599 research outputs found

    Relaxation times of kinetically constrained spin models with glassy dynamics

    Full text link
    We analyze the density and size dependence of the relaxation time τ\tau for kinetically constrained spin systems. These have been proposed as models for strong or fragile glasses and for systems undergoing jamming transitions. For the one (FA1f) or two (FA2f) spin facilitated Fredrickson-Andersen model at any density ρ<1\rho<1 and for the Knight model below the critical density at which the glass transition occurs, we show that the persistence and the spin-spin time auto-correlation functions decay exponentially. This excludes the stretched exponential relaxation which was derived by numerical simulations. For FA2f in d≄2d\geq 2, we also prove a super-Arrhenius scaling of the form exp⁥(1/(1−ρ))≀τ≀exp⁥(1/(1−ρ)2)\exp(1/(1-\rho))\leq \tau\leq\exp(1/(1-\rho)^2). For FA1f in dd=1,21,2 we rigorously prove the power law scalings recently derived in \cite{JMS} while in d≄3d\geq 3 we obtain upper and lower bounds consistent with findings therein. Our results are based on a novel multi-scale approach which allows to analyze τ\tau in presence of kinetic constraints and to connect time-scales and dynamical heterogeneities. The techniques are flexible enough to allow a variety of constraints and can also be applied to conservative stochastic lattice gases in presence of kinetic constraints.Comment: 4 page

    Dextran-curcumin nanoparticles as a methotrexate delivery vehicle: A step forward in breast cancer combination therapy

    Get PDF
    With the aim to effectively deliver methotrexate (MTX) to breast cancer cells, we designed a nanocarrier system (DC) derived from the self-assembly of a dextran-curcumin conjugate prepared via enzyme chemistry with immobilized laccase acting as a solid biocatalyst. Nanoparticles consisted of homogeneously dispersed nanospheres with a mean diameter of 290 nm, as characterized by combined transmission electron microscopy and dynamic light scattering investigations. DC was able to control the MTX release overtime (t1/2 value of 310 min), with cell internalization studies proving its presence inside MCF-7 cytoplasm. Finally, improved MTX efficacy was obtained in viability assays, and attributed to the synergy of curcumin moieties and loaded MTX as underlined by a combination index (CI) < 1

    Reasons why HIV-positive women do not want to have a child: the questionnaire-based DIDI study

    Get PDF
    Given that the majority of HIV‐positive women are of reproductive age, it is necessary to understand the interaction between HIV and family planning, especially as antiretroviral medications allow to live longer, healthier lives. Aim of this analysis form the DIDI study was to assess prevalence of motherhood desire in current years and to identify variables associated pregnancy decision‐making in HIV‐infected women. DIDI is an Italian, 16‐center, questionnaire‐based survey performed in 585 HIV‐positive women between Nov. 2010 and Feb. 2011. The items covered in the self‐administered questionnaire included: socio‐demographic characteristics, sexual and gynecological health, motherhood desire, strategies adopted to become pregnant, reasons for not wanting a child, partnership, HIV disclosure, physical and mental health, ART adherence, drug use. For the present analysis only women aged<45 years and engaged in a partnership were included. Absence of motherhood desire was defined by a negative answer at the question whether the women at present would like to have a child. 178 women were included: mean age 39 (IQR, 33–42), HIV transmission heterosexual 75%, IVDU 11%, heterosexual/IVDU 2.5%, not known 7.5%; mean CD4 and HIV‐RNA were 552/mmc (+252) and 3.85 c/ml (+4.7), respectively. Absence of motherhood desire was found in 61% of women; 50% of women declared that HIV negatively affected motherhood desire, and 22% declared a decrease in desire after start of ART. The probability of vertical transmission was estimated higher than 50% by 19% of women, even when adopting all preventive measures. Not wanting a child was associated with: fear of vertical transmission (p<0.001), fear of not being able to raise the child (p<0.001), decline in motherhood desire after HIV (p=0.007), unstable partnership (p=0.02). At multivariable analysis, variables found to be significantly associated with negative pregnancy decision‐making were: fear of vertical transmission (AOR 3.75; 95%CI 1.18–11.89), economic restrictions (AOR 0.28; 95% CI 0.10–0.76 In conclusion, absent motherhood desire in HIV‐positive women with child‐bearing potential is frequent and essential information on vertical HIV transmission is lacking. HIV‐positive women of childbearing age may benefit from counseling interventions sensitive to factors that influence infected women's pregnancy decisions

    On the aggregation and nucleation mechanism of the monoclonal antibody anti-CD20 near liquid-liquid phase separation (LLPS)

