32 results on '"Tangential"'
Search Results
2. 3D Tibial Acceleration and Consideration of 3D Angular Motion Using IMUs on Peak Tibial Acceleration and Impulse in Running.
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VAN MIDDELAAR, ROBBERT P., ZHANG, JUNHAO, VELTINK, PETER H., and REENALDA, JASPER
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TIBIA physiology , *RUNNING , *PHYSIOLOGICAL effects of acceleration , *DESCRIPTIVE statistics , *RESEARCH funding , *BIOMECHANICS - Abstract
Purpose: Peak tibial acceleration (PTA) is defined as the peak acceleration occurring shortly after initial contact, often used as an indirect measure of tibial load. As the tibia is a rotating segment around the ankle, angular velocity and angular acceleration should be included in PTA. This study aimed to quantify three-dimensional tibial acceleration components over two different sensor locations and three running speeds, to get a better understanding of the influence of centripetal and tangential accelerations on PTA typically measured in running. Furthermore, it explores tibial impulse as an alternative surrogatemeasure for tibial load. Methods: Fifteen participants ran 90 s on a treadmill at 2.8, 3.3, and 3.9m·s--1,with inertialmeasurement units (IMUs) located distally and proximally on the tibia. Results: Without the inclusion of rotational accelerations and gravity, no significant difference was found between axial PTA between both IMU locations, whereas in the tangential sagittal plane axis, there was a significant difference. Inclusion of rotational accelerations and gravity resulted in similar PTA estimates at the ankle for both IMU locations and caused a significant difference between PTA based on the distal IMU and PTA at the ankle. The impulse showed more consistent results between the proximal and distal IMU locations compared with axial PTA. Conclusions: Rotational acceleration of the tibia during stance differently impacted PTA measured proximally and distally at the tibia, indicating that rotational acceleration and gravity should be included in PTA estimates. Furthermore, peak acceleration values (such as PTA) are not always reliable when using IMUs because of inconsistent PTA proximally compared with distally on an individual level. Instead, impulse seems to be a more consistent surrogate measure for the tibial load. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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3. EFFECTS OF CUTTING PARAMETERS AND GRAIN DIRECTION ON SURFACE QUALITY OF THREE WOOD SPECIES OBTAINED BY CNC MILLING.
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IBRISEVIC, Alen, OBUCINA, Murco, HAJDAREVIC, Seid, MIHULJA, Goran, KUZMAN, Manja Kitek, and BUSULADZIC, Ibrahim
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WOOD , *NUMERICAL control of machine tools , *CUTTING (Materials) , *GRAINING , *SURFACE roughness , *OAK , *BEECH , *FIR - Abstract
Computer Numerical Control (CNC) machines are increasingly popular in the production of furniture and wood products, because they combine high processing quality with short production time. The effective use of CNC machines depends on the processing parameters, which also affects the quality of the processed surface. The aim of this study was to determine the effect of feed rate, cutting direction, and grain direction on the surface roughness of various types of wood. Three European wood species (oak, beech, fir) were cut with a spindle speed of 16,000 rpm and two different feed rates (5,000 and 10,000 mm/min) using end mill tools on the CNC machine. The milling was performed in two cutting directions (radial and tangential) and two grain orientations (0° and 90°). An analysis of variance (ANOVA) was performed to evaluate the impact of the cutting parameters. The surface roughness measurements were taken, and two surface roughness parameters (Ra and Rz) were measured to determine the surface quality of the wood. According to the results of this study, the lowest surface roughness values, milling with the same processing parameters, occurred for oak wood, while the highest values occurred for fir. [ABSTRACT FROM AUTHOR]
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- 2023
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4. The tangential view described by Moneim to demonstrate scapholunate dissociation: an update.
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Imada, Allicia O., Welch, Kathryn, Mlady, Gary, and Moneim, Moheb S. A.
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JOINT instability , *CARPAL bones , *ARTICULAR ligaments , *WRIST injuries , *INTER-observer reliability , *WRIST - Abstract
Purpose: Scapholunate dissociation is a common and significant injury to the wrist. Radiographs are important in the diagnosis of this injury and in the planning of treatment. The tangential radiograph view was described almost 40 years ago as a method for accurately measuring scapholunate gaps. The hand is positioned on a 20° foam rubber block and the thumb on the cassette, which positions the scaphoid and lunate articular surfaces parallel, without patient discomfort or effort. The goal of this study was to review this method with more recent data and in a larger group of patients. Methods: Radiographs of 31 patients who had scapholunate interosseous ligament tears and surgical repair over a 9 year period were retrospectively evaluated. Each of the four authors independently measured scapholunate gaps for posteroanterior and tangential views. Results: The tangential view gaps were significantly greater than the posteroanterior gaps overall. Similar results were found for borderline cases where the posteroanterior gap was less than 3 mm. Every tangential view gap measurement was greater than its respective posteroanterior gap with good inter-rater reliability. Conclusion: The tangential view is a reliable radiographic method to identify scapholunate gaps. It should be obtained when there is clinical concern for scapholunate dissociation, especially in patients with borderline posteroanterior gaps. [ABSTRACT FROM AUTHOR]
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- 2023
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5. You Take the Low Road: Differential Outcomes After Tangential and Transcortical Approaches to Medial Temporal Brain Arteriovenous Malformations.
