Safety of COVID-19 vaccine in patients with myasthenia gravis: a self-controlled case series study.

Background: The safety of COVID-19 vaccines has been clarified in clinical trials; however, some immunocompromised patients, such as myasthenia gravis (MG) patients, are still hesitant to receive vaccines. Whether COVID-19 vaccination increases the risk of disease worsening in these patients remains unknown. This study aims to evaluate the risk of disease exacerbation in COVID-19-vaccinated MG patients. Methods: The data in this study were collected from the MG database at Tangdu Hospital, the Fourth Military Medical University, and the Tertiary Referral Diagnostic Center at Huashan Hospital, Fudan University, from 1 April 2022 to 31 October 2022. A self-controlled case series method was applied, and the incidence rate ratios were calculated in the prespecified risk period using conditional Poisson regression. Results: Inactivated COVID-19 vaccines did not increase the risk of disease exacerbation in MG patients with stable disease status. A few patients experienced transient disease worsening, but the symptoms were mild. It is noted that more attention should be paid to thymoma-related MG, especially within 1 week after COVID-19 vaccination. Conclusion: COVID-19 vaccination has no long-term impact on MG relapse.

A correlation study affecting survival in patients after radical colon cancer surgery: A retrospective study.

The objective of this study was to explore the relevant factors affecting the 5-year survival rate of patients after radical colon cancer surgery, and to provide some basis for improving the quality of life and prognosis of colon cancer patients. The clinical data of 116 colon cancer patients who underwent treatment in our hospital from January 2017 to December 2017 were retrospectively selected. Using the date of performing surgical treatment as the starting point and the completion of 5 years after surgery or patient death as the end point, all patients were followed up by telephone to count the 5-year survival rate and analyze the influence of each factor with the prognosis of colon cancer patients. Of the 116 patients, 14 patients were lost to follow-up. Of the 102 patients with complete follow-up, 33 patients were died, with an overall 5-year survival rate of 67.6%. After univariate analysis, it was found that distant metastasis (χ2 = 10.493, P = .001), lymph node metastasis (χ2 = 25.145, P < .001), depth of muscle infiltration (χ2 = 14.929, P < .001), alcohol consumption (χ2 = 15.263, P < .001), and preoperative obstruction (χ2 = 9.555, P = .002) were significantly associated with the prognosis of colon cancer patients. Multivariate logistic analysis showed that distant metastasis (odds ratio [OR]: 1.932, 95% confidence intervals [CI]: 1.272-2.934, P = .002), lymph node metastasis (OR: 1.219, 95% CI: 1.091-1.362, P < .001), and obstruction (OR: 1.970, 95% CI: 1.300-2.990, P < .001) were significant independent risk factors affecting the prognosis in patients after radical colon cancer surgery. In summary, preoperative obstruction, lymph node metastasis, and distant metastasis are independent factors influencing 5-year survival rate after radical colon cancer surgery. Patients with risk factors should be followed up more closely and reasonable postoperative adjuvant chemotherapy regimens should be used to improve long-term survival.

Chinese expert consensus on the nursing management of the totally implantable venous access device.

The totally implantable venous access device (TIVAD) has been widely used in clinical nursing work in China. The use of TIVAD has significantly improved the safety of venous access and reduced the pain caused by a repeated puncture; however, it may also bring with it varying degrees of complications associated with the long-term insertion of TIVAD and the maintenance quality of the venous access. Standard maintenance of the venous access for TIVAD is very important for reducing complications and improving the efficacy and patient's quality of life. This consensus briefly describes the fundamental knowledge and operating procedures of TIVAD while focusing on the evaluation and management of perioperative nursing, the observation and treatment of complications, the operation methods, and precautions for maintenance of venous access, as well as health education. This agreement seeks to standardize the nursing care of TIVAD patients in China.

A high-integrated DNA biocomputing platform for MicroRNA sensing in living cells.

