•A novel sparse representation method for pedestrian trajectory abnormal analysis.•Utilizing Lp-regularization (0 < p < 1) to get sparser solutions.•An effective solver for the proposed method with ...EM algorithm and entropy.
Pedestrian abnormal trajectory understanding based on video surveillance systems can improve public safety. However, manually identifying pedestrian abnormal trajectories is usually a prohibitive workload. The objective of this study is to propose an automatic method for understanding pedestrian abnormal trajectories. An improved sparse representation model, namely information entropy constrained trajectory representation method (IECTR), is developed for pedestrian trajectory classification. It aims to reduce the entropy for trajectory representation and to obtain superior analyzing results. In the proposed method, the orthogonal matching pursuit (OMP) is embedded in the expectation maximization (EM) method to iteratively obtain the selection probabilities and the sparse coefficients. In addition, the lower-bound sparser condition of Lp-minimization (0 < p < 1) is applied in the proposed method to guarantee salient solutions. In order to validate the performance and effectiveness of the proposed method, classification experiments are conducted using five pedestrian trajectory datasets. The results show that the identification accuracy of the proposed method is superior to the compared methods, including naïve Bayes classifier (NBC), support vector machine (SVM), k-nearest neighbor (kNN), and typical sparse representation-based methods.
Because of limited access to global positioning system (GPS) signals, accurate and reliable localization for intelligent vehicles in underground parking lots is still an open problem. This paper ...proposes a multi-view and multi-scale localization method aiming at solving this problem. The proposed method is divided into an offline mapping stage and an online localization stage. In the mapping stage, the offline map is generated by fusing 3-D information, WiFi features, visual features, and trajectory from visual odometry (VO). In the localization stage, WiFi fingerprint matching is exploited for coarse localization. Based on the result of coarse localization, multi-view localization is exploited for image-level localization. Finally, metric localization is exploited to refine the localization results. By applying this multi-scale strategy, it is possible to fuse WiFi localization and visual localization and reduce the image matching and error rate to a great extent. Because of exploiting more information, multi-view localization is more robust and accurate than single-view localization. The method is tested in a 2,000 m2 underground parking lot. The result demonstrates that this method can achieve sub-meter localization on average. The proposed localization method can be a supplement to the existing intelligent vehicle localization techniques.
Place recognition matches a corresponding image from a pre-built image sequence, and it plays an important role in visual map-based vehicle localisation. This study proposes a Bayesian place ...recognition (BPR) algorithm based on a bag of objects (BoO). The proposed BoO is superior to the classic bag of words (BoW), with a faster speed and greater robustness for scene representation. Like BoW, BoO uses object probabilities computed from the pre-trained AlexNet to construct a histogram-like vector called the BoO feature. A small portion of objects, named dominant objects, are computed from map data to reduce the storage requirement. The BoO feature is used to describe the scene image similarity. Owing to the excellent recognition performance of AlexNet, the BoO feature is robust to dynamic illumination environments. With BoO, the BPR model is employed to fuse appearance feature and motion clue for place recognition. Moreover, a multi-scale localisation strategy is developed to improve the place recognition efficiency. The proposed method was tested with the collected data and the KITTI datasets. The method achieved 0.37 frame errors, taking an average of 4.7 ms for place recognition. Experimental results demonstrated that the proposed method outperforms the classic BoW and binary BoW.
A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging（SPRi） and image processing.In this device,a gravity-induced flow injection chip（gFIC） was ...exploited to replace a pump.Also two charge coupled devices（CCDs） were used to detect HepG2 cells by SPRi and image processing,respectively.The results of two CCDs are associated.Protein A was used to modify the sensing surface.The inlet angle was carefully adjusted for the device to get an enhanced image.In the test,the contrast among cell solutions at different concentrations can be easily distinguished.The other CCD using image processing can tell false-positive in some degree.This detection is label-free,real time,and precise.
•Hybrid antibacterial agent was developed based on silver nanoparticles and curcumin.•Silver nanoparticles were synthesized using oxidized amylose as reducing agent.•Solubility of curcumin was ...increased by encapsulating into oxidized amylose.•The hybrid antibacterial agent exhibited enhanced antibacterial activity.•The hybrid presented good antioxidant activity and cell compatibility.
Many kinds of multi-drug-resistant microorganisms have appeared. Moreover, monotherapy is increasingly no longer adequate for many complicated bacterial infections. Therefore, development of efficient combination antibacterial agent is becoming crucial. Herein, we present a hybrid antibacterial agent with enhanced antibacterial activity and high aqueous dissolubility based on silver nanoparticles and curcumin. The silver nanoparticles were firstly synthesized using oxidized amylose as an environmentally friendly reducing agent and stabilizer. Then, curcumin was added into the above mixture to get the hybrid antibacterial agent. The hybrid antibacterial agent presented high dissolubility in aqueous solution and enhanced antibacterial activity. In addition, the hybrid antibacterial agent presented good antioxidant activity and cell compatibility. Overall, the developed hybrid antibacterial agent has a potential to combat multiple bacteria-induced infections of wound surfaces.
