Humans can naturally and effectively find salient regions in complex scenes. Motivated by this observation, attention mechanisms were introduced into computer vision with the aim of imitating this ...aspect of the human visual system. Such an attention mechanism can be regarded as a dynamic weight adjustment process based on features of the input image. Attention mechanisms have achieved great success in many visual tasks, including image classification, object detection, semantic segmentation, video understanding, image generation, 3D vision, multimodal tasks, and self-supervised learning. In this survey, we provide a comprehensive review of various attention mechanisms in computer vision and categorize them according to approach, such as channel attention, spatial attention, temporal attention, and branch attention; a related repository
https://github.com/MenghaoGuo/Awesome-Vision-Attentions
is dedicated to collecting related work. We also suggest future directions for attention mechanism research.
Enhanced drug delivery can improve the therapeutic efficacy of drugs and help overcome side effects. However, many reported drug‐delivery systems are too complex and irreproducible for practical use. ...In this work, the design of a hypoxia‐responsive molecular container based on calixarene, called CAC4A, which presents a significant advance in practical, hypoxia‐targeted drug‐delivery, is reported. CAC4A enables a wide variety of clinical drugs to be quantitatively loaded to improve their solubility and stability, as well as enable the administration of reduced doses. Furthermore, as a result of its azo functional groups, which are sensitive to reduction within a hypoxic environment, it is possible to achieve tumor‐targeted drug‐release with reduced side effects. CAC4A fulfils all essential requirements for a drug‐delivery system in addition to multiple advantages, including facile preparation, well‐defined molecular weight, and structure, and universal applicability. Such features collectively enable supramolecular prodrugs to be formulated simply and reproducibly, with potential for bench‐to‐bedside translation. Moreover, CAC4A is amenable to other therapy modalities and can be facilely decorated with functional groups and hybridized with nanomaterials, providing ample possibilities for its role in future drug‐delivery systems.
Carboxylated azocalix4arene is designed as a hypoxia‐responsive molecular container, which affords strong binding toward a series of chemotherapeutic drugs, and improves the drugs’ solubility and stability, demonstrating its universality as a supramolecular drug carrier. Taking one supramolecular prodrug as an example, the efficacy of this hypoxia‐targeted therapy is validated in vitro and in vivo.
The most critical attribute of human language is its unbounded combinatorial nature: smaller elements can be combined into larger structures on the basis of a grammatical system, resulting in a ...hierarchy of linguistic units, such as words, phrases and sentences. Mentally parsing and representing such structures, however, poses challenges for speech comprehension. In speech, hierarchical linguistic structures do not have boundaries that are clearly defined by acoustic cues and must therefore be internally and incrementally constructed during comprehension. We found that, during listening to connected speech, cortical activity of different timescales concurrently tracked the time course of abstract linguistic structures at different hierarchical levels, such as words, phrases and sentences. Notably, the neural tracking of hierarchical linguistic structures was dissociated from the encoding of acoustic cues and from the predictability of incoming words. Our results indicate that a hierarchy of neural processing timescales underlies grammar-based internal construction of hierarchical linguistic structure.
The first catalytic hydrocarboxylation of enamides and imines with CO2 to generate valuable α,α‐disubstituted α‐amino acids is reported. Notably, excellent chemo‐ and regio‐selectivity are achieved, ...significantly different from previous reports on β‐carboxylation of enamides, homocoupling or reduction of imines. Moreover, this transition‐metal‐free procedure exhibits low loading of an inexpensive catalyst, easily available substrates, mild reaction conditions, high efficiency, facile scalability and easy product derivatization, providing great potential for application in organic synthesis, pharmaceutical chemistry, and biochemistry.
Catalytic hydrocarboxylation of easily available enamides and imines with one atmosphere of CO2 is realized to generate valuable α,α‐disubstituted α‐amino acids under mild reaction conditions. Notably, excellent chemo‐ and regioselectivity are achieved, significantly different from previous reports. 4CzIPN=1,2,3,5‐Tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene.
In this paper, the perturbed resonant nonlinear Schrödinger equation with dual-power law nonlinearity describing the pulse phenomena in nonlinear optics is investigated. By utilizing the complete ...discrimination system for polynomial method and the trial equation method, a variety of exact solutions of this equation have been acquired, including rational solutions, triangular function periodic solutions, solitary wave solutions, elliptic function double periodic solutions, as well as the corresponding nonlinear chirps. Besides, several representative two-dimensional graphs are plotted at specific parameters, which can supply a more comprehensive physical interpretation of the complex nonlinear model based on the intuitive identification of the morphology of optical waves.
