Computational Modeling of Hip Replacement Surgery: Total Hip Replacement vs. Hip Resurfacing

The motivation of the present work is the computational simulation of hip replacement surgery by means of a finite element approach based on open system thermodynamics. Its key feature is a non-constant material density, which is allowed to adapt with respect to changes in the mechanical loading environment. From a computational point of view, the density is treated as an internal variable. Its evolution is governed by a first order rate equation, the balance of mass, which is enhanced by an additional mass production term to account for growth. An implicit Euler backward scheme is suggested for its time discretization. The algorithmic determination of the material density based on a local Newton iteration is presented. To ensure quadratic convergence of the global Newton Raphson solution scheme, a consistent linearization of the discrete algorithmic equations is carried out. Finally, two alternative medical techniques in hip arthritis are compared, the conventional total hip replacement strategy and the more recent hip resurfacing technology. The result of the suggested remodeling algorithm is shown to agree remarkably well with clinically observed phenomena

Tools for Quality Testing of Batches of Artifacts: The Cryogenic Thermometers for the LHC

In the processing of data series, such as in the case of the resistance R vs. temperature T calibrations of the thermometers (several thousands) necessary for the LHC new accelerator at CERN, it is necessary to use automatic methods for determining the quality of the acquired data and the degree of uniformity of the thermometer characteristics, that are of the semiconducting type. In addition, it must be determined if the calibration uncertainties comply with the specifications in the wide temperature range 1,6 - 300 K. Advantage has been taken of the fact that these thermometers represent a population with limited variability, to apply a Least Squares Method with Fixed Effect. This allows to fit the data of all the thermometers together, by taking into account the individuality of each thermometer in the model as a deviation from one of them taken as reference Ri = f(Ti) + bk0 + bk1 g(Tki) + bk1g(Tki)2 + ... where f(Ti) is the model valid for all i data and all k thermometers, while the subsequent part is the "fixed effect" model for the k-th thermometer, where g(T) is a suitable function of T. This method is shown in the paper applied to different stages of the data processing. First, for efficient compensation for the thermal drift occurring during acquisition, robust against the occurrence of outliers. Second, for detection of clusters of thermometers with inherently different characteristics. Finally, for optimisation of the calibration-point distribution

Cryogenic Thermometer Calibration Facility at CERN

A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of Rhodium-Iron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC). LabVIEW is used both as the PLC operator interface and for configuring and reading the thermometric data sampled by the higher accuracy laboratory equipment. The isothermal support onto which the thermometers are mounted is thermally anchored through the wiring to a helium bath. The calibration procedure begins once the temperature of the support is stabilized. Measured data is presented and it is possible to infer that the absolute accuracy that can be obtained is better than ± 5 mK for the full temperature range

An Unusual Presentation of Recurrent Squamous Cell Carcinoma

Introduction: Cutaneous squamous cell carcinoma (cSCC) is the second most common type of skin cancer with excellent outcomes after surgical removal in most cases. However, local recurrence occurs in about 4.6% of cases and is a sign of aggressive biologic behavior. Here, we present a case of recurrent SCC with unusual clinical features. Case Presentation: A 65-year old male with past medical history of untreated prostate cancer and anal cancer status post chemoradiation presented with a nonhealing wound on the right lateral hip. He had previously undergone excision of a squamous cell carcinoma in this area, followed by Mohs surgery due to local recurrence. After both procedures, clear margins were noted histologically. On exam of the right hip there was a large wound with granulation tissue and grouped grey papules and vesicles coalescing into plaques along the posterior edge of the wound which were rapidly progressive. Due to the rapid spread and vesicular nature, infection was initially favored, but the patient did not improve despite treatment with antibiotics and antivirals. The lesion was subsequently biopsied showing moderately differentiated cSCC with high grade features. The patient refused palliative radiation, and cemiplimab, a PD-1 inhibitor, is being initiated. Discussion: Local recurrence is considered a high-risk feature for cSCC. The threshold for biopsy in cases of possible recurrent cSCC is low, especially given that the clinical presentation can vary, such as the unusual appearance in our case. A multidisciplinary approach is critical in the management of such patients to reduce morbidity and mortality.https://scholarlycommons.henryford.com/merf2020caserpt/1005/thumbnail.jp

REDUCING SUGAR CONTENT IN SIWALAN ROOMIE (Borassus flabellifer L) BEFORE COOKING AND LIQUID BROWN SUGAR AFTER COOKING

Sugar reduction is one of the essential macronutrients used as energy sources. High levels of sugar reduction in food can increase the sweet taste of these foodstuffs. However, the consumption of high sugar food can cause diabetes mellitus. The purpose of this study is to increase the economic value of liquid palm sugar (Borassus flabellifer L) and opportunities as a preservative in the food industry. This research used quantitative descriptive methods. The results showed that the level of sugar reduction in siwalan liquid brown sugar (Borassus flabellifer L) was 15.65%, the water content in the liquid palm sugar sample (Borassus flabellifer L) is 26.78%, and the temperature of the liquid brown sugar after cooking is 230C. The effect of heat or temperature on cooking also causes physical changes in liquid brown sugar such as caramel formation, color and flavour

