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1.
BMC Med Inform Decis Mak ; 23(1): 115, 2023 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-37415186

RESUMO

Deep learning models have been widely used in electroencephalogram (EEG) analysis and obtained excellent performance. But the adversarial attack and defense for them should be thoroughly studied before putting them into safety-sensitive use. This work exposes an important safety issue in deep-learning-based brain disease diagnostic systems by examining the vulnerability of deep learning models for diagnosing epilepsy with brain electrical activity mappings (BEAMs) to white-box attacks. It proposes two methods, Gradient Perturbations of BEAMs (GPBEAM), and Gradient Perturbations of BEAMs with Differential Evolution (GPBEAM-DE), which generate EEG adversarial samples, for the first time by perturbing BEAMs densely and sparsely respectively, and find that these BEAMs-based adversarial samples can easily mislead deep learning models. The experiments use the EEG data from CHB-MIT dataset and two types of victim models each of which has four different deep neural network (DNN) architectures. It is shown that: (1) these BEAM-based adversarial samples produced by the proposed methods in this paper are aggressive to BEAM-related victim models which use BEAMs as the input to internal DNN architectures, but unaggressive to EEG-related victim models which have raw EEG as the input to internal DNN architectures, with the top success rate of attacking BEAM-related models up to 0.8 while the top success rate of attacking EEG-related models only 0.01; (2) GPBEAM-DE outperforms GPBEAM when they are attacking the same victim model under a same distortion constraint, with the top attack success rate 0.8 for the former and 0.59 for the latter; (3) a simple modification to the GPBEAM/GPBEAM-DE will make it have aggressiveness to both BEAMs-related and EEG-related models (with top attack success rate 0.8 and 0.64), and this capacity enhancement is done without any cost of distortion increment. The goal of this study is not to attack any of EEG medical diagnostic systems, but to raise concerns about the safety of deep learning models and hope to lead to a safer design.


Assuntos
Aprendizado Profundo , Epilepsia , Humanos , Mapeamento Encefálico , Epilepsia/diagnóstico , Encéfalo , Eletroencefalografia
2.
Int J Mol Sci ; 24(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37108300

RESUMO

Due to the poor metabolic conditions fomenting the emergence of the Warburg effect (WE) phenotype, abnormal glycometabolism has become a unique and fundamental research topic in the field of tumor biology. Moreover, hyperglycemia and hyperinsulinism are associated with poor outcomes in patients with breast cancer. However, there are a few studies on anticancer drugs targeting glycometabolism in breast cancer. We hypothesized that Oxabicycloheptene sulfonate (OBHS), a class of compounds that function as selective estrogen receptor modulators, may hold potential in a therapy for breast cancer glycometabolism. Here, we evaluated concentrations of glucose, glucose transporters, lactate, 40 metabolic intermediates, and glycolytic enzymes using an enzyme-linked immunosorbent assay, Western blotting, and targeted metabolomic analysis in, in vitro and in vivo breast cancer models. OBHS significantly inhibited the expression of glucose transporter 1 (GLUT1) via PI3K/Akt signaling pathway to suppress breast cancer progression and proliferation. Following an investigation of the modulatory effect of OBHS on breast cancer cells, we found that OBHS suppressed the glucose phosphorylation and oxidative phosphorylation of glycolytic enzymes, leading to the decreased biological synthesis of ATP. This study was novel in highlighting the role of OBHS in the remodeling of tumor glycometabolism in breast cancer, and this is worth further investigation of breast cancer in clinical trials.


Assuntos
Neoplasias , Fosfatidilinositol 3-Quinases , Humanos , Transportador de Glucose Tipo 1/genética , Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias/metabolismo , Glucose/metabolismo , Linhagem Celular Tumoral
3.
Sensors (Basel) ; 22(14)2022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35891051

RESUMO

In this letter, we propose a nonlinear Magnetoelastic Energy (ME) with a material parameter related to electron interactions. An attenuating term is contained in the formula of the proposed nonlinear ME, which can predict the variation in the anisotropic magneto-crystalline constants induced by external stress more accurately than the classical linear ME. The domain wall velocity under stress and magnetic field can be predicted accurately based on the nonlinear ME. The proposed nonlinear ME model is concise and easy to use. It is important in sensor analysis and production, magneto-acoustic coupling motivation, magnetoelastic excitation, etc.

