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1.
Nat Commun ; 15(1): 7996, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39266508

RESUMEN

Advancements in human-engineered heart tissue have enhanced the understanding of cardiac cellular alteration. Nevertheless, a human model simulating pathological remodeling following myocardial infarction for therapeutic development remains essential. Here we develop an engineered model of myocardial repair that replicates the phased remodeling process, including hypoxic stress, fibrosis, and electrophysiological dysfunction. Transcriptomic analysis identifies nine critical signaling pathways related to cellular fate transitions, leading to the evaluation of seventeen modulators for their therapeutic potential in a mini-repair model. A scoring system quantitatively evaluates the restoration of abnormal electrophysiology, demonstrating that the phased combination of TGFß inhibitor SB431542, Rho kinase inhibitor Y27632, and WNT activator CHIR99021 yields enhanced functional restoration compared to single factor treatments in both engineered and mouse myocardial infarction model. This engineered heart tissue repair model effectively captures the phased remodeling following myocardial infarction, providing a crucial platform for discovering therapeutic targets for ischemic heart disease.


Asunto(s)
Dioxoles , Fibrosis , Infarto del Miocardio , Piridinas , Ingeniería de Tejidos , Animales , Infarto del Miocardio/patología , Infarto del Miocardio/terapia , Infarto del Miocardio/metabolismo , Infarto del Miocardio/genética , Ratones , Humanos , Piridinas/farmacología , Piridinas/uso terapéutico , Ingeniería de Tejidos/métodos , Dioxoles/farmacología , Dioxoles/uso terapéutico , Miocardio/patología , Miocardio/metabolismo , Pirimidinas/farmacología , Pirimidinas/uso terapéutico , Benzamidas/farmacología , Benzamidas/uso terapéutico , Modelos Animales de Enfermedad , Transducción de Señal , Masculino , Ratones Endogámicos C57BL , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Remodelación Ventricular/efectos de los fármacos , Factor de Crecimiento Transformador beta/metabolismo , Corazón/fisiopatología , Corazón/efectos de los fármacos , Amidas
2.
Carbohydr Polym ; 343: 122449, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39174089

RESUMEN

N-linked glycosylation is a ubiquitous protein post-translational modification in which aberrant glycan biosynthesis has been linked to severe conditions like cancer. Accurate qualitative and quantitative analysis of N-glycans are crucial for investigating their physiological functions. Owing to the intrinsic absence of chromophores and high polarity of the glycans, current detection methods are restricted to liquid chromatography and mass spectrometry. Herein, we describe three new imidazolium-based glycan tags: 2'GITag, 3'GITag, and 4'GITag, that significantly improve both the limit of detection and limit of quantification of derivatized oligosaccharides, in terms of fluorescence intensity and ionisation efficiency. Our top-performing derivatisation agent, 4'GITag, shifted the detection sensitivity range from high femtomole to sub-femtomole levels in ESI-MS compared to traditional glycan label, 2AB, enabling the identification of 24 N-glycans in mouse serum, including those bearing sialic acids. Additionally, 4'GITag stabilized Na-salt forms of sialic acids, simplifying the simultaneous analysis of neutral and negative charged N-glycans significantly, avoiding the need for complex derivatisation procedures typically required for the detection of sialylated species. Overall, the favorable performance of imidazolium tags in the derivatisation and sensitive profiling of glycans has the potential for labeling tissue or live cells to explore disease biomarkers and for developing new targeted therapeutic strategies.


