Synthetic biology based on bacteria has been displayed in antitumor therapy and shown good performance. In this study, an engineered bacterium Escherichia coli MG1655 is designed with NDH‐2 enzyme ...(respiratory chain enzyme II) overexpression (Ec‐pE), which can colonize in tumor regions and increase localized H2O2 generation. Following from this, magnetic Fe3O4 nanoparticles are covalently linked to bacteria to act as a catalyst for a Fenton‐like reaction, which converts H2O2 to toxic hydroxyl radicals (•OH) for tumor therapy. In this constructed bioreactor, the Fenton‐like reaction occurs with sustainably synthesized H2O2 produced by engineered bacteria, and severe tumor apoptosis is induced via the produced toxic •OH. These results show that this bioreactor can achieve effective tumor colonization, and realize a self‐supplied therapeutic Fenton‐like reaction without additional H2O2 provision.
A Fenton‐like bioreactor based on bacteria is reported for tumor therapy without exogenous H2O2 provision. It is found that this bioreactor can achieve effective tumor colonization, and realize a self‐supplied therapeutic Fenton‐like reaction without additional H2O2 provision.
A new chitosan biosorbent modified with zirconium ions (ZCB) was prepared and employed for the adsorption of phosphate ions from aqueous solution. Batch of experiments were performed to investigate ...the effects of various conditions on the phosphate adsorption, including contact time, the initial concentration of phosphate ions, temperature and pH. The experimental data were interpreted elaborately by the different models of adsorption kinetics and isotherms. The results showed that the kinetic data were well fitted to the pseudo first-order and second-order models, indicating that the adsorption behaviors were mainly ascribed to both physic-sorption and chemic-sorption. The further analysis of kinetics indicated that the intra-particle diffusion was the rate controlling process. The equilibrium data were best described by the Langmuir isotherm model with maximum monolayer adsorption capacity of 60.6mgg−1. The values of △G°, △S° and △H° revealed that the nature of adsorption was feasible, spontaneous and endothermic. FTIR, EDS, XPS and zeta potential studies suggested that the adsorption mechanism was possibly attributed to the electrostatic attraction and ion exchange reaction between ZCB and phosphate ions.
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•Chitosan beads modified with zirconium (ZCB) were prepared and used for P sorption.•Various models and isotherms were employed to describe the adsorption process.•Isoelectric points of ZCB and ZCB-P kept the same charge at pH of 3.5.•Mechanism for P adsorption was electrostatic attraction and ion exchange reaction.
Sentiment analysis is one of the important tasks of online opinion analysis and an important means to guide the direction of online opinion and maintain social stability. Due to the multiple ...characteristics of linguistic expressions, ambiguity, multiple meanings of words, and the increasing speed of new words, it is a great challenge for the task of text sentiment analysis. Commonly used machine learning methods suffer from inadequate text feature extraction, and the emergence of deep learning has brought a turnaround for this purpose. In this paper, we investigate the problem of text sentiment analysis using methods related to deep learning. In order to incorporate user and product information in a more diverse way in the model, this paper proposes a model based on a deep bidirectional long-and short-term memory network-self-attention mechanism-custom classifier. The model first identifies contextual associations and acquires deep text features through a deep bidirectional long- and short-term memory network and then captures important features in the text using a self-attentive mechanism. The model finally combines user information and product information to build a custom classifier module and uses context-aware attention mechanisms to assign specific parameters to user information and product information, which improves the performance of the model on public datasets compared with current common models. The results show that the accuracy of the algorithm in this paper is high, and it is about 5% lower than the traditional algorithm. The method can reduce the number of iterations and the running time of the algorithm.
The traditional dance training process lacks a certain degree of scientificity due to the lack of precise motion capture and analysis system, which directly affects the final training effect. In view ...of the robust limitations of the type 1 fuzzy reinforcement learning flexible structure control system to the uncertainty of noise interference, based on the reinforcement learning algorithm, this paper proposes a flexible structure controller based on the type 2 fuzzy reinforcement learning algorithm. Moreover, this paper uses fuzzy sets with equidistant fuzzy centers to divide large-scale state or continuous state space into two types of fuzzy divisions, divide the action space uniformly, and build fuzzy rules based on the basic ideas of type 1 fuzzy reinforcement learning. In addition, this paper constructs an evaluation system for factors affecting dance training effects based on reinforcement learning and designs experiments to verify the performance of the system. The research results show that the system constructed in this paper meets the theoretical needs and can be applied to dance training practice later.
