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1.
Neurosci Bull ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38592581

RESUMO

Disruption of the blood-spinal cord barrier (BSCB) is a critical event in the secondary injury following spinal cord injury (SCI). Mertk has been reported to play an important role in regulating inflammation and cytoskeletal dynamics. However, the specific involvement of Mertk in BSCB remains elusive. Here, we demonstrated a distinct role of Mertk in the repair of BSCB. Mertk expression is decreased in endothelial cells following SCI. Overexpression of Mertk upregulated tight junction proteins (TJs), reducing BSCB permeability and subsequently inhibiting inflammation and apoptosis. Ultimately, this led to enhanced neural regeneration and functional recovery. Further experiments revealed that the RhoA/Rock1/P-MLC pathway plays a key role in the effects of Mertk. These findings highlight the role of Mertk in promoting SCI recovery through its ability to mitigate BSCB permeability and may provide potential targets for SCI repair.

2.
bioRxiv ; 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38585867

RESUMO

Persistence reinforces continuous action, which benefits animals in many aspects. Diverse information may trigger animals to start a persistent movement. However, it is unclear how the brain decides to persist with current actions by selecting specific information. Using single-unit extracellular recordings and opto-tagging in awake mice, we demonstrated that a group of dorsal mPFC (dmPFC) motor cortex projecting (MP) neurons initiate a persistent movement selectively encoding contextual information rather than natural valence. Inactivation of dmPFC MP neurons impairs the initiation and reduces neuronal activity in the insular and motor cortex. Finally, a computational model suggests that a successive sensory stimulus acts as an input signal for the dmPFC MP neurons to initiate a persistent movement. These results reveal a neural initiation mechanism on the persistent movement.

3.
J Sci Food Agric ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38619112

RESUMO

BACKGROUND: The adhesion of probiotics to the intestine is crucial for their probiotic function. In previous studies, Tremella polysaccharides (TPS) (with sodium casein) have shown the potential to encapsulate probiotics and protect them in a simulated gastrointestinal tract. This study explored the effect of TPS (with sodium casein) on the adhesion of probiotics. RESULTS: Lactobacillus plantarum was coated with TPS and sodium casein in different proportions, and was freeze-dried. The rheological properties of the mixture of probiotics powder and mucin solution were determined by static and dynamic rheological analysis. Aqueous solutions of probiotic powder and mucin mixture exhibited pseudoplastic fluid rheological properties. The higher the proportion of TPS content, the higher the apparent viscosity and yield stress. The mixed bacterial powder and mucin fluid displayed thixotropy and was in accordance with the Herschel-Bulkley model. The TPS increased the bio-adhesive force of the probiotic powder and mucin. When using TPS as the only carbon source, the adhesion of L. plantarum to Caco-2 cells increased by 228% in comparison with glucose in vitro. Twelve adhesive proteins were also detected in the whole-cell proteome of L. plantarum. Among them, ten adhesive proteins occurred abundantly when grown with TPS as a carbon source. CONCLUSION: Tremella polysaccharides therefore possess probiotic properties and can promote the intestinal adhesion of L. plantarum. © 2024 Society of Chemical Industry.

4.
Res Sq ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38585715

RESUMO

Hydrogen Peroxide (H2O2) is a central oxidant in redox biology due to its pleiotropic role in physiology and pathology. However, real-time monitoring of H2O2 in living cells and tissues remains a challenge. We address this gap with the development of an optogenetic hydRogen perOxide Sensor (oROS), leveraging the bacterial peroxide binding domain OxyR. Previously engineered OxyR-based fluorescent peroxide sensors lack the necessary sensitivity and response speed for effective real-time monitoring. By structurally redesigning the fusion of Escherichia coli (E. coli) ecOxyR with a circularly permutated green fluorescent protein (cpGFP), we created a novel, green-fluorescent peroxide sensor oROS-G. oROS-G exhibits high sensitivity and fast on-and-off kinetics, ideal for monitoring intracellular H2O2 dynamics. We successfully tracked real-time transient and steady-state H2O2 levels in diverse biological systems, including human stem cell-derived neurons and cardiomyocytes, primary neurons and astrocytes, and mouse brain ex vivo and in vivo. These applications demonstrate oROS's capabilities to monitor H2O2 as a secondary response to pharmacologically induced oxidative stress and when adapting to varying metabolic stress. We showcased the increased oxidative stress in astrocytes via Aß-putriscine-MAOB axis, highlighting the sensor's relevance in validating neurodegenerative disease models. Lastly, we demonstrated acute opioid-induced generation of H2O2 signal in vivo which highlights redox-based mechanisms of GPCR regulation. oROS is a versatile tool, offering a window into the dynamic landscape of H2O2 signaling. This advancement paves the way for a deeper understanding of redox physiology, with significant implications for understanding diseases associated with oxidative stress, such as cancer, neurodegenerative, and cardiovascular diseases.

