114 research outputs found

    Self-Organized Criticality Driven by Deterministic Rules

    Full text link
    We have investigated the essential ingredients allowing a system to show Self Organized Criticality (SOC) in its collective behavior. Using the Bak-Sneppen model of biological evolution as our paradigm, we show that the random microscopic rules of update can be effectively substituted with a chaotic map without changing the universality class. Using periodic maps SOC is preserved, but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: 4 pages, RevTex (tar.gz), 4 eps-figures include

    Drug-drug interactions between palbociclib and proton pump inhibitors may significantly affect clinical outcome of metastatic breast cancer patients

    Get PDF
    BACKGROUND: Proton-pump-inhibitors (PPIs) are frequently prescribed for the management of anticancer drug-related gastrointestinal symptoms. Palbociclib is a weak base with pH-dependent solubility and potential drug-drug interaction at the absorption level may affect clinical pharmacokinetics. The current study was aimed at investigating the effect of co-administration of PPIs and palbociclib on progression-free survival (PFS) in metastatic breast cancer (mBC) patients. PATIENTS AND METHODS: Patients affected by estrogen receptor-positive, human epidermal growth factor receptor 2-negative mBC, who were candidates for first-line treatment with palbociclib, were enrolled in this retrospective observational study. Patients were defined as ‘no concomitant PPIs’ if no PPIs were administered during palbociclib treatment, and as ‘concomitant PPIs’ if the administration of PPIs covered the entire or not less than two-thirds of treatment with palbociclib. All clinical interventions were made according to clinical practice. RESULTS: A total of 112 patients were enrolled in the study; 56 belonged to the ‘no concomitant PPIs’ group and 56 to the ‘concomitant PPIs’ group. Seventy-one patients were endocrine-sensitive and received palbociclib and letrozole, and 43 were endocrine-resistant and were treated with palbociclib and fulvestrant. The most prescribed PPI was lansoprazole. Patients taking PPIs had a shorter PFS than those taking palbociclib and endocrine therapy alone (14.0 versus 37.9 months, P 2 hematological toxicities [Common Terminology Criteria for Adverse Events (CTCAE) scale]. CONCLUSIONS: The present study demonstrates that concomitant use of PPIs in mBC patients treated with palbociclib has a detrimental effect on PFS. Therefore, it is recommended to prescribe PPIs with caution in these patients, strictly adhering to the indications in the summary of product characteristics (RCP)

    Psychosocial care for adult cancer patients: guidelines of the Italian Medical Oncology Association

    Get PDF
    SIMPLE SUMMARY: People with cancer often experience psychological and social needs, related to their disease and treatments, that can negatively impact quality of life. Various social interventions can be helpful but are not always offered to patients who would benefit from them. This guideline aims to help oncology professionals address the psychosocial aspects of their adult patients and of those who care for them. It was compiled by a multidisciplinary panel, including patients, using rigorous methodology. Topics include patient information and communication, screening and management of psychosocial needs, and caregiver support. In particular, evidence emphasizes that nurses play a central role in providing psychosocial care and information for cancer patients, and that Physician communication skills must be improved with specific evidence-based training. In addition, psychosocial needs must be promptly detected and managed, especially with appropriate non-pharmacological interventions. ABSTRACT: Psychosocial morbidity can have negative consequences for cancer patients, including maladaptive coping, poor treatment adherence, and lower quality of life. Evidence shows that psychosocial interventions can positively impact quality of life, as well as symptoms and side effects; however, they are not always offered to patients who might benefit from them. These guidelines were produced by a multidisciplinary panel of 16 experts, including patients, following GRADE methodology. The panel framed clinical questions and voted on outcomes to investigate. Studies identified by rigorous search strategies were assessed to rate certainty of evidence, and recommendations were formulated by the panel. Although the quality of the evidence found was generally moderate, interventions could be recommended aimed at improving patient information, communication with healthcare professionals and involvement in decision-making; detecting and managing patient psychosocial needs, particularly with non-pharmacological therapy; and supporting families of patients with advanced cancer. The role of nurses as providers of information and psychosocial care is stressed. Most recommended interventions do not appear to necessitate new services or infrastructures, and therefore do not require allocation of additional resources, but predominantly involve changes in clinical staff behavior and/or ward organization. Patients should be made aware of psychosocial care standards so that they can expect to receive them

