Navigation/traffic control satellite mission study. Volume 3 - System concepts

Satellite network for air traffic control, solar flare warning, and collision avoidanc

Evaluation of biomechanical effects of interocclusal surfaces on the mandible

ABSTRACT Introduction: Only few studies in the literature employ a mathematical model in the evaluation of the stress which follows the application of loads and constraints onto the mandible. Therefore, new approaches are needed so that the study of this phenomenon can rely less on the clinical hypothesis and experience of the operator, while taking advantage of the many benefits that virtual representations and mathematical calculations present. Aim of the study is to determine, by means of the finite element method (FEM), the stress produced onto the mandible as a result of the application of a force on itself, in association or not to the perioral musculature and according to the dental support given by the positioning of an interocclusal surface at three different levels: mesial, intermediate and distal. Aim: The aim is to allow a more objective evaluation of this phenomenon, its absolute repeatability, as well as to acquire important clinical informations concerning the role of orthodontic and gnathologic appliances. Materials and methods: Starting from a 1:1 scale model of the mandible (human adult male), a virtual three - dimensional (3D) representation was first obtained thanks to a dedicate software; it was then imported into a second software in order to permit the discretization into finite elements of the virtual model and the attribution of its mechanical properties. Finally, thanks to a specific software, it was possible to simulate the presence of load and constraints and to evaluate the stress status by using pseudo - colors. Results: The stress generated following the application of a force onto the mandible, undergoes significant variations in relation to the dental support and the presence or absence of the perioral musculature. Conclusions: Following the results of our research, we consider FEM as a valid and interesting method for this purpose, however additional FEM conducted studies are necessary in order to assess this phenomenon in more detail and determine the role of the perioral musculature as well as the possible clinical implications

SAR Studies on Curcumin's Pro-inflammatory Targets: Discovery of Prenylated Pyrazolocurcuminoids as Potent and Selective Novel Inhibitors of 5-Lipoxygenase.

The anticarcinogenic and anti-inflammatory properties of curcumin have been extensively investigated, identifying prostaglandin E2 synthase (mPGES)-1 and 5-lipoxygenase (5-LO), key enzymes linking inflammation with cancer, as high affinity targets. A comparative structure-activity study revealed three modifications dissecting mPGES-1/5-LO inhibition, namely (i) truncation of the acidic, enolized dicarbonyl moiety and/or replacement by pyrazole, (ii) hydrogenation of the interaryl linker, and (iii) (dihydro)prenylation. The prenylated pyrazole analogue 11 selectively inhibited 5-LO, outperforming curcumin by a factor of up to 50, and impaired zymosan-induced mouse peritonitis along with reduced 5-LO product levels. Other pro-inflammatory targets of curcumin (i.e., mPGES-1, cyclooxygenases, 12/15-LOs, nuclear factor-κB, nuclear factor-erythroid 2-related factor-2, and signal transducer and activator of transcription 3) were hardly affected by 11. The strict structural requirements for mPGES-1 and 5-LO inhibition strongly suggest that specific interactions rather than redox or membrane effects underlie the inhibition of mPGES-1 and 5-LO by curcumin

Etude biochimique de la pulpe dentaire de veau

A biochemical study of dental pulp of calves has been performed concerning:a) peroxydabilityb) A, E, C vitamins contentc) glutation (GSH) contentd) presence of paramagnetic compoundse) phosphorylation ratioThe dental pulp from incisives of 5 months old calves has been preserved. Immediately after decapitation the pulp was immersed in liquid nitrogen. Chromatographie (HPLC) and spectroscopic (NMR-ESR) techniques have been used.GSH in dental pulp are present and dosable (4.56 +/-0.08 n moles/mg prot.) and GSSG (1.05 +/-0.01 n moles/mg prot.).Because of blood traces in the extracted pulps, the AA. have determined the hemoglobin (Hb) dosage and GSH of erythrocytary derivation (Fig. 1).After deduction of GSH of erythrocytary derivation, the GSH really present in the pulp was 4.41 n moles/mg prot. and the GSSG was 0.90 n moles/mg prot.Peroxydability of the dental pulp has been evaluated with Lowry method with dental pulp homogenate and rat liver homogenate (see Table 1).The ESR spectre shows 4 resonances with the following values: g. 2.24 - 2.04 - 2.00 - 1.97; there are some free intermediary radicals (gr. - 2.00) (Fig.2).The NMR spectre shows the presence of ATP (0.22 n moles/g) of inorganic phosphate (16.58 n moles g) (Fig.3).The pulp seems to have a lot of antioxydant factors. The next researches will be to study E, A and C vitamins concentrations. This high presence of GSH and GSSG may be an embryonary peculiarity.Une étude biochimique de la pulpe dentaire a été entreprise pour étudier les propriétés antioxydantes et leurs interactions avec le métabolisme énergétique et les équilibres redox de la pulpe dentaire de veau. Le GSH réduit et oxydé (GSSG) a été mesuré et la spectroscopie avec ESR (Electron Spin Résonance) a été utilisée pour la recherche des substances paramagnétiques et la résonance magnétique nucléaire (NMR) pour la détermination des métabolites phosphorylés de petit poids moléculaire. Après la soustraction de la quantité de GSH érythrocytaire, le GSH présent dans la pulpe est resté identique 4,41 n moles/mg prot. (GSH) et 0.90 n moles/mg n moles/mg prot. (GSSG). La péroxydation lipidique de la pulpe dentaire a été étudiée. Le spectre ESR montre 4 résonances, respectivement de valeurs de G de 2.24, 2.04, 2.00, 1.97.L’analyse des résultats montre l’existence d’une petite quantité de radicaux libres intermédiaires (g-2.00) dépendant du métabolisme tissulaire. Le spectre NMR a montré la présence d’ATP (0.22 n moles/g) et de phosphate inorganique (16.50 n moles/g)

