264 research outputs found

    Temporal evolution of oscillating coronal loops

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    Context. Transverse oscillations of coronal structures are currently intensively studied to explore the associated magnetohydrodynamic wave physics and perform seismology of the local medium. Aims. We make a first attempt to measure the thermodynamic evolution of a sample of coronal loops that undergo decaying kink oscillations in response to an eruption in the corresponding active region. Methods. Using data from the six coronal wavelengths of SDO/AIA, we performed a differential emission measure (DEM) analysis of 15 coronal loops before, during, and after the eruption and oscillation. Results. We find that the emission measure, temperature, and width of the DEM distribution undergo significant variations on time scales relevant for the study of transverse oscillations. There are no clear collective trends of increases or decreases for the parameters we analysed. The strongest variations of the parameters occur during the initial perturbation of the loops, and the influence of background structures may also account for much of this variation. Conclusions. The DEM analysis of oscillating coronal loops in erupting active regions shows evidence of evolution on time scales important for the study of the oscillations. Further work is needed to separate the various observational and physical mechanisms that may be responsible for the variations in temperature, DEM distribution width, and total emission measure.Comment: Accepted in A&

    Stress dynamically regulates behavior and glutamatergic gene expression in hippocampus by opening a window of epigenetic plasticity

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    Excitatory amino acids play a key role in both adaptive and deleterious effects of stressors on the brain, and dysregulated glutamate homeostasis has been associated with psychiatric and neurological disorders. Here, we elucidate mechanisms of epigenetic plasticity in the hippocampus in the interactions between a history of chronic stress and familiar and novel acute stressors that alter expression of anxiety- and depressive-like behaviors. We demonstrate that acute restraint and acute forced swim stressors induce differential effects on these behaviors in naive mice and in mice with a history of chronic-restraint stress (CRS). They reveal a key role for epigenetic up- and down-regulation of the putative presynaptic type 2 metabotropic glutamate (mGlu2) receptors and the postsynaptic NR1/NMDA receptors in the hippocampus and particularly in the dentate gyrus (DG), a region of active neurogenesis and a target of antidepressant treatment. We show changes in DG long-term potentiation (LTP) that parallel behavioral responses, with habituation to the same acute restraint stressor and sensitization to a novel forced-swim stressor. In WT mice after CRS and in unstressed mice with a BDNF loss-of-function allele (BDNF Val66Met), we show that the epigenetic activator of histone acetylation, P300, plays a pivotal role in the dynamic up- and down-regulation of mGlu2 in hippocampus via histone-3-lysine-27-acetylation (H3K27Ac) when acute stressors are applied. These hippocampal responses reveal a window of epigenetic plasticity that may be useful for treatment of disorders in which glutamatergic transmission is dysregulated

    Weekly epirubicin plus lonidamine in advanced breast carcinoma

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    : Lonidamine has been demonstrated to potentiate the cytotoxic activity of several antineoplastic drugs, for example anthracyclines. Moreover, epirubicin is considered one of the most active drugs in advanced breast cancer, although optimal dose and schedule remains to be defined. In the present study we have treated 51 patients with advanced breast cancer with a combination of lonidamine (450 mg/day orally from day 1 throughout treatment) and epirubicin (25 mg/m2 i.v.) administered according to a weekly schedule for 24 weeks. Objective responses were observed in 29 out of 51 patients (57%; CR 16%, PR 41%). Liver metastases responded in eight out of 12 evaluable patients (67%). Average response duration was 12.4 months and median overall survival was 23 months (range 1-90+). Toxicity was negligible. The combination of weekly epirubicin and lonidamine is feasible and active in advanced breast cancer patients

    Bell inequalities as constraints on unmeasurable correlations

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    The interpretation of the violation of Bell-Clauser-Horne inequalities is revisited, in relation with the notion of extension of QM predictions to unmeasurable correlations. Such extensions are compatible with QM predictions in many cases, in particular for observables with compatibility relations described by tree graphs. This implies classical representability of any set of correlations , , , and the equivalence of the Bell-Clauser-Horne inequalities to a non void intersection between the ranges of values for the unmeasurable correlation associated to different choices for B. The same analysis applies to the Hardy model and to the "perfect correlations" discussed by Greenberger, Horne, Shimony and Zeilinger. In all the cases, the dependence of an unmeasurable correlation on a set of variables allowing for a classical representation is the only basis for arguments about violations of locality and causality.Comment: Some modifications have been done in order to improve clarity of presentation and comparison with other approache

    Laser in surgical scar clearance: An update review.

