150 research outputs found
Anti-AGEs Algerian vegetal extracts. Phytochemical study of Daucus aureus desf. (Apiaceae)
International audienc
Shear band dynamics from a mesoscopic modeling of plasticity
The ubiquitous appearance of regions of localized deformation (shear bands)
in different kinds of disordered materials under shear is studied in the
context of a mesoscopic model of plasticity. The model may or may not include
relaxational (aging) effects. In the absence of relaxational effects the model
displays a monotonously increasing dependence of stress on strain-rate, and
stationary shear bands do not occur. However, in start up experiments transient
(although long lived) shear bands occur, that widen without bound in time. I
investigate this transient effect in detail, reproducing and explaining a t^1/2
law for the thickness increase of the shear band that has been obtained in
atomistic numerical simulations. Relaxation produces a negative sloped region
in the stress vs. strain-rate curve that stabilizes the formation of shear
bands of a well defined width, which is a function of strain-rate. Simulations
at very low strain-rates reveal a non-trivial stick-slip dynamics of very thin
shear bands that has relevance in the study of seismic phenomena. In addition,
other non-stationary processes, such as stop-and-go, or strain-rate inversion
situations display a phenomenology that matches very well the results of recent
experimental studies.Comment: 10 pages, 10 figure
LEÓN, JOSÉ CLAUDIO DE Y SRA. [Material gráfico]
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201
Nurse-led care for the management of rheumatoid arthritis: a review of the global literature and proposed strategies for implementation in Africa and the Middle East
Globally, increasing demand for rheumatology services has led to a greater reliance on non-physician healthcare professionals (HCPs), such as rheumatology nurse specialists, to deliver care as part of a multidisciplinary team. Across Africa and the Middle East (AfME), there remains a shortage of rheumatology HCPs, including rheumatology nurses, which presents a major challenge to the delivery of rheumatology services, and subsequently the treatment and management of conditions such as rheumatoid arthritis (RA). To further explore the importance of nurse-led care (NLC) for patients with RA and create a set of proposed strategies for the implementation of NLC in the AfME region, we used a modified Delphi technique. A review of the global literature was conducted using the PubMed search engine, with the most relevant publications selected. The findings were summarized and presented to the author group, which was composed of representatives from different countries and HCP disciplines. The authors also drew on their knowledge of the wider literature to provide context. Overall, results suggest that NLC is associated with improved patient perceptions of RA care, and equivalent or superior clinical and cost outcomes versus physician-led care in RA disease management. Expert commentary provided by the authors gives insights into the challenges of implementing nurse-led RA care. We further report practical proposed strategies for the development and implementation of NLC for patients with RA, specifically in the AfME region. These proposed strategies aim to act as a foundation for the introduction and development of NLC programs across the AfME region. © 2020, The Author(s)
Phenomenology and physical origin of shear-localization and shear-banding in complex fluids
We review and compare the phenomenological aspects and physical origin of
shear-localization and shear-banding in various material types, namely
emulsions, suspensions, colloids, granular materials and micellar systems. It
appears that shear-banding, which must be distinguished from the simple effect
of coexisting static-flowing regions in yield stress fluids, occurs in the form
of a progressive evolution of the local viscosity towards two significantly
different values in two adjoining regions of the fluids in which the stress
takes slightly different values. This suggests that from a global point of view
shear-banding in these systems has a common physical origin: two physical
phenomena (for example, in colloids, destructuration due to flow and
restructuration due to aging) are in competition and, depending on the flow
conditions, one of them becomes dominant and makes the system evolve in a
specific direction.Comment: The original publication is available at http://www.springerlink.co
GaSbBi alloys and heterostructures: fabrication and properties
International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures
Recent experimental probes of shear banding
Recent experimental techniques used to investigate shear banding are
reviewed. After recalling the rheological signature of shear-banded flows, we
summarize the various tools for measuring locally the microstructure and the
velocity field under shear. Local velocity measurements using dynamic light
scattering and ultrasound are emphasized. A few results are extracted from
current works to illustrate open questions and directions for future research.Comment: Review paper, 23 pages, 11 figures, 204 reference
Epidemiology of surgery associated acute kidney injury (EPIS-AKI) : a prospective international observational multi-center clinical study
The incidence, patient features, risk factors and outcomes of surgery-associated postoperative acute kidney injury (PO-AKI) across different countries and health care systems is unclear. We conducted an international prospective, observational, multi-center study in 30 countries in patients undergoing major surgery (> 2-h duration and postoperative intensive care unit (ICU) or high dependency unit admission). The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay. We studied 10,568 patients and 1945 (18.4%) developed PO-AKI (1236 (63.5%) KDIGO stage 1500 (25.7%) KDIGO stage 2209 (10.7%) KDIGO stage 3). In 33.8% PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU. Patients with PO-AKI had greater ICU (6.3% vs. 0.7%) and hospital (8.6% vs. 1.4%) mortality, and longer ICU (median 2 (Q1-Q3, 1-3) days vs. 3 (Q1-Q3, 1-6) days) and hospital length of stay (median 14 (Q1-Q3, 9-24) days vs. 10 (Q1-Q3, 7-17) days). Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration. In a comprehensive multinational study, approximately one in five patients develop PO-AKI after major surgery. Increasing severity of PO-AKI is associated with a progressive increase in adverse outcomes. Our findings indicate that PO-AKI represents a significant burden for health care worldwide
EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial
More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369
From airfield to airport: an institutionalist-historical approach to the early development of Amsterdam Airport Schiphol, 1916-1940
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