Relationship between histopathological changes in SC and histopathological changes in intrascleral vessels in primary open-angle glaucoma

The purpose of this study was to investigate morphological changes in the outflow pathway from Schlemm’s canal (SC) to the intrascleral vessels (ISVs) in POAG eyes through comparisons with age-matched, normal control eyes using light microscopy and morphometric analysis. We hypothesized that there would be a reduction in the size and number of ISVs when SC becomes narrower and collapsed in the eyes with POAG and there would be no reduction in size and number of ISVs when SC is open in eyes with POAG. 11 normal eyes from 10 donors (63-92 years old) without a history of ocular diseases and 10 POAG eyes from 6 donors (67-90 years old) with clinically confirmed diagnoses of POAG were acquired. The eyes were fixed and embedded. The sections of anterior chamber angle (2-3 μm in thickness) were cut, stained with sectioning procedures, and imaged using a light microscope. 36 images from 11 normal eyes and 40 images from 10 glaucomatous eyes were examined and analyzed in this study. Cross-sectional area (CSA), width, height of SC and percentage collapse of SC as well as the number and CSA of ISVs were measured within each quadrant of the eye. Statistical analyses were conducted using one-way ANOVA and Kruskal-Wallis test in the IBM SPSS software. A significant reduction in height, width, and CSA of SC, and a significant increase in percentage of SC collapse were found in 70% of POAG eyes, while open SC was found in 30% of POAG eyes when compared to normal eyes. Decreased sizes and number of ISVs were observed in 70% of POAG eyes with narrower and collapsed SC, but these changes did not reach statistical significance. Decreased sizes of ISVs were observed in 30% of POAG eyes with open SC, although these changes did not reach statistical significance. The results suggested that smaller and collapsed SC was found in 70% of eyes with POAG. Ultimately, the decreased size and number of ISVs found in POAG eyes may be secondary to decreased size and collapse of SC in POAG pathology

Multidimensional Approaches to Examining Digital Literacies in the Contemporary Global Society

Literacy scholars have offered compelling theories about and methods for understanding the digital literacy practices of youth. However, little work has explored the possibility of an approach that would demonstrate how different perspectives on literacies might intersect and interconnect in order to better describe the multifaceted nature of youth digital literacies. In this conceptual article, we adopt the idea of theoretical triangulation in interpretive inquiry and explore how multiple perspectives can jointly contribute to constructing a nuanced description of young people’s literacies in today’s digitally mediated global world. For this purpose, we first suggest a triangulation framework that integrates sociocultural, affective, and cognitive perspectives on digital literacies, focusing on recent developments in these perspectives. We then use an example of discourse data from a globally connected online affinity space and demonstrate how our multidimensional framework can lead to a complex analysis and interpretation of the data. In particular, we describe the substance of one specific case of youth digital literacies from each of the three perspectives on literacy, which in turn converge to provide a complex account of such literacy practices. In conclusion, we discuss the promise and limitations of our integrative approach to studying the digital literacy practices of youth

Knowledge Unlearning for Mitigating Privacy Risks in Language Models

Pretrained Language Models (LMs) memorize a vast amount of knowledge during initial pretraining, including information that may violate the privacy of personal lives and identities. Previous work addressing privacy issues for language models has mostly focused on data preprocessing and differential privacy methods, both requiring re-training the underlying LM. We propose knowledge unlearning as an alternative method to reduce privacy risks for LMs post hoc. We show that simply applying the unlikelihood training objective to target token sequences is effective at forgetting them with little to no degradation of general language modeling performances; it sometimes even substantially improves the underlying LM with just a few iterations. We also find that sequential unlearning is better than trying to unlearn all the data at once and that unlearning is highly dependent on which kind of data (domain) is forgotten. By showing comparisons with a previous data preprocessing method known to mitigate privacy risks for LMs, we show that unlearning can give a stronger empirical privacy guarantee in scenarios where the data vulnerable to extraction attacks are known a priori while being orders of magnitude more computationally efficient. We release the code and dataset needed to replicate our results at https://github.com/joeljang/knowledge-unlearning

Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way

Recent spectroscopic observations of the outer halo globular cluster (GC) NGC 2419 show that it is unique among GCs, in terms of chemical abundance patterns, and some suggest that it was originated in the nucleus of a dwarf galaxy. Here we show, from the Subaru narrow-band photometry employing a calcium filter, that the red giant-branch (RGB) of this GC is split into two distinct subpopulations. Comparison with spectroscopy has confirmed that the redder RGB stars in the $hk$[=(Ca$-b)-(b-y)$] index are enhanced in [Ca/H] by $\sim$0.2 dex compared to the bluer RGB stars. Our population model further indicates that the calcium-rich second generation stars are also enhanced in helium abundance by a large amount ($\Delta$Y = 0.19). Our photometry, together with the results for other massive GCs (e.g., $\omega$ Cen, M22, and NGC 1851), suggests that the discrete distribution of RGB stars in the $hk$ index might be a universal characteristic of this growing group of peculiar GCs. The planned narrow-band calcium photometry for the Local Group dwarf galaxies would help to establish an empirical connection between these GCs and the primordial building blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ

A Microfluidic System for Stable and Continuous EEG Monitoring from Multiple Larval Zebrafish

Along with the increasing popularity of larval zebrafish as an experimental animal in the fields of drug screening, neuroscience, genetics, and developmental biology, the need for tools to deal with multiple larvae has emerged. Microfluidic channels have been employed to handle multiple larvae simultaneously, even for sensing electroencephalogram (EEG). In this study, we developed a microfluidic chip capable of uniform and continuous drug infusion across all microfluidic channels during EEG recording. Owing to the modular design of the microfluidic channels, the number of animals under investigation can be easily increased. Using the optimized design of the microfluidic chip, liquids could be exchanged uniformly across all channels without physically affecting the larvae contained in the channels, which assured a stable environment maintained all the time during EEG recording, by eliminating environmental artifacts and leaving only biological effects to be seen. To demonstrate the usefulness of the developed system in drug screening, we continuously measured EEG from four larvae without and with pentylenetetrazole application, up to 60 min. In addition, we recorded EEG from valproic acid (VPA)-treated zebrafish and demonstrated the suppression of seizure by VPA. The developed microfluidic system could contribute to the mass screening of EEG for drug development to treat neurological disorders such as epilepsy in a short time, owing to its handy size, cheap fabrication cost, and the guaranteed uniform drug infusion across all channels with no environmentally induced artifacts. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.1

A 3D flexible neural interface based on a microfluidic interconnection cable capable of chemical delivery

The demand for multifunctional neural interfaces has grown due to the need to provide a better understanding of biological mechanisms related to neurological diseases and neural networks. Direct intracerebral drug injection using microfluidic neural interfaces is an effective way to deliver drugs to the brain, and it expands the utility of drugs by bypassing the blood–brain barrier (BBB). In addition, uses of implantable neural interfacing devices have been challenging due to inevitable acute and chronic tissue responses around the electrodes, pointing to a critical issue still to be overcome. Although neural interfaces comprised of a collection of microneedles in an array have been used for various applications, it has been challenging to integrate microfluidic channels with them due to their characteristic three-dimensional structures, which differ from two-dimensionally fabricated shank-type neural probes. Here we present a method to provide such three-dimensional needle-type arrays with chemical delivery functionality. We fabricated a microfluidic interconnection cable (µFIC) and integrated it with a flexible penetrating microelectrode array (FPMA) that has a 3-dimensional structure comprised of silicon microneedle electrodes supported by a flexible array base. We successfully demonstrated chemical delivery through the developed device by recording neural signals acutely from in vivo brains before and after KCl injection. This suggests the potential of the developed microfluidic neural interface to contribute to neuroscience research by providing simultaneous signal recording and chemical delivery capabilities. © 2021, The Author(s).1

Multiple Stellar Populations outside the tidal radius of NGC1851 through Gaia DR3 XP Spectra

Ancient Galactic Globular Clusters (GCs) have long fascinated astronomers due to their intriguing multiple stellar populations characterized by variations in light-element abundances. Among these clusters, Type-II GCs stand out as they exhibit stars with large differences in heavy-element chemical abundances. These enigmatic clusters, comprising approximately 17\% of analyzed GCs with MPs, have been hypothesized to be the remnants of accreted dwarf galaxies. We focus on one of the most debated Type~II GCs, NGC1851, to investigate its MPs across a wide spatial range of up to 50 arcmin from the cluster center. By using Gaia DR3 low-resolution XP spectra, we generate synthetic photometry to perform a comprehensive analysis of the spatial distribution and kinematics of the canonical and anomalous populations within this GC. By using appropriate CMDs from the synthetic photometry in the BVI bands and in the $\rm f415^{25}$ band introduced in this work, we identify distinct stellar sequences associated with different heavy-element chemical composition. Our results suggest that the canonical and the anomalous populations reside both inside and outside the tidal radius of NGC1851, up to a distance that exceeds by 3.5 times its tidal radius. However, $\sim$80\% of stars outside the tidal radius are consistent with belonging to the canonical population, emphasizing its dominance in the cluster's outer regions. Remarkably, canonical stars exhibit a more circular on-sky morphology, while the anomalous population displays an elliptical shape. Furthermore, we delve into the kinematics of the multiple populations. Our results reveal a flat/increasing velocity dispersion profile in the outer regions and hints of a tangentially anisotropic motion in the outer regions, indicating a preference for stars to escape on radial orbits.Comment: 13 pages, 10 figures, accepted for publication in A&