Analysis of Functional Scoliosis by Means of an Anisotropic Beam Model of the Human Spine

1985 ◽  
Vol 107 (3) ◽  
pp. 281-285 ◽  
Author(s):  
L. Lindbeck
Keyword(s):  
Reasonable Agreement ◽  
Small Difference ◽  
Frontal Plane ◽  
Elastic Beam ◽  
Beam Model ◽  
Leg Length ◽  
X Ray ◽  
Human Spine ◽  
Anisotropic Elastic ◽  
Experimental Findings

An upright, muscle-relaxed human spine, suffering from a mild functional scoliosis, caused by a small difference in leg length, is modeled as an anisotropic, elastic beam. The lower end of the beam is built-in in a fixed body, i.e., the laterally tilted pelvis. The upper end is rigidly attached to a rigid body, i.e., the supported upper part of the trunk, which is supposed to move freely in the frontal plane. It is shown that the characteristic scoliotic curvature of the spine, observed on an X-ray picture, can be reproduced by means of buckling analysis of the beam model, using realistic values of geometric and loading parameters and a properly chosen bending stiffness, which is found to be in reasonable agreement with earlier experimental findings. The analysis also shows that the muscle-relaxed upright equilibrium position of the spine is mechanically unstable.

scholarly journals The occurrence rate and clinical application of Osteo-line on the femur neck

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Mingchen Zou ◽  
Haotian Wu ◽  
Shuangquan Yao ◽  
Dong Ren ◽  
Song Liu ◽  
...  
Keyword(s):  
Clinical Application ◽  
Visual Inspection ◽  
Occurrence Rate ◽  
Control Group ◽  
Leg Length ◽  
X Ray ◽  
The Third ◽  
Femur Neck ◽  
Medical University ◽  
Experimental Group

Abstract Background This study was done to observe the incidence of Osteo-line on the femur neck and to explore the clinical application of Osteo-line in osteotomy. Methods Eighty-nine adult femur specimens were selected to observe the incidence of Osteo-line on the femur neck. From August 2015 to January 2019, a total of 278 patients who completed unilateral hip arthroplasty at the Third Hospital of Hebei Medical University were retrospectively included. Patients who accepted osteotomy via Osteo-line on the femur neck were defined as the experimental group (n = 139), and patients who accepted osteotomy via traditional method (The femoral distance 1.5 cm above the trochanter was retained for osteotomy by visual inspection.) were defined as the control group (n = 139). According to the postoperative pelvic X-ray, Photoshop was used to evaluate the leg length discrepancy (LLD) by the CFR-T-LT method. Results Among the 89 specimens, the incidence of anterior Osteo-line was 75.28%, and the incidence of posterior Osteo-line was 100%. According to the clinical application results, the incidence of anterior Osteo-line on the femur neck was 80%, and the incidence of posterior Osteo-line was 100%. The Osteo-line was clearer than those on the femoral specimens. Twenty-six cases had LLD greater than 1 cm (9.29%), including 2 cases in the experimental group and 24 cases in the control group. The average postoperative LLD in the experimental group (0.19 ± 0.38 mm) was significantly shorter than in the control group (0.54 ± 0.51 mm)(P = 0.005). Conclusion The incidence of Osteo-line on the femur neck was high, and patients who accepted osteotomy via Osteo-line on the femur neck can achieve shorter postoperative LLD than the control group.

scholarly journals USE CAUTION WHEN ASSESSING PRE-OPERATIVE LEG LENGTH DISCREPANCY IN PEDIATRIC PATIENTS WITH ANTERIOR CRUCIATE LIGAMENT INJURIES

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0028
Author(s):  
Lindsay M. Schlichte ◽  
Peter D. Fabricant ◽  
Christine Goodbody ◽  
Daniel W. Green
Keyword(s):  
Anterior Cruciate Ligament ◽  
Pediatric Patients ◽  
Cruciate Ligament ◽  
Weight Bearing ◽  
Acl Injury ◽  
Leg Length ◽  
Full Extension ◽  
X Ray ◽  
Length Discrepancy ◽  
Anterior Cruciate

