2,569 research outputs found

    Unification of Constant-roll Inflation and Dark Energy with Logarithmic R2R^2-corrected and Exponential F(R)F(R) Gravity

    Full text link
    In this paper we investigate how to describe in a unified way a constant-roll inflationary era with a dark energy era, by using the theoretical framework of F(R)F(R) gravity. To this end, we introduce some classes of appropriately chosen F(R)F(R) gravity models, and we examine in detail how the unification of early and late-time acceleration eras can be achieved. We study in detail the inflationary era, and as we demonstrate it is possible to achieve a viable inflationary era, for which the spectral index of primordial curvature perturbations and the scalar-to-tensor ratio can be compatible with the latest observational data. In addition, the graceful exit issue is briefly discussed for a class of models. Finally, we discuss the dark energy oscillations issue, and we investigate which model from one of the classes we introduced, can produce oscillations with the smallest amplitude.Comment: Nuclear Physics B accepte

    Insights from the classical MD simulations

    Get PDF
    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)–glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898–915 (2011)]. These structures are stabilized by the short +N–H⋯O− bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm−1. It is caused by the asymmetric stretching vibrations of the +N–H⋯O− fragment. Result of the present paper suggests that infrared spectroscopy in the 2000–2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic studies of peptides and proteins

    NAILFOLD VIDEOCAPILLAROSCOPY FEATURES OF PATIENTS WITH ANTISYNTHETASE SYNDROME

    Get PDF
    Background: Antisynthetase syndrome (ASSD) is an autoimmune disease characterized by the clinical triad arthritis, myositis, and interstitial lung disease (ILD). As in inflammatory myopathies, nailfold videocapillaroscopy (NVC) alterations have been sporadically described also in ASSD patients, but no elucidating data are available. Objectives: To investigate the possible specific NVC features of ASSD patients. Methods: Within the framework of a multicenter study, we retrospectively analyzed NVC images of ASSD patients, after excluding patients with overlap syndrome with systemic sclerosis. Two operators in a blind manner re-evaluated all patients with at least one image per finger. For each patient, we examined number of capillaries (mean number of capillaries per mm in the distal row), enlarged and giant capillaries, micro-hemorrhages, avascular areas, ramified capillaries, and the presence of a scleroderma (SSc)-like pattern, according to manfredi et al. Finally, we correlated NVC features with clinical and serological findings of ASSD patients. Results: The NVC of 54 ASSD patients were analyzed (males/females 1/6.8, mean age 55.79, CI95% 51.9\u201359.9 years, mean disease duration 59.4, CI95% 27.9\u201390.9 months). Raynaud's phenomenon (RP) was recorded in 51.9% of patients, arthritis in 79.6%, myositis in 53.7%, and ILD in 92.6%. NVC alterations were observed in 53.7% of AASD patients. Nineteen patients (35.2%) showed a SSc-like pattern; the main features were disarrangement of hairpin and angiogenetic aspects (42.6%), avascular areas (38.9%), giant capillaries (27.6%), and microhemorrhages (20.4%). Finally, the mean number of capillaries was reduced (7.8\ub12/mm). No significant association was recorded between SSc-like pattern and the presence of arthritis, myositis, and ILD, nor with RP. Among other NVC features, angiogenesis was significantly associated to female gender (p=0.031), while microhemorrhages were inversely associated to the presence of arthritis (0.033). No association was observed between NVC features and autoantibodies profile. Of interest, in 58% of patients with ILD we observed at least a NVC alteration vs no patients without ILD (p=0.04). Finally, in patients with RP NVC alterations were recorded in 15/28 patients (53.6%) and a SSc-like pattern in 11/28 (39.3%), while only 57.9% of patients with SSc-like pattern had a clinically manifest Raynaud's phenomenon. Conclusions: Despite preliminary, the present is the first study concerning NVC in AASD patients. Regardless of the presence of Raynaud's phenomenon, NVC alterations are frequently observed; in particular, a SSc-like pattern is recorded in more than 1/3 of patients. NVC should be performed in all ASSD patients at diagnosis regardless of the presence of RP in the patient history and during follow-up. ASSD should be always considered in the screening of RP. A prospective multicenter study has been planned to identify specific patterns and possible associations between NVC findings and clinical and serological features of ASSD

    Nailfold videocapillaroscopy in antisynthetase syndrome

    Get PDF
    A 57-year-old woman with a diagnosis of antisynthetase syndrome (ASSD) underwent a nailfold videocapillaroscopy (NVC) showing a scleroderma pattern. Alterations in capillary morphology have been reported in adults with inflammatory myositis (IM) but only recently have the differences in NVC findings between these two diseases been established. ASSD is currently classified as a subset of IM, for which reason only a few studies in literature evaluate its specific hallmarks, showing nonspecific features of NVC in patients with polymyositis and dermatomyositis (DM) and antisynthetase antibodies. To our knowledge, this is the first description of ASSD capillaroscopy features, and the first report of NVC in ASSD with evidence of scleroderma pattern. Further studies are needed to define clearly frequency, typical features, and possible correlation with clinical and serological data of NVC changes in ASSD, differences between microangiopathy in ASSD and systemic sclerosis or DM

