Bed Angle Research Articles

Lateral Pressure and VAS Pain Score Analysis for the Lateral Lumbar Interbody Fusion Procedure.

The lateral lumbar interbody fusion (LLIF) procedure is a minimally invasive procedure that has become widely utilized. The LLIF procedure typically involves bending the table to access the disc spaces of interest due to anatomical constraints. It is unknown if this bending process is painful or what pressures are exhibited on the downside part of the body. The goal of the study was to determine whether sex, height, weight, body mass index, bed angle, or positioning relative to the break of the bed affects the downside skin pressures and VAS pain scores in awake volunteers. Fifty-six volunteers were placed in the lateral decubitus position and pressure sensors were placed at the downside part of their anatomy (shoulder, T10 rib , iliac crest, and greater trochanter). The pressures were checked with the iliac crest or greater trochanter at 0, 10, 20, 30, 40 degree bed angles. VAS scores were checked when the iliac crest or greater trochanter were at the maximum bed break angles. A significant positive association was found between increased bed angle and pressure at all five areas on the downside body locations (p<0.0001). The greatest pressures were located at the iliac crest and greater trochanter when these specific locations were centered over the break of the bed (p<0.0001). When the iliac crest was placed at maximal bed break, each unit increase in BMI increased the VAS pain by 0.13 (p<0.0001)and men had 1.96 (p=0.0009)higher VAS scores then women. When the greater trochanter was placed at the maximal bed break, each unit increase in BMI decreased VAS pain by 0.19 (p<0.0001) and women had 1.55 (p=0.0002)higher VAS pain scores then men. In awake volunteers, the pressure at the iliac crest or greater trochanter at the break of the bed increases by increasing the bed angle. Women with a lower BMI had high VAS pain scores when their greater trochanter was at maximal bed break. Men with higher BMI had high VAS pain scores when their iliac crest was at maximal bed break. An awareness of the iliac crest or greater trochanter at the break of the bed should be considered to prevent pain and increased pressure based on the patient's sex and BMI.

Influence of Bed Geometry on the Drying of Skimmed Milk in a Spouted Bed

In this present work, the fluidynamic and drying process of skimmed milk in conical and conical-cylindrical spouted bed was analyzed as a function of different bed geometry and operating conditions. It used three internal cone angles (45°, 60° and 75°), different loads of inert particles (1.50, 3.00 and 4.50 kg) and a fixed static bed height (20.50 cm). Polyethylene particles of 4.38 mm of diameter and 930.50 ± 0.3 kg/m3 of specific mass were used as inert particles. An artificial neural network model was trained to predict the peak pressure drop and the minimum spout velocity from an experimental data bank. The experimental results showed a significant effect of geometric characteristics of the bed on fluidynamics parameters. It was also observed for the operating conditions that conical spouted bed and cone angle of 45° were more suitable for drying skimmed milk. The neural network provided predictions in good agreement with experimental data.

Cracking, stability and slope reinforcement analysis relating to the Jinping dam based on a geomechanical model test

The aim of this study is to examine cracking and instability of the high and steep left bank slope with weak rock mass structures, and effectiveness of the reinforcements designed for the slope at the Jinping hydroelectricity power station, southwestern China. A new geomechanical model testing method is first proposed for evaluating slope safety factors. In the proposed geomechanical model test, the slope is constructed on a flat testing bed, which can be rotated by hydraulic lifts. By increasing the rotation angle of the testing bed, the forces tending to induce the sliding of the slope are increased, which may cause crack initiation and propagation in the slope and result in rock mass slippage. Thus, through the proposed geomechanical model test, the slope failure mechanism, progressive failure process and final failure pattern can be studied. Moreover, the stability safety factors can be evaluated according to displacement data monitored by sensors installed in the geomechanical model. The geomechanical model test of the Jinping left-bank slope reveals that the bending and toppling cracks occur simultaneously in the unreinforced zone of the slope together with strong relaxation and tension cracks. It is found that the factor controlling the rock mass failure and instability is the structurally weak rock mass and the dominant failure mode is the integral catastrophic instability mode, in which the slope energy is totally dissipated and the slope destabilizes at a limit state. The reinforcement installed in the large area above the elevation of the dam-slope abutment and the unloading action due to the excavation of rocks lying above the dam platform have effectively improved the anti-slide safety factor of the slope, and thus increased its inherent safety factor. On the basis of the geomechanical model testing results and their comparisons with field monitoring results, it is concluded that the installed rock bolts and long anchor reinforcement measures are very effective in keeping the cracks closed in the rock mass and maintaining the slope stability.

