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1.
BMC Genomics ; 25(1): 262, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38459433

RESUMO

Plague, as an ancient zoonotic disease caused by Yersinia pestis, has brought great disasters. The natural plague focus of Marmota himalayana in the Qinghai-Tibet Plateau is the largest, which has been constantly active and the leading source of human plague in China for decades. Understanding the population genetics of M. himalayana and relating that information to the biogeographic distribution of Yersinia pestis and plague outbreaks are greatly beneficial for the knowledge of plague spillover and arecrucial for pandemic prevention. In the present research, we assessed the population genetics of M. himalayana. We carried out a comparative study of plague outbreaks and the population genetics of M. himalayana on the Qinghai-Tibet Plateau. We found that M. himalayana populations are divided into two main clusters located in the south and north of the Qinghai-Tibet Plateau. Fourteen DFR genomovars of Y. pestis were found and exhibited a significant region-specific distribution. Additionally, the increased genetic diversity of plague hosts is positively associated with human plague outbreaks. This insight gained can improve our understanding of biodiversity for pathogen spillover and provide municipally directed targets for One Health surveillance development, which will be an informative next step toward increased monitoring of M. himalayana dynamics.


Assuntos
Marmota , Yersinia pestis , Animais , Humanos , Tibet/epidemiologia , China/epidemiologia , Surtos de Doenças , Yersinia pestis/genética , Variação Genética
2.
Emerg Infect Dis ; 30(13): S21-S27, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38561638

RESUMO

Institution-level wastewater-based surveillance was implemented during the COVID-19 pandemic, including in carceral facilities. We examined the relationship between COVID-19 diagnostic test results of residents in a jail in Atlanta, Georgia, USA (average population ≈2,700), and quantitative reverse transcription PCR signal for SARS-CoV-2 in weekly wastewater samples collected during October 2021‒May 2022. The jail offered residents rapid antigen testing at entry and periodic mass screenings by reverse transcription PCR of self-collected nasal swab specimens. We aggregated individual test data, calculated the Spearman correlation coefficient, and performed logistic regression to examine the relationship between strength of SARS-CoV-2 PCR signal (cycle threshold value) in wastewater and percentage of jail population that tested positive for COVID-19. Of 13,745 nasal specimens collected, 3.9% were COVID-positive (range 0%-29.5% per week). We observed a strong inverse correlation between diagnostic test positivity and cycle threshold value (r = -0.67; p<0.01). Wastewater-based surveillance represents an effective strategy for jailwide surveillance of COVID-19.


Assuntos
COVID-19 , Gastrópodes , Humanos , Animais , SARS-CoV-2/genética , COVID-19/diagnóstico , COVID-19/epidemiologia , Georgia/epidemiologia , Águas Residuárias , Prisões Locais , Pandemias , RNA Viral
3.
Appl Environ Microbiol ; 89(4): e0196422, 2023 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-36951592

RESUMO

In this study, we investigated Bartonella infection and its genetic diversity in rodents in Beitun, Xinjiang Uygur Autonomous Region, China. Small mammals were captured using snap traps at four sampling sites in 2018. Spleen and liver tissues were collected and cultured to isolate Bartonella strains. Whole-genome sequencing was performed on the strains identified as Bartonella by gltA gene PCR, and the average nucleotide identity (ANI) of the genomes was calculated by using FastANI v1.33. Phylogenetic trees were constructed for the samples positive for Bartonella spp. by the gltA PCR assay based on 1,290-bp gltA genes, 2,903-bp rpoB genes, and core-genome single nucleotide polymorphisms (SNPs). Among 66 rodents, 11 were positive for Bartonella, with an infection rate of 16.67%. The rodent infection rates in different tissues (χ2 = 2.133; P = 0.242), species (χ2 = 9.631; P = 0.141), and habitats (χ2 = 4.309; P = 0.312) did not show statistical differences. Bartonella spp. isolated from the rodents were phylogenetically divided into six clades (two different Bartonella species were detected in two rodents). By comparing phylogenetic trees based on gltA genes, rpoB genes, and SNPs, we found that the topological structures of several evolutionary trees are different. However, the Bartonella strains isolated in this study were clustered into six clusters in different phylogenetic trees. Broad distributions and high genetic diversity of Bartonella strains were observed among rodents in Beitun, Xinjiang. IMPORTANCE Rodent-borne Bartonella species have been associated with zoonotic diseases. Bartonella species such as Bartonella elizabethae, Bartonella grahamii, and Bartonella tribocorum can cause disease in humans. Humans can be infected by blood-sucking arthropods through the scratches and bites of an infected reservoir host or via contact with infectious rodents. Xinjiang is one of the provinces with the most abundant species of Bartonella in China, but there are few reports about the prevalence of Bartonella in the Beitun area. This research aims to investigate the occurrence and prevalence of Bartonella infection in rodents at these sampling sites and provide a basis for the prevention and control of rodent Bartonella species in Beitun and the surrounding areas of Xinjiang.