Recently, various soft universal grippers have been developed due to their reduced control complexity and satisfying grasping capability. The gripping range of a gripper plays a key role in its ...universality. This article presents a pneumatically actuated soft-rigid hybrid multifinger gripper that has a wide gripping range by adjusting its initial grasp postures. The gripper is compact (dimensions: <inline-formula><tex-math notation="LaTeX">\text{100} \times \text{60} \times \text{170}</tex-math></inline-formula> mm), lightweight (weight: 380 g), and modular. It consists of four modules, with each module containing three pneumatic actuators (a distance-adjusting actuator, an angle-adjusting actuator, and a finger actuator) and rigid connectors. Through initial grasp posture adjustment, and fingers with tapered angles to generate nonconstant bending while grasping, the gripper can grasp objects of a wide variety of sizes and weights, thus increasing its universality. The gripper is tested to characterize its distance adjustment range, angle adjustment range, and stiffnesses in load-bearing directions, at continuously changing pneumatic pressures. The distance adjustment range and angle adjustment range of the gripper are 0-64.4 mm (64.4% of the initial gripper length) and 0<inline-formula><tex-math notation="LaTeX">^{\circ}</tex-math></inline-formula>-140<inline-formula><tex-math notation="LaTeX">^{\circ}</tex-math></inline-formula>, respectively. The maximum stiffnesses of distance-adjusting actuator and angle-adjusting actuator are 3331 and 1.15 N<inline-formula><tex-math notation="LaTeX">\cdot</tex-math></inline-formula>m/rad, respectively. Finally, grasping experiments show that our gripper can successfully grasp objects with diameters ranging from 0.5 to 180 mm, lengths ranging from 10 to 325 mm, and the heaviest object it can grasp is 2.1 kg (more than five folds of its own weight). The results demonstrated that our pneumatic gripper has an increased gripping range without adding other types of energy sources and its enhanced universality will expedite various applications in daily life and industry.
The intermolecular asymmetric radical oxidative C(sp3)−C(sp) cross‐coupling of C(sp3)−H bonds with readily available terminal alkynes is a promising method to forge chiral C(sp3)−C(sp) bonds because ...of the high atom and step economy, but remains underexplored. Here, we report a copper‐catalyzed asymmetric C(sp3)−C(sp) cross‐coupling of (hetero)benzylic and (cyclic)allylic C−H bonds with terminal alkynes that occurs with high to excellent enantioselectivity. Critical to the success is the rational design of chiral oxazoline‐derived N,N,P(O)‐ligands that not only tolerate the strong oxidative conditions which are requisite for intermolecular hydrogen atom ion (HAA) processes but also induce the challenging enantiocontrol. Direct access to a range of synthetically useful chiral benzylic alkynes and 1,4‐enynes, high site‐selectivity among similar C(sp3)−H bonds, and facile synthesis of enantioenriched medicinally relevant compounds make this approach very attractive.
Chiral benzylic alkynes and 1,4‐enynes can be obtained in a straightforward approach from commercially available terminal alkynes and a diverse range of compounds containing benzylic and allylic C−H bonds by using the title reaction. The success of this approach lies in newly designed anionic N,N,P(O)‐ligands bearing a stable chiral oxazoline and a pentavalent phosphine oxide that are generated in situ.
