Aerocellulose based on all-cellulose composites Duchemin, Benoît J.C; Staiger, Mark P; Tucker, Nick ...
Journal of applied polymer science,
5 January 2010, Letnik:
115, Številka:
1
Journal Article
Recenzirano
Novel aerogels (or aerocellulose) based on all-cellulose composites were prepared by partially dissolving microcrystalline cellulose (MCC) in an 8 wt % LiCl/DMAc solution. During this process, large ...MCC crystals and fiber fragments were progressively split into thinner crystals and cellulose fibrils. The extent of the transformation was controlled by using cellulose concentrations ranging from 5 to 20 wt % in the LiCl/DMAc solution. Cellulose gels were precipitated and then processed by freeze-drying to maintain the openness of the structure. The density of aerocellulose increased with the initial cellulose concentration and ranged from 116 up to 350 kg m⁻³. Aerocellulose with relatively high mechanical properties were successfully produced. The flexural strength of the materials reached 8.1 MPa and their stiffness was as high as 280 MPa.
The irradiation of a thorium target by light charged particles (protons and deuterons) leads to the production of several isotopes of medical interest. Direct nuclear reaction allows the production ...of Protactinium-230 which decays to Uranium-230 the mother nucleus of Thorium-226, a promising isotope for alpha radionuclide therapy. The fission of Thorium-232 produces fragments of interest like Molybdenum-99, Iodine-131 and Cadmium-115g. We focus our study on the production of these isotopes, performing new cross section measurements and calculating production yields. Our new sets of data are compared with the literature and the last version of the TALYS code.
Several terbium isotopes are suited for diagnosis or therapy in nuclear medicine. Tb-155 is of interest for SPECT imaging and/or Auger therapy. High radionuclide purity is mandatory for many ...applications in medicine. The quantification of the activity of the produced contaminants is therefore as important as that of the radionuclide of interest. The experiments performed at the ARRONAX cyclotron (Nantes, France), using the deuteron beam delivered up to 34MeV, provide an additional measurement of the excitation function of the Gd-nat(d,x)Tb-155 reaction and of the produced terbium and gadolinium contaminants. In this study, we investigate the achievable yield for each radionuclide produced in natural gadolinium as a function of the deuteron energy. Other reactions are discussed in order to define the production route that could provide Tb-155 with a high yield and a high radionuclide purity. This article aims to improve data for the Gd-nat(d,x) reaction and to optimize the irradiation conditions required to produce Tb-155.
•The medical interest of terbium-155.•Deuteron induced reactions on natural gadolinium up to 34MeV.•Excitation functions measured with the stacked-foil technique.•Comparison with the TALYS code version 1.6.•Tb-155 achievable yield and radionuclide purity.
New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The ...experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x)
Access to reliable exposure data is essential to evaluate the toxicological safety of ingredients in cosmetic products. This study was carried out by European cosmetic manufacturers acting within the ...trade association Colipa, with the aim to construct a probabilistic European population model of exposure. The study updates, in distribution form, the current exposure data on daily quantities of six cosmetic products. Data were collected using a combination of market information databases and a controlled product use study. In total 44,100 households and 18,057 individual consumers in five European countries provided data using their own products. All product use occasions were recorded, including those outside of home. The raw data were analysed using Monte Carlo simulation and a European Statistical Population Model of exposure was constructed. A significant finding was an inverse correlation between frequency of product use and quantity used per application for body lotion, facial moisturiser, toothpaste and shampoo. Thus it is not appropriate to calculate daily exposure to these products by multiplying the maximum frequency value by the maximum quantity per event value. The results largely confirm the exposure parameters currently used by the cosmetic industry. Design of this study could serve as a model for future assessments of population exposure to chemicals in products other than cosmetics.
BackgroundData on the effects of vedolizumab on joint manifestations remain controversial.1,2 ObjectivesThe purpose of this study was to1 evaluate baseline characteristics of crohn’s disease (CD) and ...ulcerative colitis (UC) patients treated with vedolizumab,2 assess the effect of vedolizumab on joint manifestations in patients with inflammatory bowel disease (IBD)-associated Spondyloarthritis (SpA), and3 evaluate new onset of SpA under VDZ.MethodsThis single-centre, retrospective and observational study was conducted from July 2014 to July 2017. The charts of all patients with IBD who had undergone treatment with vedolizumab for more than 3 months were reviewed. The patients’ demographic and clinical characteristics were collected. Data on IBD-associated SpA were collected as well as new onset of SpA under VDZ. The ASAS criteria were used to establish the diagnosis of SpA.ResultsPatient characteristics and main results are shown in table 1. A total of 171 patients diagnosed with IBD were treated with vedolizumab from July 2014 to July 2017. Notably, 97.1% of patients had been previously treated with at least one TNF-α inhibitor. All patients included in this study completed the induction phase at last observation, and the mean follow-up of the entire cohort was 14.3±12.0 months. Ten (5.8%) patients had a history of IBD-associated SpA but were in clinical remission at the time of initiation of VDZ, whereas 4 (2.4%) had active SpA when VDZ was started. First, no clinical benefit on SpA following initiation of VDZ was found in those 4 patients with active SpA. Second, exacerbation of SpA in patients with clinical remission at initiation of VDZ was found in 6/10 patients whereas no effect was reported in the remaining 4/10 patients. All those 14 patients with IBD-associated SpA were under TNF inhibitors just before starting VDZ. Finally, new onset of SpA induced by VDZ was reported in 1 patient.Abstract OP0029 – Table 1Characteristics of patients and main resultsVariablen=171 Age (years), mean±SD37.8±12.9Female gender, n (%)110 (64.3)Body mass index (kg/m²), mean±SD23.7 (4.8)Type of disease, n (%)- Crohn’s disease- Ulcerative colitis 104 (60.8)67 (39.2)Duration of disease (years), mean±SD10.5 (7.6)Duration of follow-up under vedolizumab (months), mean±SD14.3 (12.0)IBD-associated SpA, n (%)- No history- History (inactive at initiation of VDZ)- Active at initiation of VDZ 157 (91.8)10 (5.8)4 (2.4)Clinical benefit on SpA following initiation of VDZ (n=4)- No clinical benefit- Improvement 4/4 (100)0/4 (0)Exacerbation of SpA in patients with clinical remission at initiation of VDZ (n=10)- Yes- No 6 (60)4 (40)New onset of SpA induced by VDZ1 (<1)ConclusionsVedolizumab does not seem to show any efficacy in IBD-associated SpA and might even induce exacerbation or new onset of SpA. Inception cohort studies are needed to better evaluate the effect of vedolizumab on joint manifestations.References1 Varkas G, Thevissen K, De Brabanter G, et al. Ann Rheum Dis2017May;76(5):878–881.2 Orlando A, Orlando R, Ciccia F, et al. Ann Rheum Dis2017Sep;76(9):e31.Disclosure of InterestNone declared
Terbium-155 has been identified for its potential for single-photon emission computed tomography (SPECT) in nuclear medicine. For activity measurements, an accurate and precise half-life of this ...radionuclide is required. However, the currently evaluated half-life of 5.32(6) d with a relative standard uncertainty of 1.1% determines the precision possible. Limited literature for the half-life measurements of this radionuclide is available and all reported investigations are prior to 1970. Further measurements are therefore needed to confirm the accuracy and improve the precision of the half-life for its use in the clinical setting. Two samples produced and mass separated at the CERN-MEDICIS facility have been measured at the National Physical Laboratory by two independent techniques: liquid scintillation counting and high-purity germanium gamma-ray spectrometry. A half-life of 5.2346(36) d has been determined from the weighted mean of the half-lives determined by the two techniques. The half-life reported in this work has shown a relative difference of 1.6% to the currently evaluated half-life and has vastly improved the precision.
•Mass separated and radiochemically purified samples used to determine the half-life.•A half-life of 5.2346(36) d has been determined from two independent techniques.•A relative deviation of 1.6% from current evaluated half-life observed.•An order of magnitude increase in the precision has been achieved.
All-cellulose composites were prepared by partly dissolving microcrystalline cellulose (MCC) in an 8.0 wt% LiCl/DMAc solution, then regenerating the dissolved portion. Wide-angle X-ray scattering ...(WAXS) and solid-state ¹³C NMR spectra were used to characterize molecular packing. The MCC was transformed to relatively slender crystallites of cellulose I in a matrix of paracrystalline and amorphous cellulose. Paracrystalline cellulose was distinguished from amorphous cellulose by a displaced and relatively narrow WAXS peak, by a 4 ppm displacement of the C-4 ¹³C NMR peak, and by values of T₂(H) closer to those for crystalline cellulose than disordered polysaccharides. Cellulose II was not formed in any of the composites studied. The ratio of cellulose to solvent was varied, with greatest consequent transformation observed for c < 15%, where c is the weight of cellulose expressed as % of the total weight of cellulose, LiCl and DMAc. The dissolution time was varied between 1 h and 48 h, with only small additional changes achieved by extension beyond 4 h.
Since its commissioning in December 2017, the CERN-MEDICIS facility has been providing non-conventional radionuclides for research in nuclear medicine. Benefitting from decades of experience in the ...production of radioactive ion beams and in the mass separation process from the ISOLDE facility at CERN, MEDICIS quickly became a worldwide key player in the supply of novel medical isotopes dedicated to research in the fields of cancer imaging, diagnostics, and radiation therapy.
After a few years of operation, successful collections have been performed on a large panel of radionuclides such as 128Ba, 149,152,155Tb, 153Sm, 165,167Tm, 169Er, 175Yb, 191Pt, and 225,227Ac. Several milestones have been achieved on the output of the facility, such as the collection of 0.5 GBq of 175Yb, and a total separation efficiency higher than 50% reached for 167Tm in 2020. These collections led to notable recent in-vitro and preclinical results in targeted radionuclide therapy achieved with high molar activity 175Yb and 153Sm products.
Constant developments are ongoing, such as innovative target designs, molecular formation to improve the release of some specific isotopes, laser development in the dedicated MELISSA laboratory, study of new implantation foil materials, and post-collection radiochemistry.
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