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1.
J Neurosci ; 44(23)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38697841

RESUMO

Interneurons in the medial prefrontal cortex (PFC) regulate local neural activity to influence cognitive, motivated, and emotional behaviors. Parvalbumin-expressing (PV+) interneurons are the primary mediators of thalamus-evoked feed-forward inhibition across the mouse cortex, including the anterior cingulate cortex, where they are engaged by inputs from the mediodorsal (MD) thalamus. In contrast, in the adjacent prelimbic (PL) cortex, we find that PV+ interneurons are scarce in the principal thalamorecipient layer 3 (L3), suggesting distinct mechanisms of inhibition. To identify the interneurons that mediate MD-evoked inhibition in PL, we combine slice physiology, optogenetics, and intersectional genetic tools in mice of both sexes. We find interneurons expressing cholecystokinin (CCK+) are abundant in L3 of PL, with cells exhibiting fast-spiking (fs) or non-fast-spiking (nfs) properties. MD inputs make stronger connections onto fs-CCK+ interneurons, driving them to fire more readily than nearby L3 pyramidal cells and other interneurons. CCK+ interneurons in turn make inhibitory, perisomatic connections onto L3 pyramidal cells, where they exhibit cannabinoid 1 receptor (CB1R) mediated modulation. Moreover, MD-evoked feed-forward inhibition, but not direct excitation, is also sensitive to CB1R modulation. Our findings indicate that CCK+ interneurons contribute to MD-evoked inhibition in PL, revealing a mechanism by which cannabinoids can modulate MD-PFC communication.


Assuntos
Colecistocinina , Interneurônios , Inibição Neural , Córtex Pré-Frontal , Animais , Interneurônios/fisiologia , Colecistocinina/metabolismo , Córtex Pré-Frontal/fisiologia , Camundongos , Masculino , Feminino , Inibição Neural/fisiologia , Tálamo/fisiologia , Camundongos Endogâmicos C57BL , Parvalbuminas/metabolismo , Camundongos Transgênicos , Vias Neurais/fisiologia , Optogenética
2.
Nano Lett ; 24(40): 12398-12405, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39324741

RESUMO

The five volt-class battery is one promising candidate of high energy density lithium-ion batteries. However, it suffers from limited electrochemical performance due to many problems, one of which is Al current collector corrosion. The corrosion greatly affects the electrochemical performance of batteries, so uncovering the Al corrosion mechanism and developing its protection strategy in the 5 V-class battery becomes important. Here, we experimentally realize a corrosion-resistant Al current collector via graphene protection. The experimental and theoretical calculation indicate that graphene can work as a physical barrier to inhibit direct contact between LiPF6-based electrolyte and an Al current collector, reducing the side reactions between Al current collector and HF originated from electrolyte. What is more, graphene increases the Al corrosion reaction potential, raising the difficulty of electrochemical corrosion. These effects improve the electrochemical performance of the 5 V-class battery, especially the rate performance and cycling stability. The work is beneficial for the development of a 5 V-class battery.

3.
J Biol Chem ; 299(3): 103021, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36791911

RESUMO

Tail tube assembly is an essential step in the lifecycle of long-tailed bacteriophages. Limited structural and biophysical information has impeded an understanding of assembly and stability of their long, flexible tail tubes. The hyperthermophilic phage P74-26 is particularly intriguing as it has the longest tail of any known virus (nearly 1 µm) and is the most thermostable known phage. Here, we use structures of the P74-26 tail tube along with an in vitro system for studying tube assembly kinetics to propose the first molecular model for the tail tube assembly of long-tailed phages. Our high-resolution cryo-EM structure provides insight into how the P74-26 phage assembles through flexible loops that fit into neighboring rings through tight "ball-and-socket"-like interactions. Guided by this structure, and in combination with mutational, light scattering, and molecular dynamics simulations data, we propose a model for the assembly of conserved tube-like structures across phage and other entities possessing tail tube-like proteins. We propose that formation of a full ring promotes the adoption of a tube elongation-competent conformation among the flexible loops and their corresponding sockets, which is further stabilized by an adjacent ring. Tail assembly is controlled by the cooperative interaction of dynamic intraring and interring contacts. Given the structural conservation among tail tube proteins and tail-like structures, our model can explain the mechanism of high-fidelity assembly of long, stable tubes.