    Tri-critical behavior in rupture induced by disorder

    Full text link
    We discover a qualitatively new behavior for systems where the load transfer has limiting stress amplification as in real fiber composites. We find that the disorder is a relevant field leading to tri--criticality, separating a first-order regime where rupture occurs without significant precursors from a second-order regime where the macroscopic elastic coefficient exhibit power law behavior. Our results are based on analytical analysis of fiber bundle models and numerical simulations of a two-dimensional tensorial spring-block system in which stick-slip motion and fracture compete.Comment: Revtex, 10 pages, 4 figures available upon reques

    Self-organized criticality in deterministic systems with disorder

    Full text link
    Using the Bak-Sneppen model of biological evolution as our paradigm, we investigate in which cases noise can be substituted with a deterministic signal without destroying Self-Organized Criticality (SOC). If the deterministic signal is chaotic the universality class is preserved; some non-universal features, such as the threshold, depend on the time correlation of the signal. We also show that, if the signal introduced is periodic, SOC is preserved but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: RevTex, 8 pages, 8 figure

    Cross-cultural adaptation and patients' judgments of a Question Prompt List for Italian-speaking cancer patients

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Question Prompt Lists (QPLs) have proven very effective in encouraging cancer patients to ask questions, allowing them to take up a more active role during visits with the oncologist. As no such tool has yet been validated for Italian-speaking users, we carried out the cross-cultural adaptation and evaluation of an existing Australian Question Prompt List.</p> <p>Methods</p> <p>Cross-cultural adaptation was performed in accordance with the five steps described by Guillemin and Beaton. Forward and back translations of the original tool were carried out, and the products discussed by an Expert Committee who agreed on a prefinal version of the Italian QPL, which was submitted to 30 volunteer patients for evaluation. They rated each question's adequacy of content, clarity of wording, usefulness, and generated anxiety, on a 3-point Likert scale. Based on the analysis of patient ratings, the final version of the Italian QPL was produced.</p> <p>Results</p> <p>Few discrepancies between the two back translations and the original version of the instrument were noted, indicating that the Italian translation (synthesis of the 2 forward translations) was substantially accurate. Most volunteer patients felt that the questionnaire was adequate, easy to understand and useful. Only a few minor criticisms were expressed. Certain questions on diagnosis and prognosis generated the highest level of anxiety. Patient comments and ratings on clarity highlighted the need to clarify common health care terms which are not widely used by the public (i.e. guideline, multidisciplinary team and clinical trial)</p> <p>Conclusions</p> <p>This cross-cultural adaptation has produced an Italian Question Prompt List that is now available for multi-center international studies and can be safely used with Italian-speaking cancer patients.</p

    Avalanches in Breakdown and Fracture Processes

    Full text link
    We investigate the breakdown of disordered networks under the action of an increasing external---mechanical or electrical---force. We perform a mean-field analysis and estimate scaling exponents for the approach to the instability. By simulating two-dimensional models of electric breakdown and fracture we observe that the breakdown is preceded by avalanche events. The avalanches can be described by scaling laws, and the estimated values of the exponents are consistent with those found in mean-field theory. The breakdown point is characterized by a discontinuity in the macroscopic properties of the material, such as conductivity or elasticity, indicative of a first order transition. The scaling laws suggest an analogy with the behavior expected in spinodal nucleation.Comment: 15 pages, 12 figures, submitted to Phys. Rev. E, corrected typo in authors name, no changes to the pape
    • 

    corecore