Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
Entropy (Basel) ; 26(4)2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38667869

RESUMO

Network security situational awareness (NSSA) aims to capture, understand, and display security elements in large-scale network environments in order to predict security trends in the relevant network environment. With the internet's increasingly large scale, increasingly complex structure, and gradual diversification of components, the traditional single-layer network topology model can no longer meet the needs of network security analysis. Therefore, we conduct research based on a multi-layer network model for network security situational awareness, which is characterized by the three-layer network structure of a physical device network, a business application network, and a user role network. Its network characteristics require new assessment methods, so we propose a multi-layer network link importance assessment metric: the multi-layer-dependent link entropy (MDLE). On the one hand, the MDLE comprehensively evaluates the connectivity importance of links by fitting the link-local betweenness centrality and mapping entropy. On the other hand, it relies on the link-dependent mechanism to better aggregate the link importance contributions in each network layer. The experimental results show that the MDLE has better ordering monotonicity during critical link discovery and a higher destruction efficacy in destruction simulations compared to classical link importance metrics, thus better adapting to the critical link discovery requirements of a multi-layer network topology.

2.
Front Cardiovasc Med ; 11: 1356134, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38481953

RESUMO

Background: Primary cardiac lymphoma is an extremely rare malignant lymphoma, with clinical manifestations related to its location. We reported the diagnosis and treatment of primary cardiac lymphoma in a patient presented with atrioventricular block. Case presentation: A 64 year-old man was admitted to our hospital because of symptoms of a tired heart and shortness of breath. The initial electrocardiogram revealed a third-degree atrioventricular block. Computed tomography scan showed an irregularly shaped right heart, irregular clusters, and relatively weakly enhanced areas in the right auricle, atrium, and ventricle. The local boundary between the lesion, pericardium, and left atrium was unclear, and the ventricular septum was irregular and thickened. Multiple irregular gray neoplasms with less smooth surfaces were observed, with a maximum diameter of approximately 7 cm. Pathological findings confirmed a non-germinal center B cell subtype of diffuse large B-cell lymphoma. After surgical resection of the tumor and implantation of a permanent pacemaker, the symptoms of the patient were significantly improved, allowing subsequent chemotherapy. Conclusion: Surgical resection and placement of a permanent pacemaker were effective treatments for a patient with primary cardiac lymphoma presented with atrioventricular block.

3.
Exp Ther Med ; 27(2): 85, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38274340

RESUMO

The present study described the case of a 22-year-old woman who had symptoms of left chest pain for >6 months, with further aggravation over 2 days. Computed tomography (CT) images of the mediastinal and pulmonary windows showed low-density shadows in the left ventricle. Echocardiography indicated a slightly stronger echo cluster in the left ventricle, with a range of ~29x30x35 mm, which was closely related to the lower wall and part of the posterior wall of the left ventricle. Contrast-enhanced ultrasound showed that the left ventricular mass was enhanced in a circular and dot-line shape, with a solid mass occupying the left ventricle and a rich blood supply. CT angiography revealed a nodule of size 27x27x24 mm in the left ventricle. During the operation, it was observed that the cardiac lipoma invaded the chordae tendinae and papillary muscle, and a valve replacement was performed. Postoperative examination revealed a piece of gray and anaplastic tissue, measuring 30x22x17 mm. The pathology of the specimen showed that the morphology of the left ventricular mass met the criteria of an intramuscular lipoma. The present study reported a cardiac lipoma involving the left anterior chordae tendinae and papillary muscle, with the patient showing only nonspecific symptoms. Early surgery should be applied to improve the prognosis of cardiac lipoma.

