4,360 research outputs found
Emergent localized states at the interface of a twofold -symmetric lattice
We consider the role of non-triviality resulting from a non-Hermitian
Hamiltonian that conserves twofold PT-symmetry assembled by interconnections
between a PT-symmetric lattice and its time reversal partner. Twofold
PT-symmetry in the lattice produces additional surface exceptional points that
play the role of new critical points, along with the bulk exceptional point. We
show that there are two distinct regimes possessing symmetry-protected
localized states, of which localization lengths are robust against external
gain and loss. The states are demonstrated by numerical calculation of a
quasi-1D ladder lattice and a 2D bilayered square lattice.Comment: 10 pages, 7 figure
Dietary, Metabolic, and Potentially Environmental Modulation of the Lysine Acetylation Machinery
Healthy lifestyles and environment produce a good state of health. A number of scientific studies support the notion that external stimuli regulate an individual's epigenomic profile. Epigenetic changes play a key role in defining gene expression patterns under both normal and pathological conditions. As a major posttranslational modification, lysine (K) acetylation has received much attention, owing largely to its significant effects on chromatin dynamics and other cellular processes across species. Lysine acetyltransferases and deacetylases, two opposing families of enzymes governing K-acetylation, have been intimately linked to cancer and other diseases. These enzymes have been pursued by vigorous efforts for therapeutic development in the past 15 years or so. Interestingly, certain dietary components have been found to modulate acetylation levels in vivo. Here we review dietary, metabolic, and environmental modulators of the K-acetylation machinery and discuss how they may be of potential value in the context of disease prevention
Comparison of supercritical and near-critical carbon dioxide extraction of carotenoid enriched wheat bran oil
Supercritical and near-critical carbon dioxide (CO2) extraction were carried out to extract oil from wheat bran. The extraction temperatures for supercritical and near-critical CO2 were 35 - 45°C and 25 - 30°C, respectively. The applied pressure was ranging from 10 to 30 MPa for both supercritical and near-critical CO2 extraction. The extraction was performed in a semi batch process with a CO2 flow rate of 26.81 g/min for 1.5 h. The oil obtained from wheat bran at different extraction conditions was quantitatively measured to investigate the solubility of oil at supercritical and near-critical CO2. The highest solubility was found at near-critical condition. The fatty acid compositions of wheat bran oil were measured by gas chromatography (GC). Linoleic, palmitic, oleic and γ-linolenic acid were the major fatty acids of wheat bran oil. Total carotenoid was measured spectrophotometerically. Highest yield of total carotenoid was found at 45°C and 30 MPa.Key words: Supercritical and near-critical carbon dioxide, wheat bran oil, total carotenoid
Feature Re-calibration based Multiple Instance Learning for Whole Slide Image Classification
Whole slide image (WSI) classification is a fundamental task for the
diagnosis and treatment of diseases; but, curation of accurate labels is
time-consuming and limits the application of fully-supervised methods. To
address this, multiple instance learning (MIL) is a popular method that poses
classification as a weakly supervised learning task with slide-level labels
only. While current MIL methods apply variants of the attention mechanism to
re-weight instance features with stronger models, scant attention is paid to
the properties of the data distribution. In this work, we propose to
re-calibrate the distribution of a WSI bag (instances) by using the statistics
of the max-instance (critical) feature. We assume that in binary MIL, positive
bags have larger feature magnitudes than negatives, thus we can enforce the
model to maximize the discrepancy between bags with a metric feature loss that
models positive bags as out-of-distribution. To achieve this, unlike existing
MIL methods that use single-batch training modes, we propose balanced-batch
sampling to effectively use the feature loss i.e., (+/-) bags simultaneously.
Further, we employ a position encoding module (PEM) to model
spatial/morphological information, and perform pooling by multi-head
self-attention (PSMA) with a Transformer encoder. Experimental results on
existing benchmark datasets show our approach is effective and improves over
state-of-the-art MIL methods.Comment: MICCAI 202
Deleterious effects in reproduction and developmental immunity elicited by pulmonary iron oxide nanoparticles
With the extensive application of iron oxide nanoparticles (FeNPs), attention about their potential risks to human health is also rapidly raising, particularly in sensitive subgroups such as pregnant women and babies. In this study, we a single instilled intratracheally FeNPs (1, 2, and 4 mg/kg) to the male and female parent mice, mated, then assessed reproductive toxicity according to the modified OECD TG 421. During the pre-mating period (14 days), two female parent mice died at 4 mg/kg dose, and the body weight gain dose-dependently decreased in male and female parent mice exposed to FeNPs. Additionally, iron accumulation and the enhanced expression of MHC class II molecules were observed in the ovary and the testis of parent mice exposed to the highest dose of FeNPs, and the total sex ratio (male/female) of the offspring mice increased in the groups exposed to FeNPs. Following, we a single instilled intratracheally to their offspring mice with the same doses and evaluated the immunotoxic response on day 28. The increased mortality and significant hematological- and biochemical- changes were observed in offspring mice exposed at 4 mg/kg dose, especially in female mice. More interestingly, balance of the immune response was shifted to a different direction in male and female offspring mice. Taken together, we conclude that the NOAEL for reproductive and developmental toxicity of FeNPs may be lower than 2 mg/kg, and that female mice may show more sensitive response to FeNPs exposure than male mice. Furthermore, we suggest that further studies are necessary to identify causes of both the alteration in sex ratio of offspring mice and different immune response in male and female offspring mice.
- …