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1.
J Phys Chem Lett ; : 10560-10569, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39401312

RESUMO

The issues of zinc dendrites and side reactions caused by active water molecules have seriously affected the development of aqueous zinc batteries (AZBs). Herein, a symmetry hydrogen-bond donor-acceptor molecule additive named 1,3-bis(hydroxymethyl)urea (BHMU) can preferentially adsorb on the anode surface and lock up water molecules through hydrogen bonding, thus isolating water molecules and reducing side reactions caused by active water molecules. With these advantages, the mixed electrolyte containing BHMU additive impels a reversible Zn anode with a high Coulombic efficiency (99.7% over 1000 cycles at 1 mA cm-2), while it also enables a stable symmetric cell operated at 1 mA cm-2 (1 mAh cm-2, 6.89% DODZn) for 2250 h and 10 mA cm-2 (10 mAh cm-2, 68.9% DODZn) for 350 h. More importantly, the Zn||PTO full battery also delivered superior cycling stability and higher capacity after 3000 consecutive 3000 cycles of circulation at 5 A g-1. This study has great significance for the use of symmetry donor-acceptor molecules to modulate the solvation structure and the interface stability of the Zn anode in aqueous electrolytes.

2.
Small ; : e2405193, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39252656

RESUMO

Surface-enhanced Raman scattering (SERS) is widely used in all kinds of detection due to its ultrahigh sensitivity and selectivity. Micromotors, when used as SERS sensors, or the so-called "hotspots on the fly", can combine both controlled mobility and SERS sensing capacity, and are ideal for versatile in situ detection. In this work, mobile SERS sensors are successfully fabricated by growing gold nanospikes onto magnetic microsphere surfaces. These mobile micromotors can act as normal SERS sensors, characterized by the trace detection of thiram, a highly toxic fungicide. The detection limit can reach 0.1 nM, as good as most other noble metal deposited substrates. With significant magnetic gradient forces, separation of pathogenic bacteria from bulk solution is achieved once these magnetic micromotors bind with bacterial cells. Manipulated propulsion of micromotors, on the other hand, enables them to approach and contact pathogenic bacterial cells on command and further acquire Raman spectra under a controlled degree of contact, a capability never seen with passive sensors. The robotic SERS sensors have demonstrated unique sensing characteristics with controlled manipulations along with discriminative detection between bacterial species.

3.
Ecotoxicol Environ Saf ; 284: 116877, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39142118

RESUMO

Citrinin (CTN) is a mycotoxin commonly found in contaminated foods and feed, posing health risks to both humans and animals. However, the mechanism by which CTN damages the intestine remains unclear. In this study, a model of intestinal injury was induced by administering 1.25 mg/kg and 5 mg/kg of CTN via gavage for 28 consecutive days in 6-week-old Kunming mice, aiming to explore the potential mechanisms underlying intestinal injury. The results demonstrate that CTN can cause structural damage to the mouse jejunum. Additionally, CTN reduces the protein expression of Claudin-1, Occludin, ZO-1, and MUC2, thereby disrupting the physical and chemical barriers of the intestine. Furthermore, exposure to CTN alters the structure of the intestinal microbiota in mice, thus compromising the intestinal microbial barrier. Meanwhile, the results showed that CTN exposure could induce excessive apoptosis in intestinal cells by altering the expression of proteins such as CHOP and GRP78 in the endoplasmic reticulum and Bax and Cyt c in mitochondria. The mitochondria and endoplasmic reticulum are connected through the mitochondria-associated endoplasmic reticulum membrane (MAM), which regulates the membrane. We found that the expression of bridging proteins Fis1 and BAP31 on the membrane was increased after CTN treatment, which would exacerbate the endoplasmic reticulum dysfunction, and could activate proteins such as Caspase-8 and Bid, thus further inducing apoptosis via the mitochondrial pathway. Taken together, these results suggest that CTN exposure can cause intestinal damage by disrupting the intestinal barrier and inducing excessive apoptosis in intestinal cells.