4.
Biosens Bioelectron ; 249: 116016, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38217967

RESUMO

Early chronic kidney disease (CKD) has strong concealment and lacks an efficient, non-invasive, and lable-free detection platform. Cystatin C (Cys C) in urine is closely related to the progress of CKD (especially at the early stage), which is an ideal endogenous marker to evaluate the impairment of renal function. Thus, the accurate detection of urinary Cys C (u-Cys C) is great significant for early prevention and treatment and delaying the course of the disease of CKD patients. Herein, we developed an extended-gate field-effect transistor (EG-FET) sensor for ultrasensitive detection of u-Cys C, which consists of a monolithic interface-engineered graphene EG electrode array and a commercially available MOSFET. Laser-induced graphene (LIG) loaded with sputtered Au NPs in the presence of adhesive Cr (Au NPs/Cr/LIG) boosts the electrical performance of the EG electrode. Meanwhile, Au NPs also serve as linkers to immobilize papain that can selectively form protein complexes with Cys C. Supported by the synergistic effect of multilevel interface-engineered graphene, our sensor exhibits a good linear correlation within the u-Cys C concentration range of 5 ag/µL to 50 ng/µL with low detection limit of 0.05 ag/µL. Our work makes accurate, specific and rapid detection of u-Cys C feasible and promising for early screening for CKD.


Assuntos
Técnicas Biossensoriais , Líquidos Corporais , Grafite , Insuficiência Renal Crônica , Humanos , Cistatina C/urina , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/urina
5.
J Agric Food Chem ; 71(50): 20155-20166, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38051952

RESUMO

Juvenile hormone III (JH III) is a crucial hormone synthesized exclusively as R-stereoisomer in most insects. Herein, we established a mature Tris-HCl culture system for essential biochemical reactions and applied stable instrumental detection methods to analyze JH III, methyl farnesoate (MF) and juvenile hormone acid (JHA) using UPLC-MS/MS. Our results revealed that the R-JH III terminal synthesis pathway in Apis mellifera follows the "esterify then epoxidize" sequence, with precise methyl-(2E,6E)-farnesoate titer regulation and its spatial cis-trans isomerism, achieving selective R-JH III synthesis. Furthermore, we observed that the preferred generation of S/R-JH III chiral enantiomers varied depending on the spatial cis-trans isomerism of different MFs. Our results suggest that S-JH III could theoretically exist in insects, offering a novel perspective for understanding the synthesis mechanism of diverse complex juvenile hormones in different insect species.


Assuntos
Hormônios Juvenis , Espectrometria de Massas em Tandem , Abelhas , Animais , Estereoisomerismo , Cromatografia Líquida , Insetos
6.
Pestic Biochem Physiol ; 197: 105653, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38072528

RESUMO

Allatostatin (AS) or Allatotropin (AT) is a class of insect short neuropeptide F (sNPF) that affects insect growth and development by inhibiting or promote the synthesis of juvenile hormone (JH) in different insects. III-2 is a novel sNPF analog derived from a group of nitroaromatic groups connected by different amino acids. In this study, we found that III-2 showed high insecticidal activity against S. frugiperda larvae with a LC50 of 18.7 mg L-1. As demonstrated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), III-2 particularly facilitated JH III and hindered 20E synthesis in S. frugiperda. The results of RNA-Seq and quantitative real-time polymerase chain reaction (qPCR) showed that III-2 treatment promoted the expression of key genes such as SfCYP15C1 in JH synthesis pathway and inhibited the expression of SfCYP314A1 and other genes in the 20E synthetic pathway. Significant differences were also observed in the expression of the genes related to cuticle formation. We report for the first time that sNPF compounds specifically interfere with the synthesis and secretion of a certain JH in insects, thus affecting the ecdysis and growth of insects, and leading to death. This study may provide a new plant conservation concept for us to seek the targeted control of certain insects based on specific interference with different JH.


