270 research outputs found
Black holes in extended gravity theories in Palatini formalism
We consider several physical scenarios where black holes within classical
gravity theories including and Ricci-squared corrections and formulated
\`a la Palatini can be analytically studied.Comment: 4 pages, contribution to the "Spanish Relativity Meeting in Portugal
2012 (Progress in Mathematical Relativity, Gravitation and Cosmology)",
Springer Proceedings in Mathematics (to appear
Design of a case management model for people with chronic disease (Heart Failure and COPD). Phase I: modeling and identification of the main components of the intervention through their actors: patients and professionals (DELTA-ICE-PRO Study
Background
Chronic diseases account for nearly 60% of deaths around the world. The extent of this silent epidemic has not met determined responses in governments, policies or professionals in order to transform old Health Care Systems, configured for acute diseases. There is a large list of research about alternative models for people with chronic conditions, many of them with an advanced practice nurse as a key provider, as case management. But some methodological concerns raise, above all, the design of the intervention (intensity, frequency, components, etc).
Methods/Design
Objectives: General: To develop the first and second phases (theorization and modeling) for designing a multifaceted case-management intervention in people with chronic conditions (COPD and heart failure) and their caregivers. Specific aims: 1) To identify key events in people living with chronic disease and their relation with the Health Care System, from their point of view. 2) To know the coping mechanisms developed by patients and their caregivers along the story with the disease. 3) To know the information processing and its utilization in their interactions with health care providers. 4) To detect potential unmet needs and the ways deployed by patients and their caregivers to resolve them. 5) To obtain a description from patients and caregivers, about their itineraries along the Health Care System, in terms of continuity, accessibility and comprehensiveness of care. 6) To build up a list of promising case-management interventions in patients with Heart Failure and COPD with this information in order to frame it into theoretical models for its reproducibility and conceptualization. 7) To undergo this list to expert judgment to assess its feasibility and pertinence in the Andalusian Health Care. Design: Qualitative research with two phases: For the first five objectives, a qualitative technique with biographic stories will be developed and, for the remaining objectives, an expert consensus through Delphi technique, on the possible interventions yielded from the first phase. The study will be developed in the provinces of AlmerĂa, Málaga and Granada in the Southern Spain, from patients included in the Andalusian Health Care Service database with the diagnosis of COPD or Heart Failure, with the collaboration of case manager nurses and general practitioners for the assessment of their suitability to inclusion criteria. Patients and caregivers will be interviewed in their homes or their Health Centers, with their family or their case manager nurse as mediator.
Discussion
First of a series of studies intended to design a case-management service for people with heart failure and COPD, in the Andalusian Health Care System, where case management has been implemented since 2002. Accordingly with the steps of a theoretical model for complex interventions, in this study, theorization and intervention modeling phases will be developed.This research was carried out with the support of one research grant, awarded by the Regional Health Ministry of Andalusia (Exp. 0222/2008
Controlled rippling of graphene via irradiation and applied strain modify its mechanical properties: a nanoindentation simulation study
Ripples, present in free standing graphene, have an important influence in the mechanical behavior of this two-dimensional material. In this work we show through nanoindentation simulations, how out-of-plane displacements can be modified by strain resulting in softening of the membrane under compression and stiffening under tension. Irradiation also induces changes in the mechanical properties of graphene. Interestingly, compressed samples, irradiated at low doses are stiffened by the irradiation while samples under tensile strain do not show significant changes in their mechanical properties. These simulations indicate that vacancies, produced by the energetic ions, cannot be the ones directly responsible for this behavior. However, changes in roughness induced by the momentum transferred from the energetic ions to the membrane, can explain these differences. These results provide an alternative explanation to recent experimental observations of stiffening of graphene under low dose irradiation, as well as paths to tailor the mechanical properties of this material via applied strain and irradiation.This work is supported by the Generalitat Valenciana through grant reference PROMETEO2012/011 and the Spanish government through grant FIS2010-21883. CJR and EMB thanks support from SeCTyP-UNCuyo grant M003, and ANPCyT grant PICT-2014-0696. CJR thanks CONICET and the 310 Group at FCEN-UNCuyo
ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy in borderline-resected pancreatic cancer
Radiation therapy (RT) is a valuable component of multimodal treatment for localized pancreatic cancer. Intraoperative radiation therapy (IORT) is a very precise RT modality to intensify the irradiation effect for cancer involving upper abdominal structures and organs, generally delivered with electrons (IOERT). Unresectable, borderline and resectable disease categories benefit from dose-escalated chemoradiation strategies in the context of active systemic therapy and potential radical surgery. Prolonged preoperative treatment may act as a filter for selecting patients with occult resistant metastatic disease. Encouraging survival rates have been documented in patients treated with preoperative chemoradiation followed by radical surgery and IOERT (>20 months median survival, >35% survival at 3 years). Intensive preoperative treatment, including induction chemotherapy followed by chemoradiation and an IOERT boost, appears to prolong long-term survival within the subset of patients who remain relapse-free for>2 years (>30 months median survival; >40% survival at 3 years). Improvement of local control through higher RT doses has an impact on the survival of patients with a lower tendency towards disease spread. IOERT is a well-accepted approach in the clinical scenario (maturity and reproducibility of results), and extremely accurate in terms of dose-deposition characteristics and normal tissue sparing. The technique can be adapted to systemic therapy and surgical progress. International guidelines (National Comprehensive Cancer Network or NCCN guidelines) currently recommend use of IOERT in cases of close surgical margins and residual disease. We hereby report the ESTRO/ACROP recommendations for performing IOERT in borderline-resectable pancreatic cancer
