ReContrast: Domain-Specific Anomaly Detection via Contrastive Reconstruction

Most advanced unsupervised anomaly detection (UAD) methods rely on modeling feature representations of frozen encoder networks pre-trained on large-scale datasets, e.g. ImageNet. However, the features extracted from the encoders that are borrowed from natural image domains coincide little with the features required in the target UAD domain, such as industrial inspection and medical imaging. In this paper, we propose a novel epistemic UAD method, namely ReContrast, which optimizes the entire network to reduce biases towards the pre-trained image domain and orients the network in the target domain. We start with a feature reconstruction approach that detects anomalies from errors. Essentially, the elements of contrastive learning are elegantly embedded in feature reconstruction to prevent the network from training instability, pattern collapse, and identical shortcut, while simultaneously optimizing both the encoder and decoder on the target domain. To demonstrate our transfer ability on various image domains, we conduct extensive experiments across two popular industrial defect detection benchmarks and three medical image UAD tasks, which shows our superiority over current state-of-the-art methods.Comment: NeurIPS 2023 Poste

Retina-Inspired Organic Heterojunction-Based Optoelectronic Synapses for Artificial Visual Systems

For the realization of retina-inspired neuromorphic visual systems which simulate basic functions of human visual systems, optoelectronic synapses capable of combining perceiving, processing, and memorizing in a single device have attracted immense interests. Here, optoelectronic synaptic transistors based on tris(2-phenylpyridine) iridium (Ir(ppy)3) and poly(3,3-didodecylquarterthiophene) (PQT-12) heterojunction structure are presented. The organic heterojunction serves as a basis for distinctive synaptic characteristics under different wavelengths of light. Furthermore, synaptic transistor arrays are fabricated to demonstrate their optical perception efficiency and color recognition capability under multiple illuminating conditions. The wavelength-tunability of synaptic behaviors further enables the mimicry of mood-modulated visual learning and memorizing processes of humans. More significantly, the computational dynamics of neurons of synaptic outputs including associated learning and optical logic functions can be successfully demonstrated on the presented devices. This work may locate the stage for future studies on optoelectronic synaptic devices toward the implementation of artificial visual systems

TAT‐LBD‐Ngn2‐improved cognitive functions after global cerebral ischemia by enhancing neurogenesis

Abstract Background Stroke is the major cause of adult neurocognitive disorders (NCDs), and presents a significant burden on both of the families and society. To improve the cerebral injury, we generated a blood–brain barrier penetrating peptide TAT‐LBD‐Ngn2, in which Ngn2 (Neurogenin2) is a classical preneural gene that enhances neurogenesis, and neural precursor cells survival and differentiation. We previously demonstrated that it has a short‐term protective effect against cerebral ischemia‐reperfusion injury. However, it is uncertain if TAT‐LBD‐Ngn2 could promote neurogenesis to exhibit long‐term therapeutic impact. Methods and results In present study, TAT‐LBD‐Ngn2 was administered for 14 or 28 days following bilateral common carotid arteries occlusion (BCCAO). After confirming that TAT‐LBD‐Ngn2 could cross the brain blood barrier and aggregate in the hippocampus, we conducted open field test, Morris water maze and contextual fear conditioning to examine the long‐term effect of TAT‐LBD‐Ngn2 on cognition. We discovered that TAT‐LBD‐Ngn2 significantly improved the spatial and contextual learning and memory on both days 14 and 28 after BCCAO, while TAT‐LBD‐Ngn2 exhibited anxiolytic effect only on day 14, but had no effect on locomotion. Using western blot and immunofluorescence, TAT‐LBD‐Ngn2 was also shown to promote neurogenesis, as evidenced by increased BrdU+ and DCX+ neurons in dentate gyrus. Meanwhile, TAT‐LBD‐Ngn2 elevated the expression of brain derived neurotrophic factor rather than nerve growth factor compared to the control group. Conclusions Our findings revealed that TAT‐LBD‐Ngn2 could dramatically promote learning and memory in long term by facilitating neurogenesis in the hippocampus after global cerebral ischemia, indicating that TAT‐LBD‐Ngn2 may be an appealing candidate for treating poststroke NCD

Fat Mass and Obesity-Associated (FTO) Gene Polymorphisms Are Associated with Physical Activity, Food Intake, Eating Behaviors, Psychological Health, and Modeled Change in Body Mass Index in Overweight/Obese Caucasian Adults

The fat mass and obesity-associated (FTO) gene is currently recognized as the most robust predictor of polygenic obesity. We investigated associations between the FTO rs1421085 and rs17817449 polymorphisms and the FTO rs1421085–rs17817449 haplotype and dietary intake, eating behavior, physical activity, and psychological health, as well as the effect of these associations on BMI. N = 133 treatment seeking overweight/obese Caucasian adults participated in this study. Genotyping was performed from whole blood samples. Weight and height was measured and a non-quantified food frequency questionnaire was completed to assess food group intake. Validated questionnaires were completed to assess physical activity (Baecke questionnaire), psychological health (General Health questionnaire, Rosenburg self-esteem scale and Beck Depression Inventory), and eating behavior (Three Factor Eating questionnaire). The risk alleles of the FTO polymorphisms were associated with poorer eating behaviors (higher hunger, internal locus for hunger, and emotional disinhibition scores), a higher intake of high fat foods and refined starches and more depressive symptoms. The modeled results indicate that interactions between the FTO polymorphisms or haplotypes and eating behavior, psychological health, and physical activity levels may be associated with BMI. The clinical significance of these results for implementation as part of weight management interventions needs further investigation