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Scherschinski, Lea, Srinivasan, Visish M., Karahalios, Katherine, Garcia, Joseph H., Koester, Stefan W., Jubran, Jubran H., Benner, Dimitri, Winkler, Ethan A., Catapano, Joshua S., Labib, Mohamed A., Graffeo, Christopher S., and Lawton, Michael T.
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CEREBRAL arteriovenous malformations , *MONTREAL Cognitive Assessment , *NEUROPHYSIOLOGIC monitoring , *POSTOPERATIVE period , *DEMOGRAPHIC characteristics , *DATABASES - Abstract
Microsurgical resection of medial temporal brain arteriovenous malformations (AVMs) is typically conducted through 2 approaches: the orbitozygomatic-tangential and subtemporal-transcortical. Relative indications and outcomes for these techniques have not been formally compared. The cerebrovascular database of a quaternary center was reviewed for patients with medial temporal AVMs treated between January 1, 1997, and July 31, 2021. Demographic characteristics, lesion characteristics, surgical approaches, and outcomes were retrospectively analyzed and compared. Postoperative outcome testing was performed using the Montreal Cognitive Assessment and Global Quality of Life Scale. Fifty-nine patients were assessed. Mean (standard deviation) age was 31 (18) years; 30 (51%) patients were male. Of the AVMs, 29 (49%) were left-sided and 30 (51%) were right-sided. The tangential approach was selected in 20 (34%) cases, whereas the transcortical technique was preferred in 39 (66%). Improved modified Rankin Scale status was significantly associated with the tangential resection technique both in the early postoperative period (P = 0.02) and at last follow-up (P = 0.01). Differences between the tangential and transcortical approaches were not significant with respect to new postoperative deficits (5/20 [25%] vs. 12/39 [31%], P = 0.87) or the presence of residual AVM on follow-up angiography (1/20 [6%] vs. 5/39 [14%], P = 0.65). The orbitozygomatic-tangential strategy was associated with favorable functional and quality-of-life outcomes after medial temporal AVM resection. These benefits are likely to be attributable to minimization of temporal retraction, avoidance of brain transgression, and avoidance of traction on the vein of Labbé, rendering the orbitozygomatic-tangential approach the preferred option for cases that are anatomically amenable to either strategy. [ABSTRACT FROM AUTHOR]
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- 2023
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6. A general approach to multivariable recursive interpolation.
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Gombani, A. and Michaletzky, Gy.
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INTERPOLATION , *LINEAR control systems , *PROPORTIONAL representation , *LINEAR algebra , *INTERPOLATION algorithms - Abstract
We consider here the problem of constructing a general recursive algorithm to interpolate a given set of data with a rational function. While many algorithms of this kind already exist, they are either providing non-minimal degree solutions (like the Schur algorithm) or exhibit jumps in the degree of the interpolants (or of the partial realization, as the problem is called when the interpolation is at infinity, see Rissanen (SIAM J Control 9(3):420–430, 1971) and Gragg and Lindquist (in: Linear systems and control (special issue), linear algebra and its applications, vol 50. pp 277–319, 1983)). By imbedding the solution into a larger set of interpolants, we show that the increase in the degree of this representation is proportional to the increase in the length of the data. We provide an algorithm to interpolate multivariable tangential sets of data with arbitrary nodes, generalizing in a fundamental manner the results of Kuijper (Syst Control Lett 31:225–233, 1997). We use this new approach to discuss a special scalar case in detail. When the interpolation data are obtained from the Taylor-series expansion of a given function, then the Euclidean-type algorithm plays an important role. [ABSTRACT FROM AUTHOR]
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- 2021
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7. Effects of Cross-sectional Geometry and Force Direction on Bending Strength and Modulus of Elasticity of Some Softwood Beams.
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Güray, Ersan, Kasal, Ali, Demirci, Selçuk, Ceylan, Erkan, and Kuşkun, Tolga
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The effects of cross-sectional geometry and force direction on bending strength (MOR) and modulus of elasticity (MOE) were investigated in selected softwoods. The specimens were constructed of Scots pine (Pinus sylvestris), Black pine (Pinus nigra), Siberian pine (Pinus sibirica), Stone pine (Pinus pinea), Nordmann fir (Abies nordmanniana), Oriental spruce (Picea orientalis), and Lebanon cedar (Cedrus libani). A total of 280 specimens were prepared from these seven species in two different cross-sectional geometries (circular and square, equal in area) and tested in two characteristic force directions (tangential and radial) by 10 replications. They were subjected to three-point bending tests according to TS 2474 (2005) and TS 2478 (2005) to obtain the MOR and MOE. The results showed that the type of cross-sectional area and direction of applied force, individually or together, had considerable effects on the MOR and MOE. The MOR values of the circular-sectioned specimens were 5% greater than those of the square-sectioned specimens. The MOE values of the circular-sectioned specimens were on average 19% greater than those of the square-sectioned specimens. The MOR and MOE values were on average 7% and 17% greater, respectively, for the force applied in the tangential direction. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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8. Radial and tangential error analysis of double-flank gear measurement.