Assuntos
Bacteriófagos , Caudovirales , Bacteriófagos/metabolismo , Caudovirales/metabolismo , Conformação Molecular , Modelos Moleculares , Proteínas da Cauda Viral/química
4.
Anal Chem ; 96(6): 2514-2523, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38289041

RESUMO

The urine bioassay method for transuranium nuclides (237Np, 239,240,241Pu, 241Am, and 244Cm) is needed to quickly assess the potential internal contamination in emergency situations. However, in the case that the analysis of multiple radionuclides is required in the same sample, time-consuming/tedious sequential analytical procedures using multiple chromatographic separation resins would have to be employed for the separation of every single radionuclide. In this work, a rapid method for the simultaneous determination of transuranium nuclides in urine was developed by using triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) combined with a single DGA resin column. The chemical behaviors of Np/Pu and Am/Cm on the DGA resin were consistent in 8-10 mol/L HNO3 and 0.005-0.02 mol/L NaNO2 when 242Pu and 243Am were selected as tracers for Np/Pu and Am/Cm yield monitoring. Based on their different reaction rates with O2, 237Np, 239,240,241Pu, 241Am, and 244Cm in the same solution were simultaneously measured by ICP-MS/MS in the same run. The elimination efficiency of 238U+ tailing (7.43 × 10-9), 238U1H16O2+/238U16O2+ (8.11 × 10-8) and cross contamination of 241Pu and 241Am (<1%) were achieved using 10.0 mL/min He-0.3 mL/min O2 even if the eluate was directly measured without any evaporation. The detection limits of transuranium nuclides were at the femtogram level, demonstrating the feasibility of ICP-MS/MS for simultaneous transuranic radionuclides urinalysis. The developed method was validated by analyzing the spiked urine samples.


Assuntos
Radioisótopos , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Radioisótopos/análise , Análise Espectral , Cromatografia , Urinálise
5.
Small ; 20(31): e2312087, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38441286

RESUMO

The LiCoO2 (LCO) cathode is foreseen for extensive commercial applications owing to its high specific capacity and stability. Therefore, there is considerable interest in further enhancing its specific capacity by increasing the charging voltage. However, single-crystal LCO suffers from a significant capacity degradation when charged to 4.5 V due to the irreversible phase transition and unstable structure. Herein, an ultra-small amount (0.5% wt. in the electrode) of multi-functional PIM-1 (a polymer with intrinsic microporosity) additive is utilized to prepare a kind of binder-free electrode. PIM-1 modulates the solvation structure of LiPF6 due to its unique structure, which helps to form a stable, robust, and inorganic-rich cathod-eelectrolyte interphase (CEI) film on the surface of LCO at a high voltage of 4.5 V. This reduces the irreversible phase transition of LCO, thereby enhancing the cyclic stability and improving the rate performance, providing new perspectives for the electrodes fabrication and improving LCO-based high-energy-density cathodes.

6.
J Chem Inf Model ; 64(12): 4835-4849, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38847742

RESUMO

The lymphocyte-specific protein tyrosine kinase (LCK) plays a crucial role in both T-cell development and activation. Dysregulation of LCK signaling has been demonstrated to drive the oncogenesis of T-cell acute lymphoblastic leukemia (T-ALL), thus providing a therapeutic target for leukemia treatment. In this study, we introduced a sophisticated virtual screening strategy combined with biological evaluations to discover potent LCK inhibitors. Our initial approach involved utilizing the PLANET algorithm to assess and contrast various scoring methodologies suitable for LCK inhibitor screening. After effectively evaluating PLANET, we progressed to devise a virtual screening workflow that synergistically combines the strengths of PLANET with the capabilities of Schrödinger's suite. This integrative strategy led to the efficient identification of four potential LCK inhibitors. Among them, compound 1232030-35-1 stood out as the most promising candidate with an IC50 of 0.43 nM. Further in vitro bioassays revealed that 1232030-35-1 exhibited robust antiproliferative effects on T-ALL cells, which was attributed to its ability to suppress the phosphorylations of key molecules in the LCK signaling pathway. More importantly, 1232030-35-1 treatment demonstrated profound in vivo antileukemia efficacy in a human T-ALL xenograft model. In addition, complementary molecular dynamics simulations provided deeper insight into the binding kinetics between 1232030-35-1 and LCK, highlighting the formation of a hydrogen bond with Met319. Collectively, our study established a robust and effective screening strategy that integrates AI-driven and conventional methodologies for the identification of LCK inhibitors, positioning 1232030-35-1 as a highly promising and novel drug-like candidate for potential applications in treating T-ALL.


