Publications by authors named "Nicholas Huang"

Introduction: Though marijuana use has been linked to an increase in heart failure admissions, no prior study has explored the association between its use and outcomes after coronary artery bypass grafting (CABG). This study examines the relationship between marijuana use and postoperative outcomes in CABG patients.

Methods: We utilized data from the National Inpatient Sample database from 2008 to 2018 for CABG patients ≥18 y old.

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Continuous clinical grade measurement of SpO in out-of-hospital settings remains a challenge despite the widespread use of photoplethysmography (PPG) based wearable devices for health and wellness applications. This article presents two SpO algorithms: PRR (pulse rate derived ratio-of-ratios) and GPDR (green-assisted peak detection ratio-of-ratios), that utilize unique pulse rate frequency estimations to isolate the pulsatile (AC) component of red and infrared PPG signals and derive SpO measurements. The performance of the proposed SpO algorithms are evaluated using an upper-arm wearable device derived green, red, and infrared PPG signals, recorded in both controlled laboratory settings involving healthy subjects (n=36) and an uncontrolled clinic application involving COVID-19 patients (n=52).

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Photoplethysmography (PPG) and accelerometer (ACC) are commonly integrated into wearable devices for continuous unobtrusive pulse rate and activity monitoring of individuals during daily life. However, obtaining continuous and clinically accurate respiratory rate measurements using such wearable sensors remains a challenge. This article presents a novel algorithm for estimation of respiration rate (RR) using an upper-arm worn wearable device by deriving multiple respiratory surrogate signals from PPG and ACC sensing.

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Salience is the quality of a sensory signal that attracts involuntary attention in humans. While it primarily reflects conspicuous physical attributes of a scene, our understanding of processes underlying what makes a certain object or event salient remains limited. In the vision literature, experimental results, theoretical accounts, and large amounts of eye-tracking data using rich stimuli have shed light on some of the underpinnings of visual salience in the brain.

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Human insulin () gene diverged from the ancestral genes of invertebrate and mammalian species millions of years ago. We previously found that mouse insulin gene () isoforms are expressed in brain choroid plexus (ChP) epithelium cells, where insulin secretion is regulated by serotonin and not by glucose. We further compared human isoform expression in postmortem ChP and islets of Langerhans.

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Recent advances in wearable devices with optical Photoplethysmography (PPG) and actigraphy have enabled inexpensive, accessible, and convenient Heart Rate (HR) monitoring. Nevertheless, PPG's susceptibility to motion presents challenges in obtaining reliable and accurate HR estimates during ambulatory and intense activity conditions. This study proposes a lightweight HR algorithm, TAPIR: a Time-domain based method involving Adaptive filtering, Peak detection, Interval tracking, and Refinement, using simultaneously acquired PPG and accelerometer signals.

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In everyday social environments, demands on attentional resources dynamically shift to balance our attention to targets of interest while alerting us to important objects in our surrounds. The current study uses electroencephalography to explore how the push-pull interaction between top-down and bottom-up attention manifests itself in dynamic auditory scenes. Using natural soundscapes as distractors while subjects attend to a controlled rhythmic sound sequence, we find that salient events in background scenes significantly suppress phase-locking and gamma responses to the attended sequence, countering enhancement effects observed for attended targets.

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The choroid plexus (ChP) is a highly vascularized tissue found in the brain ventricles, with an apical epithelial cell layer surrounding fenestrated capillaries. It is responsible for the production of most of the cerebrospinal fluid (CSF) in the ventricular system, subarachnoid space, and central canal of the spinal cord, while also constituting the blood-CSF barrier (BCSFB). In addition, epithelial cells of the ChP (EChP) synthesize neurotrophic factors and other signaling molecules that are released into the CSF.

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Targeting peripheral CB1R is desirable for the treatment of metabolic syndromes without adverse neuropsychiatric effects. We previously reported a human hCB1b isoform that is selectively enriched in pancreatic beta-cells and hepatocytes, providing a potential peripheral therapeutic hCB1R target. It is unknown whether there are peripherally enriched mouse and rat CB1R (mCB1 and rCB1, respectively) isoforms.

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Deep neural networks have been recently shown to capture intricate information transformation of signals from the sensory profiles to semantic representations that facilitate recognition or discrimination of complex stimuli. In this vein, convolutional neural networks (CNNs) have been used very successfully in image and audio classification. Designed to imitate the hierarchical structure of the nervous system, CNNs reflect activation with increasing degrees of complexity that transform the incoming signal onto object-level representations.

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Corticotropin-releasing hormone-binding protein (CRH-BP) is a secreted glycoprotein that binds CRH with very high affinity to modulate CRH receptor activity. CRH-BP is widely expressed throughout the brain, with particularly high expression in regions such as the amygdala, hippocampus, ventral tegmental area and prefrontal cortex (PFC). Recent studies suggest a role for CRH-BP in stress-related psychiatric disorders and addiction, with the PFC being a potential site of interest.

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Salience describes the phenomenon by which an object stands out from a scene. While its underlying processes are extensively studied in vision, mechanisms of auditory salience remain largely unknown. Previous studies have used well-controlled auditory scenes to shed light on some of the acoustic attributes that drive the salience of sound events.

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Genomic DNA (gDNA) contamination of RNA samples can lead to inaccurate measurement of gene expression by reverse transcription quantitative real-time PCR (RT-qPCR). We describe an easily adoptable PCR-based method where gDNA contamination in RNA samples is assessed by comparing the amplification of intronic and exonic sequences from a housekeeping gene. Although this alternative assay was developed for rat RNA samples, it could be easily adapted to other species.

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Establishing neural determinants of psychophysical performance requires both behavioral and neurophysiological metrics amenable to correlative analyses. It is often assumed that organisms use neural information optimally, such that any information available in a neural code that could improve behavioral performance is used. Studies have shown that detection of amplitude-modulated (AM) auditory tones by humans is correlated to neural synchrony thresholds, as recorded in rabbit at the level of the inferior colliculus, the first level of the ascending auditory pathway where neurons are tuned to AM stimuli.

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Sorting action potentials (spikes) from tetrode recordings can be time consuming, labor intensive, and inconsistent, depending on the methods used and the experience of the operator. The techniques presented here were designed to address these issues. A feature related to the slope of the spike during repolarization is computed.

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