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As a practical rounded trailing edge airfoil for coaxial rotors, DBLN-526 is a fore and aft symmetrical airfoil with two steps on its lower side. This airfoil has been used at the inboard section of the coaxial rotor system. As there are always two eddies behind the airfoil because of its rounded trailing edge, the interaction between the separation and transition should be considered. Thus, the unsteady Reynolds-averaged Navier-Stokes- (RANS-) based γ − Re ¯ θ t model was used to analyze the unsteady transition and separation features. Three different rounded trailing-edge airfoils were compared with DBLN-526. Power spectrum density analysis and Δ Cl calculations demonstrated that the lift coefficient fluctuation of DBLN-526 was smaller than that of other rounded airfoils with different angles. Further investigation indicated that the locations of transition for DBLN-526 can be fixed at a wide range of angles by the unique design on its lower side. Because of this settled transition location, the size of separation is decreased, and the position of separation is settled as well, which leads to a lower lift coefficient fluctuation. The turbulent kinetic energy after the transition was higher, which injected a lot of energy into the boundary layer, and the separation zone near the transition position was relatively smaller. This study provides an indication for controlling separation and reducing unsteady fluctuations for rounded trailing edge airfoils. [ABSTRACT FROM AUTHOR]

A novel thermodynamic approach for integrating isothermal amplification with CRISPR detection in a closed assay vessel without the use of interior driving forces or human intervention was developed by harnessing internal air thermal expansion for autonomous liquid actuation by coupling a thermally responsive microfluidic cartridge with a simple two-step temperature profile. [Display omitted] • Seamless integration of CRISPR detection and target preamplification. • Automated actuation without external driving mechanism or human intervention. • Temperature-responsive architecture utilizes the internal air thermal expansion. • It shortens the sample-to-answer time without compromising sensitivity. The rising incidence of syphilis highlights the urgent need to develop molecular tests of Treponema pallidum at the point-of-care (POC). Traditional molecular approaches based on polymerase chain reaction (PCR) often involve expensive equipment, expert technicians, and lengthy turnaround time. Recently emerged approaches coupling CRISPR detection with isothermal amplification techniques hold great promise to advance the POC diagnostics, but commonly require multiple manual operations for postamplification reaction transfer or suffer from compromised performance in terms of sensitivity or assay time. To address these issues, we develop a thermometer-inspired microfluidic biosensing platform that seamlessly integrates CRISPR detection and isothermal amplification through temperature-programmed air expansion for intended fluidic manipulation. This platform not only allows for automated running of the canonical two-step recombinase polymerase amplification-CRISPR/Cas12a assay via a simple two-step temperature profile, but also provides a smartphone-enabled fluorescence readout with a limit of detection of a few DNA copies in 30 min. We detail the rational design of a thermally-responsive microfluidic cartridge and showcase how it harnesses the temperature difference in preamplification and CRISPR detection to implement the assay workflow without the need for an external driving mechanism or human intervention. Furthermore, we validate its applicability for rapid and sensitive detection of Treponema pallidum DNA in clinical samples (n = 30), exhibiting 100 % sensitivity and 100 % specificity compared to the quantitative PCR technique. The simplicity and effectiveness may lead this platform to be a powerful upgrade kit compatible with the existing CRISPR approaches, thus facilitating their widespread point-of-care diagnostic applications. [ABSTRACT FROM AUTHOR]

We introduce a novel and versatile microfluidic technology that allows parallel and multi-step bioanalytical procedures to be simply implemented by switching reagent-containing droplet arrays among alternative interaction zones for intended mass or energy transport in a programmable manner. This enables multiplexed complex bioassays for point-of-care testing. [ABSTRACT FROM AUTHOR]

Timely and accurate molecular diagnostics at the point-of-care (POC) level is critical to global health. To this end, we propose a handheld convective-flow real-time polymerase chain reaction (PCR) system capable of direct sample-to-answer genetic analysis for the first time. Such a system mainly consists of a magnetic bead-assisted photothermolysis sample preparation, a closed-loop convective PCR reactor, and a wireless video camera-based real-time fluorescence detection. The sample preparation exploits the dual functionality of vancomycin-modified magnetic beads (VMBs) for bacteria enrichment and photothermal conversion, enabling cell pre-concentration and lysis to be finished in less than 3 min. On the presented system, convective thermocycling is driven by a single-heater thermal gradient, and its amplification is monitored in real-time, with an analysis speed of less than 25 min, a dynamic linear range from 10 6 to 10 1 copies/µL and a detection sensitivity of as little as 1 copies/µL. Additionally, the proposed PCR system is self-contained with a control electronics, pocket-size and battery-powered, providing a low-cost genetic analysis in a portable format. Therefore, we believe that this integrated system may become a potential candidate for fast, accurate and affordable POC molecular diagnostics. [ABSTRACT FROM AUTHOR]

