments). Altitude equivalent to 14,828 ft was simulated by having the subjects breathe an inspired gas mixture with 13.9% oxygen. The results indicate that the postural fluid redistribution associated with a 60-minute head-down tilt induces the release of ANP and cGMP during both hypoxia and normoxia. Hypoxia increased cGMP, cAMP, ALD, and PRA throughout the protocol and significantly potentiated the increase in cGMP during head-down tilt. Hypoxia had no overall effect on the release of ANP, but appeared to attenuate the increase with head-down tilt. This study describes the acute effects of hypoxia on the endocrine response during fluid redistribution and suggests that the magnitude, but not the direction, of these changes with posture is affected by hypoxia.

Effect of standardized orders and provider education on head-of-bed positioning in mechanically ventilated patients.

Science.gov (United States)

Helman, Donald L; Sherner, John H; Fitzpatrick, Thomas M; Callender, Marcia E; Shorr, Andrew F

2003-09-01

Semirecumbent head-of-bed positioning in mechanically ventilated patients decreases the risk of developing ventilator-associated pneumonia (VAP). The purpose of this study was to determine whether the addition of a standardized order followed by the initiation of a provider education program would increase the frequency with which our patients were maintained in the semirecumbent position. Prospective, pre-, and postintervention observational study. A tertiary care, U.S. Army teaching hospital. Mechanically ventilated medical and surgical intensive care unit patients. The first intervention involved the addition of an order for semirecumbent head-of-bed positioning to our intensive care unit order sets. This was followed 2 months later with a second intervention, which was a nurse and physician education program emphasizing semirecumbent positioning. Data regarding head-of-bed positioning were collected on 100 patient observations at baseline and at 1 and 2 months after each of our interventions. The mean angle of head of bed increased from 24 +/- 9 degrees at baseline to 35 +/- 9 degrees (p 45 degrees increased from 3% to 16% 2 months after the standardized order (p patients with head of bed >45 degrees was 29% (p = NS compared with values after the first intervention). Data collected 6 months after completion of our education programs showed that these improvements were maintained. Standardizing the process of care via the addition of an order specifying head-of-bed position significantly increased the number of patients who were placed in the semirecumbent position. In an era of cost-conscious medicine, interventions that utilize protocols and education programs should be emphasized.

Particle Distribution in a Fixed Bed Down Draft Wood Gasifier

DEFF Research Database (Denmark)

Hindsgaul, Claus

2005-01-01

Char particle samples were collected from six distances above the grate in a fixed bed of a down draft biomass gasifier. Each sample was separated into twelve size fractions by screening through standard sieves in order to determine the local particle size distribution. The ash contents of each...

The application of quality control circle in neurosurgery ICU nurses in raising compliance of the head of a bed

Directory of Open Access Journals (Sweden)

Na LI

2014-11-01

Full Text Available Objective: To explore the application of quality control circle in raising compliance of the head of a bed in neurosurgery ICU nurses. Methods: The quality control circle was made up of 4 ICU nurses, determine the subject in order to improve the neurosurgery ICU nurses in raising compliance of the head of a bed, according to the QCC activity steps to formulate plans, including grasp the current situation, goal setting, through analysis, circle members develop strategy and plan implementation and review, finally compared the situation before and after neurosurgery ICU nurses raised bed activities compliance. Results: After implementation of QCC, neurosurgery ICU nurses raised bed to 30 ~ 45 degrees. After activities, circle members in the team cooperation ability, cohesion, to accept new things ability, and innovative thinking ability and to raise the understanding of the relevant knowledge of the head of a bed has improved significantly. Conclusion: The application of quality management circle activity improves the neurosurgery ICU nurses effectively raise the compliance of the head of a bed, improve the comprehensive quality of the clinical nurses.

Gastrointestinal Physiology During Head Down Tilt Bedrest in Human Subjects

Science.gov (United States)

Vaksman, Z.; Guthienz, J.; Putcha, L.

2008-01-01

Introduction: Gastrointestinal (GI) motility plays a key role in the physiology and function of the GI tract. It directly affects absorption of medications and nutrients taken by mouth, in addition to indirectly altering GI physiology by way of changes in the microfloral composition and biochemistry of the GI tract. Astronauts have reported nausea, loss of appetite and constipation during space flight all of which indicate a reduction in GI motility and function similar to the one seen in chronic bed rest patients. The purpose of this study is to determine GI motility and bacterial proliferation during -6 degree head down tilt bed rest (HTD). Methods: Healthy male and female subjects between the ages of 25-40 participated in a 60 day HTD study protocol. GI transit time (GITT) was determined using lactulose breath hydrogen test and bacterial overgrowth was measured using glucose breath hydrogen test. H. Pylori colonization was determined using C13-urea breath test (UBIT#). All three tests were conducted on 9 days before HDT, and repeated on HDT days 2, 28, 58, and again on day 7 after HDT. Results: GITT increased during HTD compared to the respective ambulatory control values; GITT was significantly lower on day 7 after HTD. A concomitant increase in bacterial colonization was also noticed during HDT starting after approximately 28 days of HDT. However, H. Pylori proliferation was not recorded during HDT as indicated by UBIT#. Conclusion: GITT significantly decreased during HDT with a concomitant increase in the proliferation of GI bacterial flora but not H. pylori.

An evidence-based recommendation on bed head elevation for mechanically ventilated patients.

Science.gov (United States)

Niël-Weise, Barbara S; Gastmeier, Petra; Kola, Axel; Vonberg, Ralf P; Wille, Jan C; van den Broek, Peterhans J

2011-01-01

A semi-upright position in ventilated patients is recommended to prevent ventilator-associated pneumonia (VAP) and is one of the components in the Ventilator Bundle of the Institute for Health Care Improvement. This recommendation, however, is not an evidence-based one. A systematic review on the benefits and disadvantages of semi-upright position in ventilated patients was done according to PRISMA guidelines. Then a European expert panel developed a recommendation based on the results of the systematic review and considerations beyond the scientific evidence in a three-round electronic Delphi procedure. Three trials (337 patients) were included in the review. The results showed that it was uncertain whether a 45° bed head elevation was effective or harmful with regard to the occurrence of clinically suspected VAP, microbiologically confirmed VAP, decubitus and mortality, and that it was unknown whether 45° elevation for 24 hours a day increased the risk for thromboembolism or hemodynamic instability. A group of 22 experts recommended elevating the head of the bed of mechanically ventilated patients to a 20 to 45° position and preferably to a ≥ 30° position as long as it does not pose risks or conflicts with other nursing tasks, medical interventions or patients' wishes. Although the review failed to prove clinical benefits of bed head elevation, experts prefer this position in ventilated patients. They made clear that the position of a ventilated patient in bed depended on many determinants. Therefore, given the scientific uncertainty about the benefits and harms of a semi-upright position, this position could only be recommended as the preferred position with the necessary restrictions.

Advances and trends of head-up and head-down display systems in automobiles

Science.gov (United States)

Betancur, J. Alejandro; Osorio-Gomez, Gilberto; Agudelo, J. David

2014-06-01

Currently, in the automotive industry the interaction between drivers and Augmented Reality (AR) systems is a subject of analysis, especially the identification of advantages and risks that this kind of interaction represents. Consequently, this paper attempts to put in evidence the potential applications of Head-Up (Display (HUD) and Head-Down Display (HDD) systems in automotive vehicles, showing applications and trends under study. In general, automotive advances related to AR devices suggest the partial integration of the HUD and HDD in automobiles; however, the right way to do it is still a moot point.

Time of elevation of head of bed for patients receiving mechanical ventilation and its related factors.

Science.gov (United States)

Martí-Hereu, L; Arreciado Marañón, A

The semirecumbent position is a widespread recommendation for the prevention of pneumonia associated with mechanical ventilation. To identify the time of elevation of head of bed for patients under mechanical ventilation and the factors related to such elevation in an intensive care unit. An observational, descriptive cross-sectional study. Conducted in an intensive care unit of a tertiary hospital from April to June 2015. The studied population were mechanically ventilated patients. Daily hours in which patients remained with the head of the bed elevated (≥30°), socio-demographic data and clinical variables were recorded. 261 head elevation measurements were collected. The average daily hours that patients remained at ≥30° was 16h28' (SD ±5h38'), equivalent to 68.6% (SD ±23.5%) of the day. Factors related to elevations ≥30° for longer were: enteral nutrition, levels of deep sedation, cardiac and neurocritical diagnostics. Factors that hindered the position were: sedation levels for agitation and abdominal pathologies. Sex, age and ventilation mode did not show a significant relationship with bed head elevation. Although raising the head of the bed is an easy to perform, economical and measurable preventive measure, its compliance is low due to specific factors specific related o the patient's clinical condition. Using innovations such as continuous measurement of the head position helps to evaluate clinical practice and allows to carry out improvement actions whose impact is beneficial to the patient. Copyright © 2017 Sociedad Española de Enfermería Intensiva y Unidades Coronarias (SEEIUC). Publicado por Elsevier España, S.L.U. All rights reserved.

Hydroelectrolytic and hormonal modifications related to prolonged bedrest in antiorthostatic position

Science.gov (United States)

Güell, A.; Dupui, Ph.; Fanjaud, G.; Bes, A.; Moatti, J. P.; Gharrib, Cl.

The effects of prolonged bedrest in antiorthostatic position (-4° head down) on electrolyte balance were studied in 4 young volunteers. An increase was noted in sodium excretion during the first 4 days. Plasma renin activity and plasma aldosterone varied in parallel manner during the same period. Potassium balance and creatinine clearance were not significantly modified. In light of these data we feel that prolonged bedrest in antiorthostatic position constitutes an effective way to simulate on earth metabolic and hormonal modifications occurring in man under weightlessness conditions.

Effects of long-duration bed rest on structural compartments of m. soleus in man

Science.gov (United States)

Belozerova, I.; Shenkman, B.; Mazin, M.; Leblanc, A.; LeBlanc, A. D. (Principal Investigator)

2001-01-01

Magnetic resonance imaging (MRI), histomorphometry and electron microscopy of muscle demonstrate that long-term exposure to actual or simulated weightlessness (including head down bed rest) leads to decreased volume of antigravity muscles in mammals. In muscles interbundle space is occupied by the connective tissue. Rat studies show that hindlimb unloading induces muscle fiber atrophy along with increase in muscle non-fiber connective tissue compartment. Beside that, usually 20% of the muscle fiber volume is comprised by non-contractile (non-myofibrillar) compartment. The aim of the present study was to compare changes in muscle volume, and in muscle fiber size with alterations in myofibrillar apparatus, and in connective tissue compartment in human m. soleus under conditions of 120 day long head down bed rest (HDBR).

Down-flow moving-bed gasifier with catalyst recycle

Science.gov (United States)

Halow, John S.

1999-01-01

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction.

The Effects of Long Duration Bed Rest as a Spaceflight Analogue on Resting State Sensorimotor Network Functional Connectivity and Neurocognitive Performance

Science.gov (United States)

Cassady, K.; Koppelmans, V.; Yuan, P.; Cooke, K.; De Dios, Y.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S.; Reuter-Lorenz, P.;

Case Report: Down-staging locally advanced head and neck cancer ...

African Journals Online (AJOL)

big meta-analysis of chemotherapy in head and neck cancer. (MACH-NC) involving over ... and neck cancer of squamous cell histology, HIV infected who was down-staged ... of the submitted specimen confirmed ulcerated oral mucosa with an ...

Supraesophageal Reflux: Correlation of Position and Occurrence of Acid Reflux-Effect of Head-of-Bed Elevation on Supine Reflux.

Science.gov (United States)

Scott, David R; Simon, Ronald A

2015-01-01

Supraesophageal reflux of gastric contents can contribute to perennial nasopharyngitis, cough, and asthma. However, effective treatment strategies for supraesophageal reflux disease (SERD) remain inadequately defined. The purpose of this study is to assess the prevalence and timing of SERD and to investigate the efficacy of head-of-bed elevation in its treatment. A retrospective chart review of patients seen at Scripps Clinic Division of Allergy, Asthma and Immunology was performed who had undergone overnight nasopharyngeal pH monitoring with a commercially available nasopharyngeal pH-monitoring device, Dx-pH Measurement System from Restech, San Diego, Calif. Subjects with reflux were classified based on the position of reflux as either supine only, upright only, or both supine and upright. In a subset of subjects with supine-only reflux, pH monitoring was compared before and after elevating the head of bed 6 inches. Adequate nasopharyngeal pH-monitoring data were obtained for 235 patients. Reflux was detected in 113 (48%) patients. The pattern of reflux observed was 62 (55%) supine only, 4 (4%) upright only, and 47 (42%) upright and supine. Sequential overnight nasopharyngeal pH monitoring before and after head-of-bed elevation was obtained in 13 individuals with supine-only reflux. Ten subjects demonstrated significant improvement, 8 of whom demonstrated complete resolution of supine reflux with 6 inches of head-of-bed elevation. This study provides new evidence that SERD frequently occurs in the supine position and that 6 inches of head-of-bed elevation is effective in reducing supine SERD. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Effect of Head-Down Bed Rest and Artificial Gravity Countermeasure on Cardiac Autonomic and Advanced Electrocardiographic Function

Science.gov (United States)

Schlegel, T. T.; Platts, S.; Stenger, M.; Ribeiro, C.; Natapoff, A.; Howarth, M.; Evans, J.

2007-01-01

To study the effects of 21 days of head-down bed rest (HDBR), with versus without an artificial gravity (AG) countermeasure, on cardiac autonomic and advanced electrocardiographic function. Fourteen healthy men participated in the study: seven experienced 21 days of HDBR alone ("HDBR controls") and seven the same degree and duration of HDBR but with approximately 1hr daily short-arm centrifugation as an AG countermeasure ("AG-treated"). Five minute supine high-fidelity 12-lead ECGs were obtained in all subjects: 1) 4 days before HDBR; 2) on the last day of HDBR; and 3) 7 days after HDBR. Besides conventional 12-lead ECG intervals and voltages, all of the following advanced ECG parameters were studied: 1) both stochastic (time and frequency domain) and deterministic heart rate variability (HRV); 2) beat-to-beat QT interval variability (QTV); 3) T-wave morphology, including signal-averaged T-wave residua (TWR) and principal component analysis ratios; 4) other SAECG-related parameters including high frequency QRS ECG and late potentials; and 5) several advanced ECG estimates of left ventricular (LV) mass. The most important results by repeated measures ANOVA were that: 1) Heart rates, Bazett-corrected QTc intervals, TWR, LF/HF power and the alpha 1 of HRV were significantly increased in both groups (i.e., by HDBR), but with no relevant HDBR*group differences; 2) All purely "vagally-mediated" parameters of HRV (e.g., RMSSD, HF power, Poincare SD1, etc.), PR intervals, and also several parameters of LV mass (Cornell and Sokolow-Lyon voltages, spatial ventricular activation times, ventricular gradients) were all significantly decreased in both groups (i.e., by HDBR), but again with no relevant HDBR*group differences); 3) All "generalized" or "vagal plus sympathetic" parameters of stochastic HRV (i.e., SDNN, total power, LF power) were significantly more decreased in the AG-treated group than in the HDBR-only group (i.e., here there was a relevant HDBR*group difference

Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control

Science.gov (United States)

Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.

2011-01-01

Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed

Changes in markers of bone formation and resorption in a bed rest model of weightlessness

Science.gov (United States)

Lueken, S. A.; Arnaud, S. B.; Taylor, A. K.; Baylink, D. J.

1993-01-01

To study the mechanism of bone loss in physical unloading, we examined indices of bone formation and bone resorption in the serum and urine of eight healthy men during a 7 day -6 degrees head-down tilt bed rest. Prompt increases in markers of resorption--pyridinoline (PD), deoxypyridinoline (DPD), and hydroxyproline (Hyp)/g creatinine--during the first few days of inactivity were paralleled by tartrate-resistant acid phosphatase (TRAP) with significant increases in all these markers by day 4 of bed rest. An index of formation, skeletal alkaline phosphatase (SALP), did not change during bed rest and showed a moderate 15% increase 1 week after reambulation. In contrast to SALP, serum osteocalcin (OC) began increasing the day preceding the increase in Hyp, remained elevated for the duration of the bed rest, and returned to pre-bed rest values within 5 days of reambulation. Similarly, DPD increased significantly at the onset of bed rest, remained elevated for the duration of bed rest, and returned to pre-bed rest levels upon reambulation. On the other hand, the other three indices of resorption, Hyp, PD, and TRAP, remained elevated for 2 weeks after reambulation. The most sensitive indices of the levels of physical activity proved to be the noncollagenous protein, OC, and the collagen crosslinker, DPD. The bed rest values of both these markers were significantly elevated compared to both the pre-bed rest values and the post-bed rest values. The sequence of changes in the circulating markers of bone metabolism indicated that increases in serum OC are the earliest responses of bone to head-down tilt bed rest.

Case Report: Down-staging locally advanced head and neck cancer ...

African Journals Online (AJOL)

Case Report: Down-staging locally advanced head and neck cancer in an HIV infected patient in a limited resource setting. L Masamba, D Nkosi, D Kumiponjera. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals ...

THE EFFECTS OF PROLONGED PHYSICAL INACTIVITY INDUCED BY BED REST ON COGNITIVE FUNCTIONING IN HEALTHY MALE PARTICIPANTS

Directory of Open Access Journals (Sweden)

Petra Dolenc

2013-06-01

Full Text Available A growing body of scientific evidence indicates that physical activity beneficially influences cognitive functioning. Less thoroughly investigated are the cognitive outcomes of reduced physical activity levels. The purpose of the study was to determine the effects of prolonged physical inactivity induced by bed rest on the participant’s cognitive functioning. Bed rest is a well-accepted method by which an acute stage of human adaptation to weightlessness in space flights is simulated, as well as an important model to study the consequences of extreme physical inactivity in humans. The subjects participating in the study consisted of fifteen healthy males aged between 19 and 65 years who were exposed to 14-day horizontal bed rest in a strict hospital environment. To assess the cognitive functions of the participants, a neuropsychological test battery was administered before and after the bed rest experiment. There was no significant impairment in cognitive performance after the 14-day bed rest on all tests, except in the measurements of delayed recall in the group of older adults. The results suggest that cognitive functions remained relatively stable during the period of physical immobilization. The obtained results have been discussed taking the possible contributing factors into account such as the practice effect, the relatively short duration of bed rest, and the choice of the cognitive measures administered. The study also provides evidence that favourable living and psychosocial conditions can protect one against cognitive decline in the case of extreme physical inactivity.

Death in head-down position in a heavily intoxicated obese man.

Science.gov (United States)

De Donno, A; De Fazio, A; Greco, M G; Introna, F; Maglietta, R A G

2008-07-01

Dying in a head-down position is rare, and autopsy may reveal no morphological findings which can sufficiently explain the cause of death. The authors describe a case of positional asphyxia of a 78-year-old man, found dead hanging in head-down position inside a blackberry bush. The subject was suspended by his left leg and wedged inside a thick blackberry bush, while his right leg was free and inflected. Investigation revealed that the elderly man had last been seen after lunch in the early afternoon (about 2.00 p.m.), two days before being found. The subject had no pre-existing physical or mental condition which might have explained his death. He was 164 cm tall and weighed 90 kg (BMI: 33.4). External examination of the body revealed abrasions on the head and multiple superficial scratch marks on the hands; no external signs of violence were observed. The deceased's head was cyanotic and revealed marked petechial haemorrhages of the conjunctiva. Rigor mortis was fully developed and reddish fixed livor was observed on the face, neck and upper chest. The distribution of livor was consistent with the position of the body at the scene. Autopsy revealed marked pulmonary and cerebral oedema; the liver showed fatty vacuolization with a mild increase of connective tissue and thickening of the walls of the central veins and centrilobular sinusoids. The heart was enlarged, particularly the left ventricle, with a slight, calcified, diffuse and increased thickness of the aortic and coronary arteries. The remains of meat and vegetables in the initial phase of digestion were found inside the stomach, and there was a strong smell of alcohol. The blood alcohol concentration, ascertained by GC (Gas Chromatography), was 2.10 g/l. Toxicological assays for addictive drugs (cocaine, heroin, THC) yielded negative results. There were no features suggesting that the deceased had been the victim of an assault. The authors of this case report illustrate the main pathophysiological and

Prolonged Tp-e Interval in Down Syndrome Patients with Congenitally Normal Hearts.

Science.gov (United States)

Kucuk, Mehmet; Karadeniz, Cem; Ozdemir, Rahmi; Meşe, Timur

2018-03-25

Heterogeneity of ventricular repolarization has been assessed by using the QT dispersion in Down syndrome (DS) patients with congenitally normal hearts. However, novel repolarization indexes, the Tp-e interval and Tp-e/QT ratio, have not previously been evaluated in these patients. The aim of this study was to evaluate the Tp-e interval and Tp-e/QT ratio in DS patients without congenital heart defects. Twelve-lead surface electrocardiograms of 160 DS patients and 110 age- and sex-matched healthy controls were used to evaluate and compare the Tp-e interval, Tp-e dispersion, and Tp-e/QT ratio. Heart rate, Tp-e interval, Tp-e dispersion, Tp-e/QT and Tp-e/QTc ratios were significantly higher in DS group than in the controls. Myocardial repolarization indexes in DS patients with congenitally normal hearts were found to be prolonged compared to those in normal controls. Further evaluation is warranted to reveal a relationship between prolonged repolarization indexes and arrhythmic events in these patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The influence of gravity on regional lung blood flow in humans: SPECT in the upright and head-down posture.

Science.gov (United States)

Ax, M; Sanchez-Crespo, A; Lindahl, S G E; Mure, M; Petersson, J

2017-06-01

Previous studies in humans have shown that gravity has little influence on the distribution of lung blood flow while changing posture from supine to prone. This study aimed to evaluate the maximal influence of posture by comparison of regional lung blood flow in the upright and head-down posture in 8 healthy volunteers, using a tilt table. Regional lung blood flow was marked by intravenous injection of macroaggregates of human albumin labeled with 99m Tc or 113m In, in the upright and head-down posture, respectively, during tidal breathing. Both radiotracers remain fixed in the lung after administration. The distribution of radioactivity was mapped using quantitative single photon emission computed tomography (SPECT) corrected for attenuation and scatter. All images were obtained supine during tidal breathing. A shift from upright to the head-down posture caused a clear redistribution of blood flow from basal to apical regions. We conclude that posture plays a role for the distribution of lung blood flow in upright humans, and that the influence of posture, and thereby gravity, is much greater in the upright and head-down posture than in horizontal postures. However, the results of the study demonstrate that lung structure is the main determinant of regional blood flow and gravity is a secondary contributor to the distribution of lung blood flow in the upright and head-down positions. NEW & NOTEWORTHY Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes blood flow in the direction of gravity, the results are also consistent with lung structure being a greater determinant of regional blood flow than gravity. To our knowledge, this is the first study to use modern imaging methods to quantify the shift in regional lung blood flow in humans at a change between the upright and head-down postures. Copyright © 2017 the American Physiological Society.

The Safety of Hospital Beds: Ingress, Egress, and In-Bed Mobility.

Science.gov (United States)

Morse, Janice M; Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients' ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients' use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated.

Effects of head down tilt on episcleral venous pressure in a rabbit model.

Science.gov (United States)

Lavery, W J; Kiel, J W

2013-06-01

In humans, changing from upright to supine elicits an approximately 10 mmHg increase in cephalic venous pressure caused by the hydrostatic column effect, but episcleral venous pressure (EVP) and intraocular pressure (IOP) rise by only a few mmHg. The dissociation of the small increases in IOP and EVP compared to the larger increase in cephalic venous pressure suggests a regulatory mechanism controlling EVP. The aim of the present study was to determine if the rabbit model is suitable to study the effects of postural changes on EVP despite its short hydrostatic column. In anesthetized rabbits (n = 43), we measured arterial pressure (AP), IOP, and orbital venous pressure (OVP) by direct cannulation; carotid blood flow (BFcar) by transit time ultrasound, heart rate (HR) by digital cardiotachometer, and EVP with a servonull micropressure system. The goal of the protocol was to obtain measurement of supine EVP for ≈10 min, followed by ≈10 min of EVP measurement with the rabbit in a head down tilt. The data were analyzed by paired t-tests and the results reported as the mean ± standard error of the mean. In a separate group of animals (n = 35), aqueous flow was measured by fluorophotometry. This protocol entailed measurement of aqueous flow in the supine position for ≈60 min, followed by ≈60 min of aqueous flow measurement with the rabbit in a head down tilt. From supine to head down tilt, AP and BFcar were unchanged, IOP increased by 2.3 ± 0.4 mmHg (p measurements of the pressures and systemic parameters likely involved in the EVP responses to posture change. The present results indicate directionally similar EVP and IOP responses to tilt as occur in humans and, as in humans, the responses are smaller than would be expected from the change in the hydrostatic column height. Also, as in humans, the model reveals no change in aqueous flow during head down tilt. We conclude the rabbit model is appropriate for studying the mechanisms responsible for the relative

Bed Rest is an Analog to Study the Physiological Changes of Spaceflight and to Evaluate Countermeasures

Science.gov (United States)

Pfannenstiel, P.; Ottenbacher, M.; Inniss, A.; Ware, D.; Anderson, K.; Stranges, S.; Keith, K.; Cromwell, R.; Neigut. J.; Powell, D.

2012-01-01

The UTMB/NASA Flight Analog Research Unit is an inpatient unit with a bionutrition kitchen and unique testing areas for studying subjects subjected to 6 degree head-down complete bed rest for prolonged periods as an analog for zero gravity. Bed rest allows study of physiological changes and performance of functional tasks representative of critical interplanetary mission operations and measures of the efficacy of countermeasures designed to protect against the resulting deleterious effects. METHODS/STUDY POPULATION: Subjects are healthy adults 24-55 years old; 60 75 in tall; body mass index 18.5-30; and bone mineral density normal by DXA scan. Over 100 subjects have been studied in 7 campaigns since 2004. The iRAT countermeasure combines high intensity interval aerobic exercises on alternating days with continuous aerobic exercise. Resistance exercise is performed 3 days per week. Subjects are tested on an integrated suite of functional and interdisciplinary physiological tests before and after 70 days of total bed rest. RESULTS/ANTICIPATED RESULTS: It is anticipated that post-bed rest functional performance will be predicted by a weighted combination of sensorimotor, cardiovascular and muscle physiological factors. Control subjects who do not participate in the exercise countermeasure will have significantly greater decreases in these parameters. DISCUSSION/SIGNIFICANCE OF IMPACT: Astronauts experience alterations in multiple physiological systems due to exposure to the microgravity, leading to disruption in the ability to perform functional tasks after reintroduction to a gravitational environment. Current flight exercise countermeasures are not fully protective of cardiovascular, muscle and bone health. There is a need to refine and optimize countermeasures to mitigate health risks associated with long-term space missions.

Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: Effects of -6 degree head-down tilt bed rest

Directory of Open Access Journals (Sweden)

Li-Lin eRao

2014-05-01

Full Text Available Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals’ risk-taking behavior and the neural basis of the effect. The results showed that participants’ risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning.

Comparison of acute cardiovascular responses to water immersion and head-down tilt in humans

DEFF Research Database (Denmark)

Shiraishi, Makoto; Schou, Morten; Gybel, Mikkel

2002-01-01

The hypothesis was tested that acute water immersion to the neck (WI) compared with 6 degrees head-down tilt (HDT) induces a more pronounced distension of the heart and lower plasma levels of vasoconstrictor hormones. Ten healthy males underwent 30 min of HDT, WI, and a seated control (randomized...

Pebble-bed reactor

International Nuclear Information System (INIS)

Lohnert, G.; Mueller-Frank, U.; Heil, J.

1976-01-01

A pebble-bed nuclear reactor of large power rating comprises a container having a funnel-shaped bottom forming a pebble run-out having a centrally positioned outlet. A bed of downwardly-flowing substantially spherical nuclear fuel pebbles is positioned in the container and forms a reactive nuclear core maintained by feeding unused pebbles to the bed's top surface while used or burned-out pebbles run out and discharge through the outlet. A substantially conical body with its apex pointing upwardly and its periphery spaced from the periphery of the container spreads the bottom of the bed outwardly to provide an annular flow down the funnel-shaped bottom forming the runout, to the discharge outlet. This provides a largely constant downward velocity of the spheres throughout the diameter of the bed throughout a substantial portion of the down travel, so that all spheres reach about the same burned-out condition when they leave the core, after a single pass through the core area

The Safety of Hospital Beds

Science.gov (United States)

Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K.; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients’ ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients’ use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated. PMID:28462302

Decreasing ventromedial prefrontal cortex deactivation in risky decision making after simulated microgravity: effects of −6° head-down tilt bed rest

Science.gov (United States)

Rao, Li-Lin; Zhou, Yuan; Liang, Zhu-Yuan; Rao, Henyi; Zheng, Rui; Sun, Yan; Tan, Cheng; Xiao, Yi; Tian, Zhi-Qiang; Chen, Xiao-Ping; Wang, Chun-Hui; Bai, Yan-Qiang; Chen, Shan-Guang; Li, Shu

2014-01-01

Space is characterized by risk and uncertainty. As humans play an important role in long-duration space missions, the ability to make risky decisions effectively is important for astronauts who spend extended time periods in space. The present study used the Balloon Analog Risk Task to conduct both behavioral and fMRI experiments to evaluate the effects of simulated microgravity on individuals' risk-taking behavior and the neural basis of the effect. The results showed that participants' risk-taking behavior was not affected by bed rest. However, we found that the ventromedial prefrontal cortex (VMPFC) showed less deactivation after bed rest and that the VMPFC activation in the active choice condition showed no significant difference between the win outcome and the loss outcome after bed rest, although its activation was significantly greater in the win outcome than in the loss outcome before bed rest. These results suggested that the participants showed a decreased level of value calculation after the bed rest. Our findings can contribute to a better understanding of the effect of microgravity on individual higher-level cognitive functioning. PMID:24904338

Intensity-Modulated Radiotherapy With Use of Cone-Down Boost for Pediatric Head-and-Neck Rhabdomyosarcoma

International Nuclear Information System (INIS)

McDonald, Mark W.; Esiashvili, Natia; George, Bradley A.; Katzenstein, Howard M.; Olson, Thomas A.; Rapkin, Louis B.; Marcus, Robert B.

2008-01-01

Purpose: To report our initial experience using intensity-modulated radiotherapy (IMRT) with a cone-down boost for pediatric head-and-neck rhabdomyosarcoma (RMS). Methods and Materials: A review of institutional treatment records identified children treated with IMRT for head-and-neck RMS between January 2000 and February 2007. All patients had undergone chemotherapy according to cooperative group RMS protocols. The initial planning target volume (PTV) covered the prechemotherapy tumor extent with variable margins, generally 1-2 cm. The boost PTV covered the postchemotherapy tumor volume, usually with a margin of 0.5-1 cm. Results: A total of 20 patients were treated with IMRT for head-and-neck RMS. Of these 20 patients, 4 had Group II, 15 Group III, and 1 Group IV disease. The site was parameningeal in 12, nonparameningeal in 6, and orbit primary in 2. Of the 20 patients, 14 were treated with a cone-down boost after a median dose of 36 Gy (range, 30-45.6). The mean initial PTV was 213.5 cm 3 , and the mean boost PTV was 76.9 cm 3 . Patients received a median total dose of 50.4 Gy. The median follow-up time was 29 months. The 3-year Kaplan-Meier local control rate was 100%, although 1 patient developed an in-field recurrence 50 months after IMRT. The 3-year event-free survival rate, overall survival rate, and risk of central nervous system failure was 74%, 76%, and 7%, respectively. Conclusions: Our preliminary follow-up of pediatric head-and-neck RMS patients treated with IMRT revealed excellent local control. The initial targeting of the prechemotherapy tumor volume with 1-2-cm margin to 30.6 or 36 Gy followed by a cone-down boost to the postchemotherapy tumor volume with a 0.5-1-cm margin allowed for significant sparing of normal tissues and provided good local control

Bed rest attenuates sympathetic and pressor responses to isometric exercise in antigravity leg muscles in humans.

Science.gov (United States)

Kamiya, Atsunori; Michikami, Daisaku; Shiozawa, Tomoki; Iwase, Satoshi; Hayano, Junichiro; Kawada, Toru; Sunagawa, Kenji; Mano, Tadaaki

2004-05-01

Although spaceflight and bed rest are known to cause muscular atrophy in the antigravity muscles of the legs, the changes in sympathetic and cardiovascular responses to exercises using the atrophied muscles remain unknown. We hypothesized that bed rest would augment sympathetic responses to isometric exercise using antigravity leg muscles in humans. Ten healthy male volunteers were subjected to 14-day 6 degrees head-down bed rest. Before and after bed rest, they performed isometric exercises using leg (plantar flexion) and forearm (handgrip) muscles, followed by 2-min postexercise muscle ischemia (PEMI) that continues to stimulate the muscle metaboreflex. These exercises were sustained to fatigue. We measured muscle sympathetic nerve activity (MSNA) in the contralateral resting leg by microneurography. In both pre- and post-bed-rest exercise tests, exercise intensities were set at 30 and 70% of the maximum voluntary force measured before bed rest. Bed rest attenuated the increase in MSNA in response to fatiguing plantar flexion by approximately 70% at both exercise intensities (both P antigravity leg muscles.

Effects of head down tilt upon cortisol and sex hormones

Science.gov (United States)

Strollo, Felice; Pecorelli, Lia; Uva, Bianca Maria; Masini, Maria Angela; More, Massimo; Strollo, Giovanna; Riondino, Giuseppe

2005-08-01

Real and modelled μG conditions seem to induce reversible testicular failure. Suitable onground simulation methods are anyway needed in order to better aim further studies in humans in space. A 5- hour head down tilt (5h-HDT) was therefore performed in 22 male and female healthy volunteers looking at adrenal and gonadal hormones as compared to 12 age- and gender- matched controls. Cortisol and A decreased significantly in both genders, being cortisol decrease less pronounced in women, while leptin, LH, testosterone, estradiol and estrone failed to do so. The authors conclude that a 5h-HDT is only acceptable for adrenal adaptation studies whole longer duration HDT protocols are needed for gonadal investigations.

Prolonged postoperative desaturation in a child with Down syndrome and atrial septal defect

Directory of Open Access Journals (Sweden)

Renu Sinha

2011-01-01

Full Text Available We report prolonged desaturation in a child with Down syndrome (DS and atrial septal defect due to undiagnosed interstitial lung disease. An 18-month-old child with DS was scheduled for bilateral lens aspiration for cataract. The child had atrial septal defect and hypothyroidism. He also had delayed milestones and hypotonia with episodes of recurrent respiratory tract infection necessitating repeated hospitalization. Preoperative evaluation was unremarkable. General anaesthesia and controlled ventilation using proseal laryngeal mask airway was instituted. He had uneventful intraoperative period. In the postoperative period, the child had desaturation 1 hour after surgery on discontinuation of oxygen supplementation by face mask, which improved with oxygen therapy. Supplemental oxygen via face mask was continued and weaned off over several days. On further evaluation, the child was diagnosed as having interstitial lung disease. He improved and discharged from the hospital 15 days after the surgery with room air saturation of 90%.

Experimental study of head loss and filtration for LOCA debris

International Nuclear Information System (INIS)

Rao, D.V.; Souto, F.J.

1996-02-01

A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON trademark fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors

The NASA Bed Rest Project

Science.gov (United States)

Rhodes, Bradley; Meck, Janice

2005-01-01

NASA s National Vision for Space Exploration includes human travel beyond low earth orbit and the ultimate safe return of the crews. Crucial to fulfilling the vision is the successful and timely development of countermeasures for the adverse physiological effects on human systems caused by long term exposure to the microgravity environment. Limited access to in-flight resources for the foreseeable future increases NASA s reliance on ground-based analogs to simulate these effects of microgravity. The primary analog for human based research will be head-down bed rest. By this approach NASA will be able to evaluate countermeasures in large sample sizes, perform preliminary evaluations of proposed in-flight protocols and assess the utility of individual or combined strategies before flight resources are requested. In response to this critical need, NASA has created the Bed Rest Project at the Johnson Space Center. The Project establishes the infrastructure and processes to provide a long term capability for standardized domestic bed rest studies and countermeasure development. The Bed Rest Project design takes a comprehensive, interdisciplinary, integrated approach that reduces the resource overhead of one investigator for one campaign. In addition to integrating studies operationally relevant for exploration, the Project addresses other new Vision objectives, namely: 1) interagency cooperation with the NIH allows for Clinical Research Center (CRC) facility sharing to the benefit of both agencies, 2) collaboration with our International Partners expands countermeasure development opportunities for foreign and domestic investigators as well as promotes consistency in approach and results, 3) to the greatest degree possible, the Project also advances research by clinicians and academia alike to encourage return to earth benefits. This paper will describe the Project s top level goals, organization and relationship to other Exploration Vision Projects, implementation

Characterization of the vascular bed of head-and neck advanced tumors by radioactive emboli

International Nuclear Information System (INIS)

Serson, D.

1982-01-01

A radioisotopic method, using labeled particles for the determination of regions irrigated by an artery is established. Patients with advanced head and neck cancer were studied, whose treatment was carried out with antiblastics by intra-arterial via. To check the vascular territory early reached by intra-arterial chemotherapy we used albumin macro-particles labeled with iodine 131. The method resulted harmless and of great importance for localization of the tumor bed. It was also observed that the method may be used for localization of the chemotherapic infusion in other sectors of the body or for the anatomic determination of the arterial vascularization. (Author) [pt

The relationship between carbon stable isotope ratios of hatchling down and egg yolk in Black-headed Gulls

NARCIS (Netherlands)

Klaassen, M.R.J.; Baarspul, T.; Dekkers, T.; Van Tienen, P.

2004-01-01

We reconstructed the nutrient source for egg synthesis by sampling Black-headed Gull (Larus ridibundus) eggs for yolk, analyzing their carbon stable isotope ratio, and comparing that to hatchling down. Most of the variation in carbon stable isotope ratio was explained by differences between nests,

Head Lice

Science.gov (United States)

... nits. You should also use hot water to wash any bed linens, towels, and clothing recently worn by the person who had head lice. Vacuum anything that can’t be washed, such as the couch, carpets, your child’s car seat, and any stuffed animals. Because head lice ...

Numerical models for the analysis of thermal behavior and coolability of a particulate debris bed in reactor lower head

Energy Technology Data Exchange (ETDEWEB)

Ahn, Kwang Il; Kim, Sang Baik; Kim, Byung Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-04-01

This report provides three distinctive, but closely related numerical models developed for the analysis of thermal behavior and coolability of a particulate debris bed that is may be formed inside the reactor lower head during severe accident late phases. The first numerical module presented in the report, MELTPRO-DRY, is used to analyze numerically heat-up and melting process of the dry particle bed, downward- and sideward-relocation of the liquid melt under gravity force and capillary force acting among porous particles, and solidification of the liquid melt relocated into colder region. The second module, MELTPROG-WET, is used to simulate numerically the cooling process of the particulate debris bed under the existence of water, which is subjected to two types of numerical models. The first type of WET module utilizes distinctive models that parametrically simulate the water cooling process, that is, quenching region, dryout region, and transition region. The choice of each parametric model depends on temperature gradient between the cooling water and the debris particles. The second type of WET module utilizes two-phase flow model that mechanically simulates the cooling process of the debris bed. For a consistent simulation from the water cooling to the dryout debris bed, on the other hand, the aforementioned two modules, MELTPROG-DRY and MELTPROG-WET, were integrated into a single computer program DBCOOL. Each of computational models was verified through limited applications to a heat-generating particulate bed contained in the rectangular cavity. 22 refs., 5 figs., 2 tabs. (Author)

Hospital bed ventilation: impact of operation mode on exposure

DEFF Research Database (Denmark)

Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Barova, Mariya

2014-01-01

a second patient lying in the other bed. The doctor stood up 0.55 m from the bed facing the sick patient. Two pairs of localized ventilation units were attached near the heads of both patients alongside the beds to capture, clean and release the captured exhaled air from the lying patients. When the bed...

Bed rest from the perspective of the high-risk pregnant woman.

Science.gov (United States)

Gupton, A; Heaman, M; Ashcroft, T

1997-01-01

To describe the experience of prolonged bed rest from the perspective of women during high-risk pregnancies. A focused ethnographic study that used interviews, participant diaries, and field notes as data sources. Participants were obtained from an acute-care hospital antepartum unit and an antepartum home care program. Twenty-four women with complications of pregnancy requiring prolonged bed rest (range, 7-50 days). A model of the stress process in pregnant women on bed rest emerged from the data analysis. Stressors were grouped into situational (sick role, lack of control, uncertainty, concerns regarding fetus's well-being, and being tired of waiting), environmental (feeling like a prisoner, being bored, and having a sense of missing out), and family (role reversal and worry about older children) categories. Two main mediators of stress were social support and coping. Families, friends, and professionals were perceived as sources of support. Women used coping strategies, such as keeping a positive attitude, taking it 1 day at a time, doing it for the baby, getting used to it, setting goals, and keeping busy. Manifestations of stress were evidenced by adverse physical symptoms, emotional reactions, and altered social relationships. Prolonged bed rest is a stressful experience for pregnant women at high risk. Understanding the stress process in pregnant women confined to bed rest may assist nurses in developing interventions to reduce stressors and enhance mediators.

Scour at the head of a vertical-wall breakwater

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Fredsøe, Jørgen

1997-01-01

This paper presents the results of an experimental investigation on the near-bed flow patterns, the bed shear stress amplification and scour around the head of a vertical-wall breakwater, using regular waves. The Keulegan-Carpenter number (KC), based on the diameter of the breakwater head, is found...

Physiological and Functional Alterations after Spaceflight and Bed Rest.

Science.gov (United States)

Mulavara, Ajitkumar P; Peters, Brian T; Miller, Chris A; Kofman, Igor S; Reschke, Millard F; Taylor, Laura C; Lawrence, Emily L; Wood, Scott J; Laurie, Steven S; Lee, Stuart M C; Buxton, Roxanne E; May-Phillips, Tiffany R; Stenger, Michael B; Ploutz-Snyder, Lori L; Ryder, Jeffrey W; Feiveson, Alan H; Bloomberg, Jacob J

2018-04-03

Exposure to microgravity causes alterations in multiple physiological systems, potentially impacting the ability of astronauts to perform critical mission tasks. The goal of this study was to determine the effects of spaceflight on functional task performance and to identify the key physiological factors contributing to their deficits. A test battery comprised of 7 functional tests and 15 physiological measures was used to investigate the sensorimotor, cardiovascular and neuromuscular adaptations to spaceflight. Astronauts were tested before and after 6-month spaceflights. Subjects were also tested before and after 70 days of 6° head-down bed rest, a spaceflight analog, to examine the role of axial body unloading on the spaceflight results. These subjects included Control and Exercise groups to examine the effects of exercise during bed rest. Spaceflight subjects showed the greatest decrement in performance during functional tasks that required the greatest demand for dynamic control of postural equilibrium which was paralleled by similar decrements in sensorimotor tests that assessed postural and dynamic gait control. Other changes included reduced lower limb muscle performance and increased heart rate to maintain blood pressure. Exercise performed during bed rest prevented detrimental change in neuromuscular and cardiovascular function, however, both bed rest groups experienced functional and balance deficits similar to spaceflight subjects. Bed rest data indicates that body support unloading experienced during spaceflight contributes to postflight postural control dysfunction. Further, the bed rest results in the Exercise group of subjects confirm that resistance and aerobic exercises performed during spaceflight can play an integral role in maintaining neuromuscular and cardiovascular function, which can help in reducing decrements in functional performance. These results indicate that a countermeasure to mitigate postflight postural control dysfunction is

[Pathophysiology of prolonged hypokinesia].

Science.gov (United States)

Kovalenko, E A

1976-01-01

Hypokinesia is an important problem in modern medicine. In the pathogenetic effect of prolonged hypokinesia the main etiological factor is diminished motor activity; of major importance are disorders in the energy and plastic metabolism which affect the muscle system; the contributing factors are cardiovascular deconditioning and orthostatic intolerance. This is attributed to a decreased oxygen supply and eliminated hydrostatic influences during a prolonged recumbency. Blood redistribution in the vascular bed is related to the Gauer-Henry reflex and subsequent changes in the fluid-electrolyte balance. Decreased load on the bone system induces changes in the protein-phosphate-calcium metabolism, diminished bone density and increased calcium content in the blood and urine. Changes in the calcium metabolism are systemic. The activity of the higher nervous system and reflex functions is lowered. Changes in the function of the autonomic nervous system which include a noticeable decline of its adaptive-trophic role as a result of the decrease of afferent and efferent impulsation are of great importance. Changes in the hormonal function involve a peculiar stress-reaction which develops at an early stage of hypokinesia as a response to an unusual situation. Prolonged hypokinesia may result in a disturbed function of the pituitary-adrenal system. It is assumed that prolonged hypokinesia may induce a specific disease of hypokinesia during which man cannot lead a normal mode of life and work.

Energy and rice quality aspects during drying of freshly harvested paddy with industrial inclined bed dryer

International Nuclear Information System (INIS)

Sarker, M.S.H.; Ibrahim, M. Nordin; Ab. Aziz, N.; Mohd. Salleh, P.

2014-01-01

Highlights: • We presented performance evaluation approach for industrial inclined bed paddy dryer. • Specific electrical energy consumption was 1.44–1.95 MJ/kg water evaporated. • Specific thermal energy consumption was 2.77–3.47 MJ/kg water evaporated. • Dryer yielded 1–4% higher head rice at drying temperature of 38–39 °C than 41–42 °C. • Dryers should be operated at 38–39 °C for 1–4% higher head rice at reasonable energy. - Abstract: The performance evaluation of any industrial dryer regarding energy consumption and product quality should be assessed to check its present status and to suggest for further efficient operation. An investigation was carried out to evaluate the impact of drying temperature and air flow on energy consumption and quality of rice during paddy drying with industrial inclined bed dryer (IBD) with average holding capacity of 15 ton in the selected complexes of Padiberas Nasional Berhad (BERNAS)-the national paddy custodian of Malaysia. In reducing paddy moisture content (mc) from 22% to 23% wet basis (wb) down to around 12.5% wb, the final mc, the specific electrical (in terms of primary energy) and the specific thermal energy consumption were found to be varied between 1.44 to 1.95 MJ/kg water evaporated and 2.77 to 3.47 MJ/kg water evaporated, respectively. Analysis revealed that the specific electrical energy consumption was around 20% lesser and the specific thermal energy consumption of IBDs was around 10% higher during drying with air temperature of 41–42 °C than drying with 38–39 °C in reducing paddy mc from 22% to 23% (wb) down to around 12.5% (wb). However, paddy being with almost same initial mc dried using drying temperature of 38–39 °C, IBDs yielded 1–4% higher head rice yield while milling recovery and whiteness were comparable at acceptable milling degree and transparency. The bed air flows between 0.27 and 0.29 m 3 m −2 s −1 resulted in higher head rice yield slightly while its

The relationship between bedding and face-down death in infancy: mathematical analysis of a respiratory simulation system using an infant mannequin to assess gas diffusibility in bedding.

Science.gov (United States)

Sakai, Jun; Funayama, Masato; Kanetake, Jun

2007-02-14

Rebreathing is a model for the relationship between a prone sleeping position and sudden infant death syndrome. This study used a mechanical simulation model to establish the relationship between types of bedding and rebreathing potential for an infant placed prone (face down) at different postnatal ages. The infant mannequin was connected to a respirator set to deliver physiologically appropriate combinations of tidal volume (V(T)) and respiratory rates (RR) across a range of postnatal ages (0-18 months). Before measurements were made, CO(2) flow was regulated to 5+/-0.1% of end-tidal PCO(2) (EtCO(2)). After the model was placed in a prone position, any increase in the fractional concentration of inspired CO(2) (FiCO(2)) was measured. FiCO(2) increased immediately and rapidly, and reached a maximum value within a few minutes. The maximum FiCO(2) ranged from under 2% to over 10%, depending on the bedding. FiCO(2) was also affected by V(T) and RR. This model is not applicable to actual infants because of the large tissue stores of CO(2) in infants; however, it is useful for evaluation of gas diffusibility of bedding and will simplify the investigation of sleeping environments when a baby is found dead with its face covered by soft bedding. In general, the higher the FiCO(2), the greater the rebreathing potential. Theoretically, considering the paucity of body stores of O(2), changes in FiO(2) would be affected not by changes in FiCO(2), but by CO(2) production and gas movement around the infant's face. The rapid decrease of FiO(2) is approximated at the inverse of the FiCO(2) timecourse, suggesting the significance of not only CO(2) accumulation but also O(2) deprivation in the potential space around the baby's face.

The Prolonged Neonatal Admission: Implications for our National Children's Hospital

LENUS (Irish Health Repository)

McGlacken-Byrne, SM

2016-06-01

A significant number of neonates are admitted to tertiary paediatric units for prolonged stays annually, despite limited availability of neonatal beds. As the three Dublin paediatric hospitals merge, this pressure will be transferred to our new National Children’s Hospital.\\r\

Diagnostic Role of Head-Bending and Lying-Down Tests in Lateral Canal Benign Paroxysmal Positional Vertigo.

Science.gov (United States)

Yetiser, Sertac; Ince, Dilay

2015-08-01

To compare the diagnostic value of the head-bending test (HBT), lying-down positioning test (LDPT) and patient's report to identify the affected canal in video-nystagmographically (VNG) confirmed patients with lateral canal benign paroxysmal positional vertigo (LC-BPPV). Case series with chart review. Head-bending, lying-down positioning and the head-roll maneuver (HRM) under VNG guidance. The data were collected in a referral community hospital. Seventy-eight patients (32 apogeotropic and 46 geotropic nystagmus) with LC-BPPV who had been recruited between 2009 and 2013 were enrolled in the study. Patients were tested with the HRM and then were asked about subjectively worse side. Later, they were subjected to HBT when sitting and the LDPT. The results were compared and studied with the 1-way ANOVA and chi-square tests. Statistical significance was set at p < 0.05. Affected side was identified by HRM in 75% of patients with apogeotropic nystagmus and 95.6% of patients with geotropic nystagmus. Approximately 65.6% of patients with apogeotropic and 52% of patients with geotropic nystagmus had nystagmus during LDPT. However, its comparability with HRM was low. However, treatment plan based on LDPT results alone provided relief of symptoms in additional 12.5% of patients with apogeotropic and in 2.2% of patients with geotropic nystagmus. Approximately 63% of patients with apogeotropic and 56% of patients with geotropic nystagmus were able to tell the worse side. Nystagmus comparable with HRM during HBT was low and not diagnostic. HRM has the greatest diagnostic value of positioning tests in LC-BPPV in this study. LDPT provides some contribution in the diagnosis of LC-BPPV but much less than HRM. Patients' subjective feeling of vertigo was also a useful test. However, HBT was not as sensitive as other measures in uncertain cases.

Cerebral vasoreactivity in response to a head-of-bed position change is altered in patients with moderate and severe obstructive sleep apnea.