DNA logic computing has captured increasing interest due to its ability to assemble programmable DNA computing elements for disease diagnosis, gene regulation, and targeted therapy. In this work, we developed an aptamer-equipped high-integrated DNA biocomputing platform (HIDBP-A) with a dual-recognition function that enabled cancer cell targeting. Dual microRNAs were the input signals and can perform AND logic operations. Compared to the free DNA biocomputing platform (FDBP), the integration of all computing elements into the same DNA tetrahedron greatly improved logic computing speed and efficiency owing to the confinement effect reflected by the high local concentration of computing elements. As a proof of concept, the utilization of microRNA as the input signal was beneficial for improving the scalability and flexibility of the sequence design of the logic nano-platform. Given that the different microRNAs were over-expressed in cancer cells, this new HIDBP-A has great promise in accurate diagnosis and logic-controlled disease treatment.

Simultaneous Imaging of Dual microRNAs in Cancer Cells through Catalytic Hairpin Assembly on a DNA Tetrahedron.

Accurate detection and imaging of tumor-related microRNA (miRNA) in living cells hold great promise for early cancer diagnosis and prognosis. One of the challenges is to develop methods that enable the identification of multiple miRNAs simultaneously to further improve the detection accuracy. Herein, a simultaneous detection and imaging method of two miRNAs was established by using a programmable designed DNA tetrahedron nanostructure (DTN) probe that includes a nucleolin aptamer (AS1411), two miRNA capture strands, and two pairs of metastable catalytic hairpins at different vertexes. The DTN probe exhibited enhanced tumor cell recognition ability, excellent stability and biocompatibility, and fast miRNA recognition and reaction kinetics. It was found that the DTN probe could specifically enter tumor cells, in which the capture strand could hybridize with miRNAs and initiate the catalytic hairpin assembly (CHA) only when the overexpressed miR-21 and miR-155 existed simultaneously, resulting in a distinct fluorescence resonance energy transfer signal and demonstrating the feasibility of this method for tumor diagnosis.

Clinicopathologic features, treatment, survival, and prognostic factors of combined hepatocellular and cholangiocarcinoma: A nomogram development based on SEER database and validation in multicenter study.

PURPOSE: The aim of the study was to comprehensively understand the combined hepatocellular and cholangiocarcinoma (CHC) and develop a nomogram for prognostic prediction of CHC. METHODS: Data were collected from the Surveillance, Epidemiology and End Results (SEER) database (year 2004-2014). Propensity-score matching (PSM) was used to match the demographic characteristic of the CHC versus hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). A nomogram model was established to predict the prognosis in terms of cancer specific survival (CSS). The established nomogram was externally validated by a multicenter cohort. RESULTS: A total of 71,756 patients enrolled in our study including 62,877 HCC patients, 566 CHC patients, and 8303 ICC patients. The CHC, HCC, and ICC are not exactly similar in clinical characteristic. After PSM, the CSS of CHC was better than HCC but comparable to ICC. Tumor size, M stage, surgery, chemotherapy, and surgery were independently prognostic factors of CHC and were included in the establishment of novel nomogram. The c-index of the novel nomogram in SEER training set and multicenter validation was 0.779 and 0.780, respectively, which indicated that the model was with better discrimination power. In addition, decision curve analyses proved the favorable potential clinical effect of the predictive model. Lastly, a risk classification based on nomogram also verified the reliability of the model. CONCLUSION: CHC had better survival than HCC but was comparable to ICC. The nomogram was established based on tumor size, M stage, chemotherapy, surgery, and radiotherapy and well validated by external multicenter cohort.

Sensitive Logic Nanodevices with Strong Response for Weak Inputs.

