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Non-invasive brain stimulations have drawn attention in remediating memory decline in older adults. However, it remains unclear regarding the cognitive and neural mechanisms underpinning the neurostimulation effects on memory rehabilitation. We evaluated the intervention effects of 2-weeks of neurostimulations (high-definition transcranial direct current stimulation, HD-tDCS, and electroacupuncture, EA versus controls, CN) on brain activities and functional connectivity during a working memory task in normally cognitive older adults (age 60+, n = 60). Results showed that HD-tDCS and EA significantly improved the cognitive performance, potentiated the brain activities of overlapping neural substrates (i.e. hippocampus, dlPFC, and lingual gyrus) associated with explicit and implicit memory, and modulated the nodal topological properties and brain modular interactions manifesting as increased intramodular connection of the limbic-system dominated network, decreased intramodular connection of default-mode-like network, as well as stronger intermodular connection between frontal-dominated network and limbic-system-dominated network. Predictive model further identified the neuro-behavioral association between modular connections and working memory. This preliminary study provides evidence that noninvasive neurostimulations can improve older adults' working memory through potentiating the brain activity of working memory-related areas and mediating the modular interactions of related brain networks. These findings have important implication for remediating older adults' working memory and cognitive declines.
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Memória de Curto Prazo , Estimulação Transcraniana por Corrente Contínua , Vida Independente , Encéfalo/diagnóstico por imagem , Sistema LímbicoRESUMO
Recent neurocognitive models propose that the insula serves as a hub of interoceptive awareness system, modulating 2 interplaying neurocognitive systems: The posterior insula (PI) receives and integrates various interoceptive signals; these signals are then transmitted to the anterior insula for processing higher-order representations into awareness, where the dorsal anterior insula (dAI) modulates the prefrontal self-control system and the ventral anterior insula (vAI) modulates the amygdala (AMG)-striatal reward-seeking circuit. We sought to test this view using a multimodal approach. We first used a resting-state functional magnetic resonance imaging (fMRI) approach with a sample of 120 undergraduate students. Then, we unpacked the neuro-cognitive association between insular connectivity and cognitive performance during an Iowa gambling fMRI task. Lastly, an independent Open Southwest University Longitudinal Imaging Multimodal dataset was used to validate the results. Findings suggested that the dAI was predominantly connected to the prefrontal regions; the vAI was primarily connected to the AMG-ventral-striatum system; and the PI was mainly connected to the visceral-sensorimotor system. Moreover, cognitive scores were positively correlated with FC between dAI and the self-control process of ventrolateral prefrontal cortex and were negatively correlated with FC between vAI and the reward-seeking process of orbitofrontal cortex and subgenual anterior cingulate cortex. The findings highlight the roles of our theorized subinsular functionality in the overall operation of the neural cognitive systems.
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Córtex Cerebral , Substância Branca , Humanos , Giro do Cíngulo , Imageamento por Ressonância Magnética , Córtex Insular , Mapeamento Encefálico/métodosRESUMO
The nondemented old-old over the age of 80 comprise a rapidly increasing population group; they can be regarded as exemplars of successful aging. However, our current understanding of successful aging in advanced age and its neural underpinnings is limited. In this study, we measured the microstructural and network-based topological properties of brain white matter using diffusion-weighted imaging scans of 419 community-dwelling nondemented older participants. The participants were further divided into 230 young-old (between 72 and 79, mean = 76.25 ± 2.00) and 219 old-old (between 80 and 92, mean = 83.98 ± 2.97). Results showed that white matter connectivity in microstructure and brain networks significantly declined with increased age and that the declined rates were faster in the old-old compared with young-old. Mediation models indicated that cognitive decline was in part through the age effect on the white matter connectivity in the old-old but not in the young-old. Machine learning predictive models further supported the crucial role of declines in white matter connectivity as a neural substrate of cognitive aging in the nondemented older population. Our findings shed new light on white matter connectivity in the nondemented aging brains and may contribute to uncovering the neural substrates of successful brain aging.