4.
Environ Monit Assess ; 194(7): 495, 2022 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-35691976

RESUMO

Risks brought by climate change are inevitable obstacles to global development. Clarifying the features of climate change risks helps us to further understand and cope with climate change. There lacks a systematic review of climate change risks in terms of feature extraction and classification. The bibliometric analysis can be used to analyze and extract climate change risk features. The literature in the field of climate change was searched in the Web of Science database. Coauthors, citations, bibliographic coupling, co-citations, and keyword co-occurrence were analyzed. From five dimensions including nature, politics, economy, society, and culture, the risk features of climate change were extracted and summarized. Through text mining and cluster analysis, the climate change risk feature system was established, which is embodied in five different aspects: ecosystem and sustainability; uncertainty, vulnerability, and efficiency; behavior and decision-making; governance and management; and adaptation and mitigation. The feature system reflects that the current climate change risk presents strong variability and that the risk boundary is gradually blurred. The areas affected by risk are expanding and deepening. The strategies and governance for addressing risks are gradually diversified. This research contributes to the domain of climate change risk identification and assessment. The features of climate change indicate that we need to adjust policymaking and managerial practices for climate change in the future. Interdisciplinary cooperation, human cognition and preferences, public participation in global governance, and other unnatural factors related to climate change should be strengthened with a more positive attitude.


Assuntos
Mudança Climática , Ecossistema , Aclimatação , Bibliometria , Monitoramento Ambiental
5.
J Infect Chemother ; 27(5): 696-701, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33358402

RESUMO

OBJECTIVES: Candida albicans and Candida auris strains are common causative species of Candidiasis. The limited number of antifungal drugs and the current situation of resistance to existing antifungals force us to search for new antifungal alternatives. METHODS: In this work, primary screening of small molecule libraries (Metabolism Compound Library and Epigenetics Compound Library) consisting of 584 compounds against Candida albicans SC5314 was performed. The dose-response assays, XTT assays, scanning electron microscopy and confocal laser scanning microscopy were used to confirm the antifungal activities of the selected compounds against Candida strains. RESULTS: Through the primary screening, we identified five compounds (U73122, disulfiram, BSK805, BIX01294, and GSKJ4) that inhibited strains growth ≥ 80% for dose-response assays. Disulfiram was identified as the most potent repositionable antifungal drug with 50% growth inhibition detected at a concentration as low as 1 mg/L. The further results showed the antifungal activity of disulfiram against biofilm formation of Candida strains with a 50% minimum inhibitory concentration ranging from 32 to 128 mg/L. Further observations by scanning electron microscopy and confocal laser scanning microscopy confirmed the destruction of biofilm architecture and the change of biofilm morphology after being exposed to disulfiram. CONCLUSION: The study indicated the potential clinical application of disulfiram as a promising antifungal drug against candidiasis.


Assuntos
Antifúngicos , Preparações Farmacêuticas , Antifúngicos/farmacologia , Biofilmes , Candida , Candida albicans , Dissulfiram/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Bibliotecas de Moléculas Pequenas/farmacologia
6.
Sensors (Basel) ; 19(2)2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30658471

RESUMO

In recent years, fire accidents in petrochemical plant areas and dangerous goods storage ports in China have shown a trend of frequent occurrence. Toxic and harmful gases are diffused in the scenes of these accidents, which causes great difficulties for fire fighting and rescue operations of fire fighting forces, and consequently, casualties of firefighters often occur. In order to ensure the safety of firefighters in such places, this paper designs a monitoring system of toxic and harmful gases specially used in fire fighting and rescue sites of fire forces, and establishes the transmission network, monitoring terminal and data processing software of the monitoring system of toxic and harmful gases, establishing the danger model of the monitoring area of toxic and harmful gas-monitoring terminal, and the danger model of fire fighters' working area, fusing the field toxic and harmful gas data, terminal positioning data, and field environmental data, designing the data structure of the input data set and the network structure of the RNN cyclic neural network model, and realizing the dynamic early warning of toxic and harmful gases on site.