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Tang, Jie, Zhang, Yu, and Shi, Zhaoyao
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GEARING machinery dynamics , *TANGENTIAL coordinates , *DEGREES of freedom , *RADIAL basis functions , *GEARING machinery ,DESIGN & construction - Abstract
To clarify or interpret the measurement results of double-flank gear measurement (DFGM), the mathematical model of radial and tangential error analysis of double-flank gear measurement is established. Using differential method, the mathematical model of surface-to-surface contact stage is concerned, and also the tip-to-surface interference stage is involved. The error sources including the base radius error (or profile slope deviation) and the tooth space angle error (or single pitch deviation) of the gear to be measured are concerned. A case study of the gear parameter with the gear contact ratio 1.77 is discussed to explain the tooth contact process, in which the critical contact points are listed for determining the rotation angle. The radial and tangential composite deviations are simulated under different sign combination or different value of the error sources to cover as many results as possible. The simulation results are compared with the measurement results on a gear measuring device (GMD) using double flank rack probe (DFRP), whereby the simulation parameters are determined through the gear profile slope deviation and the single pitch deviation of the gear measured on a Gear Measuring Center Klingelnberg P26. The curves of the simulation results and the measurement results on GMD are consistent to each other. For gear grade 6 according to ISO 1328-1:2013, the allowable value of the total profile deviation is 11.5 μm. The simulation results are compared with the measurement results on a gear measuring device (GMD) based on double flank rack probe (DFRP). The difference between the peak to peak value of the simulation results and the mean line of the measurement results within the evaluation range is 1 μm in radial direction and 1.3 μm in tangential direction, which means the simulation results has better consistency with the measurement results. The radial and tangential error analysis of DFGM can not only be used in simulation of the results, but also in interpreting the DFGM measurement results, which is helpful for gear measurement and quality control. [ABSTRACT FROM AUTHOR]
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- 2018
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9. Analytical and empirical models of tornado vortices: A comparative study.
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Kim, Yong Chul and Matsui, Masahiro
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TORNADOES , *AXIAL flow , *VELOCITY measurements , *TANGENTIAL coordinates , *VORTEX motion - Abstract
Tornadoes are generally defined as rotating columns of air characterized by small size, axisymmetry and short duration. Thus, the nature of tornadic wind load is basically different from that of synoptic wind. As direct measurements of velocities are very difficult and limited, lots of empirical and theoretical expressions of tornadic wind have been proposed. In the present study, characteristics of several numerical expressions were investigated, and it was found that the characteristics of velocity fields vary widely from model to model, making it difficult to choose one that is generally applicable. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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10. A novel mixed-mode cohesive formulation for crack growth analysis.
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Nguyen, Nhung and Waas, Anthony M.
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COHESIVE strength (Mechanics) , *FRACTURE mechanics , *TRACTION (Engineering) , *INTERFACES (Physical sciences) , *CRACK propagation (Fracture mechanics) , *FLEXURAL strength - Abstract
Modeling fracture with a cohesive zone model requires an appropriate cohesive law for correlating interfacial tractions and crack face separation, especially in mixed-mode loading scenarios. Various approaches have been employed in order to develop such a law which can be characterized into potential-based and non-potential-based formulations. A critical re-examination of these methods is presented here, followed by a novel mixed-mode formulation which satisfies a physical criterion for crack propagation. Specifically, as the crack propagates, the trailing current crack tip is defined through the vanishing of normal and tangential components of the interfacial tractions simultaneously. A general formulation for mixed-mode conditions is proposed in this paper. In particular, given normal and tangential traction separation laws for pure normal and tangential modes as being material properties, the normal and tangential traction separation laws in mixed-mode loading are formulated so that all traction components disappear at the same effective separation when the crack advances. The new mixed-mode law is used to analyze three standard fracture problems in laminated composites, including double cantilever beam (DCB), end-notch flexure (ENF), and mixed-mode bending (MMB). A comparison with predictions from some selected mixed-mode cohesive laws and experimental data available in the literature is also included to further validate the proposed mixed-mode law. [ABSTRACT FROM AUTHOR]
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- 2016
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11. Properties of stability, bifurcation, and chaos of the tangential motion disk brake.
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Wei, Daogao, Ruan, Jingyu, Zhu, Weiwei, and Kang, Zuheng
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STABILITY (Mechanics) , *BIFURCATION theory , *CHAOS theory , *TANGENTIAL acceleration (Physics) , *DISC brakes , *NOISE , *TORSIONAL vibration - Abstract
This study proposes a new dynamic model of a brake system that combines pad tangential motion and disk torsional motion to reduce the vibration and noise of the brake system. The stability analysis of this system with a smoothed Stribeck friction model verified its instability, which is caused by Hopf bifurcation. Moreover, numerical simulation showed several phenomena of the system vibration changing with angular velocity: (1) the system vibration maintains in the stable limit cycle after Hopf bifurcation within a relatively wide range of low angular velocity and (2) period-doubling bifurcation and chaos will occur only by decreasing the angular velocity. This study further discusses the effects of friction parameter on stick–slip vibration within a common range of brake pressure under “low” and “lower” angular velocities; the result shows that a decrease of both μ s − μ k and decay factor can effectively reduce the range of chaotic vibration region. [ABSTRACT FROM AUTHOR]
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- 2016
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12. Modeling the Cupping of Lumber.
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Mitchell, Philip H.