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Substância Branca , Humanos , Substância Branca/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Envelhecimento/psicologia , Imagem de Difusão por Ressonância Magnética , Mapeamento EncefálicoRESUMO
In recent years, electronic cigarettes (e-cigs) have gained popularity as stylish, safe, and effective smoking cessation aids, leading to widespread consumer acceptance. Although previous research has explored the acute effects of combustible cigarettes or nicotine replacement therapy on brain functional activities, studies on e-cigs have been limited. Using fNIRS, we conducted graph theory analysis on the resting-state functional connectivity of 61 male abstinent smokers both before and after vaping e-cigs. And we performed Pearson correlation analysis to investigate the relationship between alterations in network metrics and changes in craving. E-cig use resulted in increased degree centrality, nodal efficiency, and local efficiency within the executive control network (ECN), while causing a decrease in these properties within the default model network (DMN). These alterations were found to be correlated with reductions in craving, indicating a relationship between differing network topologies in the ECN and DMN and decreased craving. These findings suggest that the impact of e-cig usage on network topologies observed in male smokers resembles the effects observed with traditional cigarettes and other forms of nicotine delivery, providing valuable insights into their addictive potential and effectiveness as aids for smoking cessation.
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Fissura , Sistemas Eletrônicos de Liberação de Nicotina , Função Executiva , Espectroscopia de Luz Próxima ao Infravermelho , Vaping , Humanos , Masculino , Adulto , Função Executiva/efeitos dos fármacos , Função Executiva/fisiologia , Adulto Jovem , Rede de Modo Padrão/fisiopatologia , Rede de Modo Padrão/diagnóstico por imagem , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Abandono do Hábito de Fumar , Rede Nervosa/fisiopatologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacosRESUMO
A pulse laser with a wavelength of 1064 nm and a pulse width of 1 µs was used to experiment on the coating of a 2024 aluminum alloy surface. The removal performance of the pulse laser cleaning coating was explored by a single factor analysis and orthogonally conditions, and the effects of the laser power, scanning speed, and pulse frequency on the quality of laser coating removal were summarized. The mechanisms of pulse laser cleaning the coating were studied. The results show that the three parameters of the laser power, scanning speed, and pulse frequency have different effects on the quality of laser coating removal. Among them, with the increase of the scanning speed and pulse frequency, the quality of laser cleaning first increases and then decreases, respectively. With the increase in laser power, the quality of laser cleaning increases. A good laser cleaning quality can be achieved at the laser power of 16.5 W, a scanning speed of 600 mm/s, and a pulse frequency of 30 kHz. The laser cleaning coating involves a variety of mechanisms such as combustion, explosion, gasification, thermal vibration stripping, and laser plasma impact. The result can provide practical references for a better searching of the paint removal.
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Multifunctional protein APE1/APEX1/HAP1/Ref-1 (designated as APE1) plays important roles in nuclease-mediated DNA repair and redox regulation in transcription. However, it is unclear how APE1 regulates the DNA damage response (DDR) pathways. Here we show that siRNA-mediated APE1-knockdown or APE1 inhibitor treatment attenuates the ATR-Chk1 DDR under stress conditions in multiple immortalized cell lines. Congruently, APE1 overexpression (APE1-OE) activates the ATR DDR under unperturbed conditions, which is independent of APE1 nuclease and redox functions. Structural and functional analysis reveals a direct requirement of the extreme N-terminal motif within APE1 in the assembly of distinct biomolecular condensates in vitro and DNA/RNA-independent activation of the ATR DDR. Overexpressed APE1 co-localizes with nucleolar NPM1 and assembles biomolecular condensates in nucleoli in cancer but not non-malignant cells, which recruits ATR and activator molecules TopBP1 and ETAA1. APE1 protein can directly activate ATR to phosphorylate its substrate Chk1 in in vitro kinase assays. W119R mutant of APE1 is deficient in nucleolar condensation, and is incapable of activating nucleolar ATR DDR in cells and ATR kinase in vitro. APE1-OE-induced nucleolar ATR DDR activation leads to compromised ribosomal RNA transcription and reduced cell viability. Taken together, we propose distinct mechanisms by which APE1 regulates ATR DDR pathways.
