RESUMO
Mechanotransduction plays a crucial role in vascular biology. One example of this is the local regulation of vascular resistance via flow-mediated dilation (FMD). Impairment of this process is a hallmark of endothelial dysfunction and a precursor to a wide array of vascular diseases, such as hypertension and atherosclerosis. Yet the molecules responsible for sensing flow (shear stress) within endothelial cells remain largely unknown. We designed a 384-well screening system that applies shear stress on cultured cells. We identified a mechanosensitive cell line that exhibits shear stress-activated calcium transients, screened a focused RNAi library, and identified GPR68 as necessary and sufficient for shear stress responses. GPR68 is expressed in endothelial cells of small-diameter (resistance) arteries. Importantly, Gpr68-deficient mice display markedly impaired acute FMD and chronic flow-mediated outward remodeling in mesenteric arterioles. Therefore, GPR68 is an essential flow sensor in arteriolar endothelium and is a critical signaling component in cardiovascular pathophysiology.
Assuntos
Mecanotransdução Celular , Interferência de RNA , Receptores Acoplados a Proteínas G/fisiologia , Animais , Materiais Biocompatíveis , Cálcio/metabolismo , Linhagem Celular Tumoral , Células Endoteliais/fisiologia , Endotélio Vascular/citologia , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Concentração de Íons de Hidrogênio , Artérias Mesentéricas/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/metabolismo , RNA Interferente Pequeno/metabolismo , Receptores Acoplados a Proteínas G/genética , Resistência ao Cisalhamento , Estresse Mecânico , Resistência VascularRESUMO
The recent discovery of superconductivity in La3Ni2O7-δ under high pressure with a transition temperature around 80 K (ref. 1) has sparked extensive experimental2-6 and theoretical efforts7-12. Several key questions regarding the pairing mechanism remain to be answered, such as the most relevant atomic orbitals and the role of atomic deficiencies. Here we develop a new, energy-filtered, multislice electron ptychography technique, assisted by electron energy-loss spectroscopy, to address these critical issues. Oxygen vacancies are directly visualized and are found to primarily occupy the inner apical sites, which have been proposed to be crucial to superconductivity13,14. We precisely determine the nanoscale stoichiometry and its correlation to the oxygen K-edge spectra, which reveals a significant inhomogeneity in the oxygen content and electronic structure within the sample. The spectroscopic results also reveal that stoichiometric La3Ni2O7 has strong charge-transfer characteristics, with holes that are self-doped from Ni sites into O sites. The ligand holes mainly reside on the inner apical O and the planar O, whereas the density on the outer apical O is negligible. As the concentration of O vacancies increases, ligand holes on both sites are simultaneously annihilated. These observations will assist in further development and understanding of superconducting nickelate materials. Our imaging technique for quantifying atomic deficiencies can also be widely applied in materials science and condensed-matter physics.
RESUMO
Although high-transition-temperature (high-Tc) superconductivity in cuprates has been known for more than three decades, the underlying mechanism remains unknown1-4. Cuprates are the only unconventional superconductors that exhibit bulk superconductivity with Tc above the liquid-nitrogen boiling temperature of 77 K. Here we observe that high-pressure resistance and mutual inductive magnetic susceptibility measurements showed signatures of superconductivity in single crystals of La3Ni2O7 with maximum Tc of 80 K at pressures between 14.0 GPa and 43.5 GPa. The superconducting phase under high pressure has an orthorhombic structure of Fmmm space group with the [Formula: see text] and [Formula: see text] orbitals of Ni cations strongly mixing with oxygen 2p orbitals. Our density functional theory calculations indicate that the superconductivity emerges coincidently with the metallization of the σ-bonding bands under the Fermi level, consisting of the [Formula: see text] orbitals with the apical oxygen ions connecting the Ni-O bilayers. Thus, our discoveries provide not only important clues for the high-Tc superconductivity in this Ruddlesden-Popper double-layered perovskite nickelates but also a previously unknown family of compounds to investigate the high-Tc superconductivity mechanism.
RESUMO
Climate change has been and will be accompanied by widespread changes in surface temperature. It is clear that these changes include global-wide increases in mean surface temperature and changes in temperature variance that are more regionally-dependent1-3. It is less clear whether they also include changes in the persistence of surface temperature. This is important as the effects of weather events on ecosystems and society depend critically on the length of the event. Here we provide an extensive survey of the response of surface temperature persistence to climate change over the twenty-first century from the output of 150 simulations run on four different Earth system models, and from simulations run on simplified models with varying representations of radiative processes and large-scale dynamics. Together, the results indicate that climate change simulations are marked by widespread changes in surface temperature persistence that are generally most robust over ocean areas and arise due to a seemingly broad range of physical processes. The findings point to both the robustness of widespread changes in persistence under climate change, and the critical need to better understand, simulate and constrain such changes.