    Nailfold videocapillaroscopy in antisynthetase syndrome

    Get PDF
    A 57-year-old woman with a diagnosis of antisynthetase syndrome (ASSD) underwent a nailfold videocapillaroscopy (NVC) showing a scleroderma pattern. Alterations in capillary morphology have been reported in adults with inflammatory myositis (IM) but only recently have the differences in NVC findings between these two diseases been established. ASSD is currently classified as a subset of IM, for which reason only a few studies in literature evaluate its specific hallmarks, showing nonspecific features of NVC in patients with polymyositis and dermatomyositis (DM) and antisynthetase antibodies. To our knowledge, this is the first description of ASSD capillaroscopy features, and the first report of NVC in ASSD with evidence of scleroderma pattern. Further studies are needed to define clearly frequency, typical features, and possible correlation with clinical and serological data of NVC changes in ASSD, differences between microangiopathy in ASSD and systemic sclerosis or DM

    Modules of Abelian integrals and Picard-Fuchs systems

    Full text link
    We give a simple proof of an isomorphism between the two C[t]\mathbb{C}[t]-modules: the module of relative cohomologies Λ2/dH∧Λ1\Lambda^2/dH\land \Lambda^1 and the module of Abelian integrals corresponding to a regular at infinity polynomial HH in two variables. Using this isomorphism, we prove existence and deduce some properties of the corresponding Picard-Fuchs system.Comment: A separate section discusses Fuchsian properties of the Picard-Fuchs system, Morse condition exterminated. Few errors were correcte

    Ion diffusion modelling of Fricke-agarose dosemeter gels

    Get PDF
    In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effect

    Increased incidence of breast cancer in postmenopausal women with high body mass index at the modena screening program

    Get PDF
    Purpose: We conducted a study to evaluate the relationship between body mass index (BMI) and the risk of breast cancer (BC) and outcome in a population of 14,684 women aged 55 to 69 years eligible to participate in the Mammography Screening Program (MSP) in the Province of Modena, Italy. Methods: The study population was drawn from women who underwent mammography screening between 2004 and 2006 in the Province of Modena. Women were subdivided into obese, overweight, and normal-weight categories according to BMI and followed until July 31, 2010, to evaluate the BC incidence. The clinicopathological characteristics of BC were also evaluated in different groups of patients classified according to BMI. After BC diagnosis, patients were followed for a median period of 65 (range, 2\u2013104) months. Second events (recurrences and second tumors) were recorded, and the 5-year event-free survival (EFS) was calculated. Results: After a period of 73 months, 366 cases of BC were diagnosed. Compared with normal-weight women, obese women had a significantly higher incidence of BC (relative risk [RR], 1.32; p= 0.040) (RR=1), larger tumors (27% of tumors were larger than T2 size), and more nodal involvement (38.5% of tumors were node-positive). Furthermore, a significantly higher rate of total events was seen in obese women compared with overweight and normal-weight patients, respectively (17.9% vs. 11.4% vs. 10.8%, p=0.032). The 5-year EFS was 89.0%, 89.0%, and 80.0% for normal-weight, overweight, and obese patients, respectively. Conclusion: We observed a significantly higher risk of BC in obese women among those eligible to participate in the MSP in the Province of Modena. Finally, obese women had more second events and poorer EFS compared to nono bese women

    Wettability of soft PLGA surfaces predicted by experimentally augmented atomistic models

    Get PDF
    A challenging topic in surface engineering is predicting the wetting properties of soft interfaces with different liquids. However, a robust computational protocol suitable for predicting wettability with molecular precision is still lacking. In this article, we propose a workflow based on molecular dynamics simulations to predict the wettability of polymer surfaces and test it against the experimental contact angle of several polar and nonpolar liquids, namely water, formamide, toluene, and hexane. The specific case study addressed here focuses on a poly(lactic-co-glycolic acid) (PLGA) flat surface, but the proposed experimental-modeling protocol may have broader fields of application. The structural properties of PLGA slabs have been modeled on the surface roughness determined with microscopy measurements, while the computed surface tensions and contact angles were validated against standardized characterization tests, reaching a discrepancy of less than 3% in the case of water. Overall, this work represents the initial step toward an integrated multiscale framework for predicting the wettability of more complex soft interfaces, which will eventually take into account the effect of surface topology at higher scales and synergically be employed with experimental characterization techniques
    • …
    corecore