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Atmospheric methane oxidizing bacteria (atmMOB) constitute the sole biological sink for atmospheric methane. Still, the physiological basis allowing atmMOB to grow on air is not well understood. Here we assess the ability and strategies of seven methanotrophic species to grow with air as sole energy, carbon, and nitrogen source. Four species, including three outside the canonical atmMOB group USCα, enduringly oxidized atmospheric methane, carbon monoxide, and hydrogen during 12 months of growth on air. These four species exhibited distinct substrate preferences implying the existence of multiple metabolic strategies to grow on air. The estimated energy yields of the atmMOB were substantially lower than previously assumed necessary for cellular maintenance in atmMOB and other aerobic microorganisms. Moreover, the atmMOB also covered their nitrogen requirements from air. During growth on air, the atmMOB decreased investments in biosynthesis while increasing investments in trace gas oxidation. Furthermore, we confirm that a high apparent specific affinity for methane is a key characteristic of atmMOB. Our work shows that atmMOB grow on the trace concentrations of methane, carbon monoxide, and hydrogen present in air and outlines the metabolic strategies that enable atmMOB to mitigate greenhouse gases. Atmospheric methane-oxidizing bacteria constitute the sole biological sink for atmospheric methane. Here, Schmider et al. assess the ability and strategies of seven methanotrophic species to grow with air as sole energy, carbon, and nitrogen source, showing that these bacteria can grow on the trace concentrations of methane, carbon monoxide, and hydrogen present in air. [ABSTRACT FROM AUTHOR]

The Golgi apparatus is essential for protein sorting, yet its quality control mechanisms are poorly understood. Here we show that the Dsc ubiquitin ligase complex uses its rhomboid pseudo-protease subunit, Dsc2, to assess the hydrophobic length of α-helical transmembrane domains (TMDs) at the Golgi. Thereby the Dsc complex likely interacts with orphaned ER and Golgi proteins that have shorter TMDs and ubiquitinates them for targeted degradation. Some Dsc substrates will be extracted by Cdc48 for endosome and Golgi associated proteasomal degradation (EGAD), while others will undergo ESCRT dependent vacuolar degradation. Some substrates are degraded by both, EGAD- or ESCRT pathways. The accumulation of Dsc substrates entails a specific increase in glycerophospholipids with shorter and asymmetric fatty acyl chains. Hence, the Dsc complex mediates the selective degradation of orphaned proteins at the sorting center of cells, which prevents their spreading across other organelles and thereby preserves cellular membrane protein and lipid composition. At the Golgi, the Dsc ubiquitin ligase complex targets proteins with shorter transmembrane domains for proteasomal or lysosomal degradation. This quality control at the sorting center of cells restricts the uncontrolled spreading of orphaned proteins. [ABSTRACT FROM AUTHOR]

We present LinStab2D, an easy-to-use linear stability analysis MATLAB tool capable of handling complex domains, performing temporal and spatial linear stability, and resolvent analysis. We present the theoretical foundations of the code, including the linear stability and resolvent analysis frameworks, finite differences discretization schemes, and the Floquet ansatz. These concepts are explored in five different examples, highlighting and illustrating the different code capabilities, including mesh masking, mapping, imposition of boundary constraints, and the analysis of periodic flows using Cartesian or axisymmetric coordinates. These examples were constructed to be a departure point for studying other flows. [ABSTRACT FROM AUTHOR]

Sphingolipids are essential components of eukaryotic cell membranes. They typically increase the rigidity of membranes and stabilize membrane-embedded proteins. Yet, they also function as signaling molecules, and some biosynthetic intermediates are toxic at high concentrations, necessitating a tight control of cellular sphingolipid synthesis. We will discuss evolutionarily common regulatory principles, which – upon failure – can lead to devastating neurodegenerative disease in humans. [ABSTRACT FROM AUTHOR]