Asunto(s)
Imidazoles , Polisacáridos , Espectrometría de Masa por Ionización de Electrospray , Animales , Polisacáridos/química , Polisacáridos/sangre , Ratones , Imidazoles/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Colorantes Fluorescentes/química , Límite de Detección , Glicosilación
3.
J Colloid Interface Sci ; 677(Pt B): 541-550, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39154446

RESUMEN

The advancement of interface engineering has demonstrated remarkable efficacy in overcoming the primary impediment associated with sluggish reaction kinetics in supercapacitor electrodes. In this investigation, we employed a facile co-precipitation method to synthesize NiCoMoO4/MXene heterostructures utilizing Ti3C2Tx MXene nanosheets as carriers. This heterostructure inhibits the restacking of MXene nanosheets and simultaneously enhances the exposure of electrochemically active sites in NiCoMoO4 nanorods, thereby mitigating the reduction in specific capacitance resulting from volumetric fluctuations. The NiCoMoO4/MXene electrode, possessing pseudo-capacitance properties, demonstrates an impressive level of specific capacitance, exceptional performance across various charging rates, and consistent behavior throughout repeated cycles. By optimizing the mass ratio, this electrode achieves a specific capacity of 1900 F/g under a current density of 1 A/g. Even after enduring 10,000 cycles at a significantly higher current density of 5 A/g, it still maintains an impressive retention rate of 94.73 %. Our density functional theory (DFT) calculations indicate that the enhanced electrochemical performance can be attributed to the improved electronic coupling within the NiCoMoO4/MXene heterostructure. The integration of NiCoMoO4/MXene cathode and activated carbon (AC) anode with an alkaline gel electrolyte containing potassium ferricyanide in flexible quasi-solid-state supercapacitors (FSSCs) results in exceptional electrochemical performance and flexibility. These FSSCs demonstrate a maximum energy density of 72.89 Wh kg-1 at a power density of 850 W kg-1, while maintaining an impressive power output of 16,780 W kg-1 with an energy density of 37.28 Wh kg-1. Based on these outstanding properties, it is evident that the NiCoMoO4/MXene heterojunction possesses significant advantages as electrode material for supercapacitors, and the fabricated FSSCs devices pave a new pathway for flexible electronic devices.

4.
J Adolesc ; 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39164952

RESUMEN

INTRODUCTION: Based on the Combined Cognitive Biases Hypothesis, the current study via two parallel studies aims to explore the potential mediating role of attention biases and attention control regarding the link between trait mindfulness and psychological stress in adolescents. METHODS: For Study 1, we collected self-reported data from 2123 Chinese adolescents (mean age = 15.6 years, SD = 2.37; 52.8% female) in four schools. The participants completed measures of trait mindfulness, perceived stress, and attention bias. Mediation analysis was employed to investigate the potential mediating effect of attention bias. In Study 2, 123 participants (mean age = 17.7 years, SD = 2.68; 41.46% female) completed the attention network task after inducing attention bias. Then, trait mindfulness and perceived stress were measured. Mediation analysis was employed to investigate the potential mediating effect of attention control (alerting, orienting, and conflict monitoring) under attention bias. RESULTS: Study 1 demonstrated a significant mediating effect of negative attention bias ([-0.13, -0.07], p < .05) but not positive attention bias in the relationship between trait mindfulness and psychological stress. Study 2 revealed that conflict monitoring in negative attention bias ([-0.41, -0.16], p < .05), rather than alerting and orienting in negative attention bias, showed a significant mediating effect on the association between trait mindfulness and psychological stress. CONCLUSIONS: Findings from the two studies suggest that conflict monitoring during negative attention bias may be the underlying mechanism through which trait mindfulness helps mitigate psychological stress in adolescents.

5.
Molecules ; 29(15)2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39124993

RESUMEN

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‱ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‱ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‱, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology.

