825 research outputs found
Modern meson--exchange potential and superfluid neutron star crust matter
In this work we study properties of neutron star crusts, where matter is
expected to consist of nuclei surrounded by superfluid neutrons and a
homogeneous background of relativistic electrons. The nuclei are disposed in a
Coulomb lattice, and it is believed that the structure of the lattice
influences considerably the specific heat of the neutronic matter inside the
crust of a neutron star. Using a modern meson--exchange potential in the
framework of a local--density approximation we calculate the neutronic specific
heat accounting for various shapes of the Coulomb lattice, from spherical to
non--spherical nuclear shapes. We find that a realistic nucleon--nucleon
potential leads to a significant increase in the neutronic specific heat with
respect to that obtained assuming a uniform neutron distribution. The increase
is largest for the non--spherical phase of the crust. These results may have
consequences for the thermal history of young neutron stars.Comment: Revtex, 5 pages, 4 figures included as uuencoded p
Microscopic structure of a vortex line in superfluid neutron star matter
The microscopic structure of an isolated vortex line in superfluid neutron
star matter is studied by solving the Bogoliubov-de Gennes equations. Our
calculation, which is the starting point for a microscopic calculation of
pinning forces in neutron stars, shows that the size of the vortex core varies
differently with density, and is in general smaller than assumed in some
earlier calculations of vortex pinning in neutron star crusts. The implications
of this result are discussedComment: 5 pages, 2 figure
R-modes in Neutron Stars with Crusts: Turbulent Saturation, Spin-down, and Crust Melting
Rossby waves (r-modes) have been suggested as a means to regulate the spin
periods of young or accreting neutron stars, and also to produce observable
gravitational wave radiation. R-modes involve primarily transverse,
incompressive motions of the star's fluid core. However, neutron stars gain
crusts early in their lives: therefore, r-modes also imply shear in the fluid
beneath the crust. We examine the criterion for this shear layer to become
turbulent, and derive the rate of dissipation in the turbulent regime. Unlike
dissipation from a viscous boundary layer, turbulent energy loss is nonlinear
in mode energy and can therefore cause the mode to saturate at amplitudes
typically much less than unity. This energy loss also reappears as heat below
the crust. We study the possibility of crust melting as well as its
implications for the spin evolution of low-mass X-ray binaries. Lastly, we
identify some universal features of the spin evolution that may have
observational consequences.Comment: 12 pages, 4 figures, submitted to Ap
The beneficial effects of essential oils in anti-obesity treatment
Obesity is a complex disease caused by an excessive amount of body fat. Obesity is a medical problem and represents an important risk factor for the development of serious diseases such as insulin resistance, type 2 diabetes, cardiovascular disease, and some types of cancer. Not to be overlooked are the psychological issues that, in obese subjects, turn into very serious pathologies, such as depression, phobias, anxiety, and lack of self-esteem. In addition to modifying one’s lifestyle, the reduction of body mass can be promoted by different natural compounds such as essential oils (EOs). EOs are mixtures of aromatic substances produced by many plants, particularly in medicinal and aromatic ones. They are odorous and volatile and contain a mixture of terpenes, alcohols, aldehydes, ketones, and esters. Thanks to the characteristics of the various chemical components present in them, EOs are used in the food, cosmetic, and pharmaceutical fields. Indeed, it has been shown that EOs possess great antibiotic, anti-inflammatory, and antitumor powers. Emerging results also demonstrate the anti-obesity effects of EOs. We have examined the main data obtained in experimental studies and, in this review, we summarize the effect of EOs in obesity and obesityrelated metabolic diseases
Efficacy of a preparation based on calcium butyrate, bifidobacterium bifidum, bifidobacterium lactis, and fructooligosaccharides in the prevention of relapse in ulcerative colitis: A prospective observational study
Several compounds based on short chain fatty acids and/or probiotics/prebiotics have shown promising results in the therapy of ulcerative colitis (UC), possibly due to its key role in restoring gut homeostasis as well as intestinal barrier integrity. Here, we investigated the efficacy of a patented preparation based on calcium butyrate, Bifidobacterium bifidum, Bifidobacterium lactis, and fructooligosaccharides (FEEDColon(®), Princeps, Cuneo, Italy) in maintaining remission and improving subjective symptoms and inflammatory indices in patients with UC receiving 5-ASA therapy. A total of 42 patients were prospectively recruited and randomized in 21 patients receiving combination therapy with mesalamine (5-ASA) plus FEEDColon(®) and 21 patients treated with standard 5-ASA therapy. Patients were assessed at baseline, at 6-month, and 12-month follow-up (FU). Therapeutic success (defined as Mayo partial score ≤ 2 and faecal calprotectin (FC) < 250 µg/g at 12-month FU) was reached by 32 (76%) patients: 20 (95%) among those treated with 5-ASA + FeedColon(®), and 12 (57%) among those treated with 5-ASA only (p = 0.009). Consistently, patients treated with combination therapy improved subjective symptoms (quality of life, abdominal pain, and stool consistency) and reduced FC values, while those treated with 5-ASA alone, improved neither subjective symptoms nor FC during the FU. In conclusion, FEEDColon(®) supplementation appears to be a valid add-on therapy for the maintenance of remission in patients with UC. Further multicentre, placebo-controlled, double-blind clinical trials are needed to validate our results on larger cohorts of patients with UC
In human retinoblastoma Y79 cells okadaic acid\u2013parthenolide co-treatment induces synergistic apoptotic effects, with PTEN as a key player.