Different transition to turbulence routes for the flow around blunt bodies are possible. Non-modal amplification of perturbations via the lift-up effect has recently been explored to explain transition near the stagnation point in axisymmetric bodies. However, only perturbations already present in the boundary layer can be amplified, and the mechanisms by which free-stream perturbations enter the boundary layer have not yet been fully explored. In this study, we present an investigation of how disturbances enter the boundary layer via the stagnation point. This linear mechanism is expected to dominate over non-linear mechanisms previously identified on the formation of boundary layer perturbations at low turbulence intensity levels. A parametric investigation is presented, revealing trends with Reynolds and Mach numbers. [ABSTRACT FROM AUTHOR]

An adaptive algorithm for spectral proper orthogonal decomposition (SPOD) of mixed broadband-tonal turbulent flows is developed. Sharp peak resolution at tonal frequencies is achieved by locally minimizing bias of the spectrum. Smooth spectrum estimates of broadband regions are achieved by locally reducing variance of the spectrum. The method utilizes multitaper estimation with sine tapers. An iterative criterion based on modal convergence is introduced to enable the SPOD to adapt to spectral features. For tonal flows, the adaptivity is controlled by a single user input; for broadband flows, a constant number of sine tapers is recommended without adaptivity. The discrete version of Parseval's theorem for SPOD is stated. Proper normalization of the tapers ensures that Parseval's theorem is satisfied in expectation. Drastic savings in computational complexity and memory usage are facilitated by two aspects: (i) sine tapers, which permit post hoc windowing of a single Fourier transform; and (ii) time-domain lossless compression using a QR or eigenvalue decomposition. Sine-taper SPOD is demonstrated on time-resolved particle image velocimetry (TR-PIV) data from an open cavity flow (Zhang et al. in Exp Fluids 61(226):1–12, https://doi.org/10.1007/s00348-020-03057-8, 2020) and high-fidelity large-eddy simulation (LES) data from a round jet (Brès et al. in J. Fluid Mech. 851:83–124, https://doi.org/10.1017/jfm.2018.476, 2018), with and without adaptivity. For the tonal cavity flow, the adaptive algorithm outperforms Slepian-based multitaper SPOD in terms of variance and local bias of the spectrum, mode convergence, and memory usage. The tonal frequencies associated with the Rossiter instability are accurately identified. For both the tonal cavity and the broadband jet flows, results comparable to or better than those from standard SPOD based on Welch's overlapped segment averaging are obtained with up to 75% fewer snapshots, including similar convergence of the Rossiter modes and Kelvin-Helmholtz wavepacket structures for the cavity and jet examples, respectively. Drawing from these examples, we establish best practices. [ABSTRACT FROM AUTHOR]

Modification of the magnetic properties under the induced strain and curvature is a promising avenue to build three-dimensional magnetic devices, based on the domain wall motion. So far, most of the studies with 3D magnetic structures were performed in the helixes and nanowires, mainly with stationary domain walls. In this study, we demonstrate the impact of 3D geometry, strain and curvature on the current-induced domain wall motion and spin-orbital torque efficiency in the heterostructure, realized via a self-assembly rolling technique on a polymeric platform. We introduce a complete 3D memory unit with write, read and store functionality, all based on the field-free domain wall motion. Additionally, we conducted a comparative analysis between 2D and 3D structures, particularly addressing the influence of heat during the electric current pulse sequences. Finally, we demonstrated a remarkable increase of 30% in spin-torque efficiency in 3D configuration.The authors report an alternative approach to build 3D magnetic memories by rolling Co/Pt stripes on flexible polymers in compact geometry, and simultaneously offering current-induced domain wall motion and strain-induced domain wall speed control. [ABSTRACT FROM AUTHOR]