Assuntos
Apoptose , Citrinina , Chaperona BiP do Retículo Endoplasmático , Retículo Endoplasmático , Mucosa Intestinal , Mitocôndrias , Animais , Citrinina/toxicidade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Camundongos , Apoptose/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Microbioma Gastrointestinal/efeitos dos fármacos , Ocludina/metabolismo , Intestinos/efeitos dos fármacos , Intestinos/patologia , Jejuno/efeitos dos fármacos , Jejuno/patologia , Animais não Endogâmicos
4.
Ecotoxicol Environ Saf ; 284: 116946, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39208586

RESUMO

Citrinin (CTN) has been reported to induce renal failure and structural damage, but its nephrotoxic effects and mechanisms are not fully understood. Therefore, we established a model by orally administering CTN (0, 1.25, 5, or 20 mg/kg) to mice for 21 consecutive days. Histological and biochemical analyses revealed that CTN caused structural damage to renal tubules, increased inflammatory cell infiltration, and elevated levels of serum markers of renal function (creatinine, urea, and uric acid). Moreover, mRNA transcript levels of the inflammatory factors TNF-α, IL-1ß, and IL-6 were increased, indicating the occurrence of an inflammatory response. Furthermore, exposure to CTN induced renal oxidative stress by decreasing antioxidant GSH levels, antioxidant enzyme (SOD, CAT) activities, and increasing oxidative products (ROS, MDA). In addition, CTN increased the expression of proteins associated with endoplasmic reticulum (ER)stress and apoptotic pathways. ER stress has been shown to be involved in regulating various models of kidney disease, but its role in CTN-induced renal injury has not been reported. We found that pretreatment with the ER stress inhibitor 4-PBA (240 mg/kg, ip) alleviated CTN-induced oxidative stress, NF-κB pathway mediated inflammatory response, and apoptosis. Interestingly, 4-PBA also partially alleviated renal structural damage and dysfunction. Thus, ER stress may be a novel target for the prevention and treatment of CTN-induced renal injury.


Assuntos
Apoptose , Citrinina , Estresse do Retículo Endoplasmático , Inflamação , Estresse Oxidativo , Animais , Estresse Oxidativo/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Citrinina/toxicidade , Camundongos , Inflamação/induzido quimicamente , Inflamação/patologia , Masculino , Rim/efeitos dos fármacos , Rim/patologia , Nefropatias/induzido quimicamente , Nefropatias/patologia
5.
Comput Biol Med ; 180: 108985, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39142224

RESUMO

BACKGROUND: Chrysanthemi Flos as a medicine food homology species is widely used in the prevention and treatment of diseases, whereas comprehensive research of its active compounds related to multi-pharmacological effects remains limited. This study aimed to systematically explore the active compounds through artificial intelligence-based target prediction and activity evaluation. METHODS: The information on compounds in Chrysanthemi Flos was obtained from six cultivars containing Gongju, Chuju, Huaiju, Boju, Hangbaiju, and Fubaiju, using UPLC-Q-TOF/MS. The main differential metabolites in six cultivars were also screened through the PLS-DA model. Then the potential targets of differential compounds were predicted via the DrugBAN model. Enrichment and topological analysis of compound-target networks were performed to identify key pharmaceutical compounds. Subsequently, the pharmacological effects of predictively active compounds were confirmed in vitro. Based on the active compounds, the pharmacological activities of Chrysanthemi Flos from the six origins were also investigated and compared for the further evaluation of medicinal quality. RESULTS: A total of 155 secondary metabolites were obtained from Chrysanthemi Flos. Among them, 26 differential components were screened, and 9 key pharmacological compounds with 1141 targets were identified. Enrichment analysis indicated the main pharmacological effects of Chrysanthemi Flos related to inflammation, oxidative stress, and lipid metabolism. In addition, 9 key pharmaceutical compounds were evaluated in vitro experiments, indicating the significant therapeutic effect in regulating inflammation, oxidative stress, and lipid metabolism. CONCLUSION: This study successfully identified 9 key pharmaceutical compounds in Chrysanthemi Flos and predicted the pharmacodynamic advantages of six origins. The findings would provide improved guidance for the discovery of active constituents and the assessment of pharmacodynamic advantages of different geographical origins.