Background: Pre- and post-operative standing hip to ankle radiography is critical for monitoring potential post-operative growth arrest and resultant length and angular deformities after pediatric anterior cruciate ligament (ACL) reconstruction. During acquisition of pre-operative standing alignment radiographs, it is possible that patients are lacking full extension, not weight bearing comfortably, or leaning resulting in inaccurate measurements. Purpose: This study aims to assess both pre- and post-operative radiographic measurements to assess if the standing pre-operative x-ray is a accurate and reliable source for baseline measurements. Methods: We retrospectively reviewed prospectively collected pre-operative and first post-operative full-length hip-to-ankle radiographs in a cohort of skeletally immature athletes who presented with an acute ACL injury and underwent subsequent surgical reconstruction. Initially, leg length discrepancy for 25 patients was measured by 3 orthopedic surgeons (top of femoral head to center of tibial plafond). The intraclass correlation was almost perfect (ICC (2,1) = .996) therefore, 1 surgeon measured the remaining 94 radiographs. Measurements for both the injured and uninjured legs were obtained for comparison and surgeons were blinded to the injured side. Results: A total of 119 pediatric patients (mean age 13.4, range 7-14 years) were included (83 males and 36 females). Patient were categorized as either having ≥5mm, ≥10mm, or ≥15mm LLD on pre-operative standing x-ray. Sixty-two patients (52%) were found to have a pre-operative LLD ≥ 5mm. Forty-one (66%) of these patients tore their ACL on the limb measuring shorter. At 6 month post-operative standing x-ray, 35 patients (56%) resolved to ≤5mm LLD. Eighteen patients had a pre-operative LLD of ≥ 10mm. At 6 month post-operative standing x-ray, 13 (72%) patients resolved to ≤5mm LLD. Five patients had a pre-operative LLD of ≥ 15mm. At 6 month post-operative standing x-ray, 4 (80%) resolved ≤5mm. All patients with a pre-operative LLD of ≥ 13mm had sustained an ACL injury on the limb measuring shorter Conclusion: Of the pediatric ACL patients initially presenting with a pre-operative LLD of ≥ 10mm, 72% demonstrated apparent correction of their LLD on their 6 month standing x-ray. This high rate of LLD pre-operatively but not post operatively calls into question the accuracy of pre-operative standing alignment radiographs for patients after an ACL tear. Surgeons and radiology technicians should be aware of injured patients potentially lacking full extension, leaning, or not weight bearing comfortably, and should consider delaying preoperative radiographic length and alignment analysis until after the patient is able to fully straighten the injured knee and weight bear comfortably.

scholarly journals Determination of thermodynamic stability of FeB monoboride

2019 ◽  
Vol 27 (2) ◽  
pp. 69-76
Author(s):  
N. Yu. Filonenko ◽  
A. N. Galdina
Keyword(s):  
Thermodynamic Stability ◽  
Boron Content ◽  
Boron Concentration ◽  
Cast Alloy ◽  
Thermodynamic Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Expansion ◽  
Experimental Findings

In this paper we investigate the phase composition and phase transformations in the Fe-B system alloys with boron content in the range of 9.0–15.0 wt.%. We use microstructural, X-ray diffraction, differential thermal and durometric analyzes to determine the physical properties of the alloys. The experimental findings show that in the as-cast alloy structure there is Fe5B3 phase in small quantities along with FeB monoboride and Fe2B boride. The Fe5B3 phase is formed as a result of the peritectic reaction L+FeB→Fe5B3 at the temperature of 1680 K. The eutectic transformation L→Fe5B3 +Fe2B occurs in the boron concentration range of 8.8–10.5 wt.%. After annealing of the Fe-B alloys at the temperature of 1473 K and cooling with the rate of 102 K/s we observe the occurring of the Fe5B3 phase. To spot an opportunity of the secondary monoboride formation in the alloys under consideration, we calculate the thermodynamic characteristics of stability of the system. Accounting for the contribution of the first degree approximation of high-temperature expansion of thermodynamic potential of FeB iron monoboride in a Fe-B binary alloy enables us to study its thermodynamic stability. It is shown that stability decrease of FeB at 1423 K allows suggesting that at this temperature the phase transformation occurs and this fact correlates to the differential thermal analysis results.

