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1.
Nanoscale ; 13(38): 16113-16121, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34633011

RESUMO

The magnetic tunneling junction (MTJ) controlled by electric field as an alternate approach for energy efficiency is the highlight for nonvolatile RAM, while there is still a lack of research on resistance manipulation with the electric field in nanoscale MTJs. In this study, we integrated nanoscale MTJs on the (011) orientated Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) ferroelectric substrates and systematically investigated the magnetoresistance as a function of the magnetic field and electric field. A single domain state of the nanoscale MTJ was demonstrated by the experimental result and theoretical simulation. Afterward, the obvious electric field control of R-H curves was obtained and explained by the competition between magnetoelastic energy and shape anisotropy. More importantly, simulation results also predicted that the switching pathway of magnetic moments under the magnetic field is strongly dependent on the applied electric field, displaying the electric field control of chiral switching in the nano-MTJ. Our work is a milestone in the realization of the emerging dubbed straintronics field.

2.
Front Physiol ; 12: 717080, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34531762

RESUMO

Enhanced external counterpulsation is a Food and Drug Administration-approved, non-invasive, assisted circulation therapy for ischemic cardiovascular and cerebrovascular diseases. Previous studies have confirmed that EECP stimulation induces largely different cerebral hemodynamic responses in patients with ischemic stroke and healthy controls. However, the underlying mechanisms remain uncertain. We hypothesize that different blood redistributions at the carotid bifurcation may play a key role. Ten subjects were enrolled in this study, namely, five patients with neurological disorders and five young healthy volunteers as controls. Magnetic resonance angiography (MRA) was performed on the carotid artery. All the subjects received a single session of EECP treatment, with external cuff pressures ranging from 20 to 40 kPa. Vascular ultrasound measurements were taken in the common carotid artery (CCA), external carotid artery (ECA) and internal carotid artery (ICA). Three-dimensional patient-specific numerical models were developed to calculate the WSS-derived hemodynamic factors. The results indicated that EECP increased CCA and ECA blood flow in both groups. The ICA blood flow in the patient group exhibited a mean increase of 6.67% during EECP treatment compared with the pre-EECP condition; a mean decrease of 9.2% was observed in the healthy control group. EECP increased the averaged wall shear stress (AWSS) throughout the carotid bifurcation in the patient group; the ICA AWSS of the healthy group decreased during EECP. In both groups, the oscillatory shear index (OSI) in the ICA increased proportionally with external cuff pressure. In addition, the relative resident time (RRT) was constant or slightly decreased in the CCA and ECA in both groups but increased in the ICA. We suggest that the benefits of EECP to patients with neurological disorders may partly result from blood flow promotion in the ICA and increase in WSS at the carotid bifurcation. In the healthy subjects, the ICA blood flow remained constant during EECP, although the CCA blood flow increased significantly. A relatively low external cuff pressure (20 kPa) is recommended as the optimal treatment pressure for better hemodynamic effects. This study may play an important role in the translation of physiological benefits of EECP treatment in populations with or without neurological disorders.

3.
Front Cell Infect Microbiol ; 11: 695134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34368015

RESUMO

The objective of this study was to evaluate the value of molecular methods in the management of community-acquired pneumonia (CAP) in children. Previously developed mass spectrometry (MS)-based methods combined with quantitative real-time PCR (combined-MS methods) were used to describe the aetiology and evaluate antibiotic therapy in the enrolled children. Sputum collected from 302 children hospitalized with CAP were analyzed using the combined-MS methods, which can detect 19 viruses and 12 bacteria related to CAP. Based on the results, appropriate antibiotics were determined using national guidelines and compared with the initial empirical therapies. Respiratory pathogens were identified in 84.4% of the patients (255/302). Co-infection was the predominant infection pattern (51.7%, 156/302) and was primarily a bacterial-viral mixed infection (36.8%, 111/302). Compared with that using culture-based methods, the identification rate for bacteria using the combined-MS methods (61.8%, 126/204) increased by 28.5% (p <0.001). Based on the results of the combined-MS methods, the initial antibiotic treatment of 235 patients was not optimal, which mostly required switching to ß-lactam/ß-lactamase inhibitor combinations or reducing unnecessary macrolide treatments. Moreover, using the combined-MS methods to guide antibiotic therapy showed potential to decrease the length of stay in children with severe CAP. For children with CAP, quantitative molecular testing on sputum can serve as an important complement to traditional culture methods. Early aetiology elucidated using molecular testing can help guide the antibiotic therapy.


