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https://www.readbyqxmd.com/read/27929490/rounded-leaf-end-modeling-in-pinnacle-vmat-treatment-planning-for-fixed-jaw-linacs
#1
Lori A Young, Fei Yang, Ning Cao, Juergen Meyer
During volume-modulated arc therapies (VMAT), dosimetric errors are introduced by multiple open dynamic leaf gaps that are present in fixed diaphragm linear accelerators. The purpose of this work was to develop a methodology for adjusting the rounded leaf end modeling parameters to improve out-of-field dose agreement in SmartArc VMAT treatment plans delivered by fixed jaw linacs where leaf gap dose is not negligible. Leaf gap doses were measured for an Elekta beam modulator linac with 0.4 cm micro-multileaf collimators (MLC) using an A16 micro-ionization chamber, a MatriXX ion chamber detector array, and Kodak EDR2 film dosimetry in a solid water phantom...
November 8, 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27925591/kinesthetic-feedback-during-2dof-wrist-movements-via-a-novel-mr-compatible-robot
#2
Andrew Erwin, Marcia O'Malley, David Ress, Fabrizio Sergi
We demonstrate the interaction control capabilities of the MR-SoftWrist, a novel MR-compatible robot capable of applying accurate kinesthetic feedback to wrist pointing movements executed during fMRI. The MR-SoftWrist, based on a novel design that combines parallel piezoelectric actuation with compliant force feedback, is capable of delivering 1.5 N·m of torque to the wrist of an interacting subject about the flexion/extension and radial/ulnar axes. The robot workspace, defined by admissible wrist rotation angles, fully includes a circle with a 20 deg radius...
December 1, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/27916917/a-routing-protocol-for-multisink-wireless-sensor-networks-in-underground-coalmine-tunnels
#3
Xu Xia, Zhigang Chen, Hui Liu, Huihui Wang, Feng Zeng
Traditional underground coalmine monitoring systems are mainly based on the use of wired transmission. However, when cables are damaged during an accident, it is difficult to obtain relevant data on environmental parameters and the emergency situation underground. To address this problem, the use of wireless sensor networks (WSNs) has been proposed. However, the shape of coalmine tunnels is not conducive to the deployment of WSNs as they are long and narrow. Therefore, issues with the network arise, such as extremely large energy consumption, very weak connectivity, long time delays, and a short lifetime...
November 30, 2016: Sensors
https://www.readbyqxmd.com/read/27908172/design-of-a-dual-resolution-collimator-for-preclinical-cardiac-spect-with-a-stationary-triple-detector-system
#4
Stephen C Moore, Mi-Ae Park, Zhe Liu, Morgan C Lyon, Lindsay C Johnson, Victor H Lushear, James G Westberg, Scott D Metzler
PURPOSE: One approach to preclinical single-photon emission computed tomography (SPECT) imaging that provides both high resolution and high sensitivity is based on imaging a mouse inside a collimating tube; many magnified pinhole projection images from a small target region, e.g., the heart, can be recorded simultaneously on multiple detectors with little multiplexing since each pinhole aperture's opening angle is restricted to view mostly the target organ. However, to obtain complete data for reconstruction, it may be necessary to scan the mouse through the target region of the tube...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27902691/do-vascular-networks-branch-optimally-or-randomly-across-spatial-scales
#5
Elif Tekin, David Hunt, Mitchell G Newberry, Van M Savage
Modern models that derive allometric relationships between metabolic rate and body mass are based on the architectural design of the cardiovascular system and presume sibling vessels are symmetric in terms of radius, length, flow rate, and pressure. Here, we study the cardiovascular structure of the human head and torso and of a mouse lung based on three-dimensional images processed via our software Angicart. In contrast to modern allometric theories, we find systematic patterns of asymmetry in vascular branching, potentially explaining previously documented mismatches between predictions (power-law or concave curvature) and observed empirical data (convex curvature) for the allometric scaling of metabolic rate...
