Multigigahertz range-Doppler correlative signal processing in optical memory crystals

Analog optical signal processing of complex radio-frequency signals for range-Doppler radar information is theoretically described and experimentally demonstrated using crystalline optical memory materials and off-the-shelf photonic components. A model of the range-Doppler processing capability of the memory material for the case of single-target detection is presented. Radarlike signals were emulated and processed by the memory material; they consisted of broadband (> 1 GHz), spread-spectrum, pseudorandom noise sequences of 512 bits in length, which were binary phase-shift keyed on a 1.9 GHz carrier and repeated at 100 kHz over 7.5 ms. Delay (range) resolution of 8 ns and Doppler resolution of 130 Hz over 100 kHz were demonstrated.     

Raman spectra of biological samples: A study of preprocessing methods

In this study preprocessing of Raman spectra of different biological samples has been studied, and their effect on the ability to extract robust and quantitative information has been evaluated. Four data sets of Raman spectra were chosen in order to cover different aspects of biological Raman spectra, and the samples constituted salmon oils, juice samples, salmon meat, and mixtures of fat, protein, and water. A range of frequently used preprocessing methods, as well as combinations of different methods, was evaluated. Different aspects of regression results obtained from partial least squares regression (PLSR) were used as indicators for comparing the effect of different preprocessing methods. The results, as expected, suggest that baseline correction methods should be performed in advance of normalization methods. By performing total intensity normalization after adequate baseline correction, robust calibration models were obtained for all data sets. Combination methods like standard normal variate (SNV), multiplicative signal correction (MSC), and extended multiplicative signal correction (EMSC) in their basic form were not able to handle the baseline features present in several of the data sets, and these methods thus provide no additional benefits compared to the approach of baseline correction in advance of total intensity normalization. EMSC provides additional possibilities that require further investigation.     

A general non‐linear optimization algorithm for lower bound limit analysis

The non‐linear programming problem associated with the discrete lower bound limit analysis problem is treated by means of an algorithm where the need to linearize the yield criteria is avoided. The algorithm is an interior point method and is completely general in the sense that no particular finite element discretization or yield criterion is required. As with interior point methods for linear programming the number of iterations is affected only little by the problem size. Some practical implementation issues are discussed with reference to the special structure of the common lower bound load optimization problem, and finally the efficiency and accuracy of the method is demonstrated by means of examples of plate and slab structures obeying different non‐linear yield criteria. Copyright © 2002 John Wiley & Sons, Ltd.     

Systematic Investigation of Metabolic Oligosaccharide Engineering Efficiency in Intestinal Cells Using a Dibenzocyclooctyne-Monosaccharide Conjugate

Metabolic oligosaccharide engineering (MOE) of cells with synthetic monosaccharides can introduce functionality to the glycans of cell membranes. Unnatural sugars (e. g., peracetylated mannose-azide) can be expressed on the cell surface with the azide group in place. After MOE, the azide group can participate in a copper-free click reaction with an alkyne (e. g., dibenzocyclooctyne, DBCO) probe. This allows the metabolic fate of monosaccharides in cells to be understood. However, in a drug delivery context it is desirable to have azide groups on the probe (e. g. a drug delivery particle) and the alkyne (e. g. DBCO) on the cell surface. Consequently, the labelling efficiency of intestinal cell lines (Caco-2 and HT29-MTX-E12) treated with N-dibenzocyclooctyne-tetra-acetylmannosamine, and the concentration- and time-dependent labelling were determined. Furthermore, the labelling of mucus in HT29-MTX-E12 cells with DBCO was shown. This study highlights the potential for using MOE to target azide-functionalised probes to intestinal tissues for drug delivery applications.     

Does the emotional design of scaffolds enhance learning and motivational outcomes in game-based learning?

Background

In recent years, the importance of emotions in learning has been increasingly recognized. Applying emotional design to induce positive emotions has been considered a means to enhance the instructional effectiveness of digital learning environments. However, only a few studies have examined the specific effects of emotional design in game-based learning.

Objectives

This quasi-experimental study utilized a value-added research approach to investigate whether emotional design applied to scaffolding in a game-based learning environment improves learning and motivational outcomes more than emotionally neutral scaffolding.

Methods

A total of 138 participants, mean age of 11.5 (SD = 0.73) participated in the study. A total of 68 participants played the base version of a fraction learning game (Number Trace), where scaffolding was provided with emotionally neutral mathematical notations, and 70 participants played the value-added version of the game using emotionally designed animated scaffolding agents. Pre-and post-tests were used to measure conceptual fraction knowledge and self-reported measures of situational interest and situational self-efficacy to evaluate motivational outcomes.

Results and Conclusions

Our results indicate that the emotional design applied to scaffolds can improve the educational value of a game-based learning environment by enhancing players' situational interest and situational self-efficacy. However, although the intervention improved the participants' conceptual fraction knowledge, there was no significant difference between the scaffolding conditions in participants' learning outcomes.

Takeaways

The results suggest that emotional design can increase the educational impact of game-based learning by promoting the development of interest, as well as improving self-efficacy.     

Determination of O2 and CO2 transmission rate of whole packages and single perforations in micro-perforated packages for fruit and vegetables

Microperforated packages are in widespread use for whole and fresh-cut fruit and vegetables, and there is a need for a simple and cost efficient methodology to accurately determine gas transmission rates for different packages. This work demonstrates a static technique using a low cost gas analyser for determining the O₂ and CO₂-transmission rates and permselectivity for whole perforated and non-perforated packages stored at different temperatures. The work further demonstrated the possibility to calculate the transmission rates for single holes, and results for single perforations agreed well with results in other studies. The O₂- and CO₂-transmission rates in perforated packages were not significantly affected by temperature in the range 5–23 °C, whereas transmission rates increased with increasing temperature for non-perforated packages. Gas transmission measurements can be used within quality control, in the choice of appropriate packaging for different fruit and vegetables and as an important parameter in EMAP modelling.     

Benchmarking and Critical Design Considerations of Zero-Excess Li-Metal Batteries

Zero-excess Li metal batteries (ZELMBs), in which a Li-anode is formed in situ during charging, have received much attention in recent years. ZELMBs bear great potential to increase energy density and facilitate battery production, thereby reducing cost as well as material and energy consumption. Practical application of ZELMBs has so far been limited by challenges related to the non-uniform deposition behavior of Li, leading to inadequate performance and safety concerns. To address these issues, promising approaches have been developed in recent years, including modifications of the current collector, electrolyte, and cycling protocols. While these approaches improve the long-term stability of ZELMB, they also reduce the energy density by introducing inactive materials into the cell. Herein, critical design criteria for the various optimization approaches in ZELMB research are established. Nominal volumetric and gravimetric energy densities are determined based on the degree of modification. Thresholds are determined for each of the strategies at which the energy density gain of ZELMB vanishes compared to other cell configurations. These findings are compared to literature results to provide guidance for the further development of ZELMB.