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1.
Nano Lett ; 24(10): 3213-3220, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38426819

RESUMO

Rational design of well-defined active sites is crucial for promoting sluggish oxygen reduction reactions. Herein, leveraging the surfactant-oriented and solvent-ligand effects, we develop a facile self-assembly strategy to construct a core-shell catalyst comprising a high-index Pt shell encapsulating a PtCu3 intermetallic core with efficient oxygen-reduction performance. Without undergoing a high-temperature route, the ordered PtCu3 is directly fabricated through the accelerated reduction of Cu2+, followed by the deposition of the remaining Pt precursor onto its surface, forming high-index steps oriented by the steric hindrance of surfactant. This approach results in a high half-wave potential of 0.911 V versus reversible hydrogen electrode, with negligible deactivation even after 15000-cycle operation. Operando spectroscopies identify that this core-shell catalyst facilitates the conversion of oxygen-involving intermediates and ensures antidissolution ability. Theoretical investigations rationalize that this improvement is attributed to reinforced electronic interactions around high-index Pt, stabilizing the binding strength of rate-determining OHads species.

2.
Arch Toxicol ; 98(1): 75-94, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37934210

RESUMO

Ferroptosis is a newly discovered form of regulatory cell death characterized by excessive iron-dependent lipid peroxidation. In the past decade, significant breakthroughs have been made in comprehending the features and regulatory mechanisms of ferroptosis, and it has been confirmed that ferroptosis plays a pivotal role in the pathophysiological processes of various diseases, including tumors, inflammation, neurodegenerative diseases, and infectious diseases. The pancreas, which is the second largest digestive gland in the human body and has both endocrine and exocrine functions, is a vital organ for controlling digestion and metabolism. In recent years, numerous studies have confirmed that ferroptosis is closely related to pancreatic diseases, which is attributed to abnormal iron accumulation, as an essential biochemical feature of ferroptosis, is often present in the pathological processes of various pancreatic exocrine and endocrine diseases and the vulnerability of the pancreas to oxidative stress stimulation and damage. Therefore, comprehending the regulatory mechanism of ferroptosis in pancreatic diseases may provide valuable new insights into treatment strategies. In this review, we first summarize the hallmark features of ferroptosis and then analyze the exact mechanisms by which ferroptosis is precisely regulated at multiple levels and links, including iron metabolism, lipid metabolism, the GPX4-mediated ferroptosis defense system, the GPX4-independent ferroptosis defense system, and the regulation of autophagy on ferroptosis. Finally, we discuss the role of ferroptosis in the occurrence and development of pancreatic diseases and summarize the feasibility and limitations of ferroptosis as a therapeutic target for pancreatic diseases.


Assuntos
Ferroptose , Pancreatopatias , Humanos , Autofagia , Morte Celular , Ferro
3.
Opt Express ; 31(3): 3698-3707, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36785356

RESUMO

Acoustic graphene plasmons (AGPs) in a graphene-dielectric-metal structure possess extreme field localization and low loss, which have promising applications in strong photon-matter interaction and integrated photonic devices. Here, we propose two kinds of one-dimensional crystals supporting propagating AGPs with different topological properties, which is confirmed by the Zak phase calculations and the electric field symmetry analysis. Moreover, by combining these two plasmonic crystals to form a superlattice system, the super-modes exist because of the coupling between isolated topological interface states. A flat-like dispersion of super-modes is observed by designing the superlattice. These results should find applications in optical sensing and integrating photonic devices with plasmonic crystals.

4.
BMC Womens Health ; 23(1): 91, 2023 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-36882777

RESUMO

BACKGROUND: Breast cancer is a serious threat to female health, and its incidence varies with education level (EL). In the present study, the association between EL and the risk of developing female breast cancer was investigated. METHODS: From May 2006 to December 2007, 20,400 observation subjects in Kailuan Cohort received questionnaires and were subjected to clinical examinations for data collection on baseline population characteristics, height, weight, lifestyle and past disease history. Then, these participants were followed up with from the date of recruitment to December 31, 2019. Cox proportional risk regression models were used to analyse the association between EL and the risk of developing female breast cancer. RESULTS: The cumulative follow-up period of 20,129 observation subjects that meet the inclusion criteria of this study was 254,386.72 person-years, and the median follow-up time was 12.96 years. During the follow-up period, 279 cases of breast cancer were diagnosed. In comparison with the low EL group, the risk of developing breast cancer was significantly higher in the medium (hazard ratio [HR] (95% confidence interval [CI]) = 2.23 (1.12-4.64)] and high [HRs (95% CI) = 2.52 (1.12-5.70)] EL group. CONCLUSION: An increased risk of breast cancer was associated with a higher EL, and some certain factors, such as alcohol use and hormone therapy, may play a mediating role.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Neoplasias da Mama/epidemiologia , Estudos Prospectivos , Escolaridade , Saúde da Mulher , Consumo de Bebidas Alcoólicas/efeitos adversos , Consumo de Bebidas Alcoólicas/epidemiologia
5.
BMC Urol ; 23(1): 150, 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37736725

