Joint moments during downhill and uphill walking of a person with transfemoral amputation with a hydraulic articulating and a rigid prosthetic ankle—a case study

Introduction: Functional characteristics of prosthetic ankle design may facilitate sloped walking for transfemoral amputees. The aim of the current case-study was to analyse the effects of a rigid vs. a hydraulically articulating ankle component on the biological joint moments of a transfemoral amputee during downhill, uphill and level walking. Methods: The gait of one unilateral transfemoral amputee, using the same prosthetic foot with rigid and hydraulic ankle components, was analysed and compared to a control group of 18 able-bodied participants. Kinematic and kinetic data were recorded at self-selected walking speed on a sloped ramp with inclinations of -12°, -4° (downhill), 0° (level), +4° and +12° (uphill). Results: The slope influenced lower limb joint moments similarly in both able-bodied and transfemoral participants. The effect of altering ankle movement through exchanging prosthetic ankle componentry was most acutely seen at the hip joint of the residual limb. The use of a hydraulic ankle joint component resulted in decreased mean hip joint extension and flexion moments of up to 92% and 48% respectively in the residual limb when compared to using the rigid ankle joint component, respectively. Conclusion: During sloped walking, the use of a hydraulically articulating vs. rigid ankle joint component reduced the joint moments observed at the hip joint of the residual limb in a unilateral transfemoral amputee. This indicates a benefit for transfemoral amputees as the increased ankle function reduces the moment producing requirements of the hip joint which may result in decreased energy consumption and subsequently, a more efficient gait

Acute forces required for datal compression asphyxia: A biomechanical model and historal comparisons

Background Fatalities from acute compression have been reported with soft-drink vending machine tipping, motor vehicle accidents, and trench cave-ins. A major mechanism of such deaths is flail chest but the amount of force required is unclear. Between the range of a safe static chest compression force of 1000 N (102 kg with earth gravity) and a lethal dynamic force of 10–20 kN (falling 450 kg vending machines), there are limited quantitative human data on the force required to cause flail chest, which is a major correlate of acute fatal compression asphyxia. Methods We modeled flail chest as bilateral fractures of six adjacent ribs. The static and dynamic forces required to cause such a ribcage failure were estimated using a biomechanical model of the thorax. The results were then compared with published historical records of judicial “pressing,” vending machine fatalities, and automobile safety cadaver testing. Results and conclusion The modeling results suggest that an adult male requires 2550 ± 250 N of chest-applied distributed static force (260 ± 26 kg with earth gravity) or 4050 ± 320 N of dynamic force to cause flail chest from short-term chest compression

First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio

Study of bound states in Be-10 by one neutron removal reactions of Be-11

The bound states of Be-10 have been studied by removing single neutrons from Be-11 nuclei. A 2.8 MeV u(-1) beam of Be-11 was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in Be-10 were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in Be-10. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2(2)(+) state is observed, which which may indicate the presence of multi-step processes at our beam energy.Peer reviewe

Restoring the valence-shell stabilization in Nd-140

A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd-140 using the multistep Coulomb-excitation code GOSIA. The absolute M1 strengths, B(M1; 2(2)(-) -> 2(1)(+)) = 0.033(8)mu(2)(N), B(M1 ; 2(3)(+) -> 2(1)(+)) = 0.26(-0.10)(+0.11)mu(2)(N), and B(M1; 2(4)+ -> 2(1)(+)) <0.04 mu(2)(N) identify the 2(3)(+) state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd-140. The degree of F-spin mixing in Nd-140 was quantified with the determination of the mixing matrix element VF-mix <7(-7)(-13) keV.Peer reviewe

Rb-37(97)60 : The Cornerstone of the Region of Deformation around A similar to 100

Excited states of the neutron-rich nuclei Rb-97,Rb- 99 were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of Rb-97 as being built on the pi g(9/2) [431] 3/2(+) Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N = 60 and rotational bands above. The present study defines the limits of the deformed region around A similar to 100 and indicates that the deformation of Rb-97 is essentially the same as that observed well inside the deformed region. It further highlights the power of the Coulomb-excitation technique for obtaining spectroscopic information far from stability. The Rb-99 case demonstrates the challenges of studies with very short-lived postaccelerated radioactive beams.Peer reviewe

High-sensitivity study of levels in Al-30 following beta decay of Mg-30

gamma-ray and fast-timing spectroscopy were used to study levels in Al-30 populated following the beta(-) decay of Mg-30. Five new transitions and three new levels were located in Al-30. A search was made to identify the third 1(+) state expected at an excitation energy of similar to 2.5 MeV. Two new levels were found, at 3163.9 and 3362.5 keV, that are firm candidates for this state. Using the advanced time-delayed (ATD) beta gamma gamma (t) method we have measured the lifetime of the 243.8-keV state to be T-1/2 = 15(4) ps, which implies that the 243.8-keV transition is mainly of M1 character. Its fast B(M1; 2(+) -> 3(+)) value of 0.10(3) W.u. is in very good agreement with the USD shell-model prediction of 0.090 W.u. The 1801.5-keV level is the only level observed in this study that could be a candidate for the second excited 2(+) state.Peer reviewe

The observation of vibrating pear-shapes in radon nuclei (vol 10, 2473, 2019)

An amendment to this paper has been published and can be accessed via a link at the top of the paper