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The highly mutated and transmissible Omicron variant has provoked serious concerns over its decreased sensitivity to the current coronavirus disease 2019 (COVID-19) vaccines and evasion from most anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (NAbs). In this study, we explored the possibility of combatting the Omicron variant by constructing bispecific antibodies based on non-Omicron NAbs. We engineered ten IgG-like bispecific antibodies with non-Omicron NAbs named GW01, 16L9, 4L12, and REGN10987 by fusing the single-chain variable fragments (scFvs) of two antibodies through a linker and then connecting them to the Fc region of IgG1. Surprisingly, eight out of ten bispecific antibodies showed high binding affinity to the Omicron receptor-binding domain (RBD) and exhibited extreme breadth and potency against pseudotyped SARS-CoV-2 variants of concern (VOCs) including Omicron, as well as authentic Omicron(+R346K) variants. Six bispecific antibodies containing the cross-NAb GW01 neutralized Omicron variant and retained their abilities to neutralize other sarbecoviruses. Bispecific antibodies inhibited Omicron infection by binding to the ACE2 binding site. A cryo-electron microscopy (cryo-EM) structure study of the representative bispecific antibody FD01 in complex with the Omicron spike (S) revealed 5 distinct trimers and one unique bi-trimer conformation. The structure and mapping analyses of 34 Omicron S variant single mutants elucidated that two scFvs of the bispecific antibody synergistically induced the RBD-down conformation into 3-RBD-up conformation, enlarged the interface area, accommodated the S371L mutation, improved the affinity between a single IgG and the Omicron RBD, and hindered ACE2 binding by forming bi-trimer conformation. Our study offers an important foundation for anti-Omicron NAb design. Engineering bispecific antibodies based on non-Omicron NAbs may provide an efficient solution to combat the Omicron variant.
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In spite of the successful development of effective countermeasures against Covid-19, variants have and will continue to emerge that could compromise the efficacy of currently approved neutralizing antibodies and vaccines. Consequently, novel and more efficacious agents are urgently needed. We have developed a bispecific antibody, 2022, consisting of two antibodies, 2F8 and VHH18. 2F8 was isolated from our proprietary fully synthetic human IDEAL (Intelligently Designed and Engineered Antibody Library)-VH/VL library and VHH18 is a single domain antibody isolated from IDEAL-nanobody library. 2022 was constructed by attaching VHH18 to the C-terminal of Fc of 2F8. 2022 binds two non-overlapping epitopes simultaneously on the RBD of the SARS-CoV-2 spike protein and blocks the binding of RBD to human angiotensin-converting enzyme 2 (ACE2). 2022 potently neutralizes SARS-CoV-2 and all of the variants tested in both pseudovirus and live virus assays, including variants carrying mutations known to resist neutralizing antibodies approved under EUA and that reduce the protection efficiency of current effective vaccines. The half-maximum inhibitory concentration (IC50) of 2022 is 270 pM, 30 pM, 20 pM, and 1 pM, for wild-type, alpha, beta, and delta pseudovirus, respectively. In the live virus assay, 2022 has an IC50 of 26.4 pM, 13.3 pM, and 88.6 pM, for wild-type, beta, and delta live virus, respectively. In a mouse model of SARS-CoV-2, 2022 showed strong prophylactic and therapeutic effects. A single administration of 2022 intranasal (i.n.) or intraperitoneal (i.p.) 24 hours before virus challenge completely protected all mice from bodyweight loss, as compared with up to 20% loss of bodyweight in placebo treated mice. In addition, the lung viral titers were undetectable (FRNT assay) in all mice treated with 2022 either prophylactically or therapeutically, as compared with around 1x105 pfu/g lung tissue in placebo treated mice. In summary, bispecific antibody 2022 showed potent binding and neutralizing activity across a variety of SARS-CoV-2 variants and could be an attractive weapon to combat the ongoing waves of the COVID-19 pandemic propagated mainly by variants, especially, the much more contagious delta variant.