A study on the development of subsidence due to the extraction of 1203 slice with its associated factors around Barapukuria underground coal mining industrial area, Dinajpur, Bangladesh

Subsidence as a result of an underground coal mine is a hazard to human life, properties and environment. This incidence usually occurs over a long period of time which directly or indirectly pertinent with various factors that needs to be carefully considered and systematically analyzed when exploring land subsidence. In reality the relationships among factors, their effects and the subsidence are crucial to have the suitable management plan for the mine-induced ground subsidence around the mining area. In this research, primarily the development of subsidence caused by the extraction of 1203 slice has been evaluated under the profile functions and influence functions methods. The results show that the calculated subsidence profile is almost trough-like subsidence where the maximum amount of subsidence is about 0.89 m. Secondly, based on this result, the analysis on different factors such as the deeper coal bed (420 m depth level) and higher angle of draw (42.5o) show less subsidence which are 0.58 and 0.87 m, respectively, whereas the dip of the coal bed up to 20o does not have significant effect on subsidence. In latter cases, the different preceding scientific papers have been consulted and analyzed for recognizing various influencing factors of subsidence which replicate that the geology and stratigraphic configuration, structural setting of the coal basin, hydro-geological characteristics, less competent nature of overlying rock body, applied mining method, presence of multi-coal seams, ultra thicken coal seam and so on are the major factors in affecting the subsidence event in the area. Moreover, intensive site investigations revealed similar pattern of subsidence and its associated factors around the mine.

Head Position and Cerebral Blood Flow Velocity in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Background: Patients with acute ischemic stroke (AIS) have impaired vasomotor reactivity, especially in the affected cerebral hemisphere, such that they may depend directly on systemic blood pressure to maintain perfusion to vulnerable ‘at risk' penumbral tissue. As the sitting up position may affect cerebral perfusion by decreasing cerebral blood flow (CBF) in salvageable tissue, positioning AIS patients with their head in a lying flat position could increase CBF through collateral circulation or gravitational force. We wished to quantify the effect of different head positions on mean flow velocity (MFV) by transcranial Doppler ultrasonography (TCD) in AIS patients to assess the potential for benefit (or harm) of head positioning in a clinical trial. Methods: We performed a systematic review and meta-analysis of observational studies with TCD to evaluate differences in cerebral MFV between the lying flat and sitting up head positions in AIS. For each study and each comparison, we obtained the mean value of changes in MFV and its variance. Results: A total of 303 studies were identified, but 298 were excluded for varying reasons; 4 papers met the inclusion criteria and 57 patients were included in the meta-analysis for calculation of the overall mean difference in MFV. We found a significant increase in MFV from a bed angle of 30 to 15° (4.6 cm/s, 95% confidence interval, CI, 2.9-6.2, p < 0.001) and from 30 to 0° (8.3 cm/s, 95% CI 5.3-11.3, p < 0.001) in the affected hemisphere but not on the normal side in AIS patients. Conclusions: In AIS patients, MFV increased significantly in the side affected by the stroke but not in the unaffected side when they were positioned in a lying flat head position at 0 or 15° compared to an upright head position at 30°. The clinical significance of these findings is now undergoing further randomized evaluation in the international multicenter Head Position in Acute Stroke Trial (HeadPoST).

Geometrical characterization and performance optimization of monopropellant thruster injector

The function of the injector in a monopropellant thruster is to atomize the liquid hydrazine and to distribute it over the catalyst bed as uniformly as possible. A second objective is to place the maximum amount of catalyst in contact with the propellant in as short time as possible to minimize the starting transient time. Coverage by the spray is controlled mainly by cone angle and diameter of the catalyst bed, while atomization quality is measured by the Sauter Mean Diameter, SMD. These parameters are evaluated using empirical formulae. In this paper, two main types of injectors are investigated; plain orifice and full cone pressure swirl injectors. The performance of these two types is examined for use with blow down monopropellant propulsion system. A comprehensive characterization is given and design charts are introduced to facilitate optimizing the performance of the injector. Full-cone injector is a more suitable choice for monopropellant thruster and it might be available commercially.

