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1.
Aggregate (Hoboken, N.J.) ; 2022.
Article in English | EuropePMC | ID: covidwho-1824576

ABSTRACT

The ongoing outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) pandemic has posed significant challenges in early viral diagnosis. Hence, it is urgently desirable to develop a rapid, inexpensive, and sensitive method to aid point‐of‐care SARS‐CoV‐2 detection. In this work, we report a highly sequence‐specific biosensor based on nanocomposites with aggregation‐induced emission luminogens (AIEgen)‐labeled oligonucleotide probes on graphene oxide nanosheets (AIEgen@GO) for one step‐detection of SARS‐CoV‐2‐specific nucleic acid sequences (Orf1ab or N genes). A dual “turn‐on” mechanism based on AIEgen@GO was established for viral nucleic acids detection. Here, the first‐stage fluorescence recovery was due to dissociation of the AIEgen from GO surface in the presence of target viral nucleic acid, and the second‐stage enhancement of AIE‐based fluorescent signal was due to the formation of a nucleic acid duplex to restrict the intramolecular rotation of the AIEgen. Furthermore, the feasibility of our platform for diagnostic application was demonstrated by detecting SARS‐CoV‐2 virus plasmids containing both Orf1ab and N genes with rapid detection around 1 h and good sensitivity at pM level without amplification. Our platform shows great promise in assisting the initial rapid detection of the SARS‐CoV‐2 nucleic acid sequence before utilizing quantitative reverse transcription‐polymerase chain reaction for second confirmation. An AIEgen‐graphene oxide (GO) nanocomposite‐based assay is designed for rapid detection of SARS‐CoV‐2 nucleic acids. The sensing mechanism is based on two‐stage fluorescence signal recovery due to fluorescence resonance energy transfer (FRET) effect by detaching AIEgen from GO surface and restricted intramolecular rotation (RIR) effect by formation of nucleic acid duplexes.

2.
International Review of Financial Analysis ; : 102169, 2022.
Article in English | ScienceDirect | ID: covidwho-1799888

ABSTRACT

In this study, we construct China's aggregate sentiment indicator (SsPCA) based on the method of Huang et al. (2021a), which employs a new dimension reduction method of scaled principal component analysis (PCA), to aggregate useful information from individual sentiment proxies, and further examine its return predictability for the Chinese stock market. The empirical evidence suggests that SsPCA significantly improves the prediction accuracy for stock market returns both in and out of the sample, and also obtains considerable economic gain for a mean-variance investor. Additionally, the forecasting effect of SsPCA is superior to that of SPCA and SPLS, evaluated using the traditional PCA and partial least square methods, respectively. Moreover, relative to the period of the bull market, SsPCA exhibits better ability in forecasting stock market returns during the bear market. Finally, special events, such as the outbreak of coronavirus disease 2019 (COVID-19), also affect the predictive performance of the sentiment indicator.

3.
Adv Sci (Weinh) ; 9(17): e2105904, 2022 06.
Article in English | MEDLINE | ID: covidwho-1782563

ABSTRACT

Infectious virus outbreaks pose a significant challenge to public healthcare systems. Early and accurate virus diagnosis is critical to prevent the spread of the virus, especially when no specific vaccine or effective medicine is available. In clinics, the most commonly used viral detection methods are molecular techniques that involve the measurement of nucleic acids or proteins biomarkers. However, most clinic-based methods require complex infrastructure and expensive equipment, which are not suitable for low-resource settings. Over the past years, smartphone-based point-of-care testing (POCT) has rapidly emerged as a potential alternative to laboratory-based clinical diagnosis. This review summarizes the latest development of virus detection. First, laboratory-based and POCT-based viral diagnostic techniques are compared, both of which rely on immunosensing and nucleic acid detection. Then, various smartphone-based POCT diagnostic techniques, including optical biosensors, electrochemical biosensors, and other types of biosensors are discussed. Moreover, this review covers the development of smartphone-based POCT diagnostics for various viruses including COVID-19, Ebola, influenza, Zika, HIV, et al. Finally, the prospects and challenges of smartphone-based POCT diagnostics are discussed. It is believed that this review will aid researchers better understand the current challenges and prospects for achieving the ultimate goal of containing disease-causing viruses worldwide.


