LAD-Net: A Novel Light Weight Model for Early Apple Leaf Pests and Diseases Classification.

Aphids, brown spots, mosaics, rusts, powdery mildew and Alternaria blotches are common types of early apple leaf pests and diseases that severely affect the yield and quality of apples. Recently, deep learning has been regarded as the best classification model for apple leaf pests and diseases. However, these models with large parameters have difficulty providing an accurate and fast diagnosis of apple leaf pests and diseases on mobile terminals. This paper proposes a novel and real-time early apple leaf disease recognition model. AD Convolution is firstly utilized to replace standard convolution to make smaller number of parameters and calculations. Meanwhile, a LAD-Inception is built to enhance the ability of extracting multiscale features of different sizes of disease spots. Finally, the LAD-Net model is built by the LR-CBAM and the LAD-Inception modules, replacing a full connection with global average pooling to further reduce parameters. The results show that the LAD-Net, with a size of only 1.25MB, can achieve a recognition performance of 98.58%. Additionally, it is only delayed by 15.2ms on HUAWEI P40 and by 100.1ms on Jetson Nano, illustrating that the LAD-Net can accurately recognize early apple leaf pests and diseases on mobile devices in real-time, providing portable technical support.

Engineering Single-Atom Iron Nanozymes with Radiation-Enhanced Self-Cascade Catalysis and Self-Supplied H2O2 for Radio-enzymatic Therapy.

Single-atom nanozymes (SAzymes), with individually isolated metal atom as active sites, have shown tremendous potential as enzyme-based drugs for enzymatic therapy. However, using SAzymes in tumor theranostics remains challenging because of deficient enzymatic activity and insufficient endogenous H2O2. We develop an external-field-enhanced catalysis by an atom-level engineered FeN4-centered nanozyme (FeN4-SAzyme) for radio-enzymatic therapy. This FeN4-SAzyme exhibits peroxidase-like activity capable of catalyzing H2O2 into hydroxyl radicals and converting single-site FeII species to FeIII for subsequent glutathione oxidase-like activity. Density functional theory calculations are used to rationalize the origin of the single-site self-cascade enzymatic activity. Importantly, using X-rays can improve the overall single-site cascade enzymatic reaction process via promoting the conversion frequency of FeII/FeIII. As a H2O2 producer, natural glucose oxidase is further decorated onto the surface of FeN4-SAzyme to yield the final construct GOD@FeN4-SAzyme. The resulting GOD@FeN4-SAzyme not only supplies in situ H2O2 to continuously produce highly toxic hydroxyl radicals but also induces the localized deposition of radiation dose, subsequently inducing intensive apoptosis and ferroptosis in vitro. Such a synergistic effect of radiotherapy and self-cascade enzymatic therapy allows for improved tumor growth inhibition with minimal side effects in vivo. Collectively, this work demonstrates the introduction of external fields to enhance enzyme-like performance of nanozymes without changing their properties and highlights a robust therapeutic capable of self-supplying H2O2 and amplifying self-cascade reactions to address the limitations of enzymatic treatment.

Multi-biofunctional graphene oxide-enhanced poly-L-lactic acid composite nanofiber scaffolds for ovarian function recovery of transplanted-tissue.

In this study, we successfully constructed the new graphene oxide/poly-L-lactic acid (GO/PLLA) nanofiber scaffolds with a hydrophilic surface and porous network structure that were highly favorable for cell infiltration. When employed these new nanofiber scaffolds for a wide range of tissue engineering applications, it was expected to promote graft tissue survival and angiogenesis. The new GO/PLLA nanofiber scaffold with an appropriate concentration of 1.0 wt% was applied for the restoration of ovarian function and reserve in mice with primary ovarian insufficiency (POI). After co-transplanting the normal ovarian cortex loaded on these new nanomaterials into the in situ ovarian tissue of POI mice, the fusion of transplanted ovarian cortex with damaged ovarian tissue was improved, as well as the ovarian function and the follicle numbers. Moreover, angiogenesis was observed clearly and proved to exist in the transplanted tissue and nanomaterials, with the most conspicuous effect after co-transplantation with 1.0 wt% GO/PLLA nanofiber scaffold. In addition, nitric oxide (NO) production by phosphorylated endothelial nitric oxide synthase (p-eNOS) in vivo was proven to be involved in the effect of GO and PLLA on the improved survival rate of the transplanted ovarian cortex. This study provides a new method for the fertility preservation of ovarian tissue cryopreservation and transplantation, as well as a new strategy for the transplantation of other organs.

Effects of Titanium Dioxide Nanoparticles on Cell Growth and Migration of A549 Cells under Simulated Microgravity.