Assuntos
Infecções por Bartonella , Bartonella , Animais , Humanos , Roedores , Filogenia , Prevalência , Bartonella/genética , Infecções por Bartonella/epidemiologia , Infecções por Bartonella/veterinária , China/epidemiologia
4.
Opt Express ; 31(5): 7983-7993, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36859917

RESUMO

In order to increase the optical path and related sensitivity of photometers, multiple axial-reflection of parallel light-beam inside a capillary cavity is one of the most effective ways. However, there is a non-optimum trade-off between optical path and light intensity, e.g., smaller aperture on cavity mirror can increase multiple axial-reflection times (i.e., longer optical path) due to the lower cavity-loss, but it would also reduce coupling efficiency, light intensity, and related signal-to-noise ratio. Herein, an optical beam shaper, which is composed of two optical lenses with an apertured mirror, was proposed to focus the light beam (i.e., increasing coupling efficiency) without deteriorating beam parallelism and related multiple axial-reflection. Thus, by combining the optical beam shaper with a capillary cavity, large optical path enhancement (10-fold of capillary length) and high coupling efficiency (>65%) can be realized simultaneously, where the coupling efficiency was improved 50-fold. An optical beam shaper photometer (with a 7 cm long capillary) was fabricated and applied to detect water in ethanol with a detection limit of 12.5 ppm, which is 800-fold and 32∼80 fold lower than that of the commercial spectrometer (1 cm cuvette) and previous reports, respectively.

5.
J Phys Chem A ; 127(36): 7510-7517, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37647565

RESUMO

The Stone-Wales defect is a well-known and significant defective structure in carbon materials, impacting their mechanical, chemical, and electronic properties. Recently, a novel metal-carbon nanomaterial named Volleyballene was discovered, characterized by a C-C bond bridging two carbon pentagons. Using first-principles calculations, a stable Stone-Wales-defective counterpart of Volleyballene, exhibiting Th symmetry, has been proposed by rotating the C-C bond by 90°. Although its binding energy per atom is slightly higher than that of Volleyballene (ΔEb = 0.009 eV/atom), implying marginally lower structural stability, it can maintain its bond structure until the effective temperature reaches about 1500 K, indicating greater thermodynamic stability. Additionally, its highest vibration frequency is 1346.2 cm-1, indicating a strong chemical bond strength. A theoretical analysis of the Sc20C60 + Sc20C60 binary systems highlights that the stable building block may be applied in potential nanoassemblies.

6.
Sensors (Basel) ; 23(9)2023 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-37177741

RESUMO

The current technological world is growing rapidly and each aspect of life is being transformed toward automation for human comfort and reliability. With autonomous vehicle technology, the communication gap between the driver and the traditional vehicle is being reduced through multiple technologies and methods. In this regard, state-of-the-art methods have proposed several approaches for advanced driver assistance systems (ADAS) to meet the requirement of a level-5 autonomous vehicle. Consequently, this work explores the role of textual cues present in the outer environment for finding the desired locations and assisting the driver where to stop. Firstly, the driver inputs the keywords of the desired location to assist the proposed system. Secondly, the system will start sensing the textual cues present in the outer environment through natural language processing techniques. Thirdly, the system keeps matching the similar keywords input by the driver and the outer environment using similarity learning. Whenever the system finds a location having any similar keyword in the outer environment, the system informs the driver, slows down, and applies the brake to stop. The experimental results on four benchmark datasets show the efficiency and accuracy of the proposed system for finding the desired locations by sensing textual cues in autonomous vehicles.