Assuntos
Mudança Climática/estatística & dados numéricos , Modelos Climáticos , Temperatura , Aquecimento Global/prevenção & controle , Aquecimento Global/estatística & dados numéricos , Oceanos e Mares , Fatores de TempoRESUMO
Enhancer of Zeste Homolog 1 (EZH1) and Enhancer of Zeste Homolog 2 (EZH2) are the key components of polycomb repressive complex 2 (PRC2); however, the roles of these proteins in oral squamous cell carcinoma (OSCC) have yet to be elucidated. In this study, we aimed to determine the respective roles of these proteins in OSCC by investigating the expression levels of EZH1 and EZH2 in OSCC tissues (N = 63) by immunohistochemistry. In addition, we used lentiviruses to construct stable OSCC cell lines that overexpressed EZH1 and EZH2. Then, we investigated these cell lines for cell viability, colony formation capacity, stemness, and epithelial-mesenchymal transition (EMT). Binding competition between EZH1 and EZH2 with PRC2 was further evaluated using Co-immunoprecipitation (Co-IP). Compared with normal tissues, the expression levels of EZH2 in OSCC tissues was up-regulated, while the expression of EZH1 was down-regulated. EZH2 enhanced cell viability, colony formation capacity, stemness, and EMT, while EZH1 did not. Furthermore, analysis indicated that EZH1 and EZH2 bound competitively to PRC2 and influenced the methylation status of H3K27. In conclusion, our findings verified that EZH1 and EZH2 play opposing roles in OSCC and that EZH1 and EZH2 compete as the key component of PRC2, thus affecting the characteristics of OSCC via the methylation of H3K27.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço , Neoplasias Bucais/genética , Complexo Repressor Polycomb 2/genéticaRESUMO
Myocardial infarction (MI) is the primary source of death in cardiovascular diseases. Myricitrin (MYR) is a phenolic compound known for its antioxidant properties. This study aimed to investigate the impact of MYR alone or combined with exercise on a rat model of MI and its underlying mechanism. Sprague-Dawley rats were randomized into 5 groups: sham-operated (Sham), MI-sedentary (MI-Sed), MI-exercise (MI-Ex), MI-sedentary + MYR (MI-Sed-MYR) and MI-exercise + MYR (MI-Ex-MYR). MI was induced through ligation of left anterior descending coronary artery. The treatment with exercise or MYR (30 mg/kg/d) gavage began one week after surgery, either individually or in combination. After 8 weeks, the rats were assessed for cardiac function. Myocardial injuries were estimated using triphenyltetrazolium chloride, sirius red and Masson staining. Changes in reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), apoptosis and Nrf2/HO-1 pathway were analyzed by ROS kit, JC-1 kit, TUNEL assay, Western blot and immunohistochemistry. Both MYR and exercise treatments improved cardiac function, reduced infarct size, suppressed collagen deposition, and decreased myocardial fibrosis. Additionally, both MYR and exercise treatments lowered ROS production induced by MI, restored ΔΨm, and attenuated oxidative stress and apoptosis in cardiomyocytes. Importantly, the combination of MYR and exercise showed greater efficacy compared to individual treatments. Mechanistically, the combined intervention activated the Nrf2/HO-1 signaling pathway. These findings suggest that the synergistic effect of MYR and exercise may offer a promising therapeutic approach for alleviating MI.
RESUMO
Intrinsically disordered proteins (IDPs) participate in various biological processes. Interactions involving IDPs are usually dynamic and are affected by their inherent conformation fluctuations. Comprehensive characterization of these interactions based on current techniques is challenging. Here, we present GSALIDP, a GraphSAGE-embedded LSTM network, to capture the dynamic nature of IDP-involved interactions and predict their behaviors. This framework models multiple conformations of IDP as a dynamic graph, which can effectively describe the fluctuation of its flexible conformation. The dynamic interaction between IDPs is studied, and the data sets of IDP conformations and their interactions are obtained through atomistic molecular dynamic (MD) simulations. Residues of IDP are encoded through a series of features including their frustration. GSALIDP can effectively predict the interaction sites of IDP and the contact residue pairs between IDPs. Its performance in predicting IDP interactions is on par with or even better than the conventional models in predicting the interaction of structural proteins. To the best of our knowledge, this is the first model to extend the protein interaction prediction to IDP-involved interactions.
