Reliability of 2D ultrasound imaging associated with transient ShearWave Elastography method to analyze spastic gastrocnemius medialis muscle architecture and viscoelastic properties

PurposeThe aim of the study was to assess the reliability of pennation angle (PA) and muscle thickness (MT) 2D measurements and of shear elastic modulus measurement, using ultrasound imaging (US). Those measurements were made on spastic gastrocnemius medialis muscle at rest and at maximal passive stretching, in post-stroke hemiplegic patients. The paretic side measurements were compared to non-paretic side.Material and methodsFourteen patients took part in 2 inter-session reliability experiments, realized at a 7 days interval by the same operator. The Aixplorer® Supersonic US scanner with the transient ShearWave Elastography (SWE) software was used. The stretching experiments were made manually and controlled by a goniometer.ResultsThe reliability of the 2D measurements was good. The coefficient of variation (CV) was 6.30% for MT measurement at rest, 6.40% and 8.26% for PA at rest and at maximal passive stretching respectively. The reliability of the shear elastic modulus measurement in the sagittal plane was good only at rest with a CV of 9.86%, versus 40.58% at stretching. None of the shear elastic modulus measurements in the axial plane were good. At rest, MT and PA were weaker on the paretic side (14.25±3.12mm and 17.32±5.10°) versus non-paretic side (16.30±3.19mm and 21.08±5.05°) (P<0.0001 and P=0.006). At rest, there was a small difference in the shear elastic modulus between the paretic side and the non-paretic side (5.40±1.67kPa versus 6.20±2.18kPa, P=0.041).DiscussionThis is the first description of muscle spastic structure using SWE with Supersonic Shear Imaging. 2D US associated with SWE shows promise in terms of muscular atrophy quantification and muscle histological quality assessment. These structural properties reflect some of the functional abilities regardless of motor control. It should enable further research on therapies, which impact muscle tissue quality, such as botulinum neurotoxin injections

Visible to near-infrared down-shifting in Tm3+ doped fluoride glasses for solar cells efficiency enhancement

In this paper, down-conversion of Tm3+ doped fluoride ZLAG glasses with composition of 70.2ZrF4–(23.4−x)LaF3–0.6AlF3–5.8GaF3–xTmF3 (x = 0.25, 0.5, 0.75, 1, 2, 3 and 5 mol%) were tested as encapsulation materials for solar cells. The current density – voltage (J-V) characterizations were performed under solar simulator irradiation. The influence of Tm3+ concentration on the mono crystalline silicon solar cells performances was investigated. A slight increase of the solar cell efficiency was observed in the case of fluoride ZLAG for Tm3+ doping concentrations up to 1 mol% Tm3+. Further increase of the Tm3+ concentration leads to a decrease of solar cell conversion efficiency as a result of concentration quenching

Rare-earth-activated glasses for solar energy conversion

The solar cells efficiency may be improved by better exploitation of the solar spectrum, making use of the down-conversion mechanism, where one high energy photon is cut into two low energy photons. The choice of the matrix is a crucial point to obtain an efficient down-conversion process with rare-earth ions. When energy transfer between rare earth ions is used to activate this process, high emission and absorption cross sections as well as low cut-off phonon energy are mandatory. In this paper we present some results concerning 70SiO2-30HfO2 glass ceramic planar waveguides co-activated by Tb3+/Yb3+ ions, fabricated by sol gel route using a top-down approach, and a bulk fluoride glass of molar composition 70ZrF4 23.5LaF3 0.5AlF3 6GaF3 co-activated by Pr3+/Yb3+ ion. Attention is focused on the assessment of the energy transfer efficiency between the two couples of rare earth ions in the different hosts

Studies on Pr3+–Yb3+ codoped ZBLA as rare earth down convertor glasses for solar cells encapsulation

