33 research outputs found
Variable base-word positioning in English blends
Cet article explore les conditions qui rĂ©sultent du positionnement variable du terme source dans les amalgames anglais, dans lesquels les mĂȘmes termes sources ont un ordre variable, crĂ©ant ainsi deux amalgames diffĂ©rents, câest-Ă -dire des doublets dâamalgames. Pour les doublets dâamalgames non synonymiques, tels que (egg Ă prĂ©gnant >) Ă©ggnant âpregnant with eggâ et prĂ©gegg âegg that counts down pregnancyâ, le facteur principal est que dans les amalgames endocentriques, le terme source qui constitue la tĂȘte sĂ©mantique se place Ă droite. Pour les doublets dâamalgames synonymiques, tels que plĂșmpricot ~ ĂĄpriplum âplumâapricot hybridâ () Ă©ggnant âpregnant with eggâ and prĂ©gegg âegg that counts down pregnancyâ, the main factor is that in endocentric blends, the base word that contributes the semantic head is rightâaligned. In synonymous blend doublets, such as plĂșmpricot ~ ĂĄpriplum âplumâapricot hybridâ (< plum Ă ĂĄpricot), variable baseâword positioning results from at least four factors interacting: (i) segmental faithfulness â maximizing segmental similarity; (ii) PÄáčiniâs law â positioning the short base word before the long one; (iii) monosyllabic integrity â keeping the monosyllabic base word in the same syllable; and (iv) syntagmatic faithfulness â matching the linear order of the base words to their order in a wouldâbe syntactic constituent
Cell refinement of CsPbBr3 perovskite nanoparticles and thin films
In this work, we performed a detailed study of the phase transformations and structural unit cell parameters of CsPbBr3 nanoparticles (NPs) and thin films. In situ X-ray diffraction patterns were acquired as a function of temperature, where the positions and widths of the diffraction peaks were systematically tracked upon heating and cooling down to room temperature (RT). Scanning electron microscopy provides physical insight on the CsPbBr3 thin films upon annealing and transmission electron microscopy gives physical and crystallographic information for the CsPbBr3 NPs using electron diffraction. The secondary phase(s) CsPb2Br5 (and CsPb4Br6) are clearly observed in the XRD patterns of both nanoparticles and thin films upon heating to 500 K, whilst from 500 K to 595 K, these phases remain in small amounts and are kept like this upon cooling down to RT. However, in the case of thin films, the CsPb2Br5 secondary phase disappears completely above 580 K and pure cubic CsPbBr3 is observed up to 623 K. The CsPbBr3 phase is then kept upon cooling down to RT, achieving pure CsPbBr3 phase. This study provides detailed understanding of the phase behavior vs. temperature of CsPbBr3 NPs and thin films, which opens the way to pure CsPbBr3 phase, an interesting material for optoelectronic applications
Neuroprotective Effect of Hyperbaric Oxygen Therapy on Anterior Ischemic Optic Neuropathy
The study investigated the therapeutic effect of hyperbaric oxygen (HBO) on anterior ischemic optic neuropathy in a rodent model (rAION). rAION was laser-induced in one eye of 63 mice. The fellow (uninjured) eye served as an internal control. Thirty-three mice underwent two 90-min sessions of 100% oxygen (2âatm) treatment immediately following injury and one session daily thereafter for up to 14âdays. The remaining mice were untreated. Retinas were harvested at different time points, and mRNA levels of various genes were analyzed by real-time polymerase chain reaction and histologic study. Untreated mice: day 1 post-rAION â SOD-1 (oxidative-stress-related) decreased to 82% of control (uninjured eye) levels (Pâ<â0.05), Caspase-3 (proapoptotic) decreased to 89%, Bcl-xL mildly increased (117%; all NS); day 3 â HO-1 and endothelial nitric oxide synthase (eNOS; ischaemia-related) decreased to 74%, and Bcl-2-associated X protein, Caspase-3, and B-cell lymphoma 2 (Bcl-2; apoptotic) increased by 170, 120, and 111%, respectively (all NS); day 21 â HO-1 increased to 222% (NS) and eNOS decreased to 48% (Pâ<â0.05). Treated mice: day 1 â SOD-1 and Caspase-3 remained unchanged, Bcl-2 and Bcl-xL mildly increased (112 and 126% respectively); day 3 â HO-1 and eNOS increased, apoptosis-related gene decreased; day 21 â SOD-1 decreased whereas eNOS increased (Pâ<â0.05), and HO-1 increased to a lesser degree than without treatment. None of the oxygen-treated animals had retinal ganglion cell loss or a decrease in Thy-1 expression. In conclusion, HBO treatment after rAION induction influences the expression of apoptosis-related genes as well as oxidative-stress-induced and ischaemia-related genes and may exert a neuroprotective effect