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MOISTURE in wood , *LUMBER , *PLANT species , *DEFORMATIONS (Mechanics) , *CARTESIAN coordinates , *MATHEMATICAL models - Abstract
Wood shrinks anisotropically as it loses hygroscopic moisture. While longitudinal shrinkage (parallel to the grain) is nearly negligible in normal wood, transverse shrinkage (across the grain) is significant and characterized as tangential and radial shrinkage. The application of average tangential shrinkage values to a rectangular cross section results in errors, especially for boards cut from near the center of the log. In addition, using a Cartesian coordinate system to calculate shrinkage cannot provide an estimate of cup. Calculating shrinkage and cup deformation using a previously developed model, this Excel model can provide a more realistic image of the final cross section and a more accurate estimate of shrinkage. The model is dependent on wood species, initial and final moisture contents, and location of the board within the log. This paper describes and illustrates uses of the model. [ABSTRACT FROM AUTHOR]
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- 2016
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13. Is emergent cervical radiological evaluation mandatory in isolated cranial gunshot injury?
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Yilmaz, Atilla and Cakir, Murteza
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MEDICAL radiology , *CERVICAL vertebrae injuries , *EMERGENCY medical services - Abstract
Aim: The aim of this study was to evaluate the accompanied cervical injuries of the patients presenting to the emergency department (ED) because of penetrating, perforating or tangential cranial gunshot injuries (CGI). Material and Methods: The retrospective study included 137 patients that presented to the EDs at Mustafa Kemal and Ataturk University due to penetrating, perforating or tangential CGI between 2014 and 2018. Patients younger than 12 years old and had insufficient radiological records were excluded from the study and thus 115 patients were included in the study. Results: 115 patients included 105 (91%) men and 10 (9%) women with a mean age of 27 (range, 12-65) years. Of the 115 injuries, 84 (73%) were high-velocity and 31 (27%) were low-velocity gunshot injuries. The injuries included 92 (80%) penetrating or perforating and 23 (20%) tangential injuries. No cervical dislocation injury was accompanied by CGI in any patient. Unilateral lamina fracture of the cervical vertebra was observed in one patient. Conclusion: Our results support the opinion that isolated penetrating, perforating or tangential CGI did not cause to cervical spinal injuries, the intubation or tracheostomy procedures should not be postponed after radiological evaluation of cervical spinal stability. [ABSTRACT FROM AUTHOR]
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- 2018
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14. The Doubling Theory Corrects the Titius-Bode Law and Defines the Fine Structure Constant in the Solar System.
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Garnier-Malet, Jean-Pierre
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DYNAMICS , *SOLAR system , *PLANETS , *KUIPER belt , *INFORMATION technology , *INTERSTELLAR medium - Abstract
The fundamental movement of the “doubling theory”, developed in our preceding papers, is applied as a model of the dynamics of the solar system. It is shown that this model justifies and corrects the distances of the planets given by the Titius-Bode law, and predicts new planets between the Kuiper Belt and the Oort Cloud. Indeed, the empirical Titius-Bode law defines in an approximate way the distances of the planets to the sun, and becomes totally false for the most distant planets (Neptune and Pluto) and does not include the Oort Cloud and Kuiper Belt. The doubling theory is based on successive embedded finite structures of space-time domain at different scale levels. The cycle of the doubling movement in the solar system corresponds to 25920 years. It is shown that this cycle defines the fine structure constant. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
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15. Electrokinetics in undeveloped flows.
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Yaroshchuk, Andriy, Bernal, Edxon Eduardo Licón, and Luxbacher, Thomas
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ELECTROKINETICS , *FLUID dynamics , *COMPUTER simulation , *ELECTRODYNAMICS , *TANGENTIAL force , *FORCE & energy - Abstract
Highlights: [•] In tangential electrokinetics, flow becomes undeveloped at channel heights>150μm. [•] Streaming-current coefficient is a sub-linear function of channel height. [•] Numerical simulation of undeveloped flows improves interpretation. [•] It is advisable to use channel heights below 100–150μm. [Copyright &y& Elsevier]
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- 2013
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16. Cellular and molecular mechanisms controlling the migration of neocortical interneurons.
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Marín, Oscar
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INTERNEURONS , *GABA , *CEREBRAL cortex , *NEURAL circuitry , *REGULATION of neural transmission , *CELLULAR control mechanisms - Abstract
The discovery, approximately 15 years ago, that cortical GABAergic interneurons originate outside the pallium has revolutionized our understanding of the development of the cerebral cortex. It is now clear that glutamatergic pyramidal cells and GABAergic interneurons follow largely distinct development programs, a notion that has challenged our views on how these neurons assemble to form precise neural circuits. In this review, I summarize our current knowledge of the mechanisms that control the migration of neocortical interneurons, a process that can be subdivided into three consecutive phases: migration to the cortex, intracortical dispersion, and layering. [ABSTRACT FROM AUTHOR]
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- 2013
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17. Automated Planning of Tangential Breast Intensity-Modulated Radiotherapy Using Heuristic Optimization
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Purdie, Thomas G., Dinniwell, Robert E., Letourneau, Daniel, Hill, Christine, and Sharpe, Michael B.
