Differential gene expression analysis of spatial transcriptomic experiments using spatial mixed models.

Spatial transcriptomics (ST) assays represent a revolution in how the architecture of tissues is studied by allowing for the exploration of cells in their spatial context. A common element in the analysis is delineating tissue domains or "niches" followed by detecting differentially expressed genes to infer the biological identity of the tissue domains or cell types. However, many studies approach differential expression analysis by using statistical approaches often applied in the analysis of non-spatial scRNA data (e.g., two-sample t-tests, Wilcoxon's rank sum test), hence neglecting the spatial dependency observed in ST data. In this study, we show that applying linear mixed models with spatial correlation structures using spatial random effects effectively accounts for the spatial autocorrelation and reduces inflation of type-I error rate observed in non-spatial based differential expression testing. We also show that spatial linear models with an exponential correlation structure provide a better fit to the ST data as compared to non-spatial models, particularly for spatially resolved technologies that quantify expression at finer scales (i.e., single-cell resolution).

Trisomy 8 Defines a Distinct Subtype of Myeloproliferative Neoplasms Driven by the MYC-Alarmin Axis.

Despite advances in understanding the genetic abnormalities in myeloproliferative neoplasms (MPNs) and the development of JAK2 inhibitors, there is an urgent need to devise new treatment strategies, particularly for triple negative myelofibrosis (MF) patients who lack mutations in the JAK2 kinase pathway and have very poor clinical outcomes. Here we report that MYC copy number gain and increased MYC expression frequently occur in triple negative MF, and that MYC-directed activation of S100A9, an alarmin protein that plays pivotal roles in inflammation and innate immunity, is necessary and sufficient to drive development and progression of MF. Notably, the MYC-S100A9 circuit provokes a complex network of inflammatory signaling that involves numerous hematopoietic cell types in the bone marrow microenvironment. Accordingly, genetic ablation of S100A9 or treatment with small molecules targeting the MYC-S100A9 pathway effectively ameliorates MF phenotypes, highlighting the MYC-alarmin axis as a novel therapeutic vulnerability for this subgroup of MPNs.

Glucose-driven histone lactylation promotes the immunosuppressive activity of monocyte-derived macrophages in glioblastoma.

Immunosuppressive macrophages restrict anti-cancer immunity in glioblastoma (GBM). Here, we studied the contribution of microglia (MGs) and monocyte-derived macrophages (MDMs) to immunosuppression and mechanisms underlying their regulatory function. MDMs outnumbered MGs at late tumor stages and suppressed T cell activity. Molecular and functional analysis identified a population of glycolytic MDM expressing GLUT1 with potent immunosuppressive activity. GBM-derived factors promoted high glycolysis, lactate, and interleukin-10 (IL-10) production in MDMs. Inhibition of glycolysis or lactate production in MDMs impaired IL-10 expression and T cell suppression. Mechanistically, intracellular lactate-driven histone lactylation promoted IL-10 expression, which was required to suppress T cell activity. GLUT1 expression on MDMs was induced downstream of tumor-derived factors that activated the PERK-ATF4 axis. PERK deletion in MDM abrogated histone lactylation, led to the accumulation of intratumoral T cells and tumor growth delay, and, in combination with immunotherapy, blocked GBM progression. Thus, PERK-driven glucose metabolism promotes MDM immunosuppressive activity via histone lactylation.

Clonal expansion of shared T cell receptors reveals the existence of immune commonality among different lesions of synchronous multiple primary lung cancer.

