Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 290
Filtrar
1.
J Mater Chem B ; 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39282850

RESUMEN

Depression, a prevalent mental illness, is intricately linked with the neurotransmitters in the brain, while serotonin as a crucial regulator of mood, energy levels, and memory, has been implicated in depression. So, the release of serotonin by serotonergic neurons plays a significant role in the development of depression. Notably, the foremost marker of oxidative stress, hydrogen peroxide (H2O2), can interfere with the functioning of serotonergic neurons and potentially contribute to depression. Investigating the impact of H2O2 on serotonergic neurons could offer valuable insights into the mechanisms underlying depression. However, there have been no effective tools for selectively imaging H2O2 in these neurons so far. To address this gap, we created a small molecular fluorescent probe, PF-H2O2, designed specifically for imaging H2O2 in serotonergic neurons under oxidative stress. PF-H2O2 exerts excellent serotonergic neuron-targetability and notable selectivity for H2O2. Furthermore, we discovered increased H2O2 in serotonergic neurons of mice with depressive symptoms. Altogether, this endeavour unveils a pioneering tool for exploring pathophysiology linked to serotonergic neuronal dysfunction.

2.
Front Genet ; 15: 1413500, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39156961

RESUMEN

The most prevalent hip disease in neonates is developmental dysplasia of the hip (DDH). A timely and accurate diagnosis is required to provide the most effective treatment for pediatric patients with DDH. Heredity and gene variation have been the subject of increased attention and research worldwide as one of the factors contributing to the pathogenesis of DDH. Genome-wide association studies (GWAS), genome-wide linkage analyses (GWLA), and exome sequencing (ES) have identified variants in numerous genes and single-nucleotide polymorphisms (SNPs) as being associated with susceptibility to DDH in sporadic and DDH family patients. Furthermore, the DDH phenotype can be observed in animal models that exhibit susceptibility genes or loci, including variants in CX3CR1, KANSL1, and GDF5. The dentification of noncoding RNAs and de novo gene variants in patients with DDH-related syndrome has enhanced our understanding of the genes implicated in DDH. This article reviews the most recent molecular mechanisms and genetic factors that contribute to DDH.

3.
Cell Death Discov ; 10(1): 368, 2024 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-39155286

RESUMEN

Autophagosome-lysosome fusion defects play a critical role in driving autolysosomal dysfunction, leading to autophagic/lysosomal impairment in neurons following ischemic stroke. However, the mechanisms hindering autophagosome-lysosome fusion remain unclear. Soluble N-ethylmaleimide-sensitive factor (NSF) is an essential ATPase to reactivate STX17 and VAMP8, which are the paired molecules to mediate fusion between autophagosomes and lysosomes. However, NSF is frequently inactivated to inhibit the reactivation of STX17 and VAMP8 in ischemic neurons. Herein, we investigated whether autophagosome-lysosome fusion could be facilitated to alleviate autophagic/lysosomal impairment in ischemic neurons by over-expressing NSF. Rat model of middle cerebral artery occlusion (MCAO) and HT22 neuron ischemia model of oxygen-glucose deprivation (OGD) were prepared, respectively. The results demonstrated that NSF activity was significantly suppressed, accompanied by reduced expressions of STX17 and VAMP8 in penumbral neurons 48 h post-MCAO and in HT22 neurons 2 h post-OGD. Moreover, the attenuated autolysosome formation accompanied by autophagic/lysosomal dysfunction was observed. Thereafter, NSF activity in HT22 neurons was altered by over-expression and siRNA knockdown, respectively. After transfection with recombinant NSF-overexpressing lentiviruses, both STX17 and VAMP8 expressions were concurrently elevated to boost autophagosome-lysosome fusion, as shown by enhanced immunofluorescence intensity co-staining with LC3 and LAMP-1. Consequently, the OGD-created autophagic/lysosomal dysfunction was prominently ameliorated, as reflected by augmented autolysosomal functions and decreased autophagic substrates. By contrast, NSF knockdown conversely aggravated the autophagic/lysosomal impairment, and thereby exacerbated neurological damage. Our study indicates that NSF over-expression induces neuroprotection against ischemic neuronal injury by restoring autophagic/lysosomal dysfunction via the facilitation of autophagosome-lysosome fusion. Over-expression of NSF promotes fusion by reactivating STX17 and VAMP8. Black arrows represent the pathological process after cerebral ischemia, green arrows represent the mechanism of remission after NSF over-expression, and red arrows represent the effect on the pathological process after NSF knockdown.