6.
Environ Geochem Health ; 46(8): 274, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38958770

RESUMEN

Fluoride-enriched groundwater is a serious threat for groundwater supply around the world. The medium-low temperature fluoride-enriched geothermal groundwater resource is widely distributed in the circum-Wugongshan area. And the fluoride concentration of all geothermal samples exceeds the WHO permissible limit of 1.5 mg/L. The Self-Organizing Map method, hydrochemical and isotopic analysis are used to decipher the driving factors and genetic mechanism of fluoride-enriched geothermal groundwater. A total of 19 samples collected from the circum-Wugongshan geothermal belt are divided into four clusters by the self-organizing map. Cluster I, Cluster II, Cluster III, and Cluster IV represent the geothermal groundwater with the different degree of fluoride concentration pollution, the different hydrochemical type, and the physicochemical characteristic. The high F- concentration geothermal groundwater is characterized by HCO3-Na with alkalinity environment. The δD and δ18O values indicate that the geothermal groundwater origins from the atmospheric precipitation with the recharge elevation of 1000-2100 m. The dissolution of fluoride-bearing minerals is the main source of fluoride ions in geothermal water. Moreover, groundwater fluoride enrichment is also facilitated by water-rock interaction, cation exchange and alkaline environment. Additionally, the health risk assessment result reveals that the fluorine-enriched geothermal groundwater in the western part of Wugongshan area poses a more serious threat to human health than that of eastern part. The fluoride health risks of geothermal groundwater for different group show differentiation, 100% for children, 94.74% for adult females, and 68.42% for adult males, respectively. Compared with adult females and adult males, children faced the greatest health risks. The results of this study provide scientific evaluation for the utilization of geothermal groundwater and the protection of human health around the Wugongshan area.


Asunto(s)
Fluoruros , Agua Subterránea , Contaminantes Químicos del Agua , Agua Subterránea/química , Fluoruros/análisis , China , Humanos , Medición de Riesgo , Contaminantes Químicos del Agua/análisis , Femenino , Masculino , Niño , Monitoreo del Ambiente , Adulto , Preescolar , Adolescente , Adulto Joven , Lactante , Frío , Manantiales de Aguas Termales/química
7.
Animals (Basel) ; 14(13)2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38998104

RESUMEN

The fat deposition of different adipose tissues is widely recognized as correlated, with distinct effects on meat quality traits and reproductive performance in poultry. In this study, we utilized lipidomics and transcriptomics analyses to investigate the heterogeneity and regulators of intramuscular fat (IMF), abdominal fat (AF), and subcutaneous fat (SF) in geese. Lipidomic profiling revealed 165, 129, and 77 differential lipid molecules (DLMs) between AF vs. IMF, SF vs. IMF, and SF vs. AF, respectively, with 47 common DLMs identified between AF vs. IMF and SF vs. IMF. Transcriptomic analysis identified 3369, 5758, and 131 differentially expressed genes (DEGs) between AF vs. IMF, SF vs. IMF, and SF vs. AF, respectively, with 2510 common DEGs identified between AF vs. IMF and SF vs. IMF. The KEGG results indicate that DLMs were predominantly enriched in glycerophospholipid and glycerolipid metabolism pathways, while DEGs were primarily enriched in metabolic pathways. Pearson correlation analysis identified FABP4, LPL, PLCB1, DSE, and PDE5A as potential factors influencing fat deposition. This study elucidates the heterogeneity and regulatory factors of different adipose tissues in geese, offering new insights for targeted improvements in goose meat quality and production efficiency.