The increase in the detection rate of synchronous multiple primary lung cancer (MPLC) has posed remarkable clinical challenges due to the limited understanding of its pathogenesis and molecular features. Here, comprehensive comparisons of genomic and immunologic features between MPLC and solitary lung cancer nodule (SN), as well as different lesions of the same patient, were performed. Compared with SN, MPLC displayed a lower rate of EGFR mutation but higher rates of BRAF, MAP2K1, and MTOR mutation, which function exactly in the upstream and downstream of the same signaling pathway. Considerable heterogeneity in T cell receptor (TCR) repertoire exists among not only different patients but also among different lesions of the same patient. Invasive lesions of MPLC exhibited significantly higher TCR diversity and lower TCR expansion than those of SN. Intriguingly, different lesions of the same patient always shared a certain proportion of TCR clonotypes. Significant clonal expansion could be observed in shared TCR clonotypes, particularly in those existing in all lesions of the same patient. In conclusion, this study provided evidences of the distinctive mutational landscape, activation of oncogenic signaling pathways, and TCR repertoire in MPLC as compared with SN. The significant clonal expansion of shared TCR clonotypes demonstrated the existence of immune commonality among different lesions of the same patient and shed new light on the individually tailored precision therapy for MPLC.

The functional role of L-fucose on dendritic cell function and polarization.

Despite significant advances in the development and refinement of immunotherapies administered to combat cancer over the past decades, a number of barriers continue to limit their efficacy. One significant clinical barrier is the inability to mount initial immune responses towards the tumor. As dendritic cells are central initiators of immune responses in the body, the elucidation of mechanisms that can be therapeutically leveraged to enhance their functions to drive anti-tumor immune responses is urgently needed. Here, we report that the dietary sugar L-fucose can be used to enhance the immunostimulatory activity of dendritic cells (DCs). L-fucose polarizes immature myeloid cells towards specific DC subsets, specifically cDC1 and moDC subsets. In vitro, L-fucose treatment enhances antigen uptake and processing of DCs. Furthermore, our data suggests that L-fucose-treated DCs increase stimulation of T cell populations. Consistent with our functional assays, single-cell RNA sequencing of intratumoral DCs from melanoma- and breast tumor-bearing mice confirmed transcriptional regulation and antigen processing as pathways that are significantly altered by dietary L-fucose. Together, this study provides the first evidence of the ability of L-fucose to bolster DC functionality and provides rational to further investigate how L-fucose can be used to leverage DC function in order to enhance current immunotherapy.

A pyroptosis-related lncRNA-based prognostic index for hepatocellular carcinoma by relative expression orderings.

Background: Hepatocellular carcinoma (HCC) is an invasive malignant tumor, and pyroptosis makes an important contribution to the pathology and progression of liver cancer. Many prognostic models have been proposed for HCC based on the quantitative expression level of candidate genes, which are unsuitable for clinical application due to their vulnerability against experimental batch effects. The aim of this study was to develop a novel pyroptosis-related long non-coding RNA (lncRNA)-based prognostic index (PLPI) for HCC based on relative expression orderings (REOs). Methods: Firstly, the pyroptosis-related lncRNAs were identified through the Wilcoxon rank-sum test and gene co-expression analyses. Then, the novel prognostic model PLPI was constructed by pyroptosis-related lncRNA pairs, which were identified by multiple machine learning algorithms. Gene set enrichment, somatic mutation, and drug sensitivity analyses were conducted to measure the differences between high- and low-risk patients. Multiple immune analyses were used to explore the association between PLPI and the immunological microenvironment. Results: In this study, a novel prognostic model PLPI based on 10 pyroptosis-related lncRNA pairs was constructed, which was proven to be an independent prognostic risk factor. The receiver operating characteristic (ROC) curves showed that the model had a good prognostic ability in the training, testing, and external set, respectively [5-year area under the curve (AUC) =0.73, 5-year AUC =0.81, 4-year AUC =0.79]. The results of survival, somatic mutation, and immune analyses showed that the patients in the low-risk group had a better prognosis, lower rates of somatic mutation, and better immune cell infiltration. Personalized chemotherapeutic drugs were also identified for the patients with HCC. Conclusions: The novel PLPI not only greatly predicted the prognosis of patients with HCC but could also offer novel ideas and approaches for the therapeutic management of HCC.

Study on immune persistence of the CTN-1V strain rabies vaccine in humans.