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COVID-19 is a huge threat to global health. Due to the lack of definitive etiological therapeutics currently, effective disease monitoring is of high clinical value for better healthcare and management of the large number of COVID-19 patients. In this study, we recruited 37 COVID-19 patients, collected 176 blood samples upon diagnosis and during treatment, and analyzed cell-free DNA (cfDNA) in these samples. We report gross abnormalities in cfDNA of COVID-19 patients, including elevated GC content, altered molecule size and end motif patterns. More importantly, such cfDNA characteristics reflect patient-specific physiological conditions during treatment. Further analysis on tissue origin tracing of cfDNA reveals frequent tissue injuries in COVID-19 patients, which is supported by clinical diagnoses. Hence, we demonstrate the translational merit of cfDNA as valuable analyte for effective disease monitoring, as well as tissue injury assessment in COVID-19 patients.
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OBJECTIVE:To optimize the honey-stir-fried technology of Chelidonium majus . METHODS :Taking the mass ratio of water to honey ,the ratio of honey water to C. majus ,stir-fired temperature ,stir-fired time as the factors ,the total contents of chelidonine ,coptisine hydrochloride ,sanguinarine,berberine,chelerythrine as response values ,Box-Behnken response surface method was used to optimize the processing technology ,and valifation test was conducted. RESULTS :The optimum process conditions were as follows the ratio of water to refined honey 1∶1.9(g/g),the ratio of honey water to C. majus 21∶100(g/g), stir-fried temperature 122 ℃,stir-fried time 10.40 min. After 3 times of validation ,average total contents of 5 components was 10.37 mg/g(RSD=0.23%),relative error of which with predicted value (10.39 mg/g)was 0.19%. CONCLUSIONS :The optimized honey-stir-fried technology of C. majus is stable and feasible.
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BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of Coronavirus disease 2019 (COVID-19). However, microbial composition of the respiratory tract and other infected tissues, as well as their possible pathogenic contributions to varying degrees of disease severity in COVID-19 patients remain unclear. MethodBetween January 27 and February 26, 2020, serial clinical specimens (sputum, nasal and throat swab, anal swab and feces) were collected from a cohort of hospitalized COVID-19 patients, including 8 mildly and 15 severely ill patients (requiring ICU admission and mechanical ventilation), in the Guangdong province, China. Total RNA was extracted and ultra-deep metatranscriptomic sequencing was performed in combination with laboratory diagnostic assays. Co-infection rates, the prevalence and abundance of microbial communities in these COVID-19 patients were determined. FindingsNotably, respiratory microbial co-infections were exclusively found in 84.6% of severely ill patients (11/13), among which viral and bacterial co-infections were detected by sequencing in 30.8% (4/13) and 69.2% (9/13) of the patients, respectively. In addition, for 23.1% (3/13) of the patients, bacterial co-infections with Burkholderia cepacia complex (BCC) and Staphylococcus epidermidis were also confirmed by bacterial culture. Further, a time-dependent, secondary infection of B. cenocepacia with expressions of multiple virulence genes in one severely ill patient was demonstrated, which might be the primary cause of his disease deterioration and death one month after ICU admission. InterpretationOur findings identified distinct patterns of co-infections with SARS-CoV-2 and various respiratory pathogenic microbes in hospitalized COVID-19 patients in relation to disease severity. Detection and tracking of BCC-associated nosocomial infections are recommended to improve the pre-emptive treatment regimen and reduce fatal outcomes of hospitalized patients infected with SARS-CoV-2. FundingNational Science and Technology Major Project of China, National Major Project for Control and Prevention of Infectious Disease in China, the emergency grants for prevention and control of SARS-CoV-2 of Ministry of Science and Technology and Guangdong province, Guangdong Provincial Key Laboratory of Genome Read and Write, Guangdong Provincial Academician Workstation of BGI Synthetic Genomics, and Shenzhen Engineering Laboratory for Innovative Molecular Diagnostics.
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The emergence of the novel human coronavirus, SARS-CoV-2, causes a global COVID-19 (coronavirus disease 2019) pandemic. Here, we have characterized and compared viral populations of SARS-CoV-2 among COVID-19 patients within and across households. Our work showed an active viral replication activity in the human respiratory tract and the co-existence of genetically distinct viruses within the same host. The inter-host comparison among viral populations further revealed a narrow transmission bottleneck between patients from the same households, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Author summaryIn this study, we compared SARS-CoV-2 populations of 13 Chinese COVID-19 patients. Those viral populations contained a considerable proportion of viral sub-genomic messenger RNAs (sgmRNA), reflecting an active viral replication activity in the respiratory tract tissues. The comparison of 66 identified intra-host variants further showed a low viral genetic distance between intra-household patients and a narrow transmission bottleneck size. Despite the co-existence of genetically distinct viruses within the same host, most intra-host minor variants were not shared between transmission pairs, suggesting a dominated role of stochastic dynamics in both inter-host and intra-host evolutions. Furthermore, the narrow bottleneck and active viral activity in the respiratory tract show that the passage of a small number of virions can cause infection. Our data have therefore delivered a key genomic resource for the SARS-CoV-2 transmission research and enhanced our understanding of the evolutionary dynamics of SARS-CoV-2.