Assuntos
Inteligência Artificial , Chrysanthemum , Medicamentos de Ervas Chinesas , Flores , Chrysanthemum/química , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Flores/química , Humanos
6.
Materials (Basel) ; 17(15)2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39124307

RESUMO

Existing optimization research on the crankshaft heat treatment process is mostly based on one-sided considerations, and less consideration is given to the matching of multiple process parameters, leading to irrational designs of heat treatment. To address this problem, this work investigates the influence mechanisms of cooling speed, tempering temperature, and holding time on the performance evaluation indexes of the straightness, residual stress, and martensite content of a crankshaft based on the response surface method. The results showed that the order of influence of these three different process parameters on the performance evaluation index was cooling speed > holding time > tempering temperature, and the order of influence on the performance evaluation indexes under multifactorial process parameters was cooling speed-holding time > cooling speed-tempering temperature > holding time-tempering temperature. The optimal process parameters were a cooling speed of 1.4 times the cooling oil, a tempering temperature of 555 °C, and a holding time of 6 h, with the straightness of the crankshaft reduced by 9.9%, the surface stress increased by 6.7%, and the martensitic content increased by 7.2% after the process optimization. This work can provide new clues for optimizing the heat treatment process parameters of crankshafts.

7.
Ecotoxicol Environ Saf ; 283: 116787, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-39067079

RESUMO

T-2 toxin, a mycotoxin found in foods and feeds, poses a threat to female reproductive health in both humans and animals. LncRNA CUFF.253988.1 (CUFF.253988.1), highly expressed in pigs, has an undisclosed regulatory role. This study aimed to establish a model of T-2 toxin-induced ovarian injury in sows, both in vivo and in vitro, and to explore the regulatory role and potential mechanisms of CUFF.253988.1. The results showed that feeding T-2 toxin-contaminated feed (1 mg/kg) induced ovarian follicle atresia and mitochondrial structural damage, accompanied by a significant upregulation of CUFF.253988.1 expression in the ovaries. Additionally, T-2 toxin inhibited the SIRT3/PGC1-α pathway associated with mitochondrial function. Moreover, T-2 toxin induced cell apoptosis by upregulating the expression of Cyt c, Bax, cleaved-caspase-9, and cleaved-caspase-3 proteins. In T-2 toxin-induced injury to the ovarian granulosa AVG-16 cells at concentrations of 10, 40 and 160 nM, not only were the previously mentioned effects observed, but also a decrease in mitochondrial membrane potential, ATP content, and an elevation in ROS levels. However, downregulating CUFF.253988.1 reversed T-2 toxin's inhibition of the SIRT3/PGC1-α pathway, alleviating mitochondrial dysfunction and reducing cell apoptosis. Notably, this may be attributed to the inhibition of T-2 toxin-induced enrichment of CUFF.253988.1 in mitochondria. In conclusion, CUFF.253988.1 plays a pivotal role in T-2 toxin-induced ovarian damage, operating through the inhibition of the SIRT3/PGC1-α pathway and promotion of cell apoptosis.


Assuntos
Apoptose , Ovário , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , RNA Longo não Codificante , Sirtuína 3 , Toxina T-2 , Animais , Feminino , Apoptose/efeitos dos fármacos , Toxina T-2/toxicidade , Sirtuína 3/genética , Sirtuína 3/metabolismo , Suínos , RNA Longo não Codificante/genética , Ovário/efeitos dos fármacos , Ovário/patologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Células da Granulosa/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
8.
J Environ Manage ; 364: 121450, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38875987

RESUMO

To trace the origin of the gushing water in the riverine area of the Beijing section of The Middle Route of South-to-North Water Diversion Project, a dataset was established comprising water chemistry, three-dimensional fluorescence spectra, and stable isotopes for different water bodies. Results indicated significant differences in Electrical Conductivity (EC), Total Dissolved Solids (TDS), and Ca2+ concentration among the gushing water, river water, and the water from the Middle Route of South-to-North Water Diversion Project (MRSD). Analysis using parallel factor analysis (PARAFAC) and fluorescence index revealed that dissolved organic matter (DOM) in the MRSD mainly originated from endogenous sources, while the river water and gushing water showed influences from both endogenous and exogenous sources. Nitrate sources varied among the water bodies, with distinct contributions from domestic sewage and fertilizer sources. The evaporation lines of river water and gushing water exhibited similar intercepts and slopes, but their intercepts and slopes are much smaller than those of the MRSD, suggesting stronger kinetic evaporative fractionation. In conclusion, the gushing water in the riverine area of the MRSD was determined to originate from the river, providing a fast and efficient method for gushing water source identification.