Sensitive sensing is critical when developing new calculation systems with weak input signals (ISs). In this work, a "weak-inputs-strong-outputs" strategy was proposed to guide the construction of sensitive logic nanodevices by coupling an input-induced reversible DNA computing platform with a hybridization chain reaction-based signal amplifier. By rational design of the sequence of computing elements (CEs) so as to avoid cross-talking between ISs and signal amplifier, the newly formed logic nanodevices have good sensitivity to the weak ISs even at low concentrations of CEs, and are able to perform YES, OR, NAND, NOR, INHIBIT, INHIBIT-OR and number classifier operation, showing that the DNA calculation proceeds in dilute solution medium that greatly improves the calculation proficiency of logic nanodevices without the confinement of the lithography process in nanotechnology.

A centrifugal microfluidic chip for point-of-care testing of staphylococcal enterotoxin B in complex matrices.

Staphylococcal enterotoxin B (SEB) is a typical biological toxin that causes food poisoning. Currently reported SEB detection methods have the drawbacks of sophisticated sample preparation and being time-consuming and labor-intensive. Herein, we propose a strategy based on an immune sandwich structure operating on a centrifugal microfluidic chip for point-of-care testing (POCT) of SEB. The fluorescent microparticle-labeled primary antibody (CM-EUs-Ab1), capture antibody (CAb), and goat anti-mouse IgG antibody (SAb) were modified on the bond area, T-area, and C-area, respectively. When SEB was added, it first reacted with the CM-EUs-Ab1 through the specific recognition between SEB and the Ab1. Then, under capillarity, the conjugates of SEB and the CM-EUs-Ab1 were captured by the CAb when they flowed to the T-area, and the remaining CM-EUs-Ab1 bound with the SAb in the C-area. Finally, this chip was put into a dry fluorescence detection analyzer for centrifugation and on-site detection of SEB. The fluorescence intensity ratio of the T-area to the C-area was positively correlated with the concentration of SEB. The resulting linear range was 0.1-250 ng mL-1, and the limit of detection (3σ/k) was 68 pg mL-1. This POCT platform only needs 20 µL of sample and can realize the full process of detection within 12 min. This chip also exhibits good stability for 35 days. Additionally, the proposed method has been successfully utilized for the detection of SEB in urine, milk, and juice without any pre-treatment of the samples. Thus, this platform is expected to be applied to food safety testing and clinical diagnosis.

Evaluation of the efficiency of calcium and vitamin D in treating adults with corticosteroid-induced osteoporosis: A protocol for systematic review and meta-analysis.

BACKGROUND: Administering corticosteroid is an effective therapeutic strategy for treating most inflammatory conditions. However, there is a chance for corticosteroid treatment to adversely affect bones, resulting in corticosteroid-induced osteoporosis, which is a highly prevalent type of secondary osteoporosis. Elevated bone resorption and reduced formation of bone are pathogenesis indicators of corticosteroid-induced osteoporosis. Preventative therapy is recommended for patients initiating steroids. This study aims to evaluate the efficiency of calcium and vitamin D in treating adults diagnosed with osteoporosis caused by corticosteroid therapy. METHODS: Electronic databases will be searched systematically to source studies that have evaluated the efficiency of calcium and vitamin D as a treatment method for adult patients with osteoporosis from corticosteroid therapy. The databases include, PubMed, EMBASE, the Cochrane Library, Scopus, and Web of Science. The timeline of the search will be limited from inception to November 2020. This study will utilize the Cochrane risk of bias tool to assess the quality of the studies reviewed. Moreover, appropriate methods will be chosen to analyze the data. The RevMan 5.3 software is utilized to perform statistical analysis. RESULTS: This study will provide additional practical and targeted results of evaluating the efficiency of calcium and vitamin D in treating adults with corticosteroid-induced osteoporosis. CONCLUSION: The results of this study will provide further evidence about calcium and vitamin D in treating adults with corticosteroid-induced osteoporosis, clinicians and policymakers can make practical use of the results. ETHICS AND DISSEMINATION: Since this systematic review does not involve any human or animal participants, an ethics approval is not required. SYSTEMATIC REVIEW REGISTRATION: Aug 19, 2021. osf.io/zvb38. (https://osf.io/zvb38/).