A handheld flow genetic analysis system (FGAS) is proposed for rapid, sensitive, multiplex and real-time quantification of nucleic acids at the point-of-care (POC) level. The FGAS includes a helical thermal-gradient microreactor and a microflow actuator, as well as control circuitry for temperature, fluid and power management, and smartphone fluorescence imaging. All of these features are integrated into a field-portable and easy-to-use molecular diagnostic platform powered by lithium batteries. Due to the unique design of the microreactor, not only steady temperatures for denaturation and annealing/extension but also a linear thermal gradient for spatial high-resolution melting can be achieved through simply maintaining a single heater at constant temperature. The smartphone fluorescence imaging system has a wide field of view that captures all PCR channels of the microreactor in a single snapshot without the need for any mechanical scanning. By these designs, the FGAS enables real-time monitoring of the temporal and spatial fluorescence signatures of amplicons during continuous-flow amplification. On the current FGAS, visual detection of as little as 10 copies per μL of genomic DNA of Salmonella enterica was achieved in 15 min, with real-time quantitative detection of the DNA over 6 orders of magnitude concentration from 106 to 101 copies per μL also completed in 7.5–15 min. In addition, multiple pathogenic DNA targets could be simultaneously discriminated with direct bar-chart readout or multiplex spatial melting in serial flow. We anticipate that the FGAS has great potential to become a next-generation gene analyzer for POC molecular diagnostics. [ABSTRACT FROM AUTHOR]

Highlights: [•] A high-throughput and rapid microfluidic method for pathogen detection is proposed. [•] The method offers a simple and convenient way toward high-throughput DNA analysis. [•] Important parameters of segmented continuous-flow multiplex PCR were investigated. [•] The proposed method is suitable for high-throughput biomedical monitoring. [Copyright &y& Elsevier]

Outdoor aerosol processes are often associated with disasters and diseases, which threaten human life and health. Outdoor aerosols are a fluid system affected by meteorological conditions and three-dimensional complex terrain. Their variable wind speed and direction and complex terrain boundary conditions make simulating advection processes difficult. Based on incompressible flow conditions, we designed an adaptive time step algorithm for forward advection for the rapid simulation of aerosol processes. The method is based on the first-order forward semi-Lagrangian advection method with unconditional mass conservation. The first-order truncated error coefficient function theory generates an adaptive time step to control the accuracy of forward advection. Smoke aerosol simulation experiments in two small outdoor scenes were designed, and the effects of the traditional backward advection and forward fixed step methods were compared with the algorithm in this study. The proposed simulation method showed improved accuracy compared with the other two methods in experimental scenarios; moreover, compared with those of the traditional backward method, the computation time was significantly reduced and the conservation of mass was significantly improved. Thus, the proposed method is a fast simulation method for outdoor aerosol numerical prediction. The first-order forward semi-Lagrangian method, which requires no iteration and less computation and offers unconditional conservation, was used. The law of truncation error coefficient of the first-order forward method was studied and an adaptive step algorithm was designed. Full-size real aerosol experiments in small-scale complex outdoor scenes were conducted for verification and comparison of simulation effects. [ABSTRACT FROM AUTHOR]

Rapid screening of infectious pathogens at the point-of-care (POC) is ideally low-cost, portable, easy to use, and capable of multiplex detection with high sensitivity. However, satisfying all these features in a single device without compromise remains a challenging task. Here, we introduce an ultraportable, automated RNA amplification testing device that allows rapid screening of infectious pathogens from clinical samples. In this device, 3D-printed structural parts incorporated with off-the-shelf mechanic/electronic components are utilized to create an inexpensive and automated droplet manipulation platform. On this platform, a simple configuration that couples a linear displacement of the chip with a tunable magnet array allows parallel and versatile droplet operations, including mixing, splitting, transporting, and merging. By exploiting a multi-channel droplet array chip to preload necessary reagents in "water-in-oil" format, bacteria lysis, RNA extraction and amplification are seamlessly integrated and implemented by the combination of droplet operations. Furthermore, visual readout and geometrically-multiplexed quantitative detection are provided by an integrated wireless video camera-enabled wide-field fluorescence imaging. We demonstrated that this droplet-based device could have a shorter RNA extraction time (12 min) and lower detection limits for pathogenic RNA (approaching to 102 copies per reaction). We also verified its clinical applicability for the rapid screening of four sexually transmitted pathogens from urine specimens. Results show that the sample-to-answer assay could be completed in approximately 42 min, with 100% concordance with the laboratory-based molecular testing. The exhibiting features may render this microdevice an easily accessible POC molecular diagnostic platform for infectious disease, especially in resource-limited settings. A pocket-sized microfluidic system automates multiplexed point-of-care RNA amplification testing for rapid screening of infectious pathogens from urine samples. [Display omitted] • An inexpensive microdevice automates multiplexed point-of-care molecular diagnosis. • It is made of 3D-printed parts with off-the-shelf mechanic/electronic components. • Multiplexed real-time detection by an ultracompact camera-enabled wide-field imaging. • Highly sensitive screening of 4 pathogens directly from urine samples in 42 min. • It is promising for screening of infectious diseases in resource-limited settings. [ABSTRACT FROM AUTHOR]

