Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 198
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nano Lett ; 23(18): 8515-8523, 2023 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-37669534

RESUMO

Lithium (Li) metal is a promising anode material for high-energy-density Li batteries due to its high specific capacity. However, the uneven deposition of Li metal causes significant volume expansion and safety concerns. Here, we investigate the impact of a gradient-infused Li-metal anode using silver (Ag)-decorated carbonized cellulose fibers (Ag@CC) as a three-dimensional (3D) current collector. The loading level of the gradient-infused Li-metal anode is controlled by the thermal infusion time of molten Li. In particular, a 5 s infusion time in the Ag@CC current collector creates an appropriate space with a lithiophilic surface, resulting in improved cycling stability and a reduced volume expansion rate. Moreover, integrating a 5 s Ag@CC anode with a high-capacity cathode demonstrates superior electrochemical performance with minimal volume expansion. This suggests that a gradient-infused Li-metal anode using Ag@CC as a 3D current collector represents a novel design strategy for Li-metal-based high-capacity Li-ion batteries.

2.
Sensors (Basel) ; 23(7)2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-37050613

RESUMO

For in-vehicle network communication, the controller area network (CAN) broadcasts to all connected nodes without address validation. Therefore, it is highly vulnerable to all sorts of attack scenarios. This research proposes a novel intrusion detection system (IDS) for CAN to identify in-vehicle network anomalies. The statistical characteristics of attacks provide valuable information about the inherent intrusion patterns and behaviors. We employed two real-world attack scenarios from publicly available datasets to record a real-time response against intrusions with increased precision for in-vehicle network environments. Our proposed IDS can exploit malicious patterns by calculating thresholds and using the statistical properties of attacks, making attack detection more efficient. The optimized threshold value is calculated using brute-force optimization for various window sizes to minimize the total error. The reference values of normality require a few legitimate data frames for effective intrusion detection. The experimental findings validate that our suggested method can efficiently detect fuzzy, merge, and denial-of-service (DoS) attacks with low false-positive rates. It is also demonstrated that the total error decreases with an increasing attack rate for varying window sizes. The results indicate that our proposed IDS minimizes the misclassification rate and is hence better suited for in-vehicle networks.

3.
Int J Mol Sci ; 24(18)2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37762302

RESUMO

Fenugreek is a widely used herbal medicine as a complementary therapy for diabetes mellitus. Lots of clinical trials have proved its beneficial effect on glycemic control parameters and lipid profiles. Thus, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of fenugreek as a treatment for type 2 diabetes mellitus. We searched PubMed, Embase, Cochrane, China Knowledge Resource Integrated Database (CNKI), Korean studies Information Service System (KISS), Research Information Sharing Service (RISS), and ScienceON to select RCTs which used fenugreek targeting hyperglycemia with a control group. We used either a random effect model or a fixed model in a meta-analysis of Fasting blood glucose (FBG), 2 h plasma glucose during a 75 g oral glucose tolerance test (OGTT) (2-hPG), homeostatic model assessment for insulin resistance (HOMA-IR), glycosylated hemoglobin (HbA1c)/total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL-C), low density lipoprotein (LDL-C), body mass index (BMI). After screening, a total of 10 studies (706 participants) remained. Fenugreek significantly reduced FBG, 2-hPG, and HbA1c, but it did not significantly decrease HOMA-IR. Moreover, it significantly improved TC, TG, and HDL-C, while there were no significant differences in LDL-C and BMI. Hepatic or renal toxicity was not observed, and there were no severe adverse events associated with fenugreek despite mild gastrointestinal side effects in some studies. In conclusion, fenugreek improves overall glycemic control parameters and lipid profile safely.