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Proteínas de Ligação a DNA , Proteínas Nucleares , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Condensados Biomoleculares , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , DNA , Dano ao DNA , Proteínas de Ligação a DNA/genética , Proteínas Nucleares/metabolismo , RNA Ribossômico/genética , RNA Interferente Pequeno/genéticaRESUMO
Cerebral small vessel disease (CSVD) is characterized by widespread functional changes in the brain, as evident from abnormal brain activations during cognitive tasks. However, the existing findings in this area are not yet conclusive. We systematically reviewed 25 studies reporting task-related fMRI in five cognitive domains in CSVD, namely executive function, working memory, processing speed, motor, and affective processing. The findings highlighted: (1) CSVD affects cognitive processes in a domain-specific manner; (2) Compensatory and regulatory effects were observed simultaneously in CSVD, which may reflect the interplay between the negative impact of brain lesion and the positive impact of cognitive reserve. Combined with behavioral and functional findings in CSVD, we proposed an integrated model to illustrate the relationship between altered activations and behavioral performance in different stages of CSVD: functional brain changes may precede and be more sensitive than behavioral impairments in the early pre-symptomatic stage; Meanwhile, compensatory and regulatory mechanisms often occur in the early stages of the disease, while dysfunction/decompensation and dysregulation often occur in the late stages. Overall, abnormal hyper-/hypo-activations are crucial for understanding the mechanisms of small vessel lesion-induced behavioral dysfunction, identifying potential neuromarker and developing interventions to mitigate the impact of CSVD on cognitive function.
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Doenças de Pequenos Vasos Cerebrais , Disfunção Cognitiva , Humanos , Imageamento por Ressonância Magnética , Encéfalo/patologia , Cognição , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Doenças de Pequenos Vasos Cerebrais/patologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologiaRESUMO
Well-orchestrated maternal-fetal cross talk occurs via secreted ligands, interacting receptors, and coupled intracellular pathways between the conceptus and endometrium and is essential for successful embryo implantation. However, previous studies mostly focus on either the conceptus or the endometrium in isolation. The lack of integrated analysis impedes our understanding of early maternal-fetal cross talk. Herein, focusing on ligand-receptor complexes and coupled pathways at the maternal-fetal interface in sheep, we provide the first comprehensive proteomic map of ligand-receptor pathway cascades essential for embryo implantation. We demonstrate that these cascades are associated with cell adhesion and invasion, redox homeostasis, and the immune response. Candidate interactions and their physiological roles were further validated by functional experiments. We reveal the physical interaction of albumin and claudin 4 and their roles in facilitating embryo attachment to endometrium. We also demonstrate a novel function of enhanced conceptus glycolysis in remodeling uterine receptivity by inducing endometrial histone lactylation, a newly identified histone modification. Results from in vitro and in vivo models supported the essential role of lactate in inducing endometrial H3K18 lactylation and in regulating redox homeostasis and apoptotic balance to ensure successful implantation. By reconstructing a map of potential ligand-receptor pathway cascades at the maternal-fetal interface, our study presents new concepts for understanding molecular and cellular mechanisms that fine-tune conceptus-endometrium cross talk during implantation. This provides more direct and accurate insights for developing potential clinical intervention strategies to improve pregnancy outcomes following both natural and assisted conception.