7.
J Infect Dis ; 226(10): 1771-1780, 2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-35137154

RESUMO

BACKGROUND: Genogroup II noroviruses are the most common cause of acute infectious gastroenteritis. We evaluated the use of a new GII.2 inoculum in a human challenge. METHODS: Forty-four healthy adults (36 secretor-positive and 8 secretor-negative for histo-blood group antigens) were challenged with ascending doses of a new safety-tested Snow Mountain virus (SMV) GII.2 norovirus inoculum (1.2 × 104 to 1.2 × 107 genome equivalent copies [GEC]; n = 38) or placebo (n = 6). Illness was defined as diarrhea and/or vomiting postchallenge in subjects with evidence of infection (defined as GII.2 norovirus RNA detection in stool and/or anti-SMV immunoglobulin G [IgG] seroconversion). RESULTS: The highest dose was associated with SMV infection in 90%, and illness in 70% of subjects with 10 of 12 secretor-positive (83%) and 4 of 8 secretor-negative (50%) becoming ill. There was no association between prechallenge anti-SMV serum IgG concentration, carbohydrate-binding blockade antibody, or salivary immunoglobulin A and infection. The median infectious dose (ID50) was 5.1 × 105 GEC. CONCLUSIONS: High rates of infection and illness were observed in both secretor-positive and secretor-negative subjects in this challenge study. However, a high dose will be required to achieve the target of 75% illness to make this an efficient model for evaluating potential norovirus vaccines and therapeutics. CLINICAL TRIALS REGISTRATION: NCT02473224.


Assuntos
Infecções por Caliciviridae , Gastroenterite , Norovirus , Adulto , Humanos , Norovirus/genética , Diarreia , Genótipo , Imunoglobulina G
8.
J Infect Dis ; 224(12 Suppl 2): S248-S257, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34469560

RESUMO

BACKGROUND: Streptococcus pneumoniae, or pneumococcus, is a leading cause of morbidity and mortality in children worldwide. Pneumococcal conjugate vaccines (PCV) reduce carriage in the nasopharynx, preventing disease. We conducted a pneumococcal carriage study to estimate the prevalence of pneumococcal colonization, identify risk factors for colonization, and describe antimicrobial susceptibility patterns among pneumococci colonizing young children in Port-au-Prince, Haiti, before introduction of 13-valent PCV (PCV13). METHODS: We conducted a cross-sectional study of children aged 6-24 months at an immunization clinic in Port-au-Prince between September 2015 and January 2016. Consenting parents were interviewed about factors associated with pneumococcal carriage; nasopharyngeal swabs were collected from each child and cultured for pneumococcus after broth enrichment. Pneumococcal isolates were serotyped and underwent antimicrobial susceptibility testing. We compared frequency of demographic, clinical, and environmental factors among pneumococcus-colonized children (carriers) to those who were not colonized (noncarriers) using unadjusted bivariate analysis and multivariate logistic regression. RESULTS: Pneumococcus was isolated from 308 of the 685 (45.0%) children enrolled. Overall, 157 isolates (50.8%) were PCV13 vaccine-type serotypes; most common were 6A (13.3%), 19F (12.6%), 6B (9.7%), and 23F (6.1%). Vaccine-type isolates were significantly more likely to be nonsusceptible to ≥1 antimicrobial (63.1% vs 45.4%, P = .002). On bivariate analysis, carriers were significantly more likely than noncarriers to live in a household without electricity or running water, to share a bedroom with ≥3 people, to have a mother or father who did not complete secondary education, and to have respiratory symptoms in the 24 hours before enrollment (P < .05 for all comparisons). On multivariable analysis, completion of the pentavalent vaccination series (targeting diphtheria, pertussis, tetanus, hepatitis B, and Haemophilus influenzae type b) remained significantly more common among noncarriers. CONCLUSIONS: Nearly a quarter of healthy children surveyed in Haiti were colonized with vaccine-type pneumococcal serotypes. This baseline carriage study will enable estimation of vaccine impact following nationwide introduction of PCV13.