8.
Viruses ; 16(7)2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39066330

RESUMEN

Avian leukosis viruses (ALVs) include a group of avian retroviruses primarily associated with neoplastic diseases in poultry, commonly referred to as avian leukosis. Belonging to different subgroups based on their envelope properties, ALV subgroups A, B, and J (ALV-A, ALV-B, and ALV-J) are the most widespread in poultry populations. Early identification and removal of virus-shedding birds from infected flocks are essential for the ALVs' eradication. Therefore, the development of rapid, accurate, simple-to-use, and cost effective on-site diagnostic methods for the detection of ALV subgroups is very important. Cas13a, an RNA-guided RNA endonuclease that cleaves target single-stranded RNA, also exhibits non-specific endonuclease activity on any bystander RNA in close proximity. The distinct trans-cleavage activity of Cas13 has been exploited in the molecular diagnosis of multiple pathogens including several viruses. Here, we describe the development and application of a highly sensitive Cas13a-based molecular test for the specific detection of proviral DNA of ALV-A, B, and J subgroups. Prokaryotically expressed LwaCas13a, purified through ion exchange and size-exclusion chromatography, was combined with recombinase polymerase amplification (RPA) and T7 transcription to establish the SHERLOCK (specific high-sensitivity enzymatic reporter unlocking) molecular detection system for the detection of proviral DNA of ALV-A/B/J subgroups. This novel method that needs less sample input with a short turnaround time is based on isothermal detection at 37 °C with a color-based lateral flow readout. The detection limit of the assay for ALV-A/B/J subgroups was 50 copies with no cross reactivity with ALV-C/D/E subgroups and other avian oncogenic viruses such as reticuloendotheliosis virus (REV) and Marek's disease virus (MDV). The development and evaluation of a highly sensitive and specific visual method of detection of ALV-A/B/J nucleic acids using CRISPR-Cas13a described here will help in ALV detection in eradication programs.


Asunto(s)
Virus de la Leucosis Aviar , Leucosis Aviar , Sistemas CRISPR-Cas , ADN Viral , Provirus , Virus de la Leucosis Aviar/genética , Virus de la Leucosis Aviar/aislamiento & purificación , Virus de la Leucosis Aviar/clasificación , Animales , Provirus/genética , Provirus/aislamiento & purificación , Leucosis Aviar/virología , Leucosis Aviar/diagnóstico , ADN Viral/genética , Enfermedades de las Aves de Corral/virología , Enfermedades de las Aves de Corral/diagnóstico , Pollos/virología , Sensibilidad y Especificidad , Proteínas Asociadas a CRISPR/genética , Proteínas Asociadas a CRISPR/metabolismo
9.
J Org Chem ; 89(12): 8334-8341, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38860473

RESUMEN

Here, a Cu2(OH)2CO3-catalyzed hydroboration reaction of 1,1-disubstituted α,ß-unsaturated compounds has been developed. The reaction was carried out using water as a solvent at room temperature except for N-monosubstituted α,ß-unsaturated amides. This method is applicable to diverse 1,1-disubstituted α,ß-unsaturated ketones, esters, and amides, showing excellent reactivity (up to 98% yield). Gram-scale experiments and functional group transformations further demonstrated the practicality of this method.

10.
Artículo en Inglés | MEDLINE | ID: mdl-38904855

RESUMEN

Drawing on the stressor-perception-coping-response model of stress, this study examined the associations between negative life events, present-moment awareness, problem-solving, and perceived stress among rural adolescents, focusing specifically on gender differences. Using a cross-sectional design, 3519 Chinese rural adolescents completed measures assessing negative life events, present-moment awareness, problem-solving, and perceived stress. Structural equation modeling was employed to examine the hypothesized serial mediation model. The results revealed a positive association between negative life events and perceived stress in rural adolescents, which was serially mediated by present-moment awareness and problem-solving. Furthermore, significant gender differences were observed. Specifically, girls exhibited larger effects than boys in the overall effect of negative life events on perceived stress, the indirect effect of present-moment awareness, and the serial mediating effect. These findings suggest that present-moment awareness and problem-solving may serve as crucial mechanisms for understanding rural adolescents' perceived stress in response to negative life events, particularly among female rural adolescents.

11.
Tumour Virus Res ; 18: 200286, 2024 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-38914377

RESUMEN

In the past decade, research has demonstrated that viral miRNAs encoded by a number of viral genomes, particularly by most of the herpesvirus including Marek's disease virus (MDV), play important regulatory roles in viral infection, replication, and regulation of tumorigenesis. As macrovesicles in cells, exosomes can deliver viral miRNAs and exert gene regulatory functions. Whether the exosomes play a role in the replication, pathogenesis/tumorigenesis of avian herpesviruses such as oncogenic Marek's disease virus (MDV) remains unclear. Herein we extracted and identified the exosomes from MDV-transformed T cell line MSB-1 and demonstrated high abundance of MDV-1 miRNA expression. Using dual luciferase-based reporter assay, we also demonstrated that the exosomes derived from MSB-1 can deliver functional miRNA successfully into primary chicken embryo fibroblasts. These findings provide new insights into the role of exosomes and the mechanisms of how virus-encoded miRNA function in MDV latency/activation switching, viral replication, pathogenesis and/or tumorigenesis.

