Realization of long-range magnetic order in surface-supported two-dimensional systems has been challenging, mainly due to the competition between fundamental magnetic interactions as the short-range Kondo effect and spin-stabilizing magnetic exchange interactions. Spin-bearing molecules on conducting substrates represent a rich platform to investigate the interplay of these fundamental magnetic interactions. Here we demonstrate the direct observation of long-range ferrimagnetic order emerging in a two-dimensional supramolecular Kondo lattice. The lattice consists of paramagnetic hexadeca-fluorinated iron phthalocyanine (FeFPc) and manganese phthalocyanine (MnPc) molecules co-assembled into a checkerboard pattern on single-crystalline Au(111) substrates. Remarkably, the remanent magnetic moments are oriented in the out-of-plane direction with significant contribution from orbital moments. First-principles calculations reveal that the FeFPc-MnPc antiferromagnetic nearest-neighbour coupling is mediated by the Ruderman–Kittel–Kasuya–Yosida exchange interaction via the Au substrate electronic states. Our findings suggest the use of molecular frameworks to engineer novel low-dimensional magnetically ordered materials and their application in molecular quantum devices.
Three‐dimensional (3D) microtissues, cultured in microfluidic platforms, enable to study complex biological mechanisms that cannot be replicated in two‐dimensional cell cultures. Deeper insights can be obtained if these 3D culture systems are rendered compatible with high‐resolution time‐lapse imaging systems, which requires precise placement and immobilization of the specimen while ensuring high viability and functionality of the 3D cell constructs. This article presents a versatile microfluidic platform for long‐term culturing and analysis of 3D microtissues. The platform is compatible with time‐lapse high‐resolution confocal microscopy. Hanging hydrogel drops enable the precise placement and stable immobilization of the microtissues in the microfluidic chip. The chip includes perfusion capability to apply drugs, staining and clearing solutions. The features of the chip are demonstrated by studying (i) colon cancer microtissues to monitor tissue growth and cell death; on‐chip clearing was used to augment the penetration depth for endpoint imaging; (ii) primary human liver microtissues were exposed to cytochalasin D to observe its effect on the bile canaliculi. The results obtained with both sample types demonstrate the suitability of the system for investigating complex processes in organotypic 3D microtissues, down to single‐cell level, and for observation of physiologically relevant processes at subcellular scale.
Dielectric elastomer actuator (DEA) micro- and nano-structures are referred to artificial muscles because of their specific continuous power and adequate time response. The bending measurement of an asymmetric, planar DEA is described. The asymmetric cantilevers consist of 1 or 5 μm-thin DEAs deposited on polyethylene naphthalate (PEN) substrates 16, 25, 38, or 50 μm thick. The application of a voltage to the DEA electrodes generates an electrostatic pressure in the sandwiched silicone elastomer layer, which causes the underlying PEN substrate to bend. Optical beam deflection enables the detection of the bending angle vs. applied voltage. Bending radii as large as 850 m were reproducibly detected. DEA tests with electric fields of up to 80 V/μm showed limitations in electrode's conductivity and structure failures. The actuation measurement is essential for the quantitative characterization of nanometer-thin, low-voltage, single- and multi-layer DEAs, as foreseen for artificial sphincters to efficiently treat severe urinary and fecal incontinence.
The worldwide outbreak of COVID-19 has drastically increased pressure on medical resources and highlighted the need for rapidly available, large-scale, and low-cost personal protective equipment (PPE). In this work, an alternative full-face mask is adapted from a modified snorkel mask to be used as PPE with two medical-grade filters and a 3D-printed adapter. Since the mask covers the eyes, mouth, and nose, it acts as a full-face shield, providing additional protection to healthcare workers. The SARS-CoV-2 has a size between 60 nm and 140 nm, and airborne viral particles can be carried by larger droplets with sizes up to several millimeters. The minimum filtration efficiency of mechanical and electrostatic filters is usually reached between 30 nm and 300 nm. The filtration efficiency of different medical filters is measured for particles below 300 nm to cover the size of the SARS-CoV-2 and small virus-laden droplets, and determine the minimum efficiency. The filtration performance of the adapted full-face mask is characterized using NaCl particles below 500 nm and different fitting scenarios to determine the minimum protection efficiency. The mask is compared to a commercial respirator and characterized according to the EN 149 standard, demonstrating that the protection fulfills the requirements for the FFP2 level (filtering face-piece 2, stopping at least 94% of airborne particles). The device shows a good resistance to several cycles of decontamination (autoclaving and ethanol immersion), is easy to be produced locally at low cost, and helps to address the shortage in FFP2 masks and face shields by providing adequate protection to healthcare workers against particles <500 nm in size.
The worldwide outbreak of the COVID-19 drastically increased pressure on medical resources and highlighted the need for rapidly available, large-scale and low-cost personal protective equipment (PPE). In this work, an alternative full-face mask is adapted from a modified snorkel mask to be used as PPE with two medical grade filters and a 3D-printed adapter. As the mask covers the eyes, mouth and nose, it acts as a full-face shield, providing additional protection to healthcare workers. The filtration efficiency of different medical filters is measured for particles below 300 nm to cover the size of the SARS-CoV-2 and small virus-laden droplets. The filtration performance of the adapted full-face mask is characterized using NaCl particles below 500 nm and different fitting scenarios. The mask is compared to a commercial respirator and characterized according to the EN 149 standard, demonstrating that the protection fulfills the requirements for the FFP2 level (filtering face-piece 2, stopping at least 94% of airborne particles). The device shows a good resistance to several cycles of decontamination (autoclaving and ethanol immersion), is easy to be produced locally at low cost and helps addressing the shortage in FFP2 masks and face shields by providing adequate protection to healthcare workers against particles below 500 nm.
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