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MAMMOGRAMS , *HEURISTIC , *RADIOTHERAPY , *ROBUST control , *COST effectiveness , *SIMULATION methods & models - Abstract
Purpose: To present an automated technique for two-field tangential breast intensity-modulated radiotherapy (IMRT) treatment planning. Method and Materials: A total of 158 planned patients with Stage 0, I, and II breast cancer treated using whole-breast IMRT were retrospectively replanned using automated treatment planning tools. The tools developed are integrated into the existing clinical treatment planning system (Pinnacle3) and are designed to perform the manual volume delineation, beam placement, and IMRT treatment planning steps carried out by the treatment planning radiation therapist. The automated algorithm, using only the radio-opaque markers placed at CT simulation as inputs, optimizes the tangential beam parameters to geometrically minimize the amount of lung and heart treated while covering the whole-breast volume. The IMRT parameters are optimized according to the automatically delineated whole-breast volume. Results: The mean time to generate a complete treatment plan was 6 min, 50 s ± 1 min 12 s. For the automated plans, 157 of 158 plans (99%) were deemed clinically acceptable, and 138 of 158 plans (87%) were deemed clinically improved or equal to the corresponding clinical plan when reviewed in a randomized, double-blinded study by one experienced breast radiation oncologist. In addition, overall the automated plans were dosimetrically equivalent to the clinical plans when scored for target coverage and lung and heart doses. Conclusion: We have developed robust and efficient automated tools for fully inversed planned tangential breast IMRT planning that can be readily integrated into clinical practice. The tools produce clinically acceptable plans using only the common anatomic landmarks from the CT simulation process as an input. We anticipate the tools will improve patient access to high-quality IMRT treatment by simplifying the planning process and will reduce the effort and cost of incorporating more advanced planning into clinical practice. [Copyright &y& Elsevier]
- Published
- 2011
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18. Experimental investigation of a gas–solid rotating bed reactor with static geometry
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Ekatpure, Rahul P., Suryawanshi, Vaishali U., Heynderickx, Geraldine J., de Broqueville, Axel, and Marin, Guy B.
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GAS-solid interfaces , *CHEMICAL reactors , *HYDRODYNAMICS , *GAS flow , *PARTICLES , *CENTRIFUGAL force , *CHEMICAL processes - Abstract
Abstracts: Hydrodynamics of a gas–solid rotating bed reactor (RBR) in static geometry are investigated. Tangential injection of a gas at mass flow rate of 0.4–1kg/s in a cylindrical vessel with a diameter of 0.54m generates a rotating gas phase flow field. Introduction of solid particles in this field results into an annular dense gas–solid rotating bed. A stable annular gas–solid rotating bed without solids particles loss is achieved over a wide range of operating conditions. Goal of the presented work is to investigate, by means of experiments, the window for a stable operation of the gas–solid RBR, as a function of the solid particle diameter and density, the geometry of the RBR and the gas flow rate. If the solid particle diameter is comparable to tangential gas injection slot width, the establishment of a stable flow is delayed due to an increased slugging tendency. The upper limit of the solids content is found to decrease with decreasing solid particle diameter. Obtained experimental cold flow results are the initial steps in assessing the potentials of a RBR as an efficient gas–solid processing reactor from a process intensification point of view. [ABSTRACT FROM AUTHOR]
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- 2011
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19. Curved motions in horizontal and vertical orientations
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Phillips, J.G. and Ogeil, R.P.
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GRAPHOLOGY , *BLACKBOARDS , *GRAVITATIONAL fields , *PHYSIOLOGICAL effects of acceleration , *HUMAN mechanics , *CURVATURE , *HUMAN physiology ,WRITING - Abstract
Abstract: A consideration of handwriting demonstrates that motions can be remarkably constant, even when performed with different effectors. Nevertheless, the transposition of writing from horizontal to vertical orientations, as occurs when writing on blackboards, poses additional problems for the constraint of movement. Motions in horizontal and vertical planes potentially challenge the mechanisms responsible for motor constancy. Gravitational fields impose different accelerative forces on vertical (up/down) compared with horizontal (left/right) motions. A 1/3 power law linking tangential velocity and radius of curvature is sometimes invoked to explain how equivalent motions can be performed by different effectors. To evaluate the operation of the power law when movements are performed in different orientations, 12 participants drew ellipses in horizontal and vertical planes at about 1 or 2Hz. Mean tangential velocity, radius of curvature and the strength of the 1/3 power law were analyzed. The power law was strongest for curved motions at faster speeds. The power law was weakest at slower speeds in the vertical orientation. As participants controlled their movement periodicity, this placed tighter constraints upon curvature in the vertical orientations than the horizontal orientations. Speed of motion had a greater effect upon curvatures in the horizontal than the vertical orientation. The data offer insights into variations in the strength of the power law under different orientations, and indicate a limited role for the 1/3 power law in motor constancy. [Copyright &y& Elsevier]
- Published
- 2010
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20. A PRELIMINARY STUDY ON ULTRASONIC TREATMENT EFFECT ON TRANSVERSE WOOD PERMEABILITY.