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As of middle May 2020, the causative agent of COVID-19, SARS-CoV-2, has infected over 4 million people with more than 300 thousand death as official reports1,2. The key to understanding the biology and virus-host interactions of SARS-CoV-2 requires the knowledge of mutation and evolution of this virus at both inter- and intra-host levels. However, despite quite a few polymorphic sites identified among SARS-CoV-2 populations, intra-host variant spectra and their evolutionary dynamics remain mostly unknown. Here, using deep sequencing data, we achieved and characterized consensus genomes and intra-host genomic variants from 32 serial samples collected from eight patients with COVID-19. The 32 consensus genomes revealed the coexistence of different genotypes within the same patient. We further identified 40 intra-host single nucleotide variants (iSNVs). Most (30/40) iSNVs presented in single patient, while ten iSNVs were found in at least two patients or identical to consensus variants. Comparison of allele frequencies of the iSNVs revealed genetic divergence between intra-host populations of the respiratory tract (RT) and gastrointestinal tract (GIT), mostly driven by bottleneck events among intra-host transmissions. Nonetheless, we observed a maintained viral genetic diversity within GIT, showing an increased population with accumulated mutations developed in the tissue-specific environments. The iSNVs identified here not only show spatial divergence of intra-host viral populations, but also provide new insights into the complex virus-host interactions.
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COVID-19 has caused a major epidemic worldwide, however, much is yet to be known about the epidemiology and evolution of the virus. One reason is that the challenges underneath sequencing HCoV-19 directly from clinical samples have not been completely tackled. Here we illustrate the application of amplicon and hybrid capture (capture)-based sequencing, as well as ultra-high-throughput metatranscriptomic (meta) sequencing in retrieving complete genomes, inter-individual and intra-individual variations of HCoV-19 from clinical samples covering a range of sample types and viral load. We also examine and compare the bias, sensitivity, accuracy, and other characteristics of these approaches in a comprehensive manner. This is, to date, the first work systematically implements amplicon and capture approaches in sequencing HCoV-19, as well as the first comparative study across methods. Our work offers practical solutions for genome sequencing and analyses of HCoV-19 and other emerging viruses.
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Objective The aim of this study was to investigate the role and mechanism of ABL2 in lung cancer and its mech-anism. Methods The expression of ABL2 in lung cancer and adjacent tissues was detected by Real-Time PCR. A lung adenocarci-noma A549 cell line stably expressing of ABL2 was established,and the changes of cell proliferation and migration ability were detec-ted by MTT,cell migration and colony formation assays. Western blot was used to detect the expression of EMT,apoptosis and PI3K/AKT signaling pathway-related proteins. Results The expression of ABL2 in lung cancer tissues was significantly higher than that in adjacent tissues(P<0. 001). After silencing ABL2 in the A549 cells,compared with the control group,the migration ability of cells was weakened after 48 hours(P<0. 001),the growth rate of cells began to slow down from the third day(P<0. 05),and the average number of clones formed after 15 days also decreased(P<0. 01). The expression of E-cadherin( P<0. 001) was increased in the epithelial cell marker after silencing ABL2,and the expression of stromal cell markers N -cadherin ( P <0. 001),Vimentin ( P <0. 01)and Snail(P<0. 001)was decreased. The expression of apoptosis-related protein Bcl-XL(P<0. 01)was decreased and BAX ( P<0. 001)expression was up-regulated. The expression of PI3K/AKT signaling pathway-associated proteins such as PI3K P110 (P<0. 05),AKT(P<0. 01) and p-AKT( P<0. 05) was significantly decreased. Conclusion Silencing ABL2 gene can promote apoptosis,and inhibit proliferation and migration of lung cancer cells through a PI3K/AKT signaling pathway.