4.
Chemistry ; : e202402875, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39148303

RESUMEN

Highly enantioselective Rh-catalyzed allylic substitution of the racemic branched allylic substrates with 2-fluoromalonate was realized enabled by a novel chiral sulfoxide-imine-olefin ligand under mild reaction conditions. The utilization of CuSO4 is beneficial for improving the enantioselectivity. Notably, the chiral fluoro-containing allyl products can be employed in a selective cyclic esterification to form chiral α-fluorolactone bearing vicinal stereogenic centers.

5.
Angew Chem Int Ed Engl ; : e202410721, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39212245

RESUMEN

Cesium-based inorganic perovskites have emerged as promising light-harvesting materials for perovskite solar cells (PSCs) due to their promising thermal- and photo-stability. However, obstacles to commercialization remain regarding their phase instability. In this work, we report a facile and effective strategy to regulate the surface compressive strain via in-situ surface reaction to stabilize CsPbI3 perovskite. The use of a chelating ligand with a molecular configuration closely matching the integer multiples of the unit cell lattice parameters of CsPbI3 induces compressive strain at the surface of CsPbI3. The chemical bonding and strain modulation synergistically not only passivate film defects, but also inhibit perovskite phase degradation, thus significantly improving the intrinsic stability of inorganic perovskite. Consequently, enhanced power conversion efficiency (PCE) of 21.0% and 18.6% were respectively achieved in 0.16-cm2 lab-scale devices and 25.3-cm2 solar modules. Further, surface reaction enables PSCs with enhanced thermal and operational stability; these devices retain over 95% of their initial PCE after damp-heat tests (i.e., in 85 ℃ and 85% R.H. air) for 2000 h, and remain 99% of their initial PCE after operating for 2000 h, representing one of the most stable inorganic PSCs reported so far.

6.
Mol Plant ; 17(9): 1423-1438, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39095994

RESUMEN

Understanding how maize (Zea mays) responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties. Despite extensive utilization of the genome-wide association study (GWAS) approach for exploring favorable natural alleles associated with maize cold tolerance, few studies have successfully identified candidate genes that contribute to maize cold tolerance. In this study, we used a diverse panel of inbred maize lines collected from different germplasm sources to perform a GWAS on variations in the relative injured area of maize true leaves during cold stress-a trait very closely correlated with maize cold tolerance. We identified HSF21, which encodes a B-class heat shock transcription factor (HSF) that positively regulates cold tolerance at both the seedling and germination stages. Natural variations in the promoter of the cold-tolerant HSF21Hap1 allele led to increased HSF21 expression under cold stress by inhibiting binding of the basic leucine zipper bZIP68 transcription factor, a negative regulator of cold tolerance. By integrating transcriptome deep sequencing, DNA affinity purification sequencing, and targeted lipidomic analysis, we revealed the function of HSF21 in regulating lipid metabolism homeostasis to modulate cold tolerance in maize. In addition, we found that HSF21 confers maize cold tolerance without incurring yield penalties. Collectively, this study establishes HSF21 as a key regulator that enhances cold tolerance in maize, providing valuable genetic resources for breeding of cold-tolerant maize varieties.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Variación Genética , Factores de Transcripción del Choque Térmico , Proteínas de Plantas , Zea mays , Zea mays/genética , Zea mays/metabolismo , Zea mays/fisiología , Factores de Transcripción del Choque Térmico/genética , Factores de Transcripción del Choque Térmico/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estudio de Asociación del Genoma Completo , Respuesta al Choque por Frío/genética , Frío , Factores de Transcripción/metabolismo , Factores de Transcripción/genética
7.
ACS Appl Mater Interfaces ; 16(31): 41596-41615, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39066695

RESUMEN

MXene emerges as a premier candidate for electromagnetic shielding owing to its unique properties as a novel two-dimensional material. Its exceptional electrical conductivity, chemical reactivity, surface tunability, and facile processing render it highly suitable for diverse electromagnetic shielding applications. The research status of MXene and MXene-based electromagnetic shielding materials is systematically discussed in this paper. First, the research status of MXene as a single-component electromagnetic shielding material is briefly introduced. Subsequently, the research status of composite structures constructed by MXene with polymers, carbon derivatives, and ferrites is introduced in detail. Furthermore, the research progress of MXene-based ternary and quaternary composite electromagnetic shielding materials is further focused. Finally, the application of MXene-based composite electromagnetic shielding materials is prospected. A deeper understanding of MXene's electromagnetic shielding properties is facilitated by this paper, providing the direction for the future development of two-dimensional materials in the design and processing of electromagnetic shielding materials.

