312 research outputs found

    Chaotic Interaction of Langmuir Solitons and Long Wavelength Radiation

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    In this work we analyze the interaction of isolated solitary structures and ion-acoustic radiation. If the radiation amplitude is small solitary structures persists, but when the amplitude grows energy transfer towards small spatial scales occurs. We show that transfer is particularly fast when a fixed point of a low dimensional model is destroyed.Comment: LaTex + 4 eps file

    Statistical Mechanics of Unbound Two Dimensional Self-Gravitating Systems

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    We study, using both theory and molecular dynamics simulations, the relaxation dynamics of a microcanonical two dimensional self-gravitating system. After a sufficiently large time, a gravitational cluster of N particles relaxes to the Maxwell-Boltzmann distribution. The time to reach the thermodynamic equilibrium, however, scales with the number of particles. In the thermodynamic limit, N→∞N\to\infty at fixed total mass, equilibrium state is never reached and the system becomes trapped in a non-ergodic stationary state. An analytical theory is presented which allows us to quantitatively described this final stationary state, without any adjustable parameters

    Crystal engineering of coordination polymers and architectures using the [Cu(2,2 '-bipy)](2+) molecular corner as building block (bipy=2,2 '-bipyridyl)

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    The [Cu(2,2'-bipy)](2+) corner unit (1) (2,2'-bipy = 2,2'-bipyridyl), made available by the metathesis of the chlorides in [Cu(2,2'-bipy)Cl-2] with poorly coordinating anions [triflate (1a), BF4- (1b) and NO3- (1c)], has been reacted with a variety of bifunctional ligands, such as 4,4'-bipyridyl (4,4'-bipy), trans-4,4'-azobis(pyridine) (azpy), 1,2-bis(4-pyridyl) ethane (bpetha), trans-1,2-bis(4-pyridyl) ethene (bpethe), 1,3-bis(4-pyridyl) propane (bpp), pyrazine (pyz), i-nicotinate (i-nic) and others. Interesting motifs have been obtained and characterized, including one-dimensional polymeric chains of different kinds, molecular rings and other architectures, depending on the ligand and the counterion. Zig-zag chains exhibiting a variated period have been observed within the species [(1)(4,4'-bipy)(CF3SO3)](CF3SO3) (2a), [(1)(azpy)(H2O)(CF3SO3)](CF3SO3) (3a), [(1)(bpethe)(BF4)](BF4) (2b), [(1)(azpy)(H2O)](NO3)(2)center dot H2O (2c) and [(1)(i-nic)(H2O)](NO3)center dot 2H(2)O (3c). Though the topology of these species is not exceptional, one of them (2c) exhibits a peculiar supramolecular organization of the chains, resulting in warp-and-woof two-dimensional sheets. With the non-rigid ligands bpp and bpetha other motifs can be obtained: the former ligand gives a festoon polymer, [(1)(bpp)(EtOH)](BF4) 2 (3b), while molecular rings are generated with the latter one in the species [(1)(bpetha)(CF3SO3)(2)](2) (4a). Pyrazine with 1a gives dinuclear species that are joined by triflate anions into ladder-like polymers in [{(1)(H2O)(CF3SO3)}(2)(pyz)](CF3SO3)(2) (5a), exhibiting in the crystal structure channels running parallel to the ladders. With the asymmetric ligand 2,4'-bipyridyl (2,4'-bipy) the monomeric species [(1)(2,4'-bipy)(H2O)(BF4)(2)] (4b) is obtained, that forms 1D chains via hydrogen bonds. A different starting species, obtained from [Cu(2,2'-bipy) Cl2] by partial metathesis of the chlorides was also employed: reaction with heptanedinitrile (hdn) gives the derivative [{(1)Cl}(2)(hdn)](BF4)(2) (5b), consisting of chains of dinuclear [(2,2'-bipy) Cu(mu-Cl)(2)Cu(2,2'-bipy)] moieties joined by the bidentate flexible ligand

    Role of OPRM1, clinical and anthropometric variants in neonatal pain reduction

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    An increased awareness on neonatal pain-associated complications has led to the development of pain scales adequate to assess the level of pain experienced by newborns such as the ABC score. A commonly used analgesic procedure is to administer a 33% oral dextrose solution to newborns prior to the painful intervention. Although this procedure is very successful, not in all subjects it reaches complete efficacy. A possible explanation for the different response to the treatment could be genetic variability. We have investigated the genetic variability of the OPRM1 gene in 1077 newborns in relation to non-pharmacologic pain relief treatment. We observed that the procedure was successful in 966 individuals and there was no association between the genotypes and the analgesic efficacy when comparing individuals that had an ABC score = 0 and ABC score >0. However, considering only the individuals with ABC score>0, we found that the homozygous carriers of the G allele of the missense variant SNP rs1799971 (A118G) showed an interesting association with higher ABC score. We also observed that individuals fed with formula milk were more likely to not respond to the analgesic treatment compared to those that had been breastfed

    Are You Happy? A Validation Study of a Tool Measuring Happiness

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    This study aims at evaluating the psychometric properties of a new scale to measure experienced happiness-the Measure of Happiness (MH)-in a nonclinical sample composed of Italian adults from the general population. The MH was developed not only to provide a global measure of happiness, but also and more importantly to identify the specific areas of the individual's life that are related to the experienced happiness. A total of 787 adults filled the MH and other self-report questionnaires, in order to assess the factor structure, reliability and external validity of the measure. The factorial analysis identified the following five dimensions: Psychophysics Status, Financial Status, Relational Private Sphere, Socio-Relational Sphere, and Life Perspective. The scale so defined was administered to a second independent group of 421 participants for the (multigroup) confirmatory factor analysis (CFA). A multigroup factor analysis based on gender confirmed the MH structure. The convergent validity of the MH was assessed by comparing the MH scores with a previously validated test of happiness and quality of life, as well as with dispositional constructs with which happiness is known to be negatively correlated, namely, anxiety and depression. The MH showed satisfactory psychometric properties and a strong significant positive relationship between the two measures of happiness, and a substantial negative association with the measures of anxiety and depression, supporting the validity of the MH to assess the construct of experienced happiness. The implications and possible applications of the MH are then discussed