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Histonas , Útero , Animais , Implantação do Embrião/fisiologia , Endométrio/metabolismo , Feminino , Histonas/metabolismo , Ligantes , Gravidez , Proteômica , Ovinos , Útero/metabolismoRESUMO
Proactive inhibition is a critical ability for smokers who seek to moderate or quit smoking. It allows them to pre-emptively refrain from seeking and using nicotine products, especially when facing salient smoking cues in daily life. Nevertheless, there is limited knowledge on the impact of salient cues on behavioural and neural aspects of proactive inhibition, especially in smokers with nicotine withdrawal. Here, we seek to bridge this gap. To this end, we recruited 26 smokers to complete a stop-signal anticipant task (SSAT) in two separate sessions: once in the neutral cue condition and once in the smoking cue condition. We used graph-based modularity analysis to identify the modular structures of proactive inhibition-related network during the SSAT and further investigated how the interactions within and between these modules could be modulated by different proactive inhibition demands and salient smoking cues. Findings pointed to three stable brain modules involved in the dynamical processes of proactive inhibition: the sensorimotor network (SMN), cognitive control network (CCN) and default-mode network (DMN). With the increase in demands, functional connectivity increased within the SMN, CCN and between SMN-CCN and decreased within the DMN and between SMN-DMN and CCN-DMN. Salient smoking cues disturbed the effective dynamic interactions of brain modules. The profiles for those functional interactions successfully predicted the behavioural performance of proactive inhibition in abstinent smokers. These findings advance our understanding of the neural mechanisms of proactive inhibition from a large-scale network perspective. They can shed light on developing specific interventions for abstinent smokers.
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Sinais (Psicologia) , Nicotina , Humanos , Fumantes , Inibição Proativa , Imageamento por Ressonância Magnética , Encéfalo , Fumar/psicologia , Mapeamento EncefálicoRESUMO
White matter abnormalities represent early neuropathological events in neurodegenerative diseases such as Alzheimer's disease (AD), investigating these white matter alterations would likely provide valuable insights into pathological changes over the course of AD. Using a novel mathematical framework called "Director Field Analysis" (DFA), we investigated the geometric microstructural properties (i.e., splay, bend, twist, and total distortion) in the orientation of white matter fibers in AD, amnestic mild cognitive impairment (aMCI), and cognitively normal (CN) individuals from the Alzheimer's Disease Neuroimaging Initiative 2 database. Results revealed that AD patients had extensive orientational changes in the bilateral anterior thalamic radiation, corticospinal tract, inferior and superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus in comparison with CN. We postulate that these orientational changes of white matter fibers may be partially caused by the expansion of lateral ventricle, white matter atrophy, and gray matter atrophy in AD. In contrast, aMCI individuals showed subtle orientational changes in the left inferior longitudinal fasciculus and right uncinate fasciculus, which showed a significant association with the cognitive performance, suggesting that these regions may be preferential vulnerable to breakdown by neurodegenerative brain disorders, thereby resulting in the patients' cognitive impairment. To our knowledge, this article is the first to examine geometric microstructural changes in the orientation of white matter fibers in AD and aMCI. Our findings demonstrate that the orientational information of white matter fibers could provide novel insight into the underlying biological and pathological changes in AD and aMCI.
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Doença de Alzheimer/patologia , Amnésia/patologia , Disfunção Cognitiva/patologia , Imagem de Tensor de Difusão , Substância Branca/patologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Amnésia/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Feminino , Humanos , Masculino , Fibras Nervosas Mielinizadas/patologia , Substância Branca/diagnóstico por imagemRESUMO
This study aimed to identify significant biomarkers related to the prognosis of liver cancer using long noncoding RNA (lncRNA)-associated competing endogenous RNAs (ceRNAs) analysis. Differentially expressed mRNA and lncRNAs between liver cancer and paracancerous tissues were screened, and the functions of these mRNAs were predicted by gene ontology and pathway enrichment analyses. A ceRNA network consisting of differentially expressed mRNAs and lncRNAs was constructed. LncRNA FENDRR and lncRNA HAND2-AS1 were hub nodes in the ceRNA network. A risk score assessment model consisting of eight genes (PDE2A, ESR1, FBLN5, ALDH8A1, AKR1D1, EHHADH, ADRA1A, and GNE) associated with prognosis were developed. Multivariate Cox regression suggested that both pathologic_T and risk group could be regarded as independent prognostic factors. Furthermore, a nomogram model consisting of pathologic_T and risk group showed a good prediction ability for predicting the survival rate of liver cancer patients. The nomogram model consisting of pathologic_T and a risk score assessment model could be regarded as an independent factor for predicting prognosis of liver cancer.