Science.gov (United States)

Gregori-Pla, Clara; Cotta, Gianluca; Blanco, Igor; Zirak, Peyman; Giovannella, Martina; Mola, Anna; Fortuna, Ana; Durduran, Turgut; Mayos, Mercedes

2018-01-01

Obstructive sleep apnea (OSA) can impair cerebral vasoreactivity and is associated with an increased risk of cerebrovascular disease. Unfortunately, an easy-to-use, non-invasive, portable monitor of cerebral vasoreactivity does not exist. Therefore, we have evaluated the use of near-infrared diffuse correlation spectroscopy to measure the microvascular cerebral blood flow (CBF) response to a mild head-of-bed position change as a biomarker for the evaluation of cerebral vasoreactivity alteration due to chronic OSA. Furthermore, we have monitored the effect of two years of continuous positive airway pressure (CPAP) treatment on the cerebral vasoreactivity. CBF was measured at different head-of-bed position changes (supine to 30° to supine) in sixty-eight patients with OSA grouped according to severity (forty moderate to severe, twenty-eight mild) and in fourteen control subjects without OSA. A subgroup (n = 13) with severe OSA was measured again after two years of CPAP treatment. All patients and controls showed a similar CBF response after changing position from supine to 30° (p = 0.819), with a median (confidence interval) change of -17.5 (-10.3, -22.9)%. However, when being tilted back to the supine position, while the control group (p = 0.091) and the mild patients with OSA (p = 0.227) recovered to the initial baseline, patients with moderate and severe OSA did not recover to the baseline (9.8 (0.8, 12.9)%, p < 0.001) suggesting altered cerebral vasoreactivity. This alteration was correlated with OSA severity defined by the apnea-hypopnea index, and with mean nocturnal arterial oxygen saturation. The CBF response was normalized after two years of CPAP treatment upon follow-up measurements. In conclusion, microvascular CBF response to a head-of-bed challenge measured by diffuse correlation spectroscopy suggests that moderate and severe patients with OSA have altered cerebral vasoreactivity related to OSA severity. This may normalize after two years of CPAP

The effect of head-down tilt and water immersion on intracranial pressure in nonhuman primates

Science.gov (United States)

Keil, Lanny C.; Mckeever, Kenneth H.; Skidmore, Michael G.; Hines, John; Severs, Walter B.

1992-01-01

Intracranial pressure (ICP) is investigated in primates during and after -6-deg head-down tilt (HDT) and immersion in water to examine the effects of the headward fluid shift related to spaceflight. Following the HDT the primates are subjected to head-out thermoneutral water immersion, and the ICP is subsequently measured. ICP is found to increase from 3.8 +/- 1.1 to 5.3 +/- 1.3 mm Hg during the horizontal control period. ICP stabilizes at -6.3 +/- 1.3 mm Hg and then increases to -2.2 +/- 1.9 mm Hg during partial immersion, and ICP subsequently returns to preimmersion levels after immersion. These data indicate that exposure to HDT or water immersion lead to an early sharp increase in ICP, and water immersion alone leads to higher ICP levels. A significant conclusion of the work is that the ICP did not approach pathological levels, and this finding is relevant to human spaceflight research.

A short term -12° head down tilt does not mimic microgravity in terms of human gonadal function

Science.gov (United States)

Strollo, Felice; Pecorelli, Lia; Strollo, Giovanna; Morè, Massimo; Riondino, Giuseppe; Masini, Maria Angela; Uva, Bianca Maria

2006-09-01

A significant reversible decrease in testosterone (T) has been associated with microgravity in male rodents and humans. Urinary T excretion increases in primates under hypergravity. Hypogonadism is somehow related to abnormally high levels of leptin (L), a hormone produced by the adipose tissue which has been found to increase under microgravity simulation conditions like head down bed rest (HDBR). The aim of this study was to assess hemodynamic and pituitary-adrenal and -gonadal adaptation to an acute HDBR test to be eventually used on a routine basis to get better prepared to next space flights. The Authors performed a 1 hour -12° HDBR in 6 male and 6 female volunteers who underwent heart rate and blood pressure measurement together with a blood draw three times at 30 min intervals from the start to the end of the test for L, T, estradiol (E2), LH, androstenedione (A), cortisol (F), ACTH. 12 age- and sexmatched control subjects followed the same protocol except for keeping the sitting position all the time. According to the ANOVA for repeated measures, no changes occurred in L, T, E2 or LH whereas A, F and ACTH significantly decreased independently of gender. During HDBR systolic blood pressure decreased in both genders, diastolic blood pressure decreased significantly only in men and HR showed a more clear-cut decrease in women than in men. As a conclusion, such an acute steep-slope HDBR protocol may be efficiently used to testing immediate individual haemodynamic or adrenal response to microgravity but is not suitable for studies concerning gonadal adaptation.

Magnetic resonance imaging of the femoral head necrosis

Energy Technology Data Exchange (ETDEWEB)

Narita, Shinya; Asada, Kanji; Yoshida, Kenjiro and others

1986-06-01

Ten patients with avascular femoral head necrosis and four normal adults were examined by magnetic resonance imaging (MRI). In addition, the relationship between MRI and pathophysiology of three operated-on avascular femoral heads was evaluated. The medullary cavities of the normal femoral heads had a strong signal intensity on the saturation recovery (SR) image due to fat marrow, and the T/sub 1/ relaxation time was 160 +- 11 msec. In avascular femoral head necrosis, the necrotic area had a low signal intensity on the SR image and a prolonged T/sub 1/ relaxation time, while the reactive fibrous area had more prolonged T/sub 1/ relaxation time. For these reasons, MRI was found to show the pathological changes of avascular femoral head necrosis and can be expected to be useful for making early diagnoses and operation planning.

Magnetic resonance imaging of the femoral head necrosis

International Nuclear Information System (INIS)

Narita, Shinya; Asada, Kanji; Yoshida, Kenjiro

1986-01-01

Ten patients with avascular femoral head necrosis and four normal adults were examined by magnetic resonance imaging (MRI). In addition, the relationship between MRI and pathophysiology of three operated-on avascular femoral heads was evaluated. The medullary cavities of the normal femoral heads had a strong signal intensity on the saturation recovery (SR) image due to fat marrow, and the T 1 relaxation time was 160 ± 11 msec. In avascular femoral head necrosis, the necrotic area had a low signal intensity on the SR image and a prolonged T 1 relaxation time, while the reactive fibrous area had more prolonged T 1 relaxation time. For these reasons, MRI was found to show the pathological changes of avascular femoral head necrosis and can be expected to be useful for making early diagnoses and operation planning. (author)

Exercise Effects on the Course of Gray Matter Changes Over 70 Days of Bed Rest

Science.gov (United States)

Koppelmans, V.; Ploutz-Snyder, L.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Seidler, R. D.

2014-01-01

Long duration spaceflight affects posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes through direct effects on peripheral changes that result from reduced vestibular stimulation and body unloading. Effects of microgravity on sensorimotor function have been investigated on earth using bed rest studies. Long duration bed rest serves as a space-flight analogue because it mimics microgravity in body unloading and bodily fluid shifts. It has been hypothesized that the cephalad fluid shift that has been observed in microgravity could potentially affect central nervous system function and structure, and thereby indirectly affect sensorimotor or cognitive functioning. Preliminary results of one of our ongoing studies indeed showed that 70 days of long duration head down-tilt bed rest results in focal changes in gray matter volume from pre-bed rest to various time points during bed rest. These gray matter changes that could reflect fluid shifts as well as neuroplasticity were related to decrements in motor skills such as maintenance of equilibrium. In consideration of the health and performance of crewmembers both inand post-flight we are currently conducting a study that investigates the potential preventive effects of exercise on gray matter and motor performance changes that we observed over the course of bed rest. Numerous studies have shown beneficial effects of aerobic exercise on brain structure and cognitive performance in healthy and demented subjects over a large age range. We therefore hypothesized that an exercise intervention in bed rest could potentially mitigate or prevent the effects of bed rest on the central nervous system. Here we present preliminary outcomes of our study.

Periodic upright posture negates the suppression of neuroendocrine response to head down bedrest

Science.gov (United States)

Wade, C. E.; Vernikos, J.; Evans, J.; Ohara, D.

1992-01-01

Head down bedrest (HDT) decreases plasma neurohormone levels, attaining a nadir within four hours. The present study evaluates the effect of periodic standing or exercises (+G(z)) on this acute suppression of plasma neurohormones. Methods: Nine male subjects (mean plus or minus SE age 37 plus or minus 2 yr; height 182 plus or minus 2 cm; weight 83 plus or minus 3 kg) were admitted to the Human Research Facility on three occasions separated by one month. Subjects were assigned to head down tilt (minus 6 degrees) or 15-minutes of standing or moderate exercise at the end of each hour. Initially during an ambulatory period, subjects were placed in a supine position for 45-min and a control blood sample obtained. The next day following 4 hours of HDT with or without standing or exercise a blood sample was taken 45-min (3 3/4 hours into HDT) after the preceding stand or exercise. Blood was withdrawn and all plasma samples frozen for determination of neurohormone levels within the same assay. Plasma aldosterone, Plasma Renin Activity (PRA) vasopressin (AVP) and cortisol levels were measured by radioimmunoassay. Norepinephrine (NE) and epinephrine (E) levels were measured by electrochemical detection following HPLC. Values were compared by ANOVA, P less than 0.05. Results: Control levels following 45-min supine were not different between treatments. HDT suppressed plasma aldosterone (13.9 plus or minus 3.7 to 6.6 plus or minus 0.7 ng/dl) and NE levels (299 plus or minus 35 to 217 plus or minus 23 pg/dl), E (69 plus or minus 15 to 65 plus or minus 21 pg/ml), and PRA (0.64 plus or minus 0.13 to 0.58 plus or minus 0.17 ngAl/m/hr) were not significantly altered. Standing or exercise negated the decrease in aldosterone and NE levels due to HDT. Conclusions: Periodic upright posture (+G(z)) with or without exercise for 15-min out of each hour negates the acute suppression of aldosterone and NE associated with HDT.

Effects of bedding quality on lying behavior of dairy cows.

Science.gov (United States)

Fregonesi, J A; Veira, D M; von Keyserlingk, M A G; Weary, D M

2007-12-01

Cows prefer to spend more time lying down in free stalls with more bedding, but no research to date has addressed the effects of bedding quality. Bedding in stalls often becomes wet either from exposure to the elements or from feces and urine. The aim of this study was to test the effect of wet bedding on stall preference and use. Four groups of 6 nonlactating Holstein cows were housed in free stalls bedded daily with approximately 0.1 m of fresh sawdust. Following a 5-d adaptation period, each group of cows was tested sequentially with access to stalls with either dry or wet sawdust bedding (86.4 +/- 2.1 vs. 26.5 +/- 2.1% dry matter), each for 2 d. These no-choice phases were followed by a 2-d free-choice phase during which cows had simultaneous access to stalls containing either wet or dry bedding. Stall usage was assessed by using 24-h video recordings scanned at 10-min intervals, and responses were analyzed by using a mixed model, with group (n = 4) as the observational unit. The minimum and maximum environmental temperatures during the experiment were 3.4 +/- 2.2 and 6.8 +/- 2.5 degrees C, respectively. When cows had access only to stalls with wet bedding, they spent 8.8 +/- 0.8 h/d lying down, which increased to 13.8 +/- 0.8 h/d when stalls with dry bedding were provided. Cows spent more time standing with their front 2 hooves in the stall when provided with wet vs. dry bedding (92 +/- 10 vs. 32 +/- 10 min/d). During the free-choice phase, all cows spent more time lying down in the dry stalls, spending 12.5 +/- 0.3 h/d in the dry stalls vs. 0.9 +/- 0.3 h/ d in stalls with wet bedding. In conclusion, dairy cows show a clear preference for a dry lying surface, and they spend much more time standing outside the stall when only wet bedding is available.

High Intensity Exercise Countermeasures does not Prevent Orthostatic Intolerance Following Prolonged Bed Rest

Science.gov (United States)

Platts, Steven H.; Stenger, Michael B.; Ploutz-Snyder, Lori L.; Lee, Stuart M. C.

2014-01-01

Approximately 20% of Space Shuttle astronauts became presyncopal during operational stand and 80deg head-up tilt tests, and the prevalence of orthostatic intolerance increases after longer missions. Greater than 60% of the US astronauts participating in Mir and early International Space Station missions experienced presyncope during post-flight tilt tests, perhaps related to limitations of the exercise hardware that prevented high intensity exercise training until later ISS missions. The objective of this study was to determine whether an intense resistive and aerobic exercise countermeasure program designed to prevent cardiovascular and musculoskeletal deconditioning during 70 d of bed rest (BR), a space flight analog, would protect against post-BR orthostatic intolerance. METHODS Twenty-six subjects were randomly assigned to one of three groups: non-exercise controls (n=11) or one of two exercise groups (ExA, n=8; ExB, n=7). Both ExA and ExB groups performed the same resistive and aerobic exercise countermeasures during BR, but one exercise group received testosterone supplementation while the other received a placebo during BR in a double-blinded fashion. On 3 d/wk, subjects performed lower body resistive exercise and 30 min of continuous aerobic exercise (=75% max heart rate). On the other 3 d/wk, subjects performed only highintensity, interval-style aerobic exercise. Orthostatic intolerance was assessed using a 15-min 80? head-up tilt test performed 2 d (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using carbon monoxide rebreathing on BR-3 and before rising on the first recovery day (BR+0). The code for the exercise groups has not been broken, and results are reported here without group identification. RESULTS Only one subject became presyncopal during tilt testing on BR-2, but 7 of 11 (63%) controls, 3 of 8 (38%) ExA, and 4 of 7 (57%) ExB subjects were presyncopal on BR70. Survival analysis of post-BR tilt tests revealed no

Experimental results on the coolability of a debris bed with multidimensional cooling effects

International Nuclear Information System (INIS)

Rashid, M.; Kulenovic, R.; Laurien, E.; Nayak, A.K.

2011-01-01

Research highlights: ► Performing of dryout experiments with a polydispersed bed for top- and bottom-flooding. ► Study of influence of different down comer configurations on the coolability of debris bed. ► Measurement of temperature profiles, pressure drops and determination of dryout heat flux. ► Observation of noticeable increase in coolability of debris bed with the use of down comer is observed. - Abstract: Within the reactor safety research, the removal of decay heat from a debris bed (formed from corium and residual water) is of great importance. In order to investigate experimentally the long term coolability of debris beds, the scaled test facility “DEBRIS” (Fig. 1) has been built at IKE. A large number of experiments had been carried out to investigate the coolability limits for different bed configurations (). Analyses based on one-dimensional configurations underestimate the coolability in realistic multidimensional configurations, where lateral water access and water inflow via bottom regions are favoured. Following the experiments with top- and bottom-flooding flow conditions this paper presents experimental results of boiling and dryout tests at different system pressures based on top- and bottom-flooding via a down comer configuration. A down comer with an internal diameter of 10 mm has been installed at the centre of the debris bed. The debris bed is built up in a cylindrical crucible with an inner diameter of 125 mm. The bed of height 640 mm is composed of polydispersed particles with particle diameters 2, 3 and 6 mm. Since the long term coolability of such particle bed is limited by the availability of coolant inside the bed and not by heat transfer limitations from the particles to the coolant, the bottom inflow of water improves the coolability of the debris bed and an increase of the dryout heat flux can be observed. With increasing system pressure, the coolability limits are enhanced (increased dryout heat flux).

Variation of stream power with seepage in sand-bed channels

African Journals Online (AJOL)

2009-12-27

Dec 27, 2009 ... Keywords: friction slope, seepage, sediment transport, stream power, suction ... particles from the bed and on further movement of the bed load is of great ..... KNIGHTON AD (1987) River channel adjustment – the down stream.

Modeling of flow conditions in down draft gasifiers using tin film models

DEFF Research Database (Denmark)

Jensen, Torben Kvist; Gøbel, Benny; Henriksen, Ulrik Birk

2003-01-01

In order to examine how an inhomogeneous char bed affects the gas flow through the bed, a dynamic model have been developed to describe the flow distribution in a down draft gasifier. The gas flow distribution through the bed was determined using a thin film model approach. The temperatures...

Changes in Cartilage Morphology of the Knee after 14-days of Bed Rest

Science.gov (United States)

Liphardt, A.-M.; Mündermann, A.; Koo, S.; Bäcker, N.; Andriacchi, T.; Zange, J.; Mester, J.; Heer, M.

Introduction While there are still many unanswered questions related to the effects of space flight and disuse on cartilage health and cartilage morphology the number of in vivo experiments in humans is small For muscle and bone tissue it is well known that unloading results in degeneration of those tissues Also for cartilage previous studies in patients suggest that unloading causes cartilage degeneration Studies using immobilization as a model of unloading help to investigate the importance of experiencing mechanical loads for the maintenance of healthy biological tissues The goal of our study was to investigate whether bed rest induced immobilization has a negative effect on articular cartilage in healthy subjects and if vibration training is a potential counter-measure for these negative effects Methods Eight male healthy subjects 78 1 pm 9 5 kg 179 pm 9 6 cm 26 pm 5 years performed a 14-day bed rest in 6 r -head down tilt HDT The study was designed in a cross-over-design where each subject received a training intervention vib in one phase and no intervention con in the other phase During the training intervention subjects trained 2 x 5-minutes per day at 20 Hz with 2 -- 4 mm amplitude on a vibration plate Galileo 900 Magnet resonance MR imaging of the right knee was performed to measure articular cartilage thickness MR-images 2 mm slice thickness 0 35 mm x 0 35 mm in-plane resolution 448 x 512 pixels were taken before and after bed rest to investigate the effects of bed rest

Risks predicting prolonged hospital discharge boarding in a regional acute care hospital.

Science.gov (United States)

Shaikh, Sajid A; Robinson, Richard D; Cheeti, Radhika; Rath, Shyamanand; Cowden, Chad D; Rosinia, Frank; Zenarosa, Nestor R; Wang, Hao

2018-01-30

Prolonged hospital discharge boarding can impact patient flow resulting in upstream Emergency Department crowding. We aim to determine the risks predicting prolonged hospital discharge boarding and their direct and indirect effects on patient flow. Retrospective review of a single hospital discharge database was conducted. Variables including type of disposition, disposition boarding time, case management consultation, discharge medications prescriptions, severity of illness, and patient homeless status were analyzed in a multivariate logistic regression model. Hospital charges, potential savings of hospital bed hours, and whether detailed discharge instructions provided adequate explanations to patients were also analyzed. A total of 11,527 admissions was entered into final analysis. The median discharge boarding time was approximately 2 h. Adjusted Odds Ratio (AOR) of patients transferring to other hospitals was 7.45 (95% CI 5.35-10.37), to court or law enforcement custody was 2.51 (95% CI 1.84-3.42), and to a skilled nursing facility was 2.48 (95% CI 2.10-2.93). AOR was 0.57 (95% CI 0.47-0.71) if the disposition order was placed during normal office hours (0800-1700). AOR of early case management consultation was 1.52 (95% CI 1.37-1.68) versus 1.73 (95% CI 1.03-2.89) for late consultation. Eighty-eight percent of patients experiencing discharge boarding times within 2 h of disposition expressed positive responses when questioned about the quality of explanations of discharge instructions and follow-up plans based on satisfaction surveys. Similar results (86% positive response) were noted among patients whose discharge boarding times were prolonged (> 2 h, p = 0.44). An average charge of $6/bed/h was noted in all hospital discharges. Maximizing early discharge boarding (≤ 2 h) would have resulted in 16,376 hospital bed hours saved thereby averting $98,256.00 in unnecessary dwell time charges in this study population alone. Type of disposition, case

Use of bed nets and factors that influence bed net use among Jinuo Ethnic Minority in southern China.

Science.gov (United States)

Xu, Jian-wei; Liao, Yuan-mei; Liu, Hui; Nie, Ren-hua; Havumaki, Joshua

2014-01-01

Insecticide-treated nets (ITNs) are an integral part of vector control recommendations for malaria elimination in China. This study investigated the extent to which bed nets were used and which factors influence bed net use among Jinuo Ethnic Minority in China-Myanmar-Laos border areas. This study combined a quantitative household questionnaire survey and qualitative semi-structured in-depth interviews (SDI). Questionnaires were administered to 352 heads of households. SDIs were given to 20 key informants. The bed net to person ratio was 1∶2.1 (i.e., nearly one net for every two people), however only 169 (48.0%) households owned at least one net and 623 (47.2%) residents slept under bed nets the prior night. The percentages of residents who regularly slept under nets (RSUN) and slept under nets the prior night (SUNPN) were similar (48.0% vs. 47.2%, P>0.05), however the percentage correct use of nets (CUN) was significantly lower (34.5%, Pcash income per person (ACIP) was an independent factor that influenced bed net use (PHigh bed net availability does not necessarily mean higher coverage or bed net use. Household income, house type and knowledge of the ability of bed nets to prevent malaria are all independent factors that influence bed net use among Jinuo Ethnic Minority.

Head of the bed elevation angle recorder for intensive care unit

Science.gov (United States)

Krefft, Maciej; Zamaro-Michalska, Aleksandra; Zabołotny, Wojciech M.; Zaworski, Wojciech; Grzanka, Antoni; Łazowski, Tomasz; Tavola, Mario; Siewiera, Jacek; Mikaszewska-Sokolewicz, Małgorzata

2013-10-01

This paper presents a recording system optimized for long term measurement of bed headrest elevation angle in the Intensive Care Unit. The continuous monitoring of this parameter allows to find the correlation between the patient's position in bed and the risk of the Ventilator Associated Pneumonia (VAP), a very serious problem in therapy of critically ill patients. Recorder might be be an important tool to evaluate the "care bundles" - sets of preventive procedures recommended for treatment of patients in the ICU.

Comparison of Ocular Outcomes in Two 14-Day Bed Rest Studies

Science.gov (United States)

Cromwell, R. L.; Zanello, S. B.; Yarbough, P. O.; Taibbi, G.; Vizzeri, G.

2011-01-01

Reports of astronauts visual changes raised concern about ocular health during long-duration spaceflight. Some of these findings included hyperopic shifts, choroidal folds, optic disc edema, retinal nerve fiber layer (RNFL) thickening, and cotton wool spots. While the etiology remains unknown, hypotheses speculate that hypertension in the brain caused by cephalad fluid shifts during spaceflight is a possible mechanism for these ocular changes. Head-down tilt (HDT) bed rest is a spaceflight analog that induces cephalad fluid shifts. In addition, previous studies of the HDT position demonstrated body fluid shifts associated with changes in intraocular pressure (IOP). For these reasons, vision monitoring of HDT bed rest subjects was implemented for NASA bed rest studies. Subjects selected for these studies were healthy adults (14 males and 5 females). Average age was 37.5 plus or minus 9.1 years, weight was 77.4 plus or minus 11.3 Kg, and height was 173.4 plus or minus 7.2 14 cm. Controlled conditions followed for all NASA bed rest studies were implemented. These conditions included factors such as eating a standardized diet, maintaining a strict sleep wake cycle, and remaining in bed for 24 hours each day. In one study, subjects maintained a horizontal (0 degree) position while in bed and were exercised six days per week with an integrated resistance and aerobic training (iRAT) program. In the other study, subjects were placed at 6 degrees HDT while in bed and did not engage in exercise. All subjects underwent pre- and post bed rest vision testing. While the battery of vision tests for each study was not identical, measures common to both studies will be presented. These measures included IOP and measures that provided an indication of optic disc swelling as derived from optical coherence tomography (OCT) testing: average retinal nerve fiber layer (RNFL) thickness (millimeters), disc area (square millimeters), rim area (square millimters), and average cup to disc (C

Laryngotracheal Injury following Prolonged Endotracheal Intubation

Directory of Open Access Journals (Sweden)

J. Mehdizadeh

2006-07-01

Full Text Available Background: Prolonged endotracheal intubation is a growing method for supporting ventilation in patients who require intensive care. Despite considerable advancement in endotracheal intubation, this method still has some complications; the most important is laryngo-tracheal injuries. Methods: Over a 2-year period, this retrospective study was conducted on 57 patients with history of prolonged intubation who were referred to the ENT Department of Amir Alam Hospital. For each patient, a complete evaluation including history, physical examination, and direct laryngoscopy and bronchoscopy was done under general anesthesia. Results: Fifty-seven patients (44 male; mean age, 23.014.7 years were studied. Mean intubation period was 15.88 days. The most common presenting symptom was dyspnea (62%. Head trauma was responsible for most cases of intubation (72.4%. The most common types of tracheal and laryngeal lesions were tracheal (56.9% and subglottic (55.2% stenosis, respectively. Mean length of tracheal stenosis was 0.810.83 cm. There was a statistically significant relationship between length of tracheal stenosis and intubation period (P=0.0001 but no relation was observed between tracheal stenosis and age, sex, and etiology of intubation (All P=NS. Among the glottic lesions, inter- arytenoids adhesion was the most common lesion (25.9%. No statistically significant relation was found between glottic and subglottic lesions and age, sex and intubation period (all P=NS. Length of stenosis and intubation period was significantly greater in tracheal/ subglottic lesions than those in glottic/ supraglottic lesions (all P=NS. Conclusion: After prolonged endotracheal intubation, laryngo-tracheal lesions had no relation with patient’s age, sex, and cause of intubation.There was direct relation between length of tracheal stenosis and intubation period. Glottic lesions were more commonly observed in head trauma patients. Lesion length and intubation

The rationale for sitting elderly patients in hospital out of bed for long periods is medically unsubstantiated and detrimental to their recovery.

Science.gov (United States)

Bliss, Mary Rose

2004-01-01

The notorious statement by Asher about the dangers of bed rest [Brit Med J 1947; ii: 967-8] which continues to be quoted out of context in leading medical journals today is inapplicable to modern short stay elderly hospital patients and has little medical foundation. 'Blood clotting in the veins' is more likely to result from venous stasis during sitting than from lying down. 'Lime draining from the bones' refers to subjects' spending weeks, not hours, in the horizontal position and similar losses have been shown to occur in healthy people immobilised in chairs for long periods during the day. Constipation is common in sick old people and there is no evidence that 'scybala stacking up the colon' is more likely to occur in bed than in a chair. The 'flesh rotting from the seat', or pressure sores, occur as frequently or more frequently, in sick patients nursed in chairs as in bed. 'Urine leaking from the distended bladder' may be reduced in very debilitated old people sitting in chairs, but at the expense of impaired renal function associated with reduced perfusion in the upright posture and exacerbated incontinence due to a compensatory diuresis at night. The 'spirit evaporating from the soul' today is more likely to afflict old patients who are exhausted by prolonged chair nursing and orthostatic hypotension due to age or illness. Recent studies in intensive care patients have highlighted the hypotension due to vasodilatation which can occur in infection and trauma. There is no evidence that nosocomial pneumonia is reduced by sitting patients out of bed, and lack of sleep is likely to exacerbate infection and delay recovery. Preventing patients from lying down when they feel the need is a violation of their rights and has been shown to be probably as injurious as the Victorian practice of preventing healthy patients from getting up. Physiotherapy is obviously important but patients should be allowed to decide for themselves how long they spend in or out of bed.

Exploring the Early Structure of a Rapidly Decompressed Particle Bed

Science.gov (United States)

Zunino, Heather; Adrian, R. J.; Clarke, Amanda; Johnson, Blair; Arizona State University Collaboration

2017-11-01

Rapid expansion of dense, pressurized beds of fine particles subjected to rapid reduction of the external pressure is studied in a vertical shock tube. A near-sonic expansion wave impinges on the particle bed-gas interface and rapidly unloads the particle bed. A high-speed video camera captures events occurring during bed expansion. The particle bed does not expand homogeneously, but breaks down into horizontal slabs and then transforms into a cellular-type structure. There are several key parameters that affect the particle bed evolution, including particle size and initial bed height. Analyses of this bed structure evolution from experiments with varying particle sizes and initial bed heights is presented. This work is supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science and Academic Alliance Program, under Contract No. DE-NA0002378.

High dietary sodium chloride causes further protein loss during head-down tilt bed rest (HDBR)

Science.gov (United States)

Buehlmeier, Judith; Frings-Meuthen, Petra; Baecker, Natalie; Stehle, Peter; Heer, Martina

Human spaceflight is associated with a loss of body protein most likely caused by muscle degradation. Additionally astronauts tend towards a high dietary intake of sodium chloride (NaCl), which has recently been shown to induce low grade metabolic acidosis (Frings-Meuthen et al. JBMR, Epub 2007). In several patterns, e.g. chronical renal failure, metabolic acidosis is associated with protein catabolism. We therefore hypothesized that high dietary intake of NaCl enforces protein losses in HDBR, a model for physiological changes in microgravity (µG). Eight healthy male subjects (mean age 26.25 ± 3.5; mean body weight: 78.5 ± 4.1 kg) participated in a 14-day bed rest study in the metabolic ward of the DLR - Institute of Aerospace Medicine, Cologne, Germany. The study was carried out in a cross over design, consisting of two phases, each lasting 22 days (5 days adaptation, 14 days 6° HDBR and 3 days recovery). Both study phases were identical with respect to environmental conditions and study protocol. Subjects received an individually tailored, weight-maintaining diet containing 1.3 g protein/kg/day. The diet was identical in both study phases with the exception of NaClintake: Every subject received a low NaCl diet (0.7 mmol/kg/day) in one phase and a high NaCl diet (7.7 mmol/kg/day) in another one. Blood gas for analysis of acid-base balance was implemented at days 4 and 5 of adaptation, days 2, 5, 7, 10, 12, 14 of HDBR and days 2, 3 of recovery. Continuous urine collection started on the first day in the metabolic ward to analyze nitrogen excretion. Nitrogen balance was calculated from the difference between protein intake and urinary nitrogen excretion, determined by use of chemiluminescence (Grimble et al. JPEN, 1988). Plasma pH did not change significantly (p=0.285), but plasma bicarbonate and base excess decreased (p=0.0175; p=0.0093) with high NaCl intake in HDBR compared to the low NaCl diet. Nitrogen balance in HDBR was negative, as expected in

Biomass gasification in fixed bed type down draft: theoretical and experimental aspects; Gasificacao de biomassa em leito fixo tipo concorrente: aspectos teoricos e experimentais

Energy Technology Data Exchange (ETDEWEB)

Martinez, Juan Daniel; Andrade, Rubenildo Vieira; Lora, Electo Eduardo Silva [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Inst. de Engenharia Mecanica. Nucleo de Excelencia em Geracao Termeletrica e Distribuida

2008-07-01

Actually are recognizing the advantages of biomass in reducing dependence on fossil fuels and significant reduction in emissions of greenhouse effect gases such as Co2. Also are known the different conversion of biomass routes for their use or exploitation, such as thermochemical process (gasification, pyrolysis and combustion), the biological process (fermentation and transesterification) and the physical process (densification, reducing grain and mechanical pressing). In this sense, the gasification is regarded as the most promising mechanism to obtain a homogeneous gaseous fuel with sufficient quality in the small scale distributed generation. This work presents some aspects of biomass gasification in fixed bed, as well as some preliminary results in the evaluation and operation of fixed bed down draft gasifier with double stage air supply of the NEST, identifying the adequate air supply quantity (equivalence ratio in the range of 0,35 to 0,45) for obtaining a fuel gas with lower heating value around 4 MJ/N m3. (author)

Control of a nursing bed based on a hybrid brain-computer interface.

Science.gov (United States)

Nengneng Peng; Rui Zhang; Haihua Zeng; Fei Wang; Kai Li; Yuanqing Li; Xiaobin Zhuang

2016-08-01

In this paper, we propose an intelligent nursing bed system which is controlled by a hybrid brain-computer interface (BCI) involving steady-state visual evoked potential (SSVEP) and P300. Specifically, the hybrid BCI includes an asynchronous brain switch based on SSVEP and P300, and a P300-based BCI. The brain switch is used to turn on/off the control system of the electric nursing bed through idle/control state detection, whereas the P300-based BCI is for operating the nursing bed. At the beginning, the user may focus on one group of flashing buttons in the graphic user interface (GUI) of the brain switch, which can simultaneously evoke SSVEP and P300, to switch on the control system. Here, the combination of SSVEP and P300 is used for improving the performance of the brain switch. Next, the user can control the nursing bed using the P300-based BCI. The GUI of the P300-based BCI includes 10 flashing buttons, which correspond to 10 functional operations, namely, left-side up, left-side down, back up, back down, bedpan open, bedpan close, legs up, legs down, right-side up, and right-side down. For instance, he/she can focus on the flashing button "back up" in the GUI of the P300-based BCI to activate the corresponding control such that the nursing bed is adjusted up. Eight healthy subjects participated in our experiment, and obtained an average accuracy of 93.75% and an average false positive rate (FPR) of 0.15 event/min. The effectiveness of our system was thus demonstrated.

Severe bradycardia and prolonged hypotension in ciguatera.

Science.gov (United States)

Chan, Thomas Yan Keung

2013-06-01

Ciguatera results when ciguatoxin-contaminated coral reef fish from tropical or subtropical waters are consumed. The clinical features that present in affected persons are mainly gastrointestinal, neurological, general, and much less commonly, cardiovascular. We report the case of a 50-year-old man who developed the characteristic combination of acute gastrointestinal and neurological symptoms after the consumption of an unidentified coral reef fish head. In addition to those symptoms, he developed dizziness, severe bradycardia (46 bpm) and prolonged hypotension, which required the administration of intravenous atropine and over three days of intravenous fluid replacement with dopamine infusion. Patients with ciguatera can develop severe bradycardia and prolonged hypotension. Physicians should recognise the possible cardiovascular complications of ciguatera and promptly initiate treatment with intravenous atropine, intravenous fluid replacement and inotropic therapy if such complications are observed.

Feasibility Study of a Lunar Analog Bed Rest Model

Science.gov (United States)

Cromwell, Ronita L.; Platts, Steven H.; Yarbough, Patrice; Buccello-Stout, Regina

2010-01-01

The purpose of this study was to determine the feasibility of using a 9.5deg head-up tilt bed rest model to simulate the effects of the 1/6 g load to the human body that exists on the lunar surface. The lunar analog bed rest model utilized a modified hospital bed. The modifications included mounting the mattress on a sled that rolled on bearings to provide freedom of movement. The weight of the sled was off-loaded using a counterweight system to insure that 1/6 body weight was applied along the long axis (z-axis) of the body. Force was verified through use of a force plate mounted at the foot of the bed. A seating assembly was added to the bed to permit periods of sitting. Subjects alternated between standing and sitting positions throughout the day. A total of 35% of the day was spent in the standing position and 65% was spent sitting. In an effort to achieve physiologic fluid shifts expected for a 1/6 G environment, subjects wore compression stockings and performed unloaded foot and ankle exercises. Eight subjects (3 females and 5 males) participated in this study. Subjects spent 13 days in the pre-bed rest phase, 6 days in bed rest and 3 days post bed rest. Subjects consumed a standardized diet throughout the study. To determine feasibility, measures of subject comfort, force and plasma volume were collected. Subject comfort was assessed using a Likert scale. Subjects were asked to assess level of comfort (0-100) for 11 body regions and provide an overall rating. Results indicated minimal to no discomfort as most subjects reported scores of zero. Force measures were performed for each standing position and were validated against subject s calculated 1/6 body weight (r(sup 2) = 0.993). The carbon monoxide rebreathing technique was used to assess plasma volume during pre-bed rest and on the last day of bed rest. Plasma volume results indicated a significant decrease (p = 0.001) from pre to post bed rest values. Subjects lost on average 8.3% (sd = 6.1%) during the

Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men

Science.gov (United States)

Shaffer-Bailey, M.; Greenleaf, J. E.; Hutchinson, T. M.

1996-01-01

PURPOSE: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. METHODS: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degree.s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees.s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1+/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degree C) treatments. RESULTS: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54+/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml.6 h(-1)) was 28% greater (p strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees.s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (delta = -6%, p strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees.s(-1) and lighter (180 degrees.s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after Skylab flights to 84 d.

Allocation of Attention with Head-Up Displays

National Research Council Canada - National Science Library

Wickens, C

1998-01-01

Two experiments examined the effects of display location (head up vs. head down) and image intensity/clutter on flight path performance and mid-air target detection in a general aviation cruise flight environment...

A combination of whey protein and potassium bicarbonate supplements during head-down-tilt bed rest: Presentation of a multidisciplinary randomized controlled trial (MEP study)

Science.gov (United States)

Buehlmeier, Judith; Mulder, Edwin; Noppe, Alexandra; Frings-Meuthen, Petra; Angerer, Oliver; Rudwill, Floriane; Biolo, Gianni; Smith, Scott M.; Blanc, Stéphane; Heer, Martina

2014-02-01

Inactivity, as it appears during space flight and in bed rest, induces reduction of lean body and bone mass, glucose intolerance, and weakening of the cardiovascular system. Increased protein intake, whey protein in particular, has been proposed to counteract some of these effects, but has also been associated with negative effects on bone, likely caused by a correspondingly high ratio of acid to alkali precursors in the diet.

Stabilizing Effects of Bacterial Biofilms: EPS Penetration and Redistribution of Bed Stability Down the Sediment Profile

Science.gov (United States)

Chen, X. D.; Zhang, C. K.; Zhou, Z.; Gong, Z.; Zhou, J. J.; Tao, J. F.; Paterson, D. M.; Feng, Q.

2017-12-01

Biofilms, consisting of microorganisms and their secreted extracellular polymeric substances (EPSs), serve as "ecosystem engineers" stabilizing sedimentary environments. Natural sediment bed provides an excellent substratum for biofilm growth. The porous structure and rich nutrients allow the EPS matrix to spread deeper into the bed. A series of laboratory-controlled experiments were conducted to investigate sediment colonization of Bacillus subtilis and the penetration of EPS into the sediment bed with incubation time. In addition to EPS accumulation on the bed surface, EPS also penetrated downward. However, EPS distribution developed strong vertical heterogeneity with a much higher content in the surface layer than in the bottom layer. Scanning electron microscope images of vertical layers also displayed different micromorphological properties of sediment-EPS matrix. In addition, colloidal and bound EPSs exhibited distinctive distribution patterns. After the full incubation, the biosedimentary beds were eroded to test the variation of bed stability induced by biological effects. This research provides an important reference for the prediction of sediment transport and hence deepens the understanding of the biologically mediated sediment system and broadens the scope of the burgeoning research field of "biomorphodynamics."

Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

Science.gov (United States)

Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

1994-01-01

To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p < 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9* +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.5%, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

Knee-Joint Proprioception During 30-Day 6 deg Head-Down Bed Rest with Isotonic and Isokinetic Exercise Training

Science.gov (United States)

Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

1994-01-01

To determine if daily isotonic exercise or isokinetic exercise training coupled with daily log proprioceptive training, would influence log proprioceptive tracking responses during Bed Rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a NO-Exercise (NOE) training control group (n = 5), and IsoTanic Exercise (ITE, n = 7) and IsoKinetic Exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min period / d, 5 d /week. Only the IKE group performed proprioceptive training using a now isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pro-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p less than 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9 +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.50, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both lsotonic exercise training (without additional propriaceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

Arterial Pressure Gradients during Upright Posture and 30 deg Head Down Tilt

Science.gov (United States)

Sanchez, E. R; William, J. M.; Ueno, T.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

1997-01-01

Gravity alters local blood pressure within the body so that arterial pressures in the head and foot are lower and higher, respectively, than that at heart level. Furthermore, vascular responses to local alterations of arterial pressure are probably important to maintain orthostatic tolerance upon return to the Earth after space flight. However, it has been difficult to evaluate the body's arterial pressure gradient due to the lack of noninvasive technology. This study was therefore designed to investigate whether finger arterial pressure (FAP), measured noninvasively, follows a normal hydrostatic pressure gradient above and below heart level during upright posture and 30 deg head down tilt (HDT). Seven healthy subjects gave informed consent and were 19 to 52 years old with a height range of 158 to 181 cm. A Finapres device measured arterial pressure at different levels of the body by moving the hand from 36 cm below heart level (BH) to 72 cm above heart level (AH) in upright posture and from 36 cm BH to 48 cm AH during HDT in increments of 12 cm. Mean FAP creased by 85 mmHg transitioning from BH to AH in upright posture, and the pressure gradient calculated from hydrostatic pressure difference (rho(gh)) was 84 mmHg. In HDT, mean FAP decreased by 65 mmHg from BH to AH, and the calculated pressure gradient was also 65 mmHg. There was no significant difference between the measured FAP gradient and the calculated pressure gradient, although a significant (p = 0.023) offset was seen for absolute arterial pressure in upright posture. These results indicate that arterial pressure at various levels can be obtained from the blood pressure at heart level by calculating rho(gh) + an offset. The offset equals the difference between heart level and the site of measurement. In summary, we conclude that local blood pressure gradients can be measured by noninvasive studies of FAP.

Fluidized bed volume reduction of diverse radwastes

International Nuclear Information System (INIS)

McFee, J.N.; McConnell, J.W.; Waddoups, D.A.; Gray, M.F.; Harwood, L.E.; Clayton, N.J.; Drown, D.C.

1981-01-01

Method and apparatus for a fluidized bed radwaste volume reduction system are claimed. Low level radioactive wastes, combustible solids, ion exchange resins and filter sludges, and liquids, emanating from a reactor facility are introduced separately through an integrated waste influent system into a common fluidized bed vessel where volume reduction either through incineration or calcination occurs. Addition of a substance to the ion exchange resin before incineration inhibits the formation of low-melting point materials which tend to form clinkers in the bed. Solid particles are scrubbed or otherwise removed from the gaseous effluent of the vessel in an off-gas system, before the cooled and cleaned off-gas is released to the atmosphere. Iodine is chemically or physically removed from the off-gas. Otherwise, the only egress materials from the volume reduction system are containerized dry solids and tramp material. The bed material used during each mode may be circulated, cleaned, stored and exchanged from within the bed vessel by use of a bed material handling system. An instrumentation and control system provides operator information, monitors performance characteristics, implements start up and shut down procedures, and initiates alarms and emergency procedures during abnormal conditions

Influence of length of interval between pulses in PDR brachytherapy (PDRBT on value of Biologically Equivalent Dose (BED in healthy tissues

Directory of Open Access Journals (Sweden)

Tomasz Piotrowski

2010-07-01

Full Text Available Purpose: Different PDR treatment schemas are used in clinical practice, however optimal length of interval between pulses still remains unclear. The aim of this work was to compare value of BED doses measured in surrounded healthy tissues according to different intervals between pulses in PDRBT. Influence of doses optimization on BED values was analyzed.Material and methods: Fifty-one patients treated in Greater Poland Cancer Centre were qualified for calculations.Calculations of doses were made in 51 patients with head and neck cancer, brain tumor, breast cancer, sarcoma, penis cancer and rectal cancer. Doses were calculated with the use of PLATO planning system in chosen critical points in surrounded healthy tissues. For all treatment plans the doses were compared using Biologically Equivalent Dose formula.Three interval lengths (1, 2 and 4 hours between pulses were chosen for calculations. For statistical analysis Friedman ANOVA test and Kendall ratio were used.Results: The median value of BED in chosen critical points in healthy tissues was statistically related to the length of interval between PDR pulses and decreased exponentially with 1 hour interval to 4 hours (Kendall = from 0.48 to 1.0; p = from 0.002 to 0.00001.Conclusions: Prolongation of intervals between pulses in PDR brachytherapy was connected with lower values of BED doses in healthy tissues. It seems that longer intervals between pulses reduced the risk of late complications, but also decreased the tumour control. Furthermore, optimization influenced the increase of doses in healthy tissues.

The role of each compartment in a two-compartment vertical flow reactor for ferruginous mine water treatment.

Science.gov (United States)

Yim, G J; Cheong, Y W; Hong, J H; Hur, W

2014-10-01

A vertical flow reactor (VFR) has been suggested for remediation of ferruginous mine drainage that passes down through an accreting bed of ochre. However, a VFR has a limited operation time until the system begins to overflow. In this study, a mathematical model was developed as a part of the effort to explore the operation of a VFR, showing dynamic changes in the head differences, ochre depths, and Fe(II)/Fe(III) concentrations in the effluent flow. The analysis showed that VFR operation time extended from 148.5 days to 163 days in an equally divided and to 168.4 days in asymmetrically (0.72:0.28) divided two-compartment VFR, suggesting that an optimum compartment ratio exists that maximizes the VFR operation time. A constant head filtration in the first compartment maximized filtration efficiency and thus prolonged VFR longevity in the two-compartment VFR. Fe(II) oxidation and ochre formation should be balanced with the permeability of the ochre bed to maximize the VFR operation time and minimize the residual Fe(II) in the effluent. Accelerated Fe(II) oxidation affected the optimum ratio of the compartment area and reduced the residual Fe(II) in the effluent. The VFR operation time can be prolonged significantly from 764 days to 3620 days by increasing the rate of ochre formation, much more than by accelerating the Fe(II) oxidation. During the prolonged VFR operation, ochre formed largely in the first compartment, while overflowing mine water with reduced iron content was effectively filtered in the second compartment. These results not only provide a better understanding of VFR operation but also suggest the direction of evolution of two-compartment VFR toward a compact and highly efficient facility integrated with an aerated cascade and with automatic coagulant feeding. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gender Differences in Isokinetic Strength after 60 and 90 d Bed Rest

Science.gov (United States)

English, K. L.; Ploutz-Snyder, R. J.; Cromwell, R. L.; Ploutz-Snyder, L. L.

2010-01-01

Recent reports suggest that changes in muscle strength following disuse may differ between males and females. PURPOSE: To examine potential gender differences in strength changes following 60 and 90 d of experimental bed rest. METHODS: Isokinetic extensor and flexor strength of the knee (60deg and 180deg/s, concentric only), ankle (30deg/s, concentric and eccentric), and trunk (60deg/s, concentric only) were measured following 60 d (males: n=4, 34.5+/-9.6 y; females: n=4, 35.5+/-8.2 y) and 90 d (males: n=10, 31.4+/-4.8 y; females: n=5, 37.6+/-9.9 y) of 6-degree head-down-tilt bed rest (BR; N=23). Subjects were fed a controlled diet (55%/15%/ 30%, CHO/PRO/FAT) that maintained body weight within 3% of the weight recorded on Day 3 of bed rest. After a familiarization session, testing was conducted 6 d before BR and 2 d after BR completion. Peak torque and total work were calculated for the tests performed. To allow us to combine data from both 60- and 90-d subjects, we used a mixed-model statistical analysis in which time and gender were fixed effects and bed rest duration was a random effect. Log-transformations of strength measures were utilized when necessary in order to meet statistical assumptions. RESULTS: Main effects were seen for both time and gender (p<0.05), showing decreased strength in response to bed rest for both males and females, and males stronger than females for most strength measures. Only one interaction effect was observed: females exhibited a greater loss of trunk extensor peak torque at 60 d versus pre-BR, relative to males (p=0.004). CONCLUSION: Sixty and 90 d of BR induced significant losses in isokinetic muscle strength of the locomotor and postural muscles of the knee, ankle, and trunk. Although males were stronger than females for most of the strength measures that we examined, only changes in trunk extensor peak torque were greater for females than males at day 60 of bed rest

Combined effect of head down tilt (HDT) and gamma radiation on the higher nervous activity of the rats

International Nuclear Information System (INIS)

Shtemberg, A.S.

1992-01-01

The paper deals with a combined effect of 30-day head down tilt (HDT) and gamma-radiation at a dose of 3 Gy on the higher nervous activity of the rats. The 30-day HDT disturbs the process of forming the motor-drinking differentiated conditioned reflex coming to a reduction of internal inhibition, generalization and sluggishness of a stimulation process. Functionally, these processes are reflected by a behavioral pattern shifting to stable stereotype impeding the formation of differentiated inhibition. Against HDT the unidirectional gamma-radiation exposure increases this effects. In some cases, it leads to blocking the adaptational procesess showing in the development of neurotic responses or deep, beyond the limits, inhibition

The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

Energy Technology Data Exchange (ETDEWEB)

Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

2003-11-15

The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

Public knowledge of head and neck cancer.

LENUS (Irish Health Repository)

O'Connor, T E

2010-04-01

Studies show 60% of patients with newly diagnosed Head & Neck Squamous Cell Cancer in Ireland, present with advanced disease. A poor level of knowledge and awareness among the public of Head & Neck Cancer, is an important consideration in the often delayed presentation for medical attention in many of these cases. Our study surveyed 200 members of the public to assess their knowledge and awareness of Head & Neck Cancer. One hundred and forty (70%) of respondents had never encountered the term "Head & Neck Cancer". One hundred and forty six (73%) failed to identify excessive alcohol consumption as a risk factor. Less than 100 (50%) would have concern about persisting hoarseness or a prolonged oral ulcer. An urgent need exists to raise awareness of Head & Neck Cancer among the public in Ireland.

Head flexion angle while using a smartphone.

Science.gov (United States)

Lee, Sojeong; Kang, Hwayeong; Shin, Gwanseob

2015-01-01

Repetitive or prolonged head flexion posture while using a smartphone is known as one of risk factors for pain symptoms in the neck. To quantitatively assess the amount and range of head flexion of smartphone users, head forward flexion angle was measured from 18 participants when they were conducing three common smartphone tasks (text messaging, web browsing, video watching) while sitting and standing in a laboratory setting. It was found that participants maintained head flexion of 33-45° (50th percentile angle) from vertical when using the smartphone. The head flexion angle was significantly larger (p smartphone, could be a main contributing factor to the occurrence of neck pain of heavy smartphone users. Practitioner Summary: In this laboratory study, the severity of head flexion of smartphone users was quantitatively evaluated when conducting text messaging, web browsing and video watching while sitting and standing. Study results indicate that text messaging while sitting caused the largest head flexion than that of other task conditions.

Axis of eye rotation changes with head-pitch orientation during head impulses about earth-vertical.

Science.gov (United States)

Migliaccio, Americo A; Schubert, Michael C; Clendaniel, Richard A; Carey, John P; Della Santina, Charles C; Minor, Lloyd B; Zee, David S

2006-06-01

The goal of this study was to assess how the axis of head rotation, Listing's law, and eye position influence the axis of eye rotation during brief, rapid head rotations. We specifically asked how the axis of eye rotation during the initial angular vestibuloocular reflex (VOR) changed when the pitch orientation of the head relative to Earth-vertical was varied, but the initial position of the eye in the orbit and the orientation of Listing's plane with respect to the head were fixed. We measured three-dimensional eye and head rotation axes in eight normal humans using the search coil technique during head-and-trunk (whole-body) and head-on-trunk (head-only) "impulses" about an Earth-vertical axis. The head was initially oriented at one of five pitch angles (30 degrees nose down, 15 degrees nose down, 0 degrees, 15 degrees nose up, 30 degrees nose up). The fixation target was always aligned with the nasooccipital axis. Whole-body impulses were passive, unpredictable, manual, rotations with peak-amplitude of approximately 20 degrees , peak-velocity of approximately 80 degrees /s, and peak-acceleration of approximately 1000 degrees /s2. Head-only impulses were also passive, unpredictable, manual, rotations with peak-amplitude of approximately 20 degrees , peak-velocity of approximately 150 degrees /s, and peak-acceleration of approximately 3000 degrees /s2. During whole-body impulses, the axis of eye rotation tilted in the same direction, and by an amount proportional (0.51 +/- 0.09), to the starting pitch head orientation (P rotation could be predicted from vectorial summation of the gains (eye velocity/head velocity) obtained for rotations about the pure yaw and roll head axes. Thus, even when the orientation of Listing's plane and eye position in the orbit are fixed, the axis of eye rotation during the VOR reflects a compromise between the requirements of Listing's law and a perfectly compensatory VOR.

Incineration of Sludge in a Fluidized-Bed Combustor

OpenAIRE

Chien-Song Chyang; Yu-Chi Wang

2017-01-01

For sludge disposal, incineration is considered to be better than direct burial because of regulations and space limitations in Taiwan. Additionally, burial after incineration can effectively prolong the lifespan of a landfill. Therefore, it is the most satisfactory method for treating sludge at present. Of the various incineration technologies, the fluidized bed incinerator is a suitable choice due to its fuel flexibility. In this work, sludge generated from industrial plants was treated in ...