Subject(s)
COVID-19 , Zika Virus Infection , Zika Virus , COVID-19/diagnosis , Clinical Laboratory Techniques , Humans , Laboratories , Point-of-Care Testing , Smartphone , Zika Virus Infection/diagnosis
4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315995

ABSTRACT

We explore the role of economic uncertainty shocks in oil prices by establishing a new time-varying parameter oil market model based on Kilian (2009). The main conclusions are as follows. First, according to the two-stage nonlinear testing that we propose in this paper, the variables in the oil market model are significantly nonlinearly correlated;therefore, we extend the constant coefficient oil market model using time-varying parameterisation. Second, the time-varying impulse responses indicate that the effects of economic uncertainty shocks on crude oil price returns are time-varying and tend to run counter to the oil market cycle. Third, the time-varying forecast error variance decomposition infers that economic uncertainty shocks can contribute more than fundamental shocks to variations in oil price returns under certain market conditions, such as during the global financial crisis period in 2008. Fourth, during the recent coronavirus crisis of 2020, economic uncertainty shocks and oil demand shocks are two important contributors to the variations in oil price returns, with economic uncertainty shocks contributing to about 40% and demand shocks contributing to about 50% of the variations.

5.
ACS Appl Mater Interfaces ; 14(3): 4714-4724, 2022 Jan 26.
Article in English | MEDLINE | ID: covidwho-1655444

ABSTRACT

Surface-enhanced Raman scattering (SERS)-based biosensors are promising tools for virus nucleic acid detection. However, it remains challenging for SERS-based biosensors using a sandwiching strategy to detect long-chain nucleic acids such as nucleocapsid (N) gene of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because the extension of the coupling distance (CD) between the two tethered metallic nanostructures weakens electric field and SERS signals. Herein, we report a magnetic-responsive substrate consisting of heteoronanostructures that controls the CD for ultrasensitive and highly selective detection of the N gene of SARS-CoV-2. Significantly, our findings show that this platform reversibly shortens the CD and enhances SERS signals with a 10-fold increase in the detection limit from 1 fM to 100 aM, compared to those without magnetic modulation. The optical simulation that emulates the CD shortening process confirms the CD-dependent electric field strength and further supports the experimental results. Our study provides new insights into designing a stimuli-responsive SERS-based platform with tunable hot spots for long-chain nucleic acid detection.


Subject(s)
Biosensing Techniques/methods , COVID-19/diagnosis , Nucleic Acids/isolation & purification , SARS-CoV-2/isolation & purification , COVID-19/genetics , COVID-19/virology , Gold/chemistry , Humans , Limit of Detection , Metal Nanoparticles/chemistry , Nucleic Acids/chemistry , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Silver/chemistry , Spectrum Analysis, Raman/methods
6.
ACS Appl Mater Interfaces ; 12(50): 55614-55623, 2020 Dec 16.
Article in English | MEDLINE | ID: covidwho-1387129

ABSTRACT

Multiplexed detection of viral nucleic acids is important for rapid screening of viral infection. In this study, we present a molybdenum disulfide (MoS2) nanosheet-modified dendrimer droplet microarray (DMA) for rapid and sensitive detection of retroviral nucleic acids of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) simultaneously. The DMA platform was fabricated by omniphobic-omniphilic patterning on a surface-grafted dendrimer substrate. Functionalized MoS2 nanosheets modified with fluorescent dye-labeled oligomer probes were prepatterned on positively charged amino-modified omniphilic spots to form a fluorescence resonance energy transfer (FRET) sensing microarray. With the formation of separated microdroplets of sample on the hydrophobic-hydrophilic micropattern, prepatterned oligomer probes specifically hybridized with the target HIV genes and detached from the MoS2 nanosheet surface due to weakening of the adsorption force, leading to fluorescence signal recovery. As a proof of concept, we used this microarray with a small sample size (<150 nL) for simultaneous detection of HIV-1 and HIV-2 nucleic acids with a limit of detection (LOD) of 50 pM. The multiplex detection capability was further demonstrated for simultaneous detection of five viral genes (HIV-1, HIV-2, ORFlab, and N genes of SARS-COV-2 and M gene of Influenza A). This work demonstrated the potential of this novel MoS2-DMA FRET sensing platform for high-throughput multiplexed viral nucleic acid screening.


Subject(s)
Biosensing Techniques , COVID-19/diagnosis , HIV Infections/diagnosis , HIV/isolation & purification , COVID-19/genetics , COVID-19/virology , Disulfides/chemistry , Fluorescence , Fluorescence Resonance Energy Transfer , HIV/pathogenicity , HIV Infections/genetics , HIV Infections/virology , Humans , Molybdenum/chemistry , Nanostructures/chemistry , Nucleic Acids/genetics , Nucleic Acids/isolation & purification , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity
7.
Blood ; 136(Supplement 1):22-23, 2020.
Article in English | PMC | ID: covidwho-1339020