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Biomarcadores Tumorais/genética , Detecção Precoce de Câncer , Neoplasias Hepáticas/genética , RNA Longo não Codificante/genética , Idoso , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Redes Reguladoras de Genes/genética , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/patologia , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Prognóstico , RNA Mensageiro/genéticaRESUMO
Sirt1 is a member of the sirtuin family of proteins and has important roles in numerous biological processes. Sirt1-/- mice display an increased frequency of abnormal spermatozoa, but the mechanism of Sirt1 in spermiogenesis remains largely unknown. Here, we report that Sirt1 might be directly involved in spermiogenesis in germ cells but not in steroidogenic cells. Germ cell-specific Sirt1 knockout mice were almost completely infertile; the early mitotic and meiotic progression of germ cells in spermatogenesis were not obviously affected after Sirt1 depletion, but subsequent spermiogenesis was disrupted by a defect in acrosome biogenesis, which resulted in a phenotype similar to that observed in human globozoospermia. In addition, LC3 and Atg7 deacetylation was disrupted in spermatids after knocking out Sirt1, which affected the redistribution of LC3 from the nucleus to the cytoplasm and the activation of autophagy. Furthermore, Sirt1 depletion resulted in the failure of LC3 to be recruited to Golgi apparatus-derived vesicles and in the failure of GOPC and PICK1 to be recruited to nucleus-associated acrosomal vesicles. Taken together, these findings reveal that Sirt1 has a novel physiological function in acrosome biogenesis.
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Acrossomo/fisiologia , Sirtuína 1/fisiologia , Espermatogênese/fisiologia , Acrossomo/patologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Autofagia/genética , Autofagia/fisiologia , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular , Modelos Animais de Doenças , Proteínas da Matriz do Complexo de Golgi , Humanos , Infertilidade Masculina/etiologia , Infertilidade Masculina/genética , Infertilidade Masculina/patologia , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Microscopia Eletrônica de Transmissão , Modelos Biológicos , Proteínas Nucleares/metabolismo , Fenótipo , Sirtuína 1/deficiência , Sirtuína 1/genética , Espermatogênese/genética , Espermatozoides/patologia , Espermatozoides/fisiologia , Esteroides/biossíntese , Teratozoospermia/etiologia , Teratozoospermia/patologiaRESUMO
Glucocorticoids (GCs) are an important anti-inflammatory drug, used widely, regardless of its side effects. GCs can affect intestinal flora directly or indirectly, though few studies have focused on the changes of gut microbiota composition. In this study, ICR mice were randomly divided into three groups, gavage administration with saline, and different doses of dexamethasone (DEX): 0.1 mg/kg and 1 mg/kg. Five days later, the microbial diversity of the colon contents was analyzed. A significant loss in weight was observed in the DEX1.0 group as compared with the control group (P = 0.011). The gut microbiota richness (ACE, P = 0.01; Chao, P = 0.013) and diversity (Shannon, P = 0.035; Simpson, P = 0.032) were decreased in DEX group. The proportions of genus Butyricicoccus, Oscillibacter, Anaerotruncus, Ruminiclostridium, Ruminococcaceae, and Lachnospiraceae were the most abundant and predominant followed by Lactobacillus, Pseudomonas, and Enterorhabdus. Dex administration led to changes in the liver/body ratio and spleen/body ratio. The results obtained from our study indicate that DEX can decrease the level of WBC and change the structure of the gut microbiota composition; moreover, the results of this study provide new insight into alleviating the clinical side effects of GC therapy.
