Effect of Al substitution on structural and electrical properties of Bi1.6Pb0.4Sr2CaCu2-x Mx O8+δ superconducting ceramics

In this work we study the effect on structural and electrical properties of superconducting compound Bi1.6Pb0.4Sr 2CaCu2-y My O8+δ were M=Al (with y=0-0.6). The samples were prepared by the solid-state reaction method. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), direct current (DC) resistivity versus temperature ρ(T) and alternative current (AC) susceptibility measurements. Structural analysis shows that the crystalline lattice structure of the prepared sample belongs, mainly, to the superconductive tetragonal phase Bi(Pb)2212. The SEM micrographs show that in the undoped sample the grain size has a random distribution with few grains greater than 5 μm. The grains are very dense and well connected. A quite different microstructure is obtained for the doped samples of which grains are more connected with a flat characteristic shape of Bi(Pb)2212 superconductors. All samples exhibit a superconducting character and Tc and the superconducting volume fraction decrease with increasing rate of aluminum

Platelet-rich plasma as a potential prophylactic measure against frozen shoulder in an in vivo shoulder contracture model

INTRODUCTION: Frozen shoulder (adhesive capsulitis) is a common painful and functionally-limiting disease affecting around 2% of the population. So far, therapeutic options are limited and often unsatisfactory. Platelet-rich plasma (PRP) has been used as a treatment option in other orthopedic diseases since it contains growth factors that stimulate tissue repair. So far, the effect of PRP on frozen shoulder lacks evidence. We hypothesized that PRP may be valuable in the prophylaxis and treatment of secondary frozen shoulder due to capsular remodeling. MATERIALS AND METHODS: An experimental study of an in vivo frozen shoulder model was conducted. Twenty Sprague-Dawley rats underwent surgery in which the body of the scapula was connected to the humerus with a high-strength suture. Two groups of 8 weeks survival time were allocated; a treatment group with one intraoperative injection of PRP into the glenohumeral joint (n = 10) and a control group without PRP (n = 10). The primary outcome was the structural change in the posterior synovial membrane of the posterior and inferior part of the glenohumeral joint using a semi-quantitative grading from 0 (lowest) to 3 (highest). RESULTS: The posterior synovial membrane structural changes were significantly lower in the PRP group (median = 1 [interquartile range (IQR) = 0-1]) compared to controls (median = 2 [IQR = 1-3]) (p = 0.028). There were no differences for the remaining synovial membrane changes and fibrous capsule responses between groups. CONCLUSIONS: In this in vivo shoulder contracture model, PRP injections seem to reduce the histological severity grade of some parts (i.e., posterior synovial membrane changes) of the secondary frozen shoulder without causing any side effects. It may be considered to investigate this effect further in future studies as a potential prophylaxis of secondary frozen shoulder (e.g., in operated or immobilized shoulders) or as a treatment option for patients with frozen shoulder in the early stage

The Balanced Scorecard (BSC) as a Multidimensional Performance Measurement System Tool: Case the Company of Algeria Post

This paper aimed to clarify the role that the Balanced Scorecard (BSC) as a performance measurement tool in the company of Algeria Post. The BSC is a strategic performance management system, has been proven suitable for the public sector as the financial aspect is not their only concern. The BSC is « A multidimensional performance measurement system that should serve as decision support for managers. It includes indicators of progress and delay as well as internal and external indicators. It organizes the measures in a coherent system around four balanced perspectives: financial perspective, customer perspective, internal process, learning, and growth ». (Kaplan. S & Norton, 2004, P186)

Biomechanical Analysis of Posterior Open-Wedge Osteotomy and Glenoid Concavity Reconstruction Using an Implant-Free, J-Shaped Iliac Crest Bone Graft