4.
Lab Invest ; 102(4): 352-362, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34789838

RESUMO

Programmed death-ligand 1 (PD-L1) is constitutively expressed by hypoxia-inducible factor 2α (HIF2α). It can be induced by interferon gamma (IFNγ) signaling in clear cell renal cell carcinoma (ccRCC). Clinical trials of metastatic ccRCCs have suggested that a canonical IFNγ signature is a better biomarker for therapeutic response to immune checkpoint inhibitors (ICIs) than PD-L1 expression levels in tumor cells. To understand the therapeutic response to ICIs according to PD-L1 expression levels, we analyzed transcriptional regulation of the PD-L1 promoter by HIF2α and IFNγ-inducible interferon regulatory factor-1 (IRF-1) in ccRCC cells. Here, we present two ccRCC cell models showing differential PD-L1 expression levels in response to IFNγ and hypoxia. Analysis of The Cancer Genome Atlas RNA-sequencing data revealed that PD-L1 expression correlated with JAK2 and STAT1 expression of the canonical IFNγ signature in ccRCC tissues. Upon IFNγ stimulation, PD-L1 was induced by sequential activation of JAK2/STAT1/IRF-1 signaling in both WT- and Mut- VHL ccRCC cells. IFNγ activated the IRF-1α site of the PD-L1 promoter. The IFNγ-mediated increase of PD-L1 expression in Mut-VHL cells was 4.8-fold greater than that in WT-VHL cells. Under normoxia condition, PD-L1 expression in Mut-VHL cells was significantly higher than that in WT-VHL cells due to high basal HIF2α expression. Under hypoxia condition, PD-L1 expression in WT-VHL cells was induced up to 1.8-fold through activation of hypoxia-response elements 2 and 3. In contrast, although PD-L1 in Mut-VHL cells was already highly expressed in the basal state through activation of hypoxia-response elements 2, 3, and 4, it was no longer induced by hypoxia. In conclusion, Mut-VHL ccRCC cells displayed higher PD-L1 expression due to high basal HIF2α expression and a stronger response to IFNγ stimulation than WT-VHL cells. The fact that HIF2α antagonists can potentially reduce PD-L1 expression levels should be considered in ICI combination therapy.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Hipóxia , Interferon gama/metabolismo , Neoplasias Renais/metabolismo , Masculino , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo
5.
Am J Pathol ; 191(12): 2219-2230, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34428424

RESUMO

Transdifferentiation (or activation) of hepatic stellate cells (HSCs) to myofibroblasts is a key event in liver fibrosis. Activated HSCs in the tumor microenvironment reportedly promote tumor progression. This study analyzed the effect of an inhibitor of HSC activation, retinol-binding protein-albumin domain III fusion protein (R-III), on protumorigenic functions of HSCs. Although conditioned medium collected from activated HSCs enhanced the migration, invasion, and proliferation of the hepatocellular carcinoma cell line Hepa-1c1c7, this effect was not observed in Hepa-1c1c7 cells treated with conditioned medium from R-III-exposed HSCs. In a subcutaneous tumor model, larger tumors with increased vascular density were formed in mice transplanted with Hepa-1c1c7+HSC than in mice transplanted with Hepa-1c1c7 cells alone. Intriguingly, when Hepa-1c1c7+HSC-transplanted mice were injected intravenously with R-III, a reduction in vascular density and extended tumor necrosis were observed. In an orthotopic tumor model, co-transplantation of HSCs enhanced tumor growth, angiogenesis, and regional metastasis accompanied by increased peritumoral lymphatic vessel density, which was abolished by R-III. In vitro study showed that R-III treatment affected the synthesis of pro-angiogenic and anti-angiogenic factors in activated HSCs, which might be the potential mechanism underlying the R-III effect. These findings suggest that the inhibition of HSC activation abrogates HSC-induced tumor angiogenesis and growth, which represents an attractive therapeutic strategy.