Compartment in vertical flow reactor for ferruginous mine water

Science.gov (United States)

Hur, Won; Cheong, Young-Wook; Yim, Gil-Jae; Ji, Sang-Woo; Hong, Ji-Hye

2014-05-01

Mine effluents contain varying concentrations of ferrous ion along with other metal ions. Fe(II) that quickly oxidizes to form precipitates in the presence of oxygen under net alkaline or neutral conditions. Thus, passive treatment methods are designed for the mine water to reside in an open containment area so as to allow simultaneous oxidation and precipitation of Fe(II), such as in a lagoon or an oxidation pond. A vertical flow reactor (VFR) was also suggested to remediate ferruginous mine drainage passing down through an accreting bed of ochre. However, VFR has a limited operation time until the system begins to overflow. It was also demonstrated that two-compartment VFR has a longer operation time than single compartment VFR of same size. In this study, a mathematical model was developed as a part of efforts to explore the operation of VFR, showing dynamic changes in head differences, ochre depth and Fe(II)/Fe(III) concentration in the effluent flow. The analysis shows that Fe(II) oxidation and ochre formation should be balanced with permeability of ochre bed to maximize VFR operation time and minimize residual Fe(II) in the effluent. The model demonstrates that two compartment VFR can have a longer operation time than a single-compartment VFR and that an optimum compartment ratio exists that maximize VFR operation time. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation. Taken together, ochre forms largely in the first compartment while overflowed mine water with reduced iron contents is efficiently filtered in the second compartment. These results provide us a better understanding of VFR operation and optimum design criteria for maximum operation time in a two-compartment VFR. Rapid ochre accretion in the first compartment maintains constant hydraulic

SCDAP/RELAP5 modeling of movement of melted material through porous debris in lower head

International Nuclear Information System (INIS)

Siefken, L. J.; Harvego, E. A.

2000-01-01

A model is described for the movement of melted metallic material through a ceramic porous debris bed. The model is designed for the analysis of severe accidents in LWRs, wherein melted core plate material may slump onto the top of a porous bed of relocated core material supported by the lower head. The permeation of the melted core plate material into the porous debris bed influences the heatup of the debris bed and the heatup of the lower head supporting the debris. A model for mass transport of melted metallic material is applied that includes terms for viscosity and turbulence but neglects inertial and capillary terms because of their small value relative to gravity and viscous terms in the momentum equation. The relative permeability and passability of the porous debris are calculated as functions of debris porosity, particle size, and effective saturation. An iterative numerical solution is used to solve the set of nonlinear equations for mass transport. The effective thermal conductivity of the debris is calculated as a function of porosity, particle size, and saturation. The model integrates the equations for mass transport with a model for the two-dimensional conduction of heat through porous debris. The integrated model has been implemented into the SCDAP/RELAP5 code for the analysis of the integrity of LWR lower heads during severe accidents. The results of the model indicate that melted core plate material may permeate to near the bottom of a 1m deep hot porous debris bed supported by the lower head. The presence of the relocated core plate material was calculated to cause a 12% increase in the heat flux on the external surface of the lower head

Surveillance of Ocular Parameters and Visual Function in Bed Rest Subjects

Science.gov (United States)

Cromwell, Ronita L.

2011-01-01

Recent visual changes in astronauts have raised concern about ocular health during long duration spaceflight. Seven cases have been documented in astronauts who spent 6 months aboard the International Space Station. These astronauts were male ranging in age from 45 to 55 years old. All astronauts exhibited pre- to post flight refractive changes. Decreased intraocular pressure (IOP) post flight was observed in 3 cases. Fundoscopic exams revealed post flight findings of choroidal folds in 4 cases, optic disc edema in 5 cases and the presence of cotton wool spots in 3 cases. Optical coherence tomography (OCT) confirmed findings of choroidal folds and disc edema, and also documented retinal nerve fiber layer thickening (5 cases). Findings from MRI examinations showed posterior globe flattening (5 cases), optic nerve sheath distention (6 cases) and torturous optic nerves (2 cases). Of the 7 cases, intracranial pressure was measured on 4 astronauts. These 4 showed elevated ICP post-flight that remained elevated for as long as 19 months in one case. While the etiology remains unknown, hypotheses speculate that venous insufficiency or hypertension in the brain caused by cephalad fluid shifts during spaceflight are possible mechanisms for ocular changes seen in astronauts. Head-down tilt bed rest is a spaceflight analog that induces cephalad fluid shifts. This study is designed to provide ocular monitoring of bed rest subjects and determine whether clinically relevant changes are found. Ocular Changes

Prolonged bed rest decreases skeletal muscle and whole body protein synthesis

Science.gov (United States)

Ferrando, A. A.; Lane, H. W.; Stuart, C. A.; Davis-Street, J.; Wolfe, R. R.

1996-01-01

We sought to determine the extent to which the loss of lean body mass and nitrogen during inactivity was due to alterations in skeletal muscle protein metabolism. Six male subjects were studied during 7 days of diet stabilization and after 14 days of stimulated microgravity (-6 degrees bed rest). Nitrogen balance became more negative (P protein synthesis (PS; P protein also decreased by 46% (P protein breakdown and inward transport. Whole body protein synthesis determined by [15N]alanine ingestion on six subjects also revealed a 14% decrease (P protein breakdown change significantly. These results indicate that the loss of body protein with inactivity is predominantly due to a decrease in muscle PS and that this decrease is reflected in both whole body and skeletal muscle measures.

ADVANCES IN CLOG STATE MONITORING FOR USE IN AUTOMATED REED BED INSTALLATIONS

Directory of Open Access Journals (Sweden)

Theodore HUGHES-RILEY

2014-06-01

Full Text Available Constructed wetlands are a popular form of waste-water treatment that have proliferated across Europe and the rest of the world in recent years as an environmentally conscious form of waste water treatment. The ability to monitor the conditions in the bed and control input factors such as heating and aeration may extend the lifetime of the reed bed substantially beyond the ten year lifetime normally reached. The Autonomous Reed Bed Installation (ARBI project is an EU FP7 initiative to develop a reed bed with automated control over input parameters based on readings taken from embedded sensors. Automated remedial action may improve bed treatment efficiency, and prolong the life of the bed and avoiding the need to refurbish the bed, which is both time consuming and costly. One critical parameter to observe is the clog state of the reed bed, as this can severely impact on the efficiency of water treatment to the point of the bed becoming non-operable. Magnetic resonance (MR sensors can be a powerful tool in determining clogging levels, and has previously been explored in the literature. This work is based on a conference paper (2nd International Conference "Water resources and wetlands", 2014 and details magnetic sensors suitable for long-term embedding into a constructed wetland. Unlike previous studies this work examines a probe embedded into a wetland.

Influence of body position on cortical pain-related somatosensory processing: an ERP study.

Directory of Open Access Journals (Sweden)

Chiara Spironelli

Full Text Available BACKGROUND: Despite the consistent information available on the physiological changes induced by head down bed rest, a condition which simulates space microgravity, our knowledge on the possible perceptual-cortical alterations is still poor. The present study investigated the effects of 2-h head-down bed rest on subjective and cortical responses elicited by electrical, pain-related somatosensory stimulation. METHODOLOGY/PRINCIPAL FINDINGS: Twenty male subjects were randomly assigned to two groups, head-down bed rest (BR or sitting control condition. Starting from individual electrical thresholds, Somatosensory Evoked Potentials were elicited by electrical stimuli administered randomly to the left wrist and divided into four conditions: control painless condition, electrical pain threshold, 30% above pain threshold, 30% below pain threshold. Subjective pain ratings collected during the EEG session showed significantly reduced pain perception in BR compared to Control group. Statistical analysis on four electrode clusters and sLORETA source analysis revealed, in sitting controls, a P1 component (40-50 ms in the right somatosensory cortex, whereas it was bilateral and differently located in BR group. Controls' N1 (80-90 ms had widespread right hemisphere activation, involving also anterior cingulate, whereas BR group showed primary somatosensory cortex activation. The P2 (190-220 ms was larger in left-central locations of Controls compared with BR group. CONCLUSIONS/SIGNIFICANCE: Head-down bed rest was associated to an overall decrease of pain sensitivity and an altered pain network also outside the primary somatosensory cortex. Results have implications not only for astronauts' health and spaceflight risks, but also for the clinical aspects of pain detection in bedridden patients at risk of fatal undetected complications.

Synthesis and crystal structure of lithium beryllium deuteride Li2BeD4.

Science.gov (United States)

Bulychev, Boris M; Shpanchenko, Roman V; Antipov, Evgeny V; Sheptyakov, Denis V; Bushmeleva, Svetlana N; Balagurov, Anatoly M

2004-10-04

Single-phase ternary deuteride Li(2)BeD(4) was synthesized by a high-pressure high-temperature technique from LiD and BeD(2). The crystal structure of Li(2)BeD(4) was solved from X-ray and neutron powder diffraction data. The compound crystallizes in the monoclinic space group P2(1)/c with lattice parameters a = 7.06228(9) A, b = 8.3378(1) A, c = 8.3465(1) A, beta =93.577(1) degrees, and Z = 8. Its structure contains isolated BeD(4) tetrahedra and Li atoms that are located in the structure interstices. Li(2)BeD(4) does not undergo any structural phase transitions at temperatures down to 8 K.

Static Histomorphometry of the iliac crest after 360 days of antiorthostatic bed rest with and without countermeasures

Science.gov (United States)

Thomsen, J. S.; Morukov, B. V.; Vico, L.; Saparin, P. I.; Gowin, W.

The loss of bone during immobilization is well-known and investigated, whereas the structural changes human cancellous bone undergoes during disuse is less well examined. The aim of the study was to examine the influence of hypokinesia on the static histomorphometric measures of the iliac crest using a 360-day-long bed rest experiment, simulating exposure to microgravity. Eight healthy males underwent 360 days of 5° head-down tilt bed rest. Three subjects were treated with the bisphosphonate Xidifon (900 mg/day) combined with a treadmill and ergonometer exercise regimen (1--2 hours/day) for the entire study period. Five subjects underwent 120 days of bed rest without countermeasures followed by 240 days of bed rest with the treadmill and ergonometer exercise regimen. Transiliac bone biopsies were obtained either at day 0 and 360 or at day 0, 120, and 360 at alternating sides of the ileum. The biopsies were embedded in methylmethacrylate, cut in 7-μm-thick sections, stained with Goldner trichrome, and static histomorphometry was performed. 120 days of bed rest without countermeasures resulted in decreased trabecular bone volume (-6.3%, p = 0.046) and trabecular number (-10.2%, p = 0.080) and increased trabecular separation (14.7%, p = 0.020), whereas 240 days of subsequent bed rest with exercise treatment prevented further significant deterioration of the histomorphometric measures. 360 days of bed rest with bisphosphonate and exercise treatment did not induce any significant changes in any of the histomorphometric measures. The study showed that 120 days of antiorthostatic bed rest without countermeasures induced significant deterioration of iliac crest trabecular bone histomorphometric properties. There are indications that the immobilization induced changes involve a loss of trabeculae rather than a general thinning of the trabeculae. On average, the countermeasures consisting of either bisphosphonate and exercise or exercise alone were able to either prevent

An Estimation of Radiobiological Parameters for Head-and-Neck Cancer Cells and the Clinical Implications

International Nuclear Information System (INIS)

Qi, X. Sharon; Yang, Qiuhui; Lee, Steve P.; Li, X. Allen; Wang, Dian

2012-01-01

In vitro survival measurements using two human head-and-neck cancer (HNC) cell lines were performed. The specially designed split-dose surviving fraction was obtained and fitted to the linear-quadratic formalism. The repair halftime (Tr), the potential doubling time (T d ), α/β and radiosensitivity α, were estimated. Other radiobiological models: EUD, BED, TCP, etc., were used to examine the potential treatment effectiveness of different IMRT techniques. Our data indicated the repair halftime of ~17 min based on two HNC cell lines. The combined α/β, α and T d are α/β = 8.1 ± 4.1 Gy, α = 0.22 ± 0.08 Gy −1 , T d = 4.0 ± 1.8 day, respectively. The prolonged IMRT dose delivery for entire HNC treatment course could possibly result in the loss of biological effectiveness, i.e., the target EUDs decreased by 11% with fraction dose delivery time varying from 5 to 30 min. We determined the sublethal damage repair halftime and other radiobiological parameters for HNC cells, and to evaluate treatment effectiveness of the prolonged dose delivery times associated with different IMRT techniques. The estimated repair halftime for HNC is relatively short and may be comparable to the step-and-shoot IMRT fraction dose delivery time. The effectiveness of IMRT treatment may be improved by reducing the fraction delivery time for HNC treatment

Operational methods of the fluidized bed nuclear reactor

International Nuclear Information System (INIS)

Borges, V.; Sefidvash, F.

1993-01-01

The operational curve of reactivity as a function of porosity of the Fluidized Bed Nuclear Reactor is presented. The strategies for start-up, shut-down and maintaining the reactor critical during operation are described. The inherent safety of the reactor from neutronic point of view under steady state condition is demonstrated. (author)

WISE-2005: Integrative cardiovascular responses with LBNP during 60-day bed rest in women

Science.gov (United States)

Hughson, R. L.; Kerbeci, P.; Arbeille, P.; Mattar, L.; Shoemaker, J. K.

2005-08-01

During 2005, 24 women will take part in the Women International Space-simulation for Exploration (WISE). In this paper we report on the first phase that studied 4 Exercise (EX+LBNP), 4 nutrition (NUT), and 4 no countermeasure control (CON) subjects. The EX+LBNP group completed regular exercise on a treadmill inside LBNP, flywheel resistive exercise and static periods of LBNP, and had recovery days. The NUT group received daily protein supplements. Integrative cardiovascular responses were obtained and here we report data for heart rate during LBNP, blood volume and angiotensin II. LBNP was applied at 0, -10, -20 and -30 mmHg for 2-minutes for each stage. Blood was sampled pre- bed rest and on HDT-60. After 60-days head down bed rest, HR in the CON group increased by 6.1±2.8 bpm at rest and by 20.7±5.0 bpm at -30 mmHg LBNP. The EX+LBNP group had increases of 3.6±5.6 and 11.6±5.4 bpm, while the NUT group HR increased 2.6±3.1 and 9.4±3.6 bpm. The EX+LBNP group had almost no change in blood volume or plasma angiotensin II from pre-bed rest to HDT60, while both the CON and NUT groups had larger increases in plasma volume and almost double concentrations of angiotensin II. These data show a positive effect in the EX+LBNP group on the heart rate response as well as an unexpected possible benefit in the NUT group. Further studies are required to confirm possible cardiovascular benefits of the protein supplement.

A cost sensitive inpatient bed reservation approach to reduce emergency department boarding times.

Science.gov (United States)

Qiu, Shanshan; Chinnam, Ratna Babu; Murat, Alper; Batarse, Bassam; Neemuchwala, Hakimuddin; Jordan, Will

2015-03-01

Emergency departments (ED) in hospitals are experiencing severe crowding and prolonged patient waiting times. A significant contributing factor is boarding delays where admitted patients are held in ED (occupying critical resources) until an inpatient bed is identified and readied in the admit wards. Recent research has suggested that if the hospital admissions of ED patients can be predicted during triage or soon after, then bed requests and preparations can be triggered early on to reduce patient boarding time. We propose a cost sensitive bed reservation policy that recommends optimal bed reservation times for patients. The policy relies on a classifier that estimates the probability that the ED patient will be admitted using the patient information collected and readily available at triage or right after. The policy is cost sensitive in that it accounts for costs associated with patient admission prediction misclassification as well as costs associated with incorrectly selecting the reservation time. Results from testing the proposed bed reservation policy using data from a VA Medical Center are very promising and suggest significant cost saving opportunities and reduced patient boarding times.

Microstructure and Mechanical Properties of Heat-Treated B319 Alloy Diesel Cylinder Heads

Science.gov (United States)

Chaudhury, S. K.; Apelian, D.; Meyer, P.; Massinon, D.; Morichon, J.

2015-07-01

Microstructure and mechanical properties of B319 alloy diesel cylinder heads were investigated in this study. Cylinder heads were heat treated to T5, T6, and T7 tempers using fluidized bed technology. Three different fluidized beds were used, each to solutionize, quench, and age the castings. For comparative purposes, castings were also aged using conventional forced-air circulation electric-resistance furnace. Effects of processing parameters such as temperature, time, and heating rate on microstructural evolution and mechanical properties namely tensile properties and hardness of B319 alloy castings were studied. The number density and size range of precipitates were measured. Results show that the T5 temper has no effect on eutectic phases such as Si- and Fe-rich intermetallic, and Al2Cu. On contrary, both T6 and T7 tempers result in spherodization of the eutectic Si and partial dissolution of the Al2Cu phase. Prolonged solution heat treatment for 8 hours in fluidized bed results in limited dissolution of the secondary eutectic Al2Cu phase. Aging (T6, T7, and T5) results in precipitation of Al5Cu2Mg8Si6 and Al2Cu phases in B319 alloy. The number density of precipitates in T6 temper is greater than in T7 and T5 tempers. The number density of precipitates is also affected by the duration of solution heat treatment. In general, long solution heat treatment (8 hours) results in greater precipitate density than short solution treatment (2 hours). The distribution of precipitates is inhomogeneous and varied across the dendritic structure. In general, precipitation rate of Al5Cu2Mg8Si6 phase is greater near the periphery of the dendrite as compared to the center. This is because Al5Cu2Mg8Si6 nucleates on Si particle, grain boundaries, and triple junction between recrystallized Al grains and Si particles. Similarly, heterogeneous sites such as grain boundaries and Al/Si interface also act as nucleating sites for the precipitation of Al2Cu phase. In general, the

Features of History, Anthropometric Data and Individual Functions of the Liver in Children with Prolonged Jaundice

Directory of Open Access Journals (Sweden)

O.V. Tyajka

2016-11-01

Full Text Available Background. Neonatal jaundice is one of the urgent problems in neonatology. There is a tendency to increase the incidence of prolonged jaundice. The aim of our study was to explore the features of history, anthropometric data and some liver functions in children with prolonged jaundice. Materials and methods. The study involved 111 children with prolonged jaundice aged from 3 weeks to 3 months. In all children with prolonged jaundice, we have examined complete blood count, urinalysis, blood chemistry (determination of total bilirubin and fractions, total protein, albumin, glucose and used instrumental methods of examination — ultrasound of the abdominal cavity and cranial ultrasonography, electrocardiography. Most children with prolonged jaundice were breastfed and were term infants. Results. Indicators of physical development at birth (body weight, body length, head circumference, chest circumference in children with prolonged jaundice and in healthy children had not statistically significant differences. Neonatal jaundice was prolonged in children, who were born from the first pregnancy, — 60 children (54.1 %. A high level of total and indirect bilirubin was accompanied by a low level of albumin in the blood serum of children with prolonged jaundice. Protein-synthesis function of the liver was reduced in children with prolonged jaundice.

Channel change and bed-material transport in the Umpqua River basin, Oregon

Science.gov (United States)

Wallick, J. Rose; O'Connor, Jim E.; Anderson, Scott; Keith, Mackenzie K.; Cannon, Charles; Risley, John C.

2011-01-01

The Umpqua River drains 12,103 square kilometers of western Oregon; with headwaters in the Cascade Range, the river flows through portions of the Klamath Mountains and Oregon Coast Range before entering the Pacific Ocean. Above the head of tide, the Umpqua River, along with its major tributaries, the North and South Umpqua Rivers, flows on a mixed bedrock and alluvium bed, alternating between bedrock rapids and intermittent, shallow gravel bars composed of gravel to cobble-sized clasts. These bars have been a source of commercial aggregate since the mid-twentieth century. Below the head of tide, the Umpqua River contains large bars composed of mud and sand. Motivated by ongoing permitting and aquatic habitat concerns related to in-stream gravel mining on the fluvial reaches, this study evaluated spatial and temporal trends in channel change and bed-material transport for 350 kilometers of river channel along the Umpqua, North Umpqua, and South Umpqua Rivers. The assessment produced (1) detailed mapping of the active channel, using aerial photographs and repeat surveys, and (2) a quantitative estimation of bed-material flux that drew upon detailed measurements of particle size and lithology, equations of transport capacity, and a sediment yield analysis. Bed-material transport capacity estimates at 45 sites throughout the South Umpqua and main stem Umpqua Rivers for the period 1951-2008 result in wide-ranging transport capacity estimates, reflecting the difficulty of applying equations of bed-material transport to a supply-limited river. Median transport capacity values calculated from surface-based equations of bedload transport for each of the study reaches provide indications of maximum possible transport rates and range from 8,000 to 27,000 metric tons per year (tons/yr) for the South Umpqua River and 20,000 to 82,000 metric tons/yr for the main stem Umpqua River upstream of the head of tide; the North Umpqua River probably contributes little bed material. A

Aerobic exercise deconditioning and countermeasures during bed rest.

Science.gov (United States)

Lee, Stuart M C; Moore, Alan D; Everett, Meghan E; Stenger, Michael B; Platts, Steven H

2010-01-01

Bed rest is a well-accepted model for spaceflight in which the physiologic adaptations, particularly in the cardiovascular system, are studied and potential countermeasures can be tested. Bed rest without countermeasures results in reduced aerobic capacity and altered submaximal exercise responses. Aerobic endurance and factors which may impact prolonged exercise, however, have not been well studied. The initial loss of aerobic capacity is rapid, occurring in parallel with the loss of plasma volume. Thereafter, the reduction in maximal aerobic capacity proceeds more slowly and is influenced by central and peripheral adaptation. Exercise capacity can be maintained during bed rest and may be improved during recovery with appropriate countermeasures. Plasma volume restoration, resistive exercise, orthostatic stress, aerobic exercise, and aerobic exercise plus orthostatic stress all have been tested with varying levels of success. However, the optimal combination of elements-exercise modality, intensity, duration, muscle groups exercised and frequency of aerobic exercise, orthostatic stress, and supplementary resistive or anaerobic exercise training-has not been systematically evaluated. Currently, frequent (at least 3 days per week) bouts of intense exercise (interval-style and near maximal) with orthostatic stress appears to be the most efficacious method to protect aerobic capacity during bed rest. Further refinement of protocols and countermeasure hardware may be necessary to insure the success of countermeasures in the unique environment of space.

Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

Science.gov (United States)

Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

1998-02-20

A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before. Copyright 1998 John Wiley & Sons, Inc.

Association of acute adverse effects with high local SAR induced in the brain from prolonged RF head and neck hyperthermia

International Nuclear Information System (INIS)

Adibzadeh, F; Verhaart, R F; Rijnen, Z; Franckena, M; Van Rhoon, G C; Paulides, M M; Verduijn, G M; Fortunati, V

2015-01-01

To provide an adequate level of protection for humans from exposure to radio-frequency (RF) electromagnetic fields (EMF) and to assure that any adverse health effects are avoided. The basic restrictions in terms of the specific energy absorption rate (SAR) were prescribed by IEEE and ICNIRP. An example of a therapeutic application of non-ionizing EMF is hyperthermia (HT), in which intense RF energy is focused at a target region. Deep HT in the head and neck (H and N) region involves inducing energy at 434 MHz for 60 min on target. Still, stray exposure of the brain is considerable, but to date only very limited side-effects were observed. The objective of this study is to investigate the stringency of the current basic restrictions by relating the induced EM dose in the brain of patients treated with deep head and neck (H and N) HT to the scored acute health effects. We performed a simulation study to calculate the induced peak 10 g spatial-averaged SAR (psSAR 10g ) in the brains of 16 selected H and N patients who received the highest SAR exposure in the brain, i.e. who had the minimum brain-target distance and received high forwarded power during treatment. The results show that the maximum induced SAR in the brain of the patients can exceed the current basic restrictions (IEEE and ICNIRP) on psSAR 10g for occupational environments by 14 times. Even considering the high local SAR in the brain, evaluation of acute effects by the common toxicity criteria (CTC) scores revealed no indication of a serious acute neurological effect. In addition, this study provides pioneering quantitative human data on the association between maximum brain SAR level and acute adverse effects when brains are exposed to prolonged RF EMF. (paper)

Caloric restriction decreases orthostatic tolerance independently from 6° head-down bedrest.

Directory of Open Access Journals (Sweden)

John P Florian

Full Text Available Astronauts consume fewer calories during spaceflight and return to earth with an increased risk of orthostatic intolerance. Whether a caloric deficiency modifies orthostatic responses is not understood. Thus, we determined the effects of a hypocaloric diet (25% caloric restriction during 6° head down bedrest (an analog of spaceflight on autonomic neural control during lower body negative pressure (LBNP. Nine healthy young men completed a randomized crossover bedrest study, consisting of four (2 weeks each interventions (normocaloric bedrest, normocaloric ambulatory, hypocaloric bedrest, hypocaloric ambulatory, each separated by 5 months. Muscle sympathetic nerve activity (MSNA was recorded at baseline following normocaloric and hypocaloric interventions. Heart rate (HR and arterial pressure were recorded before, during, and after 3 consecutive stages (7 min each of LBNP (-15, -30, -45 mmHg. Caloric and posture effects during LBNP were compared using two-way ANOVA with repeated measures. There was a strong trend toward reduced basal MSNA following caloric restriction alone (normcaloric vs. hypocaloric: 22±3 vs. 14±4 burst/min, p = 0.06. Compared to the normocaloric ambulatory, both bedrest and caloric restriction were associated with lower systolic blood pressure during LBNP (p<0.01; however, HR responses were directionally opposite (i.e., increase with bedrest, decrease with caloric restriction. Survival analysis revealed a significant reduction in orthostatic tolerance following caloric restriction (normocaloric finishers: 12/16; hypocaloric finishers: 6/16; χ2, p = 0.03. Caloric restriction modifies autonomic responses to LBNP, which may decrease orthostatic tolerance after spaceflight.

Pulmonary complication associated with head and neck cancer surgery

International Nuclear Information System (INIS)

Manzoor, T.; Ahmed, Z.; Sheikh, N.A.; Khan, M.M.

2007-01-01

To evaluate the frequency of short-term pulmonary complications in the patients undergoing various head and neck cancer surgeries in our setup and to assess possible risk factors responsible for these complications. Seventy patients of age group 20 to 80 years, regardless of gender, treated surgically for head and neck cancers were enrolled. Main outcome measures included development of pulmonary complications following 15 days of oncological surgery. The complications studied were pneumothorax, bronchopneumonia, atelectasis, pulmonary embolism and cardiopulmonary arrest. A total of 24.28% patients suffered from postoperative pulmonary complications; 17.14% developed bronchopneumonia, 5.71% pulmonary embolism, and 1.42% went into cardiopulmonary arrest, none developed pneumothorax or pulmonary atelectasis. A significant correlation of postoperative bronchopneumonia was seen with heavy smoking and assisted ventilation. Pulmonary embolism was associated with extended assisted ventilation and prolonged surgery. Cardiopulmonary arrest was associated with comorbidity and assisted ventilation after surgery. The frequency of bronchopneumonia supersedes all of the postoperative pulmonary complications in head and neck oncological surgery. Patients at risk of developing postoperative complications are heavy smokers, diabetics, those undergoing prolonged surgery, tracheostomy, and extended assisted ventilation. (author)

Gender-related Changes in Dorsal Hand and Foot Vein Function Following 60 Days of Head Down Bed Rest

Science.gov (United States)

Westby, Christian M.; Phillips, Tiffany; Stenger, Michael B.; Platts, Steven H.

2009-01-01

It is well known that female astronauts are more likely to experience post-flight orthostatic hypotension and presyncope compared to male astronauts. It has been suggested that the disproportionally higher incidence of presyncope (83% of female vs. 20% male crewmembers) may be due to sex-related differences in vascular function between the upper and lower limbs. However, much of this evidence is specific to changes in resistance vessels. Given that more than 70% of the circulating blood volume resides in compliance vessels, it is conceivable that even small changes in venous function may contribute to post-flight orthostatic hypotension. In spite of this, little is currently known regarding the influence of microgravity exposure on venous function between males and females. PURPOSE: To determine the influence of 60 days of HDBR on dorsal foot and hand vein function between healthy males (M) and females (F). METHODS: Using 2-D ultrasound, dorsal hand and foot vein diameter responses to intravenous infusions phenylephrine (PE), acetylcholine (ACh), and nitroglycerine (NTG) were determined in 26 adults; 10 females (age:37 +/- 2 yr ) and 16 males (age:34 +/- 2 yr ). Changes in venous function were calculated as the difference between diameter at baseline and following each venoactive drug. Differences in venous function between limb and sexes across HDBR were determined using mixed-effects linear regression. RESULTS: In response to 60 days of HDBR, the change in venousconstrictor response to PE in the dorsal hand veins was not significantly different between M and F. Interestingly, the change in constrictor response in the dorsal foot veins (compared to pre HDBR) was approximately 30% greater in the F, whereas the constrictor response was approximately 45% less in the M (p=0.026). HDBR had no influence on the change in dilator response to ACh, or NTG between M and F and between vascular beds. CONCLUSION: These results demonstrate that 60 days of HDBR contributes to sex

Cardiac atrophy after bed rest and spaceflight

Science.gov (United States)

Perhonen, M. A.; Franco, F.; Lane, L. D.; Buckey, J. C.; Blomqvist, C. G.; Zerwekh, J. E.; Peshock, R. M.; Weatherall, P. T.; Levine, B. D.

2001-01-01

Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity

Use of an Android application "clinometer" for measurement of head down tilt given during subarachnoid block.

Science.gov (United States)

Dixit, R B; Neema, M M

2016-01-01

Head down tilt is given to patients after sub arachnoid block for adjustment of height of block. However, the amount of tilt given is subjective and cannot be documented. We used an android application named "clinometer" to measure exact degree of tilt given by anesthesiologists as their routine practice. This observational study, at a medical college hospital, was done in 130 patients given sub arachnoid block for lower abdominal surgeries. We observed and documented vital data of patients and measured tilt given by application "clinometer." We observed that the application was easy to use and measured tilt each time. The result obtained can be documented, digitally saved and transferred. In 130 patients studied, we observed incidence of degree of tilt as follows: 6-8° tilt in 38 patients (29.23%), 8-10 in 36 patients (27.69%), 10-12 in 30 patients (23.08%), 12-14 in 12 patients (9.23%) and 14-16° tilt in 14 patients (10.77%). Use of application was received with enthusiasm by practicing anesthesiologists. Various possible uses of this application are discussed.

Prolonged oxidative stress down-regulates Early B cell factor 1 with inhibition of its tumor suppressive function against cholangiocarcinoma genesis

Directory of Open Access Journals (Sweden)

Napat Armartmuntree

2018-04-01

Full Text Available Early B cell factor 1 (EBF1 is a transcription factor involved in the differentiation of several stem cell lineages and it is a negative regulator of estrogen receptors. EBF1 is down-regulated in many tumors, and is believed to play suppressive roles in cancer promotion and progression. However, the functional roles of EBF1 in carcinogenesis are unclear. Liver fluke-infection-associated cholangiocarcinoma (CCA is an oxidative stress-driven cancer of bile duct epithelium. In this study, we investigated EBF1 expression in tissues from CCA patients, CCA cell lines (KKU-213, KKU-214 and KKU-156, cholangiocyte (MMNK1 and its oxidative stress-resistant (ox-MMNK1-L cell lines. The formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG was used as an oxidative stress marker. Our results revealed that EBF1 expression was suppressed in cancer cells compared with the individual normal bile duct cells at tumor adjacent areas of CCA tissues. CCA patients with low EBF1 expression and high formation of 8-oxodG were shown to correlate with poor survival. Moreover, EBF1 was suppressed in the oxidative stress-resistant cell line and all of CCA cell lines compared to the cholangiocyte cell line. This suggests that prolonged oxidative stress suppressed EBF1 expression and the reduced EBF1 level may facilitate CCA genesis. To elucidate the significance of EBF1 suppression in CCA genesis, EBF1 expression of the MMNK1 cell line was down-regulated by siRNA technique, and its effects on stem cell properties (CD133 and Oct3/4 expressions, tumorigenic properties (cell proliferation, wound healing and cell migration, estrogen responsive gene (TFF1, estrogen-stimulated wound healing, and cell migration were examined. The results showed that CD133, Oct3/4 and TFF1 expression levels, wound healing, and cell migration of EBF1 knockdown-MMNK1 cells were significantly increased. Also, cell migration of EBF1-knockdown cells was significantly enhanced after 17�

Decreased distensibility of a passive vascular bed in diabetes mellitus

DEFF Research Database (Denmark)

Faris, I; Agerskov, K; Henrikson, O

1982-01-01

exercise and (b) in a vascular bed locally paralysed by the injection of papaverine. Five normal subjects, six patients with long-standing Type 1 diabetes and six non-diabetic patients with severe atherosclerosis affecting the legs were studied. Blood flow was measured in the anterior tibial muscle......This study was undertaken to determine whether the distensibility of a passive vascular bed is reduced in Type 1 (insulin-dependent) diabetic patients with microangiopathy. The change in blood flow induced by 45 degrees head-up tilting was studied in two systems: (a) following maximal ischaemic...... by the isotope washout technique. The median increase in blood flow produced by tilting was greater in normal subjects than in diabetic subjects in both the locally-relaxed bed (58% and 14% respectively) and after maximal ischaemic exercise (45% and 4% respectively). In the atherosclerotic subjects, the increase...

Effects of turning on skin-bed interface pressures in healthy adults.

Science.gov (United States)

Peterson, Matthew J; Schwab, Wilhelm; van Oostrom, Johannes H; Gravenstein, Nikolaus; Caruso, Lawrence J

2010-07-01

This paper is a report of a study of the effects of lateral turning on skin-bed interface pressures in the sacral, trochanteric and buttock regions, and its effectiveness in unloading at-risk tissue. Minimizing skin-support surface interface pressure is important in pressure ulcer prevention, but the effect of standard patient repositioning on skin interface pressure has not been objectively established. Data were collected from 15 healthy adults from a university-affiliated hospital. Mapped 24-inch x 24-inch (2304 half-inch sensors) interface pressure profiles were obtained in the supine position, followed by lateral turning with pillow or wedge support and subsequent head-of-bed elevation to 30 degrees . Raising the head-of-bed to 30 degrees in the lateral position statistically significantly increased peak interface pressures and total area > or = 32 mmHg. Comparing areas > or = 32 mmHg from all positions, 93% of participants had skin areas with interface pressures > or = 32 mmHg throughout all positions (60 +/- 54 cm(2)), termed 'triple jeopardy areas'. The triple jeopardy area increased statistically significantly with wedges as compared to pillows (153 +/- 99 cm(2) vs. 48 +/- 47 cm(2), P turning by experienced intensive care unit nurses does not reliably unload all areas of high skin-bed interface pressures. These areas remain at risk for skin breakdown, and help to explain why pressure ulcers occur despite the implementation of standard preventive measures. Support materials for maintaining lateral turned positions can also influence tissue unloading and triple jeopardy areas.

An Intelligent FPGA Based Anti-Sweating System for Bed Sore Prevention in a Clinical Environment

Directory of Open Access Journals (Sweden)

K. S. Jaichandar

2011-01-01

Full Text Available Bed sores, a common problem among immobile patients occur as a result of continuous sweating due to increase in skin to bed surface temperature in patients lying on same posture for prolonged period. If left untreated, the skin can break open and become infected. Currently adopted methods for bed sores prevention include: use of two hourly flip chat for repositioning patient or use of air fluidized beds. However, the setbacks of these preventive measures include either use of costly equipment or wastage of human resources. This paper introduces an intelligent low cost FPGA based anti-sweating system for bed sores prevention in a clinical environment. The developed system consists of bed surface implanted temperature sensors interfaced with an FPGA chip for sensing the temperature change in patient’s skin to bed surface. Based on the temperature change, the FPGA chip select the - mode (heater/cooler and speed of the fan module. Furthermore, an alarm module was implemented to alert the nurse to reposition the patient only if patient’s skin to bed surface temperature exceeds a predefined threshold thereby saving human resources. By integrating the whole system into a single FPGA chip, we were able to build a low cost compact system without sacrificing processing power and flexibility.

Replacement of daily load attenuates but does not prevent changes to the musculoskeletal system during bed rest

Directory of Open Access Journals (Sweden)

Peter R. Cavanagh, PhD DSc

2016-12-01

Full Text Available The dose-response effects of exercise in reduced gravity on musculoskeletal health have not been well documented. It is not known whether or not individualized exercise prescriptions can be effective in preventing the substantial loss in bone mineral density and muscle function that have been observed in space flight and in bed rest. In this study, typical daily loads to the lower extremities were quantified in free-living subjects who were then randomly assigned to control or exercise groups. Subjects were confined to 6-degree head-down bed rest for 84 days. The exercise group performed individually prescribed 1 g loaded locomotor exercise to replace their free-living daily load. Eleven subjects (5 exercise, 6 control completed the protocol. Volumetric bone mineral density results from quantitative computed tomography demonstrated that control subjects lost significant amounts of bone in the intertrochanteric and total hip regions (p  0.0125. Pre-and post-bed rest muscle volumes were calculated from analysis of magnetic resonance imaging data. The exercise group retained a larger percentage of their total quadriceps and gastrocnemius muscle volume (−7.2% ± 5.9, −13.8% ± 6.1, respectively than their control counterparts (−23.3% ± 5.9, −33.0 ± 8.2, respectively; p  0.05. The decline in VO2max was 17% ± 18 in exercising subjects (p  0.05. In summary, the decline in a number of important measures of musculoskeletal and cardiovascular health was attenuated but not eliminated by a subject-specific program of locomotor exercise designed to replace daily load accumulated during free living. We conclude that single daily bouts of exposure to locomotor exercise can play a role in a countermeasures program during bed rest, and perhaps space flight, but are not sufficient in their own right to ensure musculoskeletal or cardiovascular health. Keywords: Space flight, Bed rest, Exercise, Biomechanics, Simulation, Gravity

A eukaryotic-acquired gene by a biotrophic phytopathogen allows prolonged survival on the host by counteracting the shut-down of plant photosynthesis.

Science.gov (United States)

Garavaglia, Betiana S; Thomas, Ludivine; Gottig, Natalia; Dunger, Germán; Garofalo, Cecilia G; Daurelio, Lucas D; Ndimba, Bongani; Orellano, Elena G; Gehring, Chris; Ottado, Jorgelina

2010-01-28

Xanthomonas citri pv. citri, the bacteria responsible for citrus canker posses a biological active plant natriuretic peptide (PNP)-like protein, not present in any other bacteria. PNPs are a class of extracellular, systemically mobile peptides that elicit a number of plant responses important in homeostasis and growth. Previously, we showed that a Xanthomonas citri pv. citri mutant lacking the PNP-like protein XacPNP produced more necrotic lesions in citrus leaves than wild type infections and suggested a role for XacPNP in the regulation of host homeostasis. Here we have analyzed the proteome modifications observed in citrus leaves infected with the wild type and XacPNP deletion mutant bacteria. While both of them cause down-regulation of enzymes related to photosynthesis as well as chloroplastic ribosomal proteins, proteins related to defense responses are up-regulated. However, leaves infiltrated with the XacPNP deletion mutant show a more pronounced decrease in photosynthetic proteins while no reduction in defense related proteins as compared to the wild-type pathogen. This suggests that XacPNP serves the pathogen to maintain host photosynthetic efficiency during pathogenesis. The results from the proteomics analyses are consistent with our chlorophyll fluorescence data and transcript analyses of defense genes that show a more marked reduction in photosynthesis in the mutant but no difference in the induction of genes diagnostic for biotic-stress responses. We therefore conclude that XacPNP counteracts the shut-down of host photosynthesis during infection and in that way maintains the tissue in better conditions, suggesting that the pathogen has adapted a host gene to modify its natural host and render it a better reservoir for prolonged bacterial survival and thus for further colonization.

Household bed net ownership and use among under-5 children in Nigeria

Directory of Open Access Journals (Sweden)

Osuorah DC

2013-07-01

sleeping under a bed net (r = 0.706, P < 0.001. Acquisition of these bed nets at no cost significantly determined ownership (P < 0.001 but not usage (P = 0.450. Ownership of a bed net was significantly higher in households in rural areas (P = 0.001, poorer households (P = 0.001, households with an under-5 child (P = 0.001, households whose heads were male (P = 0.001, and of lower educational attainment (P = 0.010. There was a greater likelihood of under-5 children sleeping under a bed net in households with two or more under-5 children (odds ratio [OR] 1.26; CI: 1.05-1.66, two or more bed nets (OR 2.03; CI: 1.56-2.66, and in households whose heads were younger ([OR 2.79; CI: 1.65–4.70] for household heads younger than 29 years and [OR 1.6; CI: 1.17–2.19] for those 30-49 years of age, female (OR 1.61; CI: 1.00-2.61, and poorer (OR 1.77; CI: 1.03-3.04, and less likely in households with more than three other (aside from the under-5 children household members ([OR 0.23; CI: 0.08-0.69] for household with 4–6 family members and [OR 0.20; CI: 0.07–0.61] for households with 7 or more family members. Malaria parasitemia in under-5 children was higher in: households without a bed net (41.9% versus [vs] 34.2% (P = 0.016, in children who did not sleep under a bed net (39.7% vs 35.0% (P = 0.292, in poor households compared to middle and rich households (50.5% vs 44.9% vs 25.9%; P = 0.001, and households in rural settlements (42.6% vs 19.6% (P = 0.001.Conclusion: Bed net ownership in households in Nigeria is poor and does not translate to usage. Governments and organizations should not just distribute these nets free of charge to households, but also follow up with regular visits and provision of household education to ensure consistent and correct use, especially amongst under-5 children and pregnant women, who are the most vulnerable to infections and complications from malaria.Keywords: household, bed nets, under-5 children, Nigeria

System for the Reduction of Substances in Reject Water from Reed-Bed Sludge Mineralization Plants

DEFF Research Database (Denmark)

2004-01-01

The invention is a system for the reduction of substances in reject water from reed-bed sludge mineralization plants (also referred to as sludge dewatering reed-beds). The systems utilizes the composition of substances in reject water from reed-beds and that of sludge to reduce substance mass from...... the reject water via recirculation into a mixed reactor and back onto the reed-beds. The mixed rector consists of a container in which sludge (that is typically loaded directly on to reed-beds) is mixed with recirculated reject water from reed-beds. The sludge mixture has a definable hydraulic retention time...... of by sending it back to the head of a wastewater treatment plant. The system has proven to reduce the mass of nitrogen, COD, and water in the reject water, and can possibly reduce phosphorus and other substances. The overall effect is a reduction in the substance recycle within a wastewater treatment plant...

A novel active heads-up display for driver assistance.

Science.gov (United States)

Doshi, Anup; Cheng, Shinko Yuanhsien; Trivedi, Mohan Manubhai

2009-02-01

In this paper, we introduce a novel laser-based wide-area heads-up windshield display which is capable of actively interfacing with a human as part of a driver assistance system. The dynamic active display (DAD) is a unique prototype interface that presents safety-critical visual icons to the driver in a manner that minimizes the deviation of his or her gaze direction without adding to unnecessary visual clutter. As part of an automotive safety system, the DAD presents alerts in the field of view of the driver only if necessary, which is based upon the state and pose of the driver, vehicle, and environment. This paper examines the effectiveness of DAD through a comprehensive comparative experimental evaluation of a speed compliance driver assistance system, which is implemented on a vehicular test bed. Three different types of display protocols for assisting a driver to comply with speed limits are tested on actual roadways, and these are compared with a conventional dashboard display. Given the inclination, drivers who are given an overspeed warning alert reduced the time required to slow down to the speed limit by 38% (p system.

Fluidized bed reactor for working up carbon coated particles

International Nuclear Information System (INIS)

Marschollek, M.; Simon, W.; Walter, C.

1981-01-01

A fluidized bed reactor is described for working up carbon coated particles, particularly nuclear fuel particles or fertile material particles consisting essentially of a cylindrical portion connected to a conical portion. Gas supply pipes, gas distribution space and gas distribution heads are provided within the conical reactor lower portion, the gas distribution members being arranged in at least two superimposed planes and distributed symmetrically over the cross-section of the reactor

A eukaryotic-acquired gene by a biotrophic phytopathogen allows prolonged survival on the host by counteracting the shut-down of plant photosynthesis.

Directory of Open Access Journals (Sweden)

Betiana S Garavaglia

Full Text Available Xanthomonas citri pv. citri, the bacteria responsible for citrus canker posses a biological active plant natriuretic peptide (PNP-like protein, not present in any other bacteria. PNPs are a class of extracellular, systemically mobile peptides that elicit a number of plant responses important in homeostasis and growth. Previously, we showed that a Xanthomonas citri pv. citri mutant lacking the PNP-like protein XacPNP produced more necrotic lesions in citrus leaves than wild type infections and suggested a role for XacPNP in the regulation of host homeostasis. Here we have analyzed the proteome modifications observed in citrus leaves infected with the wild type and XacPNP deletion mutant bacteria. While both of them cause down-regulation of enzymes related to photosynthesis as well as chloroplastic ribosomal proteins, proteins related to defense responses are up-regulated. However, leaves infiltrated with the XacPNP deletion mutant show a more pronounced decrease in photosynthetic proteins while no reduction in defense related proteins as compared to the wild-type pathogen. This suggests that XacPNP serves the pathogen to maintain host photosynthetic efficiency during pathogenesis. The results from the proteomics analyses are consistent with our chlorophyll fluorescence data and transcript analyses of defense genes that show a more marked reduction in photosynthesis in the mutant but no difference in the induction of genes diagnostic for biotic-stress responses. We therefore conclude that XacPNP counteracts the shut-down of host photosynthesis during infection and in that way maintains the tissue in better conditions, suggesting that the pathogen has adapted a host gene to modify its natural host and render it a better reservoir for prolonged bacterial survival and thus for further colonization.

Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

Directory of Open Access Journals (Sweden)

W. Kurtz

2013-10-01

Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high

Cutting Edge Localisation in an Edge Profile Milling Head

NARCIS (Netherlands)

Fernandez Robles, Laura; Azzopardi, George; Alegre, Enrique; Petkov, Nicolai

2015-01-01

Wear evaluation of cutting tools is a key issue for prolonging their lifetime and ensuring high quality of products. In this paper, we present a method for the effective localisation of cutting edges of inserts in digital images of an edge profile milling head. We introduce a new image data set of

Numerical Modeling of Scour at the Head of a Vertical-Wall Breakwater in Waves

Science.gov (United States)

Baykal, C.; Balcı, H. B.; Sumer, B. M.; Fuhrman, D. R.

2017-12-01

This study presents a 3D numerical modeling study on the flow and scour at the head of a vertical-wall breakwater in regular waves. The numerical model utilized in the study is based on that given by Jacobsen (2011). The present model has been applied successfully to the scour and backfilling beneath submarine pipelines by Fuhrman et al. (2014), and around a vertical cylindrical pile mounted on a horizontal plane sediment bed by Baykal et al. (2015, 2017). The model is composed of two main modules. The first module is the hydrodynamic model where Reynolds Averaged Navier Stokes (RANS) equations are solved with a k-ω turbulence closure. The second module is the morphologic model which comprises five sub-modules, namely; bed load, suspended load, sand slide, bed evolution and 3D mesh motion. The model is constructed in open-source CFD toolbox OpenFOAM. In this study, the model is applied to experimental data sets of Sumer and Fredsoe (1997) on the scour around a vertical-wall breakwater with a circular round head. Here, it is given the preliminary results of bed evolution of Test-8 of Sumer and Fredsoe (1997) in which a vertical-wall breakwater head with a width of B=140 mm is subjected to oscillatory flow with Tw=2.0 s and maximum orbital velocity at the bed Um=22cm/s, resulting in a Keulegan-Carpenter number, KC=3.14, close to KC experienced in real-life situations (KC = O(1)). The grain size is d=0.17 mm. The Shields parameter in the test case is given as θc=0.11, larger than the critical value for the initiation of motion implying that the scour is in the live-bed regime. The computational domain used in the simulations has the following dimensions: Length, l=40B, Width, w=20B, and Height, h=2B. The total number of cells is O(105) in the simulations. The scoured bed profile computed at the end of 3 periods of oscillatory flow of Test-8 is given in the figure below. The color scale in the figure is given for the ratio of bed elevation to the width of breakwater

Rapid-cycle testing cuts bed turnaround by 85%.

Science.gov (United States)

2004-11-01

You can use rapid-cycle testing to try out new approaches to overcrowding much more frequently than with more traditional process improvement strategies. Improving bed turnaround notification can yield dramatic improvements. Telling staff they have to try a new process only for three days makes it easier to gain buy-in. Look for old policies that are no longer needed, yet continue to keep your staff bogged down.

Evaluation of potentially significant increase of lead in the blood during long-term bed rest and space flight.

Science.gov (United States)

Kondrashov, Vladislav; Rothenberg, Stephen J; Chettle, David; Zerwekh, Joseph

2005-02-01

We address a gap in the knowledge of lead turnover under conditions of prolonged bed rest and microgravity by developing a quantitative model of the amount of lead returned to blood circulation from bone. We offer the hypothesis that skeletal unloading, such as typically occurs during extended bed rest or microgravity, will result in bone lead being released to the blood, as has already been demonstrated in the case of calcium. We use initial bone lead concentrations to develop predictive models of blood lead elevation. Our theoretical calculations with typical bone lead loads measured in today's 40-60-year-old generation, suggest that the estimated blood lead concentrations in long duration (e.g., 100 days) space flight could average between 20 and 40 microg dl(-1), a range with well-established toxic effects. For a similar duration of bed rest, estimated blood lead concentration could be as high as 10-20 microg dl(-1), which is a level of concern, particularly if we consider females of childbearing age. The preliminary experimental results were obtained under multi-institutional collaborations, with the main outcome received from an on-going bed rest study, Prevention of Microgravity-Induced Stone Risk by KMgCitrate, conducted at the General Clinical Research Center (GCRC) of the University of Texas Southwestern Medical Center, Dallas. Based on theoretical modeling and some preliminary experimental results, this concept may have important clinical implications by allowing prediction of the magnitude of blood lead elevation, thereby establishing the means to prevent lead toxicity during long duration space flight of astronauts and in conditions of prolonged bed rest such as complicated pregnancy, spinal cord injury induced paralysis and comatose patients.

Down syndrome and ionizing radiation.

Science.gov (United States)

Verger, P

1997-12-01

This review examines the epidemiologic and experimental studies into the possible role ionizing radiation might play in Down Syndrome (trisomy 21). It is prompted by a report of a temporal cluster of cases of this chromosomal disorder observed in West Berlin exactly 9 mo after the radioactive cloud from Chernobyl passed. In approximately 90% of cases, Down Syndrome is due to the nondisjunction of chromosome 21, most often in the oocyte, which may be exposed to ionizing radiation during two separate periods: before the completion of the first meiosis or around the time of ovulation. Most epidemiologic studies into trisomies and exposure to ionizing radiation examine only the first period; the Chernobyl cluster is related to the second. Analysis of these epidemiologic results indicates that the possibility that ionizing radiation might be a risk factor in Down Syndrome cannot be excluded. The experimental results, although sometimes contradictory, demonstrate that irradiation may induce nondisjunction in oogenesis and spermatogenesis; they cannot, however, be easily extrapolated to humans. The weaknesses of epidemiologic studies into the risk factors for Down Syndrome at birth (especially the failure to take into account the trisomy cases leading to spontaneous abortion) are discussed. We envisage the utility and feasibility of new studies, in particular among women exposed to prolonged or repeated artificially-produced ionizing radiation.

Assessment of lumbar intervertebral disc glycosaminoglycan content by gadolinium-enhanced MRI before and after 21-days of head-down-tilt bedrest.

Directory of Open Access Journals (Sweden)

Timmo Koy

Full Text Available During spaceflight, it has been shown that intervertebral discs (IVDs increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC protocol before and after bedrest. The outcome measures were T1 and ΔT1. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T1-values of both scans (ΔT1 were computed. ΔT1 is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT1 (p<0.001 after bedrest in all IVDs, and in all areas of the IVDs. The ΔT1-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT1-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T1 before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT1 may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems

Sonographic large fetal head circumference and risk of cesarean delivery.

