Search results for "plastic"
showing 10 items of 7296 documents
Magnesium chloride modified with organoaluminium compounds as a support of the zirconocene catalyst for ethylene polymerisation
2004
Abstract This work describes the influence of the modification of the MgCl2(THF)2 and MgCl2 magnesium supports with the AlEt2Cl, MAO, AlEt3, AlMe3, and AlEt2Cl alkylaluminium compounds on heterogenisation of the bis(cyclopentadienyl) zirconium(IV) dichloride Cp2ZrCl2 catalyst. It was found that only the MgCl2(THF)2 support modified with AlEt2Cl gave the heterogeneous catalyst. On the contrary, application of a magnesium carrier modified by AlEt3, AlMe3, and MAO compounds only results in a homogeneous zirconocene catalyst.
Heterogeneous zirconocene catalyst on magnesium support MgCl2(THF)2 modified by AlEt2Cl for ethylene polymerisation
2005
Abstract The heterogeneous bis(cyclopentadienyl)zirconium(IV) dichloride catalyst of the composition MgCl2(THF)/(AlEt2Cl)0.34/(Cp2ZrCl2)0.01 as determined by FTIR, XRD, and AAS analyses was synthesised and, after activation by MAO, applied for ethylene polymerisation. The catalyst turned out to be stable and more active than those magnesium supported catalysts already known from the literature. The polyethylene produced has a relatively high molecular weight (Mw > 200,000 g/mol), a narrow and monomodal molecular weight distribution (MWD = 2.4), a bulk density of about 180 g/dm3, and monomodal particle size distribution. Application of a ternary Al(i-Bu)3/MAO/B(C6F5)3 activator decreased the…
Synthesis of polybutadiene-polycaprolactone multi-blokcs based on hydroxyl telechelic polybutadiene. Composition and kinetic study
2009
International audience
Efficacy of Azacitidine (AZA) in Autoimmune and Inflammatory Disorders (AID) Associated with Myelodysplastic Syndromes (MDS) and Chronic Myelomonocyt…
2015
Abstract Background: AID are seen in 10-30% of MDS and CMML. After initial response to steroids, AID are often poorly controlled and steroid-sparing drugs are difficult to use due to the underlying MDS/CMML. Some case reports suggest a beneficial role of AZA treatment in AID associated to MDS/CMML. Methods: We retrospectively analyzed 22 MDS/CMML patients (pts) with AID who received AZA in French centers between January 2007 and May 2014. Results: Median age of the 22 pts was 70y (range 41-84), including 6F/16M. Diagnosis of MDS/CMML preceded AID (n=8) by a median of 17 months (mo), was concomitant with (n=7) or followed AID (n=7) by a median of 20 mo. 14 pts had lower risk IPSS and 8 highe…
Role of polysialic acid (PSA) in the control of food intake and body weight
2013
Hypothalamus plays a major role in the regulation of energy homeostasis by the presence of neural circuits controlling food intake. These circuits are plastic and can be rewired during adulthood. We hypothesized that synaptic plasticity can occur during physiological conditions. We have shown that synaptic contact on hypothalamic anorexigen POMC neurons are rewired in mouse upon high fat diet (HFD). This synaptic process is mandatory to adjust energy intake and requires the glycan PSA (polysialic acid). PSA promotes synaptic plasticity in the brain by the weakening of cell-to-cell interaction by addition on NCAM (neural cell adhesion molecule). We hypothesized that a defect in brain synapti…
Sintesi chimica di nuovi agenti fotochemioterapici eterociclici, con attività antiproliferativa compresa quella di natura neoplastica
2009
La presente invenzione riguarda la sintesi di nuovi analoghi dell’angelicina, pirrolo[3,2-h]chinolinoni, per la cura di patologie a carattere iperproliferativo comprese quelle di natura neoplastica. La cura si basa sull’azione combinata dei pirrolo[3,2-h]chinolinoni e luce UV-A attraverso una nuova tipologia di fotochemioterapia. Questi nuovi derivati hanno dimostrato interessante fototossicità in vitro nei confronti di cellule tumorali umane ma senza indurre un fotodanno al DNA, il quale rappresenta la principale causa degli effetti collaterali della terapia PUVA.
MRI-visible nanoparticles from hydrophobic gadolinium poly(ε-caprolactone) conjugates
2015
International audience; In this work we report on the synthesis of two hydrophobic and degradable gadolinium poly(ε-caprolactone) conjugates and their use for the preparation of MRI-visible nanoparticles intended for diagnosis applications. Advantage has been taken from functional poly(ε-caprolactone)s (PCL) bearing propargyl (PCL-yne) or amine groups (P(CL-co-NH2VL)) to yield conjugates by following two strategies. In a first approach, an azido-chelate of gadolinium (Gd(III)) has been conjugated by CuAAC to PCL-yne to yield a polymeric chelate containing 2.6 wt% of Gd(III). In a second approach, a dianhydride Gd(III)-ligand was reacted with P(CL-co-NH2VL) to yield, after complexation with …
Extreme statistics in Raman fiber amplifiers : influence of pump depletion and dispersion
2010
OSA 2010 NonLinear Photonics Best Student Poster Award; International audience; We experimentally and theoretically investigate the influence of pump depletion effects on extreme statistics observed in fiber Raman amplifiers. We also report on the impact of the dispersion of the fiber.
Nonlinear optical fiber polarization tracking at 200 krad/s
2011
International audience; We demonstrate endless nonlinear polarization stabilization with a standard telecom fiber at a tracking speed of 200 krads/s. We provide a simple analytical estimate for the response time of nonlinear polarization control
New fiber laser architecture with transform-limited nonlinear spectral compression
2012
International audience; We numerically demonstrate a new fiber laser architecture supporting spectral compression of negatively chirped pulses in passive normally dispersive fiber. Such a process is beneficial for improving the energy efficiency of the cavity as it prevents narrow spectral filtering from being highly dissipative. The proposed laser design provides an elegant way of generating transform-limited picosecond pulses.