RESUMO

OBJECTIVE: To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing urologic cancers. METHODS: This study included 101,510 observation subjects from May 2006 to December 2007. The subjects received questionnaires and were subjected to clinical and laboratory examinations to collect data on baseline population characteristics, waist circumference (WC), blood pressure (BP), blood glucose, blood lipids, lifestyle, and past disease history. Finally, follow-up was conducted from the date of recruitment to December 31, 2019. Cox proportional hazards modelling was applied to analyze the association between MetS and its components and the risk of developing urologic cancers. RESULTS: A total of 97,975 observation subjects met the inclusion criteria. The cumulative follow-up period included 1,209,178.65 person-years, and the median follow-up time was 13.03 years. During the follow-up period, 485 cases of urologic cancers (165 cases of kidney cancer, 134 cases of prostate cancer, 158 cases of bladder cancer, and 28 cases of other urologic cancers) were diagnosed. The log-rank test results for the cumulative incidences of urologic cancer, kidney cancer, and prostate cancer indicated significant (P < 0.01) differences between the MetS and non-MetS groups (0.70% vs. 0.48%, 0.27% vs. 0.15%, and 0.22% vs. 0.13%, respectively). Compared to the non-MetS group, the risk of developing urologic [HR (95% CI) = 1.29 (1.08-1.55)], kidney [HR (95% CI) = 1.74 (1.28-2.37)], and prostate [HR (95% CI) = 1.47 (1.04-2.07)] cancers was significantly higher in the MetS group. In the MetS group, elevated BP increased the risk of developing of urologic cancer [HRs (95% CI) = 1.35 (1.10-1.66)] and kidney cancer [HR (95% CI) = 1.74 (1.21-2.51)], while central obesity increased the risk of developing prostate cancer [HR (95% CI) = 1.68 (1.18-2.40)]. CONCLUSIONS: MetS increased the risk of developing urologic, kidney, and prostate cancers but had no association with the development of bladder cancer.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Síndrome Metabólica , Neoplasias da Próstata , Neoplasias da Bexiga Urinária , Neoplasias Urológicas , Masculino , Humanos , Síndrome Metabólica/complicações , Síndrome Metabólica/epidemiologia , Estudos Prospectivos , Neoplasias Urológicas/epidemiologia , Neoplasias da Bexiga Urinária/epidemiologia , Neoplasias da Bexiga Urinária/etiologia , Neoplasias Renais/epidemiologia , Neoplasias Renais/etiologia , Neoplasias da Próstata/epidemiologia
6.
Angew Chem Int Ed Engl ; 62(13): e202217719, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36692894

RESUMO

The construction and understanding of synergy in well-defined dual-atom active sites is an available avenue to promote multistep tandem catalytic reactions. Herein, we construct a dual-hetero-atom catalyst that comprises adjacent Cu-N4 and Se-C3 active sites for efficient oxygen reduction reaction (ORR) activity. Operando X-ray absorption spectroscopy coupled with theoretical calculations provide in-depth insights into this dual-atom synergy mechanism for ORR under realistic device operation conditions. The heteroatom Se modulator can efficiently polarize the charge distribution around symmetrical Cu-N4 moieties, and serve as synergistic site to facilitate the second oxygen reduction step simultaneously, in which the key OOH*-(Cu1 -N4 ) transforms to O*-(Se1 -C2 ) intermediate on the dual-atom sites. Therefore, this designed catalyst achieves satisfied alkaline ORR activity with a half-wave potential of 0.905 V vs. RHE and a maximum power density of 206.5 mW cm-2 in Zn-air battery.