Assuntos
Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Nasofaringe/microbiologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae , Antibacterianos/farmacologia , Pré-Escolar , Estudos Transversais , Feminino , Haiti/epidemiologia , Humanos , Lactente , Masculino , Sorogrupo
9.
J Med Virol ; 93(6): 3557-3563, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33017074

RESUMO

Noroviruses (NoV) are a leading cause of epidemic gastroenteritis. Human challenge studies have been used to examine the infectivity, pathogenicity, and host immune response to NoV as well as vaccine efficacy. The goal of this study was to conduct a meta-analysis of data from five previously completed human challenge trials and compare the response to the secondary NV inoculum (8fIIb) to its precursor (8fIIa). We investigated a total of 158 subjects: 76 subjects were experimentally challenged with NV inoculum 8fIIa, and 82 subjects were challenged with 8fIIb. We compared demographic characteristics, infection, illness, mean severity score, blood types, and duration of viral shedding between the two groups of subjects. There were no statistically significant differences in overall infection and illness rates between subjects inoculated with 8fIIa and 8fIIb. However, individuals challenged with 8fIIa had significantly higher severity scores (5.05 vs. 3.22, p = .008) compared with those challenged with 8fIIb. We also observed that infection with 8fIIb was associated with significantly longer duration of viral shedding compared with 8fIIa (11.0 days vs. 5.0 days, p = .0005). These results have serious implications for the development of new NoV inocula for human challenge studies to test candidate vaccine efficacy-where illness severity and duration of viral shedding are important outcomes.


Assuntos
Infecções por Caliciviridae/virologia , Vírus Norwalk/classificação , Vírus Norwalk/patogenicidade , Eliminação de Partículas Virais , Adolescente , Adulto , Infecções por Caliciviridae/imunologia , Relação Dose-Resposta Imunológica , Feminino , Gastroenterite/virologia , Voluntários Saudáveis , Experimentação Humana/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Vírus Norwalk/genética , Vírus Norwalk/imunologia , Índice de Gravidade de Doença , Adulto Jovem
10.
Analyst ; 146(18): 5474-5495, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34515706

RESUMO

Acute myocardial infarction (AMI) is the main cause of death from cardiovascular diseases. Thus, early diagnosis of AMI is essential for the treatment of irreversible damage from myocardial infarction. Traditional electrocardiograms (ECG) cannot meet the specific detection of AMI. Cardiac troponin I (cTnI) is the main biomarker for the diagnosis of myocardial infarction, and the detection of cTnI content has become particularly important. In this review, we introduced and compared the advantages and disadvantages of various cTnI detection methods. We focused on the analysis and comparison of the main indicators and limitations of various cTnI biosensors, including the detection range, detection limit, specificity, repeatability, and stability. In particular, we pay more attention to the application and development of electrochemical biosensors in the diagnosis of cardiovascular diseases based on different biological components. The application of electrochemical microfluidic chips for cTnI was also briefly introduced in this review. Finally, this review also briefly discusses the unresolved challenges of electrochemical detection and the expectations for improvement in the detection of cTnI biosensing in the future.


Assuntos
Técnicas Biossensoriais , Infarto do Miocárdio , Biomarcadores , Diagnóstico Precoce , Humanos , Infarto do Miocárdio/diagnóstico , Troponina I
11.
Nanotechnology ; 32(32)2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-33910184

RESUMO

The photostability issue of CsPbX3(X = Cl, Br, I) quantum dots (QDs) is one of the key origins for the degradation of their luminescence performance, which hinders their application in lighting and displays. Herein, we report a new method combining doping and ligand engineering, which effectively improves the photostability of CsPbBr3QDs and the performance of QD light-emitting diodes (QLEDs). In this method, ZnBr2is doped into CsPbBr3QDs to reduce surface anion defects; didodecyldimethyl ammonium bromide (DDAB) and tetraoctylammonium bromide (TOAB) hybrid ligands, which have strong adsorption with QDs, are employed to protect the surface and enhance the conductivity of QD layer in QLEDs. The photoluminescence (PL) and transmission electron microscopy measurements prove the effectively improved photostability of CsPbX3QDs. Moreover, reduced defects and improved conductivity by doping and hybrid ligands treatment also enable the improved electroluminescence performance of CsPbX3QDs. The maximum luminance and external quantum efficiency of the QLED with optimized CsPbX3QDs are 3518.9 cd m-2and 5.07%, which are 3.6 and 2.1 times than that of the control device, respectively. Combining doping and hybrid ligands makes perovskite QDs have an extremely promising prospect in future applications of high-definition displays, high-quality lighting, as well as solar cells.