7.
PLoS One ; 19(2): e0297108, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38422057

RESUMO

In recent years, considerable and valuable research progress has been made in indoor positioning technologies based on WLAN Radio Frequency (RF) fingerprinting, identifying it as one of the most promising positioning technologies with substantial potential for wider adoption. However, indoor environmental factors significantly influence the propagation of wireless RF signals, resulting in a considerable decrease in positioning accuracy as the indoor environmental conditions vary. Thus, effectively mitigating the impact of indoor environmental factors on WLAN RF fingerprinting-based positioning systems has become a crucial research problem. Currently, there is a dearth of comprehensive research on the influence of indoor climatic factors, particularly the variations in relative humidity, on the propagation of WLAN RF signals within indoor spaces and its consequential impact on positioning accuracy. To address the aforementioned issues, this paper proposes an Adaptive expansion fingerprint database (AeFd) model based on a regression learning algorithm. The AeFd, through the design of a relationship model describing the interaction between fingerprint databases under varying relative humidity, allows the fingerprint database expanded by AeFd to dynamically adapt to the changes in indoor relative humidity. Our experiments show that using the AeFd model with the KNN algorithm, a 5% performance improvement was observed over 10 days and an 8% improvement over 10 months. According to experimental test results, the fingerprint database expansion model AeFd proposed in this paper can effectively expand the fingerprint database under different relative humidity levels, thereby significantly enhancing the positioning performance of the system and improving its stability.


Assuntos
Algoritmos , Teoria Ética , Calibragem , Causalidade , Bases de Dados Factuais
8.
Microorganisms ; 12(5)2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38792738

RESUMO

Microbial communities inhabiting sedimentary environments in river source regions serve as pivotal indicators of pristine river ecosystems. While the correlation between antibiotic resistome and pathogenicity with core gut bacteria in humans is well established, there exists a significant knowledge gap concerning the interaction of antibiotic resistance genes (ARGs) and human pathogenic bacteria (HPB) with specific microbes in river source basins, often referred to as "terrestrial gut". Understanding the microbial composition, including bacteria and resident genetic elements such as ARGs, HPB, Mobile Genetic Elements (MGEs), and Virulence Factors (VFs), within natural habitats against the backdrop of global change, is imperative. To address this gap, an enrichment-based culturomics complementary along with metagenomics was conducted in this study to characterize the microbial biobank and provide preliminary ecological insights into profiling the dissemination of ARGs in the Lancang River Source Basin. Based on our findings, in the main stream of the Lancang River Source Basin, 674 strains of bacteria, comprising 540 strains under anaerobic conditions and 124 under aerobic conditions, were successfully isolated. Among these, 98 species were identified as known species, while 4 were potential novel species. Of these 98 species, 30 were HPB relevant to human health. Additionally, bacA and bacitracin emerged as the most abundant ARGs and antibiotics in this river, respectively. Furthermore, the risk assessment of ARGs predominantly indicated the lowest risk rank (Rank Ⅳ) in terms of endangering human health. In summary, enrichment-based culturomics proved effective in isolating rare and unknown bacteria, particularly under anaerobic conditions. The emergence of ARGs showed limited correlation with MGEs, indicating minimal threats to human health within the main stream of the Lancang River Source Basin.