    Get PDF
    The crystallization of Anti-CD20, a full-length monoclonal antibody, has been studied in the PEG400/Na2SO4/Water system near Liquid-Liquid Phase Separation (LLPS) conditions by both sitting-drop vapour diffusion and batch methods. In order to understand the Anti-CD20 crystallization propensity in the solvent system of different compositions, we investigated some measurable parameters, normally used to assess protein conformational and colloidal stability in solution, with the aim to understand the aggregation mechanism of this complex biomacromolecule. We propose that under crystallization conditions a minor population of specifically aggregated protein molecules are present. While this minor species hardly contributes to the measured average solution behaviour, it induces and promotes crystal formation. The existence of this minor species is the result of the LLPS occurring concomitantly under crystallization conditions

    Novel ester and acid derivatives of the 1,5-diarylpyrrole scaffold as anti-inflammatory and analgesic agents. Synthesis and in vitro and in vivo biological evaluation.

    Get PDF
    A new generation of selective cyclooxygenase-2 (COX-2) inhibitors (coxibs) was developed to circumvent the major side effects of cyclooxygenase-1 (COX-1) and COX-2 inhibitors (stomach ulceration and nephrotoxicity). As a consequence, coxibs are extremely valuable in treating acute and chronic inflammatory conditions. However, the use of coxibs, such as rofecoxib (Vioxx), was discontinued because of the high risk of cardiovascular adverse events. More recent clinical findings highlighted how the cardiovascular toxicity of coxibs could be mitigated by an appropriate COX-1 versus COX-2 selectivity. We previously reported a set of substituted 1,5-diarylpyrrole derivatives, selective for COX-2. Here, we describe the synthesis of new 1,5-diarylpyrroles along with their inhibitory effects in vitro, ex vivo, and in vivo toward COX isoenzymes and their analgesic activity. Isopropyl-2-methyl-5-[4-(methylsulfonyl)phenyl]-1-phenyl-1H-pyrrole-3-acetate (10a), a representative member of the series, was selected for pharmacokinetic and metabolic studies

    Pressure-energy correlations in liquids. I. Results from computer simulations

    Get PDF
    We show that a number of model liquids at fixed volume exhibit strong correlations between equilibrium fluctuations of the configurational parts of (instantaneous) pressure and energy. We present detailed results for thirteen systems, showing in which systems these correlations are significant. These include Lennard-Jones liquids (both single- and two-component) and several other simple liquids, but not hydrogen-bonding liquids like methanol and water, nor the Dzugutov liquid which has significant contributions to pressure at the second nearest neighbor distance. The pressure-energy correlations, which for the Lennard-Jones case are shown to also be present in the crystal and glass phases, reflect an effective inverse power-law potential dominating fluctuations, even at zero and slightly negative pressure. An exception to the inverse-power law explanation is a liquid with hard-sphere repulsion and a square-well attractive part, where a strong correlation is observed, but only after time-averaging. The companion paper [arXiv:0807.0551] gives a thorough analysis of the correlations, with a focus on the Lennard-Jones liquid, and a discussion of some experimental and theoretical consequences.Comment: Some changes corresponding to those made in proof of the accepted articl

    Pressure-energy correlations in liquids. II. Analysis and consequences

    Get PDF
    We present an analysis and discuss consequences of the strong correlations of the configurational parts of pressure and energy in their equilibrium fluctuations at fixed volume reported for simulations of several liquids in the companion paper [arXiv:0807.0550]. The analysis concentrates specifically on the single-component Lennard-Jones system. We demonstrate that the potential may be replaced, at fixed volume, by an effective power-law, but not because only short distance encounters dominate the fluctuations. Indeed, contributions to the fluctuations are associated with the whole first peak of the RDF, as we demonstrate by an analysis of the spatially resolved covariance matrix. The reason the effective power-law works so well depends on going beyond single-pair effects and on the constraint of fixed volume. In particular, a better approximation to the potential includes a linear term, which contributes to the mean values of potential energy and virial, but not to their fluctuations. We also study the T=0 limit of the crystalline phase, where the correlation coefficient becomes very close, but not equal, to unity. We then consider four consequences of strong pressure-energy correlations: (1) analyzing experimental data for supercritical Ar we find 96% correlation; (2) we discuss the significance acquired by the correlations for viscous van der Waals liquids approaching the glass transition: For strongly correlating viscous liquids knowledge of just one of the eight frequency-dependent thermoviscoelastic response functions basically implies knowledge of them all; (3) we re-interpret aging simulations of ortho-terphenyl carried out by Mossa {\it et al.} in 2002, showing their conclusions follow from the strongly correlating property; and (4) we discuss correlations in model biomembranes.Comment: Some changes corresponding to those made in the proof of the accepted articl

    Non-hormonal treatment of vulvo-vaginal atrophy-related symptoms in post-menopausal women