Science.gov (United States)

Lipschuetz, Michal; Cohen, Sarah M; Israel, Ariel; Baron, Joel; Porat, Shay; Valsky, Dan V; Yagel, Oren; Amsalem, Hagai; Kabiri, Doron; Gilboa, Yinon; Sivan, Eyal; Unger, Ron; Schiff, Eyal; Hershkovitz, Reli; Yagel, Simcha

2018-03-01

Persistently high rates of cesarean deliveries are cause for concern for physicians, patients, and health systems. Prelabor assessment might be refined by identifying factors that help predict an individual patient's risk of cesarean delivery. Such factors may contribute to patient safety and satisfaction as well as health system planning and resource allocation. In an earlier study, neonatal head circumference was shown to be more strongly associated with delivery mode and other outcome measures than neonatal birthweight. In the present study we aimed to evaluate the association of sonographically measured fetal head circumference measured within 1 week of delivery with delivery mode. This was a multicenter electronic medical record-based study of birth outcomes of primiparous women with term (37-42 weeks) singleton fetuses presenting for ultrasound with fetal biometry within 1 week of delivery. Fetal head circumference and estimated fetal weight were correlated with maternal background, obstetric, and neonatal outcome parameters. Elective cesarean deliveries were excluded. Multinomial regression analysis provided adjusted odds ratios for instrumental delivery and unplanned cesarean delivery when the fetal head circumference was ≥35 cm or estimated fetal weight ≥3900 g, while controlling for possible confounders. In all, 11,500 cases were collected; 906 elective cesarean deliveries were excluded. A fetal head circumference ≥35 cm increased the risk for unplanned cesarean delivery: 174 fetuses with fetal head circumference ≥35 cm (32%) were delivered by cesarean, vs 1712 (17%) when fetal head circumference cesarean delivery by an adjusted odds ratio of 1.75 (95% confidence interval, 1.4-2.18) controlling for gestational age, fetal gender, and epidural anesthesia. The rate of prolonged second stage of labor was significantly increased when either the fetal head circumference was ≥35 cm or the estimated fetal weight ≥3900 g, from 22.7% in the total

Gender Differences in Baroreflex Sensitivity after Bed Rest

Science.gov (United States)

Arzeno, Natalia M.; Stenger, M. B.; Ribeiro, L. C.; Lee, S. M.; Platts, S. H.

2009-01-01

Two potential contributing factors to post-spaceflight orthostatic intolerance are decreases in baroreflex sensitivity (BRS) and sympathetic nervous system response. The purpose of this study was to examine the shape of the BRS curve and sympathetic response to a wide range of blood pressures (BP) before and during 6 head-down bed rest (BR). METHODS: Normal volunteers were tested one day before BR (20M, 1 0F) and near BR days 30 (20M, 10F), 60 (16M, 8F), and 90 (1 0M, 5F). BP was pharmacologically manipulated by 10-min infusions of phenylephrine (PE) and sodium nitroprusside (SNP) at 3 increasing concentrations with a 20-min rest between PE and SNP. Electrocardiogram and continuous finger blood pressure were recorded. A blood sample was drawn at the end of each infusion to measure plasma norepinephrine levels. The spontaneous baroreflex slope (SBS), a measure of BRS, was calculated as the slope of a sequence of 3 or more beats in which the systolic BP (SBP) and following R-R interval (RR) both increased or decreased. The data included saturated responses at the upper but not the lower end of the BP range. Mean response curves were constructed using second-order mixed model analysis. Results are based on term significance in the models. RESULTS RR: RR was lower during BR than pre BR (pgenders were modeled by a linear response; compared to males, females had an attenuated (lower slope) RR response to changes in SBP (p=0.031). SBS: SBS vs SBP analysis showed a lower SBS during BR (pgender and BR. Not only do gender and BR baseline differences exist, but gender and BR also influence the slope and saturation of the BRS curves. Attenuated and saturating RR and SBS responses, as well as differences in baseline values, may contribute to the higher rates of orthostatic intolerance in women and after bed rest.

The Impact of Radiation Treatment Time on Survival in Patients With Head and Neck Cancer

International Nuclear Information System (INIS)

Shaikh, Talha; Handorf, Elizabeth A.; Murphy, Colin T.; Mehra, Ranee; Ridge, John A.; Galloway, Thomas J.

2016-01-01

Purpose: To assess the impact of radiation treatment time (RTT) in head and neck cancers on overall survival (OS) in the era of chemoradiation. Methods and Materials: Patients with diagnoses of tongue, hypopharynx, larynx, oropharynx, or tonsil cancer were identified by use of the National Cancer Database. RTT was defined as date of first radiation treatment to date of last radiation treatment. In the definitive setting, prolonged RTT was defined as >56 days, accelerated RTT was defined as 49 days, accelerated RTT was defined as <40 days, and standard RTT was defined as 40 to 49 days. We used χ"2 tests to identify predictors of RTT. The Kaplan-Meier method was used to compare OS among groups. Cox proportional hazards model was used for OS analysis in patients with known comorbidity status. Results: 19,531 patients were included; 12,987 (67%) had a standard RTT, 4,369 (34%) had an accelerated RTT, and 2,165 (11%) had a prolonged RTT. On multivariable analysis, accelerated RTT (hazard ratio [HR] 0.84; 95% confidence interval [CI] 0.73-0.97) was associated with an improved OS, and prolonged RTT (HR 1.25; 95% CI 1.14-1.37) was associated with a worse OS relative to standard RTT. When the 9,200 (47%) patients receiving definitive concurrent chemoradiation were examined, prolonged RTT (HR 1.29; 95% CI 1.11-1.50) was associated with a worse OS relative to standard RTT, whereas there was no significant association between accelerated RTT and OS (HR 0.76; 95% CI 0.57-1.01). Conclusion: Prolonged RTT is associated with worse OS in patients receiving radiation therapy for head and neck cancer, even in the setting of chemoradiation. Expeditious completion of radiation should continue to be a quality metric for the management of head and neck malignancies.

The importance of education to increase the use of bed nets in villages outside of Kinshasa, Democratic Republic of the Congo

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Ndjinga Julie K

2010-10-01

Full Text Available Abstract Background Malaria is the most prominent disease in the Democratic Republic of the Congo (DRC, and long-lasting insecticide-treated nets (LLINs have been distributed free of charge since 2006 to combat the disease. However, the success of this bed net campaign depends on sufficient bed net use in all age groups. This study was designed to examine the factors affecting bed net use in villages outside of Kinshasa. Methods Two villages along the Congo River, totalling 142 households with 640 residents, were surveyed using a standard questionnaire. The interview determined the number, ages, and sexes of family members; the education level of the family head; the number, colour, and type of nets owned; and the number of nets used in the previous night. The size of house was also measured, and numbers of rooms and beds were recorded. These variables were examined to reveal important factors that affect bed net use. Results A total of 469 nets were counted, and nearly all nets were white LLINs. Of these nets, 229 (48.8% nets were used by 284 (44.4% residents. Bed nets were used by over 90% of children 5 to 15 years of age, whereas less than 50% of the residents in other age groups used bed nets. The important variables affecting bed net use were numbers of beds and rooms in the house and the education level of the family head of household. Conclusion Education was the most important factor affecting bed net use in the villages outside Kinshasa. Development of an educational programme, particularly one directed toward parents, is necessary to reduce misconceptions and increase prevalence of bed net use among all age groups.

Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

Science.gov (United States)

Marquis, G. A.; Roy, A. G.

2012-02-01

This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.

The Impact of Radiation Treatment Time on Survival in Patients With Head and Neck Cancer

Energy Technology Data Exchange (ETDEWEB)

Shaikh, Talha [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Handorf, Elizabeth A. [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Murphy, Colin T. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Mehra, Ranee [Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Ridge, John A. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Galloway, Thomas J., E-mail: Thomas.Galloway@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States)

2016-12-01

Purpose: To assess the impact of radiation treatment time (RTT) in head and neck cancers on overall survival (OS) in the era of chemoradiation. Methods and Materials: Patients with diagnoses of tongue, hypopharynx, larynx, oropharynx, or tonsil cancer were identified by use of the National Cancer Database. RTT was defined as date of first radiation treatment to date of last radiation treatment. In the definitive setting, prolonged RTT was defined as >56 days, accelerated RTT was defined as <47 days, and standard RTT was defined as 47 to 56 days. In the postoperative setting, prolonged RTT was defined as >49 days, accelerated RTT was defined as <40 days, and standard RTT was defined as 40 to 49 days. We used χ{sup 2} tests to identify predictors of RTT. The Kaplan-Meier method was used to compare OS among groups. Cox proportional hazards model was used for OS analysis in patients with known comorbidity status. Results: 19,531 patients were included; 12,987 (67%) had a standard RTT, 4,369 (34%) had an accelerated RTT, and 2,165 (11%) had a prolonged RTT. On multivariable analysis, accelerated RTT (hazard ratio [HR] 0.84; 95% confidence interval [CI] 0.73-0.97) was associated with an improved OS, and prolonged RTT (HR 1.25; 95% CI 1.14-1.37) was associated with a worse OS relative to standard RTT. When the 9,200 (47%) patients receiving definitive concurrent chemoradiation were examined, prolonged RTT (HR 1.29; 95% CI 1.11-1.50) was associated with a worse OS relative to standard RTT, whereas there was no significant association between accelerated RTT and OS (HR 0.76; 95% CI 0.57-1.01). Conclusion: Prolonged RTT is associated with worse OS in patients receiving radiation therapy for head and neck cancer, even in the setting of chemoradiation. Expeditious completion of radiation should continue to be a quality metric for the management of head and neck malignancies.

Variations in the presentation of aphasia in patients with closed head injuries.

LENUS (Irish Health Repository)

Kavanagh, Dara Oliver

2012-01-31

Impairments of speech and language are important consequences of head injury as they compromise interaction between the patient and others. A large spectrum of communication deficits can occur. There are few reports in the literature of aphasia following closed head injury despite the common presentation of closed head injury. Herein we report two cases of closed head injuries with differing forms of aphasia. We discuss their management and rehabilitation and present a detailed literature review on the topic. In a busy acute surgical unit one can dismiss aphasia following head injury as behaviour related to intoxication. Early recognition with prolonged and intensive speech and language rehabilitation therapy yields a favourable outcome as highlighted in our experience. These may serve as a reference for clinicians faced with this unusual outcome.

Variations in the Presentation of Aphasia in Patients with Closed Head Injuries

Directory of Open Access Journals (Sweden)

Dara Oliver Kavanagh

2010-01-01

Full Text Available Impairments of speech and language are important consequences of head injury as they compromise interaction between the patient and others. A large spectrum of communication deficits can occur. There are few reports in the literature of aphasia following closed head injury despite the common presentation of closed head injury. Herein we report two cases of closed head injuries with differing forms of aphasia. We discuss their management and rehabilitation and present a detailed literature review on the topic. In a busy acute surgical unit one can dismiss aphasia following head injury as behaviour related to intoxication. Early recognition with prolonged and intensive speech and language rehabilitation therapy yields a favourable outcome as highlighted in our experience. These may serve as a reference for clinicians faced with this unusual outcome.

Tension in the tie-down chains of a shipping container for hazardous material

International Nuclear Information System (INIS)

Lo, T.Y.

1995-01-01

Chains are frequently used to tie the shipping containers of hazardous material to a truck bed. The tie-down system is nonlinear when the container is subjected to a triaxial force during transit. It is nonlinear because chains cannot carry compressive force, and the base of the container may partially lift off from the truck bed. A method was developed to calculate the amount of tension in the chains. This methodology includes three assumptions: (1) No friction exists between the container and the truck bed; (2) The container and the truck bed are rigid; and (3) All chains are properly tightened (i.e., no slacks) during preparation for shipment. The methodology employs an iterative process of a linear tie-down system. This linear system is derived from the nonlinear system with two additional assumptions: (a) All chains can carry compression as well as tension; and (b) There is a point contact between the container and the truck bed. This linear system has a closed-form solution. After the first solution of the linear system is obtained, the unreasonable, or physically impossible, rotational degree of freedom of the container and the chains with compressive force are eliminated in the follow-up iterative calculations using the same linear system. Unreasonable rotation is detected when the results indicate a rotation of the container into the truck bed. Zero rotational value is assigned to this degree of freedom in the follow-up iterations. For chains under compression, the chain length is replaced with a fictitiously large value because a long chain carries essentially no load. This process usually needs only two or three iterations and can easily be carried out in a spread sheet using such programs as Microsoft Excel or LOTUS 123

Effects of rehydration on +Gz tolerance after 14-days' bed rest.

Science.gov (United States)

Greenleaf, J. E.; Van Beaumont, W.; Bernauer, E. M.; Haines, R. F.; Sandler, H.; Staley, R. W.; Young, H. L.; Yusken, J. W.

1973-01-01

Investigation of the magnitude of reduction in human tolerance to centrifugation following 2 weeks of bed rest with moderate daily exercise. The degree of hypovolemia associated with these exposures is assessed, and the possibility to improve or to return to control levels the tolerance to acceleration forces acting in the head-to-foot direction through rehydration prior to acceleration is explored.

The effect of patient migration in bed on torso elevation.

Science.gov (United States)

Wiggermann, Neal; Kotowski, Susan; Davis, Kermit; VanGilder, Catherine

2015-01-01

Elevating the hospital head of bed (HOB) to at least 30° is recommended practice to reduce the risk of ventilator-associated pneumonia (VAP) in mechanically ventilated patients. However, this common practice prescribes the position of the bed and not of the patient, which could be significantly different. The aim of this research was to determine the relationship between patient migration in bed and anatomic torso angle. Ten healthy participants were positioned in a hospital bed that was raised from flat to 30° and 45° HOB elevations. Prior to bed movement, participants were aligned to different locations along the length of the bed to represent different amounts of migration. A motion capture system was used to measure torso angle and migration toward the foot of the bed. The relationship between torso angle and migration was estimated by linear regression. Patient migration resulted in lower torso angles for both 30° and 45° HOB articulations. A migration of 10 cm resulted in a loss of 9.1° and 13.0° of torso angle for HOB articulations of 30° and 45°, respectively (for 30° articulations: (Equation is included in full-text article.)= -0.91, R = .96; for 45° articulations: (Equation is included in full-text article.)= -1.30, R = .98). Migration toward the foot of the bed flattens the torso. To maintain a torso angle that is likely to protect against VAP, healthcare providers need to manage both HOB angle and migration. Protocols and equipment that minimize patient migration will help support effective clinical practice. Future research on patient migration, as it relates to VAP or other outcomes, should measure patient torso angle to allow accurate translation of the results to care practice.

Protective head-cooling during cardiac arrest and cardiopulmonary resuscitation: the original animal studies

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Eric W. Brader

2010-02-01

Full Text Available Prolonged standard cardiopulmonary resuscitation (CPR does not reliably sustain brain viability during cardiac arrest. Pre-hospital adjuncts to standard CPR are needed in order to improve outcomes. A preliminary dog study demonstrated that surface cooling of the head during arrest and CPR can achieve protective levels of brain hypothermia (30°C within 10 minutes. We hypothesized that protective head-cooling during cardiac arrest and CPR improves neurological outcomes. Twelve dogs under light ketamine-halothane-nitrous oxide anesthesia were arrested by transthoracic fibrillation. The treated group consisted of six dogs whose shaven heads were moistened with saline and packed in ice immediately after confirmation of ventricular fibrillation. Six control dogs remained at room temperature. All 12 dogs were subjected to four minutes of ventricular fibrillation and 20 minutes of standard CPR. Spontaneous circulation was restored with drugs and countershocks. Intensive care was provided for five hours post-arrest and the animals were observed for 24 hours. In both groups, five of the six dogs had spontaneous circulation restored. After three hours, mean neurological deficit was significantly lower in the treated group (P=0.016, with head-cooled dogs averaging 37% and the normothermic dogs 62%. Two of the six head-cooled dogs survived 24 hours with neurological deficits of 9% and 0%, respectively. None of the control group dogs survived 24 hours. We concluded that head-cooling attenuates brain injury during cardiac arrest with prolonged CPR. We review the literature related to the use of hypothermia following cardiac arrest and discuss some promising approaches for the pre-hospital setting.

Use of an Android application “clinometer” for measurement of head down tilt given during subarachnoid block

Science.gov (United States)

Dixit, RB; Neema, MM

2016-01-01

Context: Head down tilt is given to patients after sub arachnoid block for adjustment of height of block. However, the amount of tilt given is subjective and cannot be documented. Aims: We used an android application named “clinometer” to measure exact degree of tilt given by anesthesiologists as their routine practice. Settings and Design: This observational study, at a medical college hospital, was done in 130 patients given sub arachnoid block for lower abdominal surgeries. Materials and Methods: We observed and documented vital data of patients and measured tilt given by application “clinometer.” Results: We observed that the application was easy to use and measured tilt each time. The result obtained can be documented, digitally saved and transferred. In 130 patients studied, we observed incidence of degree of tilt as follows: 6-8° tilt in 38 patients (29.23%), 8-10 in 36 patients (27.69%), 10-12 in 30 patients (23.08%), 12-14 in 12 patients (9.23%) and 14-16° tilt in 14 patients (10.77%). Use of application was received with enthusiasm by practicing anesthesiologists. Various possible uses of this application are discussed. PMID:26955307

Adaptation to prolonged bedrest in man: A compendium of research. [bibliographies on clinical medicine and human pathology

Science.gov (United States)

Greenleaf, J. E.; Greenleaf, C. J.; Vanderveer, D.; Dorchak, K. J.

1976-01-01

A compilation of major studies that describe the clinical observations and elucidate the physiological mechanisms of the adaptive process of man undergoing prolonged bed rest is presented. Additional studies are included that provide background information in the form of reviews or summaries of the process. Wherever possible a detailed annotation is provided under the subheadings: (1) purpose, (2) procedure and methods, (3) results, and (4) conclusions. Additional references are provided in a selected bibliography.

Bed net use and associated factors in a rice farming community in Central Kenya

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Kabuage Lucy

2009-04-01

Full Text Available Abstract Background Use of insecticide-treated nets (ITNs continues to offer potential strategy for malaria prevention in endemic areas. However their effectiveness, sustainability and massive scale up remain a factor of socio-economic and cultural variables of the local community which are indispensable during design and implementation stages. Methods An ethnographic household survey was conducted in four study villages which were purposefully selected to represent socio-economic and geographical diversity. In total, 400 households were randomly selected from the four study villages. Quantitative and qualitative information of the respondents were collected by use of semi-structured questionnaires and focus group discussions. Results Malaria was reported the most frequently occurring disease in the area (93% and its aetiology was attributed to other non-biomedical causes like stagnant water (16%, and long rains (13%. Factors which significantly caused variation in bed net use were occupant relationship to household head (χ2 = 105.705; df 14; P = 0.000, Age (χ2 = 74.483; df 14; P = 0.000, village (χ2 = 150.325; df 6; P = 0.000, occupation (χ2 = 7.955; df 3; P = 0.047, gender (χ2 = 4.254; df 1; P = 0.039 and education levels of the household head or spouse (χ2 = 33.622; df 6; P = 0.000. The same variables determined access and conditions of bed nets at household level. Protection against mosquito bite (95% was the main reason cited for using bed nets in most households while protection against malaria came second (54%. Colour, shape and affordability were some of the key potential factors which determined choice, use and acceptance of bed nets in the study area. Conclusion The study highlights potential social and economic variables important for effective and sustainable implementation of bed nets-related programmes in Sub-Saharan Africa.

Steam Generator Group Project. Task 6. Channel head decontamination

International Nuclear Information System (INIS)

Allen, R.P.; Clark, R.L.; Reece, W.D.

1984-08-01

The Steam Generator Group Project utilizes a retired-from-service pressurized-water-reactor steam generator as a test bed and source of specimens for research. An important preparatory step to primary side research activities was reduction of the radiation field in the steam generator channel head. This task report describes the channel head decontamination activities. Though not a programmatic research objective it was judged beneficial to explore the use of dilute reagent chemical decontamination techniques. These techniques presented potential for reduced personnel exposure and reduced secondary radwaste generation, over currently used abrasive blasting techniques. Two techniques with extensive laboratory research and vendors prepared to offer commercial application were tested, one on either side of the channel head. As indicated in the report, both techniques accomplished similar decontamination objectives. Neither technique damaged the generator channel head or tubing materials, as applied. This report provides details of the decontamination operations. Application system and operating conditions are described

Analytical verification of requirements for safe and timely lay-down of ...

African Journals Online (AJOL)

Analytical verification of requirements for safe and timely lay-down of an offshore slay pipeline abandonment head during some pipe-lay stops: a case study of Forcados Yokri integrated pipeline project in Nigerian shallow offshore.

Global hospital bed utilization crisis. A different approach.

Science.gov (United States)

Waness, Abdelkarim; Akbar, Jalal U; Kharal, Mubashar; BinSalih, Salih; Harakati, Mohammed

2010-04-01

To test the effect of improved physician availability on hospital bed utilization. A prospective cohort study was conducted from 1st January 2009 to 31st March 2009 in the Division of Internal Medicine (DIM), King Abdul-Aziz Medical City (KAMC), Riyadh, Kingdom of Saudi Arabia. Two clinical teaching units (CTU) were compared head-to-head. Each CTU has 3 consultants. The CTU-control provides standard care, while the CTU-intervention was designed to provide better physician-consultant availability. Three outcomes were evaluated: patient outsourcing to another hospital, patient discharge during weekends, and overall admissions. Statistical analysis was carried out by electronic statistics calculator from the Center for Evidence-Based Medicine. Three hundred and thirty-four patients were evaluated for admission at the Emergency Room by both CTU's. One hundred and eighty-three patients were seen by the CTU-control, 6 patients were outsourced, and 177 were admitted. One hundred fifty-one patients were seen by the CTU-intervention: 39 of them were outsourced, and 112 were admitted. Forty-eight weekend patient discharges occurred during this period of time: 21 by CTU-control, and 27 by CTU-intervention. Analysis for odds ratio in both the rate of outsourcing, and weekend discharges, showed statistical significance in favor of the intervention group. The continuous availability of a physician-consultant for patient admission evaluation, outsourcing, or discharge during regular weekdays and weekends at DIM, KAMC proved to have a positive impact on bed utilization.

Implementation of true continuous bed motion in 2-D and 3-D whole-body PET scanning

Science.gov (United States)

Dahlbom, M.; Reed, J.; Young, J.

2001-08-01

True continuous axial bed motion has been implemented on a high-resolution positron emission tomography (PET) scanner for use in both two-dimensional (2-D) and three-dimensional (3-D) acquisition modes. This has been accomplished by modifications in the bed motion controller firmware and by acquiring data in list mode. The new bed controller firmware was shown to provide an accurate and constant bed speed down to 0.25 mm/s with a moderate patient weight load. The constant bed motion eliminates previously reported dead-time due to bed positioning when using small discrete bed steps. The continuous bed motion was tested on uniform phantoms, in 2-D and 3-D. As a result of the continuous axial motion, a uniform axial sensitivity is achieved. This was also reflected in the reconstructed images, which showed an improvement in axial image uniformity (1.4% for continuous sampling, 5.0% for discrete) as well as an improvement in %SD uniformity in comparison to conventional step-and-shoot acquisitions. The use of the continuous axial motion also provide slight improvements in 2-D emission and transmission scanning, resulting in an overall improved image quality in whole-body PET.

SCDAP/RELAP5 Modeling of Movement of Melted Material Through Porous Debris in Lower Head

International Nuclear Information System (INIS)

Siefken, L. J.

1998-01-01

Designs are described for implementing models for calculating the movement of melted material through the interstices in a matrix of porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and nonporous debris that results from core material slumping into the lower head during a severe accident in a Light Water Reactor. Currently, the COUPLE model has no capability to model the movement of material that melts within a matrix of porous material. The COUPLE model also does not have the capability to model the movement of liquefied core plate material that slumps onto a porous debris bed in the lower head. In order to advance beyond the assumption the liquefied material always remains stationary, designs are developed for calculations of the movement of liquefied material through the interstices in a matrix of porous material. Correlations are identified for calculating the permeability of the porous debris and for calculating the rate of flow of liquefied material through the interstices in the debris bed. Correlations are also identified for calculating the relocation of solid debris that has a large amount of cavities due to the flowing away of melted material. Equations are defined for calculating the effect on the temperature distribution in the debris bed of heat transported by moving material and for changes in effective thermal conductivity and heat capacity due to the movement of material. The implementation of these models is expected to improve the calculation of the material distribution and temperature distribution of debris in the lower head for cases in which the debris is porous and liquefied material is present within the porous debris

The Definition of a Prolonged Intensive Care Unit Stay for Spontaneous Intracerebral Hemorrhage Patients: An Application with National Health Insurance Research Database

Directory of Open Access Journals (Sweden)

Chien-Lung Chan

2014-01-01

Full Text Available Introduction. Length of stay (LOS in the intensive care unit (ICU of spontaneous intracerebral hemorrhage (sICH patients is one of the most important issues. The disease severity, psychosocial factors, and institutional factors will influence the length of ICU stay. This study is used in the Taiwan National Health Insurance Research Database (NHIRD to define the threshold of a prolonged ICU stay in sICH patients. Methods. This research collected the demographic data of sICH patients in the NHIRD from 2005 to 2009. The threshold of prolonged ICU stay was calculated using change point analysis. Results. There were 1599 sICH patients included. A prolonged ICU stay was defined as being equal to or longer than 10 days. There were 436 prolonged ICU stay cases and 1163 nonprolonged cases. Conclusion. This study showed that the threshold of a prolonged ICU stay is a good indicator of hospital utilization in ICH patients. Different hospitals have their own different care strategies that can be identified with a prolonged ICU stay. This indicator can be improved using quality control methods such as complications prevention and efficiency of ICU bed management. Patients’ stay in ICUs and in hospitals will be shorter if integrated care systems are established.

Using Passive Polyethylene Samplers to Evaluate Chemical Activities Controlling Fluxes and Bioaccumulation of Organic Contaminants in Bed Sediments

Science.gov (United States)

2010-11-01

often yielding uncertain information regarding the degree of hazard and the spatial extent of the problem. Subsequent remediation commonly involves...suited to sampling organic contaminants across bed-water interfaces and down into the sediment bed. The methodology must yield data that are more...surrogate standards were Soxhlet extracted for 24 hr using 450 mL of dichloromethane. Extracts were reduced to approximately 10 mL using the rotary

Infant's bed climate and bedding in the Japanese home.

Science.gov (United States)

Nakamura Ikeda, Rie; Fukai, Kiyoko; Okamoto Mizuno, Kazue

2012-06-01

to assess the bed climate of infants in their homes in Japan. descriptive, exploratory, non-experimental research design. the data were collected at the participants' homes under normal circumstances. nineteen healthy infants between the ages of two and five months. Their mothers, who joined a parenting class organised by a maternity clinic in Okayama, Japan, consented to participate in this study. we visited the infants' homes and interviewed their mothers concerning the types and use of bedding. The temperature and relative humidity of the bed climate at the back and foot of the bedding, and in the room were measured every minute for four consecutive days. Differences among the bed climates measured during three seasons (spring, summer, and autumn) were assessed by one-way analysis of variance. The bed temperature was higher for infants than for adults. No significant difference in temperature was noted among the three seasons. The bed temperature was about 36.0°C when waterproof sheets and futon mattresses for children or adult were used. The average relative humidity of the bed climate at the back was highest in summer, followed by that in spring and autumn; the differences were significant. The use of waterproof sheets and futon mattresses for children in summer increased the relative humidity to 80% or more. The use of infant beds, sunoko drainboards, and cotton futon mattresses in summer was effective in reducing the bed humidity. these results suggest that nurse-midwives should advise the parents on comfortable bed climates for their infants, as well as how to select and use bedding for them. Copyright © 2010 Elsevier Ltd. All rights reserved.

Psychomotor performance during a 28 day head-down tilt with and without lower body negative pressure

Science.gov (United States)

Traon, A. Pavy-le; de Feneyrols, A. Rous; Cornac, A.; Abdeseelam, R.; N'uygen, D.; Lazerges, M.; Güell, A.; Bes, A.

Several factors may affect psychomotor performance in space: sensory-motor changes, sleep disturbances, psychological modifications induced by the social isolation and confinement. However, psychomotor performance is difficult to assess. A battery of standardized and computerized tests, so-called "Automated Portable Test System" (APTS) was devised to ascertain the cognitive, perceptive and motor abilities and their possible fluctuations according to environmental effects. Antiorthostatic bedrest, often used to simulate weightlessness, (particularly cardiovascular modifications) also constitutes a situation of social confinement and isolation. During two bedrest experiments (with head-down tilt of -6°) of 28 days each, we intended to assess psychomotor performance of 6 males so as to determine whether: —on the one hand, it could be altered by remaining in decubitus; —on the other, the Lower Body Negative Pressure sessions, designed to prevent orthostatic intolerance back on Earth, could improve the performance. To accomplish this, part of the APTS tests as well as an automated perceptive attention test were performed. No downgrading of psychomotor performance was observed. On the contrary, the tasks were more accurately performed over time. In order to assess the experimental conditions on the acquisition phase, the learning curves were modelled. A beneficial effect of the LBNP sessions on simple tests involving the visual-motor coordination and attention faculties can only be regarded as a mere trend. Methods used in this experiment are also discussed.

Predictors of successful weaning from prolonged mechanical ventilation in Taiwan.

Science.gov (United States)

Wu, Yao-Kuang; Kao, Kuo-Chin; Hsu, Kuang-Hung; Hsieh, Meng-Jer; Tsai, Ying-Huang

2009-08-01

For adult patients on prolonged mechanical ventilation (PMV, >/=21 days), successful weaning has been attributed to various factors. The purpose of this study was to describe patient outcomes, weaning rates and factors in successful weaning at a hospital-based respiratory care center (RCC) in Taiwan. This was a retrospective observational study performed in a 24-bed RCC over six years. A total of 1307 patients on PMV were included in the study. The overall survival rate was 62%. Fifty-six percent of patients were successfully weaned. Unsuccessfully weaned patients had higher MICU transfer rates, higher Acute Physiology and Chronic Health Evaluation II scores, longer duration of RCC stay, higher rates of being bed-ridden prior to admission, increased hemodialysis rates, higher modified Glasgow Coma Scale scores, higher rapid shallow breathing index, lower inspiratory pressure at residual volume (PImax) and lower blood urea nitrogen (BUN) and creatinine levels. Factors found to be associated with unsuccessful weaning were length of RCC stay (OR=1.04, Pventilator independence can be achieved in an RCC setting as an alternative to ICU care. Factors associated with unsuccessful weaning included longer duration of RCC stay, elevated BUN levels and lower modified GCS scores, serum albumin and PImax levels.

Effects of traction on the blood circulation of femoral head: DSA study on a canine model

International Nuclear Information System (INIS)

Yang Xiujun; Xiao Jian; Ren Qile; Fu Shiping; Li Wei; Xiao Xiangsheng

2010-01-01

Objective: To study the influence of traction on the blood circulation of femur head and its evaluation by DSA. Methods: Using micro-catheter, transfemoral selective femoral circumflex arteriography in 22 healthy dogs was performed in unilateral hip before (Group A, n=22) and immediately (Group B, n=22), 30 (Group D, n=22), 60 (Group E, n=20), 90 (Group F, n=10), 120 (Group G, n= 10) minutes during 2 kg skin hip traction, and immediately after traction removal (Group H, I, J, L and O) , and 30 minutes after traction removal with 60, 90 and 120 minutes continuous traction (Group K, M and P) , and 60 minutes after traction removal with 90 and 120 minutes continuous traction (Group N and Q). DSA was also performed immediately during 4 kg weight traction before continuous traction in 12 hips (Group C). Blood circulation of the femoral head was evaluated mainly by observing its perfusion and time of circulation. Femur head perfusion was assessed as good scoring 3, poor scoring 2 and extremely poor scoring 1. Femur head circulation time was assessed as normal scoring 3, prolonged scoring 2 and remarkably prolonged scoring 1. Analysis of variance was employed for analysis of the angiographic findings between different groups. Results: Good femoral head perfusion in Group A to Q was 22, 0, 0, 0, 0, 0, 0, 22, 22, 1, 18, 0, 0, 8, 0, 0 and 1 hips respectively, poor one was 0, 22, 8, 22, 15, 4, 1, 0, 0, 15, 2, 4, 6, 2, 1, 3 and 8 hips, respectively, extremely poor one was 0, 0, 4, 0, 5, 6, 9, 0, 0, 4, 0, 6, 4, 0, 9, 7 and 1 hips, respectively; and normal femoral head blood circulation time was 22, 0, 0, 0, 0, 0, 0, 22, 22, 1, 18, 0, 0, 8, 0, 0 and 1 hips, respectively, prolonged one was 0, 22, 9, 22, 15, 4, 2, 0, 0, 15, 2, 5, 7, 2, 2, 4 and 8 hips, respectively, remarkably prolonged one was 0, 0, 3, 0, 5, 6, 8, 0, 0, 4, 0, 5, 3, 0, 8, 6 and 1 hips, respectively. F value of femoral head perfusion among group A and B,group B and C, group B, D, E, F and G, Group H, I, J, L and O

Technology assessment of automated atlas based segmentation in prostate bed contouring

Directory of Open Access Journals (Sweden)

Sexton Tracy

2011-09-01

Full Text Available Abstract Background Prostate bed (PB contouring is time consuming and associated with inter-observer variability. We evaluated an automated atlas-based segmentation (AABS engine in its potential to reduce contouring time and inter-observer variability. Methods An atlas builder (AB manually contoured the prostate bed, rectum, left femoral head (LFH, right femoral head (RFH, bladder, and penile bulb of 75 post-prostatectomy cases to create an atlas according to the recent RTOG guidelines. 5 other Radiation Oncologists (RO and the AABS contoured 5 new cases. A STAPLE contour for each of the 5 patients was generated. All contours were anonymized and sent back to the 5 RO to be edited as clinically necessary. All contouring times were recorded. The dice similarity coefficient (DSC was used to evaluate the unedited- and edited- AABS and inter-observer variability among the RO. Descriptive statistics, paired t-tests and a Pearson correlation were performed. ANOVA analysis using logit transformations of DSC values was calculated to assess inter-observer variability. Results The mean time for manual contours and AABS was 17.5- and 14.1 minutes respectively (p = 0.003. The DSC results (mean, SD for the comparison of the unedited-AABS versus STAPLE contours for the PB (0.48, 0.17, bladder (0.67, 0.19, LFH (0.92, 0.01, RFH (0.92, 0.01, penile bulb (0.33, 0.25 and rectum (0.59, 0.11. The DSC results (mean, SD for the comparison of the edited-AABS versus STAPLE contours for the PB (0.67, 0.19, bladder (0.88, 0.13, LFH (0.93, 0.01, RFH (0.92, 0.01, penile bulb (0.54, 0.21 and rectum (0.78, 0.12. The DSC results (mean, SD for the comparison of the edited-AABS versus the expert panel for the PB (0.47, 0.16, bladder (0.67, 0.18, LFH (0.83, 0.18, RFH (0.83, 0.17, penile bulb (0.31, 0.23 and rectum (0.58, 0.09. The DSC results (mean, SD for the comparison of the STAPLE contours and the 5 RO are PB (0.78, 0.15, bladder (0.96, 0.02, left femoral head (0.87, 0

Bed Bugs

Science.gov (United States)

Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

Peripherally Inserted Central Catheters (PICCs) and Potential Cost Savings and Shortened Bed Stays In an Acute Hospital Setting.

LENUS (Irish Health Repository)

O’Brien, C

2018-01-01

Peripheral inserted central catheters (PICCs) have increasingly become the mainstay of patients requiring prolonged treatment with antibiotics, transfusions, oncologic IV therapy and total parental nutrition. They may also be used in delivering a number of other medications to patients. In recent years, bed occupancy rates have become hugely pressurized in many hospitals and any potential solutions to free up beds is welcome. Recent introductions of doctor or nurse led intravenous (IV) outpatient based treatment teams has been having a direct effect on early discharge of patients and in some cases avoiding admission completely. The ability to deliver outpatient intravenous treatment is facilitated by the placement of PICCs allowing safe and targeted treatment of patients over a prolonged period of time. We carried out a retrospective study of 2,404 patients referred for PICCs from 2009 to 2015 in a university teaching hospital. There was an exponential increase in the number of PICCs requested from 2011 to 2015 with a 64% increase from 2012 to 2013. The clear increase in demand for PICCs in our institution is directly linked to the advent of outpatient intravenous antibiotic services. In this paper, we assess the impact that the use of PICCs combined with intravenous outpatient treatment may have on cost and hospital bed demand. We advocate that a more widespread implementation of this service throughout Ireland may result in significant cost savings as well as decreasing the number of patients on hospital trollies.

Passive Cushiony Biomechanics of Head Protection in Falling Geckos

Directory of Open Access Journals (Sweden)

Hao Wang

2018-01-01

Full Text Available Gekko geckos are capable to crawl on the steep even on upside-down surfaces. Such movement, especially at great altitude, puts them at high risks of incidentally dropping down and inevitable body or head impactions, though they may trigger air-righting reaction (ARR to attenuate the landing shocks. However, the air-righting ability (ARA in Gekko geckos is not fully developed. The implementation of ARR in some geckos is quite slow; and for those without tails, the ARR is even unobservable. Since ARA is compromised in Gekko geckos, there must be some other mechanisms responsible for protecting them from head injuries during falls. In this study, we looked into a Gekko gecko’s brain to study its internal environment and structure, using the magnetic resonance imaging (MRI technique. The results showed that the brain parenchyma was fully surrounded by the cerebrospinal fluid (CSF in the skull. A succulent characteristic was presented, which meant the intracalvarium was significantly occupied by the CSF, up to 45% in volume. Then a simplified three-dimensional finite element model was built, and a dynamic simulation was conducted to evaluate the mechanical property of this succulent characteristic during the head impactions. These implied the succulent characteristic may play certain roles on the self-protection in case of head impaction, which is adaptable to the Gekko gecko’s locomotion and behavior.

Bed agglomeration characteristics of palm shell and corncob combustion in fluidized bed

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Sricharoon, Panchan; Tia, Suvit

2011-01-01

Bed particle agglomeration was studied experimentally in an atmospheric laboratory scale fluidized bed combustor using quartz sand as bed material. Palm shell and corncob were tested. The objectives of the study were (i) to describe the contributions of the biomass ash properties and the operating conditions on the bed agglomeration tendency in term of the bed defluidization time (t def ) and the extent of potassium accumulation in the bed (K/Bed) and (ii) to further elucidate the ash inorganic behaviors and the governing bed agglomeration mechanisms. Defluidization caused by the bed agglomeration was experienced in all experiments during combustion of these biomasses, as a consequence of the presence of potassium in biomass. The experimental results indicated that biomass ash characteristics were the significant influence on the bed agglomeration. The increasing bed temperature, bed particle size and static bed height and the decreasing fluidizing air velocity enhanced the bed agglomeration tendency. The SEM/EDS analyses on the agglomerates confirmed that the agglomeration was attributed to the formation of potassium silicate liquid enriched on the surface of quartz sand particles in conjunction with the high surface temperature of the burning biomass char particles. Thermodynamic examination based on the phase diagram analysis confirmed that the molten phase formation was responsible for the agglomeration. In this study, the high molten ash fraction resulting from the high potassium content in biomass promoted the agglomeration and thus defluidization. - Highlights: → Palm shell and corncob of Thailand are tested their bed agglomeration behaviors during fluidized bed combustion. → The increase of bed temperature, bed particle size and static bed height and the decrease of air velocity enhance bed agglomeration. → The formation of ash derived potassium silicate melts enriched on sand surface is the key process. → The collision between char and sand

The characteristics of bed agglomeration during fluidized bed combustion of eucalyptus bark

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Tia, Suvit

2015-01-01

The bed agglomeration behaviors were investigated experimentally when eucalyptus bark was burning tested in a laboratory scale fluidized bed reactor. The focuses of this work were the influences of operating conditions and bed materials on the bed agglomeration tendency and the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease in measured bed pressure. The growth of bed particle and accumulation of agglomerates during combustion provided the partial to complete defluidization. The defluidization was promoted by the increase of bed temperature and bed particle size, and the decrease of fluidizing air velocity. The SEM-EDS analyses revealed that the bed agglomeration was mainly attributed to the formation of potassium silicate compounds as liquid phase during the combustion. This was initiated by the chemical reaction between the bed particle and the released ash constituents. In this study, the inorganic migration from fuel particle to bed particle was likely dominated by the condensation/reaction. The thermodynamic examination by ternary phase diagram analysis corroborated that the liquid phase formation of the ash derived materials controlled the agglomeration. The alumina sand prevented the bed agglomeration since it was inactive in the formation of viscous molten substances during combustion at the observed temperatures. - Highlights: • The behaviors of bed agglomeration were studied during the fluidized bed combustion of eucalyptus bark. • The increase in bed temperature and sand size, and the decrease of air velocity promoted bed defluidization. • The formation of molten potassium silicate compounds conduced to the bed agglomeration. • Condensation/reaction was the dominant inorganic migration mechanism from fuel particle to bed particle. • The alumina sand prevented effectively the bed

Experimental investigation of multidimensional cooling effects on the coolability of a debris bed

International Nuclear Information System (INIS)

Rashidi, M.; Kulenovici, R.; Laurieni, E.

2011-01-01

During a severe accident in a light water reactor, the core can melt and be relocated to the lower plenum of the reactor pressure vessel. There it can form a particulate debris bed due to the possible presence of water. Within the reactor safety research, the removal of decay heat from a debris bed (formed from corium and residual water) is of great importance. In order to investigate experimentally the long-term coolability of debris beds, the down-scaled non nuclear test facility DEBRIS has been established at IKE. The major objectives of the experimental investigations at this test facility are the determination of local pressure drops for steady state boiling to check friction laws, the determination of dryout heat fluxes under various conditions for validation of numerical models, and the analysis of quenching processes of dry hot debris beds. A large number of 1D-experiments were carried out to investigate the coolability limits for different bed configurations at various thermohydraulic conditions, and to validate numerical models which can be used in reactor safety studies. Analyses based on one-dimensional configurations underestimate the coolability in realistic multidimensional configurations, where lateral water access and water inflow via bottom regions are favored. This paper presents 2D experimental results, based on various kinds of water inflow conditions into the bed, boiling and dryout tests with different bed configurations and different system pressures. Preliminary results show that the system pressure has no significant effect on the fundamental shape of the pressure gradient inside the bed, whereas with increasing system pressure the coolability limits are increased

Exercise Effects on the Brain and Sensorimotor Function in Bed Rest

Science.gov (United States)

Koppelmans, V.; Cassady, K.; De Dios, Y. E.; Szecsy, D.; Gadd, N.; Wood, S. J.; Reuter-Lorenz, R. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.;

Effects of two hospital bed design features on physical demands and usability during brake engagement and patient transportation: a repeated measures experimental study.

Science.gov (United States)

Kim, Sunwook; Barker, Linsey M; Jia, Bochen; Agnew, Michael J; Nussbaum, Maury A

2009-03-01

Work-related musculoskeletal disorders (WMSDs) are prevalent among healthcare workers worldwide. While existing research has focused on patient-handling techniques during activities which require direct patient contact (e.g., patient transfer), nursing tasks also involve other patient-handling activities, such as engaging bed brakes and transporting patients in beds, which could render healthcare workers at risk of developing WMSDs. Effectiveness of hospital bed design features (brake pedal location and steering-assistance) was evaluated in terms of physical demands and usability during brake engagement and patient transportation tasks. Two laboratory-based studies were conducted. In simulated brake engagement tasks, three brake pedal locations (head-end vs. foot-end vs. side of a bed) and two hands conditions (hands-free vs. hands-occupied) were manipulated. Additionally, both in-room and corridor patient transportation tasks were simulated, in which activation of steering-assistance features (5th wheel and/or front wheel caster lock) and two patient masses were manipulated. Nine novice participants were recruited from the local student population and community for each study. During brake engagement, trunk flexion angle, task completion time, and questionnaires were used to quantify postural comfort and usability. For patient transportation, dependent measures were hand forces and questionnaire responses. Brake pedal locations and steering-assistance features in hospital beds had significant effects on physical demands and usability during brake engagement and patient transportation tasks. Specifically, a brake pedal at the head-end of a bed increased trunk flexion by 74-224% and completion time by 53-74%, compared to other pedal locations. Participants reported greater overall perceived difficulty and less postural comfort with the brake pedal at the head-end. During in-room transportation, participants generally reported "Neither Low nor High" physical demands

Electromyographic evaluation of high-intensity elastic resistance exercises for lower extremity muscles during bed rest

DEFF Research Database (Denmark)

Vinstrup, Jonas; Skals, Sebastian; Calatayud, Joaquin

2017-01-01

PURPOSE: Prolonged hospital bed rest after severe injury or disease leads to rapid muscle atrophy and strength loss. Therefore, the main aim of this study was to evaluate the efficacy of lower extremity strengthening exercises using elastic resistance that can be performed while lying in a hospit......, the present study has the potential to provide a reference table of exercises to select from when individualizing and progressing strengthening exercises during the early rehabilitation of bedridden individuals....

HEAD MOVEMENT DURING WALKING IN THE CAT

Science.gov (United States)

ZUBAIR, HUMZA N.; BELOOZEROVA, IRINA N.; SUN, HAI; MARLINSKI, VLADIMIR

2016-01-01

Knowledge of how the head moves during locomotion is essential for understanding how locomotion is controlled by sensory systems of the head. We have analyzed head movements of the cat walking along a straight flat pathway in the darkness and light. We found that cats' head left-right translations, and roll and yaw rotations oscillated once per stride, while fore-aft and vertical translations, and pitch rotations oscillated twice. The head reached its highest vertical positions during second half of each forelimb swing, following maxima of the shoulder/trunk by 20–90°. Nose-up rotation followed head upward translation by another 40–90° delay. The peak-to-peak amplitude of vertical translation was ~1.5 cm and amplitude of pitch rotation was ~3°. Amplitudes of lateral translation and roll rotation were ~1 cm and 1.5–3°, respectively. Overall, cats' heads were neutral in roll and 10–30° nose-down, maintaining horizontal semicircular canals and utriculi within 10° of the earth horizontal. The head longitudinal velocity was 0.5–1 m/s, maximal upward and downward linear velocities were ~0.05 and ~0.1 m/s, respectively, and maximal lateral velocity was ~0.05 m/s. Maximal velocities of head pitch rotation were 20–50 °/s. During walking in light, cats stood 0.3–0.5 cm taller and held their head 0.5–2 cm higher than in darkness. Forward acceleration was 25–100% higher and peak-to-peak amplitude of head pitch oscillations was ~20 °/s larger. We concluded that, during walking, the head of the cat is held actively. Reflexes appear to play only a partial role in determining head movement, and vision might further diminish their role. PMID:27339731

Passive Cushiony Biomechanics of Head Protection in Falling Geckos

OpenAIRE

Wang, Hao; Wang, Wenbo; Song, Yi; Cai, Lei; Dai, Zhendong

2018-01-01

Gekko geckos are capable to crawl on the steep even on upside-down surfaces. Such movement, especially at great altitude, puts them at high risks of incidentally dropping down and inevitable body or head impactions, though they may trigger air-righting reaction (ARR) to attenuate the landing shocks. However, the air-righting ability (ARA) in Gekko geckos is not fully developed. The implementation of ARR in some geckos is quite slow; and for those without tails, the ARR is even unobservable. S...

Consideration about the contamination decreasing method of a crystalline lens in head CT

International Nuclear Information System (INIS)

Yamazaki, Shoichi; Matsueda, Katsuhiro; Matsumura, Mitsumi

2002-01-01

It is effective as a method for reducing the dose of a crystalline lens when enforcing Head CT to change the height of a bed, or it inquired. As a result of measuring, the dose of a crystalline lens became a low value sharply, when the quantity of a bed was moved to the up position. When a problem does not arise in diagnosis, the dose of a crystalline lens can be decreased by inspecting in the upper part as much as possible. As a method of reducing the dose of a crystalline lens, it is very useful. (author)

Understanding the Effects of Long-duration Space Flight on Astronant Functional Task Performance

Science.gov (United States)

Bloomberg, Jacob J.; Batson, Crystal D.; Buxton, Roxanne E.; Feiveson, Al H.; Kofman, Igor S.; Lee, Stuart M. C.; Miller, Chris A.; Mulavara, Ajitkumar P.; Peters, Brian T.; Phillips, Tiffany;

Effect of head size on 10B dose distribution

International Nuclear Information System (INIS)

Gupta, N.; Blue, T.E.; Gahbauer, R.

1992-01-01

Boron neutron capture therapy (BNCT) for treatment of brain tumors is based on the utilization of large epithermal-neutron fields. Epithermal neutrons thermalize at depths of ∼2.5 cm inside the head and provide a maximum thermal fluence at deep-seated tumor sites with minimum damage to normal tissue. Brain tissue is a highly scattering medium for epithermal and thermal neutrons; therefore, a broad treatment field enables epithermal neutrons to enter the head over a large area. These neutrons slow down as they undergo scattering collisions and contribute to the thermal-neutron fluence at the tumor location. With the use of large neutron fields, the size of the head affects the thermal-neutron distribution and thereby the 10 B absorbed dose distribution inside the head. In this paper, the authors describe measurements using a boron trifluoride (BF 3 )-filled proportional counter to determine the effect of head size on 10 B absorbed dose distributions for a broad field accelerator epithermal-neutron source

Experimental Determination of Bed Conditions in Concentrated Pyroclastic Density Currents

Science.gov (United States)

Winner, A.; Ferrier, K.; Dufek, J.

2016-12-01

Pyroclastic density currents (PDCs) are ground-hugging mixtures of hot gas and rock that can reach temperatures > 800 oC and speeds of 200 m/s. These flows are capable of eroding and entraining the underlying bed material into the flow, which can strongly influence flow momentum, runout distance, and hazards associated with PDCs. However, the mechanism of erosion remains poorly constrained, with proposed mechanisms including under-pressure following the head of the fluidized current, force chain enhanced stresses at the bed, and discrete particle impacts and friction. The interactions between PDCs and the bed have been difficult to observe in the field, as their infrequent occurrence, opacity, and hostile environment make real-time measurement difficult. This study is aimed at obtaining a better understanding of the interactions between PDCs and the bed through a quantitative analysis of bed forces. Our experimental apparatus consists of a rotating cylindrical flume of radius 22 cm, within which gas-rich granular material flows along the interior of the cylinder as it rotates. By using a rotating cylinder, we are able to simulate long-duration flows, allowing us to observe impact forces at the bed over timescales comparable to the flow duration of natural PDCs. To measure the distribution and evolution of forces imparted by the flow on the bed, we constructed a cylindrical insert with a non-erodible bed in which we embedded force sensor arrays parallel and perpendicular to the direction of flow. To measure the forces felt by the particles in the flow, we added "smart particles" 25 to 50 mm in diameter to the flow. Each smart particle contains a three-axis accelerometer and a micro SD card enclosed in a spherical plastic casing, and possesses a density similar to that of the pumice in the experimental flow. Each smart particle also contains a three-axis magnetometer which permits its location to be tracked by means of a unique applied magnetic field. Ultimately

Heatup of the TMI-2 lower head during core relocation

International Nuclear Information System (INIS)

Wang, S.K.; Sienicki, J.J.; Spencer, B.W.

1989-01-01

An analysis has been carried out to assess the potential of a melting attack upon the reactor vessel lower head and incore instrument nozzle penetration weldments during the TMI core relocation event at 224 minutes. Calculations were performed to determine the potential for molten corium to undergo breakup into droplets which freeze and form a debris bed versus impinging upon the lower head as one or more coherent streams. The effects of thermal-hydraulic interactions between corium streams and water inside the lower plenum, the effects of the core support assembly structure upon the corium, and the consequences of corium relocation by way of the core former region were examined. 19 refs., 24 figs

Efficacy of an Essential Oil-Based Pesticide for Controlling Bed Bug (Cimex lectularius Infestations in Apartment Buildings

Directory of Open Access Journals (Sweden)

Changlu Wang

2014-11-01

Full Text Available Bed bugs (Cimex lectularius L. and Cimex hemipterus F. are among the most difficult urban pests to manage. Many essential oil-based bed bug control products that are considered reduced risk to mammals compared to synthetic insect neurotoxins have become commercially available, but their effectiveness as a stand-alone control method is unknown. This study assessed the field efficacy of an essential oil-based bed bug control product (EcoRaider; a.i. 1% geraniol + 1% cedar oil + 2% sodium lauryl sulfate compared to a pyrethroid and neonicotinoid mixture spray (0.075% Temprid SC; a.i. beta-cyfluthrin + imidacloprid. After 12 weeks, the three treatments—EcoRaider, Temprid SC, and EcoRaider + Temprid SC caused 92.5 ± 2.7, 92.9 ± 3.0, and 91.7% ± 2.7% bed bug count reduction, respectively. No significant differences existed in the bed bug reduction among the treatments. Bed bugs were eliminated from only 22% of the treated apartments. Among those still with bed bugs, 76% of the residents did not know bed bugs were present. We documented the residents’ self-control practices and discussed the potential of using essential oil-based insecticides in bed bug management programs to minimize the health risks to building occupants and pets and to slow down the development of insecticide resistance.