A portable personal glucose meter method for enzyme activity detection and inhibitory activity evaluation based on alkaline phosphatase-mediated reaction.

In this study, an effective and portable method for enzyme activity detection and inhibitory activity evaluation was developed based on the alkaline phosphatase (ALP)-mediated reaction in a personal glucose meter (PGM). In this method, ALP catalyzes the hydrolysis of substrate amifostine (WR-2721) to produce ethanethiol (WR-1065), which can trigger the reduction of ferricyanide (K3[Fe(CN)6]), an electron transfer mediator in glucose test strips, to ferrocyanide ([K4Fe(CN)6]) and generate a PGM-detectable signal. Thus, WR-1065 can be directly quantified by a PGM as simply as detecting glucose in blood. After being systematically optimized, the method was applied to evaluate the inhibitory activity of ten small-molecule compounds and six Cordyceps sinensis (CS) extracts on ALP. The results showed that adenosine-5-monophosphate and theophylline had high inhibitory activity, but two CS extracts have promotion potency on ALP with the values of -20.7 ± 1.3% and -46.6 ± 2.1%, respectively. Moreover, the binding sites and modes of small-molecule compounds to ALP were investigated by molecular docking, while a new substrate competitor with theoretically good inhibitory activity against ALP was designed by scaffold hopping. Finally, the accuracy of the PGM method for enzyme activity detection was assessed by detecting ALP from milk samples, and the recovery ranged from 87.7% to 116.9%. These results indicate that it is feasible to evaluate enzyme activity and the inhibitory activity of small-molecule compounds and CS extracts on ALP using a PGM based on ALP-mediated reaction. Graphical abstract.

A crosslinked submicro-hydrogel formed by DNA circuit-driven protein aggregation amplified fluorescence anisotropy for biomolecules detection.

Protein is an excellent molecular mass amplifier without fluorescence quenching effect for fluorescence anisotropy (FA) assay. However, in traditional protein amplified FA methods, the binding ratio between amplifier and dye-modified probe is 1:1 or one target can only induce FA change of one fluorophore on probe, resulting in low sensitivity. Herein, we developed a simple FA strategy with high accuracy and sensitivity by using a crosslinked submicro-hydrogel that was formed through a catalyzed hairpin assembly (CHA) assisted protein aggregation as a novel FA amplifier. In the presence of catalyst, the CHA process was initiated through the toehold-mediated strand exchange reaction, which led to the formation of a dye and biotin-labeled Y-shaped H1-H2 duplex (YHD) and recycling of catalyst. With the introduction of streptavidin, a crosslinked submicro-hydrogel was formed by strong binding affinity between biotin on YHD and streptavidin, resulting in an increased FA of fluorescent dye. After rational design of the catalyst sequence, this method has been utilized for the detection of miRNA-145, staphylococcal enterotoxin B (SEB) and ATP with an LOD of 2.5 nM, 92 pg mL-1 and 3.6 µM, respectively. Moreover, this FA assay has been successfully applied for direct detection of target in biological samples, demonstrating its practicality in complex biological systems.

Chirality transfer of cysteine to the plasmonic resonance region through silver coating of gold nanobipyramids.

Here we report a chirality transfer of cysteine, which at first was to the plasmonic resonance region of gold nanobipyramids and then to that of Ag nanoshells with increasing growth of Ag layers, owing to the important role of the free Cys embedded within the Ag nanoshell. Our finding is helpful for developing new chiral plasmonic nanomaterials with the best designed asymmetric properties.

Hierarchical Hybridization Chain Reaction for Amplified Signal Output and Cascade DNA Logic Circuits.

In this work, we propose a three-layer hierarchical hybridization chain reaction (3L hHCR) composed of 1stHCR, 2ndHCR, and 3rdHCR to achieve robust signal amplification efficiency and broaden the applied range of HCR-based systems. In principle, the execution of superior HCR generates the formation of the initiator (named as 2ndI or 3rdI) of the subordinate HCR that relies on the introduction of the target sequence (1stI). To avoid the high background signal of the 3L hHCR system, a strategy of "splitting reconstruction" was adopted. The initiator of the subordinate HCR was designed as two separate fragments (splitting) that are obtained together (reconstruction) for the motivation of the subordinate HCR after the completion of the superior HCR. The implementation of the entire 3L hHCR system generates significant fluorescence recovery that derives from the impediment of Förster resonance energy transfer between fluorophore and quencher; thus, ultrasensitive detection of 1stI in the range of 50 pM to 10 nM can be achieved. Surprisingly, when the concentration of 1stI is lower than 1 nM, the 3L hHCR shows excellent ability to discriminate against various concentrations of 1stI, which is better than that of the 2L hHCR I system. Due to the hierarchical self-assembly mechanism, the 3L hHCR can also be reliably operated as a cascade AND logic gate with a high specificity and molecular keypad lock with a prompt error-reporting function. Furthermore, the 3L hHCR-based molecular keypad lock also shows potential application in the accurate diagnosis of cancer. The 3 L hHCR shows visionary prospects in biosensing and the fabrication of advanced biocomputing networks.

Nucleolin-Targeted DNA Nanotube for Precise Cancer Therapy through Förster Resonance Energy Transfer-Indicated Telomerase Responsiveness.

Precise drug delivery holds great promise in cancer treatment but still faces challenges in controllable drug release in tumor cells specifically. Herein, a nucleolin-targeted and telomerase-responsive DNA nanotube for drug release was developed. First, a DNA nanosheet with four capture strands on its surface was prepared, which could bind and load ricin A chain (RTA). The RTA-loaded nanosheet was further converted into a DNA nanotube with a high Förster resonance energy transfer (FRET) efficiency in the presence of a Cy3-modified DNA fastener by hybridizing with the Cy5-modified DNA and another DNA-containing telomerase primer sequence along the long sides. Moreover, the aptamer of nucleolin was assembled on the DNA nanotube by combining with the hybrid chain at the terminal. The aptamer-functionalized and RTA-loaded DNA nanotube displayed enhanced tumor permeability and precise drug release in response to the telomerase in tumor cells, following the change of the FRET signal and RTA-induced cell death. Moreover, the DNA nanotube was applied successfully in vivo, and there was an obvious inhibition of tumor growth on xenograft-bearing mice following systemic administration, indicating that the constructed DNA nanotube represents a promising platform for precise RTA delivery in target cancer therapy.

Autophagy is involved in the replication of H9N2 influenza virus via the regulation of oxidative stress in alveolar epithelial cells.

BACKGROUND: Oxidative stress is an important pathogenic factor in influenza A virus infection. It has been found that reactive oxygen species induced by the H9N2 influenza virus is associated with viral replication. However, the mechanisms involved remain to be elucidated. METHODS: In this study, the role of autophagy was investigated in H9N2 influenza virus-induced oxidative stress and viral replication in A549 cells. Autophagy induced by H9N2 was inhibited by an autophagy inhibitor or RNA interference, the autophagy level, viral replication and the presence of oxidative stress were detected by western blot, TCID50 assay, and Real-time PCR. Then autophagy and oxidative stress were regulated, and viral replication was determined. At last, the Akt/TSC2/mTOR signaling pathways was detected by western blot. RESULTS: Autophagy was induced by the H9N2 influenza virus and the inhibition of autophagy reduced the viral titer and the expression of nucleoprotein and matrix protein. The blockage of autophagy suppressed the H9N2 virus-induced increase in the presence of oxidative stress, as evidenced by decreased reactive oxygen species production and malonaldehyde generation, and increased superoxide dismutase 1 levels. The changes in the viral titer and NP mRNA level caused by the antioxidant, N-acetyl-cysteine (NAC), and the oxidizing agent, H2O2, confirmed the involvement of oxidative stress in the control of viral replication. NAC plus transfection with Atg5 siRNA significantly reduced the viral titer and oxidative stress compared with NAC treatment alone, which confirmed that autophagy was involved in the replication of H9N2 influenza virus by regulating oxidative stress. Our data also revealed that autophagy was induced by the H9N2 influenza virus through the Akt/TSC2/mTOR pathway. The activation of Akt or the inhibition of TSC2 suppressed the H9N2 virus-induced increase in the level of LC3-II, restored the decrease in the expression of phospho-pAkt, phospho-mTOR and phospho-pS6 caused by H9N2 infection, suppressed the H9N2-induced increase in the presence of oxidative stress, and resulted in a decrease in the viral titer. CONCLUSION: Autophagy is involved in H9N2 virus replication by regulating oxidative stress via the Akt/TSC2/mTOR signaling pathway. Thus, autophagy maybe a target which may be used to improve antiviral therapeutics.