Influence of Thermal Cycling on Cryogenic Thermometers

The stringent requirements on temperature control of the superconducting magnets for the Large Hadron Collider (LHC), impose that the cryogenic temperature sensors meet compelling demands such as long-term stability, radiation hardness, readout accuracy better than 5 mK at 1.8 K and compatibility with industrial control equipment. This paper presents the results concerning long-term stability of resistance temperature sensors submitted to cryogenic thermal cycles. For this task a simple test facility has been designed, constructed and put into operation for cycling simultaneously 115 cryogenic thermometers between 300 K and 4.2 K. A thermal cycle is set to last 71/4 hours: 3 hours for either cooling down or warming up the sensors and 1 respectively 1/4 hour at steady temperature conditions at each end of the temperature cycle. A Programmable Logic Controller (PLC) drives automatically this operation by reading 2 thermometers and actuating on 3 valves and 1 heater. The first thermal cycle was accomplished in a temperature calibration facility and all the thermometers were recalibrated again after 10, 25 and 50 cycles. Care is taken in order not to expose the sensing elements to moisture that can reputedly affect the performance of some of the sensors under investigation. The temperature sensors included Allen-Bradley and TVO carbon resistors, Cernox, thin-film germanium, thin-film and wire-wound Rh-Fe sensors

Can Weakness in End-Range Plantar Flexion After Achilles Tendon Repair Be Prevented?

Background: Disproportionate end-range plantar flexion weakness, decreased passive stiffness, and inability to perform a heel rise on a decline after Achilles tendon repair are thought to reflect increased tendon compliance or tendon lengthening. Since this was first noted, we have performed stronger repairs and avoided stretching into dorsiflexion for the first 12 weeks after surgery. Hypothesis: Using stronger repairs and avoiding stretching into dorsiflexion would eliminate end-range plantar flexion weakness and normalize passive stiffness. Study Design: Case series; Level of evidence, 4. Methods: Achilles repairs with epitendinous augmentation were performed on 18 patients. Plantar flexion torque, dorsiflexion range of motion (ROM), passive joint stiffness, and standing single-legged heel rise on a decline were assessed at 43 ± 24 months after surgery (range, 9 months to 8 years). Maximum isometric plantar flexion torque was measured at 20° and 10° of dorsiflexion, neutral position, and 10° and 20° of plantar flexion. Passive dorsiflexion ROM was measured with a goniometer. Passive joint stiffness was computed from the increase in passive torque from 10° to 20° of dorsiflexion. Tendon thickness was measured by use of digital calipers. Plantar flexion electromyographic (EMG) data were recorded during strength and functional tests. Analysis of variance and chi-square tests were used to assess weakness and function. Results: Marked weakness was evident on the involved side at 20° of plantar flexion (deficit, 26% ± 18%; Conclusion: The use of stronger repair techniques and attempts to limit tendon elongation by avoiding dorsiflexion stretching did not eliminate weakness in end-range plantar flexion. EMG data confirmed that end-range weakness was not due to neural inhibition. Physiological changes that alter the force transmission capability of the healing tendon may be responsible for this continued impairment. This weakness has implications for high-demand jumping and sprinting after Achilles tendon repair

Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS

Golden SmS is a paramagnetic, mixed-valence system with a pseudogap. With increasing pressure across a critical pressure Pc, the system undergoes a discontinuous transition into a metallic, anti-ferromagnetically ordered state. By using a combination of thermodynamic, transport, and magnetic measurements, we show that the pseudogap results from the formation of a local bound state with spin singlet. We further argue that the transition Pc is regarded as a transition from an insulating electron-hole gas to a Kondo metal, i.e., from a spatially bound state to a Kondo virtually bound state between 4f and conduction electrons.Comment: 5 pages, 5 figure

Vectorial dissipative solitons in vertical-cavity surface-emitting Lasers with delays

We show that the nonlinear polarization dynamics of a vertical-cavity surface-emitting laser placed into an external cavity leads to the formation of temporal vectorial dissipative solitons. These solitons arise as cycles in the polarization orientation, leaving the total intensity constant. When the cavity round-trip is much longer than their duration, several independent solitons as well as bound states (molecules) may be hosted in the cavity. All these solutions coexist together and with the background solution, i.e. the solution with zero soliton. The theoretical proof of localization is given by the analysis of the Floquet exponents. Finally, we reduce the dynamics to a single delayed equation for the polarization orientation allowing interpreting the vectorial solitons as polarization kinks.Comment: quasi final resubmission version, 12 pages, 9 figure