This study is a single-arm, single-center phase IV clinical trial on a rabies vaccine that has been marketed in China. The Vero cells and CTN-1V strain are used in the rabies vaccine product. The purpose of this study was to investigate the safety, immunogenicity and immune persistence of this product. One hundred and forty-nine participants were enrolled to the study, all of whom were included in the safety analysis set (SS), among which 116 participants were included in the protocol analysis set (PPS), One hundred and fifteen participants were included in the 6-month immune persistence analysis set (IPS6) and 111 in the 12-month immune persistence analysis set IPS12. Results showed that: 1) In the SS analysis set, adverse reactions were mainly pyrexia and pain at the vaccination site, the severity of which were mostly grade 1, and concentrated in 0-3 days after vaccination. No grade 3 or above adverse events and serious adverse events (SAE) related to the experimental vaccine were observed. 2) In the PPS analysis set, the antibody positive conversion rate reached 100% at 14 days after full immunization of the pre-immunized negative population; The antibody geometric mean titer (GMT) (95% CI) was 14.82 (13.00, 16.90). 3) The positive rate of serum neutralizing antibody was 93.91 % and the GMT at 1.58 IU/ml at 6 months after full immunization. The positive rate of neutralizing antibody was 85.59 % and GMT at 1.30 IU/ml at 12 months after immunization. Our results show that the human rabies vaccine with the CTN-1V strain and Vero cells as matrix had good safety, immunogenicity and immune persistence in our study.

High-quality acrylic fibers from waste textiles.

The objective of this work is to develop a closed-loop recycling method specifically tailored for acrylic fibers. Recycling waste acrylic is essential, given the vast volumes of acrylic-containing textiles produced yearly and the strong capability of acrylics to generate toxic microplastics. However, none of the available closed-loop recycling, mechanical recycling, chemical recycling, and direct extrusion technologies work for acrylics. Acrylic fibers are always blended with other textile fibers, making fiber separation via mechanical recycling almost impossible. Polyacrylonitrile, an addition-polymerized thermoplastic material, cannot be depolymerized into its original monomer. Direct extrusion of waste acrylics faces issues of uncontrollable colors on fibers and pollution of spinning lines due to the influence of existing colorants. In our method, acrylic fibers were extracted from waste textiles using a novel approach involving maximized acrylic swelling and dissolution with dimethyl sulfoxide and butanediol. Cationic dyes were effectively removed through cost-effective recycling technology. This work demonstrates that cationic dyes seriously affect the acrylic dissolution, color consistency, and dyeability of regenerated fibers via direct wet extrusion. Such negative impacts of dyes have been eliminated by our cost-effective and closed-loop acrylic recycling technology, which enables the efficient separation of non-acrylic fibers and dyes from acrylic fibers. Our recycling system achieved zero discharges through recycling solvents, dyes, and acrylics. The regenerated acrylic fibers exhibited mechanical properties and dyeability comparable to virgin acrylic fibers. The material and energy costs to produce pure acrylic from waste textiles were only 40 % of those from fossils. This study successfully introduces a closed-loop recycling method for acrylic fibers from waste textiles, addressing key challenges in acrylic fiber recycling. Further research and implementation of this technology are recommended to advance its commercial viability and widespread adoption.

Jagged2 targeting in lung cancer activates anti-tumor immunity via Notch-induced functional reprogramming of tumor-associated macrophages.

Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in non-small cell lung cancer (NSCLC). Higher expression of JAG2 in NSCLC negatively correlated with survival. In NSCLC pre-clinical models, deletion of Jag2, but not Jag1, in cancer cells attenuated tumor growth and activated protective anti-tumor T cell responses. Jag2-/- lung tumors exhibited higher frequencies of macrophages that expressed immunostimulatory mediators and triggered T cell-dependent anti-tumor immunity. Mechanistically, Jag2 ablation promoted Nr4a-mediated induction of Notch ligands DLL1/4 on cancer cells. DLL1/4-initiated Notch1/2 signaling in macrophages induced the expression of transcription factor IRF4 and macrophage immunostimulatory functionality. IRF4 expression was required for the anti-tumor effects of Jag2 deletion in lung tumors. Antibody targeting of Jagged2 inhibited tumor growth and activated IRF4-driven macrophage-mediated anti-tumor immunity. Thus, Jagged2 orchestrates immunosuppressive systems in NSCLC that can be overcome to incite macrophage-mediated anti-tumor immunity.