Assuntos
Proteínas Intrinsicamente Desordenadas , Simulação de Dinâmica Molecular , Conformação Proteica , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Ligação ProteicaRESUMO
The increasing number of vehicles are emitting a large amount of particles into the atmosphere, causing serious harm to the ecological environment and human health. This study conducted the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) to investigate the emission characteristics of particle number (PN) of China-VI gasoline vehicles with different gasoline. The gasoline with lower aromatic hydrocarbons and olefins reduced particulate matter (PM) and PN emissions by 24% and 52% respectively. The average PN emission rate of the four vehicles during the first 300 s (the cold start period) was 7.2 times that of the 300 s-1800s. Additionally, because the particle transmission time and instrument response time, the test results of instantaneous emissions of PN were not synchronized with vehicle specific power (VSP). By calculating the Spearman correlation coefficient between pre-average vehicle specific power (PAVSP) and the test results of PN instantaneous emissions, the delay time was determined as 10s. After the PN emissions results were corrected, the PN emissions were found to be more related to VSP. By analyzing the influence of driving status on emission, this study found that vehicles in acceleration mode increased PN emissions by 76% compared to those in constant speed mode.
Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Gasolina , Material Particulado , Emissões de Veículos , Emissões de Veículos/análise , Gasolina/análise , China , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Condução de Veículo , Poluição do Ar/estatística & dados numéricosRESUMO
INTRODUCTION: The treatment strategy for dual antiplatelet therapy (DAPT) with ticagrelor has been controversial in East Asian patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Our meta-analysis aimed to demonstrate whether intensified antithrombotic regimens with ticagrelor plus aspirin have more beneficial effects and fewer adverse events compared to those of clopidogrel plus aspirin in East Asian patients with ACS undergoing PCI. METHODS: We searched PubMed, Embase, Web of Science, ScienceDirect, Clinical Trials, Cochrane Library, and Chinese Clinical Trial Registry for randomized controlled trials (RCTs) comparing the efficacy of DAPT with ticagrelor or clopidogrel plus aspirin for secondary prevention of ACS in East Asian patients undergoing PCI. Risk ratios (RRs) and 95% confidence intervals (CIs) were used as the metrics of choice for assessing treatment effects. The primary endpoint was bleeding events, and the secondary endpoints were major adverse cardiovascular and cerebrovascular events (MACCEs, including cardiovascular death, nonfatal myocardial infarction [MI], and stroke), all-cause death, and definite/probable/possible stent thrombosis. The I2 index was used to assess heterogeneity. RESULTS: Six RCTs involving a total of 2,725 patients met the inclusion criteria. The incidence of all bleeding events with ticagrelor was higher than that with clopidogrel (RR, 1.65; 95% CI, 1.31-2.07), but the incidence of MACCE was not significantly different between the two groups (RR, 1.08; 95% CI, 0.54-2.16). All-cause death (RR, 1.10; 95% CI, 0.67-1.79), cardiovascular death (RR, 1.42; 95% CI, 0.68-2.98), nonfatal MI (RR, 0.92; 95% CI, 0.48-1.78), stroke (RR, 1.00; 95% CI, 0.40-2.50), and stent thrombosis (RR, 0.76; 95% CI, 0.19-2.98) were not statistically different between the two groups. CONCLUSION: Ticagrelor increased the risk of bleeding and did not increase treatment efficacy compared to that of clopidogrel in the East Asian population who have ACS treated with PCI.