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Tanaka, Takashi, Avramidis, Stavros, and Shida, Satoshi
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THERAPEUTIC use of ultrasonic imaging , *RADIAL nerve , *TANGENTIAL coordinates , *AIR flow , *GAS flow - Abstract
Ultrasonic pre-treatment of small and pressure saturated Douglas-fir heartwood specimens at 20 kHz fixed frequency with an acoustic horn resulted in increased specific permeability coefficient in both radial and tangential directions. Statistical analysis revealed that there was a high correlation between ultrasonic treatment time and specific permeability coefficient. Improvement rate of permeability in both radial and tangential directions was nearly the same regardless of treatment time. [ABSTRACT FROM AUTHOR]
- Published
- 2010
21. POLYNOMIAL EXTENSION OPERATORS. PART II.
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DEMKOWICZ, LESZEK, GOPALAKRISHNAN, JAYADEEP, and SCHÖBERL, JOACHIM
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FINITE element method , *POLYNOMIALS , *VECTOR analysis , *NUMERICAL analysis , *CAD/CAM systems - Abstract
Consider the tangential trace of a vector polynomial on the surface of a tetrahedron. We construct an extension operator that extends such a trace function into a polynomial on the tetrahedron. This operator can be continuously extended to the trace space of H(curl). Furthermore, it satisfies a commutativity property with an extension operator we constructed in Part I of this series. Such extensions are a fundamental ingredient of high order finite element analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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22. Genetic mapping of Foxb1-cell lineage shows migration from caudal diencephalon to telencephalon and lateral hypothalamus.
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Zhao, Tianyu, Szabó, Nora, Ma, Jun, Luo, Lingfei, Zhou, Xunlei, and Alvarez‐Bolado, Gonzalo
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GENE mapping , *CELL lines , *HYPOTHALAMUS , *AMYGDALOID body , *CELL migration - Abstract
The hypothalamus is a brain region with vital functions, and alterations in its development can cause human disease. However, we still do not have a complete description of how this complex structure is put together during embryonic and early postnatal stages. Radially oriented, outside-in migration of cells is prevalent in the developing hypothalamus. In spite of this, cell contingents from outside the hypothalamus as well as tangential hypothalamic migrations also have an important role. Here we study migrations in the hypothalamic primordium by genetically labeling the Foxb1 diencephalic lineage. Foxb1 is a transcription factor gene expressed in the neuroepithelium of the developing neural tube with a rostral expression boundary between caudal and rostral diencephalon, and therefore appropriate for marking migrations from caudal levels into the hypothalamus. We have found a large, longitudinally oriented migration stream apparently originating in the thalamic region and following an axonal bundle to end in the anterior portion of the lateral hypothalamic area. Additionally, we have mapped a specific expansion of the neuroepithelium into the rostral diencephalon. The expanded neuroepithelium generates abundant neurons for the medial hypothalamus at the tuberal level. Finally, we have uncovered novel diencephalon-to-telencephalon migrations into septum, piriform cortex and amygdala. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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23. POLYNOMIAL EXTENSION OPERATORS. PART I.
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Demkowicz, Leszek, Gopalakrishnan, Jayadeep, and Schöberl, Joachim
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ALGEBRAIC functions , *SOBOLEV spaces , *POLYNOMIALS , *FINITE element method , *PHILOSOPHY of mathematics - Abstract
In this series of papers, we construct operators that extend certain given functions on the boundary of a tetrahedron into the interior of the tetrahedron, with continuity properties in appropriate Sobolev norms. These extensions are novel in that they have certain polynomial preservation properties important in the analysis of high order finite elements. This part of the series is devoted to introducing our new technique for constructing the extensions, and its application to the case of polynomial extensions from H½(∂K) into H¹(K), for any tetrahedron K. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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24. A novel integrated MEG and EEG analysis method for dipolar sources
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Huang, Ming-Xiong, Song, Tao, Hagler, Donald J., Podgorny, Igor, Jousmaki, Veikko, Cui, Li, Gaa, Kathleen, Harrington, Deborah L., Dale, Anders M., Lee, Roland R., Elman, Jeff, and Halgren, Eric
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ELECTROENCEPHALOGRAPHY , *DIAGNOSIS of brain diseases , *MEDICAL imaging systems , *NEUROSCIENCES - Abstract
Abstract: The ability of magnetoencephalography (MEG) to accurately localize neuronal currents and obtain tangential components of the source is largely due to MEG''s insensitivity to the conductivity profile of the head tissues. However, MEG cannot reliably detect the radial component of the neuronal current. In contrast, the localization accuracy of electroencephalography (EEG) is not as good as MEG, but EEG can detect both the tangential and radial components of the source. In the present study, we investigated the conductivity dependence in a new approach that combines MEG and EEG to accurately obtain, not only the location and tangential components, but also the radial component of the source. In this approach, the source location and tangential components are obtained from MEG alone, and optimal conductivity values of the EEG model are estimated by best-fitting EEG signal, while precisely matching the tangential components of the source in EEG and MEG. Then, the radial components are obtained from EEG using the previously estimated optimal conductivity values. Computer simulations testing this integrated approach demonstrated two main findings. First, there are well-organized optimal combinations of the conductivity values that provide an accurate fit to the combined MEG and EEG data. Second, the radial component, in addition to the location and tangential components, can be obtained with high accuracy without needing to know the precise conductivity profile of the head. We then demonstrated that this new approach performed reliably in an analysis of the 20-ms component from human somatosensory responses elicited by electric median-nerve stimulation. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
25. Abnormal laminar position and dendrite development of interneurons in the reeler forebrain
- Author
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Yabut, Odessa, Renfro, Amy, Niu, Sanyong, Swann, John W., Marín, Oscar, and D'Arcangelo, Gabriella
- Subjects
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DENDRITES , *INTERNEURONS , *GREEN fluorescent protein , *PROSENCEPHALON - Abstract
Abstract: The majority of cortical and hippocampal interneurons originate in the subcortical telencephalon and migrate tangentially into pallial regions before settling in various cortical layers. The molecular cues that regulate final positioning of specific interneurons in cortical structures have not yet been identified. The positioning of radially migrating principal neurons of the cortex and hippocampus depends upon Reelin, an extracellular protein expressed near the pial surface during embryonic development that is absent in reeler mutant mice. To determine whether the layer specification of interneurons, like that of principal neurons, requires Reelin, we crossed reeler with transgenic mice that contain Green Fluorescent Protein (GFP)-expressing Inhibitory Neurons (GINs). These neurons express basal forebrain markers Dlx1/2 in normal and reeler mice. In normal mice, GINs express Reelin and are localized to specific layers of the cortex and hippocampus. In reeler mutant mice, we show that GINs migrate normally into the pallium, but fail to acquire proper layer position. Double labeling experiments indicate that the neurochemical profile of these interneurons is not generally altered in reeler mice. However, the extension of their cellular processes is abnormal. Quantitative analysis of GINs in the cortex revealed that they are hypertrophic, bearing longer neuritic branches than normal. Thus, the lack of Reelin signaling results in abnormal positioning and altered morphology of forebrain interneurons. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
26. Molecular Interaction between Projection Neuron Precursors and Invading Interneurons via Stromal-Derived Factor 1 (CXCL12)/CXCR4 Signaling in the Cortical Subventricular Zone/Intermediate Zone.