The Design of Mechanical Grates Experimental Device of Municipal Solid Waste

In order to research the impact of the structure parameters of mechanical grate on MSW(Municipal Solid Waste) movement characteristics such as transportation speed, average stop time and mixed rate of waste, a kind of mechanical grate cold experimental device has been designed. This device can realize the switch between push forward and backward. Many structure parameters can be adjusted such as the height of grate, move distance of grate, bed angle, and move speed of the grate. Based on Mechanical grate cold experimental device, to study the impact of the mechanical grate structure parameters on the characteristics of waste movement is conducive to applying the results of test to the actual MSW grate incinerator. It provides a strong basis for the improvement and optimization of the mechanical grate furnace in terms of characteristics of Chinese MSW.

Assessment of the influencing factors on subsidence at abandoned coal mines in South Korea

This study deals with the characteristics of subsidence and the relationships between the subsidence factors over abandoned coal mines in South Korea. The subsidence factors that were investigated were the dip angle and thickness of the coal bed, mining depth, depth of subsidence, and subsidence area in 548 cases of subsidence that occurred throughout the country. A close relationship between the type of subsidence and mining method was identified. There was an intimate relation between the depth of subsidence and the dip angle of the coal bed, while the subsidence area proved to be in proportion to the thickness of the coal bed and mining depth and was in inverse proportion to the dip angle of the coal bed.

Observational Study of Head of Bed Elevation Adherence Using a Continuous Monitoring System in a Medical Intensive Care Unit

Head of bed elevation ≥ 30° reduces ventilator-associated pneumonia in mechanically ventilated patients, but adherence is variable and difficult to monitor continuously. Unlike many clinical variables, head of bed elevation is not electronically displayed or monitored with audible alarms. Continuous monitoring of head of bed elevation with audible alerts and visual cues when the elevation is < 30° will improve adherence by 15%. Head of bed elevation was continuously monitored and recorded on a central monitoring station and displayed on the bedside monitor of 16 of 24 medical intensive care unit beds. Manual bedside checks were performed twice daily at varying times. Continuous head of bed angle was available from 98 of 313 (31%) patient beds over a 7.5 month period, representing 322 of 1,373 mechanical ventilator days (24%). Continuous monitoring was performed for 7,720 hours, 5,542 hours with the data displayed on bedside monitors and 2,178 hours with the data available only from central monitors. Head of bed elevation was ≥ 30° for 76% of the hours when the data were displayed on bedside monitors, and for 61% of hours when it was not (P < <italic/>.001, odds ratio = 2.3, 95% CI 2.0-2.6). Intermittent bedside checks for head of bed elevation ≥ 30° found 97 ± 2% adherence. Real-time monitoring of head of bed elevation is feasible, and when combined with audible alarms and visual cues, improves ≥ 30° elevation adherence. Intermittent bedside checks over-estimate actual adherence.

J027053 ギャッチアップ角度が仰臥位姿勢における背圧軽減に及ぼす影響

J027053 ギャッチアップ角度が仰臥位姿勢における背圧軽減に及ぼす影響

Influence of Relative Density of Soil on Performance of Geocell-Reinforced Sand Foundations

The paper brings out the influence of relative density of foundation soil on performance improvement of geocell reinforcement; through model load tests on geocell-reinforced and unreinforced sand beds. Tests were carried out for five different relative densities of sand (30, 40, 50, 60, and 70%). The test results indicate that the beneficial effect of geocell reinforcement, in terms of increase in stiffness, bearing capacity, and load dispersion angle of the foundation bed, is present over a wide range of relative density; however, it is higher for dense condition of foundation soil. With geocell reinforcement offering three-dimensional confinement, the dilation induced benefit is substantially high for dense soil fill. Therefore, for effective utilization of geocell reinforcement, the foundation soil should be compacted to higher density.

Quantitative prediction of the oil-bearing height of Tertiary stratigraphic reservoirs in Jiyang Depression

Abstract The Tertiary stratigraphic reservoirs in Jiyang Depression are characterized by small buried-depth, long distance of trap from source, low oil-bearing height and poor oil physical property. Oil-bearing height is mainly determined by four factors: expulsion rate of source rock, migration distance, dip angle of carrier bed and capillary resistance force. Of these four factors, the expulsion rate can be expressed by the pressure factor gradient of source rock, the migration distance can be expressed by the horizontal and vertical distances between trap and source, and the capillary resistance force in carrier beds can be expressed by the capillary pressure in trap reservoirs. From the statistics of 62 stratigraphic reservoirs, oil-bearing height is in positive correlation with pressure factor gradient and dip angle of carrier bed and in negative correlation with horizontal and vertical distances between trap and source and capillary resistance force. On the basis of relations analysis between oil-bearing height and single factors, the multi-parameter match expression for the stratigraphic reservoir oil-bearing height has been established through multiple regressions. The application results show that the predicted value from match expression matches well with the true value. The expression can be used for the prediction of oil-bearing height of Tertiary stratigraphic reservoirs in Jiyang Depression.