Micro-and nanorobots have the potential to perform non-invasive drug delivery, sensing, and surgery in living organisms, with the aid of diverse medical imaging techniques. To perform such actions, microrobots require high spatiotemporal resolution tracking with real-time closed-loop feedback. To that end, photoacoustic imaging has appeared as a promising technique for imaging microrobots in deep tissue with higher molecular specificity and contrast. Here, we present different strategies to track magnetically-driven micromotors with improved contrast and specificity using dedicated contrast agents (Au nanorods and nanostars). Furthermore, we discuss the possibility of improving the light absorption properties of the employed nanomaterials considering possible light scattering and coupling to the underlying metal-oxide layers on the micromotor's surface. For that, 2D COMSOL simulation and experimental results were correlated, confirming that an increased spacing between the Au-nanostructures and the increase of thickness of the underlying oxide layer lead to enhanced light absorption and preservation of the characteristic absorption peak. These characteristics are important when visualizing the micromotors in a complex in vivo environment, to distinguish them from the light absorption properties of the surrounding natural chromophores. [ABSTRACT FROM AUTHOR]

The Möbius strip, a fascinating loop structure with one-sided topology, provides a rich playground for manipulating the non-trivial topological behaviour of spinning particles, such as electrons, polaritons and photons, in both real and parameter spaces. For photons resonating in a Möbius-strip cavity, the occurrence of an extra phase—known as the Berry phase—with purely topological origin is expected due to its non-trivial evolution in parameter space. However, despite numerous theoretical investigations, characterizing the optical Berry phase in a Möbius-strip cavity has remained elusive. Here we report the experimental observation of the Berry phase generated in optical Möbius-strip microcavities. In contrast to theoretical predictions in optical, electronic and magnetic Möbius-topology systems where only Berry phase π occurs, we demonstrate that a variable Berry phase smaller than π can be acquired by generating elliptical polarization of resonating light. Möbius-strip microcavities as integrable and Berry-phase-programmable optical systems are of great interest in topological physics and emerging classical or quantum photonic applications. The existence of the optical Berry phase in all-dielectric Möbius-strip cavities is experimentally confirmed. In contrast to a predicted sole Berry phase value of π, arbitrary values of the Berry phase upon adiabatic evolution of a linearly or elliptically polarized light wave are obtained. [ABSTRACT FROM AUTHOR]

The use of multitaper estimates for spectral proper orthogonal decomposition (SPOD) is explored. Multitaper and multitaper-Welch estimators that use discrete prolate spheroidal sequences (DPSS) as orthogonal data windows are compared to the standard SPOD algorithm that exclusively relies on weighted overlapped segment averaging, or Welch's method, to estimate the cross-spectral density matrix. Two sets of turbulent flow data, one experimental and the other numerical, are used to discuss the choice of resolution bandwidth and the bias-variance tradeoff. Multitaper-Welch estimators that combine both approaches by applying orthogonal tapers to overlapping segments allow for flexible control of resolution, variance, and bias. At additional computational cost but for the same data, multitaper-Welch estimators provide lower variance estimates at fixed frequency resolution or higher frequency resolution at similar variance compared to the standard algorithm. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Self-assembly of Co/Pt stripes with current-induced domain wall motion towards 3D racetrack devices" published in Nature Communications. The correction addresses errors in two figures, Fig. 1a and Fig. 3f, where labels were misaligned and not readable, respectively. The correct versions of the figures have been provided in both the PDF and HTML versions of the article. The authors of the article are Pavel Fedorov, Ivan Soldatov, Volker Neu, Rudolf Schäfer, Oliver G. Schmidt, and Daniil Karnaushenko. [Extracted from the article]

The extension of 2D ferromagnetic structures into 3D curved geometry enables to tune its magnetic properties such as uniaxial magnetic anisotropy. Tuning the anisotropy with strain and curvature has become a promising ingredient in modern electronics, such as flexible and stretchable magnetoelectronic devices, impedance-based field sensors, and strain gauges, however, has been limited to extended thin films and to only moderate bending. By applying a self-assembly rolling technique using a polymeric platform, we provide a template that allows homogeneous and controlled bending of a functional layer adhered to it, irrespective of its shape and size. This is an intriguing possibility to tailor the sign and magnitude of the surface strain of integrated, micron-sized devices. In this article, the impact of strain and curvature on the magnetic ground state and anisotropy is quantified for thin-film Permalloy micro-scale structures, fabricated on the surface of the tubular architectures, using solely electrical measurements. [ABSTRACT FROM AUTHOR]

Molecular devices constructed by sub-10 nm thick molecular layers are promising candidates for a new generation of integratable nanoelectronic applications. Here, we report integrated molecular devices based on ultrathin copper phthalocyanine/fullerene hybrid layers with microtubular soft-contacts, which exhibit process-programmable functionality switching between photomultiplication and memristive behaviour. The local electric field at the interface between the polymer bottom electrode and the enclosed molecular channels modulates the ionic-electronic charge interaction and hence determines the transition of the device function. When ions are not driven into the molecular channels at a low interface electric field, photogenerated holes are trapped as electronic space charges, resulting in photomultiplication with a high external quantum efficiency. Once mobile ions are polarized and accumulated as ionic space charges in the molecular channels at a high interface electric field, the molecular devices show ferroelectric-like memristive switching with remarkable resistive ON/OFF and rectification ratios. Developing molecular electronics is challenged by integrating fragile organic molecules into modern micro/nanoelectronics based on inorganic semiconductors. Li et al. apply rolled-up nanotechnology to assemble on-chip molecular devices, which can be switched between photodiodes and volatile memristors. [ABSTRACT FROM AUTHOR]

Magnetic sensors are widely used in our daily life for assessing the position and orientation of objects. Recently, the magnetic sensing modality has been introduced to electronic skins (e-skins), enabling remote perception of moving objects. However, the integration density of magnetic sensors is limited and the vector properties of the magnetic field cannot be fully explored since the sensors can only perceive field components in one or two dimensions. Here, we report an approach to fabricate high-density integrated active matrix magnetic sensor with three-dimensional (3D) magnetic vector field sensing capability. The 3D magnetic sensor is composed of an array of self-assembled micro-origami cubic architectures with biased anisotropic magnetoresistance (AMR) sensors manufactured in a wafer-scale process. Integrating the 3D magnetic sensors into an e-skin with embedded magnetic hairs enables real-time multidirectional tactile perception. We demonstrate a versatile approach for the fabrication of active matrix integrated 3D sensor arrays using micro-origami and pave the way for new electronic devices relying on the autonomous rearrangement of functional elements in space. State-of-the-art magnetic skins can only sense in one or two-dimensions, at small spatial resolutions. By combining the ancient art of paper folding, origami, with advanced semiconductor technology, here, authors present cutting edge three-dimensional magnetic sensors. [ABSTRACT FROM AUTHOR]

The use of spectral proper orthogonal decomposition (SPOD) to construct low-order models for broadband turbulent flows is explored. The choice of SPOD modes as basis vectors is motivated by their optimality and space-time coherence properties for statistically stationary flows. This work follows the modeling paradigm that complex nonlinear fluid dynamics can be approximated as stochastically forced linear systems. The proposed stochastic two-level SPOD-Galerkin model governs a compound state consisting of the modal expansion coefficients and forcing coefficients. In the first level, the modal expansion coefficients are advanced by the forced linearized Navier-Stokes operator under the linear time-invariant assumption. The second level governs the forcing coefficients, which compensate for the offset between the linear approximation and the true state. At this level, least squares regression is used to achieve closure by modeling nonlinear interactions between modes. The statistics of the remaining residue are used to construct a dewhitening filter that facilitates the use of white noise to drive the model. If the data residue is used as the sole input, the model accurately recovers the original flow trajectory for all times. If the residue is modeled as stochastic input, then the model generates surrogate data that accurately reproduces the second-order statistics and dynamics of the original data. The stochastic model uncertainty, predictability, and stability are quantified analytically and through Monte Carlo simulations. The model is demonstrated on large eddy simulation data of a turbulent jet at Mach number M = 0.9 and Reynolds number Re D ≈ 10 6 . [ABSTRACT FROM AUTHOR]

Today's smallest energy storage devices for in-vivo applications are larger than 3 mm3 and lack the ability to continuously drive the complex functions of smart dust electronic and microrobotic systems. Here, we create a tubular biosupercapacitor occupying a mere volume of 1/1000 mm3 (=1 nanoliter), yet delivering up to 1.6 V in blood. The tubular geometry of this nano-biosupercapacitor provides efficient self-protection against external forces from pulsating blood or muscle contraction. Redox enzymes and living cells, naturally present in blood boost the performance of the device by 40% and help to solve the self-discharging problem persistently encountered by miniaturized supercapacitors. At full capacity, the nano-biosupercapacitors drive a complex integrated sensor system to measure the pH-value in blood. This demonstration opens up opportunities for next generation intravascular implants and microrobotic systems operating in hard-to-reach small spaces deep inside the human body. The miniaturization of biocompatible microsystems that enable self-sufficiency and autarkic operations is ever increasing. Here, the authors demonstrate a robust integratable nano-biosupercapacitor with enhanced performance in complex biological fluids, thus enabling autarkic sensor operation in blood. [ABSTRACT FROM AUTHOR]

Highlights: A zero-reflection-induced phase singularity is achieved through precisely controlling the resonance characteristics using two-dimensional nanomaterials. An atomically thin nano-layer having a high absorption coefficient is exploited to enhance the zero-reflection dip, which has led to the subsequent phase singularity and thus a giant lateral position shift. We have improved the detection limit of low molecular weight molecules by more than three orders of magnitude compared to current state-of-art nanomaterial-enhanced plasmonic sensors. Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer, monitoring treatment and detecting relapse. Here, a highly enhanced plasmonic biosensor that can overcome this challenge is developed using atomically thin two-dimensional phase change nanomaterial. By precisely engineering the configuration with atomically thin materials, the phase singularity has been successfully achieved with a significantly enhanced lateral position shift effect. Based on our knowledge, it is the first experimental demonstration of a lateral position signal change > 340 μm at a sensing interface from all optical techniques. With this enhanced plasmonic effect, the detection limit has been experimentally demonstrated to be 10–15 mol L−1 for TNF-α cancer marker, which has been found in various human diseases including inflammatory diseases and different kinds of cancer. The as-reported novel integration of atomically thin Ge2Sb2Te5 with plasmonic substrate, which results in a phase singularity and thus a giant lateral position shift, enables the detection of cancer markers with low molecular weight at femtomolar level. These results will definitely hold promising potential in biomedical application and clinical diagnostics. [ABSTRACT FROM AUTHOR]

Triadic interactions are the fundamental mechanism of energy transfer in fluid flows. This work introduces bispectral mode decomposition as a direct means of educing flow structures that are associated with triadic interactions from experimental or numerical data. Triadic interactions are characterized by quadratic phase coupling which can be detected by the bispectrum. The proposed method maximizes an integral measure of this third-order statistic to compute modes associated with frequency triads, as well as a mode bispectrum that identifies resonant three-wave interactions. Unlike the classical bispectrum, the decomposition establishes a causal relationship between the three frequency components of a triad. This permits the distinction of sum- and difference-interactions, and the computation of interaction maps that indicate regions of nonlinear coupling. Three examples highlight different aspects of the method. Cascading triads and their regions of interaction are educed from direct numerical simulation data of laminar cylinder flow. It is further demonstrated that linear instability mechanisms that attain an appreciable amplitude are revealed indirectly by their difference-self-interactions. Applicability to turbulent flows and noise-rejection is demonstrated on particle image velocimetry data of a massively separated wake. The generation of sub- and ultra-harmonics in large eddy simulation data of a transitional jet is explained by extending the method to cross-bispectral information. [ABSTRACT FROM AUTHOR]

Considerable efforts have been made to realize nanoscale diodes based on single molecules or molecular ensembles for implementing the concept of molecular electronics. However, so far, functional molecular diodes have only been demonstrated in the very low alternating current frequency regime, which is partially due to their extremely low conductance and the poor degree of device integration. Here, we report about fully integrated rectifiers with microtubular soft-contacts, which are based on a molecularly thin organic heterojunction and are able to convert alternating current with a frequency of up to 10 MHz. The unidirectional current behavior of our devices originates mainly from the intrinsically different surfaces of the bottom planar and top microtubular Au electrodes while the excellent high frequency response benefits from the charge accumulation in the phthalocyanine molecular heterojunction, which not only improves the charge injection but also increases the carrier density. The demand for miniaturization of electronics has been motivating a growing interest in high-performance molecular electronics. Li, Bandari et al. report a fully integrated molecular rectifier based on a molecular heterojunction and microtubular electrode enabling high frequency operation at more than 10 MHz. [ABSTRACT FROM AUTHOR]

A novel small signal equivalent circuit model is proposed in the inversion regime of metal/(ZnO, ZnMnO, and ZnCoO) semiconductor/Si3N4 insulator/p-Si semiconductor (MSIS) structures to describe the distinctive nonlinear frequency dependent capacitance (C-F) and conductance (G-F) behaviour in the frequency range from 50 Hz to 1 MHz. We modelled the fully depleted ZnO thin films to extract the static dielectric constant (εr) of ZnO, ZnMnO, and ZnCoO. The extracted enhancement of static dielectric constant in magnetic n-type conducting ZnCoO (εr ≥ 13.0) and ZnMnO (εr ≥ 25.8) in comparison to unmagnetic ZnO (εr = 8.3–9.3) is related to the electrical polarizability of donor-type bound magnetic polarons (BMP) in the several hundred GHz range (120 GHz for CdMnTe). The formation of donor-BMP is enabled in n-type conducting, magnetic ZnO by the s-d exchange interaction between the electron spin of positively charged oxygen vacancies V o + in the BMP center and the electron spins of substitutional Mn2+ and Co2+ ions in ZnMnO and ZnCoO, respectively. The BMP radius scales with the Bohr radius which is proportional to the static dielectric constant. Here we show how BMP overlap can be realized in magnetic n-ZnO by increasing its static dielectric constant and guide researchers in the field of transparent spintronics towards ferromagnetism in magnetic, n-ZnO. [ABSTRACT FROM AUTHOR]

Improve materials and architectures to shrink microscopic devices. [ABSTRACT FROM AUTHOR]

Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI3) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI3 wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 µC Gyair−1 cm−2 under 70 kVp X-ray exposure. The high ambipolar mobility-lifetime product of 2 × 10−4 cm2 V−1 is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafers. [ABSTRACT FROM AUTHOR]

Graphene oxide shows great promise as a material for biomedical applications, e.g., as a multi-drug delivery platform. With this in view, reports of studies on the interaction between nanosized graphene oxide flakes and biological cells are beginning to emerge. However, the number of studies remains limited, and most used labeled graphene oxide samples to track the material upon endocytosis. Unfortunately, the labeling process alters the surface functionality of the graphene oxide, and this additional functionalization has been shown to alter the cellular response. Hence, in this work we used label-free graphene oxide. We carefully tracked the uptake of three different nanoscale graphene oxide flake size distributions using scanning/transmission electron microscopy. Uptake was investigated in undifferentiated human monocyte cells (THP-1) and differentiated macrophage cells. The data show clear size dependence for uptake, such that larger graphene oxide flakes (and clusters) are more easily taken up by the cells compared to smaller flakes. Moreover, uptake is shown to occur very rapidly, within two min of incubation with THP-1 cells. The data highlights a crucial need for cellular incubation studies with nanoparticles, to be conducted for short incubation periods as certain dependencies (e.g., size and concentration) are lost with longer incubation periods. [ABSTRACT FROM AUTHOR]

The resistive switching of epitaxial ferroelectric BiFeO thin films was investigated by the combined current and capacitance spectroscopy, in addition with the piezoresponse force microscopy and conducting atomic force microscopy. A strong correlation between the resistance states and the capacitance states was found in the temperature range from 77 to 300 K, revealing the role of interface traps. It is demonstrated that the trap-assisted current transport contributes to the large ON current of the ferroelectric and flexible barrier resistive switching. The combination of ferroelectric polarization reversal, electromigration of oxygen vacancies, and interface traps leads to the nonvolatile memory performance with the ON/OFF ratio of 10 for >10 s and the endurance of over 8000 cycles at room temperature. [ABSTRACT FROM AUTHOR]

In a manner reminiscent of macroscale bending and folding techniques such as origami, the out-of-plane assembly of lithographically micro- and nanopatterned thin films, can be used to fabricate three-dimensional (3D) micro- and nanostructured devices. These 3D devices, including microelectronic circuits, sensors, antennas, metamaterials, robotic, and biomimetic constructs, enable new functionalities and are challenging to fabricate by other methods. In this article, we summarize important features of this set of techniques and the devices assembled thereof, with a focus on functional constructs that have been formed by bending, folding, or buckling. At small size scales, manipulation using manual or even wired probes face daunting practical challenges in terms of cost, scalability, and high-throughput manufacturability; hence we emphasize techniques that manipulate strain in thin films so that they can spontaneously assemble into programmed 3D geometries without the need for any wires or probes. [ABSTRACT FROM PUBLISHER]

Self-propelled microrobots have recently shown promising results in several scenarios at the microscale, such as targeted drug delivery and micromanipulation of cells. However, none of the steering systems available in the literature enable humans to intuitively and effectively control these microrobots in the remote environment, which is a desirable feature. In this paper we present an innovative teleoperation system with force reflection that enables a human operator to intuitively control the positioning of a self-propelled microjet. A particle-filter-based visual tracking algorithm tracks at runtime the position of the microjet in the remote environment. A 6-degrees-of-freedom haptic interface then provides the human operator with compelling haptic feedback about the interaction between the controlled microjet and the environment, as well as enabling the operator to intuitively control the target position of the microjet. Finally, a wireless magnetic control system regulates the orientation of the microjet to reach the target point. The viability of the proposed approach is demonstrated through two experimentsz enrolling twenty-eight subjects. In both experiments providing haptic feedback significantly improved the performance and the perceived realism of the considered tasks. [ABSTRACT FROM AUTHOR]

We apply the technique of supervised discriminant analysis (SDA) for in-flow detection in droplet-based magnetofluidics. Based on the SDA, we successfully discriminate bivariant droplets of different volumes containing different encapsulated magnetic content produced by a GMR-based lab-on-chip platform. We demonstrate that the accuracy of discrimination is superior when the correlation of variables for data training is included to the case when the spatial distribution of variables is considered. Droplets produced with differences in ferrofluid concentration of 2.5 mg/ml and volume of 200 pl have been identified with high accuracy (98 %), indicating the significance of SDA for e.g. the discrimination in magnetic immuno-agglutination assays. Furthermore, the results open the way for the development of a unique magnetofluidic platform for future applications in multiplexed droplet-based barcoding assays and screening. [ABSTRACT FROM AUTHOR]

