BPKD: Boundary Privileged Knowledge Distillation For Semantic Segmentation

Current knowledge distillation approaches in semantic segmentation tend to adopt a holistic approach that treats all spatial locations equally. However, for dense prediction, students' predictions on edge regions are highly uncertain due to contextual information leakage, requiring higher spatial sensitivity knowledge than the body regions. To address this challenge, this paper proposes a novel approach called boundary-privileged knowledge distillation (BPKD). BPKD distills the knowledge of the teacher model's body and edges separately to the compact student model. Specifically, we employ two distinct loss functions: (i) edge loss, which aims to distinguish between ambiguous classes at the pixel level in edge regions; (ii) body loss, which utilizes shape constraints and selectively attends to the inner-semantic regions. Our experiments demonstrate that the proposed BPKD method provides extensive refinements and aggregation for edge and body regions. Additionally, the method achieves state-of-the-art distillation performance for semantic segmentation on three popular benchmark datasets, highlighting its effectiveness and generalization ability. BPKD shows consistent improvements across a diverse array of lightweight segmentation structures, including both CNNs and transformers, underscoring its architecture-agnostic adaptability. The code is available at \url{https://github.com/AkideLiu/BPKD}.Comment: 17 pages, 9 figures, 9 table

Bone-Targeted Mesoporous Silica Nanocarrier Anchored by Zoledronate for Cancer Bone Metastasis

Once bone metastasis occurs, the chances of survival and quality of life for cancer patients decrease significantly. With the development of nanomedicine, nanocarriers loading bisphosphonates have been built to prevent cancer metastasis based on their enhanced permeability and retention (EPR) effects; however, as a passive mechanism, the EPR effects cannot apply to the metastatic sites because of their lack of leaky vasculature. In this study, we fabricated 40 nm-sized mesoporous silica nanoparticles (MSNs) anchored by zoledronic acid (ZOL) for targeting bone sites and delivered the antitumor drug doxorubicin (DOX) in a spatiotemporally controlled manner. The DOX loading and release behaviors, bone-targeting ability, cellular uptake and its mechanisms, subcellular localization, cytotoxicity, and the antimigration effect of this drug delivery system (DDS) were investigated. The results indicated that MSNs–ZOL had better bone-targeting ability compared with that of the nontargeted MSNs. The maximum loading capacity of DOX into MSNs and MSNs–ZOL was about 1671 and 1547 mg/g, with a loading efficiency of 83.56 and 77.34%, respectively. DOX@MSNs–ZOL had obvious pH-sensitive DOX release behavior. DOX@MSNs–ZOL entered into cells through an ATP-dependent pathway and then localized in the lysosome to achieve effective intracellular DOX release. The antitumor results indicated that DOX@MSNs–ZOL exhibited the best cytotoxicity against A549 cells and significantly decreased cell migration in vitro. This DDS is promising for the treatment of cancer bone metastasis in the future

Defect-Related Luminescent Mesoporous Silica Nanoparticles Employed for Novel Detectable Nanocarrier

Uniform and well-dispersed walnut kernel-like mesoporous silica nanoparticles (MSNs) with diameters about 100 nm have been synthesized by a templating sol–gel route. After an annealing process, the as-obtained sample (DLMSNs) inherits the well-defined morphology and good dispersion of MSNs, and exhibits bright white-blue luminescence, higher specific surface area and pore volume, and better biocompatibility. The drug loading and release profiles show that DLMSNs have high drug loading capacity, and exhibit an initial burst release followed by a slow sustained release process. Interestingly, the luminescence intensity of the DLMSNs-DOX system increases gradually with the increase of cumulative released DOX, which can be verified by the confocal laser scanning images. The drug carrier DLMSNs can potentially be applied as a luminescent probe for monitoring the drug release process. Moreover, the DLMSNs-DOX system exhibits potent anticancer effect against three kinds of cancer cells (HeLa, MCF-7, and A549 cells)

Up-Conversion Y₂O₃:Yb³⁺,Er³⁺ Hollow Spherical Drug Carrier with Improved Degradability for Cancer Treatment

The rare earth hollow spheres with up-conversion luminescence properties have shown potential applications in drug delivery and bioimaging fields. However, there have been few reports for the degradation properties of rare earth oxide drug carriers. Herein, uniform and well-dispersed Y₂O₃:Yb³⁺,Er³⁺ hollow spheres (YOHSs) have been fabricated by a general Pechini sol–gel process with melamine formaldehyde colloidal spheres as template. The novel YOHSs with up-conversion luminescence has good drug loading amount and drug-release efficiency; moreover, it exhibits pH-responsive release patterns. In particular, the YOHSs sample exhibits low cytotoxicity and excellent degradable properties in acid buffer. After the sample was loaded with anticancer drug doxorubicin (DOX), the antitumor result <i>in vitro</i> indicates that YOHS-DOX might be effective in cancer treatment. The animal imaging test also reveals that the YOHSs drug carrier can be used as an outstanding luminescent probe for bioimaging <i>in vivo</i> application prospects. The results suggest that the degradable drug carrier with up-conversion luminescence may enhance the delivery efficiency of drugs and improve the cancer therapy in clinical applications