Assuntos
Hormônios Juvenis , Espectrometria de Massas em Tandem , Animais , Spodoptera/genética , Spodoptera/metabolismo , Cromatografia Líquida , Hormônios Juvenis/farmacologia , Hormônios Juvenis/metabolismo , Larva/metabolismo , Insetos
7.
Pestic Biochem Physiol ; 196: 105594, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37945244

RESUMO

The toxic effects of neonicotinoid pesticides on honeybees is a global concern, whereas little is known about the effect of stereoisomeric pesticides among honeybee social behavior. In this study, we investigated the effects of stereoisomeric dinotefuran on honeybee social behavior. We found that honeybees exhibit a preference for consuming food containing S-dinotefuran, actively engage in trophallaxis with S-dinotefuran-consuming peers, and consequently acquire higher levels of S-dinotefuran compared with R-dinotefuran. In comparison to R-dinotefuran, S-dinotefuran stimulates honeybees to elevate their body temperature, thereby attracting more peers for trophallaxis. Transcriptome analysis revealed a significant enrichment of thermogenesis pathways due to S-dinotefuran exposure. Additionally, metabolome data indicated that S-dinotefuran may enhance body temperature by promoting lipid synthesis in the lysine degradation pathway. Consequently, body temperature emerges as a key factor influencing honeybee social behavior. Our study is the first to highlight the propensity of S-dinotefuran to raise honeybee body temperature, which prompts honeybee to preferentially engage in trophallaxis with peers exhibiting higher body temperatures. This preference may lead honeybees to collect more dinotefuran-contaminated food in the wild, significantly accelerating dinotefuran transmission within a population. Proactive trophallaxis further amplifies the risk of neonicotinoid pesticide transmission within a population, making honeybees that have consumed S-dinotefuran particularly favored within their colonies. These findings may contribute to our understanding of the higher risk associated with neonicotinoid use compared with other pesticides.


Assuntos
Praguicidas , Abelhas , Animais , Neonicotinoides/toxicidade , Praguicidas/toxicidade , Nitrocompostos/toxicidade , Guanidinas/toxicidade
8.
RSC Adv ; 13(43): 30217-30229, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37842668

RESUMO

Poly(vinyl alcohol) (PVA)/modified porous starch (MPS) gel beads were prepared through in situ chemical cross-linking by incorporating with MPS, which was obtained by modifying porous starch (PS) with polyethyleneimine (PEI) and glutaraldehyde (GA). Addition of MPS could improve the storage modulus and the effective crosslinking density (ve) of the gel beads, and the mechanical properties were enhanced. The PVA-MPS gel beads were preserved as immobilized microbial carriers for 40 d and reactivated in wastewater. Scanning electron microscope (SEM) observations showed that the beads were highly porous and conducive for microorganism adhesion. The PVA-MPS gel beads were able to remove 97% of ammonia nitrogen and 80% of chemical oxygen demand (COD) after reactivation under all four preservation conditions. The abundance of Hydrogenophaga as denitrifying bacteria on PVA-MPS gel beads increased, with abundance of 8.44%, 5.55%, 8.90% and 9.48%, respectively. It proved that the carrier provided a partial hypoxic environment for microorganisms.

9.
Planta ; 258(5): 84, 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37736857

RESUMO

MAIN CONCLUSION: CsGolS2-1 and CsGolS2-2 are involved in the transcriptional mechanism and play an important role in the drought response of tea plants. GolS is critical for the biosynthesis of galactinol and has been suggested to contribute to drought tolerance in various plants. However, whether GolS plays a role in drought response and the underlying transcriptional mechanism of GolS genes in response to drought stress in tea plants is still unclear. In this study, we found that drought stress promotes the accumulation of galactinol in tea leaves and that the expression of CsGolS2-1 and CsGolS2-2, which encode proteins capable of catalyzing galactinol biosynthesis, is continuously and dramatically induced by drought stress. Moreover, transgenic Arabidopsis plants expressing CsGolS2-1 and CsGolS2-2 were more drought-tolerant than WT plants, as evidenced by increased cell membrane stability. In addition, the drought-responsive transcription factor CsWRKY2 has been shown to positively regulate the expression of CsGolS2-1 and CsGolS2-2 by directly binding to their promoters. Furthermore, CsVQ9 was found to interact with CsWRKY2 and promote its transcriptional function to activate CsGolS2-1 and CsGolS2-2 expression. Taken together, our findings provide insights not only into the positive role played by CsGolS2-1 and CsGolS2-2 in the drought response of tea plants but also into the transcriptional mechanisms involved.


