Micro Materials (United Kingdom)

Antimicrobial resistance poses a major global health threat, often driven by empirical antibiotic use due to the relatively slow (24-72 h) diagnostic pathway for urinary tract infections (UTIs). Due to their low cost and ease of multiplexing, electrochemical biosensors offer a promising alternative. Herein, we report on the Microplate Dx RapidPlate platform, a rapid electrochemical impedance spectroscopy (EIS)-based approach for accelerated antibiotic susceptibility testing (AST) directly from urine samples, without pre-treatment. This report charts the evolution of the core EIS-based AST measurement from a laboratory prototype into a fully realized Alpha prototype platform with an accompanying 32-channel electrochemical cartridge designed specifically for interrogation of urine samples. A total of 89 clinically derived urine samples were evaluated at three clinical sites (U.K. and India), with results compared against standard methods (VITEK 2 and disk diffusion). The impedance-based RapidPlate system detected bacterial growth within 50 min and provided susceptibility profiles by 85 min, with 95% concordance to reference tests. Consistent performance was demonstrated across diverse clinical settings and organisms, including Escherichia coli and Klebsiella pneumoniae. The RapidPlate AST system has demonstrated great potential as a cost-effective, point-of-care tool for rapid AST, supporting and improving UTI management and antimicrobial stewardship.

The thermo-mechanical reliability of an industrial power module containing IGBTs with soldered die and module attachment and aluminum bonding wires has been investigated. In this kind of power packaging, die attachment, module attachment, and bonding wires attachment can be critical failure modes. It was one aim of the investigation to analyze these failures when the modules are subjected to different kinds of passive and power cycling. Furthermore, prediction of these failures based on finite element (FE) studies are addressed. Coupled (FE-) analyses are reported to understand the thermo-mechanical stresses in the assembly. Verification of evaluation methodologies to predict cyclic damage are in the focus of the paper. Physics-of-failure (PoF) based lifetime prediction is applied for a power stack die attach with soft solder between chip and substrate and between substrate and base-plate. An easy-to-use Coffin-Manson type failure criterion is given based on averaged cyclic creep strain and dissipation density. At the wire bonding interfaces bi-material notch effects cause stronger interface stress singularity, and therefore, damage mechanics criteria already proposed in are updated and applied. Cyclic damage is calculated by the Cohesive Zone Method (CZM) and critical cycle numbers are estimated from that by a modified Paris law. The predictive laws for both thin solder layers and heavy Al bonds are compared to testing results and shown to agree well.

The reinforcement function of shell ribs depends not only on their vaulted morphology but also on their microstructure. They are part of the outer layer which, in the case of the Pinna nobilis bivalve, is built from almost monocrystalline calcitic prisms, always oriented perpendicular to the growth surfaces. Originally, prisms and their c-axes follow the radii of rib curvature, becoming oblique to the shell thickness direction. Later, prisms bend to reach the nacre layer perpendicularly, but their c-axes retain the initial orientation. Calcite grains form nonrandom boundaries. Most often, three twin disorientations arise, with two of them observed for the first time. Nano-indentation and impact tests demonstrate that the oblique orientation of c-axes significantly improves the hardness and fracture toughness of prisms. Moreover, compression tests reveal that the rib area achieves a unique strength of 700 MPa. The detection of the specific microstructure formed to toughen the shell is novel.

In this paper, the research is focused on lifetime analysis and prediction of silver sintered power devices by experiment and numerical simulation. As researches are emerging on the field of lead-free interconnect technology, silver sintering become an alternative interconnect technology to standard solders. This technology differs from other interconnect technologies because of it’s improved thermal and mechanical properties. Aluminum cladded copper core (CucorAl) wires have been used to prevent early fail of top contacts. Material degradation due to thermal fatigue in the sintered silver still influences the reliability in the interconnect, in particular for high temperature swings upcoming with wide bandgap semiconductors. Plastic deformation is observed in sintered silver interconnect which depends on time and temperature. This research work presents combined experimental and finite element analysis (FEA) results for developing a lifetime model for the sintered silver power modules. Different parameters such as porosities on the sintered silver layer, substrates, plastic and creep constitutive laws, die thickness and sizes, should be considered during the development of lifetime model. In this investigation, Insulated-gate bipolar transistor (IGBT) chips are integrated on different substrates such as printed circuit board (PCB- Help H), insulated metal substrate (IMS), copper lead frame (Cu-lead frame) and direct copper bond (DCB) by silver sintered interconnect. Failure modes such as wire bond lift-off and die bond degradation are observed during this research.

Synthesis of flower-shaped ZnO nanostructures composed of hexagonal ZnO nanorods was achieved by the solution process using zinc acetate dihydrate and sodium hydroxide at very low temperature of 90 8C in 30 min. The individual nanorods are of hexagonal shape with sharp tip, and base diameter of about 300–350 nm. Detailed structural characterizations demonstrate that the synthesized products are single crystalline with the wurtzite hexagonal phase, grown along the [0 0 0 1] direction. The IR spectrum shows the standard peak of zinc oxide at 523 cm-1. Raman scattering exhibits a sharp and strong E2 mode at 437 cm-1 which further confirms the good crystallinity and wurtzite hexagonal phase of the grown nanostructures. The photoelectron spectroscopic measurement shows the presence of Zn, O, C, zinc acetate and Na. The binding energy ca. 1021.2 eV (Zn 2p3/2) and 1044.3 eV (Zn 2p1/2), are found very close to the standard bulk ZnO binding energy values. The O 1s peak is found centered at 531.4 eV with a shoulder at 529.8 eV. Room-temperature photoluminescence (PL) demonstrate a strong and dominated peak at 381 nm with a suppressed and broad green emission at 515 nm, suggests that the flower-shaped ZnO nanostructures have good optical properties with very less structural defects.