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Defining risk factors associated with difficult peripheral venous Cannulation: A systematic review and meta-analysis
Peripheral venous catheterization is a common technique in hospitals which is not always successful, resulting in multiple punctures and degradation of the vessels. This scenario, which we have termed 'difficult peripheral venous access', is associated to delays in care, obtention of samples or diagnosis, as well as a higher use of central catheters. This study intends to identify risk factors associated to the incidence of 'difficult peripheral venous access' in adults at hospital. We designed a systematic review of published studies (protocol PROSPERO 2018 CRD42018089160). We conducted structured electronic searches using key words and specific vocabulary, as well as directed searches in several databases. After validity analysis, we selected 7 studies with observational methodology. We found great variability in the definition of 'difficult peripheral venous access' and in the variables proposed as risk factors. Statistically significant factors through studies include demographic and anthropometric variables (gender, Body Mass Index), as well as medical and health conditions (diabetes, renal insufficiency, parenteral drug abuse, cancer chemotherapy), together with variables related to the vein or vascular access (vein visibility and palpability, vessel diameter, previous history of difficulty). Some studies have also considered variables related to the professional performing the technique. Meta-analyses were carried out for gender and obesity as potential risk factors. Only obesity appeared as a statistically significant risk factor with OR of 1.48; 95% CI (1.03 to 1.93; p = 0.016). Methodological heterogeneity prevented the development of further meta-analyses. It is essential to design future studies with diverse hospital populations, in which a wide selection of potential risk factors can be studied in a unique analysis. Our work identifies the most relevant variables that should be included in those studies
Local electroexfoliation of graphene with a STM tip
Graphite surfaces can be manipulated by several methods to create graphene structures of different shapes and sizes. Scanning tunneling microscopy (STM) can be used to create these structures either through mechanical contact between the tip and the surface or through electro-exfoliation. In the latter, the mechanisms involved in the process of exfoliation with an applied voltage are not fully understood. Here we show how a graphite surface can be locally exfoliated in a systematic manner by applying an electrostatic force with a STM tip at the edge of a terrace, forming triangular flakes several nanometers in length. We demonstrate, through experiments and simulations, how these flakes are created by a two-step process: first a voltage ramp must be applied at the edge of the terrace, and then the tip must be scanned perpendicularly to the edge. Ab-initio electrostatic calculations reveal that the presence of charges on the graphite surface weakens the interaction between layers allowing for exfoliation at voltages in the same range as those used experimentally. Molecular dynamics simulations show that a force applied locally on the edge of a step produces triangular flakes such as those observed under STM. Our results provide new insights towards surface modification that can be extended to other layered materials
Influence of environmental gradient on the distribution of macrobenthic communities in the Guadiana estuary
The present study on the distribution of sofbottom macrofauna along the Guadiana River and nearby areas has made it possible to differentiate among zones with different benthic community compositions in response to their environmental conditions. Five main areas were established: upper, middle, and lower estuary, mouth, and coastal area, which could also be divided into shallower and deeper communities. Because of the nonexistence of any obvious contaminant element, it seems that the differences found among the marine, freshwater and estuarine environments were the reason for the communities' heterogeneity. This was confirmed by multivariate analysis and by the clear enrichment and structuring gradient, from upper to coastal areas, in the communities.El estudio efectuado a lo largo del cauce del rĂo Guadiana y las áreas de influencia ha permitido establecer las zonas donde se desarrollan las distintas comunidades de macrofauna del sedimento como respuesta a las diversas condiciones ambientales. En este sentido, se han delimitado cinco grandes zonas: tramo alto, tramo medio, estuario bajo, desembocadura y área litoral, donde, a su vez, se distinguen las comunidades someras de las profundas. Ante la inexistencia de un elemento contaminante claro, parece que son las diferencias entre el medio marino, el fluvial y el estuarino las que están marcando las distintas composiciones de estas comunidades, como se pone de manifiesto en los análisis multivariantes realizados y por el gradiente de enriquecimiento y estructuraciĂłn conforme se alcanza un ambiente de mayor influencia marina.Instituto Español de OceanografĂ
Systematic review of the psychometric properties of patient-reported outcome measures for rheumatoid arthritis in the foot and ankle
Objective:
To identify self-reported outcome measures specific to the foot and ankle in patients with rheumatoid arthritis and to investigate the methodological quality and psychometric properties of these measures.
Method:
A systematic review focusing on patients with rheumatoid arthritis.
Setting:
The search was conducted in the PubMed, SCOPUS, CINAHL, PEDro and Google Scholar databases, based on the following inclusion criteria: population (with rheumatoid arthritis) > 18 years; psychometric or clinimetric validation studies of patient-reported outcomes specific to the foot and ankle, in different languages, with no time limit. Two of the present authors independently assessed the quality of the studies located and extracted the relevant data. Terwee’s criteria and the COSMIN checklist were employed to ensure adequate methodological quality.
Results:
Of the initial 431 studies considered, 14 met the inclusion criteria, representing 7,793 patients (56.8 years). These instruments were grouped into three dimensions (pain, perceived health status and quality of life and disability). The time to complete any of the PROMs varies around 15 minutes. PROMs criterias with the worst scores by COSMIN, 92.85% and 85.71% were criterion validity, measurement error, internal consistency and responsiveness. 28.57% of PROMs were compared with the measurement properties.
Conclusion:
the Self-Reported Foot and Ankle Score achieved the highest number of positive criteria (according to Terwee and COSMIN), and is currently the most appropriate for patients with Rheumatoid arthritis
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