Rheological Properties of Very High-Strength Portland Cement Pastes: Influence of Very Effective Superplasticizers

The influence of the addition of very effective superplasticizers, that are commercially available, employed for maximising the solid loading of very high-strength Portland cement pastes, has been investigated. Cement pastes were prepared from deionized water and a commercially manufactured Portland cement (Ultracem 52.5 R). Cement and water were mixed with a vane stirrer according to ASTM Standard C305. The 0.38 to 0.44 water/cement ratio range was investigated. Three commercial superplasticizing agents produced by Ruredil S.p.a. were used. They are based on a melamine resin (Fluiment 33 M), on a modified lignosulphonate (Concretan 200 L), and on a modified polyacrylate (Ergomix 1000). Rheological tests were performed at 25°C by using the rate controlled coaxial cylinder viscometer Rotovisko-Haake 20, system M5-osc., measuring device MV2P with serrated surfaces. The tests were carried out under continuous flow conditions. The results of this study were compared with those obtained in a previous article for an ordinary Portland cement paste

Different patterns of cortical excitability in major depression and vascular depression: a transcranial magnetic stimulation study

BACKGROUND: Clinical and functional studies consider major depression (MD) and vascular depression (VD) as different neurobiological processes. Hypoexcitability of the left frontal cortex to transcranial magnetic stimulation (TMS) is frequently reported in MD, whereas little is known about the effects of TMS in VD. Thus, we aimed to assess and compare motor cortex excitability in patients with VD and MD. METHODS: Eleven VD patients, 11 recurrent drug-resistant MD patients, and 11 healthy controls underwent clinical, neuropsychological and neuroimaging evaluations in addition to bilateral resting motor threshold, cortical silent period, and paired-pulse TMS curves of intracortical excitability. All patients continued on psychotropic drugs, which were unchanged throughout the study. RESULTS: Scores on one of the tests evaluating frontal lobe abilities (Stroop Color-Word interference test) were worse in patients compared with controls. The resting motor threshold in patients with MD was significantly higher in the left hemisphere compared with the right (p < 0.05), and compared with the VD patients and controls. The cortical silent period was bilaterally prolonged in MD patients compared with VD patients and controls, with a statistically significant difference in the left hemisphere (p < 0.01). No differences were observed in the paired-pulse curves between patients and controls. CONCLUSIONS: This study showed distinctive patterns of motor cortex excitability between late-onset depression with subcortical vascular disease and early-onset recurrent drug resistant MD. The data provide a TMS model of the different processes underlying VD and MD. Additionally, our results support the “Vascular depression hypothesis” at the neurophysiological level, and confirm the inter-hemispheric asymmetry to TMS in patients with MD. We were unable to support previous findings of impaired intracortical inhibitory mechanisms to TMS in patients with MD, although a drug-induced effect on our results cannot be excluded. This study may aid the understanding of the pathogenetic differences underlying the clinical spectrum of depressive disorders

Investigation of 2 (Docosylamino)-5-nitropyridine monolayers and Langmuir-Blodgett films

The behavior of 2-(docosylamino)-5-nitropyridine (DCANP) spreading monolayers was investigated as a function of temperature, pH, and subphase composition. The interactions of DCANP monolayers with copper ions dissolved into the subphase at different concentrations were also studied. The investigations were carried out by measuring surface pressure and surface potential−area isotherms. Langmuir−Blodgett (LB) films transferred from pure water and copper aqueous subphases were also studied by Fourier transform infrared (FTIR), UV−vis, and electron paramagnetic resonance (EPR) spectroscopies, X-ray photoelectron spectroscopy (XPS), ellipsometry, and refractive index measurements. The interactions between copper ions and DCANP molecules were investigated by means of various techniques in the bulk phase, in monolayers, and in LB films. Clear evidence of interactions between DCANP and copper ions was provided only from EPR spectroscopy in the LB films, because of the very small molar ratio of bound/free DCANP in the LB films. The refractive index of Cu-doped LB films was shown to be increased by the presence of metal ions

Molecular Weight Induced Order in poly-3BCMU spun films

Poly-3-butoxycarbonylmethylurethane (poly-3BCMU) spun films were formed from polymer batches with different molecular weight (from about 100,000 to 375,000 g/mol). The two-photon absorption (TPA) spectrum of poly-3BCMU films was measured in the near infrared from 800 to 1350 nm by using femtosecond pulses. Although the TPA spectrum features were the same in all investigated films, the TPA coefficient β was two times larger in the films obtained from the higher molecular weight batches. As the number of repeat units in all polymer batches was well above the saturation limit of the hyperpolarisability γ in conjugated chains, the observed behaviour can be explained with the assumption that a more ordered and planar arrangement of the polymer chains is promoted in the polymer films with higher molecular weight. This hypothesis is confirmed by the measurement of the film refractive index and birefringence

Analysis with the Africa Grid Science Gateway of ALICE Data from the ALICE Collaboration - LHC2010b_pp_ESD_117222

This is the software of a JSR 286 compliant "portlet" installed on the <a href="http://sgw.africa-grid.org" target="_blank">Africa Grid Science Gateway</a> that allows the analysis of the dataset mentioned in the title. Click on the External link below to be automatically re-directed to the execution page of the portlet on the Science Gateway