November 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27890215/-incidence-of-distal-ulna-fractures-associated-with-distal-radius-fractures-treatment-options
#6
G Herzberg, T Castel
Fractures of the neck and/or head of the ulna or distal ulna fracture (DUF) other than ulnar styloid fractures can occur in combination with distal radius fractures (DRF). This combination can have a significant influence on the treatment and prognosis since it causes the entire distal forearm to be unstable. In a series of 1279 consecutive unilateral DRFs, we found an associated ulnar neck fracture in 5.9% of cases, ulnar head and neck fracture in 1.6%, and isolated ulnar head fracture in 1.4%. Overall, 9% of cases in this study had a DUF with a DRF...
December 2016: Hand Surgery and Rehabilitation
https://www.readbyqxmd.com/read/27858087/three-dimensional-analysis-of-the-proximal-humeral-and-glenoid-geometry-using-microscribe-3d-digitizer
#7
Wejdan H Owaydhah, Mohammad A Alobaidy, Abdulrahman S Alraddadi, Roger W Soames
PURPOSE: To understand the geometry of the proximal humerus and glenoid fossa to facilitate the design of components used in shoulder arthroplasty. The aim is to evaluate the geometry of the proximal humerus and glenoid fossa and their relationship using a MicroScribe 3D digitizer. METHODS: Scans and measurements were obtained from 20 pairs of dry proximal humeri and scapulae [10 female and 10 male cadavers: median age 81 years (range 70-94 years)] using a MicroScribe 3D digitizer and Rhinoceros software...
November 17, 2016: Surgical and Radiologic Anatomy: SRA
https://www.readbyqxmd.com/read/27842972/influence-of-the-punch-head-design-on-the-physical-quality-of-tablets-produced-in-a-rotary-press
#8
Parthiban Anbalagan, Srimanta Sarkar, Celine V Liew, Paul W S Heng
This study aims to investigate the influence of tablet punch head design on compaction and the resultant tablet mechanical properties. Tablets were prepared using flat-face punches with different head flat and head radius configurations, on a rotary tablet press with compression rolls of different diameters. The results showed that tablets produced using punches with head flats consistently displayed higher tensile strengths and lower capping tendencies. Exclusion of the head flat in the punch head geometry caused the compacts to undergo a state of continual deformation during the compaction cycle, possibly with increasing elasticity without the opportunity for more prolonged stress relaxation...
November 11, 2016: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/27842781/patient-specific-hip-geometry-has-greater-effect-on-tha-wear-than-femoral-head-size
#9
Matej Daniel, Boris Rijavec, Drago Dolinar, David Pokorný, Aleš Iglič, Veronika Kralj-Iglič
In vivo linear penetration in total hip arthroplasty (THA) exhibits similar values for 28mm and 32mm femoral head diameter with considerable variations between and within the studies. It indicates factors other than femoral head diameter influence polyethylene wear. This study is intended to test the effect of patient׳s individual geometry of musculoskeletal system, acetabular cup orientation, and radius of femoral head on wear. Variation in patient׳s musculoskeletal geometry and acetabular cup placement is evaluated in two groups of patients implanted with 28mm and 32mm THA heads...
October 29, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27826904/forearm-lengthening-management-of-elbow-and-wrist
#10
REVIEW
Franck Launay, Sébastien Pesenti
The risk and consequences of an elbow or a wrist contracture are lower during a forearm lengthening than during a lower limb lengthening. This kind of complication can mostly be avoided by an active and intensive regimen of physiotherapy. However, there are some challenges to deal with in treating the disorder multiple exostoses and the radial club hand, including the lack of consensus on the best treatment for multiple exostoses. However, it is important to realize that the evolution of multiple exostoses can lead to a radial head dislocation which will damage the pronation and the supination range of motion...