13.
World J Gastroenterol ; 30(19): 2564-2574, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38817663

RESUMEN

BACKGROUND: Cell division cyclin 25C (CDC25C) is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research has shown that CDC25C could be a potential therapeutic target for cancers, particularly for hepatocellular carcinoma (HCC). However, the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood. AIM: To explore the impact of CDC25C on cell proliferation and apoptosis, as well as its regulatory mechanisms in HCC development. METHODS: Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences (LV-CDC25C shRNA) to knock down CDC25C. Subsequently, a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo. Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays, respectively. The expression of endoplasmic reticulum (ER) stress-related molecules (glucose-regulated protein 78, X-box binding protein-1, and C/EBP homologous protein) was measured in both cells and subcutaneous xenografts using quantitative real-time PCR (qRT-PCR) and western blotting. Additionally, apoptosis was investigated using flow cytometry, qRT-PCR, and western blotting. RESULTS: CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction. A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice. CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response, ultimately promoting ER stress-induced apoptosis in HCC cells. CONCLUSION: The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.


Asunto(s)
Carcinogénesis , Carcinoma Hepatocelular , Estrés del Retículo Endoplásmico , Neoplasias Hepáticas , Fosfatasas cdc25 , Animales , Humanos , Masculino , Ratones , Apoptosis , Carcinogénesis/genética , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Fosfatasas cdc25/metabolismo , Fosfatasas cdc25/genética , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Ratones Endogámicos C57BL , ARN Interferente Pequeño/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
14.
Int J Biol Macromol ; 268(Pt 1): 131205, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38643922

RESUMEN

A series of new kind green cellulose-supported bimetallic TiO2/Cu2O (Cell@TiO2/Cu2O) catalytic materials were obtained by in-situ reduction method employing cellulose as the carrier. The effects of metal percentage composition on the morphology and construction of the catalytic materials were systematically investigated. The Cell@TiO2/Cu2O were characterized by FT-IR, TG, XPS, SEM, TEM, EDS, and the element content was obtained by elemental analysis. Then, the achieved catalytic materials were applied to the chiral borylation reaction of α,ß-unsaturated compounds, including nitrile compounds, esters, and α,ß-unsaturated ketones. Remarkably, this approach provides an efficient strategy to gain an important class of chiral organic boron compounds with target chiral products in high yields as well as enantioselectivities. Besides, the Cell@TiO2/Cu2O could be easily recycled and effectively reused. This work constructed bimetallic TiO2/Cu2O on cellulose as a newly catalyst to obtain chiral boron compounds in aqueous phase.


Asunto(s)
Celulosa , Cobre , Titanio , Titanio/química , Cobre/química , Celulosa/química , Catálisis , Agua/química , Compuestos de Boro/química
15.
FEBS Lett ; 598(11): 1402-1410, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38589226

RESUMEN

Overactivation of the epidermal growth factor receptor (EGFR) is critical for the development of multiple cancers. Previous studies have shown that the cell membrane is a key regulator of EGFR kinase activity through its interaction with the EGFR juxtamembrane domain (JM). However, the lipid recognition specificity of EGFR-JM and its interaction details remain unclear. Using lipid strip and liposome pulldown assays, we showed that EGFR-JM could specifically interact with PI(4,5)P2-or phosphatidylserine-containing membranes. We further characterized the JM-membrane interaction using NMR-titration-based chemical shift perturbation and paramagnetic relaxation enhancement analyses, and found that residues I649 - L659 comprised the membrane-binding site. Furthermore, the membrane-binding region contains the predicted dimerization motif of JM, 655LRRLL659, suggesting that membrane binding may affect JM dimerization and, therefore, regulate kinase activation.