Assuntos
Aprendizado Profundo , Proteína Tirosina Quinase p56(lck) Linfócito-Específica , Simulação de Acoplamento Molecular , Inibidores de Proteínas Quinases , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/antagonistas & inibidores , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Humanos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Animais , Descoberta de Drogas , Antineoplásicos/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Camundongos
7.
Phys Chem Chem Phys ; 26(6): 5704-5712, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38289691

RESUMO

In Fischer-Tropsch synthesis (FTS), the cobalt catalyst has higher C5+ and lower CH4 selectivity in the hcp phase than in the fcc phase. However, a detailed explanation of the intrinsic mechanism is still missing. The underlying reason was explored combining density functional theory, Wulff construction, and a particle-level descriptor based on the slab model of surfaces that are prevalent in the Wulff shape to provide single-particle level understanding. Using a particle-level indicator of the reaction rates, we have shown that it is more difficult to form CH4 on hcp-Co than on fcc-Co, due to the larger effective barrier difference of CH4 formation and C-C coupling on hcp-Co particles, which leads to the lower CH4 selectivity of hcp-Co in FTS. Among the exposed facets of fcc-Co, the (311) surface plays a pivotal role in promoting CH4 formation. The reduction of CH4 selectivity in cobalt-based FTS is achievable through phase engineering of Co from fcc to hcp or by tuning the temperature and size of the particles.

8.
Phys Chem Chem Phys ; 26(27): 18865-18870, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38946600

RESUMO

Using gas phase Fourier-transform microwave spectroscopy complemented by theoretical analysis, this study delivers a comprehensive depiction of the physical origin of the 'n → π* interaction' between CO2 and acrolein, one of the most reactive aldehydes. Three distinct isomers of the acrolein-CO2 complex, linked through a C⋯O tetrel bond (or n → π* interaction) and a C-H⋯O hydrogen bond, have been unambiguously identified in the pulsed jet. Relative intensity measurements allowed estimation on the population ratio of the three isomers to be T1/T2/C1 ≈ 25/5/1. Advanced theoretical analyses were employed to elucidate the intricacies of the noncovalent interactions within the examined complex. This study not only sheds light on the molecular underpinnings of n → π* interactions but also paves the way for future exploration in carbon dioxide capture and utilization, leveraging the fundamental principles uncovered in the study of acrolein-carbon dioxide interactions.

9.
Phys Chem Chem Phys ; 26(9): 7920-7930, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38376943

RESUMO

The transport properties of high-temperature silicate melts control magma flow and are crucial for a wide variety of industrial processes involving minerals. However, anomalous melt properties have been observed that cannot be explained by the traditional polymerization degree theory, which was derived based on quenched melts. Ab initio molecular dynamics (AIMD) simulations were conducted to investigate the flow mechanism of CaO-Al2O3-SiO2 melts under high temperature atmospheric conditions. By analyzing the dynamic structure of melted silicates and employing molecular orbital theory, we gained a fundamental understanding of the flow mechanism from a chemistry perspective. Transient tri-coordinated oxygen (TO) bonded with one Si and two Al atoms (SiOAl2) was found to be a pivotal intermediate in melt flow and atomic diffusion processes. Frequent chemical transition between TO in SiOAl2 and bridging oxygen (BO) dominated the fluidity of melted silicates. The presence of such transitions is facilitated by the unstable nature of [SiAlO2] 4-membered rings, which are susceptible to instability due to the intense repulsion between the O 2p lone pairs and the excessively bent O-Al-O angle. Additionally, the density of SiOAl2 type TO motif could serve as an indicator to determine the relationship between structure and fluidity. Our results challenge the traditional polymerization degree theory and suggest the need to reassess high-temperature liquid properties that govern processes in the Earth and industry by monitoring transient motifs.