7.
Sensors (Basel) ; 22(9)2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35590856

RESUMO

Dynamic displacement plays an essential role in structural health monitoring. To overcome the shortcomings of displacement measured directly, such as installation difficulty of monitoring devices, this paper proposes a smart reconstruction method, which can realize real-time intelligent online reconstruction of structural displacement. Unlike the existing approaches, the proposed algorithm combines the improved mode superposition methods that is suitable for complex beam structures with the Kalman filtering approach using acceleration and strain data. The effectiveness of the proposed multi-rate data fusion method for dynamic displacement reconstruction is demonstrated by both numerical simulation and model vibration experiment. Parametric analysis shows that the reconstruction error is only 5% when the noise signal to noise ratio is 5 dB, illustrating that the proposed algorithm has excellent anti-noise performance. The results also indicate that both the high-frequency and low-frequency components of the dynamic displacements can be accurately reconstructed through the proposed method, which has good robustness.


Assuntos
Aceleração , Algoritmos , Simulação por Computador , Razão Sinal-Ruído
8.
PLoS Pathog ; 15(4): e1007732, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30964921

RESUMO

[This corrects the article DOI: 10.1371/journal.ppat.1007253.].

9.
PLoS Pathog ; 14(9): e1007253, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30212568

RESUMO

Shugoshin-1 (Sgo1) protects the integrity of the centromeres, and H2A phosphorylation is critical for this process. The mitotic checkpoint kinase Bub1, phosphorylates H2A and ensures fidelity of chromosome segregation and chromosome number. Oncogenic KSHV induces genetic alterations through chromosomal instability (CIN), and its essential antigen LANA regulates Bub1. We show that LANA inhibits Bub1 phosphorylation of H2A and Cdc20, important for chromosome segregation and mitotic signaling. Inhibition of H2A phosphorylation at residue T120 by LANA resulted in dislocation of Sgo1, and cohesin from the centromeres. Arrest of Cdc20 phosphorylation also rescued degradation of Securin and Cyclin B1 at mitotic exit, and interaction of H2A, and Cdc20 with Bub1 was inhibited by LANA. The N-terminal nuclear localization sequence domain of LANA was essential for LANA and Bub1 interaction, reversed LANA inhibited phosphorylation of H2A and Cdc20, and attenuated LANA-induced aneuploidy and cell proliferation. This molecular mechanism whereby KSHV-induced CIN, demonstrated that the NNLS of LANA is a promising target for development of anti-viral therapies targeting KSHV associated cancers.


Assuntos
Aneuploidia , Antígenos Virais/genética , Antígenos Virais/metabolismo , Proteínas de Ciclo Celular/metabolismo , Herpesvirus Humano 8/imunologia , Herpesvirus Humano 8/patogenicidade , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Antígenos Virais/química , Proteínas Cdc20/metabolismo , Pontos de Checagem do Ciclo Celular , Linhagem Celular , Centrômero/metabolismo , Instabilidade Cromossômica , Ciclina B1/metabolismo , Herpesvirus Humano 8/genética , Histonas/metabolismo , Humanos , Mitose , Modelos Biológicos , Sinais de Localização Nuclear/genética , Sinais de Localização Nuclear/metabolismo , Proteínas Nucleares/química , Fosforilação , Domínios e Motivos de Interação entre Proteínas , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteólise , Securina/metabolismo
10.
Nanotechnology ; 31(22): 225402, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32066134

RESUMO

Heating under low solar radiation intensity is demonstrated to facilitate the cleaning of crude oil by the hydrophobic nanocomposite adsorbents of reduced graphene oxide (RGO) melamine sponge (MS@RGO) foams. The heat generated by the irradiation reduces the viscosity of the crude oil, and consequently increases the oil-diffusion coefficient of the pores of the MS@RGO foams and speeds up the oil-sorption rate. Even under a solar radiation intensity as low as 2 kW m-2, the temperature of crude oil rapidly rises to 68 °C or higher within 10 min. It only takes 29 s to completely absorb 6 g of crude oil at 60 °C by three tiny pieces of MS@RGO foam. This work makes better use of the excellent photothermal conversion characteristics of crude oil, and its photothermal conversion mechanism under simulated solar radiation is also discussed. This methodology can be adopted to clean up viscous crude oil or extract other chemicals effectively at a large scale, and provides a complete solution for the cleanup of crude oil in the sea or on the beach for actual engineering applications.

11.
J Musculoskelet Neuronal Interact ; 20(4): 563-569, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33265085

RESUMO

OBJECTIVE: To investigate the expression of interleukin-17 (IL-17) in zoledronic acid combined with PVP technology for patients with postmenopausal osteoporotic vertebral compression fracture (OVCF) and its predictive value for relapse. METHODS: 101 OVCF patients treated in our hospital from April 2013 to January 2015 were collected as a research group and treated by zoledronic acid combined with PVP technology. 80 healthy people with physical examination were assigned to the control group. ELISA was used to detect the expression of IL-17 in serum of the two groups. Patients were followed up for 2 years. The expression of IL-17 before treatment was compared between patients with relapse and patients without relapse. The predictive value of IL-17 in relapse was drawn according to ROC curve. RESULTS: Before treatment, the expression of IL-17 in the research group increased significantly (p<0.05). After treatment, the expression of IL-17 in the research group decreased significantly (p<0.05). The level of IL-17 in patients with relapse was significantly higher than that in patients without relapse (p<0.05). CONCLUSIONS: IL-17 is highly expressed in postmenopausal patients with osteoporotic vertebral compression fracture and is expected to be a potential predictor of relapse in postmenopausal patients with OVCF.


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Interleucina-17/sangue , Fraturas por Osteoporose/terapia , Fraturas da Coluna Vertebral/terapia , Vertebroplastia/métodos , Ácido Zoledrônico/administração & dosagem , Idoso , Biomarcadores/sangue , Feminino , Fraturas por Compressão , Humanos , Infusões Intravenosas , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/terapia , Recidiva , Resultado do Tratamento
12.
PLoS Pathog ; 13(7): e1006500, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28738086

RESUMO

The latent EBV nuclear antigen 3C (EBNA3C) is required for transformation of primary human B lymphocytes. Most mature B-cell malignancies originate from malignant transformation of germinal center (GC) B-cells. The GC reaction appears to have a role in malignant transformation, in which a major player of the GC reaction is Bcl6, a key regulator of this process. We now demonstrate that EBNA3C contributes to B-cell transformation by targeted degradation of Bcl6. We show that EBNA3C can physically associate with Bcl6. Notably, EBNA3C expression leads to reduced Bcl6 protein levels in a ubiquitin-proteasome dependent manner. Further, EBNA3C inhibits the transcriptional activity of the Bcl6 promoter through interaction with the cellular protein IRF4. Bcl6 degradation induced by EBNA3C rescued the functions of the Bcl6-targeted downstream regulatory proteins Bcl2 and CCND1, which resulted in increased proliferation and G1-S transition. These data provide new insights into the function of EBNA3C in B-cell transformation during GC reaction, and raises the possibility of developing new targeted therapies against EBV-associated cancers.


Assuntos
Proliferação de Células , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/virologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Infecções por Vírus Epstein-Barr/genética , Infecções por Vírus Epstein-Barr/fisiopatologia , Antígenos Nucleares do Vírus Epstein-Barr/genética , Regulação da Expressão Gênica , Herpesvirus Humano 4/genética , Interações Hospedeiro-Patógeno , Humanos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Proteólise , Proteínas Proto-Oncogênicas c-bcl-6/genética
13.
PLoS Pathog ; 12(8): e1005844, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27548379

RESUMO

Epstein-Barr virus (EBV) is considered a ubiquitous herpesvirus with the ability to cause latent infection in humans worldwide. EBV-association is evidently linked to different types of human malignancies, mainly of epithelial and lymphoid origin. Of interest is the EBV nuclear antigen 3C (EBNA3C) which is critical for EBV-mediated immortalization. Recently, EBNA3C was shown to bind the E2F1 transcription regulator. The E2F transcription factors have crucial roles in various cellular functions, including cell cycle, DNA replication, DNA repair, cell mitosis, and cell fate. Specifically, E2F6, one of the unique E2F family members, is known to be a pRb-independent transcription repressor of E2F-target genes. In our current study, we explore the role of EBNA3C in regulating E2F6 activities. We observed that EBNA3C plays an important role in inducing E2F6 expression in LCLs. Our study also shows that EBNA3C physically interacts with E2F6 at its amino and carboxy terminal domains and they form a protein complex in human cells. In addition, EBNA3C stabilizes the E2F6 protein and is co-localized in the nucleus. We also demonstrated that both EBNA3C and E2F6 contribute to reduction in E2F1 transcriptional activity. Moreover, E2F1 forms a protein complex with EBNA3C and E2F6, and EBNA3C competes with E2F1 for E2F6 binding. E2F6 is also recruited by EBNA3C to the E2F1 promoter, which is critical for EBNA3C-mediated cell proliferation. These results demonstrate a critical role for E2F family members in EBV-induced malignancies, and provide new insights for targeting E2F transcription factors in EBV-associated cancers as potential therapeutic intervention strategies.


Assuntos
Proliferação de Células , Fator de Transcrição E2F1/metabolismo , Fator de Transcrição E2F6/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/metabolismo , Transcrição Gênica , Fator de Transcrição E2F1/genética , Fator de Transcrição E2F6/genética , Antígenos Nucleares do Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Humanos
14.
PLoS Pathog ; 12(7): e1005801, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27463802

RESUMO

Studies have suggested that Epithelial-Mesenchymal Transition (EMT) and transformation is an important step in progression to cancer. Par3 (partitioning-defective protein) is a crucial factor in regulating epithelial cell polarity. However, the mechanism by which the latency associated nuclear antigen (LANA) encoded by Kaposi's Sarcoma associated herpesvirus (KSHV) regulates Par3 and EMTs markers (Epithelial-Mesenchymal Transition) during viral-mediated B-cell oncogenesis has not been fully explored. Moreover, several studies have demonstrated a crucial role for EMT markers during B-cell malignancies. In this study, we demonstrate that Par3 is significantly up-regulated in KSHV-infected primary B-cells. Further, Par3 interacted with LANA in KSHV positive and LANA expressing cells which led to translocation of Par3 from the cell periphery to a predominantly nuclear signal. Par3 knockdown led to reduced cell proliferation and increased apoptotic induction. Levels of SNAIL was elevated, and E-cadherin was reduced in the presence of LANA or Par3. Interestingly, KSHV infection in primary B-cells led to enhancement of SNAIL and down-regulation of E-cadherin in a temporal manner. Importantly, knockdown of SNAIL, a major EMT regulator, in KSHV cells resulted in reduced expression of LANA, Par3, and enhanced E-cadherin. Also, SNAIL bound to the promoter region of p21 and can regulate its activity. Further a SNAIL inhibitor diminished NF-kB signaling through upregulation of Caspase3 in KSHV positive cells in vitro. This was also supported by upregulation of SNAIL and Par3 in BC-3 transplanted NOD-SCID mice which has potential as a therapeutic target for KSHV-associated B-cell lymphomas.


Assuntos
Linfócitos B/virologia , Proteínas de Ciclo Celular/metabolismo , Transformação Celular Viral/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Infecções por Herpesviridae/metabolismo , Proteínas de Membrana/metabolismo , Fatores de Transcrição da Família Snail/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Antígenos Virais/metabolismo , Western Blotting , Feminino , Imunofluorescência , Regulação da Expressão Gênica/fisiologia , Herpesvirus Humano 8 , Humanos , Imuno-Histoquímica , Imunoprecipitação , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
15.
Bioorg Chem ; 79: 111-114, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29738969

RESUMO

A novel tetrahydrofuran derivative, trigonohowine (1), together with five known tetrahydrofuran derivatives (2-6), were isolated from the stems and leaves of Trigonostemon howii. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with the data reported in literature. Among them, trigonohowine (1) represents the first example of a new type of tetrahydrofuran derivative, possessing an unprecedented carbon skeleton containing 23 carbon atoms on the carbon skeleton and the known compouds (2-6) are rare tetrahydrofuran derivatives in the plant kingdom with various carbon skeletons. All isolated compounds were evaluated for their anti-HIV-1 activities. Compounds 1-6 showed significant anti-HIV-1 activities with EC50 ranged from 0.08 to 1.03 µM. These findings suggest that the discoveries of these tetrahydrofuran derivatives with significant anti-HIV-1 activities isolated from T. howii could be of great importance to the development of new anti-HIV agents.


Assuntos
Fármacos Anti-HIV/farmacologia , Euphorbiaceae/química , Furanos/farmacologia , HIV-1/efeitos dos fármacos , Fármacos Anti-HIV/química , Fármacos Anti-HIV/isolamento & purificação , Linhagem Celular , Furanos/química , Furanos/isolamento & purificação , Humanos , Estrutura Molecular , Folhas de Planta/química , Caules de Planta/química
16.
Sensors (Basel) ; 18(12)2018 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-30544944

RESUMO

Spectrum sensing plays an essential role in the detection of unused spectrum whole in cognitive radio networks, including cooperative spectrum sensing (CSS) and independent spectrum sensing. In cognitive radio ad hoc networks (CRAHNs), CSS enhances the sensing performance of cognitive nodes by exploring the spectrum partial homogeneity and fully utilizing the knowledge of neighboring nodes, e.g., sensing results and topological information. However, CSS may also open a door for malicious nodes, i.e., spectrum sensing data falsification (SSDF) attackers, which report fake sensing results to deteriorate the performance of CSS. Generally, the performance of CSS has an inverse relationship with the fraction of SSDF attackers. On the contrary, independent spectrum sensing is robust to SSDF attacks. Therefore, it is desirable to choose a proper sensing strategy between independent sensing and collaborative sensing for CRAHNs coexisting with various fractions of SSDF attackers. In this paper, a novel algorithm called Spectrum Sensing Strategy Selection (4S) is proposed to select better sensing strategies either in a collaborative or in an independent manner. To derive the maximum a posteriori estimation of nodes' spectrum status, we investigated the graph cut-based CSS method, through which the topological information cost function and the sensing results cost function were constructed. Moreover, the reputation value was applied to evaluate the performance of CSS and independent sensing. The reputation threshold was theoretically analyzed to minimize the probability of choosing the sensing manner with worse performance. Simulations were carried out to verify the viability and the efficiency of the proposed algorithm.

17.
Sensors (Basel) ; 18(5)2018 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-29883399

RESUMO

Pedestrian-positioning technology based on the foot-mounted micro inertial measurement unit (MIMU) plays an important role in the field of indoor navigation and has received extensive attention in recent years. However, the positioning accuracy of the inertial-based pedestrian-positioning method is rapidly reduced because of the relatively low measurement accuracy of the measurement sensor. The zero-velocity update (ZUPT) is an error correction method which was proposed to solve the cumulative error because, on a regular basis, the foot is stationary during the ordinary gait; this is intended to reduce the position error growth of the system. However, the traditional ZUPT has poor performance because the time of foot touchdown is short when the pedestrians move faster, which decreases the positioning accuracy. Considering these problems, a forward and reverse calculation method based on the adaptive zero-velocity interval adjustment for the foot-mounted MIMU location method is proposed in this paper. To solve the inaccuracy of the zero-velocity interval detector during fast pedestrian movement where the contact time of the foot on the ground is short, an adaptive zero-velocity interval detection algorithm based on fuzzy logic reasoning is presented in this paper. In addition, to improve the effectiveness of the ZUPT algorithm, forward and reverse multiple solutions are presented. Finally, with the basic principles and derivation process of this method, the MTi-G710 produced by the XSENS company is used to complete the test. The experimental results verify the correctness and applicability of the proposed method.


Assuntos
, Pedestres , Algoritmos , Lógica Fuzzy , Marcha , Humanos
18.
Small ; 13(9)2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28067991

RESUMO

The recent success of organometallic halide perovskites (OHPs) in photovoltaic devices has triggered lots of corresponding research and many perovskite analogues have been developed to look for devices with comparable performance but better stability. Upon the preparation of all inorganic halide perovskite nanocrystals (IHP NCs), research activities have soared due to their better stability, ultrahigh photoluminescence quantum yield (PL QY), and composition dependent luminescence covering the whole visible region with narrow line-width. They are expected to be promising materials for next generation lighting and display, and many other applications. Within two years, a lot of interesting results have been observed. Here, the synthesis of IHPs is reviewed, and their progresses in optoelectronic devices and optical applications, such as light-emitting diodes (LEDs), photodetectors (PDs), solar cells (SCs), and lasing, is presented. Information and recent understanding of their crystal structures and morphology modulations are addressed. Finally, a brief outlook is given, highlighting the presently main problems and their possible solutions and future development directions.