Assuntos
Síndrome Coronariana Aguda , Aspirina , Clopidogrel , Intervenção Coronária Percutânea , Inibidores da Agregação Plaquetária , Ticagrelor , Humanos , Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/tratamento farmacológico , Síndrome Coronariana Aguda/terapia , Aspirina/efeitos adversos , Aspirina/uso terapêutico , Clopidogrel/efeitos adversos , Clopidogrel/uso terapêutico , População do Leste Asiático , Hemorragia/induzido quimicamente , Infarto do Miocárdio/etiologia , Intervenção Coronária Percutânea/efeitos adversos , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Acidente Vascular Cerebral/etiologia , Ticagrelor/efeitos adversos , Ticagrelor/uso terapêutico , Resultado do TratamentoRESUMO
OBJECTIVE: A hypercoagulable state exists in patients with oral squamous cell carcinoma (OSCC), but the role of platelets in the tumour microenvironment has not been explored. This study revealed the status of intratumoral plateletmicrothrombi (PLT-MT) and their clinicopathological relevance and predictive value in OSCC. STUDY DESIGN: This study retrospectively evaluated 106 OSCC patients. Tumour and tumour-adjacent tissue specimens were used to stain PLT-MT. Clinicopathological information, patient follow-ups and outcomes and preoperative coagulation and inflammatory hematologic indicators were collected, and their correlation with PLT-MT was analysed. RESULTS: Intratumoral PLT-MT was present in 35 of 106 patients with OSCC who had higher preoperative D-dimer, CRP, FIB and PT levels and lower TT levels. PLT-MT was an independent correlative factor of lymph node metastasis and suggested worse OS in N0 patients. CONCLUSIONS: Intratumoral PLT-MT was found in OSCC and was correlated with a hypercoagulable inflammatory state. PLT-MT was an independent marker of lymph node metastasis and showed potential in prognosis prediction.
RESUMO
Osteoarthritis (OA) is a common chronic joint degenerative disease and a major cause of disability in the elderly. However, the current intervention strategies cannot effectively improve OA, and the pathogenesis of OA remains elusive. The present study identified RNA binding motif protein 47 (RBM47) as an upstream modulator of key dysregulation gene co-expression module based on weighted gene co-expression network analysis (WGCNA) analysis and least absolute shrinkage and selection operator (Lasso) modeling. Subsequently, data from real-time quantitative PCR and western blot analysis revealed that RBM47 was upregulated in OA models in vivo and in vitro compared with normal controls. Functional analysis results from the MTT assay, flow cytometry, evaluation of LDH activities and inflammatory mediators, and western blot analysis of extracellular matrix (ECM) proteins, showed that RBM47 knockdown significantly alleviated inflammation, apoptosis, and ECM degradation in interleukin 1ß (IL-1ß)-treated chondrocytes. Mechanistically, RBM47 bound to F box only protein 2 (FBXO2) and stabilized FBXO2 messenger RNA (mRNA) to promote the phosphorylation of signal transducer and activator of transcription 3 (STAT3) in chondrocytes. Results from the recovery assay showed that the re-activation of STAT3 signaling by overexpressing FBXO2 or STAT3 counteracted the alleviating effect of RBM47 downregulation on IL-1ß-induced inflammation, apoptosis, and ECM degradation. Altogether, our findings illustrate that RBM47 stabilizes FBXO2 mRNA to advance OA development by activating STAT3 signaling, which enhances our understanding of the molecular regulatory mechanisms underlying the development of OA.
RESUMO
Here, using various substrates, we demonstrate that the in-plane uniaxial strain engineering can enhance the Jahn-Teller distortions and promote selective orbital occupancy to induce an emergent antiferromagnetic insulating (AFI) phase at x = 1/3 of La1-xCaxMnO3. Such an AFI phase depends not only on the magnitude of epitaxial strain but also on the symmetry of the substrates. Using the large uniaxial strain imparted by DyScO3(001) substrate, the AFI ground state is achieved in a wide range of doping levels (0 ≤ x ≤ 1/2), leaving an extended AFI phase diagram. Moreover, it is found that hydrostatic pressure can tune the AFI phase back to a hidden ferromagnetic metallic phase, accompanied by the formation of accommodation strain. The coaction of the accommodation strain, uniaxial strain, and hydrostatic pressure produces complex phase competition and evolution, and the result may shed light on phase space control of other functional perovskites with the competing magnetic interactions.
RESUMO
Due to the lack of engine reference torque and the accumulated work of reference transient cycle, the work based window (WBW) method for portable emission measurement system test data processing cannot be used for vehicle emission assessment in the current on-board diagnostics (OBD) system in China. In this work, a fuel-consumption based window (FBW) method was proposed to imitate a WBW method procedure by using fuel consumption rate as an alternative parameter to scale the window so the entire procedure can be based on the attainable data items in the OBD system. Some key issues regarding converting WBW method to FBW method, including window separation, window average power ratio calculation and specific NOx emission conversion from mg/kg. fuel to mg/kW.h, were solved by linking the 100-km fuel consumption and the average vehicle specific power of China World Transient Vehicle Cycle test. The comparison between the FBW and WBW methods on the NOx emission calculation results shows that the number of all windows, the number of valid windows, and the thresholds for >50% valid windows are quite similar for WBW and FBW methods. The estimation accuracy of average power ratio for the FBW method depends on the value of transmission efficiency of vehicle driveline. The deviations of 90% specific NOx emission in mg/kW.h between the two methods are smaller than 6% for the cases investigated in the present work.