Assuntos
Infecções Comunitárias Adquiridas , Pneumonia , Antibacterianos/uso terapêutico , Bactérias/genética , Criança , Infecções Comunitárias Adquiridas/tratamento farmacológico , Humanos , Espectrometria de Massas , Pneumonia/tratamento farmacológico
4.
Artigo em Inglês | MEDLINE | ID: mdl-33593843

RESUMO

The growing antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a serious global threat to gonococcal therapy. Molecular typing is an ideal tool to reveal the association between specific genotype and resistance phenotype that provides effective data for tracking the transmission of resistant clones of N. gonorrhoeae In our study, we aimed to describe the molecular epidemiology of AMR and the distribution of resistance-associated genotypes in Shenzhen during 2014-2018. In total, 909 isolates were collected from Shenzhen from 2014-2018. Two typing schemes, multilocus sequence typing (MLST) and N. gonorrhoeae Sequence Typing for Antimicrobial Resistance (NG-STAR), were performed for all isolates. The distribution of resistance-associated genotypes was described using goeBURST analysis combined with data of logistic regression. Among 909 isolates, ST8123, ST7363, ST1901, ST7365, and ST7360 were most the common MLST sequence types (STs), and ST348, ST2473, ST497, and ST199 were the most prevalent NG-STAR STs. The logistic regression analysis showed that NG-STARST497, MLSTST7365, and MLSTST7360 were typically associated with decreased susceptibility to ceftriaxone. Furthermore, the internationally spreading ESC-resistant clone MLSTST1901 has been prevalent at least in 2014 in Shenzhen and showed a significant increase during 2014-2018. Additionally, MLSTST7363 owns the potential to become the next internationally spreading ceftriaxone-resistant ST. In conclusions, we performed a comprehensive epidemiological study to explore the correlation between AMR and specific STs, which provided important data for future studies of the molecular epidemiology of AMR in N. gonorrhoeae Besides, these findings provide insight for adjusting surveillance strategies and therapy management in Shenzhen.

5.
Microb Biotechnol ; 14(2): 668-676, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33277967

RESUMO

Chlamydia trachomatis is the most common sexually transmitted pathogen globally, causing serious health problems and representing a burden on public health. A new variant of C. trachomatis (nvCT) that carries mutations (C1514T, C1515T and G1523A) in the 23S rRNA gene has eluded detection in Aptima Combo 2 assays. This has led to false negatives in diagnostics tests and poses a challenge for C. trachomatis diagnostics on a global level. In this study, we developed a simple and cost-effective assay to identify C. trachomatis, with a potential application to screen for nvCT. We developed a screening assay based on high-resolution melting (HRM), targeting the 23S rRNA gene and cryptic plasmid. To evaluate the performance of the assay, 404 archived C. trachomatis DNA specimens and 570 extracted clinical specimens were analysed. Our HRM assay not only identified C. trachomatis in clinical specimens, but also correctly differentiated nvCT carrying C1514T, C1515T and G1523A mutations from the wild-type. We observed no cross-reactions with other clinically related agents, and the limit of detection was 11.26 (95% CI; 7.61-31.82) copies per reaction. Implementation of this screening assay could reduce detection times and costs for C. trachomatis diagnoses, and facilitate increased research on the presence and monitoring of nvCT.