Assuntos
Carcinoma Hepatocelular/patologia , Células Estreladas do Fígado/efeitos dos fármacos , Neoplasias Hepáticas/patologia , Proteínas Recombinantes de Fusão/farmacologia , Albuminas/química , Albuminas/farmacologia , Albuminas/uso terapêutico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/terapia , Transformação Celular Neoplásica/efeitos dos fármacos , Células Cultivadas , Regulação para Baixo/efeitos dos fármacos , Feminino , Células Estreladas do Fígado/fisiologia , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/terapia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neovascularização Patológica/genética , Neovascularização Patológica/prevenção & controle , Domínios e Motivos de Interação entre Proteínas/fisiologia , Proteínas Recombinantes de Fusão/uso terapêutico , Proteínas de Ligação ao Retinol/farmacologia , Proteínas de Ligação ao Retinol/uso terapêutico , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Appl Opt ; 60(19): D73-D82, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34263829

RESUMO

Large diameter, high-harmonic diffractive lenses could find applications in future space telescopes. Residual chromatic aberrations from these lenses can cause significant blurring. Solutions to reduce chromatic dispersion and other aberrations to diffraction-limited performance are discussed. A design example based on a 240-mm-diameter, 1-m focal length multi-order diffractive engineered lens operating over the astronomical R-Band (589-727 nm) is presented. The design example uses a relay subsystem with four times smaller diameter than the primary. This color corrector includes both refractive and diffractive optical elements and reduces the longitudinal chromatic aberrations by more than a factor of 30 compared to the primary lens alone, while maintaining the effective focal length and numerical aperture of the system.

7.
Acta Virol ; 65(2): 232-236, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34130474

RESUMO

Feline calicivirus (FCV) is a common cause of upper respiratory tract disease in cats. In this study, the complete genome sequence of FCV 14Q315, which was detected from a dead domestic cat with a hemorrhagic-like disease, was analyzed to identify the genetic characteristics. The FCV 14Q315 genome was 7,684 bp. Phylogenetic analyses based on the ORF1, ORF2, and ORF3 sequences indicated that FCV 14Q315 is more closely related to FCV 15D022 than to other FCV strains. ORF1 of FCV 14Q315 shared high sequence similarity with ORF1 of FCVs 15D022 and UTCVM-H1. We further evaluated genetic recombination in ORF1 of FCV 14Q315 and detected intergenic recombination between p30 and the ORF1/ORF2 junction with high significance. Particularly, the non-recombination region in ORF1 of FCV 14Q315 showed high sequence similarity with FCVs GX2019, CH-JL2, and 15D022. The recombination region in ORF1 of FCV 14Q315 showed the highest similarity with FCV UTCVM-H1, which is associated with a hemorrhagic-like disease. The results suggest that the UTCVM-H1-like FCV was introduced into the Republic of Korea and presumably recombined with Korean FCVs by occasional mixed infections. In addition, the Korean FCV strains were located in several phylogenetic clusters with marked genetic diversity in the ORF2 region. These results imply that Korean FCVs possess high genetic diversity owing to mutations and recombination. Furthermore, it is possible that certain FCVs caused cyclical infections in the Korean cat population based on a phylogenetic analysis of FCVs isolated at different time points. Keywords: calicivirus; virulent systemic feline calicivirus; recombination; hemorrhagic-like disease.


Assuntos
Infecções por Caliciviridae , Calicivirus Felino , Animais , Infecções por Caliciviridae/veterinária , Calicivirus Felino/genética , Gatos , Humanos , Filogenia , Recombinação Genética , República da Coreia
8.
Appl Opt ; 59(1): 28-37, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32225273

RESUMO

We present an optical architecture for a scanning lidar in which a digital micromirror device (DMD) is placed at an intermediate image plane in a receiver to decouple the trade-offs between scan angle, scan speed, and aperture size of the lidar's transmitter and receiver. In the architecture, the transmitter with a galvo mirror and the receiver with a DMD scan the horizontal and vertical fields of view, respectively, to enable an increased field of view of 50°, centimeter transmitter beam diameter, and video frame rate range finding captures. We present our optimized system and discuss the adjustable parameter trade-offs.

