335 research outputs found
Harnack Inequality for Distribution Dependent Stochastic Hamiltonian System
The dimension free Harnack inequality is established for the distribution
dependent stochastic Hamiltonian system, where the drift is Lipschitz
continuous in the measure variable under the distance induced by the
H\"{o}lder-Dini continuous functions, which are -H\"{o}lder continuous on the degenerate component and
square root of Dini continuous on the non-degenerate one. The results extend
the existing ones in which the drift is Lipschitz continuous in the measure
variable under -Wasserstein distance.Comment: 23 page
Perceptual MAE for Image Manipulation Localization: A High-level Vision Learner Focusing on Low-level Features
Nowadays, multimedia forensics faces unprecedented challenges due to the
rapid advancement of multimedia generation technology thereby making Image
Manipulation Localization (IML) crucial in the pursuit of truth. The key to IML
lies in revealing the artifacts or inconsistencies between the tampered and
authentic areas, which are evident under pixel-level features. Consequently,
existing studies treat IML as a low-level vision task, focusing on allocating
tampered masks by crafting pixel-level features such as image RGB noises, edge
signals, or high-frequency features. However, in practice, tampering commonly
occurs at the object level, and different classes of objects have varying
likelihoods of becoming targets of tampering. Therefore, object semantics are
also vital in identifying the tampered areas in addition to pixel-level
features. This necessitates IML models to carry out a semantic understanding of
the entire image. In this paper, we reformulate the IML task as a high-level
vision task that greatly benefits from low-level features. Based on such an
interpretation, we propose a method to enhance the Masked Autoencoder (MAE) by
incorporating high-resolution inputs and a perceptual loss supervision module,
which is termed Perceptual MAE (PMAE). While MAE has demonstrated an impressive
understanding of object semantics, PMAE can also compensate for low-level
semantics with our proposed enhancements. Evidenced by extensive experiments,
this paradigm effectively unites the low-level and high-level features of the
IML task and outperforms state-of-the-art tampering localization methods on all
five publicly available datasets
IML-ViT: Benchmarking Image Manipulation Localization by Vision Transformer
Advanced image tampering techniques are increasingly challenging the
trustworthiness of multimedia, leading to the development of Image Manipulation
Localization (IML). But what makes a good IML model? The answer lies in the way
to capture artifacts. Exploiting artifacts requires the model to extract
non-semantic discrepancies between manipulated and authentic regions,
necessitating explicit comparisons between the two areas. With the
self-attention mechanism, naturally, the Transformer should be a better
candidate to capture artifacts. However, due to limited datasets, there is
currently no pure ViT-based approach for IML to serve as a benchmark, and CNNs
dominate the entire task. Nevertheless, CNNs suffer from weak long-range and
non-semantic modeling. To bridge this gap, based on the fact that artifacts are
sensitive to image resolution, amplified under multi-scale features, and
massive at the manipulation border, we formulate the answer to the former
question as building a ViT with high-resolution capacity, multi-scale feature
extraction capability, and manipulation edge supervision that could converge
with a small amount of data. We term this simple but effective ViT paradigm
IML-ViT, which has significant potential to become a new benchmark for IML.
Extensive experiments on five benchmark datasets verified our model outperforms
the state-of-the-art manipulation localization methods.Code and models are
available at \url{https://github.com/SunnyHaze/IML-ViT}
Cell responses to two kinds of nanohydroxyapatite with different sizes and crystallinities
Xiaochen Liu1, Minzhi Zhao1, Jingxiong Lu2, Jian Ma4, Jie Wei2, Shicheng Wei1,31Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 2Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, 3Department of Oral and Maxillofacial Surgery, School of Stomatology, Peking University, Beijing, 4Hospital of Stomatology, Tongji University, Shanghai, ChinaIntroduction:Hydroxyapatite (HA) is the principal inorganic constituent of human bone. Due to its good biocompatibility and osteoconductivity, all kinds of HA particles were prepared by different methods. Numerous reports demonstrated that the properties of HA affected its biological effects.Methods: Two kinds of nanohydroxyapatite with different sizes and crystallinities were obtained via a hydrothermal treatment method under different temperatures. It was found that at a temperature of 140°C, a rod-like crystal (n-HA1) with a diameter of 23 ± 5 nm, a length of 47 ± 14 nm, and crystallinity of 85% ± 5% was produced, while at a temperature of 80°C, a rod-like crystal (n-HA2) with a diameter of 16 ± 3 nm, a length of 40 ± 10 nm, and crystallinity of 65% ± 3% was produced. The influence of nanohydroxyapatite size and crystallinity on osteoblast viability was studied by MTT, scanning electron microscopy, and flow cytometry.Results: n-HA1 gave a better biological response than n-HA2 in promoting cell growth and inhibiting cell apoptosis, and also exhibited much more active cell morphology. Alkaline phosphatase activity for both n-HA2 and n-HA1 was obviously higher than for the control, and no significant difference was found between n-HA1 and n-HA2. The same trend was observed on Western blotting for expression of type I collagen and osteopontin. In addition, it was found by transmission electron microscopy that large quantities of n-HA2 entered into the cell and damaged the cellular morphology. Release of tumor necrosis factor alpha from n-HA2 was markedly higher than from n-HA1, indicating that n-HA2 might trigger a severe inflammatory response.Conclusion: This work indicates that not all nanohydroxyapatite should be considered a good biomaterial in future clinical applications.Keywords: nanohydroxyapatite, osteoblast-like cells, cell viability, cell differentiatio
Nano-TiO2/PEEK bioactive composite as a bone substitute material: in vitro and in vivo studies
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Urban-rural disparity in prevalence of multimorbidity in China: a cross-sectional nationally representative study.
BACKGROUND: To address the neglect of depression in multimorbidity measurement and the lack of focus on rural population in previous literature about China, this paper aimed to estimate the prevalence of multimorbidity (including depressive disorders) among the country's rural and urban population. METHODS: We used a cross-sectional design and data from a nationally representative survey conducted in 2015-2016 among Chinese people aged 45 years or older involving 19 656 participants. Multimorbidity was measured with a cut-off point of having two or more among 14 chronic illnesses. In that 13 of them were based on self-reported physician diagnosis. In addition, depressive disorders were assessed with the 10-item Centre for Epidemiologic Studies Depression Scale. The weighted prevalence of multimorbidity was calculated, with a non-response adjustment. Multivariate logistic regression was applied to analyse the relation between covariates and multimorbidity. FINDINGS: Multimorbidity was highly prevalent (54.3%) among the studied population. Contrary to previous studies, we found the prevalence of multimorbidity to be higher among the rural dwellers (58.3%) than among the urban population (50.4%). After adjustment for covariates, rural residents had 7.5% higher odds (95% CI of OR (1.003 to 1.151)) of having multimorbidity than their urban counterparts. Above 70% of patients with any of the 14 chronic illnesses above 45 years old had multimorbidity, while 80.6%-97.9% of chronic patients had multimorbidity. INTERPRETATION: Future health system development in China should transform from preventing and controlling non-communicable diseases as individual diseases to addressing people's comprehensive health needs under multimorbidity. The rural population should be prioritised as they suffered more from multimorbidity than the urban population
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