10.
Acta Pharmacol Sin ; 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-39349767

RESUMO

Depressive disorders are a global mental health challenge that is closely linked to inflammation, especially in the post-COVID-19 era. The JAK-STAT pathway, which is primarily associated with inflammatory responses, is not fully characterized in the context of depressive disorders. Recently, a phase 3 retrospective cohort analysis heightened that the marketed JAK inhibitor tofacitinib is beyond immune diseases and has potential for preventing mood disorders. Inspired by these clinical facts, we investigated the role of the JAK-STAT signaling pathway in depression and comprehensively assessed the antidepressant effect of tofacitinib. We found that aberrant activation of the JAK-STAT pathway is highly conserved in the hippocampus of classical depressive mouse models: LPS-induced and chronic social defeat stress (CSDS)-induced depressive mice. Mechanistically, the JAK-STAT pathway mediates proinflammatory cytokine production and microgliosis, leading to synaptic defects in the hippocampus of both depressive models. Remarkably, the JAK inhibitor tofacitinib effectively reverses these phenomena, contributing to its antidepressant effect. These findings indicate that the JAK/STAT pathway could be implicated in depressive disorders, and suggest that the JAK inhibitor tofacitinib has a potential translational implication for preventing mood disorders far beyond its current indications.

11.
Plant Cell Rep ; 43(3): 67, 2024 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-38341832

RESUMO

KEY MESSAGE: In this study, genome-wide association studies combined with transcriptome data analysis were utilized to reveal potential candidate genes for stripe rust resistance in wheat, providing a basis for screening wheat varieties for stripe rust resistance. Wheat stripe rust, which is caused by the wheat stripe rust fungus (Puccinia striiformis f. sp. tritici, Pst) is one of the world's most devastating diseases of wheat. Genetic resistance is the most effective strategy for controlling diseases. Although wheat stripe rust resistance genes have been identified to date, only a few of them confer strong and broad-spectrum resistance. Here, the resistance of 335 wheat germplasm resources (mainly wheat landraces) from southwestern China to wheat stripe rust was evaluated at the adult stage. Combined genome-wide association study (GWAS) and weighted gene co-expression network analysis (WGCNA) based on RNA sequencing from stripe rust resistant accession Y0337 and susceptible accession Y0402, five candidate resistance genes to wheat stripe rust (TraesCS1B02G170200, TraesCS2D02G181000, TraesCS4B02G117200, TraesCS6A02G189300, and TraesCS3A02G122300) were identified. The transcription level analyses showed that these five genes were significantly differentially expressed between resistant and susceptible accessions post inoculation with Pst at different times. These candidate genes could be experimentally transformed to validate and manipulate fungal resistance, which is beneficial for the development of the wheat cultivars resistant to stripe rust.


Assuntos
Basidiomycota , Estudo de Associação Genômica Ampla , Triticum/genética , Triticum/microbiologia , Resistência à Doença/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , China
12.
Angew Chem Int Ed Engl ; 63(12): e202318747, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38270973

RESUMO

Metal atoms on the support serve as active sites for many heterogeneous catalysts. However, the active metal sites on the support are conventionally described as static, and the intermediates adsorbed on the support far away from the active metal sites cannot be transformed. Herein, we report the first example of operando mobile catalysis to promote catalytic efficiency by enhancing the collision probability between active sites and reactants or reaction intermediates. Specifically, ligand-coordinated Pt single atoms (isolated MeCpPt- species) are bonded on CeO2 and transformed into mobile MeCpPt(H)CO complexes during the reverse water gas shift reaction for operando mobile catalysis. This strategy enables the conversion of inert carbonate intermediates on the CeO2 support. A turnover frequency (TOF) of 6358 mol CO2 molPt -1 ⋅ h-1 and 99 % CO selectivity at 300 °C is obtained for reverse water gas shift reaction, dramatically higher than those of Pt catalysts reported in the literature. Operando mobile catalysis presents a promising strategy for designing high-efficiency heterogeneous catalysts for various chemical reactions and applications.