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Objective To develop a set of high-frequency ultrasound grayscale blood flow imaging system based on field programmable gate array (FPGA) to execute simultaneous imaging of superficial blood flow and tissues.Methods This system was mainly composed of an ultrasonic transducer,an ultrasonic transmission and receiving modules,imaging software in host computer and peripheral equipment.A PVDF transducer with the frequency between 20 and 50 MHz was used for the ultrasonic transducer.In transmission and receiving modules,the radio frequency echo signals were digitized by high-speed A/D.Then the digital signals were transmitted,added,filtered,demodulated,log amplified,double sampled,and lastly transferred to the host computer by USB interface for real-time display.Results A vascular 1 mm far form the surface of the hand skin was examined by this system.Four blood flow images were obtained in corresponding with four transmission frequencies.Conclusion Real-time superficial organ blood flow imaging is realized by this system.The solution has the architecture concise and clear,and lays an experimental foundationfor high-frequency ultrasound gray-scale blood flow imaging.
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Objective To investigate the correlations of Eotaxin-1,rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody with the activity of rheumatoid arthritis (RA).Methods A total of 58 patients with early RA,46 patients without RA and 53 healthy controls from our hospital during December 2014 and December 2015 were enrolled in our study.The activity of RA was evaluated by the swollen joint count (SJC),tender joint count (TJC) and DAS28 score.The levels of serum Eotaxin-1 and antiCCP antibody were detected by ELISA and serum RF levels were determined by the immunological turbidimetry.The comparisons of serum Eotaxin-1,anti-CCP antibody and RF levels between different groups were performed with ANOVA and their correlations with SJC,TJC and DAS28 score were analyzed by Spearman rank correlation.Results The levels of Eotaxin-1,anti-CCP antibody and RF in RA patients were (96.02 ± 2 1.07) pg/mL,(183.42 ± 87.45) U/mL and (119.09 ± 62.30) RU/mL,respectively,which were significantly higher than those in the patients without RA and healthy controls (P < 0.01).The levels of serum Eotaxin-1 in RA patients were significantly related to TJC,SJC and DAS28 score (P < 0.01),while the levels of anti-CCP antibody were related to TJC and DAS28 score.The levels of RF were only related to DAS28 score.Conclusion The levels of serum Eotaxin-1 and anti-CCP antibody in RA patients are significantly correlated with the activity of RA,which may be new serum markers to monitor the activity of RA.
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Objective Speckle is the inherent problem exists in B-Mode ultrasound image,and effective speckle noise reduction will improve the image quality and contribute greatly to clinical doctors to diagnose,especially in fine ophthalmic examination with high frequency ultrasound.Methods This paper proposed a new speckle reduction method based on the Laplacian pyramid and multiscale analysis.In the Laplacian pyramid,true clinical features were separated from noise,according to the different bandpass ultrasound image characteristics in each layer,and the advanced eight directions speckle reduction anisotropic diffusion (SRAD)was adapted to suppressed the speckle noise,and the identified noise and the extracted features were selectively emphasized by suitable edge,coherence and contrast enhancement filtering from fine to coarse scales.The performance of the proposed method was compared to the traditional SRAD method and coherence-enhancing diffusion method by measuring the equivalent number of looks (ENL) and Time cost.Results The ENL and Time cost value of the proposed method were higher compared to the SRAD and the cedif method,i.e 1.172 3 vs 1.122 3,0.929 3 and 0.864 0 vs 1.396 0,1.468 3.Conclusions In summary,the proposed method can more effectively remove the speckle noise while preserving the edge and details of the images.
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To investigate the genetic character and origin of the first imported infection case of middle East respiratory syndrome coronavirus (named as MERS-CoV_China GD01), RNA was extracted from swabs of this patient followed by RT-PCR amplification. All coding gene of structural (S, E, M, E) and accessory (ORF3, ORF4a, ORF4b, ORF5, ORF8b) proteins were sequenced and analyzed. Phylogenetic analyses of structural protein coding genes of MERS-CoV_ China GD01 indicates that several substitutes exists in S coding gene and its origin belong group 5 of MERS-CoV, which were recent circulated in Saudi Arabia area, while other three structural genes (N, E, M) were very conserved. Phylogenetic analyses of accessory protein coding genes of MERS-CoV China GD01 indicates that several substitutes exists among ORF3, ORF4a, ORF4b and ORF5, while ORF8b was conserved. In conclusion, genome of MERS-CoV_ China GD01 was general conserved although several genetic variations were found among structural and accessory protein coding genes. This is the first report on sequencing and phylogenetic analyses of the first imported MERS case in China, which may pay the way for prevention and control of imported MERS-CoV infection.