12.
Appl Opt ; 60(17): 5245-5251, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34143094

RESUMO

We experimentally reveal the potential security risks for chaotic semiconductor lasers caused by time-delay signature (TDS). In order to eliminate TDS and enhance effective bandwidth, we propose a new scheme by introducing phase-modulation injection using Gaussian noise or pseudo-random binary sequence (PRBS) as phase-modulation signals. Our numerical results indicate that TDS elimination and bandwidth enhancement are obtained over a wide-parameter region of injection strength and frequency detuning. We further improve the scheme by using two channels of chaotic lasers to generate phase-modulation signals. Numerical simulation results show that the improved scheme is feasible, and TDS cancellation quality is always excellent in wide phase-modulation depth ranges.

13.
Sensors (Basel) ; 20(16)2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823502

RESUMO

The CNT-PDMS composite has been widely adopted in flexible devices due to its high elasticity, piezoresistivity, and biocompatibility. In a wide range of applications, CNT-PDMS composite sensors were used for resistive strain measurement. Accordingly, the percolation threshold 2%~4% of the CNT weight ratio in the CNT-PDMS composite was commonly selected, which is expected to achieve the optimized piezoresistive sensitivity. However, the linear range around the percolation threshold weight ratio (2%~4%) limits its application in a stable output of large strain (>20%). Therefore, comprehensive understanding of the electromechanical, mechanical, and electrical properties for the CNT-PDMS composite with different CNT weight ratios was expected. In this paper, a systematic study was conducted on the piezoresistivity, Young's modulus, conductivity, impedance, and the cross-section morphology of different CNT weight ratios (1 to 10 wt%) of the CNT-PDMS composite material. It was experimentally observed that the piezo-resistive sensitivity of CNT-PDMS negatively correlated with the increase in the CNT weight ratio. However, the electrical conductivity, Young's modulus, tensile strength, and the linear range of piezoresistive response of the CNT-PDMS composite positively correlated with the increase in CNT weight ratio. Furthermore, the mechanism of these phenomena was analyzed through the cross-section morphology of the CNT-PDMS composite material by using SEM imaging. From this analysis, a guideline was proposed for large strain (40%) measurement applications (e.g., motion monitoring of the human body of the finger, arm, foot, etc.), the CNT weight ratio 8 wt% was suggested to achieve the best piezoresistive sensitivity in the linear range.


Assuntos
Monitorização Fisiológica , Nanotubos de Carbono , Módulo de Elasticidade , Elasticidade , Condutividade Elétrica , Humanos , Resistência à Tração
14.
Entropy (Basel) ; 22(7)2020 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-33286557

RESUMO

The countermeasure of driver fatigue is valuable for reducing the risk of accidents caused by vigilance failure during prolonged driving. Listening to the radio (RADIO) has been proven to be a relatively effective "in-car" countermeasure. However, the connectivity analysis, which can be used to investigate its alerting effect, is subject to the issue of signal mixing. In this study, we propose a novel framework based on clustering and entropy to improve the performance of the connectivity analysis to reveal the effect of RADIO to maintain driver alertness. Regardless of reducing signal mixing, we introduce clustering algorithm to classify the functional connections with their nodes into different categories to mine the effective information of the alerting effect. Differential entropy (DE) is employed to measure the information content in different brain regions after clustering. Compared with the Louvain-based community detection method, the proposed method shows more superior ability to present RADIO effectin confused functional connection matrices. Our experimental results reveal that the active connection clusters distinguished by the proposed method gradually move from frontal region to parieto-occipital regionwith the progress of fatigue, consistent with the alpha energy changes in these two brain areas. The active class of the clusters in parieto-occipital region significantly decreases and the most active clusters remain in the frontal region when RADIO is taken. The estimation results of DE confirm the significant change (p < 0.05) of information content due to the cluster movements. Hence, preventing the movement of the active clusters from frontal region to parieto-occipital region may correlate with maintaining driver alertness. The revelation of alerting effect is helpful for the targeted upgrade of fatigue countermeasures.