Renal and sympathoadrenal responses in space

DEFF Research Database (Denmark)

Christensen, N J; Drummer, C; Norsk, P

2001-01-01

According to a classic hypothesis, weightlessness should promote the renal excretion rate of sodium and water and lead to a fluid- and electrolyte-depleted state. This hypothesis is based on experiments in which weightlessness has been simulated in humans by head-down bed rest and water immersion...

Experiments on Pool-riffle Sequences with Multi-fractional Sediment Bed During Floods

Science.gov (United States)

Rodriguez, J. F.; Vahidi, E.; Bayat, E.; de Almeida, G. A. M.; Saco, P. M.

2017-12-01

The morphodynamics of pools and riffles has been the subject of research for over a century and has more recently attracted intense attention for their central role in providing habitat diversity conditions, both in terms of flow and substrate. Initial efforts to explain the long-term stability of the pool-riffle (PR) sequences (often referred to as self-maintenance) focused almost exclusively on cross sectional flow characteristics (either average or near bed velocity or shear stress), using episodic shifts in higher shear stress or velocities from riffles to pools during floods (i.e. reversal conditions) as an indication of the long-term self-maintenance of the structures.. However, less attention has been paid to the interactions of flow unsteadiness, sediment supply and sedimentological contrasts as the drivers for maintaining PR sequences. Here we investigate these effects through laboratory experiments on a scaled-down PR sequence of an existing gravel bed river. Froude similitude and equality of Shields' number were applied to scale one- to four-year recurrence flood events and sediment size distributions, respectively. We conducted experiments with different hydrographs and different sedimentological conditions. In each experiment we continuously measured velocities and shear stresses (using acoustic velocity profilers) bed levels (using a bed profiler) and bed grain size distribution (using an automatic digital technique on the painted bed sediments) during the hydrographs. Our results show that the most important factors for self-maintenance were the sediment bed composition, the level of infilling of the pool and the sediment supply grainsize distribution. These results highlight the need to consider the time varying sedimentological characteristics of a PR sequence to assess its capacity for self-maintenance.

7 CFR 2902.15 - Bedding, bed linens, and towels.

Science.gov (United States)

2010-01-01

... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that... minimum biobased content is 12 percent and shall be based on the amount of qualifying biobased carbon in..., and silk are not qualifying biobased feedstocks for the purpose of determining the biobased content of...

Evaluation of a clay-based acidic bedding conditioner for dairy cattle bedding.

Science.gov (United States)

Proietto, R L; Hinckley, L S; Fox, L K; Andrew, S M

2013-02-01

This study investigated the effects of a clay-based acidic bedding conditioner on sawdust bedding pH, dry matter (DM), environmental pathogen counts, and environmental bacterial counts on teat ends of lactating dairy cows. Sixteen lactating Holstein cows were paired based on parity, days in milk, milk yield, and milk somatic cell count, and were negative for the presence of an intramammary pathogen. Within each pair, cows were randomly assigned to 1 of 2 treatments with 3-wk periods in a crossover design. Treatment groups consisted of 9 freestalls per group bedded with either untreated sawdust or sawdust with a clay-based acidic bedding conditioner, added at 3- to 4-d intervals over each 21-d period. Bedding and teat ends were aseptically sampled on d 0, 1, 2, 7, 14, and 21 for determination of environmental bacterial counts. At the same time points, bedding was sampled for DM and pH determination. The bacteria identified in the bedding material were total gram-negative bacteria, Streptococcus spp., and coliform bacteria. The bacteria identified on the teat ends were Streptococcus spp., coliform bacteria, and Klebsiella spp. Teat end score, milk somatic cell count, and intramammary pathogen presence were measured weekly. Bedding and teat cleanliness, environmental high and low temperatures, and dew point data were collected daily. The bedding conditioner reduced the pH, but not the DM, of the sawdust bedding compared with untreated sawdust. Overall environmental bacterial counts in bedding were lower for treated sawdust. Total bacterial counts in bedding and on teat ends increased with time over both periods. Compared with untreated sawdust, the treated bedding had lower counts of total gram-negative bacteria and streptococci, but not coliform counts. Teat end bacterial counts were lower for cows bedded on treated sawdust for streptococci, coliforms, and Klebsiella spp. compared with cows bedded on untreated sawdust. The clay-based acidic bedding conditioner

Radiostereometric analysis comparison of wear of highly cross-linked polyethylene against 36- vs 28-mm femoral heads.

Science.gov (United States)

Bragdon, Charles R; Greene, Meridith E; Freiberg, Andrew A; Harris, William H; Malchau, Henrik

2007-09-01

This study used radiostereometric analysis (RSA) to compare the femoral head penetration of 28- vs 36-mm-diameter femoral heads into highly cross-linked polyethylene in 2 groups of total hip arthroplasty patients. Thirty patients were enrolled in this RSA study using highly cross-linked polyethylene (Longevity, Zimmer Inc, Warsaw, Idaho) against either 28- or 36-mm-diameter cobalt chrome femoral heads. At 3-year follow-up, there was no significant difference in the total average femoral head penetration, including both creep and wear, using 3 methods of RSA measurement between the 2 groups. Importantly, after bedding-in, there was no further significant increase in the amount of femoral head penetration (ie, wear) with either head size between years 1 and 3. There were no radiographic signs of lysis or radiolucencies at a minimum 3-year follow-up.

High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study.

Science.gov (United States)

Kramer, Andreas; Kümmel, Jakob; Mulder, Edwin; Gollhofer, Albert; Frings-Meuthen, Petra; Gruber, Markus

2017-01-01

Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance. 23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12) or the control group (CTRL, n = 11). A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5-6 sessions per week. Peak force for the reactive hops (3.6±0.4 kN) as well as jump height (35±4 cm) and peak power (3.1±0.2 kW) for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03). Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect pjump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.

Indomethacin induced avascular necrosis of head of femur

Science.gov (United States)

Prathapkumar, K; Smith, I; Attara, G

2000-01-01

Chemically induced avascular necrosis of bone is a well documented entity. Indomethacin is one of the causes of this condition but is often difficult to recognise. Review of the literature shows that only one case of indomethacin induced avascular necrosis has been reported in the English language between 1966 and the present.
The case of a young healthy man, who developed avascular necrosis of head of femur after prolonged administration of indomethacin, is reported here.


Keywords: indomethacin; avascular necrosis PMID:10964124

Orienting of attention via observed eye gaze is head-centred.

Science.gov (United States)

Bayliss, Andrew P; di Pellegrino, Giuseppe; Tipper, Steven P

2004-11-01

Observing averted eye gaze results in the automatic allocation of attention to the gazed-at location. The role of the orientation of the face that produces the gaze cue was investigated. The eyes in the face could look left or right in a head-centred frame, but the face itself could be oriented 90 degrees clockwise or anticlockwise such that the eyes were gazing up or down. Significant cueing effects to targets presented to the left or right of the screen were found in these head orientation conditions. This suggests that attention was directed to the side to which the eyes would have been looking towards, had the face been presented upright. This finding provides evidence that head orientation can affect gaze following, even when the head orientation alone is not a social cue. It also shows that the mechanism responsible for the allocation of attention following a gaze cue can be influenced by intrinsic object-based (i.e. head-centred) properties of the task-irrelevant cue.

Combination of granular activated carbon adsorption and deep-bed filtration as a single advanced wastewater treatment step for organic micropollutant and phosphorus removal.

Science.gov (United States)

Altmann, Johannes; Rehfeld, Daniel; Träder, Kai; Sperlich, Alexander; Jekel, Martin

2016-04-01

Adsorption onto granular activated carbon (GAC) is an established technology in water and advanced wastewater treatment for the removal of organic substances from the liquid phase. Besides adsorption, the removal of particulate matter by filtration and biodegradation of organic substances in GAC contactors has frequently been reported. The application of GAC as both adsorbent for organic micropollutant (OMP) removal and filter medium for solids retention in tertiary wastewater filtration represents an energy- and space saving option, but has rarely been considered because high dissolved organic carbon (DOC) and suspended solids concentrations in the influent of the GAC adsorber put a significant burden on this integrated treatment step and might result in frequent backwashing and unsatisfactory filtration efficiency. This pilot-scale study investigates the combination of GAC adsorption and deep-bed filtration with coagulation as a single advanced treatment step for simultaneous removal of OMPs and phosphorus from secondary effluent. GAC was assessed as upper filter layer in dual-media downflow filtration and as mono-media upflow filter with regard to filtration performance and OMP removal. Both filtration concepts effectively removed suspended solids and phosphorus, achieving effluent concentrations of 0.1 mg/L TP and 1 mg/L TSS, respectively. Analysis of grain size distribution and head loss within the filter bed showed that considerable head loss occurred in the topmost filter layer in downflow filtration, indicating that most particles do not penetrate deeply into the filter bed. Upflow filtration exhibited substantially lower head loss and effective utilization of the whole filter bed. Well-adsorbing OMPs (e.g. benzotriazole, carbamazepine) were removed by >80% up to throughputs of 8000-10,000 bed volumes (BV), whereas weakly to medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) showed removals activated carbon (PAC) to deep-bed filtration as a direct

Clipping of tumour resection margins allows accurate target volume delineation in head and neck cancer adjuvant radiation therapy

International Nuclear Information System (INIS)

Bittermann, Gido; Wiedenmann, Nicole; Bunea, Andrei; Schwarz, Steffen J.; Grosu, Anca-L.; Schmelzeisen, Rainer; Metzger, Marc C.

2015-01-01

Background: Accurate tumour bed localisation is a key requirement for adjuvant radiotherapy. A new procedure is described for head and neck cancer treatment that improves tumour bed localisation using titanium clips. Materials and methods: Following complete local excision of the primary tumour, the tumour bed was marked with titanium clips. Preoperative gross target volume (GTV) and postoperative tumour bed were examined and the distances between the centres of gravity were evaluated. Results: 49 patients with squamous cell carcinoma of the oral cavity were prospectively enrolled in this study. All patients underwent tumour resection, neck lymph node dissection and defect reconstruction in one stage. During surgery, 7–49 clips were placed in the resection cavity. Surgical clip insertion was successful in 88% (n = 43). Clip identification and tumour bed delineation was successful in all 43 patients. The overall distance between the centres of gravity of the preoperative tumour extension to the tumour bed was 0.9 cm. A significant relationship between the preoperative tumour extension and the postoperative tumour bed volume could be demonstrated. Conclusion: We demonstrate a precise delineation of the former tumour cavity. Improvements in tumour bed delineation allow an increase of accuracy for adjuvant treatment

Isolated abducens nerve palsy after closed head trauma: a pediatric case report.

Science.gov (United States)

Janssen, Karen; Wojciechowski, Marek; Poot, Sandra; De Keyser, Katrien; Ceulemans, Berten

2008-09-01

Cranial nerve lessions often accompany head trauma. Nevertheless, isolated involvement of the sixth nerve without any cranial or cervical fracture is rare. Nerve injury could occur at the sites of the dural entry points and at the petrous apex during down- or upward movement of the brain caused by violent linear force to the head. Management is symptomatic. Most cases improve within three months and many resolve by six months, but spontaneous recovery does not always occur. We describe the case of a 13-year-old boy who developed isolated abducens nerve palsy after closed head trauma.

Prolonged radiation time and low nadir hemoglobin during postoperative concurrent chemoradiotherapy are both poor prognostic factors with synergistic effect on locally advanced head and neck cancer patients

Directory of Open Access Journals (Sweden)

Su NW

2015-01-01

Full Text Available Nai-Wen Su,1 Chung-Ji Liu,2 Yi-Shing Leu,3 Jehn-Chuan Lee,3 Yu-Jen Chen,4 Yi-Fang Chang1,51Division of Medical Oncology and Hematology, Department of Internal Medicine, 2Department of Oral and Maxillofacial Surgery, 3Department of Otorhinolaryngology, 4Department of Radiation Oncology, 5Good Clinical Research Center, Department of Medical Research, Mackay Memorial Hospital, Taipei, TaiwanBackground: Anemia, a common complication of head and neck cancer treatment, is regarded as a poor prognostic factor. We evaluated the impact of low hemoglobin (Hb levels, measured at different time points, on a consecutive cohort of patients with locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN who underwent postoperative concurrent chemoradiotherapy (CCRT.Materials and methods: From 2002 to 2009, 140 patients were enrolled and reviewed retrospectively. Preoperative (pre-op Hb, pre-CCRT Hb, and nadir Hb during CCRT were measured and recorded. The three Hb parameters were analyzed against several well-established pathologic risk factors and radiation-associated variables. Prognostic impacts were investigated with multivariate analysis by Cox proportional hazards model.Results: On Cox regression analysis, significantly higher risk of death was associated with pre-op Hb %13 g/dL (hazard ratio [HR] =1.8; 95% confidence interval [CI], 1.1–3.1; P=0.023, nadir Hb %11 g/dL (HR =1.9; 95% CI, 1.1–3.3; P=0.020, radiation treatment time (RTT >7 weeks (HR =1.9; 95% CI, 1.1–3.3; P=0.022, and multiple positive lymph nodes (HR =2.1; 95% CI, 1.2–3.7; P=0.010, after adjusting for primary tumor site and pathologic lymphovascular invasion. Patients with poor prognosticators including low nadir Hb %11 g/dL and RTT >7 weeks had a higher risk of death (HR =4.0; 95% CI =1.6–10.2; P=0.004.Conclusion: In the treatment setting of LA-SCCHN patients who underwent postoperative CCRT, coexistance of lower nadir Hb during CCRT and prolonged RTT resulted in

Triiodothyronine increases calcium loss in a bed rest antigravity model for space flight.

Science.gov (United States)

Smith, Steven R; Lovejoy, Jennifer C; Bray, George A; Rood, Jennifer; Most, Marlene M; Ryan, Donna H

2008-12-01

Bed rest has been used as a model to simulate the effects of space flight on bone metabolism. Thyroid hormones accelerate bone metabolism. Thus, supraphysiologic doses of this hormone might be used as a model to accelerate bone metabolism during bed rest and potentially simulate space flight. The objective of the study was to quantitate the changes in bone turnover after low doses of triiodothyronine (T(3)) added to short-term bed rest. Nine men and 5 women were restricted to bed rest for 28 days with their heads positioned 6 degrees below their feet. Subjects were randomly assigned to receive either placebo or oral T(3) at doses of 50 to 75 microg/d in a single-blind fashion. Calcium balance was measured over 5-day periods; and T(3), thyroxine, thyroid-stimulating hormone, immunoreactive parathyroid hormone, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline were measured weekly. Triiodothyronine increased 2-fold in the men and 5-fold in the women during treatment, suppressing both thyroxine and thyroid-stimulating hormone. Calcium balance was negative by 300 to 400 mg/d in the T(3)-treated volunteers, primarily because of the increased fecal loss that was not present in the placebo group. Urinary deoxypyridinoline to creatinine ratio, a marker of bone resorption, increased 60% in the placebo group during bed rest, but more than doubled in the T(3)-treated subjects (P < .01), suggesting that bone resorption was enhanced by treatment with T(3). Changes in serum osteocalcin and bone-specific alkaline phosphatase, markers of bone formation, were similar in T(3)- and placebo-treated subjects. Triiodothyronine increases bone resorption and fecal calcium loss in subjects at bed rest.

Thermal hydraulic and neutronic interaction in the rotating bed reactor

International Nuclear Information System (INIS)

Lee, C.C.

1986-01-01

Power transient characteristics in a rotating fluidized bed reactor (RBR) are investigated theoretically. A propellant flow perturbation is assumed to occur in an initially equilibrium state of the core. Transfer functions representing quasi-one-dimensional mutual feedback between thermal hydraulics and neutronics are developed and analyzed in the frequency domain. Neutronic responses are determined by Fermi-age theory for slowing down of fast neutrons and diffusion theory for thermal neutron distribution. Neutron leakage through the exhaust nozzle is accounted for by applying diffuse view factors similar to those applied in radiative heat transfer. The bed expansion behavior is described by a kinematic wave equation derived from the continuity of the gas phase. The drift flux approach is used to determine the yield fractions in the equilibrium bed. Thermal responses of fuel are evaluated by dividing it into several volume-averaged zones to better account for the transient effects over single zone models. Sample calculations are undertaken for the various operation conditions and design parameters of the RBR based on 250 MW/sub t/, 1000 MW/sub t/, and 5000 MW/sub t/ power reactors. The results show that power transients are dependent on the parametric changes of optical thickness and view factors

Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation.

LENUS (Irish Health Repository)

Ni Ainle, Fionnuala

2009-08-20

Protamine sulfate is a positively charged polypeptide widely used to reverse heparin-induced anticoagulation. Paradoxically, prospective randomized trials have shown that protamine administration for heparin neutralization is associated with increased bleeding, particularly after cardiothoracic surgery with cardiopulmonary bypass. The molecular mechanism(s) through which protamine mediates this anticoagulant effect has not been defined. In vivo administration of pharmacologic doses of protamine to BALB\\/c mice significantly reduced plasma thrombin generation and prolonged tail-bleeding time (from 120 to 199 seconds). Similarly, in pooled normal human plasma, protamine caused significant dose-dependent prolongations of both prothrombin time and activated partial thromboplastin time. Protamine also markedly attenuated tissue factor-initiated thrombin generation in human plasma, causing a significant decrease in endogenous thrombin potential (41% +\\/- 7%). As expected, low-dose protamine effectively reversed the anticoagulant activity of unfractionated heparin in plasma. However, elevated protamine concentrations were associated with progressive dose-dependent reduction in thrombin generation. To assess the mechanism by which protamine mediates down-regulation of thrombin generation, the effect of protamine on factor V activation was assessed. Protamine was found to significantly reduce the rate of factor V activation by both thrombin and factor Xa. Protamine mediates its anticoagulant activity in plasma by down-regulation of thrombin generation via a novel mechanism, specifically inhibition of factor V activation.

Multiple bony lesions other than femoral heads on 99mTc-MDP bone scan in patients with avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Choi, Yun Young; Yang, Seoung Oh; Moon, Dae Hyuk; Ryu, Jin Sook; Weon, Young Cheol; Shin, Myung Jin; Lee, Soo Ho; Lee, Hee Kyung; Chun, Hae Kyung

1997-01-01

To evaluate the clinical significance of the multiple increased uptake lesions other than in femoral heads as seen on whole body bone scan in patients with avascular necrosis of femoral heads. One hundred and seventy three patients with clinical diagnosis of avascular necrosis of the emoral head underwent a bone scan using Tc-99m MDP. Increased uptake lesions other than in femoral heads were evaluated, including frequency and common sites of in volvement, and correlated with clinical information and plain radiographic findings. Two hundred patients without AVN, who had undergone a bone scan, were included as a control group. Increased uptake lesions in extrafemoral head locations were found in 36 of 173 patients(20.8%;the location of 79 lesions was other than the femoral head, This result is statistically different from patients without avascular necrosis of femoral head(p<0.0001). The most common site of involvement was the knee joint area(62.5%). Other lesions were located in the mid-shafts of the long bones of the lower extremities, calcaneus, proximal humerus, etc., in order of decreasing frequency. Plain radiographs of 17 lesions were nonspecific, except for three lesions showing definite changes associated with avascular necrosis. The risk factors included alcoholism, the prolonged use of steroids, renal transplantation, herbal medication and working as a working as deep-sea diver. Most patients did not complain of pain, except for two with irreversible osteonecrotic changes as seen on plain radiograph. in patients with avascular necrosis of the femur, increased uptake lesions other than in the femoral head as seen on bone scan, may represent the early stage of osteonecrosis, which shows a characteristic appearance on bone scan. In order to aveid possible misdiagnoses of multiple extrafemoral lesions as bony metastasis or traumatic lesions, in patients with avascular necrosis of the femur these should be carefully evaluated

Lhermitte's Sign Developing after IMRT for Head and Neck Cancer

Directory of Open Access Journals (Sweden)

Dong C. Lim

2010-01-01

Full Text Available Background. Lhermitte's sign (LS is a benign form of myelopathy with neck flexion producing an unpleasant electric-shock sensation radiating down the extremities. Although rare, it can occur after head and neck radiotherapy. Results. We report a case of Lhermitte's developing after curative intensity-modulated radiotherapy (IMRT for a patient with locoregionally advanced oropharyngeal cancer. IMRT delivers a conformal dose of radiation in head and neck cancer resulting in a gradient of radiation dose throughout the spinal cord. Using IMRT, more dose is delivered to the anterior spinal cord than the posterior cord. Conclusions. Lhermitte's sign can develop after IMRT for head and neck cancer. We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.

High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study.

Directory of Open Access Journals (Sweden)

Andreas Kramer

Full Text Available Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance.23 male participants (29±6 years, 181±6 cm, 77±7 kg were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT, and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12 or the control group (CTRL, n = 11. A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5-6 sessions per week.Peak force for the reactive hops (3.6±0.4 kN as well as jump height (35±4 cm and peak power (3.1±0.2 kW for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03. Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect p<0.001.Participants tolerated the near-daily high-intensity jump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.

Road Tripping down the Digital Preservation Highway, Part I: Hitting the Road

Science.gov (United States)

Colati, Jessica Branco; Colati, Gregory C.

2011-01-01

In this inaugural column, the authors introduce Peter Palmer, erstwhile librarian at Bellaluna University who is being tasked with managing the library's and university's digital content as he begins his journey down the Digital Highway. As head of access services at Bellaluna University, Peter had been, by default, made responsible for managing…

Hydrogeochemistry and coal-associated bacterial populations from a methanogenic coal bed

Science.gov (United States)

Barnhart, Elliott P.; Weeks, Edwin P.; Jones, Elizabeth J.P.; Ritter, Daniel J.; McIntosh, Jennifer C.; Clark, Arthur C.; Ruppert, Leslie F.; Cunningham, Alfred B.; Vinson, David S.; Orem, William H.; Fields, Matthew W.

2016-01-01

Biogenic coalbed methane (CBM), a microbially-generated source of natural gas trapped within coal beds, is an important energy resource in many countries. Specific bacterial populations and enzymes involved in coal degradation, the potential rate-limiting step of CBM formation, are relatively unknown. The U.S. Geological Survey (USGS) has established a field site, (Birney test site), in an undeveloped area of the Powder River Basin (PRB), with four wells completed in the Flowers-Goodale coal bed, one in the overlying sandstone formation, and four in overlying and underlying coal beds (Knoblach, Nance, and Terret). The nine wells were positioned to characterize the hydraulic conductivity of the Flowers-Goodale coal bed and were selectively cored to investigate the hydrogeochemistry and microbiology associated with CBM production at the Birney test site. Aquifer-test results indicated the Flowers-Goodale coal bed, in a zone from about 112 to 120 m below land surface at the test site, had very low hydraulic conductivity (0.005 m/d) compared to other PRB coal beds examined. Consistent with microbial methanogenesis, groundwater in the coal bed and overlying sandstone contain dissolved methane (46 mg/L average) with low δ13C values (−67‰ average), high alkalinity values (22 meq/kg average), relatively positive δ13C-DIC values (4‰ average), and no detectable higher chain hydrocarbons, NO3−, or SO42−. Bioassay methane production was greatest at the upper interface of the Flowers-Goodale coal bed near the overlying sandstone. Pyrotag analysis identified Aeribacillus as a dominant in situbacterial community member in the coal near the sandstone and statistical analysis indicated Actinobacteria predominated coal core samples compared to claystone or sandstone cores. These bacteria, which previously have been correlated with hydrocarbon-containing environments such as oil reservoirs, have demonstrated the ability to produce biosurfactants to break down

Impacts of artificial inundation of ephemeral creek beds on mature riparian eucalypts in semi-arid northwest Australia

Science.gov (United States)

Argus, Rachel; Page, Gerald; Grierson, Pauline

2014-05-01

The resilience of riparian ecosystems of intermittent rivers to changes in their hydrological regimes is not well understood. In the Pilbara region of northwest Australia, streams flow only occasionally, reflecting a highly dynamic and extremely variable cycle of prolonged droughts punctuated by occasional floods. However, discharge of ground water pumped from mining activities over recent years has resulted in localised areas with constant surface water. Here we sought to assess impacts of prolonged saturation on the health and functioning of two co-occurring eucalypts (Eucalyptus camaldulensis and Eucalyptus victrix). While riparian vegetation is clearly adapted to partial root-zone hypoxia, we hypothesised that trees in inundated areas experience reduced root function due to an energy crisis, which will be reflected by symptoms in the foliage. We expected that complete saturation of the entire root system for an extended time period reduces physiological function through lower stomatal conductance and more negative water potential, results in canopy sparseness and reduces accumulation of foliar nitrogen and phosphorus. Trees (n=26) were assessed at two sites with artificially permanent surface water (discharge sites) and compared to trees (n=21) at a site with a naturally occurring permanent groundwater fed pool ('reference site'). Trees were sampled from a range of positions including the stream bed, the lower bank and the upper bank, in order to determine the extent of influence of the discharge water. No eucalypts grew in the stream bed at the reference site, indicating either the stream bed conditions were unsuitable for seedling survival or eucalypts were outcompeted by the flood tolerant tree Melaleuca argentea (which was absent from the impact sites). Soil redox potential, an indicator of oxygen availability and other soil chemical conditions, was measured with platinum redox probes at 25 cm depth. Trees were assessed for canopy cover, foliage water

Management bedding : vrijloopstal met composterende bedding van houtsnippers

NARCIS (Netherlands)

Boer, de H.C.; Wiersma, M.; Galama, P.J.; Szanto, G.L.

2015-01-01

In de vrijloopstal liggen de koeien meestal op een organische bedding en scheiden daar mest (feces en urine) uit. Om de bedding voldoende droog en schoon te houden wordt er regelmatig nieuw strooisel aangevoerd en wordt de toplaag bewerkt. Op basis van onderzoek- en praktijkervaringen tot nu toe

Incidence and Risk Factors for Prolonged Hospitalization and Readmission after Transsphenoidal Pituitary Surgery.

Science.gov (United States)

Bur, Andrés M; Brant, Jason A; Newman, Jason G; Hatten, Kyle M; Cannady, Steven B; Fischer, John P; Lee, John Y K; Adappa, Nithin D

2016-10-01

To evaluate the incidence and factors associated with 30-day readmission and to analyze risk factors for prolonged hospital length of stay following transsphenoidal pituitary surgery. Retrospective longitudinal claims analysis. American College of Surgeons National Surgical Quality Improvement Program. The database of the American College of Surgeons National Surgical Quality Improvement Program was queried for patients who underwent transsphenoidal pituitary surgery (Current Procedural Terminology code 61548 or 62165) between 2005 and 2014. Patient demographic information, indications for surgery, and incidence of hospital readmission and length of stay were reviewed. Risk factors for readmission and prolonged length of stay, defined as >75th percentile for the cohort, were identified through logistic regression modeling. A total of 1006 patients were included for analysis. Mean hospital length of stay after surgery was 4.1 ± 0.2 days. Predictors of prolonged length of stay were operative time (P surgery between 2012 and 2014, 7.2% (n = 38) required hospital readmission. History of congestive heart failure (CHF) was a predictor of hospital readmission (P = 0.03, OR = 12.7, 95% CI = 1.1-144.0). This review of a large validated surgical database demonstrates that CHF is an independent predictor of hospital readmission after transsphenoidal surgery. Although CHF is a known risk factor for postoperative complications, it poses unique challenges to patients with potential postoperative pituitary dysfunction. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Ash related bed agglomeration during fluidized bed combustion, further development of the classification method based on CCSEM; CCSEM-luokitusmenetelmaen jatkokehittaeminen tuhkan aiheuttaman agglomeroitumisen tutkimisessa leiju- ja kiertopetipoltossa

Energy Technology Data Exchange (ETDEWEB)

Laitinen, R; Patrikainen, T; Heikkinen, R; Tiainen, M; Virtanen, M [Oulu Univ. (Finland). Inst. of Chemistry

1997-10-01

The scope of this project is to use the information and experience gained from the development of classification method to predict ash related problems like bed agglomeration during fluidised combustion. If boilers have to be shut down due to slagging or agglomeration of the bed material may cause significant economic losses for the entire energy production chain. Mineral classification methods based on the scanning electron microscopy are commonly used for coal ash investigation. In this work different biomass, peat, and peat-wood ash, fluidised-bed materials, and bed agglomerates were analysed with SEM-EDS combined with automatic image analysis software. The properties of ash particles are different depending on the fuel type. If biomass like wood or bark are added to peat the resulting ash has different properties. Due to the low mineral content in the original peat and to the fact that the majority of inorganic material is bound to the organic matrix, the classification has turned out to be less informative than was hoped. However, good results are obtained the by use of quasiternary diagrams. With these diagrams the distribution of particle composition is easily illustrated and thus meaningful prediction can be made of the slagging and agglomerating properties of ash. The content of ten different elements are determined for each particle by SEM-EDS combined with Link AIA software. The composition of the diagram corners can be varied Freely within these ten elements. (orig.)

Effect of bed particles to combustion of gases in fluidized bed

Energy Technology Data Exchange (ETDEWEB)

Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

1997-10-01

The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

Multiple bony lesions other than femoral heads on {sup 99m}Tc-MDP bone scan in patients with avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Choi, Yun Young; Yang, Seoung Oh; Moon, Dae Hyuk; Ryu, Jin Sook; Weon, Young Cheol; Shin, Myung Jin; Lee, Soo Ho; Lee, Hee Kyung [Asan Medical Center, Ulsan Univ. College of Medicine, Ulsan (Korea, Republic of); Chun, Hae Kyung [St. Francisco Hospital, Seoul (Korea, Republic of)

1997-03-01

To evaluate the clinical significance of the multiple increased uptake lesions other than in femoral heads as seen on whole body bone scan in patients with avascular necrosis of femoral heads. One hundred and seventy three patients with clinical diagnosis of avascular necrosis of the emoral head underwent a bone scan using Tc-99m MDP. Increased uptake lesions other than in femoral heads were evaluated, including frequency and common sites of in volvement, and correlated with clinical information and plain radiographic findings. Two hundred patients without AVN, who had undergone a bone scan, were included as a control group. Increased uptake lesions in extrafemoral head locations were found in 36 of 173 patients(20.8%); the location of 79 lesions was other than the femoral head. This result is statistically different from patients without avascular necrosis of femoral head(p<0.0001). The most common site of involvement was the knee joint area(62.5%). Other lesions were located in the mid-shafts of the long bones of the lower extremities, calcaneus, proximal humerus, etc., in order of decreasing frequency. Plain radiographs of 17 lesions were nonspecific, except for three lesions showing definite changes associated with avascular necrosis. The risk factors included alcoholism, the prolonged use of steroids, renal transplantation, herbal medication and working as a working as deep-sea diver. Most patients did not complain of pain, except for two with irreversible osteonecrotic changes as seen on plain radiograph. in patients with avascular necrosis of the femur, increased uptake lesions other than in the femoral head as seen on bone scan, may represent the early stage of osteonecrosis, which shows a characteristic appearance on bone scan. In order to aveid possible misdiagnoses of multiple extrafemoral lesions as bony metastasis or traumatic lesions, in patients with avascular necrosis of the femur these should be carefully evaluated.

Licence prolongations of US nuclear power plants; Les prolongations de licence des centrales nucleaires americaines

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-04-01

Licences of US nuclear reactors were initially attributed for a 40 years duration. However, the vast majority of the reactors can benefit of a licence prolongation for a period of 20 years maximum. This article recalls first the procedure to follow for the licence prolongation demands (safety analysis, components aging, environmental impact statement), and then it makes a status of the accepted prolongations, of the demands under examination, and of the demands that should be presented in the next 5 years. (J.S.)

Stress Tolerance of Bed Bugs: A Review of Factors That Cause Trauma to Cimex lectularius and C. Hemipterus

Directory of Open Access Journals (Sweden)

Joshua B. Benoit

2011-04-01

Full Text Available Recent emergence of bed bugs (Cimex spp. has prompted a significant expansion of research devoted to this pest. The ability to survive and recover from stress has significant implications on the distribution and survival of insects, and bed bugs are no exception. Research on bed bug stress tolerance has shown considerable progress and necessitates a review on this topic. Bed bugs have an extraordinary ability to resist dehydration between bloodmeals, and this represents a critical factor allowing their prolonged survival when no host is available. High relative humidities are detrimental to bed bugs, leading to reduced survival in comparison to those held at lower relative humidities. Continual exposure of bed bugs, eggs and mobile stages, to temperatures below freezing and short term exposure (=1 h to temperatures below −16 to −18 °C results in mortality. The upper thermal limit for short term exposure of eggs, nymphs and adults is between 40–45 °C for the common (Cimex lectularius and tropical (C. hemipterus bed bugs. Long-term exposure to temperatures above 35 °C results in significant reduction in survival of mobile bed bugs. Eggs for C. lectularius and C. hemipterus are no longer viable when held below 10 °C or above 37 °C throughout embryogenesis. Blood feeding, although necessary for survival and reproduction, is discussed as a stress due to thermal and osmotic fluctuations that result from ingesting a warm bloodmeal from a vertebrate host. Cold, heat, water stress and blood feeding prompted the expression of heat shock proteins (Hsps. Pesticide application is a common human-induced stress for urban pests, and recent studies have documented pesticide resistance in many bed bug populations. High levels of traumatic insemination (mating of bed bugs has been linked to reduced survival and fecundity along with possibly exposing individuals to microbial infections after cuticular penetration by the paramere (=male reproductive organ

Validating Experimental Bedform Dynamics on Cohesive Sand-Mud Beds in the Dee Estuary

Science.gov (United States)

Baas, Jaco H.; Baker, Megan; Hope, Julie; Malarkey, Jonathan; Rocha, Renata

2014-05-01

bed was increased. The same result was obtained for xanthan gum, which is a proxy for biological polymers produced by microphytobenthos. Yet, the xanthan gum was several orders more effective in slowing down ripple development than kaolin clay, suggesting that the cohesive forces for biological polymers are much higher than for clay minerals, and that sedimentological process models should refocus on biostabilisation processes. The first results of the field experiments show that the winnowing of fines from developing ripples and the slowing down of current ripple development in mixed cohesive sediment is mimicked on intertidal flats in the Dee estuary. In particular, these field data revealed that current ripples in cohesive sediment are smaller with more two-dimensional crestlines than in non-cohesive sand. The wider implications of these findings will be discussed. COHBED Project Team (NERC): Alan Davies (Bangor University); Daniel Parsons, Leiping Ye (University of Hull); Jeffrey Peakall (University of Leeds); Dougal Lichtman, Louise O'Boyle, Peter Thorne (NOC Liverpool); Sarah Bass, Andrew Manning, Robert Schindler (University of Plymouth); Rebecca Aspden, Emma Defew, Julie Hope, David Paterson (University of St Andrews)

Temporal artery flow response during the last minute of a head up tilt test, in relation with orthostatic intolerance after a 60 day head-down bedrest.

Directory of Open Access Journals (Sweden)

Philippe Arbeille

Full Text Available OBJECTIVE: Check if the Temporal flow response to Tilt could provide early hemodynamic pattern in the minutes preceding a syncope during the Tilt test performed after a 60-d head down bedrest (HDBR. METHOD: Twenty-one men divided into 3 groups [Control (Con, Resistive Vibration (RVE and Chinese Herb (Herb] underwent a 60 day HDBR. Pre and Post HDBR a 20 min Tilt identified Finishers (F and Non Finishers (NF. Cerebral (MCA, Temporal (TEMP, Femoral (FEM flow velocity, were measured by Doppler during the Tilt. Blood pressure (BP was measured by arm cuff and cardiopress. RESULTS AND DISCUSSION: Four of the 21 subjects were NF at the post HDBR Tilt test (Con gr:2, RVE gr: 1, Herb gr: 1. At 1 min and 10 s before end of Tilt in NF gr, FEM flow decreased less and MCA decreased more at post HDBR Tilt compared to pre (p<0.05, while in the F gr they changed similarly as pre. In NF gr: TEMP flow decreased more at post HDBR Tilt compared to pre, but only at 10 s before the end of Tilt (P<0.05. During the last 10 s a negative TEMP diastolic component appeared which induced a drop in mean velocity until Tilt arrest. CONCLUSION: The sudden drop in TEMP flow with onset of a negative diastolic flow preceding the decrease in MCA flow confirm that the TEMP vascular resistance respond more directly than the cerebral one to the cardiac output redistribution and that this response occur several seconds before syncope.

Bed retained products in swept fixed bed (SFB) coal hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Mastral, A.M.; Perez-Surio, M.J. [CSIC, Zaragosa (Spain). Inst. de Carboquimica

1997-12-31

The hydropyrolysis of a low rank coal in a swept fixed bed (SFB) reactor is carried out by fixing the hydrogen pressure (40 kg/cm{sup 2}), the hydrogen flow (2 l/min) and the residence time (10 min) at increasing temperatures (400 C, 500 C and 600 C) and coal bed heights (h, 1.5h, 2h, 2.5h and 3h). It is shown that the percentages of tars and char directly depend on the coal bed height and that there is not only a quantitative dependence, but also the height of the coal bed is very important and plays a relevant role on the nature of the conversion products. (orig.)

In-bed accountability of tritium in production scale metal hydride storage beds

International Nuclear Information System (INIS)

Klein, J.E.

1995-01-01

An ''in-bed accountability'' (IBA) flowing gas calorimetric measurement method has been developed and implemented to eliminate the need to remove tritium from production scale metal hydride storage beds for inventory measurement purposes. Six-point tritium IBA calibration curves have been completed for two, 390 gram tritium metal hydride storage beds. The calibration curves for the two tritium beds are similar to those obtained from the ''cold'' test program. Tritium inventory errors at the 95 percent confidence level ranged from ± 7.3 to 8.6 grams for the cold test results compared to ± 4.2 to 7.5 grams obtained for the two tritium calibrated beds

Prolonged river water pollution due to variable-density flow and solute transport in the riverbed

Science.gov (United States)

Jin, Guangqiu; Tang, Hongwu; Li, Ling; Barry, D. A.

2015-04-01

A laboratory experiment and numerical modeling were used to examine effects of density gradients on hyporheic flow and solute transport under the condition of a solute pulse input to a river with regular bed forms. Relatively low-density gradients due to an initial salt pulse concentration of 1.55 kg m-3 applied in the experiment were found to modulate significantly the pore-water flow and solute transport in the riverbed. Such density gradients increased downward flow and solute transport in the riverbed by factors up to 1.6. This resulted in a 12.2% increase in the total salt transfer from the water column to the riverbed over the salt pulse period. As the solute pulse passed, the effect of the density gradients reversed, slowing down the release of the solute back to the river water by a factor of 3.7. Numerical modeling indicated that these density effects intensified as salt concentrations in the water column increased. Simulations further showed that the density gradients might even lead to unstable flow and result in solute fingers in the bed of large bed forms. The slow release of solute from the bed back to the river led to a long tail of solute concentration in the river water. These findings have implications for assessment of impact of pollution events on river systems, in particular, long-term effects on both the river water and riverbed due to the hyporheic exchange.

Does SIRT-1 Mediate Calorie Restriction and Prolong Life? – A Mini Review

Directory of Open Access Journals (Sweden)

Kordala Anna

2014-09-01

Full Text Available Calorie restriction is the only intervention proved to prolong both average and maximum lifespan in yeast, worms, fish, rodents and possibly primates. Not only does the regimen prolong life, but it also reduces the incident of numerous age-related diseases like diabetes, atherosclerosis or cancer and slows down ageing. Mechanisms by which that is thought to occur have not yet been elucidated, but they probably involve reactive oxygen species signaling, insulin growth factor and transcriptional factors. Here, special emphasis is given to SIRT1 - silent information regulator. There is sound evidence showing that SIRT1 is a key player in mediating physiological response to calorie restriction and that its overexpression is correlated with extended lifespan. The possible mechanism leading to its elevated levels is high NAD/NADH ratio, observed in Sir2 in yeast. SIRT1 increases glucose production, enhances fat mobilization, stimulates angiogenesis, prevents neuronal degeneration and rises insulin sensitivity. Therefore, it seems to be a very beneficial factor activated by such a simple intervention that is calorie restriction.

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

Science.gov (United States)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Down-regulation of dopamine D-2, 5-HT2 receptors and β-adrenoceptors in rat brain after prolonged treatment with a new potential antidepressant, Lu 19-005

International Nuclear Information System (INIS)

Nowak, G.; Arnt, J.; Hyttel, J.; Svendsen, O.

1985-01-01

Lu 19-005 is a new phenylindan derivative with strong and equipotent inhibitory effect on dopamine (DA), noradrenaline (NA) and serotonin (5-HT) uptake. The adaptive effects of 2 weeks treatment with Lu 19-005, on receptor binding in vitro and on d-amphetamine responsiveness in vivo have been investigated in rats. One or 3 days after the final dose the number of β-adrenoceptors and of 5-HT 2 and DA D-2 receptors was decreased by 20-30%, whereas αsub1-adrenoceptor number was slightly decreased only 1 day after withdrawal. The DA D-2 receptor number remained decreased at 7 days withdrawal, but returned to normal after another 3 days. The brain levels of DA, NA and 5-HT were not changed by 2 weeks' Lu 19-005 treatment. The down-regulation of DA D-2 receptors was accompanied by tolerance to d-amphetamine-induced hypermotility (after low doses) and stereotyped licking or biting (after a high dose). The tolerance to d-amphetamine-induced hypermotility was maximal 3-5 days withdrawal time, and remained significant also 15 days after the last dose. The results are discussed in relation to the effect of prolonged treatment with other antidepressant drugs. (Author)

Bed care for patients in palliative settings: considering risks to caregivers and bed surfaces.

Science.gov (United States)

Fragala, Guy

2015-02-01

Ensuring patients are comfortable in bed is key to effective palliative care, but when moving and positioning patients in bed, health professionals face an occupational risk of injury. The turning and positioning (TAP) system is a new method of moving patients in bed, that evidence has shown to reduce the risk of injury to caregivers. Providing the correct bed surface is another aspect of bed care essential to the comfort of the palliative patient, and to aid wound prevention and treatment. It is important to take a patient-centred approach when considering the most appropriate bed surface patients. This article provides an overview and discussion of these two aspects of bed care for palliative patients.

Quality of drug label information on QT interval prolongation

DEFF Research Database (Denmark)

Warnier, Miriam J; Holtkamp, Frank A; Rutten, Frans H

2014-01-01

BACKGROUND: Information regarding QT-prolongation in the drug label may vary between products. This could lead to suboptimal risk minimization strategies. OBJECTIVE: To systematically assess the variation in the extent and content of information on QT prolongation in the summary of product......-prolongation'/'QT-prolongation') and the advice on cautionary measures pertaining to QT-prolongation in the label were examined, as well as their association. RESULTS: Of the 175 screened products, 44 contained information on QT in the SPC ('no QT-prolongation': 23%, 'unclear drug-QT association': 43%, 'possibly QT-prolongation': 16%, 'QT......-prolongation': 18%). 62% contained advices to act with caution in patients with additional risk factors for QT-prolongation. Products that more likely to have QT-prolonging properties according to the SPC provided more information on QT-prolongation in the SPC ('no prolongation': 10% and for the category 'QT...

Fluid bed porosity equation for an inverse fluidized bed bioreactor with particles growing biofilm

International Nuclear Information System (INIS)

Campos-Diaz, K. E.; Limas-Ballesteros, R.

2009-01-01

Fluid Bed Bioreactor performance is strongly affected by bed void fraction or bed porosity fluctuations. Particle size enlargement due to biofilm growth is an important factor that is involved in these variations and until now there are no mathematical equations that consider biofilm growth. In this work a mathematical equation is proposed to calculate bed void fraction in an inverse fluid bed bioreactor. (Author)

Identification of defluidization region in a gas-solid fluidized bed using a method based on pressure fluctuation measurements

Directory of Open Access Journals (Sweden)

M. R. Parise

2009-09-01

Full Text Available Industrial applications that involve fluidized bed operations must prevent the undesirable phenomenon of partial or complete bed defluidization. Defluidization can be avoided by increasing the gas velocity and/or, in some cases, changing the solid feed conditions in the system, provided that the changes in the hydrodynamics of the flow are detected early enough. The use of a technique that can perform an early detection of the defluidization condition in industrial applications is important, in order to avoid the loss of efficiency or even an undesirable shutting down of the process. The objective of this work is to show the application of a method for early detection of the condition where the bed is tending to the defluidization, in a gas-solid fluidized bed flow. The method is based on pressure fluctuation measurements. Experimental tests are carried out using two solid particles: microcrystalline cellulose and sand. Results show that the proposed method is efficient in detecting the fluidization condition in a conventional bubbling bed regime. The potential of application of the technique is also shown for the control of the defluidization phenomenon in industry.

Field Marshal Erwin Rommel: the head injury that may have prolonged the Second World War.

Science.gov (United States)

Fuhrman, Heather A; Mullin, Jeffrey P; Sloffer, Chris A

2016-07-01

War-related head injury, indeed neurological injury in general, has been a part of the history of humankind for as long as there has been warfare. Such injuries can result in the removal of the individual from combat, thus eliminating any subsequent contribution that he or she might have made to the battle. However, at times, the injuries can have more wide-reaching effects. In the case of commanders or leaders, the impact of their injuries may include the loss of their influence, planning, and leadership, and thus have a disproportionate effect on the battle, or indeed the war. Field Marshal Erwin Rommel was a talented military strategist and leader who was respected by friends and foes alike. He held an honored reputation by the German people and the military leadership. His head injury on July 17, 1944, resulted in his being removed from the field of battle in northern France, but also meant that he was not able to lend his stature to the assassination attempt of Adolph Hitler on July 20. It is possible that, had he been able to lend his stature to the events, Hitler's hold on the nation's government might have been loosened, and the war might have been brought to an end a year earlier. The authors review Rommel's career, his injury, the subsequent medical treatment, and his subsequent death.

The importance of the AVR pebble-bed reactor for the future of nuclear power

International Nuclear Information System (INIS)

Pohl, P.

2006-01-01

The AVR pebble-bed high temperature gas-cooled reactor (HTGR) at Juelich (Germany)) operated from 1967 to 1988 and was certainly the most important HTGR project of the past. The reactor was the mass test bed for all development steps of HTGR pebble fuel. Some early fuel charges failed under high temperature conditions and contaminated the reactor. An accurate pebble measurement (Cs 137) allowed to clean the core from unwanted pebbles after 1981. The coolant activity went down and remained very low for the remaining reactor operation. A melt-wire experiment in 1986 revealed max. coolant temperatures of >1280 deg. C and fuel temperatures of >1350 deg. C, explained by under-estimated bypasses. The fuel still in the core achieved high burn-ups and showed under the extreme temperature conditions excellent fission product retention. Thus, the AVR operation qualified the HTGR fuel, and an average discharge burn-up of 112% fifa revealed an excellent fuel economy of the pebble-bed reactor. Furthermore, the AVR operation offers many meaningful data for code-to-experiment comparisons. (authors)

Preliminary Assessment of Primary Flight Display Symbology for Electro- Optic Head-Down Displays

Science.gov (United States)

1991-06-01

information :elated to pitch and power; the vertica! line provides information related to bank and heading. As a result of this geometrica ...steering bar are centered over the aircraft symbol. -n -1-- If the bars are centered, the aircraft is either correcting properly or is flying the desired...a•Isd bas,:ý muve to provide a new pitch command. Roll theading correction ) commands are seen as unbalanced line width, the low command bar side

Evaluation of a low-head recirculating aquaculture system used for rearing Florida pompano to market size

Science.gov (United States)

A low-head recirculating aquaculture system (RAS) was evaluated for the production Florida pompano Trachinotus carolinus from juvenile to market size. The RAS consisted of three dual-drain, 3-m diameter culture tanks of 7.8 m3 volume each, two 0.7-m3 moving bed bioreactors filled 67% with K1 kaldnes...

A eukaryotic-acquired gene by a biotrophic phytopathogen allows prolonged survival on the host by counteracting the shut-down of plant photosynthesis

KAUST Repository

Garavaglia, Betiana S.

2010-01-28

Xanthomonas citri pv. citri, the bacteria responsible for citrus canker posses a biological active plant natriuretic peptide (PNP)-like protein, not present in any other bacteria. PNPs are a class of extracellular, systemically mobile peptides that elicit a number of plant responses important in homeostasis and growth. Previously, we showed that a Xanthomonas citri pv. citri mutant lacking the PNP-like protein XacPNP produced more necrotic lesions in citrus leaves than wild type infections and suggested a role for XacPNP in the regulation of host homeostasis. Here we have analyzed the proteome modifications observed in citrus leaves infected with the wild type and XacPNP deletion mutant bacteria. While both of them cause downregulation of enzymes related to photosynthesis as well as chloroplastic ribosomal proteins, proteins related to defense responses are up-regulated. However, leaves infiltrated with the XacPNP deletion mutant show a more pronounced decrease in photosynthetic proteins while no reduction in defense related proteins as compared to the wild-type pathogen. This suggests that XacPNP serves the pathogen to maintain host photosynthetic efficiency during pathogenesis. The results from the proteomics analyses are consistent with our chlorophyll fluorescence data and transcript analyses of defense genes that show a more marked reduction in photosynthesis in the mutant but no difference in the induction of genes diagnostic for biotic-stress responses. We therefore conclude that XacPNP counteracts the shut-down of host photosynthesis during infection and in that way maintains the tissue in better conditions, suggesting that the pathogen has adapted a host gene to modify its natural host and render it a better reservoir for prolonged bacterial survival and thus for further colonization. 2010 Garavaglia et al.

A eukaryotic-acquired gene by a biotrophic phytopathogen allows prolonged survival on the host by counteracting the shut-down of plant photosynthesis

KAUST Repository

Garavaglia, Betiana S.; Thomas, Ludivine; Gottig, Natalia; Dunger, Germá n; Garofalo, Cecilia G.; Daurelio, Lucas D.; Ndimba, Bongani; Orellano, Elena G.; Gehring, Christoph A; Ottado, Jorgelina

2010-01-01

Xanthomonas citri pv. citri, the bacteria responsible for citrus canker posses a biological active plant natriuretic peptide (PNP)-like protein, not present in any other bacteria. PNPs are a class of extracellular, systemically mobile peptides that elicit a number of plant responses important in homeostasis and growth. Previously, we showed that a Xanthomonas citri pv. citri mutant lacking the PNP-like protein XacPNP produced more necrotic lesions in citrus leaves than wild type infections and suggested a role for XacPNP in the regulation of host homeostasis. Here we have analyzed the proteome modifications observed in citrus leaves infected with the wild type and XacPNP deletion mutant bacteria. While both of them cause downregulation of enzymes related to photosynthesis as well as chloroplastic ribosomal proteins, proteins related to defense responses are up-regulated. However, leaves infiltrated with the XacPNP deletion mutant show a more pronounced decrease in photosynthetic proteins while no reduction in defense related proteins as compared to the wild-type pathogen. This suggests that XacPNP serves the pathogen to maintain host photosynthetic efficiency during pathogenesis. The results from the proteomics analyses are consistent with our chlorophyll fluorescence data and transcript analyses of defense genes that show a more marked reduction in photosynthesis in the mutant but no difference in the induction of genes diagnostic for biotic-stress responses. We therefore conclude that XacPNP counteracts the shut-down of host photosynthesis during infection and in that way maintains the tissue in better conditions, suggesting that the pathogen has adapted a host gene to modify its natural host and render it a better reservoir for prolonged bacterial survival and thus for further colonization. 2010 Garavaglia et al.