- Author
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Tiveron, Marie-Catherine, Rossel, Mireille, Moepps, Barbara, Yong Li Zhang, Seidenfaden, Ralph, Favor, Jack, König, Norbert, and Cremer, Harold
- Subjects
- *
INTERNEURONS , *NEOCORTEX , *CEREBRAL cortex , *NERVOUS system , *SPATIAL ability , *TEMPORAL integration , *CHEMOKINES - Abstract
Most cortical interneurons are generated in the subpallial ganglionic eminences and migrate tangentially to their final destinations in the neocortex. Within the cortex, interneurons follow mainly stereotype routes in the subventricular zone/intermediate zone (SVZ/IZ) and in the marginal zone. It has been suggested that interactions between invading interneurons and locally generated projection neurons are implicated in the temporal and spatial regulation of the invasion process. However, so far experimental evidence for such interactions is lacking. We show here that the chemokine stromal-derived factor 1 (SDF-1; CXCL12) is expressed in the main invasion route for cortical interneurons in the SVZ/IZ. Most SDF-1-positive cells are proliferating and express the homeodomain transcription factors Cux1 and Cux2. Using MASH-1 mutant mice in concert with the interneuron marker DLX, we exclude that interneurons themselves produce the chemokine in an autocrine manner. We conclude that the SDF-1-expressing cell population represents the precursors of projection neurons during their transition and amplification in the SVZ/IZ. Using mice lacking the SDF-1 receptor CXCR4 or Pax6, we demonstrate that SDF-1 expression in the cortical SVZ/IZ is essential for recognition of this pathway by interneurons. These results represent the first evidence for a molecular interaction between precursors of projection neurons and invading interneurons during corticogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
27. TEILHARD'S TWO ENERGIES.
- Author
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Morowitz, Harold J., Schmitz-Moormann, Nicole, and Salmon, James F.
- Subjects
- *
BIOLOGICAL evolution , *RELIGION & science , *THERMODYNAMICS , *INFORMATION theory , *GIBBS' free energy - Abstract
Resolution of the entropy-evolution problem was a significant issue for Pierre Teilhard de Chardin throughout his scientific career. Although never truly satisfied with his solution, he proposed that all energy must be psychic and contain two components. Tangential energy is related to physical energy. Radial energy in some way accounts for increasing complexity and consciousness in evolution. Analysis of developments in thermodynamics, statistical mechanics, and information theory show that Gibbs free energy contains both calorimetric and noetic components, thus validating Teilhard's intuition. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
28. Injuries to the colon from blast effect of penetrating extra-peritoneal thoraco-abdominal trauma
- Author
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Sharma, Om P., Oswanski, Michael F., and White, Patrick W.