Subject(s)
Humans , China , Conserved Sequence , Coronavirus Infections , Virology , Evolution, Molecular , Genomics , Middle East Respiratory Syndrome Coronavirus , Genetics , Physiology , Phylogeny , Sequence Analysis , Viral Proteins , GeneticsABSTRACT
A simple, rapid and sensitive colorimetric reverse-transcription loop-mediated isothermal amplification (RT-LAMP) was developed for rapid detection of Middle East respiratory syndrome coronavirus (MERS-CoV). The method employed six primers that recognized sequences of a nucleocapsid gene for amplification of nucleic acids under isothermal conditions at 63 degrees C for 60 min. Products were detected through a LA-320c Loopamp Turbidimeter (real-time RT-LAMP) or visual inspection of color change by pre-addition of Hydroxynaphthol Blue dye (visual RT-LAMP). Specificity of RT-LAMP was validated by detection of several human coronaviruses and common respiratory viruses. MERS-CoV real-time RT-LAMP had a linear correlation (R2) of 0.995 at 10(3)-10(6) copies. The limit of detection of real-time RT-LAMP, visual RT-LAMP and quantitative real-time PCR was 500, 1000 and 100 copies/reaction, respectively. The established RT-LAMP assay was demonstrated to be a rapid screening tool for MERS-CoV infection, and could be suitable in resource-limited clinical sites and for field studies.
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Humans , Coronavirus Infections , Virology , DNA Primers , Genetics , Middle East Respiratory Syndrome Coronavirus , Classification , Genetics , Nucleic Acid Amplification Techniques , Methods , Reverse TranscriptionABSTRACT
Objective:To deteat N‐terminal pro B type natriuretic peptide (NT‐pro BNP) and cystatin C (Cys C) con‐tent in Kazak patients with hypertensive heart disease (HHD) complicated heart failure (HF) and analyze the corre‐lation between them .Methods :A total of 100 Kazak HHD patients were divided into hypertension complicated HF group (Complicated HF group , n=50) and pure HHD group (n=50) .Venous blood sample was taken within 24h after hospitalization for measuring serum levels of NT‐proBNP and Cys C ,then they were compared and analyzed between two groups .Results:Compared with pure HHD group ,there were significant rise in serum levels of NT‐proBNP [ (246.53 ± 165.65) ng/L vs .(4568.32 ± 2722.36) ng/L] and Cys C [ (0.82 ± 0.31) mg/L vs .(1.93 ± 2.46) mg/L] in complicated HF group , P< 0.01 both .Spearman correlation analysis indicated that serum NT‐proBNP level was positively correlated with Cys C level in complicated HF group , r=0.961 , P<0.01. Conclusion:In Kazak patients with hypertensive heart disease complicated HF ,serum NT‐proBNP and Cys C levels significantly rise and they significantly positively correlate ,so it suggest there may be slight damaged renal function also .
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Objective To evaluate the effect of resistance training on glucolipid metabolism in a population with pre-diabetic metabolism (PDM).Methods Sixty persons with PDM were randomly divided into a resistance training group,an aerobic training group and a control group,each of 20 members.The exercise intervention groups exercised 3 times a week for 12 weeks in accordance with the exercise prescription,while the control group was without any regular aerobic exercise or resistance training.Before and after the 3 months of exercise training,fasting blood glucose (FBG),2 hours postpradial blood glucose (PBG),HbAlc,and lipid profile were tested.Body mass index (BMI),waistline,and blood pressure were also measured.Results Before the intervention,there were no significant differences in any of the average values among the 3 groups.In the resistance group,the average FBS (5.52 ± 0.52 mmol/L),HbA1 c (5.92 ± 0.36%) and TG (1.65 ± 0.92 mmol/L) had all decreased significantly after the training.In the aerobic group the average waistline,dilated blood pressure,FBG and HbAlc had decreased significantly.In the control group the average 2hrs PBG and LDL-C had both increased significantly compared to 3 months earlier.Compared with the resistance group,the average 2hrs PBGs were significantly higher in both the aerobic and control groups after the training.Moreover,compared with the aerobic group,the value in the control group was also significantly higher.Conclusion Both resistance training and aerobic exercise can lower fasting blood glucose and HbA1 c in PDM patients without obvious effect on BMI or low density lipoprotein level.Compared with aerobic exercises,resistance training had significant advantages in decreasing 2-hour postprandial blood glucose.