9.
iScience ; 27(5): 109807, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38766355

RESUMO

Type I interferon (IFN) production is crucial in tuberculosis pathogenesis, yet the bacterial factors initiating this process are incompletely understood. CpsA, protein of Mycobacterium marinum and Mycobacterium tuberculosis, plays a key role in maintaining bacterial virulence and inhibiting host cell LC3-associated phagocytosis. By utilizing CpsA full deletion mutant studies, we re-verified its essential role in infection-induced pathology and revealed its new role in type I IFN expression. CpsA deficiency hindered IFN production in infected macrophages in vitro as well as zebrafish and mice in vivo. This effect was linked to the cGAS-TBK1-IRF3 pathway, as evidenced by decreased TBK1 and IRF3 phosphorylation in CpsA-deficient bacterial strain-infected macrophages. Moreover, we further show that CpsA deficiency cause decreased cytosolic DNA levels, correlating with impaired phagosomal membrane rupture. Our findings reveal a new function of mycobacterial CpsA in type I IFN production and offer insight into the molecular mechanisms underlying mycobacterial infection pathology.

10.
Environ Technol ; 34(17-20): 2853-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24527650

RESUMO

Landfill leachate is posing an ever-greater environmental hazard. Recently, a process for purification combining activated carbon, microwave (MW) and Fenton oxidation has drawn much attention. In this study, the effectiveness of this process for the pretreatment of an old-age landfill leachate was tested. The effects of various parameters were investigated and the optimal condition included as follows: MW energy density, 6 W/mL; MW power, 300 W; radiation time, 8 min; H2O2 dosage, 0.1 mol/L; Fe(2+)-EDTA dosage, 0.02 mol/L; granular activated carbon (GAC) dosage, 6 g/L. Within the present experimental condition applied, the chemical oxygen demand (COD) removal reached 56.5%, and the ratio of 5-day biochemical oxygen demand to chemical oxygen demand (BOD5/COD) was enhanced from 0.122 to 0.462. Comparing with GAC, MW and Fenton alone or the combinations of any two of them, MW/Fenton/GAC displayed superior treatment efficiency. The MW/Fenton/GAC process is believed to be a promising pretreatment technology for biorefractory old-age landfill leachate.


Assuntos
Carvão Vegetal/química , Peróxido de Hidrogênio/química , Ferro/química , Micro-Ondas , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Oxirredução
11.
Sci Rep ; 13(1): 12410, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37524999

RESUMO

To comprehensively understand the mechanical response of a rock-coal combination structure containing a weak layer, a series of laboratory static loading and impact loading experiments were conducted. The results showed that under static load, the sliding process of the rock coal structure was relatively slow, and fragments can be observed. Under the action of horizontal impact loading, the whole coal stratum slipped out rapidly, and the process lasted only 0.05 s. Under the horizontal and axial impact loads, the coal stratum remained stable first, and then it slipped out as a whole under the action of static load. Additionally, a sliding instability criterion of a rock coal structure containing a weak layer was established based on theoretical analysis. The key parameter P value was checked through a numerical simulation experiment. It was found that the value was linearly related to the mechanical properties of the weak layer and overburden stress, and the experimental results coincided with the theoretical results. Finally, the relationship between sliding rockburst and strain rockburst was discussed, and these results can provide an important scientific basis for the prevention and control of dynamic disasters in deep mining.

12.
Heliyon ; 9(4): e15336, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37123930

RESUMO

Traditional transplantation, surgical extrusion and intentional replantation procedures are important treatment options that clinicians may consider performing in their daily clinical practice. There should be a well-constructed treatment plan for teeth with problems. In this paper, we present a series of case reports on three treatment methods used in autologous tooth transplantation and a literature review on the prevention of postoperative complications and the advantages of autologous tooth transplantation compared to dental implantation. The purpose of this study was to improve the understanding of autologous tooth transplantation.