IX. Nucleinsäuregehalt und Nucleinsäuresynthese nach Röntgenbestrahlung

1966 ◽  
Vol 21 (10) ◽  
pp. 960-966 ◽  
Author(s):  
Yasuhiko Takamori ◽  
Ernst-Randolf Lochmann ◽  
Wolfgang Laskowski
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Small Difference ◽  
Dry Weight ◽  
Nucleic Acid Content ◽  
X Rays ◽  
X Ray ◽  
Dna And Rna ◽  
High Doses ◽  
Different Doses

The amount of DNA and RNA per dry weight as well as the rate of RNA synthesis was determined in a series of almost isogenic and homozygous Saccharomyces strains of different ploidy which had irradiated with different doses of X-rays.It was found that the RNA content per dry weight showed only a small decrease after irradiation even with high doses. The decrease in the DNA content after irradiation is larger, and it is already maximal at the smallest X-ray dose tested (75 krad) . No further decrease could be observed even after application of 225 krad.The RNA synthesis is much more radioresistant in all strains tested (haploid-hexaploid) than the colony forming ability. X-ray doses which reduce the colony forming ability of the cells to less than 1% lead to a reduction of the RNA synthesis of only about 50 per cent. The inactivation of RNA synthesis increases with increasing irradiation doses and increasing incubation time after irradiation.There was only a small difference in the radiosensitivity of the synthesis of soluble or ribosomal RNA.Genetic effects on the radiation inactivation of the colony forming ability, previously described as “aα-effect” and “AS-effect”, show no influence on the radiosensitivity of cellular nucleic acid content and synthesis.

scholarly journals First Tarsometatarsal Joint Shape and Orientation

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0020
Author(s):  
Cesar de Cesar Netto ◽  
Jackson Staggers ◽  
Walter Smith ◽  
Sung Lee ◽  
Sierra Phillips ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Joint Angle ◽  
Frontal Plane ◽  
Cadaveric Specimen ◽  
X Ray ◽  
Horizontal Orientation ◽  
Medial Cuneiform ◽  
Flat Shape ◽  
Fresh Frozen ◽  
Joint Shape

Category: Bunion Introduction/Purpose: Studies have demonstrated that patients with hallux valgus (HV) deformities have increased mobility in the first tarsometatarsal (TMT) joint. Anatomical factors widely considered to play a role in the instability are shape and frontal plane orientation of the joint. An oblique rather than horizontal orientation of the articular surfaces and a round shape, rather than a flat shape, are believed to predispose to the deformity. The purpose of this study was to assess whether the shape and angulation of the first TMT joint are affected by the positioning of the foot and orientation of the x-ray beam. Methods: Ten adult above knee fresh frozen cadaveric specimens were used, with a mean age of 79.9 (range, 54-88) years. There were no clinical forefoot deformities noted in any of the feet. One of the specimens had moderate ankle arthritis and one had a mild cavus-varus. A radiolucent loading apparatus was built that, allowing neutral positioning of a plantigrade foot and controlled angulation of 5o, 10 o, 15o and 20o in dorsiflexion, plantarflexion, inversion and eversion. Fluoroscopic images were obtained of each cadaveric specimen in all seventeen different positions, with the x-ray beam perpendicular to the floor and aiming to the base of the 1st metatarsal. Two blinded orthopaedic surgeons independently measured the 1st tarsometatarsal (TMT) joint angle and graded the distal articular cartilage of the medial cuneiform as flat or curved. Readers also graded the image quality into assessing the joint into “Low”, “Intermediate” and “Good”. Results: 1st TMT joint angle was 112.92o ± 6.89o. Values were significantly different between cadaveric specimens (p<.0001). There was a tendency for increased valgus angulation of the joint in images positioned in neutral, plantarflexion and inversion and decreased valgus angulation with dorsiflexion and eversion.Regarding the shape of the distal articular cartilage of the medial cuneiform, joints with flat configuration showed significantly increased mean 1st TMT joint angle when compared to curved surfaces (115.9o vs. 110.7o, p<.0001). In 8 out of 10 of the cadaveric specimens (80%) the shape of the 1st TMT joint changed between curved or flat configuration depending on the positioning of the foot. In only 2/10 (20%) the joint configuration remained the same for all different positions (one flat and one curved). Conclusion: Our cadaveric study found that the shape and angulation of the first TMT joint is affected by the positioning of the foot and orientation of the x-ray beam. Clinical usefulness of the 1st TMT radiographic anatomical characteristics is limited and should not influence in the treatment of patients with possible instability the first tarsometatarsal (TMT) joint.