    Synthesis, in vitro activity and in vivo toxicity of the new 2,3-dinitrobutadiene derivative (1E,3E)-1,4-bis(2-naphthyl)-2,3-dinitro-1,3-butadiene

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    Abstract Our interesting results on the antiproliferative (in vitro) and antitumour (in vivo) activities of (1E,3E)-1,4-bis(1-naphthyl)-2,3-dinitro-1,3-butadiene (1-Naph-DNB) have more recently induced us to design and synthesize some new 1,4-diaryl-2,3-dinitro-1,3-butadienes characterized by a common arylnitrobutadiene array but with different geometric and/or functional properties. This task was undertaken with the aim to obtain new compounds with an enhanced antiproliferative activity and, possibly, a different specificity with respect to the original (lead) compound. (1E,3E)-1,4-Bis(2-naphthyl)-2,3-dinitro-1,3-butadiene (2-Naph-DNB) is one of the molecules so obtained, a structural isomer of 1-Naph-DNB provided with a different spatial arrangement. When analyzed in vitro for its inhibition of cell proliferation 2-Naph-DNB showed a remarkable activity in the range of micromolar concentrations, with significant differences, with respect to 1-Naph-DNB, against some cell lines. Furthermore, it was able to significantly trigger apoptosis, to up-regulate p53, to block cells in the G2/M phase of the cell cycle and, finally, to slightly bind to DNA forming interstrand cross-links (ISCL). 2-Naph-DNB was then analyzed for its toxic activity in vivo in CD1 mice. This allowed the determination of toxicity parameters such as the lethal doses (LD) and the maximal tolerated dose (MTD) together with the definition of the spectrum of tissue alterations due to its administration i.v. Altogether our data suggest that the idea of modifying the geometry of the lead compound 1-Naph-DNB deserves further investigation aimed at synthesizing new molecules with similar chemical functionalities but with different spatial requirements, hopefully characterized by still enhanced activities in terms of inhibition of cell proliferation and apoptosis

    Utility of neutrophil-to-lymphocyte ratio to identify long-term survivors among HCC patients treated with sorafenib

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    Sorafenib is the first multikinase inhibitor demonstrating a survival benefit for patients suffering from advanced hepatocellular carcinoma (HCC). However, 1 issue remains open: what is the factor able to predict which patients will be long survivors?In the present study, we harnessed the potential of conditional survival, aiming at estimating the probability that a patient receiving sorafenib survives for more than 3 years.The present multicentric study was conducted on a cohort of 438 HCC patients. The primary end point was conditional overall survival. Kaplan-Meier survival analysis was used to calculate conditional overall survival probabilities at 3 years.The 3-year conditional survival of patients without disease progression highlights that NLR and ECOG are the factors that most accurately predict the probability of long survival. The 3-year conditional survival of patients with disease progression showed a medium effect size for HCV status, alpha-fetoprotein and NLR at all time-points. Macro-vascular portal vein invasion, extra hepatic disease, and BCLC we have a large effect size at 6 months and a medium effect size at 12 and 24 months.Our findings support the use of baseline NLR for the identification of patients with a higher probability of long-survival. NLR should be used as a stratification factor in the forthcoming clinical trials on the drugs for the advanced HCC now in pipeline

    Definition of the Prognostic Role of MGMT Promoter Methylation Value by Pyrosequencing in Newly Diagnosed IDH Wild‐Type Glioblastoma Patients Treated with Radiochemotherapy: A Large Multicenter Study

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    Background. O6‐methylguanine (O6‐MeG)‐DNA methyltransferase (MGMT) methylation status is a predictive factor for alkylating treatment efficacy in glioblastoma patients, but its prognostic role is still unclear. We performed a large, multicenter study to evaluate the association between MGMT methylation value and survival. Methods. We evaluated glioblastoma patients with an assessment of MGMT methylation status by pyrosequencing from nine Italian centers. The inclusion criteria were histological diagnosis of IDH wild‐type glioblastoma, Eastern Cooperative Oncology Group Performance Status (ECOG‐PS) ≀2, and radio‐chemotherapy treatment with temozolomide. The relationship between OS and MGMT was investigated with a time‐dependent Receiver Operating Characteristics (ROC) curve and Cox regression models. Results. In total, 591 newly diagnosed glioblastoma patients were analyzed. The median OS was 16.2 months. The ROC analysis suggested a cut‐off of 15% for MGMT methylation. The 2‐year Overall Survival (OS) was 18.3% and 51.8% for MGMT methylation <15% and ≄15% (p < 0.0001). In the multivariable analysis, MGMT methylation <15% was associated with impaired survival (p <0.00001). However, we also found a non‐linear association between MGMT methylation and OS (p = 0.002): median OS was 14.8 months for MGMT in 0–4%, 18.9 months for MGMT in 4–40%, and 29.9 months for MGMT in 40– 100%. Conclusions. Our findings suggested a non‐linear relationship between OS and MGMT promoter methylation, which implies a varying magnitude of prognostic effect across values of MGMT promoter methylation by pyrosequencing in newly diagnosed IDH wild‐type glioblastoma patients treated with chemoradiotherapy
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