The non-absorption of photons with energies below the bandgap (Eg) and the thermalization of photons with energies higher than Eg are the dominant loss processes of single-junction solar cells. Rare earth doped glasses give the opportunity to convert the incident photons wavelength and hence to increase or decrease their energies. The conversion of photons energies by “up or down conversion” leads to the possibility to increase the efficiencies of all classes of single-junction solar cells. Depending on the nature of doping materials, two low energy photons can be converted into one high-energy photon (up-conversion), or one high energy photon, can be converted into two low energy photons (down-conversion). In this paper, Pr3+–Yb3+ down-conversion co-doped ZBLA glasses were tested as encapsulation materials for silicon solar cells. The J–V characterizations were done under solar simulator irradiation. The influence of Yb3+ concentration on the solar cells performances was investigated, showing that an optimum value between 0.5 and 2 mol% conducts to an increase of the device efficiency comparing to mono-doped ZBLA material

NOD × 129.H2g7 Backcross Delineates 129S1/SvImJ-Derived Genomic Regions Modulating Type 1 Diabetes Development in Mice

OBJECTIVE: Introduction of genes targeted in 129/Sv embryonic stem (ES) cells into NOD mice brings about linked genes that may modulate type 1 diabetes. Our objective was to identify 129S1/SvJ non-MHC regions contributing type 1 diabetes resistance or susceptibility in backcross to NOD/LtJ. RESEARCH DESIGN AND METHODS: After congenic transfer of the NOD H2(g7) haplotype onto 129S1/Sv, 310 females were produced by NOD x (NOD x 129.H2(g7))F1 backcross (N2). A genome scan for quantitative trait locus (QTL) affecting clinical diabetes, age of diabetes onset, and insulitis severity was performed using subphenotype characteristics to improve power and resolution for detection of diabetes susceptibility loci. RESULTS: Thirty-six of 310 (11.6%) N2 females developed type 1 diabetes between 14 and 40 weeks. Significant evidence of linkage for only a single previously reported Idd complex locus (Idd10/17/18, chromosome [Chr] 3) was indicated for clinical diabetes. The quantitative traits of insulitis either alone or combined with age at type 1 diabetes onset were significantly linked to known Idd regions on Chr 1 (Idd5 region), Chr 4 (Idd9 region), Chr 8 (Idd22), Chr 11 (Idd4.3), and proximal Chr 17 (Idd16 region). Significant 129S1/Sv resistance contributions were identified on Chr 1, 15 (two loci), and 19, with suggestive evidence for additional novel 129/Sv resistance QTL on Chr 5 and 17 and susceptibility on Chr 2. CONCLUSIONS: The 129S1/SvJ genome harbors collections of both known and potentially novel non-MHC Idd loci. Investigators targeting 129/Sv genes mapping within chromosomal regions reported herein or elsewhere in the genome need to exclude potential contributions from linked Idd loci by generating a NOD.129 control strain expressing the nontargeted allele

Site selection spectroscopy in Eu3+-doped lanthanum fluorozirconate glass and glass-ceramic

The optical properties of Eu3+-doped glass and transparent glass-ceramic with composition (in mol%) 70.2ZrF4–23.4LaF3–0.6AlF3–5.8GaF3 were investigated by site selective spectroscopy in order to study the effect of ceramization on the symmetry of Eu3 + sites. The glass-ceramic obtained after thermal treatment of the glass ZLAG contains a unique crystalline phase of unknown structure. The analysis and comparison of FLN spectra in these materials are presented and different classes of sites are discussed. We found the presence of two main site distributions for Eu3+ ions of equivalent symmetry (C2v or lower) in the glass and two sites of different symmetry (C2v or lower and C4v or lower) in tthe glass-ceramic (GC). The estimated average crystal field strength for glass and GC decreases with the 5D0 → 7F0 energy. The results suggest that the two kinds of sites identified in the glass correspond to Eu3+ ions in and out of the former network. Decay-time measurements of 5D0 level of Eu3 + evidenced energy transfer between high and low energy sites and showed an increase of lifetime from the glass to the glass-ceramic