5.
Comput Biol Chem ; 110: 108072, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38636391

RESUMO

The methylation and demethylation of lysine and arginine side chains are fundamental processes in gene regulation and disease development. Histone lysine methylation, controlled by histone lysine methyltransferases (KMTs) and histone lysine demethylases (KDMs), plays a vital role in maintaining cellular homeostasis and has been implicated in diseases such as cancer and aging. This study focuses on two members of the lysine demethylase (KDM) family, KDM4E and KDM6B, which are significant in gene regulation and disease pathogenesis. KDM4E demonstrates selectivity for gene regulation, particularly concerning cancer, while KDM6B is implicated in inflammation and cancer. The study utilizes specific inhibitors, DA-24905 and GSK-J1, showcasing their exceptional selectivity for KDM4E and KDM6B, respectively. Employing an array of computational simulations, including sequence alignment, molecular docking, dynamics simulations, and free energy calculations, we conclude that although the binding cavities of KDM4E and KDM6B has high similarity, there are still some different crucial amino acid residues, indicating diverse binding forms between protein and ligands. Various interaction predominates when proteins are bound to different ligands, which also has significant effect on selective inhibition. These findings provide insights into potential therapeutic strategies for diseases by selectively targeting these KDM members.

6.
Heliyon ; 10(8): e29268, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38638976

RESUMO

The establishment of a platelet-apheresis donor database may provide a feasible solution to improve the efficacy of platelet transfusion in patients with immune platelet transfusion refractoriness (PTR). This study aimed to establish HLA genotype database in Suzhou, to provide HLA-I compatible platelets for PTR patients to ensure the safety and effectiveness of platelet transfusions. We used a polymerase chain reaction sequence-based typing (PCR-SBT) method to establish the database by performing high-resolution HLA-A, -B, and -C genotyping on 900 platelet-apheresis donors. HLA-I antibody was detected in patients using a Luminex device, and HLA-I gene matching was performed by an HLA-Matchmaker. We found that the highest frequency of the HLA-A allele was A*11:01 (17.06 %), followed by A*24:02 (14.67 %) and A*02:01 (13.61 %). The highest frequency of the HLA-B allele was B*46:01 (9.78 %), followed by B*40:01 (8.39 %) and B*13:02 (33 %). After the detection of platelet antibodies in 74 patients with immune PTR, we found 30 HLA-A antibodies and 48 HLA-B antibodies, and there were a variety of high frequency antibodies whose alleles were low in the donor database, such as HLA-A*68:02, and B*57:01. After avoiding donor-specific antibodies (DSA) matching, 102 of 209 platelet-compatible transfusions were effective, resulting in an effective rate of 48.8 %, which significantly improved the efficacy of platelet transfusion. The establishment of a platelet donor database is of great significance to improve the therapeutic effect of platelet transfusion in patients with hematologic disorder, and save blood resources, and it is also the premise and guarantee of precise platelet transfusion.

7.
Clin Med Insights Oncol ; 18: 11795549241236896, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38645894

RESUMO

By modifying immune cells, immunotherapy can activate immune response to establish long-term immune memory and prevent tumor recurrence. However, their effectiveness is largely constricted by the poor immunogenicity, immune escape, and immune tolerance of the tumor. This is related to the characteristics of the tumor itself, such as genome instability and mutation. The combination of various nanocarriers with tumor immunotherapy is beneficial for overcoming the shortcomings of traditional immunotherapy. Nanocarriers coated by cell membranes can extend blood circulation time, improve ability to evade immune clearance, and enhance targeting, thus significantly enhancing the efficacy of immunotherapy and showing great potential in tumor immunotherapy. This article reviews the application research progress of different types of cell membrane-modified nanocarriers in tumor immunotherapy, immunotherapy combination therapy, and tumor vaccines, and provides prospects for future research.