Ultrathin Densified Carbon Nanotube Film with "Metal-like" Conductivity, Superior Mechanical Strength, and Ultrahigh Electromagnetic Interference Shielding Effectiveness.

Flexible and lightweight high-performance electromagnetic interference shielding materials with minimal thickness, excellent mechanical properties, and outstanding reliability are highly desired in the field of fifth-generation (5G) communication, yet remain extremely challenging to manufacture. Herein, we prepared an ultrathin densified carbon nanotube (CNT) film with superior mechanical properties and ultrahigh shielding effectiveness. Upon complete removal of impurities in pristine CNT film, charge separation in individual CNTs induced by polar molecules leads to strong CNT-CNT attraction and film densification, which significantly improve the electrical conductivity, shielding performance, and mechanical strength. The tensile strength is up to 822 ± 21 MPa, meanwhile the electrical conductivity is as high as 902,712 S/m, and the density is only 1.39 g cm-3. Notably, the shielding effectiveness is over 51 dB with a thickness of merely 1.85 µm in the broad frequency range of 4-18 GHz, and it reaches to ∼82 dB at 6.36 µm and ∼101 dB at 14.7 µm, respectively. Further, such CNT film exhibits excellent reliability after an extended period in strong acid/alkali, high temperature, and high humidity. It demonstrates the best overall performance among representative shielding materials by far, representing a critical breakthrough in the preparation of shielding film toward applications in wearable electronics and 5G communication.

Genomic characterization and phylogenetic evolution of the SARS-CoV-2.

 The coronavirus disease 2019 (COVID-19) starting on 12 December 2019 in Wuhan, China, caused 7,885,123 cases including 431,835 deaths by 14 Jun 2020 all over the world. Here we report the genomic characterization and phylogenetic evolution of coronavirus SARS-CoV-2 causing COVID-19. The SARS-CoV-2 and other coronavirus genomes were obtained from GISAID and GenBank. The genomes were annotated and potential genetic recombination was investigated. Phylogenetic analysis was conducted and used to determine the evolutionary history of the virus and to elucidate the origin of the virus. The analysis had revealed that SARS-CoV-2 possessed a similar genomic organization to bat-SARS-like-CoV collected in China. The genome sequences of SARS-CoV-2 were very similar, showing 99.6-100% sequence identity. Notably, SARS-CoV-2 was closely related (with 88% identity) to bat-SARS-like coronavirus, but was more distant from SARS-CoV (about 79%) and MERS-CoV (about 50%). Phylogenetic tree of the complete viral genome showed that the virus clustered with bat SARS-like coronavirus. The results of the similarity between SARS-CoV-2 and related viruses did not identify any potential genomic recombination events. Therefore, it seems that the SARS-CoV-2 might be originally hosted by bats, and might have been transmitted to humans via intermediate hosts of currently unknown wild animal(s). Finally, based on the wide spread of SARS-CoV in their natural reservoirs, future studies should focus more on surveillance of coronaviruses, and measures against the domestication and consumption of wild animals should be implemented. Keywords: coronavirus; SARS coronavirus; SARS-CoV-2; genomic characterization; phylogenetic evolution.