Nitric oxide nano-reactor DNMF/PLGA enables tumor vascular microenvironment and chemo-hyperthermia synergetic therapy.

BACKGROUND: Breast cancer ranks first among malignant tumors, of which triple-negative breast cancer (TNBC) is characterized by its highly invasive behavior and the worst prognosis. Timely diagnosis and precise treatment of TNBC are substantially challenging. Abnormal tumor vessels play a crucial role in TNBC progression and treatment. Nitric oxide (NO) regulates angiogenesis and maintains vascular homeostasis, while effective NO delivery can normalize the tumor vasculature. Accordingly, we have proposed here a tumor vascular microenvironment remodeling strategy based on NO-induced vessel normalization and extracellular matrix collagen degradation with multimodality imaging-guided nanoparticles against TNBC called DNMF/PLGA. RESULTS: Nanoparticles were synthesized using a chemotherapeutic agent doxorubicin (DOX), a NO donor L-arginine (L-Arg), ultrasmall spinel ferrites (MnFe2O4), and a poly (lactic-co-glycolic acid) (PLGA) shell. Nanoparticle distribution in the tumor was accurately monitored in real-time through highly enhanced magnetic resonance imaging and photoacoustic imaging. Near-infrared irradiation of tumor cells revealed that MnFe2O4 catalyzes the production of a large amount of reactive oxygen species (ROS) from H2O2, resulting in a cascade catalysis of L-Arg to trigger NO production in the presence of ROS. In addition, DOX activates niacinamide adenine dinucleotide phosphate oxidase to generate and supply H2O2. The generated NO improves the vascular endothelial cell integrity and pericellular contractility to promote vessel normalization and induces the activation of endogenous matrix metalloproteinases (mainly MMP-1 and MMP-2) so as to promote extravascular collagen degradation, thereby providing an auxiliary mechanism for efficient nanoparticle delivery and DOX penetration. Moreover, the chemotherapeutic effect of DOX and the photothermal effect of MnFe2O4 served as a chemo-hyperthermia synergistic therapy against TNBC. CONCLUSION: The two therapeutic mechanisms, along with an auxiliary mechanism, were perfectly combined to enhance the therapeutic effects. Briefly, multimodality image-guided nanoparticles provide a reliable strategy for the potential application in the fight against TNBC.

UPLC-Q-TOF/MS analysis of chemical components of single decoction and combined decoction of Qige decoction reveals the differences between various preparation processes.

The aim of this work was to explore the differences between various pharmaceutical processes in combined solutions of a single decoction (QGHBY) and a combined decoction (QGHJY) of Qi-Ge decoction from the perspective of chemical composition changes, so as to further guide the clinical application of drugs. A combined solution of a single decoction and a combined decoction of Astragali Radix, Puerariae Lobatae Radix and Citri Reticulatae Chachiensis Pericarpium was prepared with the same technological parameters. The chemical components of the two were detected and identified based on UPLC-Q-TOF/MS, and the different components were determined by principal component analysis. Eighty-eight compounds were identified in the pharmaceutical solution of Qi-Ge decoction. Principal component analysis revealed 11 different components of QGHBY and QGHJY with the conditions of Variable Importance in Projection (VIP) ≥ 1, fold change ≥ 2 and p < 0.05, among which hesperidin, hesperitin, isosinensetin, sinensetin and 5-demethylnobiletin were the components of Citri Reticulatae Chachiensis Pericarpium. The levels of these 11 different components in QGHJY were higher than those of QGHBY. The combined decoction is beneficial for the dissolution of flavonoids and other chemical components, and there is a significant difference in the content of chemical components between modern herbal concentrate granules and traditional decoctions.

Facile Access to High Solid Content Monodispersed Microspheres via Dual-Component Surfactants Regulation toward High-Performance Colloidal Photonic Crystals.