Managing phase purities and crystal orientation for high-performance and photostable cesium lead halide perovskite solar cells

Inorganic perovskites with cesium (Cs+) as the cation have great potential as photovoltaic materials if their phase purity and stability can be addressed. Herein, a series of inorganic perovskites is studied, and it is found that the power conversion efficiency of solar cells with compositions CsPbI1.8Br1.2, CsPbI2.0Br1.0, and CsPbI2.2Br0.8 exhibits a high dependence on the initial annealing step that is found to significantly affect the crystallization and texture behavior of the final perovskite film. At its optimized annealing temperature, CsPbI1.8Br1.2 exhibits a pure orthorhombic phase and only one crystal orientation of the (110) plane. Consequently, this allows for the best efficiency of up to 14.6% and the longest operational lifetime, T S80, of ≈300 h, averaged of over six solar cells, during the maximum power point tracking measurement under continuous light illumination and nitrogen atmosphere. This work provides essential progress on the enhancement of photovoltaic performance and stability of CsPbI3 − x Brx perovskite solar cells

Chloride-Based Additive Engineering for Efficient and Stable Wide-Bandgap Perovskite Solar Cells

Metal halide perovskite based tandem solar cells are promising to achieve power conversion efficiency beyond the theoretical limit of their single-junction counterparts. However, overcoming the significant open-circuit voltage deficit present in wide-bandgap perovskite solar cells remains a major hurdle for realizing efficient and stable perovskite tandem cells. Here, a holistic approach to overcoming challenges in 1.8 eV perovskite solar cells is reported by engineering the perovskite crystallization pathway by means of chloride additives. In conjunction with employing a self-assembled monolayer as the hole-transport layer, an open-circuit voltage of 1.25 V and a power conversion efficiency of 17.0% are achieved. The key role of methylammonium chloride addition is elucidated in facilitating the growth of a chloride-rich intermediate phase that directs crystallization of the desired cubic perovskite phase and induces more effective halide homogenization. The as-formed 1.8 eV perovskite demonstrates suppressed halide segregation and improved optoelectronic properties

Alumina nanoparticle interfacial buffer layer for low‐bandgap lead‐tin perovskite solar cells

Mixed lead-tin (Pb:Sn) halide perovskites are promising absorbers with narrow-bandgaps (1.25–1.4 eV) suitable for high-efficiency all-perovskite tandem solar cells. However, solution processing of optimally thick Pb:Sn perovskite films is notoriously difficult in comparison with their neat-Pb counterparts. This is partly due to the rapid crystallization of Sn-based perovskites, resulting in films that have a high degree of roughness. Rougher films are harder to coat conformally with subsequent layers using solution-based processing techniques leading to contact between the absorber and the top metal electrode in completed devices, resulting in a loss of VOC, fill factor, efficiency, and stability. Herein, this study employs a non-continuous layer of alumina nanoparticles distributed on the surface of rough Pb:Sn perovskite films. Using this approach, the conformality of the subsequent electron-transport layer, which is only tens of nanometres in thickness is improved. The overall maximum-power-point-tracked efficiency improves by 65% and the steady-state VOC improves by 28%. Application of the alumina nanoparticles as an interfacial buffer layer also results in highly reproducible Pb:Sn solar cell devices while simultaneously improving device stability at 65 °C under full spectrum simulated solar irradiance. Aged devices show a six-fold improvement in stability over pristine Pb:Sn devices, increasing their lifetime to 120 h