13.
Sci Total Environ ; 889: 164265, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37211102

RESUMO

Estuarine ecosystems undergo pronounced and intricate changes due to the mixing of freshwater and saltwater. Additionally, urbanization and population growth in estuarine regions result in shifts in the planktonic bacterial community and the accumulation of antibiotic resistance genes (ARGs). The dynamic changes in bacterial communities, environmental factors, and carriage of ARGs from freshwater to seawater, as well as the complex interrelationships among these factors, have yet to be fully elucidated. Here, we conducted a comprehensive study based on metagenomic sequencing and full-length 16S rRNA sequencing, covering the entire Pearl River Estuary (PRE) in Guangdong, China. The abundance and distribution of the bacterial community, ARGs, mobile genetic elements (MGEs), and bacterial virulence factors (VFs) were analyzed on a site-by-site basis through sampling along the salinity gradient in PRE, from upstream to downstream. The structure of the planktonic bacterial community undergoes continuous changes in response to variations in estuarine salinity, with the phyla Proteobacteria and Cyanobacteria being dominant bacterial throughout the entire region. The diversity and abundance of ARGs and MGEs gradually decreased with the direction of water flow. A large number of ARGs were carried by potentially pathogenic bacteria, especially in Alpha-proteobacteria and Beta-proteobacteria. Multi-drug resistance genes have the highest abundance and subtypes in PRE. In addition, ARGs are more linked to some MGEs than to specific bacterial taxa and disseminate mainly by HGT and not by vertical transfer in the bacterial communities. Various environmental factors, such as salinity and nutrient concentrations, have a significantly impact on the community structure and distribution of bacteria. In conclusion, our results represent a valuable resource for further investigating the intricate interplay between environmental factors and anthropogenic disturbances on bacterial community dynamics. Moreover, they contribute to a better understanding of the relative impact of these factors on the dissemination of ARGs.


Assuntos
Estuários , Genes Bacterianos , Ecossistema , Salinidade , RNA Ribossômico 16S/genética , Bactérias/genética , China
14.
Front Cell Infect Microbiol ; 11: 662344, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33968805

RESUMO

Attachment and specific binding to the receptor on the host cell surface is the first step in the process of bacteriophage infection. The lytic phage VP2 is used in phage subtyping of the Vibrio cholerae biotype El Tor of the O1 serogroup; however, its infection mechanism is poorly understood. In this study, we aimed to identify its receptor on V. cholerae. The outer membrane protein EpsD in the type II secretory system (T2SS) was found to be related to VP2-specific adsorption to V. cholerae, and the T2SS inner membrane protein EpsM had a role in successful VP2 infection, although it was not related to adsorption of VP2. The tail fiber protein gp20 of VP2 directly interacts with EpsD. Therefore, we found that in V. cholerae, in addition to the roles of the T2SS as the transport apparatus of cholera toxin secretion and filamentous phage release, the T2SS is also used as the receptor for phage infection and probably as the channel for phage DNA injection. Our study expands the understanding of the roles of the T2SS in bacteria.


Assuntos
Bacteriófagos , Cólera , Sistemas de Secreção Tipo II , Vibrio cholerae , Toxina da Cólera , Humanos , Proteínas de Membrana
15.
PLoS One ; 16(2): e0247418, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33617547

RESUMO

The increasing prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) caused nosocomial infections generate significant comorbidity and can cause death among patients. Current treatment options are limited. These infections pose great difficulties for infection control and clinical treatment. To identify the antimicrobial resistance, carbapenemases and genetic relatedness of Acinetobacter baumannii isolates from cerebrospinal fluid (CSF) and blood, a total of 50 nonrepetitive CSF isolates and 44 blood isolates were collected. The resistance phenotypes were determined, and polymerase chain reaction (PCR) was performed to examine the mechanisms of carbapenem resistance. Finally, multilocus sequence typing (MLST) was conducted to determine the genetic relatedness of these isolates. It was observed that 88 of the 94 collected isolates were resistant to imipenem or meropenem. Among them, the blaOXA-23 gene was the most prevalent carbapenemase gene, with an observed detection rate of 91.5% (86/94), followed by the blaOXA-24 gene with a 2.1% detection rate (2/94). Among all carbapenem-resistant Acinetobacter baumannii (CRAB) observations, isolates with the blaOXA-23 gene were resistant to both imipenem and meropenem. Interestingly, isolates positive for the blaOXA-24 gene but negative for the blaOXA-23 gene showed an imipenem-sensitive but meropenem-resistant phenotype. The MLST analysis identified 21 different sequence types (STs), with ST195, ST540 and ST208 most frequently detected (25.5%, 12.8% and 11.7%, respectively). 80 of the 94 isolates (85.1%) were clustered into CC92 which showed a carbapenem resistance phenotype (except AB13). Five novel STs were detected, and most of them belong to CRAB. In conclusion, these findings provide additional observations and epidemiological data of CSF and blood A. baumannii strains, which may improve future infection-control measures and aid in potential clinical treatments in hospitals and other clinical settings.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/uso terapêutico , Sangue/microbiologia , Líquido Cefalorraquidiano/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Acinetobacter baumannii/genética , Proteínas de Bactérias/genética , Carbapenêmicos/uso terapêutico , Humanos , Imipenem/uso terapêutico , Meropeném/uso terapêutico , Testes de Sensibilidade Microbiana/métodos , beta-Lactamases/genética
16.
ACS Appl Mater Interfaces ; 12(8): 10039-10049, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32017854