RESUMO
The plant hormone auxin controls many aspects of plant development. Membrane trafficking processes, such as secretion, endocytosis and recycling, regulate the polar localization of auxin transporters in order to establish an auxin concentration gradient. Here, we investigate the function of the Arabidopsis thaliana R-SNAREs VESICLE-ASSOCIATED MEMBRANE PROTEIN 721 (VAMP721) and VAMP722 in the post-Golgi trafficking required for proper auxin distribution and seedling growth. We show that multiple growth phenotypes, such as cotyledon development, vein patterning and lateral root growth, were defective in the double homozygous vamp721 vamp722 mutant. Abnormal auxin distribution and root patterning were also observed in the mutant seedlings. Fluorescence imaging revealed that three auxin transporters, PIN-FORMED 1 (PIN1), PIN2 and AUXIN RESISTANT 1 (AUX1), aberrantly accumulate within the cytoplasm of the double mutant, impairing the polar localization at the plasma membrane (PM). Analysis of intracellular trafficking demonstrated the involvement of VAMP721 and VAMP722 in the endocytosis of FM4-64 and the secretion and recycling of the PIN2 transporter protein to the PM, but not its trafficking to the vacuole. Furthermore, vamp721 vamp722 mutant roots display enlarged trans-Golgi network (TGN) structures, as indicated by the subcellular localization of a variety of marker proteins and the ultrastructure observed using transmission electron microscopy. Thus, our results suggest that the R-SNAREs VAMP721 and VAMP722 mediate the post-Golgi trafficking of auxin transporters to the PM from the TGN subdomains, substantially contributing to plant growth.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas R-SNARE/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Transporte Biológico , Brefeldina A/farmacologia , Membrana Celular/metabolismo , Recuperação de Fluorescência Após Fotodegradação , Complexo de Golgi/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Proteínas R-SNARE/genéticaRESUMO
The dispersity of nonpolar nanoparticles (NPs) in water/ethanol mixed solvents was studied using molecular dynamics simulations. Based on the rule of "like dissolves like," nonpolar NPs should be dispersed better in a solvent with a lower polarity. As the mole fraction of ethanol in a mixed solvent (R) increases from 0% (pure water) to 100% (pure ethanol), the polarity of the mixed solvent is indicated to decrease monotonically. However, the dispersity of nonpolar NP does not increase monotonically: it first decreases after the addition of a small fraction of ethanol (R < 8.0%) and then markedly increases as R further grows. When there is a small amount of ethanol, the ethanol molecules around aggregated NPs tend to simultaneously make contact with multiple NPs, which can increase the tendency of NP aggregation. Furthermore, with a considerable ethanol ratio, the interaction of the solvent with NPs becomes notably strong, which facilitates the dissolution of NPs. Our findings may help to better understand the mechanism of dispersion of NPs in mixed solvents and may provide a useful precipitation technology for NP production.
RESUMO
The association between the ABO blood group and the risk of malaria during pregnancy has not been clearly established. The present study summarised relevant knowledge and reassessed the association through meta-analysis. Articles in MEDICINE and PubMed published before 30 November 2021 were searched. Five studies satisfied the inclusion criteria and were enrolled in the meta-analysis. It was shown that primiparae with different ABO blood group, multiparae with blood group A and non-A, AB and non-AB had a comparable risk of malaria. However, multiparae with blood group B had a significantly higher risk than non-B group [odds ratio (OR) = 1.23, 95% confidence interval (CI) was 1.01 to 1.50, P = 0.04], while multiparae with blood group O had a significantly lower risk than non-O group (OR = 0.78, 95% CI was 0.63 to 0.97, P = 0.03). Therefore, the ABO blood group may not result in a different risk of malaria in primiparae. Blood group B is potentially a risk factor while blood group O is a protective factor for multiparae.
