223 research outputs found
Gender diversity in corporate governance and its effect on financial performance: a study on FTSE-MIB listed companies
I examine the presence of women in Italian corporate boards after the inception of the Act 120/2011 by the Italian Government. I considered all the directors of the 40 companies listed in the FTSE – MIB index in 2015 and analyze the implications of gender diversity in corporate boards. Furthermore I study the correlation between gender diversity and financial performance. Different conclusions can be extrapolated from my analysis. My study shows a statistical significance between the presence of female directors in a company and its Return on Asset (ROA) in two different periods. The analysis led to the existence of a statistical significance between ROE and the percentage of female directors in administration boards. Finally I did not find any significant relation between Profit Margin and a diverse board
Facteurs biomécaniques de risques de la cyphose jonctionnelle proximale
RÉSUMÉ
Les déformations rachidiennes telles que la scoliose sont des pathologies du système
musculo-squelettique qui nécessitent un traitement chirurgical d’instrumentation dans les cas de
courbures pathologiques sévères (angle de Cobb > 40° pour les cas de scoliose) (Weinstein 2001;
Morcuende and Weinstein 2003). Cette intervention d’instrumentation consiste à fixer des
implants sur les vertèbres et redresser le rachis à l’aide de tiges métalliques, ce qui mène à la
fusion permanente du rachis. Bien que ce traitement permette une correction efficace des
courbures pathologiques du rachis (Weinstein 2001), la survenue de complications
postopératoires peut parfois entraîner une révision de l’instrumentation. La première cause de
révision est la cyphose jonctionnelle proximale (CJP) (Schairer, Carrer et al. 2013), avec une
prévalence entre 20% et 43% (Yang and Chen 2003; Yagi, King et al. 2012). La CJP se manifeste
comme une hypercyphose des vertèbres adjacentes au-dessus de l'instrumentation. Plusieurs
études rétrospectives ont été réalisées afin d’en identifier les causes. Les facteurs de risque
associés à la survenue et à la progression de la CJP incluent la dissection proximale des tissus
mous postérieurs, la dégénérescence de la capsule articulaire, l’équilibre sagittal pré- et
postopératoire, la thoracoplastie, la qualité osseuse, l'obésité et la raideur de l’instrumentation
(Glattes, Bridwell et al. 2005; Kim, Bridwell et al. 2005; DeWald and Stanley 2006; Kim, Lenke
et al. 2007; Yagi, King et al. 2012). Ainsi, on rapporte que la CJP pourrait être associée au
nombre de vertèbres instrumentées, au type d’implant proximal ou de manière plus générale à la
configuration de l'instrumentation au niveau de la vertèbre proximale instrumentée. Les
pathomécanismes de la CJP demeurent toutefois encore controversés. En effet, les conclusions
rapportées dans la littérature sont parfois contradictoires et n’arrivent pas à isoler l’effet
spécifique d’une variable donnée par rapport à la CJP. En outre, aucune étude biomécanique n’a
rapporté l'impact biomécanique de différentes variables de la chirurgie rachidienne sur les indices
géométrico-mécaniques reliés à la CJP.
L’objectif de ce projet de maîtrise a donc été de développer un modèle biomécanique de la
chirurgie d’instrumentation afin d’analyser et comprendre les pathomécanismes postopératoires
du segment jonctionnel proximal du rachis. Six variables chirurgicales pouvant augmenter
potentiellement le risque de survenue de la CJP ont ainsi été analysées.----------ABSTRACT
Spinal deformities such as scoliosis are a group of musculoskeletal disorders requiring surgical
instrumentation in cases of severe pathological curvatures (e.g. Cobb angle > 40° for scoliosis)
(Weinstein 2001; Morcuende and Weinstein 2003). Spinal instrumentation is a surgical procedure
that stabilizes the spine and fuses vertebrae with implanted devices, such as metallic rods, screws
and hooks. Although this treatment allows effective correction of pathological spinal curvatures
(Weinstein 2001), the occurrence of postoperative complications can sometimes lead to a revision
of the instrumentation. The first cause of revision surgery is the proximal junctional kyphosis
(PJK) (Schairer, Carrer et al. 2013), having a prevalence between 20% and 43% (Yang and Chen
2003; Yagi, King et al. 2012). PJK appears as a hyperkyphosis of non instrumented proximal
vertebrae. Several retrospective studies have been conducted to identify its causes. Risk factors
related to PJK occurrence and progression include the proximal dissection of the posterior soft
tissues, the joint capsule degeneration, the pre- and postoperative sagittal balance, the
thoracoplasty, the bone quality, the obesity and the stiffness of the instrumentation (Glattes,
Bridwell et al. 2005; Kim, Bridwell et al. 2005; DeWald and Stanley 2006; Kim, Lenke et al.
2007; Yagi, King et al. 2012). It is also reported that PJK could be associated to the number of
instrumented vertebrae, the type of proximal implant or the construct configuration at upper
instrumented vertebra. However, pathomechanisms of PJK are still controversial because
findings reported in the literature are sometimes contradictory and not able to isolate the effect of
a specific variable on PJK. In addition, no computational study has reported the impact of several
surgical variables on biomechanical indices related to PJK.