9.
Sensors (Basel) ; 20(15)2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32752216

RESUMO

There has been strong demand for the development of an accurate but simple method to assess the freshness of food. In this study, we demonstrated a system to determine food freshness by analyzing the spectral response from a portable visible/near-infrared (VIS/NIR) spectrometer using the Convolutional Neural Network (CNN)-based machine learning algorithm. Spectral response data from salmon, tuna, and beef incubated at 25 °C were obtained every minute for 30 h and then categorized into three states of "fresh", "likely spoiled", and "spoiled" based on time and pH. Using the obtained spectral data, a CNN-based machine learning algorithm was built to evaluate the freshness of experimental objects. In addition, a CNN-based machine learning algorithm with a shift-invariant feature can minimize the effect of the variation caused using multiple devices in a real environment. The accuracy of the obtained machine learning model based on the spectral data in predicting the freshness was approximately 85% for salmon, 88% for tuna, and 92% for beef. Therefore, our study demonstrates the practicality of a portable spectrometer in food freshness assessment.


Assuntos
Carne Vermelha , Salmão , Atum , Algoritmos , Animais , Bovinos , Redes Neurais de Computação , Alimentos Marinhos
10.
Nano Lett ; 19(3): 1504-1511, 2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30485114

RESUMO

Metallic lithium (Li) and sodium (Na) anodes have received great attention as ideal anodes to meet the needs for high energy density batteries due to their highest theoretical capacities. Although many approaches have successfully improved the performances of Li or Na metal anodes, many of these methods are difficult to scale up and thus cannot be applied in the production of batteries in practice. In this work, we introduce nanocrevasses in a carbon fiber scaffold which can facilitate the penetration of molten alkali metal into a carbon scaffold by enhancing its wettability for Li/Na metal. The resulting alkali metal/carbon composites exhibit stable long-term cycling over hundreds of cycles. The facile synthetic method is enabled for scalable production using recycled metal waste. Thus, the addition of nanocrevasses to carbon fiber as a scaffold for alkali metals can generate environmentally friendly and cost-effective composites for practical electrode applications.

11.
Molecules ; 25(23)2020 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-33260419

RESUMO

Inulae Flos, the flower of Inula britannica L., is used as a dietary supplement, beverage, and medicine in East Asia. In this study, we evaluated the gastroprotective effects of Inulae Flos extract (IFE) against gastric mucosal lesions induced by hydrochloric acid (HCl)/ethanol in rats and explored its potential mechanisms by measuring antioxidant enzyme activity, mucus secretion, and prostaglandin E2 (PGE2) levels. Pretreatment with IFE at doses of 100 and 300 mg/kg significantly inhibited gastric lesions in HCl/ethanol-treated rats. IFE increased the activities of superoxide dismutase and catalase and the levels of glutathione and PGE2 in gastric tissues. The administration of IFE also significantly increased the gastric wall mucus contents in HCl/ethanol-induced gastric lesions. These findings suggest that IFE has gastroprotective effects against HCl/ethanol-induced gastric lesions and exerts these effects through increased antioxidant levels and gastric mucus secretion. Inulae Flos may be a promising agent for the prevention and treatment of gastritis and gastric ulcers.


Assuntos
Flores/química , Inula/química , Extratos Vegetais/farmacologia , Substâncias Protetoras/farmacologia , Úlcera Gástrica/tratamento farmacológico , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Dinoprostona/metabolismo , Modelos Animais de Doenças , Etanol/toxicidade , Suco Gástrico/efeitos dos fármacos , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/patologia , Glutationa Peroxidase/metabolismo , Ácido Clorídrico/toxicidade , Masculino , Malondialdeído/metabolismo , Muco/metabolismo , Extratos Vegetais/administração & dosagem , Substâncias Protetoras/administração & dosagem , Ratos Sprague-Dawley , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/patologia , Superóxido Dismutase/metabolismo
12.
Entropy (Basel) ; 22(2)2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33285960