The concept of Fourier synthesis is heavily used in both consumer electronic products and fundamental research. In the latter, pulse shaping is key to dynamically initializing, probing and manipulating the state of classical or quantum systems. In NMR, for instance, shaped pulses have a long-standing tradition and the underlying fundamental concepts have subsequently been successfully extended to optical frequencies and even to the implementation of quantum gate operations. Transferring these paradigms to nanomechanical systems requires tailored nanomechanical waveforms. Here, we report on an additive Fourier synthesizer for nanomechanical waveforms based on monochromatic surface acoustic waves. As a proof of concept, we electrically synthesize four different elementary nanomechanical waveforms from a fundamental surface acoustic wave at f1 ≈ 150 MHz using a superposition of up to three discrete harmonics. We use these shaped pulses to interact with an individual sensor quantum dot and detect their deliberately and temporally modulated strain component via the optomechanical quantum dot response. Importantly, and in contrast to direct mechanical actuation by bulk piezoactuators, surface acoustic waves provide much higher frequencies (>20 GHz; ref. 10) to resonantly drive mechanical motion. Thus, our technique uniquely allows coherent mechanical control of localized vibronic modes of optomechanical crystals, even in the quantum limit when cooled to the vibrational ground state. [ABSTRACT FROM AUTHOR]

White wine spoilage due to oxidation is a major concern during post-fermentation treatments and bottling. In this study, we explored the effects of different oxygen and free SO levels and ascorbic acid addition on the development of white wine. Riesling wine was bottled in 500-mL bottles under screw caps with four different headspace volumes (0, 10, 20 and 30 mL), two levels of free SO (45 and 70 mg/L) and with and without ascorbic acid (250 mg/L) addition giving 16 wines for analysis. Cold stored (at 5 °C) control was used as reference for data analysis and sensory evaluation. Dissolved oxygen and the oxygen in headspace were measured in the resulting 17 wines. Free and total SO concentrations, ascorbic acid concentration, colour, redox potential and antioxidative capacity were measured regularly in wine samples. After 6 months of storage, the wines were evaluated using descriptive sensory analysis. Both sensory and analytical results showed significant differences among the wines. Intensive wine exposure to oxygen (headspace volume) affected colour, free and total SO rate, and the overall sensory quality of wine. Ascorbic acid addition had positive effect on the sensory evaluation of wines and on SO levels, whereas combined with large headspace volumes, provoked intensive browning in wine samples. [ABSTRACT FROM AUTHOR]

Titania nanotube arrays have been prepared by anodic oxidation of titanium foils in an electrolyte solution containing a mixture of hydrofluoric acid, ethylene glycol, and phosphoric acid. The initially amorphous nanotubes were found to crystalize in an anatase phase upon thermal treatment at 500°C. Anatase crystalline phase showed a significant improvement in the photocatalytic properties of the prepared samples, which was evaluated by studying their efficiency towards Rhodamine B dye degradation. Additionally, the effect of doping titania nanotubes with noble metals (e.g. Ag, Pt, and Au), or covering their surface with noble metal nanoparticles, was studied regarding their capabilities towards the photocatalytic degradation of Rhodamine B dye. A positive effect when samples were doped with Ag was revealed. [ABSTRACT FROM AUTHOR]

With Fe2O3 as a proof-of-concept, free-standing nanomembrane structure is demonstrated to be highly advantageous to improve the performance of Li-ion batteries. The Fe2O3 nanomembrane electrodes exhibit ultra-long cycling life at high current rates with satisfactory capacity (808 mAh g1 after 1000 cycles at 2 C and 530 mAh g1 after 3000 cycles at 6 C) as well as repeatable high rate capability up to 50 C. The excellent performance benefits particularly from the unique structural advantages of the nanomembranes. The mechanical feature can buffer the strain of lithiation/delithiation to postpone the pulverization. The two-dimensional transport pathways in between the nanomembranes can promote the pseudo-capacitive type storage. The parallel-laid nanomembranes, which are coated by polymeric gel-like film and SEI layer with the electrolyte in between layers, electrochemically behave like numerous "mini-capacitors" to provide the pseudo-capacitance thus maintain the capacity at high rate. [ABSTRACT FROM AUTHOR]