Review: Sensors for Biosignal/Health Monitoring in Electronic Skin

Skin is the largest sensory organ and receives information from external stimuli. Human body signals have been monitored using wearable devices, which are gradually being replaced by electronic skin (E-skin). We assessed the basic technologies from two points of view: sensing mechanism and material. Firstly, E-skins were fabricated using a tactile sensor. Secondly, E-skin sensors were composed of an active component performing actual functions and a flexible component that served as a substrate. Based on the above fabrication processes, the technologies that need more development were introduced. All of these techniques, which achieve high performance in different ways, are covered briefly in this paper. We expect that patients’ quality of life can be improved by the application of E-skin devices, which represent an applied advanced technology for real-time bio- and health signal monitoring. The advanced E-skins are convenient and suitable to be applied in the fields of medicine, military and environmental monitoring.

Application of Conductive Polymer-Based Hydrogel in Multi-robot Balance Control

At present, the flexible electronic materials with both good flexibility and conductivity have become a major development trend of electronic materials in the future. Due to their flexibility in construction, controllable mechanical properties and electrical conductivity, the conductive polymer-based hydrogels (CPHs) are expected to become one of the candidate materials in flexible electronics and other fields, and have received extensive attention from researchers. However, the existing CPH systems generally have shortcomings such as low mechanical strength and single function. To this end, the authors attempt to construct a hydrogel using polyaniline (PANI) as the conductive component and polyacrylic acid (PAA) as the flexible component through in-situ polymerization and physical blending. The designed PAA/PANI conductive polymer-based hydrogel enjoys ultra-long stretchability and high strength. It can be used in the flexible strain sensors and pressure sensors to detect the step cycle of the multi-legged robot in real time, and adjust their rhythm during the walking gait, thereby achieving the physical balance. This paper provides a new idea for the application of the CPHs, and especially offers a wealth of theoretical foundation and practical experience for the research on its application to the flexible strain sensors.

Tension Control of a Web Fed Machine

The applications of web handling systems such as paper manufacturing, printing and film process, flexible component, paper manufacturing, textile.. are widely used in processing and manufacturing industry. In the application, tension control of the web plays a very crucial role. The mathematical model of the continuous web transport system is developed thanks to energy balance method. The paper presents a method of designing a tension control based on Linear Quadratic control. Several numerical simulation results are given to prove the effectiveness of the closed-loop system. In addition, the simulation results show incorrectness of another study in term of tension regulation.

Flexibility and Control of Circadian Activity, Migratory Restlessness and Fueling in Two Songbird Migrants

Juvenile songbirds rely on an endogenous program, encoding direction, distance, fueling, and timing of migration. Migratory distance is species-specific, expressed as a period of migratory restlessness, for which the length is correlated with distance, while fueling is modified to meet anticipated flight distances controlled by geomagnetic cues and amount of day-light available for foraging. How daylength affect onset and level of migratory activity and fueling decisions in wild birds have so far received limited attention. Here we study how photoperiod controls onset, level and extent of autumn migratory activity and fueling in juvenile diurnally migrating dunnocks, and nocturnally migrating European robins by experimentally increasing daylength. For both species, we kept a control group indoors at the location of capture in southern Sweden exposed to the natural photoperiod, and an experimental group with increased and advanced photoperiod by 2 h in the morning. Dunnocks initiated migratory activity at sunrise (or artificial sunrise) in both groups, demonstrating a highly responsive and flexible component for the onset of migration triggered by light. Experimental robins anticipated the end of nocturnal migratory activity predicting the earlier sunrise immediately after the time-shift and expressed this behavior already under darkness, supporting a fast-resetting mechanism to the new diel period. Timing of end of morning activity was not affected by the earlier sunrise in both species, suggesting a fixed endogenous control that persisted throughout the 13-day study period. Experimental dunnocks expressed higher overall activity and lower fuel loads than controls, while robins did not change their overall activity and fuel load in response to the shifted and increased photoperiod. These results reveal important adaptations for circadian timekeeping including both a flexible onset open to fast modifications and a more rigid end, with differential effects by the treatment on migratory activity and fueling in the two species.

A Practical, Component-Based Synthetic Route to Methylthiolincosamine Permitting Facile Northern-Half Diversification of Lincosamide Antibiotics

The development of a flexible, component-based synthetic route to the aminosugar fragment of the lincosamide antibiotics is described. This synthetic route hinges on the application and extension of nitroaldol chemistry to forge strategic bonds within complex aminosugar targets, and employs a glycal epoxide as a versatile glycosyl donor for the installation of various anomeric groups. Through building-block exchange and late-stage functionalization, this route affords access to a host of rationally designed lincosamides otherwise inaccessible by semisynthesis, and underpins a platform for the discovery of new lincosamide antibiotics.

A Practical, Component-Based Synthetic Route to Methylthiolincosamine Permitting Facile Northern-Half Diversification of Lincosamide Antibiotics

The development of a flexible, component-based synthetic route to the aminosugar fragment of the lincosamide antibiotics is described. This synthetic route hinges on the application and extension of nitroaldol chemistry to forge strategic bonds within complex aminosugar targets, and employs a glycal epoxide as a versatile glycosyl donor for the installation of various anomeric groups. Through building-block exchange and late-stage functionalization, this route affords access to a host of rationally designed lincosamides otherwise inaccessible by semisynthesis, and underpins a platform for the discovery of new lincosamide antibiotics.

Fabrication of Hard–Soft Microfluidic Devices Using Hybrid 3D Printing

Widely accessible, inexpensive, easy-to-use consumer 3D printers, such as desktop stereolithography (SLA) and fused-deposition modeling (FDM) systems are increasingly employed in prototyping and customizing miniaturized fluidic systems for diagnostics and research. However, these 3D printers are generally limited to printing parts made of only one material type, which limits the functionality of the microfluidic devices without additional assembly and bonding steps. Moreover, mating of different materials requires good sealing in such microfluidic devices. Here, we report methods to print hybrid structures comprising a hard, rigid component (clear polymethacrylate polymer) printed by a low-cost SLA printer, and where the first printed part is accurately mated and adhered to a second, soft, flexible component (thermoplastic polyurethane elastomer) printed by an FDM printer. The prescribed mounting and alignment of the first-printed SLA-printed hard component, and its pre-treatment and heating during the second FDM step, can produce leak-free bonds at material interfaces. To demonstrate the utility of such hybrid 3D-printing, we prototype and test three components: i) finger-actuated pump, ii) quick-connect fluid coupler, and iii) nucleic acid amplification test device with screw-type twist sealing for sample introduction.

On the Projection of a Flexible Bodies Modal Coordinates Onto Another Finite Element Model With Local Modifications

The time integration of a complex multibody system is a time consuming part of the entire evaluation process of a flexible component. A multibody simulation of a flexible crankshaft, for instance, interacting with pistons, con rods, fly wheel, hydrodynamic bearings and further takes several hours of central processing unit (CPU) time and may dominate the entire simulation chain. Small, local changes in the involved finite element (FE) models, for example, another notch radius, normally require a new time integration of the entire multibody system. In this publication, a remarkably simple method is presented, so that the multibody simulation of such a variant can be skipped entirely. Instead, a simple and cheap projection of the original results to the modified FE model is proposed. One simple and one elaborate example demonstrate the extraordinary resulting quality for minor design changes like notch radius variations.