RESUMO

In this paper, we propose an intrusion detection system based on the estimation of the Rényi entropy with multiple orders. The Rényi entropy is a generalized notion of entropy that includes the Shannon entropy and the min-entropy as special cases. In 2018, Kim proposed an efficient estimation method for the Rényi entropy with an arbitrary real order α . In this work, we utilize this method to construct a multiple order, Rényi entropy based intrusion detection system (IDS) for vehicular systems with various network connections. The proposed method estimates the Rényi entropies simultaneously with three distinct orders, two, three, and four, based on the controller area network (CAN)-IDs of consecutively generated frames. The collected frames are split into blocks with a fixed number of frames, and the entropies are evaluated based on these blocks. For a more accurate estimation against each type of attack, we also propose a retrospective sliding window method for decision of attacks based on the estimated entropies. For fair comparison, we utilized the CAN-ID attack data set generated by a research team from Korea University. Our results show that the proposed method can show the false negative and positive errors of less than 1% simultaneously.

13.
Virus Genes ; 55(4): 545-549, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31076983

RESUMO

Bats have been widely known as natural reservoir hosts of zoonotic diseases, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) caused by coronaviruses (CoVs). In the present study, we investigated the whole genomic sequence of a SARS-like bat CoV (16BO133) and found it to be 29,075 nt in length with a 40.9% G+C content. Phylogenetic analysis using amino acid sequences of the ORF 1ab and the spike gene showed that the bat coronavirus strain 16BO133 was grouped with the Beta-CoV lineage B and was closely related to the JTMC15 strain isolated from Rhinolophus ferrumequinum in China. However, 16BO133 was distinctly located in the phylogenetic topology of the human SARS CoV strain (Tor2). Interestingly, 16BO133 showed complete elimination of ORF8 regions induced by a frame shift of the stop codon in ORF7b. The lowest amino acid identity of 16BO133 was identified at the spike region among various ORFs. The spike region of 16BO133 showed 84.7% and 75.2% amino acid identity with Rf1 (SARS-like bat CoV) and Tor2 (human SARS CoV), respectively. In addition, the S gene of 16BO133 was found to contain the amino acid substitution of two critical residues (N479S and T487 V) associated with human infection. In conclusion, we firstly carried out whole genome characterization of the SARS-like bat coronavirus discovered in the Republic of Korea; however, it presumably has no human infectivity. However, continuous surveillance and genomic characterization of coronaviruses from bats are necessary due to potential risks of human infection induced by genetic mutation.


Assuntos
Betacoronavirus/isolamento & purificação , Quirópteros/virologia , Genoma Viral , Animais , Betacoronavirus/classificação , Betacoronavirus/genética , Humanos , Tipagem Molecular , Filogenia , República da Coreia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Análise de Sequência de Proteína , Especificidade da Espécie , Sequenciamento Completo do Genoma
14.
Int J Mol Sci ; 20(5)2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30871109

RESUMO

Eleutherococcus extract mixture (EEM) is an herbal mixture of dried stem of Eleutherococcus sessiliflorus and germinated barley, which has been highly effective, in previous screening and among the traditional medicines to tonify innate qi and acquired qi, respectively. In this study, we investigate the effects of EEM on endochondral bone formation. Female adolescent rats were given EEM, growth hormone or vehicle for 10 days. Tetracycline was intraperitoneally injected to light the fluorescent band 72 h before sacrifice to determine endochondral bone formation. In order to evaluate endocrine or paracrine/autocrine mechanisms, expressions of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3), or bone morphogenetic protein 2 (BMP2) were evaluated after EEM administration in liver or growth plate (GP). EEM oral administration significantly increased endochondral bone formation and proliferative and hypertrophic zonal heights of tibial GP. EEM also upregulated hepatic IGF1 and IGFBP3 mRNA expressions, and IGF1 and BMP2 expressions in GP. Taken together, EEM increases endochondral bone formation through stimulating proliferation and hypertrophy with upregulation of hepatic IGF1 and IGFBP3 expressions. Considering immunohistochemical studies, the effect of EEM may be due to increased local IGF1 and BMP2 expression in GP, which may be considered growth hormone (GH)-dependent endocrine and autocrine/paracrine pathways.