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Anti-Inflamatórios/farmacologia , Bactérias/efeitos dos fármacos , Dexametasona/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Glucocorticoides/farmacologia , Animais , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Peso Corporal/efeitos dos fármacos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos ICRRESUMO
Aging involves cognitive decline and prominent alterations in brain activity. Electroacupuncture (EA), a traditional Chinese medicine approach, is demonstrated to be effective in improving cognitive function of older adults. However, the specific neural mechanism underlying this modulation effect remains unclear. In this study, we used functional magnetic resonance imaging (fMRI) to investigate whether EA could improve cognitive performance of community-dwelling older adults and whether these potential improvements are associated with the EA-induced brain functional connectivity alterations. Thirty healthy older adults were recruited and randomly assigned to the EA group and the control group. Behaviorally, we observed an EA-induced improvement in cognitive performance of older adults in the Montreal Cognitive Assessment. On a neural perspective, the EA intervention significantly increased the functional connectivity within the default mode network. Moreover, we found a positive association between the improvement in delayed memory performance and the alterations in the ventral medial prefrontal cortex-hippocampal formation connectivity in the EA group. This study extends previous findings by showing that healthy older adults exhibit neural plasticity manifested as increased functional connectivity after EA sessions, which could induce therapeutic effects in the treatment of neurodegenerative diseases.
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Encéfalo/fisiopatologia , Eletroacupuntura/métodos , Idoso , Envelhecimento , Feminino , Voluntários Saudáveis , Humanos , MasculinoRESUMO
Carbon dots (Cdots) with bright green fluorescence were applied to the rapid and selective cell imaging for a variety of cell lines. Different labeling distributions of hepatoma cells (HepG2) and normal human liver cells (LO2) were achieved using Cdots as imaging agents. For HepG2 cells, the Cdots could rapidly permeate the cell membrane and diffuse into the cytoplasm and nucleus within 3 min, and retained their location in the targets for 24 h. However, the Cdots exhibited bright fluorescence only in the cytoplasm of LO2 cell lines. Moreover, the Cdots were almost non-cytotoxic and exhibited superior photostability over a wide range of pH. Therefore, these Cdots have great potential for rapid, luminous and selective bioimaging applications, and are expected to be used as a nucleus-staining agent in cancer diagnosis. Graphical abstract á .
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Carbono/química , Carcinoma Hepatocelular/diagnóstico por imagem , Corantes Fluorescentes/química , Neoplasias Hepáticas/diagnóstico por imagem , Nanopartículas/química , Imagem Óptica/métodos , Pontos Quânticos/química , Linhagem Celular , Células Hep G2 , Humanos , Modelos Moleculares , Imagem Óptica/economia , Pontos Quânticos/ultraestrutura , Fatores de TempoRESUMO
Materials with low ice adhesion and long-lasting anti-icing properties remain an ongoing challenge in ultralow temperature environments (≤-30 °C). This study presents a gel material consisting of a polymer matrix (copolymer of polyurethane and acrylamide) and an anti-icing agent, ethylene glycol (EG), designed for anti-icing applications at ultralow temperatures. The surface shows a prolonged droplet freezing delay of ca. 322 s at -30 °C and frost resistance properties. It also exhibits an ice adhesion strength of 1.1 kPa at -10 °C and 39.8 kPa at -50 °C, resulting from the interaction between EG and water molecules that hinders the crystallization of ice as well as the significant mismatch between elastic gel and ice. In addition, the gel surface exhibits favorable anti-icing durability, with an ice adhesion strength below 20.0 kPa after 25 icing/deicing cycles and mechanical scratch tests. The gel demonstrates remarkable thermal durability, achieved through the H-bonds between the EG and polymer matrix. The H-bonds further enhance the anti-icing performance, thereby remarkably decreasing EG depletion and improving anti-icing durability. Overall, these properties suggest the potential application of this gel material in harsh environments including polar regions.