- Subjects
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COLON injuries , *GUNSHOT wounds , *DIAPHRAGM (Anatomy) , *LARGE intestine , *SPLEEN , *ABDOMINAL injuries , *CHEST injuries , *BLAST injuries , *DISEASE complications , *DIAGNOSIS - Abstract
Although rare, blast injury to the intestine can result from penetrating thoraco-abdominal extra-peritoneal gunshot (and shotgun) wounds despite the absence of injury to the diaphragm or to the peritoneum. Injuries of the spleen, small intestine and the mesentery by this mechanism have been previously reported in the world literature. This paper reports the first two cases of non-penetrating ballistic trauma to the colon. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
29. The Zebrafish trilobite Gene Is Essential for Tangential Migration of Branchiomotor Neurons
- Author
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Bingham, Stephanie, Higashijima, Shin-ichi, Okamoto, Hitoshi, and Chandrasekhar, Anand
- Subjects
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ZEBRA danio , *NEURONS , *GENES , *NERVOUS system - Abstract
Newborn neurons migrate extensively in the radial and tangential directions to organize the developing vertebrate nervous system. We show here that mutations in zebrafish trilobite (tri) that affect gastrulation-associated cell movements also eliminate tangential migration of motor neurons in the hindbrain. In the wild-type hindbrain, facial (nVII) and glossopharyngeal (nIX) motor neurons are induced in rhombomeres 4 and 6, respectively, and migrate tangentially into r6 and r7 (nVII) and r7 (nIX). In all three tri alleles examined, although normal numbers of motor neurons are induced, nVII motor neurons are found exclusively in r4, and nIX-like motor neurons are found exclusively in r6. The migration of other neuronal and nonneuronal cell types is unaffected in tri mutants. Rhombomere formation and the development of other hindbrain neurons are also unaffected in tri mutants. Furthermore, tangential neuronal migration occurs normally in the gastrulation mutant knypek, indicating that the trilobite neuron phenotype does not arise nonspecifically from aberrant gastrulation-associated movements. We conclude that trilobite function is specifically required for two types of cell migration that occur at different stages of zebrafish development. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
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30. The use of a compensator library to reduce dose inhomogeneity in tangential radiotherapy of the breast
- Author
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Wilks, Robin J. and Bliss, Peter
- Subjects
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RADIOTHERAPY , *BREAST - Abstract
Background and purpose: The dose variation throughout the volume of the breast from tangential fields can exceed 20% for large breasts. This is postulated to result in poor cosmesis [Radiother Oncol 16 (1989) 253], particularly at the inframammary fold, where the dose is highest. Compensators may be used to reduce this variation, but at the cost of the time to manufacture each unique compensator for the individual patients. This paper outlines the implementation and routine use of a library of reusable compensators.Materials and methods: For the period of December 1999 to May 2001, 94 patients attending for breast radiotherapy received treatment using breast compensators calculated from multiple outlines measured using the Osiris system. The compensators manufactured for the early patients were added to a library for possible reuse by later patients. Of the 94 patients, 28 patients’ compensators formed the library and 66 subsequent patients have been treated using compensators derived from the library. Selection of the most appropriate library compensator was determined from the analysis of the distribution of the calculated dose-volume histogram for the whole breast, excluding lung, penumbra and build-up regions. Once the library was complete, approximately 50% of all subsequent breast patients were treated with compensators (46% from the library and 4% with individual compensators). This represented a usage rate of 92% for the library compensators for those patients requiring compensation.Results: In all cases the compensators reduced the variation in the dose distribution. For example, the group treated with a library compensator demonstrated a mean reduction from 29 to 9% for the volume of breast tissue receiving more than 5% greater than the reference dose. If the same patients had been treated using their own individual compensators, the corresponding value would have been 7%. There is a small systematic, but negligible, difference in the two populations of dose variation for individual versus library compensators, but this difference (
P=0.20 ) did not reach the level of statistical significance ofP=0.05 ).Conclusion: The method of creation and selection of library compensators has proved to be simple and reliable in practice. Every patient receiving radiotherapy for breast cancer is currently investigated under full software control to ascertain whether the use of a library compensator would be advantageous. [Copyright &y& Elsevier]- Published
- 2002
- Full Text
- View/download PDF
31. Developing a three-dimensional tangential swirl plate photobioreactor to enhance mass transfer and flashlight effect for microalgal CO2 fixation.
- Author
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Song, Yanmei, Cheng, Jun, Lai, Xin, Guo, Wangbiao, and Yang, Weijuan
- Subjects
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FLASHLIGHTS , *CARBON dioxide , *SWIRLING flow , *MASS transfer , *NOZZLES , *TURBULENCE - Abstract
• The nozzle axes were tangential to a horizontal cylinder to form staggered vortexes. • The flow perpendicular to central-plane between two sidewalls was strengthened. • The best performance was achieved when θ = 22.1° and d/D = 0.34. • Flashlight frequency and CO 2 fixation rate increased by 90.9% and by 30%. A novel three-dimensional tangential swirl plate (TTSP) photobioreactor was proposed to strengthen flow perpendicular to central cross-section between two side walls, resulting in more widespread turbulence for improving microalgal CO 2 fixation. The axes of four center-symmetrically arranged nozzles were tangential to a horizontal cylinder to form two staggered vortexes. When angle θ between nozzle axis and central cross-section increased from 0° to 22.1° and then to 40.0°, mixing time and average bubble diameter first decreased to the minimum (16.55 s and 0.57 mm) and then increased. When relative diameter of tangential cylinder d/D increased from 0.11 to 0.34 and then to 0.56, flashlight frequency and light time ratio first increased to the maximum (0.21 Hz and 42.8%) and then decreased. Accordingly, flashlight frequency was 90.9% higher in TTSP photobioreactor than that in two-dimensional jet-aerated tangential swirl plate (JTSP) photobioreactor, leading to an increase in microalgal CO 2 fixation rate by 30%. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. Dose received by the sentinel node volume during tangential radiation therapy to the breast
- Author
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Zunino, Silvia B., Garrigo, Edgardo R., Garello, Nestor C., Murina, Patricia E., and Del Castillo, Rene
- Subjects
- *
HOSPITAL radiological services , *MEDICAL radiology , *MEDICAL electronics , *PATIENTS - Abstract
Abstract: The dose received by the sentinel node (SN) volume during tangential irradiation was studied on 31 patients. Of the 50Gy prescribed to the breast volume 95% of the SN volume received from 6.9 to 27.5Gy. In 19 patients the SN volume overlapped with the tangential field deep side. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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