It is a major challenge for the airframe-inlet design of modern combat aircrafts, as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex. In this study, an aerodynamic/stealth optimization design method for an S-duct inlet is proposed. The upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow separation. The multilevel fast multipole algorithm (MLFMA) is utilized for the stealth adjoint equation. A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth characteristics. Both the aerodynamic and stealth characteristics of the inlet are effectively improved. Finally, the optimization results are analyzed, and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and cross-sectional area. The S-duct is smoothed, and the cross-sectional area is increased to improve the aerodynamic characteristics, while it is completely opposite for the stealth design. The radar cross section (RCS) is reduced by phase cancelation for low frequency conditions. The method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system. [ABSTRACT FROM AUTHOR]

Nanopore sequencers can enrich or deplete the targeted DNA molecules in a library by reversing the voltage across individual nanopores. However, it requires substantial computational resources to achieve rapid operations in parallel at read-time sequencing. We present a deep learning framework, NanoDeep, to overcome these limitations by incorporating convolutional neural network and squeeze and excitation. We first showed that the raw squiggle derived from native DNA sequences determines the origin of microbial and human genomes. Then, we demonstrated that NanoDeep successfully classified bacterial reads from the pooled library with human sequence and showed enrichment for bacterial sequence compared with routine nanopore sequencing setting. Further, we showed that NanoDeep improves the sequencing efficiency and preserves the fidelity of bacterial genomes in the mock sample. In addition, NanoDeep performs well in the enrichment of metagenome sequences of gut samples, showing its potential applications in the enrichment of unknown microbiota. Our toolkit is available at https://github.com/lysovosyl/NanoDeep. [ABSTRACT FROM AUTHOR]

This paper describes the first demonstration of the combination of micropatterned paper devices (μPPDs) and polydiacetylene (PDA) colorimetric probes for double-stranded DNA (dsDNA) detection with high sensitivity and fast response. The device is rapidly fabricated on paper by wax-screen-printing. The amine-functionalized PDA vesicles are spotted to the paper chambers, followed by the introduction of the polymerase chain reaction (PCR)-amplified dsDNA targets. After the completion of the ionic interactions between the targets and the probes, a significantly different optical signal is produced, thereby facilitating the naked-eye detection. Additionally, the signals are readily documented through a smartphone for quantitative analysis. In this study, the PDA colorimetric assay in μPPDs is capable of discriminating the presence of the target down to 10 nM (the typical concentration of PCR amplicons is around 100 nM). At such concentration, the value of colorimetric response in paper is about 41% higher than that in tube, leading to an enhanced sensitivity. In addition, the colorimetric reaction in μPPDs is accomplished in 1 min, and the analytical speed is much faster than that observed in tube. These results show that the paper-based PDA colorimetry should have greatly enhanced applications as a technology for DNA diagnostics. [ABSTRACT FROM AUTHOR]

Highlights: Extracellular vesicle (EV) multiplexing involves chemical, physical spatial, biological, or nanoparticle-based strategies. Multiplexing in EV biomarker development includes high-throughput screening as well as point-of-care testing platforms which to date have been applied mainly to EV surface proteins or internal cargo miRNAs. Multiplexed measurements at single-EV resolution are likely to revolutionize the applicability of EV analytes as biomarkers in complex and heterogeneous diseases. Extracellular vesicles (EVs) are cell-derived membranous particles that play a crucial role in molecular trafficking, intercellular transport and the egress of unwanted proteins. They have been implicated in many diseases including cancer and neurodegeneration. EVs are detected in all bodily fluids, and their protein and nucleic acid content offers a means of assessing the status of the cells from which they originated. As such, they provide opportunities in biomarker discovery for diagnosis, prognosis or the stratification of diseases as well as an objective monitoring of therapies. The simultaneous assaying of multiple EV-derived markers will be required for an impactful practical application, and multiplexing platforms have evolved with the potential to achieve this. Herein, we provide a comprehensive overview of the currently available multiplexing platforms for EV analysis, with a primary focus on miniaturized and integrated devices that offer potential step changes in analytical power, throughput and consistency. [ABSTRACT FROM AUTHOR]