Assuntos
Infecções por Chlamydia , Chlamydia trachomatis , Infecções por Chlamydia/diagnóstico , Chlamydia trachomatis/genética , Humanos , Programas de Rastreamento , Plasmídeos , RNA Ribossômico 23S/genética , Sensibilidade e Especificidade
6.
Clin Chem ; 67(4): 610-620, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33367585

RESUMO

BACKGROUND: Antimicrobial resistance (AMR) of Neisseria gonorrhoeae has spread worldwide. Rapid and comprehensive methods are needed to describe N. gonorrhoeae AMR profiles accurately. A method based on multiplex amplicon sequencing was developed to simultaneously sequence 13 genes related to AMR in N. gonorrhoeae directly from clinical samples. METHODS: Nine N. gonorrhoeae strains were used for the establishment and validation of the method. Eleven urethral swabs and their corresponding cultured isolates were matched as pairs to determine the accuracy of the method. Mock samples with different dilutions were prepared to determine the sensitivity of the method. Five nongonococcal Neisseria strains and 24 N. gonorrhoeae negative clinical samples were used to evaluate the cross-reactivity. Finally, the method was applied to 64 clinical samples to assess its performance. RESULTS: Using Sanger sequencing as a reference method, sequences recovered from amplicon sequencing had a base accuracy of over 99.5% and the AMR sites were correctly identified. The limit of detection (LOD) was lower than 31 copies/reaction. No significant cross-reactivity was observed. Furthermore, target genes were successfully recovered from 64 clinical samples including 9 urines, demonstrating this method could be used in different types of samples. For clinical samples, the results can be obtained within a time frame of 7 h 40 min to 10 h 40 min, while for isolates, the turnaround time was approximately 2 h shorter. CONCLUSIONS: This method can serve as a versatile and convenient culture-free diagnostic method with the advantages of high sensitivity and accuracy.

7.
J Mol Diagn ; 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32818599

RESUMO

Antimicrobial resistance in Neisseria gonorrhoeae persists as a major public health concern globally. We developed and evaluated a multiplex assay that relied on high-resolution melting (HRM) technology as a rapid, simple, and cost-effective method for simultaneously detecting and identifying different molecular markers associated with extended-spectrum cephalosporins (ESCs) and azithromycin (AZM) resistance in N. gonorrhoeae. Forty-eight well-characterized N. gonorrhoeae clinical isolates were selected for initial assay establishment. The multiplex HRM assays were able to accurately identify different nucleotide variations of the antimicrobial resistance determinants related to ESCs and AZM resistance. Specificity and cross-reactivity were assessed by testing 15 nongonococcal strains. Then, the assay was validated on 218 archived DNA specimens that had been sequenced using whole-genome sequencing technology. Compared with whole-genome sequencing, these assays had a sensitivity of 98.6%, with a specificity of 99.2%. For further validation of the assay's performance, a total of 338 samples (156 clinical isolates and 182 clinical specimens) were screened using the multiplex HRM assay. The results showed good concordance with the results of PCR sequencing. Given its rapidity (within 90 minutes), ease of performing, and low cost (<$1.00 per sample), this method may be applied to large-scale epidemiologic programs for increasing surveillance of ESCs and AZM resistance in N. gonorrhoeae.

8.
J Antimicrob Chemother ; 75(10): 2817-2825, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688393

RESUMO

BACKGROUND: Complicated mechanisms and variable determinants related to drug resistance pose a major challenge to obtain comprehensive antimicrobial resistance (AMR) profiles of Neisseria gonorrhoeae. Meanwhile, cephalosporin-resistant mosaic penA alleles have been reported worldwide. Therefore, it is urgent to monitor the expansion of cephalosporin-resistant mosaic penA alleles. OBJECTIVES: To develop a comprehensive high-throughput method to efficiently screen AMR determinants. METHODS: We developed a method based on multiplex PCR with MALDI-TOF MS, which can simultaneously screen for 24 mutations associated with multiple antimicrobial agents in 19 gonococcal AMR loci (NG-AMR-MS). The performance of the NG-AMR-MS method was assessed by testing 454 N. gonorrhoeae isolates with known MICs of six antibiotics, eight non-gonococcal Neisseria strains, 214 clinical samples and three plasmids with a confirmed mosaic penA allele. RESULTS: The results show that NG-AMR-MS had a specificity of 100% with a sensitivity as low as 10 copies per reaction (except for PorB A121D/N/G, 100 copies per reaction). For clinical samples with gonococcal load >5 copies/µL, the method can accurately identify 20 AMR mutations. In addition, the method successfully detected specific cephalosporin-resistant strains with the A311V mutation in the penA allele. CONCLUSIONS: Our high-throughput method can provide comprehensive AMR profiles within a multiplex format. Furthermore, the method can be directly applied to screening for AMR among clinical samples, serving as an effective tool for overall monitoring of N. gonorrhoeae AMR and also provides a powerful means to comprehensively improve the level of monitoring.