Asunto(s)
Membrana Celular , Receptores ErbB , Fosfatidilserinas , Unión Proteica , Dominios Proteicos , Receptores ErbB/metabolismo , Receptores ErbB/química , Receptores ErbB/genética , Humanos , Membrana Celular/metabolismo , Fosfatidilserinas/metabolismo , Fosfatidilserinas/química , Sitios de Unión , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositol 4,5-Difosfato/química , Liposomas/metabolismo , Liposomas/química , Multimerización de Proteína , Secuencia de Aminoácidos
16.
Plants (Basel) ; 13(7)2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38611476

RESUMEN

To explore the population structures and dynamics of Rhododendron shrub communities at different stages of succession in northwest Guizhou, China, this study examined the populations of Rhododendron annae and Rhododendron irroratum shrub with two different stages. A space-for-time substitution was employed to establish the diameter class/height structures, static life tables, and survival/mortality rate/disappearance rate curves of both Rhododendron populations with different orders of succession. Their structural and quantitative dynamics were analyzed, and their development trends were predicted. The results showed that, quantitatively, the populations of R. annae and R. irroratum in the two Rhododendron communities with different orders of succession were dominated by age classes one, two, and three as well as height classes i, ii, and iii. The number of Rhododendron plants at the three age classes and the three height classes accounted for 97.61-100% of the total. The quantitative dynamic indices of R. annae and R. irroratum were both greater than 0, with and without considering external interference. In terms of age class and height structures, both Rhododendron populations were expanding populations, presenting "inverted-J-shaped" and irregular pyramid patterns. There was a sufficient number of young individuals, but few or no old individuals. Both survival curves of the populations of R. annae and R. irroratum in the two Rhododendron communities with different orders of succession belonged to the Deevy-II type. In the late stage of succession, the mortality curves and disappearance curves of both Rhododendron populations in these communities presented a trend of increasing first and then decreasing with increasing age class. This result indicates that at each age class, R. annae and R. irroratum showed a trend of gradual increase after two, four, and six years. In brief, the populations of R. annae and R. irroratum have rich reserves of seedlings and saplings, but high mortality and disappearance rates. In this context, it is necessary to reduce human interference and implement targeted conservation measures to promote the natural renewal of Rhododendron populations.

17.
J Phys Chem Lett ; 15(10): 2708-2714, 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38427973

RESUMEN

CPEB3 ribozyme is a self-cleaving RNA that occurs naturally in mammals and requires divalent metal ions for efficient activity. Ribozymes exhibit preferences for specific metal ions, but the exact differences in the catalytic mechanisms of various metal ions on the CPEB3 ribozyme remain unclear. Our findings reveal that Mn2+ functions as a more effective cofactor for CPEB3 ribozyme catalysis compared to Mg2+, as confirmed by its stronger binding affinity to CPEB3 by EPR. Cleavage assays of CPEB3 mutants and molecular docking analyses further showed that excessive Mn2+ ions can bind to a second binding site near the catalytic site, hindering CPEB3 catalytic efficiency and contributing to the Mn2+ bell-shaped curve. These results implicate a pivotal role for the local nucleobase-Mn2+ interactions in facilitating RNA folding and modulating the directed attack of nucleophilic reagents. Our study provides new insights and experimental evidence for exploring the divalent cation dependent cleavage mechanism of the CPEB3 ribozyme.