With the increasing application of nanomaterials in aerospace technology, the long-term space exposure to nanomaterials especially in the space full of radiation coupled with microgravity condition has aroused great health concerns of the astronauts. However, few studies have been conducted to assess these effects, which are crucial for seeking the possible intervention strategy. Herein, using a random positioning machine (RPM) to simulate microgravity, we investigated the behaviors of cells under simulated microgravity and also evaluated the possible toxicity of titanium dioxide nanoparticles (TiO2 NPs), a multifunctional nanomaterial with potential application in aerospace. Pulmonary epithelial cells A549 were exposed to normal gravity (1 g) and simulated gravity (~10-3 g), respectively. The results showed that simulated microgravity had no significant effect on the viability of A549 cells as compared with normal gravity within 48 h. The effects of TiO2 NPs exposure on cell viability and apoptosis were marginal with only a slightly decrease in cell viability and a subtle increase in apoptosis rate observed at a high concentration of TiO2 NPs (100 µg/mL). However, it was observed that the exposure to simulated microgravity could obviously reduce A549 cell migration compared with normal gravity. The disruption of F-actin network and the deactivation of FAK (Tyr397) might be responsible for the impaired mobility of simulated microgravity-exposed A549 cells. TiO2 NPs exposure inhibited cell migration under two different gravity conditions, but to different degrees, with a milder inhibition under simulated microgravity. Meanwhile, it was found that A549 cells internalized more TiO2 NPs under normal gravity than simulated microgravity, which may account for the lower cytotoxicity and the lighter inhibition of cell migration induced by the same exposure concentration of TiO2 NPs under simulated microgravity at least partially. Our study has provided some tentative information on the effects of TiO2 NPs exposure on cell behaviors under simulated microgravity.

Transformable Gallium-Based Liquid Metal Nanoparticles for Tumor Radiotherapy Sensitization.

The past decades have witnessed an increasing interest in the exploration of room temperature gallium-based liquid metal (LM) in the field of microfluidics, soft robotics, electrobiology, and biomedicine. Herein, this study for the first time reports the utilization of nanosized gallium-indium eutectic alloys (EGaIn) as a radiosensitizer for enhancing tumor radiotherapy. The sodium alginate (Alg) functionalized EGaIn nanoparticles (denoted as EGaIn@Alg NPs) are prepared via a simple one-step synthesis method. The coating of Alg not only prevents the aggregation and oxidation of EGaIn NPs in an aqueous solution but also enables them low cytotoxicity, good biocompatibility, and in-situ formation of gels in the Ca2+ enriched tumor physiological microenvironment. Due to the metallic nature and high density, EGaIn can increase the generation of reactive oxygen species under the irradiation of X-ray, which can not only directly promote DNA damage and cell apoptosis, but also show an efficient tumor inhibition rate in vivo. Moreover, EGaIn@Alg NPs hold good performance as computed tomography (CT) and photoacoustic tomography (PAT) imaging contrast agents. This work provides an alternative nanotechnology strategy for tumor radiosensitization and also enlarges the biomedical application of gallium-based LM.

WR-GLP2, a glucagon-like peptide 2 from hybrid crucian carp that protects intestinal mucosal barrier and inhibits bacterial infection.

Glucagon-like peptide 2 (GLP2) is a proglucagon-derived peptide produced by intestinal enteroendocrine L-cells. The main biological actions of GLP2 in mammals are related to regulating energy absorption and maintaining the morphology, integrity of intestinal mucosa. However, the in vivo function of fish GLP2 in intestinal barrier and immune defense is essentially unknown. With an aim to elucidate the antimicrobial mechanism of GLP2 in fish, we in this study examined the function of GLP2 from hybrid crucian carp. Hybrid crucian carp GLP2 (WR-GLP2) possesses the conserved glucagon like hormones 2 domain. WR-GLP2 is mainly expressed in the intestine and is significantly upregulated after Aeromonas hydrophila infection. AB-PAS staining analysis showed WR-GLP2 significantly increased the number of goblet cells in intestine. WR-GLP2 induced significant inductions in the expression of the antimicrobial molecules (MUC2, Lyzl-1, Hepcidin-1 and LEAP-2) and tight junctions (ZO-1, Occludin and Claudin-4). In addition, WR-GLP2 significantly alleviated the intestinal apoptosis, thereby enhancing host's resistance against Aeromonas hydrophila infection. Together these results indicate that WR-GLP2 is involved in intestinal mucosal barrier and immune defense against pathogen infection.

Highly Stable Silica-Coated Bismuth Nanoparticles Deliver Tumor Microenvironment-Responsive Prodrugs to Enhance Tumor-Specific Photoradiotherapy.