15.
Appl Opt ; 58(1): 62-68, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30645513

RESUMO

The statistical properties of the noise in the Mie lidar signal are analyzed by the statistical hypotheses testing method. Based on this, an adaptive filter is proposed to eliminate the noise. The least mean square error algorithm is used to achieve optimal filtering, in which the mean square error is minimized by adjusting the filter's weight matrix. The validity of the adaptive filter is verified by numerical simulation and experimental data retrieving. In the numerical simulation, the signal-to-noise ratio of the adaptive filter is larger than that of the wavelet transform filter, and the mean square error of the output of the adaptive filter is less than the wavelet transform filter. In experimental data retrieving, the filtered lidar signals of the adaptive filter and wavelet transform filter are used to retrieve the extinction coefficient respectively in different weather conditions. The amplitude of the ripples in the extinction coefficient profile of the adaptive filter is less than that of the wavelet transform filter. Additionally, the adaptive filter's extinction coefficient profile is smoother than that of the wavelet transform filter. The detail of the extinction coefficient is displayed more clearly in the profile of the adaptive filter. The research result is of great importance for improving the accuracy of lidar data retrieving.

16.
J Med Ethics ; 44(9): 651-652, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29487117

RESUMO

This paper critically examines Barclay's conception of dignity proposed in her 'Dignitarian Medical Ethics'. According to Barclay, a subject S enjoys dignity if and only if S is reliably treated as having equal social status. I argue that Barclay's view faces a number of practical and theoretical problems. First, it is not obvious that failing to treat someone as a social equal is incompatible with respecting her dignity. Second, it is not always clear what treating someone as a social equal amounts to in practice. To be more compelling, her conception of dignity needs to be supplemented with a more principled and substantive account of the content of equal treatment.


Assuntos
Bioética , Respeito , Ética Médica , Feminino , Humanos
17.
Food Microbiol ; 76: 346-353, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30166160

RESUMO

Plant polyphenols have shown antiviral activity against several human pathogens, but their physicochemical interactions are not well-understood. The objectives of this study were to compare the antiviral activity between monomeric catechin and dimeric procyanidin B2 (PB2) using cultivable human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and to understand their potential antiviral mechanism using virus-like particles (VLPs) and the P domain of human norovirus GII (HNoV GII.4). Surrogate viruses at 5 log PFU/mL were treated with 0.5-5 mg/mL monomeric catechin monohydrate, PB2 or phosphate buffered saline (PBS, pH 7.2; control) at 37 °C over 24 h. Infectivity was determined using plaque assays and data from triplicate experiments were statistically analyzed. PB2 at 0.5 mg/mL and 1 mg/mL reduced FCV-F9 to undetectable levels after 3 h and MNV-1 by 0.21 and 1.23 log PFU after 24 h, respectively. Monomeric catechins at 1 mg/mL reduced FCV-F9 to undetectable levels after 6 h and MNV-1 titers to undetectable levels after 24 h. In addition, PB2 was shown to directly bind the P domain, the main capsid structure of HNoVs in the ratio of 1:1 through spontaneous interactions. Electrostatic interactions played a dominant role between PB2 and the P domain. PB2 significantly altered tertiary but not secondary structures of VLPs. Transmission electron microscopy demonstrated that PB2 aggregated VLPs, further indicating interactions between them. These findings indicate that PB2 causes structural changes of the P domain of VLPs, mainly through direct interaction leading to HNoV inactivation.


Assuntos
Antivirais/farmacologia , Biflavonoides/farmacologia , Calicivirus Felino/efeitos dos fármacos , Catequina/farmacologia , Proantocianidinas/farmacologia , Inativação de Vírus/efeitos dos fármacos , Animais , Antivirais/metabolismo , Biflavonoides/metabolismo , Calicivirus Felino/metabolismo , Catequina/metabolismo , Gatos , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Norovirus/efeitos dos fármacos , Proantocianidinas/metabolismo , Ensaio de Placa Viral , Ligação Viral
18.
Foodborne Pathog Dis ; 12(6): 500-5, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25789571

RESUMO

OBJECTIVE: The objective of this study was to investigate the seroepidemiology of immunoglobulin G (IgG) antibodies against Norovirus (NoV) GII.3 and GII.4 genotypes among children younger than 5 years with acute diarrhea in Xi'an, China. MATERIALS AND METHODS: A total of 362 serum samples were collected from diarrheal children in the Department of Digestive Diseases of Xi'an Children's Hospital between March 2009 and October 2012. Recombinant capsid proteins of NoV genotypes GII.3 and GII.4 were expressed using the baculovirus expression system. The viruslike particles (VLPs) were examined by electron microscopy and Western blot, and VLPs were used as antigens for serological IgG tests using enzyme-linked immunosorbent assays. RESULTS: The overall seroprevalence for GII.4 (86.2%) was significantly higher (p<0.01) than for GII.3 (67.9%). The seroprevalence remained in a high and stable level (70.9% for GII.3 and 88.7% for GII.4) in children under 1 year of age, then dropped in the age group 12-17 months (49.3% for GII.3 and 68.1% for GII.4), and finally increased to 77.8% for GII.3 and 96.8% for GII.4 in the group >18 months. The seroprevalence in the age group 12-17 months showed more statistically significant differences than the other age groups for both GII.3 and GII.4 (p<0.05). CONCLUSIONS: In conclusion, seroprevalence of NoV GII.3 and GII.4 was high in young children in Xi'an, China, and the anti-GII.4-positive rates were statistically higher than GII.3 across all the age groups.


