Determination of the deformation potentials of GaAs0.80P0.20

3 páginas, 2 figuras, 2 tablas.Deformation potentials can be determined by measuring the variation of the energy of the electronic transitions with strain. In this work, the hydrostatic and shear potentials of the band‐gap electronic transition (E0) and the transitions along the 〈111〉 direction (E1) of GaAs1−xPx, x≊0.20, have been determined by electroreflectance characterization of GaAs1−xPx layers with different levels of strain.Project 6854 “BLES” (Buffer Layer Engineering in Semiconductors) and the Spanish CICYT under Project No. MAT92-0262 for their support.Peer reviewe

Symptomatic seizures in preterm newborns: a review on clinical features and prognosis

Neonatal seizures are the most common neurological event in newborns, showing higher prevalence in preterm than in full-term infants. In the majority of cases they represent acute symptomatic phenomena, the main etiologies being intraventricular haemorrhage, hypoxic-ischemic encephalopathy, central nervous system infections and transient metabolic derangements.Current definition of neonatal seizures requires detection of paroxysmal EEG-changes, and in preterm newborns the incidence of electrographic-only seizures seems to be particularly high, further stressing the crucial role of electroencephalogram monitoring in this population. Imaging work-up includes an integration of serial cranial ultrasound and brain magnetic resonance at term-equivalent age. Unfavourable outcomes following seizures in preterm infants include death, neurodevelopmental impairment, epilepsy, cerebral palsy, hearing and visual impairment. As experimental evidence suggests a detrimental role of seizures per se in determining subsequent outcome, they should be promptly treated with the aim to reduce seizure burden and long-term disabilities. However, neonatal seizures show low response to conventional anticonvulsant drugs, and this is even more evident in preterm newborns, due to intrinsic developmental factors. As a consequence, as literature does not provide any specific guidelines, due to the lack of robust evidence, off-label medications are often administered in clinical practice

Design Dynamics. Navigating the new Complex Landscape of Omnichannel Fashion Retail

The fashion industry is entering the dynamic global competitive market, promoting various actions prioritising design, creativity, sustainability, and technological advancement as pivotal factors. At the same time, it is reimagining its business models to adapt to the changing landscape. The rise of pervasive connectivity, intuitive interfaces and innovative interaction channels has triggered a revolution in fashion retail, reshaping customer behaviour and expectations. The traditional retail framework has evolved into a fully interconnected omnichannel system. This transformation is characterised by the proliferation of physical and virtual channels and touch points and by the adoption of a more flexible and integrated approach. In this dynamic context, design plays a central role, possessing the ability to impart meaning to the production and distribution system. Design-led innovation represents an incremental form of innovation that injects a nuanced range of meaning into the marketplace, extending beyond tangible objects, including discourses, expressions, narratives, visual images, symbols, metaphors, and spaces. The book analyses the multifaceted nature of the fashion retail experience through the lens of the design discipline, aiming to contextualise the evolution of retail within increasingly complex processes, networks and interconnections, both theoretically and practically. The focus is on retail design, delving into the new skills required and the valuable tools needed to apply them in inherently multidisciplinary contexts. Ultimately, the aim is to navigate the intricate terrain of retail evolution and shed light on the evolving role of design in this multifaceted sector

A fracture mechanics model to study indentation cutting

Many cutting processes, such as chopping, slicing, and carving, consist in 2 different stages: an initial stage of indentation, in which the cutting tool is pushed into the material under the action of an external force, and a second stage, where the target material undergoes a progressive separation. This second stage is characterised by the formation of a fracture surface followed by the cut propagation due to the increasing external force, until eventually a steady state might occur. The purpose of this paper is to analyse the cutting process by means of some concepts of fracture mechanics and discuss the occurrence of the steady state. A simple model is used to obtain an analytic expression of the stress intensity factor at the tip of the cut and investigate the evolution of the fracture process. It is found that the cut propagation depends on the wedge sharpness. The analytic results are compared with finite element analyses, where the effect of tip blunting due to plasticity is taken into account. The influence of the cutting tool geometry is also discussed