Radiosensitizers are agents capable of amplifying injury to tumor tissues by enhancing DNA damage and fortifying production of radical oxygen species (ROS). The use of such radiosensitizers in the clinic, however, remains limited by an insufficient ability to differentiate between cancer and normal cells and by the presence of a reversible glutathione system that can diminish the amount of ROS generated. Here, to address these limitations, we design an H2O2-responsive prodrug which can be premixed with lauric acid (melting point ∼43 °C) and loaded around the surface of silica-coated bismuth nanoparticles (BSNPs) for cancer-specific photoradiotherapy. Particularly, silica coating confers BSNPs with improved chemical stability against both near-infrared light and X-rays. Upon photothermal heating, lauric acid is melted to trigger prodrug release, followed by its transformation into p-quinone methide via H2O2 stimulation to irreversibly alkylate glutathione. Concurrently, this heat boosts tumor oxygenation and helps relieve the hypoxic microenvironment. Following sequential irradiation by X-rays, BSNPs generate plentiful ROS, which act in combination with these events to synergistically induce cell death via DNA breakage and mitochondria-mediated apoptosis pathways, ultimately enabling effective inhibition of tumor growth in vivo with high tumor specificity and reduced side effects. Collectively, this work presents a promising approach for the improvement of other ROS-responsive proalkylating agents, while simultaneously highlighting a robust nanosystem for combining these prodrugs with photoradiosensitizers to realize precision photoradiotherapy.

Characterization of the Specific Mode of Action of a Chitin Deacetylase and Separation of the Partially Acetylated Chitosan Oligosaccharides.

Partially acetylated chitosan oligosaccharides (COS), which consists of N-acetylglucosamine (GlcNAc) and glucosamine (GlcN) residues, is a structurally complex biopolymer with a variety of biological activities. Therefore, it is challenging to elucidate acetylation patterns and the molecular structure-function relationship of COS. Herein, the detailed deacetylation pattern of chitin deacetylase from Saccharomyces cerevisiae, ScCDA2, was studied. Which solves the randomization of acetylation patterns during COS produced by chemical. ScCDA2 also exhibits about 8% and 20% deacetylation activity on crystalline chitin and colloid chitin, respectively. Besides, a method for separating and detecting partially acetylated chitosan oligosaccharides by high performance liquid chromatography and electrospray ionization mass spectrometry (HPLC-ESI-MS) system has been developed, which is fast and convenient, and can be monitored online. Mass spectrometry sequencing revealed that ScCDA2 produced COS with specific acetylation patterns of DAAA, ADAA, AADA, DDAA, DADA, ADDA and DDDA, respectively. ScCDA2 does not deacetylate the GlcNAc unit that is closest to the reducing end of the oligomer furthermore ScCDA2 has a multiple-attack deacetylation mechanism on chitin oligosaccharides. This specific mode of action significantly enriches the existing limited library of chitin deacetylase deacetylation patterns. This fully defined COS may be used in the study of COS structure and function.

Insight into carrageenases: major review of sources, category, property, purification method, structure, and applications.

Carrageenan, a kind of linear sulfated polysaccharides consisting of D-galactose with alternating α-1,3 and ß-1,4 linkages, has been widely applied in the food and cosmetic industries as thickening and gelling agents due to excellent properties, such as gel-forming ability and chemical stability. It can be degraded by carrageenases to produce a series of even-numbered carrageenan oligosaccharides, which exhibit various fascinating functions, such as anti-inflammation, anti-coagulation, anti-tumor, and anti-thrombosis effects. Numerous carrageenases have been isolated and identified from various sources. The enzymes are grouped into three categories, namely κ-carrageenase, ι-carrageenase, and λ-carrageenase based on their substrate specificities and primary sequences, respectively. Elucidating the paradigm of the enzyme at every aspect would definitely enhance our understanding of the marine carbon cycling and natural evolution of glycoside hydrolases (GHs). The structural features of these enzymes have been fully illustrated, which will improve our knowledge of its catalytic mechanisms. In this review, we have summarized the recent progresses of major sources, category, and the enzyme's biochemical characteristics. Additionally, structural characteristics and catalytic mechanisms have been introduced in detail. We conclude with a brief discussion of the potential of the carrageenases in possible future applications in preparing functional oligosaccharides with versatile activities. This comprehensive information should be helpful regarding the application of carrageenases.

A new approach to improve the electrochemical performance of ZnMn2O4 through a charge compensation mechanism using the substitution of Al3+ for Zn2.

ZnMn2O4 and Zn1-x Al x Mn2O4 were synthesized by a spray drying process followed by an annealing treatment. Their structural and electrochemical characteristics were investigated by SEM, XRD, XPS, charge-discharge tests and EIS. XPS data indicate that the substitution of Al3+ for Zn2+ causes manganese to be in a mixed valence state by a charge compensation mechanism. Moreover, the presence of this charge compensation significantly improves the electrochemical performance of Zn1-x Al x Mn2O4, such as increasing the initial coulombic efficiency, stabilizing the cycleability as well as improving the rate capability. The sample with 2% Al doping shows the best performance, with a first cycle coulombic efficiency of 69.6% and a reversible capacity of 597.7 mA h g-1 after 100 cycles. Even at the high current density of 1600 mA g-1, it still retained a capacity of 558 mA h g-1.