Monodispersed microspheres play a major role in optical science and engineering, providing ideal building blocks for structural color materials. However, the method toward high solid content (HSC) monodispersed microspheres has remained a key hurdle. Herein, a facile access to harvest monodispersed microspheres based on the emulsion polymerization mechanism is demonstrated, where anionic and nonionic surfactants are employed to achieve the electrostatic and steric dual-stabilization balance in a synergistic manner. Monodispersed poly(styrene-butyl acrylate-methacrylic acid) colloidal latex with 55 wt% HSC is achieved, which shows an enhanced self-assembly efficiency of 280% compared with the low solid content (10 wt%) latex. In addition, Ag-coated colloidal photonic crystal (Ag@CPC) coating with near-zero refractive index is achieved, presenting the characteristics of metamaterials. And an 11-fold photoluminescence emission enhancement of CdSe@ZnS quantum dots is realized by the Ag@CPC metamaterial coating. Taking advantage of high assembly efficiency, easily large-scale film-forming of the 55 wt% HSC microspheres latex, robust Ag@CPC metamaterial coatings could be easily produced for passive cooling. The coating demonstrates excellent thermal insulation performance with theoretical cooling power of 30.4 W m-2, providing practical significance for scalable CPC architecture coatings in passive cooling.

Heterodyne-Detected Sum-Frequency Generation Vibrational Spectroscopy Reveals Aqueous Molecular Structure at the Suspended Graphene/Water Interface.

Graphene, a transparent two-dimensional conductive material, has brought extensive new perspectives and prospects to various aqueous technological systems, such as desalination membranes, chemical sensors, energy storage, and energy conversion devices. Yet, the molecular-level details of graphene in contact with aqueous electrolytes, such as water orientation and hydrogen bond structure, remain elusive or controversial. Here, we employ surface-specific heterodyne-detected sum-frequency generation (HD-SFG) vibrational spectroscopy to re-examine the water molecular structure at a freely suspended graphene/water interface. We compare the response from the air/graphene/water system to that from the air/water interface. Our results indicate that the χ y y z 2 ${{\chi }_{yyz}^{\left(2\right)}}$ spectrum recorded from the air/graphene/water system arises from the topmost 1-2 water layers in contact with the graphene, with the graphene itself not generating a significant SFG response. Compared to the air/water interface response, the presence of monolayer graphene weakly affects the interfacial water. Graphene weakly affects the dangling O-H group, lowering its frequency through its interaction with the graphene sheet, and has a very small effect on the hydrogen-bonded O-H group. Molecular dynamics simulations confirm our experimental observation. Our work provides molecular insight into the interfacial structure at a suspended graphene/water interface, relevant to various technological applications of graphene.

Severe cough and hemoptysis induced reopening of patent foramen ovale leading to significant decrease in pulmonary artery pressure in a patient with idiopathic pulmonary arterial hypertension： A case report.

Pulmonary arterial hypertension (PAH) is a perilous disease that precipitates right ventricular hypertrophy, induces right heart failure, and exerts deleterious ramifications on prognostic outcomes. The establishment of atrial communication can create a right-to-left shunt, thereby ameliorating hemodynamic parameters. Previous reports suggested that opening of a patent foramen ovale (PFO) was common in patients with severe PAH, but exhibited no discernible impact on long-term survival. We reported the case of a 39-year-old man with severe idiopathic PAH, who underwent reopening of the PFO due to severe cough and hemoptysis, followed by a marked amelioration in symptoms and a substantial decrease in pulmonary arterial pressure. The patient has survived for more than 12 years, persisting in World Health Organization functional class Ⅱ with mild PAH.

Scaled Production of Functionally Gradient Thin Films Using Slot Die Coating on a Roll-to-Roll System.

Polymer thin films with a cross-web gradient structure is a burgeoning area of research, having received more attention in the last two decades, for improvements in the performance and material properties. Such patterned films have been fabricated using several techniques, but in practice these techniques are non-scalable, material-dependent, wasteful, and not highly efficient. Slot die coating, a well-known scalable manufacturing process, is used to fabricate gradient polymer thin films which will be investigated herein. By incorporating slot die with the custom roll-to-roll imaging system, gradient thin films are successfully fabricated by forcing two fluidic materials into the slot die simultaneously and by manipulating the viscous, diffusive, and inertial forces. The materials will be allowed to intermix, with the aim of having approximately a 50% mix along the centerline of any two contiguous stripes. Moreover, several characterizations such as FTIR, UV-vis spectroscopy, and SEM are performed to assess the quality of the gradient polymer thin films. The gradient structure fabricated using functional and nonfunctional materials has successfully improved the functional properties compared to fully blended two materials. This work will provide an understanding of the mechanisms to obtain gradient polymer thin-film structures that exhibit the desired geometric structure and performance.