Dynamical Theory for Simultaneous X-Ray Diffraction

1966 ◽  
Vol 10 ◽  
pp. 67-79
Author(s):  
P. Penning
Keyword(s):  
Experimental Data ◽  
Plane Wave ◽  
Quantitative Data ◽  
Reasonable Agreement ◽  
Dynamical Theory ◽  
Inversion Symmetry ◽  
Surprising Result ◽  
X Ray Diffraction ◽  
Wave Fields ◽  
X Ray

AbstractComplete dynamical solutions for three coupled plane-wave components in crystal structures with inversion symmetry have been found. After reviewing briefly the dynamical solutions for wave fields with two coupled plane-wave components, the results for the three-beam case are discussed in qualitative terms. Attention is paid to singular points and lines on the ω-surface, and to the attenuation of the mode-intensity because of absorption. The most surprising result is that in the case one of the reflections is forbidden (Umweganregung) the absorption is reduced in comparison with the adjoining two-beam cases. Experimental data are in reasonable agreement with the theory. Quantitative data are presented for a few three-beam cases of simultaneous diffraction of Cu Kα. radiation in germanium.

scholarly journals The location of the grounding zone of Evans Ice Stream, Antarctica, investigated using SAR interferometry and modelling

2009 ◽  
Vol 50 (52) ◽  
pp. 35-40 ◽  
Author(s):  
Helena J. Sykes ◽  
Tavi Murray ◽  
Adrian Luckman
Keyword(s):  
Stream Flow ◽  
Elastic Beam ◽  
Tidal Height ◽  
Sar Interferometry ◽  
Beam Model ◽  
West Antarctica ◽  
Tidal Model ◽  
Tidal Forcing ◽  
Ice Stream ◽  
Grounding Line

AbstractEvans Ice Stream, West Antarctica, has five tributaries and a complex grounding zone. The grounding zone of Evans Ice Stream, between the landward and seaward limits of tidal flexing, was mapped using SAR interferometry. The width of the mapped grounding zone was compared with that derived from an elastic beam model, and the tidal height changes derived from interferometry were compared with the results of a tidal model. Results show that in 1994 and 1996 the Evans grounding zone was located up to 100 km upstream of its location in the BEDMAP dataset. The grounding line of Evans Ice Stream is subjected to 5 m vertical tidal forcing, which would clearly affect ice-stream flow.

5,6,7,8-Tetrahydronaphthalen-1-amine as Precursor for Thiazolidi­nones and Benzothiazepinones: Synthesis and Atropisomeric Relationship

Synthesis ◽  
2017 ◽  
Vol 49 (23) ◽  
pp. 5167-5175 ◽  
Author(s):  
Bruna Drawanz ◽  
Georgia Zimmer ◽  
Leticia Rodrigues ◽  
Andressa Nörnberg ◽  
Manfredo Hörner ◽  
...  
Keyword(s):  
Small Difference ◽  
Mercaptoacetic Acid ◽  
X Ray Diffraction ◽  
Ring Plane ◽  
One Pot ◽  
X Ray ◽  
Nmr Techniques ◽  
The One ◽  
Electron Donating Groups ◽  
Weak Electron

The one-pot reaction of 5,6,7,8-tetrahydronaphthalen-1-amine, mercaptoacetic acid, and arenealdehydes having strong and weak electron-withdrawing groups gave the corresponding 1,3-thiazolidin-4-ones (47–70%). When arenealdehydes bearing strong and weak electron-donating groups were used as precursors, the 1,4-benzothiazepin-2-ones were obtained (30–72%) by p-TsOH catalysis. All compounds are unknown and were characterized by GC-MS and NMR techniques, and available crystals by X-ray diffraction studies. The atropisomerism phenomenon was observed in several 1,3-thiazolidin-4-ones as confirmed by VTNMR method. The Tc was established as 332 K and the energy required for the interconversion of one atrop­isomer into another is around 16.8 kcal·mol–1. Chemical quantum calculation and NOESY displayed that more stable isomer has the tetrahydro­naphthalene portion below the five-ring plane. Only a small difference between isomers (–0.21 to –0.84 kcal·mol–1) was observed by calculated energy.