Enhancing Stability and Photostability of CsPbI3 by Reducing Its Dimensionality
Full inorganic perovskites display their potential to function as stable photovoltaic materials better than the hybrid organicâinorganic perovskites. However, to date, the cesium lead iodide perovskite, which displays a promising absorbance range, has suffered from low stability, which degrades to a nonactive photovoltaic phase rapidly. In this work, we show that the black phase of cesium lead iodide can be stabilized when the perovskite dimensionality is reduced. X-ray diffraction, absorbance, and scanning electron microscopy were used to follow the degradation process of various dimensionalities under room conditions and 1 sun illumination. When comparing the effect on the stability and photostability of cesium lead iodide with linear or aromatic barrier molecules, the aromatic barrier molecule displays better photostability for over 700 h without degradation under continuous 1 sun illumination than does the linear barrier molecule. Theoretical calculations show that the addition of the barrier molecule makes a different charge distribution over the perovskite structure, which stabilizes the CsPbI3 black phase. This work provides the possibility to use the CsPbI3 perovskite as a stable photovoltaic material in solar cells
Structural and Quantitative Investigation of Perovskite Pore Filling in Mesoporous Metal Oxides
In recent years, hybrid organicâinorganic perovskite light absorbers have attracted much attention in the field of solar cells due to their optoelectronic characteristics that enable high power conversion efficiencies. Perovskite-based solar cellsâ efficiency has increased dramatically from 3.8% to more than 20% in just a few years, making them a promising low-cost alternative for photovoltaic applications. The deposition of perovskite into a mesoporous metal oxide is an influential factor affecting solar cell performance. Full coverage and pore filling into the porous metal oxide are important issues in the fabrication of highly-efficient mesoporous perovskite solar cells. In this work, we carry out a structural and quantitative investigation of CH3NH3PbI3 pore filling deposited via sequential two-step deposition into two different mesoporous metal oxidesâTiO2 and Al2O3. We avoid using a hole conductor in the perovskite solar cells studied in this work to eliminate undesirable end results. Filling oxide pores with perovskite was characterized by Energy Dispersive X-ray Spectroscopy (EDS) in Transmission Electron Microscopy (TEM) on cross-sectional focused ion beam (FIB) lamellae. Complete pore filling of CH3NH3PbI3 perovskite into the metal oxide pores was observed down to X-depth, showing the presence of Pb and I inside the pores. The observations reported in this work are particularly important for mesoporous Al2O3 perovskite solar cells, as pore filling is essential for the operation of this solar cell structure. This work presents structural and quantitative proof of complete pore filling into mesoporous perovskite-based solar cells, substantiating their high power conversion efficiency
Hybrid Lead Halide Iodide and Lead Halide Bromide in Efficient Hole Conductor Free Perovskite Solar Cell
In this work we used CH<sub>3</sub>NH<sub>3</sub>PbI<sub><i>n</i></sub>Br<sub>3â<i>n</i></sub> (where 0 †<i>n</i> †3)
as hole conductor and light harvester in the solar cell. Various concentrations
of methylammonium iodide and methylammonium bromide were studied which
reveal that any composition of the hybrid CH<sub>3</sub>NH<sub>3</sub>PbI<sub><i>n</i></sub>Br<sub>3â<i>n</i></sub> can conduct holes. The hybrid perovskite was deposited in
two steps, separating it to two precursors to allow better control
of the perovskite composition and efficient tuning of its band gap.