8.
J Agric Food Chem ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38648511

RESUMO

The filamentous fungus Penicillium sclerotiorum is significant in ecological and industrial domains due to its vast supply of secondary metabolites that have a diverse array of biological functions. We have gathered the metabolic potential and biological activities associated with P. sclerotiorum metabolites of various structures, based on extensive research of the latest literature. The review incorporated literature spanning from 2000 to 2023, drawing from reputable databases including Google Scholar, ScienceDirect, Scopus, and PubMed, among others. Ranging from azaphilones, meroterpenoids, polyketides, and peptides group exhibits fascinating potential pharmacological activities such as antimicrobial, anti-inflammatory, and antitumor effects, holding promise in pharmaceutical and industrial sectors. Additionally, P. sclerotiorum showcases biotechnological potential through the production of enzymes like ß-xylosidases, ß-d-glucosidase, and xylanases, pivotal in various industrial processes. This review underscores the need for further exploration into its genetic foundations and cultivation conditions to optimize the yield of valuable compounds and enzymes, highlighting the unexplored potential of P. sclerotiorum in diverse applications across industries.

9.
NPJ Vaccines ; 9(1): 64, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38509167

RESUMO

Despite prolonged surveillance and interventions, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses continue to pose a severe global health burden. Thus, we developed a chimpanzee adenovirus-based combination vaccine, AdC68-HATRBD, with dual specificity against SARS-CoV-2 and influenza virus. When used as a standalone vaccine, intranasal immunization with AdC68-HATRBD induced comprehensive and potent immune responses consisting of immunoglobin (Ig) G, mucosal IgA, neutralizing antibodies, and memory T cells, which protected the mice from BA.5.2 and pandemic H1N1 infections. When used as a heterologous booster, AdC68-HATRBD markedly improved the protective immune response of the licensed SARS-CoV-2 or influenza vaccine. Therefore, whether administered intranasally as a standalone or booster vaccine, this combination vaccine is a valuable strategy to enhance the overall vaccine efficacy by inducing robust systemic and mucosal immune responses, thereby conferring dual lines of immunological defenses for these two viruses.

10.
Biol Trace Elem Res ; 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38528285

RESUMO

Selenium nanoparticle (Nano-Se) is a new type of selenium supplement, which can improve the deficiency of traditional selenium supplements and maintain its physiological activity. Due to industrial pollution and irrational use in agriculture, Cu overexposure often occurs in animals and humans. In this study, Nano-Se alleviated CuSO4-induced testicular Cu accumulation, serum testosterone level decrease, testicular structural damage, and decrease in sperm quality. Meanwhile, Nano-Se reduced the ROS content in mice testis and enhanced the activities of T-AOC, GSH, SOD, and CAT compared with CuSO4 group. Furthermore, Nano-Se alleviated CuSO4-induced apoptosis by increasing the protein expression of Cleaved-Caspase-3, Cleaved-Caspase-9, Cleaved-Caspase-12, and Bax/Bcl-2 compared with CuSO4 group. At the same time, Nano-Se reversed CuSO4-induced increase of γ-H2AX protein expression in mice testis. In conclusion, this study confirmed that Nano-Se could alleviate oxidative stress, apoptosis, and DNA damage in the testis of mice with Cu excess, thereby protecting the spermatogenesis disorder induced by Cu.

11.
Biomed Opt Express ; 15(3): 1910-1925, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38495688

RESUMO

Diffuse optical tomography (DOT) employs near-infrared light to reveal the optical parameters of biological tissues. Due to the strong scattering of photons in tissues and the limited surface measurements, DOT reconstruction is severely ill-posed. The Levenberg-Marquardt (LM) is a popular iteration method for DOT, however, it is computationally expensive and its reconstruction accuracy needs improvement. In this study, we propose a neural model based iteration algorithm which combines the graph neural network with Levenberg-Marquardt (GNNLM), which utilizes a graph data structure to represent the finite element mesh. In order to verify the performance of the graph neural network, two GNN variants, namely graph convolutional neural network (GCN) and graph attention neural network (GAT) were employed in the experiments. The results showed that GCNLM performs best in the simulation experiments within the training data distribution. However, GATLM exhibits superior performance in the simulation experiments outside the training data distribution and real experiments with breast-like phantoms. It demonstrated that the GATLM trained with simulation data can generalize well to situations outside the training data distribution without transfer training. This offers the possibility to provide more accurate absorption coefficient distributions in clinical practice.