The objective of this Master project was therefore to develop a biomechanical model of spinal
instrumentation in order to analyze and better understand the postoperative pathomechanisms of
proximal junctional spinal segment. Six surgical variables potentially increasing the risk for PJK
occurrence have been analyzed.
In order to achieve this objective, a multibody model was developed and validated to
computationally simulate surgical instrumentations of six adult patients affected by PJK. For
each case, the spinal tridimensional geometry was reconstructed using two calibrated
preoperative radiographs (postero-anterior and lateral). In these models, each vertebra wa
Photo-induced pyridine substitution in cis-[Ru(bpy)(2)(py)(2)]Cl-2 : a snapshot by time-resolved X-ray solution scattering
Determination of transient structures in light-induced processes is a challenging goal for time-resolved techniques. Such techniques are becoming successful in detecting ultrafast structural changes in molecules and do not require the presence of probe-like groups. Here, we demonstrate that TR-WAXS (Time-Resolved Wide Angle X-ray Scattering) can be successfully employed to study the photochemistry of cis-[Ru(bpy)(2)(py)(2)]Cl-2, a mononuclear ruthenium complex of interest in the field of photoactivatable anticancer agents. TR-WAXS is able to detect the release of a pyridine ligand and the coordination of a solvent molecule on a faster timescale than 800 ns of laser excitation. The direct measurement of the photodissociation of pyridine is a major advance in the field of time-resolved techniques allowing detection, for the first time, of the release of a multiatomic ligand formed by low Z atoms. These data demonstrate that TR-WAXS is a powerful technique for studying rapid ligand substitution processes involving photoactive metal complexes of biological interest
Protein differences among the Mediterranean species of the genus Spicara.
Protein electrophoresis (PAGE) was used to study the three morphologically different species of
Spicara (S. flexuosa, S. maena, S. smaris). Of the 28 enzymatic and additional myogenic loci,
five monomorphic loci (LDH-1*, G6PD-1*, PGI-1* and two PMMs*) were species-specific
markers of S. smaris with respect to S. flexuosa and S. maena. Four of the 28 enzymatic loci
were polymorphic (EST-1*, GLDH*, PEPD*, PGI-2*). Discriminating genetic markers were
not identified between S. flexuosa and S. maena. Genetic distance (D) as calculated by Nei’s
index (1978), between S. smaris v. S. maena and S. flexuosa showed a value, respectively of
D=0·137 and 0·141. Between S. flexuosa and S. maena the value was D=0·006. From the data
it can be inferred that S. flexuosa and S. maena are conspecific, despite morphological
differences
Tilting refractive x-ray lenses for fine-tuning their focal length
In this work, we measure and model tilted x-ray refractive lenses to
investigate their effects on an x-ray beam. The modelling is benchmarked
against at-wavelength metrology obtained with x-ray speckle vector tracking
experiments (XSVT) at the BM05 beamline at the ESRF-EBS light source, showing
very good agreement. This validation permits us to explore possible
applications of tilted x-ray lenses in optical design: we demonstrate that
tilting 1D lenses around their focusing direction can be used for fine-tuning
their focal length with possible applications in beamline optical design.Comment: 15 pages, 13 figures, 38 references to be submitted to Optics Expres
Structural dynamics probed by X-ray pulses from synchrotrons and XFELs
This review focuses on how short X-ray pulses from synchrotrons and XFELs can be used to track light-induced structural changes in molecular complexes and proteins via the pump–probe method. The upgrade of the European Synchrotron Radiation Facility to a diffraction-limited storage ring, based on the seven-bend achromat lattice, and how it might boost future pump–probe experiments are described. We discuss some of the first X-ray experiments to achieve 100 ps time resolution, including the dissociation and in-cage recombination of diatomic molecules, as probed by wide-angle X-ray scattering, and the 3D filming of ligand transport in myoglobin, as probed by Laue diffraction. Finally, the use of femtosecond XFEL pulses to investigate primary chemical reactions, bond breakage and bond formation, isomerisation and electron transfer are discussed
Revitalizing an important field in biophysics: The new frontiers of molecular crowding
Taking into account the presence of the crowded environment of a macromolecule has been an important goal of biology over the past 20 years. Molecular crowding affects the motions, stability and the kinetic behaviour of proteins. New powerful approaches have recently been developed to study molecular crowding, some of which make use of the synchrotron radiation light. The meeting “New Frontiers in Molecular Crowding” was organized in July 2022at the European Synchrotron Radiation facility of Grenoble to discuss the new frontiers of molecular crowding. The workshop brought together researchers from different disciplines to highlight the new developments of the field, including areas where new techniques allow the scientists to gain unprecedently expected information. A key conclusion of the meeting was the need to build an international and interdisciplinary research community through enhanced communication, resource-sharing, and educational initiatives that could let the molecular crowding field flourish further
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