Assuntos
Rios , Rios/química , Pequim , Monitoramento Ambiental , China , Poluentes Químicos da Água/análise
9.
J Chem Inf Model ; 64(17): 6736-6744, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-38829968

RESUMO

The design of nanozymes with superior catalytic activities is a prerequisite for broadening their biomedical applications. Previous studies have exerted significant effort in theoretical calculation and experimental trials for enhancing the catalytic activity of nanozyme. Machine learning (ML) provides a forward-looking aid in predicting nanozyme catalytic activity. However, this requires a significant amount of human effort for data collection. In addition, the prediction accuracy urgently needs to be improved. Herein, we demonstrate that ChatGPT can collaborate with humans to efficiently collect data. We establish four qualitative models (random forest (RF), decision tree (DT), adaboost random forest (adaboost-RF), and adaboost decision tree (adaboost-DT)) for predicting nanozyme catalytic types, such as peroxidase, oxidase, catalase, superoxide dismutase, and glutathione peroxidase. Furthermore, we use five quantitative models (random forest (RF), decision tree (DT), Support Vector Regression (SVR), gradient boosting regression (GBR), and fully connected deep neuron network (DNN)) to predict nanozyme catalytic activities. We find that GBR model demonstrates superior prediction performance for nanozyme catalytic activities (R2 = 0.6476 for Km and R2 = 0.95 for Kcat). Moreover, an open-access web resource, AI-ZYMES, with a ChatGPT-based nanozyme copilot is developed for predicting nanozyme catalytic types and activities and guiding the synthesis of nanozyme. The accuracy of the nanozyme copilot's responses reaches more than 90% through the retrieval augmented generation. This study provides a new potential application for ChatGPT in the field of nanozymes.


Assuntos
Aprendizado de Máquina , Catálise , Árvores de Decisões , Humanos , Enzimas/metabolismo , Enzimas/química
10.
Adv Mater ; 36(29): e2311470, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38760007

RESUMO

Layers of nanometer thick polydimethylsiloxane (PDMS) are applied as hydrophobic coatings because of their environmentally friendly and chemically inert properties. In applications such as heat exchangers or fog harvesting, low water drop friction on surfaces is required. While the onset of motion (static friction) has been studied, the knowledge of dynamic friction needs to be improved. To minimize drop friction, it is essential to understand which processes lead to energy dissipation and cause dynamic friction? Here, the dynamic friction of drops on PDMS brushes of different thicknesses is measured, covering the whole available velocity regime. The brush thickness L turns out to be a predictor for drop friction. 4-5 nm thick PDMS brush shows the lowest dynamic friction. A certain minimal thickness is necessary to form homogeneous surfaces and reduce the attractive van der Waals interaction between water and the substrate. The increase in dynamic friction above L = 5 nm is also attributed to the increasing viscoelastic dissipation of the capillary ridge formed at the contact line. The height of the ridge is related to the brush thickness. Fluorescence correlation spectroscopy and atomic force measurements support this interpretation. Sum-frequency generation further indicates a maximum order at the PDMS-water interface at intermediate thickness.

11.
Nat Commun ; 15(1): 2947, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580680

RESUMO

Intrinsic polymer room-temperature phosphorescence (IPRTP) materials have attracted considerable attention for application in flexible electronics, information encryption, lighting displays, and other fields due to their excellent processabilities and luminescence properties. However, achieving multicolor long-lived luminescence, particularly white afterglow, in undoped polymers is challenging. Herein, we propose a strategy of covalently coupling different conjugated chromophores with poly(acrylic acid (AA)-AA-N-succinimide ester) (PAA-NHS) by a simple and rapid one-pot reaction to obtain pure polymers with long-lived RTPs of various colors. Among these polymers, the highest phosphorescence quantum yield of PAPHE reaches 14.7%. Furthermore, the afterglow colors of polymers can be modulated from blue to red by introducing three chromophores into them. Importantly, the acquired polymer TPAP-514 exhibits a white afterglow at room temperature with the chromaticity coordinates (0.33, 0.33) when the ratio of chromophores reaches a suitable value owing to the three-primary-color mechanism. Systematic studies prove that the emission comes from the superposition of different triplet excited states of the three components. Moreover, the potential applications of the obtained polymers in light-emitting diodes and dynamic anti-counterfeiting are explored. The proposed strategy provides a new idea for constructing intrinsic polymers with diverse white-light emission RTPs.

