717 research outputs found
Polyvinylpyridine-supported palladium nanoparticles: An efficient catalyst for Suzuki–Miyaura coupling reactions
Palladium nanoparticles (Pd NPs) synthesized by the metal vapor synthesis technique were supported on poly(4-vinylpyridine) 2% cross-linked with divinylbenzene (Pd/PVPy). Transmission electron microscopy revealed the presence of small metal nanoparticles (dm = 2.9 nm) highly dispersed on the PVPy. The Pd/PVPy system showed high catalytic efficiency in Suzuki-Miyaura carbon–carbon coupling reactions of both non-activated and deactivated aromatic iodides and bromides with aryl boronic acids, carried out under an air atmosphere. The high turnover of the catalyst and the ability of the PVPy resin to retain active Pd species are highlighted. By comparing the catalytic performances of Pd/PVPy with those observed by using commercially available Pd-based supported catalysts, the reported system showed higher selectivity and lower Pd leaching
Identification and synthesis of new sex-specific components of olive fruit fly (Bactrocera oleae) female rectal gland, through original Negishi reactions on supported catalysts
In the present study, eleven new sex-specific components extracted from female rectal gland of olive fruit flies were synthesized and identified. The quantitative determination of those components by GC and GC/EI-MS, at different moments of the insect life span, highlighted the growing trend of their secretion. While for the synthesis of saturated esters, conventional transesterification methods could be adopted, for the synthesis of unsaturated components, a Negishi cross-coupling between organozinc halides and (Z)-1-bromo-1-alkenes was developed. To the extent of our knowledge, this reaction represents the first example of supported-catalyst promoted Negishi coupling, between an alkylzinc reagent and an alkenyl halide
Turnover of Galactans and Other Cell Wall Polysaccharides during Development of Flax Plants
Total Synthesis of Asparenydiol by Two Sonogashira Cross-Coupling Reactions Promoted by Supported Pd and Cu Catalysts
Asparenydiol, which is an important natural compound with potential pharmacological activities, was synthesized through two Sonogashira cross-coupling reactions catalyzed by supported Pd and Cu catalysts and by a Mitsunobu etherification. The optimization of the Sonogashira couplings allowed the use of catalysts supported on different matrices with good results in terms of catalytic efficiency and yields
Prevalence study of mental disorders in an Italian region. Preliminary report
Background Mental disorders are a major public health problem. However, over the last few years, there have been few studies aimed at evaluating their diffusion. Therefore, this study aimed at evaluating: the prevalence of the most frequent psychiatric disorders in the general population residing in Tuscany using a clinical scale administered by trainee in psychiatry. Methods The study was carried out on a representative sample of the general population aged > 18 years, randomly extracted from the register of patients in the Tuscany region, adopting a proportional sampling method stratified by gender, age group and Local Health Units (LHU). Each person was contacted by letter followed by a phone call from an operator who makes an appointment with the trainee in psychiatry. The diagnostic interview conducted was the Mini-International Neuropsychiatric Interview (MINI). Point and lifetime prevalence by gender and age group were calculated. Differences and associations were considered statistically significant if their p-values were less than 0.05. Results Of the 408 people involved, 390 people were enrolled (of which 52.6% female). The 28.5% of the sample had been affected by a psychiatric disorder during their lifetime. In their lifetime, the most represented psychiatric disorders were major depressive episode (20.4%), major depressive disorder (17.0%) and panic disorder (10.3%), more frequent in the female than the male group. Current conditions were predominantly major depressive episode (3.1%) and agoraphobia (2.8%). A 5.9% rate of current suicidal ideation was also found. Conclusions In the general population, 28.5% of people reported a psychiatric disorder during their lifetime. This prevalence is considerably higher than that reported in a previous study carried out in central Italy
MAGY: an innovative high voltage - low current power supply for gyrotron