Assuntos
Sistema ABO de Grupos Sanguíneos/fisiologia , Malária , Complicações Infecciosas na Gravidez , Feminino , Humanos , Malária/sangue , Malária/epidemiologia , Gravidez , Complicações Infecciosas na Gravidez/sangue , Complicações Infecciosas na Gravidez/epidemiologia , Fatores de RiscoRESUMO
Artificial intelligence (AI) is a branch of computer science that includes research in robotics, language recognition, image recognition, natural language processing, and expert systems. AI is poised to change medical practice, and oncology is not an exception to this trend. As the matter of fact, lung cancer has the highest morbidity and mortality worldwide. The leading cause is the complexity of associating early pulmonary nodules with neoplastic changes and numerous factors leading to strenuous treatment choice and poor prognosis. AI can effectively enhance the diagnostic efficiency of lung cancer while providing optimal treatment and evaluating prognosis, thereby reducing mortality. This review seeks to provide an overview of AI relevant to all the fields of lung cancer. We define the core concepts of AI and cover the basics of the functioning of natural language processing, image recognition, human-computer interaction and machine learning. We also discuss the most recent breakthroughs in AI technologies and their clinical application regarding diagnosis, treatment, and prognosis in lung cancer. Finally, we highlight the future challenges of AI in lung cancer and its impact on medical practice.
Assuntos
Inteligência Artificial , Neoplasias Pulmonares , Humanos , Aprendizado de Máquina , Prognóstico , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , PrevisõesRESUMO
The nonspecific binding of proteins with nanomaterials (NMs) is a dynamic reversible process including both protein adsorption and desorption parts, which is crucial for controlled release of protein drug loaded by nanocarriers. The nonspecific binding of proteins is susceptible to high temperature, whereas its underlying mechanism still remains elusive. Here, the binding behavior of human serum albumin (HSA) with an amino-terminated self-assembled monolayer (SAM)-coated gold (111) surface was investigated by using molecular dynamics (MD) simulations. HSA binds to the SAM surface through salt bridges at 300 K. As the temperature increases to 350 K, HSA maintains its native structure, while the salt bridges largely diminish owing to the considerable lateral diffusion of HSA on the SAM. Moreover, the interfacial water located between HSA and the SAM gets increased and prevents the reformation of the salt bridges of HSA with the SAM, which reduces the binding affinity of HSA. And HSA eventually desorbs from the SAM. The depiction of thermally induced spontaneous protein desorption enriches our understanding of reversible binding behavior of protein with NMs, and may provide new insights into the controlled release of protein drugs delivered by using nanocarriers under the regulation of high temperature.
Assuntos
Nanopartículas Metálicas/química , Albumina Sérica Humana/química , Adsorção , Ouro/química , Temperatura Alta , Humanos , Membranas Artificiais , Simulação de Dinâmica Molecular , Eletricidade Estática , Compostos de Sulfidrila/química , Água/químicaRESUMO
The evaporation of water nanofilms on a solid surface is a widespread and important process in many fields. Herein, we utilize molecular dynamics simulations to demonstrate that the evaporation of a water nanofilm is regulated by applying an alternating electric field (AEF). An AEF at a specific frequency can be resonantly absorbed by the water film. Consequently, the AEF with sufficient strength significantly increases the evaporation rate of the water film (R). In contrast, an AEF of a different frequency and polarization direction decreases R sharply, which is closely related to the strengthened hydrogen bond network and the reduced kinetic energy of the outermost water of the water film. When the maximum amplitude of the AEFs is 0.9 V/nm, which is achievable in a laboratory setting, R spans six orders of magnitude. The effects of applying the AEFs are quite distinct from those of changing the temperature. Notably, the polarization direction of the AEF plays an important role in the water evaporation. To the best of our knowledge, this is the first report on regulating the evaporation rate of a water film, showing that it is possible to use AEFs to tune the properties of nanoscaled water, such as the wettability.
RESUMO
Feature point matching is a key component in visual simultaneous localization and mapping (VSLAM). Recently, the neural network has been employed in the feature point matching to improve matching performance. Among the state-of-the-art feature point matching methods, the SuperGlue is one of the top methods and ranked the first in the CVPR 2020 workshop on image matching. However, this method utilizes graph neural network (GNN), resulting in large computational complexity, which makes it unsuitable for resource-constrained devices, such as robots and mobile phones. In this work, we propose a lightweight feature point matching method based on the SuperGlue (named as AdaSG). Compared to the SuperGlue, the AdaSG adaptively adjusts its operating architecture according to the similarity of input image pair to reduce the computational complexity while achieving high matching performance. The proposed method has been evaluated through the commonly used datasets, including indoor and outdoor environments. Compared with several state-of-the-art feature point matching methods, the proposed method achieves significantly less runtime (up to 43× for indoor and up to 6× for outdoor) with similar or better matching performance. It is suitable for feature point matching in resource constrained devices.