Assuntos
Farmacorresistência Bacteriana , Gonorreia , Neisseria gonorrhoeae , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana/efeitos dos fármacos , Gonorreia/tratamento farmacológico , Humanos , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/genética
9.
Sensors (Basel) ; 20(5)2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32155770

RESUMO

The low frequency magnetic field detection ability of magnetoresistive (MR)sensor is seriously affected by 1/f noise. At present, the method to suppress the influence of low frequency noise is mainly to modulate the measured magnetic field by mechanical resonance. In this paper, a novel modulation concept employing a magnetoelectric coupling effect is proposed. A design method of modulation structure based on an equivalent magnetic circuit model (EMCM) and a single domain model of in-plane moment was established. An EMCM was established to examine the relationship between the permeability of flux modulation film (FMF) and modulation efficiency, which was further verified through a finite element simulation model (FESM). Then, the permeability modulated by the voltage of a ferroelectric/ferromagnetic (FE/FM) multiferroic heterostructure was theoretically studied. Combining these studies, the modulation structure and the material were further optimized, and a FeSiBPC/PMN-PT sample was prepared. Experimental results show that the actual magnetic susceptibility modulation ability of FeSiBPC/PMN-PT reached 150 times, and is in good agreement with the theoretical prediction. A theoretical modulation efficiency higher than 73% driven by a voltage of 10 V in FeSiBPC/PMN-PT can be obtained. These studies show a new concept for magnetoelectric coupling application, and establish a new method for magnetic field modulation with a multiferroic heterostructure.

10.
J Antimicrob Chemother ; 75(4): 907-910, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31899504

RESUMO

OBJECTIVES: The continuous emergence of ceftriaxone-resistant Neisseria gonorrhoeae strains threatens the effectiveness of current treatment regimens for gonorrhoea. The objective of the present study was to characterize three ceftriaxone-resistant N. gonorrhoeae strains with a novel mosaic penA allele isolated in China. METHODS: Three ceftriaxone-resistant Neisseria gonorrhoeae strains (GC150, GC161 and GC208) isolated in 2017 were characterized by N. gonorrhoeae multiantigen sequence typing (NG-MAST), MLST and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR). Recombination analyses were performed using the SimPlot software. RESULTS: Three strains had the same antibiotic resistance profiles, with resistance to ceftriaxone (MIC 0.5 mg/L), ciprofloxacin (MIC 8.0 mg/L), penicillin (MIC 2.0 mg/L) and tetracycline (MIC 2.0-8.0 mg/L). STs were assigned as MLST7360, NG-MAST14292 and NG-STAR1611/NG-STAR1612. The penA gene of these three strains differed from previous ceftriaxone-resistant gonococcal strains and harboured a novel mosaic allele (penA-121.001). Like N. gonorrhoeae FC428, a widely disseminated ceftriaxone-resistant strain that was initially described in Japan in 2015, all strains also possessed substitutions A311V and T483S in PBP2, which are associated with resistance to ceftriaxone. Potential recombination events were detected in penA between N. gonorrhoeae strain FC428 and commensal Neisseria species. Our results provide further evidence that the commensal Neisseria species (Neisseria cinerea and Neisseria perflava) can serve as a reservoir of ceftriaxone resistance-mediating penA sequences in clinical gonococcal strains. CONCLUSIONS: The emergence of such strains may be the result of the interspecies recombination of penA genes between N. gonorrhoeae strain FC428 and commensal Neisseria species.