December 2016: Journal of Children's Orthopaedics
https://www.readbyqxmd.com/read/27822697/annular-ligament-reconstruction-with-the-superficial-head-of-the-brachialis-surgical-technique-and-biomechanical-evaluation
#11
Michael Hackl, Kilian Wegmann, Christian Ries, Sebastian Lappen, Martin Scaal, Lars Peter Müller
PURPOSE: The purpose of this study was to perform biomechanical testing of annular ligament (AL) reconstruction using the superficial head of the brachialis tendon (SHBT) as a distally based tendon graft. We hypothesized that posterior translation of the radial head following AL reconstruction with an SHBT graft does not significantly differ from intact specimens. METHODS: Six fresh-frozen elbow specimens were used. The stability of the radial head against posterior translation forces (30 N) was evaluated in 0°, 45°, 90° and 120° of elbow flexion...
November 7, 2016: Surgical and Radiologic Anatomy: SRA
https://www.readbyqxmd.com/read/27815953/early-complications-associated-with-the-thompson-approach-to-the-proximal-radius
#12
Donato J Perretta, Kenneth M Brock, Nirmal C Tejwani
PURPOSE: The purpose of this study was to investigate the early complications associated with the dorsal approach to the proximal radius. This approach, also called the Thompson approach, is used relatively infrequently for the treatment of forearm fractures. It is primarily reserved for proximal one-third radius fractures where a volar plate may not be placed sufficiently proximal for adequate fixation. METHODS: A retrospective chart review was performed on forearm fractures performed at our institution...
November 2016: Bulletin of the Hospital for Joint Diseases
https://www.readbyqxmd.com/read/27788281/locomotor-hand-postures-carpal-kinematics-during-wrist-extension-and-associated-morphology-in-anthropoid-primates
#13
Caley M Orr
The biomechanics of wrist extension (or dorsiflexion) are important for understanding functional adaptation of the primate hand because extension mobility varies with habitual locomotor hand posture and facilitates certain manipulative tasks. Here, intercarpal kinematics are employed to investigate mechanisms underlying wrist extension in a sample of anthropoids representing various arboreal and terrestrial locomotor modes. Carpal kinematics are studied using computed-tomography of cadaveric forelimbs, and these data are combined with a morphometric analysis of biomechanically-informative anatomical features...
October 27, 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
https://www.readbyqxmd.com/read/27787923/age-and-sex-dependent-changes-of-intra-articular-cortical-and-trabecular-bone-structure-and-the-effects-of-rheumatoid-arthritis
#14
David Simon, Arnd Kleyer, Fabian Stemmler, Christoph Simon, Andreas Berlin, Axel J Hueber, Judith Haschka, Nina Renner, Camille Figueiredo, Winfried Neuhuber, Thomas Buder, Matthias Englbrecht, Juergen Rech, Klaus Engelke, Georg Schett
The objective of this cross-sectional study was to define normal sex- and age-dependent values of intra-articular bone mass and microstructures in the metacarpal heads of healthy individuals by high-resolution peripheral quantitative computed tomography (HR-pQCT) and test the effect of rheumatoid arthritis (RA) on these parameters. Human cadaveric metacarpal heads were used to exactly define intra-articular bone. Healthy individuals of different sex and age categories and RA patients with similar age and sex distribution received HR-pQCT scans of the second metacarpal head and the radius...
October 27, 2016: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
https://www.readbyqxmd.com/read/27781442/synchronization-of-multi-agent-systems-with-metric-topological-interactions
#15
Lin Wang, Guanrong Chen
A hybrid multi-agent systems model integrating the advantages of both metric interaction and topological interaction rules, called the metric-topological model, is developed. This model describes planar motions of mobile agents, where each agent can interact with all the agents within a circle of a constant radius, and can furthermore interact with some distant agents to reach a pre-assigned number of neighbors, if needed. Some sufficient conditions imposed only on system parameters and agent initial states are presented, which ensure achieving synchronization of the whole group of agents...
