Photothermal deflection in multilayer coatings: modeling and experiment

A model of the photothermal deflection signal in multilayer coatings is presented that takes into account optical interference effects and heat flow within the stack. Measurements are then taken of high-reflectivity HfO2/SiO2 ultraviolet mirrors made by plasma ion assisted deposition and compared to calculations. Good agreement is found between the experimental results and the model. Using this model for the calibration and the setup described, one can measure absorption in multilayer coatings accurately down to 10(-7) of the incident power.     

A review of learning demands in instructional animations: The educational effectiveness of animations unfolds if the features of change need to be learned

In a systematic review, 194 studies on learning from animation were analysed. The analysis covers the learning domains, the representational characteristics of the animations, the assessed perceptual and cognitive achievements, and the assessment formats. Research on learning from animation focuses on assessing conceptual at the neglect of kinematic mental models. This is in contrast to an important rationale for making use of animations: that it needs to be learned what animations can specifically display, namely, how change in space and time occurs. This might explain why meta-analyses which compared the effectiveness of animations and static pictures found merely small overall effect sizes in favour of animations. To confirm this hypothesis, one meta-analysis was re-analysed with a new moderator. It encodes whether the features of the displayed changes were relevant to learning. Learning from animations was significantly more successful than learning from static pictures, if the features of the displayed changes had to be learned.     

Porous Porphyrin‐Based Organosilica Nanoparticles for NIR Two‐Photon Photodynamic Therapy and Gene Delivery in Zebrafish

Periodic mesoporous organosilica nanoparticles emerge as promising vectors for nanomedicine applications. Their properties are very different from those of well‐known mesoporous silica nanoparticles as there is no silica source for their synthesis. So far, they have only been synthesized from small bis‐silylated organic precursors. However, no studies employing large stimuli‐responsive precursors have been reported on such hybrid systems yet. Here, the synthesis of porphyrin‐based organosilica nanoparticles from a large octasilylated metalated porphyrin precursor is described for applications in near‐infrared two‐photon‐triggered spatiotemporal theranostics. The nanoparticles display unique interconnected large cavities of 10–80 nm. The framework of the nanoparticles is constituted with J‐aggregates of porphyrins, which endows them with two‐photon sensitivity. The nanoparticle efficiency for intracellular tracking is first demonstrated by the in vitro near‐infrared imaging of breast cancer cells. After functionalization of the nanoparticles with aminopropyltriethoxysilane, two‐photon‐excited photodynamic therapy in zebrafish is successfully achieved. Two‐photon photochemical internalization in cancer cells of the nanoparticles loaded with siRNA is also performed for the first time. Furthermore, siRNA targeting green fluorescent protein complexed with the nanoparticles is delivered in vivo in zebrafish embryos, which demonstrates the versatility of the nanovectors for biomedical applications.     

Amino acid catabolism by Lactococcus lactis during milk fermentation

Two wild-type Lactococcus lactis strains isolated from naturally Tunisian fermented milk (Leben), and one laboratory strain, were used to investigate the ability of L. lactis to transform amino acids into aroma compounds during milk fermentation. The α-ketoacid acceptor used for leucine transamination, the first step of catabolism, was identified by gas chromatography/mass spectrometry analysis of the ¹⁵N-labelled amino acids that formed from ¹⁵N-labelled leucine in fermented milk. Furthermore, the amino acids produced or catabolized by the laboratory strain via transamination were identified by comparing the free amino acids in milk fermented with the wild-type strain and the double mutant for aromatic and branched-chain aminotransferases, which cannot transaminate amino acids. The three L. lactis strains strongly catabolized leucine and valine during milk fermentation. The principal amino acid formed via leucine and valine transamination was glutamate indicating that α-ketoglutarate was the principal α-ketoacid acceptor and was generated during milk fermentation.     

Reducing the warp of sheet glass

Abstract— Many leading technologies, such as flat‐panel displays and precision optics, require sheet glass with exceptional surface qualities. Commercially available sheet glass of <1 ‐mm thickness typically has a surface warp on the order of hundreds of microns, rendering it a challenge to utilize progressively thinner sheets. A novel method of shaping individual sheets and ribbons of glass is presented which utilizes porous mandrels. This method reduces the surface warp of the ribbon while in its hot state without contacting its surface. Sheet glass is inserted between two parallel porous mandrels spaced apart by a predefined distance. A thin layer of pressurized gas flows through each mandrel and out against the glass surfaces. The local gap between the warped glass sheet and the flat mandrel determines the local pressure on the glass. When in its heated and soft state, the glass sheet's surface is changed by this pressure with a strong restorative force proportional to the inverse of the gap cubed, which tends to flatten the sheet. By using flat mandrels and controlled pressurized gas at elevated temperatures, the outcome is a sheet of glass with a surface warp of a few microns while retaining its original pristine optical surface qualities.     

Noise and gain band management of thulium-doped fiber amplifierwith dual-wavelength pumping schemes

Three dual-wavelength pumping schemes (1550 nm + 1064, 1047, or 1400 nm) have been experimentally assessed for the thulium-doped fiber amplifier in terms of power and noise performance. It is shown that 1047- and 1550-nm pumping gives a better power performance than 1064- and 1550-nm pumping at fixed gain peak wavelength (GPW). In addition, the most efficient pumping scheme appears to be 1400- and 1550-nm pumping for GPW higher than 1475 nm, and 1047 and 1550 nm for lower GPW. Noise figures lower than 6 db (with -5-dBm signal input power) are exhibited regardless the pumping schemes (although a 0.8-dB increase is reported for the 1400- and 1550-nm pumping)