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In response to DNA double-strand breaks or oxidative stress, ATM-dependent DNA damage response (DDR) is activated to maintain genome integrity. However, it remains elusive whether and how DNA single-strand breaks (SSBs) activate ATM. Here, we provide direct evidence in Xenopus egg extracts that ATM-mediated DDR is activated by a defined SSB structure. Our mechanistic studies reveal that APE1 promotes the SSB-induced ATM DDR through APE1 exonuclease activity and ATM recruitment to SSB sites. APE1 protein can form oligomers to activate the ATM DDR in Xenopus egg extracts in the absence of DNA and can directly stimulate ATM kinase activity in vitro. Our findings reveal distinct mechanisms of the ATM-dependent DDR activation by SSBs in eukaryotic systems and identify APE1 as a direct activator of ATM kinase.
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Proteínas Mutadas de Ataxia Telangiectasia , Quebras de DNA de Cadeia Simples , DNA Liase (Sítios Apurínicos ou Apirimidínicos) , Transdução de Sinais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Animais , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Proteínas de Xenopus/metabolismo , Proteínas de Xenopus/genética , Humanos , Xenopus laevis , Reparo do DNARESUMO
Pneumatic conveying devices are commonly used in the fields of chemical industry, raw material transportation, and material processing. Elongated biomass particles are not evenly distributed in the lifting tube because biomass clumps during conveying. Pneumatic conveying test setup and measurement system were built in this paper in order to study the agglomeration behavior of elongated biomass particles in the lifting tube experimentally. Particle tracking velocimetry (PTV) was used to determine the area distribution and velocity distribution of particles at different apparent air velocities and mass flow rates. The results show that while keeping the mass flow rate constant at 46.50 g/s, the apparent gas velocity increased from 5.91 to 7.91 m/s and the maximum size of agglomerates decreased from 0.689 to 0.235. The apparent gas velocity was kept at 6.40 m/s, and the particle mass flow rate was adjusted from 56.50 to 16.20 g/s. The maximum size of the agglomerates was reduced to 0.115. Therefore, appropriately increasing the apparent gas velocity or decreasing the particle mass flow rate can improve the uniformity of the particle distribution in the lifting tube. The results would provide a reference for parameter adjustment of pneumatic conveying devices in industrial production.
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Passive all-day radiative cooling (PARC) films with porous structures prepared via nonsolvent-induced phase separation (NIPS) have attracted considerable attention owing to their cost-effectiveness and wide applicability. The PARC performances of the films correlate with their porous structures. However, the porous structure formed using the NIPS process cannot be finely regulated. In this study, we prepared polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) films with porous structures optimized by rationally tuning the phase separation, which was achieved by adjusting the proportions of two good solvents with varying solubility parameters. The optimized PVDF-HFP film with a hierarchically porous structure exhibited a high solar reflectance of 97.7% and an infrared emissivity of 96.7%. The film with excellent durability achieved an average subambient cooling temperature of approximately 5.4 °C under a solar irradiance of 945 W·m-2 as well as a temperature of 11.2 °C at nighttime, thus demonstrating all-day radiative cooling. The results indicate that the proposed films present a promising platform for large-scale applications in green building cooling and achieving carbon neutrality.
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The excessively leached metal ions from traditional metallic antimicrobial nanoparticles are harmful to biological and human tissues. Metal-organic frameworks (MOFs) coordinating bioactive metal ions to organic bridging ligands can potentially address this issue, avoiding the excessive leaching of metal ions and simultaneously exhibiting high effective antibacterial activities. Here, we report the preparation of a 2-dimensional leaves-like zeolitic imidazolate framework (ZIF-L) for potential antibacterial and anti-algae applications. The ZIF-L nanosheet exhibits complete inactivation of Escherichia coli (phosphate buffer saline: 4 h) and Bacillus subtilis (seawater: 0.5 h). The ZIF-L/epoxy composite has excellent antibacterial effect, poisoning effect and anti-adhesion effect on a variety of marine algae. It is worth noting that the removal rate (Escherichia coli) for ZIF/epoxy composite can be reached to 90.20% by only adding ZIF-L (0.25 wt%). This work will inspire researchers to develop more metal-organic frameworks materials for applications in the antibacterial and anti-algae fields.