12.
J Agric Food Chem ; 72(12): 6500-6508, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38470347

RESUMO

Dipicolinic acid (DPA), a cyclic diacid, has garnered significant interest due to its potential applications in antimicrobial agents, antioxidants, chelating reagents, and polymer precursors. However, its natural bioproduction is limited since DPA is only accumulated in Bacillus and Clostridium species during sporulation. Thus, heterologous production by engineered strains is of paramount importance for developing a sustainable biological route for DPA production. Pseudomonas putida KT2440 has emerged as a promising host for the production of various chemicals thanks to its robustness, metabolic versatility, and genetic tractability. The dominant Entner-Doudoroff (ED) pathway for glucose metabolism in this strain offers an ideal route for DPA production due to the advantage of NADPH generation and the naturally balanced flux between glyceraldehyde-3-phosphate and pyruvate, which are both precursors for DPA synthesis. In this study, DPA production via the ED pathway was in silico designed in P. putida KT2440. The systematically engineered strain produced dipicolinate with a titer of 11.72 g/L from glucose in a 5 L fermentor. This approach not only provides a sustainable green route for DPA production but also expands our understanding of the metabolic potential of the ED pathway in P. putida KT2440.


Assuntos
Pseudomonas putida , Pseudomonas putida/genética , Metabolismo dos Carboidratos , Reatores Biológicos , Antioxidantes/metabolismo , Ácido Pirúvico/metabolismo , Engenharia Metabólica
13.
Biomed Pharmacother ; 174: 116479, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38537580

RESUMO

RNA methylation modifications are widespread in eukaryotes and prokaryotes, with N6-methyladenosine (m6A) the most common among them. Demethylases, including Fat mass and obesity associated gene (FTO) and AlkB homolog 5 (ALKBH5), are important in maintaining the balance between RNA methylation and demethylation. Recent studies have clearly shown that demethylases affect the biological functions of tumors by regulating their m6A levels. However, their effects are complicated, and even opposite results have appeared in different articles. Here, we summarize the complex regulatory networks of demethylases, including the most important and common pathways, to clarify the role of demethylases in tumors. In addition, we describe the relationships between demethylases and the tumor microenvironment, and introduce their regulatory mechanisms. Finally, we discuss evaluation of demethylases for tumor diagnosis and prognosis, as well as the clinical application of demethylase inhibitors, providing a strong basis for their large-scale clinical application in the future.

14.
Int J Mol Sci ; 25(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38542445

RESUMO

Panax ginseng C. A. Meyer (Ginseng) is one of the most used traditional Chinese herbal medicines, with its roots being used as the main common medicinal parts; its therapeutic potential has garnered significant attention. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) is a family of early auxin-responsive genes capable of regulating root development in plants through the auxin signaling pathway. In the present study, 84 Aux/IAA genes were identified from the ginseng genome and their complexity and diversity were determined through their protein domains, phylogenetic relationships, gene structures, and cis-acting element predictions. Phylogenetic analyses classified PgIAA into six subgroups, with members in the same group showing greater sequence similarity. Analyses of interspecific collinearity suggest that segmental duplications likely drove the evolution of PgIAA genes, followed by purifying selection. An analysis of cis-regulatory elements suggested that PgIAA family genes may be involved in the regulation of plant hormones. RNA-seq data show that the expression pattern of Aux/IAA genes in Ginseng is tissue-specific, and PgIAA02 and PgIAA36 are specifically highly expressed in lateral, fibrous, and arm roots, suggesting their potential function in root development. The PgIAA02 overexpression lines exhibited an inhibition of lateral root growth in Ginseng. In addition, yeast two-hybrid and subcellular localization experiments showed that PgIAA02 interacted with PgARF22/PgARF36 (ARF: auxin response factor) in the nucleus and participated in the biological process of root development. The above results lay the foundation for an in-depth study of Aux/IAA and provide preliminary information for further research on the role of the Aux/IAA gene family in the root development of Ginseng.