Assuntos
Arabidopsis , Camellia sinensis , Secas , Camellia sinensis/genética , Resistência à Seca , Arabidopsis/genética , Plantas Geneticamente Modificadas , Chá
10.
ACS Omega ; 8(23): 20869-20880, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37323388

RESUMO

Incorporating metakaolin (MK) into slag to prepare alkali-activated materials can reduce shrinkage and improve the durability of alkali-activated slag (AAS). But its durability under freeze-thaw conditions is unknown. In this paper, the effects of MK content on the freeze-thaw properties of AAS were investigated from the perspective of gel composition and pore solution. The experimental results showed that the addition of MK generates a gel mixture of C-A-S-H and N-A-S-H with a cross-linked structure and decreases the content of bound water and pore water absorption. With the increase of alkali dosage, water absorption decreased to 0.28% and then increased to 0.97%, and the leaching rate of ions was Ca2+ > Al3+ > Na+ > OH-. When the alkali dosage was 8 wt % and the MK content was 30 wt %, the compressive strength loss rate of AAS was 0.58% and the mass loss rate was 0.25% after 50 freeze-thaw cycles.

11.
Database (Oxford) ; 20232023 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-37159240

RESUMO

During the production and processing of tea, harmful substances are often introduced. However, they have never been systematically integrated, and it is impossible to understand the harmful substances that may be introduced during tea production and their related relationships when searching for papers. To address these issues, a database on tea risk substances and their research relationships was constructed. These data were correlated by knowledge mapping techniques, and a Neo4j graph database centered on tea risk substance research was constructed, containing 4189 nodes and 9400 correlations (e.g. research category-PMID, risk substance category-PMID, and risk substance-PMID). This is the first knowledge-based graph database that is specifically designed for integrating and analyzing risk substances in tea and related research, containing nine main types of tea risk substances (including a comprehensive discussion of inclusion pollutants, heavy metals, pesticides, environmental pollutants, mycotoxins, microorganisms, radioactive isotopes, plant growth regulators, and others) and six types of tea research papers (including reviews, safety evaluations/risk assessments, prevention and control measures, detection methods, residual/pollution situations, and data analysis/data measurement). It is an essential reference for exploring the causes of the formation of risk substances in tea and the safety standards of tea in the future. Database URL http://trsrd.wpengxs.cn.


Assuntos
Processamento de Linguagem Natural , Reconhecimento Automatizado de Padrão , Bases de Dados Factuais , Conhecimento , Chá
12.
Sci Bull (Beijing) ; 68(10): 990-997, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37100643

RESUMO

The itinerant ferromagnetism can be induced by a van Hove singularity (VHS) with a divergent density of states at Fermi level. Utilizing the giant magnified dielectric constant εr of SrTiO3(111) substrate with cooling, here we successfully manipulated the VHS in the epitaxial monolayer (ML) 1T-VSe2 film approaching to Fermi level via the large interfacial charge transfer, and thus induced a two-dimensional (2D) itinerant ferromagnetic state below 3.3 K. Combining the direct characterization of the VHS structure via angle-resolved photoemission spectroscopy (ARPES), together with the theoretical analysis, we ascribe the manipulation of VHS to the physical origin of the itinerant ferromagnetic state in ML 1T-VSe2. Therefore, we further demonstrated that the ferromagnetic state in the 2D system can be controlled through manipulating the VHS by engineering the film thickness or replacing the substrate. Our findings clearly evidence that the VHS can serve as an effective manipulating degree of freedom for the itinerant ferromagnetic state, expanding the application potentials of 2D magnets for the next-generation information technology.


