Plastic deformation of synthetic quartz nanopillars by nanoindentation for multi-scale and multi-level security artefact metrics

Individual authentication using artefact metrics has received increasing attention, as greater importance has been placed on the security of individual information. These artefact metrics must satisfy the requirements of individuality, measurement stability, durability, and clone resistance, in addition to possessing unique physical features. In this study, we proposed that nanostructures of synthetic quartz (SQ) deposited on an SQ plate may provide sophisticated artefact metrics if morphological changes could be intentionally introduced into the SQ nanostructures at certain positions. We fabricated SQ nanopillars using a mass-production method (ultraviolet nanoimprint lithography) and investigated their mechanical deformation using nanoindentation with a spheroid diamond tip through a loading and unloading cycle. The SQ nanopillars with an aspect ratio of 1 (i.e., diameters D of 100 and 200 nm with corresponding heights H of 100 and 200 nm, respectively) could be plastically deformed without collapsing within a specified pillar-array format at programmed positions. The plastically deformed SQ nanopillar arrays demonstrated multi-scale (sub-millimetre, micrometre, and nanometre) and multi-level (shape, area, diameter, and height) individuality authentication and clone resistance. Because SQ is physically and chemically stable and durable, individuality authentication can be a highly reliable tool on Earth and in space.

Using Element Birth and Death Technique in Modeling Cumulative Molded Substrate Expansion before Singulation

Semiconductor packages are commonly assembled and molded in array format on a substrate strip before they are singulated into individual units. However, cumulative substrate expansion causes problems such as machine vacuum error or misaligned cut during singulation if the substrate expansion is not factored in. This study uses element birth and death technique in modeling the overall expansion of the molded substrate strip so that the predicted expansion could be considered in the singulation tooling design offsets. The expansion of the substrate was modeled with the different package assembly processes and thermal conditions. Modeling results showed that there is a cumulative increase in the length of the substrate as it passes through the different processes. The results are in agreement with actual substrate expansion prior to package singulation. This would not be captured when simulation is done only for the molded substrate without considering the cumulative contribution of the preceding processes. With the element birth and death technique in process-based thermomechanical modeling, substrate expansion could already be forecasted, and package assembly problems avoided.

Plastic Deformation of Synthetic Quartz Nanopillars by Nanoindentation for Multi-scale and Multi-level Security Artefact Metrics

Individual authentication using artefact metrics has received increasing attention as a greater importance has been placed on the security of individual information. These artefact metrics must satisfy the requirements of individuality, measurement stability, durability, and clone resistance, in addition to possessing unique physical features. In this study, we proposed that nanostructures of synthetic quartz (SQ) deposited on an SQ plate may provide such sophisticated artefact metrics if morphological changes can be intentionally introduced into the SQ nanostructures at certain positions. We fabricated SQ nanopillars using a mass-production method (namely ultraviolet nanoimprint lithography) and investigated their mechanical deformation using nanoindentation with a spherical diamond tip through loading and unloading cycles. The SQ nanopillars with an aspect ratio of 1 (i.e. diameters D of 100 and 200 nm and heights H of 100 and 200 nm, respectively) could be plastically deformed without collapsing within a specified pillar-array format at programmed positions. The plastically deformed SQ nanopillar arrays demonstrated multi-scale (sub-millimetre, micrometre, and nanometre) and multi-level (shape, area, diameter, and height) individuality authentication and clone resistance capabilities. Because SQ is physically and chemically stable and durable, the individuality authentication will be a highly reliable media on Earth and in space.

Using Icon Arrays to Communicate Gambling Information Reduces the Appeal of Scratch Card Games

The present study assessed how altering the presentation format of readily available gambling information influences individuals’ gambling-related judgments (e.g., their perceived odds of winning a prize). Across two experiments (N = 1,151), we find that using icon arrays to present gambling information reduces the appeal of scratch card games. That is, participants presented with gambling information in an icon array, as opposed to a non-graphical format, reported feeling less likely to win a prize, less excitement to play, and less urge to gamble on a scratch card game presented in a hypothetical gambling task. The present study highlights how presenting gambling information in a simple graphical format (i.e., an icon array) can impact gambling-related perceptions and judgments. Overall, we conclude that presenting readily available gambling information in an icon array format represents a simple yet promising tool for correcting gamblers’ often overly-optimistic perceptions and reducing the appeal of negative expected value scratch card games.