In this paper, the improved nonlinear Schrödinger equation with dual-power law nonlinearity and Hamiltonian perturbation terms describing the dynamics of ultrashort pulse propagation in nano optical ...fibers is researched. Numerous exact solutions and corresponding nonlinear chirps of this equation are received by using the complete discrimination system for polynomial method and direct integral method. And several emblematic two-dimensional graphs are drawn under specific parameters, which can identify the morphology of optical waves more intuitively.
Combination therapy based on molecular drugs and therapeutic genes provides an effective strategy for malignant tumor treatment. However, effective gene and drug combinations for cancer treatment are ...limited by the widespread antagonism between therapeutic genes and molecular drugs. Herein, a calixarene‐embedded nanoparticle (CENP) is developed to co‐deliver molecular drugs and therapeutic genes without compromising their biological functions, thereby achieving interference‐free gene–drug combination cancer therapy. CENP is composed of a cationic polyplex core and an acid‐responsive polymer shell, allowing CENP loading and delivering therapeutic genes with improved circulation stability and enhanced tumor accumulation. Moreover, the introduction of carboxylated azocalix4arene, which is a hypoxia‐responsive calixarene derivatives, in the polyplex core endows CENP with the capability to load molecular drugs through the host–guest complexation as well as inhibit the interference between the drugs and genes by encapsulating the drugs into its cavity. By loading doxorubicin and a plasmid DNA‐based CRISPR interference system that targets miR‐21, CENP exhibits the significantly enhanced anti‐tumor effects in mice. Considering the wide variety of calixarene derivatives, CENP can be adapted to deliver almost any combination of drugs and genes, providing the potential as a universal platform for the development of interference‐free gene–drug combination cancer therapy.
In this study, a calixarene‐embedded nanoparticle (CENP) is reported as a universal nanoplatform that can co‐delivermolecular drugs and therapeutic geneswithout compromising their biological functions, thereby achieving interference free gene–drug combination cancer therapy. By loading doxorubicin and a CRISPR interference system that targets miR‐21, CENP exhibits the significantly enhanced anti‐tumor effects in mice.
The electrochemical sensing is a potential method for detection of trace toxic substance. Herein, the heterojunction of netlike ZnO/BiOCl nanosheets was constructed for the enhanced electrochemical ...detection of ammonia. Cyclic voltammetry and linear sweep voltammetry were used to investigate the electrochemical performance. The results show that the ZnO/BiOCl‐modified electrode exhibits higher sensitivity towards ammonia compared with the ZnO and BiOCl‐based electrodes, which is ascribed to band structure and fast electron transfer. The high response of 11.8 μA mM−1 and a low detection limit (LOD) of 0.25 μM are achieved. In addition, the ZnO/BiOCl material exhibits high selectivity, repeatability and stability. The better linear relationship between concentration and current (R2=0.99) is significant for quantitative detection of ammonia, implying that netlike ZnO/BiOCl nanosheets can serve as electrochemical sensing platform for detecting toxic substance. This research provides a strategy for fabricating two‐dimensional netlike materials and regulating heterojunctions used for electrochemical application.
ZnO/BiOCl heterojunction material is fabricated by constructing netlike ZnO and BiOCl nanosheets. It exhibits high selectivity to ammonia and detection limit is 0.25 μM, which is suitable to detect volatile amines quantitatively. The synergetic effects of the heterojunction and netlike structures contribute to boosting electrochemical activity. The ZnO/BiOCl hybrid could be an promising candidate for detection and analysis.
A rapid, sensitive, and efficient ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method has been developed to analyze polymethoxylated ...flavonoids (PMFs) in 14 Citrus peels, including 7 Citrus reticulata (C. reticulata) and 7 Citrus sinensis (C. sinensis). In this study, fast separation can be achieved within 12 min and 42 PMFs have been identified including 33 flavones and 9 flavanones. Most C. reticulata were shown to contain more than 20 PMFs, except Guangxihongpisuanju (GX) containing only 12 PMFs, while most C. sinensis contained fewer than 20 PMFs, except Edangan (EG) containing as many as 32 PMFs. To our knowledge, there are few reports about the quantitation of PMFs using the MS response. Here, a MS quantitative method was established and systematically validated in linearity, precision, and recovery. The linearity was from 1.25 ng/mL to 1.0 μg/mL with the limit of detection (LOD) as low as 75 pg/mL and the limit of quantitation (LOQ) as low as 0.25 ng/mL. Up to 13 PMFs, more types than ever before, were undoubtedly identified and quantitated according to the PMF standards. The results showed that the contents of PMFs in the C. reticulata were generally higher than those in the C. sinensis. This study is systematic for analyzing PMFs and is of great significance because it can provide guidance on utilization of both PMFs and citrus germplasm resources in the future.
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