Asunto(s)
ARN Catalítico , Animales , ARN Catalítico/química , Magnesio/química , Simulación del Acoplamiento Molecular , Conformación de Ácido Nucleico , Cationes Bivalentes/metabolismo , Catálisis , Mamíferos/genética , Mamíferos/metabolismo
18.
Chem Soc Rev ; 53(7): 3384-3456, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38411207

RESUMEN

The scientific community has witnessed extensive developments and applications of organoboron compounds as synthetic elements and metal-free catalysts for the construction of small molecules, macromolecules, and functional materials over the last two decades. This review highlights the achievements of organoboron-mediated polymerizations in the past several decades alongside the mechanisms underlying these transformations from the standpoint of the polymerization mode. Emphasis is placed on free radical polymerization, Lewis pair polymerization, ionic (cationic and anionic) polymerization, and polyhomologation. Herein, alkylborane/O2 initiating systems mediate the radical polymerization under ambient conditions in a controlled/living manner by careful optimization of the alkylborane structure or additives; when combined with Lewis bases, the selected organoboron compounds can mediate the Lewis pair polymerization of polar monomers; the bicomponent organoboron-based Lewis pairs and bifunctional organoboron-onium catalysts catalyze ring opening (co)polymerization of cyclic monomers (with heteroallenes, such as epoxides, CO2, CO, COS, CS2, episulfides, anhydrides, and isocyanates) with well-defined structures and high reactivities; and organoboranes initiate the polyhomologation of sulfur ylides and arsonium ylides providing functional polyethylene with different topologies. The topological structures of the produced polymers via these organoboron-mediated polymerizations are also presented in this review mainly including linear polymers, block copolymers, cyclic polymers, and graft polymers. We hope the summary and understanding of how organoboron compounds mediate polymerizations can inspire chemists to apply these principles in the design of more advanced organoboron compounds, which may be beneficial for the polymer chemistry community and organometallics/organocatalysis community.

19.
Sci Total Environ ; 918: 170351, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38307288

RESUMEN

Iron and manganese (hydrogen) oxides (IMHOs) exhibit excellent redox capabilities for environmental pollutants and are commonly used in situ chemical oxidation (ISCO) technologies for the degradation of organic pollutants. However, the coexisting dissolved organic matter (DOMs) in surface environments would influence the degradation behavior and fate of organic pollutants in IMHOs-based ISCO. This review has summarized the interactions and mechanisms between DOMs and IMHOs, as well as the properties of DOM-IMHOs complexes. Importantly, the promotion or inhibition impact of DOM was discussed from three perspectives. First, the presence of DOMs may hinder the accessibility of active sites on IMHOs, thus reducing their efficiency in degrading organic pollutants. The formation of compounds between DOMs and IMHOs alters their stability and activity in the degradation process. Second, the presence of DOMs may also affect the generation and transport of active species, thereby influencing the oxidative degradation process of organic pollutants. Third, specific components within DOMs also participate and affect the degradation pathways and rates. A comprehensive understanding of the interaction between DOMs and IMHOs helps to better understand and predict the degradation process of organic pollutants mediated by IMHOs in real environmental conditions and contributes to the further development and application of IMHO-mediated ISCO technology.

20.
Phys Chem Chem Phys ; 26(9): 7475-7481, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38353594

RESUMEN

Theory and experiment have revealed that spin-orbit coupling (SOC) strongly depends on the relativistic effect in topological insulators (TIs), while the influence of orbitals is always ignored. Herein, we provide a direct way of controlling effective SOC with the help of orbital effects, reducing the dependence on elements. Taking 5d W2CO2 and 4d Mo2CO2 MXenes as a specific example, we predict that by decreasing the hybridization strength of W atoms with C or O atoms in 2D W2CO2, the nontrivial bandgaps at the Γ-point are directly enhanced. The weak hybridization of W atoms with ligand elements enhances the electron localization of degenerate d-orbitals of three groups under the triangular prism crystal field, inducing stronger on-site Coulomb repulsion that enhances orbital polarization as well as boosts the SOC effect. Meanwhile, similar results have also been observed in 4d Mo2CO2. This implies that the orbital effects are an efficient and straightforward way to control the nontrivial bandgap in 2D MXene TIs. Our work not only provides an alternative perspective on designing large nontrivial bandgaps but also brings a possibility to control the SOC effect for TI devices.

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