RESUMO

Superwetting surfaces that repel various liquids have been exciting for biomimetic research and have displayed versatile potential applications. Generally, superhydrophobic coatings can allow for droplet rolling off and antifouling, whereas it is a challenge to achieve superomniphobic surfaces with transparency, flexibility, and conductivity. Here, we adopt an effective and simple method to fabricate a superomniphobic, transparent, and flexible smart silk fibroin (SF) membrane by spray-coating long AgNWs dispersed in polydimethylsiloxane (PDMS), followed by treatment with vacuum drying. The resulting SF/AgNWs membranes are super-repellent to different liquids with low surface tension and water, and demonstrate high contact angles (CAs) more than 150° and low rolling-off angles (RAs) even less than 10°. Moreover, the obtained membranes display superior sensitivity under stretching and bending, as well as intact stability of high transparency, which can be considered as promising flexible sensing electronics to detect human motions under wet conditions.


Assuntos
Eletrônica , Fibroínas/química , Nanofios/química , Prata/química , Dimetilpolisiloxanos/química , Humanos
17.
Infect Genet Evol ; 81: 104238, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32045711

RESUMO

In Vibrio cholerae, the lysogenic bacteriophage CTXΦ carries the cholera toxin genes ctxAB, which can be transferred from toxigenic strains to nontoxigenic strains through infection and lysogenic conversion of CTXΦ. This phage also has the precursor genome which does not harbor ctxAB, named pre-CTXΦ. Based on the sequences of the transcriptional regulator-encoding gene rstR alleles in CTXΦ/pre-CTXΦ, multiple types of these prophages have been classified and identified in toxigenic and nontoxigenic V. cholerae strains. In this study, by combining the short-read and long-read sequencing approaches of next generation sequencing, we obtained the complete genome sequence of the studied V. cholerae toxigenic serogroup O139 strain and identified the CTXΦ and a pre-CTXΦ genome type encoding a novel rstR allele, pre-CTXZHJΦ. This pre-CTX prophage integrates into the small chromosome of the V. cholerae host strain and coexists with a typical CTXETΦ prophage present in the large chromosome, which is commonly present in the seventh pandemic serogroup O1 and toxigenic serogroup O139 strains. RstRZHJ could bind to the ig-2 region in the RstAB promotor in the pre-CTXZHJΦ genome, and could repress the expression of its own rstAB genes but could not repress rstAB expression in CTXETΦ and CTXclassΦ, suggesting that the V. cholerae strains carrying the pre-CTXZHJΦ prophage cannot prevent the infection of these epidemic CTXΦs, hence have the potentiality to become toxigenic by acquiring and lysogenic conversion of CTXΦs. Our study identified a novel pre-CTXΦ type, and presents the new evidence for the complexity and diversity of the CTXΦ/pre-CTXΦ family in V. cholerae.