股関節伸展可動域の大きさによる上位および下位腰椎の前彎増強の違い

Decrease in the hip extension range of motion (HE-ROM) can cause lumbar hyperlordosis. Hyperlordosis is one of the mechanisms underlying low back pain. A diagnosis of low back pain from hyperlordosis can be used to detect the area in which hyperlordosis occurs more easily—the upper or lower lumbar spine. Twenty-one men were recruited for this study. HE-ROM was measured manually. Lumbar alignment was measured on a bed in a prone position. We extended the subject's hip by bending the bed at 4 angles (0°, 10°, 15°, 30°) and measured the spinal alignment by using a SpinalMouse. The results showed that lumbar lordosis increased at the bed angles of 15°and 30°. Only when the bed angle was changed from 0° to 30°, the increased angle of the lumbar spine was negatively correlated to the HE-ROM (r=-0.46, p<0.05), particularly that of the lower lumbar spine (r=-0.47, p<0.05). These findings suggested that lower lumbar lordosis tends to increase in individuals with poor HE-ROM. Additionally, increase in lower lumbar lordosis is attributed to the tendency to have low back pain in the lower lumbar spine.

HEAD OF BED ANGLE EFFECTS TIDAL VOLUME IN MECHANICALLY VENTILATED PATIENTS IN THE INTENSIVE CARE UNIT

PURPOSE: Explore the effect of head of bed (HOB) angle on tidal volumes (Vt) delivered to patients on pressure support ventilation (PSV). Given the importance attached to compliance with the Institute of Healthcare Improvement's (IHI) ventilator care bundle mandating HOB at 30–45 degrees for the prevention of ventilator associated pneumonia (VAP), we decided to study the effect of HOB on Vt in patients being weaned using PSV.

Investigation on the ability of glowing firebrands deposited within crevices to ignite common building materials

A series of experiments was conducted to determine the range of conditions that glowing firebrands may ignite common building materials. The surface temperature of glowing firebrands burning under different applied airflow was quantified using an infrared camera. As the applied airflow was increased, the surface temperature of glowing firebrands was observed to increase. A crevice was constructed using plywood and oriented strand board (OSB) and the angle was varied to investigate the influence that this parameter has on promoting ignition after contact with glowing firebrands. The number of firebrands deposited within the constructed crevices was varied. Single firebrands were unable to ignite the materials used in this study over a range of applied airflows. For the tightest fuel bed angle of 60°, the glowing firebrands deposited on the fuel bed always resulted in smoldering ignition. For plywood, contact with glowing firebrands produced smoldering ignition followed by a transition to flaming ignition. At the fuel bed angle of 90°, no definitive ignition behavior was observed for either material; different ignition criteria (either no ignition or smoldering ignition) were observed under identical experimental conditions. As the fuel bed angle was increased up to 135°, ignition never occurred for both test fuel beds. For a given airflow and fuel bed material, the ignition delay time was observed to increase as the fuel bed angle was increased. A large difference was observed in the ignition delay time for plywood and OSB at a fuel bed angle of 90°. Based on these ignition results, the critical angle for ignition exists between 90° and 135° at a given airflow. These results clearly demonstrate that firebrands are capable of igniting common building materials.

The Effects of Different Types of Automated Inclining Bed and Tilt Angle on Body-Pressure Redistribution

The damage caused by pressure in bedridden hospitalized patients is attributable to the body tissues becoming compressed against bony prominences, which results in poor capillary perfusion. Automated inclining beds were developed in this study to assist patients in repositioning, with the aim of quantifying the effects of 3 types of bed (bed 1, 1-axis tilting; bed 2, 1-axis and 2-segment tilting; and bed 3, 2-axis and 3-segment tilting) and 3 tilt angles (10, 15, and 20 degrees upward from the horizontal) on body-pressure redistribution. Twenty healthy subjects (14 men and 6 women) aged 21 to 26 years were recruited from the Yonsei University student population (mean [SD]: height, 164.0 cm [5.5 cm]; weight, 58.7 kg [7.3 kg]). A body-pressure measurement system was used to analyze the pressure distributions of the human body for the different bed types and tilt angles. The results showed that pressure reduction was significantly greater for bed 2 than for beds 1 and 3, and for tilt angles of 15 and 20 degrees upward. The highest pressure reduction was found for bed 2, with a tilt angle of 20 degrees upward from the horizontal.

