Direct-written polymer field-effect transistors operating at 20 MHz

Printed polymer electronics has held for long the promise of revolutionizing technology by delivering distributed, flexible, lightweight and cost-effective applications for wearables, healthcare, diagnostic, automation and portable devices. While impressive progresses have been registered in terms of organic semiconductors mobility, field-effect transistors (FETs), the basic building block of any circuit, are still showing limited speed of operation, thus limiting their real applicability. So far, attempts with organic FETs to achieve the tens of MHz regime, a threshold for many applications comprising the driving of high resolution displays, have relied on the adoption of sophisticated lithographic techniques and/or complex architectures, undermining the whole concept. In this work we demonstrate polymer FETs which can operate up to 20 MHz and are fabricated by means only of scalable printing techniques and direct-writing methods with a completely mask-less procedure. This is achieved by combining a fs-laser process for the sintering of high resolution metal electrodes, thus easily achieving micron-scale channels with reduced parasitism down to 0.19 pF mm(-1), and a large area coating technique of a high mobility polymer semiconductor, according to a simple and scalable process flow

In vivo assessment of CdSe-ZnS quantum dots: coating dependent bioaccumulation and genotoxicity.

Semiconductor nanocrystals, or Quantum Dots (QDs), have gained considerable attention due to their unique size-dependent optical and electronic properties that make them attractive for a wide range of applications, including biology and nanomedicine. Their widespread use, however, poses urgent questions about their potential toxicity, especially because of their heavy metal composition that could cause harmful effects to human health and environment. In this work, we evaluated in vivo the long-term toxicity of CdSe-ZnS QDs with different surface coatings, probing oral administration in the model system Drosophila melanogaster. In particular, we found that all the differently coated QDs significantly affect the lifespan of treated Drosophila populations and induce a marked increase in reactive oxygen species (ROS) levels. Furthermore, we observed that these QDs induce severe genotoxic effects and increased rate of apoptosis in Drosophila haemocytes. These toxic effects were found to be mainly related to the in vivo degradation of QDs with consequent release of Cd(2+) ions, while the coating of QDs can modulate their bioaccumulation in the organism, partly decreasing their overall toxicity

Negligible particle-specific toxicity mechanism of silver nanoparticles: The role of Ag+ion release in the cytosol

Toxicity of silver nanoparticles (AgNPs) is supported by many observations in literature, but no mechanism details have been proved yet. Here we confirm and quantify the toxic potential of fully characterized AgNPs in HeLa and A549 cells. Notably, through a specific fluorescent probe, we demonstrate the intracellular release of Ag+ ions in living cells after nanoparticle internalization, showing that in-situ particle degradation is promoted by the acidic lysosomal environment. The activation of metallothioneins in response to AgNPs and the possibility to reverse the main toxic pathway by Ag+ chelating agents demonstrate a cause/effect relationship between ions and cell death. We propose that endocytosed AgNPs are degraded in the lysosomes and the release of Ag+ ions in the cytosol induces cell damages, while ions released in the cell culture medium play a negligible effect. These findings will be useful to develop safer-by-design nanoparticles and proper regulatory guidelines of AgNPs

The borderland of migraine with aura: episodic unilateral mydriasis

We present the case of a patient who had a 3-year history of episodes of transitory unilateral mydriasis with omolateral blurred vision followed by headache. Thereafter, during the last 4 years, the patient developed a migraine with visual aura, without further episodes of transitory mydriasis. We suggest that the transitory mydriasis previously present could be considered as an unusual form of migrainous aura. A possible pathogenetic mechanism is proposed

Characterization of an innovative like-eye sensor for feature detection and robot sensing

In this paper the authors present an application of an innovative device consisting in a new optical sensor accurately moved by driving a controlled robotic arm. The new sensor is made up of nanocomposite material and it is composed of an optical fiber source, an optical fiber bundle receiver and a PDMS-Au tip able to enhance the light. The device allows to reconstruct the target characteristics taking advantage of the backscattered light. The motion of the sensor is obtained by means of a robot manipulator which gripper grasps and moves the sensor. The realized device has been tested in order to evaluate its ability to provide useful information on colours, surface opacity and profile of the detected objects