Assuntos
Prófagos/genética , Vibrio cholerae O139/virologia , Bacteriófagos/genética , Cólera/virologia , Toxina da Cólera/genética , DNA Viral/genética , Genes Virais/genética , Genoma Viral/genética , Lisogenia/genética , Vibrio cholerae O1/virologia , Proteínas Virais/genética
18.
J Xray Sci Technol ; 17(3): 265-77, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19893217

RESUMO

An ultra-precision ELID grinding of large stamping dies of Wolter mirror for X-ray telescope was presented in this paper. The large stamping dies (S55C) with confocal paraboloid and hyperboloid was ground by ELID arc-enveloped grinding. In this ELID grinding system, cast iron fiber bonded (CIFB) diamond wheels were controlled by 3-dimentional ways to scan the work-piece and generate required surfaces. Its grinding characteristics such as attainable form accuracy, surface roughness were investigated. Furthermore, some measures to improve form accuracy were discussed and verified such as truing, compensating, and on-machine measuring.


Assuntos
Astronomia/instrumentação , Lentes , Difração de Raios X/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Difração de Raios X/métodos
19.
Gut Pathog ; 11: 38, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31338129

RESUMO

BACKGROUND: Hemolysis of bacteria is an important phenotype used for typing and characterizing strains with specific biomarkers and even a virulence factor in bacterial pathogenesis. In Vibrio cholerae, hemolysin HlyA is responsible for hemolysis of sheep red blood cells, and this hemolytic phenotype is used as a biotyping indicator and considered one of the virulence factors. At the beginning of the seventh cholera pandemic, the El Tor biotype strains of serogroup O1 were distinguished by hemolysis from the sixth pandemic O1 classical biotype strains, whereas during the following epidemics, nonhemolytic El Tor strains appeared, suggesting phenotypic and genetic variations in these strains. This study aimed to investigate the possible mechanisms involved in nonhemolysis of El Tor strains. RESULTS: Five sequence types of hlyA genes were found in the studied O1 El Tor strains isolated during the seventh pandemic. A 4-base deletion in hlyA caused the HlyA protein mutation and non-hemolytic phenotype. Some strains carry wildtype hlyA genes but are still non-hemolytic, and greatly reduced hlyA transcription and blocked secretion of hemolysin were observed in hemolysis tests of the subcellular components and transcription/expression analysis of hlyA. CONCLUSIONS: Mechanisms responsible for nonhemolysis of the epidemic O1 El Tor strains are complex and not only confined to gene mutation but also deficiencies of transcription and extracellular transport of HlyA. Mutations in gene regulation and protein secretion systems of HlyA in the nonhemolytic V. cholerae strains should be areas of concern in future studies.

20.
ACS Appl Mater Interfaces ; 11(28): 25295-25305, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31260237

RESUMO

Liquid metals (LMs) possess tremendous potential applications in flexible electronic devices, heat flow management, and smart actuators. Splitting the bulk LMs into microspheres is of great significance to fabricate free-standing and microscale LM-based functional materials and devices. However, it is difficult to disperse the bulk LMs into microspheres because of their large surface tension and high density. In this work, the capillary-based microfluidic chip is employed to continuously and automatically generate LM microspheres in a large scale. The capillary-based microfluidic fabrication is universally applicable in ionic aqueous solution, hydrophobic solution, and the polymeric aqueous solution. The precise size control of LM microspheres can be easily realized by the co-flowing configuration in the microchannels. The coefficient of size variation of monodispersed LM microspheres can be controlled to as low as 0.47%. The free-standing LM microspheres can be used as functional microelectrodes within a wide temperature range from -19.8 to 20 °C and to fabricate tunable integrated circuits with different output powers. Most importantly, the LM microspheres exhibit photothermal property, which is used to make the optical sensor with linear response and to conduct the solar energy harvesting. The capillary-based microfluidic fabrication of LM microspheres provides a facile and templated methodology for processing bulk LMs into microscale units. The LM microspheres with excellent electrical conductivity and photothermal property hold great promise for the development of miniature soft electronics, light-driven actuators, and energy conversion medium.

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