13.
J Phys Chem A ; 127(9): 2071-2080, 2023 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-36849363

RESUMO

Iron carbides have attracted increasing attention in recent years due to their enormous potential in catalytic fields, such as Fischer-Tropsch synthesis and the growth of carbon nanotubes. Theoretical calculations can provide a more thorough understanding of these reactions at the atomic scale. However, due to the extreme complexity of the active phases and surface structures of iron carbides at the operando conditions, calculations based on density functional theory (DFT) are too costly for realistically large models of iron carbide particles. Therefore, a cheap and efficient quantum mechanical simulation method with accuracy comparable to DFT is desired. In this work, we adopt the spin-polarized self-consistent charge density functional tight-binding (DFTB2) method for iron carbides by reparametrization of the repulsive part of the Fe-C interactions. To assess the performance of the improved parameters, the structural and electronic properties of iron carbide bulks and clusters obtained with DFTB2 method are compared with the previous experimental values and the results obtained with DFT approach. Calculated lattice parameters and density of states are close to DFT predictions. The benchmark results show that the proposed parametrization of Fe-C interactions provides transferable and balanced description of iron carbide systems. Therefore, spin-polarized DFTB2 is valued as an efficient and reliable method for the description of iron carbide systems.

14.
Bioorg Chem ; 139: 106683, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37379778

RESUMO

Inhibition of PARP is synthetic lethal with defects in BRCA, which provide effective targeted therapy strategy for BRCA mutation type of TNBC patients. However, approximately 80% of TNBC patients do not have BRCA mutations. Recent studies have shown that CDK4/6 inhibitors can increase the sensitivity of wild-type BRCA cells to PARP inhibitors. We designed a series of dual PARP and CDK6 inhibitors, and the most promising compound, P4i, showed good inhibitory activity against PARP1 and CDK6 and good inhibitory effects on MDA-MB-231 (IC50 = 1.96 µM), MDA-MB-468 (IC50 = 2.81 µM) and BT-549 (IC50 = 2.37 µM) cells with wild-type BRCA. Compared with Olaparib, the inhibition capacity of the three BRCA wild-type (MDA-MB-231, MDA-MB-468 and BT-549) cells was about 10-20 times higher, and even better than the combination of Olaparib and Palbociclib. As a novel PARP multifunctional molecule, it is a potential compound for the treatment of BRCA wild-type TNBC.


Assuntos
Inibidores de Poli(ADP-Ribose) Polimerases , Neoplasias de Mama Triplo Negativas , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Linhagem Celular Tumoral , Quinase 6 Dependente de Ciclina
15.
Proc Natl Acad Sci U S A ; 117(38): 23571-23580, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32907938

RESUMO

DNA replication requires the sliding clamp, a ring-shaped protein complex that encircles DNA, where it acts as an essential cofactor for DNA polymerases and other proteins. The sliding clamp needs to be opened and installed onto DNA by a clamp loader ATPase of the AAA+ family. The human clamp loader replication factor C (RFC) and sliding clamp proliferating cell nuclear antigen (PCNA) are both essential and play critical roles in several diseases. Despite decades of study, no structure of human RFC has been resolved. Here, we report the structure of human RFC bound to PCNA by cryogenic electron microscopy to an overall resolution of ∼3.4 Å. The active sites of RFC are fully bound to adenosine 5'-triphosphate (ATP) analogs, which is expected to induce opening of the sliding clamp. However, we observe the complex in a conformation before PCNA opening, with the clamp loader ATPase modules forming an overtwisted spiral that is incapable of binding DNA or hydrolyzing ATP. The autoinhibited conformation observed here has many similarities to a previous yeast RFC:PCNA crystal structure, suggesting that eukaryotic clamp loaders adopt a similar autoinhibited state early on in clamp loading. Our results point to a "limited change/induced fit" mechanism in which the clamp first opens, followed by DNA binding, inducing opening of the loader to release autoinhibition. The proposed change from an overtwisted to an active conformation reveals an additional regulatory mechanism for AAA+ ATPases. Finally, our structural analysis of disease mutations leads to a mechanistic explanation for the role of RFC in human health.