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<p><b>OBJECTIVE</b>To design and improve signal processing algorithms of ophthalmic ultrasonography based on FPGA.</p><p><b>METHODS</b>Achieved three signal processing modules: full parallel distributed dynamic filter, digital quadrature demodulation, logarithmic compression, using Verilog HDL hardware language in Quartus II.</p><p><b>RESULTS</b>Compared to the original system, the hardware cost is reduced, the whole image shows clearer and more information of the deep eyeball contained in the image, the depth of detection increases from 5 cm to 6 cm.</p><p><b>CONCLUSION</b>The new algorithms meet the design requirements and achieve the system's optimization that they can effectively improve the image quality of existing equipment.</p>
Subject(s)
Algorithms , Data Compression , Diagnostic Imaging , Ophthalmology , Signal Processing, Computer-Assisted , UltrasonographyABSTRACT
Objective To express the N protein of middle east respiratory syndrome coronavirus ( MERS-CoV) in prokaryotic expression system and evaluate the immunogenicity of the purified recombinant N protein.Methods The gene encoding N protein of MERS-CoV was synthesized and cloned into the vector pET30a to construct the recombinant expression plasmid pET30a-MERS-CoV-N.The transformed E.coli BL21 ( DE3) strains carrying expression plasmid were induced by IPTG to express N protein.The expressed protein was purified by using affinity chromatography.SDS-PAGE and Western blot assays were used to iden-tify the expressed N protein and evaluate its immunogenicity.Results The recombinant N protein was suc-cessfully expressed in soluble form with the size of 46×103 .The results of Western blot assay showed that the recombinant N protein could specifically react with rabbit serum samples positive for antibodies against N protein B-cell epitope peptide and mouse anti-His tag antibodies.No positive band against N protein was found when primary antibody was used with thirty adult serum samples from Beijing in 2008.Conclusion N protein of MERS-CoV was successfully expressed in prokaryotic expression system.The successful expres-sion of N protein laid the foundation for immunological diagnosis of N protein of MERS-CoV and researches on its immunogenicity.
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Objective To design phacoemulsification handpiece with small size and high amplitude amplification coefficient.Methods By introducing the electro-mechanical vibration characteristics of piezoelectric transducer and ultrasonic horn,and adopting the equivalent circuit method and analytical method,respectively,the size of the ultrasonic horn,quarter wavelength piezoelectric transducer and ultrasonic horn were designed.Then,modal and harmonic analysis in finite element analysis software ANSYS11.0 were used to simulate the handpiece,and to optimize the size of the handpiece after adding on needle.Results The results indicated that the longitudinal vibration frequency and amplification coefficient were very close to theoretical design.The errors were 1.4% and 5.8%,respectively.When piezoelectric ceramics were loaded with 300 V sinusoidal voltage,the displacement amplitude at the end of the needle reached 125.5 μm,which could meet the phacoemulsification surgery needs.Conclusion This design greatly reduced the size of the handpiece,and obtained high amplitude amplification coefficient.The simulation results sufficiently validated the theoretical design.
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<p><b>OBJECTIVE</b>Developing a high-frequency ultrasonic skin imaging system to obtain the high resolution ultrasonic image of the skin. And further analyzing the ultrasonic images of skin to explore the imaging characteristics of skin structure and then explore the value of high-frequency imaging in the application of skin diagnosis.</p><p><b>METHODS</b>50 MHz single element ultrasonic transducer, mechanic linear scanning method is used in the imaging system. The resolution and the ability of recognize the skin issue is verified by linear target scanning and clinical trials.</p><p><b>RESULTS</b>Both the axial and lateral resolution of the system reaches 50 microm. The subtle structure of normal skin tissue is clearly visible. Some diseases have obvious appearance in the image.</p><p><b>CONCLUSIONS</b>50 MHz ultrasonic skin imaging system is of high resolution and is valuable to skin structure detect and disease diagnosis.</p>