1,2-Di(silyl)benzene and 1,4-Dibromo-2,5-di(silyl)benzene

1994 ◽  
Vol 49 (8) ◽  
pp. 1036-1040 ◽  
Author(s):  
Robert Schröck ◽  
Alexander Sladek ◽  
Hubert Schmidbaur
Keyword(s):  
Methanesulfonic Acid ◽  
Intermediate Compound ◽  
Molecular Structures ◽  
High Yield ◽  
Electronic Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Yields ◽  
Experimental Findings ◽  
Silylation Reaction

1,2-Di(silyl)benzene (3), has been prepared in a three-step process starting with the reac­tion of 1,2-dibromobenzene and p-tolyl(chloro)silane with magnesium in tetrahydrofuran. which affords 1,2-bis(p-tolylsilyl)benzene (1) as a stable high-yield intermediate. Compound 1 has been converted into 1,2-bis(trifluoromethanesulfonatosilyl)benzene (2) with trifluoro- methanesulfonic acid, and finally into 3 by reduction with lithiumaluminiumhydride, both again in high yields. - In an attempt to prepare 1,2,4,5-tetra(silyl)benzene in an analogous way. only the bis-silylated species could be obtained (from 1,2,4,5-C6H2Br4. p-MeC6H4SiClH2 and Mg powder: 1,4-dibromo-2,5-bis(p-tolylsilyl)benzene. 4, and 1,4-dibromo-2,5-di(silyl)- benzene, 6, via 1,4-dibromo-2,5-bis(trifluoromethanesulfonatosilyl)benzene, 5). The crystal structures of compounds 4 and 6 have been determined by X-ray diffraction. The results indicate no steric hindrance in these molecules and it is thus not obvious from the molecular structures why the silylation reaction does not proceed any further to give the tetrasilylated benzene derivatives. Electronic effects have to be invoked to rationalize the experimental findings.

Validation of aGeant4model of the X-ray fluorescence microprobe at the Australian Synchrotron

2015 ◽  
Vol 22 (2) ◽  
pp. 354-365 ◽  
Author(s):  
Matthew Richard Dimmock ◽  
Martin Daly de Jonge ◽  
Daryl Lloyd Howard ◽  
Simon Alexander James ◽  
Robin Kirkham ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Low Energy ◽  
Beam Model ◽  
Compton Continuum ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
Simulation Process ◽  
Beryllium Window ◽  
Spectral Distributions ◽  
Energy Physics

AGeant4Monte Carlo simulation of the X-ray fluorescence microprobe (XFM) end-station at the Australian Synchrotron has been developed. The simulation is required for optimization of the scan configuration and reconstruction algorithms. As part of the simulation process, a Gaussian beam model was developed. Experimental validation of this simulation has tested the efficacy for use of the low-energy physics models inGeant4for this synchrotron-based technique. The observed spectral distributions calculated in the 384 pixel Maia detector, positioned in the standard back-scatter configuration, were compared with those obtained from experiments performed at three incident X-ray beam energies: 18.5, 11.0 and 6.8 keV. The reduced χ-squared (\chi^{2}_{\rm{red}}) was calculated for the scatter and fluorescence regions of the spectra and demonstrates that the simulations successfully reproduce the scatter distributions. Discrepancies were shown to occur in the multiple-scatter tail of the Compton continuum. The model was shown to be particularly sensitive to the impurities present in the beryllium window of the Maia detector and their concentrations were optimized to improve the \chi^{2}_{\rm{red}} parameterization in the low-energy fluorescence regions of the spectra.

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