12.
Heliyon ; 10(7): e28730, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38586336

RESUMO

Background: Metamycoplasma orale (M.orale), a symbiotic bacterium observed in the human oral cavity, is generally regarded as non-pathogenic to humans. Although infrequent, symptomatic infections caused by M.orale may occur in individuals with compromised humoral immunity. Accurate identification and early diagnosis of M.orale still present significant challenges due the limitations associated with conventional detection methods. Although metagenomic next-generation sequencing (mNGS) is currently widely utilized in clinical practices and exhibits a remarkable specificity and sensitivity for detecting various pathogens, its application in the diagnosis of M.orale-induced osteomyelitis remains largely unexplored. Case description: In this report, we present a case study of osteonecrosis caused by M.orale in a 20-year-old female patient with nephrotic syndrome and other comorbidities. She was administered long-term hormone therapy and immunosuppressants, leading to her admission to the hospital due to recurrent fever, hip abscess and left thigh pain. Imaging examination revealed bilateral mid-femoral lesions, with the extensive nature of the left femoral lesion suggesting a potential secondary infection. Although no pathogen was detected in pus culture, mNGS analysis identified M.orale in the sample. Following treatment with doxycycline and levofloxacin, the patient's symotoms improved and she was discharged with favorable outcomes. Conclusion: mNGS enables rapid identification of etiology in patients with osteomyelitis caused by the rare pathogen M.orale. This case accentuate the strength of mNGS for early detection and targeted clinical treatment of infectious diseases caused by uncommon pathogens.

13.
Small ; 20(34): e2312275, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38573924

RESUMO

High internal phase emulsions (HIPEs) have been of great interest for fabricating fluorinated porous polymers having controlled pore structures and excellent physicochemical properties. However, it remains a challenge to prepare stable fluorocarbon HIPEs, due to the lack of suitable surfactants. By randomly grating hydrophilic and fluorophilic side chains to polyphosphazene (PPZ), a comb-like amphiphilic PPZ surfactant with biodegradability is designed and synthesized for stabilizing water/fluorocarbon oil-based emulsions. The hydrophilic-lipophilic balance of PPZs can be controlled by tuning the grating ratio of the two side chains, leading to the preparation of stable water-in-oil HIPEs and oil-in-water emulsions, and the production of fluorinated porous polymers and particles by polymerizing the oil phase. These fluorinated porous polymers show excellent thermal stability and, due to the hydrophobicity and porous structure, applications in the field of oil/water separation can be achieved.

14.
J Phys Chem Lett ; 15(17): 4669-4678, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38651977

RESUMO

The Zn dendrite and hydrogen evolution reaction have been a "stubborn illness" for the life span of zinc anodes, which significantly hinders the development of aqueous zinc batteries (AZBs). Herein, considering the ingenious molecular structure, a multifunctional additive based on the synergistic regulation of cations and anions at the interface is designed to promote a dendrite-free and stable Zn anode. Theoretical calculations and characterization results verified that the electrostatic shield effect of the cation, the solvation sheath structure, and the bilayer structural solid electrolyte film (SEI) jointly account for the uniform Zn deposition and side reaction suppression. Ultimately, a remarkably high average Coulombic efficiency (CE) of 99.4% is achieved in the Zn||Cu cell for 300 cycles, and a steady charge/discharge cycling over 3000 and 300 h at 1.0 mA cm-2/1.0 mAh cm-2 and 10 mA cm-2/10 mAh cm-2 is obtained in the Zn||Zn cell. Furthermore, the assembled full battery demonstrates a prolonged cycle life of 2000 cycles.