Adaption of a Conventional ELISA to a 96-well ELISA-Array for Measuring the Antibody Responses to Influenza virus proteins, viruses and vaccines

We describe an adaptation of conventional ELISA methods to an ELISA-Array format using non-contact Piezo printing of up to 30 spots of purified recombinant viral fusion proteins, vaccine and virus on 96 well high-protein binding plates. Antigens were printed in 1 nanoliter volumes of protein stabilizing buffer using as little as 0.25 nanograms of protein, 2000-fold less than conventional ELISA. The performance of the ELISA-Array was demonstrated by serially diluting n=8 human post-flu vaccination plasma samples starting at a 1/1000 dilution and measuring binding to the array of Influenza antigens. Plasma polyclonal antibody levels were detected using a cocktail of biotinylated anti-human kappa and lambda light chain antibodies, followed by a Streptavidin-horseradish peroxidase conjugate and the dose-dependent signal was developed with a precipitable TMB substrate. Intra- and inter-assay precision of absorbance units among the eight donor samples showed mean CVs of 4.8% and 10.8%, respectively. The plasma could be differentiated by donor and antigen with titer sensitivities ranging from 1 × 103 to 4 × 106, IC50 values from 1 × 104 to 9 × 106, and monoclonal antibody sensitivities in the ng/mL range. Equivalent sensitivities of ELISA versus ELISA-Array, compared using plasma and an H1N1 HA trimer, were achieved on the ELISA-Array printed at 0.25ng per 200um spot and 1000ng per ELISA 96-well. Vacuum-sealed array plates were shown to be stable when stored for at least 2 days at ambient temperature and up to 1 month at 4-8°C. By the use of any set of printed antigens and analyte matrices the methods of this multiplexed ELISA-Array format can be broadly applied in translational research.

Stretchable elastic synaptic transistors for neurologically integrated soft engineering systems

Artificial synaptic devices that can be stretched similar to those appearing in soft-bodied animals, such as earthworms, could be seamlessly integrated onto soft machines toward enabled neurological functions. Here, we report a stretchable synaptic transistor fully based on elastomeric electronic materials, which exhibits a full set of synaptic characteristics. These characteristics retained even the rubbery synapse that is stretched by 50%. By implementing stretchable synaptic transistor with mechanoreceptor in an array format, we developed a deformable sensory skin, where the mechanoreceptors interface the external stimulations and generate presynaptic pulses and then the synaptic transistors render postsynaptic potentials. Furthermore, we demonstrated a soft adaptive neurorobot that is able to perform adaptive locomotion based on robotic memory in a programmable manner upon physically tapping the skin. Our rubbery synaptic transistor and neurologically integrated devices pave the way toward enabled neurological functions in soft machines and other applications.

A Barcoded Polymer-Based Cross-Reactive Spectroscopic Sensor Array for Organic Volatiles

The development of cross-reactive sensor arrays for volatile organics (electronic noses, e-noses) is an active area of research. In this manuscript, we present a new format for barcoded polymer sensor arrays based on porous polymer beads. An array of nine self-encoded polymers was analyzed by Raman spectroscopy before and after exposure to a series of volatile organic compounds, and the changes in the vibrational fingerprints of their polymers was recorded before and after exposure. Our results show that the spectroscopic changes experienced by the porous spectroscopically encoded beads after exposure to an analyte can be used to identify and classify the target analytes. To expedite this analysis, analyte-specific changes induced in the sensor arrays were transformed into a response pattern using multivariate data analysis. These studies established the barcoded bead array format as a potentially effective sensing element in e-nose devices. Devices such as these have the potential to advance personalized medicine, providing a platform for non-invasive, real-time volatile metabolite detection.

A novel real-time PCR assay panel for detection of common respiratory pathogens in a convenient, strip-tube array format

Commercial multiplex assays, built on different chemistries and platforms are widely available for simultaneous detection of pathogens that cause respiratory infections. However, these tests are often difficult to implement in a resource limited setting because of high cost. In this study, we developed and validated a method for simultaneous testing of common respiratory pathogens (Respanel) by real-time PCR in a convenient, strip-tube array format. Primers and probes for sixteen PCR assays were selected from the literature or newly designed. Following optimization of individual PCR assays, strip-tube arrays were prepared by dispensing primer-probe mixes (PPM) into two sets of 8-tube strips. Nucleic acid extracts from specimens were mixed with PCR master mix, and dispensed column-wise into 2X8-wells of a 96-well plate. PPMs from strip-tubes were then added to the wells using a multichannel pipette for real-time PCR. Individual PCR assays were optimized using previously known specimens (n=397) with 91%-100% concordance with culture, DFA or PCR results. Respanel was then tested in a routine manner at two different sites using specimens (n=147) previously tested by Qiagen Resplex I&II or Fast-Track Diagnostics Respiratory Pathogens 21 assays. The sensitivity, specificity and accuracy of Respanel were 94%, 95% and 95%, respectively, against Resplex and 88%, 100% and 99%, respectively, against FTDRP21. Respanel detected 48% more pathogens (p<0.05) than Resplex but the rate of pathogen detection was not significantly different from FTDRP21. Respanel is a convenient and inexpensive assay that is more sensitive than Resplex and comparable to FTDRP21 for the detection of common respiratory pathogens.