58 research outputs found
Some peculiarities of motion of neutral and charged test particles in the field of a spherically symmetric charged object in General Relativity
We propose the method of investigation of radial motions for charged and
neutral test particles in the Reissner-Nordstr\"{o}m field by means of mass
potential. In this context we analyze special features of interaction of
charges and their motions in General Relativity and construct the radial motion
classification. For test particles and a central source with charges and
, respectively, the conditions of attraction (when ) and repulsion
(when ) are obtained. The conditions of motionless test particle states
with respect to the central source are investigated and, in addition, stability
conditions for such static equilibrium states are found. It is shown that
stable states are possible only for the bound states of weakly charged
particles in the field of a naked singularity. Frequencies of small
oscillations of test particles near their equilibrium positions are also found.Comment: 15 pages, 9 figure
Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis (TRIPOD):Explanation and Elaboration. Translation into Russian
The TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis) Statement includes a 22-item checklist, which aims to improve the reporting of studies developing, validating, or updating a prediction model, whether for diagnostic or prognostic purposes. The TRIPOD Statement aims to improve the transparency of the reporting of a prediction model study regardless of the study methods used. This explanation and elaboration document describes the rationale; clarifies the meaning of each item; and discusses why transparent reporting is important, with a view to assessing risk of bias and clinical usefulness of the prediction model. Each checklist item of the TRIPOD Statement is explained in detail and accompanied by published examples of good reporting. The document also provides a valuable reference of issues to consider when designing, conducting, and analyzing prediction model studies. To aid the editorial process and help peer reviewers and, ultimately, readers and systematic reviewers of prediction model studies, it is recommended that authors include a completed checklist in their submission. The TRIPOD checklist can also be downloaded from www.tripod-statement.org.</p
Local Literature Bias in Genetic Epidemiology: An Empirical Evaluation of the Chinese Literature
BACKGROUND: Postulated epidemiological associations are subject to several biases. We evaluated whether the Chinese literature on human genome epidemiology may offer insights on the operation of selective reporting and language biases. METHODS AND FINDINGS: We targeted 13 gene-disease associations, each already assessed by meta-analyses, including at least 15 non-Chinese studies. We searched the Chinese Journal Full-Text Database for additional Chinese studies on the same topics. We identified 161 Chinese studies on 12 of these gene-disease associations; only 20 were PubMed-indexed (seven English full-text). Many studies (14–35 per topic) were available for six topics, covering diseases common in China. With one exception, the first Chinese study appeared with a time lag (2–21 y) after the first non-Chinese study on the topic. Chinese studies showed significantly more prominent genetic effects than non-Chinese studies, and 48% were statistically significant per se, despite their smaller sample size (median sample size 146 versus 268, p < 0.001). The largest genetic effects were often seen in PubMed-indexed Chinese studies (65% statistically significant per se). Non-Chinese studies of Asian-descent populations (27% significant per se) also tended to show somewhat more prominent genetic effects than studies of non-Asian descent (17% significant per se). CONCLUSION: Our data provide evidence for the interplay of selective reporting and language biases in human genome epidemiology. These biases may not be limited to the Chinese literature and point to the need for a global, transparent, comprehensive outlook in molecular population genetics and epidemiologic studies in general
Myricetin induces pancreatic cancer cell death via the induction of apoptosis and inhibition of the phosphatidylinositol 3-kinase (PI3K) signaling pathway
Pancreatic cancer is the fourth leading cause of cancer related deaths and is a disease with poor prognosis. It is refractory to standard chemotherapeutic drugs or to novel treatment modalities, making it imperative to find new treatments. In this study, using both primary and metastatic pancreatic cancer cell lines, we have demonstrated that the flavonoid myricetin induced pancreatic cancer cell death
in vitro via apoptosis, and caused a decrease in PI3 kinase activity.
In vivo, treatment of orthotopic pancreatic tumors with myricetin resulted in tumor regression and decreased metastatic spread. Importantly, myricetin was non-toxic, both
in vitro and
in vivo, underscoring its use as a therapeutic agent against pancreatic cancer
Epidermal Growth Factor Receptor Inhibitor–Induced Hypomagnesemia: A Survey of Practice Patterns among Canadian Gastrointestinal Medical Oncologists
Background: The optimal management of hypomagnesemia (hMg) induced by epidermal growth factor receptor inhibitors (EGFRIS) for advanced colorectal cancer is unclear. We surveyed gastrointestinal medical oncologists in Canada to determine practice patterns for the management of EGFRI-induced hMg. Methods: Based on distribution lists from the Eastern Canadian Colorectal Cancer Consensus Conference and the Western Canadian Gastrointestinal Cancer Consensus Conference, medical oncologists were invited to participate in an online questionnaire between November 2013 and February 2014. Results: From the 104 eligible physicians, 40 responses were obtained (38.5%). Panitumumab was more commonly prescribed than cetuximab by 70% of respondents, with 25% prescribing cetuximab and panitumumab equally. Most respondents obtain a serum magnesium level before initiating a patient on an EGFRI (92.5%) and before every treatment (90%). Most use a reactive strategy for magnesium supplementation (90%) and, when using supplementation, favour intravenous (IV) alone (40%) or IV and oral (45%) dosing. Magnesium sulfate was used for IV replacement, and the most common oral strategies were magnesium oxide (36.4%) and magnesium rougier (18.2%). Under the reactive strategy, intervention occurred at hMg grade 1 (70.3%) or grade 2 (27%). Of the survey respondents, 45% felt that 1–5 of their patients have ever developed symptoms attributable to hMg, and 35% have had to interrupt EGFRI therapy because of this toxicity, most commonly at grade 3 (30%) or grade 4 (45%) hMg. The most important question about EGFRI-induced hMg was its relevance to clinical outcomes (45%) and its symptoms (37.5%). Conclusions: In Canada, various strategies are used in the management of EGFRI-induced hMg, including prophylactic and reactive approaches that incorporate IV, oral, or a combination of IV and oral supplementation. Clinicians are concerned about the effect of hMg on clinical outcomes and about the symptoms that patients experience as a result of this toxicity
Risk and predictors of suicide in colorectal cancer patients: a Surveillance, Epidemiology, and End Results analysis
The impact of ideas and time on policy solutions: Maintaining institutional autonomy and the second runway at Manchester Airport
The important interrelationships between problems, ideas and time mean that there can be several facets to institutional vulnerability. Thus conditions at a moment in time can make an institution open to the introduction of new ideas, but these ideas may compete over time. In this context, a policy problem may demand a solution that satisfies the immediate situation, but can find itself overtaken by the effects of time. The case study examines an environmental mitigation package signed in association with construction of the second runway at Manchester Airport. The instrument attempted to deal with two competing ideas in the form of economic growth and sustainable development. However, economic growth was firmly grounded in the institutional strength of the Airport, while the demands of sustainable development required careful management over time. The article concludes that time emerges as a powerful variable in shifting the terms of the policy debate. © Blackwell Publishing Ltd. 2005
- …