Assuntos
Desenvolvimento Ósseo/efeitos dos fármacos , Condrócitos/efeitos dos fármacos , Eleutherococcus/química , Osteogênese/efeitos dos fármacos , Extratos Vegetais/farmacologia , Tíbia/efeitos dos fármacos , Animais , Proteína Morfogenética Óssea 2/metabolismo , Proliferação de Células/efeitos dos fármacos , Condrócitos/metabolismo , Feminino , Hormônio do Crescimento/metabolismo , Lâmina de Crescimento/efeitos dos fármacos , Lâmina de Crescimento/metabolismo , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Tíbia/metabolismo
15.
Entropy (Basel) ; 21(2)2019 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33266927

RESUMO

A new attack algorithm is proposed for a secure key generation and management method introduced by Yang and Wu. It was previously claimed that the key generation method of Yang and Wu using a keystore seed was information-theoretically secure and could solve the long-term key storage problem in cloud systems, thanks to the huge number of secure keys that the keystone seed can generate. Their key generation method, however, is considered to be broken if an attacker can recover the keystore seed. The proposed attack algorithm in this paper reconstructs the keystore seed of the Yang-Wu key generation method from a small number of collected keys. For example, when t = 5 and l = 2 7 , it was previously claimed that more than 2 53 secure keys could be generated, but the proposed attack algorithm can reconstruct the keystone seed based on only 84 collected keys. Hence, the Yang-Wu key generation method is not information-theoretically secure when the attacker can gather multiple keys and a critical amount of information about the keystone seed is leaked.

16.
Arch Virol ; 163(1): 223-227, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29038866

RESUMO

A novel avian paramyxovirus (APMV), Cheonsu1510, was isolated from wild bird feces in South Korea and serologically and genetically characterized. In hemagglutination inhibition tests, antiserum against Cheonsu1510 showed low reactivity with other APMVs and vice versa. The complete genome of Cheonsu1510 comprised 15,408 nucleotides, contained six open reading frames (3'-N-P-M-F-HN-L-5'), and showed low sequence identity to other APMVs (< 63%) and a unique genomic composition. Phylogenetic analysis revealed that Cheonsu1510 was related to but distinct from APMV-1, -9, and -15. These results suggest that Cheonsu1510 represents a new APMV serotype, APMV-17.


Assuntos
Animais Selvagens , Infecções por Avulavirus/virologia , Avulavirus/genética , Doenças das Aves/virologia , Genoma Viral , Animais , Infecções por Avulavirus/epidemiologia , Sequência de Bases , Doenças das Aves/epidemiologia , Fezes/virologia , Filogenia , República da Coreia
17.
Entropy (Basel) ; 20(9)2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-33265746

RESUMO

Since the entropy is a popular randomness measure, there are many studies for the estimation of entropies for given random samples. In this paper, we propose an estimation method of the Rényi entropy of order α . Since the Rényi entropy of order α is a generalized entropy measure including the Shannon entropy as a special case, the proposed estimation method for Rényi entropy can detect any significant deviation of an ergodic stationary random source's output. It is shown that the expected test value of the proposed scheme is equivalent to the Rényi entropy of order α . After deriving a general representation of parameters of the proposed estimator, we discuss on the particular orders of Rényi entropy such as α → 1 , α = 1 / 2 , and α = 2 . Because the Rényi entropy of order 2 is the most popular one, we present an iterative estimation method for the application with stringent resource restrictions.

