Comparison of hot-electron transmission in ferromagnetic Ni on epitaxial and polycrystalline Schottky interfaces

The hot-electron attenuation length in Ni is measured as a function of energy across two different Schottky interfaces viz. a polycrystalline Si(111)/Au and an epitaxial Si(111)/NiSi_2 interface using ballistic electron emission microscopy (BEEM). For similarly prepared Si(111) substrates and identical Ni thickness, the BEEM transmission is found to be lower for the polycrystalline interface than for the epitaxial interface. However, in both cases, the hot-electron attenuation length in Ni is found to be the same. This is elucidated by the temperature-independent inelastic scattering, transmission probabilities across the Schottky interface, and scattering at dissimilar interfaces.Comment: 5 pages, 5 figure

Finite Element Modeling Application in Forensic Practice: A Periprosthetic Femoral Fracture Case Study

The incidence of periprosthetic fractures has rapidly increased in the last two decades and has been the cause of a large number of revision surgeries and permanent physical disability for many patients, as well as a significant socioeconomic burden for many nations. This research deals with a periprosthetic femur fracture real event, occurred following a total hip arthroplasty and treated with one of the most widespread internal fixation methods: the implant of a periprosthetic femur plate system. A Finite Element analysis was performed to investigate the implanted femur plate break after a short follow-up and to understand the plate break causes. Such events are currently object of forensic debate as more and more often hospitals, surgeons, and medical device manufacturers are denounced by patients to whom similar events occur. In this work, different load situations acting on the femur during daily and incidental activities were simulated, in order to validate the correct behavior of the plate, according to the intended use recommended by the manufacturer. The analysis demonstrates that the plate failure can occur in situations of unconventional loading such as that caused by stumbling and in presence of incomplete bone healing

Biomechanical role and motion contribution of ligaments and bony constraints in the elbow stability: A preliminary study

In flexion-extension motion, the interaction of several ligaments and bones characterizes the elbow joint stability. The aim of this preliminary study was to quantify the relative motion of ulna respect to humerus in two human elbow specimens and to investigate the constraints role for maintaining the joint stability in different dissections condition. Two clusters of 4 markers were fixed respectively to ulna and humerus, and their trajectory was recorded by a motion capture system during orthopedic maneuver. Considering the medial ulnar collateral posterior bundle (pMUCL) and the coronoid, two dissection sequences were executed. The orthopedic maneuver of compression, pronation and varus force was repeated at 30°, 60°, 90° flexion for the functional investigation of constraints. Ulna deflection was compared to a baseline flexion condition. Respect to intact elbow, the coronoid osteotomy influences the elbow stability at 90° (deflection=11.49±17.39 mm), while small differences occur at 30° and 60°, due to ligaments constraint. The contemporary pMUCL dissection and coronoid osteotomy causes elbow instability, with large deflection at 30° (deflection=34.40±9.10 mm), 60° (deflection=45.41±18.47 mm) and 90° (deflection=52.16±21.92 mm). Surgeons may consider the pMUCL reconstruction in case of unfixable coronoid fracture

Are suprapectineal quadrilateral surface buttressing plates performances superior to traditional fixation? A finite element analysis

Acetabular fractures have a high impact on patient’s quality of life, and because acetabular fractures are high energy injuries, they often co-occur with other pathologies such as damage to cartilage that could increase related morbidity; thus, it appears of primary importance developing reliable treatments for this disease. This work aims at the evaluation of the biomechanical performances of non-conservative treatments of acetabular fractures through a finite element approach. Two pelvic plates models (the standard suprapectineal plate—SPP, and a suprapectineal quadrilateral surface buttressing plate—SQBP) were analyzed when implanted on transverse or T-shaped fractures. The plates geometries were adapted to the specific hemipelvis, mimicking the bending action that the surgeon performs on the plate intraoperatively. Implemented models were tested in a single leg stance condition. The obtained results show that using the SQBP plate in transverse and T-shaped acetabular fractures generates lower bone stress if compared to the SPP plate. Interfragmentary movement analysis shows that the SQBP plate guarantees greater stability in transverse fractures. In conclusion, the SQBP plate seems worthy of further clinical analysis, having resulted as a promising option in the treatment of transverse and T-shaped acetabular fractures, able to reduce bone stress values and to get performances comparable, and in some cases superior, to traditional fixation

Testing the specificity of environmental risk factors for developmental outcomes.