Rapid and accurate identification of respiratory tract infection pathogens is of utmost importance for clinical diagnosis and treatment, as well as prevention of pathogen transmission. To meet this demand, a microfluidic chip-based PCR-array system, Onestart, was developed. The Onestart system uses a microfluidic chip packaged with all the reagents required, and the waste liquid is also collected and stored on the chip. This ready-to-use system can complete the detection of 21 pathogens in a fully integrated manner, with sample lysis, nucleic acid extraction/purification, and real-time PCR sequentially implemented on the same chip. The entire analysis process is completed within 1.5 h, and the system automatically generates a test report. The lower limit-of-detection (LOD) of the Onestart assay was determined to be 1.0 × 103 copies·mL−1. The inter-batch variation of cycle threshold (Ct) values ranged from 0.08% to 0.69%, and the intra-batch variation ranged from 0.9% to 2.66%. Analytical results of the reference sample mix showed a 100% specificity of the Onestart assay. The analysis of batched clinical samples showed consistency of the Onestart assay with real-time PCR. With its ability to provide rapid, sensitive, and specific detection of respiratory tract infection pathogens, application of the Onestart system will facilitate timely clinical management of respiratory tract infections and effective prevention of pathogen transmission. [ABSTRACT FROM AUTHOR]

Sensitive and accurate cell-free plasma Epstein-Barr virus (EBV) DNA measurement is essential in the routine diagnosis, monitoring and treatment of Nasopharyngeal Carcinoma (NPC). This measurement in commercial and in-house assay are commonly based on real-time quantitative PCR (qPCR) method, which requires reference materials for standardization and lack quantitative precision due to amplification bias or cross-contamination. To address these issues, we developed a CRISPR/Cas12a-mediated amplification-free digital DNA assay, which targets the repetitive sequences of EBV DNA and utilizes the cis -cleavage activity of CRISPR-Cas12a prior to droplet generation. By this mean, more activated Cas12a-crRNA duplexes could be produced for subsequent target detection and counting, thus improving the performance in detecting low EBV DNA load. We demonstrated that it was more robust than conventional qPCR for detecting plasma EBV DNA in a case-control study of 208 participants, especially when the target concentrations were around the diagnostic cut-off value for NPC. More importantly, this assay allowed a more accurate diagnosis of early-stage NPC, with an area under the curve (AUC) of 0.9883 (versus 0.7682 for qPCR). Furthermore, its absolute quantification capability enabled dynamic monitoring of EBV load in NPC patients during initial diagnosis, treatment, and recurrence, thereby potentially improving disease management and prognosis. Taken together, our results demonstrate that this amplification-free digital assay has the potential to be a robust tool to improve the diagnosis and surveillance of NPC. • Dual-crRNAs targeting the repetitive sequences of EBV DNA. • Cis -cleavage activity of Cas12a prior to compartmentalization. • Robust quantification without amplification or reference materials. • Validated by a case-control study (n = 208). • A promising alternative to current PCR-based EBV DNA testing. [ABSTRACT FROM AUTHOR]

Simplicity, sensitivity and high throughput are the qualities researcher always difficultly pursue in the screening surveillance assay for food contaminants. Herein, coupled with a common gel imager as a signal reader, a novel magnet-actuated droplet microfluidic immunosensor without any complicated manipulation system was successfully fabricated for the convenient and sensitive detection of cyanobacteria toxin microcystin-LR (MC-LR) in aquatic products. The proposed sensor demonstrated three superiorities compared to the extensively used microfluidic systems: 1) simple but effective operation only by magnetic force rather than inconvenient actuating devices; 2) high throughput parallel detection on a 15-channels chip; 3) convenient signal readout on an ordinary laboratorial gel imager. This gel imager-assisted magnet-actuated droplet microfluidic immunosensor exhibited a limit of detection as low as 6.0 × 10−4 μg/L with high specificity. The average recoveries were ranged from 92.0% to 96.6% in spiked fish and prawn samples, and showed a good agreement with confirmation method LC-MS/MS, suggesting the proposed method to be an ideal surveillance assay tool for the MC-LR monitoring in aquatic products. Image 1 • A novel magnet-actuated droplet microfluidic immunosensor allow high throughput parallel detection was developed. • A novel magnet-actuated droplet microfluidic immunosensor allow high throughput parallel detection was developed. • Convenient signal readout on a common laboratorial gel imager. [ABSTRACT FROM AUTHOR]