Prolonged pregnancy: Methods, Causal Determinants and Outcome

DEFF Research Database (Denmark)

Olesen, Annette Wind

Summary Prolonged pregnancy, defined as a pregnancy with a gestational length of 294 days or more, is a frequent condition. It is associated with an increased risk of fetal and maternal complications. Little is known about the aetiology of prolonged pregnancy. The aims of the thesis were 1......) to study the incidence of prolonged pregnancy as a function of methods for determining gestational age; 2) to determine the risk of obstetrical and fetal complications in prolonged pregnancy; 3) to validate the self-reported gestational age in the National Birth Cohort; 4) to determine whether...... the risk of recurrence of prolonged pregnancy as a function of change in male partner and social conditions (IV). The National Birth Cohort provided data for the study on prenatal risk indicators of prolonged pregnancy in a follow-up design (V). The self-reported gestational ages from this database...

Fluid-bed combustion

Energy Technology Data Exchange (ETDEWEB)

Hunt, G.; Schoebotham, N.

1981-02-01

In Energy Equipment Company's two-stage fluidized bed system, partial combustion in a fluidized bed is followed by burn-off of the generated gases above the bed. The system can be retrofitted to existing boilers, and can burn small, high ash coal efficiently. It has advantages when used as a hot gas generator for process drying. Tests on a boiler at a Cadbury Schweppes plant are reported.

Prolonged CT urography in duplex kidney.

Science.gov (United States)

Gong, Honghan; Gao, Lei; Dai, Xi-Jian; Zhou, Fuqing; Zhang, Ning; Zeng, Xianjun; Jiang, Jian; He, Laichang

2016-05-13

Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

Apparatus for controlling fluidized beds

Science.gov (United States)

Rehmat, A.G.; Patel, J.G.

1987-05-12

An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

Experimental study of flow field characteristics on bed configurations in the pebble bed reactor

International Nuclear Information System (INIS)

Jia, Xinlong; Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jia, Haijun; Jiang, Shengyao

2017-01-01

Highlights: • PTV study of flow fields of pebble bed reactor with different configurations are carried out. • Some criteria are proposed to quantify vertical velocity field and flow uniformity. • The effect of different pebble bed configurations is also compared by the proposed criteria. • The displacement thickness is used analogically to analyze flow field characteristics. • The effect of mass flow variation in the stagnated region of the funnel flow is measured. - Abstract: The flow field characteristics are of fundamental importance in the design work of the pebble bed high temperature gas cooled reactor (HTGR). The different effects of bed configurations on the flow characteristics of pebble bed are studied through the PTV (Particle Tracking Velocimetry) experiment. Some criteria, e.g. flow uniformity (σ) and mass flow level (α), are proposed to estimate vertical velocity field and compare the bed configurations. The distribution of the Δθ (angle difference between the individual particle velocity and the velocity vector sum of all particles) is also used to estimate the resultant motion consistency level. Moreover, for each bed configuration, the thickness of displacement is analyzed to measure the effect of the funnel flow zone based on the boundary layer theory. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity and other characteristics; and the sequence of levels of each estimation criterion is obtained for all bed configurations. In addition, a good design of the pebble bed configuration is suggested and these estimation criteria can be also applied and adopted in testing other geometry designs of pebble bed.

Head-head interactions of resting myosin crossbridges in intact frog skeletal muscles, revealed by synchrotron x-ray fiber diffraction.

Directory of Open Access Journals (Sweden)

Kanji Oshima

Full Text Available The intensities of the myosin-based layer lines in the x-ray diffraction patterns from live resting frog skeletal muscles with full thick-thin filament overlap from which partial lattice sampling effects had been removed were analyzed to elucidate the configurations of myosin crossbridges around the thick filament backbone to nanometer resolution. The repeat of myosin binding protein C (C-protein molecules on the thick filaments was determined to be 45.33 nm, slightly longer than that of myosin crossbridges. With the inclusion of structural information for C-proteins and a pre-powerstroke head shape, modeling in terms of a mixed population of regular and perturbed regions of myosin crown repeats along the filament revealed that the myosin filament had azimuthal perturbations of crossbridges in addition to axial perturbations in the perturbed region, producing pseudo-six-fold rotational symmetry in the structure projected down the filament axis. Myosin crossbridges had a different organization about the filament axis in each of the regular and perturbed regions. In the regular region that lacks C-proteins, there were inter-molecular interactions between the myosin heads in axially adjacent crown levels. In the perturbed region that contains C-proteins, in addition to inter-molecular interactions between the myosin heads in the closest adjacent crown levels, there were also intra-molecular interactions between the paired heads on the same crown level. Common features of the interactions in both regions were interactions between a portion of the 50-kDa-domain and part of the converter domain of the myosin heads, similar to those found in the phosphorylation-regulated invertebrate myosin. These interactions are primarily electrostatic and the converter domain is responsible for the head-head interactions. Thus multiple head-head interactions of myosin crossbridges also characterize the switched-off state and have an important role in the regulation

Two-Phase Flow Effect on the Ex-Vessel Corium Debris Bed Formation in Severe Accident

International Nuclear Information System (INIS)

Kim, Eunho; Park, Jin Ho; Kim, Moo Hwan; Park, Hyun Sun; Ma, Weimin; Bechta, Sevostian V.

2014-01-01

In Korean IVR-ERVC(In-Vessel Retention of molten corium through External Reactor Vessel Cooling) strategy, if the situation degenerates into insufficient external vessel cooling, the molten core mixture can directly erupt into the flooded cavity pool from the weakest point of the vessel. Then, FCI (molten Fuel Coolant Interaction) will fragment the corium jet into small particulates settling down to make porous debris bed on the cavity basemat. To secure the containment integrity against the MCCI (Molten Core - Concrete Interaction), cooling of the heat generating porous corium debris bed is essential and it depends on the characteristics of the bed itself. For the characteristics of corium debris bed, many previous experimental studies with simulant melts reported the heap-like shape mostly. There were also following experiments to develop the correlation for the heap-like shaped debris bed. However, recent studies started to consider the effect of the decay heat and reported some noticeable results with the two-phase flow effect on the debris bed formation. The Kyushu University and JAEA group reported the experimental studies on the 'self-leveling' effect which is the flattening effect of the particulate bed by the inside gas generation. The DECOSIM simulation study of RIT (Royal Institute of Technology, Sweden) with Russian researchers showed the 'large cavity pool convection' effect, which is driven by the up-rising gas bubble flow from the pre-settled debris bed, on the particle settling trajectories and ultimately final bed shape. The objective of this study is verification of the two-phase flow effect on the ex-vessel corium debris bed formation in the severe accident. From the analysis on the test movie and resultant particle beds, the two-phase flow effect on the debris bed formation, which has been reported in the previous studies, was verified and the additional findings were also suggested. For the first, in quiescent pool the

Bed diameter effects and incipient slugging in gas fluidized beds

International Nuclear Information System (INIS)

Agarwal, P.K.

1986-01-01

The coalescence and growth of bubble swarms formed at the distributor of a fluidized bed gives rise to lateral as well as vertical distributions of bubble properties. However, existing models employ average bubble properties obtained largely from semi-empirical considerations. In a recent Paper, the author developed a bubble growth model based on a population balance approach. Analytical expressions were derived for the bubble characteristic distributions and averages. However, the model, developed for unconstrained growth, did not take into account the effect of the bed diameter and the possibility of slugging. In this Paper, the model is extended to take these aspects into account. A slugging criterion is also developed which is expected to be valid for the regime where incipient slugging depends on the bed height as well as the region where bed height does not significantly affect minimum slugging conditions

Effect of β-hydroxy-β-methylbutyrate (HMB) on lean body mass during 10 days of bed rest in older adults.

Science.gov (United States)

Deutz, Nicolaas E P; Pereira, Suzette L; Hays, Nicholas P; Oliver, Jeffery S; Edens, Neile K; Evans, Chris M; Wolfe, Robert R

2013-10-01

Loss of muscle mass due to prolonged bed rest decreases functional capacity and increases hospital morbidity and mortality in older adults. To determine if HMB, a leucine metabolite, is capable of attenuating muscle decline in healthy older adults during complete bed rest. A randomized, controlled, double-blinded, parallel-group design study was carried out in 24 healthy (SPPB ≥ 9) older adult subjects (20 women, 4 men), confined to complete bed rest for ten days, followed by resistance training rehabilitation for eight weeks. Subjects in the experimental group were treated with HMB (calcium salt, 1.5 g twice daily - total 3 g/day). Control subjects were treated with an inactive placebo powder. Treatments were provided starting 5 days prior to bed rest till the end rehabilitation phase. DXA was used to measure body composition. Nineteen eligible older adults (BMI: 21-33; age: 60-76 year) were evaluable at the end of the bed rest period (Control n = 8; Ca-HMB n = 11). Bed rest caused a significant decrease in total lean body mass (LBM) (2.05 ± 0.66 kg; p = 0.02, paired t-test) in the Control group. With the exclusion of one subject, treatment with HMB prevented the decline in LBM over bed rest -0.17 ± 0.19 kg; p = 0.23, paired t-test). There was a statistically significant difference between treatment groups for change in LBM over bed rest (p = 0.02, ANOVA). Sub-analysis on female subjects (Control = 7, HMB = 8) also revealed a significant difference in change in LBM over bed rest between treatment groups (p = 0.04, ANOVA). However, differences in function parameters could not be observed, probably due to the sample size of the study. In healthy older adults, HMB supplementation preserves muscle mass during 10 days of bed rest. These results need to be confirmed in a larger trial. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Strategic Style in Pared-Down Poker

Science.gov (United States)

Burns, Kevin

This chapter deals with the manner of making diagnoses and decisions, called strategic style, in a gambling game called Pared-down Poker. The approach treats style as a mental mode in which choices are constrained by expected utilities. The focus is on two classes of utility, i.e., money and effort, and how cognitive styles compare to normative strategies in optimizing these utilities. The insights are applied to real-world concerns like managing the war against terror networks and assessing the risks of system failures. After "Introducing the Interactions" involved in playing poker, the contents are arranged in four sections, as follows. "Underpinnings of Utility" outlines four classes of utility and highlights the differences between them: economic utility (money), ergonomic utility (effort), informatic utility (knowledge), and aesthetic utility (pleasure). "Inference and Investment" dissects the cognitive challenges of playing poker and relates them to real-world situations of business and war, where the key tasks are inference (of cards in poker, or strength in war) and investment (of chips in poker, or force in war) to maximize expected utility. "Strategies and Styles" presents normative (optimal) approaches to inference and investment, and compares them to cognitive heuristics by which people play poker--focusing on Bayesian methods and how they differ from human styles. The normative strategy is then pitted against cognitive styles in head-to-head tournaments, and tournaments are also held between different styles. The results show that style is ergonomically efficient and economically effective, i.e., style is smart. "Applying the Analysis" explores how style spaces, of the sort used to model individual behavior in Pared-down Poker, might also be applied to real-world problems where organizations evolve in terror networks and accidents arise from system failures.

Temporal Changes in Left Ventricular Mechanics: Impact of Bed Rest and Exercise

Science.gov (United States)

Scott, Jessica M.; Matz, Timothy; Caine, Timothy; Martin, David S.; Downs, Meghan; Ploutz-Snyder, Lori

2014-01-01

BACKGROUND Current techniques used to assess cardiac function following spaceflight or head-down tilt bed rest (HDTBR) involve invasive and time consuming procedures such as Swan-Ganz catheterization or cardiac magnetic resonance imaging. An alternative approach, echocardiography, can monitor cardiac morphology and function via sequential measurements of left ventricular (LV) mass and ejection fraction (EF). However, LV mass and EF are insensitive measures of early (subclinical) cardiac deconditioning, and a decrease in LV mass and EF become evident only once significant deconditioning has already occurred. The use of more sensitive and specific echocardiographic techniques such as speckle tracking imaging may address the current limitations of conventional cardiac imaging techniques to provide insight into the magnitude and time course of cardiac deconditioning. METHODS Speckle tracking assessment of longitudinal, radial, and circumferential strain and twist was used to evaluate the impact of 70 days of HDTBR (n=7) and HDTBR + exercise (n=11) on temporal changes in LV mechanics. Echocardiograms were performed pre (BR-2), during (BR31, 70), and following (BR+4hr) HDTBR. Multi-level modeling was used to evaluate the effect of HDTBR condition (Control, Exercise) on cardiac variables. RESULTS Compared to BR-2, longitudinal (BR-2: - 19.0 +/- 1.8%; BR31: -15.9 +/- 2.4%; BR70: -14.9 +/- 2.4%; BR+4hr: -16.0 +/- 2.1%) and radial (BR-2: 15.0 +/- 1.9%; BR31: 12.3 +/- 2.4%; BR70: 11.3 +/- 2.2%; BR+4hr: 13.5 +/- 2.5% ) strains were significantly impaired during and following bed rest (pmechanics for longitudinal strain (BR-2: -19.1 +/- 1.5%; BR 31: -19.0 +/- 2.4%; BR70: -19.1 +/- 2.7%; BR+4hr: -17.8 +/- 2.1%), radial strain (BR-2: 13.8 +/- 2.4; BR31: 14.7 +/- 2.4; BR70: 14.4 +/- 1.6; BR+4hr: 14.4 +/- 2.4), and twist (BR-2: 17.8 +/- 3.6deg; BR31: 18.0 +/- 3.6deg; BR70: 18.2 +/- 5.9deg; BR+4hr: 18.3 +/- 4.2deg). CONCLUSIONS Speckle-tracking echocardiography provides important

Head-down posture in glaucoma suspects induces changes in IOP, systemic pressure and PERG that predict future loss of optic nerve tissue

Science.gov (United States)

Porciatti, Vittorio; Feuer, William J.; Monsalve, Pedro; Triolo, Giacinto; Vazquez, Luis; McSoley, John; Ventura, Lori M.

2017-01-01

Purpose To obtain pilot data on posture-induced changes of IOP, systemic pressure and pattern electroretinogram (PERG) predictive of future optic nerve tissue loss glaucoma suspects (GS). Methods Mean peripapillary retinal fiber layer thickness (RNFLT) was measured with OCT two times/year in 28 GS aged 58 ± 8.9 years over 5.0 ± 0.73 years. All patients had a baseline PERG, IOP and brachial blood pressure measurements in the seated and – 10 degrees head-down-body-tilt position (HDT). Outcome measures were seated/HDT PERG amplitude and phase, IOP, mean arterial blood pressure (MAP), and estimated ocular perfusion pressure (OPP). An additional group of 11 similarly-aged controls (SAC) aged 56.9 ± 13 years was tested for comparison. Results While all GS had initial RNFLT in the normal range, 9/28 of them developed significant (P blood pressure, together with their changes upon HDT, may have predictive value for future loss of optic nerve tissue in GS. This study supports the rationale for a full-scale clinical trial to identify patients at high-risk of development of glaucoma. PMID:28263259

Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

International Nuclear Information System (INIS)

Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao

2014-01-01

Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

Visualization of bed material movement in a simulated fluidized bed heat exchanger by neutron radiography

International Nuclear Information System (INIS)

Umekawa, Hisashi; Ozawa, Mamoru; Takenaka, Nobuyuki; Matsubayashi, Masahito

1999-01-01

The bulk movement of fluidized bed material was visualized by neutron radiography by introducing tracers into the bed materials. The simulated fluidized bed consisted of aluminum plates, and the bed material was sand of 99.7% SiO 2 (mean diameter: 0.218 mm, density: 2555 kg/m 3 ). Both materials were almost transparent to neutrons. Then the sand was colored by the contamination of the sand coated by CdSO 4 . Tracer particles of about 2 mm diameter were made by the B 4 C, bonded by the vinyl resin. The tracer was about ten times as large as the particle of fluidized bed material, but the traceability was enough to observe the bed-material bulk movement owing to the large effective viscosity of the fluidized bed. The visualized images indicated that the bubbles and/or wakes were important mechanism of the behavior of the fluidized bed movement

Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

Energy Technology Data Exchange (ETDEWEB)

Badger, Phillip C.; Dunn, Jr., Kenneth J.

2015-09-01

A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

[Brain function recovery after prolonged posttraumatic coma].

Science.gov (United States)

Klimash, A V; Zhanaidarov, Z S

2016-01-01

To explore the characteristics of brain function recovery in patients after prolonged posttraumatic coma and with long-unconscious states. Eighty-seven patients after prolonged posttraumatic coma were followed-up for two years. An analysis of a clinical/neurological picture after a prolonged episode of coma was based on the dynamics of vital functions, neurological status and patient's reactions to external stimuli. Based on the dynamics of the clinical/neurological picture that shows the recovery of functions of the certain brain areas, three stages of brain function recovery after a prolonged episode of coma were singled out: brain stem areas, diencephalic areas and telencephalic areas. These functional/anatomic areas of brain function recovery after prolonged coma were compared to the present classifications.

Fluidised bed combustion system

International Nuclear Information System (INIS)

McKenzie, E.C.

1976-01-01

Fluidized bed combustion systems that facilitates the maintenance of the depth of the bed are described. A discharge pipe projects upwardly into the bed so that bed material can flow into its upper end and escape downwardly. The end of the pipe is surrounded by an enclosure and air is discharged into the enclosure so that material will enter the pipe from within the enclosure and have been cooled in the enclosure by the air discharged into it. The walls of the enclosure may themselves be cooled

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

Energy Technology Data Exchange (ETDEWEB)

Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-05-06

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

International Nuclear Information System (INIS)

Hansen, E. K.

2015-01-01

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

Researchers solve big mysteries of pebble bed reactor

Energy Technology Data Exchange (ETDEWEB)

Shams, Afaque; Roelofs, Ferry; Komen, E.M.J. [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Baglietto, Emilio [Massachusetts Institute of Technology, Cambridge, MA (United States). Dept. of Nuclear Science and Engineering; Sgro, Titus [CD-adapco, London (United Kingdom). Technical Marketing

2014-03-15

The PBR is one type of High Temperature Reactors, which allows high temperature work while preventing the fuel from melting (bringing huge safety margins to the reactor) and high electricity efficiency. The design is also highly scalable; a plant could be designed to be as large or small as needed, and can even be made mobile, allowing it to be used onboard a ship. In a PBR, small particles of nuclear fuel, embedded in a moderating graphite pebble, are dropped into the reactor as needed. At the bottom, the pebbles can be removed simply by opening a small hatch and letting gravity pull them down. To cool the reactor and create electricity, helium gas is pumped through the reactor to pull heat out which is then run through generators. One of the most difficult problems to deal with has been the possible appearance of local temperature hotspots within the pebble bed heating to the point of melting the graphite moderators surrounding the fuel. Obviously, constructing a reactor and experimenting to investigate this possibility is out of the question. Instead, nuclear engineers have been attempting to simulate a PBR with various CFD codes. The thermo-dynamic analysis to simulate realistic conditions in a pebble bed are described and the results are shown. (orig.)

Fluidized bed reactor for processing particles coated with carbon

International Nuclear Information System (INIS)

Marschollek, M.; Simon, W.; Walter, C.

1978-01-01

The carbon coating of production returns of these particles first has to be removed before the heavy metal core released can be reprocessed. For reasons of criticality, removal of burnt-up particles downwards must be possible in the fluidized bed reactor even if the reactor diameter is greater than 800 mm, and the material temperatures must not exceed 650 0 C. It consists of an upper cylindrical and a lower conical part, where, according to the invention, the gas distributor heads in the conical part are situated in several planes above one another for the fluidisation and combustion gas and where they are evently distributed over the reactor crossection, so that an even flow profile is achieved over the reactor cross section. (HP) [de

Bacillus cereus in free-stall bedding.

Science.gov (United States)

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the

Head position modulates optokinetic nystagmus.

Science.gov (United States)

Pettorossi, V E; Ferraresi, A; Botti, F M; Panichi, R; Barmack, N H

2011-08-01

Orientation and movement relies on both visual and vestibular information mapped in separate coordinate systems. Here, we examine how coordinate systems interact to guide eye movements of rabbits. We exposed rabbits to continuous horizontal optokinetic stimulation (HOKS) at 5°/s to evoke horizontal eye movements, while they were statically or dynamically roll-tilted about the longitudinal axis. During monocular or binocular HOKS, when the rabbit was roll-tilted 30° onto the side of the eye stimulated in the posterior → anterior (P → A) direction, slow phase eye velocity (SPEV) increased by 3.5-5°/s. When the rabbit was roll-tilted 30° onto the side of the eye stimulated in the A → P direction, SPEV decreased to ~2.5°/s. We also tested the effect of roll-tilt after prolonged optokinetic stimulation had induced a negative optokinetic afternystagmus (OKAN II). In this condition, the SPEV occurred in the dark, "open loop." Modulation of SPEV of OKAN II depended on the direction of the nystagmus and was consistent with that observed during "closed loop" HOKS. Dynamic roll-tilt influenced SPEV evoked by HOKS in a similar way. The amplitude and the phase of SPEV depended on the frequency of vestibular oscillation and on HOKS velocity. We conclude that the change in the linear acceleration of the gravity vector with respect to the head during roll-tilt modulates the gain of SPEV depending on its direction. This modulation improves gaze stability at different image retinal slip velocities caused by head roll-tilt during centric or eccentric head movement.

Astronomical cycle origin of bedded chert: A middle Triassic bedded chert sequence, Inuyama, Japan

Science.gov (United States)

Ikeda, Masayuki; Tada, Ryuji; Sakuma, Hironobu

2010-09-01

Astronomical forcing is one of the main drivers of climate change, and astronomical cyclicity recorded in sediments provides a clue to understand the dynamics of the global climate system. Bedded cherts consist of rhythmic alternations of chert and shale beds. Although previous studies have hypothesized that the origin of bedded chert is related to astronomical cycles (e.g. Fischer, 1976; Hori et al., 1993), conclusive proof remains elusive. To explore this possibility, we established a continuous, high-resolution lithostratigraphy of middle Triassic bedded chert in Central Japan. The average duration of each chert-shale couplet is 20 kyr, similar to that of the precession cycle. Spectral analysis of a bed number series of thickness variations in chert beds was performed assuming that each chert-shale couplet represents a 20-kyr precession cycle. The results reveal cycles involving approximately 200, 20, 5, and 2-3 beds, corresponding to periodicities of approximately 4000, 400, 100, and 40-60 kyr, respectively. By further assuming that the 20-bed cycle represents a 405-kyr eccentricity cycle of constant and stable periodicity, we converted the bed number series to a time series. Spectral analysis of the time series revealed distinct periodicities of 3600, 117, 97, and 38 kyr, in addition to 405 kyr. Besides 3600 kyr, these periodicities agree well with the 120, 95, and 37 kyr periodicities for eccentricity cycles and the obliquity cycle during the Triassic. Moreover, we detected amplitude modulation of the approximately 100-kyr cycle of thickness variations in chert beds with a 405-kyr periodicity, which may correspond to amplitude modulation of 100-kyr climatic precession cycle with the 405-kyr periodicity. The approximately 3600-kyr periodicity described above and 1800-kyr periodicity manifested as the amplitude modulation of the 405-kyr cycle are correlated to present-day long-term eccentricity cycles of 2400 and 4800 kyr evolved by chaotic behavior of solar

Cephalometrics in children with Down's syndrome

International Nuclear Information System (INIS)

Quintanilla, Juan Suarez; Biedma, Benjamin Martin; Rodriguez, Maximino Quintans; Mora, Maria Teresa Jorge; Cunqueiro, Maria Mercedes Suarez; Pazos, Mayte Abeleira

2002-01-01

Heading AbstractAims. To describe the craniofacial morphology of a group of patients with Down's syndrome using a cephalometric analysis of the lateral skull radiograph.Materials and methods. The studied sample consisted of 39 patients with Down's syndrome (24 boys, 15 girls) ranging from 7 to 18 years of age. The computerized cephalometric study of the lateral skull radiograph of each patient was carried out using the method described by Ricketts.Results.Anterior cross-bite was observed in 38.4% of patients and diminished interincisal angle in 77%. Skeletal parameters matched the clinical norm, indicating mesofacial biotype, i.e., normal maxillomandibular growth. The lower incisors protruded in 84.6% of the individuals studied and were proinclined in 77%; upper incisors were protruded in 77% of the sample. The lower lip protruded in 84.6%. Analysis of craniofacial parameters showed average values within the clinical norm. Analysis of the inner cranium demonstrated normal inclination of the cranial base, while the length of the anterior skull base was diminished in 53.8%.Conclusions. From the skeletal perspective, patients with Down's syndrome who are in a period of growth demonstrate a reduction of the anterior skull base. From the dentoalveolar perspective, they show protrusion and proinclination of lower incisors, which is related to a tendency to anterior cross-bite and, to a lesser extent, to diminished overbite. Likewise, the lower lip protrusion observed in this study is related to the position of the lower incisor. (orig.)

Chemical effects head-loss research in support of generic safety issue 191.

Energy Technology Data Exchange (ETDEWEB)

Park, J. H.; Kasza, K.; Fisher, B.; Oras, J.; Natesan, K.; Shack, W. J.; Nuclear Engineering Division

2006-10-31

This summary report describes studies conducted at Argonne National Laboratory on the potential for chemical effects on head loss across sump screens. Three different buffering solutions were used for these tests: trisodium phosphate (TSP), sodium hydroxide, and sodium tetraborate. These pH control agents used following a LOCA at a nuclear power plant show various degrees of interaction with the insulating materials Cal-Sil and NUKON. Results for Cal-Sil dissolution tests in TSP solutions, settling rate tests of calcium phosphate precipitates, and benchmark tests in chemically inactive environments are also presented. The dissolution tests were intended to identify important environmental variables governing both calcium dissolution and subsequent calcium phosphate formation over a range of simulated sump pool conditions. The results from the dissolution testing were used to inform both the head loss and settling test series. The objective of the head loss tests was to assess the head loss produced by debris beds created by Cal-Sil, fibrous debris, and calcium phosphate precipitates. The effects of both the relative arrival time of the precipitates and insulation debris and the calcium phosphate formation process were specifically evaluated. The debris loadings, test loop flow rates, and test temperature were chosen to be reasonably representative of those expected in plants with updated sump screen configurations, although the approach velocity of 0.1 ft/s used for most of the tests is 3-10 times that expected in plants with large screens . Other variables were selected with the intent to reasonably bound the head loss variability due to arrival time and calcium phosphate formation uncertainty. Settling tests were conducted to measure the settling rates of calcium phosphate precipitates (formed by adding dissolved Ca to boric acid and TSP solutions) in water columns having no bulk directional flow. For PWRs where NaOH and sodium tetraborate are used to control

QT Prolongation due to Graves’ Disease

Directory of Open Access Journals (Sweden)

Zain Kulairi

2017-01-01

Full Text Available Hyperthyroidism is a highly prevalent disease affecting over 4 million people in the US. The disease is associated with many cardiac complications including atrial fibrillation and also less commonly with ventricular tachycardia and fibrillation. Many cardiac pathologies have been extensively studied; however, the relationship between hyperthyroidism and rate of ventricular repolarization manifesting as a prolonged QTc interval is not well known. Prolonged QTc interval regardless of thyroid status is a risk factor for cardiovascular mortality and life-threatening ventricular arrhythmia. The mechanism regarding the prolongation of the QT interval in a hyperthyroid patient has not been extensively investigated although its clinical implications are relevant. Herein, we describe a case of prolonged QTc in a patient who presented with signs of hyperthyroidism that was corrected with return to euthyroid status.

Heading and head injuries in soccer.

Science.gov (United States)

Kirkendall, D T; Jordan, S E; Garrett, W E

2001-01-01

In the world of sports, soccer is unique because of the purposeful use of the unprotected head for controlling and advancing the ball. This skill obviously places the player at risk of head injury and the game does carry some risk. Head injury can be a result of contact of the head with another head (or other body parts), ground, goal post, other unknown objects or even the ball. Such impacts can lead to contusions, fractures, eye injuries, concussions or even, in rare cases, death. Coaches, players, parents and physicians are rightly concerned about the risk of head injury in soccer. Current research shows that selected soccer players have some degree of cognitive dysfunction. It is important to determine the reasons behind such deficits. Purposeful heading has been blamed, but a closer look at the studies that focus on heading has revealed methodological concerns that question the validity of blaming purposeful heading of the ball. The player's history and age (did they play when the ball was leather and could absorb significant amounts of water), alcohol intake, drug intake, learning disabilities, concussion definition and control group use/composition are all factors that cloud the ability to blame purposeful heading. What does seem clear is that a player's history of concussive episodes is a more likely explanation for cognitive deficits. While it is likely that the subconcussive impact of purposeful heading is a doubtful factor in the noted deficits, it is unknown whether multiple subconcussive impacts might have some lingering effects. In addition, it is unknown whether the noted deficits have any affect on daily life. Proper instruction in the technique is critical because if the ball contacts an unprepared head (as in accidental head-ball contacts), the potential for serious injury is possible. To further our understanding of the relationship of heading, head injury and cognitive deficits, we need to: learn more about the actual impact of a ball on the

Biological regeneration of humic acid-loaded partially exhausted activated carbon (down flow system)

International Nuclear Information System (INIS)

Durrani, M.A.Q.J.; Martin, R.J.; Khaliq, F.

1995-01-01

This paper represents the report on the biological regeneration of partially exhausted (down flow) activated carbon following the experimental studies carried out at the university of Birmingham, UK. The Research investigated the extent of bio regeneration of humic acid of concentration 100 mg/l. Bio regeneration in the partial exhaustion system (down flow) was evaluated in terms of substrate removal. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents. The regeneration performance of the bio regeneration, partially exhausted (with humic acid) carbon increased during initial cycles, later on, it deteriorated significantly with each successive regeneration cycle. Microbial fouling of the carbon, especially at the bottom of the carbon bed was found to produce a substantial deterioration of the bio regeneration performance. (author)

Secondary Waste Form Down-Selection Data Package—Fluidized Bed Steam Reforming Waste Form

Energy Technology Data Exchange (ETDEWEB)

Qafoku, Nikolla; Westsik, Joseph H.; Strachan, Denis M.; Valenta, Michelle M.; Pires, Richard P.

2011-09-12

The Hanford Site in southeast Washington State has 56 million gallons of radioactive and chemically hazardous wastes stored in 177 underground tanks (ORP 2010). The U.S. Department of Energy (DOE), Office of River Protection (ORP), through its contractors, is constructing the Hanford Tank Waste Treatment and Immobilization Plant (WTP) to convert the radioactive and hazardous wastes into stable glass waste forms for disposal. Within the WTP, the pretreatment facility will receive the retrieved waste from the tank farms and separate it into two treated process streams. These waste streams will be vitrified, and the resulting waste canisters will be sent to offsite (high-level waste [HLW]) and onsite (immobilized low-activity waste [ILAW]) repositories. As part of the pretreatment and ILAW processing, liquid secondary wastes will be generated that will be transferred to the Effluent Treatment Facility (ETF) on the Hanford Site for further treatment. These liquid secondary wastes will be converted to stable solid waste forms that will be disposed of in the Integrated Disposal Facility (IDF). To support the selection of a waste form for the liquid secondary wastes from WTP, Washington River Protection Solutions (WRPS) has initiated secondary waste form testing work at Pacific Northwest National Laboratory (PNNL). In anticipation of a down-selection process for a waste form for the Solidification Treatment Unit to be added to the ETF, PNNL is developing data packages to support that down-selection. The objective of the data packages is to identify, evaluate, and summarize the existing information on the four waste forms being considered for stabilizing and solidifying the liquid secondary wastes. At the Hanford Site, the FBSR process is being evaluated as a supplemental technology for treating and immobilizing Hanford LAW radioactive tank waste and for treating secondary wastes from the WTP pretreatment and LAW vitrification processes.

Exhaustion from prolonged gambling

Directory of Open Access Journals (Sweden)

Fatimah Lateef

2013-01-01

Full Text Available Complaints of fatigue and physical exhaustion are frequently seen in the acute medical setting, especially amongst athletes, army recruits and persons involved in strenuous and exertional physical activities. Stress-induced exhaustion, on the other hand, is less often seen, but can present with very similar symptoms to physical exhaustion. Recently, three patients were seen at the Department of Emergency Medicine, presenting with exhaustion from prolonged involvement in gambling activities. The cases serve to highlight some of the physical consequences of prolonged gambling.

Establishing Bedding Requirements during Transport and Monitoring Skin Temperature during Cold and Mild Seasons after Transport for Finishing Pigs

Directory of Open Access Journals (Sweden)

John McGlone

2014-05-01

Full Text Available The broad aim of this study was to determine whether bedding level in the transport trailer influenced pig performance and welfare. Specifically, the objective was to define the bedding requirements of pigs during transportation in commercial settings during cold and mild weather. Animals (n = 112,078 pigs on 572 trailers used were raised in commercial finishing sites and transported in trailers to commercial processing plants. Dead on arrival (DOA, non-ambulatory (NA, and total dead and down (D&D data were collected and skin surface temperatures of the pigs were measured by infrared thermography. Data were collected during winter (Experiment 1 and fall/spring (Experiment 2. Total D&D percent showed no interaction between bedding level and outside air temperature in any experiments. Average skin surface temperature during unloading increased with outside air temperature linearly in both experiments (P < 0.01. In conclusion, over-use of bedding may be economically inefficient. Pig skin surface temperature could be a useful measure of pig welfare during or after transport.

Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

Science.gov (United States)

Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

Uremic retention solute indoxyl sulfate level is associated with prolonged QTc interval in early CKD patients.

Directory of Open Access Journals (Sweden)

Wei-Hua Tang

Full Text Available Total mortality and sudden cardiac death is highly prevalent in patients with chronic kidney disease (CKD. In CKD patients, the protein-bound uremic retention solute indoxyl sulfate (IS is independently associated with cardiovascular disease. However, the underlying mechanisms of this association have yet to be elucidated. The relationship between IS and cardiac electrocardiographic parameters was investigated in a prospective observational study among early CKD patients. IS arrhythmogenic effect was evaluated by in vitro cardiomyocyte electrophysiological study and mathematical computer simulation. In a cohort of 100 early CKD patients, patients with corrected QT (QTc prolongation had higher IS levels. Furthermore, serum IS level was independently associated with prolonged QTc interval. In vitro, the delay rectifier potassium current (IK was found to be significantly decreased after the treatment of IS in a dose-dependent manner. The modulation of IS to the IK was through the regulation of the major potassium ion channel protein Kv 2.1 phosphorylation. In a computer simulation, the decrease of IK by IS could prolong the action potential duration (APD and induce early afterdepolarization, which is known to be a trigger mechanism of lethal ventricular arrhythmias. In conclusion, serum IS level is independently associated with the prolonged QTc interval in early CKD patients. IS down-regulated IK channel protein phosphorylation and the IK current activity that in turn increased the cardiomyocyte APD and QTc interval in vitro and in the computer ORd model. These findings suggest that IS may play a role in the development of arrhythmogenesis in CKD patients.

Biodegradation of phenolic waste liquors in stirred-tank, packed-bed, and fluidized-bed bioreactors

Energy Technology Data Exchange (ETDEWEB)

Holladay, D W; Hancher, G W; Chilcote, D D; Scott, C D

1978-11-01

The biological degradation of phenolic scrub liquors similar to those that arise in coal conversion processes was studied for symbiotic bacterial populations contained in a continuously stirred tank bioreactor, a three-phase packed-bed bioreactor, and a three-phase, fluidized-bed bioreactor. The conversions of phenol compounds were comparable in the three-phase, packed-bed bioreactor and the continuously stirred tank bioreactor; however, the packed-bed bioreactor degradation rates were as much as twice those in the continuously stirred tank bioreactor, and packed-bed bioreactor retention times were as low as one- tenth those of the continuously stirred tank bioreactors (minimum time was 12 hours).

9. Nuclear power plant service life prolongation

International Nuclear Information System (INIS)

Evropin, S.V.

1998-01-01

The problem of prolongation of nuclear power plant service life duration is discussed. A schematic diagram of the program developed in the course of activities dealing with NPP service time prolongation is shown and analyzed in details. It is shown that the basic moment when determining the strategy for NPP service time prolongation is the positive confirmation of the agreement between the NPP safety provisions and modern safety requirements. The other very important aspect of the problem is engineering substantiation of the measures assuring the reactor operation prolongation. The conclusion is made that available methods of recovering reactor materials properties, main components repair and replacement, the modern techniques for nondestructive testing of metals and NPP pipelines, as well as the developed approaches to reactor facility safety improvements make the prolongation of the Russian NPP service lifetimes possible from engineering viewpoint and economically desirable

Head spray nozzle in reactor pressure vessel

International Nuclear Information System (INIS)

Hatano, Shun-ichi.

1990-01-01

In a reactor pressure vessel of a BWR type reactor, a head spray nozzle is used for cooling the head of the pressure vessel and, in view of the thermal stresses, it is desirable that cooling is applied as uniformly as possible. A conventional head spray is constituted by combining full cone type nozzles. Since the sprayed water is flown down upon water spraying and the sprayed water in the vertical direction is overlapped, the flow rate distribution has a high sharpness to form a shape as having a maximum value near the center and it is difficult to obtain a uniform flow rate distribution in the circumferential direction. Then, in the present invention, flat nozzles each having a spray water cross section of laterally long shape, having less sharpness in the circumferential distribution upon spraying water to the inner wall of the pressure vessel and having a wide angle of water spray are combined, to make the flow rate distribution of spray water uniform in the inner wall of the pressure vessel. Accordingly, the pressure vessel can be cooled uniformly and thermal stresses upon cooling can be decreased. (N.H.)

Bed and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, Gabon.

Science.gov (United States)

Iwata, Yuji; Ando, Chieko

2007-01-01

In this paper we describe bed (nest) and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, south-eastern Gabon. During an eight-month study 44 bed sites and 506 beds were found. Among these, 38.6% of bed sites and 4.1% of beds were reused. We analyzed the monthly frequency of bed-site reuse in relation to rainfall, fruit abundance, and fruit consumption by the gorillas. The different frequency of bed-site reuse in the rainy and dry seasons was not significant. More bed-site reuse was observed during the fruiting season than during the non-fruiting season. Results from fecal analysis suggested that gorillas ate more fruit in the fruiting season than in the non-fruiting season. The frugivorous diet of western gorillas may possibly cause gorillas to stay in some areas and, consequently, reuse their bed sites. Reuse of bed sites by gorillas suggests their frequent return to an area where preferred fruit is readily available. A higher percentage of arboreal beds may also affect bed-site reuse, because of the shortage of bed material.

Safety information on QT-interval prolongation

DEFF Research Database (Denmark)

Warnier, Miriam J; Holtkamp, Frank A; Rutten, Frans H

2014-01-01

Prolongation of the QT interval can predispose to fatal ventricular arrhythmias. Differences in QT-labeling language can result in miscommunication and suboptimal risk mitigation. We systematically compared the phraseology used to communicate on QT-prolonging properties of 144 drugs newly approve...

[Phenotypic plasticity and its regulation of tillers prolonged reproductive growth of Puccinellia tenuiflora population on alkalized meadow in Songnen Plains of China].

Science.gov (United States)

Sun, Ju; Yang, Yun-Fei

2007-04-01

Puccinellia tenuiflora is a salt-tolerant plant of grass family. By the method of random sampling, big samples of reproductive tillers of P. tenuiflora population on the alkalized meadow in the Songnen Plains of China were collected at early heading, heading, flowering, and milky stages, respectively, and the plasticity of their quantitative characters was analyzed. The results showed that except some fluctuations at flowering stage, the tiller height, tiller biomass, spike length and spike biomass of the reproductive tillers at other three growth stages increased significantly every five days with the increasing time of reproductive growth. At each growth stage, tiller height had a significant positive correlation with spike biomass, but a negative correlation with reproductive allocation. With the time of reproductive growth prolonged, the increasing rate of spike biomass at early heading, flowering and milky stages increased in power function with the increase of tiller height. The reproductive allocation decreased linearly by 43.2% and 44.31% at early heading and heading stages, respectively when the reproductive growth time increased ten days, and by 130% at milky stage when the time increased five days. The regulation of the tiller phenotypic plasticity of P. tenuiflora population at its reproductive growth stage followed definite patterns.

The effect of vibration on bed voidage behaviors in fluidized beds with large particles

Directory of Open Access Journals (Sweden)

H. Jin

2007-09-01

Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

Effects of 30-, 60-, and 90-Day Bed Rest on Postural Control in Men and Women

Science.gov (United States)

Esteves, Julie; Taylor, Laura C.; Vanya, Robert D.; Dean, S. Lance; Wood, Scott J.

2011-01-01

INTRODUCTION Head-down-tilt bed rest (HDT) has been used as a safe gr ound-based analog to mimic and develop countermeasures for the physiological effects of spaceflight, including decrements in postural stability. The purpose of this investigation was to characterize the effects of 30-, 60-, and 90-day bed rest on postural control in men and women. METHODS Twenty-nine subjects (18M,11F) underwent 13 days of ambula tory acclimatization and were placed in 6? HDT for 30 (n=12), 60 (n=8), or 90 (n=9) days, followed by 14 days of ambulatory recovery. Computerized dynamic posturography (CDP) was used to assess changes in sensory and motor components of postural control, and recovery after HDT. Sensory Organization Tests (SOTs) objectively evaluate one?s ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Stability during the SOTs was assessed using peak-to-peak sway and convergence toward stability limits to derive an equilibrium score. Motor Control Tests (MCTs) evaluate one?s ability to recover from unexpected support surface perturbations, with performance determined by center-of-pressure path length. Whole-body kinematic data were collected to determine body-sway strategy used to maintain stability during each condition. Baselines were determined pre-HDT. Recovery was tracked post-HDT on days 0, 1, 2, and 4. RESULTS Immediately after HDT, subjects showed decreased performance on most SOTs, primarily on sway-referenced support conditions, typically returning to baseline levels within 4 days. MCT performance was not significantly affected. There were no significant gender or duration differences in performance. Kinematic data revealed a tendency to use ankle strategy to maintain an upright stance during most SOT conditions. Interestingly, six subjects (2M,4F) experienced orthostatic intolerance and were unable to complete day 0 testing. CONCLUSION HDT mimics some un loading mechanisms of spaceflight and

Small and low head pumped storage projects

International Nuclear Information System (INIS)

Makarechian, A.H.

1991-01-01

The purpose of this paper is to focus attention on small and low head pumped storage projects. These projects may be defined as having a capacity of less than 200-300 MW and down to about 20 MW, with heads of 1200 ft to about 300 ft or less. Many advantages of these smaller pumped storage projects include more flexibility in siting of a project, considerably shorter licensing and construction period, adaptability to closed system design concept to reduce adverse environmental impacts, considerably reduced risks of delays and substantial cost over-runs, better suited to meeting peaking capacity requirements for individual utilities, and much less transmission inter-connection requirements. An overall licensing and construction schedule of about 3 to 3 1/2 years is realistic for many smaller pumped storage projects, and competitive costs in terms of dollars per kW installed can be achieved

Genetic influence on prolonged gestation

DEFF Research Database (Denmark)

Laursen, Maja; Bille, Camilla; Olesen, Annette Wind

2004-01-01

OBJECTIVE: The purpose of this study was to test a possible genetic component to prolonged gestation. STUDY DESIGN: The gestational duration of single, first pregnancies by both female and male twins was obtained by linking the Danish Twin Registry, The Danish Civil Registration System, and the D...... factors. CONCLUSION: Maternal genes influence prolonged gestation. However, a substantial paternal genetic influence through the fetus was not found....

Gadolinium removal from the moderator system of TAPP - 3 using the three layer bed

International Nuclear Information System (INIS)

Tripathi, V.S.; Balaji, V.; Venkateswaran, G.; Dash, S.C.

2008-01-01

Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the column was deuterated with heavy water (> 99.75 % w/w) at a steady flow rate of 280 ml/min. After achieving high-grade isotopic purity viz. > 99.75 % w/w., these columns were preserved for their use after SDS - 2 actuation in the plant. Biennial Shut Down (BSD) of Unit - 3 was taken on 04-05-08 by SDS-2 actuation resulting in 16.37 ppm Gd in the moderator system. Gd removal to the extent about 8 mg/kg as designed could be done on one three layer bed. The use of this bed has resulted in an iso-pH regime at the column inlet and outlet. Conductivity values observed in the system were within the specifications. The three layer bed of a configuration slightly modified from the one tested in this work is expected to improve the column efficiency to 100% from the presently observed 87% and 97% respectively for the IX-2 and IX-3. (author)

Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

Directory of Open Access Journals (Sweden)

Arlene Garcia

2014-12-01

Full Text Available The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding; >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 6,000 pig observations. “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01. Providing bedding reduced (P < 0.05 scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01. Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was

Experimental studies on the coolability of packed beds. Flooding of hot dry packed beds

International Nuclear Information System (INIS)

Leininger, S.; Kulenovic, R.; Laurien, E.

2013-01-01

In case of a severe accident in a nuclear power plant meltdown of the reactor core can occur and form a packed bed in the lower plenum of the reactor pressure vessel (RPV) after solidification due to contact with water. The removal of after-heat and the long-term coolability is of essential interest. The efficient injection of cooling water into the packed bed has to be assured without endangering the structural integrity of the reactor pressure vessel. The experiments performed aimed to study the dry-out and the quenching (flooding) of hot dry packed beds. Two different inflow variants, bottom- and top-flooding including the variation of the starting temperature of the packed bed and the injection rate were studied. In case of bottom flooding the quenching time increases with increasing packed bed temperature and decreasing injection rate. In case of top flooding the flow pattern is more complex, in a first phase the water flows preferentially toward the RPV wall, the flow paths conduct the water downwards. The flow resistance of the packed bed increases with increasing bed temperatures. The quenching temperatures increase significantly above average.

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills.

Science.gov (United States)

Keshavarzi, Alireza; Noori, Lila Khaje

2010-12-01

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width [r/w]. The experimental results indicated that the convex pattern with r/w=0.35 produced minimum bed scouring depth at the center line whereas the concave pattern with r/w=0.23 produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.

Experimental Research on the Specific Energy Consumption of Rock Breakage Using Different Waterjet-Assisted Cutting Heads

Directory of Open Access Journals (Sweden)

Hongxiang Jiang

2018-01-01

Full Text Available To investigate the specific energy consumption (SE of rock breakage by cutting heads assisted by different types of waterjet and to identify optimal waterjet parameters and assistance types, rock cutting with and without waterjets was carried on a rock fragmentation test bed. SE is a comprehensive evaluation index and was developed according to the applied load on cutting head, and the SE under different cutting conditions was compared and analyzed. The results show that the SE of rock breakage without waterjet assistance increased with the increasing of rock compressive strength (RCS but that the limited drilling depth decreased. The effect of the waterjet pressure on the SE of rock breakage by the cutting head I was marked, and SE decreased by 30∼40% when the ratio between RCS and waterjet pressure was less than 1. However, the function of the waterjet assistance was poor; therefore, a ratio of 1 could be used to distinguish the rock breakage effect of cutting head I. For cutting head II, the rock damage from the waterjet impact was limited due to the large waterjet standoff distance; thus the rock breakage performance of cutting head II was also limited. The waterjet impacting at the tip of the conical pick using cutting head III could enter into the cracks caused by the mechanical pick and fracture the rock. Therefore, the rock breakage performance of cutting head III was better than that of cutting head II.

Risk factors for QTc interval prolongation

NARCIS (Netherlands)

Heemskerk, Charlotte P.M.; Pereboom, Marieke; van Stralen, Karlijn; Berger, Florine A.; van den Bemt, Patricia M.L.A.; Kuijper, Aaf F.M.; van der Hoeven, Ruud T M; Mantel-Teeuwisse, Aukje K.; Becker, Matthijs L

2018-01-01

Purpose: Prolongation of the QTc interval may result in Torsade de Pointes, a ventricular arrhythmia. Numerous risk factors for QTc interval prolongation have been described, including the use of certain drugs. In clinical practice, there is much debate about the management of the risks involved. In

The effect of bed non-uniformities and porosity of particles on dryout in boiling particle beds

International Nuclear Information System (INIS)

Macbeth, R.V.; Mogford, D.J.; Willshire, S.J.

1988-03-01

This report relates to an on-going experimental programme concerned with the coolability of beds of reactor core debris or rubble immersed in a liquid coolant, as might occur in an accident situation. The objectives are to develop experimental techniques, improve the understanding of bed cooling mechanisms, determine dry-out limitations of various bed configurations and particle shapes and sizes and devise ways of improving bed coolability. The report concentrates on a recently discovered effect on bed coolability of particle porosity, such as exists in fragmented UO 2 fuel pellets. It is shown that porosity can lower bed dry-out powers by a factor of 4 or 5. A mechanism which explains the effect is presented. The report also gives results of bed non-uniformities obtained by mixing glass particles with the dielectrically heated 'ferrite' particles used in the experiments. (author)

Core cooling and thermal responses during whole-head, facial, and dorsal immersion in 17 degrees C water.

Science.gov (United States)

Pretorius, Thea; Gagnon, Dominique D; Giesbrecht, Gordon G

2010-10-01

This study isolated the effects of dorsal, facial, and whole-head immersion in 17 degrees C water on peripheral vasoconstriction and the rate of body core cooling. Seven male subjects were studied in thermoneutral air (approximately 28 degrees C). On 3 separate days, they lay prone or supine on a bed with their heads inserted through the side of an adjustable immersion tank. Following 10 min of baseline measurements, the water level was raised such that the water immersed the dorsum, face, or whole head, with the immersion period lasting 60 min. During the first 30 min, the core (esophageal) cooling rate increased from dorsum (0.29 ± 0.2 degrees C h-1) to face (0.47 ± 0.1 degrees C h-1) to whole head (0.69 ± 0.2 degrees C h(-1)) (p whole-head immersion (114 ± 52% h(-1)) than in either facial (51 ± 47% h-1) or dorsal (41 ± 55% h(-1)) immersion (p whole-head (120.5 ± 13 kJ), facial (86.8 ± 17 kJ), and dorsal (46.0 ± 11 kJ) immersion (p whole head elicited a higher rate of vasoconstriction, the face did not elicit more vasoconstriction than the dorsum. Rather, the progressive increase in core cooling from dorsal to facial to whole-head immersion simply correlates with increased heat loss.

A graphical user interface (GUI) toolkit for the calculation of three-dimensional (3D) multi-phase biological effective dose (BED) distributions including statistical analyses.

Science.gov (United States)

Kauweloa, Kevin I; Gutierrez, Alonso N; Stathakis, Sotirios; Papanikolaou, Niko; Mavroidis, Panayiotis

2016-07-01

A toolkit has been developed for calculating the 3-dimensional biological effective dose (BED) distributions in multi-phase, external beam radiotherapy treatments such as those applied in liver stereotactic body radiation therapy (SBRT) and in multi-prescription treatments. This toolkit also provides a wide range of statistical results related to dose and BED distributions. MATLAB 2010a, version 7.10 was used to create this GUI toolkit. The input data consist of the dose distribution matrices, organ contour coordinates, and treatment planning parameters from the treatment planning system (TPS). The toolkit has the capability of calculating the multi-phase BED distributions using different formulas (denoted as true and approximate). Following the calculations of the BED distributions, the dose and BED distributions can be viewed in different projections (e.g. coronal, sagittal and transverse). The different elements of this toolkit are presented and the important steps for the execution of its calculations are illustrated. The toolkit is applied on brain, head & neck and prostate cancer patients, who received primary and boost phases in order to demonstrate its capability in calculating BED distributions, as well as measuring the inaccuracy and imprecision of the approximate BED distributions. Finally, the clinical situations in which the use of the present toolkit would have a significant clinical impact are indicated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Prolongation of islet allograft survival

International Nuclear Information System (INIS)

Lacy, P.E.; Davie, J.M.; Finke, E.H.; Scharp, D.W.