Assuntos
ATPases Associadas a Diversas Atividades Celulares , Replicação do DNA/fisiologia , Antígeno Nuclear de Célula em Proliferação , Proteína de Replicação C , ATPases Associadas a Diversas Atividades Celulares/química , ATPases Associadas a Diversas Atividades Celulares/metabolismo , Trifosfato de Adenosina/química , Trifosfato de Adenosina/metabolismo , Microscopia Crioeletrônica , Humanos , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/metabolismo , Antígeno Nuclear de Célula em Proliferação/ultraestrutura , Proteína de Replicação C/química , Proteína de Replicação C/metabolismo , Proteína de Replicação C/ultraestrutura
16.
Sci Technol Adv Mater ; 24(1): 2186690, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36926201

RESUMO

Biogenic collagen membranes (BCM) have been widely used in guided bone regeneration (GBR) owing to their biodegradability during tissue integration. However, their relatively high degradation rate and lack of pro-osteogenic properties limit their clinical outcomes. It is of great importance to endow BCM with tailored degradation as well as pro-osteogenic properties. In this study, a fluoride-modified polymer-induced liquid precursor (PILP) based biomineralization strategy was used to convert the collagen membrane from an organic phase to an apatite-based inorganic phase, thus achieving enhanced anti-degradation performance as well as osteogenesis. As a result, three phases of collagen membranes were prepared. The original BCM in the organic phase induced the mildest inflammatory response and was mostly degraded after 4 weeks. The organic-inorganic mixture phase of the collagen membrane evoked a prominent inflammatory response owing to the fluoride-containing amorphous calcium phosphate (F-ACP) nanoparticles, resulting in active angiogenesis and fibrous encapsulation, whereas the inorganic phase induced a mild inflammatory response and degraded the least owing to the transition of F-ACP particles into calcium phosphate with high crystallinity. Effective control of ACP is key to building novel apatite-based barrier membranes. The current results may pave the way for the development of advanced apatite-based membranes with enhanced barrier performances.

17.
Sensors (Basel) ; 23(13)2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37447757

RESUMO

With the progress of science and technology, artificial intelligence is widely used in various disciplines and has produced amazing results. The research of the target detection algorithm has significantly improved the performance and role of unmanned aerial vehicles (UAVs), and plays an irreplaceable role in preventing forest fires, evacuating crowded people, surveying and rescuing explorers. At this stage, the target detection algorithm deployed in UAVs has been applied to production and life, but making the detection accuracy higher and better adaptability is still the motivation for researchers to continue to study. In aerial images, due to the high shooting height, small size, low resolution and few features, it is difficult to be detected by conventional target detection algorithms. In this paper, the UN-YOLOv5s algorithm can solve the difficult problem of small target detection excellently. The more accurate small target detection (MASD) mechanism is used to greatly improve the detection accuracy of small and medium targets, The multi-scale feature fusion (MCF) path is combined to fuse the semantic information and location information of the image to improve the expression ability of the novel model. The new convolution SimAM residual (CSR) module is introduced to make the network more stable and focused. On the VisDrone dataset, the mean average precision (mAP) of UAV necessity you only look once v5s(UN-YOLOv5s) is 8.4% higher than that of the original algorithm. Compared with the same version, YOLOv5l, the mAP is increased by 2.2%, and the Giga Floating-point Operations Per Second (GFLOPs) is reduced by 65.3%. Compared with the same series of YOLOv3, the mAP is increased by 1.8%, and GFLOPs is reduced by 75.8%. Compared with the same series of YOLOv8s, the detection accuracy of the mAP is improved by 1.1%.


