Abstract: Ultra near-field index modulated plasmonic nano-aperture label-free imaging methods and techniques are useful for imaging and detection of biological microparticles and nanoparticles such as circulating tumor exosomes (CTEs), bacteria and vimses. The methods and techniques utilize a high-density array of gold, silver, or gold/silver alloy nanodisks, in some cases on an undercut or invisible substrate. Given the relatively large nanodisk dimensions, the nanodisk array may feature a significantly blue-shifted LSPR extinction peak due to both far-field plasmonic coupling and substrate undercut. The ultra near-field imaging methods have the ability to image nanoparticles as small as 25 nm.

Abstract: This disclosure relates to the use of Matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) to assay tissue samples. Methods of analyzing a tissue sample may generally comprise generating sample ions directly from the tissue sample using a MALDI ionization source, receiving the ions into a mass spectrometer, identifying at least one esophageal tumor related compound in the sample from results from the mass spectrometer, comparing the at least one identified esophageal tumor related compound in the sample to one or more known esophageal tumor profiles, and identifying at least one condition related to the sample from the comparison of the at least one identified esophageal tumor related compound to the one or more known esophageal tumor profiles. The mass spectrometer may be a quadrupole mass spectrometer, a time of flight mass spectrometer, an Orbitrap mass spectrometer, or an ion trap mass spectrometer.

Abstract: An integrated, optoelectronic, variable thresholding neuron implemented monolithically in a GaAs integrated circuit and exhibiting high differential optical gain and low power consumption. Two alternative embodiments each comprise an LED monolithically integrated with a detector and two transistors. One of the transistors is responsive to a bias voltage applied to its gate for varying the threshold of the neuron. One embodiment is implemented as an LED monolithically integrated with a double heterojunction bipolar phototransistor (detector) and two metal semiconductor field-effect transistors (MESFET's) on a single GaAs substrate and another embodiment is implemented as an LED monolithically integrated with three MESFET's (one of which is an optical FET detector) on a single GaAs substrate. The first noted embodiment exhibits a differential optical gain of 6 and an optical switching energy of 10 pJ. The second embodiment has a differential optical gain of 80 and an optical switching energy or 38 pJ.

Abstract: High-gain MOCVD-grown (metal-organic chemical vapor deposition) AlGaAs/GaAs/AlGaAs n-p-n double heterojunction bipolar transistors (DHBTs) (14) and Darlington phototransistor pairs (14, 16) are provided for use in optical neural networks and other optoelectronic integrated circuit applications. The reduced base (22) doping level used herein results in effective blockage of Zn out-diffusion, enabling a current gain of 500, higher than most previously reported values for Zn-diffused-base DHBTs. Darlington phototransistor pairs of this material can achieve a current gain of over 6,000, which satisfies the gain requirement for optical neural network designs, which advantageously may employ novel neurons (10) comprising the Darlington phototransistor pair in series with a light source (12).