15.
Front Plant Sci ; 15: 1313832, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38525146

RESUMO

High temperatures affect grape yield and quality. Grapes can develop thermotolerance under extreme temperature stress. However, little is known about the changes in transcription that occur because of high-temperature stress. The heat resistance indices and transcriptome data of five grape cultivars, 'Xinyu' (XY), 'Miguang' (MG), 'Summer Black' (XH), 'Beihong' (BH), and 'Flame seedless' (FL), were compared in this study to evaluate the similarities and differences between the regulatory genes and to understand the mechanisms of heat stress resistance differences. High temperatures caused varying degrees of damage in five grape cultivars, with substantial changes observed in gene expression patterns and enriched pathway responses between natural environmental conditions (35 °C ± 2 °C) and extreme high temperature stress (40 °C ± 2 °C). Genes belonging to the HSPs, HSFs, WRKYs, MYBs, and NACs transcription factor families, and those involved in auxin (IAA) signaling, abscisic acid (ABA) signaling, starch and sucrose pathways, and protein processing in the endoplasmic reticulum pathway, were found to be differentially regulated and may play important roles in the response of grape plants to high-temperature stress. In conclusion, the comparison of transcriptional changes among the five grape cultivars revealed a significant variability in the activation of key pathways that influence grape response to high temperatures. This enhances our understanding of the molecular mechanisms underlying grape response to high-temperature stress.

16.
J Chem Phys ; 160(11)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38506293

RESUMO

Unsaturated lipids with C=C groups in their alkyl chains are widely present in the cell membrane and food. The C=C groups alter the lipid packing density, membrane stability, and persistence against lipid oxidation. Yet, molecular-level insights into the structure of the unsaturated lipids remain scarce. Here, we probe the molecular structure and organization of monolayers of unsaturated lipids on the water surface using heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. We vary the location of the C=C in the alkyl chain and find that at high lipid density, the location of the C=C group affects neither the interfacial water organization nor the tail of the alkyl chain. Based on this observation, we use the C=C stretch HD-SFG response to depth-profile the alkyl chain conformation of the unsaturated lipid. We find that the first 1/3 of carbon atoms from the headgroup are relatively rigid, oriented perpendicular to the surface. In contrast, the remaining carbon atoms can be approximated as free rotators, introducing the disordering of the alkyl chains.

17.
Angew Chem Int Ed Engl ; 63(20): e202319503, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38478726

RESUMO

Graphene, a transparent two-dimensional conductive material, has brought extensive new perspectives and prospects to various aqueous technological systems, such as desalination membranes, chemical sensors, energy storage, and energy conversion devices. Yet, the molecular-level details of graphene in contact with aqueous electrolytes, such as water orientation and hydrogen bond structure, remain elusive or controversial. Here, we employ surface-specific heterodyne-detected sum-frequency generation (HD-SFG) vibrational spectroscopy to re-examine the water molecular structure at a freely suspended graphene/water interface. We compare the response from the air/graphene/water system to that from the air/water interface. Our results indicate that the χ y y z 2 ${{\chi }_{yyz}^{\left(2\right)}}$ spectrum recorded from the air/graphene/water system arises from the topmost 1-2 water layers in contact with the graphene, with the graphene itself not generating a significant SFG response. Compared to the air/water interface response, the presence of monolayer graphene weakly affects the interfacial water. Graphene weakly affects the dangling O-H group, lowering its frequency through its interaction with the graphene sheet, and has a very small effect on the hydrogen-bonded O-H group. Molecular dynamics simulations confirm our experimental observation. Our work provides molecular insight into the interfacial structure at a suspended graphene/water interface, relevant to various technological applications of graphene.

18.
Biomed Pharmacother ; 173: 116273, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38412715

RESUMO

Osteoarthritis (OA) is a degenerative joint disease, Increasingly, mitochondrial autophagy has been found to play an important regulatory role in the prevention and treatment of osteoarthritis. Koumine is a bioactive alkaloid extracted from the plant Gelsemium elegans. In previous research, Koumine was found to have potential in improving the progression of OA in rats. However, the specific mechanism of its action has not been fully explained. Therefore, the aim of this study was to investigate whether Koumine can alleviate OA in rats by influencing mitochondrial autophagy. In the in vitro study, rat chondrocytes (RCCS-1) were induced with IL-1ß (10 ng/mL) to induce inflammation, and Koumine (50 µg/mL) was co-treated. In the in vivo study, a rat OA model was established by intra-articular injection of 2% papain, and Koumine was administered orally (1 mg/kg, once daily for two weeks). It was found that Koumine effectively reduced cartilage erosion in rats with osteoarthritis. Additionally, it decreased the levels of inflammatory factors such as IL-1ß, IL-6, and extracellular matrix (ECM) components MMP13 and ADAMTS5 in chondrocytes and articular cartilage tissue, while increasing the level of Collagen II.Koumine inhibited the production of reactive oxygen species (ROS) in cartilage tissue and increased the number of autophagosomes in chondrocytes and articular cartilage tissue. Additionally, it upregulated the expression of mitochondrial autophagy proteins LC3Ⅱ/Ⅰ, PINK1, Parkin, and Drp1. The administration of Mdivi-1 (50 µM) reversed the enhanced effect of Koumine on mitochondrial autophagy, as well as its anti-inflammatory and anti-ECM degradation effects in rats with OA. These findings suggest that Koumine can alleviate chondrocyte inflammation and improve the progression of OA in rats by activating PINK1/Parkin-mediated mitochondrial autophagy.