Sodium Butyrate Alleviates Free Fatty Acid-Induced Steatosis in Primary Chicken Hepatocytes via Regulating the ROS/GPX4/Ferroptosis Pathway.

Fatty liver hemorrhagic syndrome (FLHS) in laying hens is a nutritional metabolic disease commonly observed in high-yielding laying hens. Sodium butyrate (NaB) and ferroptosis were reported to contribute to the pathogenesis of fatty liver-related diseases. However, the underlying mechanism of NaB in FLHS and whether it mediates ferroptosis remains unclear. A chicken primary hepatocyte induced by free fatty acids (FFAs, keeping the ratio of sodium oleate and sodium palmitate concentrations at 2:1) was established, which received treatments with NaB, the ferroptosis inducer RAS-selective lethal 3 (RSL3), and the inhibitor ferrostatin-1 (Fer-1). As a result, NaB increased biochemical and lipid metabolism indices, and the antioxidant level, while inhibiting intracellular ROS accumulation and the activation of the ferroptosis signaling pathway, as evidenced by a reduction in intracellular iron concentration, upregulated GPX4 and xCT expression, and inhibited NCOA4 and ACSL4 expression. Furthermore, treatment with Fer-1 reinforced the protective effects of NaB, while RSL3 reversed it by blocking the ROS/GPX4/ferroptosis pathway, leading to the accumulation of lipid droplets and oxidative stress. Collectively, our findings demonstrated that NaB protects hepatocytes by regulating the ROS/GPX4-mediated ferroptosis pathway, providing a new strategy and target for the treatment of FLHS.

Spontaneous Appearance of Triiodide Covering the Topmost Layer of the Iodide Solution Interface Without Photo-Oxidation.

Ions containing iodine atoms at the vapor-aqueous solution interfaces critically affect aerosol growth and atmospheric chemistry due to their complex chemical nature and multivalency. While the surface propensity of iodide ions has been intensely discussed in the context of the Hofmeister series, the stability of various ions containing iodine atoms at the vapor-water interface has been debated. Here, we combine surface-specific sum-frequency generation (SFG) vibrational spectroscopy with ab initio molecular dynamics simulations to examine the extent to which iodide ions cover the aqueous surface. The SFG probe of the free O-D stretch mode of heavy water indicates that the free O-D group density decreases drastically at the interface when the bulk NaI concentration exceeds ∼2 M. The decrease in the free O-D group density is attributed to the spontaneous appearance of triiodide that covers the topmost interface rather than to the surface adsorption of iodide. This finding demonstrates that iodide is not surface-active, yet the highly surface-active triiodide is generated spontaneously at the water-air interface, even under dark and oxygen-free conditions. Our study provides an important first step toward clarifying iodine chemistry and pathways for aerosol formation.

Histone Deacetylase Inhibitors Directly Modulate T Cell Gene Expression and Signaling and Promote Development of Effector-Exhausted T Cells in Murine Tumors.