Assuntos
Panax , Proteínas de Plantas , Proteínas de Plantas/metabolismo , Filogenia , Panax/genética , Panax/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Regulação da Expressão Gênica de Plantas
15.
J Nutr Biochem ; 129: 109623, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38492819

RESUMO

Chemotherapy failure in colorectal cancer patients is the major cause of recurrence and poor prognosis. As a result, there is an urgent need to develop drugs that have a good chemotherapy effect while also being extremely safe. In this study, we found cafestol inhibited colon cancer growth and HCT116 proliferation in vivo and in vitro, and improved the composition of intestinal flora. Further metabolomic data showed that autophagy and AMPK pathways were involved in the process of cafestol's anti-colon cancer effects. The functional validation studies revealed that cafestol increased autophagy vesicles and LC3B-II levels. The autophagic flux induced by cafestol was prevented by using BafA1. The autophagy inhibitor 3-MA blocked the cafestol-induced increase in LC3B-II and cell proliferation inhibition. Then we found that cafestol induced the increased expressions of LKB1, AMPK, ULK1, p-LKB1, p-AMPK, and p-ULK1 proteins in vivo and in vitro. Using the siRNA targeted to the Lkb1 gene, the levels of AMPK, ULK1, and LC3B-II were suppressed under cafestol treatment. These results indicated that the effect of cafestol is through regulating LKB1/AMPK/ULK1 pathway-mediated autophagic death. Finally, a correlation matrix of the microbiome and autophagy-related proteins was conducted. We found that cafestol-induced autophagic protein expression was positively correlated with the beneficial intestinal bacteria (Muribaculaceae, Bacteroides, Prevotellacece, and Alloprevotella) and negatively correlated with the hazardous bacteria. Conclusions: This study found that cafestol inhibited colon cancer in vitro and in vivo by the mechanism that may be related to LKB1/AMPK/ULK1 pathway-mediated autophagic cell death and improved intestinal microenvironment.

16.
BMC Microbiol ; 24(1): 93, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38515035

RESUMO

Plant growth promoting microbe assisted phytoremediation is considered a more effective approach to rehabilitation than the single use of plants, but underlying mechanism is still unclear. In this study, we combined transcriptomic and physiological methods to explore the mechanism of plant growth promoting microbe Trichoderma citrinoviride HT-1 assisted phytoremediation of Cd contaminated water by Phragmites australis. The results show that the strain HT-1 significantly promoted P. australis growth, increased the photosynthetic rate, enhanced antioxidant enzyme activities. The chlorophyll content and the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were increased by 83.78%, 23.17%, 47.60%, 97.14% and 12.23% on average, and decreased the content of malondialdehyde (MDA) by 31.10%. At the same time, strain HT-1 improved the absorption and transport of Cd in P. australis, and the removal rate of Cd was increased by 7.56% on average. Transcriptome analysis showed that strain HT-1 induced significant up-regulated the expression of genes related to oxidative phosphorylation and ribosome pathways, and these upregulated genes promoted P. australis remediation efficiency and resistance to Cd stress. Our results provide a mechanistic understanding of plant growth promoting microbe assisted phytoremediation under Cd stress.


Assuntos
Cádmio , Hypocreales , Poluentes do Solo , Cádmio/análise , Biodegradação Ambiental , Água , Antioxidantes/metabolismo , Poaceae/metabolismo , Perfilação da Expressão Gênica , Poluentes do Solo/metabolismo
17.
Phytomedicine ; 128: 155349, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38522315