Assuntos
Cartilagem Articular , Alcaloides Indólicos , Osteoartrite , Ratos , Animais , Condrócitos/metabolismo , Osteoartrite/tratamento farmacológico , Osteoartrite/metabolismo , Ratos Sprague-Dawley , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Cartilagem Articular/metabolismo , Autofagia , Interleucina-1beta/metabolismo , Matriz Extracelular/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Quinases/metabolismo
19.
Int Immunopharmacol ; 129: 111653, 2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38354511

RESUMO

T-2 toxin, an unavoidable contaminant in animal feeds, can induce oxidative stress and damage immune organs. Melatonin (MT), a natural and potent antioxidant, has shown promise as a detoxifier for various mycotoxins. However, the detoxifying effect of MT on T-2 toxin has not been previously reported. In order to investigate the protective effect of MT added to diets on the immune system of T-2 toxin-exposed piglets, twenty piglets weaned at 28d of age were randomly divided into control, T-2 toxin (1 mg/kg), MT (5 mg/kg), and T-2 toxin (1 mg/kg) + MT (5 mg/kg) groups(n = 5 per group). Our results demonstrated that MT mitigated T-2 toxin-induced histoarchitectural alterations in the spleen and thymus, such as hemorrhage, decreased white pulp size in the spleen, and medullary cell sparing in the thymus. Further research revealed that MT promoted the expression of Nrf2 and increased the activities of antioxidant enzymes CAT and SOD, while reducing the production of the lipid peroxidation product MDA. Moreover, MT inhibited the NF-κB signaling pathway, regulated the expression of downstream cytokines IL-1ß, IL-6, TNF-α, and TGF-ß1. MT also suppressed the activation of caspase-3 while down-regulating the ratio of Bax/Bcl-2 to reduce apoptosis. Additionally, MT ameliorated the T-2 toxin-induced disorders of immune cells and immune molecules in the blood. In conclusion, our findings suggest that MT may effectively protect the immune system of piglets against T-2 toxin-induced damage by inhibiting oxidative stress, inflammatory response, and apoptosis in the spleen and thymus. Therefore, MT holds the potential as an antidote for T-2 toxin poisoning.


Assuntos
Melatonina , Toxina T-2 , Animais , Suínos , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Antioxidantes/metabolismo , Melatonina/farmacologia , Melatonina/uso terapêutico , Melatonina/metabolismo , Baço , Toxina T-2/toxicidade , Estresse Oxidativo , Apoptose
20.
Phys Rev Lett ; 132(5): 056203, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38364171

RESUMO

Friction is responsible for about one-third of the primary energy consumption in the world. So far, a thorough atomistic understanding of the frictional energy dissipation mechanisms is still lacking. The Amontons' law states that kinetic friction is independent of the sliding velocity while the Prandtl-Tomlinson model suggests that damping is proportional to the relative sliding velocity between two contacting objects. Through careful analysis of the energy dissipation process in atomic force microscopy measurements, here we propose that damping force is proportional to the tip oscillation speed induced by friction. It is shown that a physically well-founded damping term can better reproduce the multiple peaks in the velocity-dependent friction force observed in both experiments and molecular dynamics simulations. Importantly, the analysis gives a clear physical picture of the dynamics of energy dissipation in different friction phases, which provides insight into long-standing puzzles in sliding friction, such as velocity weakening and spring-stiffness-dependent friction.

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