September 2016: Chaos
https://www.readbyqxmd.com/read/27780160/semicircular-canal-size-and-locomotion-in-colobine-monkeys-a-cautionary-tale
#16
Todd C Rae, Paul Martin Johnson, Wataru Yano, Eishi Hirasaki
The semicircular canals of the inner ear constitute the organ of balance, tracking head rotation during movement and facilitating stabilisation of vision. Morphological characteristics of the canals are correlated with agility scores related to locomotion. To date, however, the relationship between canal morphology and specific locomotor behaviours, such as leaping, is unclear. Knowledge of such a relationship could strengthen the inferences of locomotion of extinct taxa. To test this, crania of two sets of closely related primate species (Presbytis melalophos and P...
2016: Folia Primatologica; International Journal of Primatology
https://www.readbyqxmd.com/read/27730042/sapho-syndrome-with-acne-fulminans-and-severe-polyosteitis-involving-axial-skeleton
#17
B Lakshmi Divya, P Narasimha Rao
SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis), a rare inflammatory disorder, is an association of distinct skin disorders with pustules with osteoarticular inflammation. Its etiology remains unclear, and various treatment regimens frequently fail to control the disease. An 18-year-old male patient presented to the outpatient department with severe nodulocystic acne on the face with pain at both the wrists and lower back associated with high-grade fever and chills. On physical examination, he had severe tenderness at both wrist joints and lower back, along with swelling of right wrist...
September 2016: Indian Dermatology Online Journal
https://www.readbyqxmd.com/read/27729753/influence-of-myopia-on-size-of-optic-nerve-head-and-retinal-nerve-fiber-layer-thickness-measured-by-spectral-domain-optical-coherence-tomography
#18
Seok Hyun Bae, Shin Hee Kang, Chi Shian Feng, Joohyun Park, Jae Hoon Jeong, Kayoung Yi
PURPOSE: To investigate optic nerve head size and retinal nerve fiber layer (RNFL) thickness according to refractive status and axial length. METHODS: In a cross-sectional study, 252 eyes of 252 healthy volunteers underwent ocular biometry measurement as well as optic nerve head and RNFL imaging by spectral-domain optical coherence tomography. Correlation and linear regression analyses were performed for all subjects. The magnification effect was adjusted by the modified axial length method...
October 2016: Korean Journal of Ophthalmology: KJO
https://www.readbyqxmd.com/read/27729312/biomechanical-analysis-of-the-effect-of-congruence-depth-and-radius-on-the-stability-ratio-of-a-simplistic-ball-and-socket-joint-model
#19
L Ernstbrunner, J-D Werthel, T Hatta, A R Thoreson, H Resch, K-N An, P Moroder
OBJECTIVES: The bony shoulder stability ratio (BSSR) allows for quantification of the bony stabilisers in vivo. We aimed to biomechanically validate the BSSR, determine whether joint incongruence affects the stability ratio (SR) of a shoulder model, and determine the correct parameters (glenoid concavity versus humeral head radius) for calculation of the BSSR in vivo. METHODS: Four polyethylene balls (radii: 19.1 mm to 38.1 mm) were used to mould four fitting sockets in four different depths (3...
October 2016: Bone & Joint Research
https://www.readbyqxmd.com/read/27704603/novel-potential-marker-for-native-anteversion-of-the-proximal-femur
#20
Chesley F Durgin Iii, E Meade Spratley, Jibanananda Satpathy, William A Jiranek, Jennifer S Wayne
Identifying native femoral version from proximal femoral landmarks would be of benefit both for preoperative assessment as well as intraoperatively. To identify potential markers for femoral anteversion, an empirical framework was developed for orientation-independent analysis of the proximal femur from pelvic CT to allow for segmentation of the proximal femur into five constituent regions: Femoral head, femoral neck, greater trochanter, lesser trochanter and femoral shaft. The framework is based on the identification of differences in the radius of curvature at anatomic zones of transition between regions of the proximal femur, followed by non-linear geometric shape fitting...
October 5, 2016: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
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