Herein, the functions of a N dopant in crystalline MoS2 catalysts during the electrochemical hydrogen evolution reaction (HER) were reported via a combined experimental and first-principles approach. ...However, studies on the N doping of amorphous MoSx, which is a more active catalyst, have not been reported to date. In this study, via a simple method, we fabricated N-doped amorphous MoSx for the first time and studied the correlations between the N dopant and the HER performance. Via X-ray photoelectron spectroscopy and theoretical formation energy calculations, we have found that a N dopant in basal plane S2− plays a very important role in the improvement of the HER performance and remains stable during this dynamic transformation process. A N dopant in basal plane S2− can increase the number of active sites toward the HER and enhance the conductivity of the catalysts as well as a N dopant in c-MoS2. In addition to this, the first-principles calculations further suggested that a N dopant in basal plane S2− could improve the activity of unsaturated MoV active sites by bringing its hydrogen adsorption free energy closer to zero. As a result, N-doped amorphous MoSx possesses an overpotential of 143 mV at 10 mA cm−2 and a Tafel slope of 57 mV dec−1, much better than those of a-MoSx. These results provide useful insights for the future development of nonmetal-doped MoSx catalysts in the HER.
•Antibacterial wound dressing was prepared using collagen, oxidized amylose and linalool.•Oxidized amylose was used as carrier to introduce linalool into collagen matrix.•The wound dressing had ...excellent antibacterial activity as expected.•The wound dressing had good blood compatibility and cell biocompatibility.•The wound dressing could prevent inflammation and accelerate wound healing.
This study aimed to prepare antibacterial wound dressings based on collagen and linalool/oxidized amylose inclusion complex. Encapsulation with oxidized amylose was used as an effective way to introduce linalool into collagen matrix. Our results showed that the content of linalool in the composite dressings was efficiently increased thanks to the solubilization effect of oxidized amyloses. The developed composite dressings possessed porous structure. They had abilities to keep the wound in moist environment and meanwhile prevent the excess exudates accumulation. The incorporation of linalool conferred the composite dressings with excellent antibacterial activities as expected. Moreover, the composite dressing with the highest content of linalool presented enhanced blood compatibility and good cell biocompatibility. This composite dressing effectively promoted granulation tissue formation and accelerated wound healing. It effectively prevented inflammation in regenerated skin tissue and scar formation too. Overall, the developed antibacterial wound dressings hold great potential for use in wound healing applications.
Under the FI/PTI guidance, CADCR nanoparticles could cut off glycolysis, angiogenesis, TCA cycle, and glutamine metabolism in tumor cells simultaneously, and further induced cell ketoacidosis and ...apoptosis. Therefore, CADCR NPs are expected to provide an effective strategy to simultaneously achieve severe starvation, reinforce PTT and CDT, and activate immunotherapy towards tumor cells, which exhibits great potential for clinical cancer therapy.
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Single cancer starvation therapy (ST) strategy can’t achieve satisfactory anti-tumor effect, mainly due to the diversified nutritional sources of tumor cells. Herein, CuS@Axitinib-SiO2@2-Deoxy-D-glucose(2-DG)-CaCO3-RGD nanoparticles (CADCR NPs) were prepared for three-pathway blocking for efficient starvation therapy as well as reinforced photothermal therapy (PTT) and chemodynamic therapy (CDT). After CADCR NPs were targeted to tumor cells, CaCO3 was ruptured in the acidic environment, releasing Ca2+ to chelate glutamine and cutting off the glutamine metabolic pathway of the tumor. 2-DG was also released from mesoporous SiO2 and restrained the glycolytic pathway of tumor cells. In addition, under the thermal stimulus of near-infrared irradiation, axitinib was released from CuS NPs, which inhibited the proliferation of tumor blood vessels, ultimately inhibiting the aerobic respiratory pathway of tumor cells. Interestingly, CADCR NPs also showed potential to reshape the tumor microenvironment (TME) and promoted the transformation of macrophages from M2 to M1 type, increasing the expression of CD8+ T cells in the tumor site. In conclusion, CADCR NPs achieve severe tumor starvation by simultaneously interfering with three energy metabolic pathways, and further enhance tumor treatment with the aid of PTT, CDT, and TME improvement, which exhibits great potential for clinical cancer therapy.
Herein, the functions of a N dopant in crystalline MoS2 catalysts during the electrochemical hydrogen evolution reaction (HER) were reported via a combined experimental and first-principles approach. ...However, studies on the N doping of amorphous MoSx, which is a more active catalyst, have not been reported to date. In this study, via a simple method, we fabricated N-doped amorphous MoSx for the first time and studied the correlations between the N dopant and the HER performance. Via X-ray photoelectron spectroscopy and theoretical formation energy calculations, we have found that a N dopant in basal plane S2- plays a very important role in the improvement of the HER performance and remains stable during this dynamic transformation process. A N dopant in basal plane S2- can increase the number of active sites toward the HER and enhance the conductivity of the catalysts as well as a N dopant in c-MoS2. In addition to this, the first-principles calculations further suggested that a N dopant in basal plane S2- could improve the activity of unsaturated MoV active sites by bringing its hydrogen adsorption free energy closer to zero. As a result, N-doped amorphous MoSx possesses an overpotential of 143 mV at 10 mA cm-2 and a Tafel slope of 57 mV dec-1, much better than those of a-MoSx. These results provide useful insights for the future development of nonmetal-doped MoSx catalysts in the HER.
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