Assuntos
Infecções por Caliciviridae/epidemiologia , Diarreia Infantil/etiologia , Diarreia/etiologia , Gastroenterite/epidemiologia , Norovirus/imunologia , Doença Aguda , Fatores Etários , Anticorpos Antivirais/análise , Infecções por Caliciviridae/sangue , Infecções por Caliciviridae/fisiopatologia , Infecções por Caliciviridae/virologia , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Pré-Escolar , China/epidemiologia , Suscetibilidade a Doenças , Fezes/virologia , Feminino , Gastroenterite/sangue , Gastroenterite/fisiopatologia , Gastroenterite/virologia , Hospitais Pediátricos , Humanos , Imunoglobulina G/análise , Lactente , Masculino , Tipagem Molecular , Norovirus/classificação , Norovirus/isolamento & purificação , Norovirus/ultraestrutura , Proteínas Recombinantes/metabolismo , Estudos Soroepidemiológicos
19.
J Med Virol ; 86(7): 1203-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24115094

RESUMO

Norovirus (NoV) is a leading cause of acute viral gastroenteritis among children, yet its burden of disease among immunocompromised hosts and its role in hospital acquired infections (HAI) is not well characterized. To determine the prevalence, genotypes, and NoV loads among immunocompromised children and children with HAI, residual stool samples, and clinical data were collected at two major pediatric hospitals in metropolitan Atlanta from 92 children that were immunocompromised and/or had a hospital acquired acute gastroenteritis. NoV was identified in 16.3% (15/92) of all stool specimens; 23.4% (11/47) in immunocompromised only children, and 13.3% (4/30) in children with HAI. All NoV positive cases were genogroup II (GII), and GII.4 was the predominant strain followed by GII.3, GII.12, and GII.13. The average NoV load for immunocompromised patients was 6.3 ± 1.4 log genome equivalent copies (GEC) per gram of stool compared to 5.8 ± 1.1 log GEC among patients with HAI. NoV infections are common among immunocompromised children and children with hospital-acquired gastroenteritis, underscoring the urgent need for rapid NoV detection system, and highlighting the importance of strict hospital hygiene practices.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecção Hospitalar/epidemiologia , Gastroenterite/epidemiologia , Norovirus/isolamento & purificação , Adolescente , Infecções por Caliciviridae/virologia , Criança , Pré-Escolar , Infecção Hospitalar/virologia , Fezes/virologia , Feminino , Gastroenterite/virologia , Genótipo , Georgia/epidemiologia , Humanos , Hospedeiro Imunocomprometido , Lactente , Recém-Nascido , Masculino , Norovirus/classificação , Norovirus/genética , Prevalência , Carga Viral
20.
Opt Express ; 22(26): 31977-83, 2014 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-25607165

RESUMO

An all glass optofludic biosensor with high quality-factor Fabry-Perot cavity (FPC) channel was reported. The all glass sandwich structure can completely eliminate the etching roughness of the channel surface, and can extend the operating wavelength to visible and ultraviolet regions compared with that of Si-based sensor. The quality-factor of the FPC channel is 875, and the system noise can be reduced to 1.2 nV by combining optical differential detection with phase lock-in detection. A detection limit of 15ng/mL for glucose solution, which corresponds to a refractive index unit of 2.0 × 10-9, was experimentally demonstrated. The all glass FPC sensor features low cost and robust compared with surface-plasmon-resonance sensor and ring-resonator sensor.


Assuntos
Técnicas Biossensoriais/instrumentação , Vidro/química , Interferometria/instrumentação , Microquímica/instrumentação , Microfluídica/instrumentação , Fotometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Glucose/análise , Integração de Sistemas
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