19.
J Virol ; 90(18): 8047-58, 2016 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-27356905

RESUMO

UNLABELLED: Kaposi's sarcoma-associated herpesvirus (KSHV) maintains two modes of life cycle, the latent and lytic phases. To evade the attack of the cell host's immune system, KSHV switches from the lytic to the latent phase, a phase in which only a few of viral proteins are expressed. The mechanism by which KSHV evades the attack of the immune system and establishes latency has not been fully understood. Major histocompatibility complex class II (MHC-II) molecules are key components of the immune system defense mechanism against viral infections. Here we report that HLA-DRα, a member of the MHC-II molecules, was downregulated by the replication and transcription activator (RTA) protein encoded by KSHV ORF50, an important regulator of the viral life cycle. RTA not only downregulated HLA-DRα at the protein level through direct binding and degradation through the proteasome pathway but also indirectly downregulated the protein level of HLA-DRα by enhancing the expression of MARCH8, a member of the membrane-associated RING-CH (MARCH) proteins. Our findings indicate that KSHV RTA facilitates evasion of the virus from the immune system through manipulation of HLA-DRα. IMPORTANCE: Kaposi's sarcoma-associated herpesvirus (KSHV) has a causal role in a number of human cancers, and its persistence in infected cells is controlled by the host's immune system. The mechanism by which KSHV evades an attack by the immune system has not been well understood. This work represents studies which identify a novel mechanism by which the virus can facilitate evasion of an immune system. We now show that RTA, the replication and transcription activator encoded by KSHV (ORF50), can function as an E3 ligase to degrade HLA-DRα. It can directly bind and induce degradation of HLA-DRα through the ubiquitin-proteasome degradation pathway. In addition to the direct regulation of HLA-DRα, RTA can also indirectly downregulate the level of HLA-DRα protein by upregulating transcription of MARCH8. Increased MARCH8 results in the downregulation of HLA-DRα. Furthermore, we also demonstrate that expression of HLA-DRα was impaired in KSHV de novo infection.


Assuntos
Regulação para Baixo , Cadeias alfa de HLA-DR/biossíntese , Herpesvirus Humano 8/patogenicidade , Interações Hospedeiro-Patógeno , Proteínas Imediatamente Precoces/metabolismo , Evasão da Resposta Imune , Transativadores/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Linhagem Celular , Humanos
20.
J Virol ; 89(20): 10206-18, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26223641

RESUMO

UNLABELLED: Latent DNA replication of Kaposi's sarcoma-associated herpesvirus (KSHV) initiates at the terminal repeat (TR) element and requires trans-acting elements, both viral and cellular, such as ORCs, MCMs, and latency-associated nuclear antigen (LANA). However, how cellular proteins are recruited to the viral genome is not very clear. Here, we demonstrated that the host cellular protein, Bub1, is involved in KSHV latent DNA replication. We show that Bub1 constitutively interacts with proliferating cell nuclear antigen (PCNA) via a highly conserved PIP box motif within the kinase domain. Furthermore, we demonstrated that Bub1 can form a complex with LANA and PCNA in KSHV-positive cells. This strongly indicated that Bub1 serves as a scaffold or molecular bridge between LANA and PCNA. LANA recruited PCNA to the KSHV genome via Bub1 to initiate viral replication in S phase and interacted with PCNA to promote its monoubiquitination in response to UV-induced damage for translesion DNA synthesis. This resulted in increased survival of KSHV-infected cells. IMPORTANCE: During latency in KSHV-infected cells, the viral episomal DNA replicates once each cell cycle. KSHV does not express DNA replication proteins during latency. Instead, KSHV LANA recruits the host cell DNA replication machinery to the replication origin. However, the mechanism by which LANA mediates replication is uncertain. Here, we show that LANA is able to form a complex with PCNA, a critical protein for viral DNA replication. Furthermore, our findings suggest that Bub1, a spindle checkpoint protein, serves as a scaffold or molecular bridge between LANA and PCNA. Our data further support a role for Bub1 and LANA in PCNA-mediated cellular DNA replication processes as well as monoubiquitination of PCNA in response to UV damage. These data reveal a therapeutic target for inhibition of KSHV persistence in malignant cells.


Assuntos
Antígenos Virais/genética , DNA Viral/genética , Genoma Viral , Herpesvirus Humano 8/genética , Proteínas Nucleares/genética , Osteoblastos/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Proteínas Serina-Treonina Quinases/genética , Sequência de Aminoácidos , Antígenos Virais/metabolismo , Linhagem Celular , Sobrevivência Celular , Replicação do DNA , DNA Viral/metabolismo , Regulação da Expressão Gênica , Herpesvirus Humano 8/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Osteoblastos/virologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fase S , Transdução de Sinais , Sequências Repetidas Terminais , Ubiquitinação , Latência Viral , Replicação Viral
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