8.
Science ; 385(6707): 433-438, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39052792

RESUMEN

The ever-increasing power conversion efficiency of perovskite solar cells has illuminated the future of the photovoltaic industry, but the development of commercial devices is hampered by their poor stability. In this study, we report a scalable stabilization method using vapor-phase fluoride treatment, which achieves 18.1%-efficient solar modules (228 square centimeters) with accelerated aging-projected T80 lifetimes (time to 80% of efficiency remaining) of 43,000 ± 9000 hours under 1-sun illumination at 30°C. The high stability results from vapor-enabled homogeneous fluorine passivation over large-area perovskite surfaces, suppressing defect formation energy and ion diffusion. The extracted degradation activation energy of 0.61 electron volts for solar modules is comparable to that of most reported stable cells, which indicates that modules are not inherently less stable than cells and closes the cell-to-module stability gap.

9.
Pflugers Arch ; 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39017932

RESUMEN

Neuropathic pain (NPP) is a refractory pain syndrome, caused by damage or disease of the somatosensory nervous system and characterized by spontaneous pain, hyperalgesia, abnormal pain and sensory abnormality. Non-coding RNAs (ncRNAs), including microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA (circRNA) and Piwi interacting RNA (piRNA), play a notable role in initiation and maintenance of NPP. In this review, we summarize the role of ncRNAs in NPP and their underlaying mechanism. Generally, ncRNAs are interacted with mRNA, protein or DNA to regulate the molecules and signals assciated with neuroinflammation, ion channels, neurotrophic factors and others, and then involved in the occurrence and development of NPP. Therefore, this review not only contributes to deepen our understanding of the pathophysiological mechanism of NPP, but also provides theoretical basis for the development of new therapy strategies for this disorder.

10.
Genes (Basel) ; 15(7)2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-39062629

RESUMEN

The epidermal cells of insects are polarized epithelial cells that play a pivotal role in the insect's molting process. Sinuous, a pivotal structural protein involved in the formation of septate junctions among epithelial cells, is essential for its physiological function. In this study, to determine whether sinuous participates in the regulation of insect molting, we identified the sinuous gene, Lmsinu, in Locusta migratoria, which encodes a protein belonging to the claudin family and shares 62.6% identity with Drosophila's sinuous protein. Lmsinu is expressed in multiple tissues, and its expression level in the integument significantly increases prior to molting. Knockdown of Lmsinu in L. migratoria results in larval mortality during molting. Furthermore, hematoxylin and eosin and chitin staining demonstrate that the downregulation of Lmsinu led to a prolonged degradation process of the old cuticle during the molting process. Electron microscopy analysis further revealed that knockdown of Lmsinu disrupts the formation of septate junctions among epidermal cells, which are a monolayer of polarized epithelial cells, which may hinder the functionality of epidermal cells during the process of molting. In summary, these findings suggest that Lmsinu plays a role in nymph molting by regulating the formation of septate junctions among epidermal cells.


Asunto(s)
Claudinas , Proteínas de Insectos , Locusta migratoria , Muda , Animales , Muda/genética , Locusta migratoria/genética , Locusta migratoria/metabolismo , Locusta migratoria/crecimiento & desarrollo , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Claudinas/genética , Claudinas/metabolismo , Larva/genética , Larva/crecimiento & desarrollo , Larva/metabolismo , Regulación del Desarrollo de la Expresión Génica
11.
Materials (Basel) ; 17(14)2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-39063679

RESUMEN

The size of the representative volume element (RVE) for the two-dimensional (2D) random aggregate numerical model of asphalt mortar in a non-destructive state, which directly affects the time required to simulate the linear viscoelastic behavior from asphalt mastic to asphalt mortar. However, in the existing literature, limited research has been conducted on the size determination of the numerical model RVE for asphalt mortar. To provide a recommended size for the typical 2D random aggregate numerical model RVE of asphalt mortar in a nondestructive state, this paper first applies the virtual specimen manufacturing method of asphalt concrete 2D random aggregate to asphalt mortar. Then, it generates numerical model RVEs of asphalt mortar with different maximum particle sizes, after which geometric and numerical analyses are conducted on these models. Finally, based on the geometric and numerical analysis results, the recommended minimum sizes of RVE for the 2D asphalt mortar numerical model are provided.

12.
Cell Signal ; 121: 111301, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39019338

RESUMEN

Ischemic stroke is one of the most disabling and fatal diseases around the world. The damaged brain tissues will undergo excessive autophagy, vascular endothelial cells injury, blood-brain barrier (BBB) impairment and neuroinflammation after ischemic stroke. However, there is no unified viewpoint on the underlying mechanism of brain damage. Transforming growth factor-ß1 (TGF-ß1), as a multi-functional cytokine, plays a crucial role in the intricate pathological processes and helps maintain the physiological homeostasis of brain tissues through various signaling pathways after ischemic stroke. In this review, we summarize the protective role of TGF-ß1 in autophagic flux, BBB, vascular remodeling, neuroinflammation and other aspects after ischemic stroke. Based on the review, we believe that TGF-ß1 could serve as a key target for treating ischemic stroke.


Asunto(s)
Autofagia , Barrera Hematoencefálica , Accidente Cerebrovascular Isquémico , Factor de Crecimiento Transformador beta1 , Humanos , Factor de Crecimiento Transformador beta1/metabolismo , Accidente Cerebrovascular Isquémico/metabolismo , Accidente Cerebrovascular Isquémico/patología , Animales , Barrera Hematoencefálica/metabolismo , Transducción de Señal , Células Endoteliales/metabolismo , Isquemia Encefálica/metabolismo
13.
Sci Total Environ ; 941: 173680, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38844212

RESUMEN

Microorganisms play a critical role in the biogeochemical cycling of selenium in natural ecosystems, particularly in reducing selenite (Se(IV)) to element selenium (Se(0)) which reduces its mobility and bioavailability. However, Se(IV)-reducing bacteria and their reducing characteristics in estuarine sediments remain inadequately understood. In this study, the reduction of Se(IV) was confirmed to be microbially driven through the cultivation of a mixture of estuarine sediment and Se(IV) under aerobic conditions. Community analysis indicates that Bacillus was primarily involved in the reduction of Se(IV). A strain with high salt tolerance (7.5 % NaCl) and Se(IV) resistance (up to 200 mM), Bacillus cereus SD1, was isolated from an estuarine sediment. The reduction of Se(IV) occurred concomitantly with the onset of microbial growth, and reduction capacity increased approximately 5-fold by adjusting the pH. In addition, Se(IV) reduction in Bacillus cereus SD1 was significantly inhibited by sulfite, and the key enzyme activity tests revealed the possible presence of a sulfite reductase-mediated Se(IV) reduction pathway. These research findings provide new insights into the bioreducing characteristics and the biogeochemical cycling of selenium in estuarine environments.


Asunto(s)
Estuarios , Sedimentos Geológicos , Selenio , Sedimentos Geológicos/microbiología , Sedimentos Geológicos/química , Selenio/metabolismo , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/metabolismo , Bacillus cereus/metabolismo , Oxidación-Reducción , Bacterias/metabolismo
15.
Comput Biol Med ; 174: 108489, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38640633

RESUMEN

Deep neural networks (DNNs) involve advanced image processing but depend on large quantities of high-quality labeled data. The presence of noisy data significantly degrades the DNN model performance. In the medical field, where model accuracy is crucial and labels for pathological images are scarce and expensive to obtain, the need to handle noisy data is even more urgent. Deep networks exhibit a memorization effect, they tend to prioritize remembering clean labels initially. Therefore, early stopping is highly effective in managing learning with noisy labels. Previous research has often concentrated on developing robust loss functions or implementing training constraints to mitigate the impact of noisy labels; however, such approaches have frequently resulted in underfitting. We propose using knowledge distillation to slow the learning process of the target network rather than preventing late-stage training from being affected by noisy labels. In this paper, we introduce a data sample self-selection strategy based on early stopping to filter out most of the noisy data. Additionally, we employ the distillation training method with dual teacher networks to ensure the steady learning of the student network. The experimental results show that our method outperforms current state-of-the-art methods for handling noisy labels on both synthetic and real-world noisy datasets. In particular, on the real-world pathological image dataset Chaoyang, the highest classification accuracy increased by 2.39 %. Our method leverages the model's predictions based on training history to select cleaner datasets and retrains them using these cleaner datasets, significantly mitigating the impact of noisy labels on model performance.


Asunto(s)
Redes Neurales de la Computación , Humanos , Aprendizaje Profundo , Procesamiento de Imagen Asistido por Computador/métodos , Algoritmos
16.
Angew Chem Int Ed Engl ; 63(28): e202404329, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38683742

RESUMEN

A hitherto unknown class of C4-symmetric Caryl-Cß (C3, C8, C13, C18) axially chiral porphyrins has been synthesized and the application of their iridium (Ir) complexes in catalytic asymmetric C(sp3)-H functionalization is documented. Cyclotetramerization of enantioenriched axially chiral 2-hydroxymethyl-3-naphthyl pyrroles under mild acidic conditions affords, after oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), the C4-symmetric α,α,α,α-atropenantiomer as an only isolable diastereomer. Both regioisomeric Ir(Por*)(CO)(Cl) complexes catalyze the carbene C-H insertion reaction affording the same enantiomer, albeit with slight difference in enantioselectivity. With the optimum Ir-complex 3 e, the 2-substituted arylacetic acid derivatives were generated from diazo compounds and cyclohexadiene in excellent yields and enantioselectivities.

17.
Insects ; 15(4)2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38667367

RESUMEN

Fushi-tarazu factor 1 (FTZ-F1) is a class of transcription factors belonging to the nuclear receptor superfamily and an important molting regulator in insects; however, its detailed function in the molting process of Locusta migratoria is still unclear. This study identified two FTZ-F1 transcripts (LmFTZ-F1-X1 and LmFTZ-F1-X2) in L. migratoria. The classical domains of FTZ-F1 were present in their protein sequences and distinguished based on their variable N-terminal domains. Reverse-transcription quantitative polymerase chain reaction analysis revealed that LmFTZ-F1-X1 and LmFTZ-F1-X2 were highly expressed in the integument. RNA interference (RNAi) was used to explore the function of LmFTZ-F1s in the molting of the third-instar nymph. Separate LmFTZ-F1-X1 or LmFTZ-F1-X2 silencing did not affect the normal development of third-instar nymphs; however, the simultaneous RNAi of LmFTZ-F1-X1 and LmFTZ-F1-X2 caused the nymphs to be trapped in the third instar stage and finally die. Furthermore, the hematoxylin-eosin and chitin staining of the cuticle showed that the new cuticles were thickened after silencing the LmFTZ-F1s compared to the controls. RNA-seq analysis showed that genes encoding four cuticle proteins, two chitin synthesis enzymes, and cytochrome P450 303a1 were differentially expressed between dsGFP- and dsLmFTZ-F1s-injected groups. Taken together, LmFTZ-F1-X1 and LmFTZ-F1-X2 are involved in the ecdysis of locusts, possibly by regulating the expression of genes involved in cuticle formation, chitin synthesis, and other key molting processes.

18.
Molecules ; 29(5)2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38474531

RESUMEN

A enantioselective tandem transformation, concerning asymmetric allylic decarboxylative addition and cyclization of N-nosylimines with vinylethylene carbonates (VECs), in the presence of [Rh(C2H4)2Cl]2, chiral sulfoxide-N-olefin tridentate ligand has been developed. The reaction of VECs with various substituted N-nosylimines proceeded smoothly under mild conditions, providing highly functionalized oxazolidine frameworks in good to high yields with good to excellent enantioselectivity.

19.
Bioresour Technol ; 399: 130563, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38461871

RESUMEN

An ultralight 3D carbon fiber aerogel with good flexibility is developed via soaking cotton in water and then calcinating at a high temperature. This cotton-derived carbon material is constituted by amorphous carbon and retains slight oxygen-containing groups. Besides, a lot of hollow carbon nanocapsules are yielded on the inside surface, resulting in abundant micropores and mesopores. Systemic investigations explore the molecular transformation from cotton to carbon fiber, and the formation of carbon nanocapsules. In the adsorption process for methyl orange (MO), this carbon fiber aerogel exhibits both a rapid adsorption rate and the ultrahigh adsorbability of 862.9 mg/g, outclassing most of carbon materials reported. Therefore, a dynamic sewage treatment system is built and consecutively removes hydrosoluble pollution for a long-term running time. For the cotton-derived carbon fiber aerogel, the good mechanical flexibility, excellent adsorption property, and high stability jointly provide a vast application prospect in future industrial wastewater remediation.


Asunto(s)
Nanocápsulas , Contaminantes Químicos del Agua , Fibra de Carbono , Carbono , Aguas del Alcantarillado , Adsorción , Gossypium
20.
Org Lett ; 26(9): 1970-1974, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38421216

RESUMEN

A well-defined tridentate chiral sulfoxide-N-olefin ligand has been designed and applied in rhodium-catalyzed asymmetric allylic substitutions of racemic allylic carbonates, providing the branched allylic products in good yields with good to high enantioselectivities and excellent regioselectivities. This reaction mechanism, which involves the possible hemilability of olefin coordination on sulfoxide-N-olefin hybrid ligands with rhodium, is elaborated as well.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA