A portable multifunctional power box

In this study, we used a microcontroller to provide and control power to multiple sources using the highly efficient energy storage provided by the direct current (DC) bus of a lithium iron phosphate (LiFePO₄) battery. Through multiple loops, high-efficiency buck and boost conversion, and DC-to-alternating current (AC) conversion, the power box can quickly and simultaneously provide three sets of voltage outputs, 5-V DC, 19–22-V DC, and 110-V AC, to different electronic devices. Multiple sets of conversion output voltages were achieved using multiple sets of conversion circuits, in parallel to the DC bus. Compared with a single conversion output voltage, the multiple sets of conversion output voltages from the energy storage battery had a higher practicability. For a single output voltage, the battery provided a suitable voltage to different electric devices via a substage converter, thus lowering the overall conversion efficiency. For practical applications such as camping, blackouts, long journeys, emergencies, and rescues, the multiple sets of converted voltage outputs offer substantial functional convenience. For safety control, we used a single-chip controller to quickly detect various overcurrent situations.     

Effect of stents coated with a combination of sirolimus and alpha-lipoic acid in a porcine coronary restenosis model

The aim of this study was to evaluate antiproliferative sirolimus- and antioxidative alpha-lipoic acid (ALA)-eluting stents using biodegradable polymer [poly-l-lactic acid (PLA)] in a porcine coronary overstretch restenosis model. Forty coronary arteries of 20 pigs were randomized into four groups in which the coronary arteries had a bare metal stent (BMS, n = 10), ALA-eluting stent with PLA (AES, n = 10), sirolimus-eluting stent with PLA (SES, n = 10), or sirolimus- and ALA-eluting stent with PLA (SAS, n = 10). A histopathological analysis was performed 28 days after the stenting. The ALA and sirolimus released slowly over 30 days. There were no significant differences between groups in the injury or inflammation score; however, there were significant differences in the percent area of stenosis (56.2 ± 11.78 % in BMS vs. 51.5 ± 12.20 % in AES vs. 34.7 ± 7.23 % in SES vs. 28.7 ± 7.30 % in SAS, P < 0.0001) and fibrin score [1.0 (range 1.0–1.0) in BMS vs. 1.0 (range 1.0–1.0) in AES vs. 2.0 (range 2.0–2.0) in SES vs. 2.0 (range 2.0–2.0) in SAS, P < 0.0001] between the four groups. The percent area of stenosis based on micro-computed tomography corresponded with the restenosis rates based on histopathological stenosis in different proportions in the four groups (54.8 ± 7.88 % in BMS vs. 50.4 ± 14.87 % in AES vs. 34.5 ± 7.22 % in SES vs. 28.9 ± 7.22 % in SAS, P < 0.05). SAS showed a better neointimal inhibitory effect than BMS, AES, and SES at 1 month after stenting in a porcine coronary restenosis model. Therefore, SAS with PLA can be a useful drug combination for coronary stent coating to suppress neointimal hyperplasia.     

Electromigration effect on Sn-58 % Bi solder joints with various substrate metallizations under current stress

The electromigration behavior of low-melting temperature Sn-58Bi (in wt%) solder joints was investigated with a high current density between 3 and 4.5 × 10³ A/cm² between 80 and 110 °C. In order to analyze the impact of various substrate metallizations on the electromigration performance of the Sn-58Bi joint, we used representative substrate metallizations including electroless nickel immersion gold (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG), and organic solderability preservatives (OSP). As the applied current density increased, the time to failure (TTF) for electromigration decreased regardless of the temperature or substrate metallizations. In addition, the TTF slightly decreased with increasing temperature. The substrate metallization significantly affected the TTF for the electromigration behavior of the Sn-58Bi solder joints. The substrate metallizations for electromigration performance of the Sn-58Bi solder are ranked in the following order: OSP-Cu, ENEPIG, and ENIG. Due to the polarity effect, current stressing enhanced the fast growth of intermetallic compounds (IMCs) at the anode interface. Cracks occurred at the Ni₃Sn₄ + Ni₃P IMC/Cu interfaces on the cathode sides in the Sn-58Bi/ENIG joint and the Sn-58Bi/ENEPIG joint; this was caused by the complete consumption of the Ni(P) layer. Alternatively, failure occurred via deformation of the bulk solder in the Sn-58Bi/OSP-Cu joint. The experimental results confirmed that the electromigration reliability of the Sn-58Bi/OSP-Cu joint was superior to those of the Sn-58Bi/ENIG or Sn-58Bi/ENEPIG joints.     

Autonomous Magnetic Microrobots by Navigating Gates for Multiple Biomolecules Delivery

The precise delivery of biofunctionalized matters is of great interest from the fundamental and applied viewpoints. In spite of significant progress achieved during the last decade, a parallel and automated isolation and manipulation of rare analyte, and their simultaneous on‐chip separation and trapping, still remain challenging. Here, a universal micromagnet junction for self‐navigating gates of microrobotic particles to deliver the biomolecules to specific sites using a remote magnetic field is described. In the proposed concept, the nonmagnetic gap between the lithographically defined donor and acceptor micromagnets creates a crucial energy barrier to restrict particle gating. It is shown that by carefully designing the geometry of the junctions, it becomes possible to deliver multiple protein‐functionalized carriers in high resolution, as well as MCF‐7 and THP‐1 cells from the mixture, with high fidelity and trap them in individual apartments. Integration of such junctions with magnetophoretic circuitry elements could lead to novel platforms without retrieving for the synchronous digital manipulation of particles/biomolecules in microfluidic multiplex arrays for next‐generation biochips.     

Highly Uniform Resistive Switching Properties of Solution‐Processed Silver‐Embedded Gelatin Thin Film

The silver‐embedded gelatin (AgG) thin film produced by the solution method of metal salts dissolved in gelatin is presented. Its simple fabrication method ensures the uniform distribution of Ag dots. Memory devices based on AgG exhibit good device performance, such as the ON/OFF ratio in excess of 10⁵ and the coefficient of variation in less of 50%. To further investigate the position of filament formation and the role of each element, current sensing atomic force microscopy (CSAFM) analysis as well as elemental line profiles across the two different conditions in the LRS and HRS are analyzed. The conductive and nonconductive regions in the current map of the CSAFM image show that the conductive filaments occur in the AgG layer around Ag dots. The migration of oxygen ions and the redox reaction of carbon are demonstrated to be the driving mechanism for the resistive switching of AgG memory devices. The results show that dissolving metal salts in gelatin is an effective way to achieve high‐performance organic–electronic applications.