A full menu for stem-cell research

A report on the Stem Cell EuroConference, Paris, France, 9-10 December 2004

full model multiaxial fatigue life calculations with different criteria

Abstract Fatigue design of structural components under multiaxial loading often relies on fatigue life calculations based on a post-processing of the full-field elastic stress/strain maps obtained from finite element (FE) analysis. In the present article, a post-processing tool is adopted to compute the fatigue life of a structural component, and multiaxial fatigue assessment is carried out by considering different criteria such as that of Smith-Watson-Topper and of Fatemi-Socie. The present paper focuses on a specific structural component related to a quarter-turn heavy-duty valve actuator, called scotch yoke, commonly used in many application sectors such as oil & gas, power and chemical industries. The fatigue assessment of the component is carried out by employing a full-model FE analysis, considering fillet-welded joints exposed to in-phase constant amplitude cyclic bending-torsion fatigue load with load ratio R=-1, with applied maximum load according to EN 15714-3, which is the standard in the valve actuator sector. The elastic stress/strain field extracted from the FE model is used to perform the fatigue assessment of the fillet-welded joints, where the potential fatigue crack initiation points (weld toe and weld root) are described by adopting an effective radius at the weld notches

on the fracture processes of cutting

Abstract: The process of cutting is treated as a fracture mechanical process. For an elliptic rigid wedge pressed into an elastic material, fracture may occur as an autonomous process if the tip of the wedge is sufficiently blunt or is affected by the geometry of the wedge if the tip is sharp. The conditions leading to the former or the latter case is obtained as a relation between the wedge tip radius, the fracture toughness and the modulus of elasticity. These limits and the intermediate states are discussed. The implications of the drastic changes of the mechanical state of the near tip region when the wedge edge is sharp are also discussed

Older persons' perceptions of general practitioner or specialist primary care physicians : same point of view?

BACKGROUND: Identification of a Primary Care Physician (PCP) by older patients is considered as essential for the coordination of care, but the extent to which identified PCPs are general practitioners or specialists is unknown. This study described older patients' experiences with their PCP and tested the hypothesis of differences between patients who identify a specialist as their PCP (SP PCP) and those who turn to a general practitioner (GP PCP). METHODS: In 2012, a cross-sectional postal survey on care was conducted in the 68+ year old population of the canton of Vaud. Data was provided by 2,276 participants in the ongoing Lausanne cohort 65+ (Lc65+), a study of those born between 1934 and 1943, and by 998 persons from an additional sample drawn to include the population outside of Lausanne or born before 1934. RESULTS: Participants expressed favourable perceptions, at rates exceeding 75% for most items. However, only 38% to 51% responded positively for out-of-hours availability, easy access and at home visits, likelihood of prescribing expensive medication if needed, and doctors' awareness of over-the-counter drugs. 12.0% had an SP PCP, in 95.9% specialised in a discipline implying training in internal medicine. Bivariate and multivariate analyses did not result in significant differences between GP and SP PCPs regarding perceptions of accessibility/availability, doctor-patient relationship, information and continuity of care, prevention, spontaneous use of the emergency department or ambulatory care utilisation. CONCLUSIONS: Experiences of old patients were mostly positive despite some lack in reported hearing, memory testing, and colorectal cancer screening. We found no differences between GP and SP PCP groups

A salvage surgical solution for recurrent lymphangioma of the prepuce

Treatment of lymphangioma, circumscriptum of the prepuce is often technically demanding. Many different medical and surgical approaches have been described over the years, none of which has proved completely successful. We describe a case in which skin deficiency was a problem after prior multiple excisions of lymphangiomatous tissue. We decided to bury the degloved shaft in the scrotum. After 6 months the penis was raised and reconstructed using scrotal skin; this achieved satisfactory skin coverage. In such cases piliferous follicles can easily be dealt with at a later stage by cosmetic treatment.We believe this technical, approach may be a valid alternative to conventional procedures (i.e. grafts and flaps) especially when extensive resection makes skin coverage particularly difficult. (C) 2004 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved