340 research outputs found
Improving case mix for description and funding in rehabilitation in France: additive model is better than tree-classification
Fabrication of ultrathin MIL-96(Al) films and study of CO2 adsorption/desorption processes using quartz crystal microbalance
This contribution reports the fabrication and characterization of ultrathin films of nanoparticles of the water stable microporous Al tricarboxylate metal organic framework MIL-96(Al). The preparation of MOF dispersions in chloroform has been optimized to obtain dense monolayer films of good quality, without nanoparticle agglomeration, at the air-water interface that can be deposited onto solid substrates of different nature without any previous substrate functionalization. The MOF studied shows great interest for CO2 capture because it presents Al3+ Lewis centers and hydroxyl groups that strongly interact with CO2 molecules. A comparative CO2 adsorption study on drop-cast, Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) films using a Quartz Crystal Microbalance-based setup (QCM) has revealed that the CO2 uptake depends strongly on the film fabrication procedure and the storage conditions. Noteworthy the CO2 adsorption capacity of LB films is increased by 30% using a simple and green treatment (immersion of the film into water during 12 h just after film preparation). Finally, the stability of LB MOF monolayers upon several CO2 adsorption/desorption cycles has been demonstrated, showing that CO2 can be easily desorbed from the films at 303 K by flowing an inert gas (He). These results show that MOF LB monolayers can be of great interest for the development of MOF-based devices that require the use of very small MOF quantities, especially gas sensors
Risk Factors for Buruli Ulcer, Benin
Disease was associated with age, place of residence, and water sources in all age groups
Optimization of MIL-178(Fe) and Pebax® 3533 loading in mixed matrix membranes for CO2 capture
Global warming is considered as a consequence of extensive use of fossil fuels. Post combustion CO2 capture is an interesting and alternative solution where mixed matrix membranes (MMMs) can be an exciting candidate. This research focuses on the optimization of MMM composition consisting of Pebax® 3533 as the polymer matrix and porous coordination polymer (PCP) MIL-178(Fe) as a filler for gas separation application. MIL-178(Fe) characterized with SEM, TEM and TGA were applied to compare bare polymer and MMM. Optimum composition of the MMM obtained was 5 wt.% MIL-178(Fe) in Pebax® 3533. Average thickness of the optimized dense MMM was 116 ± 8 µm. Such MMM showed CO2 permeability and CO2/N2 selectivity of 312 ± 5 Barrer and 25.0 ± 0.5, respectively, 12% and 25% improved regarding the bare membrane. Additionally, optimum MMM was applied for CO2/CH4 separation and successfully compared in terms of improved CO2 permeability and CO2/CH4 selectivity
cyclo-Tetra-μ-oxido-tetrakis[(acetylacetonato-κ2 O,O′)bis(ethanolato-κO)niobium(V)]
The asymmetric unit of the title tetranuclear niobium(V) compound, [Nb4(C2H5O)8(C5H7O2)4O4], contains two NbV atoms, two bridging O atoms, two acetylacetonate and four ethanolate ligands. Each NbV atom is six-coordinated by the bridging O atoms, two ethanolate and one chelating acetylacetonate ligands. The Nb—O distances vary between 1.817 (2) and 2.201 (2) Å and the O—Nb—O angles vary between 78.88 (8) and 102.78 (9)°, illustrating the significant distortion from ideal ocahedral geometry. The rest of the tetranuclear unit is generated through an inversion centre. The C atoms of two of the ethanolate molecules are disordered over two sites [occupancy ratio 0.601 (12):0.399 (12)]
Toward an Understanding of the Microstructure and Interfacial Properties of PIMs/ZIF-8 Mixed Matrix Membranes
A study integrating advanced experimental
and modeling tools was
undertaken to characterize the microstructural and interfacial properties
of mixed matrix membranes (MMMs) composed of the zeolitic imidazolate
framework ZIF-8 nanoparticles (NPs) and two polymers of intrinsic
microporosity (PIM-1 and PIM-EA-TB). Analysis probed both the initial
ZIF-8/PIM-1 colloidal suspensions and the final hybrid membranes.
By combination of dynamic light scattering (DLS) and transmission
electron microscopy (TEM) analytical and imaging techniques with small-angle
X-ray scattering (SAXS), the colloidal suspensions were shown to consist
mainly of two distinct kinds of particles, namely, polymer aggregates
of about 200 nm in diameter and densely packed ZIF-8-NP aggregates
of a few 100 nm in diameter with a 3 nm thick polymer top-layer. Such
aggregates are likely to impart the granular texture of ZIF-8/PIMs
MMMs as shown by SEM-XEDS analysis. At the molecular scale, modeling
studies showed that the surface coverage of ZIF-8 NPs by both polymers
appears not to be optimal with the presence of microvoids at the interfaces
that indicates only a moderate compatibility between the polymer and
ZIF-8. This study shows that the microstructure of MMMs results from
a complex interplay between the ZIF-8/PIM compatibility, solvent,
surface chemistry of the ZIF-8 NPs, and the physicochemical properties
of the polymers such as molecular structure and rigidity
Buruli Ulcer Recurrence, Benin
Access to high-quality treatment prevents Buruli ulcer recurrence
Mycobacterium ulcerans Disease (Buruli Ulcer) in Rural Hospital, Southern Benin, 1997–2001
Hospital data show that Buruli ulcer is highly endemic in southern Benin
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