Epigenetic regulation plays a crucial role in the development and progression of cancer, including the regulation of antitumor immunity. The reversible nature of epigenetic modifications offers potential therapeutic avenues for cancer treatment. In particular, histone deacetylase (HDAC) inhibitors (HDACis) have been shown to promote antitumor T cell immunity by regulating myeloid cell types, enhancing tumor Ag presentation, and increasing expression of chemokines. HDACis are currently being evaluated to determine whether they can increase the response rate of immune checkpoint inhibitors in cancer patients. Although the potential direct effect of HDACis on T cells likely impacts antitumor immunity, little is known about how HDAC inhibition alters the transcriptomic profile of T cells. In this article, we show that two clinical-stage HDACis profoundly impact gene expression and signaling networks in CD8+ and CD4+ T cells. Specifically, HDACis promoted T cell effector function by enhancing expression of TNF-α and IFN-γ and increasing CD8+ T cell cytotoxicity. Consistently, in a murine tumor model, HDACis led to enrichment of CD8+ T cell subsets with high expression of effector molecules (Prf1, Ifng, Gzmk, and Grmb) but also molecules associated with T cell exhaustion (Tox, Pdcd1, Lag3, and Havcr2). HDACis further generated a tumor microenvironment dominated by myeloid cells with immune suppressive signatures. These results indicate that HDACis directly and favorably augment T cell effector function but also increase their exhaustion signal in the tumor microenvironment, which may add a layer of complexity for achieving clinical benefit in combination with immune checkpoint inhibitors.

Interpersonal distance perception during the normalization of an pandemic situation: Effects of mask-wearing and vaccination.

This study aimed to evaluate the effect of anti-pandemic measures, including wearing a face mask and receiving vaccinations, on interpersonal distance (IPD) during the normalization stage of the COVID-19 pandemic. Virtual reality (VR) technology was used to simulate the experimental environment and a confederate in different conditions. Thirty-one participants were asked to approach the virtual confederate, who could exhibit three vaccination states and two mask-wearing conditions, actively and passively in both indoor and outdoor environments. ANOVA results showed that the participants kept a smaller IPD from the confederate wearing a face mask (IPD = 125.6 cm) than from the one without a face mask (IPD = 154.2 cm). The effects of vaccination states were significant, with the largest distance for an unvaccinated confederate (IPD = 182.3 cm) and the smallest distance for the confederate who had received a booster vaccine (IPD = 111.5 cm). Significant effects of environment were also found, with the participants maintaining a larger IPD in an outdoor environment (IPD = 143.4 cm) than in an indoor room (IPD = 136.4 cm). Additionally, the IPD collected when the participants were passively approached (IPD = 149.6 cm) was significantly larger than that obtained when they actively approached the confederate (IPD = 130.3 cm). Moreover, when the participants faced a confederate who had received a booster vaccine and wore a mask, the IPD was not significantly different from that collected before the COVID-19 pandemic in both the active and passive patterns. These findings help us to better understand the nature of IPD and human behaviors during the normalization stage of the pandemic and provide scientific suggestions for policymakers to develop pandemic-prevention measures.

Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones.

Plant protection drone spraying technology is widely used to prevent and control crop diseases and pests due to its advantages of being unaffected by crop growth patterns and terrain restrictions, high operational efficiency, and low labor requirements. The operational parameters of plant protection drones significantly impact the distribution of spray droplets, thereby affecting pesticide utilization. In this study, a field experiment was conducted to determine the working modes of two representative plant protection drones and an electric backpack sprayer as a control to explore the characteristics of droplet deposition with different spray volumes in the citrus canopy. The results showed that the spraying volume significantly affected the number of droplets and the spray coverage. The number of droplets and the spray coverage area on the leaf surface were significantly increased by increasing the spray volume from 60 L/ha to 120 L/ha in plant protection drones. Particularly for the DJI T30, the mid-lower canopy showed a spray coverage increase of 52.5%. The droplet density demonstrated the most significant variations in the lower inner canopy, ranging from 18.7 droplets/cm2 to 41.7 droplets/cm2 by XAG V40. From the deposition distribution on fruit trees, the plant protection drones exhibit good penetration ability, as the droplets can achieve a relatively even distribution in different canopy layers of citrus trees. The droplet distribution uniformity inside the canopy is similar for XAG V40 and DJI T30, with a variation coefficient of approximately 50%-100%. Compared to the plant protection drones, the knapsack electric sprayer is suitable for pest and disease control in the mid-lower canopy, but they face challenges of insufficient deposition capability in the upper canopy and overall poor spray uniformity. The distribution of deposition determined in this study provides data support for the selection of spraying agents for fruit trees by plant protection drones and for the control of different pests and diseases.