18.
Angew Chem Int Ed Engl ; 57(19): 5335-5339, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29516600

RESUMO

A strategy is described to increase charge storage in a dual electrolyte Na-ion battery (DESIB) by combining the redox chemistry of the electrolyte with a Na+ ion de-insertion/insertion cathode. Conventional electrolytes do not contribute to charge storage in battery systems, but redox-active electrolytes augment this property via charge transfer reactions at the electrode-electrolyte interface. The capacity of the cathode combined with that provided by the electrolyte redox reaction thus increases overall charge storage. An aqueous sodium hexacyanoferrate (Na4 Fe(CN)6 ) solution is employed as the redox-active electrolyte (Na-FC) and sodium nickel Prussian blue (Nax -NiBP) as the Na+ ion insertion/de-insertion cathode. The capacity of DESIB with Na-FC electrolyte is twice that of a battery using a conventional (Na2 SO4 ) electrolyte. The use of redox-active electrolytes in batteries of any kind is an efficient and scalable approach to develop advanced high-energy-density storage systems.

19.
Virol J ; 14(1): 60, 2017 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-28327168

RESUMO

BACKGROUND: On November 20, 2016 two novel strains of H5N6 highly pathogenic avian influenza virus (HPAIVs) were isolated from three whooper swans (Cygnus cygnus) at Gangjin Bay in South Jeolla province, South Korea. Identification of HPAIVs in wild birds is significant as there is a potential risk of transmission of these viruses to poultry and humans. RESULTS: Phylogenetic analysis revealed that Gangjin H5N6 viruses classified into Asian H5 clade 2.3.4.4 lineage and were distinguishable from H5N8 and H5N1 HPAIVs previously isolated in Korea. With the exception of the polymerase acidic (PA) gene, the viruses were most closely related to A/duck/Guangdong/01.01SZSGXJK005-Y/2016 (H5N6) (98.90 ~ 99.74%). The PA genes of the two novel Gangjin H5N6 viruses were most closely related to AIV isolates previously characterized from Korea, A/hooded crane/Korea/1176/2016 (H1N1) (99.16%) and A/environment/Korea/W133/2006 (H7N7) (98.65%). The lack of more recent viruses to A/environment/Korea/W133/2006 (H7N7) indicates the need for analysis of recent wild bird AIVs isolated in Korea because they might provide further clues as to the origin of these novel reassortant H5N6 viruses. CONCLUSIONS: Although research on the origins and epidemiology of these infections is ongoing, the most likely route of infection for the whooper swans was through direct or indirect contact with reassortant viruses shed by migratory wild birds in Korea. As H5N6 HPAIVs can potentially be transmitted to poultry and humans, continuous monitoring of AIVs among wild birds will help to mitigate this risk.


Assuntos
Anseriformes/virologia , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/virologia , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Animais , Análise por Conglomerados , Vírus da Influenza A/classificação , Filogenia , Vírus Reordenados/classificação , República da Coreia
20.
Arch Virol ; 162(12): 3887-3891, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28900762

RESUMO

We report the identification of a novel reassortant clade 2.3.4.4 H5N8 virus from a dead grey heron in Korea in 2017. Outbreaks of clade 2.3.4.4 H5 HPAIVs have been reported worldwide, and they have evolved into multiple genotypes among wild birds. Phylogenetic analysis indicated that this virus likely originated from Qinghai Lake and Western Siberia and further evolved through reassortment with Eurasian LPAI during the 2016 fall migration of wild birds. Enhanced surveillance and comparative genetic analysis will help to monitor the further evolution and dissemination of clade 2.3.4.4 HPAIVs.


Assuntos
Vírus da Influenza A Subtipo H5N8/classificação , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Influenza Aviária/virologia , Vírus Reordenados/classificação , Vírus Reordenados/isolamento & purificação , Animais , Aves , Evolução Molecular , Vírus da Influenza A Subtipo H5N8/genética , Filogenia , Vírus Reordenados/genética , República da Coreia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA