Macro aerodynamic devices controlled by micro systems

Micro-ElectroMechanical-Systems (MEMS) have emerged as a major enabling technology across the engineering disciplines. In this study, the possibility of applying MEMS to the aerodynamic field was explored. We have demonstrated that microtransducers can be used to control the motion of a delta wing in a wind tunnel and can even maneuver a scaled aircraft in flight tests. The main advantage of using micro actuators to replace the traditional control surface is the significant reduction of radar cross-sections. At a high angle of attack, a large portion of the suction loading on a delta wing is contributed by the leading edge separation vortices which originate from thin boundary layers at the leading edge. We used microactuators with a thickness comparable to that of the boundary layer in order to alter the separation process and thus achieved control of the global motion by minute perturbations

Miniature RT–PCR system for diagnosis of RNA-based viruses

This paper presents an innovative portable chip-based RT–PCR system for amplification of specific nucleic acid and detection of RNA-based viruses. The miniature RT–PCR chip is fabricated using MEMS (Micro-electro-mechanical-system) techniques, and comprises a micro temperature control module and a PDMS (polydimethylsiloxane)-based microfluidic control module. The heating and sensing elements of temperature control module are both made of platinum and are located within the reaction chambers in order to generate a rapid and uniform thermal cycling. The microfluidic control module is capable of automating testing process with minimum human intervention. In this paper, the proposed miniature RT–PCR system is used to amplify and detect two RNA-based viruses, namely dengue virus type-2 and enterovirus 71 (EV 71). The experimental data confirm the ability of the system to perform a two-step RT–PCR process. The developed miniature system provides a crucial tool for the diagnosis of RNA-based viruses

Droplet microreactor for reaction monitoring at elevated temperatures and pressure

Recording reaction kinetics in detail and at various reaction conditions can be a time-consuming process. Microdroplets form ideal reaction chambers, suitable for high-throughput studies [1]. We report the fabrication of a microfluidic droplet-based microreactor operating at elevated temperatures (up to 130 °C) and pressures (up to 0.7 MPa), to rapidly study reaction kinetics. As proof-of-principle, the temperature-dependent fluorescence of Rhodamine B in ethanol is monitored [2]. Time-resolved information is obtained by measuring at multiple spots in the microreacto

Nervous Necrosis Virus Replicates Following the Embryo Development and Dual Infection with Iridovirus at Juvenile Stage in Grouper

Infection of virus (such as nodavirus and iridovirus) and bacteria (such as Vibrio anguillarum) in farmed grouper has been widely reported and caused large economic losses to Taiwanese fish aquaculture industry since 1979. The multiplex assay was used to detect dual viral infection and showed that only nervous necrosis virus (NNV) can be detected till the end of experiments (100% mortality) once it appeared. In addition, iridovirus can be detected in a certain period of rearing. The results of real-time PCR and in situ PCR indicated that NNV, in fact, was not on the surface of the eggs but present in the embryo, which can continue to replicate during the embryo development. The virus may be vertically transmitted by packing into eggs during egg development (formation) or delivering into eggs by sperm during fertilization. The ozone treatment of eggs may fail to remove the virus, so a new strategy to prevent NNV is needed

Molecular Diagnosis of Periprosthetic Joint Infection by Quantitative RT-PCR of Bacterial 16S Ribosomal RNA

The diagnosis of periprosthetic joint infection is sometimes straightforward with purulent discharge from the fistula tract communicating to the joint prosthesis. However it is often difficult to differentiate septic from aseptic loosening of prosthesis because of the high culture-negative rates in conventional microbiologic culture. This study used quantitative reverse transcription polymerase chain reaction (RT-qPCR) to amplify bacterial 16S ribosomal RNA in vitro and in 11 clinical samples. The in vitro analysis demonstrated that the RT-qPCR method was highly sensitive with the detection limit of bacterial 16S rRNA being 0.148 pg/μl. Clinical specimens were analyzed using the same protocol. The RT-qPCR was positive for bacterial detection in 8 culture-positive cases (including aerobic, anaerobic, and mycobacteria) and 2 culture-negative cases. It was negative in one case that the final diagnosis was confirmed without infection. The molecular diagnosis of bacterial infection using RT-qPCR to detect bacterial 16S rRNA around a prosthesis correlated well with the clinical findings. Based on the promising clinical results, we were attempting to differentiate bacterial species or drug-resistant strains by using species-specific primers and to detect the persistence of bacteria during the interim period before the second stage reimplantation in a larger scale of clinical subjects

Human induced pluripotent stem cell-derived endothelial cells in thrombosis-on-a-chip devices

A microfluidic thrombosis-on-a-chip platform was developed to compare the pro-thrombotic response of healthy and inflamed monolayers of human umbilical vein endothelial cells (HUVECs) and human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs). Inflammation was induced by exposing the endothelial cells (ECs) to an inflammatory cytokine Tumor Necrosis Factor-α (TNF-α). After human whole blood perfusion at an arterial shear rate, the platelet coverage and average clot size were determined. Healthy endothelium showed a lower platelet coverage than inflamed endothelium. A minor difference was measured for both platelet coverage and average clot sizes on inflamed HUVECs versus hiPSC-ECs

Standardized, Modular Parallelization Platform for Microfluidic Large-Scale Integration Cell Culturing Chips

Standardized high-throughput devices for microfluidic cell cultures are necessary to translate discoveries made in academia to applications in pharmaceutical industry. Here we present a platform with integrated pneumatic valves for standardized parallelization of multichamber chips (SPARC). In total, 192 chambers divided over three microfluidic building blocks (MFBBs) can be filled and purged with spatial and temporal independence. The dimensions of both the MFBB and the platform are standardized and thus compatible with common lab equipment. We characterize the valves at different pumping and gate pressures and show that the MFBBs are suitable for culturing human umbilical vein endothelial cells (HUVECs)