Assuntos
Gonorreia , Neisseria gonorrhoeae , Antibacterianos/farmacologia , Ceftriaxona/farmacologia , China , Humanos , Japão , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Neisseria , Neisseria gonorrhoeae/genética , Software
11.
J Antimicrob Chemother ; 75(1): 106-109, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31834402

RESUMO

OBJECTIVES: Increased awareness of the international spread of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone, which threatens recommended dual therapy, is essential. The objective of the present study was to develop and evaluate a rapid, simple and cost-effective method based on high-resolution melting (HRM) analysis for direct detection of the FC428 clone from clinical isolates and specimens. METHODS: The singleplex HRM assay was designed to identify the FC428 clone by using specific primers, which flank the alteration A311V in the penA-60.001 allele. Analytical performance was initially evaluated by testing 623 isolates and a panel of non-gonococcal strains. To ensure the method can be directly applied in clinical samples, two internal control targets (opa and porA) were also designed and included in the final multiplex HRM assay. Two hundred and eighty-two clinical samples (94 urine and 188 urethral/genital swabs) were then analysed using this multiplex HRM assay. RESULTS: The FC428 clone was easily differentiated from the non-mosaic alleles and other mosaic alleles without A311 mutations by comparing the differences in melt curves. Cross-reactivity was not observed for the penA-60.001 allele when testing 15 non-gonococcal Neisseria strains. When applied to the 623 isolates, the HRM assay successfully characterized one isolate as an FC428 clone (MLST1903, NG-MAST3435, NG-STAR233). Our data show that the multiplex HRM assay with high specificity can be directly applied in clinical samples. CONCLUSIONS: This method can generate results within 90 min at a cost of less than US$0.5 per isolate or sample, making this assay an ideal tool for large epidemiological studies to enhance surveillance of the internationally transmitted ceftriaxone-resistant N. gonorrhoeae FC428 clone.


Assuntos
Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/genética , Alelos , Saúde Global , Gonorreia/diagnóstico , Gonorreia/microbiologia , Gonorreia/transmissão , Humanos , Testes de Sensibilidade Microbiana , Sensibilidade e Especificidade , Temperatura de Transição
12.
Sci China Life Sci ; 63(7): 1063-1070, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31784935

RESUMO

Gonorrhea is one of the most common sexually transmitted diseases worldwide. To cure infection and prevent transmission, timely and appropriate antimicrobial therapy is necessary. Unfortunately, Neisseria gonorrhoeae, the etiological agent of gonorrhea, has acquired nearly all known mechanisms of antimicrobial resistance (AMR), thereby compromising the efficacy of antimicrobial therapy. Treatment failure resulting from AMR has become a global public health concern. Whole-genome sequencing is an effective method to determine the AMR characteristics of N. gonorrhoeae. Compared with next-generation sequencing, the MinION sequencer (Oxford Nanopore Technologies (ONT)) has the advantages of long read length and portability. Based on a pilot study using MinION to sequence the genome of N. gonorrhoeae, we optimized the workflow of sequencing and data analysis in the current study. Here we sequenced nine isolates within one flow cell using a multiplexed sequencing strategy. After hybrid assembly with Illumina reads, nine integral circular chromosomes were obtained. By using the online tool Pathogenwatch and a BLAST-based workflow, we acquired complete AMR profiles related to seven classes of antibiotics. We also evaluated the performance of ONT-only assemblies. Most AMR determinants identified by ONT-only assemblies were the same as those identified by hybrid assemblies. Moreover, one of the nine assemblies indicated a potentially novel antimicrobial-related mutation located in mtrR which results in a frame-shift, premature stop codon, and truncated peptide. In addition, this is the first study using the MinION sequencer to obtain complete genome sequences of N. gonorrhoeae strains which are epidemic in China. This study shows that complete genome sequences and antimicrobial characteristics of N. gonorrhoeae can be obtained using the MinION sequencer in a simple and cost-effective manner, with hardly any knowledge of bioinformatics required. More importantly, this strategy provides us with a potential approach to discover new AMR determinants.