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    AbstractScar formation is a consequence of wound healing that developed from damaged tissue either from physical injury or surgical incision. A hypertrophic scar develops due to an abnormal healing response to trauma. It might lead to serious functional and cosmetic disability. There are numerous methods mentioned in the literature to treat such scars but to date, no single method has been known to cure them. In this review, we focused on differences between various types of nonsurgical management of hypertrophic scar focusing on the indication, mechanism of action, and efficacy of the pulsed dye laser (PDL), fractional carbon dioxide laser (fCO2), Er‐YAG laser, and intense pulse light (IPL). The literature research included peer‐reviewed articles (clinical trials or scientific reviews) which were identified by searching electronic databases like PubMed till January 2021 and reference lists of respective articles. Only articles published in the English language were included

    Breast cancer and timing of surgery during menstrual cycle: a 5-year analysis of 248 premenopausal women

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    : In the present report, we retrospectively analyzed the impact of the timing of surgery during menstrual cycle on disease-free and overall survival of 248 premenopausal patients with stage I/II breast cancer who underwent surgery followed by anthracycline-containing adjuvant chemotherapy. With a median follow-up of 5 years, no statistically significant differences were observed in disease-free or overall survival between women operated upon during the follicular (days 0-14) and the luteal (days 15-32) phase of the menstrual cycle. The impact on disease-free and overall survival of lymph-node status, tumor size and hormone receptor expression, but not of the phase of the menstrual cycle at the time of surgery, was confirmed by univariate and multivariate analysis. However, when combined with hormone receptor status, the phase of the menstrual cycle at the time of surgery proved useful to better define the prognosis of primary breast cancer patients, with significantly longer disease-free and overall survival for patients operated upon during the follicular phase and with positive hormone receptors

    Clinical significance of PTEN and p-Akt co-expression in HER2-positive metastatic breast cancer patients treated with trastuzumab-based therapies

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    Objective: The phosphatase and tensine homologue gene (PTEN) plays a crucial role in proliferation and survival of cancer cells by antagonizing the function of phosphatidylinositol 3'-kinase (PI3K), which, in turn, results in decreased Akt activity. We investigated the clinical impact of the expression of PTEN, p-Akt and PI3K in HER2-positive metastatic breast cancer (MBC) patients treated with trastuzumab-based therapies. Methods: Seventy-three patients treated with trastuzumab-based therapies were included and followed prospectively. PTEN, p-Akt and PI3K expression was determined by immunohistochemistry. Results: PTEN, p-Akt and PI3K resulted positive in 48%, 71% and 46.5% of patients, respectively. A significant correlation between PTEN and p-Akt (kappa 0.22, p = 0.03) and p-Akt and PI3K (kappa 0.20, p = 0.05) was observed. PTEN-positive patients had a progression-free survival (PFS) longer than PTEN-negative ones (p = 0.06). When grouped together, patients co-expressing PTEN and p-Akt had a statistically significant longer PFS as compared to the rest of patients (p = 0.01). At the multivariate analysis, PTEN and p-Akt co-expression was an independent predictor of lower risk of progression (hazard ratio 0.53, p = 0.05). Conclusion: In HER2-positive MBC, basal co-expression of PTEN and p-Akt might identify those patients who are more likely to benefit from trastuzumab-based therapies

    Explosive events - swirling transition region jets

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    In this paper, we extend our earlier work to provide additional evidence for an alternative scenario to explain the nature of so-called `explosive events'. The bi-directed, fast Doppler motion of explosive events observed spectroscopically in the transition region emission is classically interpreted as a pair of bidirectional jets moving upward and downward from a reconnection site. We discuss the problems of such a model. In our previous work, we focused basically on the discrepancy of fast Doppler motion without detectable motion in the image plane. We now suggest an alternative scenario for the explosive events, based on our observations of spectral line tilts and bifurcated structure in some events. Both features are indicative of rotational motion in narrow structures. We explain the bifurcation as the result of rotation of hollow cylindrical structures and demonstrate that such a sheath model can also be applied to explain the nature of the puzzling `explosive events'. We find that the spectral tilt, the lack of apparent motion, the bifurcation, and a rapidly growing number of direct observations support an alternative scenario of linear, spicular-sized jets with a strong spinning motion.Comment: 9 pages, 3 figures, accepted for publication in Solar Physic
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