Elevated Blood Viscosity and Microrecirculation Resulting From Coronary Stent Malapposition.

One particular complexity of coronary artery is the natural tapering of the vessel with proximal segments having larger caliber and distal tapering as the vessel get smaller. The natural tapering of a coronary artery often leads to proximal incomplete stent apposition (ISA). ISA alters coronary hemodynamics and creates pathological path to develop complications such as in-stent restenosis, and more worryingly, stent thrombosis (ST). By employing state-of-the-art computer-aided design software, generic stent hoops were virtually deployed in an idealized tapered coronary artery with decreasing malapposition distance. Pulsatile blood flow simulations were carried out using computational fluid dynamics (CFD) on these computer-aided design models. CFD results reveal unprecedented details in both spatial and temporal development of microrecirculation environments throughout the cardiac cycle (CC). Arterial tapering also introduces secondary microrecirculation. These primary and secondary microrecirculations provoke significant fluctuations in arterial wall shear stress (WSS). There has been a direct correlation with changes in WSS and the development of atherosclerosis. Further, the presence of these microrecirculations influence strongly on the local levels of blood viscosity in the vicinity of the malapposed stent struts. The observation of secondary microrecirculations and changes in blood rheology is believed to complement the wall (-based) shear stress, perhaps providing additional physical explanations for tissue accumulation near ISA detected from high resolution optical coherence tomography (OCT).

A Smart CMOS Assay SoC for Rapid Blood Screening Test of Risk Prediction.

A micro-controller unit (MCU) assisted immunoassay lab-on-a-chip is realized in 0.35 µm CMOS technology. The MCU automatically controls the detection procedure including blood filtration through a nonporous aluminum oxide membrane, bimolecular conjugation with antibodies attached to magnetic beads, electrolytic pumping, magnetic flushing and threshold detection based on Hall sensor array readout analysis. To verify the function of this chip, in-vitro Tumor necrosis factor- α (TNF-α) and N-terminal pro-brain natriuretic peptide (NT-proBNP) tests are performed by this 9 mm(2)-sized single chip. The cost, efficiency and portability are considerably improved compared to the prior art.

A remotely-controlled locomotive IC driven by electrolytic bubbles and wireless powering.

A batteryless remotely-controlled locomotive IC utilizing electrolytic bubbles as propelling force is realized in 0.35 µm CMOS technology. Without any external components, such as magnets and on-board coils, the bare IC is wirelessly powered and controlled by a 10 MHz ASK modulated signal with RS232 control commands to execute movement in four moving directions and with two speeds. The receiving coil and electrolysis electrodes are all integrated on the locomotive chip. The experiment successfully demonstrated that the bare IC moved on the surface of an electrolyte with a speed up to 0.3 mm/s and change moving directions according to the commands. The total power consumptions of the chip are 207.4 µW and 180 µ W while the output electrolysis voltages are 2 V and 1.3 V, respectively.

Non-invasive Drosophila ECG recording by using eutectic gallium-indium alloy electrode: a feasible tool for future research on the molecular mechanisms involved in cardiac arrhythmia.

BACKGROUND: Drosophila heart tube is a feasible model for cardiac physiological research. However, obtaining Drosophila electrocardiograms (ECGs) is difficult, due to the weak signals and limited contact area to apply electrodes. This paper presents a non-invasive Gallium-Indium (GaIn) based recording system for Drosophila ECG measurement, providing the heart rate and heartbeat features to be observed. This novel, high-signal-quality system prolongs the recording time of insect ECGs, and provides a feasible platform for research on the molecular mechanisms involved in cardiovascular diseases. METHODS: In this study, two types of electrode, tungsten needle probes and GaIn electrodes, were used respectively to noiselessly conduct invasive and noninvasive ECG recordings of Drosophila. To further analyze electrode properties, circuit models were established and simulated. By using electromagnetic shielded heart signal acquiring system, consisted of analog amplification and digital filtering, the ECG signals of three phenotypes that have different heart functions were recorded without dissection. RESULTS AND DISCUSSION: The ECG waveforms of different phenotypes of Drosophila recorded invasively and repeatedly with n value (n>5) performed obvious difference in heart rate. In long period ECG recordings, non-invasive method implemented by GaIn electrodes acts relatively stable in both amplitude and period. To analyze GaIn electrode, the correctness of GaIn electrode model established by this paper was validated, presenting accuracy, stability, and reliability. CONCLUSIONS: Noninvasive ECG recording by GaIn electrodes was presented for recording Drosophila pupae ECG signals within a limited contact area and signal strength. Thus, the observation of ECG changes in normal and SERCA-depleted Drosophila over an extended period is feasible. This method prolongs insect survival time while conserving major ECG features, and provides a platform for electrophysiological signal research on the molecular mechanism involved in cardiac arrhythmia, as well as research related to drug screening and development.