A photothermal bacterium (PTB) is reported for tumor‐targeted photothermal therapy (PTT) by using facultative anaerobic bacterium Shewanella oneidensis MR‐1 (S. oneidensis MR‐1) to biomineralize ...palladium nanoparticles (Pd NPs) on its surface without affecting bacterial activity. It is found that PTB possesses superior photothermal property in near infrared (NIR) regions, as well as preferential tumor‐targeting capacity. Zeolitic imidazole frameworks‐90 (ZIF‐90) encapsulating photosensitizer methylene blue (MB) are hybridized on the surface of living PTB to further enhance PTT efficacy. MB‐encapsulated ZIF‐90 (ZIF‐90/MB) can selectively release MB at mitochondria and cause mitochondrial dysfunction by producing singlet oxygen (1O2) under light illumination. Mitochondrial dysfunction further contributes to adenosine triphosphate (ATP) synthesis inhibition and heat shock proteins (HSPs) down‐regulated expression. The PTB‐based therapeutic platform of PTB@ZIF‐90/MB demonstrated here will find great potential to overcome the challenges of tumor targeting and tumor heat tolerance in PTT.
A bacteria‐based photothermal therapeutic platform comprising PTB@ZIF‐90/MB is developed, which reveals great potential to augment photothermal therapy efficacy by tackling the challenges of tumor targeting and heat resistance.
In contrast to the wealth of asymmetric transformations for generating central chirality from alkyl radicals, the enantiocontrol over the allenyl radicals for forging axial chirality represents an ...uncharted domain. The challenge arises from the unique elongated linear configuration of the allenyl radicals that necessitates the stereo‐differentiation of remote motifs away from the radical reaction site. We herein describe a copper‐catalyzed asymmetric radical 1,4‐carboalkynylation of 1,3‐enynes via the coupling of allenyl radicals with terminal alkynes, providing diverse synthetically challenging tetrasubstituted chiral allenes. A chiral N,N,P‐ligand is crucial for both the reaction initiation and the enantiocontrol over the highly reactive allenyl radicals. The reaction features a broad substrate scope, covering a variety of (hetero)aryl and alkyl alkynes and 1,3‐enynes as well as radical precursors with excellent functional group tolerance.
A copper‐catalyzed asymmetric radical 1,4‐carboalkynylation of 1,3‐enynes is realized, providing diverse tetrasubstituted chiral allenes. The utilization of the copper/chiral N,N,P‐ligand is crucial for the enantiocontrol over the allenyl radicals, which is difficult due to their elongated linear configuration that necessitates the stereo‐differentiation of remote motifs away from the reaction site.
Advances in high-throughput sequencing (HTS) have fostered rapid developments in the field of microbiome research, and massive microbiome datasets are now being generated. However, the diversity of ...software tools and the complexity of analysis pipelines make it difficult to access this field. Here, we systematically summarize the advantages and limitations of microbiome methods. Then, we recommend specific pipelines for amplicon and metagenomic analyses, and describe commonly-used software and databases, to help researchers select the appropriate tools. Furthermore, we introduce statistical and visualization methods suitable for microbiome analysis, including alpha- and betadiversity, taxonomic composition, difference comparisons, correlation, networks, machine learning, evolution, source tracing, and common visualization styles to help researchers make informed choices. Finally, a stepby-step reproducible analysis guide is introduced. We hope this review will allow researchers to carry out data analysis more effectively and to quickly select the appropriate tools in order to efficiently mine the biological significance behind the data.
Radical‐involved enantioselective oxidative C−H bond functionalization by a hydrogen‐atom transfer (HAT) process has emerged as a promising method for accessing functionally diverse enantioenriched ...products, while asymmetric C(sp3)−H bond amination remains a formidable challenge. To address this problem, described herein is a dual CuI/chiral phosphoric acid (CPA) catalytic system for radical‐involved enantioselective intramolecular C(sp3)−H amination of not only allylic positions but also benzylic positions with broad substrate scope. The use of 4‐methoxy‐NHPI (NHPI=N‐hydroxyphthalimide) as a stable and chemoselective HAT mediator precursor is crucial for the fulfillment of this transformation. Preliminary mechanistic studies indicate that a crucial allylic or benzylic radical intermediate resulting from a HAT process is involved.
Radical control: The first radical‐involved intramolecular enantioselective oxidative C−H amination of not only allylic substrates, but also benzylic substrates, by a hydrogen atom transfer process with a CuI/chiral phosphoric acid catalytic system is reported. Critical to the success is the use of 4‐methoxy‐PINO as a stable and chemoselective hydrogen or.
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