Focused ion beam (FIB) prepared microtextured microneedle array capable of delivering drugs through punctured skin.

Microtextured microneedles are tiny needle-like structures with micron-scale microtextures, and the drugs stored in the microtextures can be released after entering the skin to achieve the effect of precise drug delivery. In this study, the skin substitution model of Ogden's hyperelastic model and the microneedle array and microtexture models with different geometrical parameters were selected to simulate and analyse the flow of the microtexture microneedle arrays penetrating the skin by the finite-element method, and the length of the microneedles was determined to be 200 μm, the width 160 μm, and the value of the gaps was determined to be 420 μm. A four-pronged cone was chosen as the shape of microneedles, and a rectangle was chosen as the shape of the drug-carrying microneedle.

Sensitivity-Enhancing Strategies of Graphene Field-Effect Transistor Biosensors for Biomarker Detection.

The ultrasensitive recognition of biomarkers plays a crucial role in the precise diagnosis of diseases. Graphene-based field-effect transistors (GFET) are considered the most promising devices among the next generation of biosensors. GFET biosensors possess distinct advantages, including label-free, ease of integration and operation, and the ability to directly detect biomarkers in liquid environments.

Effect of interface layer on the enhancement of thermal conductivity of SiC-Water nanofluids: Molecular dynamics simulation.

To investigate the impact of interfacial layer effects on the thermal conductivity of nanofluids and the microscopic mechanisms of enhanced thermal conductivity, this study employed non-equilibrium molecular dynamics to compute the thermal conductivity, number density, radial distribution function, and mean square displacement distribution of SiC nanofluids. The impact of nanoparticle volume fraction and particle size parameters on the thermal conductivity of nanofluids and the structure of interfacial adsorption layers was discussed. The simulation calculation results show that the coefficient of thermal conductivity of nanofluid is positively related to the volume fraction of nanoparticles, increasing from 0.

MC design and FIB preparation of a YSZ biochemical material microstructure.

Aiming at the difficulty of traditional machining of YO-ZrO (YSZ) inert ceramic materials, a different method using focused ion beam to selectively create nanoscale microscale structures on the surface of materials was proposed. The sputtering yield, surface damage, and the energy loss of YSZ materials was investigated using the SRIM software using the Monte Carlo method. It is shown that the sputtering yield increases with ion energy in the range 0-30 keV, reaching a maximum of 9.

Effect of Al Content on the Wear Evolution of TiAlN-Coated Tools Milling Ti-6Al-4V Alloy.

TiAlN coating is formed by replacing some Ti atoms in TiN with Al atoms, and their properties are closely related to Al content (0 < x < 1). Recently, TiAlN-coated tools have been widely used in the machining of Ti-6Al-4V alloy. In this paper, the hard-to-machine material Ti-6Al-4V alloy is used as the study material.

Accurate Cutting-Force Measurement with Smart Tool Holder in Lathe.

Cutting force in lathe work is closely related to tool wear and affects the turning quality. Direct measurement of the cutting force by measuring the strain of the tool holder is challenging because the tool holder design aims to be highly rigid in order to undertake large cutting forces. Accordingly, the most popular dynamometer designs modify the standard tool holder by decreasing the structural rigidity of the holder, which reduces the machining precision and is not widely accepted.

Experimental Research and Numerical Simulation of Laser Welding of 303Cu/440C-Nb Stainless-Steel Thin-Walled Natural-Gas Injector for Vehicles.

This paper presents the results of research on laser lap welding technology of heterogeneous materials and a laser post-heat treatment method to enhance welding performance. The purpose of this study is to reveal the welding principle of austenitic/martensitic dissimilar stainless-steel materials (3030Cu/440C-Nb) and to further obtain welded joints with good mechanical and sealing properties. A natural-gas injector valve is taken as the study case where its valve pipe (303Cu) and valve seat (440C-Nb) are welded.

Gut-on-a-chip for exploring the transport mechanism of Hg(II).

Animal models and static cultures of intestinal epithelial cells are commonly used platforms for exploring mercury ion (Hg(II)) transport. However, they cannot reliably simulate the human intestinal microenvironment and monitor cellular physiology in situ; thus, the mechanism of Hg(II) transport in the human intestine is still unclear. Here, a gut-on-a-chip integrated with transepithelial electrical resistance (TEER) sensors and electrochemical sensors is proposed for dynamically simulating the formation of the physical intestinal barrier and monitoring the transport and absorption of Hg(II) in situ.

Addition of Nano CaF@SiO and SiC Whiskers in Ceramic Tools for Wear Reduction and Improved Machinability.

The addition of CaF@SiO and SiC whiskers to ceramic tools can improve their flexural strength and fracture toughness, reduce surface damage, and improve their cutting performance. The cutting experiments showed that under the same cutting conditions, the surface roughness of the workpiece processed with the AlO/TiC/SiC/CaF@SiO (ATSC10) tool was significantly lower than that of the workpiece processed with the AlO/TiC/ SiC (ATS) tool. Additionally, the main cutting force and cutting temperature when cutting with the ATSC10 tool were lower by 30 and 31.

Crack Sensing of Cardiomyocyte Contractility with High Sensitivity and Stability.

Measuring myocardial contractility is of great value in exploring cardiac pathogenesis and quantifying drug efficacy. Among the biosensing platforms developed for detecting the weak contractility of a single layer of cardiomyocytes (CMs), thin brittle metal membrane sensors with microcracks are highly sensitive. However, their poor stability limits the application in long-term measurement.

Green Manufacturing of Flexible Sensors with a Giant Gauge Factor: Bridging Effect of CNT and Electric Field Enhancement at the Percolation Threshold.

Toxic organic solvents are commonly used to disperse nanomaterials in the manufacturing of flexible conductive composites (e.g., graphene-PDMS).

Modelling and Prediction of Cutting Temperature in the Machining of H13 Hard Steel of Transient Heat Conduction.

Cutting heat conduction undergoes three stages that include intensity transient-state, transient-state, and steady-states. Especially during machining with coated cutting tools, in the conduction process, cutting heat needs to pass through a few micron thick coatings and then flow into the tool body. This heat conduction presents typical non-Fourier heat conduction characteristics.

Electrochemical biosensors for measurement of colorectal cancer biomarkers.

Colorectal cancer (CRC) is associated with one of the highest rates of mortality among cancers worldwide. The early detection and management of CRC is imperative. Biomarkers play an important role in CRC screening tests, CRC treatment, and prognosis and clinical management; thus rapid and sensitive detection of biomarkers is helpful for early detection of CRC.

Effect of the Characteristic Size and Content of Graphene on the Crack Propagation Path of Alumina/Graphene Composite Ceramics.

In this paper, the Voronoimosaic model and the cohesive element method were used to simulate crack propagation in the microstructure of alumina/graphene composite ceramic tool materials. The effects of graphene characteristic size and volume content on the crack propagation behavior of microstructure model of alumina/graphene composite ceramics under different interfacial bonding strength were studied. When the phase interface is weak, the average energy release rate is the highest as the short diameter of graphene is 10-50 nm and the long diameter is 1600-2000 nm.

A CNT-PDMS wearable device for simultaneous measurement of wrist pulse pressure and cardiac electrical activity.

Simultaneous measurement of multi-physiological signals can provide effective diagnosis and therapeutic assessment of diseases. This paper reports a carbon nanotube (CNT) - Polydimethylsiloxane (PDMS) - based wearable device with piezo-resistive and voltage-sensing capabilities for simultaneously capturing wrist pulse pressure and cardiac electrical signal. The layout design of sensing elements in the device was guided by analyzing strain distribution and electric field distribution for minimizing the interference between wrist pulse and cardiac electric activity during measurement.

Influence of CaF@AlO on Cutting Performance and Wear Mechanism of AlO/Ti(C,N)/CaF@AlO Self-Lubricating Ceramic Tools in Turning.

This study aimed at improving the cutting performance of a ceramic tool to which were added solid lubricant particles. We prepared the self-lubricating ceramic tool by adding CaF@AlO instead of CaF, and the self-lubricating ceramic tool with AlO as matrix phase, Ti(C,N) as reinforcement phase. The properties of the ceramic tool with different contents of CaF@AlO and CaF were studied by turning 40Cr.

Synthesis and Mechanical Characterization of a Ti(C,N)/Mo-Co-Ni/CaF@AlO Self-Lubricating Cermet.

In this paper, an AlO coated CaF (CaF@AlO) nanocomposite powder is used as the additive phase of a Ti(C,N)-based self-lubricating cermet material. A novel self-lubricating ceramic material with a multilayer core-shell microstructure was prepared using a vacuum hot-pressing sintering process. The results show that the surface of the CaF powder is coated with AlO, and when introduced into a Ti(C,N)-Mo-Co-Ni material system, it can utilize the high-temperature liquid phase diffusion mechanism of the metal Mo-Co-Ni phase in the sintering process.

Preparation of AlO/Ti(C,N)/ZrO/CaF@Al(OH) Ceramic Tools and Cutting Performance in Turning.

Aiming at the contradiction between the lubricating performance and mechanical performance of self-lubricating ceramic tools. CaF@Al(OH) particles were prepared by the heterogeneous nucleation method. An AlO/Ti(C,N) ceramic tool with CaF@Al(OH) particles and ZrO whiskers was prepared by hot press sintering (frittage).

Synthesis of CaF Nanoparticles Coated by SiO for Improved AlO/TiC Self-Lubricating Ceramic Composites.

In order to reduce the influence of CaF addition on the mechanical properties of self-lubricating ceramic tools, we applied a silicon dioxide (SiO) coating on calcium fluoride (CaF) nanoparticles through hydrolysis and condensation reactions using the tetraethoxysilane (TEOS) method. The powder was dried by the azeotropic method, so that it acquired a better dispersibility. The resulting composite powders were characterized using XRD (X-ray diffraction) and TEM (transmission electron microscopy), showing that the surface of CaF was coated with a layer of uniform and compact SiO.

Lubrication Performance of Graphene as Lubricant Additive in 4-n-pentyl-4'-cyanobiphyl Liquid Crystal (5CB) for Steel/Steel Contacts.

The lubrication performance of graphene used as additive in 4-n-pentyl-4'-cyanobiphyl liquid crystal (5CB) for steel/steel contacts was studied on a ball-on-plate tribotester. The friction test results show that when the graphene content in the 5CB was 0.15 wt.