BACKGROUND Posterior open-wedge osteotomy and glenoid reconstruction using a J-shaped iliac crest bone graft showed promising clinical results for the treatment of posterior instability with excessive glenoid retroversion and posteroinferior glenoid deficiency. PURPOSE To evaluate the biomechanical performance of the posterior J-shaped graft to restore glenoid retroversion and posteroinferior deficiency in a cadaveric shoulder instability model. STUDY DESIGN Controlled laboratory study. METHODS A posterior glenoid open-wedge osteotomy was performed in 6 fresh-frozen shoulders, allowing the glenoid retroversion to be set at 0°, 10°, and 20°. At each of these 3 preset angles of glenoid retroversion, the following conditions were simulated: (1) intact joint, (2) posterior Bankart lesion, (3) 20% posteroinferior glenoid deficiency, and (4) posterior J-shaped graft (at 0° of retroversion). With the humerus in the Jerk position (60° of glenohumeral anteflexion, 60° of internal rotation), stability was evaluated by measuring posterior humeral head (HH) translation (in mm) and peak translational force (in N) to translate the HH over 25% of the glenoid width. Glenohumeral contact patterns were measured using pressure-sensitive sensors. Fixation of the posterior J-graft was analyzed by recording graft micromovements during 3000 cycles of 5-mm anteroposterior HH translations. RESULTS Reconstructing the glenoid with a posterior J-graft to 0° of retroversion significantly increased stability compared with a posterior Bankart lesion and posteroinferior glenoid deficiency in all 3 preset degrees of retroversion (P < .05). There was no significant difference in joint stability comparing the posterior J-graft with an intact joint at 0° of retroversion. The posterior J-graft restored mean contact area and contact pressure comparable with that of the intact condition with 0° of retroversion (222 vs 223 mm$^{2}$, P = .980; and 0.450 vs 0.550 MPa, P = .203). The mean total graft displacement after 3000 cycles of loading was 43 ± 84 µm, and the mean maximal mediolateral graft bending was 508 ± 488 µm. CONCLUSION Biomechanical analysis of the posterior J-graft demonstrated reliable restoration of initial glenohumeral joint stability, normalization of contact patterns comparable with that of an intact shoulder joint with neutral retroversion, and secure initial graft fixation in the cadaveric model. CLINICAL RELEVANCE This study confirms that the posterior J-graft can restore stability and glenohumeral loading conditions comparable with those of an intact shoulder

Anti-angiogenic effects of pterogynidine alkaloid isolated from Alchornea glandulosa

<p>Abstract</p> <p>Background</p> <p>Angiogenesis, a complex multistep process that comprehends proliferation, migration and anastomosis of endothelial cells (EC), has a major role in the development of pathologic conditions such as inflammatory diseases, tumor growth and metastasis. Brazilian flora, the most diverse in the world, is an interesting spot to prospect for new chemical leads, being an important source of new anticancer drugs. Plant-derived alkaloids have traditionally been of interest due to their pronounced physiological activities. We investigated the anti-angiogenic potential of the naturally occurring guanidine alkaloid pterogynidine (Pt) isolated from the Brazilian plant <it>Alchornea glandulosa</it>. The purpose of this study was to examine which features of the angiogenic process could be disturbed by Pt.</p> <p>Methods</p> <p>Human umbilical vein endothelial cells (HUVEC) were incubated with 8 μM Pt and cell viability, proliferation, apoptosis, invasion and capillary-like structures formation were addressed. Nuclear factor κB (NFκB), a transcription factor implicated in these processes, was also evaluated in HUVEC incubated with Pt. Quantifications were expressed as mean ± SD of five independent experiments and one-way analysis of variance (ANOVA) followed by the Dunnet test was used.</p> <p>Results</p> <p>A significant decrease in proliferation and invasion capacity and an effective increase in apoptosis as assessed by bromodeoxyuridine (BrdU), double-chamber and terminal transferase dUTP nick end labeling (TUNEL) assay, respectively, have been found. Pt also led to a drastic reduction in the number of capillary-like structures formation when HUVEC were cultured on growth factor reduced-Matrigel (GFR-Matrigel) coated plates. In addition, incubation of HUVEC with Pt resulted in reduced NFκB activity.</p> <p>Conclusion</p> <p>These findings emphasize the potential use of Pt against pathological situations where angiogenesis is stimulated as tumor development.</p

Morphological, structural and ellipsometric investigations of Cr doped TiO2 thin films prepared by sol-gel and spin coating

International audiencePure and chromium doped titanium dioxide (TiO2) thin films at different atomic percentages (0.5%, 1.3% and 2.9%) have been elaborated on ITO/Glass substrates by sol-gel and spin-coating methods using titanium (IV) isopropoxide as a precursor. The surface morphology of films was investigated by scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM), the structure was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission microscopy (HRTEM). SEM and HRTEM show homogenous and polycrystalline films. XRD patterns indicate a phase transition from anatase to anatase-rutile leading to expand the absorption band of TiO2 molecules around 520 cm(-1) in FTIR spectra. The optical constants such as the refractive index (n), the extinction coefficient (K) and the band gap (E-g) as well as the film thickness are determined using spectroscopic ellipsometry technique and Fourouhi-Blommer dispersion model. Results show three major changes; (i) the thickness of pure TiO2 layer is 54 nm, which linearly decreases when the layer is doped with chromium and reaches 33 nm for a doping concentration of 2.9%, (ii) the band gap energy (E-g) is also linearly reduced from 3.24 eV to 2.80 eV when the Cr-doping agent increases, and, (iii) a phase transition from anatase to anatase-rutile is observed causing an increase in values of n(lambda) for wavelength greater than 350 nm. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Results after delayed axillary nerve reconstruction with interposition of sural nerve grafts