Retinoblastoma is the most common intraocular malignancy of childhood. In developing countries, treatment is
limited, long-term survival rates are low and current chemotherapy causes significant morbidity to pediatric patients and significantly limits dosing. Therefore there is an urgent need to identify new therapeutic strategies to improve the clinical outcome of patients with retinoblastoma. here, we investigated the effects of two natural compounds okadaic acid (OKa) and parthenolide (PN) on human retinoblastoma Y79 cells. For the first time we showed that OKa/PN
combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by lowering in p-akt levels,
increasing in the stabilized forms of p53 and potent decrease in ps166-Mdm2. We also showed the key involvement
of PTeN which, after OKa/PN treatment, potently increased before p53, thus suggesting that p53 activation was under
PTeN action. Moreover, after PTEN-knockdown p-akt/ ps166Mdm2 increased over basal levels and p53 significantly lowered, while OKa/PN treatment failed both to lower p-akt and ps166-Mdm2 and to increase p53 below/over their basal levels respectively. OKa/PN treatment potently increased ROs levels whereas decreased those of Gsh. Reducing cellular Gsh by l-butathionine-[s,R]-sulfoximine treatment significantly anticipated the cytotoxic effect exerted by OKa/
PN. Furthermore, the effects of OKa/PN treatment on both Gsh content and cell viability were less pronounced in PTeN
silenced cells than in control cells. The results provide strong suggestion for combining a treatment approach that targets the PTeN/akt/Mdm2/p53 pathway
Okadaic acid-Parthenolide combination at subtoxic doses induces potent synergistic apoptotic effects in human retinoblastoma Y79 cells by upregulating PTEN.
Retinoblastoma is the most common intraocular malignancy afflicting children. The incidence is higher in developing countries, where treatment is limited and long-term survival rates are low. Vincristine, etoposide, and carboplatin -the agents commonly used in the treatment of retinoblastoma- determine side effects causing significant morbidity to pediatric patients and significantly limiting dosing. Thus, identifying new drugs and molecular targets to facilitate the development of novel therapeutics, and finding natural drug combinations to kill cancer cells by synergistically acting at subtoxic doses, may be a good goal. Here, we investigated the effects of two natural compounds, okadaic acid (OKA) and parthenolide (PN), in human retinoblastoma Y79 cells. We showed that OKA/PN combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by decrease in p-Akt, increase in the stabilized p53 forms and potent decrease in pS166\u2013Mdm2. We also showed the key involvement of PTEN which, after OKA/PN treatment, potently increased before p53, suggesting that p53 activation was under PTEN action. PTEN-knockdown increased p-Akt/ pS166Mdm2 over basal levels and significantly lowered p53, while OKA/PN treatment failed both to lower p-Akt and pS166\u2013Mdm2 and to increase p53 below/over their basal levels respectively. OKA/PN treatment potently increased ROS levels while decreased those of GSH. Reducing cellular GSH by butathionine-sulfoximine treatment significantly anticipated the cytotoxic effect exerted by OKA/PN. The effects of OKA/PN treatment on both GSH content and cell viability were less pronounced in PTEN silenced cells than in control cells. Our study reports for the first time both a synergistic apoptotic action between OKA and PN and the involvement of PTEN as key player in the apoptotic mechanism in human retinoblastoma Y79 cells. The results provide strong suggestion for combined inhibition of the PTEN/Akt/Mdm2/p53 pathway
Effects of a walking aid in COPD patients receiving oxygen therapy
STUDY OBJECTIVES: To elucidate whether a simple walking aid may improve physical performance in COPD patients with chronic respiratory insufficiency who usually carry their own heavy oxygen canister. DESIGN: Randomized crossover trial. SETTING: Physiopathology laboratory of three rehabilitation centers. PATIENTS AND INTERVENTIONS: We studied 60 stable COPD patients (mean age, 70.6 +/- 7.9 years; FEV(1), 44.8 +/- 14.3% of predicted [+/- SD]) with chronic respiratory insufficiency who randomly performed, on 2 consecutive days, a standardized 6-min walking test using two different modalities: a full-weight oxygen canister transported using a small wheeled cart and pulled by the patient (Aid modality) or full-weight oxygen canister carried on the patient's shoulder (No-Aid modality). MEASUREMENTS AND RESULTS: The distance walked, peak effort dyspnea, and leg fatigue scores as primary outcomes, and other cardiorespiratory parameters as secondary outcomes were recorded during both tests. A significant difference (p < 0.05) between the two tests occurred for all the measured outcomes in favor of the Aid modality. Most importantly, significant changes for distance (+ 43 m, p < 0.001), peak effort dyspnea (- 2.0 points, p < 0.001), leg fatigue (- 1.4 points, p < 0.001), as well as for mean and nadir oxygen saturation and heart rate with the Aid modality (but not with the No-Aid modality) were recorded in the subgroup of patients walking < 300 m at baseline. CONCLUSIONS: This study suggests that a simple walking aid may be helpful in COPD patients receiving long-term oxygen therapy, particularly in those with lower residual exercise capacity
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