ABSTRACT

Background: A previously unknown beta-coronavirus was discovered through the use of unbiased sequencing in samples from patients with pneumonia. The virus was named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the international committee for the classification of viruses (ICTV). The disease caused by this virus was named as coronavirus disease 2019 (COVID-19). In addition to pulmonary manifestations, hematological changes such as lymphocytopenia, thrombocytopenia, and coagulation dysfunction can also be found in COVID-19 patients, and the mechanism is still unclear.Case data and methods: A total of 633 COVID-19 patients from Wuhan hospital of China were retrospectively analyzed. Clinical case data of all patients were collected, including gender, age, chronic underlying diseases, outcome, and blood laboratory test results. The hematological features of COVID-19 patients and the factors affecting their outcome were analyzed.Results: Of 633 patients with COVID-19, the median age was 62 years (interquartile range, IQR, 51.0-70.0) and 330 (52%) were men. Lymphocytopenia (lymphocyte count, 1.0 ×109 / L [IQR, 0.7-1.4]) occurred in 317/607 patients (52%), thrombocytopenia (platelet count <100 × 109/ L) occurred in 14/62 death patients (23%), prolonged prothrombin time (13.8 seconds [IQR, 13.1-15.1]) in 289/486 patients (59%), increased D-Dimer level (0.7 mg/L[IQR, 0.2-2.9]) in 230/411 patients (57%) and increased C-reactive protein levels (10.7 mg/L [IQR, 2.2-49.7]) in 217/426 patients (51%) . Compared with the survival patients, death patients have higher white blood cell count (11.7 × 109/L [IQR, 8.4 to 15.6]), neutrophil count (10.8 × 109/L [IQR, 7.8 to 13.9]), neutrophil count/lymphocyte count (20.5 [IQR, 12.4-34.2]), activated partial thromboplastin time (36.8 seconds [IQR, 31.3-42.3]), prothrombin time (17.1 seconds [IQR, 14.7 to 19.7]), D-Dimer level (4.6 mg/L [IQR, 1.0 to 7.8]), C-reactive protein level (111.8 mg/L (IQR, 53.1 to 196.6), and low lymphocyte count (0.5 × 109/L [IQR, 0.3 to 0.7]). The results of logistic multivariate regression analysis showed that age, neutrophil count, prothrombin time, and C-reactive protein were risk factors for patients with COVID-19.Conclusion: Hematological changes are common in patients with COVID-19. The early stage of the disease is mainly characterized by lymphocytopenia, thrombocytopenia, and the late stage may be characterized by more severe lymphocytopenia, even neutrophils elevation, elevated C-reactive protein, and severe coagulation disorder. The pathogenesis may be mediated by a direct viral infection and/or indirect immunopathology.

8.
Journal of Composites Science ; 5(7):190, 2021.
Article in English | MDPI | ID: covidwho-1314677

ABSTRACT

The deadly Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) outbreak has become one of the most challenging pandemics in the last century. Clinical diagnosis reports a high infection rate within a large population and a rapid mutation rate upon every individual infection. The polymerase chain reaction has been a powerful and gold standard molecular diagnostic technique over the past few decades and hence a promising tool to detect the SARS-CoV-2 nucleic acid sequences. However, it can be costly and involved in complicated processes with a high demand for on-site tests. This pandemic emphasizes the critical need for designing cost-effective and fast diagnosis strategies to prevent a potential viral source by ultrasensitive and selective biosensors. Two-dimensional (2D) transition metal dichalcogenide (TMD) nanocomposites have been developed with unique physical and chemical properties crucial for building up nucleic acid and protein biosensors. In this review, we cover various types of 2D TMD biosensors available for virus detection via the mechanisms of photoluminescence/optical, field-effect transistor, surface plasmon resonance, and electrochemical signals. We summarize the current state-of-the-art applications of 2D TMD nanocomposite systems for sensing proteins/nucleic acid from different types of lethal viruses. Finally, we identify and discuss the advantages and limitations of TMD-based nanocomposites biosensors for viral recognition.

9.
Front Cardiovasc Med ; 8: 680604, 2021.
Article in English | MEDLINE | ID: covidwho-1282380

ABSTRACT

Elderly with comorbidities have shown a higher rate of fatal outcomes when suffering coronavirus disease 2019 (COVID-19). However, a delineation of clinical significances of hematologic indices and underlying comorbidities in the progression and outcome of COVID-19 remains undefined. Six hundred two COVID-19 patients with established clinical outcomes (discharged or deceased) from Hankou Hospital of Wuhan, China between January 14, 2020 and February 29, 2020 were retrospectively analyzed. Of the 602 patients with COVID-19, 539 were discharged and 63 died in the hospital. The deceased group showed higher leukocyte and neutrophil counts but lower lymphocyte and platelet counts. Longer activated partial thromboplastin time (APTT) and prothrombin time (PT), as well as higher D-dimer and C-reactive protein levels, were found in non-survivors. Our observations suggest that these parameters could serve as potential predictors for the fatal outcome and in the discharged group. A higher neutrophil count and D-dimer level but lower lymphocyte were associated with a longer duration of hospitalization. A multivariable Cox regression analysis showed that higher neutrophil count, prolonged PT, and low lymphocyte count were risk factors for patients with COVID-19. Also, we found an association of lower lymphocyte count and higher C-reactive protein levels with the elderly group and those with cardiovascular-related comorbidities. The significantly different hematologic profiles between survivors and non-survivors support that distinct hematologic signatures in COVID-19 patients will dictate different outcomes as a prognostic marker for recovery or fatality. Lymphopenia and aggressive inflammatory response might be major causes for fatal outcomes in the elderly male and especially those with cardiovascular-related comorbidities.

10.
Cell Rep Phys Sci ; 2(1): 100288, 2021 Jan 20.
Article in English | MEDLINE | ID: covidwho-1009942

ABSTRACT

The novel coronavirus pandemic is sweeping the world and causing global crises. The lack of effective methods of early diagnosis and accurate detection may result in severe infection as well as mortality. Therefore, it is urgently required that rapid, selective, and accurate techniques for detecting pathogenic viruses are developed. Nanotechnology-based biosensors are finding many applications in biological detection, which may address these issues and realize direct detection of molecular targets in real time. Among various nanoplatforms, optical nanobiosensors have aroused much interest due to their inherent advantages of high sensitivity and direct readout. In this review, a summary of recent progress on the optical biosensors based on nanotechnology for pathogenic virus detection is provided, with focus on quantum dots (QDs), upconversion nanoparticles (UCNPs), noble metal nanoparticles, and organic fluorescent molecules-based nanoprobes and chemiluminescence assays. These representative studies demonstrate appealing performance as biosensors and hold great promise for clinical diagnosis.

11.
Mol Med Rep ; 22(6): 4485-4491, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-979150

ABSTRACT

In December 2019, an emergence of pneumonia was detected in patients infected with a novel coronavirus (CoV) in Wuhan (Hubei, China). The International Committee on Taxonomy of Viruses named the virus severe acute respiratory syndrome­CoV­2 and the disease CoV disease­19 (COVID­19). Patients with COVID­19 present with symptoms associated with respiratory system dysfunction and hematological changes, including lymphopenia, thrombocytopenia and coagulation disorders. However, to the best of our knowledge, the pathogenesis of COVID­19 remains unclear. Therefore, understanding the mechanisms underlying the hematological changes that manifest during COVID­19 may aid in the development of treatments and may improve patient prognosis.


Subject(s)
Betacoronavirus , Coronavirus Infections/blood , Pneumonia, Viral/blood , Antibodies, Viral/immunology , Antigen-Antibody Complex/immunology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Betacoronavirus/immunology , COVID-19 , Cellular Microenvironment , Coronavirus Infections/complications , Coronavirus Infections/drug therapy , Coronavirus Infections/therapy , Cytokine Release Syndrome/blood , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/prevention & control , Cytokines/blood , Diagnostic Tests, Routine , Endothelium, Vascular/pathology , Hematologic Tests , Hematopoiesis/drug effects , Hematopoietic Stem Cells/pathology , Humans , Hypoalbuminemia/etiology , Liver/physiopathology , Lung/physiopathology , Lymphopenia/etiology , Lymphopenia/physiopathology , Pandemics , Pneumonia, Viral/complications , Pneumonia, Viral/drug therapy , Pneumonia, Viral/therapy , Reperfusion Injury/etiology , SARS-CoV-2 , Thrombocytopenia/etiology , Thrombocytopenia/physiopathology , Thrombophilia/etiology
12.
Thromb Res ; 193: 110-115, 2020 09.
Article in English | MEDLINE | ID: covidwho-548091

ABSTRACT

Corona Virus Disease 2019 (COVID-19) is caused by the novel coronavirus SARS-CoV-2. Emerging genetic and clinical evidence suggests similarities between COVID-19 patients and those with severe acute respiratory syndrome and Middle East respiratory syndrome. Hematological changes such as lymphopenia and thrombocytopenia are not rare in COVID-19 patients, and a smaller population of these patients had leukopenia. Thrombocytopenia was detected in 5-41.7% of the patients with COVID-19. Analyzing the dynamic decrease in platelet counts may be useful in the prognosis of patients with COVID-19. However, the mechanisms underlying the development of thrombocytopenia remain to be elucidated. This review summarizes the hematological changes in patients infected with SARS-CoV-2 and possible underlying mechanisms of thrombocytopenia development.


Subject(s)
Blood Platelets/pathology , Coronavirus Infections/complications , Pneumonia, Viral/complications , Thrombocytopenia/etiology , Animals , Betacoronavirus/isolation & purification , Blood Coagulation , Blood Platelets/virology , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Humans , Pandemics , Platelet Count , Pneumonia, Viral/blood , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Prognosis , SARS-CoV-2 , Thrombocytopenia/blood , Thrombocytopenia/diagnosis , Thrombocytopenia/virology
13.
Ann Transl Med ; 8(4): 145, 2020 Feb.
Article in English | MEDLINE | ID: covidwho-8656
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