Developmental theories often assume that specific environmental risks affect specific outcomes. Canonical Correlation Analysis was used to test whether 28 developmental outcomes (measured at 11-15 years) share the same early environmental risk factors (measured at 0-3 years), or whether specific outcomes are associated with specific risks. We used data from the UK Millennium Cohort Study (N = 10,376, 51% Female, 84% White) collected between 2001 and 2016. A single environment component was mostly sufficient for explaining cognition and parent-rated behavior outcomes. In contrast, adolescents' alcohol and tobacco use were specifically associated with their parents', and child-rated mental health was weakly associated with all risks. These findings suggest that with some exceptions, many different developmental outcomes share the same early environmental risk factors

Effectiveness of high dose sublingual immunotherapy to induce a stepdown of seasonal asthma: a pilot study

There is ample evidence to support the efficacy of sublingual immunotherapy (SLIT) on allergic rhinitis, while there is less solid data regarding asthma. We evaluated the effects of a high dose birch SLIT on birch-induced rhinitis and asthma in a controlled study

Pelvic ring fractures: External fixation comparative numerical structural analysis

External fixation (EF) is commonly practiced for pelvic ring fractures management. Many parameters influence mechanical performances of external fixators. Our virtual 3D model of the pelvic ring introduces the advantage of differentiating the mechanical properties of cortical and cancellous bone along with the complex boundary conditions of major ligaments. We assessed stiffness variations by increasing fixator pins depth and we evaluated dislocation related to load intensity and sitting angle

Spin Structure of K Valleys in Single-Layer WS2 on Au(111)

The spin structure of the valence and conduction bands at the K\u304 and K\u304\u2032 valleys of single-layer WS2 on Au(111) is determined by spin- and angle-resolved photoemission and inverse photoemission. The bands confining the direct band gap of 1.98 eV are out-of-plane spin polarized with spin-dependent energy splittings of 417 meV in the valence band and 16 meV in the conduction band. The sequence of the spin-split bands is the same in the valence and in the conduction bands and opposite at the K\u304 and the K\u304\u2032 high-symmetry points. The first observation explains "dark" excitons discussed in optical experiments; the latter points to coupled spin and valley physics in electron transport. The experimentally observed band dispersions are discussed along with band structure calculations for a freestanding single layer and for a single layer on Au(111)

Direct and indirect links between children’s socio-economic status and education: pathways via mental health, attitude, and cognition

AbstractA child’s socio-economic environment can profoundly affect their development. While existing literature focusses on simplified metrics and pair-wise relations between few variables, we aimed to capture complex interrelationships between several relevant domains using a broad assessment of 519 children aged 7–9 years. Our analyses comprised three multivariate techniques that complimented each other, and worked at different levels of granularity. First, an exploratory factor analysis (principal component analysis followed by varimax rotation) revealed that our sample varied along continuous dimensions of cognition, attitude and mental health (from parallel analysis); with potentially emerging dimensions speed and socio-economic status (passed Kaiser’s criterion). Second, k-means cluster analysis showed that children did not group into discrete phenotypes. Third, a network analysis on the basis of bootstrapped partial correlations (confirmed by both cross-validated LASSO and multiple comparisons correction of binarised connection probabilities) uncovered how our developmental measures interconnected: educational outcomes (reading and maths fluency) were directly related to cognition (short-term memory, number sense, processing speed, inhibition). By contrast, mental health (anxiety and depression symptoms) and attitudes (conscientiousness, grit, growth mindset) showed indirect relationships with educational outcomes via cognition. Finally, socio-economic factors (neighbourhood deprivation, family affluence) related directly to educational outcomes, cognition, mental health, and even grit. In sum, cognition is a central cog through which mental health and attitude relate to educational outcomes. However, through direct relations with all components of developmental outcomes, socio-economic status acts as a great ‘unequaliser’.</jats:p