152 research outputs found
Fibrin glue improves osteochondral scaffold fixation: study on the human cadaveric knee exposed to continuous passive motion
No full textSummaryObjectiveTo evaluate stability and integrity of bi-layer and three-layer collagen-hydroxyapatite (C-HA) osteochondral scaffolds in a human cadaveric knee exposed to continuous passive motion (CPM) with and without loading and the role of added fibrin glue to improve the press-fit fixation of C-HA scaffolds.DesignOsteochondral lesions (2.0 × 1.5 cm) were chiseled out on both condyles and trochlea in eight human cadaveric knees. A total of 24 bi-layer (5 mm, four in each condyle) or three-layer C-HA scaffolds (8 mm, eight in the trochlea, four in each condyle) were first press-fit implanted and underwent testing with CPM, 90 cycles, 0°–90°. The second set of 24 scaffolds was implanted in cleaned lesions with the addition of fibrin glue. Two knees with fibrin glue fixation were additionally exposed to 15 kg loading, with 30 cycles of CPM, 0°–30°. Then, the knees were reopened and the scaffolds were evaluated using semi-quantitative Drobnic and modified Bekkers scores.ResultsAll but two scaffolds remained in the lesions site throughout CPM. Two implants failed: both were bi-layer osteochondral scaffolds, press-fit implanted at the lateral femoral condyle (LFC). A statistically significant difference was obtained between press-fit and fibrin glue implants with both Drobnic (2.9 ± 0.7 vs 4.3 ± 0.1, P < 0.0005) and Bekkers (3.3 ± 1.0 vs 5.0 ± 0.1, P < 0.0005) scores. Additional knee loading did not affect fibrin glue scaffold fixation or integrity.ConclusionThis cadaveric study showed fibrin glue notably improved bi-layer or three-layer C-HA scaffold press-fit fixation regardless of lesion location. It is therefore recommended that fibrin glue be used during surgery to improve early post-operative C-HA scaffold stability and integrity
An Output Ripple-Free Fast Charger for Electric Vehicles Based on Grid-Tied Modular Three-Phase Interleaved Converters
No full textAn off-board dc fast battery charger for electric vehicles (EVs) with an original control strategy aimed to provide ripple-free output current in the typical EV batteries voltage range is presented in this article. The proposed configuration is based on modular three-phase interleaved converters and supplied by the low-voltage ac grid. The ac/dc interleaved three-phase active rectifier is composed of three standard two-level three-phase converter modules with a possibility to slightly adjust the dc-link voltage level in order to null the output current ripple. A modular interleaved dc/dc converter, formed by the same three-phase converter modules connected in parallel, is used as an interface between the dc link and the battery. The use of low-cost, standard and industry-recognized three-phase power modules for high-power fast EV charging stations enables the reduction of capital and maintenance costs of the charging facilities. The effect of coupling on the individual input/output inductors and total input/output current ripples has been investigated as well, considering both possible coupling implementations, i.e., inverse and direct coupling. Numerical simulations are reported to confirm the feasibility and the effectiveness of the whole EV fast charging configuration, including the proposed control strategy aimed to null the ripple of the output current. Experimental results are provided by a reduced scale prototype of the output stage to verify the ripple-free output current operation capability
Non-surgical management of early knee osteoarthritis.
No full textConservative approach is usually the first choice for the management of the knee degeneration processes, especially in the phase of the disease recognized as early osteoarthritis (OA) with no clear lesions or associated abnormalities requiring to be addressed surgically. A wide spectrum of treatments is available, from non-pharmacological modalities to dietary supplements and pharmacological therapies, as well as minimally invasive procedures involving injections of various substances aiming to restore joint homeostasis and provide clinical improvement and possibly a disease-modifying effect. Numerous pharmaceuticals have been proposed, but since no therapy has shown all the characteristic of an ideal treatment, and side effects have been reported at both systemic and local level, the use of pharmacological agents should be considered with caution by assessing the risk/benefit ratio of the drugs prescribed. Both patients and physicians should have realistic outcome goals in pharmacological treatment, which should be considered together with other conservative measures. A combination of these therapeutic options is a more preferable scenario, in particular considering the evidence available for non-pharmacological management. In fact, exercise is an effective conservative approach, even if long-term effectiveness and optimal dose and administration modalities still need to be clarified. Finally, physical therapies are emerging as viable treatment options, and novel biological approaches are under study. Further studies to increase the limited medical evidence on conservative treatments, optimizing results, application modalities, indications, and focusing on early OA will be necessary in the future. Level of evidence IV
Some further characteristics of endogenous proteinase inhibitors.