From the electrical point of view, the body and the anode of high power gyrotrons behave as capacitive loads. A highly dynamic power supply is, therefore, hard to achieve. The MAGY concept (Modulator for the Anode of a triode type GYrotron) embodies an innovative solution to manage the capacitive current ensuring a very low ripple on the output voltage. It consists of a series of independent, bi-directional and regulated DC sources. Compared to existing topologies, this solution requires a smaller number of power modules. It avoids internal high frequency modulation and simultaneously offers high resolution of the output voltage and a wide range of operating scenarios. (C) 2011 Elsevier B.V. All rights reserved
Hypoglycemic activity of polysaccharide fractions containing Ăź-glucans from extracts of Rhynchelytrum repens (Willd.) C.E. Hubb., Poaceae
Mood symptoms and suicidality across the autism spectrum
Abstract Background Autism spectrum is a psychopathological dimension which encompasses a wide range of clinical presentations: from subthreshold forms and autistic traits (AT), that can be found in the general population, to full-blown autism spectrum disorder (ASD). Many studies reported high rates of comorbidity between both ASD and AT and mood disorders, as well as a high prevalence of suicidal ideation among patients with ASD/AT. The aim of this study was to investigate the presence of mood symptoms and suicidal ideation and behaviors in patients with full-blown ASD and in subjects with AT, as well in a healthy control (HC) group, with a specific focus on which of the autistic features may be predictive of suicidal ideation and behaviors. Methods We recruited 262 adult subjects: 34 with ASD without intellectual impairment or language disability (ASD group), 68 fulfilling only one symptom criterion for ASD according to DSM-5 but who do not meet criteria for a full-blown diagnosis of ASD (AT group), and 160 HC. All subjects were assessed with the Structured Clinical Interview for DSM-5 (SCID-5); in addition, they were asked to fill two questionnaires: The Mood Spectrum, Self-report (MOODS-SR) and the Adult Autism Subthreshold Spectrum (AdAS Spectrum). Results ASD subjects reported significantly higher AdAS Spectrum and MOODS-SR total scores, as well as higher MOODS-SR depressive component total scores, when compared with AT and HC subjects. AT subjects scored significantly higher than the HC group. No significant differences were reported between ASD and AT subjects for the suicidality score according to MOODS-SR, despite both groups scored significantly higher than the HC group. The strongest predictor of suicidality score were MOODS-SR depressive component score and AdAS Spectrum Restricted interests and rumination domain score. Conclusions Our results highlight a correlation between autism and mood spectrum, as well as between suicidality and both ASD and AT. Subthreshold forms of ASD should be accurately investigated due to their relationship with suicidal thoughts and behaviors
Reduction in benefits of total flux expansion on divertor detachment due to parallel flows
The Super-X divertor (SXD) is an alternative divertor configuration
leveraging total flux expansion at the outer strike point (OSP). Key features
for the attractiveness of the SXD are facilitated detachment access and
control, as predicted by the extended 2-point model (2PM). However, parallel
flows are not consistently included in the 2PM. In this work, the 2PM is
refined to overcome this limitation: the role of total flux expansion on the
pressure balance is made explicit, by including the effect of parallel flows.
In consequence, the effect of total flux expansion on detachment access and
control is weakened, compared to predictions of the 2PM. This new model
partially explains discrepancies between the 2PM and experiments performed on
TCV, in ohmic L-mode scenarios, where in core density ramps in lower
single-null (SN) configuration, the impact of the OSP major radius Rt on the
CIII emission front movement in the divertor outer leg - used as a proxy for
the plasma temperature - is substantially weaker than 2PM predictions; and in
OSP sweeps in lower and upper SN configurations, with a constant core density,
the peak parallel particle flux density at the OSP is almost independent of Rt,
while the 2PM predicts a linear dependence. Finally, analytical and numerical
modelling of parallel flows in the divertor is presented, to support the
argument. It is shown that an increase in total flux expansion can favour
supersonic flows at the OSP. Parallel flows are also shown to be relevant by
analysing SOLPS-ITER simulations of TCV
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