285 research outputs found
Effects of Temperature on the Proliferation of Human and Fish Lens Epithelial Cells
Crystallins are proteins that confer refractive properties to the crystalline lens. All vertebrate lenses contain α- and β-crystallins, and often a third major crystallin. Crystallins can have additional non-refractive functions; α-crystallins act as heat shock proteins, protecting lenses from heat-induced denaturation, and γ-crystallins are thought to be cryoproteins, protecting lenses from extreme cold. The concentration of α-crystallins is higher in mammalian lenses than in teleost lenses, while the opposite is true for γ-crystallins, suggesting that mammalian lenses would be better protected in warmer conditions and teleost lenses better protected in colder temperatures. This study determined whether temperature affects the growth of lens epithelial cells (LECs) derived from human and fish lenses. Both human and rainbow trout fish LECs were cultured (n = 4 each) and grown for 1, 2, 4, 6, 8 and 12 days at the optimal (37°C and 18°C, respectively), higher than optimal (42°C and 25°C, respectively) and lower than optimal temperatures (32°C and 10°C, respectively). At optimal temperatures, both fish and human LECs grew optimally. Higher temperatures were more deleterious to the proliferation index than lower temperatures for both human and fish LECs. Mitotic cells were non-existent in fish LECs grown at high temperatures. The sizes of the cells did not greatly change with temperature with either species, but human cells at non-optimal temperature tended to clump over time. Human LECs at the optimal temperature maintained their random distribution. Fish LECs at optimal temperatures moved from a random distribution to a clumped distribution, but lower temperatures had the opposite effect; LECs moved from a clumped to a random distribution. Only the high temperature group of fish LECs maintain their random organisation
Human Health Indicator Prediction from Gait Video
Body Mass Index (BMI), age, height and weight are important indicators of
human health conditions, which can provide useful information for plenty of
practical purposes, such as health care, monitoring and re-identification. Most
existing methods of health indicator prediction mainly use front-view body or
face images. These inputs are hard to be obtained in daily life and often lead
to the lack of robustness for the models, considering their strict requirements
on view and pose. In this paper, we propose to employ gait videos to predict
health indicators, which are more prevalent in surveillance and home monitoring
scenarios. However, the study of health indicator prediction from gait videos
using deep learning was hindered due to the small amount of open-sourced data.
To address this issue, we analyse the similarity and relationship between pose
estimation and health indicator prediction tasks, and then propose a paradigm
enabling deep learning for small health indicator datasets by pre-training on
the pose estimation task. Furthermore, to better suit the health indicator
prediction task, we bring forward Global-Local Aware aNd Centrosymmetric
Encoder (GLANCE) module. It first extracts local and global features by
progressive convolutions and then fuses multi-level features by a
centrosymmetric double-path hourglass structure in two different ways.
Experiments demonstrate that the proposed paradigm achieves state-of-the-art
results for predicting health indicators on MoVi, and that the GLANCE module is
also beneficial for pose estimation on 3DPW
Preliminary Study on Functional and Aesthetic Reconstruction by Using a Small Artery-only Free Medial Flap of the Second Toe for Fingertip Injuries
OBJECTIVES: This study was designed to introduce the feasibility of fingertip reconstruction by using a free medial flap of the second toe without vein anastomosis. METHODS: In total, 8 patients with fingertip injuries were treated successfully with this method. Patients who underwent reconstruction from September 2016 to October 2017 in our hospital with an artery-only free medial flap transfer of the second toe for fingertip injuries were included, and patients who underwent additional procedures that may impact the postoperative results and were followed up for less than 6 months were excluded. Clinical trial registration: ChiCTR19000021883. RESULTS: According to the Allen classification, five patients had Type 3 injuries, and three patients had Type 4 injuries. One arterial nerve and one digital nerve were repaired at the same time. No additional dissection was performed in either the donor or recipient site of the dorsal or volar vein. Postoperative venous congestion was monitored based on the color, temperature and the degree of tissue oxygen saturation. The flap size ranged from 1.20*1.0 cm2 to 1.80*1.0 cm2 . The reconstruction time was 71.86 (SD 14.75) minutes. The two-point discrimination and the monofilament results were satisfying; cold intolerance did not appear in five patients, and the other three patients had cold intolerance with grades of 4, 12 and 26, which were considered satisfactory. Moreover, leech therapy, continuous bleeding and needle sutures were not utilized in any cases. CONCLUSIONS: Reconstruction with a small artery-only free medial flap transfer of the second toe led to satisfactory sensory and motor function in the selected patients with fingertip injuries
Data Poisoning Attacks Against Multimodal Encoders
Traditional machine learning (ML) models usually rely on large-scale labeled
datasets to achieve strong performance. However, such labeled datasets are
often challenging and expensive to obtain. Also, the predefined categories
limit the model's ability to generalize to other visual concepts as additional
labeled data is required. On the contrary, the newly emerged multimodal model,
which contains both visual and linguistic modalities, learns the concept of
images from the raw text. It is a promising way to solve the above problems as
it can use easy-to-collect image-text pairs to construct the training dataset
and the raw texts contain almost unlimited categories according to their
semantics. However, learning from a large-scale unlabeled dataset also exposes
the model to the risk of potential poisoning attacks, whereby the adversary
aims to perturb the model's training dataset to trigger malicious behaviors in
it. Previous work mainly focuses on the visual modality. In this paper, we
instead focus on answering two questions: (1) Is the linguistic modality also
vulnerable to poisoning attacks? and (2) Which modality is most vulnerable? To
answer the two questions, we conduct three types of poisoning attacks against
CLIP, the most representative multimodal contrastive learning framework.
Extensive evaluations on different datasets and model architectures show that
all three attacks can perform well on the linguistic modality with only a
relatively low poisoning rate and limited epochs. Also, we observe that the
poisoning effect differs between different modalities, i.e., with lower MinRank
in the visual modality and with higher Hit@K when K is small in the linguistic
modality. To mitigate the attacks, we propose both pre-training and
post-training defenses. We empirically show that both defenses can
significantly reduce the attack performance while preserving the model's
utility
- …