The X-ray diffraction reveals the change in the lattice parameter
due to the introducing of the Br<sup>â</sup> ions. The hybrid
iodide/bromide perovskite hole conductor free solar cells show very
good stability, their power conversion efficiency achieved 8.54% under
1 sun illumination with current density of 16.2 mA/cm<sup>2</sup>.
The results of this work open the possibility for graded structure
of perovskite solar cells without the need for hole conductor
Impact of Antisolvent Treatment on Carrier Density in Efficient Hole-Conductor-Free Perovskite-Based Solar Cells
This
work demonstrates antisolvent treatment of organo-metal halide
perovskite film in hole-conductor-free perovskite-based solar cell,
achieving impressive power conversion efficiency of 11.2% for hole-conductor-free
cells with gold contact. We found that antisolvent (toluene) surface
treatment affects the morphology of the perovskite layer, and importantly,
it also affects the electronic properties of the perovskite. Conductive
atomic force microscopy (cAFM) and surface photovoltage show that
the perovskite film becomes more conductive after antisolvent treatment.
Moreover, the antisolvent treatment suppresses the hysteresis commonly
obtained for perovskite-based solar cells. When the perovskite alone
is characterized, a <i>I</i>â<i>V</i> plot
of a single perovskite grain measured by cAFM shows that hysteresis
vanishes after toluene treatment. During toluene treatment, excess
halide and methylammonium ions are removed from the perovskite surface,
leading to a net positive charge on the Pb atoms, resulting in a more
conductive perovskite surface, which is beneficial for the hole-conductor-free
solar cell structure. The reliability of the surface treatment was
proved by calculating the statistical parameters <i>Z</i> score and <i>p</i> value, which were 2.5 and 0.012, respectively.
According to these values, it can be concluded with 95% confidence
that the average efficiency of cells fabricated via surface treatment
is greater than the average efficiency of cells without surface treatment.
The statistical data support the impact of surface treatment on the
photovoltaic performance of perovskite solar cells
Evaluating the Synergistic Neutralizing Effect of Anti-Botulinum Oligoclonal Antibody Preparations
<div><p>Botulinum neurotoxins (BoNT) are considered some of the most lethal known substances. There are seven botulinum serotypes, of which types A, B and E cause most human botulism cases. Anti-botulinum polyclonal antibodies (PAbs) are currently used for both detection and treatment of the disease. However, significant improvements in immunoassay specificity and treatment safety may be made using monoclonal antibodies (MAbs). In this study, we present an approach for the simultaneous generation of highly specific and neutralizing MAbs against botulinum serotypes A, B, and E in a single process. The approach relies on immunization of mice with a trivalent mixture of recombinant C-terminal fragment (Hc) of each of the three neurotoxins, followed by a parallel differential robotic hybridoma screening. This strategy enabled the cloning of seven to nine MAbs against each serotype. The majority of the MAbs possessed higher anti-botulinum ELISA titers than anti-botulinum PAbs and had up to five orders of magnitude greater specificity. When tested for their potency in mice, neutralizing MAbs were obtained for all three serotypes and protected against toxin doses of 10 MsLD<sub>50</sub>â500 MsLD<sub>50</sub>. A strong synergistic effect of up to 400-fold enhancement in the neutralizing activity was observed when serotype-specific MAbs were combined. Furthermore, the highly protective oligoclonal combinations were as potent as a horse-derived PAb pharmaceutical preparation. Interestingly, MAbs that failed to demonstrate individual neutralizing activity were observed to make a significant contribution to the synergistic effect in the oligoclonal preparation. Together, the trivalent immunization strategy and differential screening approach enabled us to generate highly specific MAbs against each of the A, B, and E BoNTs. These new MAbs may possess diagnostic and therapeutic potential.</p></div