J1102-4-6 褥瘡好発部位の応力分布に対するギャッチアップ角度の影響(ライフサポート4:パワーアシスト・作業支援)

J1102-4-6 褥瘡好発部位の応力分布に対するギャッチアップ角度の影響(ライフサポート4:パワーアシスト・作業支援)

Unascertained measurement classifying model of goaf collapse prediction

Based on optimized forecast method of unascertained classifying, a unascertained measurement classifying model (UMC) to predict mining induced goaf collapse was established. The discriminated factors of the model are influential factors including overburden layer type, overburden layer thickness, the complex degree of geologic structure, the inclination angle of coal bed, volume rate of the cavity region, the vertical goaf depth from the surface and space superposition layer of the goaf region. Unascertained measurement (UM) function of each factor was calculated. The unascertained measurement to indicate the classification center and the grade of waiting forecast sample was determined by the UM distance between the synthesis index of waiting forecast samples and index of every classification. The training samples were tested by the established model, and the correct rate is 100%. Furthermore, the seven waiting forecast samples were predicted by the UMC model. The results show that the forecast results are fully consistent with the actual situation.

A simple device to increase rates of compliance in maintaining 30-degree head-of-bed elevation in ventilated patients

To determine whether a highly visible device that clearly indicates whether the head-of-bed is adequately elevated would increase rates of compliance with head-of-bed elevation guidelines. A prospective, single-center, multi-unit, two-phase study. Surgical, thoracic, trauma, and medical intensive care units. Cohort of intubated patients. A 4-wk trial was performed. At the onset of the trial, nurses were reminded to maintain head-of-bed elevation > 30 degrees. Over the subsequent 2 wks, head-of-bed elevations of intubated patient beds were measured. An Angle Indicator, designed to clearly display whether the head-of-bed was adequately elevated, was then placed on side rails of beds of ventilated patients, and head-of-bed elevation measurements were taken for an additional 2 wks. A survey was then handed out to nursing staff to assess satisfaction with the device. A total of 268 bed measurements were made. The average head-of-bed elevation was 21.8 degrees on beds without the device (n = 166) and 30.9 degrees on beds with the device (n = 102; p < .005). When compliance is defined as a bed angle of > or = 28 degrees, 23% of beds without the device were compliant while 71.5% of the beds with the device were compliant. The relative risk and odds ratio of having the device on a compliant bed were 2.2 and 9.25, respectively (p < .005). Seventy-two percent of nurses surveyed (n = 32) found it to be an improvement over existing methods, 88% found it helpful, and 84% would like it routinely used. The Angle Indicator improved rates of adherence to bed-elevation guidelines, and hospital staff found it helpful.

Ο κίνδυνος πλημμύρων από τον χείμαρρο Διακονιάρη του πολεοδομικού συγκροτήματος της πόλεως των Πατρών, ΒΔ Πελοπόννησος, Ελλάδα

Natural hazards, on a national and international scale, have increased in the last years as a consequence of climatic changes and human activity resulting in an unfavourable impact on socioeconomic conditions. Catastrophic phenomena related to river floods or slopes instability are natural hazards originating from seismic, tectonic and volcanic activity, as well as, from erosional and meteorological events, and human intervention. The Vulnerability being particularly high in the regions intensely populated, like the analyzed case study, high is the Risk. The importance of geomorphological studies in assessing natural hazards due to river floods was brought into focus with recent floods event that occurred in the Patras urban area (NW Péloponnèse) and particular from Diakoniaris river. Diakoniaris river is about 11 Km long, with mouth in Patraikos gulf. His bed angle slope ranges from 17°degrees of the high basin to 1°degrees of his alluvial playing. Due to geological and geomorphological characteristics of his basin, Diakoniaris is a temporary river. During summer season it is completely dry, whereas in autumn and winter time discharge increases remarkably. The area of Patras has a mean annual rainfall ranging from 698,5 to 747.3 mm. It flows in E-W direction, traversing the Patras town. During the autumn and winter months intense rainfalls persisted for several hours producing severe flash flood mainly in the alluvial playing of Diakoniaris River. There were some loss of life and damage to buildings, transport infrastructure and agricultural crops. Similar events happened also in southwestern Patras town in 1997, October and 2001, December. The damages are mainly due to absence of good alluvial playing management practices in recent decades, concretely after the year 1960 during the urban growth of the Patras town.