    Get PDF
    In post-menopausal period vulvo-vaginal atrophy (VVA)-related symptoms may seriously affect women's quality of life. Hormonal replacement therapy effectively relieves these symptoms but it is not always safe or accepted, and a non-hormonal treatment is often needed instead. Over a period of 12 weeks, we tested the effect of a twice-a-week vulvo-vaginal application of a hyaluronic acid, AC collagen, isoflavones and vitamins-based cream (Perilei Pausa(Âź)) on 35 women in post-menopausal period, reporting VVA-related symptoms. After 12 weeks of treatment with Perilei Pausa(Âź) a significant improvement in vaginal dryness, vulvo-vaginal itching, dyspareunia (P < 0.001), dysuria (P = 0.02), nocturia (P = 0.009) and pollakiuria (P = 0.005) was reported by the women. Colposcopical score assessing the intensity of atrophic colpitis, cervico-vaginal paleness and petechiae was also reduced (P = 0.037, P = 0.016 and P = 0.032, respectively). No significant difference in terms of maturation value of cervico-vaginal epithelium was observed. In conclusion, Perilei Pausa(Âź) may represent an effective and safe alternative treatment of symptomatic VVA in post-menopausal women

    Molecular and Functional Characterization of Three Different Postzygotic Mutations in PIK3CA-Related Overgrowth Spectrum (PROS) Patients: Effects on PI3K/AKT/mTOR Signaling and Sensitivity to PIK3 Inhibitors

    Get PDF
    BACKGROUND PIK3CA-related overgrowth spectrum (PROS) include a group of disorders that affect only the terminal portion of a limb, such as type I macrodactyly, and conditions like fibroadipose overgrowth (FAO), megalencephaly-capillary malformation (MCAP) syndrome, congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome and Hemihyperplasia Multiple Lipomatosis (HHML). Heterozygous postzygotic PIK3CA mutations are frequently identified in these syndromes, while timing and tissue specificity of the mutational event are likely responsible for the extreme phenotypic variability observed. METHODS: We carried out a combination of Sanger sequencing and targeted deep sequencing of genes involved in the PI3K/AKT/mTOR pathway in three patients (1 MCAP and 2 FAO) to identify causative mutations, and performed immunoblot analyses to assay the phosphorylation status of AKT and P70S6K in affected dermal fibroblasts. In addition, we evaluated their ability to grow in the absence of serum and their response to the PI3K inhibitors wortmannin and LY294002 in vitro. RESULTS AND CONCLUSION: Our data indicate that patients' cells showed constitutive activation of the PI3K/Akt pathway. Of note, PI3K pharmacological blockade resulted in a significant reduction of the proliferation rate in culture, suggesting that inhibition of PI3K might prove beneficial in future therapies for PROS patients

    Role of Low-Molecular-Weight Heparin in Hospitalized Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Pneumonia: A Prospective Observational Study

    Get PDF
    Background: This study was conducted to evaluate the impact of low-molecular-weight heparin (LMWH) on the outcome of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. Methods: This is a prospective observational study including consecutive patients with laboratory-confirmed SARS-CoV-2 pneumonia admitted to the University Hospital of Pisa (March 4-April 30, 2020). Demographic, clinical, and outcome data were collected. The primary endpoint was 30-day mortality. The secondary endpoint was a composite of death or severe acute respiratory distress syndrome (ARDS). Low-molecular-weight heparin, hydroxychloroquine, doxycycline, macrolides, antiretrovirals, remdesivir, baricitinib, tocilizumab, and steroids were evaluated as treatment exposures of interest. First, a Cox regression analysis, in which treatments were introduced as time-dependent variables, was performed to evaluate the association of exposures and outcomes. Then, a time-dependent propensity score (PS) was calculated and a PS matching was performed for each treatment variable. Results: Among 315 patients with SARS-CoV-2 pneumonia, 70 (22.2%) died during hospital stay. The composite endpoint was achieved by 114 (36.2%) patients. Overall, 244 (77.5%) patients received LMWH, 238 (75.5%) received hydroxychloroquine, 201 (63.8%) received proteases inhibitors, 150 (47.6%) received doxycycline, 141 (44.8%) received steroids, 42 (13.3%) received macrolides, 40 (12.7%) received baricitinib, 13 (4.1%) received tocilizumab, and 13 (4.1%) received remdesivir. At multivariate analysis, LMWH was associated with a reduced risk of 30-day mortality (hazard ratio [HR], 0.36; 95% confidence interval [CI], 0.21-0.6; P &lt;.001) and composite endpoint (HR, 0.61; 95% CI, 0.39-0.95; P =.029). The PS-matched cohort of 55 couples confirmed the same results for both primary and secondary endpoint. Conclusions: This study suggests that LMWH might reduce the risk of in-hospital mortality and severe ARDS in coronavirus disease 2019. Randomized controlled trials are warranted to confirm these preliminary findings
    • 

    corecore