1979-01-01

Pretreatment of donor rats with irradiation and silica followed by in vitro culture of the islets for 1 to 2 days prolonged survival of allografts across a minor histocompatibility barrier if hand-picked, clean islets were used for transplantation. Pretreatment of donor rats with irradiation and silica in conjunction with a single injection of antilymphocyte serum (ALS) into the recipient produced a prolongation of survival of hand-picked islets transplanted across a major histocompatibility barrier

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations.

Science.gov (United States)

Thurtell, M J; Black, R A; Halmagyi, G M; Curthoys, I S; Aw, S T

1999-05-01

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations. The effect of vertical eye-in-head position on the compensatory eye rotation response to passive and active high acceleration yaw head rotations was examined in eight normal human subjects. The stimuli consisted of brief, low amplitude (15-25 degrees ), high acceleration (4,000-6,000 degrees /s2) yaw head rotations with respect to the trunk (peak velocity was 150-350 degrees /s). Eye and head rotations were recorded in three-dimensional space using the magnetic search coil technique. The input-output kinematics of the three-dimensional vestibuloocular reflex (VOR) were assessed by finding the difference between the inverted eye velocity vector and the head velocity vector (both referenced to a head-fixed coordinate system) as a time series. During passive head impulses, the head and eye velocity axes aligned well with each other for the first 47 ms after the onset of the stimulus, regardless of vertical eye-in-head position. After the initial 47-ms period, the degree of alignment of the eye and head velocity axes was modulated by vertical eye-in-head position. When fixation was on a target 20 degrees up, the eye and head velocity axes remained well aligned with each other. However, when fixation was on targets at 0 and 20 degrees down, the eye velocity axis tilted forward relative to the head velocity axis. During active head impulses, the axis tilt became apparent within 5 ms of the onset of the stimulus. When fixation was on a target at 0 degrees, the velocity axes remained well aligned with each other. When fixation was on a target 20 degrees up, the eye velocity axis tilted backward, when fixation was on a target 20 degrees down, the eye velocity axis tilted forward. The findings show that the VOR compensates very well for head motion in the early part of the response to unpredictable high acceleration stimuli-the eye position- dependence of the

Clinical-dosimetric analysis of measures of dysphagia including gastrostomy-tube dependence among head and neck cancer patients treated definitively by intensity-modulated radiotherapy with concurrent chemotherapy

International Nuclear Information System (INIS)

Li, Baoqing; Chen, Allen M; Li, Dan; Lau, Derick H; Farwell, D Gregory; Luu, Quang; Rocke, David M; Newman, Kathleen; Courquin, Jean; Purdy, James A

2009-01-01

To investigate the association between dose to various anatomical structures and dysphagia among patients with head and neck cancer treated by definitive intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy. Thirty-nine patients with squamous cancer of the head and neck were treated by definitive concurrent chemotherapy and IMRT to a median dose of 70 Gy (range, 68 to 72). In each patient, a gastrostomy tube (GT) was prophylacticly placed prior to starting treatment. Prolonged GT dependence was defined as exceeding the median GT duration of 192 days. Dysphagia was scored using standardized quality-of-life instruments. Dose-volume histogram (DVH) data incorporating the superior/middle pharyngeal constrictors (SMPC), inferior pharyngeal constrictor (IPC), cricoid pharyngeal inlet (CPI), and cervical esophagus (CE) were analyzed in relation to prolonged GT dependence, dysphagia, and weight loss. At 3 months and 6 months after treatment, 87% and 44% of patients, respectively, were GT dependent. Spearman's ρ analysis identified statistical correlations (p < 0.05) between prolonged GT dependence or high grade dysphagia with IPC V65, IPC V60, IPC Dmean, and CPI Dmax. Logistic regression model showed that IPC V65 > 30%, IPC V60 > 60%, IPC Dmean > 60 Gy, and CPI Dmax > 62 Gy predicted for greater than 50% probability of prolonged GT dependence. Our analysis suggests that adhering to the following parameters may decrease the risk of prolonged GT dependence and dysphagia: IPC V65 < 15%, IPC V60 < 40%, IPC Dmean < 55 Gy, and CPI Dmax < 60 Gy

Prolonged pain and disability are common after rib fractures.

Science.gov (United States)

Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

2013-05-01

The contribution of rib fractures to prolonged pain and disability may be underappreciated and undertreated. Clinicians are traditionally taught that the pain and disability of rib fractures resolves in 6 to 8 weeks. This study was a prospective observation of 203 patients with rib fractures at a level 1 trauma center. Chest wall pain was evaluated by the McGill Pain Questionnaire (MPQ) pain rating index (PRI) and present pain intensity (PPI). Prolonged pain was defined as a PRI of 8 or more at 2 months after injury. Prolonged disability was defined as a decrease in 1 or more levels of work or functional status at 2 months after injury. Predictors of prolonged pain and disability were determined by multivariate analysis. One hundred forty-five male patients and 58 female patients with a mean injury severity score (ISS) of 20 (range, 1 to 59) had a mean of 5.4 rib fractures (range, 1 to 29). Forty-four (22%) patients had bilateral fractures, 15 (7%) had flail chest, and 92 (45%) had associated injury. One hundred eighty-seven patients were followed 2 months or more. One hundred ten (59%) patients had prolonged chest wall pain and 142 (76%) had prolonged disability. Among 111 patients with isolated rib fractures, 67 (64%) had prolonged chest wall pain and 69 (66%) had prolonged disability. MPQ PPI was predictive of prolonged pain (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4 to 2.5), and prolonged disability (OR, 2.2; 95% CI, 1.5 to 3.4). The presence of significant associated injuries was predictive of prolonged disability (OR, 5.9; 95% CI, 1.4 to 29). Prolonged chest wall pain is common, and the contribution of rib fractures to disability is greater than traditionally expected. Further investigation into more effective therapies that prevent prolonged pain and disability after rib fractures is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

Directory of Open Access Journals (Sweden)

Changlu Wang

2011-04-01

Full Text Available The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. In addition, we conducted telephone interviews to 68 pest control companies within two cities in March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F. are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts. Although international and domestic travel has increased rapidly in China over the past decade (2000–2010, there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons, hotels, or trains. One city (Shenzhen city near Hong Kong experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates. There have not been any studies or reports on bed bug insecticide

Prolonged delirium misdiagnosed as a mood disorder.

Science.gov (United States)

Cao, Fei; Salem, Haitham; Nagpal, Caesa; Teixeira, Antonio L

2017-01-01

Delirium can be conceptualized as an acute decline in cognitive function that typically lasts from hours to a few days. Prolonged delirium can also affect patients with multiple predisposing and/or precipitating factors. In clinical practice, prolonged delirium is often unrecognized, and can be misdiagnosed as other psychiatric disorders. We describe a case of a 59-year-old male presenting with behavioral and cognitive symptoms that was first misdiagnosed as a mood disorder in a general hospital setting. After prolonged delirium due to multiple factors was confirmed, the patient was treated accordingly with symptomatic management. He evolved with progressive improvement of his clinical status. Early diagnosis and management of prolonged delirium are important to improve patient prognosis and avoid iatrogenic measures.

A STUDY ON ADJUVANT HEAD CORING IN PATIENTS UNDERGOING LONGITUDINAL PANCREATICOJEJUNOSTOMY AND ITS AID IN PAIN REDUCTION IN CHRONIC PANCREATITIS

Directory of Open Access Journals (Sweden)

Sudhansu Sekhar Mohanty

2016-07-01

Full Text Available BACKGROUND The condition manifests as recurrent intractable abdominal pain. 1 This is the most important indication for surgical procedures. The pain is caused by increased pancreatic parenchymal and ductal pressure. Another cause is that chronic inflammation of the pancreas may lead to fibrosis of the peripancreatic capsule and perilobular parenchyma, which impairs local and regional blood flow, therefore causing pain through tissue ischaemia and acidosis. 2 This is the rationalisation behind adding the head coring to the decompression surgeries that had been classically in practice. METHODS This is a retrospective study. The study period spans over from January 2003 to December 2013, which is a 10-year period. Patients with intractable and non-relenting abdominal pain and a diagnosis of chronic pancreatitis with evidence of fibrosis of head of pancreas in imaging studies were included. 35 patients were randomly allocated for Head coring and LPJ by lottery method. The patients were analysed for duration of surgery, hospital stay, operative/postoperative complications and assessment of postoperative pain relief. Pain relief was assessed as complete (No analgesic required, satisfactory (Tolerable pain with normal daily activities and unsatisfactory (Hospitalisation and hampered daily activities. RESULTS Alcohol consumption (65.71% was the main cause of pancreatitis in the study group, followed by gallstones (14.28% and idiopathic (20% cause. Head coring (120 minutes takes a median operative time of 30 minutes more when done adjuvant to LPJ (90 minutes. Incidence of complications were comparable in both the surgeries. The common complications of prolonged ileus and wound infection are in the percentage of 12.5% in only LPJ and 15.78% in adjuvant head coring surgeries. Pain relief was good when the complete and satisfactory groups were compared. But there is not much of difference in unsatisfactory group comparison. CONCLUSION A 30 minutes

Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler

Directory of Open Access Journals (Sweden)

Ryabov Georgy A.

2003-01-01

Full Text Available The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 °C was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.

Bedding on geotextile mattresses: how much is needed to improve cow comfort?

Science.gov (United States)

Tucker, C B; Weary, D M

2004-09-01

The objective of our study was to evaluate how the amount of sawdust bedding on mattresses affects dairy cattle behavior and preferences. Eleven nonlactating, multiparous cows were housed individually in pens with access to 3 free stalls. Each stall was fitted with a geotextile mattress covered with either 0, 1, or 7.5 kg of kiln-dried sawdust. The experiment began with 7 d of acclimatization to all 3 stalls. Cows were then allowed access to only 1 of the 3 stalls at a time, each for 3 d (restriction phase). At the end of this restriction phase, cows were allowed free access to all 3 stalls for 3 d (free-choice phase). Time spent lying and the number of lying bouts increased significantly with the amount of bedding, from 12.3 +/- 0.53 h lying and 8.5 +/- 0.62 bouts per 24 h on bare mattresses to 13.8 +/- 0.53 h lying and 10.0 +/- 0.62 bouts per 24 h on mattresses with 7.5 kg of sawdust. In addition, the animals spent less time standing with only the front hooves in the stalls when more sawdust was present. When allowed free access to all 3 options, all 11 animals spent a majority of their time lying and standing in the 7.5-kg option. In conclusion, cows preferred mattresses bedded with 7.5 kg of sawdust, on which they spent more time lying down and less time standing with only the front hooves in stalls. These results indicate that more sawdust bedding improves cow comfort in stalls with geotextile mattresses.

Seaweed beds support more juvenile reef fish than seagrass beds in a south-western Atlantic tropical seascape

Science.gov (United States)

Eggertsen, L.; Ferreira, C. E. L.; Fontoura, L.; Kautsky, N.; Gullström, M.; Berkström, C.

2017-09-01

Seascape connectivity is regarded essential for healthy reef fish communities in tropical shallow systems. A number of reef fish species use separate adult and nursery habitats, and hence contribute to nutrient and energy transfer between habitats. Seagrass beds and mangroves often constitute important nursery habitats, with high structural complexity and protection from predation. Here, we investigated if reef fish assemblages in the tropical south-western Atlantic demonstrate ontogenetic habitat connectivity and identify possible nurseries on three reef systems along the eastern Brazilian coast. Fish were surveyed in fore reef, back reef, Halodule wrightii seagrass beds and seaweed beds. Seagrass beds contained lower abundances and species richness of fish than expected, while Sargassum-dominated seaweed beds contained significantly more juveniles than all other habitats (average juvenile fish densities: 32.6 per 40 m2 in Sargassum beds, 11.2 per 40 m2 in back reef, 10.1 per 40 m2 in fore reef, and 5.04 per 40 m2 in seagrass beds), including several species that are found in the reef habitats as adults. Species that in other regions worldwide (e.g. the Caribbean) utilise seagrass beds as nursery habitats were here instead observed in Sargassum beds or back reef habitats. Coral cover was not correlated to adult fish distribution patterns; instead, type of turf was an important variable. Connectivity, and thus pathways of nutrient transfer, seems to function differently in east Brazil compared to many tropical regions. Sargassum-dominated beds might be more important as nurseries for a larger number of fish species than seagrass beds. Due to the low abundance of structurally complex seagrass beds we suggest that seaweed beds might influence adult reef fish abundances, being essential for several keystone species of reef fish in the tropical south-western Atlantic.

Investigation of heat transfer in bed and freeboard of fluidized bed combustors

International Nuclear Information System (INIS)

Mitor, V.V.; Matsnev, V.V.; Sorokin, A.P.

1986-01-01

Experimental results for heat transfer between immersed bundles of bare tubes and fluidized beds are reported. The experimental results are obtained on industrial boilers with a bed area from 2,5 to 4 m/sup 2/ under conditions of long term operation. The bed temperature range has been 1073 0 K-1233 0 K, gas velocity between 1,8-4,5 m/s, mean particle size from 1,5 mm to 6,0 mm, freeboard furnace height of 2,3 and 5 m. The obtained data are compared with experimental results from literature

Effects of age and inactivity due to prolonged bed rest on atrophy of trunk muscles.

Science.gov (United States)

Ikezoe, Tome; Mori, Natsuko; Nakamura, Masatoshi; Ichihashi, Noriaki

2012-01-01

This study investigated the effects of age and inactivity due to being chronically bedridden on atrophy of trunk muscles. The subjects comprised 33 young women (young group) and 41 elderly women who resided in nursing homes or chronic care institutions. The elderly subjects were divided into two groups: independent elderly group who were able to perform activities of daily living involving walking independently (n = 28) and dependent elderly group who were chronically bedridden (n = 13). The thickness of the following six trunk muscles was measured by B-mode ultrasound: the rectus abdominis, external oblique, internal oblique, transversus abdominis, thoracic erector spinae (longissimus) and lumbar multifidus muscles. All muscles except for the transversus abdominis and lumbar multifidus muscles were significantly thinner in the independent elderly group compared with those in the young group. The thicknesses of all muscles in the dependent elderly group was significantly smaller than that in the young group, whereas there were no differences between the dependent elderly and independent elderly groups in the muscle thicknesses of the rectus abdominis and internal oblique muscles. In conclusion, our results suggest that: (1) age-related atrophy compared with young women was less in the deep antigravity trunk muscles than the superficial muscles in the independent elderly women; (2) atrophy associated with chronic bed rest was more marked in the antigravity muscles, such as the back and transversus abdominis.

On-line monitoring of glucose and/or lactate in a fermentation process using an expanded micro-bed flow injection analyser.

Science.gov (United States)

Nandakumar, M P; Lali, A M; Mattiasson, B

1999-01-01

A novel flow injection biosensor system for monitoring fermentation processes has been developed using an expanded micro bed as the enzyme reactor. An expanded bed reactor is capable of handling a mobile phase containing suspended matter like cells and cell debris. Thus, while the analyte is free to interact with the adsorbent, the suspended particulate matter passes through unhindered. With the use of a scaled down expanded bed in the flow injection analysis (FIA) system, it was possible to analyse samples directly from a fermentor without the pretreatment otherwise required to extract the analyte or remove the suspended cells. This technique, therefore, provides a means to determine the true concentrations of the metabolites in a fermentor, with more ease than possible with other techniques. Glucose oxidase immobilised on STREAMLINE was used to measure glucose concentration in a suspension of dead yeast cells. There was no interference from the cell particles even at high cell densities such as 15 gm dry weight per litre. The assay time was about 6 min. Accuracy and reproducibility of the system was found to be good. In another scheme, lactate oxidase was covalently coupled to STREAMLINE for expanded bed operation. With the on-line expanded micro bed FIA it was possible to follow the fermentation with Lactobacillus casei.

QT interval prolongation associated with sibutramine treatment

Science.gov (United States)

Harrison-Woolrych, Mira; Clark, David W J; Hill, Geraldine R; Rees, Mark I; Skinner, Jonathan R

2006-01-01

Aims To investigate a possible association of sibutramine with QT interval prolongation. Methods Post-marketing surveillance using prescription event monitoring in the New Zealand Intensive Medicines Monitoring Programme (IMMP) identified a case of QT prolongation and associated cardiac arrest in a patient taking sibutramine for 25 days. This patient was further investigated, including genotyping for long QT syndrome. Other IMMP case reports suggesting arrhythmias associated with sibutramine were assessed and further reports were obtained from the World Health Organisation (WHO) adverse drug reactions database. Results The index case displayed a novel mutation in a cardiac potassium channel subunit gene, KCNQ1, which is likely to prolong cardiac membrane depolarization and increase susceptibility to long QT intervals. Assessment of further IMMP reports identified five additional patients who experienced palpitations associated with syncope or presyncopal symptoms, one of whom had a QTc at the upper limit of normal. Assessment of reports from the WHO database identified three reports of QT prolongation and one fatal case of torsade de pointes in a patient also taking cisapride. Conclusions This case series suggests that sibutramine may be associated with QT prolongation and related dysrhythmias. Further studies are required, but in the meantime we would recommend that sibutramine should be avoided in patients with long QT syndrome and in patients taking other medicines that may prolong the QT interval. PMID:16542208

Preliminary Core Design Analysis of a 200MWth Pebble Bed-type VHTR

International Nuclear Information System (INIS)

Jo, Chang Keun; Noh, Jae Man

2007-01-01

This paper intends to suggest the preliminary core design analysis of a VHTR for a hydrogen production. The nuclear hydrogen system that utilizes the high temperature heat generated from the VHTR is a promising candidate for a cost effective, safe and clean supply of hydrogen in the age of hydrogen economy. Among two candidate VHTR cores, that is, a prismatic modular reactor (PMR) and a pebble bed-type reactor (PBR), we focus on the design of a 200MWth PBR (hereinafter PBR200) in this paper. Here, the 200MWth power is selected for a demonstration plant. The core configuration of the PBR200 is similar to the PBMR (Pebble Bed Modular Reactor, 400MWth) of South Africa, but the overall dimension of the reactor system is scaled-down. This paper is to suggest two candidate PBR200 cores. One is an annular core with an inner reflector (PBR200-CD1) which was presented at IWRES07, and the other is a cylindrical core without an inner reflector (PBR200-CD2)

Pulsed atmospheric fluidized bed combustion

Energy Technology Data Exchange (ETDEWEB)

1989-11-01

In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

Licence prolongations of US nuclear power plants

International Nuclear Information System (INIS)

2004-04-01

Licences of US nuclear reactors were initially attributed for a 40 years duration. However, the vast majority of the reactors can benefit of a licence prolongation for a period of 20 years maximum. This article recalls first the procedure to follow for the licence prolongation demands (safety analysis, components aging, environmental impact statement), and then it makes a status of the accepted prolongations, of the demands under examination, and of the demands that should be presented in the next 5 years. (J.S.)

Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

Science.gov (United States)

Li, Dongbing; Briens, Cedric; Berruti, Franco

2015-01-01

Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Caesarean section with vacuum extraction of the head].

Science.gov (United States)

Dimitrov, A; Pavlova, E; Krŭsteva, K; Nikolov, A

2008-01-01

The aim of the study is to investigate the benefits and the limits in using the soft cup vacuum extractor on the fetal scalp during the caesarean section. The prospective study includes 19 cases of caesarean sections (group A), with vacuum assisted delivery using the soft cup vacuum extractor on the fetal scalp (diameter 6 cm) and 25 cases (group B) of caesarean sections with usual, manual extraction of the head assisted by fundal compression. All of the patients had undergone a planned caesarean section on term in absence of uterine activity and preserved amniotic membranes. Our results doesn't show differences in the Apgar score on the first and 5-th minute in the newborns of the two groups. The duration of the scalp traction was significantly shorter (30 +/- 4 sec) in comparison to the classical manual extraction (53 +/- 21 sec). The mean duration for applying the vacuum cup was 10 sec and 25 sec for tractions. The total blood loose and total duration of the caesarean sections were shorter than in the control group. The applied traction with the vacuum cup was sufficient for head extraction and there was no need for additional fundal compression. In conclusion we consider that the extraction of the fetal head in high position in caesarean section with vacuum extractor is an easy, non traumatic and rapid method which can put away the need of rough and prolonged fundal compression and its consequences.

Uranium bed oxidation vacuum process system

International Nuclear Information System (INIS)

McLeland, H.L.

1977-01-01

Deuterium and tritium gases are occluded in uranium powder for release into neutron generator tubes. The uranium powder is contained in stainless steel bottles, termed ''beds.'' If these beds become damaged, the gases must be removed and the uranium oxidized in order not to be flammable before shipment to ERDA disposal grounds. This paper describes the system and methods designed for the controlled degassing and oxidation process. The system utilizes sputter-ion, cryo-sorption and bellows pumps for removing the gases from the heated source bed. Removing the tritium gas is complicated by the shielding effect of helium-3, a byproduct of tritium decay. This effect is minimized by incremental pressure changes, or ''batch'' processing. To prevent runaway exothermic reaction, oxidation of the uranium bed is also done incrementally, or by ''batch'' processing, rather than by continuous flow. The paper discusses in detail the helium-3 shielding effect, leak checks that must be made during processing, bed oxidation, degree of gas depletion, purity of gases sorbed from beds, radioactivity of beds, bed disposal and system renovation

Practice Hospital Bed Safety

Science.gov (United States)

... Home For Consumers Consumer Updates Practice Hospital Bed Safety Share Tweet Linkedin Pin it More sharing options ... It depends on the complexity of the bed." Safety Tips CDRH offers the following safety tips for ...

Human cardiovascular response to sympathomimetic agents during head-down bed rest: the effect of dietary sodium

Science.gov (United States)

Williams, W. J.; Stuart, C. A.; Fortney, S. M.; Pietrzyk, R. A.; Chen, Y. M.; Whitson, P. A.

1994-01-01

Changes in sympathoadrenal function and cardiovascular deconditioning have long been recognized as a feature of the physiological adaptation to microgravity. The deconditioning process, coupled with altered hydration status, is thought to significantly contribute to orthostatic intolerance upon return to Earth gravity. The cardiovascular response to stimulation by sympathomimetic agents before, during, and after exposure to simulated microgravity was determined in healthy volunteers equilibrated on normal or high sodium diets in order to further the understanding of the deconditioning process.

Particle fuel bed tests

International Nuclear Information System (INIS)

Horn, F.L.; Powell, J.R.; Savino, J.M.

1985-01-01

Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H 2 for 12 hours with no visible reaction or weight loss

Evaluation of precipitates used in strainer head loss testing: Part II. Precipitates by in situ aluminum alloy corrosion

International Nuclear Information System (INIS)

Bahn, Chi Bum; Kasza, Ken E.; Shack, William J.; Natesan, Ken; Klein, Paul

2011-01-01

Graphical abstract: Display Omitted Research highlights: → Sump strainer head loss testing to evaluate chemical effects. → Aluminum hydroxide precipitates by in situ Al alloy corrosion caused head loss. → Intermetallic particles released from Al alloy can also cause significant head loss. → When evaluating Al effect on head loss, intermetallics should be considered. - Abstract: Vertical loop head loss tests were performed with 6061 and 1100 aluminum (Al) alloy plates immersed in borated solution at pH = 9.3 at room temperature and 60 o C. The results suggest that the potential for corrosion of an Al alloy to result in increased head loss across a glass fiber bed may depend on its microstructure, i.e., the size distribution and number density of intermetallic particles that are present in Al matrix and FeSiAl ternary compounds, as well as its Al release rate. Per unit mass of Al removed from solution, the WCAP-16530 aluminum hydroxide (Al(OH) 3 ) surrogate was more effective in increasing head loss than the Al(OH) 3 precipitates formed in situ by corrosion of Al alloy. However, in choosing a representative amount of surrogate for plant specific testing, consideration should be given to the potential for additional head losses due to intermetallic particles and the apparent reduction in the effective solubility of Al(OH) 3 when intermetallic particles are present.

Pseudo Random Coins Show More Heads Than Tails

OpenAIRE

Bauke, Heiko; Mertens, Stephan

2003-01-01

Tossing a coin is the most elementary Monte Carlo experiment. In a computer the coin is replaced by a pseudo random number generator. It can be shown analytically and by exact enumerations that popular random number generators are not capable of imitating a fair coin: pseudo random coins show more heads than tails. This bias explains the empirically observed failure of some random number generators in random walk experiments. It can be traced down to the special role of the value zero in the ...

Statistical description of flume experiments on mixed-size bed-load transport and bed armoring processes

Science.gov (United States)

Chen, D.; Zhang, Y.

2008-12-01

The objective of this paper is to describe the statistical properties of experiments on non-uniform bed-load transport as well as the mechanism of bed armoring processes. Despite substantial effort made over the last two decades, the ability to compute the bed-load flux in a turbulent system remains poor. The major obstacles include the poor understanding of the formation of armor lays on bed surfaces. Such a layer is much flow-resistible than the underlying material and therefore significantly inhibits sediment transport from the reach. To study the problem, we conducted a flume study for mixed sand/gravel sediments. We observed that aggregated sediment blocks were the most common characters in armor layers - the largest sizes resist hydraulic forces, while the smaller sizes add interlocking support and prevent loss of fine material through gaps between the larger particles. Fractional transport rates with the existing of armor layers were measured with time by sediment trapping method at the end of flume. To address the intermittent and time-varying behavior of bed-load transport during bed armoring processes, we investigated the probability distribution of the fractional bed-load transport rates, and the underlying dynamic model derived from the continuous time random walk framework. Results indicate that it is critical to consider the impact of armor layers when a flow is sufficient to move some of the finer particles and yet insufficient to move all the larger particles on a channel bed.

Chaotic hydrodynamics of fluidized beds

Energy Technology Data Exchange (ETDEWEB)

Van der Stappen, M.L.M. [Unit Process and Systems Engineering, Advanced Manufacturing Technology Group, Unilever Research Laboratorium, Vlaardingen (Netherlands)

1996-12-31

The major goals of this thesis are: (1) to develop and evaluate an analysis method based on techniques from non-linear chaos theory to characterize the nonlinear hydrodynamics of gas-solids fluidized beds quantitatively; and (2) to determine the dependence of the chaotic invariants on the operating conditions and investigate how the chaos analysis method can be profitably applied to improve scale-up and design of gas-solids fluidized bed reactors. Chaos theory is introduced in chapter 2 with emphasis on analysis techniques for (experimental) time series, known from literature at the start of this work (1990-1991). In chapter 3, the testing of existing and newly developed techniques on both model and fluidized bed data is described. This leads to the development of the chaos analysis method to analyze measured pressure fluctuations time series of a fluidized bed. Following, in chapter 4, this method is tested and all choices for the parameters are evaluated. The influence of the experimental parameters and external disturbances on the measurements and analysis results is discussed and quantified. The result is a chaos measurement and analysis protocol, which is further used in this work. In chapter 5, the applications to fluidized beds are discussed. It is shown that the entropy is a good measure for the characterization of the dynamical behavior of gas-solids bubbling/slugging fluidized beds. Entropy is applied to characterize the influence of the operating conditions, to assess regime transitions and to analyze dimensionless similar beds of different scale. Quantitative design correlations that relate entropy to the operating parameters (including the bed diameter) are described. Finally, it is discussed how the results of this work might be used in scaling up the chaotic dynamics of fluidized beds. The overall conclusions and outlook from this work are presented in chapter 6. 182 refs.

Comparison of packed bed and fluidized bed membrane reactors for methane reforming

NARCIS (Netherlands)

Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

2009-01-01

In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given

Effects of bed-load movement on flow resistance over bed forms

Indian Academy of Sciences (India)

Abstract. The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250mm wide and 12·5m long with glass-sides of rectan- gular cross-section and artificial dune shaped floor that was made from Plexi-glass.

Staged fluidized-bed combustion and filter system

International Nuclear Information System (INIS)

Mei, J.S.; Halow, J.S.

1994-01-01

A staged fluidized-bed combustion and filter system are described for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste. 10 figures

Performance Evaluation of Moving Bed Bio Film Reactor in Saline Wastewater Treatment

Directory of Open Access Journals (Sweden)

M Ahmadi

2013-06-01

Full Text Available Background and purpose:Moving Bed Biofilm Reactor is an aerobic attached growth with better biofilm thickness control, lack of plugging and lower head loss. Consequently, this system is greatly used by different wastewater treatment plants. High TDS wastewater produced petrochemical, leather tanning, sea food processing, cannery, pickling and dairy industries. The aim of this study was to evaluate the performance of MBBR in saline wastewater treatment. Materials and methods: In this study, 50 percent of a cylindrical reactor with 9.5 liter occupied media with 650 m2.m-3. In the first step, hydraulic regime was evaluated and startup reactor was done by sanitary sludge. Bio film was generated with glucose as the sole carbon source in synthetic wastewater. MBBR performance evaluation was performed in 6:30 and 8:45 with saline wastewater after bio film produced on media. Results: After 83 days of passing MBBR operation with saline wastewater containing 3000-12000 mg.L-1 TDS, organic loading rate of 2.2-3.5 kg/m3.d COD removal efficiency reached 80-92%. Conclusion: Moving bed biofilm reactor is effective in organic load elimination from saline wastewater.

The timing of sediment transport down Monterey Submarine Canyon, offshore California

DEFF Research Database (Denmark)

Stevens, Thomas; Paull, C.K.; Ussler, W., III

2014-01-01

luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry...... dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL......While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated...

Down Syndrome = Sindrome de Down.

Science.gov (United States)

Pueschel, S. M.; Glasgow, R. E.

Presented both in English and Spanish, the brochure is primarily concerned with biological and developmental characteristics of the person with Down's syndrome. An emphasis is on the valuable humanizing influence these individuals have on society. Brief sections in the document discuss the delayed developmental aspects of Down's syndrome; the…

Effects of hippotherapy on posture in individuals with Down Syndrome

Directory of Open Access Journals (Sweden)

Ana Paula Espindula

Full Text Available Abstract Introduction: Individuals with Down syndrome (DS have alterations that affect the musculoskeletal system, causing abnormal patterns, and alter the morphological anatomical and mechanical axes that provide intrinsic stability to the skeleton, and can trigger misalignments and orthopedic disorders in adulthood. Objective: The objective of student to evaluate posture and postural alignment before and after the hippotherapyin individuals with DS. Methods: Posture of five individuals with DS was evaluated by the software SAPO before and after 27 sessions the hippotherapy. Data were subjected to qualitative descriptive analysis using cluster and statistical analysis with the aid of the software Sigma Stat 2.0, considering differences as statistically significant at p-value < 5%. Results: Improvements were achieved for the alignment of shoulder, head, hip, and lower limbs, in addition to decrease in kyphosis and head protrusion. Conclusion: Patients with DS demonstrated satisfactory changes in motor behavior reflected in improved static posture after treatment with hippotherapy.

SU-E-T-296: Single Field Per Day Vs. Multiple Fields Per Day and the Impact On BED in Proton Therapy Treatment

International Nuclear Information System (INIS)

Grantham, K; Wooten, H; Zhao, T; Klein, E

2014-01-01

Purpose: A common practice, in proton therapy, is to deliver a rotating subset of fields from the treatment plan for the daily fractions. This study compares the impact this practice has on the biological effective dose (BED) versus delivering all planned fields daily. Methods: For two scenarios (a phantom with a geometry approximating the anatomy of a prostate treatment with opposing lateral beams, and a clinical 3-field brain treatment), treatment plans were produced in Eclipse (Varian) to simulate delivery of one, two, and three fields per fraction. The RT-Dose file, structure set, and α/β ratios were processed using in-house MATLAB code to return a new RT-Dose file containing the BED (including a proton RBE of 1.1) which was imported back into Eclipse for analysis. Results: For targets and regions of field overlap in the treatment plan, BED is not affected by delivery regimen. In the phantom, BED in the femoral heads showed increased by 20% when a single field was used rather than two fields. In the brain treatment, the minimum BED to the left optic nerve and the pituitary gland increased by 13% and 10% respectively, for a one-field regime compared to three-fields per fraction. Comparing the two-field and threefield regimes, the optic nerve BED was not significantly affected and the minimum pituitary BED was 4% higher for two fields per day. Conclusion: Hypo-fractionation effects, in regions of non-overlap of fields, significantly increase the BED to the involved tissues by as much as 20%. Care should be taken to avoid inadvertently sacrificing plan effectiveness in the interest of reduced treatment time

Bed Bugs and Schools

Science.gov (United States)

Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

Calculation of local bed to wall heat transfer in a fluidized-bed

International Nuclear Information System (INIS)

Kilkis, B.I.

1987-01-01

Surface to bed heat transfer in a fluidized-bed largely depends upon its local and global hydrodynamical behavior including particle velocity, particle trajectory, gas velocity, and void fraction. In this study, a computer program was developed in order to calculate the local bed to wall heat transfer, by accounting for the local and global instantaneous hydrodynamics of the bed. This is accomplished by utilizing the CHEMFLUB computer program. This information at a given location is interpreted so that the most appropriate heat transfer model is utilized for each time increment. These instantaneous heat transfer coefficient for the given location. Repeating the procedure for different locations, a space average heat transfer coefficient is also calculated. This report briefly summarizes the various heat transfer models employed and gives sample computer results reporting the case study for Mickley - Trilling's experimental set-up. Comparisons with available experimental data and correlations are also provided in order to compare and evaluate the computer results

Bedform development in mixed sand-mud: The contrasting role of cohesive forces in flow and bed

Science.gov (United States)

Baas, Jaco H.; Davies, Alan G.; Malarkey, Jonathan

2013-01-01

The majority of subaqueous sediment on Earth consists of mixtures of cohesive clay and cohesionless sand and silt, but the role of cohesion on the development and stability of sedimentary bedforms is poorly understood. The results of new laboratory flume experiments on bedform development in cohesive, mixed sand-mud beds are compared with the results of previous experiments in which cohesive forces in high concentration clay flows dominated bedform development. Even though both series of mixed sand-mud experiments were conducted at similar flow velocities, the textural and structural properties of the bedforms were sufficiently different to permit the designation of key criteria for identifying bedform generation under cohesive flows against bedform generation on cohesive substrates. These criteria are essential for improving bedform size predictions in sediment transport modelling in modern sedimentary environments and for the reconstruction of depositional processes in the geological record. The current ripples developing on the cohesive, mixed sand-mud beds, with bed mud fractions of up to 18%, were significantly smaller than equivalent bedforms in noncohesive sand. Moreover, the bedform height showed a stronger inversely proportional relationship with initial bed mud fraction than the bedform wavelength. This is in contrast with the bedforms developing under the cohesive clay flows, which tend to increase in size with increasing suspended clay concentration until the flow turbulence is fully suppressed. Selective removal of clay from the mixed beds, i.e., clay winnowing, was found to be an important process, with 82-100% clay entrained into suspension after 2 h of bedform development. This winnowing process led to the development of a sand-rich armouring layer. This armouring layer is inferred to have protected the underlying mixed sand-mud from prolonged erosion, and in conjunction with strong cohesive forces in the bed may have caused the smaller size of the

Prolonged response without prolonged chemotherapy: a lesson from PCV chemotherapy in low-grade gliomas

Science.gov (United States)

Peyre, Matthieu; Cartalat-Carel, Stéphanie; Meyronet, David; Ricard, Damien; Jouvet, Anne; Pallud, Johan; Mokhtari, Karima; Guyotat, Jacques; Jouanneau, Emmanuel; Sunyach, Marie-Pierre; Frappaz, Didier; Honnorat, Jérôme; Ducray, François

2010-01-01

Previous studies with temozolomide suggest that a prolonged duration of chemotherapy is important for treating low-grade gliomas (LGGs). PCV (procarbazine, CCNU, vincristine) chemotherapy has demonstrated efficacy in treating LGGs, but this therapy cannot be used for a prolonged period because of the cumulative toxicity. The aim of the present study was to evaluate the impact of first-line PCV chemotherapy on LGGs growth kinetics. The mean tumor diameter (MTD) of 21 LGGs was measured on serial magnetic resonance images before (n=13), during, and after PCV onset (n=21). During PCV treatment, a decrease in the MTD was observed in all patients. After PCV discontinuation, an ongoing decrease in MTD was observed in 20 of the 21 patients. Median duration of the MTD decrease was 3.4 years (range, 0.8–7.7) after PCV onset and 2.7 years (range, 0–7) after the end of PCV treatment with 60% of LGGs, demonstrating an ongoing and prolonged (>2 years) response despite chemotherapy no longer being administered. According to McDonald's criteria, the rates of partial and minor responses were 5% and 38% at the end of PCV but 38% and 42% at the time of maximal MTD decrease, which occurred after a median period of 3.4 years after PCV onset. These results challenge the idea that a prolonged duration of chemotherapy is necessary for treating LGGs and raise the issue of understanding the mechanisms involved in the persistent tumor volume decrease once chemotherapy is terminated. PMID:20488959

[Skull cult. Trophy heads and tzantzas in pre-Columbian America].

Science.gov (United States)

Carod-Artal, F J

2012-07-16

The skull cult is a cultural tradition that dates back to at least Neolithic times. Its main manifestations are trophy heads, skull masks, moulded skulls and shrunken heads. The article reviews the skull cult in both pre-Columbian America and the ethnographic present from a neuro-anthropological perspective. The tradition of shaping and painting the skulls of ancestors goes back to the Indo-European Neolithic period (Natufian culture and Gobekli Tepe). In Mesoamerica, post-mortem decapitation was the first step of a mortuary treatment that resulted in a trophy head, a skull for the tzompantli or a skull mask. The lithic technology utilised by the Mesoamerican cultures meant that disarticulation had to be performed in several stages. Tzompantli is a term that refers both to a construction where the heads of victims were kept and to the actual skulls themselves. Skull masks are skulls that have been artificially modified in order to separate and decorate the facial part; they have been found in the Templo Mayor of Tenochtitlan. The existence of trophy heads is well documented by means of iconographic representations on ceramic ware and textiles belonging to the Paraca, Nazca and Huari cultures of Peru. The Mundurucu Indians of Brazil and the Shuar or Jivaroan peoples of Amazonian Ecuador have maintained this custom down to the present day. The Shuar also shrink heads (tzantzas) in a ritual process. Spanish chroniclers such as Fray Toribio de Benavente 'Motolinia' and Gaspar de Carvajal spoke of these practices. In pre-Columbian America, the tradition of decapitating warriors in order to obtain trophy heads was a wide-spread and highly developed practice.

Prenatal risk indicators of a prolonged pregnancy

DEFF Research Database (Denmark)

Olesen, Annette Wind; Westergaard, Jes Grabow; Olsen, Jørn

2006-01-01

BACKGROUND: Few prenatal risk factors of prolonged pregnancy, a pregnancy of 42 weeks or more, are known. The objective was to examine whether sociodemographic, reproductive, toxicologic, or medical health conditions were associated with the risk of prolonged pregnancy. METHODS: Data from...

Protecting Your Home from Bed Bugs

Science.gov (United States)

... your home: Inspect the luggage rack in your hotel room for bed bugs. Check secondhand furniture, beds, ... with Bed Bug Problems Discover. Accessibility EPA Administrator Budget & Performance Contracting Grants January 19, 2017 Web Snapshot ...

Prolonged hypoxia modulates platelet activating factor receptor-mediated responses by fetal ovine pulmonary vascular smooth muscle cells.

Science.gov (United States)

Renteria, Lissette S; Raj, J Usha; Ibe, Basil O

2010-12-01

Hypoxia augments PAF receptor (PAFr) binding and PAFr protein expression in venous SMC (SMC-PV). We compared effect of acute and prolonged hypoxia (pO(2)<40 torr) on PAFr-mediated responses in arterial SMC (SMC-PA) and SMC-PV. Cells were studied for 30 min (acute) or for 48 h (prolonged) hypoxia and compared to normoxic (pO(2) ~100 torr) conditions. PAF binding was quantified in fmol/10(6) cells (mean ± SEM). PAF binding in normoxia were SMC-PA, 5.2 ± 0.2 and in SMC-PV, 19.3 ± 1.1; values in acute hypoxia were SMC-PA, 7.7 ± 0.4 and in SMC-PV, 27.8 ± 1.7. Prolonged hypoxia produced 6-fold increase in binding in SMC-PA, but only 2-fold increase in SMC-PV, but binding in SMC-PV was still higher. Acute hypoxia augmented inositol phosphate release by 50% and 40% in SMC-PA and SMC-PV, respectively. During normoxia, PAFr mRNA expression by both cell types was similar, but expression in hypoxia by SMC-PA was greater. In SMC-PA, hypoxia and PAF augmented intracellular calcium flux. Re-exposure of cells to 30 min normoxia after 48 h hypoxia decreased binding by 45-60%, suggesting immediate down-regulation of hypoxia-induced PAFr-mediated effects. We speculate that re-oxygenation immediately reverses hypoxia effect probably due to oxygen tension-dependent reversibility of PAFr activation and suggest that exposure of the neonate to prolonged state of hypoxia will vilify oxygen exchange capacity of the neonatal lungs. Copyright © 2010 Elsevier Inc. All rights reserved.

Evaluation of precipitates used in strainer head loss testing. Part I. Chemically generated precipitates

International Nuclear Information System (INIS)

Bahn, Chi Bum; Kasza, Ken E.; Shack, William J.; Natesan, Ken; Klein, Paul

2009-01-01

The purpose of the current program was to evaluate the properties of chemical precipitates proposed by industry that have been used in sump strainer head loss testing. Specific precipitates that were evaluated included aluminum oxyhydroxide (AlOOH) and sodium aluminum silicate (SAS) prepared according to the procedures in WCAP-16530-NP, along with precipitates formed from injecting chemicals into the test loop according to the procedure used by one sump strainer test vendor for U.S. pressurized water reactors. The settling rates of the surrogate precipitates are strongly dependent on their particle size and are reasonably consistent with those expected from Stokes' Law or colloid aggregation models. Head loss tests showed that AlOOH and SAS surrogates are quite effective in increasing the head loss across a perforated pump inlet strainer that has an accumulated fibrous debris bed. The characteristics of aluminum hydroxide precipitate using sodium aluminate were dependent on whether it was formed in high-purity or ordinary tap water and whether excess silicate was present or not.

Late Miocene marine tephra beds : recorders of rhyolitic volcanism in North Island, New Zealand

International Nuclear Information System (INIS)

Shane, P.; Black, T.; Eggins, S.; Westgate, J.

1998-01-01

A deep-sea sequence of 72 rhyolitic tephra beds, now exposed at Mahia Peninsula in the Hawke's Bay region of the east coast, North Island, New Zealand, provides a record of Late Miocene volcanism of the Coromandel Volcanic Zone (CVZ): the precursor to large-scale explosive volcanism of the Quaternary Taupo Volcanic Zone (TVZ). The geochemical signature of the glasses in the Miocene tephra has been protected from hydrothermal alteration and prolonged subaerial exposure that have affected proximal CVZ deposits. The tephra beds are primarily eruption-driven sediment gravity flows that have been emplaced into a trench-slope basin, some 300 km from active volcanoes. Their occurrence is consistent with long-distance fluvial transport followed by a point-source discharge into the deep-sea environment, and has no implications for the paleogeographic location of the basins relative to the volcanic arc. The tephra beds are calc-alkaline rhyolites with SiO 2 contents in the range 72-78 wt% (recalculated on a volatile-free basis), and are broadly similar to glassy rocks of the CVZ. Their major oxide, trace element, and REE compositions are indistinguishable from glasses of TVZ rhyolites. The trace element and REE compositional variability in the Late Miocene tephra beds, which were erupted over an estimated duration of c. 0.5-2.4 m.y. is no greater than that of large silicic eruptives of the last 350 ka, and is suggestive of a long-lived source and/or similar magmatic processes. However, the individual tephra beds are products of discrete homogeneous magma batches. New fission track ages of the Miocene tephra beds suggest the main period of volcaniclastic deposition occurred in the interval c. 9-7 Ma. This corresponds well with the initiation of rhyolitic volcanism in the CVZ at c. 10 Ma, and a major period of caldera formation that took place to c. 7 Ma. The ages suggest a sediment accumulation rate of between 0.23 and 1.2 m/ka (av. 0.4 m/ka), and a frequency of eruption of

Computer simulation of the effect of dDAVP with saline loading on fluid balance after 24-hour head-down tilt

Science.gov (United States)

Srinivasan, R. S.; Simanonok, K. E.; Charles, J. B.

1994-01-01

Fluid loading (FL) before Shuttle reentry is a countermeasure currently in use by NASA to improve the orthostatic tolerance of astronauts during reentry and postflight. The fluid load consists of water and salt tablets equivalent to 32 oz (946 ml) of isotonic saline. However, the effectiveness of this countermeasure has been observed to decrease with the duration of spaceflight. The countermeasure's effectiveness may be improved by enhancing fluid retention using analogs of vasopressin such as lypressin (LVP) and desmopressin (dDAVP). In a computer simulation study reported previously, we attempted to assess the improvement in fluid retention obtained by the use of LVP administered before FL. The present study is concerned with the use of dDAVP. In a recent 24-hour, 6 degree head-down tilt (HDT) study involving seven men, dDAVP was found to improve orthostatic tolerance as assessed by both lower body negative pressure (LBNP) and stand tests. The treatment restored Luft's cumulative stress index (cumulative product of magnitude and duration of LBNP) to nearly pre-bedrest level. The heart rate was lower and stroke volume was marginally higher at the same LBNP levels with administration of dDAVP compared to placebo. Lower heart rates were also observed with dDAVP during stand test, despite the lower level of cardiovascular stress. These improvements were seen with only a small but significant increase in plasma volume of approximately 3 percent. This paper presents a computer simulation analysis of some of the results of this HDT study.

Dynamic change of ERPs related to selective attention to signals from left and right visual field during head-down tilt

Science.gov (United States)

Wei, Jinhe; Zhao, Lun; Van, Gongdong; Chen, Wenjuan; Ren, Wei; Duan, Ran

To study further the effect of head-down tilt(HDT) on slow positive potential in the event-related potentials(ERPs), the temporal and spatial features of visual ERPs changes during 2 hour HDT(-10 °) were compared with that during HUT(+20°) in 15 normal subjects. The stimuli were consisted of two color LED flashes appeared randomly in left or right visual field(LVF or RVF) with same probability. The subjects were asked to make switch response to target signals(T) differentially: switching to left for T in LVF and to right for T in RVF, ignoring non-target signals(N). Five sets of tests were made during HUT and HDT. ERPs were obtained from 9 locations on scalp. The mean value of the ERPs in the period from 0.32-0.55 s was taken as the amplitude of slow positive potential(P400). The main results were as follows. 1)The mean amplitude of P400 decreased during HDT which was more significant at the 2nd, 3rd and 5th set of tests; 2)spatially, the reduction of mean P400 amplitude during HDT was more significant for signals from RVF and was more significant at posterior and central brain regions than that on frontal locations. As that the positive potential probably reflects the active inhibition activity in the brain during attention process, these data provide further evidence showing that the higher brain function was affected by the simulated weightlessness and that this effect was not only transient but also with interesting spatial characteristics.

An Apparatus for Bed Material Sediment Extraction From Coarse River Beds in Large Alluvial Rivers

Science.gov (United States)

Singer, M. B.; Adam, H.; Cooper, J.; Cepello, S.

2005-12-01

Grain size distributions of bed material sediment in large alluvial rivers are required in applications ranging from habitat mapping, calibration of sediment transport models, high resolution sediment routing, and testing of existing theories of longitudinal and cross steam sediment sorting. However, characterizing bed material sediment from coarse river beds is hampered by difficulties in sediment extraction, a challenge that is generally circumvented via pebble counts on point bars, even though it is unclear whether the bulk grain size distribution of bed sediments is well represented by pebble counts on bars. We have developed and tested a boat-based sampling apparatus and methodology for extracting bulk sediment from a wide range of riverbed materials. It involves the use of a 0.4 x 0.4 x 0.2 meter stainless steel toothed sampler, called the Cooper Scooper, which is deployed from and dragged downstream by the weight of a jet boat. The design is based on that of a river anchor such that a rotating center bar connected to a rope line in the boat aligns the sampler in the downstream direction, the teeth penetrate the bed surface, and the sampler digs into the bed. The sampler is fitted with lead weights to keep it from tipping over. The force of the sampler `biting' into the bed can be felt on the rope line held by a person in the boat at which point they let out slack. The boat then motors to the spot above the embedded sampler, which is hoisted to the water surface via a system of pulleys. The Cooper Scooper is then clipped into a winch and boom assembly by which it is brought aboard. This apparatus improves upon commonly used clamshell dredge samplers, which are unable to penetrate coarse or mixed bed surfaces. The Cooper Scooper, by contrast, extracts statistically representative bed material sediment samples of up to 30 kilograms. Not surprisingly, the sampler does not perform well in very coarse or armored beds (e.g. where surface material size is on the

Radiobiological evaluation of the radiation dose as used in high-precision radiotherapy. Effect of prolonged delivery time and applicability of the linear-quadratic model

International Nuclear Information System (INIS)

Shibamoto, Yuta; Otsuka, Shinya; Iwata, Hiromitsu; Sugie, Chikao; Ogino, Hiroyuki; Tomita, Natsuo

2012-01-01

Since the dose delivery pattern in high-precision radiotherapy is different from that in conventional radiation, radiobiological assessment of the physical dose used in stereotactic irradiation and intensity-modulated radiotherapy has become necessary. In these treatments, the daily dose is usually given intermittently over a time longer than that used in conventional radiotherapy. During prolonged radiation delivery, sublethal damage repair takes place, leading to the decreased effect of radiation. This phenomenon is almost universarily observed in vitro. In in vivo tumors, however, this decrease in effect can be counterbalanced by rapid reoxygenation, which has been demonstrated in a laboratory study. Studies on reoxygenation in human tumors are warranted to better evaluate the influence of prolonged radiation delivery. Another issue related to radiosurgery and hypofractionated stereotactic radiotherapy is the mathematical model for dose evaluation and conversion. Many clinicians use the linear-quadratic (LQ) model and biologically effective dose (BED) to estimate the effects of various radiation schedules, but it has been suggested that the LQ model is not applicable to high doses per fraction. Recent experimental studies verified the inadequacy of the LQ model in converting hypofractionated doses into single doses. The LQ model overestimates the effect of high fractional doses of radiation. BED is particularly incorrect when it is used for tumor responses in vivo, since it does not take reoxygenation into account. For normal tissue responses, improved models have been proposed, but, for in vivo tumor responses, the currently available models are not satisfactory, and better ones should be proposed in future studies. (author)

Does UTI cause prolonged jaundice in otherwise well infants?

Science.gov (United States)

Chowdhury, Tanzila; Kisat, Hamudi; Tullus, Kjell

2015-07-01

The symptoms of urinary tract infections in infants are very non-specific and have historically included prolonged hyperbilirubinaemia. We studied the results of routine urine samples in 319 infants with prolonged jaundice. Convincing findings of UTI was not found in any of these children even if one of them was treated with antibiotics after four consecutive urine cultures with different bacteria. A urine culture might thus not be an appropriate investigation in a child with prolonged jaundice without any other symptoms of UTI. • The symptoms of UTI in infancy are very non-specific. • Old studies suggest that prolonged hyperbilirubinaemia is one such symptom; more modern studies give more conflicting results. What is New: • Our study could not confirm that children with prolonged jaundice have an increased risk of UTI. • Routine urine testing is thus not needed in otherwise healthy infants with prolonged jaundice.

Association of achondroplasia with Down syndrome: difficulty in prenatal diagnosis by sonographic and 3-D helical computed tomographic analyses.

Science.gov (United States)

Kaga, Akimune; Murotsuki, Jun; Kamimura, Miki; Kimura, Masato; Saito-Hakoda, Akiko; Kanno, Junko; Hoshi, Kazuhiko; Kure, Shigeo; Fujiwara, Ikuma

2015-05-01

Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome. © 2014 Japanese Teratology Society.

