Spinal Muscular Atrophy from Northern Iran: A Clinical and Genetic Spectrum of Ten Patients

AbstractObjectiveAutosomal recessive spinal muscular atrophy (SMA) is, after cystic fibrosis, the second most common fatal monogenic disorder and the second most common hereditary neuromuscular disease after duchenne dystrophy. The disease is characterized by degeneration of anterior horn cells leading to progressive paralysis with muscular atrophy. Depending on the clinical type (Werdnig- Hoffmann = type I, intermediate form = type II, Kugelberg-Welander = type III), some workers also have delineated an adult form of SMA (SMA type 4).SMA causes early death or increasing disability in childhood. The aim of this investigation was to describe the clinical findings of patients with spinal muscular atrophy (SMA) with survival motor neuron (SMN) gene deletion.Materials & methodsThis is a descriptive study conducted on 10 patients of SMA, confirmed by deletion of the SMN gene. All 10 patients had symmetrical muscle weakness, which was diffuse in those with onset of symptoms up to 1 months of age, and either proximal or predominant in lower limbs. Frequency determination of positive clinical and laboratory data was done according to revised diagnostic criteria.ResultsIt was found that all patients with SMA had homozygous deletions of exons 7 and 8 of the survival motor neuron 1 (SMN1) gene, which is one of the candidate genes identified within 5q13. Fasciculations, atrophy and decreased DTR were frequent findings. Laboratory metabolic tests and all brain CT scans were normal. EMG and NCV findings, all showed normal motor and Sensory NCV and denervation of muscles of upper and lower extremities were compatible with a diagnosis of spinal muscular atrophy.ConclusionOur results confirm that SMN1 copy number analysis is an important parameter for identification of couples at risk of having a child affected with SMA and reduces unwarranted prenatal diagnosis for SMA

A new benchmark problem for electromagnetic modelling of superconductors: The high-T <inf>c</inf>superconducting dynamo

The high-Tc superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. A critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom (DOFs), tolerance settings and the approximate time taken per cycle for each model

Modeling the charging process of a coil by an HTS dynamo-type flux pump

The high-Tc superconducting (HTS) dynamo exploits the nonlinear resistivity of an HTS tape to generate a DC voltage when subjected to a varying magnetic fie ld. This leads to the so-called flux pumping phenomenon and enables the injection of DC current into a superconducting coil connected to the dynamo without current leads. In this work, the process of charging a coil by an HTS dynamo is examined in detail using two numerical models: the Minimum Electromagnetic Entropy Production and the segregated H-formulation fi nite element model. The numerical results are compared with an analytical method for various airgaps and frequencies. Firstly, the I-V curves of the modeled HTS dynamo are calculated to obtain the open-circuit voltage, short-circuit current and internal resistance. Afterward, the process of charging a coil by the dynamo including the charging current curve and its dynamic behavior are investigated. The results obtained by the two models show excellent quantitative and qualitative agreement with each other and with the analytical method. Although the general charging process of the coil can be obtained from the I-V curve of the flux pump, the current ripples within a cycle of dynamo rotation, which can cause ripple AC loss in the HTS dynamo, can only be captured via the presented models

A new benchmark problem for electromagnetic modelling of superconductors: The high-T csuperconducting dynamo

The high-T c superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. Finally, a critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: Number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom, tolerance settings and the approximate time taken per cycle for each model. This benchmark and the results contained herein provide researchers with a suitable framework to validate, compare and optimise their own methods for modelling the HTS dynamo

Erratum: A new benchmark problem for electromagnetic modelling of superconductors: The high-Tc superconducting dynamo (Superconductor Science and Technology (2020) 33 (105009) DOI: 10.1088/1361-6668/abae04)

Since publication, we have realized that the results from the minimum electromagnetic entropy (MEMEP) method (see section 3.3 in the original paper [1]) used a different voltage definition, causing a slight discrepancy with the results obtained from the other methods in figures 3 and 4. Instead of Veq (t) = −LEave (t), as given by equation (5) in [1], we used −∆V(t) as defined by equation (22) in [2]: ∆V ≈ L· [∂tAav,J + Eave (J)] . Although both definitions result in the same DC voltage, the instantaneous signal differs, as shown in figure 1 in this corrigendum. Indeed, the used ∆V for the MEMEP method in [1] adds an extra contribution, ∂tAav,J, the vector potential due to the superconducting current. As a result, the new curve has much better qualitative and quantitative agreement with the waveforms calculated by the other methods shown in figure 3 of the original article [1]. In the original article [1], we also used the −∆V(t) definition above instead of Veq (t) to calculate the cumulative time-averaged equivalent voltage, defined from equation (6) in [1] as t Vcumul (t) = 1t Veq (t) dt. 0 The new results, using Veq (t) , present only small changes compared to the original calculations, as shown in figure 2 in this corrigendum. This curve also has very good qualitative and quantitative agreement with the waveforms calculated by the other methods, as shown in figure 4 in the original article [1]. The data related to the new calculations for this corrigendum are available at the University of Cambridge data repository (https://doi.org/10.17863/CAM.60437)

Erratum: A new benchmark problem for electromagnetic modelling of superconductors: The high-T<inf>c</inf> superconducting dynamo (Superconductor Science and Technology (2020) 33 (105009) DOI: 10.1088/1361-6668/abae04)

Since publication, we have realized that the results from the minimum electromagnetic entropy (MEMEP) method (see section 3.3 in the original paper [1]) used a different voltage definition, causing a slight discrepancy with the results obtained from the other methods in figures 3 and 4. Instead of Veq (t) = −LEave (t), as given by equation (5) in [1], we used −∆V(t) as defined by equation (22) in [2]: ∆V ≈ L· [∂tAav,J + Eave (J)] . Although both definitions result in the same DC voltage, the instantaneous signal differs, as shown in figure 1 in this corrigendum. Indeed, the used ∆V for the MEMEP method in [1] adds an extra contribution, ∂tAav,J, the vector potential due to the superconducting current. As a result, the new curve has much better qualitative and quantitative agreement with the waveforms calculated by the other methods shown in figure 3 of the original article [1]. In the original article [1], we also used the −∆V(t) definition above instead of Veq (t) to calculate the cumulative time-averaged equivalent voltage, defined from equation (6) in [1] as t Vcumul (t) = 1t Veq (t) dt. 0 The new results, using Veq (t) , present only small changes compared to the original calculations, as shown in figure 2 in this corrigendum. This curve also has very good qualitative and quantitative agreement with the waveforms calculated by the other methods, as shown in figure 4 in the original article [1]. The data related to the new calculations for this corrigendum are available at the University of Cambridge data repository (https://doi.org/10.17863/CAM.60437)

A new benchmark problem for electromagnetic modelling of superconductors: The high-T <inf>c</inf>superconducting dynamo

The high-Tc superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet (PM) rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. Finally, a critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom (DOFs), tolerance settings and the approximate time taken per cycle for each model. This benchmark and the results contained herein provide researchers with a suitable framework to validate, compare and optimise their own methods for modelling the HTS dynamo

A new benchmark problem for electromagnetic modelling of superconductors: the high-Tc superconducting dynamo

The high-Tc superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet (PM) rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. Finally, a critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom (DOFs), tolerance settings and the approximate time taken per cycle for each model. This benchmark and the results contained herein provide researchers with a suitable framework to validate, compare and optimise their own methods for modelling the HTS dynamo