Assuntos
Antibacterianos/metabolismo , Genoma Bacteriano/genética , Neisseria gonorrhoeae/genética , Biologia Computacional , Análise Mutacional de DNA , DNA Bacteriano/análise , Farmacorresistência Bacteriana , Biblioteca Gênica , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , Nanoporos , Sequenciamento Completo do Genoma
13.
Infect Drug Resist ; 12: 3739-3743, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31819556

RESUMO

Unbiased metagenomic next-generation sequencing (mNGS) has been widely applied in clinical microbiology for infectious disease diagnostics. Some successful applications in central nervous system infections and respiratory tract infections have proved it to be a promising tool for pathogen detection. Here, mNGS was used to confirm the infectious etiology in a case of tuberculous coxitis, which is a common type of extrapulmonary tuberculosis (TB). A 77-year-old Asian male presented with hip pain and fever was diagnosed with smear- and culture-negative tuberculous coxitis based on the evidence of imaging and interferon-γ release assay. At the same time as the anti-TB therapy started, the patient underwent joint clearance surgery. Whole blood and synovial fluid sampled from surgery were kept for bacteriological confirmation using mNGS with high sequencing depth. However, only two paired-end reads from synovial fluid samples were identified as Mycobacterium tuberculosis. Before leaving hospital, the patient was still receiving anti-TB treatment and began to recover. Considering the obvious escalation of the cost and analysis time as the depth of sequencing increases, although we got a positive result here, the scarce number of reads obtained through ultra-deep sequencing indicates its limitations in extrapulmonary tuberculosis.

14.
Infect Drug Resist ; 12: 2671-2682, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695443

RESUMO

Purpose: Sexually transmitted infections (STIs), representing a major global health problem, are caused by different microbes, including bacteria, viruses, and protozoa. Unfortunately, infections of different sexually transmitted pathogens often present similar clinical symptoms, so it is almost impossible to distinguish them clinically. Therefore, the aim of the current study was to develop a sensitive, multitarget, and high-throughput method that can detect various agents responsible for STIs. Methods: We developed and tested a 23-plex PCR coupled with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) assay (sexually transmitted infection-mass spectrometry, STI-MS) that simultaneously targets 11 different agents, including 8 most common clinical pathogens related to STIs (HSV-1, HSV-2, Neisseria gonorrhoeae , Chlamydia trachomatis, Treponema pallidum, Trichomonas vaginalis, Mycoplasma genitalium, and Haemophilus ducreyi) and 3 controversial microorganisms as pathogens (Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum). Results: The results showed that the STI-MS approach can accurately detect the expected agents, without cross-reaction with other organisms. The limit of detection of each STI-MS assay was ranged from 1.739 to 10.009 copies/reaction, using probit analyses. The verification rate for each target organism of the STI-MS ranged from a minimum of 89.3% to a maximum of 100%, using conventional assays and ultrasensitive digital PCR to confirm the STI-MS-positive results. To further evaluate the clinical performance of this assay, 241 clinical specimens (124 urethral/cervical swabs and 117 urine) were tested in parallel using the STI-MS assay and monoplex real-time PCR for each agent. The overall validation parameters of STI-MS were extremely high including sensitivity (from 85.7% to 100%), specificity (from 92.3% to 100%), PPV (from 50% to 100%), and NPV (from 99.1% to 100%) for each target. Conclusion: STI-MS is a useful high-throughput screening tool for detecting mixed infections of STIs and has great potential for application in large-scale epidemiological programs for specific microorganisms of STI.

15.
Sensors (Basel) ; 19(20)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31619009

RESUMO

To improve the sensitivity of the magnetic tunnel junction(MTJ)sensor, a novel architecture for a double-gap magnetic flux concentrator (MFC) was studied theoretically and experimentally in this paper. The three-dimensional finite element model of magnetic flux was established to optimize the magnetic field amplification factor, with different gaps. The simulation results indicate that the sensitivity of an MTJ sensor with a double-gap MFC can be significantly better than that of a sensor with a traditional single-gap MFC, due to the fact that the magnetic magnification sharply increases with the decrease in effective gap width. Besides this, the half-bridge MTJ sensors with the double-gap MFC were fabricated using photolithography, ion milling, evaporation, and electroplating processes. Experimental results show that the sensitivity of the MTJ sensor increased by ten times compared to the sensor without the double-gap MFC, which underlines the theoretical predictions. Furthermore, there is no significant increase in the sensor noise. The work in this paper contributes to the development of high-performance MTJ sensors.