Assuntos
Algoritmos , Inteligência Artificial , Humanos , Motivação , Fotografação , Nações Unidas
18.
Int J Mol Sci ; 24(14)2023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37511190

RESUMO

Peri-implantitis requires clinical treatments comprised of mechanical and chemical debridement to remove bacterial biofilms. Bone regeneration on the titanium surface after debridement has been a topical issue of peri-implantitis treatments. Increasing evidence has revealed that the immune microenvironment plays a key role in regulating the bone regeneration process. However, it remains unclear what kind of immune microenvironment the titanium surface induces after debridement. In the study, model titanium surface after debridement was prepared via biofilm induction and mechanical and chemical debridement in vitro. Then, the macrophages and naïve CD4+ T lymphocytes were cultured on the titanium surface after debridement for immune microenvironment evaluation, with the original titanium surface as the control. Next, to regulate the immune microenvironment, 2-DG, a glycolysis inhibitor, was further incorporated to regulate macrophages and CD4+ T lymphocytes at the same time. Surface characterization results showed that the bacterial biofilms were completely removed, while the micro-morphology of titanium surface altered after debridement, and the element composition did not change. Compared with the original titanium disc, titanium surface after debridement can lead to the inflammatory differentiation of macrophages and CD4+ T lymphocytes. The percentage of M1 and Th17 inflammatory cells and the expression of their inflammatory factor genes are upregulated. However, 0.3 mmol of 2-DG can significantly reduce the inflammatory differentiation of both macrophages and CD4+ T lymphocytes and inhibit their expression of inflammatory genes. In conclusion, although bacterial biofilms were removed from titanium surface after debridement, the surface topography changes could still induce immune imbalance and form an inflammatory immune microenvironment. However, this inflammatory immune microenvironment can be effectively reversed by 2-DG in vitro, thus creating an immune microenvironment conducive to osteogenesis, which might provide a new perspective for future therapy of peri-implantitis.


Assuntos
Implantes Dentários , Peri-Implantite , Humanos , Peri-Implantite/terapia , Desbridamento , Titânio/química , Biofilmes , Regeneração Óssea , Propriedades de Superfície
19.
J Am Chem Soc ; 144(19): 8807-8817, 2022 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-35522220

RESUMO

Here, we describe the unexpected discovery of a Cu-catalyzed condensation polymerization reaction of propargylic electrophiles (CPPE) that transforms simple C3 building blocks into polydiynes of C6 repeating units. This reaction was achieved by a simple system composed of a copper acetylide initiator and an electron-rich phosphine ligand. Alkyne polymers (up to 33.8 kg/mol) were produced in good yields and exclusive regioselectivity with high functional group compatibility. Hydrogenation of the product afforded a new polyolefin-type backbone, while base-mediated isomerization led to a new type of dienyne-based electron-deficient conjugated polymer. Mechanistic studies revealed a new α-α selective Cu-catalyzed dimerization pathway of the C3 unit, followed by in situ organocopper-mediated chain-growth propagation. These insights not only provide an important understanding of the Cu-catalyzed CPPE of C3, C4, and C6 monomers in general but also lead to a significantly improved synthesis of polydiynes from simpler starting materials with handles for the incorporation of an α-end functional group.


Assuntos
Alcinos , Cobre , Catálise , Dimerização , Polimerização , Polímeros
20.
Small ; 18(17): e2106396, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35344277

RESUMO

Control of structural ordering in noble metals is very important for the exploration of their properties and applications, and thus it is highly desired to have an in-depth understanding of their structural transitions. Herein, through high-pressure treatment, the mutual transformations between crystalline and amorphous phases are achieved in Pd nanosheets (NSs) and nanoparticles (NPs). The amorphous domains in the amorphous/crystalline Pd NSs exhibit pressure-induced crystallization (PIC) phenomenon, which is considered as the preferred structural response of amorphous Pd under high pressure. On the contrary, in the spherical crystalline@amorphous core-shell Pd NPs, pressure-induced amorphization (PIA) is observed in the crystalline core, in which the amorphous-crystalline phase boundary acts as the initiation site for the collapse of crystalline structure. The distinct PIC and PIA phenomena in two different heterophase Pd nanostructures might originate from the different characteristics of Pd NSs and NPs, including morphology, amorphous-crystalline interface, and lattice parameter. This work not only provides insights into the phase transition mechanisms of amorphous/crystalline heterophase noble metal nanostructures, but also offers an alternative route for engineering noble metals with different phases.

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