HYPOTHESIS: Satisfactory results after repair of isolated axillary nerve lesions using sural nerve autografts have been reported, but a delay between injury and surgical repair exceeding 6 months was one of the most important negative predictors of functional outcome. From our experience, we hypothesize that good results can be obtained even after a delay exceeding 6 months and we opted in this study to assess the value of delayed axillary nerve reconstruction. MATERIALS AND METHODS: We evaluated clinical outcome and donor-site morbidity in 12 patients (mean age, 37; range, 19-66 years) who underwent axillary nerve repair with sural nerve graft with an average 11.25-month a delay between trauma and surgery (range, 8-20 months). Follow-up examination at least 24 months after treatment included assessment of shoulder range of motion, deltoid muscle strength in near full extension, deltoid extension lag, and sensibility. Constant Score, subjective shoulder value, and the Disabilities of Arm, Shoulder and Hand score were also assessed. RESULTS: All patients showed an improved deltoid function of at least M3. Postoperative extension lag, as the most specific sign of isolated deltoid function, improved from 57.5 degrees to 14.2 degrees. All stated that they would have identical elective surgery again. Relevant donor-site morbidity was not observed. CONCLUSION: Our data indicate that even delayed axillary nerve grafting may lead to satisfactory functional results with a low morbidity and should therefore be done in selected patients. 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved

Local activation of light-induced degradation in co-doped boron-phosphorus silicon: Evidence of defect diffusion phenomena

International audienceThis study is interested in the local activation of Light-induced degradation (LID) defect in highly co-doped silicon wafers with boron and phosphorus. For this purpose, the experiments are focused on measuring the minority carrier lifetime before and after LID activation via a mapping technique. The LID defect density exhibits a Gaussian distribution centered on the excitation point of the laser beam; the intensity of the Gaussian distribution of the LID defect varies with the concentration of the co-dopants. The lifetime of the minority carriers decreases in all-silicon sample regions, while the excitation laser beam focuses on an area of approximately one mm2. This observation indicates that LID defects are activated even in the unexcited areas of silicon wafers, suggesting a LID diffusion phenomenon from the laser excitation point to the whole silicon wafer. We deduce that a high phosphorus doping level in silicon wafers leads to a significant reduction in the LID effect

Reconstruction of the medial patellofemoral ligament using the adductor magnus tendon: an anatomic study

PURPOSE: The aims of this study were to evaluate the anatomic feasibility of medial patellofemoral ligament (MPFL) reconstruction using a part of the adductor magnus tendon and to identify possible risks. METHODS: Twenty cadaveric knees were dissected. The distal part of the adductor magnus tendon was evaluated with respect to the anatomic topography and its utility for MPFL reconstruction. To estimate the risk of injuring the neurovascular structures, the distance from the adductor tubercle to the adductor hiatus was evaluated. An MPFL reconstruction was carried out by preserving the distal insertion on the adductor tubercle and redirecting the proximal portion of the tendon to the medial aspect of the patella. RESULTS: The anatomic investigation showed the following relationships: The mean distance from the adductor tubercle to the adductor hiatus was 99 ± 14 mm (range, 80 to 120 mm). A graft length of 52 ± 5 mm (range, 45 to 63 mm) with the addition of 10 to 20 mm for fixation was found to be necessary for MPFL reconstruction. The difference between the desired graft length and the distance to the adductor hiatus was found to be at least 30 mm in all cases (mean, 46 mm). Leaving the graft attached to the adductor tubercle resulted in a nearly anatomic femoral attachment of the reconstructed MPFL. Complete detachment of the distal adductor magnus attachment was consistently avoidable. CONCLUSIONS: The adductor magnus tendon was found to be a useful graft for MPFL reconstruction. However, anatomic dangers (damage to the neurovascular bundle of the adductor hiatus, the saphenous nerve, or the saphenous branch of the descending genicular artery) during graft harvest must be considered. CLINICAL RELEVANCE: Anatomic knowledge is essential during adductor magnus tendon harvest to avoid damage to neurovascular structures. The adductor magnus tendon is an interesting alternative graft option for MPFL reconstruction if anatomic dangers are considered and avoided