No full textLeucocytes and spleen contain four different types of protein proteinase inhibitors. Two of them can be inactivated by cathepsin D. In this work biochemical and immunological studies of the inactivation of I-2 by cathepsin D are presented. Polyacrylamide gel electrophoretic examinations indicate that cathepsin D inactivates I-2 by hydrolysis of the inhibitor molecule. The conversion of the active inhibitor into inactive protein proceeds catalytically. The studies on the inhibitor mechanism of the isoinhibitors of I-1 type explain the unusual inhibitor property of this type of inhibitor to inhibit two different types of proteinases, cysteine and serine. The evidence suggests that the inhibitory mechanism is based on an active sulfhydryl group of the inhibitor which may interact with the disulfide bridge of the inhibited proteinase
Biochemical and biological characteristics of leucocyte proteinase inhibitors.
No full textPig leucocytes contain inhibitors of neutral and thiol proteinases. These proteins could be isolated from post-granule supernatant fraction as well as from nuclear extract using ion exchange chromatography, gel chromatography and affinity chromatography. Inhibitors differ in molecular weight, isoelectric point, immunologically and their inhibition ability against tested enzymes
Work-Family Conflict across 28 European Countries: A Multi-level Approach
No full textThis volume addresses tensions between work and private life by focusing on job quality, job security, working conditions and time-use patterns of individuals and households on the one hand, and the institutional context, such as family policy institutions, and other country characteristics on the other. The length of time spent on work, job characteristics, and working conditions in general to a large extent influences the degree to which people are able to combine work and other important life domains, such as family, care and social life. Jobs which facilitate a more favourable combination of people's work and personal lives lead to a better work-life balance and higher life satisfaction, which in turn might increase identification and satisfaction with one's job and work productivity. This book explores which work-related demands and work-related resources interfere with, or facilitate, the work-life interface, and how these factors interact with the institutional settings
Factorial methods to visually explore three-way two-mode networks
No full textThree-way two mode networks are characterized by a set of n actors and a set of m events in which actors are involved, observed at r different levels (e.g., space or time occasions). They are represented by a three-dimensional relational matrix A=(aijk), where i=1, ... , n; j=1,...,m and k=1,...,r.
Usually a simultaneous analysis of ways and modes of such a matrix is not explicitly considered. Traditional approaches drop out a mode (e.g., conversion approach of two-mode networks) or a way (e.g., using of trajectories).
In this work we propose to analyze the two-mode network as it is. We show how the usual representation through the correspondence analysis does not reproduce correctly relational patterns. At the same time we propose to use Multiple Correspondence Analysis (MCA) to visually explore two-mode network. The adopted metric and the method assumptions better reproduce the structural equivalence pattern present in the two mode network. Finally, we propose the use of Multiple Factorial Analysis, that is useful to generalize MCA to three way matrix, to analyze three way two-mode networks. This method allows to visualize simultaneously the two-mode network observed in different times or spaces
BULLYING AND STRATEGIES FOR CONTRASTING THE PHENOMENON IN ITALIAN SCHOOL
No full textAfter about twenty years, Italy can be considered one of the European Nations that has more invested in terms of support for inclusion and prevention for confronting the problem of bullying in the school.
This article aims to set the problem of bullying in the framework of Italian school restructuring process. Starting from a literature review about bullying since 1970s to date, on the bases of the outcomes of some studies previously conducted, the author aims to explain because the phenomenon of bullying it is accompanied by raising the mandatory school. Through the research of eminent scholars, she argues that the crisis of values and the loss of the perspective for the future of teenagers increases the possibility of violent relationships among peers in school, where they spend much of their time.
An interpretative model on bullying is therefore highlighted using the “dramaturgic metaphor” of Goffman and focusing the role of viewer/witness (often the same classmates) for breaking of the violent triangle where perpetrator and victim are similarly victims of the same cruel play.
Finally it describes the strategies devised by the Ministry of Education which are currently applied in the schools of the Italian peninsula in a perspective of preventive and rehabilitative education both on potential protagonists ‒ victim and bully ‒ both on the viewers ‒ all those adolescents just look at the “violent drama” for fun or for weakness, without interrupting it and prevent the recurrence.
In the light of empirical evidences, it is suggested that such programs accompained from informal practices should be encouraged
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