Online Liquid Microextraction Coupled with HPLC-ABTS for Rapid Screening of Natural Antioxidants: Case Study of Three Different Teas.

In the present study, an online liquid extraction coupled with high-performance liquid chromatography-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (HPLC-ABTS) system for rapid screening of antioxidants in tea samples was proposed. As an example, the tea samples were firstly extracted by online HPLC extractor with mobile phase at 70°C, then the hyphenated HPLC-ABTS was used for the chromatographic separation on a Poroshell EC C18 column by 0.3% aqueous formic acid and acetonitrile with a gradient elution at 1.5 mL·min-1, and the UV and antioxidant chromatograms with detection wavelengths at 270 nm and 750 nm were recorded, respectively. The established system integrated the processes of online HPLC sample extraction, HPLC separation and online antioxidants detection, the total analysis time of which was <20 min. The developed method was successfully applied to samples of green tea, oolong tea and black tea. As a result, 11 antioxidants were found in tea samples, including gallocatechin, epigallocatechin, catechin, chlorogenic acid, epicatechin, epigallocatechingallate, epicatechingallate, rutin, 1,4,6-trigalloylglucose, quercetin-3-glycoside and kaempferol-3-glucoside. The combined online liquid microextraction and online HPLC-ABTS method is a rapid and green approach for the quality evaluation of tea.

Molecular characterization and pathogenesis of H9N2 avian influenza virus isolated from a racing pigeon.

H9N2 avian influenza viruses (AIVs) can cross species barriers and expand from birds tomammals and humans. It usually leads to economic loss for breeding farms and poses a serious threat to human health.This study investigated the molecular characteristics of H9N2 AIV isolated from a racing pigeon and its pathogenesis in BALB/c mice and pigeons. Phylogenetic analysis indicated that the H9N2 virus belonged to the Ck/BJ/94-like lineage, and acquired multiple specific amino acid substitutions that might contribute to viral transmission from birds to mammals and humans. A pathogenesis study showed that both mice and pigeons infected with H9N2 virus showed clinical signs and mortality. The H9N2 viruses efficiently replicated in mice and pigeons. In our study, high levels of viral shedding were detected in pigeons, but the infection was not transmitted to co-housed pigeons. Histopathological examination revealed the presence of inflammatory responses in the infected mice and pigeons. Immunohistochemical analysis showed the presence of H9N2 virus in multiple organs of the infected mice and pigeons. Moreover, the infected mice and pigeons demonstrated significant cytokine/chemokine production. Our results showed that the H9N2 virus can infect mice and pigeons, and can not be transmitted between pigeons through direct contact.

DNA nanosheet as an excellent fluorescence anisotropy amplification platform for accurate and sensitive biosensing.

Recently, various inorganic nanomaterials have been used as fluorescence anisotropy (FA) enhancers for biosensing successfully. However, most of them are size-uncontrollable and possess an intensive fluorescence quenching ability, which will seriously reduce the accuracy and sensitivity of FA method. Herein, we report a two-dimensional DNA nanosheet (DNS) without fluorescence quenching effect as a novel FA amplification platform. In our strategy, fluorophore-labeled probe DNA (pDNA) is linked onto the DNS surface through the hybridization with the handle DNA (hDNA) that extended from the DNS, resulting in the significantly enhanced FA value. After the addition of target, the pDNA was released from the DNS surface due to the high affinity between the hDNA and target, and the FA was decreased. Thus, target could be detected by the significantly decreased FA value. The linear range was 10-50 nM and the limit of detection was 8 nM for the single-stranded DNA detection. This new method is general and has been also successfully applied for the detection of ATP and thrombin sensitively. Our method improved the accuracy of FA assay and has great potential to detect series of biological analytes in complex biosensing systems.