A History of the U.S. Army Construction Engineering Research Laboratory (CERL) 1964-1985

Science.gov (United States)

1987-12-01

This practice has continued to the present. Occasionally, the Corps’ applied research would trickle down to the general public, as in the case of...of this invention when applied to the construction of pipelines, nuclear reactors , and structures in general. 7 3 The ceramic anodes represented a...installation conditions - high fills shallow cover, various bedding , and back fill conditions. 2. Standard Design of Head Walls, End Walls and Wing

Potencial evocado auditivo tardio relacionado a eventos (P300 na síndrome de Down Late auditory event-related evoked potential (P300 in Down's syndrome patients

Directory of Open Access Journals (Sweden)

Carla Patrícia Hernandez Alves Ribeiro César

2010-04-01

Full Text Available A síndrome de Down é causada pela trissomia do cromossomo 21 e está associada com alteração do processamento auditivo, distúrbio de aprendizagem e, provavelmente, início precoce de Doença de Alzheimer. OBJETIVO: Avaliar as latências e amplitudes do potencial evocado auditivo tardio relacionado a eventos (P300 e suas alterações em indivíduos jovens adultos com síndrome de Down. MATERIAL E MÉTODO: Estudo de caso prospectivo. Latências e amplitudes do P300 foram avaliadas em 17 indivíduos com síndrome de Down e 34 indivíduos sadios. RESULTADOS: Foram identificadas latências do P300 (N1, P2, N2 e P3 prolongadas e amplitude N2 - P3 diminuída nos indivíduos com síndrome de Down quando comparados ao grupo controle. CONCLUSÃO: Em indivíduos jovens adultos com síndrome de Down ocorre aumento das latências N1, P2, N2 e P3, e diminuição significativa da amplitude N2-P3 do potencial evocado auditivo tardio relacionado a eventos (P300, sugerindo prejuízo da integração da área de associação auditiva com as áreas corticais e subcorticais do sistema nervoso central.Down syndrome is caused by a trisomy of chromosome 21 and is associated with central auditory processing deficit, learning disability and, probably, early-onset Alzheimer's disease. AIM: to evaluate the latencies and amplitudes of evoked late auditory potential related to P300 events and their changes in young adults with Down's syndrome. MATERIALS AND METHODS: Prospective case study. P300 test latency and amplitudes were evaluated in 17 individuals with Down's syndrome and 34 healthy individuals. RESULTS The P300 latency (N1, P2, N2 and P3 was longer and the N2-P3 amplitude was lower in individuals with Down syndrome when compared to those in the control group. CONCLUSION: In young adults with Down syndrome, N1, P2, N2 and P3 latencies of late auditory evoked potential related to P300 events were prolonged, and N2 - P3 amplitudes were significantly reduced

Apparatus and process for controlling fluidized beds

Science.gov (United States)

Rehmat, Amirali G.; Patel, Jitendra G.

1985-10-01

An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

Heads Up

Science.gov (United States)

... Connect with Us HEADS UP Apps Reshaping the Culture Around Concussion in Sports Get HEADS UP on Your Web Site Concussion ... HEADS UP on your web site! Create a culture of safety for young athletes Officials, learn how you can ... UP to Providers HEADS UP to Youth Sports HEADS UP to School Sports HEADS UP to ...

Experimental and clinical stuties on microcirculation disturbance in the hormonal avascular necrosis of femoral head

International Nuclear Information System (INIS)

Shen Xiaowen

2007-01-01

Objective: To find the correlation factors with microcirculation disturbance by animal and clinic exprements; making clear of the pathogenetic mechanism; and providing theoritical evidence for prevention and treatment of the disease. Methods: The rabbits femoral head avascular necrosis models were induced and created by corticoid steroids. The microcirculation including capillary blood flow rate, blood viscosity, blood ingredients and histopathologic change were studied comparatively between the experimental and the control groups in order to explore the correlative factors of the incidence and proper clinical treatment. Results: The expremental group showed intracappillary blood cells aggregation, obviously slow down of blood flow, increase of serum cholesterol and protein, together with decrease of femoral head capillary vasculation. The effective rate for hormone induced femoral head avaseular necrosis through anticoagulation and promotion of microvascular circulation reached 93.75%. Conclusion: Hormone induced femoral head avascular necrosis is a kind of microcirculation disturbance disease. (authors)

Fluidized bed boiler feed system

Science.gov (United States)

Jones, Brian C.

1981-01-01

A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

Architecture of top down, parallel pattern recognition system TOPS and its application to the MR head images

International Nuclear Information System (INIS)

Matsunoshita, Jun-ichi; Akamatsu, Shigeo; Yamamoto, Shinji.

1993-01-01

This paper describes about the system architecture of a new image recognition system TOPS (top-down parallel pattern recognition system), and its application to the automatic extraction of brain organs (cerebrum, cerebellum, brain stem) from 3D-MRI images. Main concepts of TOPS are as follows: (1) TOPS is the top-down type recognition system, which allows parallel models in each level of hierarchy structure. (2) TOPS allows parallel image processing algorithms for one purpose (for example, for extraction of one special organ). This results in multiple candidates for one purpose, and judgment to get unique solution for it will be made at upper level of hierarchy structure. (author)

Fluidized bed incinerator development

International Nuclear Information System (INIS)

Ziegler, D.L.; Johnson, A.J.

1976-01-01

A fluidized bed incinerator is being developed for burning rad contaminated solid and liquid waste materials. In situ neutralization of acid gases by the bed material, catalytic afterburning, and gas filtration are used to produce a clean flue gas without the use of aqueous scrubbing

Petrology and geochemistry of samples from bed-contact zones in Tunnel Bed 5, U12g-Tunnel, Nevada Test Site

International Nuclear Information System (INIS)

Connolly, J.R.; Keil, K.; Mansker, W.L.; Allen, C.C.; Husler, J.; Lowy, R.; Fortney, D.R.; Lappin, A.R.

1984-10-01

This report summarizes the detailed geologic characterization of samples of bed-contact zones and surrounding nonwelded bedded tuffs, both within Tunnel Bed 5, that are exposed in the G-Tunnel complex beneath Rainier Mesa on the Nevada Test Site (NTS). Original planning studies treated the bed-contact zones in Tunnel Bed 5 as simple planar surfaces of relatively high permeability. Detailed characterization, however, indicates that these zones have a finite thickness, are depositional in origin, vary considerably over short vertical and horizontal distances, and are internally complex. Fluid flow in a sequence of nonwelded zeolitized ash-flow or bedded tuffs and thin intervening reworked zones appears to be a porous-medium phenomenon, regardless of the presence of layering. There are no consistent differences in either bulk composition or detailed mineralogy between bedded tuffs and bed-contact zones in Tunnel Bed 5. Although the original bulk composition of Tunnel Bed 5 was probably peralkaline, extensive zeolitization has resulted in a present peraluminous bulk composition of both bedded tuffs and bed-contact zones. The major zeolite present, clinoptilolite, is intermediate (Ca:K:Na = 26:35:39) and effectively uniform in composition. This composition is similar to that of clinoptilolite from the tuffaceous beds of Calico Hills above the static water level in hole USW G-1, but somewhat different from that reported for zeolites from below the static water level in USW G-2. Tunnel Bed 5 also contains abundant hydrous manganese oxides. The similarity in composition of the clinoptilolites from Tunnel Bed 5 and those above the static water level at Yucca Mountain indicates that many of the results of nuclide-migration experiments in Tunnel Bed 5 would be transferrable to zeolitized nonwelded tuffs above the static water level at Yucca Mountain

The effect of household heads training about the use of treated bed nets on the burden of malaria and anaemia in under-five children: a cluster randomized trial in Ethiopia

Directory of Open Access Journals (Sweden)

Deribew Amare

2012-01-01

Full Text Available Abstract Background Long-lasting insecticide-treated bed nets (LLITN have demonstrated a significant effect in reducing malaria-related morbidity and mortality. However, barriers on the utilization of LLITN have hampered the desired outcomes. The aim of this study was to assess the effect of community empowerment on the burden of malaria and anaemia in under-five children in Ethiopia. Methods A cluster randomized trial was done in 22 (11 intervention and 11 control villages in south-west Ethiopia. The intervention consisted of tailored training of household heads about the proper use of LLITN and community network system. The burden of malaria and anaemia in under-five children was determined through mass blood investigation at baseline, six and 12 months of the project period. Cases of malaria and anaemia were treated based on the national protocol. The burden of malaria and anaemia between the intervention and control villages was compared using the complex logistic regression model by taking into account the clustering effect. Eight Focus group discussions were conducted to complement the quantitative findings. Results A total of 2,105 household heads received the intervention and the prevalence of malaria and anaemia was assessed among 2410, 2037 and 2612 under-five children at baseline, six and 12 months of the project period respectively. During the high transmission/epidemic season, children in the intervention arm were less likely to have malaria as compared to children in the control arm (OR = 0.42; 95%CI: 0.32, 0.57. Symptomatic malaria also steadily declined in the intervention villages compared to the control villages in the follow up periods. Children in the intervention arm were less likely to be anaemic compared to those in the control arm both at the high (OR = 0.84; 95%CI: 0.71, 0.99 and low (OR = 0.73; 95%CI: 0.60, 0.89 transmission seasons. Conclusion Training of household heads on the utilization of LLITN significantly

Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

NARCIS (Netherlands)

Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

2010-01-01

In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

Prolonged labour as indication for emergency caesarean section

DEFF Research Database (Denmark)

Maaløe, Nanna; Sorensen, B L; Onesmo, R

2012-01-01

To audit the quality of obstetric management preceding emergency caesarean sections for prolonged labour.......To audit the quality of obstetric management preceding emergency caesarean sections for prolonged labour....

Prolonged Pregnancy: Methods, Causal Determinants and Outcome

DEFF Research Database (Denmark)

Olesen, Annette Wind

) to study the incidence of prolonged pregnancy as a function of methods for determining gestational age; 2) to determine the risk of obstetrical and fetal complications in prolonged pregnancy; 3) to validate the self-reported gestational age in the National Birth Cohort; 4) to determine whether...... an ultrasound scan in the first or second trimester, or menstrual history was best at predicting the day of delivery; 5) to study the risk of recurrence of prolonged pregnancy as a function of change in male partner, social status and municipality; and 6) to detect prenatal risk indicators of prolonged...... of perinatal and obstetrical complications was high in post-term delivery compared to term delivery (OR between 1.2 and 3.1). The risk of perinatal death (OR=1.36 (1.08-1.72)) was also higher in the post-term group (I). The self-reported gestational ages in the National Birth Cohort correlated well with data...

Early Mucosal Reactions During and After Head-and-Neck Radiotherapy: Dependence of Treatment Tolerance on Radiation Dose and Schedule Duration

International Nuclear Information System (INIS)

Fenwick, John D.; Lawrence, Geoff P.; Malik, Zafar; Nahum, Alan E.; Mayles, W. Philip M.

2008-01-01

Purpose: To more precisely localize the dose-time boundary between head-and-neck radiotherapy schedules inducing tolerable and intolerable early mucosal reactions. Methods and Materials: Total cell-kill biologically effective doses (BED CK ) have been calculated for 84 schedules, including incomplete repair effects, but making no other corrections for the effect of schedule duration T. [BED CK ,T] scatterplots are graphed, overlying BED CKboundary (T) curves on the plots and using discriminant analysis to optimize BED CKboundary (T) to best represent the boundary between the tolerable and intolerable schedules. Results: More overlap than expected is seen between the tolerable and intolerable treatments in the 84-schedule [BED CK ,T] scatterplot, but this was largely eliminated by removing gap and tolerated accelerating schedules from the plot. For the remaining 57 predominantly regular schedules, the BED CKboundary (T) boundary increases with increasing T (p = 0.0001), curving upwards significantly nonlinearly (p = 0.00007) and continuing to curve beyond 15 days (p = 0.035). The regular schedule BED CKboundary (T) boundary does not describe tolerability well for accelerating schedules (p = 0.002), with several tolerated accelerating schedules lying above the boundary where regular schedules would be intolerable. Gap schedule tolerability also is not adequately described by the regular schedule boundary (p = 0.04), although no systematic offset exists between the regular boundary and the overall gap schedule tolerability pattern. Conclusions: All schedules analyzed (regular, gap, and accelerating) with BED CK values below BED CKboundary (T)=69.5x(T/32.2)/sin((T/32.2) (radians) )-3.5Gy 10 (forT≤50 days) are tolerable, and many lying above the boundary are intolerable. The accelerating schedules analyzed were tolerated better overall than are the regular schedules with similar [BED CK ,T] values.

Effect of a Central Graphite Column on a Pebble Flow in a Pebble Bed Core

International Nuclear Information System (INIS)

In, W. K.; Lee, W. J.; Chang, J. H.

2006-01-01

A pebble bed reactor(PBR) uses coated fuel particles embedded in spherical graphite fuel pebbles. The fuel pebbles flow down through the core during an operation. The pebble bed core is configured as cylindrical or annular depending on the reactor power. It is well known that an annular core can increase a cores' thermal power. The annular inner core zone is typically filled with movable graphite balls or a fixed graphite column. The first problem with this conventional annular core is that it is difficult to maintain a boundary between the central graphite ball zone and the outer fuel zone. The second problem is that it is expensive to replace the central fixed graphite column after several tens of years of reactor operation. In order to resolve these problems, a PBR with a central graphite column in a low core is invented. This paper presents the effect of the central graphite column on a pebble flow by using the computational fluid dynamics(CFD) code, CFX-10

Fluid-bed process for SYNROC production

International Nuclear Information System (INIS)

Ackerman, F.J.; Grens, J.Z.; Ryerson, F.J.; Hoenig, C.L.; Bazan, F.; Peters, P.E.; Smith, R.; Campbell, J.H.

1983-01-01

SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates

Clinical evaluation of an automated turning bed.

Science.gov (United States)

Melland, H I; Langemo, D; Hanson, D; Olson, B; Hunter, S

1999-01-01

The purposes of this study were to assess client comfort and sleep quality, client physiologic response (skin and respiratory status), the effect on the need for caregiver assistance, and cost when using an automated turning bed. Nonexperimental, evaluative study. Twenty-four adult home or long-term care resident subjects who had a degenerative disease, spinal cord injury, stroke, cerebral palsy, or back surgery. Each subject agreed to use the automated turning bed for four weeks. Researchers completed a demographic survey and skin assessment, and assessed each subject for pressure ulcer risk and for the need of assistance of a care giver for turning before and after the four weeks of using the turning bed. Subjects rated the turning bed in terms of comfort and sleep quality. Subjects rated the turning bed as more comfortable than their own bed and expressed satisfaction at the pain relief attained when on the turning bed. While using the turning bed, there was a significant improvement in sleep quality. No skin breakdown or deterioration in respiratory status occurred. Fewer subjects required the assistance of a caregiver for turning when on the turning bed. This automated turning bed shows great promise in meeting a need for patients with limited mobility whether they are homebound or in a residential community. Future studies that further investigate use of the turning bed for postoperative back patients while still in the acute care setting are indicated. Replicative studies with a larger sample size are also indicated.

The mechanics of head-supported load carriage by Nepalese porters.

OpenAIRE

Bastien, Guillaume; Willems, Patrick; Schepens, Bénédicte; Heglund, Norman

2016-01-01

In the Everest valley of Nepal, because of the rugged mountain terrain, roads are nothing more than dirt paths and all material must be conveyed on foot. The Nepalese porters routinely carry head-supported loads, which often exceed their body mass, over long distances up and down the steep mountain footpaths. In Africa, women transport their loads economically thanks to an energy-saving gait adaptation. We hypothesized that the Nepalese porters may have developed a corresponding mechanism. To...

Predicting fractional bed load transport rates: Application of the Wilcock‐Crowe equations to a regulated gravel bed river

Science.gov (United States)

Gaeuman, David; Andrews, E.D.; Krause, Andreas; Smith, Wes

2009-01-01

Bed load samples from four locations in the Trinity River of northern California are analyzed to evaluate the performance of the Wilcock‐Crowe bed load transport equations for predicting fractional bed load transport rates. Bed surface particles become smaller and the fraction of sand on the bed increases with distance downstream from Lewiston Dam. The dimensionless reference shear stress for the mean bed particle size (τ*rm) is largest near the dam, but varies relatively little between the more downstream locations. The relation between τ*rm and the reference shear stresses for other size fractions is constant across all locations. Total bed load transport rates predicted with the Wilcock‐Crowe equations are within a factor of 2 of sampled transport rates for 68% of all samples. The Wilcock‐Crowe equations nonetheless consistently under‐predict the transport of particles larger than 128 mm, frequently by more than an order of magnitude. Accurate prediction of the transport rates of the largest particles is important for models in which the evolution of the surface grain size distribution determines subsequent bed load transport rates. Values of τ*rm estimated from bed load samples are up to 50% larger than those predicted with the Wilcock‐Crowe equations, and sampled bed load transport approximates equal mobility across a wider range of grain sizes than is implied by the equations. Modifications to the Wilcock‐Crowe equation for determining τ*rm and the hiding function used to scale τ*rm to other grain size fractions are proposed to achieve the best fit to observed bed load transport in the Trinity River.

Prolonged QRS Widening After Aripiprazole Overdose.

Science.gov (United States)

Mazer-Amirshahi, Maryann; Porter, Robert; Dewey, Kayla

2018-05-05

Aripiprazole is an atypical antipsychotic with a long half-life. Overdose can result in protracted somnolence and cardiac disturbances, particularly QT interval prolongation. This is a single case report of a 14-year-old boy who took an overdose of aripiprazole and developed QRS widening. A 14-year-old boy intentionally ingested 20 tablets of aripiprazole (5 mg). He was brought to the emergency department when his ingestion was discovered. The patient's vital signs were as follows: temperature, 37.7°C; heart rate, 108 beats/min; blood pressure, 138/98 mm Hg; and respirations, 16 breaths/min. Activated charcoal was administered within 90 minutes of ingestion. Initial electrocardiogram (EKG) showed sinus tachycardia, with a QRS of 138 ms and QT interval of 444 ms. QRS duration was 90 ms on an EKG performed 3 months earlier. A bolus of sodium bicarbonate was administered, and the patient was transferred to the pediatric intensive care unit. Repeat EKG demonstrated a QRS of 156 ms, and a sodium bicarbonate infusion was initiated. The patient continued to have QRS prolongation for the next 8 days, reaching a peak of 172 ms 3 days postingestion. Despite aggressive treatment with sodium bicarbonate, there was persistent QRS prolongation; however, the patient did not have any dysrhythmias and remained hemodynamically stable. The patient was discharged 9 days postingestion when the QRS duration normalized to 82 ms. Genetic testing revealed that the patient was a CYP2D6 poor metabolizer. This case suggests that aripiprazole toxicity may possibly be associated with QRS prolongation without associated dysrhythmias or cardiovascular compromise. In addition, toxicity may be prolonged in patients who are CYP2D6 poor metabolizers.

DNA profiling of trace DNA recovered from bedding.

Science.gov (United States)

Petricevic, Susan F; Bright, Jo-Anne; Cockerton, Sarah L

2006-05-25

Trace DNA is often detected on handled items and worn clothing examined in forensic laboratories. In this study, the potential transfer of trace DNA to bedding by normal contact, when an individual sleeps in a bed, is examined. Volunteers slept one night on a new, lower bed sheet in their own bed and one night in a bed foreign to them. Samples from the sheets were collected and analysed by DNA profiling. The results indicate that the DNA profile of an individual can be obtained from bedding after one night of sleeping in a bed. The DNA profile of the owner of the bed could also be detected in the foreign bed experiments. Since mixed DNA profiles can be obtained from trace DNA on bedding, caution should be exercised when drawing conclusions from DNA profiling results obtained from such samples. This transfer may have important repercussions in sexual assault investigations.

Utility of Recycled Bedding for Laboratory Rodents

OpenAIRE

Miyamoto, Toru; Li, Zhixia; Kibushi, Tomomi; Okano, Shinya; Yamasaki, Nakamichi; Kasai, Noriyuki

2009-01-01

Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this study, we examined the effects of bedding type on growth, hematologic and serum biochemical values, and organ weights of female and male mice reared on either recycled or fresh bedding from 3 to 33 wk of age. Neither growth nor physiology differed between mice housed on recycled bedding compared wi...

Bed-To-Wall Heat Transfer in a Supercritical Circulating Fluidised Bed Boiler

Directory of Open Access Journals (Sweden)

Błaszczuk Artur

2014-06-01

Full Text Available The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.

Differences in Pre and Post Vascular Patterning Within Retinas from ISS Crew Members and Head-Down Tilt (HDT) Subjects by VESGEN Analysis

Science.gov (United States)

Murray, M. C.; Vizzeri, G.; Taibbi, G.; Mason, S. S.; Young, M.; Zanello, S. B.; Parsons-Wingerter, P.

2018-01-01

Accelerated research by NASA has investigated the significant risks incurred during long-duration missions in microgravity for Space Flight-Associated Neuro-ocular Syndrome (SANS, formerly known as Visual Impairments associated with Increased Intracranial Pressure, VIIP) [1]. For our study, NASA's VESsel GENeration Analysis (VESGEN) was used to investigate the role of retinal blood vessels in the etiology of SANS/VIIP. The response of retinal vessels to microgravity was evaluated in astronaut crew members pre and post flight to the International Space Station (ISS), and compared to the response of retinal vessels in healthy volunteers to 6deg head-down tilt during 70 days of bed rest (HDTBR). For the study, we are testing the hypothesis that long-term cephalad fluid shifts resulting in ocular and visual impairments are necessarily mediated in part by retinal blood vessels, and therefore are accompanied by structural adaptations of the vessels. METHODS: Vascular patterns in the retinas of crew members and HDTBR subjects extracted from 30deg infrared (IR) Heidelberg Spectralis images collected pre/postflight and pre/post HDTBR, respectively, were analyzed by VESGEN (patent pending). VESGEN is a mature, automated software developed as a research discovery tool for progressive vascular diseases in the retina and other tissues. The multi-parametric VESGEN analysis generates maps of branching arterial and venous trees quantified by parameters such as the fractal dimension (Df, a modern measure of vascular space-filling capacity), vessel diameters, and densities of vessel length and number classified into specific branching generations according to vascular physiological branching rules. The retrospective study approved by NASA's Institutional Review Board included the analysis of bilateral retinas in eight ISS crew members monitored by routine occupational surveillance and six HDTBR subjects (NASA FARU Campaign 11, for example). The VESGEN analysis was conducted in a

Bed Load Variability and Morphology of Gravel Bed Rivers Subject to Unsteady Flow: A Laboratory Investigation

Science.gov (United States)

Redolfi, M.; Bertoldi, W.; Tubino, M.; Welber, M.

2018-02-01

Measurement and estimation of bed load transport in gravel bed rivers are highly affected by its temporal fluctuations. Such variability is primarily driven by the flow regime but is also associated with a variety of inherent channel processes, such as flow turbulence, grain entrainment, and bed forms migration. These internal and external controls often act at comparable time scales, and are therefore difficult to disentangle, thus hindering the study of bed load variability under unsteady flow regime. In this paper, we report on laboratory experiments performed in a large, mobile bed flume where typical hydromorphological conditions of gravel bed rivers were reproduced. Data from a large number of replicated runs, including triangular and square-wave hydrographs, were used to build a statistically sound description of sediment transport processes. We found that the inherent variability of bed load flux strongly depends on the sampling interval, and it is significantly higher in complex, wandering or braided channels. This variability can be filtered out by computing the mean response over the experimental replicates, which allows us to highlight two distinctive phenomena: (i) an overshooting (undershooting) response of the mean bed load flux to a sudden increase (decrease) of discharge, and (ii) a clockwise hysteresis in the sediment rating curve. We then provide an interpretation of these findings through a conceptual mathematical model, showing how both phenomena are associated with a lagging morphological adaptation to unsteady flow. Overall, this work provides basic information for evaluating, monitoring, and managing gravel transport in morphologically active rivers.

Numerical calculation of wall-to-bed heat transfer coefficients in gas-fluidized beds

NARCIS (Netherlands)

Kuipers, J.A.M.; Prins, W.; van Swaaij, W.P.M.

1992-01-01

A computer model for a hot gas-fluidized bed has been developed. The theoretical description is based on a two-fluid model (TFM) approach in which both phases are considered to be continuous and fully interpenetrating. Local wall-to-bed heat-transfer coefficients have been calculated by the

Direct measurement of the field from a magnetic recording head using an InAs Hall sensor on a contact write/read tester

International Nuclear Information System (INIS)

Gokemeijer, N.J.; Clinton, T.W.; Crawford, T.M.; Johnson, Mark

2005-01-01

At 1 Tbit/in 2 areal density magnetic recording dimensions, reliable magnetic field metrology does not exist. One technique to map the spatial profile of the magnetic field of a write head is to use a contact read/write tester. A magnetic recording head is brought into contact with a Hall sensor, and is subsequently scanned with nm resolution. For a 300 nm track width longitudinal recording head, the magnetic field of the head was mapped. Measurements include the down track field gradient and cross-track field profile and the current-field transfer curve. These results suggest this technique offers a viable write field metrology

Biomechanics-based active control of bedding support properties and its influence on sleep.

Science.gov (United States)

Van Deun, D; Verhaert, V; Willemen, T; Wuyts, J; Verbraecken, J; Exadaktylos, V; Haex, B; Vander Sloten, J

2012-01-01

Proper body support plays an import role in the recuperation of our body during sleep. Therefore, this study uses an automatically adapting bedding system that optimises spinal alignment throughout the night by altering the stiffness of eight comfort zones. The aim is to investigate the influence of such a dynamic sleep environment on objective and subjective sleep parameters. The bedding system contains 165 sensors that measure mattress indentation. It also includes eight actuators that control the comfort zones. Based on the measured mattress indentation, body movements and posture changes are detected. Control of spinal alignment is established by fitting personalized human models in the measured indentation. A total of 11 normal sleepers participated in this study. Sleep experiments were performed in a sleep laboratory where subjects slept three nights: a first night for adaptation, a reference night and an active support night (in counterbalanced order). Polysomnographic measurements were recorded during the nights, combined with questionnaires aiming at assessing subjective information. Subjective information on sleep quality, daytime quality and perceived number of awakenings shows significant improvements during the active support (ACS) night. Objective results showed a trend towards increased slow wave sleep. On the other hand, it was noticed that % N1-sleep was significantly increased during ACS night, while % N2-sleep was significantly decreased. No prolonged N1 periods were found during or immediately after steering.

VA National Bed Control System

Data.gov (United States)

Department of Veterans Affairs — The VA National Bed Control System records the levels of operating, unavailable and authorized beds at each VAMC, and it tracks requests for changes in these levels....

Tritium measurement technique using ''in-bed'' calorimetry

International Nuclear Information System (INIS)

Klein, J.E.; Mallory, M.K.; Nobile, A. Jr.

1991-01-01

One of the new technologies that has been introduced to the Savannah River Site (SRS) is the production scale use of metal hydride technology to store, pump, and compress hydrogen isotopes. For tritium stored in metal hydride storage beds, a unique relationship does not exist between the amount of tritium in the bed and the pressure-volume-temperature properties of the hydride material. Determining the amount of tritium in a hydride bed after desorbing the contents of the bed to a tank and performing pressure, volume, temperature, and composition (PVTC) measurements is not practical due to long desorption/absorption times and the inability to remove tritium ''heels'' from the metal hydride materials under normal processing conditions. To eliminate the need to remove tritium from hydride storage beds for measurement purposes, and ''in-bed'' tritium calorimetric measurement technique has been developed. The steady-state temperature rise of a gas stream flowing through a jacketed metal hydride storage bed is measured and correlated with power input to electric heaters used to simulate the radiolytic power generated by the decay of tritium to 3 He. Temperature rise results for prototype metal hydride storage beds and the effects of using different gases in the bed are shown. Linear regression results shows that for 95% confidence intervals, temperature rise measurements can be obtained in 14 hours and have an accuracy of ±1.6% of a tritium filled hydride storage bed

Down Syndrome

Science.gov (United States)

... Down syndrome increases as a woman gets older. Down syndrome cannot be cured. Early treatment programs can help improve skills. They may include ... occupational, and/or educational therapy. With support and treatment, many ... Down syndrome live happy, productive lives. NIH: National Institute of ...

Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

Science.gov (United States)

Revankar, Shripad T.

2002-11-01

The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

The timing of sediment transport down Monterey Submarine Canyon, offshore California

Science.gov (United States)

Stevens, Thomas; Paull, Charles K.; Ussler, William III; McGann, Mary; Buylaert, Jan-Pieter; Lundsten, Eve M.

2013-01-01

While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry into the canyon head while the 14C ages of benthic foraminifera record the deposition of hemipelagic sediments that bound the sand horizons. We use both single-grain and small (∼2 mm area) single-aliquot regeneration approaches on vibracore samples from fining-upward sequences at various water depths to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand (from 14C ages of benthic foraminifera in bracketing hemipelagic sediments) are interpreted as indicating that the sand does not pass through the entire canyon instantly in large individual events, but rather moves multiple times before emerging onto the fan. The increased spread in single-grain OSL dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL ages that are consistent with a sub-decadal recurrence frequency while the fining-upward sand sequences on the fan indicate that the channel is still experiencing events with a 150�

Equilibrium modeling of gasification: Gibbs free energy minimization approach and its application to spouted bed and spout-fluid bed gasifiers

International Nuclear Information System (INIS)

Jarungthammachote, S.; Dutta, A.

2008-01-01

Spouted beds have been found in many applications, one of which is gasification. In this paper, the gasification processes of conventional and modified spouted bed gasifiers were considered. The conventional spouted bed is a central jet spouted bed, while the modified spouted beds are circular split spouted bed and spout-fluid bed. The Gibbs free energy minimization method was used to predict the composition of the producer gas. The major six components, CO, CO 2 , CH 4 , H 2 O, H 2 and N 2 , were determined in the mixture of the producer gas. The results showed that the carbon conversion in the gasification process plays an important role in the model. A modified model was developed by considering the carbon conversion in the constraint equations and in the energy balance calculation. The results from the modified model showed improvements. The higher heating values (HHV) were also calculated and compared with the ones from experiments. The agreements of the calculated and experimental values of HHV, especially in the case of the circular split spouted bed and the spout-fluid bed were observed

Adult Bed-Wetting: A Concern?

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Adult bed-wetting: A concern? My 24-year-old husband has started to wet the bed at ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

Getting Rid of Bed Bugs

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... Directory Planning, Budget and Results Jobs and Internships Headquarters Offices Regional Offices Labs and Research Centers Bed ... to be careful in how you select a company. Related Information Collaborative Strategy on Bed Bugs - highlights ...

EPA-Registered Bed Bug Products

Science.gov (United States)

... rest or hide in hampers, bed frames, even furniture); Failing to treat adjacent areas where bed bugs ... to work (some pesticides, such as desiccators or growth regulators, may be very effective but take some ...

Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

AYGUN, H.

2012-05-01

Full Text Available Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL controller. The simulation results demonstrate some advantages of the proposed controller.

Estimation of blood volume difference between bilateral cerebral hemispheres by means of subtraction method

International Nuclear Information System (INIS)

Ueno, Ichiro

1983-01-01

It would be admitted that by measuring radioactivity of the head after intravenous injection of RI some information could be afforded concerning the cerebral vascular bed. After intravenous injection of sup(99m)Tc-pertechnetate (15mCi), an anterior view scintiscanning was made using a gamma camera combined with a computer system. Two ROIs of about 30 cm 2 were set bilateral symmetrically and a count rate curve of each ROI was obtained. The brain transit time (BTT) was calculated from first derivative of the initial count rate courve. As an index devoting difference between vascular bed of each hemisphere, the vascular bed difference index (VBDI) was introduced BTT and VBDI were calculated in 104 subjects including 11 normal controls. In most of brain tumor, cerebral hemorrhage, severe head injury and cerebral aneurysm BTTs were prolonged in affected hemispheres. However, in a half of cerebral infarction cases BTTs were rather shortened on the affected side. In normal controls, the absolute value of VBDI was [0.16 +- 0.06(S.D.)]. In cases of brain tumor, cerebral hemorrhage and severe head injury, VBDI showed a significant deviation from the normal range, taking plus value. This results suggest, according to the definition of VBDI, vascular beds of the affected hemisphere are abnormally decreased compared with those of non-affected side. In cases of arteriovenous malformation VBDIs were increased on the affected side, reflecting enlarged tangle of arteriols and venous vessels. On the other hand, in cases of cerebral infarction, VBDI varied from case to case, making it difficult to get some conclusion from the present data. VBDI, however, invariably decreased in cases in which the occlusion of arteries were definitely confirmed by angiography

Development of pressurized internally circulating fluidized bed combustion technology; Kaatsu naibu junkan ryudosho boiler no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ishihara, I [Center for Coal Utilization, Japan, Tokyo (Japan); Nagato, S; Toyoda, S [Ebara Corp., Tokyo (Japan)

1996-09-01

The paper introduced support research on element technology needed for the design of hot models of the pressurized internally circulating fluidized bed combustion boiler in fiscal 1995 and specifications for testing facilities of 4MWt hot models after finishing the basic plan. The support research was conduced as follows: (a) In the test for analysis of cold model fluidization, it was confirmed that each characteristic value of hot models is higher than the target value. Further, calculation parameters required for computer simulation were measured and data on the design of air diffusion nozzle for 1 chamber wind box were sampled. (b) In the CWP conveyance characteristic survey, it was confirmed that it is possible to produce CWP having favorable properties. It was also confirmed that favorable conveyability can be maintained even if the piping size was reduced down to 25A. (c) In the gas pressure reducing test, basic data required for the design of gas pressure reducing equipment were sampled. Specifications for the fluidized bed combustion boiler of hot models are as follows: evaporation amount: 3070kg/h, steam pressure: 1.77MPa, fuel supply amount: 600kg-coal/h, boiler body: cylinder shape water tube internally circulating fluidized bed combustion boiler. 4 refs., 4 figs.

Comparison of a Physical and Numerical Mobile-Bed Model of Beach and T-Head Groin Interaction

Science.gov (United States)

2011-05-01

Hydraulic Centre’s Large Area Basin (LAB), utilizing a set of moveable wave generators capable of providing long-crested waves to match a variety...was conducted manually from a bridge as shown in Figure 4. The location of the transect (Profile 2) is shown in Figure 2. Planform morphology was...4. Physical model oblique view showing profile measurement location and bridge . 2617 The T-head groins and the shore-normal breakwater trunk at the

Emergency core cooling system sump chemical effects on strainer head loss

International Nuclear Information System (INIS)

Edwards, M.K.; Qiu, L.; Guzonas, D.A.

2010-01-01

Chemical precipitates formed in the recovery water following a Loss of Coolant Accident (LOCA) have the potential to increase head loss across the Emergency Core Cooling System (ECCS) strainer, and could lead to cavitation of the ECCS pumps, pump failure and loss of core cooling. AECL, as a strainer vendor and research organization, has been involved in the investigation of chemical effects on head loss for its CANDU® and Pressurized Water Reactor (PWR) customers. The chemical constituents of the recovery sump water depend on the combination of chemistry control additives and the corrosion and dissolution products from metals, concrete, and insulation materials. Some of these dissolution and corrosion products (e.g., aluminum and calcium) may form significant quantities of precipitates. The presence of chemistry control additives such as sodium hydroxide, trisodium phosphate and boric acid can significantly influence the precipitates formed. While a number of compounds may be shown to be thermodynamically possible under the conditions assumed for precipitation, kinetic factors play a large role in the morphology of precipitates. Precipitation is also influenced by insulation debris, which can trap precipitates and act as nucleation sites for heterogeneous precipitation. This paper outlines the AECL approach to resolving the issue of chemical effects on ECCS strainer head loss, which included modeling, bench top testing and reduced-scale testing; the latter conducted using a temperature-controlled variable-flow closed-loop test rig that included an AECL Finned Strainer® test section equipped with a differential pressure transmitter. Models of corrosion product release and the effects of precipitates on head loss will also be presented. Finally, this paper discusses the precipitates found in test debris beds and presents a possible method for chemical effects head loss modeling. (author)

Expanded-bed chromatography in primary protein purification.

Science.gov (United States)

Anspach, F B; Curbelo, D; Hartmann, R; Garke, G; Deckwer, W D

1999-12-31

Chromatography in stable expanded beds enables proteins to be recovered directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids. The general performance of an expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles in the column. However, optimal operating conditions are more restricted than in a packed bed due to the dependence of bed expansion on the size and density of the adsorbent particles as well as the viscosity and density of the feedstock. The feedstock composition may become the most limiting restriction owing to interactions of adsorbent particles with cell surfaces, DNA and other substances, leading to their aggregation and consequently to bed instabilities and channeling. Despite these difficulties, expanded-bed chromatography has found widespread applications in the large scale purification of proteins from mammalian cell and microbial feedstocks in industrial bioprocessing. The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

Fluidization quality analyzer for fluidized beds

Science.gov (United States)

Daw, C.S.; Hawk, J.A.

1995-07-25

A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

High Intensity Resistive and Rowing Exercise Countermeasures Do Not Prevent Orthostatic Intolerance Following 70 Days of Bed Rest

Science.gov (United States)

Lee, Stuart M. C.; Stenger, Michael B.; Laurie, Steven S.; Ploutz-Snyder, Lori L.; Platts, Steven H.

2015-01-01

More than 60% of US astronauts participating in Mir and early International Space Station missions (greater than 5 months) were unable to complete a 10-min 80 deg head-up tilt test on landing day. This high incidence of post-spaceflight orthostatic intolerance may be related to limitations of the inflight exercise hardware that prevented high intensity training. PURPOSE: This study sought to determine if a countermeasure program that included intense lower-body resistive and rowing exercises designed to prevent cardiovascular and musculoskeletal deconditioning during 70 days of 6 deg head-down tilt bed rest (BR), a spaceflight analog, also would protect against post- BR orthostatic intolerance. METHODS: Sixteen males participated in this study and performed no exercise (Control, n=10) or performed an intense supine exercise protocol with resistive and aerobic components (Exercise, n=6). On 3 days/week, exercise subjects performed lower body resistive exercise and a 30-min continuous bout of rowing (greater than or equal to 75% max heart rate). On 3 other days/week, subjects performed only high-intensity, interval-style rowing. Orthostatic intolerance was assessed using a 15-min 80 deg head-up tilt test performed 2 days (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using a carbon monoxide rebreathing technique on BR-3 and before rising on the first recovery day (BR+0). RESULTS: Following 70 days of BR, tilt tolerance time decreased significantly in both the Control (BR-2: 15.0 +/- 0.0, BR70: 9.9 +/- 4.6 min, mean +/- SD) and Exercise (BR-2: 12.2 +/- 4.7, BR70: 4.9 +/- 1.9 min) subjects, but the decreased tilt tolerance time was not different between groups (Control: -34 +/- 31, Exercise: -56 +/- 16%). Plasma volume also decreased (Control: -0.56 +/- 0.40, Exercise: -0.48 +/- 0.33 L) from pre to post-BR, with no differences between groups (Control: -18 +/- 11%, Exerciser: -15 +/-1 0%). CONCLUSIONS: These findings confirm previous reports

Fluidised bed heat exchangers

International Nuclear Information System (INIS)

Elliott, D.E.; Healey, E.M.; Roberts, A.G.

1974-01-01

Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

Solid fuel feed system for a fluidized bed

Science.gov (United States)

Jones, Brian C.

1982-01-01

A fluidized bed for the combustion of coal, with limestone, is replenished with crushed coal from a system discharging the coal laterally from a station below the surface level of the bed. A compartment, or feed box, is mounted at one side of the bed and its interior separated from the bed by a weir plate beneath which the coal flows laterally into the bed while bed material is received into the compartment above the plate to maintain a predetermined minimum level of material in the compartment.

Visual loss and optic nerve head swelling in thiamine deficiency without prolonged dietary deficiency

Directory of Open Access Journals (Sweden)

Gratton SM

2014-05-01

Full Text Available Sean M Gratton, Byron L LamBascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, USAAbstract: Visual loss due to optic neuropathy is a rare manifestation of thiamine deficiency. We report a case of a 39-year-old woman with a body mass index (BMI of 29 kg/m2 who developed visual loss and bilateral optic nerve head swelling after a short, self-limited gastrointestinal illness. She was disoriented and inattentive and had absent ankle jerk reflexes, diminished sensation in both legs below the knees, and marked truncal ataxia. Magnetic resonance imaging (MRI showed increased T2-signal in the medial thalami and mammillary bodies. The serum thiamine level was 8 nmol/L (normal 8–30. The diagnosis of thiamine deficiency was made, and the patient’s vision and neurologic symptoms improved significantly with intramuscular thiamine treatment. Thiamine deficiency can occur in the absence of an obvious predisposing factor such as alcoholism or low body weight. The clinician must be aware of the factors that govern vitamin availability and maintain a high index of suspicion to make the diagnosis in such cases.Keywords: optic neuropathy, nutritional deficiency

Combustion of peanut shells in a cone-shaped bubbling fluidized-bed combustor using alumina as the bed material

International Nuclear Information System (INIS)

Arromdee, Porametr; Kuprianov, Vladimir I.

2012-01-01

Highlights: ► We propose burning of peanut shells in a conical fluidized bed using alumina sand. ► We examine hydrodynamic, combustion and emission characteristics of the reactor. ► High, over 99%, combustion efficiency is achievable. ► Emissions of CO and NO from the combustor meet the national emission limits. ► Composition of the bed material undergoes significant changes during the combustion. -- Abstract: This paper reports experimental studies on burning peanut shells in the conical fluidized-bed combustor using alumina sand as the fluidizing agent. Prior to combustion tests, hydrodynamic regimes and characteristics of a conical alumina–biomass bed were investigated under cold-state conditions for variable percentage of peanut shells in the mixture and static bed height. With selected particle sizes (300–500 μm) and static bed height (30 cm), alumina ensured bubbling fluidization regime of the bed at operating conditions specified for firing biomass. Combustion tests were performed at 60 kg/h and 45 kg/h fuel feed rates, while ranging excess air from 20% to 80% at a fixed combustor load. Temperature and gas concentrations (O 2 , CO, C x H y as CH 4 , and NO) were measured along radial and axial directions inside the reactor as well as at stack in order to characterize combustion and emission performance of the combustor for the ranges of operating conditions. For firing 60 kg/h peanut shells, excess air of 40% can be selected as an appropriate value ensuring high, about 99%, combustion efficiency and rather low emissions of CO and NO: 520 ppm and 125 ppm, respectively (both on a dry basis and at 6% O 2 ). With reducing combustor load, the combustion efficiency and emission characteristics were improved to a little extent. No evidence of bed agglomeration was found during 30-h combustion tests on this conical fluidized-bed combustor using alumina sand as the bed material. However, the timescale effect on the composition of the bed material was

Removal of personal care compounds from sewage sludge in reed bed container (lysimeter) studies--effects of macrophytes.

Science.gov (United States)

Chen, Xijuan; Pauly, Udo; Rehfus, Stefan; Bester, Kai

2009-10-15

Sludge reed beds have been used for dewatering (draining and evapotranspiration) and mineralisation of sludge in Europe since 1988. Although reed beds are considered as a low cost and low contamination method in reducing volume, breaking down organic matter and increasing the density of sludge, it is not yet clear whether this enhanced biological treatment is suitable for degradation of organic micro-pollutants such as personal care products. Within this project the effect of biological sludge treatment in a reed bed on reducing the concentrations of the fragrances HHCB, AHTN, OTNE was studied as on the bactericide Triclosan. Additionally, the capacity of different macrophytes species to affect the treatment process was examined. Three different macrophyte species were compared: bulrush (Typha latifolia), reed (Phragmites australis) and reed canary grass (Phalaris arundinacea). They were planted into containers (lysimeters) with a size of 1 m x 1 m x 1 m which were filled with 20 cm gravel at the bottom and 50 cm sludge on top, into which the macrophytes were planted. During the twelve months experiment reduction of 20-30% for HHCB and AHTN, 70% for Triclosan and 70% for OTNE were determined under environmental conditions. The reduction is most likely due to degradation, since volatilization, uptake into plants and leaching are insignificant. No difference between the containers with different macrophyte species or the unplanted containers was observed. Considering the usual operation time of 10 years for reed beds, an assessment was made for the whole life time.

Coolability of volumetrically heated particle beds

Energy Technology Data Exchange (ETDEWEB)

Rashid, Muhammad

2017-03-22

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al{sub 2}O{sub 3} particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m{sup 2}, polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements

Coolability of volumetrically heated particle beds

International Nuclear Information System (INIS)

Rashid, Muhammad

2017-01-01

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al 2 O 3 particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m 2 , polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements in

Flow characteristics of counter-current flow in debris bed

International Nuclear Information System (INIS)

Abe, Yutaka; Adachi, Hiromichi

2004-01-01

In the course of a severe accident, a damaged core would form a debris bed consisting of once-molten and fragmented fuel elements. It is necessary to evaluate the dryout heat flux for the judgment of the coolability of the debris bed during the severe accident. The dryout phenomena in the debris bed is dominated by the counter-current flow limitation (CCFL) in the debris bed. In this study, air-water counter-current flow behavior in the debris bed is experimentally investigated with glass particles simulating the debris beds. In this experiment, falling water flow rate and axial pressure distributions were experimentally measured. As the results, it is clarified that falling water flow rate becomes larger with the debris bed height and the pressure gradient in the upper region of the debris bed is different from that in the lower region of the debris bed. These results indicate that the dominant region for CCFL in the debris bed is identified near the top of the debris bed. Analytical results with annular flow model indicates that interfacial shear stress in the upper region of the debris bed is larger than that in the lower region of the debris bed. (author)

Fluidized-bed nuclear reactor

International Nuclear Information System (INIS)

Grimmett, E.S.; Kunze, J.F.

1975-01-01

A reactor vessel containing a fluidized-bed region of particulate material including both a neutron-moderating and a fertile substance is described. A gas flow including fissile material passes through the vessel at a sufficient rate to fluidize the particulate material and at a sufficient density to support a thermal fission reaction within the fluidized-bed region. The high-temperature portion of a heat transfer system is located within the fluidized-bed region of the reactor vessel in direct contact with the fluidized particles. Heat released by fission is thereby transferred at an enhanced rate to a coolant circulating within the heat transfer system. Fission products are continuously removed from the gas flow and supplemental fissile material added during the reactor operation. (U.S.)

Bed wise cost analysis of in-patient treatment of brachial plexus injury at a Level I trauma Center in India

OpenAIRE

Pandey, Nityanand; Gupta, Deepak; Mahapatra, Ashok; Harshvardhan, Rajesh

2014-01-01

Aim: The aim was to calculate, in monetary terms, total cost incurred by a Level I trauma center in providing in-patient care to brachial plexus injury patients during their preoperative and the postoperative stay. Subjects and Methods: All patients of brachial plexus injury admitted and discharged between January and December 2010 were included in the study. Total cost per bed was calculated under several cost heads in pre- and post-operative ward care. Intra-operative costs were excluded. R...

Lymphangioma of the head and neck: Four case reports

Energy Technology Data Exchange (ETDEWEB)

Cho, Bong Hae; Nah, Kyung Soo [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Jeong, Yeon Hwa [Dept. of Dental Hygiene, Yeojoo Institute of Technology, Yeojoo (Korea, Republic of)

2000-03-15

Lymphangiomas are uncommon benign congenital tumors. Most occur in the head and neck and most lesions present by the age of 2 years. We present our experience with four patients who have lymphangiomas of the head and neck with tongue involvement. First case is a 7-year-old male who has the cystic lymphangioma of left submandibular area. Second a 22-year-old female has a lesion involving the border of right tongue. Third case is the lymphangioma which occur in the right upper lip of a 6-year old male. The last patient is a 28-year old male who fell down and whose right face was swollen up. He had undergone an operation and treated with steroid before. The characteristic appearances of imaging methods were described and all lesions best depicted on T2-weighted images. Our experience indicates that MRI is useful in the diagnosis and treatment planning of lymphangioma.

Lymphangioma of the head and neck: Four case reports

International Nuclear Information System (INIS)

Cho, Bong Hae; Nah, Kyung Soo; Jeong, Yeon Hwa

2000-01-01

Lymphangiomas are uncommon benign congenital tumors. Most occur in the head and neck and most lesions present by the age of 2 years. We present our experience with four patients who have lymphangiomas of the head and neck with tongue involvement. First case is a 7-year-old male who has the cystic lymphangioma of left submandibular area. Second a 22-year-old female has a lesion involving the border of right tongue. Third case is the lymphangioma which occur in the right upper lip of a 6-year old male. The last patient is a 28-year old male who fell down and whose right face was swollen up. He had undergone an operation and treated with steroid before. The characteristic appearances of imaging methods were described and all lesions best depicted on T2-weighted images. Our experience indicates that MRI is useful in the diagnosis and treatment planning of lymphangioma.

Limitations due to strong head-on beam-beam interactions (MD 1434)

CERN Document Server

Buffat, Xavier; Iadarola, Giovanni; Papadopoulou, Parthena Stefania; Papaphilippou, Yannis; Pellegrini, Dario; Pojer, Mirko; Crockford, Guy; Salvachua Ferrando, Belen Maria; Trad, Georges; Barranco Garcia, Javier; Pieloni, Tatiana; Tambasco, Claudia; CERN. Geneva. ATS Department

2017-01-01

The results of an experiment aiming at probing the limitations due to strong head on beam-beam interactions are reported. It is shown that the loss rates significantly increase when moving the working point up and down the diagonal, possibly due to effects of the 10th and/or 14th order resonances. Those limitations are tighter for bunches with larger beam-beam parameters, a maximum total beam-beam tune shift just below 0.02 could be reached.

Why Does Zipf's Law Break Down in Rank-Size Distribution of Cities?

OpenAIRE

Kuninaka, Hiroto; Matsushita, Mitsugu

2008-01-01

We study rank-size distribution of cities in Japan on the basis of data analysis. From the census data after World War II, we find that the rank-size distribution of cities is composed of two parts, each of which has independent power exponent. In addition, the power exponent of the head part of the distribution changes in time and Zipf's law holds only in a restricted period. We show that Zipf's law broke down due to both of Showa and Heisei great mergers and recovered due to population grow...

Cephalometrics in children with Down's syndrome

Energy Technology Data Exchange (ETDEWEB)

Quintanilla, Juan Suarez; Biedma, Benjamin Martin; Rodriguez, Maximino Quintans; Mora, Maria Teresa Jorge; Cunqueiro, Maria Mercedes Suarez; Pazos, Mayte Abeleira [Faculty of Medicine and Dentistry, University of Santiago, San Francisco s/n, 15705 Santiago de Compostela (Spain)

2002-09-01

Heading AbstractAims. To describe the craniofacial morphology of a group of patients with Down's syndrome using a cephalometric analysis of the lateral skull radiograph.Materials and methods. The studied sample consisted of 39 patients with Down's syndrome (24 boys, 15 girls) ranging from 7 to 18 years of age. The computerized cephalometric study of the lateral skull radiograph of each patient was carried out using the method described by Ricketts.Results.Anterior cross-bite was observed in 38.4% of patients and diminished interincisal angle in 77%. Skeletal parameters matched the clinical norm, indicating mesofacial biotype, i.e., normal maxillomandibular growth. The lower incisors protruded in 84.6% of the individuals studied and were proinclined in 77%; upper incisors were protruded in 77% of the sample. The lower lip protruded in 84.6%. Analysis of craniofacial parameters showed average values within the clinical norm. Analysis of the inner cranium demonstrated normal inclination of the cranial base, while the length of the anterior skull base was diminished in 53.8%.Conclusions. From the skeletal perspective, patients with Down's syndrome who are in a period of growth demonstrate a reduction of the anterior skull base. From the dentoalveolar perspective, they show protrusion and proinclination of lower incisors, which is related to a tendency to anterior cross-bite and, to a lesser extent, to diminished overbite. Likewise, the lower lip protrusion observed in this study is related to the position of the lower incisor. (orig.)