Assuntos
Asma , Doença Pulmonar Obstrutiva Crônica , Humanos , Imãs , Temperatura Baixa
13.
Small ; 19(18): e2206218, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36670078

RESUMO

By introducing different contents of Bi adatoms to the surface of monolayer graphene, the carrier concentration and their dynamics have been effectively modulated as probed directly by the time- and angle-resolved photoemission spectroscopy technique. The Bi adatoms are found to assist acoustic phonon scattering events mediated by supercollisions as the disorder effectively relaxes the momentum conservation constraint. A reduced carrier multiplication has been observed, which is related to the shrinking Fermi sea for scattering, as confirmed by time-dependent density functional theory simulation. This work gives insight into hot carrier dynamics in graphene, which is crucial for promoting the application of photoelectric devices.

14.
BMC Neurol ; 23(1): 4, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36604637

RESUMO

BACKGROUND: The majority of postoperative complications of tonsillectomy are bleeding. However, massive cerebral infarction following haemostasis is a very rare and serious complication and has rarely been reported clinically. CASE PRESENTATION: We performed a left tonsillectomy on a patient with chronic tonsillitis. After that, active bleeding was found under the tonsillar fossa, so an exploratory hypopharyngeal haemostasis was performed. However, the bleeding worsened intraoperatively, so the patient was converted to a cervical angiographic embolization. The interventional procedure was completed successfully without an ectopic embolic event. After the procedure, the patient was transferred to the intensive care unit (ICU) and was diagnosed with acute massive cerebral infarction in the left cerebral hemisphere after awakening symptoms combined with cranial computed tomography angiography (CTA) results. Symptomatic treatment such as sedation and analgesia, dehydration to lower intracranial pressure, and maintenance of respiratory and circulatory stability was then administered. After treatment, the patient's condition stabilized and he was transferred to the rehabilitation physiotherapy unit for rehabilitation. CONCLUSION: Post-tonsillectomy haemorrhage can be augmented with a carotid arteriogram to clarify whether the tonsillar fossa is at a safe distance from the posterior internal carotid artery. Furthermore, interventional haemostasis can also be performed as early as possible to reduce the incidence of complications in cases of persistent post-tonsillectomy bleeding.


Assuntos
Tonsilectomia , Tonsilite , Masculino , Humanos , Tonsilectomia/efeitos adversos , Tonsilectomia/métodos , Hemorragia Pós-Operatória/etiologia , Hemorragia Pós-Operatória/cirurgia , Tonsilite/complicações , Tonsilite/cirurgia , Complicações Pós-Operatórias/etiologia , Infarto Cerebral/complicações
15.
Pulm Pharmacol Ther ; 78: 102182, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36460268

RESUMO

BACKGROUND: Oral non-prostanoid prostacyclin receptor agonists therapies have been recommended for pulmonary arterial hypertension in many countries. OBJECTIVE: We aimed to evaluate the specific impact of non-prostanoid prostacyclin receptor agonists on pulmonary hypertension and to explore the influence of study characteristics on results. METHODS: PubMed, Embase, and ClinicalTrials.gov were systematically searched from inception to July 12, 2022. Randomized controlled trials comparing non-prostanoid prostacyclin receptor agonists administration with placebo for treating pulmonary hypertension were included. Two researchers independently selected eligible studies, assessed the bias risk and extracted related data. RevMan5.1 was used for performing the statistical analysis and the assessment of bias risk of the enrolled studies. PROSPERO registered number CRD42022304172. RESULTS: Seven trials involving 1727 patients were included. Pooled analyses indicated non-prostanoid prostacyclin receptor agonists significantly reduced clinical worsening events (risk ratio [RR], 0.63; 95% confidence interval [CI], 0.54 to 0.74), increased 6-min walk distance (mean difference [MD], 10 m; 95% CI, 3-17 m), decreased pulmonary vascular resistance (MD, -121 dyn s/cm5; 95% CI, -172 to -69 dyn s/cm5) and increased cardiac index (MD, 0.38 L/min/m2; 95% CI, 0.26-0.50 L/min/m2) compared with the control. No significant differences in all-cause mortality (RR, 0.86; 95% CI, 0.26 to 2.78), NYHA/WHO functional class (RR, 1.16; 95% CI, 0.61 to 2.18), mean pulmonary artery pressure (MD, -0.88 mmHg; 95% CI, -2.20 to 0.44 mmHg), right atrial pressure (MD, 0.66 mmHg; 95% CI, -0.59 to 1.90 mmHg) and total adverse events (RR, 1.05; 95% CI, 0.99 to 1.10) were found between non-prostanoid prostacyclin receptor agonists group and control group. CONCLUSION: Non-prostanoid prostacyclin receptor agonists treatment exerted benefits on clinical worsening, pulmonary vascular resistance, and cardiac index in pulmonary hypertension patients, without increasing the incidence of total adverse events.


Assuntos
Hipertensão Pulmonar , Humanos , Epoprostenol/efeitos adversos , Hipertensão Pulmonar Primária Familiar/tratamento farmacológico , Hipertensão Pulmonar/tratamento farmacológico , Receptores de Epoprostenol
16.
J Pept Sci ; 29(1): e3444, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35900188

RESUMO

Insect kinins are endogenous, biologically active peptides with various physiological functions. The use of insect kinins in plant protection is being evaluated by many groups. Some kinins have been chosen as lead compounds for pest control. We previously reported an insect kinin mimic IV-3 that had insecticidal activity. And by introducing a strong electron withdrawing group (-CF3 ) on the benzene ring (Phe2 ), we discovered a compound, L7 , with better activity than lead IV-3. In this work, taking L7 as the lead compound, we designed and synthesized 13 compounds to evaluate the influence of position 4 (Trp4 ) of insect kinin on insecticidal activity, by replacing the H atom on tryptophan with -CH3 and -Cl or substituting the indole ring of tryptophan with the benzene, naphthalene, pyridine, imidazole, cyclohexane, and alkyl carboxamides. The aphid bioassay results showed that the compounds M1 , M3 , and M5 were more active than the positive control, pymetrozine. Especially, replacing the side chain by an indole ring with 4-Cl substitution (M1 , LC50 = 0.0029 mmol/L) increased the aphicidal activity. The structure-activity relationships (SARs) indicated that the side chain benzene ring at this position may be important to the aphicidal activity. In addition, the toxicity prediction by Toxtree, and the toxicity experiments on Apis mellifera suggested that M1 was no toxicity risk on a non-target organism. It could be used as a selective and bee-friendly insecticide to control aphids.


Assuntos
Afídeos , Animais , Abelhas , Benzeno , Cininas , Triptofano
17.
J Agric Food Chem ; 70(41): 13391-13403, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36218024

RESUMO

Drought stress severely limits growth and causes losses in the yield of tea plants. Exogenous application of 24-epibrassinolide (EBR) positively regulates drought responses in various plants. However, whether EBR could contribute to drought resistance in tea plants and the underlying mechanisms has not been investigated. Here, we found that EBR application is beneficial for the drought tolerance of tea plants. The transcriptome results revealed that EBR could contribute to tea plant drought resistance by promoting galactinol and abscisic acid (ABA) biosynthesis gene expression. The content of galactinol was elevated by EBR and EBR-responsive CsDof1.1 positively regulated the expression of the galactinol synthase genes CsGolS2-1 and CsGolS2-2 to contribute to the accumulation of galactinol by directly binding to their promoters. Moreover, exogenous EBR was found to elevate the expression of genes related to ABA signal transduction and stomatal closure regulation, which resulted in the promotion of stomatal closure. In addition, EBR-responsive CsMYC2-2 is involved in ABA accumulation by binding to the promoters CsNCED1 and CsNCED2 to activate their expression. In summary, findings in this study provide knowledge into the transcriptional regulatory mechanism of EBR-induced drought resistance in tea plants.


Assuntos
Camellia sinensis , Secas , Ácido Abscísico/farmacologia , Ácido Abscísico/metabolismo , Dissacarídeos , Camellia sinensis/genética , Camellia sinensis/metabolismo , Chá , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico , Plantas Geneticamente Modificadas/metabolismo
18.
J Phys Chem Lett ; 13(40): 9396-9403, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36190902

RESUMO

The quantum interference patterns induced by impurities in graphene can form the (√3 × âˆš3)R30° superlattice with intervalley scattering. This superlattice can lead to the folded Dirac cone at the center of Brillouin zone by coupling two non-equivalent valleys. Using angle-resolved photoemission spectroscopy (ARPES), we report the observation of suppression of the folded Dirac cone in mono- and bilayer graphene upon potassium doping. The intervalley coupling with chiral symmetry broken can persist upon a light potassium-doped level but be ruined at the heavily doped level. Meanwhile, the folded Dirac cone can be suppressed by the renormalization of the Dirac band with potassium doping. Our results demonstrate that the suppression of the intervalley scattering pattern by potassium doping could pave the way toward the realization of novel chiraltronic devices in superlattice graphene.

19.
Molecules ; 27(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36144866

RESUMO

Neonicotinoids are important insecticides for controlling aphids in agriculture. Growing research suggested that neonicotinoid insecticides are a key factor causing the decline of global pollinator insects, such as bees. Flupyrimin (FLP) is a novel nicotinic insecticide with unique biological properties and no cross-resistance, and is safe for pollinators. Using FLP as the lead compound, a series of novel compounds were designed and synthesized by replacing the amide fragment with a sulfonamideone. Their structures were confirmed by 1H NMR, 13C NMR and HRMS spectra. Bioassay results showed that compound 2j had good insecticidal activity against Aphis glycines with an LC50 value of 20.93 mg/L. Meanwhile, compound 2j showed significantly lower acute oral and contact toxicity to Apis mellifera. In addition, compound 2j interacted well with the protein in insect acetylcholine binding protein (AChBP). The molecular docking on honeybee nicotinic acetylcholine receptor (nAChR) indicated that the sulfonamide group of compound 2j did not form a hydrogen bond with Arg173 of the ß subunit, which conforms to the reported low bee-toxicity conformation. In general, target compound 2j can be regarded as a bee-friendly insecticide candidate.


Assuntos
Afídeos , Inseticidas , Receptores Nicotínicos , Acetilcolina , Amidas , Animais , Afídeos/metabolismo , Abelhas , Proteínas de Insetos/metabolismo , Inseticidas/química , Inseticidas/toxicidade , Simulação de Acoplamento Molecular , Neonicotinoides/química , Nitrocompostos , Receptores Nicotínicos/metabolismo , Sulfonamidas
20.
Entropy (Basel) ; 24(8)2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-36010811

RESUMO

The Internet creates multidimensional and complex relationships in terms of the composition, application and mapping of social users. Most of the previous related research has focused on the single-layer topology of physical device networks but ignored the study of service access relationships and the social structure of users on the Internet. Here, we propose a composite framework to understand how the interaction between the physical devices network, business application network, and user role network affects the robustness of the entire Internet. In this paper, a multilayer network consisting of a physical device layer, business application layer and user role layer is constructed by collecting experimental network data. We characterize the disturbance process of the entire multilayer network when a physical entity device fails by designing nodal disturbance to investigate the interactions that exist between the different network layers. Meanwhile, we analyze the characteristics of the Internet-oriented multilayer network structure and propose a heuristic multilayer network topology generation algorithm based on the initial routing topology and networking pattern, which simulates the evolution process of multilayer network topology. To further analyze the robustness of this multilayer network model, we combined a total of six target node ranking indicators including random strategy, degree centrality, betweenness centrality, closeness centrality, clustering coefficient and network constraint coefficient, performed node deletion simulations in the experimental network, and analyzed the impact of component types and interactions on the robustness of the overall multilayer network based on the maximum component change in the network. These results provide new insights into the operational processes of the Internet from a multi-domain data fusion perspective, reflecting that the coupling relationships that exist between the different interaction layers are closely linked to the robustness of multilayer networks.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA