Synthetic Devices Research Articles

Voltage control of magnetic order in RKKY coupled multilayers.

In the field of antiferromagnetic (AFM) spintronics, there is a substantial effort present to make AFMs viable active components for efficient and fast devices. Typically, this is done by manipulating the AFM Néel vector. Here, we establish a method of enabling AFM active components by directly controlling the magnetic order. We show that magneto-ionic gating of hydrogen enables dynamic control of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in solid-state synthetic AFM multilayer devices. Using a gate voltage, we tune the RKKY interaction to drive continuous transitions from AFM to FM and vice versa. The switching is submillisecond at room temperature and fully reversible. We validate the utility of this method by demonstrating that magneto-ionic gating of the RKKY interaction allows for 180° field-free deterministic switching. This dynamic method of controlling a fundamental exchange interaction can engender the manipulation of a broader array of spin textures, e.g., chiral domain walls and skyrmions.

The male slings: an effective and safe alternative surgical treatment to the artificial urinary sphincter for male stress urinary incontinence?-a narrative review.

The ideal candidate for a male sling (MS) should have a mild to moderate degree of stress urinary incontinence (SUI). This narrative review article evaluates the current MS devices in the commercial market and examines the role of MS as an effective and safe alternative treatment option for male SUI. The available literature on MS was reviewed and relevant clinical studies pertaining to each MS were summarised with emphasis on device design and technology as well as specific surgical findings relating to clinical outcomes. Over the past two decades, there have been considerable scientific advances in MS design and technology, and MS is an attractive alternative for patients who might not require or want an artificial urinary sphincter. The modern MS can be classified as adjustable or non-adjustable types and is placed either through a retropubic or transobturator (TO) approach. Strict patient selection and counselling, selection of MS with proven clinical records, and safe surgical practice are paramount to ensure a high continence rate, good patient satisfaction, and low postoperative complications. Published data on various MS materials and devices showed reasonable clinical efficacy and safety outcomes, although many of these synthetic MS devices may not be available worldwide due to a lack of regulatory approval in many countries. While the ideal MS is probably yet to be developed, continued scientific advances in slings design, mesh technology, and more refined surgical techniques will improve the continence rate and deliver better safety records. As clinical data matures with longer-term outcomes coupled with advances in scientific designs and technology, the ability to have and select the optimal MS for a particular patient will come to fruition.

The research on the influence of temperature on the properties of synthetic fibres for load-handling devices

This article presents the results of experimental studies aimed at analyzing the impact of various temperature conditions on the performance characteristics of synthetic fibres and threads, widely used in lifting devices in construction. Not only the positive aspects of using these materials are discussed, but also the design features of synthetic load-bearing devices. In addition, a classification of materials used in the lifting industry is carried out, with an emphasis on polymer complex fibres. The physicomechanical and physicochemical properties of these materials are studied at various temperature conditions. To achieve these goals, research was carried out using modern physical-mechanical, physical-chemical, mathematical-statistical methods, methods of mathematical modelling, experimental planning, as well as methods of computer science and computational mathematics. These methods ensured the reliability and accuracy of the results obtained, which allows us to draw conclusions that have practical significance for the design and operation of lifting systems in a variety of climatic conditions.

Sputter Gas Damage in Nanolayered Pt/Co/Ir-based Synthetic Antiferromagnets for Top-Pinned Magnetic Tunnel Junctions

We examine the role of sputter damage on limiting the perpendicular magnetic anisotropy and interlayer exchange coupling in Pt/Co/Ir-based synthetic antiferromagnets, a key building block used in the microelectronics community for standalone and embedded magnetic random access memories. By replacing the more conventional Ar process gas with Kr or Xe, we reduce the energy of backscattered sputter gas ions bombarding the substrate from in excess of 100 eV to a few 10 s of eV. Reducing this kinetic bombardment is critical to avoid intermixing of this nanolayered functional heterostructure, with the constituent Pt, Co, and Ir layer thicknesses each below 1 nm. Our approach leads to a simultaneous enhancement in the perpendicular magnetic anisotropy (>2 × 106 J/m3) and interlayer exchange coupling energy (>3.5 mJ/m2). This advantageous improvement in perpendicular anisotropy and interlayer exchange coupling is evident on a 5 nm-thick Pt buffer layer and additionally on an MgO/CoFeB/Mo underlayers complex, showing that this method can improve the performance of both top- and bottom-pinned reference layers in perpendicular magnetic tunnel junction devices. These experimental findings may help advance the processing of conventional and synthetic antiferromagnetic devices for emerging spintronic memory technologies.

Optical Tweezers to Force Information out of Biological and Synthetic Systems One Molecule at a Time

Over the last few decades, in vitro single-molecule manipulation techniques have enabled the use of force and displacement as controlled variables in biochemistry. Measuring the effect of mechanical force on the real-time kinetics of a biological process gives us access to the rates, equilibrium constants and free-energy landscapes of the mechanical steps of the reaction; this information is not accessible by ensemble assays. Optical tweezers are the current method of choice in single-molecule manipulation due to their versatility, high force and spatial and temporal resolutions. The aim of this review is to describe the contributions of our lab in the single-molecule manipulation field. We present here several optical tweezers assays refined in our laboratory to probe the dynamics and mechano-chemical properties of biological molecular motors and synthetic molecular devices at the single-molecule level.

Enhanced Adhesion of Synthetic Discs with Micro-Patterned Margins.

Many aquatic creatures in nature have non-cooperative surface scaling abilities using suction organs; micro-/nano-scale structures found in different parts of the organs play an important role in this mechanism. Synthetic bioinspired suction devices have been developed, but the mechanisms of bioinspired suction system need further investigation. This paper presents the development of a synthetic adhesive disc inspired by the hillstream loach. The microscopic structures involved in adhesion of the hillstream loach were investigated. Bioinspired suction discs were designed with single-level or hierarchical micropatterned margins. Micro three-dimensional (3D) printing and micro electromechanical system (MEMs) technology were utilized in the fabrication of the discs, and the adhesion performance was tested on substrates with different roughness values. The engaging and disengaging processes of the margin were simulated by carrying out a peeling test on a submerged substrate. The interactions between the liquid film and the microstructures were observed using fluorescence microscopy. The enhanced adhesion forces due to the synergy of the hierarchically micro-patterned margin and the disc cavity were duplicated in the synthetic adhesion system.

Efficient autonomous navigation for terrestrial insect-machine hybrid systems

While bio-inspired and biomimetic systems draw inspiration from living materials, biohybrid systems incorporate them with synthetic devices, allowing the exploitation of both organic and artificial advantages inside a single entity. In the challenging development of centimeter-scaled mobile robots serving unstructured territory navigations, biohybrid systems appear as a potential solution in the forms of terrestrial insect-machine hybrid systems, which are the fusion of living ambulatory insects and miniature electronic devices. Although their maneuver can be deliberately controlled via artificial electrical stimulation, these hybrid systems still inherit the insects’ outstanding locomotory skills, orchestrated by a sophisticated central nervous system and various sensory organs, favoring their maneuvers in complex terrains. However, efficient autonomous navigation of these hybrid systems is challenging. The struggle to optimize the stimulation parameters for individual insects limits the reliability and accuracy of navigation control. This study overcomes this problem by implementing a feedback control system with an insight into tunable navigation control for an insect-machine hybrid system based on a living darkling beetle. Via a thrust controller for acceleration and a proportional controller for turning, the system regulates the stimulation parameters based on the instantaneous status of the hybrid robot. While the system can provide an overall success rate of ∼ 71% for path-following navigations, fine tuning its control parameters could further improve the outcome’s reliability and precision to up to ∼ 94% success rate and ∼ 1/2 body length accuracy, respectively. Such tunable performance of the feedback control system provides flexibility to navigation applications of insect-machine hybrid systems.

Local and global energy barriers for chiral domain walls in synthetic antiferromagnet–ferromagnet lateral junctions

Of great promise are synthetic antiferromagnet-based racetrack devices in which chiral composite domain walls can be efficiently moved by current. However, overcoming the trade-off between energy efficiency and thermal stability remains a major challenge. Here we show that chiral domain walls in a synthetic antiferromagnet–ferromagnet lateral junction are highly stable against large magnetic fields, while the domain walls can be efficiently moved across the junction by current. Our approach takes advantage of field-induced global energy barriers in the unique energy landscape of the junction that are added to the local energy barrier. We demonstrate that thermal fluctuations are equivalent to the magnetic field effect, thereby, surprisingly, increasing the energy barrier and further stabilizing the domain wall in the junction at higher temperatures, which is in sharp contrast to ferromagnets or synthetic antiferromagnets. We find that the threshold current density can be further decreased by tilting the junction without affecting the high domain wall stability. Furthermore, we demonstrate that chiral domain walls can be robustly confined within a ferromagnet region sandwiched on both sides by synthetic antiferromagnets and yet can be readily injected into the synthetic antiferromagnet regions by current. Our findings break the aforementioned trade-off, thereby allowing for versatile domain-wall-based memory, and logic, and beyond.

Метод адаптації самоспрямованого навчання майбутніх авіадиспетчерів до їх стильових особливостей для автоматизованої системи адаптивної передтренажерної підготовки

The subject matter of the article is the characteristics of learning styles of future air traffic controllers' practical learning at the basic training stage for the appropriate individual learning style formation. Besides, this study focuses on the adaptation processes of the future air traffic controllers' professional learning activities based on self-directed learning, conducted with the use of synthetic training devices in a pre-simulator training form, to the style preferences of students. The goal of the study is a method for adapting the future air traffic controllers' self-directed learning to the style characteristics of students during their pre-simulator training based on the proposed two-generic complex model of learning styles. The tasks: to explore some modern approaches to adaptive learning, taking into account the student’ style characteristics using computer-based learning systems and analyze the main models of learning styles; to develop a comprehensive model of learning styles for the future air traffic controllers' adaptive pre-simulator training and identify the key features characteristic of each style component in the context of future air traffic controllers' practical self-directed learning to make recommendations to avoid choosing inappropriate variants to implement individual learning strategies at the level of particular learning activities according to their inherent parameters of learning styles; to develop a general optimization model of adaptive learning to provide guarantees of the target practical skills level achievement by the future air traffic controller during a certain training cycle by adapting the content of the relevant individual learning strategies (selection of learning actions) to the students' style characteristics; to develop a conceptual model for adapting the future air traffic controllers' self-directed learning to their individual learning styles. The methods used are analysis, set and graph theory, optimization theory and mathematical modeling The following results were obtained. The presented conceptual model of adapting the future air traffic controllers' training activities to their style preferences based on self-directed learning can be applied in adaptive pre-simulator training, while providing the basis for determining the students' style characteristics to apply them at the stage of air traffic controller training in the "self-directed learning" mode". Conclusions. The scientific novelty of the results obtained is as follows: for the first time, a model of future air traffic controllers' individual learning styles was developed, unlike the existing ones it considers the specifics of air traffic controllers' pre-simulator and simulator training and covers the students' individual typological characteristics in a wide range: from cognitive to reflective style dimensions. The presented complex two-generic model of learning styles systematically combines two levels of adaptation of learning activities to the students' style preferences – the level of development of professional competencies and the level of development of self-directed learning skills.

Thermalization dynamics of a gauge theory on a quantum simulator.

Gauge theories form the foundation of modern physics, with applications ranging from elementary particle physics and early-universe cosmology to condensed matter systems. We perform quantum simulations of the unitary dynamics of a U(1) symmetric gauge field theory and demonstrate emergent irreversible behavior. The highly constrained gauge theory dynamics are encoded in a one-dimensional Bose-Hubbard simulator, which couples fermionic matter fields through dynamical gauge fields. We investigated global quantum quenches and the equilibration to a steady state well approximated by a thermal ensemble. Our work may enable the investigation of elusive phenomena, such as Schwinger pair production and string breaking, and paves the way for simulating more complex, higher-dimensional gauge theories on quantum synthetic matter devices.

Defect density of states in natural and synthetic MoS2 multilayer flakes

It has become important to identify and study dominant defects in different forms of transition metal dichalcogenide materials, which are being explored for use in electronic devices. We have investigated the density and distribution of deep defect states in natural and synthetic multilayer MoS2 (m–MoS2) flakes using temperature-dependent admittance spectroscopy. The flakes sandwiched between suitable electrodes with an Au|m-MoS2|ZnO structure act as good quality diodes suitable for capacitance-based studies. The defect density of states (DOS) show Gaussian distribution, and density was found to be approximately 1014 and 1013 cm−3 eV−1 in the natural and synthetic MoS2 flake devices, respectively. Both types of flakes showed a deep level around 0.8 eV below the conduction band edge with a Gaussian disorder parameter of around 33 and 30 meV, respectively, at room temperature, indicating a common origin corresponding to these defect states. The synthetic MoS2 flake device shows the appearance of an additional defect state at around 0.7 eV, which is probably related to a stoichiometric defect. Our results point to the possible occurrence of a large lattice relaxation of donors with associated trap levels deep within the gap. Our results demonstrate an excellent non-destructive method of deriving defect DOS in multilayer flakes.

Experimental and Numerical Investigations of Modified Synthetic Jet Actuator for Active Flow Control

This paper presents the results of experimental and numerical investigations on synthetic jet actuators with various arrangements. First, an actuator with one membrane in the cavity is a standard, reference arrangement; and second, one novel modified arrangement has two membranes in the cavity. Authors use constant temperature-anemometry measurements to identify the characteristic frequencies in which the output jet velocity reaches a maximal value, namely, the resonant frequency of the actuator (Helmholtz frequency) and of the membrane (structural resonance). A numerical model of a synthetic jet actuator has been validated using experimental data for the case with one membrane in a cavity. The simulation results confirm the existence of a toroidal vortex at the actuator exit for the frequencies determined in the experiment. Numerical results of a modified actuator with two membranes in the cavity give promising results in the context of separation control by synthetic jet devices, i.e., increase of output velocity and vorticity from the same occupied space is obtained. Numerical simulations show that in the modified actuator with two membranes in the cavity, the jet output velocity and vorticity of a created toroidal vortex at the actuator outlet can be increased by 80%, compared to the case with one membrane. The new geometry of a synthetic jet actuator with perpendicular membranes is to be implemented into the wind tunnel measurements to prove the use of a modified synthetic jet actuator as a device applicable for active flow control.

Cellular Computational Logic Using Toehold Switches.

The development of computational logic that carries programmable and predictable features is one of the key requirements for next-generation synthetic biological devices. Despite considerable progress, the construction of synthetic biological arithmetic logic units presents numerous challenges. In this paper, utilizing the unique advantages of RNA molecules in building complex logic circuits in the cellular environment, we demonstrate the RNA-only bitwise logical operation of XOR gates and basic arithmetic operations, including a half adder, a half subtractor, and a Feynman gate, in Escherichia coli. Specifically, de-novo-designed riboregulators, known as toehold switches, were concatenated to enhance the functionality of an OR gate, and a previously utilized antisense RNA strategy was further optimized to construct orthogonal NIMPLY gates. These optimized synthetic logic gates were able to be seamlessly integrated to achieve final arithmetic operations on small molecule inputs in cells. Toehold-switch-based ribocomputing devices may provide a fundamental basis for synthetic RNA-based arithmetic logic units or higher-order systems in cells.

Combating Infectious Diseases with Synthetic Biology.

Over the past decades, there have been numerous outbreaks, including parasitic, fungal, bacterial, and viral infections, worldwide. The rate at which infectious diseases are emerging is disproportionate to the rate of development for new strategies that could combat them. Therefore, there is an increasing demand to develop novel, specific, sensitive, and effective methods for infectious disease diagnosis and treatment. Designed synthetic systems and devices are becoming powerful tools to treat human diseases. The advancement in synthetic biology offers efficient, accurate, and cost-effective platforms for detecting and preventing infectious diseases. Herein we focus on the latest state of living theranostics and its implications.

Computational Analysis of Actuation Techniques Impact on the Flow Control around the Ahmed Body

Active flow control with jet devices is a promising approach for vehicle aerodynamics control. In this work an extended computational study is performed comparing three different actuation strategies for active flow control around the square back Ahmed body at Reynolds number 500,000 (based on the vehicle height). Numerical simulations are run using a Large Eddy Simulation (LES) approach, well adapted to calculate the unsteady high Reynolds number flow control using periodic jet devices. computations are validated comparing to in-house experiments for uncontrolled and some controlled cases. The novelty of this investigation is mainly related to the in-depth study of the base flow and actuation approaches by an accurate LES method and their comparison to experiments. Here, several simulations are performed to estimate the effect of active controls on the flow topology and the drag reduction. Beside the continuous blowing jet, three periodic actuation techniques including periodic blowing and suction as well as the zero flux synthetic jet devices are explored. The slots are implemented discontinuously in order to achieve a better control efficiency linked to vortex generation. In this framework, spectral analyses on global aerodynamical quantities, rear pressure/drag coefficient behavior examination as well as wake structure investigations are performed in order to compare these jet actuations. As a result, shear layer variations are observed during the blowing phase, but the main flow topology change occurs with suction and synthetic jets. Rear back pressure is therefore substantially increased.

Engineering synthetic RNA devices for cell control.

The versatility of RNA in sensing and interacting with small molecules, proteins and other nucleic acids while encoding genetic instructions for protein translation makes it a powerful substrate for engineering biological systems. RNA devices integrate cellular information sensing, processing and actuation of specific signals into defined functions and have yielded programmable biological systems and novel therapeutics of increasing sophistication. However, challenges centred on expanding the range of analytes that can be sensed and adding new mechanisms of action have hindered the full realization of the field's promise. Here, we describe recent advances that address these limitations and point to a significant maturation of synthetic RNA-based devices.

Biodegradable bioelectronics for biomedical applications.

Biodegradable polymers have been widely used in tissue engineering with the potential to be replaced by regenerative tissue. While conventional bionic interfaces are designed to be implanted in living tissue and organs permanently, biocompatible and biodegradable electronic materials are now progressing a paradigm shift towards transient and regenerative bionic engineering. For example, biodegradable bioelectronics can monitor physiologies in a body, transiently rehabilitate disease symptoms, and seamlessly form regenerative interfaces from synthetic electronic devices to tissues by reducing inflammatory foreign-body responses. Conventional electronic materials have not readily been considered biodegradable. However, several strategies have been adopted for designing electroactive and biodegradable materials systems: (1) conductive materials blended with biodegradable components, (2) molecularly engineered conjugated polymers with biodegradable moieties, (3) naturally derived conjugated biopolymers, and (4) aqueously dissolvable metals with encapsulating layers. In this review, we endeavor to present the technical bridges from electrically active and biodegradable material systems to edible and biodegradable electronics as well as transient bioelectronics with pre-clinical bio-instrumental applications, including biodegradable sensors, neural and tissue engineering, and intelligent drug delivery systems.

Antigen-Triggered Logic-Gating of DNA Nanodevices.

Synthetic nanoscale devices that reconfigure dynamically in response to physiological stimuli could offer new avenues for diagnostics and therapy. Here, we report a strategy for controlling the state of DNA nanodevices based on sensing antigens with IgG antibodies. To this end, we use IgG antibodies as structural elements to kinetically trap reconfigurable DNA origami structures in metastable states. Addition of soluble antigens displace the IgGs from the objects and triggers reconfiguration. We demonstrate this mechanism by antigen-triggered disassembly of DNA origami shells for two different IgGs and their cognate antigens, and we determined the corresponding dose response curves. We also describe the logic-gated actuation of DNA objects with combinations of antigens, as demonstrated with AND-type shells that disassemble only when two different antigens are detected simultaneously. We apply our system for the antigen-triggered release of molecular payload as exemplified by the release of virus particles that we loaded into the DNA origami shells. We expect our approach to be applicable in many types of DNA nanostructures and with many other IgG-antigen combinations.

Detection of pks Island mRNAs Using Toehold Sensors in Escherichia coli.

Synthetic biologists have applied biomolecular engineering approaches toward the goal of novel biological devices and have shown progress in diverse areas of medicine and biotechnology. Especially promising is the application of synthetic biological devices towards a novel class of molecular diagnostics. As an example, a de-novo-designed riboregulator called toehold switch, with its programmability and compatibility with field-deployable devices showed promising in vitro applications for viral RNA detection such as Zika and Corona viruses. However, the in vivo application of high-performance RNA sensors remains challenging due to the secondary structure of long mRNA species. Here, we introduced ‘Helper RNAs’ that can enhance the functionality of toehold switch sensors by mitigating the effect of secondary structures around a target site. By employing the helper RNAs, previously reported mCherry mRNA sensor showed improved fold-changes in vivo. To further generalize the Helper RNA approaches, we employed automatic design pipeline for toehold sensors that target the essential genes within the pks island, an important target of biomedical research in connection with colorectal cancer. The toehold switch sensors showed fold-changes upon the expression of full-length mRNAs that apparently depended sensitively on the identity of the gene as well as the predicted local structure within the target region of the mRNA. Still, the helper RNAs could improve the performance of toehold switch sensors in many instances, with up to 10-fold improvement over no helper cases. These results suggest that the helper RNA approaches can further assist the design of functional RNA devices in vivo with the aid of the streamlined automatic design software developed here. Further, our solutions for screening and stabilizing single-stranded region of mRNA may find use in other in vivo mRNA-sensing applications such as cas13 crRNA design, transcriptome engineering, and trans-cleaving ribozymes.

Biomolecular mechanisms for signal differentiation

SummaryCells can sense temporal changes of molecular signals, allowing them to predict environmental variations and modulate their behavior. This paper elucidates biomolecular mechanisms of time derivative computation, facilitating the design of reliable synthetic differentiator devices for a variety of applications, ultimately expanding our understanding of cell behavior. In particular, we describe and analyze three alternative biomolecular topologies that are able to work as signal differentiators to input signals around their nominal operation. We propose strategies to preserve their performance even in the presence of high-frequency input signal components which are detrimental to the performance of most differentiators. We find that the core of the proposed topologies appears in natural regulatory networks and we further discuss their biological relevance. The simple structure of our designs makes them promising tools for realizing derivative control action in synthetic biology.