RESUMO

BACKGROUND: Trimethylamine N-oxide (TMAO), a metabolite produced by intestinal microbiota through metabolizing phosphatidylcholine, choline, l-carnitine and betaine in the diet, has been implicated in the pathogenesis of atherosclerosis (AS). Concurrently, dietary polyphenols have garnered attention for their potential to ameliorate obesity, diabetes and atherosclerosis primarily by modulating the intestinal microbial structure. Hickory (Carya cathayensis) nut, a polyphenol-rich food product favored for its palatability, emerges as a candidate for exploration. HYPOTHESIS/PURPOSE: The relationship between polyphenol of hickory nut and atherosclerosis prevention will be firstly clarified, providing theoretical basis for the discovery of natural products counteracting TMAO-induced AS process in hickory nut. STUDY DESIGN AND METHODS: Employing Enzyme-linked Immunosorbent Assay (ELISA) and histological examination of aortic samples, the effects of total polyphenol extract on obesity index, inflammatory index and pathological changes of atherosclerosis in C57BL/6 J mice fed with high-fat and high choline diet were evaluated. Further, the composition, abundance, and function of mouse gut microbiota were analyzed through 16srDNA sequencing. Concurrently, the levels of TMAO and the expression of key enzymes (CutC and FMO3) involved in its synthesis are quantified using ELISA, Western Blot and Real-Time Quantitative PCR (RT-qPCR). Additionally, targeted metabolomic profiling of the hickory nut polyphenol extract was conducted, accompanied by molecular docking simulations to predict interactions between candidate polyphenols and the CutC/FMO3 using Autodock Vina. Finally, the docking prediction were verified by microscale thermophoresis (MST) . RESULTS: Polyphenol extracts of hickory nut improved the index of obesity and inflammation, and alleviated the pathological changes of atherosclerosis in C57BL/6 J mice fed with high-fat and high-choline diet. Meanwhile, these polyphenol extracts also changed the composition and function of intestinal microbiota, and increased the abundance of microorganisms in mice. Notably, the abundance of intestinal microbiota endowed with CutC gene was significantly reduced, coherent with expression of CutC catalyzing TMA production. Moreover, polyphenol extracts also decreased the expression of FMO3 in the liver, contributing to the reduction of TMAO levels in serum. Furthermore, metabonomic profile analysis of these polyphenol extracts identified 647 kinds of polyphenols. Molecular docking predication further demonstrated that Casuariin and Cinnamtannin B2 had the most potential inhibition on the enzymatic activities of CutC or FMO3, respectively. Notably, MST analysis corroborated the potential for direct interaction between CutC enzyme and available polyphenols such as Corilagin, (-)-Gallocatechin gallate and Epigallocatechin gallate. CONCLUSION: Hickory polyphenol extract can mitigate HFD-induced AS by regulating intestinal microflora in murine models. In addition, TMA-FMO3-TMAO pathway may play a key role in this process. This research unveils, for the inaugural time, the complex interaction between hickory nut-derived polyphenols and gut microbial, providing novel insights into the role of dietary polyphenols in AS prevention.

18.
PLoS One ; 19(3): e0299046, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38446799

RESUMO

The agglomeration effect significantly influences firms' site selection. Manufacturing firms often exhibit intricate spatial co-location patterns that are indicative of agglomerations due to their reliance on material input and product output across various subdivisions of manufacture. In this study, we present an analytical approach employing the Q statistic and additive color mixing visualization to assess co-location patterns of manufacturing firms. We identified frequent pairs and triplets of manufacturing divisions, mapping them to reveal distinct categories: labor-intensive clusters, upstream/downstream industrial chains, and technology-spillover clusters. These agglomeration categories concentrate in different regions of the city. Policy implications are proposed to promote the upgrade of labor-intensive divisions, enhance the operational efficiency of upstream/downstream industrial chains, and reinforce the spillover effects of technology-intensive divisions.


Assuntos
Comércio , Trabalho de Parto , Gravidez , Feminino , Humanos , Indústrias , Políticas , Tecnologia
19.
Macromol Rapid Commun ; : e2400036, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453138

RESUMO

Preparation of materials that possess highly strong and tough properties simultaneously is a great challenge. Thermosetting resins as a type of widely used polymeric materials without synergistic strength and toughness limit their applications in some special fields. In this report, an effective strategy to prepare thermosetting resins with synergistic strength and toughness, is presented. In this method, the soft and rigid microspheres with dynamic hemiaminal bonds are fabricated first, followed by hot-pressing to crosslink at the interfaces. Specifically, the rigid or soft microspheres are prepared via precipitation polymerization. After hot-pressing, the resulting rigid-soft blending materials exhibit superior strength and toughness, simultaneously. As compared with the precursor rigid or soft materials, the toughness of the rigid-soft blending films (RSBFs) is improved to 240% and 2100%, respectively, while the strength is comparable to the rigid precursor. As compared with the traditional crushing, blending, and hot-pressing of rigid or soft materials to get the nonuniform materials, the strength and toughness of the RSBFs are improved to 168% and 255%, respectively. This approach holds significant promise for the fabrication of polymer thermosets with a unique combination of strength and toughness.

20.
J Org Chem ; 89(7): 4579-4594, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38506748

RESUMO

A palladium-catalyzed intermolecular [2 + 2 + 2] oxidative coupling-annulation of terminal alkenes and alkynes using copper(II) as the oxidant has been developed through direct C-C bond formation. These reactions provide effective access to multiaryl-substituted benzenes with high regioselectivity in the absence of any ligands. The features of this protocol are broad substrate scope, and high atom and step economy. The aggregation-induced emission properties of selected products were further investigated. These synthesized multiaryl-substituted benzenes may be worth exploring for further applications in the fields of advanced functional materials or drugs.

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