16.
Emerg Microbes Infect ; 8(1): 1546-1549, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31661379

RESUMO

The growing multidrug-resistant Neisseria gonorrhoeae is a serious global threat to gonococcal therapy. During 2017-2018, we identified a rare multidrug-resistant (ceftriaxone and azithromycin) strain (GC250) and four strains (GC185, GC195, GC196 and GC249) with both resistance to ceftriaxone and decreased susceptibility to azithromycin. All strains belonged to NG-STAR ST1143, including the mosaic penA-60.001, which is closely related to ceftriaxone resistance. The characterization of antimicrobial resistance (AMR) determinants and phylogenetic analysis showed these five strains were closely related to internationally spreading ceftriaxone-resistant N. gonorrhoeae FC428, but with higher azithromycin MIC. Findings here demonstrated that this clone not only initiated clonal expansion in China, but acquired azithromycin resistance.


Assuntos
Antibacterianos/farmacologia , Azitromicina/farmacologia , Ceftriaxona/farmacologia , Farmacorresistência Bacteriana Múltipla , Gonorreia/microbiologia , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/isolamento & purificação , China , Feminino , Heterossexualidade , Humanos , Masculino , Testes de Sensibilidade Microbiana , Neisseria gonorrhoeae/classificação , Neisseria gonorrhoeae/genética , Filogenia
17.
Onco Targets Ther ; 12: 5779-5791, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31410023

RESUMO

Background: There is no guideline recommendation for preventing hepatocellular carcinoma (HCC) recurrence after hepatic resection. Moreover, an unmet need exists on the effectiveness of sorafenib therapy in recurrent HCC. Purpose: We therefore assessed the efficacy and safety of sorafenib in Chinese HCC patients with high risk of recurrence. Patients and methods: Data were collected retrospectively from 15 Chinese research centers from January 1, 2012 to November 15, 2013, by chart reviews of patients with moderate-advanced HCC who received hepatic carcinectomy. The primary end point was recurrence-free survival rate at 1 year in patients with a high recurrence risk. Secondary end points included 1-year survival rate, time to recurrence and safety assessment. Results: A total of 209 high-risk patients (sorafenib, n=98; control, n=111) who underwent carcinectomy were analyzed. There was no significant difference in the proportion of patients with recurrence-free survival at 1 year between the sorafenib and control (70.43% vs 68.90%: χ2=0.007, P=0.934). One-year survival rate was significantly higher with sorafenib than observed with control (95.5% vs 83.35%; χ2=7.441, P=0.006). Time to recurrence between sorafenib and control groups was similar. Incidences of all the adverse events (AEs) were similar in both the groups and transaminase elevation was most common in both groups (20.37% vs 24.79%). Thrombocytopenia incidence was significantly lower with the sorafenib group than with control (1.85% vs 9.40%; P=0.015). Conclusion: Sorafenib may be considered as a feasible option in the treatment of HCC recurrence.

18.
EClinicalMedicine ; 7: 47-54, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31193648

RESUMO

Background: Tracking the spread of the Neisseria gonorrhoeae strains with decreased susceptibility or resistance to cephalosporins is a major priority for global surveillance programmes. Whole-genome sequencing (WGS) has been widely used by increasing countries in North America, Europe, and Pacific to determine the decreased susceptible or resistance determinants of Neisseria gonorrhoeae, track the spread of these determinants throughout the gonococcal population at national or regional level. However, no studies to date have examined the genomic epidemiology of gonorrhea in Asia where the antimicrobial resistant strains of Neisseria gonorrhoeae appears to have emerged before disseminating the strains globally. Methods: We obtained clinical isolates and data from the China Gonococcal Resistance Surveillance Programme (China-GRSP) from 2012 to 2013. We sequenced the genomes of 435 clinical isolates of Neisseria gonorrhoeae, including 112 (25.6%) isolates with decreased susceptibility to ceftriaxone (Cfx-DS). We assessed the association between antimicrobial resistance genotype and phenotype. We also compared our data with the whole genome data of the isolates from the USA and the UK in the GenBank. Findings: The most prevalent MLST STs in our gonococcal population were MLST ST7827 (n = 74), followed by ST7365 (n = 58), ST1600 (n = 38), ST7367 (n = 35), and ST7363 (n = 29). MLST ST1901 which was reported as the predominant ST in the US was not found in our population. A total of 2512 strains, including additional 2077 published NG strains, were further included for phylogenetic analysis. It generated two distinct lineages - lineage 1 and lineage 2. Analysis of MLST ST1901 in the database indicate that most of MLST ST1901 isolates in the lineage2.6 were Cfx-DS isolates while all isolates in the lineage 2.1 were sensitive to ceftriaxone (77/110 vs. 0/13; p < 0.001). ST1901/lineage 2.6 is a ceftriaxone resistant clone which cannot distinguished by MLST genotyping. In the isolates from our study, the MICs of ceftriaxone for ST7363/lineage 2.6 isolates ranged from 0.008-0.125 mg/L (mean ±â€¯SD; 0.054 ±â€¯0.043 mg/L) while those for ST7363/lineage 2.8 isolates ranged from 0.032-0.250 mg/L (0.134 ±â€¯0.085 mg/L). All ST7363/lineage 2.8 isolates contained penA mosaic alleles. Interpretation: To our knowledge, current study is the first WGS-based analysis of gonococcal population at national level in Asia. China harbors the different predominant clones associated with decreased susceptibility to ceftriaxone from those clones circulated in other regions. The findings from the study can be not only used as baseline data for future studies in China but also contributable to our understanding on spread of N. gonorrhoeae and its resistant strains at regional and global levels. Funding: The Chinese Academy Medical Sciences (CAMS) Initiative for Innovative Medicine.

19.
Sci Adv ; 5(5): eaaw3988, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31114808

RESUMO

The surface of a three-dimensional topological insulator (TI) hosts two-dimensional massless Dirac fermions (DFs), the gapless and spin-helical nature of which leads to their high transmission through surface defects or potential barriers. Here, we report the behaviors of topological surface states (TSS) in a triangular quantum corral (TQC) which, unlike a circular corral, is supposed to be totally transparent for DFs. By real-space mapping of the electronic structure of TQCs, both the trapping and detrapping behaviors of the TSS are observed. The selection rules are found to be governed by the geometry and spin texture of the constant energy contour of TSS upon the strong hexagonal warping in Bi2Te3. Our work indicates the extended nature of TSS and elucidates the selection rules of the trapping of TSS in the presence of a complicated surface state structure, giving insights into the effective engineering of DFs in TIs.

20.
Front Physiol ; 9: 1181, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30233388

RESUMO

Reference values on atrial and ventricular strain from cardiovascular magnetic resonance (CMR) are essential in identifying patients with impaired atrial and ventricular function. However, reference values have not been established for Chinese subjects. One hundred and fifty healthy volunteers (75 Males/75 Females; 18-82 years) were recruited. All underwent CMR scans with images acceptable for further strain analysis. Subjects were stratified by age: Group 1, 18-44 years; Group 2, 45-59 years; Group 3, ≥60 years. Feature tracking of CMR cine imaging was used to obtain left atrial global longitudinal (LA Ell) and circumferential strains (LA Ecc) and respective systolic strain rates, left ventricular longitudinal (LV Ell), circumferential (LV Ecc) and radial strains (LV Err) and their respective strain rates, and right ventricular longitudinal strain (RV Ell) and strain rate. LA Ell and LA Ecc were 32.8 ± 9.2% and 40.3 ± 13.4%, respectively, and RV Ell was -29.3 ± 6.0%. LV Ell, LV Ecc and LV Err were -22.4 ± 2.9%, -24.3 ± 3.1%, and 79.0 ± 19.4%, respectively. LV Ell and LV Ecc were higher in females than males (P < 0.05). LA Ell, LA Ecc, and LV Ecc decreased, while LV Err increased with age (P < 0.05). LV Ell and RV Ell were not shown to be associated with age. Normal ranges for atrial and ventricular strain and strain rates are provided using CMR feature tracking in Chinese subjects.

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